WorldWideScience

Sample records for reversible chemical complexation

  1. Mass transfer with complex reversible chemical reactions—I. Single reversible chemical reaction

    NARCIS (Netherlands)

    Versteeg, G.F.; Kuipers, J.A.M.; Beckum, F.P.H. van; Swaaij, W.P.M. van

    1989-01-01

    An improved numerical technique was used in order to develop an absorption model with which it is possible to calculate rapidly absorption rates for the phenomenon of mass transfer accompanied by a complex reversible chemical reaction. This model can be applied for the calculation of the mass

  2. Mass transfer with complex reversible chemical reactions—II. parallel reversible chemical reactions

    NARCIS (Netherlands)

    Versteeg, G.F.; Kuipers, J.A.M.; Beckum, F.P.H. van; Swaaij, W.P.M. van

    1990-01-01

    An absorption model has been developed which can be used to calculate rapidly absorption rates for the phenomenon mass transfer accompanied by multiple complex parallel reversible chemical reactions. This model can be applied for the calculation of the mass transfer rates, enhancement factors and

  3. Mass transfer with complex reversible chemical reactions. II: Parallel reversible chemical reactions

    NARCIS (Netherlands)

    Versteeg, Geert; van Beckum, F.P.H.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    1990-01-01

    An absorption model has been developed which can be used to calculate rapidly absorption rates for the phenomenon mass transfer accompanied by multiple complex parallel reversible chemical reactions. This model can be applied for the calculation of the mass transfer rates, enhancement factors and

  4. Mass transfer with complex reversible chemical reactions. II: parallel reversible chemical reactions

    NARCIS (Netherlands)

    Versteeg, G.F.; Kuipers, J.A.M.; Beckum, van F.P.H.; van Swaaij, W.P.M.

    1990-01-01

    An absorption model has been developed which can be used to calculate rapidly absorption rates for the phenomenon mass transfer accompanied by multiple complex parallel reversible chemical reactions. This model can be applied for the calculation of the mass transfer rates, enhancement factors and

  5. Mass transfer with complex reversible chemical reactions—II. parallel reversible chemical reactions

    OpenAIRE

    Versteeg, G.F.; Kuipers, J.A.M.; Beckum, F.P.H. van; Swaaij, W.P.M. van

    1990-01-01

    An absorption model has been developed which can be used to calculate rapidly absorption rates for the phenomenon mass transfer accompanied by multiple complex parallel reversible chemical reactions. This model can be applied for the calculation of the mass transfer rates, enhancement factors and concentration profiles for a wide range of processes and conditions, for both film and penetration model. With the aid of this mass transfer model it is demonstrated that the absorption rates in syst...

  6. Chemical reactions in reverse micelle systems

    Science.gov (United States)

    Matson, Dean W.; Fulton, John L.; Smith, Richard D.; Consani, Keith A.

    1993-08-24

    This invention is directed to conducting chemical reactions in reverse micelle or microemulsion systems comprising a substantially discontinuous phase including a polar fluid, typically an aqueous fluid, and a microemulsion promoter, typically a surfactant, for facilitating the formation of reverse micelles in the system. The system further includes a substantially continuous phase including a non-polar or low-polarity fluid material which is a gas under standard temperature and pressure and has a critical density, and which is generally a water-insoluble fluid in a near critical or supercritical state. Thus, the microemulsion system is maintained at a pressure and temperature such that the density of the non-polar or low-polarity fluid exceeds the critical density thereof. The method of carrying out chemical reactions generally comprises forming a first reverse micelle system including an aqueous fluid including reverse micelles in a water-insoluble fluid in the supercritical state. Then, a first reactant is introduced into the first reverse micelle system, and a chemical reaction is carried out with the first reactant to form a reaction product. In general, the first reactant can be incorporated into, and the product formed in, the reverse micelles. A second reactant can also be incorporated in the first reverse micelle system which is capable of reacting with the first reactant to form a product.

  7. Mass transfer with complex chemical reactions in gas–liquid systems : two-step reversible reactions with unit stoichiometric and kinetic orders

    NARCIS (Netherlands)

    Vas Bhat, R.D.; Kuipers, J.A.M.; Versteeg, G.F.

    2000-01-01

    An absorption model to study gas–liquid mass transfer accompanied by reversible two-step reactions in the liquid phase has been presented. This model has been used to determine mass transfer rates, enhancement factors and concentration profiles over a wide range of process conditions. Although

  8. Mass transfer with complex chemical reactions in gas-liquid systems: two-step reversible reactions with unit stoichiometric and kinetic orders

    NARCIS (Netherlands)

    Vas bhat, R.D.; Kuipers, J.A.M.; Versteeg, Geert

    2000-01-01

    An absorption model to study gas¿liquid mass transfer accompanied by reversible two-step reactions in the liquid phase has been presented. This model has been used to determine mass transfer rates, enhancement factors and concentration profiles over a wide range of process conditions. Although

  9. Reverse preferential spread in complex networks

    Science.gov (United States)

    Toyoizumi, Hiroshi; Tani, Seiichi; Miyoshi, Naoto; Okamoto, Yoshio

    2012-08-01

    Large-degree nodes may have a larger influence on the network, but they can be bottlenecks for spreading information since spreading attempts tend to concentrate on these nodes and become redundant. We discuss that the reverse preferential spread (distributing information inversely proportional to the degree of the receiving node) has an advantage over other spread mechanisms. In large uncorrelated networks, we show that the mean number of nodes that receive information under the reverse preferential spread is an upper bound among any other weight-based spread mechanisms, and this upper bound is indeed a logistic growth independent of the degree distribution.

  10. Chemical boundary layers in CVD II. Reversible reactions

    NARCIS (Netherlands)

    Croon, de M.H.J.M.; Giling, L.J.

    1990-01-01

    In addition to irreversible reactions, which were treated in part I, reversible reactions in the gas phase have beenstudied using the concept of the chemical boundary layer. The analysis is given for the situations in which either the forwardor the back reaction is dominant. Two conceptual models

  11. Reversible targeting of noncatalytic cysteines with chemically tuned electrophiles

    DEFF Research Database (Denmark)

    Serafimova, Iana M; Pufall, Miles A; Krishnan, Shyam

    2012-01-01

    Targeting noncatalytic cysteine residues with irreversible acrylamide-based inhibitors is a powerful approach for enhancing pharmacological potency and selectivity. Nevertheless, concerns about off-target modification motivate the development of reversible cysteine-targeting strategies. Here we...... of these electrophiles into a noncovalent kinase-recognition scaffold produced slowly dissociating, covalent inhibitors of the p90 ribosomal protein S6 kinase RSK2. A cocrystal structure revealed specific noncovalent interactions that stabilize the complex by positioning the electrophilic carbon near the targeted...

  12. Copper complexes as chemical nucleases

    Indian Academy of Sciences (India)

    Unknown

    anticancer drug famotidine has been shown as a better catalyst than CuCl2 for sulfite ... Effect of addition of bis-chelate copper(II) complexes (dpq, •; phen, ; ..... Reproduction, Development & Genetics for their help in the DNA cleavage studies ...

  13. Symmetry Relations in Chemical Kinetics Arising from Microscopic Reversibility

    Science.gov (United States)

    Adib, Artur B.

    2006-01-01

    It is shown that the kinetics of time-reversible chemical reactions having the same equilibrium constant but different initial conditions are closely related to one another by a directly measurable symmetry relation analogous to chemical detailed balance. In contrast to detailed balance, however, this relation does not require knowledge of the elementary steps that underlie the reaction, and remains valid in regimes where the concept of rate constants is ill defined, such as at very short times and in the presence of low activation barriers. Numerical simulations of a model of isomerization in solution are provided to illustrate the symmetry under such conditions, and potential applications in protein folding or unfolding are pointed out.

  14. Chemical respiratory allergy: Reverse engineering an adverse outcome pathway

    International Nuclear Information System (INIS)

    Kimber, Ian; Dearman, Rebecca J.; Basketter, David A.; Boverhof, Darrell R.

    2014-01-01

    Allergic sensitisation of the respiratory tract by chemicals is associated with rhinitis and asthma and remains an important occupational health issue. Although less than 80 chemicals have been confirmed as respiratory allergens the adverse health effects can be serious, and in rare instances can be fatal, and there are, in addition, related socioeconomic issues. The challenges that chemical respiratory allergy pose for toxicologists are substantial. No validated methods are available for hazard identification and characterisation, and this is due in large part to the fact that there remains considerable uncertainty and debate about the mechanisms through which sensitisation of the respiratory tract is acquired. Despite that uncertainty, there is a need to establish some common understanding of the key events and processes that are involved in respiratory sensitisation to chemicals and that might in turn provide the foundations for novel approaches to safety assessment. In recent years the concept of adverse outcome pathways (AOP) has gained some considerable interest among the toxicology community as a basis for outlining the key steps leading to an adverse health outcome, while also providing a framework for focusing future research, and for developing alternative paradigms for hazard characterisation. Here we explore application of the same general principles to an examination of the induction by chemicals of respiratory sensitisation. In this instance, however, we have chosen to adopt a reverse engineering approach and to model a possible AOP for chemical respiratory allergy working backwards from the elicitation of adverse health effects to the cellular and molecular mechanisms that are implicated in the acquisition of sensitisation

  15. Characterization of reversible reactions of isocyanides with molybdenum dithiolate complexes

    International Nuclear Information System (INIS)

    Miller, D.J.; DuBois, M.R.

    1980-01-01

    Dimeric molybdenum complexes with bridging dithiocarbonimidate ligands of the formula [C 5 H 5 MoS 2 CNR] 2 (where R = CH 3 , CH 2 C 6 H 5 , C 6 H 11 , and n-C 4 H 9 ) have been synthesized and characterized. The syntheses involve the room-temperature reactions of excess isocyanides with solutions of the dimeric complex [C 5 H 5 MoSC 3 H 6 S] 2 . During the course of these reactions, propene is displaced from the sulfur atoms of the bridging dithiolate ligands. Addition of excess alkene reverses the above reactions. Equilibrium constants have been calculated for the following reactions by integration of NMR resonances: [CH 3 C 5 H 4 MoSC 2 H 4 S] 2 + RNC reversible (CH 3 C 5 H 4 Mo) 2 (SC 2 H 4 S)(S 2 CNR) + C == C, K 1 = 2.9 +- 0.2; (CH 3 C 5 H 4 Mo) 2 (SC 2 H 4 S)(S 2 CNR) + RNC reversible [CH 3 C 5 H 4 MoS 2 CNR] 2 + C == C, K 2 = 0.7 +- 0.1 (R = CH 2 C 6 H 5 ). The dithiocarbonimidate complexes react cleanly with the electrophiles CH 3 OSO 2 F and HOSO 2 CF 3 to form [C 5 H 5 MoS 2 CNRR'] 2 2+ where R' = H or CH 3 . These products have been characterized by spectral and conductivity methods. The reactions of the dithiocarbonimidate complexes with reducing agents and with carbon monoxide are discussed. 1 figure, 2 tables

  16. Experimental and theoretical investigation of topological and energetic characteristics of Sb complexes reversibly binding molecular oxygen.

    Science.gov (United States)

    Fukin, Georgy K; Baranov, Evgenii V; Jelsch, Christian; Guillot, Benoît; Poddel'sky, Andrey I; Cherkasov, Vladimir K; Abakumov, Gleb A

    2011-07-28

    The experimental distribution of electron density in Ph(3)(4,5-OMe-3,6-Bu(t)-Cat)Sb·MeCN (1*) and Ph(3)(4,5-N(2)C(4)H(6)-3,6-Bu(t)-Cat)Sb·MeOH (2*) complexes was studied. According to atoms in molecules theory, the Sb-C(Ph), Sb-O(catecholate), and Sb···N(O) bonds are intermediate, whereas the O-C and C-C bonds are covalent, respectively. The energy of the Sb···N(MeCN) and Sb···O(MeOH) bonds are 7.0 and 11.3 kcal/mol according to the Espinosa equation. Density functional theory and Hartree-Fock calculations were carried out for a series of catecholate and amidophenolate complexes of antimony(V). It was shown that such calculations reliably reproduce geometrical and topological parameters and therefore can be used for a criterion search of dioxygen reversible binding by the catecholate and amidophenolate complexes of antimony(V). It was found that the "critical" value of the HOMO energy vary in the range from -5.197 to -5.061 eV for reversible binding of dioxygen complexes. This can serve as a thermodynamic criterion to predict the possibility of the dioxygen reversible binding by the catecholate and amidophenolate complexes of Sb(V). The HOMO energies correlate with the conversion of the catecholate and amidophenolate complexes in corresponding spiroendoperoxide derivatives as well. The contribution of the atom orbitals of the carbon atoms in the five-membered metallocycle to HOMO in complexes with different substitutes in the 4- and 5-positions of the catecholate ligand allows predicting the place of dioxygen addition. © 2011 American Chemical Society

  17. Simulation of square wave voltammetry of three electrode reactions coupled by two reversible chemical reactions

    OpenAIRE

    Lovrić, Milivoj

    2017-01-01

    Three fast and reversible electrode reactions that are connected by two reversible chemical reactions that are permanently in the equilibrium are analysed theoretically for square wave voltammetry. The dependence of peak potentials on the dimensionless equilibrium constants of chemical reactions is calculated. The influence of the basic thermodynamic parameters on the square wave voltammetric responses is analysed.

  18. A rapidly-reversible absorptive and emissive vapochromic Pt(II) pincer-based chemical sensor.

    Science.gov (United States)

    Bryant, M J; Skelton, J M; Hatcher, L E; Stubbs, C; Madrid, E; Pallipurath, A R; Thomas, L H; Woodall, C H; Christensen, J; Fuertes, S; Robinson, T P; Beavers, C M; Teat, S J; Warren, M R; Pradaux-Caggiano, F; Walsh, A; Marken, F; Carbery, D R; Parker, S C; McKeown, N B; Malpass-Evans, R; Carta, M; Raithby, P R

    2017-11-27

    Selective, robust and cost-effective chemical sensors for detecting small volatile-organic compounds (VOCs) have widespread applications in industry, healthcare and environmental monitoring. Here we design a Pt(II) pincer-type material with selective absorptive and emissive responses to methanol and water. The yellow anhydrous form converts reversibly on a subsecond timescale to a red hydrate in the presence of parts-per-thousand levels of atmospheric water vapour. Exposure to methanol induces a similarly-rapid and reversible colour change to a blue methanol solvate. Stable smart coatings on glass demonstrate robust switching over 10 4 cycles, and flexible microporous polymer membranes incorporating microcrystals of the complex show identical vapochromic behaviour. The rapid vapochromic response can be rationalised from the crystal structure, and in combination with quantum-chemical modelling, we provide a complete microscopic picture of the switching mechanism. We discuss how this multiscale design approach can be used to obtain new compounds with tailored VOC selectivity and spectral responses.

  19. Chemical encapsulation of rocuronium by synthetic cyclodextrin derivatives: reversal of neuromuscular block in anaesthetized Rhesus monkeys.

    NARCIS (Netherlands)

    Boer, H.D. de; Egmond, J. van; Pol, F. van de; Bom, A.; Booij, L.H.D.J.

    2006-01-01

    BACKGROUND: At present, reversal of neuromuscular block induced by steroidal neuromuscular blocking agents (NMBAs) is achieved by administration of cholinesterase inhibitors. Chemical encapsulation of steroidal NMBAs, such as rocuronium, by a cyclodextrin is a new concept in neuromuscular block

  20. Microbial reverse-electrodialysis chemical-production cell for acid and alkali production

    KAUST Repository

    Zhu, Xiuping; Hatzell, Marta C.; Cusick, Roland D.; Logan, Bruce E.

    2013-01-01

    A new type of bioelectrochemical system, called a microbial reverse-electrodialysis chemical-production cell (MRCC), was developed to produce acid and alkali using energy derived from organic matter (acetate) and salinity gradients (NaCl solutions

  1. Modeling the Chemical Complexity in Titan's Atmosphere

    Science.gov (United States)

    Vuitton, Veronique; Yelle, Roger; Klippenstein, Stephen J.; Horst, Sarah; Lavvas, Panayotis

    2018-06-01

    Titan's atmospheric chemistry is extremely complicated because of the multiplicity of chemical as well as physical processes involved. Chemical processes begin with the dissociation and ionization of the most abundant species, N2 and CH4, by a variety of energy sources, i.e. solar UV and X-ray photons, suprathermal electrons (reactions involving radicals as well as positive and negative ions, all possibly in some excited electronic and vibrational state. Heterogeneous chemistry at the surface of the aerosols could also play a significant role. The efficiency and outcome of these reactions depends strongly on the physical characteristics of the atmosphere, namely pressure and temperature, ranging from 1.5×103 to 10-10 mbar and from 70 to 200 K, respectively. Moreover, the distribution of the species is affected by molecular diffusion and winds as well as escape from the top of the atmosphere and condensation in the lower stratosphere.Photochemical and microphysical models are the keystones of our understanding of Titan's atmospheric chemistry. Their main objective is to compute the distribution and nature of minor chemical species (typically containing up to 6 carbon atoms) and haze particles, respectively. Density profiles are compared to the available observations, allowing to identify important processes and to highlight those that remain to be constrained in the laboratory, experimentally and/or theoretically. We argue that positive ion chemistry is at the origin of complex organic molecules, such as benzene, ammonia and hydrogen isocyanide while neutral-neutral radiative association reactions are a significant source of alkanes. We find that negatively charged macromolecules (m/z ~100) attract the abundant positive ions, which ultimately leads to the formation of the aerosols. We also discuss the possibility that an incoming flux of oxygen from Enceladus, another Saturn's satellite, is responsible for the presence of oxygen-bearing species in Titan's reductive

  2. Echinacea complex--chemical view and anti-asthmatic profile.

    Science.gov (United States)

    Šutovská, Martina; Capek, Peter; Kazimierová, Ivana; Pappová, Lenka; Jošková, Marta; Matulová, Mária; Fraňová, Soňa; Pawlaczyk, Izabela; Gancarz, Roman

    2015-12-04

    Echinacea purpurea (L.) Moench is one of the mostly used herbs in the traditional medicine for the treatment of respiratory diseases. Modern interest in Echinacea is directed to its immunomodulatory activity. Recent studies have shown that secretion of asthma-related cytokines in the bronchial epithelial cells can be reversed by Echinacea preparations. To examine the pharmacodynamics profile of Echinacea active principles, a complex has been isolated from its flowers by alkaline extraction and has been tested using an animal model of allergic asthma. The structural features of Echinacea purpurea complex was determined using chemical and spectroscopic methods. Allergic inflammation of the airways was induced by repetitive exposure of guinea pigs to ovalbumin. Echinacea complex was then administered 14 days in 50mg/kg b.w. daily dose perorally. Bronchodilatory effect was verified as decrease in the specific airway resistance (sRaw) in vivo and by reduced contraction amplitude (mN) of tracheal and pulmonary smooth muscle to cumulative concentrations of acetylcholine and histamine in vitro. The impact on mucociliary clearance evaluated measurement of ciliary beat frequency (CBF) in vitro using LabVIEW™ Software. Anti-inflammatory effect of Echinacea complex was verified by changes in exhaled NO levels and by Bio-Plex® assay of Th2 cytokine concentrations (IL-4, IL-5, IL-13 and TNF-alpha) in serum and bronchoalveolar lavage fluid (BALF). Chemical and spectroscopic studies confirmed the presence of carbohydrates, phenolic compounds and proteins, as well as the dominance of rhamnogalacturonan and arabinogalactan moieties in Echinacea complex. The significant decrease in sRaw values and suppressed histamine and acetylcholine-induced contractile amplitude of isolated airways smooth muscle that were similar to effects of control drug salbutamol confirmed Echinacea complex bronchodilatory activity. The anti-inflammatory effect was comparable with that of control agent

  3. Modeling Complex Chemical Systems: Problems and Solutions

    Science.gov (United States)

    van Dijk, Jan

    2016-09-01

    Non-equilibrium plasmas in complex gas mixtures are at the heart of numerous contemporary technologies. They typically contain dozens to hundreds of species, involved in hundreds to thousands of reactions. Chemists and physicists have always been interested in what are now called chemical reduction techniques (CRT's). The idea of such CRT's is that they reduce the number of species that need to be considered explicitly without compromising the validity of the model. This is usually achieved on the basis of an analysis of the reaction time scales of the system under study, which identifies species that are in partial equilibrium after a given time span. The first such CRT that has been widely used in plasma physics was developed in the 1960's and resulted in the concept of effective ionization and recombination rates. It was later generalized to systems in which multiple levels are effected by transport. In recent years there has been a renewed interest in tools for chemical reduction and reaction pathway analysis. An example of the latter is the PumpKin tool. Another trend is that techniques that have previously been developed in other fields of science are adapted as to be able to handle the plasma state of matter. Examples are the Intrinsic Low Dimension Manifold (ILDM) method and its derivatives, which originate from combustion engineering, and the general-purpose Principle Component Analysis (PCA) technique. In this contribution we will provide an overview of the most common reduction techniques, then critically assess the pros and cons of the methods that have gained most popularity in recent years. Examples will be provided for plasmas in argon and carbon dioxide.

  4. A reversible, unidirectional molecular rotary motor driven by chemical energy

    NARCIS (Netherlands)

    Fletcher, SP; Dumur, F; Pollard, MM; Feringa, BL

    2005-01-01

    With the long-term goal of producing nanometer-scale machines, we describe here the unidirectional rotary motion of a synthetic molecular structure fueled by chemical conversions. The basis of the rotation is the movement,of a phenyl rotor relative to a naphthyl stator about a single bond axle. The

  5. Predicting skin permeability from complex chemical mixtures

    International Nuclear Information System (INIS)

    Riviere, Jim E.; Brooks, James D.

    2005-01-01

    Occupational and environmental exposure to topical chemicals is usually in the form of complex chemical mixtures, yet risk assessment is based on experimentally derived data from individual chemical exposures from a single, usually aqueous vehicle, or from computed physiochemical properties. We present an approach using hybrid quantitative structure permeation relationships (QSPeR) models where absorption through porcine skin flow-through diffusion cells is well predicted using a QSPeR model describing the individual penetrants, coupled with a mixture factor (MF) that accounts for physicochemical properties of the vehicle/mixture components. The baseline equation is log k p = c + mMF + aΣα 2 H + bΣβ 2 H + sπ 2 H + rR 2 + vV x where Σα 2 H is the hydrogen-bond donor acidity, Σβ 2 H is the hydrogen-bond acceptor basicity, π 2 H is the dipolarity/polarizability, R 2 represents the excess molar refractivity, and V x is the McGowan volume of the penetrants of interest; c, m, a, b, s, r, and v are strength coefficients coupling these descriptors to skin permeability (k p ) of 12 penetrants (atrazine, chlorpyrifos, ethylparathion, fenthion, methylparathion, nonylphenol, ρ-nitrophenol, pentachlorophenol, phenol, propazine, simazine, and triazine) in 24 mixtures. Mixtures consisted of full factorial combinations of vehicles (water, ethanol, propylene glycol) and additives (sodium lauryl sulfate, methyl nicotinate). An additional set of 4 penetrants (DEET, SDS, permethrin, ricinoleic acid) in different mixtures were included to assess applicability of this approach. This resulted in a dataset of 16 compounds administered in 344 treatment combinations. Across all exposures with no MF, R 2 for absorption was 0.62. With the MF, correlations increased up to 0.78. Parameters correlated to the MF include refractive index, polarizability and log (1/Henry's Law Constant) of the mixture components. These factors should not be considered final as the focus of these studies

  6. Reversibility and Relaxation Behavior of Polyelectrolyte Complex Micelle Formation

    NARCIS (Netherlands)

    Lindhoud, Saskia; Norde, Willem; Stuart, Martien A. Cohen

    2009-01-01

    In this study, the formation and disintegration of polyelectrolyte complex micelles is studied by dynamic light scattering titrations with the aim to assess the extent to which these complexes equilibrate. Also, the time evolution of samples at fixed (electroneutral) composition was followed to

  7. Do high school chemistry examinations inhibit deeper level understanding of dynamic reversible chemical reactions?

    Science.gov (United States)

    Wheeldon, R.; Atkinson, R.; Dawes, A.; Levinson, R.

    2012-07-01

    Background and purpose : Chemistry examinations can favour the deployment of algorithmic procedures like Le Chatelier's Principle (LCP) rather than reasoning using chemical principles. This study investigated the explanatory resources which high school students use to answer equilibrium problems and whether the marks given for examination answers require students to use approaches beyond direct application of LCP. Sample : The questionnaire was administered to 162 students studying their first year of advanced chemistry (age 16/17) in three high achieving London high schools. Design and methods : The students' explanations of reversible chemical systems were inductively coded to identify the explanatory approaches used and interviews with 13 students were used to check for consistency. AS level examination questions on reversible reactions were analysed to identify the types of explanations sought and the students' performance in these examinations was compared to questionnaire answers. Results : 19% of students used a holistic explanatory approach: when the rates of forward and reverse reactions are correctly described, recognising their simultaneous and mutually dependent nature. 36% used a mirrored reactions approach when the connected nature of the forward and reverse reactions is identified, but not their mutual dependency. 42% failed to recognize the interdependence of forward and reverse reactions (reactions not connected approach). Only 4% of marks for AS examination questions on reversible chemical systems asked for responses which went beyond either direct application of LCP or recall of equilibrium knowledge. 37% of students attained an A grade in their AS national examinations. Conclusions : Examinations favour the application of LCP making it possible to obtain the highest grade with little understanding of reversible chemical systems beyond a direct application of this algorithm. Therefore students' understanding may be attenuated so that they are

  8. Reversible photochromic system based on rhodamine B salicylaldehyde hydrazone metal complex.

    Science.gov (United States)

    Li, Kai; Xiang, Yu; Wang, Xiaoyan; Li, Ji; Hu, Rongrong; Tong, Aijun; Tang, Ben Zhong

    2014-01-29

    Photochromic molecules are widely applied in chemistry, physics, biology, and materials science. Although a few photochromic systems have been developed before, their applications are still limited by complicated synthesis, low fatigue resistance, or incomplete light conversion. Rhodamine is a class of dyes with excellent optical properties including long-wavelength absorption, large absorption coefficient, and high photostability in its ring-open form. It is an ideal chromophore for the development of new photochromic systems. However, known photochromic rhodamine derivatives, such as amides, exhibit only millisecond lifetimes in their colored ring-open forms, making their application very limited and difficult. In this work, rhodamine B salicylaldehyde hydrazone metal complex was found to undergo intramolecular ring-open reactions upon UV irradiation, which led to a distinct color and fluorescence change both in solution and in solid matrix. The complex showed good fatigue resistance for the reversible photochromism and long lifetime for the ring-open state. Interestingly, the thermal bleaching rate was tunable by using different metal ions, temperatures, solvents, and chemical substitutions. It was proposed that UV light promoted isomerization of the rhodamine B derivative from enol-form to keto-form, which induced ring-opening of the rhodamine spirolactam in the complex to generate color. The photochromic system was successfully applied for photoprinting and UV strength measurement in the solid state. As compared to other reported photochromic molecules, the system in this study has its advantages of facile synthesis and tunable thermal bleaching rate, and also provides new insights into the development of photochromic materials based on metal complex and spirolactam-containing dyes.

  9. Chemical-looping combustion in a reverse-flow fixed bed reactor

    International Nuclear Information System (INIS)

    Han, Lu; Bollas, George M.

    2016-01-01

    A reverse-flow fixed bed reactor concept for CLC (chemical-looping combustion) is explored. The limitations of conventional fixed bed reactors, as applied to CLC, are overcome by reversing the gas flow direction periodically to enhance the mixing characteristics of the bed, thus improving oxygen carrier utilization and energy efficiency with respect to power generation. The reverse-flow reactor is simulated by a dusty-gas model and compared with an equivalent fixed bed reactor without flow reversal. Dynamic optimization is used to calculate conditions at which each reactor operates at maximum energy efficiency. Several cases studies illustrate the benefits of reverse-flow operation for the CLC with CuO and NiO oxygen carriers and methane and syngas fuels. The results show that periodic reversal of the flow during reduction improves the contact between the fuel and unconverted oxygen carrier, enabling the system to suppress unwanted catalytic reactions and axial temperature and conversion gradients. The operational scheme presented reduces the fluctuations of temperature during oxidation and increases the high-temperature heat produced by the process. CLC in a reverse-flow reactor has the potential to achieve higher energy efficiency than conventional fixed bed CLC reactors, when integrated with a downstream gas turbine of a combined cycle power plant. - Highlights: • Reverse-flow fixed bed CLC reactors for combined cycle power systems. • Dynamic optimization tunes operation of batch and transient CLC systems. • The reverse-flow CLC system provides stable turbine-ready gas stream. • Reverse-flow CLC fixed bed reactor has superior CO 2 capture and thermal efficiency.

  10. Chemical treatment of commercial reverse osmosis membranes for use in FO

    Science.gov (United States)

    Commercially available reverse osmosis (RO) membranes – SW30HR, BW30, and AG – were chemically treated for use in forward osmosis (FO). Nitric acid, phosphoric acid, sulfuric acid, ethanol, and ethanol–acid–water ternary solutions were employed for the treatment. All three membra...

  11. On the graph and systems analysis of reversible chemical reaction networks with mass action kinetics

    NARCIS (Netherlands)

    Rao, Shodhan; Jayawardhana, Bayu; Schaft, Arjan van der

    2012-01-01

    Motivated by the recent progresses on the interplay between the graph theory and systems theory, we revisit the analysis of reversible chemical reaction networks described by mass action kinetics by reformulating it using the graph knowledge of the underlying networks. Based on this formulation, we

  12. Complex Chemical Reaction Networks from Heuristics-Aided Quantum Chemistry.

    Science.gov (United States)

    Rappoport, Dmitrij; Galvin, Cooper J; Zubarev, Dmitry Yu; Aspuru-Guzik, Alán

    2014-03-11

    While structures and reactivities of many small molecules can be computed efficiently and accurately using quantum chemical methods, heuristic approaches remain essential for modeling complex structures and large-scale chemical systems. Here, we present a heuristics-aided quantum chemical methodology applicable to complex chemical reaction networks such as those arising in cell metabolism and prebiotic chemistry. Chemical heuristics offer an expedient way of traversing high-dimensional reactive potential energy surfaces and are combined here with quantum chemical structure optimizations, which yield the structures and energies of the reaction intermediates and products. Application of heuristics-aided quantum chemical methodology to the formose reaction reproduces the experimentally observed reaction products, major reaction pathways, and autocatalytic cycles.

  13. Permutation entropy and statistical complexity in characterising low-aspect-ratio reversed-field pinch plasma

    International Nuclear Information System (INIS)

    Onchi, T; Fujisawa, A; Sanpei, A; Himura, H; Masamune, S

    2017-01-01

    Permutation entropy and statistical complexity are measures for complex time series. The Bandt–Pompe methodology evaluates probability distribution using permutation. The method is robust and effective to quantify information of time series data. Statistical complexity is the product of Jensen–Shannon divergence and permutation entropy. These physical parameters are introduced to analyse time series of emission and magnetic fluctuations in low-aspect-ratio reversed-field pinch (RFP) plasma. The observed time-series data aggregates in a region of the plane, the so-called C – H plane, determined by entropy versus complexity. The C – H plane is a representation space used for distinguishing periodic, chaos, stochastic and noisy processes of time series data. The characteristics of the emissions and magnetic fluctuation change under different RFP-plasma conditions. The statistical complexities of soft x-ray emissions and magnetic fluctuations depend on the relationships between reversal and pinch parameters. (paper)

  14. A molecular theory of chemically modified electrodes with self-assembled redox polyelectrolye thin films: Reversible cyclic voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Tagliazucchi, Mario; Calvo, Ernesto J. [INQUIMAE, DQIAyQF Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires (Argentina); Szleifer, Igal [Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)

    2008-10-01

    A molecular theory of chemically modified electrodes is applied to study redox polyelectroyte modified electrodes. The molecular approach explicitly includes the size, shape, charge distribution, and conformations of all of the molecular species in the system as well as the chemical equilibria (redox and acid-base) and intermolecular interactions. An osmium pyridine-bipyridine complex covalently bound to poly(allyl-amine) backbone (PAH-Os) adsorbed onto mercapto-propane sulfonate (MPS) thiolated gold electrode is described. The potential and electrolyte composition dependent redox and nonredox capacitance can be calculated with the molecular theory in very good agreement with voltammetric experiments under reversible conditions without the use of freely adjustable parameter. Unlike existing phenomenological models the theory links the electrochemical behavior with the structure of the polymer layer. The theory predicts a highly inhomogeneous distribution of acid-base and redox states that strongly couples with the spatial arrangement of the molecular species in the nanometric redox film. (author)

  15. The Streaming Complexity of Cycle Counting, Sorting by Reversals, and Other Problems

    DEFF Research Database (Denmark)

    Verbin, Elad; Yu, Wei

    2011-01-01

    -way. By designing reductions from BHH, we prove lower bounds for the streaming complexity of approximating the sorting by reversal distance, of approximately counting the number of cycles in a 2-regular graph, and of other problems. For example, here is one lower bound that we prove, for a cycle-counting problem...

  16. Synthetically chemical-electrical mechanism for controlling large scale reversible deformation of liquid metal objects

    Science.gov (United States)

    Zhang, Jie; Sheng, Lei; Liu, Jing

    2014-11-01

    Reversible deformation of a machine holds enormous promise across many scientific areas ranging from mechanical engineering to applied physics. So far, such capabilities are still hard to achieve through conventional rigid materials or depending mainly on elastomeric materials, which however own rather limited performances and require complicated manipulations. Here, we show a basic strategy which is fundamentally different from the existing ones to realize large scale reversible deformation through controlling the working materials via the synthetically chemical-electrical mechanism (SCHEME). Such activity incorporates an object of liquid metal gallium whose surface area could spread up to five times of its original size and vice versa under low energy consumption. Particularly, the alterable surface tension based on combination of chemical dissolution and electrochemical oxidation is ascribed to the reversible shape transformation, which works much more flexible than many former deformation principles through converting electrical energy into mechanical movement. A series of very unusual phenomena regarding the reversible configurational shifts are disclosed with dominant factors clarified. This study opens a generalized way to combine the liquid metal serving as shape-variable element with the SCHEME to compose functional soft machines, which implies huge potential for developing future smart robots to fulfill various complicated tasks.

  17. Extension of association models to complex chemicals

    DEFF Research Database (Denmark)

    Avlund, Ane Søgaard

    Summary of “Extension of association models to complex chemicals”. Ph.D. thesis by Ane Søgaard Avlund The subject of this thesis is application of SAFT type equations of state (EoS). Accurate and predictive thermodynamic models are important in many industries including the petroleum industry......; CPA and sPC-SAFT. Phase equilibrium and monomer fraction calculations with sPC-SAFT for methanol are used in the thesis to illustrate the importance of parameter estimation when using SAFT. Different parameter sets give similar pure component vapor pressure and liquid density results, whereas very...... association is presented in the thesis, and compared to the corresponding lattice theory. The theory for intramolecular association is then applied in connection with sPC-SAFT for mixtures containing glycol ethers. Calculations with sPC-SAFT (without intramolecular association) are presented for comparison...

  18. Open complex-balanced mass action chemical reaction networks

    NARCIS (Netherlands)

    Rao, Shodhan; van der Schaft, Arjan; Jayawardhana, Bayu

    We consider open chemical reaction networks, i.e. ones with inflows and outflows. We assume that all the inflows to the network are constant and all outflows obey the mass action kinetics rate law. We define a complex-balanced open reaction network as one that admits a complex-balanced steady state.

  19. Health and environmental effects of complex chemical mixtures: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    The Office of Health and Environmental Research (OHER) of the Department of Energy supports a broad long-term research program on human health and environmental effects from potential exposure to energy-related complex chemical mixtures. The program seeks basic mechanistic data on the effects of complex mixtures at the cellular, molecular, and whole animal levels to aid in predicting human health effects and seeks ecological data on biological and physical transformations in the mixtures, concentrations of the mixtures in various compartments of the environment, and potential routes for human exposure to these mixtures (e.g., food chain). On June 17-18, 1985, OHER held its First Annual Technical Meeting on the Complex Chemical Mixtures Program in Chicago, IL. The primary purpose of the meeting was to enable principal investigators to report the research status and accomplishments of ongoing complex chemical mixture studies supported by OHER. To help focus future research directions round table discussions were conducted.

  20. Water-chemical regime of a fast reactor ower complex

    International Nuclear Information System (INIS)

    Musikhin, R.N.; Piskunov, E.M.; Samarkin, A.A.; Yurchenko, D.S.

    1983-01-01

    Some peculiarities of water-chemical regime of a power compleX in Shevchenko are considered. The complex comprises a desalination unit, a gas-masout heating-and-power plant and the BN-350 reactor. The compleX is used for the production of electric and thermal energy and fresh water. The power complex peculiarity is the utilization of disalinated seawater in a technological cycle along with highly mineralized seawater with a total salt content of 13.5 g/l (for cooling) in heat exchanges. A regime of ammoniacal correction of feed water was used as a basic water-chemical regime in the initial period of the BN-350 steam generator operation. Deposits composed mainly of iron oxide slime were observed on steam generator surfaces during the operation under these conditions. A conclusion is made that the regime with chelating agent providing steam generator safe operation without chemical cleaning is the most expedient one

  1. Determinants of reverse knowledge transfer for emerging market multinationals: the role of complexity, autonomy and embeddedness

    Directory of Open Access Journals (Sweden)

    Franciane Freitas Silveira

    Full Text Available Abstract Subsidiaries conduct innovation activities in foreign markets either to capture valuable knowledge that is necessary to adapt their products to local markets or to create valuable knowledge for headquarters. For emerging market multinationals, most studies have overlooked the determinants of successful reverse knowledge transfer from subsidiaries located in emerging and developed markets. This paper analyzed the responses of a survey administered to 78 Brazilian multinationals that own subsidiaries in developed and emerging markets. We found that knowledge complexity developed at the subsidiary, its autonomy and embeddedness in the foreign market determine the successful reverse knowledge transfer to headquarters of emerging market multinationals. This paper contributes to previous studies of reverse knowledge transfer by underlying the main drivers for emerging market multinationals.

  2. Nanoscale control of reversible chemical reaction between fullerene C60 molecules using scanning tunneling microscope.

    Science.gov (United States)

    Nakaya, Masato; Kuwahara, Yuji; Aono, Masakazu; Nakayama, Tomonobu

    2011-04-01

    The nanoscale control of reversible chemical reactions, the polymerization and depolymerization between C60 molecules, has been investigated. Using a scanning tunneling microscope (STM), the polymerization and depolymerization can be controlled at designated positions in ultrathin films of C60 molecules. One of the two chemical reactions can be selectively induced by controlling the sample bias voltage (V(s)); the application of negative and positive values of V(s) results in polymerization and depolymerization, respectively. The selectivity between the two chemical reactions becomes extremely high when the thickness of the C60 film increases to more than three molecular layers. We conclude that STM-induced negative and positive electrostatic ionization are responsible for the control of the polymerization and depolymerization, respectively.

  3. Reversible photocontrol of molecular assemblies of metal complex containing azo-amphiphiles

    International Nuclear Information System (INIS)

    Einaga, Yasuaki; Mikami, Rie; Akitsu, Takashiro; Li, Guangming

    2005-01-01

    Photo-controllable molecular systems, [M(en) 2 ][Pt(en) 2 Cl 2 ](1) 4 (M 2+ =Pt 2+ , Pd 2+ and en=ethylenediamine), have been designed by the self-assembly of chloride-bridged platinum/palladium complexes and photochromic amphiphiles of the azobenzene derivative, 4-[4-(N-methyl-N-n-dodecylamino)phenylazo]benzene sulfonic acid (designated as compound 1). Reversible structural changes caused by cis-trans photoisomerization of azo groups in compound 1 were observed by alternating illumination of UV and visible light. Visible illumination resulted in the formation of the plate-like structures, whereas UV illumination resulted in fragmentation of the assembling structures. Reversible changes were observed in the electronic states of the chloride-bridged platinum/palladium complexes; the plate-like structures exhibited charge transfer absorption of chloride-bridged platinum complexes and delocalized Pt(II)/Pt(IV) states, while the fragments of the separated complexes exhibited no charge transfer bands. As a consequence, we have discovered that the reversible structural changes in this system could be controlled by photoillumination

  4. Estrogenic chemical effects are independent from the degree of sex role reversal in pipefish.

    Science.gov (United States)

    Sárria, Marisa P; Santos, Miguel M; Castro, L Filipe C; Vieira, Natividade M; Monteiro, Nuno M

    2013-12-15

    Endocrine disrupting chemicals (EDCs) have been reported to disturb several ecological relevant endpoints. Surprisingly, EDC-induced effects on fish sexual behaviour have been poorly studied despite the fact that even subtle alterations might contribute to a disruption of sexual interactions, thus negatively impacting reproduction. As the few assessments on sexual behaviour have been conducted in species with orthodox sex roles, it might be argued that sex-role reversed species might provide a potentially complementary system to further explore the effects of EDCs on reproduction. In the present study, two pipefish species with distinct degrees of sex-role reversal were selected to further elucidate the impact of chronic EE2 exposure on sexual behaviour and reproduction-related endpoints. The obtained results indicate that, independently of the degree of sex role reversal, courtship behaviour seems to resist oestrogenic chemical exposure. However, exposure to environmentally relevant EE2 levels did induce a complete absence of pregnancies at 18 ng/L. Even though pregnancies were observed at intermediate concentrations, the percentage of non-transferred or misplaced oocytes increased and a dose-dependent decrease of oocyte volume was observed. Imbalances in the oogenesis process, induction of vitellogenin in males and the absence of pregnancies highlight that environmental relevant concentrations of EE2 have the potential to negatively affect pipefish populations, most of them inhabiting coastal areas where oestrogenic contamination is more prevalent. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Chemometrics as a tool to analyse complex chemical mixtures

    DEFF Research Database (Denmark)

    Christensen, J. H.

    Chemical characterisation of contaminant mixtures is important for environmental forensics and risk assessment. The great challenge in future research lies in develop- ing suitable, rapid, reliable and objective methods for analysis of the composition of complex chemical mixtures. This thesis...... describes the development of such methods for assessing the identity (chemical fingerprinting) and fate (e.g. biodegradation) of petroleum hydrocarbon mixtures. The methods comply with the general concept that suitable methods must be rapid and inexpensive, objective with limited human in- tervention...... and at the same time must consider a substantial fraction of compounds in the complex mixture. A combination of a) limited sample preparation, b) rapid chemical screening analysis, c) fast and semi-automatic pre-processing, d) compre- hensive multivariate statistical data analysis and e) objective data evaluation...

  6. The effect of flow and chemical corrosion in reverse osmosis over desalinated water

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Jae [Chunnam National Univ., Gwangju (Korea, Republic of); Pak, Byung Gu [Doosan Heavy Industry Co., Tongyoung (Korea, Republic of)

    2015-12-15

    Desalinated water produced by a reverse osmosis (RO) filtering method forms about 22% of total production of desalinated water in the world. However, the RO environment is very corrosive due to the presence of various chemicals for water treatment and the flow of sand particles leading to corrosion. Recently, there has been much effort to substitute cheaper and more corrosion resistant stainless steels for copper based alloys as a valve material in RO. Nevertheless, the effects of chemicals and particles on the corrosion of stainless steels have rarely been studied. Erosion phenomenon was detected under the condition with the flow rate of more than 8ms{sup -1} in spite of the absence of sand particles. In seawater containing sand particles, the erosion in stainless steels was accelerated further.

  7. Quantum chemical prediction of antennae structures in lanthanide complexes

    International Nuclear Information System (INIS)

    Ottonelli, M.; Musso, G.F.; Rizzo, F.; Dellepiane, G.; Porzio, W.; Destri, S.

    2008-01-01

    In this paper the quantum chemical semiempirical procedure recently proposed by us to predict ground- and excited-state geometries of lanthanide complexes, the pseudo coordination centre method (PCC), is preliminarily compared with the semiempirical sparkle model for the calculation of lanthanide complexes (SMLC). Contrary to the SMLC method, where the rare-earth ion is replaced by a reparameterized sparkle atom, in our approach we replace it with a metal ion which is already present in the chosen semiempirical parameterization. This implies that in the optimization of the geometry of the complexes a different weight is implicitly given to the complex region including the rare-earth ion and its neighbour atoms with respect to the region of the ligands aggregate. As a consequence our approach is expected to reproduce better than the SMLC one the geometry of the ligands aggregate embedded in the complex, while the contrary happens for the coordination distances

  8. Microbial reverse-electrodialysis chemical-production cell for acid and alkali production

    KAUST Repository

    Zhu, Xiuping

    2013-06-01

    A new type of bioelectrochemical system, called a microbial reverse-electrodialysis chemical-production cell (MRCC), was developed to produce acid and alkali using energy derived from organic matter (acetate) and salinity gradients (NaCl solutions representative of seawater and river water). A bipolar membrane (BPM) was placed next to the anode to prevent Cl- contamination and acidification of the anolyte, and to produce protons for HCl recovery. A 5-cell paired reverse-electrodialysis (RED) stack provided the electrical energy required to overcome the BPM over-potential (0.3-0.6 V), making the overall process spontaneous. The MRCC reactor produced electricity (908 mW/m2) as well as concentrated acidic and alkaline solutions, and therefore did not require an external power supply. After a fed-batch cycle, the pHs of the chemical product solutions were 1.65 ± 0.04 and 11.98 ± 0.10, due to the production of 1.35 ± 0.13 mmol of acid, and 0.59 ± 0.14 mmol of alkali. The acid- and alkali-production efficiencies based on generated current were 58 ± 3% and 25 ± 3%. These results demonstrated proof-of-concept acid and alkali production using only renewable energy sources. © 2013 Elsevier B.V.

  9. Reversible chemical patterning on stimuli-responsive polymer film: Environment-responsive lithography

    International Nuclear Information System (INIS)

    Ionov, Leonid; Minko, Sergiy; Stamm, Manfred; Gohy, Jean-Francois; Jerome, Robert; Scholl, Andreas

    2003-01-01

    We report on a novel type of chemical patterning based on thin stimuli-responsive polymer films. The basic concept is the permanent storage (writing) of a pattern, which is reversibly developed and erased upon exposure to appropriate environment, e.g., solvent, pH, and temperature. The smart surface is fabricated from the mixed brush of poly(2-vinylpyridine) and polyisoprene. The mixed brush demonstrates switching behavior upon exposure to different solvents. Cross-linking of polyisoprene via illumination through a photomask results in formation of patterns with suppressed switching. Due to the contrast in switching between illuminated and dark areas, exposure of the smart surface to different solvents causes either reversible formation or erasing of chemical contrast between the illuminated and dark areas. Thus, the pattern surface can very locally attract colloidal particles or can be wetted by water only upon exposure to the special solvent which introduces the contrast between the illuminated and dark areas. Appearance of the patterns indicates particular environment and can be used for local switching of adsorption

  10. Dabigatran and its reversal with recombinant factor VIIa and prothrombin complex concentrate

    DEFF Research Database (Denmark)

    Sølbeck, Sacha; Nilsson, Caroline U; Engström, Martin

    2014-01-01

    OBJECTIVE: Dabigatran is a new oral direct thrombin inhibitor. No specific antidote exists in the event of hemorrhage, but prothrombin complex concentrate (PCC) and recombinant activated factor VII (rFVIIa) are suggested therapies. Sonoclot is a bedside viscoelastic instrument for monitoring...... different Sonoclot cuvettes: Glassbead, kaolin and tissue factor (diluted) activated. RESULTS: The Sonoclot detected in vitro-induced anticoagulation due to dabigatran with the glassbead- and kaolin-activated cuvettes. There was no reversing effect of PCC, probably due to the presence of heparin in the PCC...

  11. Reversible alkyne insertion in the benzannulation reaction of Fischer carbene complexes with alkynes

    Energy Technology Data Exchange (ETDEWEB)

    Waters, M.L.; Bos, M.E.; Wulff, W.D. [Univ. of Chicago, IL (United States)

    1995-12-31

    The benzannulation reaction of Fischer carbene complexes with alkynes to give phenols is highly regioselective with terminal alkynes, and reasonably regioselective with internal alkynes. This has been attributed to steric factors in intermediates, where one form is favored due to close contact between the R substituent and a cis-CO ligand. Whether alkyne insertion is kinetically or thermodynamically controlled has not been determined. The authors now have evidence from regioselectivity studies that alkyne insertion into the metal-carbon bond is reversible. Implications of these results and further mechanistic considerations will be presented.

  12. Radiological and chemical source terms for Solid Waste Operations Complex

    International Nuclear Information System (INIS)

    Boothe, G.F.

    1994-01-01

    The purpose of this document is to describe the radiological and chemical source terms for the major projects of the Solid Waste Operations Complex (SWOC), including Project W-112, Project W-133 and Project W-100 (WRAP 2A). For purposes of this document, the term ''source term'' means the design basis inventory. All of the SWOC source terms involve the estimation of the radiological and chemical contents of various waste packages from different waste streams, and the inventories of these packages within facilities or within a scope of operations. The composition of some of the waste is not known precisely; consequently, conservative assumptions were made to ensure that the source term represents a bounding case (i.e., it is expected that the source term would not be exceeded). As better information is obtained on the radiological and chemical contents of waste packages and more accurate facility specific models are developed, this document should be revised as appropriate. Radiological source terms are needed to perform shielding and external dose calculations, to estimate routine airborne releases, to perform release calculations and dose estimates for safety documentation, to calculate the maximum possible fire loss and specific source terms for individual fire areas, etc. Chemical source terms (i.e., inventories of combustible, flammable, explosive or hazardous chemicals) are used to determine combustible loading, fire protection requirements, personnel exposures to hazardous chemicals from routine and accident conditions, and a wide variety of other safety and environmental requirements

  13. Evidence from lava flows for complex polarity transitions: The new composite Steens Mountain reversal record

    Science.gov (United States)

    Jarboe, Nicholas A.; Coe, Robert S.; Glen, Jonathan M. G.

    2011-01-01

    Geomagnetic polarity transitions may be significantly more complex than are currently depicted in many sedimentary and lava-flow records. By splicing together paleomagnetic results from earlier studies at Steens Mountain with those from three newly studied sections of Oregon Plateau flood basalts at Catlow Peak and Poker Jim Ridge 70–90 km to the southeast and west, respectively, we provide support for this interpretation with the most detailed account of a magnetic field reversal yet observed in volcanic rocks. Forty-five new distinguishable transitional (T) directions together with 30 earlier ones reveal a much more complex and detailed record of the 16.7 Ma reversed (R)-to-normal (N) polarity transition that marks the end of Chron C5Cr. Compared to the earlier R-T-N-T-N reversal record, the new record can be described as R-T-N-T-N-T-R-T-N. The composite record confirms earlier features, adds new west and up directions and an entire large N-T-R-T segment to the path, and fills in directions on the path between earlier directional jumps. Persistent virtual geomagnetic pole (VGP) clusters and separate VGPs have a preference for previously described longitudinal bands from transition study compilations, which suggests the presence of features at the core–mantle boundary that influence the flow of core fluid and distribution of magnetic flux. Overall the record is consistent with the generalization that VGP paths vary greatly from reversal to reversal and depend on the location of the observer. Rates of secular variation confirm that the flows comprising these sections were erupted rapidly, with maximum rates estimated to be 85–120 m ka−1 at Catlow and 130–195 m ka−1 at Poker Jim South. Paleomagnetic poles from other studies are combined with 32 non-transitional poles found here to give a clockwise rotation of the Oregon Plateau of 11.4°± 5.6° with respect to the younger Columbia River Basalt Group flows to the north and 14.5°± 4.6° with respect

  14. Comparison of 3-Factor Prothrombin Complex Concentrate and Low-Dose Recombinant Factor VIIa for Warfarin Reversal

    OpenAIRE

    Chapman, Scott A; Irwin, Eric D; Abou-Karam, Nada M; Rupnow, Nichole M; Hutson, Katherine E; Vespa, Jeffrey; Roach, Robert M

    2014-01-01

    Introduction Prothrombin complex concentrate (PCC) and recombinant Factor VIIa (rFVIIa) have been used for emergent reversal of warfarin anticoagulation. Few clinical studies have compared these agents in warfarin reversal. We compared warfarin reversal in patients who received either 3 factor PCC (PCC3) or low-dose rFVIIa (LDrFVIIa) for reversal of warfarin anticoagulation. Methods Data were collected from medical charts of patients who received at least one dose of PCC3 (20 units/kg) or LDr...

  15. The impact of chemical cleaning on separation efficiency and properties of reverse osmosis membrane

    KAUST Repository

    Baatiyyah, Hani

    2018-04-01

    One of most major concerns from both cost-effective and technical point of view in membrane process industry is membrane cleaning. The aim of the project was to investigate the variations in membrane surface properties and separation efficiency of reverse osmosis membrane. Compativtive analysis have to be performed on four RO membrane before and after exposing the virgin membrane into chemical cleaning to identify and analysis the impact of the chemical cleaning on the performance of RO membrane. Commerical chemical cleaning used in this project were caustic and acidic cleaning agent. The project’s aim is the investigation of simulation software’s precision for the four membranes performance projection at different conditions of the feed water. The assessment of the membranes performance was done in the Innovation Cluster at pilot plant that was industrial in size. The main commercial elements used were the thin-film composite membranes with a spiral-wound of 8-inch polyamide. Ultrafiltration (UF) and seawater RO membrane pretreatment process was done for the red sea sourced feed water. A pressure vessel dimensioned at 8-inch was operated in conjunction with an individual element at 8 -20 m3/hr feed flow rate, with an 8 to 12 % recovery and an average 35,000-42,000 mg/L of total dissolved solids (TDS) composition for the feed water. To achieve the project’s aim in assessing the membranes, three phase experimental stages were completed. The membranes performance was assessed in terms of their water flux, salt rejection, boron rejection, bicarbonate rejection and permeate quality. In addition, the membrane surfaces were characterized after exposing the fresh membranes with a chemical cleaning reagent. The experimental results showed an increase in both permeate flow and salt passage for all studied elements. The changes in the membranes performance were systematically explained based on the changes in the charge density and chemical structure of the membranes

  16. Uranium complexes with macrosyclic polyethers. Synthesis and structural chemical analysis

    International Nuclear Information System (INIS)

    Elbasyouny, A.

    1983-01-01

    This dissertation reports about studies on the chemical coordination behaviour of uranium of oxidation stages IV and VI with regard to twelve different macrocyclic ligands. For the preparation of the complexes, for every system a different method has been developed. The elementary analysis of the various complexes including the uranium had been done by X-ray fluorescence analysis, and the structural characterization proceeded via vibrational, uv-vis and emission spectroscopy as well as 1 H-NMR and 13 C-spin-lattice relaxation time studies. Conformational analysis of the polyethers used allowed the structural changes in the complexes to be observed. The structural analysis of the hydrous uranium VI crown ether complexes yielded information of characteristic features of these types of complexes. The first coordination sphere of the uranyl ion with covalently bonded anion remains unchanged. As to the water content, there is a certain range. Depending upon the solvent used, the complexes have two or four H 2 O molecules per formula unit. (orig./EF) [de

  17. Chemical bonding of hydrogen molecules to transition metal complexes

    International Nuclear Information System (INIS)

    Kubas, G.J.

    1990-01-01

    The complex W(CO) 3 (PR 3 ) 2 (H 2 ) (CO = carbonyl; PR 3 = organophosphine) was prepared and was found to be a stable crystalline solid under ambient conditions from which the hydrogen can be reversibly removed in vacuum or under an inert atmosphere. The weakly bonded H 2 exchanges easily with D 2 . This complex represents the first stable compound containing intermolecular interaction of a sigma-bond (H-H) with a metal. The primary interaction is reported to be donation of electron density from the H 2 bonding electron pair to a vacant metal d-orbital. A series of complexes of molybdenum of the type Mo(CO)(H 2 )(R 2 PCH 2 CH 2 PR 2 ) 2 were prepared by varying the organophosphine substitutent to demonstrate that it is possible to bond either dihydrogen or dihydride by adjusting the electron-donating properties of the co-ligands. Results of infrared and NMR spectroscopic studies are reported. 20 refs., 5 fig

  18. Locating the source of diffusion in complex networks by time-reversal backward spreading

    Science.gov (United States)

    Shen, Zhesi; Cao, Shinan; Wang, Wen-Xu; Di, Zengru; Stanley, H. Eugene

    2016-03-01

    Locating the source that triggers a dynamical process is a fundamental but challenging problem in complex networks, ranging from epidemic spreading in society and on the Internet to cancer metastasis in the human body. An accurate localization of the source is inherently limited by our ability to simultaneously access the information of all nodes in a large-scale complex network. This thus raises two critical questions: how do we locate the source from incomplete information and can we achieve full localization of sources at any possible location from a given set of observable nodes. Here we develop a time-reversal backward spreading algorithm to locate the source of a diffusion-like process efficiently and propose a general locatability condition. We test the algorithm by employing epidemic spreading and consensus dynamics as typical dynamical processes and apply it to the H1N1 pandemic in China. We find that the sources can be precisely located in arbitrary networks insofar as the locatability condition is assured. Our tools greatly improve our ability to locate the source of diffusion in complex networks based on limited accessibility of nodal information. Moreover, they have implications for controlling a variety of dynamical processes taking place on complex networks, such as inhibiting epidemics, slowing the spread of rumors, pollution control, and environmental protection.

  19. Industrial hygiene survey. IMC, Phosphate Chemical Complex, New Wales, Florida

    International Nuclear Information System (INIS)

    Stephenson, F.; Cassady, M.

    1977-10-01

    An industrial hygiene survey was conducted by NIOSH at IMC Phosphate Chemical Complex, New Wales, Florida, on June 7-11, 1976, as part of a study of the phosphate industry. Phosphate fertilizer manufacturing, the plant, and the medical, safety, and industrial hygiene programs are described. During the study 8-hour time weighted averages were determined for exposure to arsenic, cadmium, chromium, vanadium, phosphoric acid, and sulfuric acid for workers involved in cleaning out phosphoric acid reactor vessels. General area samples were collected for fluorides, radon, and uranium. Several samples were above the NIOSH recommended levels for arsenic and chromium

  20. Reversible dihydrogen activation and hydride transfer by a uranium nitride complex

    Energy Technology Data Exchange (ETDEWEB)

    Falcone, Marta; Poon, Lok Nga; Fadaei Tirani, Farzaneh; Mazzanti, Marinella [Institut des Sciences et Ingenierie Chimiques, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne (Switzerland)

    2018-03-26

    Cleavage of dihydrogen is an important step in the industrial and enzymatic transformation of N{sub 2} into ammonia. The reversible cleavage of dihydrogen was achieved under mild conditions (room temperature and 1 atmosphere of H{sub 2}) by the molecular uranium nitride complex, [Cs{U(OSi(O"tBu)_3)_3}{sub 2}(μ-N)], leading to a rare hydride-imide bridged diuranium(IV) complex, [Cs{U(OSi(O"tBu)_3)_3}{sub 2}(μ-H)(μ-NH)], that slowly releases H{sub 2} under vacuum. This complex is highly reactive and quickly transfers hydride to acetonitrile and carbon dioxide at room temperature, affording the ketimide- and formate-bridged U{sup IV} species [Cs{U(OSi(O"tBu)_3)_3}{sub 2}(μ-NH)(μ-CH{sub 3}CHN)] and [Cs{U(OSi(O"tBu)_3)_3}{sub 2}(μ-HCOO)(μ-NHCOO)]. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Intracytoplasmic maturation of the human immunodeficiency virus type 1 reverse transcription complexes determines their capacity to integrate into chromatin

    Directory of Open Access Journals (Sweden)

    Kashanchi Fatah

    2006-01-01

    Full Text Available Abstract Background The early events of the HIV-1 life cycle include entry of the viral core into target cell, assembly of the reverse transcription complex (RTCs performing reverse transcription, its transformation into integration-competent complexes called pre-integration complexes (PICs, trafficking of complexes into the nucleus, and finally integration of the viral DNA into chromatin. Molecular details and temporal organization of these processes remain among the least investigated and most controversial problems in the biology of HIV. Results To quantitatively evaluate maturation and nuclear translocation of the HIV-1 RTCs, nucleoprotein complexes isolated from the nucleus (nRTC and cytoplasm (cRTC of HeLa cells infected with MLV Env-pseudotyped HIV-1 were analyzed by real-time PCR. While most complexes completed reverse transcription in the cytoplasm, some got into the nucleus before completing DNA synthesis. The HIV-specific RNA complexes could get into the nucleus when reverse transcription was blocked by reverse transcriptase inhibitor, although nuclear import of RNA complexes was less efficient than of DNA-containing RTCs. Analysis of the RTC nuclear import in synchronized cells infected in the G2/M phase of the cell cycle showed enrichment in the nuclei of RTCs containing incomplete HIV-1 DNA compared to non-synchronized cells, where RTCs with complete reverse transcripts prevailed. Immunoprecipitation assays identified viral proteins IN, Vpr, MA, and cellular Ini1 and PML associated with both cRTCs and nRTCs, whereas CA was detected only in cRTCs and RT was diminished in nRTCs. Cytoplasmic maturation of the complexes was associated with increased immunoreactivity with anti-Vpr and anti-IN antibodies, and decreased reactivity with antibodies to RT. Both cRTCs and nRTCs carried out endogenous reverse transcription reaction in vitro. In contrast to cRTCs, in vitro completion of reverse transcription in nRTCs did not increase their

  2. Post-Digestion Liquor Treatment in the Method Combining Chemical Precipitation with Reverse Osmosis

    Directory of Open Access Journals (Sweden)

    Kuglarz Mariusz

    2014-12-01

    Full Text Available The aim of the study was to develop an effective treatment of post-digestion liquors highly-loaded with biogenic and organic substances. The scope of the research project encompassed: mesophilic anaerobic digestion of waste activated sludge (WAS as well as the treatment of post-digestion liquors, coming from the most appropriate HRT value of 25 days, in the process of ammonium magnesium phosphate (struvite precipitation targeted at ammonia nitrogen binding and a subsequent reverse osmosis (RO process. It was established that the method combining chemical precipitation and high-pressure filtration ensures a high degree of contaminants removal allowing for a direct release of treated liquors into the natural reservoir. However, in order to decrease the residual NH4+ concentration (6.1 mg NH4+/dm3 in the purified post-digestion liquors below the level allowing for a direct release to the natural reservoir, it turned out to be necessary to apply increased molar ratio of magnesium and phosphates (Mg:NH4+: PO43-= 1.5:1:1.5.

  3. Reversible solid oxide fuel cells (R-SOFCs) with chemically stable proton-conducting oxides

    KAUST Repository

    Bi, Lei

    2015-07-01

    Proton-conducting oxides offer a promising way of lowering the working temperature of solid oxide cells to the intermediate temperate range (500 to 700. °C) due to their better ionic conductivity. In addition, the application of proton-conducting oxides in both solid oxide fuel cells (SOFCs) and sold oxide electrolysis cells (SOECs) provides unique advantages compared with the use of conventional oxygen-ion conducting conductors, including the formation of water at the air electrode site. Since the discovery of proton conduction in some oxides about 30. years ago, the development of proton-conducting oxides in SOFCs and SOECs (the reverse mode of SOFCs) has gained increased attention. This paper briefly summarizes the development in the recent years of R-SOFCs with proton-conducting electrolytes, focusing on discussing the importance of adopting chemically stable materials in both fuel cell and electrolysis modes. The development of electrode materials for proton-conducting R-SOFCs is also discussed. © 2015 Elsevier B.V.

  4. Performance and cost of energy transport and storage systems for dish applications using reversible chemical reactions

    Science.gov (United States)

    Schredder, J. M.; Fujita, T.

    1984-01-01

    The use of reversible chemical reactions for energy transport and storage for parabolic dish networks is considered. Performance and cost characteristics are estimated for systems using three reactions (sulfur-trioxide decomposition, steam reforming of methane, and carbon-dioxide reforming of methane). Systems are considered with and without storage, and in several energy-delivery configurations that give different profiles of energy delivered versus temperature. Cost estimates are derived assuming the use of metal components and of advanced ceramics. (The latter reduces the costs by three- to five-fold). The process that led to the selection of the three reactions is described, and the effects of varying temperatures, pressures, and heat exchanger sizes are addressed. A state-of-the-art survey was performed as part of this study. As a result of this survey, it appears that formidable technical risks exist for any attempt to implement the systems analyzed in this study, especially in the area of reactor design and performance. The behavior of all components and complete systems under thermal energy transients is very poorly understood. This study indicates that thermochemical storage systems that store reactants as liquids have efficiencies below 60%, which is in agreement with the findings of earlier investigators.

  5. Nanosized complexation assemblies housed inside reverse micelles churn out monocytic delivery cores for bendamustine hydrochloride.

    Science.gov (United States)

    Singh, Yuvraj; Chandrashekhar, Anumandla; Meher, Jaya Gopal; Durga Rao Viswanadham, K K; Pawar, Vivek K; Raval, Kavit; Sharma, Komal; Singh, Pankaj K; Kumar, Animesh; Chourasia, Manish K

    2017-04-01

    We explore a plausible method of targeting bendamustine hydrochloride (BM) to circulatory monocytes by exploiting their intrinsic endocytic/phagocytic capability. We do so by complexation of sodium alginate and chitosan inside dioctyl sulfo succinate sodium (AOT) reverse micelles to form bendamustine hydrochloride loaded nanoparticles (CANPs). Dynamic light scattering, electrophoretic mobility and UV spectroscopy were used to detail intra-micellar complexation dynamics and to prove that drug was co-captured during interaction of carbohydrate polymers. A fluorescent conjugate of drug (RBM) was used to trace its intracellular fate after its loading into nanoparticles. CANPs were sized below 150nm, had 75% drug entrapment and negative zeta potential (-30mV). Confocal microscopy demonstrated that developed chitosan alginate nanoparticles had the unique capability to carry BM specifically to its site of action. Quantitative and mechanism based cell uptake studies revealed that monocytes had voracious capacity to internalize CANPs via simultaneous scavenger receptor based endocytic and phagocytic mechanism. Comparative in vitro pharmacokinetic studies revealed obtainment of significantly greater intracellular drug levels when cells were treated with CANPs. This caused reduction in IC 50 (22.5±2.1μg/mL), enhancement in G 2 M cell cycle arrest, greater intracellular reactive oxygen species generation, and increased apopotic potential of bendamustine hydrochloride in THP-1 cells. Selective monocytic targeting of bendamustine hydrochloride using carbohydrate constructs can prove advantageous in case of leukemic disorders displaying overabundance of such cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Characterization of active reverse transcriptase and nucleoprotein complexes of the yeast retrotransposon Ty3 in vitro.

    Science.gov (United States)

    Cristofari, G; Gabus, C; Ficheux, D; Bona, M; Le Grice, S F; Darlix, J L

    1999-12-17

    Human immunodeficiency virus (HIV) and the distantly related yeast Ty3 retrotransposon encode reverse transcriptase (RT) and a nucleic acid-binding protein designated nucleocapsid protein (NCp) with either one or two zinc fingers, required for HIV-1 replication and Ty3 transposition, respectively. In vitro binding of HIV-1 NCp7 to viral 5' RNA and primer tRNA(3)(Lys) catalyzes formation of nucleoprotein complexes resembling the virion nucleocapsid. Nucleocapsid complex formation functions in viral RNA dimerization and tRNA annealing to the primer binding site (PBS). RT is recruited in these nucleoprotein complexes and synthesizes minus-strand cDNA initiated at the PBS. Recent results on yeast Ty3 have shown that the homologous NCp9 promotes annealing of primer tRNA(i)(Met) to a 5'-3' bipartite PBS, allowing RNA:tRNA dimer formation and initiation of cDNA synthesis at the 5' PBS (). To compare specific cDNA synthesis in a retrotransposon and HIV-1, we have established a Ty3 model system comprising Ty3 RNA with the 5'-3' PBS, primer tRNA(i)(Met), NCp9, and for the first time, highly purified Ty3 RT. Here we report that Ty3 RT is as active as retroviral HIV-1 or murine leukemia virus RT using a synthetic template-primer system. Moreover, and in contrast to what was found with retroviral RTs, retrotransposon Ty3 RT was unable to direct cDNA synthesis by self-priming. We also show that Ty3 nucleoprotein complexes were formed in vitro and that the N terminus of NCp9, but not the zinc finger, is required for complex formation, tRNA annealing to the PBS, RNA dimerization, and primer tRNA-directed cDNA synthesis by Ty3 RT. These results indicate that NCp9 chaperones bona fide cDNA synthesis by RT in the yeast Ty3 retrotransposon, as illustrated for NCp7 in HIV-1, reinforcing the notion that Ty3 NCp9 is an ancestor of HIV-1 NCp7.

  7. Smelling in chemically complex environments: an optofluidic Bragg fiber array for differentiation of methanol adulterated beverages.

    Science.gov (United States)

    Yildirim, Adem; Ozturk, Fahri Emre; Bayindir, Mehmet

    2013-07-02

    A novel optoelectronic nose for analysis of alcohols (ethanol and methanol) in chemically complex environments is reported. The cross-responsive sensing unit of the optoelectronic nose is an array of three distinct hollow-core infrared transmitting photonic band gap fibers, which transmit a specific band of IR light depending on their Bragg mirror structures. The presence of alcohol molecules in the optofluidic core quenches the fiber transmissions if there is an absorption band of the analyte overlapping with the transmission band of the fiber; otherwise they remain unchanged. The cumulative response data of the fiber array enables rapid, reversible, and accurate discrimination of alcohols in chemically complex backgrounds such as beer and fruit juice. In addition, we observed that humidity of the environment has no effect on the response matrix of the optoelectronic nose, which is rarely achieved in gas-sensing applications. Consequently, it can be reliably used in virtually any environment without precalibration for humidity or drying the analytes. Besides the discussed application in counterfeit alcoholic beverages, with its superior sensor parameters, this novel concept proves to be a promising contender for many other applications including food quality control, environmental monitoring, and breath analysis for disease diagnostics.

  8. DNA-directed control of enzyme-inhibitor complex formation: a modular approach to reversibly switch enzyme activity

    NARCIS (Netherlands)

    Janssen, B.M.G.; Engelen, W.; Merkx, M.

    2015-01-01

    DNA-templated reversible assembly of an enzyme–inhibitor complex is presented as a new and highly modular approach to control enzyme activity. TEM1-ß-lactamase and its inhibitor protein BLIP were conjugated to different oligonucleotides, resulting in enzyme inhibition in the presence of template

  9. Mechanistic Aspects of the Reversible Binding of SO2 on Arylplatinum Complexes: Experimental and ab Initio Studies

    NARCIS (Netherlands)

    Koten, G. van; Albrecht, M.A.; Gossage, R.A.; Frey, H.; Ehlers, A.W.; Baerends, E.J.; Merbach, A.E.

    2001-01-01

    The detailed mechanism of the reversible binding and fast exchange of SO2 on the organoplatinum(II) complex [PtI(NCN)], 1, has been studied experimentally in solution (C2F4Br2) using low-temperature NMR spectroscopy and theoretically by ab initio calculations. Direct bonding of SO2 and formation of

  10. Fixed Versus Variable Dosing of 4-factor Prothrombin Complex Concentrate for Emergent Warfarin Reversal

    Science.gov (United States)

    2018-04-06

    Acute Bleeding on Long-Term Anticoagulation Therapy; Hemorrhage; Significant Bleeding in Patients With a Coagulopathy (Prolonged Thrombin Time); Urgent Reversal of Vitamin K Antagonist (VKA) Anticoagulation

  11. Fouling of Seawater Reverse Osmosis (SWRO) Membrane: Chemical and Microbiological Characterization

    KAUST Repository

    Khan, Muhammad T.

    2013-01-01

    In spite of abundant water resources, world is suffering from the scarcity of usable water. Seawater Reverse Osmosis (SWRO) desalination technology using polymeric membranes has been recognized as a key solution to water scarcity problem. However

  12. Fouling of Seawater Reverse Osmosis (SWRO) Membrane: Chemical and Microbiological Characterization

    KAUST Repository

    Khan, Muhammad T.

    2013-12-01

    In spite of abundant water resources, world is suffering from the scarcity of usable water. Seawater Reverse Osmosis (SWRO) desalination technology using polymeric membranes has been recognized as a key solution to water scarcity problem. However, economic sustainability of this advanced technology is adversely impacted by the membrane fouling problem. Fouling of RO membranes is a highly studied phenomenon. However, literature is found to be lacking a detailed study on kinetic and dynamic aspects of SWRO membrane fouling. The factors that impact the fouling dynamics, i.e., pretreatment and water quality were also not adequately studied at full–scale of operation. Our experimental protocol was designed to systematically explore these fouling aspects with the objective to improve the understanding of SWRO membrane fouling mechanisms. An approach with multiple analytical techniques was developed for fouling characterization. In addition to the fouling layer characterization, feed water quality was also analysed to assess its fouling potential. Study of SWRO membrane fouling dynamics and kinetics revealed variations in relative abundance of chemical and microbial constituents of the fouling layer, over operating time. Aromatic substances, most likely humic–like substances, were observed at relatively high abundance in the initial fouling layer, followed by progressive increase in relative abundances of proteins and polysaccharides. Microbial population grown on all membranes was dominated by specific groups/species belonging to different classes of Proteobacteria phylum; however, similar to abiotic foulant, their relative abundance also changed with the biofilm age and with the position of membrane element in RO vessel. Our results demonstrated that source water quality can significantly impact the RO membrane fouling scenarios. Moreover, the major role of chlorination in the SWRO membrane fouling was highlighted. It was found that intermittent mode of chlorination

  13. Three- versus four-factor prothrombin complex concentrate for the reversal of warfarin-induced bleeding

    Science.gov (United States)

    Holt, Tara; Taylor, Scott; Abraham, Prasad; Mcmillian, Wesley; Harris, Serena; Curtis, James; Elder, Tai

    2018-01-01

    Objective: The objective of this study was to evaluate the effectiveness of 3-factor prothrombin complex concentrate (3F-PCC) compared to 4-factor PCC (4F-PCC) in warfarin-associated bleeding. Methods: This multicenter, retrospective, cohort study analyzed data from patients admitted between May 2011 and October 2014 who received PCC for warfarin-associated bleeding. The primary outcome was the rate of international normalized ratio (INR) normalization, defined as an INR ≤1.3, after administration of 3F-PCC compared to 4F-PCC. Other variables of interest included the incidence of additional reversal agents, new thromboembolic events, and mortality. Results: A total of 134 patients were included in the analysis. The average dose of PCC administered was 24.6 ± 9.3 units/kg versus 36.3 ± 12.8 units/kg in the 3F-PCC and 4F-PCC groups, respectively, P < 0.001. Baseline INR in the 3F-PCC and 4F-PCC groups was 3.61 ± 2.3 and 6.87 ± 2.3, respectively P < 0.001. 4F-PCC had a higher rate of INR normalization at first INR check post-PCC administration compared to 3F-PCC (84.2% vs. 51.9%, P = 0.0001). Thromboembolic events, intensive care unit and hospital length of stay, and mortality were similar among both groups. Conclusion: The use of 4F-PCC leads to a more significant reduction in INR compared to 3F-PCC though no difference in mortality or length of stay was observed. Thromboembolism rates were similar among both groups. PMID:29619338

  14. Chemical speciation of L-glutamine complexes with Co(II), Ni(II) and ...

    African Journals Online (AJOL)

    The trend in the variation of stability constants of the complexes with mole fraction of the surfactant is attributed to the compartmentalization of complexation equilibria. Distribution of species and effect of influential parameters on chemical speciation have also been presented. KEY WORDS: Chemical speciation, complex ...

