WorldWideScience

Sample records for superconducting chemical compounds

  1. Physical and chemical studies of superconduction properties of the intercalation compounds

    International Nuclear Information System (INIS)

    Eder, F.X.; Lerf, A.

    1980-01-01

    The superconducting properties of the intercalation compounds of layered dichalcogenides were studied. Our studies were concerned mainly to the alkali metal intercalation derivatives of TaS 2 and NbS 2 , and later on extended to the molecule intercalation compounds. The main difficulties with this class of superconductors result from varying material properties; these are therefore the subject of broad intensity in our investigations. The results received on the physical and chemical properties of the intercalation compounds is utilized for a phenomenological description of the factors mainly determining there superconducting properties. (orig.) [de

  2. Superconductivity in graphite intercalation compounds

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Robert P. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Weller, Thomas E.; Howard, Christopher A. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Dean, Mark P.M. [Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Rahnejat, Kaveh C. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Saxena, Siddharth S. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Ellerby, Mark, E-mail: mark.ellerby@ucl.ac.uk [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom)

    2015-07-15

    Highlights: • Historical background of graphite intercalates. • Superconductivity in graphite intercalates and its place in the field of superconductivity. • Recent developments. • Relevant modeling of superconductivity in graphite intercalates. • Interpretations that pertain and questions that remain. - Abstract: The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC{sub 6} and YbC{sub 6} in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

  3. Synthesis of molybdenum carbide superconducting compounds by microwave-plasma chemical vapor deposition

    Science.gov (United States)

    Zhao, Hongyang; Cai, Kang; Ma, Zhibin; Cheng, Zhenxiang; Jia, Tingting; Kimura, Hideo; Fu, Qiuming; Tao, Hong; Xiong, Liwei

    2018-02-01

    A method to synthesize molybdenum carbides has been developed based on microwave plasma treatment with methane and hydrogen mixed gases, using a microwave-plasma chemical vapor deposition device. The device framework and its mechanism are described in detail. Two-dimensional α-Mo2C has been directly synthesized by a plate-to-plate substrate holder structure with a microwave power of 920 W and a partial pressure of 20 kPa. In-situ optical emission spectroscopy was used to measure the radical types in the plasma ball during glow discharge. The as-grown α-Mo2C samples were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy to determine their phases, purity and chemical groups. The superconducting transition temperature was measured, and the transition temperatures of the relevant phases are discussed in detail. The results confirmed that this method is an efficient way to obtain molybdenum carbides and inspire new research interest in transition metal carbides, which have many intrinsic local properties and applications.

  4. Structural studies of type N superconductive compounds: R2-xCexCuO4±δ (R = Gd, Eu, Sm, Nd, Pr); influences of chemical treatments on physical properties

    International Nuclear Information System (INIS)

    Vigoureux, P.

    1995-06-01

    Different chemical treatments of R 2-x Ce x CuO 4±δ compounds monocrystals (gadolinium, europium, samarium, neodymium and praseodymium cuprates) modify their physical properties especially their superconductive properties. The presented chemical treatments are: the substitution of the trivalent rare earth element R by an other trivalent lanthanide, its substitution by tetravalent cerium, and heat treatment under low oxygen pressure. After these chemical treatments, structural modifications are observed by neutrons and X-rays diffraction, and allow to precise their actions: size effect of the rare earth element on the deformation of the CuO 2 planes, links between deformation and superconductivity and magnetic properties. (A.B.)

  5. Superconducting lead particles produced by chemical techniques

    Science.gov (United States)

    Fariss, T. L.; Nixon, W. E.; Bucelot, T. J.; Deaver, B. S., Jr.; Mitchell, J. W.

    1982-09-01

    The superconductivity of extremely small lead particles has been studied as a function of size, surface condition, and connectivity using chemical techniques to produce particles of well-controlled size and shape suspended in insulating media. Approximately monodisperse suspensions of equiaxed, rod, and lath-shaped particles of lead halides and other lead compounds suspended in gelatin, polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol, methyl cellulose, and hydroxyethyl cellulose have been produced. These particles have been reduced to pseudomorphs of lead in the liquid phase or the suspensions have been coated on substrates and dried before reduction. Reducing solutions containing aminoiminomethanesulfinic acid are effective with particles of lead halides, lead phosphate, lead sulfate, and lead tartrate. Suspensions of smaller discrete lead particles have also been produced by direct reduction of solutions of soluble lead salts containing suitable polymers, chelating, and stabilizing agents. Dispersions with mean particle dimensions between 3 nm and 5 μm, and a narrow size-frequency distribution, have been produced. The superconductivity of the particles has been characterized by measurements of the magnetization as a function of temperature and magnetic field. The larger particles have a transition temperature of 7.2 K, the same as bulk lead; however, for particles of characteristic dimensions less than 20 nm, the transition temperature is lower by ˜0.1 K.

  6. Superconducting lead particles produced by chemical techniques

    International Nuclear Information System (INIS)

    Fariss, T.L.; Nixon, W.E.; Bucelot, T.J.; Deaver, B.S. Jr.; Mitchell, J.W.

    1982-01-01

    The superconductivity of extremely small lead particles has been studied as a function of size, surface condition, and connectivity using chemical techniques to produce particles of well-controlled size and shape suspended in insulating media. Approximately monodisperse suspensions of equiaxed, rod, and lath-shaped particles of lead halides and other lead compounds suspended in gelatin, polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol, methyl cellulose, and hydroxyethyl cellulose have been produced. These particles have been reduced to pseudomorphs of lead in the liquid phase or the suspensions have been coated on substrates and dried before reduction. Reducing solutions containing aminoiminomethanesulfinic acid are effective with particles of lead halides, lead phosphate, lead sulfate, and lead tartrate. Suspensions of smaller discrete lead particles have also been produced by direct reduction of solutions of soluble lead salts containing suitable polymers, chelating, and stabilizing agents. Dispersions with mean particle dimensions between 3 nm and 5 μm, and a narrow size-frequency distribution, have been produced. The superconductivity of the particles has been characterized by measurements of the magnetization as a function of temperature and magnetic field. The larger particles have a transition temperature of 7.2 K, the same as bulk lead; however, for particles of characteristic dimensions less than 20 nm, the transition temperature is lower by approx.0.1 K

  7. Multiple superconducting phases in heavy fermion compounds ...

    Indian Academy of Sciences (India)

    Here we show that multiple superconducting phases are present in heavy fermion superconductors, CeCoIn5 [2] and PrOs4Sb12 [3] , both of which were discovered very recently. The superconducting gap function of PrOs4Sb12 was investigated using thermal transport measurements in magnetic field rotated relative to the.

  8. Multiple superconducting phases in heavy fermion compounds ...

    Indian Academy of Sciences (India)

    ... that in CeCoIn5 the Fulde-Ferrel-Larkin-Ovchinikov (FFLO) phase, in which the order parameter is spatially modulated and has planar nodes aligned perpendicular to the vortices, appears at low temperature and high field. These results open up a new realm for the study of the superconductivity with multiple phases.

  9. Superconducting transition temperature and the formation of closed electron shells in the atoms of superconducting compounds

    International Nuclear Information System (INIS)

    Chapnik, I.M.

    1985-01-01

    The relationship between the regularities in the tansition temperature (T/sub c/) values in analogous compounds (having the same structure and stoichiometry) and the formation of the closed electron shells outside inert gas shells in the atoms of the variable component of the 158 intermetallic superconducting compounds has been discussed. The T/sub c/ data for compounds of the elements from the first long period of the Periodic Table (K to Se) are compared with the T/sub c/ data for the analogous compounds of the elements from the second long period (Rb to Te)

  10. Study of superconducting Ba-Ge-Co compounds

    Science.gov (United States)

    Li, Yang; Ross, J. H.; Larrea, J. A.; Baggio-Saitovitch, Elisa

    2004-08-01

    We prepared samples with starting composition Ba 8-Ge 46- x-Co x ( x=0, 4 and 6) by direct melting. These Ge-based compounds were characterized by X-ray diffraction and WDS, and we found two superconducting transitions at TC=10 and 4 K in the Co-free sample. Co-doping results in the suppression of TC to 7 K. The superconducting volume fraction also decreases with increasing Co-doping. For Co-doped samples, there is no 4 K superconducting transition. X-ray refinement shows that the compounds are mixtures of several phases. The dominant phase is diamond Ge, and we found no Ge-clathrate phases. Besides diamond Ge, there are also several weak diffractions from an unknown Ba-Ge phase, and most of them were indexed on the basis of a monoclinic unit cell. Diffraction peaks for Ba 2Ge, BaGe, BaGe 2, BaGe 2O 5, BaGeO 3, Ba 3GeO 5, α-BaGeO 3, BaGe 2O 5, Ba 2Ge 5O 12, β-BaGeO 3, Ba 2GeO 4 and BaGe 4O 9 were carefully searched for but not seen in the samples. For the Co-doped sample, besides the main diamond Ge phase, there is also a semiconducting phase CoGe 2. With increasing Co content, the CoGe 2 content increases. The WDS results agree with this result. The main phase composition for the Co-free sample is Ba 0.01Ge 99.9. We also discuss the origin of two superconducting transitions in Ge-based compounds.

  11. Magnetic and superconducting order in some random pseudobinary compounds

    International Nuclear Information System (INIS)

    Dongen, J.C.M. van.

    1982-01-01

    This thesis presents the results of a study on the magnetic and superconducting ordering phenomena in some random pseudobinary compounds. In the investigations ternary systems are utilised in which two of the elements form a binary intermetallic compound, e.g. PdH, GdCu and YCo 2 . A third element is then randomly substituted into one of the sublattices without changing the basic intermetallic compound structure. In chapter II a study is presented on the Kondo effect and spin-glass freezing of the magnetic impurities Cr, Mn, and Fe in superconducting palladium hydride. Chapter III contains a study on crystal structure transformations and magnetic ordering phenomena in GdCusub(1-x)Gasub(x) and related pseudobinary compounds. In Chapter IV experiments on the magnetic properties and the electrical resistivity of the transition metal Laves phase compounds Y(Cosub(1-x)Fesub(x)) 2 , Y(Irsub(1-x)Fesub(x)) 2 and Hf(Cosub(1-x)Fesub(x)) 2 are described. (Auth.)

  12. Pluto's Nonvolatile Chemical Compounds

    Science.gov (United States)

    Grundy, William M.; Binzel, Richard; Cook, Jason C.; Cruikshank, Dale P.; Dalle Ore, Cristina M.; Earle, Alissa M.; Ennico, Kimberly; Jennings, Donald; Howett, Carly; Kaiser, Ralf-Ingo; Linscott, Ivan; Lunsford, A. W.; Olkin, Catherine B.; Parker, Alex Harrison; Parker, Joel Wm.; Philippe, Sylvain; Protopapa, Silvia; Quirico, Eric; Reuter, D. C.; Schmitt, Bernard; Singer, Kelsi N.; Spencer, John R.; Stansberry, John A.; Stern, S. Alan; Tsang, Constantine; Verbiscer, Anne J.; Weaver, Harold A.; Weigle, G. E.; Young, Leslie

    2016-10-01

    Despite the migration of Pluto's volatile ices (N2, CO, and CH4) around the surface on seasonal timescales, the planet's non-volatile materials are not completely hidden from view. They occur in a variety of provinces formed over a wide range of timescales, including rugged mountains and chasms, the floors of mid-latitude craters, and an equatorial belt of especially dark and reddish material typified by the informally named Cthulhu Regio. NASA's New Horizons probe observed several of these regions at spatial resolutions as fine as 3 km/pixel with its LEISA imaging spectrometer, covering wavelengths from 1.25 to 2.5 microns. Various compounds that are much lighter than the tholin-like macromolecules responsible for the reddish coloration, but that are not volatile at Pluto surface temperatures such as methanol (CH3OH) and ethane (C2H6) have characteristic absorption bands within LEISA's wavelength range. This presentation will describe their geographic distributions and attempt to constrain their origins. Possibilities include an inheritance from Pluto's primordial composition (the likely source of H2O ice seen on Pluto's surface) or ongoing production from volatile precursors through photochemistry in Pluto's atmosphere or through radiolysis on Pluto's surface. New laboratory data inform the analysis.This work was supported by NASA's New Horizons project.

  13. Magnetism, superconductivity and Fermi surfaces of plutonium compounds

    International Nuclear Information System (INIS)

    Haga, Y.; Aoki, D.; Yamagami, H.; Matsuda, T.D.; Nakajima, K.; Arai, Y.; Homma, Y.; Shiokawa, Y.; Yamamoto, E.; Nakamura, A.; Onuki, Y.

    2007-01-01

    Single crystals of plutonium compounds PuRhGa 5 and PuIn 3 are successfully grown. For PuRhGa 5 , anisotropy of the superconducting upper critical field was found and analyzed by the anisotropic mass model, consistent with quasi-two-dimensional electronic states predicted by band calculations. On the other hand, the de Haas-van Alphen oscillation was observed in PuIn 3 . By comparing with the band calculations, it is concluded that 5f electrons are itinerant in PuIn 3

  14. Thermal expansion of superconducting fulleride and borocarbide compounds

    International Nuclear Information System (INIS)

    Burkhart, G.J.

    1995-08-01

    In order to detact and analyze thermodynamic phase transitions, the investigation of the thermal expansion via capacitance dilatometry is a powerful experimental technique, due to the extremely high resolution (ΔL/L∝10 -8 -10 -10 ). With respect to the air sensitivity of the fullerides a dilatometer operating under inert atmosphere was designed and the thermal expansion of polycrystalline fulleride (Rb 3 C 60 , K 3 C 60 ) and borocarbide (YNi 2 B 2 C, LuNi 2 B 2 C) compounds was determined in the temperature range 5-320 K. Most effort was focused on a quantitative evaluation of the discontinuity in the thermal expansivity α at the superconducting transition. The results are discussed in the context of the Ehrenfest relation, which connects the jump in the thermal expansivity Δα with the pressure dependence of the superconducting transition temperature dT c /dp and the jump in the specific heat Δc p /T c at the superconducting transition. For Rb 3 C 60 and K 3 C 60 the jump in the specific heat can be derived via the Ehrenfest relation using the results of the thermal expansion measurements and the well-known pressure dependence of the superconducting transition temperature. The derived values for Rb 3 C 60 and K 3 Cu 60 are Δc p /T c ∝75mJ/molK 2 and Δc p /T c ∝64 mJ.molK 2 , respectively. The directly measured specific heat jump of K 3 C 60 gives approximately the same value of Δc p /T c , and, therefore, the use of the Ehrenfest relation on fullerides is justified. The specific heat jumps Δc p /T c , determined from theoretically derived values of the density of states at the Fermi level N(E F ) and the McMillan-parameter λ, exceed the experimental results by a factor of 1.5-2. This finding reflects the uncertainty concerning the superconducting parameters N(E F ) and λ. (orig.)

  15. Pressure induced Superconductivity in the Charge Density Wave Compound Tritelluride

    Energy Technology Data Exchange (ETDEWEB)

    Hamlin, J.J.; Zocco, D.A.; Sayles, T.A.; Maple, M.B.; /UC, Davis; Chu, J.-H.; Fisher, I.R.; /Stanford U., Geballe Lab.

    2010-02-15

    A series of high-pressure electrical resistivity measurements on single crystals of TbTe{sub 3} reveal a complex phase diagram involving the interplay of superconducting, antiferromagnetic and charge density wave order. The onset of superconductivity reaches a maximum of almost 4 K (onset) near {approx} 12.4 GPa.

  16. Competition between magnetism and superconductivity in Eu-based intermetallic compounds

    Science.gov (United States)

    Stavinoha, Macy; Green, Lance; Chan, Julia; Morosan, Emilia

    Eu-based intermetallic compounds present a path to discover new correlated electronic behavior in quantum materials. Reports of superconductivity, intermediate valence behavior, and heavy fermions indicate that Eu-based compounds are promising routes to study the relationship between crystallography and electronic properties. The present work is focused on EuGa4, an antiferromagnet with TN = 16 K isostructural with the tetragonal RT2M2 (R = rare earth, T = transition metal, M = metal or metalloid) family that exhibits heavy fermion behavior and unconventional superconductivity. Single crystals of the doped series (Eu1-xLax)Ga4, (Eu1-xCax)Ga4, and Eu(Ga1-xAlx)4 have been grown using the self-flux method and tested for change in unit cell volume and magnetic susceptibility. Results show that doping with Ca (isoelectronic doping) and La (hole doping) reduce TN to 12.4 K and 2.3 K, respectively, for Ca doping up to x = 0.11 and La doping up to x = 0.74 without an associated change in unit cell volume. The series Eu(Ga1-xAlx)4 has shown incommensurate-to-commensurate magnetic transitions. Future studies will aim to further decrease TN and the unit cell volume using physical pressure and chemical pressure through doping. ICAM, Gordon and Betty Moore Foundation.

  17. Structural studies of type N superconductive compounds: R{sub 2-x}Ce{sub x}CuO{sub 4{+-}{delta}} (R = Gd, Eu, Sm, Nd, Pr); influences of chemical treatments on physical properties; Etudes structurales des composes supraconducteurs de type N: R{sub 2-x}Ce{sub x}CuO{sub 4{+-}{delta}} (R = Gd, Eu, Sm, Nd, Pr); influences des traitements chimiques sur les proprietes physiques

    Energy Technology Data Exchange (ETDEWEB)

    Vigoureux, P.

    1995-06-01

    Different chemical treatments of R{sub 2-x}Ce{sub x}CuO{sub 4{+-}{delta}} compounds monocrystals (gadolinium, europium, samarium, neodymium and praseodymium cuprates) modify their physical properties especially their superconductive properties. The presented chemical treatments are: the substitution of the trivalent rare earth element R by an other trivalent lanthanide, its substitution by tetravalent cerium, and heat treatment under low oxygen pressure. After these chemical treatments, structural modifications are observed by neutrons and X-rays diffraction, and allow to precise their actions: size effect of the rare earth element on the deformation of the CuO{sub 2} planes, links between deformation and superconductivity and magnetic properties. (A.B.). 394 refs/.

  18. Superconductivity

    CERN Document Server

    Poole, Charles P; Farach, Horacio A

    1995-01-01

    Superconductivity covers the nature of the phenomenon of superconductivity. The book discusses the fundamental principles of superconductivity; the essential features of the superconducting state-the phenomena of zero resistance and perfect diamagnetism; and the properties of the various classes of superconductors, including the organics, the buckministerfullerenes, and the precursors to the cuprates. The text also describes superconductivity from the viewpoint of thermodynamics and provides expressions for the free energy; the Ginzburg-Landau and BCS theories; and the structures of the high

  19. Superconductivity

    International Nuclear Information System (INIS)

    2007-01-01

    During 2007, a large amount of the work was centred on the ITER project and related tasks. The activities based on low-temperature superconducting (LTS) materials included the manufacture and qualification of ITER full-size conductors under relevant operating conditions, the design of conductors and magnets for the JT-60SA tokamak and the manufacture of the conductors for the European dipole facility. A preliminary study was also performed to develop a new test facility at ENEA in order to test long-length ITER or DEMO full-size conductors. Several studies on different superconducting materials were also started to create a more complete database of superconductor properties, and also for use in magnet design. In this context, an extensive measurement campaign on transport and magnetic properties was carried out on commercially available NbTi strands. Work was started on characterising MgB 2 wire and bulk samples to optimise their performance. In addition, an intense experimental study was started to clarify the effect of mechanical loads on the transport properties of multi-filamentary Nb 3 Sn strands with twisted or untwisted superconducting filaments. The experimental activity on high-temperature superconducting (HTS) materials was mainly focussed on the development and characterisation of YBa 2 Cu 3 O 7-X (YBCO) based coated conductors. Several characteristics regarding YBCO deposition, current transport performance and tape manufacture were investigated. In the framework of chemical approaches for YBCO film growth, a new method, developed in collaboration with the Technical University of Cluj-Napoca (TUCN), Romania, was studied to obtain YBCO film via chemical solution deposition, which modifies the well-assessed metallic organic deposition trifluoroacetate (MOD-TFA) approach. The results are promising in terms of critical current and film thickness values. YBCO properties in films with artificially added pinning sites were characterised in collaboration with

  20. Automated compound classification using a chemical ontology

    Directory of Open Access Journals (Sweden)

    Bobach Claudia

    2012-12-01

    Full Text Available Abstract Background Classification of chemical compounds into compound classes by using structure derived descriptors is a well-established method to aid the evaluation and abstraction of compound properties in chemical compound databases. MeSH and recently ChEBI are examples of chemical ontologies that provide a hierarchical classification of compounds into general compound classes of biological interest based on their structural as well as property or use features. In these ontologies, compounds have been assigned manually to their respective classes. However, with the ever increasing possibilities to extract new compounds from text documents using name-to-structure tools and considering the large number of compounds deposited in databases, automated and comprehensive chemical classification methods are needed to avoid the error prone and time consuming manual classification of compounds. Results In the present work we implement principles and methods to construct a chemical ontology of classes that shall support the automated, high-quality compound classification in chemical databases or text documents. While SMARTS expressions have already been used to define chemical structure class concepts, in the present work we have extended the expressive power of such class definitions by expanding their structure-based reasoning logic. Thus, to achieve the required precision and granularity of chemical class definitions, sets of SMARTS class definitions are connected by OR and NOT logical operators. In addition, AND logic has been implemented to allow the concomitant use of flexible atom lists and stereochemistry definitions. The resulting chemical ontology is a multi-hierarchical taxonomy of concept nodes connected by directed, transitive relationships. Conclusions A proposal for a rule based definition of chemical classes has been made that allows to define chemical compound classes more precisely than before. The proposed structure-based reasoning

  1. Automated compound classification using a chemical ontology.

    Science.gov (United States)

    Bobach, Claudia; Böhme, Timo; Laube, Ulf; Püschel, Anett; Weber, Lutz

    2012-12-29

    Classification of chemical compounds into compound classes by using structure derived descriptors is a well-established method to aid the evaluation and abstraction of compound properties in chemical compound databases. MeSH and recently ChEBI are examples of chemical ontologies that provide a hierarchical classification of compounds into general compound classes of biological interest based on their structural as well as property or use features. In these ontologies, compounds have been assigned manually to their respective classes. However, with the ever increasing possibilities to extract new compounds from text documents using name-to-structure tools and considering the large number of compounds deposited in databases, automated and comprehensive chemical classification methods are needed to avoid the error prone and time consuming manual classification of compounds. In the present work we implement principles and methods to construct a chemical ontology of classes that shall support the automated, high-quality compound classification in chemical databases or text documents. While SMARTS expressions have already been used to define chemical structure class concepts, in the present work we have extended the expressive power of such class definitions by expanding their structure-based reasoning logic. Thus, to achieve the required precision and granularity of chemical class definitions, sets of SMARTS class definitions are connected by OR and NOT logical operators. In addition, AND logic has been implemented to allow the concomitant use of flexible atom lists and stereochemistry definitions. The resulting chemical ontology is a multi-hierarchical taxonomy of concept nodes connected by directed, transitive relationships. A proposal for a rule based definition of chemical classes has been made that allows to define chemical compound classes more precisely than before. The proposed structure-based reasoning logic allows to translate chemistry expert knowledge into a

  2. Superconductivity

    International Nuclear Information System (INIS)

    Andersen, N.H.; Mortensen, K.

    1988-12-01

    This report contains lecture notes of the basic lectures presented at the 1st Topsoee Summer School on Superconductivity held at Risoe National Laboratory, June 20-24, 1988. The following lecture notes are included: L.M. Falicov: 'Superconductivity: Phenomenology', A. Bohr and O. Ulfbeck: 'Quantal structure of superconductivity. Gauge angle', G. Aeppli: 'Muons, neutrons and superconductivity', N.F. Pedersen: 'The Josephson junction', C. Michel: 'Physicochemistry of high-T c superconductors', C. Laverick and J.K. Hulm: 'Manufacturing and application of superconducting wires', J. Clarke: 'SQUID concepts and systems'. (orig.) With 10 tabs., 128 figs., 219 refs

  3. Superconducting properties and the structural transition in compounds with the A-15 lattice

    Energy Technology Data Exchange (ETDEWEB)

    Gor' kov, L.P.; Dorokhov, O.N.

    1976-11-01

    The dependence of T/sub c/ on composition and strain is computed and compared with the corresponding dependence of T/sub m/. It is shown that the superconducting and structural properties of the A-15 compounds can be described, at least qualitatively, in the quasi-one-dimensional model previously developed by the authors. It is assumed that the superconductivity mechanism is analogous to that of the BCS theory. The upper critical field, H/sub c//sub 2/, of the V/sub 3/Si and Nb/sub 3/Sn compounds turns out to be much higher than that of V or Nb.

  4. Competition between phonon superconductivity and Kondo screening in mixed valence and heavy fermion compounds

    Science.gov (United States)

    Barzykin, Victor; Gor'Kov, L. P.

    2005-06-01

    We consider competition of the Kondo effect and s -wave superconductivity in heavy fermion and mixed valence superconductors, using the phenomenological approach for the periodic Anderson model. Similar to the well known results for the single-impurity Kondo effect in superconductors, we have found the principal possibility of a reentrant regime of the superconducting transition temperature, Tc , in heavy fermion superconductors in a narrow range of model parameters and concentration of f electrons. Suppression of Tc in mixed valence superconductors is much weaker. Our theory has the most validity in the low-temperature Fermi liquid regime, without reentrant behavior of Tc . To check its applicability, we performed the fit for the x dependence of Tc in Ce1-xLaxRu3Si2 and obtained an excellent agreement with the experimental data, although no reentrance was found in this case. Other experimental data are discussed in the light of our theoretical analysis. In particular, we compare temperatures of the superconducting transition for some known homologs, i.e., the analog periodic lattice compounds with and without f elements. For a few pairs of homologs, superconductivity exists only in the heavy fermion materials, thus confirming the uniqueness of superconductivity mechanisms for the latter. We suggest that for some other compounds, the value of Tc may remain of the same order in the two homologs, if superconductivity originates mainly on some light Fermi surface, but induces a sizable superconducting gap on another Fermi surface, for which hybridization or other heavy fermion effects are more significant. By passing, we cite the old results that show that the jump in the specific heat at the transition reflects the heaviness of carriers on this Fermi surface independently of mechanisms responsible for superconductivity.

  5. Quantum chemical studies of estrogenic compounds

    Science.gov (United States)

    Quantum chemical methods are potent tools to provide information on the chemical structure and electronic properties of organic molecules. Modern computational chemistry methods have provided a great deal of insight into the binding of estrogenic compounds to estrogenic receptors (ER), an important ...

  6. Superconductivity and magnetic order in the noncentrosymmetric half-Heusler compound ErPdBi

    NARCIS (Netherlands)

    Pan, Y.; Nikitin, A.M.; Bay, T.V.; Huang, Y.K.; Paulsen, C.; Yan, B.H.; de Visser, A.

    2013-01-01

    We report superconductivity at Tc = 1.22 K and magnetic order at TN = 1.06\\ K in the semimetallic noncentrosymmetric half-Heusler compound ErPdBi. The upper critical field, Bc2, has an unusual quasi-linear temperature variation and reaches a value of 1.6 T for T - 0 . Magnetic order is found below

  7. Superconductivity

    CERN Document Server

    Ketterson, John B

    2008-01-01

    Conceived as the definitive reference in a classic and important field of modern physics, this extensive and comprehensive handbook systematically reviews the basic physics, theory and recent advances in the field of superconductivity. Leading researchers, including Nobel laureates, describe the state-of-the-art in conventional and unconventional superconductors at a particularly opportune time, as new experimental techniques and field-theoretical methods have emerged. In addition to full-coverage of novel materials and underlying mechanisms, the handbook reflects continued intense research into electron-phone based superconductivity. Considerable attention is devoted to high-Tc superconductivity, novel superconductivity, including triplet pairing in the ruthenates, novel superconductors, such as heavy-Fermion metals and organic materials, and also granular superconductors. What’s more, several contributions address superconductors with impurities and nanostructured superconductors. Important new results on...

  8. Organometallic compounds: an opportunity for chemical biology?

    Science.gov (United States)

    Patra, Malay; Gasser, Gilles

    2012-06-18

    Organometallic compounds are renowned for their remarkable applications in the field of catalysis, but much less is known about their potential in chemical biology. Indeed, such compounds have long been considered to be either unstable under physiological conditions or cytotoxic. As a consequence, little attention has been paid to their possible utilisation for biological purposes. Because of their outstanding physicochemical properties, which include chemical stability, structural diversity and unique photo- and electrochemical properties, however, organometallic compounds have the ability to play a leading role in the field of chemical biology. Indeed, remarkable examples of the use of such compounds-notably as enzyme inhibitors and as luminescent agents-have recently been reported. Here we summarise recent advances in the use of organometallic compounds for chemical biology purposes, an area that we define as "organometallic chemical biology". We also demonstrate that these recent discoveries are only a beginning and that many other organometallic complexes are likely to be found useful in this field of research in the near future. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. High temperature superconducting compounds II; Proceedings of the Second Symposium, Anaheim, CA, Feb. 20, 21, 1990

    International Nuclear Information System (INIS)

    Whang, S.H.; Dasgupta, A.; Laibowitz, R.

    1990-01-01

    Various topics relevant to the production and implementation of high-temperature superconducting compounds are highlighted including critical current; texturing; ceramics and novel processing; composites; deformation and consolidation; thin films; microstructures; tapes, filaments, and ribbons; and thermodynamics. The thermally activated flux creep, critical current density and current enhancement in high-temperature superconductors are addressed. Also discussed are the phase stability and microstructure of doped superconductors, mechanical considerations in the processing of high-Tc superconductors, fabrication and application of high current density, high RTc superconducting thin films and devices, the effect of substrate temperature and RF biasing on the composition of sputtered Bi-based superconducting thin films, and optical electron microanalysis of cuprate superconductors. The microstructure dependence of critical current density and fabrication of double-layered ribbons from cuprate are also discussed

  10. Superconductivity in pressurized CeRhG e3 and related noncentrosymmetric compounds

    Science.gov (United States)

    Wang, Honghong; Guo, Jing; Bauer, Eric D.; Sidorov, Vladimir A.; Zhao, Hengcan; Zhang, Jiahao; Zhou, Yazhou; Wang, Zhe; Cai, Shu; Yang, Ke; Li, Aiguo; Li, Xiaodong; Li, Yanchun; Sun, Peijie; Yang, Yi-feng; Wu, Qi; Xiang, Tao; Thompson, J. D.; Sun, Liling

    2018-02-01

    We report the discovery of superconductivity in pressurized CeRhG e3 , a nonsuperconducting member of the isostructural family of noncentrosymmetric heavy-fermion compounds Ce T X3 (T =Co , Rh, Ir and X =Si , Ge). Superconductivity appears in CeRhG e3 at a pressure of 19.6 GPa and the transition temperature TC reaches a maximum value of 1.3 K at 21.5 GPa. This finding provides an opportunity to establish systematic correlations between superconductivity and material properties within this family. Though ambient-pressure unit-cell volumes and critical pressures for superconductivity vary substantially across the series, all family members reach a maximum TCmax at a common (±1.7%) critical cell volume Vcrit, and TCmax at Vcrit increases with increasing spin-orbit coupling strength of the d electrons. These correlations show that substantial Kondo and spin-orbit couplings favor superconductivity in this family, the latter reflecting the role of broken centrosymmetry.

  11. Superconductivity

    CERN Document Server

    Poole, Charles P; Creswick, Richard J; Prozorov, Ruslan

    2014-01-01

    Superconductivity, Third Edition is an encyclopedic treatment of all aspects of the subject, from classic materials to fullerenes. Emphasis is on balanced coverage, with a comprehensive reference list and significant graphics from all areas of the published literature. Widely used theoretical approaches are explained in detail. Topics of special interest include high temperature superconductors, spectroscopy, critical states, transport properties, and tunneling. This book covers the whole field of superconductivity from both the theoretical and the experimental point of view. This third edition features extensive revisions throughout, and new chapters on second critical field and iron based superconductors.

  12. μSR and NMR study of the superconducting Heusler compound YPd2Sn

    Science.gov (United States)

    Saadaoui, H.; Shiroka, T.; Amato, A.; Baines, C.; Luetkens, H.; Pomjakushina, E.; Pomjakushin, V.; Mesot, J.; Pikulski, M.; Morenzoni, E.

    2013-09-01

    We report on muon-spin rotation and relaxation (μSR) and 119Sn nuclear magnetic resonance (NMR) measurements to study the microscopic superconducting and magnetic properties of the Heusler compound with the highest superconducting transition temperature, YPd2Sn (Tc=5.4 K). Measurements in the vortex state provide the temperature dependence of the effective magnetic penetration depth λ(T) and the field dependence of the superconducting gap Δ(0). The results are consistent with a very dirty s-wave BCS superconductor with a gap Δ(0)=0.85(3) meV, λ(0)=212(1) nm, and a Ginzburg-Landau coherence length ξGL(0)≅23 nm. In spite of its very dirty character, the effective density of condensed charge carriers is high compared to that in the normal state. The μSR data in a broad range of applied fields are well reproduced by taking into account a field-related reduction of the effective superconducting gap. Zero-field μSR measurements, sensitive to the possible presence of very small magnetic moments, do not show any indications of magnetism in this compound.

  13. Strain induced superconductivity in the parent compound BaFe2As2

    Science.gov (United States)

    Engelmann, J.; Grinenko, V.; Chekhonin, P.; Skrotzki, W.; Efremov, D. V.; Oswald, S.; Iida, K.; Hühne, R.; Hänisch, J.; Hoffmann, M.; Kurth, F.; Schultz, L.; Holzapfel, B.

    2013-12-01

    The discovery of superconductivity with a transition temperature, Tc, up to 65 K in single-layer FeSe (bulk Tc=8 K) films grown on SrTiO3 substrates has attracted special attention to Fe-based thin films. The high Tc is a consequence of the combined effect of electron transfer from the oxygen-vacant substrate to the FeSe thin film and lattice tensile strain. Here we demonstrate the realization of superconductivity in the parent compound BaFe2As2 (no bulk Tc) just by tensile lattice strain without charge doping. We investigate the interplay between strain and superconductivity in epitaxial BaFe2As2 thin films on Fe-buffered MgAl2O4 single crystalline substrates. The strong interfacial bonding between Fe and the FeAs sublattice increases the Fe-Fe distance due to the lattice misfit, which leads to a suppression of the antiferromagnetic spin density wave and induces superconductivity with bulk Tc≈10 K. These results highlight the role of structural changes in controlling the phase diagram of Fe-based superconductors.

  14. Chemical effect on diffusion in intermetallic compounds

    Science.gov (United States)

    Chen, Yi-Ting

    With the trend of big data and the Internet of things, we live in a world full of personal electronic devices and small electronic devices. In order to make the devices more powerful, advanced electronic packaging such as wafer level packaging or 3D IC packaging play an important role. Furthermore, ?-bumps, which connect silicon dies together with dimension less than 10 ?m, are crucial parts in advanced packaging. Owing to the dimension of ?-bumps, they transform into intermetallic compound from tin based solder after the liquid state bonding process. Moreover, many new reliability issues will occur in electronic packaging when the bonding materials change; in this case, we no longer have tin based solder joint, instead, we have intermetallic compound ?-bumps. Most of the potential reliability issues in intermetallic compounds are caused by the chemical reactions driven by atomic diffusion in the material; thus, to know the diffusivities of atoms inside a material is significant and can help us to further analyze the reliability issues. However, we are lacking these kinds of data in intermetallic compound because there are some problems if used traditional Darken's analysis. Therefore, we considered Wagner diffusivity in our system to solve the problems and applied the concept of chemical effect on diffusion by taking the advantage that large amount of energy will release when compounds formed. Moreover, by inventing the holes markers made by Focus ion beam (FIB), we can conduct the diffusion experiment and obtain the tracer diffusivities of atoms inside the intermetallic compound. We applied the technique on Ni3Sn4 and Cu3Sn, which are two of the most common materials in electronic packaging, and the tracer diffusivities are measured under several different temperatures; moreover, microstructure of the intermetallic compounds are investigated to ensure the diffusion environment. Additionally, the detail diffusion mechanism was also discussed in aspect of diffusion

  15. Unconventional superconductivity of the heavy fermion compound UNi{sub 2}Al{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Zakharov, Andrey

    2008-07-01

    The heavy fermion compound UNi{sub 2}Al{sub 3} exhibits the coexistence of superconductivity and magnetic order at low temperatures, stimulating speculations about possible exotic Cooper-pairing interaction in this superconductor. However, the preparation of good quality bulk single crystals of UNi{sub 2}Al{sub 3} has proven to be a non-trivial task due to metallurgical problems, which result in the formation of an UAl{sub 2} impurity phase and hence a strongly reduced sample purity. The present work concentrates on the preparation, characterization and electronic properties investigation of UNi{sub 2}Al{sub 3} single crystalline thin film samples. The preparation of thin films was accomplished in a molecular beam epitaxy (MBE) system. (100)-oriented epitaxial thin films of UNi{sub 2}Al{sub 3} were grown on single crystalline YAlO{sub 3} substrates cut in (010)- or (112)-direction. The high crystallographic quality of the samples was proved by several characterisation methods, such as X-ray analysis, RHEED and TEM. To study the magnetic structure of epitaxial thin films resonant magnetic X-ray scattering was employed. The magnetic order of thin the film samples, the formation of magnetic domains with different moment directions, and the magnetic correlation length were discussed. The electronic properties of the UNi{sub 2}Al{sub 3} thin films in the normal and superconducting states were investigated by means of transport measurements. A pronounced anisotropy of the temperature dependent resistivity {rho}(T) was observed. Moreover, it was found that the temperature of the resistive superconducting transition depends on the current direction, providing evidence for multiband superconductivity in UNi{sub 2}Al{sub 3}. The initial slope of the upper critical field H'{sub c2}(T) of the thin film samples suggests an unconventional spin-singlet superconducting state, as opposed to bulk single crystal data. To probe the superconducting gap of UNi{sub 2}Al{sub 3

  16. Discovery of a Superconducting Cu-Bi Intermetallic Compound by High-Pressure Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Samantha M. [Department of Chemistry, Northwestern University, Evanston IL 60208 USA; Walsh, James P. S. [Department of Chemistry, Northwestern University, Evanston IL 60208 USA; Amsler, Maximilian [Department of Materials Science and Engineering, Northwestern University, Evanston IL 60208 USA; Malliakas, Christos D. [Department of Chemistry, Northwestern University, Evanston IL 60208 USA; Yu, Tony [Center for Advanced Radiation Sources, The University of Chicago, Chicago IL 60637 USA; Goedecker, Stefan [Department of Physics, Universität Basel, Kingelbergstr. 82 4056 Basel Switzerland; Wang, Yanbin [Center for Advanced Radiation Sources, The University of Chicago, Chicago IL 60637 USA; Wolverton, Chris [Department of Materials Science and Engineering, Northwestern University, Evanston IL 60208 USA; Freedman, Danna E. [Department of Chemistry, Northwestern University, Evanston IL 60208 USA

    2016-09-26

    A new intermetallic compound, the first to be structurally identified in the Cu-Bi binary system, is reported. This compound is accessed by high-pressure reaction of the elements. Its detailed characterization, physical property measurements, and ab initio calculations are described. The commensurate crystal structure of Cu11Bi7 is a unique variation of the NiAs structure type. Temperature-dependent electrical resistivity and heat capacity measurements reveal a bulk superconducting transition at Tc=1.36 K. Density functional theory calculations further demonstrate that Cu11Bi7 can be stabilized (relative to decomposition into the elements) at high pressure and temperature. These results highlight the ability of high-pressure syntheses to allow for inroads into heretofore-undiscovered intermetallic systems for which no thermodynamically stable binaries are known.

  17. Discovery of a superconducting Cu-Bi intermetallic compound by high-pressure synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, Samantha M.; Walsh, James P.S.; Malliakas, Christos D.; Freedman, Danna E. [Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Amsler, Maximilian; Wolverton, Chris [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering; Yu, Tony; Wang, Yanbin [Chicago Univ., IL (United States). Center for Advanced Radiation Sources; Goedecker, Stefan [Basel Univ. (Switzerland). Dept. of Physics

    2016-10-17

    A new intermetallic compound, the first to be structurally identified in the Cu-Bi binary system, is reported. This compound is accessed by high-pressure reaction of the elements. Its detailed characterization, physical property measurements, and ab initio calculations are described. The commensurate crystal structure of Cu{sub 11}Bi{sub 7} is a unique variation of the NiAs structure type. Temperature-dependent electrical resistivity and heat capacity measurements reveal a bulk superconducting transition at T{sub c}=1.36 K. Density functional theory calculations further demonstrate that Cu{sub 11}Bi{sub 7} can be stabilized (relative to decomposition into the elements) at high pressure and temperature. These results highlight the ability of high-pressure syntheses to allow for inroads into heretofore-undiscovered intermetallic systems for which no thermodynamically stable binaries are known.

  18. Transport measurements on superconducting iron pnictides and Heusler compounds; Transportmessungen an Supraleitenden Eisenpniktiden und Heusler-Verbindungen

    Energy Technology Data Exchange (ETDEWEB)

    Bombor, Dirk

    2014-09-05

    In this work, results of electronic transport measurements are discussed for superconducting iron pnictides as well as for ferromagnetic Heusler compounds. The iron pnictides are a recently discovered class of high temperature superconductors where magnetism might play a crucial role. While the 122-pnictides show antiferromagnetism and migrate to the superconducting state upon doping, ferromagnetism has been observed in doped LiFeAs. On the other hand, in the undoped state this material shows interesting superconducting properties. Among other properties, Heusler compounds are well known due to their ferromagnetism. Co{sub 2}FeSi, which was investigated in this work, is one of the strongest ferromagnets. Beside this, one predicts this compound to be a half-metallic ferromagnet with completely spin polarized electronic transport where all conducting electrons have the same spin. The here addressed properties can well be investigated with the method of electronic transport measurements, whose results on single crystals are discussed in this work.

  19. Solid-state ionics: Studies of lithium-conducting sulfide glasses and a superconducting oxide compound

    International Nuclear Information System (INIS)

    Ahn, Byung Tae.

    1989-01-01

    The first part of this work studies lithium-conducting sulfide glasses for battery applications, while the second part studies the thermodynamic properties of a superconducting oxide compound by using an oxide electrolyte. Lithium conducting glasses based on the SiS 2 -Li 2 S system are possible solid electrolytes for high-energy-density lithium batteries. The foremost requirement for solid electrolytes is that they should have high ionic conductivities. Unfortunately, most crystalline lithium conductors have low ionic conductivities at room temperature. However, glass ionic conductors show higher ionic conductivities than do crystalline forms of the same material. In addition to higher ionic conductivities, glasses appear to have several advantages over crystalline materials. These advantages include isotropic conductivity, absence of grain boundary effects, ease of glass forming, and the potential for a wide range of stability to oxidizing and reducing conditions. Using pyrolitic graphite-coated quartz ampoules, new ternary compounds and glasses in the SiS 2 -Li 2 S system were prepared. Several techniques were used to characterize the materials: powder x-ray diffraction, differential thermal analysis, differential scanning calorimetry, and AC impedance spectroscopy. The measured lithium conductivity of the sulfide glasses was one of the highest among the known solid lithium conductors. Measuring the equilibrium open circuit voltages assisted in determining the electrochemical stabilities of the ternary compounds and glasses with respect to pure Li. A solid-state ionic technique called oxygen coulometric titration was used to measure the thermodynamic stability, the oxygen stoichiometry, and the effects of the oxygen stoichiometry, and the effects of the oxygen stoichiometry and the cooling rate on superconductivity of the YBa 2 Cu 3 O 7-x compound were investigated

  20. Trigermanides AEGe{sub 3} (AE = Ca, Sr, Ba). Chemical bonding and superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, Rodrigo; Schnelle, Walter; Baranov, Alexey I.; Burkhardt, Ulrich; Bobnar, Matej; Cardoso-Gil, Raul; Schwarz, Ulrich; Grin, Yuri [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

    2016-08-01

    The crystal structures of the trigermanides AEGe{sub 3}(tI32) (AE = Ca, Sr, Ba; space group I4/mmm, for SrGe{sub 3}: a = 7.7873(1), c = 12.0622(3) Aa) comprise Ge{sub 2} dumbbells forming layered Ge substructures which enclose embedded AE atoms. The chemical bonding analysis by application of the electron localizability approach reveals a substantial charge transfer from the AE atoms to the germanium substructure. The bonding within the dumbbells is of the covalent two-center type. A detailed analysis of SrGe{sub 3} reveals that the interaction on the bond-opposite side of the Ge{sub 2} groups is not lone pair-like - as it would be expected from the Zintl-like interpretation of the crystal structure with anionic Ge layers separated by alkaline-earth cations - but multi-center strongly polar between the Ge{sub 2} dumbbells and the adjacent metal atoms. Similar atomic interactions are present in CaGe{sub 3} and BaGe{sub 3}. The variation of the alkaline-earth metal has a merely insignificant influence on the superconducting transition temperatures in the s,p-electron compounds AEGe{sub 3}.

  1. New superconducting intercalation compounds of organic five-membered heterocyclic compounds with 2H-tantalum disulfide

    International Nuclear Information System (INIS)

    Hummel, H.U.; Fackler, R.; Remmert, P.

    1992-01-01

    The intercalation compounds TaS 2 (pyrrole) 0.5 (1), TaS 2 (2-methylpyrrole) 0.33 (2), TaS 2 (2,5-dimethylpyrrole) (3), TaS 2 (thiazole) 0.33 (4) and TaS 2 (imidazole) 0.33 (5) are formed readily in closed systems at temperatures up to 200degC. Furane and thiophene show no tendency to intercalate in 2H-TaS 2 . Compounds 2-5 are molecular intercalation species, and deintercalation is finished at 350degC, while in 1 the pyrrole guests have been associated and thermally induced deintercalation proceeds up to 900degC with fragmentation. 1-5 can be indexed on the basis of hexagonal symmetry assuming the space group P6 3 /mmc. In 1 the stacking sequence of the host lattice TaS 2 remains unchanges while in 2, 3 and 5 a transformation from the BaB CaC stacking of 2H-TaS 2 to a sequence AbA AcA occurs. In 4 a stacking CbC BcB like in MoS 2 is realized. 1-5 show superconducting behaviour at low temperatures, 2 exhibits a pronounced metall-semiconductor transition at 220 K. (orig.)

  2. Reclamation of niobium compounds from ionic liquid electrochemical polishing of superconducting radio frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Wixtrom, Alex I. [Christopher Newport University, Newport News, VA (United States); Buhler, Jessica E. [Christopher Newport University, Newport News, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Abdel-Fattah, Tarek M. [Christopher Newport University, Newport News, VA (United States)

    2013-06-01

    Recent research has shown that choline chloride (vitamin B4)-based solutions can be used as a greener alternative to acid-based electrochemical polishing solutions. This study demonstrated a successful method for electrochemical deposition of niobium compounds onto the surface of copper substrates using a novel choline chloride-based ionic liquid. Niobium ions present in the ionic liquid solution were dissolved into the solution prior to deposition via electrochemical polishing of solid niobium. A black coating was clearly visible on the surface of the Cu following deposition. This coating was analyzed using scanning electron microscopy (SEM), electron dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and X-ray fluorescence spectroscopy (XRF). This ionic liquid-based electrochemical deposition method effectively recycles previously dissolved niobium from electrochemical polishing of superconducting radio frequency (SRF) cavities.

  3. Atomic ordering, phase stability and superconductivity in bulk and filamentary A15 type compounds

    International Nuclear Information System (INIS)

    Fluekiger, R.

    1987-05-01

    The influence of atomic ordering effects and ordering kinetics on the superconducting and metallurgical properties of A15 type compounds are critically discussed based on own and literature data. First, the techniques for determining the order parameter are reviewed. The dependence of T c vs. S in various A15 type compounds as a function of the quenching temperature and of the high energy particle irradiation fluence is discussed. A model for the disordering mechanism in A15 compounds is established, based on the new concept of the virtual lattice site. It is shown that the disordering mechanism is the same in both cases, high temperature heat treatment and high energy particle irradiation. The very complete representation of ordering effects also contains the variation of other properties, e.g. γ, θ D , ρ o and B c2 (0). Furthermore, it allows to draw empirical correlations between atomic ordering and A15 phase stability. Finally, it is shown on selected examples that the optimization of the critical current density at high fields in Nb 3 Sn wires by alloying is nothing else than a consequence of the occurrence of perfect atomic ordering in binary Nb 3 Sn. (orig.)

  4. Alteration of the superconducting properties of A15 compounds and elementary composite superconductors by non-hydrostatic elastic strain

    International Nuclear Information System (INIS)

    Welch, D.O.

    1979-01-01

    Elastic strains alter (usually, but not always, adversely) the critical temperatures, magnetic fields, and current densities of superconducting A15 compounds; non-hydrostatic strain states are particularly effective in this regard. This paper is a review of the experimental evidence, obtained by a variety of techniques, concerning the strain dependence of the critical properties of a number of A15 compounds and a discussion of theoretical models for describing such effects

  5. A Review of Metalorganic Chemical Vapor Deposition of High-Temperature Superconducting Thin Films

    Science.gov (United States)

    Erbil, Ahmet; Zhang, K.; Kwak, B. S.; Boyd, E. P.

    1990-03-01

    A status report is given on the metalorganic chemical vapor deposition (MOCVD) of high-temperature superconducting thin films. The advantages of MOCVD processing manifest themselves in the quality of the films produced, and in the economy of the process. Metalorganic precursor requirements, deposition parameters and film properties are discussed. Also difficulties have been identified in making MOCVD a manufacturing technology. To solve these problems, future research directions are proposed.

  6. Chemical shift of UL 3 edges in different uranium compounds ...

    Indian Academy of Sciences (India)

    Energy shifts of ∼ 2–3 eV were observed for U L3 edge in the U-compounds compared to their value in elemental U. The different chemical shifts observed for the compounds having the same oxidation state of the cation but different anions or ligands show the effect of different chemical environments surrounding the ...

  7. Magnetic precursor of the pressure-induced superconductivity in Fe-ladder compound

    Science.gov (United States)

    Chi, Songxue; Uwatoko, Yoshiya; Cao, Huibo; Hirata, Yasuyuki; Hashizume, Kazuki; Aoyama, Takuya; Ohgushi, Kenya

    The pressure effects on the antiferromagentic orders in iron-based ladder compounds CsFe2Se3 and BaFe2S3 have been studied using neutron diffraction. With identical crystal structure and similar magnetic structures, the two compounds exhibit highly contrasting magnetic behaviors under moderate external pressures. In CsFe2Se3 the ladders are brought much closer to each other by pressure, but the stripe-type magnetic order shows no observable change. In contrast, the stripe order in BaFe2S3, undergoes a quantum phase transition where an abrupt increase of N e xel temperature by more than 50% occurs at about 1 GPa, accompanied by a jump in the ordered moment. With its spin structure unchanged, BaFe2S3 enters an enhanced magnetic phase that bears the characteristics of an orbital selective Mott phase, which is the true neighbor of superconductivity emerging at higher pressures. Research at Oak Ridge National Laboratorys HFIR was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.This work was supported by JSPS KAKENHI Grant Number 16H04019.

  8. Fabrication of Chemically Doped, High Upper Critical Field Magnesium Diboride Superconducting Wires

    International Nuclear Information System (INIS)

    Marzik, James V.

    2005-01-01

    Controlled chemical doping of magnesium diboride (MgB2) has been shown to substantially improve its superconducting properties to the levels required for high field magnets, but the doping is difficult to accomplish through the usual route of solid state reaction and diffusion. Further, superconducting cables of MgB2 are difficult to fabricate because of the friable nature of the material. In this Phase I STTR project, doped and undoped boron fibers were made by chemical vapor deposition (CVD). Several >100m long batches of doped and undoped fiber were made by CVD codeposition of boron plus dopants. Bundles of these fibers infiltrated with liquid magnesium and subsequently converted to MgB2 to form Mg-MgB2 metal matrix composites. In a parallel path, doped boron nano-sized powder was produced by a plasma synthesis technique, reacted with magnesium to produce doped MgB2 superconducting ceramic bodies. The doped powder was also fabricated into superconducting wires several meters long. The doped boron fibers and powders made in this program were fabricated into fiber-metal composites and powder-metal composites by a liquid metal infiltration technique. The kinetics of the reaction between boron fiber and magnesium metal was investigated in fiber-metal composites. It was found that the presence of dopants had significantly slowed the reaction between magnesium and boron. The superconducting properties were measured for MgB2 fibers and MgB2 powders made by liquid metal infiltration. Properties of MgB2 products (Jc, Hc2) from Phase I are among the highest reported to date for MgB2 bulk superconductors. Chemically doped MgB2 superconducting magnets can perform at least as well as NbTi and NbSn3 in high magnetic fields and still offer an improvement over the latter two in terms of operating temperature. These characteristics make doped MgB2 an effective material for high magnetic field applications, such as magnetic confined fusion, and medical MRI devices. Developing

  9. Fabrication of Chemically Doped, High Upper Critical Field Magnesium Diboride Superconducting Wires

    Energy Technology Data Exchange (ETDEWEB)

    Marzik, James, V.

    2005-10-13

    Controlled chemical doping of magnesium diboride (MgB2) has been shown to substantially improve its superconducting properties to the levels required for high field magnets, but the doping is difficult to accomplish through the usual route of solid state reaction and diffusion. Further, superconducting cables of MgB2 are difficult to fabricate because of the friable nature of the material. In this Phase I STTR project, doped and undoped boron fibers were made by chemical vapor deposition (CVD). Several >100m long batches of doped and undoped fiber were made by CVD codeposition of boron plus dopants. Bundles of these fibers infiltrated with liquid magnesium and subsequently converted to MgB2 to form Mg-MgB2 metal matrix composites. In a parallel path, doped boron nano-sized powder was produced by a plasma synthesis technique, reacted with magnesium to produce doped MgB2 superconducting ceramic bodies. The doped powder was also fabricated into superconducting wires several meters long. The doped boron fibers and powders made in this program were fabricated into fiber-metal composites and powder-metal composites by a liquid metal infiltration technique. The kinetics of the reaction between boron fiber and magnesium metal was investigated in fiber-metal composites. It was found that the presence of dopants had significantly slowed the reaction between magnesium and boron. The superconducting properties were measured for MgB2 fibers and MgB2 powders made by liquid metal infiltration. Properties of MgB2 products (Jc, Hc2) from Phase I are among the highest reported to date for MgB2 bulk superconductors. Chemically doped MgB2 superconducting magnets can perform at least as well as NbTi and NbSn3 in high magnetic fields and still offer an improvement over the latter two in terms of operating temperature. These characteristics make doped MgB2 an effective material for high magnetic field applications, such as magnetic confined fusion, and medical MRI devices. Developing

  10. structure-chemical analyses of half-antiperovskites and superconductivity of parkerites; Strukturchemische Untersuchungen an Halbantiperowskiten und Supraleitung der Parkerite

    Energy Technology Data Exchange (ETDEWEB)

    Peter, Philipp

    2015-04-22

    The aim of this work was the structural investigation on Halfantiperowskites. In the process four new compounds were synthesized and a new ordering variant was found. Furthermore superconductivity was measured on selected compounds of the Parkerite-type of structure and an attempt was made to change the transition temperature by selective doping.

  11. Highly oriented, free-standing, superconducting NbN films growth on chemical vapor deposited graphene

    Directory of Open Access Journals (Sweden)

    Garima Saraswat

    2014-05-01

    Full Text Available NbN films are grown on chemical vapor deposited graphene using dc magnetron sputtering. The orientation and transition temperature of the deposited films is studied as a function of substrate temperature. A superconducting transition temperature of 14 K is obtained for highly oriented (111 films grown at substrate temperature of 150 °C, which is comparable to epitaxial films grown on MgO and sapphire substrates. These films show a considerably high upper critical field of ∼33 T. In addition, we demonstrate a process for obtaining flexible, free-standing NbN films by delaminating graphene from the substrate using a simple wet etching technique. These free-standing NbN layers can be transferred to any substrate, potentially enabling a range of novel superconducting thin-film applications.

  12. Changes in physico-chemical properties and flavour compounds ...

    African Journals Online (AJOL)

    Four types of Obushera, a fermented millet or sorghum beverage:Ekitiribita Obuteire, Obutoko and Enturire were analyzed for their physico-chemical properties, sugars, organic acids and volatile compounds during fermentation. Standard chemical methods were used to determine the physico-chemical properties of ...

  13. Effects of stoichiometric doping in superconducting Bi-O-S compounds

    Science.gov (United States)

    Morice, Corentin; Artacho, Emilio; Dutton, Siân E.; Molnar, Daniel; Kim, Hyeong-Jin; Saxena, Siddharth S.

    2015-04-01

    Newly discovered Bi-O-S compounds remain an enigma in attempts to understand their electronic properties. A recent study of Bi4O4S3 has shown it to be a mixture of two phases, Bi2OS2 and Bi3O2S3, the latter being superconducting (Phelan et al 2013 J. Am. Chem. Soc. 135 5372-4). Using density functional theory, we explore the electronic structure of both the phases and the effect of the introduction of extra BiS2 bilayers. Our results demonstrate that the S2 layers dope the bismuth-sulphur bands and this causes metallisation. The bands at the Fermi level are of clear two-dimensional character. One band manifold is confined to the two adjacent, square-lattice bismuth-sulphur planes, a second manifold is confined to the square lattice of sulphur dimers. We show that the introduction of extra BiS2 bilayers does not influence the electronic structure. Finally, we also show that spin-orbit coupling does not have any significant effect on the states close to the Fermi level at the energy scale considered.

  14. A new proposal to the mechanism of superconductivity. Pt.2: The elemental and compound superconductors

    International Nuclear Information System (INIS)

    Huang Shiming

    2001-01-01

    There are one or more group of potential-well-like lattice sites for hulun electrons to populate in crystals. The hulun electrons predominately select the deepest and well-shaped wells to populate, and then, the shallower. The population in each group of sites may be full, partial or empty, decided by the offering of hulun electrons. Hulun electrons in each group are in similar circumstance and in same state. They are correlated. They would establish their collective potential and will act as a whole, if no external disturbances or with minor disturbance but collective effect is in predominance. Hulun electrons in different groups are non-correlated. As the external disturbances are increasing the hulun electron groups will collapse one by one from the lower to higher stabilization. The superconducting temperature TC is the one that the most stabilized hulun electron group is in collapsing when the temperature is the only disturbance factor. This proposal is tested by the experimental results published for elemental and compound superconductors

  15. Malaria Parasite Metabolic Pathways (MPMP) Upgraded with Targeted Chemical Compounds.

    Science.gov (United States)

    Ginsburg, Hagai; Abdel-Haleem, Alyaa M

    2016-01-01

    Malaria Parasite Metabolic Pathways (MPMP) is the website for the functional genomics of intraerythrocytic Plasmodium falciparum. All the published information about targeted chemical compounds has now been added. Users can find the drug target and publication details linked to a drug database for further information about the medicinal properties of each compound. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Malaria Parasite Metabolic Pathways (MPMP) Upgraded with Targeted Chemical Compounds

    KAUST Repository

    Ginsburg, Hagai

    2015-10-31

    Malaria Parasite Metabolic Pathways (MPMP) is the website for the functional genomics of intraerythrocytic Plasmodium falciparum. All the published information about targeted chemical compounds has now been added. Users can find the drug target and publication details linked to a drug database for further information about the medicinal properties of each compound.

  17. Study of the superconducting compound Hg,Re-1223 by X-Ray diffraction with application of Rietveld method

    International Nuclear Information System (INIS)

    Putvinskis, Rodrigo

    2008-01-01

    The objective of this work was to study the crystal structure of the superconductor compound of nominal composition Hg 0,82 Re 0,18 Ba 2 Ca 2 Cu 3 O 8+δ and general formula Hg,Re- 1223 and different oxygen contents, by the X-ray diffraction technique, by using the Rietveld method. The studied samples present different oxygen stoichiometry because during the synthesis process, had been heat treated under different oxygen/argon gas mixtures in the ratios: 5:95, 10:90 and 15:85. The results of structural refinement for the samples show that different oxygen contents imply in different cell parameters, atomic positions and distances for the main phase of each sample. The segregation of two superconducting phases with the same crystal structure, but slightly different cell parameters was confirmed for the studied samples both by Rietveld analysis and anomalous X-ray diffraction experiments. It was also confirmed that one of the segregated phases does not incorporate Re cations its composition. The main phase, who incorporates the Re cations, is here called Hg,Re-1223 and the Re-free secondary phase is called Hg- 1223. It was found that the superconducting phases present different crystallite sizes and the sample treated under gas flow composed of 10% oxygen and 90% argon presents the highest fraction of superconducting phases. From these results it was possible to conclude that the sample produced from the precursor compound treated under flow of O 2 /Ar gas at the ratio 10/90 presents the better results for the synthesis of this superconducting compound. (author)

  18. Method and system for controlling chemical reactions between superconductors and metals in superconducting cables

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Tengming

    2018-01-02

    A method, system, and apparatus for fabricating a high-strength Superconducting cable comprises pre-oxidizing at least one high-strength alloy wire, coating at least one Superconducting wire with a protective layer, and winding the high-strength alloy wire and the Superconducting wire to form a high-strength Superconducting cable.

  19. Method and system for controlling chemical reactions between superconductors and metals in superconducting cables

    Science.gov (United States)

    Shen, Tengming

    2016-11-15

    A method, system, and apparatus for fabricating a high-strength Superconducting cable comprises pre-oxidizing at least one high-strength alloy wire, coating at least one Superconducting wire with a protective layer, and winding the high-strength alloy wire and the Superconducting wire to form a high-strength Superconducting cable.

  20. Exploration of stable compounds, crystal structures, and superconductivity in the Be-H system

    Directory of Open Access Journals (Sweden)

    Shuyin Yu

    2014-10-01

    Full Text Available Using first-principles variable-composition evolutionary methodology, we explored the high-pressure structures of beryllium hydrides between 0 and 400 GPa. We found that BeH2 remains the only stable compound in this pressure range. The pressure-induced transformations are predicted as I b a m → P 3 ̄ m 1 → R 3 ̄ m → C m c m → P 4 / n m m , which occur at 24, 139, 204 and 349 GPa, respectively. P 3 ̄ m 1 and R 3 ̄ m structures are layered polytypes based on close packings of H atoms with Be atoms filling all octahedral voids in alternating layers. Cmcm and P4/nmm contain two-dimensional triangular networks with each layer forming a kinked slab in the ab-plane. P 3 ̄ m 1 and R 3 ̄ m are semiconductors while Cmcm and P4/nmm are metallic. We have explored superconductivity of both metal phases, and found large electron-phonon coupling parameters of λ = 0.63 for Cmcm with a Tc of 32.1-44.1 K at 250 GPa and λ = 0.65 for P4/nmm with a Tc of 46.1-62.4 K at 400 GPa. The dependence of Tc on pressure indicates that Tc initially increases to a maximum of 45.1 K for Cmcm at 275 GPa and 97.0 K for P4/nmm at 365 GPa, and then decreases with increasing pressure for both phases.

  1. High pressure superconductivity in iron-based layered compounds studied using designer diamonds.

    Science.gov (United States)

    Tsoi, Georgiy; Stemshorn, Andrew K; Vohra, Yogesh K; Wu, Phillip M; Hsu, F C; Huang, Y L; Wu, M K; Yeh, K W; Weir, Samuel T

    2009-06-10

    High pressure superconductivity in iron-based superconductor FeSe(0.5)Te(0.5) has been studied up to 15 GPa and 10 K using an eight probe designer diamond anvil in a diamond anvil cell device. Four probe electrical resistance measurements show the onset of superconductivity (T(c)) at 14 K at ambient pressure with T(c) increasing with increasing pressure to 19 K at a pressure of 3.6 GPa. At higher pressures beyond 3.6 GPa, T(c) decreases and extrapolation suggests non-superconducting behavior above 10 GPa. The loss of superconductivity coincides with the pressure induced disordering of the Fe(SeTe)(4) tetrahedra reported at 11 GPa in x-ray diffraction studies at ambient temperature.

  2. Magnetic ordering at low temperatures in some random superconducting and insulating compounds

    International Nuclear Information System (INIS)

    Hueser, D.

    1985-01-01

    This thesis presents the results of some investigations on the magnetic ordering phenomena in some random superconducting and insulating materials. The results are described of an investigation of the coexistence of superconductivity and random magnetic freezing in (Th,Nd)Ru 2 . On the basis of various measurements as function of temperature and external magnetic field the author found that spin glass-like freezing can occur far below the superconductivity and even that a sample may re-enter the superconducting state below a freezing temperature. Associated with the isothermal remanent magnetization of a random magnetic material he observed strong anomalies in the critical field versus temperature curves. Also a magnetic field memory effect has been found. (Auth.)

  3. Fate modelling of chemical compounds with incomplete data sets

    DEFF Research Database (Denmark)

    Birkved, Morten; Heijungs, Reinout

    2011-01-01

    , and to provide simplified proxies for the more complicated “real”model relationships. In the presented study two approaches for the reduction of the data demand associated with characterization of chemical emissions in USEtoxTM are tested: The first approach yields a simplified set of mode of entry specific meta......Impact assessment of chemical compounds in Life Cycle Impact Assessment (LCIA) and Environmental Risk Assessment (ERA) requires a vast amount of data on the properties of the chemical compounds being assessed. These data are used in multi-media fate and exposure models, to calculate risk levels...... in an approximate way. The idea is that not all data needed in a multi-media fate and exposure model are completely independent and equally important, but that there are physical-chemical and biological relationships between sets of chemical properties. A statistical model is constructed to underpin this assumption...

