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Sample records for cryst d65 148-155

  1. Comment on "Experimental study of the orientation dependence of indium incorporation in GaInN" [J. Cryst. Growth 433 (2016) 7-12

    Science.gov (United States)

    Monavarian, Morteza

    2016-07-01

    The authors of the title paper (J. Cryst. Growth 433 (2016) 7-12) reported on experimental comparison of indium incorporation efficiency in wide variety of orientations tilted from the basal plane toward a-plane (a-family planes) or m-plane (m-family planes) and some mixed planes. Despite a good investigation and useful information reported in this manuscript, some points of criticism, concerning the inclination angle calculations, optical characterizations of the layers, and the final conclusions are highlighted in this comment to consider.

  2. 1,1'-(Diselanediylbis{[P,P-diphenyl-N-(tri-methyl-sil-yl)phospho-rimido-yl]methanylyl-idene})bis-[1,1-diphenyl-N-(tri-methyl-sil-yl)-λ(5)-phosphanamine] pentane disolvate.

    Science.gov (United States)

    Thirumoorthi, Ramalingam; Chivers, Tristram; Laitinen, Risto S

    2014-01-01

    The title compound, C62H78N4P4Se2Si4·2C5H12, is made up of two [SeC(PPh2NSiMe3)(PPh2NHSiMe3)] units related by an inversion center situated at the mid-point of the diselenide bond. It crystallized with two disordered mol-ecules of pentane used as solvent of crystallization. It is a rare example of an anti-periplanar diselenide and exhibits a long Se-Se bond of 2.4717 (8) Å. The Se-C bond length of 1.876 (5) Å is short in comparison with the range of values found for other diselenides (1.91-1.97 Å). The mol-ecule exhibits two intra-molecular N-H⋯N hydrogen bonds. In the crystal, there are no significant inter-molecular inter-actions present. One of the Me3Si- groups is disordered over two positions with a refined occupancy ratio of 0.708 (8):0.292 (8). The contribution of the disordered solvent to the scattering was removed with the SQUEEZE option of PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155]. The solvent contribution has been included in the reported mol-ecular weight and density.

  3. Crystal structure of 5-amino-5'-chloro-6-(4-chloro-benzo-yl)-8-nitro-2,3-di-hydro-1H-spiro-[imidazo[1,2-a]pyridine-7,3'-indolin]-2'-one including an unknown solvent mol-ecule.

    Science.gov (United States)

    Nagalakshmi, R A; Suresh, J; Sivakumar, S; Kumar, R Ranjith; Lakshman, P L Nilantha

    2014-09-01

    The asymmetric unit of the title compound, C21H15Cl2N5O4, contains two independent mol-ecules (A and B) having similar conformations. The amine (NH2) group forms an intra-molecular hydrogen bond with the benzoyl group, giving an S(6) ring motif in both mol-ecules. The central six-membered rings adopt sofa conformations and the imidazole rings are planar (r.m.s deviations = 0.0150 and 0.0166 Å). The pyridine and imidazole rings are inclined to one another by 3.54 (1) and 3.03 (1)° in mol-ecules A and B, respectively. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds, forming chains along the a axis which enclose R 2 (2)(16) ring motifs. The rings are linked by weak N-H⋯O and C-H⋯O hydrogen bonds and C-H⋯π inter-actions forming sheets lying parallel to (001). A region of disordered electron density, most probably disordered solvent mol-ecules, occupying voids of ca 753 Å(3) for an electron count of 260, was treated using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155]. Their formula mass and unit-cell characteristics were not taken into account during refinement.

  4. 2-Vinylpyridine–tris(pentafluorophenylborane hexane monosolvate

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    Marcus Klahn

    2012-04-01

    Full Text Available The title compound, C7H7N·B(C6F53·C6H14, was obtained by the stoichiometric reaction of 2-vinylpyridine and tris(pentafluorophenylborane in toluene. The formed adduct exhibits a restricted rotation along the B—N bond resulting in an asymmetry, which can be also observed in the 19F NMR spectra. The B—N distance is equivalent to the distances found for 2-methylpyridine and 2-ethylpyridine B(C6F53 adducts. For the final refinement, the contributions of disordered solvent molecules were removed from the diffraction data with SQUEEZE in PLATON [van der Sluis & Spek (1990. Acta Cryst. A46, 194–201; Spek (2009. Acta Cryst. D65, 148–155].

  5. The Ste locus, a component of the parasitic cry-Ste system of Drosophila melanogaster, encodes a protein that forms crystals in primary spermatocytes and mimics properties of the beta subunit of casein kinase 2

    DEFF Research Database (Denmark)

    Bozzetti, M P; Massari, S; Finelli, P

    1995-01-01

    . To understand how the derepression of the Stellate elements gives rise to these abnormalities, we have expressed the protein encoded by the Stellate sequences in bacteria and produced an antibody against the fusion protein. Immunostaining of crystal- testes has clearly shown that the Stellate protein is a major...

  6. The Ste locus, a component of the parasitic cry-Ste system of Drosophila melanogaster, encodes a protein that forms crystals in primary spermatocytes and mimics properties of the beta subunit of casein kinase 2

    DEFF Research Database (Denmark)

    Bozzetti, M P; Massari, S; Finelli, P

    1995-01-01

    Males of Drosophila melanogaster lacking the Y chromosome-linked crystal locus show multiple meiotic alterations including chromosome disorganization and prominent crystal formation in primary spermatocytes. These alterations are due to the derepression of the X chromosome-linked Stellate sequenc...

  7. 1-[2,2-Bis(1,3-benzimidazol-1-ylmethyl-3-bromopropyl]-1,3-benzimidazole

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    Tai-Bao Wei

    2011-07-01

    Full Text Available The title compound, C26H23BrN6, has been synthesized as a potential ligand for the construction of metal–organic frameworks. The three benzimidazolyl groups present three potential coordination nodes. The dihedral angles between the benzimidazole ring systems are 74.03 (10, 66.49 (9 and 74.09 (9°. The structure contains large voids, which contain highly disordered solvent molecules that may be CH3CH2OH. Since the solvent molecules could not be located, the PLATON/SQUEEZE procedure [Spek (2009. Acta Cryst. D65, 148–155] was used.

  8. Abacavir methanol 2.5-solvate

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    Phuong-Truc T. Pham

    2009-08-01

    Full Text Available The structure of abacavir (systematic name: {(1S,4R-4-[2-amino-6-(cyclopropylamino-9H-purin-9-yl]cyclopent-2-en-1-yl}methanol, C14H18N6O·2.5CH3OH, consists of hydrogen-bonded ribbons which are further held together by additional hydrogen bonds involving the hydroxyl group and two N atoms on an adjacent purine. The asymmetric unit also contains 2.5 molecules of methanol solvate which were grossly disordered and were excluded using SQUEEZE subroutine in PLATON [Spek, (2009. Acta Cryst. D65, 148–155].

  9. Bis{μ-cis-1,3-bis[(di-tert-butylphosphanyloxy]cyclohexane-κ2P:P′}bis[carbonylnickel(0] including an unknown solvent molecule

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    Klara J. Jonasson

    2014-05-01

    Full Text Available The title compound, [Ni2(C22H46P2O22(CO2], is located about a centre of inversion with the Ni0 atom within a distorted trigonal–planar geometry. The cyclohexyl rings are in the usual chair conformation with the 1,3-cis substituents equatorially oriented. No specific intermolecular interactions are noted in the crystal packing. A region of disordered electron density, most probably a disordered deuterobenzene solvent molecule, was treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155]. Its formula mass and unit-cell characteristics were not taken into account during refinement.

  10. 2-(5-Iodo-2-oxoindolin-3-ylidenehydrazinecarbothioamide including an unknown solvate

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    Viviane Conceição Duarte de Bittencourt

    2014-06-01

    Full Text Available The molecule of the title compound, C9H7IN4OS, is almost planar (r.m.s. deviation = 0.0373 Å. In the molecule, N—H...N and N—H...O hydrogen bonds generate, respectively, S(5 and S(6 ring motifs. In the crystal, molecules are linked via N—H...O hydrogen bonds, forming chains propagating along [010]. These chains are linked via S...I contacts [3.4915 (16 Å], forming sheets lying parallel to (100. A region of disordered electron density, probably a disordered tetrahydrofuran solvent molecule, was treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155]. The formula mass and unit-cell characteristics were not taken into account during refinement.

  11. 1,3,5-Tri-p-tolylpentane-1,5-diol

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    A. Thiruvalluvar

    2014-02-01

    Full Text Available In the title compound, C26H30O2, the central benzene ring forms dihedral angles of 14.85 (15 and 28.17 (14° with the terminal benzene rings. The dihedral angle between the terminal benzene rings is 32.14 (13°. The crystal packing exhibits two strong intermolecular O—H...O hydrogen bonds, forming directed four-membered co-operative rings. A region of disordered electron density, most probably disordered ethyl acetate solvent molecules, occupying voids of ca 519 Å3 for an electron count of 59, was treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155]. Their formula mass and unit-cell characteristics were not taken into account during refinement. The structure was refined as an inversion twin [absolute structure parameter = −0.3 (4].

  12. 3,10,14,21-Tetrakis(4-methoxyphenylpentacyclo[11.8.0.02,11.04,9.015,20]henicosa-1(21,2,4(9,5,7,10,13,15(20,16,18-decaen-12-one chloroform monosolvate

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    S. Gopinath

    2014-08-01

    Full Text Available The asymmetric unit of the title compound, C49H36O6·CHCl3, contains half an organic molecule, the complete molecule being generated by the operation of a crystallographic twofold rotation axis, and half a highly disordered chloroform molecule. The contribution to the diffraction pattern of the latter was removed using the program SQUEEZE in PLATON [Spek (2009. Acta Cryst. D65, 148–155]; the unit-cell characteristics take into account the presence of CHCl3. The dihedral angles between the planes of the naphthalene ring system and the methoxybenzene rings are 71.05 (7 (syn to the central C=O group and 57.27 (6° (anti to the central C=O group. In the crystal, molecules are linked by C—H...O interactions, generating C(12 chains running parallel to the b axis.

  13. 2-(2-Chlorophenyl-N-cyclohexyl-2-oxoacetamide

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    Xiu-Dan Jin

    2013-04-01

    Full Text Available In the title compound, C14H16ClNO2, the cyclohexyl ring has a chair conformation. The dihedral angle between the benzene ring and the mean plane of the four planar C atoms of the cyclohexyl ring is 45.2 (3°. The two carbonyl groups are trans to one another, with an O=C—C=O torsion angle of −137.1 (3°. In the crystal, molecules are linked by N—H...O hydrogen bonds forming chains propagating along [001]. A region of disordered electron density, situated near the unit-cell corners, was treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155]. It gave a solvent-accessible void of ca 400 Å3 for only 21 electrons. It is probably due to traces of the solvent of crystallization and was not taken into account during structure refinement.

  14. 5′′-(4-Nitrobenzylidene-7′-(4-nitrophenyl-1′′-methyl-1′,3′,5′,6′,7′,7a′-hexahydrodispiro[acenaphthylene-1,5′-pyrrolo[1,2-c][1,3]thiazole-6′,3′′-piperidine]-2,4′′(1H-dione including an unknown solvate

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    P. L. Nilantha Lakshman

    2013-08-01

    Full Text Available The title compound, C35H28N4O6S, crystallizes with two molecules in the asymmetric unit. In both molecules, the piperidine ring adopts a shallow-chair conformation, the thiazole ring adopts a twisted conformation about the Cm—N bond (m = methine and the pyrrole ring adopts an envelope conformation with the C atom shared with the thiazole ring as the flap. In the crystal, inversion dimers linked by pairs of C—H...O interactions generate R22(34 loops for one of the asymmetric molecules. Further C—H...O links also involving the other molecule lead to a three-dimesional network. The contribution of the highly disordered solvent to the scattering was removed with SQUEEZE option of PLATON [Spek (2009. Acta Cryst. D65, 148–155]. The solvent contribution is not included in the reported molecular weight and density.

  15. Carbonyl{3,3′-di-tert-butyl-5,5′-dimethoxy-2,2′-bis[(4,4,5,5-tetramethyl-1,3,2-dioxaphospholan-2-yloxy]biphenyl-κ2P,P′}hydrido(triphenylphosphane-κPrhodium(I diethyl ether trisolvate

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    Detlef Selent

    2013-01-01

    Full Text Available In the title compound, [RhH(C74H68O8P2(C18H15P(CO]·3C4H10O, the CHP3 coordination set at the RhI ion is arranged in a distorted trigonal–bipyramidal geometry with the P atoms adopting equatorial coordination sites and the C atom of the carbonyl ligand as well as the H atom adopting the axial sites. The asymmetric unit contains two very similar molecules of the rhodium complex, two half-occupied diethyl ether molecules and further diethyl ether solvent molecules which could not be modelled successfully. Therefore contributions of the latter were removed from the diffraction data using the SQUEEZE procedure in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  16. 1-Decyl-6-nitro-1H-benzimidazol-2(3H-one

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    Younes Ouzidan

    2011-11-01

    Full Text Available The title molecule, C17H25N3O3, is built up from fused six- and five-membered rings linked to a –C10H21 chain. The fused-ring system is essentially planar, the largest deviation from the mean plane being 0.009 (2 Å. The chain is roughly perpendicular to this plane, making a dihedral angle of 79.5 (2°. In the crystal, N—H...O hydrogen bonds build infinite chains along [010]. There are channels in the structure containing disordered hexane. The contribution of this solvent to the scattering power was suppressed using the SQUEEZE option in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  17. 5-Methylspiro[indoline-3,7′-[6H,7H,8H]pyrano[3,2-c:5,6-c′]di[1]benzopyran]-2,6′,8′-trione chloroform hemisolvate

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    Abdulrahman I. Almansour

    2012-04-01

    Full Text Available In the title compound, C27H15NO6·0.5CHCl3, the central pyran ring and both the benzopyran systems are planar, with the dihedral angle between the outer rings being 3.24 (6°. The indolin-2-one system is in a perpendicular configuration with respect to the pyran ring [dihedral angle = 87.58 (2°]. Supramolecular layers in the ac plane are formed in the crystal structure whereby inversion-related molecules are connected by N—H...O hydrogen bonds. These are further linked by C—H...O interactions, forming a supramolecular layer in the ac plane. Disordered CHCl3 solvent in the structure was modelled with the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  18. (R-2-[(Dimethylaminomethyl]-1,1′-bis(diphenylphosphinothioylferrocene dichloromethane monsolvate

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    Elisabeth Philippe

    2012-06-01

    Full Text Available In the title compound, [Fe(C20H21NPS(C17H14PS]·CH2Cl2, both cyclopentadienyl (Cp rings constituting the ferrocene unit are substituted by a sulfur-protected diphenylphosphine. One of the Cp ligands is additionally substituted by a dimethylaminomethyl group causing the chirality of the molecule. Surprisingly, although the synthetic procedure yielded the title compound as a racemic mixture, the reported crystal is enantiomerically pure with the R absolute configuration. The dimethylamino group is exo with respect to the Cp ring. Both diphenylthiophosphine groups are trans with respect to the centroid–Fe–centroid direction. Weak intramolecular C—H...S and C—H...π interactions between symmetry-related molecules are observed. The contribution of the disordered solvent was removed from the refinement using SQUEEZE in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  19. Bis{2-[(Triphenylmethylamino]phenyl} diselenide acetonitrile monosolvate

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    Adam Neuba

    2014-05-01

    Full Text Available The molecular structure of the title compound, C50H40N2Se2·C2H3N, shows a syn conformation of the benzene rings bound to the Se atoms, with an Se—Se bond length of 2.3529 (6 Å and a C—Se—Se—C torsion angle of 93.53 (14°. The two Se-bonded aromatic ring planes make a dihedral angle of 18.42 (16°. Intramolecular N—H...Se hydrogen bonds are noted. Intermolecular C—H...Se interactions give rise to supramolecular chains extended along [100]. One severely disordered acetonitrile solvent molecule per asymmetric unit was treated with SQUEEZE in PLATON [Spek (2009. Acta Cryst. D65, 148–155]; the crystal data take the presence of this molecule into account.

  20. 1,3,5-Tri-p-tolyl­pentane-1,5-diol

    Science.gov (United States)

    Thiruvalluvar, A.; Chithiravel, R.; Muthusubramanian, S.; Butcher, R. J.

    2014-01-01

    In the title compound, C26H30O2, the central benzene ring forms dihedral angles of 14.85 (15) and 28.17 (14)° with the terminal benzene rings. The dihedral angle between the terminal benzene rings is 32.14 (13)°. The crystal packing exhibits two strong inter­molecular O—H⋯O hydrogen bonds, forming directed four-membered co-operative rings. A region of disordered electron density, most probably disordered ethyl acetate solvent mol­ecules, occupying voids of ca 519 Å3 for an electron count of 59, was treated using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]. Their formula mass and unit-cell characteristics were not taken into account during refinement. The structure was refined as an inversion twin [absolute structure parameter = −0.3 (4)]. PMID:24764851

  1. 2-(5-Iodo-2-oxoindolin-3-yl­idene)hydrazinecarbo­thio­amide including an unknown solvate

    Science.gov (United States)

    Conceição Duarte de Bittencourt, Viviane; Carratu Gervini, Vanessa; Rosa de Menezes Vicenti, Juliano; Maciel Velasques, Jecika; Jussiane Zambiazi, Priscilla

    2014-01-01

    The mol­ecule of the title compound, C9H7IN4OS, is almost planar (r.m.s. deviation = 0.0373 Å). In the mol­ecule, N—H⋯N and N—H⋯O hydrogen bonds generate, respectively, S(5) and S(6) ring motifs. In the crystal, mol­ecules are linked via N—H⋯O hydrogen bonds, forming chains propagating along [010]. These chains are linked via S⋯I contacts [3.4915 (16) Å], forming sheets lying parallel to (100). A region of disordered electron density, probably a disordered tetra­hydro­furan solvent mol­ecule, was treated using the SQUEEZE routine in PLATON [Spek (2009). Acta Cryst. D65, 148–155]. The formula mass and unit-cell characteristics were not taken into account during refinement. PMID:24940248

  2. (1,6,7,12-Tetraazaperylene-κ2N,N′bis(4,4′,5,5′-tetramethyl-2,2′-bipyridyl-κ2N,N′ruthenium(II bis(hexafluoridophosphate acetonitrile trisolvate

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    Thomas Brietzke

    2014-06-01

    Full Text Available In the title compound, rac-[Ru(C14H16N22(C16H8N4](PF62·3C2H3N, discrete dimers of complex cations, [Ru(tmbpy2tape]2+, of opposite chirality are formed (tmbpy = tetramethylbipyridine; tape = tetraazaperylene, held together by π–π stacking interactions between the tetraazaperylene moieties with centroid–centroid distances in the range 3.563 (3–3.837 (3 Å. These interactions exhibit a parallel displaced π–π stacking mode. Additional weak C—H...π-ring and C—H...N and C—H...F interactions are found, leading to a three-dimensional architecture. The RuII atom is coordinated in a distorted octahedral geometry. The counter-charge is provided by two hexafluoridophosphate anions and the asymmetric unit is completed by three acetonitrile solvent molecules of crystallization. Four F atoms of one PF6− anion are disordered over three sets of sites with occupancies of 0.517 (3:0.244 (3:0.239 (3. Two acetonitrile solvent molecules are highly disordered and their estimated scattering contribution was subtracted from the observed diffraction data using the SQUEEZE option in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  3. Tetrakis(μ3-2-{[1,1-bis(hydroxymethyl-2-oxidoethyl]iminomethyl}-6-nitrophenolatotetracopper(II

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    Eduard N. Chygorin

    2014-02-01

    Full Text Available The title cluster, [Cu4(C11H12N2O64], was obtained from the Cu0–FeCl2·4H2O–H4L–Et3N–DMF reaction system (in air, where H4L is 2-hydroxymethyl-2{[(2-hydroxy-3-nitrophenylmethylidene]amino}propane-1,3-diol and DMF is dimethylformamide. The asymmetric unit consists of one Cu2+ ion and one dianionic ligand; a -4 symmetry element generates the cluster, which contains a {Cu4O4} cubane-like core. The metal ion has an elongated square-based pyramidal CuNO4 coordination geometry with the N atom in a basal site. An intramolecular O—H...O hydrogen bond is observed. The solvent molecules were found to be highly disordered and their contribution to the scattering was removed with the SQUEEZE procedure in PLATON [Spek (2009. Acta Cryst. D65, 148–155], which indicated a solvent cavity of volume 3131 Å3 containing approximately 749 electrons. These solvent molecules are not considered in the given chemical formula.

  4. (Acetonitrile{2-[bis(pyridin-2-ylmethyl-κ2Namino-κN]-N-(2,6-dimethylphenylacetamide-κO}(perchlorato-κOzinc (acetonitrile{2-[bis(pyridin-2-ylmethyl-κ2Namino-κN]-N-(2,6-dimethylphenylacetamide-κO}zinc tris(perchlorate

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    Ove Alexander Høgmoen Åstrand

    2013-02-01

    Full Text Available In the title salt, [Zn(C22H24N4O(CH3CN][Zn(ClO4(C22H24N4O(CH3CN](ClO43, two differently coordinated zinc cations occur. In the first complex, the metal ion is coordinated by the N,N′,N′′,O-tetradentate acetamide ligand and an acetonitrile N atom, generating an approximate trigonal–bipyramidal coordination geometry, with the O atom in an equatorial site and the acetonitrile N atom in an axial site. In the second complex ion, a perchlorate ion is also bonded to the zinc ion, generating a distorted trans-ZnO2N4 octahedron. Of the uncoordinating perchlorate ions, one lies on a crystallographic twofold axis and one lies close to a twofold axis and has a site occupancy of 0.5. N—H...O and N—H...(O,O hydrogen bonds are observed in the crystal. Disordered solvent molecules occupy about 11% of the unit-cell volume; their contribution to the scattering was removed with the SQUEEZE routine of the PLATON program [Spek (2009. Acta Cryst. D65, 148–155.].

  5. Chlorido(pyridine-κN(5,10,15,20-tetraphenylporphyrinato-κ4Ncobalt(III chloroform hemisolvate

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    Yassin Belghith

    2012-08-01

    Full Text Available In the title complex, [CoCl(C44H28N4(C5H5N]·0.5CHCl3 or [CoIII(TPPCl(py]·0.5CHCl3 (where TPP is the dianion of tetraphenylporphyrin and py is pyridine, the average equatorial cobalt–pyrrole N atom bond length (Co—Np is 1.958 (7 Å and the axial Co—Cl and Co—Npy distances are 2.2339 (6 and 1.9898 (17 Å, respectively. The tetraphenylporphyrinate dianion exhibits an important nonplanar conformation with major ruffling and saddling distortions. In the crystal, molecules are linked via weak C—H...π interactions. In the difference Fourier map, a region of highly disordered electron density was estimated using the SQUEEZE routine [PLATON; Spek (2009, Acta Cryst. D65, 148–155] to be equivalent to one half-molecule of CHCl3 per molecule of the complex.

  6. (E-1-Phenylethanone semicarbazone

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    Hoong-Kun Fun

    2009-08-01

    Full Text Available In the title compound, C9H11N3O, the benzene ring is disordered over two positions with refined occupancies of 0.922 (5 and 0.078 (5. The program PLATON [Spek (2009. Acta Cryst. D65, 148–155] recommends the solution in the space group C2/m with a = 7.3050 (3, b = 6.6745 (2, c = 18.3853 (6 Å and β = 96.986 (2°. However, the large number of non-extinct reflections needed to be ignored if C2/m is chosen suggested that the space group is incorrect, even though the R values are lower than that for P21/c. The semicarbazone group is essentially planar, with a maximum deviation of 0.046 (1 Å for one of the N atoms. The mean plane of the semicarbazone group forms dihedral angles of 33.61 (8 and 39.1 (9° with the benzene ring of the major and minor components, respectively. In the crystal structure, molecules are linked by intermolecular N—H...O hydrogen bonds into extended chains along the c axis. The crystal structure is further stabilized by weak intermolucular C—H...π interactions.

  7. catena-Poly[[[iodidocopper(I]-{μ-N-[(pyridin-2-yl-κNmethylidene]pyridin-3-amine-κ2N3:N1}] acetonitrile hemisolvate

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    Ali Mahmoudi

    2012-10-01

    Full Text Available In the asymmetric unit of the title polymeric complex, {[CuI(C11H9N3]·0.5CH3CN}n, there are two CuI atoms, two N-[(pyridin-2-yl-κNmethylidene]pyridin-3-amine (PyPy ligands and two I atoms. Both CuI atoms have a distorted tetrahedral geometry, each being coordinated by one I atom, two N atoms of one PyPy ligand and one N atom from an adjacent PyPy ligand. In the crystal, infinite helical chains of [Cu2(PyPy2]n are formed propagating along the b axis. These chains are linked via weak C—H...I hydrogen bonds and π–π stacking interactions [shortest centroid–centroid distance = 3.2727 (14 Å]. During the refinement, electron-density peaks were located that were believed to be highly disordered solvent molecules (possibly acetonitrile. The SQUEEZE option in PLATON [Spek (2009. Acta Cryst. D65, 148–155] indicated there were solvent cavities with a total volume of 196 Å3 containing approximately 60 electrons per unit cell, which equated to one molecule of acetonitrile per asymmetric unit.

  8. Poly[dimethylammonium [(μ2-benzene-1,2-dicarboxylato-κ2O1:O3[μ2-3-(pyridin-4-yl-1H-pyrazol-1-ido-κ2N1:N3]cuprate(II

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    Liu Na

    2013-07-01

    Full Text Available In the title complex, {(C2H8N[Cu(C8H4O4(C8H6N3]}n, there are two CuII cations (each located on a centre of inversion, one benzene-1,2-dicarboxylate dianion, one 3-(pyridin-4-yl-1H-pyrazol-1-ide anion and one dimethylammonium cation in the asymmetric unit. The dimethylammonium cation was highly disordered and was treated with the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155]; the crystallographic data takes into account the presence of the cation. Each CuII cation exhibits a square-planar coordination geometry. A benzene-1,2-dicarboxylate dianion bridges two CuII cations, building a linear chain along [001]. The chains are connected by 3-(pyridin-4-yl-1H-pyrazol-1-ide anions, constructing a layer parallel to (101. The layers are assembled into a three-dimensional supramolecular network through C—H...π interactions.

  9. 5,10,15,20-Tetrakis(4-acetyloxyphenylporphyrin including an unknown solvate

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    Micael D. Miranda

    2012-12-01

    Full Text Available Molecules of the title compound, C52H38N4O8, are located on an inversion center so that the asymmetric cell contains one half of the molecule. The macrocycle exhibits a ruffled conformation with a maximum deviation of 0.16 Å for the 24 macrocycle atoms: the dihedral angle between adjacent five-membered rings is 5.13 (19°. The benzene rings are rotated by 70.25 (19° with respect to their adjacent protonated five-membered rings, and by 65.56 (19° with respect to the unprotonated rings. The porphyrin conformation is supported by bifurcated N—H...(N,N hydrogen bonds. The structure contained poorly resolved solvent molecules in voids of volume 217 Å3 per unit cell. The latter were treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155]. As the solvent could not be identified exactly, it was not included in the calculation of the overall formula weight, density and absorption coefficient.

  10. (η6-Benzene(carbonato-κ2O,O′[dicyclohexyl(naphthalen-1-ylmethylphosphane-κP]ruthenium(II chloroform trisolvate

    Directory of Open Access Journals (Sweden)

    Saravanan Gowrisankar

    2014-07-01

    Full Text Available The title compound, [Ru(CO3(η6-C6H6{(C6H112P(CH2C10H7}]·3CHCl3, was synthesized by carbonation of [RuCl2(η6-C6H6{(C6H112P(CH2C10H7}] with NaHCO3 in methanol at room temperature. The RuII atom is surrounded by a benzene ligand, a chelating carbonate group and a phosphane ligand in a piano-stool configuration. The crystal packing is consolidated by C—H...O and C—H...Cl hydrogen-bonding interactions between adjacent metal complexes and between the complexes and the solvent molecules. The asymmetric unit contains one metal complex and three chloroform solvent molecules of which only one was modelled. The estimated diffraction contributions of the other two strongly disordered chloroform solvent molecules were substracted from the observed diffraction data using the SQUEEZE procedure in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  11. Aqua(μ-cone-26,28-dibutoxy-25,27-bis{N-[5-(dimethylaminonaphthalene-1-sulfonyl]carbamoylmethoxy}-5,11,17,23-tetrakis(1,1-dimethylethylcalix[4]arene(2−disodium acetonitrile tetrasolvate

    Directory of Open Access Journals (Sweden)

    Pogisego Dinake

    2012-04-01

    Full Text Available The structure of the title complex, [Na2(C80H98N4O10S2(H2O]·4CH3CN, obtained after crystallization from acetonitrile, contains two formula units in the asymmetric unit (Z′ = 2 and an estimated four molecules of acetonitrile per calixarene moiety. It is unusual for two Na+ ions to occupy the lower rims of the cone calix[4]arene, as in this case, with one Na+ ion forming two O→ Na+ coordinate bonds with the two butoxy groups and four such bonds with the two N-dansyl carboxamide groups, forming six dative bonds between Na+ and O. On the other hand, the other Na+ ion forms only five O→Na+ coordinate bonds on the far end of the calix[4]arene lower rim, bringing the two dansyl groups in close proximity with each other. There also appears to be an O→Na+ coordination coming from a dangling water molecule. The structure contained both resolved and poorly resolved solvent molecules. The latter were treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  12. Bis(2-amino-1,3-benzothiazole-κN3dichloridozinc(II ethanol hemisolvate

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    Young-Inn Kim

    2012-02-01

    Full Text Available In the title compound, [ZnCl2(C7H6N2S2]·0.5CH3CH2OH, the ZnII atom is coordinated by two N atoms of two 2-aminobenzothiazole ligands and two Cl atoms within a distorted tetrahedral geometry. The dihedral angle between the N/Zn/N and Cl/Zn/Cl planes is 86.22 (7°. The benzothiazole molecules are almost perpendicular to each other, forming a dihedral angle of 80.20 (8°. The molecular structure is stabilized by intramolecular N—H...Cl hydrogen bonds. In the crystal, intermolecular N—H...Cl hydrogen bonds link the molecules into a three-dimensional network. The SQUEEZE procedure in PLATON [Spek (2009. Acta Cryst. D65, 148–155] was used to model a disordered ethanol solvent molecule; the calculated unit-cell data allow for the presence of half of this molecule in the asymmetric unit.

  13. 4-(4-Bromophenyl-7,7-dimethyl-2-methylamino-3-nitro-7,8-dihydro-4H-chromen-5(6H-one including an unknown solvate

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    S. Antony Inglebert

    2014-05-01

    Full Text Available In the title compound, C18H19BrN2O4, the chromene unit is not quite planar (r.m.s. deviation = 0.199 Å, with the methyl C atoms lying 0.027 (4 and 1.929 (4 Å from the mean plane of the chromene unit. The six-membered carbocyclic ring of the chromene moiety adopts an envelope conformation, with the dimethyl-substituted C atom as the flap. The methylamine and nitro groups are slightly twisted from the chromene moiety, with C—N—C—O and O—N—C—C torsion angles of 2.7 (4 and −0.4 (4°, respectively. The dihedral angle between the mean plane of the chromene unit and the benzene ring is 85.61 (13°. An intramolecular N—H...O hydrogen bond generates an S(6 ring motif, which stabilizes the molecular conformation. In the crystal, molecules are linked via N—H...O hydrogen bonds, forming hexagonal rings lying parallel to the ab plane. A region of disordered electron density, most probably disordered ethanol solvent molecules, occupying voids of ca 432 Å3 for an electron count of 158, was treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155]. Their formula mass and unit-cell characteristics were not taken into account during refinement.

  14. 1,1′-(Diselanediylbis{[P,P-diphenyl-N-(trimethylsilylphosphorimidoyl]methanylylidene}bis[1,1-diphenyl-N-(trimethylsilyl-λ5-phosphanamine] pentane disolvate

    Directory of Open Access Journals (Sweden)

    Ramalingam Thirumoorthi

    2014-01-01

    Full Text Available The title compound, C62H78N4P4Se2Si4·2C5H12, is made up of two [SeC(PPh2NSiMe3(PPh2NHSiMe3] units related by an inversion center situated at the mid-point of the diselenide bond. It crystallized with two disordered molecules of pentane used as solvent of crystallization. It is a rare example of an antiperiplanar diselenide and exhibits a long Se—Se bond of 2.4717 (8 Å. The Se—C bond length of 1.876 (5 Å is short in comparison with the range of values found for other diselenides (1.91–1.97 Å. The molecule exhibits two intramolecular N—H...N hydrogen bonds. In the crystal, there are no significant intermolecular interactions present. One of the Me3Si– groups is disordered over two positions with a refined occupancy ratio of 0.708 (8:0.292 (8. The contribution of the disordered solvent to the scattering was removed with the SQUEEZE option of PLATON [Spek (2009. Acta Cryst. D65, 148–155]. The solvent contribution has been included in the reported molecular weight and density.

  15. 1,1′-(Diselanediylbis{[P,P-diphenyl-N-(tri­methyl­sil­yl)phospho­rimido­yl]methanylyl­idene})bis­[1,1-diphenyl-N-(tri­methyl­sil­yl)-λ5-phosphanamine] pentane disolvate

    Science.gov (United States)

    Thirumoorthi, Ramalingam; Chivers, Tristram; Laitinen, Risto S.

    2014-01-01

    The title compound, C62H78N4P4Se2Si4·2C5H12, is made up of two [SeC(PPh2NSiMe3)(PPh2NHSiMe3)] units related by an inversion center situated at the mid-point of the diselenide bond. It crystallized with two disordered mol­ecules of pentane used as solvent of crystallization. It is a rare example of an anti­periplanar diselenide and exhibits a long Se—Se bond of 2.4717 (8) Å. The Se—C bond length of 1.876 (5) Å is short in comparison with the range of values found for other diselenides (1.91–1.97 Å). The mol­ecule exhibits two intra­molecular N—H⋯N hydrogen bonds. In the crystal, there are no significant inter­molecular inter­actions present. One of the Me3Si– groups is disordered over two positions with a refined occupancy ratio of 0.708 (8):0.292 (8). The contribution of the disordered solvent to the scattering was removed with the SQUEEZE option of PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]. The solvent contribution has been included in the reported mol­ecular weight and density. PMID:24526971

  16. (R C,S Fe)-1-[3,5-Bis(trifluoro­meth­yl)phen­yl]-3-{1-[2-(diphenyl­phosphan­yl)ferro­cen­yl]eth­yl}thio­urea (unknown solvate)

    Science.gov (United States)

    Ma, Peng-Fei; Zhang, Xiao-Rui; Ma, Jiang-Wei; Chen, Hui; Jiang, Ru

    2013-01-01

    In the molecule of the the title compound, [Fe(C5H5)(C28H22F6N2PS)], the absolute configuration is R C ,SFe. The dihedral angle between the trifluoro­methyl-substituted phenyl ring and the thio­urea plane is 41.8 (9)°. The iron atom is bound to the cyclo­penta­dienyl rings in the typical η5-manner in a close to eclipsed conformation. The crystal structure features N—H⋯S hydrogen bonds, with the S atom as an acceptor for both N—H groups, forming a layered arrangement parallel to (1-10). The two –CF3 groups are each disordered over two positions with refined occupancy rates for the major components of 0.66 (7) and 0.55 (5). The crystal was grown from mixed solvents (n-hexane and ethyl acetate). These solvents are disordered in the crystal and the resulting electron density was found to be uninterpretable. The solvent contribution to the structure factors was taken into account by back-Fourier transformation of all density found in the disordered solvent area using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]. The formula mass and density do not take account of the solvent. PMID:23723760

  17. trans-Dichloridobis{dicyclo­hex­yl[4-(dimethyl­amino)­phen­yl]phosphane-κP}platinum(II) dichloro­methane disolvate

    Science.gov (United States)

    Davis, Wade L.; Meijboom, Reinout

    2012-01-01

    In the title complex, trans-[PtCl2{P(C6H11)2(4-Me2NC6H4)}2]·2CH2Cl2, the PtII atom is located on an inversion centre, resulting in a trans-square-planar geometry. Important geometric parameters are the Pt—P and Pt—Cl bond lengths of 2.3258 (6) and 2.3106 (6) Å, respectively, and the P—Pt—Cl angles of 89.64 (2) and 90.36 (2)°. The effective cone angle for the dicyclo­hex­yl[4-(dimethyl­amino)­phen­yl]phosphane unit was calculated to be 164°. The compound crystallizes with two dichloro­methane solvent mol­ecules; one of which is severely disordered and was treated using the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155]. PMID:23468763

  18. Molecular Detection of Rickettsia amblyommii in Amblyomma americanum Parasitizing Humans

    Science.gov (United States)

    2010-01-01

    Maeda, K, Markowitz, N, Hawley, RC, Ristic, M, et al. Human infection with Ehrlichia canis , a leukocytic rickettsia. N Eng! J Med 1987; 316:853-856...lone star tick human pathogens Ehrlichia chaffenesis (human monocytic ehrlichiosis [HMEJ) and Ehrlichia ezoingii (E. ezoingii ehrlichiosis [EWE...Paddock, CD, et al. Ehrlichia ewingii, a newly recognized agent of human ehrlichiosis. N Engl J Med 1999; 341:148-155. Burgdorfer, W, Hayes, S

  19. Changes in Spatiotemporal Differences Between the Sexes due to Paired Walking

    Science.gov (United States)

    2016-06-29

    Automatic Face and Gesture Recognition, 2002. Proceedings. Fifth IEEE International Conference on, ’Editor’^’Editors’, 2002, IEEE . 148-155. 13. Li...X., et al., Gait components and their application to gender recognition. Systems, Man, and Cybernetics, Part C: Applications and Reviews, IEEE ...classification with support vector machines, in Automatic Face and Gesture Recognition, 2000. Proceedings. Fourth IEEE International Conference on

  20. 3-(1H-Indol-3-yl-2-(2-nitrobenzenesulfonamidopropanoic acid including an unknown solvate

    Directory of Open Access Journals (Sweden)

    Islam Ullah Khan

    2012-07-01

    Full Text Available In the title compound, C17H15N3O6S, which crystallized with highly disordered methanol and/or water solvent molecules, the dihedral angle between the the indole and benzene ring systems is 5.3 (2°, which allows for the formation of intramolecular π–π stacking interactions [centroid–centroid separations = 3.641 (3 and 3.694 (3 Å] and an approximate overall U-shape for the molecule. In the crystal, dimers linked by pairs of Ns—H...Oc (s = sulfonamide and c = carboxylate hydrogen bonds generate R22(10 loops, whereas Ni—H...π (i = indole interactions lead to chains propagating in [100] or [010]. Together, these lead to a three-dimensional network in which the solvent voids are present as intersecting (two-dimensional systems of [100] and [010] channels. The title compound was found to contain a heavily disordered solvent molecule, which could be methanol or water or a mixture of the two. Due to its uncertain nature and the unresolvable disorder, the data were processed with the SQUEEZE option in PLATON [Spek (2009. Acta Cryst. D65, 148–155], which revealed 877.8 Å3 of solvent-accessible volume per unit cell and 126 electron-units of scattering density or 109.7 Å3 (16 electron units per organic molecule.. This was not included in the calculations of overall formula weight, density and absorption coefficient.

  1. Octakis(dimethyl sulfoxide-κOcerium(III μ6-oxido-dodeca-μ2-oxido-hexaoxidohexamolybdate(VI dimethyl sulfoxide tetrasolvate

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    Arbia Ben Khélifa

    2012-07-01

    Full Text Available The title complex, [Ce(C2H6OS8]2[Mo6O19]3·4C2H6OS, was obtained as a byproduct of the reaction of [(C4H94N]2[Mo6O19] with Ce(NO33·6H2O and phthalic acid in dimethylsulfoxide solution. The asymmetric unit consists of a complex [Ce(C2H6OS8]3+ cation, one and a half of the Lindqvist-type [Mo6O19]2− polyanions and two dimethylsulfoxide solvent molecules; the half polyanion lies on an inversion center. The Ce3+ ion is coordinated by eight dimethylsulfoxide ligands through the O atoms in the form of a distorted square antiprism. The Ce—O bond lengths range from 2.429 (6 to 2.550 (5 Å. The cohesion of the structure is ensured by S...O [3.115 (6, 3.242 (10 and 3.12 (3 Å], O...O [3.037 (10 Å] and C—H...O interactions between cations and anions. The S and C atoms of a dmso ligand are disordered over three sites in a 0.45:0.30:0.25 ratio. The dimethylsulfoxide solvent molecules are highly disordered and could not be modelled successfully; their contribution was therefore removed from the refinement using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155]. Potential solvent-accessible voids of 500.0 Å3 occur in the crystal structure.

  2. Pallidol hexaacetate ethyl acetate monosolvate

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    Qinyong Mao

    2013-07-01

    Full Text Available The entire molecule of pallidol hexaacetate {systematic name: (±-(4bR,5R,9bR,10R-5,10-bis[4-(acetyloxyphenyl]-4b,5,9b,10-tetrahydroindeno[2,1-a]indene-1,3,6,8-tetrayl tetraacetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate molecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009. Acta Cryst. D65, 148–155]; the crystallographic data take into account the presence of the solvent. In pallidol hexaacetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100 Å is 54.73 (6°, indicating a significant fold in the molecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70 (5° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C—O(carboxy—C—C torsion angles = −70.24 (14, −114.43 (10 and −72.54 (13°]. In the crystal, a three-dimensional architecture is sustained by C—H...O interactions which encompass channels in which the disordered ethyl acetate molecules reside.

  3. Advances in membrane protein crystallography: in situ and in meso data collection

    Energy Technology Data Exchange (ETDEWEB)

    Weyand, Simone, E-mail: sw644@cam.ac.uk [Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA (United Kingdom); Tate, Christopher G., E-mail: sw644@cam.ac.uk [MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH (United Kingdom)

    2015-05-23

    Membrane protein structural biology has made tremendous advances over the last decade but there are still many challenges associated with crystallization, data collection and structure determination. Two independent groups, Axford et al. [(2015), Acta Cryst. D71, 1228–1237] and Huang et al. [(2015), Acta Cryst. D71, 1238–1256], have published methods that make a major contribution to addressing these challenges.

  4. Bis(1,3-dimethyl-1H-imidazolium hexafluorosilicate methanol 0.33-solvate

    Directory of Open Access Journals (Sweden)

    Maxim V. Borzov

    2013-08-01

    Full Text Available The title compound, 6C5H9N2+·3SiF62−·CH3OH, (I, was prepared by recrystallization of the crude salt from methanol along with solvent-free 2C5H9N2+·SiF62− (II. Crystals of these solvatomorphs can be separated manually. The solvate (I crystallizes in a rare hexagonal space group P6/mcc. Its asymmetric unit comprises one half of an imidazolium cation bisected by the crystallographic m-plane, one-sixth and one-twelfth of two crystallographically independent SiF62– dianions (Si atoms are located on the 3.2 and 6/m inversion centres, and one-twelfth of a methanol molecule (C atoms are situated on the 622 inversion centres, other atoms are disordered between general positions. In (I, all F atoms of 3.2-located SiF62– dianions participate in the formation of symmetry-equivalent contacts to the H atoms of imidazolium fragments, thus forming rod-type ensembles positioned on the -6 axes. These `pillar' rods are, in turn, F...H interlinked through SiF62– dianions disordered around the 6/m centres. The twelvefold disordered methanol molecules are appended to this array by O—H...F hydrogen bonds to the 6/m located SiF62– dianions. In terms of graph-set notation, the first and second level networks in (I are N1 = C22(7[3R44(14]D22(4 and N2 = D22(5 (C—H...O hydrogen bonds are not considered. After locating all symmetrically independent atoms in the cation and anions, there remained a strong (> 3 e Å−3 residual electron density peak located at the 622 inversion centre. Treatment of this pre-refined model with the SQUEEZE procedure in PLATON [Spek (2009. Acta Cryst. D65, 148–155] revealed two voids per unit cell, indicative of the presence of the solvent methanol molecule disordered about the 622 inversion centre.

  5. μ-Oxalato-bis[bis(triphenylphosphinecopper(I] dichloromethane disolvate. Corrigendum

    Directory of Open Access Journals (Sweden)

    Andrew D. Royappa

    2014-10-01

    Full Text Available An erroneous claim in the paper by Royappa et al. [Acta Cryst. (2013, E69, m126] is corrected and a reference added for a previously published report of a closely related structure.

  6. A neo-clerodane diterpene from Teucrium tomentosum. Corrigendum

    Directory of Open Access Journals (Sweden)

    S. Soundarya Devi

    2009-06-01

    Full Text Available The chemical name of the title compound in the paper by Devi, Malathi, Rajan, Aravind, Krishnakumari & Ravikumar [Acta Cryst. (2004, E60, o117–o119] is corrected and the structural diagram is updated.

  7. A neo-clerodane diterpene from Teucrium tomentosum. Corrigendum

    Science.gov (United States)

    Devi, S. Soundarya; Malathi, R.; Rajan, S. S.; Aravind, S.; Krishnakumari, G. N.; Ravikumar, K.

    2009-01-01

    The chemical name of the title compound in the paper by Devi, Malathi, Rajan, Aravind, Krishnakumari & Ravikumar [Acta Cryst. (2004), E60, o117–o119] is corrected and the structural diagram is updated. PMID:21582975

  8. Abstracts: Sagmore 9 Conference on Charge, Spin and Momentum Densities Held in Luso-Bussaco, Portugal on 26 June-2 July 1988

    Science.gov (United States)

    1988-07-01

    counter, for two different orientations (a vertical , then b vertical ) of the same single crystal, at 21 under an applied field of 5 tels.. The whole set...Cnyst.33z.1777 (I)Shbs.Eikhawa A Salto (1985) Acts Cryst. C41.1l C)1Ikkhemjehh.Sl to.ia~ts A luota(SU7 Act& Cryst. 343. 83. 28 P2.4 L. BRAMMER and K.D

  9. Molecular Engineering of Liquid Crystal Polymers by Living Polymerization. 14. Synthesis and Characterization of Binary Copolymers of Omega-4-Cyano-4’-Biphenyl)oxyAlkyl Vinyl Ethers Containing Undecanyl and Hexyl Pentyl and Propyl, and Undecanyl and Propyl Pairs of Alkyl Groups

    Science.gov (United States)

    1991-04-10

    Noel, C. Polym. Bull. 1986, 15, 341; Lacoudre, N.; Le Borgue , A.; Spassky, N.; Vairon, J. P.; Le Barny, P.; Dubois, . C.; Esselin, S.; Friedrich, C...Noel, C. Mol. Cryst. Liq. Cryst. 1988, 155, 113; Spassky, N.; Lacoudre, N.; Le Borgue , A.; Vairon J. P.; Jun, C. L.; Friedrich, C.; Noel, C. Makromol...Chem. Macromol. Symp. 1989, 24, 271; Legrand, C.; Le Borgue , A.; Bunel, C.; Lacoudre, N.; Le Barny, P.; Spassky, N.;Vairon, 3. P. Makromol. Chem

  10. Crystal structure and Hirshfeld surface analysis of 1-carboxy-2-(3,4-dihydroxyphenyl)ethan-1-aminium chloride 2-ammonio-3-(3,4-dihydroxyphenyl)propanoate: a new polymorph of l-dopa HCl and isotypic with its bromide counterpart

    OpenAIRE

    Perumal Kathiravan; Thangavelu Balakrishnan; Perumal Venkatesan; Kandasamy Ramamurthi; María Judith Percino; Subbiah Thamotharan

    2016-01-01

    The title molecular salt, C9H12NO4+·Cl−·C9H11NO4, is isotypic with that of the bromide counterpart [Kathiravan et al. (2016). Acta Cryst. E72, 1544–1548]. The title salt is a second monoclinic polymorph of the l-dopa HCl structure reported earlier in the monoclinic space group P21 [Jandacek & Earle (1971). Acta Cryst. B27, 841–845; Mostad & Rømming (1974). Acta Chemica Scand. B28, 1161–1168]. In the title compound, monoclinic space group I2, one of the dopa molecules has a positive charge wit...

  11. Crystal structure and Hirshfeld surface analysis of 1-carb­oxy-2-(3,4-di­hydroxy­phen­yl)ethan-1-aminium chloride 2-ammonio-3-(3,4-di­hydroxy­phen­yl)propano­ate: a new polymorph of l-dopa HCl and isotypic with its bromide counterpart

    OpenAIRE

    Kathiravan, Perumal; Balakrishnan, Thangavelu; Venkatesan, Perumal; Ramamurthi, Kandasamy; Percino, María Judith; Thamotharan, Subbiah

    2016-01-01

    The title mol­ecular salt, C9H12NO4 +·Cl−·C9H11NO4, is isotypic with that of the bromide counterpart [Kathiravan et al. (2016 ▸). Acta Cryst. E72, 1544–1548]. The title salt is a second monoclinic polymorph of the l-dopa HCl structure reported earlier in the monoclinic space group P21 [Jandacek & Earle (1971 ▸). Acta Cryst. B27, 841–845; Mostad & Rømming (1974 ▸). Acta Chemica Scand. B28, 1161–1168]. In the title compound, monoclinic space group I2, one of the dopa mol­ecules has a positive c...

  12. 平面金属螯合物为桥基的类梯形盘状液晶高分子

    Institute of Scientific and Technical Information of China (English)

    谢萍; 申仲荣; 刘宇彪; 范震; 张榕本

    2000-01-01

    [1] Adam D., Closs F., Funhoff D., Haarer D., Ringsdorf H., Schuhmacher P., Siememsmeyer K.,Phys. Rev. Lett., 1993, 70:457[2] Adam D., Schuhmacher P., Simmerer J., Hussling L., Siememsmeyer K., Etzbach K. H.,Ringsdorf H., Haarer D., Nature, 1994, 371:141[3] Giroud-Godquin A. M.,and Billard J.,Mol. Cryst. liq. Cryst., 1981,66:147[4] Kohne B. and Praefcke K., Angew. Chem., 1984, 96:70[5] Liu Yb., Liu Cq., Cui L., Fan Z., Xie P., and Zhang Rb., Liquid Crystals, 2000,27:5.

  13. Solid State Raman Materials Characterization and Raman Shifting Of 1.3 Micron Laser Radiation

    Science.gov (United States)

    2000-06-01

    Cryst. Liq. Cryst. 123 (1985) 295. 5.7. Ichiro Hatta, Thermochimica Acta 304/305 (1997) 27. 5.8. K. Ema, H. Yao, Thermochimica Acta 304/305 (1997) 157...5.9. Yasuo Saruyama, Thermochimica Acta 304/305 (1997) 171. 5.10. M. Castro, J. A. Puertolas, Thermochimica Acta 304/305 (1997) 291. 5.11. D. Finotello...S. Qian, G. S. Iannacchione, Thermochimica Acta 304/305 (1997) 303. 5.12. A.A. Minakov, Yu.V. Bugoslavsky, C. Schick, Thermochimica Acta 317 (1998

  14. Hardness and incipient plasticity in silicate glasses

    DEFF Research Database (Denmark)

    Kjeldsen, Jonas; Smedskjær, Morten Mattrup; Mauro, John C.;

    2014-01-01

    The scaling of Vickers hardness (Hv) in oxide glasses with varying network modifier/modifier ratio is manifested as either a positive or negative deviation from linearity with a maximum deviation at the ratio of about 1:1. In an earlier study [J. Kjeldsen et al., J. Non-Cryst. Solids 369,61(2013)......The scaling of Vickers hardness (Hv) in oxide glasses with varying network modifier/modifier ratio is manifested as either a positive or negative deviation from linearity with a maximum deviation at the ratio of about 1:1. In an earlier study [J. Kjeldsen et al., J. Non-Cryst. Solids 369...

  15. Proceedings of Symposium F on New Aspects on the Growth, Characterization and Applications of CdTe and Related Cd Rich Alloys of the 1992 E-MRS Spring Conference held in Strasbourg, France on June 2 - 5, 1992

    Science.gov (United States)

    1992-01-01

    diffusion-induced changes in the low energy part of the bound-exciton The authors are indebted to M. Wienecke and C. Albers from the Humboldt-Universitit...Neubert, T. Boeck, P. M6ck, L. Parthier, K. Jacobs and E. Kropp, J. Cryst. Growth, 118 (1992)204. 11 C. Albers and M. Wienecke, Cryst. Res. Technol., 22...process. In fact, the space charge field is anni - levels induces a periodic distribution of free electrons hilated and free carriers can diffuse again

  16. CREDO: a structural interactomics database for drug discovery.

    Science.gov (United States)

    Schreyer, Adrian M; Blundell, Tom L

    2013-01-01

    CREDO is a unique relational database storing all pairwise atomic interactions of inter- as well as intra-molecular contacts between small molecules and macromolecules found in experimentally determined structures from the Protein Data Bank. These interactions are integrated with further chemical and biological data. The database implements useful data structures and algorithms such as cheminformatics routines to create a comprehensive analysis platform for drug discovery. The database can be accessed through a web-based interface, downloads of data sets and web services at http://www-cryst.bioc.cam.ac.uk/credo. Database URL: http://www-cryst.bioc.cam.ac.uk/credo.

  17. Practical approach for production of bacteria-based agent-contained light weight aggregates to make concrete self-healing

    NARCIS (Netherlands)

    Mors, R.M.; Jonkers, H.M.

    2013-01-01

    A functional experimental concrete system has been developed in our lab, in which a two component bacteria-based healing agent contained in a protective reservoir is included in the concrete mixture. Incorporated bacteria have the potential to produce copious amounts of calcium carbonate based cryst

  18. 75 FR 6424 - Self-Regulatory Organizations; NYSE Amex LLC; Notice of Filing and Immediate Effectiveness of...

    Science.gov (United States)

    2010-02-09

    .... 166 ANF Abercrombie & 187 MMM 3M Co. Fitch Co. 172 APC Anadarko Petroleum 140 MU Micron Technology... Occidental Petroleum Corp. 190 BCRX BioCryst 158 PARD Poniard Pharmaceuticals Pharmaceuticals Inc. Inc. 218... principles of trade, remove impediments to and perfect the mechanisms of a free and open market and...

  19. Vacancy ordering and superstructure formation in dry and hydrated strontium tantalate perovskites: A TEM perspective

    DEFF Research Database (Denmark)

    Ashok, Anuradha M.; Haavik, Camilla; Norby, Poul

    2014-01-01

    Crystal structures of Sr4(Sr2Ta2)O11 and Sr4(Sr1.92Ta2.08)O11.12, synthesized by solid state reaction technique in dry and hydrated state have been studied mainly using Transmission Electron Microscopy. Due to the lesser ability of X-rays to probe details in oxygen sublattice, the change in cryst...

  20. Neutron and X-ray diffraction study of ferrite nanocrystals obtained by microwave-assisted growth. A structural comparison with the thermal synthetic route. Corrigendum

    Science.gov (United States)

    Solano, Eduardo; Frontera, Carlos; Puente Orench, Inés; Puig, Teresa; Obradors, Xavier; Ricart, Susagna; Ros, Josep

    2014-01-01

    In the paper by Solano et al. ▶ [J. Appl. Cryst. (2014), 47, 414–420], Inés Puente Orench is missing from the list of authors. The complete list of authors should be Eduardo Solano, Carlos Frontera, Inés Puente Orench, Teresa Puig, Xavier Obradors, Susagna Ricart and Josep Ros. PMID:25242916

  1. European Symposium on X-Ray Topography and High Resolution Diffraction (2nd) Held in Berlin, Germany on 5-7 September 1994. Programme and Abstracts

    Science.gov (United States)

    1994-09-07

    N L Andrew Philips Research Laboratories, Cross-Oak Lane, Redhill, RH! 5HA, U.K. A Saced6n, E Calleja Dept. Ingenieria Electr6nica, E. T. S. I. T.. U...Matematica e Fisica - 62032 CAMERINO (Italy) * I lnst. Cryst. Russian Acad. of Science, MOSCOW (Rlussia) Si/Ge superlattices (SL) have recently

  2. A test on the statistics of derived intensities

    NARCIS (Netherlands)

    de With, G.; Feil, D.

    1976-01-01

    Variances of X-ray reflexions calculated with the procedure as proposed by McCandlish, Stout & Andrews [Acta Cryst. (1975), A31, 245-249] have been tested against variances determined in an independent way. A satisfying agreement is obtained

  3. Holographic recording in thiophene-based polyester

    DEFF Research Database (Denmark)

    Matharu, Avtar Singh; Chambers-Asman, David; Jeeva, Shehzad

    2008-01-01

    The synthesis and optical data storage properties of a side-chain thiophene-phenyl azopolyester ThPhAzoP.ol is reported. The polyester is derived from diphenyl tetradecanedioate and a thiophenebased liquid crystalline diol which exhibits a short-lived enantiotropic SmA phase (Cryst 177.7 SmA 180...

  4. Domain Modeling: NP_001002912.3 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_001002912.3 chr1 CRYSTAL STRUCTURE OF TROPOMYOSIN AT 7 ANGSTROMS RESOLUTION IN THE SPERMINE-INDUCED CRYST...AL FORM c1c1gd_ chr1/NP_001002912.3/NP_001002912.3_apo_256-533.pdb psi-blast 0 ...

  5. Domain Modeling: NP_001095133.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_001095133.1 chr1 CRYSTAL STRUCTURE OF TROPOMYOSIN AT 7 ANGSTROMS RESOLUTION IN THE SPERMINE-INDUCED CRYST...AL FORM c1c1gd_ chr1/NP_001095133.1/NP_001095133.1_apo_7-270.pdb psi-blast 0 ...

  6. Domain Modeling: NP_001001924.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_001001924.1 chr8 CRYSTAL STRUCTURE OF TROPOMYOSIN AT 7 ANGSTROMS RESOLUTION IN THE SPERMINE-INDUCED CRYST...AL FORM c1c1gd_ chr8/NP_001001924.1/NP_001001924.1_apo_2-263.pdb psi-blast 0 ...

  7. Domain Modeling: NP_001032519.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_001032519.1 chr4 CRYSTAL STRUCTURE OF TROPOMYOSIN AT 7 ANGSTROMS RESOLUTION IN THE SPERMINE-INDUCED CRYST...AL FORM c1c1gd_ chr4/NP_001032519.1/NP_001032519.1_apo_251-515.pdb psi-blast 0 ...

  8. Domain Modeling: NP_001001924.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_001001924.1 chr8 CRYSTAL STRUCTURE OF TROPOMYOSIN AT 7 ANGSTROMS RESOLUTION IN THE SPERMINE-INDUCED CRYST...AL FORM c1c1gd_ chr8/NP_001001924.1/NP_001001924.1_apo_729-1013.pdb psi-blast 0 ...

  9. Domain Modeling: NP_001035089.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_001035089.1 chr6 CRYSTAL STRUCTURE OF TROPOMYOSIN AT 7 ANGSTROMS RESOLUTION IN THE SPERMINE-INDUCED CRYST...AL FORM c1c1gd_ chr6/NP_001035089.1/NP_001035089.1_apo_1285-1557.pdb psi-blast 0 ...

  10. Domain Modeling: NP_001078823.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_001078823.1 chrX CRYSTAL STRUCTURE OF TROPOMYOSIN AT 7 ANGSTROMS RESOLUTION IN THE SPERMINE-INDUCED CRYST...AL FORM c1c1gd_ chrX/NP_001078823.1/NP_001078823.1_apo_249-522.pdb psi-blast 0 ...

  11. Domain Modeling: NP_001018001.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_001018001.1 chr1 CRYSTAL STRUCTURE OF TROPOMYOSIN AT 7 ANGSTROMS RESOLUTION IN THE SPERMINE-INDUCED CRYST...AL FORM c1c1gd_ chr1/NP_001018001.1/NP_001018001.1_apo_3-274.pdb psi-blast 0 ...

  12. Integration of Generic Multi-dimensional Model and Operational Policies for Batch Cooling Crystallization

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli; Singh, Ravendra; Sin, Gürkan

    Crystallization processes form an important class of separation methods that are frequently used in the chemical, the pharmaceutical and the food industry. The specifications of the crystal product are usually given in terms of crystal size, shape and purity. In order to predict the desired cryst...

  13. Systematic Modelling and Crystal Size Distribution Control for Batch Crystallization Processes

    DEFF Research Database (Denmark)

    Abdul Samad, Noor Asma Fazli; Singh, Ravendra; Sin, Gürkan

    Crystallization processes form an important class of separation methods that are frequently used in the chemical, the pharmaceutical and the food industry. The specifications of the crystal product are usually given in terms of crystal size, shape and purity. In order to predict the desired cryst...

  14. Solid State Research.

    Science.gov (United States)

    2007-11-02

    Kobayashi and T. Makimoto , Jpn. J. Appl. Phys. 24, L824 (1985). 12. A. C. Jones and S. A. Rushworth, J. Cryst. Growth 106, 253 (1990). 13. W. S. Hobson, T... going to HBr at low chuck power the oxide etch rate is reduced even further. In addition, a small amount of oxygen was added in the overetch step. This

  15. Dynamic quantum crystallography

    DEFF Research Database (Denmark)

    Hoser, Anna A.; Madsen, Anders Østergaard

    2017-01-01

    In the first paper of this series [Hoser & Madsen (2016). Acta Cryst. A72, 206-214], a new approach was introduced which enables the refinement of frequencies of normal modes obtained from ab initio periodic computations against single-crystal diffraction data. In this contribution, the performan...

  16. Comment on `Magic strains in face-centered and body-centered cubic lattices'

    NARCIS (Netherlands)

    Waal, van de Benjamin W.

    1990-01-01

    The six symmetry-related so-called magic strain tensors that transform a f.c.c. lattice (or a b.c.c. lattice) into itself, which have been reported recently by Boyer [Acta Cryst. (1989), A45, FC29-FC32] are not unique: an infinite number of displacement tensors can be constructed that transform one

  17. Lithium Hydroxide Dihydrate: A New Type of Icy Material at Elevated Pressure

    Science.gov (United States)

    2011-01-01

    M. Jansen, J. Appl. Crystallogr. 32, 864 (1999). 17A. L. Speck, PLATON , a multipurpose crystallographic tool Utrecht University, Utrecht, The...Netherlands, 2001. See http://www.cryst.chem. uu.nl/ platon /. 18G. Kresse and J. Furthmuller, Comput. Mater. Sci. 6, 15 (1996). 19G. Kresse and J. Hafner, J

  18. Electrostatic Molecular Interaction from X-ray Diffraction Data. II. Test on Theoretical Pyrazine Data

    NARCIS (Netherlands)

    Feil, Dirk; Moss, Grant

    1983-01-01

    In a previous paper [Moss & Feil (1981). Acta Cryst. A37, 414-421] a method was reported to calculate the electrostatic potential and the electrostatic interaction energy from single-crystal X-ray diffraction data. The method was applied to experimental pyrazine data; however, owing to the relativel

  19. Laterally Overgrown Structures as Substrates for Lattice Mismatched Epitaxy

    Science.gov (United States)

    2002-06-03

    Chocho , Jpn. J. Appl. Phys. 36 (1997) Growing the layers standing free above the mask seems L1568.[3] T. Nishinaga, Cryst. Prop. Prep. 31 (1991) 92. to be...moto, M. Sano, K. Chocho , Jpn. J. Appl. Phys. 36 (1997) 5S1 (2000) W2.3, L1568. [38] I. Kidoguchi, A. Ishibashi, G. Sugahara, Y. Ban, Appl. Phys

  20. Optimization of control parameters of CdZnTe ACRT-Bridgman single crystal growth

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    [1]Kennedey, J. J., Amirtharaj, P. M., Boyd, P. R. Et al., Growth and characterization of Cd1-xZnxTe and Hg1-yZnyTe, J. Cryst. Growth, 1988, 86: 93-99.[2]Tanaka, A., Masa, Y., Seto, S. et al., Zinc and selenium co-doped CdTe substrates lattice matched to HgCdTe, J. Cryst. Growth, 1989, 94: 166-170.[3]Sen, S., Stanard, J. E., Developments in the bulk growth of Cd1-xZnxTe for substrates, Prog. Crystal Growth and Charact., 1994, 29: 253-273.[4]Azoulay, M., Rotter, S., Gafni, G. et al., Zinc segregation in CdZnTe grown under Cd/Zn partial pressure control, J. Cryst. Growth, 1992, 117: 276-280.[5]Lee, T. S., Lee, S. B., Kim, J. M. et al., Vertical Bridgman techniques to homogenize zinc composition of CdZnTe substrates, J. Electronic Materials, 1995, 24: 1057-1059.[6]Mühlberg, M., Rudolph, P., Genzel, C. Et al., Crystalline and chemical quality of CdTe and Cd1-xZnxTe grown by the Bridgman method in low temperature gradients, J. Cryst. Growth, 1990, 101: 275-280.[7]Cheuvart, P., El-Hanani, U., Schneider, D. et al., CdTe and CdZnTe crystal growth by horizontal Bridgman technique, J. Cryst. Growth, 1990, 101: 270-274.[8]Lu, Y. C., Shiau, J. J., Fiegelson, R. S. et al., Effect of vibrational stirring on the quality of Bridgman-grown CdTe, J. Cryst. Growth, 1990, 102: 807-813.[9]Butler, J. F., Doty, F. P., Apotovsky, B. Et al., γ-ray and X-ray detectors manufactured from Cd1-xZnxTe grown by a high-pressure Bridgman method, Mater. Sci. & Eng. B, 1993, 16: 291-295.[10]Capper, P., The role of accelerated crucible rotation in the growth of Hg1-xCdxTe and CdTe/CdZnTe, Prog. Crystal Growth and Charact., 1994, 28: 1-55.[11]Schulz-Dubois, E. O., Accelerated crucible rotation: hydrodynamics and stirring effect, J. Cryst. Growth, 1971, 12: 81-87.[12]Capper, P., Gosney, J. J. G., Jones, C. L. et al., Fluid flows in tall narrow containers by ACRT, Journal of Electronic Materials, 1986 15(6): 361-370.[13]Distanov, V. E., Kirdyashkin, A

  1. 23 CFR Appendix to Subpart F of... - Alternate Method of Determining the Color of Retroreflective Sign Materials and Pavement Marking...

    Science.gov (United States)

    2010-04-01

    ... with CIE 2° Standard Observer and 45/0 (0/45) Geometry and CIE Standard Illuminant D65. Color... CIE Standard Illuminant D65. Color Luminance Factor Limits (Y) Min Max YF* Fluorescent Orange 25 None... Angle of +5° and CIE Standard Illuminant A. Color Chromaticity Coordinates 1 x y 2 x y 3 x y 4 x...

  2. Determinação do ponto de colheita na produção de alho Determination of the harvest date for garlic cultivars

    Directory of Open Access Journals (Sweden)

    Carlos Manoel de Oliveira

    2003-09-01

    Full Text Available O ponto de colheita de cultivares de alho tropical foi obtido através de um experimento conduzido na UFLA (MG, no delineamento de blocos casualizados, em esquema fatorial 4 x 5, com quatro repetições, avaliando quatro cultivares (Gigante Curitibanos, Gravatá, Gigante Lavínia e Gigante Roxo e cinco épocas de colheita (134, 141, 148, 155 e 162 dias após o plantio. Avaliou-se a produtividade total de plantas, produtividade total de bulbos e características físico-químicas (teor de sólidos solúveis, acidez titulável e índice de pH. Os resultados obtidos permitiram verificar que as épocas de colheita influenciaram significativamente a produção e as características físico-químicas. A máxima produtividade foi obtida aos 148 e 156 dias após plantio, períodos em que se observou também aumento nas concentrações de sólidos solúveis e ácidos orgânicos no suco do alho.The harvest point for tropical garlic cultivars was determined through an experiment carried out in the Universidade Federal de Lavras, Brazil, with randomized block design, in a 4 x 5 factorial scheme, four replications, testing four cultivars: Gigante Curitibanos, Gravatá, Gigante Lavínia and Gigante Roxo and five harvesting dates: 134, 141, 148, 155 and 162 days after planting. The total yield of plant, total yield of garlic bulbs and physical-chemical characteristics (soluble acids content, titrable acidity and pH indices were determined. The harvest date influenced significantly the yield and physical-chemical characteristics: Maximum yield, soluble solids concentration, and organic acids in garlic juice were obtained when harvesting at 148 and 156 days after planting date.