  15. Features of E-Z-photoisomerization reversible reaction of 4-styrylpyridine crown-containing complexes with different cations

    International Nuclear Information System (INIS)

    Fedorov, Yu.V.; Shepel', N.Eh.; Chernikova, E.Yu.; Fedorova, O.A.; Gulakova, E.N.; Avakyan, V.G.; Jonushauskas, G.

    2008-01-01

    E-Z-Photoisomerization reversible reaction of crown-containing 4-styrylpyridine in the presence of alkali metal perchlorates (Ca 2+ , Mg 2+ , Ba 2+ ) gifted in the formation of complexes with crown-ether fragments, as well as heavy metal perchlorates (Hg 2+ , Cd 2+ ) gifted in the coordination with nitrogen atom of heterocyclic residuum has been studied. Effect of complexing on the photoisomerization is determined by electron spectroscopy and NMR 1 H, structures of the formed Z-isomers are established. The possibility of the E-Z-isomerization control with the use of supramolecular complexing is confirmed by the investigations [ru

  16. The First Example of a Nitrile Hydratase Model Complex that Reversibly Binds Nitriles

    Science.gov (United States)

    Shearer, Jason; Jackson, Henry L.; Schweitzer, Dirk; Rittenberg, Durrell K.; Leavy, Tanya M.; Kaminsky, Werner; Scarrow, Robert C.; Kovacs, Julie A.

    2015-01-01

    Nitrile hydratase (NHase) is an iron-containing metalloenzyme that converts nitriles to amides. The mechanism by which this biochemical reaction occurs is unknown. One mechanism that has been proposed involves nucleophilic attack of an Fe-bound nitrile by water (or hydroxide). Reported herein is a five-coordinate model compound ([FeIII(S2Me2N3(Et,Pr))]+) containing Fe(III) in an environment resembling that of NHase, which reversibly binds a variety of nitriles, alcohols, amines, and thiocyanate. XAS shows that five-coordinate [FeIII(S2Me2N3(Et,Pr))]+ reacts with both methanol and acetonitrile to afford a six-coordinate solvent-bound complex. Competitive binding studies demonstrate that MeCN preferentially binds over ROH, suggesting that nitriles would be capable of displacing the H2O coordinated to the iron site of NHase. Thermodynamic parameters were determined for acetonitrile (ΔH = −6.2(±0.2) kcal/mol, ΔS = −29.4(±0.8) eu), benzonitrile (−4.2(±0.6) kcal/mol, ΔS = −18(±3) eu), and pyridine (ΔH = −8(±1) kcal/mol, ΔS = −41(±6) eu) binding to [FeIII(S2Me2N3(Et,Pr))]+ using variable-temperature electronic absorption spectroscopy. Ligand exchange kinetics were examined for acetonitrile, iso-propylnitrile, benzonitrile, and 4-tert-butylpyridine using 13C NMR line-broadening analysis, at a variety of temperatures. Activation parameters for ligand exchange were determined to be ΔH‡ = 7.1(±0.8) kcal/mol, ΔS‡ = −10(±1) eu (acetonitrile), ΔH‡ = 5.4(±0.6) kcal/mol, ΔS‡ = −17(±2) eu (iso-propionitrile), ΔH‡ = 4.9(±0.8) kcal/mol, ΔS‡ = −20(±3) eu (benzonitrile), and ΔH‡ = 4.7(±1.4) kcal/mol ΔS‡ = −18(±2) eu (4-tert-butylpyridine). The thermodynamic parameters for pyridine binding to a related complex, [FeIII(S2Me2N3(Pr,Pr))]+ (ΔH = −5.9(±0.8) kcal/mol, ΔS = −24(±3) eu), are also reported, as well as kinetic parameters for 4-tert-butylpyridine exchange (ΔH‡ = 3.1(±0.8) kcal/mol, ΔS‡)−25(±3) eu

  17. Total chemical synthesis of histones and their analogs, assisted by native chemical ligation and palladium complexes.

    Science.gov (United States)

    Maity, Suman Kumar; Jbara, Muhammad; Mann, Guy; Kamnesky, Guy; Brik, Ashraf

    2017-11-01

    Chemical synthesis of histones allows precise control of the installation of post-translational modifications via the coupling of derivatized amino acids. Shortcomings of other approaches for obtaining modified histones for epigenetic studies include heterogeneity of the obtained product and difficulties in incorporating multiple modifications on the same histone. In this protocol, unprotected peptide fragments are prepared by Fmoc solid-phase synthesis and coupled in aqueous buffers via native chemical ligation (NCL; in NCL, a peptide bond is formed between a peptide with an N-terminal Cys and another peptide having a C-terminal thioester). This task is challenging, with obstacles relating to the preparation and ligation of hydrophobic peptides, as well as the requirement for multiple purification steps due to protecting-group manipulations during the polypeptide assembly process. To address this, our approach uses an easily removable solubilizing tag for the synthesis and ligation of hydrophobic peptides, as well as a more efficient and better-yielding method to remove Cys-protecting groups that uses palladium chemistry (specifically [Pd(allyl)Cl] 2 and PdCl 2 complexes). The utility of this approach is demonstrated in the syntheses of ubiquitinated H2B at Lys34, phosphorylated H2A at Tyr57 and unmodified H4. Each of these analogs can be prepared in milligram quantities within ∼20-30 d.

  18. Analysis of mechanism of complex chemical reaction taking radiation chemical purification of gases from impurities as an example

    International Nuclear Information System (INIS)

    Gerasimov, G.Ya.; Makarov, V.N.

    1997-01-01

    Algorithm of selecting optimal mechanism of complex chemical reaction, enabling to reduce the number of its stages, is suggested. Main steps of constructing the kinetic model of the medium are considered, taking the radiation chemical purification (using fast electron radiation) of gases (N 2 , CO 2 , O 2 and others) from impurities as an example. 17 refs., 3 figs., 2 tabs

  19. Chemical solution deposition techniques for epitaxial growth of complex oxides

    NARCIS (Netherlands)

    ten Elshof, Johan E.; Koster, G.; Huijben, Mark; Rijnders, G.

    2015-01-01

    The chemical solution deposition (CSD) process is a wet-chemical process that is employed to fabricate a wide variety of amorphous and crystalline oxide thin films. This chapter describes the typical steps in a CSD process and their influence on the final microstructure and properties of films, and

  20. Algorithmic Complexity and Reprogrammability of Chemical Structure Networks

    KAUST Repository

    Zenil, Hector; Kiani, Narsis A.; Shang, Ming-mei; Tegner, Jesper

    2018-01-01

    Here we address the challenge of profiling causal properties and tracking the transformation of chemical compounds from an algorithmic perspective. We explore the potential of applying a computational interventional calculus based on the principles of algorithmic probability to chemical structure networks. We profile the sensitivity of the elements and covalent bonds in a chemical structure network algorithmically, asking whether reprogrammability affords information about thermodynamic and chemical processes involved in the transformation of different compound classes. We arrive at numerical results suggesting a correspondence between some physical, structural and functional properties. Our methods are capable of separating chemical classes that reflect functional and natural differences without considering any information about atomic and molecular properties. We conclude that these methods, with their links to chemoinformatics via algorithmic, probability hold promise for future research.

  1. Algorithmic Complexity and Reprogrammability of Chemical Structure Networks

    KAUST Repository

    Zenil, Hector

    2018-04-02

    Here we address the challenge of profiling causal properties and tracking the transformation of chemical compounds from an algorithmic perspective. We explore the potential of applying a computational interventional calculus based on the principles of algorithmic probability to chemical structure networks. We profile the sensitivity of the elements and covalent bonds in a chemical structure network algorithmically, asking whether reprogrammability affords information about thermodynamic and chemical processes involved in the transformation of different compound classes. We arrive at numerical results suggesting a correspondence between some physical, structural and functional properties. Our methods are capable of separating chemical classes that reflect functional and natural differences without considering any information about atomic and molecular properties. We conclude that these methods, with their links to chemoinformatics via algorithmic, probability hold promise for future research.

  2. Algorithmic Complexity and Reprogrammability of Chemical Structure Networks

    KAUST Repository

    Zenil, Hector

    2018-02-16

    Here we address the challenge of profiling causal properties and tracking the transformation of chemical compounds from an algorithmic perspective. We explore the potential of applying a computational interventional calculus based on the principles of algorithmic probability to chemical structure networks. We profile the sensitivity of the elements and covalent bonds in a chemical structure network algorithmically, asking whether reprogrammability affords information about thermodynamic and chemical processes involved in the transformation of different compound classes. We arrive at numerical results suggesting a correspondence between some physical, structural and functional properties. Our methods are capable of separating chemical classes that reflect functional and natural differences without considering any information about atomic and molecular properties. We conclude that these methods, with their links to chemoinformatics via algorithmic, probability hold promise for future research.

  3. Quantum chemical investigation of levofloxacin-boron complexes: A computational approach

    Science.gov (United States)

    Sayin, Koray; Karakaş, Duran

    2018-04-01

    Quantum chemical calculations are performed over some boron complexes with levofloxacin. Boron complex with fluorine atoms are optimized at three different methods (HF, B3LYP and M062X) with 6-31 + G(d) basis set. The best level is determined as M062X/6-31 + G(d) by comparison of experimental and calculated results of complex (1). The other complexes are optimized by using the best level. Structural properties, IR and NMR spectrum are examined in detail. Biological activities of mentioned complexes are investigated by some quantum chemical descriptors and molecular docking analyses. As a result, biological activities of complex (2) and (4) are close to each other and higher than those of other complexes. Additionally, NLO properties of mentioned complexes are investigated by some quantum chemical parameters. It is found that complex (3) is the best candidate for NLO applications.

  4. Chemical evaluation and treatment of ground water for university town Peshawar, Pakistan by reverse osmosis technology

    International Nuclear Information System (INIS)

    Saddique, M.; Gilani, S.N.; Ishaq, M.; Gul, F.

    2012-01-01

    Present study is focused on the ground water treatment for the University Town Peshawar by reverse osmosis technology, based on the principle of reverse-osmosis pure water and ultra pure water filtration. Water collected from three locations was analyzed. The results showed that the first two water samples were neutral having pH 7.09 and 7.16 comparable with the range (6.50-8.50), while the pH for the water sample getting purified and passed from RO process was 5.33 i.e. slightly acidic. The ionic content of the water sample was low, whereas the conductivity ranged from 624-634 micro S/cm for the first two samples and reduced to 1.37 muS/cm. The parameters investigated are below the safety baseline levels of the national and international standards with the exception of Pb. (author)

  5. Reversible chemical delithiation/lithiation of LiFePO4: towards a redox flow lithium-ion battery.

    Science.gov (United States)

    Huang, Qizhao; Li, Hong; Grätzel, Michael; Wang, Qing

    2013-02-14

    Reversible chemical delithiation/lithiation of LiFePO(4) was successfully demonstrated using ferrocene derivatives, based on which a novel energy storage system--the redox flow lithium-ion battery (RFLB), was devised by integrating the operation flexibility of a redox flow battery and high energy density of a lithium-ion battery. Distinct from the recent semi-solid lithium rechargeable flow battery, the energy storage materials of RFLB stored in separate energy tanks remain stationary upon operation, giving us a fresh perspective on building large-scale energy storage systems with higher energy density and improved safety.

  6. Chemical effects of nuclear transformations in molybdenum complexes

    International Nuclear Information System (INIS)

    Millan S, S.A.

    1977-01-01

    The Szilard-Chalmers effect was studied in the complexes: tetraacetatedimolybdenum(II), tetrabenzoatedimolybdenum(II), benzenetricarbonylmolybdenym(0). The results we obtained in the measurement of the Szilard-Chalmers effect on the studied complexes imply some influence of the structure in the molecular fragmentation, or the conservation of the links molybdenum-ligands. (author)

  7. Health risk assessment of chemical pollutants in a petrochemical complex

    Directory of Open Access Journals (Sweden)

    F Golbabaie

    2012-12-01

    Full Text Available   Background and Aims: workers in petrochemical industries are exposed to various contaminants and are facing to serious hazards, therefore a comprehensive risk assessment program for identification of hazardous chemicals that affect human health and also determination of hazardous tasks and processes is necessary.     Methods : This descriptive cross-sectional study was conducted in three stages. First stage consisted of identifying hazardous chemicals and determination of chemicals risk ratio, the second stage included the evaluation of worker's exposure to hazardous chemicals, and the third stage was estimating the relative risk of blood cancer caused by exposure to benzene through epidemiological studies.     Results: With regard to risk assessment method, 40 chemicals were identified in this Petrochemical Company. Among them, Benzene introduced as the most hazardous chemical. The results of the second stage showed that site man workers in noon shift work and in aromatic site with mean exposure 4.29 ppm had the highest exposure to benzene. The results of estimated leukemia relative risk stage in benzene exposure, the highest relative risk in workers related to site man workers in aromatic units with cumulative benzene exposure of 4.149 ppm. Years that obtained the relative risk of 2.3. The statistical test results showed that the relationship between worker's exposure to benzene and their job was significant(p<0/001     Conclusion : This study showed that benzene with a risk ratio of 4.5 -5 have 5th rank in risk levels and this indicates that preventative actions regarding to this hazardous and carcinogenic chemical must be started as soon as possible.

  8. Physico-chemical studies of some aminobenzoic acid hydrazide complexes

    Directory of Open Access Journals (Sweden)

    S. ABD EL HALEEM

    2004-04-01

    Full Text Available The stability constants and related thermodynamic functions characterizing the formation of divalent Ni, Cu, Zn, Cd and Hg complexes with o- and p-aminobenzoic acid hydrazide were determined potentiometrically at different temperatures. The formations of the complexes are endothermic processes. The formed bonds are mainly electrostatic. Conductometric titration was carried out to determine the stoichiometry and stability of the formed complexes. The structures of complexes were characterized by their IR, 1H-NMR and 13C-NMR spectra, as well as X-ray diffractograms. The coordination process takes place through the carbonyl group and the terminal hydrazinic amino group. The thermal stability of the complexes was followed in the temperature range 20–600ºC.

  9. Acoustic wave focusing in complex media using Nonlinear Time Reversal coded signal processing

    Czech Academy of Sciences Publication Activity Database

    Dos Santos, S.; Dvořáková, Zuzana; Lints, M.; Kůs, V.; Salupere, A.; Převorovský, Zdeněk

    2014-01-01

    Roč. 19, č. 12 (2014) ISSN 1435-4934. [European Conference on Non-Destructive Testing (ECNDT 2014) /11./. Praha, 06.10.2014-10.10.2014] Institutional support: RVO:61388998 Keywords : ultrasonic testing (UT) * signal processing * TR- NEWS * nonlinear time reversal * NDT * nonlinear acoustics Subject RIV: BI - Acoustics http://www.ndt.net/events/ECNDT2014/app/content/Slides/590_DosSantos_Rev1.pdf

  10. Prothrombin complex concentrate for reversal of vitamin K antagonist treatment in bleeding and non-bleeding patients

    DEFF Research Database (Denmark)

    Johansen, Mathias; Wikkelsø, Anne; Lunde, Jens

    2015-01-01

    BACKGROUND: Treatment with vitamin K antagonists is associated with increased morbidity and mortality. Reversal therapy with prothrombin complex concentrate (PCC) is used increasingly and is recommended in the treatment of patients with bleeding complications undertaking surgical interventions......, as well as patients at high risk of bleeding. Evidence is lacking regarding indication, dosing, efficacy and safety. OBJECTIVES: We assessed the benefits and harms of PCC compared with fresh frozen plasma in the acute medical and surgical setting involving vitamin K antagonist-treated bleeding and non...... finding a beneficial effect of PCC in reducing the volume of fresh frozen plasma (FFP) transfused to reverse the effect of vitamin K antagonist treatment. The number of new occurrences of transfusion of red blood cells (RBCs) did not seem to be associated with the use of PCC (RR 1.08, 95% CI 0.82 to 1...

  11. The use of microbial and chemical analyses to characterize the variations in fouling profile of seawater reverse osmosis (SWRO) membrane

    KAUST Repository

    Manes, Carmem Lara De O

    2013-01-01

    Biofouling of reverse osmosis (RO) membranes is one of the most common problems in desalinations plants reducing the efficiency of the water production process. The characterization of bacterial community composition from fouling layers as well as detailed analysis of surrounding chemical environment might reveal process specific bacterial groups/species that are involved in RO biofouling. In this study, advanced organics analytic methods (elemental analysis, FTIR, and ICP-OES) were combined with high-throughput 16S rRNA (pyro) sequencing to assess in parallel, the chemical properties and the active microbial community composition of SWRO membranes from a pilot desalination plant (MFT, Tarragona) in February 2011 and July 2011. Prefiltered ultrafiltration. waters fed SWRO membranes during third and fifth month of operation, respectively. SWRO samples were taken from three modules at different positions (first, fourth, and sixth) in order to investigate the spatial changes in fouling layers\\' chemical and microbiological composition. The overall assessment of chemical parameters revealed that fouling layers were mainly composed by bio and organic material (proteins and lipids). Ca and Fe were found to be the most abundant elements having an increasing concentration gradient according to the module position. Bacterial community composition of SWRO membranes is mostly represented by the Gammaproteobacteria class with interesting differences in genera/species spatial and temporal distribution. This preliminary result suggests that pretreatments and/or operational conditions might have selected different bacterial groups more adapted to colonize SWRO membranes. © 2013 Desalination Publications.

  12. On the Complexity of Reconstructing Chemical Reaction Networks

    DEFF Research Database (Denmark)

    Fagerberg, Rolf; Flamm, Christoph; Merkle, Daniel

    2013-01-01

    The analysis of the structure of chemical reaction networks is crucial for a better understanding of chemical processes. Such networks are well described as hypergraphs. However, due to the available methods, analyses regarding network properties are typically made on standard graphs derived from...... the full hypergraph description, e.g. on the so-called species and reaction graphs. However, a reconstruction of the underlying hypergraph from these graphs is not necessarily unique. In this paper, we address the problem of reconstructing a hypergraph from its species and reaction graph and show NP...

  13. Reverse engineering life: physical and chemical mimetics for controlled stem cell differentiation into cardiomyocytes.

    Science.gov (United States)

    Skuse, Gary R; Lamkin-Kennard, Kathleen A

    2013-01-01

    Our ability to manipulate stem cells in order to induce differentiation along a desired developmental pathway has improved immeasurably in recent years. That is in part because we have a better understanding of the intracellular and extracellular signals that regulate differentiation. However, there has also been a realization that stem cell differentiation is not regulated only by chemical signals but also by the physical milieu in which a particular stem cell exists. In this regard we are challenged to mimic both chemical and physical environments. Herein we describe a method to induce stem cell differentiation into cardiomyocytes using a combination of chemical and physical cues. This method can be applied to produce differentiated cells for research and potentially for cell-based therapy of cardiomyopathies.

  14. IgG Fab Fragments Forming Bivalent Complexes by a Conformational Mechanism That Is Reversible by Osmolytes*

    Science.gov (United States)

    Nelson, Alfreda D.; Hoffmann, Michele M.; Parks, Christopher A.; Dasari, Surendra; Schrum, Adam G.; Gil, Diana

    2012-01-01

    Generated by proteolytic cleavage of immunoglobulin, Fab fragments possess great promise as blocking reagents, able to bind receptors or other targets without inducing cross-linking. However, aggregation of Fab preparations is a common occurrence, which generates intrinsic stimulatory capacity and thwarts signal blockade strategies. Using a panel of biochemical approaches, including size exclusion chromatography, SDS-PAGE, mass spectrometry, and cell stimulation followed by flow cytometry, we have measured the oligomerization and acquisition of stimulatory capacity that occurs in four monoclonal IgG Fabs specific for TCR/CD3. Unexpectedly, we observed that all Fabs spontaneously formed complexes that were precisely bivalent, and these bivalent complexes possessed most of the stimulatory activity of each Fab preparation. Fabs composing bivalent complexes were more susceptible to proteolysis than monovalent Fabs, indicating a difference in conformation between the Fabs involved in these two different states of valency. Because osmolytes represent a class of compounds that stabilize protein folding and conformation, we sought to determine the extent to which the amino acid osmolyte l-proline might impact bivalent Fab complexation. We found that l-proline (i) inhibited the adoption of the conformation associated with bivalent complexation, (ii) preserved Fab monovalency, (iii) reversed the conformation of preformed bivalent Fabs to that of monovalent Fabs, and (iv) separated a significant percentage of preformed bivalent complexes into monovalent species. Thus, Fab fragments can adopt a conformation that is compatible with folding or packing of a bivalent complex in a process that can be inhibited by osmolytes. PMID:23109335

  15. Methylene Diphosphonate Chemical and Biological control of MDP complex

    International Nuclear Information System (INIS)

    Aungurarat, Angkanan; Ngamprayad, Tippanan

    2000-01-01

    Technetium-9 9m MDP easy prepared from MDP kits which different sources such as OAP (In house), SIGMA. The resulting Tc 9 9m -MDP preparations were controlled in chemical and biological tests to compare the different results in these cases: radiochemical purity, the quantity of starting material and biodistribution result

  16. Do High School Chemistry Examinations Inhibit Deeper Level Understanding of Dynamic Reversible Chemical Reactions?

    Science.gov (United States)

    Wheeldon, R.; Atkinson, R.; Dawes, A.; Levinson, R.

    2012-01-01

    Background and purpose: Chemistry examinations can favour the deployment of algorithmic procedures like Le Chatelier's Principle (LCP) rather than reasoning using chemical principles. This study investigated the explanatory resources which high school students use to answer equilibrium problems and whether the marks given for examination answers…

  17. The Impact of Complexity on the Expertise Reversal Effect: Experimental Evidence from Testing Accounting Students

    Science.gov (United States)

    Blayney, Paul; Kalyuga, Slava; Sweller, John

    2016-01-01

    Element interactivity is a central concept of cognitive load theory that defines the complexity of a learning task. The reduction of task complexity through a temporary segmentation or isolation of interacting elements was investigated with 104 students randomly assigned to an interacting elements group, where participants were required to deal…

  18. Application of a reversible chemical reaction system to solar thermal power plants

    Science.gov (United States)

    Hanseth, E. J.; Won, Y. S.; Seibowitz, L. P.

    1980-01-01

    Three distributed dish solar thermal power systems using various applications of SO2/SO3 chemical energy storage and transport technology were comparatively assessed. Each system features various roles for the chemical system: (1) energy storage only, (2) energy transport, or (3) energy transport and storage. These three systems were also compared with the dish-Stirling, using electrical transport and battery storage, and the central receiver Rankine system, with thermal storage, to determine the relative merit of plants employing a thermochemical system. As an assessment criterion, the busbar energy costs were compared. Separate but comparable solar energy cost computer codes were used for distributed receiver and central receiver systems. Calculations were performed for capacity factors ranging from 0.4 to 0.8. The results indicate that SO2/SO3 technology has the potential to be more cost effective in transporting the collected energy than in storing the energy for the storage capacity range studied (2-15 hours)

  19. {alpha},{beta}-Unsaturated Fischer carbene complexes as chemical multitalents

    Energy Technology Data Exchange (ETDEWEB)

    Meijere, A. de [Institut fuer Organische Chemie der George-August-Universitaet Goettingen (Germany)

    1995-12-31

    The well established reaction of {alpha},{beta}-unsaturated Fischer carbenechromium complexes 6(R{sup 1} = H) with alkynes normally proceeds with carbonyl insertion to yield 4-alkoxyphenols 9. Led by the incidental formation of a cyclopentadiene 3 from certain {beta}-aminosubstituted complexes 6(X = NR{sub 2}{sup 3}, R{sup 1} = cPr) the authors have studied the influences of the nature of substituents (R{sup 1}, X on 6; R{sub L}, R{sub S} in the alkyne; R{sup 3} in the amino group), solvents, and temperature on the outcome of the reaction. Imino substitution on complexes 6 leads to 2H-pyrroles 1, a free primary amino group (X = NH{sub 2}) to pyridines 5, and bulky substituents R{sup 1} to cyclopenta[b]pyrans 8 with double insertion of an alkyne. Eventually, appropriate conditions have been developed which permit to selectively prepare either 3-alkoxy-5-(dialkylamino)cyclopentadienes 3 (as synthetic equivalents of cyclopentenones 4), 5-(dialkylaminomethylene)cyclopent-2-enones 7, 3-alkoxy-2-(1{prime}-morpholino-1{prime}-alkenyl)cyclopent-2-enones 10, and 2-acyl-3-(dialkylamino)cyclopent-2-enones 11 from easily accessible carbene complexes 6 (X = NR{sub 2}{sup 3}) in high yields. Mechanistic aspects and implications of these novel transformations will be discussed.

  20. CALCULATION OF CHEMICAL ATMOSPHERE ESTIMATION GIVEN THE COMPLEX TERRAIN

    Directory of Open Access Journals (Sweden)

    M. M. Biliaiev

    2010-06-01

    Full Text Available The 3D numerical model was used to simulate the toxic gas dispersion over a complex terrain after an accident spillage. The model is based on the K-gradient transport model and the model of potential flow. The results of numerical experiment are presented.

  1. Identification of a methylated oligoribonucleotide as a potent inhibitor of HIV-1 reverse transcription complex.

    Science.gov (United States)

    Grigorov, Boyan; Bocquin, Anne; Gabus, Caroline; Avilov, Sergey; Mély, Yves; Agopian, Audrey; Divita, Gilles; Gottikh, Marina; Witvrouw, Myriam; Darlix, Jean-Luc

    2011-07-01

    Upon HIV-1 infection of a target cell, the viral reverse transcriptase (RT) copies the genomic RNA to synthesize the viral DNA. The genomic RNA is within the incoming HIV-1 core where it is coated by molecules of nucleocapsid (NC) protein that chaperones the reverse transcription process. Indeed, the RT chaperoning properties of NC extend from the initiation of cDNA synthesis to completion of the viral DNA. New and effective drugs against HIV-1 continue to be required, which prompted us to search for compounds aimed at inhibiting NC protein. Here, we report that the NC chaperoning activity is extensively inhibited in vitro by small methylated oligoribonucleotides (mODN). These mODNs were delivered intracellularly using a cell-penetrating-peptide and found to impede HIV-1 replication in primary human cells at nanomolar concentrations. Extensive analysis showed that viral cDNA synthesis was severely impaired by mODNs. Partially resistant viruses with mutations in NC and RT emerged after months of passaging in cell culture. A HIV-1 molecular clone (NL4.3) bearing these mutations was found to replicate at high concentrations of mODN, albeit with a reduced fitness. Small, methylated ODNs such as mODN-11 appear to be a new type of highly potent inhibitor of HIV-1.

  2. Towards a reverse Newman’s theorem in interactive information complexity

    Czech Academy of Sciences Publication Activity Database

    Brody, J.; Buhrman, H.; Koucký, Michal; Loff, B.; Speelman, F.; Vereshchagin, N.K.

    2016-01-01

    Roč. 76, č. 3 (2016), s. 749-781 ISSN 0178-4617 R&D Projects: GA AV ČR IAA100190902 Institutional support: RVO:67985840 Keywords : communication complexity * information complexity * information theory Subject RIV: BA - General Mathematics Impact factor: 0.735, year: 2016 http ://link.springer.com/article/10.1007%2Fs00453-015-0112-9

  3. Towards a reverse Newman’s theorem in interactive information complexity

    Czech Academy of Sciences Publication Activity Database

    Brody, J.; Buhrman, H.; Koucký, Michal; Loff, B.; Speelman, F.; Vereshchagin, N.K.

    2016-01-01

    Roč. 76, č. 3 (2016), s. 749-781 ISSN 0178-4617 R&D Projects: GA AV ČR IAA100190902 Institutional support: RVO:67985840 Keywords : communication complexity * information complexity * information theory Subject RIV: BA - General Mathematics Impact factor: 0.735, year: 2016 http://link.springer.com/article/10.1007%2Fs00453-015-0112-9

  4. From Molecules to Life: Quantifying the Complexity of Chemical and Biological Systems in the Universe.

    Science.gov (United States)

    Böttcher, Thomas

    2018-01-01

    Life is a complex phenomenon and much research has been devoted to both understanding its origins from prebiotic chemistry and discovering life beyond Earth. Yet, it has remained elusive how to quantify this complexity and how to compare chemical and biological units on one common scale. Here, a mathematical description of molecular complexity was applied allowing to quantitatively assess complexity of chemical structures. This in combination with the orthogonal measure of information complexity resulted in a two-dimensional complexity space ranging over the entire spectrum from molecules to organisms. Entities with a certain level of information complexity directly require a functionally complex mechanism for their production or replication and are hence indicative for life-like systems. In order to describe entities combining molecular and information complexity, the term biogenic unit was introduced. Exemplified biogenic unit complexities were calculated for ribozymes, protein enzymes, multimeric protein complexes, and even an entire virus particle. Complexities of prokaryotic and eukaryotic cells, as well as multicellular organisms, were estimated. Thereby distinct evolutionary stages in complexity space were identified. The here developed approach to compare the complexity of biogenic units allows for the first time to address the gradual characteristics of prebiotic and life-like systems without the need for a definition of life. This operational concept may guide our search for life in the Universe, and it may direct the investigations of prebiotic trajectories that lead towards the evolution of complexity at the origins of life.

  5. Silver Nanowire Embedded Colorless Polyimide Heater for Wearable Chemical Sensors: Improved Reversible Reaction Kinetics of Optically Reduced Graphene Oxide.

    Science.gov (United States)

    Choi, Seon-Jin; Kim, Sang-Joon; Jang, Ji-Soo; Lee, Ji-Hyun; Kim, Il-Doo

    2016-09-14

    Optically reduced graphene oxide (ORGO) sheets are successfully integrated on silver nanowire (Ag NW)-embedded transparent and flexible substrate. As a heating element, Ag NWs are embedded in a colorless polyimide (CPI) film by covering Ag NW networks using polyamic acid and subsequent imidization. Graphene oxide dispersed aqueous solution is drop-coated on the Ag NW-embedded CPI (Ag NW-CPI) film and directly irradiated by intense pulsed light to obtain ORGO sheets. The heat generation property of Ag NW-CPI film is investigated by applying DC voltage, which demonstrates unprecedentedly reliable and stable characteristics even in dynamic bending condition. To demonstrate the potential application in wearable chemical sensors, NO 2 sensing characteristic of ORGO is investigated with respect to the different heating temperature (22.7-71.7 °C) of Ag NW-CPI film. The result reveals that the ORGO sheets exhibit high sensitivity of 2.69% with reversible response/recovery sensing properties and minimal deviation of baseline resistance of around 1% toward NO 2 molecules when the temperature of Ag NW-CPI film is 71.7 °C. This work first demonstrates the improved reversible NO 2 sensing properties of ORGO sheets on flexible and transparent Ag NW-CPI film assisted by Ag NW heating networks. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Surface modification of reverse osmosis desalination membranes by thin-film coatings deposited by initiated chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ozaydin-Ince, Gozde, E-mail: gozdeince@sabanciuniv.edu [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Matin, Asif, E-mail: amatin@mit.edu [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Khan, Zafarullah, E-mail: zukhan@mit.edu [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Zaidi, S.M. Javaid, E-mail: zaidismj@kfupm.edu.sa [Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Gleason, Karen K., E-mail: kkgleasn@mit.edu [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2013-07-31

    Thin-film polymeric reverse osmosis membranes, due to their high permeation rates and good salt rejection capabilities, are widely used for seawater desalination. However, these membranes are prone to biofouling, which affects their performance and efficiency. In this work, we report a method to modify the membrane surface without damaging the active layer or significantly affecting the performance of the membrane. Amphiphilic copolymer films of hydrophilic hydroxyethylmethacrylate and hydrophobic perfluorodecylacrylate (PFA) were synthesized and deposited on commercial RO membranes using an initiated chemical vapor deposition technique which is a polymer deposition technique that involves free-radical polymerization initiated by gas-phase radicals. Relevant surface characteristics such as hydrophilicity and roughness could be systematically controlled by varying the polymer chemistry. Increasing the hydrophobic PFA content in the films leads to an increase in the surface roughness and hydrophobicity. Furthermore, the surface morphology studies performed using the atomic force microscopy show that as the thickness of the coating increases average surface roughness increases. Using this knowledge, the coating thickness and chemistry were optimized to achieve high permeate flux and to reduce cell attachment. Results of the static bacterial adhesion tests show that the attachment of bacterial cells is significantly reduced on the coated membranes. - Highlights: • Thin films are deposited on reverse osmosis membranes. • Amphiphilic thin films are resistant to protein attachment. • The permeation performance of the membranes is not affected by the coating. • The thin film coatings delayed the biofouling.

  7. Reversible DNA condensation induced by a tetranuclear nickel(II) complex.

    Science.gov (United States)

    Dong, Xindian; Wang, Xiaoyong; He, Yafeng; Yu, Zhen; Lin, Miaoxin; Zhang, Changli; Wang, Jing; Song, Yajie; Zhang, Yangmiao; Liu, Zhipeng; Li, Yizhi; Guo, Zijian

    2010-12-17

    DNA condensing agents play a critical role in gene therapy. A tetranuclear nickel(II) complex, [Ni(II)(4)(L-2H)(H(2)O)(6)(CH(3)CH(2)OH)(2)]·6NO(3) (L=3,3',5,5'-tetrakis{[(2-hydroxyethyl)(pyridin-2-ylmethyl)amino]methyl}biphenyl-4,4'-diol), has been synthesized as a nonviral vector to induce DNA condensation. X-ray crystallographic data indicate that the complex crystallizes in the monoclinic system with space group P2(1)/n, a=10.291(9), b=24.15(2), c=13.896(11) Å, and β=98.175(13)°. The DNA condensation induced by the complex has been investigated by means of UV/Vis spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy, dynamic light scattering, atomic force microscopy, gel electrophoresis assay, and zeta potential analysis. The complex interacts strongly with DNA through electrostatic attraction and induces its condensation into globular nanoparticles at low concentration. The release of DNA from its compact state has been achieved using the chelator ethylenediaminetetraacetic acid (EDTA) for the first time. Other essential properties, such as DNA cleavage inactivity and biocompatibility, have also been examined in vitro. In general, the complex satisfies the requirements of a gene vector in all of these respects.

  8. Click and chemically triggered declick reactions through reversible amine and thiol coupling via a conjugate acceptor

    Science.gov (United States)

    Diehl, Katharine L.; Kolesnichenko, Igor V.; Robotham, Scott A.; Bachman, J. Logan; Zhong, Ye; Brodbelt, Jennifer S.; Anslyn, Eric V.

    2016-10-01

    The coupling and decoupling of molecular units is a fundamental undertaking of organic chemistry. Herein we report the use of a very simple conjugate acceptor, derived from Meldrum's acid, for the sequential ‘clicking’ together of an amine and a thiol in aqueous conditions at neutral pH. Subsequently, this linkage can be ‘declicked’ by a chemical trigger to release the original amine and thiol undisturbed. The reactivity differs from that of other crosslinking agents because the selectivity for sequential functionalization derives from an altering of the electrophilicity of the conjugate acceptor on the addition of the amine. We describe the use of the procedure to modify proteins, create multicomponent libraries and synthesize oligomers, all of which can be declicked to their starting components in a controlled fashion when desired. Owing to the mild reaction conditions and ease of use in a variety of applications, the method is predicted to have wide utility.

  9. Computational Analyses of Complex Flows with Chemical Reactions

    Science.gov (United States)

    Bae, Kang-Sik

    The heat and mass transfer phenomena in micro-scale for the mass transfer phenomena on drug in cylindrical matrix system, the simulation of oxygen/drug diffusion in a three dimensional capillary network, and a reduced chemical kinetic modeling of gas turbine combustion for Jet propellant-10 have been studied numerically. For the numerical analysis of the mass transfer phenomena on drug in cylindrical matrix system, the governing equations are derived from the cylindrical matrix systems, Krogh cylinder model, which modeling system is comprised of a capillary to a surrounding cylinder tissue along with the arterial distance to veins. ADI (Alternative Direction Implicit) scheme and Thomas algorithm are applied to solve the nonlinear partial differential equations (PDEs). This study shows that the important factors which have an effect on the drug penetration depth to the tissue are the mass diffusivity and the consumption of relevant species during the time allowed for diffusion to the brain tissue. Also, a computational fluid dynamics (CFD) model has been developed to simulate the blood flow and oxygen/drug diffusion in a three dimensional capillary network, which are satisfied in the physiological range of a typical capillary. A three dimensional geometry has been constructed to replicate the one studied by Secomb et al. (2000), and the computational framework features a non-Newtonian viscosity model for blood, the oxygen transport model including in oxygen-hemoglobin dissociation and wall flux due to tissue absorption, as well as an ability to study the diffusion of drugs and other materials in the capillary streams. Finally, a chemical kinetic mechanism of JP-10 has been compiled and validated for a wide range of combustion regimes, covering pressures of 1atm to 40atm with temperature ranges of 1,200 K--1,700 K, which is being studied as a possible Jet propellant for the Pulse Detonation Engine (PDE) and other high-speed flight applications such as hypersonic

  10. Building Structural Complexity in Semiconductor Nanocrystals through Chemical Transformations

    Energy Technology Data Exchange (ETDEWEB)

    Sadtler, Bryce F [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2009-05-01

    Methods are presented for synthesizing nanocrystal heterostructures comprised of two semiconductor materials epitaxially attached within individual nanostructures. The chemical transformation of cation exchange, where the cations within the lattice of an ionic nanocrystal are replaced with a different metal ion species, is used to alter the chemical composition at specific regions ofa nanocrystal. Partial cation exchange was performed in cadmium sulfide (CdS) nanorods of well-defined size and shape to examine the spatial organization of materials within the resulting nanocrystal heterostructures. The selectivity for cation exchange to take place at different facets of the nanocrystal plays an important role in determining the resulting morphology of the binary heterostructure. The exchange of copper (I) (Cu+) cations in CdS nanorods occurs preferentially at the ends of the nanorods. Theoretical modeling of epitaxial attachments between different facets of CdS and Cu2S indicate that the selectivity for cation exchange at the ends of the nanorods is a result of the low formation energy of the interfaces produced. During silver (I) (Ag+) cation exchange in CdS nanorods, non-selective nucleation of silver sulfide (Ag2S), followed by partial phase segregation leads to significant changes in the spatial arrangement of CdS and Ag2S regions at the exchange reaction proceeds through the nanocrystal. A well-ordered striped pattern of alternating CdS and Ag2S segments is found at intermediate fractions of exchange. The forces mediating this spontaneous process are a combination of Ostwald ripening to reduce the interfacial area along with a strain-induced repulsive interaction between Ag2S segments. To elucidate why Cu+ and Ag+ cation exchange with CdS nanorods produce different morphologies, models for epitaxial attachments between various facets of CdS with Cu2S or

  11. Identifying Slow Molecular Motions in Complex Chemical Reactions.

    Science.gov (United States)

    Piccini, GiovanniMaria; Polino, Daniela; Parrinello, Michele

    2017-09-07

    We have studied the cyclization reaction of deprotonated 4-chloro-1-butanethiol to tetrahydrothiophene by means of well-tempered metadynamics. To properly select the collective variables, we used the recently proposed variational approach to conformational dynamics within the framework of metadyanmics. This allowed us to select the appropriate linear combinations from a set of collective variables representing the slow degrees of freedom that best describe the slow modes of the reaction. We performed our calculations at three different temperatures, namely, 300, 350, and 400 K. We show that the choice of such collective variables allows one to easily interpret the complex free-energy surface of such a reaction by univocal identification of the conformers belonging to reactants and product states playing a fundamental role in the reaction mechanism.

  12. [Physico-chemical features of dinitrosyl iron complexes with natural thiol-containing ligands underlying biological activities of these complexes].

    Science.gov (United States)

    Vanin, A F; Borodulin, R R; Kubrina, L N; Mikoian, V D; Burbaev, D Sh

    2013-01-01

    Current notions and new experimental data of the authors on physico-chemical features of dinitrosyl iron complexes with natural thiol-containing ligands (glutathione or cysteine), underlying the ability of the complexes to act as NO molecule and nitrosonium ion donors, are considered. This ability determines various biological activities of dinitrosyl iron complexes--inducing long-lasting vasodilation and thereby long-lasting hypotension in human and animals, inhibiting pellet aggregation, increasing red blood cell elasticity, thereby stimulating microcirculation, and reducing necrotic zone in animals with myocardial infarction. Moreover, dinitrosyl iron complexes are capable of accelerating skin wound healing, improving the function of penile cavernous tissue, blocking apoptosis development in cell cultures. When decomposed dinitrosyl iron complexes can exert cytotoxic effect that can be used for curing infectious and carcinogenic pathologies.

  13. Thermally induced delay and reversal of liquid film dewetting on chemically patterned surfaces.

    Science.gov (United States)

    Kalpathy, Sreeram K; Francis, Lorraine F; Kumar, Satish

    2013-10-15

    A thin liquid film resting on a solid substrate that is heated or cooled from below experiences surface tension gradients, which lead to Marangoni flows. We explore the behavior of such a film on a chemically patterned substrate which drives film dewetting in order to determine how surface patterning and applied temperature gradients can be designed to influence the behavior of thin-film coatings. A nonlinear partial differential equation for the film height based on lubrication theory is solved numerically for a broad range of problem parameters. Uniform cooling of the substrate is found to significantly delay dewetting that is driven by wettability gradients. Uniform heating speeds up dewetting but can destroy the near-perfect templating imposed by the surface patterning. However, localized heating and cooling together can accelerate dewetting while maintaining templating quality. Localized heating and cooling can also be used to drive liquid onto areas that it would dewet from in the absence of heating. Overall, these results indicate that applied temperature gradients can significantly influence dewetting driven by surface patterning, and suggest strategies for the creation of spatially patterned thin-film coatings and flow control in microfluidic devices. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Switchable photovoltaic windows enabled by reversible photothermal complex dissociation from methylammonium lead iodide.

    Science.gov (United States)

    Wheeler, Lance M; Moore, David T; Ihly, Rachelle; Stanton, Noah J; Miller, Elisa M; Tenent, Robert C; Blackburn, Jeffrey L; Neale, Nathan R

    2017-11-23

    Materials with switchable absorption properties have been widely used for smart window applications to reduce energy consumption and enhance occupant comfort in buildings. In this work, we combine the benefits of smart windows with energy conversion by producing a photovoltaic device with a switchable absorber layer that dynamically responds to sunlight. Upon illumination, photothermal heating switches the absorber layer-composed of a metal halide perovskite-methylamine complex-from a transparent state (68% visible transmittance) to an absorbing, photovoltaic colored state (less than 3% visible transmittance) due to dissociation of methylamine. After cooling, the methylamine complex is re-formed, returning the absorber layer to the transparent state in which the device acts as a window to visible light. The thermodynamics of switching and performance of the device are described. This work validates a photovoltaic window technology that circumvents the fundamental tradeoff between efficient solar conversion and high visible light transmittance that limits conventional semitransparent PV window designs.

  15. Leaching behavior and chemical stability of copper butyl xanthate complex under acidic conditions.

    Science.gov (United States)

    Chang, Yi Kuo; Chang, Juu En; Chiang, Li Choung

    2003-08-01

    Although xanthate addition can be used for treating copper-containing wastewater, a better understanding of the leaching toxicity and the stability characteristics of the copper xanthate complexes formed is essential. This work was undertaken to evaluate the leaching behavior of copper xanthate complex precipitates by means of toxicity characteristics leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) using 1 N acetic acid solution as the leachant. Also, the chemical stability of the copper xanthate complex during extraction has been examined with the studying of variation of chemical structure using UV-vis, Fourier transform infrared and X-ray photoelectron spectroscopies (XPS). Both TCLP and SDLT results showed that a negligible amount of copper ion was leached out from the copper xanthate complex precipitate, indicating that the complex exhibited a high degree of copper leaching stability under acidic conditions. Nevertheless, chemical structure of the copper xanthate complex precipitate varied during the leaching tests. XPS data suggested that the copper xanthate complex initially contained both cupric and cuprous xanthate, but the unstable cupric xanthate change to the cuprous form after acid extraction, indicating the cuprous xanthate to be the final stabilizing structure. Despite that, the changes of chemical structure did not induce the rapid leaching of copper from the copper xanthate complex.

  16. Thrombotic safety of prothrombin complex concentrate (Beriplex P/N) for dabigatran reversal in a rabbit model.

    Science.gov (United States)

    Herzog, Eva; Kaspereit, Franz J; Krege, Wilfried; Doerr, Baerbel; van Ryn, Joanne; Dickneite, Gerhard; Pragst, Ingo

    2014-09-01

    In vivo animal data have shown prothrombin complex concentrate (PCC) to be effective in preventing bleeding induced by excessive plasma levels of the direct thrombin inhibitor dabigatran. This animal model study was designed to determine the risk of thrombosis associated with administration of a PCC (Beriplex P/N) to reverse dabigatran-induced bleeding. Anesthetized rabbits were treated with initial 0, 75, 200 or 450 μg kg(-1) dabigatran boluses followed by continuous infusions to maintain elevated plasma dabigatran levels. At 15 min after the start of dabigatran administration, PCC doses of 0, 50 or 300 IU kg(-1) were administered. Thereafter, coagulation in an arteriovenous (AV) shunt was evaluated and histopathologic examination for thrombotic changes performed. Venous thrombosis was also assessed in a modified Wessler model. At the suprapharmacologic dose of 300 IU kg(-1), PCC increased thrombus weight during AV shunting, but this effect could be prevented by dabigatran at all tested doses. AV shunt occlusion after PCC administration was delayed by 75 μg kg(-1) dabigatran and abolished by progressively higher dabigatran doses. High-dose treatment with 300 IU kg(-1) PCC resulted in histologically evident low-grade pulmonary thrombi; however, that effect could be blocked by dabigatran in a dose-dependent manner (p=0.034). In rabbits treated with high-dose PCC, dabigatran inhibited thrombus formation during venous stasis. PCC effectively reversed dabigatran-induced bleeding. In this animal study, thrombosis after PCC administration could be prevented in the presence of dabigatran. PCC reversed dabigatran-induced excessive bleeding while retaining protective anticoagulatory activity of dabigatran. Copyright © 2014. Published by Elsevier Ltd.

  17. More efficient reversal of dabigatran inhibition of coagulation by activated prothrombin complex concentrate or recombinant factor VIIa than by four-factor prothrombin complex concentrate.

    Science.gov (United States)

    Lindahl, Tomas L; Wallstedt, Maria; Gustafsson, Kerstin M; Persson, Egon; Hillarp, Andreas

    2015-03-01

    The number of patients on antithrombotic treatment due to atrial fibrillation and venous thromboembolism is increasing fast due to an aging population. A growing proportion will be treated with novel oral anticoagulants, the first in clinical use was the direct oral thrombin inhibitor dabigatran (Pradaxa®). A small percentage of the patients on dabigatran will experience serious bleeding or be in need of urgent surgery. The aim of this study was to test the effects of different hemostatic agents in potentially reversing the anticoagulant effects in vitro in blood or platelet-rich plasma (PRP) spiked with dabigatran. Whole blood or PRP was spiked with the active substance dabigatran, 200 μg/L. We measured clotting time being induced by 1.4 pmol/L tissue factor using the instrument ReoRox2™ and initial clot growth velocity from a tissue factor covered surface using the instrument Thrombodynamics Analyzer T-2™. Dabigatran prolonged clotting time 5-fold but reduced clot growth velocity only slightly. The reversing effects of prothrombin complex concentrates (PCC), activated PCC (APCC) and recombinant activated factor VII (rFVIIa) were then tested. APCC (1.8 U/mL) reduced the prolonged clotting time by 1/3, rFVIIa (2 μg/L) only slightly (n = 10-20). The reduction was not significant using Mann-Whitney test but significant using t-test with Bonferronis' correction for multiple comparisons, whereas PCC (0.56 U/mL) had no effect on clotting time. APCC doubled initial clot growth velocity, although even more in the absence of dabigatran. In conclusion, APCC and rFVIIa, but not PCC, seem to reverse, at least partially, some effects of dabigatran on coagulation parameters. Systematic evaluation of case reports, registries and, ultimately, randomized clinical trials are needed to elucidate potential benefit for patients. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Two Iron Complexes as Homogeneous and Heterogeneous Catalysts for the Chemical Fixation of Carbon Dioxide.

    Science.gov (United States)

    Karan, Chandan Kumar; Bhattacharjee, Manish

    2018-04-16

    Two new bimetallic iron-alkali metal complexes of amino acid (serine)-based reduced Schiff base ligand were synthesized and structurally characterized. Their efficacy as catalysts for the chemical fixation of carbon dioxide was explored. The heterogeneous version of the catalytic reaction was developed by the immobilization of these homogeneous bimetallic iron-alkali metal complexes in an anion-exchange resin. The resin-bound complexes can be used as recyclable catalysts up to six cycles.

  19. Chemical Hydrogen Storage Using Polyhedral Borane Anions and Aluminum-Ammonia-Borane Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, M. Frederick; Jalisatgi, Satish S.; Safronov, Alexander V.; Lee, Han Beak; Wu, Jianguo

    2010-10-01

    mediated hydrogenation process leading to reversibility. The Al-AB complexes have comparable hydrogen capacity with other M-AB and have potential to meet DOE’s 2010 and 2015 targets for system wt%.

  20. Elution behavior of N-heterocyclic derivatives of mixed ruthenium(II)-sulfoxide complexes in reversed-phase high-performance liquid chromatography

    International Nuclear Information System (INIS)

    Toma, H.E.; Silva, D.O.

    1991-01-01

    The elution behaviour of a series of dichlorobis-(dimethylsulfoxide)bis(N-heterocyclic) ruthenium(II) complexes has been investigated using reversed-phase HPLC. Similar trends as those displayed by the free N-heterocyclic bases have been observed for the complexes, essentially reflecting the hydrophobic properties of the aromatic ligands. (orig.)

  1. Systematic reduction of complex tropospheric chemical mechanisms, Part II: Lumping using a time-scale based approach

    Directory of Open Access Journals (Sweden)

    L. E. Whitehouse

    2004-01-01

    Full Text Available This paper presents a formal method of species lumping that can be applied automatically to intermediate compounds within detailed and complex tropospheric chemical reaction schemes. The method is based on grouping species with reference to their chemical lifetimes and reactivity structures. A method for determining the forward and reverse transformations between individual and lumped compounds is developed. Preliminary application to the Leeds Master Chemical Mechanism (MCMv2.0 has led to the removal of 734 species and 1777 reactions from the scheme, with minimal degradation of accuracy across a wide range of test trajectories relevant to polluted tropospheric conditions. The lumped groups are seen to relate to groups of peroxy acyl nitrates, nitrates, carbonates, oxepins, substituted phenols, oxeacids and peracids with similar lifetimes and reaction rates with OH. In combination with other reduction techniques, such as sensitivity analysis and the application of the quasi-steady state approximation (QSSA, a reduced mechanism has been developed that contains 35% of the number of species and 40% of the number of reactions compared to the full mechanism. This has led to a speed up of a factor of 8 in terms of computer calculation time within box model simulations.

  2. Low energy costs of F1Fo ATP synthase reversal in colon carcinoma cells deficient in mitochondrial complex IV.

    Science.gov (United States)

    Zhdanov, Alexander V; Andreev, Dmitry E; Baranov, Pavel V; Papkovsky, Dmitri B

    2017-05-01

    Mitochondrial polarisation is paramount for a variety of cellular functions. Under ischemia, mitochondrial membrane potential (ΔΨm) and proton gradient (ΔpH) are maintained via a reversal of mitochondrial F1Fo ATP synthase (mATPase), which can rapidly deplete ATP and drive cells into energy crisis. We found that under normal conditions in cells with disassembled cytochrome c oxidase complex (COX-deficient HCT116), mATPase maintains ΔΨm at levels only 15-20% lower than in WT cells, and for this utilises relatively little ATP. For a small energy expenditure, mATPase enables mitochondrial ΔpH, protein import, Ca 2+ turnover, and supports free radical detoxication machinery enlarged to protect the cells from oxidative damage. Whereas in COX-deficient cells the main source of ATP is glycolysis, the ΔΨm is still maintained upon inhibition of the adenine nucleotide translocators with bongkrekic acid and carboxyatractyloside, indicating that the role of ANTs is redundant, and matrix substrate level phosphorylation alone or in cooperation with ATP-Mg/P i carriers can continuously support the mATPase activity. Intriguingly, we found that mitochondrial complex III is active, and it contributes not only to free radical production, but also to ΔΨm maintenance and energy budget of COX-deficient cells. Overall, this study demonstrates that F1Fo ATP synthase can support general mitochondrial and cellular functions, working in extremely efficient 'energy saving' reverse mode and flexibly recruiting free radical detoxication and ATP producing / transporting pathways. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Genetic and chemical diversity of high mucilaginous plants of Sida complex by ISSR markers and chemical fingerprinting.

    Science.gov (United States)

    Thul, Sanjog T; Srivastava, Ankit K; Singh, Subhash C; Shanker, Karuna

    2011-09-01

    A method was developed based on multiple approaches wherein DNA and chemical analysis was carried out toward differentiation of important species of Sida complex that is being used for commercial preparation. Isolated DNA samples were successfully performed through PCR amplification using ISSR markers and degree of genetic diversity among the different species of Sida is compared with that of chemical diversity. For genetic fingerprint investigation, selected 10 ISSR primers generating reproducible banding patterns were used. Among the total of 63 amplicons, 62 were recorded as polymorphic, genetic similarity index deduced from ISSR profiles ranged from 12 to 51%. Based on similarity index, S. acuta and S. rhombifolia found to be most similar (51%). High number of species-specific bands played pivotal role to delineate species at genetic level. Investigation based on HPTLC fingerprints analysis revealed 23 bands representing to characteristic chemicals and similarity index ranged from 73 to 91%. Prominent distinguishable bands were observed only in S. acuta, while S. cordifolia and S. rhombifolia shared most bands making them difficult to identify on chemical fingerprint basis. This report summarizes the genotypic and chemotypic diversity and the use of profiles for authentication of species of Sida complex.

  4. Influence of electronic and steric effects on stability constants and electrochemical reversibility of divalent ion complexes with glycine and sarcosine

    International Nuclear Information System (INIS)

    Cukrowski, Ignacy; Marques, Helder M.; Mkwizu, Tumaini S.; Magampa, Philemon P.; Serge, Claudette

    2007-01-01

    Cd II complexes with glycine (gly) and sarcosine (sar) were studied by glass electrode potentiometry, direct current polarography, virtual potentiometry, and molecular modelling. The electrochemically reversible Cd II -glycine-OH labile system was best described by a model consisting of M(HL), ML, ML 2 , ML 3 , ML(OH) and ML 2 (OH) (M = Cd II , L = gly) with the overall stability constants, as log β, determined to be 10.30 ± 0.05, 4.21 ± 0.03, 7.30 ± 0.05, 9.84 ± 0.04, 8.9 ± 0.1, and 10.75 ± 0.10, respectively. In case of the electrochemically quasi-reversible Cd II -sarcosine-OH labile system, only ML, ML 2 and ML 3 (M = Cd II , L = sar) were found and their stability constants, as log β, were determined to be 3.80 ± 0.03, 6.91 ± 0.07, and 8.9 ± 0.4, respectively. Stability constants for the ML complexes, the prime focus of this work, were thus established with an uncertainty smaller than 0.05 log units. The observed departure from electrochemical reversibility for the Cd-sarcosine-OH system was attributed mainly to the decrease in the transfer coefficient α. The MM2 force field, supplemented by additional parameters, reproduced the reported crystal structures of diaqua-bis(glycinato-O,N)nickel(II) and fac-tri(glycinato)-nickelate(II) very well. These parameters were used to predict structures of all possible isomers of (i) [Ni(H 2 O) 4 (gly)] + and [Ni(H 2 O) 4 (sar)] + ; and (ii) [Ni(H 2 O) 3 (IDA)] and [Ni(H 2 O) 3 (MIDA)] (IDA = iminodiacetic acid, MIDA = N-methyl iminodiacetic acid) by molecular mechanics/simulated annealing methods. The change in strain energy, ΔU str , that accompanies the substitution of one ligand by another (ML + L' → ML' + L), was computed and a strain energy ΔU str = +0.28 kcal mol -1 for the reaction [Ni(H 2 O) 4 (gly)] + + sar → [Ni(H 2 O) 4 (sar)] + + gly was found. This predicts the monoglycine complex to be marginally more stable. By contrast, for the reaction [Ni(H 2 O) 3 IDA] + MIDA → [Ni(H 2 O) 3 MIDA] + IDA

  5. Structural Insights into HIV Reverse Transcriptase Mutations Q151M and Q151M Complex That Confer Multinucleoside Drug Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Das, Kalyan; Martinez, Sergio E.; Arnold, Eddy

    2017-04-10

    HIV-1 reverse transcriptase (RT) is targeted by multiple drugs. RT mutations that confer resistance to nucleoside RT inhibitors (NRTIs) emerge during clinical use. Q151M and four associated mutations, A62V, V75I, F77L, and F116Y, were detected in patients failing therapies with dideoxynucleosides (didanosine [ddI], zalcitabine [ddC]) and/or zidovudine (AZT). The cluster of the five mutations is referred to as the Q151M complex (Q151Mc), and an RT or virus containing Q151Mc exhibits resistance to multiple NRTIs. To understand the structural basis for Q151M and Q151Mc resistance, we systematically determined the crystal structures of the wild-type RT/double-stranded DNA (dsDNA)/dATP (complex I), wild-type RT/dsDNA/ddATP (complex II), Q151M RT/dsDNA/dATP (complex III), Q151Mc RT/dsDNA/dATP (complex IV), and Q151Mc RT/dsDNA/ddATP (complex V) ternary complexes. The structures revealed that the deoxyribose rings of dATP and ddATP have 3'-endo and 3'-exo conformations, respectively. The single mutation Q151M introduces conformational perturbation at the deoxynucleoside triphosphate (dNTP)-binding pocket, and the mutated pocket may exist in multiple conformations. The compensatory set of mutations in Q151Mc, particularly F116Y, restricts the side chain flexibility of M151 and helps restore the DNA polymerization efficiency of the enzyme. The altered dNTP-binding pocket in Q151Mc RT has the Q151-R72 hydrogen bond removed and has a switched conformation for the key conserved residue R72 compared to that in wild-type RT. On the basis of a modeled structure of hepatitis B virus (HBV) polymerase, the residues R72, Y116, M151, and M184 in Q151Mc HIV-1 RT are conserved in wild-type HBV polymerase as residues R41, Y89, M171, and M204, respectively; functionally, both Q151Mc HIV-1 and wild-type HBV are resistant to dideoxynucleoside analogs.

  6. Chemical Equilibrium Models for the S3 State of the Oxygen-Evolving Complex of Photosystem II.

    Science.gov (United States)

    Isobe, Hiroshi; Shoji, Mitsuo; Shen, Jian-Ren; Yamaguchi, Kizashi

    2016-01-19

    We have performed hybrid density functional theory (DFT) calculations to investigate how chemical equilibria can be described in the S3 state of the oxygen-evolving complex in photosystem II. For a chosen 340-atom model, 1 stable and 11 metastable intermediates have been identified within the range of 13 kcal mol(-1) that differ in protonation, charge, spin, and conformational states. The results imply that reversible interconversion of these intermediates gives rise to dynamic equilibria that involve processes with relocations of protons and electrons residing in the Mn4CaO5 cluster, as well as bound water ligands, with concomitant large changes in the cluster geometry. Such proton tautomerism and redox isomerism are responsible for reversible activation/deactivation processes of substrate oxygen species, through which Mn-O and O-O bonds are transiently ruptured and formed. These results may allow for a tentative interpretation of kinetic data on substrate water exchange on the order of seconds at room temperature, as measured by time-resolved mass spectrometry. The reliability of the hybrid DFT method for the multielectron redox reaction in such an intricate system is also addressed.

  7. The influence of the “cage effect” on the mechanism of reversible bimolecular multistage chemical reactions in solutions

    International Nuclear Information System (INIS)

    Doktorov, Alexander B.

    2015-01-01

    Manifestations of the “cage effect” at the encounters of reactants are theoretically treated by the example of multistage reactions in liquid solutions including bimolecular exchange reactions as elementary stages. It is shown that consistent consideration of quasi-stationary kinetics of multistage reactions (possible only in the framework of the encounter theory) for reactions proceeding near reactants contact can be made on the basis of the concepts of a “cage complex.” Though mathematically such a consideration is more complicated, it is more clear from the standpoint of chemical notions. It is established that the presence of the “cage effect” leads to some important effects not inherent in reactions in gases or those in solutions proceeding in the kinetic regime, such as the appearance of new transition channels of reactant transformation that cannot be caused by elementary event of chemical conversion for the given mechanism of reaction. This results in that, for example, rate constant values of multistage reaction defined by standard kinetic equations of formal chemical kinetics from experimentally measured kinetics can differ essentially from real values of these constants

  8. The influence of the "cage effect" on the mechanism of reversible bimolecular multistage chemical reactions in solutions.

    Science.gov (United States)

    Doktorov, Alexander B

    2015-08-21

    Manifestations of the "cage effect" at the encounters of reactants are theoretically treated by the example of multistage reactions in liquid solutions including bimolecular exchange reactions as elementary stages. It is shown that consistent consideration of quasi-stationary kinetics of multistage reactions (possible only in the framework of the encounter theory) for reactions proceeding near reactants contact can be made on the basis of the concepts of a "cage complex." Though mathematically such a consideration is more complicated, it is more clear from the standpoint of chemical notions. It is established that the presence of the "cage effect" leads to some important effects not inherent in reactions in gases or those in solutions proceeding in the kinetic regime, such as the appearance of new transition channels of reactant transformation that cannot be caused by elementary event of chemical conversion for the given mechanism of reaction. This results in that, for example, rate constant values of multistage reaction defined by standard kinetic equations of formal chemical kinetics from experimentally measured kinetics can differ essentially from real values of these constants.

  9. The influence of the “cage effect” on the mechanism of reversible bimolecular multistage chemical reactions in solutions

    Energy Technology Data Exchange (ETDEWEB)

    Doktorov, Alexander B., E-mail: doktorov@kinetics.nsc.ru [Voevodsky Institute of Chemical Kinetics & Combustion, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia and Novosibirsk State University, Novosibirsk 630090 (Russian Federation)

    2015-08-21

    Manifestations of the “cage effect” at the encounters of reactants are theoretically treated by the example of multistage reactions in liquid solutions including bimolecular exchange reactions as elementary stages. It is shown that consistent consideration of quasi-stationary kinetics of multistage reactions (possible only in the framework of the encounter theory) for reactions proceeding near reactants contact can be made on the basis of the concepts of a “cage complex.” Though mathematically such a consideration is more complicated, it is more clear from the standpoint of chemical notions. It is established that the presence of the “cage effect” leads to some important effects not inherent in reactions in gases or those in solutions proceeding in the kinetic regime, such as the appearance of new transition channels of reactant transformation that cannot be caused by elementary event of chemical conversion for the given mechanism of reaction. This results in that, for example, rate constant values of multistage reaction defined by standard kinetic equations of formal chemical kinetics from experimentally measured kinetics can differ essentially from real values of these constants.

  10. An analytical platform for mass spectrometry-based identification and chemical analysis of RNA in ribonucleoprotein complexes.

    Science.gov (United States)

    Taoka, Masato; Yamauchi, Yoshio; Nobe, Yuko; Masaki, Shunpei; Nakayama, Hiroshi; Ishikawa, Hideaki; Takahashi, Nobuhiro; Isobe, Toshiaki

    2009-11-01

    We describe here a mass spectrometry (MS)-based analytical platform of RNA, which combines direct nano-flow reversed-phase liquid chromatography (RPLC) on a spray tip column and a high-resolution LTQ-Orbitrap mass spectrometer. Operating RPLC under a very low flow rate with volatile solvents and MS in the negative mode, we could estimate highly accurate mass values sufficient to predict the nucleotide composition of a approximately 21-nucleotide small interfering RNA, detect post-transcriptional modifications in yeast tRNA, and perform collision-induced dissociation/tandem MS-based structural analysis of nucleolytic fragments of RNA at a sub-femtomole level. Importantly, the method allowed the identification and chemical analysis of small RNAs in ribonucleoprotein (RNP) complex, such as the pre-spliceosomal RNP complex, which was pulled down from cultured cells with a tagged protein cofactor as bait. We have recently developed a unique genome-oriented database search engine, Ariadne, which allows tandem MS-based identification of RNAs in biological samples. Thus, the method presented here has broad potential for automated analysis of RNA; it complements conventional molecular biology-based techniques and is particularly suited for simultaneous analysis of the composition, structure, interaction, and dynamics of RNA and protein components in various cellular RNP complexes.

  11. Microbial Reverse-Electrodialysis Electrolysis and Chemical-Production Cell for H2 Production and CO2 Sequestration.

    KAUST Repository

    Zhu, Xiuping; Hatzell, Marta C; Logan, Bruce E

    2014-01-01

    Natural mineral carbonation can be accelerated using acid and alkali solutions to enhance atmospheric CO2 sequestration, but the production of these solutions needs to be carbon-neutral. A microbial reverse-electrodialysis electrolysis and chemical-production cell (MRECC) was developed to produce these solutions and H2 gas using only renewable energy sources (organic matter and salinity gradient). Using acetate (0.82 g/L) as a fuel for microorganisms to generate electricity in the anode chamber (liquid volume of 28 mL), 0.45 mmol of acid and 1.09 mmol of alkali were produced at production efficiencies of 35% and 86%, respectively, along with 10 mL of H2 gas. Serpentine dissolution was enhanced 17-87-fold using the acid solution, with approximately 9 mL of CO2 absorbed and 4 mg of CO2 fixed as magnesium or calcium carbonates. The operational costs, based on mineral digging and grinding, and water pumping, were estimated to be only $25/metric ton of CO2 fixed as insoluble carbonates. Considering the additional economic benefits of H2 generation and possible wastewater treatment, this method may be a cost-effective and environmentally friendly method for CO2 sequestration.

  12. Online monitoring of N-nitrosodimethylamine rejection as a performance indicator of trace organic chemical removal by reverse osmosis.

    Science.gov (United States)

    Fujioka, Takahiro; Takeuchi, Haruka; Tanaka, Hiroaki; Kodamatani, Hitoshi

    2018-06-01

    The security of recycled water quality in potable reuse can be enhanced by improving the credibility of reverse osmosis (RO) treatment for the removal of trace organic chemicals (TOrCs). This study evaluated the potential of online monitoring of N-nitrosodimethylamine (NDMA) before and after RO treatment as a surrogate indicator for TOrC removal by RO. This pilot-scale study monitored NDMA concentrations in RO feedwater (ultrafiltration-treated wastewater) and RO permeate every 22 min using novel online NDMA analyzers-high-performance liquid chromatography followed by photochemical reaction and chemiluminescence detection. NDMA rejection by RO varied considerably in response to changes in operating conditions (permeate flux and feedwater temperature). A high linear correlation between NDMA rejection and the rejection of six other TOrCs was observed. The linear correlation was also identified for an RO membrane damaged with chlorine. The correlation between another potential surrogate indicator (conductivity rejection) and TOrC rejection was relatively low. NDMA, which is the smallest compound among regulated TOrCs, revealed rejections lower than the other TOrCs, indicating that NDMA rejection can be a conservative surrogate indicator capable of predicting changes in TOrC removal. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Microbial Reverse-Electrodialysis Electrolysis and Chemical-Production Cell for H2 Production and CO2 Sequestration.

    KAUST Repository

    Zhu, Xiuping

    2014-03-24

    Natural mineral carbonation can be accelerated using acid and alkali solutions to enhance atmospheric CO2 sequestration, but the production of these solutions needs to be carbon-neutral. A microbial reverse-electrodialysis electrolysis and chemical-production cell (MRECC) was developed to produce these solutions and H2 gas using only renewable energy sources (organic matter and salinity gradient). Using acetate (0.82 g/L) as a fuel for microorganisms to generate electricity in the anode chamber (liquid volume of 28 mL), 0.45 mmol of acid and 1.09 mmol of alkali were produced at production efficiencies of 35% and 86%, respectively, along with 10 mL of H2 gas. Serpentine dissolution was enhanced 17-87-fold using the acid solution, with approximately 9 mL of CO2 absorbed and 4 mg of CO2 fixed as magnesium or calcium carbonates. The operational costs, based on mineral digging and grinding, and water pumping, were estimated to be only $25/metric ton of CO2 fixed as insoluble carbonates. Considering the additional economic benefits of H2 generation and possible wastewater treatment, this method may be a cost-effective and environmentally friendly method for CO2 sequestration.

  14. Dectin-1 is essential for reverse transcytosis of glycosylated SIgA-antigen complexes by intestinal M cells.

    Directory of Open Access Journals (Sweden)

    Nicolas Rochereau

    2013-09-01

    Full Text Available Intestinal microfold (M cells possess a high transcytosis capacity and are able to transport a broad range of materials including particulate antigens, soluble macromolecules, and pathogens from the intestinal lumen to inductive sites of the mucosal immune system. M cells are also the primary pathway for delivery of secretory IgA (SIgA to the gut-associated lymphoid tissue. However, although the consequences of SIgA uptake by M cells are now well known and described, the mechanisms whereby SIgA is selectively bound and taken up remain poorly understood. Here we first demonstrate that both the Cα1 region and glycosylation, more particularly sialic acid residues, are involved in M cell-mediated reverse transcytosis. Second, we found that SIgA is taken up by M cells via the Dectin-1 receptor, with the possible involvement of Siglec-5 acting as a co-receptor. Third, we establish that transcytosed SIgA is taken up by mucosal CX3CR1⁺ dendritic cells (DCs via the DC-SIGN receptor. Fourth, we show that mucosal and systemic antibody responses against the HIV p24-SIgA complexes administered orally is strictly dependent on the expression of Dectin-1. Having deciphered the mechanisms leading to specific targeting of SIgA-based Ag complexes paves the way to the use of such a vehicle for mucosal vaccination against various infectious diseases.

  15. A systems engineering approach to manage the complexity in sustainable chemical product-process design

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    This paper provides a perspective on model-data based solution approaches for chemical product-process design, which consists of finding the identity of the candidate chemical product, designing the process that can sustainably manufacture it and verifying the performance of the product during...... framework can manage the complexity associated with product-process problems very efficiently. Three specific computer-aided tools (ICAS, Sustain-Pro and VPPDLab) have been presented and their applications to product-process design, highlighted....

  16. Mapping of Drug-like Chemical Universe with Reduced Complexity Molecular Frameworks.

    Science.gov (United States)

    Kontijevskis, Aleksejs

    2017-04-24

    The emergence of the DNA-encoded chemical libraries (DEL) field in the past decade has attracted the attention of the pharmaceutical industry as a powerful mechanism for the discovery of novel drug-like hits for various biological targets. Nuevolution Chemetics technology enables DNA-encoded synthesis of billions of chemically diverse drug-like small molecule compounds, and the efficient screening and optimization of these, facilitating effective identification of drug candidates at an unprecedented speed and scale. Although many approaches have been developed by the cheminformatics community for the analysis and visualization of drug-like chemical space, most of them are restricted to the analysis of a maximum of a few millions of compounds and cannot handle collections of 10 8 -10 12 compounds typical for DELs. To address this big chemical data challenge, we developed the Reduced Complexity Molecular Frameworks (RCMF) methodology as an abstract and very general way of representing chemical structures. By further introducing RCMF descriptors, we constructed a global framework map of drug-like chemical space and demonstrated how chemical space occupied by multi-million-member drug-like Chemetics DNA-encoded libraries and virtual combinatorial libraries with >10 12 members could be analyzed and mapped without a need for library enumeration. We further validate the approach by performing RCMF-based searches in a drug-like chemical universe and mapping Chemetics library selection outputs for LSD1 targets on a global framework chemical space map.

  17. Interconversion of η3-H2SiRR' σ-complexes and 16-electron silylene complexes via reversible H-H or C-H elimination.

    Science.gov (United States)

    Lipke, Mark C; Neumeyer, Felix; Tilley, T Don

    2014-04-23

    Solid samples of η(3)-silane complexes [PhBP(Ph)3]RuH(η(3)-H2SiRR') (R,R' = Et2, 1a; PhMe, 1b; Ph2, 1c, MeMes, 1d) decompose when exposed to dynamic vacuum. Gas-phase H2/D2 exchange between isolated, solid samples of 1c-d3 and 1c indicate that a reversible elimination of H2 is the first step in the irreversible decomposition. An efficient solution-phase trap for hydrogen, the 16-electron ruthenium benzyl complex [PhBP(Ph)3]Ru[η(3)-CH2(3,5-Me2C6H3)] (3) reacts quantitatively with H2 in benzene via elimination of mesitylene to form the η(5)-cyclohexadienyl complex [PhBP(Ph)3]Ru(η(5)-C6H7) (4). This H2 trapping reaction was utilized to drive forward and quantify the elimination of H2 from 1b,d in solution, which resulted in the decomposition of 1b,d to form 4 and several organosilicon products that could not be identified. Reaction of {[PhBP(Ph)3]Ru(μ-Cl)}2 (2) with (THF)2Li(SiHMes2) forms a new η(3)-H2Si species [PhBP(Ph)3]Ru[CH2(2-(η(3)-H2SiMes)-3,5-Me2C6H2)] (5) which reacts with H2 to form the η(3)-H2SiMes2 complex [PhBP(Ph)3]RuH(η(3)-H2SiMes2) (1e). Complex 1e was identified by NMR spectroscopy prior to its decomposition by elimination of Mes2SiH2 to form 4. DFT calculations indicate that an isomer of 5, the 16-electron silylene complex [PhBP(Ph)3]Ru(μ-H)(═SiMes2), is only 2 kcal/mol higher in energy than 5. Treatment of 5 with XylNC (Xyl = 2,6-dimethylphenyl) resulted in trapping of [PhBP(Ph)3]Ru(μ-H)(═SiMes2) to form the 18-electron silylene complex [PhBP(Ph)3]Ru(CNXyl)(μ-H)(═SiMes2) (6). A closely related germylene complex [PhBP(Ph)3]Ru[CN(2,6-diphenyl-4-MeC6H2)](H)(═GeH(t)Bu) (8) was prepared from reaction of (t)BuGeH3 with the benzyl complex [PhBP(Ph)3]Ru[CN(2,6-diphenyl-4-MeC6H2)][η(1)-CH2(3,5-Me2C6H3)] (7). Single crystal XRD analysis indicated that unlike for 6, the hydride ligand in 8 is a terminal hydride that does not engage in 3c-2e Ru-H → Ge bonding. Complex 1b is an effective precatalyst for the catalytic Ge-H dehydrocoupling

  18. Characterization of the pharmacokinetics of gasoline using PBPK modeling with a complex mixtures chemical lumping approach.