  4. Portable Sensor for Chemical Nerve Agents and Organophosphorus Compounds

    Science.gov (United States)

    2015-08-18

    Spectroscopy Highlights 1) The synthesis and modification of zirconium gel with ß-cyclodextrin (ZrO2-ß-CD) via sol-gel process have been...agricultural as pesticides in the US and worldwide. These compounds are neurotoxins which can breakdown neurotransmitter acetylcholine at the neural synapse...the synthesis , fabrication, and characterization of chemical sensor thin film for the detection of organophosphate compounds (OP) and pesticides. The

  5. Superconducting gap structure of heavy-Fermion compound URu2Si2 determined by angle-resolved thermal conductivity

    Science.gov (United States)

    Kasahara, Y.; Shishido, H.; Shibauchi, T.; Haga, Y.; Matsuda, T. D.; Onuki, Y.; Matsuda, Y.

    2009-05-01

    In heavy-Fermion compound URu2Si2, unusual superconductivity is embedded in an enigmatic 'hidden order' phase. Recently, it has been shown that URu2Si2 is essentially a multiband superconductor associated with the semimetallic compensated electronic structure. Here, to pin down the detailed superconducting gap structure, we have performed thermal transport measurements on ultraclean URu2Si2 single crystals in magnetic fields rotating various directions relative to the crystal axes. By changing the amplitude of magnetic fields, we determined the nodal topology of electron and hole band separately. The results indicate a new type of unconventional superconductivity with two distinct gaps, in which horizontal line nodes lie within the basal ab plane of the light-hole band with small gap and point nodes along the c-axis in the heavy electron band with large gap. This gap structure is consistent with 'chiral' d-wave symmetry with a form {\\hat{k}}_{z}({\\hat{k}}_{x}+i{\\hat{k}}_{y}) .

  6. Superconducting gap structure of heavy-Fermion compound URu2Si2 determined by angle-resolved thermal conductivity

    International Nuclear Information System (INIS)

    Kasahara, Y; Shishido, H; Shibauchi, T; Matsuda, Y; Haga, Y; Matsuda, T D; Onuki, Y

    2009-01-01

    In heavy-Fermion compound URu 2 Si 2 , unusual superconductivity is embedded in an enigmatic 'hidden order' phase. Recently, it has been shown that URu 2 Si 2 is essentially a multiband superconductor associated with the semimetallic compensated electronic structure. Here, to pin down the detailed superconducting gap structure, we have performed thermal transport measurements on ultraclean URu 2 Si 2 single crystals in magnetic fields rotating various directions relative to the crystal axes. By changing the amplitude of magnetic fields, we determined the nodal topology of electron and hole band separately. The results indicate a new type of unconventional superconductivity with two distinct gaps, in which horizontal line nodes lie within the basal ab plane of the light-hole band with small gap and point nodes along the c-axis in the heavy electron band with large gap. This gap structure is consistent with 'chiral' d-wave symmetry with a form k-circumflex z (k-circumflex x +ik-circumflex y ).

  7. Sensitivity of animals to chemical compounds links to metabolic rate.

    NARCIS (Netherlands)

    Baas, J.; Kooijman, S.A.L.M.

    2015-01-01

    Ecotoxicological studies have shown considerable variation in species sensitivity for chemical compounds, but general patterns in sensitivity are still not known. A better understanding of this sensitivity is important in the context of environmental risk assessment but also in a more general

  8. Determination of borneol and other chemical compounds of ...

    African Journals Online (AJOL)

    Purpose: To determine borneol and other chemical compounds of essential oil derived from the exudate of Dryobalanops aromatica in Malaysia. Methods: Exudate was collected from D. aromatica and subjected to fractional distillation to obtain essential oil. Gas chromatography-mass spectrometry (GC-MS) was performed ...

  9. Chemical evaluation of protein quality and phenolic compound ...

    African Journals Online (AJOL)

    This work studies the chemical evaluation of protein quality and phenolic compound contents of some Cucurbitaceae (egusi) oilseeds from different areas in Cameroon. These seeds are Cucumeropsis mannii, Cucurbita maxima, Cucurbita moschata, Lagenaria siceraria and Cucumis sativus. The seeds were cleaned, dried, ...

  10. The implications of agro-chemical compounds (fertilizers, pesticides ...

    African Journals Online (AJOL)

    The implications of agro-chemical compounds (fertilizers, pesticides and herbicides) on farming/aquaculture activities in the lake-Chad and its possible ... The results of the experiment indicated that five parameters, namely, PH, Cadmium, Iron, Magnesium and chlorine have contaminant levels above the threshold limit as ...

  11. Three Packets of Minerals of the Periodic Table of Chemical Elements and Chemical Compounds

    OpenAIRE

    Labushev, Mikhail M.

    2013-01-01

    The concepts of alpha- and beta-packets of the periodic table of chemical elements and chemical compounds are defined. The first of the 47 minerals alpha-packets is composed. In it all minerals are arranged in increasing Iav index of proportionality of atomic weights of composing chemical elements, the same way as chemical elements are located in increasing atomic weights in the Periodic table. The packet includes 93 known minerals and two compounds - N2O5 and CO2 - being actually minerals. B...

  12. In-situ growth of YBCO high- Tc superconducting thin films by plasma-enhanced metalorganic chemical vapor deposition

    Science.gov (United States)

    Zhao, J.; Chern, C. S.; Li, Y. Q.; Noh, D. W.; Norris, P. E.; Zawadzki, P.; Kear, B.; Gallois, B.

    1991-01-01

    Highly c-axis oriented, highly dense, low carbon YBa 2Cu 3O x superconducting thin films have been formed in-situ at a reduced substrate temperature as low as 570°C by a novel plasma enhanced metalorganic chemical vapor deposition process. Superconducting YBa 2Cu 3O x thin films, having a zero resistance transition temperature of 82 K and critical current density of 10 4A/cm 2 at 70 K have been directly deposited on sapphire substrates by such a process.

  13. On possibility origination of superconductivity in MgB sub 2 compound

    CERN Document Server

    Zajtsev, R O

    2001-01-01

    The mechanism of originating superconductivity in the MgB sub 2 is studied on the basis of the Hubbard generalized model. The possibility of existence of the Cooper instability in the system with jumps between the cations and anions of the nontransient elements is established with application of the notion on the strong interaction. Filling of the boron four electron p-shell and the magnesium two-electron 3s sup 2 shell is considered with an account of the hexagonal symmetry of the MgB sub 2 elementary cell. The phase diagram of existing the superconductivity in dependence on the filling rate of the (n sub p)p sup 6 and (n sub s)s sup 2 -shells of the nontransient elements is plotted

  14. Magnetic and structural features of RNi2B2C and RNiBC (R=Er, Ho, Dy, Tb, Gd) superconducting compounds

    OpenAIRE

    Baggio-Saitovitch, E. M.; Sánchez, D. R.; Micklitz, H.

    2002-01-01

    Temperature dependent Mössbauer spectroscopy on 57Fe doped (1 at % of Ni) RNi2B2C and RNiBC provided clear evidence of a pair-breaking field at the Ni site for non-superconducting compounds. This field is not present in the superconducting collinear AF DyNi2B2C, however it appears when this compound is diluted with non-magnetic Lu (Dy1-xLu xNi2B2C). Important local information on the spin structure of the R magnetic moments is obtained for both systems. The local symmetries of RNi2B2C and RNi...

  15. Antifungal chemical compounds identified using a C. elegans pathogenicity assay.

    Directory of Open Access Journals (Sweden)

    Julia Breger

    2007-02-01

    Full Text Available There is an urgent need for the development of new antifungal agents. A facile in vivo model that evaluates libraries of chemical compounds could solve some of the main obstacles in current antifungal discovery. We show that Candida albicans, as well as other Candida species, are ingested by Caenorhabditis elegans and establish a persistent lethal infection in the C. elegans intestinal track. Importantly, key components of Candida pathogenesis in mammals, such as filament formation, are also involved in nematode killing. We devised a Candida-mediated C. elegans assay that allows high-throughput in vivo screening of chemical libraries for antifungal activities, while synchronously screening against toxic compounds. The assay is performed in liquid media using standard 96-well plate technology and allows the study of C. albicans in non-planktonic form. A screen of 1,266 compounds with known pharmaceutical activities identified 15 (approximately 1.2% that prolonged survival of C. albicans-infected nematodes and inhibited in vivo filamentation of C. albicans. Two compounds identified in the screen, caffeic acid phenethyl ester, a major active component of honeybee propolis, and the fluoroquinolone agent enoxacin exhibited antifungal activity in a murine model of candidiasis. The whole-animal C. elegans assay may help to study the molecular basis of C. albicans pathogenesis and identify antifungal compounds that most likely would not be identified by in vitro screens that target fungal growth. Compounds identified in the screen that affect the virulence of Candida in vivo can potentially be used as "probe compounds" and may have antifungal activity against other fungi.

  16. Alternative superconducting systems

    International Nuclear Information System (INIS)

    1992-01-01

    In the context of the experiment on 'Development of high temperature superconducting system components' supported by the German Ministry of Research and Technology, investigations were carried out by the Working Party of Prof. von Schnering at the Max Planck Institute for Solids Research, the aim of which is to find characteristic structural features of superconducting substances. Alternative systems are to be looked for with the aid of correlation of superconducting properties with simple electronic and chemical structure models, where very powerful 3D computer graphics are used to visualize them. The theoretical and information technology part of the work was supplemented by experiments. Superconducting phases and related compounds were represented and their structures and physical properties were determined. According to the tasks described above, the report is divided into three sections. Starting with the description of a program system for three-dimensional representation of structures and properties of periodic systems, in the second section a process for calculating node surfaces is explained and the importance of curvature in chemical structures is pointed out. The results of the experiments are collected in the third part. (orig.) [de

  17. Superconducting properties of Zr1+xNi2-xGa and Zr1-xNi2+xGa Heusler compounds

    Directory of Open Access Journals (Sweden)

    Saad Alzahrani

    2017-05-01

    Full Text Available The superconducting properties of a series of Zr1+xNi2-xGa and Zr1-xNi2+xGa compounds have been investigated by x-ray diffraction, electrical resistivity, dc magnetization, and ac susceptibility measurements. While the parent compound, ZrNi2Ga, exhibited the cubic L21 Heusler structure, multiple non-cubic structures formed in the Zr and Ni rich doped materials. For x ≤ 0.3, all Zr1-xNi2+xGa compounds demonstrated superconducting behavior, but no superconductivity was observed in the Zr1+xNi2-xGa alloys for x > 0.2. The magnetization data revealed that all materials in both Zr1+xNi2-xGa and Zr1-xNi2+xGa series exhibited type-II superconductivity. With increasing doping concentration x, the paramagnetic ordering were enhanced in both systems while the superconducting properties were found to weaken. The observations are discussed considering the structural disorders in the systems.

  18. QSAR modeling and chemical space analysis of antimalarial compounds

    Science.gov (United States)

    Sidorov, Pavel; Viira, Birgit; Davioud-Charvet, Elisabeth; Maran, Uko; Marcou, Gilles; Horvath, Dragos; Varnek, Alexandre

    2017-05-01

    Generative topographic mapping (GTM) has been used to visualize and analyze the chemical space of antimalarial compounds as well as to build predictive models linking structure of molecules with their antimalarial activity. For this, a database, including 3000 molecules tested in one or several of 17 anti- Plasmodium activity assessment protocols, has been compiled by assembling experimental data from in-house and ChEMBL databases. GTM classification models built on subsets corresponding to individual bioassays perform similarly to the earlier reported SVM models. Zones preferentially populated by active and inactive molecules, respectively, clearly emerge in the class landscapes supported by the GTM model. Their analysis resulted in identification of privileged structural motifs of potential antimalarial compounds. Projection of marketed antimalarial drugs on this map allowed us to delineate several areas in the chemical space corresponding to different mechanisms of antimalarial activity. This helped us to make a suggestion about the mode of action of the molecules populating these zones.

  19. QSAR modeling and chemical space analysis of antimalarial compounds.

    Science.gov (United States)

    Sidorov, Pavel; Viira, Birgit; Davioud-Charvet, Elisabeth; Maran, Uko; Marcou, Gilles; Horvath, Dragos; Varnek, Alexandre

    2017-05-01

    Generative topographic mapping (GTM) has been used to visualize and analyze the chemical space of antimalarial compounds as well as to build predictive models linking structure of molecules with their antimalarial activity. For this, a database, including ~3000 molecules tested in one or several of 17 anti-Plasmodium activity assessment protocols, has been compiled by assembling experimental data from in-house and ChEMBL databases. GTM classification models built on subsets corresponding to individual bioassays perform similarly to the earlier reported SVM models. Zones preferentially populated by active and inactive molecules, respectively, clearly emerge in the class landscapes supported by the GTM model. Their analysis resulted in identification of privileged structural motifs of potential antimalarial compounds. Projection of marketed antimalarial drugs on this map allowed us to delineate several areas in the chemical space corresponding to different mechanisms of antimalarial activity. This helped us to make a suggestion about the mode of action of the molecules populating these zones.

  20. Physical and Chemical Aspects of Stabilization of Compounds in Silk

    Science.gov (United States)

    Pritchard, Eleanor M.; Dennis, Patrick B.; Omenetto, Fiorenzo; Naik, Rajesh R.; Kaplan, David L.

    2015-01-01

    The challenge of stabilization of small molecules and proteins has received considerable interest. The biological activity of small molecules can be lost as a consequence of chemical modifications, while protein activity may be lost due to chemical or structural degradation, such as a change in macromolecular conformation or aggregation. In these cases stabilization is required to preserve therapeutic and bioactivity efficacy and safety. In addition to use in therapeutic applications, strategies to stabilize small molecules and proteins also have applications in industrial processes, diagnostics, and consumer products like food and cosmetics. Traditionally, therapeutic drug formulation efforts have focused on maintaining stability during product preparation and storage. However, with growing interest in the fields of encapsulation, tissue engineering and controlled release drug delivery systems, new stabilization challenges are being addressed; the compounds or protein of interest must be stabilized during: (1) fabrication of the protein or small molecule loaded carrier, (2) device storage, and (3) for the duration of intended release needs in vitro or in vivo. We review common mechanisms of compound degradation for small molecules and proteins during biomaterial preparation (including tissue engineering scaffolds and drug delivery systems), storage and in vivo implantation. We also review the physical and chemical aspects of polymer-based stabilization approaches, with a particular focus on the stabilizing properties of silk fibroin biomaterials. PMID:22270942

  1. MBROLE 2.0-functional enrichment of chemical compounds.

    Science.gov (United States)

    López-Ibáñez, Javier; Pazos, Florencio; Chagoyen, Mónica

    2016-07-08

    Metabolites Biological Role (MBROLE) is a server that performs functional enrichment analysis of a list of chemical compounds derived from a metabolomics experiment, which allows this list to be interpreted in biological terms. Since its release in 2011, MBROLE has been used by different groups worldwide to analyse metabolomics experiments from a variety of organisms. Here we present the latest version of the system, MBROLE2, accessible at http://csbg.cnb.csic.es/mbrole2 MBROLE2 has been supplemented with 10 databases not available in the previous version, which allow analysis over a larger, richer set of vocabularies including metabolite-protein and drug-protein interactions. This new version performs automatic conversion of compound identifiers from different databases, thus simplifying usage. In addition, the user interface has been redesigned to generate an interactive, more intuitive representation of the results. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  2. Chemical Composition and Bioactive Compounds of Some Wild Edible Mushrooms

    Directory of Open Access Journals (Sweden)

    Melinda NAGY

    2017-05-01

    Full Text Available Over the last decades, the consumption of mushrooms has significantly increased due to the scientific evidence of their ability to help the organism in the combat and prevention of several diseases (Kalac, 2009. Fruiting bodies of mushrooms are consumed as a delicacy for their texture and flavour, but also for their nutritional properties that makes them even more attractable (Heleno S. 2015. In this paper data were collected from several scientific studies with the aim to characterize the chemical composition and content of bioactive compounds of various mushrooms species: Agaricus bisporus, Boletus edulis, Cantharellus cibarius, Pleurotus ostreatus, Lactarius piperatus. The chemical composition of 5 wild edible studied mushrooms, including moisture, ash, total carbohydrates, total sugars, crude fat, crude protein and energy were determined according to AOAC procedures.

  3. How to tackle chemical communication? Relative proportions versus semiquantitative determination of compounds in lizard chemical secretions.

    Science.gov (United States)

    García-Roa, Roberto; Sáiz, Jorge; Gómara, Belén; López, Pilar; Martín, José

    2018-02-01

    Knowledge about chemical communication in some vertebrates is still relatively limited. Squamates are a glaring example of this, even when recent evidences indicate that scents are involved in social and sexual interactions. In lizards, where our understanding of chemical communication has considerably progressed in the last few years, many questions about chemical interactions remain unanswered. A potential reason for this is the inherent complexity and technical limitations that some methodologies embody when analyzing the compounds used to convey information. We provide here a straightforward procedure to analyze lizard chemical secretions based on gas chromatography coupled to mass spectrometry that uses an internal standard for the semiquantification of compounds. We compare the results of this method with those obtained by the traditional procedure of calculating relative proportions of compounds. For such purpose, we designed two experiments to investigate if these procedures allowed revealing changes in chemical secretions 1) when lizards received previously a vitamin dietary supplementation or 2) when the chemical secretions were exposed to high temperatures. Our results show that the procedure based on relative proportions is useful to describe the overall chemical profile, or changes in it, at population or species levels. On the other hand, the use of the procedure based on semiquantitative determination can be applied when the target of study is the variation in one or more particular compounds of the sample, as it has proved more accurate detecting quantitative variations in the secretions. This method would reveal new aspects produced by, for example, the effects of different physiological and climatic factors that the traditional method does not show.

  4. Characterizations of power loads on divertor targets for type-I, compound and small ELMs in the EAST superconducting tokamak

    DEFF Research Database (Denmark)

    Wang, L.; Xu, G.S.; Guo, H.Y.

    2013-01-01

    -III ELMy H-modes. The energy loss and divertor power load are systematically characterized for these different ELMy H-modes to provide a physics basis for the next-step high-power long-pulse operations in EAST. Both type-I and compound ELMs exhibit good confinement (H98(y,2) ∼ 1). A significant loss......The Experimental Advanced Superconducting Tokamak (EAST) has recently achieved a variety of H-mode regimes with different edge-localized mode (ELM) dynamics, including type-I ELMs, compound ELMs, which are manifested by the onset of a large spike followed by a sequence of small spikes on Dα......-III ELMs. It is remarkable that the new very small ELMy H-modes exhibit even lower target power deposition than type-III ELMs, with the peak heat flux generally below 1 MW m−2. These very small ELMs are usually accompanied by broadband fluctuations with frequencies ranging from 20 to 50 kHz, which may...

  5. Electronic Correlations, Jahn-Teller Distortions and Mott Transition to Superconductivity in Alkali-C60 Compounds

    Directory of Open Access Journals (Sweden)

    Alloul H.

    2012-03-01

    Full Text Available The discovery in 1991 of high temperature superconductivity (SC in A3C60 compounds, where A is an alkali ion, has been rapidly ascribed to a BCS mechanism, in which the pairing is mediated by on ball optical phonon modes. While this has lead to consider that electronic correlations were not important in these compounds, further studies of various AnC60 with n=1, 2, 4 allowed to evidence that their electronic properties cannot be explained by a simple progressive band filling of the C60 six-fold degenerate t1u molecular level. This could only be ascribed to the simultaneous influence of electron correlations and Jahn-Teller Distortions (JTD of the C60 ball, which energetically favour evenly charged C60 molecules. This is underlined by the recent discovery of two expanded fulleride Cs3C60 isomeric phases which are Mott insulators at ambient pressure. Both phases undergo a pressure induced first order Mott transition to SC with a (p, T phase diagram displaying a dome shaped SC, a common situation encountered nowadays in correlated electron systems. NMR experiments allowed us to study the magnetic properties of the Mott phases and to evidence clear deviations from BCS expectations near the Mott transition. So, although SC involves an electron-phonon mechanism, the incidence of electron correlations has an importance on the electronic properties, as had been anticipated from DMFT calculations.

  6. Preparation, crystal structure and physical properties of the superconducting cage compound Ba{sub 3}Ge{sub 16}Ir{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Duong Nguyen, Hong; Prots, Yurii; Schnelle, Walter; Boehme, Bodo; Baitinger, Michael; Grin, Yuri [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Str. 40, 01187 Dresden (Germany); Paschen, Silke [Institut fuer Festkoerperphysik, Technische Universitaet Wien, Wiedner Hauptstrasse 8-10, 1040 Wien (Austria)

    2014-04-15

    The cage compound Ba{sub 3}Ge{sub 16}Ir{sub 4} crystallizes with the Ba{sub 3}Ge{sub 16}Rh{sub 4} type of crystal structure, which represents a hierarchical derivative of the BaAl{sub 4} type. The crystal structure [Pearson symbol tI46, space group I4/mmm; a = 6.5312(2) Aa, c = 22.2845(6) Aa] was refined from single-crystal X-ray diffraction data. The phase was obtained after 10 d at 910 C with small impurities of clathrate-I, BaGe{sub 7}Ir{sub 2} and α-Ge remaining at the grain boundaries. Ba{sub 3}Ge{sub 16}Ir{sub 4} is a Pauli-paramagnetic metal, which becomes superconducting below T{sub c} = 5.1 K. Electronic structure and analysis of the chemical bonding were performed based on density functional theory calculations. The physical properties are discussed in comparison to the isotypic phase Ba{sub 3}Ge{sub 16}Rh{sub 4}. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Superconductivity in the actinides

    International Nuclear Information System (INIS)

    Smith, J.L.; Lawson, A.C.

    1985-01-01

    The trends in the occurrence of superconductivity in actinide materials are discussed. Most of them seem to show simple transition metal behavior. However, the superconductivity of americium proves that the f electrons are localized in that element and that ''actinides'' is the correct name for this row of elements. Recently the superconductivity of UBe 13 and UPt 3 has been shown to be extremely unusual, and these compounds fall in the new class of compounds now known as heavy fermion materials

  8. Superconductivity at 43 K in an iron-based layered compound LaO(1-x)F(x)FeAs.

    Science.gov (United States)

    Takahashi, Hiroki; Igawa, Kazumi; Arii, Kazunobu; Kamihara, Yoichi; Hirano, Masahiro; Hosono, Hideo

    2008-05-15

    The iron- and nickel-based layered compounds LaOFeP (refs 1, 2) and LaONiP (ref. 3) have recently been reported to exhibit low-temperature superconducting phases with transition temperatures T(c) of 3 and 5 K, respectively. Furthermore, a large increase in the midpoint T(c) of up to approximately 26 K has been realized in the isocrystalline compound LaOFeAs on doping of fluoride ions at the O2- sites (LaO(1-x)F(x)FeAs). Experimental observations and theoretical studies suggest that these transitions are related to a magnetic instability, as is the case for most superconductors based on transition metals. In the copper-based high-temperature superconductors, as well as in LaOFeAs, an increase in T(c) is often observed as a result of carrier doping in the two-dimensional electronic structure through ion substitution in the surrounding insulating layers, suggesting that the application of external pressure should further increase T(c) by enhancing charge transfer between the insulating and conducting layers. The effects of pressure on these iron oxypnictide superconductors may be more prominent than those in the copper-based systems, because the As ion has a greater electronic polarizability, owing to the covalency of the Fe-As chemical bond, and, thus, is more compressible than the divalent O2- ion. Here we report that increasing the pressure causes a steep increase in the onset T(c) of F-doped LaOFeAs, to a maximum of approximately 43 K at approximately 4 GPa. With the exception of the copper-based high-T(c) superconductors, this is the highest T(c) reported to date. The present result, together with the great freedom available in selecting the constituents of isocrystalline materials with the general formula LnOTMPn (Ln, Y or rare-earth metal; TM, transition metal; Pn, group-V, 'pnicogen', element), indicates that the layered iron oxypnictides are promising as a new material platform for further exploration of high-temperature superconductivity.

  9. Antifoaming effect of chemical compounds in manure biogas reactors.

    Science.gov (United States)

    Kougias, P G; Tsapekos, P; Boe, K; Angelidaki, I

    2013-10-15

    A precise and efficient antifoaming control strategy in bioprocesses is a challenging task as foaming is a very complex phenomenon. Nevertheless, foam control is necessary, as foam is a major operational problem in biogas reactors. In the present study, the effect of 14 chemical compounds on foam reduction was evaluated at concentration of 0.05%, 0.1% and 0.5% v/v(sample), in raw and digested manure. Moreover, two antifoam injection methods were compared for foam reduction efficiency. Natural oils (rapeseed and sunflower oil), fatty acids (oleic, octanoic and derivative of natural fatty acids), siloxanes (polydimethylsiloxane) and ester (tributylphosphate) were found to be the most efficient compounds to suppress foam. The efficiency of antifoamers was dependant on their physicochemical properties and greatly correlated to their chemical characteristics for dissolving foam. The antifoamers were more efficient in reducing foam when added directly into the liquid phase rather than added in the headspace of the reactor. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. High temperature superconductivity: Concept, preparation and testing of high Tc superconductor compounds, and applications

    International Nuclear Information System (INIS)

    Harara, Wafik

    1992-06-01

    Many studies have been carried out on high temperature superconductors with transition temperature above that of the liquid nitrogen. In this scientific study the concept and the mechanism of this phenomena are discussed, in addition the examples of preparation and testing of high temperature superconductors compounds are shown. Also the most important applications in industry are explained. (author). 15 refs., 2 tabs., 18 figs

  11. Process for optimization of superconductivity properties of YBa2Cu307-δ compounds

    International Nuclear Information System (INIS)

    Perrin, A.M.Y.; Pena-Alvarez, O.; Perrin, C.; Sergent, M.; Le Traon, J.Y.

    1988-01-01

    After obtention the YBaCu0 compound (where Y can be replaced partially or completely by Sc and/or Ba by Sr) is thermally treated in the temperature range 360-500 0 C in an atmosphere containing oxygen [fr

  12. Superconductivity above 90K in the Y-Ba-Cu-O compound system

    International Nuclear Information System (INIS)

    Paterno, G.; Balestrino, G.; Barbanera, S.

    1987-01-01

    Preliminary results on high Tc superconductors are reported. One of Y-Ba-Cu-O compound system has been fabricated. The temperature dependence of the resistance has been determined. The critical temperature of the samples annealed in Oxygen atmosphere is well above the normal boiling point of liquid nitrogen

  13. Superconducting material development

    Science.gov (United States)

    1987-09-01

    A superconducting compound was developed that showed a transition to a zero-resistance state at 65 C, or 338 K. The superconducting material, which is an oxide based on strontium, barium, yttrium, and copper, continued in the zero-resistance state similar to superconductivity for 10 days at room temperature in the air. It was also noted that measurements of the material allowed it to observe a nonlinear characteristic curve between current and voltage at 65 C, which is another indication of superconductivity. The research results of the laboratory experiment with the superconducting material will be published in the August edition of the Japanese Journal of Applied Physics.

  14. Chemical compounds of the foraging recruitment pheromone in bumblebees

    Science.gov (United States)

    Granero, Angeles Mena; Sanz, José M. Guerra; Gonzalez, Francisco J. Egea; Vidal, José L. Martinez; Dornhaus, Anna; Ghani, Junaid; Serrano, Ana Roldán; Chittka, Lars

    2005-08-01

    When the frenzied and irregular food-recruitment dances of bumblebees were first discovered, it was thought that they might represent an evolutionary prototype to the honeybee waggle dance. It later emerged that the primary function of the bumblebee dance was the distribution of an alerting pheromone. Here, we identify the chemical compounds of the bumblebee recruitment pheromone and their behaviour effects. The presence of two monoterpenes and one sesquiterpene (eucalyptol, ocimene and farnesol) in the nest airspace and in the tergal glands increases strongly during foraging. Of these, eucalyptol has the strongest recruitment effect when a bee nest is experimentally exposed to it. Since honeybees use terpenes for marking food sources rather than recruiting foragers inside the nest, this suggests independent evolutionary roots of food recruitment in these two groups of bees.

  15. Mitochondrial Functionality and Chemical Compound Action on Sperm Function.

    Science.gov (United States)

    Amaral, S; S Tavares, R; Baptista, M; Sousa, M I; Silva, A; Escada-Rebelo, S; Paiva, C P; Ramalho-Santos, J

    2016-01-01

    During the last decade, several studies have shown that mitochondrial parameters, such as integrity, respiratory activity, membrane potential and ROS production are intimately linked with sperm quality. Given the limitations of conventional semen analyses in terms of predicting male fertility, an increasing number of studies are focusing on the characterization of sperm mitochondria in order to more accurately assess sperm functionality. Moreover, mitochondria from several organs, such as the liver, have been described as a powerful screening tool for drug safety, being an easy in vitro model to assess the toxicity of distinct families of compounds. Given that mitochondrial functionality is intimately related to sperm homeostasis, it has become important to understand how compounds, ranging from dietary supplements, environmental pollutants, dependency-inducing drugs to pharmacological agents (such as erectile dysfunction-targeted drugs and male contraceptives) affect sperm mitochondrial function. In this review, we discuss studies describing the effects of various chemical agents on spermatozoa, with particular emphasis on mitochondrial function. From the extensive literature analyzed, we conclude that in some cases the role of sperm mitochondria as putative predictors of sperm functionality is very obvious, while in others further studies are needed to clarify this issue.

  16. Superconductivity in transition metals.

    Science.gov (United States)

    Slocombe, Daniel R; Kuznetsov, Vladimir L; Grochala, Wojciech; Williams, Robert J P; Edwards, Peter P

    2015-03-13

    A qualitative account of the occurrence and magnitude of superconductivity in the transition metals is presented, with a primary emphasis on elements of the first row. Correlations of the important parameters of the Bardeen-Cooper-Schrieffer theory of superconductivity are highlighted with respect to the number of d-shell electrons per atom of the transition elements. The relation between the systematics of superconductivity in the transition metals and the periodic table high-lights the importance of short-range or chemical bonding on the remarkable natural phenomenon of superconductivity in the chemical elements. A relationship between superconductivity and lattice instability appears naturally as a balance and competition between localized covalent bonding and so-called broken covalency, which favours d-electron delocalization and superconductivity. In this manner, the systematics of superconductivity and various other physical properties of the transition elements are related and unified. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  17. Mapping of the Available Chemical Space versus the Chemical Universe of Lead-Like Compounds.

    Science.gov (United States)

    Lin, Arkadii; Horvath, Dragos; Afonina, Valentina; Marcou, Gilles; Reymond, Jean-Louis; Varnek, Alexandre

    2018-03-20

    This is, to our knowledge, the most comprehensive analysis to date based on generative topographic mapping (GTM) of fragment-like chemical space (40 million molecules with no more than 17 heavy atoms, both from the theoretically enumerated GDB-17 and real-world PubChem/ChEMBL databases). The challenge was to prove that a robust map of fragment-like chemical space can actually be built, in spite of a limited (≪10 5 ) maximal number of compounds ("frame set") usable for fitting the GTM manifold. An evolutionary map building strategy has been updated with a "coverage check" step, which discards manifolds failing to accommodate compounds outside the frame set. The evolved map has a good propensity to separate actives from inactives for more than 20 external structure-activity sets. It was proven to properly accommodate the entire collection of 40 m compounds. Next, it served as a library comparison tool to highlight biases of real-world molecules (PubChem and ChEMBL) versus the universe of all possible species represented by FDB-17, a fragment-like subset of GDB-17 containing 10 million molecules. Specific patterns, proper to some libraries and absent from others (diversity holes), were highlighted. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Chemical Compounds Recovery in Carboxymethyl Cellulose Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    P.-H. Rao

    2015-05-01

    Full Text Available Carboxymethyl cellulose (CMC is a kind of cellulose ether widely used in industrial production. CMC wastewater usually have high chemical oxygen demand (COD and salinity (>10 %, which result from organic and inorganic by-products during CMC production. It is significant that the wastewater is pretreated to decrease salinity and recover valuable organics before biochemical methods are employed. In this paper, distillation-extraction method was used to pretreat CMC wastewater and recover valuable chemical compounds from wastewater (Fig. 1. Initial pH of CMC wastewater was adjusted to different values (6.5, 8.5, 9.5, 10.5, 12.0 before distillation to study the effect of pH on by-products in wastewater. By-products obtained from CMC wastewater were extracted and characterized by NMR, XRD and TGA. Distillate obtained from distillation of wastewater was treated using biological method, i.e., upflow anaerobic sludge blanket (UASB-contact oxidation process. Domestic sewage and flushing water from manufacturing shop was added into distillate to decrease initial COD and increase nutrients such as N, P, K. Experimental results showed that by-products extracted from CMC wastewater mainly include ethoxyacetic acid and NaCl, which were confirmed by NMR and XRD (Fig. 2. TGA results of by-products indicated that the content of NaCl in inorganic by-products reached 96 %. Increasing initial pH value of CMC wastewater might significantly raise the purity of ethoxyacetic acid in organic by-products. UASB-contact oxidation process showed a good resistance to shock loading. Results of 45-day continuous operation revealed that CODCr of final effluent might be controlled below 500 mg l−1 and meet Shanghai Industrial Wastewater Discharge Standard (CODCr −1, which indicated that the treatment process in this study was appropriate to treat distillate of wastewater from CMC production industry.

  19. Lattice parameters guide superconductivity in iron-arsenides

    International Nuclear Information System (INIS)

    Konzen, Lance M N; Sefat, Athena S

    2017-01-01

    The discovery of superconducting materials has led to their use in technological marvels such as magnetic-field sensors in MRI machines, powerful research magnets, short transmission cables, and high-speed trains. Despite such applications, the uses of superconductors are not widespread because they function much below room-temperature, hence the costly cooling. Since the discovery of Cu- and Fe-based high-temperature superconductors (HTS), much intense effort has tried to explain and understand the superconducting phenomenon. While no exact explanations are given, several trends are reported in relation to the materials basis in magnetism and spin excitations. In fact, most HTS have antiferromagnetic undoped ‘parent’ materials that undergo a superconducting transition upon small chemical substitutions in them. As it is currently unclear which ‘dopants’ can favor superconductivity, this manuscript investigates crystal structure changes upon chemical substitutions, to find clues in lattice parameters for the superconducting occurrence. We review the chemical substitution effects on the crystal lattice of iron-arsenide-based crystals (2008 to present). We note that (a) HTS compounds have nearly tetragonal structures with a -lattice parameter close to 4 Å, and (b) superconductivity can depend strongly on the c -lattice parameter changes with chemical substitution. For example, a decrease in c -lattice parameter is required to induce ‘in-plane’ superconductivity. The review of lattice parameter trends in iron-arsenides presented here should guide synthesis of new materials and provoke theoretical input, giving clues for HTS. (topical review)

  20. Machine learning of molecular electronic properties in chemical compound space

    International Nuclear Information System (INIS)

    Montavon, Grégoire; Müller, Klaus-Robert; Rupp, Matthias; Gobre, Vivekanand; Hansen, Katja; Tkatchenko, Alexandre; Vazquez-Mayagoitia, Alvaro; Anatole von Lilienfeld, O

    2013-01-01

    The combination of modern scientific computing with electronic structure theory can lead to an unprecedented amount of data amenable to intelligent data analysis for the identification of meaningful, novel and predictive structure–property relationships. Such relationships enable high-throughput screening for relevant properties in an exponentially growing pool of virtual compounds that are synthetically accessible. Here, we present a machine learning model, trained on a database of ab initio calculation results for thousands of organic molecules, that simultaneously predicts multiple electronic ground- and excited-state properties. The properties include atomization energy, polarizability, frontier orbital eigenvalues, ionization potential, electron affinity and excitation energies. The machine learning model is based on a deep multi-task artificial neural network, exploiting the underlying correlations between various molecular properties. The input is identical to ab initio methods, i.e. nuclear charges and Cartesian coordinates of all atoms. For small organic molecules, the accuracy of such a ‘quantum machine’ is similar, and sometimes superior, to modern quantum-chemical methods—at negligible computational cost. (paper)

  1. Rapid thermal metalorganic chemical vapor deposition of II VI compounds

    Science.gov (United States)

    Stolyarova, S.; Amir, N.; Nemirovsky, Y.

    1998-02-01

    In this paper we analyze the potential benefits of rapid thermal processing combined with metalorganic chemical vapor deposition (RT-MOCVD) for II-VI compounds and review our first results of the application of RT-MOCVD to the growth of CdTe/CdZnTe, CdTe/HgCdTe and ZnTe/CdTe heterostructures. The RT-MOCVD growth of (1 1 1) CdTe and ZnTe was performed in the A.G. Associates Heatpulse CVD-800™ system using a horizontal quartz reactor heated from both sides by tungsten-halogen lamps. The main features of RT-MOCVD of II-VI materials are: very high growth rates (up to 60 μm/h for CdTe and 30 μm/h for ZnTe); low point defect densities in the epilayers; more abrupt interfaces and less substrate surface degradation compared to conventional MOCVD. Potential of RT-MOCVD for MCT passivation has been shown.

  2. Structure and superconductivity of room temperature chemically oxidized La2-xNdxCuO4+y (0<=x<=0.5)

    DEFF Research Database (Denmark)

    Rial, C.; Moran, E.; Alario-Franco, M.A.

    1997-01-01

    of oxygen introduced in the semiconducting starting materials relieves partially the distortion of the structure, which increases for increasing Nd content, and provides the hole doping required for superconductivity. The extra oxygen content decreases along this series of compounds as the Nd...

  3. Chemical shift of U L3 edges in different uranium compounds ...

    Indian Academy of Sciences (India)

    Administrator

    the chemical environment of the metal ion. The change in absorption edge which could be attributed to different chemical environment of a metal ion inside a compound is generally known as the chemical shift. In the present study, the effect of chemical environ- ment on shifting of L3 X-ray absorption edge of uranium.

  4. Simplified fate modelling in respect to ecotoxicological and human toxicological characterisation of emissions of chemical compounds

    NARCIS (Netherlands)

    Birkved, Morten; Heijungs, Reinout

    Purpose: The impact assessment of chemical compounds in Life Cycle Impact Assessment (LCIA) and Environmental Risk Assessment (ERA) requires a vast amount of data on the properties of the chemical compounds being assessed. The purpose of the present study is to explore statistical options for

  5. On the structural properties and superconductivity of room-temperature chemically oxidized La2-xBaxCuO4+y (0<=x<=0.15)

    DEFF Research Database (Denmark)

    Rial, C.; Moran, E.; Alario-Franco, M.A.

    1996-01-01

    The insertion of oxygen within the structure of La2-xBaxCuO4+y (x less than or equal to 0.15), by means of room-temperature chemical oxidation, modifies both the physical and the structural features of these materials, Concerning the superconducting properties, the extra oxygen gives rise...

  6. Effects of extra oxygen on the structure and superconductivity of La2-xCaxCuO4+y prepared by chemical oxidation

    DEFF Research Database (Denmark)

    Rial, C.; Moran, E.; Alario Franco, M.A.

    1998-01-01

    The insertion of an excess of oxygen within the structure of La2-xCaxCuO4 (x less than or equal to 0.12) by means of room temperature chemical oxidation modifies the physical properties and the crystal structure of these cuprates. The superconducting features of the starting La2-xCaxCuO4 samples...

  7. Chemical reactivity of hypervalent silicon compounds: The local ...

    Indian Academy of Sciences (India)

    Unknown

    Nacional de Ciencia y Tecnología, CONACYT-. México. References. 1. Selected reviews dealing with pentacoordinate silicon compounds: (a) Tandura S N, Voronkov M G and. Alekseev N V 1986 Top. Curr. Chem. 131 99; (b). Corriu R J P and Young J C 1989. In The chemistry of organic silicon compounds (eds) S Patai ...

  8. Absence of low energy magnetic spin-fluctuations in isovalently and aliovalently doped LaCo2B2 superconducting compounds

    Science.gov (United States)

    Majumder, M.; Ghoshray, A.; Khuntia, P.; Mazumdar, C.; Poddar, A.; Baenitz, M.; Ghoshray, K.

    2016-09-01

    Magnetization, resistivity and 11B, 59Co NMR measurements have been performed on the Pauli paramagnet \\text{LaC}{{\\text{o}}2}{{\\text{B}}2} , and the superconductors \\text{L}{{\\text{a}}0.9}{{\\text{Y}}0.1}\\text{C}{{\\text{o}}2}{{\\text{B}}2} ({{T}\\text{c}}≈ 4.2 K) and \\text{La}{{≤ft(\\text{C}{{\\text{o}}0.7}\\text{F}{{\\text{e}}0.3}\\right)}2}{{\\text{B}}2} ({{T}\\text{c}}≈ 5.8 K). The site selective NMR experiment reveals the multiband nature of the Fermi surface in these systems. The temperature independent Knight shift and 1/T 1 T clearly indicate the absence of correlated low energy magnetic spin-fluctuations in the normal state, which is in contrast to other Fe-based pnictides. The density of states (DOS) of Co 3d electrons has been enhanced in superconducting \\text{L}{{\\text{a}}0.9}{{\\text{Y}}0.1}\\text{C}{{\\text{o}}2}{{\\text{B}}2} and \\text{La}{{≤ft(\\text{C}{{\\text{o}}0.7}\\text{F}{{\\text{e}}0.3}\\right)}2}{{\\text{B}}2} with respect to the non superconducting reference compound \\text{LaC}{{\\text{o}}2}{{\\text{B}}2} . The occurrence of superconductivity is related to the DOS enhancement.

  9. Superconductivity, structures, ESR and SIMS-analysis of a high-Tc Y0.33Ba0.67Cu2.33O3.67-σ compound

    International Nuclear Information System (INIS)

    Porjesz, T.; Bankuti, J.; Karman, T.

    1987-10-01

    In a new kind of high-T c Y 0.33 Ba 0.67 Cu 2.33 O 3.67-σ compound the superconducting transition comes into being between 92 and 84 K, the value of Meissner state is 68 vol.%, the change in ESR signal provides a possible proof for superconductivity, the main phase has an orthorhombic symmetry and the SIMS analysis offers quite new and valuable information on the material components. (author). 10 refs, 6 figs

  10. Metal organic chemical vapor deposition of superconducting YBa2Cu3O7-x thin films

    Science.gov (United States)

    Zawadzki, P. A.; Tompa, G. S.; Norris, P. E.; Chern, C. S.; Caracciolo, R.; Kear, B. H.; Noh, D. W.; Gallois, B.

    1990-04-01

    The discovery of YBCO superconductors has stimulated a great deal of scientific and technological research into thin films of these materials. Because the MOCVD technique is known to produce high quality films in the III/V and II/VI material groups, our approach has been to apply the method to superconducting thin films. Thin films were grown in a vertical high speed (0 2000 rpm) rotating disk reactor. The source materials were metal β-diketonates kept at temperatures in excess of 100° in order to obtain growth rates of 0.3 to 0.5 μm/hr. The precursors were transported to the chamber with a nitrogen carrier and injected separately in order to avoid any gas phase reactions. The chamber pressure was maintained at 76 Torr with an oxygen partial pressure of 38 Torr. A resistance heater was used to keep the substrate temperature at 500° YBa2Cu3O7- x films were deposited simultaneously on a variety of substrates such as (100) MgO, (1-102) sapphire, (100) SrTiO3 and (100) YSZ. Full XPS spectra were collected for the binary oxides. The scans demonstrate the existence of Y2O3, BaO, and CuO with the correct valence state for the metallic species. Energy dispersive analysis of x-ray (EDAX) was used to determine film compositions by comparing EDAX spectral intensity to a known superconducting standard. Appropriate changes were made in the precursor flows to correct the stoichiometry. The as-grown films were dark brown and semi-transparent. Cross-sectional SEM photomicrographs revealed an ordered columnar structure. After annealing at 950 980° however, the films on (100) SrTiO3 appeared dull black and opaque. The surface morphology exhibited smooth large plate-like grains. X-ray data clearly display an orthorhombic phase, with c-axis perpendicular to the substrate surface. Four point resistance measurements for films on (100) SrTiO3 show the onset of superconductivity at 90 K with a complete loss of resistance at 88 K. This sharp (≤2K) transition shows the high quality

  11. Microscopic physical and chemical properties of graphite intercalation compounds

    Energy Technology Data Exchange (ETDEWEB)

    Eklund, P.C.

    1992-08-24

    Optical spectroscopy (Raman, FTIR and Reflection ) was used to study a variety of acceptor- and donor-type compounds synthesized to determine the microscopic models consistent with the spectrocsopic results. General finding is that the electrical conduction properties of these compounds can be understood on the basis that the intercalation of atomic and/or molecular species between the host graphite layers either raises or lowers the Fermi level (E{sub F)} in a graphitic band structure. This movement of E{sub F} is accomplished via a charge transfer of electrons from the intercalate layers to the graphitic layers (donor compounds), or vice versa (acceptor compounds). Furthermore, the band structure must be modified to take into account the layers of charge that occur as a result of the charge transfer. This charge layering introduces additional bands of states near E{sub F}, which are discussed. Charge-transfer also induces a perturbation of the graphitic normal mode frequencies which can be understood as the result of a contraction (acceptor compounds) or expansion (donor compounds) of the intralayer C-C bonds. Ab-initio calculations support this view and are in reasonable agreement with experimental data.

  12. A pinning puzzle: two similar, non-superconducting chemical deposits in YBCO-one pins, the other does not

    Energy Technology Data Exchange (ETDEWEB)

    Sawh, Ravi-Persad; Weinstein, Roy; Gandini, Alberto; Skorpenske, Harley; Parks, Drew, E-mail: Weinstein@uh.ed [Beam Particle Dynamics Laboratories, University of Houston, Houston, TX 77204-5005 (United States); Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Texas Center for Superconductivity at UH, University of Houston, Houston, TX 77204-5002 (United States)

    2009-09-15

    The pinning effects of two kinds of U-rich deposits in YBCO (YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}) are compared. One is a five-element compound, (U{sub 0.6}Pt{sub 0.4})YBa{sub 2}O{sub 6}, which is a paramagnetic double perovskite which forms as profuse stable nanosize deposits, and pins very well. The other is a four-element compound, (U{sub 0.4}Y{sub 0.6})BaO{sub 3}, which is a ferromagnetic single perovskite which forms as profuse stable nanosize deposits and pins very weakly or not at all. The pinning comparison is done with nearly equal deposit sizes and number of deposits per unit volume for the two compounds. Evidence for the pinning capability, chemical makeup, x-ray diffraction signature, and magnetic properties of the two compounds is reported.

  13. Applied superconductivity

    CERN Document Server

    Newhouse, Vernon L

    1975-01-01

    Applied Superconductivity, Volume II, is part of a two-volume series on applied superconductivity. The first volume dealt with electronic applications and radiation detection, and contains a chapter on liquid helium refrigeration. The present volume discusses magnets, electromechanical applications, accelerators, and microwave and rf devices. The book opens with a chapter on high-field superconducting magnets, covering applications and magnet design. Subsequent chapters discuss superconductive machinery such as superconductive bearings and motors; rf superconducting devices; and future prospec

  14. Superconducting state mechanisms and properties

    CERN Document Server

    Kresin, Vladimir Z; Wolf, Stuart A

    2014-01-01

    'Superconducting State' provides a very detailed theoretical treatment of the key mechanisms of superconductivity, including the current state of the art (phonons, magnons, and plasmons). A very complete description is given of the electron-phonon mechanism responsible for superconductivity in the majority of superconducting systems, and the history of its development, as well as a detailed description of the key experimental techniques used to study the superconducting state and determine the mechanisms. In addition, there are chapters describing the discovery and properties of the key superconducting compounds that are of the most interest for science, and applications including a special chapter on the cuprate superconductors. It provides detailed treatments of some very novel aspects of superconductivity, including multiple bands (gaps), the "pseudogap" state, novel isotope effects beyond BCS, and induced superconductivity.

  15. the tj model and superconductivity

    African Journals Online (AJOL)

    DJFLEX

    Perhaps that in the reason why their explanations of the superconductivity have had limited scope . A proper theory and mechanism of superconductivity in the ceramic cuprates should take account of magnetism inherent in the compounds. For the (214) compound experiment have revealed strong antiferromagnetic (AF).

  16. Determination of borneol and other chemical compounds of ...

    African Journals Online (AJOL)

    Results: Essential oil (7.58 %) was obtained with the highest yield (3.24 %) in the first 2 h of fractional distillation. Thirty compounds which accounted for ... Commonwealth Forest Reserve, Selangor,. Malaysia. Plant identification was ... system was operated in scan mode with a mass range of 50 – 800 m/z. Identification of.

  17. Chemical evaluation of protein quality and phenolic compound ...

    African Journals Online (AJOL)

    Dr ACHU Mercy BIH epouse LOH

    2011-07-07

    Jul 7, 2011 ... These results show a great variability on the protein contents which depend on the specie and which also seem to depend on the regions, as seen from the low values obtained for Sudanese seeds. Phenolic compounds have been shown to have a lot of beneficial effects as antioxidants, antithrombotic and ...

  18. Inelastic neutron scattering study of a nonmagnetic collapsed tetragonal phase in nonsuperconducting CaFe2As2: evidence of the impact of spin fluctuations on superconductivity in the iron-arsenide compounds.

    Science.gov (United States)

    Soh, J H; Tucker, G S; Pratt, D K; Abernathy, D L; Stone, M B; Ran, S; Bud'ko, S L; Canfield, P C; Kreyssig, A; McQueeney, R J; Goldman, A I

    2013-11-27

    The relationship between antiferromagnetic spin fluctuations and superconductivity has become a central topic of research in studies of superconductivity in the iron pnictides. We present unambiguous evidence of the absence of magnetic fluctuations in the nonsuperconducting collapsed tetragonal phase of CaFe2As2 via inelastic neutron scattering time-of-flight data, which is consistent with the view that spin fluctuations are a necessary ingredient for unconventional superconductivity in the iron pnictides. We demonstrate that the collapsed tetragonal phase of CaFe2As2 is nonmagnetic, and discuss this result in light of recent reports of high-temperature superconductivity in the collapsed tetragonal phase of closely related compounds.

  19. Cyanobacterium sp. host cell and vector for production of chemical compounds in Cyanobacterial cultures

    Energy Technology Data Exchange (ETDEWEB)

    Piven, Irina; Friedrich, Alexandra; Duhring, Ulf; Uliczka, Frank; Baier, Kerstin; Inaba, Masami; Shi, Tuo; Wang, Kui; Enke, Heike; Kramer, Dan

    2016-04-19

    A cyanobacterial host cell, Cyanobacterium sp., that harbors at least one recombinant gene for the production of a chemical compounds is provided, as well as vectors derived from an endogenous plasmid isolated from the cell.

  20. Evidence for Different Reactive Hg Sources and Chemical Compounds at Adjacent Valley and High Elevation Locations.

    Science.gov (United States)

    Sexauer Gustin, Mae; Pierce, Ashley M; Huang, Jiaoyan; Miller, Matthieu B; Holmes, Heather A; Loria-Salazar, S Marcela

    2016-11-15

    The spatial distribution of chemical compounds and concentration of reactive mercury (RM), defined as the sum of gaseous oxidized mercury (GOM) and atmospheric models, which in turn influence policy decisions.

  1. Atomic Charges and Chemical Bonding in Y-Ga Compounds

    Directory of Open Access Journals (Sweden)

    Yuri Grin

    2018-02-01

    Full Text Available A negative deviation from Vegard rule for the average atomic volume versus yttrium content was found from experimental crystallographic information about the binary compounds of yttrium with gallium. Analysis of the electron density (DFT calculations employing the quantum theory of atoms in molecules revealed an increase in the atomic volumes of both Y and Ga with the increase in yttrium content. The non-linear increase is caused by the strengthening of covalent Y-Ga interactions with stronger participation of genuine penultimate shell electrons (4d electrons of yttrium in the valence region. Summing the calculated individual atomic volumes for a unit cell allows understanding of the experimental trend. With increasing yttrium content, the polarity of the Y-Ga bonding and, thus its ionicity, rises. The covalency of the atomic interactions in Y-Ga compounds is consistent with their delocalization from two-center to multi-center ones.

  2. Grape Seed Oil Compounds: Biological and Chemical Actions for Health.

    Science.gov (United States)

    Garavaglia, Juliano; Markoski, Melissa M; Oliveira, Aline; Marcadenti, Aline

    2016-01-01

    Grape seed oil is rich in phenolic compounds, fatty acids, and vitamins, with economic importance to pharmaceutical, cosmetic, and food industry. Its use as an edible oil has also been suggested, especially due to its pleasant sensory characteristics. Grape seed oil has beneficial properties for health that are mainly detected by in vitro studies, such as anti-inflammatory, cardioprotective, antimicrobial, and anticancer properties, and may interact with cellular and molecular pathways. These effects have been related to grape seed oil constituents, mainly tocopherol, linolenic acid, resveratrol, quercetin, procyanidins, carotenoids, and phytosterols. The aim of this article was to briefly review the composition and nutritional aspects of grape seed oil, the interactions of its compounds with molecular and cellular pathways, and its possible beneficial effects on health.

  3. Grape Seed Oil Compounds: Biological and Chemical Actions for Health

    Directory of Open Access Journals (Sweden)

    Juliano Garavaglia

    2016-01-01

    Full Text Available Grape seed oil is rich in phenolic compounds, fatty acids, and vitamins, with economic importance to pharmaceutical, cosmetic, and food industry. Its use as an edible oil has also been suggested, especially due to its pleasant sensory characteristics. Grape seed oil has beneficial properties for health that are mainly detected by in vitro studies, such as anti-inflammatory, cardioprotective, antimicrobial, and anticancer properties, and may interact with cellular and molecular pathways. These effects have been related to grape seed oil constituents, mainly tocopherol, linolenic acid, resveratrol, quercetin, procyanidins, carotenoids, and phytosterols. The aim of this article was to briefly review the composition and nutritional aspects of grape seed oil, the interactions of its compounds with molecular and cellular pathways, and its possible beneficial effects on health.

  4. Propolis volatile compounds: chemical diversity and biological activity: a review

    OpenAIRE

    Bankova, Vassya; Popova, Milena; Trusheva, Boryana

    2014-01-01

    Propolis is a sticky material collected by bees from plants, and used in the hive as building material and defensive substance. It has been popular as a remedy in Europe since ancient times. Nowadays, propolis use in over-the-counter preparations, “bio”-cosmetics and functional foods, etc., increases. Volatile compounds are found in low concentrations in propolis, but their aroma and significant biological activity make them important for propolis characterisation. Propolis is a plant-derived...

  5. Radiation induced chemical changes of phenolic compounds in strawberries

    Energy Technology Data Exchange (ETDEWEB)

    Breitfellner, F.; Solar, S. E-mail: sonja.solar@univie.ac.at; Sontag, G

    2003-06-01

    In unirradiated strawberries four phenolic acids (gallic acid, p-coumaric acid, caffeic acid and 4-hydroxybenzoic acid), the flavonoids (+)-catechin, (-)-epicatechin and glycosides from kaempferol and quercetin were determined by reversed phase chromatography with diode array detection. Characteristic linear dose/concentration relationships were found for 4-hydroxybenzoic acid and two unidentified compounds. One of them may be usable as marker to prove an irradiation treatment.

  6. Radiation induced chemical changes of phenolic compounds in strawberries

    International Nuclear Information System (INIS)

    Breitfellner, F.; Solar, S.; Sontag, G.

    2002-01-01

    Complete text of publication follows. The investigations were directed to the determination of the effect of γ-irradiation on various phenolic compounds in strawberries in dependence of dose. A significant decrease of these compounds during irradiation could reduce their beneficial effect on health, which are based on their antioxidative and anticarcinogenic properties. On the other hand hydroxilation of phenolic acids has been proposed as a promising method to distinguish between irradiated and not irradiated fruits and vegetables. Irradiated and not irradiated strawberry samples were homogenized, centrifuged and chromatographically purified from matrix components on polyamide columns. For determination of hydroxybenzoic and hydroxycinnamic acids, which are present as esters or as glycosides, the samples had to be acid/base hydrolized prior to purification. The individual compounds were separated by reversed phase chromatography and detected by means of a diode-array-detector. Peak identification was based on both UV-Vis-spectra and retention times compared with those of standards. In hydrolized samples four phenolic acids [gallic acid, 4-hydroxybenzoic acid, p-coumaric acid and caffeic acid] were identified. Only 4-hydroxybenzoic acid was affected by irradiation (build up with dose). Five flavonoids were detected in non hydrolized samples [(+)-catechin, (-)-epicatechin, kaempferol-3-glucoside, quercetin-3-glucoside and, in trace quantities, quercetin-3-galactoside], the concentration of the catechines and of kaempferol-3-glucoside decreased as irradiation dose increased, whereas those of quercetin-3-glucoside remained unchanged. In addition two as yet unclassified compounds showed a significant change of concentration upon irradiation. One of them (m/e = 450) is decreasing, one (m/e = 318) is increasing to the fivefold at a dose of 6 kGy

  7. Radiation induced chemical changes of phenolic compounds in strawberries

    International Nuclear Information System (INIS)

    Breitfellner, F.; Solar, S.; Sontag, G.

    2003-01-01

    In unirradiated strawberries four phenolic acids (gallic acid, p-coumaric acid, caffeic acid and 4-hydroxybenzoic acid), the flavonoids (+)-catechin, (-)-epicatechin and glycosides from kaempferol and quercetin were determined by reversed phase chromatography with diode array detection. Characteristic linear dose/concentration relationships were found for 4-hydroxybenzoic acid and two unidentified compounds. One of them may be usable as marker to prove an irradiation treatment

  8. Grape Seed Oil Compounds: Biological and Chemical Actions for Health

    OpenAIRE

    Juliano Garavaglia; Melissa M. Markoski; Aline Oliveira; Aline Marcadenti

    2016-01-01

    Grape seed oil is rich in phenolic compounds, fatty acids, and vitamins, with economic importance to pharmaceutical, cosmetic, and food industry. Its use as an edible oil has also been suggested, especially due to its pleasant sensory characteristics. Grape seed oil has beneficial properties for health that are mainly detected by in vitro studies, such as anti-inflammatory, cardioprotective, antimicrobial, and anticancer properties, and may interact with cellular and molecular pathways. These...

  9. the implications of agro-chemical compounds (fertilizers, pesticides

    African Journals Online (AJOL)

    User

    2015-12-02

    Dec 2, 2015 ... extensive agriculture by the lakes riparian states is reducing the water and stressing the ecological balance affecting the organisms depending on ... impact of the use of fertilizers and agro-chemicals on the quality of the Lake Chad water. ... All plastics and glass wares were pre-washed with detergent water ...

  10. Hen eggs chemical compounds, caloricity and cholesterol level, as ...

    African Journals Online (AJOL)

    simba

    2014-02-08

    Feb 8, 2014 ... Keywords: Battery cages, chemical composition, dietetic value, improved cages, free-range, laying hens. # Corresponding author: umariusg@gmail.com ... complemented with vitamin E as an antioxidant (Sparks, 2006), through a dietary combination of fish and linseed oils (King et al., 2012), or through diet ...

  11. Bibliography of physical and chemical properties of plutonium and of some of its compounds

    International Nuclear Information System (INIS)

    Lefevre, J.

    1957-02-01

    This document proposes two lists of bibliographical references which respectively concern the physical properties of metallic plutonium and intermetallic plutonium compounds (addressed topics in these documents are state diagrams, crystal structure, and so on), and the chemical properties of plutonium and of some of its compounds (addressed topics are heavy elements, transuranium elements, and so on)

  12. Chemical effects of alkali atoms on critical temperature in superconducting alkali-doped fullerides

    Science.gov (United States)

    Hetfleisch, F.; Gunnarsson, O.; Srama, R.; Han, J. E.; Stepper, M.; Roeser, H.-P.; Bohr, A.; Lopez, J. S.; Mashmool, M.; Roth, S.

    2018-03-01

    Alkali metal doped fullerides (A3C60) are superconductors with critical temperatures, Tc, extending up to 38 K. Tc is known to depend strongly on the lattice parameter a, which can be adjusted by physical or chemical pressure. In the latter case an alkali atom is replaced by a different sized one, which changes a. We have collected an extensive data base of experimental data for Tc from very early up to recent measurements. We disentangle alkali atom chemical effects on Tc, beyond the well-known consequences of changing a. It is found that Tc, for a fixed a, is typically increased as smaller alkali atoms are replaced by larger ones, except for very large a. Possible reasons for these results are discussed. Although smaller in size than the lattice parameter contribution, the chemical effect is not negligible and should be considered in future physical model developments.

  13. Chemical Compounds Recovery in Carboxymethyl Cellulose Wastewater Treatment

    OpenAIRE

    P.-H. Rao; W.-Q. Zhang; W. Yao; A.-Y. Zhu; J.-L. Xia; Y.-F. Tan; T.-Z. Liu

    2015-01-01

    Carboxymethyl cellulose (CMC) is a kind of cellulose ether widely used in industrial production. CMC wastewater usually have high chemical oxygen demand (COD) and salinity (>10 %), which result from organic and inorganic by-products during CMC production. It is significant that the wastewater is pretreated to decrease salinity and recover valuable organics before biochemical methods are employed. In this paper, distillation-extraction method was used to pretreat CMC wastewater and recover val...

  14. Academic training: Applied superconductivity

    CERN Multimedia

    2007-01-01

    LECTURE SERIES 17, 18, 19 January from 11.00 to 12.00 hrs Council Room, Bldg 503 Applied Superconductivity : Theory, superconducting Materials and applications E. PALMIERI/INFN, Padova, Italy When hearing about persistent currents recirculating for several years in a superconducting loop without any appreciable decay, one realizes that we are dealing with a phenomenon which in nature is the closest known to the perpetual motion. Zero resistivity and perfect diamagnetism in Mercury at 4.2 K, the breakthrough during 75 years of several hundreds of superconducting materials, the revolution of the "liquid Nitrogen superconductivity"; the discovery of still a binary compound becoming superconducting at 40 K and the subsequent re-exploration of the already known superconducting materials: Nature discloses drop by drop its intimate secrets and nobody can exclude that the last final surprise must still come. After an overview of phenomenology and basic theory of superconductivity, the lectures for this a...

  15. Chemical Compound Navigator: A Web-Based Chem-BLAST, Chemical Taxonomy-Based Search Engine for Browsing Compounds

    Czech Academy of Sciences Publication Activity Database

    Prasanna, M. D.; Vondrášek, Jiří; Wlodawer, A.; Rodriguez, H.; Bhat, T. N.

    2006-01-01

    Roč. 63, č. 4 (2006), s. 907-917 ISSN 0887-3585 Institutional research plan: CEZ:AV0Z40550506 Keywords : HIV * AIDS * drug discovery * chemical data-tree Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.730, year: 2006

  16. Simplified fate modelling in respect to ecotoxicological and human toxicological characterisation of emissions of chemical compounds

    DEFF Research Database (Denmark)

    Birkved, Morten; Heijungs, Reinout

    2011-01-01

    The impact assessment of chemical compounds in Life Cycle Impact Assessment (LCIA) and Environmental Risk Assessment (ERA) requires a vast amount of data on the properties of the chemical compounds being assessed. The purpose of the present study is to explore statistical options for reduction...... the independent chemical input parameters from the minimum data set, needed for characterisation in USEtox™, according to general availability, importance and relevance for fate factor prediction.Each approach (63% and 75% of the minimum data set needed for characterisation in USEtox™) yielded 66 meta...

  17. Interplay of magnetism and superconductivity in the compressed Fe-ladder compound BaFe2Se3

    Energy Technology Data Exchange (ETDEWEB)

    Ying, Jianjun; Lei, Hechang; Petrovic, Cedomir; Xiao, Yuming; Struzhkin, Viktor V. (BNL); (CIW)

    2017-06-01

    High pressure resistance, susceptibility, and Fe K β x-ray emission spectroscopy measurements were performed on Fe-ladder compound BaFe 2 Se 3 . Pressure-induced superconductivity was observed which is similar to the previously reported superconductivity in the BaFe 2 S 3 samples. The slope of local magnetic moment versus pressure shows an anomaly across the insulator-metal transition pressure in the BaFe 2 Se 3 samples. The local magnetic moment is continuously decreasing with increasing pressure, and the superconductivity appears only when the local magnetic moment value is comparable to the one in the iron-pnictide superconductors. Our results indicate that the compressed BaFe 2 C h 3 ( C h = S , Se) is a new family of iron-based superconductors. Despite the crystal structures completely different from the known iron-based superconducting materials, the magnetism in this Fe-ladder material plays a critical role in superconductivity. This behavior is similar to the other members of iron-based superconducting materials.

  18. Action of certain chemical compounds on radiation haemolysis of erythrocytes

    International Nuclear Information System (INIS)

    Kolesnikov, Yu.A.; Shulgina, M.A.; Yartsev, E.I.; Novoseltseva, S.D.; Bogatyrev, G.P.

    1975-01-01

    A radioprotective action of a number of protective chemicals on radiation haemolysis of erythrocytes has been studied. S-bearing radioprotectors, serotonin and arginine possess the highest radioprotective activity. The same radioprotectors delivered to the medium after irradiation do not influence the development of the post-irradiation haemolysis. Certain amino acids, namely proline, serine and taurine have a pronounced radio-protective action when given to the medium after irradiation, taurine producing the strongest effect on the development of radiation haemolysis. The mechanism of action of these substances is unrelated to the increased osmotic pressure of the medium and might be explained by normalization of the functional state of cytomembranes and processes of cell metabolism

  19. Chemical quality parameters and bioactive compound content of brazilian berries

    Directory of Open Access Journals (Sweden)

    Daniela Mota Segantini

    2015-09-01

    Full Text Available There is a growing consumer demand for higher healthy foods such as berries which are a rich source of phenolic compounds. The current work evaluated blackberry cultivars: Cherokee, Tupy and Xavante; raspberry cultivars: Heritage, Fallgold and Black; and the hybrid Boysenberry. All berries were grown under homogenous subtropical conditions in Brazil. Black raspberry, Cherokee and Tupy blackberry cultivars showed the highest ratio between soluble solid contents and titratable acidity, and Fallgold and Heritage raspberry showed the highest titratable acidity. Total phenolic content ranged from 2.03 to 5.33 g kg–1 fresh weight and total anthocyanin content registered values from 0.41 to 1.81 g kg–1 fresh weight. The most common phenolic acids were gallic, p-coumaric and ellagic, and for anthocyanins: cyanidin-3-glucoside and malvinidin-3-glucoside. Antioxidant capacity ranged from 14.13 to 21.51 mol equivalent trolox kg–1 fresh weight. Black raspberry, all blackberry cultivars and the Boysenberry hybrid are appropriate to be consumed fresh, while Fallgold and Heritage raspberries are recommended to the food industry. Due to their phenolic richness and antioxidant properties, these fruits are of great interest to the fresh fruit market and to pharmaceutical industries. These results could help breeders and growers when planning the cultivar selection according to their foreseeable destination.