  3. Crystallographic data processing for free-electron laser sources

    Energy Technology Data Exchange (ETDEWEB)

    White, Thomas A., E-mail: taw@physics.org; Barty, Anton; Stellato, Francesco [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Holton, James M. [University of California, San Francisco, CA 94158 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Kirian, Richard A. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); Arizona State University, Tempe, AZ 85287 (United States); Zatsepin, Nadia A. [Arizona State University, Tempe, AZ 85287 (United States); Chapman, Henry N. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); University of Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

    2013-07-01

    A processing pipeline for diffraction data acquired using the ‘serial crystallography’ methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A processing pipeline for diffraction data acquired using the ‘serial crystallography’ methodology with a free-electron laser source is described with reference to the crystallographic analysis suite CrystFEL and the pre-processing program Cheetah. A detailed analysis of the nature and impact of indexing ambiguities is presented. Simulations of the Monte Carlo integration scheme, which accounts for the partially recorded nature of the diffraction intensities, are presented and show that the integration of partial reflections could be made to converge more quickly if the bandwidth of the X-rays were to be increased by a small amount or if a slight convergence angle were introduced into the incident beam.

  4. Symmetry elements in space groups and point groups. Addenda to two IUCr reports on the nomenclature of symmetry.

    Science.gov (United States)

    Flack, H D; Wondratschek, H; Hahn, T; Abrahams, S C

    2000-01-01

    The definition of 'symmetry element' given in the Report of the IUCr Ad-Hoc Committee on the Nomenclature of Symmetry by de Wolff et al. [Acta Cryst. (1989). A45, 494-499] is shown to contain an ambiguity in the case of space groups P6/m, P6/mmm, P6/mcc and point groups 6/m and 6/mmm. The ambiguity is removed by redefining the 'geometric element' as a labelled geometric item in which the label is related to the rotation angle of the rotation or rotoinversion symmetry operation. The complete set of different types of glide plane is shown to contain three more than the 15 that are illustrated in the 1992 Report by de Wolff et al. [Acta Cryst. (1992). A48, 727-732].

  5. A nanoscale characterisation of extended defects in glassy-like As{sub 2}Se{sub 3} semiconductors with PAL technique

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O.; Kovalskiy, A.; Filipecki, J.; Hyla, M.; Kozdras, A

    2003-12-31

    A meaningful interpretation of positron lifetime characteristics for glassy-like g-As{sub 2}Se{sub 3} is developed taking into account calculations of Jensen et al. (J. Non-Cryst. Solids 170 (1994) 57) for positrons trapped by free-volume extended defects in orthorhombic As{sub 2}Se{sub 3} and void volume distribution for 146-atoms layer-biased model of amorphous As{sub 2}Se{sub 3} presented by Popescu (J. Non-Cryst. Solids 35-36 (1980) 549). The obtained results are compared for samples having different thermal pre-history. Two groups of experimental results with close lifetime characteristics are distinguished for each of the investigated samples. This feature is explained in terms of average positron lifetime by applying two-state positron trapping model for mathematical treatment of the obtained spectra.

  6. Serial femtosecond crystallography datasets from G protein-coupled receptors.

    Science.gov (United States)

    White, Thomas A; Barty, Anton; Liu, Wei; Ishchenko, Andrii; Zhang, Haitao; Gati, Cornelius; Zatsepin, Nadia A; Basu, Shibom; Oberthür, Dominik; Metz, Markus; Beyerlein, Kenneth R; Yoon, Chun Hong; Yefanov, Oleksandr M; James, Daniel; Wang, Dingjie; Messerschmidt, Marc; Koglin, Jason E; Boutet, Sébastien; Weierstall, Uwe; Cherezov, Vadim

    2016-08-01

    We describe the deposition of four datasets consisting of X-ray diffraction images acquired using serial femtosecond crystallography experiments on microcrystals of human G protein-coupled receptors, grown and delivered in lipidic cubic phase, at the Linac Coherent Light Source. The receptors are: the human serotonin receptor 2B in complex with an agonist ergotamine, the human δ-opioid receptor in complex with a bi-functional peptide ligand DIPP-NH2, the human smoothened receptor in complex with an antagonist cyclopamine, and finally the human angiotensin II type 1 receptor in complex with the selective antagonist ZD7155. All four datasets have been deposited, with minimal processing, in an HDF5-based file format, which can be used directly for crystallographic processing with CrystFEL or other software. We have provided processing scripts and supporting files for recent versions of CrystFEL, which can be used to validate the data.

  7. A third monoclinic polymorph of 3,4,5-trihydroxybenzoic acid monohydrate

    Directory of Open Access Journals (Sweden)

    Güneş Demirtaş

    2011-06-01

    Full Text Available The title compound, C7H6O5·H2O, is a new polymorph of the structures reported by Jiang et al. (2000 [Acta Cryst. C56, 594–595] and Okabe et al. (2001 [Acta Cryst. E57, o764–o766]. The gallic acid molecule is essentially planar (r.m.s. deviation = 0.550 Å. An intramolecular O—H...O hydrogen bond occurs in the gallic acid molecule, which is linked to the water molecule by a further O—H...O hydrogen bond. In the crystal, the components are linked by O—H...O hydrogen bonds. The hydrogen-bonding pattern differs from those reported for the previous polymorphs.

  8. Anaplastic lymphoma kinase positive large B-cell lymphoma: Literature review and report of an endoscopic fine needle aspiration case with tigroid backgrounds mimicking seminoma.

    Science.gov (United States)

    Sakr, Hany; Cruise, Michael; Chahal, Prabhleen; Cotta, Claudiu; Cook, James; Chalikonda, Sricharan; Rosenblatt, Steven; Hamadeh, Fatima; Al-Nourhji, Omar; Sturgis, Charles D

    2017-02-01

    Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK+ LBCL) is a rare distinct type of non-Hodgkin's lymphoma that arises in association with alterations of the ALK gene. This distinct disease entity is typically associated with an aggressive clinical course and appears in light microscopic preparations as a monomorphic population of large, immunoblast-like cells. In this report, we describe a case of ALK+ LBCL diagnosed by transgastric endoscopic ultrasound-guided fine needle aspiration (EUS FNA) of splenic hilar lymph nodes. Modified Giemsa stained direct smears from the FNA sample demonstrated large lesional cells with foamy cytoplasm and macronucleoli admixed with small lymphocytes in tigroid backgrounds, mimicking the cytologic appearance of seminoma. Ancillary immunohistochemical studies subsequently confirmed the diagnosis of ALK+ LBCL with the lesional cells being immunoreactive for CD138, VS38c, MUM1, ALK1, and lambda light chain. The cohesiveness of the cells, the cellular morphology, and the tigroid backgrounds were all pitfalls for accurate diagnosis of this rare specific type of lymphoid malignancy by cytology. To our knowledge this is the first case report detailing the diagnosis of ALK+ LBCL by EUS FNA and the first report describing a glycogen-rich tigroid background in direct FNA smears. Establishing a refined diagnosis in cases of this rare form of LBCL is necessary, as therapies targeting ALK may be of value in clinical management. Diagn. Cytopathol. 2017;45:148-155. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  9. Psychoanalysis, a bridge between attachment research and neurobiology.

    Science.gov (United States)

    Rendon, Mario

    2008-06-01

    Attachment theory and neurobiology are at the forefront of scientific research, particularly in the area of child psychiatry. Several authors have encountered a surprising isomorphism between findings in these areas and concepts central in psychoanalysis. The author postulates that attachment theory is an outcome of the history of the transformation of the old concept of libido now applied interpersonally. The author also postulates that the neurobiology of attachment mediates but does not substitute psychoanalysis for the final understanding of the human bond. Findings in both fields, attachment theory and psychobiology, often compellingly lead to psychoanalytic concepts; on the other hand, the neurobiology of the psyche does not make full sense without the wealth of research conducted by psychoanalysts during the 20th century. The concept of seduction in particular, in its broad sense, is akin to mirroring and attachment and a useful tool in this regard. Although some cling to the idea of the purity of psychoanalysis and see these kin areas as a threat to its integrity, the author believes that psychoanalysis, serving as a bridge between them, can only be enriched by their empirical and experimental outcomes. The American Journal of Psychoanalysis (2008) 68, 148-155. doi:10.1057/ajp.2008.4.

  10. EVALUATION OF PHARMACIES IN ANKARA ABOUT SOME LEGAL REQUIREMENTS AND COLD CHAIN RULES

    Directory of Open Access Journals (Sweden)

    Cengiz Han ACIKEL

    Full Text Available We aimed to evaluate the pharmacies in Ankara Centrum on some legal requirements and cold chain rules. We planned this study as a cross sectional research and performed it in Ankara 15-20 June 2000. Among the 1400 registered pharmacies in Ankara, stratified sampling chose 200; 189 could be reached. A questionnaire was formed in GATA Department of Public Health to evaluate cold chain rules, and also another observation form was filled for each pharmacy. Most common faults were lack of name tags (89.4%, lack of white uniforms (70.4%, and absence of pharmacist (42.3%. 95.8% mentioned that they received unprescribed drug requests; and 69.5% confessed that they gave unprescribed drugs. 42.1% said that they had food in the refrigerators they kept vaccines and biological materials. 55.8% of the responsible personnel had no knowledge about the suitable shelve for vaccines in the refrigerator. When comparing the pharmacies according to their placement, we found that there were considerable faults and especially these were more in hospital district pharmacies. [TAF Prev Med Bull 2004; 3(7.000: 148-155

  11. High Temperature Reactions of Uranium Dioxide with Various Metal Oxides

    Science.gov (United States)

    1956-02-20

    HfO2 , 0.02 weight percent of SiO,, and not more than 0.005 weight percent of any other impurity) is reported to be 2,710°± 100 C [19, 201. Lambertson...CaO, J. Chem. Soc., p. 1352, 1151. (151 H. D. Megaw, Ferroelectricity and crystal structure, II, Acta Cryst. 1, 187 (1954). [16] W. A. Lanbertson and

  12. Pharmacokinetics of Peramivir in an Adolescent Patient Receiving Continuous Venovenous Hemodiafiltration

    OpenAIRE

    Dillon, Ryan C.; Witcher, Robert; Cies, Jeffrey J.; Moore, Wayne S.; Chopra, Arun

    2017-01-01

    Critically ill patients requiring renal replacement therapy commonly experience pharmacokinetic alterations. This case report describes the pharmacokinetics of peramivir (Rapivab, BioCryst Pharmaceuticals, Inc, Durham, NC), the first US Food and Drug Administration?approved intravenous neuraminidase inhibitor for the treatment of influenza, in an adolescent patient receiving continuous renal replacement therapy (CRRT). A 49.5-kg, 17-year-old Caucasian female presented with fever, cough, and p...

  13. Chromium isotope fractionation during coprecipitation with calcium carbonate

    DEFF Research Database (Denmark)

    Rodler, Alexandra; Sánchez-Pastor, Nuria; Fernández-Díaz, Lurdes

    The chromium (Cr) isotopic composition of carbonates can potentially be used as a paleoclimate proxy to elucidate past fluctuations of oxygen contents in atmosphere and hydrosphere. The use of Cr isotopes to track paleoenvironmental changes, for example related to the rise of oxygen during the Ar...... et al., 2007, Water Air Soil Poll. 179, 381-390. [2] Sánchez-Pastor et al., 2011, Cryst. Growth Des. 11, 3081-3089....

  14. Carbon Fiber Morphology. 2. Expanded Wide-Angle X-Ray Diffraction Studies of Carbon Fibers

    Science.gov (United States)

    1991-02-01

    X- Ray Diffraction," JPS. Polym. Phys. Ed., 16, 939 (1978). 17. Rosalind E. Franklin , "The Structure of Graphitic Carbons," Acta Cryst., 4, 253 (1951...18. Rosalind E. Franklin , "The Interpretation of Diffuse X-ray Diagrams of Carbon," Acta CrL, 3, 107 (1950). 19. K. Jain and A. S. Abhiraman...been generally mentioned much earlier by Franklin [17,18]. Jain and Abhiraman [19] demonstrated that these corrections can make significant differences

  15. Mission Support for the Communication/Navigation Outage Forecast System (C/NOFS) Satellite

    Science.gov (United States)

    2007-11-21

    applications. Acta Cryst., A52:561, 1996. [18] P. N. Guzdar, P. Satyanarayana , J. D. Huba, and S. L. Ossakow. Influence of velocity shear on Rayleigh...H. G. Mitchell, J. A. Fedder, P. Satyanarayana , S. T. Zalesak, and J. D. Huba. Nonlinear evolution of the Kelvin-Helmholtz instability in the high...1960. [52] E. E. Salpeter. Plasma density fluctuations in a magnetic field. Phys. Rev., 122:1663, 1961. [53] P. Satyanarayana , P. N. Guzdar, J. D. Huba

  16. Redetermination of tetra-kis(trimethyl-stann-yl)germane.

    Science.gov (United States)

    Bauer, Matthew; Groy, Thomas L; Kouvetakis, John

    2007-12-06

    Redetermination of the structure of the title compound, [Ge(SnMe(3))(4)] or [GeSn(4)(CH(3))(12)], previously refined from powder diffraction data only [Dinnebier, Bernatowicz, Helluy, Sebald, Wunschel, Fitch & van Smaalen et al. (2002 ▶). Acta Cryst. B58, 52-61], confirms that four bulky trimethyl-stannyl ligands surround the central Ge atom (site symmetry 1) in a tetra-hedral coordination.

  17. Triclinic polymorph of 4-[4-(4-formylphenoxybutoxy]benzaldehyde

    Directory of Open Access Journals (Sweden)

    Ivana Balić

    2013-01-01

    Full Text Available The title compound, C18H18O4, is a triclinic polymorph of the previously reported monoclinic polymorph [Han & Zhen (2005. Acta Cryst. E61, o4358–o4359]. In the crystal of the triclinic polymorph, molecules are linked by two pairs of C—H...O hydrogen bonds, forming a two-dimensional network parallel to (102, and enclosing loops with graph set motifs of R22(8 and R22(6.

  18. Chromium isotope fractionation during coprecipitation with calcium carbonate

    DEFF Research Database (Denmark)

    Rodler, Alexandra; Sánchez-Pastor, Nuria; Fernández-Díaz, Lurdes

    the Archaean and Protoerozoic, needs careful assessment of the signal robustness and necessitates a thorough understanding of the Cr cycle in Earth system processes. We conducted experiments testing the incorporation and isotopic fractionation of chromate into the calcite lattice. Our experiments indicate...... et al., 2007, Water Air Soil Poll. 179, 381-390. [2] Sánchez-Pastor et al., 2011, Cryst. Growth Des. 11, 3081-3089....

  19. Redetermination of tetra­kis(trimethyl­stann­yl)germane

    Science.gov (United States)

    Bauer, Matthew; Groy, Thomas L.; Kouvetakis, John

    2008-01-01

    Redetermination of the structure of the title compound, [Ge(SnMe3)4] or [GeSn4(CH3)12], previously refined from powder diffraction data only [Dinnebier, Bernatowicz, Helluy, Sebald, Wunschel, Fitch & van Smaalen et al. (2002 ▶). Acta Cryst. B58, 52–61], confirms that four bulky trimethyl­stannyl ligands surround the central Ge atom (site symmetry 1) in a tetra­hedral coordination. PMID:21200620

  20. Redetermination of tetrakis(trimethylstannylgermane

    Directory of Open Access Journals (Sweden)

    Matthew Bauer

    2008-01-01

    Full Text Available Redetermination of the structure of the title compound, [Ge(SnMe34] or [GeSn4(CH312], previously refined from powder diffraction data only [Dinnebier, Bernatowicz, Helluy, Sebald, Wunschel, Fitch & van Smaalen et al. (2002. Acta Cryst. B58, 52–61], confirms that four bulky trimethylstannyl ligands surround the central Ge atom (site symmetry 1 in a tetrahedral coordination.

  1. Nested sampling for materials: the case of hard spheres

    OpenAIRE

    Partay, Livia B.; Bartok, Albert P.; Csanyi, Gabor

    2012-01-01

    The recently introduced nested sampling algorithm allows the direct and efficient calculation of the partition function of atomistic systems. We demonstrate its applicability to condensed phase systems with periodic boundary conditions by studying the three dimensional hard sphere model. Having obtained the partition function, we show how easy it is to calculate the compressibility and the free energy as functions of the packing fraction and local order, verifying that the transition to cryst...

  2. From deep TLS validation to ensembles of atomic models built from elemental motions. Addenda and corrigendum.

    Science.gov (United States)

    Urzhumtsev, Alexandre; Afonine, Pavel V; Van Benschoten, Andrew H; Fraser, James S; Adams, Paul D

    2016-09-01

    Researcher feedback has indicated that in Urzhumtsev et al. [(2015) Acta Cryst. D71, 1668-1683] clarification of key parts of the algorithm for interpretation of TLS matrices in terms of elemental atomic motions and corresponding ensembles of atomic models is required. Also, it has been brought to the attention of the authors that the incorrect PDB code was reported for one of test models. These issues are addressed in this article.

  3. Itraconazol, an Antifungal and a Hedgehog Pathway Inhibitor for Treatment of Prostate Cancer

    Science.gov (United States)

    2016-10-01

    containing MTT solution [3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide] for 2 hours. Metabolically intact cells cleave tetrazolium salts... cell ith indicate 8 hours. Aft essed for ce s were l)-2,5- Metabolical uccinate- mazan cryst is the...growth and metastasis of human PCa cells representative of the advanced disease; the effect of the combination, on the growth and metastasis of human

  4. 用表面技术研究壳聚糖及其衍生物的胆甾液晶织构

    Institute of Scientific and Technical Information of China (English)

    董炎明; 吴玉松; 袁清; 阮永红; 王勉

    2000-01-01

    [1] Thomas, E. L. and Wood, B. A., Faraday Discuss. Chem. Soc., 1985, 79:229[2] Wood, B. A. and Thomas, E. L., Nature, 1986, 324:665[3] Hudson, S. D., Thomas, E. L. And Lenz, R. W., Mol. Cryst. Liq. Cryst., 1987, 153:63[4] Chen, S., Cai, L., Wu, Y., Jin Y., Zhang, S., Qing Z., Song, W. And Qian R., Kexue Tongbao, 1992, (14): 1284[5] Ford, J. R., Bassett, D. C. and Mitchell, R., Mol. Cryst. Liq. Cryst., 1990, 180B:233[6] Chen, S., Jin, Y., Hu, S. and Xu, M., Polym. Comms., 1987, (28): 209[7] Windle, A. H., Dong, Y., Lemmon, T. J. and Spontak, R. J., in Frontiers of Macromolecular Science, Ed. by Saeguas, T., Higashimura T., Abe, A., IUPAC, Blackwell, London, 1989:343[8] Tsutsui, T. and Tauaka, T., J. Polym. Sci., Polym. Lett. Ed., 1977, 15:475[9] Nishio, Y.,Yamane, T. and Takahashi, T., J. Polym.Sci., Polym. Phys. Ed., 1985, 23:1043[10] Nishio, Y., Yamane, T. and Takahashi, T., J. Polym. Sci., Polym. Phys. Ed., 1985,23:1043[11]Huang, Y., Loos, J., Yang, Y. Q. and Petermann, T., J. Polym. Sci., Polym. Phys. Ed., 1998, 36:439[12]Huang, Y., Yang, Y. Q. and Petermann, T., Polymer, 1998, 39(22):5031[13]Olley, R. H., and Bassett, D. C., Polymer, 1988, 27:344[14]Binnig, G., Quate, C. F. and Gerber, Ch., Phys. Rev. Leu., 1986, 56:930

  5. Incorporation Kinetics in Mixed Anion Compound Semiconductor Alloys

    Science.gov (United States)

    2013-01-01

    PROGRAM ELEMENT NUMBER 611102 6. AUTHORS Sd. PROJECT NUMBER Joanna M. Milhmchick, Evan M . Anderson, Chris Pearson, Wendy L. Samey, Stefan P. Svensson...Chris Pearson, Department of Computer Science, Engineering, and Physics, University of Michigan–Flint, Flint, MI 48502 Wendy L. Sarney and Stefan P...M.H. Francombe, and C.E.C. Wood , J Appl Phys 52, 7416 (1981). 27 B.W. Liang and C.W. Tu, J Cryst Growth 128, 538 (1993). 14 12 Table 1

  6. A Study of GaAsSb Nanowires by Molecular Beam Epitaxy for Near IR Applications

    Science.gov (United States)

    2015-09-18

    8), 1578–1580, 2003. 14. C. Thelander, H. A. Nilsson, L. E. Jensen, and L. Samuelson , Nano Lett. 5(4), 635–638, 2005. 15. Y. Huang, X. Duan, and C... Samuelson , and L.E. Wernersson, J. Cryst. Growth 310(18), 4115–4121, 2008. 28. A. F. Moses, T. B. Hoang, D. L. Dheeraj, H. L. Zhou, A. T. J. van Helvoort

  7. Redetermination of 1,4-dimethoxybenzene

    Directory of Open Access Journals (Sweden)

    David M. Grant

    2009-02-01

    Full Text Available The structure of the centrosymmetric title compound, C8H10O2, originally determined by Goodwin et al. [Acta Cryst.(1950, 3, 279–284], has been redetermined to modern standards of precision to aid in its use as a model compound for 13C chemical-shift tensor measurements in single-crystal NMR studies. In the crystal structure, a C—H...O interaction helps to establish the packing.

  8. a 530-590 GHZ Schottky Heterodyne Receiver for High-Resolution Molecular Spectroscopy with Lille's Fast-Scan Fully Solid-State DDS Spectrometer

    Science.gov (United States)

    Pienkina, A.; Margulès, L.; Motiyenko, R. A.; Wiedner, Martina C.; Maestrini, Alain; Defrance, Fabien

    2017-06-01

    Laboratory spectroscopy, especially at THz and mm-wave ranges require the advances in instrumentation techniques to provide high resolution of the recorded spectra with precise frequency measurement that facilitates the mathematical treatment. We report the first implementation of a Schottky heterodyne receiver, operating at room temperature and covering the range between 530 and 590 GHz, for molecular laboratory spectroscopy. A 530-590 GHz non-cryogenic Schottky solid-state receiver was designed at LERMA, Observatoire de Paris and fabricated in partnership with LPN- CNRS (Laboratoire de Photonique et de Nanostructures), and was initially developed for ESA Jupiter Icy Moons Explorer (JUICE), intended to observe Jupiter and its icy moon atmospheres. It is based on a sub-harmonic Schottky diode mixer, designed and fabricated at LERMA-LPN, pumped by a Local Oscillator (LO), consisting of a frequency Amplifier/Multiplier chains (AMCs) from RPG (Radiometer Physics GmBh). The performance of the receiver was demonstrated by absorption spectroscopy of CH_3CH_2CN with Lille's fast-scan DDS spectrometer. A series of test measurements showed the receiver's good sensitivity, stability and frequency accuracy comparable to those of 4K QMC bolometers, thus making room-temperature Schottky receiver a competitive alternative to 4K QMC bolometers to laboratory spectroscopy applications. We will present the first results with such a combination of a compact room temperature Schottky heterodyne receiver and a fast-scan DDS spectrometer. J. Treuttel, L. Gatilova, A. Maestrini et al., 2016, IEEE Trans. Terahertz Science and Tech., 6, 148-155. This work was funded by the French ANR under the Contract No. ANR-13-BS05-0008-02 IMOLABS.

  9. Molecular weight–gyration radius relation of globular proteins: a comparison of light scattering, small-angle X-ray scattering and structure-based data

    Science.gov (United States)

    Smilgies, Detlef-M.; Folta-Stogniew, Ewa

    2015-01-01

    The molecular weight–gyration radius relation for a number of globular proteins based on experimental light scattering data is compared with small-angle X-ray scattering data recently published by Mylonas & Svergun [J. Appl. Cryst. (2007 ▸), 40, s245–s249]. In addition, other recent experimental data and theoretical calculations are reviewed. It is found that the M W–R g relation for the globular proteins is well represented by a power law with an exponent of 0.37 (2). PMID:26500468

  10. Expansion Coefficient on Oxides and Oxide Ceramics.

    Science.gov (United States)

    1986-05-01

    Ferroelectrics )," Ph.D. thesis submitted to the Indian Institute of Science, Bangalore- 12, (1969). 29. B. Alefeld. "The Change of Lattice Parameters of...Kamenetskii. "Anomalous Thermal Expansion of ZrO2 and HfO2 Over the Range 20-1200 0 C," Soy. Phy.-Cryst., 14 (1970) pp. 696-99. 89. A. K. Sreedhar. "Thermal...D. Gac. "Axial and Linear Thermal Expansion of ZrO 2 and HfO2 ," Am. Ceram. Soc. RuZl. 60(4) (1981), pp. 504-506. 167. R. Ruh, G. W. Hollenberg, E

  11. NCBI nr-aa BLAST: CBRC-TBEL-01-0595 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available pdb|2I35|A Chain A, Crystal Structure Of Rhombohedral Crystal Form Of Ground- State Rhodopsin pdb|2I36|A Cha...in A, Crystal Structure Of Trigonal Crystal Form Of Ground-State Rhodopsin pdb|2I36|B Chain B, Crystal Struc...ture Of Trigonal Crystal Form Of Ground-State Rhodopsin pdb|2I36|C Chain C, Cryst...al Structure Of Trigonal Crystal Form Of Ground-State Rhodopsin pdb|2I37|A Chain A, Crystal Structure Of A P

  12. NCBI nr-aa BLAST: CBRC-BTAU-01-2416 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available pdb|2I35|A Chain A, Crystal Structure Of Rhombohedral Crystal Form Of Ground- State Rhodopsin pdb|2I36|A Cha...in A, Crystal Structure Of Trigonal Crystal Form Of Ground-State Rhodopsin pdb|2I36|B Chain B, Crystal Struc...ture Of Trigonal Crystal Form Of Ground-State Rhodopsin pdb|2I36|C Chain C, Cryst...al Structure Of Trigonal Crystal Form Of Ground-State Rhodopsin pdb|2I37|A Chain A, Crystal Structure Of A P

  13. Novel Virtual Substrates for Future Generation IR Photodetectors

    Science.gov (United States)

    2014-12-23

    substrates, J. Cryst. Growth, submitted for publication. [4] X.-H. Zhao, M.J. DiNezza, S. Liu, P.A.R.D. Jayathilaka, O.C. Noriega , T.H. Myers,, and Y.- H...Pathiraja A. R. D. Jayathilaka, Odille C. Noriega , Thomas H. Myers, and Yong-Hang Zhang, "Temperature-dependent time-resolved photoluminescence study of...X.-H Zhao, M. J. DiNezza, S. Liu, E. G. LeBlanc, P. Jayathilaka, O. C. Noriega , T. H. Myers, and Y.-H. Zhang, "CdTe/MgCdTe Double Heterostructures

  14. Atomic-Scale Imaging of Surfaces and Interfaces. Materials Research Society Symposium Proceedings Held in Boston, Massachusetts on November 30-December 2, 1992. Volume 295

    Science.gov (United States)

    1992-01-01

    51 J. J. Barton, Phys. Rev. Lett. 61, 1356 (1988) [6] S. Hardcastle, Z. -L. Han, G. R. Harp, J1. Zhang, H. L. Chen, D. K. Saldin and B. P. Tonner...Quian, Phys, Rev. B (in press). [11] W. Quian, J.C.H. Spence and J.M. Zuo, Acta Cryst. (in press). [12] G.R. Harp, D.K. Saldin , and B.P. Tonner, Phys...Lett. 67, 3102 (19--). (15] J.J. Barton, Phys. Rev. Lett. 67, 3106 (1991). [16) D.K. Saldin , G.R. Harp, B.L. Chen, and B.P. Tonner, Phys. Rev. B 44

  15. RbZnFe(PO4)2: synthesis and crystal structure

    Science.gov (United States)

    Badri, Abdessalem; Ben Amara, Mongi

    2016-01-01

    A new iron phosphate, rubidium zinc iron(III) phosphate, RbZnFe(PO4)2, has been synthesized as single crystals by the flux method. This compound is isostructural to the previously reported KCoAl(PO4)2 [Chen et al. (1997 ▸). Acta Cryst. C53,1754–1756]. Its structure consists of a three-dimensional framework built up from corner-sharing PO4 and (Zn,Fe)O4 tetra­hedra. This mode of linkage forms channels parallel to the [100], [010] and [001] directions in which the Rb+ ions are located. PMID:27536385

  16. Semiconductor Laser Diode Arrays by MOCVD (Metalorganic Chemical Vapor Deposition)

    Science.gov (United States)

    1987-09-01

    Roberts. N. J1. Mason. and M. Robinson, J. Cryst. Growth 68, 422 (1984). ’M. R. Leys. C. van Opdorp. M. P. A. .’iegers, and H. J. Talen -van der Mheen...geometry effects is and superlattices has been dominated obtained by including one measured by the MOCVD growth technology . data point in the analysis...Dapkus, Gallium : Arsenide Technology , D.K. Ferry, Ed., tices i Howard W. Sams and Co., Indianapolis, hetero- 1985, p. 79. s is nec- G . 4. G. Costrini and

  17. 3-Substituted Indole Inhibitors Against Francisella tularensis FabI Identified by Structure-Based Virtual Screening

    Science.gov (United States)

    2013-07-01

    FabI, but share low sequence identity and are poorly inhibited by triclosan.25,26 S. pneumoniae and P. aeruginosa contain FabK,24 and Vibrio cholerae ,27...Massengo-Tiasse, R. P.; Cronan, J. E. Vibrio cholerae FabV defines a new class of enoyl-acyl carrier protein reductase. J. Biol. Chem. 2008, 283, 1308...of enoyl- (acyl-carrier protein) reductase, FabV, from Vibrio fischeri. Acta Crystallogr., Sect. F: Struct. Biol. Cryst. Commun. 2012, 68, 78−80. (27

  18. An introduction to the tools hosted in the Bilbao Crystallographic Server

    Directory of Open Access Journals (Sweden)

    Aroyo M.I.

    2012-03-01

    Full Text Available The programs hosted in the Bilbao Crystallographic Server (http://www.cryst.ehu.es are briefly explained along with worked examples on various cases related to different fields of applications. It is our aim to have this text acting as a primer on the various usage of the crystallographic tools in conjunction with each other due to the modular structure of the server. For this reason, diverse topics such as crystallographic groups and their subgroups, pseudosymmetry, extinction conditions, k-vectors and irreducible representations have been discussed in the context.

  19. Redetermination of tetrakis(N,N-diethyldithiocarbamatotin(IV

    Directory of Open Access Journals (Sweden)

    Coco K. Y. A. Okio

    2009-06-01

    Full Text Available The crystal structure of the title compound, [Sn(C5H10NS24], was originally determined by Harreld & Schlemper [Acta Cryst. (1971, B27, 1964–1969] using intensity data estimated from Weissenberg films. In comparison with the previous refinement, the current redetermination reveals anisotropic displacement parameters for all non-H atoms, localization of the H atoms, and higher precision of lattice parameters and interatomic distances. The complex features a distorted S6 octahedral coordination geometry for tin and a cis disposition of the monodentate dithiocarbamate ligands.

  20. Two-dimensional motion of unstable steps induced by flow in solution

    OpenAIRE

    Sato, Masahide

    2011-01-01

    By carrying out Monte Carlo simulation, we study step instabilities during crystal growth from solution. In previous studies [M. Sato. J. Phys. Soc. Jpn. 79 (2010) 064606; M. Sato, J. Cryst. Growth 318 (2011) 5; M. Sato. J. Phys. Soc. Jpn. 80 (2011) 024604], we used a one-dimensional model, so that we were unable to study another type of instability, step wandering. In this research, we use a two-dimensional model to study both step wandering and step bunching. When the flow of solutes is in ...

  1. InxGa1-xSb Channel p-Metal-Oxide-Semiconductor Field Effect Transistors: Effect of Strain and Heterostructure Design

    Science.gov (United States)

    2011-07-06

    from 300 K to 80 K, ION increased up to 4 times due to the increase in the hole mobility, while IOFF decreased by a factor of 10 3, indi- cating a diode...N. A. Papanicolaou , and J. B. Boos, J. Cryst. Growth 312(1), 37 (2009). TABLE I. Surface roughness comparison with known values in silicon and...Bennett, N. A. Papanicolaou , M. G. Ancona, J. G. Cham- plain, R. Bass, and B. V. Shanabrook, Electron. Lett. 43, 834 (2007). 15A. Nainani, T. Irisawa, Z

  2. 3-(6-Bromo-4-oxo-4H-chromen-3-yl-3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dione

    Directory of Open Access Journals (Sweden)

    Ghulam Abbas

    2010-12-01

    Full Text Available The molecular structure of the title compound, C16H11BrN2O4S, is very similar to that of the previously reported fluoro analogue [al-Rashida et al. (2010. Acta Cryst. E66, o2707]. The mean planes of the bicyclic chromone system and the benzene ring of the benzothiadiazine derivative make a dihedral angle of 58.23 (8°. An intramolecular N—H...O hydrogen bond occurs. In the crystal, molecules are linked into layers by N—H...O and C—H...O hydrogen bonds, generating an infinite two-dimensional network.

  3. Cinchonidinium chloride monohydrate

    Directory of Open Access Journals (Sweden)

    Shi-Feng Ni

    2008-01-01

    Full Text Available In the title salt, C19H23N2O+·Cl−·H2O, the ions and the water molecule are held together by O—H...Cl, N—H...Cl, O—H...O, O—H...N and C—H...Cl hydrogen bonds, forming a three-dimensional framework. The vinyl group is disordered over two orientations with refined occupancies of 0.564 (16 and 0.436 (16. The cell parameters of the title compound have been reported previously [Griffiths (1952. Acta Cryst. 5, 290–291].

  4. Application of maximum likelihood to direct methods: the probability density function of the triple-phase sums. XI.

    Science.gov (United States)

    Rius, Jordi

    2006-09-01

    The maximum-likelihood method is applied to direct methods to derive a more general probability density function of the triple-phase sums which is capable of predicting negative values. This study also proves that maximization of the origin-free modulus sum function S yields, within the limitations imposed by the assumed approximations, the maximum-likelihood estimates of the phases. It thus represents the formal theoretical justification of the S function that was initially derived from Patterson-function arguments [Rius (1993). Acta Cryst. A49, 406-409].

  5. Patterson function and δ recycling: derivation of the phasing equations.

    Science.gov (United States)

    Rius, Jordi

    2012-05-01

    Two phasing equations based on the Fourier syntheses δ(P) = T(-1)[(E(2) - )exp(iφ)] and δ(M) = T(-1)[(E - )exp(iφ)] were recently described [Rius (2012). Acta Cryst. A 68, 77-81] (E is the quasi-normalized structure factor and is the average over all reflections). These equations were found by comparison with the direct methods origin-free modulus sum function and constitute the core of the `δ recycling' phasing procedure. The derivation of these phasing equations from the minimization of a residual (R(P)) between two differently calculated density functions (one of them including the positivity constraint) is shown.

  6. N-Methyl-N-styrylcinnamamide (lansamide from Clausena lansium in Vietnam

    Directory of Open Access Journals (Sweden)

    Peter Luger

    2009-04-01

    Full Text Available The title compound, C18H17NO, was isolated from the seeds of Clausena lansium (wampee (Rutaceae. The X-ray crystal structure analysis confirmed its chemical identity and revealed that it is solvent-free, in contrast to the previously reported monohydrate [Huang, Ou & Tang (2006. Acta Cryst. E62, o1987–o1988]. The molecular structures are practically identical but the molecules pack differently. In contrast to the monohydrate in which the water molecule generates two hydrogen bonds, no such intermolecular contacts are present in the title compound. The dihedral angle between the cinnamamide and the styryl group is 53.1 (1°.

  7. trans-Dichloridobis(triphenylphosphane-κPpalladium(II benzene hemisolvate

    Directory of Open Access Journals (Sweden)

    Frank Meyer-Wegner

    2012-04-01

    Full Text Available The title complex, [PdCl2(C18H15P2]·0.5C6H6, has the PdII ion in a square-planar coordination mode (r.m.s. deviation for Pd, P and Cl atoms = 0.024 Å with the PPh3 and Cl ligands mutually trans. The benzene solvent molecule is located about a crystallographic inversion centre. The title complex is isostructural with trans-dichloridobis(triphenylphosphanepalladium(II 1,4-dichlorobenzene sesquisolvate [Kitano et al. (1983. Acta Cryst. C39, 1015–1017].

  8. Crystal structure of hexaaquadichloridoytterbium(III chloride

    Directory of Open Access Journals (Sweden)

    Kevin M. Knopf

    2015-06-01

    Full Text Available The crystal structure of the title compound, [YbCl2(H2O6]Cl, was determined at 110 K. Samples were obtained from evaporated acetonitrile solutions containing the title compound, which consists of a [YbCl2(H2O6]+ cation and a Cl− anion. The cations in the title compound sit on a twofold axis and form O—H...Cl hydrogen bonds with the nearby Cl− anion. The coordination geometry around the metal centre forms a distorted square antiprism. The ytterbium complex is isotypic with the europium complex [Tambrornino et al. (2014. Acta Cryst. E70, i27].

  9. Crystal structure of hexa-aqua-dichlorido-ytterbium(III) chloride.

    Science.gov (United States)

    Knopf, Kevin M; Crundwell, Guy; Westcott, Barry L

    2015-06-01

    The crystal structure of the title compound, [YbCl2(H2O)6]Cl, was determined at 110 K. Samples were obtained from evaporated aceto-nitrile solutions containing the title compound, which consists of a [YbCl2(H2O)6](+) cation and a Cl(-) anion. The cations in the title compound sit on a twofold axis and form O-H⋯Cl hydrogen bonds with the nearby Cl(-) anion. The coordination geometry around the metal centre forms a distorted square anti-prism. The ytterbium complex is isotypic with the europium complex [Tambrornino et al. (2014 ▶). Acta Cryst. E70, i27].

  10. Crystal structure of benzene-1,3,5-tri-carb-oxy-lic acid-4-pyridone (1/3).

    Science.gov (United States)

    Staun, Selena L; Oliver, Allen G

    2015-11-01

    Slow co-crystallization of a solution of benzene-1,3,5-tri-carb-oxy-lic acid with a large excess of 4-hy-droxy-pyridine produces an inter-penetrating, three-dimensional, hydrogen-bonded framework consisting of three 4-pyridone and one benzene-1,3,5-tri-carb-oxy-lic acid mol-ecules, C9H6O6·3C5H5NO. This structure represents an ortho-rhom-bic polymorph of the previously reported C-centered, monoclinic structure [Campos-Gaxiola et al. (2014 ▸). Acta Cryst. E70, o453-o454].

  11. Erratum: 2-(2-Thien-yl)-4,5-dihydro-1H-imidazole. Corrigendum.

    Science.gov (United States)

    Kia, Reza; Fun, Hoong-Kun; Kargar, Hadi

    2009-05-23

    Consideration of a previous unrecognized twinning of the original investigated crystal of the title compound [Kia et al. (2009 ▶). Acta Cryst. E65, o301] led to improved reliability factors and to a slightly higher precision for all geometric parameters. The crystal under investigation was twinned by pseudo-merohedry with [100, 00, 00] as the twin matrix and a refined twin domain fraction of 0.9610 (5):0.0390 (5). The results of the new crystal structure refinement are given here.[This corrects the article DOI: 10.1107/S1600536809001068.].

  12. 2-(2-Thien­yl)-4,5-dihydro-1H-imidazole. Corrigendum

    Science.gov (United States)

    Kia, Reza; Fun, Hoong-Kun; Kargar, Hadi

    2009-01-01

    Consideration of a previous unrecognized twinning of the original investigated crystal of the title compound [Kia et al. (2009 ▶). Acta Cryst. E65, o301] led to improved reliability factors and to a slightly higher precision for all geometric parameters. The crystal under investigation was twinned by pseudo-merohedry with [100, 00, 00] as the twin matrix and a refined twin domain fraction of 0.9610 (5):0.0390 (5). The results of the new crystal structure refinement are given here. PMID:21582973

  13. Redetermination of 3-methylisoquinoline at 150 K

    Directory of Open Access Journals (Sweden)

    Andrew D. Bond

    2010-11-01

    Full Text Available The structure of the title compound, C19H9O, has been redetermined at 150 K. The redetermination is of significantly higher precision than a previous room-temperature structure [Ribar et al. (1974. Cryst. Struct. Commun. 3, 323–325]. The C—N bond lengths for this redetermination are much closer to those observed in comparable structures, and the orientation of the methyl group with respect to the isoquinoline plane is clarified. Intermolecular weak C—H...N contacts are present in the crystal.

  14. Synthesis and Thermal Behaviour of Lanthanide Complexes of 4′-[(Cholesterylox y)Carbonyl]-Benzo-15-Crown-5

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Lanthanide complexes of a steroid-substituted benzocrown ether were synthesised . The metal-to-ligand ratio of all the metal complexes is 1∶1. The ligand 4′ -[(cholesteryloxy)carbonyl]-benzo-15-crown-5 is a monotropic liquid cryst al, displaying a cholesteric mesophase. The lanthanide complexes with nitrate co unter-ions form a highly viscous mesophase, decomposing at the clearing point. The transition temperatures change as a function of the lanthanide ion. The corr esponding lanthanide complexes with dodecylsulphate (DOS) counter-ions do not f orm a mesophase. In both cases, the metal complexes have a much lower melting po int than the parent ligand.

  15. A revised version of the program VEC (visual computing in electron crystallography)

    Institute of Scientific and Technical Information of China (English)

    Li Xue-Ming; Li Fang-Hua; Fan Hai-Fu

    2009-01-01

    The program package VEC (Visual computing in Electron Crystallography) has been revised such that (i) a program converting one-line symbols to two-line symbols of (3+1)-dimensional superspace groups has been incorporated into VEC so that the latter can interpret both kinds of symbols; (ii) a bug in calculating structure factors of one-dimensionally incommensurate modulated crystals has been fixed. The correction has been verified by successfully matching the experimental electron microscopy image of an incommensurate crystal with a series of simulated images.The precompiled revised version of VEC and relevant materials are available on the Web at http://cryst.iphy.ac.cn.

  16. Molecular ordering of ethanol at the calcite surface

    DEFF Research Database (Denmark)

    Pasarín, I. S.; Yang, M.; Bovet, Nicolas Emile

    2012-01-01

    -743 ] and molecular dynamics (MD) modeling [ Yang, M., Stipp, S. L. S., and Harding, J. H.Cryst. Growth Des. 2008, 8 (11), 4066-4074 ], have suggested that OH functional groups control polysaccharide attachment. The purpose of this work was to characterize, using X-ray reflectivity (XR) combined with molecular...... dynamics (MD) simulations, the structuring on calcite of a layer of the simplest carbon chain molecule that contains an OH group, ethanol (CH 3-CH2-OH). We found evidence that EtOH forms a highly ordered structure at the calcite surface, where the first layer molecules bond with calcite. The ethanol...

  17. 3-Phenylisoxazolin-5-one: a redetermination

    Directory of Open Access Journals (Sweden)

    Abdelhanine Essaghouani

    2017-01-01

    Full Text Available The structure of the title molecule, C9H7NO2, has been redetermined to improved precision and the H atoms located [Cannas et al. (1969. Acta Cryst. B25, 1050]. The five-membered ring is almost planar (r.m.s. deviation = 0.006 Å and subtends a dihedral angle of 2.45 (6° with the benzene ring. In the crystal, molecules form ribbons running parallel to the a-axis direction through a combination of C—H...N and C—H...O hydrogen bonds. `Stair-step' offset π–π stacking interactions are also observed.

  18. Tetraammineplatinum(II dichloride ammonia tetrasolvate

    Directory of Open Access Journals (Sweden)

    Tobias Grassl

    2014-07-01

    Full Text Available The title compound, [Pt(NH34]Cl2·4NH3, was crystallized in liquid ammonia from the salt PtCl2. The platinum cation is coordinated by four ammonia molecules, forming a square-planar complex. The chloride anions are surrounded by nine ammonia molecules, either bound within the platinum complex or solvent molecules. The solvent ammonia molecules are packed in such a way that an extended network of N—H...N and N—H...Cl hydrogen bonds is formed. The structure is isotypic with [Pd(NH34]Cl2·4NH3 [Grassl & Korber (2014. Acta Cryst. E70, i32].

  19. iotbx.cif: a comprehensive CIF toolbox.

    Science.gov (United States)

    Gildea, Richard J; Bourhis, Luc J; Dolomanov, Oleg V; Grosse-Kunstleve, Ralf W; Puschmann, Horst; Adams, Paul D; Howard, Judith A K

    2011-12-01

    iotbx.cif is a new software module for the development of applications that make use of the CIF format. Comprehensive tools are provided for input, output and validation of CIFs, as well as for interconversion with high-level cctbx [Grosse-Kunstleve, Sauter, Moriarty & Adams (2002). J. Appl. Cryst.35, 126-136] crystallographic objects. The interface to the library is written in Python, whilst parsing is carried out using a compiled parser, combining the performance of a compiled language (C++) with the benefits of using an interpreted language.

  20. Electron Spin Polarization and Detection in InAs Quantum Dots Through p-Shell Trions

    Science.gov (United States)

    2010-01-08

    Kurtze, M. Bayer, S. Fafard, Z. Wasilewski , and A. Forchel, Phys. Rev. B 71, 235328 2005. 15M. E. Ware, E. A. Stinaff, D. Gammon, M. F. Doty, A. S...Potemski, S. Raymond, J. Lapointe, and Z. R. Wasilewski , Phys. Status Solidi C 3, 3748 2006. 17 I. V. Ignatiev, S. Y. Verbin, I. Y. Gerlovin, R. V...045305-5 20Z. R. Wasilewski , S. Fafard, and J. P. McCaffrey, J. Cryst. Growth 201-202, 1131 1999. 21A. Greilich, D. R. Yakovlev, A. Shabaev, A. L. Efros

  1. [Evaluation of a two-dimensional scale for the assessment of fear avoidance beliefs in elderly chronic low back pain patients].

    Science.gov (United States)

    Quint, S; Raich, M; Luckmann, J

    2011-06-01

    There is evidence on the importance of fear avoidance beliefs (FAB) as prognostic risk factors in elderly patients suffering from chronic low back pain (CLBP). However, so far there is no validated German instrument for measuring FAB in elderly CLBP patients. The aim of the study presented was to evaluate the psychometric properties of the Catastrophizing Avoidance Scale D-65+ (CAS-D-65+) within a population of elderly patients with CLBP. A cross-sectional study was conducted with measurement repeated after 4 weeks in 68 CLBP patients aged 64 years and older. The CAS-D-65+ was analyzed performing an item analysis and retest reliability. For validation standardized assessment methods (Tampa Scale of Kinesiophobia [TSK], Photography of Daily Activity - Short electronic Version [Phoda-SeV], 5-Item-FAB, pain, disability, well-being and strain) were used. Internal consistency (Cronbach's α) ranged from 0.87 to 0.92 for total scale and from 0.71 to 0.89 for the sub-scales "catastrophizing" and "avoidance", retest reliability (r(tt)) ranged from 0.67 for the sub-scale "catastrophizing" to 0.70 for total scale and sub-scale "avoidance". The CAS-D-65+ showed moderate and strong effect sizes (Cohen's d) with other related FAB scales and external criteria. As shown in this study the CAS-D-65+ is a reliable and a valid instrument for the assessment of FAB in older patients with CLBP.

  2. Crystal structure of a second triclinic polymorph of 2-methylpyridinium picrate

    Directory of Open Access Journals (Sweden)

    Jeganathan Gomathi

    2015-11-01

    Full Text Available The title molecular salt, C6H8N+·C6H2N3O7− (systematic name: 2-methylpyridinium 2,4,6-trinitrophenolate, crystallizes with two cations and two anions in the asymmetric unit. In the crystal, the cations are linked to the anions via bifurcated N—H...(O,O hydrogen bonds, generating R12(6 graph-set motifs. Numerous C—H...O hydrogen bonds are observed between these cation–anion pairs, which result in a three-dimensional network. In addition, weak aromatic π–π stacking between the 2-methylpyridinium rings [inter-centroid distance = 3.8334 (19 Å] and very weak stacking [inter-centroid distance = 4.0281 (16 Å] between inversion-related pairs of picrate anions is observed. The title salt is a second triclinic polymorph of the structure (also with Z′ = 2 reported earlier [Anita et al. (2006. Acta Cryst. C62, o567–o570; Chan et al. (2014. CrystEngComm, 16, 4508–4538]. In the title compound, the cations and anions display a chequerboard arrangement when viewed down [100], whereas in the first polymorph, (010 layers of alternating cations and anions are apparent in a [100] view. It is interesting that the unit-cell lengths are almost identical for the two polymorphs, although the inter-axial angles are quite different.

  3. The structure and refinement of apocrustacyanin C2 to 1.3 A resolution and the search for differences between this protein and the homologous apoproteins A1 and C1.

    Science.gov (United States)

    Habash, Jarjis; Helliwell, John R; Raftery, James; Cianci, Michele; Rizkallah, Pierre J; Chayen, Naomi E; Nneji, Gwen A; Zagalsky, Peter F

    2004-03-01

    The blue carotenoprotein alpha-crustacyanin of Homarus gammarus lobster carapace is comprised chemically of five 20 kDa subunits. Only two genes for the proteins have been isolated (J. B. C. Findlay, personal communication) and the five apoproteins fall into two sets of homologous proteins based on their chemical properties (CRTC, consisting of apoproteins C(1), C(2) and A(1), and CRTA, consisting of apoproteins A(2) and A(3)). The diffraction quality of apo C(2) has been improved from 2.2 to 1.3 A and its structure solved. The structure is compared with the A(1) and C(1) proteins determined at 1.4 A [Cianci et al. (2001), Acta Cryst. D57, 1219-1229] and 1.15 A, respectively [Gordon et al. (2001), Acta Cryst. D57, 1230-1237] and found to be very similar. Normalized B-factor difference plots per residue of different types were used to try to find chemically modified residues; none were found at these resolutions. It remains possible that the differences between the CRTC proteins result from differences in amidation. By comparison of a crystal grown with glycerol (studied at 1.6 A) and one grown without glycerol (studied at 1.3 A) it was seen that glycerol bound at the astaxanthin site.

  4. Orientational order parameter studies in two symmetric dimeric liquid crystals - an optical study

    Science.gov (United States)

    Pardhasaradhi, P.; Datta Prasad, P. V.; Madhavi Latha, D.; Pisipati, V. G. K. M.; Padmaja Rani, G.

    2012-12-01

    The optical technique developed by [W. Kuczynski, B. Zywucki, and J. Malecki, Determination of orientational order parameter in various liquid-crystalline phases, Mol. Cryst. Liq. Cryst. 381 (2002), pp. 1-19; B.J. Zywucki and W. Kuczynski, IEEE transactions on optical phenomena - The orientational order in nematic liquid crystals from birefringence measurements, Dielectr. Electr. Insul. 8 (2001), pp. 512-515] is fabricated and used to determine the orientational order parameter in two dimeric liquid crystalline compounds nematic and SmA phases of α,ω-bis(4-alkylanilinebenzylidene-4‧-oxy)alkane (m.OnO.m) homologous series. The compounds studied are 5.O8O.5 and 5.O10O.5 which exhibit nematic and SmA, and nematic phases, respectively. The orientational order parameter in both the phases of nematic and SmA phases of the compound one and the nematic phase of the compound two are obtained using the principle of Newton's rings which gives directly the birefringence, δn of the liquid crystal dimer. The merits of the technique used are presented over the conventional techniques for the determination of orientational order parameter. The results for the two compounds are compared with those values estimated from n e, n o and density using the two internal field models due to Vuks and Neugebauer applicable to nematic phase.

  5. Crystal structure and Hirshfeld surface analysis of 1-carb­oxy-2-(3,4-di­hydroxy­phen­yl)ethan-1-aminium chloride 2-ammonio-3-(3,4-di­hydroxy­phen­yl)propano­ate: a new polymorph of l-dopa HCl and isotypic with its bromide counterpart

    Science.gov (United States)

    Kathiravan, Perumal; Balakrishnan, Thangavelu; Venkatesan, Perumal; Ramamurthi, Kandasamy; Percino, María Judith; Thamotharan, Subbiah

    2016-01-01

    The title mol­ecular salt, C9H12NO4 +·Cl−·C9H11NO4, is isotypic with that of the bromide counterpart [Kathiravan et al. (2016 ▸). Acta Cryst. E72, 1544–1548]. The title salt is a second monoclinic polymorph of the l-dopa HCl structure reported earlier in the monoclinic space group P21 [Jandacek & Earle (1971 ▸). Acta Cryst. B27, 841–845; Mostad & Rømming (1974 ▸). Acta Chemica Scand. B28, 1161–1168]. In the title compound, monoclinic space group I2, one of the dopa mol­ecules has a positive charge with a protonated α-amino group and the α-carb­oxy­lic acid group uncharged, while the second dopa mol­ecule has a neutral charge, the α-amino group is protonated and the α-carb­oxy­lic acid is deprotonated. In the previously reported form, a single dopa mol­ecule is observed in which the α-amino group is protonated and the α-carb­oxy­lic acid group is uncharged. The invariant and variations of various types of inter­molecular inter­actions present in these two forms of dopa HCl structures are discussed with the aid of two-dimensional fingerprint plots. PMID:27840723

  6. Crystal structure and Hirshfeld surface analysis of 1-carb-oxy-2-(3,4-di-hydroxy-phen-yl)ethan-1-aminium chloride 2-ammonio-3-(3,4-di-hydroxy-phen-yl)propano-ate: a new polymorph of l-dopa HCl and isotypic with its bromide counterpart.

    Science.gov (United States)

    Kathiravan, Perumal; Balakrishnan, Thangavelu; Venkatesan, Perumal; Ramamurthi, Kandasamy; Percino, María Judith; Thamotharan, Subbiah

    2016-11-01

    The title mol-ecular salt, C9H12NO4(+)·Cl(-)·C9H11NO4, is isotypic with that of the bromide counterpart [Kathiravan et al. (2016 ▸). Acta Cryst. E72, 1544-1548]. The title salt is a second monoclinic polymorph of the l-dopa HCl structure reported earlier in the monoclinic space group P21 [Jandacek & Earle (1971 ▸). Acta Cryst. B27, 841-845; Mostad & Rømming (1974 ▸). Acta Chemica Scand. B28, 1161-1168]. In the title compound, monoclinic space group I2, one of the dopa mol-ecules has a positive charge with a protonated α-amino group and the α-carb-oxy-lic acid group uncharged, while the second dopa mol-ecule has a neutral charge, the α-amino group is protonated and the α-carb-oxy-lic acid is deprotonated. In the previously reported form, a single dopa mol-ecule is observed in which the α-amino group is protonated and the α-carb-oxy-lic acid group is uncharged. The invariant and variations of various types of inter-molecular inter-actions present in these two forms of dopa HCl structures are discussed with the aid of two-dimensional fingerprint plots.

  7. On the crystal structure of Cr2N precipitates in high-nitrogen austenitic stainless steel. III. Neutron diffraction study on the ordered Cr2N superstructure.

    Science.gov (United States)

    Lee, Tae-Ho; Kim, Sung-Joon; Shin, Eunjoo; Takaki, Setsuo

    2006-12-01

    The ordered structure of Cr(2)N precipitates in high-nitrogen austenitic steel was investigated utilizing high-resolution neutron powder diffractometry (HRPD). On the basis of the Rietveld refinement of neutron diffraction patterns, the ordered Cr2N superstructure was confirmed to be trigonal (space group P31m), with lattice parameters a=4.800 (4) and c=4.472 (5) A, as suggested in previous transmission electron microscopy studies [Lee, Oh, Han, Lee, Kim & Takaki (2005). Acta Cryst. B61, 137-144; Lee, Kim & Takaki (2006). Acta Cryst. B62, 190-196]. The occupancies of the N atoms in four crystallographic sites [1(a), 1(b), 2(d) and 2(c) Wyckoff sites] were determined to be 1.00 (5), 0.0, 0.74 (9) and 0.12 (3), respectively, reflecting a partial disordering of N atoms along the c axis. The position of the metal atom was specified to be x=0.346 (8) and z=0.244 (6), corresponding to a deviation from the ideal position (x=0.333 and z=0.250). This deviation caused the ((1/3 1/3)(0))-type superlattice reflection to appear. A comparison between the ideal and measured crystal structures of Cr2N was performed using a computer simulation of selected-area diffraction patterns.

  8. The XChemExplorer graphical workflow tool for routine or large-scale protein-ligand structure determination.

    Science.gov (United States)

    Krojer, Tobias; Talon, Romain; Pearce, Nicholas; Collins, Patrick; Douangamath, Alice; Brandao-Neto, Jose; Dias, Alexandre; Marsden, Brian; von Delft, Frank

    2017-03-01

    XChemExplorer (XCE) is a data-management and workflow tool to support large-scale simultaneous analysis of protein-ligand complexes during structure-based ligand discovery (SBLD). The user interfaces of established crystallographic software packages such as CCP4 [Winn et al. (2011), Acta Cryst. D67, 235-242] or PHENIX [Adams et al. (2010), Acta Cryst. D66, 213-221] have entrenched the paradigm that a `project' is concerned with solving one structure. This does not hold for SBLD, where many almost identical structures need to be solved and analysed quickly in one batch of work. Functionality to track progress and annotate structures is essential. XCE provides an intuitive graphical user interface which guides the user from data processing, initial map calculation, ligand identification and refinement up until data dissemination. It provides multiple entry points depending on the need of each project, enables batch processing of multiple data sets and records metadata, progress and annotations in an SQLite database. XCE is freely available and works on any Linux and Mac OS X system, and the only dependency is to have the latest version of CCP4 installed. The design and usage of this tool are described here, and its usefulness is demonstrated in the context of fragment-screening campaigns at the Diamond Light Source. It is routinely used to analyse projects comprising 1000 data sets or more, and therefore scales well to even very large ligand-design projects.

  9. Crystal structure and Hirshfeld surface analysis of 1-carboxy-2-(3,4-dihydroxyphenylethan-1-aminium chloride 2-ammonio-3-(3,4-dihydroxyphenylpropanoate: a new polymorph of l-dopa HCl and isotypic with its bromide counterpart

    Directory of Open Access Journals (Sweden)

    Perumal Kathiravan

    2016-11-01

    Full Text Available The title molecular salt, C9H12NO4+·Cl−·C9H11NO4, is isotypic with that of the bromide counterpart [Kathiravan et al. (2016. Acta Cryst. E72, 1544–1548]. The title salt is a second monoclinic polymorph of the l-dopa HCl structure reported earlier in the monoclinic space group P21 [Jandacek & Earle (1971. Acta Cryst. B27, 841–845; Mostad & Rømming (1974. Acta Chemica Scand. B28, 1161–1168]. In the title compound, monoclinic space group I2, one of the dopa molecules has a positive charge with a protonated α-amino group and the α-carboxylic acid group uncharged, while the second dopa molecule has a neutral charge, the α-amino group is protonated and the α-carboxylic acid is deprotonated. In the previously reported form, a single dopa molecule is observed in which the α-amino group is protonated and the α-carboxylic acid group is uncharged. The invariant and variations of various types of intermolecular interactions present in these two forms of dopa HCl structures are discussed with the aid of two-dimensional fingerprint plots.

  10. Acoustic waves in compressible planar layered smectic liquid crystals

    Science.gov (United States)

    Walker, A. J.; Stewart, I. W.

    2010-08-01

    A dynamic theory for compressible smectic C (SmC) liquid crystals is postulated following previous work by Leslie et al (1991 Mol. Cryst. Liq. Cryst. 198 443-54), Nakagawa (1996 J. Phys. Soc. Japan 65 100-6 2004 J. Non-Newtonian Fluid Mech. 119 123-9) and de Gennes and Prost (1993 The Physics of Liquid Crystals 2nd edn (Oxford: Oxford University Press)). This theory is then implemented with a constructed bulk elastic energy and asymmetric stress tensor to describe a system of planar layered SmC liquid crystals undergoing various modes of undulation. We show that previous work on smectic A (SmA) liquid crystals by de Gennes and Prost (1993 The Physics of Liquid Crystals 2nd edn (Oxford: Oxford University Press)) can be expanded for SmC and consolidated. Novel and confirming estimates for SmC material parameter values are produced by considering the dependence of the system on these parameters.

  11. Covariance and correlation estimation in electron-density maps.

    Science.gov (United States)

    Altomare, Angela; Cuocci, Corrado; Giacovazzo, Carmelo; Moliterni, Anna; Rizzi, Rosanna

    2012-03-01

    Quite recently two papers have been published [Giacovazzo & Mazzone (2011). Acta Cryst. A67, 210-218; Giacovazzo et al. (2011). Acta Cryst. A67, 368-382] which calculate the variance in any point of an electron-density map at any stage of the phasing process. The main aim of the papers was to associate a standard deviation to each pixel of the map, in order to obtain a better estimate of the map reliability. This paper deals with the covariance estimate between points of an electron-density map in any space group, centrosymmetric or non-centrosymmetric, no matter the correlation between the model and target structures. The aim is as follows: to verify if the electron density in one point of the map is amplified or depressed as an effect of the electron density in one or more other points of the map. High values of the covariances are usually connected with undesired features of the map. The phases are the primitive random variables of our probabilistic model; the covariance changes with the quality of the model and therefore with the quality of the phases. The conclusive formulas show that the covariance is also influenced by the Patterson map. Uncertainty on measurements may influence the covariance, particularly in the final stages of the structure refinement; a general formula is obtained taking into account both phase and measurement uncertainty, valid at any stage of the crystal structure solution.

  12. Collaborative annotation of 3D crystallographic models.

    Science.gov (United States)

    Hunter, J; Henderson, M; Khan, I

    2007-01-01

    This paper describes the AnnoCryst system-a tool that was designed to enable authenticated collaborators to share online discussions about 3D crystallographic structures through the asynchronous attachment, storage, and retrieval of annotations. Annotations are personal comments, interpretations, questions, assessments, or references that can be attached to files, data, digital objects, or Web pages. The AnnoCryst system enables annotations to be attached to 3D crystallographic models retrieved from either private local repositories (e.g., Fedora) or public online databases (e.g., Protein Data Bank or Inorganic Crystal Structure Database) via a Web browser. The system uses the Jmol plugin for viewing and manipulating the 3D crystal structures but extends Jmol by providing an additional interface through which annotations can be created, attached, stored, searched, browsed, and retrieved. The annotations are stored on a standardized Web annotation server (Annotea), which has been extended to support 3D macromolecular structures. Finally, the system is embedded within a security framework that is capable of authenticating users and restricting access only to trusted colleagues.

  13. Redetermination of Zn2Mo3O8

    Directory of Open Access Journals (Sweden)

    Jerome Cuny

    2009-07-01

    Full Text Available The crystal structure of dizinc trimolybdenum(IV octaoxide, Zn2Mo3O8, has been redetermined from single-crystal X-ray data. The structure has been reported previously based on neutron powder diffraction data [Hibble et al. (1999. Acta Cryst. B55, 683-697] and single-crystal data [McCarroll et al. (1957. J. Am. Chem. Soc. 79, 5410–5414; Ansell & Katz (1966 Acta Cryst. 21, 482–485]. The results of the current redetermination show an improvement in the precision of the structural and geometric parameters with all atoms refined with anisotropic displacement parameters. The crystal structure consists of distorted hexagonal-close-packed oxygen layers with stacking sequence abac along [001] and is held together by alternating zinc and molybdenum layers. The Zn atoms occupy both tetrahedral and octahedral interstices with a ratio of 1:1. The Mo atoms occupy octahedral sites and form strongly bonded triangular clusters involving three MoO6 octahedra that are each shared along two edges, forming a Mo3O13 unit. All atoms lie on special positions. The Zn atoms are in 2b Wyckoff positions with 3m. site symmetry, the Mo atoms are in 6c Wyckoff positions with . m. site symmetry and the O atoms are in 2a, 2b and 6c Wyckoff positions with 3m. and . m. site symmetries, respectively.

  14. Grazing-incidence small-angle X-ray scattering in a twofold rough-interface medium: a new theoretical approach using the q-eigenwave formalism.

    Science.gov (United States)

    Chukhovskii, F N; Roshchin, B S

    2015-11-01

    Based on the rigorous Green function formalism to describe the grazing-incidence small-angle X-ray scattering (GISAXS) problem, a system of two linked integral equations is derived with respect to amplitudes of the reflected and transmitted plane q-eigenwaves (eigenstate functions) propagating through two homogeneous media separated from each other by a rough surface interface. To build up the coupled solutions of these basic equations beyond the perturbation theory constraint 2kσθ0 < 1, a simple iteration procedure is proposed as opposed to the self-consistent wave approach [Chukhovskii (2011). Acta Cryst. A67, 200-209; Chukhovski (2012). Acta Cryst. A68, 505-512]. Using the first-order iteration, analytical expressions for the averaged specular and non-specular scattering intensity distributions have been obtained. These expressions are further analysed in terms of the GISAXS parameters {k, θ, θ0} and surface finish ones {σ, l, h}, where θ and θ0 are the scattering and incidence angles of the X-rays, respectively, σ is the root-mean-square roughness, l is the correlation length, h is the fractal surface model index, k = 2π/λ, and λ is the X-ray wavelength. A direct way to determine the surface finish parameters from the experimental specular and diffuse scattering indicatrix scan data is discussed for an example of GISAXS measurements from rough surfaces of α-quartz and CdTe samples.

  15. United States Air Force Summer Research Program -- 1993 Summer Research Program Final Reports. Volume 15. Wright Laboratory

    Science.gov (United States)

    1993-01-01

    illuminant, filters, and observer which are the CIE standard source D65, rugate filters, and CIE standard observer respectively. Billmeyer and Saltzman...York, 1957. 2. F. W. Billmeyer and M. Saltzman, Principles of color technology, pages 45 and 46, John Wiley and Sons, New York, 1981. 21-9 A STUDY OF

  16. Spectral data compression using weighted principal component analysis with consideration of human visual system and light sources

    Science.gov (United States)

    Cao, Qian; Wan, Xiaoxia; Li, Junfeng; Liu, Qiang; Liang, Jingxing; Li, Chan

    2016-08-01

    This paper proposed two weight functions based on principal component analysis (PCA) to reserve more colorimetric information in spectral data compression process. One weight function consisted of the CIE XYZ color-matching functions representing the characteristic of the human visual system, while another was made up of the CIE XYZ color-matching functions of human visual system and relative spectral power distribution of the CIE standard illuminant D65. The improvement obtained from the proposed two methods were tested to compress and reconstruct the reflectance spectra of 1600 glossy Munsell color chips and 1950 Natural Color System color chips as well as six multispectral images. The performance was evaluated by the mean values of color difference under the CIE 1931 standard colorimetric observer and the CIE standard illuminant D65 and A. The mean values of root mean square errors between the original and reconstructed spectra were also calculated. The experimental results show that the proposed two methods significantly outperform the standard PCA and another two weighted PCA in the aspects of colorimetric reconstruction accuracy with very slight degradation in spectral reconstruction accuracy. In addition, weight functions with the CIE standard illuminant D65 can improve the colorimetric reconstruction accuracy compared to weight functions without the CIE standard illuminant D65.

  17. Spectral data compression using weighted principal component analysis with consideration of human visual system and light sources

    Science.gov (United States)

    Cao, Qian; Wan, Xiaoxia; Li, Junfeng; Liu, Qiang; Liang, Jingxing; Li, Chan

    2016-10-01

    This paper proposed two weight functions based on principal component analysis (PCA) to reserve more colorimetric information in spectral data compression process. One weight function consisted of the CIE XYZ color-matching functions representing the characteristic of the human visual system, while another was made up of the CIE XYZ color-matching functions of human visual system and relative spectral power distribution of the CIE standard illuminant D65. The improvement obtained from the proposed two methods were tested to compress and reconstruct the reflectance spectra of 1600 glossy Munsell color chips and 1950 Natural Color System color chips as well as six multispectral images. The performance was evaluated by the mean values of color difference under the CIE 1931 standard colorimetric observer and the CIE standard illuminant D65 and A. The mean values of root mean square errors between the original and reconstructed spectra were also calculated. The experimental results show that the proposed two methods significantly outperform the standard PCA and another two weighted PCA in the aspects of colorimetric reconstruction accuracy with very slight degradation in spectral reconstruction accuracy. In addition, weight functions with the CIE standard illuminant D65 can improve the colorimetric reconstruction accuracy compared to weight functions without the CIE standard illuminant D65.

  18. Comment on "Protonium annihilation into $\\pi^{0} \\pi^{0}$ at rest in a liquid hydrogen target"

    CERN Document Server

    Amsler, Claude; Barnett, B M; Batty, C J; Benayoun, M; Blüm, P; Braune, K; Bugg, D V; Case, T; Credé, V; Crowe, K M; Doser, Michael; Dünnweber, W; Engelhardt, D; Faessler, M A; Haddock, R P; Heinsius, F H; Heinzelmann, M; Hessey, N P; Hidas, P; Jamnik, D; Kalinowsky, H; Kammel, P; Kisiel, J; Klempt, E; Koch, H; Kunze, M; Kurilla, U; Landua, Rolf; Matthäy, H; Meyer, C A; Meyer-Wildhagen, F; Ouared, R; Peters, K; Pick, B; Ratajczak, M; Regenfus, C; Reinnarth, J; Röthel, W; Sarantsev, A V; Spanier, S; Strohbusch, U; Suffert, Martin; Suh, J S; Thoma, U; Uman, I; Wallis-Plachner, S; Walther, D; Wiedner, U; Wittmack, K; Zou, B S

    2002-01-01

    We comment on the recent paper published by the Obelix Collaboration on protonium annihilation into pi /sup 0/ pi /sup 0/ at rest in a liquid hydrogen target ÝPhys. Rev. D 65, 012001 (2002)¿, with particular reference to the discrepancy with the results obtained by the Crystal Barrel Collaboration.