    Science.gov (United States)

    Dennison, James E; Andersen, Melvin E; Yang, Raymond S H

    2003-09-01

    Gasoline consists of a few toxicologically significant components and a large number of other hydrocarbons in a complex mixture. By using an integrated, physiologically based pharmacokinetic (PBPK) modeling and lumping approach, we have developed a method for characterizing the pharmacokinetics (PKs) of gasoline in rats. The PBPK model tracks selected target components (benzene, toluene, ethylbenzene, o-xylene [BTEX], and n-hexane) and a lumped chemical group representing all nontarget components, with competitive metabolic inhibition between all target compounds and the lumped chemical. PK data was acquired by performing gas uptake PK studies with male F344 rats in a closed chamber. Chamber air samples were analyzed every 10-20 min by gas chromatography/flame ionization detection and all nontarget chemicals were co-integrated. A four-compartment PBPK model with metabolic interactions was constructed using the BTEX, n-hexane, and lumped chemical data. Target chemical kinetic parameters were refined by studies with either the single chemical alone or with all five chemicals together. o-Xylene, at high concentrations, decreased alveolar ventilation, consistent with respiratory irritation. A six-chemical interaction model with the lumped chemical group was used to estimate lumped chemical partitioning and metabolic parameters for a winter blend of gasoline with methyl t-butyl ether and a summer blend without any oxygenate. Computer simulation results from this model matched well with experimental data from single chemical, five-chemical mixture, and the two blends of gasoline. The PBPK model analysis indicated that metabolism of individual components was inhibited up to 27% during the 6-h gas uptake experiments of gasoline exposures.

  19. The effect of chemical warfare on respiratory symptoms, pulmonary function tests and their reversibility 23-25 years after exposure.

    Science.gov (United States)

    Boskabady, Mrteza; Boskabady, Mohammad Hossein; Zabihi, Narges Amel; Boskabady, Marzie

    2015-01-01

    Pulmonary complications due to mustard gas exposure range from no effect to severe bronchial stenosis. Pulmonary function tests (PFTs) and respiratory symptoms in chemical war victims were studied 23-25 years after exposure to sulfur mustard (SM). Respiratory symptoms were evaluated in a sample of 142 chemical war victims and 120 control subjects with similar age from the general population using a questionnaire including questions on respiratory symptoms in the past year. PFT values were also measured in chemical war victims before and 15 min after the inhalation of 200 µg salbutamol and baseline PFT in controls. All chemical war victims (100%) reported respiratory symptoms. Wheezing (66.19%), cough (64.78%), and chest tightness (54.4%) were the most common symptoms and only 15.5% of chemical war victims reported sputum (p chemical war victims had wheeze in chest examination, which were significantly higher than control group (p chemical war victims than that in control subjects (p chemical war victims, 23-25 years after exposure to chemical warfare have higher frequencies and severity of respiratory symptoms. PFT values were also significantly reduced among chemical war victims, which showed reversibility due to the inhalation of 200 µg salbutamol. © The Author(s) 2012.

  20. Chemical approach to neutral-ionic valence instability, quantum phase transition, and relaxor ferroelectricity in organic charge-transfer complexes

    International Nuclear Information System (INIS)

    Horiuchi, Sachio; Kumai, Reiji; Okimoto, Yoichi; Tokura, Yoshinori

    2006-01-01

    Neutral-ionic (NI) phase transition is a reversible switching of organic charge-transfer complexes between distinct valence states by external stimuli. This phase transformation in the low-dimensional system is demonstrated to provide a variety of novel dielectric, structural, and electronic properties. Importantly, ionization of the electron donor-acceptor pairs is usually accompanied by a ferroelectric or antiferroelectric order of the molecular lattice, leading to huge dielectric response near the transition point. Although these characteristics are potentially useful for future electronic and optical applications, the thermally accessible NI transition (TINIT) is still an extremely rare case. The TINIT compounds including some new materials are overviewed in order to provide convenient guides to their design and experimental identifications. The phase transition and dielectric properties can be closely controlled in various ways depending on chemical and physical modifications of the crystals. Among them, a quantum phase transition and relaxor ferroelectricity, both of which are currently attracting subjects from both scientific and practical perspectives, are highlighted as the first achievements in organic charge-transfer complexes

  1. Micro-oxygenation does not eliminate hydrogen sulfide and mercaptans from wine; it simply shifts redox and complex-related equilibria to reversible oxidized species and complexed forms.

    Science.gov (United States)

    Vela, Eduardo; Hernandez-Orte, Purificación; Franco-Luesma, Ernesto; Ferreira, Vicente

    2018-03-15

    This work seeks to assess the effects of micro-oxygenation (MOX) on the present and potential levels of Volatile Sulfur Compounds (VSCs) of wine. With such purpose, three red wines with a tendency to develop sulfury off-odors were subjected to three different MOX conditions (4.4-20mg/L delivered at 0.05 or 0.2mg/L/day). Samples were further subjected to Accelerated Reductive aging (AR) and analyzed for free and Brine Releasable (BR) VSCs and redox potential. Although MOX induced strong decreases in the levels of all free VSCs, hardly affected the ability of the wine to release back hydrogen sulfide and other mercaptans during AR-aging. During aging BR-levels of MOX samples became in most cases similar or higher than non-oxygenated controls. BR-levels and the fractions free/BR follow characteristic sigmoid plots when represented versus redox potential suggesting that all changes are the result of reversible equilibria between free, metal-complexed and oxidized forms of VSCs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Comparison of three-factor and four-factor prothrombin complex concentrates regarding reversal of the anticoagulant effects of rivaroxaban in healthy volunteers

    NARCIS (Netherlands)

    Levi, M. [=Marcel M.; Moore, K. T.; Castillejos, C. F.; Kubitza, D.; Berkowitz, S. D.; Goldhaber, S. Z.; Raghoebar, M.; Patel, M. R.; Weitz, J. I.; Levy, J. H.

    2014-01-01

    Four-factor prothrombin complex concentrates (PCCs), which contain factor II, FVII, FIX, and FX, have shown the potential to reverse the anticoagulant effect of rivaroxaban in healthy volunteers. The purpose of this study was to determine whether a three-factor PCC, which contains little FVII, has a

  3. Complete relaxation and conformational exchange matrix (CORCEMA) analysis of intermolecular saturation transfer effects in reversibly forming ligand-receptor complexes.

    Science.gov (United States)

    Jayalakshmi, V; Krishna, N Rama

    2002-03-01

    A couple of recent applications of intermolecular NOE (INOE) experiments as applied to biomolecular systems involve the (i) saturation transfer difference NMR (STD-NMR) method and (ii) the intermolecular cross-saturation NMR (ICS-NMR) experiment. STD-NMR is a promising tool for rapid screening of a large library of compounds to identify bioactive ligands binding to a target protein. Additionally, it is also useful in mapping the binding epitopes presented by a bioactive ligand to its target protein. In this latter application, the STD-NMR technique is essentially similar to the ICS-NMR experiment, which is used to map protein-protein or protein-nucleic acid contact surfaces in complexes. In this work, we present a complete relaxation and conformational exchange matrix (CORCEMA) theory (H. N. B. Moseley et al., J. Magn. Reson. B 108, 243-261 (1995)) applicable for these two closely related experiments. As in our previous work, we show that when exchange is fast on the relaxation rate scale, a simplified CORCEMA theory can be formulated using a generalized average relaxation rate matrix. Its range of validity is established by comparing its predictions with those of the exact CORCEMA theory which is valid for all exchange rates. Using some ideal model systems we have analyzed the factors that influence the ligand proton intensity changes when the resonances from some protons on the receptor protein are saturated. The results show that the intensity changes in the ligand signals in an intermolecular NOE experiment are very much dependent upon: (1) the saturation time, (2) the location of the saturated receptor protons with respect to the ligand protons, (3) the conformation of the ligand-receptor interface, (4) the rotational correlation times for the molecular species, (5) the kinetics of the reversibly forming complex, and (6) the ligand/receptor ratio. As an example of a typical application of the STD-NMR experiment we have also simulated the STD effects for a

  4. Widespread distribution of archaeal reverse gyrase in thermophilic bacteria suggests a complex history of vertical inheritance and lateral gene transfers

    Directory of Open Access Journals (Sweden)

    Céline Brochier-Armanet

    2006-01-01

    Full Text Available Reverse gyrase, an enzyme of uncertain funtion, is present in all hyperthermophilic archaea and bacteria. Previous phylogenetic studies have suggested that the gene for reverse gyrase has an archaeal origin and was transferred laterally (LGT to the ancestors of the two bacterial hyperthermophilic phyla, Thermotogales and Aquificales. Here, we performed an in-depth analysis of the evolutionary history of reverse gyrase in light of genomic progress. We found genes coding for reverse gyrase in the genomes of several thermophilic bacteria that belong to phyla other than Aquificales and Thermotogales. Several of these bacteria are not, strictly speaking, hyperthermophiles because their reported optimal growth temperatures are below 80 °C. Furthermore, we detected a reverse gyrase gene in the sequence of the large plasmid of Thermus thermophilus strain HB8, suggesting a possible mechanism of transfer to the T. thermophilus strain HB8 involving plasmids and transposases. The archaeal part of the reverse gyrase tree is congruent with recent phylogenies of the archaeal domain based on ribosomal proteins or RNA polymerase subunits. Although poorly resolved, the complete reverse gyrase phylogeny suggests an ancient acquisition of the gene by bacteria via one or two LGT events, followed by its secondary distribution by LGT within bacteria. Finally, several genes of archaeal origin located in proximity to the reverse gyrase gene in bacterial genomes have bacterial homologues mostly in thermophiles or hyperthermophiles, raising the possibility that they were co-transferred with the reverse gyrase gene. Our new analysis of the reverse gyrase history strengthens the hypothesis that the acquisition of reverse gyrase may have been a crucial evolutionary step in the adaptation of bacteria to high-temperature environments. However, it also questions the role of this enzyme in thermophilic bacteria and the selective advantage its presence could provide.

  5. Widespread distribution of archaeal reverse gyrase in thermophilic bacteria suggests a complex history of vertical inheritance and lateral gene transfers.

    Science.gov (United States)

    Brochier-Armanet, Céline; Forterre, Patrick

    2007-05-01

    Reverse gyrase, an enzyme of uncertain funtion, is present in all hyperthermophilic archaea and bacteria. Previous phylogenetic studies have suggested that the gene for reverse gyrase has an archaeal origin and was transferred laterally (LGT) to the ancestors of the two bacterial hyperthermophilic phyla, Thermotogales and Aquificales. Here, we performed an in-depth analysis of the evolutionary history of reverse gyrase in light of genomic progress. We found genes coding for reverse gyrase in the genomes of several thermophilic bacteria that belong to phyla other than Aquificales and Thermotogales. Several of these bacteria are not, strictly speaking, hyperthermophiles because their reported optimal growth temperatures are below 80 degrees C. Furthermore, we detected a reverse gyrase gene in the sequence of the large plasmid of Thermus thermophilus strain HB8, suggesting a possible mechanism of transfer to the T. thermophilus strain HB8 involving plasmids and transposases. The archaeal part of the reverse gyrase tree is congruent with recent phylogenies of the archaeal domain based on ribosomal proteins or RNA polymerase subunits. Although poorly resolved, the complete reverse gyrase phylogeny suggests an ancient acquisition of the gene by bacteria via one or two LGT events, followed by its secondary distribution by LGT within bacteria. Finally, several genes of archaeal origin located in proximity to the reverse gyrase gene in bacterial genomes have bacterial homologues mostly in thermophiles or hyperthermophiles, raising the possibility that they were co-transferred with the reverse gyrase gene. Our new analysis of the reverse gyrase history strengthens the hypothesis that the acquisition of reverse gyrase may have been a crucial evolutionary step in the adaptation of bacteria to high-temperature environments. However, it also questions the role of this enzyme in thermophilic bacteria and the selective advantage its presence could provide.

  6. Moessbauer spectroscopy-nuclear hyperfine technique for studying dynamic chemical states of iron complexes

    International Nuclear Information System (INIS)

    Maeda, Y.

    2005-01-01

    A brief introduction of Moessbauer spectroscopy will be presented, followed by a discussion of the Moessbauer parameters, isomer shifts, quadrupole splittings, and spectral shapes of complexes in the presence of relaxation of the electronic states of the iron atoms. The usefulness of Moessbauer spectroscopy to demonstrate the dynamic phenomena of electronic states will be discussed in this lecture. (1) The Moessbauer spectra of mixed valence dinuclear and trinuclear iron complexes will be discussed in connection with the chemical structure of the complexes: The values of the quadrupole splittings and isomer shifts of [Fe II Fe III (bpmp) (ppa) 2 ](BF 4 ) 2 increase on raising the temperature, where Hbpmp represents 2,6-bis[bis(2- pyridylmethyl)aminoethyl]-4-methylphenol and ppa is 3-n-phenylpropionic acid. The spectra can be accounted for by postulating intramolecular electron exchange between two energetically inequivalent vibronic states Fe A 2+ Fe B 3+ and Fe A 3+ Fe B 2+ : The apparent time averaged valence states of the iron atoms are 2.2 and 2.8 on the Moessbauer time scale at 293 K. (2) The Moessbauer spectra of iron(III) spin-crossover complexes will be discussed in connection with the spin-transition rate and chemical structure of the complexes. The Moessbauer spectra of spin-crossover iron(III) complexes with LIESST (Light Induced Electronic Spin-State Transition) and of metallomesogens will be discussed to illustrate the extension of this research area by the use of Moessbauer spectroscopy.

  7. On improved understanding of plasma-chemical processes in complex low-temperature plasmas

    Science.gov (United States)

    Röpcke, Jürgen; Loffhagen, Detlef; von Wahl, Eric; Nave, Andy S. C.; Hamann, Stephan; van Helden, Jean-Piere H.; Lang, Norbert; Kersten, Holger

    2018-05-01

    Over the last years, chemical sensing using optical emission spectroscopy (OES) in the visible spectral range has been combined with methods of mid infrared laser absorption spectroscopy (MIR-LAS) in the molecular fingerprint region from 3 to 20 μm, which contains strong rotational-vibrational absorption bands of a large variety of gaseous species. This optical approach established powerful in situ diagnostic tools to study plasma-chemical processes of complex low-temperature plasmas. The methods of MIR-LAS enable to detect stable and transient molecular species in ground and excited states and to measure the concentrations and temperatures of reactive species in plasmas. Since kinetic processes are inherent to discharges ignited in molecular gases, high time resolution on sub-second timescales is frequently desired for fundamental studies as well as for process monitoring in applied research and industry. In addition to high sensitivity and good temporal resolution, the capacity for broad spectral coverage enabling multicomponent detection is further expanding the use of OES and MIR-LAS techniques. Based on selected examples, this paper reports on recent achievements in the understanding of complex low-temperature plasmas. Recently, a link with chemical modeling of the plasma has been provided, which is the ultimate objective for a better understanding of the chemical and reaction kinetic processes occurring in the plasma. Contribution to the Topical Issue "Fundamentals of Complex Plasmas", edited by Jürgen Meichsner, Michael Bonitz, Holger Fehske, Alexander Piel.

  8. Physico-Chemical and In-vitro Microbial Studies of Newly Synthesis Organometallic Complexes

    Directory of Open Access Journals (Sweden)

    Isam Hussain Al-Karkhi

    2014-05-01

    Full Text Available Drugs normally synthesized to use as medication to treat diseases like cancer and microbial infections, these synthesized drugs were interested more than naturally-derived drugs which have been shows low activity or not as efficient against diseases. A new ligand 3-methylbenzyl (2Z-2-[1-(pyridin-4-ylethylidene]hydrazine carbodithioate (PE3MBC and its Cd(II, Cu(II, Co(II and Zn(II metal complexes. The new ligand and metal complexes were characterized via various physico-chemical and spectroscopic techniques. Cd(II complex show more activity against microbes and against cancer cell line MCF-7, while other complexes does not shows activity like cadmium complex, all the complexes does not shows any activity against MDAMB-231 cell line. The fatal of the cancer and the microbes cell was due to inhibition of DNA synthesis which was probably due to chelating with metals complexes, or could be referred to lipophilicity, presence of hydrophobic moiety in the complex molecule, also could be due to steric effects and electronic effects.

  9. Chemical reactivity of analogous technetium(V) and rhenium(V) dioxo complexes

    International Nuclear Information System (INIS)

    Kremer, C.; Kremer, E.; Leon, A.

    1993-01-01

    All complexes of the series [MO 2 L 2 ] + (M = Tc, Re, L = ethylenediamine (en), 1,3-diaminopropane (1,3-dap)) have been synthesized and their chemical reactivities investigated. The following properties were studied: stability of the aqueous solutions at different pH values, substitution kinetics, lipophilicity and protein binding. The complexes show very similar reactivity in aqueous solution. From a radiopharmaceutical point of view, no significant difference in their in vivo behavior is expected. (author) 12 refs.; 1 fig.; 3 tabs

  10. Directed assembly of functional light harvesting antenna complexes onto chemically patterned surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Escalante, Maryana [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Maury, Pascale [Molecular Nanofabrication Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Bruinink, Christiaan M [Molecular Nanofabrication Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Werf, Kees van der [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Olsen, John D [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom); Timney, John A [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom); Huskens, Jurriaan [Molecular Nanofabrication Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hunter, C Neil [Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN (United Kingdom); Subramaniam, Vinod [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Otto, Cees [Biophysical Engineering Group, MESA and Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands)

    2008-01-16

    We report the directed assembly of the photosynthetic membrane proteins LH1 and LH2 isolated from the purple bacterium Rhodobacter sphaeroides onto chemically patterned substrates. Nanoimprint lithography was used to pattern discrete regions of amino- and fluoro-terminated or poly(ethylene glycol) self-assembled monolayers onto a glass substrate. Densely packed layers of assembled protein complexes were observed with atomic force microscopy. The protein complexes attached selectively to the amino-terminated regions by electrostatic interactions. Spectral images generated with a hybrid scanning probe and fluorescence microscope confirmed that the patterned proteins retained their native optical signatures.

  11. Study of chemical shifts of the chloroform complexes with cyclic donors of electrons

    International Nuclear Information System (INIS)

    Blaszkiewicz, B.; Pajak, Z.

    1973-01-01

    Chemical shifts of chloroform complexes with the heterocyclic electron donors: pyridine, piperidine, alpha-picoline and gamma-picoline have been studied using the high resolution (5.10 -9 ) spectrometer operating at 80 MHz. An attempt has also been made to study the three - component solutions of : chloroform, a heterocyclic donor of electrons and carbon tetrachloride. The results, which have been obtained, indicate that the complex-forming power of pyridine and other electron donors is greater in carbon tetrachloride than in other solvents. (S.B.)

  12. Directed assembly of functional light harvesting antenna complexes onto chemically patterned surfaces

    International Nuclear Information System (INIS)

    Escalante, Maryana; Maury, Pascale; Bruinink, Christiaan M; Werf, Kees van der; Olsen, John D; Timney, John A; Huskens, Jurriaan; Hunter, C Neil; Subramaniam, Vinod; Otto, Cees

    2008-01-01

    We report the directed assembly of the photosynthetic membrane proteins LH1 and LH2 isolated from the purple bacterium Rhodobacter sphaeroides onto chemically patterned substrates. Nanoimprint lithography was used to pattern discrete regions of amino- and fluoro-terminated or poly(ethylene glycol) self-assembled monolayers onto a glass substrate. Densely packed layers of assembled protein complexes were observed with atomic force microscopy. The protein complexes attached selectively to the amino-terminated regions by electrostatic interactions. Spectral images generated with a hybrid scanning probe and fluorescence microscope confirmed that the patterned proteins retained their native optical signatures

  13. Using Tc-Re chemical analogy to synthesize and identify new 99mTc complexes

    International Nuclear Information System (INIS)

    Gambino, D.; Kremer, C.; Cartesio, S.; Leon, A.; Kremer, E.

    1989-01-01

    The strong chemical resemblance between Tc and Re is applied to design and evaluate experiments with 99m Tc complexes. A combination of spectrophotometric and electrophoretic techniques allows to propose the formula [TcO 2 (amine) 2 ] + for compounds prepared by reduction of 99m TcO 4 - with Zn (solid phase) in presence of several (bidentate) amines. (author) 10 refs.; 2 figs.; 4 tabs

  14. A large scale analysis of information-theoretic network complexity measures using chemical structures.

    Directory of Open Access Journals (Sweden)

    Matthias Dehmer

    Full Text Available This paper aims to investigate information-theoretic network complexity measures which have already been intensely used in mathematical- and medicinal chemistry including drug design. Numerous such measures have been developed so far but many of them lack a meaningful interpretation, e.g., we want to examine which kind of structural information they detect. Therefore, our main contribution is to shed light on the relatedness between some selected information measures for graphs by performing a large scale analysis using chemical networks. Starting from several sets containing real and synthetic chemical structures represented by graphs, we study the relatedness between a classical (partition-based complexity measure called the topological information content of a graph and some others inferred by a different paradigm leading to partition-independent measures. Moreover, we evaluate the uniqueness of network complexity measures numerically. Generally, a high uniqueness is an important and desirable property when designing novel topological descriptors having the potential to be applied to large chemical databases.

  15. A composite of complex and chemical hydrides yields the first Al-based amidoborane with improved hydrogen storage properties.

    Science.gov (United States)

    Dovgaliuk, Iurii; Jepsen, Lars H; Safin, Damir A; Łodziana, Zbigniew; Dyadkin, Vadim; Jensen, Torben R; Devillers, Michel; Filinchuk, Yaroslav

    2015-10-05

    The first Al-based amidoborane Na[Al(NH2 BH3 )4 ] was obtained through a mechanochemical treatment of the NaAlH4 -4 AB (AB=NH3 BH3 ) composite releasing 4.5 wt % of pure hydrogen. The same amidoborane was also produced upon heating the composite at 70 °C. The crystal structure of Na[Al(NH2 BH3 )4 ], elucidated from synchrotron X-ray powder diffraction and confirmed by DFT calculations, contains the previously unknown tetrahedral ion [Al(NH2 BH3 )4 ](-) , with every NH2 BH3 (-) ligand coordinated to aluminum through nitrogen atoms. Combination of complex and chemical hydrides in the same compound was possible due to both the lower stability of the AlH bonds compared to the BH ones in borohydride, and due to the strong Lewis acidity of Al(3+) . According to the thermogravimetric analysis-differential scanning calorimetry-mass spectrometry (TGA-DSC-MS) studies, Na[Al(NH2 BH3 )4 ] releases in two steps 9 wt % of pure hydrogen. As a result of this decomposition, which was also supported by volumetric studies, the formation of NaBH4 and amorphous product(s) of the surmised composition AlN4 B3 H(0-3.6) were observed. Furthermore, volumetric experiments have also shown that the final residue can reversibly absorb about 27 % of the released hydrogen at 250 °C and p(H2 )=150 bar. Hydrogen re-absorption does not regenerate neither Na[Al(NH2 BH3 )4 ] nor starting materials, NaAlH4 and AB, but rather occurs within amorphous product(s). Detailed studies of the latter one(s) can open an avenue for a new family of reversible hydrogen storage materials. Finally, the NaAlH4 -4 AB composite might become a starting point towards a new series of aluminum-based tetraamidoboranes with improved hydrogen storage properties such as hydrogen storage density, hydrogen purity, and reversibility. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Half-sandwich cobalt complexes in the metal-organic chemical vapor deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Georgi, Colin [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Hapke, Marko; Thiel, Indre [Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Albert-Einstein-Straße 29a, Rostock 18059 (Germany); Hildebrandt, Alexander [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Waechtler, Thomas; Schulz, Stefan E. [Fraunhofer Institute of Electronic Nano Systems (ENAS), Technologie-Campus 3, Chemnitz 09126 (Germany); Technische Universität Chemnitz, Center for Microtechnologies (ZfM), Chemnitz 09107 (Germany); Lang, Heinrich, E-mail: heinrich.lang@chemie.tu-chemnitz.de [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany)

    2015-03-02

    A series of cobalt half-sandwich complexes of type [Co(η{sup 5}-C{sub 5}H{sub 5})(L)(L′)] (1: L, L′ = 1,5-hexadiene; 2: L = P(OEt){sub 3}, L′ = H{sub 2}C=CHSiMe{sub 3}; 3: L = L′ = P(OEt){sub 3}) has been studied regarding their physical properties such as the vapor pressure, decomposition temperature and applicability within the metal-organic chemical vapor deposition (MOCVD) process, with a focus of the influence of the phosphite ligands. It could be shown that an increasing number of P(OEt){sub 3} ligands increases the vapor pressure and thermal stability of the respective organometallic compound. Complex 3 appeared to be a promising MOCVD precursor with a high vapor pressure and hence was deposited onto Si/SiO{sub 2} (100 nm) substrates. The resulting reflective layer is closed, dense and homogeneous, with a slightly granulated surface morphology. X-ray photoelectron spectroscopy (XPS) studies demonstrated the formation of metallic cobalt, cobalt phosphate, cobalt oxide and cobalt carbide. - Highlights: • Thermal studies and vapor pressure measurements of cobalt half-sandwich complexes was carried out. • Chemical vapor deposition with cobalt half-sandwich complexes is reported. • The use of Co-phosphites results in significant phosphorous-doped metallic layers.

  17. Chemical diversity and antileishmanial activity of crude extracts of Laurencia complex (Ceramiales, Rhodophyta from Brazil

    Directory of Open Access Journals (Sweden)

    Fernanda L. da S. Machado

    Full Text Available Chemical profiles of extracts of four species from Laurencia complex (Ceramiales, Rhodophyta from different populations collected along Southeast Brazilian coast were assessed by High Performance Liquid Chromatography coupled with a Diode Array Detector in order to observe geographic chemical variability. Aiming to evaluate the impact of chemical diversity on potential pharmaceutical uses, the extracts were tested against the promastigote form of Leishmania amazonensis. The most active extracts were submitted to anti-amastigote and cytotoxicity assays. Principal Component Analysis of the chromatograms resulted in four major groups of chemical profiles according to the presence of leishmanicidal chamigranes (--elatol and obtusol. The existence of chemotypes, displaying variable pharmacological action, is proposed for the differences observed in L. dendroidea samples. Although all extracts were found active against promastigote form of L. amazonensis, their efficacy was remarkably different and not related to the variation of (--elatol and obtusol, which indicates the presence of additional compounds with antileishmanial activity. Moreover, the active extracts also displayed anti-amastigote activity and none of them were considered cytotoxic. The results highlight that the knowledge of chemical geographic variability can be valuable in the search of new antileishmanial compounds from marine sources.

  18. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  19. Binding Constant of Amines to Water/AOT/n-Hexene Reverse Micelles. Influence of the Chemical Structure

    Directory of Open Access Journals (Sweden)

    J. J. Silber

    2000-03-01

    Full Text Available The distribution of different amines between n-hexane bulk and the micellar pseudophase of AOT reverse micelles were measured by a fluorometric method. An independent method was used to corroborate the incorporation of the amines to the interface. The effect of the amine structure on the binding constant was analysed.

  20. SIMULTANEOUS ABSORPTION AND DESORPTION WITH REVERSIBLE 1ST-ORDER CHEMICAL-REACTION - ANALYTICAL SOLUTION AND NEGATIVE ENHANCEMENT FACTORS

    NARCIS (Netherlands)

    WINKELMAN, JGM; BEENACKERS, AACM

    The problem of ps absorption accompanied by a first-order reversible reaction, producing a volatile reaction product, is considered. A general analytical solution is developed for the film model, resulting in explicit relations for the concentration profiles in the film and for the mass transfer

  1. Technical-economic parameters of the new oil shale mining-chemical complex in Northeast Estonia

    International Nuclear Information System (INIS)

    Kuzmiv, I.; Fraiman, J.

    2006-01-01

    The history of oil shale mining in Estonia has reached its century mark. Three oil shale branches have been formed and have been working on the basis of Estonian oil shale deposits: the mining industry (underground and surface extraction), the power industry (heat and electric energy generation), and the chemical industry (gas and synthetic oils). The authors attempted to summarize the experience of the activities of these branches and to make into a whole the results of their research developments in the past years, as well as to form a notion about perspectives of oil shale in Estonia. Variants of the mining-chemical oil shale complex production and trade patterns differed from used ones. Mining methods, thermal processing of oil shale, and solid, liquid, and gas waste recovery have been studied, analyzed, and worked out up to the present. Setting up a flexible trade structure within the framework of that complex is considered the main economic mechanism capable of balancing production costs of such a complex with its earnings, which could respond properly to any, even peak, fluctuations of the market for final products processed from oil shale. Data of the working 'Estonia' oil shale mine were used as the basis of the analysis and practical conclusions. Information on the mine being projected in the region of Ojamaa in the northeast of Estonia was taken as the data of the worthwhile supplier. Oil shale processing chemical complex is considered in two structural alternatives: in technological chain with the 'Estonia' mine (the first variant), and the projected mine of a new technical level (the second variant). (author)

  2. Neptunium carbonato complexes in aqueous solution: an electrochemical, spectroscopic, and quantum chemical study.

    Science.gov (United States)

    Ikeda-Ohno, Atsushi; Tsushima, Satoru; Takao, Koichiro; Rossberg, André; Funke, Harald; Scheinost, Andreas C; Bernhard, Gert; Yaita, Tsuyoshi; Hennig, Christoph

    2009-12-21

    The electrochemical behavior and complex structure of Np carbonato complexes, which are of major concern for the geological disposal of radioactive wastes, have been investigated in aqueous Na(2)CO(3) and Na(2)CO(3)/NaOH solutions at different oxidation states by using cyclic voltammetry, X-ray absorption spectroscopy, and density functional theory calculations. The end-member complexes of penta- and hexavalent Np in 1.5 M Na(2)CO(3) with pH = 11.7 have been determined as a transdioxo neptunyl tricarbonato complex, [NpO(2)(CO(3))(3)](n-) (n = 5 for Np(V), and 4 for Np(VI)). Hence, the electrochemical reaction of the Np(V/VI) redox couple merely results in the shortening/lengthening of bond distances mainly because of the change of the cationic charge of Np, without any structural rearrangement. This explains the observed reversible-like feature on their cyclic voltammograms. In contrast, the electrochemical oxidation of Np(V) in a highly basic carbonate solution of 2.0 M Na(2)CO(3)/1.0 M NaOH (pH > 13) yielded a stable heptavalent Np complex of [Np(VII)O(4)(OH)(2)](3-), indicating that the oxidation reaction from Np(V) to Np(VII) in the carbonate solution involves a drastic structural rearrangement from the transdioxo configuration to a square-planar-tetraoxo configuration, as well as exchanging the coordinating anions from carbonate ions (CO(3)(2-)) to hydroxide ions (OH(-)).

  3. A 3D QSAR pharmacophore model and quantum chemical structure--activity analysis of chloroquine(CQ)-resistance reversal.

    Science.gov (United States)

    Bhattacharjee, Apurba K; Kyle, Dennis E; Vennerstrom, Jonathan L; Milhous, Wilbur K

    2002-01-01

    Using CATALYST, a three-dimensional QSAR pharmacophore model for chloroquine(CQ)-resistance reversal was developed from a training set of 17 compounds. These included imipramine (1), desipramine (2), and 15 of their analogues (3-17), some of which fully reversed CQ-resistance, while others were without effect. The generated pharmacophore model indicates that two aromatic hydrophobic interaction sites on the tricyclic ring and a hydrogen bond acceptor (lipid) site at the side chain, preferably on a nitrogen atom, are necessary for potent activity. Stereoelectronic properties calculated by using AM1 semiempirical calculations were consistent with the model, particularly the electrostatic potential profiles characterized by a localized negative potential region by the side chain nitrogen atom and a large region covering the aromatic ring. The calculated data further revealed that aminoalkyl substitution at the N5-position of the heterocycle and a secondary or tertiary aliphatic aminoalkyl nitrogen atom with a two or three carbon bridge to the heteroaromatic nitrogen (N5) are required for potent "resistance reversal activity". Lowest energy conformers for 1-17 were determined and optimized to afford stereoelectronic properties such as molecular orbital energies, electrostatic potentials, atomic charges, proton affinities, octanol-water partition coefficients (log P), and structural parameters. For 1-17, fairly good correlation exists between resistance reversal activity and intrinsic basicity of the nitrogen atom at the tricyclic ring system, frontier orbital energies, and lipophilicity. Significantly, nine out of 11 of a group of structurally diverse CQ-resistance reversal agents mapped very well on the 3D QSAR pharmacophore model.

  4. Synthesis of Fischer carbene complexes of iridium by C-H bond activation of methyl and cyclic ethers: Evidence for reversible {alpha}-hydrogen migration

    Energy Technology Data Exchange (ETDEWEB)

    Luecke, H.F.; Arndtsen, B.A.; Burger, P.; Bergman, R.G. [Lawrence Berkeley Lab., CA (United States)]|[Univ. of California, Berkeley, CA (United States)

    1996-03-13

    We report here a mild and versatile route to Fischer carbene complexes of iridium via the activation of C-H bonds of methyl and cyclic ethers, along with our preliminary studies of this rare family of carbene complexes. Theoretical studies suggest that {alpha}-hydrogen migrations can be kinetically favorable if a coordinatively unsaturated species can be accessed. Thus, the lability of the triflate ligand presumably facilitates this process. Further evidence for the rapidity, as well as reversibility, of this rearrangement was obtained by NMR analysis. 20 refs.

  5. A Retrospective Propensity Score-Matched Early Thromboembolic Event Analysis of Prothrombin Complex Concentrate vs Fresh Frozen Plasma for Warfarin Reversal Prior to Emergency Neurosurgical Procedures.

    Science.gov (United States)

    Agarwal, Prateek; Abdullah, Kalil G; Ramayya, Ashwin G; Nayak, Nikhil R; Lucas, Timothy H

    2017-06-29

    Reversal of therapeutic anticoagulation prior to emergency neurosurgical procedures is required in the setting of intracranial hemorrhage. Multifactor prothrombin complex concentrate (PCC) promises rapid efficacy but may increase the probability of thrombotic complications compared to fresh frozen plasma (FFP). To compare the rate of thrombotic complications in patients treated with PCC or FFP to reverse therapeutic anticoagulation prior to emergency neurosurgical procedures in the setting of intracranial hemorrhage at a level I trauma center. Sixty-three consecutive patients on warfarin therapy presenting with intracranial hemorrhage who received anticoagulation reversal prior to emergency neurosurgical procedures were retrospectively identified between 2007 and 2016. They were divided into 2 cohorts based on reversal agent, either PCC (n = 28) or FFP (n = 35). The thrombotic complications rates within 72 h of reversal were compared using the χ 2 test. A multivariate propensity score matching analysis was used to limit the threat to interval validity from selection bias arising from differences in demographics, laboratory values, history, and clinical status. Thrombotic complications were uncommon in this neurosurgical population, occurring in 1.59% (1/63) of treated patients. There was no significant difference in the thrombotic complication rate between groups, 3.57% (1/28; PCC group) vs 0% (0/35; FFP group). Propensity score matching analysis validated this finding after controlling for any selection bias. In this limited sample, thrombotic complication rates were similar between use of PCC and FFP for anticoagulation reversal in the management of intracranial hemorrhage prior to emergency neurosurgical procedures. Copyright © 2017 by the Congress of Neurological Surgeons

  6. Study to determine the technical and economic feasibility of reclaiming chemicals used in micellar polymer and low tension surfactant flooding. Final report. [Ultrafiltration membranes and reverse osmosis membranes

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, R.H.; Himmelblau, A.; Donnelly, R.G.

    1978-02-01

    Energy Resources Company has developed a technology for use with enhanced oil recovery to achieve emulsion breaking and surfactant recovery. By using ultrafiltration membranes, the Energy Resources Company process can dewater an oil-in-water type emulsion expected from enhanced oil recovery projects to the point where the emulsion can be inverted and treated using conventional emulsion-treating equipment. By using a tight ultrafiltration membrane or a reverse osmosis membrane, the Energy Resources Company process is capable of recovering chemicals such as surfactants used in micellar polymer flooding.

  7. Complexing agents and pH influence on chemical durability of type I moulded glass containers.

    Science.gov (United States)

    Biavati, Alberto; Poncini, Michele; Ferrarini, Arianna; Favaro, Nicola; Scarpa, Martina; Vallotto, Marta

    2017-06-16

    Among the factors that affect the glass surface chemical durability, pH and complexing agents presence in aqueous solution have the main role (1). Glass surface attack can be also related to the delamination issue with glass particles appearance in the pharmaceutical preparation. A few methods to check for glass containers delamination propensity and some control guidelines have been proposed (2,3). The present study emphasizes the possible synergy between a few complexing agents with pH on the borosilicate glass chemical durability. Hydrolytic attack was performed in small volume 23 ml type I glass containers autoclaved according to EP or USP for 1 hour at 121°C, in order to enhance the chemical attack due to time, temperature and the unfavourable surface/volume ratio. 0,048 M or 0.024 M (moles/liter) solutions of the acids citric, glutaric, acetic, EDTA (ethylenediaminetetraacetic acid) and sodium phosphate with water for comparison, were used for the trials. The pH was adjusted ± 0,05 units at fixed values 5,5-6,6-7-7,4-8-9 by LiOH diluted solution. Since silicon is the main glass network former, silicon release into the attack solutions was chosen as the main index of the glass surface attack and analysed by ICPAES. The work was completed by the analysis of the silicon release in the worst attack conditions, of moulded glass, soda lime type II and tubing borosilicate glass vials to compare different glass compositions and forming technologies. Surface analysis by SEM was finally performed to check for the surface status after the worst chemical attack condition by citric acid. Copyright © 2017, Parenteral Drug Association.

  8. Status of chemical elements in Atlantic Forest tree species near an industrial complex

    International Nuclear Information System (INIS)

    Araujo, A.L.L.; Fernandes, E.A.N.; Franca, E.J.; Bacchi, M.A.

    2008-01-01

    Environmental quality assessment studies have been conducted with tree species largely distributed in the Atlantic Forest. Leaf and soil samples were collected in the conservation unit Parque Estadual da Serra do Mar (PESM) nearby the industrial complex of Cubatao, Sao Paulo State, Brazil, and analyzed for chemical elements by instrumental neutron activation analysis. Results were compared to background values obtained in the Parque Estadual Carlos Botelho (PECB). The higher As, Fe, Hg and Zn mass fractions in the tree leaves of PESM indicated anthropogenic influence on this conservation unit. (author)

  9. Reduction of uranyl carbonate and hydroxyl complexes and neptunyl carbonate complexes studied with chemical-electrochemical methods and rixs spectroscopy

    International Nuclear Information System (INIS)

    Butorin, Sergei; Nordgren, Joseph; Ollila, Kaija; Albinsson, Yngve; Werme, Lars

    2003-10-01

    actinides have been mobilised through oxidation, they can migrate away from this potentially oxidising region and will encounter an oxygen free, reducing environment caused by the anaerobic corrosion of the cast iron insert. The actinyl species are no longer thermodynamically stable and reduction to the tetravalent state will be possible. There is, however, an open question whether the reduction kinetics will be sufficiently high to cause reduction in solution and if sorption onto the corroding iron surface will be accompanied by an electron transfer sufficiently rapid to reduce the actinide back to the tetravalent state. This report contains the results of experimental studies of uranium reduction-depletion from water solutions in the presence of corroding iron and spectroscopic studies of the oxidation state of uranium and neptunium sorbed/precipitated onto iron under oxygen free conditions using resonant inelastic soft x-ray scattering (RIXS) spectroscopy. The RIXS measurements show that at least partial reduction of both uranyl carbonate complexes and neptunyl carbonate complexes take place on the corroding iron surface. The chemical/electrochemical measurements indicate that reduction of uranyl carbonate complexes also take place in solution in a system containing corroding iron, i.e. sorption onto the iron/iron oxide surface may not be necessary in order for reduction to take place. Reduction of uranyl hydroxyl complexes was also found to take place in solution, but at a rate that was noticeably lower than for the uranyl carbonate complexes

  10. The use of microbial and chemical analyses to characterize the variations in fouling profile of seawater reverse osmosis (SWRO) membrane

    KAUST Repository

    Manes, Carmem Lara De O; Khan, Muhammad; Molina, Veró nica Garcí a; Croue, Jean-Philippe

    2013-01-01

    and microbiological composition. The overall assessment of chemical parameters revealed that fouling layers were mainly composed by bio and organic material (proteins and lipids). Ca and Fe were found to be the most abundant elements having an increasing concentration

  11. Spectroscopy and dynamics of chemical reactions in van der Waals complexes

    International Nuclear Information System (INIS)

    Soorkia, Satchin

    2008-09-01

    Transition metal elements have d valence electrons and are characterized by a great variety of electronic configurations responsible for their specific reactivity. The elements of the second row in particular have 4d and 5s atomic orbitals of similar size and energy which can be both involved in chemical processes. We have been interested in the reactivity of a transition metal element, zirconium, combined with a simple organic functionalized molecule in a van der Waals complex formed in a supersonic molecular beam in the model reaction Zr + CH 3 F. In this context, one of the chemicals reactions that we are interested in leads to the formation of ZrF. The electronic spectroscopy of ZrF in the spectral domain 400 - 470 nm is extremely rich and surprising for a diatomic molecule. With this study, we have been able to identify the ground state of ZrF (X 2 Δ) by simulating the observed rotational structures and obtain essential information on the electronic structure. These experimental results are in agreement with ab initio calculations. The excited states of the complex Zr...F-CH 3 have been studied with a depopulation method. The spectral domain 615 - 700 nm is particularly interesting because it reveals a group of diffuse bands red-shifted and broadened with respect to the transition a 3 F → z 3 F in the metal. This transition is forbidden from the ground state a 3 F 2 of zirconium but allowed from the a 3 F 4 state. Complexation of the metal atom with a CH 3 F molecule allows coupling of these two states to occur which ensures the optical transition from the ground state of the complex. (author)

  12. Governing Influence of Thermodynamic and Chemical Equilibria on the Interfacial Properties in Complex Fluids.

    Science.gov (United States)

    Harikrishnan, A R; Dhar, Purbarun; Gedupudi, Sateesh; Das, Sarit K

    2018-04-12

    We propose a comprehensive analysis and a quasi-analytical mathematical formalism to predict the surface tension and contact angles of complex surfactant-infused nanocolloids. The model rests on the foundations of the interaction potentials for the interfacial adsorption-desorption dynamics in complex multicomponent colloids. Surfactant-infused nanoparticle-laden interface problems are difficult to deal with because of the many-body interactions and interfaces involved at the meso-nanoscales. The model is based on the governing role of thermodynamic and chemical equilibrium parameters in modulating the interfacial energies. The influence of parameters such as the presence of surfactants, nanoparticles, and surfactant-capped nanoparticles on interfacial dynamics is revealed by the analysis. Solely based on the knowledge of interfacial properties of independent surfactant solutions and nanocolloids, the same can be deduced for complex surfactant-based nanocolloids through the proposed approach. The model accurately predicts the equilibrium surface tension and contact angle of complex nanocolloids available in the existing literature and present experimental findings.

  13. Trinuclear ruthenium dioxolene complexes based on the bridging ligand hexahydroxytriphenylene: electrochemistry, spectroscopy, and near-infrared electrochromic behaviour associated with a reversible seven-membered redox chain.

    Science.gov (United States)

    Grange, Christopher S; Meijer, Anthony J H M; Ward, Michael D

    2010-01-07

    The trinuclear complexes [{(R2bipy)2Ru}3(mu3-HHTP)](PF6)3 [1(PF6)3, R = H; 2(PF6)3, R = 4-tBu] contain three {Ru(R2bipy)2}2+ fragments connected to the triangular tris-chelating ligand hexahydroxytriphenylene (H6HHTP). This bridging ligand contains three dioxolene-type binding sites, each of which can reversibly convert between dianionic catecholate (cat), monoanionic semiquinone (sq) or neutral quinone (q) redox states. The bridging ligand as a whole can therefore exist in seven different redox states from fully reduced [cat,cat,cat]6- through to fully oxidised, neutral [q,q,q]. Cyclic voltammetry of 1(PF6)3 in MeCN reveals six redox processes of which the three at more positive potentials (the sq/q couples) are reversible but the three at more negative potentials (the sq/cat couples) are irreversible with distorted wave shapes due to the insolubility of the reduced forms of the complex. In contrast, the more soluble complex 2(PF6)3 displays six reversible one-electron redox processes making all components of a seven-membered redox chain accessible. UV/Vis/NIR spectro-electrochemical studies reveal rich spectroscopic behaviour, with--in particular--very intense transitions in the near-IR region in many of the oxidation states associated with Ru(II)-->(dioxolene) MLCT and bridging ligand centred pi-pi* transitions. TDDFT calculations were used to analyse the electronic spectra in all seven oxidation states; the calculated spectra generally show very good agreement with experiment, which has allowed a fairly complete assignment of the low-energy transitions. The strong electrochromism of the complexes in the near-IR region has formed the basis of an optical window in which a thin film of 1(PF6)3 or 2(PF6)3 on a conductive glass surface can be reversibly and rapidly switched between redox states that alternate between strongly absorbing or near-transparent at 1100 nm, with--for 2(PF6)3--the switching being stable and reversible in water over thousands of cycles.

  14. Chemical Frustration. A Design Principle for the Discovery of New Complex Alloy and Intermetallic Phases, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Fredrickson, Daniel C [Univ. of Wisconsin, Madison, WI (United States)

    2015-06-23

    Final technical report for "Chemical Frustration: A Design Principle for the Discovery of New Complex Alloy and Intermetallic Phases" funded by the Office of Science through the Materials Chemistry Program of the Office of Basic Energy Sciences.

  15. Synthesis, vibrational and quantum chemical investigations of hydrogen bonded complex betaine dihydrogen selenite

    Science.gov (United States)

    Arjunan, V.; Marchewka, Mariusz K.; Kalaivani, M.

    2012-10-01

    The molecular complex of betaine with selenious acid namely, betaine dihydrogen selenite (C5H13NO5Se, BDHSe) was synthesised by the reaction of betaine and SeO2 in a 1:1:1 solution of isopropanol, methanol and water. Crystals were grown from this solution by cooling to 253 K for few days. The complex was formed without accompanying proton transfer from selenious acid molecule to betaine. The complete vibrational assignments and analysis of BDHSe have been performed by FTIR, FT-Raman and far-infrared spectral studies. More support on the experimental findings was added from the quantum chemical studies performed with DFT (B3LYP) method using 6-311++G∗∗, 6-31G∗∗, cc-pVDZ and 3-21G basis sets. The structural parameters, energies, thermodynamic parameters and the NBO charges of BDHSe were determined by the DFT method. The 1H and 13C isotropic chemical shifts (δ ppm) of BDHSe with respect to TMS were also calculated using the gauge independent atomic orbital (GIAO) method and compared with the experimental data. SHG experiment was carried out using Kurtz-Perry powder technique. The efficiency of second harmonic generation for BDHSe was estimated relatively to KDP: deff = 0.97 deff (KDP).

  16. The complex interaction between marine debris and toxic chemicals in the ocean.

    Science.gov (United States)

    Engler, Richard E

    2012-11-20

    Marine debris, especially plastic debris, is widely recognized as a global environmental problem. There has been substantial research on the impacts of plastic marine debris, such as entanglement and ingestion. These impacts are largely due to the physical presence of plastic debris. In recent years there has been an increasing focus on the impacts of toxic chemicals as they relate to plastic debris. Some plastic debris acts as a source of toxic chemicals: substances that were added to the plastic during manufacturing leach from plastic debris. Plastic debris also acts as a sink for toxic chemicals. Plastic sorbs persistent, bioaccumulative, and toxic substances (PBTs), such as polychlorinated biphenyls (PCBs) and dioxins, from the water or sediment. These PBTs may desorb when the plastic is ingested by any of a variety of marine species. This broad look at the current research suggests that while there is significant uncertainty and complexity in the kinetics and thermodynamics of the interaction, plastic debris appears to act as a vector transferring PBTs from the water to the food web, increasing risk throughout the marine food web, including humans. Because of the extremely long lifetime of plastic and PBTs in the ocean, prevention strategies are vital to minimizing these risks.

  17. Effects of Protein-pheromone Complexation on Correlated Chemical Shift Modulations

    International Nuclear Information System (INIS)

    Perazzolo, Chiara; Wist, Julien; Loth, Karine; Poggi, Luisa; Homans, Steve; Bodenhausen, Geoffrey

    2005-01-01

    Major urinary protein (MUP) is a pheromone-carrying protein of the lipocalin family. Previous studies by isothermal titration calorimetry (ITC) show that the affinity of MUP for the pheromone 2-methoxy-3-isobutylpyrazine (IBMP) is mainly driven by enthalpy, with a small unfavourable entropic contribution. Entropic terms can be attributed in part to changes in internal motions of the protein upon binding. Slow internal motions can lead to correlated or anti-correlated modulations of the isotropic chemical shifts of carbonyl C' and amide N nuclei. Correlated chemical shift modulations (CSM/CSM) in MUP have been determined by measuring differences of the transverse relaxation rates of zero- and double-quantum coherences ZQC{C'N} and DQC{C'N}, and by accounting for the effects of correlated fluctuations of dipole-dipole couplings (DD/DD) and chemical shift anisotropies (CSA/CSA). The latter can be predicted from tensor parameters of C' and N nuclei that have been determined in earlier work. The effects of complexation on slow time-scale protein dynamics can be determined by comparing the temperature dependence of the relaxation rates of APO-MUP (i.e., without ligand) and HOLO-MUP (i.e., with IBMP as a ligand)

  18. Effects of Protein-pheromone Complexation on Correlated Chemical Shift Modulations

    Energy Technology Data Exchange (ETDEWEB)

    Perazzolo, Chiara; Wist, Julien [Ecole Polytechnique Federale de Lausanne, Institut des Sciences et Ingenierie Chimiques (Switzerland); Loth, Karine; Poggi, Luisa [Ecole Normale Superieure, Departement de chimie, associe au CNRS (France); Homans, Steve [University of Leeds, School of Biochemistry and Microbiology (United Kingdom); Bodenhausen, Geoffrey [Ecole Polytechnique Federale de Lausanne, Institut des Sciences et Ingenierie Chimiques (Switzerland)], E-mail: Geoffrey.Bodenhausen@ens.fr

    2005-12-15

    Major urinary protein (MUP) is a pheromone-carrying protein of the lipocalin family. Previous studies by isothermal titration calorimetry (ITC) show that the affinity of MUP for the pheromone 2-methoxy-3-isobutylpyrazine (IBMP) is mainly driven by enthalpy, with a small unfavourable entropic contribution. Entropic terms can be attributed in part to changes in internal motions of the protein upon binding. Slow internal motions can lead to correlated or anti-correlated modulations of the isotropic chemical shifts of carbonyl C' and amide N nuclei. Correlated chemical shift modulations (CSM/CSM) in MUP have been determined by measuring differences of the transverse relaxation rates of zero- and double-quantum coherences ZQC{l_brace}C'N{r_brace} and DQC{l_brace}C'N{r_brace}, and by accounting for the effects of correlated fluctuations of dipole-dipole couplings (DD/DD) and chemical shift anisotropies (CSA/CSA). The latter can be predicted from tensor parameters of C' and N nuclei that have been determined in earlier work. The effects of complexation on slow time-scale protein dynamics can be determined by comparing the temperature dependence of the relaxation rates of APO-MUP (i.e., without ligand) and HOLO-MUP (i.e., with IBMP as a ligand)

  19. Chemical complexity in the winds of the oxygen-rich supergiant star VY Canis Majoris

    Science.gov (United States)

    Ziurys, L. M.; Milam, S. N.; Apponi, A. J.; Woolf, N. J.

    2007-06-01

    The interstellar medium is enriched primarily by matter ejected from old, evolved stars. The outflows from these stars create spherical envelopes, which foster gas-phase chemistry. The chemical complexity in circumstellar shells was originally thought to be dominated by the elemental carbon to oxygen ratio. Observations have suggested that envelopes with more carbon than oxygen have a significantly greater abundance of molecules than their oxygen-rich analogues. Here we report observations of molecules in the oxygen-rich shell of the red supergiant star VY Canis Majoris (VY CMa). A variety of unexpected chemical compounds have been identified, including NaCl, PN, HNC and HCO+. From the spectral line profiles, the molecules can be distinguished as arising from three distinct kinematic regions: a spherical outflow, a tightly collimated, blue-shifted expansion, and a directed, red-shifted flow. Certain species (SiO, PN and NaCl) exclusively trace the spherical flow, whereas HNC and sulphur-bearing molecules (amongst others) are selectively created in the two expansions, perhaps arising from shock waves. CO, HCN, CS and HCO+ exist in all three components. Despite the oxygen-rich environment, HCN seems to be as abundant as CO. These results suggest that oxygen-rich shells may be as chemically diverse as their carbon counterparts.

  20. The Challenges of Dysphagia Management and Rehabilitation in Two Complex Cases Post Chemical Ingestion Injury.

    Science.gov (United States)

    Rumbach, Anna F; Cremer, Rebecca; Chatwood, Astra; Fink, Sari; Haider, Sadaf; Yee, Michelle

    2016-11-01

    Dysphagia is common sequelae of chemical ingestion injury, resulting from damage to critical swallowing structures. From a speech-language pathology perspective, this study outlines the physiological deficits in 2 individuals with severe injury (1 woman, acid; 1 man, alkali) and the pattern of dysphagia rehabilitation and recovery. A retrospective chart review of clinical and instrumental assessments was conducted to examine swallow characteristics and speech-language pathology management (compensatory and rehabilitation strategies) at multiple time points. Chemical ingestion injury resulted in severe pharyngeal dysphagia for both participants, warranting speech-language pathology management. Dysphagia was characterized by poor base of tongue mobility and reduced laryngeal excursion. Decreased airway patency and protection, secondary to mucosal sloughing, widespread edema, and structural deficits necessitated tracheostomy. Recovery was complicated by physical alterations of pharyngeal and laryngeal structures (e.g., interarytenoid adhesions) and esophageal strictures. Participant 1 was discharged (Day 135) consuming a texture-modified diet; Participant 2 remained nil by mouth (Day 329). Dysphagia recovery subsequent to chemical ingestion is protracted and complex. Clinical outcomes may be improved through individualized and intensive rehabilitation by speech-language pathologists.

  1. Computer program for calculation of complex chemical equilibrium compositions and applications. Part 1: Analysis

    Science.gov (United States)

    Gordon, Sanford; Mcbride, Bonnie J.

    1994-01-01

    This report presents the latest in a number of versions of chemical equilibrium and applications programs developed at the NASA Lewis Research Center over more than 40 years. These programs have changed over the years to include additional features and improved calculation techniques and to take advantage of constantly improving computer capabilities. The minimization-of-free-energy approach to chemical equilibrium calculations has been used in all versions of the program since 1967. The two principal purposes of this report are presented in two parts. The first purpose, which is accomplished here in part 1, is to present in detail a number of topics of general interest in complex equilibrium calculations. These topics include mathematical analyses and techniques for obtaining chemical equilibrium; formulas for obtaining thermodynamic and transport mixture properties and thermodynamic derivatives; criteria for inclusion of condensed phases; calculations at a triple point; inclusion of ionized species; and various applications, such as constant-pressure or constant-volume combustion, rocket performance based on either a finite- or infinite-chamber-area model, shock wave calculations, and Chapman-Jouguet detonations. The second purpose of this report, to facilitate the use of the computer code, is accomplished in part 2, entitled 'Users Manual and Program Description'. Various aspects of the computer code are discussed, and a number of examples are given to illustrate its versatility.

  2. Quantum-chemical analysis of formation reactions of Со2+ complexes

    Directory of Open Access Journals (Sweden)

    Viktor F. Vargalyuk

    2017-11-01

    Full Text Available Based on the analysis of quantum chemical calculations results (GAMESS, density functional theory, B3LYP method as to coordination compounds of Co2+ions with H2O, NH3, OH–, F–, Cl–, Br–, I–, CN–, Ac–, Ak– generally given by [Co(H2O6–nLn]2+nx, it has been demonstrated that within the selected series of ligands, there is no correlation between the amount of energy of monosubstituted cobalt aqua complexes formation(∆Е and pK1,just like between the effective nuclear charge of the central atom (z*Со and pK1. According to the behavior of ∆Е and z*Со,we identified two groups of ligands. The first group (OH–, F–, Ac–, Ak–, CN–, NH3 demonstrates logical ∆Е decrease caused by the growth of z*Со. On the contrary, the second group (Cl–, Br–, I– demonstrates ∆Е increase caused by the growth of z*Со. This phenomenon is explained by the change in electronegativity and polarizability of donor atoms in groups and periods of the periodic table. It is established that linear correlations given by lgK = A + B·z*Со can be actualized only for complexes having ligands with similar donor atoms. Referring to the literature on stepwise complex formation of hydroxide, amine and chloride cobalt complexes in combination with z*Со calculations results, we determined A and B constants of lgK, z*Со-correlations for the atoms of oxygen (30.2, –17.7; nitrogen (125.4, –69.9 and chlorine (–6.3, 5.8. The existence of the detected correlation series enables us to lean on lgK,z*М–dependence parameters for the fixed donor atom and to determine Kn values for various complexes with complex-based ligands using calculations and z*М data. This applies to complexes having central atoms of the same nature as well as simple monodentate ligands. The mentioned approach was used to calculate the stability constants for acrylate cobalt complexes (lgK1 = 1.2 и lgК2 = 4.3, which are not covered in literature.

  3. The composition-explicit distillation curve technique: Relating chemical analysis and physical properties of complex fluids.

    Science.gov (United States)

    Bruno, Thomas J; Ott, Lisa S; Lovestead, Tara M; Huber, Marcia L

    2010-04-16

    The analysis of complex fluids such as crude oils, fuels, vegetable oils and mixed waste streams poses significant challenges arising primarily from the multiplicity of components, the different properties of the components (polarity, polarizability, etc.) and matrix properties. We have recently introduced an analytical strategy that simplifies many of these analyses, and provides the added potential of linking compositional information with physical property information. This aspect can be used to facilitate equation of state development for the complex fluids. In addition to chemical characterization, the approach provides the ability to calculate thermodynamic properties for such complex heterogeneous streams. The technique is based on the advanced distillation curve (ADC) metrology, which separates a complex fluid by distillation into fractions that are sampled, and for which thermodynamically consistent temperatures are measured at atmospheric pressure. The collected sample fractions can be analyzed by any method that is appropriate. The analytical methods we have applied include gas chromatography (with flame ionization, mass spectrometric and sulfur chemiluminescence detection), thin layer chromatography, FTIR, corrosivity analysis, neutron activation analysis and cold neutron prompt gamma activation analysis. By far, the most widely used analytical technique we have used with the ADC is gas chromatography. This has enabled us to study finished fuels (gasoline, diesel fuels, aviation fuels, rocket propellants), crude oils (including a crude oil made from swine manure) and waste oils streams (used automotive and transformer oils). In this special issue of the Journal of Chromatography, specifically dedicated to extraction technologies, we describe the essential features of the advanced distillation curve metrology as an analytical strategy for complex fluids. Published by Elsevier B.V.

  4. Atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry for complex thiophenic mixture analysis

    KAUST Repository

    Hourani, Nadim

    2013-10-01

    Rationale Polycyclic aromatic sulfur heterocycles (PASHs) are detrimental species for refining processes in petroleum industry. Current mass spectrometric Methods that determine their composition are often preceded by derivatization and dopant addition approaches. Different ionization Methods have different impact on the molecular assignment of complex PASHs. The analysis of such species under atmospheric pressure chemical ionization (APCI) is still considered limited due to uncontrolled ion generation with low- and high-mass PASHs. Methods The ionization behavior of a model mixture of five selected PASH standards was investigated using an APCI source with nitrogen as the reagent gas. A complex thiophenic fraction was separated from a vacuum gas oil (VGO) and injected using the same method. The samples were analyzed using Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). RESULTS PASH model analytes were successfully ionized and mainly [M + H]+ ions were produced. The same ionization pattern was observed for the real thiophenic sample. It was found that S1 class species were the major sulfur-containing species found in the VGO sample. These species indicated the presence of alkylated benzothiophenic (BT), dibenzothiophenic (DBT) and benzonaphthothiophenic (BNT) series that were detected by APCI-FTICR MS. CONCLUSIONS This study provides an established APCI-FTICR MS method for the analysis of complex PASHs. PASHs were detected without using any derivatization and without fragmentation. The method can be used for the analysis of S-containing crude oil samples. © 2013 John Wiley & Sons, Ltd.

  5. Complexing Agents and pH Influence on Chemical Durability of Type I Molded Glass Containers.

    Science.gov (United States)

    Biavati, Alberto; Poncini, Michele; Ferrarini, Arianna; Favaro, Nicola; Scarpa, Martina; Vallotto, Marta

    2017-01-01

    Among the factors that affect the glass surface chemical durability, pH and complexing agents present in aqueous solution have the main role. Glass surface attack can be also related to the delamination issue causing glass particles' appearance in the pharmaceutical preparation. A few methods to check for glass containers delamination propensity and some control guidelines have been proposed. The present study emphasizes the possible synergy between a few complexing agents with pH on borosilicate glass chemical durability.Hydrolytic attack was performed in small-volume 23 mL type I glass containers autoclaved according to the European Pharmacopoeia or United States Pharmacopeia for 1 h at 121 °C, in order to enhance the chemical attack due to time, temperature, and the unfavorable surface/volume ratio. Solutions of 0.048 M or 0.024 M (M/L) of the acids citric, glutaric, acetic, EDTA (ethylenediaminetetraacetic acid), together with sodium phosphate with water for comparison, were used for the trials. The pH was adjusted ±0.05 units at fixed values 5.5, 6.6, 7, 7.4, 8, and 9 by LiOH diluted solution.Because silicon is the main glass network former, silicon release into the attack solutions was chosen as the main index of the glass surface attack and analysed by inductively coupled plasma atomic emission spectrophotometry. The work was completed by the analysis of the silicon release in the worst attack conditions of molded glass, soda lime type II glass, and tubing borosilicate glass vials to compare different glass compositions and forming technologies. Surface analysis by scanning electron microscopy was finally performed to check for the surface status after the worst chemical attack condition by citric acid. LAY ABSTRACT: Glass, like every packaging material, can have some usage limits, mainly in basic pH solutions. The issue of glass surface degradation particles that appear in vials (delamination) has forced a number of drug product recalls in recent years

  6. Transition metal redox switches for reversible "on/off" and "slow/fast" single-molecule magnet behaviour in dysprosium and erbium bis-diamidoferrocene complexes.

    Science.gov (United States)

    Dickie, Courtney M; Laughlin, Alexander L; Wofford, Joshua D; Bhuvanesh, Nattamai S; Nippe, Michael

    2017-12-01

    Single-molecule magnets (SMMs) are considered viable candidates for next-generation data storage and quantum computing. Systems featuring switchability of their magnetization dynamics are particularly interesting with respect to accessing more complex logic gates and device architectures. Here we show that transition metal based redox events can be exploited to enable reversible switchability of slow magnetic relaxation of magnetically anisotropic lanthanide ions. Specifically, we report anionic homoleptic bis-diamidoferrocene complexes of Dy 3+ (oblate) and Er 3+ (prolate) which can be reversibly oxidized by one electron to yield their respective charge neutral redox partners (Dy: [1] - , 1 ; Er: [2] - , 2 ). Importantly, compounds 1 and 2 are thermally stable which allowed for detailed studies of their magnetization dynamics. We show that the Dy 3+ [1] - / 1 system can function as an "on"/"off" or a "slow"/"fast" redox switchable SMM system in the absence or presence of applied dc fields, respectively. The Er 3+ based [2] - / 2 system features "on"/"off" switchability of SMM properties in the presence of applied fields. Results from electrochemical investigations, UV-vis-NIR spectroscopy, and 57 Fe Mössbauer spectroscopy indicate the presence of significant electronic communication between the mixed-valent Fe ions in 1 and 2 in both solution and solid state. This comparative evaluation of redox-switchable magnetization dynamics in low coordinate lanthanide complexes may be used as a potential blueprint toward the development of future switchable magnetic materials.

  7. Quantum chemical studies on electronic structure and photodynamics of ruthenium complexes

    International Nuclear Information System (INIS)

    Freitag, L.

    2015-01-01

    Ruthenium complexes have found their way into many applications in the last decades. Among those, ruthenium polypyridyl compounds have been employed as light harvesting devices and photosensitisers in artificial photosynthesis and molecular photocatalysis. Ruthenium nitrosyl complexes are rapidly emerging as NO delivery agents to biological tissues with promising applications in anticancer photodynamic therapy, thanks to their ability to photorelease nitric oxide (NO). This thesis encompasses computational studies on reactivity, electronic structure, excited states and photodynamics of several ruthenium nitrosyl and polypyridyl complexes. The first part of the thesis deals with ruthenium nitrosyls. The cis-trans isomerisation mechanism of RuHIndNO, a ruthenium nitrosyl derivate of the prominent anti-cancer drug candidate KP1019, is investigated with density functional theory calculations. Next, the electronic structure of the ground and the first excited triplet state of RuHIndNO is studied with multiconfigurational methods including the density-matrix renormalisation group (DMRG). The obtained multiconfigurational wavefunctions and DMRG-based orbital entanglement analysis provides theoretical insight into the non-innocence of the NO ligand in nitrosyl complexes by describing the electron correlation in the Ru--NO bond and assigning oxidation states to the metal and the NO ligand. Another study is performed on excited states of ruthenium nitrosyl complexes with quantum chemical calculations and surface-hopping dynamics to obtain insights into the photodissociation mechanism of NO. The second part of this thesis is devoted to the excited states and photophysics of ruthenium polypyridyl complexes. Accurate excitation energies of tris(2,2-bipyridine)ruthenium (II), the prototype ruthenium polypyridyl are obtained with multiconfigurational calculations assisted by an orbital entanglement analysis. Subsequently, the effect of the ligand substitution on the photophysics

  8. Criterion for selection of quasi-equilibrium and quasi-frozen flows of chemically reacting mixture N2O4 reversible 2NO2reversible 2NO+O2 with heat isobaric supply (removal)

    International Nuclear Information System (INIS)

    Kostik, G.Eh.; Shiryaeva, N.M.

    1979-01-01

    Is suggested the criterion of quasi-equilibrium and quasi-frozen flows with isobaric heat supply (removal), including the basic external factors, which affect on the kinetics of chemical process. This criterion is the complex [g/Fq], where g is the coolant rate, F is the channel cross-section, q is the heat flow. Estimated formulae for quasi-equilibrium [g/Fq]sub(e) and quasi-frozen [g/Fq]sub(f) flows are obtained. The states of deviation from equilibrium and frozen conditions in linear region are considered, are listed graphical dependences lg[g/Fq]sub(e), lg[g/Fq]sub(el), lg[g/Fq]sub(f), lg[g/Eq]sub(fl), as functions of equilibrium parameter Tsub(e), pressure and frozen coordinate of epsilonsub(2f) reaction. This graphs give the possibility to estimate rapidly and obviously the flow character of chemically reacting coolant

  9. Quantum-chemical ab initio and B3LYP study of donor-acceptor complexes of gallium halides with pyridine

    International Nuclear Information System (INIS)

    Timoshkin, A.Yu.; Suvorov, A.V.; Shefer, G.F.

    1999-01-01

    By the ab initio and density functional methods the structural characteristics and vibrational spectra of gallium iodide donor-acceptor complexes with pyridine have been calculated. The standard thermodynamic characteristics of GaI 3 Py complex dissociation in gaseous phase have been calculated, as well. Short I-H intramolecular distances suggest that hydrogen iodide elimination with Ga-N chemical bond retention is the first stage of the complex pyrolysis [ru

  10. Chemical exchange in novel spirobicyclic zwitterionic Janovsky complexes using dynamic 1H NMR spectroscopy.

    Science.gov (United States)

    Culf, A S; Cuperlović-Culf, M; Ouellette, R J

    2009-02-01

    Highly coloured Janovsky complexes have been known for over 120 years, being used in many colourimetric analytical procedures. In this present study, two novel and stable nitrocyclohexadienyl spirobicyclic, zwitterionic Janovsky anionic hydantoin sigma-complexes, rac-1,3-diisopropyl-6-nitro-2,4-dioxo-1,3-diazaspiro[4.5]deca-6,9-dien-8-ylideneazinate, ammonium internal salt (1) and 1,3-diisopropyl-2,4-dioxo-1,3-diazaspiro[4.5]deca-6,9-dien-8-ylideneazinate, ammonium internal salt (2) have been prepared and characterised by NMR, electrospray ionization mass spectrometry (ESI-MS) and UV/visible methods. For the p-mononitro-substituted complex (2), we discovered chemical exchange behaviour using 1D saturation transfer and 2D exchange spectroscopy (EXSY) (1)H NMR techniques. The coalescence temperature was determined to be 62 degrees C in d(3)-acetonitrile. Analysis of these data provided a Gibbs free energy of activation, DeltaG double dagger, of + 67 kJ mole(-1), a rate constant, k, coalescence of 220 Hz and an equilibrium constant, K(eqm), of 0.98 as estimates of the exchange process in this solvent. Of the two mechanisms proposed for this fluxional behaviour, ring opening to a substituted benzene or proton exchange, a further theoretical modelling study of 1D (1)H NMR spectra was able to confirm that simple proton exchange between the two nitrogen sites of the hydantoin ring provided an accurate simulation of the observed experimental evidence. Interestingly, the o,p-dinitro-substituted complex (1) did not show any chemical exchange behaviour up to 150 degrees C in d(3)-acetonitrile (to 75 degrees C) and d(6)-dimethyl sulfoxide (DMSO). Molecular modelling at the MM2 level suggests that steric collisions of an N-acyl isopropyl substituent of the hydantoin ring with the ortho-nitro group of the spirofused cyclohexadienyl ring prevents the proposed proton exchange mechanism occurring in this case. 2008 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.

  11. Diffusion-weighted imaging of the liver at 3 T using section-selection gradient reversal: emphasis on chemical shift artefacts and lesion conspicuity

    International Nuclear Information System (INIS)

    Lee, J.S.; Kim, Y.K.; Jeong, W.K.; Choi, D.; Lee, W.J.

    2015-01-01

    Aim: To assess the value of section-selection gradient reversal (SSGR) in liver diffusion-weighted imaging (DWI) by comparing it to conventional DWI with an emphasis on chemical shift artefacts and lesion conspicuity. Materials and methods: Forty-eight patients (29 men and 19 women; age range 33–80 years) with 48 liver lesions underwent two DWI examinations using spectral presaturation with inversion recovery fat suppression with and without SSGR at 3 T. Two reviewers evaluated each DWI (b = 100 and b = 800 image) with respect to chemical shift artefacts and liver lesion conspicuity using five-point scales and performed pairwise comparisons between the two DWIs. The signal-to-noise ratio (SNR) of the liver and the lesion and the lesion–liver contrast-to-noise ratio (CNR) were also calculated. Results: SSGR-DWI was significantly better than conventional DWI with respect to chemical shift artefacts and lesion conspicuity in both separate reviews and pairwise comparisons (p < 0.05). There were significant differences in the SNR of the liver (b = 100 and b = 800 images) and lesion (b = 800) between SSGR-DWI and conventional DWI (p < 0.05). Conclusion: Applying the SSGR method to DWI using SPIR fat suppression at 3 T could significantly reduce chemical shift artefacts without incurring additional acquisition time or SNR penalties, which leads to increased conspicuity of focal liver lesions. - Highlights: • Chemical shift artefact in liver DWI is markedly decreased by applying SSGR. • Liver lesion conspicuity is improved by applying SSGR to DWI. • In SNR of the liver, SSGR-DWI is better than conventional DWI

  12. Distribution of radium and chemical toxins in the environment of a uranium complex

    International Nuclear Information System (INIS)

    Markose, P.M.; Eapen, K.P.; Venkataraman, S.; Kamath, P.R.

    1978-01-01

    The discharge of waste effluents from mining and milling of uranium ore brings into the aquatic environment radioactive pollutants and chemical toxins. The radioactive element of primary concern is radium and the nonactive pollutants are manganese, chlorides, sulphates and water hardness. In the Uranium Complex, Bihar (India), the low grade ore is mined and processed for recovery of uranium. The waste slurries from the process are neutralised and discharged into the tailings pond(TP) where the solids settle and the effluents flow out into a natural stream, Jurianala. The TP effluent mixes with mine water and floor washings from the mill in the canal on its down stream course to the river, R. Subarnarekha. This study was conducted to assess the total pollution from the liquid discharges in the environment and the impact of discharge on water quality. The results of the study of movement of pollutants in the biosphere and laboratory investigations on containment are presented. (author)

  13. Chemical and morphological gradient scaffolds to mimic hierarchically complex tissues: From theoretical modeling to their fabrication.