  20. Interface high-temperature superconductivity

    Science.gov (United States)

    Wang, Lili; Ma, Xucun; Xue, Qi-Kun

    2016-12-01

    Cuprate high-temperature superconductors consist of two quasi-two-dimensional (2D) substructures: CuO2 superconducting layers and charge reservoir layers. The superconductivity is realized by charge transfer from the charge reservoir layers into the superconducting layers without chemical dopants and defects being introduced into the latter, similar to modulation-doping in the semiconductor superlattices of AlGaAs/GaAs. Inspired by this scheme, we have been searching for high-temperature superconductivity in ultra-thin films of superconductors epitaxially grown on semiconductor/oxide substrates since 2008. We have observed interface-enhanced superconductivity in both conventional and unconventional superconducting films, including single atomic layer films of Pb and In on Si substrates and single unit cell (UC) films of FeSe on SrTiO3 (STO) substrates. The discovery of high-temperature superconductivity with a superconducting gap of ∼20 meV in 1UC-FeSe/STO has stimulated tremendous interest in the superconductivity community, for it opens a new avenue for both raising superconducting transition temperature and understanding the pairing mechanism of unconventional high-temperature superconductivity. Here, we review mainly the experimental progress on interface-enhanced superconductivity in the three systems mentioned above with emphasis on 1UC-FeSe/STO, studied by scanning tunneling microscopy/spectroscopy, angle-resolved photoemission spectroscopy and transport experiments. We discuss the roles of interfaces and a possible pairing mechanism inferred from these studies.

  1. Silica gel surface as chemical reagent in radiation chemical transformations of adsorbed compounds

    International Nuclear Information System (INIS)

    Laskorin, B.N.; Strelko, V.V.; Strazhesko, D.N.; Denisov, V.I.

    1977-01-01

    Studied is the mechanism of the ionizing radiation effect on the heterogeneous systems, containing dispersed silica gels as one of the components. Radiation-chemical transformations of substances adsorbed by silica gels (radiolysis and radiation- chemical synthesis) are characterized by increased yields and by sufficient change of reaction selectivity in comparison with homogeneous medium. It is shown that in silica gel case, surface may also participate in radiolysis and in radiation-chemical synthesis as a chemical agent, generating hot hydrogen atoms and active surface SiO- and Si- radicals into the reaction zone under radiation. The data obtained are analyzed from the point of view of peculiarities of the building of i-O bonds and also of the chemical properties of the silica gel surface. It testifies that silica gel sorbents may be viewed as peculiar effective chemical agents in radiation- chemical reactions of adsorbed substances

  2. Bioautography and chemical characterization of antimicrobial compound(s) in commercial water-soluble annatto extracts.

    Science.gov (United States)

    Galindo-Cuspinera, Veronica; Rankin, Scott A

    2005-04-06

    Annatto preparations based on extracts of the seed of tropical bush Bixa orellana L consist of carotenoid-type pigments. Previous reports indicate that commercial annatto extracts have biological activities against microorganisms of significance to food fermentation, preservation, and safety. The objective of this study was to separate and identify the compound(s) responsible for the antimicrobial activity of annatto preparations. Commercial water-soluble annatto extracts were screened by thin-layer chromatography and bioautography followed by liquid chromatography/photodiode array/mass spectrometry (LC/PDA/MS) analysis of active fractions. Bioautography revealed two fractions with antimicrobial activity against Staphylococcus aureus. LC/PDA/MS analysis of both fractions revealed 9'-cis-norbixin (UV(max) 460 and 489 nm) and all-trans-norbixin (UV(max) 287, 470, and 494 nm) as the major components. Structure confirmation was achieved by (1)H NMR spectroscopy. Results indicate that 9'-cis-norbixin and all-trans-norbixin are responsible for the antimicrobial properties of annatto.

  3. In situ growth of YBa2Cu3O7 - x high Tc superconducting thin films directly on sapphire by plasma-enhanced metalorganic chemical vapor deposition

    Science.gov (United States)

    Chern, C. S.; Zhao, J.; Li, Y. Q.; Norris, P.; Kear, B.; Gallois, B.

    1990-08-01

    Highly c-axis oriented YBa2Cu3O7-x superconducting thin films have been, in situ, deposited directly on sapphire substrate by a remote microwave plasma-enhanced metalorganic chemical vapor deposition process (PE-MOCVD). The films were deposited at a substrate temperature of 730 °C followed by a fast cooling. The as-deposited films show attainment of zero resistance at 82 K and have critical current density of 104 A/cm2 at 70 K. ac susceptibility measurement indicated that the films contain a single superconducting phase. PE-MOCVD was carried out in a commercial-scale MOCVD reactor with capability of uniform deposition over 100 cm2 per growth run.

  4. Enhanced flux pinning properties in superconducting YBa{sub 2}Cu{sub 3}O{sub 7−z} films by a novel chemical doping approach

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.T., E-mail: wtwang@swjtu.edu.cn [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Pu, M.H.; Lei, M.; Zhang, H.; Wang, Z. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia); Zhao, Y., E-mail: yzhao@swjtu.edu.cn [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Southwest Jiaotong University, Mail Stop 165, Chengdu, Sichuan 610031 (China); Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia)

    2013-10-15

    Highlights: • Pure and Co-doped YBCO films were prepared by newly-developed chemical method. • The doped films have much denser and smoother surface microstructures. • Significantly enhanced fux-pinning properties have been obtained for dilute Co-doped flm. -- Abstract: Pure and cobalt-doped superconducting YBa{sub 2}Cu{sub 3}O{sub 7−z} (YBCO) films were prepared on (0 0 l) LaAlO{sub 3} substrate by a newly developed polymer-assisted metal organic deposition method. The cobalt-doped YBCO films display much denser and smoother surface microstructures and the superconducting transition temperature T{sub c} spans a small range of 1.7 K with the doping levels. Significantly enhanced flux-pinning properties have been obtained for dilute cobalt-doped film. This may be attributed to the good grain connections and the effective flux pinning centers introduced by cobalt doping.

  5. Crystal chemical characterization of mullite-type aluminum borate compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, K., E-mail: Kristin.Hoffmann@uni-bremen.de [Kristallographie, FB05, Klagenfurter Straße / GEO, Universität Bremen, D-28359 Bremen (Germany); Institut für Anorganische Chemie und Kristallographie, FB02, Leobener Straße / NW2, Universität Bremen, D-28359 Bremen (Germany); Hooper, T.J.N. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Zhao, H.; Kolb, U. [Institut für Anorganische Chemie und Analytische Chemie, Jakob-Welder-WegJakob-Welder-Weg 11, Johannes Gutenberg-University Mainz, D-55128 Mainz (Germany); Murshed, M.M. [Institut für Anorganische Chemie und Kristallographie, FB02, Leobener Straße / NW2, Universität Bremen, D-28359 Bremen (Germany); MAPEX Center for Materials and Processes, Bibliothekstraße 1, Universität Bremen, D-28359 Bremen (Germany); Fischer, M.; Lührs, H. [Kristallographie, FB05, Klagenfurter Straße / GEO, Universität Bremen, D-28359 Bremen (Germany); MAPEX Center for Materials and Processes, Bibliothekstraße 1, Universität Bremen, D-28359 Bremen (Germany); Nénert, G. [Institut Laue-Langevin, 6 Rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Kudějová, P.; Senyshyn, A. [Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, D-85748 Garching (Germany); and others

    2017-03-15

    Al-rich aluminum borates were prepared by different synthesis routes using various Al/B ratios, characterized by diffraction methods, spectroscopy and prompt gamma activation analysis. The {sup 11}B NMR data show a small amount of BO{sub 4} species in all samples. The chemical analysis indicates a trend in the Al/B ratio instead of a fixed composition. Both methods indicate a solid solution Al{sub 5−x}B{sub 1+x}O{sub 9} where Al is substituted by B in the range of 1–3%. The structure of B-rich Al{sub 4}B{sub 2}O{sub 9} (C2/m, a=1488 pm, b=553 pm, c=1502 pm, ß=90.6°), was re-investigated by electron diffraction methods, showing that structural details vary within a crystallite. In most of the domains the atoms are orderly distributed, showing no signal for the postulated channel oxygen atom O5. The absence of O5 is supported by density functional theory calculations. Other domains show a probable disordered configuration of O5 and O10, indicated by diffuse scattering along the b direction. - Graphical abstract: Projections of three-dimensional electron diffraction space of Al{sub 4}B{sub 2}O{sub 9} along the main directions. - Highlights: • The crystal structure of Al{sub 4}B{sub 2}O{sub 9} was re-evaluated. • Structural details vary among different crystals and inside Al{sub 4}B{sub 2}O{sub 9} crystallites. • Diffuse scattering indicate a probable disordered configuration of O5 and O10. • A solid solution series for Al{sub 5−x}B{sub x}O{sub 9} is indicated by PGAA and NMR spectroscopy. • The presence of BO{sub 4} groups is confirmed by {sup 11}B MAS NMR spectroscopy for Al{sub 5−x}B{sub 1+x}O{sub 9}.

  6. Exploring sets of molecules from patents and relationships to other active compounds in chemical space networks

    Science.gov (United States)

    Kunimoto, Ryo; Bajorath, Jürgen

    2017-09-01

    Patents from medicinal chemistry represent a rich source of novel compounds and activity data that appear only infrequently in the scientific literature. Moreover, patent information provides a primary focal point for drug discovery. Accordingly, text mining and image extraction approaches have become hot topics in patent analysis and repositories of patent data are being established. In this work, we have generated network representations using alternative similarity measures to systematically compare molecules from patents with other bioactive compounds, visualize similarity relationships, explore the chemical neighbourhood of patent molecules, and identify closely related compounds with different activities. The design of network representations that combine patent molecules and other bioactive compounds and view patent information in the context of current bioactive chemical space aids in the analysis of patents and further extends the use of molecular networks to explore structure-activity relationships.

  7. Ceramic superconductor/metal composite materials employing the superconducting proximity effect

    Science.gov (United States)

    Holcomb, Matthew J.

    2002-01-01

    Superconducting composite materials having particles of superconducting material disposed in a metal matrix material with a high electron-boson coupling coefficient (.lambda.). The superconducting particles can comprise any type of superconductor including Laves phase materials, Chevrel phase materials, A15 compounds, and perovskite cuprate ceramics. The particles preferably have dimensions of about 10-500 nanometers. The particles preferably have dimensions larger than the superconducting coherence length of the superconducting material. The metal matrix material has a .lambda. greater than 0.2, preferably the .lambda. is much higher than 0.2. The metal matrix material is a good proximity superconductor due to its high .lambda.. When cooled, the superconductor particles cause the metal matrix material to become superconducting due to the proximity effect. In cases where the particles and the metal matrix material are chemically incompatible (i.e., reactive in a way that destroys superconductivity), the particles are provided with a thin protective metal coating. The coating is chemically compatible with the particles and metal matrix material. High Temperature Superconducting (HTS) cuprate ceramic particles are reactive and therefore require a coating of a noble metal resistant to oxidation (e.g., silver, gold). The proximity effect extends through the metal coating. With certain superconductors, non-noble metals can be used for the coating.

  8. Variation of Chemical Compounds of Sandalwood Oil From Various Provenances in Indonesia

    OpenAIRE

    Haryjanto, Liliek; Widowati, Titis Budi; Sumardi, Sumardi; Fiani, Ari; Hadiyan, Yayan

    2017-01-01

    The quality of sandalwood (Santalum album Linn) oil primarily depends on the compound of two major sesquiterpenes (α-santalol and β-santalol). The aim of this research was to identify variation of chemical compounds of sandalwood oil from various provenances. Fifty four samples from 8 provenances and one land race taken from 13th years old sandalwood planted at Gunungkidul, Yogyakarta Indonesia. Sandalwood powder were obtained by drilling tree at 10 cm above the ground horizontally. The sampl...

  9. Preparation process of an yttrium (or one rare earth), one alkaline earth metal, copper and oxygen superconductive compound

    International Nuclear Information System (INIS)

    Michel, C.; Pham Ai-Qooc; Raveau, B.

    1991-01-01

    The present invention describes the fabrication at atmospheric pressure of a compound based on yttrium (or a rare earth), one alkaline earth metal, copper, and oxygen so as to get a high-tc superconductor material. 2 refs

  10. FilTer BaSe: A web accessible chemical database for small compound libraries.

    Science.gov (United States)

    Kolte, Baban S; Londhe, Sanjay R; Solanki, Bhushan R; Gacche, Rajesh N; Meshram, Rohan J

    2018-03-01

    Finding novel chemical agents for targeting disease associated drug targets often requires screening of large number of new chemical libraries. In silico methods are generally implemented at initial stages for virtual screening. Filtering of such compound libraries on physicochemical and substructure ground is done to ensure elimination of compounds with undesired chemical properties. Filtering procedure, is redundant, time consuming and requires efficient bioinformatics/computer manpower along with high end software involving huge capital investment that forms a major obstacle in drug discovery projects in academic setup. We present an open source resource, FilTer BaSe- a chemoinformatics platform (http://bioinfo.net.in/filterbase/) that host fully filtered, ready to use compound libraries with workable size. The resource also hosts a database that enables efficient searching the chemical space of around 348,000 compounds on the basis of physicochemical and substructure properties. Ready to use compound libraries and database presented here is expected to aid a helping hand for new drug developers and medicinal chemists. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Variation of cuticular chemical compounds in three species of Mischocyttarus (Hymenoptera: Vespidae eusocial wasps

    Directory of Open Access Journals (Sweden)

    Eva Ramona Pereira Soares

    Full Text Available Abstract The social wasps have a remarkable system of organization in which chemical communication mediate different behavioral interactions. Among the compounds involved in this process, cuticular hydrocarbons are considered the main signals for nestmate recognition, caste differentiation, and fertility communication. The aims of this study were to describe the cuticular chemical compounds of the species Mischocyttarus consimilis, Mischocyttarus bertonii, and Mischocyttarus latior, and to test whether these chemical compounds could be used to evaluate differences and similarities between Mischocyttarus species, using gas chromatography coupled to mass spectrometry (GC-MS. Workers from these three species presented a variety of hydrocarbons ranging from C17 to C37, and among the compounds identified, the most representative were branched alkanes, linear alkanes and alkenes. The results revealed quantitative and qualitative differences among the hydrocarbon profiles, as confirmed by discriminant analysis. This study supports the hypothesis that cuticular chemical profiles can be used as parameters to identify interspecific and intercolony differences in Mischocyttarus, highlighting the importance of these compounds for differentiation of species and populations.

  12. Chemical-genetic profile analysis of five inhibitory compounds in yeast.

    Science.gov (United States)

    Alamgir, Md; Erukova, Veronika; Jessulat, Matthew; Azizi, Ali; Golshani, Ashkan

    2010-08-06

    Chemical-genetic profiling of inhibitory compounds can lead to identification of their modes of action. These profiles can help elucidate the complex interactions between small bioactive compounds and the cell machinery, and explain putative gene function(s). Colony size reduction was used to investigate the chemical-genetic profile of cycloheximide, 3-amino-1,2,4-triazole, paromomycin, streptomycin and neomycin in the yeast Saccharomyces cerevisiae. These compounds target the process of protein biosynthesis. More than 70,000 strains were analyzed from the array of gene deletion mutant yeast strains. As expected, the overall profiles of the tested compounds were similar, with deletions for genes involved in protein biosynthesis being the major category followed by metabolism. This implies that novel genes involved in protein biosynthesis could be identified from these profiles. Further investigations were carried out to assess the activity of three profiled genes in the process of protein biosynthesis using relative fitness of double mutants and other genetic assays. Chemical-genetic profiles provide insight into the molecular mechanism(s) of the examined compounds by elucidating their potential primary and secondary cellular target sites. Our follow-up investigations into the activity of three profiled genes in the process of protein biosynthesis provided further evidence concerning the usefulness of chemical-genetic analyses for annotating gene functions. We termed these genes TAE2, TAE3 and TAE4 for translation associated elements 2-4.

  13. Chemical-genetic profile analysis of five inhibitory compounds in yeast

    Directory of Open Access Journals (Sweden)

    Alamgir Md

    2010-08-01

    Full Text Available Abstract Background Chemical-genetic profiling of inhibitory compounds can lead to identification of their modes of action. These profiles can help elucidate the complex interactions between small bioactive compounds and the cell machinery, and explain putative gene function(s. Results Colony size reduction was used to investigate the chemical-genetic profile of cycloheximide, 3-amino-1,2,4-triazole, paromomycin, streptomycin and neomycin in the yeast Saccharomyces cerevisiae. These compounds target the process of protein biosynthesis. More than 70,000 strains were analyzed from the array of gene deletion mutant yeast strains. As expected, the overall profiles of the tested compounds were similar, with deletions for genes involved in protein biosynthesis being the major category followed by metabolism. This implies that novel genes involved in protein biosynthesis could be identified from these profiles. Further investigations were carried out to assess the activity of three profiled genes in the process of protein biosynthesis using relative fitness of double mutants and other genetic assays. Conclusion Chemical-genetic profiles provide insight into the molecular mechanism(s of the examined compounds by elucidating their potential primary and secondary cellular target sites. Our follow-up investigations into the activity of three profiled genes in the process of protein biosynthesis provided further evidence concerning the usefulness of chemical-genetic analyses for annotating gene functions. We termed these genes TAE2, TAE3 and TAE4 for translation associated elements 2-4.

  14. Superconductivity fundamentals and applications

    CERN Document Server

    Buckel, Werner

    2004-01-01

    This is the second English edition of what has become one of the definitive works on superconductivity in German -- currently in its sixth edition. Comprehensive and easy to understand, this introductory text is written especially with the non-specialist in mind. The authors, both long-term experts in this field, present the fundamental considerations without the need for extensive mathematics, describing the various phenomena connected with the superconducting state, with liberal insertion of experimental facts and examples for modern applications. While all fields of superconducting phenomena are dealt with in detail, this new edition pays particular attention to the groundbreaking discovery of magnesium diboride and the current developments in this field. In addition, a new chapter provides an overview of the elements, alloys and compounds where superconductivity has been observed in experiments, together with their major characteristics. The chapter on technical applications has been considerably expanded...

  15. Formation of biologically relevant compounds of interest in chemical evolution from the radiolysis of succinonitrile solutions

    International Nuclear Information System (INIS)

    Albarran, G.; Juarez, C.; Negron-Mendoza, A.

    1991-01-01

    Low molecular weight compounds such as H 2 , CO 2 , NH 3 were identified among the radiolytic products. Irradiated samples exhibit positive biuret test. IR spectra of the dry residue confirm the presence of amide groups. These results suggest the presence of peptidic type material, which increased with the radiation dose. Other compounds identified were several di and tricarboxylic acids. The initial yield of formation of a variety of products was calculated from the concentration vs dose plots. Some of the radiolytic compounds are of biological importance and their formation is significant to chemical evolution studies. (author) 7 refs

  16. Biological characterization of chemically diverse compounds targeting the Plasmodium falciparum coenzyme A synthesis pathway

    Directory of Open Access Journals (Sweden)

    Sabine Fletcher

    2016-11-01

    Full Text Available Abstract Background In the fight against malaria, the discovery of chemical compounds with a novel mode of action and/or chemistry distinct from currently used drugs is vital to counteract the parasite’s known ability to develop drug resistance. Another desirable aspect is efficacy against gametocytes, the sexual developmental stage of the parasite which enables the transmission through Anopheles vectors. Using a chemical rescue approach, we previously identified compounds targeting Plasmodium falciparum coenzyme A (CoA synthesis or utilization, a promising target that has not yet been exploited in anti-malarial drug development. Results We report on the outcomes of a series of biological tests that help to define the species- and stage-specificity, as well as the potential targets of these chemically diverse compounds. Compound activity against P. falciparum gametocytes was determined to assess stage-specificity and transmission-reducing potential. Against early stage gametocytes IC50 values ranging between 60 nM and 7.5 μM were obtained. With the exception of two compounds with sub-micromolar potencies across all intra-erythrocytic stages, activity against late stage gametocytes was lower. None of the compounds were specific pantothenate kinase inhibitors. Chemical rescue profiling with CoA pathway intermediates demonstrated that most compounds acted on either of the two final P. falciparum CoA synthesis enzymes, phosphopantetheine adenylyltransferase (PPAT or dephospho CoA kinase (DPCK. The most active compound targeted either phosphopantothenoylcysteine synthetase (PPCS or phosphopantothenoylcysteine decarboxylase (PPCDC. Species-specificity was evaluated against Trypanosoma cruzi and Trypanosoma brucei brucei. No specific activity against T. cruzi amastigotes was observed; however three compounds inhibited the viability of trypomastigotes with sub-micromolar potencies and were confirmed to act on T. b. brucei CoA synthesis. Conclusions

  17. The Periodic Table as a Part of the Periodic Table of Chemical Compounds

    OpenAIRE

    Labushev, Mikhail M.

    2011-01-01

    The numbers of natural chemical elements, minerals, inorganic and organic chemical compounds are determined by 1, 2, 3 and 4-combinations of a set 95 and are respectively equal to 95, 4,465, 138,415 and 3,183,545. To explain these relations it is suggested the concept of information coefficient of proportionality as mathematical generalization of the proportionality coefficient for any set of positive numbers. It is suggested a hypothesis that the unimodal distributions of the sets of informa...

  18. Irradiation defects in the A-15 compounds V3Si and Nb3Ge: effects on superconducting and transport properties

    International Nuclear Information System (INIS)

    Rullier-Albenque, F.

    1984-11-01

    In the first part the mechanisms of atomic displacements under electron irradiation in these diatomic ordered solids are studied. In the case of superconducting alloys, simultaneous measurements of electrical resistivity at 20 K and critical temperature allow to distinguish the influence of point defects created in each sub-lattice and antisite defects. The threshold energies have been determined. In the case of V 3 Si, Frenkel pairs have been characterized by their specific resistivities and the decrease of Tsub(c) by vanadium vacancies. The Tsub(c) results obtained on V 3 Si also reveal the existence of a threshold electron energy to produce antisite defects. The second part is a comparative study of irradiation effects in Nb 3 Ge with very different kinds of projectiles: 2.5 MeV electrons, fast neutrons or 100 MeV heavy ions (uranium fission fragments). For these three types of irradiation, resistivity and critical temperature damage can be described in terms of point defects: Frenkel pairs and antisite defects. In the third part we have studied the influence of 2.5 MeV electron or fission fragment-irradiation on the resistivity versus temperature curves of Nb 3 Ge. For both projectiles, negative temperature coefficients of resistivity drho)/dT, were measured and correlated with resistivity at 280 K and 25 K. These anomalous transport properties are related to an electron localization process assisted by electron-phonon and electron-electron interaction [fr

  19. Relationships between chemical structure and rat repellency. II. Compounds screened between 1950 and 1960

    Science.gov (United States)

    Bowles, W.A.; Adomaitis, V.A.; DeWitt, J.B.; Pratt, J.J.

    1974-01-01

    Over 4,600 compounds, chiefly organic types, were evaluated using both a food acceptance test (Part A) and a barrier penetration bioassay (Part B), to correlate relationships between chemical structure and rodent repellency.These chemicals are indexed and classified according to the functional groups present and to the degree of substitution within their molecular structures. The results of reduction in foot consumption for each compound appraised are calculated and their K values listed in Table I.The repellent activities of the functional groups represented, alone or in combinations, are expressed in Table II by a Functional Group Repellency Index. A ranking of these indices suggests that acyclic and heteroyclic compounds containing tri- or pentavalent nitrogen would be a parent compound of choice for synthesizing novel repellents. Other molecular arrangements, spatial configurations and combinations of functional groups are compared.There were 123 active, interesting or promising compounds included in the 699 having K values of 85 or greater, which were selected for the barrier appraisal study. These chemicals were formulated in selective solvents at several concentrations and applied to burlap. Small foot bags were fashioned using the fabric impregnated with the candidate formulation, and exposed to rodent attack following storage periods of varying intervals. The results of these tests are listed in Table III. Again, those compounds containing nitrogen in the functional groupings indicated a high order of effectiveness. Several commercial patents covering rodent repellents were issued using the data from the food acceptance and barrier studies.Organizations and cooperators which supplied samples for the program are listed in Appendix I. The Wiswesser cipher for compounds in Table I is used in Appendix II to facilitate location of chemicals by sample code number as they appear under the index headings, and for computer storage and analysis.

  20. Relationships between chemical structure and rat repellency: II. compounds screened between 1950 and 1960

    Science.gov (United States)

    Bowles, Walter A.; Adomaitis, V.A.; DeWitt, J.B.; Pratt, J.J.

    1974-01-01

    Over 4,600 compounds, chiefly organic types, were evaluated using both a food acceptance test (Part A) and a barrier penetration bioassay (Part B), to correlate relationships between chemical structure and rodent repellency. These chemicals are indexed and classified according to the functional groups present and to the degree of substitution within their molecular structures. The results of reduction in food consumption for each compound appraised are calculated and their K values listed in Table 1. The repellent activities of the functional groups represented, alone or in combinations, are expressed in Table II by a Functional Group Repellency Index.. A ranking of these indices suggests that acyclic and heteroyclic compounds containing tri- or pentavalent nitrogen would be a parent compound of choice for synthesizing novel repellents. Other molecular arrangements, spatial configurations and combinations of functional groups are compared. There were 123 active, interesting or promising compounds included in the 699 having K values of 85 or greater, which were selected for the barrier appraisal study. These chemicals were formulated in selective solvents at several concentrations and applied to burlap. Small food bags were fashioned using the fabric impregnated with the candidate formulation, and exposed to rodent attack following storage periods of varying intervals. The results of these tests are listed in Table III. Again, those compounds containing nitrogen in the functional groupings indicated a high order of effectiveness. Several commercial patents covering rodent repellents were issued using the data from the food acceptance and barrier studies. Organizations and cooperators which supplied samples for the program are listed in Appendix I. The Wiswesser cipher for compounds in Table I is used in Appendix II to facilitate location of chemicals by sample code number as they appear under the index headings, and for computer storage and analysis.

  1. Development of corresponding states model for estimation of the surface tension of chemical compounds

    DEFF Research Database (Denmark)

    Gharagheizi, Farhad; Eslamimanesh, Ali; Sattari, Mehdi

    2013-01-01

    The gene expression programming (GEP) strategy is applied for presenting two corresponding states models to represent/predict the surface tension of about 1,700 compounds (mostly organic) from 75 chemical families at various temperatures collected from the DIPPR 801 database. The models parameter...

  2. Monitoring the Evolution of Major Chemical Compound in Dairy Products During Shelf-Life by FTIR

    Directory of Open Access Journals (Sweden)

    Adriana Păucean

    2014-11-01

    Full Text Available Fourier-transform infrared (FTIR spectroscopy is considered to be a comprehensive and sensitive method to characterize the chemical composition and for detection of molecular changes in different samples. In this study, FTIRspectroscopy  was employed as an rapid and low-cost technique in order to characterize the FTIR spectra and identify appropriate spectral regions for dairy product fermented by a lactic culture consisting by species of Lactococcus lactis and Leuconostoc mesenteroides. A second objective was to monitore the key chemical compounds (lactose, lactic acid, flavors during fermentation and refrigerated storage (1-21 days, at 4-6°C. By FT-IR fingerprint during fermentation we identified changes of the spectra pattern with specific increasing or decreasing peaks for lactose, lactic acid, esters, aromatic compounds, aminoacids, fatty acids. Also the technique was able to identify chemical compounds involved in the microbial activity such as phosphates and phosphorylated carbohydrates during fermentation and dairy product shelf-life. All the major chemical compounds recorded significant increaments during fermentation and refrigerated storage comparing with the raw milk.

  3. Phenolic Melatonin-Related Compounds: Their Role as Chemical Protectors against Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Annia Galano

    2016-10-01

    Full Text Available There is currently no doubt about the serious threat that oxidative stress (OS poses to human health. Therefore, a crucial strategy to maintain a good health status is to identify molecules capable of offering protection against OS through chemical routes. Based on the known efficiency of the phenolic and melatonin (MLT families of compounds as antioxidants, it is logical to assume that phenolic MLT-related compounds should be (at least equally efficient. Unfortunately, they have been less investigated than phenols, MLT and its non-phenolic metabolites in this context. The evidence reviewed here strongly suggests that MLT phenolic derivatives can act as both primary and secondary antioxidants, exerting their protection through diverse chemical routes. They all seem to be better free radical scavengers than MLT and Trolox, while some of them also surpass ascorbic acid and resveratrol. However, there are still many aspects that deserve further investigations for this kind of compounds.

  4. Chemical compounds toxic to invertebrates isolated from marine cyanobacteria of potential relevance to the agricultural industry.

    Science.gov (United States)

    Essack, Magbubah; Alzubaidy, Hanin S; Bajic, Vladimir B; Archer, John A C

    2014-10-29

    In spite of advances in invertebrate pest management, the agricultural industry is suffering from impeded pest control exacerbated by global climate changes that have altered rain patterns to favour opportunistic breeding. Thus, novel naturally derived chemical compounds toxic to both terrestrial and aquatic invertebrates are of interest, as potential pesticides. In this regard, marine cyanobacterium-derived metabolites that are toxic to both terrestrial and aquatic invertebrates continue to be a promising, but neglected, source of potential pesticides. A PubMed query combined with hand-curation of the information from retrieved articles allowed for the identification of 36 cyanobacteria-derived chemical compounds experimentally confirmed as being toxic to invertebrates. These compounds are discussed in this review.

  5. Chemical Compounds Toxic to Invertebrates Isolated from Marine Cyanobacteria of Potential Relevance to the Agricultural Industry

    KAUST Repository

    Essack, Magbubah

    2014-10-29

    In spite of advances in invertebrate pest management, the agricultural industry is suffering from impeded pest control exacerbated by global climate changes that have altered rain patterns to favour opportunistic breeding. Thus, novel naturally derived chemical compounds toxic to both terrestrial and aquatic invertebrates are of interest, as potential pesticides. In this regard, marine cyanobacterium-derived metabolites that are toxic to both terrestrial and aquatic invertebrates continue to be a promising, but neglected, source of potential pesticides. A PubMed query combined with hand-curation of the information from retrieved articles allowed for the identification of 36 cyanobacteria-derived chemical compounds experimentally confirmed as being toxic to invertebrates. These compounds are discussed in this review.

  6. Chemical Compounds Toxic to Invertebrates Isolated from Marine Cyanobacteria of Potential Relevance to the Agricultural Industry

    Directory of Open Access Journals (Sweden)

    Magbubah Essack

    2014-10-01

    Full Text Available In spite of advances in invertebrate pest management, the agricultural industry is suffering from impeded pest control exacerbated by global climate changes that have altered rain patterns to favour opportunistic breeding. Thus, novel naturally derived chemical compounds toxic to both terrestrial and aquatic invertebrates are of interest, as potential pesticides. In this regard, marine cyanobacterium-derived metabolites that are toxic to both terrestrial and aquatic invertebrates continue to be a promising, but neglected, source of potential pesticides. A PubMed query combined with hand-curation of the information from retrieved articles allowed for the identification of 36 cyanobacteria-derived chemical compounds experimentally confirmed as being toxic to invertebrates. These compounds are discussed in this review.

  7. Chemical fate and biological effects of several endocrine disrupters compounds in two echinoderm species.

    Science.gov (United States)

    Sugni, Michela; Tremolada, Paolo; Porte, Cinta; Barbaglio, Alice; Bonasoro, Francesco; Carnevali, M Daniela Candia

    2010-03-01

    Two echinoderm species, the sea urchin Paracentrotus lividus and the feather star Antedon mediterranea, were exposed for 28 days to several EDCs: three putative androgenic compounds, triphenyltin (TPT), fenarimol (FEN), methyltestosterone (MET), and two putative antiandrogenic compounds, p,p'-DDE (DDE) and cyproterone acetate (CPA). The exposure nominal concentrations were from 10 to 3000 ng L(-1), depending on the compound. This paper is an attempt to join three different aspects coming from our ecotoxicological tests: (1) the chemical behaviour inside the experimental system; (2) the measured toxicological endpoints; (3) the biochemical responses, to which the measured endpoints may depend. The chemical fate of the different compounds was enquired by a modelling approach throughout the application of the 'Aquarium model'. An estimation of the day-to-day concentration levels in water and biota were obtained together with the amount assumed each day by each animal (uptake in microg animal(-1) d(-1) or ng g-wet weight(-1) d(-1)). The toxicological endpoints investigated deal with the reproductive potential (gonad maturation stage, gonad index and oocyte diameter) and with the regenerative potential (growth and histology). Almost all the compounds exerted some kind of effect at the tested concentrations, however TPT was the most effective in altering both reproductive and regenerative parameters (also at the concentration of few ng L(-1)). The biochemical analyses of testosterone (T) and 17beta-estradiol (E(2)) also showed the ability of the selected compounds to significantly alter endogenous steroid concentrations.

  8. Exploring sources of biogenic secondary organic aerosol compounds using chemical analysis and the FLEXPART model

    Science.gov (United States)

    Martinsson, Johan; Monteil, Guillaume; Sporre, Moa K.; Kaldal Hansen, Anne Maria; Kristensson, Adam; Eriksson Stenström, Kristina; Swietlicki, Erik; Glasius, Marianne

    2017-09-01

    Molecular tracers in secondary organic aerosols (SOAs) can provide information on origin of SOA, as well as regional scale processes involved in their formation. In this study 9 carboxylic acids, 11 organosulfates (OSs) and 2 nitrooxy organosulfates (NOSs) were determined in daily aerosol particle filter samples from Vavihill measurement station in southern Sweden during June and July 2012. Several of the observed compounds are photo-oxidation products from biogenic volatile organic compounds (BVOCs). Highest average mass concentrations were observed for carboxylic acids derived from fatty acids and monoterpenes (12. 3 ± 15. 6 and 13. 8 ± 11. 6 ng m-3, respectively). The FLEXPART model was used to link nine specific surface types to single measured compounds. It was found that the surface category sea and ocean was dominating the air mass exposure (56 %) but contributed to low mass concentration of observed chemical compounds. A principal component (PC) analysis identified four components, where the one with highest explanatory power (49 %) displayed clear impact of coniferous forest on measured mass concentration of a majority of the compounds. The three remaining PCs were more difficult to interpret, although azelaic, suberic, and pimelic acid were closely related to each other but not to any clear surface category. Hence, future studies should aim to deduce the biogenic sources and surface category of these compounds. This study bridges micro-level chemical speciation to air mass surface exposure at the macro level.

  9. Exploring sources of biogenic secondary organic aerosol compounds using chemical analysis and the FLEXPART model

    Directory of Open Access Journals (Sweden)

    J. Martinsson

    2017-09-01

    Full Text Available Molecular tracers in secondary organic aerosols (SOAs can provide information on origin of SOA, as well as regional scale processes involved in their formation. In this study 9 carboxylic acids, 11 organosulfates (OSs and 2 nitrooxy organosulfates (NOSs were determined in daily aerosol particle filter samples from Vavihill measurement station in southern Sweden during June and July 2012. Several of the observed compounds are photo-oxidation products from biogenic volatile organic compounds (BVOCs. Highest average mass concentrations were observed for carboxylic acids derived from fatty acids and monoterpenes (12. 3 ± 15. 6 and 13. 8 ± 11. 6 ng m−3, respectively. The FLEXPART model was used to link nine specific surface types to single measured compounds. It was found that the surface category sea and ocean was dominating the air mass exposure (56 % but contributed to low mass concentration of observed chemical compounds. A principal component (PC analysis identified four components, where the one with highest explanatory power (49 % displayed clear impact of coniferous forest on measured mass concentration of a majority of the compounds. The three remaining PCs were more difficult to interpret, although azelaic, suberic, and pimelic acid were closely related to each other but not to any clear surface category. Hence, future studies should aim to deduce the biogenic sources and surface category of these compounds. This study bridges micro-level chemical speciation to air mass surface exposure at the macro level.

  10. Low-temperature in situ formation of Y-Ba-Cu-O high Tc superconducting thin films by plasma-enhanced metalorganic chemical vapor deposition

    Science.gov (United States)

    Zhao, J.; Noh, D. W.; Chern, C.; Li, Y. Q.; Norris, P.; Gallois, B.; Kear, B.

    1990-06-01

    Highly textured, highly dense, superconducting YBa2Cu3O7-x thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 °C by a remote microwave plasma-enhanced metalorganic chemical vapor deposition process (PE-MOCVD). Nitrous oxide was used as the oxidizer gas. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K. PE-MOCVD was carried out in a commercial scale MOCVD reactor.

  11. Superconducting YBa2Cu3O7 - x thin films on silver substrates by in situ plasma-enhanced metalorganic chemical vapor deposition

    Science.gov (United States)

    Zhao, J.; Li, Y. Q.; Chern, C. S.; Norris, P.; Gallois, B.; Kear, B.; Wessels, B. W.

    1991-01-01

    An in situ microwave plasma-enhanced metalorganic chemical vapor deposition process was used to fabricate highly c-axis oriented YBa2Cu3O7-x superconducting thin films on metallic Ag substrates. The films were deposited at a reduced substrate temperature of 740 °C in about 270 Pa of N2O ambient. Magnetic susceptibilities versus temperature of the as-deposited films show attainment of zero resistance of 85 K and composition of single (high Tc) phase. X-ray diffraction measurements reveal that the films deposited at 740 °C have highly preferential orientation of the crystallite c axes perpendicular to the substrate surface.

  12. Structural and superconducting properties of La2−xNdxCuO4+y (0≤x≤0.5) prepared by room temperature chemical oxidation

    DEFF Research Database (Denmark)

    Rial, C.; Morán, E.; Alario-Franco, M.A.

    1997-01-01

    The systematic characterization of the structural and superconducting properties of room temperature chemically oxidized T/O La2-xNdxCuO4+y (0 less than or equal to x less than or equal to 0.5) has been performed by neutron powder diffraction and magnetic susceptibility measurements. Similarities...... and differences as regards the modifications induced by interstitial oxygen in these materials and in related La2-xMxCuO4+y (M = Ca, Sr, Pa) are discussed....

  13. Effect of impregnation of ZrO2 on the chemical stability and the superconductivity of Y- and Bi-systems

    International Nuclear Information System (INIS)

    Muroya, Masaaki; Minamiyama, Hideaki

    1994-01-01

    The results are given concerning the influence of impregnation of Zr on chemical stability and superconductivity of YBa 2 (Cu 1-x · Zr x ) 3 O 7-y (123-system) and Bi 1.84 Zr x Pb 0.34 Sr 1.91 Ca 2.03 Cu 3.06 O y (2223-system) superconductors, when the samples are contacted with the solutions of acid (pH3), distilled water (pH5.6) and base (pH9), where x = 0-0.35. It is concluded that the low chemical stability was found in the case of YBZCO, barium hydroxide and/or barium carbonate were precipitated into the solutions, even though mechanical strength was increased by impregnation of Zr, and the chemical stability of Bi-system is high compared with that of the Y-system. 8 refs., 5 figs

  14. Superconductivity up to 114 K in the Bi-Al-Ca-Sr-Cu-O compound system without rare-earth elements

    Science.gov (United States)

    Chu, C. W.; Bechtold, J.; Gao, L.; Hor, P. H.; Huang, Z. J.

    1988-01-01

    Stable superconductivity up to 114 K has been reproducibly detected in Bi-Al-Ca-Sr-Cu-O multiphase systems without any rare-earth elements. Pressure has only a slight positive effect on T(c). These observations provide an extra material base for the study of the mechanism of high-temperature superconductivity and also the prospect of reduced material cost for future applications of superconductivity.

  15. Parallelization of enumerating tree-like chemical compounds by breadth-first search order

    Science.gov (United States)

    2015-01-01

    Enumeration of chemical compounds greatly assists designing and finding new drugs, and determining chemical structures from mass spectrometry. In our previous study, we developed efficient algorithms, BfsSimEnum and BfsMulEnum for enumerating tree-like chemical compounds without and with multiple bonds, respectively. For many instances, our previously proposed algorithms were able to enumerate chemical structures faster than other existing methods. Latest processors consist of multiple processing cores, and are able to execute many tasks at the same time. In this paper, we develop three parallelized algorithms BfsEnumP1-3 by modifying BfsSimEnum in simple manners to further reduce execution time. BfsSimEnum constructs a family tree in which each vertex denotes a molecular tree. BfsEnumP1-3 divide a set of vertices with some given depth of the family tree into several subsets, each of which is assigned to each processor. For evaluation, we perform experiments for several instances with varying the division depth and the number of processors, and show that BfsEnumP1-3 are useful to reduce the execution time for enumeration of tree-like chemical compounds. In addition, we show that BfsEnumP3 achieves more than 80% parallelization efficiency using up to 11 processors, and reduce the execution time using 12 processors to about 1/10 of that by BfsSimEnum. PMID:26044861

  16. Biological and chemical investigation of Allium cepa L. response to selenium inorganic compounds.

    Science.gov (United States)

    Michalska-Kacymirow, M; Kurek, E; Smolis, A; Wierzbicka, M; Bulska, E

    2014-06-01

    The aim of this study was to evaluate the biological and chemical response of Allium cepa L. exposed to inorganic selenium compounds. Besides the investigation of the total content of selenium as well as its chemical speciation, the Allium test was used to evaluate the growth of onion roots and mitotic activity in the roots' meristem. The total content of selenium was determined by inductively coupled plasma mass spectrometry (ICP MS). High-performance liquid chromatography (HPLC), coupled to ICP MS, was used for the selenium chemical speciation. Results indicated that A. cepa plants are able to biotransform inorganic selenium compounds into their organic derivatives, e.g., Se-methylselenocysteine from the Se(IV) inorganic precursor. Although the differences in the biotransformation of selenium are due mainly to the oxidation state of selenium, the experiment has also shown a fine effect of counter ions (H(+), Na(+), NH4 (+)) on the response of plants and on the specific metabolism of selenium.

  17. Superconducting properties, chemical compositions, and lattice parameters of Pb-, Sn- and (Pb1-xSnx)Mo6S8

    International Nuclear Information System (INIS)

    Sadakata, N.; Corderman, R.; Asano, T.; Cox, D.; Suenaga, M.; Foner, S.; McNiff, E.J. Jr.

    1991-01-01

    The values of critical temperatures for alloys of Pb- and SnMo 6 S 8 were shown to be lower than those of the respective pure Chevrel phases. Chemical compositional analysis of the compounds revealed that the decreased T c in the alloys are due to the off-stoichiometric compositions in the alloys. Although alloying slightly increased the values of the upper critical field H c2 over that for PbMo 6 S 8 , the H c2 values for these specimens were substantially lower than those which have been reported for PbMo 6 S 8 . Possible causes for these depressed values of H c2 are discussed

  18. Survey of Chemical Compounds Tested In Vitro against Rumen Protozoa for Possible Control of Bloat

    Science.gov (United States)

    Willard, F. L.; Kodras, Rudolph

    1967-01-01

    Over 170 chemical agents were screened for antiprotozoal action in bovine ruminal fluid. Compounds were tested at 0.1 and 0.05% concentrations. Tested compounds included inorganic compounds, antibiotics, biocides, neuromuscular agents, arsenicals, plant and animal hormones, antimalarials, surface-active agents, anthelmintics, and many others. The most active compounds were cupric sulfate, nickel sulfate, nitrofurazone, hydrogen peroxide, dodecyl sodium sulfate, pelargonic acid, iodoacetic acid, 1-diethylaminoethylamino-4-methylthiaxanthrone, sodium arsanilate, sodium arsenate, bismuth glycolyl arsanilate, 1-β-hydroxyethyl-2-methyl-5-nitroimidazole, and p-nitroaniline. Copper ion was not particularly effective against entodinia; nickel ion had no effect on holotrichs. Hydrogen peroxide and iodoacetic acid were effective at a concentration of 0.005%. Anionic surface-active agents were very effective, especially long-chain sulfates and phosphates. These antiprotozoal agents warrant further in vivo studies for possible use in treating or curing bloat in ruminants. PMID:6077407

  19. Identification of chemical compounds of Nardostachys Jatamansi essence available in Iran

    Directory of Open Access Journals (Sweden)

    Ghassemi-Dehkordi Nasrolah

    2014-04-01

    Full Text Available Introduction: With regard to using drugs with plant origin and with the aim of suitable use of these types of drugs and preventing them to be abused, it is necessary to determine the standards of these plants. The aim of the present study was to identify and study chemical compounds of Nardostachys Jatamansi essence in Iran and define monograph of this plant for the Iranian plant pharmacopeia. Methods: In an experimental study the Nardostachys Jatamansi specimen was prepared from the market in Iran. The essence of the plant was prepared by the hydro-distillation in Clevenger apparatus. Essence was obtained as a greenish yellow oil layer with the 0.07 % yield. The essence compounds were identified quantitatively by Gas Chromatography-Mass Spectroscopy (GC/MS method. Results: Totally, 29 compounds were identified in Nardostachys Jatamansi essence. The retention indexes (RI were only similar with overall standard values in two compounds like mesitylene and P-cymene. In this line the RI values about three compounds of valerenic acid, palmitic acid, and valerenyl isovalerate were determined significantly higher than standard values of RI. Conclusion: The essence prepared from the Nardostachys Jatamansi plant in Iran was different in terms of some compounds and components including valerenic acid, palmitic acid, and valerenyl isovalerate and so it is necessary to identify and register quality and quantity characteristics of compounds available in this plat in the Iranian medicinal plants pharmacopeia.

  20. Efficacy of potential chemical control compounds for removing invasive American bullfrogs (Rana catesbeiana).

    Science.gov (United States)

    Witmer, Gary W; Snow, Nathan P; Moulton, Rachael S

    2015-01-01

    Invasive American bullfrogs [Rana catesbeiana (Lithobates catesbeianus)] are outcompeting and predating on native biota and contributing to reductions in biodiversity worldwide. Current methods for controlling American bullfrogs are incapable of stopping their expansion, thus more cost-effective and broadly applicable methods are needed. Although chemical control compounds have been identified as effective for removing other invasive amphibians, none have been tested for American bullfrogs. Our objective was to expand on previous research and test the efficacy of 10 potential chemical control compounds for removing invasive American bullfrogs. After a dermal spray-application of 4 ml, we found 3 compounds (i.e., chloroxylenol, rotenone with permethrin, and caffeine) at 5-10 % concentrations in water were 100 % lethal for adult American bullfrogs. Chloroxylenol and rotenone with permethrin were fast acting with time-to-death <2 h. This research presents a first-step toward incorporating chemical control as part of integrated pest management strategy for controlling invasive American bullfrogs. Follow-up studies on delivery systems and reducing non-target hazards should ensue with these compounds to confirm their effectiveness and safety for removing invasive American bullfrogs.

  1. Molecular design chemical structure generation from the properties of pure organic compounds

    CERN Document Server

    Horvath, AL

    1992-01-01

    This book is a systematic presentation of the methods that have been developed for the interpretation of molecular modeling to the design of new chemicals. The main feature of the compilation is the co-ordination of the various scientific disciplines required for the generation of new compounds. The five chapters deal with such areas as structure and properties of organic compounds, relationships between structure and properties, and models for structure generation. The subject is covered in sufficient depth to provide readers with the necessary background to understand the modeling

  2. Country-specific chemical signatures of persistent environmental compounds in breast milk

    DEFF Research Database (Denmark)

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

    2010-01-01

    , exhibits much lower incidences of these disorders. The reasons behind the observed trends are unexplained, but environmental endocrine disrupting chemicals (EDCs) that affect foetal testis development are probably involved. Levels of persistent chemicals in breast milk can be considered a proxy...... for exposure of the foetus to such agents. Therefore, we undertook a comprehensive ecological study of 121 EDCs, including the persistent compounds dioxins, polychlorinated biphenyls (PCBs), pesticides and flame retardants, and non-persistent phthalates, in 68 breast milk samples from Denmark and Finland...... to compare exposure of mothers to this environmental mixture of EDCs. Using sophisticated, bioinformatic tools in our analysis, we reveal, for the first time, distinct country-specific chemical signatures of EDCs with Danes having generally higher exposure than Finns to persistent bioaccumulative chemicals...

  3. Superconductivity and magnetism in the oxypnictides: high field ESR and {mu}SR studies of (La,Gd)FeAsO{sub 1-x}F{sub x} compounds

    Energy Technology Data Exchange (ETDEWEB)

    Muranyi, Ferenc [Physics Institute, University of Zuerich (Switzerland); IFW Dresden (Germany); Alfonsov, Alexey; Kataev, Vladislav; Koehler, Anke; Werner, Jochen; Behr, Guenter; Leps, Norman; Klingeler, Ruediger; Kondrat, Agnieszka; Hess, Christian; Buechner, Bernd [IFW Dresden (Germany); Khasanov, Rustem; Luetkens, Hubertus [Paul Scherrer Institut, Villigen PSI (Switzerland); Klaus, Hans-Henning [IFP, TU Dresden (Germany)

    2009-07-01

    The discovery of a new class of superconducting materials, ReFeAsO{sub 1-x}F{sub x}, stirred up the scientific community. Here we report the Gd{sup 3+} high field ESR study of differently doped (La,Gd)FeAsO{sub 1-x}F{sub x} compounds. In lightly Gd-doped LaFeAsO samples the SDW transition yields line-broadening at the transition temperature, the SDW transition is then suppressed upon F-doping. In the dense compound, GdFeAsO, with SDW transition around 140 K, the Gd-ESR was also studied. With 15% F-doping superconductivity appears at {proportional_to} 21 K. The SDW and SC transitions are clearly seen in ESR and in {mu} SR as well. Surprisingly the reminiscence of the SDW transition of the undoped material (GdFeAsO) was identified in the doped (15% F) compound at lower temperature ({proportional_to} 80 K). This indicates the importance of the the interplay between superconductivity and magnetism in oxypnictides.

  4. Superconductivity revisited

    CERN Document Server

    Dougherty, Ralph

    2013-01-01

    While the macroscopic phenomenon of superconductivity is well known and in practical use worldwide in many industries, including MRIs in medical diagnostics, the current theoretical paradigm for superconductivity (BCS theory) suffers from a number of limitations, not the least of which is an adequate explanation of high temperature superconductivity. This book reviews the current theory and its limitations and suggests new ideas and approaches in addressing these issues. The central objective of the book is to develop a new, coherent, understandable theory of superconductivity directly based on molecular quantum mechanics.

  5. Materials for superconducting cavities

    International Nuclear Information System (INIS)

    Bonin, B.

    1996-01-01

    The ideal material for superconducting cavities should exhibit a high critical temperature, a high critical field, and, above all, a low surface resistance. Unfortunately, these requirements can be conflicting and a compromise has to be found. To date, most superconducting cavities for accelerators are made of niobium. The reasons for this choice are discussed. Thin films of other materials such as NbN, Nb 3 Sn, or even YBCO compounds can also be envisaged and are presently investigated in various laboratories. It is shown that their success will depend critically on the crystalline perfection of these films. (author)

  6. Behavior of radon, chemical compounds and stable elements in underground water

    International Nuclear Information System (INIS)

    Lopez R, N.; Segovia, N.; Lopez, M.B.E.; Pena, P.; Armienta, M.A.; Godinez, L.; Seidel, J.L.

    2001-01-01

    The radon behavior, chemical compounds, major and trace elements in water samples of four springs and three wells of urban and agricultural zones around the Jocotitlan volcano and El Oro region was determined, both of them located in the medium part of the Mexican neo-volcanic axis. The 222 Rn was measured by the liquid scintillation method, the analysis of major components was realized with conventional chemical techniques, while the trace elements were quantified using an Icp-Ms. The average values of the radon concentrations obtained during one year were constant relatively, in an interval from 0.97 to 4.99 Bq/lt indicating a fast transport from the reload area toward the sampling points. the compounds, major and trace elements showed differences which indicate distinct origins of water from the site studies. (Author)

  7. Metal organic chemical vapor deposition of 111-v compounds on silicon

    Science.gov (United States)

    Vernon, Stanley M.

    1986-01-01

    Expitaxial composite comprising thin films of a Group III-V compound semiconductor such as gallium arsenide (GaAs) or gallium aluminum arsenide (GaAlAs) on single crystal silicon substrates are disclosed. Also disclosed is a process for manufacturing, by chemical deposition from the vapor phase, epitaxial composites as above described, and to semiconductor devices based on such epitaxial composites. The composites have particular utility for use in making light sensitive solid state solar cells.

  8. Optical methods for creating delivery systems of chemical compounds to plant roots

    Science.gov (United States)

    Kuznetsov, Pavel E.; Rogacheva, Svetlana M.; Arefeva, Oksana A.; Minin, Dmitryi V.; Tolmachev, Sergey A.; Kupadze, Machammad S.

    2004-08-01

    Spectrophotometric and fluorescence methods have been used for creation and investigation of various systems of target delivery of chemical compounds to roots of plants. The possibility of using liposomes, incrusted by polysaccharides of the external surface of nitrogen-fixing rizospheric bacteria Azospirillum brasilense SP 245, and nanoparticles incrusted by polysaccharides of wheat roots, as the named systems has been shown. The important role of polysaccharide-polysaccharide interaction in the adsorption processes of bacteria on wheat roots has been demonstrated.

  9. Chemical Compounds and Mechanisms Involved in the Formation and Stabilization of Foam in Sparkling Wines.

    Science.gov (United States)

    Kemp, Belinda; Condé, Bruna; Jégou, Sandrine; Howell, Kate; Vasserot, Yann; Marchal, Richard

    2018-02-08

    The visual properties of sparkling wine including foam and bubbles are an indicator of sparkling wine quality. Foam properties, particularly foam height (FH) and foam stability (TS), are significantly influenced by the chemical composition of the wine. This review investigates our current knowledge of specific chemical compounds and, the mechanisms by which they influence the foam properties of sparkling wines. Grape and yeast proteins, amino acids, polysaccharides, phenolic compounds, organic acids, fatty acids, ethanol and sugar are examined with respect to their contribution to foam characteristics in sparkling wines made with the traditional, transfer, and charmat and carbonation methods. Contradictory results have been identified that appear to be due to the analytical methods used to measure and quantify compounds and foam. Biopolymer complexes are discussed and absent knowledge with regards to thaumatin-like proteins (TLPs), polysaccharides, amino acids, oak-derived phenolic compounds and organic acids are identified. Future research is also likely to concentrate on visual analysis of sparkling wines by in-depth imaging analysis and specific sensory analysis techniques.

  10. Solvent Extraction of Chemical Attribution Signature Compounds from Painted Wall Board: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, Jon H.; Colburn, Heather A.

    2009-10-29

    This report summarizes work that developed a robust solvent extraction procedure for recovery of chemical attribution signature (CAS) compound dimethyl methyl phosphonate (DMMP) (as well as diethyl methyl phosphonate (DEMP), diethyl methyl phosphonothioate (DEMPT), and diisopropyl methyl phosphonate (DIMP)) from painted wall board (PWB), which was selected previously as the exposed media by the chemical attribution scientific working group (CASWG). An accelerated solvent extraction approach was examined to determine the most effective method of extraction from PWB. Three different solvent systems were examined, which varied in solvent strength and polarity (i.e., 1:1 dichloromethane : acetone,100% methanol, and 1% isopropanol in pentane) with a 1:1 methylene chloride : acetone mixture having the most robust and consistent extraction for four original target organophosphorus compounds. The optimum extraction solvent was determined based on the extraction efficiency of the target analytes from spiked painted wallboard as determined by gas chromatography x gas chromatography mass spectrometry (GCxGC-MS) analysis of the extract. An average extraction efficiency of approximately 60% was obtained for these four compounds. The extraction approach was further demonstrated by extracting and detecting the chemical impurities present in neat DMMP that was vapor-deposited onto painted wallboard tickets.

  11. Predicting the Absorption Potential of Chemical Compounds Through a Deep Learning Approach.

    Science.gov (United States)

    Shin, Moonshik; Jang, Donjin; Nam, Hojung; Lee, Kwang Hyung; Lee, Doheon

    2018-01-01

    The human colorectal carcinoma cell line (Caco-2) is a commonly used in-vitro test that predicts the absorption potential of orally administered drugs. In-silico prediction methods, based on the Caco-2 assay data, may increase the effectiveness of the high-throughput screening of new drug candidates. However, previously developed in-silico models that predict the Caco-2 cellular permeability of chemical compounds use handcrafted features that may be dataset-specific and induce over-fitting problems. Deep Neural Network (DNN) generates high-level features based on non-linear transformations for raw features, which provides high discriminant power and, therefore, creates a good generalized model. We present a DNN-based binary Caco-2 permeability classifier. Our model was constructed based on 663 chemical compounds with in-vitro Caco-2 apparent permeability data. Two hundred nine molecular descriptors are used for generating the high-level features during DNN model generation. Dropout regularization is applied to solve the over-fitting problem and the non-linear activation. The Rectified Linear Unit (ReLU) is adopted to reduce the vanishing gradient problem. The results demonstrate that the high-level features generated by the DNN are more robust than handcrafted features for predicting the cellular permeability of structurally diverse chemical compounds in Caco-2 cell lines.

  12. Cyanobacteria and microalgae: a renewable source of bioactive compounds and other chemicals.

    Science.gov (United States)

    Encarnação, Telma; Pais, Alberto A C C; Campos, Maria G; Burrows, Hugh D

    2015-01-01

    Microalgae and cyanobacteria are rich sources of many valuable compounds, including important bioactive and biotechnologically relevant chemicals. Their enormous biodiversity, and the consequent variability in the respective biochemical composition, make microalgae cultivations a promising resource for many novel chemically and biologically active molecules and compounds of high commercial value such as lipids and dyes. The nature of the chemicals produced can be manipulated by changing the cultivation media and conditions. Algae are extremely versatile because they can be adapted to a variety of cell culture conditions. They do not require arable land, can be cultivated on saline water and wastewaters, and require much less water than plants. They possess an extremely high growth rate making these microorganisms very attractive for use in biofuel production--some species of algae can achieve around 100 times more oil than oil seeds. In addition, microalgae and cyanobacteria can accumulate various biotoxins and can contribute to mitigate greenhouse gases since they produce biomass through carbon dioxide fixation. In this review, we provide an overview of the application of microalgae in the production of bioactive and other chemicals.

  13. Identification and testing of oviposition attractant chemical compounds for Musca domestica.

    Science.gov (United States)

    Tang, Rui; Zhang, Feng; Kone, N'Golopé; Chen, Jing-Hua; Zhu, Fen; Han, Ri-Chou; Lei, Chao-Liang; Kenis, Marc; Huang, Ling-Qiao; Wang, Chen-Zhu

    2016-09-26

    Oviposition attractants for the house fly Musca domestica have been investigated using electrophysiological tests, behavioural assays and field tests. Volatiles were collected via head space absorption method from fermented wheat bran, fresh wheat bran, rearing substrate residue and house fly maggots. A Y-tube olfactometer assay showed that the odor of fermented wheat bran was a significant attractant for female house flies. Bioactive compounds from fermented wheat bran for house fly females were identified by electrophysiology and mass spectrophotometry and confirmed with standard chemicals. Four electrophysiologically active compounds including ethyl palmitate, ethyl linoleate, methyl linoleate, and linoleic acid were found at a proportion of 10:24:6:0.2. Functional imaging in the female antennal lobes revealed an overlapped active pattern for all chemicals. Further multiple-choice behavioural bioassays showed that these chemicals, as well as a mixture that mimicked the naturally occurring combination, increased the attractiveness of non-preferred rearing substrates of cotton and maize powder. Finally, a field demonstration test revealed that, by adding this mimic blend into a rearing substrate used to attract and breed house flies in West Africa, egg numbers laid by females were increased. These chemicals could be utilized to improve house fly production systems or considered for lure traps.

  14. Chemical characterisation of semi-volatile and aerosol compounds from the photooxidation of toluene and NOx

    Science.gov (United States)

    White, Stephen J.; Jamie, Ian M.; Angove, Dennys E.

    2014-02-01

    The chemical composition of a gas phase and secondary organic aerosol (SOA) mixture from toluene photooxidation in NOx was determined. Aerosol from toluene photooxidation was generated in a smog chamber and was collected onto glass fibre filters along with those gas phase compounds which adhered to the filter. The filter bound organic material was extracted, derivatised with O-2,3,4,5,6-pentafluorobenzyl hydroxylamine (PFBHA) and N,O-bistrimethylsilyl-trifluoroacetamide (BSTFA), then analysed using gas chromatography-mass spectrometry (GC-MS). Compound identification was aided by the use of isotopically-labelled toluene. The effect of humidity on product formation was investigated by raising water vapour concentration in one experiment. Sixty compounds were identified, of which twenty had not been identified from toluene photooxidation previously. Small carboxylic acids and dicarbonyls provided the highest proportion of identifiable compounds by relative response. The use of water to extract the filter samples resulted in much higher relative responses for oxocarboxylic acids, such as glyoxylic acid and pyruvic acid, than has been observed in previous studies. The formation of levulinic acid was determined to be due to the reaction of water with aromatic photooxidation products in the gas phase or particle phase of the chamber experiment. Nuclear magnetic resonance (NMR) was used to determine the functional groups of water-extracted organic material, which indicated that the water-soluble components were comprised of compounds which contain similar functional groups, primarily alcohols and carboxylic acids.

  15. Cationic and Anionic Disorder in CZTSSe Kesterite Compounds: A Chemical Crystallography Study.

    Science.gov (United States)

    Bais, Pierre; Caldes, Maria Teresa; Paris, Michaël; Guillot-Deudon, Catherine; Fertey, Pierre; Domengès, Bernadette; Lafond, Alain

    2017-10-02

    The cationic and anionic disorder in the Cu 2 ZnSnSe 4 -Cu 2 ZnSnS 4 (CZTSe-CZTS) system has been investigated through a chemical crystallography approach including X-ray diffraction (in conventional and resonant setup), 119 Sn and 77 Se NMR spectroscopy, and high-resolution transmission electron microscopy (HRTEM) techniques. Single-crystal XRD analysis demonstrates that the studied compounds behave as a solid solution with the kesterite crystal structure in the whole S/(S + Se) composition range. As previously reported for pure sulfide and pure selenide compounds, the 119 Sn NMR spectroscopy study gives clear evidence that the level of Cu/Zn disorder in mixed S/Se compounds depends on the thermal history of the samples (slow cooled or quenched). This conclusion is also supported by the investigation of the 77 Se NMR spectra. The resonant single-crystal XRD technique shows that regardless of the duration of annealing step below the order-disorder critical temperature the ordering is not a long-range phenomenon. Finally, for the very first time, HREM images of pure selenide and mixed S/Se crystals clearly show that these compounds have different microstructures. Indeed, only the mixed S/Se compound exhibits a mosaic-type contrast which could be the sign of short-range anionic order. Calculated images corroborate that HRTEM contrast is highly dependent on the nature of the anion as well as on the local anionic order.

  16. Chemical interaction in resistors based on lead ruthenite with additions of niobium(5) oxide compounds

    International Nuclear Information System (INIS)

    Lozinskij, N.S.; Shevtsova, N.A.; Gruba, A.I.; Volkov, V.I.

    1986-01-01

    The method of X-ray phase analysis was used to study chemical interaction in isothermal cross-section of Pb 2 RU 2 O 6 -Nb 2 O 5 , Rbsub(2)Rusub(2)Osub(6)-NbWOsub(5.5) and Rb 2 Ru 2 O 6 -Pb 2 Nb 2 O 7 systems at 850 deg C as well as in models of real ruthenium resistors. Chemical interaction is stated to take place in systems with niobium (5) oxide and NbWOsub(5.5). Niobium (5) and tungsten (6) displace ruthenium (4) from its compounds with formation of their lead salts. Similar chemical interactions between current-carrying phase of the resistor and modifiers representing niobium-containing take place in models of components of the studied systems take place in models of resistors

  17. Chemical and physical data for the actinide elements and their compounds

    International Nuclear Information System (INIS)

    Perry, D.L.

    1994-01-01

    The chemistry of the actinide elements, elements comprising the 5f block of elements in the Periodic Table, has become increasingly more important with respect to the environment. This is especially true regarding the need for an understanding of these elements and their reactions in the remediation of sites that have been previously used for nuclear materials production, processing, and fabrication. A detailed knowledge of the chemical and physical properties of these elements is also necessary for deriving rigorous codes and models for the chemical transport of the actinides in soils and groundwaters. This paper is centered around a discussion of the various data resources for the chemical and physical properties of actinides and actinide-based materials. The classes of actinides covered include oxides, sulfides, hydroxides, carbonates, salts, and the heavier chalcogenides. Additionally, data sources for actinide materials used in the nuclear (and other) industry are discussed, as are compounds of actinide elements

  18. Synthesis of reference compounds related to Chemical Weapons Convention for verification and drug development purposes – a Brazilian endeavour

    Science.gov (United States)

    Cavalcante, S. F. A.; de Paula, R. L.; Kitagawa, D. A. S.; Barcellos, M. C.; Simas, A. B. C.; Granjeiro, J. M.

    2018-03-01

    This paper deals with challenges that Brazilian Army Organic Synthesis Laboratory has been going through to access reference compounds related to the Chemical Weapons Convention in order to support verification analysis and for research of novel antidotes. Some synthetic procedures to produce the chemicals, as well as Quality Assurance issues and a brief introduction of international agreements banning chemical weapons are also presented.