  19. PENGARUH FRAKSI AIR EKSTRAK BAWANG PUTIH TERHADAP KADAR KALIUM IODAT DALAM GARAM BERIODIUM

    Directory of Open Access Journals (Sweden)

    Komari Komari

    2012-11-01

    Gizi Makan 2009, 32(2: 148-155]   Key words: fortified salt, potassium iodine, garlic, extracts

  20. High-resolution structure of human carbonic anhydrase II complexed with acetazolamide reveals insights into inhibitor drug design.

    Science.gov (United States)

    Sippel, Katherine H; Robbins, Arthur H; Domsic, John; Genis, Caroli; Agbandje-McKenna, Mavis; McKenna, Robert

    2009-10-01

    The crystal structure of human carbonic anhydrase II (CA II) complexed with the inhibitor acetazolamide (AZM) has been determined at 1.1 A resolution and refined to an R(cryst) of 11.2% and an R(free) of 14.7%. As observed in previous CA II-inhibitor complexes, AZM binds directly to the zinc and makes several key interactions with active-site residues. The high-resolution data also showed a glycerol molecule adjacent to the AZM in the active site and two additional AZMs that are adventitiously bound on the surface of the enzyme. The co-binding of AZM and glycerol in the active site demonstrate that given an appropriate ring orientation and substituents, an isozyme-specific CA inhibitor may be developed.

  1. An alternative empirical model for the relationship between the bond valence and the thermal expansion rate of chemical bonds.

    Science.gov (United States)

    Sidey, Vasyl

    2015-08-01

    The relationship between the bond valence s and the thermal expansion rate of chemical bonds (dr/dT) has been closely approximated by using the alternative three-parameter empirical model (dr/dT) = (u + vs)(-1/w), where u, v and w are the refinable parameters. Unlike the s-(dr/dT) model developed by Brown et al. [(1997), Acta Cryst. B53, 750-761], this alternative model can be optimized for particular s-(dr/dT) datasets in the least-squares refinement procedure. For routine calculations of the thermal expansion rates of chemical bonds, the alternative model with the parameters u = -63.9, v = 2581.0 and w = 0.647 can be recommended.

  2. A monoclinic polymorph of 1,2-bis[(1-methyl-1H-tetrazol-5-ylsulfanyl]ethane (BMTTE

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    Saray Argibay-Otero

    2017-10-01

    Full Text Available The synthesis and crystal structure of a monoclinic (P21/c polymorph of the title compound, C6H10S2N8, are reported. The molecule has pseudo-twofold rotational symmetry, with the tetrazole rings being inclined to one another by 5.50 (6°. In the crystal, molecules are linked by C—H...N hydrogen bonds, forming chains propagating along [101] and enclosing R22(20 ring motifs. The chains are linked by offset π–π interactions involving the tetrazole rings [intercentroid distances vary from 3.3567 (7 to 3.4227 (7 Å], forming layers parallel to the ac plane. The crystal structure of the triclinic polymorph (P\\overline{1} has been described previously [Li et al. (2011. Acta Cryst. E67, o1669].

  3. Diosgenin hemihydrate

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    María-Guadalupe Hernández Linares

    2012-08-01

    Full Text Available Diosgenin [or (22R,25R-spirost-5-en-3β-ol] is the starting material of the Marker degradation, a cheap semi-synthesis of progesterone, which has been designated as an International Historic Chemical Landmark. Thus far, a single X-ray structure for diosgenin is known, namely its dimethyl sulfoxide solvate [Zhang et al. (2005. Acta Cryst. E61, o2324–o2325]. We have now determined the structure of the hemihydrate, C27H42O3·0.5H2O. The asymmetric unit contains two diosgenin molecules, with quite similar conformations, and one water molecule. Hydroxy groups in steroids and water molecules form O—H...O hydrogen-bonded R54(10 ring motifs. Fused edge-sharing R(10 rings form a backbone oriented along [100], which aggregates the diosgenin molecules in the crystal structure.

  4. Potassium tetracyanidoaurate(III monohydrate: a redetermination

    Directory of Open Access Journals (Sweden)

    Nobuyuki Matsushita

    2017-03-01

    Full Text Available The structure of the title metal complex salt, K[Au(CN4]·H2O, has been redetermined using X-ray diffraction data at 173 K in order to improve the precision. The previous determination was based on neutron diffraction data [Bertinotti & Bertinotti (1970. Acta Cryst. B26, 422–428]. The title compound crystallizes in the space group P212121 with one potassium cation, one [Au(CN4]− anion and one water molecule in the asymmetric unit. The AuIII atom lies on a general position and has an almost square-planar coordination sphere defined by four cyanide ligands. Interactions between the potassium cation and N atoms of the complex anion, as well as O—H...N hydrogen bonds, lead to the formation of a three-dimensional framework structure.

  5. Quench-in of different high T complexities of glassformers for leisurely study at lower temperatures

    DEFF Research Database (Denmark)

    Angell, C. A.; Yue, Yuanzheng; Wang, L. M.

    Quenching-in of different high T complexities of glassformers for leisurely study at lower temperatures We describe a series of experiments on glass-forming liquids that are motivated by a common idea. The idea is that of trapping in a high enthalpy, high entropy, and state of the system...... from that at constant volume. For glassformers that can exhibit liquid-liquid transitions, one can use the cold equilibration approach to determine the fragility of the high temperature phase, and the enthalpy of the liquid-liquid transition, see ref.2. References. 1. C. A. Angell, Yuanzheng Yue, Limin...... Wang, John R. D. Copley, Steve Borick and Stefano Mossa. J. Phys. Cond Matt 15, S1051-S1068 (2003) 2. M. C. Wilding, P. F. McMillan, Polyamorphic transitions in yttria-alumina liquids, J. Non-Cryst. Solids 293, 357 (2001)....

  6. Exact conditional distribution of a three-phase invariant in the space group P1. I. Derivation and simplification of the Fourier series.

    Science.gov (United States)

    Shmueli, U; Rabinovich, S; Weiss, G H

    1989-06-01

    An exact expression is derived for the conditional probability density function of a three-phase invariant and the general result is applied to the space group P1. The expression for the conditional density is given in terms of a sixfold Fourier series. A straightforward numerical evaluation of this series, without further analysis, is extremely time consuming. Much of the present paper is therefore devoted to an exposition of symmetries hidden in the various summations. The computational effort required for the evaluation of the above expression is thereby reduced to manageable proportions in a number of interesting cases. Results of numerical computations of the exact conditional density are given in the second paper in this series. It is also shown that the exact expression for the conditional probability reduces to that given by Cochran [Acta Cryst. (1955), 8, 473-478].

  7. Crystal structure of bis-[tetra-kis-(tri-phenyl-phosphane-κP)silver(I)] (nitrilo-tri-acetato-κ(4) N,O,O',O'')(tri-phenyl-phosphane-κP)argentate(I) with an unknown amount of methanol as solvate.

    Science.gov (United States)

    Noll, Julian; Korb, Marcus; Lang, Heinrich

    2016-03-01

    The structure of the title compound, [Ag(C18H15P)4]2[Ag(C6H6NO6)(C18H15P)], exhibits trigonal (P-3) symmetry, with a C 3 axis through all three complex ions, resulting in an asymmetric unit that contains one third of the atoms present in the formula unit. The formula unit thus contains two of the cations, one anion and disordered mol-ecules of methanol as the packing solvent. Attempts to refine the solvent model were unsuccessful, indicating uninter-pretable disorder. Thus, the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18] was applied, accounting for 670 electrons per unit cell, representing approximately 18 mol-ecules of methanol in the formula unit. The stated crystal data for M r, μ etc do not take these into account.

  8. RIBFIND: a web server for identifying rigid bodies in protein structures and to aid flexible fitting into cryo EM maps.

    Science.gov (United States)

    Pandurangan, Arun Prasad; Topf, Maya

    2012-09-15

    To better analyze low-resolution cryo electron microscopy maps of macromolecular assemblies, component atomic structures frequently have to be flexibly fitted into them. Reaching an optimal fit and preventing the fitting process from getting trapped in local minima can be significantly improved by identifying appropriate rigid bodies (RBs) in the fitted component. Here we present the RIBFIND server, a tool for identifying RBs in protein structures. The server identifies RBs in proteins by calculating spatial proximity between their secondary structural elements. The RIBFIND web server and its standalone program are available at http://ribfind.ismb.lon.ac.uk. a.pandurangan@mail.cryst.bbk.ac.uk Supplementary data are available at Bioinformatics online.

  9. Dimethyl 2,2′-[(4-oxo-2-phenyl-4H-chromene-5,7-diyldioxy]diacetate: a less densely packed polymorph

    Directory of Open Access Journals (Sweden)

    Nagarajan Sulochana

    2009-02-01

    Full Text Available The title molecule, C21H18O8, crystallizes in two crystal polymorphs, see also Nallasivam, Nethaji, Vembu & Jaswant [Acta Cryst. (2009, E65, o312–o313]. The main difference between the two polymorphs is in the conformation of the oxomethylacetate groups with regard to the almost planar [total puckering amplitude 0.047 (2 Å] chromene ring. In the title compound, the best planes of the oxomethylacetate groups through the non-H atoms are almost perpendicular to the chromene ring [making dihedral angles of 89.61 (6 and 80.59 (5°], while in the second polymorph the molecules are close to planar. Both crystal structures are stabilized by C—H...O.

  10. GPCRTree: online hierarchical classification of GPCR function

    Directory of Open Access Journals (Sweden)

    Timmis Jon

    2008-08-01

    Full Text Available Abstract Background G protein-coupled receptors (GPCRs play important physiological roles transducing extracellular signals into intracellular responses. Approximately 50% of all marketed drugs target a GPCR. There remains considerable interest in effectively predicting the function of a GPCR from its primary sequence. Findings Using techniques drawn from data mining and proteochemometrics, an alignment-free approach to GPCR classification has been devised. It uses a simple representation of a protein's physical properties. GPCRTree, a publicly-available internet server, implements an algorithm that classifies GPCRs at the class, sub-family and sub-subfamily level. Conclusion A selective top-down classifier was developed which assigns sequences within a GPCR hierarchy. Compared to other publicly available GPCR prediction servers, GPCRTree is considerably more accurate at every level of classification. The server has been available online since March 2008 at URL: http://igrid-ext.cryst.bbk.ac.uk/gpcrtree/.

  11. 1-(Prop-2-ynylindoline-2,3-dione

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    Fatima-Zahrae Qachchachi

    2014-03-01

    Full Text Available The structure of the title compound, C11H7NO2, is isotypic to that of its homologue, 1-octylindoline-2,3-dione [Qachchachi et al. (2013. Acta Cryst. E69, o1801]. The indoline ring and the two carbonyl O atoms are approximately coplanar, the largest deviation from the mean plane being 0.021 (1 Å for one of the O atoms. The mean plane through the fused ring system is nearly perpendicular to the propynyl group, as indicated by the N—C—C—C torsion angle of 77.9 (1°. In the crystal, molecules are linked by C—H...O hydrogen bonds and π–π interactions between benzene rings [intercentroid distance = 3.5630 (10 Å], forming a three-dimensional structure.

  12. A new polymorph of N-(2-{N′-[(1E-2-hydroxybenzylidene]hydrazinecarbonyl}phenylbenzamide

    Directory of Open Access Journals (Sweden)

    Shaaban K. Mohamed

    2014-06-01

    Full Text Available The title compound, C21H17N3O3, is a new polymorph of an already published structure [Shashidhar et al. (2006. Acta Cryst. E62, o4473–o4475]. The previously reported structure crystallizes in the monoclinic space group C2/c, whereas the structure reported here is in the tetragonal space group I41/a. The bond lengths and angles are similar in both structures. The molecule adopts an extended conformation via intramolecular N—H...O and O—H...N hydrogen bonds; the terminal phenyl ring and the hydroxylphenyl ring are twisted with respect to the central benzene ring by 44.43 (7 and 21.99 (8°, respectively. In the crystal, molecules are linked by N—H...O hydrogen bonds, weak C—H...O hydrogen bonds and weak C—H...π interactions into a three-dimensional supramolecular network.

  13. Crystal structure of bis(2-amino-5-chloropyridinium tetrachloridocobaltate(II

    Directory of Open Access Journals (Sweden)

    Marwa Mghandef

    2015-05-01

    Full Text Available The title salt, (C5H6ClN22[CoCl4], was synthesized by slow evaporation of an aqueous solution at room temperature. The asymmetric unit consists of two essentially planar (C5H6ClN2+ cations [maximum deviations = 0.010 (3 and 0.014 (3 Å] that are nearly perpendicular to each other [dihedral angle = 84.12 (7°]. They are bonded through N—H...Cl hydrogen bonds to distorted [CoCl4]2− tetrahedra, leading to the formation of undulating layers parallel to (100. The structure is isotypic with the Zn analogue [Kefi et. al (2011. Acta Cryst. E67, m355–m356.

  14. Redetermination of [Pr(NO33(H2O4]·2H2O

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    Roel Decadt

    2012-07-01

    Full Text Available The structure of the title compound, tetraaquatris(nitrato-κ2O,O′praseodymium(III dihydrate, was redetermined. The structure models derived from the previous determinations [Rumanova et al. (1964. Kristallografiya, 9, 642–654; Fuller & Jacobson (1976. Cryst. Struct. Commun. 5, 349–352] were confirmed, but now with all H atoms unambiguously located, revealing a complex O—H...O hydrogen-bonding network, extending throughout the whole structure. In the title compound, the coordination environment of the PrIII atom can best be described as a distorted bicapped square antiprism defined by three bidentate nitrate anions and four water molecules. Additionally, two lattice water molecules are observed in the crystal packing. The title compound is isotypic with several other lanthanide-containing nitrate analogues.

  15. On the correlation between hydrogen bonding and melting points in the inositols

    DEFF Research Database (Denmark)

    Bekö, Sándor L; Alig, Edith; Schmidt, Martin U;

    2014-01-01

    Inositol, 1,2,3,4,5,6-hexahydroxycyclohexane, exists in nine stereoisomers with different crystal structures and melting points. In a previous paper on the relationship between the melting points of the inositols and the hydrogen-bonding patterns in their crystal structures [Simperler et al. (2006...... ▶). CrystEngComm 8, 589], it was noted that although all inositol crystal structures known at that time contained 12 hydrogen bonds per molecule, their melting points span a large range of about 170 °C. Our preliminary investigations suggested that the highest melting point must be corrected for the effect...... of molecular symmetry, and that the three lowest melting points may need to be revised. This prompted a full investigation, with additional experiments on six of the nine inositols. Thirteen new phases were discovered; for all of these their crystal structures were examined. The crystal structures of eight...

  16. Redetermination of the borax structure from laboratory X-ray data at 145 K

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    Caleb Higham

    2008-05-01

    Full Text Available The title compound, sodium tetraborate decahydrate (mineral name: borax, Na2[B4O5(OH4]·8H2O, has been studied previously using X-ray [Morimoto (1956. Miner. J. 2, 1–18] and neutron [Levy & Lisensky (1978. Acta Cryst. B34, 3502–3510] diffraction data. The structure contains tetraborate anions [B4O5(OH4]2− with twofold rotation symmetry, which form hydrogen-bonded chains, and [Na(H2O6] octahedra that form zigzag chains [Na(H2O4/2(H2O2/1]. The O—H bond distances obtained from the present redetermination at 145 K are shorter than those in the neutron study by an average of 0.127 (19 Å.

  17. Structure of Physarum polycephalum cytochrome b5 reductase at 1.56 A resolution.

    Science.gov (United States)

    Kim, Sangwoo; Suga, Michihiro; Ogasahara, Kyoko; Ikegami, Terumi; Minami, Yoshiko; Yubisui, Toshitsugu; Tsukihara, Tomitake

    2007-04-01

    Physarum polycephalum cytochrome b(5) reductase catalyzes the reduction of cytochrome b(5) by NADH. The structure of P. polycephalum cytochrome b(5) reductase was determined at a resolution of 1.56 A. The molecular structure was compared with that of human cytochrome b(5) reductase, which had previously been determined at 1.75 A resolution [Bando et al. (2004), Acta Cryst. D60, 1929-1934]. The high-resolution structure revealed conformational differences between the two enzymes in the adenosine moiety of the FAD, the lid region and the linker region. The structural properties of both proteins were inspected in terms of hydrogen bonding, ion pairs, accessible surface area and cavity volume. The differences in these structural properties between the two proteins were consistent with estimates of their thermostabilities obtained from differential scanning calorimetry data.

  18. Aripiprazole salts. II. Aripiprazole perchlorate.

    Science.gov (United States)

    Freire, Eleonora; Polla, Griselda; Baggio, Ricardo

    2012-06-01

    The molecular structure of aripiprazole perchlorate (systematic name: 4-(2,3-dichlorophenyl)-1-{4-[(2-oxo-1,2,3,4-tetrahydroquinolin-7-yl)oxy]butyl}piperazin-1-ium perchlorate), C(23)H(28)Cl(2)N(3)O(2)(+)·ClO(4)(-), does not differ substantially from the recently published structure of aripiprazole nitrate [Freire, Polla & Baggio (2012). Acta Cryst. C68, o170-o173]. Both compounds have almost identical bond distances, bond angles and torsion angles. The two different counter-ions occupy equivalent places in the two structures, giving rise to very similar first-order `packing motifs'. However, these elemental arrangements interact with each other in different ways in the two structures, leading to two-dimensional arrays with quite different organizations.

  19. A triclinic polymorph of (-)-(S)-N-benzyl-2-[(R)-6-fluoro-chroman-2-yl]-2-hy-droxy-ethanaminium bromide.

    Science.gov (United States)

    Rousselin, Yoann; Laureano, Hugo; Clavel, Alexandre

    2013-12-01

    The title salt, C18H21FNO2 (+)·Br(-), determined at 115 K, crystallizes in the triclinic space group P1. The previously reported polymorph occurs in the monoclinic space group P21 and has two independent mol-ecules in the asymmetric unit [Peeters et al. (1993 ▶). Acta Cryst. C49, 2157-2160]. In the title molecule, the pyran rings adopt half-chair conformations. The absolute configuration is S for the hy-droxy-bearing C atom and R for the asymmetric C atom in the di-hydro-pyran unit. In the crystal, the components are linked by N-H⋯Br and O-H⋯Br hydrogen bonds, forming chains along the c-axis direction. The crystal studied was refined as an inversion twin.

  20. (η2,η2-Cycloocta-1,5-diene[2-(diphenylphosphanylmethylpyridine-κ2N,P]rhodium(I tetrafluoridoborate 1,2-dichloroethane monosolvate

    Directory of Open Access Journals (Sweden)

    Siping Wei

    2016-08-01

    Full Text Available The title compound, [Rh(C8H12(C18H16NP]BF4 has been prepared as a precatalyst for applications in rhodium-catalysed additions of carbocyclic acids to terminal alkynes leading to anti-Markovnikov Z-enol esters. Here the triclinic pseudopolymorph of the title compound is presented. In contrast to the earlier reported pseudopolymorph (orthorhombic space group [Wei et al. (2013. Chem. Eur. J. 19, 12067–12076], the triclinic polymorph contains half a molecule of dichloromethane as solvent in the asymmetric unit. The rhodium(I atom exhibits a square-planar coordination. The estimated diffraction contribution of the disordered solvent (a half molecule of dichloroethane per asymmetric unit was subtracted from the observed diffraction data using the SQUEEZE [Spek (2015. Acta Cryst. C71, 9–16] routine in PLATON. The given chemical formula and other crystal data do not take the solvent into account.

  1. Simulations of Kikuchi patterns due to thermal diffuse scattering on MgO crystals.

    Science.gov (United States)

    Omoto, Kazuya; Tsuda, Kenji; Tanaka, Michiyoshi

    2002-01-01

    Inelastic scattering of fast transmission electrons from a perfect crystal is investigated using the Bloch wave theory. A comprehensive expression for the scattering of electrons is given, which includes both elastic and inelastic multiple scatterings. This expression is an extended form of Fujimoto's expression for elastic scattering (J. Phys. Soc. Japan 14:1558 (1959)). For the approximation of single inelastic scattering, the expression becomes equivalent to the formula of Rez et al. (Phil. Mag. 35: 81 (1977)). When thermal diffuse scattering (TDS) is considered using the Einstein model or the scattering factor for TDS given by Hall and Hirsch (Proc. R. Soc. A 286: 158 (1965)), Rossouw and Bursill's expression (Acta Cryst. A 41: 320 (1985)) is derived. This expression has been used in computer simulations of TDS intensity distribution (Kikuchi pattern). It is shown that the simulations for magnesium oxide (MgO) using 357 beams agree quite well with the experimental ones.

  2. A New, More Stable Polymorphic Form of Otilonium Bromide: Solubility, Crystal Structure, and Phase Transformation.

    Science.gov (United States)

    Vega, Daniel R; Halac, Emilia; Segovia, Luciano; Baggio, Ricardo

    2016-10-01

    A new polymorphic form of otilonium bromide is presented (Form I), and a thorough analysis of its crystal and molecular structure is performed. The compound suffers a temperature-driven first-order phase transition at about 396 K, which transforms it into the polymorph reported by Dapporto P and Sega A (Acta Cryst. 1986;C42:474-478) (Form II). Through thermal analysis and solubility experiments the relative stability of both crystal modifications were determined, confirming that at room temperature this new Form I is the more stable one, Form II existing just in a metastable state. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  3. Triclinic modification of N-[(1,1-dimethylethoxycarbonyl]-3-[(R-prop-2-en-1-ylsulfinyl]-(R-alanine ethyl ester at 120 (1 K

    Directory of Open Access Journals (Sweden)

    Suneel P. Singh

    2009-06-01

    Full Text Available There are two independent molecules in the asymmetric unit of the title compound, C13H23NO5S. In the crystal structure, intermolecular N—H...O hydrogen bonds link molecules into two independent one-dimensional chains along [100]. The crystal studied was found to be a non-merohedral twin with a ratio of 0.615 (6:0.385 (1 for the refined components. At 200 (1 K [Singh et al. (2009. Acta Cryst. E65, o1385–o1386] the crystal structure of the title compound contains one disordered molecule in the asymmetric unit of a monoclinic unit cell.

  4. SPEDEN: Reconstructing single particles from their diffraction patterns

    CERN Document Server

    Hau-Riege, S P; Chapman, H N; Szoke, A; Marchesini, S; Noy, A; He, H; Howells, M R; Weierstall, U; Spence, J C H

    2004-01-01

    Speden is a computer program that reconstructs the electron density of single particles from their x-ray diffraction patterns, using a single-particle adaptation of the Holographic Method in crystallography. (Szoke, A., Szoke, H., and Somoza, J.R., 1997. Acta Cryst. A53, 291-313.) The method, like its parent, is unique that it does not rely on ``back'' transformation from the diffraction pattern into real space and on interpolation within measured data. It is designed to deal successfully with sparse, irregular, incomplete and noisy data. It is also designed to use prior information for ensuring sensible results and for reliable convergence. This article describes the theoretical basis for the reconstruction algorithm, its implementation and quantitative results of tests on synthetic and experimentally obtained data. The program could be used for determining the structure of radiation tolerant samples and, eventually, of large biological molecular structures without the need for crystallization.

  5. Extending the S-FFT direct-methods algorithm to density functions with positive and negative peaks. XIV.

    Science.gov (United States)

    Rius, Jordi; Frontera, Carles

    2008-11-01

    Some years ago the direct-methods origin-free modulus sum function (S) was adapted to the processing of intensity data from density functions with positive and negative peaks [Rius, Miravitlles & Allmann (1996). Acta Cryst. A52, 634-639]. That implementation used phase relationships explicitly. Although successfully applied to different situations where the number of reflections was small, its generalization to larger problems required avoiding the time-consuming manipulation of quartet terms. To circumvent this limitation, a modification of the recently introduced S-FFT algorithm (that maximizes S with only Fourier transforms) is presented here. The resulting S2-FFT algorithm is highly effective for crystal structures with at least one moderate scatterer in the unit cell. Test calculations have been performed on conventional single-crystal X-ray diffraction data, on neutron diffraction data of compounds with negative scatterers and on intensities of superstructure reflections to solve difference structures.

  6. Improving the direct-methods sign-unconstrained S-FFT algorithm. XV.

    Science.gov (United States)

    Rius, Jordi; Frontera, Carles

    2009-11-01

    In order to extend the application field of the direct-methods S-FFT phase-refinement algorithm to density functions with positive and negative peaks, the equal-sign constraint was removed from its definition by combining rho(2) with an appropriate density function mask [Rius & Frontera (2008). Acta Cryst. A64, 670-674]. This generalized algorithm (S(2)-FFT) was shown to be highly effective for crystal structures with at least one moderate scatterer in the unit cell but less effective when applied to structures with only light scatterers. To increase the success rate in this second case, the mask has been improved and the convergence rate of S(2)-FFT has been investigated. Finally, a closely related but simpler phase-refinement function (S(m)) combining rho (instead of rho(2)) with a new mask is introduced. For simple cases at least this can also treat density peaks in the absence of the equal-sign constraint.

  7. A direct phasing method based on the origin-free modulus sum function and the FFT algorithm. XII.

    Science.gov (United States)

    Rius, Jordi; Crespi, Anna; Torrelles, Xavier

    2007-03-01

    An alternative way of refining phases with the origin-free modulus sum function S is shown that, instead of applying the tangent formula in sequential mode [Rius (1993). Acta Cryst. A49, 406-409], applies it in parallel mode with the help of the fast Fourier transform (FFT) algorithm. The test calculations performed on intensity data of small crystal structures at atomic resolution prove the convergence and hence the viability of the procedure. This new procedure called S-FFT is valid for all space groups and especially competitive for low-symmetry ones. It works well when the charge-density peaks in the crystal structure have the same sign, i.e. either positive or negative.

  8. Acanthamoeba polyphaga mimivirus NDK: preliminary crystallographic analysis of the first viral nucleoside diphosphate kinase.

    Science.gov (United States)

    Jeudy, Sandra; Coutard, Bruno; Lebrun, Régine; Abergel, Chantal

    2005-06-01

    The complete sequence of the largest known double-stranded DNA virus, Acanthamoeba polyphaga mimivirus, has recently been determined [Raoult et al. (2004), Science, 306, 1344-1350] and revealed numerous genes not expected to be found in a virus. A comprehensive structural and functional study of these gene products was initiated [Abergel et al. (2005), Acta Cryst. F61, 212-215] both to better understand their role in the virus physiology and to obtain some clues to the origin of DNA viruses. Here, the preliminary crystallographic analysis of the viral nucleoside diphosphate kinase protein is reported. The crystal belongs to the cubic space group P2(1)3, with unit-cell parameter 99.425 A. The self-rotation function confirms that there are two monomers per asymmetric unit related by a twofold non-crystallographic axis and that the unit cell thus contains four biological entities.

  9. Redetermination of 5α-androstane-3,17-dione

    Directory of Open Access Journals (Sweden)

    Jerry P. Jasinski

    2010-06-01

    Full Text Available The structure of the title compound, C19H28O2, has been redermined at 295 (2 K, with much improved precision. The structure and molecular packing of the title compound was first reported by Coiro et al. [Acta Cryst. (1973. B29, 1404–1409] by means of potential-energy calculations. The cell parameters in this study differ considerably in space group C2. It is a derivative of testosterone and consists of a cyclopentanone ring (A fused to to successive cyclohexane (B and C and cyclohexanone (D rings. The three cyclohexanone rings are in slightly distorted boat configurations and the cyclopentanone ring is a distorted half-chair. The crystal packing is stabilized by weak intermolecular C—H...O interactions involving O atoms from each of the cyclohexanone and cyclopentanone rings and H atoms from each of their respective rings.

  10. A monoclinic polymorph of (R,R-4,4′-dibromo-2,2′-[cyclohexane-1,2-diylbis(nitrilomethanylylidene]diphenol

    Directory of Open Access Journals (Sweden)

    Kwang Ha

    2012-05-01

    Full Text Available The title compound, C20H20Br2N2O2, a tetradentate Schiff base, is the enantiomerically pure R,R-diastereomer of four possible stereoisomers. The molecular structure reveals two strong intramolecular O—H...N hydrogen bonds between the hydroxy O atom and the imino N atom, which each generate S(6 rings. In the crystal, molecules are stacked in columns along the a axis; when viewed down the b axis, successive columns are stacked in the opposite direction. The structure reported herein is the monoclinic polymorph of the previously reported orthorhombic form [Yi & Hu (2009. Acta Cryst. E65, o2643], in which the complete molecule is generated by a crystallographic twofold axis.

  11. Tris{2-methoxy-6-[(4-methylphenyliminiomethyl]phenolate-κ2O,O′}tris(thiocyanato-κNeuropium(III

    Directory of Open Access Journals (Sweden)

    Guo-Liang Zhao

    2009-12-01

    Full Text Available The metal center in the structure of the title compound, [Eu(NCS3(C15H15NO23], is coordinated by three Schiff base 2-methoxy-6-[(4-methylphenyliminiomethyl]phenolate (L ligands and three independent thiocyanate ions. In the crystal structure, the acidic H atom is located on the Schiff base N atom and hydrogen bonded to the phenolate O atom. The coordination environment of the EuIII ion is nine-coordinate by three chelating methoxyphenolate pairs of O atoms and three N-atom terminals of the thiocyanate ions. The compound is isostructural with the CeIII analogue [Liu et al. (2009. Acta Cryst. E65, m650].

  12. Refinement of macromolecular structures against neutron data with SHELXL2013.

    Science.gov (United States)

    Gruene, Tim; Hahn, Hinrich W; Luebben, Anna V; Meilleur, Flora; Sheldrick, George M

    2014-02-01

    Some of the improvements in SHELX2013 make SHELXL convenient to use for refinement of macromolecular structures against neutron data without the support of X-ray data. The new NEUT instruction adjusts the behaviour of the SFAC instruction as well as the default bond lengths of the AFIX instructions. This work presents a protocol on how to use SHELXL for refinement of protein structures against neutron data. It includes restraints extending the Engh & Huber [Acta Cryst. (1991), A47, 392-400] restraints to H atoms and discusses several of the features of SHELXL that make the program particularly useful for the investigation of H atoms with neutron diffraction. SHELXL2013 is already adequate for the refinement of small molecules against neutron data, but there is still room for improvement, like the introduction of chain IDs for the refinement of macromolecular structures.

  13. Redetermination of AgPO(3).

    Science.gov (United States)

    Terebilenko, Katherina V; Zatovsky, Igor V; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

    2011-02-09

    Single crystals of silver(I) polyphosphate(V), AgPO(3), were prepared via a phospho-ric acid melt method using a solution of Ag(3)PO(4) in H(3)PO(4). In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779-784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO(5)] polyhedra, giving rise to multidirectional ribbons, and from two types of PO(4) tetra-hedra linked into meandering chains (PO(3))(n) spreading parallel to the b axis with a repeat unit of four tetra-hedra. The calculated bond-valence sum value of one of the two Ag(I) ions indicates a significant strain of the structure.

  14. Redetermination of AgPO3

    Science.gov (United States)

    Terebilenko, Katherina V.; Zatovsky, Igor V.; Ogorodnyk, Ivan V.; Baumer, Vyacheslav N.; Slobodyanik, Nikolay S.

    2011-01-01

    Single crystals of silver(I) polyphosphate(V), AgPO3, were prepared via a phospho­ric acid melt method using a solution of Ag3PO4 in H3PO4. In comparison with the previous study based on single-crystal Weissenberg photographs [Jost (1961 ▶). Acta Cryst. 14, 779–784], the results were mainly confirmed, but with much higher precision and with all displacement parameters refined anisotropically. The structure is built up from two types of distorted edge- and corner-sharing [AgO5] polyhedra, giving rise to multidirectional ribbons, and from two types of PO4 tetra­hedra linked into meandering chains (PO3)n spreading parallel to the b axis with a repeat unit of four tetra­hedra. The calculated bond-valence sum value of one of the two AgI ions indicates a significant strain of the structure. PMID:21522230

  15. Triclinic modification of diaqua-bis-(5-carb-oxy-1H-imidazole-4-carboxyl-ato-κ(2)N(3),O(4))iron(II).

    Science.gov (United States)

    Ohshima, Eriko; Yoshida, Kazuki; Sugiyama, Kazumasa; Uekusa, Hidehiro

    2012-08-01

    The title compound, [Fe(C(5)H(3)N(2)O(4))(2)(H(2)O)(2)], is a triclinic modification of a monoclinic form recently reported by Du et al. [Acta Cryst. (2011) ▶, E67, m997]. The Fe(II) ion lies at an inversion center and is coordinated by two N and two O atoms from two 5-carb-oxy-1H-imidazole-4-carboxyl-ate ligands in trans positions, together with two water mol-ecules, completing a slightly distorted octahedral coordination. Inter-molecular N-H⋯O hydrogen bonding between the N-H group of the imidazole ring and the deprotonated carboxyl-ate group builds a chain of 5-carb-oxy-1H-imidazole-4-carboxyl-ate anions along the [101] direction. The water molecules form intermolecular hydrogen bonds to O-C and O=C sites of the carboxylate group in adjacent layers.

  16. Redetermined crystal structure of N-(β-carb-oxy-eth-yl)-α-isoleucine.

    Science.gov (United States)

    Chandrarekha, M; Srinivasan, N; Krishnakumar, R V

    2015-09-01

    Redetermination of the crystal structure of N-(β-carb-oxy-eth-yl)-α-isoleucine, C9H18N2O3, reported earlier by Nehls et al. [Acta Cryst. (2013), E69, o172-o173], was undertaken in which the ionization state assigned to the mol-ecule as unionized has been modified as zwitterionic in the present work. Single-crystal X-ray intensity data obtained from freshly grown crystals and freely refining the amino H atoms provide enhanced refinement and structural parameters, particularly the hydrogen-bonding scheme. N-H⋯O hydrogen bonds dominate the inter-molecular inter-actions along with a C-H⋯O hydrogen bond. The inter-molecular inter-action pattern is a three-dimensional network. The structure was refined as a two-component perfect inversion twin.

  17. A third polymorph of 1,4-bis(1H-benzimidazol-2-ylbenzene

    Directory of Open Access Journals (Sweden)

    Wei-Wei Fu

    2014-06-01

    Full Text Available The title compound, C20H14N4, is a new polymorph of the previously reported structures, which were orthorhombic, space group Pbca [Bei et al. (2000. Acta Cryst. C56, 718–719] and monoclinic, space group P21/c [Dudd et al. (2003. Green Chem. 5, 187–192]. The asymmetric unit consists of two independent molecules in which the dihedral angels between the central benzene ring and the outer benzimidazole ring systems are 16.81 (10 and 14.23 (10° in one molecule and 26.09 (10 and 37.29 (10° in the other. In the crystal, molecules are linked by N—H...N and C—H...N hydrogen bonds into a tape running along the c-axis direction.

  18. Statistical mechanics and the physics of fluids

    CERN Document Server

    Tosi, Mario

    This volume collects the lecture notes of a course on statistical mechanics, held at Scuola Normale Superiore di Pisa for third-to-fifth year students in physics and chemistry. Three main themes are covered in the book. The first part gives a compact presentation of the foundations of statistical mechanics and their connections with thermodynamics. Applications to ideal gases of material particles and of excitation quanta are followed by a brief introduction to a real classical gas and to a weakly coupled classical plasma, and by a broad overview on the three states of matter.The second part is devoted to fluctuations around equilibrium and their correlations. Coverage of liquid structure and critical phenomena is followed by a discussion of irreversible processes as exemplified by diffusive motions and by the dynamics of density and heat fluctuations. Finally, the third part is an introduction to some advanced themes: supercooling and the glassy state, non-Newtonian fluids including polymers and liquid cryst...

  19. Computational and instrumental methods in EPR

    CERN Document Server

    Bender, Christopher J

    2006-01-01

    Computational and Instrumental Methods in EPR Prof. Bender, Fordham University Prof. Lawrence J. Berliner, University of Denver Electron magnetic resonance has been greatly facilitated by the introduction of advances in instrumentation and better computational tools, such as the increasingly widespread use of the density matrix formalism. This volume is devoted to both instrumentation and computation aspects of EPR, while addressing applications such as spin relaxation time measurements, the measurement of hyperfine interaction parameters, and the recovery of Mn(II) spin Hamiltonian parameters via spectral simulation. Key features: Microwave Amplitude Modulation Technique to Measure Spin-Lattice (T1) and Spin-Spin (T2) Relaxation Times Improvement in the Measurement of Spin-Lattice Relaxation Time in Electron Paramagnetic Resonance Quantitative Measurement of Magnetic Hyperfine Parameters and the Physical Organic Chemistry of Supramolecular Systems New Methods of Simulation of Mn(II) EPR Spectra: Single Cryst...

  20. Na4.25Mo15S19: a novel ternary reduced molybdenum sulfide containing Mo6 and Mo9 clusters

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    D. Salloum

    2014-06-01

    Full Text Available The structure of tetrasodium pentadecamolybdenum nonadecasulfide, Na4.25Mo15S19, is isotypic with Na3.9Mo15Se19 [Salloum et al. (2013. Acta Cryst. E69, i67–i68]. It is characterized by Mo6Si8Sa6 and Mo9Si11Sa6 (where i represents inner and a apical atoms cluster units that are present in a 1:1 ratio. The cluster units are centered at Wyckoff positions 2b and 2c, and have point-group symmetry -3 and -6, respectively. The clusters are interconnected through additional Mo—S bonds. The Na+ cations occupy interunit voids formed by six or seven S atoms. One Mo, one S and one Na site [occupancy 0.751 (12] are situated on mirror planes, and two other S atoms and one Na site (full occupancy are situated on threefold rotation axes.

  1. Reinvestigation of the crystal structure of lautite, CuAsS

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    Paola Bonazzi

    2008-03-01

    Full Text Available The crystal structure of the mineral lautite (copper arsenic sulfide, CuAsS, previously described as either centrosymmetric [Pnma; Marumo & Nowacki (1964. Schweiz. Miner. Petro. Mitt. 44, 439–454] or noncentrosymmetric [Pna21; Craig & Stephenson (1965. Acta Cryst. 19, 543–547], was reinvestigated by means of single-crystal X-ray diffraction. The centrosymmetric structural model reported previously was confirmed, although with improved precision for the atomic coordinates and interatomic distances. Lautite shows a sphalerite-derivative structure with a linking of Cu[AsS3], As[CuAs2S] and S[Cu3As] tetrahedra. All atoms lie on special positions (Wyckoff position 4c, site symmetry m.

  2. Tl2Mo9Se11

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    Patrick Gougeon

    2010-08-01

    Full Text Available The structure of Tl2Mo9Se11, dithallium nonamolybdenum undecaselenide, is isotypic with Tl2Mo9S11 [Potel et al. (1980. Acta Cryst. B36, 1319–1322]. The structural set-up is characterized by a mixture of Mo6Sei8Sea6 and Mo12Sei14Sea6 cluster units in a 1:1 ratio. Both components are interconnected through interunit Mo—Se bonds. The cluster units are centered at Wyckoff positions 3a and 3b (point-group symmetry overline{3}.. The two TlI atoms are situated in the voids of the three-dimensional arrangement. Two of the five independent Se atoms and the Tl atoms lie on sites with 3. symmetry (Wyckoff site 6c.

  3. X-ray structure of Salmonella typhimurium uridine phosphorylase complexed with 5-fluorouracil and molecular modelling of the complex of 5-fluorouracil with uridine phosphorylase from Vibrio cholerae.

    Science.gov (United States)

    Lashkov, Alexander A; Sotnichenko, Sergey E; Prokofiev, Igor I; Gabdulkhakov, Azat G; Agapov, Igor I; Shtil, Alexander A; Betzel, Christian; Mironov, Alexander S; Mikhailov, Al'bert M

    2012-08-01

    Uridine phosphorylase (UPh), which is a key enzyme in the reutilization pathway of pyrimidine nucleoside metabolism, is a validated target for the treatment of infectious diseases and cancer. A detailed analysis of the interactions of UPh with the therapeutic ligand 5-fluorouracil (5-FUra) is important for the rational design of pharmacological inhibitors of these enzymes in prokaryotes and eukaryotes. Expanding on the preliminary analysis of the spatial organization of the active centre of UPh from the pathogenic bacterium Salmonella typhimurium (StUPh) in complex with 5-FUra [Lashkov et al. (2009), Acta Cryst. F65, 601-603], the X-ray structure of the StUPh-5-FUra complex was analysed at atomic resolution and an in silico model of the complex formed by the drug with UPh from Vibrio cholerae (VchUPh) was generated. These results should be considered in the design of selective inhibitors of UPhs from various species.

  4. Crystal structures of two ytterbium(III complexes comprising alkynylamidinate ligands

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    Sida Wang

    2016-09-01

    Full Text Available Two ytterbium(III complexes comprising alkynylamidinate ligands, namely bis(η5-cyclopentadienyl(3-cyclopropyl-N,N′-diisopropylpropynamidinato-κ2N,N′ytterbium(III, [Yb(C5H52(C12H19N2] or Cp2Yb[(iPr2N2C—C[triple-bond]C—c-C3H5] (1 and tris(3-phenyl-N,N′-dicyclohexylpropynamidinato-κ2N,N′ytterbium(III, [Yb(C21H27N23] or Yb[(CyN2C—C[triple-bond]C—Ph]3 (Cy = cyclohexyl (2 have been synthesized and structurally characterized. Both complexes are monomers; for complex 2, the contribution to the scattering from highly disordered toluene solvent molecules in these voids was removed with the SQUEEZE routine [Spek (2015. Acta Cryst. C71, 9–18] in PLATON. The stated crystal data for Mr, μ etc. do not take these into account.

  5. Crystal structure of bis­[tetra­kis­(tri­phenyl­phosphane-κP)silver(I)] (nitrilo­tri­acetato-κ4 N,O,O′,O′′)(tri­phenyl­phosphane-κP)argentate(I) with an unknown amount of methanol as solvate

    Science.gov (United States)

    Noll, Julian; Korb, Marcus; Lang, Heinrich

    2016-01-01

    The structure of the title compound, [Ag(C18H15P)4]2[Ag(C6H6NO6)(C18H15P)], exhibits trigonal (P-3) symmetry, with a C 3 axis through all three complex ions, resulting in an asymmetric unit that contains one third of the atoms present in the formula unit. The formula unit thus contains two of the cations, one anion and disordered mol­ecules of methanol as the packing solvent. Attempts to refine the solvent model were unsuccessful, indicating uninter­pretable disorder. Thus, the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9–18] was applied, accounting for 670 electrons per unit cell, representing approximately 18 mol­ecules of methanol in the formula unit. The stated crystal data for M r, μ etc do not take these into account. PMID:27006796

  6. The effect of intermolecular forces on diffusion in polymers

    CERN Document Server

    Chatten, R

    2002-01-01

    is proposed that since correlation function integral equation theories capture polymer-penetrant coupling effects the overall diffusion equation requires the simultaneous solution of a correlation function based polymer diffusion equation with only a random motion equation for the penetrant. It is demonstrated that a correlation function based theory is able to incorporate the mechanistic essence of both molecular models and free-volume theories whilst providing the possibility of interpretation of phenomenology at a more detailed level. The permeation of small molecules through polymer materials has been investigated both experimentally and theoretically. Experimentally the permeation of species from a Br sub 2 containing electrolyte through HDPE, LLDPE and PVDF has been examined using novel permeation cells. The effect of polymer and penetrant properties and environmental variables are discussed in conjunction with analyses of observed structural and dynamic features. Penetrant-induced changes such as cryst...

  7. Affinity and its derivatives in the glass transition process

    Science.gov (United States)

    Garden, J.-L.; Guillou, H.; Richard, J.; Wondraczek, L.

    2012-07-01

    The thermodynamic treatment of the glass transition remains an issue of intense debate. When associated with the formalism of non-equilibrium thermodynamics, the lattice-hole theory of liquids can provide new insight in this direction, as has been shown by Schmelzer and Gutzow [J. Chem. Phys. 125, 184511 (2006)], 10.1063/1.2374894, by Möller et al. [J. Chem. Phys. 125, 094505 (2006)], 10.1063/1.2346673, and more recently by Tropin et al. [J. Non-Cryst. Solids 357, 1291 (2011), 10.1016/j.jnoncrysol.2010.11.111; Tropin et al., J. Non-Cryst. Solids 357, 1303 (2011)], 10.1016/j.jnoncrysol.2010.12.005. Here, we employ a similar approach. We include pressure as an additional variable, in order to account for the freezing-in of structural degrees of freedom upon pressure increase. Second, we demonstrate that important terms concerning first order derivatives of the affinity-driving-force with respect to temperature and pressure have been previously neglected. We show that these are of crucial importance in the approach. Macroscopic non-equilibrium thermodynamics is used to enlighten these contributions in the derivation of Cp,κT, and αp. The coefficients are calculated as a function of pressure and temperature following different theoretical protocols, revealing classical aspects of vitrification and structural recovery processes. Finally, we demonstrate that a simple minimalist model such as the lattice-hole theory of liquids, when being associated with rigorous use of macroscopic non-equilibrium thermodynamics, is able to account for the primary features of the glass transition phenomenology. Notwithstanding its simplicity and its limits, this approach can be used as a very pedagogical tool to provide a physical understanding on the underlying thermodynamics which governs the glass transition process.

  8. A second polymorph of (2E-1-(4-fluorophenyl-3-(3,4,5-trimethoxyphenylprop-2-en-1-one

    Directory of Open Access Journals (Sweden)

    Jerry P. Jasinski

    2009-08-01

    Full Text Available The crystal structure of the title compound, C18H17FO4, reported here is a polymorph of the structure first reported by Patil et al. [Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. A (2007, 461, 123–130]. It is a chalcone analog and consists of substituted phenyl rings bonded at the opposite ends of a propenone group, the biologically active region. The dihedral angle between the mean planes of the aromatic rings within the 4-fluorophenyl and trimethoxyphenyl groups is 28.7 (1° compared to 20.8 (6° in the published structure. The angles between the mean plane of the prop-2-ene-1-one group and the mean plane of aromatic rings within the 4-fluorophenyl and trimethoxyphenyl groups are 30.3 (4 and 7.4 (7°, respectively, in contast to 10.7 (3 and 12.36° for the polymorph. While the two 3-methoxy groups are in the plane of the trimethoxy-substituted ring, the 4-methoxy group is in a synclinical [−sc = −78.1 (2°] or anticlinical [+ac = 104.0 (4°] position, compared to a +sc [53.0 (4°] or −ac [−132.4 (7°] position. While no classical hydrogen bonds are present, weak intermolecular C—H...π-ring interactions are observed which contribute to the stability of the crystal packing. The two polymorphs crystallize in the same space group, P21/c, but have different cell parameters for the a, b and c axes and the β angle. A comparison of the molecular geometries of both polymorphs to a geometry optimized density functional theory (DFT calculation at the B3-LYP/6–311+G(d,p level for each structure provides additional support to these observations.

  9. An approximation of the Cioslowski-Mixon bond order indexes using the AlteQ approach

    Science.gov (United States)

    Salmina, Elena; Grishina, Maria A.; Potemkin, Vladimir A.

    2013-09-01

    Fast and reliable prediction of bond orders in organic systems based upon experimentally measured quantities can be performed using electron density features at bond critical points (J Am Chem Soc 105:5061-5068, 1983; J Phys Org Chem 16:133-141, 2003; Acta Cryst B 61:418-428, 2005; Acta Cryst B 63:142-150, 2007). These features are outcomes of low-temperature high-resolution X-ray diffraction experiments. However, a time-consuming procedure of gaining these quantities makes the prediction limited. In the present work we have employed an empirical approach AlteQ (J Comput Aided Mol Des 22:489-505, 2008) for evaluation of electron density properties. This approach uses a simple exponential function derived from comparison of electron density, gained from high-resolution X-ray crystallography, and distance to atomic nucleus what allows calculating density distribution in time-saving manner and gives results which are very close to experimental ones. As input data AlteQ accepts atomic coordinates of isolated molecules or molecular ensembles (for instance, protein-protein complexes or complexes of small molecules with proteins, etc.). Using AlteQ characteristics we have developed regression models predicting Cioslowski-Mixon bond order (CMBO) indexes (J Am Chem Soc 113(42):4142-4145, 1991). The models are characterized by high correlation coefficients lying in the range from 0.844 to 0.988 dependently on the type of covalent bond, thereby providing a bonding quantification that is in reasonable agreement with that obtained by orbital theory. Comparative analysis of CMBOs approximated using topological properties of AlteQ and experimental electron densities has shown that the models can be used for fast determination of bond orders directly from X-ray crystallography data and confirmed that AlteQ characteristics can replace experimental ones with satisfactory extent of accuracy.

  10. Poly[μ2-chlorido-nonamethyl-μ3-nitrato-tritin(IV]. Corrigendum

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    Madeleine Helliwell

    2008-07-01

    Full Text Available An error in the original formulation of the title compound in the paper by Sadiq-ur-Rehman, Sherzaman, Ali, Shahzadi & Helliwell [Acta Cryst. (2007, E63, m2329] is corrected.The title compound in the paper by Sadiq-ur-Rehman, Sherzaman, Ali, Shahzadi & Helliwell [Acta Cryst. (2007, E63, m2329] was an unexpected product which seemed to have nitrate coordinated to three Sn atoms. However, it was noticed that the charges do not balance and that it is most likely that the nitrate is in fact a carbonate. Regrettably, there is no material to carry out microanalysis, but a plausible mechanism has been suggested to explain the unexpected formation of the product. Trimethyltin chloride will react with methanol in the presence of a base (4-hydroxypiperidine to give trimethyltin methoxide, which will rapidly hydrolyze in air to give the hydroxide. Both the methoxide and the hydroxide will react with atmospheric CO2 to give the carbonate (Bloodworth et al., 1967; Blunden et al., 1984; Sato, 1967. Me3SnCl + MeOH + base → Me3SnOMe + base·HCl Me3SnOMe + H2O → Me3SnOH + MeOH Me3SnOH + CO2 → Me3SnOCO2HMe3SnOCO2H + Me3SnOMe → Me3SnOCO2SnMe3 + MeOH. The carbonate then forms a coordination copolymer with trimethyltin chloride. The name of the title compound is corrected to poly[μ3-carbonato-μ3-chlorido-nonamethyltritin(IV], [Sn3(CH39(CO3Cl] (Mr = 586.84.

  11. Influence of the fluorescent brightener Periblanc BA on the degree of whiteness of the knitted cotton fabric

    Directory of Open Access Journals (Sweden)

    Miljković Milena N.

    2011-01-01

    Full Text Available In this study the influence of the different fluorescent brightener Periblanc BA concentrations on the degree of knitted cotton fabric whiteness was investigated. Two consecutive experimental runs were performed. The first was the bleaching of the knitted cotton fabric with hydrogen peroxide using the methods of two and single bath exhaustion while the second was the optical bleaching with fluorescent brightener Periblanc BA using the exhaustion method. CIE Whiteness Index and Tint value were measured on the Color-Eye 3000 spectrophotometer at the standard illuminant D65 (Ice-Texicon, d/8, D65/10° while K/S values were determined using the Kubelka Munk equation. The results show that cotton fabric bleached with fluorescent brightener Periblanc BA after bleaching with hydrogen peroxide using two bath exhaustion method has higher degree of whiteness (118.8 with a reddish tint in comparison to the one bleached with hydrogen peroxide using single bath method (106.1.

  12. Use of colour parameters for roasted coffee assessment

    Directory of Open Access Journals (Sweden)

    Natalina Cavaco Bicho

    2012-09-01

    Full Text Available Fast and non-destructive indicators were evaluated as tools to measure the technological quality of Arabica and Robusta coffee. Accordingly, considering the roasting intensity in highly valuable commercial samples, volume, mass, apparent density, moisture, total ash, ash insoluble in hydrochloric acid, and ether extract were characterized. The chromatic parameters L*, C*, Hº were measured using illuminants D65 and C. It was found that in roasted coffee beans, the parameters L*, C*, Hº, and coordinate b* had an antagonist interaction due to an increase in the roasting intensity, whereas after milling, only L* and Hº decreased progressively. Considering that the parameters L* and Hº followed similar patterns using both illuminants, D65 and C, it can be concluded that they are appropriate to evaluate coffee colour changes during roasting, enabling a relationship with coffee quality.

  13. Metameric effect between natural teeth and the shade tabs of a shade guide.

    Science.gov (United States)

    Corcodel, Nicoleta; Helling, Stephan; Rammelsberg, Peter; Hassel, Alexander J

    2010-06-01

    The objective of this study was to evaluate metameric effects, that is, the dependence of the colours of teeth and shade tabs on the illuminant used. The colours of 49 teeth of 37 participants and of the corresponding shade tabs of the 3D-Master (VITA Zahnfabrik; colour match DeltaE(ab)unity (indicating a greater colour difference relative to D65) by 57.1% for A and by 49.3% for TL84. Hue-angle ratios of teeth and tabs using the test illuminants were different from those obtained using the standard illuminant D65. If teeth and shade tab matching is conducted using daylight illumination, the colour difference may not be the same under other lighting conditions, leading to perceptible, or even unacceptable, colour differences under these conditions.

  14. Combat History Analysis Study Effort (CHASE) Data Enhancement Study (CDES). Volume 3. Task 2 and Task 3

    Science.gov (United States)

    1986-01-31

    Talavera , #128 Bussaco, #129 JA: D: 65,900 51,910 X X _ 65,900 51,910 0 0 4,500 1,300 61,400 50,610 Fuentes de Onoro, #130 |A: p...WINA" IRCHA’ ACHÜ i CHITLHIÜN I RESO I Talavera , #128 * i r ! 6 I .1 -1^ I -1 ACH Bussaco, #129 Fuentes de Onoro, #130* ACH

  15. Surface-Finish Measurement with Interference Microscopes,

    Science.gov (United States)

    1977-02-01

    5) Paducah Gaseous Diffusion Plant Bewley, H. D. 65 Redstone Arsenal Hutcheson, G. J. Union Carbide Corporation • New York Winters, Charles...Singer, S. Sollid, J. E. Oak Ridge Gaseous Diffusion Plant Stief, S. S. Wilcox.W. J.,Jr Oak Ridge National Laboratory Weir.J. R.,Jr OakRidge...February 1977 MIC QUALITY INSPECTED < UNION CARBIDE OAK RIDGE Y-12 PLANT OAK RIDGE. prepared for the U.S. ENERGY RESEARCH AND

  16. Illuminating light-dependent color shifts in core and veneer layers of dental all-ceramics.

    Science.gov (United States)

    Lee, Yong-Keun; Cha, Hyun-Suk; Yu, Bin

    2014-09-01

    The color of an object is perceived differently depending on the ambient light conditions. Since dental all-ceramic restorations are fabricated by building up several layers to reproduce the tooth shade, the optical properties of each layer should be optimized for successful shade reproduction. This study aimed to determine the separate contributions of the color shifts in each of the core and veneer layers of all-ceramics by switching the illuminating lights on the color shifts of layered ceramics. Specimens of seven kinds of core ceramics and the corresponding veneer ceramics for each core were fabricated with a layered thickness of 1.5 mm. A sintering ceramic was used as a reference core material. The Commission Internationale de l’Eclairage (CIE) color coordinates of core, veneer, and layered specimens were measured with a spectroradiometer under the CIE illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp) simulating lights. Color shifts of the layered specimens were primarily determined by the CIE a shifts (D65 to A switch) or by the CIE b shifts (D65 to F9 switch) of the veneer layer. The color coordinates shifts in the constituent layers differentially influenced those of the layered specimens by the kind of switched lights. Therefore, the optical properties of the constituent layers of all-ceramics should be controlled to reflect these findings.

  17. Effects of Light Source on the Color and Translucency of IPS e.max Press Core Ceramic%光源对IPS e.max(R)全瓷修复体颜色和半透明性的影响

    Institute of Scientific and Technical Information of China (English)

    李玲; 赵雯; 薛亮; 高婧; 孙翔; 邓再喜

    2013-01-01

    Objective:To evaluate the effect of the D65,A and F2 illuminant on the color and translucency of IPS e.max Press core ceramic.Methods:Specimens of IPS e.max Press MO1 core ceramic with different thicknesses were made.IPS e.max Ceram A2 was sintered on the core ceramic.The final thickness was controlled to 1.50 mm.The color parameters were measured with CM-700d Spectrophotometer.The translucency parameter and color difference (△E) between adjacent groups were calculated.Statistical analysis was done.Results:On the white background,based on all the specimens,the following results were obtained:L* values for A illuminant>F2 illuminant >D65 illuminant; a* values for A illuminant>D65 illuminant>F2 illuminant; b* values for F2 illuminant>A illuminant>D65 illuminant.With the increase of the ratio of core and dentine ceramic thickness,L* values for different illuminants increased,a* values,b* values and △E decreased.△E between different illuminants were as follows:A and D65 illuminant,4.15-4.89; F2 and D65 illuminant,2.87-3.55; F2 and A illuminant,4.63-5.53.Conclusion:Illuminant had a significant effect on the color and translucency of IPS e.max all-ceramic restoration.%目的:探讨D65 、A、F2光源下IPS e.max全瓷修复体的颜色和半透明性的影响.方法:制作不同厚度的IPS e.max Press MO1核瓷瓷片,在核瓷表面上堆塑IPS e.max Ceram A2牙本质瓷,使瓷试件最终厚度控制在1.50 mm.用CM-700d分光测色计分别测量各组试件不同光源下的颜色参数L*a*b*值,计算TP值和不同光源下的色差(△E),并对各组数据进行统计学分析.结果:在白背景下,各组试件的L*值在A光源下最大,其次是F2光源和D65光源,三者之间差异有统计学意义(P<0.01).a*值也是在A光源下最大,D65光源次之,最小是在F2光源下,三者之间有统计学差异(P<0.01).b*值变化为:F2光源>A光源>D65光源,三者之间差异有统计学意义(P<0.01).随着核瓷和牙本质瓷厚

  18. Illuminating light-dependent color shifts in core and veneer layers of dental all-ceramics

    Science.gov (United States)

    Lee, Yong-Keun; Cha, Hyun-Suk; Yu, Bin

    2014-09-01

    The color of an object is perceived differently depending on the ambient light conditions. Since dental all-ceramic restorations are fabricated by building up several layers to reproduce the tooth shade, the optical properties of each layer should be optimized for successful shade reproduction. This study aimed to determine the separate contributions of the color shifts in each of the core and veneer layers of all-ceramics by switching the illuminating lights on the color shifts of layered ceramics. Specimens of seven kinds of core ceramics and the corresponding veneer ceramics for each core were fabricated with a layered thickness of 1.5 mm. A sintering ceramic was used as a reference core material. The Commission Internationale de l'Eclairage (CIE) color coordinates of core, veneer, and layered specimens were measured with a spectroradiometer under the CIE illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp) simulating lights. Color shifts of the layered specimens were primarily determined by the CIE a* shifts (D65 to A switch) or by the CIE b* shifts (D65 to F9 switch) of the veneer layer. The color coordinates shifts in the constituent layers differentially influenced those of the layered specimens by the kind of switched lights. Therefore, the optical properties of the constituent layers of all-ceramics should be controlled to reflect these findings.

  19. Influence of the amount of UV component in daylight simulator on the color of dental composite resins.

    Science.gov (United States)

    Lu, Huan; Lee, Yong-Keun; Villalta, Patricia; Powers, John M; Garcia-Godoy, Franklin

    2006-11-01

    Color of fluorescent substances is influenced by the amount of ultraviolet (UV) component in the illumination. Color of fluorescent dental composite resins may change by the amount of UV component in the ambient light, but there have been few studies on this subject. The purpose of this study was to determine the differences in color and color parameters such as lightness, chroma, and hue of composite resins created by varying the amount of UV component of a pulsed-xenon source that is conditioned to approximate the Commission Internationale de l'Eclairage (CIE) standard illuminant D65. A spectrophotometer, in which the UV component of a daylight simulator could be adjusted, was developed. Eight light-polymerized dental composite resins, A3 shade, were studied. Five disk-shaped specimens, 10 x 3 mm, were prepared for each material. Color of specimens was measured on a reflection spectrophotometer over a white background relative to 3 illuminations, which had the same spectral power distribution of the CIE standard illuminant D65 in visible range, but different UV component. D65 indicated the illumination in which the UV component of the pulsed-xenon source was adjusted to the CIE standard illuminant D65 using a UV adjustment tile. UV-EXC indicated the illumination in which the UV component of the source was excluded with a UV filter. UV-INC indicated the illumination in which the UV component was included. Differences in color parameters by the illumination were analyzed with repeated-measures 1-way analysis of variance (ANOVA) by the brand of composite resins. Differences in color (DeltaE*(ab)) and color parameters such as lightness (DeltaL*), chroma (DeltaC*(ab)), and hue angle (Deltah) were analyzed with 3-way ANOVA, with the independent variables of brand of composite resin, combination of illuminations, and type of color parameters (alpha = .05). Color differences (DeltaE*(ab)) by the amount of UV component in the illuminations ranged between 0.3 and 1.4 for D

  20. X-Ray Data on Extraterrestrial CA Dialuminate (CaAl4O7)

    Science.gov (United States)

    Weber, D.; Ross, C. R., II; Bischoff, A.

    1993-07-01

    volume, are slightly higher in Ca-dialuminate from Acfer 182 than from synthetic CaAl4O7. This may be due to the incorporation of traces of refractory elements (REE) with large ionic radii, which were analyzed within inclusion 022/9 [10]. With the determination of the cell constants of natural Ca-dialuminate combined with data on synthetic CaAl4O7, sufficient X-ray data should be available required to nominate this mineral. References: [1] Christophe Michel-Levy M. et al. (1982) EPSL, 61, 13-22. [2] Kimura M. et al. (1993) GCA, in press. [3] Weber D. and Bischoff A. (1992) Meteoritics, 27, 304-305. [4] Weber D. and Bischoff A. (1993) GCA, submitted. [5] Boyko E. R. and Wisnyi L. G. (1958) Acta Cryst., 11, 444-445. [6] Goodwin D. W. and Lindop A. J. (1970) Acta Cryst., B26, 1230-1235. [7] Baldock P. J. et al. (1970) J. Appl. Cryst., 3, 188-191. [8] Geiger C. A. et al. (1988) GCA, 52, 1729-1736. [9] Gross S. (1977) Geol. Surv. Israel Bull. 70, 1-80. [10] Bischoff A. et al. (1992) Meteoritics, 27, 204. Table 1, which appears in the hard copy, shows unit-cell constants of Ca- dialuminate (monocline; space group C2/c) and X-ray powder diffraction data (CrK-alpha (Ni-beta), 45 kV, 30 mA) on extraterrestrial CaAl4O7 in comparison to JCPDS data [7]. Numbers in parentheses are uncertainties in last significant figures.

  1. Bulk Crystal Growth, and High-Resolution X-ray Diffraction Results of LiZnAs Semiconductor Material

    Science.gov (United States)

    Montag, Benjamin W.; Reichenberger, Michael A.; Sunder, Madhana; Ugorowski, Philip B.; Nelson, Kyle A.; Henson, Luke C.; McGregor, Douglas S.

    2017-08-01

    LiZnAs is being explored as a candidate for solid-state neutron detectors. The compact form, solid-state device would have greater efficiency than present day gas-filled 3He and 10BF3 detectors. Devices fabricated from LiZnAs having either natural Li (nominally 7.5% 6Li) or enriched 6Li (usually 95% 6Li) as constituent atoms may provide a material for compact high efficiency neutron detectors. The 6Li( n, t)4He reaction yields a total Q-value of 4.78 MeV, an energy larger than that of the 10B reaction, which can easily be identified above background radiations. LiZnAs material was synthesized by preparing equimolar portions of Li, Zn, and As sealed under vacuum (10-6 Torr) in quartz ampoules lined with boron nitride and subsequently reacted in a compounding furnace (Montag et al. in J Cryst Growth 412:103, 2015). The raw synthesized LiZnAs was purified by a static vacuum sublimation in quartz (Montag et al. in J Cryst Growth 438:99, 2016). Bulk crystalline LiZnAs ingots were grown from the purified material with a high-temperature Bridgman-style growth process described here. One of the largest LiZnAs ingots harvested was 9.6 mm in diameter and 4.2 mm in length. Samples were harvested from the ingot and were characterized for crystallinity using a Bruker AXS Inc. D8 AXS Inc. D2 CRYSO, energy dispersive x-ray diffractometer, and a Bruker AXS Inc. D8 DISCOVER, high-resolution x-ray diffractometer equipped with molybdenum radiation, Gobel mirror, four bounce germanium monochromator and a scintillation detector. The primary beam divergence was determined to be 0.004°, using a single crystal Si standard. The x-ray based characterization revealed that the samples nucleated in the (110) direction and a high-resolution open detector rocking curve recorded on the (220) LiZnAs yielded a full width at half maximum (FWHM) of 0.235°. Sectional pole figures using off-axis reflections of the (211) LiZnAs confirmed in-plane ordering, and also indicated the presence of multiple

  2. Effect of phase transformations on microstructures in deep mantle materials

    Science.gov (United States)

    Merkel, Sébastien; Langrand, Christopher; Rosa, Angelika; Hilairet, Nadège

    2017-04-01

    árik, Vaughan, Merkel, Reliability of Multigrain Indexing for Orthorhombic Polycrystals above 1 Mbar: Application to MgSiO3-Post-Perovskite, J Appl Cryst 50, in press (2017) Rosa, Hilairet, Ghosh, Garbarino, Jacobs, Perrillat, Vaughan, Merkel, In situ monitoring of phase transformation microstructures at Earth's mantle pressure and temperature using multi-grain XRD, J Appl Cryst 48, 1346-1354 (2015) Rosa, Hilairet, Ghosh, Perrillat, Garbarino, Merkel, Evolution of grain sizes and orientations during phase transitions in hydrous Mg2SiO4, J Geophys Res 121, 7161-7176 (2016)

  3. The Exploitation of Versatile Building Blocks for the Self-Assembly of Novel Molecular Magnets

    Science.gov (United States)

    Pilkington, M.; Gross, M.; Franz, P.; Biner, M.; Decurtins, S.; Stoeckli-Evans, H.; Neels, A.

    2001-07-01

    Using molecular building blocks to self-assemble lattices supporting long-range magnetic order is currently an active area of solid-state chemistry. Consequently, it is the realm of supramolecular chemistry that synthetic chemists are turning to in order to develop techniques for the synthesis of structurally well-defined supramolecular materials. In recent years we have investigated the versatility and usefulness of two classes of molecular building blocks, namely, tris-oxalato transition-metal (M. Pilkington and S. Decurtins, in "Magnetoscience-From Molecules to Materials," Wiley-VCH, 2000), and octacyanometalate complexes (Pilkington and Decurtins, Chimia 54, 593 (2001)), for applications in the field of molecule-based magnets. Anionic, tris-chelated oxalato building blocks are able to build up two-dimensional honeycomb-layered structural motifs as well as three-dimensional decagon frameworks. The discrimination between the crystallization of the two- or three-dimensional structures relies on the choice of the templating counterions (Decurtins, Chimia 52, 539 (1998); Decurtins et al. Mol. Cryst. Liq. Cryst. 273, 167 (1995); New J. Chem. 117 (1998)). These structural types display a range of ferro, ferri, and antiferromagnetic properties (Pilkington and Decurtins, in "Magnetoscience-From Molecules to Materials"). Octacyanometalate building blocks self-assemble to afford two new classes of cyano-bridged compounds namely, molecular clusters and extended three dimensional networks (J. Larionova et al., Angew. Chem. Int. Ed. 39, 1605 (2000); Pilkington et al., in preparation). The molecular cluster with a MnII9MoV6 core has the highest ground state spin value, S=51/2, reported to-date (Larionova et al., Angew. Chem. Int. Ed. 39, 1605 (2000)). In the high-temperature regime, the magnetic properties are characterized by ferromagnetic intracluster coupling. In the magnetic range below 44 K, the magnetic cluster signature is lost as possibly a bulk behavior starts to

  4. Optimal configurations of filter cavity in future gravitational-wave detectors

    CERN Document Server

    Khalili, Farit Ya

    2010-01-01

    Sensitivity of future laser interferometric gravitational-wave detectors can be improved using squeezed light with frequency-dependent squeeze angle and/or amplitude, which can be created using additional so-called filter cavities. Here we compare performances of several variants of this scheme, proposed during last years, assuming the case of a single relatively short (tens of meters) filter cavity suitable for implementation already during the life cycle of the second generation detectors, like Advanced LIGO. Using numerical optimization, we show that the phase filtering scheme proposed by Kimble et al [Phys.Rev.D 65, 022002 (2001)] looks as the best candidate for this scenario.