    Science.gov (United States)

    Marrella, Alessandra; Aiello, Maurizio; Quarto, Rodolfo; Scaglione, Silvia

    2016-10-01

    Porous multiphase scaffolds have been proposed in different tissue engineering applications because of their potential to artificially recreate the heterogeneous structure of hierarchically complex tissues. Recently, graded scaffolds have been also realized, offering a continuum at the interface among different phases for an enhanced structural stability of the scaffold. However, their internal architecture is often obtained empirically and the architectural parameters rarely predetermined. The aim of this work is to offer a theoretical model as tool for the design and fabrication of functional and structural complex graded scaffolds with predicted morphological and chemical features, to overcome the time-consuming trial and error experimental method. This developed mathematical model uses laws of motions, Stokes equations, and viscosity laws to describe the dependence between centrifugation speed and fiber/particles sedimentation velocity over time, which finally affects the fiber packing, and thus the total porosity of the 3D scaffolds. The efficacy of the theoretical model was tested by realizing engineered graded grafts for osteochondral tissue engineering applications. The procedure, based on combined centrifugation and freeze-drying technique, was applied on both polycaprolactone (PCL) and collagen-type-I (COL) to test the versatility of the entire process. A functional gradient was combined to the morphological one by adding hydroxyapatite (HA) powders, to mimic the bone mineral phase. Results show that 3D bioactive morphologically and chemically graded grafts can be properly designed and realized in agreement with the theoretical model. Biotechnol. Bioeng. 2016;113: 2286-2297. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  14. Physico-chemical properties of modified inter-polymer complexes and composites

    International Nuclear Information System (INIS)

    Khafizov, M.M.

    2004-01-01

    Full text: Inter-polymer complexes (IC) are rather perspective and can occupy the important place in technology of materials, as find out a number of the most valuable properties. In essence, they are new polymeric materials with a complex of new qualities and operational characteristics. In the present work the influence of a nature and structure of cooperating components both on structure, and on properties of received final products is investigated. It is shown new opportunities of use of the IC for reception composite materials formed IC on the physical properties, rather close to amorphous compounds. The opportunity of reception polymeric composite materials with the given properties and structure is shown; the purposeful regulation of process of hardening inter-polymeric composite materials with disperse fillers of a various nature and contents is established. The properties of such composite materials are determined by amount of entered components, both their distribution and chemical nature of a filler, that allows to increase stability properties in 2.5-3 times. By using phenomenological analysis of the contact phenomena the differential equations are made which are used for the analysis of VAC sandwich-structures metal-IC-metal. In a range of voltage V=0 -1 -10 2 V the experimental VAC are described by dependences close to Ohmic J∼V n , n=1. It is shown that the presence of breaks σ=f(T) at temperature ∼ 300 K specifies on ionic character of conductivity of samples. The chemical resistance of inter-polymeric composites in relation to water, to a solution of NaCl and 'to aggressive environment' is comprehensively characterized. The optimum degree of filling of the fillers Cv=2-3 is determined at a specific surface of fillers 0.2-0.3 m 2 /g

  15. Theoretical study of the electronic structure of f-element complexes by quantum chemical methods

    International Nuclear Information System (INIS)

    Vetere, V.

    2002-09-01

    This thesis is related to comparative studies of the chemical properties of molecular complexes containing lanthanide or actinide trivalent cations, in the context of the nuclear waste disposal. More precisely, our aim was a quantum chemical analysis of the metal-ligand bonding in such species. Various theoretical approaches were compared, for the inclusion of correlation (density functional theory, multiconfigurational methods) and of relativistic effects (relativistic scalar and 2-component Hamiltonians, relativistic pseudopotentials). The performance of these methods were checked by comparing computed structural properties to published experimental data, on small model systems: lanthanide and actinide tri-halides and on X 3 M-L species (X=F, Cl; M=La, Nd, U; L = NH 3 , acetonitrile, CO). We have thus shown the good performance of density functionals combined with a quasi-relativistic method, as well as of gradient-corrected functionals associated with relativistic pseudopotentials. In contrast, functionals including some part of exact exchange are less reliable to reproduce experimental trends, and we have given a possible explanation for this result . Then, a detailed analysis of the bonding has allowed us to interpret the discrepancies observed in the structural properties of uranium and lanthanides complexes, based on a covalent contribution to the bonding, in the case of uranium(III), which does not exist in the lanthanide(III) homologues. Finally, we have examined more sizeable systems, closer to experimental species, to analyse the influence of the coordination number, of the counter-ions and of the oxidation state of uranium, on the metal-ligand bonding. (author)

  16. Percolation via Combined Electrostatic and Chemical Doping in Complex Oxide Films

    Science.gov (United States)

    Orth, Peter P.; Fernandes, Rafael M.; Walter, Jeff; Leighton, C.; Shklovskii, B. I.

    2017-03-01

    Stimulated by experimental advances in electrolyte gating methods, we investigate theoretically percolation in thin films of inhomogeneous complex oxides, such as La1 -xSrxCoO3 (LSCO), induced by a combination of bulk chemical and surface electrostatic doping. Using numerical and analytical methods, we identify two mechanisms that describe how bulk dopants reduce the amount of electrostatic surface charge required to reach percolation: (i) bulk-assisted surface percolation and (ii) surface-assisted bulk percolation. We show that the critical surface charge strongly depends on the film thickness when the film is close to the chemical percolation threshold. In particular, thin films can be driven across the percolation transition by modest surface charge densities. If percolation is associated with the onset of ferromagnetism, as in LSCO, we further demonstrate that the presence of critical magnetic clusters extending from the film surface into the bulk results in considerable enhancement of the saturation magnetization, with pronounced experimental consequences. These results should significantly guide experimental work seeking to verify gate-induced percolation transitions in such materials.

  17. Hyperplane distance neighbor clustering based on local discriminant analysis for complex chemical processes monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chunhong; Xiao, Shaoqing; Gu, Xiaofeng [Jiangnan University, Wuxi (China)

    2014-11-15

    The collected training data often include both normal and faulty samples for complex chemical processes. However, some monitoring methods, such as partial least squares (PLS), principal component analysis (PCA), independent component analysis (ICA) and Fisher discriminant analysis (FDA), require fault-free data to build the normal operation model. These techniques are applicable after the preliminary step of data clustering is applied. We here propose a novel hyperplane distance neighbor clustering (HDNC) based on the local discriminant analysis (LDA) for chemical process monitoring. First, faulty samples are separated from normal ones using the HDNC method. Then, the optimal subspace for fault detection and classification can be obtained using the LDA approach. The proposed method takes the multimodality within the faulty data into account, and thus improves the capability of process monitoring significantly. The HDNC-LDA monitoring approach is applied to two simulation processes and then compared with the conventional FDA based on the K-nearest neighbor (KNN-FDA) method. The results obtained in two different scenarios demonstrate the superiority of the HDNC-LDA approach in terms of fault detection and classification accuracy.

  18. Extractive Atmospheric Pressure Photoionization (EAPPI) Mass Spectrometry: Rapid Analysis of Chemicals in Complex Matrices.

    Science.gov (United States)

    Liu, Chengyuan; Yang, Jiuzhong; Wang, Jian; Hu, Yonghua; Zhao, Wan; Zhou, Zhongyue; Qi, Fei; Pan, Yang

    2016-10-01

    Extractive atmospheric pressure photoionization (EAPPI) mass spectrometry was designed for rapid qualitative and quantitative analysis of chemicals in complex matrices. In this method, an ultrasonic nebulization system was applied to sample extraction, nebulization, and vaporization. Mixed with a gaseous dopant, vaporized analytes were ionized through ambient photon-induced ion-molecule reactions, and were mass-analyzed by a high resolution time-of-flight mass spectrometer (TOF-MS). After careful optimization and testing with pure sample solution, EAPPI was successfully applied to the fast screening of capsules, soil, natural products, and viscous compounds. Analysis was completed within a few seconds without the need for preseparation. Moreover, the quantification capability of EAPPI for matrices was evaluated by analyzing six polycyclic aromatic hydrocarbons (PAHs) in soil. The correlation coefficients (R (2) ) for standard curves of all six PAHs were above 0.99, and the detection limits were in the range of 0.16-0.34 ng/mg. In addition, EAPPI could also be used to monitor organic chemical reactions in real time. Graphical Abstract ᅟ.

  19. Complexity of chemical graphs in terms of size, branching, and cyclicity.

    Science.gov (United States)

    Balaban, A T; Mills, D; Kodali, V; Basak, S C

    2006-08-01

    Chemical graph complexity depends on many factors, but the main ones are size, branching, and cyclicity. Some molecular descriptors embrace together all these three parameters, which cannot then be disentangled. The topological index J (and its refinements that include accounting for bond multiplicity and the presence of heteroatoms) was designed to compensate in a significant measure for graph size and cyclicity, and therefore it contains information mainly on branching. In order to separate these factors, two new indices (F and G) related with J are proposed, which allow to group together graphs with the same size into families of constitutional formulas differing in their branching and cyclicity. A comparison with other topological indices revealed that a few other topological indices vary similarly with index G, notably DN2S4 among the triplet indices, and TOTOP among the indices contained in the Molconn-Z program. This comparison involved all possible chemical graphs (i.e. connected planar graphs with vertex degrees not higher than four) with four through six vertices, and all possible alkanes with four through nine carbon atoms.

  20. Chemical Control for Host-Parasitoid Model within the Parasitism Season and Its Complex Dynamics

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2016-01-01

    Full Text Available In the present paper, we develop a host-parasitoid model with Holling type II functional response function and chemical control, which can be applied at any time of each parasitism season or pest generation, and focus on addressing the importance of the timing of application pesticide during the parasitism season or pest generation in successful pest control. Firstly, the existence and stability of both the host and parasitoid populations extinction equilibrium and parasitoid-free equilibrium have been investigated. Secondly, the effects of key parameters on the threshold conditions have been discussed in more detail, which shows the importance of pesticide application times on the pest control. Thirdly, the complex dynamics including multiple attractors coexistence, chaotic behavior, and initial sensitivity have been studied by using numerical bifurcation analyses. Finally, the uncertainty and sensitivity of all the parameters on the solutions of both the host and parasitoid populations are investigated, which can help us to determine the key parameters in designing the pest control strategy. The present research can help us to further understand the importance of timings of pesticide application in the pest control and to improve the classical chemical control and to make management decisions.

  1. Hyperplane distance neighbor clustering based on local discriminant analysis for complex chemical processes monitoring

    International Nuclear Information System (INIS)

    Lu, Chunhong; Xiao, Shaoqing; Gu, Xiaofeng

    2014-01-01

    The collected training data often include both normal and faulty samples for complex chemical processes. However, some monitoring methods, such as partial least squares (PLS), principal component analysis (PCA), independent component analysis (ICA) and Fisher discriminant analysis (FDA), require fault-free data to build the normal operation model. These techniques are applicable after the preliminary step of data clustering is applied. We here propose a novel hyperplane distance neighbor clustering (HDNC) based on the local discriminant analysis (LDA) for chemical process monitoring. First, faulty samples are separated from normal ones using the HDNC method. Then, the optimal subspace for fault detection and classification can be obtained using the LDA approach. The proposed method takes the multimodality within the faulty data into account, and thus improves the capability of process monitoring significantly. The HDNC-LDA monitoring approach is applied to two simulation processes and then compared with the conventional FDA based on the K-nearest neighbor (KNN-FDA) method. The results obtained in two different scenarios demonstrate the superiority of the HDNC-LDA approach in terms of fault detection and classification accuracy

  2. Reversible chemical restraint of free-range cattle with a concentrated combination of tiletamine–zolazepam, ketamine, and detomidine

    Science.gov (United States)

    Re, Michela; Blanco-Murcia, Francisco J.; San Miguel, José Maria; Gómez de Segura, Ignacio A.

    2013-01-01

    The aim of this study was to determine the efficacy of a concentrated combination of tiletamine–zolazepam [TZ, 0.53 mg/kg body weight (BW)], ketamine (Ket, 0.53 mg/kg BW), and detomidine (Det, 0.04 mg/kg BW) in the immobilization of free-range cattle for clinical procedures. The combination was administered intramuscularly to 53 animals. Anesthesia was reversed with the α2-adrenoceptor antagonist atipamezole. Locoregional anesthesia was provided with lidocaine when required. The TZKD combination induced suitable immobilization for minor surgical procedures or medical treatments. Anesthetic onset was rapid, taking a mean of 6.1 min [standard deviation (SD) 2.8 min]. The duration of anesthesia depended on the time of administration of the antagonist; the animals recovered in the standing position in 12.9 ± 8.9 min after the administration of atipamezole. The quality of anesthesia and analgesia were satisfactory. In conclusion, this TZKD combination can be used for both immobilization and minor surgical procedures in free-range cattle. PMID:24124271

  3. Reversible chemical restraint of free-range cattle with a concentrated combination of tiletamine-zolazepam, ketamine, and detomidine.

    Science.gov (United States)

    Re, Michela; Blanco-Murcia, Francisco J; San Miguel, José Maria; Gómez de Segura, Ignacio A

    2013-10-01

    The aim of this study was to determine the efficacy of a concentrated combination of tiletamine-zolazepam [TZ, 0.53 mg/kg body weight (BW)], ketamine (Ket, 0.53 mg/kg BW), and detomidine (Det, 0.04 mg/kg BW) in the immobilization of free-range cattle for clinical procedures. The combination was administered intramuscularly to 53 animals. Anesthesia was reversed with the α2-adrenoceptor antagonist atipamezole. Locoregional anesthesia was provided with lidocaine when required. The TZKD combination induced suitable immobilization for minor surgical procedures or medical treatments. Anesthetic onset was rapid, taking a mean of 6.1 min [standard deviation (SD) 2.8 min]. The duration of anesthesia depended on the time of administration of the antagonist; the animals recovered in the standing position in 12.9 ± 8.9 min after the administration of atipamezole. The quality of anesthesia and analgesia were satisfactory. In conclusion, this TZKD combination can be used for both immobilization and minor surgical procedures in free-range cattle.

  4. Reversal of brain metabolic abnormalities following treatment of AIDS dementia complex with 3'-azido-2',3'-dideoxythymidine (AZT, zidovudine): a PET-FDG study

    International Nuclear Information System (INIS)

    Brunetti, A.; Berg, G.; Di Chiro, G.

    1989-01-01

    Brain glucose metabolism was evaluated in four patients with acquired immunodeficiency syndrome (AIDS) dementia complex using [ 18 F]fluorodeoxyglucose (FDG) and positron emission tomography (PET) scans at the beginning of therapy with 3'-azido-2',3'-dideoxythymidine (AZT, zidovudine), and later in the course of therapy. In two patients, baseline, large focal cortical abnormalities of glucose utilization were reversed during the course of therapy. In the other two patients, the initial PET study did not reveal pronounced focal alterations, while the post-treatment scans showed markedly increased cortical glucose metabolism. The improved cortical glucose utilization was accompanied in all patients by immunologic and neurologic improvement. PET-FDG studies can detect cortical metabolic abnormalities associated with AIDS dementia complex, and may be used to monitor the metabolic improvement in response to AZT treatment

  5. Design and Synthesis of novel CuxGeOy/Cu/C nanowires by in situ chemical reduction process with highly reversible capacity for Lithium Batteries

    International Nuclear Information System (INIS)

    Wang, Linlin; Zhang, Xiaozhu; Peng, Xia; Tang, Kaibin

    2015-01-01

    The synthesis and use of ternary metal oxides/metal particles/carbon hybrids, especially 1D naowires composed of MGeO 3 /M/C hybrids for energy storage, remains very few reports. In this work, 1D Cu x GeO y /Cu/C NWs (x < 1, y < 3) were successfully prepared by a simple method involving chemical reduction process and simultaneous carbon coating. It was found that through the polydopamine(PDA)-assisted chemical reduction process performed on the CuGeO 3 NWs, the phase partially transformed to a mixture of crystalline Cu (∼70 nm) and amorphous Cu x GeO y NWs with carbon coating, but the nanowire-shaped morphology was maintained. Electrochemical measurements showed that the Cu x GeO y /Cu/C NWs exhibited a stable reversible capacity of ∼900 mA h g −1 after 100 cycles. Even at 800 mA g −1 , it also exhibited excellent high rate capacity of 350 mA h g −1 . The newly generated Cu x GeO y @Cu@CNWs exhibit enhanced cycle stability with high lithium-storage capability compared to that of the as-preparedCuGeO 3 NWs. (*) The in situ-synthesized Cu nanoparticles, amorphous state and carbon coating might play an important role in activating and enhancing the reversibility of the conversion reaction of Cu x GeO y . In addition, this effective synthetic method might provide the methodology for the development of other ternary metal oxides/metal particles/carbon hybrids materials for energy storage.

  6. Thorium and uranium redox-active ligand complexes; reversible intramolecular electron transfer in U(dpp-BIAN)2/ U(dpp-BIAN)2(THE)

    Energy Technology Data Exchange (ETDEWEB)

    Schelter, Eric John [Los Alamos National Laboratory; Wu, Ruilian [Los Alamos National Laboratory; Scott, Brian L [Los Alamos National Laboratory; Thompson, Joe D [Los Alamos National Laboratory; Batista, Enrique R [Los Alamos National Laboratory; Morris, David E [Los Alamos National Laboratory; Kiplinger, Jaqueline L [Los Alamos National Laboratory

    2008-01-01

    Actinide complexes of the redox-active ligand dpp-BIAN{sup 2-} (dpp-BIAN = bis(2,6-diisopropylphenyl)acenaphthylene), An(dpp-BIAN){sub 2}(THF){sub n} (An = Th, n = 1; An = U, n = 0, 1) have been prepared. Solid-state magnetic and single-crystal X-ray data for U(dpp-BIAN){sub 2}(THF){sub n} show when n = 0, the complex exists in an f{sup 2}-{pi}*{sup 4} configuration; whereas an intramolecular electron transfer occurs for n = 1, resulting in an f{sup 3}-{pi}*{sup 3} ground configuration. The magnetic data also indicate that interconversion between the two forms of the complex is possible, limited only by the ability of THF vapor to penetrate the solid on cooling of the sample. Spectroscopic data indicate the complex exists solely in the f{sup 2}-{pi}*{sup 4} form in solution, evidenced by the appearance of only small changes in the electronic absorption spectra of the U(dpp-BIAN){sub 2} complex on titration with THF and by measurement of the solution magnetic moment m d{sub 8}-tetrahydrofuran using Evans method. Electrochemistry of the complexes is reported, with small differences observed in wave potentials between metals and in the presence of THF. These data represent the first example of a well-defined, reversible intramolecular electron transfer in an f-element complex and the second example of oxidation state change through dative interaction with a metal ion.

  7. Adenosine 3',5'-cyclic monophosphate (cAMP)-dependent phosphoregulation of mitochondrial complex I is inhibited by nucleoside reverse transcriptase inhibitors

    International Nuclear Information System (INIS)

    Lund, Kaleb C.; Wallace, Kendall B.

    2008-01-01

    Nucleoside analog reverse transcriptase inhibitors (NRTIs) are known to directly inhibit mitochondrial complex I activity as well as various mitochondrial kinases. Recent observations that complex I activity and superoxide production are modulated through cAMP-dependent phosphorylation suggests a mechanism through which NRTIs may affect mitochondrial respiration via kinase-dependent protein phosphorylation. In the current study, we examine the potential for NRTIs to inhibit the cAMP-dependent phosphorylation of complex I and the associated NADH:CoQ oxidoreductase activities and rates of superoxide production using HepG2 cells. Phosphoprotein staining of immunocaptured complex I revealed that 3'-azido-3'-deoxythymidine (AZT; 10 and 50 μM), AZT monophosphate (150 μM), and 2',3'-dideoxycytidine (ddC; 1 μM) prevented the phosphorylation of the NDUFB11 subunit of complex I. This was associated with a decrease in complex I activity with AZT and AZT monophosphate only. In the presence of succinate, superoxide production was increased with 2',3'-dideoxyinosine (ddI; 10 μM) and ddC (1 μM). In the presence of succinate + cAMP, AZT showed an inverse dose-dependent effect on superoxide production. None of the NRTIs examined inhibit PKA activity suggesting that the observed effects are due to a direct interaction with complex I. These data demonstrate a direct effect of NRTIs on cAMP-dependent regulation of mitochondrial bioenergetics independent of DNA polymerase-γ activity; in the case of AZT, these observations may provide a mechanism for the observed long-term toxicity with this drug

  8. Reactive oxygen species are generated by the respiratory complex II - evidence for lack of contribution of the reverse electron flow in complex I

    Czech Academy of Sciences Publication Activity Database

    Moreno-Sanchez, R.; Hernandez-Esquivel, L.; Rivero-Segura, N.A.; Marin-Hernandez, A.; Neužil, Jiří; Ralph, S. J.; Rodriguez-Enriquez, S.

    2013-01-01

    Roč. 280, č. 3 (2013), s. 927-938 ISSN 1742-464X Institutional research plan: CEZ:AV0Z50520701 Keywords : anti-cancer drugs * mitochondria * respiratory complex II Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.986, year: 2013

  9. System sight at a problem of efficiency of enterprises’s operaton of the Russian chemical complex

    Directory of Open Access Journals (Sweden)

    Svyatoslav Arkadyevich Nikitin

    2011-06-01

    Full Text Available Chemical industry plays an important role in the development of the domestic economy as one of the basic facilities of Russia's economy, laying the foundation for its long-term and stable development. As a major supplier of raw materials, intermediates, and products of various materials (plastics, chemical fibers, tires, paints and varnishes, dyes, fertilizers, feed additives, pharmaceuticals, medical equipment etc. in almost all sectors of industry, agriculture, health care, human services, commerce, science, culture and education, defense industry, chemical complex has direct impact on the efficiency of their operation and development in these new directions. Therefore, the condition and development of domestic chemistry determines the level of national competitiveness, economic growth and Russia's wealth. However, like most industries in Russia today, chemical industry is going through a difficult period. The presence of a set of common economic problems (identified by technological backwardness and high depreciation, low innovation activity of domestic enterprises of the chemical complex, a lack of effectiveness of the investment process, infrastructure and resource constraints etc., as well as internal management problems causes the rapid growth of interest of uncompetitive Russian chemical products on the world market. Under these conditions, not only a radical adjustment of the internal control systems and chemical plants, but also a significant organizational and economic change is required. Thus, unless we take measures to improve the domestic chemical industry in the coming years, almost all of it grow back and may get into the situation of struggle for survival.

  10. Extracting Lane Geometry and Topology Information from Vehicle Fleet Trajectories in Complex Urban Scenarios Using a Reversible Jump Mcmc Method

    Science.gov (United States)

    Roeth, O.; Zaum, D.; Brenner, C.

    2017-05-01

    Highly automated driving (HAD) requires maps not only of high spatial precision but also of yet unprecedented actuality. Traditionally small highly specialized fleets of measurement vehicles are used to generate such maps. Nevertheless, for achieving city-wide or even nation-wide coverage, automated map update mechanisms based on very large vehicle fleet data gain importance since highly frequent measurements are only to be obtained using such an approach. Furthermore, the processing of imprecise mass data in contrast to few dedicated highly accurate measurements calls for a high degree of automation. We present a method for the generation of lane-accurate road network maps from vehicle trajectory data (GPS or better). Our approach therefore allows for exploiting today's connected vehicle fleets for the generation of HAD maps. The presented algorithm is based on elementary building blocks which guarantees useful lane models and uses a Reversible Jump Markov chain Monte Carlo method to explore the models parameters in order to reconstruct the one most likely emitting the input data. The approach is applied to a challenging urban real-world scenario of different trajectory accuracy levels and is evaluated against a LIDAR-based ground truth map.

  11. Unquenched Complex Dirac Spectra at Nonzero Chemical Potential: Two-Color QCD Lattice Data versus Matrix Model

    International Nuclear Information System (INIS)

    Akemann, Gernot; Bittner, Elmar

    2006-01-01

    We compare analytic predictions of non-Hermitian chiral random matrix theory with the complex Dirac operator eigenvalue spectrum of two-color lattice gauge theory with dynamical fermions at nonzero chemical potential. The Dirac eigenvalues come in complex conjugate pairs, making the action of this theory real and positive for our choice of two staggered flavors. This enables us to use standard Monte Carlo simulations in testing the influence of the chemical potential and quark mass on complex eigenvalues close to the origin. We find excellent agreement between the analytic predictions and our data for two different volumes over a range of chemical potentials below the chiral phase transition. In particular, we detect the effect of unquenching when going to very small quark masses

  12. Nonlinear absorbing cationic iridium(III) complexes bearing benzothiazolylfluorene motif on the bipyridine (N∧N) ligand: synthesis, photophysics and reverse saturable absorption.

    Science.gov (United States)

    Li, Yuhao; Dandu, Naveen; Liu, Rui; Hu, Lei; Kilina, Svetlana; Sun, Wenfang

    2013-07-24

    Four new heteroleptic cationic Ir(III) complexes bearing benzothiazolylfluorene motif on the bipyridine (N∧N) (1 and 2) and phenylpyridine (C∧N) (3 and 4) ligands are synthesized and characterized. The influence of the position of the substituent and the extent of π-conjugation on the photophysics of these complexes is systematically investigated by spectroscopic methods and simulated by time-dependent density functional theory (TDDFT). The complexes exhibit ligand-centered (1)π,π* transitions with admixtures of (1)ILCT (π(benzothiazolylfluorene) → π*(bpy)) and (1)MLCT (metal-to-ligand charge transfer) characters below 475 nm, and very weak (1,3)MLCT and (1,3)LLCT (ligand-to-ligand charge transfer) transitions above 475 nm. The emission of these complexes at room temperature in CH2Cl2 solutions is ascribed to be predominantly from the (3)MLCT/(3)LLCT states for 1 and from the (3)π,π* state for 2, while the emitting state of 3 and 4 are assigned to be an admixture of (3)MLCT, (3)LLCT, and (3)π,π* characters. The variations of the photophysical properties of 1-4 are attributed to different degrees of π-conjugation in the bipyridine and phenylpyridine ligands induced by different positions of the benzothiazolylfluorenyl substituents on the bipyridine ligand and different extents of π-conjugation in the phenylpyridine ligands, which alters the energy and lifetime of the lowest singlet and triplet excited states. 1-4 all possess broadband transient absorption (TA) upon nanosecond laser excitation, which extends from the visible to the NIR region. Therefore, 1-4 all exhibit strong reverse saturable absorption (RSA) at 532 nm for ns laser pulses. However, the TA of complexes 1, 2, and 3 are much stronger than that of 4. This feature, combined with the difference in ground-state absorption and triplet excited-state quantum yield, result in the difference in RSA strength, which follows this trend: 1 ≈ 2 ≈ 3 > 4. Therefore, complexes 1-3 are strong

  13. Hydride Reactivity of Ni-II-X-Ni-II Entities : Mixed-Valent Hydrido Complexes and Reversible Metal Reduction

    NARCIS (Netherlands)

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

    After the lithiation of PYR-H2 (PYR2-=[{NC(Me)C(H)C(Me)NC6H3(iPr)2}2(C5H3N)]2-), which is the precursor of an expanded beta-diketiminato ligand system with two binding pockets, its reaction with [NiBr2(dme)] led to a dinuclear nickel(II)bromide complex, [(PYR)Ni(mu-Br)NiBr] (1). The bridging bromide

  14. A Chemical Composition Survey of the Iron-complex Globular Cluster NGC 6273 (M19)

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Christian I.; Caldwell, Nelson [Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, MS-15, Cambridge, MA 02138 (United States); Rich, R. Michael [Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547 (United States); Mateo, Mario [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Bailey, John I. III [Leiden Observatory, Leiden University, P.O. Box 9513, 2300RA Leiden (Netherlands); Clarkson, William I. [Department of Natural Sciences, University of Michigan–Dearborn, 4901 Evergreen Road, Dearborn, MI 48128 (United States); Olszewski, Edward W. [Steward Observatory, The University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Walker, Matthew G., E-mail: cjohnson@cfa.harvard.edu, E-mail: ncaldwell@cfa.harvard.edu, E-mail: rmr@astro.ucla.edu, E-mail: mmateo@umich.edu, E-mail: baileyji@strw.leidenuniv.nl, E-mail: wiclarks@umich.edu, E-mail: eolszewski@as.arizona.edu, E-mail: mgwalker@andrew.cmu.edu [McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States)

    2017-02-20

    Recent observations have shown that a growing number of the most massive Galactic globular clusters contain multiple populations of stars with different [Fe/H] and neutron-capture element abundances. NGC 6273 has only recently been recognized as a member of this “iron-complex” cluster class, and we provide here a chemical and kinematic analysis of >300 red giant branch and asymptotic giant branch member stars using high-resolution spectra obtained with the Magellan –M2FS and VLT–FLAMES instruments. Multiple lines of evidence indicate that NGC 6273 possesses an intrinsic metallicity spread that ranges from about [Fe/H] = −2 to −1 dex, and may include at least three populations with different [Fe/H] values. The three populations identified here contain separate first (Na/Al-poor) and second (Na/Al-rich) generation stars, but a Mg–Al anti-correlation may only be present in stars with [Fe/H] ≳ −1.65. The strong correlation between [La/Eu] and [Fe/H] suggests that the s-process must have dominated the heavy element enrichment at higher metallicities. A small group of stars with low [ α /Fe] is identified and may have been accreted from a former surrounding field star population. The cluster’s large abundance variations are coupled with a complex, extended, and multimodal blue horizontal branch (HB). The HB morphology and chemical abundances suggest that NGC 6273 may have an origin that is similar to ω Cen and M54.

  15. Energy and environment efficiency analysis based on an improved environment DEA cross-model: Case study of complex chemical processes

    International Nuclear Information System (INIS)

    Geng, ZhiQiang; Dong, JunGen; Han, YongMing; Zhu, QunXiong

    2017-01-01

    Highlights: •An improved environment DEA cross-model method is proposed. •Energy and environment efficiency analysis framework of complex chemical processes is obtained. •This proposed method is efficient in energy-saving and emission reduction of complex chemical processes. -- Abstract: The complex chemical process is a high pollution and high energy consumption industrial process. Therefore, it is very important to analyze and evaluate the energy and environment efficiency of the complex chemical process. Data Envelopment Analysis (DEA) is used to evaluate the relative effectiveness of decision-making units (DMUs). However, the traditional DEA method usually cannot genuinely distinguish the effective and inefficient DMU due to its extreme or unreasonable weight distribution of input and output variables. Therefore, this paper proposes an energy and environment efficiency analysis method based on an improved environment DEA cross-model (DEACM) method. The inputs of the complex chemical process are divided into energy and non-energy inputs. Meanwhile, the outputs are divided into desirable and undesirable outputs. And then the energy and environment performance index (EEPI) based on the cross evaluation is used to represent the overall performance of each DMU. Moreover, the improvement direction of energy-saving and carbon emission reduction of each inefficiency DMU is quantitatively obtained based on the self-evaluation model of the improved environment DEACM. The results show that the improved environment DEACM method has a better effective discrimination than the original DEA method by analyzing the energy and environment efficiency of the ethylene production process in complex chemical processes, and it can obtain the potential of energy-saving and carbon emission reduction of ethylene plants, especially the improvement direction of inefficient DMUs to improve energy efficiency and reduce carbon emission.

  16. Intraparticulate Metal Speciation Analysis of Soft Complexing Nanoparticles. The Intrinsic Chemical Heterogeneity of Metal-Humic Acid Complexes

    DEFF Research Database (Denmark)

    Town, R. M.; van Leeuwen, Herman P.

    2016-01-01

    ion condensation potential for higher valency counterions within the intraparticulate double layer zone of the soft NP. The approach offers new insights into the intrinsic heterogeneity of the HA. complexes, as revealed by the intraparticulate speciation as a function of the true degree of inner......-sphere complexation, theta(M). The ensuing intrinsic heterogeneity parameters, Gamma, for CdHA and CuHA complexes are in very good agreement with those obtained from dynamic electrochemical stripping chronopotentiometric measurements. The overall intraparticulate metal ion speciation is found to depend on theta...

  17. Oxidation of nitrite by a trans-dioxoruthenium(VI) complex: direct evidence for reversible oxygen atom transfer.

    Science.gov (United States)

    Man, Wai-Lun; Lam, William W Y; Wong, Wai-Yeung; Lau, Tai-Chu

    2006-11-15

    Reaction of trans-[Ru(VI)(L)(O)(2)](2+) (1, L = 1,12-dimethyl-3,4:9,10-dibenzo-1,12-diaza-5,8-dioxacyclopentadecane, a tetradentate macrocyclic ligand with N(2)O(2) donor atoms) with nitrite in aqueous solution or in H(2)O/CH(3)CN produces the corresponding (nitrato)oxoruthenium(IV) species, trans-[Ru(IV)(L)(O)(ONO(2))](+) (2), which then undergoes relatively slow aquation to give trans-[Ru(IV)(L)(O)(OH(2))](2+). These processes have been monitored by both ESI/MS and UV/vis spectrophotometry. The structure of trans-[Ru(IV)(L)(O)(ONO(2))](+) (2) has been determined by X-ray crystallography. The ruthenium center adopts a distorted octahedral geometry with the oxo and the nitrato ligands trans to each other. The Ru=O distance is 1.735(3) A, the Ru-ONO(2) distance is 2.163(4) A, and the Ru-O-NO(2) angle is 138.46(35) degrees . Reaction of trans-[Ru(VI)(L)((18)O)(2)](2+) (1-(18)O(2)) with N(16)O(2)(-) in H(2)O/CH(3)CN produces the (18)O-enriched (nitrato)oxoruthenium(IV) species 2-(18)O(2). Analysis of the ESI/MS spectrum of 2-(18)O(2) suggests that scrambling of the (18)O atoms has occurred. A mechanism that involves linkage isomerization of the nitrato ligand and reversible oxygen atom transfer is proposed.

  18. Computational Cellular Dynamics Based on the Chemical Master Equation: A Challenge for Understanding Complexity.

    Science.gov (United States)

    Liang, Jie; Qian, Hong

    2010-01-01

    Modern molecular biology has always been a great source of inspiration for computational science. Half a century ago, the challenge from understanding macromolecular dynamics has led the way for computations to be part of the tool set to study molecular biology. Twenty-five years ago, the demand from genome science has inspired an entire generation of computer scientists with an interest in discrete mathematics to join the field that is now called bioinformatics. In this paper, we shall lay out a new mathematical theory for dynamics of biochemical reaction systems in a small volume (i.e., mesoscopic) in terms of a stochastic, discrete-state continuous-time formulation, called the chemical master equation (CME). Similar to the wavefunction in quantum mechanics, the dynamically changing probability landscape associated with the state space provides a fundamental characterization of the biochemical reaction system. The stochastic trajectories of the dynamics are best known through the simulations using the Gillespie algorithm. In contrast to the Metropolis algorithm, this Monte Carlo sampling technique does not follow a process with detailed balance. We shall show several examples how CMEs are used to model cellular biochemical systems. We shall also illustrate the computational challenges involved: multiscale phenomena, the interplay between stochasticity and nonlinearity, and how macroscopic determinism arises from mesoscopic dynamics. We point out recent advances in computing solutions to the CME, including exact solution of the steady state landscape and stochastic differential equations that offer alternatives to the Gilespie algorithm. We argue that the CME is an ideal system from which one can learn to understand "complex behavior" and complexity theory, and from which important biological insight can be gained.

  19. Reverse Algols

    Science.gov (United States)

    Leung, K. C.

    1989-01-01

    Reverse Algols, binary systems with a semidetached configuration in which the more massive component is in contact with the critical equipotential surface, are examined. Observational evidence for reverse Algols is presented and the parameters of seven reverse Algols are listed. The evolution of Algols and reverse Algols is discussed. It is suggested that, because reverse Algols represent the premass-reversal semidetached phase of close binary evolution, the evolutionary time scale between regular and reverse Algols is the ratio of the number of confirmed systems of these two Algol types.

  20. Tuning affinity and reversibility for O2 binding in dinuclear Co(II) complexes

    DEFF Research Database (Denmark)

    Vad, Mads Sørensen; Johansson, Frank Bartnik; Seidler-Egdal, Rune Kirk

    2013-01-01

    The O2 binding affinity of a series of dicobalt(II) complexes can be tuned between p(O2)50% = 2.3 × 10−3 and 700 × 10−3 atm at 40 °C by varying the number of H and Cl atoms in the bridging acetato ligands of [Co2(bpbp)(CH(3−n)ClnCO2)(CH3CN)2]2+, where bpbp− = 2,6-bis(N,N-bis(2-pyridylmethyl)amino...

  1. Reverse Logistics

    OpenAIRE

    Kulikova, Olga

    2016-01-01

    This thesis was focused on the analysis of the concept of reverse logistics and actual reverse processes which are implemented in mining industry and finding solutions for the optimization of reverse logistics in this sphere. The objective of this paper was the assessment of the development of reverse logistics in mining industry on the example of potash production. The theoretical part was based on reverse logistics and mining waste related literature and provided foundations for further...

  2. Affective salience can reverse the effects of stimulus-driven salience on eye movements in complex scenes

    Directory of Open Access Journals (Sweden)

    Yaqing eNiu

    2012-09-01

    Full Text Available In natural vision both stimulus features and cognitive/affective factors influence an observer's attention. However, the relationship between stimulus-driven (bottom-up and cognitive/affective (top-down factors remains controversial: Can affective salience counteract strong visual stimulus signals and shift attention allocation irrespective of bottom-up features? Is there any difference between negative and positive scenes in terms of their influence on attention deployment? Here we examined the impact of affective factors on eye movement behavior, to understand the competition between visual stimulus-driven salience and affective salience and how they affect gaze allocation in complex scene viewing. Building on our previous research, we compared predictions generated by a visual salience model with measures indexing participant-identified emotionally meaningful regions of each image. To examine how eye movement behaviour differs for negative, positive, and neutral scenes, we examined the influence of affective salience in capturing attention according to emotional valence. Taken together, our results show that affective salience can override stimulus-driven salience and overall emotional valence can determine attention allocation in complex scenes. These findings are consistent with the hypothesis that cognitive/affective factors play a dominant role in active gaze control.

  3. Rif1 controls DNA replication by directing Protein Phosphatase 1 to reverse Cdc7-mediated phosphorylation of the MCM complex.

    Science.gov (United States)

    Hiraga, Shin-Ichiro; Alvino, Gina M; Chang, Fujung; Lian, Hui-Yong; Sridhar, Akila; Kubota, Takashi; Brewer, Bonita J; Weinreich, Michael; Raghuraman, M K; Donaldson, Anne D

    2014-02-15

    Initiation of eukaryotic DNA replication requires phosphorylation of the MCM complex by Dbf4-dependent kinase (DDK), composed of Cdc7 kinase and its activator, Dbf4. We report here that budding yeast Rif1 (Rap1-interacting factor 1) controls DNA replication genome-wide and describe how Rif1 opposes DDK function by directing Protein Phosphatase 1 (PP1)-mediated dephosphorylation of the MCM complex. Deleting RIF1 partially compensates for the limited DDK activity in a cdc7-1 mutant strain by allowing increased, premature phosphorylation of Mcm4. PP1 interaction motifs within the Rif1 N-terminal domain are critical for its repressive effect on replication. We confirm that Rif1 interacts with PP1 and that PP1 prevents premature Mcm4 phosphorylation. Remarkably, our results suggest that replication repression by Rif1 is itself also DDK-regulated through phosphorylation near the PP1-interacting motifs. Based on our findings, we propose that Rif1 is a novel PP1 substrate targeting subunit that counteracts DDK-mediated phosphorylation during replication. Fission yeast and mammalian Rif1 proteins have also been implicated in regulating DNA replication. Since PP1 interaction sites are evolutionarily conserved within the Rif1 sequence, it is likely that replication control by Rif1 through PP1 is a conserved mechanism.

  4. Synthesis and characterization of lead sulphide thin films from ethanolamine (ETA) complexing agent chemical bath

    Science.gov (United States)

    Gashaw Hone, Fekadu; Dejene, F. B.

    2018-02-01

    Polycrystalline lead sulphide (PbS) thin films were grown on glass substrates by chemical bath deposition route using ethanolamine (ETA) as a complexing agent. The effects of ETA molar concentration on the structural, morphological, electrical and optical properties of lead sulphide thin films were thoroughly studied. The XRD analyses revealed that all the deposited thin films were face center cubic crystal structure and their preferred orientations were varied along the (111) and (200) planes. The XRD results further confirmed that ETA concentration had a significant effects on the strain, average crystalline size and dislocation density of the deposited thin films. The SEM studies illustrated the evolution and transformation of surface morphology as ETA molar concentration increased from 0.41 M to 1.64 M. The energy dispersive x-ray analysis was used to verify the compositional elements of the deposited thin films. Optical spectroscopy investigation established that the band gap of the PbS thin films were reduced from 0.98 eV to 0.68 eV as ETA concentration increased. The photoluminescence spectra showed a well defined peak at 428 nm and shoulder around 468 nm for all PbS thin films. The electrical resistivity of the thin films found in the order of 103 Ω cm at room temperature and decreased as the ETA molar concentration was increased.

  5. The influence of the "cage" effect on the mechanism of reversible bimolecular multistage chemical reactions proceeding from different sites in solutions.

    Science.gov (United States)

    Doktorov, Alexander B

    2016-08-28

    Manifestations of the "cage" effect at the encounters of reactants have been theoretically treated on the example of multistage reactions (including bimolecular exchange reactions as elementary stages) proceeding from different active sites in liquid solutions. It is shown that for reactions occurring near the contact of reactants, consistent consideration of quasi-stationary kinetics of such multistage reactions (possible in the framework of the encounter theory only) can be made on the basis of chemical concepts of the "cage complex," just as in the case of one-site model described in the literature. Exactly as in the one-site model, the presence of the "cage" effect gives rise to new channels of reactant transformation that cannot result from elementary event of chemical conversion for the given reaction mechanism. Besides, the multisite model demonstrates new (as compared to one-site model) features of multistage reaction course.

  6. Effect of emulsifiers on complexation and retrogradation characteristics of native and chemically modified White sorghum (Sorghum bicolor) starch

    International Nuclear Information System (INIS)

    Ali, Tahira Mohsin; Hasnain, Abid

    2013-01-01

    Highlights: ► Sorghum starches were chemically modified. ► Starch–lipid complexes were studied in the presence of emulsifiers. ► Type II complexes were also detected in native and oxidized starches on adding GMS. ► Starch–lipid complexes sharply reduced retrogradation in modified starches. - Abstract: The effect of emulsifiers on complexation and retrogradation characteristics of native and chemically modified white sorghum starches was studied. Complex forming tendency of white sorghum starch with commercially available emulsifiers GMS and DATEM improved after acetylation. Presence of emulsifiers reduced λ max (wavelength of maximum absorbance) both for native and modified sorghum starches suggesting lower availability of amylose chains to complex with iodine. In native white sorghum starch (NWSS) and oxidized white sorghum starch (OWSS), both Type I and Type II starch–lipid complexes were observed on addition of 1.0% GMS prior to gelatinization. Acetylated-oxidized white sorghum starch (AOWSS) formed weakest complexes among all the modified starches. The results revealed that antistaling characteristics of modified sorghum starches were enhanced when used in combination with emulsifiers. The most prominent decline in reassociative capability among modified starches was observed for acetylated starches.

  7. Power of magic hands: parent-driven application of habit reversal to treat complex stereotypy in a 3-year-old.

    Science.gov (United States)

    Freeman, Kurt A; Duke, Danny C

    2013-08-01

    The authors assessed the effectiveness of habit reversal training (HRT) to treat a complex motor stereotypy in a healthy 3-year-old female. This data-based case study involved training parents in HRT to deliver the parent-driven intervention to the child. The frequency of the child's behaviors was estimated daily in 30-min intervals by her parents. Outcomes supported the effectiveness of the intervention, with the estimated frequency of the stereotypy decreasing from occurring during approximately 85% of recorded intervals to less than 2% over a period of 4 weeks. Further record keeping over 19 weeks suggested treatment gains were generally maintained over time. The current case study provides preliminary evidence supporting the effectiveness of modified HRT to reduce stereotypies in young children. Further, data suggest that the intervention may be extended to younger ages by teaching parents how to facilitate treatment delivery. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  8. Advanced 3D tools used in reverse engineering and ray tracing simulation of phased array inspection of turbine components with complex geometry

    International Nuclear Information System (INIS)

    Daks, W.; Kovacshazy, C.; Mair, D.; Ciorau, P.

    2002-01-01

    This paper outlines the practical aspects of reverse engineering and the integration of multiple pieces of software (Drafting, CNC Machining, Ray Tracing, Inspection Simulation Scenario and Phased Array UT Analysis), in order to inspect turbine components comprised of complex geometry. The CNC software, Mastercam, and design software, CADKEY/FastSURF, were used to validate the phased-array automated and manual inspection of blade root, rotor steeples and disk-blade rim attachment. The integration of a 3D part in the software engine, Imagine 3D and SimScan, as well as Tomoview analysis (specimen feature) is based on CADKEY Developer Kit - IGES/SAT file format. A generic Ray Tracing simulation for multi-probe beam was integrated into Imagine 3D. Representative examples of reference blocks and mock-ups, UT simulation and phased-array data comparison are presented. (author)

  9. Putative supramolecular complexes formed by carotenoids and xanthophylls with ascorbic acid to reverse multidrug resistance in cancer cells.

    Science.gov (United States)

    Molnár, József; Serly, Julianna; Pusztai, Rozália; Vincze, Irén; Molnár, Péter; Horváth, Györgyi; Deli, József; Maoka, Takashi; Zalatnai, Attila; Tokuda, Harukuni; Nishino, Hoyoku

    2012-02-01

    The molecular basis of interaction of selected carotenoids and xanthophylls with ascorbic acid on cancer cells was studied to determine their anticancer effects. Drug accumulation was measured in a human ABCB1 gene-transfected mouse lymphoma cell line and in a human lung cancer cell line by flow cytometry; furthermore, their anticancer effects were determined in mice in vivo. Several carotenoids inhibited the multidrug resistance of cancer cells. Ascorbic acid improved the effect of certain xanthophylls, but the effect of capsanthin was not modified. Capsanthin had weak (12%) but capsorubin (85%) had a remarkable antiproliferative effect on A549 lung cancer cells. Capsorubin reduced immediate-early tumor antigen expression, while capsanthin was not effective. Capsorubin accumulates selectively in the nuclei of cancer cells. The Authors suggest a special complex formation between membrane-bound capsorubin and ascorbic acid, which can be exploited in experimental chemotherapy.

  10. Reversible Low-Light Induced Photoswitching of Crowned Spiropyran-DO3A Complexed with Gadolinium(III Ions

    Directory of Open Access Journals (Sweden)

    André Knoesen

    2012-05-01

    Full Text Available Photoswitchable spiropyran has been conjugated to the crowned ring system DO3A, which improves its solubility in dipolar and polar media and stabilizes the merocyanine isomer. Adding the lanthanide ion gadolinium(III to the macrocyclic ring system leads to a photoresponsive magnetic resonance imaging contrast agent that displays an increased spin-lattice relaxation time (T1 upon visible light stimulation. In this work, the photoresponse of this photochromic molecule to weak light illumination using blue and green light emitting diodes was investigated, simulating the emission spectra from bioluminescent enzymes. Photon emission rate of the light emitting diodes was changed, from 1.75 × 1016 photons·s−1 to 2.37 × 1012 photons·s−1. We observed a consistent visible light-induced isomerization of the merocyanine to the spiropyran form with photon fluxes as low as 2.37 × 1012 photons·s−1 resulting in a relaxivity change of the compound. This demonstrates the potential for use of the described imaging probes in low light level applications such as sensing bioluminescence enzyme activity. The isomerization behavior of gadolinium(III-ion complexed and non-complexed spiropyran-DO3A was analyzed in water and ethanol solution in response to low light illumination and compared to the emitted photon emission rate from over-expressed Gaussia princeps luciferase.

  11. The impact of sex-role reversal on the diversity of the major histocompatibility complex: insights from the seahorse (Hippocampus abdominalis).

    Science.gov (United States)

    Bahr, Angela; Wilson, Anthony B

    2011-05-10

    Both natural and sexual selection are thought to influence genetic diversity, but the study of the relative importance of these two factors on ecologically-relevant traits has traditionally focused on species with conventional sex-roles, with male-male competition and female-based mate choice. With its high variability and significance in both immune function and olfactory-mediated mate choice, the major histocompatibility complex (MHC/MH) is an ideal system in which to evaluate the relative contributions of these two selective forces to genetic diversity. Intrasexual competition and mate choice are both reversed in sex-role reversed species, and sex-related differences in the detection and use of MH-odor cues are expected to influence the intensity of sexual selection in such species. The seahorse, Hippocampus abdominalis, has an exceptionally highly developed form of male parental care, with female-female competition and male mate choice. Here, we demonstrate that the sex-role reversed seahorse has a single MH class II beta-chain gene and that the diversity of the seahorse MHIIβ locus and its pattern of variation are comparable to those detected in species with conventional sex roles. Despite the presence of only a single gene copy, intralocus MHIIβ allelic diversity in this species exceeds that observed in species with multiple copies of this locus. The MHIIβ locus of the seahorse exhibits a novel expression domain in the male brood pouch. The high variation found at the seahorse MHIIβ gene indicates that sex-role reversed species are capable of maintaining the high MHC diversity typical in most vertebrates.Whether such species have evolved the capacity to use MH-odor cues during mate choice is presently being investigated using mate choice experiments. If this possibility can be rejected, such systems would offer an exceptional opportunity to study the effects of natural selection in isolation, providing powerful comparative models for understanding the

  12. The impact of sex-role reversal on the diversity of the major histocompatibility complex: Insights from the seahorse (Hippocampus abdominalis

    Directory of Open Access Journals (Sweden)

    Wilson Anthony B

    2011-05-01

    Full Text Available Abstract Background Both natural and sexual selection are thought to influence genetic diversity, but the study of the relative importance of these two factors on ecologically-relevant traits has traditionally focused on species with conventional sex-roles, with male-male competition and female-based mate choice. With its high variability and significance in both immune function and olfactory-mediated mate choice, the major histocompatibility complex (MHC/MH is an ideal system in which to evaluate the relative contributions of these two selective forces to genetic diversity. Intrasexual competition and mate choice are both reversed in sex-role reversed species, and sex-related differences in the detection and use of MH-odor cues are expected to influence the intensity of sexual selection in such species. The seahorse, Hippocampus abdominalis, has an exceptionally highly developed form of male parental care, with female-female competition and male mate choice. Results Here, we demonstrate that the sex-role reversed seahorse has a single MH class II beta-chain gene and that the diversity of the seahorse MHIIβ locus and its pattern of variation are comparable to those detected in species with conventional sex roles. Despite the presence of only a single gene copy, intralocus MHIIβ allelic diversity in this species exceeds that observed in species with multiple copies of this locus. The MHIIβ locus of the seahorse exhibits a novel expression domain in the male brood pouch. Conclusions The high variation found at the seahorse MHIIβ gene indicates that sex-role reversed species are capable of maintaining the high MHC diversity typical in most vertebrates. Whether such species have evolved the capacity to use MH-odor cues during mate choice is presently being investigated using mate choice experiments. If this possibility can be rejected, such systems would offer an exceptional opportunity to study the effects of natural selection in isolation

  13. Application of the threshold of toxicological concern (TTC) concept to the safety assessment of chemically complex food matrices

    NARCIS (Netherlands)

    Rennen, M.A.J.; Koster, S.; Krul, C.A.M.; Houben, G.F.

    2011-01-01

    The toxicological assessment of chemically complex food matrices (CCFM) usually is very time consuming, expensive and uses many animal studies. Improvements to obtain a more efficient assessment process remain limited as long as we retain traditional approaches to toxicological risk assessment. New

  14. Complementation of biotransformations with chemical C-H oxidation: copper-catalyzed oxidation of tertiary amines in complex pharmaceuticals.

    Science.gov (United States)

    Genovino, Julien; Lütz, Stephan; Sames, Dalibor; Touré, B Barry

    2013-08-21

    The isolation, quantitation, and characterization of drug metabolites in biological fluids remain challenging. Rapid access to oxidized drugs could facilitate metabolite identification and enable early pharmacology and toxicity studies. Herein, we compared biotransformations to classical and new chemical C-H oxidation methods using oxcarbazepine, naproxen, and an early compound hit (phthalazine 1). These studies illustrated the low preparative efficacy of biotransformations and the inability of chemical methods to oxidize complex pharmaceuticals. We also disclose an aerobic catalytic protocole (CuI/air) to oxidize tertiary amines and benzylic CH's in drugs. The reaction tolerates a broad range of functionalities and displays a high level of chemoselectivity, which is not generally explained by the strength of the C-H bonds but by the individual structural chemotype. This study represents a first step toward establishing a chemical toolkit (chemotransformations) that can selectively oxidize C-H bonds in complex pharmaceuticals and rapidly deliver drug metabolites.

  15. Quantum chemical analysis of Со2+ aqua complexes electrochemical reduction

    Directory of Open Access Journals (Sweden)

    Viktor F. Vargalyuk

    2017-11-01

    Full Text Available Based on the analysis of quantum chemical calculations results (GAMESS, density functional theory, B3LYP method as to [Co(H2On]z(H2O6–n clusters for z = 0, 1, 2 and n=1÷6, it has been demonstrated that electrochemical reduction of [Co(H2O6]2+ aqua complexes runs stage-wise. At the first stage, an electron injected into the [Co(H2O6]2+ complex is entirely located in the orbital of the central atom, as z(Co herewith changes from +1.714 е to +0.777 е. The weakening of Со–ОН2 bonds leads to decomposition of resulting [Co(H2O6]+ particles into two energetically related forms – [Co(H2O4]+ and [Co(H2O3]+. Further reduction of these intermediates runs differently. Electron injection into the [Co(H2O3]+ intermediate terminatesthe transition of Со2+-ions to Со0 z(Co= –0.264 е. This process is accompanied by rapid decomposition of [Co(H2O3]0 product into monohydrate atom of cobalt Со(Н2О. On the contrary, electron injection into the [Co(H2O4]+ intermediate leads to emergence of a specific structure – [Co+(H2O–(Н2О3]¹0, whereby the electron is located in the atoms of cobalt only by 28%, and by 72% in cobalt-coordinated water molecules, clearly focusing on one of the. In this molecule, z(H2O changes from +0.148 е to –0.347 е. There is an assumption that a non-equilibrium [Co+(H2O–(Н2О3]0¹ form transits to [Co(ОH(Н2О3]0 hydroxo-form, which further disproportionates turning into Co(ОH2 hydroxide. In order to reduce the impact of this unfavorable reaction pathway on the overall reaction rate Со2+ + 2ē = Со0, we suggest raising the temperature to ensure complete dissociation of [Co(H2O4]+ to [Co(H2O3]+.

  16. Exploring the oxidation and iron binding profile of a cyclodextrin encapsulated quercetin complex unveiled a controlled complex dissociation through a chemical stimulus.

    Science.gov (United States)

    Diamantis, Dimitrios A; Ramesova, Sarka; Chatzigiannis, Christos M; Degano, Ilaria; Gerogianni, Paraskevi S; Karadima, Constantina; Perikleous, Sonia; Rekkas, Dimitrios; Gerothanassis, Ioannis P; Galaris, Dimitrios; Mavromoustakos, Thomas; Valsami, Georgia; Sokolova, Romana; Tzakos, Andreas G

    2018-06-07

    Flavonoids possess a rich polypharmacological profile and their biological role is linked to their oxidation state protecting DNA from oxidative stress damage. However, their bioavailability is hampered due to their poor aqueous solubility. This can be surpassed through encapsulation to supramolecular carriers as cyclodextrin (CD). A quercetin- 2HP-β-CD complex has been formerly reported by us. However, once the flavonoid is in its 2HP-β-CD encapsulated state its oxidation potential, its decomplexation mechanism, its potential to protect DNA damage from oxidative stress remained elusive. To unveil this, an array of biophysical techniques was used. The quercetin-2HP-β-CD complex was evaluated through solubility and dissolution experiments, electrochemical and spectroelectrochemical studies (Cyclic Voltammetry) UV-Vis spectroscopy, HPLC-ESI-MS/MS and HPLC-DAD, fluorescence spectroscopy, NMR Spectroscopy, theoretical calculations (density functional theory (DFT)) and biological evaluation of the protection offered against H 2 O 2 -induced DNA damage. Encapsulation of quercetin inside the supramolecule's cavity enhanced its solubility and oxidation profile is retained in its encapsulated state. Although the protective ability of the quercetin-2HP-β-CD complex against H 2 O 2 was diminished, iron serves as a chemical stimulus to dissociate the complex and release quercetin. We found that in a quercetin-2HP-β-CD inclusion complex quercetin retains its oxidation profile similarly to its native state, while iron can operate as a chemical stimulus to release quercetin from its host cavity. The oxidation profile of a natural product once it is encapsulated in a supramolecular cyclodextrin carrier as also it was discovered that decomplexation can be triggered by a chemical stimulus. Copyright © 2018. Published by Elsevier B.V.

  17. Empirical, thermodynamic and quantum-chemical investigations of inclusion complexation between flavanones and (2-hydroxypropyl)-cyclodextrins.

    Science.gov (United States)

    Liu, Benguo; Li, Wei; Nguyen, Tien An; Zhao, Jian

    2012-09-15

    The inclusion complexation of (2-hydroxypropyl)-cyclodextrins with flavanones was investigated by phase solubility measurements, as well as thermodynamic and quantum chemical methods. Inclusion complexes were formed between (2-hydroxypropyl)-α-cyclodextrin (HP-α-CD), (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD), (2-hydroxypropyl)-γ-cyclodextrin (HP-γ-CD) and β-cyclodextrin (β-CD) and four flavanones (naringenin, naringin, hesperetin and dihydromyricetin) in aqueous solutions and their phase solubility was determined. For all the flavanones, the stability constants of their complexes formed with different CDs followed the rank order: HP-β-CD (MW 1540)>HP-β-CD (MW 1460)>HP-β-CD (MW 1380)>β-CD>HP-γ-CD>HP-α-CD. Experimental results and quantum chemical calculations showed that the ability of flavanones to form inclusion complex with (2-hydroxypropyl)-cyclodextrins was determined by both the steric effect and hydrophobicity of the flavanones. For flavanones that have similar molecular volumes, the hydrophobicity of the molecule was the main determining factor of its ability to form inclusion complexes with HP-β-CD, and the hydrophobicity parameter Log P is highly correlated with the stability constant of the complexes. Results of thermodynamic study demonstrated that hydrophobic interaction is the main driving force for the formation process of the flavanone-CD inclusion complexes. Quantum chemical analysis of the most active hydroxyl groups and HOMO (the highest occupied molecular orbital) showed that the B ring of the flavanones was most likely involved in hydrogen bonding with the side groups in the cavity of the CDs, through which the inclusion complex was stabilised. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. CHEMICAL ABUNDANCES IN NGC 5053: A VERY METAL-POOR AND DYNAMICALLY COMPLEX GLOBULAR CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    Boberg, Owen M.; Friel, Eileen D.; Vesperini, Enrico [Astronomy Department, Indiana University, Bloomington, IN 47405 (United States)

    2015-05-10

    NGC 5053 provides a rich environment to test our understanding of the complex evolution of globular clusters (GCs). Recent studies have found that this cluster has interesting morphological features beyond the typical spherical distribution of GCs, suggesting that external tidal effects have played an important role in its evolution and current properties. Additionally, simulations have shown that NGC 5053 could be a likely candidate to belong to the Sagittarius dwarf galaxy (Sgr dSph) stream. Using the Wisconsin–Indiana–Yale–NOAO–Hydra multi-object spectrograph, we have collected high quality (signal-to-noise ratio ∼ 75–90), medium-resolution spectra for red giant branch stars in NGC 5053. Using these spectra we have measured the Fe, Ca, Ti, Ni, Ba, Na, and O abundances in the cluster. We measure an average cluster [Fe/H] abundance of −2.45 with a standard deviation of 0.04 dex, making NGC 5053 one of the most metal-poor GCs in the Milky Way (MW). The [Ca/Fe], [Ti/Fe], and [Ba/Fe] we measure are consistent with the abundances of MW halo stars at a similar metallicity, with alpha-enhanced ratios and slightly depleted [Ba/Fe]. The Na and O abundances show the Na–O anti-correlation found in most GCs. From our abundance analysis it appears that NGC 5053 is at least chemically similar to other GCs found in the MW. This does not, however, rule out NGC 5053 being associated with the Sgr dSph stream.

  19. Chemical Abundances in NGC 5053: A Very Metal-poor and Dynamically Complex Globular Cluster

    Science.gov (United States)

    Boberg, Owen M.; Friel, Eileen D.; Vesperini, Enrico

    2015-05-01

    NGC 5053 provides a rich environment to test our understanding of the complex evolution of globular clusters (GCs). Recent studies have found that this cluster has interesting morphological features beyond the typical spherical distribution of GCs, suggesting that external tidal effects have played an important role in its evolution and current properties. Additionally, simulations have shown that NGC 5053 could be a likely candidate to belong to the Sagittarius dwarf galaxy (Sgr dSph) stream. Using the Wisconsin-Indiana-Yale-NOAO-Hydra multi-object spectrograph, we have collected high quality (signal-to-noise ratio ˜ 75-90), medium-resolution spectra for red giant branch stars in NGC 5053. Using these spectra we have measured the Fe, Ca, Ti, Ni, Ba, Na, and O abundances in the cluster. We measure an average cluster [Fe/H] abundance of -2.45 with a standard deviation of 0.04 dex, making NGC 5053 one of the most metal-poor GCs in the Milky Way (MW). The [Ca/Fe], [Ti/Fe], and [Ba/Fe] we measure are consistent with the abundances of MW halo stars at a similar metallicity, with alpha-enhanced ratios and slightly depleted [Ba/Fe]. The Na and O abundances show the Na-O anti-correlation found in most GCs. From our abundance analysis it appears that NGC 5053 is at least chemically similar to other GCs found in the MW. This does not, however, rule out NGC 5053 being associated with the Sgr dSph stream.

  20. ReactionPredictor: prediction of complex chemical reactions at the mechanistic level using machine learning.

    Science.gov (United States)

    Kayala, Matthew A; Baldi, Pierre

    2012-10-22

    Proposing reasonable mechanisms and predicting the course of chemical reactions is important to the practice of organic chemistry. Approaches to reaction prediction have historically used obfuscating representations and manually encoded patterns or rules. Here we present ReactionPredictor, a machine learning approach to reaction prediction that models elementary, mechanistic reactions as interactions between approximate molecular orbitals (MOs). A training data set of productive reactions known to occur at reasonable rates and yields and verified by inclusion in the literature or textbooks is derived from an existing rule-based system and expanded upon with manual curation from graduate level textbooks. Using this training data set of complex polar, hypervalent, radical, and pericyclic reactions, a two-stage machine learning prediction framework is trained and validated. In the first stage, filtering models trained at the level of individual MOs are used to reduce the space of possible reactions to consider. In the second stage, ranking models over the filtered space of possible reactions are used to order the reactions such that the productive reactions are the top ranked. The resulting model, ReactionPredictor, perfectly ranks polar reactions 78.1% of the time and recovers all productive reactions 95.7% of the time when allowing for small numbers of errors. Pericyclic and radical reactions are perfectly ranked 85.8% and 77.0% of the time, respectively, rising to >93% recovery for both reaction types with a small number of allowed errors. Decisions about which of the polar, pericyclic, or radical reaction type ranking models to use can be made with >99% accuracy. Finally, for multistep reaction pathways, we implement the first mechanistic pathway predictor using constrained tree-search to discover a set of reasonable mechanistic steps from given reactants to given products. Webserver implementations of both the single step and pathway versions of Reaction

  1. Generation of Complex Karstic Conduit Networks with a Hydro-chemical Model

    Science.gov (United States)

    De Rooij, R.; Graham, W. D.

    2016-12-01

    The discrete-continuum approach is very well suited to simulate flow and solute transport within karst aquifers. Using this approach, discrete one-dimensional conduits are embedded within a three-dimensional continuum representative of the porous limestone matrix. Typically, however, little is known about the geometry of the karstic conduit network. As such the discrete-continuum approach is rarely used for practical applications. It may be argued, however, that the uncertainty associated with the geometry of the network could be handled by modeling an ensemble of possible karst conduit networks within a stochastic framework. We propose to generate stochastically realistic karst conduit networks by simulating the widening of conduits as caused by the dissolution of limestone over geological relevant timescales. We illustrate that advanced numerical techniques permit to solve the non-linear and coupled hydro-chemical processes efficiently, such that relatively large and complex networks can be generated in acceptable time frames. Instead of specifying flow boundary conditions on conduit cells to recharge the network as is typically done in classical speleogenesis models, we specify an effective rainfall rate over the land surface and let model physics determine the amount of water entering the network. This is advantageous since the amount of water entering the network is extremely difficult to reconstruct, whereas the effective rainfall rate may be quantified using paleoclimatic data. Furthermore, we show that poorly known flow conditions may be constrained by requiring a realistic flow field. Using our speleogenesis model we have investigated factors that influence the geometry of simulated conduit networks. We illustrate that our model generates typical branchwork, network and anastomotic conduit systems. Flow, solute transport and water ages in karst aquifers are simulated using a few illustrative networks.

  2. Combining chemoinformatics with bioinformatics: in silico prediction of bacterial flavor-forming pathways by a chemical systems biology approach "reverse pathway engineering".

    Science.gov (United States)

    Liu, Mengjin; Bienfait, Bruno; Sacher, Oliver; Gasteiger, Johann; Siezen, Roland J; Nauta, Arjen; Geurts, Jan M W

    2014-01-01

    The incompleteness of genome-scale metabolic models is a major bottleneck for systems biology approaches, which are based on large numbers of metabolites as identified and quantified by metabolomics. Many of the revealed secondary metabolites and/or their derivatives, such as flavor compounds, are non-essential in metabolism, and many of their synthesis pathways are unknown. In this study, we describe a novel approach, Reverse Pathway Engineering (RPE), which combines chemoinformatics and bioinformatics analyses, to predict the "missing links" between compounds of interest and their possible metabolic precursors by providing plausible chemical and/or enzymatic reactions. We demonstrate the added-value of the approach by using flavor-forming pathways in lactic acid bacteria (LAB) as an example. Established metabolic routes leading to the formation of flavor compounds from leucine were successfully replicated. Novel reactions involved in flavor formation, i.e. the conversion of alpha-hydroxy-isocaproate to 3-methylbutanoic acid and the synthesis of dimethyl sulfide, as well as the involved enzymes were successfully predicted. These new insights into the flavor-formation mechanisms in LAB can have a significant impact on improving the control of aroma formation in fermented food products. Since the input reaction databases and compounds are highly flexible, the RPE approach can be easily extended to a broad spectrum of applications, amongst others health/disease biomarker discovery as well as synthetic biology.

  3. Chemical Activation of the Hypoxia-Inducible Factor Reversibly Reduces Tendon Stem Cell Proliferation, Inhibits Their Differentiation, and Maintains Cell Undifferentiation.

    Science.gov (United States)

    Menon, Alessandra; Creo, Pasquale; Piccoli, Marco; Bergante, Sonia; Conforti, Erika; Banfi, Giuseppe; Randelli, Pietro; Anastasia, Luigi

    2018-01-01

    Adult stem cell-based therapeutic approaches for tissue regeneration have been proposed for several years. However, adult stem cells are usually limited in number and difficult to be expanded in vitro, and they usually tend to quickly lose their potency with passages, as they differentiate and become senescent. Culturing stem cells under reduced oxygen tensions (below 21%) has been proposed as a tool to increase cell proliferation, but many studies reported opposite effects. In particular, cell response to hypoxia seems to be very stem cell type specific. Nonetheless, it is clear that a major role in this process is played by the hypoxia inducible factor (HIF), the master regulator of cell response to oxygen deprivation, which affects cell metabolism and differentiation. Herein, we report that a chemical activation of HIF in human tendon stem cells reduces their proliferation and inhibits their differentiation in a reversible and dose-dependent manner. These results support the notion that hypoxia, by activating HIF, plays a crucial role in preserving stem cells in an undifferentiated state in the "hypoxic niches" present in the tissue in which they reside before migrating in more oxygenated areas to heal a damaged tissue.

  4. Chemical Activation of the Hypoxia-Inducible Factor Reversibly Reduces Tendon Stem Cell Proliferation, Inhibits Their Differentiation, and Maintains Cell Undifferentiation

    Directory of Open Access Journals (Sweden)

    Alessandra Menon

    2018-01-01

    Full Text Available Adult stem cell-based therapeutic approaches for tissue regeneration have been proposed for several years. However, adult stem cells are usually limited in number and difficult to be expanded in vitro, and they usually tend to quickly lose their potency with passages, as they differentiate and become senescent. Culturing stem cells under reduced oxygen tensions (below 21% has been proposed as a tool to increase cell proliferation, but many studies reported opposite effects. In particular, cell response to hypoxia seems to be very stem cell type specific. Nonetheless, it is clear that a major role in this process is played by the hypoxia inducible factor (HIF, the master regulator of cell response to oxygen deprivation, which affects cell metabolism and differentiation. Herein, we report that a chemical activation of HIF in human tendon stem cells reduces their proliferation and inhibits their differentiation in a reversible and dose-dependent manner. These results support the notion that hypoxia, by activating HIF, plays a crucial role in preserving stem cells in an undifferentiated state in the “hypoxic niches” present in the tissue in which they reside before migrating in more oxygenated areas to heal a damaged tissue.

  5. Facile and reversible formation of iron(III)-oxo-cerium(IV) adducts from nonheme oxoiron(IV) complexes and cerium(III)

    Energy Technology Data Exchange (ETDEWEB)

    Draksharapu, Apparao; Rasheed, Waqas; Klein, Johannes E.M.N.; Que, Lawrence Jr. [Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN (United States)

    2017-07-24

    Ceric ammonium nitrate (CAN) or Ce{sup IV}(NH{sub 4}){sub 2}(NO{sub 3}){sub 6} is often used in artificial water oxidation and generally considered to be an outer-sphere oxidant. Herein we report the spectroscopic and crystallographic characterization of [(N4Py)Fe{sup III}-O-Ce{sup IV}(OH{sub 2})(NO{sub 3}){sub 4}]{sup +} (3), a complex obtained from the reaction of [(N4Py)Fe{sup II}(NCMe)]{sup 2+} with 2 equiv CAN or [(N4Py)Fe{sup IV}=O]{sup 2+} (2) with Ce{sup III}(NO{sub 3}){sub 3} in MeCN. Surprisingly, the formation of 3 is reversible, the position of the equilibrium being dependent on the MeCN/water ratio of the solvent. These results suggest that the Fe{sup IV} and Ce{sup IV} centers have comparable reduction potentials. Moreover, the equilibrium entails a change in iron spin state, from S=1 Fe{sup IV} in 2 to S=5/2 in 3, which is found to be facile despite the formal spin-forbidden nature of this process. This observation suggests that Fe{sup IV}=O complexes may avail of reaction pathways involving multiple spin states having little or no barrier. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Analysis of metallic nanoparticles and their ionic counterparts in complex matrix by reversed-phase liquid chromatography coupled to ICP-MS.

    Science.gov (United States)

    Yang, Yuan; Luo, Li; Li, Hai-Pu; Wang, Qiang; Yang, Zhao-Guang; Qu, Zhi-Peng; Ding, Ru

    2018-05-15

    Developing quantification and characterization methodology for metallic nanoparticles (MNPs) and their ionic component in complex matrix are crucial for the evaluation of their environmental behavior and health risks to humans. In this study, reversed phase high performance liquid chromatography combined ICP-MS was established for the characterization of MNPs in complex matrix. The ionic component could be separated from NPs with the optimized parameters of aqueous mobile phase. Good linear relationship between average diameter and retention time of NPs was obtained using HPLC-ICP-MS and the size smaller than 40 nm could be determined with this method, the detected results were in accordance with TEM results. The low detection limit of AuNPs and Au(Ⅲ) (both in sub-μg/L level) showed that this method was promising for the characterization of AuNPs and Au(Ⅲ) in environmental water. The mass concentration of ionic Au(Ⅲ) in environmental water could be detected using the proposed HPLC-ICP-MS and the concentration of AuNPs was obtained by subtracting the Au(Ⅲ) concentration from the total Au (The concentration of total Au was detected by ICP-MS after microwave digestion). Furthermore this proposed HPLC-ICP-MS method and single particle-ICPMS (SP-ICP-MS) was used for the analysis of the Ag speciation in commercial antibacterial products. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Reverse Osmosis

    Indian Academy of Sciences (India)

    many applications, one of which is desalination of seawater. The inaugural Nobel Prize in Chemistry was awarded in 1901 to van 't Hoff for his seminal work in this area. The present article explains the principle of osmosis and reverse osmosis. Osmosis and Reverse Osmosis. As the name suggests, reverse osmosis is the ...

  8. Monoamines stimulate sex reversal in the saddleback wrasse.

    Science.gov (United States)

    Larson, Earl T; Norris, David O; Gordon Grau, E; Summers, Cliff H

    2003-02-15

    Monoamine neurotransmitters (norepinephrine, dopamine, and serotonin) play an important role in reproduction and sexual behavior throughout the vertebrates. They are the first endogenous chemical signals in the regulation of the hypothalamo-pituitary-gonadal (HPG) axis. In teleosts with behavioral sex determination, much is known about behavioral cues that induce sex reversal. The cues are social, processed via the visual system and depend on the ratio of females to males in the population. The mechanisms by which these external behavioral cues are converted to an internal chemical regulatory process are largely unknown. The protogynous Hawaiian saddleback wrasse, Thalassoma duperrey, was used to investigate the biological pathway mediating the conversion of a social cue into neuroendocrine events regulating sex reversal. Because monoamines play an important role in the regulation of the HPG axis, they were selected as likely candidates for such a conversion. To determine if monoamines could affect sex reversal, drugs affecting monoamines were used in an attempt to either induce sex reversal under non-permissive conditions, or prevent sex reversal under permissive conditions. Increasing norepinephrine or blocking dopamine or serotonin lead to sex reversal in experimental animals under non-permissive conditions. Increasing serotonin blocked sex reversal under permissive conditions, while blocking dopamine or norepinephrine retarded the process. The results presented here demonstrate that monoamines contribute significantly to the control sex reversal. Norepinephrine stimulates initiation and completion of gonadal sex of reversal as well as color change perhaps directly via its effects on the HPG axis. Dopamine exercises inhibitory action on the initiation of sex reversal while 5-HT inhibits both initiation and completion of sex reversal. The serotonergic system appears to be an integral part of the pathway mediating the conversion of a social cue into a

  9. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  10. Inversion of exchange bias and complex magnetization reversal in full-nitride epitaxial γ′-Fe{sub 4}N/CoN bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.R. [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072 (China); Mi, W.B., E-mail: miwenbo@tju.edu.cn [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072 (China); Wang, X.C. [Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384, China (China); Bai, H.L. [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072 (China)

    2015-04-01

    Exchange bias has been observed in the full-nitride epitaxial γ′-Fe{sub 4}N/CoN bilayers. With the increase of temperature, the sign of exchange bias (EB) is inverse, which is independent on the cooling field and training effect. This novel behavior appears in the bilayers with different CoN and γ′-Fe{sub 4}N thicknesses. The inversion of EB sign not only occurs at low temperatures, but also takes place even at 200 K for the 10 and 12 nm thick CoN layer. With the decreased γ′-Fe{sub 4}N layer thickness, the inversion temperature of EB sign shows a roughly increased tendency. For the bilayer with a 4 nm-thick γ′-Fe{sub 4}N, the interfacial magnetization reversal presents a complex trend, which is considered as the combined actions of the disordered ferromagnetic spins and various competed magnetic structures. This new manifestation of EB has been discussed in terms of the complicated interfacial spin structures and frustration effects due to the competition between the ferromagnetic and antiferromagnetic exchange interactions at the interface. - Highlights: • Exchange bias (EB) sign reverses from negative to positive with increasing temperature in epitaxial γ′-Fe{sub 4}N/CoN bilayers. • The positive EB can be attributed to the antiferromagnetic interfacial coupling and frustrated interfacial spin structures. • The EB transition temperature is not monotonically dependent on CoN thickness t{sub CoN}. • For a 4-nm γ′-Fe{sub 4}N, the unusual hysteresis loops are observed.