  19. Ceramic/metal and A15/metal superconducting composite materials exploiting the superconducting proximity effect and method of making the same

    International Nuclear Information System (INIS)

    Holcomb, M.J.

    1999-01-01

    A composite superconducting material made of coated particles of ceramic superconducting material and a metal matrix material is disclosed. The metal matrix material fills the regions between the coated particles. The coating material is a material that is chemically nonreactive with the ceramic. Preferably, it is silver. The coating serves to chemically insulate the ceramic from the metal matrix material. The metal matrix material is a metal that is susceptible to the superconducting proximity effect. Preferably, it is a NbTi alloy. The metal matrix material is induced to become superconducting by the superconducting proximity effect when the temperature of the material goes below the critical temperature of the ceramic. The material has the improved mechanical properties of the metal matrix material. Preferably, the material consists of approximately 10% NbTi, 90% coated ceramic particles (by volume). Certain aspects of the material and method will depend upon the particular ceramic superconductor employed. An alternative embodiment of the invention utilizes A15 compound superconducting particles in a metal matrix material which is preferably a NbTi alloy

  20. Ceramic/metal and A15/metal superconducting composite materials exploiting the superconducting proximity effect and method of making the same

    Science.gov (United States)

    Holcomb, Matthew J.

    1999-01-01

    A composite superconducting material made of coated particles of ceramic superconducting material and a metal matrix material. The metal matrix material fills the regions between the coated particles. The coating material is a material that is chemically nonreactive with the ceramic. Preferably, it is silver. The coating serves to chemically insulate the ceramic from the metal matrix material. The metal matrix material is a metal that is susceptible to the superconducting proximity effect. Preferably, it is a NbTi alloy. The metal matrix material is induced to become superconducting by the superconducting proximity effect when the temperature of the material goes below the critical temperature of the ceramic. The material has the improved mechanical properties of the metal matrix material. Preferably, the material consists of approximately 10% NbTi, 90% coated ceramic particles (by volume). Certain aspects of the material and method will depend upon the particular ceramic superconductor employed. An alternative embodiment of the invention utilizes A15 compound superconducting particles in a metal matrix material which is preferably a NbTi alloy.

  1. Heat capacities and phase analysis of the superconductive compounds Mosub(6+y0) Se8 and Gdsub(x0) Mosub(6+y0) Se8

    International Nuclear Information System (INIS)

    Nerz, K.P.

    1979-02-01

    High precision heat capacity measurements were performed on a high quality sample of Mo 6 Se 8 . The values obtained for the Sommerfeld-constant γ, density of states N(Esub(F)) and entropy S 2 (Tsub(c)) of the electronic system are a factor 1.5 to 2 larger than have been published earlier by other groups. The differences are attributed to the lower concentration of impurity phases in our sample. Our sample of Mo 6 Se 8 shows a discontinuity in the electronic heat capacity at Tsub(c) with a relative height (Csub(es)-Csub(en))/Csub(en) which is a factor 1.6 larger compared to an ideal BCS-superconductor. The energy gap in the excitation spectrum of the superconductor Mo 6 Se 8 is a factor 1.4 wider than for an ideal BCS-superconductor in the observed temperature regime. Our data for the electronic heat capacity of the superconducting phase Mo 6 Se 8 are in good agreement with the calculated values corresponding to the 'strong coupling'-model of Padamsee et al. For the characteristic quantity of the electron-phonon interaction, lambda, a value of 0.8 was calculated. All these results support the conclusions that Mo 6 Se 8 behaves like a superconductor with a strong electron-phonon interaction. In addition heat capacity measurements have been made for samples of the ternary Chevrel-phase compounds 'Gdsub(x 0 )Mosub(6+y 0 )Se 8 ' which were prepared by a variety of methods. A quantitative analysis of impurity phases has been made from the heat capacity data. (orig.) [de

  2. Identification of chemical compounds in a liquid-liquid extraction system

    International Nuclear Information System (INIS)

    Ramirez C, F de M de la.

    1980-01-01

    The objective of the present work is to identify the chemical compounds that are distributed in a liquid-liquid extraction system in which the third phase is observed; for this purpose the FeCl 3 (0.12M) - HCl (8.43M) - Diisopropilic ether - system was used, for the quantitative determination of the chemical compounds, FeCl 3 solutions labelled with 59 Fe or witH 38 Cl were used; the Karl Fischer method for the determination of the water concentration at the organic phases was used, the obtained data was used for the calculations of the H + distribution in each phase. The results are that when the distribution equilibrium is reached, the aqueous phase is a 7.5M HCl solution; the light organic phase contains 2 H[FeCl 4 ].6H 2 O and the dense organic phase contains 2 H[FeCl 4 ].6H 2 O.3HCl.12H 2 O. The differences between these compounds are due to a high concentration of water and the HCl in the organic solvent. This causes a heterogeneous physic field, and then the third phase formation. (author)

  3. Characterization of volatile compounds, physico-chemical and sensory characteristics of smoked dry-cured ham.

    Science.gov (United States)

    Marušić Radovčić, Nives; Vidaček, Sanja; Janči, Tibor; Medić, Helga

    2016-11-01

    Volatile compounds from smoked dry-cured ham were isolated by using headspace-solid phase microextraction and gas chromatography-mass spectrometry (GC-MS). Samples of biceps femoris were also evaluated for sensory physical and chemical characteristics. Eighty seven volatile aroma compounds of smoked dry-cured ham were identified. Chemical groups identified were aldehydes (35.6%), phenols (34.3%), alcohols (13.8%), terpenes (6.4%), aromatic hydrocarbons (2.6%), alkanes (2.2%), ketones (2.2%), esters (1.7%) and acids (0.7%). Except volatile compounds derived from lipolysis and proteolysis the second most abundant constituents were phenols that originate from smoking phase of the production process. The most abundant phenols were: 4-methylphenol, 3-methylphenol, 2-metoxy-4-methylphenol, 2-methylphenol, 2,6-dimethoxyphenol and 4-ethyl-2 methoxyphenol. Principal components analysis showed that NaCl and ash content positively correlated with the salty taste while fat content was correlated to marbling. Water content and a w value were negatively correlated with hardness of dry-cured ham while phenols were positively corelated with smoky aroma. Due to the different volatile composition and pronounced smoky aroma, smoked dry-cured ham can be distinguished from other types of dry-cured hams.

  4. Unraveling the structure and chemical mechanisms of highly oxygenated intermediates in oxidation of organic compounds

    KAUST Repository

    Wang, Zhandong

    2017-11-28

    Decades of research on the autooxidation of organic compounds have provided fundamental and practical insights into these processes; however, the structure of many key autooxidation intermediates and the reactions leading to their formation still remain unclear. This work provides additional experimental evidence that highly oxygenated intermediates with one or more hydroperoxy groups are prevalent in the autooxidation of various oxygenated (e.g., alcohol, aldehyde, keto compounds, ether, and ester) and nonoxygenated (e.g., normal alkane, branched alkane, and cycloalkane) organic compounds. These findings improve our understanding of autooxidation reaction mechanisms that are routinely used to predict fuel ignition and oxidative stability of liquid hydrocarbons, while also providing insights relevant to the formation mechanisms of tropospheric aerosol building blocks. The direct observation of highly oxygenated intermediates for the autooxidation of alkanes at 500–600 K builds upon prior observations made in atmospheric conditions for the autooxidation of terpenes and other unsaturated hydrocarbons; it shows that highly oxygenated intermediates are stable at conditions above room temperature. These results further reveal that highly oxygenated intermediates are not only accessible by chemical activation but also by thermal activation. Theoretical calculations on H-atom migration reactions are presented to rationalize the relationship between the organic compound’s molecular structure (n-alkane, branched alkane, and cycloalkane) and its propensity to produce highly oxygenated intermediates via extensive autooxidation of hydroperoxyalkylperoxy radicals. Finally, detailed chemical kinetic simulations demonstrate the influence of these additional reaction pathways on the ignition of practical fuels.

  5. Superconductors for superconducting magnets

    Science.gov (United States)

    Larbalestier, David

    2011-03-01

    Even in 1913 Kamerlingh Onnes envisioned the use of superconductors to create powerful magnetic fields well beyond the capability provided by cooling normal metals with liquid helium. Only some ``bad places'' in his Hg and Pb wires seemed to impede his first attempts at this dream, one that he imagined would be resolved in a few weeks of effort. In fact, of course, resolution required another 50 years and development of both a true understanding of the difference between type I and type II superconductors and the discovery of compounds such as Nb 3 Sn that could remain superconducting to fields as high as 30 T. And then indeed, starting in the 1960s, Onnes's dreams were comfortably surpassed. In the last 45 years virtually all superconducting magnets have been made from just two Nb-base materials, Nb-Ti and Nb 3 Sn. Now it seems that a new generation of magnets based on cuprate high temperature superconductors with fields well above 30 T are possible using Bi-Sr-Ca-Cu-O and the RE-Ba-Cu-O compounds. We hope that a first demonstration of this possibility will be an all-superconducting 32 T magnet with RE-Ba-Cu-O insert that we are building for NHMFL users. The magnet application potential of this new generation of superconducting conductors will be discussed.

  6. Methods for chemical synthesis of biologically active compounds using supramolecular protective groups and novel compounds obtainable Thereby

    NARCIS (Netherlands)

    Herrmann, Andreas; Bastian, Andreas Alexander; Marcozzi, Alessio

    2014-01-01

    The invention relates to drug development and synthetic chemistry, in particular to the manufacture of biologically active compounds based on naturally occurring molecules. It also relates to novel biologically active compounds, for example aminoglycoside antibiotics, in a substantially pure

  7. Deciphering potential chemical compounds of gaseous oxidized mercury in Florida, USA

    Science.gov (United States)

    Huang, Jiaoyan; Miller, Matthieu B.; Edgerton, Eric; Sexauer Gustin, Mae

    2017-02-01

    The highest mercury (Hg) wet deposition in the United States of America (USA) occurs along the Gulf of Mexico, and in the southern and central Mississippi River Valley. Gaseous oxidized Hg (GOM) is thought to be a major contributor due to high water solubility and reactivity. Therefore, it is critical to understand concentrations, potential for wet and dry deposition, and GOM compounds present in the air. Concentrations and dry-deposition fluxes of GOM were measured and calculated for Naval Air Station Pensacola Outlying Landing Field (OLF) in Florida using data collected by a Tekran® 2537/1130/1135, the University of Nevada Reno Reactive Mercury Active System (UNRRMAS) with cation exchange and nylon membranes, and the Aerohead samplers that use cation-exchange membranes to determine dry deposition. Relationships with Tekran®-derived data must be interpreted with caution, since the GOM concentrations measured are biased low depending on the chemical compounds in air and interferences with water vapor and ozone.Criteria air pollutants were concurrently measured. This allowed for comparison and better understanding of GOM.In addition to other methods previously applied at OLF, use of the UNRRMAS provided a platform for determination of the chemical compounds of GOM in the air. Results from nylon membranes with thermal desorption analyses indicated seven GOM compounds in this area, including HgBr2, HgCl2, HgO, Hg-nitrogen and sulfur compounds, and two unknown compounds. This indicates that the site is influenced by different gaseous phase reactions and sources. Using back-trajectory analysis during a high-GOM event related to high CO, but average SO2, indicated air parcels moved from the free troposphere and across Arkansas, Mississippi, and Alabama at low elevation (pollutants and long-range transport.In order to develop methods to measure GOM concentrations and chemistry, and model dry-deposition processes, the actual GOM compounds need to be known, as well as

  8. Review physical and chemical aspects of stabilization of compounds in silk.

    Science.gov (United States)

    Pritchard, Eleanor M; Dennis, Patrick B; Omenetto, Fiorenzo; Naik, Rajesh R; Kaplan, David L

    2012-06-01

    The challenge of stabilization of small molecules and proteins has received considerable interest. The biological activity of small molecules can be lost as a consequence of chemical modifications, while protein activity may be lost due to chemical or structural degradation, such as a change in macromolecular conformation or aggregation. In these cases, stabilization is required to preserve therapeutic and bioactivity efficacy and safety. In addition to use in therapeutic applications, strategies to stabilize small molecules and proteins also have applications in industrial processes, diagnostics, and consumer products like food and cosmetics. Traditionally, therapeutic drug formulation efforts have focused on maintaining stability during product preparation and storage. However, with growing interest in the fields of encapsulation, tissue engineering, and controlled release drug delivery systems, new stabilization challenges are being addressed; the compounds or protein of interest must be stabilized during: (1) fabrication of the protein or small molecule-loaded carrier, (2) device storage, and (3) for the duration of intended release needs in vitro or in vivo. We review common mechanisms of compound degradation for small molecules and proteins during biomaterial preparation (including tissue engineering scaffolds and drug delivery systems), storage, and in vivo implantation. We also review the physical and chemical aspects of polymer-based stabilization approaches, with a particular focus on the stabilizing properties of silk fibroin biomaterials. Copyright © 2012 Wiley Periodicals, Inc.

  9. Effects of substrate temperature on growth orientation and superconducting properties of YBa2Cu3O7 - x films prepared by metalorganic chemical vapor deposition

    Science.gov (United States)

    Li, Y. Q.; Zhao, J.; Chern, C. S.; Gallois, B.; Norris, P.; Kear, B.

    1992-03-01

    The effects of substrate temperature on the structural and superconducting properties of YBa2Cu3O7-x films prepared by metalorganic chemical vapor deposition have been studied in the temperature range of 550 to 690 °C. Highly c-axis oriented films with transition temperatures of 90 K and critical current densities at 77.5 K and 0 T larger than 106 A/cm2 could be produced at substrate temperatures above 650 °C. As the temperature was decreased, the amount of a-axis orientation in the film increased. Films grown at a substrate temperature of 600 °C showed a strong a-axis orientation with a transition temperature of 83.5 K and a critical current density of 4.5×105 A/cm2 at 77.5 K and 0 T.

  10. Development of a fluorine-free chemical solution deposition route for rare-earth cuprate superconducting tapes and its application to reel-to-reel processing

    DEFF Research Database (Denmark)

    Tang, Xiao

    to Pulsed Laser Deposition (PLD) and Chemical Vapor Deposition (CVD), the trifluoroacetate metal-organic deposition (TFA-MOD) route is more promising for producing REBCO superconducting films, owing to the high-Jc, high reproducibility, and low cost of this technique, which doesn't require any high vacuum...... are classified into four categories, which are the barium fluoride process, barium hydroxide process, barium nitrate process, and barium carbonate process. In the aim of selecting the most suitable process for producing REBCO films in our research, trial experiments were also done to compare microstructure...... performance of the YBCO films, and the focus of chapter 4 was on the selection of chelating agents on the basis of the precursor solution stability. In Chapter 6, high-thermal -stability polymerized acrylic acid was used to suppress the grain growth of intermediate phases forming during and after pyrolysis...

  11. Organic superconductivity

    International Nuclear Information System (INIS)

    Jerome, D.

    1980-01-01

    We present the experimental evidences for the existence of a superconducting state in the Quasi One Dimensional organic conductor (TMTSF) 2 PF 6 . Superconductivity occuring at 1 K under 12 kbar is characterized by a zero resistance diamagnetic state. The anistropy of the upper critical field of this type II superconductor is consistent with the band structure anistropy. We present evidences for the existence of large superconducting precursor effects giving rise to a dominant paraconductive contribution below 40 K. We also discuss the anomalously large pressure dependence of T sb(s), which drops to 0.19 K under 24 kbar in terms of the current theories. (author)

  12. Characterization of chemical compounds for dosimetry of the radiation in industrial processes

    International Nuclear Information System (INIS)

    Galante, Ana Maria Sisti

    1999-01-01

    Different chemical compounds have been studied to optimize dosimetric systems in irradiation processes. In this study 2,3,5 Triphenyl -2H- Tetrazolium Chloride, Brilliant Cresyl Blue, Bromocresol Green and Potassium Nitrate were investigated for their merits or faults, for 60 Co gamma field, in order to verify if can be considered as dosimeters. Fricke solution was used as reference dosimeter to determine absorption dose rates at the gamma facilities.Only Bromocresol Green and Potassium Nitrate are recommended for dosimetry purposes since the main characteristics were achieved. The other two compounds could be used in dosimetry with changes in their formulation. Bromocresol Green and potassium Nitrate are reproducible and radiation sensitive for absorbed doses from 300 Gy to 150 kGy Bromocresol Green was used in liquid form and Potassium Nitrate was prepared in solid pellets form. Spectrophotometry in the visible region was used as the main detection technique, which allows relating optical absorption, before and after irradiation, with the absorbed dose. The maximum absorption wavelength for each compound was observed at 450-460nm for bromocresol Green and 546nm for Potassium Nitrate. Dose calibration curves are linear for both compounds in all dose intervals. When irradiated with accelerated electrons, with energies between o,9 MeV and 1,5MeV, optical absorption intensification, of about 2,6 times, was observed when comparing results for Potassium Nitrate, with those for gamma rays. All the evaluations are presented in this work. (author)

  13. Chemical Composition and Characteristic Odor Compounds in Essential Oil from Alismatis Rhizoma (Tubers of Alisma orientale).

    Science.gov (United States)

    Miyazawa, Mitsuo; Yoshinaga, Seiji; Kashima, Yusei; Nakahashi, Hiroshi; Hara, Nobuyuki; Nakagawa, Hiroki; Usami, Atsushi

    2016-01-01

    Chemical composition and potent odorants that contribute to the characteristic odor of essential oil from Alismatis Rhizoma (tubers of Alisma orientale) were investigated by gas chromatography-mass spectrometry (GC-MS), GC-olfactometry (GC-O), aroma extract dilution analysis (AEDA) and relative flavor activity (RFA) methods. Fifty components, representing 94.5% of the total oil, were identified. In this study, we newly identified thirty-nine compounds in the oil from tubers of A. orientale. The major constituents of the essential oil were khusinol (36.2%), δ-elemene (12.4%), germacron (4.1%), alismol (3.8%), β-elemene (3.1%), and α-bisabolol (1.9%). Through sensory analysis, sixteen aroma-active compounds were detected and the key contributing aroma-active compounds were δ-elemene (woody, flavor dilution (FD)-factor = 4, RFA = 0.3) β-elemene (spicy, FD = 5, RFA = 0.7), spathulenol (green, FD = 5, RFA = 1.0), γ-eudesmol (woody, FD = 6, RFA = 1.5), and γ-cadinol (woody, FD = 5, RFA = 1.0). These compounds are thought to contribute to the odor from tubers of A. orientale. These results imply that the essential oil from the tubers of A. orientale deserve further investigations in the phytochemical and medicinal fields.

  14. Cocktail of chemical compounds robustly promoting cell reprogramming protects liver against acute injury

    Directory of Open Access Journals (Sweden)

    Yuewen Tang

    2017-02-01

    Full Text Available Abstract Tissue damage induces cells into reprogramming-like cellular state, which contributes to tissue regeneration. However, whether factors promoting the cell reprogramming favor tissue regeneration remains elusive. Here we identified combination of small chemical compounds including drug cocktails robustly promoting in vitro cell reprogramming. We then administrated the drug cocktails to mice with acute liver injuries induced by partial hepatectomy or toxic treatment. Our results demonstrated that the drug cocktails which promoted cell reprogramming in vitro improved liver regeneration and hepatic function in vivo after acute injuries. The underlying mechanism could be that expression of pluripotent genes activated after injury is further upregulated by drug cocktails. Thus our study offers proof-of-concept evidence that cocktail of clinical compounds improving cell reprogramming favors tissue recovery after acute damages, which is an attractive strategy for regenerative purpose.

  15. [Emission characteristics and hazard assessment analysis of volatile organic compounds from chemical synthesis pharmaceutical industry].

    Science.gov (United States)

    Li, Yan; Wang, Zhe-Ming; Song, Shuang; Xu, Zhi-Rong; Xu, Ming-Zhu; Xu, Wei-Li

    2014-10-01

    In this study, volatile organic compounds (VOCs) released from chemical synthesis pharmaceutical industry in Taizhou, Zhejiang province were analyzed quantitatively and qualitatively. The total volatile organic compounds (TVOCs) was in the range of 14.9-308.6 mg · m(-3). Evaluation models of ozone formation potentials (OFP) and health risk assessment were adopted to preliminarily assess the environmental impact and health risk of VOCs. The results showed that the values of OFP of VOCs were in the range of 3.1-315.1 mg · m(-3), based on the maximum incremental reactivity, the main principal contribution was toluene, tetrahydrofuran (THF), acetic ether etc. The non-carcinogenic risk and the carcinogen risk fell in the ranges of 9.48 x 10(-7)-4.98 x 10(-4) a(-1) and 3.17 x 10(-5)- 6.33 x 10(-3). The principal contribution of VOCs was benzene, formaldehyde and methylene chloride.

  16. Cocktail of chemical compounds robustly promoting cell reprogramming protects liver against acute injury.

    Science.gov (United States)

    Tang, Yuewen; Cheng, Lin

    2017-04-01

    Tissue damage induces cells into reprogramming-like cellular state, which contributes to tissue regeneration. However, whether factors promoting the cell reprogramming favor tissue regeneration remains elusive. Here we identified combination of small chemical compounds including drug cocktails robustly promoting in vitro cell reprogramming. We then administrated the drug cocktails to mice with acute liver injuries induced by partial hepatectomy or toxic treatment. Our results demonstrated that the drug cocktails which promoted cell reprogramming in vitro improved liver regeneration and hepatic function in vivo after acute injuries. The underlying mechanism could be that expression of pluripotent genes activated after injury is further upregulated by drug cocktails. Thus our study offers proof-of-concept evidence that cocktail of clinical compounds improving cell reprogramming favors tissue recovery after acute damages, which is an attractive strategy for regenerative purpose.

  17. Passive sampling of selected endocrine disrupting compounds using polar organic chemical integrative samplers

    International Nuclear Information System (INIS)

    Arditsoglou, Anastasia; Voutsa, Dimitra

    2008-01-01

    Two types of polar organic chemical integrative samplers (pharmaceutical POCIS and pesticide POCIS) were examined for their sampling efficiency of selected endocrine disrupting compounds (EDCs). Laboratory-based calibration of POCISs was conducted by exposing them at high and low concentrations of 14 EDCs (4-alkyl-phenols, their ethoxylate oligomers, bisphenol A, selected estrogens and synthetic steroids) for different time periods. The kinetic studies showed an integrative uptake up to 28 days. The sampling rates for the individual compounds were obtained. The use of POCISs could result in an integrative approach to the quality status of the aquatic systems especially in the case of high variation of water concentrations of EDCs. The sampling efficiency of POCISs under various field conditions was assessed after their deployment in different aquatic environments. - Calibration and field performance of polar organic integrative samplers for monitoring EDCs in aquatic environments

  18. Psychoactive plants described in a Brazilian literary work and their chemical compounds.

    Science.gov (United States)

    Otsuka, Rafaela Denise; Lago, João Henrique Ghilardi; Rossi, Lucia; Galduróz, José Carlos Fernandes; Rodrigues, Eliana

    2010-09-01

    Ethnopharmacological research investigates the plants and other medicinal and toxic substances utilized by different traditional populations. One approach in this field is a literature search of the available publications on medicinal plants. The purpose of the current study was to select plants with psychoactive effects described in a Brazilian literary work written by Pio Correa in 1926. Those mentioned plants were classified in accordance with their indications for use as stimulants and depressors of the central nervous system. For the phytochemical study herein, we researched these species via a database search, and all the obtained information was compiled into a new database to analyze possible correlations between the chemical compounds and the psychoactive categories. Of the 813 plants searched in the literary work, 104 presented chemical data in the scientific periodicals consulted. Seventy-five of them belong to the stimulant category, while 31 are depressors and two of them belong to both categories. Phenols and flavonoids were the main compounds observed in plants of both categories, though at different frequencies. Monoterpenes (29.9%) and sesquiterpenes (28.6%) were also observed in plants from the stimulant category, while 25.8% of plants from the depressor category were comprised of carotenoids and 22.6% of steroids. The main specific compounds were identified as ferulic acid, α-pinene, limonene, α-humulene and kaempferol among the stimulant plants. Otherwise, in depressor plants were characterized caffeic acid, kaempferol, quercetin, β-carotene, physalins and withanolides as specific compounds. The association between ethnopharmacological and chemotaxonomic data, as presented in this study, could support plant selection in further investigations by research groups whose studies focus on psychoactive plants as potential therapeutics.

  19. Quantitative detection of chemical compounds in human hair with coherent anti-Stokes Raman scattering microscopy

    Science.gov (United States)

    Zimmerley, Maxwell; Lin, Chia-Yu; Oertel, David C.; Marsh, Jennifer M.; Ward, Jimmie L.; Potma, Eric Olaf

    2009-07-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is used to determine the distribution and concentration of selected compounds in intact human hair. By generating images based on ratiometric CARS contrast, quantitative concentration maps of both water and externally applied d-glycine are produced in the cortex of human hair fibers. Both water and d-glycine are found to homogeneously distribute throughout the cortical regions of the hair. The ability to selectively detect molecular agents in hair fibers is of direct relevance to understanding the chemical and physical mechanisms that underlie the performance of hair-care products.

  20. Chemical effects on the Kβ/Kα intensity ratios in first-row transition element compounds

    International Nuclear Information System (INIS)

    Kuecuekoender, A.; Buekuekkasap, E.; Yilmaz, R.; Sahin, Y.

    1999-01-01

    Chemical effects on the K β /K α X-ray intensity ratios for some first-row transition element compounds were studied experimentally and calculated. The vacancies in the K shell were created by 59.5 keV γ rays from an 241 Am radioactive source and characteristic X-ray radiation from sample was measured by using Si(Li) and Ge(Li) detectors. The calculations were carried out using Brunner's model. The calculated relative K β /K α X-ray intensity ratios are in good agreement with the present and the previously published experimental data. (author)

  1. Superconducting linac

    International Nuclear Information System (INIS)

    Bollinger, L.M.; Shepard, K.W.; Wangler, T.P.

    1978-01-01

    This project has two goals: to design, build, and test a small superconducting linac to serve as an energy booster for heavy ions from an FN tandem electrostatic accelerator, and to investigate various aspects of superconducting rf technology. The main design features of the booster are described, a status report on various components (resonators, rf control system, linac control system, cryostats, buncher) is given, and plans for the near future are outlined. Investigations of superconducting-linac technology concern studies on materials and fabrication techniques, resonator diagnostic techniques, rf-phase control, beam dynamics computer programs, asymmetry in accelerating field, and surface-treatment techniques. The overall layout of the to-be-proposed ATLAS, the Argonne Tandem-Linac Accelerator System, is shown; the ATLAS would use superconducting technology to produce beams of 5 to 25 MeV/A. 6 figures

  2. Superconducting materials

    International Nuclear Information System (INIS)

    Kormann, R.; Loiseau, R.; Marcilhac, B.

    1989-01-01

    The invention concerns superconducting ceramics containing essentially barium, calcium and copper fluorinated oxides with close offset and onset temperatures around 97 K and 100 K and containing neither Y nor rare earth [fr

  3. Molecular descriptor data explain market prices of a large commercial chemical compound library

    Science.gov (United States)

    Polanski, Jaroslaw; Kucia, Urszula; Duszkiewicz, Roksana; Kurczyk, Agata; Magdziarz, Tomasz; Gasteiger, Johann

    2016-06-01

    The relationship between the structure and a property of a chemical compound is an essential concept in chemistry guiding, for example, drug design. Actually, however, we need economic considerations to fully understand the fate of drugs on the market. We are performing here for the first time the exploration of quantitative structure-economy relationships (QSER) for a large dataset of a commercial building block library of over 2.2 million chemicals. This investigation provided molecular statistics that shows that on average what we are paying for is the quantity of matter. On the other side, the influence of synthetic availability scores is also revealed. Finally, we are buying substances by looking at the molecular graphs or molecular formulas. Thus, those molecules that have a higher number of atoms look more attractive and are, on average, also more expensive. Our study shows how data binning could be used as an informative method when analyzing big data in chemistry.

  4. Chemical constituents from red algae Bostrychia radicans (Rhodomelaceae): new amides and phenolic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Ana Ligia Leandrini de; Silva, Denise B. da; Lopes, Norberto P.; Debonsi, Hosana M. [Universidade de Sao Paulo (FCFRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Ciencias Farmaceuticas de Ribeirao Preto. Dept. de Quimica e Fisica; Yokoya, Nair S., E-mail: hosana@fcfrp.usp.br [Instituto de Botanica, Sao Paulo, SP (Brazil). Secao de Ficologia

    2012-07-01

    This study describes the isolation and structural determination of two amides, isolated for the first time: N,4-dihydroxy-N-(2'-hydroxyethyl)-benzamide (0.019%) and N,4-dihydroxy-N-(2'-hydroxyethyl)-benzeneacetamide (0.023%). These amides, produced by the red macroalgae Bostrychia radicans, had their structures assigned by NMR spectral data and MS analyses. In addition, this chemical study led to the isolation of cholesterol, heptadecane, squalene, trans-phytol, neophytadiene, tetradecanoic and hexadecanoic acids, methyl hexadecanoate and methyl 9-octadecenoate, 4-(methoxymethyl)-phenol, 4-hydroxybenzaldehyde, methyl 4-hydroxybenzeneacetate, methyl 2-hydroxy-3-(4-hydroxyphenyl)-propanoate, hydroquinone, methyl 4-hydroxymandelate, methyl 4-hydroxybenzoate, 4-hydroxybenzeneacetic acid and (4-hydroxyphenyl)-oxo-acetaldehyde. This is the first report concerning these compounds in B. radicans, contributing by illustrating the chemical diversity within the Rhodomelaceae family. (author)

  5. Structural changes and the nature of superconductivity in rare-earth doped CaFe2As2

    Science.gov (United States)

    Drye, Tyler

    Chemical substitution into iron-pnictide parent compounds (e.g. AFe2As2 where A=Ba, Sr, or Ca) has proven to be an effective means to induce bulk high-temperature superconductivity in these systems. By doping CaFe2As2 with rare-earth lanthanides (La, Ce, Pr, and Nd), we have observed a 47 K superconducting phase coexisting with a lattice distorting "collapse" transition. Both of these effects have important ramifications: the collapse transition occurs when interlayer As atoms form a bond, shrinking the c-axis lattice constant and simultaneously quenching the iron magnetic moment. This transition is further explored in context of a similar system, Sr-doped BaNi2As2. The superconducting phase, given the right combination of conditions, appears with a critical temperature as high as 49 K, but always in a very small volume of the sample (as determined by shielding effects). This has led to interesting theories about the nature of this superconductivity. A recently posited idea of "interfacial superconductivity" has been ruled out by our tests. Additionally, increasing the concentration of rare-earth atoms does not increase the superconducting volume fraction, but, in fact lowers the transition temperature, excluding the hypothesis that rare-earth defects are responsible for the minority superconducting phase. New pressure measurements have shown that the superconducting phase is stabilized when antiferromagnetic order is fully suppressed.

  6. Superconductivity: Phenomenology

    International Nuclear Information System (INIS)

    Falicov, L.M.

    1988-08-01

    This document discusses first the following topics: (a) The superconducting transition temperature; (b) Zero resistivity; (c) The Meissner effect; (d) The isotope effect; (e) Microwave and optical properties; and (f) The superconducting energy gap. Part II of this document investigates the Ginzburg-Landau equations by discussing: (a) The coherence length; (b) The penetration depth; (c) Flux quantization; (d) Magnetic-field dependence of the energy gap; (e) Quantum interference phenomena; and (f) The Josephson effect

  7. Modeling the Detection of Organic and Inorganic Compounds Using Iodide-Based Chemical Ionization.

    Science.gov (United States)

    Iyer, Siddharth; Lopez-Hilfiker, Felipe; Lee, Ben H; Thornton, Joel A; Kurtén, Theo

    2016-02-04

    Iodide-based chemical ionization mass spectrometry (CIMS) has been used to detect and measure concentrations of several atmospherically relevant organic and inorganic compounds. The significant electronegativity of iodide and the strong acidity of hydroiodic acid makes electron transfer and proton abstraction essentially negligible, and the soft nature of the adduct formation ionization technique reduces the chances of sample fragmentation. In addition, iodide has a large negative mass defect, which, when combined with the high resolving power of a high resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS), provides good selectivity. In this work, we use quantum chemical methods to calculate the binding energies, enthalpies and free energies for clusters of an iodide ion with a number of atmospherically relevant organic and inorganic compounds. Systematic configurational sampling of the free molecules and clusters was carried out at the B3LYP/6-31G* level, followed by subsequent calculations at the PBE/SDD and DLPNO-CCSD(T)/def2-QZVPP//PBE/aug-cc-pVTZ-PP levels. The binding energies, enthalpies, and free energies thus obtained were then compared to the iodide-based University of Washington HR-ToF-CIMS (UW-CIMS) instrument sensitivities for these molecules. We observed a reasonably linear relationship between the cluster binding enthalpies and logarithmic instrument sensitivities already at the PBE/SDD level, which indicates that relatively simple quantum chemical methods can predict the sensitivity of an iodide-based CIMS instrument toward most molecules. However, higher level calculations were needed to treat some outlier molecules, most notably oxalic acid and methylerythritol. Our calculations also corroborated the recent experimental findings that the molecules that the UW-CIMS detects at maximum sensitivity usually have binding enthalpies to iodide which are higher than about 26 kcal/mol, depending slightly on the level of theory.

  8. Identification and determination of chemical compounds of five aromatic waters from Iran

    Directory of Open Access Journals (Sweden)

    T. Hosseinabadi*

    2017-11-01

    Full Text Available Background and objectives: Herbal aromatic waters are one of the products used in the Iranian traditional medicine. These products have small amount of essential oil. The purpose of this study was to identify the effective substances of herbal aromatic waters by various techniques (GC/FID and GC/MS. It is hoped that with assessment of these compounds by mentioned techniques a suitable way could be found for standardization of the herbal aromatic waters. Methods: Four medicinal plants (Zataria multiflora, Fumaria parviflora, Rosa damascena, and Mentha spicata and aromatic water of Salix aegyptiaca were purchased from Tehran and their aromatic waters were extracted by hydrodistillation. In the next step, the essential oils of these aromatic waters were extracted by n-hexane and injected into GC/FID and GC/MS and chemical compounds were identified. Also, the standard components (thymol, carvone and 2-phenylethanol were injected to GC, separately and calibration curves were drawn. So, the content of the major components was calculated, carefully. Results: The results showed that the essential oil of F. parviflora contained more than 30 compounds. Its main compounds included carvacrol (16.7% and dihydroactinidiolide (13.8%. The essential oil of Salix aegyptiaca had 27 different compounds including 1,4-dimethoxybenzene (33.3% and heptacosane (28.1%. Z. multiflora, M. spicata and R. damascena essential oils contained thymol (0.065 mg/mL, carvone (0.01 mg/mL and 2-phenylethanol (0.015 mg/mL, as the main component, respectively. Conclusion: These results can be helpful for standardization and quality control of aromatic waters used in Iran.

  9. Analytical applications of oscillatory chemical reactions: determination of some pharmaceuticaly and biologically important compounds

    Directory of Open Access Journals (Sweden)

    Pejić Nataša D.

    2012-01-01

    Full Text Available Novel analytical methods for quantitive determination of analytes based on perturbations of oscillatory chemical reactions realized under open reactor conditions (continuosly fed well stirred tank reactor, CSTR, have been developed in the past twenty years. The proposed kinetic methods are generally based on the ability of the analyzed substances to change the kinetics of the chemical reactions matrix. The unambiguous correlation of quantitative characteristics of perturbations, and the amount (concentration of analyte expressed as a regression equation, or its graphics (calibration curve, enable the determination of the unknown analyte concentration. Attention is given to the development of these methods because of their simple experimental procedures, broad range of linear regression ( 10-7 10-4 mol L-1 and low limits of detection of analytes ( 10-6 10-8 mol L1, in some cases even lower than 10-12 mol L-1. Therefore, their application is very convenient for routine analysis of various inorganic and organic compounds as well as gases. This review summarizes progress made in the past 5 years on quantitative determination of pharmaceutically and biologically important compounds.

  10. Effects-driven chemical fractionation of heavy fuel oil to isolate compounds toxic to trout embryos.

    Science.gov (United States)

    Bornstein, Jason M; Adams, Julie; Hollebone, Bruce; King, Thomas; Hodson, Peter V; Brown, R Stephen

    2014-04-01

    Heavy fuel oil (HFO) spills account for approximately 60% of ship-source oil spills and are up to 50 times more toxic than medium and light crude oils. Heavy fuel oils contain elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) and alkyl-PAHs, known to be toxic to fish; however, little direct characterization of HFO toxicity has been reported. An effects-driven chemical fractionation was conducted on HFO 7102 to separate compounds with similar chemical and physical properties, including toxicity, to isolate the groups of compounds most toxic to trout embryos. After each separation, toxicity tests directed the next phase of fractionation, and gas chromatography-mass spectrometry analysis correlated composition with toxicity, with a focus on PAHs. Low-temperature vacuum distillation permitted the separation of HFO into 3 fractions based on boiling point ranges. The most toxic of these fractions underwent wax precipitation to remove long-chain n-alkanes. The remaining PAH-rich extract was further separated using open column chromatography, which provided distinct fractions that were grouped according to increasing aromatic ring count. The most toxic of these fractions was richest in PAHs and alkyl-PAHs. The results of the present study were consistent with previous crude oil studies that identified PAH-rich fractions as the most toxic. © 2013 SETAC.

  11. GC-MS analysis of chemical compounds from acetone extract of Echium amoenum Fisch.

    Directory of Open Access Journals (Sweden)

    M.J. Chaichi

    2017-11-01

    Full Text Available Background and objectives: Plants play a significant role in the prevention and treatment of diseases and can even prevent and reduce the adverse effects of conventional treatments.  Echium amoenum Fisch is one of the most commonly used medicinal plants, and has long been used as a traditional herbal medicine for many diseases in Iran. Gas chromatography-mass spectrometry (GC-MS method can be an interesting tool for testing the amount of some active principles in herbs used in cosmetic, drugs, pharmaceutical or food industries. Methods: The flowers of Echium amoenum Fisch were collected, washed, shade dried, powdered and extracted with acetone using Soxhlet apparatus. The extract were concentrated and analyzed by GC-MS for the identification of chemical compounds present in the flowers of Echium amoenum. Results: The major compounds were pentacosane, tricosan, 2-pentanone-4-hydroxy-4-methyl and 3-hexene-2-one. Conclusion: Identification of these compounds in the plant serves as the basis in determining the possible health benefits of the plant leading to further biologic and pharmacologic studies.

  12. ANALYSIS OF CHEMICAL COMPOUNDS OF AGARWOOD OIL FROM DIFFERENT SPECIES BY GAS CHROMATOGRAPHY MASS SPECTROMETRY (GCMS

    Directory of Open Access Journals (Sweden)

    Yumi Zuhanis Has-Yun Hashim

    2014-05-01

    Full Text Available ABSTRACT: Agarwood oil is a highly prized type of oil due to its unique aroma. The oil is extracted from the fragrant resin found in the agarwood tree (trunk.  The unique aroma and quality of agarwood resin and oil are contributed by the presence of certain chemical compounds. In this work, analysis and comparison of the chemical compounds of agarwood oil from A. malaccensis, A. sub-integra and a mixture of both were conducted.  The essential oils were diluted in hexane (5% prior to gas chromatography mass spectrometry (GCMS analysis performed using Agilent GCMS 7890A coupled with MSD quadrupole detector 5975 C.  Separation of analytes by gas chromatography was carried out using a Hewlett Packard HP-5MS silica capillary column (30 m X 0.25 mm X 0.25 mm. A total of 107 compounds were identified from the three samples of agarwood oils. Fifty-five (55 components were identified in A. malaccensis sample which contributes to the largest portion of the total compounds. About 20% of the compounds identified were aromatic and sesquiterpenes which have been revealed to be the main active compounds of agarwood oils which also give the aroma and pleasant odour of agarwood. Different compositions or profile of chemical components were found in agarwood oils from the two different species. Two compounds were commonly identified in all three samples namely 3-phenyl-2-butanone and alpha-cubebene.  Further studies are needed to refine the results which later can be used to assist detection and authentication of agarwood as well as its scientific-based grading. ABSTRAK: Minyak gaharu merupakan sejenis minyak beraroma unik yang mendapat permintaan tinggi dan mahal. Minyak ini diekstrak daripada resin beraroma yang terbentuk di dalam batang pokok gaharu. Keunikan aroma dan kualiti resin dan minyak gaharu ini bergantung kepada kehadiran bahan kimia tertentu. Penyelidikan ini menjurus kepada analisis dan perbandingan bahan-bahan kimia yang terdapat dalam minyak

  13. Emissions of chemical compounds and bioaerosols during the secondary treatment of paper mill effluents.

    Science.gov (United States)

    Goyer, N; Lavoie, J

    2001-01-01

    This study identified and quantified the main chemical compounds--the substances responsible for the disagreeable odors--and the bioaerosols emitted during the biological treatment of paper mill effluents. It also identified the characteristics of the process that effects the generation or diffusion of these substances. All treatment stages were evaluated. Measuring sites were located as closely as possible to the potential emission sources. Measurements were taken in the summer in 11 paper mills during a 2- to 3-day period in each mill. Chemical compounds were evaluated by direct-reading instruments; bioaerosols were sampled by impaction and counted. Sulfur compounds, emitted into the air when the effluent or the sludge is stirred, had the highest concentrations; their presence was attributable to such things as kraft-type paper pulp. Next in concentration were the carbon and nitrogen oxides, ammonia, and some organic acids, produced by the action of microorganisms. These acids are found mainly in the sludge environment. Terpenes, which come from wood, are present at various locations in paper mills. Odor perception thresholds for most of these substances are much lower than those established to protect the health of workers. Significant concentrations of total bacteria, total molds, and endotoxins were measured at several sites. Gram-negative bacteria were high at only one site, whereas the mold Aspergillus fumigatus was occasionally present at low concentration. No actinomycetes bacteria were detected. The highest concentrations were measured where there was water or dust aerosolization. Emissions are therefore controlled by controlling the operations that lead to the dispersion of water and particles into the air.

  14. Creating an Adaptive Technology Using a Cheminformatics System to Read Aloud Chemical Compound Names for People with Visual Disabilities

    Science.gov (United States)

    Kamijo, Haruo; Morii, Shingo; Yamaguchi, Wataru; Toyooka, Naoki; Tada-Umezaki, Masahito; Hirobayashi, Shigeki

    2016-01-01

    Various tactile methods, such as Braille, have been employed to enhance the recognition ability of chemical structures by individuals with visual disabilities. However, it is unknown whether reading aloud the names of chemical compounds would be effective in this regard. There are no systems currently available using an audio component to assist…

  15. Novel Data Mining Methods for Virtual Screening of Biological Active Chemical Compounds

    KAUST Repository

    Soufan, Othman M.

    2016-11-23

    Drug discovery is a process that takes many years and hundreds of millions of dollars to reveal a confident conclusion about a specific treatment. Part of this sophisticated process is based on preliminary investigations to suggest a set of chemical compounds as candidate drugs for the treatment. Computational resources have been playing a significant role in this part through a step known as virtual screening. From a data mining perspective, availability of rich data resources is key in training prediction models. Yet, the difficulties imposed by big expansion in data and its dimensionality are inevitable. In this thesis, I address the main challenges that come when data mining techniques are used for virtual screening. In order to achieve an efficient virtual screening using data mining, I start by addressing the problem of feature selection and provide analysis of best ways to describe a chemical compound for an enhanced screening performance. High-throughput screening (HTS) assays data used for virtual screening are characterized by a great class imbalance. To handle this problem of class imbalance, I suggest using a novel algorithm called DRAMOTE to narrow down promising candidate chemicals aimed at interaction with specific molecular targets before they are experimentally evaluated. Existing works are mostly proposed for small-scale virtual screening based on making use of few thousands of interactions. Thus, I propose enabling large-scale (or big) virtual screening through learning millions of interaction while exploiting any relevant dependency for a better accuracy. A novel solution called DRABAL that incorporates structure learning of a Bayesian Network as a step to model dependency between the HTS assays, is showed to achieve significant improvements over existing state-of-the-art approaches.

  16. Application of isotope-labelled compounds in the study of the chemical stability of pesticides

    International Nuclear Information System (INIS)

    Roesseler, M.; Luther, D.; Abendroth, H.C.; Koch, H.

    1980-01-01

    The user of pesticides requires specific biological modes of action from the corresponding commercial products. Impurities and degradation products may cause uncontrollable toxicological reactions. Profound knowledge of the chemical stability of the effective substance in question and its formulations under storage conditions as well as under those of analytical sample preparation and detection is required. Radioisotope labelled effective substances dimethoate and 1-butyl-amino-cyclohexane-phosphonic acid dibutyl ester are used to study storage stability of the pure effective substance and its formulations; effects of selected impurities, such as technical by-products, moisture or water content, binding or carrier materials, organic solvents, chemical stabilizers and other formulation components on storage properties; temperature dependence of storage stability; selection of suitable analytical techniques for quantitative determination of the effective substance without interference effects from any by-product; reduction of the necessary analytical expense; disclosure of sources of error in the application of usual analytical techniques; improvement of possibilities of an immediate and clearer discrimination between types and amounts of compounds in a chemical system consisting of one pesticide and its degradation or reaction products at the beginning and at the end of an experimental or reaction period. Radiochemical analytical techniques, such as radio thin-layer chromatography (also combined with liquid scintillation counting), radio gas chromatography, autoradiography and isotope dilution analysis were used. Results are discussed, especially of experiments on dimethoate and its technical by-products

  17. Sanitary Assessment of Hazardous Materials Exposed To Highly Toxic Chemical Compounds

    International Nuclear Information System (INIS)

    Rembovskiy, V.; Ermolaeva, E.

    2007-01-01

    -and-plant microflora and hydrocoles. 4. Development of non-standard methodical approaches when determining and interpreting the hazard classes of the wastes, containing high toxic compounds such as nerve gases. In particular, disembodied methods applied for solving the tasks of assessment of chemical compounds toxicity were summarized, as well as a uniform scheme of experimental toxicological assessment of TC of a high risk is presented. A system of quantitative assessment of the TC risk is developed on the basis of integral coefficient of risk (KTC), thus simplifying decision making after toxicological testing. Calculation of the coefficient of the TC risk is based on logarithm of ratio of toxicometry parameters to the value of identical parameters determining affiliation of the TC to the 1st class of risk (extreme risk). Due to the methodology developed in our Institute, we have for the first time estimated the class of toxicity of a highly complicated industrial system. (author)

  18. Toxicological and chemical assessment of ordnance compounds in marine sediments and porewaters

    Science.gov (United States)

    Nipper, M.; Carr, R.S.; Biedenbach, J.M.; Hooten, R.L.; Miller, K.

    2002-01-01

    Toxicological and chemical studies were performed with a silty and a sandy marine sediment spiked with 2,6-dinitrotoluene (2,6-DNT), 2,4,6-trinitrophenylmethylnitramine (tetryl), or 2,4,6-trinitrophenol (picric acid). Whole sediment toxicity was analyzed by the 10-day survival test with the amphipod Ampelisca abdita, and porewater toxicity tests assessed macro-algae (Ulva fasciata) zoospore germination and germling growth, sea urchin (Arbacia punctulata) embryological development, and polychaete (Dinophilus gyrociliatus) survival and reproduction. Whole sediments spiked with 2,6-DNT were not toxic to amphipods. The fine-grained sediment spiked with tetryl was also not acutely toxic. The tetryl and picric acid LC50 values in the sandy sediment were 3.24 and 144 mg/kg dry weight, respectively. The fine-grained sediment spiked with picric acid generated a U-shaped concentration-response curve in the amphipod test, with increased survival both in the lowest and highest concentration. Grain-size distribution and organic carbon content strongly influenced the behavior of ordnance compounds in spiked sediments. Very low concentrations were measured in some of the treatments and irreversible binding and biodegradation are suggested as the processes responsible for the low measurements. Porewater toxicity varied with its sedimentary origin and with ordnance compound. The sea urchin embryological development test tended to be the least sensitive. Tetryl was the most toxic chemical in all porewater tests, and picric acid the least toxic. Samples spiked with 2,6-DNT contained a degradation product identified as 2-methyl-3-nitroaniline (also known as 2-amino-6-nitrotoluene), and unidentified peaks, possibly degradation products, were also seen in some of the picric acid- and tetryl-spiked samples. Degradation products may have played a role in observed toxicity. ?? 2002 Elsevier Science Ltd. All rights reserved.

  19. Chemical composition, fatty acid profile and bioactive compounds of guava seeds (Psidium guajava L.

    Directory of Open Access Journals (Sweden)

    Ana Maria Athayde Uchôa-thomaz

    2014-09-01

    Full Text Available This study aimed to characterize the chemical composition, determine the fatty acid profile, and quantify the bioactive compounds present in guava seed powder (Psidium guajava L.. The powder resulted from seeds obtained from guava pulp processing. The agro-industrial seeds from red guava cv. paluma were used, and they were donated by a frozen pulp fruit manufacturer. They contain varying amounts of macronutrients and micronutrients, with a high content of total dietary fiber (63.94 g/100g, protein (11.19 g/100g, iron (13.8 mg/100g, zinc (3.31 mg/100g, and reduced calorie content (182 kcal/100g. Their lipid profile showed a predominance of unsaturated fatty acids (87.06%, especially linoleic acid (n6 and oleic acid (n9. The powder obtained contained significant amounts of bioactive compounds such as ascorbic acid (87.44 mg/100g, total carotenoids (1.25 mg/100 g and insoluble dietary fiber (63.55 g/100g. With regard to their microbiological quality, the samples were found suitable for consumption. Based on these results, it can be concluded that the powder produced has favorable attributes for industrial use, and that use of these seeds would be a viable alternative to prevent various diseases and malnutrition in our country and to reduce the environmental impact of agricultural waste.

  20. Superconductivity in metal-coated graphene

    Energy Technology Data Exchange (ETDEWEB)

    Calandra, Matteo; Mauri, Francesco [IMPMC, Universite Paris 6, CNRS, 4 Place Jussieu, 75005 Paris (France); Profeta, Gianni [SPIN-CNR - Dipartimento di Fisica Universita degli Studi di L' Aquila, 67100 L' Aquila (Italy)

    2012-12-15

    In this work we explore, by first-principles density functional theory (DFT) calculations, the possibility of inducing electron-phonon mediated superconductivity in a graphene sheet by doping its surface with alkaline metal adatoms. We demonstrate that, contrary to what could be naively believed, simple exfoliation to one layer of superconducting graphite intercalated compounds (GICs) does not necessarily lead to superconducting graphene, as it is the case in CaC{sub 6}. On the contrary, it is meaningful to look for superconductivity in monolayers obtained by exfoliating non-superconducting GICs. In particular, we demonstrate that Li coating and double-coating of graphene leads to superconductivity in graphene with T{sub c} that could be as large as 18 K. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Superconducting rotating electronic machine

    International Nuclear Information System (INIS)

    Cheon, Hui Yeong

    1989-04-01

    This book is divided into ten chapters, which handles summary of superconducting electronic machine, aspect of using of superconductor, superconducting direct current : Homopolar D. C. Machines, Drum machines, segmented slip-ring principle and carbon fibre brushes, superconducting alternating current turbine generator, design of superconducting alternating current machine, performance of superconducting alternating current machine, superconducting turbo generator by new rotor design, basic design of superconducting current generator, generator and power model, design of rotor and information of material property.

  2. Recent advances in fullerene superconductivity

    CERN Document Server

    Margadonna, S

    2002-01-01

    Superconducting transition temperatures in bulk chemically intercalated fulleride salts reach 33 K at ambient pressure and in hole-doped C sub 6 sub 0 derivatives in field-effect-transistor (FET) configurations, they reach 117 K. These advances pose important challenges for our understanding of high-temperature superconductivity in these highly correlated organic metals. Here we review the structures and properties of intercalated fullerides, paying particular attention to the correlation between superconductivity and interfullerene separation, orientational order/disorder, valence state, orbital degeneracy, low-symmetry distortions, and metal-C sub 6 sub 0 interactions. The metal-insulator transition at large interfullerene separations is discussed in detail. An overview is also given of the exploding field of gate-induced superconductivity of fullerenes in FET electronic devices.

  3. Molecular Mobility of an Amorphous Chiral Pharmaceutical Compound: Impact of Chirality and Chemical Purity.

    Science.gov (United States)

    Viel, Quentin; Delbreilh, Laurent; Coquerel, Gérard; Petit, Samuel; Dargent, Eric

    2017-08-17

    A dielectric relaxation spectroscopy (DRS) study was performed to investigate the molecular mobility of amorphous chiral diprophylline (DPL). For this purpose, both racemic DPL and a single enantiomer of DPL were considered. After fast cooling from the melt at very low temperature (-140 °C), progressive heating below and above the glass transition (T g ≈ 37 °C) induces two secondary relaxations (γ- and δ-) and primary relaxations (α-) for both enantiomeric compositions. After chemical purification of our samples by means of cooling recrystallization, no γ-process could be detected by DRS. Hence, it was highlighted that the molecular mobility in the glassy state is influenced by the presence of theophylline (TPH), the main impurity in DPL samples. We also proved that the dynamic behavior of a single enantiomer and the racemic mixture of the same purified compound are quasi-identical. This study demonstrates that the relative stability and the molecular mobility of chiral amorphous drugs are strongly sensitive to chemical purity.

  4. Development of a Wireless and Passive SAW-Based Chemical Sensor for Organophosphorous Compound Detection

    Directory of Open Access Journals (Sweden)

    Fang-Qian Xu

    2015-12-01

    Full Text Available A new wireless and passive surface acoustic wave (SAW-based chemical sensor for organophosphorous compound (OC detection is presented. A 434 MHz reflective delay line configuration composed by single phase unidirectional transducers (SPUDTs and three shorted reflectors was fabricated on YZ LiNbO3 piezoelectric substrate as the sensor element. A thin fluoroalcoholpolysiloxane (SXFA film acted as the sensitive interface deposited onto the SAW propagation path between the second and last reflectors of the SAW device. The first reflector was used for the temperature compensation utilizing the difference method. The adsorption between the SXFA and OC molecules modulates the SAW propagation, especially for the time delay of the SAW, hence, the phase shifts of the reflection peaks from the corresponding reflectors can be used to characterize the target OC. Prior to the sensor fabrication, the coupling of modes (COM and perturbation theory were utilized to predict the SAW device performance and the gas adsorption. Referring to a frequency-modulated continuous wave (FMCW-based reader unit, the developed SAW chemical sensor was wirelessly characterized in gas exposure experiments for dimethylmethylphosphonate (DMMP detection. Sensor performance parameters such as phase sensitivity, repeatability, linearity, and temperature compensation were evaluated experimentally.

  5. Coexistence of magnetism and superconductivity in the iron-based compound Cs0.8(FeSe0.98)2.

    Science.gov (United States)

    Shermadini, Z; Krzton-Maziopa, A; Bendele, M; Khasanov, R; Luetkens, H; Conder, K; Pomjakushina, E; Weyeneth, S; Pomjakushin, V; Bossen, O; Amato, A

    2011-03-18

    We report on muon-spin rotation and relaxation (μSR), electrical resistivity, magnetization and differential scanning calorimetry measurements performed on a high-quality single crystal of Cs(0.8)(FeSe(0.98))(2). Whereas our transport and magnetization data confirm the bulk character of the superconducting state below T(c)=29.6(2)  K, the μSR data indicate that the system is magnetic below T(N)=478.5(3)  K, where a first-order transition occurs. The first-order character of the magnetic transition is confirmed by differential scanning calorimetry data. Taken all together, these data indicate in Cs(0.8)(FeSe(0.98))(2) a microscopic coexistence between the superconducting phase and a strong magnetic phase. The observed T(N) is the highest reported to date for a magnetic superconductor.

  6. Superconducting transistor

    International Nuclear Information System (INIS)

    Gray, K.E.

    1978-01-01

    A three film superconducting tunneling device, analogous to a semiconductor transistor, is presented, including a theoretical description and experimental results showing a current gain of four. Much larger current gains are shown to be feasible. Such a development is particularly interesting because of its novelty and the striking analogies with the semiconductor junction transistor

  7. Superconducting materials

    International Nuclear Information System (INIS)

    Ruvalds, J.

    1990-01-01

    This report discusses the following topics: Fermi liquid nesting in high temperature superconductors; optical properties of high temperature superconductors; Hall effect in superconducting La 2-x Sr x CuO 4 ; source of high transition temperatures; and prospects for new superconductors

  8. Superconducting magnets

    International Nuclear Information System (INIS)

    1994-08-01

    This report discusses the following topics on superconducting magnets: D19B and -C: The next steps for a record-setting magnet; D20: The push beyond 10 T: Beyond D20: Speculations on the 16-T regime; other advanced magnets for accelerators; spinoff applications; APC materials development; cable and cabling-machine development; and high-T c superconductor at low temperature

  9. Bipolar superconductivity

    International Nuclear Information System (INIS)

    Pankratov, S.G.

    1987-01-01

    A model of bipolaron superconductivity suggested by Soviet scientist Alexandrov A.S. and French scientist Ranninger is presentes in a popular way. It is noted that the bipolaron theory gives a good explanation of certain properties of new superconductors, high critical temperature, in particular

  10. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    Energy Technology Data Exchange (ETDEWEB)

    Apel, Eric; Emmons, L.; Karl, Thomas G.; Flocke, Frank M.; Hills, A. J.; Madronich, Sasha; Lee-Taylor, J.; Fried, Alan; Weibring, P.; Walega, J.; Richter, Dirk; Tie, X.; Mauldin, L.; Campos, Teresa; Weinheimer, Andrew J.; Knapp, David; Sive, B.; Kleinman, Lawrence I.; Springston, S.; Zaveri, Rahul A.; Ortega, John V.; Voss, Paul B.; Blake, D. R.; Baker, Angela K.; Warneke, Carsten; Welsh-Bon, Daniel; de Gouw, Joost A.; Zheng, J.; Zhang, Renyi; Rudolph, Jochen; Junkermann, W.; Riemer, D.

    2010-01-01

    The volatile organic compound (VOC) distribution in the Mexico City Metropolitan Area (MCMA) and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs) but with a substantial contribution from oxygenated volatile organic compounds (OVOCs), predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry) model and MOZART (Model for Ozone and Related chemical Tracers) were able to reproduce the general features of the daytime cycle of the VOC OH reactivity distribution showing that NMHCs dominate the distribution except in the afternoon hours and that the VOC OH reactivity peaks in the early morning due to high morning emissions from the city into a shallow boundary layer. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height. In addition, a plume was studied in which air was advected out of the MCMA and intercepted downwind with the DOE G1 on March 18 and the NCAR C130 one day later on March 19. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind. Ozone and many OVOCs were photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial and temporal extent of the March 19 plume and to help interpret the OH

  11. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    Energy Technology Data Exchange (ETDEWEB)

    Apel, E.; Springston, S.; Karl, T.; Emmons, L.; Flocke, F.; Hills, A. J.; Madronich, S.; Lee-Taylor, J.; Fried, A.; Weibring, P.; Walega, J.; Richter, D., Tie, X.; Mauldin, L.; Campos, T.; Sive, B.; Kleinman, L.; Springston, S., Zaveri, R.; deGouw, J.; Zheng, J.; Zhang, R.; Rudolph, J.; Junkermann, W.; Riemer, D. D.

    2009-11-01

    The volatile organic compound (VOC) distribution in the Mexico City Metropolitan Area (MCMA) and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs) but with a substantial contribution from oxygenated volatile organic compounds (OVOCs), predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry) model and MOZART (Model for Ozone and Related chemical Tracers) were able to reproduce the general features of the daytime cycle of the VOC OH reactivity distribution showing that NMHCs dominate the distribution except in the afternoon hours and that the VOC OH reactivity peaks in the early morning due to high morning emissions from the city into a shallow boundary layer. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height. In addition, a plume was studied in which air was advected out of the MCMA and intercepted downwind with the DOE G1 on 18 March and the NCAR C130 one day later on 19 March. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind. Ozone and many OVOCs were photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial and temporal extent of the 19 March plume and to help interpret the OH

  12. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    Directory of Open Access Journals (Sweden)

    E. C. Apel

    2010-03-01

    Full Text Available The volatile organic compound (VOC distribution in the Mexico City Metropolitan Area (MCMA and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs but with a substantial contribution from oxygenated volatile organic compounds (OVOCs, predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry model and MOZART (Model for Ozone and Related chemical Tracers were able to approximate the observed MCMA daytime patterns and absolute values of the VOC OH reactivity. The MOZART model is also in agreement with observations showing that NMHCs dominate the reactivity distribution except in the afternoon hours. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height.

    A northeast transport event was studied in which air originating in the MCMA was intercepted aloft with the Department of Energy (DOE G1 on 18 March and downwind with the National Center for Atmospheric Research (NCAR C130 one day later on 19 March. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind; ozone was shown to be photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial extent and temporal evolution of the plume

  13. Endohedral gallide cluster superconductors and superconductivity in ReGa5

    Science.gov (United States)

    Xie, Weiwei; Luo, Huixia; Phelan, Brendan F.; Klimczuk, Tomasz; Cevallos, Francois Alexandre; Cava, Robert Joseph

    2015-01-01

    We present transition metal-embedded (T@Gan) endohedral Ga-clusters as a favorable structural motif for superconductivity and develop empirical, molecule-based, electron counting rules that govern the hierarchical architectures that the clusters assume in binary phases. Among the binary T@Gan endohedral cluster systems, Mo8Ga41, Mo6Ga31, Rh2Ga9, and Ir2Ga9 are all previously known superconductors. The well-known exotic superconductor PuCoGa5 and related phases are also members of this endohedral gallide cluster family. We show that electron-deficient compounds like Mo8Ga41 prefer architectures with vertex-sharing gallium clusters, whereas electron-rich compounds, like PdGa5, prefer edge-sharing cluster architectures. The superconducting transition temperatures are highest for the electron-poor, corner-sharing architectures. Based on this analysis, the previously unknown endohedral cluster compound ReGa5 is postulated to exist at an intermediate electron count and a mix of corner sharing and edge sharing cluster architectures. The empirical prediction is shown to be correct and leads to the discovery of superconductivity in ReGa5. The Fermi levels for endohedral gallide cluster compounds are located in deep pseudogaps in the electronic densities of states, an important factor in determining their chemical stability, while at the same time limiting their superconducting transition temperatures. PMID:26644566

  14. Moessbauer study of superconducting NdFeAsO{sub 0.88}F{sub 0.12} and its parent compound NdFeAsO

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, D R [Instituto de Fisica, Universidade Federal Fluminense, Avenida Milton Tavares de Souza, s/n-Campus da Praia Vermelha, 24210-346 Niteroi, RJ (Brazil); Alzamora, M; Munevar, J; Baggio-Saitovitch, E [Centro Brasileiro de Pesquisas Fisicas, Rua Xavier Sigaud 150, Urca 22290-180, Rio de Janeiro, RJ (Brazil); Wang, N L; Cheng, G F, E-mail: dalber@if.uff.b [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

    2009-11-11

    {sup 57}Fe Moessbauer spectroscopy has been used to investigate the magnetic order of non-superconducting NdFeAsO (T{sub N} = 140 K) and superconducting NdFeAsO{sub 0.88}F{sub 0.12} (T{sub c} = 45 K). A magnetic hyperfine field B{sub hf} was observed at the {sup 57}Fe nucleus below T{sub N}approx140 K for NdFeAsO. Below approx2 K an increase of B{sub hf} relative to the saturation value was attributed to the transferred B{sub hf} at the Fe site resulting from the collinear antiferromagnetic (AF) spin structure of the Nd moments. The analysis of the spectra is consistent with a commensurate AF order of Fe spins. No B{sub hf} is observed in superconducting NdFeAsO{sub 0.88}F{sub 0.12} down to 1.5 K.

  15. Magnetic and superconductive property study of the compounds: HoMo6S8, EuMo6S8 and Ce Mo6S8

    International Nuclear Information System (INIS)

    Dinia, M.A.

    1987-07-01

    Magnetic measurements and neutron spectroscopy measurements allowed to conclude that HoMo 6 S 8 was an Ising system. Neutron diffraction experiments and electric conductivity measurements simultaneously on a HoMo 6 S 8 monocrystal allowed to set that at null field superconductivity exists not only with the modulated magnetic structure but also with an antiphase magnetic structure (in a narrow temperature range). Superconductivity disparition at low temperature is then not related to the magnetic transition but to the development of magnetic moments of Ho 3+ ions. Superconducting phase got at low temperature by heating a monodomain ferromagnetic crystal is associated to a reduction of the ordered moment of Ho 3+ ions, because of an important demagnetizing field. At last, magnetic order evolution study in relation to the magnetic field allowed to precise the phase diagram of HoMo 6 S 8 . A crystal structure study of EuMo 6 S 8 in the high temperature rhomboedric phase and the low temperature triclinic phase were realized by neutron diffraction. Magnetic order in EuMo 6 S 8 below T N = 0.3K was determined [fr

  16. Safety in the Chemical Laboratory: Nitric Acid, Nitrates, and Nitro Compounds.

    Science.gov (United States)

    Bretherick, Leslie

    1989-01-01

    Discussed are the potential hazards associated with nitric acid, inorganic and organic nitrate salts, alkyl nitrates, acyl nitrates, aliphatic nitro compounds, aromatic nitro compounds, and nitration reactions. (CW)

  17. Dependence of the extraction capacity of neutral bidentate organophosphorus compounds on their structure: a quantum chemical study

    International Nuclear Information System (INIS)

    Sudarushkin, S.K.; Morgalyuk, V.P.; Tananaev, I.G.; Gribov, L.A.; Myasoedov, B.F.