  5. A study about illumination and colors vision

    Energy Technology Data Exchange (ETDEWEB)

    Toadere, Florin, E-mail: florin.toadere@itim-cj.r [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)

    2009-08-01

    In this paper we propose a software algorithm which can simulate the human eyes colors view. We present a spectral image processing algorithm, in which we use the color checker spectral image, the human eyes cones spectral sensitivity and the spectral power distribution for light sources. We use three spectrums of real lamps, made by EG and G PerkinElmer: sunlight 5500K, xenon flash and xenon CW, and three CIE light standard sources: D65, CIE A and F7. In order to validate the functionality of the algorithm we simulate the color checker picture hues difference, under different illuminations generate with the light spectrums presented in this paper.

  6. Optical influence of different standard illuminants on green nephrite's color From Manasi

    Science.gov (United States)

    Du, Hong-mei; Guo, Ying

    2010-11-01

    To evaluate the optical influence of illuminant on green color with low chroma (C*~1~12) of nephrite from Manasi, three different standard illuminant-daylight D65, incandescent light A and fluorescent light F2 (CWF) were applied during the experiment. Two-way ANOVA was used to analyze the illuminants tested considering the coordinates of lightness L* and chromaticity a*, b*. The results indicate significant differences for L*, a* and b* (pnephrite's color grading while light source A can be used during trading.

  7. The Relationship Between the Color Characteristics of the RGB Colorimetric System and the Physicochemical Properties of Petroleums and high Boiling Hydrocarbon Distillates

    Science.gov (United States)

    Dolomatov, M. Yu.; Yarmuhametova, G. U.

    2016-09-01

    An interrelation was established between physicochemical properties of oils and high boiling hydrocarbon distillates and their solutions' color characteristics defi ned in the RGB colorimetric system using a standard radiation source CIE D65. It was shown that by using color characteristics of solutions of the specifi ed objects, it was possible to determine their relative density, molecular mass, activation energy of viscous fl ow, and the coking value. Research results were confi rmed by statistical data processing using the methods of multivariate regression and correlation analysis.

  8. Effect of various vitamin D metabolites on serum calcium and inorganic phosphate in the freshwater snake Natrix piscator.

    Science.gov (United States)

    Srivastav, A K; Srivastav, S K; Singh, S; Norman, A W

    1995-10-01

    Vitamin D3 (650 pmol and 6.50 nmol/100 g body wt), 25-hydroxyvitamin D (650 pmol and 6.50 nmol/100 g body wt), and 1,25-dihydroxyvitamin D (65 pmol and 650 pmol/100 g body wt) were administered daily to the freshwater snake Natrix piscator for 15 days. Both serum calcium and inorganic phosphate levels were increased significantly in all of the treated groups. This is the first report of hypercalcemia and hyperphosphatemia in reptiles induced by 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D.

  9. Chloro(L-glutamato-kappa 2N,O)(1,10-phenanthroline-kappa 2,N')copper(II) monohydrate.

    Science.gov (United States)

    Lu, Li-Ping; Zhu, Miao-Li; Yang, Pin

    2004-01-01

    The crystal structure of the title compound, [CuCl(C(5)H(8)NO(4))(C(12)H(8)N(2))].H(2)O or [CuCl(L-Glu)(phen)].H(2)O (where phen is 1,10-phenanthroline and L-Glu is L-glutamate), shows that the ternary complex consists of two neutral molecules, in which the Cu(II) ions each have a distorted square-pyramidal coordination geometry comprised of one bidentate phenanthroline ligand, one O,N-bidentate L-glutamate anion and an apical Cl(-) anion. The angles between the planes of the Cu-phenanthroline and the Cu-aminocarboxylate chelate rings are 6.1 (5) and 11.8 (5) degrees in the two molecules. The Cu-Cl bond lengths are 2.608 (3) and 2.590 (3) A in the two molecules, slightly longer than the value of 2.546 A observed for the Cu-Cl bond in the analogous chloro(L-glycinato)(1,10-phenanthroline)copper complex [Solans, Ruiz-Ramírez, Martinez, Gasque & Briansó (1983). Acta Cryst. C44, 628-631]. Additionally, the Cu ion is weakly coordinated at a sixth position by an alpha-carboxyl O atom from a neighbouring complex. A number of intra- and intermolecular hydrogen bonds stabilize the crystal structure.

  10. Protein Circular Dichroism Data Bank (PCDDB): data bank and website design.

    Science.gov (United States)

    Whitmore, Lee; Janes, Robert W; Wallace, B A

    2006-06-01

    The Protein Circular Dichroism Data Bank (PCDDB) is a new deposition data bank for validated circular dichroism spectra of biomacromolecules. Its aim is to be a resource for the structural biology and bioinformatics communities, providing open access and archiving facilities for circular dichroism and synchrotron radiation circular dichroism spectra. It is named in parallel with the Protein Data Bank (PDB), a long-existing valuable reference data bank for protein crystal and NMR structures. In this article, we discuss the design of the data bank structure and the deposition website located at http://pcddb.cryst.bbk.ac.uk. Our aim is to produce a flexible and comprehensive archive, which enables user-friendly spectral deposition and searching. In the case of a protein whose crystal structure and sequence are known, the PCDDB entry will be linked to the appropriate PDB and sequence data bank files, respectively. It is anticipated that the PCDDB will provide a readily accessible biophysical catalogue of information on folded proteins that may be of value in structural genomics programs, for quality control and archiving in industrial and academic labs, as a resource for programs developing spectroscopic structural analysis methods, and in bioinformatics studies.

  11. Structure and dynamics of iron doped and undoped silicate glasses

    Science.gov (United States)

    Santos, Cristiane N.; Meneses, Domingos D. S.; Echegut, Patrick; Lecomte, Emmanuel

    2010-03-01

    The optical properties of common silicate glass compositions are well known at room temperature. However, their radiative properties and structural evolution of these glasses with temperature are still largely unexplored. In this work we have measured the emissivity of a set of iron doped and undoped silicate and borosilicate glasses over an unprecedented temperature (up to 1700 K) and spectral range (40 -- 20000 cm-1). This was achieved by means of a home-made apparatus composed of a CO2 laser as the heat source, a black-body reference and two spectrometers. The optical functions were assessed using a dielectric function model [1], and the structure and dynamics of the glassy network, as well the absorption of iron species in different redox states were evidenced. We believe that these new data will help to understand the heat transfer in molten silicates. [4pt] [1] D. D. S. Meneses, G. Gruener, M. Malki, and P. Echegut, J. Non-Cryst. Solids 351, 124 (2005)

  12. Structure of thallium and lead calculated from Shaw local pseudopotential and molecular dynamics

    Directory of Open Access Journals (Sweden)

    Gasser J. G.

    2011-05-01

    Full Text Available Recently, we (Es Sbihi Phil. Mag 2010 have successfully calculated, by molecular dynamics, the static structure factor of liquid bismuth at different temperatures. Our results were in very good agreement with the Waseda experimental data. Our assumption was to consider the true density of states which presents a gap as measured by Indlekofer (J. Non-Cryst. Solids 1989 and calculated by Hafner-Jank (Phys. Rev. B 1990 for liquid bismuth. The number of electrons at the Fermi energy has been calculated with three conduction electrons for bismuth (number of p electrons. With this assumption, the structures were determined with an effective ion-ion potential constructed from the Shaw local Optimised Model Potential (OMP and the Ichimaru-Utsumi dielectric function. In the present paper, we generalize our assumptions to liquid thallium and lead which also present such a gap. Their calculated structures are also very close to the experimental ones. This confirms that the number of conduction electrons on the Fermi sphere is consistent with the number of p electrons as has been even shown for our electronic transport properties of liquid lead (A. Ben Abdellah, Phys. Rev. B 2003.

  13. 2,4-Bis(4-ethoxyphenyl-7-methyl-3-azabicyclo[3.3.1]nonan-9-one

    Directory of Open Access Journals (Sweden)

    V. Ramkumar

    2012-03-01

    Full Text Available The molecule of the title compound, C25H31NO3, exists in a twin-chair conformation with an equatorial orientation of the 4-ethoxyphenyl groups, as observed for its ortho isomer [Parthiban, Ramkumar, Park & Jeong (2011b, Acta Cryst. E67, o1475–o1476]. The methyl and 4-ethoxyphenyl groups are also equatorially oriented on the bicycle, as in the ortho analogue. In particular, although the cyclohexanone ring deviates from an ideal chair, the piperidone ring is closer to an ideal chair, whereas in the ortho isomer both rings are significantly puckered and deviate from ideal chairs. The 4-ethoxyphenyl groups on both sides of the secondary amine group are oriented at an angle of 26.11 (3° with respect to each other, but the 2-ethoxyphenyl groups in the ortho isomer are oriented by less than half this [12.41 (4°]. In contrast to the absence of any significant interactions in the crystal packing of the ortho isomer, the title compound features N—H...O interactions, linking the molecules along the b axis.

  14. Bis[2-(hy-droxy-imino-meth-yl)phenolato]nickel(II): a second monoclinic polymorph.

    Science.gov (United States)

    Rusanova, Julia A; Buvaylo, Elena A; Rusanov, Eduard B

    2011-01-15

    The title compound, [Ni(C(7)H(6)NO(2))(2)], (I), is a second monoclinic polymorph of the compound, (II), reported by Srivastava et al. [Acta Cryst. (1967), 22, 922] and Mereiter [Private communication (2002) CCDC refcode NISALO01]. The bond lengths and angles are similar in both structures. The mol-ecule in both structures lies on a crystallographic inversion center and both have an inter-nal hydrogen bond. The title compound crystallizes in the space group P2(1)/c (Z = 2), whereas compound (II) is in the space group P2(1)/n (Z = 2) with a similar cell volume but different cell parameters. In both polymorphs, mol-ecules are arranged in the layers but in contrast to the previously published compound (II) where the dihedral angle between the layers is 86.3°, in the title polymorph the same dihedral angle is 29.4°. The structure of (I) is stabilized by strong intra-molecular O-H⋯O hydrogen bonding between the O-H group and the phenolate O atom.

  15. Bis[2-(hydroxyiminomethylphenolato]nickel(II: a second monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Julia A. Rusanova

    2011-02-01

    Full Text Available The title compound, [Ni(C7H6NO22], (I, is a second monoclinic polymorph of the compound, (II, reported by Srivastava et al. [Acta Cryst. (1967, 22, 922] and Mereiter [Private communication (2002 CCDC refcode NISALO01]. The bond lengths and angles are similar in both structures. The molecule in both structures lies on a crystallographic inversion center and both have an internal hydrogen bond. The title compound crystallizes in the space group P21/c (Z = 2, whereas compound (II is in the space group P21/n (Z = 2 with a similar cell volume but different cell parameters. In both polymorphs, molecules are arranged in the layers but in contrast to the previously published compound (II where the dihedral angle between the layers is 86.3°, in the title polymorph the same dihedral angle is 29.4°. The structure of (I is stabilized by strong intramolecular O—H...O hydrogen bonding between the O—H group and the phenolate O atom.

  16. Does mathematical crystallography still have a role in the XXI century?

    Science.gov (United States)

    Nespolo, Massimo

    2008-01-01

    Mathematical crystallography is the branch of crystallography dealing specifically with the fundamental properties of symmetry and periodicity of crystals, topological properties of crystal structures, twins, modular and modulated structures, polytypes and OD structures, as well as the symmetry aspects of phase transitions and physical properties of crystals. Mathematical crystallography has had its most evident success with the development of the theory of space groups at the end of the XIX century; since then, it has greatly enlarged its applications, but crystallographers are not always familiar with the developments that followed, partly because the applications sometimes require some additional background that the structural crystallographer does not always possess (as is the case, for example, in graph theory). The knowledge offered by mathematical crystallography is at present only partly mirrored in International Tables for Crystallography and is sometimes still enshrined in more specialist texts and publications. To cover this communication gap is one of the tasks of the IUCr Commission on Mathematical and Theoretical Crystallography (MaThCryst).

  17. Nomenclature of magnetic, incommensurate, composition-changed morphotropic, polytype, transient-structural and quasicrystalline phases undergoing phase transitions. II. Report of an IUCr Working Group on Phase Transition Nomenclature.

    Science.gov (United States)

    Tolédano, J C; Berry, R S; Brown, P J; Glazer, A M; Metselaar, R; Pandey, D; Perez-Mato, J M; Roth, R S; Abrahams, S C

    2001-09-01

    A general nomenclature applicable to the phases that form in any sequence of transitions in the solid state has been recommended by an IUCr Working Group [Acta Cryst. (1998). A54, 1028-1033]. The six-field notation of the first Report, hereafter I, was applied to the case of structural phase transitions, i.e. to transformations resulting from temperature and/or pressure changes between two crystalline (strictly periodic) phases involving modifications to the atomic arrangement. Extensive examples that illustrate the recommendations were provided. This second Report considers, within the framework of a similar six-field notation, the more complex nomenclature of transitions involving magnetic phases, incommensurate phases and transitions that occur as a function of composition change. Extension of the nomenclature to the case of phases with less clearly established relevance to standard schemes of transition in equilibrium systems, namely polytype phases, radiation-induced and other transient phases, quasicrystalline phases and their transitions is recommended more tentatively. A uniform notation for the translational periodicity, propagation vector or wavevector for magnetic and/or incommensurate substances is specified. The notation adopted for incommensurate phases, relying partly on the existence of an average structure, is also consistent with that for commensurate phases in a sequence. The sixth field of the nomenclature is used to emphasize the special features of polytypes and transient phases. As in I, illustrative examples are provided for each category of phase sequence.

  18. Crystal families and systems in higher dimensions, and geometrical symbols of their point groups. I. Crystal families in five-dimensional space with two-, three-, four- and sixfold symmetries.

    Science.gov (United States)

    Veysseyre, R; Weigel, D; Phan, Th

    2008-11-01

    The aim of this paper and of the following one [Weigel, Phan & Veysseyre (2008). Acta Cryst. A64, 687-697] is to complete the list of the Weigel-Phan-Veysseyre (WPV) symbols of the point groups of space E5 that was started in previous papers and in two reports of an IUCr Subcommittee on the Nomenclature of n-Dimensional Crystallography. In this paper, some crystal families of space E5 are studied. The cells of these are right hyperprisms with as a basis either two squares, or two hexagons, or a square and a hexagon. If the basis is made up of two squares, the two families are the (monoclinic di squares)-al family (No. XVI) and the (di squares)-al family (No. XIX). If the basis is made up of two hexagons, the two families are the (monoclinic di hexagons)-al family (No. XVII) and the (di hexagons)-al family (No. XXI). If the basis is made up of one square and one hexagon, the family is the (square hexagon)-al family (No. XX). In order to link space E5 to spaces E2, E3 and E4, some results published in previous papers are recalled. In fact, most of the symbols of the point groups of space E5 can be deduced from the symbols of the four, six and 23 crystal families of spaces E2, E3 and E4, respectively.

  19. V1.42In1.83Mo15Se19

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    Michel Potel

    2010-10-01

    Full Text Available The structure of the title compound, vanadium indium pentadecamolybdenum nonadecaselenide, V1.42In1.83Mo15Se19, is isotypic with In2.9Mo15Se19 [Grüttner et al. (1979. Acta Cryst. B35, 285–292]. It is characterized by two cluster units Mo6Sei8Sea6 and Mo9Sei11Sea6 (where i represents inner and a apical atoms that are present in a 1:1 ratio. The cluster units are centered at Wyckoff positions 2b and 2c and have point-group symmetry overline{3} and overline{6}, respectively. The clusters are interconnected through additional Mo—Se bonds. In the title compound, the V3+ cations replace the trivalent indium atoms present in In2.9Mo15Se19, and a deficiency is observed on the monovalent indium site. One Mo, one Se and the V atom are situated on mirror planes, and two other Se atoms and the In atom are situated on threefold rotation axes.

  20. Rappertk: a versatile engine for discrete restraint-based conformational sampling of macromolecules

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    Karmali Anjum M

    2007-03-01

    Full Text Available Abstract Background Macromolecular structures are modeled by conformational optimization within experimental and knowledge-based restraints. Discrete restraint-based sampling generates high-quality structures within these restraints and facilitates further refinement in a continuous all-atom energy landscape. This approach has been used successfully for protein loop modeling, comparative modeling and electron density fitting in X-ray crystallography. Results Here we present a software toolkit (Rappertk which generalizes discrete restraint-based sampling for use in structural biology. Modular design and multi-layered architecture enables Rappertk to sample conformations of any macromolecule at many levels of detail and within a variety of experimental restraints. Performance against a Cα-tracing benchmark shows that the efficiency has not suffered despite the overhead required by this flexibility. We demonstrate the toolkit's capabilities by building high-quality β-sheets and by introducing restraint-driven sampling. RNA sampling is demonstrated by rebuilding a protein-RNA interface. Ability to construct arbitrary ligands is used in sampling protein-ligand interfaces within electron density. Finally, secondary structure and shape information derived from EM are combined to generate multiple conformations of a protein consistent with the observed density. Conclusion Through its modular design and ease of use, Rappertk enables exploration of a wide variety of interesting avenues in structural biology. This toolkit, with illustrative examples, is freely available to academic users from http://www-cryst.bioc.cam.ac.uk/~swanand/mysite/rtk/index.html.

  1. A second orthorhombic polymorph of (Z-3-(9-anthryl-1-(2-thienylprop-2-en-1-oneThis paper is dedicated to His Majesty King Bhumibol Adulyadej of Thailand (King Rama IX for his sustainable development of the country.

    Directory of Open Access Journals (Sweden)

    Suchada Chantrapromma

    2010-02-01

    Full Text Available The title heteroaryl chalcone, C21H14OS, is a second orthorhombic polymorph which crystallizes in the space group P212121. The structure was previously reported [Fun et al. (2009. Acta Cryst. E65, o2168-o2169] in the space group Pna21. The bond distances and angles are similar in both structures. In contrast, the overall crystal packing is different from that in the first orthorhombic Pna21 polymorph in which molecules were stacked into columns along the b axis and the thiophene units of two adjacent columns were stacked in a head to tail fashion. In the present polymorph, molecules are found to dimerize through a weak S...S interaction [3.6513 (7 Å] and these dimers are arranged into sheets parallel to the bc plane. There are no classical hydrogen bonds in the packing which features short C...O [3.2832 (2–3.6251 (9 Å], C...S [3.4879 (17–3.6251 (19 Å] and S...O [2.9948 (16 Å] contacts, together with C—H...π interactions. Similar contacts were found in the other polymorph.

  2. Crystal structure of lead(II tartrate: a redetermination

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    Matthias Weil

    2015-01-01

    Full Text Available Single crystals of poly[μ4-tartrato-κ6O1,O3:O1′:O2,O4:O4′-lead], [Pb(C4H4O6]n, were grown in a gel medium. In comparison with the previous structure determination of this compound from laboratory powder X-ray diffraction data [De Ridder et al. (2002. Acta Cryst. C58, m596–m598], the redetermination on the basis of single-crystal data reveals the absolute structure, all atoms with anisotropic displacement parameters and a much higher accuracy in terms of bond lengths and angles. It could be shown that a different space group or incorporation of water as reported for similarly gel-grown lead tartrate crystals is incorrect. In the structure, each Pb2+ cation is bonded to eight O atoms of five tartrate anions, while each tartrate anion links four Pb2+ cations. The resulting three-dimensional framework is stabilized by O—H...O hydrogen bonds between the OH groups of one tartrate anion and the carboxylate O atoms of adjacent anions.

  3. Probability density functions of the average and difference intensities of Friedel opposites.

    Science.gov (United States)

    Shmueli, U; Flack, H D

    2010-11-01

    Trigonometric series for the average (A) and difference (D) intensities of Friedel opposites were carefully rederived and were normalized to minimize their dependence on sin(theta)/lambda. Probability density functions (hereafter p.d.f.s) of these series were then derived by the Fourier method [Shmueli, Weiss, Kiefer & Wilson (1984). Acta Cryst. A40, 651-660] and their expressions, which admit any chemical composition of the unit-cell contents, were obtained for the space group P1. Histograms of A and D were then calculated for an assumed random-structure model and for 3135 Friedel pairs of a published solved crystal structure, and were compared with the p.d.f.s after the latter were scaled up to the histograms. Good agreement was obtained for the random-structure model and a qualitative one for the published solved structure. The results indicate that the residual discrepancy is mainly due to the presumed statistical independence of the p.d.f.'s characteristic function on the contributions of the interatomic vectors.

  4. Pharmacokinetics of Peramivir in an Adolescent Patient Receiving Continuous Venovenous Hemodiafiltration.

    Science.gov (United States)

    Dillon, Ryan C; Witcher, Robert; Cies, Jeffrey J; Moore, Wayne S; Chopra, Arun

    2017-01-01

    Critically ill patients requiring renal replacement therapy commonly experience pharmacokinetic alterations. This case report describes the pharmacokinetics of peramivir (Rapivab, BioCryst Pharmaceuticals, Inc, Durham, NC), the first US Food and Drug Administration-approved intravenous neuraminidase inhibitor for the treatment of influenza, in an adolescent patient receiving continuous renal replacement therapy (CRRT). A 49.5-kg, 17-year-old Caucasian female presented with fever, cough, and persistent hypoxia. She quickly progressed to acute respiratory and renal failure in the setting of viral septic shock as a result of a severe influenza H1N1 infection. On hospital day 3, therapy was switched from oseltamivir (Tamiflu, Roche Laboratories Inc, Nutley, NJ) to peramivir owing to the concern for inadequate enteral absorption. On the third day of peramivir treatment, at a dose of 200 mg daily, peramivir serum concentrations revealed a smaller peak concentration, larger volumes of distribution, similar 24-hour area under the curve, and a shorter half-life as compared to adult patients with normal renal function. This illustrated the significant differences in pharmacokinetics when administered in the setting of CRRT. The patient had resolution of viral infection as evidenced by negative respiratory viral panel polymerase chain reaction at hospital day 14 and was eventually discharged at her baseline.

  5. Crystal structure of tri-aqua-(2,6-di-methyl-pyrazine-κN (4))bis-(thio-cyanato-κN)manganese(II) 2,5-di-methyl-pyrazine disolvate.

    Science.gov (United States)

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

    2015-12-01

    In the crystal structure of the title complex, [Mn(NCS)2(C6H8N2)(H2O)3]·2C6H8N2, the Mn(II) cation is coordinated by two terminally N-bonded thio-cyanate anions, three water mol-ecules and one 2,6-di-methyl-pyrazine ligand within a slightly distorted N3O3 octa-hedral geometry; the entire complex mol-ecule is generated by the application of a twofold rotation axis. The asymmetric unit also contains an uncoordinating 2,5-di-methyl-pyrazine ligand in a general position. Obviously, the coordination to the 2,6-di-methyl-pyrazine ligand is preferred because coordination to the 2,5-di-methyl-pyrazine is hindered due to the bulky methyl group proximate to the N atom. The discrete complexes are linked by water-O-H⋯N(2,6-di-methyl-pyzazine/2,5-di-methyl-pyza-zine) hydrogen bonding, forming a three-dimensional network. In the crystal, mol-ecules are arranged in a way that cavities are formed in which unspecified, disordered solvent molecules reside. These were modelled employing the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The composition of the unit cell does not take into account the presence of the unspecified solvent.

  6. Crystal structure of 4-methyl-N-{(E-methyl[(3aR,8aS-2-oxo-3,3a,8,8a-tetrahydro-2H-indeno[1,2-d][1,3]oxazol-3-yl]-λ4-sulfanylidene}benzenesulfonamide

    Directory of Open Access Journals (Sweden)

    Patrícia A. Pereira

    2015-12-01

    Full Text Available The formulation that the title compound, C18H18N2O4S2, adopts is a zwitterionic core with the charge separated to the sulfilimine S and N atoms and is supported by the two different S—N bond distances about the sulfinimine N atom [1.594 (2 and 1.631 (2 Å, respectively] that are typical for such bonds. The notably unusual bond is S—N(oxazolidinone [1.692 (2 Å] that is longer than a typical S—N bond [1.603 (18 Å, Mogul analysis; Macrae et al. (2008. J. Appl. Cryst. 41, 466–470]. The bond-angle sum about sulfilimine sulfur (308.35° reflects the trigonal–pyramidal geometry of this atom. Two of the angles are less than 100°. Despite the pyramidalization of this sulfur, there are no significant intermolecular interactions, beyond usual van der Waals contacts, in the crystal packing.

  7. Crystal structure of bis(azido-κNbis[2,5-bis(pyridin-2-yl-1,3,4-thiadiazole-κ2N2,N3]cobalt(II

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    Abdelhakim Laachir

    2015-05-01

    Full Text Available In the mononuclear title complex, [Co(N32(C12H8N4S2], the cobalt(II atom is located on an inversion centre and displays an axially weakly compressed octahedral coordination geometry. The equatorial positions are occupied by the N atoms of two 2,5-bis(pyridin-2-yl-1,3,4-thiadiazole ligands, whereas the axial positions are occupied by N atoms of the azide anions. The thiadiazole and pyridine rings linked to the metal are almost coplanar, with a maximum deviation from the mean plane of 0.0273 (16 Å. The cohesion of the crystal is ensured by weak C—H...N hydrogen bonds and by π–π interactions between pyridine rings [intercentroid distance = 3.6356 (11 Å], forming a layered arrangement parallel to (001. The structure of the title compound is isotypic with that of the analogous nickel(II complex [Laachir et al. (2013. Acta Cryst. E69, m351–m352].

  8. An ortho-rhom-bic polymorph of N (1),N (4)-diphenyl-3,6-bis-(phenyl-imino)-cyclo-hexa-1,4-diene-1,4-di-amine.

    Science.gov (United States)

    Ohno, Keiji; Fujihara, Takashi; Nagasawa, Akira

    2014-04-01

    A new ortho-rhom-bic polymorph of the title compound, C30H24N4, with a density of 1.315 Mg m(-3), has been obtained. The mol-ecule is centrosymmetric with the centroid of the cyclo-hexa-1,4-diene ring located on an inversion center. The two unique benzene rings are almost perpendicular to each other [dihedral angle = 86.70 (6)°] and are oriented at dihedral angles of 30.79 (5) and 68.07 (5)° with respect to the central cyclo-hexa-diene ring. In the crystal, π-π stacking is observed between the central cyclo-hexa-1,4-diene-1,4-di-amine unit and a phenyl ring of a neighboring mol-ecule [centroid-centroid distance = 3.7043 (7) Å]. The crystal structure of the triclinic polymorph [Ohno et al. (2014 ▶). Acta Cryst. E70, o303-o304] showed chains running along the b-axis direction through weak C-H⋯π inter-actions.

  9. Efficient Exciton Transfer from In0.35Ga0.65As Template into InAs Quantum Dots Grown on GaAs (311)B Substrates

    Institute of Scientific and Technical Information of China (English)

    WANG Fang-Zhen; CHEN Zhang-Hai; GONG Qian; R. N(o)tzel; BAI Li-Hui; SHEN Xue-Chu

    2006-01-01

    @@ Atomic force microscopy (AFM) and power-dependent micro-photoluminescence (μ-PL) spectroscopy are used to study the structure and exciton energy states in InAs quantum dots (QDs) grown on an In0.35 Ga0.65As template on GaAs (311)B. The In0.35Ga0.65As template, consisting of a two-dimensionally modulated layer of closely packed connected cells, has a remarkable effect on the optical properties of the InAs QDs. By comparing the emission spectra of the samples without and with InAs QDs and the work carried out by Gong et al. [J. Cryst.Growth 251 (2003) 150; Appl. Phys. Lett. 81 (2002) 3254] we conclude that the existence of the In0.35Ga0.65As template enhances the photo-absorption and therefore the exciton emission from the QDs due to efficient exciton transfer from the template into the QDs. Furthermore, the PL emission from the QDs clearly reveals four discrete energy levels, S, P, D, and F with increasing excitation power.

  10. Crystal structure of ethyl 3-amino-6-methyl-2-[(4-methylphenylcarbamoyl]-4-[(E-2-phenylethenyl]thieno[2,3-b]pyridine-5-carboxylate monohydrate

    Directory of Open Access Journals (Sweden)

    Joel T. Mague

    2016-03-01

    Full Text Available In the title molecule, C27H25N3O3S·H2O, the dihedral angle between the planes of the thienyl ring and the pendant p-tolyl group is 39.25 (6°, while that between the pyridine ring and the pendant phenyl ring is 44.37 (6°. In addition, there is a slight twist in the bicyclic core, with a dihedral angle of 2.39 (4° between the thienyl and pyridine rings. The conformation of the carbamoyl moiety is partially determined by an intramolecular N—H...O hydrogen bond. In the crystal, complementary N—H...O hydrogen bonds form dimers which are then associated into chains parallel to the c axis through O—H...N hydrogen bonds involving the water molecule of crystallization. Electron density associated with an additional solvent molecule of partial occupancy and disordered about a twofold axis was removed with the SQUEEZE procedure in PLATON [Spek (2015. Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s.

  11. Facilitating model reconstruction for single-particle scattering using small-angle X-ray scattering methods.

    Science.gov (United States)

    Ma, Shufen; Liu, Haiguang

    2016-04-01

    X-ray free-electron lasers generate intense femtosecond X-ray pulses, so that high-resolution structure determination becomes feasible from noncrystalline samples, such as single particles or single molecules. At the moment, the orientation of sample particles cannot be precisely controlled, and consequently the unknown orientation needs to be recovered using computational algorithms. This delays the model reconstruction until all the scattering patterns have been re-oriented, which often entails a long elapse of time and until the completion of the experiment. The scattering patterns from single particles or multiple particles can be summed to form a virtual powder diffraction pattern, and the low-resolution region, corresponding to the small-angle X-ray scattering (SAXS) regime, can be analysed using existing SAXS methods. This work presents a pipeline that converts single-particle data sets into SAXS data, from which real-time model reconstruction is achieved using the model retrieval approach implemented in the software package SASTBX [Liu, Hexemer & Zwart (2012). J. Appl. Cryst.45, 587-593]. To illustrate the applications, two case studies are presented with real experimental data sets collected at the Linac Coherent Light Source.

  12. On the correlation between hydrogen bonding and melting points in the inositols

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    Sándor L. Bekö

    2014-01-01

    Full Text Available Inositol, 1,2,3,4,5,6-hexahydroxycyclohexane, exists in nine stereoisomers with different crystal structures and melting points. In a previous paper on the relationship between the melting points of the inositols and the hydrogen-bonding patterns in their crystal structures [Simperler et al. (2006. CrystEngComm 8, 589], it was noted that although all inositol crystal structures known at that time contained 12 hydrogen bonds per molecule, their melting points span a large range of about 170 °C. Our preliminary investigations suggested that the highest melting point must be corrected for the effect of molecular symmetry, and that the three lowest melting points may need to be revised. This prompted a full investigation, with additional experiments on six of the nine inositols. Thirteen new phases were discovered; for all of these their crystal structures were examined. The crystal structures of eight ordered phases could be determined, of which seven were obtained from laboratory X-ray powder diffraction data. Five additional phases turned out to be rotator phases and only their unit cells could be determined. Two previously unknown melting points were measured, as well as most enthalpies of melting. Several previously reported melting points were shown to be solid-to-solid phase transitions or decomposition points. Our experiments have revealed a complex picture of phases, rotator phases and phase transitions, in which a simple correlation between melting points and hydrogen-bonding patterns is not feasible.

  13. Etude structurale et vibrationnelle d'un nouveau composé complexe de cobalt: [Co(imidazole4Cl]Cl

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    Amira Derbel

    2015-10-01

    Full Text Available In the title complex, chloridotetrakis(1H-imidazole-κN3cobalt(II chloride, [CoCl(C3H4N24]Cl, the CoII cation has a distorted square-pyramidal coordination environment. It is coordinated by four N atoms of four imidazole (Im groups in the basal plane, and by a Cl atom in the apical position. It is isostructural with [Cu(Im4Cl]Cl [Morzyk-Ociepa et al. (2012. J. Mol. Struct. 1028, 49–56] and [Cu(Im4Br]Br [Hossaini Sadr et al. (2004. Acta Cryst. E60, m1324–m1326]. In the crystal, the [CoCl(C3H4N24]+ cations and Cl− anions are linked via N—H...Cl hydrogen bonds, forming layers parallel to (010. These layers are linked via C—H...Cl hydrogen bonds and C—H...π and π–π [inter-centroid distance = 3.794 (2 Å] interactions, forming a three-dimensional framework. The IR spectrum shows vibrational bands typical for imidazol groups. The monoclinic unit cell of the title compound emulates an orthorhombic cell as its β angle is close to 90°. The crystal is twinned, with the refined ratio of twin components being 0.569 (1:0.431 (1.

  14. A log-likelihood-gain intensity target for crystallographic phasing that accounts for experimental error.

    Science.gov (United States)

    Read, Randy J; McCoy, Airlie J

    2016-03-01

    The crystallographic diffraction experiment measures Bragg intensities; crystallographic electron-density maps and other crystallographic calculations in phasing require structure-factor amplitudes. If data were measured with no errors, the structure-factor amplitudes would be trivially proportional to the square roots of the intensities. When the experimental errors are large, and especially when random errors yield negative net intensities, the conversion of intensities and their error estimates into amplitudes and associated error estimates becomes nontrivial. Although this problem has been addressed intermittently in the history of crystallographic phasing, current approaches to accounting for experimental errors in macromolecular crystallography have numerous significant defects. These have been addressed with the formulation of LLGI, a log-likelihood-gain function in terms of the Bragg intensities and their associated experimental error estimates. LLGI has the correct asymptotic behaviour for data with large experimental error, appropriately downweighting these reflections without introducing bias. LLGI abrogates the need for the conversion of intensity data to amplitudes, which is usually performed with the French and Wilson method [French & Wilson (1978), Acta Cryst. A35, 517-525], wherever likelihood target functions are required. It has general applicability for a wide variety of algorithms in macromolecular crystallography, including scaling, characterizing anisotropy and translational noncrystallographic symmetry, detecting outliers, experimental phasing, molecular replacement and refinement. Because it is impossible to reliably recover the original intensity data from amplitudes, it is suggested that crystallographers should always deposit the intensity data in the Protein Data Bank.

  15. Crystal structure of di-chlorido-(2,2':6',2''-terpyridine-κ(3) N,N',N'')zinc: a redeter-min-ation.

    Science.gov (United States)

    Kong, Cheng-Cheng; Zhou, Jia-Zheng; Yu, Jian-Hua; Li, Sheng-Li

    2014-11-01

    The crystal structure of the title compound, [ZnCl2(C15H11N3)], was redetermined based on modern CCD data. In comparison with the previous determination from photographic film data [Corbridge & Cox (1956 ▶). J. Chem. Soc. 159, 594-603; Einstein & Penfold (1966 ▶). Acta Cryst. 20, 924-926], all non-H atoms were refined with anisotropic displacement parameters, leading to a much higher precision in terms of bond lengths and angles [e.g. Zn-Cl = 2.2684 (8) and 2.2883 (11) compared to 2.25 (1) and 2.27 (1) Å]. In the title mol-ecule, the Zn(II) atom is five-coordinated in a distorted square-pyramidal mode by two Cl atoms and by the three N atoms from the 2,2':6',2''-terpyridine ligand. The latter is not planar and shows dihedral angles between the least-squares planes of the central pyridine ring and the terminal rings of 3.18 (8) and 6.36 (9)°. The mol-ecules in the crystal structure pack with π-π inter-actions [centroid-centroid distance = 3.655 (2) Å] between pyridine rings of neighbouring terpyridine moieties. These, together with inter-molecular C-H⋯Cl inter-actions, stablize the three-dimensional structure.

  16. Distinguishing tautomerism in the crystal structure of (Z)-N-(5-ethyl-2,3-dihydro-1,3,4-thiadiazol-2-ylidene)-4-methylbenzenesulfonamide using DFT-D calculations and (13)C solid-state NMR.

    Science.gov (United States)

    Li, Xiaozhou; Bond, Andrew D; Johansson, Kristoffer E; Van de Streek, Jacco

    2014-08-01

    The crystal structure of the title compound, C11H13N3O2S2, has been determined previously on the basis of refinement against laboratory powder X-ray diffraction (PXRD) data, supported by comparison of measured and calculated (13)C solid-state NMR spectra [Hangan et al. (2010). Acta Cryst. B66, 615-621]. The molecule is tautomeric, and was reported as an amine tautomer [systematic name: N-(5-ethyl-1,3,4-thiadiazol-2-yl)-p-toluenesulfonamide], rather than the correct imine tautomer. The protonation site on the molecule's 1,3,4-thiadiazole ring is indicated by the intermolecular contacts in the crystal structure: N-H...O hydrogen bonds are established at the correct site, while the alternative protonation site does not establish any notable intermolecular interactions. The two tautomers provide essentially identical Rietveld fits to laboratory PXRD data, and therefore they cannot be directly distinguished in this way. However, the correct tautomer can be distinguished from the incorrect one by previously reported quantitative criteria based on the extent of structural distortion on optimization of the crystal structure using dispersion-corrected density functional theory (DFT-D) calculations. Calculation of the (13)C SS-NMR spectrum based on the correct imine tautomer also provides considerably better agreement with the measured (13)C SS-NMR spectrum.

  17. Interfacial instabilities in directional solidification of dilute binary alloys: The Kuramoto-Sivashinsky equation

    Science.gov (United States)

    Novick-Cohen, A.

    1987-05-01

    Directional solidification processes in the presence of an impurity are studied in the limit in which the dimensionless parameter overlineW = {GD}/{VC}0( g + ⨍ c) is small. Here G is the imposed temperature gradient, D is the diffusion coefficient of the impurity, V is the imposed transport velocity, g is equal to minus the slope of the liquidus line, C0 is the impurity concentration at the liquid side of a planar interface, and ⨍ c is a coefficient reflecting deviations from local thermal equilibrium. The dynamics of interfacial kinetics becomes important in this limit and the phenomenological model of Coriell and Sekerka [J. Cryst. Growth 61 (1983) 499-508] is used to model these processes. In this limit, the Kuramoto-Sivashinsky equation is shown to be an asymptotically valid description of the interfacial dynamics. The Kuramoto-Sivashinsky equation is known to exhibit intermittancy superimposed on a relatively stable array of cusps or wrinkles [Michelson and Sivashinsky, Acta Astronautica 4 (1977) 1207-1221] and thus may give a reasonable limiting description of the solidification interface just before coherency is lost. These cusps may also be important in the initiation of dendritic growth by serving as defect points [Schaefer and Glicksman, Met. Trans. 1 (1970) 1973-1978].

  18. Structure of Physarum polycephalum cytochrome b{sub 5} reductase at 1.56 Å resolution

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sangwoo; Suga, Michihiro; Ogasahara, Kyoko [Institute for Protein Research, Osaka University, 3-2 Yamada-oka, Suita, Osaka (Japan); Ikegami, Terumi; Minami, Yoshiko; Yubisui, Toshitsugu [Department of Biochemistry, Okayama University of Science, 1-1 Ridai-cho, Okayama 700-0005 (Japan); Tsukihara, Tomitake, E-mail: tsuki@protein.osaka-u.ac.jp [Institute for Protein Research, Osaka University, 3-2 Yamada-oka, Suita, Osaka (Japan)

    2007-04-01

    The structure of P. polycephalum cytochrome b{sub 5} reductase, an enzyme which catalyzes the reduction of cytochrome b{sub 5} by NADH, was determined at a resolution of 1.56 Å. Physarum polycephalum cytochrome b{sub 5} reductase catalyzes the reduction of cytochrome b{sub 5} by NADH. The structure of P. polycephalum cytochrome b{sub 5} reductase was determined at a resolution of 1.56 Å. The molecular structure was compared with that of human cytochrome b{sub 5} reductase, which had previously been determined at 1.75 Å resolution [Bando et al. (2004 ▶), Acta Cryst. D60, 1929–1934]. The high-resolution structure revealed conformational differences between the two enzymes in the adenosine moiety of the FAD, the lid region and the linker region. The structural properties of both proteins were inspected in terms of hydrogen bonding, ion pairs, accessible surface area and cavity volume. The differences in these structural properties between the two proteins were consistent with estimates of their thermostabilities obtained from differential scanning calorimetry data.

  19. Acanthamoeba polyphaga mimivirus NDK: preliminary crystallographic analysis of the first viral nucleoside diphosphate kinase

    Energy Technology Data Exchange (ETDEWEB)

    Jeudy, Sandra [Information Génomique et Structurale, CNRS UPR 2589, 31 Chemin Joseph Aiguier, 13402 Marseille CEDEX 20 (France); Coutard, Bruno [Architecture et Fonction des Macromolecules Biologiques, CNRS UMR 6098, 31 Chemin Joseph Aiguier, 13402 Marseille CEDEX 20 (France); Lebrun, Régine [IBSM, 31 Chemin Joseph Aiguier, 13402 Marseille CEDEX 20 (France); Abergel, Chantal, E-mail: chantal.abergel@igs.cnrs-mrs.fr [Information Génomique et Structurale, CNRS UPR 2589, 31 Chemin Joseph Aiguier, 13402 Marseille CEDEX 20 (France)

    2005-06-01

    A. polyphaga mimivirus, the largest known double-stranded DNA virus, is the first virus to exhibit a nucleoside diphosphate kinase gene. The expression and crystallization of the viral NDK are reported. The complete sequence of the largest known double-stranded DNA virus, Acanthamoeba polyphaga mimivirus, has recently been determined [Raoult et al. (2004 ▶), Science, 306, 1344–1350] and revealed numerous genes not expected to be found in a virus. A comprehensive structural and functional study of these gene products was initiated [Abergel et al. (2005 ▶), Acta Cryst. F61, 212–215] both to better understand their role in the virus physiology and to obtain some clues to the origin of DNA viruses. Here, the preliminary crystallographic analysis of the viral nucleoside diphosphate kinase protein is reported. The crystal belongs to the cubic space group P2{sub 1}3, with unit-cell parameter 99.425 Å. The self-rotation function confirms that there are two monomers per asymmetric unit related by a twofold non-crystallographic axis and that the unit cell thus contains four biological entities.

  20. Raster-scanning serial protein crystallography using micro- and nano-focused synchrotron beams

    Energy Technology Data Exchange (ETDEWEB)

    Coquelle, Nicolas [Université Grenoble Alpes, IBS, 38044 Grenoble (France); CNRS, IBS, 38044 Grenoble (France); CEA, IBS, 38044 Grenoble (France); Brewster, Aaron S. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Kapp, Ulrike; Shilova, Anastasya; Weinhausen, Britta [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble (France); Burghammer, Manfred, E-mail: burgham@esrf.fr [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble (France); Ghent University, Ghent B-9000 (Belgium); Colletier, Jacques-Philippe, E-mail: burgham@esrf.fr [Université Grenoble Alpes, IBS, 38044 Grenoble (France); CNRS, IBS, 38044 Grenoble (France); CEA, IBS, 38044 Grenoble (France)

    2015-05-01

    A raster scanning serial protein crystallography approach is presented, that consumes as low ∼200–700 nl of sedimented crystals. New serial data pre-analysis software, NanoPeakCell, is introduced. High-resolution structural information was obtained from lysozyme microcrystals (20 µm in the largest dimension) using raster-scanning serial protein crystallography on micro- and nano-focused beamlines at the ESRF. Data were collected at room temperature (RT) from crystals sandwiched between two silicon nitride wafers, thereby preventing their drying, while limiting background scattering and sample consumption. In order to identify crystal hits, new multi-processing and GUI-driven Python-based pre-analysis software was developed, named NanoPeakCell, that was able to read data from a variety of crystallographic image formats. Further data processing was carried out using CrystFEL, and the resultant structures were refined to 1.7 Å resolution. The data demonstrate the feasibility of RT raster-scanning serial micro- and nano-protein crystallography at synchrotrons and validate it as an alternative approach for the collection of high-resolution structural data from micro-sized crystals. Advantages of the proposed approach are its thriftiness, its handling-free nature, the reduced amount of sample required, the adjustable hit rate, the high indexing rate and the minimization of background scattering.

  1. A non-solvated form of [(Z-O-methyl-N-(2-methylphenylthiocarbamato-κS](triphenylphosphane-κPgold(I: crystal structure and Hirshfeld surface analysis

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    Chien Ing Yeo

    2016-10-01

    Full Text Available The title compound, [Au(C9H10NOS(C18H15P], features a near linear P—Au—S arrangement defined by phosphane P and thiolate S atoms with the minor distortion from the ideal [P—Au—S is 177.61 (2°] being traced in part to the close intramolecular approach of an O atom [Au...O = 3.040 (2 Å]. The packing features supramolecular layers lying parallel to (011 sustained by a combination of C—H...π and π–π [inter-centroid distance = 3.8033 (17 Å] interactions. The molecular structure and packing are compared with those determined for a previously reported hemi-methanol solvate [Kuan et al. (2008. CrystEngComm, 10, 548–564]. Relatively minor differences are noted in the conformations of the rings in the Au-containing molecules. A Hirshfeld surface analysis confirms the similarity in the packing with the most notable differences relating to the formation of C—H...S contacts between the constituents of the solvate.

  2. A second monoclinic polymorph of 2-(diformylmethylidene-3,3-dimethyl-2,3-dihydro-1H-indole

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    Hamid Khaledi

    2009-10-01

    Full Text Available The crystal structure of the title compound, C13H13NO2, is a polymorph of the structure first reported by Helliwell et al. [Acta Cryst. (2006, E62, o737-o738]. It is also monoclinic (space group P21/c, but with completely different cell constants. The molecular conformations of these polymorphs differ by a 180° rotation of one formyl group. The present molecule is planar [maximum deviation 0.089 (2 Å] with the exception of the two methyl groups which lie on either side of the plane. There are strong intra- and intermolecular N—H...O hydrogen bonds. The latter link pairs of molecules across crystallographic centers of symmetry. Two aldehyde O atoms are brought close together [2.896 (4 Å in this arrangement but are not hydrogen bonded. In the earlier polymorph, one formyl group is rotated by 180° to yield intermolecular hydrogen bonding and an infinite polymeric chain. The other formyl group is involved in the same intramolecular hydrogen bonding as has been found here.

  3. Crystal structure of tetrakis[μ2-2-(dimethylaminoethanolato-κ3N,O:O]di-μ3-hydroxido-dithiocyanato-κ2N-dichromium(IIIdilead(II dithiocyanate acetonitrile monosolvate

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    Julia A. Rusanova

    2016-04-01

    Full Text Available The tetranuclear complex cation of the title compound, [Cr2Pb2(NCS2(OH2(C4H10NO4](SCN2·CH3CN, lies on an inversion centre. The main structural feature of the cation is a distorted seco-norcubane Pb2Cr2O6 cage with a central four-membered Cr2O2 ring. The CrIII ion is coordinated in a distorted octahedron, which involves two N atoms of one bidentate ligand and one thiocyanate anion, two μ2-O atoms of 2-(dimethylaminoethanolate ligands and two μ3-O atoms of hydroxide ions. The coordination geometry of the PbII ion is a distorted disphenoid, which involves one N atom, two μ2-O atoms and one μ3-O atom. In addition, weak Pb...S interactions involving the coordinating and non-coordinating thiocyanate anions are observed. In the crystal, the complex cations are linked through the thiocyanate anions via the Pb...S interactions and O—H...N hydrogen bonds into chains along the c axis. The chains are further linked together via S...S contacts. The contribution of the disordered solvent acetonitrile molecule was removed with the SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] procedure in PLATON. The solvent is included in the reported molecular formula, weight and density.

  4. Crystal structure of an unknown tetrahydrofuran solvate of tetrakis(μ3-cyanato-κ3N:N:Ntetrakis[(triphenylphosphane-κPsilver(I

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    Peter Frenzel

    2015-10-01

    Full Text Available In the title compound, [{[(C6H53P]Ag}4{NCO}4], a distorted Ag4N4-heterocubane core is set up by four AgI ions being coordinated by the N atoms of the cyanato anions in a μ3-bridging mode. In addition, a triphenylphosphine ligand is datively bonded to each of the AgI ions. Intramolecular Ag...Ag distances as short as 3.133 (9 Å suggest the presence of argentophilic (d10...d10 interactions. Five moderate-to-weak C—H...O hydrogen-bonding interactions are observed in the crystal structure, spanning a three-dimensional network. A region of electron density was treated with the SQUEEZE procedure in PLATON [Spek (2015. Acta Cryst. C71, 9–18] following unsuccessful attempts to model it as being part of disordered tetrahydrofuran solvent molecules. The given chemical formula and other crystal data do not take into account these solvent molecules.

  5. Molecular and crystal structure of gossypol tetramethyl ether with an unknown solvate

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    Muhabbat Honkeldieva

    2015-02-01

    Full Text Available The title compound, C34H38O8 (systematic name: 5,5′-diisopropyl-2,2′,3,3′-tetramethoxy-7,7′-dimethyl-2H,2′H-8,8′-bi[naphtho[1,8-bc]furan]-4,4′-diol, has been obtained from a gossypol solution in a mixture of dimethyl sulfate and methanol. The molecule is situated on a twofold rotation axis, so the asymmetric unit contains one half-molecule. In the molecule, the hydroxy groups are involved in intramolecular O—H...O hydrogen bonds, and the two naphthyl fragments are inclined each to other by 83.8 (1°. In the crystal, weak C—H...O and C—H...π interactions consolidate the packing, which exhibits channels with an approximate diameter of 6 Å extending along the c-axis direction. These channels are filled with highly disordered solvent molecules, so their estimated scattering contribution was subtracted from the observed diffraction data using the SQUEEZE option in PLATON [Spek, A. L. (2015. Acta Cryst. C71, 9–18].

  6. Crystal structure of 2-methylamino-4-(6-methyl-4-oxo-4H-chromen-3-yl-3-nitropyrano[3,2-c]chromen-5(4H-one with an unknown solvate

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    Rajamani Raja

    2015-09-01

    Full Text Available In the title compound, C23H16N2O7, the mean planes of the two chromene units (r.m.s. deviations = 0.031 and 0.064 Å are almost normal to one another with a dihedral angle of 85.59 (6°. The central six-membered pyran ring has a distorted envelope conformation, with the methine C atom at the flap. There is an intramolecular N—H...O hydrogen bond, which generates an S(6 ring motif. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds, forming inversion dimers with an R22(12 ring motif. The dimers are linked by pairs of C—H...O hydrogen bonds, enclosing R22(6 ring motifs, forming zigzag chains along [001]. The chains are linked by a second pair of C—H...O hydrogen bonds, forming slabs parallel to (110. Within the slabs there are C—H...π interactions present. A region of disordered electron density was treated with the SQUEEZE procedure in PLATON [Spek (2015. Acta Cryst. C71, 9–18] following unsuccessful attempts to model it as plausible solvent molecule(s. The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s.

  7. Crystal structure of 2-[(3S,4S-4-(anthracen-9-yl-1-(4-methoxyphenyl-2-oxoazetidin-3-yl]-2-aza-2H-phenalene-1,3-dione unknown solvate

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    Ísmail Çelik

    2015-03-01

    Full Text Available The central β-lactam ring of the title compound, C36H24N2O4, is almost planar (r.m.s. deviation = 0.003 Å and makes dihedral angles of 17.17 (19, 89.76 (17 and 78.44 (17° with the benzene ring, the anthracene ring (r.m.s. deviation = 0.003 Å and the 1H-benzo[de]isoquinoline-1,3(2H-dione moiety, which is nearly planar [maximum deviation = 0.098 (2 Å], respectively. The molecular structure is stabilized by an intramolecular C—H...N hydrogen bond. In the crystal, molecules are linked via C—H...π and π–π stacking interactions [centroid–centroid distances = 3.5270 (19 and 3.779 (2 Å], forming a three-dimensional structure. A region of disordered electron density, probably disordered solvent molecules, was treated with the SQUEEZE procedure in PLATON [Spek (2015. Acta Cryst. C71, 9–18], which indicated a solvent cavity of 322 Å3 containing approximately 91 electrons. Their formula mass and unit-cell characteristics were not taken into account during the refinement.

  8. Crystal structure of an unknown solvate of bis(tetra-n-butylammonium [N,N′-(4-trifluoromethyl-1,2-phenylenebis(oxamato-κ4O,N,N′,O′]nickelate(II

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    François Eya'ane Meva

    2015-06-01

    Full Text Available In the title compound, [N(C4H94]2[Ni(C11H3F3N2O6] or [N(n-Bu4]2[Ni(topbo] [n-Bu = n-butyl and topbo = 4-trifluoromethyl-1,2-phenylenebis(oxamate], the Ni2+ cation is coordinated by two deprotonated amido N atoms and two carboxylate O atoms, setting up a slightly distorted square-planar coordination environment. The [Ni(topbo]2− anion lies on a twofold rotation axis. Due to an incompatibility with the point-group symmetry of the complete molecule, orientational disorder of the CF3 group is observed. The tetrahedral ammonium cations and the anion are linked by weak intermolecular C—H...O and C—H...F hydrogen-bonding interactions into a three-dimensional network. A region of electron density was treated with the SQUEEZE procedure in PLATON [Spek (2015. Acta Cryst. C71, 9–18] following unsuccessful attempts to model it as plausible solvent molecule(s. The given chemical formula and other crystal data do not take into account the unknown solvent molecule.

  9. (RS-Efonidipine acetone hemisolvate

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    Yu-Heng Liu

    2016-09-01

    Full Text Available The asymmetric unit of the title compound, C34H38N3O7P·0.5C3H6O {systematic name: (RS-2-[phenyl(phenylmethylamino]ethyl 5-(5,5-dimethyl-2-oxo-1,3-dioxa-2λ5-phosphacyclohex-2-yl-2,6-dimethyl-4-(3-nitrophenyl-1,4-dihydropyridine-3-carboxylate acetone hemisolvate}, contains one R-efonidipine molecule, one S-efonidipine molecule and half of a solvate acetone molecule. In both efonidipine molecules, the six-membered rings of the dioxaphosphinanyl moieties display a chair conformation and the dihydropyridine rings display a flattened boat conformation. In the crystal, N—H...O, C—H...O hydrogen bonds and weak C—H...π interactions link the molecules into a three-dimensional supramolecular structure. A solvent-accessible void of 199 Å3 is found in the structure; the contribution of the heavily disordered solvate molecule was suppressed by use of the SQUEEZE routine in PLATON [Spek (2015. Acta Cryst. C71, 9–18].

  10. Crystal structure of triaqua(2,6-dimethylpyrazine-κN4bis(thiocyanato-κNmanganese(II 2,5-dimethylpyrazine disolvate

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    Stefan Suckert

    2015-12-01

    Full Text Available In the crystal structure of the title complex, [Mn(NCS2(C6H8N2(H2O3]·2C6H8N2, the MnII cation is coordinated by two terminally N-bonded thiocyanate anions, three water molecules and one 2,6-dimethylpyrazine ligand within a slightly distorted N3O3 octahedral geometry; the entire complex molecule is generated by the application of a twofold rotation axis. The asymmetric unit also contains an uncoordinating 2,5-dimethylpyrazine ligand in a general position. Obviously, the coordination to the 2,6-dimethylpyrazine ligand is preferred because coordination to the 2,5-dimethylpyrazine is hindered due to the bulky methyl group proximate to the N atom. The discrete complexes are linked by water-O—H...N(2,6-dimethylpyzazine/2,5-dimethylpyzazine hydrogen bonding, forming a three-dimensional network. In the crystal, molecules are arranged in a way that cavities are formed in which unspecified, disordered solvent molecules reside. These were modelled employing the SQUEEZE routine in PLATON [Spek (2015. Acta Cryst. C71, 9–18]. The composition of the unit cell does not take into account the presence of the unspecified solvent.

  11. (4′-Phenyl-2,2′:6′,2′′-terpyridine-κ3N,N′,N′′bis(thiocyanato-κNzinc(II unknown solvate

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    An-ran Wang

    2016-11-01

    Full Text Available The title compound, [Zn(NCS2(C21H15N3], crystallizes with three independent complex molecules in the asymmetric unit. In each complex molecule, the ZnII atom is coordinated by three N atoms of a 4′-phenyl-2,2′:6′,2′′-terpyridine ligand, and by the N atoms of two NCS− anions. The ZnII atoms are therefore five-coordinate, ZnN5, with distorted square-pyramidal geometries. In the crystal, the three independent molecules are linked by a series of offset π–π interactions [intercentroid distances vary between 3.680 (5 and 3.791 (5 Å], forming columns along the a-axis direction. The columns are linked via C—H...S interactions, forming a fence-like arrangement parallel to the ab plane. A small region of disordered electron density was corrected for using the SQUEEZE routine in PLATON [Spek (2015. Acta Cryst. C71, 9–18], but the formula mass and unit-cell characteristics were not taken into account during the refinement.

  12. Bromidocarbonyl{(1S,2S-N-[2-(dicyclohexylphosphanylethylidenyl]-N′-[2-(diphenylphosphanylethyl]-1,2-diphenylethane-1,2-diamine}iron(II tetraphenylborate

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    Samantha A. M. Smith

    2017-03-01

    Full Text Available In the title compound, trans-(S,S-[FeBr(CO(PPh2CH2CH2NHCHPhCHPhNCHCH2PCy2]BPh4, the FeII ion is in a distorted octahedral complex geometry with a cis-β ligand geometry in which two diastereomers co-crystallized in the asymmetric unit. These diastereomers differ by the orientation of the N—H moieties on the ligand; one is in the S conformation (A, and the other R (B. Diasteromer A has a P—Fe—P angle of 104.36 (6° and B has a P—Fe—P angle of 102.70 (6°. During the refinement of the structure, electron density peaks were located that were believed to be highly disordered solvent molecules (possibly diethyl ether. Attempts made to model the solvent molecule were not successful. The SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] option in PLATON indicated there was a large solvent cavity of 363 Å3. In the final cycles of refinement, this contribution of 117 electrons to the electron density was removed from the observed data. The density, the F(000 value, the molecular weight and the formula are given without taking into account the results obtained with SQUEEZE.

  13. 1,4,9,12-Tetramethoxy-14-octyl-5,8-dihydrodiindolo[3,2-b;2′,3′-h]carbazole with an unknown solvent

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    Norma Wrobel

    2017-03-01

    Full Text Available The title compound, 2C36H39N3O4·H2O, is a linear π-conjugated ladder oligomer with an alkyl chain on the central nitrogen atom. This diindolocarbazole, prepared via a twofold Cadogan reaction, adopts a sligthly convex shape, anti to the disordered octyl group. The unit cell contains nine molecules of the title compound and half a water molecule per main molecule. The water molecule forms hydrogen bridges, connecting the carbazole-NH and methoxy groups of different molecules. The crystal contains solvent molecules which are located in a channel parallel to the c axis. It was not possible to determine the position and nature of the solvent (a mixure of choroform, n-pentane and DMSO. The SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] option of PLATON was used to model the missing electron density. The given chemical formula and other crystal data do not take into account these solvent molecules.

  14. (E-4-[4-(Dimethylaminostyryl]-1-methylpyridin-1-ium tetrakis[(Z-4,4,4-trifluoro-3-oxo-1-(thiophen-2-ylbut-1-en-1-olato]gadolinate(III with an unknown amount of water as solvate

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    Da-Jun Wu

    2016-11-01

    Full Text Available In the complex anion of the title salt, (C16H19N2[Gd(C8H4F3S4], the GaIII cation is O,O′-chelated by four anionic 4,4,4-trifluoro-3-oxo-1-(thiophen-2-ylbut-1-en-1-olate ligands in a distorted square-antiprismatic geometry; the 4-[4-(dimethylaminostyryl]-1-methylpyridin-1-ium cation is nearly planar, with a dihedral angle of 9.6 (5° between the planes of the pyridine and benzene rings. In the crystal, the cations are linked with the complex anions via weak C—H...F and C—H...π interactions. Two of the four independent thiophene rings are disordered over two sites; occupancies were refined to 0.662 (10:0.338 (10. The solvent water molecules are highly disordered in a solvent-accessible void of 54 (3 Å3; the diffuse electron densities were removed from the data set using SQUEEZE [Spek (2015. Acta Cryst. C71, 9–16]. These solvent molecules are not considered in the given chemical formula and other crystal data.

  15. A new interpretation and practical aspects of the direct-methods modulus sum function. VIII.

    Science.gov (United States)

    Rius, Jordi; Torrelles, Xavier; Miravitlles, Carles; Amigó, J M; Reventós, M M

    2002-01-01

    Since the first publication of the direct-methods modulus sum function [Rius (1993). Acta Cryst. A49, 406-409], the application of this function to a variety of situations has been shown in a series of seven subsequent papers. In this way, much experience about this function and its practical use has been gained. It is thought by the authors that it is now the right moment to publish a more complete study of this function which also considers most of this practical knowledge. The first part of the study relates, thanks to a new interpretation, this function to other existing phase-refinement functions, while the second shows, with the help of test calculations on a selection of crystal structures, the behaviour of the function for two different control parameters. In this study, the principal interest is focused on the function itself and not on the optimization procedure which is based on a conventional sequential tangent formula refinement. The results obtained are quite satisfactory and seem to indicate that, when combined with more sophisticated optimization algorithms, the application field of this function could be extended to larger structures than those used for the test calculations.

  16. Application of δ recycling to electron automated diffraction tomography data from inorganic crystalline nanovolumes.

    Science.gov (United States)

    Rius, Jordi; Mugnaioli, Enrico; Vallcorba, Oriol; Kolb, Ute

    2013-07-01

    δ Recycling is a simple procedure for directly extracting phase information from Patterson-type functions [Rius (2012). Acta Cryst. A68, 399-400]. This new phasing method has a clear theoretical basis and was developed with ideal single-crystal X-ray diffraction data. On the other hand, introduction of the automated diffraction tomography (ADT) technique has represented a significant advance in electron diffraction data collection [Kolb et al. (2007). Ultramicroscopy, 107, 507-513]. When combined with precession electron diffraction, it delivers quasi-kinematical intensity data even for complex inorganic compounds, so that single-crystal diffraction data of nanometric volumes are now available for structure determination by direct methods. To check the tolerance of δ recycling to missing data-collection corrections and to deviations from kinematical behaviour of ADT intensities, δ recycling has been applied to differently shaped nanocrystals of various inorganic materials. The results confirm that it can phase ADT data very efficiently. In some cases even more complete structure models than those derived from conventional direct methods and least-squares refinement have been found. During this study it has been demonstrated that the Wilson-plot scaling procedure is largely insensitive to sample thickness variations and missing absorption corrections affecting electron ADT intensities.

  17. Direct phasing from Patterson syntheses by δ recycling.

    Science.gov (United States)

    Rius, Jordi

    2012-01-01

    The direct methods origin-free modulus sum function [Rius (1993). Acta Cryst. A49, 406-409] includes in its definition the structure factor G(Φ) of the squared crystal structure expressed in terms of Φ, the set of φ phases of the normalized structure factors E's of the crystal structure of unit-cell volume V. Here the simpler sum function variant S'(P) = ∑(H)E(-H)∫(V)δ(P,Δ)(Φ)exp(i2πHr)dV extended over all H reflections is introduced which involves no G's and in which the δ(P,Δ) function corresponds to δ(P) = FT(-1){(E(2)(H) - )exp[iφ(H)(Φ)]} (where FT = Fourier transform) with all values smaller than Δ = 2.5σ(P) equated to zero (σ(2)(P) is the variance of δ(P) calculable from the experimental intensities). The new phase estimates are obtained by Fourier transforming δ(P,Δ). This iterative phasing method (δ recycling) only requires calculation of Fourier transforms at two stages. Since δ(M) ≃ δ(P)/2, similar arguments are valid for δ(M) = FT(-1)[(E(H) - )exp(iφ(H))] from which the corresponding S'(M) phasing function follows.

  18. Crystal structures of spinel-type Na2MoO4 and Na2WO4 revisited using neutron powder diffraction

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    A. Dominic Fortes

    2015-06-01

    Full Text Available Time-of-flight neutron powder diffraction data have been collected from Na2MoO4 and Na2WO4 to a resolution of sin (θ/λ = 1.25 Å−1, which is substantially better than the previous analyses using Mo Kα X-rays, providing roughly triple the number of measured reflections with respect to the previous studies [Okada et al. (1974. Acta Cryst. B30, 1872–1873; Bramnik & Ehrenberg (2004. Z. Anorg. Allg. Chem. 630, 1336–1341]. The unit-cell parameters are in excellent agreement with literature data [Swanson et al. (1962. NBS Monograph No. 25, sect. 1, pp. 46–47] and the structural parameters for the molybdate agree very well with those of Bramnik & Ehrenberg (2004. However, the tungstate structure refinement of Okada et al. (1974 stands apart as being conspicuously inaccurate, giving significantly longer W—O distances, 1.819 (8 Å, and shorter Na—O distances, 2.378 (8 Å, than are reported here or in other simple tungstates. As such, this work represents an order-of-magnitude improvement in precision for sodium molybdate and an equally substantial improvement in both accuracy and precision for sodium tungstate. Both compounds adopt the spinel structure type. The Na+ ions have site symmetry .-3m and are in octahedral coordination while the transition metal atoms have site symmetry -43m and are in tetrahedral coordination.

  19. Cannabidiol revisited

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    Tobias Mayr

    2017-02-01

    Full Text Available The crystal structure of cannabidiol, C21H30O2, {systematic name: 2-[(1R,6R-3-methyl-6-(prop-1-en-2-ylcyclohex-2-enyl]-5-pentylbenzene-1,3-diol}, was determined earlier by Jones et al. [(1977. Acta Cryst. B33, 3211–3214] and Ottersen & Rosenqvist [(1977. Acta Chem. Scand. B31, 749–755]. In both investigations, the absolute configuration is given as R,R, referring to Mechoulam et al. [(1967.J. Am. Chem. Soc. 89, 4552–4554]. In the latter, the absolute configuration was identified by chemical means. Using the advantages of modern single-crystal X-ray diffractometers such as area detectors and high-intensity radiation sources, a high-quality structure determination including the absolute configuration was possible and is shown in this work. Furthermore, the rather uncommon Cu Kβ wavelength radiation was applied for the structure determination, which confirmed the absolute structure to be R,R.

  20. A monoclinic polymorph of [(Z-N-(3-chlorophenyl-O-methylthiocarbamato-κS](triphenylphosphane-κPgold(I: crystal structure and Hirshfeld surface analysis

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    Chien Ing Yeo

    2016-08-01

    Full Text Available The title compound, [Au(C8H7ClNOS(C18H15P], is a monoclinic (P21/n, Z′ = 1; form β polymorph of the previously reported triclinic form (P-1, Z′ = 1; form α [Tadbuppa & Tiekink (2010. Acta Cryst. E66, m664]. The molecular structures of both forms feature an almost linear gold(I coordination geometry [P—Au—S = 175.62 (5° in the title polymorph], being coordinated by thiolate S and phosphane P atoms, a Z conformation about the C=N bond and an intramolecular Au...O contact. The major conformational difference relates to the relative orientations of the residues about the Au—S bond: the P—Au—S—C torsion angles are −8.4 (7 and 106.2 (7° in forms α and β, respectively. The molecular packing of form β features centrosymmetric aggregates sustained by aryl-C—H...O interactions, which are connected into a three-dimensional network by aryl-C—H...π contacts. The Hirshfeld analysis of forms α and β shows many similarities with the notable exception of the influence of C—H...O interactions in form β.

  1. Oscillatory thermocapillary convection in liquid bridges with highly deformed free surfaces: Experiments and energy-stability analysis

    Science.gov (United States)

    Sumner, L. B. S.; Neitzel, G. P.; Fontaine, J.-P.; Dell'Aversana, P.

    2001-01-01

    Laboratory experimentation, numerical simulation, and energy-stability theory are used to examine the effect of interface deformation on the onset of oscillatory thermocapillary convection in half zones. Experiments are performed to map the stability boundaries marking the onset of oscillatory flow, modifying the free-surface deformation by adjusting the volume of liquid in the bridge. The stability results presented here along with those of other researchers [Monti et al., Proceedings of the 43rd Cong. Int. Artro. Fed. (1992); Hu et al., J. Cryst. Growth 142, 379 (1994)] show that free-surface curvature can have a pronounced influence on flow stability. Steady, axisymmetric flow simulations are computed using the commercial code FIDAP to model the conditions of the experiments, and reveal that flow structure near the stability boundary is sensitive to several parameters. Energy theory is applied to these simulations to determine sufficient conditions for stability. Comparisons between the theoretical and experimental results show nonconservative energy limits falling above the experimentally determined stability boundaries for bridges of various liquid volumes. While the trend of the experimental data is predicted for zones of large volume ratio (bulging zones), the same cannot be said for those with small volume ratio (necked-down zones). In addition, energy-stability limits for some undeformed-free-surface cases were determined which are above the linear-stability limits determined by other researchers, in clear contradiction of the roles of the respective theories.