  11. The Complexities of Interpreting Reversible Elevated Serum Creatinine Levels in Drug Development: Does a Correlation with Inhibition of Renal Transporters Exist?

    Science.gov (United States)

    Chu, Xiaoyan; Bleasby, Kelly; Chan, Grace Hoyee; Nunes, Irene; Evers, Raymond

    2016-09-01

    In humans, creatinine is formed by a multistep process in liver and muscle and eliminated via the kidney by a combination of glomerular filtration and active transport. Based on current evidence, creatinine can be taken up into renal proximal tubule cells by the basolaterally localized organic cation transporter 2 (OCT2) and the organic anion transporter 2, and effluxed into the urine by the apically localized multidrug and toxin extrusion protein 1 (MATE1) and MATE2K. Drug-induced elevation of serum creatinine (SCr) and/or reduced creatinine renal clearance is routinely used as a marker for acute kidney injury. Interpretation of elevated SCr can be complex, because such increases can be reversible and explained by inhibition of renal transporters involved in active secretion of creatinine or other secondary factors, such as diet and disease state. Distinction between these possibilities is important from a drug development perspective, as increases in SCr can result in the termination of otherwise efficacious drug candidates. In this review, we discuss the challenges associated with using creatinine as a marker for kidney damage. Furthermore, to evaluate whether reversible changes in SCr can be predicted prospectively based on in vitro transporter inhibition data, an in-depth in vitro-in vivo correlation (IVIVC) analysis was conducted for 16 drugs with in-house and literature in vitro transporter inhibition data for OCT2, MATE1, and MATE2K, as well as total and unbound maximum plasma concentration (Cmax and Cmax,u) data measured in the clinic. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  12. Reversible blockade of complex I or inhibition of PKCβ reduces activation and mitochondria translocation of p66Shc to preserve cardiac function after ischemia.

    Directory of Open Access Journals (Sweden)

    Meiying Yang

    Full Text Available Excess mitochondrial reactive oxygen species (mROS play a vital role in cardiac ischemia reperfusion (IR injury. P66Shc, a splice variant of the ShcA adaptor protein family, enhances mROS production by oxidizing reduced cytochrome c to yield H2O2. Ablation of p66Shc protects against IR injury, but it is unknown if and when p66Shc is activated during cardiac ischemia and/or reperfusion and if attenuating complex I electron transfer or deactivating PKCβ alters p66Shc activation during IR is associated with cardioprotection.Isolated guinea pig hearts were perfused and subjected to increasing periods of ischemia and reperfusion with or without amobarbital, a complex I blocker, or hispidin, a PKCβ inhibitor. Phosphorylation of p66Shc at serine 36 and levels of p66Shc in mitochondria and cytosol were measured. Cardiac functional variables and redox states were monitored online before, during and after ischemia. Infarct size was assessed in some hearts after 120 min reperfusion.Phosphorylation of p66Shc and its translocation into mitochondria increased during reperfusion after 20 and 30 min ischemia, but not during ischemia only, or during 5 or 10 min ischemia followed by 20 min reperfusion. Correspondingly, cytosolic p66Shc levels decreased during these ischemia and reperfusion periods. Amobarbital or hispidin reduced phosphorylation of p66Shc and its mitochondrial translocation induced by 30 min ischemia and 20 min reperfusion. Decreased phosphorylation of p66Shc by amobarbital or hispidin led to better functional recovery and less infarction during reperfusion.Our results show that IR activates p66Shc and that reversible blockade of electron transfer from complex I, or inhibition of PKCβ activation, decreases p66Shc activation and translocation and reduces IR damage. These observations support a novel potential therapeutic intervention against cardiac IR injury.

  13. A Cost-Effectiveness Analysis of Reverse Total Shoulder Arthroplasty versus Hemiarthroplasty for the Management of Complex Proximal Humeral Fractures in the Elderly.

    Science.gov (United States)

    Osterhoff, Georg; O'Hara, Nathan N; D'Cruz, Jennifer; Sprague, Sheila A; Bansback, Nick; Evaniew, Nathan; Slobogean, Gerard P

    2017-03-01

    There is ongoing debate regarding the optimal surgical treatment of complex proximal humeral fractures in elderly patients. To evaluate the cost-effectiveness of reverse total shoulder arthroplasty (RTSA) compared with hemiarthroplasty (HA) in the management of complex proximal humeral fractures, using a cost-utility analysis. On the basis of data from published literature, a cost-utility analysis was conducted using decision tree and Markov modeling. A single-payer perspective, with a willingness-to-pay (WTP) threshold of Can$50,000 (Canadian dollars), and a lifetime time horizon were used. The incremental cost-effectiveness ratio (ICER) was used as the study's primary outcome measure. In comparison with HA, the incremental cost per quality-adjusted life-year gained for RTSA was Can$13,679. One-way sensitivity analysis revealed the model to be sensitive to the RTSA implant cost and the RTSA procedural cost. The ICER of Can$13,679 is well below the WTP threshold of Can$50,000, and probabilistic sensitivity analysis demonstrated that 92.6% of model simulations favored RTSA. Our economic analysis found that RTSA for the treatment of complex proximal humeral fractures in the elderly is the preferred economic strategy when compared with HA. The ICER of RTSA is well below standard WTP thresholds, and its estimate of cost-effectiveness is similar to other highly successful orthopedic strategies such as total hip arthroplasty for the treatment of hip arthritis. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  14. Evaluating exposures to complex mixtures of chemicals during a new production process in the plastics industry

    NARCIS (Netherlands)

    Meijster, T.; Burstyn, I.; Wendel de Joode, B. van; Posthumus, M.A.; Kromhout, H.

    2004-01-01

    The goal of this study was to monitor emission of chemicals at a factory where plastics products were fabricated by a new robotic (impregnated tape winding) production process. Stationary and personal air measurements were taken to determine which chemicals were released and at what concentrations.

  15. Evaluating Exposures to Complex Mixtures of Chemicals During a New Production Process in the Plastics Industry

    NARCIS (Netherlands)

    Meijster, T.; Burstyn, I.; Wendel de Joode, van B.; Posthumus, M.A.; Kromhout, H.

    2004-01-01

    The goal of this study was to monitor emission of chemicals at a factory where plastics products were fabricated by a new robotic (impregnated tape winding) production process. Stationary and personal air measurements were taken to determine which chemicals were released and at what concentrations.

  16. Synthesis, characterisation and chemical reactivity of some new binuclear dioxouranium(VI) complexes derived from organic diazo compounds (Preprint No. CT-33)

    International Nuclear Information System (INIS)

    Pujar, M.A.; Pirgonde, B.R.

    1988-02-01

    A new series of binuclear dioxouranium(VI) complexes of polydentatate diazo compounds have been synthesised and characterised adequately by analysis, physio-chemical techniques and reactivity of these complexes. The location of bonding site of ligands, stability of complexes and status of U-O bond and probable structures of these complexes have been discussed. (author). 10 refs

  17. Synthesis, physico-chemical characterization and biological activity of 2-aminobenzimidazole complexes with different metal ions

    Directory of Open Access Journals (Sweden)

    Podunavac-Kuzmanović Sanja O.

    2004-01-01

    Full Text Available Complexes of 2-aminobenzimidazole (L with nitrates of cobalt(II nickel(II, copper (II, zinc(II and silver(I were synthesized. The molar ratio metal:ligand in the reaction of the complex formation was 1:2. It should be noticed, that the reaction of all the metal salts yielded bis(ligand complexes of the general formula M(L2(NO32 × nH2O (M=Co, Ni Cu, Zn or Ag; n=0, 1, 2 or 6. The complexes were characterized by elemental analysis of the metal, molar conductivity, magnetic susceptibility measurements and IR spectra. Co(II, Ni(II and Cu(II complexes behave as non-electrolytes, whilst Zn(II and Ag(I are 1:1 electrolytes. Cu(II complex has a square-planar stereochemistry, Ag(I complex is linear, whilst the Co(II, Ni(II and Zn(II complexes have a tetrahedral configuration. In all the complexes ligand is coordinated by participation of the pyridine nitrogen of the benzimidazole ring. The antimicrobial activity of the ligand and its complexes against Pseudomonas aeruginosa, Bacillus sp. Staphylococcus aureus and Saccharomyces cerevisiae was investigated. The effect of metal on the ligand antimicrobial activity is discussed.

  18. A systems engineering approach to manage the complexity in sustainable chemical product-process design

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    This paper provides a perspective on model-data based solution approaches for chemical product-process design, which consists of finding the identity of the candidate chemical product, designing the process that can sustainably manufacture it and verifying the performance of the product during...... application. The chemical product tree is potentially very large and a wide range of options exist for selecting the product to make, the raw material to use as well as the processing route to employ. It is shown that systematic computer-aided methods and tools integrated within a model-data based design...

  19. Thermodynamic method for obtaining the solubilities of complex medium-sized chemicals in pure and mixed solvents

    DEFF Research Database (Denmark)

    Abildskov, Jens; O'Connell, J.P.

    2005-01-01

    This paper extends our previous simplified approach to using group contribution methods and limited data to determine differences in solubility of sparingly soluble complex chemicals as the solvent is changed. New applications include estimating temperature dependence and the effect of adding cos....... Though we present no new solution theory, the paper shows an especially efficient use of thermodynamic models for solvent and cosolvent selection for product formulations. Examples and discussion of applications are given. (c) 2004 Elsevier B.V. All rights reserved.......This paper extends our previous simplified approach to using group contribution methods and limited data to determine differences in solubility of sparingly soluble complex chemicals as the solvent is changed. New applications include estimating temperature dependence and the effect of adding...

  20. Chemical data and variation diagrams of igneous rocks from the Timber Mountain-Oasis Valley Caldera Complex, southern Nevada

    Science.gov (United States)

    Quinlivan, W.D.; Byers, F.M.

    1977-01-01

    Silica variation diagrams presented here are based on 162 chemical analyses of tuffs, lavas, and intrusives, representative of volcanic centers of the Timber Mountain-Oasis Valley caldera complex and cogenetic rocks of the Silent Canyon ca1dera. Most of the volcanic units sampled are shown on the U.S. Geological Survey geologic map of the Timber Mountain caldera area (I-891) and are described in U.S. Geological Survey Professional Paper 919. Early effusives of the complex, although slightly altered, are probably chemically, and petrographically, more like the calc-alkalic Fraction Tuff (Miocene) of the northern Nellis Air Force Base Bombing and Gunnery Range to the north, whereas effusives of later Miocene age, such as the Paintbrush and Timber Mountain Tuffs, are alkali-calcic.

  1. Use of the nonsteady monotonic heating method for complex determination of thermophysical properties of chemically reacting mixture in the case of non-equilibrium proceeding of the chemical reaction

    International Nuclear Information System (INIS)

    Serebryanyj, G.Z.

    1984-01-01

    Theoretical analysis is made for the monotonic heating method as applied for complex determination of thermophysical properties of chemically reacting gases. The possibility is shown of simultaneous determination of frozen and equilibrium heat capacity, frozen and equilibrium heat conduction provided non-equilibrium occuring of the reaction in the wide range of temperatures and pressures. The monotonic heating method can be used for complex determination of thermophysical properties of chemically reacting systems in case of non-equilibrium proceeding of the chemical reaction

  2. Chemical complexity induced by efficient ice evaporation in the Barnard 5 molecular cloud

    OpenAIRE

    Taquet, Vianney; Wirström, Eva; Charnley, Steven B.; Faure, Alexandre; López-Sepulcre, Ana; Persson, Carina M.

    2017-01-01

    Cold gas-phase water has recently been detected in a cold dark cloud, Barnard 5 located in the Perseus complex, by targeting methanol peaks as signposts for ice mantle evaporation. Observed morphology and abundances of methanol and water are consistent with a transient non-thermal evaporation process only affecting the outermost ice mantle layers, possibly triggering a more complex chemistry. We present the detection of the Complex Organic Molecules (COMs) acetaldehyde and methyl formate as w...

  3. Association between chemical pattern in breast milk and congenital cryptorchidism: modelling of complex human exposures

    DEFF Research Database (Denmark)

    Krysiak-Baltyn, Konrad; Toppari, J.; Skakkebaek, N. E.

    2012-01-01

    , polybrominated biphenyls and organochlorine pesticides. Computational analysis of the data was performed using logistic regression and three multivariate machine learning classifiers. Furthermore, we performed systems biology analysis to explore the chemical influence on a molecular level. After correction...... and cryptorchidism than Finnish samples. Moreover, PCBs were indicated as having a protective effect within the Danish cohort, which was supported by molecular data recovered through systems biology. Our results lend further support to the hypothesis that the mixture of environmental chemicals may contribute...

  4. Syntheses, structural elucidation, thermal properties, theoretical quantum chemical studies (DFT and biological studies of barbituric–hydrazone complexes

    Directory of Open Access Journals (Sweden)

    Amina A. Soayed

    2015-03-01

    Full Text Available Condensation of barbituric acid with hydrazine hydrate yielded barbiturichydrazone (L which was characterized using IR, 1H NMR and mass spectra. The Co(II, Ni(II and Cu(II complexes derived from this ligand have been synthesized and structurally characterized by elemental analyses, spectroscopic methods (IR, UV–Vis and ESR and thermal analyses (TGA, DTG and DTA and the structures were further elucidated using quantum chemical density functional theory. Complexes of L were found to have the ML.nH2O stoichiometry with either tetrahedral or octahedral geometry. The ESR data showed the Cu(II complex to be in a tetragonal geometry. Theoretical investigation of the electronic structure of metal complexes at the TD-DFT/B3LYP level of theory has been carried out and discussed. The fundamental vibrational wavenumbers were calculated and a good agreement between observed and scaled calculated wavenumbers was achieved. Thermal studies were performed to deduce the stabilities of the ligand and complexes. Thermodynamic parameters, such as the order of reactions (n, activation energy ΔE∗, enthalpy of reaction ΔH∗ and entropy ΔS∗ were calculated from DTA curves using Horowitz–Metzger method. The ligand L and its complexes have been screened for their antifungal and antibacterial activities and were found to possess better biological activities compared to those of unsubstituted barbituric acid complexes.

  5. HYPER RECOMBINATION1 of the THO/TREX complex plays a role in controlling transcription of the REVERSION-TO-ETHYLENE SENSITIVITY1 gene in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Congyao Xu

    2015-02-01

    Full Text Available Arabidopsis REVERSION-TO-ETHYLENE SENSITIVITY1 (RTE1 represses ethylene hormone responses by promoting ethylene receptor ETHYLENE RESPONSE1 (ETR1 signaling, which negatively regulates ethylene responses. To investigate the regulation of RTE1, we performed a genetic screening for mutations that suppress ethylene insensitivity conferred by RTE1 overexpression in Arabidopsis. We isolated HYPER RECOMBINATION1 (HPR1, which is required for RTE1 overexpressor (RTE1ox ethylene insensitivity at the seedling but not adult stage. HPR1 is a component of the THO complex, which, with other proteins, forms the TRanscription EXport (TREX complex. In yeast, Drosophila, and humans, the THO/TREX complex is involved in transcription elongation and nucleocytoplasmic RNA export, but its role in plants is to be fully determined. We investigated how HPR1 is involved in RTE1ox ethylene insensitivity in Arabidopsis. The hpr1-5 mutation may affect nucleocytoplasmic mRNA export, as revealed by in vivo hybridization of fluorescein-labeled oligo(dT45 with unidentified mRNA in the nucleus. The hpr1-5 mutation reduced the total and nuclear RTE1 transcript levels to a similar extent, and RTE1 transcript reduction rate was not affected by hpr1-5 with cordycepin treatment, which prematurely terminates transcription. The defect in the THO-interacting TEX1 protein of TREX but not the mRNA export factor SAC3B also reduced the total and nuclear RTE1 levels. SERINE-ARGININE-RICH (SR proteins are involved mRNA splicing, and we found that SR protein SR33 co-localized with HPR1 in nuclear speckles, which agreed with the association of human TREX with the splicing machinery. We reveal a role for HPR1 in RTE1 expression during transcription elongation and less likely during export. Gene expression involved in ethylene signaling suppression was not reduced by the hpr1-5 mutation, which indicates selectivity of HPR1 for RTE1 expression affecting the consequent ethylene response. Thus

  6. KB-R7943, an inhibitor of the reverse Na+/Ca2+ exchanger, blocks N-methyl-D-aspartate receptor and inhibits mitochondrial complex I

    Science.gov (United States)

    Brustovetsky, Tatiana; Brittain, Matthew K; Sheets, Patrick L; Cummins, Theodore R; Pinelis, Vsevolod; Brustovetsky, Nickolay

    2011-01-01

    BACKGROUND AND PURPOSE An isothiourea derivative (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methane sulfonate (KB-R7943), a widely used inhibitor of the reverse Na+/Ca2+ exchanger (NCXrev), was instrumental in establishing the role of NCXrev in glutamate-induced Ca2+ deregulation in neurons. Here, the effects of KB-R7943 on N-methyl-D-aspartate (NMDA) receptors and mitochondrial complex I were tested. EXPERIMENTAL APPROACH Fluorescence microscopy, electrophysiological patch-clamp techniques and cellular respirometry with Seahorse XF24 analyzer were used with cultured hippocampal neurons; membrane potential imaging, respirometry and Ca2+ flux measurements were made in isolated rat brain mitochondria. KEY RESULTS KB-R7943 inhibited NCXrev with IC50= 5.7 ± 2.1 µM, blocked NMDAR-mediated ion currents, and inhibited NMDA-induced increase in cytosolic Ca2+ with IC50= 13.4 ± 3.6 µM but accelerated calcium deregulation and mitochondrial depolarization in glutamate-treated neurons. KB-R7943 depolarized mitochondria in a Ca2+-independent manner. Stimulation of NMDA receptors caused NAD(P)H oxidation that was coupled or uncoupled from ATP synthesis depending on the presence of Ca2+ in the bath solution. KB-R7943, or rotenone, increased NAD(P)H autofluorescence under resting conditions and suppressed NAD(P)H oxidation following glutamate application. KB-R7943 inhibited 2,4-dinitrophenol-stimulated respiration of cultured neurons with IC50= 11.4 ± 2.4 µM. With isolated brain mitochondria, KB-R7943 inhibited respiration, depolarized organelles and suppressed Ca2+ uptake when mitochondria oxidized complex I substrates but was ineffective when mitochondria were supplied with succinate, a complex II substrate. CONCLUSIONS AND IMPLICATIONS KB-R7943, in addition to NCXrev, blocked NMDA receptors in cultured hippocampal neurons and inhibited complex I in the mitochondrial respiratory chain. These findings are critical for the correct interpretation of experimental

  7. A method for simultaneous analysis of phytosterols and phytosterol esters in tobacco leaves using non aqueous reversed phase chromatography and atmospheric pressure chemical ionization mass spectrometry detector.

    Science.gov (United States)

    Ishida, Naoyuki

    2014-05-02

    While numerous analytical methods for phytosterols have been reported, the similar polarity and large molecules of phytosterol esters have made the methods lengthy and complicated. For this reason, an analytical method that could completely separate phytosterol esters including the higher fatty acids such as palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid in addition to phytosterols without preliminary separation was developed. The separation was accomplished by non-aqueous reversed phase chromatography technique using only acetone and acetonitrile. An atmospheric pressure chemical ionization/mass spectrometry detector configured at selected ion monitoring mode was hyphenated with the separation system to detect phytosterols and phytosterol esters. Twenty-four types of these were consequently separated and then identified with their authentic components. The calibration curve was drawn in the range of about 5 to 25,000 ng/mL with a regression coefficient over 0.999. The limit of detection and limit of quantification, respectively, ranged from 0.9 to 3.0 ng/mL and from 3.0 to 11.0 ng/mL. Recovery rates ranged from 80 to 120%. The quantification results were subjected to statistical analysis and hierarchical clustering analysis, and were used to determine the differences in the amounts of phytosterols and phytosterol esters across tobacco leaves. The newly developed method succeeded in clarifying the whole composition of phytosterols and phytosterol esters in tobacco leaves and in explaining compositional differences across the variety of tobacco leaves. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Clinical vocabulary as a boundary object in multidisciplinary care management of multiple chemical sensitivity, a complex and chronic condition.

    Science.gov (United States)

    Sampalli, Tara; Shepherd, Michael; Duffy, Jack

    2011-04-14

    Research has shown that accurate and timely communication between multidisciplinary clinicians involved in the care of complex and chronic health conditions is often challenging. The domain knowledge for these conditions is heterogeneous, with poorly categorized, unstructured, and inconsistent clinical vocabulary. The potential of boundary object as a technique to bridge communication gaps is explored in this study. A standardized and controlled clinical vocabulary was developed as a boundary object in the domain of a complex and chronic health condition, namely, multiple chemical sensitivity, to improve communication among multidisciplinary clinicians. A convenience sample of 100 patients with a diagnosis of multiple chemical sensitivity, nine multidisciplinary clinicians involved in the care of patients with multiple chemical sensitivity, and 36 clinicians in the community participated in the study. Eighty-two percent of the multidisciplinary and inconsistent vocabulary was standardized using the Systematized Nomenclature of Medicine - Clinical Terms (SNOMED(®) CT as a reference terminology. Over 80% of the multidisciplinary clinicians agreed on the overall usefulness of having a controlled vocabulary as a boundary object. Over 65% of clinicians in the community agreed on the overall usefulness of the vocabulary. The results from this study are promising and will be further evaluated in the domain of another complex chronic condition, ie, chronic pain. The study was conducted as a preliminary analysis for developing a boundary object in a heterogeneous domain of knowledge.

  9. Solute-solvent complex switching dynamics of chloroform between acetone and dimethylsulfoxide-two-dimensional IR chemical exchange spectroscopy.

    Science.gov (United States)

    Kwak, Kyungwon; Rosenfeld, Daniel E; Chung, Jean K; Fayer, Michael D

    2008-11-06

    Hydrogen bonds formed between C-H and various hydrogen bond acceptors play important roles in the structure of proteins and organic crystals, and the mechanisms of C-H bond cleavage reactions. Chloroform, a C-H hydrogen bond donor, can form weak hydrogen-bonded complexes with acetone and with dimethylsulfoxide (DMSO). When chloroform is dissolved in a mixed solvent consisting of acetone and DMSO, both types of hydrogen-bonded complexes exist. The two complexes, chloroform-acetone and chloroform-DMSO, are in equilibrium, and they rapidly interconvert by chloroform exchanging hydrogen bond acceptors. This fast hydrogen bond acceptor substitution reaction is probed using ultrafast two-dimensional infrared (2D-IR) vibrational echo chemical exchange spectroscopy. Deuterated chloroform is used in the experiments, and the 2D-IR spectrum of the C-D stretching mode is measured. The chemical exchange of the chloroform hydrogen bonding partners is tracked by observing the time-dependent growth of off-diagonal peaks in the 2D-IR spectra. The measured substitution rate is 1/30 ps for an acetone molecule to replace a DMSO molecule in a chloroform-DMSO complex and 1/45 ps for a DMSO molecule to replace an acetone molecule in a chloroform-acetone complex. Free chloroform exists in the mixed solvent, and it acts as a reactive intermediate in the substitution reaction, analogous to a SN1 type reaction. From the measured rates and the equilibrium concentrations of acetone and DMSO, the dissociation rates for the chloroform-DMSO and chloroform-acetone complexes are found to be 1/24 ps and 1/5.5 ps, respectively. The difference between the measured rate for the complete substitution reaction and the rate for complex dissociation corresponds to the diffusion limited rate. The estimated diffusion limited rate agrees well with the result from a Smoluchowski treatment of diffusive reactions.

  10. Reversible Heterolytic Cleavage of the H-H Bond by Molybdenum Complexes: Controlling the Dynamics of Exchange Between Proton and Hydride

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shaoguang; Appel, Aaron M.; Bullock, R. Morris

    2017-05-18

    Controlling the heterolytic cleavage of the H-H bond of dihydrogen is critically important in catalytic hydrogenations and in the catalytic oxidation of H2. We show how the rate of reversible heterolytic cleavage of H2 can be controlled over nearly four orders of magnitude at 25 °C, from 2.1 × 103 s-1 to ≥107 s-1. Bifunctional Mo complexes, [CpMo(CO)(κ3-P2N2)]+ (P2N2 = 1,5-diaza-3,7-diphosphacyclooctane with alkyl/aryl groups on N and P), have been developed for heterolytic cleavage of H2 into a proton and a hydride, akin to Frustrated Lewis Pairs. The H-H bond cleavage is enabled by the basic amine in the second coordination sphere. The products of heterolytic cleavage of H2, Mo hydride complexes bearing protonated amines, [CpMo(H)(CO)(P2N2H)]+, were characterized by spectroscopic studies and by X-ray crystallography. Variable temperature 1H, 15N and 2-D 1H-1H ROESY NMR spectra indicated rapid exchange of the proton and hydride. The exchange rates are in the order [CpMo(H)(CO)(PPh2NPh2H)]+ > [CpMo(H)(CO)(PtBu2NPh2H)]+ > [CpMo(H)(CO)(PPh2NBn2H)]+ > [CpMo(H)(CO)(PtBu2NBn2H)]+ > [CpMo(H)(CO)(PtBu2NtBu2H)]+. The pKa values determined in acetonitrile range from 9.3 to 17.7, and show a linear correlation with the logarithm of the exchange rates. Thus the exchange dynamics are controlled through the relative acidity of the [CpMo(H)(CO)(P2N2H)]+ and [CpMo(H2)(CO)(P2N2)]+ isomers, providing a design principle for controlling heterolytic cleavage of H2.

  11. Quantification of 16S rRNAs in complex bacterial communities by multiple competitive reverse transcription-PCR in temperature gradient gel electrophoresis fingerprints.

    Science.gov (United States)

    Felske, A; Akkermans, A D; De Vos, W M

    1998-11-01

    A novel approach was developed to quantify rRNA sequences in complex bacterial communities. The main bacterial 16S rRNAs in Drentse A grassland soils (The Netherlands) were amplified by reverse transcription (RT)-PCR with bacterium-specific primers and were separated by temperature gradient gel electrophoresis (TGGE). The primer pair used (primers U968-GC and L1401) was found to amplify with the same efficiency 16S rRNAs from bacterial cultures containing different taxa and cloned 16S ribosomal DNA amplicons from uncultured soil bacteria. The sequence-specific efficiency of amplification was determined by monitoring the amplification kinetics by kinetic PCR. The primer-specific amplification efficiency was assessed by competitive PCR and RT-PCR, and identical input amounts of different 16S rRNAs resulted in identical amplicon yields. The sequence-specific detection system used for competitive amplifications was TGGE, which also has been found to be suitable for simultaneous quantification of more than one sequence. We demonstrate that this approach can be applied to TGGE fingerprints of soil bacteria to estimate the ratios of the bacterial 16S rRNAs.

  12. Amine-free reversible hydrogen storage in formate salts catalyzed by ruthenium pincer complex without pH control or solvent change.

    Science.gov (United States)

    Kothandaraman, Jotheeswari; Czaun, Miklos; Goeppert, Alain; Haiges, Ralf; Jones, John-Paul; May, Robert B; Prakash, G K Surya; Olah, George A

    2015-04-24

    Due to the intermittent nature of most renewable energy sources, such as solar and wind, energy storage is increasingly required. Since electricity is difficult to store, hydrogen obtained by electrochemical water splitting has been proposed as an energy carrier. However, the handling and transportation of hydrogen in large quantities is in itself a challenge. We therefore present here a method for hydrogen storage based on a CO2 (HCO3 (-) )/H2 and formate equilibrium. This amine-free and efficient reversible system (>90 % yield in both directions) is catalyzed by well-defined and commercially available Ru pincer complexes. The formate dehydrogenation was triggered by simple pressure swing without requiring external pH control or the change of either the solvent or the catalyst. Up to six hydrogenation-dehydrogenation cycles were performed and the catalyst performance remained steady with high selectivity (CO free H2 /CO2 mixture was produced). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Fluorographene as a Mass Spectrometry Probe for High-Throughput Identification and Screening of Emerging Chemical Contaminants in Complex Samples.

    Science.gov (United States)

    Huang, Xiu; Liu, Qian; Huang, Xiaoyu; Nie, Zhou; Ruan, Ting; Du, Yuguo; Jiang, Guibin

    2017-01-17

    Mass spectrometry techniques for high-throughput analysis of complex samples are of profound importance in many areas such as food safety, omics studies, and environmental health science. Here we report the use of fluorographene (FG) as a new mass spectrometry probe for high-throughput identification and screening of emerging chemical contaminants in complex samples. FG was facilely synthesized by one-step exfoliation of fluorographite. With FG as a matrix or probe in matrix-assisted or surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (MALDI- or SELDI-TOF MS), higher sensitivity (detection limits at ppt or subppt levels), and better reproducibility were achieved than with other graphene-based materials due to the unique chemical structure and self-assembly properties of FG. The method was validated with different types of real complex samples. By using FG as a SELDI probe, we could easily detect trace amount of bisphenol S in paper products and high-fat canned food samples. Furthermore, we have successfully identified and screened as many as 28 quaternary ammonium halides in sewage sludge samples collected from municipal wastewater treatment plants. These results demonstrate that FG probe is a powerful tool for high-throughput analysis of complex samples by MS.

  14. Effect of different complexing agents on the properties of chemical-bath-deposited ZnS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jun; Wei, Aixiang, E-mail: weiax@gdut.edu.cn; Zhao, Yu

    2014-03-05

    Highlights: • To fabricate high quality ZnS films need to promote the ion-by-ion process and restrain cluster-by-cluster process. • The complexation ability of tri-sodium citrate is stronger than that of hydrazine hydrate. • The nucleation density of nuclei determine the performance of ZnS thin films. -- Abstract: Zinc sulfide (ZnS) thin films were deposited on glass substrates using the chemical bath deposition (CBD) technique. The effects of different complexing agents (tri-sodium citrate, hydrazine hydrate) and their concentrations on the structure, composition, morphology, optical properties and growth mechanism of ZnS thin films were investigated. The results indicated that the chemical-bath-deposited ZnS thin films exhibit poor crystallinity and a high Zn/S atomic ratio with an average transmittance of 75% in the range of visible light. The ZnS thin films prepared using hydrazine hydrate as the complexing agent present a more compact surface, a smaller average particle size, and a sharper absorption edge at 300–340 nm compared with those prepared using tri-sodium citrate. Based on our experimental observations and analysis, we conclude that the predominant growth mechanism of ZnS thin films is an ion-by-ion process. The nucleation density of Zn(OH){sub 2} nuclei on the substrate in the initial stage produces the different morphologies and properties of the ZnS thin films prepared using the two complexing agents.

  15. From simple to complex and backwards. Chemical reactions under very high pressure

    International Nuclear Information System (INIS)

    Bini, Roberto; Ceppatelli, Matteo; Citroni, Margherita; Schettino, Vincenzo

    2012-01-01

    Highlights: ► High pressure reactivity of several molecular systems. ► Reaction kinetics and dynamics in high density conditions. ► Key role of optical pumping and electronic excitation. ► Perspectives for the synthesis of hydrogen. - Abstract: High pressure chemical reactions of molecular systems are discussed considering the various factors that can affect the reactivity. These include steric hindrance and geometrical constraints in the confined environment of crystals at high pressure, changes of the free energy landscape with pressure, photoactivation by two-photon absorption, local and collective effects. A classification of the chemical reactions at high pressure is attempted on the basis of the prevailing factors.

  16. Chiral diamine-silver(I)-alkene complexes: a quantum chemical and NMR study

    DEFF Research Database (Denmark)

    Kieken, Elsa; Wiest, Olaf; Helquist, Paul

    2005-01-01

    explored by DFT methods. By successive substitution of the computational model complexes, it has been possible to elucidate the role of each amine substituent in achieving successful discrimination of alkenes. The conformational space has been fully explored using small model systems, allowing an unbiased......The ability of chiral diamine silver complexes to bind chiral and prochiral alkenes has been analyzed in detail. The stereoselectivity in binding of alkenes to a chiral ethanediamine silver complex has been investigated by NMR. The low-energy conformations of several small model complexes have been...... calculation of stereoselectivities that match well the experimental results. For a chiral allylic alcohol substrate, the correct stereoselectivity was obtained only when the structures were optimized with a continuum representation of the solvent. The discrepancy between gas phase and solution data is found...

  17. Searching for new thermoelectrics in chemically and structurally complex bismuth chalcogenides

    Energy Technology Data Exchange (ETDEWEB)

    Chung, D Y; Hogan, T; Schindler, J; Iordanidis, L; Brazis, P; Kannewurf, C R; Chen, B; Uher, C; Kanatzidis, M G

    1997-07-01

    A solid state chemistry synthetic approach towards identifying new materials with potentially superior thermoelectric properties is presented. Materials with complex compositions and structures also have complex electronic structures which may give rise to high thermoelectric powers and at the same time possess low thermal conductivities. The structures and thermoelectric properties of several new promising compounds with K-Bi-Se, K-Bi-S, Ba-Bi-Te, Cs-Bi-Te, and Rb-bi-Te are reported.

  18. CHEMICAL CONTAMINATION AND TOXICITY ASSOCIATED WITH A COASTAL GOLF COURSE COMPLEX

    Science.gov (United States)

    The increasing density of golf courses represents a potential source of contamination to nearby coastal areas, the chemical and biological magnitude of which is almost unknown. The objective of this study was to compare the concentrations of contaminants and toxicities of sedime...

  19. SEDIMENT CHEMICAL CONTAMINATION AND TOXICITY ASSOCIATED WITH A COASTAL GOLF COURSE COMPLEX.

    Science.gov (United States)

    The increasing density of golf courses represents a potential source of sediment contamination to nearby coastal areas, the chemical and biological magnitude of which is almost unknown. The objective of this study was to determine the concentrations of contaminants and toxicities...

  20. Evolved stars as complex chemical laboratories - the quest for gaseous chemistry

    Science.gov (United States)

    Katrien Els Decin, Leen

    2015-08-01

    At the end of their life, most stars lose a large fraction of their mass through a stellar wind. The stellar winds of evolved (super)giant stars are the dominant suppliers for the pristine building blocks of the interstellar medium (ISM). Crucial to the understanding of the chemical life cycle of the ISM is hence a profound insight in the chemical and physical structure governing these stellar winds.These winds are really unique chemical laboratories in which currently more than 70 different molecules and 15 different dust species are detected. Several chemical processes such as neutral-neutral and ion-molecule gas-phase reactions, dust nucleation and growth, and photo-processes determine the chemical content of these winds. However, gas-phase and dust-nucleation chemistry for astronomical environments still faces many challenges. One should realize that only ˜15% of the rate coefficients for gas-phase reactions considered to occur in (inter/circum)stellar regions at temperatures (T) below 300K have been subject to direct laboratory determinations and that the temperature dependence of the rate constants is often not known; only ˜2% have rate constants at Tgrant, we are now in the position to solve some riddles involved in understanding the gas-phase chemistry in evolved stars. In this presentation, I will demonstrate the need for accurate temperature-dependent gas-phase reaction rate constants and will present our new laboratory equipment built to measure the rate constants for species key in stellar wind chemistry. Specifically, we aim to obtain the rate constants of reactions involving silicon- and sulphur bearing species and HCCO for 30

  1. Preparation and chemical studies on Tc(III) complexes containing polyaminocarboxylic acids

    International Nuclear Information System (INIS)

    Gonzalez, R.; Kremer, C.; Chiozzone, R.; Torres, J.; Rivero, M.; Kremer, E.; Leon, A.

    1998-01-01

    Tc(III)-edta (edta = ethylenediaminetetraacetate), Tc(III)-dtpa (dtpa = diethylenetriaminepentaacetate) and Tc(III)-mebrofenin (mebrofenin = 3-bromo-2,4,6-trimethylacetanilideiminodiacetate) complexes were prepared by ligand substitution reactions on hexakis(thiourea)technetium(III) cation with the polycarboxylates. By a combination of different techniques (UV-Vis, IR and 1 H-NMR spectroscopy, Tc elemental analyses and cerimetric titrations) it was concluded that 1:1 complexes are formed with edta and dtpa while mebrofening adopts a 2:1 (ligand to metal) stoichiometry. Complementary, molecular mechanics calculations were performed to analyze the spatial arrangement of the molecules. The stability of the Tc(III) complexes was studied in aqueous solution by paper chromatography, paper electrophoresis and cyclic voltammetry. The chelates are rather stable, in particular when compared with the precursor. (orig.)

  2. Quantum chemical and thermodynamic calculations of fulvic and humic copper complexes in reactions of malachite and azurite formation

    International Nuclear Information System (INIS)

    Fomin, Vitaliy N.; Gogol, Daniil B.; Rozhkovoy, Ivan E.; Ponomarev, Dmitriy L.

    2017-01-01

    This article provides a thermodynamic evaluation of the reactions of humic and fulvic acids in the process of malachite and azurite mineralogenesis. Semi-empirical methods AM/1, MNDO, PM3, PM5, PM6 and PM7 were used to compute the heat of formation, enthalpy and entropy for thermodynamic calculations of the reactions performed on the basis of Hess's law. It is shown that methods PM6 and PM7 in the MOPAC software package provide good compliance with experimental and calculated heats of formation for copper complexes and alkaline earth metal complexes with organic acids. It is found that the malachite and azurite formation processes involving humus complexing substances are thermodynamically possible. - Highlights: • Copper and alkali-earth metal complexes with humic and fulvic acids are considered. • Quantum chemical calculation of thermodynamics for the structures was performed. • Semi-empirical methods PM6 and PM7 provide best correlation for the properties. • Parameters of basic copper carbonate formation reactions were obtained by Hess's law. • Processes of malachite and azurite formation from humus complexes are possible.

  3. K70Q adds high-level tenofovir resistance to "Q151M complex" HIV reverse transcriptase through the enhanced discrimination mechanism.

    Directory of Open Access Journals (Sweden)

    Atsuko Hachiya

    2011-01-01

    Full Text Available HIV-1 carrying the "Q151M complex" reverse transcriptase (RT mutations (A62V/V75I/F77L/F116Y/Q151M, or Q151Mc is resistant to many FDA-approved nucleoside RT inhibitors (NRTIs, but has been considered susceptible to tenofovir disoproxil fumarate (TFV-DF or TDF. We have isolated from a TFV-DF-treated HIV patient a Q151Mc-containing clinical isolate with high phenotypic resistance to TFV-DF. Analysis of the genotypic and phenotypic testing over the course of this patient's therapy lead us to hypothesize that TFV-DF resistance emerged upon appearance of the previously unreported K70Q mutation in the Q151Mc background. Virological analysis showed that HIV with only K70Q was not significantly resistant to TFV-DF. However, addition of K70Q to the Q151Mc background significantly enhanced resistance to several approved NRTIs, and also resulted in high-level (10-fold resistance to TFV-DF. Biochemical experiments established that the increased resistance to tenofovir is not the result of enhanced excision, as K70Q/Q151Mc RT exhibited diminished, rather than enhanced ATP-based primer unblocking activity. Pre-steady state kinetic analysis of the recombinant enzymes demonstrated that addition of the K70Q mutation selectively decreases the binding of tenofovir-diphosphate (TFV-DP, resulting in reduced incorporation of TFV into the nascent DNA chain. Molecular dynamics simulations suggest that changes in the hydrogen bonding pattern in the polymerase active site of K70Q/Q151Mc RT may contribute to the observed changes in binding and incorporation of TFV-DP. The novel pattern of TFV-resistance may help adjust therapeutic strategies for NRTI-experienced patients with multi-drug resistant (MDR mutations.

  4. Characterization of milk proteins-lutein complexes and the impact on lutein chemical stability.

    Science.gov (United States)

    Yi, Jiang; Fan, Yuting; Yokoyama, Wallace; Zhang, Yuzhu; Zhao, Liqing

    2016-06-01

    In this study, the interaction of WPI (whey protein isolate) and SC (sodium caseinate) with hydrophobic lutein was investigated through UV-vis spectroscopy and circular dichroism (CD) as well as fluorescence. The effects on lutein's chemical stability were also examined. The decrease of turbidity of lutein suggested that lutein's aqueous solubility was improved after binding with milk proteins. CD analysis indicated lutein had little impact on the secondary structures of both proteins. Different preparation methods have significant impacts on the binding constant. Fluorescence results indicated that WPI and SC interact with lutein by hydrophobic contacts. Milk proteins have protective effects on lutein against oxidation and decomposition, and SC showed better capability in protecting lutein from oxidation than WPI during 16 days storage. The lutein's chemical stability was increased with increasing of proteins concentration. The results indicated that milk proteins may act as effective carriers for lipophilic nutraceuticals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Simple growth patterns can create complex trajectories for the ontogeny of constitutive chemical defences in seaweeds.

    Directory of Open Access Journals (Sweden)

    Nicholas A Paul

    Full Text Available All of the theory and most of the data on the ecology and evolution of chemical defences derive from terrestrial plants, which have considerable capacity for internal movement of resources. In contrast, most macroalgae--seaweeds--have no or very limited capacity for resource translocation, meaning that trade-offs between growth and defence, for example, should be localised rather than systemic. This may change the predictions of chemical defence theories for seaweeds. We developed a model that mimicked the simple growth pattern of the red seaweed Asparagopsis armata which is composed of repeating clusters of somatic cells and cells which contain deterrent secondary chemicals (gland cells. To do this we created a distinct growth curve for the somatic cells and another for the gland cells using empirical data. The somatic growth function was linked to the growth function for defence via differential equations modelling, which effectively generated a trade-off between growth and defence as these neighbouring cells develop. By treating growth and defence as separate functions we were also able to model a trade-off in growth of 2-3% under most circumstances. However, we found contrasting evidence for this trade-off in the empirical relationships between growth and defence, depending on the light level under which the alga was cultured. After developing a model that incorporated both branching and cell division rates, we formally demonstrated that positive correlations between growth and defence are predicted in many circumstances and also that allocation costs, if they exist, will be constrained by the intrinsic growth patterns of the seaweed. Growth patterns could therefore explain contrasting evidence for cost of constitutive chemical defence in many studies, highlighting the need to consider the fundamental biology and ontogeny of organisms when assessing the allocation theories for defence.

  6. Integrated centralized utility services to a chemical complex on Jurong Island, Singapore.

    Science.gov (United States)

    Yan, Y G; Wong, P C Y; Tan, C G; Tang, K F

    2003-01-01

    SUT pioneered centralized utility services for the chemical industry on Jurong Island, which are cost-effective due to economies of scale, reliable due to inter-connection of satellite operations, and customer tailored for special requirements. The utility services range from the supply of steam and water, wastewater treatment, incineration, terminalling, service corridor to fire fighting. Among the services, water management achieves the complete cycle from wastewater treatment to effluent recycling.

  7. Endocrine-Disrupting Chemicals and Oil and Natural Gas Operations: Potential Environmental Contamination and Recommendations to Assess Complex Environmental Mixtures.

    Science.gov (United States)

    Kassotis, Christopher D; Tillitt, Donald E; Lin, Chung-Ho; McElroy, Jane A; Nagel, Susan C

    2016-03-01

    Hydraulic fracturing technologies, developed over the last 65 years, have only recently been combined with horizontal drilling to unlock oil and gas reserves previously deemed inaccessible. Although these technologies have dramatically increased domestic oil and natural gas production, they have also raised concerns for the potential contamination of local water supplies with the approximately 1,000 chemicals that are used throughout the process, including many known or suspected endocrine-disrupting chemicals. We discuss the need for an endocrine component to health assessments for drilling-dense regions in the context of hormonal and antihormonal activities for chemicals used. We discuss the literature on a) surface and groundwater contamination by oil and gas extraction operations, and b) potential human exposure, particularly in the context of the total hormonal and antihormonal activities present in surface and groundwater from natural and anthropogenic sources; we also discuss initial analytical results and critical knowledge gaps. In light of the potential for environmental release of oil and gas chemicals that can disrupt hormone receptor systems, we recommend methods for assessing complex hormonally active environmental mixtures. We describe a need for an endocrine-centric component for overall health assessments and provide information supporting the idea that using such a component will help explain reported adverse health trends as well as help develop recommendations for environmental impact assessments and monitoring programs.

  8. Endocrine-disrupting chemicals and oil and natural gas operations: Potential environmental contamination and recommendations to assess complex environmental mixtures

    Science.gov (United States)

    Kassotis, Christopher D.; Tillitt, Donald E.; Lin, Chung-Ho; McElroy, Jane A.; Nagel, Susan C.

    2016-01-01

    Background: Hydraulic fracturing technologies, developed over the last 65 years, have only recently been combined with horizontal drilling to unlock oil and gas reserves previously deemed inaccessible. While these technologies have dramatically increased domestic oil and natural gas production, they have also raised concerns for the potential contamination of local water supplies with the approximately 1,000 chemicals used throughout the process, including many known or suspected endocrine-disrupting chemicals.Objectives: We discuss the need for an endocrine component to health assessments for drilling-dense regions in the context of hormonal and anti-hormonal activities for chemicals used.Methods: We discuss the literature on 1) surface and ground water contamination by oil and gas extraction operations, and 2) potential human exposure, particularly in context of the total hormonal and anti-hormonal activities present in surface and ground water from natural and anthropogenic sources, with initial analytical results and critical knowledge gaps discussed.Discussion: In light of the potential for environmental release of oil and gas chemicals that can disrupt hormone receptor systems, we recommend methods for assessing complex hormonally active environmental mixtures.Conclusions: We describe a need for an endocrine-centric component for overall health assessments and provide supporting information that using this may help explain reported adverse health trends as well as help develop recommendations for environmental impact assessments and monitoring programs.

  9. Chemical and biological evaluation of Sm-153 and Ho-166 complexes with tetraethylester of DOTP ( DOTPOEt )

    Czech Academy of Sciences Publication Activity Database

    Forsterová, Michaela; Margues, M. M.; Jandurová, Z.; Gano, L.; Hermann, P.; Melichar, František

    2007-01-01

    Roč. 50, č. 1 (2007), s. 273-273 ISSN 0362-4803 R&D Projects: GA AV ČR 1QS100480501 Institutional research plan: CEZ:AV0Z10480505 Keywords : Phosphonate Complexes Subject RIV: FR - Pharmacology ; Medidal Chemistry

  10. Study of chemical bonding in the interhalogen complexes based on density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Poleshchuk, O. Kh., E-mail: poleshch@tspu.edu.ru [National Research Tomsk Polytechnic University (Russian Federation); Fateev, A. V.; Yarkova, A. G. [Tomsk State Pedagogical University (Russian Federation); Ermakhanov, M. N.; Saidakhmetov, P. A. [M. Auezov South Kazakhstan State University (Kazakhstan)

    2016-12-15

    The density functional theory analysis was used for a number XYL complexes (XY is a dihalogen molecule and L is a Lewis base), formed between molecules I{sub 2}, ICl, IBr and pyridine. The calculated geometrical parameters, IR spectra and nuclear quadrupole interaction constants of iodine are consistent with the data of microwave spectroscopy and nuclear quadrupole resonance. The good correlation between the experimental and calculated binding energies of the inner electrons of iodine, chlorine and nitrogen atoms were found with the calculation using both Gaussian and Slater functions. The comparison of experimental and calculated changes in the electron density on the atoms upon complex formation suggested the choice of scheme for calculating the effective charge on the atoms, which allow us to interpret the experimental spectra. It is shown that the use of both calculated schemes allows us to predict the enthalpy of complex formation in close agreement with the experimental values. The energy analysis shows that in the complexes the electrostatic binding energy dominates that of covalent binding.

  11. Enzymatic reactions in reversed micelles

    NARCIS (Netherlands)

    Hilhorst, M.H.

    1984-01-01

    It has been recognised that enzymes in reversed micelles have potential for application in chemical synthesis. Before these expectations will be realised many problems must be overcome. This thesis deals with some of them.
    In Chapter 1 the present knowledge about reversed micelles and

  12. Chemical characterization of organic aerosol above a mid-latitude forest reveals a complex mixture of highly-functionalized chemical species and diverse structural features with temporal variability

    Science.gov (United States)

    Gentner, D. R.; Ditto, J.; Barnes, E.; Khare, P.

    2017-12-01

    Highly-functionalized organic compounds are known to be a major component of the complex mixture of the particle-phase compounds that comprise organic aerosol, yet little is known about the identity of many of these compounds, and their formation pathways and roles in atmospheric processes are poorly understood. We present results from the comprehensive chemical speciation of PM10 organic aerosols collected in July 2016 at the remote mid-latitude forest field site during PROPHET. Samples were analyzed via liquid and gas chromatography coupled with a quadrupole time-of-flight tandem mass spectrometry (MS×MS) following electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). 8 hr samples were collected during day- and night-time sampling periods rather than more typical 24-hour samples. This analysis of the organic aerosol yielded over 12,000 unique compounds for which we have high accuracy molecular masses, formulas, and additional information on structural features using MS×MS. O:C ratios were 0.3 on average, yet the top 10% of compounds ranged 0.7-2.3. 70% and 69% of day- and night-time samples were nitrogen-containing, whereas 26% and 24% contained sulfur, respectively. Within these broader molecular categories, we observed a wide variety of molecular features that reveal a diversity of functional groups and moieties. In this presentation, we present the results of our speciation, temporal variability, connections to air parcel back trajectories and other bulk properties, and potential formation pathways.

  13. Occupational risks for health of the workers of the chemical complex

    Directory of Open Access Journals (Sweden)

    E.T. Valeyeva

    2016-09-01

    Full Text Available The article summarizes the materials of long-term studies to assess the working conditions, state of health in workers of the chemical industry - mainly manufacturers of ethylbenzene, styrene, olefin oxides, rocket fuel. It was found that the most adverse working conditions are typical for the production of heptyl, rubber and fiberglass. The causal relationships of working conditions in the form of an increased incidence of early (pre-clinical stages of occupational diseases, as well as major chronic non-communicable diseases, are identified. It is shown that depending on the tropism, mechanism of action and intensity of the chemical factor a clear staging of the development of pathological changes in the body is recorded. A very high degree of professional conditionality of early toxic hepatitis stages (biliary dyskinesia in a heptyl production operator was determined, as well as initial manifestations of autonomic-sensory polyneuropathy in hands of the workers splicing rubber products, specific changes of the hand skin in glass production operators. Production-related diseases with a high degree of conditionality in certain categories of workers include diseases of the musculoskeletal system; hypertension had an average degree of conditionality. During in-depth medical examination of 2411 workers it was found that the largest number of healthy individuals were identified in the bulk manufacture of ethylbenzene – styrene (54.7 %, and olefin oxide (35,0 % of the number of inspected workers, the least number (12 % – in the manufacture of rubber products. The remaining workers demonstrated the pathology of various organs and systems. Based on the results of risk assessment and professional damage to the workers’ health the chemical productions are ranked according to their degree of danger, a system of preventive measures and risk management principles has been developed. The programme implementation resulted in the positive effect of more

  14. Synthesis, physico-chemical properties and complexing abilities of new amphiphilic ligands from D-galacturonic acid.

    Science.gov (United States)

    Allam, Anas; Behr, Jean-Bernard; Dupont, Laurent; Nardello-Rataj, Véronique; Plantier-Royon, Richard

    2010-04-19

    This paper describes a convenient and efficient synthesis of new complexing surfactants from d-galacturonic acid and n-octanol as renewable raw materials in a two-step sequence. In the first step, simultaneous O-glycosidation-esterification under Fischer conditions was achieved. The anomeric ratio of the products was studied based on the main experimental parameters and the activation mode (thermal or microwave). In the second step, aminolysis of the n-octyl ester was achieved with various functionalized primary amines under standard thermal or microwave activation. The physico-chemical properties of these new amphiphilic ligands were measured and these compounds were found to exhibit interesting surface properties. Complexing abilities of one uronamide ligand functionalized with a pyridine moiety toward Cu(II) ions was investigated in solution by EPR titrations. A solid compound was also synthesized and characterized, its relative structure was deduced from spectroscopic data. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  15. ELECTROREDUCTION MECHANISM OF Ni(DMG)-2 COMPLEX STUDIED WITH QUANTUM CHEMICAL METHOD

    Institute of Scientific and Technical Information of China (English)

    倪亚明; 任镜清; 黎健; 王德民; 梁伟根; 朱芝仙; 高小霞

    1990-01-01

    The electronic structures of the species Ni(DMG)2, (Ni(DMG)2)- and (Ni(DMG)2)2- have been studied by INDO quantum chemical method. The results have clearly shown that in the first stage of the electroreduction of Ni(DMG)2, one electron interacts with the d orbitals on the nickel atom, while in the further stage the second electron interacts with the p orbitals on the nitrogen atoms. It conforms with our electrochemical experimental studies which showed that not only Ni(Ⅱ) is reduced but also DMG is catalytically reduced during the reduction of Ni(DMG)2.

  16. Chemical proprieties of the iron-quinone complex in mutated reaction centers of Rb. sphaeroides

    International Nuclear Information System (INIS)

    Hałas, Agnieszka; Derrien, Valerie; Sebban, Pierre; Matlak, Krzysztof; Korecki, Józef; Kruk, Jerzy; Burda, Kvĕtoslava

    2012-01-01

    We investigated type II bacterial photosynthetic reaction centers, which contain a quinone - iron complex (Q A -Fe-Q B ) on their acceptor side. Under physiological conditions it was observed mainly in a reduced high spin state but its low spin ferrous states were also observed. Therefore, it was suggested that it might regulate the dynamical properties of the iron–quinone complex and the protonation and deprotonation events in its neighbourhood. In order to get insight into the molecular mechanism of the NHFe low spin state formation, we preformed Mössbauer studies of a wild type of Rb. sphaeroides and its two mutated forms. Our Mössbauer measurements show that the hydrophobicity of the Q A binding site can be crucial for stabilization of the high spin ferrous state of NHFe.

  17. Chemical Imaging and Dynamical Studies of Reactivity and Emergent Behavior in Complex Interfacial Systems. Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Sibener, Steven J. [Univ. of Chicago, IL (United States). James Franck Inst. and Dept. of Chemistry

    2014-03-11

    This research program explored the efficacy of using molecular-level manipulation, imaging and scanning tunneling spectroscopy in conjunction with supersonic molecular beam gas-surface scattering to significantly enhance our understanding of chemical processes occurring on well-characterized interfaces. One program focus was on the spatially-resolved emergent behavior of complex reaction systems as a function of the local geometry and density of adsorbate-substrate systems under reaction conditions. Another focus was on elucidating the emergent electronic and related reactivity characteristics of intentionally constructed single and multicomponent atom- and nanoparticle-based materials. We also examined emergent chirality and self-organization in adsorbed molecular systems where collective interactions between adsorbates and the supporting interface lead to spatial symmetry breaking. In many of these studies we combined the advantages of scanning tunneling (STM) and atomic force (AFM) imaging, scanning tunneling local electronic spectroscopy (STS), and reactive supersonic molecular beams to elucidate precise details of interfacial reactivity that had not been observed by more traditional surface science methods. Using these methods, it was possible to examine, for example, the differential reactivity of molecules adsorbed at different bonding sites in conjunction with how reactivity is modified by the local configuration of nearby adsorbates. At the core of this effort was the goal of significantly extending our understanding of interfacial atomic-scale interactions to create, with intent, molecular assemblies and materials with advanced chemical and physical properties. This ambitious program addressed several key topics in DOE Grand Challenge Science, including emergent chemical and physical properties in condensed phase systems, novel uses of chemical imaging, and the development of advanced reactivity concepts in combustion and catalysis including carbon

  18. HM{sup +}–RG complexes (M = group 2 metal; RG = rare gas): Physical vs. chemical interactions

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Joe P.; Dodson, Hannah; Wright, Timothy G., E-mail: Tim.Wright@nottingham.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Breckenridge, W. H. [Department of Chemistry, University of Utah, Salt Lake City, Utah 84112 (United States)

    2015-04-21

    Previous work on the HM{sup +}–He complexes (M = Be–Ra) has been extended to the cases of the heavier rare gas atoms, HM{sup +}–RG (RG = Ne–Rn). Optimized geometries and harmonic vibrational frequencies have been calculated using MP2 theory and quadruple-ζ quality basis sets. Dissociation energies for the loss of the rare gas atom have been calculated at these optimized geometries using coupled cluster with single and double excitations and perturbative triples, CCSD(T)theory, extrapolating interaction energies to the basis set limit. Comparisons are made between the present data and the previously obtained helium results, as well as to those of the bare HM{sup +} molecules; furthermore, comparisons are made to the related M{sup +}–RG and M{sup 2+}–RG complexes. Partial atomic charge analyses have also been undertaken, and these used to test a simple charge-induced dipole model. Molecular orbital diagrams are presented together with contour plots of the natural orbitals from the quadratic configuration with single and double excitations (QCISD) density. The conclusion is that the majority of these complexes are physically bound, with very little sharing of electron density; however, for M = Be, and to a lesser extent M = Mg, some evidence for chemical effects is seen in HM{sup +}–RG complexes involving RG atoms with the higher atomic numbers.

  19. Liquid Membranes as a Tool for Chemical Speciation of Metals in Natural Waters: Organic and Inorganic Complexes of Nickel.

    Science.gov (United States)

    Vergel, Cristina; Mendiguchía, Carolina; Moreno, Carlos

    2018-04-15

    The different species of nickel present in natural waters exhibit different transport behaviour through bulk liquid membranes (BLMs). This fact has been used to design and optimise a separation/pre-concentration system applicable to separate labile and non-labile nickel fractions. A hydrazone derivative-1,2-cyclohexanedione bis-benzoyl-hydrazone (1,2-CHBBH) dissolved in toluene/dimethyl formamide (2% DMF)-was used as a chemical carrier of nickel species, from an aqueous source solution (sample) to a receiving acidic solution. Both chemical and hydrodynamic conditions controlling the transport system were studied and optimised. Under optimum conditions, variations in the transport of nickel ions as a function of organic (humic acids) and inorganic (chloride ions) ligands were studied. Relationships between the permeability coefficient ( P ) or recovery efficiency (%R) and the concentrations of ligands and nickel species were analysed using Winhumic V software. A negative correlation between P and the concentration of organic nickel complexes was found, suggesting that only labile nickel species are transported through the liquid membrane, with non-labile complexes remaining in the water sample; allowing for their separation and subsequent quantification in natural waters.

  20. Effect of complex polyphenols and tannins from red wine (WCPT) on chemically induced oxidative DNA damage in the rat.

    Science.gov (United States)

    Casalini, C; Lodovici, M; Briani, C; Paganelli, G; Remy, S; Cheynier, V; Dolara, P

    1999-08-01

    Flavonoids are polyphenolic antioxidants occurring in vegetables and fruits as well as beverages such as tea and wine which have been thought to influence oxidative damage. We wanted to verify whether a complex mixture of wine tannins (wine complex polyphenols and tannins, WCPT) prevent chemically-induced oxidative DNA damage in vivo. Oxidative DNA damage was evaluated by measuring the ratio of 8-hydroxy-2'-deoxyguanosine (80HdG)/ 2-deoxyguanosine (2dG) x 10(-6) in hydrolyzed DNA using HPLC coupled with electrochemical and UV detectors. We treated rats with WCPT (57 mg/kg p.o.) for 14 d, a dose 10-fold higher than what a moderate wine drinker would be exposed to. WCPT administration significantly reduced the ratio of 80HdG/2dG x 10(-6) in liver DNA obtained from rats treated with 2-nitropropane (2NP) relative to controls administered 2NP only (33. 3 +/- 2.5 vs. 44.9 +/- 3.2 x 10(-6) 2dG; micro +/- SE; p<0.05). On the contrary, pretreatment with WCPT for 10 d did not protect the colon mucosa from oxidative DNA damage induced by 1, 2-dimethylhydrazine (DMH). 2NP and DMH are hepatic and colon carcinogens, respectively, capable of inducing oxidative DNA damage. WCPT have protective action against some types of chemically-induced oxidative DNA damage in vivo.

  1. Liquid Membranes as a Tool for Chemical Speciation of Metals in Natural Waters: Organic and Inorganic Complexes of Nickel

    Directory of Open Access Journals (Sweden)

    Cristina Vergel

    2018-04-01

    Full Text Available The different species of nickel present in natural waters exhibit different transport behaviour through bulk liquid membranes (BLMs. This fact has been used to design and optimise a separation/pre-concentration system applicable to separate labile and non-labile nickel fractions. A hydrazone derivative—1,2-cyclohexanedione bis-benzoyl-hydrazone (1,2-CHBBH dissolved in toluene/dimethyl formamide (2% DMF—was used as a chemical carrier of nickel species, from an aqueous source solution (sample to a receiving acidic solution. Both chemical and hydrodynamic conditions controlling the transport system were studied and optimised. Under optimum conditions, variations in the transport of nickel ions as a function of organic (humic acids and inorganic (chloride ions ligands were studied. Relationships between the permeability coefficient (P or recovery efficiency (%R and the concentrations of ligands and nickel species were analysed using Winhumic V software. A negative correlation between P and the concentration of organic nickel complexes was found, suggesting that only labile nickel species are transported through the liquid membrane, with non-labile complexes remaining in the water sample; allowing for their separation and subsequent quantification in natural waters.

  2. Chemical states and electronic properties of the interface between aluminium and a photoluminescent conjugated copolymer containing europium complex

    International Nuclear Information System (INIS)

    Cai, Q.J.; Ling, Q.D.; Li, S.; Zhu, F.R.; Huang, Wei; Kang, E.T.; Neoh, K.G.

    2004-01-01

    The chemical states and electronic properties of the interface between thermally evaporated aluminium and a photoluminescent conjugated copolymer containing 9,9'-dihexylfluorene and europium complex-chelated benzoate units in the main chain (PF6-Eu(dbm) 2 phen) were studied in situ by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The changes in C 1s, Eu 3d, N 1s, and Al 2p core-level lineshapes with progressive deposition of aluminium atoms were carefully monitored. Aluminium was found to interact with the conjugated backbone of the copolymer to form the Al carbide, Al-O-C complex, and Al(III)-N chelate at the interface. In addition, the europium ions were reduced to the metallic state by the deposited aluminium atoms, which were oxidized and chelated by the 1,10-phenanthroline ligands (phen). The changes in chemical states at the interface suggest that the intramolecular energy transfer process in this copolymer had been affected. Moreover, aluminium also interacted with the bulk-adsorbed oxygen, which migrates to the surface in response to the deposition of aluminium atoms, to form a layer of metal oxides. On the other hand, the evolution of the UPS spectra suggests that the π-states of the conjugated system were affected and an unfavorable dipole layer was induced by the deposited aluminium atoms

  3. Physico-Chemical Properties and Phase Behavior of the Ionic Liquid-β-Cyclodextrin Complexes

    Directory of Open Access Journals (Sweden)

    Michał Wlazło

    2013-08-01

    Full Text Available The solubility of β-cyclodextrin (β-CD in ionic liquids (ILs and the activity coefficients at infinite dilution ( of more than 20 solutes (alkanes, aromatic hydrocarbons, alcohols were measured in four chosen ionic liquids, their mixtures with β-CD, and in the β-CD at high temperatures from 338 to 398 K using the inverse gas chromatography. The intermolecular interactions, inclusion complexes and the possible increasing of the solubility of β-CD in water using the IL are presented. The solubility of β-CD in ten chosen hydrophobic ILs at the temperature T = 423 K was detected. The solid-liquid phase diagrams (SLE of {IL (1 + β-CD (2} binary systems at the high mole fraction of the IL were measured for three systems (1-ethyl-3-methylimidazolium chloride, [EMIM][Cl], 1-ethyl-3-methylimidazolium bromide, [EMIM][Br]; and for 1-butyl-3-methylimidazolium chloride, [BMIM][Cl]. The eutectic points were determined at the high IL concentration for all binary systems. The intermolecular interaction and the possibility of inclusion complexes of the IL and/or solvents with β-CD were discussed. The infrared spectroscopy, IR was used for the description of the intermolecular interactions in the (β-CD + IL systems. It was shown via the activity coefficients at infinite dilution results that the inclusion complexes are dependent on the temperature. The addition of β-CD to the IL does not improve the selectivity of the separation of the aliphatics from aromatics.

  4. Chemical dissolution of spent fuel and cladding using complexed fluoride species

    International Nuclear Information System (INIS)

    Rance, P.J.W.; Freeman, G.A.; Mishin, V.; Issoupov, V.

    2001-01-01

    The dissolution of LWR fuel cladding using two fluoride ion donors, HBF 4 and K 2 ZrF 6 , in combination with nitric acid has been investigated as a potential reprocessing head-end process suitable for chemical decladding and fuel dissolution in a single process step. Maximum zirconium concentrations in the order of 0,75 to 1 molar have been achieved and dissolution found to continue to low F:Zr ratios albeit at ever decreasing rates. Dissolution rates of un-oxidised zirconium based fuel claddings are fast, whereas oxidised materials exhibit an induction period prior to dissolution. Data is presented relating to the rates of dissolution of cladding and UO 2 fuels under various conditions. (author)

  5. Effects of chemical complexity on the autoxidation mechanisms of endocyclic alkene ozonolysis products

    DEFF Research Database (Denmark)

    Rissanen, Matti P.; Kurtén, Theo; Sipilä, Mikko

    2015-01-01

    (NO3-) based ionization scheme. The experiments were performed in borosilicate glass flow tube reactors at room temperature (T = 293 ± 3 K) and at ambient pressure. An ensemble of oxidized monomer and dimer products was detected, with elemental compositions obtained from the high......Formation of highly oxidized, multifunctional products in the ozonolysis of three endocyclic alkenes, 1- methylcyclohexene, 4-methylcyclohexene, and α-pinene, was investigated using a chemical ionization atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometer with a nitrate ion......-resolution mass spectra. The monomer product distributions have O/C ratios from 0.8 to 1.6 and can be explained with an autocatalytic oxidation mechanism (=autoxidation) where the oxygen-centered peroxy radical (RO2) intermediates internally rearrange by intramolecular hydrogen shift reactions...

  6. pH-Dependent spin state population and 19F NMR chemical shift via remote ligand protonation in an iron(ii) complex.

    Science.gov (United States)

    Gaudette, Alexandra I; Thorarinsdottir, Agnes E; Harris, T David

    2017-11-30

    An Fe II complex that features a pH-dependent spin state population, by virtue of a variable ligand protonation state, is described. This behavior leads to a highly pH-dependent 19 F NMR chemical shift with a sensitivity of 13.9(5) ppm per pH unit at 37 °C, thereby demonstrating the potential utility of the complex as a 19 F chemical shift-based pH sensor.

  7. Survey on bio-chemical complex harmonized with global environment. 3; Kankyo chowagata seibutsu kagaku konbinato ni kansuru chosa. 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    A survey was conducted of bio-chemical complex harmonized with the global environment for the purpose of constructing the material production process harmonized with the environment by the process fusion between biological conversion and chemical reaction. Palm oil was taken up as renewable raw material plant resource. The process utilizing bio-chemical reaction advances at normal temperature and pressure and is high in reaction specificity and selectivity. This is a recycling, circulation and environmental harmony type production technology which brings high yield, energy conservation, resource conservation, and low environmental loads. Waste water treatment and production of useful substances from sludge were thought as elementary technology. A possibility was studied of enzyme production by culturing solid waste, and the enzyme was applied to the hydrolysis process. The paper indicated trace components in the palm oil and the extraction method and proposed the production process of new derivatives for adding value to hydrolysate. A study was also made of the overall process flow which integrated these new processes and the material balance. The comprehensive evaluation of this new process was made from the aspect of the product structure, the market, construction cost, economical efficiency, and the environment. 133 refs., 65 figs., 56 tabs.

  8. Advantages of paramagnetic chemical exchange saturation transfer (CEST) complexes having slow to intermediate water exchange properties as responsive MRI agents.

    Science.gov (United States)

    Soesbe, Todd C; Wu, Yunkou; Dean Sherry, A

    2013-07-01

    Paramagnetic chemical exchange saturation transfer (PARACEST) complexes are exogenous contrast agents that have great potential to further extend the functional and molecular imaging capabilities of magnetic resonance. As a result of the presence of a central paramagnetic lanthanide ion (Ln(3+) ≠ La(3+) , Gd(3+) , Lu(3+) ) within the chelate, the resonance frequencies of exchangeable protons bound to the PARACEST agent are shifted far away from the bulk water frequency. This large chemical shift, combined with an extreme sensitivity to the chemical exchange rate, make PARACEST agents ideally suited for the reporting of significant biological metrics, such as temperature, pH and the presence of metabolites. In addition, the ability to turn PARACEST agents 'off' and 'on' using a frequency-selective saturation pulse gives them a distinct advantage over Gd(3+) -based contrast agents. A current challenge for PARACEST research is the translation of the promising in vitro results into in vivo systems. This short review article first describes the basic theory behind PARACEST contrast agents, their benefits over other contrast agents and their applications to MRI. It then describes some of the recent PARACEST research results: specifically, pH measurements using water molecule exchange rate modulation, T2 exchange contrast caused by water molecule exchange, the use of ultrashort TEs (TE < 10 µs) to overcome T2 exchange line broadening and the potential application of T2 exchange as a new contrast mechanism for MRI. Copyright © 2012 John Wiley & Sons, Ltd.

  9. The impact of the Almalyk Industrial Complex on soil chemical and biological properties

    International Nuclear Information System (INIS)

    Shukurov, Nosir; Pen-Mouratov, Stanislav; Steinberger, Yosef

    2005-01-01

    The effect of heavy metals on soil free-living nematodes, microbial biomass (C mic ) and basal respiration (BR) was studied along a 15 km downwind deposition gradient, originating at the Almalyk Industrial Complex. Soil samples from 0-10 and 10-20 cm layers were collected at 5 km intervals. A significant decrease in heavy metal deposition was found going from the source in the downwind direction and with depth. The soil microbial biomass, basal respiration and derived microbial indices for soil samples from the Almalyk industrial area were analysed. The lowest soil microbial biomass and total number of free-living nematodes were found in soil samples near the industrial complex, with a high heavy metal and weak total organic carbon (C org ) content. The highest C mic was found in the soil samples collected 15 km from the pollution source. BR displayed similar results. The derived indices, metabolic quotient (qCO 2 ) and microbial ratio (C mic /C org ), revealed significant differences with distance, confirming environmental stress in the first and second locations. The present study elucidates the importance of soil nematode and microbial populations as suitable tools for bio-monitoring the effect of heavy metals on soil systems. - Soil nematodes and microbes are suitable biomonitors for metals in soils

  10. Combined use of meio- and macrobenthic indices to assess complex chemical impacts on a stream ecosystem

    Science.gov (United States)

    McKnight, Ursula S.; Sonne, Anne T.; Rasmussen, Jes J.; Traunspurger, Walter; Höss, Sebastian; Bjerg, Poul L.

    2016-04-01

    Ecosystem dynamics (e.g. temperature, inorganic nutrients) and properties (e.g. resilience, robustness), and ecological functions and services depend on the structure and diversity of biological communities, and the fluxes of energy and materials occurring within and across abiotic and biotic boundaries. The close interchange, i.e. multiple feedback loops, between hydrologic and biologic controls is also becoming increasingly evident. Holistic approaches are thus necessary for a robust understanding of ecosystem functioning and subsequent implementation of effective management practices across multiple spatial scales. Groundwater and surface water resources are under pressure from increasing global exploitation and anthropogenic impacts such as contamination by chemicals, leading to a severe degradation of essential ecological functions. Many of the environmental problems we face today have existed for decades; what has changed is our understanding of the key drivers, processes and impacts. The first reporting by European Member States (MS) on the status of their water bodies found that rivers and transitional waters were often in worse condition than lakes and coastal waters. This is not surprising considering that streams integrate all of the diverse stressors found within a catchment (e.g. contaminated sites; diffuse source pollution; water abstraction). The chemical status of a water body is relatively straightforward to assess, defined partly by environmental quality standards on priority substances and partly by additional regulations imposed by individual MS. However, the biological quality elements used for the classification of ecological status are only loosely defined, leaving MS free to develop their own assessment tools. Although useful for the individual MS, it impedes methodological standardization across different ecoregions, thus contributing to inconsistencies and data gaps across Europe. Moreover, despite the unambiguous importance of benthic

  11. Chemical complexity induced by efficient ice evaporation in the Barnard 5 molecular cloud

    Science.gov (United States)

    Taquet, V.; Wirström, E. S.; Charnley, S. B.; Faure, A.; López-Sepulcre, A.; Persson, C. M.