    2006-01-01

    Correlations between the extraction capacities and molecular structures of organic phosphorus compounds (reagents for extraction of transplutonium elements from spent nuclear fuel) were studied using a quantum chemical approach. The results of calculations are in qualitative agreement with experimental data. The approach proposed can be used for analysis of the extraction properties of all classes of organic phosphorus compounds and also for prediction of the most efficient organic phosphorus extractants with preset properties [ru

  18. Currently Commercially Available Chemical Sensors Employed for Detection of Volatile Organic Compounds in Outdoor and Indoor Air

    OpenAIRE

    Bartosz Szulczyński; Jacek Gębicki

    2017-01-01

    The paper presents principle of operation and design of the most popular chemical sensors for measurement of volatile organic compounds (VOCs) in outdoor and indoor air. It describes the sensors for evaluation of explosion risk including pellistors and IR-absorption sensors as well as the sensors for detection of toxic compounds such as electrochemical (amperometric), photoionization and semiconductor with solid electrolyte ones. Commercially available sensors for detection of VOCs and their ...

  19. Organometallic chemical vapor deposition of superconducting, high T sub c Pb-doped Bi-Sr-Ca-Cu-O thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J.M.; Marcy, H.O.; Tonge, L.M.; Wessels, B.W.; Marks, T.J.; Kannewurf, C.R. (Northwestern University, Evanston, Illinois 60208 (US))

    1989-10-30

    Highly oriented films of the high {ital T}{sub {ital c}} Bi-Pb-Sr-Ca-Cu-O (BPSCCO)superconductor have been prepared by two organometallic chemical vapor deposition (OMCVD) approaches. In the first approach, Pb is introduced by alternate deposition of BSCCO and PbO{sub {ital x}} films using the volatile metalorganic precursors Cu(acetyl acetonate){sub 2}, Sr(dipivaloyl methanate){sub 2}, Ca(dipivaloyl methanate){sub 2}, triphenyl bismuth, and tetraphenyl lead. In the second approach, Pb is incorporated into an OMCVD-derived BSCCO film by vapor diffusion using PbO as the source. X-ray diffractometry and scanning electron microscopy reveal that Pb doping significantly improves the crystalline orientation and the film morphology. Films deposited by both methods on (100) single-crystal MgO consist predominantly of the Bi{sub 2}(Sr,Ca){sub 3}Cu{sub 2}O{sub {ital x}} phase and have a high preferential orientation of the crystallite {ital c} axes perpendicular to the substrate surface. Four-probe resistivity measurements indicate the onset of film superconductivity at {similar to}110 K and zero resistance by 80 K.

  20. Influence of Zr and Ce doping on electromagnetic properties of (Gd,Y)-Ba-Cu-O superconducting tapes fabricated by metal organic chemical vapor deposition

    International Nuclear Information System (INIS)

    Selvamanickam, V.; Chen, Y.; Xie, J.; Zhang, Y.; Guevara, A.; Kesgin, I.; Majkic, G.; Martchevsky, M.

    2009-01-01

    (Gd,Y)Ba 2 Cu 3 O x tapes have been fabricated by metal organic chemical vapor deposition (MOCVD) with Zr-doping levels of 0-15 mol.% and Ce doping levels of 0-10 mol.% in 0.4 μm thick films. The critical current density (J c ) of Zr-doped samples at 77 K, 1 T applied in the orientation of H -parallel c is found to increase with Zr content and shows a maximum at 7.5% Zr doping. The 7.5% Zr-doped sample exhibits a critical current density (J c ) of 0.95 MA/cm 2 at H -parallel c which is more than 70% higher than the J c of the undoped sample. The peak in J c at H -parallel c is 83% of that at H -parallel a-b in the 7.5% Zr-doped sample which is more than twice as that in the undoped sample. Superconducting transition temperature (T c ) values as high as about 89 K have been achieved in samples even with 15% Zr and 10% Ce. Ce-doped samples with and without Ba compensation are found to exhibit substantially different J c values as well as angular dependence characteristics.

  1. Influence of Zr and Ce doping on electromagnetic properties of (Gd,Y)-Ba-Cu-O superconducting tapes fabricated by metal organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Selvamanickam, V., E-mail: selva@uh.ed [Department of Mechanical Engineering and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Rd., Houston, TX 77204-4006 (United States); Chen, Y.; Xie, J. [SuperPower Inc., 450 Duane Ave., Schenectady, NY 12304 (United States); Zhang, Y.; Guevara, A.; Kesgin, I.; Majkic, G. [Department of Mechanical Engineering and Texas Center for Superconductivity, University of Houston, 4800 Calhoun Rd., Houston, TX 77204-4006 (United States); Martchevsky, M. [SuperPower Inc., 450 Duane Ave., Schenectady, NY 12304 (United States)

    2009-12-01

    (Gd,Y)Ba{sub 2}Cu{sub 3}O{sub x} tapes have been fabricated by metal organic chemical vapor deposition (MOCVD) with Zr-doping levels of 0-15 mol.% and Ce doping levels of 0-10 mol.% in 0.4 mum thick films. The critical current density (J{sub c}) of Zr-doped samples at 77 K, 1 T applied in the orientation of H -parallel c is found to increase with Zr content and shows a maximum at 7.5% Zr doping. The 7.5% Zr-doped sample exhibits a critical current density (J{sub c}) of 0.95 MA/cm{sup 2} at H -parallel c which is more than 70% higher than the J{sub c} of the undoped sample. The peak in J{sub c} at H -parallel c is 83% of that at H -parallel a-b in the 7.5% Zr-doped sample which is more than twice as that in the undoped sample. Superconducting transition temperature (T{sub c}) values as high as about 89 K have been achieved in samples even with 15% Zr and 10% Ce. Ce-doped samples with and without Ba compensation are found to exhibit substantially different J{sub c} values as well as angular dependence characteristics.

  2. Evaluating the correlation between chemical and sensory compounds in Blaufränkisch and Cabernet Franc wines

    Directory of Open Access Journals (Sweden)

    Irina Balga

    2014-12-01

    Full Text Available The positive physiological effects of the bioactive compounds of red wines have been known for a long time. Besides that, the polyphenolic compounds of red wines represent one of the most important factors for oenology. With a special chemical analysis, we discover the relationship between chemical and sensory compounds. In this way, we explore which compounds influence sensory properties. The phenolic compounds are the quality attributes of the wine. The analysis of phenolic compounds was carried out in two red wines: Cabernet Franc and Blaufränkisch. The aim of this study was to analyse the chemical and organoleptic characteristics of these two wines and evaluate the connection between the two parameters. In addition, we also examined the influence of the polyphenolic content on sensory perception. The experiment was carried out in a cool climate wine region in Eger, Hungary, in vintage of 2008. We investigated the profile of phenolic contents in new and aged wines. Total polyphenolic content, anthocyanin, leucoanthocyanin and catechin were evaluated by spectrophotometer. Stilbenes were identified and quantified by high-performance liquid chromatography.

  3. Physical basis of the effect of hemoglobin on the 31P NMR chemical shifts of various phosphoryl compounds

    International Nuclear Information System (INIS)

    Kirk, K.; Kuchel, P.W.

    1988-01-01

    The marked difference between the intra- and extracellular 31 P NMR chemical shifts of various phosphoryl compounds when added to a red cell suspension may be largely understood in terms of the effects of hemoglobin on the 31 P NMR chemical shifts. The presence of [oxy- or (carbonmonoxy)-] hemoglobin inside the red cell causes the bulk magnetic susceptibility of the cell cytoplasm to be significantly less than that of the external solution. This difference is sufficient to account for the difference in the intra- and extracellular chemical shifts of the two phosphate esters trimethyl phosphate and triethyl phosphate. However, in the case of the compounds dimethyl methylphosphonate, diethyl methylphosphonate, and trimethylphosphine oxide as well as the hypophosphite, phenylphosphinate, and diphenylphosphinate ions, hemoglobin exerts an additional, much larger, effect, causing the 31 P NMR resonances to shift to lower frequency in a manner that cannot be accounted for in terms of magnetic susceptibility. Lysozyme is a protein structurally unrelated to hemoglobin and was shown to cause similar shifts to lower frequency of the resonances of these six compounds; this suggests that the mechanism may involve a property of proteins in general and not a specific property of hemoglobin. The effect of different solvents on the chemical shifts of the eight phosphoryl compounds provided an insight into the possible physical basis of the effect. It is proposed that, in addition to magnetic susceptibility effects, hemoglobin exerts its influence on phosphoryl chemical shifts by disrupting the hydrogen bonding of the phosphoryl group to solvent water

  4. Electrocatalytic processing of renewable biomass-derived compounds for production of chemicals, fuels and electricity

    Science.gov (United States)

    Xin, Le

    The dual problems of sustaining the fast growth of human society and preserving the environment for future generations urge us to shift our focus from exploiting fossil oils to researching and developing more affordable, reliable and clean energy sources. Human beings had a long history that depended on meeting our energy demands with plant biomass, and the modern biorefinery technologies realize the effective conversion of biomass to production of transportation fuels, bulk and fine chemicals so to alleviate our reliance on fossil fuel resources of declining supply. With the aim of replacing as much non-renewable carbon from fossil oils with renewable carbon from biomass as possible, innovative R&D activities must strive to enhance the current biorefinery process and secure our energy future. Much of my Ph.D. research effort is centered on the study of electrocatalytic conversion of biomass-derived compounds to produce value-added chemicals, biofuels and electrical energy on model electrocatalysts in AEM/PEM-based continuous flow electrolysis cell and fuel cell reactors. High electricity generation performance was obtained when glycerol or crude glycerol was employed as fuels in AEMFCs. The study on selective electrocatalytic oxidation of glycerol shows an electrode potential-regulated product distribution where tartronate and mesoxalate can be selectively produced with electrode potential switch. This finding then led to the development of AEMFCs with selective production of valuable tartronate or mesoxalate with high selectivity and yield and cogeneration of electricity. Reaction mechanisms of electrocatalytic oxidation of ethylene glycol and 1,2-propanediol were further elucidated by means of an on-line sample collection technique and DFT modeling. Besides electro-oxidation of biorenewable alcohols to chemicals and electricity, electrocatalytic reduction of keto acids (e.g. levulinic acid) was also studied for upgrading biomass-based feedstock to biofuels while

  5. Microstructural and superconducting properties of high current metal-organic chemical vapor deposition YBa2Cu3O7-δ coated conductor wires

    International Nuclear Information System (INIS)

    Holesinger, T G; Maiorov, B; Ugurlu, O; Civale, L; Chen, Y; Xiong, X; Xie, Y; Selvamanickam, V

    2009-01-01

    Metal-organic chemical vapor deposition (MOCVD) on flexible, ion beam assisted deposition MgO templates has been used to produce high critical current density (J c ) (Y,Sm) 1 Ba 2 Cu 3 O y (REBCO) films suitable for use in producing practical high temperature superconducting (HTS) coated conductor wires. Thick films on tape were produced with sequential additions of 0.7 μm of REBCO via a reel-to-reel progression through a custom-designed MOCVD reactor. Multi-pass processing for thick film deposition is critically dependent upon minimizing surface secondary phase formation. Critical currents (I c s) of up to 600 A/cm width (t = 2.8 μm, J c = 2.6 MA cm -2 , 77 K, self-field) were obtained in short lengths of HTS wires. These high performance MOCVD films are characterized by closely spaced (Y,Sm) 2 O 3 nanoparticle layers that may be tilted relative to the film normal and REBCO orientation. Small shifts in the angular dependence of J c in low and intermediate applied magnetic fields can be associated with the tilted nanoparticle layers. Also present in these films were YCuO 2 nanoplates aligned with the YBCO matrix (short dimension perpendicular to the film normal), threading dislocations, and oriented composite defects (OCDs). The latter structures consist of single or multiple a-axis oriented grains coated on each side with insulating (Y,Sm) 2 O 3 or CuO. The OCDs formed a connected network of insulating phases by the end of the fourth pass. Subsequent attempts at adding additional layers did not increase I c . There is an inconsistency between the measured J c and the observed microstructural degradation that occurs with each additional layer, suggesting that previously deposited layers are improving with each repeated reactor pass. These dynamic changes suggest a role for post-processing to optimize superconducting properties of as-deposited films, addressing issues associated with reproducibility and manufacturing yield.

  6. Modifications in the chemical compounds and sensorial attributes of Engraulis anchoita fillet during marinating process

    Directory of Open Access Journals (Sweden)

    Maria Isabel Yeannes

    2008-12-01

    Full Text Available Marinated fish are fish products preserved by the combined action of salt and organic acids. The objective of this work was to analyze the variations in the chemical compounds of anchovy fillets that give them sensorial characteristics during the marinating process of Engraulis anchoita. The protein content decreased slightly and the TVB-N level decreased significantly in both the brining and marinating stages. In the marinating stage an increase in the total free aminoacids was observed. The NBV level in the brining and marinating solutions increased during these stages due to the solubilization of the non-protein nitrogenous compounds and the degradation of some protein compounds.The decrease of the contents of protein and TVB-N, and the increase of the acidity and the free aminoacids content during the marinating process give the marinated fillets the characteristic texture and aroma.Peixes marinados são produtos obtidos pela ação combinada de sal e ácidos orgânicos. O presente estudo teve como objetivo avaliar as alterações químicas e sensoriais em filés de anchoita (Engraulis anchoita durante o processo de marinado. O conteúdo de proteína apresentou decréscimo significativo durante a salga. O teor de Bases Voláteis Totais-N-BVT, apresentou uma diminuição considerável durante a salga e marinacão. Na fase de marinado, foi observado um aumento em aminoácidos livres totais. Foi constatada a presença de N-BVT na salmoura e na solução oriunda do processo de obtenção de marinado, devido à solubilização de nitrogênio não protéico, que podem ter sido acrescidos de alguns compostos de degradação protéica. A redução do conteúdo de proteína e N-BVT e o aumento de acidez e de aminoácidos livres gerados durante ou processo de elaboração do marinado fazem com que os filés marinados adquiram textura e aroma característicos.

  7. Combining color chart, colorimetric measurement and chemical compounds for postharvest quality of white wine grapes.

    Science.gov (United States)

    Sollazzo, Marco; Baccelloni, Simone; D'Onofrio, Claudio; Bellincontro, Andrea

    2018-01-03

    This paper provides data for the potential use of a color chart to establish the best quality of white wine grapes destined for postharvest processing. Grechetto, Vermentino and Muscat of Alexandria white wine grape varieties were tested by sampling berries at different dates during their quality attribute evolution. A color chart and reflectance spectrocolorimeter were used in combination with analyses of total carotenoids and chlorophylls in all three varieties and of volatile organic compounds (VOCs) in Grechetto alone. Total carotenoids decreased from 0.85 to 0.76 µg g -1 in Grechetto berries and from 0.70 to 0.46 µg g -1 in Vermentino berries while increased from 0.70 to 0.80 µg g -1 in Muscat berries during ripening. Total chlorophylls decreased in all varieties, and a strict correlation was found between hue angle (measured by color chart or spectrocolorimeter) and chlorophyll disappearance, with R 2 ranging from 0.81 to 0.95 depending on the variety. VOCs were only measured in Grechetto grapes, and a significant increase in glycosylation was found with ripening. The concentration of different classes of VOCs exhibited a clear decrease during ripening, except for terpenoids and esters which showed a peak at the beginning. The benzenoid class reached the highest concentration, which was almost 50% of the total. Cluster analysis using Ward's method enabled the best grape quality to be identified. This experimental work highlights that a color chart is cheap and easy to use to define the right quality stage for white wine grapes. The color chart enabled the enochemical features to be matched with the VOC results for the aromatic maturity of Grechetto. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  8. A detailed chemical kinetic model for pyrolysis of the lignin model compound chroman

    Directory of Open Access Journals (Sweden)

    James Bland

    2013-12-01

    Full Text Available The pyrolysis of woody biomass, including the lignin component, is emerging as a potential technology for the production of renewable fuels and commodity chemicals. Here we describe the construction and implementation of an elementary chemical kinetic model for pyrolysis of the lignin model compound chroman and its reaction intermediate ortho-quinone methide (o-QM. The model is developed using both experimental and theoretical data, and represents a hybrid approach to kinetic modeling that has the potential to provide molecular level insight into reaction pathways and intermediates while accurately describing reaction rates and product formation. The kinetic model developed here can replicate all known aspects of chroman pyrolysis, and provides new information on elementary reaction steps. Chroman pyrolysis is found to proceed via an initial retro-Diels–Alder reaction to form o-QM + ethene (C2H4, followed by dissociation of o-QM to the C6H6 isomers benzene and fulvene (+ CO. At temperatures of around 1000–1200 K and above fulvene rapidly isomerizes to benzene, where an activation energy of around 270 kJ mol-1 is required to reproduce experimental observations. A new G3SX level energy surface for the isomerization of fulvene to benzene supports this result. Our modeling also suggests that thermal decomposition of fulvene may be important at around 950 K and above. This study demonstrates that theoretical protocols can provide a significant contribution to the development of kinetic models for biomass pyrolysis by elucidating reaction mechanisms, intermediates, and products, and also by supplying realistic rate coefficients and thermochemical properties.

  9. Color superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Wilczek, F. [Institute for Advanced Study, Princeton, NJ (United States)

    1997-09-22

    The asymptotic freedom of QCD suggests that at high density - where one forms a Fermi surface at very high momenta - weak coupling methods apply. These methods suggest that chiral symmetry is restored and that an instability toward color triplet condensation (color superconductivity) sets in. Here I attempt, using variational methods, to estimate these effects more precisely. Highlights include demonstration of a negative pressure in the uniform density chiral broken phase for any non-zero condensation, which we take as evidence for the philosophy of the MIT bag model; and demonstration that the color gap is substantial - several tens of MeV - even at modest densities. Since the superconductivity is in a pseudoscalar channel, parity is spontaneously broken.

  10. Jabuticaba (Myrciaria cauliflora) Seeds: Chemical Characterization and Extraction of Antioxidant and Antimicrobial Compounds.

    Science.gov (United States)

    Hacke, Ana Carolina Mendes; Granato, Daniel; Maciel, Laércio Galvão; Weinert, Patrícia Los; Prado-Silva, Leonardo do; Alvarenga, Verônica Ortiz; de Souza Sant'Ana, Anderson; Bataglion, Giovana Anceski; Eberlin, Marcos Nogueira; Rosso, Neiva Deliberali

    2016-09-01

    This study was aimed to assess the effect of time and temperature on the extraction of antioxidant compounds from jabuticaba seeds (Myrciaria cauliflora cv. Sabará), to optimize the solvent proportion (water, ethyl alcohol, and propanone), and to characterize the extract according to the chemical composition, antioxidant, and antimicrobial properties. Proximal composition, total phenolic content (TPC), antioxidant, and antimicrobial activities were analyzed. The optimized solvent ratio of 60% water and 40% propanone provided a mean TPC of 8.65 g GAE/100 g seeds and the antioxidant activity toward 2,2-diphenyl-1-picrylhydrazyl (DPPH) was 82.79% ± 0.50%. Time and temperature parameters did not influence the yield of TPC. The gross seed extract was partially purified and both exhibited a high antioxidant activity and antimicrobial potential toward Gram-positive and Gram-negative bacteria. The purified jabuticaba seed lyophilized extract contained a higher (P < 0.05) TPC, o-diphenols, flavonols, and antioxidant activity measured by the DPPH assay and total reducing capacity as compared to the gross lyophilized extract. Electrospray ionization coupled with tandem mass spectrometry (ESI-MS/MS) data showed the presence of ellagitannins and ellagic acid in the extracts, which are probably the responsible for the antimicrobial and antioxidant activities. © 2016 Institute of Food Technologists®

  11. Prodrugs: a chemical method for targeting pharmacologically active compounds to the brain

    Energy Technology Data Exchange (ETDEWEB)

    Donati, D.; De Magistris, E.; Messeri, T. [Glaxo Wellcome Medicines Research Centre, Verona (Italy)

    1999-11-01

    The diffusion of compounds from the blood into the brain is complicated by the presence of the Blood Brain Barrier, that is a membrane that segregates the brain interstitial fluid from the circulating blood. In designing drugs active in the central nervous system and able to cross the BBB, one can exploit endogenous active mechanisms, utilise proper delivery techniques or modify a chemical structure through the synthesis of proper prodrug derivatives. The application of the prodrug technology is discussed in detail in the present paper, with examples illustrating such an approach to a number of therapeutic areas. [Italiano] La diffusione di sostanze dal sangue all`interno del cervello puo` avvenire sia attraverso meccanismi attivi che passivi; la presenza della barriera ematoencefalica (BBB), che rende i vasi cerebrali meno permeabili ai diversi soluti, complica notevolmente tali processi di diffusione. Nella progettazione di nuovi farmaci attivi sul sistema nervoso centrale e capaci di attraversare la BBB, si puo` cercare di sfruttare i meccanismi di trasporto, sia attivi che passivi, utilizzare opportuni sistemi di rilascio, o, infine, modificare la struttura del principio attivo attraverso la sintesii di opportuni prodrug. Proprio quest`ultima tecnologia e` oggetto di discussione nel presente articolo, dove vengono presentati esempi di applicazione nell`ambito di diverse aree terapeutiche.

  12. Chemical genetics reveals an RGS/G-protein role in the action of a compound.

    Directory of Open Access Journals (Sweden)

    Kevin Fitzgerald

    2006-04-01

    Full Text Available We report here on a chemical genetic screen designed to address the mechanism of action of a small molecule. Small molecules that were active in models of urinary incontinence were tested on the nematode Caenorhabditis elegans, and the resulting phenotypes were used as readouts in a genetic screen to identify possible molecular targets. The mutations giving resistance to compound were found to affect members of the RGS protein/G-protein complex. Studies in mammalian systems confirmed that the small molecules inhibit muscarinic G-protein coupled receptor (GPCR signaling involving G-alphaq (G-protein alpha subunit. Our studies suggest that the small molecules act at the level of the RGS/G-alphaq signaling complex, and define new mutations in both RGS and G-alphaq, including a unique hypo-adapation allele of G-alphaq. These findings suggest that therapeutics targeted to downstream components of GPCR signaling may be effective for treatment of diseases involving inappropriate receptor activation.

  13. Bioactive chemical compounds in Eremurus persicus (Joub. & Spach) Boiss. essential oil and their health implications.

    Science.gov (United States)

    Salehi, B; Ayatollahi, S A; Segura-Carretero, A; Kobarfard, F; Contreras, M D M; Faizi, M; Sharifi-Rad, M; Tabatabai, S A; Sharifi-Rad, J

    2017-09-30

    The genus Eremurus is native to Eastern Europe and temperate Asia. Particularly, Eremurus persicus (Joub. & Spach) Boiss. is highly valued in traditional foods and medicine. Scientific knowledge about E. persicus chemical composition and bioactivity is required. Therefore, the present study is aimed to determine the volatile composition of E. persicus essential oil (EO) by means of gas chromatography coupled to flame ionization/mass spectrometry detection. Moreover, the antioxidant, antimicrobial, anticancer, and acetylcholinesterase inhibitory activities of the EO were tested. Interestingly, the anti-dermatophyte potency was close to that of the drug griseofulvin, with minimum fungicidal concentration ranging between 0.7 and 4.5% depending on the fungi strain. The EO was also effective against hepatocellular carcinoma (Hep-G2) and breast adenocarcinoma (MCF-7) human cancer cell lines in a concentration (200-1500 ng/mL)-dependent manner, with a decrease of the cell viability up to 65% and 52%, respectively. The E. persicus EO was rich in terpenes and oxygenated terpene derivatives. Individually, limonene (16.25%), geranylgeraniol (15.23%), n-nonanal (9.48%), geranyl acetone (9.12%), benzene acetaldehyde (8.51%), linalool (7.93%), α-pinene (6.89%), and 1,8-cineol (5.22%) were the most abundant volatile compounds and could be chosen as analytical markers of this essential oil. In conclusion, our results suggested that this EO possesses a wide range of bioactive properties that could be useful in nutraceutical, functional foods and cosmeceutical formulations.

  14. Antidiabetic Activities and Identification of Chemical Compound from Samama (Anthocephalus macrophyllus (Roxb Havil

    Directory of Open Access Journals (Sweden)

    Laela Nur Anisah

    2018-02-01

    Full Text Available Samama (Anthocephalus macrophyllus is one of a pioneer indigenous fast growing species in Indonesia which have been used as traditional medicine for various diseases. The objectives were to determine the yield extract, to analyze their antidiabetic activity by inhibition assay for α-glucosidase enzyme activity and chemical analysis with GCMS. Extraction of leaves, bark and wood samples were done by using ethanol 95%. Fractionation the most active  ethanol extract was conducted by using n-hexane and ethyl acetate. The yield of ethanol extracts in leaves, bark and wood were 13.90%, 12.87%, and 2.18% respectively. Based on antidiabetic activity assay, the bark ethanol extract was the most active extract by the IC50 value of 5.86 μg mL-1. Phytochemical analysis on bark ethanol extracts showed that they contained flavonoid, quinon, triterpenoid, saponin and tannin which were assumed have high contribution in antidiabetic activities. The result of fractionation ethanol extract bark showed that the ethyl acetate fraction was the most active fraction (IC50 6.82 μg mL-1. GCMS analysis indicated the presence of dominant phenolic compounds such as pyrocatechol, antiarol, isopropyl myristate and phenol in which were suspected have antidiabetic activity. These results strongly suggested that ethyl acetate fraction of Samama bark was a potential natural source for antidiabetic agents.

  15. Nature of the chemical bond and prediction of radiation tolerance in pyrochlore and defect fluorite compounds

    International Nuclear Information System (INIS)

    Lumpkin, Gregory R.; Pruneda, Miguel; Rios, Susana; Smith, Katherine L.; Trachenko, Kostya; Whittle, Karl R.; Zaluzec, Nestor J.

    2007-01-01

    The radiation tolerance of synthetic pyrochlore and defect fluorite compounds has been studied using ion irradiation. We show that the results can be quantified in terms of the critical temperature for amorphization, structural parameters, classical Pauling electronegativity difference, and disorder energies. Our results demonstrate that radiation tolerance is correlated with a change in the structure from pyrochlore to defect fluorite, a smaller unit cell dimension, and lower cation-anion disorder energy. Radiation tolerance is promoted by an increase in the Pauling cation-anion electronegativity difference or, in other words, an increase in the ionicity of the chemical bonds. A further analysis of the data indicates that, of the two possible cation sites in ideal pyrochlore, the smaller B-site cation appears to play the major role in bonding. This result is supported by ab initio calculations of the structure and bonding, showing a correlation between the Mulliken overlap populations of the B-site cation and the critical temperature. - Graphical abstract: Three-dimensional representation of the predicted critical amorphization temperature in pyrochlores

  16. Side by Side Comparison of Chemical Compounds Generated by Aqueous Pretreatments of Maize Stover, Miscanthus and Sugarcane Bagasse

    NARCIS (Netherlands)

    Gomez, L.D.; Vanholme, R.; Bird, S.; Goeminne, G.; Trindade, L.M.; Polikarpov, I.; Simister, R.; Morreel, K.; Boerjan, W.; McQueen-Mason, S.J.

    2014-01-01

    In order to examine the potential for coproduct generation, we have characterised chemical compounds released by a range of alkaline and acidic aqueous pretreatments as well as the effect of these pretreatments on the saccharification ability of the lignocellulosic material. Comparative experiments

  17. Structure-metabolism relationships inhuman-AOX: Chemical insights from a large database of aza-aromatic and amide compounds.

    Science.gov (United States)

    Lepri, Susan; Ceccarelli, Martina; Milani, Nicolò; Tortorella, Sara; Cucco, Andrea; Valeri, Aurora; Goracci, Laura; Brink, Andreas; Cruciani, Gabriele

    2017-04-18

    Aldehyde oxidase (AOX) is a metabolic enzyme catalyzing the oxidation of aldehyde and aza-aromatic compounds and the hydrolysis of amides, moieties frequently shared by the majority of drugs. Despite its key role in human metabolism, to date only fragmentary information about the chemical features responsible for AOX susceptibility are reported and only "very local" structure-metabolism relationships based on a small number of similar compounds have been developed. This study reports a more comprehensive coverage of the chemical space of structures with a high risk of AOX phase I metabolism in humans. More than 270 compounds were studied to identify the site of metabolism and the metabolite(s). Both electronic [supported by density functional theory (DFT) calculations] and exposure effects were considered when rationalizing the structure-metabolism relationship.

  18. A quantum chemical based toxicity study of estimated reduction potential and hydrophobicity in series of nitroaromatic compounds.

    Science.gov (United States)

    Gooch, A; Sizochenko, N; Sviatenko, L; Gorb, L; Leszczynski, J

    2017-02-01

    Nitroaromatic compounds and the products of their degradation are toxic to bacteria, cells and animals. Various studies have been carried out to better understand the mechanism of toxicity of aromatic nitrocompounds and their relationship to humans and the environment. Recent data relate cytotoxicity of nitroaromatic compounds to their single- or two-electron enzymatic reduction. However, mechanisms of animal toxicity could be more complex. This work investigates the estimated reduction and oxidation potentials of 34 nitroaromatic compounds using quantum chemical approaches. All geometries were optimized with density functional theory (DFT) using the solvation model based on density (SMD) and polarizable continuum model (PCM) solvent model protocols. Quantitative structure-activity/property (QSAR/QSPR) models were developed using descriptors obtained from quantum chemical optimizations as well as the DRAGON software program. The QSAR/QSPR equations developed consist of two to four descriptors. Correlations have been identified between electron affinity (E LUMO ) and hydrophobicity (log P).

  19. CFam: a chemical families database based on iterative selection of functional seeds and seed-directed compound clustering.

    Science.gov (United States)

    Zhang, Cheng; Tao, Lin; Qin, Chu; Zhang, Peng; Chen, Shangying; Zeng, Xian; Xu, Feng; Chen, Zhe; Yang, Sheng Yong; Chen, Yu Zong

    2015-01-01

    Similarity-based clustering and classification of compounds enable the search of drug leads and the structural and chemogenomic studies for facilitating chemical, biomedical, agricultural, material and other industrial applications. A database that organizes compounds into similarity-based as well as scaffold-based and property-based families is useful for facilitating these tasks. CFam Chemical Family database http://bidd2.cse.nus.edu.sg/cfam was developed to hierarchically cluster drugs, bioactive molecules, human metabolites, natural products, patented agents and other molecules into functional families, superfamilies and classes of structurally similar compounds based on the literature-reported high, intermediate and remote similarity measures. The compounds were represented by molecular fingerprint and molecular similarity was measured by Tanimoto coefficient. The functional seeds of CFam families were from hierarchically clustered drugs, bioactive molecules, human metabolites, natural products, patented agents, respectively, which were used to characterize families and cluster compounds into families, superfamilies and classes. CFam currently contains 11,643 classes, 34,880 superfamilies and 87,136 families of 490,279 compounds (1691 approved drugs, 1228 clinical trial drugs, 12,386 investigative drugs, 262,881 highly active molecules, 15,055 human metabolites, 80,255 ZINC-processed natural products and 116,783 patented agents). Efforts will be made to further expand CFam database and add more functional categories and families based on other types of molecular representations. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  20. Formation of chemical compounds from irradiated mixtures of aromatic hydrocarbons and nitrogen oxides

    NARCIS (Netherlands)

    Besemer, A.C.

    1982-01-01

    The paper describes the analysis of products of the photochemical degradation of toluene and toluene-14C in smog chamber experiments. Compounds identified included methylglyoxal, possibly the recently postulated butenedial and other carbonyl compounds. The main product of photochemical degradation

  1. Comparison of the Chemical Composition of “Cystoseira sedoides (Desfontaines C. Agardh” Volatile Compounds Obtained by Different Extraction Techniques

    Directory of Open Access Journals (Sweden)

    Naima Bouzidi

    2016-01-01

    Full Text Available The volatile fraction of the brown alga Cystoseira sedoides (Desfontaines C.Agardh is prepared from the crude extract through the following three extraction methods: Hydrodistillation (HD, focused microwave assisted hydrodistillation (FMAHD and supercritical fluid extraction (SFE. The volatile fractions are analyzed by gas chromatography-flame ionization detector-mass spectrometry (GC-FID-MS, the chemical components are identified on the basis of the comparison of their retention indices with literature and their mass spectra with those reported in commercial databases. The chemical composition of the volatile fractions obtained by different extraction techniques fall into three major chemical classes: fatty acids and derivatives, sesquiterpenes, and hydrocarbons and derivatives. Others Compounds belonging to different chemical classes are found in that chemical composition.

  2. Sexual Differences in Chemical Composition and Aroma-active Compounds of Essential Oil from Flower Buds of Eurya japonica.

    Science.gov (United States)

    Miyazawa, Mitsuo; Usami, Atsushi; Tanaka, Takio; Tsuji, Kaoru; Takehara, Manami; Hori, Yuki

    2016-01-01

    This study was conducted to determine the composition of essential oil from buds of male and female Eurya japonica flowers and to determine the aroma-active compounds of this plant by gas chromatography-mass spectrometry (GC-MS), sensory evaluation, and odor activity values (OAV). The oils contained eighty-five compounds. We identified for the first time forty-four compounds in E. japonica. Through sensory evaluation, nineteen aroma-active compounds were identified by gas chromatography-olfactometry (GC-O). Because the chemical composition can affect the interaction between plants and herbivorous insects, our results suggest that essential oils from male and female flower buds of E. japonica differently affect herbivores. Sexual differences in essential oils deserve further investigations in this plant-insect system.

  3. Monolayer Superconductivity in WS2

    NARCIS (Netherlands)

    Zheliuk, Oleksandr; Lu, Jianming; Yang, Jie; Ye, Jianting

    Superconductivity in monolayer tungsten disulfide (2H-WS2) is achieved by strong electrostatic electron doping of an electric double-layer transistor (EDLT). Single crystals of WS2 are grown by a scalable method - chemical vapor deposition (CVD) on standard Si/SiO2 substrate. The monolayers are

  4. Identification of IAA transport inhibitors including compounds affecting cellular PIN trafficking by two chemical screening approaches using maize coleoptile systems.

    Science.gov (United States)

    Nishimura, Takeshi; Matano, Naoyuki; Morishima, Taichi; Kakinuma, Chieko; Hayashi, Ken-Ichiro; Komano, Teruya; Kubo, Minoru; Hasebe, Mitsuyasu; Kasahara, Hiroyuki; Kamiya, Yuji; Koshiba, Tomokazu

    2012-10-01

    The monocot coleoptile tip region has been generally supposed to be the source of IAA to supply IAA to basal parts by the polar IAA transport system, which results in gravi- and phototropic curvature of coleoptiles. Based on this IAA transport system and gravitropism of maize coleoptiles, we have developed two screening methods to identify small molecules from a large chemical library that inhibit IAA transport. The methods detect molecules that affect (i) gravitropic curvature of coleoptiles; and (ii) the amount of IAA transported from the tip. From 10,000 chemicals, eight compounds were identified and categorized into two groups. Four chemicals in group A decreased IAA transport from the tip, and increased endogenous IAA levels in the tip. The structures of two compounds resembled that of 1-N-naphthylphthalamic acid (NPA), but those of the other two differed from structures of known IAA transport inhibitors. Four chemicals in group B strongly inhibited IAA transport from the tip, but IAA levels at the tip were only slightly affected. At higher concentrations, group B compounds inhibited germination of Arabidopsis, similarly to brefeldin A (BFA). Analysis of the cellular distribution of PIN2-green fluorescent protein (GFP) and PIN1-GFP in Arabidopsis revealed that one of the four chemicals in group B induced internalization of PIN1 and PIN2 proteins into vesicles smaller than BFA bodies, suggesting that this compound affects cellular vesicle trafficking systems related to PIN trafficking. The eight chemicals identified here will be a useful tool for understanding the mechanisms of IAA transport in plants.

  5. Effects of composition on microstructure and superconducting properties of YBa 2Cu 3O 7- x thin films prepared by plasma enhanced metalorganic chemical vapor deposition

    Science.gov (United States)

    Li, Y. Q.; Zhao, J.; Chern, C. S.; Lu, P.; Gallois, B.; Norris, P.; Kear, B.; Cosandey, F.

    1992-05-01

    The microstructure and the superconducting properties of YBa 2Cu 3O 7- x thin films prepared by plasma-enhanced metalorganic chemical vapor deposition have been investigated systematically as a function of metal composition. Yttria precipitates are not apparent on the surface of yttrium-rich films. They are densely distributed within the films, their average size is of the order of 5-10 nm and their density can be as high as 10 24/m 3. Excess copper leads to the precipitation of copper oxide (CuO) particles on the surface of the films, but they are not found in the bulk. High transition temperatures and high critical current densities have been obtained over a wide range of compositions. Transition temperatures higher than 86 K are always obtained when the Cu/Ba ratio is larger than the stoichiometric ratio of 1.5. Films with Cu/Ba ratio larger than 1.5 and a Ba/Y ratio less than 1.7 usually have a critical current density larger than 10 6 A/cm 2 at 77 K and 0 T. The dependence of the critical current density on temperature follows a power law, Jc A(1- T/ Tc) n. The value of n is 2 for stoichiometric and barium-rich films and 1 for yttrium-rich films. The best films with transition temperatures of 90K, critical current densities in excess of 10 6 A/cm 2 at 77.5 K, and smooth surfaces are observed when the Ba/Y ration is around 1.6 and the Cu/Ba ratio is around 1.8.

  6. Chemical reactivities of the superconducting oxides, YBa2Cu3Oy and BiSrCaCu2Oy

    International Nuclear Information System (INIS)

    Toyama, Hisashi; Mizuno, Noritaka; Misono, Makoto

    1989-01-01

    The chemical reactivities of YBa 2 Cu 3 O y and BiSrCaCu 2 O y with various gases have been studied. It was found that large quantities of NO, CO, and NO 2 were rapidly absorbed (or intercalated) in the bulk of YBa 2 Cu 3 O y (T c : 90 K) at 573 K. The amount absorbed was in the order NO ∼ CO ∼ NO 2 > O 2 ∼ CO 2 > N 2 O ∼ 0. The amount for NO was more than two times the amount of YBa 2 Cu 3 O y in molar ratio and elongation by about 0.2 angstrom along c-axis was observed. NO absorbed was almost completely recovered as NO by the evacuation at 773 K. This absorption-desorption cycle proceeded reversively. The electronic resistivity at 573 K of YBa 2 Cu 3 O y increased upon the NO absorption and was restored by the evacuation at 773 K. CO was also absorbed rapidly accompanied by evolution of CO 2 . BiSrCaCu 2 O y did not absorb either NO or CO

  7. Magnetic imaging of antiferromagnetic and superconducting phases in R bxF e2 -yS e2 crystals

    Science.gov (United States)

    Hazi, J.; Mousavi, T.; Dudin, P.; van der Laan, G.; Maccherozzi, F.; Krzton-Maziopa, A.; Pomjakushina, E.; Conder, K.; Speller, S. C.

    2018-02-01

    High-temperature superconducting (HTS) cuprate materials, with the ability to carry large electrical currents with no resistance at easily reachable temperatures, have stimulated enormous scientific and industrial interest since their discovery in the 1980's. However, technological applications of these promising compounds have been limited by their chemical and microstructural complexity and the challenging processing strategies required for the exploitation of their extraordinary properties. The lack of theoretical understanding of the mechanism for superconductivity in these HTS materials has also hindered the search for new superconducting systems with enhanced performance. The unexpected discovery in 2008 of HTS iron-based compounds has provided an entirely new family of materials for studying the crucial interplay between superconductivity and magnetism in unconventional superconductors. Alkali-metal-doped iron selenide (AxF e2 -yS e2 , A =alkali metal ) compounds are of particular interest owing to the coexistence of superconductivity at relatively high temperatures with antiferromagnetism. Intrinsic phase separation on the mesoscopic scale is also known to occur in what were intended to be single crystals of these compounds, making it difficult to interpret bulk property measurements. Here, we use a combination of two advanced microscopy techniques to provide direct evidence of the magnetic properties of the individual phases. First, x-ray linear dichroism studies in a photoelectron emission microscope, and supporting multiplet calculations, indicate that the matrix (majority) phase is antiferromagnetic whereas the minority phase is nonmagnetic at room temperature. Second, cryogenic magnetic force microscopy demonstrates unambiguously that superconductivity occurs only in the minority phase. The correlation of these findings with previous microstructural studies and bulk measurements paves the way for understanding the intriguing electronic and magnetic

  8. Modern aspects of superconductivity theory of superconductivity

    CERN Document Server

    Kruchinin, Sergei; Aono, Shigeyuki

    2011-01-01

    Superconductivity remains one of the most interesting research areas in physics and stood as a major scientific mystery for a large part of this century. This book, written for graduate students and researchers in the field of superconductivity, discusses important aspects of the experiment and theory surrounding superconductivity. New experimental investigations of magnetic and thermodynamic superconducting properties of mesoscopic samples are explored with the help of recent developments in nanotechnologies and measurement techniques, and the results are predicted based upon theoretical mode

  9. Chemical Diversity and Antimicrobial Activity of Volatile Compounds from Zanthoxylum zanthoxyloides Lam. according to Compound Classes, Plant Organs and Senegalese Sample Locations.

    Science.gov (United States)

    Tine, Yoro; Diop, Abdoulaye; Diatta, William; Desjobert, Jean-Marie; Boye, Cheikh Saad Bouh; Costa, Jean; Wélé, Alassane; Paolini, Julien

    2017-01-01

    The chemical diversity of Zanthoxylum zanthoxyloides growing wild in Senegal was studied according to volatile compound classes, plant organs and sample locations. The composition of fruit essential oil was investigated using an original targeted approach based on the combination of gas chromatography (GC) and liquid chromatography (LC) both coupled with mass spectrometry (MS). The volatile composition of Z. zanthoxyloides fruits exhibited relative high amounts of hydrocarbon monoterpenes (24.3 - 55.8%) and non-terpenic oxygenated compounds (34.5 - 63.1%). The main components were (E)-β-ocimene (12.1 - 39%), octyl acetate (11.6 - 21.8%) and decanol (9.7 - 15.4%). The GC and GC/MS profiling of fruit essential oils showed a chemical variability according to geographical locations of plant material. The LC/MS/MS analysis of fruit oils allowed the detection of seven coumarins in trace content. The chemical composition of fruit essential oils was compared with volatile fractions of leaves and barks (root and trunk) from the same plant station. Hexadecanoic acid, germacrene D and decanal were identified as the major constituents of leaves whereas the barks (root and trunk) were dominated by pellitorine (85.8% and 57%, respectively), an atypic linear compound with amide group. The fruit essential oil exhibited interesting antimicrobial activities against Staphylococcus aureus and Candida albicans, particularly the alcohol fraction of the oil. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

  10. Superconducting plasmas

    International Nuclear Information System (INIS)

    Ohnuma, Toshiro; Ohno, J.

    1994-01-01

    Superconducting (SC) plasmas are proposed and investigated. The SC plasmas are not yet familiar and have not yet been studied. However, the existence and the importance of SC plasmas are stressed in this report. The existence of SC plasmas are found as follows. There is a fundamental property of Meissner effect in superconductors, which shows a repulsive effect of magnetic fields. Even in that case, in a microscopic view, there is a region of magnetic penetration. The penetration length λ is well-known as London's penetration depth, which is expressed as δ = (m s /μ 0 n s q s 2 ) 1/2 where m s , n s , q s and μ o show the mass, the density, the charge of SC electron and the permeability in free space, respectively. Because this expression is very simple, no one had tried it into more simple and meaningful form. Recently, one of the authors (T.O.) has found that the length can be expressed into more simple and understandable fundamental form as λ = c/ω ps where c = (ε 0 μ 0 ) -1/2 and ω ps = (n s q s 2 /m s ε 0 ) 1/2 are the light velocity and the superconducting plasma frequency. From this simple expression, the penetration depth of the magnetic field to SC is found as a SC plasma skin depth, that is, the fundamental property of SC can be expressed by the SC plasmas. This discovery indicates an importance of the studies of superconducting plasmas. From these points, several properties (propagating modes et al) of SC plasmas, which consist of SC electrons, normal electrons and lattice ions, are investigated in this report. Observations of SC plasma frequency is also reported with a use of Terahertz electromagnet-optical waves

  11. Predicting Heats of Explosion of Nitroaromatic Compounds through NBO Charges and 15N NMR Chemical Shifts of Nitro Groups

    Directory of Open Access Journals (Sweden)

    Ricardo Infante-Castillo

    2012-01-01

    Full Text Available This work presents a new quantitative model to predict the heat of explosion of nitroaromatic compounds using the natural bond orbital (NBO charge and 15N NMR chemical shifts of the nitro groups (15NNitro as structural parameters. The values of the heat of explosion predicted for 21 nitroaromatic compounds using the model described here were compared with experimental data. The prediction ability of the model was assessed by the leave-one-out cross-validation method. The cross-validation results show that the model is significant and stable and that the predicted accuracy is within 0.146 MJ kg−1, with an overall root mean squared error of prediction (RMSEP below 0.183 MJ kg−1. Strong correlations were observed between the heat of explosion and the charges (R2 = 0.9533 and 15N NMR chemical shifts (R2 = 0.9531 of the studied compounds. In addition, the dependence of the heat of explosion on the presence of activating or deactivating groups of nitroaromatic explosives was analyzed. All calculations, including optimizations, NBO charges, and 15NNitro NMR chemical shifts analyses, were performed using density functional theory (DFT and a 6-311+G(2d,p basis set. Based on these results, this practical quantitative model can be used as a tool in the design and development of highly energetic materials (HEM based on nitroaromatic compounds.

  12. Sulfonamides identified as plant immune-priming compounds in high-throughput chemical screening increase disease resistance in Arabidopsis thaliana.

    Science.gov (United States)

    Noutoshi, Yoshiteru; Ikeda, Mika; Saito, Tamio; Osada, Hiroyuki; Shirasu, Ken

    2012-01-01

    Plant activators are agrochemicals that protect crops from diseases by activating the plant immune system. To isolate lead compounds for use as practical plant activators, we screened two different chemical libraries composed of various bioactive substances by using an established screening procedure that can selectively identify immune-priming compounds. We identified and characterized a group of sulfonamide compounds - sulfameter, sulfamethoxypyridazine, sulfabenzamide, and sulfachloropyridazine - among the various isolated candidate molecules. These sulfonamide compounds enhanced the avirulent Pseudomonas-induced cell death of Arabidopsis suspension cell cultures and increased disease resistance in Arabidopsis plants against both avirulent and virulent strains of the bacterium. These compounds did not prevent the growth of pathogenic bacteria in minimal liquid media at 200 μM. They also did not induce the expression of defense-related genes in Arabidopsis seedlings, at least not at 24 and 48 h after treatment, suggesting that they do not act as salicylic acid analogs. In addition, although sulfonamides are known to be folate biosynthesis inhibitors, the application of folate did not restore the potentiation effects of the sulfonamides on pathogen-induced cell death. Our data suggest that sulfonamides potentiate Arabidopsis disease resistance by their novel chemical properties.

  13. A Comparative Study of Two Quantum Chemical Descriptors in Predicting Toxicity of Aliphatic Compounds towards Tetrahymena pyriformis

    Directory of Open Access Journals (Sweden)

    Altaf Hussain Pandith

    2010-01-01

    Full Text Available Quantum chemical parameters such as LUMO energy, HOMO energy, ionization energy (I, electron affinity (A, chemical potential (μ, hardness (η electronegativity (χ, philicity (ωα, and electrophilicity (ω of a series of aliphatic compounds are calculated at the B3LYP/6-31G(d level of theory. Quantitative structure-activity relationship (QSAR models are developed for predicting the toxicity (pIGC50 of 13 classes of aliphatic compounds, including 171 electron acceptors and 81 electron donors, towards Tetrahymena pyriformis. The multiple linear regression modeling of toxicity of these compounds is performed by using the molecular descriptor log P (1-octanol/water partition coefficient in conjunction with two other quantum chemical descriptors, electrophilicity (ω and energy of the lowest unoccupied molecular orbital (ELUMO. A comparison is made towards the toxicity predicting the ability of electrophilicity (ω versus ELUMO as a global chemical reactivity descriptor in addition to log P. The former works marginally better in most cases. There is a slight improvement in the quality of regression by changing the unit of IGC50 from mg/L to molarity and by removing the racemates and the diastereoisomers from the data set.

  14. In silico approaches and chemical space of anti-P-type ATPase compounds for discovering new antituberculous drugs.

    Science.gov (United States)

    Santos, Paola; López-Vallejo, Fabian; Soto, Carlos-Y

    2017-08-01

    Tuberculosis (TB) is one of the most important public health problems around the world. The emergence of multi-drug-resistant (MDR) and extensively drug-resistant (XDR) Mycobacterium tuberculosis strains has driven the finding of alternative anti-TB targets. In this context, P-type ATPases are interesting therapeutic targets due to their key role in ion homeostasis across the plasma membrane and the mycobacterial survival inside macrophages. In this review, in silico and experimental strategies used for the rational design of new anti-TB drugs are presented; in addition, the chemical space distribution based on the structure and molecular properties of compounds with anti-TB and anti-P-type ATPase activity is discussed. The chemical space distribution compared to public compound libraries demonstrates that natural product libraries are a source of novel chemical scaffolds with potential anti-P-type ATPase activity. Furthermore, compounds that experimentally display anti-P-type ATPase activity belong to a chemical space of molecular properties comparable to that occupied by those approved for oral use, suggesting that these kinds of molecules have a good pharmacokinetic profile (drug-like) for evaluation as potential anti-TB drugs. © 2017 John Wiley & Sons A/S.

  15. Currently Commercially Available Chemical Sensors Employed for Detection of Volatile Organic Compounds in Outdoor and Indoor Air

    Directory of Open Access Journals (Sweden)

    Bartosz Szulczyński

    2017-03-01

    Full Text Available The paper presents principle of operation and design of the most popular chemical sensors for measurement of volatile organic compounds (VOCs in outdoor and indoor air. It describes the sensors for evaluation of explosion risk including pellistors and IR-absorption sensors as well as the sensors for detection of toxic compounds such as electrochemical (amperometric, photoionization and semiconductor with solid electrolyte ones. Commercially available sensors for detection of VOCs and their metrological parameters—measurement range, limit of detection, measurement resolution, sensitivity and response time—were presented. Moreover, development trends and prospects of improvement of the metrological parameters of these sensors were highlighted.

  16. Towards inducing superconductivity into graphene

    Science.gov (United States)

    Efetov, Dmitri K.

    Graphenes transport properties have been extensively studied in the 10 years since its discovery in 2004, with ground-breaking experimental observations such as Klein tunneling, fractional quantum Hall effect and Hofstadters butterfly. Though, so far, it turned out to be rather poor on complex correlated electronic ground states and phase transitions, despite various theoretical predictions. The purpose of this thesis is to help understanding the underlying theoretical and experimental reasons for the lack of strong electronic interactions in graphene, and, employing graphenes high tunability and versatility, to identify and alter experimental parameters that could help to induce stronger correlations. In particular graphene holds one last, not yet experimentally discovered prediction, namely exhibiting intrinsic superconductivity. With its vanishingly small Fermi surface at the Dirac point, graphene is a semi-metal with very weak electronic interactions. Though, if it is doped into the metallic regime, where the size of the Fermi surface becomes comparable to the size of the Brillouin zone, the density of states becomes sizeable and electronic interactions are predicted to be dramatically enhanced, resulting in competing correlated ground states such as superconductivity, magnetism and charge density wave formation. Following these predictions, this thesis first describes the creation of metallic graphene at high carrier doping via electrostatic doping techniques based on electrolytic gates. Due to graphenes surface only properties, we are able to induce carrier densities above n>1014 cm-2 (epsilonF>1eV) into the chemically inert graphene. While at these record high carrier densities we yet do not observe superconductivity, we do observe fundamentally altered transport properties as compared to semi-metallic graphene. Here, detailed measurements of the low temperature resistivity reveal that the electron-phonon interactions are governed by a reduced, density

  17. Enhancement of the superconducting transition temperature of FeSe by intercalation of a molecular spacer layer.

    Science.gov (United States)

    Burrard-Lucas, Matthew; Free, David G; Sedlmaier, Stefan J; Wright, Jack D; Cassidy, Simon J; Hara, Yoshiaki; Corkett, Alex J; Lancaster, Tom; Baker, Peter J; Blundell, Stephen J; Clarke, Simon J

    2013-01-01

    The discovery of high-temperature superconductivity in a layered iron arsenide has led to an intensive search to optimize the superconducting properties of iron-based superconductors by changing the chemical composition of the spacer layer between adjacent anionic iron arsenide layers. Superconductivity has been found in iron arsenides with cationic spacer layers consisting of metal ions (for example, Li(+), Na(+), K(+), Ba(2+)) or PbO- or perovskite-type oxide layers, and also in Fe(1.01)Se (ref. 8) with neutral layers similar in structure to those found in the iron arsenides and no spacer layer. Here we demonstrate the synthesis of Li(x)(NH(2))(y)(NH(3))(1-y)Fe(2)Se(2) (x~0.6; y~0.2), with lithium ions, lithium amide and ammonia acting as the spacer layer between FeSe layers, which exhibits superconductivity at 43(1) K, higher than in any FeSe-derived compound reported so far. We have determined the crystal structure using neutron powder diffraction and used magnetometry and muon-spin rotation data to determine the superconducting properties. This new synthetic route opens up the possibility of further exploitation of related molecular intercalations in this and other systems to greatly optimize the superconducting properties in this family.

  18. Photocatalytic and chemical oxidation of organic compounds in supercritical carbon dioxide. 1998 annual progress report

    International Nuclear Information System (INIS)

    Blake, D.M.

    1998-01-01

    'This report summarizes the results of work done during the first 1.3 years of a three year project. During the first nine months effort focussed on the design, construction and testing of a closed recirculating system that can be used to study photochemistry in supercritical carbon dioxide at pressures up to 5,000 psi and temperatures up to about 50 C. This was followed by a period of work in which the photocatalytic oxidation of benzene and acetone in supercritical, liquid, and gaseous carbon dioxide containing dissolved oxygen was demonstrated. The photocatalyst was titanium dioxide supported on glass spheres. This was the first time it was possible to observe photocatalytic oxidation in a supercritical fluid and to compare reaction in the three fluid phases of a solvent. This also demonstrated that it is possible to purify supercritical and liquid carbon dioxide using photochemical oxidation with no chemical additions other than oxygen. The oxidation of benzene produced no intermediates detectable using on line spectroscopic analysis or by gas chromatographic analysis of samples taken from the flow system. The catalyst surface did darken as the reaction proceeded indicating that oxidation products were accumulating on the surface. This is analogous to the behavior of aromatic compounds in air phase photocatalytic oxidation. The reaction of acetone under similar conditions resulted in the formation of low levels of by-products. Two were identified as products of the reaction of acetone with itself (4-methyl-3-penten-2-one and 4-hydroxy-4-methyl-2-pentanone) using gas chromatography with a mass spectrometer detector. Two other by-products also appear to be from the self-reaction of acetone. By-products of this type had not been observed in prior studies of the gas-phase photocatalytic oxidation of acetone. The by-products that have been observed can also be oxidized under the treatment conditions. The above results establish that photocatalytic oxidation of

  19. Extraction, chemical characterization and biological activity determination of broccoli health promoting compounds.

    Science.gov (United States)

    Ares, Ana M; Nozal, María J; Bernal, José

    2013-10-25

    Broccoli (Brassica oleracea L. var. Italica) contains substantial amount of health-promoting compounds such as vitamins, glucosinolates, phenolic compounds, and dietary essential minerals; thus, it benefits health beyond providing just basic nutrition, and consumption of broccoli has been increasing over the years. This review gives an overview on the extraction and separation techniques, as well as the biological activity of some of the above mentioned compounds which have been published in the period January 2008 to January 2013. The work has been distributed according to the different families of health promoting compounds discussing the extraction procedures and the analytical techniques employed for their characterization. Finally, information about the different biological activities of these compounds has been also provided. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. 100 years of superconductivity

    CERN Document Server

    Rogalla, Horst

    2011-01-01

    Even a hundred years after its discovery, superconductivity continues to bring us new surprises, from superconducting magnets used in MRI to quantum detectors in electronics. 100 Years of Superconductivity presents a comprehensive collection of topics on nearly all the subdisciplines of superconductivity. Tracing the historical developments in superconductivity, the book includes contributions from many pioneers who are responsible for important steps forward in the field.The text first discusses interesting stories of the discovery and gradual progress of theory and experimentation. Emphasizi

  1. Superconducting accelerator technology

    International Nuclear Information System (INIS)

    Grunder, H.A.; Hartline, B.K.

    1986-01-01

    Modern and future accelerators for high energy and nuclear physics rely increasingly on superconducting components to achieve the required magnetic fields and accelerating fields. This paper presents a practical overview of the phenomenon of superconductivity, and describes the design issues and solutions associated with superconducting magnets and superconducting rf acceleration structures. Further development and application of superconducting components promises increased accelerator performance at reduced electric power cost

  2. EFFECT OF REMOVING OLEORESIN WITH VARIOUS CHEMICAL COMPOUNDS ON PHYSICAL AND MECHANICAL PROPERTIES OF KERUING WOOD (DIPTEROCARPUS SPP.

    Directory of Open Access Journals (Sweden)

    Bambang Wiyono

    2007-03-01

    Full Text Available Keruing  (Dipterocarpus spp.  was  the  second  important  wood  export of   Indonesia. Unfortunately, this wood contains oleoresin that hinders its utilization. Currently, the method used to remove oleoresin from keruing is by soaking it into bollied sodium salt solution. Result of  this method is unsatisfactory because the residual heavy oleoresin might still appear on the wood surface. The study was conducted to determine suitable chemical compounds for removing oleoresin from keruing, and the effects on physical and mechanical properties of the wood. Four types of chemical compounds were tested, i.e. sodium chloride, oxalic acid, sulfuric acid, and nitric acid, each at the concentrations of  0.5 percent, 1.0 percent, and 1.5 percent. Wood samples were soaked in the boiling solution at different concentration level for seven hours. When the solution cooled down, the oleoresin exudated out of  the wood samples was separated. The oleoresin was weighed for recovery determination after air dried, and the wood samples were cut into smaller-sized specimens for the physical and mechanical testing (MOE, MOR, compression parallel to grain, hardness and density. Results showed that sulfuric acid was the best chemical compound for removing oleoresin, and the higher the concentration the greater the oleoresin recovery. The second best chemical compound was nitric acid at an optimum concentration of one percent. The soaking of keruing in sulfuric acid and oxalic acid solution resulted in paler wood color compare with the untreated wood sample. Nitric acid solutions caused the color of the wood surface to turn into yellow brownish. The physical and mechanical properties (MOE, MOR, compression parallel to grain, hardness and density of the oleoresin-removed keruing were slightly lower than the untreated (control samples.

  3. Physico-Chemical Characterization, Bioactive Compounds and Antioxidant Activity of Malay Apple [Syzygium malaccense (L.) Merr. & L.M. Perry

    OpenAIRE

    Nunes, Polyana Campos; Aquino, Jailane de Souza; Rockenbach, Ismael Ivan; Stamford, T?nia L?cia Montenegro

    2016-01-01

    The purpose of this study was to evaluate the physico-chemical characteristics, bioactive compounds and antioxidant activity of Malay apple fruit (Syzygium malaccense) grown in Brazil with regard to the geographical origin and its peel fractions and edible portion analyzed independently. Fruit diameter, weight, yield, and centesimal composition, ascorbic acid, reductive sugars, total soluble solids, pH and fiber content were determined. Total phenolics (1293 mg gallic acid equivalent/100 g) a...

  4. Drug discovery for hearing loss: Phenotypic screening of chemical compounds on primary cultures of the spiral ganglion.

    Science.gov (United States)

    Whitlon, Donna S

    2017-06-01

    In the United States there are, at present, no drugs that are specifically FDA approved to treat hearing loss. Although several clinical trials are ongoing, including one testing D-methionine that is supported by the US Army, none of these trials directly address the effect of noise exposure on cochlear spiral ganglion neurons. We recently published the first report of a systematic chemical compound screen using primary, mammalian spiral ganglion cultures in which we were able to detect a compound and others in its class that increased neurite elongation, a critical step in restoring cochlear synapses after noise induced hearing loss. Here we discuss the issues, both pro and con, that influenced the development of our approach. These considerations may be useful for future compound screens that target the same or other attributes of cochlear spiral ganglion neurons. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Unified explanation of chemical ordering, the Slater-Pauling rule, and half-metallicity in full Heusler compounds

    Science.gov (United States)

    Faleev, Sergey V.; Ferrante, Yari; Jeong, Jaewoo; Samant, Mahesh G.; Jones, Barbara; Parkin, Stuart S. P.

    2017-01-01

    In the present work we developed an orbital coupling model for cubic full Heusler compounds that provides a unified set of rules that account for the chemical ordering, magnetic moment, and composition of the most promising candidates for half-metallicity. The origin and limitations of the rules are clearly described. To the best of our knowledge all of the several dozen half-metallic Heusler compounds known in the literature that follow the Mt=Nt-24 or Mt=Nt-28 generalized Slater-Pauling behavior satisfy the derived half-metallicity rule. Calculations performed by using density functional theory—performed for 259 compounds—confirm the validity of our model and derived rules for broad classes of Heusler compounds.

  6. Valence skipping driven superconductivity and charge Kondo effect

    International Nuclear Information System (INIS)

    Yanagisawa, Takashi; Hase, Izumi

    2013-01-01

    Highlights: •Valence skipping in metallic compounds can give rise to an unconventional superconductivity. •Several elements in the periodic table show valence skipping (or valence missing), for example, Bi forms the compounds in valence states +3 and +5. •The doping of valence skipping elements will induce superconductivity and this will lead to a possibility of high temperature superconductivity. •We consider the Wolf model with negative-U impurities, and show a phase diagram including superconducting phase. •There is a high temperature region near the boundary. -- Abstract: Valence skipping in metallic compounds can give rise to an unconventional superconductivity. Several elements in the periodic table show valence skipping (or valence missing), for example, Bi forms the compounds in valence states +3 and +5. The doping of valence skipping elements will induce superconductivity and this will lead to a possibility of high temperature superconductivity. We consider the Wolf model with negative-U impurities, and show a phase diagram including superconducting phase. The superconducting state is changed into a metallic state with a local singlet as the attractive interaction |U| increases. There is a high temperature region near the boundary

  7. Sulfonamides identified as plant immune-priming compounds in high-throughput chemical screening increase disease resistance in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Yoshiteru eNoutoshi

    2012-10-01

    Full Text Available Plant activators are agrochemicals that protect crops from diseases by activating the plant immune system. To isolate lead compounds for use as practical plant activators, we screened 2 different chemical libraries composed of various bioactive substances by using an established screening procedure that can selectively identify immune-priming compounds. We identified and characterized a group of sulfonamide compounds—sulfameter, sulfamethoxypyridazine, sulfabenzamide, and sulfachloropyridazine—among the various isolated candidate molecules. These sulfonamide compounds enhanced the avirulent Pseudomonas-induced cell death of Arabidopsis suspension cell cultures and increased disease resistance in Arabidopsis plants against both avirulent and virulent strains of the bacterium. These compounds did not prevent the growth of pathogenic bacteria in minimal liquid media at 200 µM. They also did not induce the expression of defense-related genes in Arabidopsis seedlings, at least not at 24 and 48 h after treatment, suggesting that they do not act as salicylic acid analogs. In addition, although sulfonamides are known to be folate biosynthesis inhibitors, the application of folate did not restore the potentiation effects of the sulfonamides on pathogen-induced cell death. Our data suggest that sulfonamides potentiate Arabidopsis disease resistance by their novel chemical properties.

  8. Superconducting Dy1-x(Gd,Yb)xBa2Cu3O7-δ thin films made by Chemical Solution Deposition

    DEFF Research Database (Denmark)

    Opata, Yuri Aparecido; Wulff, Anders Christian; Hansen, Jørn Otto Bindslev

    2016-01-01

    Dy1-x(Gd or Yb)xBa2Cu3O7-δ samples were prepared using chemical solution deposition (CSD), based on trifluoroacetate metal-organic decomposition (MOD) methods. X-ray diffraction results demonstrated the formation of the RE123 superconducting phase with a strong in-plane and out-of-plane texture. c......-lattice constants were observed to decrease for all samples doped with Gd or Yb. Measurements of the onset critical transition temperature (Tonsetc ) were found to decrease with increasing Yb content, while only minor changes were observed for samples with Gd. Critical current density (Jc) analysis demonstrated...

  9. Phonon-mediated superconductivity in graphene by lithium deposition

    Science.gov (United States)

    Profeta, Gianni; Calandra, Matteo; Mauri, Francesco

    2012-02-01

    Graphene is the physical realization of many fundamental concepts and phenomena in solid-state physics. However, in the list of graphene's many remarkable properties, superconductivity is notably absent. If it were possible to find a way to induce superconductivity, it could improve the performance and enable more efficient integration of a variety of promising device concepts including nanoscale superconducting quantum interference devices, single-electron superconductor-quantum dot devices, nanometre-scale superconducting transistors and cryogenic solid-state coolers. To this end, we explore the possibility of inducing superconductivity in a graphene sheet by doping its surface with alkaline metal adatoms, in a manner analogous to which superconductivity is induced in graphite intercalated compounds (GICs). As for GICs, we find that the electrical characteristics of graphene are sensitive to the species of adatom used. However, contrary to what happens in GICs, Li-covered graphene is superconducting at a much higher temperature with respect to Ca-covered graphene.

  10. Ionization Potentials of Chemical Warfare Agents and Related Compounds Determined with Density Functional Theory

    National Research Council Canada - National Science Library

    Wright, J

    2000-01-01

    ...) agents at contaminated sites. Reported herein are theoretical ionization potentials for CW agents and their related compounds calculated using density functional theory at the B3LYP/6-311+G(2d,p) level of theory...