  2. Ring-strain release in neutral and dicationic 7,8,17,18-tetrabromo-5,10,15,20-tetraphenylporphyrin: crystal structures of C44H26Br4N4 and C44H28Br4N42+·2ClO4−·3CH2Cl2

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    W. Robert Scheidt

    2016-06-01

    Full Text Available Two porphyrin complexes were studied to determine the effects of protonation on ring deformation within the porphyrin. The porphyrin 7,8,17,18-tetrabromo-5,10,15,20-tetraphenylporphyrin, C44H26Br4N4, was selected because the neutral species is readily doubly protonated to yield a dication, which was crystallized here with perchlorate counter-ions as a dichloromethane trisolvate, C44H28Br4N42+·2ClO4−·3CH2Cl2. The centrosymmetric neutral species is observed to have a mild `ruffling' of the pyrrole rings and is essentially planar throughout; intramolecular N—H...N hydrogen bonds occur. In contrast, the dication exhibits considerable deformation, with the pyrrole rings oriented well out of the plane of the porphyrin, resulting in a `saddle' conformation of the ring. The charged species forms N—H...O hydrogen bonds to the perchlorate anions, which lie above and below the plane of the porphyrin ring. Distortions to the planarity of the pyrrole rings in both cases are very minor. The characterization of the neutral species represents a low-temperature redetermination of the previous room-temperature analyses [Zou et al. (1995. Acta Cryst. C51, 760–761; Rayati et al. (2008. Polyhedron, pp. 2285–2290], which showed disorder and physically unrealistic displacement parameters.

  3. Mol-ecular and crystal structure of gossypol tetra-methyl ether with an unknown solvate.

    Science.gov (United States)

    Honkeldieva, Muhabbat; Talipov, Samat; Mardanov, Rustam; Ibragimov, Bakhtiyar

    2015-02-01

    The title compound, C34H38O8 (systematic name: 5,5'-diisopropyl-2,2',3,3'-tetra-meth-oxy-7,7'-dimethyl-2H,2'H-8,8'-bi-[naphtho-[1,8-bc]furan]-4,4'-diol), has been obtained from a gossypol solution in a mixture of dimethyl sulfate and methanol. The mol-ecule is situated on a twofold rotation axis, so the asymmetric unit contains one half-mol-ecule. In the mol-ecule, the hy-droxy groups are involved in intra-molecular O-H⋯O hydrogen bonds, and the two naphthyl fragments are inclined each to other by 83.8 (1)°. In the crystal, weak C-H⋯O and C-H⋯π inter-actions consolidate the packing, which exhibits channels with an approximate diameter of 6 Å extending along the c-axis direction. These channels are filled with highly disordered solvent mol-ecules, so their estimated scattering contribution was subtracted from the observed diffraction data using the SQUEEZE option in PLATON [Spek, A. L. (2015). Acta Cryst. C71, 9-18].

  4. Crystal structure of cis-bis-{4-phenyl-1-[(3R)-1,7,7-tri-methyl-2-oxobi-cyclo-[2.2.1]heptan-3-ylidene]thio-semicarbazidato-κ(3) O,N (1),S}cadmium(II) with an unknown solvent mol-ecule.

    Science.gov (United States)

    Nogueira, Vanessa Senna; Bresolin, Leandro; Näther, Christian; Jess, Inke; de Oliveira, Adriano Bof

    2015-12-01

    The reaction between the racemic mixture of the camphor-4-phenyl-thio-semicarbazone derivative and cadmium acetate dihydrate yielded the title compound, [Cd(C17H20N3OS)2]. The Cd(II) ion is six-coordinated in a distorted octa-hedral environment by two deprotonated thio-semicarbazone ligands acting as an O,N,S-donor in a tridentate chelating mode, forming five-membered chelate rings. In the crystal, the mol-ecules are connected via pairs of N-H⋯S and C-H⋯S inter-actions, building centrosymmetric dimers. One of the ligands is disordered in the campher unit over two sets of sites with site-occupancy factors of 0.7 and 0.3. The structure contains additional solvent mol-ecules, which are disordered and for which no reasonable split model was found. Therefore, the data were corrected for disordered solvent using the SQUEEZE routine [Spek (2015 ▸). Acta Cryst. C71, 9-18] in PLATON. Since the disordered solvents were removed by data processing, and the number of solvent entities was a suggestion only, they were not considered in the chemical formula and subsequent chemical or crystal information.

  5. Experimental and theoretical study of diffraction properties of various crystals for the realization of a soft gamma-ray Laue lens

    CERN Document Server

    Barriere, Nicolas; von Ballmoos, Peter; Abrosimov, Nikolai V; Courtois, Pierre; Bastie, Pierre; Camus, Thierry; Jentschel, Michael; Kurlov, Vladimir N; Natalucci, Lorenzo; Roudil, Gilles; Brejnholt, Nicolai Frisch; Serre, Denis

    2009-01-01

    Crystals are the elementary constituents of Laue lenses, an emerging technology which could allow the realization of a space borne telescope 10 to 100 times more sensitive than existing ones in the 100 keV - 1.5 MeV energy range. This study addresses the current endeavor to the development of efficient crystals for the realization of a Laue lens. In the theoretical part 35 candidate-crystals both pure and two-components are considered. Their peak reflectivity at 100 keV, 500 keV and 1 MeV is calculated assuming they are mosaic crystals. It results that a careful selection of crystals can allow a reflectivity above 30% over the whole energy range, and even reaching 40% in its lower part. Experimentally, we concentrated on three different materials (Si_{1-x}Ge_x with gradient of composition, mosaic Cu and Au) that have been measured both at ESRF and ILL using highly-monochromatic beams ranging from 300 keV up to 816 keV. The aim was to check their homogeneity, quality and angular spread (mosaicity). These cryst...

  6. A Hidden Markov model web application for analysing bacterial genomotyping DNA microarray experiments.

    Science.gov (United States)

    Newton, Richard; Hinds, Jason; Wernisch, Lorenz

    2006-01-01

    Whole genome DNA microarray genomotyping experiments compare the gene content of different species or strains of bacteria. A statistical approach to analysing the results of these experiments was developed, based on a Hidden Markov model (HMM), which takes adjacency of genes along the genome into account when calling genes present or absent. The model was implemented in the statistical language R and applied to three datasets. The method is numerically stable with good convergence properties. Error rates are reduced compared with approaches that ignore spatial information. Moreover, the HMM circumvents a problem encountered in a conventional analysis: determining the cut-off value to use to classify a gene as absent. An Apache Struts web interface for the R script was created for the benefit of users unfamiliar with R. The application may be found at http://hmmgd.cryst.bbk.ac.uk/hmmgd. The source code illustrating how to run R scripts from an Apache Struts-based web application is available from the corresponding author on request. The application is also available for local installation if required.

  7. Redetermination of diaqua[N,N′-bis(3-methoxy-2-oxidobenzylideneethylenediamine-κ4O,N,N′,O′]manganese(III perchlorate at 100 K

    Directory of Open Access Journals (Sweden)

    Shabana Noor

    2016-11-01

    Full Text Available The crystal structure of the organic–inorganic title salt, [Mn(C18H18N2O4(H2O2]ClO4, has been redetermined at 100 K. In contrast to the crystal structure determinations at room temperature [Akitsu et al. (2005. Acta Cryst. C61, m324–m328; Bermejo et al. (2007. Eur. J. Inorg. Chem. pp. 3789–3797], positional disorder of the ethylene bridge in the Schiff base ligand and the perchlorate anion is not observed at 100 K. The MnIII ion is six-coordinated with the tetradentate Schiff base chelate ligand N,N′-bis(3-methoxy-2-oxybenzylideneethylenediamine occupying coordination sites in the equatorial plane and the aqua ligands residing in the two axial positions. The octahedral coordination sphere of the MnIII ion exhibits an axial elongation due to the Jahn–Teller effect, which is characteristic of a d4 high-spin electronic configuration.

  8. Azimuthal anchoring of a nematic liquid crystal on a grooved interface with anisotropic polar anchoring

    Institute of Scientific and Technical Information of China (English)

    Zhou Xuan; Zhang Zhi-Dong; Ye Wen-Jiang; Xuan Li

    2012-01-01

    Zhang Y Jet al.[Zhang Y J,Zhang Z D,Zhu L Z and Xuan L 2011 Liquid Cryst.38 355] investigated the effects of finite polar anchoring on the azimuthal anchoring energy at a grooved interface,in which polar anchoring was isotropic in the local tangent plane of the surface.In this paper,we investigate the effects of both isotropic and anisotropic polar anchoring on the surface anchoring energy in the frame of Fukuda et al.'s theory.The results show that anisotropic polar anchoring strengthens the azimuthal anchoring of grooved surfaces.In the one-elastic-constant approximation (K11 =K22 =K33 =K),the surface-groove-induced azimuthal anchoring energy is entirely consistent with the result of Faetti,and it reduces to the original result of Berreman with an increase in polar anchoring.Moreover,the contribution of the surface-like elastic term to the Rapini-Papoular anchoring energy is zero.

  9. Crystal structure of lead(II) tartrate: a redetermination.

    Science.gov (United States)

    Weil, Matthias

    2015-01-01

    Single crystals of poly[μ4-tartrato-κ(6) O (1),O (3):O (1'):O (2),O (4):O (4')-lead], [Pb(C4H4O6)] n , were grown in a gel medium. In comparison with the previous structure determination of this compound from laboratory powder X-ray diffraction data [De Ridder et al. (2002 ▶). Acta Cryst. C58, m596-m598], the redetermination on the basis of single-crystal data reveals the absolute structure, all atoms with anisotropic displacement parameters and a much higher accuracy in terms of bond lengths and angles. It could be shown that a different space group or incorporation of water as reported for similarly gel-grown lead tartrate crystals is incorrect. In the structure, each Pb(2+) cation is bonded to eight O atoms of five tartrate anions, while each tartrate anion links four Pb(2+) cations. The resulting three-dimensional framework is stabilized by O-H⋯O hydrogen bonds between the OH groups of one tartrate anion and the carboxyl-ate O atoms of adjacent anions.

  10. Inferring planar disorder in close-packed structures via ε-machine spectral reconstruction theory: examples from simulated diffraction patterns.

    Science.gov (United States)

    Varn, D P; Canright, G S; Crutchfield, J P

    2013-07-01

    A previous paper detailed a novel algorithm, ε-machine spectral reconstruction theory (εMSR), that infers pattern and disorder in planar-faulted, close-packed structures directly from X-ray diffraction patterns [Varn et al. (2013). Acta Cryst. A69, 197-206]. Here εMSR is applied to simulated diffraction patterns from four close-packed crystals. It is found that, for stacking structures with a memory length of three or less, εMSR reproduces the statistics of the stacking structure; the result being in the form of a directed graph called an ε-machine. For stacking structures with a memory length larger than three, εMSR returns a model that captures many important features of the original stacking structure. These include multiple stacking faults and multiple crystal structures. Further, it is found that εMSR is able to discover stacking structure in even highly disordered crystals. In order to address issues concerning the long-range order observed in many classes of layered materials, several length parameters are defined, calculable from the ε-machine, and their relevance is discussed.

  11. 2,3-Dibromo-3-phenylpropanoic acid: a monoclinic polymorph

    Directory of Open Access Journals (Sweden)

    Trent R. Howard

    2016-11-01

    Full Text Available Bromination of trans-cinnamic acid resulted in the formation of 2,3-dibromo-3-phenylpropanoic acid, C9H8Br2O2. Crystallization from ethanol–water (1:1 gave crystals of different shapes. One is in the form of rods, that crystallized as the orthorhombic polymorph (Pnma, and whose structure has been described [Thong et al. (2008. Acta Cryst. E64, o1946]. The other are thin plate-like crystals which are the monoclinic polymorph (P21/n. The structure of this monoclinic polymorph is similar to that of the orthorhombic polymorph; here the aliphatic C atoms are disordered over three sets of sites (occupancy ratio 0.5:0.25:0.25. In the crystal, molecules are linked by pairs of O—H...O hydrogen bonds, forming inversion dimers with an R22(8 ring motif. The dimers are linked by weak C—H...Br hydrogen bonds, forming chains propagating along the a-axis direction.

  12. A polymorph structure of copper(II hydrogenphosphite dihydrate

    Directory of Open Access Journals (Sweden)

    Lei Yang

    2009-04-01

    Full Text Available The title compound, poly[[diaquacopper(II]-μ3-hydrogenphosphito], [Cu(HPO3(H2O2]n, (I, has been prepared by hydrothermal synthesis at 393 K. Its non-centrosymmetric polymorph structure, (II, was known previously and has been redetermined at 193 (2 K [El Bali & Massa (2002. Acta Cryst. E58, i29–i31]. The Cu atoms in (I and (II are square-pyramidal coordinated. A distorted octahedral geometry around the Cu atoms is considered by including the strongly elongated apical distances of 2.8716 (15 Å in (I and 3.000 (1 Å in (II. The Cu...Cu separation of the dimeric unit is 3.1074 (3 Å. The secondary building units (SBU (the Cu2O2 dimer and two HPO3 units in (I are inversion related and form a two-dimensional layered structure, with sheets parallel to the bc plane, whereas in the structure of (II, the chain elements are connected via screw-axis symmetry to form a three-dimensional microporous framework. In both polymorph structures, strong O—H...O hydrogen bonds are observed.

  13. Di-n-butylammonium 2-[(3,5-di-tert-butyl-4-hydroxybenzylsulfanyl]benzoate

    Directory of Open Access Journals (Sweden)

    Abeer A. Alhadi

    2010-09-01

    Full Text Available The title salt, C8H20N+·C22H27O3S−, is a proton-transfer compound derived from the recently reported parent carboxylic acid [Alhadi et al. (2010. Acta Cryst. E66, o1787] by the addition of a second equivalent of di-n-butylamine, yielding the di-n-butylammonium carboxylate salt. The structure of the carboxylate anion resembles that of the parent carboxylic acid. The main difference lies in the position of the H atom in the 4-hydroxy group. In the anion the O—H bond is perpendicular, rather than parallel, to the benzyl ring. This position appears to facilitate hydrogen bonding to an O atom of the carboxylate group of a symmetry-related anion. In addition, there are three N—H...O hydrogen bonds. In contrast, the neutral species hydrogen bonds via a carboxylic acid dimer. The dihedral angle between the benzene rings in the anion is 79.19 (7°.

  14. PCDDB: new developments at the Protein Circular Dichroism Data Bank.

    Science.gov (United States)

    Whitmore, Lee; Miles, Andrew John; Mavridis, Lazaros; Janes, Robert W; Wallace, B A

    2017-01-04

    The Protein Circular Dichroism Data Bank (PCDDB) has been in operation for more than 5 years as a public repository for archiving circular dichroism spectroscopic data and associated bioinformatics and experimental metadata. Since its inception, many improvements and new developments have been made in data display, searching algorithms, data formats, data content, auxillary information, and validation techniques, as well as, of course, an increase in the number of holdings. It provides a site (http://pcddb.cryst.bbk.ac.uk) for authors to deposit experimental data as well as detailed information on methods and calculations associated with published work. It also includes links for each entry to bioinformatics databases. The data are freely available to accessors either as single files or as complete data bank downloads. The PCDDB has found broad usage by the structural biology, bioinformatics, analytical and pharmaceutical communities, and has formed the basis for new software and methods developments. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Circular dichroism spectral data and metadata in the Protein Circular Dichroism Data Bank (PCDDB): a tutorial guide to accession and deposition.

    Science.gov (United States)

    Janes, Robert W; Miles, A J; Woollett, B; Whitmore, L; Klose, D; Wallace, B A

    2012-09-01

    The Protein Circular Dichroism Data Bank (PCDDB) is a web-based resource containing circular dichroism (CD) and synchrotron radiation circular dichroism spectral and associated metadata located at http://pcddb.cryst.bbk.ac.uk. This resource provides a freely available, user-friendly means of accessing validated CD spectra and their associated experimental details and metadata, thereby enabling broad usage of this material and new developments across the structural biology, chemistry, and bioinformatics communities. The resource also enables researchers utilizing CD as an experimental technique to have a means of storing their data at a secure site from which it is easily retrievable, thereby making their results publicly accessible, a current requirement of many grant-funding agencies world-wide, as well as meeting the data-sharing requirements for journal publications. This tutorial provides extensive information on searching, accessing, and downloading procedures for those who wish to utilize the data available in the data bank, and detailed information on deposition procedures for creating and validating entries, including comprehensive explanations of their contents and formats, for those who wish to include their data in the data bank. Copyright © 2012 Wiley Periodicals, Inc.

  16. Crystal structure of ethyl 3-amino-6-methyl-2-[(4-methyl­phen­yl)carbamo­yl]-4-[(E)-2-phenyl­ethen­yl]thieno[2,3-b]pyridine-5-carboxyl­ate monohydrate

    Science.gov (United States)

    Mague, Joel T.; Akkurt, Mehmet; Mohamed, Shaaban K.; Bakhite, Etify A.; Albayati, Mustafa R.

    2016-01-01

    In the title mol­ecule, C27H25N3O3S·H2O, the dihedral angle between the planes of the thienyl ring and the pendant p-tolyl group is 39.25 (6)°, while that between the pyridine ring and the pendant phenyl ring is 44.37 (6)°. In addition, there is a slight twist in the bicyclic core, with a dihedral angle of 2.39 (4)° between the thienyl and pyridine rings. The conformation of the carbamoyl moiety is partially determined by an intra­molecular N—H⋯O hydrogen bond. In the crystal, complementary N—H⋯O hydrogen bonds form dimers which are then associated into chains parallel to the c axis through O—H⋯N hydrogen bonds involving the water mol­ecule of crystallization. Electron density associated with an additional solvent mol­ecule of partial occupancy and disordered about a twofold axis was removed with the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s). PMID:27006791

  17. A Fourier transform method for powder diffraction based on the Debye scattering equation.

    Science.gov (United States)

    Thomas, Noel William

    2011-11-01

    A fast Fourier transform algorithm is introduced into the method recently defined for calculating powder diffraction patterns by means of the Debye scattering equation (DSE) [Thomas (2010). Acta Cryst. A66, 64-77]. For this purpose, conventionally used histograms of interatomic distances are replaced by compound transmittance functions. These may be Fourier transformed to partial diffraction patterns, which sum to give the complete diffraction pattern. They also lead to an alternative analytical expression for the DSE sum, which reveals its convergence behaviour. A means of embedding the DSE approach within the reciprocal-lattice-structure-factor method is indicated, with interpolation methods for deriving the peak profiles of nanocrystalline materials outlined. Efficient calculation of transmittance functions for larger crystallites requires the Patterson group symmetry of the crystals to be taken into account, as shown for α- and β-quartz. The capability of the transmittance functions to accommodate stacking disorder is demonstrated by reference to kaolinite, with a fully analytical treatment of disorder described. Areas of future work brought about by these developments are discussed, specifically the handling of anisotropic atomic displacement parameters, inverse Fourier transformation and the incorporation of instrumental (diffractometer) parameters.

  18. 4-De­oxy-4-fluoro-β-d-gluco­pyranose

    Science.gov (United States)

    Zhang, Wenhui; Oliver, Allen G.; Serianni, Anthony S.

    2010-01-01

    4-De­oxy-4-fluoro-β-d-glucopyran­ose, C6H11FO5, (I), crystallizes from water at room temperature in a slightly distorted 4 C 1 chair con­formation. The observed chair distortion differs from that observed in β-d-glucopyran­ose [Kouwijzer, van Eijck, Kooijman & Kroon (1995 ▶). Acta Cryst. B51, 209–220], (II), with the former skewed toward a B C3,O5 (boat) conformer and the latter toward an O5 TB C2 (twist–boat) conformer, based on Cremer–Pople analysis. The exocyclic hy­droxy­methyl group conformations in (I) and (II) are similar; in both cases, the O—C—C—O torsion angle is ∼−60° (gg con­former). Inter­molecular hydrogen bonding in the crystal structures of (I) and (II) is conserved in that identical patterns of donors and acceptors are observed for the exocyclic substituents and the ring O atom of each monosaccharide. Inspection of the crystal packing structures of (I) and (II) reveals an essentially identical packing configuration. PMID:20921614

  19. 4-Deoxy-4-fluoro-β-D-glucopyranose.

    Science.gov (United States)

    Zhang, Wenhui; Oliver, Allen G; Serianni, Anthony S

    2010-10-01

    4-Deoxy-4-fluoro-β-D-glucopyranose, C(6)H(11)FO(5), (I), crystallizes from water at room temperature in a slightly distorted (4)C(1) chair conformation. The observed chair distortion differs from that observed in β-D-glucopyranose [Kouwijzer, van Eijck, Kooijman & Kroon (1995). Acta Cryst. B51, 209-220], (II), with the former skewed toward a B(C3,O5) (boat) conformer and the latter toward an (O5)TB(C2) (twist-boat) conformer, based on Cremer-Pople analysis. The exocyclic hydroxymethyl group conformations in (I) and (II) are similar; in both cases, the O-C-C-O torsion angle is ∼-60° (gg conformer). Intermolecular hydrogen bonding in the crystal structures of (I) and (II) is conserved in that identical patterns of donors and acceptors are observed for the exocyclic substituents and the ring O atom of each monosaccharide. Inspection of the crystal packing structures of (I) and (II) reveals an essentially identical packing configuration.

  20. Molecular architecture of the nucleoprotein C-terminal domain from the Ebola and Marburg viruses.

    Science.gov (United States)

    Baker, Laura E; Ellena, Jeffrey F; Handing, Katarzyna B; Derewenda, Urszula; Utepbergenov, Darkhan; Engel, Daniel A; Derewenda, Zygmunt S

    2016-01-01

    The Filoviridae family of negative-sense, single-stranded RNA (ssRNA) viruses is comprised of two species of Marburgvirus (MARV and RAVV) and five species of Ebolavirus, i.e. Zaire (EBOV), Reston (RESTV), Sudan (SUDV), Taï Forest (TAFV) and Bundibugyo (BDBV). In each of these viruses the ssRNA encodes seven distinct proteins. One of them, the nucleoprotein (NP), is the most abundant viral protein in the infected cell and within the viral nucleocapsid. It is tightly associated with the viral RNA in the nucleocapsid, and during the lifecycle of the virus is essential for transcription, RNA replication, genome packaging and nucleocapsid assembly prior to membrane encapsulation. The structure of the unique C-terminal globular domain of the NP from EBOV has recently been determined and shown to be structurally unrelated to any other known protein [Dziubańska et al. (2014), Acta Cryst. D70, 2420-2429]. In this paper, a study of the C-terminal domains from the NP from the remaining four species of Ebolavirus, as well as from the MARV strain of Marburgvirus, is reported. As expected, the crystal structures of the BDBV and TAFV proteins show high structural similarity to that from EBOV, while the MARV protein behaves like a molten globule with a core residual structure that is significantly different from that of the EBOV protein.

  1. Validation of experimental molecular crystal structures with dispersion-corrected density functional theory calculations.

    Science.gov (United States)

    van de Streek, Jacco; Neumann, Marcus A

    2010-10-01

    This paper describes the validation of a dispersion-corrected density functional theory (d-DFT) method for the purpose of assessing the correctness of experimental organic crystal structures and enhancing the information content of purely experimental data. 241 experimental organic crystal structures from the August 2008 issue of Acta Cryst. Section E were energy-minimized in full, including unit-cell parameters. The differences between the experimental and the minimized crystal structures were subjected to statistical analysis. The r.m.s. Cartesian displacement excluding H atoms upon energy minimization with flexible unit-cell parameters is selected as a pertinent indicator of the correctness of a crystal structure. All 241 experimental crystal structures are reproduced very well: the average r.m.s. Cartesian displacement for the 241 crystal structures, including 16 disordered structures, is only 0.095 Å (0.084 Å for the 225 ordered structures). R.m.s. Cartesian displacements above 0.25 A either indicate incorrect experimental crystal structures or reveal interesting structural features such as exceptionally large temperature effects, incorrectly modelled disorder or symmetry breaking H atoms. After validation, the method is applied to nine examples that are known to be ambiguous or subtly incorrect.

  2. Crystal structures of two ytterbium(III) complexes comprising alkynylamidinate ligands.

    Science.gov (United States)

    Wang, Sida; Sroor, Farid M; Liebing, Phil; Lorenz, Volker; Hilfert, Liane; Edelmann, Frank T

    2016-09-01

    Two ytterbium(III) complexes comprising alkynylamidinate ligands, namely bis-(η(5)-cyclo-penta-dien-yl)(3-cyclo-propyl-N,N'-diiso-propyl-propynamidinato-κ(2)N,N')ytterbium(III), [Yb(C5H5)2(C12H19N2)] or Cp2Yb[( (i) Pr2N)2C-C≡C-c-C3H5] (1) and tris-(3-phenyl-N,N'-di-cyclo-hexyl-propynamidinato-κ(2)N,N')ytterbium(III), [Yb(C21H27N2)3] or Yb[(CyN)2C-C≡C-Ph]3 (Cy = cyclo-hex-yl) (2) have been synthesized and structurally characterized. Both complexes are monomers; for complex 2, the contribution to the scattering from highly disordered toluene solvent molecules in these voids was removed with the SQUEEZE routine [Spek (2015). Acta Cryst. C71, 9-18] in PLATON. The stated crystal data for Mr, μ etc. do not take these into account.

  3. Crystal structure of Sc1.91In1.39Mo15Se19, containing Mo6 and Mo9 clusters

    Directory of Open Access Journals (Sweden)

    Patrick Gougeon

    2015-07-01

    Full Text Available The structure of scandium indium pentadecamolybdenum nonadecaselenide, Sc1.91In1.39Mo15Se19, is isotypic with In2.9Mo15Se19 [Grüttner et al. (1979. Acta Cryst. B35, 285–292]. It is characterized by two cluster units Mo6Sei8Sea6 and Mo9Sei11Sea6 (where i represents inner and a apical atoms that are present in a 1:1 ratio. The cluster units are centered at Wyckoff positions 2b and 2c and have point-group symmetry -3 and -6, respectively. The clusters are interconnected through additional Mo—Se bonds. Sc—Se and In—Se bonds complete the structural set-up. In the title compound, the Sc3+ cations replace the trivalent indium atoms present in In2.9Mo15Se19, and a deficiency is observed at the monovalent indium site. One Mo, one Se and the Sc atom are situated on mirror planes, whereas two other Se atoms and the In atom are situated on threefold rotation axes.

  4. Na3.88Mo15Se19: a novel ternary reduced molybdenum selenide containing Mo6 and Mo9 clusters

    Directory of Open Access Journals (Sweden)

    Diala Salloum

    2013-10-01

    Full Text Available The structure of tetrasodium pentadecamolybdenum nonadecaselenide, Na3.88Mo15Se19, is isotypic with the In3+xMo15Se19 compounds [Grüttner et al. (1979. Acta Cryst. B35, 285–292]. It is characterized by two cluster units, Mo6Sei8Sea6 and Mo9Sei11Sea6 (where i represents inner and a apical atoms, that are present in a 1:1 ratio. The cluster units are centered at Wyckoff positions 2b and 2c and have point-group symmetry -3 and -6, respectively. The clusters are interconnected through additional Mo—Se bonds. In the title compound, the Na+ cations replace the trivalent as well as the monovalent indium atoms present in In3.9Mo15Se19. One Mo, one Se and one Na atom are situated on mirror planes, and two other Se atoms and one Na atom [occupancy 0.628 (14] are situated on threefold rotation axes. The crystal studied was twinned by merohedry with refined components of 0.4216 (12 and 0.5784 (12.

  5. Protein energy landscapes determined by five-dimensional crystallography.

    Science.gov (United States)

    Schmidt, Marius; Srajer, Vukica; Henning, Robert; Ihee, Hyotcherl; Purwar, Namrta; Tenboer, Jason; Tripathi, Shailesh

    2013-12-01

    Free-energy landscapes decisively determine the progress of enzymatically catalyzed reactions [Cornish-Bowden (2012), Fundamentals of Enzyme Kinetics, 4th ed.]. Time-resolved macromolecular crystallography unifies transient-state kinetics with structure determination [Moffat (2001), Chem. Rev. 101, 1569-1581; Schmidt et al. (2005), Methods Mol. Biol. 305, 115-154; Schmidt (2008), Ultrashort Laser Pulses in Medicine and Biology] because both can be determined from the same set of X-ray data. Here, it is demonstrated how barriers of activation can be determined solely from five-dimensional crystallography, where in addition to space and time, temperature is a variable as well [Schmidt et al. (2010), Acta Cryst. A66, 198-206]. Directly linking molecular structures with barriers of activation between them allows insight into the structural nature of the barrier to be gained. Comprehensive time series of crystallographic data at 14 different temperature settings were analyzed and the entropy and enthalpy contributions to the barriers of activation were determined. One hundred years after the discovery of X-ray scattering, these results advance X-ray structure determination to a new frontier: the determination of energy landscapes.

  6. Raster-scanning serial protein crystallography using micro- and nano-focused synchrotron beams.

    Science.gov (United States)

    Coquelle, Nicolas; Brewster, Aaron S; Kapp, Ulrike; Shilova, Anastasya; Weinhausen, Britta; Burghammer, Manfred; Colletier, Jacques Philippe

    2015-05-01

    High-resolution structural information was obtained from lysozyme microcrystals (20 µm in the largest dimension) using raster-scanning serial protein crystallography on micro- and nano-focused beamlines at the ESRF. Data were collected at room temperature (RT) from crystals sandwiched between two silicon nitride wafers, thereby preventing their drying, while limiting background scattering and sample consumption. In order to identify crystal hits, new multi-processing and GUI-driven Python-based pre-analysis software was developed, named NanoPeakCell, that was able to read data from a variety of crystallographic image formats. Further data processing was carried out using CrystFEL, and the resultant structures were refined to 1.7 Å resolution. The data demonstrate the feasibility of RT raster-scanning serial micro- and nano-protein crystallography at synchrotrons and validate it as an alternative approach for the collection of high-resolution structural data from micro-sized crystals. Advantages of the proposed approach are its thriftiness, its handling-free nature, the reduced amount of sample required, the adjustable hit rate, the high indexing rate and the minimization of background scattering.

  7. Tetrakis(μ2-2,2-dimethylpropanoato-κ2O,O′bis[(pyridine-κNcopper(II]: a monoclinic polymorph

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    Lailatun Nazirah Ozair

    2010-05-01

    Full Text Available The structure of the dinuclear title complex, [Cu2(C5H9O24(C5H5N2], represents a monoclinic polymorph of the previously reported triclinic form [Blewett et al. (2006. Acta Cryst. E62, m420–m422]. Each carboxylate group is bidentate bridging and the distorted octahedral geometry about each CuII atom is completed by a pyridine N atom and the other Cu atom [Cu...Cu = 2.6139 (7 Å]. In the crystal, molecules are connected into supramolecular chains via π–π interactions formed by the pyridine rings [centroid–centroid distance = 3.552 (3 Å] and these are connected into a two-dimensional array in the ac plane by C—H...π contacts. One of the tert-butyl groups is disordered over two orientations in a 0.734 (6:0.266 (6 ratio.

  8. Crystal structure of a new monoclinic polymorph of N-(4-methylphenyl-3-nitropyridin-2-amine

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    Aina Mardia Akhmad Aznan

    2014-08-01

    Full Text Available The title compound, C12H11N3O2, is a second monoclinic polymorph (P21, with Z′ = 4 of the previously reported monoclinic (P21/c, with Z′ = 2 form [Akhmad Aznan et al. (2010. Acta Cryst. E66, o2400]. Four independent molecules comprise the asymmetric unit, which have the common features of a syn disposition of the pyridine N atom and the toluene ring, and an intramolecular amine–nitro N—H...O hydrogen bond. The differences between molecules relate to the dihedral angles between the rings which range from 2.92 (19 to 26.24 (19°. The geometry-optimized structure [B3LYP level of theory and 6–311 g+(d,p basis set] has the same features except that the entire molecule is planar. In the crystal, the three-dimensional architecture is consolidated by a combination of C—H...O, C—H...π, nitro-N—O...π and π–π interactions [inter-centroid distances = 3.649 (2–3.916 (2 Å].

  9. Crystal structure of 2-bromobenzoic acid at 120 K: a redetermination

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    Kornelia Kowalska

    2014-10-01

    Full Text Available The crystal structure of the title compound, C7H5BrO2, was originally studied using photographic data at room temperature with Cu Kα radiation [Ferguson & Sim (1962. Acta Cryst. 15, 346–350]. The present study was undertaken at 120 K with a CCD diffractometer using Cu Kα radiation, and resulted in improved geometrical parameters. In the molecule, the carboxy group is inclined to the benzene ring by 18.7 (2° and there is a close intramolecular Br...O contact of 3.009 (3 Å. In the crystal, molecules are linked by pairs of O—H...O hydrogen bonds, forming inversion dimers with the classical R22(8 ring motif for carboxylic acids. Neighbouring dimers are linked by weak C—H...O hydrogen bonds, forming tapes propagating in [1-10]. Adjacent tapes interact by slipped parallel π–π interactions [inter-centroid distance = 3.991 (2, interplanar distance = 3.509 (2 Å, slippage = 1.900 Å] to form columns approximately along the b-axis direction. Neighbouring columns interact dispersively, forming a three-dimensional framework structure.

  10. 2,2′-(Piperazine-1,4-diyldiethanaminium dibenzoate

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    Ignacy Cukrowski

    2012-08-01

    Full Text Available The asymmetric unit of the title salt C8H22N42+·2C7H5O2−, comprises two independent pairs of half a 2,2′-(piperazine-1,4-diyldiethanaminium dication plus a benzoate anion. The dications are symmetrical and lie across crystallographic centres of inversion. The crystal structure was refined as a two-component pseudo-merohedral twin using the twin law 001 0-10 100 [he domain fractions are 0.8645 (8 and 0.1355 (8]. The anions and cations are linked by N—H...O hydrogen bonds and weak N—H...O intermolecular interactions to form infinite two-dimensional networks parallel to [101]. The conformation adopted by the cation in the crystal structure is very similar to that adopted by the same cation in the structures of the 2-hydroxybenzoate [Cukrowski et al. (2012. Acta Cryst, E68, o2387], the nitrate and the tetrahydrogen pentaborate salts.

  11. Crystal structure of ethyl 3-amino-6-methyl-2-[(4-methyl-phen-yl)carbamo-yl]-4-[(E)-2-phenyl-ethen-yl]thieno[2,3-b]pyridine-5-carboxyl-ate monohydrate.

    Science.gov (United States)

    Mague, Joel T; Akkurt, Mehmet; Mohamed, Shaaban K; Bakhite, Etify A; Albayati, Mustafa R

    2016-03-01

    In the title mol-ecule, C27H25N3O3S·H2O, the dihedral angle between the planes of the thienyl ring and the pendant p-tolyl group is 39.25 (6)°, while that between the pyridine ring and the pendant phenyl ring is 44.37 (6)°. In addition, there is a slight twist in the bicyclic core, with a dihedral angle of 2.39 (4)° between the thienyl and pyridine rings. The conformation of the carbamoyl moiety is partially determined by an intra-molecular N-H⋯O hydrogen bond. In the crystal, complementary N-H⋯O hydrogen bonds form dimers which are then associated into chains parallel to the c axis through O-H⋯N hydrogen bonds involving the water mol-ecule of crystallization. Electron density associated with an additional solvent mol-ecule of partial occupancy and disordered about a twofold axis was removed with the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The given chemical formula and other crystal data do not take into account the unknown solvent molecule(s).

  12. Crystal structure of an unknown tetra­hydro­furan solvate of tetra­kis­(μ 3-cyanato-κ3 N:N:N)tetra­kis­[(triphenyl­phosphane-κP)­silver(I)

    Science.gov (United States)

    Frenzel, Peter; Schaarschmidt, Dieter; Jakob, Alexander; Lang, Heinrich

    2015-01-01

    In the title compound, [{[(C6H5)3P]Ag}4{NCO}4], a distorted Ag4N4-heterocubane core is set up by four AgI ions being coordinated by the N atoms of the cyanato anions in a μ 3-bridging mode. In addition, a tri­phenyl­phosphine ligand is datively bonded to each of the AgI ions. Intra­molecular Ag⋯Ag distances as short as 3.133 (9) Å suggest the presence of argentophilic (d 10⋯d 10) inter­actions. Five moderate-to-weak C—H⋯O hydrogen-bonding inter­actions are observed in the crystal structure, spanning a three-dimensional network. A region of electron density was treated with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9–18] following unsuccessful attempts to model it as being part of disordered tetra­hydro­furan solvent mol­ecules. The given chemical formula and other crystal data do not take into account these solvent mol­ecules. PMID:26594421

  13. Crystal structure of 2-[(3S,4S)-4-(anthracen-9-yl)-1-(4-meth­oxy­phen­yl)-2-oxoazetidin-3-yl]-2-aza-2H-phenalene-1,3-dione unknown solvate

    Science.gov (United States)

    Çelik, Ísmail; Akkurt, Mehmet; Jarrahpour, Aliasghar; Rad, Javad Ameri; Çelik, Ömer

    2015-01-01

    The central β-lactam ring of the title compound, C36H24N2O4, is almost planar (r.m.s. deviation = 0.003 Å) and makes dihedral angles of 17.17 (19), 89.76 (17) and 78.44 (17)° with the benzene ring, the anthracene ring (r.m.s. deviation = 0.003 Å) and the 1H-benzo[de]iso­quinoline-1,3(2H)-dione moiety, which is nearly planar [maximum deviation = 0.098 (2) Å], respectively. The mol­ecular structure is stabilized by an intra­molecular C—H⋯N hydrogen bond. In the crystal, mol­ecules are linked via C—H⋯π and π–π stacking inter­actions [centroid–centroid distances = 3.5270 (19) and 3.779 (2) Å], forming a three-dimensional structure. A region of disordered electron density, probably disordered solvent mol­ecules, was treated with the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9–18], which indicated a solvent cavity of 322 Å3 containing approximately 91 electrons. Their formula mass and unit-cell characteristics were not taken into account during the refinement. PMID:25844239

  14. Crystal structure of an unknown solvate of bis­(tetra-n-butyl­ammonium) [N,N′-(4-tri­fluoro­methyl-1,2-phenyl­ene)bis­(oxamato)-κ4 O,N,N′,O′]nickelate(II)

    Science.gov (United States)

    Eya’ane Meva, François; Schaarschmidt, Dieter; Rüffer, Tobias

    2015-01-01

    In the title compound, [N(C4H9)4]2[Ni(C11H3F3N2O6)] or [N(n-Bu)4]2[Ni(topbo)] [n-Bu = n-butyl and topbo = 4-tri­fluoro­methyl-1,2-phenyl­enebis(oxamate)], the Ni2+ cation is coordinated by two deprotonated amido N atoms and two carboxyl­ate O atoms, setting up a slightly distorted square-planar coordination environment. The [Ni(topbo]2− anion lies on a twofold rotation axis. Due to an incompatibility with the point-group symmetry of the complete mol­ecule, orientational disorder of the CF3 group is observed. The tetra­hedral ammonium cations and the anion are linked by weak inter­molecular C—H⋯O and C—H⋯F hydrogen-bonding inter­actions into a three-dimensional network. A region of electron density was treated with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9–18] following unsuccessful attempts to model it as plausible solvent mol­ecule(s). The given chemical formula and other crystal data do not take into account the unknown solvent mol­ecule. PMID:26090126

  15. (4,4′-Dimethoxy-2,2′-bipyridine-κ2N,N′bis[2-(pyridin-2-ylphenyl-κC1]iridium(III hexafluoridophosphate unknown solvate

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    Yano Natsumi

    2016-03-01

    Full Text Available The asymmetric unit of the title complex, [Ir(C11H8N2(C12H12N2O2]PF6, comprises a [Ir(ppy2(diMeO-bpy]+ cation (Hppy = 2-phenylpyridine and diMeO-bpy = 4,4′-dimethoxy-2,2′-bipyridine and a PF6− anion. The IrIII atom is coordinated by two anionic ppy− ligands, each coordinating in a C^N cyclometalated mode, and one neutral diMeO-bpy ligand, leading to a distorted octahedral geometry defined by a cis-C2N4 donor set. Intermolecular C—F...H contacts lead to a three-dimensional architecture that define columns parallel to a. Unknown disordered solvent molecules reside in these columns with the electron density being treated with SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18]. The unit-cell data do not reflect the presence of the unresolved solvent.

  16. CREDO: a protein-ligand interaction database for drug discovery.

    Science.gov (United States)

    Schreyer, Adrian; Blundell, Tom

    2009-02-01

    Harnessing data from the growing number of protein-ligand complexes in the Protein Data Bank is an important task in drug discovery. In order to benefit from the abundance of three-dimensional structures, structural data must be integrated with sequence as well as chemical data and the protein-small molecule interactions characterized structurally at the inter-atomic level. In this study, we present CREDO, a new publicly available database of protein-ligand interactions, which represents contacts as structural interaction fingerprints, implements novel features and is completely scriptable through its application programming interface. Features of CREDO include implementation of molecular shape descriptors with ultrafast shape recognition, fragmentation of ligands in the Protein Data Bank, sequence-to-structure mapping and the identification of approved drugs. Selected analyses of these key features are presented to highlight a range of potential applications of CREDO. The CREDO dataset has been released into the public domain together with the application programming interface under a Creative Commons license at http://www-cryst.bioc.cam.ac.uk/credo. We believe that the free availability and numerous features of CREDO database will be useful not only for commercial but also for academia-driven drug discovery programmes.

  17. An orthorhombic polymorph of N1,N4-diphenyl-3,6-bis(phenyliminocyclohexa-1,4-diene-1,4-diamine

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    Keiji Ohno

    2014-04-01

    Full Text Available A new orthorhombic polymorph of the title compound, C30H24N4, with a density of 1.315 Mg m−3, has been obtained. The molecule is centrosymmetric with the centroid of the cyclohexa-1,4-diene ring located on an inversion center. The two unique benzene rings are almost perpendicular to each other [dihedral angle = 86.70 (6°] and are oriented at dihedral angles of 30.79 (5 and 68.07 (5° with respect to the central cyclohexadiene ring. In the crystal, π–π stacking is observed between the central cyclohexa-1,4-diene-1,4-diamine unit and a phenyl ring of a neighboring molecule [centroid–centroid distance = 3.7043 (7 Å]. The crystal structure of the triclinic polymorph [Ohno et al. (2014. Acta Cryst. E70, o303–o304] showed chains running along the b-axis direction through weak C—H...π interactions.

  18. catena-Poly[[diaquabis(4-formylbenzoato-κO1nickel(II]-μ-pyrazine-κ2N:N′

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    Fatih Çelik

    2014-02-01

    Full Text Available In the title polymeric compound, [Ni(C8H5O32(C4H4N2(H2O2]n, the NiII atom is located on a twofold rotation axis and has a slightly distorted octahedral coordination sphere. In the equatorial plane, it is coordinated by two carboxylate O atoms of two symmetry-related monodentate formylbenzoate anions and by two N atoms of the bridging pyrazine ligand, which is bisected by the twofold rotation axis. The axial positions are occupied by two O atoms of the coordinating water molecules. In the formylbenzoate anion, the carboxylate group is twisted away from the attached benzene ring by 7.0 (6°, while the benzene and pyrazine rings are oriented at a dihedral angle of 66.2 (3°. The pyrazine ligands bridge the NiII cations, forming polymeric chains running along the b-axis direction. Intramolecular O—H...O hydrogen bonds link the water ligands to the carboxylate O atoms. In the crystal, water–water O—H...O hydrogen bonds link adjacent chains into layers parallel to the bc plane. Pyrazine–formyl C—H...O hydrogen bonds link the layers, forming a three-dimensional network. There are also weak C—H...π interactions present. The title compound is isotypic with the copper(II complex [Çelik et al. (2014a. Acta Cryst. E70, m4–m5].

  19. A P212121 polymorph of (+-clusianone

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    Teng-Jin Khoo

    2013-12-01

    Full Text Available The title compound, C33H42O4 [systematic name: (1S,5S,7R-3-benzoyl-4-hydroxy-8,8-dimethyl-1,5,7-tris(3-methylbut-2-enylbicyclo[3.3.1]nona-3-ene-2,9-dione], has a central bicyclo[3.3.1]nonane-2,4,9-trione surrounded by tetraprenylated and benzoyl groups. The compound was recrystallized several times in methanol using both a slow evaporation method and with a crystal-seeding technique. This subsequently produced diffraction-quality crystals which crystallize in the orthorhombic space group P212121, in contrast to a previous report of a structure determination in the Pna21 space group [McCandlish et al. (1976. Acta Cryst. B32, 1793–1801]. The title compound has a melting point of 365–366 K, and a specific rotation [α]20 value of +51.94°. A strong intramolecular O—H...O hydrogen bond is noted. In the crystal, molecules are assembled in the ab plane by weak C—H...O interactions.

  20. Growth and morphology of a 4PtO 6 crystals

    Science.gov (United States)

    Ohsato, H.; Sugimura, T.; Kageyama, K.

    1981-01-01

    Single crystals of Ca 4PtO 6 were precipitated from molten CaCl 2 in a wet atmosphere at 800-1000°C. Above 900°C, CaO single crystals coexisted. The Ca 4PtO 6 crystals obtained were transparent with pale brown or pale yellow colour, and were mostly granular, about 1 mm in size. The crystal habit was a combination of the {112¯0}, {101¯0}, {101¯2}, {011¯1} and {202¯1} cryst al faces. Some prismatic crystals were found, 2 mm long and 0.1 mm wide. They were found to be twinned with the (10-0) plane. The crystal has a trigonal unit cell with a = 9.332 Å, c = 11.26 Å; and with six formula units of which the space group is R—c. It is uniaxial positive with refractive indices 1.85 hydrochloric acid. The growth mechanism of Ca 4PtO 6 crystals was also discussed.

  1. FROM WATER BY NANOFILTRATION

    Directory of Open Access Journals (Sweden)

    A. Torabian, G.R.Nabi Bihdendi, P. Zanganeh Ranjbar, N. Razmkhah

    2007-07-01

    Full Text Available Nanofiltration, widely developed over the past decade, is a promising technology for the treatment of organic and inorganic pollutants in surface and groundwater resources. The aim of the present research was to study the efficiency of textile dyes removal by a commercial nanofilter NF90 (Dow-Film Tec. Dye rejection was studied using basic dye (Basic Chrysoidine Cryst Yellow Gold 0.4% with its relevant additive. Experiments were continued until the fouling time of the membrane. Each experiment was repeated after washing to evaluate the efficiency of the washing process. Results showed that the values of color removal were 97.98 % for the simulated textile wastewater containing basic dye. The membrane was sensitive to fouling since most of dyes were used for polyamide textile dyeing. Washing the membrane with a solution including NaOH (pH=12 and HCl (pH=2 showed its efficiency to solve the fouling problem. The filtration process was efficient and promising for reusing wastewater in this industry.

  2. Low-level laser therapy: Case-control study in dogs with sterile pyogranulomatous pododermatitis

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    Roberta Perego

    2016-08-01

    Full Text Available Aim: Low-level laser therapy (LLLT is a therapeutic photobiostimulation with properties in reducing swelling, inflammation, and promoting tissue healing. The objective of this pilot study was to evaluate LLLT in sterile pyogranulomatous pododermatitis in five dogs. Materials and Methods: In each dog, one lesion was designated as the control (treated with a 0.0584% hydrocortisone aceponate spray, and one or more other lesions were treated with a gallium aluminum arsenide-laser, daily for 5 days. Lesions were scored before treatment (D0, at the end (D4, 16 days after the last laser treatment (D20, and after 2 months (D65. Results: Comparing the treated lesion group with the control lesion group, the clinical score was similar at D0, whereas there was a statistically significant difference at D4 and D20; in the treated group over time, there was a statistically significant improvement between D0, D4, and D20. Lesion recurrence was absent in more than 50% of the treated lesions at D65. No adverse reactions were reported. Conclusion: Given the positive results of this first clinical study, it would be interesting to extend the study to confirm the validity of this type of therapy in sterile pyogranulomatous pododermatitis in the dog.

  3. 番茄设施栽培专用新品种晋番茄6号的选育%Breeding of New Tomato F1 Hybrid for Greenhouses Jinfanqie 6

    Institute of Scientific and Technical Information of China (English)

    王永珍; 张剑国

    2011-01-01

    Jinfanqie 6 is a new tomato hybrid with parental lines of D65-62 and N98-3. Its plant is indeterminate with high resistance to ToMV , medium resistance to CMV and complex resistance to some main diseases. Its ripe fruits are oblate, red and less deformed of good quality, long shelf life, fitting for transportation as well as good market ability. Single fruit ranges 180 to 250 gram. Its yield is more than 90 000 kg/hm2. It could be cultivated in greenhouses.%晋番茄6号是用自交系D65-62作母本、N98-3作父本配制的一代杂种,属无限生长类型,中熟,高抗番茄花叶病毒,中抗黄瓜花叶病毒,复合抗病性强.其果实高扁,成熟果大红色,耐贮运,单果质量180~250 g,不易产生畸裂果,商品性好,一般产量在90 000 kg/hm2以上.适于温室大棚栽培.

  4. Bacterial spore inactivation at 45-65 °C using high pressure processing: study of Alicyclobacillus acidoterrestris in orange juice.

    Science.gov (United States)

    Silva, Filipa V M; Tan, Eng Keat; Farid, Mohammed

    2012-10-01

    High pressure processing (HPP) is a new non-thermal technology commercially used to pasteurize fruit juices and extend shelf-life, while preserving delicate aromas/flavours and bioactive constituents. Given the spoilage incidents and economic losses due to Alicyclobacillus acidoterrestris in the fruit juice industry, the use of high pressure (200 MPa - 600 MPa) in combination with mild temperature (45 °C-65 °C) for 1-15 min, to inactivate these spores in orange juice were investigated. As expected, the higher the temperature, pressure and time, the larger was the A. acidoterrestris inactivation. The survival curves were described by the first order Bigelow model. For 200 MPa, D(45 °C) = 43.9 min, D(55 °C) = 28.8 min, D(65 °C) = 5.0 min and z-value = 21.3 °C. At 600 MPa, D(45 °C) = 12.9 min, D(55 °C) = 7.0 min, D(65 °C) = 3.4 min and z-value = 34.4 °C. Spores were inactivated at 45 °C and 600 MPa, and at 65 °C only 200 MPa was needed to achieve reduction in spore numbers. Results demonstrated that HPP allowed A. acidoterrestris spore inactivation at lower temperatures (45-65 °C) than conventional thermal processing (85-95 °C) without pressure, yielding a fresher and higher quality preserved food.

  5. PTT纤维长毛绒产品数字化测配色方法探讨%PTT Fiber Plush Products Digital Color Matching Technology

    Institute of Scientific and Technical Information of China (English)

    朱正锋; 王军华; 杨德丽

    2008-01-01

    应用datacolor SF600分光光度计及datamatch3.5测色配色软件,采用条件等色的计算机配色方式,以CIE标准施照态D65和CIE标准观察者为基础,探讨了用于长毛绒产品的PTT纤维数字化测配色工艺路线与技术方法,分析了在可见光范围内PTT纤维染色过程中反射率R%、K/S值的变化规律.以R、Y、B色料三原素为基础建立了用于PTT纤维配色数据库,得到能在CIE标准施照态D65和CIE标准观察者2个条件下染得与产品标样相同色泽的染色处方,其方法可对纤维类产品的染色测色配色提供借鉴.

  6. 三种分子生物学诊断技术对结核病诊断价值的比较%A study of the value of three molecular diagnostic techniques in the diagnosis of tuberculosis

    Institute of Scientific and Technical Information of China (English)

    黄芳; 党丽云; 孙惠平; 杨翰; 邬霞

    2015-01-01

    reference,Xpert MTB/RIF showed the highest sensitivity of 87.6% (163/186),the minimum rate of missed diagnosis of 12.4% (24/193),and the highest negative predictive value of 88.5% (185/209);SAT-TB showed the highest specificity of 98.2% (214/218),the minimum rate of misdiagnosis of 1.8% (4/218),the highest positive predictive value of 97.2% (138/142).With the result of TB 960 rapid liquid culture as the reference,the sensitivity and the specificity of Xpert MTB/RIF were 95.52%(128/134) and 95.24% (20/21).The accordance rate of Xpert MTB/RIF and TB 960 rapid liquid culture was 95.48% (148/155).Conclusion The 3 molecular detection methods showed good results for the auxiliary diagnosis of tuberculosis.Xpert MTB/RIF had the best performance both in smear positive and negative specimens and it can detect rifampicin related rpoB gene mutations at the same time.%目的 评估实时荧光RNA恒温扩增检测(SAT)、分枝杆菌核酸检测(TB-NTM-PCR)及多色巢式荧光定量PCR(Xpert MTB/RIF)法对结核病诊断的价值.方法 收集2014年4-7月西安市结核病胸部肿瘤医院收治的确诊为肺结核患者的痰标本共378份,同时采用痰直接抗酸染色镜检、SAT、TB-NTM-PCR及MTB 960快速液体培养和Xpert MTB/RIF法对标本进行检测.以MTB 960快速液体培养及痰直接抗酸染色镜检结果为金标准,分析SAT法、TB-NTM-PCR法及Xpert MTB/RIF法对MTB的检出率.采用x2检验比较3种分子生物学检测方法的阳性率.结果 SAT、TB-NTM-PCR及Xpert MTB/RIF法检测的总体阳性率分别为37.6%(142/378)、37.8% (143/378)和53.4%(202/378);涂阳培阳时,SAT、TB-NTM-PCR及Xpert MTB/RIF法检测的阳性率分别为84.6% (77/91)、91.2% (83/91)和96.7%(88/91),3种检测方法的阳性率比较差异有统计学意义(P =0.018 2);涂阴培阳时,SAT、TB-NTM-PCR及Xpert MTB/RIF法检测的阳性率分别为61.9% (60/97)、44.3%(43/97)和80.4%(78/97),3种检测方法的阳性率比

  7. Doping silver nanoparticles in AOT lyotropic lamellarphases

    Institute of Scientific and Technical Information of China (English)

    CHEN; Xiao

    2001-01-01

    aerosol OT/water/oil system, J. Colloid Interface Sci., 1979, 70: 577-583.[15]Fontell, K., The structure of the lamellar liquid crystalline phase in serosol OT-water system, J. Colloid Interface Sci.,1973, 44: 318-329.[16]Kotlarchyk, M., Sheu, E. Y., Capel, M., Structural and dynamical transformations between neighboring dense microemulsion phases, Phys. Rev. A, 1992, 46: 928-939.[17]Antelmi, D. A., Kekicheff, P., Measurement of the compressibility modulus in a lyotropic lamellar phase stabilized by undulation forces, J. Phys. Chem. B, 1997, 101: 8169-8179.[18]Wang, W., Efrima, S., Regev, O., Directing silver nanoparticles into colloid-surfactant lyotropic lamellar systems, J. Phys.Chem. B, 1999, 103: 5613-5621.[19]Chidichimo, G., La Mesa, C., Ranieri, G. A. et al., NMR investigation of the lamellar mesophase occuring in the system aerosol OT-water, Mol. Cryst. Liq. Cryst., 1987, 150b: 221-236.[20]Callaghan, P. T., Soderman, O., Examination of the lamellar phase of aerosol OT/water using pulsed field gradient nuclear magnetic resonance, J. Phys. Chem., 1983, 87: 1737-744.

  8. Study of ion implanted Al0.25Ga0.75As/GaAs by Raman spectroscopy

    Institute of Scientific and Technical Information of China (English)

    LIU; Pijun

    2001-01-01

    [1]Ramam, A., Chua, S. J., Luminescence anomaly in band gap tailored In0.35(GaxAl1-x)0.47As quaternary alloy growth by molecular beam epitaxy, J. Cryst. Growth, 1997, 175: 1294.[2]Xu, X. G., Huang, B. B., Ren, H. W. et al., Study on the stability of GaAs/AlGaAs superlattice structure, Acta Physica Sinica (Overseas Edition), 1995, 4: 47.[3]Yoon, S. F., Miao, Y. B., Radhakrishnan, K., Some characteristic of silicon-doped In0.52Al0.48As grown lattice-matched on InP substrates by molecular beam epitaxy, Thin. Solid Films, 1996, 287: 284.[4]Nakamura, K., Fuyuki, T., Matsunami, H., Strain in GaP films heteroepitaxially grown in Si by Metalorganic Chemical Vapor Deposition, Jan. J. Appl. Phys., 1998, 37: 4231.[5]Sadao Adachi, GaAs, AlAs, and AlxGa1-xAs: Material parameters for use in research and device applications, J. Appl. Phys., 1985, 58: R1.[6]Attolini, G., Francesio, L., Franzosi, P. et al., Raman scattering study of residual strain in GaAs/InP heterostructures, J. Appl. Phys., 1994, 75: 4156.[7]Helmy, A. S., Bryce, A. C., Ironside, C. N. et al., Raman spectroscopy for characterizing compositional intermixing in GaAs/AlGaAs heterostructures, Appl. Phys. Lett., 1999, 74: 3978.[8]Jencic, I., Bench, M. W., Robertson, I. M. et al., A comparison of the amorphization induced in AlxGa1-xAs and GaAs by heavy-ion irradiation, J. Appl. Phys., 1991, 69: 1287.[9]Wickboldt, P., Anastassakis, E., Sauer, R. et al., Raman phonon piezospectroscopy in GaAs: Infrared measurements, Phys. Rev. B, 1987, 35: 1362.[10]Leng, J., Qian, Y., Chen, P. et al., Disorder activated optical modes and the phonon dispersion of AlxGa1-xAs lattice vibration, Solid State Commun., 1989, 69: 311.[11]Wagner, A., Koidl, P., Newman, P. G., Resonance effects in Raman scattering by dopant-induced local vibrational modes in III-V semiconductors, Appl. Phys. Lett., 1991, 59: 1729.[12]Masayuki Sugiura, Masato Kishi, Takashi Katoda, In situ observation of the strain

  9. Determining the melting curves of NiSi using the laser-heated diamond anvil cell and the multi-anvil press

    Science.gov (United States)

    Wann, E.; Lord, O. T.; Dobson, D. P.; Hunt, S. A.; Wood, I. G.; Vocadlo, L.; Ahmed, J.; Walker, A. M.; Santangeli, J. R.; Walter, M. J.

    2012-12-01

    . Physics of the Earth and Planetary Interiors 1994, 85, 319. (3) Gessmann, C. K.; Wood, B. J.; Rubie, D. C.; Kilburn, M. R. Earth and Planetary Science Letters 2001, 184, 367. (4) Lord, O. T.; Voccadlo, L.; Wood, I. G.; Dobson, D. P.; Clark, S. M.; Walter, M. J. J. Appl. Cryst. 2012, 45, 726 (5) Vočadlo, L.; Wood, I. G.; Dobson, D. J Appl Cryst. 2012, 45, 186. (6) Lord, O. T., Walter, M. J., Dobson, D. P., Armstrong, L., Clark, S. M., Kleppe, A. J. Geophys. Res., 2010, 115, B06208.

  10. Dielectric and Optical Properties of CdS-Polymer Nanocomposites Prepared by the Successive Ionic Layer Adsorption and Reaction (SILAR) Method

    Science.gov (United States)

    Azizian-Kalandaragh, Yashar; Aydemir, Umut; Altindal, Şemsettin

    2014-04-01

    The successive ionic layer adsorption and reaction (SILAR) method has been used to grow epitaxial CdS-polymer nanostructures as thin films with different surface morphology and particle size. The main purpose of the study was to investigate the dielectric properties and a.c. electrical conductivity ( σ a.c.), by a.c. impedance spectroscopy between 1 kHz and 1 MHz, at room temperature, of CdS-polymer nanocomposites produced by use of 2, 6, and 10 cycles of SILAR. The surface morphology and optical absorption of the samples were characterized by scanning electron microscopy (SEM) and UV-visible spectroscopy, respectively. Determination of the energy gaps of CdS-polymer nanocomposites prepared by use of different numbers of cycles of SILAR reveals that the band gap decreases with increasing number of cycles (J. Cryst. Growth 305, 175-180, 2007). This behavior is because of the growth of nanoparticles in the matrix materials, and can be explained by changes in the amount of confinement as a consequence of particle size variation. SEM images also confirm that different numbers of cycles lead to different morphology. Frequency-dependent dielectric properties and a.c. electrical conductivity of the samples prepared by use of different numbers of cycles of SILAR were investigated, and comparative studies on some electrophysical properties of the samples are reported. Experimental results show that values of the dielectric constant ( ɛ'), dielectric loss ( ɛ″), dielectric loss tangent (tan δ), the real ( M') and imaginary ( M″) parts of electric modulus, and σ a.c. are highly dependent on the frequency and the number of cycles. It can be concluded that changing the frequency and the number of cycles substantially alters both the dielectric properties and a.c. electrical conductivity of the samples.

  11. Three phenanthroline–metal complexes with topologically similar but geometrically different conformations

    Directory of Open Access Journals (Sweden)

    Miguel Angel Harvey

    2016-11-01

    Full Text Available The structures of three related complexes of general formula M(pds(nab2 [pds is the peroxodisulfate anion and nab is an nitrogen-containing aromatic base], viz. bis(2,9-dimethyl-1,10-phenanthroline-κ2N,N′(peroxodisulfato-κ2O,O′cadmium, [Cd(S2O8(C14H12N22], (V, bis(3,4,7,8-tetramethy-1,10-phenanthroline-κ2N,N′(peroxodisulfato-κ2O,O′zinc, [Zn(S2O8(C16H16N22], (VI, and bis(3,4,7,8-tetramethy-1,10-phenanthroline-κ2N,N′(peroxodisulfato-κ2O,O′cadmium, [Cd(S2O8(C16H16N22], (VII, present the same topological coordination, with three chelating ligands in an MN4O2 polyhedron. The main difference resides in the fact that the first two complexes are bisected by a crystallographic twofold axis, thus providing a symmetrical environment to the cation, while in the third one this symmetry is disrupted into a clearly unsymmetrical disposition, probably by way of an unusually strong intramolecular C—H...O hydrogen bond. The situation is compared with similar interactions in the literature. The structure of (V is based on a redetermination in the correct space group C2/c of the structure originally described in the Cc space group [Harvey et al. (2001. Aust. J. Chem. 54, 307–311; Marsh (2004. Acta Cryst. B60, 252–253].

  12. Sulfur Solubility In Silicate Melts: A Thermochemical Model

    Science.gov (United States)

    Moretti, R.; Ottonello, G.

    A termochemical model for calculating sulfur solubility of simple and complex silicate melts has been developed in the framework of the Toop-Samis polymeric approach combined with a Flood - Grjotheim theoretical treatment of silicate slags [1,2]. The model allows one to compute sulfide and sulfate content of silicate melts whenever fugacity of gaseous sulphur is provided. "Electrically equivalent ion fractions" are needed to weigh the contribution of the various disproportion reactions of the type: MOmelt + 1/2S2 ,gas MSmelt+1/2O2 ,gas (1) MOmelt + 1/2S2 ,gas + 3/2O2 ,gas MSO4 ,melt (2) Eqs. 1 and 2 account for the oxide-sulfide and the oxide-sulfate disproportiona- tion in silicate melt. Electrically equivalent ion fractions are computed, in a fused salt Temkin notation, over the appropriate matrixes (anionic and cationic). The extension of such matrixes is calculated in the framework of a polymeric model previously developed [1,2,3] and based on a parameterization of acid-base properties of melts. No adjustable parameters are used and model activities follow the raoultian behavior implicit in the ion matrix solution of the Temkin notation. The model is based on a huge amount of data available in literature and displays a high heuristic capability with virtually no compositional limits, as long as the structural role assigned to each oxide holds. REFERENCES: [1] Ottonello G., Moretti R., Marini L. and Vetuschi Zuccolini M. (2001), Chem. Geol., 174, 157-179. [2] Moretti R. (2002) PhD Thesis, University of Pisa. [3] Ottonello G. (2001) J. Non-Cryst. Solids, 282, 72-85.

  13. Crystal structures of 2-(4-nitrophenyl-3-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-one and 2-(2-nitrophenyl-3-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-one

    Directory of Open Access Journals (Sweden)

    Hemant Yennawar

    2015-04-01

    Full Text Available The crystal structures are reported of the isomeric compounds 2-(4-nitrophenyl-3-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-one, (I, and 2-(2-nitrophenyl-3-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-one, (II, both C20H14N2O3S, being the para-nitro and ortho-nitro forms, respectively, the meta-form of which is known [Yennawar et al. (2013. Acta Cryst. E69, o1679]. The six-membered thiazone ring fused with a benzene ring displays a screw-boat conformation with a total puckering amplitude of 0.627 (1 Å in (I, and a near screw-boat conformation with a total puckering amplitude of 0.600 (1 Å in (II. The dihedral angles between the planes of the substituent nitrophenyl and phenyl and rings with the benzene ring of the parent benzothiazone moiety are 75.93 (5 and 82.61 (5° [in (I], and 76.79 (6 and 71.66 (6° [in (II]. Weak intermolecular C—H...O hydrogen-bonding interactions between aromatic H-atom donors and both a nitro-O atom and a thiazone O-atom acceptor in (I and a thiazone O atom in (II are present, forming in (I a centrosymmetric 22-membered cyclic dimer which is extended through a similar inversion-related 14-membered cyclic hydrogen-bonding association into a zigzag chain structure extending along c. In (II, a single intermolecular C—H...O hydrogen bond gives a chain structure extending along b. In addition, weak C—H...π interactions are present in both structures [minimum C...ring-centroid separations = 3.630 (2 and 3.581 (2 Å, respectively].

  14. Electron densities by the maximum entropy method (MEM) for various types of prior densities: a case study on three amino acids and a tripeptide.

    Science.gov (United States)

    Prathapa, Siriyara Jagannatha; Mondal, Swastik; van Smaalen, Sander

    2013-04-01

    Dynamic model densities according to Mondal et al. [(2012), Acta Cryst. A68, 568-581] are presented for independent atom models (IAM), IAMs after high-order refinements (IAM-HO), invariom (INV) models and multipole (MP) models of α-glycine, DL-serine, L-alanine and Ala-Tyr-Ala at T ≃ 20 K. Each dynamic model density is used as prior in the calculation of electron density according to the maximum entropy method (MEM). We show that at the bond-critical points (BCPs) of covalent C-C and C-N bonds the IAM-HO and INV priors produce reliable MEM density maps, including reliable values for the density and its Laplacian. The agreement between these MEM density maps and dynamic MP density maps is less good for polar C-O bonds, which is explained by the large spread of values of topological descriptors of C-O bonds in static MP densities. The density and Laplacian at BCPs of hydrogen bonds have similar values in MEM density maps obtained with all four kinds of prior densities. This feature is related to the smaller spatial variation of the densities in these regions, as expressed by small magnitudes of the Laplacians and the densities. It is concluded that the use of the IAM-HO prior instead of the IAM prior leads to improved MEM density maps. This observation shows interesting parallels to MP refinements, where the use of the IAM-HO as an initial model is the accepted procedure for solving MP parameters. A deconvolution of thermal motion and static density that is better than the deconvolution of the IAM appears to be necessary in order to arrive at the best MP models as well as at the best MEM densities.

  15. Crystal structure of di-μ-chlorido-bis[chloridobis(1,2-dimethyl-5-nitro-1H-imidazole-κN3copper(II] acetonitrile disolvate

    Directory of Open Access Journals (Sweden)

    Patrick J. Quinlivan

    2016-11-01

    Full Text Available 1,2-Dimethyl-5-nitroimidazole (dimetridazole, dimet is a compound that belongs to a class of nitroimidazole drugs that are effective at inhibiting the activity of certain parasites and bacteria. However, there are few reports that describe structures of compounds that feature metals complexed by dimet. Therefore, we report here that dimet reacts with CuCl2·H2O to yield a chloride-bridged copper(II dimer, [Cu2Cl4(C5H7N3O24] or [Cu(μ-ClCl(dimet2]2. In this molecule, the CuII ions are coordinated in an approximately trigonal–bipyramidal manner, and the molecule lies across an inversion center. The dihedral angle between the imidazole rings in the asymmetric unit is 4.28 (7°. Compared to metronidazole, dimetridazole lacks the hydroxyethyl group, and thus cannot form intermolecular O...H hydrogen-bonding interactions. Instead, [Cu(μ-ClCl(dimet2]2 exhibits weak intermolecular interactions between the hydrogen atoms of C—H groups and (i oxygen in the nitro groups, and (ii the terminal and bridging chloride ligands. The unit cell contains four disordered acetonitrile molecules. These were modeled as providing a diffuse contribution to the overall scattering by SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18], which identified two voids, each with a volume of 163 Å3 and a count of 46 electrons, indicative of a total of four acetonitrile molecules. These acetonitrile molecules are included in the chemical formula to give the expected calculated density and F(000.