    2017-10-01

    Cold gas-phase water has recently been detected in a cold dark cloud, Barnard 5 located in the Perseus complex, by targeting methanol peaks as signposts for ice mantle evaporation. Observed morphology and abundances of methanol and water are consistent with a transient non-thermal evaporation process only affecting the outermost ice mantle layers, possibly triggering a more complex chemistry. Here we present the detection of the complex organic molecules (COMs) acetaldehyde (CH3CHO) and methyl formate (CH3OCHO), as well as formic acid (HCOOH) and ketene (CH2CO), and the tentative detection of di-methyl ether (CH3OCH3) towards the "methanol hotspot" of Barnard 5 located between two dense cores using the single dish OSO 20 m, IRAM 30 m, and NRO 45 m telescopes. The high energy cis-conformer of formic acid is detected, suggesting that formic acid is mostly formed at the surface of interstellar grains and then evaporated. The detection of multiple transitions for each species allows us to constrain their abundances through LTE and non-LTE methods. All the considered COMs show similar abundances between 1 and 10% relative to methanol depending on the assumed excitation temperature. The non-detection of glycolaldehyde, an isomer of methyl formate, with a [glycolaldehyde]/[methyl formate] abundance ratio lower than 6%, favours gas phase formation pathways triggered by methanol evaporation. According to their excitation temperatures derived in massive hot cores, formic acid, ketene, and acetaldehyde have been designated as "lukewarm" COMs whereas methyl formate and di-methyl ether were defined as "warm" species. Comparison with previous observations of other types of sources confirms that lukewarm and warm COMs show similar abundances in low-density cold gas whereas the warm COMs tend to be more abundant than the lukewarm species in warm protostellar cores. This abundance evolution suggests either that warm COMs are indeed mostly formed in protostellar environments and

  12. Health risk evaluation in a population exposed to chemical releases from a petrochemical complex in Thailand.

    Science.gov (United States)

    Kampeerawipakorn, Ormrat; Navasumrit, Panida; Settachan, Daam; Promvijit, Jeerawan; Hunsonti, Potchanee; Parnlob, Varabhorn; Nakngam, Netnapa; Choonvisase, Suppachai; Chotikapukana, Passaornrawan; Chanchaeamsai, Samroeng; Ruchirawat, Mathuros

    2017-01-01

    Emissions from petrochemical industries may contain toxic and carcinogenic compounds that can pose health risk to human populations. The scenario may be worse in developing countries where management of such exposure-health problems is typically not well-implemented and the public may not be well-informed about such health risk. In Thailand, increasing incidences of respiratory diseases and cancers have been reported for the population around a major petrochemical complex, the Map Ta Phut Industrial Estate (MTPIE). This study aimed to systematically investigate an exposure-health risk among these populations. One-hundred and twelve healthy residents living nearby MTPIE and 50 controls located approximately 40km from MTPIE were recruited. Both external and internal exposure doses to benzene and 1,3-butadiene, known to be associated with the types of cancer that are of concern, were measured because they represent exposure to industrial and/or traffic-related emissions. Health risk was assessed using the biomarkers of early biological effects for cancer and inflammatory responses, as well as biomarkers of exposure for benzene and 1,3-butadiene. The exposure levels of benzene and 1,3-butadiene were similar for both the exposed and control groups. This was confirmed by a non-significant difference in the levels of specific urinary metabolites for benzene (trans,trans-muconic acid, t,t-MA) and 1,3-butadiene (monohydroxy-butyl mercapturic acid, MHBMA). Levels of 8-hydroxydeoxyguanosine (8-OHdG) and DNA strand breaks between the two groups were not statistically significantly different. However, functional biomarkers, interleukin-8 (IL-8) expression was significantly higher (pindustrial complex could be causing these functional abnormalities. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Physical-chemical and biocatalytic properties of a proteolytic complex of the preparation "Protepsin"

    Directory of Open Access Journals (Sweden)

    L. V. Antipova

    2016-01-01

    Full Text Available Enzymatic technologies were included strongly into practical activities of the person, the volume of the world market constantly grows and is updated. However the domestic production of enzymatic preparations very lags behind world level that is in many respects connected with insufficient scientific and technical base for a wide circulation of technologies in large-scale production. At the same time there were Russian producers of enzymatic preparations from animal fabrics and bodies for processing of raw materials of an animal origin, according to forecasts, of interest in rational use of resources of an animal origin. In article data on research of properties of the enzymatic preparation "Protepsin" and an assessment of prospects of application are provided in processing of raw materials of an animal origin. The enzymatic preparation "Protepsin" made in the conditions of JSC Plant of Endocrine Enzymes (Rzhavki, Moscow region activity at action on proteins of meat shows, including the strengthened structure, has milk-clotting effect, is active in the field of pH 4,0-6,0 and temperature 20-45zs. The proteinaceous complex includes 4 fractions, 2 from which possess the general proteolytic activity. One of them shows the general proteolytic and milk-clotting activity. Enzymes differ in an amino-acid set and molecular weight. The method of a disk electrophoresis determined molecular-mass structure of "Protepsin". The preparation inactivation conditions guaranteeing its safety in the production technology of foodstuff as active proteolytic enzymes in the course of digestion can cause violations of integrity of fabrics and corresponding diseases are shown. Thus, conditions of use of a perspective proteolytic preparation in technology of a wide range of food of an animal origin are in a complex proved and picked up.

  14. Identification of a chemical that inhibits the mycobacterial UvrABC complex in nucleotide excision repair.

    Science.gov (United States)

    Mazloum, Nayef; Stegman, Melanie A; Croteau, Deborah L; Van Houten, Bennett; Kwon, Nyoun Soo; Ling, Yan; Dickinson, Caitlyn; Venugopal, Aditya; Towheed, Mohammad Atif; Nathan, Carl

    2011-03-01

    Bacterial DNA can be damaged by reactive nitrogen and oxygen intermediates (RNI and ROI) generated by host immunity, as well as by antibiotics that trigger bacterial production of ROI. Thus a pathogen's ability to repair its DNA may be important for persistent infection. A prominent role for nucleotide excision repair (NER) in disease caused by Mycobacterium tuberculosis (Mtb) was suggested by attenuation of uvrB-deficient Mtb in mice. However, it was unknown if Mtb's Uvr proteins could execute NER. Here we report that recombinant UvrA, UvrB, and UvrC from Mtb collectively bound and cleaved plasmid DNA exposed to ultraviolet (UV) irradiation or peroxynitrite. We used the DNA incision assay to test the mechanism of action of compounds identified in a high-throughput screen for their ability to delay recovery of M. smegmatis from UV irradiation. 2-(5-Amino-1,3,4-thiadiazol-2-ylbenzo[f]chromen-3-one) (ATBC) but not several closely related compounds inhibited cleavage of damaged DNA by UvrA, UvrB, and UvrC without intercalating in DNA and impaired recovery of M. smegmatis from UV irradiation. ATBC did not affect bacterial growth in the absence of UV exposure, nor did it exacerbate the growth defect of UV-irradiated mycobacteria that lacked uvrB. Thus, ATBC appears to be a cell-penetrant, selective inhibitor of mycobacterial NER. Chemical inhibitors of NER may facilitate studies of the role of NER in prokaryotic pathobiology.

  15. CHEMICAL AND PHYSICAL PROPERTIES OF THE FORTIFIED WHEAT FLOUR WITH SYNTHETIC FENAEDTA COMPLEX

    Directory of Open Access Journals (Sweden)

    Ali Hussein Abed-Al-Kareem

    2013-08-01

    Full Text Available This study includes fortification of two type of flour 70 and 80 % extraction with two sources of non-haem iron sodium iron EDTA (FeNaEDTA which was synthesis in laboratory and ferrous sulfate in level of 30 mg iron/kg flour. The synthesis FeNaEDTA has been identified in several methods, infra red spectrophotometry, C.H.N analyzer and inductively coupled plasma optical emission spectrometry (ICP- OES. NaFeEDTA is the only non-haem source that has good bioavailability as it is relatively independent of flour composition and withstands the inhibitory effects of phytates. Chemical analysis of the two type of the flour before and after fortification with FeNaEDTA was done (moisture, ash , protein , fat and wet gluten% and the amount of iron as mg/100g.The falling number was not affected by the above fortificants.The values of falling Number of 70% extraction for non-fortified and fortified flour by FeNaEDTA and ferrous sulfate were ( 425,426,427 second respectively, while for 80% extracted flour were (445,446,448 second respectively. The color test showed an increasing of color degree upon fortified by iron sulfate and decreasing of upon fortified by FeNaEDTA in both type of flour.

  16. Quantum-Chemical Insights into the Self-Assembly of Carbon-Based Supramolecular Complexes

    Directory of Open Access Journals (Sweden)

    Joaquín Calbo

    2018-01-01

    Full Text Available Understanding how molecular systems self-assemble to form well-organized superstructures governed by noncovalent interactions is essential in the field of supramolecular chemistry. In the nanoscience context, the self-assembly of different carbon-based nanoforms (fullerenes, carbon nanotubes and graphene with, in general, electron-donor molecular systems, has received increasing attention as a means of generating potential candidates for technological applications. In these carbon-based systems, a deep characterization of the supramolecular organization is crucial to establish an intimate relation between supramolecular structure and functionality. Detailed structural information on the self-assembly of these carbon-based nanoforms is however not always accessible from experimental techniques. In this regard, quantum chemistry has demonstrated to be key to gain a deep insight into the supramolecular organization of molecular systems of high interest. In this review, we intend to highlight the fundamental role that quantum-chemical calculations can play to understand the supramolecular self-assembly of carbon-based nanoforms through a limited selection of supramolecular assemblies involving fullerene, fullerene fragments, nanotubes and graphene with several electron-rich π-conjugated systems.

  17. Oxidative Stress Regulation on Endothelial Cells by Hydrophilic Astaxanthin Complex: Chemical, Biological, and Molecular Antioxidant Activity Evaluation

    Directory of Open Access Journals (Sweden)

    M. Zuluaga

    2017-01-01

    Full Text Available An imbalance in the reactive oxygen species (ROS homeostasis is involved in the pathogenesis of oxidative stress-related diseases. Astaxanthin, a xanthophyll carotenoid with high antioxidant capacities, has been shown to prevent the first stages of oxidative stress. Here, we evaluate the antioxidant capacities of astaxanthin included within hydroxypropyl-beta-cyclodextrin (CD-A to directly and indirectly reduce the induced ROS production. First, chemical methods were used to corroborate the preservation of astaxanthin antioxidant abilities after inclusion. Next, antioxidant scavenging properties of CD-A to inhibit the cellular and mitochondrial ROS by reducing the disturbance in the redox state of the cell and the infiltration of lipid peroxidation radicals were evaluated. Finally, the activation of endogenous antioxidant PTEN/AKT, Nrf2/HO-1, and NQOI gene and protein expression supported the protective effect of CD-A complex on human endothelial cells under stress conditions. Moreover, a nontoxic effect on HUVEC was registered after CD-A complex supplementation. The results reported here illustrate the need to continue exploring the interesting properties of this hydrophilic antioxidant complex to assist endogenous systems to counteract the ROS impact on the induction of cellular oxidative stress state.

  18. Frictional melting dynamics in the upper conduit: A chemical answer to a complex physical question

    Science.gov (United States)

    Henton De Angelis, S.; Lavallee, Y.; Kendrick, J. E.; Hornby, A.; von Aulock, F. W.; Clesham, S.; Hirose, T.; Perugini, D.

    2013-12-01

    During volcanic eruptions the generation of frictional heat along the walls of the shallow conduit leads to melting of the rocks along the slip interface. Frictional melting has previously been described as a process out of thermodynamic equilibrium, but upon slip and mingling of the melt batches, homogeneity can be achieved, and may have an h important rheological control on the dynamics of slip. To test melt homogenization in the frictional melt zones of volcanic conduits we performed constant-rate slip experiments under controlled stress conditions using a high-velocity rotary shear apparatus. Volcanic dome samples from three different volcanoes (Volcán De Colima, Soufrière Hills Volcano and Santiaguito Volcano) were investigated. Each sample was subjected to a stress of 1 MPa and slip rate of 1 m/s. For each sample set 5 experiments were conducted: 1) experiment stopped at the onset of melting; 2) experiment stopped on the formation of a full melt layer; 3) experiment stopped after 5m of slip at steady state conditions; 4) experiment stopped after 10m of slip at steady state conditions; 5) experiment stopped after 15m of slip at steady state conditions. We analyzed the resulting proto-melt zones using micron sized X-ray spectroscopy in the high-brightness synchrotron beamline I18 (at Diamond Light Source UK). Particular focus was given to the concentration variance analysis of Rare Earth Elements as their mobilities can be used to precisely quantify the degree and timescale of homogenisation involved during frictional melting. This study refines our understanding of the chemical process of melting and mixing which carry important consequences for the rheological control on the physical dynamics of slip.

  19. Historic American Engineering Record, Idaho National Laboratory, Idaho Chemical Processing Plant, Fuel Reprocessing Complex

    Energy Technology Data Exchange (ETDEWEB)

    Susan Stacy; Julie Braun

    2006-12-01

    Just as automobiles need fuel to operate, so do nuclear reactors. When fossil fuels such as gasoline are burned to power an automobile, they are consumed immediately and nearly completely in the process. When the fuel is gone, energy production stops. Nuclear reactors are incapable of achieving this near complete burn-up because as the fuel (uranium) that powers them is burned through the process of nuclear fission, a variety of other elements are also created and become intimately associated with the uranium. Because they absorb neutrons, which energize the fission process, these accumulating fission products eventually poison the fuel by stopping the production of energy from it. The fission products may also damage the structural integrity of the fuel elements. Even though the uranium fuel is still present, sometimes in significant quantities, it is unburnable and will not power a reactor unless it is separated from the neutron-absorbing fission products by a method called fuel reprocessing. Construction of the Fuel Reprocessing Complex at the Chem Plant started in 1950 with the Bechtel Corporation serving as construction contractor and American Cyanamid Company as operating contractor. Although the Foster Wheeler Corporation assumed responsibility for the detailed working design of the overall plant, scientists at Oak Ridge designed all of the equipment that would be employed in the uranium separations process. After three years of construction activity and extensive testing, the plant was ready to handle its first load of irradiated fuel.

  20. Chemical speciation and equilibria of some nucleic acid compounds and their iron(III) complexes

    Science.gov (United States)

    Masoud, Mamdouh S.; Abd El-Kaway, Marwa Y.; Hindawy, Ahmed M.; Soayed, Amina A.

    The pH effect on electronic absorption spectra of some biologically active nucleic acid constituents have been studied at room temperature and the mechanism of ionization was explained. These compounds are of two categories (pyrimidines: [barbital; 5,5'-diethyl-barbituric acid], [SBA; 4,6-dihydroxy-2-mercapto-pyrimidin], [NBA; 5-nitro-2,4,6(1H,3H,5H)-pyrimidine trione] and [TU; 2,3-dihydro-2-thioxo-pyrimidin-4(1H)-one]) and (purines: [adenine; 6-amino purine], its [Schiff bases derived from adenine-acetylacetone; (Z)-4-(7H-purin-6-ylimino)pentan-2-one) and adenine-salicylaldehyde; 2-((7H-purin-6-ylimino) methyl) phenol] and its [Azo derived from adenine-resorcinol; 4-((7H-purin-6-yl)-diazenyl) benzene-1,3-diol]. The phenomena of tautomerization assigned different tautomers. Different spectrophotometric methods are applied to evaluate the pK's values that explained with their molecular structures. The interaction of Fe3+ with some selected pyrimidines (barbital, NBA and SBA) was explained using familiar six spectrophotometric methods. The data typified the existence of different absorbing species with the different stoichiometries 1:1, 1:2, 1:3 and 2:3. The stability constant of the complexes was computed. More approach was deduced to assign the existence of different species applying the distribution diagrams.

  1. Efficient Characterization of Parametric Uncertainty of Complex (Bio)chemical Networks.

    Science.gov (United States)

    Schillings, Claudia; Sunnåker, Mikael; Stelling, Jörg; Schwab, Christoph

    2015-08-01

    Parametric uncertainty is a particularly challenging and relevant aspect of systems analysis in domains such as systems biology where, both for inference and for assessing prediction uncertainties, it is essential to characterize the system behavior globally in the parameter space. However, current methods based on local approximations or on Monte-Carlo sampling cope only insufficiently with high-dimensional parameter spaces associated with complex network models. Here, we propose an alternative deterministic methodology that relies on sparse polynomial approximations. We propose a deterministic computational interpolation scheme which identifies most significant expansion coefficients adaptively. We present its performance in kinetic model equations from computational systems biology with several hundred parameters and state variables, leading to numerical approximations of the parametric solution on the entire parameter space. The scheme is based on adaptive Smolyak interpolation of the parametric solution at judiciously and adaptively chosen points in parameter space. As Monte-Carlo sampling, it is "non-intrusive" and well-suited for massively parallel implementation, but affords higher convergence rates. This opens up new avenues for large-scale dynamic network analysis by enabling scaling for many applications, including parameter estimation, uncertainty quantification, and systems design.

  2. Physico-Chemical behaviour analysis of air pollutants in a complex coastal site: Castellon

    International Nuclear Information System (INIS)

    Andres, M. D.; Martin, M.; Plaza, J.; Millan, M.

    1989-01-01

    In January, July and August 1988 two experimental campaigns were launched in the surroundings of the Castellon industrial area located at the Spanish East coast and considered as a complex coastal site. The objective was to complement the mosaic on meso-scale flows on the pollutants concentration fields. A careful study of pollutants concentration cycles related to meteorological parameters, enables the characterization of concentration patterns at the chosen location. Surface atmospheric dynamic in this area in controlled by local cycles of NW nocturnal drainage and E-SSE diumal sea-breeze lows. These cycles are also affected by the formation of thermal low over the center of thee peninsula on summer days. Large scale synoptic conditions appear more frequently during the winter. A transportable laboratory was used to register ten minutes averaged values of O 3 , NO, HO 2 and SO 2 . This unit was placed in the zone of influence of the coastal industries during the sea-breeze regime. The temporal evolution of the pollutant concentrations was analyzed and shows the existence of repeated patters of ground level concentrations under similar meteorological conditions. High ozone values have been detected to be associated with the sea-breeze onset. On the basis of short-term backward trajectories, it has been possible to identity the source of the SO 2 and NO 2 peaks. The obtained concentration values can have a broad origin: rural, marine, traffic, oil fired power plant and refinery emissions, and urban plume. Summer and winder data obtained under similar meteorological conditions have been compared. The temporal evolution of the pollutant concentrations is very similar. (Author) 15 refs

  3. Physico-chemical behaviour analysis of air pollutants in a complex coastal site: Castellon

    International Nuclear Information System (INIS)

    Andres, M.D.; Martin, M.; Plaza, J.; Millan, M.

    1989-01-01

    In Jaunary, July and August 1988 two experimental campaigns were launched in the surroundings of the Castellon industrial area located at the Spanish East coast and considered as a complex coastal site. The objetive was to complement the mosaic on meso-scale flows on the pollutants concentration fields. A careful study of pollutants concentration cycles related to meteorological parameters, enables the characterization of concentration patterns at the chose location. Surface atmospheric dynamic in this area in controlled by local cycles of NW nocturnal drainage and E-SSE diumal sea-breeze flows. These cycles arae also affected by the formation of thermal low over the center of the peninsula on summer days. Large scale synoptic conditions appear more frequently during the winter. A transportable laboratory was used to register ten minutes averaged values of O 3 , NO, NO 2 and SO 2 . This unit was placed in the zone of influence of the coastal industries during the sea-breeze regime. The temporal evolution of the pollutant concentrations was analyzed and shows the existence of repeated patterns of ground level concentrations under similar meteorological conditions. High ozone values have been detected to be associated with the sea-breeze onset. On the basis of short-term backward trajectories, it has been possible ot identify the source of the SO 2 and NO 2 peaks. The obtained concentration values can have a broad origin: rural, marine, traffic, oil fired power plant and refinery emissions, and urban plume. Summer and winter data obtained under similar meteorological conditions have been compared. The temporal evolution of the pollutant concentrations is very similar. (Author)

  4. 1170-MW(t) HTGR-PS/C plant application study report: Geismar, Louisiana refinery/chemical complex application

    International Nuclear Information System (INIS)

    McMain, A.T. Jr.; Stanley, J.D.

    1981-05-01

    This report summarizes a study to apply an 1170-MW(t) high-temperature gas-cooled reactor - process steam/cogeneration (HTGR-PS/C) to an industrial complex at Geismar, Louisiana. This study compares the HTGR with coal and oil as process plant fuels. This study uses a previous broad energy alternative study by the Stone and Webster Corporation on refinery and chemical plant needs in the Gulf States Utilities service area. The HTGR-PS/C was developed by General Atomic (GA) specifically for industries which require both steam and electric energy. The GA 1170-MW(t) HTGR-PC/C design is particularly well suited to industrial applications and is expected to have excellent cost benefits over other energy sources

  5. Chemical equilibrium between particles and complex particles in quantum many-body system at very low temperature

    International Nuclear Information System (INIS)

    Matsumoto, Atsushi

    2004-01-01

    The equilibrium state at very low temperature and phase state at 0 K between the particle 1 and particle 2 and the particle 12, which particle 1 bond with particle 2, of infinite uniform system was investigated. Boson and fermion are thought as particle and three kinds of reactions are considered. On the case of boson + boson ? boson, the system is all molecules or atoms when ΔE≠0 and T=0, and the density is not determined under Tc when ΔE=0. On the case of boson + fermion ? fermion, molecules and atoms are able to exist together at T=0. On fermion + fermion ? boson, molecule is formed and condensed. The chemical equilibrium between particles and complex particles and three cases of equilibrium are explained. (S.Y.)

  6. Valuation of the safety concept of the combined nuclear/chemical complex for hydrogen production with HTTR

    International Nuclear Information System (INIS)

    Verfondern, K.; Nishihara, T.

    2004-06-01

    The high-temperature engineering test reactor (HTTR) in Oarai, Japan, will be worldwide the first plant to demonstrate the production of hydrogen by applying the steam reforming process and using nuclear process heat as primary energy. Particular safety aspects for such a combined nuclear/chemical complex have to be investigated to further detail. One of these special aspects is the fire and explosion hazard associated with the presence of flammable gases including a large LNG storage tank in close vicinity to the reactor building. A special focus is laid upon the conceivable development of a detonation pressure wave and its damaging effect on the reactor building. A literature study has shown that methane is a comparatively slow reacting gas and that a methane vapor cloud in the open atmosphere or partially obstructed areas is highly unlikely to result in a detonation if inadvertently released and ignited. Various theoretical assessments and experimental studies, which have been conducted in the past and which are of significance for the HTTR-steam reforming system, include the spreading and combustion behavior of cryogenic liquids and flammable gas mixtures providing the basis of a comprehensive safety analysis of the combined nuclear/chemical facility. (orig.)

  7. Vanadium NMR Chemical Shifts of (Imido)vanadium(V) Dichloride Complexes with Imidazolin-2-iminato and Imidazolidin-2-iminato Ligands: Cooperation with Quantum-Chemical Calculations and Multiple Linear Regression Analyses.

    Science.gov (United States)

    Yi, Jun; Yang, Wenhong; Sun, Wen-Hua; Nomura, Kotohiro; Hada, Masahiko

    2017-11-30

    The NMR chemical shifts of vanadium ( 51 V) in (imido)vanadium(V) dichloride complexes with imidazolin-2-iminato and imidazolidin-2-iminato ligands were calculated by the density functional theory (DFT) method with GIAO. The calculated 51 V NMR chemical shifts were analyzed by the multiple linear regression (MLR) analysis (MLRA) method with a series of calculated molecular properties. Some of calculated NMR chemical shifts were incorrect using the optimized molecular geometries of the X-ray structures. After the global minimum geometries of all of the molecules were determined, the trend of the observed chemical shifts was well reproduced by the present DFT method. The MLRA method was performed to investigate the correlation between the 51 V NMR chemical shift and the natural charge, band energy gap, and Wiberg bond index of the V═N bond. The 51 V NMR chemical shifts obtained with the present MLR model were well reproduced with a correlation coefficient of 0.97.

  8. Simplified mathematical model for heat supply and removal with allowance for chemical reaction kinetics in the N2O4 reversible 2NO2 reversible 2NO + O2 system

    International Nuclear Information System (INIS)

    Shiryaeva, N.M.

    1977-01-01

    The processes of heat supply and removal with chemical reactions proceeding in the circuit are usually described by a set of nonlinear ordinary differential equations. Considering a non-equilibrium state of a chemically reacting gas relative to equilibrium, to which the nonequilibrium system approaches according to a certain process and applying the Tailor series expansion near this equilibrium point, a set of differential equations can be reduced to one differential and some algebraic equations. The analysis shows that of the differential equation obtained can be quasilinearized, and then the linear differential equation can be solved. On the basis of the analytical solutions obtained the calculations of flow parameters have been performed for the cases of cooling and heating the dissociating coolant in channels of a constant cross-section at various pressures. The calculation results are in a satisfactory agreement with the numerical solution of a set of differential equations performed on the ''Minsk-22'' computer. The solution may be applied to calculate isobaric processes in thermodynamic cycles, where the N 2 O 4 coolant is used

  9. The evaluation of physico-chemical parameters of the Nasrand Plutonic complex by using mineral composition

    Directory of Open Access Journals (Sweden)

    Fatemeh Sarjoughian

    2017-02-01

    -120. Ridolfi, F., Renzulli, A. and Puerini, M., 2010. Stability and chemical equilibrium of amphibole in calc-alkaline magmas: an overview, new thermobarometric formulations and application to subduction-related volcanoes. Contributions to Mineralogy and Petrology, 160(1: 45–66. Schmidt, M.W., 1992. Amphibole composition in tonalite as a function of pressure an experimental calibration of the Al-hornblende barometer. Contributions to Mineralogy and Petrology, 110(2-3: 304-310. Soesoo, A., 1997. A multivariate statistical analysis of clinopyroxene composition: empirical coordinates for the crystallisation PT-estimations. Geological Society of Sweden, 119(1: 55-60. Stein, E. and Dietl, E., 2001. Hornblende thermo barometry of granitoids from the central Odenwald (Germany and their implication for the geotectonic development of the Odenwald. Mineralogy and Petrology, 72(1-3: 185-207. Vyhnal, C.R., Mcsween, H.Y. and Speer, J.A., 1991. Hornblende Chemistry in Southern Appalachian Granitoids: implications for aluminum hornblende thermo barometry and magmatic epidote stability. American Mineralogist, 76(1-2: 176-188.

  10. Initial laboratory studies into the chemical and radiological aging of organic materials in underground storage tanks at the Hanford Complex

    International Nuclear Information System (INIS)

    Samuels, W.D.; Camaioni, D.M.; Babad, H.

    1994-01-01

    The underground storage tanks at the Hanford Complex contain wastes generated over many years from plutonium production and recovery processes, and mixed wastes from radiological degradation processes. The chemical changes of the organic materials used in the extraction processes have a direct bearing on several specific safety issues, including potential energy releases from these tanks. The major portion of organic materials that have been added to the tanks consists of tributyl phosphate, dibutyl phosphate, butyl alcohol, hexone (methyl isobutyl ketone), normal paraffin hydrocarbons (NPH), ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriadetic acid (HEDTA), other complexants, and lesser quantities of ion exchange polymers and minor organic compounds. A study of how thermal and radiological processes that may have changed the composition of organic tanks constituents has been initiated after a review of the open literature revealed little information was available about the rates and products of these processes under basic pH conditions. This paper will detail the initial findings as they relate to gas generation, e.g. H 2 , CO, NH 3 , CH 4 , and to changes in the composition of the organic and inorganic components brought about by ''Aging'' processes

  11. Reversible Communicating Processes

    Directory of Open Access Journals (Sweden)

    Geoffrey Brown

    2016-02-01

    Full Text Available Reversible distributed programs have the ability to abort unproductive computation paths and backtrack, while unwinding communication that occurred in the aborted paths. While it is natural to assume that reversibility implies full state recovery (as with traditional roll-back recovery protocols, an interesting alternative is to separate backtracking from local state recovery. For example, such a model could be used to create complex transactions out of nested compensable transactions where a programmer-supplied compensation defines the work required to "unwind" a transaction. Reversible distributed computing has received considerable theoretical attention, but little reduction to practice; the few published implementations of languages supporting reversibility depend upon a high degree of central control. The objective of this paper is to demonstrate that a practical reversible distributed language can be efficiently implemented in a fully distributed manner. We discuss such a language, supporting CSP-style synchronous communication, embedded in Scala. While this language provided the motivation for the work described in this paper, our focus is upon the distributed implementation. In particular, we demonstrate that a "high-level" semantic model can be implemented using a simple point-to-point protocol.

  12. Structural plasticity: how intermetallics deform themselves in response to chemical pressure, and the complex structures that result.

    Science.gov (United States)

    Berns, Veronica M; Fredrickson, Daniel C

    2014-10-06

    Interfaces between periodic domains play a crucial role in the properties of metallic materials, as is vividly illustrated by the way in which the familiar malleability of many metals arises from the formation and migration of dislocations. In complex intermetallics, such interfaces can occur as an integral part of the ground-state crystal structure, rather than as defects, resulting in such marvels as the NaCd2 structure (whose giant cubic unit cell contains more than 1000 atoms). However, the sources of the periodic interfaces in intermetallics remain mysterious, unlike the dislocations in simple metals, which can be associated with the exertion of physical stresses. In this Article, we propose and explore the concept of structural plasticity, the hypothesis that interfaces in complex intermetallic structures similarly result from stresses, but ones that are inherent in a defect-free parent structure, rather than being externally applied. Using DFT-chemical pressure analysis, we show how the complex structures of Ca2Ag7 (Yb2Ag7 type), Ca14Cd51 (Gd14Ag51 type), and the 1/1 Tsai-type quasicrystal approximant CaCd6 (YCd6 type) can all be traced to large negative pressures around the Ca atoms of a common progenitor structure, the CaCu5 type with its simple hexagonal 6-atom unit cell. Two structural paths are found by which the compounds provide relief to the Ca atoms' negative pressures: a Ca-rich pathway, where lower coordination numbers are achieved through defects eliminating transition metal (TM) atoms from the structure; and a TM-rich path, along which the addition of spacer Cd atoms provides the Ca coordination environments greater independence from each other as they contract. The common origins of these structures in the presence of stresses within a single parent structure highlights the diverse paths by which intermetallics can cope with competing interactions, and the role that structural plasticity may play in navigating this diversity.

  13. Chemical, structural, and electrochemical characterization of 5 V spinel and complex layered oxide cathodes of lithium ion batteries

    Science.gov (United States)

    Tiruvannamalai Annamalai, Arun Kumar

    2007-12-01

    proton insertion and oxygen loss at deep lithium extraction due to the chemical instability arising from a overlap of the Co3+/4+:3d band on the top of the O2-:2p band. The irreversible oxygen loss during the first charge and the consequent reversible capacities of the solid solutions between Li[Li1/3Mn 2/3]O2 and Li[Co1-yNiy]O2 has been found to be determined by the amount of lithium in the transition metal layer of the O3 type layered structure. The lithium content in the transition metal layer is, however, sensitively influenced by the tendency of Ni 3+ to get reduced to Ni2+ and the consequent volatilization of lithium during synthesis. Moreover, high Mn4+ content causes a decrease in oxygen mobility and loss. In addition, the chemically delithiated samples were found to adopt either the parent O3 type structure or the new P3 or O1 type structures depending upon the composition and synthesis temperature of the parent samples and the proton content inserted into the delithiated sample. In essence, the chemical and structural stabilities and the electrochemical performance factors of the layered (1-z) Li[Li1/3 Mn2/3]O2 · (z) Li[Co1-yNi y]O2 solid solution cathodes are found to be maximized by optimizing the contents of the various ions.

  14. Assessment of chemical element migration in soil-plant complex of Urov endemic localities of East Transbaikalia

    Science.gov (United States)

    Vadim V., Ermakov; Valentina, Danilova; Sabsbakhor, Khushvakhtova; Aklexander, Degtyarev; Sergey, Tyutikov; Victor, Berezkin; Elena, Karpova

    2014-05-01

    The comparative evaluation of the levels of biologically active chemical elements and their migration in the soil-plant complex of two Urov endemic locations in East Transbaikalia (Zolinsky and Uryumkansky) and background areas (Western Baikal region and the western area of the Trans-Baikal region) was conducted. The predominant soil-forming rocks in East Transbaikalia are weathering products of Proterozoic carbonated granitoids PR2. The surface rocks consist from granite, granodiorite, diorite quartz diorite, gabbro, norite, gabbro-norite and other. Soils - mountain and cryogenic meadow forests, mountain permafrost taiga podzolised, meadow alluvial, peaty meadow [2]. The paludification of narrow valleys and thermokarst phenomena are typical in Urov endemic localities. It reflects on the spotted of soil and differentiation of chemical composition of soils and plants. Most of the chemical elements in soils were determined by means of X-ray fluorescence, and trace elements in soils and plants - by atomic absorption spectrometry. The selenium content was measured by spectrofluorimetric method [3]. The research processed by methods of variation statistics. It was found that the soils of two locations of the Urov subregion of the biosphere were more enriched with iron, barium, calcium, uranium, thorium, phosphorus, and to a lesser extent strontium compared to background soils. The ratio of Ca: P was significantly higher in the soil of background areas, and Ca: Sr, on the contrary, in endemic soils. In assessing the migration of trace elements in soil-plant complex by means of the total content of trace elements and biological absorption coefficient found a marked accumulation by plants manganese, chromium, arsenic and weak plants accumulation of cobalt and nickel. Soil landscape is not much different in content of selenium, but its migration in plants was reduced in places of spread of Urov disease [1]. The concentrators of cadmium (leaves of different species of willow

  15. A new complex vector method for balancing chemical equations: Nova kompleksna metoda za uravnoteženje kemičnih enačb:

    OpenAIRE

    Risteski, Ice B.

    2010-01-01

    In this article, the author discovers a paradox of balancing chemical equations. The many counterexamples illustrate that the considered procedure of balancing chemical equations given in the paper1 is inconsistent. A new complex vector method for paradox resolution is given too. V članku avtor opisuje paradoks pri uravnoteženju kemijskih reakcij. Več primerov dokazuje, da je procedura uravnoteženja kemijskih reakcij v viru1 inkonsistentna. Predstavljena je nova kompleksna vektorska metoda...

  16. REMOVAL OF CHEMICAL AND MICROBIAL CONTAMINANTS IN DRINKING WATER - WATTS PREMIER M-2400 POINT-OF-ENTRY REVERSE OSMOSIS DRINKINGWATER TREATMENT SYSTEM

    Science.gov (United States)

    The Watts Premier M-2400 POE RO Drinking Water Treatment System was tested at the NSF Drinking Water Treatment Systems Laboratory for removal of the viruses fr and MS2, the bacteria Brevundimonas diminuta, and chemicals aldicarb, benzene, cadmium, carbofuran, cesium, chl...

  17. Controlling the quality of nanocrystalline silicon made by hot-wire chemical vapor deposition by using a reverse H2 profiling technique

    NARCIS (Netherlands)

    Li, H. B. T.; Franken, R.H.; Stolk, R.L.; van der Werf, C.H.M.; Rath, J.K.; Schropp, R.E.I.

    2008-01-01

    Hydrogen profiling, i.e., decreasing the H2 dilution during deposition, is a well-known technique to maintain a proper crystalline ratio of the nanocrystalline (nc-Si:H) absorber layers of plasma-enhanced chemical vapor-deposited (PECVD) thin film solar cells. With this technique a large increase in

  18. Assessment of multiple sources of anthropogenic and natural chemical inputs to a morphologically complex basin, Lake Mead, USA

    Science.gov (United States)

    Rosen, Michael R.; Van Metre, P.C.

    2010-01-01

    Lakes with complex morphologies and with different geologic and land-use characteristics in their sub-watersheds could have large differences in natural and anthropogenic chemical inputs to sub-basins in the lake. Lake Mead in southern Nevada and northern Arizona, USA, is one such lake. To assess variations in chemical histories from 1935 to 1998 for major sub-basins of Lake Mead, four sediment cores were taken from three different parts of the reservoir (two from Las Vegas Bay and one from the Overton Arm and Virgin Basin) and analyzed for major and trace elements, radionuclides, and organic compounds. As expected, anthropogenic contaminant inputs are greatest to Las Vegas Bay reflecting inputs from the Las Vegas urban area, although concentrations are low compared to sediment quality guidelines and to other USA lakes. One exception to this pattern was higher Hg in the Virgin Basin core. The Virgin Basin core is located in the main body of the lake (Colorado River channel) and is influenced by the hydrology of the Colorado River, which changed greatly with completion of Glen Canyon Dam upstream in 1963. Major and trace elements in the core show pronounced shifts in the early 1960s and, in many cases, gradually return to concentrations more typical of pre-1960s by the 1980s and 1990s, after the filling of Lake Powell. The Overton Arm is the sub-basin least effected by anthropogenic contaminant inputs but has a complex 137Cs profile with a series of large peaks and valleys over the middle of the core, possibly reflecting fallout from nuclear tests in the 1950s at the Nevada Test Site. The 137Cs profile suggests a much greater sedimentation rate during testing which we hypothesize results from greatly increased dust fall on the lake and Virgin and Muddy River watersheds. The severe drought in the southwestern USA during the 1950s might also have played a role in variations in sedimentation rate in all of the cores. ?? 2009.

  19. Chemical interactions in complex matrices: Determination of polar impurities in biofuels and fuel contaminants in building materials

    Science.gov (United States)

    Baglayeva, Ganna

    The solutions to several real-life analytical and physical chemistry problems, which involve chemical interactions in complex matrices are presented. The possible interferences due to the analyte-analyte and analyte-matrix chemical interactions were minimized on each step of the performed chemical analysis. Concrete and wood, as major construction materials, typically become contaminated with fuel oil hydrocarbons during their spillage. In the catastrophic scenarios (e.g., during floods), fuel oil mixes with water and then becomes entrained within the porous structure of wood or concrete. A strategy was proposed for the efficient extraction of fuel oil hydrocarbons from concrete to enable their monitoring. The impacts of sample aging and inundation with water on the extraction efficiency were investigated to elucidate the nature of analytematrix interactions. Two extraction methods, 4-days cold solvent extraction with shaking and 24-hours Soxhlet extraction with ethylacetate, methanol or acetonitrile yielded 95-100 % recovery of fuel oil hydrocarbons from concrete. A method of concrete remediation after contamination with fuel oil hydrocarbons using activated carbon as an adsorbent was developed. The 14 days remediation was able to achieve ca. 90 % of the contaminant removal even from aged water-submerged concrete samples. The degree of contamination can be qualitatively assessed using transport rates of the contaminants. Two models were developed, Fickian and empirical, to predict long-term transport behavior of fuel oil hydrocarbons under flood representative scenarios into wood. Various sorption parameters, including sorption rate, penetration degree and diffusion coefficients were obtained. The explanations to the observed three sorption phases are provided in terms of analyte-matrix interactions. The detailed simultaneous analysis of intermediate products of the cracking of triacylglycerol oils, namely monocarboxylic acids, triacyl-, diacyl- and

  20. Evaluating the impacts of membrane type, coating, fouling, chemical properties and water chemistry on reverse osmosis rejection of seven nitrosoalklyamines, including NDMA.

    Science.gov (United States)

    Steinle-Darling, Eva; Zedda, Marco; Plumlee, Megan H; Ridgway, Harry F; Reinhard, Martin

    2007-09-01

    Reverse osmosis (RO) treatment has been found to be effective for a wide range of organics but generally small, polar, uncharged molecules such as N-nitrosodimethylamine (NDMA) can be poorly rejected. The rejection of seven N-nitrosoalkylamines with molecular masses in the range of 78-158Da, including NDMA, N-nitrosodiethylamine (NDEA), N-nitrosomethylethylamine (NMEA), N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA), N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip) by three commercial brackish-water reverse osmosis membranes was studied in flat-sheet cells under cross-flow conditions. The membranes used were ESPA3 (Hydranautics), LFC3 (Hydranautics) and BW-30 (Dow/Filmtec), commonly used in water reuse applications. The effects of varying ionic strength and pH, dip-coating membranes with PEBAX 1657, a hydrophilic polymer, and artificial fouling with alginate on nitrosamine rejection were quantified. Rejection in deionized (DI) water increased with molecular mass from 56 to 70% for NDMA, to 80-91% for NMEA, 89-97% for NPyr, 92-98% for NDEA, and to beyond the detection limits for NPip, NDPA and NDBA. For the nitrosamines with quantifiable transmission, linear correlations (r(2)>0.97) were found between the number of methyl groups and the log(transmission), with factor 0.35 to 0.55 decreases in transmission per added methyl group. A PEBAX coating lowered the ESPA3 rejection of NDMA by 11% but increased the LFC3 and BW30 rejection by 6% and 15%, respectively. Artificially fouling ESPA3 membrane coupons with 170g/m(2) alginate decreased the rejection of NDMA by 18%. A feed concentration of 100mM NaCl decreased rejection of NDMA by 15% and acidifying the DI water feed to pH=3 decreased the rejection by 5%, whereas increasing the pH to 10 did not have a significant (p<0.05) effect.

  1. Behavior of new complexes of tetrakis(4-methoxylphenyl)porphyrin with heavy rare earth elements in reversed-phase high performance liquid chromatography.

    Science.gov (United States)

    Zhang, Jun-Feng; Wang, Hong; Hou, An-Xin; Wang, Chang-Fa; Zhang, Hua-Shan

    2004-08-01

    An HPLC method has been developed for the separation of new complexes of tetrakis(4-methoxylphenyl)porphyrin (TMOPP) with four heavy rare earth elements (RE = Y, Er, Tm, and Yb). The function of amine and acid in the mobile phase has been investigated and a reasonable explanation is presented. Successful separation of the RE-TMOPP-Cl complexes is accomplished in 10 min with a mobile phase consisting of methanol-water-acetic acid-triethanolamine. The detection limits (S/N= 3) for the four complexes are 0.01 microg/mL. This method is rapid, sensitive, and simple.

  2. Influence of complexing agent (Na2EDTA on chemical bath deposited Cu4SnS4 thin films

    Directory of Open Access Journals (Sweden)

    Anuar Kassim

    2010-08-01

    Full Text Available The quality of thin film is influenced by the presence of complexing agents such as Na2EDTA. The Cu4SnS4 thin films were deposited onto indium tin oxide glass substrate by chemical bath deposition method. The structural, morphological and optical properties of the deposited films have been studied using X-ray diffraction, atomic force microscopy and UV-Vis spectrophotometer, respectively. The XRD data showed that the films have a polycrystalline and orthorhombic structure. It also indicated that the most intense peak at 2 θ = 30.2° which belongs to (221 plane of Cu4 SnS4. The film deposited with 0.05 M Na2 EDTA showed good uniformity, good surface coverage with bigger grains and produced higher absorbance value. The band gap energy varies with the variation of Na2EDTA concentration which ranging from 1.56-1.60 eV. Deposition at concentration of 0.05 M Na2EDTA proved to offer a reasonably good Cu4SnS4 thin film.

  3. Kinetic, spectroscopic and chemical modification study of iron release from transferrin; iron(III) complexation to adenosine triphosphate

    International Nuclear Information System (INIS)

    Thompson, C.P.

    1985-01-01

    Amino acids other than those that serve as ligands have been found to influence the chemical properties of transferrin iron. The catalytic ability of pyrophosphate to mediate transferrin iron release to a terminal acceptor is largely quenched by modification non-liganded histine groups on the protein. The first order rate constants of iron release for several partially histidine modified protein samples were measured. A statistical method was employed to establish that one non-liganded histidine per metal binding domain was responsible for the reduction in rate constant. These results imply that the iron mediated chelator, pyrophosphate, binds directly to a histidine residue on the protein during the iron release process. EPR spectroscopic results are consistent with this interpretation. Kinetic and amino acid sequence studies of ovotransferrin and lactoferrin, in addition to human serum transferrin, have allowed the tentative assignment of His-207 in the N-terminal domain and His-535 in the C-terminal domain as the groups responsible for the reduction in rate of iron release. The above concepts have been extended to lysine modified transferrin. Complexation of iron(II) to adenosine triphosphate (ATP) was also studied to gain insight into the nature of iron-ATP species present at physiological pH. 31 P NMR spectra are observed when ATP is presented in large excess

  4. How computational methods and relativistic effects influence the study of chemical reactions involving Ru-NO complexes?

    Science.gov (United States)

    Orenha, Renato Pereira; Santiago, Régis Tadeu; Haiduke, Roberto Luiz Andrade; Galembeck, Sérgio Emanuel

    2017-05-05

    Two treatments of relativistic effects, namely effective core potentials (ECP) and all-electron scalar relativistic effects (DKH2), are used to obtain geometries and chemical reaction energies for a series of ruthenium complexes in B3LYP/def2-TZVP calculations. Specifically, the reaction energies of reduction (A-F), isomerization (G-I), and Cl - negative trans influence in relation to NH 3 (J-L) are considered. The ECP and DKH2 approaches provided geometric parameters close to experimental data and the same ordering for energy changes of reactions A-L. From geometries optimized with ECP, the electronic energies are also determined by means of the same ECP and basis set combined with the computational methods: MP2, M06, BP86, and its derivatives, so as B2PLYP, LC-wPBE, and CCSD(T) (reference method). For reactions A-I, B2PLYP provides the best agreement with CCSD(T) results. Additionally, B3LYP gave the smallest error for the energies of reactions J-L. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Structure, vibrations and quantum chemical investigations of hydrogen bonded complex of bis(1-hydroxy-2-methylpropan-2-aminium)selenate

    Science.gov (United States)

    Thirunarayanan, S.; Arjunan, V.; Marchewka, M. K.; Mohan, S.

    2017-04-01

    The hydrogen bonded molecular complex bis(1-hydroxy-2-methylpropan-2-aminium)selenate (C8H24N2O6Se) has been prepared by the reaction of 2-amino-2-methyl propanol and selenic acid. The X-ray diffraction analysis revealed that the intermolecular proton transfer from selenic acid (SeO4H2) to 2-amino-2-methylpropanol results in the formation of bis(1-hydroxy-2-methylpropan-2-aminium)selenate (HMPAS) salt and the fragments are connected through H-bonding and ion pairing. The N-H⋯O and O-H⋯O interactions between 2-amino-2-methylpropanol and selenic acid determine the supramolecular arrangement in three-dimensional space. The salt crystallises in the space group P121/n1 of monoclinic system. The complete vibrational assignments of HMPAS have been performed by FTIR and FT-Raman spectroscopy. The experimental data are correlated with the structural properties namely the energy, thermodynamic parameters, atomic charges, hybridization concepts and vibrational frequencies determined by quantum chemical studies performed with B3LYP method using 6-311++G*, 6-31+G* and 6-31G** basis sets.

  6. Rapid and reversible epigenome editing by endogenous chromatin regulators.

    Science.gov (United States)

    Braun, Simon M G; Kirkland, Jacob G; Chory, Emma J; Husmann, Dylan; Calarco, Joseph P; Crabtree, Gerald R

    2017-09-15

    Understanding the causal link between epigenetic marks and gene regulation remains a central question in chromatin biology. To edit the epigenome we developed the FIRE-Cas9 system for rapid and reversible recruitment of endogenous chromatin regulators to specific genomic loci. We enhanced the dCas9-MS2 anchor for genome targeting with Fkbp/Frb dimerizing fusion proteins to allow chemical-induced proximity of a desired chromatin regulator. We find that mSWI/SNF (BAF) complex recruitment is sufficient to oppose Polycomb within minutes, leading to activation of bivalent gene transcription in mouse embryonic stem cells. Furthermore, Hp1/Suv39h1 heterochromatin complex recruitment to active promoters deposits H3K9me3 domains, resulting in gene silencing that can be reversed upon washout of the chemical dimerizer. This inducible recruitment strategy provides precise kinetic information to model epigenetic memory and plasticity. It is broadly applicable to mechanistic studies of chromatin in mammalian cells and is particularly suited to the analysis of endogenous multi-subunit chromatin regulator complexes.Understanding the link between epigenetic marks and gene regulation requires the development of new tools to directly manipulate chromatin. Here the authors demonstrate a Cas9-based system to recruit chromatin remodelers to loci of interest, allowing rapid, reversible manipulation of epigenetic states.

  7. A theory for bioinorganic chemical reactivity of oxometal complexes and analogous oxidants: the exchange and orbital-selection rules.

    Science.gov (United States)

    Usharani, Dandamudi; Janardanan, Deepa; Li, Chunsen; Shaik, Sason

    2013-02-19

    Over the past decades metalloenzymes and their synthetic models have emerged as an area of increasing research interest. The metalloenzymes and their synthetic models oxidize organic molecules using oxometal complexes (OMCs), especially oxoiron(IV)-based ones. Theoretical studies have helped researchers to characterize the active species and to resolve mechanistic issues. This activity has generated massive amounts of data on the relationship between the reactivity of OMCs and the transition metal's identity, oxidation state, ligand sphere, and spin state. Theoretical studies have also produced information on transition state (TS) structures, reaction intermediates, barriers, and rate-equilibrium relationships. For example, the experimental-theoretical interplay has revealed that nonheme enzymes carry out H-abstraction from strong C-H bonds using high-spin (S = 2) oxoiron(IV) species with four unpaired electrons on the iron center. However, other reagents with higher spin states and more unpaired electrons on the metal are not as reactive. Still other reagents carry out these transformations using lower spin states with fewer unpaired electrons on the metal. The TS structures for these reactions exhibit structural selectivity depending on the reactive spin states. The barriers and thermodynamic driving forces of the reactions also depend on the spin state. H-Abstraction is preferred over the thermodynamically more favorable concerted insertion into C-H bonds. Currently, there is no unified theoretical framework that explains the totality of these fascinating trends. This Account aims to unify this rich chemistry and understand the role of unpaired electrons on chemical reactivity. We show that during an oxidative step the d-orbital block of the transition metal is enriched by one electron through proton-coupled electron transfer (PCET). That single electron elicits variable exchange interactions on the metal, which in turn depend critically on the number of

  8. Reversible Statistics

    DEFF Research Database (Denmark)

    Tryggestad, Kjell

    2004-01-01

    The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit...... in different ways. The presence and absence of diverse materials, both natural and political, is what distinguishes them from each other. Arguments are presented for a more symmetric relation between the scientific statistical text and the reader. I will argue that a more symmetric relation can be achieved...

  9. MODELS OF PROJECT REVERSE ENGINEERING

    Directory of Open Access Journals (Sweden)

    Віктор Володимирович ІВАНОВ

    2017-03-01

    Full Text Available Reverse engineering decided important scientific and technical problems of increasing the cost of the existing technical product by transforming it into a product with other features or design. Search ideas of the new application of existing products on the base of heuristic analysis were created. The concept of reverse engineering and its division into three types: conceptual, aggregate and complete was expanded. The use of heuristic methods for reverse engineering concept was showed. The modification model of Reverse engineering based on the model of РМВОК was developed. Our model includes two new phases: identification and transformation. At the identification phase, technical control is made. At the transformation phase, search heuristic idea of the new applied existing technical product was made. The model of execution phase that included heuristic methods, metrological equipment, and CAD/CAM/CAE program complex was created. The model that connected economic indicators of reverse engineering project was developed.

  10. Effects of CPAP-therapy on brain electrical activity in obstructive sleep apneic patients: a combined EEG study using LORETA and Omega complexity : reversible alterations of brain activity in OSAS.

    Science.gov (United States)

    Toth, Marton; Faludi, Bela; Kondakor, Istvan

    2012-10-01

    Effects of initiation of continuous positive airway pressure (CPAP) therapy on EEG background activity were investigated in patients with obstructive sleep apnea syndrome (OSAS, N = 25) to test possible reversibility of alterations of brain electrical activity caused by chronic hypoxia. Normal control group (N = 14) was also examined. Two EEG examinations were done in each groups: at night and in the next morning. Global and regional (left vs. right, anterior vs. posterior) measures of spatial complexity (Omega complexity) were used to characterize the degree of spatial synchrony of EEG. Low resolution electromagnetic tomography (LORETA) was used to localize generators of EEG activity in separate frequency bands. Before CPAP-treatment, a significantly lower Omega complexity was found globally and over the right hemisphere. Due to CPAP-treatment, these significant differences vanished. Significantly decreased Omega complexity was found in the anterior region after treatment. LORETA showed a decreased activity in all of the beta bands after therapy in the right hippocampus, premotor and temporo-parietal cortex, and bilaterally in the precuneus, paracentral and posterior cingulate cortex. No significant changes were seen in control group. Comparing controls and patients before sleep, an increased alpha2 band activity was seen bilaterally in the precuneus, paracentral and posterior cingulate cortex, while in the morning an increased beta3 band activity in the left precentral and bilateral premotor cortex and a decreased delta band activity in the right temporo-parietal cortex and insula were observed. These findings indicate that effect of sleep on EEG background activity is different in OSAS patients and normal controls. In OSAS patients, significant changes lead to a more normal EEG after a night under CPAP-treatment. Compensatory alterations of brain electrical activity in regions associated with influencing sympathetic outflow, visuospatial abilities, long

  11. Monitoring of radionuclides in the forest ecosystems of the Krasnoyarsk region in the 30 km area around the mining and chemical complex

    International Nuclear Information System (INIS)

    Dement'eva, D.V.; Bolsunovskij, A.Ya.

    2010-01-01

    The study addresses accumulation of radionuclides by mushrooms and berry shrubs in the forest ecosystems around the mining and chemical complex (MCC, Krasnoyarsk region, Russia). Results of determination of radionuclide levels in mushrooms and shrubs were used to calculate transfer factors. (authors)

  12. Comparison of Escherichia coli tRNAPhe in the free state, in the ternary complex and in the ribosomal A and P sites by chemical probing

    DEFF Research Database (Denmark)

    Douthwaite, S; Garrett, R A; Wagner, R

    1983-01-01

    tRNAPheE.coli was modified at accessible guanosine, cytidine, and adenosine residues using the chemical modification method described by Peattie and Gilbert [Proc. Natl Acad. Sci. USA, 77, 4679-4689 (1980)]. Modification characteristics of the tRNA in the free state, in the ternary complex...

  13. Separation and characterization of chemical constituents in Ginkgo biloba extract by off-line hydrophilic interaction×reversed-phase two-dimensional liquid chromatography coupled with quadrupole-time of flight mass spectrometry.

    Science.gov (United States)

    Ji, Shuai; He, Dan-Dan; Wang, Tian-Yun; Han, Jie; Li, Zheng; Du, Yan; Zou, Jia-Hui; Guo, Meng-Zhe; Tang, Dao-Quan

    2017-11-30

    Ginkgo biloba extract (GBE), derived from the leaves of Ginkgo biloba L., is one of the most widely used traditional Chinese medicines worldwide. Due to high structural diversity and low abundance of chemical constituents in GBE, conventional reversed-phase liquid chromatography has limited power to meet the needs of its quality control. In this study, an off-line hydrophilic interaction×reversed-phase two-dimensional liquid chromatography (HILIC×RP 2D-LC) system coupled with diode array detection (DAD) and quadrupole time-of-flight mass spectrometry (qTOF-MS) was established to comprehensively analyze the chemical constituents of GBE. After optimizing the chromatographic columns and mobile phase of 2D-LC, a Waters XBridge Amide column using acetonitrile/water/formic acid as the mobile phase was selected as the first dimension to fractionate GBE, and the obtained fractions were further separated on an Agilent Zorbax XDB-C18 column with methanol/water/formic acid as the mobile phase. As a result, a total of 125 compounds were detected in GBE. The orthogonality of the 2D-LC system was 69.5%, and the practical peak capacity was 3864 and 2994, respectively, calculated by two different methods. The structures of 104 compounds were tentatively characterized by qTOF-MS analysis, and 21 of them were further confirmed by comparing with reference standards. This established HILIC×RP 2D-LC-qTOF/MS system can greatly improve the separation and characterization of natural products in GBE or other complicated herbal extracts. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Reversible and pH dependent photophysical properties of mixed-ligand Ru(II) complexes containing 2,20-bipyridine and nitrosobarbiturate: Experimental and theoretical approach

    Czech Academy of Sciences Publication Activity Database

    Dixit, N.; Záliš, Stanislav; Maiti, B.; Mishra, L.

    2013-01-01

    Roč. 404, AUG 2013 (2013), s. 123-130 ISSN 0020-1693 Institutional support: RVO:61388955 Keywords : Mixed-ligand Ru(II) complex * spectroscopy * X-ray diffraction Subject RIV: CF - Physical ; The oretical Chemistry Impact factor: 2.041, year: 2013

  15. A highly effective in vivo photothermal nanoplatform with dual imaging-guided therapy of cancer based on the charge reversal complex of dye and iron oxide

    NARCIS (Netherlands)

    Chang, Y.; Li, X.; Kong, X.; Li, Y.; Liu, X.; Zhang, Y.; Tu, L.; Xue, B.; Wu, F.; Cao, D.; Zhao, H.; Zhang, H.

    2015-01-01

    To enhance the treatment efficiency of photothermal therapy (PTT) with very little light-associated side effect, we have constructed a highly effective PTT nanoplatform for fluorescence and MRI dual imaging-guided PTT of cancer, based on IR806 dye and iron oxide complex functionalized with

  16. The unique field experiments on the assessment of accident consequences at industrial enterprises of gas-chemical complexes

    International Nuclear Information System (INIS)

    Belov, N.S.; Trebin, I.S.; Sorokovikova, O.

    1998-01-01

    Sour natural gas fields are the unique raw material base for setting up such large enterprises as gas chemical complexes. The presence of high toxic H 2 S in natural gas results in widening a range of dangerous and harmful factors for biosphere. Emission of such gases into atmosphere during accidents at gas wells and gas pipelines is of especial danger for environment and first of all for people. Development of mathematical forecast models for assessment of accidents progression and consequences is one of the main elements of works on safety analysis and risk assessment. The critical step in development of such models is their validation using the experimental material. Full-scale experiments have been conducted by the All-Union Scientific-Research institute of Natural Gases and Gas Technology (VNIIGAZ) for grounding of sizes of hazard zones in case of the severe accidents with the gas pipelines. The source of emergency gas release was the working gas pipelines with 100 mm dia. And 110 km length. This pipeline was used for transportation of natural gas with significant amount of hydrogen sulphide. During these experiments significant quantities of the gas including H 2 S were released into the atmosphere and then concentrations of gas and H 2 S were measured in the accident region. The results of these experiments are used for validation of atmospheric dispersion models including the new Lagrangian trace stochastic model that takes into account a wide range of meteorological factors. This model was developed as a part of computer system for decision-making support in case of accident release of toxic gases into atmosphere at the enterprises of Russian gas industry. (authors)

  17. Scandium complexes: physico-chemical study and evaluation of stability in vitro and in vivo for nuclear medicine application

    International Nuclear Information System (INIS)

    Kerdjoudj, Rabha

    2014-01-01

    Among the different isotopes of Scandium that can be used in nuclear medicine may be mentioned the 47 Sc and 44 Sc. The first decays by emitting an electron associated with a 159 keV gamma can thus be used either for radiotherapy or TEMP imaging. The 44 Sc (3.97 h) decays in 94.27% in case by emitting a positron, with a γ photon energy equal to 1.157 MeV. This isotope is then an ideal candidate for applications in PET imaging. Currently, the Cyclotron of high energy and high intensity ARRONAX produce 44 Sc and co-produces the isomeric state the 44m Sc (2.44 d). The 44m Sc has properties (E(γ) = 270 keV, 98.8%), which allows to consider its use as a potential in vivo generator. Previous work had demonstrated that the DOTA ligand is most suitable and stable for Sc. This thesis aims; make in evidence the feasibility of the in vivo 44m / 44 Sc generator. Initially a procedure was optimized and validated for the production of 44m / 44 Sc with a high specific activity and chemical purity. Radiolabeling of DOTA conjugated peptides was then developed and optimized. Theoretical and experimental studies have been performed in order to demonstrate the feasibility of 44m / 44 Sc as a potential in vivo generator. Finally, in vitro stability studies on radiolabeled 44m / 44 Sc complexes were performed, followed by biodistribution studies and PET imaging. (author)

  18. Radiation in complex exposure situations. Assessing health risks at low levels from concomitant exposures to radiation and chemicals

    International Nuclear Information System (INIS)

    Hornhardt, S.; Jung, T.; Burkart, W.

    2000-01-01

    Health effects from exposures to ionizing radiation are in general the result of complex multi-step reaction chains involving changes and responses on the level of molecules, cells, tissues and organisms. In environmental low dose exposure situations ionizing radiation only contributes a small fraction to the life-long attack on DNA by other exogenous and endogenous genotoxins. Nevertheless, efforts to assess and quantify deleterious effects at low exposure levels are directed mainly towards radiation as a single isolated agent, and rarely towards the concomitant presence of other natural and anthropogenic toxicants. Only these combined exposures may lead to observable health risk effects. In addition they might differ from those expected from simple addition of the individual risks due to interaction. The existing data base on combined effects is rudimentary, mainly descriptive and rarely covers exposure ranges large enough to make direct inferences to present day low dose exposure situations. Therefore, any risk assessment will have to consider the question whether combined effects, i.e. interaction between two or more agents will influence the health outcome from specific exposure situations in such a way that predictions derived from simple standard exposure situations would have to be revised. In view of the multitude of possible interactions between the large number of potentially harmful agents in the human environment, descriptive approaches will have to be supplemented by the use of mechanistic models for critical health endpoints such as cancer. Agents will have to be grouped depending on their physical or chemical mode of action at the molecular and cellular level, to generalize and predict the outcome of combined exposures at low exposure levels and the possibility of interactions. (author)

  19. Systematic Constraint Selection Strategy for Rate-Controlled Constrained-Equilibrium Modeling of Complex Nonequilibrium Chemical Kinetics

    Science.gov (United States)

    Beretta, Gian Paolo; Rivadossi, Luca; Janbozorgi, Mohammad

    2018-04-01

    Rate-Controlled Constrained-Equilibrium (RCCE) modeling of complex chemical kinetics provides acceptable accuracies with much fewer differential equations than for the fully Detailed Kinetic Model (DKM). Since its introduction by James C. Keck, a drawback of the RCCE scheme has been the absence of an automatable, systematic procedure to identify the constraints that most effectively warrant a desired level of approximation for a given range of initial, boundary, and thermodynamic conditions. An optimal constraint identification has been recently proposed. Given a DKM with S species, E elements, and R reactions, the procedure starts by running a probe DKM simulation to compute an S-vector that we call overall degree of disequilibrium (ODoD) because its scalar product with the S-vector formed by the stoichiometric coefficients of any reaction yields its degree of disequilibrium (DoD). The ODoD vector evolves in the same (S-E)-dimensional stoichiometric subspace spanned by the R stoichiometric S-vectors. Next we construct the rank-(S-E) matrix of ODoD traces obtained from the probe DKM numerical simulation and compute its singular value decomposition (SVD). By retaining only the first C largest singular values of the SVD and setting to zero all the others we obtain the best rank-C approximation of the matrix of ODoD traces whereby its columns span a C-dimensional subspace of the stoichiometric subspace. This in turn yields the best approximation of the evolution of the ODoD vector in terms of only C parameters that we call the constraint potentials. The resulting order-C RCCE approximate model reduces the number of independent differential equations related to species, mass, and energy balances from S+2 to C+E+2, with substantial computational savings when C ≪ S-E.

  20. Developing a Highly Active Blood Anticoagulant—a Heparin Complex with Glutamic Acid—by Simulating Chemical Equilibria Based on pH-Metric Data

    Science.gov (United States)

    Nikolaeva, L. S.; Semenov, A. N.

    2018-02-01

    The anticoagulant activity of high-molecular-weight heparin is increased by developing a new highly active heparin complex with glutamate using the thermodynamic model of chemical equilibria based on pH-metric data. The anticoagulant activity of the developed complexes is estimated in the pH range of blood plasma according to the drop in the calculated equilibrium Ca2+ concentration associated with the formation of mixed ligand complexes of Ca2+ ions, heparin (Na4hep), and glutamate (H2Glu). A thermodynamic model is calculated by mathematically modelling chemical equilibria in the CaCl2-Na4hep-H2Glu-H2O-NaCl system in the pH range of 2.30 ≤ pH ≤ 10.50 in diluted saline that acts as a background electrolyte (0.154 M NaCl) at 37°C and initial concentrations of the main components of ν × 10-3 M, where n ≤ 4. The thermodynamic model is used to determine the main complex of the monomeric unit of heparin with glutamate (HhepGlu5-) and the most stable mixed ligand complex of Ca2+ with heparin and glutamate (Ca2hepGlu2-) in the pH range of blood plasma (6.80 ≤ pH ≤ 7.40). It is concluded that the Ca2hepGlu2- complex reduces the Ca2+ concentration 107 times more than the Ca2+ complex with pure heparin. The anticoagulant effect of the developed HhepGlu5- complex is confirmed in vitro and in vivo via coagulation tests on the blood plasma of laboratory rats. Additional antithrombotic properties of the developed complex are identified. The new highly active anticoagulant, HhepGlu5- complex with additional antithrombotic properties, is patented.

  1. Substrate-induced stable enzyme-inhibitor complex formation allows tight binding of novel 2-aminopyrimidin-4(3H)-ones to drug-resistant HIV-1 reverse transcriptase mutants.

    Science.gov (United States)

    Samuele, Alberta; Facchini, Marcella; Rotili, Dante; Mai, Antonello; Artico, Marino; Armand-Ugón, Mercedes; Esté, José A; Maga, Giovanni

    2008-09-01

    We recently reported the synthesis and biological evaluation of a novel series of 5-alkyl-2-(N,N-disubstituted)amino-6-(2,6-difluorophenylalkyl)-3,4-dihydropyrimidin-4(3H)-ones (F(2)-N,N-DABOs). These compounds are highly active against both wild-type HIV-1 and the K103N, Y181C, and Y188L mutant strains. Herein we present novel 6-(2-chloro-6-fluorophenylalkyl)-N,N-DABO (2-Cl-6-F-N,N-DABO) derivatives and investigate the molecular basis for their high-affinity binding to HIV-1 reverse transcriptase (RT). Our results show that the new compounds display higher association rates than the difluoro derivatives toward wild-type HIV-1 RT or drug-resistant RT mutant forms. We also show that they preferentially associate to either the free enzyme or the enzyme-nucleic acid binary complex, and that this binding is stabilized upon formation of the ternary complex between HIV-1 RT and both the nucleic acid and nucleotide substrates. Interestingly, one compound showed dissociation rates from the ternary complex with RT mutants K103N and Y181I 10-20-fold slower than from the corresponding complex with wild-type RT.

  2. Dinuclear 1,4,7-triazacyclononane (tacn) complexes of cobalt(III) with amido and tacn bridges. Synthesis, characterization and reversible acid-accelerated bridge cleavage

    DEFF Research Database (Denmark)

    Andersen, Peter; Glerup, Jørgen; Gumm, Andreas

    2004-01-01

    -tacn(-H)]Co(NH3)]3+, were isolated as perchlorates, and the crystal structure of the perrhenate of the latter complex was determined by X-ray diffraction. In this compound a nitrogen atom (deprotonated) from one of the tacn ligands forms a third bridge together with two amido bridges. In 1.0 M (Na,H)ClO4 ([H+] 0......)]4+. An isolated perchlorate of this complex appeared to be the salt of the trans-ammineaqua isomer as determined by X-ray diffraction. Equilibration from both sides fits the first-order rate constant dependence k(obs)=6.2(3) x 10(-5)[H+] + 2.1(2) x 10(-5)(s(-1)) at 40 degrees C. Prolonged treatment of the two...

  3. High pH reversed-phase chromatography as a superior fractionation scheme compared to off-gel isoelectric focusing for complex proteome analysis.

    Science.gov (United States)

    Stein, Derek R; Hu, Xiaojie; McCorrister, Stuart J; Westmacott, Garrett R; Plummer, Francis A; Ball, Terry B; Carpenter, Michael S

    2013-10-01

    MS/MS is the technology of choice for analyzing complex protein mixtures. However, due to the intrinsic complexity and dynamic range present in higher eukaryotic proteomes, prefractionation is an important step to maximize the number of proteins identified. Off-gel IEF (OG-IEF) and high pH RP (Hp-RP) column chromatography have both been successfully utilized as a first-dimension peptide separation technique in shotgun proteomic experiments. Here, a direct comparison of the two methodologies was performed on ex vivo peripheral blood mononuclear cell lysate. In 12-fraction replicate analysis, Hp-RP resulted in more peptides and proteins identified than OG-IEF fractionation. Distributions of peptide pIs and hydropathy did not reveal any appreciable bias in either technique. Resolution, defined here as the ability to limit a specific peptide to one particular fraction, was significantly better for Hp-RP. This leads to a more uniform distribution of total and unique peptides for Hp-RP across all fractions collected. These results suggest that fractionation by Hp-RP over OG-IEF is the better choice for typical complex proteome analysis. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Reversible Modification of Adenomatous Polyposis Coli (APC) with K63-linked Polyubiquitin Regulates the Assembly and Activity of the β-Catenin Destruction Complex

    Science.gov (United States)

    Tran, Hoanh; Polakis, Paul

    2012-01-01

    The adenomatous polyposis coli (APC) tumor suppressor forms a complex with Axin and GSK3β to promote the phosphorylation and degradation of β-catenin, a key co-activator of Wnt-induced transcription. Here, we establish that APC is modified predominantly with K63-linked ubiquitin chains when it is bound to Axin in unstimulated HEK293 cells. Wnt3a stimulation induced a time-dependent loss of K63-polyubiquitin adducts from APC, an effect synchronous with the dissociation of Axin from APC and the stabilization of cytosolic β-catenin. RNAi-mediated depletion of Axin or β-catenin, which negated the association between APC and Axin, resulted in the absence of K63-adducts on APC. Overexpression of wild-type and phosphodegron-mutant β-catenin, combined with analysis of thirteen human cancer cell lines that harbor oncogenic mutations in APC, Axin, or β-catenin, support the hypothesis that a fully assembled APC-Axin-GSK3β-phospho-β-catenin complex is necessary for the K63-polyubiquitylation of APC. Intriguingly, the degree of this modification on APC appears to correlate inversely with the levels of β-catenin in cells. Together, our results indicate that K63-linked polyubiquitin adducts on APC regulate the assembly and/or efficiency of the β-catenin destruction complex. PMID:22761442

  5. Computer Program for Calculation of Complex Chemical Equilibrium Compositions, Rocket Performance, Incident and Reflected Shocks, and Chapman-Jouguet Detonations. Interim Revision, March 1976

    Science.gov (United States)

    Gordon, S.; Mcbride, B. J.

    1976-01-01

    A detailed description of the equations and computer program for computations involving chemical equilibria in complex systems is given. A free-energy minimization technique is used. The program permits calculations such as (1) chemical equilibrium for assigned thermodynamic states (T,P), (H,P), (S,P), (T,V), (U,V), or (S,V), (2) theoretical rocket performance for both equilibrium and frozen compositions during expansion, (3) incident and reflected shock properties, and (4) Chapman-Jouguet detonation properties. The program considers condensed species as well as gaseous species.

  6. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, J.L.; Smith, R.D.

    1993-11-30

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

  7. Chemical restraint of captive Kinkajous Potos flavus (Schreber, 1774 (Carnivora: Procyonidae using a ketamine, xylazine and midazolam combination and reversal with yohimbine

    Directory of Open Access Journals (Sweden)

    Jesús Lescano

    2016-12-01

    Full Text Available Detailed information on the anaesthetic and cardiorespiratory effects of drug combinations used for the chemical immobilization of Kinkajous (Potos flavus is scarce.  This study assessed the effects of ketamine (2.5mg/kg, xylazine (1mg/kg and midazolam (0.5mg/kg combination in P. flavus.  Five clinically healthy adult Kinkajous of both sexes were included.  Heart rate, respiratory rate, oxygen saturation, blood pressure and body temperature were recorded at five-minute intervals for 25 minutes.  Then, animals received 0.125mg/kg of yohimbine by intramuscular injection.  Anaesthetic depth was assessed based on stimulus response and muscle tone.  Induction, immobilization, and recovery periods were recorded and qualitatively assessed based on the absence of adverse effects.  The durations of the induction, immobilization, and recovery periods were 9.42±1.73, 33.33±2.16, and 31.37±5.82 minutes.  All periods showed good quality and adequate anaesthetic depth was achieved.  Mean heart and respiratory rates were 99±20 beats/minute and 44±9 breaths/minute.  Both parameters decreased over the duration of the anaesthesia but they did not reach levels suggesting either bradycardia or bradypnea.  Mean body temperature was 37.1±1.5 0C and it also showed a decreasing trend over the duration of the anaesthesia.  Mean oxygen saturation was 92±6% and it showed a mildly increasing trend over the duration of the anesthesia.  Mean blood pressure was 129±23 mmHg and mild to moderate hypertension was observed.  No mortality occurred and no adverse effects were observed in any of the individuals during the three months following immobilization.  The assessed anaesthetic combination effectively immobilized the P. flavus individuals, provided good quality and acceptable duration of both induction and recovery periods.  It should, however, not be used in Kinkajous with either known hypertension record or pre-existing target organ disease (e

  8. Focusing and non-focusing modulation strategies for the improvement of on-line two-dimensional hydrophilic interaction chromatography × reversed phase profiling of complex food samples.

    Science.gov (United States)

    Montero, Lidia; Ibáñez, Elena; Russo, Mariateresa; Rastrelli, Luca; Cifuentes, Alejandro; Herrero, Miguel

    2017-09-08

    Comprehensive two-dimensional liquid chromatography (LC × LC) is ever gaining interest in food analysis, as often, food-related samples are too complex to be analyzed through one-dimensional approaches. The use of hydrophilic interaction chromatography (HILIC) combined with reversed phase (RP) separations has already been demonstrated as a very orthogonal combination, which allows attaining increased resolving power. However, this coupling encompasses different analytical challenges, mainly related to the important solvent strength mismatch between the two dimensions, besides those common to every LC × LC method. In the present contribution, different strategies are proposed and compared to further increase HILIC × RP method performance for the analysis of complex food samples, using licorice as a model sample. The influence of different parameters in non-focusing modulation methods based on sampling loops, as well as under focusing modulation, through the use of trapping columns in the interface and through active modulation procedures are studied in order to produce resolving power and sensitivity gains. Although the use of a dilution strategy using sampling loops as well as the highest possible first dimension sampling rate allowed significant improvements on resolution, focusing modulation produced significant gains also in peak capacity and sensitivity. Overall, the obtained results demonstrate the great applicability and potential that active modulation may have for the analysis of complex food samples, such as licorice, by HILIC × RP. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. The adsorption of 99mTc(Sn)-diphosphonate complexes on tri-calciumphosphate: the influence of preparation conditions, ligand-type, incubation media and adsorption conditions. The reversibility of the adsorption

    International Nuclear Information System (INIS)

    Huigen, Y.M.; Krips, H.J.; Hulleman, S.; Gelsema, W.J.; Ligny, C.L. de

    1990-01-01

    The influence of several variables on the adsorption of 99m Tc(Sn)-diphosphate complexes on tricalciumphosphate was determined. The composition of the incubation medium influenced the percentage adsorption: with Hank's balanced salt solution (a medium frequently used for bone cell cultures) and Tris buffer lower percentage adsorption was obtained than with physiological saline as the incubation medium. The influence of addition to the incubation medium of some ions and natural species, some of which occur in bone fluid, is very specific. Addition of Sn(II) or Mg(II) (a component of HBSS) reduces the amount of adsorption. Addition of Ca(II) and Al(III) had no effect. Addition of sodium-citrate and MDP to the medium and an increase of the pH of the medium decreased the percentage adsorption. The ligand that was used in the preparation of the complex mixture influences the percentage adsorption considerably. The Sn(II) concentration used during the preparation of the 99m Tc(Sn)-MDP and 99m Tc(Sn)-MHDP complexes showed no definite influence on the percentage adsorption. The pH and ligand concentration, used in the preparation, however, did effect the percentage adsorption. It was concluded that the 99m Tc(Sn)-disphosphonate mixtures are part reversibly and part irreversibly bound to tri-calcium-phosphate. (author)

  10. Brain histamine depletion enhances the behavioural sequences complexity of mice tested in the open-field: Partial reversal effect of the dopamine D2/D3 antagonist sulpiride.