  11. Evaluation of performance reference compounds (PRCs) to monitor emerging polar contaminants by polar organic chemical integrative samplers (POCIS) in rivers.

    Science.gov (United States)

    Carpinteiro, Inmaculada; Schopfer, Adrien; Estoppey, Nicolas; Fong, Camille; Grandjean, Dominique; de Alencastro, Luiz F

    2016-02-01

    In this work, a method combining polar organic chemical integrative samplers (POCIS) and ultraperformance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) was assessed for the determination of two corrosion inhibitors (benzotriazole and methylbenzotriazole), seven pesticides (atrazine, diuron, isoproturon, linuron, metolachlor, penconazole, terbuthylazine), and four pharmaceuticals (carbamazepine, diclofenac, metformin, sulfamethoxazole) in river water. As a first step, two POCIS sorbents, hydrophilic-lipophilic balance (HLB) and Strata X-CW, were compared. The comparison of the uptake profiles of the studied compounds showed that the HLB sorbent provides better uptake (higher sampled amount and better linearity) than Strata X-CW except for the basic compound metformin. Since the sampling rate (R s) of POCIS depends on environmental factors, seven compounds were evaluated as potential performance reference compounds (PRCs) through kinetic experiments. Deisopropylatrazine-d5 (DIA-d5) and, as far as we know, for the first time 4-methylbenzotriazole-d3 showed suitable desorption. The efficiency of both compounds to correct for the effect of water velocity was shown using a channel system in which POCIS were exposed to 2 and 50 cm s(-1). Finally, POCIS were deployed upstream and downstream of agricultural wine-growing and tree-growing areas in the Lienne River and the Uvrier Canal (Switzerland). The impact of the studied areas on both streams could be demonstrated.

  12. Studies on chemical phenomena of high concentration tritium water and organic compounds of tritium from viewpoint of the tritium confinement

    International Nuclear Information System (INIS)

    Yamanishi, Toshihiko; Hayashi, Takumi; Iwai, Yasunori; Isobe, Kanetsugu; Hara, Masanori; Sugiyama, Takahiko; Okuno, Kenji

    2009-01-01

    As a part of the grant-in-aid for scientific research on priority areas entitled 'frontiers of tritium researches toward fusion reactors', coordinated two research programs on chemical phenomena of high concentration tritium water and organic compounds of tritium from view point of the tritium confinement have been conducted by the C01 team. The results are summarized as follows: (1) Chemical effects of the high concentration tritium water on stainless steels as structural materials of fusion reactors were investigated. Basic data on tritium behaviors at the metal-water interface and corrosion of metal in tritium water were obtained. (2) Development of the tritium confinement and extraction system for the circulating cooling water in the fusion reactor was studied. Improvement was obtained in the performance of a chemical exchange column and catalysts as major components of the water processing system. (J.P.N.)

  13. Acute toxicity of sea-dumped chemical munitions: Luminating the environmental toxicity of legacy compounds

    DEFF Research Database (Denmark)

    Mohammed Abdullah Christensen, Ilias; Sanderson, Hans; Baatrup, Erik

    2016-01-01

    As a result of the disarmament of Germany after the Second World War, 65,000 tons of chemical munitions were dumped in the Baltic Sea. Approximately 13,000 tons containing chemical warfare agents (CWAs) of which 11,000 tons were dumped in the Bornholm Basin east of Bornholm. This paper addresses...

  14. Developing Quantum Chemical and Polyparameter Models for Predicting Environmentally Significant Parameters for New Munition Compounds

    Science.gov (United States)

    2017-05-31

    solute partition coefficient between two phases, K, for the changes in molecular interaction energies involved in transferring a chemical between the...Office of chemical safety and pollution prevention. Washington, D.C: US EPA. 2012. 46. American Society for Testing and Materials. E1963 − 09: Standard...

  15. Coexistence of antiferromagnetism and superconductivity in heavy fermion cerium compound Ce.sub.3./sub.PdIn.sub.11./sub

    Czech Academy of Sciences Publication Activity Database

    Kratochvílová, M.; Prokleška, J.; Uhlířová, K.; Tkáč, V.; Dušek, Michal; Sechovský, V.; Custers, J.

    2015-01-01

    Roč. 5, Oct (2015), s. 15904 ISSN 2045-2322 R&D Projects: GA ČR(CZ) GAP204/11/0809 Institutional support: RVO:68378271 Keywords : crystal structure * magnetic transition * heavy fermion compounds * antiferromagnetism Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.228, year: 2015

  16. Development of magnetic order in superconducting systems

    International Nuclear Information System (INIS)

    Moncton, D.E.; Shirane, G.; Thomlinson, W.

    1979-08-01

    Two different classes of rare-earth (RE) ternary superconductors (RERh 4 B 4 and REMo 6 S 8 , X=S, Se) have provided the first instances in which chemically ordered sublattices of magnetic ions exist in superconductors. Neutron scattering studies show that simple, conventional antiferromagnetism coexists with superconductivity in a number of systems, while destruction of superconductivity occurs with the onset of ferromagnetism. The magnetic structural details are summarized for the coexistent antiferromagnets, and review measurements on the superconducting → ferromagnetic transition in ErRh 4 B 4

  17. Technetium compounds and their field of application

    International Nuclear Information System (INIS)

    Zaitseva, L.L.; Velichko, A.V.; Vinogradov, I.V.

    1988-02-01

    This chapter reviews the different applications of technetium and technetium compounds in catalysis, corrosion inhibition, superconductivity of technetium alloys, diagnostic techniques, radioisotope generators and radiopharmaceuticals. 649 refs [fr

  18. [Pollution status of phenolic compounds in the soil and sediment from a chemical industrial park along the Yangtze River].

    Science.gov (United States)

    Chen, Jiexia; Wei, Enze; Xian, Qiming

    2014-08-01

    A determination method of 12 phenolic compounds in soil and sediment samples by gas chromatography-mass spectrometry (GC-MS) analysis coupled with accelerated solvent extraction (ASE) and gel permeation chromatography (GPC) for clean-up was developed. The method detection limits (MDLs) varied from 0. 410 μg/kg to 13. 1 μg/kg (dry weight), and the average recoveries ranged from 70. 7% to 122% with the relative standard deviations (RSDs) of 1. 2% to 16%. Based on this method, the levels of 12 phenolic compounds were investigated in 17 soil surrounding a chemical industrial park along the Yangtze River and seven sediment samples collected in the river. It was found that 11 of the 12 phenolic compounds were detected in all of the 24 samples, and only hydroquinone was below the MDL. The contents of the total 12 phenolic compounds were 10. 16-30. 66 mg/kg in the soil and 18. 00-29. 83 mg/kg in the sediment, with the average contents of 18. 26 and 22. 51 mg/kg respectively. It showed that 4-nitro- phenol, 4-chloro-3-methylphenol, 2-chlorohydroquinone, 2-methyl-4,6-dinitrophenol and 2,4,6- trichlorophenol were five major phenolic contaminants in the soil and sediment in this study. The pollution levels of the 12 phenolic compounds were low in the soil of the chemical industrial park as well as in the sediment of the Yangtze River, which implied a comparatively low risk for the environment.

  19. Identification of three classes of heteroaromatic compounds with activity against intracellular Trypanosoma cruzi by chemical library screening.

    Directory of Open Access Journals (Sweden)

    Esther Bettiol

    Full Text Available The development of new drugs against Chagas disease is a priority since the currently available medicines have toxic effects, partial efficacy and are targeted against the acute phase of disease. At present, there is no drug to treat the chronic stage. In this study, we have optimized a whole cell-based assay for high throughput screening of compounds that inhibit infection of mammalian cells by Trypanosoma cruzi trypomastigotes. A 2000-compound chemical library was screened using a recombinant T. cruzi (Tulahuen strain expressing beta-galactosidase. Three hits were selected for their high activity against T. cruzi and low toxicity to host cells in vitro: PCH1, NT1 and CX1 (IC(50: 54, 190 and 23 nM, respectively. Each of these three compounds presents a different mechanism of action on intracellular proliferation of T. cruzi amastigotes. CX1 shows strong trypanocidal activity, an essential characteristic for the development of drugs against the chronic stage of Chagas disease where parasites are found intracellular in a quiescent stage. NT1 has a trypanostatic effect, while PCH1 affects parasite division. The three compounds also show high activity against intracellular T. cruzi from the Y strain and against the related kinetoplastid species Leishmania major and L. amazonensis. Characterization of the anti-T. cruzi activity of molecules chemically related to the three library hits allowed the selection of two compounds with IC(50 values of 2 nM (PCH6 and CX2. These values are approximately 100 times lower than those of the medicines used in patients against T. cruzi. These results provide new candidate molecules for the development of treatments against Chagas disease and leishmaniasis.

  20. Investigation of the chemical identity of soluble organophosphorus compounds found in natural waters. Research report

    International Nuclear Information System (INIS)

    Minear, R.A.

    1978-04-01

    Four algal species (Chlamydomonas reinhardtii, Chlorella pyrenoidosa, Anacystis nidulans, and Anabaena flos-aquae) were grown in batch culture on 32 P labelled media to yield dissolved organic phosphorus (DOP) compounds containing a radioactive tag. The DOP compounds of filtered culture solutions were characterized by Sephadex gel filtration and thin layer chromatography (TLC) as a function of culture age. Additional TLC of individual Sephadex fractions was conducted. Time, culture and known compounds (inositol mono- and hexaphosphate) comparisons were made. High performance liquid chromatography was used to separate inositol mono- and hexaphosphates and to compare the DOP components of one algal species (C. reinhardtii) with inositol phosphates. Combinations of alkaline bromination and Sephadex pretreatment were examined

  1. Determinants of the Sensory Quality of Półgęsek in Relation to Volatile Compounds and Chemical Composition

    Directory of Open Access Journals (Sweden)

    Nowicka Katarzyna

    2017-12-01

    Full Text Available The objective of this study was to determine the sensory quality of a specific Polish traditional product made from cured and then smoked goose meat (półgęsek in relation to its volatile compounds and chemical composition. In general, the examined samples contained 66.2% water, 12.2% fat, 17.9% protein, 1.8% connective tissue, and 2.3% NaCl. Moreover, 47 volatile compounds were identified and quantified. The typical decomposition products derived from lipid oxidation, amino acid degradation, carbohydrate fermentation and microbial esterification were the main volatiles detected in all the samples. The volatiles generated by the smoking process and the ones originating from spices were also observed. The results of the sensory evaluation indicated that all the samples of the analyzed products were characterized by a high overall quality. Results of the Principal Component Analysis (PCA showed, however, that specific groups of products have their own unique sensory profile. Additionally, the sensory analysis confirmed the significant role of the chemical composition and volatile compounds in the development of the overall quality of półgęsek.

  2. Compound forming extractants, solvating solvents and inert solvents IUPAC chemical data series

    CERN Document Server

    Marcus, Y; Kertes, A S

    2013-01-01

    Equilibrium Constants of Liquid-Liquid Distribution Reactions, Part III: Compound Forming Extractants, Solvating Solvents, and Inert Solvents focuses on the compilation of equilibrium constants of various compounds, such as acids, ions, salts, and aqueous solutions. The manuscript presents tables that show the distribution reactions of carboxylic and sulfonic acid extractants and their dimerization and other reactions in the organic phase and extraction reactions of metal ions from aqueous solutions. The book also states that the inorganic anions in these solutions are irrelevant, since they d

  3. Estimation of Physical Properties and Chemical Reactivity Parameters of Organic Compounds for Environmental Modeling by SPARC

    Science.gov (United States)

    Mathematical models for predicting the transport and fate of pollutants in the environment require reactivity parameter values that is value of the physical and chemical constants that govern reactivity. Although empirical structure activity relationships have been developed th...

  4. Organic compounds as corrosion inhibitors for mild steel in acidic media: correlation between inhibition efficiency and chemical structure

    Energy Technology Data Exchange (ETDEWEB)

    Elias, Elizandra C.S.; Chrisman, Erika C.A.N. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Escola de Quimica

    2009-12-19

    The use of inhibitors for mild steels corrosion control which are in contact with aggressive environment is an accepted practice in acid treatment of oil-wells. Organic compounds have been studied to evaluate their corrosion inhibition potential. Film-forming corrosion inhibitors, commonly used to protect oil-field equipment, can be absorbed on the steel surface to give structurally ordered layers. Therefore, the electrons should act as an important role for this adsorption. Studies reveal that organic compounds show significant inhibition efficiency. For this purpose, their molecules should contain N, O and S heteroatoms in various functional groups, long hydrocarbon linear or branched radical and anion and cation active components. However, most of these compounds are not only expensive but also toxic to living beings. According to the 'Green Chemistry' rules, corrosion inhibitors based on organic compounds should be cheap, with low toxicity and have high inhibition efficiency. In this study, the effects of some organic compounds with different groups such as amide, ether, phenyldiamine, anime and aminophenol on the corrosion behavior of mild steel in acidic media have been investigated. The experimental data were obtained by gravimetric measurements. The results show that these compounds reveal a promising corrosion inhibition where phenyldiamine is the most efficient. The effect of molecular structure on the corrosion inhibition efficiency was investigated by semi-empirical quantum chemical calculations. The electronic properties such as highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) energy levels, and LUMO-HOMO energy gap orbital density were calculated. The relations between the inhibition efficiency and some quantum parameters are discussed and correlations are proposed. The highest values for the HOMO densities were found in the vicinity nitrogen atom, indicating that it is the most probable adsorption center

  5. Some regularities in the occurrence of superconductivity

    International Nuclear Information System (INIS)

    Chapnik, I.M.

    1984-01-01

    The superconducting transition temperatures T/sub c/ of the non-transition elements (NTE) of the first long period of the Periodic Table are compared with those of analogous compounds having NTE components from the second period. In contrast to relations for transition metals (TM) the NTE compounds show a higher T/sub c/ if the NTE component belongs to the first long period. The intermetallic compounds, crystal lattices, and T/sub c/ are listed and discussed

  6. Chemical probes of quorum sensing: from compound development to biological discovery

    Science.gov (United States)

    Welsh, Michael A.; Blackwell, Helen E.

    2016-01-01

    Bacteria can utilize chemical signals to coordinate the expression of group-beneficial behaviors in a method of cell–cell communication called quorum sensing (QS). The discovery that QS controls the production of virulence factors and biofilm formation in many common pathogens has driven an explosion of research aimed at both deepening our fundamental understanding of these regulatory networks and developing chemical agents that can attenuate QS signaling. The inherently chemical nature of QS makes studying these pathways with small molecule tools a complementary approach to traditional microbiology techniques. Indeed, chemical tools are beginning to yield new insights into QS regulation and provide novel strategies to inhibit QS. Here, we review the most recent advances in the development of chemical probes of QS systems in Gram-negative bacteria, with an emphasis on the opportunistic pathogen Pseudomonas aeruginosa. We first describe reports of novel small molecule modulators of QS receptors and QS signal synthases. Next, in several case studies, we showcase how chemical tools have been deployed to reveal new knowledge of QS biology and outline lessons for how researchers might best target QS to combat bacterial virulence. To close, we detail the outstanding challenges in the field and suggest strategies to overcome these issues. PMID:27268906

  7. Sorption and toxicity reduction of pharmaceutically active compounds and endocrine disrupting chemicals in the presence of colloidal humic acid.

    Science.gov (United States)

    Kim, Injeong; Kim, Hyo-Dong; Jeong, Tae-Yong; Kim, Sang Don

    This study investigated the toxicity changes and sorption of pharmaceuticals and endocrine disrupters in the presence of humic acid (HA). For the sorption experiment, a dead end filtration (DEF) system was used to separate bound and free-form target compounds. An algae growth inhibition test and E-screen assay were conducted to estimate the toxic effect of pharmaceutically active compounds (PhACs) and endocrine disrupting chemicals (EDCs), respectively. The permeate concentration was confirmed using liquid chromatography-mass spectrometry. In the sorption test, we observed significant sorption of PhACs and EDCs on colloidal HA, except for sulfamethoxazole (SMX). The values of log KCOC derived from DEF determinations ranged from 4.40 to 5.03. The removal efficiency varied with the HA concentration and the target chemical properties. Tetracycline and 4-octylphenol showed the highest sorption or removal efficiency (≈50%), even at 5 mg C/L HA. The algal growth inhibition of PhACs and the estrogenic effects of EDCs were significantly decreased in proportion to HA concentrations, except for SMX. In addition, the chemical analysis results showed a positive relationship with the bioassay results. Consequently, the sorption of PhACs and EDCs onto colloidal HA should be emphasized in natural environments because it significantly reduces bioavailable concentrations and toxicity to aquatic organisms.

  8. Bark as potential source of chemical substances for industry: analysis of content of selected phenolic compounds

    Czech Academy of Sciences Publication Activity Database

    Maršík, Petr; Kotyza, Jan; Rezek, Jan; Vaněk, Tomáš

    -, č. 1 (2013), s. 4-9 ISSN 1804-0195 R&D Projects: GA MŠk(CZ) OC10026 Institutional research plan: CEZ:AV0Z50380511 Keywords : bark * extraction * phenolic compounds Subject RIV: EI - Biotechnology ; Bionics http://www.wasteforum.cz/cisla/WF_1_2013.pdf#page=4

  9. ISOTOPIC (14C) AND CHEMICAL COMPOSITION OF ATMOSPHERIC VOLATILE ORGANIC COMPOUND FRACTIONS - PRECURSORS TO OZONE FORMATION

    Science.gov (United States)

    Atmospheric volatile organic compounds (VOCs) are an important factor in the production of ozone near ground level [3]. Many hydrocarbons originate from auto exhaust. However, a number of VOCs, e.g., isoprene, are known to be natural in origin. To develop reliable models for un...

  10. Chemical characterization of bioactive compounds from the endophytic fungus Diaporthe helianthi isolated from Luehea divaricata

    Directory of Open Access Journals (Sweden)

    Vânia Specian

    2012-09-01

    Full Text Available Endophytic microorganisms, defined as fungi or bacteria that colonize the interior of plants without causing any immediate negative effects or damages, have reciprocal relationships with host plants. In some cases their presence is beneficial to the host due to the synthesis of bioactive compounds, among which several alcohols, esters, ketones and others that may react with other compounds and may be lethal to pathogenic microorganisms. Diaporthe helianthi (Phomopsis helianthi in its anamorphic phase is available worldwide, especially in Europe, Asia and America. Isolated in Europe as an agent of the sunflower stem cancer, it has also been endophytically isolated from tropical and temperate plants. A D. helianthi strain isolated from Luehea divaricata has been employed in current research. An investigation of the secondary metabolite from D. helianthi by CC and NMR of ¹H and 13C yielded the separation of 10 fractions and the identification of the phenolic compound 2(-4 hydroxyphenyl-ethanol (Tyrosol. Its antimicrobial reaction was tested and the ensuing antagonistic effects on the human pathogenic bacteria Enterococcus hirae, Escherichia coli, Micrococcus luteus, Salmonella typhi, Staphylococcus aureus, phytopathogenic Xanthomonas asc. phaseoli and phytopathogenic fungi were demonstrated. Results show that bioactive compounds and Tyrosol produced by D. helianthi have a biotechnological potential.

  11. Passive sampling in regulatory chemical monitoring of nonpolar organic compounds in the aquatic environment

    NARCIS (Netherlands)

    Booij, K.; Robinson, C.D.; Burgess, R.M.; Mayer, P.; Roberts, C.A.; Ahrens, L.; Allan, I.J.; Brant, J.; Jones, L.; Kraus, U.R.; Larsen, M.M.; Lepom, P.; Petersen, J.; Pröfrock, D.; Roose, P.; Schäfer, S.; Smedes, F.; Tixier, C.; Vorkamp, K.; Whitehouse, P.

    2016-01-01

    We reviewed compliance monitoring requirements in the EuropeanUnion, the United States, and the Oslo-Paris Convention for the protection of themarine environment of the North-East Atlantic, and evaluated if these are met bypassive sampling methods for nonpolar compounds. The strengths

  12. Ordering chemical compounds by their chronic toxicity to aquatic species. A principal component analysis

    NARCIS (Netherlands)

    Wal JT van der; Vaal MA; Hoekstra JA; Hermens JLM; ECO; RITOX

    1995-01-01

    This report is part of a project studying the variation in the sensitivity of species to toxicant's. Patterns in the chronic toxicity of compounds to aquatic species are studied using a multivariate statistical technique called principal componant analysis. The matrix consists of 15 aquatic species

  13. Graphic representation of 13C-nuclear magnetic resonance chemical shifts of oxygen-containing organosulfur compounds and its application to the structural analysis

    International Nuclear Information System (INIS)

    Sato, Soei; Nagata, Chikakiyo; Tanaka, Shigeyuki.

    1985-01-01

    A new method for the structural analysis of oxygen-containing organosulfur compounds was examined by 13 C-NMR spectroscopy. The 13 C-NMR spectra were measured for organosulfur compounds of various types such as sulfoxides, sulfones, sulfinic acids, sulfonyl chlorides, sulfonic acids and their salts, sulfuric acid ester compounds and sultam derivatives containing alkyl, alkenyl, alkinyl and aromatic ring groups. The spectra collected from literatures were also used. The 13 C-chemical shifts of α-carbon adjacent to sulfur atom in organosulfur compounds were classified according to the structural types of the compounds and classes of carbon atoms of alkane(CH 3 , CH 2 , > CH-, etc.), alkene, aromatic ring types. The graphic representation for these data was carried out in view of the structural analysis of these compounds. The chemical shifts for α-carbon of oxygen-containing organosulfur compounds were observed at lower-field range than that of sulfide and disulfide compounds. The chemical shifts of α-carbon are gradually shifted to lower-field in order of methyl, methylene, methyne and quaternary carbons. The chemical shifts of α-carbons were also affected by the adjacent groups and their structural types. Detailed graphic representations including adjacent groups were made for a series of compounds which have many kinds of β-groups. This method was succesfully applied to the structural analysis of a textile and polymer additive. (J.P.N.)

  14. WORKSHOPS: Radiofrequency superconductivity

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    In the continual push towards higher energy particle beams, superconducting radiofrequency techniques now play a vital role, highlighted in the fifth workshop on radiofrequency superconductivity, held at DESY from 19 - 24 August 1991

  15. Influence of UF4 physico-chemical properties on the assessment of the chronic exposure to this compound

    International Nuclear Information System (INIS)

    Ansoborlo, E.; Chalabreysse, J.

    1990-01-01

    A method was developed in order to assess uranium exposure hazards at work stations based on the industrial experience acquired by Comurhex Malvesi at Narbonne. Applied to uranium tetrafluoride (UF 4 ) the method involves 4 steps: 1. characterization of the industrial compound, including its physico-chemical properties (density, surface area, X-ray spectrum and uranium enrichment); 2. assessment of work station concentrations and particle size distribution (AMAD); 3. In vitro biological solubility with different synthetic fluids such as Gamble solutions with different gases or compounds added (oxygen or superoxide ions O 2 - ) in order to determine the solubility class D, W or Y; 4. workers' monitoring by routine measurements of urinary excretion completed, if necessary, by fecal excretion and γ-spectrometry. Results and present data on UF 4 are presented. 3 tabs., 4 figs [fr

  16. Characterizing the Smell of Marijuana by Odor Impact of Volatile Compounds: An Application of Simultaneous Chemical and Sensory Analysis.

    Directory of Open Access Journals (Sweden)

    Somchai Rice

    Full Text Available Recent U.S. legislation permitting recreational use of marijuana in certain states brings the use of marijuana odor as probable cause for search and seizure to the forefront of forensic science, once again. This study showed the use of solid-phase microextraction with multidimensional gas chromatography--mass spectrometry and simultaneous human olfaction to characterize the total aroma of marijuana. The application of odor activity analysis offers an explanation as to why high volatile chemical concentration does not equate to most potent odor impact of a certain compound. This suggests that more attention should be focused on highly odorous compounds typically present in low concentrations, such as nonanal, decanol, o-cymene, benzaldehyde, which have more potent odor impact than previously reported marijuana headspace volatiles.

  17. Assessing the sensitivity of benzene cluster cation chemical ionization mass spectrometry toward a wide array of biogenic volatile organic compounds

    Science.gov (United States)

    Lavi, Avi; Vermeuel, Michael; Novak, Gordon; Bertram, Timothy

    2017-04-01

    Chemical ionization mass spectrometry is a real-time, sensitive and selective measurement technique for the detection of volatile organic compounds (VOCs). The benefits of CIMS technology make it highly suitable for field measurements that requires fast (10Hz and higher) response rates, such as the study of surface-atmosphere exchange processes by the eddy covariance method. The use of benzene cluster cations as a regent ion was previously demonstrated as a sensitive and selective method for the detection of select biogenic VOCs (e.g. isoprene, monoterpenes and sesquiterpenes) [Kim et al., 2016; Leibrock and Huey, 2000]. Quantitative analysis of atmospheric trace gases necessitates calibration for each analyte as a function of atmospheric conditions. We describe a custom designed calibration system, based on liquid evaporation, for determination of the sensitivity of the benzene-CIMS to a wide range of organic compounds at atmospherically relevant mixing ratios (reactions and the role of water vapor and oxygen, we compare our measured sensitivities with a computational analysis of the charge distribution between the analyte, reagent ion and water molecules in the gas phase. These parameters provide insight on the ionization mechanism and provide parameters for quantification of organic molecules measured during field campaigns. References Kim, M. J., M. C. Zoerb, N. R. Campbell, K. J. Zimmermann, B. W. Blomquist, B. J. Huebert, and T. H. Bertram (2016), Revisiting benzene cluster cations for the chemical ionization of dimethyl sulfide and select volatile organic compounds, Atmos Meas Tech, 9(4), 1473-1484, doi:10.5194/amt-9-1473-2016. Leibrock, E., and L. G. Huey (2000), Ion chemistry for the detection of isoprene and other volatile organic compounds in ambient air, Geophys Res Lett, 27(12), 1719-1722, doi:Doi 10.1029/1999gl010804.

  18. Chemical compounds from anthropogenic environment and immune evasion mechanisms: potential interactions

    Science.gov (United States)

    Kravchenko, Julia; Corsini, Emanuela; Williams, Marc A.; Decker, William; Manjili, Masoud H.; Otsuki, Takemi; Singh, Neetu; Al-Mulla, Faha; Al-Temaimi, Rabeah; Amedei, Amedeo; Colacci, Anna Maria; Vaccari, Monica; Mondello, Chiara; Scovassi, A. Ivana; Raju, Jayadev; Hamid, Roslida A.; Memeo, Lorenzo; Forte, Stefano; Roy, Rabindra; Woodrick, Jordan; Salem, Hosni K.; Ryan, Elizabeth P.; Brown, Dustin G.; Lowe, Leroy; Lyerly, H.Kim

    2015-01-01

    An increasing number of studies suggest an important role of host immunity as a barrier to tumor formation and progression. Complex mechanisms and multiple pathways are involved in evading innate and adaptive immune responses, with a broad spectrum of chemicals displaying the potential to adversely influence immunosurveillance. The evaluation of the cumulative effects of low-dose exposures from the occupational and natural environment, especially if multiple chemicals target the same gene(s) or pathway(s), is a challenge. We reviewed common environmental chemicals and discussed their potential effects on immunosurveillance. Our overarching objective was to review related signaling pathways influencing immune surveillance such as the pathways involving PI3K/Akt, chemokines, TGF-β, FAK, IGF-1, HIF-1α, IL-6, IL-1α, CTLA-4 and PD-1/PDL-1 could individually or collectively impact immunosurveillance. A number of chemicals that are common in the anthropogenic environment such as fungicides (maneb, fluoxastrobin and pyroclostrobin), herbicides (atrazine), insecticides (pyridaben and azamethiphos), the components of personal care products (triclosan and bisphenol A) and diethylhexylphthalate with pathways critical to tumor immunosurveillance. At this time, these chemicals are not recognized as human carcinogens; however, it is known that they these chemicalscan simultaneously persist in the environment and appear to have some potential interfere with the host immune response, therefore potentially contributing to promotion interacting with of immune evasion mechanisms, and promoting subsequent tumor growth and progression. PMID:26002081

  19. Optical chemical sensors for atmospheric pollutants based on nano porous materials: application to the formaldehyde and the other carbonyl compounds

    International Nuclear Information System (INIS)

    Paolacci, H.

    2006-12-01

    Formaldehyde, a well-identified indoor pollutant, was recently classified as carcinogenic. New regulations for the air quality are expected and therefore there is a need for low-cost sensors, sensitive and selective with a fast response time for the detection of formaldehyde at ppb level. In the present work, we had developed a chemical sensor based on nano-porous matrices doped with Fluoral-P and optical methods of detection. The nano-porous matrices, elaborated via the Sol-Gel process, display nano-pores whose cavity is tailored for the trapping of the targeted pollutant. They provide a first selectivity with the discrimination of the pollutants by their size. A second selectivity is obtained with a molecular probe, Fluoral-P, which reacts specifically with formaldehyde leading to the 3,5- di-acetyl-1,4-dihydro-lutidine (DDL). The kinetics of formation of DDL was studied as function of many parameters such as the concentration of Fluoral-P in the matrix, the pollutant content in gas mixture, the flow rate, the relative humidity of the gas mixtures and interference with other carbonylated compounds. The present chemical sensor can detect, via absorbance measurements, 2 ppb of formaldehyde within 30 min over a O to 60% relative humidity range. Moreover, to detect the total carbonylated compounds, we also explored the potentiality of a chemical sensor using, as a probe molecule, the 2'4-dinitro-phenyl-hydrazine which forms with these compounds the corresponding hydrazones derivatives. A patent was deposited for these two sensors. We have also developed a semi-miniaturized prototype for demonstration, using a flow cell, a miniaturized spectrophotometer, a light source and a lap-top. (author)

  20. Stimulation of Ideas through Compound-Based Bibliometrics: Counting and Mapping Chemical Compounds for Analyzing Research Topics in Chemistry, Physics, and Materials Science

    Science.gov (United States)

    Barth, Andreas; Marx, Werner

    2012-01-01

    Counting compounds (rather than papers or citations) offers a new perspective for quantitative analyses of research activities. First of all, we can precisely define (compound-related) research topics and access the corresponding publications (scientific papers as well as patents) as a measure of research activity. We can also establish the time evolution of the publications dealing with specific compounds or compound classes. Moreover, the mapping of compounds by establishing compound-based landscapes has some potential to visualize the compound basis of research topics for further research activities. We have analyzed the rare earth compounds to give an example of a broad compound class. We present the number of the currently existing compounds and of the corresponding publications as well as the time evolution of the papers and patents. Furthermore, we have analyzed the rare earth cuprates (copper oxides) as an example of a narrower compound class to demonstrate the potential of mapping compounds by compound-based landscapes. We have quantified the various element combinations of the existing compounds and revealed all element combinations not yet realized in the synthesis within this compound class. Finally, we have analyzed the quasicrystal compound category as an example of a compound class that is not defined by a specific element combination or a molecular structure. PMID:24551517

  1. Stimulation of Ideas through Compound-Based Bibliometrics: Counting and Mapping Chemical Compounds for Analyzing Research Topics in Chemistry, Physics, and Materials Science.

    Science.gov (United States)

    Barth, Andreas; Marx, Werner

    2012-12-01

    Counting compounds (rather than papers or citations) offers a new perspective for quantitative analyses of research activities. First of all, we can precisely define (compound-related) research topics and access the corresponding publications (scientific papers as well as patents) as a measure of research activity. We can also establish the time evolution of the publications dealing with specific compounds or compound classes. Moreover, the mapping of compounds by establishing compound-based landscapes has some potential to visualize the compound basis of research topics for further research activities. We have analyzed the rare earth compounds to give an example of a broad compound class. We present the number of the currently existing compounds and of the corresponding publications as well as the time evolution of the papers and patents. Furthermore, we have analyzed the rare earth cuprates (copper oxides) as an example of a narrower compound class to demonstrate the potential of mapping compounds by compound-based landscapes. We have quantified the various element combinations of the existing compounds and revealed all element combinations not yet realized in the synthesis within this compound class. Finally, we have analyzed the quasicrystal compound category as an example of a compound class that is not defined by a specific element combination or a molecular structure.

  2. The role of mineral elements and other chemical compounds used in balneology: data from double-blind randomized clinical trials

    Science.gov (United States)

    Morer, Carla; Roques, Christian-François; Françon, Alain; Forestier, Romain; Maraver, Francisco

    2017-12-01

    The aims of this study were to conduct a systematic literature review on balneotherapy about the specific therapeutic role of mineral elements and other chemical compounds of mineral waters and derivate peloids/muds and to discuss the study methods used to evaluate it (in musculoskeletal conditions). We searched Medline by PubMed using the following key words: "spa therapy" "balneotherapy" "mud" "peloid" "mud pack Therapy" in combination with "randomized controlled trial" "double blind trial." We also reviewed the reference list of articles retrieved by the Medline search. We selected the double-blind randomized clinical trials that assessed the effects of mineral water or mud treatments compared to tap water, attenuated peloid/mud therapy or similar treatments without the specific minerals or chemical compounds of the treatment group ("non-mineral"). We evaluated the internal validity and the quality of the statistical analysis of these trials. The final selection comprised 27 double-blind randomized clinical trials, 20 related to rheumatology. A total of 1118 patients with rheumatological and other musculoskeletal diseases were evaluated in these studies: 552 of knee osteoarthritis, 47 of hand osteoarthritis, 147 chronic low back pain, 308 of reumathoid arthritis, and 64 of osteoporosis; 293 of these participants were assigned to the experimental groups of knee osteoarthritis, 24 in hand osteoarthritis, 82 of low back pain, 152 with reumathoid arthritis, and 32 with osteoporosis. They were treated with mineral water baths and/or mud/peloid (with or without other forms of treatment, like physical therapy, exercise…). The rest were allocated to the control groups; they received mainly tap water and/or "non-mineral" mud/peloid treatments. Mineral water or mud treatments had better and longer improvements in pain, function, quality of life, clinical parameters, and others in some rheumatologic diseases (knee and hand osteoarthritis, chronic low back pain

  3. Development of a general model for determination of thermal conductivity of liquid chemical compounds at atmospheric pressure

    DEFF Research Database (Denmark)

    Gharagheizi, Farhad; Ilani‐Kashkouli, Poorandokht; Sattari, Mehdi

    2013-01-01

    In this communication, a general model for representation/presentation of the liquid thermal conductivity of chemical compounds (mostly organic) at 1 atm pressure for temperatures below normal boiling point and at saturation pressure for temperatures above the normal boiling point is developed...... of the model comprise temperature, acentric factor, critical pressure, normal boiling temperature, and molecular weight. Nearly 80% of the data set (15,221 data) is randomly assigned to develop the model equation, 10% of the data set (1902 data) is used to validate the model, and the remaining data (1902 data...

  4. The role of mineral elements and other chemical compounds used in balneology: data from double-blind randomized clinical trials.

    Science.gov (United States)

    Morer, Carla; Roques, Christian-François; Françon, Alain; Forestier, Romain; Maraver, Francisco

    2017-12-01

    The aims of this study were to conduct a systematic literature review on balneotherapy about the specific therapeutic role of mineral elements and other chemical compounds of mineral waters and derivate peloids/muds and to discuss the study methods used to evaluate it (in musculoskeletal conditions). We searched Medline by PubMed using the following key words: "spa therapy" "balneotherapy" "mud" "peloid" "mud pack Therapy" in combination with "randomized controlled trial" "double blind trial." We also reviewed the reference list of articles retrieved by the Medline search. We selected the double-blind randomized clinical trials that assessed the effects of mineral water or mud treatments compared to tap water, attenuated peloid/mud therapy or similar treatments without the specific minerals or chemical compounds of the treatment group ("non-mineral"). We evaluated the internal validity and the quality of the statistical analysis of these trials. The final selection comprised 27 double-blind randomized clinical trials, 20 related to rheumatology. A total of 1118 patients with rheumatological and other musculoskeletal diseases were evaluated in these studies: 552 of knee osteoarthritis, 47 of hand osteoarthritis, 147 chronic low back pain, 308 of reumathoid arthritis, and 64 of osteoporosis; 293 of these participants were assigned to the experimental groups of knee osteoarthritis, 24 in hand osteoarthritis, 82 of low back pain, 152 with reumathoid arthritis, and 32 with osteoporosis. They were treated with mineral water baths and/or mud/peloid (with or without other forms of treatment, like physical therapy, exercise…). The rest were allocated to the control groups; they received mainly tap water and/or "non-mineral" mud/peloid treatments. Mineral water or mud treatments had better and longer improvements in pain, function, quality of life, clinical parameters, and others in some rheumatologic diseases (knee and hand osteoarthritis, chronic low back pain

  5. DNA-Encoded Chemical Libraries: A Selection System Based On Endowing Organic Compounds with Amplifiable Information.

    Science.gov (United States)

    Neri, Dario; Lerner, Richard A

    2018-01-12

    The discovery of organic ligands that bind specifically to proteins is a central problem in chemistry, biology, and the biomedical sciences. The encoding of individual organic molecules with distinctive DNA tags, serving as amplifiable identification bar codes, allows the construction and screening of combinatorial libraries of unprecedented size, thus facilitating the discovery of ligands to many different protein targets. Fundamentally, one links powers of genetics and chemical synthesis. After the initial description of DNA-encoded chemical libraries in 1992, several experimental embodiments of the technology have been reduced to practice. This review provides a historical account of important milestones in the development of DNA-encoded chemical libraries, a survey of relevant ongoing research activities, and a glimpse into the future. Expected final online publication date for the Annual Review of Biochemistry Volume 87 is June 20, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  6. Compendium of shock wave data. Section C. Organic compounds excluding hydrocarbons. Section D. Mixtures. Section E. Mixtures and solutions without chemical characterization. Compendium index

    International Nuclear Information System (INIS)

    van Thiel, M.; shaner, J.; Salinas, E.

    1977-06-01

    This volume lists thermodynamic data for organic compounds excluding hydrocarbons, mixtures, and mixtures and solutions without chemical characterization. Alloys and some minerals are included among the mixtures. This volume also contains the index for the three-volume compendium

  7. Simple Superconducting "Permanent" Electromagnet

    Science.gov (United States)

    Israelson, Ulf E.; Strayer, Donald M.

    1992-01-01

    Proposed short tube of high-temperature-superconducting material like YBa2Cu3O7 acts as strong electromagnet that flows as long as magnetic field remains below critical value and temperature of cylinder maintained sufficiently below superconducting-transition temperature. Design exploits maximally anisotropy of high-temperature-superconducting material.

  8. Antidepressant-like and anxiolytic-like effects of cannabidiol: a chemical compound of Cannabis sativa.

    Science.gov (United States)

    de Mello Schier, Alexandre R; de Oliveira Ribeiro, Natalia P; Coutinho, Danielle S; Machado, Sergio; Arias-Carrión, Oscar; Crippa, Jose A; Zuardi, Antonio W; Nardi, Antonio E; Silva, Adriana C

    2014-01-01

    Anxiety and depression are pathologies that affect human beings in many aspects of life, including social life, productivity and health. Cannabidiol (CBD) is a constituent non-psychotomimetic of Cannabis sativa with great psychiatric potential, including uses as an antidepressant-like and anxiolytic-like compound. The aim of this study is to review studies of animal models using CBD as an anxiolytic-like and antidepressant-like compound. Studies involving animal models, performing a variety of experiments on the above-mentioned disorders, such as the forced swimming test (FST), elevated plus maze (EPM) and Vogel conflict test (VCT), suggest that CBD exhibited an anti-anxiety and antidepressant effects in animal models discussed. Experiments with CBD demonstrated non-activation of neuroreceptors CB1 and CB2. Most of the studies demonstrated a good interaction between CBD and the 5-HT1A neuro-receptor.

  9. Toxic Compounds Analysis With High Performance Liquid Chromatography Detected By Electro Chemical Detector (Ecd)

    OpenAIRE

    Hideharu Shintaniq

    2014-01-01

    The principal area of application of high performance liquid chromatography-electrochemical detector (HPLC-ECD) has been in the analysis of naturally-occurring analytes, such as catecholamines, and pharmaceuticals in biological samples, HPLC-ECD has also applied to the analysis of pesticides and other analytes of interest to the toxicologist. In this paper, toxic area is described. In these, ammatoxins, aromatic amine, nitro-compounds, algal toxins, fungal toxins, pesticides, veterinary drug ...

  10. Quantitative detection of chemical compounds in human hair with coherent anti-Stokes Raman scattering microscopy

    OpenAIRE

    Zimmerley, Maxwell; Lin, Chia-Yu; Oertel, David C.; Marsh, Jennifer M.; Ward, Jimmie L.; Potma, Eric Olaf

    2009-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is used to determine the distribution and concentration of selected compounds in intact human hair. By generating images based on ratiometric CARS contrast, quantitative concentration maps of both water and externally applied d-glycine are produced in the cortex of human hair fibers. Both water and d-glycine are found to homogeneously distribute throughout the cortical regions of the hair. The ability to selectively detect molecular agen...

  11. Chemical composition, bioactive compounds, and volatiles of six table grape varieties (Vitis vinifera L.).

    Science.gov (United States)

    Aubert, Christophe; Chalot, Guillaume

    2018-02-01

    Six table grape cultivars (Centennial Seedless, Chasselas, Italia, Italia Rubi, Alphonse Lavallée, and Muscat de Hambourg) were analyzed for their levels of soluble solids, titratable acidity, sugars, organic acids, vitamin C and E, carotenoids, polyphenolics and volatile compounds during two successive years. Descriptive sensory analyses of the six table grape varieties were also performed. Mainly due to anthocyanins, black cultivars had the highest total phenolic contents. Alphonse Lavallée had also both the highest levels of trans-resveratrol and piceid, and Muscat de Hambourg the highest levels of α-tocopherol, β-carotene and monoterpenols, well-known key aroma compounds in Muscat varieties having also interesting pharmacological properties. This study shows that the two traditional black French cultivars, Muscat de Hambourg and Alphonse Lavallée, are particularly rich in bioactive compounds and have a great potential for human health. Finally, Muscat de Hambourg was significantly rated sweeter, juicier and more aromatic than the others cultivars. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Chemical oxidation of volatile and semi-volatile organic compounds in soil

    International Nuclear Information System (INIS)

    Gates, D.D.; Siegrist, R.L.; Cline, S.R.

    1995-01-01

    Subsurface contamination with fuel hydrocarbons or chlorinated hydrocarbons is prevalent throughout the Department of Energy (DOE) complex and in many sites managed by the Environmental Protection Agency (EPA) Superfund program. The most commonly reported chlorinated hydrocarbons (occurring > 50% of DOE contaminated sites) were trichloroethylene (TCE), 1, 1, 1,-trichloroethane (TCA), and tetrachloroethylene (PCE) with concentrations in the range of 0.2 μg/kg to 12,000 mg/kg. The fuel hydrocarbons most frequently reported as being present at DOE sites include aromatic compounds and polyaromatic compounds such as phenanthrene, pyrene, and naphthalene. The primary sources of these semi-volatile organic compounds (SVOCs) are coal waste from coal fired electric power plants used at many of these facilities in the past and gasoline spills and leaks. Dense non-aqueous phase liquids (DNAPLs) can migrate within the subsurface for long periods of time along a variety of pathways including fractures, macropores, and micropores. Diffusion of contaminants in the non-aqueous, aqueous, and vapor phase can occur from the fractures and macropores into the matrix of fine-textured media. As a result of these contamination processes, removal of contaminants from the subsurface and the delivery of treatment agents into and throughout contaminated regions are often hindered, making rapid and extensive remediation difficult

  13. Phenolic Compounds and Antioxidant Activity in Grape Juices: A Chemical and Sensory View

    Directory of Open Access Journals (Sweden)

    Fernanda Cosme

    2018-03-01

    Full Text Available The search for food products that promote health has grown over the years. Phenolic compounds present in grapes and in their derivatives, such as grape juices, represent today a broad area of research, given the benefits that they have on the human health. Grape juice can be produced from any grape variety once it has attained appropriate maturity. However, only in traditional wine producing regions, grape juices are produced from Vitis vinifera grape varieties. For example, Brazilian grape juices are essentially produced from Vitis labrusca grape varieties, known as American or hybrid, as they preserve their characteristics such as the natural flavour after pasteurisation. Grapes are one of the richest sources of phenolic compounds among fruits. Therefore, grape juices have been broadly studied due to their composition in phenolic compounds and their potential beneficial effects on human health, specifically the ability to prevent various diseases associated with oxidative stress, including cancers, cardiovascular and neurodegenerative diseases. Therefore, this review will address grape juices phenolic composition, with a special focus on the potential beneficial effects on human health and on the grape juice sensory impact.

  14. A method to estimate the enthalpy of formation of organic compounds with chemical accuracy

    DEFF Research Database (Denmark)

    Hukkerikar, Amol; Meier, Robert J.; Sin, Gürkan

    2013-01-01

    A model that yields chemical accuracy for a broad range of organic molecules is presented. The range of applicability of such an accurate model is very broad: it can be used by chemists to predict equilibria while fostering new chemistries and allow process engineers to make more reliable designs...

  15. Development of a QSAR for worst case estimates of acute toxicity of chemically reactive compounds

    NARCIS (Netherlands)

    Freidig, A.P.; Dekkers, S.; Verwei, M.; Zvinavashe, E.; Bessems, J.G.M.; Sandt, J.J.M. van de

    2007-01-01

    Future EU legislations enforce a fast hazard and risk assessment of thousands of existing chemicals. If conducted by means of present data requirements, this assessment will use a huge number of test animals and will be neither cost nor time effective. The purpose of the current research was to

  16. Chemical shift of U L3 edges in different uranium compounds ...

    Indian Academy of Sciences (India)

    Administrator

    same oxidation state of the metal ion, its X-ray absorption edge may appear at different energies in different materi- als, depending on the nature of ligands attached to the metal ion, coordination number, covalent character of the bond, electronegativity of the anion or in other words the chemical environment of the metal ion.

  17. Chemical compounds from anthropogenic environment and immune evasion mechanisms: potential interactions.

    Science.gov (United States)

    Kravchenko, Julia; Corsini, Emanuela; Williams, Marc A; Decker, William; Manjili, Masoud H; Otsuki, Takemi; Singh, Neetu; Al-Mulla, Faha; Al-Temaimi, Rabeah; Amedei, Amedeo; Colacci, Anna Maria; Vaccari, Monica; Mondello, Chiara; Scovassi, A Ivana; Raju, Jayadev; Hamid, Roslida A; Memeo, Lorenzo; Forte, Stefano; Roy, Rabindra; Woodrick, Jordan; Salem, Hosni K; Ryan, Elizabeth P; Brown, Dustin G; Bisson, William H; Lowe, Leroy; Lyerly, H Kim

    2015-06-01

    An increasing number of studies suggest an important role of host immunity as a barrier to tumor formation and progression. Complex mechanisms and multiple pathways are involved in evading innate and adaptive immune responses, with a broad spectrum of chemicals displaying the potential to adversely influence immunosurveillance. The evaluation of the cumulative effects of low-dose exposures from the occupational and natural environment, especially if multiple chemicals target the same gene(s) or pathway(s), is a challenge. We reviewed common environmental chemicals and discussed their potential effects on immunosurveillance. Our overarching objective was to review related signaling pathways influencing immune surveillance such as the pathways involving PI3K/Akt, chemokines, TGF-β, FAK, IGF-1, HIF-1α, IL-6, IL-1α, CTLA-4 and PD-1/PDL-1 could individually or collectively impact immunosurveillance. A number of chemicals that are common in the anthropogenic environment such as fungicides (maneb, fluoxastrobin and pyroclostrobin), herbicides (atrazine), insecticides (pyridaben and azamethiphos), the components of personal care products (triclosan and bisphenol A) and diethylhexylphthalate with pathways critical to tumor immunosurveillance. At this time, these chemicals are not recognized as human carcinogens; however, it is known that they these chemicalscan simultaneously persist in the environment and appear to have some potential interfere with the host immune response, therefore potentially contributing to promotion interacting with of immune evasion mechanisms, and promoting subsequent tumor growth and progression. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Superconductivity in Medicine

    Science.gov (United States)

    Alonso, Jose R.; Antaya, Timothy A.

    2012-01-01

    Superconductivity is playing an increasingly important role in advanced medical technologies. Compact superconducting cyclotrons are emerging as powerful tools for external beam therapy with protons and carbon ions, and offer advantages of cost and size reduction in isotope production as well. Superconducting magnets in isocentric gantries reduce their size and weight to practical proportions. In diagnostic imaging, superconducting magnets have been crucial for the successful clinical implementation of magnetic resonance imaging. This article introduces each of those areas and describes the role which superconductivity is playing in them.

  19. Lichens as a source of chemical compounds with anti-inflammatory activity

    Directory of Open Access Journals (Sweden)

    Studzińska-Sroka Elżbieta

    2018-03-01

    Full Text Available Symptoms of inflammation accompany a number of diseases. In order to mitigate them, folk medicine has used a variety of medicinal substances, including herbs and mushrooms. Lichens are less known organisms, containing specific secondary metabolites with interesting biological properties. One of their biological actions is the anti-inflammatory activity that has been confirmed by in vitro and animal studies. It has been proven that compounds and extracts from lichens inhibit the enzymes involved in the inflammatory process. The following paper is a review of research on the little-known anti-inflammatory properties of lichens.

  20. Application of Quantum Chemical Approximations to Environmental Problems: Prediction of Water Solubility for Nitro Compounds

    Science.gov (United States)

    2009-11-10

    the same study this method was adapted for solid at given temperature solutes and tested on drugs and pesticides . The intrinsic error of ca. 0.5 LU...the ∆Gfus and solubility values of 53 drugs and pesticides collected from the literature (28, 44, 45) plus five nitro compounds: TNB, TNT, 4-Am- 2,6...230–237. (12) Hawari, J.; Halasz, A.; Groom, C.; Deschamps, S.; Paquet, L.; Beaulieu, C.; Corriveau, A. Photodegradation of RDX in aqueous solution: A

  1. Passive Sampling in Regulatory Chemical Monitoring of Nonpolar Organic Compounds in the Aquatic Environment

    DEFF Research Database (Denmark)

    Booij, Kees; Robinson, Craig D; Burgess, Robert M

    2016-01-01

    and shortcomings of passive sampling are assessed for water, sediments, and biota. Passive water sampling is a suitable technique for measuring concentrations of freely dissolved compounds. This method yields results that are incompatible with the EU's quality standard definition in terms of total concentrations...... in water, but this definition has little scientific basis. Insufficient quality control is a present weakness of passive sampling in water. Laboratory performance studies and the development of standardized methods are needed to improve data quality and to encourage the use of passive sampling...

  2. Attomole detection of isotope-labeled compounds in chemical defense research

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, J.S.; Buchholz, B.A.; Pawley, N.H.; Mauthe, R.E.; Dingley, K.; Turteltaub, K.

    1996-11-01

    AMS detects 14C at zeptomole to femtomole sensitivities. We detected the effect of ChE-blocking pyridostigmine bromide on the CNS uptake of a pyrethroid insecticide at scaled human-equivalent exposures in rats. Significant blood to brain protection from permethrin dosed at 5mg/kg is seen in the CNS of rats receiving pyridostigmine bromide pretreatments in chow at 2mg/kg/day. The synergy of these compounds was suggested as a precursor to some symptoms of `Gulf War Syndrome`.

  3. Evaluation of some microbial agents, natural and chemical compounds for controlling tomato leaf miner, Tuta absoluta (Meyrick (Lepidoptera: Gelechiidae

    Directory of Open Access Journals (Sweden)

    Abd El-Ghany Nesreen M.

    2016-12-01

    Full Text Available Solanaceous plants have a great economic impact in Egypt. These groups of plants include potatoes, tomatoes and eggplants. The new invasive pest of tomatoes, Tuta absoluta (Meyrick causes the greatest crop losses which can range from 60 to 100%. After its detection in Egypt during the last half of 2009, it spread quickly to all provinces in the country. We aiming to propose a sustainable control program for this devastating pest. In this research we tested three groups of control agents. The first was microbial and natural, the second - plant extracts and the third - chemical insecticides. Our results showed that the impact of T. absoluta can be greatly reduced by the use of sustainable control measures represented by different insecticide groups. Bioassay experiments showed that this devastating pest can be controlled with some compounds that give high mortality rates. Of these compounds, spinosad and Beauveria bassiana, microbial control agents, followed by azadirachtin, gave the best results in controlling T. absoluta. Of the chemical insecticides, lambda-cyhalotrin was the most effective, followed by lufenuron and profenofos. In conclusion we encourage farmers to use microbial and natural control measures in combating the tomato leafminer, T. absoluta, in Integrated Pest Mangement (IPM programs.

  4. Chemical environment effects on the Kβ emission spectra in P compounds

    International Nuclear Information System (INIS)

    Ceppi, S.; Tirao, G.; Stutz, G.; Riveros, J.A.

    2008-01-01

    Several clusters of PO 4 3- and P 2 O 7 4- were studied in different chemical environment by measuring the Kβ 1,3 , Kβ x and Kβ' lines from P-Kβ emission spectrum. The Kβ spectrum structures were analyzed from its relation with its chemical environment. In this paper, the cation influence and the cation substitution with H on satellite Kβ' line parameters were also studied. It was found that this line allows the light ligand atom to be identified and also the number of H bonds with the PO 4 3- cluster be characterized. Besides cation influence on the P-Kβ spectrum, it can be shown that this influence is smaller than the ligand atom and cation-H substitution. Theoretical spectra were obtained by using the DV-Xα method in order to compare it with the experimental data and to interpret the Kβ line structure in terms of molecular orbital theory

  5. [Experience in the use of chemical compounds for the primary identification and differentiation of enteroviruses].

    Science.gov (United States)

    Amvros'eva, T V; Votiakov, V I; Andreeva, O T; Kazinets, O N; Bogush, Z F; Sharko, R M; Kvacheva, Z B

    2003-02-01

    Data on the usage of chemical inhibitors nifan and belvtazid, which possess a selective and antienteroviral effect, in the primary identification of enteroviruses and their differentiation into polio- and non-poliomyelytic ones isolated from human clinical materials or the environment by using the cell culture are presented in the article. The method is recommended for the practical use by the virology service in the diagnostics of enteroviral infections and in the identification of cytopathic agents isolated from the enviroment.

  6. Montmorillonite Functionalized with Pralidoxime as a Material for Chemical Protection against Organophosphorous Compounds

    Science.gov (United States)

    2011-03-25

    methoxide (g97%) and diisopropyl fluorophosphate (DFP, 99%) were received from Sigma- Aldrich Chemical Co. and polyisobutylene ( PIB , viscosity average...to dryness. The pH of the solution equilibrated with the montmorillonite was 8.6. Elastomeric films were made by casting 10 wt % solution of PIB in...of montmorillonite or functionalized montmorillonite particles was added to a 1.0 g of PIB /toluene solution. The resulting paste was vigorously

  7. Some chemical synthesis of {sup 14}C labelled compounds of pharmaceutical or biological interest

    Energy Technology Data Exchange (ETDEWEB)

    Pichat, I.; Baret, C.; Audinot, M.; Herbert, M.; Lambin, J. [Commissariat a l' Energie Atomique, Lab. du Fort de Chatillon, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1955-07-01

    The recent discovery of the tuberculostatic properties of the hydrazide of isonicotinic acid (so-called 'Isoniazide', 'Rimifon') has raised considerably its interest, as for metabolic studies which it is more interesting to have it labelled with {sup 14}C. We describe in this report the chemical synthesis of {sup 14}C carboxyl labelled isoniazide which were done in the pyridine ring to highlight his metabolic function on the Koch's bacillus. (M.B.)

  8. Some chemical synthesis of 14C labelled compounds of pharmaceutical or biological interest

    International Nuclear Information System (INIS)

    Pichat, I.; Baret, C.; Audinot, M.; Herbert, M.; Lambin, J.

    1955-01-01

    The recent discovery of the tuberculostatic properties of the hydrazide of isonicotinic acid (so-called 'Isoniazide', 'Rimifon') has raised considerably its interest, as for metabolic studies which it is more interesting to have it labelled with 14 C. We describe in this report the chemical synthesis of 14 C carboxyl labelled isoniazide which were done in the pyridine ring to highlight his metabolic function on the Koch's bacillus. (M.B.)

  9. STUDY REGARDING THE CORELATION BETWEEN SOMATIC CELLS COUNT AND MAJOR CHEMICAL COMPOUNDS IN RAW MILK

    Directory of Open Access Journals (Sweden)

    S. ACATINCĂI

    2008-10-01

    Full Text Available This study approaches the dynamic of somatic cells number and chemical composition of milk during 13 months of control. The study also investigates the correlations between the number of somatic cells and some chemical parameters in milk. Studies were carried out on Romanian Black and White cows between March 2005 and March 2006 at the Didactical farm of the Banat University of Agricultural Sciences Timisoara. As quality indicator, the number of somatic cells has different values among the controls. Average values for the 13 months of control, with the exception of three controls, were below maximum limit admitted from 1th of January 2007 (600000 SCC/ml milk. There weren’t any significant differences for SCC between the two seasons. Chemical parameters in milk varied in close limits and the differences were not significant, with one exception for fat percent. Fat percent is higher (p<0.05 in the cold season 3.87% compared with 3.55% during the warm season. Somatic cells number is weak correlated with lactose and strong correlated with proteins.

  10. Chemical compounds related to nutraceutical and industrial qualities of non-transgenic soybean genotypes.

    Science.gov (United States)

    Carrera, Constanza S; Dardanelli, Julio L; Soldini, Diego O

    2014-05-01

    Information about the chemical profile of soybean seed is valuable for breeding programs aimed at obtaining value-added products to meet the demands of niche markets. The objective of this study was to determine seed composition of non-transgenic soybean genotypes with specialty characters in different environments of Argentina. Protein and oil contents ranged from 396 to 424 g kg⁻¹ and from 210 to 226 g kg⁻¹, respectively. Oleic and linolenic acid ratio, the general indicator of oil quality, varied from 2.7 to 3.8. The oil contained high levels of total tocopherols (1429-1558 mg kg⁻¹) and the meal exhibited high levels of total isoflavones (2.91-4.62 mg g⁻¹). The biplot showed that oleic, linoleic and linolenic acids, γ-, δ- and total tocopherols, genistin, malonyl daidzin and genistin, acetyl daidzin and glycitin and total isoflavones allowed the greatest discrimination among the genotypes studied. Different chemical profiles of each non-transgenic genotype analyzed were established and, therefore, their identity was defined. These results are important for breeders who intend to obtain new genotypes with improved meal and oil quality, as well as for processors and exporters, who could use them directly as raw material for soyfood processing for nutraceutical purposes. © 2013 Society of Chemical Industry.

  11. Leaf surface lipophilic compounds as one of the factors of silver birch chemical defense against larvae of gypsy moth.

    Directory of Open Access Journals (Sweden)

    Vyacheslav V Martemyanov

    Full Text Available Plant chemical defense against herbivores is a complex process which involves a number of secondary compounds. It is known that the concentration of leaf surface lipophilic compounds (SLCs, particularly those of flavonoid aglycones are increased with the defoliation treatment of silver birch Betula pendula. In this study we investigated how the alteration of SLCs concentration in the food affects the fitness and innate immunity of the gypsy moth Lymantria dispar. We found that a low SLCs concentrations in consumed leaves led to a rapid larval development and increased females' pupae weight (= fecundity compared to larvae fed with leaves with high SLCs content. Inversely, increasing the compounds concentration in an artificial diet produced the reverse effects: decreases in both larval weight and larval survival. Low SLCs concentrations in tree leaves differently affected larval innate immunity parameters. For both sexes, total hemocytes count in the hemolymph increased, while the activity of plasma phenoloxidase decreased when larvae consume leaves with reduced content of SLCs. Our results clearly demonstrate that the concentration of SLCs in silver birch leaves affects not only gypsy moth fitness but also their innate immune status which might alter the potential resistance of insects against infections and/or parasitoids.

  12. Fruits from the Brazilian Cerrado region: Physico-chemical characterization, bioactive compounds, antioxidant activities, and sensory evaluation.

    Science.gov (United States)

    Schiassi, Maria Cecília Evangelista Vasconcelos; Souza, Vanessa Rios de; Lago, Amanda Maria Teixeira; Campos, Letícia Gabrielle; Queiroz, Fabiana

    2018-04-15

    Given the economic importance of fruit processing, this study aimed to analyze the chemical composition, antioxidant activity, and sensorial acceptance of six fruit pulps from the Brazilian Cerrado. For bioactive compounds of the selected fruits, buriti contains the highest carotenoid content (2.85 mg licopene/100 g e 4.65 mg β-carotene/100g), however showed the lowest ascorbic acid concentration (7.42 mg/100g); while mangaba contains the highest ascorbic acid concentration (175.06 mg/100g), but obtained the lowest total phenolic compounds (46.85 mg GAEs/100g) and antioxidant capacity. The marolo reported the highest total phenolic compounds (728.17 mg GAEs/100g), total fiber (21.62%), and a high antioxidant potential. Regarding the mineral composition, marolo stood out as potassium (378.69 mg/100g) and magnesium (31.78 mg/100g) contents, and yellow mombin as phosphorus (26.24 mg/100g) content. Finally, juice prepared using cagaita and marolo had greater sensorial acceptance. The composition of fruit pulps indicated the potential there for the development of new food products. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Microbial Succession and the Dynamics of Chemical Compounds during the Solid-State Fermentation of Pu-erh Tea

    Directory of Open Access Journals (Sweden)

    Yan Ma

    2017-02-01

    Full Text Available An in-depth knowledge of the microbiota and metabolites in the solid-state fermentation (SSF of Post-fermented Pu-erh tea (Pu-erh Shucha, PFPT, a Chinese traditional tea with various health benefits, is essential to develop modern fermentation technology. In this work, the microbial diversity and succession in two laboratory-developed SSF protocols for PFPT were investigated using pyrosequencing analyses of the bacterial 16S rRNA and fungal 18S rRNA genes. The active bacteria in the initial stages of SSF (seven days were from the raw materials and environment, with a dominance of Proteobacteria in both the raw materials and SSF after seven days. The environmental bacteria were inoculated into the tea mass throughout the fermentation process and multiplied, with a dominance of Firmicutes at day 14 and 21, and then Firmicutes and Actinobacteria at the last stages of fermentation (day 28 and 35. The dominant fungi came from the raw material and were identified at the genus level as Aspergillus throughout the SSF process. The contents of tea polyphenols, free amino acids, gallic acid, theaflavin, thearubigin, and catechins decreased significantly (p < 0.05, while the level of theabrownin increased significantly (p < 0.05. The caffeine content showed no significant change (p > 0.05. In total, 30 bacterial and three fungal genera showed significant correlations to 1–8 and 3–4 identified tea compounds, respectively (p < 0.05. The dynamics of the microbiota and chemical compounds, and correlations between their changes in the SSF of PFPT were revealed, and present a foundation for further studies on the microbial effects on chemical compounds.

  14. Optimization and application of atmospheric pressure chemical and photoionization hydrogen-deuterium exchange mass spectrometry for speciation of oxygen-containing compounds.

    Science.gov (United States)

    Acter, Thamina; Kim, Donghwi; Ahmed, Arif; Jin, Jang Mi; Yim, Un Hyuk; Shim, Won Joon; Kim, Young Hwan; Kim, Sunghwan

    2016-05-01

    This paper presents a detailed investigation of the feasibility of optimized positive and negative atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) and atmospheric pressure photoionization (APPI) MS coupled to hydrogen-deuterium exchange (HDX) for structural assignment of diverse oxygen-containing compounds. The important parameters for optimization of HDX MS were characterized. The optimized techniques employed in the positive and negative modes showed satisfactory HDX product ions for the model compounds when dichloromethane and toluene were employed as a co-solvent in APCI- and APPI-HDX, respectively. The evaluation of the mass spectra obtained from 38 oxygen-containing compounds demonstrated that the extent of the HDX of the ions was structure-dependent. The combination of information provided by different ionization techniques could be used for better speciation of oxygen-containing compounds. For example, (+) APPI-HDX is sensitive to compounds with alcohol, ketone, or aldehyde substituents, while (-) APPI-HDX is sensitive to compounds with carboxylic functional groups. In addition, the compounds with alcohol can be distinguished from other compounds by the presence of exchanged peaks. The combined information was applied to study chemical compositions of degraded oils. The HDX pattern, double bond equivalent (DBE) distribution, and previously reported oxidation products were combined to predict structures of the compounds produced from oxidation of oil. Overall, this study shows that APCI- and APPI-HDX MS are useful experimental techniques that can be applied for the structural analysis of oxygen-containing compounds.

  15. Relationships between Chemical Structure and Rat Repellency. 2. Compounds Screened Between 1950 and 1960

    Science.gov (United States)

    1974-08-01

    AND 1960. BY: Walter A. Bowles 1 James B. DeWitt 1* Vytautas A. Adomaitis 1 John J. Pratt, Jr. 2 1. Bureau of Sport Fisheries and Wildlife, US Dept...United States Department of the Interior Bureau of Sport Fisheries and Wildlife Patuxent Wildlife Research Center Laurel, Maryland V-C Chemical Company...98 GE BVMR D01 j 122 ’ 4454 43,107 GR DVMY4 4455 43,108 GR BG D- VMR 4456 43,107 GR CG DVMR BE 4457 43,108 GR BVMR DG 4458 43,108 GR CG DVMR BR 4459

  16. In-silico ADME Studies for New Drug Discovery: From Chemical Compounds to Chinese Herbal Medicines.

    Science.gov (United States)

    Yan, Guojun; Wang, Xiaobing; Chen, Zhou; Wu, Xianhui; Pan, Jinhuo; Huang, Yushen; Wan, Gang; Yang, Zhaogang

    2017-07-21

    Nowadays, in silico tools are widely used to provide the potential structure of the metabolites formed depending on the site of metabolism. These methods can also highlight the molecular moieties that help to direct the molecule into the cytochrome cavity so that the site of metabolism is in proximity to the catalytic center. In this minireview, we summarized three aspects of the in silico methods in the application of prediction of ADME (absorption, distribution, metabolism and excretion) properties of compounds: structure-based approaches for predicting molecular modeling of drug metabolizing enzymes; in silico metabolite prediction; and pharmacophore models for analysis substrate specificity. Moreover, we also extended the in silico studies in Chinese herbal medicines (CHM) research. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  17. A study on the development of high Tc superconducting materials

    International Nuclear Information System (INIS)

    Won, D. Y.; Hong, G. Y.; Lee, H. G.; Lee, H. J.; Kim, C. J.; Kwon, S. C.; Kim, K. B.; Kang, Y. H.; Chang, I. S.; Choi, M. J.