  16. Structure of iron saturated C-lobe of bovine lactoferrin at pH 6.8 indicates a weakening of iron coordination.

    Science.gov (United States)

    Rastogi, Nilisha; Singh, Avinash; Singh, Prashant K; Tyagi, Tapesh K; Pandey, Sada; Shin, Kouichirou; Kaur, Punit; Sharma, Sujata; Singh, Tej P

    2016-05-01

    The bilobal lactoferrin is an approximately 76 kDa glycoprotein. It sequesters two Fe(3+) ions together with two CO(3)(2-) ions. The C-terminal half (residues, Tyr342-Arg689, C-lobe) of bovine lactoferrin (BLF) (residues Ala1-Arg689) was prepared by limited proteolysis using trypsin. Both C-lobe and intact BLF were saturated to 100%. Both of them retained up to nearly 85% of iron at pH 6.5. At pH 5.0, C-lobe retained 75% of iron whereas intact protein could retain only slightly more than 60%. At pH 4.0 both contained 25% iron and at pH 2.0 they were left with iron concentration of only 10%. The structure of iron saturated C-lobe was determined at 2.79 Å resolution and refined to R(cryst) and R(free) factors of 0.205 and 0.273, respectively. The structure contains two crystallographically independent molecules, A and B. They were found to have identical structures with an r.m.s. shift of 0.5 Å for their C(α) atoms. A high solvent content of 66% was observed in the crystals. The average value of an overall B-factor was 68.0 Å(2). The distance of 2.9 Å observed for the coordination bond between Fe(3+) ion and N(e2) of His595 appeared to be considerably longer than the normally observed values of 1.9-2.2 Å. This indicated that the coordination bond involving His595 may be absent. Other coordination distances were observed in the range of 2.1-2.3 Å. Based on the present structure of iron saturated C-lobe, it may be stated that His595 is the first residue to dissociate from ferric ion when the pH is lowered.

  17. Crystal structure of tetra-kis-[μ2-2-(di-methyl-amino)-ethano-lato-κ(3) N,O:O]di-μ3-hydroxido-di-thio-cyanato-κ(2) N-dichromium(III)dilead(II) di-thio-cyanate aceto-nitrile monosolvate.

    Science.gov (United States)

    Rusanova, Julia A; Semenaka, Valentyna V; Omelchenko, Irina V

    2016-04-01

    The tetra-nuclear complex cation of the title compound, [Cr2Pb2(NCS)2(OH)2(C4H10NO)4](SCN)2·CH3CN, lies on an inversion centre. The main structural feature of the cation is a distorted seco-norcubane Pb2Cr2O6 cage with a central four-membered Cr2O2 ring. The Cr(III) ion is coordinated in a distorted octa-hedron, which involves two N atoms of one bidentate ligand and one thio-cyanate anion, two μ2-O atoms of 2-(di-methyl-amino)-ethano-late ligands and two μ3-O atoms of hydroxide ions. The coordination geometry of the Pb(II) ion is a distorted disphenoid, which involves one N atom, two μ2-O atoms and one μ3-O atom. In addition, weak Pb⋯S inter-actions involving the coordinating and non-coordinating thio-cyanate anions are observed. In the crystal, the complex cations are linked through the thio-cyanate anions via the Pb⋯S inter-actions and O-H⋯N hydrogen bonds into chains along the c axis. The chains are further linked together via S⋯S contacts. The contribution of the disordered solvent aceto-nitrile mol-ecule was removed with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9-18] procedure in PLATON. The solvent is included in the reported mol-ecular formula, weight and density.

  18. On the theoretical determination of the Prigogine-Defay ratio in glass transition

    Science.gov (United States)

    Tropin, Timur V.; Schmelzer, Jürn W. P.; Gutzow, Ivan; Schick, Christoph

    2012-03-01

    In a recent analysis [J. W. P. Schmelzer and I. Gutzow, J. Chem. Phys. 125, 184511 (2006), 10.1063/1.2374894] it was shown for the first time that - in contrast to earlier belief arising from the works of Prigogine and Defay [Chemical Thermodynamics (Longman, London, 1954), Chap. 19; The first French edition of this book was published in 1950] and Davies and Jones [Adv. Phys. 2, 370 (1953), 10.1080/00018735300101252; Davies and Jones Proc. R. Soc. London, Ser. A 217, 26 (1953), 10.1098/rspa.1953.0044] - a satisfactory theoretical interpretation of the experimentally observed values of the so-called Prigogine-Defay ratio Π, being a combination of jumps of thermodynamic coefficients at glass transition, can be given employing only one structural order parameter. According to this analysis, this ratio has to be, in full agreement with experimental findings, larger than one (Π > 1). Its particular value depends both on the thermodynamic properties of the system under consideration and on cooling and heating rates. Based on above-mentioned analysis, latter dependence on cooling rates has been studied in detail in another own preceding paper [T. V. Tropin, J. W. P. Schmelzer, and C. Schick, J. Non-Cryst. Solids 357, 1303 (2011), 10.1016/j.jnoncrysol.2010.12.005]. In the present analysis, an alternative general method of determination of the Prigogine-Defay ratio is outlined, allowing one to determine this ratio having at ones disposal the generalized equation of state of the glass-forming melts under consideration and, in particular, the knowledge of the equilibrium properties of the melts in the glass transformation range. Employing, as an illustration of the method, a particular model for the description of glass-forming melts, theoretical estimates are given for this ratio being, again, in good agreement with experimental data.

  19. Effect of Different pH Hydrogen Peroxide Bleaching on Human Dentin Color and Transparency%不同pH值过氧化氢漂白影响人牙本质颜色及透明度的对比及机制初探

    Institute of Scientific and Technical Information of China (English)

    王苏豫; 李冬霞

    2015-01-01

    目的:探讨不同pH值过氧化氢溶液对牙本质颜色和透明度的影响.方法:将30颗刚拔除的人前磨牙随机分为两组,每组15例,沿牙长轴剖开、去髓,使用pH=4.5和pH=7.0的两种过氧化氢溶液分别进行漂白,用Crystaleye电脑比色仪观察牙本质颜色和透明度的变化,以及与时间的关系,初步分析其机制.结果:pH=7.0过氧化氢溶液漂白1周后牙本质颜色变黄,透明度下降,基质金属蛋白酶活性下降.pH=4.5过氧化氢溶液漂白1周后牙本质颜色变黄,透明度下降,3周后部分牙本质颜色恢复,同时基质金属蛋白酶活性升高,两组差异有统计学意义(P<0.05).结论::pH=7.0的过氧化氢溶液氧化性较强,对牙本质的破坏较大,pH=4.5过氧化氢溶液对牙本质破坏性略低.其机制与牙源性基质金属蛋白酶活性有关.

  20. Crystal structure of the anti-(carcinoembryonic antigen) single-chain Fv antibody MFE-23 and a model for antigen binding based on intermolecular contacts.

    Science.gov (United States)

    Boehm, M K; Corper, A L; Wan, T; Sohi, M K; Sutton, B J; Thornton, J D; Keep, P A; Chester, K A; Begent, R H; Perkins, S J

    2000-03-01

    MFE-23 is the first single-chain Fv antibody molecule to be used in patients and is used to target colorectal cancer through its high affinity for carcinoembryonic antigen (CEA), a cell-surface member of the immunoglobulin superfamily. MFE-23 contains an N-terminal variable heavy-chain domain joined by a (Gly(4)Ser)(3) linker to a variable light-chain (V(L)) domain (kappa chain) with an 11-residue C-terminal Myc-tag. Its crystal structure was determined at 2.4 A resolution by molecular replacement with an R(cryst) of 19.0%. Five of the six antigen-binding loops, L1, L2, L3, H1 and H2, conformed to known canonical structures. The sixth loop, H3, displayed a unique structure, with a beta-hairpin loop and a bifurcated apex characterized by a buried Thr residue. In the crystal lattice, two MFE-23 molecules were associated back-to-back in a manner not seen before. The antigen-binding site displayed a large acidic region located mainly within the H2 loop and a large hydrophobic region within the H3 loop. Even though this structure is unliganded within the crystal, there is an unusually large region of contact between the H1, H2 and H3 loops and the beta-sheet of the V(L) domain of an adjacent molecule (strands DEBA) as a result of intermolecular packing. These interactions exhibited remarkably high surface and electrostatic complementarity. Of seven MFE-23 residues predicted to make contact with antigen, five participated in these lattice contacts, and this model for antigen binding is consistent with previously reported site-specific mutagenesis of MFE-23 and its effect on CEA binding.

  1. Crystal structures of three 4-substituted-2,2′-bipyridines synthesized by Sonogashira and Suzuki–Miyaura cross-coupling reactions

    Directory of Open Access Journals (Sweden)

    Thuy Luong Thi Thu

    2017-04-01

    Full Text Available Facile synthetic routes for three 4-substituted 2,2′-bipyridine derivatives, 4-[2-(4-methylphenylethynyl]-2,2′-bipyridine, C19H14N2, (I, 4-[2-(pyridin-3-ylethynyl]-2,2′-bipyridine, C17H11N3, (II, and 4-(indol-4-yl-2,2′-bipyridine, C18H13N3, (III, via Sonogashira and Suzuki–Miyaura cross-coupling reactions, respectively, are described. As indicated by X-ray analysis, the 2,2′-bipyridine core, the ethylene linkage and the substituents of (I and (II are almost planar [dihedral angles between the two ring systems: 8.98 (5 and 9.90 (6° for the two molecules of (I in the asymmetric unit and 2.66 (14° for (II], allowing π-conjugation. On the contrary, in (III, the indole substituent ring is rotated significantly out of the bipyridine plane [dihedral angle = 55.82 (3°], due to steric hindrance. The crystal packings of (I and (II are dominated by π–π interactions, resulting in layers of molecules parallel to (30-2 in (I and columns of molecules along the a axis in (II. The packing of (III exhibits zigzag chains of molecules along the c axis interacting through N—H...N hydrogen bonds and π–π interactions. The contributions of unknown disordered solvent molecules to the diffraction intensities in (II were removed with the SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] algorithm of PLATON. The given chemical formula and other crystal data do not take into account these solvent molecules.

  2. Redetermined structure of gossypol (P3 polymorph

    Directory of Open Access Journals (Sweden)

    Muhabbat Honkeldieva

    2015-07-01

    Full Text Available An improved crystal structure of the title compound, C30H30O8 (systematic name: 1,1′,6,6′,7,7′-hexahydroxy-5,5′-diisopropyl-3,3′-dimethyl[2,2′-binaphthalene]-8,8′-dicarbaldehyde, was determined based on modern CCD data. Compared to the previous structure [Talipov et al. (1985. Khim. Prirod. Soedin. (Chem. Nat. Prod., 6, 20–24], geometrical precision has been improved (typical C—C bond-distance s.u. = 0.002 Å in the present structure compared to 0.005 Å in the previous structure and the locations of several H atoms have been corrected. The gossypol molecules are in the aldehyde tautomeric form and the dihedral angle between the naphthyl fragments is 80.42 (4°. Four intramolecular O—H...O hydrogen bonds are formed. In the crystal, inversion dimers with graph-set motif R22(20 are formed by pairs of O—H...O hydrogen bonds; another pair of O—H...O hydrogen bonds with the same graph-set motif links the dimers into [001] chains. The packing of such chains in the crystal leads to the formation of channels (diameter = 5–8 Å propagating in the [101] direction. The channels presumably contain highly disordered solvent molecules; their contribution to the scattering was removed with the SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] routine in PLATON and the stated molecular mass, density etc., do not take them into account.

  3. μ-XRF analysis of glasses: a non-destructive utility for Cultural Heritage applications.

    Science.gov (United States)

    Vaggelli, G; Cossio, R

    2012-02-07

    This paper presents a μ-XRF analytical approach for a non-destructive study of Cultural Heritage glass finds. This technique can be used for quantitative analysis of small volumes of solid samples, with a sensitivity that is superior to the electron microprobe but inferior to an ICP-MS system. An experimental set-up with natural and synthetic glass standards is proposed here for the quantitative analyses of major and trace elements on glass objects which cannot be sampled such as small archaeological or historical artefacts from Cultural Heritage. The described method, performed by means of the commercial μ-XRF Eagle III-XPL, was applied to Islamic glass specimens of Sasanian production (III-VII century A.D.) previously analyzed by ICP-MS and SEM-EDS techniques (P. Mirti, M. Pace, M. Negro Ponzi and M. Aceto, Archaeometry, 2008, 50(3), 429-450; P. Mirti, M. Pace, M. Malandrino and M. Negro Ponzi, J. Archaeol. Sci., 36, 1061-1069; and M. Gulmini, M. Pace, G. Ivaldi, M. Negro Ponzi and P. Mirti, J. Non-Cryst. Solids, 2009, 355, 1613-1621) and coming from the archaeological site of Veh Ardasir in modern Iraq. Major elements (Na, Mg, Al, Si, K, Ca, Fe) of glass specimens show an accuracy better than 5%. Trace elements (Cr, Mn, Sr and Zr) display an accuracy better than 5% when the checked elements have a concentration >100 ppm by weight, whereas it is around 10% with a concentration <100 ppm by weight. μ-XRF is, therefore, a suitable elemental analysis technique for the non-destructive study of small glass finds due to its relatively good accuracy, reproducibility and low detection limits (∼tens ppm).

  4. The influence of the stereochemistry of alanine residue on the solid state conformation and crystal packing of opioid peptides containing D-Ala or L-Ala in message domain--XRD and NMR study.

    Science.gov (United States)

    Trzeciak-Karlikowska, Katarzyna; Bujacz, Anna; Ciesielski, Włodzimierz; Bujacz, Grzegorz D; Potrzebowski, Marek J

    2011-08-18

    In this work, an X-ray diffraction (XRD) and solid state NMR study of two tetrapeptides with different stereochemistry of alanine residue is presented using Tyr-(D-Ala)-Phe-Gly (1), an N-terminal sequence of opioid peptide dermorphin, and its biologically inactive analog Tyr-(L-Ala)-Phe-Gly (2). Single-crystal XRD proved that 1 crystallized under different conditions from exclusively one structure: a monoclinic crystal with P2(1) space group. In contrast, 2 very easily formed at least three crystallographic modifications, 2a (monoclinic P2(1)), 2b (orthorhombic P2(1)2(1)2) and 2c (tetragonal P4(1)2(1)2). Solid-state NMR spectroscopy was employed to investigate the structure and molecular dynamics of 1, 2a, and 2b. By employing different NMR experiments (dipolar dephasing and PILGRIM) and an analysis of the (13)C principal elements of the chemical shift tensor (CST), it was proven that the main skeleton of tetrapeptides is rigid, whereas significant differences in the molecular motion of the aromatic residues were observed. Comparing current data with those of previous studies (J. Phys. Chem. B2004, 108, 4535-4545 and Cryst. Growth Des. 2009, 9, 4050-4059), it can be assumed that an important preorganization mechanism anticipating the formation of peptide crystals containing D-Ala in sequence is the intramolecular CH-π interaction, which occurs for the amino acid with D stereochemistry. This effect may be responsible for the formation of only one crystallographic form of D-Ala peptides.

  5. Patterson-function direct methods for structure determination of organic compounds from powder diffraction data. XVI.

    Science.gov (United States)

    Rius, Jordi

    2011-01-01

    A new type of direct methods (DM) called Patterson-function DM are presented that directly explore the Patterson instead of the modulus function. Since they work with the experimental intensities, they are particularly well suited for handling powder diffraction data. These methods are based on the maximization of the sum function S(P) ∝ ∑H(I(H)-)G(-H)(Φ) in terms of the Φ phases of the structure factors. The quantity accessible from the experiment is I(H), the equidistributed multiplet intensity of reflection H, and is the average intensity taken over all non-systematically absent reflections. G(-H)(Φ) is the calculated structure-factor amplitude of the squared structure that includes the positivity and the atomicity of the density function in its definition. The S(P) sum function can be optimized with the Patterson-function tangent formula (TF) using a variant of the S-FFT algorithm [Rius et al. (2007), Acta Cryst. A63, 131-134]. It is important that overlapped reflections also participate in the phase refinement, so that not only the resolved reflections but the whole pattern contribute decisively to the refinement. The increase in effective data resolution minimizes Fourier series termination effects and improves the accuracy of G(Φ). The Patterson-function TF has been applied to synchrotron powder data of various organic compounds. In all cases the molecules were easily identified in the respective Fourier maps. By way of illustration the method is applied to synchrotron powder data of a dimer formed by 30 symmetry-independent non-H atoms. Since single-crystal data may be regarded as overlap-free powder data, it is clear that Patterson-function DM can cope with powder and single-crystal data.

  6. Crystal structures of deuterated sodium molybdate dihydrate and sodium tungstate dihydrate from time-of-flight neutron powder diffraction.

    Science.gov (United States)

    Fortes, A Dominic

    2015-07-01

    Time-of-flight neutron powder diffraction data have been measured from ∼90 mol% deuterated isotopologues of Na2MoO4·2H2O and Na2WO4·2H2O at 295 K to a resolution of sin (θ)/λ = 0.77 Å(-1). The use of neutrons has allowed refinement of structural parameters with a precision that varies by a factor of two from the heaviest to the lightest atoms; this contrasts with the X-ray based refinements where precision may be > 20× poorer for O atoms in the presence of atoms such as Mo and W. The accuracy and precision of inter-atomic distances and angles are in excellent agreement with recent X-ray single-crystal structure refinements whilst also completing our view of the hydrogen-bond geometry to the same degree of statistical certainty. The two structures are isotypic, space-group Pbca, with all atoms occupying general positions, being comprised of edge- and corner-sharing NaO5 and NaO6 polyhedra that form layers parallel with (010) inter-leaved with planes of XO4 (X = Mo, W) tetra-hedra that are linked by chains of water mol-ecules along [100] and [001]. The complete structure is identical with the previously described molybdate [Capitelli et al. (2006 ▸). Asian J. Chem. 18, 2856-2860] but shows that the purported three-centred inter-action involving one of the water mol-ecules in the tungstate [Farrugia (2007 ▸). Acta Cryst. E63, i142] is in fact an ordinary two-centred 'linear' hydrogen bond.

  7. Three phenanthroline-metal complexes with topologically similar but geometrically different conformations.

    Science.gov (United States)

    Harvey, Miguel Angel; Suarez, Sebastián; Baggio, Ricardo

    2016-11-01

    The structures of three related complexes of general formula M(pds)(nab)2 [pds is the peroxodi-sulfate anion and nab is an nitro-gen-containing aromatic base], viz. bis(2,9-dimethyl-1,10-phenanthroline-κ(2)N,N')(peroxodi-sulfato-κ(2)O,O')cadmium, [Cd(S2O8)(C14H12N2)2], (V), bis-(3,4,7,8-tetra-methy-1,10-phenanthroline-κ(2)N,N')(peroxodi-sulfato-κ(2)O,O')zinc, [Zn(S2O8)(C16H16N2)2], (VI), and bis-(3,4,7,8-tetra-methy-1,10-phenanthroline-κ(2)N,N')(peroxodi-sulfato-κ(2)O,O')cadmium, [Cd(S2O8)(C16H16N2)2], (VII), present the same topological coordination, with three chelating ligands in an MN4O2 polyhedron. The main difference resides in the fact that the first two complexes are bis-ected by a crystallographic twofold axis, thus providing a symmetrical environment to the cation, while in the third one this symmetry is disrupted into a clearly unsymmetrical disposition, probably by way of an unusually strong intra-molecular C-H⋯O hydrogen bond. The situation is compared with similar inter-actions in the literature. The structure of (V) is based on a redetermination in the correct space group C2/c of the structure originally described in the Cc space group [Harvey et al. (2001). Aust. J. Chem.54, 307-311; Marsh (2004 ▸). Acta Cryst. B60, 252-253].

  8. Modified Statistical Dynamical Diffraction Theory: A Novel Metrological Analysis Method for Partially Relaxed and Defective Carbon-doped Silicon and Silicon Germanium Heterostructures

    Science.gov (United States)

    Shreeman, Paul K.

    The statistical dynamical diffraction theory, which has been initially developed by late Kato remained in obscurity for many years due to intense and difficult mathematical treatment that proved to be quite challenging to implement and apply. With assistance of many authors in past (including Bushuev, Pavlov, Pungeov, and among the others), it became possible to implement this unique x-ray diffraction theory that combines the kinematical (ideally imperfect) and dynamical (the characteristically perfect diffraction) into a single system of equations controlled by two factors determined by long range order and correlation function within the structure. The first stage is completed by the publication (Shreeman and Matyi, J. Appl. Cryst., 43, 550 (2010)) demonstrating the functionality of this theory with new modifications hence called modified statistical dynamical diffraction theory (mSDDT). The foundation of the theory is also incorporated into this dissertation, and the next stage of testing the model against several ion-implanted SiGe materials has been published: (Shreeman and Matyi, physica status solidi (a)208(11), 2533-2538, 2011). The dissertation with all the previous results summarized, dives into comprehensive analysis of HRXRD analyses complete with several different types of reflections (symmetrical, asymmetrical and skewed geometry). The dynamical results (with almost no defects) are compared with well-known commercial software. The defective materials, to which commercially available modeling software falls short, is then characterized and discussed in depth. The results will exemplify the power of the novel approach in the modified statistical dynamical diffraction theory: Ability to detect and measure defective structures qualitatively and quantitatively. The analysis will be compared alongside with TEM data analysis for verification and confirmation. The application of this theory will accelerate the ability to quickly characterize the relaxed

  9. Distinguishing tautomerism in the crystal structure of (Z)-N-(5-ethyl-2,3-di-hydro-1,3,4-thiadiazol-2-ylidene) -4-methylbenzenesulfonamide using DFT-D calculations and {sup 13}C solid-state NMR

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaozhou; Bond, Andrew D.; Johansson, Kristoffer E.; Van de Streek, Jacco, E-mail: jacco.vandestreek@sund.ku.dk [Department of Pharmacy, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100 (Denmark)

    2014-08-01

    The crystal structure of (Z)-N-(5-ethyl-2,3-di-hydro-1,3,4-thiadiazol-2-ylidene) -4-methylbenzenesulfonamide contains an imine tautomer, rather than the previously reported amine tautomer. The tautomers can be distinguished using dispersion-corrected density functional theory calculations and by comparison of calculated and measured {sup 13}C solid-state NMR spectra. The crystal structure of the title compound, C{sub 11}H{sub 13}N{sub 3}O{sub 2}S{sub 2}, has been determined previously on the basis of refinement against laboratory powder X-ray diffraction (PXRD) data, supported by comparison of measured and calculated {sup 13}C solid-state NMR spectra [Hangan et al. (2010 ▶). Acta Cryst. B66, 615–621]. The mol@@ecule is tautomeric, and was reported as an amine tautomer [systematic name: N-(5-ethyl-1,3,4-thia@@diazol-2-yl)-p-toluene@@sulfonamide], rather than the correct imine tautomer. The protonation site on the mol@@ecule’s 1,3,4-thia@@diazole ring is indicated by the inter@@molecular contacts in the crystal structure: N—H⋯O hydrogen bonds are established at the correct site, while the alternative protonation site does not establish any notable inter molecular inter@@actions. The two tautomers provide essentially identical Rietveld fits to laboratory PXRD data, and therefore they cannot be directly distinguished in this way. However, the correct tautomer can be distinguished from the incorrect one by previously reported qu@@anti@@tative criteria based on the extent of structural distortion on optimization of the crystal structure using dispersion-corrected density functional theory (DFT-D) calculations. Calculation of the {sup 13}C SS-NMR spectrum based on the correct imine tautomer also provides considerably better agreement with the measured {sup 13}C SS-NMR spectrum.

  10. The application of eigensymmetries of face forms to X-ray diffraction intensities of crystals twinned by 'reticular merohedry'.

    Science.gov (United States)

    Klapper, H; Hahn, Th

    2012-01-01

    This paper is an extension of a previous treatment of `twins by merohedry' with full lattice coincidence [Σ = 1, Klapper & Hahn (2010). Acta Cryst. A66, 327-346] to `twins by reticular merohedry' with partial lattice coincidence (Σ > 1). Again, the sets of symmetrically equivalent reflections {hkl} are considered as sets of equivalent faces (face forms) {hkl}, and the behaviour of the oriented eigensymmetries of these forms under the action of a twin operation is used to determine the X-ray reflection sets, the intensities of which are affected or not affected by the twinning. The following cases are treated: rhombohedral obverse/reverse Σ3 twins, cubic Σ3 (spinel) twins, tetragonal Σ5 twins (twin elements m'(120), 2'[ ̅210]) and hexagonal Σ7 twins (m'(12 ̅30), 2'[2 ̅10]). For each case the twin laws for all relevant point groups are defined, and the twin diffraction cases A (intensity of twin-related reflection sets not affected), B1 (intensity affected), B2 (intensity affected only by anomalous scattering) and S (single, i.e. non-coincident reflection sets) are derived for all twin laws. A special treatment is provided for the cubic Σ3 twins, where the cubic face forms first have to be split into up to four rhombohedral subforms with a threefold axis along one of the four cube directions, here [111]. These subforms exhibit different twin diffraction cases analogous to those derived for the rhombohedral obverse/reverse Σ3 twins. A complete list of the split forms and their diffraction cases for all cubic point groups and all Σ3 twin elements is given. The application to crystal structure determination of crystals twinned by reticular merohedry and to X-ray topographic mapping of twin domains is discussed.

  11. Effect of the Ga Content on the Magnetic Properties for the Dual -phase Nanocrystalline Bonded Magnets%微量Ga元素对双相纳米晶磁体性能的影响

    Institute of Scientific and Technical Information of China (English)

    朱明刚; 董生智; 李岫梅; 李卫

    2001-01-01

    探讨了微量的Ga替代Fe对Nd2Fe14B/Fe3B+(少量)α-Fe永磁材料的晶体结构及磁性能的影响。结果表明:添加微量的Ga同样可减小晶粒尺寸;在Ga含量x<1%(原子百分比)的范围,随着x的增加,Br和(BH)max随晶化时间变化的曲线由非线性向线性转化;矫顽力jHc下降到一个最小值后,又缓慢上升;当x=0.2时,综合磁性能较好。%Effect of the Ga content substituting the Fe on the cryst alstructure and magnetic properties for the Nd2Fe14B/Fe3B+(little) α-Fe permanent magnetic materials was discussed. The results show that the crystal size was markedly decresed by adding Ga. With the increase of x, the curves of the Br and the (BH)max change wi th annealing time from non-linearity to linearity in the Ga content range of x<1at%, the coercive force jHc decreases at first to a minimum and then increaes slowly. The best value of the magnetic properties is obtained while the x=0.2.

  12. Dynamic and temperature dependent response of physical vapor deposited Se in freely standing nanometric thin films

    Science.gov (United States)

    Yoon, Heedong; McKenna, Gregory B.

    2016-05-01

    Here, we report results from an investigation of nano-scale size or confinement effects on the glass transition and viscoelastic properties of physical vapor deposited selenium films. The viscoelastic response of freely standing Se films was determined using a biaxial membrane inflation or bubble inflation method [P. A. O'Connell and G. B. McKenna, Science 307, 1760-1763 (2005)] on films having thicknesses from 60 to 267 nm and over temperatures ranging from Tg, macroscopic - 15 °C to Tg, macroscopic + 21 °C. Time-temperature superposition and time-thickness superposition were found to hold for the films in the segmental dispersion. The responses are compared with macroscopic creep and recoverable creep compliance data for selenium [K. M. Bernatz et al., J. Non-Cryst. Solids 307, 790-801 (2002)]. The time-temperature shift factors for the thin films show weaker temperature dependence than seen in the macroscopic behavior, being near to Arrhenius-like in their temperature dependence. Furthermore, the Se films exhibit a "rubbery-like" stiffening that increases as film thickness decreases similar to prior observations [P. A. O'Connell et al., Macromolecules 45(5), 2453-2459 (2012)] for organic polymers. In spite of the differences from the macroscopic behavior in the temperature dependence of the viscoelastic response, virtually no change in Tg as determined from the thickness dependence of the retardation time defining Tg was observed in the bubble inflation creep experiments to thicknesses as small as 60 nm. We also find that the observed rubbery stiffening is consistent with the postulate of K. L. Ngai et al. [J. Polym. Sci., Part B: Polym. Phys. 51(3), 214-224 (2013)] that it should correlate with the change of the macroscopic segmental relaxation.

  13. A new equilibrium form of zircon crystal

    Institute of Scientific and Technical Information of China (English)

    WANG; Xiang

    2001-01-01

    [1]Hartman, P., Perdok, G., On the relationship between structure and morphology of crystals, Acta Cryst., 1955, 8: 525-529.[2]Woensdregt, C. F., Computation of surface of energies in an electrostatic point charge model, Ⅱ. Application to zircon (ZrSiO4), Phys. Chem. Minerals, 1992, 19: 417-423.[3]Kern, R., The equilibrium form of a crystal, in Morphology of Crystal (ed. Sunnagawa, I.), Tokyo: Terra Scientific Publishing Company, 1970, 77-206.[4]Machenzie, J. K., Moore, J. W., Nickolas, J. F., Bond broken at atomically flat crystal surface, I. Face-centered and body-centered cubic crystal, J. Phys. Chem. Solids, 1962, 23: 185-196.[5]?. Machenzie, J. K., Nicholas, J. F., Bond broken at atomically flat crystal surface, ?. Crystals containing many atoms in a primitive unit cell, J. Phys. Chem. Solids, 1962, 23: 197-205.[6]Hazen, R. M., Finger, L. W., Crystal structure and compressibility of zircon at high pressure, Am. Mineral, 1979, 64:196-201.[7]Pupin, J. P., Zircon and granite petrology, Contrib. Mineral Petrol., 1980, 73: 207-220.[8]Wang, X., Kienast, J. R., Morphology and geochemistry of zircon: a case study on zircon from the microgranitoid enclaves,Science in China, Series D, 1999, 42(5): 544-552.[9]Wang, X., Li, W. X., Discovery of the { 211 }-type of zircon and its petrogenetic implication, Chinese Sci. Bull., 2001 (inpress).[10]Wang, X., Quantitative description of zircon morphology and its dynamics analysis, Science in China, Series D, 1998,41(4): 422-428.

  14. Heteropoly acids of the Keggin type with N-substituted

    Institute of Scientific and Technical Information of China (English)

    FU; Xiangkai

    2001-01-01

    [1]Hartman, P., Perdok, G., On the relationship between structure and morphology of crystals, Acta Cryst., 1955, 8: 525-529.[2]Woensdregt, C. F., Computation of surface of energies in an electrostatic point charge model, Ⅱ. Application to zircon (ZrSiO4), Phys. Chem. Minerals, 1992, 19: 417-423.[3]Kern, R., The equilibrium form of a crystal, in Morphology of Crystal (ed. Sunnagawa, I.), Tokyo: Terra Scientific Publishing Company, 1970, 77-206.[4]Machenzie, J. K., Moore, J. W., Nickolas, J. F., Bond broken at atomically flat crystal surface, I. Face-centered and body-centered cubic crystal, J. Phys. Chem. Solids, 1962, 23: 185-196.[5]?. Machenzie, J. K., Nicholas, J. F., Bond broken at atomically flat crystal surface, ?. Crystals containing many atoms in a primitive unit cell, J. Phys. Chem. Solids, 1962, 23: 197-205.[6]Hazen, R. M., Finger, L. W., Crystal structure and compressibility of zircon at high pressure, Am. Mineral, 1979, 64:196-201.[7]Pupin, J. P., Zircon and granite petrology, Contrib. Mineral Petrol., 1980, 73: 207-220.[8]Wang, X., Kienast, J. R., Morphology and geochemistry of zircon: a case study on zircon from the microgranitoid enclaves,Science in China, Series D, 1999, 42(5): 544-552.[9]Wang, X., Li, W. X., Discovery of the { 211 }-type of zircon and its petrogenetic implication, Chinese Sci. Bull., 2001 (inpress).[10]Wang, X., Quantitative description of zircon morphology and its dynamics analysis, Science in China, Series D, 1998,41(4): 422-428.

  15. Preparation of some new coumarin dyes

    Institute of Scientific and Technical Information of China (English)

    LUO; Xianjin

    2001-01-01

    [1]Hartman, P., Perdok, G., On the relationship between structure and morphology of crystals, Acta Cryst., 1955, 8: 525-529.[2]Woensdregt, C. F., Computation of surface of energies in an electrostatic point charge model, Ⅱ. Application to zircon (ZrSiO4), Phys. Chem. Minerals, 1992, 19: 417-423.[3]Kern, R., The equilibrium form of a crystal, in Morphology of Crystal (ed. Sunnagawa, I.), Tokyo: Terra Scientific Publishing Company, 1970, 77-206.[4]Machenzie, J. K., Moore, J. W., Nickolas, J. F., Bond broken at atomically flat crystal surface, I. Face-centered and body-centered cubic crystal, J. Phys. Chem. Solids, 1962, 23: 185-196.[5]?. Machenzie, J. K., Nicholas, J. F., Bond broken at atomically flat crystal surface, ?. Crystals containing many atoms in a primitive unit cell, J. Phys. Chem. Solids, 1962, 23: 197-205.[6]Hazen, R. M., Finger, L. W., Crystal structure and compressibility of zircon at high pressure, Am. Mineral, 1979, 64:196-201.[7]Pupin, J. P., Zircon and granite petrology, Contrib. Mineral Petrol., 1980, 73: 207-220.[8]Wang, X., Kienast, J. R., Morphology and geochemistry of zircon: a case study on zircon from the microgranitoid enclaves,Science in China, Series D, 1999, 42(5): 544-552.[9]Wang, X., Li, W. X., Discovery of the { 211 }-type of zircon and its petrogenetic implication, Chinese Sci. Bull., 2001 (inpress).[10]Wang, X., Quantitative description of zircon morphology and its dynamics analysis, Science in China, Series D, 1998,41(4): 422-428.

  16. Crystal structure of an unknown solvate of (piperazine-κN{5,10,15,20-tetrakis[4-(benzoyloxyphenyl]porphyrinato-κ4N}zinc

    Directory of Open Access Journals (Sweden)

    Soumaya Nasri

    2016-07-01

    Full Text Available The title compound, [Zn(C72H44N4O8(C4H10N2] or [Zn(TPBP(pipz] (where TPBP and pipz are 5,10,15,20-tetrakis[4-(benzoyloxyphenyl]porphyrinato and piperazine ligands respectively, features a distorted square-pyramidal coordination geometry about the central ZnII atom. This central atom is chelated by the four N atoms of the porphyrinate anion and further coordinated by a nitrogen atom of the piperazine axial ligand, which adopts a chair confirmation. The average Zn—N(pyrrole bond length is 2.078 (7 Å and the Zn— N(pipz bond length is 2.1274 (19 Å. The zinc cation is displaced by 0.4365 (4 Å from the N4C20 mean plane of the porphyrinate anion toward the piperazine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling deformations. In the crystal, the supramolecular structure is made by parallel pairs of layers along (100, with an interlayer distance of 4.100 Å while the distance between two pairs of layers is 4.047 Å. A region of electron density was treated with the SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] procedure in PLATON following unsuccessful attempts to model it as being part of disordered n-hexane solvent and water molecules. The given chemical formula and other crystal data do not take into account these solvent molecules.

  17. Crystal structure of an unknown solvate of (piperazine-κN){5,10,15,20-tetra­kis­[4-(benzo­yloxy)phen­yl]porphyrinato-κ4 N}zinc

    Science.gov (United States)

    Nasri, Soumaya; Ezzayani, Khaireddine; Turowska-Tyrk, Ilona; Roisnel, Thierry; Nasri, Habib

    2016-01-01

    The title compound, [Zn(C72H44N4O8)(C4H10N2)] or [Zn(TPBP)(pipz] (where TPBP and pipz are 5,10,15,20-tetra­kis­[4-(benzo­yloxy)phen­yl]porphyrinato and piperazine ligands respectively), features a distorted square-pyramidal coordin­ation geometry about the central ZnII atom. This central atom is chelated by the four N atoms of the porphyrinate anion and further coordinated by a nitro­gen atom of the piperazine axial ligand, which adopts a chair confirmation. The average Zn—N(pyrrole) bond length is 2.078 (7) Å and the Zn— N(pipz) bond length is 2.1274 (19) Å. The zinc cation is displaced by 0.4365 (4) Å from the N4C20 mean plane of the porphyrinate anion toward the piperazine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling deformations. In the crystal, the supra­molecular structure is made by parallel pairs of layers along (100), with an inter­layer distance of 4.100 Å while the distance between two pairs of layers is 4.047 Å. A region of electron density was treated with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9–18] procedure in PLATON following unsuccessful attempts to model it as being part of disordered n-hexane solvent and water mol­ecules. The given chemical formula and other crystal data do not take into account these solvent mol­ecules. PMID:27555935

  18. Crystal structure of an unknown solvate of (piperazine-κN){5,10,15,20-tetra-kis-[4-(benzo-yloxy)phen-yl]porphyrinato-κ(4) N}zinc.

    Science.gov (United States)

    Nasri, Soumaya; Ezzayani, Khaireddine; Turowska-Tyrk, Ilona; Roisnel, Thierry; Nasri, Habib

    2016-07-01

    The title compound, [Zn(C72H44N4O8)(C4H10N2)] or [Zn(TPBP)(pipz] (where TPBP and pipz are 5,10,15,20-tetra-kis-[4-(benzo-yloxy)phen-yl]porphyrinato and piperazine ligands respectively), features a distorted square-pyramidal coordin-ation geometry about the central Zn(II) atom. This central atom is chelated by the four N atoms of the porphyrinate anion and further coordinated by a nitro-gen atom of the piperazine axial ligand, which adopts a chair confirmation. The average Zn-N(pyrrole) bond length is 2.078 (7) Å and the Zn- N(pipz) bond length is 2.1274 (19) Å. The zinc cation is displaced by 0.4365 (4) Å from the N4C20 mean plane of the porphyrinate anion toward the piperazine axial ligand. This porphyrinate macrocycle exhibits major saddle and moderate ruffling deformations. In the crystal, the supra-molecular structure is made by parallel pairs of layers along (100), with an inter-layer distance of 4.100 Å while the distance between two pairs of layers is 4.047 Å. A region of electron density was treated with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9-18] procedure in PLATON following unsuccessful attempts to model it as being part of disordered n-hexane solvent and water mol-ecules. The given chemical formula and other crystal data do not take into account these solvent mol-ecules.

  19. Crystal structure of tetra­kis­[μ2-2-(di­methyl­amino)­ethano­lato-κ3 N,O:O]di-μ3-hydroxido-di­thio­cyanato-κ2 N-dichromium(III)dilead(II) di­thio­cyanate aceto­nitrile monosolvate

    Science.gov (United States)

    Rusanova, Julia A.; Semenaka, Valentyna V.; Omelchenko, Irina V.

    2016-01-01

    The tetra­nuclear complex cation of the title compound, [Cr2Pb2(NCS)2(OH)2(C4H10NO)4](SCN)2·CH3CN, lies on an inversion centre. The main structural feature of the cation is a distorted seco-norcubane Pb2Cr2O6 cage with a central four-membered Cr2O2 ring. The CrIII ion is coordinated in a distorted octa­hedron, which involves two N atoms of one bidentate ligand and one thio­cyanate anion, two μ2-O atoms of 2-(di­methyl­amino)­ethano­late ligands and two μ3-O atoms of hydroxide ions. The coordination geometry of the PbII ion is a distorted disphenoid, which involves one N atom, two μ2-O atoms and one μ3-O atom. In addition, weak Pb⋯S inter­actions involving the coordinating and non-coordinating thio­cyanate anions are observed. In the crystal, the complex cations are linked through the thio­cyanate anions via the Pb⋯S inter­actions and O—H⋯N hydrogen bonds into chains along the c axis. The chains are further linked together via S⋯S contacts. The contribution of the disordered solvent aceto­nitrile mol­ecule was removed with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9–18] procedure in PLATON. The solvent is included in the reported mol­ecular formula, weight and density. PMID:27375871

  20. Large angle elastic and inelastic scattering of 14.93 keV photons

    Energy Technology Data Exchange (ETDEWEB)

    Singh, P.; Mehta, D.; Kumar, S.; Sharma, M.; Puri, S.; Shahi, J.S.; Singh, N. E-mail: nsingh@pu.ac.in

    2004-07-01

    Elastic and inelastic scattering cross-sections for the 14.93 keV photons (Y-K{alpha} X-rays) were measured at an angle of 141 deg. in the elements with 6 {<=} Z {<=} 92 and 1 {<=} Z {<=} 50, respectively. A reflection mode geometrical arrangement involving a Y-foil excited by the 59.54 keV {gamma}-rays from the {sup 241}Am radioisotope as photon source and an HPGe/Si(Li) detector was used. The measurements were performed under vacuum {approx}10{sup -2} Torr. Special care was taken in determination of the incident photon intensity and geometrical factors and to check effects due to occurrence of Bragg diffraction from the target lattice. The measured elastic scattering cross-sections have been compared with predictions from the form-factor formalism and relativistic second-order S-matrix calculations. The modified form-factor (MF) cross-sections are higher up to 50% than the measured ones in the case of elements with the electron binding energy (BE) in vicinity of the incident photon energy and are lower up to 20% for the other elements. These deviations are smoothed by incorporating the Anomalous Scattering Factors (ASFs) to the MF values [Acta Cryst. A 46 (1990) 170]. The S-matrix values exhibit general agreement with the measured cross-sections. The measured inelastic scattering cross-sections are found to be in good agreement with those calculated using the Klein-Nishina cross-section incorporating the Hartree-Fock incoherent scattering function (ISF)

  1. Steady needle growth with 3-D anisotropic surface tension

    Institute of Scientific and Technical Information of China (English)

    Xiao-jun CHEN; Yong-qiang CHEN; Jian-pu XU; Jian-jun XU

    2008-01-01

    The effect of the anisotropic interracial en-ergy on dendritic growth has been an important sub-ject, and has preoccupied many researchers in the field of materials science and condensed matter physics. The present paper is dedicated to the study of the effect of full 3-D anisotropic Surface tension on the steady state solution of dendritic growth. We obtain the analytical form of the first order approximation solution in the reg-ular asymptotic expansion around the Ivantsov's nee-dle growth solution, which extends the steady needle growth solution of the system with isotropic surface ten-sion obtained by Xu and Yu (J. J. Xu and D. S. Yu, J. Cryst. Growth, 1998, 187: 314; J. J. Xu, Interfa-cial Wave Theory of Pattern Formation: Selection of Dendrite Growth and Viscous Fingering in a Hele-Shaw Flow, Berlin: Springer-Verlag, 1997).The solution is expanded in the general Laguerre se-ries in any finite region around the needle-tip, and it is also expanded in a power series in the far field behind the tip. Both solutions are then numerically matched in the intermediate region. Based on this global valid solution, the dependence of Peclet number Pe and the interface's morphology on the anisotropy parameter of surface ten-sion as well as other physical parameters involved are determined. On the basis of this global valid solution, we explore the effect of the anisotropy parameter on the Peclet number of growth, as well as the morphology of the interface.

  2. An unexpected oxidation: NaK5Cl2(S2O6)2 revisited

    Science.gov (United States)

    Harrison, William T. A.; Plater, M. John

    2017-01-01

    The title compound, NaK5Cl2(S2O6)2 [systematic name: sodium penta­potassium dichloride bis­(di­thio­nate)], arose as an unexpected product from an organic synthesis that used di­thio­nite (S2O4 2−) ions as a reducing agent to destroy excess permanganate ions. Compared to the previous study [Stanley (1953 ▸). Acta Cryst. 6, 187–196], the present tetra­gonal structure exhibits a root 2a × root 2a × c super-cell due to subtle changes in the orientations of the di­thio­nate anions. The structure can be visualized as a three-dimensional framework of [001] columns of alternating trans-NaO4Cl2 and KO4Cl2 octa­hedra cross-linked by the di­thio­nate ions with the inter­stices occupied by KO6Cl2 polyhedra to generate a densely packed three-dimensional framework. The asymmetric unit comprises two sodium ions (site symmetries 4 and -4, four potassium ions (site symmetries = -4, 4, 1 and 1), three chloride ions (site symmetries = 4, 4 and 2) and two half-di­thio­nate ions (all atoms on general positions). Both di­thio­nate ions are completed by crystallographic inversion symmetry. The crystal chosen for data collection was found to be rotationally twinned by 180° about the [100] axis in reciprocal space with a 0.6298 (13):0.3702 (13) domain ratio. PMID:28217339

  3. Inhibition of lactoperoxidase by its own catalytic product: crystal structure of the hypothiocyanate-inhibited bovine lactoperoxidase at 2.3-A resolution.

    Science.gov (United States)

    Singh, A K; Singh, Nagendra; Sharma, Sujata; Shin, Kouichirou; Takase, Mitsunori; Kaur, Punit; Srinivasan, A; Singh, T P

    2009-01-01

    To the best of our knowledge, this is the first report on the structure of product-inhibited mammalian peroxidase. Lactoperoxidase is a heme containing an enzyme that catalyzes the inactivation of a wide range of microorganisms. In the presence of hydrogen peroxide, it preferentially converts thiocyanate ion into a toxic hypothiocyanate ion. Samples of bovine lactoperoxidase containing thiocyanate (SCN(-)) and hypothiocyanate (OSCN(-)) ions were purified and crystallized. The structure was determined at 2.3-A resolution and refined to R(cryst) and R(free) factors of 0.184 and 0.221, respectively. The determination of structure revealed the presence of an OSCN(-) ion at the distal heme cavity. The presence of OSCN(-) ions in crystal samples was also confirmed by chemical and spectroscopic analysis. The OSCN(-) ion interacts with the heme iron, Gln-105 N(epsilon1), His-109 N(epsilon2), and a water molecule W96. The sulfur atom of the OSCN(-) ion forms a hypervalent bond with a nitrogen atom of the pyrrole ring D of the heme moiety at an S-N distance of 2.8 A. The heme group is covalently bound to the protein through two ester linkages involving carboxylic groups of Glu-258 and Asp-108 and the modified methyl groups of pyrrole rings A and C, respectively. The heme moiety is significantly distorted from planarity, whereas pyrrole rings A, B, C, and D are essentially planar. The iron atom is displaced by approximately 0.2 A from the plane of the heme group toward the proximal site. The substrate channel resembles a long tunnel whose inner walls contain predominantly aromatic residues such as Phe-113, Phe-239, Phe-254, Phe-380, Phe-381, Phe-422, and Pro-424. A phosphorylated Ser-198 was evident at the surface, in the proximity of the calcium-binding channel.

  4. Crystal structures of two 2,3-di­ethyl­naphtho­[2,3-g]quinoxaline-6,11-dione derivatives

    Science.gov (United States)

    Forsyth, Craig M.

    2017-01-01

    Two new 5,12-disubstituted 2,3-di­ethyl­naphtho­[2,3-g]quinoxaline-6,11-dione compounds were readily synthesized from the commercial dye quinizarin. For 2,3-diethyl-5,12-di­hydroxy­naphtho­[2,3-g]quinoxaline-6,11-dione, (II), C20H16N2O4, the mol­ecule displays a near planar conformation and both hy­droxy groups participate in intra­molecular O—H⋯O(carbon­yl) hydrogen bonds. In the crystal, π–π ring inter­actions [minimum ring centroid separation = 3.5493 (9) Å] form stacks of co-planar mol­ecules down the c axis, while only minor inter­molecular C—H⋯O inter­actions are present. In contrast, in 2,3-diethyl-5,12-bis­(piperidin-1-yl)naphtho­[2,3-g]quinoxaline-6,11-dione, (IV), C30H34N4O2, which contains two independent, but similar, mol­ecules in the asymmetric unit, the polycyclic cores have a significant twist, with dihedral angles of 29.79 (6) and 29.31 (7)° between the terminal rings and only minor inter­molecular C—H⋯O hydrogen-bonding inter­actions are present. Electron density associated with additional solvent mol­ecules disordered about a fourfold axis was accounted for using the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9–18]. PMID:28932420

  5. Comparison of semi-insulating InAlAs and InP:Fe for InP-based buried-heterostructure QCLs

    Science.gov (United States)

    Flores, Y. V.; Aleksandrova, A.; Elagin, M.; Kischkat, J.; Kurlov, S. S.; Monastyrskyi, G.; Hellemann, J.; Golovynskyi, S. L.; Dacenko, O. I.; Kondratenko, S. V.; Tarasov, G. G.; Semtsiv, M. P.; Masselink, W. T.

    2015-09-01

    In a previous work [Flores et al., J. Cryst. Growth 398 (2014) 40] [3] we demonstrated the advantages of using a thin InAlAs spacer layer in the fabrication of buried-heterostructure quantum-cascade lasers (QCLs), as it improves the morphology of the interface between the laser core and the InP:Fe lateral cladding. In this paper we investigate aspects of InAlAs, which are relevant for its role as insulating lateral cladding of the laser sidewalls: carrier traps, electrical resistivity, and functionality as a sole lateral cladding. We find that a thin InAlAs spacer layer not only improves the regrowth interface morphology, but also eliminates interface-related shallow electronic states, thus improving the electrical resistivity of the interface. We further find that bulk InAlAs grown by gas-source molecular-beam epitaxy as well as InP:Fe are semi-insulating at room temperature, with specific resistivities of 3 ×107 Ω cm and 2 ×108 Ω cm, respectively. Both materials have also a high thermal activation energy for electrical conductivity (0.79 eV and 0.68 eV, respectively). In order to compare the performance of InP:Fe and InAlAs as a lateral cladding, lasers were fabricated from the same QCL wafer with differing stripe insulation materials. The resulting lasers differ mainly by the lateral insulation material: SiO2, InP:Fe (with InAlAs spacer), and pure InAlAs. All devices show a similar performance and similar temperature dependence, indicating insulating properties of InAlAs adequate for application in lateral regrowth of buried-heterostructure QCLs.

  6. Can X-ray constrained Hartree-Fock wavefunctions retrieve electron correlation?

    Science.gov (United States)

    Genoni, Alessandro; Dos Santos, Leonardo H R; Meyer, Benjamin; Macchi, Piero

    2017-03-01

    The X-ray constrained wavefunction (XC-WF) method proposed by Jayatilaka [Jayatilaka & Grimwood (2001) ▸, Acta Cryst. A57, 76-86] has attracted much attention because it represents a possible third way of theoretically studying the electronic structure of atoms and molecules, combining features of the more popular wavefunction- and DFT-based approaches. In its original formulation, the XC-WF technique extracts statistically plausible wavefunctions from experimental X-ray diffraction data of molecular crystals. A weight is used to constrain the pure Hartree-Fock solution to the observed X-ray structure factors. Despite the wavefunction being a single Slater determinant, it is generally assumed that its flexibility could guarantee the capture, better than any other experimental model, of electron correlation effects, absent in the Hartree-Fock Hamiltonian but present in the structure factors measured experimentally. However, although the approach has been known for long time, careful testing of this fundamental hypothesis is still missing. Since a formal demonstration is impossible, the validation can only be done heuristically and, to accomplish this task, X-ray constrained Hartree-Fock calculations have been performed using structure factor amplitudes computed at a very high correlation level (coupled cluster) for selected molecules in isolation, in order to avoid the perturbations due to intermolecular interactions. The results show that a single-determinant XC-WF is able to capture the electron correlation effects only partially. The largest amount of electron correlation is extracted when: (i) a large external weight is used (much larger than what has normally been used in XC-WF calculations using experimental data); and (ii) the high-order reflections, which carry less information on the electron correlation, are down-weighted (or even excluded), otherwise they would bias the fitting towards the unconstrained Hartree-Fock wavefunction.

  7. Can X-ray constrained Hartree–Fock wavefunctions retrieve electron correlation?

    Directory of Open Access Journals (Sweden)

    Alessandro Genoni

    2017-03-01

    Full Text Available The X-ray constrained wavefunction (XC-WF method proposed by Jayatilaka [Jayatilaka & Grimwood (2001, Acta Cryst. A57, 76–86] has attracted much attention because it represents a possible third way of theoretically studying the electronic structure of atoms and molecules, combining features of the more popular wavefunction- and DFT-based approaches. In its original formulation, the XC-WF technique extracts statistically plausible wavefunctions from experimental X-ray diffraction data of molecular crystals. A weight is used to constrain the pure Hartree–Fock solution to the observed X-ray structure factors. Despite the wavefunction being a single Slater determinant, it is generally assumed that its flexibility could guarantee the capture, better than any other experimental model, of electron correlation effects, absent in the Hartree–Fock Hamiltonian but present in the structure factors measured experimentally. However, although the approach has been known for long time, careful testing of this fundamental hypothesis is still missing. Since a formal demonstration is impossible, the validation can only be done heuristically and, to accomplish this task, X-ray constrained Hartree–Fock calculations have been performed using structure factor amplitudes computed at a very high correlation level (coupled cluster for selected molecules in isolation, in order to avoid the perturbations due to intermolecular interactions. The results show that a single-determinant XC-WF is able to capture the electron correlation effects only partially. The largest amount of electron correlation is extracted when: (i a large external weight is used (much larger than what has normally been used in XC-WF calculations using experimental data; and (ii the high-order reflections, which carry less information on the electron correlation, are down-weighted (or even excluded, otherwise they would bias the fitting towards the unconstrained Hartree–Fock wavefunction.

  8. Can X-ray constrained Hartree–Fock wavefunctions retrieve electron correlation?

    Science.gov (United States)

    Genoni, Alessandro; Dos Santos, Leonardo H. R.; Meyer, Benjamin; Macchi, Piero

    2017-01-01

    The X-ray constrained wavefunction (XC-WF) method proposed by Jayatilaka [Jayatilaka & Grimwood (2001) ▸, Acta Cryst. A57, 76–86] has attracted much attention because it represents a possible third way of theoretically studying the electronic structure of atoms and molecules, combining features of the more popular wavefunction- and DFT-based approaches. In its original formulation, the XC-WF technique extracts statistically plausible wavefunctions from experimental X-ray diffraction data of molecular crystals. A weight is used to constrain the pure Hartree–Fock solution to the observed X-ray structure factors. Despite the wavefunction being a single Slater determinant, it is generally assumed that its flexibility could guarantee the capture, better than any other experimental model, of electron correlation effects, absent in the Hartree–Fock Hamiltonian but present in the structure factors measured experimentally. However, although the approach has been known for long time, careful testing of this fundamental hypothesis is still missing. Since a formal demonstration is impossible, the validation can only be done heuristically and, to accomplish this task, X-ray constrained Hartree–Fock calculations have been performed using structure factor amplitudes computed at a very high correlation level (coupled cluster) for selected molecules in isolation, in order to avoid the perturbations due to intermolecular interactions. The results show that a single-determinant XC-WF is able to capture the electron correlation effects only partially. The largest amount of electron correlation is extracted when: (i) a large external weight is used (much larger than what has normally been used in XC-WF calculations using experimental data); and (ii) the high-order reflections, which carry less information on the electron correlation, are down-weighted (or even excluded), otherwise they would bias the fitting towards the unconstrained Hartree–Fock wavefunction. PMID:28250952

  9. Use of colour parameters for roasted coffee assessment Utilização dos parâmetros de cor para avaliação do café torrado

    Directory of Open Access Journals (Sweden)

    Natalina Cavaco Bicho

    2012-09-01

    Full Text Available Fast and non-destructive indicators were evaluated as tools to measure the technological quality of Arabica and Robusta coffee. Accordingly, considering the roasting intensity in highly valuable commercial samples, volume, mass, apparent density, moisture, total ash, ash insoluble in hydrochloric acid, and ether extract were characterized. The chromatic parameters L*, C*, Hº were measured using illuminants D65 and C. It was found that in roasted coffee beans, the parameters L*, C*, Hº, and coordinate b* had an antagonist interaction due to an increase in the roasting intensity, whereas after milling, only L* and Hº decreased progressively. Considering that the parameters L* and Hº followed similar patterns using both illuminants, D65 and C, it can be concluded that they are appropriate to evaluate coffee colour changes during roasting, enabling a relationship with coffee quality.Avaliaram-se indicadores não destrutivos e de execução rápida, para aferir a qualidade tecnológica de cafés Arábica e Robusta. Neste contexto, considerando a intensidade da torra em amostras com elevado interesse comercial, caracterizaram-se o volume, massa, densidade aparente, umidade, cinzas totais e insolúveis em ácido clorídrico e do extrato etéreo. Foram então analisados os parâmetros cromáticos L*, C*, Hº utilizando os iluminantes D65 e C. Verificou-se que em grãos de café torrado os parâmetros L*, C*, Hº e a coordenada b* mostraram uma interação antagônica face ao acréscimo da intensidade da torra, enquanto, após a moagem, apenas o L* e o Hº decresceram progressivamente. Considerando que a coordenada L* não variou significativamente com a aplicação dos dois iluminantes, concluiu-se que este parâmetro é o mais adequado para estudar a evolução da cor durante a torra, permitindo ainda estabelecer uma correlação com a qualidade.

  10. 基于LED阵列的彩色视觉检测光源色度特性研究%Study on colorimetric properties of LED array sources for color vision application

    Institute of Scientific and Technical Information of China (English)

    祝振敏; 曲兴华; 毕超; 贾果欣; 张福民

    2012-01-01

    Color vision is based on a three-color colorimeter of colorimetric principle,and the colorimetric properties of illumination is the key factor for color imaging.Therefore based on the principle of colorimetry,in this paper we analyse and calculate the colorimetric properties of LED array sources for color vision application.By comparison with the standard D65 light source,the adjustment principle and range of correlated color temperature are studied for LED array sources.Chromaticity coordinates and relevant color temperature of white balance are also studied.The LED array source has a large range for adjusting the correlated color temperature and has a better ability of color display.Chromaticity coordinates and relevant color temperature of white balance R.G:B=254:237:90 are closer to those of the standard chromaticity.The ability of color reproduction reaches a better result of color reproduction.Therefore,the colorimetric properties of LED array sources are more appropriate for color vision application.%彩色视觉成像是基于色度学理论的三刺激值法,而光源的色度学特性是彩色成像的关键因素,因此本文以色度学理论为基础,计算并分析了用于彩色视觉检测的LED阵列光源的色度学特性,并通过于标准D65光源进行对比,研究了LED阵列光源的相关色温调节原理、范围,以及白场平衡时的色度坐标、相关色温等.LED阵列光源具有相当宽泛的相关色温调节范围,可调制出的颜色丰富,色彩的表现能力更强,色彩饱和度更高,白场平衡R:G:B=254:237:90时的色度坐标、相关色温甚至比人工D65光源更加接近于白场的标准色度,其颜色复现能力达到视觉允许的较优颜色复现效果.因此LED阵列光源的色度学特性更加适用于彩色视觉检测.

  11. Plant Growth-Promoting Rhizobacteria Inoculation to Enhance Vegetative Growth, Nitrogen Fixation and Nitrogen Remobilisation of Maize under Greenhouse Conditions.

    Directory of Open Access Journals (Sweden)

    Khing Boon Kuan

    Full Text Available Plant growth-promoting rhizobacteria (PGPR may provide a biological alternative to fix atmospheric N2 and delay N remobilisation in maize plant to increase crop yield, based on an understanding that plant-N remobilisation is directly correlated to its plant senescence. Thus, four PGPR strains were selected from a series of bacterial strains isolated from maize roots at two locations in Malaysia. The PGPR strains were screened in vitro for their biochemical plant growth-promoting (PGP abilities and plant growth promotion assays. These strains were identified as Klebsiella sp. Br1, Klebsiella pneumoniae Fr1, Bacillus pumilus S1r1 and Acinetobacter sp. S3r2 and a reference strain used was Bacillus subtilis UPMB10. All the PGPR strains were tested positive for N2 fixation, phosphate solubilisation and auxin production by in vitro tests. In a greenhouse experiment with reduced fertiliser-N input (a third of recommended fertiliser-N rate, the N2 fixation abilities of PGPR in association with maize were determined by 15N isotope dilution technique at two harvests, namely, prior to anthesis (D50 and ear harvest (D65. The results indicated that dry biomass of top, root and ear, total N content and bacterial colonisations in non-rhizosphere, rhizosphere and endosphere of maize roots were influenced by PGPR inoculation. In particular, the plants inoculated with B. pumilus S1r1 generally outperformed those with the other treatments. They produced the highest N2 fixing capacity of 30.5% (262 mg N2 fixed plant-1 and 25.5% (304 mg N2 fixed plant-1 of the total N requirement of maize top at D50 and D65, respectively. N remobilisation and plant senescence in maize were delayed by PGPR inoculation, which is an indicative of greater grain production. This is indicated by significant interactions between PGPR strains and time of harvests for parameters on N uptake and at. % 15Ne of tassel. The phenomenon is also supported by the lower N content in tassels of maize

  12. Plant Growth-Promoting Rhizobacteria Inoculation to Enhance Vegetative Growth, Nitrogen Fixation and Nitrogen Remobilisation of Maize under Greenhouse Conditions.

    Science.gov (United States)

    Kuan, Khing Boon; Othman, Radziah; Abdul Rahim, Khairuddin; Shamsuddin, Zulkifli H

    2016-01-01

    Plant growth-promoting rhizobacteria (PGPR) may provide a biological alternative to fix atmospheric N2 and delay N remobilisation in maize plant to increase crop yield, based on an understanding that plant-N remobilisation is directly correlated to its plant senescence. Thus, four PGPR strains were selected from a series of bacterial strains isolated from maize roots at two locations in Malaysia. The PGPR strains were screened in vitro for their biochemical plant growth-promoting (PGP) abilities and plant growth promotion assays. These strains were identified as Klebsiella sp. Br1, Klebsiella pneumoniae Fr1, Bacillus pumilus S1r1 and Acinetobacter sp. S3r2 and a reference strain used was Bacillus subtilis UPMB10. All the PGPR strains were tested positive for N2 fixation, phosphate solubilisation and auxin production by in vitro tests. In a greenhouse experiment with reduced fertiliser-N input (a third of recommended fertiliser-N rate), the N2 fixation abilities of PGPR in association with maize were determined by 15N isotope dilution technique at two harvests, namely, prior to anthesis (D50) and ear harvest (D65). The results indicated that dry biomass of top, root and ear, total N content and bacterial colonisations in non-rhizosphere, rhizosphere and endosphere of maize roots were influenced by PGPR inoculation. In particular, the plants inoculated with B. pumilus S1r1 generally outperformed those with the other treatments. They produced the highest N2 fixing capacity of 30.5% (262 mg N2 fixed plant-1) and 25.5% (304 mg N2 fixed plant-1) of the total N requirement of maize top at D50 and D65, respectively. N remobilisation and plant senescence in maize were delayed by PGPR inoculation, which is an indicative of greater grain production. This is indicated by significant interactions between PGPR strains and time of harvests for parameters on N uptake and at. % 15Ne of tassel. The phenomenon is also supported by the lower N content in tassels of maize treated with

  13. AcEST: DK955788 [AcEST

    Lifescience Database Archive (English)

    Full Text Available Oryza sati... 67 6e-11 sp|Q3TZZ7|ESYT2_MOUSE Extended synaptotagmin-2 OS=Mus musculus G... 66 1e-10 sp|Q9ZT4...848_DICDI Probable serine/threonine-protein kinase D... 65 3e-10 sp|A0FGR8|ESYT2_HUMAN Extended synaptotagmi...p|P41823|SY65_APLCA Synaptotagmin-1 OS=Aplysia californica GN=S... 60 7e-09 sp|Q5M7N9|ESYT3_XENTR Extended s...ynaptotagmin-3 OS=Xenopus tropic... 60 7e-09 sp|Q7ZWU7|EST2B_XENLA Extended synaptotagmin-2-B OS=Xenopus lae...v... 60 9e-09 sp|Q5FWL4|EST2A_XENLA Extended synaptotagmin-2-A OS=Xenopus laev... 60 9e-09 sp|P48231|TCB2_YE

  14. Reconstructing spectral reflectance from digital camera through samples selection

    Science.gov (United States)

    Cao, Bin; Liao, Ningfang; Yang, Wenming; Chen, Haobo

    2016-10-01

    Spectral reflectance provides the most fundamental information of objects and is recognized as the "fingerprint" of them, since reflectance is independent of illumination and viewing conditions. However, reconstructing high-dimensional spectral reflectance from relatively low-dimensional camera outputs is an illposed problem and most of methods requaired camera's spectral responsivity. We propose a method to reconstruct spectral reflectance from digital camera outputs without prior knowledge of camera's spectral responsivity. This method respectively averages reflectances of selected subset from main training samples by prescribing a limit to tolerable color difference between the training samples and the camera outputs. Different tolerable color differences of training samples were investigated with Munsell chips under D65 light source. Experimental results show that the proposed method outperforms classic PI method in terms of multiple evaluation criteria between the actual and the reconstructed reflectances. Besides, the reconstructed spectral reflectances are between 0-1, which make them have actual physical meanings and better than traditional methods.

  15. Kinetic tremor: differences between smokers and non-smokers.

    Science.gov (United States)

    Louis, Elan D

    2007-05-01

    Tremor is among the acute effects of nicotine exposure. Published studies have focused on smoking-related postural (static) hand tremor rather than kinetic tremor (tremor during hand use), and gender differences in smoking-related tremor have not been examined. In a group of adults who were sampled from a population (mean+/-S.D.=65.7+/-11.5 years, range=18-92 years), the investigator assessed whether the severity of postural and kinetic tremors differed in smokers versus non-smokers, and whether this difference was influenced by gender. Twenty-seven (9.9%) of 273 subjects were current smokers. Greater tremor was observed in smokers than non-smokers during a variety of activities (drawing a spiral, using a spoon, finger-nose-finger maneuver, all phabits should be considered carefully in order to avoid over- or underestimating the effects of occupational and non-occupational exposures to other tremor-producing neurotoxins.

  16. Physical properties and valence state of cerium in the filled skutterudite CePt₄Ge₁₂.

    Science.gov (United States)

    Gumeniuk, R; Kvashnina, K O; Schnelle, W; Nicklas, M; Borrmann, H; Rosner, H; Skourski, Y; Tsirlin, A A; Leithe-Jasper, A; Grin, Yu

    2011-11-23

    Electronic, magnetic, and transport properties of the filled platinum-germanium skutterudite CePt₄Ge₁₂ are investigated. High resolution x-ray absorption spectroscopy measurements at the cerium L(III) edge demonstrate that CePt₄Ge₁₂ in this compound has a temperature-independent valence close to three. However, magnetic susceptibility, thermopower, Hall effect, and electronic specific heat reveal a broad maximum at Tmax D 65-80 K, suggesting the presence of valence fluctuations. The Sommerfeld coefficient γ = 105 mJ mol⁻¹ K⁻², deduced from specific heat, indicates moderately enhanced band masses for CePt₄Ge₁₂. We discuss these findings and conclude that CePt₄Ge₁₂ represents a system at the border between intermediate valence (IV) and Kondo lattice behavior. In addition, the lattice specific heat and the thermal conductivity are discussed with respect to the vibrational dynamics of Ce in the [Pt₄Ge₁₂] framework.

  17. Physiological differences and their genetic backgrounds of Erigeron breviscapus populations under enhanced UV-B radiation%模拟UV-B辐射增强条件下灯盏花居群的生理差异及其遗传背景

    Institute of Scientific and Technical Information of China (English)

    冯源; 朱媛; 祖艳群; 杨生超; 陈建军; 李元

    2009-01-01

    在温室条件下,研究了模拟UV-B辐射(280~320 nm)增强对6个灯盏花居群的类黄酮、丙二醛(MDA)含量和抗氧化酶活性的影响及其种内差异,并利用ISSR分子标记技术对灯盏花居群进行遗传背景分析.结果表明:在UV-B辐射增强条件下,灯盏花D01、D53、D63和D65居群在成苗期、盛花期和成熟期的类黄酮含量均显著增加,成苗期与盛花期MDA含量显著降低:而D47和D48居群3个生育期的MDA含量和盛花期类黄酮含量均显著增加,成熟期显著降低.D01居群3个生育期的POD、APX活性,成苗期、盛花期CAT活性与盛花期SOD活性均显.著升高;D47居群3个生育期的SOD、CAT和APX活性,成熟期POD活性显著下降;1348居群3个生育期的POD、APX活性,成苗期、成熟期的SOD活性均显著下降;D53居群成苗期和盛花期SOD、APX活性,盛花期CAT活性显著增加;D63居群3个生育期的SOD、POD和APX活性均显著上升;D65居群除成熟期的CAT和APX活性没有显著变化外,3个生育期的4种抗氧化酶活性均显著上升.灯盏花居群对UV-B辐射增强的响应有明显的种内差异,D01、D53、1363和D65为UV耐性居群,而D47和D48居群的UV敏感性较高.灯盏花居群不同生育期对UV-B辐射的响应为盛花期>成苗期>成熟期.居群间的遗传多样性差异明显,在遗传距离为0.11的水平上,可将D01、D53、D63和D65居群归为一类,D47和D48居群为另一类,这与根据生理响应指数判断的UV耐性与敏感居群的结果基本一致.