    Science.gov (United States)

    Santangelo, Andrea; Provensi, Gustavo; Costa, Alessia; Blandina, Patrizio; Ricca, Valdo; Crescimanno, Giuseppe; Casarrubea, Maurizio; Passani, M Beatrice

    2017-02-01

    Markers of histaminergic dysregulation were found in several neuropsychiatric disorders characterized by repetitive behaviours, thoughts and stereotypies. We analysed the effect of acute histamine depletion by means of i. c.v. injections of alpha-fluoromethylhistidine, a blocker of histidine decarboxylase, on the temporal organization of motor sequences of CD1 mice behaviour in the open-field test. An ethogram encompassing 9 behavioural components was employed. Durations and frequencies were only slightly affected by treatments. However, as revealed by multivariate t-pattern analysis, histamine depletion was associated with a striking increase in the number of behavioural patterns. We found 42 patterns of different composition occurring, on average, 520.90 ± 50.23 times per mouse in the histamine depleted (HD) group, whereas controls showed 12 different patterns occurring on average 223.30 ± 20.64 times. Exploratory and grooming behaviours clustered separately, and the increased pattern complexity involved exclusively exploratory patterns. To test the hypothesis of a histamine-dopamine interplay on behavioural pattern phenotype, non-sedative doses of the D2/D3 antagonist sulpiride (12.5-25-50 mg/kg) were additionally administered to different groups of HD mice. Sulpiride counterbalanced the enhancement of exploratory patterns of different composition, but it did not affect the mean number of patterns at none of the doses used. Our results provide new insights on the role of histamine on repetitive behavioural sequences of freely moving mice. Histamine deficiency is correlated with a general enhancement of pattern complexity. This study supports a putative involvement of histamine in the pathophysiology of tics and related disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Estrogenic Endocrine Disrupting Chemicals Influencing NRF1 Regulated Gene Networks in the Development of Complex Human Brain Diseases.

    Science.gov (United States)

    Preciados, Mark; Yoo, Changwon; Roy, Deodutta

    2016-12-13

    During the development of an individual from a single cell to prenatal stages to adolescence to adulthood and through the complete life span, humans are exposed to countless environmental and stochastic factors, including estrogenic endocrine disrupting chemicals. Brain cells and neural circuits are likely to be influenced by estrogenic endocrine disruptors (EEDs) because they strongly dependent on estrogens. In this review, we discuss both environmental, epidemiological, and experimental evidence on brain health with exposure to oral contraceptives, hormonal therapy, and EEDs such as bisphenol-A (BPA), polychlorinated biphenyls (PCBs), phthalates, and metalloestrogens, such as, arsenic, cadmium, and manganese. Also we discuss the brain health effects associated from exposure to EEDs including the promotion of neurodegeneration, protection against neurodegeneration, and involvement in various neurological deficits; changes in rearing behavior, locomotion, anxiety, learning difficulties, memory issues, and neuronal abnormalities. The effects of EEDs on the brain are varied during the entire life span and far-reaching with many different mechanisms. To understand endocrine disrupting chemicals mechanisms, we use bioinformatics, molecular, and epidemiologic approaches. Through those approaches, we learn how the effects of EEDs on the brain go beyond known mechanism to disrupt the circulatory and neural estrogen function and estrogen-mediated signaling. Effects on EEDs-modified estrogen and nuclear respiratory factor 1 (NRF1) signaling genes with exposure to natural estrogen, pharmacological estrogen-ethinyl estradiol, PCBs, phthalates, BPA, and metalloestrogens are presented here. Bioinformatics analysis of gene-EEDs interactions and brain disease associations identified hundreds of genes that were altered by exposure to estrogen, phthalate, PCBs, BPA or metalloestrogens. Many genes modified by EEDs are common targets of both 17 β-estradiol (E2) and NRF1. Some of

  12. Estrogenic Endocrine Disrupting Chemicals Influencing NRF1 Regulated Gene Networks in the Development of Complex Human Brain Diseases

    Directory of Open Access Journals (Sweden)

    Mark Preciados

    2016-12-01

    Full Text Available During the development of an individual from a single cell to prenatal stages to adolescence to adulthood and through the complete life span, humans are exposed to countless environmental and stochastic factors, including estrogenic endocrine disrupting chemicals. Brain cells and neural circuits are likely to be influenced by estrogenic endocrine disruptors (EEDs because they strongly dependent on estrogens. In this review, we discuss both environmental, epidemiological, and experimental evidence on brain health with exposure to oral contraceptives, hormonal therapy, and EEDs such as bisphenol-A (BPA, polychlorinated biphenyls (PCBs, phthalates, and metalloestrogens, such as, arsenic, cadmium, and manganese. Also we discuss the brain health effects associated from exposure to EEDs including the promotion of neurodegeneration, protection against neurodegeneration, and involvement in various neurological deficits; changes in rearing behavior, locomotion, anxiety, learning difficulties, memory issues, and neuronal abnormalities. The effects of EEDs on the brain are varied during the entire life span and far-reaching with many different mechanisms. To understand endocrine disrupting chemicals mechanisms, we use bioinformatics, molecular, and epidemiologic approaches. Through those approaches, we learn how the effects of EEDs on the brain go beyond known mechanism to disrupt the circulatory and neural estrogen function and estrogen-mediated signaling. Effects on EEDs-modified estrogen and nuclear respiratory factor 1 (NRF1 signaling genes with exposure to natural estrogen, pharmacological estrogen-ethinyl estradiol, PCBs, phthalates, BPA, and metalloestrogens are presented here. Bioinformatics analysis of gene-EEDs interactions and brain disease associations identified hundreds of genes that were altered by exposure to estrogen, phthalate, PCBs, BPA or metalloestrogens. Many genes modified by EEDs are common targets of both 17 β-estradiol (E2 and

  13. Structure, solvent, and relativistic effects on the NMR chemical shifts in square-planar transition-metal complexes: assessment of DFT approaches

    Czech Academy of Sciences Publication Activity Database

    Vícha, J.; Novotný, J.; Straka, Michal; Repisky, M.; Ruud, K.; Komorovsky, S.; Marek, R.

    2015-01-01

    Roč. 17, č. 38 (2015), s. 24944-24955 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GA14-03564S Institutional support: RVO:61388963 Keywords : NMR chemical shifts * transition metal complexes * relativistic effects * method calibration Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.449, year: 2015 http://pubs.rsc.org/en/content/articlepdf/2015/cp/c5cp04214c

  14. Reverse Transfection Using Gold Nanoparticles

    Science.gov (United States)

    Yamada, Shigeru; Fujita, Satoshi; Uchimura, Eiichiro; Miyake, Masato; Miyake, Jun

    Reverse transfection from a solid surface has the potential to deliver genes into various types of cell and tissue more effectively than conventional methods of transfection. We present a method for reverse transfection using a gold colloid (GC) as a nanoscaffold by generating nanoclusters of the DNA/reagentcomplex on a glass surface, which could then be used for the regulation of the particle size of the complex and delivery of DNA into nuclei. With this method, we have found that the conjugation of gold nanoparticles (20 nm in particle size) to the pEGFP-N1/Jet-PEI complex resulted in an increase in the intensity of fluorescence of enhanced green fluorescent protein (EGFP) (based on the efficiency of transfection) from human mesenchymal stem cells (hMSCs), as compared with the control without GC. In this manner, we constructed a method for reverse transfection using GC to deliver genes into the cells effectively.

  15. Energy saving analysis and management modeling based on index decomposition analysis integrated energy saving potential method: Application to complex chemical processes

    International Nuclear Information System (INIS)

    Geng, Zhiqiang; Gao, Huachao; Wang, Yanqing; Han, Yongming; Zhu, Qunxiong

    2017-01-01

    Highlights: • The integrated framework that combines IDA with energy-saving potential method is proposed. • Energy saving analysis and management framework of complex chemical processes is obtained. • This proposed method is efficient in energy optimization and carbon emissions of complex chemical processes. - Abstract: Energy saving and management of complex chemical processes play a crucial role in the sustainable development procedure. In order to analyze the effect of the technology, management level, and production structure having on energy efficiency and energy saving potential, this paper proposed a novel integrated framework that combines index decomposition analysis (IDA) with energy saving potential method. The IDA method can obtain the level of energy activity, energy hierarchy and energy intensity effectively based on data-drive to reflect the impact of energy usage. The energy saving potential method can verify the correctness of the improvement direction proposed by the IDA method. Meanwhile, energy efficiency improvement, energy consumption reduction and energy savings can be visually discovered by the proposed framework. The demonstration analysis of ethylene production has verified the practicality of the proposed method. Moreover, we can obtain the corresponding improvement for the ethylene production based on the demonstration analysis. The energy efficiency index and the energy saving potential of these worst months can be increased by 6.7% and 7.4%, respectively. And the carbon emissions can be reduced by 7.4–8.2%.

  16. An antibody to the GM1/GalNAc-GD1a complex correlates with development of pure motor Guillain-Barré syndrome with reversible conduction failure.

    Science.gov (United States)

    Ogawa, Go; Kaida, Ken-ichi; Kuwahara, Motoi; Kimura, Fumihiko; Kamakura, Keiko; Kusunoki, Susumu

    2013-01-15

    Antibodies to a ganglioside complex consisting of GM1 and GalNAc-GD1a (GM1/GalNAc-GD1a) are found in sera from patients with Guillain-Barré syndrome (GBS). To elucidate the clinical significance of anti-GM1/GalNAc-GD1a antibodies in GBS, clinical features of 58 GBS patients with IgG anti-GM1/GalNAc-GD1a antibodies confirmed by enzyme-linked immunosorbent assay and thin layer chromatography immunostaining were analyzed. Compared to GBS patients without anti-GM1/GalNAc-GD1a antibodies, anti-GM1/GalNAc-GD1a-positive patients more frequently had a preceding respiratory infection (n=38, 66%, pbedridden cases were able to walk independently within one month after the nadir. These results show that the presence of anti-GM1/GalNAc-GD1a antibodies correlated with pure motor GBS characterized by antecedent respiratory infection, fewer cranial nerve deficits, and CBs at intermediate sites of motor nerves. The CB may be generated through alteration of the regulatory function of sodium channels in the nodal axolemma. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Spectrofluorimetric determination of stoichiometry and association constants of the complexes of harmane and harmine with beta-cyclodextrin and chemically modified beta-cyclodextrins.

    Science.gov (United States)

    Martín, L; León, A; Olives, A I; Del Castillo, B; Martín, M A

    2003-06-13

    The association characteristics of the inclusion complexes of the beta-carboline alkaloids harmane and harmine with beta-cyclodextrin (beta-CD) and chemically modified beta-cyclodextrins such as hydroxypropyl-beta-cyclodextrin (HPbeta-CD), 2,3-di-O-methyl-beta-cyclodextrin (DMbeta-CD) and 2,3,6-tri-O-methyl-beta-cyclodextrin (TMbeta-CD) are described. The association constants vary from 112 for harmine/DMbeta-CD to 418 for harmane/HPbeta-CD. The magnitude of the interactions between the host and the guest molecules depends on the chemical and geometrical characteristics of the guest molecules and therefore the association constants vary for the different cyclodextrin complexes. The steric hindrance is higher in the case of harmine due to the presence of methoxy group on the beta-carboline ring. The association obtained for the harmane complexes is stronger than the one observed for harmine complexes except in the case of harmine/TMbeta-CD. Important differences in the association constants were observed depending on the experimental variable used in the calculations (absolute value of fluorescence intensity or the ratio between the fluorescence intensities corresponding to the neutral and cationic forms). When fluorescence intensity values were considered, the association constants were higher than when the ratio of the emission intensity for the cationic and neutral species was used. These differences are a consequence of the co-existence of acid-base equilibria in the ground and in excited states together with the complexation equilibria. The existence of a proton transfer reaction in the excited states of harmane or harmine implies the need for the experimental dialysis procedure for separation of the complexes from free harmane or harmine. Such methodology allows quantitative results for stoichiometry determinations to be obtained, which show the existence of both 1:1 and 1:2 beta-carboline alkaloid:CD complexes with different solubility properties.

  18. Uranium(VI) sorption onto magnetite. Increasing confidence in surface complexation models using chemically evident surface chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Bok, Frank [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes

    2017-06-01

    Surface complexation models have made great efforts in describing the sorption of various radionuclides on naturally occurring mineral phases. Unfortunately, many of the published sorption parameter sets are built upon unrealistic or even wrong surface chemistry. This work describes the benefit of combining spectroscopic and batch sorption experimental data to create a reliable and consistent surface complexation parameter set.

  19. Quantum-chemical, NMR, FT IR, and ESI MS studies of complexes of colchicine with Zn(II).

    Science.gov (United States)

    Jankowski, Wojciech; Kurek, Joanna; Barczyński, Piotr; Hoffmann, Marcin

    2017-04-01

    Colchicine is a tropolone alkaloid from Colchicinum autumnale. It shows antifibrotic, antimitotic, and anti-inflammatory activities, and is used to treat gout and Mediterranean fever. In this work, complexes of colchicine with zinc(II) nitrate were synthesized and investigated using DFT, 1 H and 13 C NMR, FT IR, and ESI MS. The counterpoise-corrected and uncorrected interaction energies of these complexes were calculated. We also calculated their 1 H, 13 C NMR, and IR spectra and compared them with the corresponding experimentally obtained data. According to the ESI MS mass spectra, colchicine forms stable complexes with zinc(II) nitrate that have various stoichiometries: 2:1, 1:1:1, and 2:1:1 with respect to colchichine, Zn(II), and nitrate ion. All of the complexes were investigated using the quantum theory of atoms in molecules (QTAIM). The calculated and the measured spectra showed differences before and after the complexation process. Calculated electron densities and bond critical points indicated the presence of bonds between the ligands and the central cation in the investigated complexes that satisfied the quantum theory of atoms in molecules. Graphical Abstract DFT, NMR, FT IR, ESI MS, QTAIM and puckering studies of complexes of colchicine with Zn(II).

  20. Kinetic Line Voronoi Operations and Their Reversibility

    DEFF Research Database (Denmark)

    Mioc, Darka; Anton, François; Gold, Christopher

    2010-01-01

    In Geographic Information Systems the reversibility of map update operations has not been explored yet. In this paper we are using the Voronoi based Quad-edge data structure to define reversible map update operations. The reversibility of the map operations has been formalised at the lowest level...... mechanisms and dynamic map visualisations. In order to use the reversibility within the kinetic Voronoi diagram of points and open oriented line segments, we need to assure that reversing the map commands will produce exactly the changes in the map equivalent to the previous map states. To prove...... that reversing the map update operations produces the exact reverse changes, we show an isomorphism between the set of complex operations on the kinetic Voronoi diagram of points and open oriented line segments and the sets of numbers of new / deleted Voronoi regions induced by these operations, and its...

  1. Structure-Function, Stability, and Chemical Modification of the Cyanobacterial Cytochrome b6f Complex from Nostoc sp. PCC 7120*

    Science.gov (United States)

    Baniulis, Danas; Yamashita, Eiki; Whitelegge, Julian P.; Zatsman, Anna I.; Hendrich, Michael P.; Hasan, S. Saif; Ryan, Christopher M.; Cramer, William A.

    2009-01-01

    The crystal structure of the cyanobacterial cytochrome b6f complex has previously been solved to 3.0-Å resolution using the thermophilic Mastigocladus laminosus whose genome has not been sequenced. Several unicellular cyanobacteria, whose genomes have been sequenced and are tractable for mutagenesis, do not yield b6f complex in an intact dimeric state with significant electron transport activity. The genome of Nostoc sp. PCC 7120 has been sequenced and is closer phylogenetically to M. laminosus than are unicellular cyanobacteria. The amino acid sequences of the large core subunits and four small peripheral subunits of Nostoc are 88 and 80% identical to those in the M. laminosus b6f complex. Purified b6f complex from Nostoc has a stable dimeric structure, eight subunits with masses similar to those of M. laminosus, and comparable electron transport activity. The crystal structure of the native b6f complex, determined to a resolution of 3.0Å (PDB id: 2ZT9), is almost identical to that of M. laminosus. Two unique aspects of the Nostoc complex are: (i) a dominant conformation of heme bp that is rotated 180° about the α- and γ-meso carbon axis relative to the orientation in the M. laminosus complex and (ii) acetylation of the Rieske iron-sulfur protein (PetC) at the N terminus, a post-translational modification unprecedented in cyanobacterial membrane and electron transport proteins, and in polypeptides of cytochrome bc complexes from any source. The high spin electronic character of the unique heme cn is similar to that previously found in the b6f complex from other sources. PMID:19189962

  2. Use of reversed-phase gel partition chromatography for the purification of chemically synthesized (5,6,8,9,11,12,14,15(n)) octadeuterium- and octatritium-labelled arachidonic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wollard, P M; Lascelles, P T [Department of Chemical Pathology, Institute of Neurology, London, Great Britain; Hensby, C N [Hammersmith Hospital, London (UK). Postgraduate Medical School

    1978-12-11

    The development of a method is described for the preparation and purification of (5,6,8,9,11,12,14,15(n)-/sup 2/H)arachidonic acid (/sup 2/H/sub 8/-AA). The /sup 2/H/sub 8/-AA was chemically synthesised by the selective reduction of 5,8,11,14-eiconsatetraynoic acid (ETYA) with deuterium gas. Using reversed-phase partition chromatography on a Lipidex 5000 column support, it was shown that: (1) The reaction products could readily be separated from each other to yield /sup 2/H/sub 8/-AA of greater than 98% mass purity by gas chromatography. (2) Closely related C20 cis-ethylenic fatty acids differing only in the degree of unsaturation are efficiently separated. The resolution increases exponentially on saturation of double bonds. (3) Commercially available (5,6,8,9,11,12,14,15(n))octatritium-labelled arachidonic acid (/sup 3/H/sub 8/-AA) was readily purified. Both (/sup 3/H/sub 8/)- and (1-/sup 14/C)arachidonic acid (/sup 14/C-AA) co-chromatographed with /sup 2/H/sub 8/-AA. (4) The mass spectra of the methyl ester and trimethylsilyl ester of the purified /sup 2/H/sub 8/-AA showed molecular ions at m/e 326 and 384, respectively.

  3. Host–guest complexes of mixed glycol-bipyridine cryptands: prediction of ion selectivity by quantum chemical calculations, part V

    Directory of Open Access Journals (Sweden)

    Svetlana Begel

    2013-06-01

    Full Text Available The selectivity of the cryptands [2.2.bpy] and [2.bpy.bpy] for the endohedral complexation of alkali, alkaline-earth and earth metal ions was predicted on the basis of the DFT (B3LYP/LANL2DZp calculated structures and complex-formation energies. The cavity size in both cryptands lay between that for [2.2.2] and [bpy.bpy.bpy], such that the complexation of K+, Sr2+ and Tl3+ is most favorable. While the [2.2.bpy] is moderately larger, preferring Rb+ complexation and demonstrating equal priority for Sr2+ and Ba2+, the slightly smaller [2.bpy.bpy] yields more stable cryptates with Na+ and Ca2+. Although the CH2-units containing molecular bars fixed at the bridgehead nitrogen atoms determine the flexibility of the cryptands, the twist angles associated with the bipyridine and glycol building blocks also contribute considerably.

  4. Modelling of retention of pesticides in reversed-phase high-performance liquid chromatography: Quantitative structure-retention relationships based on solute quantum-chemical descriptors and experimental (solvatochromic and spin-probe) mobile phase descriptors

    International Nuclear Information System (INIS)

    D'Archivio, Angelo Antonio; Ruggieri, Fabrizio; Mazzeo, Pietro; Tettamanti, Enzo

    2007-01-01

    A quantitative structure-retention relationship (QSRR) analysis based on multilinear regression (MLR) and artificial neural networks (ANNs) is carried out to model the combined effect of solute structure and eluent composition on the retention behaviour of pesticides in isocratic reversed-phase high-performance liquid chromatography (RP-HPLC). The octanol-water partition coefficient and four quantum chemical descriptors (the total dipole moment, the mean polarizability, the anisotropy of the polarizability and a descriptor of hydrogen-bonding based on the atomic charges on acidic and basic chemical functionalities) are considered as solute descriptors. In order to identify suitable mobile phase descriptors, encoding composition-dependent properties of both methanol- and acetonitrile-containing mobile phases, the Kamlet-Taft solvatochromic parameters (polarity-dipolarity, hydrogen-bond acidity and hydrogen-bond basicity, π * , α and β, respectively) and the 14 N hyperfine-splitting constant (a N ) of a spin-probe dissolved in the eluent are examined. A satisfactory description of mobile phase properties influencing the solute retention is provided by a N and β or alternatively π * and β. The two seven-parameter models resulting from combination of a N and β, or π * and β, with the solute descriptors were tested on a set of 26 pesticides representative of 10 different chemical classes in a wide range of mobile phase composition (30-60% (v/v) water-methanol and 30-70% (v/v) water-acetonitrile). Within the explored experimental range, the acidity of the eluent, as quantified by α, is almost constant, and this parameter is in fact irrelevant. The results reveal that a N and π * , that can be considered as interchangeable mobile phase descriptors, are the most influent variables in the respective models. The predictive ability of the proposed models, as tested on an external data set, is quite good (Q 2 close to 0.94) when a MLR approach is used, but the

  5. Modelling of retention of pesticides in reversed-phase high-performance liquid chromatography: Quantitative structure-retention relationships based on solute quantum-chemical descriptors and experimental (solvatochromic and spin-probe) mobile phase descriptors

    Energy Technology Data Exchange (ETDEWEB)

    D' Archivio, Angelo Antonio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy)]. E-mail: darchivi@univaq.it; Ruggieri, Fabrizio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); Mazzeo, Pietro [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); Tettamanti, Enzo [Dipartimento di Scienze Biomediche Comparate, Universita di Teramo, P.zzale A. Moro 45, 64100 Teramo (Italy)

    2007-06-19

    A quantitative structure-retention relationship (QSRR) analysis based on multilinear regression (MLR) and artificial neural networks (ANNs) is carried out to model the combined effect of solute structure and eluent composition on the retention behaviour of pesticides in isocratic reversed-phase high-performance liquid chromatography (RP-HPLC). The octanol-water partition coefficient and four quantum chemical descriptors (the total dipole moment, the mean polarizability, the anisotropy of the polarizability and a descriptor of hydrogen-bonding based on the atomic charges on acidic and basic chemical functionalities) are considered as solute descriptors. In order to identify suitable mobile phase descriptors, encoding composition-dependent properties of both methanol- and acetonitrile-containing mobile phases, the Kamlet-Taft solvatochromic parameters (polarity-dipolarity, hydrogen-bond acidity and hydrogen-bond basicity, {pi} {sup *}, {alpha} and {beta}, respectively) and the {sup 14}N hyperfine-splitting constant (a {sub N}) of a spin-probe dissolved in the eluent are examined. A satisfactory description of mobile phase properties influencing the solute retention is provided by a {sub N} and {beta} or alternatively {pi} {sup *} and {beta}. The two seven-parameter models resulting from combination of a {sub N} and {beta}, or {pi} {sup *} and {beta}, with the solute descriptors were tested on a set of 26 pesticides representative of 10 different chemical classes in a wide range of mobile phase composition (30-60% (v/v) water-methanol and 30-70% (v/v) water-acetonitrile). Within the explored experimental range, the acidity of the eluent, as quantified by {alpha}, is almost constant, and this parameter is in fact irrelevant. The results reveal that a {sub N} and {pi} {sup *}, that can be considered as interchangeable mobile phase descriptors, are the most influent variables in the respective models. The predictive ability of the proposed models, as tested on an

  6. Complex chemistry

    International Nuclear Information System (INIS)

    Kim, Bong Gon; Kim, Jae Sang; Kim, Jin Eun; Lee, Boo Yeon

    2006-06-01

    This book introduces complex chemistry with ten chapters, which include development of complex chemistry on history coordination theory and Warner's coordination theory and new development of complex chemistry, nomenclature on complex with conception and define, chemical formula on coordination compound, symbol of stereochemistry, stereo structure and isomerism, electron structure and bond theory on complex, structure of complex like NMR and XAFS, balance and reaction on solution, an organo-metallic chemistry, biology inorganic chemistry, material chemistry of complex, design of complex and calculation chemistry.

  7. Synthesis, physico-chemical and antimicrobial screening studies on 14 and 16-membered hexaazamacrocyclic complexes bearing pendant amine groups

    Directory of Open Access Journals (Sweden)

    Shakir Mohammad

    2006-01-01

    Full Text Available The synthesis and characterization of a series of 14 and 16-membered hexaazamacrocyclic complexes, which were obtained via template condensation of 1,2- diaminoethane or 1,3-diaminopropane, formaldehyde and hydrazine hydrate in the presence of first row transition metal salts are reported. Complexes of the types, [ML¹(NO32]; [CuL¹](NO32 and [ML²Cl2]; [CuL²]Cl2 (where M = Co(II, Ni(II and Zn(II, were obtained. Elemental analyses, IR spectra, ¹H NMR, EPR, UV-Vis, magnetic susceptibility and conductivity measurements have ascertained the overall geometry and stereochemistry of the complexes. An octahedral geometry has been suggested for all the complexes, except for copper compounds, in which the metal centre coordinates to the four nitrogen atoms of macrocyclic ligand in a square planar fashion. These complexes were screened against different fungi and bacteria in vitro and were found to be potentially active in the concentration 5 mg mL-1.

  8. Managing Reverse Logistics or Reversing Logistics Management?

    OpenAIRE

    Brito, Marisa

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse logistics. The thesis brings insights on reverse logistics decision-making and it lays down theoretical principles for reverse logistics as a research field.In particular it puts together a framework ...

  9. Theoretical description of copper Cu(I)/Cu(II) complexes in mixed ammine-aqua environment. DFT and ab initio quantum chemical study

    International Nuclear Information System (INIS)

    Pavelka, Matej; Burda, Jaroslav V.

    2005-01-01

    This work is devoted to investigate the interactions of the Cu(I)/Cu(II) cation with variable ammonia-water ligand field by the quantum chemical approach. For that purpose, the optimization of the [Cu(NH 3 ) m (H 2 O) n ] 2+/+ complexes (where n varies from 0 to 4 or 6 and m + n = 4 or 6) has been performed at the DFT/6-31+G(d) level of theory in conjunction with the B3PW91 hybrid functional. Based on the results of the single-point B3LYP/6-311++G(2df,2pd) calculations, the stabilization energies were determined. The two-coordinated copper(I) complexes appeared to be the most stable compounds with the remaining water or ammonia molecules in the second solvation shell. In the case of the Cu(II) systems, four-coordinated complexes were found to be the most stable. In order to examine and explain bonding characteristics, Morokuma interaction energy decomposition (for selected Cu + complexes) and Natural Population Analysis for all systems were performed. It was found that the most stable structures correlate with the highest donation effects. Therefore, more polarizable ammonia molecules exhibit higher donation than water and thus make stronger bonds to copper. This can be demonstrated by the fact that the NH 3 molecule always tries to occupy the first solvation shell in mixed ammine-aqua complexes

  10. Chemical functionalization of crystalline silicon surface with complexes of type (M3 (Dpa) 4X2) for the development of electronic devices

    International Nuclear Information System (INIS)

    Sanchez Zamora, Maria Alejandra

    2012-01-01

    New surfaces on crystalline silicon (100) diamines have been developed. The diamines 4-aminopyridine, 4-aminomethylpyridine and 1,12-dodecildiame, and self-assembled surfaces Si-diamine-metallic complexes, with cooper (II) acetate and trimetal Cu 3 (dpa) 4 CI 2 were studied. These surfaces are characterized with X-ray photoelectron spectroscopy (XPS), chemical force microscopy (CFM), by contact angle and cyclic voltammetry (CV). The XPS has suggested the formation of diamines monolayers with covalent binding to crystalline silicon, and modification of these surfaces, with metal complexes by coordination chemistry. The CFM has confirmed that surfaces are modified with diamines and cooper (II) acetate, and that were determined different chemical forces according to the change. The contact angle has been suggested that the functionalized surface with 4-aminomethylpyridine has had similar basicity to 1,12-dodecildiame, and more than 4-aminopyridine. This implies that the coordination with metallics complexes is benefited with 4-aminopyridine, which in turn is reflected with electrochemical data. Cyclic voltammetry analysis have showed that silicon surfaces with 4-aminomethylpyridine and 4-aminopyridine with cooper (II) acetate and trimetal have been electrochemically active. Thus, the surfaces could to have interesting applications in molecular electronics. (author) [es

  11. Quantum chemical calculations and spectroscopic measurements of spectroscopic and thermodynamic properties of given uranyl complexes in aqueous solutions with possible environmental and industrial applications

    Directory of Open Access Journals (Sweden)

    Višňak Jakub

    2016-01-01

    Full Text Available A brief introduction into computational methodology and preliminary results for spectroscopic (excitation energies, vibrational frequencies in ground and excited electronic states and thermodynamic (stability constants, standard enthalpies and entropies of complexation reactions properties of some 1:1, 1:2 and 1:3 uranyl sulphato- and selenato- complexes in aqueos solutions will be given. The relativistic effects are included via Effective Core Potential (ECP, electron correlation via (TDDFT/B3LYP (dispersion interaction corrected and solvation is described via explicit inclusion of one hydration sphere beyond the coordinated water molecules. We acknowledge limits of this approximate description – more accurate calculations (ranging from semi-phenomenological two-component spin-orbit coupling up to four-component Dirac-Coulomb-Breit hamiltonian and Molecular Dynamics simulations are in preparation. The computational results are compared with the experimental results from Time-resolved Laser-induced Fluorescence Spectroscopy (TRLFS and UV-VIS spectroscopic studies (including our original experimental research on this topic. In case of the TRLFS and UV-VIS speciation studies, the problem of complex solution spectra decomposition into individual components is ill-conditioned and hints from theoretical chemistry could be very important. Qualitative agreement between our quantum chemical calculations of the spectroscopic properties and experimental data was achieved. Possible applications for geochemical modelling (e.g. safety studies of nuclear waste repositories, modelling of a future mining site and analytical chemical studies (including natural samples are discussed.

  12. The Navy/NASA Engine Program (NNEP89): Interfacing the program for the calculation of complex Chemical Equilibrium Compositions (CEC)

    Science.gov (United States)

    Gordon, Sanford

    1991-01-01

    The NNEP is a general computer program for calculating aircraft engine performance. NNEP has been used extensively to calculate the design and off-design (matched) performance of a broad range of turbine engines, ranging from subsonic turboprops to variable cycle engines for supersonic transports. Recently, however, there has been increased interest in applications for which NNEP is not capable of simulating, such as the use of alternate fuels including cryogenic fuels and the inclusion of chemical dissociation effects at high temperatures. To overcome these limitations, NNEP was extended by including a general chemical equilibrium method. This permits consideration of any propellant system and the calculation of performance with dissociation effects. The new extended program is referred to as NNEP89.

  13. Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces

    International Nuclear Information System (INIS)

    Wilmsmeyer, Amanda R.; Morris, John R.; Gordon, Wesley O.; Mantooth, Brent A.; Lalain, Teri A.; Davis, Erin Durke

    2014-01-01

    A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications

  14. Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces.

    Science.gov (United States)

    Wilmsmeyer, Amanda R; Gordon, Wesley O; Davis, Erin Durke; Mantooth, Brent A; Lalain, Teri A; Morris, John R

    2014-01-01

    A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications.

  15. Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wilmsmeyer, Amanda R.; Morris, John R. [Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061 (United States); Gordon, Wesley O.; Mantooth, Brent A.; Lalain, Teri A. [Research and Technology Directorate, U.S. Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, Maryland 21010 (United States); Davis, Erin Durke [OptiMetrics, Inc., Abingdon, Maryland 21009 (United States)

    2014-01-15

    A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications.

  16. Chemical imaging techniques for the analysis of complex mixtures: New application to the characterization of ritual matters on African wooden statuettes

    International Nuclear Information System (INIS)

    Mazel, Vincent; Richardin, Pascale; Touboul, David; Brunelle, Alain; Walter, Philippe; Laprevote, Olivier

    2006-01-01

    Chemical imaging techniques, based on the combination of microscopy and spectroscopy, are well suited to study both the composition and the spatial organization of heterogeneous complex mixtures of organic and mineral matter. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), followed by scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX) and Fourier transform infrared microscopy (FTIR microscopy) have been applied to non-destructive analysis of micro-samplings of ritual matters deposited on the surface of African wooden statuettes. With a very careful preparation, using ultramicrotomy on embedded samples, it was possible to perform successively all the measurements on a single fragment. Comparison and superposition of the different chemical images, obtained on a sample from a significant actual artefact, have allowed us to identify minerals (clays, quartz and calcium carbonate), proteins, starch, urate salts and lipids and to map their spatial distribution

  17. Plant-beneficial elements status assessment in soil-plant system in the vicinity of a chemical industry complex: shedding light on forage grass safety issues.

    Science.gov (United States)

    Anjum, Naser A; Duarte, Armando C; Pereira, Eduarda; Ahmad, Iqbal

    2015-02-01

    Human health is closely linked with soils via plants, grazers, or plant-based products. This study estimated plant-beneficial elements (macronutrients: K, P; secondary macronutrients: Ca, Mg; micronutrients: Mo, Mn, Na, Ni, Se) in both soils and shoots of two forage grass species (Eriophorum angustifolium and Lolium perenne) prevalent in the vicinity of a chemical industry complex (Estarreja, Portugal). Both soils and plants from the chemical industrial areas exhibited differential concentrations of the studied elements. In soils, the role of contamination was evidenced as insignificant in context of its impact on all the tested macro and secondary macronutrients except P, and micronutrients such as Mo and Ni. In forage grass plant shoots, the role of contamination was evidenced as insignificant in relation to its impact on all the tested macro and secondary macronutrients except K. Between the two forage grass plants, high Se-harboring L. perenne cannot be recommended for its use as animal feed.

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

    Science.gov (United States)

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

    2012-03-01

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

  19. Differential perturbed angular correlation: use of physico-chemical study of some hafnium complexes derivates of hydroxy acids and EDTA

    International Nuclear Information System (INIS)

    Silveira, J.G. da.

    1981-01-01

    Measures of quadrupolar interaction to nucleus level of the metal, in some hafnium complexes are presented, including the analysis by combustion, microanalysis, infrared spectroscopy and thermogravimetry. The hyperfine interaction parameters, the temperature effects and the thermal neutrons capture effects over the irradiated Hf Y (Y = EDTA) are also studied. (author)

  20. Simultaneous mass transfer of H2S and CO2 with complex chemical reactions in an aqueous di-isopropanolamine solution = Gleichzeitige absorption von H2S und CO2 in Wässriger Di-isopropanolaminlösung

    NARCIS (Netherlands)

    Blauwhoff, P.M.M.; van Swaaij, Willibrordus Petrus Maria

    1985-01-01

    The absorption of H2S and CO2 into an aqueous di-isopropanolamine (DIPA) solution was studied experimentally and theoretically as an example of simultaneous mass transfer with complex reversible reactions. The absorption phenomena were classified into three regimes: (1) negligible mutual interaction

  1. Synthesis and Study of Chemical and Photo-physical Properties of Quinolinate Aluminum and Zinc Complexes in Organic Light Emitting Diodes (OLEDs)

    Science.gov (United States)

    Rawat, Madhu; Prakash, Sattey; Singh, C.; Anand, R. S.

    2011-10-01

    Two well known electroluminescent (EL) compounds, aluminum and zinc metallo-8-hydroxyquinolates have been synthesized. Their chemical and physical properties like NMR, FTIR, Cyclic Voltammetry, absorption and EL are studied. Organic LEDs are fabricated using both the material as emissive layers. Electroluminescence spectra of the complexes are measured. 2Alq3 and Znq2 give peak emission in yellow-green region at wavelengths 527nm and 540nm respectively. Znq2 is slightly red shifted compared to Alq3 because metal to ligand charge transfer is more in Znq2. A study of ON voltage, luminance efficiency and stability of OLEDs using both materials is made.

  2. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse

  3. First example of a reversible single-crystal-to-single-crystal polymerization-depolymerization accompanied by a magnetic anomaly for a transition-metal complex with an organic radical.

    Science.gov (United States)

    Ovcharenko, Victor I; Fokin, Sergey V; Kostina, Elvina T; Romanenko, Galina V; Bogomyakov, Artem S; Tretyakov, Eugene V

    2012-11-19

    The reaction of copper(II) hexafluoroacetylacetonate [Cu(hfac)2] with the stable nitronyl nitroxide 2-(1-ethyl-3-methyl-1H-pyrazol-4-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (L(a)) resulted in a paired heterospin complex [[Cu(hfac)2]3(μ-O,N-L(a))2][Cu(hfac)2(O-L(a))2]. The crystals of the compound were found to be capable of a reversible single-crystal-to-single-crystal (SC-SC) transformation initiated by the variation of temperature. At room temperature, the molecular structure of [[Cu(hfac)2]3(μ-O,N-L(a))2][Cu(hfac)2(O-L(a))2] is formed by the alternating fragments of the pair complex. Cooling the crystals of the complex below 225 K caused considerable mutual displacements of adjacent molecules, which ended in a transformation of the molecular structure into a polymer chain structure. A reversible topotactic polymerization-depolymerization coordination reaction actually takes place in the solid during repeated cooling-heating cycles: [[Cu(hfac)2]3(μ-O,N-L(a))2][Cu(hfac)2(O-L(a))2] ⇌ Cu(hfac)2(μ-O,N-L(a))]∞. Polymerization during cooling is the result of the anomalously great shortening of intermolecular distances (from 4.403 Å at 295 K to 2.460 Å at 150 K; Δd = 1.943 Å) between the terminal Cu atoms of the trinuclear fragments {[[Cu(hfac)2]3(μ-O,N-L(a))2]} and the noncoordinated N atoms of the pyrazole rings of the mononuclear {[Cu(hfac)2(O-L(a))2]} fragments. When the low-temperature phase was heated above 270 K, the polymer chain structure was destroyed and the compound was again converted to the pair molecular complex. The specifics of the given SC-SC transformation lies in the fact that the process is accompanied by a magnetic anomaly, because the intracrystalline displacements of molecules lead to a considerable change in the mutual orientation of the paramagnetic centers, which, in turn, causes modulation of the exchange interaction between the odd electrons of the Cu(2+) ion and nitroxide. On the temperature curve of

  4. Probing the reactivity of nucleophile residues in human 2,3-diphosphoglycerate/deoxy-hemoglobin complex by aspecific chemical modifications.

    Science.gov (United States)

    Scaloni, A; Ferranti, P; De Simone, G; Mamone, G; Sannolo, N; Malorni, A

    1999-06-11

    The use of aspecific methylation reaction in combination with MS procedures has been employed for the characterization of the nucleophilic residues present on the molecular surface of the human 2,3-diphosphoglycerate/deoxy-hemoglobin complex. In particular, direct molecular weight determinations by ESMS allowed to control the reaction conditions, limiting the number of methyl groups introduced in the modified globin chains. A combined LCESMS-Edman degradation approach for the analysis of the tryptic peptide mixtures yielded to the exact identification of methylation sites together with the quantitative estimation of their degree of modification. The reactivities observed were directly correlated with the pKa and the relative surface accessibility of the nucleophilic residues, calculated from the X-ray crystallographic structure of the protein. The results here described indicate that this methodology can be efficiently used in aspecific modification experiments directed to the molecular characterization of the surface topology in proteins and protein complexes.

  5. Preparation and physico-chemical characterization of inclusion complexes between local anesthetics and hydroxypropyl-β-cyclodextrin

    International Nuclear Information System (INIS)

    Moraes, Carolina Morales; Abrami, Priscila; Goncalves, Marcos Moises; Andreo Filho, Newton; Fernandes, Sergio Antonio; Paula, Eneida de; Fraceto, Leonardo Fernandes

    2007-01-01

    S(-) Bupivacaine (S(-)BVC) and Lidocaine (LDC) are widely used local anesthetics (LA). Hydroxypropyl β-cyclodextrin (HP-β-CD) is used as a drug-carrier system. The aim of this work was to characterize inclusion complexes between LA and HP-β-CD. The affinity constants determined at different pHs show favourable complexation. The release kinetics experiments showed that S(-)BVC and LDC changed the released profiles in the presence of HP-β-CD. Nuclear magnetic resonance experiments gave information about the interaction between LA and the cyclodextrin cavity. This study focused on the physicochemical characterization of drug-delivery formulations that come out as potentially new therapeutic options for pain treatment. (author)

  6. Chemical genetics analysis of an aniline mustard anticancer agent reveals complex I of the electron transport chain as a target.

    Science.gov (United States)

    Fedeles, Bogdan I; Zhu, Angela Y; Young, Kellie S; Hillier, Shawn M; Proffitt, Kyle D; Essigmann, John M; Croy, Robert G

    2011-09-30

    The antitumor agent 11β (CAS 865070-37-7), consisting of a DNA-damaging aniline mustard linked to an androgen receptor (AR) ligand, is known to form covalent DNA adducts and to induce apoptosis potently in AR-positive prostate cancer cells in vitro; it also strongly prevents growth of LNCaP xenografts in mice. The present study describes the unexpectedly strong activity of 11β against the AR-negative HeLa cells, both in cell culture and tumor xenografts, and uncovers a new mechanism of action that likely explains this activity. Cellular fractionation experiments indicated that mitochondria are the major intracellular sink for 11β; flow cytometry studies showed that 11β exposure rapidly induced oxidative stress, mitochondria being an important source of reactive oxygen species (ROS). Additionally, 11β inhibited oxygen consumption both in intact HeLa cells and in isolated mitochondria. Specifically, 11β blocked uncoupled oxygen consumption when mitochondria were incubated with complex I substrates, but it had no effect on oxygen consumption driven by substrates acting downstream of complex I in the mitochondrial electron transport chain. Moreover, 11β enhanced ROS generation in isolated mitochondria, suggesting that complex I inhibition is responsible for ROS production. At the cellular level, the presence of antioxidants (N-acetylcysteine or vitamin E) significantly reduced the toxicity of 11β, implicating ROS production as an important contributor to cytotoxicity. Collectively, our findings establish complex I inhibition and ROS generation as a new mechanism of action for 11β, which supplements conventional DNA adduct formation to promote cancer cell death.

  7. Chemical structure of the complex pyruvylated and sulfated agaran from the red seaweed Palisada flagellifera (Ceramiales, Rhodophyta).

    Science.gov (United States)

    Ferreira, Luciana G; Noseda, Miguel D; Gonçalves, Alan G; Ducatti, Diogo R B; Fujii, Mutue T; Duarte, Maria E R

    2012-01-10

    A homogeneous agaran fraction from Palisada flagellifera (Laurencia complex, Rhodomelaceae, Ceramiales) was obtained by aqueous room-temperature extraction, followed by ion-exchange chromatography. This galactan presents a highly complex structure with at least 18 different types of derivatives. The A units were found mostly pyruvylated, 2-sulfated (∼34%), and 6-methylated (∼34%), with the latter partially 2- and 2,4-sulfated. Minor amounts of β-D-galactopyranosyl units 2-, 6- and 2,6-sulfated, 6-glycosylated, and non-substituted are also present. The B-units are L-sugars composed predominantly of their cyclized derivatives, 3,6-anhydrogalactose and 3,6-anhydro-2-O-methylgalactose (∼56%). The former are linked to β-D-galactosyl (6-methyl) (6-glycosylated) units, as well as to 4,6-O-(1-carboxyethylidene)-β-D-galactose 2-sulfate in the proportion of 3:1.8, respectively. A significant amount (∼18%) of the α-L-galactopyranosyl units are linked to pyruvylated β-D-galactose 2-sulfate residues. An important part of the B-units (20%) is represented by α-L-galactose 6-sulfate substituted on C-3 by xylosyl, galactosyl and/or 2,3-di-O-methylgalactose units or sulfate groups that preclude their cyclization to 3,6-anhydrogalactosyl derivative. The precursor units are present in relatively low percentages. Kinetic studies suggest that in P. flagellifera agaran the cyclizable units are linked to 6-O-methyl-β-D-galactosyl and/or β-D-galactosyl units (6-glycosylated). The structural complexity of this polysaccharide is increased by the presence of 2- and 3,6-sulfated α-L-galactoses, with the latter additionally 2-O-methylated. Therefore, the major subfraction obtained from the cold extract contains structurally complex sulfated, methylated, and pyruvylated agaran. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Application of infrared spectroscopy for study of chemical bonds in complexes of rare earth nitrates with alkylammonium nitrates

    International Nuclear Information System (INIS)

    Klimov, V.D.; Chudinov, Eh.G.

    1974-01-01

    The IR absorption spectra for the tri-n-octylamine, methyl-di-n-octylamine, their nitrates and complexes with the rare element nitrates are obtained. The IR spectra analysis of the complexes has suggested that the degree of covalent character bond of a nitrate with a metal grows with the atomic number of the element. Based on the comparison of the obtained data with those available in literature for various rare-earth complexes a conclusion is made that the bond character of a metal with nitrate groups is influenced by all ligands constituting the inner coordinating sphere. As the donor capacity of a ligand grows the covalent character of the metal-nitrate bond is enhanced. The replacement of the outer-sphere cations (trioctylammonium or methyldioctylammonium) only slightly affects the bond character of a metal with the nitrate group. The distribution coefficients in the rare-earth series are shown to decrease as the electrostatic part in the metal-nitrate declines. The phenomenon is attributed to the competition between nitrate and water for the metal bond as concurrently with the intensification of metal-nitrate covalent bond in the organic phase the strength of metal hydrates in aqueous phase grows much faster. (author)

  9. Isotopic shifts in chemical exchange systems. 1. Large isotope effects in the complexation of Na+ isotopes by macrocyclic polyethers

    International Nuclear Information System (INIS)

    Knoechel, A.; Wilken, R.D.

    1981-01-01

    The complexation of 24 Na + and 22 Na + by 18 of the most widely used macrocyclic polyethers (crown ethers and monocyclic and bicyclic aminopolyethers) has been investigated in view of possible equilibrium isotope shifts. Solvated salts and polyether complexes were distributed differently into two phases and isotope ratios determined in both phases. Chloroform/water systems were shown to be particularly suitable to the investigations allowing favorable distribution for Na + and 13 of the 18 polyethers employed. With crown ethers 24 Na + enrichment varied from nonsignficant values (for large crown ethers) up to 3.1 +- 0.4% (18-crown-6). In the case of bicyclic aminopolyethers, ligands with cages of optimum size to accommodate Na + showed 24 Na + enrichment between O (nonsignificant) (2.2/sub B/2./sub B/) and 5.2 +- 1.8% (2.2.1). In contrast, for 2.2.2. and its derivatives, being too large for Na + , 22 Na + enrichment varying from O (nonsignificant) (2.2.2.p) up to 5.4 +- 0.5% (2.2.2.) has been observed. These values are remarkably high. They are explained by different bonding in solvate structure and polyether complex by using the theoretical approach of Bigeleisen

  10. Synthesis, chemical and biological studies on new Fe(3+)-glycosilated beta-diketo complexes for the treatment of iron deficiency.

    Science.gov (United States)

    Arezzini, Beatrice; Ferrali, Marco; Ferrari, Erika; Frassineti, Chiara; Lazzari, Sandra; Marverti, Gaetano; Spagnolo, Ferdinando; Saladini, Monica

    2008-11-01

    A simple synthetic pathway to obtain glycosilated beta-diketo derivatives is proposed. These compounds show a good iron(III) affinity therefore we may suggest the use of their Fe(3+)-complexes as oral iron supplements in the treatment of anaemia. The glycosilated compounds (6-GlcH, 6-GlcOH and 6-GlcOCH(3)) are characterized by means of spectroscopic (UV, (1)H and (13)C NMR) and potentiometric techniques; they have a good water solubility, are kinetically stable in physiological condition (t(1/2)>100h) and show a low cytotoxicity also in high concentrations (IC(50)>400 microM). They are able to bind Fe(3+) ion in acid condition (pH approximately 2) forming complex species thermodynamically more stable than those of other ligands commonly used in the treatment of iron deficiency. The iron complexes show also a good kinetic stability both in acidic and physiological pH and have a good lypophilicity (logP>-0.7) that suggests an efficient gastrointestinal absorption in view of their possible use in oral therapy. In addition they demonstrate a poor affinity for competitive biological metal ion such as Ca(2+), and in particular 6-GlcOCH(3) is able to inhibit lipid peroxidation.

  11. Host-guest complex of N-(2-chloroethyl), N-nitroso, N‧, N‧ -dicyclohexylsulfamid with β-cyclodextrin: Fluorescence, QTAIM analysis and structure-chemical reactivity

    Science.gov (United States)

    Bensouilah, Nadjia; Fisli, Hassina; Bensouilah, Hamza; Zaater, Sihem; Abdaoui, Mohamed; Boutemeur-Kheddis, Baya

    2017-10-01

    In this work, the inclusion complex of DCY/CENS: N-(2-chloroethyl), N-nitroso, N‧, N‧-dicyclohexylsulfamid and β-cyclodextrin (β-CD) is investigated using the fluorescence spectroscopy, PM3, ONIOM2 and DFT methods. The experimental part reveals that DCY/CENS forms a 1:1 stoichiometric ratio inclusion complex with β-CD. The constant of stability is evaluated using the Benesi-Hildebrand equation. The results of the theoretical optimization showed that the lipophilic fraction of molecule (cyclohexyl group) is inside of β-CD. Accordingly, the Nitroso-Chloroethyl moiety is situated outside the cavity of the macromolecule host. The favorable structure of the optimized complex indicates the existence of weak intermolecular hydrogen bonds and the most important van der Waals (vdW) interactions which are studied on the basis of Natural Bonding Orbital (NBO) analysis. The NBO is employed to compute the electronic donor-acceptor exchanges between drug and β-CD. Furthermore, a detailed topological charge density analysis based on the quantum theory of atoms in molecules (QTAIM), has been accomplished on the most favorable complex using B3LYP/6-31G(d) method. The presence of stabilizing intermolecular hydrogen bonds and van der Waals interactions in the most favorable complex is predicted. Also, the energies of these interactions are estimated with Espinosa's formula. The findings of this investigation reveal that the correlation between the structural parameters and the electronic density is good. Finally, and based on DFT calculations, the reactivity of the interesting molecule in free state was studied and compared with that in the complexed state using chemical potential, global hardness, global softness, electronegativity, electrophilicity and local reactivity descriptors.

  12. Application of high performance liquid chromatography for the profiling of complex chemical mixtures with the aid of chemometrics.

    Science.gov (United States)

    Ni, Yongnian; Zhang, Liangsheng; Churchill, Jane; Kokot, Serge

    2007-06-15

    In this paper, chemometrics methods were applied to resolve the high performance liquid chromatography (HPLC) fingerprints of complex, many-component substances to compare samples from a batch from a given manufacturer, or from those of different producers. As an example of such complex substances, we used a common Chinese traditional medicine, Huoxiang Zhengqi Tincture (HZT) for this research. Twenty-one samples, each representing a separate HZT production batch from one of three manufacturers were analyzed by HPLC with the aid of a diode array detector (DAD). An Agilent Zorbax Eclipse XDB-C18 column with an Agilent Zorbax high pressure reliance cartridge guard-column were used. The mobile phase consisted of water (A) and methanol (B) with a gradient program of 25-65% (v/v, B) during 0-30min, 65-55% (v/v, B) during 30-35min and 55-100% (v/v, B) during 35-60min (flow rate, 1.0mlmin(-1); injection volume, 20mul; and column temperature-ambient). The detection wavelength was adjusted for maximum sensitivity at different time periods. A peak area matrix with 21objectsx14HPLC variables was obtained by sampling each chromatogram at 14 common retention times. Similarities were then calculated to discriminate the batch-to-batch samples and also, a more informative multi-criteria decision making methodology (MCDM), PROMETHEE and GAIA, was applied to obtain more information from the chromatograms in order to rank and compare the complex HZT profiles. The results showed that with the MCDM analysis, it was possible to match and discriminate correctly the batch samples from the three different manufacturers. Fourier transform infrared (FT-IR) spectra taken from samples from several batches were compared by the common similarity method with the HPLC results. It was found that the FT-IR spectra did not discriminate the samples from the different batches.

  13. Quaternary structure of the ATPase complex of human 26S proteasomes determined by chemical cross-linking

    DEFF Research Database (Denmark)

    Hartmann-Petersen, R; Tanaka, K; Hendil, K B

    2001-01-01

    and substrate specificity. Among the approximately 18 subunits of PA700 regulator, six are ATPases. The ATPases presumably recognize, unfold, and translocate substrates into the interior of the 26S proteasome. It is generally believed that the ATPases form a hexameric ring. By means of chemical cross......-linking, immunoprecipitation, and blotting, we have determined that the ATPases are organized in the order S6-S6'-S10b-S8-S4-S7. Additionally, we found cross-links between the ATPase S10b and the 20S proteasome subunit alpha6. Together with the previously known interaction between S8 and alpha1 and between S4 and alpha7......, these data establish the relative orientations of ATPases with respect to the 20S proteasome....

  14. Reverse osmosis water purification system

    Science.gov (United States)

    Ahlstrom, H. G.; Hames, P. S.; Menninger, F. J.

    1986-01-01

    A reverse osmosis water purification system, which uses a programmable controller (PC) as the control system, was designed and built to maintain the cleanliness and level of water for various systems of a 64-m antenna. The installation operates with other equipment of the antenna at the Goldstone Deep Space Communication Complex. The reverse osmosis system was designed to be fully automatic; with the PC, many complex sequential and timed logic networks were easily implemented and are modified. The PC monitors water levels, pressures, flows, control panel requests, and set points on analog meters; with this information various processes are initiated, monitored, modified, halted, or eliminated as required by the equipment being supplied pure water.

  15. Tubal Ligation Reversal

    Science.gov (United States)

    ... seal off the fallopian tubes, such as the Essure or Adiana systems, generally aren't reversible. Why ... electrocautery). Some types of sterilization, such as the Essure or Adiana systems, aren't considered reversible. Risks ...

  16. Chemical sporulation and germination: cytoprotective nanocoating of individual mammalian cells with a degradable tannic acid-FeIII complex

    Science.gov (United States)

    Lee, Juno; Cho, Hyeoncheol; Choi, Jinsu; Kim, Doyeon; Hong, Daewha; Park, Ji Hun; Yang, Sung Ho; Choi, Insung S.

    2015-11-01

    Individual mammalian cells were coated with cytoprotective and degradable films by cytocompatible processes maintaining the cell viability. Three types of mammalian cells (HeLa, NIH 3T3, and Jurkat cells) were coated with a metal-organic complex of tannic acid (TA) and ferric ion, and the TA-FeIII nanocoat effectively protected the coated mammalian cells against UV-C irradiation and a toxic compound. More importantly, the cell proliferation was controlled by programmed formation and degradation of the TA-FeIII nanocoat, mimicking the sporulation and germination processes found in nature.Individual mammalian cells were coated with cytoprotective and degradable films by cytocompatible processes maintaining the cell viability. Three types of mammalian cells (HeLa, NIH 3T3, and Jurkat cells) were coated with a metal-organic complex of tannic acid (TA) and ferric ion, and the TA-FeIII nanocoat effectively protected the coated mammalian cells against UV-C irradiation and a toxic compound. More importantly, the cell proliferation was controlled by programmed formation and degradation of the TA-FeIII nanocoat, mimicking the sporulation and germination processes found in nature. Electronic supplementary information (ESI) available: Experimental details, LSCM images, and SEM and TEM images. See DOI: 10.1039/c5nr05573c

  17. Laser-induced breakdown spectroscopy (LIBS) technique for the determination of the chemical composition of complex inorganic materials

    Science.gov (United States)

    Łazarek, Łukasz; Antończak, Arkadiusz J.; Wójcik, Michał R.; Kozioł, Paweł E.; Stepak, Bogusz; Abramski, Krzysztof M.

    2014-08-01

    Laser-induced breakdown spectroscopy (LIBS) is a fast, fully optical method, that needs little or no sample preparation. In this technique qualitative and quantitative analysis is based on comparison. The determination of composition is generally based on the construction of a calibration curve namely the LIBS signal versus the concentration of the analyte. Typically, to calibrate the system, certified reference materials with known elemental composition are used. Nevertheless, such samples due to differences in the overall composition with respect to the used complex inorganic materials can influence significantly on the accuracy. There are also some intermediate factors which can cause imprecision in measurements, such as optical absorption, surface structure, thermal conductivity etc. This paper presents the calibration procedure performed with especially prepared pellets from the tested materials, which composition was previously defined. We also proposed methods of post-processing which allowed for mitigation of the matrix effects and for a reliable and accurate analysis. This technique was implemented for determination of trace elements in industrial copper concentrates standardized by conventional atomic absorption spectroscopy with a flame atomizer. A series of copper flotation concentrate samples was analyzed for contents of three elements, that is silver, cobalt and vanadium. It has been shown that the described technique can be used to qualitative and quantitative analyses of complex inorganic materials, such as copper flotation concentrates.

  18. A chemical-biological evaluation of rhodium(I) N-heterocyclic carbene complexes as prospective anticancer drugs.

    Science.gov (United States)

    Oehninger, Luciano; Küster, Laura Nadine; Schmidt, Claudia; Muñoz-Castro, Alvaro; Prokop, Aram; Ott, Ingo

    2013-12-23

    Rhodium(I) complexes bearing N-heterocyclic carbene (NHC) ligands have been widely used in catalytic chemistry, but there are very few reports of biological properties of these organometallics. A series of Rh(I)-NHC derivatives with 1,5-cyclooctadiene and CO as secondary ligands were synthesized, characterized, and biologically investigated as prospective antitumor drug candidates. Pronounced antiproliferative effects were noted for all complexes, along with moderate inhibitory activity of thioredoxin reductase (TrxR) and efficient binding to biomolecules (DNA, albumin). Biodistribution studies showed that the presence of albumin lowered the cellular uptake and confirmed the transport of rhodium into the nuclei. Changes in the mitochondrial membrane potential (MMP) were observed as well as DNA fragmentation in wild-type and daunorubicin- or vincristine-resistant Nalm-6 leukemia cells. Overall, these studies indicated that Rh(I)-NHC fragments could be used as partial structures of new antitumor agents, in particular in those drugs designed to address resistant malignant tissues. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Complexes of lutein with bovine and caprine caseins and their impact on lutein chemical stability in emulsion systems: Effect of arabinogalactan.

    Science.gov (United States)

    Mora-Gutierrez, A; Attaie, R; Núñez de González, M T; Jung, Y; Woldesenbet, S; Marquez, S A

    2018-01-01

    Lutein is an important xanthophyll carotenoid with many benefits to human health. Factors affecting the application of lutein as a functional ingredient in low-fat dairy-like beverages (pH 6.0-7.0) are not well understood. The interactions of bovine and caprine caseins with hydrophobic lutein were studied using UV/visible spectroscopy as well as fluorescence. Our studies confirmed that the aqueous solubility of lutein is improved after binding with bovine and caprine caseins. The rates of lutein solubilization by the binding to bovine and caprine caseins were as follows: caprine α S1 -II-casein 34%, caprine α S1 -I-casein 10%, and bovine casein 7% at 100 μM lutein. Fluorescence of the protein was quenched on binding supporting complex formation. The fluorescence experiments showed that the binding involves tryptophan residues and some nonspecific interactions. Scatchard plots of lutein binding to the caseins demonstrated competitive binding between the caseins and their sites of interaction with lutein. Competition experiments suggest that caprine α S1 -II casein will bind a larger number of lutein molecules with higher affinity than other caseins. The chemical stability of lutein was largely dependent on casein type and significant increases occurred in the chemical stability of lutein with the following pattern: caprine α S1 -II-casein > caprine α S1 -I-casein > bovine casein. Addition of arabinogalactan to lutein-enriched emulsions increases the chemical stability of lutein-casein complexes during storage under accelerated photo-oxidation conditions at 25°C. Therefore, caprine α S1 -II-casein alone and in combination with arabinogalactan can have important applications in the beverage industry as carrier of this xanthophyll carotenoid (lutein). Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  20. Characterization of Cu–Ni nanostructured alloys obtained by a chemical route. Influence of the complexing agent content in the starting solution

    Energy Technology Data Exchange (ETDEWEB)

    Carreras, Alejo C., E-mail: acarreras@famaf.unc.edu.ar [Instituto de Física Enrique Gaviola (IFEG), Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba—CONICET, Medina Allende s/n, Ciudad Universitaria, 5016 Córdoba (Argentina); Cangiano, María de los A.; Ojeda, Manuel W.; Ruiz, María del C. [Instituto de Investigaciones en Tecnología Qumica (INTEQUI), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis—CONICET, Chacabuco y Pedernera, 5700 San Luis (Argentina)

    2015-03-15

    The influence of the amount of complexing agent added to the starting solution on the physicochemical properties of Cu–Ni nanostructured alloys obtained through a chemical route, was studied. For this purpose, three Cu–Ni nanoalloy samples were synthesized by a previously developed procedure, starting from solutions with citric acid to metal molar ratios (C/Me) of 0.73, 1.00 and 1.50. The synthesis technique consisted in preparing a precursor via the citrate-gel method, and carrying out subsequent thermal treatments in controlled atmospheres. Sample characterization was performed by scanning electron microscopy, X-ray microanalysis, X-ray diffraction, transmission electron microscopy, X-ray nanoanalysis and electron diffraction. In the three cases, copper and nickel formed a solid solution with a Cu/Ni atomic ratio close to 50/50, and free of impurities inside the crystal structure. The citric acid content of the starting solution proved to have an important influence on the morphology, size distribution, porosity, and crystallinity of the Cu–Ni alloy microparticles obtained, but a lesser influence on their chemical composition. The molar ratio C/Me = 1.00 resulted in the alloy with the Cu/Ni atomic ratio closest to 50/50. - Highlights: • We synthesize Cu–Ni nanoalloys by a chemical route based on the citrate-gel method. • We study the influence of the complexing agent content of the starting solution. • We characterize the samples by electron microscopy and X-ray techniques. • Citric acid influences the shape, size, porosity and crystallinity of the alloys.

  1. SMA OBSERVATIONS OF THE W3(OH) COMPLEX: PHYSICAL AND CHEMICAL DIFFERENTIATION BETWEEN W3(H{sub 2}O) AND W3(OH)

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Sheng-Li [Department of Astronomy, Yunnan University, and Key Laboratory of Astroparticle Physics of Yunnan Province, Kunming, 650091 (China); Schilke, Peter; Sánchez-Monge, Álvaro [Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln (Germany); Wu, Jingwen [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Wu, Yuefang [Department of Astronomy, Peking University, Beijing, 100871 (China); Liu, Tie [Korea Astronomy and Space Science Institute 776, Daedeokdaero, Yuseong-gu, Daejeon, Korea 305-348 (Korea, Republic of); Liu, Ying, E-mail: slqin@bao.ac.cn [Department of Physics and Hebei Advanced Thin Film Laboratory, Hebei Normal University, Shijiazhuang 050024 (China)

    2015-04-10

    We report on the Submillimeter Array (SMA) observations of molecular lines at 270 GHz toward the W3(OH) and W3(H{sub 2}O) complex. Although previous observations already resolved the W3(H{sub 2}O) into two or three sub-components, the physical and chemical properties of the two sources are not well constrained. Our SMA observations clearly resolved the W3(OH) and W3(H{sub 2}O) continuum cores. Taking advantage of the line fitting tool XCLASS, we identified and modeled a rich molecular spectrum in this complex, including multiple CH{sub 3}CN and CH{sub 3}OH transitions in both cores. HDO, C{sub 2}H{sub 5}CN, O{sup 13}CS, and vibrationally excited lines of HCN, CH{sub 3}CN, and CH{sub 3}OCHO were only detected in W3(H{sub 2}O). We calculate gas temperatures and column densities for both cores. The results show that W3(H{sub 2}O) has higher gas temperatures and larger column densities than W3(OH) as previously observed, suggesting physical and chemical differences between the two cores. We compare the molecular abundances in W3(H{sub 2}O) to those in the Sgr B2(N) hot core, the Orion KL hot core, and the Orion Compact Ridge, and discuss the chemical origin of specific species. An east–west velocity gradient is seen in W3(H{sub 2}O), and the extension is consistent with the bipolar outflow orientation traced by water masers and radio jets. A north–south velocity gradient across W3(OH) is also observed. However, with current observations we cannot be assured whether the velocity gradients are caused by rotation, outflow, or radial velocity differences of the sub-components of W3(OH)

  2. Reverse logistics - a framework

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of

  3. Complexation reactions in pyridine and 2,6-dimethylpyridine-water system: The quantum-chemical description and the path to liquid phase separation

    Science.gov (United States)

    Chernia, Zelig; Tsori, Yoav

    2018-03-01

    Phase separation in substituted pyridines in water is usually described as an interplay between temperature-driven breakage of hydrogen bonds and the associating interaction of the van der Waals force. In previous quantum-chemical studies, the strength of hydrogen bonding between one water and one pyridine molecules (the 1:1 complex) was assigned a pivotal role. It was accepted that the disassembly of the 1:1 complex at a critical temperature leads to phase separation and formation of the miscibility gap. Yet, for over two decades, notable empirical data and theoretical arguments were presented against that view, thus revealing the need in a revised quantum-mechanical description. In the present study, pyridine-water and 2,6-dimethylpyridine-water systems at different complexation stages are calculated using high level Kohn-Sham theory. The hydrophobic-hydrophilic properties are accounted for by the polarizable continuum solvation model. Inclusion of solvation in free energy of formation calculations reveals that 1:1 complexes are abundant in the organically rich solvents but higher level oligomers (i.e., 2:1 dimers with two pyridines and one water molecule) are the only feasible stable products in the more polar media. At the critical temperature, the dissolution of the external hydrogen bonds between the 2:1 dimer and the surrounding water molecules induces the demixing process. The 1:1 complex acts as a precursor in the formation of the dimers but is not directly involved in the demixing mechanism. The existence of the miscibility gap in one pyridine-water system and the lack of it in another is explained by the ability of the former to maintain stable dimerization. Free energy of formation of several reaction paths producing the 2:1 dimers is calculated and critically analyzed.

  4. Chemical synthesis and X-ray structure of a heterochiral {D-protein antagonist plus vascular endothelial growth factor} protein complex by racemic crystallography.

    Science.gov (United States)

    Mandal, Kalyaneswar; Uppalapati, Maruti; Ault-Riché, Dana; Kenney, John; Lowitz, Joshua; Sidhu, Sachdev S; Kent, Stephen B H

    2012-09-11

    Total chemical synthesis was used to prepare the mirror image (D-protein) form of the angiogenic protein vascular endothelial growth factor (VEGF-A). Phage display against D-VEGF-A was used to screen designed libraries based on a unique small protein scaffold in order to identify a high affinity ligand. Chemically synthesized D- and L- forms of the protein ligand showed reciprocal chiral specificity in surface plasmon resonance binding experiments: The L-protein ligand bound only to D-VEGF-A, whereas the D-protein ligand bound only to L-VEGF-A. The D-protein ligand, but not the L-protein ligand, inhibited the binding of natural VEGF(165) to the VEGFR1 receptor. Racemic protein crystallography was used to determine the high resolution X-ray structure of the heterochiral complex consisting of {D-protein antagonist + L-protein form of VEGF-A}. Crystallization of a racemic mixture of these synthetic proteins in appropriate stoichiometry gave a racemic protein complex of more than 73 kDa containing six synthetic protein molecules. The structure of the complex was determined to a resolution of 1.6 Å. Detailed analysis of the interaction between the D-protein antagonist and the VEGF-A protein molecule showed that the binding interface comprised a contact surface area of approximately 800 Å(2) in accord with our design objectives, and that the D-protein antagonist binds to the same region of VEGF-A that interacts with VEGFR1-domain 2.

  5. Nitrogen complex species and its chemical nature in TiO2 for visible-light sensitized photocatalysis

    International Nuclear Information System (INIS)

    Asahi, Ryoji; Morikawa, Takeshi

    2007-01-01

    A photocatalyst with high reactivity under visible-light has been desired to utilize solar irradiation or interior lighting efficiently. Nitrogen-doped TiO 2 revealed significant improvement in optical absorption and photocatalytic activity over TiO 2 under visible light. We have performed the first-principles calculations to study the detailed N complex species introduced in TiO 2 . The results include stable geometries, densities of states, formation energies, and core levels. The present systematic studies account for the long-term controversial issue on N-doped TiO 2 , in particular, regarding the detailed assignment of N 1s binding energies observed in the XPS measurement. The detailed analyses of the formation energies show that introducing the N species more in a controlled way via process conditions is crucial to achieve the optimized photocatalytic performance

  6. The quantum-chemical modeling of structure and spectral characteristics for molecular complexes in system «penton-terlon»

    Directory of Open Access Journals (Sweden)

    Andrey V. Tokar

    2014-03-01

    Full Text Available The structure and spectral properties for molecular complexes, which formed by added monomer form of pentaplast as well as N-phenylbenzamide with some species of intermolecular interaction in system «penton-terlon» have been investigated at ab initio level of theory. It is shown, that the main contribution in total energy of molecules have included by dispersion forces, which realized between Chlorine atom of CH2Cl-group and Hydrogen atoms of benzene rings with amide fragment. The proposed theoretical models are validated in reflection of spectral and energetic characteristics of investigating system. Finally, the results of calculations are in good agreement with that data, which have been obtained for such type modeling previously.

  7. Chemical and biological evaluation of 153Sm and 46/47Sc complexes of indazolebisphosphonates for targeted radiotherapy

    International Nuclear Information System (INIS)

    Neves, Maria; Teixeira, Fatima C.; Antunes, Ines; Majkowska, Agnieszka; Gano, Lurdes; Santos, Ana Cristina

    2011-01-01

    Introduction: Novel 1-hydroxy-1,1-bisphosphonates derived from indazole and substituted at the C-3 position were labeled with the radionuclides 46 Sc and 153 Sm. Several parameters such as molar ligand concentration, pH, reaction time and temperature were studied. The radiolabelling yield, reaction kinetics and stability were assessed and radiocomplexes were evaluated by in vitro and in vivo experiments. Methods: The radionuclides 46 Sc and 153 Sm were obtained by neutron irradiation of natural Sc 2 O 3 and enriched 152 Sm 2 O 3 (98.4%) targets at the neutron flux of 3x10 14 n cm -2 s -1 . The radiolabelling yield, reaction kinetics and stability were accomplished by ascending instant thin layer chromatography. The radiocomplexes were submitted to in vitro experiments (hydroxyapatite binding and lipophilicity) and biodistribution studies in animal models. Results: The radionuclides 46 Sc and 153 Sm were produced with specific activities of 100 and 430 MBq mg -1 , respectively. High radiochemical yields were achieved and the hydrophilic radiocomplexes have shown high degree of binding to hydroxyapatite. Biodistribution studies at 1, 3 and 24 h of the 4 radiocomplexes under study, have showed a similar biodistribution profile with a relatively high bone uptake, slow clearance from blood and a very slow rate of total radioactivity excretion from the whole animal body. Conclusion: We have developed a new class of indazolebisphosphonates complexes with radioisotopes of samarium and scandium. All complexes have shown high degree of binding to hydroxyapatite, which could be attributed to the ionized phosphonate groups. The bone uptake and the bone-to-muscle ratios were relatively low.

  8. Chemical and biological evaluation of {sup 153}Sm and {sup 46/47}Sc complexes of indazolebisphosphonates for targeted radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Neves, Maria, E-mail: mneves@itn.p [Instituto Tecnologico e Nuclear, Sacavem (Portugal); Teixeira, Fatima C.; Antunes, Ines [INETI-Departamento de Tecnologia de Industrias Quimicas, Lisboa (Portugal); Majkowska, Agnieszka [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Gano, Lurdes [Instituto Tecnologico e Nuclear, Sacavem (Portugal); Santos, Ana Cristina [IBB-Instituto de Biofisica e Biomatematica, Coimbra (Portugal)

    2011-01-15

    Introduction: Novel 1-hydroxy-1,1-bisphosphonates derived from indazole and substituted at the C-3 position were labeled with the radionuclides {sup 46}Sc and {sup 153}Sm. Several parameters such as molar ligand concentration, pH, reaction time and temperature were studied. The radiolabelling yield, reaction kinetics and stability were assessed and radiocomplexes were evaluated by in vitro and in vivo experiments. Methods: The radionuclides {sup 46}Sc and {sup 153}Sm were obtained by neutron irradiation of natural Sc{sub 2}O{sub 3} and enriched {sup 152}Sm{sub 2}O{sub 3} (98.4%) targets at the neutron flux of 3x10{sup 14} n cm{sup -2} s{sup -1}. The radiolabelling yield, reaction kinetics and stability were accomplished by ascending instant thin layer chromatography. The radiocomplexes were submitted to in vitro experiments (hydroxyapatite binding and lipophilicity) and biodistribution studies in animal models. Results: The radionuclides {sup 46}Sc and {sup 153}Sm were produced with specific activities of 100 and 430 MBq mg{sup -1}, respectively. High radiochemical yields were achieved and the hydrophilic radiocomplexes have shown high degree of binding to hydroxyapatite. Biodistribution studies at 1, 3 and 24 h of the 4 radiocomplexes under study, have showed a similar biodistribution profile with a relatively high bone uptake, slow clearance from blood and a very slow rate of total radioactivity excretion from the whole animal body. Conclusion: We have developed a new class of indazolebisphosphonates complexes with radioisotopes of samarium and scandium. All complexes have shown high degree of binding to hydroxyapatite, which could be attributed to the ionized phosphonate groups. The bone uptake and the bone-to-muscle ratios were relatively low.