    1992-01-01

    The major work of this project aims to develop the frictionless superconducting bearing with a high speed. The high magnetization YBaCuO bulk superconductor was prepared by Quasi-melt process. The frictionless superconducting magnetic bearing standed a rotating bar with a speed of 75,000 rpm, which were operated by an electric controller. The low temperature chemical vapor deposition technique was developed. YBaCuO superconducting film showing a superconductivity above 77K was successfully prepared at 650 deg C. Effect of oxygen partial pressure, substrate, deposition temperature on the film properties were also investigated. (Author)

  18. Chemical compounds and antimicrobial activity of petitgrain (Citrus aurantium L. var. amara essential oil

    Directory of Open Access Journals (Sweden)

    Gniewosz Małgorzata

    2017-12-01

    Full Text Available Introduction: Due to its low cost and easy availability on the market, the petitgrain oil is commonly used in food, cosmetics, and aromatherapy. Objective: The examination of chemical composition and antibacterial activity of commercial petitgrain oil. Methods: Identification of chemical components of the petitgrain oil was performed by gas chromatography (GC. The minimum inhibitory concentrations (MIC and minimum bactericidal/fungicidal concentrations (MBC/MFC were determined using macrodilution method for the reference strains of bacteria and fungi. Results: Twenty components were identified. The petitgrain oil contained mostly oxygenated monoterpene hydrocarbons (98.01%, and the main components included linalyl acetate (48.06% and linalool (26.88%. The MIC/MBC of the petitgrain oil for bacteria was in the range of 0.63-5.0/1.25-5.0 mg/ml and for fungi in the range of 1.25-40/5.0-80 mg/ml. Conclusion: The petitgrain oil had higher antibacterial activity than antifungal activity. Bacillus subtilis among the tested bacteria and Aspergillus niger and Penicillium expansum among the fungi were found to be highly inhibited by the petitgrain oil.

  19. The radiolysis of aqueous ammonium cyanide - Compounds of interest to chemical evolution studies

    International Nuclear Information System (INIS)

    Draganic, Z.D.; Jovanovic, S.

    1980-01-01

    Oxygen-free aqueous solutions of NH4CN (0.1 M, pH 9) were exposed to gamma rays from a Co-60 source, the mixture of nonvolatile products was fractionated, and the fractions were analyzed. The procedures were chosen to make effective investigations of radiolytic products, and to minimize the contributions of chemical changes which are known to occur in aqueous solution in the absence of ionizing radiation. It has been found that the main constituents are: urea, 25.9% an oligomer, very likely oligoimine (18.4%) and several fractions (about 50%) which release amino acids on hydrolysis. These fractions differ considerably, as shown by amino acid assay, enzymatic digestion, IR spectra, and biuret reaction. All these tests were found to be positive for two fractions in two further fractions the enzymatic cleavage was absent, but other tests were positive. Negative enzymatic and biuret tests, and no bands characteristic of amide or peptide, were found for a fraction whose hydrolysate consisted of 55% glycine. Although most of the isolated materials were found to be composite, the results of the analyses were sufficient for getting a reliable over-all picture of the chemical action of the ionizing radiation. The role of free radicals in reactions leading to the formations of radiolytic products was considered

  20. The radiolysis of aqueous ammonium cyanide - Compounds of interest to chemical evolution studies

    Energy Technology Data Exchange (ETDEWEB)

    Draganic, Z.D. (Institute za Nuklearne Nauke, Belgrade, Yugoslavia); Jovanovic, S. (Beograd, Univerzitet, Belgrade, Yugoslavia)

    1980-07-01

    Oxygen-free aqueous solutions of NH4CN (0.1 M, pH 9) were exposed to gamma rays from a Co-60 source, the mixture of nonvolatile products was fractionated, and the fractions were analyzed. The procedures were chosen to make effective investigations of radiolytic products, and to minimize the contributions of chemical changes which are known to occur in aqueous solution in the absence of ionizing radiation. It has been found that the main constituents are: urea, 25.9% an oligomer, very likely oligoimine (18.4%) and several fractions (about 50%) which release amino acids on hydrolysis. These fractions differ considerably, as shown by amino acid assay, enzymatic digestion, IR spectra, and biuret reaction. All these tests were found to be positive for two fractions in two further fractions the enzymatic cleavage was absent, but other tests were positive. Negative enzymatic and biuret tests, and no bands characteristic of amide or peptide, were found for a fraction whose hydrolysate consisted of 55% glycine. Although most of the isolated materials were found to be composite, the results of the analyses were sufficient for getting a reliable over-all picture of the chemical action of the ionizing radiation. The role of free radicals in reactions leading to the formations of radiolytic products was considered.

  1. New Approach to Evaluate the Antennal Response of an Adult Predator Insect to Different Volatile Chemical Compounds by using Electroantennogram Technique

    Science.gov (United States)

    Shonouda, Mourad L.

    The antennal response of adult syrphid flies to selected plant volatile chemical compounds was investigated in the present study. The main chemical classes and their chemical compounds were aldehydes (nonanal and benzaldehyde), monoterpene-alcohols (linalool and alpha-terpineol), ketones (6-methyl-5-heptene-2-one and 2-undecanone), hydrocarbons (tetradecane) and benzoids (methyl salicylate). Electroantennogram (EAG) records showed that the syrphid antennae were strongly responded to linalool, 6-methyl-5-heptene-2-one and methyl salicylate even at low concentrations, in addition to the high dose concentration of nonanal comparably to the other chemical compounds. The antennae of old syrphid adults were more responsive and elicited higher levels of responses to all compounds rather than young syrphid adults. The antennal sensitivity may differ from one compound to another according to the sex. The difference in responses could be attributed to the sensitivity of olfactory receptors and/or the characterization of binding protein(s). The quality of biocontrol agent could be improved if the chemical interaction between beneficial natural enemies and the surrounding environment is intensively studied and we clearly understand the chemical ecology of each natural enemy.

  2. Superconductivity: Is there a problem in transuranics?

    International Nuclear Information System (INIS)

    Colineau, Eric; Griveau, Jean-Christophe; Eloirdi, Rachel; Hen, Amir; Caciuffo, Roberto

    2014-01-01

    Superconductivity was first reported in 1942 for uranium metal (¡-U) and in 1958 for U compounds: UCo, U6Mn, U6Fe, and U6Co, with critical temperatures Tc, of 1.7, 2.3, 3.9, and 2.3K, respectively. A new class of U superconductors emerged in the early 1980’s with the discovery of U heavy fermion superconductors : UBe13 (Tc = 0.85K), UPt3 (Tc = 0.53K), URu2Si2 (Tc = 1.5K) , UPd2Al3 (Tc = 1.9K) … Furthermore, in most of these systems, the superconducting phases coexist with antiferromagnetic (AF) correlations which have characteristic temperatures, usually the Néel temperature TN, that are typically one order of magnitude greater than the corresponding superconducting critical temperatures Tc. Superconductivity was even shown to co-exist with ferromagnetism in e.g. UGe2 (Tc ï» 0.8K, TC ï» 30K at p ï» 1.2GPa) and URhGe (Tc = 0.25K, TC = 9.5K). Heavy fermion superconductors still remain a major challenge for condensed matter physics. The existence of heavy fermion superconductivity and its coexistence or proximity with magnetic order suggests that the conventional mechanism of phonon-mediated superconductivity is inappropriate and that alternative mechanisms, like spin fluctuations, should be considered for Cooper pairing

  3. Controlling superconductivity by tunable quantum critical points.

    Science.gov (United States)

    Seo, S; Park, E; Bauer, E D; Ronning, F; Kim, J N; Shim, J-H; Thompson, J D; Park, Tuson

    2015-03-04

    The heavy fermion compound CeRhIn5 is a rare example where a quantum critical point, hidden by a dome of superconductivity, has been explicitly revealed and found to have a local nature. The lack of additional examples of local types of quantum critical points associated with superconductivity, however, has made it difficult to unravel the role of quantum fluctuations in forming Cooper pairs. Here, we show the precise control of superconductivity by tunable quantum critical points in CeRhIn5. Slight tin-substitution for indium in CeRhIn5 shifts its antiferromagnetic quantum critical point from 2.3 GPa to 1.3 GPa and induces a residual impurity scattering 300 times larger than that of pure CeRhIn5, which should be sufficient to preclude superconductivity. Nevertheless, superconductivity occurs at the quantum critical point of the tin-doped metal. These results underline that fluctuations from the antiferromagnetic quantum criticality promote unconventional superconductivity in CeRhIn5.

  4. Chemical shifts of K-X-ray absorption edges on copper in different compounds by X-ray absorption spectroscopy (XAS) with Synchrotron radiation

    Science.gov (United States)

    Joseph, D.; Basu, S.; Jha, S. N.; Bhattacharyya, D.

    2012-03-01

    Cu K X-ray absorption edges were measured in compounds such as CuO, Cu(CH3CO2)2, Cu(CO3)2, and CuSO4 where Cu is present in oxidation state of 2+, using the energy dispersive EXAFS beamline at INDUS-2 Synchrotron radiation source at RRCAT, Indore. Energy shifts of ˜4-7 eV were observed for Cu K X-ray absorption edge in the above compounds compared to its value in elemental copper. The difference in the Cu K edge energy shifts in the different compounds having same oxidation state of Cu shows the effect of different chemical environments surrounding the cation in the above compounds. The above chemical effect has been quantitatively described by determining the effective charges on Cu cations in the above compounds.

  5. Nano-fabricated superconducting radio-frequency composites, method for producing nano-fabricated superconducting rf composites

    Science.gov (United States)

    Norem, James H.; Pellin, Michael J.

    2013-06-11

    Superconducting rf is limited by a wide range of failure mechanisms inherent in the typical manufacture methods. This invention provides a method for fabricating superconducting rf structures comprising coating the structures with single atomic-layer thick films of alternating chemical composition. Also provided is a cavity defining the invented laminate structure.

  6. Production of Monomeric Aromatic Compounds from Oil Palm Empty Fruit Bunch Fiber Lignin by Chemical and Enzymatic Methods

    Directory of Open Access Journals (Sweden)

    Pei-Ling Tang

    2015-01-01

    Full Text Available In this study, oil palm empty fruit bunch (OPEFBF was pretreated with alkali, and lignin was extracted for further degradation into lower molecular weight phenolic compounds using enzymes and chemical means. Efficiency of monomeric aromatic compounds production from OPEFBF lignin via chemical (nitrobenzene versus oxygen and enzymatic [cutinase versus manganese peroxidase (MnP] approaches was investigated. The effects of sodium hydroxide concentration (2, 5, and 10% wt. and reaction time (30, 90, and 180 minutes on the yield of aromatic compounds were studied. The results obtained indicated that nitrobenzene oxidation produced the highest yield (333.17±49.44 ppm hydroxybenzoic acid, 5.67±0.25 ppm p-hydroxybenzaldehyde, 25.57±1.64 ppm vanillic acid, 168.68±23.23 ppm vanillin, 75.44±6.71 ppm syringic acid, 815.26±41.77 ppm syringaldehyde, 15.21±2.19 ppm p-coumaric acid, and 44.75±3.40 ppm ferulic acid, among the tested methods. High sodium hydroxide concentration (10% wt. was needed to promote efficient nitrobenzene oxidation. However, less severe oxidation condition was preferred to preserve the hydroxycinnamic acids (p-coumaric acid and ferulic acid. Cutinase-catalyzed hydrolysis was found to be more efficient than MnP-catalyzed oxidation in the production of aromatic compounds. By hydrolyzed 8% wt. of lignin with 0.625 mL cutinase g−1 lignin at pH 8 and 55°C for 24 hours, about 642.83±14.45 ppm hydroxybenzoic acid, 70.19±3.31 ppm syringaldehyde, 22.80±1.04 ppm vanillin, 27.06±1.20 ppm p-coumaric acid, and 50.19±2.23 ppm ferulic acid were produced.

  7. Comparison of different exhaustive and biomimetic extraction techniques for chemical and biological analysis of polycyclic aromatic compounds in river sediments

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Tobias [Free Univ. Berlin (Germany). Dept. of Earth Sciences, Hydrogeology; Seiler, Thomas B.; Hollert, Henner [RWTH Aachen Univ. (Germany). Dept. of Ecosystem Analysis; Streck, Georg [UFZ Helmholtz-Centre for Environmental Research, Leipzig (Germany). Dept. of Effect-Directed Analysis; Braunbeck, Thomas

    2012-10-15

    The importance of the bioaccessible fractions of particle-bound contaminants is a key feature for the assessment of their likely risks to the aquatic environment. The present study investigated the extractability and potential toxicity of polycyclic aromatic hydrocarbons (PAHs) in river sediments. This study combined chemical with bioanalytical tools to establish a more in-depth insight into the relationship between the extractability of sediment contaminants, the chemodynamic properties of each extraction approach, and resulting toxicity. Sediment samples were treated with different extraction methods, namely Soxhlet extraction with acetone (SOX), membrane dialysis extraction (MDE) with n-hexane, ultrasonic extraction with acetone (USE), and extraction with (2-hydroxpropyl)-{beta}-cyclodextrin (HBCD). The extracts were analyzed for PAHs using gas chromatography/mass spectrometry and tested using the neutral red retention assay and the ethoxyresorufin-O-deethylase (EROD) induction assay with the permanent fish cell line RTL-W1. The SOX and MDE approaches were comparable in their extraction power regarding PAHs and their cytotoxicity. However, the EROD activity differed between SOX and MDE, possibly due to retardation effects of the polyethylene membrane used in MDE. Thus, macromolecular components of the sediment were not extracted and therefore did not contribute to toxicity. HBCD extraction provided 3.4 % of the total PAH content in the sediments and might be an appropriate approach to predict the bioaccessible fraction. USE showed an extraction power between the HBCD approach and the MDE as well as SOX and MDE method. Hence, USE is neither appropriate for exhaustive extraction nor for biomimetic extraction. MDE and SOX have been approved for the exhaustive extraction of PAHs from sediments for a worst case assessment of effect potentials. The influence of the low-density polyethylene membrane and the experimental conditions on the diffusion of compounds with

  8. jCompoundMapper: An open source Java library and command-line tool for chemical fingerprints.

    Science.gov (United States)

    Hinselmann, Georg; Rosenbaum, Lars; Jahn, Andreas; Fechner, Nikolas; Zell, Andreas

    2011-01-10

    The decomposition of a chemical graph is a convenient approach to encode information of the corresponding organic compound. While several commercial toolkits exist to encode molecules as so-called fingerprints, only a few open source implementations are available. The aim of this work is to introduce a library for exactly defined molecular decompositions, with a strong focus on the application of these features in machine learning and data mining. It provides several options such as search depth, distance cut-offs, atom- and pharmacophore typing. Furthermore, it provides the functionality to combine, to compare, or to export the fingerprints into several formats. We provide a Java 1.6 library for the decomposition of chemical graphs based on the open source Chemistry Development Kit toolkit. We reimplemented popular fingerprinting algorithms such as depth-first search fingerprints, extended connectivity fingerprints, autocorrelation fingerprints (e.g. CATS2D), radial fingerprints (e.g. Molprint2D), geometrical Molprint, atom pairs, and pharmacophore fingerprints. We also implemented custom fingerprints such as the all-shortest path fingerprint that only includes the subset of shortest paths from the full set of paths of the depth-first search fingerprint. As an application of jCompoundMapper, we provide a command-line executable binary. We measured the conversion speed and number of features for each encoding and described the composition of the features in detail. The quality of the encodings was tested using the default parametrizations in combination with a support vector machine on the Sutherland QSAR data sets. Additionally, we benchmarked the fingerprint encodings on the large-scale Ames toxicity benchmark using a large-scale linear support vector machine. The results were promising and could often compete with literature results. On the large Ames benchmark, for example, we obtained an AUC ROC performance of 0.87 with a reimplementation of the extended

  9. Superconductivity Bordering Rashba Type Topological Transition

    Energy Technology Data Exchange (ETDEWEB)

    Jin, M. L.; Sun, F.; Xing, L. Y.; Zhang, S. J.; Feng, S. M.; Kong, P. P.; Li, W. M.; Wang, X. C.; Zhu, J. L.; Long, Y. W.; Bai, H. Y.; Gu, C. Z.; Yu, R. C.; Yang, W. G.; Shen, G. Y.; Zhao, Y. S.; Mao, H. K.; Jin, C. Q.

    2017-01-04

    Strong spin orbital interaction (SOI) can induce unique quantum phenomena such as topological insulators, the Rashba effect, or p-wave superconductivity. Combining these three quantum phenomena into a single compound has important scientific implications. Here we report experimental observations of consecutive quantum phase transitions from a Rashba type topological trivial phase to topological insulator state then further proceeding to superconductivity in a SOI compound BiTeI tuned via pressures. The electrical resistivity measurement with V shape change signals the transition from a Rashba type topological trivial to a topological insulator phase at 2 GPa, which is caused by an energy gap close then reopen with band inverse. Superconducting transition appears at 8 GPa with a critical temperature TC of 5.3 K. Structure refinements indicate that the consecutive phase transitions are correlated to the changes in the Bi–Te bond and bond angle as function of pressures. The Hall Effect measurements reveal an intimate relationship between superconductivity and the unusual change in carrier density that points to possible unconventional superconductivity.

  10. Chemical oxidation of a malodorous compound, indole, using iron entrapped in calcium alginate beads.

    Science.gov (United States)

    Ben Hammouda, Samia; Adhoum, Nafaâ; Monser, Lotfi

    2016-01-15

    Iron-alginate beads (Fe-ABs) were successfully prepared by the ion-gelation method, and applied as heterogeneous Fenton catalysts for the removal of a malodorous compound 'indole'. Similarly, copper-enriched alginate beads (Cu-ABs) were synthesized and tested as like-Fenton catalyst, however, their application proved not to be effective for this purpose. Fe-ABs catalysts were characterized by FTIR, SEM, EDS and AAS spectroscopy. Results pointed out that the parameters affecting Fenton catalysis must be carefully chosen to avoid excessive iron release. Under optimal conditions, complete indole removal and considerably high reduction of TOC, without significant leaching was achieved. Indole decay followed a pseudo-first-order kinetics. The absolute rate constant for indole hydroxylation was 3.59×10(9) M(-1) s(-1), as determined by the competition kinetics method. Four reaction intermediates (Isatin, Dioxindole, Oxindole and Anthralinic acid) were identified by ULC/MS/MS analysis. Short-chain aliphatic carboxylic acids like formic, acetic, oxalic, maleic, oxamic and pyruvic acids were identified by ion exclusion chromatography and as end-products. Based on the identified by-products, a plausible mineralization pathway was proposed. Moreover, the catalyst was recovered quantitatively by simple filtration and reused for several times without significant loss of activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. 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.

  12. The relationship between mutagenicity and chemical composition of polycyclic aromatic compounds from coal pyrolysis.

    Science.gov (United States)

    Wornat, M J; Braun, A G; Hawiger, A; Longwell, J P; Sarofim, A F

    1990-01-01

    The polycyclic aromatic compounds (PAC) produced from the pyrolysis of a bituminous coal at temperatures of 1125 to 1425 degrees K prove to be mutagenic to S. typhimurium, both in the presence and in the absence of postmitochondrial supernatant (PMS) prepared from Aroclor 1254-induced rat liver. Mutagenicity of the PAC samples measured in the absence of PMS exhibits little dependence on pyrolysis temperature; that measured in its presence is higher at the higher pyrolysis temperatures. However, because of the decrease in PAC yield as the temperature is raised, mutagenicity per mass of coal consumed falls with an increase in temperature if measured without PMS (-PMS) and peaks at an intermediate temperature of 1378 degrees K if measured with PMS (+PMS). Using a new chromatographic technique, we have split each coal-derived PAC sample into two fractions: LC1, containing PAC with alkyl and O-containing substitutions and LC2, consisting of unsubstituted PAC. Substituted (LC1) fractions show no significant +PMS mutagenicity, indicating that, as a whole, the alkylated PAC in our coal pyrolysis products are not mutagenic. Only at the higher temperatures do the substituted fractions exhibit significant -PMS mutagenicity, attributed to PAC with carbonyl or etheric functionalities. The extremely low yields of the substituted PAC under the conditions where they show some activity, however, ensure that they contribute little to overall mutagenicity. In contrast to the substituted fractions, the unsubstituted (LC2) fractions display significant mutagenicity under all conditions and appear to be responsible for virtually all of the mutagenicity in these coal-derived PAC samples. In this fraction, -PMS activity is attributed to nitrogen-containing heterocyclic aromatics. PMID:2190813

  13. Laser activated superconducting switch

    International Nuclear Information System (INIS)

    Wolf, A.A.

    1976-01-01

    A superconducting switch or bistable device is described consisting of a superconductor in a cryogen maintaining a temperature just below the transition temperature, having a window of the proper optical frequency band for passing a laser beam which may impinge on the superconductor when desired. The frequency of the laser is equal to or greater than the optical absorption frequency of the superconducting material and is consistent with the ratio of the gap energy of the switch material to Planck's constant, to cause depairing of electrons, and thereby normalize the superconductor. Some embodiments comprise first and second superconducting metals. Other embodiments feature the two superconducting metals separated by a thin film insulator through which the superconducting electrons tunnel during superconductivity

  14. The environmental behavior and chemical fate of energetic compounds (TNT, RDX, tetryl) in soil and plant systems

    International Nuclear Information System (INIS)

    Cataldo, D.A.; Harvey, S.D.; Fellows, R.J.

    1993-06-01

    Munitions materials can accumulate or cycle in terrestrial environs at production and manufacturing facilities and thus pose potential heath and environmental concerns. To address questions related to food chain accumulation, the environmental behavior of energetic compounds (2,4,6-trinitrotoluene,TNT; hexahydro-1,3,5-trinitro-1,3,5-triazine, RDX; 2,4,6-trinitrophenylmethylnitramine, tetryl) was evaluated. Emphasis was placed on determining the potential for soil/plant transfer of munitions residues, translocation and distribution within the plant, the extent to which compounds were metabolized following accumulation, and the chemical nature and form of accumulated residues. Both TNT and tetryl undergo extensive chemical transformation in soil, forming aminodinitrotoluene isomers and N-methyl-2,4,6-trinitroaniline residues, respectively, along with a series of unknowns. After 60 days, only 30% of the amended TNT and 8% of the amended tetryl remained unchanged in the soil. In contrast, 78% of the soil-amended RDX remained unchanged after 60 days. After 60 days, plants grown in soils containing 10 ppm residues contained from 5 μg TNT/g to 600 μg RDX/G fresh wt. tissue. TNT and tetryl residues were primarily accumulated in roots (75%), while RDX was concentrated in leaves and seed. The principal transport form for TNT (root to shoot) was an acid labile conjugate of aminodinitrotoluene; RDX was transported unchanged. On accumulation in roots and leaves, highly polar and non-extractable TNT metabolites dominated, with the aminodinitrotoluene isomers accounting for less than 20% of the residues present. Only a few percent were present as the parent TNT. RDX was partitioned similarly to TNT, with 8 to 30% of the RDX appearing as polar metabolites, 20--50% as parent RDX, and the balance as non-extractable residues. Tetryl was metabolized to N-methyl-2,4,6-trinitroaniline and a variety of polar metabolites

  15. Screening and evaluation of active compounds in polyphenol mixtures by HPLC coupled with chemical methodology and its application.

    Science.gov (United States)

    Zhao, Yue; Wang, Ying; Jiang, Zi-Tao; Li, Rong

    2017-07-15

    An off-line high performance liquid chromatography (HPLC) coupled with chemical methods has been developed to evaluate antioxidant activity of 11 standard polyphenol compounds (SPCs) and vitamin C (Vc) in terms of radical scavenging abilities. The structure-activity relationships of each SPC were also discussed. SPCs showed different abilities in scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-3-ethyl-benzthiazoline-6-sulphonate (ABTS + ) and hydroxyl (OH) free radicals. Among SPCs, quercetin and kaempferol, as typical flavonoids, displayed the greatest radical-scavenging activities and even exhibited higher activity in OH radical removal ability than that of Vc. Furthermore, the proposed method was also applied to screening polyphenolic antioxidant components from Cichorium endivia L. (C. endivia) seed extract. The results indicated that cynarin in the extract was a more active compound to scavenge DPPH and ABTS + radicals than chlorogenic acid, while chlorogenic acid had stronger capacity in scavenging OH free radicals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Assessing the distribution of volatile organic compounds using land use regression in Sarnia, "Chemical Valley", Ontario, Canada

    Directory of Open Access Journals (Sweden)

    Luginaah Isaac N

    2009-04-01

    Full Text Available Abstract Background Land use regression (LUR modelling is proposed as a promising approach to meet some of the challenges of assessing the intra-urban spatial variability of ambient air pollutants in urban and industrial settings. However, most of the LUR models to date have focused on nitrogen oxides and particulate matter. This study aimed at developing LUR models to predict BTEX (benzene, toluene, ethylbenzene, m/p-xylene and o-xylene concentrations in Sarnia, 'Chemical Valley', Ontario, and model the intra-urban variability of BTEX compounds in the city for a community health study. Method Using Organic Vapour Monitors, pollutants were monitored at 39 locations across the city of Sarnia for 2 weeks in October 2005. LUR models were developed to generate predictor variables that best estimate BTEX concentrations. Results Industrial area, dwelling counts, and highways adequately explained most of the variability of BTEX concentrations (R2: 0.78 – 0.81. Correlations between measured BTEX compounds were high (> 0.75. Although most of the predictor variables (e.g. land use were similar in all the models, their individual contributions to the models were different. Conclusion Yielding potentially different health effects than nitrogen oxides and particulate matter, modelling other air pollutants is essential for a better understanding of the link between air pollution and health. The LUR models developed in these analyses will be used for estimating outdoor exposure to BTEX for a larger community health study aimed at examining the determinants of health in Sarnia.

  17. Physico-Chemical Characterization, Bioactive Compounds and Antioxidant Activity of Malay Apple [Syzygium malaccense (L. Merr. & L.M. Perry].

    Directory of Open Access Journals (Sweden)

    Polyana Campos Nunes

    Full Text Available The purpose of this study was to evaluate the physico-chemical characteristics, bioactive compounds and antioxidant activity of Malay apple fruit (Syzygium malaccense grown in Brazil with regard to the geographical origin and its peel fractions and edible portion analyzed independently. Fruit diameter, weight, yield, and centesimal composition, ascorbic acid, reductive sugars, total soluble solids, pH and fiber content were determined. Total phenolics (1293 mg gallic acid equivalent/100 g and total anthocyanins (1045 mg/100 g contents were higher in the peel, with the major anthocyanin identified using HPLC-DAD-MS/MS as cyanidin 3-glucoside. Higher values for DPPH antiradical scavenging activity (47.52 μMol trolox equivalent antioxidant capacity/g and Ferric Reducing Antioxidant Potential (FRAP, 0.19 mM ferreous sulfate/g were also observed in the peel fraction. All extracts tested showed the ability to inhibit oxidation in the β-carotene/linoleic acid system. This study highlights the potential of Malay apple fruit as a good source of antioxidant compounds with potential benefits to human health.

  18. Physico-Chemical Characterization, Bioactive Compounds and Antioxidant Activity of Malay Apple [Syzygium malaccense (L.) Merr. & L.M. Perry].

    Science.gov (United States)

    Nunes, Polyana Campos; Aquino, Jailane de Souza; Rockenbach, Ismael Ivan; Stamford, Tânia Lúcia Montenegro

    2016-01-01

    The purpose of this study was to evaluate the physico-chemical characteristics, bioactive compounds and antioxidant activity of Malay apple fruit (Syzygium malaccense) grown in Brazil with regard to the geographical origin and its peel fractions and edible portion analyzed independently. Fruit diameter, weight, yield, and centesimal composition, ascorbic acid, reductive sugars, total soluble solids, pH and fiber content were determined. Total phenolics (1293 mg gallic acid equivalent/100 g) and total anthocyanins (1045 mg/100 g) contents were higher in the peel, with the major anthocyanin identified using HPLC-DAD-MS/MS as cyanidin 3-glucoside. Higher values for DPPH antiradical scavenging activity (47.52 μMol trolox equivalent antioxidant capacity/g) and Ferric Reducing Antioxidant Potential (FRAP, 0.19 mM ferreous sulfate/g) were also observed in the peel fraction. All extracts tested showed the ability to inhibit oxidation in the β-carotene/linoleic acid system. This study highlights the potential of Malay apple fruit as a good source of antioxidant compounds with potential benefits to human health.

  19. Effect of DPA and 1-MCP on chemical compounds related to superficial scald of Granny Smith apples

    Energy Technology Data Exchange (ETDEWEB)

    Moggia, C.; Moya-Leon, M. A.; Pereira, M.; Yuri, J. A.; Lobos, G. A.

    2010-07-01

    Research was carried out to study the mode of action of diphenylamine (DPA) and 1-methylcyclopropene (1-MCP), on control of superficial scald of Granny Smith apples (Malus domestica Borkh.), and its relation with chemical compounds. Fruit was harvested from a commercial orchard in Chile, 182 and 189 days after full bloom and received the following treatments: DPA (2,000 ppm); 1-MCP (1.2 ppm) and control (no treatment). All fruit was stored for 4 or 6 months at 0 degree centigrade. A completely randomized factorial design was used (2 harvest dates by 3 post harvest treatments). Monthly measurements were made on maturity indices, ethylene production rate (EPR), scald related compounds [a-farnesene (AF), conjugated trienes (CT), total anti-oxidants (AO)], and cell membrane stability. Following 4 and 6 months of storage, plus 7 days at 20 degree centigrade, scald was evaluated. After 6 months, DPA-treated fruit, from both harvests, showed similar firmness, EPR and AO, compared to the control. However, AF and CT were lower, and cell membrane stability higher. Conversely, 1-MCP-treated fruit showed a noticeable EPR suppression and AF inhibition, along with higher firmness, lower CT and AO, compared to the control and DPA. Furthermore, cell membrane stability was superior to that of the control and similar to that of the DPA. Treated fruit (DPA and 1-MCP) showed an important reduction in scald compared to the control. The effect of 1-MCP on the investigated compounds and the reduction in scald, confirms that ethylene plays a major role on its development. (Author) 50 refs.

  20. Frontiers in Superconducting Materials

    CERN Document Server

    Narlikar, Anant V

    2005-01-01

    Frontiers in Superconducting Materials gives a state-of-the-art report of the most important topics of the current research in superconductive materials and related phenomena. It comprises 30 chapters written by renowned international experts in the field. It is of central interest to researchers and specialists in Physics and Materials Science, both in academic and industrial research, as well as advanced students. It also addresses electronic and electrical engineers. Even non-specialists interested in superconductivity might find some useful answers.

  1. Superconductivity and their applications

    OpenAIRE

    Roque, António

    2017-01-01

    Trabalho apresentado em International Conference on Renewable Energies and Power Quality (ICREPQ’17), 4 a 6 de Abril de 2017, Málaga, Espanha The research in the field of superconductivity has led to the synthesis of superconducting materials with features that allow you to expand the applicability of this kind of materials. Among the superconducting materials characteristics, the critical temperature of the superconductor is framing the range and type of industrial applications that can b...

  2. Surface and Superconductivity

    Science.gov (United States)

    Gor'kov, L. P.

    2006-07-01

    Experiments reveal the existence of metallic bands at surfaces of metals and insulators. The bands can be doped externally. We review properties of surface superconductivity that may set up in such bands at low temperatures and various means of superconductivity defection. The fundamental difference as compared to the ordinary superconductivity in metals, besides its two-dimensionality lies in the absence of the center of space inversion. This results in mixing between the singlet and triplet channels of the Cooper pairing.

  3. High-Temperature Superconductivity

    Science.gov (United States)

    Tanaka, Shoji

    2006-12-01

    A general review on high-temperature superconductivity was made. After prehistoric view and the process of discovery were stated, the special features of high-temperature superconductors were explained from the materials side and the physical properties side. The present status on applications of high-temperature superconductors were explained on superconducting tapes, electric power cables, magnets for maglev trains, electric motors, superconducting quantum interference device (SQUID) and single flux quantum (SFQ) devices and circuits.

  4. EFFECT OF GENOTYPE, SEX AND KEEPING TECHNOLOGY ON THE CHEMICAL COMPOUNDS OF BREAST AND THIGH MEAT

    Directory of Open Access Journals (Sweden)

    SZ. KONRÁD

    2009-10-01

    Full Text Available In the recent decades because of the alternative poultry meat production technologies (free range and organic farming, which are gaining ground in some of the European countries, only special slow growing breeds and hybrids can be used. The end products created by crossing the indigenous Yellow Hungarian hen with different meat type cocks were suitable for alternative keeping technology. The valuable meat parts of the pure bred Yellow Hungarian kept in free range for 84 days and the end product created with crossing (first group as well as the valuable meat parts of Ross 308 broilers fattened for 42 days in intensive keeping technology (second group were thoroughly examined in order to establish whether the genotype, sex and/or keeping technology has any kind of influence on different chemical parameters of the meat. There were no essential differences between the dry matter content of breast meat of the two different keeping technology groups (25.34 and 26.25%. However, dry matter content of thigh was 5.28 to 7.48 percentage points higher in the second group. Protein contents of breast and thigh meat were not affected by the keeping technology. Fat content of thigh meat was two and a half times higher than in the first group (6.03 and 13.73%. Thus, this study have revealed that only the ash content of breast meat affected from the keeping technology, as this parameter was higher in the first group than the second group (0.84 to 1.05 % vs 0.53 %.

  5. Chemical speciation of inorganic compounds under hydrothermal conditions. 1998 annual progress report

    International Nuclear Information System (INIS)

    Darab, J.G.; Fulton, J.L.; Steidler, G.T.; Stern, E.A.

    1998-01-01

    'To obtain the chemistry of metallic solute ions under aqueous and hydrothermal conditions in order to obtain key insights pertinent to the removal of toxic wastes. Elements present in Hanford tank wastes will be investigated to get a better understanding of how the high temperatures involved in vitrification will affect the hydrolysis-polymerization reaction. In the following summary of the x-ray absorption fine structure (XAFS) measurements under aqueous and hydrothermal conditions, most measurements below the critical temperature (375 C) were taken at about 200 bar pressure, while at supercritical temperatures the pressure was about 600 bar. Chemistry of Na 2 WO 4 Under Aqueous and Hydrothermal Conditions Tungsten, molybdenum, vanadium and, to a lesser agree, chromium, niobium and tantalum form isopolymetallates, polymeric species of rather complicated structure and complex chemical equilibria, in aqueous solution upon acidification. Except Tantalum, all of these elements are present in the Hanford tank wastes and it is not well understood how the high temperatures involved in vitrification will affect the hydrolysis-polymerization reaction. In March 1998, the authors launched a series of XAFS experiments to resolve these questions. Measurements were obtained for 0.2 molal tungstate solutions as a function of temperature (to 200 C) and as a function of starting pH. The outcome of these measurements is providing key insights into this chemistry as follows: (1) A change from tetrahedral to octahedral coordination of the oxygen atoms around the tungsten center atom can be detected upon increasing extent of polymerization. (2) At least one new feature shows up in the Fourier Transform of the k-weighted Chi plot (closely related to a radial distribution function) which is unambiguously attributed to a tungsten-tungsten scattering path, only present in the polymeric species. (3) Perhaps most interestingly, the XAFS data indicate a higher extent of polymerization at

  6. Estimate the Chemical Formula of Organic Compounds from Mass Spectrometry Data

    International Nuclear Information System (INIS)

    Tigor Nauli

    2002-01-01

    Mass spectrometer is one of the analysis methods that can determine molecular weight of a substance precisely. Molecular ionic mass measured by the spectrometer represents sum of its isotopes weight with high abundance. It is not equal to the atomic weights from average total of natural isotope of elements. Therefore, a single mass measurement suffices to decide the formula of a substance. Formula determination using mass data by trial and error is a cumbersome work. An algorithm developed by Lederberg can be used to predict molecular formulas from an integer molecular weight. It will search for all linear combination of mass after the molecular weight divided by one of its isotopes weight. Selection of the right molecular formula from a list of possible formulas can be assisted by the relative abundance of its isotopes. The heavy isotopes will appear in the spectrum as small peaks at one or more unit m/z next to the parent peak. The heights of smaller peak (P M+1 , P M+2 , ... ) compared with the height of parent peak (P M ) depend on the atom and its relative heavy isotopes. Hence, the relative peak heights could designate molecular formula of the substance. A computer application will help in producing a list of all possible molecular formulas from inputs of molecular ion peak results from mass spectrometry. The program calculates relative peak heights implementing Beynon rule. The output becomes a tool for choosing the actual formula of the substance. Although the formula algorithm could be implemented in all chemical groups, the computer program is purely made for an organic substance consists of carbon, hydrogen, oxygen and nitrogen. The computer outputs will inform the odd or even of ionic pairs and the number of bond and rings in the substance also. (author)

  7. Superconductivity and its application

    International Nuclear Information System (INIS)

    Spadoni, M.

    1988-01-01

    This paper, after a short introduction to superconductivity and to multifilamentary superconducting composites is aiming to review the state of the art and the future perspective of some of the applications of the superconducting materials. The main interest is focussed to large scale applications like, for istance, magnets for accelerators or fusion reactors, superconducting system for NMR thomography, etc. A short paragraph is dedicated to applications for high sensitivity instrumentation. The paper is then concluded by some considerations about the potentialities of the newly discovered high critical temperature materials

  8. Superconductivity in power engineering

    International Nuclear Information System (INIS)

    1989-01-01

    This proceedings volume presents 24 conference papers and 15 posters dealing with the following aspects: 1) Principles and elementary aspects of high-temperature superconductivity (3 plenary lectures); 2) Preparation, properties and materials requirements of metallic or oxide superconductors (critical current behaviour, soldered joints, structural studies); 3) Magnet technology (large magnets for thermonuclear fusion devices; magnets for particle accelerators and medical devices); 4) Magnetic levitation and superconductivity; 5) Cryogenics; 6) Energy storage systems using superconducting coils (SMES); 7) Superconducting power transmission cables, switches, transformers, and generator systems for power plant; 8) Supporting activities, industrial aspects, patents. There are thirty-eight records in the ENERGY database relating to individual conference papers. (MM) [de

  9. Superconducting linear accelerator cryostat

    International Nuclear Information System (INIS)

    Ben-Zvi, I.; Elkonin, B.V.; Sokolowski, J.S.

    1984-01-01

    A large vertical cryostat for a superconducting linear accelerator using quarter wave resonators has been developed. The essential technical details, operational experience and performance are described. (author)

  10. Magnetic and Superconducting Materials at High Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Struzhkin, Viktor V. [Carnegie Inst. of Washington, Washington, DC (United States)

    2015-03-24

    The work concentrates on few important tasks in enabling techniques for search of superconducting compressed hydrogen compounds and pure hydrogen, investigation of mechanisms of high-Tc superconductivity, and exploring new superconducting materials. Along that route we performed several challenging tasks, including discovery of new forms of polyhydrides of alkali metal Na at very high pressures. These experiments help us to establish the experimental environment that will provide important information on the high-pressure properties of hydrogen-rich compounds. Our recent progress in RIXS measurements opens a whole field of strongly correlated 3d materials. We have developed a systematic approach to measure major electronic parameters, like Hubbard energy U, and charge transfer energy Δ, as function of pressure. This technique will enable also RIXS studies of magnetic excitations in iridates and other 5d materials at the L edge, which attract a lot of interest recently. We have developed new magnetic sensing technique based on optically detected magnetic resonance from NV centers in diamond. The technique can be applied to study superconductivity in high-TC materials, to search for magnetic transitions in strongly correlated and itinerant magnetic materials under pressure. Summary of Project Activities; development of high-pressure experimentation platform for exploration of new potential superconductors, metal polyhydrides (including newly discovered alkali metal polyhydrides), and already known superconductors at the limit of static high-pressure techniques; investigation of special classes of superconducting compounds (high-Tc superconductors, new superconducting materials), that may provide new fundamental knowledge and may prove important for application as high-temperature/high-critical parameter superconductors; investigation of the pressure dependence of superconductivity and magnetic/phase transformations in 3d transition metal compounds, including

  11. Distribution of volatile organic compounds (VOCs) in surface water, soil, and groundwater within a chemical industry park in Eastern China.

    Science.gov (United States)

    Liu, Benhua; Chen, Liang; Huang, Linxian; Wang, Yongseng; Li, Yuehua

    2015-01-01

    This paper focuses on the distribution of volatile organic compounds (VOCs) in the surface water, soil, and groundwater within a chemical industry park in Eastern China. At least one VOC was detected in each of the 20 sampling sites, and the maximum number of VOCs detected in the surface water, groundwater, and soil were 13, 16, and 14, respectively. Two of the 10 VOCs with elevated concentrations detected in surface water, groundwater, and soil were chloroform and 1,2-dichloroethane. The characteristics of VOCs, which include volatility, boiling point, and solubility, could significantly affect their distribution in surface water, soil, and groundwater. However, due to the direct discharging of chemical industry wastewater into surface water, higher concentrations of VOCs (except chloroform) were detected in surface water than in soil and groundwater. Fortunately, the higher volatility of VOCs prevents the VOCs from impacting groundwater, which helps to maintain a lower concentration of VOCs in the groundwater than in both surface water and soil. This is because pollutants with relatively higher boiling points and lower solubilities have higher detection frequencies in soil, and contaminants with relatively lower boiling points and higher solubilities have higher detection frequencies in water, notably in surface water.

  12. In Silico and In Vitro Anticancer Activity of Isolated Novel Marker Compound from Chemically Modified Bioactive Fraction from Curcuma longa (NCCL).

    Science.gov (United States)

    Naqvi, Arshi; Malasoni, Richa; Gupta, Swati; Srivastava, Akansha; Pandey, Rishi R; Dwivedi, Anil Kumar

    2017-10-01

    Turmeric ( Curcuma longa ) is reported to possess wide array of biological activities. Herbal Medicament (HM) is a standardized hexane-soluble fraction of C. longa and is well known for its neuroprotective effect. In this study, we attempted to synthesize a novel chemically modified bioactive fraction from HM (NCCL) along with isolation and characterization of a novel marker compound (I). NCCL was prepared from HM. The chemical structure of the marker compound isolated from NCCL was determined from 1D/2D nuclear magnetic resonance, mass spectroscopy, and Fourier transform infrared. The compound so isolated was subjected to in silico and in vitro screenings to test its inhibitory effect on estrogen receptors. Molecular docking studies revealed that the binding poses of the compound I was energetically favorable. Among NCCL and compound I taken for in vitro studies, NCCL had exhibited good anti-cancer activity over compound I against MCF-7, MDA-MB-231, DU-145, and PC-3 cells. This is the first study about the synthesis of a chemically modified bioactive fraction which used a standardized extract since the preparation of the HM. It may be concluded that NCCL fraction having residual components induce more cell death than compound I alone. Thus, NCCL may be used as a potent therapeutic drug. In the present paper, a standardized hexane soluble fraction of Curcuma longa (HM) was chemically modified to give a novel bioactive fraction (NCCL). A novel marker compound was isolated from NCCL and was characerized using various spectral techniques. The compound so isolated was investigated for in-silico screenings. NCCL and isolated compound was subjected to in-vitro anti-cancer screenings against MCF 7, MDA MB 231 (breast adenocarcinoma) and DU 145 and PC 3 cell lines (androgen independent human prostate cancer cells). The virtual screenings reveals that isolated compound has shown favourable drug like properties. NCCL fraction having residual components induces more cell

  13. National inventory of alkylphenol ethoxylate compounds in U.S. sewage sludges and chemical fate in outdoor soil mesocosms

    International Nuclear Information System (INIS)

    Venkatesan, Arjun K.; Halden, Rolf U.

    2013-01-01

    We determined the first nationwide inventories of alkylphenol surfactants in U.S. sewage sludges (SS) using samples from the U.S. Environmental Protection Agency's 2001 national SS survey. Additionally, analysis of archived 3-year outdoor mesocosm samples served to determine chemical fates in SS-amended soil. Nonylphenol (NP) was the most abundant analyte (534 ± 192 mg/kg) in SS composites, followed by its mono- and di-ethoxylates (62.1 ± 28 and 59.5 ± 52 mg/kg, respectively). The mean annual load of NP and its ethoxylates in SS was estimated at 2408–7149 metric tonnes, of which 1204–4289 is applied on U.S. land. NP compounds showed observable loss from SS/soil mixtures (1:2), with mean half-lives ranging from 301 to 495 days. Surfactant levels in U.S. SS ten-times in excess of European regulations, substantial releases to U.S. soils, and prolonged half-lives found under field conditions, all argue for the U.S. to follow Europe's move from 20 years ago to regulate these chemicals. -- Highlights: ► First national survey of alkylphenol surfactants in U.S. sewage sludges. ► Nonylphenol (NP) and its ethoxylates were consistently detected in all samples. ► Levels of NP in U.S. biosolids exceed regulatory limit set by European Union. ► Significant surfactant releases to U.S. soils via biosolids land application. ► Half-lives >300 days for NP and its ethoxylates observed in outdoor soil mesocosms. -- First study providing national inventories of alkylphenol surfactants in U.S. sewage sludges (SS), shows significant release of chemicals to U.S. soils through SS land application

  14. Identification of volatile and semivolatile compounds in chemical ionization GC-MS using a mass-to-structure (MTS) Search Engine with integral isotope pattern ranking.

    Science.gov (United States)

    Liao, Wenta; Draper, William M

    2013-02-21

    The mass-to-structure or MTS Search Engine is an Access 2010 database containing theoretical molecular mass information for 19,438 compounds assembled from common sources such as the Merck Index, pesticide and pharmaceutical compilations, and chemical catalogues. This database, which contains no experimental mass spectral data, was developed as an aid to identification of compounds in atmospheric pressure ionization (API)-LC-MS. This paper describes a powerful upgrade to this database, a fully integrated utility for filtering or ranking candidates based on isotope ratios and patterns. The new MTS Search Engine is applied here to the identification of volatile and semivolatile compounds including pesticides, nitrosoamines and other pollutants. Methane and isobutane chemical ionization (CI) GC-MS spectra were obtained from unit mass resolution mass spectrometers to determine MH(+) masses and isotope ratios. Isotopes were measured accurately with errors of Search Engine and details performance testing with over 50 model compounds.

  15. Superconducting wire turns to electrical power

    CERN Document Server

    Sargent, P

    2003-01-01

    Two years after the discovery that magnesium diboride is a superconductor, engineers and entrepreneurs are keen to transform its properties into profit. The discovery of superconductivity at 39 K in the metallic compound magnesium diboride two years ago created quite a stir. Since then, physicists and chemists have come a long way in understanding the curious set of circumstances that lead to such a high critical temperature in this widely available material. At the same time, metallurgists, engineers and entrepreneurs have been focusing on the commercial potential of magnesium diboride as superconducting wire, which was the subject of a one-day meeting in Cambridge, UK, in April. Superconducting wire made from magnesium diboride could make 'second- generation' electrical machines commercially viable. (U.K.)

  16. Superconducting elliptical cavities

    CERN Document Server

    Sekutowicz, J K

    2011-01-01

    We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along with examples of superconducting structures for various applications.

  17. Large superconducting magnets

    CERN Document Server

    Pérot, J

    1981-01-01

    Discusses the use of large superconducting magnets in the areas of particle physics, thermonuclear fusion, and magnetohydrodynamics. In addition to considering the physics of the superconducting state, the article considers machines such as BEBC (Big European Bubble Chamber) at CERN, the LINAC at SLAC and possible Tokamak applications. The future application of superconductors to high speed trains is discussed. (0 refs).

  18. Superconducting cavities for LEP

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Above: a 350 MHz superconducting accelerating cavity in niobium of the type envisaged for accelerating electrons and positrons in later phases of LEP. Below: a small 1 GHz cavity used for investigating the surface problems of superconducting niobium. Albert Insomby stays on the right. See Annual Report 1983 p. 51.

  19. The superconducting phases of UPt3

    Science.gov (United States)

    Joynt, Robert; Taillefer, Louis

    2002-01-01

    The heavy-fermion compound UPt3 is the first compelling example of a superconductor with an order parameter of unconventional symmetry. To this day, it is the only unambiguous case of multiple superconducting phases. Twenty years of experiment and theory on the superconductivity of UPt3 are reviewed, with the aim of accounting for the multicomponent phase diagram and identifying the superconducting phases. First, the state above the superconducting critical temperature at Tc=0.5 K is briefly described: de Haas-van Alphen and other measurements demonstrate that this state is a Fermi liquid, with degeneracy fully achieved at Tc. This implies that the usual BCS theory of superconductivity should hold, although the strong magnetic interactions suggest the possibility of an unconventional superconducting order parameter. The role of the weak antiferromagnetic order below TN=5 K in causing phase multiplicity is examined. A comprehensive analysis of which superconducting states are possible is given, and the theoretical basis for each of the main candidates is considered. The behavior of various properties at low temperature (Tnodes in the superconducting gap function of all three phases. In particular, the low-temperature low-field phase has a gap with a line node in the basal plane and point nodes along the hexagonal c axis. The phase diagram in the magnetic-field-temperature plane has been determined in detail by ultrasound and thermodynamic measurements. Experiments under pressure indicate a coupling between antiferromagnetism and superconductivity and provide additional clues about the order parameter. Theoretically, Ginzburg-Landau theory is the tool that elucidates the phase diagram, while calculations of the temperature and field dependence of physical quantities have been used to compare different order parameters to experiment. On balance, the data point to a two-component order parameter belonging to either the E1g or the E2u representation, with degeneracy

  20. Modern aspects of Josephson dynamics and superconductivity electronics

    CERN Document Server

    Askerzade, Iman; Cantürk, Mehmet

    2017-01-01

    In this book new experimental investigations of properties of Josephson junctions and systems are explored with the help of recent developments in superconductivity. The theory of the Josephson effect is presented taking into account the influence of multiband and anisotropy effects in new superconducting compounds. Anharmonicity effects in current-phase relation on Josephson junctions dynamics are discussed. Recent studies in analogue and digital superconductivity electronics are presented. Topics of special interest include resistive single flux quantum logic in digital electronics. Application of Josephson junctions in quantum computing as superconducting quantum bits are analyzed. Particular attention is given to understanding chaotic behaviour of Josephson junctions and systems. The book is written for graduate students and researchers in the field of applied superconductivity.

  1. jCompoundMapper: An open source Java library and command-line tool for chemical fingerprints

    Directory of Open Access Journals (Sweden)

    Hinselmann Georg

    2011-01-01

    Full Text Available Abstract Background The decomposition of a chemical graph is a convenient approach to encode information of the corresponding organic compound. While several commercial toolkits exist to encode molecules as so-called fingerprints, only a few open source implementations are available. The aim of this work is to introduce a library for exactly defined molecular decompositions, with a strong focus on the application of these features in machine learning and data mining. It provides several options such as search depth, distance cut-offs, atom- and pharmacophore typing. Furthermore, it provides the functionality to combine, to compare, or to export the fingerprints into several formats. Results We provide a Java 1.6 library for the decomposition of chemical graphs based on the open source Chemistry Development Kit toolkit. We reimplemented popular fingerprinting algorithms such as depth-first search fingerprints, extended connectivity fingerprints, autocorrelation fingerprints (e.g. CATS2D, radial fingerprints (e.g. Molprint2D, geometrical Molprint, atom pairs, and pharmacophore fingerprints. We also implemented custom fingerprints such as the all-shortest path fingerprint that only includes the subset of shortest paths from the full set of paths of the depth-first search fingerprint. As an application of jCompoundMapper, we provide a command-line executable binary. We measured the conversion speed and number of features for each encoding and described the composition of the features in detail. The quality of the encodings was tested using the default parametrizations in combination with a support vector machine on the Sutherland QSAR data sets. Additionally, we benchmarked the fingerprint encodings on the large-scale Ames toxicity benchmark using a large-scale linear support vector machine. The results were promising and could often compete with literature results. On the large Ames benchmark, for example, we obtained an AUC ROC performance of 0

  2. Qubit compatible superconducting interconnects

    Science.gov (United States)

    Foxen, B.; Mutus, J. Y.; Lucero, E.; Graff, R.; Megrant, A.; Chen, Yu; Quintana, C.; Burkett, B.; Kelly, J.; Jeffrey, E.; Yang, Yan; Yu, Anthony; Arya, K.; Barends, R.; Chen, Zijun; Chiaro, B.; Dunsworth, A.; Fowler, A.; Gidney, C.; Giustina, M.; Huang, T.; Klimov, P.; Neeley, M.; Neill, C.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T. C.; Martinis, John M.

    2018-01-01

    We present a fabrication process for fully superconducting interconnects compatible with superconducting qubit technology. These interconnects allow for the three dimensional integration of quantum circuits without introducing lossy amorphous dielectrics. They are composed of indium bumps several microns tall separated from an aluminum base layer by titanium nitride which serves as a diffusion barrier. We measure the whole structure to be superconducting (transition temperature of 1.1 K), limited by the aluminum. These interconnects have an average critical current of 26.8 mA, and mechanical shear and thermal cycle testing indicate that these devices are mechanically robust. Our process provides a method that reliably yields superconducting interconnects suitable for use with superconducting qubits.

  3. Superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Mijatovic, Nenad; Seiler, Eugen

    2010-01-01

    We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future...... offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However......, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10...

  4. Characterization of Chemical Compounds with Antioxidant and Cytotoxic Activities in Bougainvillea x buttiana Holttum and Standl, (var. Rose Extracts

    Directory of Open Access Journals (Sweden)

    Rodolfo Abarca-Vargas

    2016-12-01

    Full Text Available Bougainvillea is widely used in traditional Mexican medicine to treat several diseases. This study was designed to characterize the chemical constituents of B. x buttiana extracts with antioxidant and cytotoxic activities using different solvents. The extraction solvents used were as follows: distilled water (dH2O, methanol (MeOH, acetone (DMK, ethanol (EtOH, ethyl acetate (EtOAc, dichloromethane (DCM, and hexane (Hex (100% at an extraction temperature of 26 °C. Analysis of bioactive compounds present in the B. x buttiana extracts included the application of common phytochemical screening assays, GC-MS analysis, and cytotoxicity and antioxidant assays. The results show that the highest extraction yield was observed with water and methanol. The maximum total phenolic content amount and highest antioxidant potential were obtained when extraction with methanol was used. With the exceptions of water and ethanol extractions, all other extracts showed cytotoxicity ranging between 31% and 50%. The prevailing compounds in water, methanol, ethanol, and acetone solvents were as follows: 4H-pyran-4-one, 2,3-dihydro-3, 5-dihydroxy-6-methyl (2, 2-propenoic acid, 3-(2-hydrophenyl-(E- (3, and 3-O-methyl-d-glucose (6. By contrast, the major components in the experiments using solvents such as EtOH, DMK, EtOAc, DCM, and Hex were n-hexadecanoic acid (8, 9,12-octadecadienoic acid (Z,Z (12; 9-octadecenoic acid (E- (13, and stigmasta-5,22-dien-3-ol (28.

  5. Superconductivity and the Periodic Table

    International Nuclear Information System (INIS)

    Chapnik, I.M.

    1985-01-01

    In view of the inability of the present theory of superconductivity to make reliable predictions for the magnitude of Tsub(c) it seems useful to search for empirical relationships between the composition of the compound and the Tsub(c) value. Table I gives a list of the available Tsub(c) data for transition metals (TM) having from 3 to 9 outer electrons and Tsub(c) data for non-transition elements (NTE) of groups IIB, IIIB and IVB, including data for amorphous (Am) structures and structures (marked by triangles) obtained at high pressures. The analogous metals have therefore the same structure. In Tables II to IV the Tsub(c) data are presented for analogous compounds of NTE from IB - VIB group. Conclusions are presented. (author)

  6. Chemomics-based marker compounds mining and mimetic processing for exploring chemical mechanisms in traditional processing of herbal medicines, a continuous study on Rehmanniae Radix.

    Science.gov (United States)

    Zhou, Li; Xu, Jin-Di; Zhou, Shan-Shan; Shen, Hong; Mao, Qian; Kong, Ming; Zou, Ye-Ting; Xu, Ya-Yun; Xu, Jun; Li, Song-Lin

    2017-12-29

    Exploring processing chemistry, in particular the chemical transformation mechanisms involved, is a key step to elucidate the scientific basis in traditional processing of herbal medicines. Previously, taking Rehmanniae Radix (RR) as a case study, the holistic chemome (secondary metabolome and glycome) difference between raw and processed RR was revealed by integrating hyphenated chromatographic techniques-based targeted glycomics and untargeted metabolomics. Nevertheless, the complex chemical transformation mechanisms underpinning the holistic chemome variation in RR processing remain to be extensively clarified. As a continuous study, here a novel strategy by combining chemomics-based marker compounds mining and mimetic processing is proposed for further exploring the chemical mechanisms involved in herbal processing. First, the differential marker compounds between raw and processed herbs were rapidly discovered by untargeted chemomics-based mining approach through multivariate statistical analysis of the chemome data obtained by integrated metabolomics and glycomics analysis. Second, the marker compounds were mimetically processed under the simulated physicochemical conditions as in the herb processing, and the final reaction products were chemically characterized by targeted chemomics-based mining approach. Third, the main chemical transformation mechanisms involved were clarified by linking up the original marker compounds and their mimetic processing products. Using this strategy, a set of differential marker compounds including saccharides, glycosides and furfurals in raw and processed RR was rapidly found, and the major chemical mechanisms involved in RR processing were elucidated as stepwise transformations of saccharides (polysaccharides, oligosaccharides and monosaccharides) and glycosides (iridoid glycosides and phenethylalcohol glycosides) into furfurals (glycosylated/non-glycosylated hydroxymethylfurfurals) by deglycosylation and/or dehydration. The

  7. Superconductivity in aromatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Kubozono, Yoshihiro, E-mail: kubozono@cc.okayama-u.ac.jp [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Japan Science and Technology Agency, ACT-C, Kawaguchi 332-0012 (Japan); Goto, Hidenori; Jabuchi, Taihei [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Yokoya, Takayoshi [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Research Center of New Functional Materials for Energy Production, Storage and Transport, Okayama University, Okayama 700-8530 (Japan); Kambe, Takashi [Department of Physics, Okayama University, Okayama 700-8530 (Japan); Sakai, Yusuke; Izumi, Masanari; Zheng, Lu; Hamao, Shino; Nguyen, Huyen L.T. [Research Laboratory for Surface Science, Okayama University, Okayama 700-8530 (Japan); Sakata, Masafumi; Kagayama, Tomoko; Shimizu, Katsuya [Center of Science and Technology under Extreme Conditions, Osaka University, Osaka 560-8531 (Japan)

    2015-07-15

    Highlights: • Aromatic superconductor is one of core research subjects in superconductivity. Superconductivity is observed in certain metal-doped aromatic hydrocarbons. Some serious problems to be solved exist for future advancement of the research. This article shows the present status of aromatic superconductors. - Abstract: ‘Aromatic hydrocarbon’ implies an organic molecule that satisfies the (4n + 2) π-electron rule and consists of benzene rings. Doping solid aromatic hydrocarbons with metals provides the superconductivity. The first discovery of such superconductivity was made for K-doped picene (K{sub x}picene, five benzene rings). Its superconducting transition temperatures (T{sub c}’s) were 7 and 18 K. Recently, we found a new superconducting K{sub x}picene phase with a T{sub c} as high as 14 K, so we now know that K{sub x}picene possesses multiple superconducting phases. Besides K{sub x}picene, we discovered new superconductors such as Rb{sub x}picene and Ca{sub x}picene. A most serious problem is that the shielding fraction is ⩽15% for K{sub x}picene and Rb{sub x}picene, and it is often ∼1% for other superconductors. Such low shielding fractions have made it difficult to determine the crystal structures of superconducting phases. Nevertheless, many research groups have expended a great deal of effort to make high quality hydrocarbon superconductors in the five years since the discovery of hydrocarbon superconductivity. At the present stage, superconductivity is observed in certain metal-doped aromatic hydrocarbons (picene, phenanthrene and dibenzopentacene), but the shielding fraction remains stubbornly low. The highest priority research area is to prepare aromatic superconductors with a high superconducting volume-fraction. Despite these difficulties, aromatic superconductivity is still a core research target and presents interesting and potentially breakthrough challenges, such as the positive pressure dependence of T{sub c} that is clearly

  8. Pharmaceutically active compounds and endocrine disrupting chemicals in water, sediments and mollusks in mangrove ecosystems from Singapore.

    Science.gov (United States)

    Bayen, Stéphane; Estrada, Elvagris Segovia; Juhel, Guillaume; Kit, Lee Wei; Kelly, Barry C

    2016-08-30

    This study investigated the occurrence of bisphenol A (BPA), atrazine and selected pharmaceutically active compounds (PhACs) in mangrove habitats in Singapore in 2012-2013, using multiple tools (sediment sampling, POCIS and filter feeder molluscs). Using POCIS, the same suite of contaminants (atrazine, BPA and eleven PhACs) was detected in mangrove waters in 28-days deployments in both 2012 and 2013. POCIS concentrations ranged from pg/L to μg/L. Caffeine, BPA, carbamazepine, E1, triclosan, sulfamerazine, sulfamethazine, and lincomycin were also detected in mangrove sediments from the low pg/g dw (e.g. carbamazepine) to ng/g dw (e.g. BPA). The detection of caffeine, carbamazepine, BPA, sulfamethoxazole or lincomycin in bivalve tissues also showed that these chemicals are bioavailable in the mangrove habitat. Since there are some indications that some pharmaceutically active substances may be biologically active in the low ppb range in marine species, further assessment should be completed based on ecotoxicological data specific to mangrove species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Influence of crystal defects on the chemical reactivity of recoil atoms in oxygen-containing chromium compounds

    International Nuclear Information System (INIS)

    Costea, T.

    1969-01-01

    The influence of crystal defects on the chemical reactivity of recoil atoms produced by the reaction 50 Cr (n,γ) 51 Cr in oxygen-containing chromium compounds has been studied. Three methods have been used to introduce the defects: doping (K 2 CrO 4 doped with BaCrO 4 ), irradiation by ionizing radiation (K 2 CrO 4 irradiated in the presence of Li 2 CO 3 ) and non-stoichiometry (the semi-conducting oxides of the CrO 3 -Cr 2 O 3 series). The thermal annealing kinetics of the irradiated samples have been determined, and the activation energy has been calculated. In all cases it has been observed that there is a decrease in the activation energy for thermal annealing in the presence of the defects. In order to explain the annealing process, an electronic mechanism has been proposed based on the interaction between the recoil species and the charge-carriers (holes or electrons). (author) [fr

  10. Synthesis and investigation of the structure and chemical properties of acyclic compounds of bicoordinated phosphorus with a phosphorus-carbon (p-p)/sub π/ bond

    International Nuclear Information System (INIS)

    Markovskii, L.N.; Romanenko, V.D.

    1987-01-01

    Five types of reactions of phosphoalkenes can be distinguished according to the nature of the change in the coordination number and valence of the phosphorus atom in the course of chemical conversions. There are: reactions of cyclodimerization, cycloaddition, and 1,2-addition at the P-C double bond; formation of compounds of tricoordinated pentavalent phosphorus; formation of tetracoordinated phosphorus compounds; reactions of functionalization occurring without a change in the valence and coordination number of the phosphorus atom; and reactions of 1,2-elimination, leading to compounds of monocoordinated phosphorus. This paper reviews each of these reactions in detail, using double-resonance hydrogen 1 and phosphorus 31 NMR spectra and analyzing the acquired chemical shift and spin-spin coupling constants, and also demonstrates the complexation of phosphorus with several metals

  11. Structure–metabolism relationships in human-AOX: Chemical insights from a large database of aza-aromatic and amide compounds

    Science.gov (United States)

    Ceccarelli, Martina; Milani, Nicolò; Tortorella, Sara; Cucco, Andrea; Goracci, Laura; Brink, Andreas; Cruciani, Gabriele

    2017-01-01

    Aldehyde oxidase (AOX) is a metabolic enzyme catalyzing the oxidation of aldehyde and aza-aromatic compounds and the hydrolysis of amides, moieties frequently shared by the majority of drugs. Despite its key role in human metabolism, to date only fragmentary information about the chemical features responsible for AOX susceptibility are reported and only “very local” structure–metabolism relationships based on a small number of similar compounds have been developed. This study reports a more comprehensive coverage of the chemical space of structures with a high risk of AOX phase I metabolism in humans. More than 270 compounds were studied to identify the site of metabolism and the metabolite(s). Both electronic [supported by density functional theory (DFT) calculations] and exposure effects were considered when rationalizing the structure–metabolism relationship. PMID:28373537

  12. Superconductivity and electrical resistivity in alkali metal doped ...

    Indian Academy of Sciences (India)

    Unknown

    Fullerenes; alkali-C60 phonon; on-ball-C60 phonon; pressure effect; electrical resistivity. 1. Introduction. Buckminsterfullerenes are known to make compounds with alkali metals intensively studied mainly due to superconductivity and the variation of compounds (Hebard et al 1991; Holczer et al 1991; Tanigaki et al 1991).