  18. Euclidean color-difference formula for small-medium color differences in log-compressed OSA-UCS space.

    Science.gov (United States)

    Oleari, Claudio; Melgosa, Manuel; Huertas, Rafael

    2009-01-01

    This work continues previous research by the same authors [J. Opt. Soc. Am. A23, 2077 (2006)], where empirical small-medium color differences were represented by an ellipsoidal equation DeltaEGP in the Uniform Color System of the Optical Society of America. Now logarithmic compressions on chroma and lightness are introduced to produce a new space with Euclidean color-difference formulas DeltaEE. The CIEDE2000, DeltaEGP, and DeltaEE formulas are found statistically equivalent in the prediction of many available empirical datasets. However, DeltaEE is the simplest formula providing relationships with visual processing. These analyses hold true for CIE 1964 Supplementary Standard Observer and D65 illuminant.

  19. Comparison of CIE chromaticity values

    CSIR Research Space (South Africa)

    Van Tonder, N

    1999-02-02

    Full Text Available grey 0.4490 0.4097 Deep pink 0.5569 0.3579 Red 0.6606 0.3259 Orange 0.5881 0.3933 Bright yellow 0.5238 0.4530 Green 0.3785 0.4779 Difference green 0.3846 0.4826 Cyan 0.2929 0.3650 Deep blue 0.2906 0.2282 Table 2 The CSIR/NML x and y CIE chromaticity....4831 Green 0.2703 0.4071 Difference green 0.2776 0.4195 Cyan 0.1965 0.2261 Deep blue 0.1929 0.1082 Table 3 The CSIR/NML x and y CIE chromaticity values for illuminant D65 and 28 observer Chromaticity values xy Pale grey 0.3129 0.3304 Mid grey 0.3120 0...

  20. Linear Synchro Driving Control of CNC Powerful Spinning Machine%数控强力旋压机的直线同步进给驱动控制

    Institute of Scientific and Technical Information of China (English)

    尤娜娜; 辛世界

    2015-01-01

    For the position synchronized problem of two linear motors in the synchronous drive process of 3D65CNC powerful spin⁃ning machine, the method of variable universe fuzzy PID control was applied to compensate position error of two permanent magnet syn⁃chronous linear motors, variable universe fuzzy PID synchronous controller was designed. But the single axis should have good servo system, which was an important prerequisite for biaxial synchronized state. Based on obvious nonlinear and hard to carry on the accurate modeling for linear motor, methods of model⁃free adaptive control and pseudo⁃derivative feedback control were applied to control single⁃axis linear motor. At last, the feasibility of the scheme was verified through Simulink simulation. The simulation results show that the scheme has improved the synchronization control precision.%针对3D65CNC强力旋压机同步驱动过程中的两直线电机位置不同步的问题,采用变论域模糊PID控制方法对两永磁同步直线电机的位置误差进行补偿,设计了变论域模糊PID同步控制器。但单轴具有良好的伺服系统是双轴保持同步状态的重要前提,针对直线电机具有明显的非线性、不易对其进行精确的建模,采用无模型自适应控制和伪微分反馈( PDF)控制的方法对单轴直线电机进行控制。最后通过Simulink仿真证明该方案提高了同步控制的精度。

  1. Influences of different fight sources of standard illuminants on colorimetric parameters of normal tongue tip color%不同标准照明体光源对正常舌尖舌色色度学参数的影响

    Institute of Scientific and Technical Information of China (English)

    曾常春; 杨利; 许颖; 刘培培; 郭世珺; 刘颂豪

    2012-01-01

    Objective To compare the influences of light sources A, B, C E and D65 of standard illuminants on the colorimetry parameters of normal tongue tip color, and offer an experimental basis for standardized study of tongue color measure in TCM tongue inspection. Methods There were 35 healthy undergraduate students selected as study objects. The light source was revised to equal-energy white light (light source E of standard illuminants). The data of tongue tip color were colleted by using visible reflection spectrum method and spectrum curves (380 nm-780 nm) were obtained. The visible reflection spectrum curves under different illuminant conditions were calculated according to distribution features of spectrums A, B, C and D65 of standard illuminants. The tristimulus values of CIE XYZ color matching were calculated for getting, comparing and analyzing CIE 1964 chromaticity coordinates, dominant wavelength and RGB values of normal tongue tip color under different standard illuminant conditions.Results Under the lighting of light sources A, B, C E and D65 of standard illuminants, visible reflection spectrum curves, CIE 1964 chromaticity coordinates and red-green-blue (RGB) values of tongue tip color showed significant differences, but dominant wavelength values were consistent taking the features of standard illuminant as reference. Conclusion The material collection of tongue color inspection by using visible reflection spectrum method can provide a standardized method of color measurement. Different light source conditions of standard illuminant would cause the deviations of material collection of tongue color inspection. The application of unified light sources of standard illuminants can reduce the deviations, and at the same time, the data should be analyzed taking illuminant features as references when revising the color of digital imagine material of tongue color inspection.%目的 比较标准照明体A、B、C、E和D65光源对正常舌尖舌色色度学参数

  2. Serial millisecond crystallography of membrane and soluble protein microcrystals using synchrotron radiation

    Directory of Open Access Journals (Sweden)

    Jose M. Martin-Garcia

    2017-07-01

    Full Text Available Crystal structure determination of biological macromolecules using the novel technique of serial femtosecond crystallography (SFX is severely limited by the scarcity of X-ray free-electron laser (XFEL sources. However, recent and future upgrades render microfocus beamlines at synchrotron-radiation sources suitable for room-temperature serial crystallography data collection also. Owing to the longer exposure times that are needed at synchrotrons, serial data collection is termed serial millisecond crystallography (SMX. As a result, the number of SMX experiments is growing rapidly, with a dozen experiments reported so far. Here, the first high-viscosity injector-based SMX experiments carried out at a US synchrotron source, the Advanced Photon Source (APS, are reported. Microcrystals (5–20 µm of a wide variety of proteins, including lysozyme, thaumatin, phycocyanin, the human A2A adenosine receptor (A2AAR, the soluble fragment of the membrane lipoprotein Flpp3 and proteinase K, were screened. Crystals suspended in lipidic cubic phase (LCP or a high-molecular-weight poly(ethylene oxide (PEO; molecular weight 8 000 000 were delivered to the beam using a high-viscosity injector. In-house data-reduction (hit-finding software developed at APS as well as the SFX data-reduction and analysis software suites Cheetah and CrystFEL enabled efficient on-site SMX data monitoring, reduction and processing. Complete data sets were collected for A2AAR, phycocyanin, Flpp3, proteinase K and lysozyme, and the structures of A2AAR, phycocyanin, proteinase K and lysozyme were determined at 3.2, 3.1, 2.65 and 2.05 Å resolution, respectively. The data demonstrate the feasibility of serial millisecond crystallography from 5–20 µm crystals using a high-viscosity injector at APS. The resolution of the crystal structures obtained in this study was dictated by the current flux density and crystal size, but upcoming developments in beamline optics and the

  3. Structure of lobster apocrustacyanin A1 using softer X-rays.

    Science.gov (United States)

    Cianci, M; Rizkallah, P J; Olczak, A; Raftery, J; Chayen, N E; Zagalsky, P F; Helliwell, J R

    2001-09-01

    The molecular basis of the camouflage colouration of marine crustacea is often provided by carotenoproteins. The blue colour of the lobster carapace, for example, is intricately associated with a multimacromolecular 16-mer complex of protein subunits each with a bound astaxanthin molecule. The protein subunits of crustacyanin fall into two distinct subfamilies, CRTC and CRTA. Here, the crystal structure solution of the A(1) protein of the CRTC subfamily is reported. The problematic nature of the structure solution of the CRTC proteins (both C(1) and A(1)) warranted consideration and the development of new approaches. Three putative disulfides per protein subunit were likely to exist based on molecular-homology modelling against known lipocalin protein structures. With two such subunits per crystallographic asymmetric unit, this direct approach was still difficult as it involved detecting a weak signal from these sulfurs and suggested the use of softer X-rays, combined with high data multiplicity, as reported previously [Chayen et al. (2000), Acta Cryst. D56, 1064-1066]. This paper now describes the structure solution of CRTC in the form of the A(1) dimer based on use of softer X-rays (2 A wavelength). The structure solution involved a xenon derivative with an optimized xenon L(I) edge f" signal and a native data set. The hand of the xenon SIROAS phases was determined by using the sulfur anomalous signal from a high-multiplicity native data set also recorded at 2 A wavelength. For refinement, a high-resolution data set was measured at short wavelength. All four data sets were collected at 100 K. The refined structure to 1.4 A resolution based on 60 276 reflections has an R factor of 17.7% and an R(free) of 22.9% (3137 reflections). The structure is that of a typical lipocalin, being closely related to insecticyanin, to bilin-binding protein and to retinol-binding protein. This A(1) monomer or dimer can now be used as a search motif in the structural studies of the

  4. Ginzburg-Landau theory of the bcc-liquid interface kinetic coefficient

    Science.gov (United States)

    Wu, Kuo-An; Wang, Ching-Hao; Hoyt, Jeffrey J.; Karma, Alain

    2015-01-01

    We extend the Ginzburg-Landau (GL) theory of atomically rough bcc-liquid interfaces [Wu et al., Phys. Rev. B 73, 094101 (2006), 10.1103/PhysRevB.73.094101] outside of equilibrium. We use this extension to derive an analytical expression for the kinetic coefficient, which is the proportionality constant μ (n ̂) between the interface velocity along a direction n ̂ normal to the interface and the interface undercooling. The kinetic coefficient is expressed as a spatial integral along the normal direction of a sum of gradient square terms corresponding to different nonlinear density wave profiles. Anisotropy arises naturally from the dependence of those profiles on the angles between the principal reciprocal lattice vectors K⃗i and n ̂. Values of the kinetic coefficient for the (100 ) ,(110 ) , and (111 ) interfaces are compared quantitatively to the prediction of linear Mikheev-Chernov (MC) theory [J. Cryst. Growth 112, 591 (1991), 10.1016/0022-0248(91)90340-B] and previous molecular dynamics (MD) simulation studies of crystallization kinetics for a classical model of Fe. Additional MD simulations are carried out here to compute the relaxation time of density waves in the liquid in order to make this comparison free of fit parameters. The GL theory predicts an expression for μ similar to the MC theory but yields a better agreement with MD simulations for both its magnitude and anisotropy due to a fully nonlinear description of density wave profiles across the solid-liquid interface. In particular, the overall magnitude of μ predicted by GL theory is an order of magnitude larger than predicted by the MC theory. GL theory is also used to derive an inverse relation between μ and the solid-liquid interfacial free energy. The general methodology used here to derive an expression for μ (n ̂) also applies to amplitude equations derived from the phase-field-crystal model, which only differ from GL theory by the choice of cubic and higher order nonlinearities in the

  5. Scattering studies on cryoglobulins stability and aggregation properties

    Energy Technology Data Exchange (ETDEWEB)

    Bicev, R.N.; Oliveira, E.A.; Oliveira, C.L.P.; Brandao, H. [Universidade de Sao Paulo (USP), SP (Brazil); Andrade, L.E.C. [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil)

    2012-07-01

    configurations for the protein in solution in each temperature. [1]Dammacco F. et al. Eur J Clin Invest 2001; 31:628-38. [2]Semenyuk V and Svergun DI. J. Appl. Cryst., 1991, 24, 537-540; [3]Schmidt, Manfred; Burchard, Walter. Macromolecules, 1981, 14, 210-211 [4]Bernardo, Pau et al. Jacs, 2007, 129, 17, 5656-5664. (author)

  6. Determinants of cyanuric acid and melamine assembly in water.

    Science.gov (United States)

    Ma, Mingming; Bong, Dennis

    2011-07-19

    While the recognition of cyanuric acid (CA) by melamine (M) and their derivatives has been known to occur in both water and organic solvents for some time, analysis of CA/M assembly in water has not been reported (Ranganathan, A.; Pedireddi, V. R.; Rao, C. N. R. J. Am. Chem. Soc.1999, 121, 1752-1753; Mathias, J. P.; Simanek, E. E.; Seto, C. T.; Whitesides, G. M. Macromol. Symp.1994, 77, 157-166; Zerkowski, J. A.; MacDonald, J. C.; Seto, C. T.; Wierda, D. A.; Whitesides, G. M. J. Am. Chem. Soc.1994, 116, 2382-2391; Mathias, J. P.; Seto, C. T.; Whitesides, G. M. Polym. Prepr.1993, 34, 92-93; Seto, C. T.; Whitesides, G. M. J. Am. Chem. Soc.1993, 115, 905-916; Zerkowski, J. A.; Seto, C. T.; Whitesides, G. M. J. Am. Chem. Soc.1992, 114, 5473-5475; Seto, C. T.; Whitesides, G. M. J. Am. Chem. Soc.1990, 112, 6409-6411; Wang, Y.; Wei, B.; Wang, Q. J. Chem. Cryst.1990, 20, 79-84; ten Cate, M. G. J.; Huskens, J.; Crego-Calama, M.; Reinhoudt, D. N. Chem.-Eur. J.2004, 10, 3632-3639). We have examined assembly of CA/M, as well as assembly of soluble trivalent CA and M derivatives (TCA/TM), in aqueous solvent, using a combination of solution phase NMR, isothermal titration and differential scanning calorimetry (ITC/DSC), cryo-transmission electron microscopy (cryo-TEM), and synthetic chemistry. While the parent heterocycles coprecipitate in water, the trivalent system displays more controlled and cooperative assembly that occurs at lower concentrations than the parent and yields a stable nanoparticle suspension. The assembly of both parent and trivalent systems is rigorously 1:1 and proceeds as an exothermic, proton-transfer coupled process in neutral pH water. Though CA and M are considered canonical hydrogen-bonding motifs in organic solvents, we find that their assembly in water is driven in large part by enthalpically favorable surface-area burial, similar to what is observed with nucleic acid recognition. There are currently few synthetic systems capable of robust molecular

  7. The mechanical and strength properties of diamond.

    Science.gov (United States)

    Field, J E

    2012-12-01

    Diamond is an exciting material with many outstanding properties; see, for example Field J E (ed) 1979 The Properties of Diamond (London: Academic) and Field J E (ed) 1992 The Properties of Natural and Synthetic Diamond (London: Academic). It is pre-eminent as a gemstone, an industrial tool and as a material for solid state research. Since natural diamonds grew deep below the Earth's surface before their ejection to mineable levels, they also contain valuable information for geologists. The key to many of diamond's properties is the rigidity of its structure which explains, for example, its exceptional hardness and its high thermal conductivity. Since 1953, it has been possible to grow synthetic diamond. Before then, it was effectively only possible to have natural diamond, with a small number of these found in the vicinity of meteorite impacts. Techniques are now available to grow gem quality synthetic diamonds greater than 1 carat (0.2 g) using high temperatures and pressures (HTHP) similar to those found in nature. However, the costs are high, and the largest commercially available industrial diamonds are about 0.01 carat in weight or about 1 mm in linear dimension. The bulk of synthetic diamonds used industrially are 600 µm or less. Over 75% of diamond used for industrial purposes today is synthetic material. In recent years, there have been two significant developments. The first is the production of composites based on diamond; these materials have a significantly greater toughness than diamond while still maintaining very high hardness and reasonable thermal conductivity. The second is the production at low pressures by metastable growth using chemical vapour deposition techniques. Deposition onto non-diamond substrates was first demonstrated by Spitsyn et al 1981 J. Cryst. Growth 52 219-26 and confirmed by Matsumoto et al 1982 Japan J. Appl. Phys. 21 L183-5. These developments have added further to the versatility of diamond. Two other groups of

  8. Trinuclear nickel coordination complexes of phenanthrene-9,10-dione dioxime

    Directory of Open Access Journals (Sweden)

    Owen M. Williams

    2016-04-01

    fluoridoboronate structure, the solvent (DCM was too badly disordered to be modelled, so its contribution was removed using SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18].

  9. Skin permeability and pharmacokinetics of diclofenac epolamine administered by dermal patch in Yorkshire-Landrace pigs

    Directory of Open Access Journals (Sweden)

    Tse S

    2012-10-01

    Full Text Available Susanna Tse,1 Kendall D Powell,2 Stephen MacLennan,3 Allan R Moorman,4 Craig Paterson,5 Rosonald R Bell11Pfizer Inc, Groton, CT, USA; 2Tandem Labs, Durham, NC, USA; 3BioCryst Pharmaceuticals Inc, Durham, NC, USA; 4Alta Vetta Pharmaceutical Consulting LLC, Durham, NC, USA; 5Salix Pharmaceuticals Inc, Raleigh, NC, USAPurpose: This study compared the pharmacokinetic profile, and systemic and local absorption of diclofenac, following dermal patch application and oral administration in Yorkshire- Landrace pigs.Patients and methods: Twelve anesthetized, female, Yorkshire-Landrace pigs were randomized to receive either the dermal patch (FLECTOR® patch, 10 × 14 cm; Alpharma Pharmaceuticals, a subsidiary of Pfizer Inc, New York, NY or 50 mg oral diclofenac (Voltaren®; Novartis, East Hanover, NJ. Tissue (skin area of 2 × 2 cm and underlying muscles approximately 2–3 cm in depth and blood (10 mL samples were collected at timed intervals up to 11.5 hours after initial patch application or oral administration. The concentrations of diclofenac in plasma, skin, and muscle samples were analyzed using validated ultra performance liquid chromatography tandem mass spectrometric methods.Results: Peak systemic exposure of diclofenac was very low by dermal application compared with oral administration (maximum concentration [Cmax] values of 3.5 vs 9640 ng/mL, respectively. Absorption of diclofenac into underlying muscles beneath the dermal patch was sustained, and followed apparently zero-order kinetics, with the skin serving as a depot with elevated concentrations of diclofenac. Concentrations of diclofenac in muscles beneath the patch application site were similar to corresponding tissues after oral administration (Cmax values of 879 and 1160 ng/mL, respectively. In contrast to the wide tissue distribution of diclofenac after oral administration, dermal patch application resulted in high concentrations of diclofenac only on the treated skin and immediate

  10. Crystal structures of a copper(II and the isotypic nickel(II and palladium(II complexes of the ligand (E-1-[(2,4,6-tribromophenyldiazenyl]naphthalen-2-ol

    Directory of Open Access Journals (Sweden)

    Souheyla Chetioui

    2016-08-01

    Full Text Available In the copper(II complex, bis{(E-1-[(2,4,6-tribromophenyldiazenyl]naphthalen-2-olato}copper(II, [Cu(C16H8Br3N2O2], (I, the metal cation is coordinated by two N atoms and two O atoms from two bidentate (E-1-[(2,4,6-tribromophenyldiazenyl]naphthalen-2-olate ligands, forming a slightly distorted square-planar environment. In one of the ligands, the tribromobenzene ring is inclined to the naphthalene ring system by 37.4 (5°, creating a weak intramolecular Cu...Br interaction [3.134 (2 Å], while in the other ligand, the tribromobenzene ring is inclined to the naphthalene ring system by 72.1 (6°. In the isotypic nickel(II and palladium(II complexes, namely bis{(E-1-[(2,4,6-tribromophenyldiazenyl]naphthalen-2-olato}nickel(II, [Ni(C16H8Br3N2O2], (II, and bis{(E-1-[(2,4,6-tribromophenyldiazenyl]naphthalen-2-olato}palladium(II, [Pd(C16H8Br3N2O2], (III, respectively, the metal atoms are located on centres of inversion, hence the metal coordination spheres have perfect square-planar geometries. The tribromobenzene rings are inclined to the naphthalene ring systems by 80.79 (18° in (II and by 80.8 (3° in (III. In the crystal of (I, molecules are linked by C—H...Br hydrogen bonds, forming chains along [010]. The chains are linked by C—H...π interactions, forming sheets parallel to (011. In the crystals of (II and (III, molecules are linked by C—H...π interactions, forming slabs parallel to (10-1. For the copper(II complex (I, a region of disordered electron density was corrected for using the SQUEEZE routine in PLATON [Spek (2015. Acta Cryst. C71, 9–18]. The formula mass and unit-cell characteristics of the disordered solvent molecules were not taken into account during refinement.

  11. Crystal structures of N2,N3,N5,N6-tetrakis(pyridin-2-ylmethylpyrazine-2,3,5,6-tetracarboxamide and N2,N3,N5,N6-tetrakis(pyridin-4-ylmethylpyrazine-2,3,5,6-tetracarboxamide

    Directory of Open Access Journals (Sweden)

    Dilovan S. Cati

    2017-02-01

    Full Text Available The title compounds, C32H28N10O4· unknown solvent, (I, and C32H28N10O4, (II, are pyrazine-2,3,5,6-tetracarboxamide derivatives. In (I, the substituents are (pyridin-2-ylmethylcarboxamide, while in (II, the substituents are (pyridin-4-ylmethylcarboxamide. Both compounds crystallize in the monoclinic space group P21/n, with Z′ = 1 for (I, and Z′ = 0.5 for (II. The whole molecule of (II is generated by inversion symmetry, the pyrazine ring being situated about a center of inversion. In (I, the four pyridine rings are inclined to the pyrazine ring by 83.9 (2, 82.16 (18, 82.73 (19 and 17.65 (19°. This last dihedral angle involves a pyridine ring that is linked to the adjacent carboxamide O atom by an intramolecular C—H...O hydrogen bond. In compound (II, the unique pyridine rings are inclined to the pyrazine ring by 33.3 (3 and 81.71 (10°. There are two symmetrical intramolecular C—H...O hydrogen bonds present in (II. In the crystal of (I, molecules are linked by N—H...O and N—H...N hydrogen bonds, forming layers parallel to (10-1. The layers are linked by C—H...O and C—H...N hydrogen bonds, forming a three-dimensional framework. In the crystal of (II, molecules are linked by N—H...N hydrogen bonds, forming chains propagating along the [010] direction. The chains are linked by a weaker N—H...N hydrogen bond, forming layers parallel to the (101 plane, which are in turn linked by C—H...O hydrogen bonds, forming a three-dimensional structure. In the crystal of compound (I, a region of disordered electron density was treated with the SQUEEZE routine in PLATON [Spek (2015. Acta Cryst. C71, 9–18]. Their contribution was not taken into account during refinement. In compound (II, one of the pyridine rings is positionally disordered, and the refined occupancy ratio for the disordered Car—Car—Npy atoms is 0.58 (3:0.42 (3.

  12. Crystal structures of tris[1-oxopyridine-2-olato(1−]silicon(IV chloride chloroform-d1 disolvate, tris[1-oxopyridine-2-olato(1−]silicon(IV chloride acetonitrile unquantified solvate, and fac-tris[1-oxopyridine-2-thiolato(1−]silicon(IV chloride chloroform-d1 disolvate

    Directory of Open Access Journals (Sweden)

    Bradley M. Kraft

    2015-12-01

    Full Text Available The cations in the title salts, [Si(OPO3]Cl·2CDCl3, (I, [Si(OPO3]Cl·xCH3CN, (II, and fac-[Si(OPTO3]Cl·2CDCl3, (III (OPO = 1-oxo-2-pyridinone, C5H4NO2, and OPTO = 1-oxo-2-pyridinethione, C5H4NOS, have distorted octahedral coordination spheres. The first two structures contain the same cation and anion, but different solvents of crystallization led to different solvates and packing arrangements. In structures (I and (III, the silicon complex cations and chloride anions are well separated, while in (II, there are two C—H...Cl distances that fall just within the sum of the van der Waals radii of the C and Cl atoms. The pyridine portions of the OPO ligands in (I and (II are modeled as disordered with the planar flips of themselves [(I: 0.574 (15:0.426 (15, 0.696 (15:0.304 (15, and 0.621 (15:0.379 (15; (II: 0.555 (13:0.445 (13, 0.604 (14:0.396 (14 and 0.611 (13:0.389 (13], demonstrating that both fac and mer isomers are co-crystallized. In (II, highly disordered solvent, located in two independent channels along [100], was unable to be modeled. Reflection contributions from this solvent were fixed and added to the calculated structure factors using the SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] function of program PLATON, which determined there to be 54 electrons in 225 Å3 accounted for per unit cell (25 electrons in 109 Å3 in one channel, and 29 electrons in 115 Å3 in the other. In (I and (II, all species lie on general positions. In (III, all species are located along crystallographic threefold axes.

  13. Chelate Ring Size Effect as a Factor of Selective Fluorescent Recognition of Zn(2+) Ions by Pyrrolo[2,3-b]quinoxaline with a Substituted 2-Pyridyl Group Receptor.

    Science.gov (United States)

    Ostrowska, Katarzyna; Musielak, Bogdan; Szneler, Edward; Dudek, Łukasz; Gryl, Marlena; Stadnicka, Katarzyna

    2015-09-01

    Analysis of the spectral properties and structural differences of two turn-on ratiometric fluorescent receptors for Zn(2+) and Cd(2+) ions, derivatives of pyrrolo[2,3-b]quinoxaline (2), and earlier published 3 (Ostrowska et al. CrystEngComm 2015, 17, 498-502) was performed. Both ligands are E/Z push-pull olefins interconverting at room temperature, with barriers to rotation about enamine double bonds, from E to Z isomers of 19.3 ± 0.1 and 16.9 ± 0.3 kcal/mol and from Z to E of 16.9 ± 0.3 and 15.7 ± 0.2 kcal/mol, respectively. Diastereoisomers (E)-2 and (Z)-2 were isolated and characterized by X-ray structural analysis. The formation of complexes by (E/Z)-2 with acetates and acetylacetonates of Zn(2+) and Cd(2+) was monitored by UV-vis, fluorescence, and (1)H NMR titrations in acetonitrile, respectively. X-ray structural analysis for isolated [(E)-2]2Zn in relation to earlier published (E)-3-ZnOAc revealed the formation of a six-coordinated zinc ion with six- and four-membered bis-chelate rings by (E)-2. The chelate effect increases the ligand affinity for Zn(2+) (log β12 = 12.45) and causes the elongation of nitrogen-metal bonds. Extension of the coordination cavity size allows coordination of a cadmium ion. The introduction of a flexible ethylene linker between the fluorophore and ionophore pyridyl groups in 3 significantly affects the selectivity of zinc-ion recognition. The distorted tetrahedral geometry of (E)-3-ZnOAc with a four-coordinated zinc ion appears to be the most preferred because of the short donor-zinc distance with a 1:1 binding mode. The formation of the small coordination cavity size with six-membered bis-chelate rings provides an effective overlap of zinc and donor orbitals, precluding the coordination of a cadmium ion in the same manner as zinc.

  14. Polarised neutron scattering from dynamic polarised targets in biology

    Science.gov (United States)

    Knop, W.; Hirai, M.; Olah, G.; Meerwinck, W.; Schink, H.-J.; Stuhrman, H. B.; Wagner, R.; Wenkow-EsSouni, M.; Zhao, J.; Schärpf, O.; Crichton, R. R.; Krumpolc, M.; Nierhaus, K. H.; Niinikoski, T. O.; Rijllart, A.

    1991-10-01

    The contrast giving rise to neutron small-angle scattering can be enhanced considerably by polarisation of the hydrogen nuclei [J. des Coizeaux and G. Jannink, Les Polymères en Solution, Les Editions de Physique, F-91944 Les Ulis, France (1987)]. Using polarised neutrons the scattering from protonated labels in a deuterated matrix will increase by an order of magnitude. This is the basis of nuclear spin contrast variation, a method which is of particular interest for the in situ structure determination of macromolecular components. A new polarised target for neutron scattering has been designed by CERN and tested successfully at FRG-1 of the GKSS research centre. For the purpose of thermal-neutron scattering the frozen solutions of biomolecules are immersed in liquid helium 4, which is thermally coupled to the cooling mixture of helium 3/helium 4 of the dilution refrigerator. The nuclear spins are aligned with respect to the external magnetic field-parallel or antiparallel-by dynamic nuclear polarisation (DNP). The gain in neutron scattering compared to earlier experiments using direct cooling of the sample by helium 3 is a factor of 30. Another factor of 30 arises from the installation of the cold source and the beryllium reflector in FRG-1 [W. Knop et al., J. Appl. Cryst. 22 (1989) 352]. Pure nuclear spin targets are produced from dynamic polarised targets by selective depolarisation. In biological material only the hydrogen isotopes contribute significantly to polarised neutron scattering. Thus, saturation of the proton NMR yields a deuteron target, provided the target material has been enriched by the latter isotope. A proton target is obtained from the dynamic polarised target by saturation of deuteron NMR. This leads to six additional scattering functions reflecting the proton and deuteron spin densities and the correlations between the polarised isotopes. Polarised neutron scattering from nuclear spin targets of apoferritin and various derivatives of the

  15. Crystal structures of tris-[1-oxo-pyridine-2-olato(1-)]silicon(IV) chloride chloro-form-d 1 disolvate, tris-[1-oxo-pyridine-2-olato(1-)]silicon(IV) chloride aceto-nitrile unqu-anti-fied solvate, and fac-tris-[1-oxo-pyridine-2-thiol-ato(1-)]silicon(IV) chloride chloro-form-d 1 disolvate.

    Science.gov (United States)

    Kraft, Bradley M; Brennessel, William W; Ryan, Amy E; Benjamin, Candace K

    2015-12-01

    The cations in the title salts, [Si(OPO)3]Cl·2CDCl3, (I), [Si(OPO)3]Cl·xCH3CN, (II), and fac-[Si(OPTO)3]Cl·2CDCl3, (III) (OPO = 1-oxo-2-pyridin-one, C5H4NO2, and OPTO = 1-oxo-2-pyridine-thione, C5H4NOS), have distorted octa-hedral coordination spheres. The first two structures contain the same cation and anion, but different solvents of crystallization led to different solvates and packing arrangements. In structures (I) and (III), the silicon complex cations and chloride anions are well separated, while in (II), there are two C-H⋯Cl distances that fall just within the sum of the van der Waals radii of the C and Cl atoms. The pyridine portions of the OPO ligands in (I) and (II) are modeled as disordered with the planar flips of themselves [(I): 0.574 (15):0.426 (15), 0.696 (15):0.304 (15), and 0.621 (15):0.379 (15); (II): 0.555 (13):0.445 (13), 0.604 (14):0.396 (14) and 0.611 (13):0.389 (13)], demonstrating that both fac and mer isomers are co-crystallized. In (II), highly disordered solvent, located in two independent channels along [100], was unable to be modeled. Reflection contributions from this solvent were fixed and added to the calculated structure factors using the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9-18] function of program PLATON, which determined there to be 54 electrons in 225 Å(3) accounted for per unit cell (25 electrons in 109 Å(3) in one channel, and 29 electrons in 115 Å(3) in the other). In (I) and (II), all species lie on general positions. In (III), all species are located along crystallographic threefold axes.

  16. Crystal structures of a copper(II) and the isotypic nickel(II) and palladium(II) complexes of the ligand (E)-1-[(2,4,6-tri­bromo­phen­yl)diazen­yl]naphthalen-2-ol

    Science.gov (United States)

    Chetioui, Souheyla; Rouag, Djamil-Azzeddine; Djukic, Jean-Pierre; Bochet, Christian G.; Touzani, Rachid; Bailly, Corinne; Crochet, Aurélien; Fromm, Katharina M.

    2016-01-01

    In the copper(II) complex, bis­{(E)-1-[(2,4,6-tri­bromo­phen­yl)diazen­yl]naph­thalen-2-olato}copper(II), [Cu(C16H8Br3N2O)2], (I), the metal cation is coord­inated by two N atoms and two O atoms from two bidentate (E)-1-[(2,4,6-tri­bromo­phen­yl)diazen­yl]naphthalen-2-olate ligands, forming a slightly distorted square-planar environment. In one of the ligands, the tri­bromo­benzene ring is inclined to the naphthalene ring system by 37.4 (5)°, creating a weak intra­molecular Cu⋯Br inter­action [3.134 (2) Å], while in the other ligand, the tri­bromo­benzene ring is inclined to the naphthalene ring system by 72.1 (6)°. In the isotypic nickel(II) and palladium(II) complexes, namely bis­{(E)-1-[(2,4,6-tri­bromo­phen­yl)diazen­yl]naphthalen-2-olato}nickel(II), [Ni(C16H8Br3N2O)2], (II), and bis­{(E)-1-[(2,4,6-tri­bromo­phen­yl)diazen­yl]naphthalen-2-olato}palladium(II), [Pd(C16H8Br3N2O)2], (III), respectively, the metal atoms are located on centres of inversion, hence the metal coordination spheres have perfect square-planar geometries. The tri­bromo­benzene rings are inclined to the naphthalene ring systems by 80.79 (18)° in (II) and by 80.8 (3)° in (III). In the crystal of (I), mol­ecules are linked by C—H⋯Br hydrogen bonds, forming chains along [010]. The chains are linked by C—H⋯π inter­actions, forming sheets parallel to (011). In the crystals of (II) and (III), mol­ecules are linked by C—H⋯π inter­actions, forming slabs parallel to (10-1). For the copper(II) complex (I), a region of disordered electron density was corrected for using the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9–18]. The formula mass and unit-cell characteristics of the disordered solvent mol­ecules were not taken into account during refinement. PMID:27536389

  17. Crystal structures of a copper(II) and the isotypic nickel(II) and palladium(II) complexes of the ligand (E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-ol.

    Science.gov (United States)

    Chetioui, Souheyla; Rouag, Djamil-Azzeddine; Djukic, Jean-Pierre; Bochet, Christian G; Touzani, Rachid; Bailly, Corinne; Crochet, Aurélien; Fromm, Katharina M

    2016-08-01

    In the copper(II) complex, bis-{(E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naph-thalen-2-olato}copper(II), [Cu(C16H8Br3N2O)2], (I), the metal cation is coord-inated by two N atoms and two O atoms from two bidentate (E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-olate ligands, forming a slightly distorted square-planar environment. In one of the ligands, the tri-bromo-benzene ring is inclined to the naphthalene ring system by 37.4 (5)°, creating a weak intra-molecular Cu⋯Br inter-action [3.134 (2) Å], while in the other ligand, the tri-bromo-benzene ring is inclined to the naphthalene ring system by 72.1 (6)°. In the isotypic nickel(II) and palladium(II) complexes, namely bis-{(E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-olato}nickel(II), [Ni(C16H8Br3N2O)2], (II), and bis-{(E)-1-[(2,4,6-tri-bromo-phen-yl)diazen-yl]naphthalen-2-olato}palladium(II), [Pd(C16H8Br3N2O)2], (III), respectively, the metal atoms are located on centres of inversion, hence the metal coordination spheres have perfect square-planar geometries. The tri-bromo-benzene rings are inclined to the naphthalene ring systems by 80.79 (18)° in (II) and by 80.8 (3)° in (III). In the crystal of (I), mol-ecules are linked by C-H⋯Br hydrogen bonds, forming chains along [010]. The chains are linked by C-H⋯π inter-actions, forming sheets parallel to (011). In the crystals of (II) and (III), mol-ecules are linked by C-H⋯π inter-actions, forming slabs parallel to (10-1). For the copper(II) complex (I), a region of disordered electron density was corrected for using the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The formula mass and unit-cell characteristics of the disordered solvent mol-ecules were not taken into account during refinement.

  18. Crystal structures of N(2),N(3),N(5),N(6)-tetra-kis-(pyridin-2-ylmeth-yl)pyrazine-2,3,5,6-tetra-carboxamide and N(2),N(3),N(5),N(6)-tetra-kis-(pyridin-4-ylmeth-yl)pyrazine-2,3,5,6-tetra-carboxamide.

    Science.gov (United States)

    Cati, Dilovan S; Stoeckli-Evans, Helen

    2017-02-01

    The title compounds, C32H28N10O4· unknown solvent, (I), and C32H28N10O4, (II), are pyrazine-2,3,5,6-tetra-carboxamide derivatives. In (I), the substituents are (pyridin-2-ylmeth-yl)carboxamide, while in (II), the substituents are (pyridin-4-ylmeth-yl)carboxamide. Both compounds crystallize in the monoclinic space group P21/n, with Z' = 1 for (I), and Z' = 0.5 for (II). The whole mol-ecule of (II) is generated by inversion symmetry, the pyrazine ring being situated about a center of inversion. In (I), the four pyridine rings are inclined to the pyrazine ring by 83.9 (2), 82.16 (18), 82.73 (19) and 17.65 (19)°. This last dihedral angle involves a pyridine ring that is linked to the adjacent carboxamide O atom by an intra-molecular C-H⋯O hydrogen bond. In compound (II), the unique pyridine rings are inclined to the pyrazine ring by 33.3 (3) and 81.71 (10)°. There are two symmetrical intra-molecular C-H⋯O hydrogen bonds present in (II). In the crystal of (I), mol-ecules are linked by N-H⋯O and N-H⋯N hydrogen bonds, forming layers parallel to (10-1). The layers are linked by C-H⋯O and C-H⋯N hydrogen bonds, forming a three-dimensional framework. In the crystal of (II), mol-ecules are linked by N-H⋯N hydrogen bonds, forming chains propagating along the [010] direction. The chains are linked by a weaker N-H⋯N hydrogen bond, forming layers parallel to the (101) plane, which are in turn linked by C-H⋯O hydrogen bonds, forming a three-dimensional structure. In the crystal of compound (I), a region of disordered electron density was treated with the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. Their contribution was not taken into account during refinement. In compound (II), one of the pyridine rings is positionally disordered, and the refined occupancy ratio for the disordered Car-Car-Npy atoms is 0.58 (3):0.42 (3).

  19. Crystal structure of an unknown solvate of dodecakis(μ2-alaninato-1:2κ2O:N,Ocerium(IIIhexanickel(II aquatris(hydroxido-κOtris(nitrato-κ2O,O′cerate(III

    Directory of Open Access Journals (Sweden)

    Stanislav I. Bezzubov

    2015-10-01

    Full Text Available The chiral title compound, [CeNi6(C3H6NO212][Ce(NO33(OH3(H2O], comprises a complex heterometallic Ni/Ce cation and a homonuclear Ce anion. Both the cation and anion exhibit point group symmetry 3. with the CeIII atom situated on the threefold rotation axis. The cation metal core consists of six NiII atoms coordinated in a slightly distorted octahedral N2O4 configuration by N and O atoms of 12 deprotonated l-alaninate ligands exhibiting both bridging and chelating modes. This metal–organic coordination motif encapsulates one CeIII atom that shows an icosahedral coordination by the O-donor atoms of the l-alaninate ligands, with Ce—O distances varying in the range 2.455 (5–2.675 (3 Å. In the anion, the central CeIII ion is bound to three bidentate nitrate ligands, to three hydroxide ligands and to one water molecule, with Ce—O distances in the range 2.6808 (19–2.741 (2 Å. The H atoms of the coordinating water molecule are disordered over three positions due to its location on a threefold rotation axis. Disorder is also observed in fragments of two l-alaninate ligands, with occupancy ratios of 0.608 (14:0.392 (14 and 0.669 (8:0.331 (8, respectively, for the two sets of sites. In the crystal, the complex cations and anions assemble through O—H...O and N—H...O hydrogen bonds into a three-dimensional network with large voids of approximately 1020 Å3. The contributions of highly disordered ethanol and water solvent molecules to the diffraction data were removed with the SQUEEZE procedure [Spek (2015. Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unknown amount of these solvent molecules.

  20. Crystal structure of lactoperoxidase at 2.4 A resolution.

    Science.gov (United States)

    Singh, Amit Kumar; Singh, Nagendra; Sharma, Sujata; Singh, S Baskar; Kaur, Punit; Bhushan, A; Srinivasan, A; Singh, Tej P

    2008-02-29

    Lactoperoxidase (LPO) is a member of the mammalian peroxidase superfamily. It catalyzes the oxidation of thiocyanate and halides. Freshly isolated and purified samples of caprine LPO were saturated with ammonium iodide and crystallized using 20% polyethylene glycol 3350 in a hanging drop vapor diffusion setup. The structure has been determined using X-ray crystallographic method and refined to R(cryst) and R(free) factors of 0.196 and 0.203, respectively. The structure determination revealed an unexpected phosphorylation of Ser198 in LPO, which is also confirmed by anti-phosphoserine antibody binding studies. The structure is also notable for observing densities for glycan chains at all the four potential glycosylation sites. Caprine LPO consists of a single polypeptide chain of 595 amino acid residues and folds into an oval-shaped structure. The structure contains 20 well-defined alpha-helices of varying lengths including a helix, H(2a), unique to LPO, and two short antiparallel beta-strands. The structure confirms that the heme group is covalently linked to the protein through two ester linkages involving carboxylic groups of Glu258 and Asp108 and modified methyl groups of pyrrole rings A and C, respectively. The heme moiety is slightly distorted from planarity, but pyrrole ring B is distorted considerably. However, an iron atom is displaced only by 0.1 A from the plane of the heme group toward the proximal site. The substrate diffusing channel in LPO is cylindrical in shape with a diameter of approximately 6 A. Two histidine residues and six buried water molecules are connected through a hydrogen-bonded chain from the distal heme cavity to the surface of protein molecule and seemingly form the basis of proton relay for catalytic action. Ten iodide ions have been observed in the structure. Out of these, only one iodide ion is located in the distal heme cavity and is hydrogen bonded to the water molecule W1. W1 is also hydrogen bonded to the heme iron as well as

  1. PLATON SQUEEZE: a tool for the calculation of the disordered solvent contribution to the calculated structure factors.

    Science.gov (United States)

    Spek, Anthony L

    2015-01-01

    The completion of a crystal structure determination is often hampered by the presence of embedded solvent molecules or ions that are seriously disordered. Their contribution to the calculated structure factors in the least-squares refinement of a crystal structure has to be included in some way. Traditionally, an atomistic solvent disorder model is attempted. Such an approach is generally to be preferred, but it does not always lead to a satisfactory result and may even be impossible in cases where channels in the structure are filled with continuous electron density. This paper documents the SQUEEZE method as an alternative means of addressing the solvent disorder issue. It conveniently interfaces with the 2014 version of the least-squares refinement program SHELXL [Sheldrick (2015). Acta Cryst. C71. In the press] and other refinement programs that accept externally provided fixed contributions to the calculated structure factors. The PLATON SQUEEZE tool calculates the solvent contribution to the structure factors by back-Fourier transformation of the electron density found in the solvent-accessible region of a phase-optimized difference electron-density map. The actual least-squares structure refinement is delegated to, for example, SHELXL. The current versions of PLATON SQUEEZE and SHELXL now address several of the unnecessary complications with the earlier implementation of the SQUEEZE procedure that were a necessity because least-squares refinement with the now superseded SHELXL97 program did not allow for the input of fixed externally provided contributions to the structure-factor calculation. It is no longer necessary to subtract the solvent contribution temporarily from the observed intensities to be able to use SHELXL for the least-squares refinement, since that program now accepts the solvent contribution from an external file (.fab file) if the ABIN instruction is used. In addition, many twinned structures containing disordered solvents are now also

  2. Polymorphism of NaVO2F2: a P2₁/c superstructure with pseudosymmetry of P2₁/m in the subcell.

    Science.gov (United States)

    Yu, Zi-Qun; Wang, Jing-Quan; Huang, Ya-Xi; Botis, Sanda M; Pan, Yuanming; Mi, Jin-Xiao

    2015-06-01

    The ADDSYM routine in the program PLATON [Spek (2015). Acta Cryst. C71, 9-18] has helped researchers to avoid structures of (metal-)organic compounds being reported in an unnecessarily low symmetry space group. However, determination of the correct space group may get more complicated in cases of pseudosymmetric inorganic compounds. One example is NaVO2F2, which was reported [Crosnier-Lopez et al. (1994). Eur. J. Solid State Inorg. Chem. 31, 957-965] in the acentric space group P2₁ based on properties but flagged by ADDSYM as (pseudo)centrosymmetric P2₁/m within default distance tolerances. Herein a systematic investigation reveals that NaVO2F2 exists in at least four polymorphs: P2₁, (I), P2₁/m, (II), P2₁/c, (III), and one or more low-temperature ones. The new centrosymmetric modification, (III), with the space group P2₁/c has a similar atomic packing geometry to phase (I), except for having a doubled c axis. The double-cell of phase (III) arises from atomic shifts from the glide plane c at (x, ¼, z). With increasing temperature, the number of observed reflections decreases. The odd l reflections gradually become weaker and, correspondingly, all atoms shift towards the glide plane, resulting in a gradual second-order transformation of (III) into high-temperature phase (II) (P2₁/m) at below 493 K. At least one first-order enantiotropic phase transition was observed below 139 K from both the single-crystal X-ray diffraction and the differential scanning calorimetry analyses. Periodic first-principles calculations within density functional theory show that both P2₁/c superstructure (III) and P2₁ substructure (I) are more stable than P2₁/m structure (II), and that P2₁/c superstructure (III) is more stable that P2₁ substructure (I).

  3. Crystal structures of N 2,N 3,N 5,N 6-tetra­kis­(pyridin-2-ylmeth­yl)pyrazine-2,3,5,6-tetra­carboxamide and N 2,N 3,N 5,N 6-tetra­kis­(pyridin-4-ylmeth­yl)pyrazine-2,3,5,6-tetra­carboxamide

    Science.gov (United States)

    Cati, Dilovan S.; Stoeckli-Evans, Helen

    2017-01-01

    The title compounds, C32H28N10O4· unknown solvent, (I), and C32H28N10O4, (II), are pyrazine-2,3,5,6-tetra­carboxamide derivatives. In (I), the substituents are (pyridin-2-ylmeth­yl)carboxamide, while in (II), the substituents are (pyridin-4-ylmeth­yl)carboxamide. Both compounds crystallize in the monoclinic space group P21/n, with Z′ = 1 for (I), and Z′ = 0.5 for (II). The whole mol­ecule of (II) is generated by inversion symmetry, the pyrazine ring being situated about a center of inversion. In (I), the four pyridine rings are inclined to the pyrazine ring by 83.9 (2), 82.16 (18), 82.73 (19) and 17.65 (19)°. This last dihedral angle involves a pyridine ring that is linked to the adjacent carboxamide O atom by an intra­molecular C—H⋯O hydrogen bond. In compound (II), the unique pyridine rings are inclined to the pyrazine ring by 33.3 (3) and 81.71 (10)°. There are two symmetrical intra­molecular C—H⋯O hydrogen bonds present in (II). In the crystal of (I), mol­ecules are linked by N—H⋯O and N—H⋯N hydrogen bonds, forming layers parallel to (10-1). The layers are linked by C—H⋯O and C—H⋯N hydrogen bonds, forming a three-dimensional framework. In the crystal of (II), mol­ecules are linked by N—H⋯N hydrogen bonds, forming chains propagating along the [010] direction. The chains are linked by a weaker N—H⋯N hydrogen bond, forming layers parallel to the (101) plane, which are in turn linked by C—H⋯O hydrogen bonds, forming a three-dimensional structure. In the crystal of compound (I), a region of disordered electron density was treated with the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9–18]. Their contribution was not taken into account during refinement. In compound (II), one of the pyridine rings is positionally disordered, and the refined occupancy ratio for the disordered Car—Car—Npy atoms is 0.58 (3):0.42 (3). PMID:28217363

  4. Crystal structures of three 4-substituted-2,2′-bipyridines synthesized by Sonogashira and Suzuki–Miyaura cross-coupling reactions

    Science.gov (United States)

    Luong Thi Thu, Thuy; Nguyen Bich, Ngan; Nguyen, Hien

    2017-01-01

    Facile synthetic routes for three 4-substituted 2,2′-bi­pyridine derivatives, 4-[2-(4-methyl­phenyl)­ethyn­yl]-2,2′-bi­pyridine, C19H14N2, (I), 4-[2-(pyridin-3-yl)ethyn­yl]-2,2′-bi­pyridine, C17H11N3, (II), and 4-(indol-4-yl)-2,2′-bi­pyridine, C18H13N3, (III), via Sonogashira and Suzuki–Miyaura cross-coupling reactions, respect­ively, are described. As indicated by X-ray analysis, the 2,2′-bi­pyridine core, the ethyl­ene linkage and the substituents of (I) and (II) are almost planar [dihedral angles between the two ring systems: 8.98 (5) and 9.90 (6)° for the two mol­ecules of (I) in the asymmetric unit and 2.66 (14)° for (II)], allowing π-conjugation. On the contrary, in (III), the indole substituent ring is rotated significantly out of the bi­pyridine plane [dihedral angle = 55.82 (3)°], due to steric hindrance. The crystal packings of (I) and (II) are dominated by π–π inter­actions, resulting in layers of mol­ecules parallel to (30-2) in (I) and columns of mol­ecules along the a axis in (II). The packing of (III) exhibits zigzag chains of mol­ecules along the c axis inter­acting through N—H⋯N hydrogen bonds and π–π inter­actions. The contributions of unknown disordered solvent mol­ecules to the diffraction intensities in (II) were removed with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9–18] algorithm of PLATON. The given chemical formula and other crystal data do not take into account these solvent mol­ecules. PMID:28435732

  5. Three new [XC(O)NH]P(O)[N(CH2C6H5)2]2 phosphoric triamides (X = CClF2, 3-F-C6H4 and 3,5-F2-C6H3): a database analysis of tertiary N-atom geometry in compounds with a C(O)NHP(O)[N]2 core.

    Science.gov (United States)

    Pourayoubi, Mehrdad; Jasinski, Jerry P; Shoghpour Bayraq, Samad; Eshghi, Hossein; Keeley, Amanda C; Bruno, Giuseppe; Amiri Rudbari, Hadi

    2012-10-01

    In the phosphoric triamides N,N,N',N'-tetrabenzyl-N''-(2-chloro-2,2-difluoroacetyl)phosphoric triamide, C(30)H(29)ClF(2)N(3)O(2)P, (I), N,N,N',N'-tetrabenzyl-N''-(3-fluorobenzoyl)phosphoric triamide, C(35)H(33)FN(3)O(2)P, (II), and N,N,N',N'-tetrabenzyl-N''-(3,5-difluorobenzoyl)phosphoric triamide, C(35)H(32)F(2)N(3)O(2)P, (III), the tertiary N atoms of the dibenzylamido groups have sp(2) character with minimal deviation from planarity. The sums of the three bond angles about the N atoms in (I)-(III) deviate by less than 8° from the planar value of 360°. The geometries of the tertiary N atoms in all phosphoric triamides with C(O)NHP(O)[N](2) skeletons deposited in the Cambridge Structural Database [CSD; Allen (2002). Acta Cryst. B58, 380-388] have been examined and the bond-angle sums at the two tertiary N atoms (SUM1 and SUM2) and the parameter ΔSUM (= SUM1 - SUM2) considered. It was found that in compounds with a considerable ΔSUM value, the more pyramidal N atoms are usually oriented so that the corresponding lone electron pair is anti with respect to the P=O group. In (I), (II) and (III), the phosphoryl and carbonyl groups, separated by an N atom, are anti with respect to each other. In the C(O)NHP(O) fragment of (I)-(III), the P-N bond is longer and the O-P-N angle is contracted compared with the other two P-N bonds and the O-P-N angles in the molecules. These effects are also seen in analogous compounds deposited in the CSD. Compounds with [C(O)NH]P(O)[N]X (X ≠ N), such as compounds with a [C(O)NH]P(O)[N][O] skeleton, have not been considered here. Also, compounds with a [C(O)NH](2)P(O)[N] fragment have not been reported to date. In the crystal structures of all three title compounds, adjacent molecules are linked via pairs of P=O···H-N hydrogen bonds, forming dimers with C(i) symmetry.

  6. Nanoscale observations of the effect of citrate on calcium oxalate precipitation on calcite surfaces.

    Science.gov (United States)

    Burgos-Cara, Alejandro; Ruiz-Agudo, Encarnacion; Putnis, Christine V.

    2016-04-01

    . Inhibition of calcium oxalate monohydrate growth by citrate and the effect of the background electrolyte. J Cryst Growth 2007;306:135-45.

  7. Spectrum-tunable Distribution and Spectral Matching for Integrating Sphere Light Source Based on Bromine Tungsten Lamps and LEDs%基于溴钨灯和LED积分球光源的可调谐光谱分布及光谱匹配

    Institute of Scientific and Technical Information of China (English)

    刘洪兴; 任建伟; 李葆勇; 李宪圣; 万志; 赵文才

    2011-01-01

    The mixed-lamps of bromine tungsten lamps and LEDs were proposed to serve as integrating sphere inner source and LEDs were driven by constant current. Simulated Annealing (SA) algorithm was introduced to study the spectral matching technique of spectrum-tunable integrating sphere light source ( STIS ). The simulation experiment indicated that mixed-lamps could not only mimic CIE-D65 and equi-energy spectra successfully, but also improve the performance of STIS. The numbers of LEDs reducing 79. 8% and 82. 9% , respec- tively, and the average-relative error reducing 10% and 40.5% , comparied with LEDs simulation results. A feasible mixed-lamps scheme for Φ0.5 m integrating sphere, whose maximal radiance between 380 nm and 900 nm is no less than 50 W/(m2 · sr). The validating experiment indicated that the SA algorithm and constant current drive mode would be feasible in STIS' engineering practice.%采用溴钨灯和恒流驱动的LED混合作为积分球内部光源,提出了模拟退火算法作为光谱匹配算法,研究了光谱分布可调谐积分球光源的光谱匹配技术.仿真实验表明,该混合光源完全能够定量地模拟CIE-D65和等能光谱分布,且在辐射功率优于LED模拟结果的前提下,LED的数量分别减少79.8%和82.9%,平均相对误差分别减小10%和40.5%.给出了380~900 nm波段最大输出辐亮度不低于50W/(m2·sr)的直径为0.5m的光谱分布可调谐积分球光源的混光方案.实验表明,模拟退火算法和恒流驱动方案可应用于光谱分布可调谐积分球光源的工程实践.

  8. Definitions and Analysis of The Contrast of The E-book Reader%反射式电子书阅读器对比度的定义及测试分析

    Institute of Scientific and Technical Information of China (English)

    黄葭蓓; 徐艳芳

    2009-01-01

    为了对反射式电子阅读器的显示质量进行合理测评,本文探讨了3种常用的D65光源、D50光源和A光源下不同对比度的定义:计量材料本身的光谱行为的对比度定义为反射率对比度Cρ;计量材料的反光行为和人眼的接收特性的对比度定义为反射率视觉对比度CV;计量材料本身的光谱行为,同时计量光源和人眼的光谱光效特性的对比度定义为亮度对比度CL.通过测试实验选择的电子阅读器产品分析不同对比度之间的关联特性.实验结果表明,在常用光源下,CL和CV线性相关,在表征该类阅读器的黑白对比度性能上具有等同的作用,考虑到CL进一步可用于衡量黑白对比度的绝对大小.%In order to evaluate the display quality of E-book reader reasonably, The different definitions of the contrast for three commonly used light source D65,D50 and A were discussed: the contrast of the spectral behavior of is defined as reflectance contrast Cρ, which only related to the measurement of the material itself; The contrast of reflectance contrast of the materials and receiving characteristics of human eyes is defined as CV(visual contrast) which related to the measurement of both the reflective material and the receiving characteristics of the human eyes; the brightness contrast is defined as CL measuring spectral behavior of the material itself and the receiving characteristics of the human eyes, while measuring the spectral characteristics of lumi-nous efficiency. Through the testing analysis of chosen E-book reader products for experiments, the correlations between different contrasts could be assessed. The experimental results show that under the commonly used light source, the CL and Cv are applicable to assess the relative contrast, taking the light source and the human eye's spectral luminous efficiency characteristics into account, while the CL is more adaptive and applicable to assess the absolute contrast.

  9. Patterns of late embryonic and fetal mortality and association with several factors in sheep.

    Science.gov (United States)

    Dixon, A B; Knights, M; Winkler, J L; Marsh, D J; Pate, J L; Wilson, M E; Dailey, R A; Seidel, G; Inskeep, E K

    2007-05-01

    Embryonic and fetal mortality reduce lambing rates and litter sizes, thus contributing to economic losses in the sheep industry. In the current study, the timing of late embryonic and fetal loss in ewes and the factors with which these losses were associated were examined. Ewes lambing and lambs born were compared with pregnancy diagnosis and counts of embryos by ultrasonography near d 25, 45, 65, or 85 of gestation. Approximately 19.9% of the ewes experienced late embryonic loss, fetal loss, or both; and 21.2% of the embryos or fetuses were lost from d 25 to term. Potential offspring were lost throughout gestation; 3.7% of embryos from d 25 to 45, 4.3% of fetuses from d 45 to 65, 3.3% from d 65 to 85, and 11.5% from d 85 to parturition; thus, approximately 3 to 4% of the potential offspring were lost for each 20-d period of pregnancy beyond d 25. A greater proportion of ewes lost one (36.7%) rather than all (20.5% single; 3.8% multiple) embryos or fetuses. The patterns of loss were similar in ewes mated during the anestrous season and the transitional period and did not vary with service period within breeding season or method of synchronization of estrus. Late embryonic or fetal losses were not related to the temperature-humidity index. Maternal serum collected near d 25, 45, 65, or 85 of gestation was assayed for concentrations of progesterone, estradiol-17beta , and vascular endothelial growth factor (VEGF). The proportions of embryos or fetuses lost were associated with breed type (P < 0.05), as were concentrations of progesterone (P < 0.01), estradiol (P < 0.05), and VEGF (P < 0.01). The relationships of loss or retention of pregnancy to hormonal variables at the 4 stages studied were limited. Complete and partial losses increased rapidly as maternal progesterone at d 25 decreased below 2 ng/mL (P < 0.05). Survival of fetuses within a litter from d 25 to 65 was greater for ewes with medium concentrations of VEGF near d 25 and from d 65 to parturition was

  10. Effects of temperature and sodium carboxylate additives on mineralization of calcium oxalate in silica gel systems

    Institute of Scientific and Technical Information of China (English)

    OUYANG; Jianming; DENG; Suiping; LI; Xiangping; TAN; Yanh

    2004-01-01

    [1]Ouyang, J. M., Yao, X. Q., Su, Z. X. et al., Simulation of calcium oxalate stone in Vitro, Science in China, Ser. B, 2003, 46(3):234-242.[2]Xu, S. H., Chen, J. Q., Zhou, H., Nepidemiological study of renal calculus in Shenshen region, Chin. J. Urol. (in Chinese), 1999,20(11): 655-657.[3]Bretherton, T., Rodgers, A., Crystallization of calcium oxalate in minimally diluted urine, J. Crystal Growth, 1998, 192: 448-455.[4]Grover, P. K., Ryall, R. L., Effect of seed crystals of uric acid and monosodium urate on the crystallization of CaOxa in undiluted human urine in vitro, Clin. Sci., 1997, 92: 205-213.[5]Laube, N., Mohr, B., Hesse, A., Laser-probe-based investigation of the evolution of particle size distributions of calcium oxalate particles formed in artificial urines, J. Crystal Growth, 2001, 233:367-374.[6]Tunik, L., Fueredi-Milhofer, H., Garti, N., Adsorption of sodium diisooctyl sulfosuccinate onto calcium oxalate crystals, Langmuir,1998, 14: 3351-3355.[7]Cody, A. M., Cody, R. D., Calcium oxalate trihydrate phase control by structurally-specific carboxylic acids, J. Cryst. Growth,1994, 135: 234-245.[8]Ouyang, J. M., Duan, L., Tieke, B., Effects of carboxylic acids on the crystal growth of calcium oxalate nanoparticles in lecithin-water liposome systems, Langmuir, 2003, 19: 8980-8985.[9]Guo, S., Ward, M. D., Wesson, J. A., Direct visualization of calcium oxalate monohydrate crystallization and dissolution with atomic force microscopy and the role of polymeric additives,Langmuir, 2002, 18:4284-4291.[10]Yasui, T., Sato, M., Fujita, K., Effects of citrate on renal stone formation and osteopontin expression in a rat urolithiasis model,Urol. Res., 2001,29: 50-56.[11]Ouyang, J. M., Deng, S. P., Controlled and uncontrolled crystallization of calcium oxalate monohydrate in the presence of citric acid, Dalton Transactions, 2003, (14): 2846-2851.[12]Khan, S. R., Whalen, P. O., Glenton, P. A., Heterogeneous nucleation of

  11. Implementing color transformation across media based on color appearance model by neural networks

    Science.gov (United States)

    Chai, Binghua; Liao, Ningfang; Zhao, Dazun

    2005-02-01

    Interest in color appearance models (CAM) has been greatly stimulated recently by the need in handling digital images. This article demonstrates that a multi-layers feed-forward artificial neural network with the error back-propagation algorithm was used to approximate color appearance model CIECAM02 with different white points and different media. For the prediction of the forward and inverse model respectively, in order to realize accurate mapping, especially to the inverse model, color spaces conversion between input color space and output color space (that is cylindrical coordinates and rectangular coordinates) was implemented before training the neural networks. Meanwhile we approximated the combination of the forward and inverse CIECAM02 models employing a neural network for different conditions including whites (D65 or D50) and media (booth and CRT) in order to realize the color transformation from one medium to another conveniently. The experimental results indicated that the prediction could satisfy the accuracy requirement. So in practice we can choose these two kinds of different prediction ways to meet our need according to different situations.

  12. 基于共轭梯度法的纱线染色配方预测优化算法%Dyeing recipes prediction optimization for yarn color matching based on conjugate gradient method

    Institute of Scientific and Technical Information of China (English)

    陈典红; 李海明; 徐新胜

    2011-01-01

    为提高纱线染色配方预测的准确性和稳定性,在Kubelka-Munk理论基础上,结合CIE 1976L*a*b*均匀颜色空间及CIELAB色差公式,提出了以共轭梯度法为基础的染色配方预测优化方法,详细推导出共轭梯度法带约束的配方预测目标函数.利用自开发的测配色软件和美能达CM2600D分光测色仪,选用D65光源,做了大量的单纺纱线测配色实验.实验结果表明,该染料配方预测优化算法计算的配色结果与标准色接近,色差小,与染料配方初值无关,稳定、可靠,收敛性强,重复度高.

  13. Effect of crude saponins from Gaultheria trichophylla extract on growth inhibition in human colorectal cancer cells

    Directory of Open Access Journals (Sweden)

    Fiaz Alam

    2015-03-01

    Full Text Available The genus Gaultheria also comprised of species with reported cytotoxic activities. Current research work was carried out to evaluate G. trichophylla crude extract and respective saponins fraction against human colorectal cancer cell line (Caco-2 based on cell viability assays. Caco-2 cells treated with the crude extract showed significant growth inhibition (p< 0.001 in a dose dependent manner with apparent IC50 value of 200 μg/mL and 100 μg/mL in MTT and NRU assays respectively. The fractioned crude saponins showed an enhanced response and inhibited the growth of Caco-2 by 93.6 and 97.4% in MTT and NRU assays respectively, with compared to actinomycin-D (65%. The DAPI staining of cell treated with crude saponins observed under confocal microscope showed shrunken nuclei with apparent nuclear fragmentation and chromatin condensation indicating apoptosis mode of cell death. The study exhibited that the G. Trichophylla saponins induced apoptosis of Caco-2 cell lines. This study provides new evidences to further explore this plant for the novel targets in anticancer drug development.

  14. 室内白——国际标准新概念%Indoor Whiteness:A New Internationally Standardized Concept

    Institute of Scientific and Technical Information of China (English)

    孙秋菊

    2002-01-01

    @@ 新的ISO标准白度测定要求可在模拟交易大厅的室内环境条件下进行. 最近通过的ISO(国际标准化组织)标准引进了新概念"室内白度".新标准提供了一种在被认为在实际条件下测定纸张白度的新方法.新标准即ISO11476"纸和纸板——CIE白度测定C/2°(室内照明条件)".该标准是对两年前颁布的ISO11475 1999纸和纸板——CIE白度测定D65/10°(室外照明)的补充.当测定含有荧光增白剂纸张时,两种方法规定了在调节仪器紫外线光源的一种常规方法,以便获取再现性.

  15. Characterization of porcine SKIP gene in skeletal muscle development: polymorphisms, association analysis, expression and regulation of cell growth in C2C12 cells.

    Science.gov (United States)

    Xiong, Qi; Chai, Jin; Deng, Changyan; Jiang, Siwen; Liu, Yang; Huang, Tao; Suo, Xiaojun; Zhang, Nian; Li, Xiaofeng; Yang, Qianping; Chen, Mingxin; Zheng, Rong

    2012-12-01

    Skeletal muscle and kidney-enriched inositol phosphatase (SKIP) was identified as a 5'-inositol phosphatase that hydrolyzes phosphatidylinositol (3,4,5)-triphosphate (PI(3,4,5)P3) to PI(3,4)P2 and negatively regulates insulin-induced phosphatidylinositol 3-kinase signaling in skeletal muscle. In this study, two new single nucleotide polymorphisms (SNPs) in porcine SKIP introns 1 and 6 were detected. The C1092T locus in intron 1 showed significant associations with some meat traits, whereas the A17G locus in intron 6 showed significant associations with some carcass traits. Expression analysis showed that porcine SKIP is upregulated at d 65 of gestation and Meishan fetuses have higher and prolonged expression of SKIP compared to Large White at d 100 of gestation. Ectopic expression of porcine SKIP decreased insulin-induced cell proliferation and promoted serum starvation-induced cell cycle arrest in G0/G1 phase in C2C12. Our results suggest that SKIP plays a negative regulatory role in skeletal muscle development partly by preventing cell proliferation.

  16. The importance of chill rate when characterising colour change of lamb meat during retail display.

    Science.gov (United States)

    Jacob, R H; Thomson, K L

    2012-02-01

    An experiment was conducted to compare the effect of two chilling rates (Con and Fast) on colour change of lamb meat during simulated retail display. Measurements were made on 3 muscles; LD (m. longisimuss dorsi), SM (m semimembranosus) and ST (m. semitendinous). Meat samples from 32 Merino crossbred lambs were vacuum packed and stored for 5 days at 2 °C, then cut and overwrapped in polyvinyl chloride film on black polystyrene trays, stored in a display cabinet at 4 °C with lights on and measured twice daily for 4 days, using a Hunterlab minilab 45/20L D65, aperture 10°. Sarcomere length was shorter, shear force higher and colour change greater in meat from the Fast treatment compared to the Con treatment. Colour differences between treatments were likely due to oxygenation (bloom) as well as oxidation effects. Chill rate is important when characterising colour change during display and should be considered in measurement protocols. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. The Impact of Variation in Foliar Constituents of Sunflower on Development and Reproduction of Diacrisia casignetum Kollar (Lepidoptera: Arctiidae

    Directory of Open Access Journals (Sweden)

    Nayan Roy

    2012-01-01

    Full Text Available Effects of feeding on young, mature, and senescent sunflower leaves were studied under laboratory conditions (27 ± 0.5°C, 12L : 12D, 65±5% RH to evaluate the impact of variation of nutrients on larval food utilization efficiency, larval and pupal development and survival, longevity, and fecundity of Diacrisia casignetum Kollar. The growth rate, which is the ratio between the dry weight gain of insect and duration of experimental period, of D. casignetum was in the order of mature leaf > young leaf > senescent leaf of sunflower. This was correlated with nutrient constituents of three kinds of sunflower leaves, which was measured by various biochemical analyses described elsewhere in the text. Total carbohydrates, proteins, lipids, nitrogen, amino acids, and water content are in greater amount in mature leaves when compared to young and senescent leaves, whereas phenol content was highest in young leaves than mature leaves. Hence, higher amount of total carbohydrates, proteins, lipids, nitrogen, amino acids including water and lower amount of total phenol content in mature leaves have influenced higher growth rate, less developmental time, and higher fecundity of D. casignetum.

  18. Is discrimination enhanced at the boundaries of perceptual categories? A negative case.

    Science.gov (United States)

    Danilova, M V; Mollon, J D

    2014-06-22

    The human visual system imposes discrete perceptual categories on the continuous input space that is represented by the ratios of excitations of the cones in the retina. Is discrimination enhanced at the boundaries between perceptual hues, in the way that discrimination may be enhanced at the boundaries between speech sounds in hearing? In the chromaticity diagram, the locus of unique green separates colours that appear yellowish from those that appear bluish. Using a two-alternative spatial forced choice and an adapting field equivalent to the Daylight Illuminant D65, we measured chromatic discrimination along lines orthogonal to the locus of unique green. In experimental runs interleaved with these performance measurements, we obtained estimates of the phenomenological boundary from the same observers. No enhancement of objectively measured discrimination was observed at the category boundary between yellowish and bluish hues. Instead, thresholds were minimal at chromaticities where the ratio of long-wave to middle-wave cone excitation was the same as that for the background adapting field.