  9. Rotating Reverse-Osmosis for Water Purification

    Science.gov (United States)

    Lueptow, RIchard M.

    2004-01-01

    A new design for a water-filtering device combines rotating filtration with reverse osmosis to create a rotating reverse- osmosis system. Rotating filtration has been used for separating plasma from whole blood, while reverse osmosis has been used in purification of water and in some chemical processes. Reverse- osmosis membranes are vulnerable to concentration polarization a type of fouling in which the chemicals meant not to pass through the reverse-osmosis membranes accumulate very near the surfaces of the membranes. The combination of rotating filtration and reverse osmosis is intended to prevent concentration polarization and thereby increase the desired flux of filtered water while decreasing the likelihood of passage of undesired chemical species through the filter. Devices based on this concept could be useful in a variety of commercial applications, including purification and desalination of drinking water, purification of pharmaceutical process water, treatment of household and industrial wastewater, and treatment of industrial process water. A rotating filter consists of a cylindrical porous microfilter rotating within a stationary concentric cylindrical outer shell (see figure). The aqueous suspension enters one end of the annulus between the inner and outer cylinders. Filtrate passes through the rotating cylindrical microfilter and is removed via a hollow shaft. The concentrated suspension is removed at the end of the annulus opposite the end where the suspension entered.

  10. Electrochemical properties of the hexacyanoferrate(II)–ruthenium(III) complex immobilized on silica gel surface chemically modified with zirconium(IV) oxide

    International Nuclear Information System (INIS)

    Panice, Lucimara B.; Oliveira, Elisangela A. de; Filho, Ricardo A.D. Molin; Oliveira, Daniela P. de; Lazarin, Angélica M.; Andreotti, Elza I.S.; Sernaglia, Rosana L.; Gushikem, Yoshitaka

    2014-01-01

    Highlights: • The cyano-bridged mixed valence ruthenium composite material was synthesized. • This newly synthesized compound was incorporated into a carbon paste electrode. • The electrode did not show significant changes in response after six months of use. • The modified electrode is very stable and reproducible. • The electrode sensor was successfully applied for ascorbic acid determination. - Abstract: The chemically modified silica gel with zirconium(IV) oxide was used to immobilize the [Fe(CN) 6 ] 4− complex ion initially. The reaction of this material with [Ru(edta)H 2 O] − complex ion formed the immobilized cyano-bridged mixed valence ruthenium complex, (≡Zr) 5 [(edta)RuNCFe(CN) 5 ]. This material was incorporated into a carbon paste electrode and, its electrochemical properties were investigated. However, for an ascorbic acid solution, an enhancement of the anodic peak current was detected due to electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, with a good repeatability. The modified electrode is very stable and reproducible. The sensor was applied for ascorbic acid determination in pharmaceutical preparation with success

  11. Variations in atmospheric PM trace metal content in Spanish towns: Illustrating the chemical complexity of the inorganic urban aerosol cocktail

    Science.gov (United States)

    Moreno, Teresa; Querol, Xavier; Alastuey, Andrés; Viana, Mar; Salvador, Pedro; Sánchez de la Campa, Ana; Artiñano, Begoña; de la Rosa, Jesús; Gibbons, Wes

    The majority of the Spanish urban population breathe air containing inhalable ambient airborne particles at average concentrations of 30-46 μg m -3 (PM 10) and 20-30 μg m -3 (PM 2.5). Even though the average weight of inhaled urban aerosol is commonly similar, however, there can be large chemical differences between the ambient dusts from different towns, including the more bioreactive elements such as some metals. In this context, we compare the source-apportioned trace metal content of airborne PM 10 and PM 2.5 collected daily over a 1-year period from six population centres in Spain: Barcelona, Alcobendas, Llodio, Huelva, Tarragona and Las Palmas de Gran Canaria. Total average trace metal (ΣTM) PM 10 and PM 2.5 contents vary by up to a factor of around 3, reaching a maximum of ΣTM 10 811 ng m -3 and ΣTM 2.5 503 ng m -3 at Llodio, an industrial but humid site with the lowest PM 10 mass levels but high contamination by Zn, Pb, Mn, Sn, Ni and Cr. In contrast, pollution at Huelva, although another industrially influenced site, instead emphasises Cu and As, whereas Barcelona, where traffic emissions and resuspension contribute to some of the highest average PM 10 levels in Spain, has unusually raised levels of Ti, V and Ba. Such variations in both daily and annual average PM bulk chemistry, particularly in potentially toxic trace metals concentrated in the finer aerosols (such as Cd, As, Pb, Hg and Ni), predict that PM health effects on resident populations from different towns are unlikely to be the same.

  12. Alkynes as a versatile platform for construction of chemical molecular complexity and realization of molecular 3D printing

    International Nuclear Information System (INIS)

    Galkin, K I; Ananikov, V P

    2016-01-01

    The current level of scientific and technological development requires the formation of general tools and techniques. One of the most versatile technologies is 3D printing, which allows fast and efficient creation of materials and biological objects of desired shape and composition. Today, methods have been developed for 3D printing of macro- and nano-sized objects and for production of films and deposited materials with molecular precision but the most promising technology is printing at the molecular level (molecular 3D printing) for the purpose of direct construction of molecular complexity. This process is currently at the initial stage concerning selection of simple molecules to be used as building blocks possessing flexibility, availability and ease of modification. In this review, we examine the possible versatile synthons suitable for preparation of the main types of organic compounds using molecular 3D printing. The surveyed data strongly indicate that alkyne molecules may be used as a building material in a molecular 3D printer working on hydrocarbons. The bibliography includes 428 references

  13. Support vector regression scoring of receptor-ligand complexes for rank-ordering and virtual screening of chemical libraries.

    Science.gov (United States)

    Li, Liwei; Wang, Bo; Meroueh, Samy O

    2011-09-26

    The community structure-activity resource (CSAR) data sets are used to develop and test a support vector machine-based scoring function in regression mode (SVR). Two scoring functions (SVR-KB and SVR-EP) are derived with the objective of reproducing the trend of the experimental binding affinities provided within the two CSAR data sets. The features used to train SVR-KB are knowledge-based pairwise potentials, while SVR-EP is based on physicochemical properties. SVR-KB and SVR-EP were compared to seven other widely used scoring functions, including Glide, X-score, GoldScore, ChemScore, Vina, Dock, and PMF. Results showed that SVR-KB trained with features obtained from three-dimensional complexes of the PDBbind data set outperformed all other scoring functions, including best performing X-score, by nearly 0.1 using three correlation coefficients, namely Pearson, Spearman, and Kendall. It was interesting that higher performance in rank ordering did not translate into greater enrichment in virtual screening assessed using the 40 targets of the Directory of Useful Decoys (DUD). To remedy this situation, a variant of SVR-KB (SVR-KBD) was developed by following a target-specific tailoring strategy that we had previously employed to derive SVM-SP. SVR-KBD showed a much higher enrichment, outperforming all other scoring functions tested, and was comparable in performance to our previously derived scoring function SVM-SP.

  14. Structural analysis of ternary actinyl(V/VI) sorption complexes on gibbsite. A combined quantum chemical and spectroscopic approach

    Energy Technology Data Exchange (ETDEWEB)

    Gueckel, Katharina

    2013-10-08

    For the safety assessment of high-level nuclear waste repositories, it is mandatory to know the transportation paths of contaminants, e.g. actinyl ions, in the geological barrier. The most attention needs to be focused on the transport in aquifers, because water contamination, depending on retention and migration processes of radionuclides in the geosphere, is of primary environmental concern. The migration behavior of actinides in ground water is mainly controlled by aquatic speciations and sorption processes at water-mineral interfaces. Hence, the investigation of complexspecies in aqueous solutions and at mineral surfaces becomes essential for the safety assessment in the near and far field of nuclear repositories. For deep ground repositories, clay and clay minerals are considered as possible host rocks, because they show a low permeability and are expected to have a high retention capacity towards actinyl ions. But the complexity of naturally occurring minerals in particular their surface often hampers the unequivocal interpretation of results obtained from sorption experiments. The use of model phases only showing one particular functional group at the surfaces with a well defined surface topology is an appropriate approach for the understanding of the basic sorption processes. Aluminum oxide and hydroxides are of special interest because they represent main components in clays and clay minerals. In particular, gibbsite is widely used as a model system because it represents not only the most common crystalline aluminum hydroxide but also a ubiquitous weathering product of alumosilicates. Furthermore, the elemental structural unit of gibbsite, that is the Al(OH)6 octahedron, occurs ubiquitously as part of the structure of common clay minerals like kaolinite. In the present study, the sorption processes of U(VI) and Np(V) on gibbsite were studied under consideration of the aqueous speciation.

  15. Theoretical study of the electronic structure of f-element complexes by quantum chemical methods; Analyse de la structure electronique des complexes contenant des elements F par des methodes de la chimie quantique

    Energy Technology Data Exchange (ETDEWEB)

    Vetere, V

    2002-09-15

    This thesis is related to comparative studies of the chemical properties of molecular complexes containing lanthanide or actinide trivalent cations, in the context of the nuclear waste disposal. More precisely, our aim was a quantum chemical analysis of the metal-ligand bonding in such species. Various theoretical approaches were compared, for the inclusion of correlation (density functional theory, multiconfigurational methods) and of relativistic effects (relativistic scalar and 2-component Hamiltonians, relativistic pseudopotentials). The performance of these methods were checked by comparing computed structural properties to published experimental data, on small model systems: lanthanide and actinide tri-halides and on X{sub 3}M-L species (X=F, Cl; M=La, Nd, U; L = NH{sub 3}, acetonitrile, CO). We have thus shown the good performance of density functionals combined with a quasi-relativistic method, as well as of gradient-corrected functionals associated with relativistic pseudopotentials. In contrast, functionals including some part of exact exchange are less reliable to reproduce experimental trends, and we have given a possible explanation for this result . Then, a detailed analysis of the bonding has allowed us to interpret the discrepancies observed in the structural properties of uranium and lanthanides complexes, based on a covalent contribution to the bonding, in the case of uranium(III), which does not exist in the lanthanide(III) homologues. Finally, we have examined more sizeable systems, closer to experimental species, to analyse the influence of the coordination number, of the counter-ions and of the oxidation state of uranium, on the metal-ligand bonding. (author)

  16. Reversible flowchart languages and the structured reversible program theorem

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    Many irreversible computation models have reversible counterparts, but these are poorly understood at present. We introduce reversible flowcharts with an assertion operator and show that any reversible flowchart can be simulated by a structured reversible flowchart using only three control flow...... operators. Reversible flowcharts are r- Turing-complete, meaning that they can simuluate reversible Turing machines without garbage data. We also demonstrate the injectivization of classical flowcharts into reversible flowcharts. The reversible flowchart computation model provides a theoretical...

  17. Global minimum profile error (GMPE) - a least-squares-based approach for extracting macroscopic rate coefficients for complex gas-phase chemical reactions.

    Science.gov (United States)

    Duong, Minh V; Nguyen, Hieu T; Mai, Tam V-T; Huynh, Lam K

    2018-01-03

    Master equation/Rice-Ramsperger-Kassel-Marcus (ME/RRKM) has shown to be a powerful framework for modeling kinetic and dynamic behaviors of a complex gas-phase chemical system on a complicated multiple-species and multiple-channel potential energy surface (PES) for a wide range of temperatures and pressures. Derived from the ME time-resolved species profiles, the macroscopic or phenomenological rate coefficients are essential for many reaction engineering applications including those in combustion and atmospheric chemistry. Therefore, in this study, a least-squares-based approach named Global Minimum Profile Error (GMPE) was proposed and implemented in the MultiSpecies-MultiChannel (MSMC) code (Int. J. Chem. Kinet., 2015, 47, 564) to extract macroscopic rate coefficients for such a complicated system. The capability and limitations of the new approach were discussed in several well-defined test cases.

  18. Deposition and characterization of ZnS thin films using chemical bath deposition method in the presence of sodium tartrate as complexing agent

    International Nuclear Information System (INIS)

    Kassim, A.; Tee, T.W.; Min, H.S.; Nagalingam, S.

    2011-01-01

    ZnS thin films were deposited on indium tin oxide glass substrate using the chemical bath deposition method. The deposited films were characterized by X-ray diffraction and atomic force microscopy. The influence of bath temperature on the structure and morphology of the thin films was investigated at three different bath temperatures of 60, 70 and 80 deg. C in the presence of sodium tartrate as a complexing agent. The XRD results indicated that the deposited ZnS thin films exhibited a polycrystalline cubic structure. The number of ZnS peaks increased from three to four peaks as the bath temperature was increased from 60 to 80 deg. C based on the XRD patterns. From the AFM measurements, the film thickness and surface roughness were found to be dependent on the bath temperature. The grain size increased as the bath temperature was increased from 60 to 80 deg. C. (author)

  19. Designing Novel Quaternary Quantum Reversible Subtractor Circuits

    Science.gov (United States)

    Haghparast, Majid; Monfared, Asma Taheri

    2018-01-01

    Reversible logic synthesis is an important area of current research because of its ability to reduce energy dissipation. In recent years, multiple valued logic has received great attention due to its ability to reduce the width of the reversible circuit which is a main requirement in quantum technology. Subtractor circuits are between major components used in quantum computers. In this paper, we will discuss the design of a quaternary quantum reversible half subtractor circuit using quaternary 1-qudit, 2-qudit Muthukrishnan-Stroud and 3-qudit controlled gates and a 2-qudit Generalized quaternary gate. Then a design of a quaternary quantum reversible full subtractor circuit based on the quaternary half subtractor will be presenting. The designs shall then be evaluated in terms of quantum cost, constant input, garbage output, and hardware complexity. The proposed quaternary quantum reversible circuits are the first attempt in the designing of the aforementioned subtractor.

  20. Surface-driven, one-step chemical vapor deposition of γ-Al{sub 4}Cu{sub 9} complex metallic alloy film

    Energy Technology Data Exchange (ETDEWEB)

    Prud’homme, Nathalie [CIRIMAT, Université de Toulouse - CNRS, 4 allée Emile Monso, BP-44362, 31432 Toulouse Cedex 4 (France); Université Paris-Sud 11, LEMHE/ICMMO, Bat 410, 91405 Orsay Cedex (France); Duguet, Thomas, E-mail: thomas.duguet@ensiacet.fr [CIRIMAT, Université de Toulouse - CNRS, 4 allée Emile Monso, BP-44362, 31432 Toulouse Cedex 4 (France); Samélor, Diane; Senocq, François; Vahlas, Constantin [CIRIMAT, Université de Toulouse - CNRS, 4 allée Emile Monso, BP-44362, 31432 Toulouse Cedex 4 (France)

    2013-10-15

    The present paper is a paradigm for the one-step formation of complex intermetallic coatings by chemical vapor deposition. It genuinely addresses the challenge of depositing an intermetallic coating with comparable contents of Cu and Al. Depending on processing conditions, a pure γ-Al{sub 4}Cu{sub 9} and multi-phase Al-Cu films are grown with wetting properties of the former being similar to its bulk counterpart. The deposition process and its parametric investigation are detailed. Two metalorganic precursors are used taking into account their transport and chemical properties, and deposition temperature ranges. On line and ex situ characterizations enlighten the competition which occurs at the growing surface between molecular fragments, and which limits growth rates. Notably, introducing a partial pressure of hydrogen gas during deposition reduces Al growth rate from dimethylethylamine alane (DMEAA), by displacing the hydrogen desorption equilibrium. This Al partial growth rate decrease is not sufficient to achieve a Cu/Al atomic ratio that is high enough for the formation of intermetallics with close Al and Cu compositions. A fivefold increase of the flux of the gaseous copper(I) cyclopentadienyl triethylphosphine CpCuPEt{sub 3}, whereas the DMEAA flux remains constant, results in the targeted Al/Cu atomic ratio equal to 44/56. Nevertheless, the global growth rate is rendered extremely low by the deposition inhibition caused by a massive phosphine adsorption (-PEt{sub 3}). Despite these limitations, the results pave the way towards the conformal coating of complex surface geometries by such intermetallic compounds.

  1. FastChem: A computer program for efficient complex chemical equilibrium calculations in the neutral/ionized gas phase with applications to stellar and planetary atmospheres

    Science.gov (United States)

    Stock, Joachim W.; Kitzmann, Daniel; Patzer, A. Beate C.; Sedlmayr, Erwin

    2018-06-01

    For the calculation of complex neutral/ionized gas phase chemical equilibria, we present a semi-analytical versatile and efficient computer program, called FastChem. The applied method is based on the solution of a system of coupled nonlinear (and linear) algebraic equations, namely the law of mass action and the element conservation equations including charge balance, in many variables. Specifically, the system of equations is decomposed into a set of coupled nonlinear equations in one variable each, which are solved analytically whenever feasible to reduce computation time. Notably, the electron density is determined by using the method of Nelder and Mead at low temperatures. The program is written in object-oriented C++ which makes it easy to couple the code with other programs, although a stand-alone version is provided. FastChem can be used in parallel or sequentially and is available under the GNU General Public License version 3 at https://github.com/exoclime/FastChem together with several sample applications. The code has been successfully validated against previous studies and its convergence behavior has been tested even for extreme physical parameter ranges down to 100 K and up to 1000 bar. FastChem converges stable and robust in even most demanding chemical situations, which posed sometimes extreme challenges for previous algorithms.

  2. Computer Program for Calculation of Complex Chemical Equilibrium Compositions and Applications II. Users Manual and Program Description. 2; Users Manual and Program Description

    Science.gov (United States)

    McBride, Bonnie J.; Gordon, Sanford

    1996-01-01

    This users manual is the second part of a two-part report describing the NASA Lewis CEA (Chemical Equilibrium with Applications) program. The program obtains chemical equilibrium compositions of complex mixtures with applications to several types of problems. The topics presented in this manual are: (1) details for preparing input data sets; (2) a description of output tables for various types of problems; (3) the overall modular organization of the program with information on how to make modifications; (4) a description of the function of each subroutine; (5) error messages and their significance; and (6) a number of examples that illustrate various types of problems handled by CEA and that cover many of the options available in both input and output. Seven appendixes give information on the thermodynamic and thermal transport data used in CEA; some information on common variables used in or generated by the equilibrium module; and output tables for 14 example problems. The CEA program was written in ANSI standard FORTRAN 77. CEA should work on any system with sufficient storage. There are about 6300 lines in the source code, which uses about 225 kilobytes of memory. The compiled program takes about 975 kilobytes.

  3. Modeling pH variation in reverse osmosis.

    Science.gov (United States)

    Nir, Oded; Bishop, Noga Fridman; Lahav, Ori; Freger, Viatcheslav

    2015-12-15

    The transport of hydronium and hydroxide ions through reverse osmosis membranes constitutes a unique case of ionic species characterized by uncommonly high permeabilities. Combined with electromigration, this leads to complex behavior of permeate pH, e.g., negative rejection, as often observed for monovalent ions in nanofiltration of salt mixtures. In this work we employed a rigorous phenomenological approach combined with chemical equilibrium to describe the trans-membrane transport of hydronium and hydroxide ions along with salt transport and calculate the resulting permeate pH. Starting from the Nernst-Planck equation, a full non-linear transport equation was derived, for which an approximate solution was proposed based on the analytical solution previously developed for trace ions in a dominant salt. Using the developed approximate equation, transport coefficients were deduced from experimental results obtained using a spiral wound reverse osmosis module operated under varying permeate flux (2-11 μm/s), NaCl feed concentrations (0.04-0.18 M) and feed pH values (5.5-9.0). The approximate equation agreed well with the experimental results, corroborating the finding that diffusion and electromigration, rather than a priori neglected convection, were the major contributors to the transport of hydronium and hydroxide. The approach presented here has the potential to improve the predictive capacity of reverse osmosis transport models for acid-base species, thereby improving process design/control. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Modified Borohydrides for Reversible Hydrogen Storage (2)

    International Nuclear Information System (INIS)

    Ming Au

    2006-01-01

    This paper reports the results in the effort to destabilize lithium borohydride for reversible hydrogen storage. A number of metals, metal hydrides, metal chlorides and complex hydrides were selected and evaluated as the destabilization agents for reducing de-hydriding temperature and generating de-hydriding-re-hydriding reversibility. It is found that some additives are effective. The Raman spectroscopic analysis shows the change of B-H binding nature. (authors)

  5. Introduction to reversible computing

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Few books comprehensively cover the software and programming aspects of reversible computing. Filling this gap, Introduction to Reversible Computing offers an expanded view of the field that includes the traditional energy-motivated hardware viewpoint as well as the emerging application-motivated software approach. Collecting scattered knowledge into one coherent account, the book provides a compendium of both classical and recently developed results on reversible computing. It explores up-and-coming theories, techniques, and tools for the application of rever

  6. Synthesis of ZnS films on Si(100) wafers by using chemical bath deposition assisted by the complexing agent ethylenediamine

    Science.gov (United States)

    Zhu, He-Jie; Wang, Xue-Mei; Gao, Xiao-Yong

    2015-07-01

    Low-cost synthesis of high-quality ZnS films on silicon wafers is of much importance to the ZnSbased heterojunction blue light-emitting device integrated with silicon. Thus, a series of ZnS films were chemically synthesized at low cost on Si(100) wafers at 353 K under a mixed acidic solution with a pH of 4 with zinc acetate and thioacetamide as precursors and with ethylenediamine and hydrochloric acid as the complexing agent and the pH value modifier, respectively. The effects of the ethylenediamine concentration on the crystallization, surface morphology, and optical properties of the ZnS films were investigated by using X-ray diffractometry, scanning electron microscopy, spectrophotometry, and fluorescence spectroscopy. A mechanism for the formation of ZnS film under an acidic condition was also proposed. All of the ZnS films were polycrystalline in nature, with a dominant cubic phase and a small amounts of hexagonal phases. The crystallization and the surface pattern of the films were clearly improved with increasing ethylenediamine concentration due to its enhanced complexing role. The absorption edge of the films almost underwent a blue shift with increasing ethylenediamine concentration, which was largely attributed to the quantum confinement effects caused by the small particle size of the polycrystalline ZnS films. Defect species and the corresponding strengths of the ZnS films were strongly affected by the ethylenediamine concentration.

  7. Synthesis of a new ONNO donor tetradentate schiff base ligand and binuclear Cu(II) complex: Quantum chemical, spectroscopic and photoluminescence investigations

    International Nuclear Information System (INIS)

    Sarıoğlu, Ahmet Oral; Ceylan, Ümit; Yalçın, Şerife Pınar; Sönmez, Mehmet; Ceyhan, Gökhan; Aygün, Muhittin

    2016-01-01

    The Schiff base compound 3,3′-(1,4-phenylimino)-bis-[1,3-bis-(4-methoxyphenyl) propan-1-one)], formulated as C 40 H 36 N 2 O 6, and its Cu(II) complex were synthesized and characterized by analytical analysis, various spectral techniques such as FT-IR, NMR, UV–vis, magnetic measurements and molar conductivity. Thermo gravimetric analysis (TGA and DTA) carried out to obtain information about its thermal stability. The molecular structure and spectroscopic properties of the ligand were obtained with FT-IR, 1 H and 13 C NMR, UV–vis investigations as experimentally and compared with theoretical results obtained from DFT/B3LYP/6-311++G(d,p) basis set. In addition to molecular calculations of the title compound, molecular electrostatic potential (MEP), dipole moments, atomic charges, HOMO–LUMO, NLO and NBO analysis were computed. The calculated results show that the optimized geometry can well reproduce the crystal structure parameters, and the theoretical vibrational frequencies, 1 H and 13 C NMR chemical shifts show good agreement with experimental values. Photoluminescence properties of the ligand and its Cu(II) complex were examined. - Highlights: • FT-IR and 1 H– 13 C NMR spectra were recorded and compared with the theoretical results. • The photoluminescence properties were studied. • NLO, NBO analysis of the molecule were studied. • HOMO and LUMO energies, MEP distribution of the molecule were calculated.

  8. Quantum chemical study, spectroscopic investigations, NBO and HOMO-LUMO analyses of 3-aminoquinoline (3AQ) and [Ag(3AQ)2(TCA)] complex (TCA = Trichloroacetate)

    Science.gov (United States)

    Soliman, Saied M.; Kassem, Taher S.; Badr, Ahmed M. A.; Abu Youssef, Morsy A.; Assem, Rania

    2014-09-01

    The new [Ag(3AQ)2(TCA)]; (3AQ = 3-aminoquinoline and TCA = Trichloroacetate) complex is synthesized and characterized using elemental analysis, FTIR, NMR and mass spectroscopy. The molecular geometry, vibrational frequencies, gauge-including atomic orbital (GIAO) 1H chemical shift values of the free and coordinated 3AQ in the ground state have been calculated by using DFT/B3LYP method. The TD-DFT results of the [Ag(3AQ)2(TCA)] complex showed a π-π* transition band at 240.3-242.6 nm (f = 0.1334-0.1348) which has longer wavelength and lower absorption intensity than that for the free 3AQ (233.2 nm, f = 0.3958). Dipole moment, polarizability and HOMO-LUMO gap values predicted better nonlinear optical properties (NLO) for the [Ag(3AQ)2(TCA)] than the 3AQ ligand. NBO analysis has been used to predict the most accurate Lewis structure of the studied molecules. The energies of the different intramolecular charge transfer (ICT) interactions within the studied molecules were estimated using second order perturbation theory.

  9. Chemical mass balance modeling for air quality analysis near a waste-to-energy facility in a complex urban area: Program design

    International Nuclear Information System (INIS)

    Wells, R.; Watson, J.

    1997-01-01

    This paper describes the design and implementation of an ambient monitoring and receptor modeling study to evaluate air quality impacts from a state-of-the-art municipal waste management facility in a major urban area. The Robbins Resource Recovery Facility (RRRF), located in the Chicago metropolitan area, processes municipal solid waste (MSW) to recover recyclables, process the residual waste to create refuse-derived fuel (RDF), and burns the RDF to reduce the residual waste volume and recover energy. The RRRF is cooperating with the Illinois Environmental Protection Agency (IEPA) and the Illinois Office of the Attorney General (OAG) to analyze air quality and facility impacts in the plant vicinity. An ambient monitoring program began one year before plant operation and will continue for five years after startup. Because the impacts of the RRRF are projected to be very low, and because the Chicago area includes a complex mix of existing industrial, commercial, and residential activity, the ambient data will be analyzed using Version 7.0 of the USEPA s Chemical Mass Balance (CMB) model to estimate the extent of the RRRF's impact on air quality in the area. The first year of pre-operational ambient data is currently under analysis. This paper describes the study design considerations, ambient monitoring program, emission data acquisition, background source data needs, and data analysis procedures developed to conduct CMB modeling in a complex industrialized area

  10. A lanthanide complex with dual biosensing properties: CEST (chemical exchange saturation transfer) and BIRDS (biosensor imaging of redundant deviation in shifts) with europium DOTA-tetraglycinate.

    Science.gov (United States)

    Coman, Daniel; Kiefer, Garry E; Rothman, Douglas L; Sherry, A Dean; Hyder, Fahmeed

    2011-12-01

    Responsive contrast agents (RCAs) composed of lanthanide(III) ion (Ln3R) complexes with a variety of1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (DOTA4S) derivatives have shown great potential as molecular imaging agents for MR. A variety of LnDOTA–tetraamide complexes have been demonstrated as RCAs for molecular imaging using chemical exchange saturation transfer (CEST). The CEST method detects proton exchange between bulk water and any exchangeable sites on the ligand itself or an inner sphere of bound water that is shifted by a paramagnetic Ln3R ion bound in the core of the macrocycle. It has also been shown that molecular imaging is possible when the RCA itself is observed (i.e. not its effect on bulk water) using a method called biosensor imaging of redundant deviation in shifts (BIRDS). The BIRDS method utilizes redundant information stored in the nonexchangeable proton resonances emanating from the paramagnetic RCA for ambient factors such as temperature and/or pH.Thus, CEST and BIRDS rely on exchangeable and nonexchangeable protons, respectively, for biosensing. We posited that it would be feasible to combine these two biosensing features into the same RCA (i.e. dual CEST and BIRDS properties). A complex between europium(III) ion (Eu3R) and DOTA–tetraglycinate [DOTA–(gly)S4] was used to demonstrate that its CEST characteristics are preserved, while its BIRDS properties are also detectable. The in vitro temperature sensitivity of EuDOTA–(gly)S4 was used to show that qualitative MR contrast with CEST can be calibrated using quantitative MR mapping with BIRDS, thereby enabling quantitative molecular imaging at high spatial resolution.

  11. Complex chemical composition of colored surface films formed from reactions of propanal in sulfuric acid at upper troposphere/lower stratosphere aerosol acidities.

    Science.gov (United States)

    Van Wyngarden, A L; Pérez-Montaño, S; Bui, J V H; Li, E S W; Nelson, T E; Ha, K T; Leong, L; Iraci, L T

    Particles in the upper troposphere and lower stratosphere (UT/LS) consist mostly of concentrated sulfuric acid (40-80 wt %) in water. However, airborne measurements have shown that these particles also contain a significant fraction of organic compounds of unknown chemical composition. Acid-catalyzed reactions of carbonyl species are believed to be responsible for significant transfer of gas phase organic species into tropospheric aerosols and are potentially more important at the high acidities characteristic of UT/LS particles. In this study, experiments combining sulfuric acid (H 2 SO 4 ) with propanal and with mixtures of propanal with glyoxal and/or methylglyoxal at acidities typical of UT/LS aerosols produced highly colored surface films (and solutions) that may have implications for aerosol properties. In order to identify the chemical processes responsible for the formation of the surface films, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and 1 H nuclear magnetic resonance (NMR) spectroscopies were used to analyze the chemical composition of the films. Films formed from propanal were a complex mixture of aldol condensation products, acetals and propanal itself. The major aldol condensation products were the dimer (2-methyl-2-pentenal) and 1,3,5-trimethylbenzene that was formed by cyclization of the linear aldol condensation trimer. Additionally, the strong visible absorption of the films indicates that higher-order aldol condensation products must also be present as minor species. The major acetal species were 2,4,6-triethyl-1,3,5-trioxane and longer-chain linear polyacetals which are likely to separate from the aqueous phase. Films formed on mixtures of propanal with glyoxal and/or methylglyoxal also showed evidence of products of cross-reactions. Since cross-reactions would be more likely than self-reactions under atmospheric conditions, similar reactions of aldehydes like propanal with common aerosol organic species like glyoxal

  12. Reversibility of female sterilization.

    Science.gov (United States)

    Siegler, A M; Hulka, J; Peretz, A

    1985-04-01

    The discussion considers the current status of reversibility of sterilization in the US and describes clinical and experimental efforts for developing techniques designed for reversibility. It focuses on regret following sterilization, reversal potential of current sterilization techniques, patient selection, current reversal techniques, results of sterilization procedures, experimental approaches to reversal of current techniques of sterilization, and sterilization procedures devised for reversibility, in humans and in animals. Request is the 1st stage of reversal, but a request for sterilization reversal (SR) does not always mean regret for a decision made at the time. Frequently it is a wish to restore fertility because life circumstances have changed after a sterilization that was ppropriate at the time it was performed. Schwyhart and Kutner reviewed 22 studies published between 1949-69 in which they found that the percentage of patients regretting the procedure ranged from 1.3-15%. Requests for reversal remain low in most countries, but if sterilization becomes a more popular method of contraception, requests will also increase. The ideal operation considered as a reversaible method of sterilization should include an easy, reliable outpatient method of tubal occlusion with miniml risk or patient discomfort that subsequently could be reversed without the need for a major surgical intervention. Endoscopic methods have progressed toward the 1st objective. A recent search of the literature uncovered few series of SR of more than 50 cases. The 767 operations found were analyzed with regard to pregnancy outcome. The precent of live births varied from 74-78.8%, and the occurance of tubal pregnancies ranged from 1.7-6.5%. All of the confounding variables in patient selection and small numbers of reported procedures preclude any conclusion about the different techniques or the number of operations that give a surgeon a level of expertise. Few authors classify their

  13. Quantum reverse hypercontractivity

    Energy Technology Data Exchange (ETDEWEB)

    Cubitt, Toby [Department of Computer Science, University College London, London, United Kingdom and Centre for Quantum Information and Foundations, DAMTP, University of Cambridge, Cambridge (United Kingdom); Kastoryano, Michael [NBIA, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Montanaro, Ashley [School of Mathematics, University of Bristol, Bristol (United Kingdom); Temme, Kristan [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-10-15

    We develop reverse versions of hypercontractive inequalities for quantum channels. By generalizing classical techniques, we prove a reverse hypercontractive inequality for tensor products of qubit depolarizing channels. We apply this to obtain a rapid mixing result for depolarizing noise applied to large subspaces and to prove bounds on a quantum generalization of non-interactive correlation distillation.

  14. Atrioventricular Pacemaker Lead Reversal

    Directory of Open Access Journals (Sweden)

    Mehmet K Aktas, MD

    2007-01-01

    Full Text Available During cardiac surgery temporary epicardial atrial and ventricular leads are placed in case cardiac pacing is required postoperatively. We present the first reported series of patients with reversal of atrioventricular electrodes in the temporary pacemaker without any consequent deleterious hemodynamic effect. We review the electrocardiographic findings and discuss the findings that lead to the discovery of atrioventricular lead reversal.

  15. FORMATION AND ELECTROCHEMICAL BEHAVIOUR OF POLYION COMPLEXES FOR ELECTROCHROMIC DISPLAY MATERIAL

    Institute of Scientific and Technical Information of China (English)

    WAN Guoxiang; WANG Bing; DENG Zhenghua; LUO Chunqiao

    1988-01-01

    Formation of intermacromolecular complexes containing viologen and electron-transfer reaction occurred on the electrode modified by the complex films were studied. Compositions and morphology of the complexes depend on the properties of polyanion and chemical environment of complexation. The analytical results of cyclic voltammetry (CV) and rotating disk voltammetry(RDV) indicated: (1) active sites of viologen in network of complexes transferred single electron reversibly; (2) the redox peak currents showed excellent symmetry and stability; (3) redox potentials were related to properties of polyanions, varying from -0.4 to -0.6V (vs. SCE). Electrochromic materials with different displaying colors could be obtained by changing the structure of polyviologen.

  16. The effect of crop sequences on soil microbial, chemical and physical indicators and its relationship with soybean sudden death syndrome (complex of Fusarium species

    Directory of Open Access Journals (Sweden)

    Carolina Perez-Brandan

    2013-12-01

    Full Text Available The effect of crop sequences on soil quality indicators and its relationship with sudden death syndrome (SDS, a complex of Fusarium species was evaluated by physical, chemical, biochemical and molecular techniques. Regarding physical aspects, soybean/maize and maize monoculture exhibited the highest stable aggregate level, with values 41% and 43% higher than in soybean monoculture, respectively, and 133% higher than in bean monoculture. Bulk density (BD was higher in soybean monoculture, being 4% higher than in bean monoculture. The chemical parameters organic matter, total N, P, K, Mg, Ca, and water holding capacity also indicated that soybean/maize and maize monoculture improved soil quality. Fungal and bacterial community fingerprints generated using Terminal Restriction Fragment Length Polymorphism analysis of intergenic transcribed spacer regions of rRNA genes and 16S rRNA genes, respectively, indicated a clear separation between the rotations. Fatty acid profiles evaluated by FAME showed that bean monoculture had higher biomass of Gram (+ bacteria and stress indicators than maize monoculture, while the soybean/maize system showed a significant increase in total microbial biomass (total FAMEs content in comparison with soybean and bean monoculture. The incidence of SDS (Fusarium crassistipitatum was markedly higher (15% under soybean monoculture than when soybean was grown in rotation with maize. In the present work, soil microbial properties were improved under soybean/maize relative to continuous soybean. The improvement of soil health was one of the main causes for the reduction of disease pressure and crop yield improvement due to the benefits that crop rotation produces for soil quality.

  17. Inhibition of precipitation of carbonate apatite by trisodium citrate analysed in base of the formation of chemical complexes in growth solution

    Energy Technology Data Exchange (ETDEWEB)

    Prywer, Jolanta, E-mail: jolanta.prywer@p.lodz.pl [Institute of Physics, Lodz University of Technology, ul. Wólczańska 219, 93-005 Łódź (Poland); Olszynski, Marcin [Institute of Physics, Lodz University of Technology, ul. Wólczańska 219, 93-005 Łódź (Poland); Mielniczek-Brzóska, Ewa [Institute of Chemistry, Environment Protection and Biotechnology, Jan Długosz University of Częstochowa, ul. Armii Krajowej 13/15, 42-200 Częstochowa (Poland)

    2015-11-15

    Effect of trisodium citrate on the precipitation of carbonate apatite is studied. The experimental series are performed in the solution of artificial urine. The investigations are related to infectious urinary stones formation as carbonate apatite is one of the main components of this kind of stones. To mimic a real infection in urinary tract the aqueous ammonia solution was added to the solution of artificial urine. The spectrophotometric results demonstrate that trisodium citrate increases induction time with respect to carbonate apatite formation and decreases the efficiency of carbonate apatite precipitation. The inhibitory effect of trisodium citrate on the precipitation of carbonate apatite is explained in base of chemical speciation analysis. Such an analysis demonstrates that the inhibitory effect is mainly related with the fact that trisodium citrate binds Ca{sup 2+} ions and causes the formation of CaCit{sup −} and Ca{sub 10}(PO{sub 4}){sub 6}CO{sub 3} complexes. Trisodium citrate binds Ca{sup 2+} ions in the range of pH from 6 to 9.5 for which carbonate apatite is favored to be formed. - Highlights: • Trisodium citrate (TC) increases induction time of carbonate apatite (CA) formation. • TC decreases the efficiency of CA precipitation. • The inhibitory effect of TC is explained in base of chemical speciation analysis. • The inhibitory effect is mainly related with the fact that TC binds Ca{sup 2+} ions. • TC binds Ca{sup 2+} ions in the range of pH from 6 to 9.5 for which CA is formed.

  18. The effect of crop sequences on soil microbial, chemical and physical indicators and its relationship with soybean sudden death syndrome (complex of Fusarium species)

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Brandan, C.; Arzeno, J. L.; Huidobro, J.; Conforto, C.; Grumberg, B.; Hilton, S.; Bending, G. D.; Meriles, J. M.; Vargas-Gil, S.

    2014-06-01

    The effect of crop sequences on soil quality indicators and its relationship with sudden death syndrome (SDS, a complex of Fusarium species) was evaluated by physical, chemical, biochemical and molecular techniques. Regarding physical aspects, soybean/maize and maize mono culture exhibited the highest stable aggregate level, with values 41% and 43% higher than in soybean mono culture, respectively, and 133% higher than in bean mono culture. Bulk density (BD) was higher in soybean monoculture, being 4% higher than in bean monoculture. The chemical parameters organic matter, total N, P, K, Mg, Ca, and water holding capacity also indicated that soybean/maize and maize monoculture improved soil quality. Fungal and bacterial community fingerprints generated using Terminal Restriction Fragment Length Polymorphism analysis of intergenic transcribed spacer regions of rRNA genes and 16S rRNA genes, respectively, indicated a clear separation between the rotations. Fatty acid profiles evaluated by FAME showed that bean monoculture had higher biomass of Gram (+) bacteria and stress indicators than maize monoculture, while the soybean/maize system showed a significant increase in total microbial biomass (total FAMEs content) in comparison with soybean and bean monoculture. The incidence of SDS (Fusarium crassistipitatum) was markedly higher (15%) under soybean monoculture than when soybean was grown in rotation with maize. In the present work, soil microbial properties were improved under soybean/maize relative to continuous soybean. The improvement of soil health was one of the main causes for the reduction of disease pressure and crop yield improvement due to the benefits that crop rotation produces for soil quality. (Author)

  19. Reversal of profound rocuronium neuromuscular blockade by sugammadex in anesthetized rhesus monkeys.

    NARCIS (Netherlands)

    Boer, H.D. de; Egmond, J. van; Pol, F. van de; Bom, A.; Booij, L.H.D.J.

    2006-01-01

    BACKGROUND: Reversal of neuromuscular blockade can be accomplished by chemical encapsulation of rocuronium by sugammadex, a synthetic gamma-cyclodextrin derivative. The current study determined the feasibility of reversal of rocuronium-induced profound neuromuscular blockade with sugammadex in the

  20. Repeatable Reverse Engineering with PANDA

    Science.gov (United States)

    2015-12-08

    necessary layout information for the Android 2.3 and 4.2 SDK kernels. See Section IV-C for an example of the kind of deep reverse engineering of Android apps ...code re-use and simplifying complex analysis development. We demonstrate PANDA’s effectiveness via a number of use cases, including enabling an old but...continue to function. 2) Identify critical vulnerabilities . 3) Understand the true purpose and actions of code. It is common for legacy code to stop

  1. Eriophorum angustifolium and Lolium perenne metabolic adaptations to metals- and metalloids-induced anomalies in the vicinity of a chemical industrial complex.

    Science.gov (United States)

    Anjum, Naser A; Ahmad, Iqbal; Rodrigues, Sónia M; Henriques, Bruno; Cruz, Nuno; Coelho, Cláudia; Pacheco, Mário; Duarte, Armando C; Pereira, Eduarda

    2013-01-01

    As plants constitute the foundation of the food chain, concerns have been raised about the possibility of toxic concentrations of metals and metalloids being transported from plants to the higher food chain strata. In this perspective, the use of important phytotoxicity endpoints may be of utmost significance in assessing the hazardous nature of metals and metalloids and also in developing ecological soil screening levels. The current study aimed to investigate the role of glutathione (GSH) and its associated enzymes in the metabolic adaptation of two grass species namely Eriophorum angustifolium Honck. and Lolium perenne L. to metals and metalloids stress in the vicinity of a chemical industrial complex (Estarreja, Portugal). Soil and plant samples were collected from contaminated (C) and non-contaminated (reference, R) sites, respectively, near and away from the Estarreja Chemical Complex, Portugal. Soils (from 0 to 10 and 10 to 20 cm depths) were analyzed for pH, organic carbon, and metals and metalloids concentrations. Plant samples were processed fresh for physiological and biochemical estimations, while oven-dried plant samples were used for metals and metalloids determinations following standard methodologies. Both soils and plants from the industrial area exhibited differential concentrations of major metals and metalloids including As, Cu, Hg, Pb, and Zn. In particular, L. perenne shoot displayed significantly higher and lower concentrations of Pb and As, respectively at contaminated site (vs. E. angustifolium). Irrespective of sites, L. perenne shoot exhibited significantly higher total GSH pool, oxidized glutathione (GSSG) and oxidized protein (vs. E. angustifolium). Additionally, severe damages to photosynthetic pigments, proteins, cellular membrane integrity (in terms of electrolyte leakage), and lipid peroxidation were also perceptible in L. perenne shoot. Contrarily, irrespective of the sites, activities of catalase and GSH-regenerating enzyme, GSH

  2. DNA-Encoded Dynamic Combinatorial Chemical Libraries.

    Science.gov (United States)

    Reddavide, Francesco V; Lin, Weilin; Lehnert, Sarah; Zhang, Yixin

    2015-06-26

    Dynamic combinatorial chemistry (DCC) explores the thermodynamic equilibrium of reversible reactions. Its application in the discovery of protein binders is largely limited by difficulties in the analysis of complex reaction mixtures. DNA-encoded chemical library (DECL) technology allows the selection of binders from a mixture of up to billions of different compounds; however, experimental results often show low a signal-to-noise ratio and poor correlation between enrichment factor and binding affinity. Herein we describe the design and application of DNA-encoded dynamic combinatorial chemical libraries (EDCCLs). Our experiments have shown that the EDCCL approach can be used not only to convert monovalent binders into high-affinity bivalent binders, but also to cause remarkably enhanced enrichment of potent bivalent binders by driving their in situ synthesis. We also demonstrate the application of EDCCLs in DNA-templated chemical reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Reversible polymer networks containing covalent and hydrogen bonding interactions

    NARCIS (Netherlands)

    Araya-Hermosilla, R.; Broekhuis, A.A.; Picchioni, F.

    Thermally reversible polymers with relatively high glass transition temperatures (T-g) are difficult to prepare but very interesting from an application point of view. In this work we present a novel reversible thermoset with tunable T-g based on chemical modification of aliphatic polyketones (PM)

  4. Investigations of the uptake of transuranic radionuclides by humic and fulvic acids chemically immobilized on silica gel and their competitive release by complexing agents

    International Nuclear Information System (INIS)

    Bulman, R.A.; Szabo, G.; Clayton, R.F.; Clayton, C.R.

    1998-01-01

    The chemistry of the interactions of transuranic elements (TUs) with humic substances needs to be understood so that humate-mediated movement of transuranic radionuclides through the environment can be predicted. This paper reports the chemical immobilization on silica gel of humic and fulvic acids and evaluates the potential of these new materials for the retention of Pu and Am. In addition to the preparation of the foregoing immobilized humic substances, other low molecular weight metal-binding ligands have also been immobilized on silica gel to investigate the binding sites for transuranic elements (TUs) in humic substances. The X-ray photoelectron spectra (XPS) of Th(IV) complexed by humic acid and the immobilized humic acid are similar thus it appears that immobilization of humic acid does not generate any configurational changes in the Th(IV)-binding sites of the macromolecule. A variety of chelating agents partly mobilize these TUs sorbed on the solid phases. A batch method was used to determine the distribution coefficients (R d ) of Pu and Am between the silica gels and aqueous solutions of phosphate and citrate. The effects of the immobilized ligands, the anions and pH in the solution on sorption were assessed. Distributed coefficients (R d ) for the uptake of Pu and Am by these prepared solid phases are, in some cases, of a similar order of magnitude as those determined for soil and particles suspended in terrestrial surface waters

  5. An algebra of reversible computation.

    Science.gov (United States)

    Wang, Yong

    2016-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules: basic reversible processes algebra, algebra of reversible communicating processes, recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  6. Optical reversible programmable Boolean logic unit.

    Science.gov (United States)

    Chattopadhyay, Tanay

    2012-07-20

    Computing with reversibility is the only way to avoid dissipation of energy associated with bit erase. So, a reversible microprocessor is required for future computing. In this paper, a design of a simple all-optical reversible programmable processor is proposed using a polarizing beam splitter, liquid crystal-phase spatial light modulators, a half-wave plate, and plane mirrors. This circuit can perform 16 logical operations according to three programming inputs. Also, inputs can be easily recovered from the outputs. It is named the "reversible programmable Boolean logic unit (RPBLU)." The logic unit is the basic building block of many complex computational operations. Hence the design is important in sense. Two orthogonally polarized lights are defined here as two logical states, respectively.

  7. Sex reversal in vertebrates

    OpenAIRE

    2016-01-01

    This special topic issue of Sexual Development gives an overview of sex reversal in vertebrates, from fishes naturally changing their sex, to rodents escaping the mammalian SRY-determining system. It offers eight up-to-date reviews on specific subjects in sex reversal, considering fishes, amphibians, reptiles, birds, marsupials, and placental mammals, including humans. The broad scope of represented animals makes this ideal for students and researchers, especially those interested in the...

  8. Reversibility: An Engineer's Point of View

    Energy Technology Data Exchange (ETDEWEB)

    Berest, Pierre [LMS, ecole Polytechnique (France)

    2012-07-01

    Reversibility is the most consistent option in a democratic country. However reversibility may also have several drawbacks which must be identified and mitigated. Reversibility of a geological repository is a relatively new idea in France. The 1991 law dedicated to nuclear waste management considered reversibility as a possible option. Fifteen years later, the 2006 law mandated that a deep repository must be reversible and that the exact content of this notion should be defined by a new law to be discussed by the Parliament in 2015. Reversibility was not a concern put forward by engineers. It clearly originated from a societal demand sponsored and formulated by the Parliament. Since 1991, the exact meaning of this mandate progressively became more precise. In the early days, reversibility meant the technical and financial capability to retrieve the wastes from the repository, at least for some period of time after being emplaced. Progressively, a broader definition, suggested by Andra, was accepted: reversibility also means that a disposal facility should be operated in such a way that a stepwise decision-making process is possible. At each step, society must be able to decide to proceed to the next step, to pause or to reverse a step. Several benefits can be expected from a reversible repository. Some technical safety concerns may be only recognised after waste emplacement. Radioactive wastes may become a resource whose recoverability is desirable. Regulations may change, alternative waste treatment or better disposal techniques may be developed, or the need to modify a component of the facility may arise. Looking back at how chemical or domestic wastes were managed some 50 years ago easily underscores that it is not unreasonable to hope for significant advances in the future. For scientists and engineers, reversibility proves to have several other merits. To design and build a good repository, time is needed. The operator of a mine or of an oil field knows that

  9. Communication complexity and information complexity

    Science.gov (United States)

    Pankratov, Denis

    complexity of two of the most studied functions in the communication complexity literature: Gap Hamming Distance (GHD) and Inner Product mod 2 (IP). In our first result we affirm the conjecture that the information complexity of GHD is linear even under the uniform distribution. This strengthens the O(n) bound shown by Kerenidis et al. (2012) and answers an open problem by Chakrabarti et al. (2012). We also prove that the information complexity of IP is arbitrarily close to the trivial upper bound n as the permitted error tends to zero, again strengthening the O(n) lower bound proved by Braverman and Weinstein (2011). More importantly, our proofs demonstrate that self-reducibility makes the connection between information complexity and communication complexity lower bounds a two-way connection. Whereas numerous results in the past used information complexity techniques to derive new communication complexity lower bounds, we explore a generic way, in which communication complexity lower bounds imply information complexity lower bounds in a black-box manner. In the third contribution we consider the roles that private and public randomness play in the definition of information complexity. In communication complexity, private randomness can be trivially simulated by public randomness. Moreover, the communication cost of simulating public randomness with private randomness is well understood due to Newman's theorem (1991). In information complexity, the roles of public and private randomness are reversed: public randomness can be trivially simulated by private randomness. However, the information cost of simulating private randomness with public randomness is not understood. We show that protocols that use only public randomness admit a rather strong compression. In particular, efficient simulation of private randomness by public randomness would imply a version of a direct sum theorem in the setting of communication complexity. This establishes a yet another connection between

  10. The binding of platinum hexahalides (Cl, Br and I) to hen egg-white lysozyme and the chemical transformation of the PtI{sub 6} octahedral complex to a PtI{sub 3} moiety bound to His15

    Energy Technology Data Exchange (ETDEWEB)

    Tanley, Simon W. M.; Starkey, Laurina-Victoria; Lamplough, Lucinda; Kaenket, Surasek; Helliwell, John R., E-mail: john.helliwell@manchester.ac.uk [University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom)

    2014-08-29

    The platinum hexahalides have an octahedral arrangement of six halogen atoms bound to a Pt centre, thus having an octahedral shape that could prove to be useful in interpreting poor electron-density maps. In a detailed characterization, PtI{sub 6} chemically transformed to a square-planar PtI{sub 3} complex bound to the N{sup δ} atom of His15 of HEWL was also observed, which was not observed for PtBr{sub 6} or PtCl{sub 6}. This study examines the binding and chemical stability of the platinum hexahalides K{sub 2}PtCl{sub 6}, K{sub 2}PtBr{sub 6} and K{sub 2}PtI{sub 6} when soaked into pre-grown hen egg-white lysozyme (HEWL) crystals as the protein host. Direct comparison of the iodo complex with the chloro and bromo complexes shows that the iodo complex is partly chemically transformed to a square-planar PtI{sub 3} complex bound to the N{sup δ} atom of His15, a chemical behaviour that is not exhibited by the chloro or bromo complexes. Each complex does, however, bind to HEWL in its octahedral form either at one site (PtI{sub 6}) or at two sites (PtBr{sub 6} and PtCl{sub 6}). As heavy-atom derivatives of a protein, the octahedral shape of the hexahalides could be helpful in cases of difficult-to-interpret electron-density maps as they would be recognisable ‘objects’.

  11. On thermodynamic and microscopic reversibility

    International Nuclear Information System (INIS)

    Crooks, Gavin E

    2011-01-01

    The word 'reversible' has two (apparently) distinct applications in statistical thermodynamics. A thermodynamically reversible process indicates an experimental protocol for which the entropy change is zero, whereas the principle of microscopic reversibility asserts that the probability of any trajectory of a system through phase space equals that of the time reversed trajectory. However, these two terms are actually synonymous: a thermodynamically reversible process is microscopically reversible, and vice versa

  12. Final Technical Report: Metal—Organic Surface Catalyst for Low-temperature Methane Oxidation: Bi-functional Union of Metal—Organic Complex and Chemically Complementary Surface

    Energy Technology Data Exchange (ETDEWEB)

    Tait, Steven L. [Indiana Univ., Bloomington, IN (United States)

    2016-10-01

    Stabilization and chemical control of transition metal centers is a critical problem in the advancement of heterogeneous catalysts to next-generation catalysts that exhibit high levels of selectivity, while maintaining strong activity and facile catalyst recycling. Supported metal nanoparticle catalysts typically suffer from having a wide range of metal sites with different coordination numbers and varying chemistry. This project is exploring new possibilities in catalysis by combining features of homogeneous catalysts with those of heterogeneous catalysts to develop new, bi-functional systems. The systems are more complex than traditional heterogeneous catalysts in that they utilize sequential active sites to accomplish the desired overall reaction. The interaction of metal—organic catalysts with surface supports and their interactions with reactants to enable the catalysis of critical reactions at lower temperatures are at the focus of this study. Our work targets key fundamental chemistry problems. How do the metal—organic complexes interact with the surface? Can those metal center sites be tuned for selectivity and activity as they are in the homogeneous system by ligand design? What steps are necessary to enable a cooperative chemistry to occur and open opportunities for bi-functional catalyst systems? Study of these systems will develop the concept of bringing together the advantages of heterogeneous catalysis with those of homogeneous catalysis, and take this a step further by pursuing the objective of a bi-functional system. The use of metal-organic complexes in surface catalysts is therefore of interest to create well-defined and highly regular single-site centers. While these are not likely to be stable in the high temperature environments (> 300 °C) typical of industrial heterogeneous catalysts, they could be applied in moderate temperature reactions (100-300 °C), made feasible by lowering reaction temperatures by better catalyst control. They also

  13. A framework for the use of single-chemical transcriptomics data in predicting the hazards associated with complex mixtures of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Labib, Sarah; Williams, Andrew; Kuo, Byron; Yauk, Carole L; White, Paul A; Halappanavar, Sabina

    2017-07-01

    The assumption of additivity applied in the risk assessment of environmental mixtures containing carcinogenic polycyclic aromatic hydrocarbons (PAHs) was investigated using transcriptomics. MutaTMMouse were gavaged for 28 days with three doses of eight individual PAHs, two defined mixtures of PAHs, or coal tar, an environmentally ubiquitous complex mixture of PAHs. Microarrays were used to identify differentially expressed genes (DEGs) in lung tissue collected 3 days post-exposure. Cancer-related pathways perturbed by the individual or mixtures of PAHs were identified, and dose-response modeling of the DEGs was conducted to calculate gene/pathway benchmark doses (BMDs). Individual PAH-induced pathway perturbations (the median gene expression changes for all genes in a pathway relative to controls) and pathway BMDs were applied to models of additivity [i.e., concentration addition (CA), generalized concentration addition (GCA), and independent action (IA)] to generate predicted pathway-specific dose-response curves for each PAH mixture. The predicted and observed pathway dose-response curves were compared to assess the sensitivity of different additivity models. Transcriptomics-based additivity calculation showed that IA accurately predicted the pathway perturbations induced by all mixtures of PAHs. CA did not support the additivity assumption for the defined mixtures; however, GCA improved the CA predictions. Moreover, pathway BMDs derived for coal tar were comparable to BMDs derived from previously published coal tar-induced mouse lung tumor incidence data. These results suggest that in the absence of tumor incidence data, individual chemical-induced transcriptomics changes associated with cancer can be used to investigate the assumption of additivity and to predict the carcinogenic potential of a mixture.

  14. Economic impact of reversion

    International Nuclear Information System (INIS)

    2005-01-01

    Estimations of the Norwegian hydropower production and various reversion models' market value have been made. The value of the Norwegian hydropower production until 01.01.2007 is estimated to about Nok 289 billion after taxes, or about 2,42 Nok/kWh medium production, given an expected future electricity price of around 0,25 Nok/kWh and a discount rate at 6,5 percent in nominal terms after taxes. The estimate is slightly above the level of prices for Norwegian hydropower plants in the last 8-10 years. The value of reversion in private plants which today have a limited licence time is estimated to Nok 5,5 billion. The value of reversion in public-owned Norwegian hydropower plants are about Nok 21 billion with a 60 year licence period from 01.01.2007, and about 12 billion for 75 years (ml)

  15. Reversible deep disposal

    International Nuclear Information System (INIS)

    2009-10-01

    This presentation, given by the national agency of radioactive waste management (ANDRA) at the meeting of October 8, 2009 of the high committee for the nuclear safety transparency and information (HCTISN), describes the concept of deep reversible disposal for high level/long living radioactive wastes, as considered by the ANDRA in the framework of the program law of June 28, 2006 about the sustainable management of radioactive materials and wastes. The document presents the social and political reasons of reversibility, the technical means considered (containers, disposal cavities, monitoring system, test facilities and industrial prototypes), the decisional process (progressive development and blocked off of the facility, public information and debate). (J.S.)

  16. Post-partum posterior reversible encephalopathy syndrome

    DEFF Research Database (Denmark)

    Aaen, Anne Albers; Jeppesen, Jørgen; Obaid, Hayder

    2015-01-01

    Posterior reversible encephalopathy syndrome (PRES) is a complex clinical condition with vasogenic subcortical oedema caused by hypertension. Oedema is often seen on magnetic resonance imaging. The wide clinical spectrum ranges from headaches to vision loss and even death. Early diagnosis...... and treatment is important for the reversibility of the condition. In this case report we emphasize the importance of blood pressure control in a post-partum woman, who had a rather complicated pregnancy. The symptoms of PRES were not recognized immediately because of failure to use and acknowledge a blood...

  17. Research regarding reverse engineering for aircraft components

    Directory of Open Access Journals (Sweden)

    Udroiu Razvan

    2017-01-01

    Full Text Available Reverse engineering is a useful technique used in manufacturing and design process of new components. In aerospace industry new components can be developed, based on existing components without technical Computer Aided Design (CAD data, in order to reduce the development cycle of new products. This paper proposes a methodology wherein the CAD model of turbine blade can be build using computer aided reverse engineering technique utilising a 5 axis Coordinate Measuring Machine (CMM. The proposed methodology uses a scanning strategy by features, followed by a design methodology for 3D modelling of complex shapes.

  18. Post-partum posterior reversible encephalopathy syndrome

    DEFF Research Database (Denmark)

    Aaen, Anne Albers; Jeppesen, Jørgen; Obaid, Hayder

    2015-01-01

    and treatment is important for the reversibility of the condition. In this case report we emphasize the importance of blood pressure control in a post-partum woman, who had a rather complicated pregnancy. The symptoms of PRES were not recognized immediately because of failure to use and acknowledge a blood......Posterior reversible encephalopathy syndrome (PRES) is a complex clinical condition with vasogenic subcortical oedema caused by hypertension. Oedema is often seen on magnetic resonance imaging. The wide clinical spectrum ranges from headaches to vision loss and even death. Early diagnosis...

  19. [Post-partum posterior reversible encephalopathy syndrome].

    Science.gov (United States)

    Aaen, Anne Albers; Jeppesen, Jørgen; Obaid, Hayder; Bülow, Hans Henrik

    2015-11-23

    Posterior reversible encephalopathy syndrome (PRES) is a complex clinical condition with vasogenic subcortical oedema caused by hypertension. Oedema is often seen on magnetic resonance imaging. The wide clinical spectrum ranges from headaches to vision loss and even death. Early diagnosis and treatment is important for the reversibility of the condition. In this case report we emphasize the importance of blood pressure control in a post-partum woman, who had a rather complicated pregnancy. The symptoms of PRES were not recognized immediately because of failure to use and acknowledge a blood pressure test.

  20. Economic advantages to optimising chemical products in pre-treatment in reverse osmosis desalination plants; Ventajas economicas al optimizar los productos quimicos en el pretratamiento de plantas desaladoras por osmosis inversa

    Energy Technology Data Exchange (ETDEWEB)

    Munoz Elguera, A.; Alday Ansola, J.; Perez Baez, S. O.

    2001-07-01

    This article reports the results of a process of optimising the dosage of Sodium hypochlorite and Metabisulphite, performed on sea water in the pre-treatment division of the Las Palmas III reverse osmosis desalination plant, currently operated by Empresa Mixta de Aguas de las Palmas (EMALSA), responsible for providing drinking water to more than 400.000 people in the city of Las Palmas, capital of Grand Canary Island. The results of this optimisation process, contrary to the opinion of the operators of the plant, after reducing the amount of Metabisulphite normally used in the plant by 70%, and Sodium hypochlorite by 30%, there were no adverse effects on the microbiological quality of the sea water. Moreover, the performance of the membranes was improved (bad odors disappeared, along with organic material sediments, etc.). (Author) 9 refs.

  1. A computer model for one-dimensional mass and energy transport in and around chemically reacting particles, including complex gas-phase chemistry, multicomponent molecular diffusion, surface evaporation, and heterogeneous reaction

    Science.gov (United States)

    Cho, S. Y.; Yetter, R. A.; Dryer, F. L.

    1992-01-01

    Various chemically reacting flow problems highlighting chemical and physical fundamentals rather than flow geometry are presently investigated by means of a comprehensive mathematical model that incorporates multicomponent molecular diffusion, complex chemistry, and heterogeneous processes, in the interest of obtaining sensitivity-related information. The sensitivity equations were decoupled from those of the model, and then integrated one time-step behind the integration of the model equations, and analytical Jacobian matrices were applied to improve the accuracy of sensitivity coefficients that are calculated together with model solutions.

  2. Thermosensory reversal effect quantified

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kappers, A.M.L.

    2008-01-01

    At room temperature, some materials feel colder than others due to differences in thermal conductivity, heat capacity and geometry. When the ambient temperature is well above skin temperature, the roles of 'cold' and 'warm' materials are reversed. In this paper, this effect is quantified by

  3. Thermosensory reversal effect quantified

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kappers, A.M.L.

    2008-01-01

    At room temperature, some materials feel colder than others due to differences in thermal conductivity, heat capacity and geometry. When the ambient temperature is well above skin temperature, the roles of ‘cold’ and ‘warm’ materials are reversed. In this paper, this effect is quantified by

  4. Time reversal communication system

    Science.gov (United States)

    Candy, James V.; Meyer, Alan W.

    2008-12-02

    A system of transmitting a signal through a channel medium comprises digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. The channel medium may be air, earth, water, tissue, metal, and/or non-metal.

  5. Engineering Encounters: Reverse Engineering

    Science.gov (United States)

    McGowan, Veronica Cassone; Ventura, Marcia; Bell, Philip

    2017-01-01

    This column presents ideas and techniques to enhance your science teaching. This month's issue shares information on how students' everyday experiences can support science learning through engineering design. In this article, the authors outline a reverse-engineering model of instruction and describe one example of how it looked in our fifth-grade…

  6. Sex Reversal in Birds.

    Science.gov (United States)

    Major, Andrew T; Smith, Craig A

    2016-01-01

    Sexual differentiation in birds is controlled genetically as in mammals, although the sex chromosomes are different. Males have a ZZ sex chromosome constitution, while females are ZW. Gene(s) on the sex chromosomes must initiate gonadal sex differentiation during embryonic life, inducing paired testes in ZZ individuals and unilateral ovaries in ZW individuals. The traditional view of avian sexual differentiation aligns with that expounded for other vertebrates; upon sexual differentiation, the gonads secrete sex steroid hormones that masculinise or feminise the rest of the body. However, recent studies on naturally occurring or experimentally induced avian sex reversal suggest a significant role for direct genetic factors, in addition to sex hormones, in regulating sexual differentiation of the soma in birds. This review will provide an overview of sex determination in birds and both naturally and experimentally induced sex reversal, with emphasis on the key role of oestrogen. We then consider how recent studies on sex reversal and gynandromorphic birds (half male:half female) are shaping our understanding of sexual differentiation in avians and in vertebrates more broadly. Current evidence shows that sexual differentiation in birds is a mix of direct genetic and hormonal mechanisms. Perturbation of either of these components may lead to sex reversal. © 2016 S. Karger AG, Basel.

  7. Elastomers with Reversible Nanoporosity

    DEFF Research Database (Denmark)

    Szewczykowski, Piotr Przemyslaw; Andersen, K.; Schulte, Lars

    2009-01-01

    nanostructure and displays liquid-filled cavities. Upon several cycles of swelling and drying the cavities open and close in a reversible fashion. When exposed to a nonsolvent, the material remains collapsed. This discriminating behavior of liquid-material interaction holds potential for the use...

  8. Thermodynamic reversibility and irreversibility of the reverse transformation in stabilized Cu-Zn-Al martensite

    International Nuclear Information System (INIS)

    Kustov, S.; Corro, M.; Pons, J.; Cesari, E.; Van Humbeeck, J.

    2006-01-01

    It has been shown that both pinning- (mechanical) and reordering-induced (chemical) stabilization components contribute to the overall stabilization effect. An algorithm has been developed for quantitative analysis of the chemical and mechanical stabilization components, using routine calorimetry results. The basic idea underlying this algorithm is that chemical and mechanical stabilization components stem, respectively, from the factors, affecting thermodynamically reversible and irreversible factors during the first reverse transformation of the stabilized martensite. On a thermodynamical level, application of the suggested algorithm has been illustrated using experimental calorimetry results for a Cu-Zn-Al alloy. Here we report analysis of pinning and reordering processes on a microscopic scale, using experimental data on non-linear anelasticity in the same Cu-Zn-Al alloy to track different spatial and temporal localization of these processes during martensite ageing

  9. Dual-directional regulation of drug permeating amount by combining the technique of ion-pair complexation with chemical enhancers for the synchronous permeation of indapamide and bisoprolol in their compound patch through rabbit skin.

    Science.gov (United States)

    Song, Wenting; Cun, Dongmei; Quan, Peng; Liu, Nannan; Chen, Yang; Cui, Hongxia; Xiang, Rongwu; Fang, Liang

    2015-04-01

    To achieve the synchronous skin permeation of indapamide (IND) and bisoprolol (BSP) in their compound patch, the techniques of ion-pair complexation and chemical enhancers were combined to dual-directionally regulate drug permeating amounts. Ion-pair complexes of BSP and various organic acids were formed by the technique of ion-pair complexation. Among the complexes formed, bisoprolol tartrate (BSP.T) down-regulated the permeating amount of BSP to the same extent as that of IND. Then, to simultaneously up-regulate the amounts of the two drugs, an enhancer combination of 15.8% Span80 (SP), 6.0% Azone (AZ) and 2.2% N-methyl pyrrolidone (NMP) was obtained by central composite design and exhibited an outstanding and simultaneous enhancement on IND and BSP with enhancing ratio (ER) of 4.52 and 3.49, respectively. The effect of the dual-directional regulation was evaluated by in vitro permeation experiments and in vivo pharmacokinetic studies. For IND and BSP, their observed permeation profiles were comparable and their MAT (mean absorption time) showed no significant difference, which both demonstrated these two drugs achieved the synchronous skin permeation in their compound patch by the dual-directional regulation strategy of combining the technique of ion-pair complexation with chemical enhancers. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Ferric and cobaltous hydroacid complexes for forward osmosis (FO) processes

    KAUST Repository

    Ge, Qingchun; Fu, Fengjiang; Chung, Neal Tai-Shung

    2014-01-01

    Cupric and ferric hydroacid complexes have proven their advantages as draw solutes in forward osmosis in terms of high water fluxes, negligible reverse solute fluxes and easy recovery (Ge and Chung, 2013. Hydroacid complexes: A new class of draw solutes to promote forward osmosis (FO) processes. Chemical Communications 49, 8471-8473.). In this study, cobaltous hydroacid complexes were explored as draw solutes and compared with the ferric hydroacid complex to study the factors influencing their FO performance. The solutions of the cobaltous complexes produce high osmotic pressures due to the presence of abundant hydrophilic groups. These solutes are able to dissociate and form a multi-charged anion and Na+ cations in water. In addition, these complexes have expanded structures which lead to negligible reverse solute fluxes and provide relatively easy approaches in regeneration. These characteristics make the newly synthesized cobaltous complexes appropriate as draw solutes. The FO performance of the cobaltous and ferric-citric acid (Fe-CA) complexes were evaluated respectively through cellulose acetate membranes, thin-film composite membranes fabricated on polyethersulfone supports (referred as TFC-PES), and polybenzimidazole and PES dual-layer (referred as PBI/PES) hollow fiber membranes. Under the conditions of DI water as the feed and facing the support layer of TFC-PES FO membranes (PRO mode), draw solutions at 2.0M produced relatively high water fluxes of 39-48 LMH (Lm-2hr-1) with negligible reverse solute fluxes. A water flux of 17.4 LMH was achieved when model seawater of 3.5wt.% NaCl replaced DI water as the feed and 2.0M Fe-CA as the draw solution under the same conditions. The performance of these hydroacid complexes surpasses those of the synthetic draw solutes developed in recent years. This observation, along with the relatively easy regeneration, makes these complexes very promising as a novel class of draw solutes. © 2014 Elsevier Ltd.

  11. Ferric and cobaltous hydroacid complexes for forward osmosis (FO) processes

    KAUST Repository

    Ge, Qingchun

    2014-07-01

    Cupric and ferric hydroacid complexes have proven their advantages as draw solutes in forward osmosis in terms of high water fluxes, negligible reverse solute fluxes and easy recovery (Ge and Chung, 2013. Hydroacid complexes: A new class of draw solutes to promote forward osmosis (FO) processes. Chemical Communications 49, 8471-8473.). In this study, cobaltous hydroacid complexes were explored as draw solutes and compared with the ferric hydroacid complex to study the factors influencing their FO performance. The solutions of the cobaltous complexes produce high osmotic pressures due to the presence of abundant hydrophilic groups. These solutes are able to dissociate and form a multi-charged anion and Na+ cations in water. In addition, these complexes have expanded structures which lead to negligible reverse solute fluxes and provide relatively easy approaches in regeneration. These characteristics make the newly synthesized cobaltous complexes appropriate as draw solutes. The FO performance of the cobaltous and ferric-citric acid (Fe-CA) complexes were evaluated respectively through cellulose acetate membranes, thin-film composite membranes fabricated on polyethersulfone supports (referred as TFC-PES), and polybenzimidazole and PES dual-layer (referred as PBI/PES) hollow fiber membranes. Under the conditions of DI water as the feed and facing the support layer of TFC-PES FO membranes (PRO mode), draw solutions at 2.0M produced relatively high water fluxes of 39-48 LMH (Lm-2hr-1) with negligible reverse solute fluxes. A water flux of 17.4 LMH was achieved when model seawater of 3.5wt.% NaCl replaced DI water as the feed and 2.0M Fe-CA as the draw solution under the same conditions. The performance of these hydroacid complexes surpasses those of the synthetic draw solutes developed in recent years. This observation, along with the relatively easy regeneration, makes these complexes very promising as a novel class of draw solutes. © 2014 Elsevier Ltd.

  12. Chemical speciation of Pb(II, Cd(II, Hg(II, Co(II, Ni(II, Cu(II and Zn(II binary complexes of l-methionine in 1,2-propanediol-water mixtures

    Directory of Open Access Journals (Sweden)

    M. Padma Latha

    2007-04-01

    Full Text Available Chemical speciation of Pb(II, Cd(II, Hg(II, Co(II, Ni(II, Cu(II and Zn(II complexes of L-methionine in 0.0-60 % v/v 1,2-propanediol-water mixtures maintaining an ionic strength of 0.16 M at 303 K has been studied pH metrically. The active forms of ligand are LH2+, LH and L-. The predominant species detected are ML, MLH, ML2, ML2H, ML2H2 and MLOH. Models containing different numbers of species were refined by using the computer program MINIQUAD 75. The best-fit chemical models were arrived at based on statistical parameters. The trend in variation of complex stability constants with change in the dielectric constant of the medium is explained on the basis of electrostatic and non-electrostatic forces.

  13. Reverse osmosis influence over the content of metals and organic acids in low alcoholic beverages

    Directory of Open Access Journals (Sweden)

    Andrieş Mitică Tiberiu

    2017-01-01

    Full Text Available Wine is defined as an alcoholic beverage resulted from fermentation of grape must, having ethanol content higher than 8.5% (v/v. Wine consumption has health benefits related to the high concentration of polyphenolic compounds with antioxidant activity and cardiovascular protection effects. However, the alcohol content restricts wine consumption, but wines with low-alcohol content can be obtained with the help of the dealcoholisation process, after it was produced through alcoholic fermentation. The purpose of this work is to evaluate the organic acid concentration, metal content and other physical-chemical parameters of low alcoholic beverages obtained from grape must by a process which involves reverse osmosis, mixing in a variable ratio the permeate and concentrate and then fermentation. For the experiments, a Muscat Ottonel grape must from Iaşi vineyard was used. There were ten variants of beverages (wines with low alcoholic concentration, by mixing known quantities of the two phases resulting from the reverse osmosis process. These beverages (wines had an alcoholic concentration starting from 2.5% (v/v in the first variant, up to 7% (v/v in the tenth variant. Alcoholic concentration varies for each variant by 0.5% (v/v. After fermentation in 50 L stainless steel tanks, the samples were filtered with 0.45μm sterile membrane and bottled in 0.75 L glass bottles. After 2 months of storage at constant temperature, the beverage samples were analyzed to determine the metal content (AAS method, organic acids concentration (HPLC method, and other physical-chemical characteristics (OIV standard methods. The results obtained indicate that the very complex physical-chemical composition of the low alcoholic beverages analyzed is influenced by the specific chemical composition of a given grape must, as well as by the use of products obtained from reverse osmosis.

  14. Lanthanide ion (III) complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate for dual biosensing of pH with chemical exchange saturation transfer (CEST) and biosensor imaging of redundant deviation in shifts (BIRDS).

    Science.gov (United States)

    Huang, Yuegao; Coman, Daniel; Ali, Meser M; Hyder, Fahmeed

    2015-01-01

    Relaxivity-based magnetic resonance of phosphonated ligands chelated with gadolinium (Gd(3+)) shows promise for pH imaging. However instead of monitoring the paramagnetic effect of lanthanide complexes on the relaxivity of water protons, biosensor (or molecular) imaging with magnetic resonance is also possible by detecting either the nonexchangeable or the exchangeable protons on the lanthanide complexes themselves. The nonexchangeable pr