  13. Magnetic nesting and co-existence of ferromagnetism and superconductivity

    International Nuclear Information System (INIS)

    Elesin, V.F.; Kapaev, V.V.; Kopaev, Yu.V.

    2004-01-01

    In the case of providing for the magnetic nesting conditions of the electron spin dispersion law the co-existence of ferromagnetism and superconductivity is possible by any high magnetization. The co-existence of ferromagnetism and superconductivity in the layered cuprate compounds of the RuSr 2 GdCu 2 O 8 -type is explained on this basis, wherein due to the nonstrict provision of the magnetic nesting condition there exists the finite but sufficiently high critical magnetization [ru

  14. Multi-label classifier based on histogram of gradients for predicting the anatomical therapeutic chemical class/classes of a given compound.

    Science.gov (United States)

    Nanni, Loris; Brahnam, Sheryl

    2017-09-15

    Given an unknown compound, is it possible to predict its Anatomical Therapeutic Chemical class/classes? This is a challenging yet important problem since such a prediction could be used to deduce not only a compound's possible active ingredients but also its therapeutic, pharmacological and chemical properties, thereby substantially expediting the pace of drug development. The problem is challenging because some drugs and compounds belong to two or more ATC classes, making machine learning extremely difficult. In this article a multi-label classifier system is proposed that incorporates information about a compound's chemical-chemical interaction and its structural and fingerprint similarities to other compounds belonging to the different ATC classes. The proposed system reshapes a 1D feature vector to obtain a 2D matrix representation of the compound. This matrix is then described by a histogram of gradients that is fed into a Multi-Label Learning with Label-Specific Features classifier. Rigorous cross-validations demonstrate the superior prediction quality of this method compared with other state-of-the-art approaches developed for this problem, a superiority that is reflected particularly in the absolute true rate, the most important and harshest metric for assessing multi-label systems. The MATLAB code for replicating the experiments presented in this article is available at https://www.dropbox.com/s/7v1mey48tl9bfgz/ToolPaperATC.rar?dl=0 . loris.nanni@unipd.it. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  15. Introduction to superconductivity

    CERN Document Server

    Darriulat, Pierre

    1998-01-01

    The lecture series will address physicists, such as particle and nuclear physicists, familiar with non-relativistic quantum mechanics but not with solid state physics. The aim of this introduction to low temperature superconductivity is to give sufficient bases to the student for him/her to be able to access the scientific literature on this field. The five lectures will cover the following topics : 1. Normal metals, free electron gas, chambers equation. 2. Cooper pairs, the BCS ground state, quasi particle excitations. 3. DC superconductivity, Meissner state, dirty superconductors.4. Self consistent approach, Ginsburg Landau equations, Abrikosov fluxon lattice. 5. Josephson effects, high temperature superconductivity.

  16. Superconducting tin core fiber

    Energy Technology Data Exchange (ETDEWEB)

    Homa, Daniel; Liang, Yongxuan; Hill, Cary; Kaur, Gurbinder; Pickrell, Gary [Virginia Polytechnic Institute and State University, Department of Materials Science and Engineering, Blacksburg, VA (United States)

    2014-11-13

    In this study, we demonstrated superconductivity in a fiber with a tin core and fused silica cladding. The fibers were fabricated via a modified melt-draw technique and maintained core diameters ranging from 50-300 microns and overall diameters of 125-800 microns. Superconductivity of this fiber design was validated via the traditional four-probe test method in a bath of liquid helium at temperatures on the order of 3.8 K. The synthesis route and fiber design are perquisites to ongoing research dedicated all-fiber optoelectronics and the relationships between superconductivity and the material structures, as well as corresponding fabrication techniques. (orig.)

  17. Superconducting tin core fiber

    International Nuclear Information System (INIS)

    Homa, Daniel; Liang, Yongxuan; Hill, Cary; Kaur, Gurbinder; Pickrell, Gary

    2015-01-01

    In this study, we demonstrated superconductivity in a fiber with a tin core and fused silica cladding. The fibers were fabricated via a modified melt-draw technique and maintained core diameters ranging from 50-300 microns and overall diameters of 125-800 microns. Superconductivity of this fiber design was validated via the traditional four-probe test method in a bath of liquid helium at temperatures on the order of 3.8 K. The synthesis route and fiber design are perquisites to ongoing research dedicated all-fiber optoelectronics and the relationships between superconductivity and the material structures, as well as corresponding fabrication techniques. (orig.)

  18. The chronicle of superconductivity

    International Nuclear Information System (INIS)

    Bassalo, J.M.F.

    1981-01-01

    The chronicle of the superconductivity is shown, since the first observation made of Kamerlingh-Onnes, in the begining of our century about superconductivity effects, by describing several models and theories made by the physicists, by trying to explain the phenomenons referred about supercurrent, up to the modern BCS Theory. Our fundamental purpose rather than to make a historical-philosophical evolution about the superconductivity is only to make a sequence as who made what, when and how, by using the Solla-Price meaning. (Author) [pt

  19. Superconductivity in doped insulators

    International Nuclear Information System (INIS)

    Emery, V.J.; Kivelson, S.A.

    1995-01-01

    It is shown that many synthetic metals, including high temperature superconductors are ''bad metals'', with such a poor conductivity that the usual meanfield theory of superconductivity breaks down because of anomalously large classical and quantum fluctuations of the phase of the superconducting order parameter. It is argued that the supression of a first order phase transition (phase separation) by the long-range Coulomb interaction leads to high temperature superconductivity accompanied by static or dynamical charge inhomogeneIty. Evidence in support of this picture for high temperature superconductors is described

  20. Superconducting materials and magnets

    International Nuclear Information System (INIS)

    1991-04-01

    The Technical Committee Meeting on Superconducting Materials and Magnets was convened by the IAEA and held by invitation of the Japanese government on September 4-6, 1989 in Tokyo. The meeting was hosted by the National Research Institute for Metals. Topics of the conference related to superconducting magnets and technology with particular application to fusion and the superconducting supercollider. Technology using both high and low-temperature superconductors was discussed. This document is a compendium of the papers presented at the meeting. Refs, figs and tabs

  1. 'Speedy' superconducting circuits

    International Nuclear Information System (INIS)

    Holst, T.

    1994-01-01

    The most promising concept for realizing ultra-fast superconducting digital circuits is the Rapid Single Flux Quantum (RSFQ) logic. The basic physical principle behind RSFQ logic, which include the storage and transfer of individual magnetic flux quanta in Superconducting Quantum Interference Devices (SQUIDs), is explained. A Set-Reset flip-flop is used as an example of the implementation of an RSFQ based circuit. Finally, the outlook for high-temperature superconducting materials in connection with RSFQ circuits is discussed in some details. (au)

  2. Determination of the bioactive compounds, antioxidant activity and chemical composition of Brazilian blackberry, red raspberry, strawberry, blueberry and sweet cherry fruits.

    Science.gov (United States)

    de Souza, Vanessa Rios; Pereira, Patrícia Aparecida Pimenta; da Silva, Thais Lomônaco Teodoro; de Oliveira Lima, Luiz Carlos; Pio, Rafael; Queiroz, Fabiana

    2014-08-01

    This study aimed to evaluate the chemical composition, identify the bioactive compounds and measure the antioxidant activity present in blackberry, red raspberry, strawberry, sweet cherry and blueberry fruits produced in the subtropical areas of Brazil and to verify that the chemical properties of these fruit are similar when compared to the temperate production zones. Compared with berries and cherries grown in temperate climates, the centesimal composition and physical chemical characteristics found in the Brazilian berries and cherries are in agreement with data from the literature. For the mineral composition, the analyzed fruits presented lower concentrations of P, K, Ca, Mg and Zn and higher levels of Fe. The values found for the bioactive compounds generally fit the ranges reported in the literature with minor differences. The greatest difference was found in relation to ascorbic acid, as all fruits analyzed showed levels well above those found in the literature. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Analysis of air-, moisture- and solvent-sensitive chemical compounds by mass spectrometry using an inert atmospheric pressure solids analysis probe.

    Science.gov (United States)

    Mosely, Jackie A; Stokes, Peter; Parker, David; Dyer, Philip W; Messinis, Antonis M

    2018-02-01

    A novel method has been developed that enables chemical compounds to be transferred from an inert atmosphere glove box and into the atmospheric pressure ion source of a mass spectrometer whilst retaining a controlled chemical environment. This innovative method is simple and cheap to implement on some commercially available mass spectrometers. We have termed this approach inert atmospheric pressure solids analysis probe ( iASAP) and demonstrate the benefit of this methodology for two air-/moisture-sensitive chemical compounds whose characterisation by mass spectrometry is now possible and easily achieved. The simplicity of the design means that moving between iASAP and standard ASAP is straightforward and quick, providing a highly flexible platform with rapid sample turnaround.

  4. A relationship between ion balance and the chemical compounds of salt inclusions found in the Greenland Ice Core Project and Dome Fuji ice cores

    DEFF Research Database (Denmark)

    Johnsen, Sigfus Johann; Dahl-Jensen, Dorthe; Steffensen, Jørgen Peder

    2008-01-01

    on individual salt inclusions. The abundances in the ice cores are shown to reflect differences in climatic periods (the acidic environment of the Holocene versus the reductive environment of the last glacial maximum) and regional conditions (the marine environment of Antarctica versus the continental......We have proposed a method of deducing the chemical compounds found in deep polar ice cores by analyzing the balance between six major ions (Cl-, NO3 -, SO4 2-, Na+, Mg2+, and Ca2+). The method is demonstrated for the Holocene and last glacial maximum regions of the Dome Fuji and GRIP ice cores....... The dominant compounds depend only on the ion balance and the sequence of chemical reactions. In priority order, the principle salts are calcium sulfate, other sulfates, nitrate, chloride, and carbonate. The chemical abundances deduced by this method agree well with the results of Raman spectroscopy...

  5. Study of some superconducting and magnetic materials on high T sub c oxide superconductors

    Science.gov (United States)

    Wu, M. K.

    1987-01-01

    On the basis of existing data it appears that the high-temperature superconductivity above 77 K reported here, occurs only in compound systems consisting of a phase other than the K2NiF4 phase. A narrow superconducting transition was obtained with T sub c0 = 98 K and T sub c1 = 94 K in Y-Ba-Cu-O (YBCO). Preliminary results indicate that YBCO is rather different from the layered LaBCO, LaSCO, and LaCCO. While electron-photon interaction cannot be absent from this compound system, nonconventional enhanced superconducting interactions due to interfaces, Resonating Valence Bond (RVB) states, or even a superconducting state beyond the BCS framework, may be required to account for the high T sub c in YBCO. It is believed that study of the possible subtle correlation between magnetism and superconductivity will definitely provide important insight into the superconducting mechanism in YBCO and other oxides.

  6. Superconducting Technology Assessment

    National Research Council Canada - National Science Library

    2005-01-01

    This Superconducting Technology Assessment (STA) has been conducted by the National Security Agency to address the fundamental question of a potential replacement for silicon complementary metal oxide semiconductor (CMOS...

  7. Superconductivity and its devices

    International Nuclear Information System (INIS)

    Forbes, D.S.

    1981-01-01

    Among the more important developments that are discussed are cryotrons, superconducting motors and generators, and high-field magnets. Cryotrons will create faster and more economical computer systems. Superconducting motors and generators will cost much less to build than conventional electric generators and cut fuel consumption. Moreover, high-field magnets are being used to confine plasma in connection with nuclear fusion. Superconductors have a vital role to play in all of these developments. Most importantly, though, are the magnetic properties of superconductivity. Superconducting magnets are an integral part of nuclear fusion. In addition, high-field magnets are necessary in the use of accelerators, which are needed to study the interactions between elementary particles

  8. Superconductivity: Heike's heritage

    NARCIS (Netherlands)

    van der Marel, D.; Golden, M.

    2011-01-01

    A century ago, Heike Kamerlingh Onnes discovered superconductivity. And yet, despite the conventional superconductors being understood, the list of unconventional superconductors is growing — for which unconventional theories may be required.

  9. Magnetic and superconducting nanowires

    DEFF Research Database (Denmark)

    Piraux, L.; Encinas, A.; Vila, L.

    2005-01-01

    magnetic and superconducting nanowires. Using different approaches entailing measurements on both single wires and arrays, numerous interesting physical properties have been identified in relation to the nanoscopic dimensions of these materials. Finally, various novel applications of the nanowires are also...

  10. Industrial applied superconductivity

    International Nuclear Information System (INIS)

    Sabrie, J.L.

    1984-01-01

    This paper reviews the main applications of superconductivity in D.C. in variable current and in A.C. The existing markets are now worth the effort of producing commercial superconductors and of developing applications [fr

  11. Structural and chemical evolution of propionate based metal-organic precursors for superconducting YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} epitaxial film growth

    Energy Technology Data Exchange (ETDEWEB)

    Armenio, A Angrisani; Augieri, A; Galluzzi, V; Mancini, A; Rufoloni, A; Vannozzi, A; Celentano, G [Associazione EURATOM-ENEA sulla Fusione, Frascati Research Centre, Via E Fermi, 45, 00044 Frascati (Rome) (Italy); Ciontea, L; Petrisor, T [Technical University of Cluj-Napoca, Str. C. Daicoviciu 15, 3400 Cluj-Napoca (Romania); Contini, G; Giovannantonio, M Di [Istituto di Struttura della Materia-CNR, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Davoli, I, E-mail: giorgio.contini@ism.cnr.it, E-mail: giuseppe.celentano@enea.it [Universita di Roma ' Tor Vergata' , Via della Ricerca Scientifica 1, 00133 Rome (Italy)

    2011-11-15

    The structural and chemical evolution of propionate based low fluorine YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) precursor during the conversion thermal treatment to obtain superconducting film has been investigated by both x-ray photoelectron and diffraction techniques in a set of partially converted films on SrTiO{sub 3} single crystals. The pyrolysis temperature within the range 400-480 deg. C mainly affects the copper valence state with an increase of the Cu{sup 2+} fraction with temperature with respect to the Cu{sup 1+} oxidation state. During the subsequent thermal treatment up to 700 deg. C, the reduction of fluorine content is mainly ascribed to the hydrolysis of YF{sub 3}. At higher temperatures, Ba hydrolysis, Y{sub 2}Cu{sub 2}O{sub 5} and YBCO phase formation (nucleation at 700 deg. C and 725 deg. C, respectively) have been observed. The temperature dependences of the formation and decomposition of YBCO, Y{sub 2}Cu{sub 2}O{sub 5} and Ba-oxyfluoride were evaluated by x-ray diffraction measurements. The reaction path emerging from these analyses agrees with the one observed for YBCO films obtained with the standard MOD method based on metal tri-fluoroacetate precursors.

  12. Superconducting Wind Turbine Generators

    OpenAIRE

    Yunying Pan; Danhzen Gu

    2016-01-01

    Wind energy is well known as a renewable energy because its clean and less polluted characteristic, which is the foundation of development modern wind electricity. To find more efficient wind turbine is the focus of scientists around the world. Compared from conventional wind turbines, superconducting wind turbine generators have advantages at zero resistance, smaller size and lighter weight. Superconducting wind turbine will inevitably become the main trends in this area. This paper intends ...

  13. Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

    Science.gov (United States)

    Yuan, Bin; Coggon, Matthew M.; Koss, Abigail R.; Warneke, Carsten; Eilerman, Scott; Peischl, Jeff; Aikin, Kenneth C.; Ryerson, Thomas B.; de Gouw, Joost A.

    2017-04-01

    Concentrated animal feeding operations (CAFOs) emit a large number of volatile organic compounds (VOCs) to the atmosphere. In this study, we conducted mobile laboratory measurements of VOCs, methane (CH4) and ammonia (NH3) downwind of dairy cattle, beef cattle, sheep and chicken CAFO facilities in northeastern Colorado using a hydronium ion time-of-flight chemical-ionization mass spectrometer (H3O+ ToF-CIMS), which can detect numerous VOCs. Regional measurements of CAFO emissions in northeastern Colorado were also performed using the NOAA WP-3D aircraft during the Shale Oil and Natural Gas Nexus (SONGNEX) campaign. Alcohols and carboxylic acids dominate VOC concentrations and the reactivity of the VOCs with hydroxyl (OH) radicals. Sulfur-containing and phenolic species provide the largest contributions to the odor activity values and the nitrate radical (NO3) reactivity of VOC emissions, respectively. VOC compositions determined from mobile laboratory and aircraft measurements generally agree well with each other. The high time-resolution mobile measurements allow for the separation of the sources of VOCs from different parts of the operations occurring within the facilities. We show that the emissions of ethanol are primarily associated with feed storage and handling. Based on mobile laboratory measurements, we apply a multivariate regression analysis using NH3 and ethanol as tracers to determine the relative importance of animal-related emissions (animal exhalation and waste) and feed-related emissions (feed storage and handling) for different VOC species. Feed storage and handling contribute significantly to emissions of alcohols, carbonyls, carboxylic acids and sulfur-containing species. Emissions of phenolic species and nitrogen-containing species are predominantly associated with animals and their waste.

  14. The use of a housecleaning product in an indoor environment leading to oxygenated polar compounds and SOA formation: Gas and particulate phase chemical characterization

    Science.gov (United States)

    Rossignol, S.; Rio, C.; Ustache, A.; Fable, S.; Nicolle, J.; Même, A.; D'Anna, B.; Nicolas, M.; Leoz, E.; Chiappini, L.

    2013-08-01

    This work investigates Secondary Organic Aerosol (SOA) formed by limonene ozonolysis using a housecleaning product in indoor environment. This study combines simulation chamber ozonolysis experiments and field studies in an experimental house allowing different scenarios of housecleaning product use in real conditions. Chemical speciation has been performed using a new method based on simultaneous sampling of both gas and particulate phases on sorbent tubes and filters. This method allowed the identification and quantification of about 35 products in the gas and particulate phases. Among them, products known to be specific from limonene ozonolysis such as limononaldehyde, ketolimonene and ketolimonic acid have been detected. Some other compounds such as 2-methylbutanoic acid had never been detected in previous limonene ozonolysis studies. Some compounds like levulinic acid had already been detected but their formation remained unexplained. Potential reaction pathways are proposed in this study for these compounds. For each experiment, chemical data are coupled together with physical characterization of formed particles: mass and size and number distribution evolution which allowed the observation of new particles formation (about 87,000 particle cm-3). The chemical speciation associated to aerosol size distribution results confirmed that limonene emitted by the housecleaning product was responsible for SOA formation. To our knowledge, this work provides the most comprehensive analytical study of detected compounds in a single experiment for limonene ozonolysis in both gaseous and particulate phases in real indoor environment.

  15. Superconducting Fullerene Nanowhiskers

    Directory of Open Access Journals (Sweden)

    Yoshihiko Takano

    2012-04-01

    Full Text Available We synthesized superconducting fullerene nanowhiskers (C60NWs by potassium (K intercalation. They showed large superconducting volume fractions, as high as 80%. The superconducting transition temperature at 17 K was independent of the K content (x in the range between 1.6 and 6.0 in K-doped C60 nanowhiskers (KxC60NWs, while the superconducting volume fractions changed with x. The highest shielding fraction of a full shielding volume was observed in the material of K3.3C60NW by heating at 200 °C. On the other hand, that of a K-doped fullerene (K-C60 crystal was less than 1%. We report the superconducting behaviors of our newly synthesized KxC60NWs in comparison to those of KxC60 crystals, which show superconductivity at 19 K in K3C60. The lattice structures are also discussed, based on the x-ray diffraction (XRD analyses.

  16. Electron pairing without superconductivity

    Science.gov (United States)

    Levy, Jeremy

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances--paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity. Support from AFOSR, ONR, ARO, NSF, DOE and NSSEFF is gratefully acknowledged.

  17. Emergent Higgsless Superconductivity

    Directory of Open Access Journals (Sweden)

    Cristina Diamantini M.

    2017-01-01

    Full Text Available We present a new Higgsless model of superconductivity, inspired from anyon superconductivity but P- and T-invariant and generalizable to any dimension. While the original anyon superconductivity mechanism was based on incompressible quantum Hall fluids as average field states, our mechanism involves topological insulators as average field states. In D space dimensions it involves a (D-1-form fictitious pseudovector gauge field which originates from the condensation of topological defects in compact lowenergy effective BF theories. There is no massive Higgs scalar as there is no local order parameter. When electromagnetism is switched on, the photon acquires mass by the topological BF mechanism. Although the charge of the gapless mode (2 and the topological order (4 are the same as those of the standard Higgs model, the two models of superconductivity are clearly different since the origins of the gap, reflected in the high-energy sectors are totally different. In 2D thi! s type of superconductivity is explicitly realized as global superconductivity in Josephson junction arrays. In 3D this model predicts a possible phase transition from topological insulators to Higgsless superconductors.

  18. Microstructural and superconducting properties of high current metal-organic chemical vapor deposition YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} coated conductor wires

    Energy Technology Data Exchange (ETDEWEB)

    Holesinger, T G; Maiorov, B; Ugurlu, O; Civale, L [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Chen, Y; Xiong, X; Xie, Y; Selvamanickam, V [SuperPower, Inc., Schenectady, NY 12304 (United States)

    2009-04-15

    Metal-organic chemical vapor deposition (MOCVD) on flexible, ion beam assisted deposition MgO templates has been used to produce high critical current density (J{sub c}) (Y,Sm){sub 1}Ba{sub 2}Cu{sub 3}O{sub y} (REBCO) films suitable for use in producing practical high temperature superconducting (HTS) coated conductor wires. Thick films on tape were produced with sequential additions of 0.7 {mu}m of REBCO via a reel-to-reel progression through a custom-designed MOCVD reactor. Multi-pass processing for thick film deposition is critically dependent upon minimizing surface secondary phase formation. Critical currents (I{sub c}s) of up to 600 A/cm width (t = 2.8 {mu}m, J{sub c} = 2.6 MA cm{sup -2}, 77 K, self-field) were obtained in short lengths of HTS wires. These high performance MOCVD films are characterized by closely spaced (Y,Sm){sub 2}O{sub 3} nanoparticle layers that may be tilted relative to the film normal and REBCO orientation. Small shifts in the angular dependence of J{sub c} in low and intermediate applied magnetic fields can be associated with the tilted nanoparticle layers. Also present in these films were YCuO{sub 2} nanoplates aligned with the YBCO matrix (short dimension perpendicular to the film normal), threading dislocations, and oriented composite defects (OCDs). The latter structures consist of single or multiple a-axis oriented grains coated on each side with insulating (Y,Sm){sub 2}O{sub 3} or CuO. The OCDs formed a connected network of insulating phases by the end of the fourth pass. Subsequent attempts at adding additional layers did not increase I{sub c}. There is an inconsistency between the measured J{sub c} and the observed microstructural degradation that occurs with each additional layer, suggesting that previously deposited layers are improving with each repeated reactor pass. These dynamic changes suggest a role for post-processing to optimize superconducting properties of as-deposited films, addressing issues associated with

  19. Evaluating Occupational Exposure to Carcinogenic Volatile Organic Compounds in an Oil-Dependent Chemical Industry: a Case Study on Benzen and Epichlorohydrin

    Directory of Open Access Journals (Sweden)

    Amir Reza Negahban

    2014-04-01

    Full Text Available Background & Objectives: Exposure of workers to carcinogenic compounds in chemical industries during a long period might cause irreversible health effects. This study evaluated workers exposure to benzene and epichlorohydrin in breathing air in one of the oil-dependent chemical industries of Iran. Methods: This descriptive-analytic study was performed in one of the oil-dependent chemical industries of south of Iran, winter, 2012. A total of 173 workers were examined in this study. NIOSH 1501 and 1010 methods were used to assess personal exposure to benzene and epichlorohydrin, correspondingly. Collected samples were analyzed with gas chromatography-mass spectrophotometry method. Results: Among 346 collected samples, benzene was identified in all cases (100% and epichlorohydrin in 156 samples (45%. A significant difference was found in the mean of exposure to benzene and epichlorohydrin in various workshops (Pvalue 0.05. Conclusion: It seems that work nature of employees in chemical industry affects their exposure to volatile organic compounds in workplace. According to the results, due to the proximity of compounds concentration to the action level, especially benzene and also the workers exposure to less than the maximum limit in the long-term, reducing exposure through appropriate control measures are necessary.

  20. Other compounds isolated from Simira glaziovii and the {sup 1}H and {sup 13}C NMR chemical shift assignments of new 1-epi-castanopsol

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Marcelo F. de; Vieira, Ivo J. Curcino [Universidade Federal Rural do Rio de Janeiro, Seropedica, RJ (Brazil). Dept. de Quimica; Braz-Filho, Raimundo [Universidade Estadual do Norte Fluminense (UENF), Campos dos Goytacases, RJ (Brazil). Centro de Ciencias Tecnologicas. Lab. de Ciencias Quimicas; Carvalho, Mario G. de, E-mail: mgeraldo@ufrrj.br [Universidade Federal do Rio de Janeiro (NPPN/UFRJ), RJ (Brazil). Centro de Ciencias da Saude. Nucleo de Pesquisa em Produtos Naturais

    2012-07-01

    A new triterpene, 1-epi-castanopsol, besides eleven known compounds: sitosterol, stigmasterol, campesterol, lupeol, lupenone, simirane B, syringaresinol, scopoletin, isofraxidin, 6,7,8-trimethoxycoumarin and harman, were isolated from the wood of Simira glaziovii. The structures of the known compounds were defined by 1D, 2D {sup 1}H, {sup 13}C NMR spectra data analyses and comparison with literature data. The detailed spectral data analyses allowed the definition of the structure of the new 1-epi isomer of castanopsol and performance of {sup 1}H and {sup 13}C NMR chemical shift assignments. (author)

  1. Study of the relationship between chemical structure and antimicrobial activity in a series of hydrazine-based coordination compounds.

    Science.gov (United States)

    Dobrova, B N; Dimoglo, A S; Chumakov, Y M

    2000-08-01

    The dependence of antimicrobial activity on the structure of compounds is studied in a series of compounds based on hydrazine coordinated with ions of Cu(II), Ni(II) and Pd(II). The study has been carried out by means of the original electron-topological method developed earlier. A molecular fragment has been found that is only characteristic of biologically active compounds. Its spatial and electron parameters have been used for the quantitative assessment of the activity in view. The results obtained can be used for the antimicrobial activity prediction in a series of compounds with similar structures.

  2. Reducing excess sludge in a biological treatment system using chemical compounds; Reduccion de fangos en exceso de un sistema biologico de depuracion mediante el empleo de compuestos quimicos

    Energy Technology Data Exchange (ETDEWEB)

    Aragon Cruz, C.; Quiroga Alonso, J. M.; Coello Oviedo, M. D.

    2009-07-01

    In the active sludge treatment of waste water, the generation of residual sludge is a major proble due to the cost of dealing with it and the dwindling number of place for disposing of it. A proposal is made for minimising the amount of excess sludge generated using chemical compounds that uncouple its metabolism. An assessment is made of the effectiveness of four such chemical compounds, two organic (2,4-dinitrophenol DNP-and 3,3', 4',5-tetrachlorosalicylanilide- TCS) and two metals (copper and zinc) in order to obtain the optimum amount required. It was found that both TCS and zinc can reduce the bacteria growth rate (Yobs) by over 30% without hardly affecting the elimination organic matter. (Author) 22 refs.

  3. Behavior of radon, chemical compounds and stable elements in underground water; Comportamiento de radon, compuestos quimicos y elementos estables en agua subterranea

    Energy Technology Data Exchange (ETDEWEB)

    Lopez R, N.; Segovia, N.; Lopez, M.B.E.; Pena, P. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Armienta, M.A.; Godinez, L. [IGFUNAM, Ciudad Universitaria, 04510 Mexico D.F. (Mexico); Seidel, J.L. [ISTEEM, M.S.E. Montpellier (France)

    2001-07-01

    The radon behavior, chemical compounds, major and trace elements in water samples of four springs and three wells of urban and agricultural zones around the Jocotitlan volcano and El Oro region was determined, both of them located in the medium part of the Mexican neo-volcanic axis. The {sup 222} Rn was measured by the liquid scintillation method, the analysis of major components was realized with conventional chemical techniques, while the trace elements were quantified using an Icp-Ms. The average values of the radon concentrations obtained during one year were constant relatively, in an interval from 0.97 to 4.99 Bq/lt indicating a fast transport from the reload area toward the sampling points. the compounds, major and trace elements showed differences which indicate distinct origins of water from the site studies. (Author)

  4. Electron–phonon superconductivity in YIn3

    International Nuclear Information System (INIS)

    Billington, D; Llewellyn-Jones, T M; Maroso, G; Dugdale, S B

    2013-01-01

    First-principles calculations of the electron–phonon coupling were performed on the cubic intermetallic compound YIn 3 . The electron–phonon coupling constant was found to be λ ep = 0.42. Using the Allen–Dynes formula with a Coulomb pseudopotential of μ* = 0.10, a T c of approximately 0.77 K is obtained which is reasonably consistent with the experimentally observed temperature (between 0.8 and 1.1 K). The results indicate that conventional electron–phonon coupling is capable of producing the superconductivity in this compound. (paper)

  5. Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L.; Smith, Charles D. [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC (United States); Lemasters, John J., E-mail: JJLemasters@musc.edu [Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC (United States); Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC (United States)

    2013-11-15

    Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 μM of each tetracycline-derived compound 20 min prior to exposure to 500 μM iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs–Ringer–HEPES buffer at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca{sup 2+} uptake was measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometry was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca{sup 2+} uptake and suppressed the Ca{sup 2+}-induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca{sup 2+} uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition, could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU. - Highlights: • Minocycline and doxycycline are the only cytoprotective tetracyclines of those tested • Cytoprotective tetracyclines inhibit the MPT and mitochondrial calcium and iron uptake. • Cytoprotective

  6. Quantum Chemical and Experimental Studies on the Mechanism of Alkylation of β-Dicarbonyl Compounds. The Synthesis of Five and Six Membered Heterocyclic Spiro Derivatives

    Directory of Open Access Journals (Sweden)

    Ali Hüseyinli

    2004-11-01

    Full Text Available The alkylation of β-dicarbonyl compounds in a K2CO3/DMSO system wasfound to afford O- and C-alkylated derivatives, depending on the type of the β-dicarbonylcompound involved. The alkyl derivatives obtained were used in the synthesis of some newspiro barbituric acid derivatives. Quantum chemical calculations were carried out toelucidate the reaction mechanisms for some typical synthesis.

  7. Using the chemical equilibrium partitioning space to explore factors influencing the phase distribution of compounds involved in secondary organic aerosol formation

    OpenAIRE

    F. Wania; Y. D. Lei; C. Wang; J. P. D. Abbatt; K.-U. Goss

    2014-01-01

    Many atmospheric and chemical variables influence the partitioning equilibrium between gas phase and condensed phases of compounds implicated in the formation of secondary organic aerosol (SOA). The large number of factors and their interaction makes it often difficult to assess their relative importance and concerted impact. Here we introduce a two-dimensional space, which maps regions of dominant atmospheric phase distribution within a coordinate system de...

  8. Using the chemical equilibrium partitioning space to explore factors influencing the phase distribution of compounds involved in secondary organic aerosol formation

    OpenAIRE

    Wania, F.; Lei, Y. D.; Wang, C.; Abbatt, J. P. D.; Goss, K.-U.

    2015-01-01

    Many atmospheric and chemical variables influence the partitioning equilibrium between gas phase and condensed phases of compounds implicated in the formation of secondary organic aerosol (SOA). The large number of factors and their interaction makes it often difficult to assess their relative importance and concerted impact. Here we introduce a two-dimensional space which maps regions of dominant atmospheric phase distribution within a coordinate system defined by equilibri...

  9. Assessment of multi-chemical pollution in aquatic ecosystems using toxic units: compound prioritization, mixture characterization and relationships with biological descriptors.

    Science.gov (United States)

    Ginebreda, Antoni; Kuzmanovic, Maja; Guasch, Helena; de Alda, Miren López; López-Doval, Julio C; Muñoz, Isabel; Ricart, Marta; Romaní, Anna M; Sabater, Sergi; Barceló, Damià

    2014-01-15

    Chemical pollution is typically characterized by exposure to multiple rather than to single or a limited number of compounds. Parent compounds, transformation products and other non-targeted compounds yield mixtures whose composition can only be partially identified by monitoring, while a substantial proportion remains unknown. In this context, risk assessment based on the application of additive ecotoxicity models, such as concentration addition (CA), is rendered somewhat misleading. Here, we show that ecotoxicity risk information can be better understood upon consideration of the probabilistic distribution of risk among the different compounds. Toxic units of the compounds identified in a sample fit a lognormal probability distribution. The parameters characterizing this distribution (mean and standard deviation) provide information which can be tentatively interpreted as a measure of the toxic load and its apportionment among the constituents in the mixture (here interpreted as mixture complexity). Furthermore, they provide information for compound prioritization tailored to each site and enable prediction of some of the functional and structural biological variables associated with the receiving ecosystem. The proposed approach was tested in the Llobregat River basin (NE Spain) using exposure and toxicity data (algae and Daphnia) corresponding to 29 pharmaceuticals and 22 pesticides, and 5 structural and functional biological descriptors related to benthic macroinvertebrates (diversity, biomass) and biofilm metrics (diatom quality, chlorophyll-a content and photosynthetic capacity). Aggregated toxic units based on Daphnia and algae bioassays provided a good indication of the pollution pattern of the Llobregat River basin. Relative contribution of pesticides and pharmaceuticals to total toxic load was variable and highly site dependent, the latter group tending to increase its contribution in urban areas. Contaminated sites' toxic load was typically dominated by

  10. A two-flavor LOFF color superconductivity

    International Nuclear Information System (INIS)

    Sun Wei; Hou Defu

    2007-01-01

    Ever since the theory of color superconductivity was issued, it is likely to involve pairing between species of quarks with differing chemical potentials. For suitable values of the differences between chemical potentials, Cooper pairs with non-zero total momentum are favored, as was first realized by Larkin, Ovchinnikov, Fulde and Ferrell (LOFF). Condensates of this sort spontaneously break translational and rotational invariance, leading to gaps which vary periodically in a crystalline pattern. This article focuses on the two-flavor color superconducting phase at moderate baryon density. LOFF state is described through SU(2) NJL model. By using the mean-field approximation, N-G basis, fourier transformation, frequency summation, the thermodynamic potential and Gap equation are obtained. Finally, the window of LOFF state is found by the numerical method. (authors)

  11. Superconductivity transformers in power systems

    International Nuclear Information System (INIS)

    Martini, L.; Bocchi, M.; De Nigris, M.; Morandi, A.; Trevisan, L.; Fabbri, M.; Ribani, P.; Negrini, F.

    2008-01-01

    Transformers in superconducting materials at high temperatures offer many advantages in economic, environmental and functional aspects, compared to traditional transformers. Are presented the potentials of superconducting transformers available, aspects of design and the international state of the art [it

  12. Fullerides - Superconductivity at the limit

    NARCIS (Netherlands)

    Palstra, Thomas T. M.

    The successful synthesis of highly crystalline Cs3C60, exhibiting superconductivity up to a record temperature for fullerides of 38 K, demonstrates a powerful synthetic route for investigating the origin of superconductivity in this class of materials.

  13. Rf superconducting devices

    International Nuclear Information System (INIS)

    Hartwig, W.H.; Passow, C.

    1975-01-01

    Topics discussed include (1) the theory of superconductors in high-frequency fields (London surface impedance, anomalous normal surface resistance, pippard nonlocal theory, quantum mechanical model, superconductor parameters, quantum mechanical calculation techniques for the surface, impedance, and experimental verification of surface impedance theories); (2) residual resistance (separation of losses, magnetic field effects, surface resistance of imperfect and impure conductors, residual loss due to acoustic coupling, losses from nonideal surfaces, high magnetic field losses, field emission, and nonlinear effects); (3) design and performance of superconducting devices (design considerations, materials and fabrication techniques, measurement of performance, and frequency stability); (4) devices for particle acceleration and deflection (advantages and problems of using superconductors, accelerators for fast particles, accelerators for particles with slow velocities, beam optical devices separators, and applications and projects under way); (5) applications of low-power superconducting resonators (superconducting filters and tuners, oscillators and detectors, mixers and amplifiers, antennas and output tanks, superconducting resonators for materials research, and radiation detection with loaded superconducting resonators); and (6) transmission and delay lines

  14. Superconducting Ferromagnetic Nanodiamond.

    Science.gov (United States)

    Zhang, Gufei; Samuely, Tomas; Xu, Zheng; Jochum, Johanna K; Volodin, Alexander; Zhou, Shengqiang; May, Paul W; Onufriienko, Oleksandr; Kačmarčík, Jozef; Steele, Julian A; Li, Jun; Vanacken, Johan; Vacík, Jiri; Szabó, Pavol; Yuan, Haifeng; Roeffaers, Maarten B J; Cerbu, Dorin; Samuely, Peter; Hofkens, Johan; Moshchalkov, Victor V

    2017-06-27

    Superconductivity and ferromagnetism are two mutually antagonistic states in condensed matter. Research on the interplay between these two competing orderings sheds light not only on the cause of various quantum phenomena in strongly correlated systems but also on the general mechanism of superconductivity. Here we report on the observation of the electronic entanglement between superconducting and ferromagnetic states in hydrogenated boron-doped nanodiamond films, which have a superconducting transition temperature T c ∼ 3 K and a Curie temperature T Curie > 400 K. In spite of the high T Curie , our nanodiamond films demonstrate a decrease in the temperature dependence of magnetization below 100 K, in correspondence to an increase in the temperature dependence of resistivity. These anomalous magnetic and electrical transport properties reveal the presence of an intriguing precursor phase, in which spin fluctuations intervene as a result of the interplay between the two antagonistic states. Furthermore, the observations of high-temperature ferromagnetism, giant positive magnetoresistance, and anomalous Hall effect bring attention to the potential applications of our superconducting ferromagnetic nanodiamond films in magnetoelectronics, spintronics, and magnetic field sensing.

  15. Isolation, Chemical Fingerprinting and Simultaneous Quantification of Four Compounds from Tanacetum gracile Using a Validated HPLC–ESI-QTOF-Mass Spectrometry Method

    Science.gov (United States)

    Sharma, Neha; Kumar, Chetan; Dutt, Prabhu; Gupta, Suphla; Satti, Naresh K.; Chandra, Suresh; Kitchlu, Surinder; Paul, Satya; Vishwakarma, Ram A.; Verma, Mahendra K.

    2016-01-01

    The present study was conducted to carry out the phytochemical investigation of Tanacetum gracile Hook. f. & Thomson and to develop a method for the simultaneous quantification of the isolated compounds in the extracts of T. gracile growing in different locations. Cluster analysis rectangular similarity matrix was performed to understand the chemical fingerprinting variations in the extracts. High-performance liquid chromatography–electrospray ionization-quadrupole-time-of-flight-mass spectrometry (HPLC–ESI-QTOF-MS) was used to quantify four bioactive compounds, and separation of the compounds was achieved on a reverse-phase C8 column using a mobile phase of acetonitrile: 0.1% formic acid in water with a gradient elution by maintaining the flow rate of 300 μL/min. The QTOF–MS was operated using the electro-spray ionization technique with the positive ion polarity mode. The calibration curves of four marker compounds were linear over the concentration range of 3.12–100 ng/µL (R2> 0.996). A specific, accurate and precise HPLC–ESI-QTOF-MS method was optimized for the determination of kaempferol, ketoplenolide, tetramethoxyflavone and artemetin both individually and simultaneously. Quantification of these chemical markers in different extracts was carried out using this validated method. Kaempferol was isolated for the first time from T. gracile. PMID:26951542

  16. Isolation, Chemical Fingerprinting and Simultaneous Quantification of Four Compounds from Tanacetum gracile Using a Validated HPLC-ESI-QTOF-Mass Spectrometry Method.

    Science.gov (United States)

    Sharma, Neha; Kumar, Chetan; Dutt, Prabhu; Gupta, Suphla; Satti, Naresh K; Chandra, Suresh; Kitchlu, Surinder; Paul, Satya; Vishwakarma, Ram A; Verma, Mahendra K

    2016-01-01

    The present study was conducted to carry out the phytochemical investigation of Tanacetum gracile Hook. f. & Thomson and to develop a method for the simultaneous quantification of the isolated compounds in the extracts ofT. gracile growing in different locations. Cluster analysis rectangular similarity matrix was performed to understand the chemical fingerprinting variations in the extracts. High-performance liquid chromatography-electrospray ionization-quadrupole-time-of-flight-mass spectrometry (HPLC-ESI-QTOF-MS) was used to quantify four bioactive compounds, and separation of the compounds was achieved on a reverse-phase C8 column using a mobile phase of acetonitrile: 0.1% formic acid in water with a gradient elution by maintaining the flow rate of 300 μL/min. The QTOF-MS was operated using the electro-spray ionization technique with the positive ion polarity mode. The calibration curves of four marker compounds were linear over the concentration range of 3.12-100 ng/µL (R(2)> 0.996). A specific, accurate and precise HPLC-ESI-QTOF-MS method was optimized for the determination of kaempferol, ketoplenolide, tetramethoxyflavone and artemetin both individually and simultaneously. Quantification of these chemical markers in different extracts was carried out using this validated method. Kaempferol was isolated for the first time from T. gracile. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. The influence of ripening stage and region on the chemical compounds in mulberry fruits (Morus atropurpurea Roxb.) based on UPLC-QTOF-MS.

    Science.gov (United States)

    Yang, Jiufang; Wen, Haichao; Zhang, Lei; Zhang, Xiaoxu; Fu, Zheng; Li, Jingming

    2017-10-01

    Mulberries (Morus atropurpurea Roxb.) are rich in beneficial nutrients and secondary metabolites. Dramatic climate differences between western and eastern China lead to differences among the fruiting habits of mulberries grown in these regions. In this study, Xinjiang and Jiangsu, two regions in western and eastern China, respectively, were selected as sites where mulberry fruits (MFs) at different ripening stages were sampled. Their individual components, including both targeted and non-targeted chemical compounds, were detected by rapid ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Multivariate statistical analyses, including principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to compare MFs during ripening from these two regions. Potential biomarkers, which significantly contributed to the differentiation of the samples, were further identified or tentatively identified to determine the effects of ripening stages and regions on the chemical compounds in MFs. The results show that 43 compounds classified into nine different groups were identified in the MF samples from both the Xinjiang and Jiangsu regions. Among the compounds, all anthocyanins, carbohydrates and dihydroflavonols increased while phenolic acids and hydroxycoumarins decreased during ripening. Caffeoylquinic acids and some of anthocyanins could be regarded as important markers for MF ripening, and the accumulation of organic acids differentiated the samples from the two regions. Together, UPLC-QTOF-MS coupled with multivariate statistical analyses may be effective for metabolite profiling and identification of ripening degrees and cultivation regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Predicting chemically-induced skin reactions. Part I: QSAR models of skin sensitization and their application to identify potentially hazardous compounds

    International Nuclear Information System (INIS)

    Alves, Vinicius M.; Muratov, Eugene; Fourches, Denis; Strickland, Judy; Kleinstreuer, Nicole; Andrade, Carolina H.; Tropsha, Alexander

    2015-01-01

    Repetitive exposure to a chemical agent can induce an immune reaction in inherently susceptible individuals that leads to skin sensitization. Although many chemicals have been reported as skin sensitizers, there have been very few rigorously validated QSAR models with defined applicability domains (AD) that were developed using a large group of chemically diverse compounds. In this study, we have aimed to compile, curate, and integrate the largest publicly available dataset related to chemically-induced skin sensitization, use this data to generate rigorously validated and QSAR models for skin sensitization, and employ these models as a virtual screening tool for identifying putative sensitizers among environmental chemicals. We followed best practices for model building and validation implemented with our predictive QSAR workflow using Random Forest modeling technique in combination with SiRMS and Dragon descriptors. The Correct Classification Rate (CCR) for QSAR models discriminating sensitizers from non-sensitizers was 71–88% when evaluated on several external validation sets, within a broad AD, with positive (for sensitizers) and negative (for non-sensitizers) predicted rates of 85% and 79% respectively. When compared to the skin sensitization module included in the OECD QSAR Toolbox as well as to the skin sensitization model in publicly available VEGA software, our models showed a significantly higher prediction accuracy for the same sets of external compounds as evaluated by Positive Predicted Rate, Negative Predicted Rate, and CCR. These models were applied to identify putative chemical hazards in the Scorecard database of possible skin or sense organ toxicants as primary candidates for experimental validation. - Highlights: • It was compiled the largest publicly-available skin sensitization dataset. • Predictive QSAR models were developed for skin sensitization. • Developed models have higher prediction accuracy than OECD QSAR Toolbox. • Putative

  19. Superconductivity and ferromagnetism in nanomaterial NbSe2

    Science.gov (United States)

    Gill, Raminder

    2017-07-01

    Finding of superconductivity (SC) in ultra thin layer of Niobium diselenide (NbSe2) caught the attention of each condensed matter physicist in the era of nanotechnology. The coexistence of SC and magnetism have been a topic of interesting research in solid-state physics since the discovery of superconductivity. Ferromagnetism induced in any compound could destroy superconductivity by disturbing the cooper pairing of electrons of the atoms. The interplay between ferromagnetism (FM) and SC in nanomaterial NBSe2 impressed to study and to know the exact mechanism behind this coexistence which can lead to a very interesting research: superconductivity at room temperature. In this paper, I have theoretically studied the coexistence of SC and FM in NbSe2 and how this material could be useful in finding many high Tc nanomaterials.

  20. Superconductivity in Weyl semimetal candidate MoTe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Yanpeng; Naumov, Pavel; Rajamathi, Catherine; Barkalov, Oleg; Wu, Shu-Chun; Shekhar, Chandra; Sun, Yan; Suess, Vicky; Schmidt, Marcus; Schwarz, Ulrich; Schnelle, Walter; Felser, Claudia; Medvedev, Sergey [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany); Ali, Mazhar; Cava, Robert [Department of Chemistry, Princeton University, Princeton (United States); Hanfland, Michael [European Synchrotron Radiation Facility, Grenoble (France); Pippel, Eckhard; Werner, Peter; Hillebrand, Reinald; Parkin, Stuart [Max Planck Institute of Microstructure Physics, Halle (Germany); Foerster, Tobias; Kampert, Erik [Dresden High Magnetic Field Laboratory, Dresden (Germany); Yan, Binghai [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany); Max Planck Institute for the Physics of Complex Systems, Dresden (Germany)

    2016-07-01

    In this work, we investigate the sister compound of WTe{sub 2}, MoTe{sub 2}, which is also predicted to be a Weyl semimetal and a quantum spin Hall insulator in bulk and monolayer form, respectively. We find that MoTe{sub 2} exhibits superconductivity with a resistive transition temperature T{sub c} of 0.1 K. The application of a small pressure is shown to dramatically enhance the T{sub c}, with a maximum value of 8.2 K being obtained at 11.7 GPa (a more than 80-fold increase in Tc). This yields a dome-shaped superconducting phase diagram. Further explorations into the nature of the superconductivity in this system may provide insights into the interplay between superconductivity and topological physics.

  1. 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

  2. Superconductive analogue of spin glasses

    International Nuclear Information System (INIS)

    Feigel'man, M.; Ioffe, L.; Vinokur, V.; Larkin, A.

    1987-07-01

    The properties of granular superconductors in magnetic fields, namely the existence of a new superconductive state analogue of the low-temperature superconductive state in spin glasses are discussed in the frame of the infinite-range model and the finite-range models. Experiments for elucidation of spin-glass superconductive state in real systems are suggested. 30 refs

  3. Superconductive Signal-Processing Circuits

    Science.gov (United States)

    1994-08-01

    September 1991. 13. P. H. Xiao, E. Charbon , A. Sangiovanni-Vincentelli, T. Van Duzer,and S.W. Whiteley, "INDEX: An inductance extractor for superconducting...APPLIED SUPERCONDUCTIVITY, VOL. 3, ,Q I, MARCH 1993 2629 INDEX: An Inductance Extractor for Superconducting Circuits P. H. Xiao, E. Charbon , A

  4. Nonlinear terahertz superconducting plasmonics

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jingbo; Liang, Lanju; Jin, Biaobing, E-mail: bbjin@nju.edu.cn, E-mail: tonouchi@ile.osaka-u.ac.jp, E-mail: phwu@nju.edu.cn; Kang, Lin; Xu, Weiwei; Chen, Jian; Wu, Peiheng, E-mail: bbjin@nju.edu.cn, E-mail: tonouchi@ile.osaka-u.ac.jp, E-mail: phwu@nju.edu.cn [Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Zhang, Caihong; Kawayama, Iwao; Murakami, Hironaru; Tonouchi, Masayoshi, E-mail: bbjin@nju.edu.cn, E-mail: tonouchi@ile.osaka-u.ac.jp, E-mail: phwu@nju.edu.cn [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Wang, Huabing [Research Institute of Superconductor Electronics (RISE), School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); National Institute for Materials Science, Tsukuba 305-0047 (Japan)

    2014-10-20

    Nonlinear terahertz (THz) transmission through subwavelength hole array in superconducting niobium nitride (NbN) film is experimentally investigated using intense THz pulses. The good agreement between the measurement and numerical simulations indicates that the field strength dependent transmission mainly arises from the nonlinear properties of the superconducting film. Under weak THz pulses, the transmission peak can be tuned over a frequency range of 145 GHz which is attributed to the high kinetic inductance of 50 nm-thick NbN film. Utilizing the THz pump-THz probe spectroscopy, we study the dynamic process of transmission spectra and demonstrate that the transition time of such superconducting plasmonic device is within 5 ps.

  5. Applied Superconductivity Conference 2014

    CERN Document Server

    2015-01-01

    Energy Efficiency is a worldwide imperative driven by an increasing awareness of the need to conserve valuable natural resources. Superconductivity, the technology which revolutionized non-invasive medical imaging through MRI starting in the 1980’s, is one of the most promising enablers of energy efficiency in the 21st century. From energy efficient supercomputers to power generation, transmission, and storage, the spectrum of applications of superconductivity is broad in its reach and potential. As ASC comes to Charlotte, site of the hall of fame of NASCAR, our theme, “Race to Energy Efficiency,” is intended to inspire the world experts in superconductivity who will converge to Charlotte to present their latest results, exchange information, network, and plan and project the future breakthroughs.

  6. On anyon superconductivity--

    International Nuclear Information System (INIS)

    Chen, Y.-H.; Wilczek, F.; Witten, E.; Halperin, B.I.

    1989-01-01

    We investigate the statistical mechanics of a gas of fractional statistics particles in 2 + 1 dimensions. In the case of statistics very close to Fermi statistics (statistical parameter θ = π(1 - 1/n), for large n), the effect of the statistics is a weak attraction. Building upon earlier RPA calculation for the case n = 2, the authors argue that for large n perturbation theory is reliable and exhibits superfluidity (or superconductivity after coupling to electromagnetism). They describe the order parameter for this superconductng phase in terms of spontaneous breaking of commutativity of translations as opposed to the usual pairing order parameters. The vortices of the superconducting anyon gas are charged, and superconducting order parameters of the usual type vanish. They investigate the characteristic P and T violating phenomenology

  7. Connectivity and superconductivity

    CERN Document Server

    Rubinstein, Jacob

    2000-01-01

    The motto of connectivity and superconductivity is that the solutions of the Ginzburg--Landau equations are qualitatively influenced by the topology of the boundaries, as in multiply-connected samples. Special attention is paid to the "zero set", the set of the positions (also known as "quantum vortices") where the order parameter vanishes. The effects considered here usually become important in the regime where the coherence length is of the order of the dimensions of the sample. It takes the intuition of physicists and the awareness of mathematicians to find these new effects. In connectivity and superconductivity, theoretical and experimental physicists are brought together with pure and applied mathematicians to review these surprising results. This volume is intended to serve as a reference book for graduate students and researchers in physics or mathematics interested in superconductivity, or in the Schrödinger equation as a limiting case of the Ginzburg--Landau equations.

  8. Superconductivity for mass spectroscopy

    International Nuclear Information System (INIS)

    Ohkubo, Masataka

    2007-01-01

    Time-of-Flight Mass Spectroscopy (TOF-MS) with super-conducting detectors has two advantages over MS with conventional ion detectors. First, it is coverage for a very wide range of molecule weight over 1,000,000. Secondly, kinetic energies of accelerated molecules can be measured at impact events one by one. These unique features enable an ultimate detection efficiency of 100% for intact ions and a fragmentation analysis that is critical for top-down proteomics. Superconducting MS is expected to play a role in, for example, the detection of antigen-antibody complexes, which are important for medical diagnosis. In this paper, how superconductivity contributes to MS is described. (author)

  9. Superconducting super collider

    International Nuclear Information System (INIS)

    Limon, P.J.

    1987-01-01

    The Superconducting Super Collider is to be a 20 TeV per beam proton-proton accelerator and collider. Physically the SCC will be 52 miles in circumference and slightly oval in shape. The use of superconducting magnets instead of conventional cuts the circumference from 180 miles to the 52 miles. The operating cost of the SCC per year is estimated to be about $200-250 million. A detailed cost estimate of the project is roughly $3 billion in 1986 dollars. For the big collider ring, the technical cost are dominated by the magnet system. That is why one must focus on the cost and design of the magnets. Presently, the process of site selection is underway. The major R and D efforts concern superconducting dipoles. The magnets use niobium-titanium as a conductor stabilized in a copper matrix. 10 figures

  10. High-Tc Superconductors Based on FeAs Compounds

    CERN Document Server

    Izyumov, Yuri

    2010-01-01

    Physical properties and models of electronic structure are analyzed for a new class of high-TC superconductors which belong to iron-based layered compounds. Despite their variable chemical composition and differences in the crystal structure, these compounds possess similar physical characteristics, due to electron carriers in the FeAs layers and the interaction of these carriers with fluctuations of the magnetic order. A tremendous interest towards these materials is explained by the prospects of their practical use. In this monograph, a full picture of the formation of physical properties of these materials, in the context of existing theory models and electron structure studies, is given. The book is aimed at a broad circle of readers: physicists who study electronic properties of the FeAs compounds, chemists who synthesize them and specialists in the field of electronic structure calculations in solids. It is helpful not only to researchers active in the fields of superconductivity and magnetism, but also...

  11. Ultrahigh pressure superconductivity in molybdenum disulfide

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Zhenhua [Chinese Academy of Sciences (CAS), Hefei (China); Yen, Feihsiang [Chinese Academy of Sciences (CAS), Hefei (China); Peng, Feng [Luoyang Normal Univ., Luoyang (China); Zhu, Jinlong [Univ. of Nevada, Las Vegas, NV (United States); Zhang, Yijin [Univ. of Tokyo, Tokyo (Japan); Chen, Xuliang [Chinese Academy of Sciences (CAS), Hefei (China); Yang, Zhaorong [Chinese Academy of Sciences (CAS), Hefei (China); Nanjing Univ., Nanjing (China); Liu, Xiaodi [Chinese Academy of Sciences (CAS), Hefei (China); Ma, Yaming [Jilin Univ., Changchun (China); Zhao, Yusheng [Univ. of Nevada, Las Vegas, NV (United States); Kagayama, Tomoko [Osaka Univ., Osaka (Japan); Iwasa, Yoshihiro [Univ. of Tokyo, Tokyo (Japan); RIKEN Center for Emergent Matter Science (CEMS), Wako (Japan)

    2015-03-18

    Superconductivity commonly appears under pressure in charge densit wave (CDW)-bearing transition metal dichalcogenides (TMDs)1,2, but ha emerged so far only via either intercalation with electron donors3 or electrostati doping4 in CDW-free TMDs. Theoretical calculations have predicted that th latter should be metallized through bandgap closure under pressure5,6, bu superconductivity remained elusive in pristine 2H-MoS2 upon substantia compression, where a pressure of up to 60 GPa only evidenced the metalli state7,8. Here we report the emergence of superconductivity in pristine 2H-MoS at 90 GPa. The maximum onset transition temperature Tc(onset) of 11.5 K, th highest value among TMDs and nearly constant from 120 up to 200 GPa, is wel above that obtained by chemical doping3 but comparable to that obtained b electrostatic doping4. Tc(onset) is more than an order of magnitude larger tha present theoretical expectations, raising questions on either the curren calculation methodologies or the mechanism of the pressure-induced pairin state. Lastly, our findings strongly suggest further experimental and theoretical effort directed toward the study of the pressure-induced superconductivity in all CDWfre TMDs.

  12. Optical sensing method to analyze germination rate of Capsicum annum seeds treated with growth-promoting chemical compounds using optical coherence tomography

    Science.gov (United States)

    Wijesinghe, Ruchire Eranga; Lee, Seung-Yeol; Kim, Pilun; Jung, Hee-Young; Jeon, Mansik; Kim, Jeehyun

    2017-09-01

    Seed germination rate differs based on chemical treatments, and nondestructive measurements of germination rate have become an essential requirement in the field of agriculture. Seed scientists and other biologists are interested in optical sensing technologies-based biological discoveries due to nondestructive detection capability. Optical coherence tomography (OCT) has recently emerged as a powerful method for biological and plant material discoveries. We report an extended application of OCT by monitoring the germination rate acceleration of chemically primed seeds. To validate the versatility of the method, Capsicum annum seeds were primed using three chemical compounds: sterile distilled water (SDW), butandiol, and 1-hexadecene. Monitoring was performed using a 1310-nm swept source OCT system. The results confirmed more rapid morphological variations in the seeds treated with 1-hexadecene medium than the seeds treated with SDW and butandiol within 8 consecutive days. In addition, fresh weight measurements (gold standard) of seeds were monitored for 15 days, and the obtained results were correlated with the OCT results. Thus, such a method can be used in various agricultural fields, and OCT shows potential as a rigorous sensing method for selecting the optimal plant growth-promoting chemical compounds rapidly, when compared with the gold standard methods.

  13. Synthesis and evaluation of germanium organometallic compounds as precursors for chemical vapor deposition (CVD) and for obtaining nanoparticles of elemental germanium

    International Nuclear Information System (INIS)

    Ballestero Martinez, Ernesto

    2014-01-01

    The interest in the development of materials having applications such as electronics areas or biomarkers has affected the synthesis of new compounds based on germanium. This element has had two common oxidation states, +4 and +2, of them, +2 oxidation state has been the least studied and more reactive. Additionally, compounds of germanium (II) have had similarities with carbenes regarding the chemical acid-base Lewis. The preparation of compounds of germanium (II) with ligands β-decimations has enabled stabilization of new chemical functionalities and, simultaneously, provided interesting thermal properties to develop new preparation methodologies of materials with novel properties. The preparation of amides germanium(II) L'Ge(NHPh) [1, L' = {HC (CMeN-2,4,6-Me 3 C 6 H 2 ) 2 }], L'Ge(4-NHPy) [2] L'Ge(2-NHPy) [3] and LGe(2-NHPy) [4, L = {HC(CMeN-2,6- i Pr 2 C 6 H 3 ) 2 }]; the structural chemical composition were determined using techniques such as nuclear magnetic resonance ( 1 H, 13 C), other techniques are treated: elemental analysis, melting point, infrared spectroscopy, X-ray diffraction of single crystal and thermal gravimetric analysis (TGA). The TGA has showed that 4-1 have experimented a thermal decomposition; therefore, these compounds could be considered as potential starting materials for obtaining germanium nitride (GeN x ). Certainly, the availability of nitrogen coordinating atoms in the chemical composition in 2-4 have been interesting because it could act as ligands in reactions with transition metal complexes. That way, information could be obtained at the molecular level for some reactions and interactions that in surface chemistry have used similar link sites, for example, chemical functionalization of silicon and germanium substrates. The synthesis and structural characterization of germanium chloride compound(II) L''GeCl [5, L'' = HC{(CMe) (N-2,6-Me 2 C 6 H 3 )} 2 ], which could be used later for the

  14. Microscopic physical and chemical properties of graphite intercalation compounds. Final report, August 1, 1984--July 31, 1985

    Energy Technology Data Exchange (ETDEWEB)

    Eklund, P.C.

    1992-08-24

    Optical spectroscopy (Raman, FTIR and Reflection ) was used to study a variety of acceptor- and donor-type compounds synthesized to determine the microscopic models consistent with the spectrocsopic results. General finding is that the electrical conduction properties of these compounds can be understood on the basis that the intercalation of atomic and/or molecular species between the host graphite layers either raises or lowers the Fermi level (E{sub F)} in a graphitic band structure. This movement of E{sub F} is accomplished via a charge transfer of electrons from the intercalate layers to the graphitic layers (donor compounds), or vice versa (acceptor compounds). Furthermore, the band structure must be modified to take into account the layers of charge that occur as a result of the charge transfer. This charge layering introduces additional bands of states near E{sub F}, which are discussed. Charge-transfer also induces a perturbation of the graphitic normal mode frequencies which can be understood as the result of a contraction (acceptor compounds) or expansion (donor compounds) of the intralayer C-C bonds. Ab-initio calculations support this view and are in reasonable agreement with experimental data.

  15. Characterization of aromatic organosulfur model compounds relevant to fossil fuels by using atmospheric pressure chemical ionization with CS2 and high-resolution tandem mass spectrometry.

    Science.gov (United States)

    Tang, Weijuan; Sheng, Huaming; Jin, Chunfen; Riedeman, James S; Kenttämaa, Hilkka I

    2016-04-15

    The chemistry of desulfurization involved in processing crude oil is greatly dependent on the forms of sulfur in the oil. Sulfur exists in different chemical bonding environments in fossil fuels, including those in thiophenes and benzothiophenes, thiols, sulfides, and disulfides. In this study, the fragmentation behavior of the molecular ions of 17 aromatic organosulfur compounds with various functionalities was systematically investigated by using high-resolution tandem mass spectrometry. Multiple-stage tandem mass spectrometric experiments were carried out using a linear quadrupole ion trap (LQIT) equipped with an atmospheric pressure chemical ionization (APCI) source. (+)APCI/CS2 was used to generate stable dominant molecular ions for all the compounds studied except for three sulfides that also showed abundant fragment ions. The LQIT coupled with an orbitrap mass spectrometer was used for elemental composition analysis, which facilitated the identification of the neutral molecules lost during fragmentation. The characteristic fragment ions generated in MS(2) and MS(3) experiments provide clues for the chemical bonding environment of sulfur atoms in the examined compounds. Upon collision-induced dissociation (CID), the molecular ions can lose the sulfur atom in a variety of ways, including as S (32 Da), HS(•) (33 Da), H2 S (34 Da), CS (44 Da), (•) CHS (45 Da) and CH2 S (46 Da). These neutral fragments are not only indicative of the presence of sulfur, but also of the type of sulfur present in the compound. Generally, losses of HS(•) and H2 S were found to be associated with compounds containing saturated sulfur functionalities, while losses of S, CS and (•) CHS were more common for heteroaromatic sulfur compounds. High-resolution tandem mass spectrometry with APCI/CS2 ionization is a viable approach to determining the types of organosulfur compounds. It can potentially be applied to analysis of complex mixtures, which is beneficial to improving the

  16. High pressure induced superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Amaya, K.; Shimizu, K

    2003-10-15

    We have developed complex extreme condition of very low temperature down to 30 mK and ultra high pressure exceeding 200 GPa by assembling compact diamond anvil cell (DAC) on a powerful {sup 3}He/{sup 4}He dilution refrigerator. We have also developed measuring techniques of electrical resistance, magnetization and optical measurement for the sample confined in the sample space of the DAC. Using the newly developed apparatus and techniques, we have searched for superconductivity in various materials under pressure. In this paper, we will shortly review our newly developed experimental apparatus and techniques and discuss a few examples of pressure induced superconductivity which were observed recently.

  17. Today's markets for superconductivity

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    The worldwide market for superconductive products may exceed $1 billion in 1987. These products are expanding the frontiers of science, revolutionizing the art of medical diagnosis, and developing the energy technology of the future. In general, today's customers for superconductive equipment want the highest possible performance, almost regardless of cost. The products operate within a few degrees of absolute zero, and virtually all are fabricated from niobium or niobium alloys-so far the high-temperature superconductors discovered in 1986 and 1987 have had no impact on these markets. The industry shows potential and profound societal impact, even without the new materials

  18. Superconducting magnetic quadrupole

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.W.; Shepard, K.W.; Nolen, J.A.

    1995-08-01

    A design was developed for a 350 T/m, 2.6-cm clear aperture superconducting quadrupole focussing element for use in a very low q/m superconducting linac as discussed below. The quadrupole incorporates holmium pole tips, and a rectangular-section winding using standard commercially-available Nb-Ti wire. The magnet was modeled numerically using both 2D and 3D codes, as a basis for numerical ray tracing using the quadrupole as a linac element. Components for a prototype singlet are being procured during FY 1995.

  19. Superconducting cosmic strings

    International Nuclear Information System (INIS)

    Chudnovsky, E.M.; Field, G.B.; Spergel, D.N.; Vilenkin, A.

    1986-01-01

    Superconducting loops of string formed in the early Universe, if they are relatively light, can be an important source of relativistic particles in the Galaxy. They can be observed as sources of synchrotron radiation at centimeter wavelengths. We propose a string model for two recently discovered radio sources, the ''thread'' in the galactic center and the source G357.7-0.1, and predict that the filaments in these sources should move at relativistic speeds. We also consider superheavy superconducting strings, and the possibility that they be observed as extragalactic radio sources

  20. Gambling with Superconducting Fluctuations

    Science.gov (United States)

    Foltyn, Marek; Zgirski, Maciej

    2015-08-01

    Josephson junctions and superconducting nanowires, when biased close to superconducting critical current, can switch to a nonzero voltage state by thermal or quantum fluctuations. The process is understood as an escape of a Brownian particle from a metastable state. Since this effect is fully stochastic, we propose to use it for generating random numbers. We present protocol for obtaining random numbers and test the experimentally harvested data for their fidelity. Our work is prerequisite for using the Josephson junction as a tool for stochastic (probabilistic) determination of physical parameters such as magnetic flux, temperature, and current.