  19. Usability of Calibrating Monitor for Soft Proof According to CIE CAM02 Colour Appearance Model

    Directory of Open Access Journals (Sweden)

    Dragoljub Novakovic

    2010-06-01

    Full Text Available Colour appearance models describe viewing conditions and enable simulating appearance of colours under different illuminants and illumination levels according to human perception. Since it is possible to predict how colour would look like when different illuminants are used, colour appearance models are incorporated in some monitor profiling software. Owing to these software, tone reproduction curve can be defined by taking into consideration viewing condition in which display is observed. In this work assessment of CIE CAM02 colour appearance model usage at calibrating LCD monitor for soft proof was tested in order to determine which tone reproduction curve enables better reproduction of colour. Luminance level was kept constant, whereas tone reproduction curves determined by gamma values and by parameters of CIE CAM02 model were varied. Testing was conducted in case where physical print reference is observed under illuminant which has colour temperature according to iso standard for soft-proofing (D50 and also for illuminants D65.  Based on the results of calibrations assessment, subjective and objective assessment of created profiles, as well as on the perceptual test carried out on human observers, differences in image display were defined and conclusions of the adequacy of CAM02 usage at monitor calibration for each of the viewing conditions reached.

  20. Interaction between staining and degradation of a composite resin in contact with colored foods

    Directory of Open Access Journals (Sweden)

    Debora Soares-Geraldo

    2011-08-01

    Full Text Available Composite resins might be susceptible to degradation and staining when in contact with some foods and drinks. This study evaluated color alteration and changes in microhardness of a microhybrid composite after immersion in different colored foods and determined whether there was a correlation between these two variables. Eighty composite disks were randomly divided into 8 experimental groups (n = 10: kept dry; deionized water; orange juice; passion fruit juice; grape juice; ketchup; mustard and soy sauce. The disks were individually immersed in their respective test substance at 37 ºC, for a period of 28 days. Superficial analysis of the disk specimens was performed by taking microhardness measurements (Vickers, 50 g load for 45 seconds and color alterations were determined with a spectrophotometer (CINTRA 10- using a CIEL*a*b* system, 400-700 nm wavelength, illuminant d65 and standard observer of 2º at the following times: baseline (before immersion, 1, 7, 14, 21 and 28 days. Results were analyzed by ANOVA and Tukey's test (p < 0.05. Both variables were also submitted to Pearson's correlation test (p < 0.05. The passion fruit group underwent the greatest microhardness change, while the mustard group suffered the greatest color alteration. Significant positive correlation was found between the two variables for the groups deionized water, grape juice, soy sauce and ketchup. Not all color alteration could be associated with surface degradation.

  1. An eco-friendly dyeing of woolen yarn by Terminalia chebula extract with evaluations of kinetic and adsorption characteristics

    Science.gov (United States)

    Shabbir, Mohd; Rather, Luqman Jameel; Shahid-ul-Islam; Bukhari, Mohd Nadeem; Shahid, Mohd; Ali Khan, Mohd; Mohammad, Faqeer

    2016-01-01

    In the present study Terminalia chebula was used as an eco-friendly natural colorant for sustainable textile coloration of woolen yarn with primary emphasis on thermodynamic and kinetic adsorption aspects of dyeing processes. Polyphenols and ellagitannins are the main coloring components of the dye extract. Assessment of the effect of pH on dye adsorption showed an increase in adsorption capacity with decreasing pH. Effect of temperature on dye adsorption showed 80 °C as optimum temperature for wool dyeing with T. chebula dye extract. Two kinetic equations, namely pseudo first-order and pseudo second-order equations, were employed to investigate the adsorption rates. Pseudo second-order model provided the best fit (R2 = 0.9908) to the experimental data. The equilibrium adsorption data were fitted by Freundlich and Langmuir isotherm models. The adsorption behavior accorded well (R2 = 0.9937) with Langmuir isotherm model. Variety of eco-friendly and sustainable shades were developed in combination with small amount of metallic mordants and assessed in terms of colorimetric (CIEL∗a∗b∗ and K/S) properties measured using spectrophotometer under D65 illuminant (10° standard observer). The fastness properties of dyed woolen yarn against light, washing, dry and wet rubbing were also evaluated. PMID:27222752

  2. Moderate exercise, postprandial energy expenditure, and substrate use in varying meals in lean and obese men.

    Science.gov (United States)

    Stiegler, Petra; Sparks, S Andrew; Cunliffe, Adam

    2008-02-01

    Maximizing postprandial energy expenditure and fat oxidation could be of clinical relevance for the treatment of obesity. This study investigated the effect of prior exercise on energy expenditure and substrate utilization after meals containing varying amounts of macronutrients. Eight lean (11.6%+/-4.0% body fat, M+/-SD) and 12 obese (35.9%+/-5.3% body fat) men were randomly assigned to a protein (43% protein, 30% carbohydrate) or a carbohydrate (10% protein, 63% carbohydrate) meal. The metabolic responses to the meals were investigated during 2 trials, when meals were ingested after a resting period (D) or cycling exercise (Ex+D; 65% of oxygen consumption reserve, 200 kcal). Energy expenditure, substrate utilization, and glucose and insulin responses were measured for 4 hr during the postprandial phase. Although postprandial energy expenditure was not affected by prior exercise, the total amount of fat oxidized was higher during Ex+D than during D (170.8+/-60.1 g vs. 137.8+/-50.8 g, pexercise. Plasma insulin tended to be lower during Ex+D (p= .072) and after the protein meal (p= .066). No statistically significant change in postprandial blood glucose was induced by prior exercise. Exercising before meal consumption can result in a marked increase in fat oxidation, which is independent of the type of meal consumed.

  3. Lack of homozygotes for the most frequent disease allele in carbohydrate-deficient glycoprotein syndrome type 1A.

    Science.gov (United States)

    Matthijs, G; Schollen, E; Van Schaftingen, E; Cassiman, J J; Jaeken, J

    1998-03-01

    Carbohydrate-deficient-glycoprotein syndrome type 1 (CDG1; also known as "Jaeken syndrome") is an autosomal recessive disorder characterized by defective glycosylation. Most patients show a deficiency of phosphomannomutase (PMM), the enzyme that converts mannose 6-phosphate to mannose 1-phosphate in the synthesis of GDP-mannose. The disease is linked to chromosome 16p13, and mutations have recently been identified in the PMM2 gene in CDG1 patients with a PMM deficiency (CDG1A). The availability of the genomic sequences of PMM2 allowed us to screen for mutations in 56 CDG1 patients from different geographic origins. By SSCP analysis and by sequencing, we identified 23 different missense mutations and 1 single-base-pair deletion. In total, mutations were found on 99% of the disease chromosomes in CDG1A patients. The R141H substitution is present on 43 of the 112 disease alleles. However, this mutation was never observed in the homozygous state, suggesting that homozygosity for these alterations is incompatible with life. On the other hand, patients were found homozygous for the D65Y and F119L mutations, which must therefore be mild mutations. One particular genotype, R141H/D188G, which is prevalent in Belgium and the Netherlands, is associated with a severe phenotype and a high mortality. Apart from this, there is only a limited relation between the genotype and the clinical phenotype.

  4. Therapist-assisted Internet-delivered cognitive behavior therapy for depression and anxiety: translating evidence into clinical practice.

    Science.gov (United States)

    Hadjistavropoulos, H D; Pugh, N E; Nugent, M M; Hesser, H; Andersson, G; Ivanov, M; Butz, C G; Marchildon, G; Asmundson, G J G; Klein, B; Austin, D W

    2014-12-01

    This dissemination study examined the effectiveness of therapist-assisted Internet-delivered Cognitive Behavior Therapy (ICBT) when offered in clinical practice. A centralized unit screened and coordinated ICBT delivered by newly trained therapists working in six geographically dispersed clinical settings. Using an open trial design, 221 patients were offered 12 modules of ICBT for symptoms of generalized anxiety (n=112), depression (n=83), or panic (n=26). At baseline, midpoint and post-treatment, patients completed self-report measures. On average, patients completed 8 of 12 modules. Latent growth curve modeling identified significant reductions in depression, anxiety, stress and impairment (d=.65-.78), and improvements in quality of life (d=.48-.66). Improvements in primary symptoms were large (d=.91-1.25). Overall, therapist-assisted ICBT was effective when coordinated across settings in clinical practice, but further attention should be given to strategies to improve completion of treatment modules. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. Validation Protocol of Vitamin D Supplementation in Patients with HIV-Infection

    Science.gov (United States)

    Güerri-Fernández, Roberto; Villar García, Judit; González Mena, Alicia; Guelar Grinberg, Ana; Montero, María Milagro; Sorli, Luisa; Calzado, Sonia; Horcajada, Juan Pablo; Díez-Pérez, Adolfo; Knobel Freud, Hernando

    2016-01-01

    Hypovitaminosis D and secondary hyperparathyroidism are frequent among HIV-infected patients. As there are no data about the best supplementation therapy both in treatment and in maintenance, we conducted an observational study of 300 HIV-infected patients for whom vitamin D and parathormone (PTH) had been measured in order to validate a protocol of vitamin D supplementation in patients with HIV-infection. Patients with vitamin D deficiency (defined as 25(OH)D 65 pg/mL) were supplemented with cholecalciferol 16.000IU (0.266 mg) weekly (if deficiency) or fortnightly (if insufficiency or high PTH levels). Rates of normalization of 25(OH)D (levels above 20 ng/mL) and PTH levels (<65 pg/mL) were analyzed. Multivariate analysis of factors related to normalization was carried out. With a median follow-up of 2 years, 82.1% of patients with deficiency and 83.9% of cases with insufficiency reached levels above 20 ng/mL. However, only 67.2% of individuals with hyperparathyroidism at baseline reached target levels (<65 pg/mL). Independent factors for not achieving PTH objective were tenofovir (TDF) and protease inhibitors use. In HIV-infected patients with hypovitaminosis, the protocol of cholecalciferol supplementation normalized vitamin D levels regardless of antiretroviral regimen in a high proportion of patients but it was less effective to correct hyperparathyroidism. PMID:27699068

  6. Effect of Brushing Time and Dentifrice Abrasiveness on Color Change and Surface Roughness of Resin Composites.

    Science.gov (United States)

    Roselino, Lourenço de Moraes Rego; Chinelatti, Michelle Alexandra; Alandia-Román, Carla Cecilia; Pires-de-Souza, Fernanda de Carvalho Panzeri

    2015-10-01

    Dentifrice abrasiveness and brushing time may increase color change (∆E) and surface roughness (∆Ra) of resin composites. This study aimed to evaluate the effect of mechanical brushing time of dentifrices with different abrasiveness on ∆E and ∆Ra of nanofilled (Z350, 3M ESPE) and nanohybrid (Tetric N-Ceram, Ivoclar Vivadent) resin composites. Sixteen specimens (12 mm diameter x 2 mm thick) were fabricated using a white Teflon matrix of each resin composite and a ceramic (IPS e.max Ceram, Ivoclar Vivadent), used as control. After initial color readouts on white backgrounds (Spectrophotometer PCB 6807, Byk Gardner), with D65 standard illuminant, and surface roughness (Rugosimeter Surfcorder SE 1700, Kosalab) with cut-off=0.8 mm and speed=0.25 mm/s, specimens were assigned (n=8) according to the abrasiveness of the dentifrices: RDA* 68 (Colgate) and RDA* 180 (Colgate Total Plus Whitening). Specimens were submitted to mechanical brushing (58,400 cycles) and after every 14,600 cycles (1 year of brushing by a healthy individual), new color and surface roughness readouts were taken. Color stability was calculated by CIEDE2000. Data were analyzed by 3-way repeated measures ANOVA and Bonferroni test (pdentifrice abrasiveness (p=0.02) and brushing time (pdentifrice abrasiveness, the greater the color change of the nanofilled resin composite. The surface roughness was not influenced by dentifrice abrasiveness.

  7. An eco-friendly dyeing of woolen yarn by Terminalia chebula extract with evaluations of kinetic and adsorption characteristics.

    Science.gov (United States)

    Shabbir, Mohd; Rather, Luqman Jameel; Shahid-Ul-Islam; Bukhari, Mohd Nadeem; Shahid, Mohd; Ali Khan, Mohd; Mohammad, Faqeer

    2016-05-01

    In the present study Terminalia chebula was used as an eco-friendly natural colorant for sustainable textile coloration of woolen yarn with primary emphasis on thermodynamic and kinetic adsorption aspects of dyeing processes. Polyphenols and ellagitannins are the main coloring components of the dye extract. Assessment of the effect of pH on dye adsorption showed an increase in adsorption capacity with decreasing pH. Effect of temperature on dye adsorption showed 80 °C as optimum temperature for wool dyeing with T. chebula dye extract. Two kinetic equations, namely pseudo first-order and pseudo second-order equations, were employed to investigate the adsorption rates. Pseudo second-order model provided the best fit (R (2) = 0.9908) to the experimental data. The equilibrium adsorption data were fitted by Freundlich and Langmuir isotherm models. The adsorption behavior accorded well (R (2) = 0.9937) with Langmuir isotherm model. Variety of eco-friendly and sustainable shades were developed in combination with small amount of metallic mordants and assessed in terms of colorimetric (CIEL(∗) a (∗) b (∗) and K/S) properties measured using spectrophotometer under D65 illuminant (10° standard observer). The fastness properties of dyed woolen yarn against light, washing, dry and wet rubbing were also evaluated.

  8. NEUROPSI battery subtest profile in subcortical vascular dementia and Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Maria Niures P.S. Matioli

    Full Text Available ABSTRACT Objective: To investigate the diagnostic value of subtests of the NEUROPSI battery for differentiating subcortical vascular dementia (SVaD from Alzheimer's disease (AD. Methods: Thirteen patients with mild SVaD, 15 patients with mild probable AD, and 30 healthy controls, matched for age, education and dementia severity (in the case of patients, were submitted to the Mini-Mental State Examination (MMSE and NEUROPSI battery. The performance of AD and SVaD groups on NEUROPSI subtests was compared. The statistical analyses were performed using Kruskal-Wallis, Chi-square and Mann-Whitney tests. The results were interpreted at the 5% significance level (p<0.05. Bonferroni's correction was applied to multiple comparisons (a=0.02. Results: SVaD and AD patients showed no statistical difference in MMSE scores (SVaD=20.8 and AD=21.0; p=1.0 or in NEUROPSI total score (SVaD=65.0 and AD=64.3; p=0.56, suggesting a similar severity of dementia. The AD group performed worse on memory recall (<0.01 and SVaD group was worse in verbal fluency subtests (p=0.02. Conclusion: NEUROPSI's memory and language subtests can be an auxiliary tool for differentiating SVaD from AD.

  9. Refined live attenuated Salmonella enterica serovar Typhimurium and Enteritidis vaccines mediate homologous and heterologous serogroup protection in mice.

    Science.gov (United States)

    Tennant, Sharon M; Schmidlein, Patrick; Simon, Raphael; Pasetti, Marcela F; Galen, James E; Levine, Myron M

    2015-12-01

    Invasive nontyphoidal Salmonella (NTS) infections constitute a major health problem among infants and toddlers in sub-Saharan Africa; these infections also occur in infants and the elderly in developed countries. We genetically engineered a Salmonella enterica serovar Typhimurium strain of multilocus sequence type 313, the predominant genotype circulating in sub-Saharan Africa. We evaluated the capacities of S. Typhimurium and Salmonella enterica serovar Enteritidis ΔguaBA ΔclpX live oral vaccines to protect mice against a highly lethal challenge dose of the homologous serovar and determined protection against other group B and D serovars circulating in sub-Saharan Africa. The vaccines S. Typhimurium CVD 1931 and S. Enteritidis CVD 1944 were immunogenic and protected BALB/c mice against 10,000 50% lethal doses (LD50) of S. Typhimurium or S. Enteritidis, respectively. S. Typhimurium CVD 1931 protected mice against the group B serovar Salmonella enterica serovar Stanleyville (91% vaccine efficacy), and S. Enteritidis CVD 1944 protected mice against the group D serovar Salmonella enterica serovar Dublin (85% vaccine efficacy). High rates of survival were observed when mice were infected 12 weeks postimmunization, indicating that the vaccines elicited long-lived protective immunity. Whereas CVD 1931 did not protect against S. Enteritidis R11, CVD 1944 did mediate protection against S. Typhimurium D65 (81% efficacy). These findings suggest that a bivalent (S. Typhimurium and S. Enteritidis) vaccine would provide broad protection against the majority of invasive NTS infections in sub-Saharan Africa.

  10. Film with anthocyanins as an indicator of chilled pork deterioration

    Directory of Open Access Journals (Sweden)

    Luana Baptista Golasz

    2013-02-01

    Full Text Available An indicator can be defined as a substance which indicates the presence or absence of another substance or the degree of a certain reaction through characteristic changes, especially color. Therefore, the aim of this work is to evaluate the performance of a bio-based film with anthocyanin as an indicator of chilled pork deterioration. A film made of cassava starch, glycerol, and grape anthocyanins was prepared using the casting technique. Pork loin samples were put in Petri dishes containing an anthocyanin film on the bottom and stored at 4 ºC. Psychrotrophic microorganism count and the pH of the pork loin samples were analyzed for a 14 day- period. At the same time, the films were subjected to colorimetric analysis using D65 illuminant and the CIELAB system. Chroma and hue angle data for these films were evaluated by Anova and Dunnett's test. An increase in the microbial population and in the pH was observed over the storage period as result of pork deterioration. Color changes were also identified in the film. However, only at the beginning of the storage period was it possible to establish a correlation between film color and pork deterioration. The shelf life end-point could not be clearly detected by the film.

  11. Analysis of the influence of the aperture size on the differences of L *a *b chromatic coordinates in a spectrocolorimeter

    Science.gov (United States)

    Medina-Marquez, J.; Balderas-Mata, S. E.; Flores, Jorge L.

    2016-09-01

    The study of the influence of the aperture size over the measurements of the L*a*b chromatic coordinates in spectrocolorimeters, in particular, the Macbeth 7000A ® spectrocolorimeter with an illumination/detection geometry d/8°. This is of importance due to the fact that many industry laboratories use it. This study will give us an invaluable insight of the variations in the measurements of the chromatic coordinates in the visible spectrum range regarding to three different aperture sizes; 2,5cm (AL), 1cm (AM), and 0,5cm (AS). The measurements are carried out on 13 Reference Materials (RMs) or diffusers with different hue under the following metrics; including specular component (SCI), excluding ultraviolet component (UVex), D65 illuminant, and 2° observer. The analysis and quantification of the data were done by the use of statistical tools such as variance analysis and Mendel parameters. In this work the analysis of the latter measurements as well as the methodology that quantifies the accuracy and precision of the method, i.e., repeatability and reproducibility, are presented.

  12. INFLUENCE OF MILK FAT IN THE RESISTANCE OF Mycobacterium fortuitum TO SLOW PASTEURIZATION

    Directory of Open Access Journals (Sweden)

    Karina Ramirez Starikoff

    2016-01-01

    Full Text Available ortuitum. Milk samples were divided into two portions, whole and skimmed, each part was inoculated with M. fortuitum and then distributed in tubes for quantification of the agent during pasteurization, in a water bath. As samples were diluted and plated on Lowenstein-Jensen (37 °C/5 days, the count results were expressed as log10 CFU/mL. The heat treatment reduced 4.4 log10 CFU/mL for goat whole milk (2.8% fat, 4.9 log10 CFU/mL for skim goat milk (0.3%, 3.9 log10 CFU/ml for whole bovine milk (5.9%, and 5.4 log10 CFU/mL for skim bovine milk (0.2%, without significant difference, possibly because of the low number of samples. Values of D65 °C were, respectively, 10.51 minutes, 8.61 minutes, 18.02 minutes, and 7.82 minutes and the low R2 value of the straight line equations indicated that other factors, in addition to the ones studied, influenced the heat death of the agent. The results suggest a trend of influence by fat milk, and by the animal species on the decay rate of M. fortuitum, and that pasteurization was less effective over M. fortuitum in whole bovine milk. Keywords: fat content;

  13. Domain Modeling: NP_777557.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available hr20/NP_777557.1/NP_777557.1_holo_16-453.pdb psi-blast 22A,24L,26L,31M,32N,34V,35Q,38M,39D,65T,66N,79L,87I,8...9Q,101S,103M,106N,119N,121L,123R,125E,130P,132F,177I,181L,184V,185N,187K,188W,189T,191L,192S,195M,196P,197V,198G,205Y,207L,...208M,209S,210A,218I,220L,222F,253S,255Q,257L,261T,262F,265A,266E,269L,...272K,273S,274F,275H,276V,283I,286L,287P,311L,313T,315I,316K,317I,321P,323V,330S,332L,334L,336S,338L,360F,362L,...364V,365Q,366Y,368V,373L,375M,377T,391S,392I,393G,394N,396N,397E,398R,401T,407Y,408L,411A,412Y,413I,416V,417N,419V,420L,424L,

  14. Number of discernible colors for color-deficient observers estimated from the MacAdam limits.

    Science.gov (United States)

    Perales, Esther; Martínez-Verdú, Francisco Miguel; Linhares, João Manuel Maciel; Nascimento, Sérgio Miguel Cardoso

    2010-10-01

    We estimated the number of colors perceived by color normal and color-deficient observers when looking at the theoretic limits of object-color stimuli. These limits, the optimal color stimuli, were computed for a color normal observer and CIE standard illuminant D65, and the resultant colors were expressed in the CIELAB and DIN99d color spaces. The corresponding color volumes for abnormal color vision were computed using models simulating for normal trichromatic observers the appearance for dichromats and anomalous trichomats. The number of colors perceived in each case was then computed from the color volumes enclosed by the optimal colors also known as MacAdam limits. It was estimated that dichromats perceive less than 1% of the colors perceived by normal trichromats and that anomalous trichromats perceive 50%-60% for anomalies in the medium-wavelength-sensitive and 60%-70% for anomalies in the long-wavelength-sensitive cones. Complementary estimates obtained similarly for the spectral locus of monochromatic stimuli suggest less impairment for color-deficient observers, a fact that is explained by the two-dimensional nature of the locus.

  15. Influence of surface roughness on the color of dental-resin composites

    Institute of Scientific and Technical Information of China (English)

    Razvan GHINEA; Laura UGARTE-ALVAN; Ana YEBRA; Oscar E. PECHO; Rade D. PARAVINA; Maria del Mar PEREZ

    2011-01-01

    This study deals with the influence of surface roughness on the color of resin composites.Ten resin composites (microfilled,hybrid,and microhybrid) were each polished with 500-grit,1200-grit,2000-grit,and 4000-grit SiC papers.The roughness parameter (Ra) was measured using a Plμ confocal microscope,and field-emission scanning electron microscope (Fe-SEM) images were used to investigate filler morphology.Color was measured using a spectroradiometer and a D65 standard illuminant (geometry diffuse/0° specular component excluded (SCE) mode).Surface roughness decreased,with grit number and was not influenced by filler size or size distribution.A significant influence of Ra on lightness (L) was found.Lightness increased with decreases in roughness,except for specimens that underwent polishing procedure 4 (PP4; 500-grit,1200-grit,2000-grit,and 4000-grit SiC papers consecutively).Generally,it was found that surface roughness influenced the color of resin composites.The composites that underwent PP1 (500-grit SiC paper) exhibited significant differences in chroma (C),hue (h°),and lightness (L*) compared to composites that underwent PP3 (500-grit,1200-grit,and 2000-grit SiC papers consecutively) and PP4.Color difference (△E*) between the polishing procedures was within acceptability thresholds in dentistry.

  16. Optimization of Multiband White-Light Illuminants for Specified Color Temperatures

    Directory of Open Access Journals (Sweden)

    Snjezana Soltic

    2015-01-01

    Full Text Available This paper describes an effective approach for the optimization of multiband spectra to produce prospective white-light spectra having specific color temperatures. The optimization process employs a genetic algorithm known as differential evolution, which aims to minimize the color rendering differences between a prospective white-light spectrum and its corresponding reference illuminant. Color rendering is assessed by calculating the CIEDE2000 color difference (ΔE00 for 14 CIE test colors under the two sources. Optimized white-light spectra were matched to three CIE standard illuminants, that is, A (2856 K, D50 (5003 K, and D65 (6504 K. Optimal solutions for three- and four-band 25 and 50 nm Gaussian spectra are presented and analyzed, together with mixed 4-LED spectra that were optimized in the same way. In all cases, the simulated sources were shown to provide color rendering of such quality that ΔE00av ≤ 2.24 units. Such white-light sources would likely find wide acceptance in numerous lighting applications.

  17. Visual optics: an engineering approach

    Science.gov (United States)

    Toadere, Florin

    2010-11-01

    The human eyes' visual system interprets the information from the visible light in order to build a representation of the world surrounding the body. It derives color by comparing the responses to light from the three types of photoreceptor cones in the eyes. These long medium and short cones are sensitive to blue, green and red portions of the visible spectrum. We simulate the color vision for the normal eyes. We see the effects of the dyes, filters, glasses and windows on color perception when the test image is illuminated with the D65 light sources. In addition to colors' perception, the human eyes can suffer from diseases and disorders. The eye can be seen as an optical instrument which has its own eye print. We present aspects of some nowadays methods and technologies which can capture and correct the human eyes' wavefront aberrations. We focus our attention to Siedel aberrations formula, Zenike polynomials, Shack-Hartmann Sensor, LASIK, interferograms fringes aberrations and Talbot effect.

  18. Kinetic mechanism of phenylalanine hydroxylase: intrinsic binding and rate constants from single-turnover experiments.

    Science.gov (United States)

    Roberts, Kenneth M; Pavon, Jorge Alex; Fitzpatrick, Paul F

    2013-02-12

    Phenylalanine hydroxylase (PheH) catalyzes the key step in the catabolism of dietary phenylalanine, its hydroxylation to tyrosine using tetrahydrobiopterin (BH(4)) and O(2). A complete kinetic mechanism for PheH was determined by global analysis of single-turnover data in the reaction of PheHΔ117, a truncated form of the enzyme lacking the N-terminal regulatory domain. Formation of the productive PheHΔ117-BH(4)-phenylalanine complex begins with the rapid binding of BH(4) (K(d) = 65 μM). Subsequent addition of phenylalanine to the binary complex to form the productive ternary complex (K(d) = 130 μM) is approximately 10-fold slower. Both substrates can also bind to the free enzyme to form inhibitory binary complexes. O(2) rapidly binds to the productive ternary complex; this is followed by formation of an unidentified intermediate, which can be detected as a decrease in absorbance at 340 nm, with a rate constant of 140 s(-1). Formation of the 4a-hydroxypterin and Fe(IV)O intermediates is 10-fold slower and is followed by the rapid hydroxylation of the amino acid. Product release is the rate-determining step and largely determines k(cat). Similar reactions using 6-methyltetrahydropterin indicate a preference for the physiological pterin during hydroxylation.

  19. Water withdrawals in Florida, 2012

    Science.gov (United States)

    Marella, Richard L.

    2015-09-01

    In 2012, the total amount of water withdrawn in Florida was estimated to be 14,237 million gallons per day (Mgal/d). Saline water accounted for 7,855 Mgal/d (55 percent), and freshwater accounted for 6,383 Mgal/d (45 percent). Groundwater accounted for 4,167 Mgal/d (65 percent) of freshwater withdrawals, and surface water accounted for the remaining 2,216 Mgal/d (35 percent). Surface water accounted for nearly all (99.9 percent) saline-water withdrawals. Freshwater withdrawals were greatest in Palm Beach County (682 Mgal/d), and saline-water withdrawals were greatest in Pasco County (1,822 Mgal/d). Fresh groundwater provided drinking water (through either public supply or private domestic wells) for 17.699 million residents (93 percent of Florida’s population), and fresh surface water provided drinking water for 1.375 million residents (7 percent). The statewide public-supply gross per capita water use for 2012 was estimated at 136 gallons per day.

  20. Optimal estimation of spectral reflectance based on metamerism

    Science.gov (United States)

    Chou, Tzren-Ru; Lin, Wei-Ju

    2012-01-01

    In this paper, we proposed an accurate estimation method for spectral reflectance of objects captured in an image. The spectral reflectance is simply modeled by a linear combination of three basic spectrums of R, G, and B colors respectively, named as spectral reflective bases of objects, which are acquired by solving a linear system based on the principle of color metamerism. Some experiments were performed to evaluate the accuracy of the estimated spectral reflectance of objects. The average mean square error of 24 colors in Macbeth checker between we simulated and the measured is 0.0866, and the maximum is 0.310. In addition, the average color difference of the 24 colors is less than 1.5 under the D65 illuminant. There are 13 colors having their color difference values less than 1, and other 8 colors having the values during the range of 1 and 2. Only three colors are relatively larger, with the differences of 2.558, 4.130 and 2.569, from the colors of No. 2, No. 13, and No. 18 in Macbeth checker respectively. Furthermore, the computational cost of this spectral estimation is very low and suitable for many practical applications in real time.

  1. Effects of Display Gamma and Illuminant on the Appearance of Colours Viewed on LCD Monitors

    Directory of Open Access Journals (Sweden)

    Dragoljub Novakovic

    2009-11-01

    Full Text Available The CIECAM02 colour appearance model was developed to allow prediction of accurate colour appearance under various viewing conditions. In this study, a software module, based on mathematical transformations of the CIECAM02 model, was designed and implemented. Unlike the previous software modules, which were allowing use of only a limited choice of common standardized icc display profiles, the developed module also allows the use of optimized profiles created by the user. This paper presents prediction of the appearance of test images with assigned different display profiles after changing illuminant. The two used optimized profiles, created by software characterization of specific lcd display, have a different display gamma value (1.8 and 2.2.  It is observed that, after changing the initial cie D50 to a higher colour temperature illuminant (D65,  the colours of  images will be shifted to the blue hues, and, in the case of illuminant temperature less than D50 (A and F11,  to yellow hues. It is also observed that the intensity of colour shifts in the simulated images with associated profiles which have different gamma value will be significantly different, which implies that the icc display profile and display gamma value have the great impact on the prediction of the accurate colour appearance under various viewing conditions.

  2. Usability of Calibrating Monitor for Soft Proof According to cie cam02 Colour Appearance Model

    Directory of Open Access Journals (Sweden)

    Ivana Tomić

    2010-01-01

    Full Text Available Colour appearance models describe viewing conditions and enable simulating appearance of colours under different illuminants and illumination levels according to human perception. Since it is possible to predict how colour would look like when different illuminants are used, colour appearance models are incorporated in some monitor profiling software. Owing to these software, tone reproduction curve can be defined by taking into consideration viewing condition in which display is observed. In this work assessment of cie cam02 colour appearance model usage at calibrating lcd monitor for soft proof was tested in order to determine which tone reproduction curve enables better reproduction of colour. Luminance level was kept constant, whereas tone reproduction curves determined by gamma values and by parameters of cie cam02 model were varied. Testing was conducted in case where physical print reference is observed under illuminant which has colour temperature according to iso standard for soft-proofing (d50 and also for illuminants d65. Based on the results of calibrations assessment, subjective and objective assessment of created profiles, as well as on the perceptual test carried out on human observers, differences in image display were defined and conclusions of the adequacy of cam02 usage at monitor calibration for each of the viewing conditions reached.

  3. Effects Of Display Gamma And Illuminant On The Appearance Of Colours Viewed On Lcd Monitors

    Directory of Open Access Journals (Sweden)

    Neda Milić

    2009-01-01

    Full Text Available The ciecam02 colour appearance model was developed to allow prediction of accurate colour appearance under various viewing conditions. In this study, a software module, based on mathematical transformations of the ciecam02 model, was designed and implemented. Unlike the previous software modules, which were allowing use of only a limited choice of common standardized icc display profiles, the developed module also allows the use of optimized profiles created by the user. This paper presents prediction of the appearance of test images with assigned different display profiles after changing illuminant. The two used optimized profiles, created by software characterization of specific lcd display, have a different display gamma value (1.8 and 2.2. It is observed that, after changing the initial cie d50 to a higher colour temperature illuminant (d65, the colours of images will be shifted to the blue hues, and, in the case of illuminant temperature less than d50 (a and f11, to yellow hues. It is also observed that the intensity of colour shifts in the simulated images with associated profiles which have different gamma value will be significantly different, which implies that the icc display profile and display gamma value have the great impact on the prediction of the accurate colour appearance under various viewing conditions.

  4. Colapso gravitacional radiativo esféricamente simétrico en relatividad general: introducción del factor de flujo, el factor de Eddington y la influencia de la relación de clausura entre ellos sobre la evolución del sistema

    Directory of Open Access Journals (Sweden)

    A. A. Navarro L.

    2007-01-01

    Full Text Available Se extiende el método H–J–R [ Phys. Rev. D22, 2305 (1980] uti- lizando el factor variable de Eddington y el factor de flujo de radiación, y se presenta la influencia de la elección de la relación entre ellos sobre el comportamiento en el tiempo de la densidad, presión, veloci dad del fluido y flujo de radiación, entre otras, de un objeto en fase de colaps o gravitacional radiativo en el marco de la relatividad general. Para tal fin, se ha utilizado la aproximación poscuasiestática de Herrera et al [ Phys. Rev. D65, 104004 (2002] con la ecuación de estado Tolman VI y las relaciones d e clausura de Lorentz–Eddington, Bowers–Wilson y Maximum Packing, en contrando que la elección de una relación de clausura particular no afe cta el compor- tamiento general del colapso, pero sí afecta los valores ins tantáneos de las diferentes magnitudes físicas.

  5. Persistent topological features of dynamical systems

    Energy Technology Data Exchange (ETDEWEB)

    Maletić, Slobodan, E-mail: slobodan@hitsz.edu.cn [Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen (China); Institute of Nuclear Sciences Vinča, University of Belgrade, Belgrade (Serbia); Zhao, Yi, E-mail: zhao.yi@hitsz.edu.cn [Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen (China); Rajković, Milan, E-mail: milanr@vinca.rs [Institute of Nuclear Sciences Vinča, University of Belgrade, Belgrade (Serbia)

    2016-05-15

    Inspired by an early work of Muldoon et al., Physica D 65, 1–16 (1993), we present a general method for constructing simplicial complex from observed time series of dynamical systems based on the delay coordinate reconstruction procedure. The obtained simplicial complex preserves all pertinent topological features of the reconstructed phase space, and it may be analyzed from topological, combinatorial, and algebraic aspects. In focus of this study is the computation of homology of the invariant set of some well known dynamical systems that display chaotic behavior. Persistent homology of simplicial complex and its relationship with the embedding dimensions are examined by studying the lifetime of topological features and topological noise. The consistency of topological properties for different dynamic regimes and embedding dimensions is examined. The obtained results shed new light on the topological properties of the reconstructed phase space and open up new possibilities for application of advanced topological methods. The method presented here may be used as a generic method for constructing simplicial complex from a scalar time series that has a number of advantages compared to the mapping of the same time series to a complex network.

  6. Measurement of the spectral characteristics and color parameters of flat objects

    Science.gov (United States)

    Gorbunova, Elena V.; Chertov, Aleksandr N.; Lastovskaia, Elena A.; Korotaev, Valery V.; Norko, Vadim E.

    2015-02-01

    Quality control of different coatings (colorful, paint, marker, safety, etc.) that are applied to the surface of various objects (both metallic and non-metallic) is an important problem. Also, there is a problem of dealing with counterfeit products. So it's necessary to distinguish the fake replicas of marking from the authentic marking of producer. To solve these problems, we propose an automated device (hardware and software complex) for analysis and control of spectral reflection characteristics, albedo and color parameters of extended (up to 150 mm × 150 mm) flat objects. It allows constructing the color image of the object surface as well as its multispectral images in selected regions of the spectrum. Herewith the color of the object surface can be calculated for various standard light sources (A, B, C, D65, E, F2, F7, F11, GE), or to any light source with a predetermined emission spectrum. The paper presents the description of construction and working principles of the proposed hardware and software complex. All color settings calculations correspond to the requirements and recommendations of CIE.

  7. Is discrimination enhanced at the boundaries of perceptual categories? A negative case

    Science.gov (United States)

    Danilova, M. V.; Mollon, J. D.

    2014-01-01

    The human visual system imposes discrete perceptual categories on the continuous input space that is represented by the ratios of excitations of the cones in the retina. Is discrimination enhanced at the boundaries between perceptual hues, in the way that discrimination may be enhanced at the boundaries between speech sounds in hearing? In the chromaticity diagram, the locus of unique green separates colours that appear yellowish from those that appear bluish. Using a two-alternative spatial forced choice and an adapting field equivalent to the Daylight Illuminant D65, we measured chromatic discrimination along lines orthogonal to the locus of unique green. In experimental runs interleaved with these performance measurements, we obtained estimates of the phenomenological boundary from the same observers. No enhancement of objectively measured discrimination was observed at the category boundary between yellowish and bluish hues. Instead, thresholds were minimal at chromaticities where the ratio of long-wave to middle-wave cone excitation was the same as that for the background adapting field. PMID:24807255

  8. Commonalities in social and non-social cognitive impairments in adults with autism spectrum disorder and schizophrenia.

    Science.gov (United States)

    Eack, Shaun M; Bahorik, Amber L; McKnight, Summer A F; Hogarty, Susan S; Greenwald, Deborah P; Newhill, Christina E; Phillips, Mary L; Keshavan, Matcheri S; Minshew, Nancy J

    2013-08-01

    Autism spectrum disorder (ASD) and schizophrenia are both conditions that are characterized by impairments in social and non-social cognition, yet commonalities in the magnitude and domains of cognitive deficits across these two conditions remain unclear. This study examined neurocognitive and social-cognitive functioning in 47 outpatients with schizophrenia, 43 verbal adults with ASD, and 24 healthy volunteers. A comprehensive neuropsychological battery assessing processing speed, attention, memory, and problem-solving domains was administered along with a social-cognitive battery of emotion processing. Results demonstrated large and significant impairments in emotion processing and neurocognition relative to healthy individuals in participants with autism (d=-.97 and -1.71, respectively) and schizophrenia (d=-.65 and -1.48, respectively). No significant differences were observed between those with ASD and schizophrenia on any cognitive domain assessed, and the areas of greatest impairment were identical across both disorders and included slowness in speed of processing and an inability to understand emotions. These findings indicate a high degree of similarity in the cognitive challenges experienced by verbal adults with autism and schizophrenia, and the potential need for trans-diagnostic remediation approaches to enhance cognition in these conditions.

  9. Chaotic phenomena of charged particles in crystal lattices.

    Science.gov (United States)

    Desalvo, Agostino; Giannerini, Simone; Rosa, Rodolfo

    2006-06-01

    In this article, we have applied the methods of chaos theory to channeling phenomena of positive charged particles in crystal lattices. In particular, we studied the transition between two ordered types of motion; i.e., motion parallel to a crystal axis (axial channeling) and to a crystal plane (planar channeling), respectively. The transition between these two regimes turns out to occur through an angular range in which the particle motion is highly disordered and the region of phase space spanned by the particle is much larger than the one swept in the two ordered motions. We have evaluated the maximum Lyapunov exponent with the method put forward by Rosenstein et al. [Physica D 65, 117 (1993)] and by Kantz [Phys. Lett. A 185, 77 (1994)]. Moreover, we estimated the correlation dimension by using the Grassberger-Procaccia method. We found that at the transition the system exhibits a very complex behavior showing an exponential divergence of the trajectories corresponding to a positive Lyapunov exponent and a noninteger value of the correlation dimension. These results turn out to be linked to a physical interpretation. The Lyapunov exponents are in agreement with the model by Akhiezer et al. [Phys. Rep. 203, 289 (1991)], based on the equivalence between the ion motion along the crystal plane described as a "string of strings" and the "kicked" rotator. The nonintegral value of the correlation dimension can be explained by the nonconservation of transverse energy at the transition.

  10. NUT-charged black holes in matter-coupled N=2, D=4 gauged supergravity

    Science.gov (United States)

    Colleoni, Marta; Klemm, Dietmar

    2012-06-01

    Using the results of Cacciatori, Klemm, Mansi, and Zorzan [J. High Energy Phys.JHEPFG1029-8479 05 (2008) 09710.1088/1126-6708/2008/05/097], where all timelike supersymmetric backgrounds of N=2, D=4 matter-coupled supergravity with Fayet-Iliopoulos gauging were classified, we construct genuine NUT-charged BPS black holes in anti-deSitter4 with nonconstant moduli. The calculations are exemplified for the SU(1,1)/U(1) model with prepotential F=-iX0X1. The resulting supersymmetric black holes have a hyperbolic horizon and carry two electric, two magnetic, and one NUT charge, which are however not all independent, but are given in terms of three free parameters. We find that turning on a NUT charge lifts the flat directions in the effective black hole potential, such that the horizon values of the scalars are completely fixed by the charges. We also oxidize the solutions to 11 dimensions, and find that they generalize the geometry found in the work of Gauntlett, Kim, Pakis, and Waldram [Phys. Rev. DPRVDAQ0556-2821 65, 026003 (2001)10.1103/PhysRevD.65.026003] corresponding to membranes wrapping holomorphic curves in a Calabi-Yau fivefold. Finally, a class of NUT-charged Nernst branes is constructed as well, but these have curvature singularities at the horizon.

  11. A non-classical view of the modulation of mineral precipitation by organic additives

    Science.gov (United States)

    Ruiz-Agudo, Encarnacion; Ruiz-Agudo, Cristina; Burgos-Cara, Alejandro; Putnis, Christine; Rodriguez-Navarro, Carlos; Putnis, Andrew

    2016-04-01

    inhibit the nucleation of solid phases. These effects are linked to the influence of these molecules on polymorph selection. As well, these additives can affect non-classical growth by oriented assembly of nanoparticles. REFERENCES Rodriguez-Navarro, C., Kudłacz, K., Cizer, Ö., Ruiz-Agudo, E., 2015. Formation of amorphous calcium carbonate and its transformation into mesostructured calcite. CrystEngComm 17 (1), 58-72. Ruiz Agudo, C; Ruiz Agudo, E; Putnis, C.V.; Putnis, A., 2015. Mechanistic principles of barite formation: from nanoparticles to micron-sized crystals. Crystal Growth & Design 15, 3724-3733. Verch, A., Gebauer, D., Antonietti, M., Cölfen, H., 2011. How to control the scaling of CaCO3: a "fingerprinting technique" to classify additives. Physical chemistry chemical physics: PCCP 13 (37), 16811-16820.

  12. PREFACE: Special issue: Proceedings of the Joint 19th AIRAPT and 41st EHPRG International Conference on High Pressure Science and Technology (Bordeaux, 7--11 July 2003)

    Science.gov (United States)

    Demazeau, Gérard

    2004-04-01

    , and was also by any measure a scientific success, with innumerable questions and discussions among this diverse group, and the scholarly contributions in this volume. We thank the participants, and Dr Richard Palmer, the Publisher of Journal of Physics: Condensed Matter and his staff for working to make this volume appear very quickly, thereby increasing the value of the papers to the community. We would also thank the Office of the vice-president for research at Université de Montréal, the Department of Physics and Astronomy at Arizona State University, the Department of Physics and Astronomy at Ohio University and the Canada Research Chair Program for financial assistance that made the meeting more enjoyable. We were both pleased to be part of this delightful occasion, and wish to take this last opportunity to wish Mike a happy birthday, and urge him to even greater achievements in coming years. Bibliography [1] Weaire D and Thorpe M F 1971 Electronic Properties of an Amorphous Solid: I. A Simple Tight Binding Theory Phys. Rev. B 4 2508--20 [2] Thorpe M F 1983 Continuous Deformations in Random Networks J. Non-Cryst. Solids 57 355-70 [3] Jacobs D J, Rader A J, Kuhn L A and Thorpe M F 2001 Protein Flexibilty Predictions using Graph Theory Proteins 44 150-65

  13. Exploring Jupiter's icy moons with old techniques and big facilities - new insights on sulfuric acid hydrates

    Science.gov (United States)

    Maynard-Casely, H. E.; Avdeev, M.; Brand, H.; Wallwork, K.

    2013-12-01

    ., AIP Conf Proc, 2007. 879: p. 879-882. [5] Liss, K.D., et al., Phys B-Cond Mat, 2006. 385-86: p. 1010-1012. [6] Maynard-Casely, H.E., K.S. Wallwork, and M. Avdeev, (In review). [7] Maynard-Casely, H.E., H.E.A. Brand, and K.S. Wallwork, J.of App.Cryst, 2012. 45: p.1198-1207. [8] Maynard-Casely, H.E., K.S. Wallwork, and H.E.A. Brand, (In Preparation). Stages of the crystal structure determination of sulfruic acid octahydrate a) the oxygen and sulfur postions were determined from the synchrotron x-ray data b) Once neutron diffraction data was collected Fourier difference methods were used to locate hydrogen positions to determine c) the full structure of sulfuric acid octahydrate.

  14. Synchrotron X-ray Scattering from Self-organized Soft Nanostructures in Clays

    Science.gov (United States)

    Fossum, J. O.

    2009-04-01

    . Gog, C. Venkataraman, Observations of orientational ordering in aqueous suspensions of a nano-layered silicate, ENERGY The International Journal 30, 873 (2005). 2. D. M. Fonseca, Y. Méheust, J. O. Fossum, K. D. Knudsen, K. J. Måløy and K. P. S. Parmar, Phase behavior of platelet-shaped nanosilicate colloids in saline solutions: A small-angle X-ray scattering study J. Appl. Cryst. 40 292 (2007) 3. E. N. de Azevedo, M. Engelsberg, J. O. Fossum, R. E. de Souza, Anisotropic water diffusion in nematic self-assemblies of clay nano-platelets suspended in water, Langmuir 23, 5100 (2007) 4. Nils Ivar Ringdal, Master thesis, Department of Physics, NTNU (2008) 5. J.O. Fossum, Y. Meheust, K.P.S. Parmar, K.D. Knudsen, K.J. Maloy, D.d.M. Fonseca, Intercalation-enhanced electric polarization and chain formation of nano-layered particles, Europhys. Lett., 74, 438 (2006), and in the Scientific Highlights 2006 of the European Synchrotron Radiation Facility - ESRF (2007) 6. K.P.S. Parmar, Y. Meheust, B. Schelderupsen and J.O. Fossum, Electrorheological suspensions of laponite in oil: rheometry studies, Langmuir 24,1814 (2008) 7. F. Bergaya, B. K. G. Theng, and G. Lagaly, editors. Handbook of Clay Science. Elsevier (2006)

  15. Opal instability: a relationship between water and microstructure?

    Science.gov (United States)

    Chauviré, Boris; Thomas, Paul; Rondeau, Benjamin; Fritsch, Emmanuel

    2017-04-01

    instability. The identification of the main factors controlling the destabilization will lead to the development of a non-destructive method for the categorization of gem-stability, increasing confidence in this gemstone for dealers, cutters and the consumer. References Aguilar B., Fritsch E., Ostroumov M., Barreau A. (2004) Why do opal die? An investigation of destabilization by whitening. 32nd Inter. Geol. Congress, Florence, Italy, 20-28 Aôut. Poster. Aguilar Reyes B.O, Ostrooumov M., Fritsch E. (2005) Estudio mineralogico de la desestabilizacion de opalos mexicanos. Revista Mexicana de Ciencas Geologicas 22(3), 391-400. Paris M, Fritsch E, Aguilar Reyes BO (2007) 1H, 29Si and 27Al NMR study of the destabilization process of a paracrystalline opal from Mexico. J. Non Cryst. Solids 353, 1650-1656. Pearson G (1985) Role of Water in Cracking of Opal. The Aust. Gemol. 15, 435-445. Rondeau B., Fritsch E., Mazzero F., Gauthier J.-P. (2011) The craze for stability. InColor 18, 42-45.

  16. Analyses of Cometary Silicate Crystals: DDA Spectral Modeling of Forsterite

    Science.gov (United States)

    Wooden, Diane

    2012-01-01

    Comets are the Solar System's deep freezers of gases, ices, and particulates that were present in the outer protoplanetary disk. Where comet nuclei accreted was so cold that CO ice (approximately 50K) and other supervolatile ices like ethane (C2H2) were preserved. However, comets also accreted high temperature minerals: silicate crystals that either condensed (greater than or equal to 1400 K) or that were annealed from amorphous (glassy) silicates (greater than 850-1000 K). By their rarity in the interstellar medium, cometary crystalline silicates are thought to be grains that formed in the inner disk and were then radially transported out to the cold and ice-rich regimes near Neptune. The questions that comets can potentially address are: How fast, how far, and over what duration were crystals that formed in the inner disk transported out to the comet-forming region(s)? In comets, the mass fractions of silicates that are crystalline, f_cryst, translate to benchmarks for protoplanetary disk radial transport models. The infamous comet Hale-Bopp has crystalline fractions of over 55%. The values for cometary crystalline mass fractions, however, are derived assuming that the mineralogy assessed for the submicron to micron-sized portion of the size distribution represents the compositional makeup of all larger grains in the coma. Models for fitting cometary SEDs make this assumption because models can only fit the observed features with submicron to micron-sized discrete crystals. On the other hand, larger (0.1-100 micrometer radii) porous grains composed of amorphous silicates and amorphous carbon can be easily computed with mixed medium theory wherein vacuum mixed into a spherical particle mimics a porous aggregate. If crystalline silicates are mixed in, the models completely fail to match the observations. Moreover, models for a size distribution of discrete crystalline forsterite grains commonly employs the CDE computational method for ellipsoidal platelets (c:a:b=8

  17. Crystal structures of a novel NNN pincer ligand and its dinuclear titanium(IV alkoxide pincer complex

    Directory of Open Access Journals (Sweden)

    Jakub Pedziwiatr

    2017-02-01

    is found in either one, perhaps due to the bulky groups around them. One of the ethyl groups of the ether ligand of 1 is disordered and refined in two parts with site-occupation factors of 0.812 (8 and 0.188 (8. One and a half toluene solvent molecules are also present in the asymmetric unit of 2. The toluene molecules were significantly disordered and could not be modeled properly, thus SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] was used to remove their contributions to the overall intensity data.

  18. 用于数码显微镜的白平衡校正方法%A White Balance Method for Digital Microscope

    Institute of Scientific and Technical Information of China (English)

    窦江龙; 刘岩; 刘鹏; 余飞鸿

    2012-01-01

    提出了一种用于数码显微镜的非线性白平衡方法.以标准D65光源光照下孟赛尔色卡每个色块的XYZ三刺激值和所成图像中的RGB值为训练样本,用神经网络建立不同数码显微镜拍摄的RGB输出与XYZ三刺激值之间的关系;再通过Estevens矩阵把XYZ三刺激值转换成人眼感光器所接受到的刺激值,并进行非线性计算;最后把计算结果转换回RGB空间,从而得到白平衡后的图像.实验结果表明,该方法所得的白平衡校正结果更加接近标准白光照射下的图像颜色.在光源色纯度较高的情况下,采用调整通道增益的方法变化幅度较大,而采用本文提出方法结果更加稳定;特别是当光源的色纯度过大使得图像中某个颜色通道的值接近0的时候,用调整三通道增益的方法已经完全失去了校正作用,而采用本文中的非线型方法仍然可以得到好的校正结果.同时,此方法中建立的神经网络模型反映的是成像设备的RGB空间到XYZ空间的转换特性,对于不同的光照条件,此特性不变,因此对于不同光源不需要分别建立神经网络模型.%A new non-linear white balance method is proposed. Taking XYZ stimulus and RGB values of each color block in Munsell color chart illuminated by D65 light source as training samples. A BP neural network mapping relation is built between digit-image RGB values of standard Munsell color chart and XYZ stimulus. Then Estevens matrix is introduced, which is used in translating XYZ stimulus to cone stimulus. After non-linear calculation, the results are translated back into digit-image RGB, values and an image after white balance is produced. It is indicated that this method gives a correct result much closer to image of objects illuminated by standard light sources. In the case of high purity light sources, a large volatility exists in adjusting channel-gains, while a stable result using the proposed method. Especially when the

  19. Identification of Escherichia coli O157:H7 meat processing indicators for fresh meat through comparison of the effects of selected antimicrobial interventions.

    Science.gov (United States)

    Marshall, K M; Niebuhr, S E; Acuff, G R; Lucia, L M; Dickson, J S

    2005-12-01

    Fresh meat products can become contaminated with the pathogen Escherichia coli O157:H7 during the slaughter process; therefore, an E. coli O157:H7 indicator to verify the effectiveness of process controls in slaughter establishments would be extremely useful. The hides of 20 beef cattle were sampled, and 113 bacterial isolates were obtained. Thirteen of these isolates representing four genera, Escherichia, Enterobacter, Providencia, and Serratia, were selected based on growth and biochemical characteristics similar to those of five clinical strains of E. coli O157:H7. The temperature sensitivity was determined for the individual isolates and the five E. coli O157:H7 strains at 55 and 65 degrees C. D65-values for all 13 isolates were not significantly different from D65-values of the E. coli O157:H7 strains. E. coli isolates were the only isolates whose D55-values were not significantly different from those of the E. coli O157:H7 strains. E. coli isolates P3 and P68 were more resistant to the effects of 55 degrees C than were the other E. coli isolates but were not significantly different from E. coli O157:H7 WS 3331 (P > 0.05). The remaining E. coli isolates (P1, P8, and P14) were not significantly different from E. coli O157:H7 strains ATCC 35150, ATCC 43894, ATCC 43895, and WS 3062 (P > 0.05). Prerigor lean and adipose beef carcass tissue was artificially contaminated with stationary-phase cultures of the five E. coli beef cattle isolates or a cocktail of five E. coli O157:H7 strains in a fecal inoculum. Each tissue sample was processed with the following microbial interventions: 90 degrees C water; 90 degrees C water followed by 55 degrees C 2% lactic acid; 90 degrees C water followed by 20 degrees C 2% lactic acid; 20 degrees C water followed by 20 degrees C 2% lactic acid; 20 degrees C water followed by 20 degrees C 20 ppm chlorine; and 20 degrees C water followed by 20 degrees C 10% trisodium phosphate. The appropriateness of the E. coli isolates as potential

  20. Film with anthocyanins as an indicator of chilled pork deterioration Filme com antocianinas como indicador da deterioração de carne suína refrigerada

    Directory of Open Access Journals (Sweden)

    Luana Baptista Golasz

    2013-02-01

    Full Text Available An indicator can be defined as a substance which indicates the presence or absence of another substance or the degree of a certain reaction through characteristic changes, especially color. Therefore, the aim of this work is to evaluate the performance of a bio-based film with anthocyanin as an indicator of chilled pork deterioration. A film made of cassava starch, glycerol, and grape anthocyanins was prepared using the casting technique. Pork loin samples were put in Petri dishes containing an anthocyanin film on the bottom and stored at 4 ºC. Psychrotrophic microorganism count and the pH of the pork loin samples were analyzed for a 14 day- period. At the same time, the films were subjected to colorimetric analysis using D65 illuminant and the CIELAB system. Chroma and hue angle data for these films were evaluated by Anova and Dunnett's test. An increase in the microbial population and in the pH was observed over the storage period as result of pork deterioration. Color changes were also identified in the film. However, only at the beginning of the storage period was it possible to establish a correlation between film color and pork deterioration. The shelf life end-point could not be clearly detected by the film.Um indicador pode ser definido como uma substância que indica a presença ou ausência de outra substância ou o grau de avanço de uma reação. Neste contexto, o objetivo deste trabalho é avaliar o desempenho de um filme com antocianinas como indicador da deterioração em carne suína refrigerada. Deste modo, um filme de fécula de mandioca, glicerol e antocianinas foi elaborado segundo a técnica de casting. Porções de lombo suíno foram colocadas em placas de Petri com um filme de antocianinas no fundo e foram armazenadas a 4 ºC. Durante 14 dias, foram avaliados a contagem de microrganismos psicrotróficos e o pH da carne. Paralelamente, os filmes foram submetidos à análise colorimétrica usando o iluminante D65 e o

  1. Rapid Calculation of LED Display Color Gamut Boundary Based on CORDIC Iteration Method%CORDIC迭代法快速计算LED显示屏色域边界

    Institute of Scientific and Technical Information of China (English)

    邓意成; 王瑞光; 陈宇; 张鑫

    2013-01-01

    针对色域映射过程中快速并精确地计算出任意映射线与色域边界交点坐标的问题,提出一种基于改进的CORDIC算法的迭代逼近求解方法.该方法利用CIE LUV颜色空间的特性可沿映射线逼近边缘交点.无需边界搜索和插值计算过程,可大量节省存储器资源和计算时间,并具有较高的计算精度和广泛的适用性.文章详细分析了算法的计算原理、精度和速度,并以LED显示屏为例,在D65标准光源下进行边界拟合并做出误差分析.实验结果表明:12次迭代运算后,拟合边界非常光滑,最大色差值仅为0.16,计算500个映射线交点的总计算时间约为1 s.与插值类计算方法相比,最大色差值降低了2.15,计算时间从10 s降低到1 s,速度提高了近10倍.

  2. A comparison and assessment on various color dimensions from two base metal alloys in ceramometal disks

    Directory of Open Access Journals (Sweden)

    Nokar S

    2004-02-01

    Full Text Available Color matching and accurate shade selection are the challenging problems common"nto restorative dentistry. In ceramometal restorations, the type of substructure alloy affects the final color of"nbonded porcelain. Nickel- chromium alloy is the most commonly used one that its Iranian product, namely"nMinalux, is similar to Verabond2."nPurpose: The aim of this study was to assess and compare various color dimensions resulting from Minalux"nand Verabond2 alloys."nMaterials and Methods: Nine disks, approximately 16 mm in diameter and 0.5 mm thickness, were cast"nfrom each alloy. Then, porcelain Vita VMK68 A2 was baked onto the entire test disks, following the"nmanufacturer's instruction. Color samples, at the same time and under the same conditions, was measured by"nData color spectrophotometer in CIE Lab System and Munsel system under four light sources (A, C, D65 and"nTL81. Then MATLAB TOOL BOX Statistic 5.2 was used to determine mean and bilateral variance analysis."nResults: It was indicated that the F value on hue, value and chroma was less than of the table value stated"nwith 99% coefficient confidence, confirming Ho theory. In other words, there were not any significant"ndifferences between ceramometal disks made of Minalux and Verabond2 in the three dimensions of color."nConclusion: Having desirable physical, mechanical and biological properties, Verabond2 can be replaced by"nMinalux alloy.

  3. Orthogonal relations and color constancy in dichromatic colorblindness.

    Science.gov (United States)

    Pridmore, Ralph W

    2014-01-01

    This paper employs uniform color space to analyze relations in dichromacy (protanopia, deuteranopia, tritanopia). Fifty percent or less of dichromats represent the classical reduction form of trichromacy, where one of three cones is inoperative but normal trichromatic color mixture such as complementary colors (pairs that mix white) are accepted by the dichromat, whose data can thus be plotted to CIE chromaticity spaces. The remaining dichromats comprise many and varied more-complex gene arrays from mutations, recombinations, etc. Though perhaps a minority, the three reductionist types provide a simple standard, in genotype and phenotype, to which the more complex remainder may be compared. Here, previously published data on dichromacy are plotted and analyzed in CIELUV uniform color space to find spatial relations in terms of color appearance space (e.g., hue angle). Traditional residual (seen) hues for protanopia and deuteranopia (both red-green colorblindness) are yellow and blue, but analysis indicates the protanopic residual hues are more greenish yellow and reddish blue than in tradition. Results for three illuminants (D65, D50, B) imply four principles in the spatial structure of dichromacy: (1) complementarity of confusion hue pairs and of residual hue pairs; (2) orthogonality of confusion locus and residual hues locus at their intersection with the white point, in each dichromatic type; (3) orthogonality of protanopic and tritanopic confusion loci; and (4) inverse relations between protanopic and tritanopic systems generally, such that one's confusion hues are the other's residual hues. Two of the three dichromatic systems do not represent components of normal trichromatic vision as sometimes thought but are quite different. Wavelength shifts between illuminants demonstrate chromatic adaptation correlates exactly with that in trichromatic vision. In theory these results clarify relations in and between types of dichromacy. They also apply in Munsell and

  4. A systematic examination of colour development in synthetic ultramarine according to historical methods.

    Directory of Open Access Journals (Sweden)

    Ian Hamerton

    Full Text Available A number of historical texts are investigated to ascertain the optimum conditions for the preparation of synthetic ultramarine, using preparative methods that would have been available to alchemists and colour chemists of the nineteenth century. The effect of varying the proportion of sulphur in the starting material on the colour of the final product is investigated. The optimum preparation involves heating a homogenised, pelletised mixture of kaolin (100 parts, sodium carbonate (100 parts, bitumen emulsion (or any 'sticky' carbon source (12 parts and sulphur (60 parts at 750°C for ca. 4 hours. At this stage the ingress of air should be limited. The sample is allowed to cool in the furnace to 500°C, the ingress of air is permitted and additional sulphur (30 parts is introduced before a second calcination step is undertaken at 500°C for two hours. The products obtained from the optimum synthesis have CIE ranges of x  = 0.2945-0.3125, y  = 0.2219-0.2617, Y  = 0.4257-0.4836, L* = 3.8455-4.3682, a*  = 4.2763-7.6943, b* = -7.6772-(-3.3033, L  = 3.8455-4.3682, C = 5.3964-10.8693, h = 315.0636-322.2562. The values are calculated using UV/visible near infrared spectra using Lazurite [1], under D65 illumination, and the 1931 2° observer.

  5. A systematic examination of colour development in synthetic ultramarine according to historical methods.

    Science.gov (United States)

    Hamerton, Ian; Tedaldi, Lauren; Eastaugh, Nicholas

    2013-01-01

    A number of historical texts are investigated to ascertain the optimum conditions for the preparation of synthetic ultramarine, using preparative methods that would have been available to alchemists and colour chemists of the nineteenth century. The effect of varying the proportion of sulphur in the starting material on the colour of the final product is investigated. The optimum preparation involves heating a homogenised, pelletised mixture of kaolin (100 parts), sodium carbonate (100 parts), bitumen emulsion (or any 'sticky' carbon source) (12 parts) and sulphur (60 parts) at 750°C for ca. 4 hours. At this stage the ingress of air should be limited. The sample is allowed to cool in the furnace to 500°C, the ingress of air is permitted and additional sulphur (30 parts) is introduced before a second calcination step is undertaken at 500°C for two hours. The products obtained from the optimum synthesis have CIE ranges of x  = 0.2945-0.3125, y  = 0.2219-0.2617, Y  = 0.4257-0.4836, L* = 3.8455-4.3682, a*  = 4.2763-7.6943, b* = -7.6772-(-)3.3033, L  = 3.8455-4.3682, C = 5.3964-10.8693, h = 315.0636-322.2562. The values are calculated using UV/visible near infrared spectra using Lazurite [1], under D65 illumination, and the 1931 2° observer.

  6. Vitamin D in youth with Type 1 diabetes: prevalence of insufficiency and association with insulin resistance in the SEARCH Nutrition Ancillary Study

    Science.gov (United States)

    The, N. S.; Crandell, J. L.; Lawrence, J. M.; King, I. B.; Dabelea, D.; Marcovina, S. M.; D’Agostino, R. B.; Norris, J. M.; Pihoker, C.; Mayer-Davis, E. J.

    2013-01-01

    Aims To determine the prevalence of plasma vitamin D insufficiency in individuals with Type 1 diabetes and to determine the cross-sectional and longitudinal associations of plasma vitamin D with insulin resistance. Methods Participants from the SEARCH for Diabetes in Youth Study [n = 1426; mean age 11.2 years (sd 3.9)] had physician-diagnosed Type 1 diabetes [diabetes duration mean 10.2 months (sd 6.5)] with data available at baseline and follow-up (approximately 12 and 24 months after baseline). Insulin resistance was estimated using a validated equation. Cross-sectional and longitudinal multivariate logistic regression models were used to determine the association of plasma vitamin D with insulin resistance, adjusting for potential confounders. Results Forty-nine per cent of individuals had plasma vitamin D < 50 nmol/l and 26% were insulin resistant. In cross-sectional multivariate analyses, participants who had higher plasma vitamin D (65 nmol/l) had lower odds of prevalent insulin resistance than participants with lower plasma vitamin D (25 nmol/l) (odds ratio 0.70, 95% CI 0.57–0.85). This association was attenuated after additional adjustment for BMI z-score, which could be a confounder or a mediator (odds ratio 0.81, 95% CI 0.64–1.03). In longitudinal multivariate analyses, individuals with higher plasma vitamin D at baseline had lower odds of incident insulin resistance, but this was not significant (odds ratio 0.85, 95% CI 0.63–1.14). Conclusions Vitamin D insufficiency is common in individuals with Type 1 diabetes and may increase risk for insulin resistance. Additional prospective studies are needed to determine the association between plasma vitamin D and insulin resistance, and to further examine the role of adiposity on this association. PMID:23909945

  7. Updated version of an interim connection space LabPQR for spectral color reproduction: LabLab.

    Science.gov (United States)

    Cao, Qian; Wan, Xiaoxia; Li, Junfeng; Liang, Jingxing

    2016-09-01

    In this paper, we propose a new interim connection space (ICS) called LabLab, which is an updated version of LabPQR, to overcome the drawback that the last three dimensions of LabPQR have no definite colorimetric meanings. We extended and improved the method by which the first three dimensions of LabPQR are deduced to obtain an ICS consisting of two sets of CIELAB values under different illuminants, and the reconstructed spectra from LabLab were obtained by minimizing colorimetric errors by means of the computational formula of the CIE-XYZ tristimulus values combined with least-squares best fit. The improvement obtained from the proposed method was tested to compress and reconstruct the reflectance spectra of the 1950 Natural Color System color chips and more than 50,000 ISO SOCS color patches as well as six multispectral images acquired by multispectral image acquisition systems using 1600 glossy Munsell color chips as training samples. The performance was evaluated by the mean values of color differences between the original and reconstructed spectra under the CIE 1931 standard colorimetric observer and the CIE standard illuminants D50, D55, D65, D75, F2, F7, F11, and A as well as five multichip white LED light sources. The mean and maximum values of the root mean square errors between the original and reconstructed spectra were also calculated. The experimental results show that the proposed three LabLab interim connection spaces significantly outperform principal component analysis, LabPQR, XYZLMS, Fairman-Brill, and LabRGB in colorimetric reconstruction accuracy at the cost of slight reduction of spectral reconstruction accuracy and illuminant independence of color differences of the suggested LabLab interim connection spaces outperform other interim connection spaces. In addition, the presented LabLab interim connection spaces could be quite compatible with the extensively used colorimetric management system since each dimension has definite colorimetric

  8. Anion-dependent construction of a series of fluorescent coordination polymers based on 1D zinc∩4,4‧-bis(imidazol-1-yl)-biphenyl substrates

    Science.gov (United States)

    Zou, Kang-Yu; Zou, Qian; Han, Tong; Liu, Yi-Chen; Wang, Jun-Jie; Zhang, Xue; Li, Zuo-Xi

    2016-03-01

    In this work, the rod-like ligand 4,4‧-bis(imidazol-1-yl)-biphenyl (bibp) has been utilized as a building block to carry out counterion effects on the structural diversities of coordination polymers. A series of new zinc complexes, [Zn(trans-bibp)Cl2]∞ (1), [Zn(trans-bibp)Br2]∞ (2), {[Zn(cis-bibp)(Ac)2]·(H2O)}∞ (3), [Zn(trans-bibp)SO4]∞ (4), {[Zn2(cis-bibp)2(ipa)2]·(H2O)}∞ (5, H2ipa=isophthalic acid) and {[Zn(trans-bibp)(cis-bibp)]·(ClO4)2(CHCl3)2(CH3OH)}∞ (6) have been successfully synthesized. Complexes 1 and 2 are iso-structural, which show a 1D W-type chain [Zn(trans-bibp)]∞. Complex 3 exhibits a 2D wave-like layer formed by the hydrogen bond among the 1D linear chain [Zn(cis-bibp)]∞. Complex 4 displays a 2D fish-bone lattice, which is generated from connecting the 1D W-type chain [Zn(trans-bibp)]∞ by the μ2-SO42- . Complex 5 presents an interesting 2D-3D 65·8 architecture, including two 1D chains [Zn(ipa)]∞ and [Zn(cis-bibp)]∞. Complex 6 demonstrates a 2D wave-like layer [Zn(trans-bibp)(cis-bibp)]∞. The structural diversities among 1-6 have been carefully discussed, and the role of counterion in the self-assembly of coordination polymer have also been well documented from the coordination affinity and bridging mode. Furthermore, the solid-state fluorescence properties of 1-6 at room temperature have been studied.

  9. Spectral images browsing using principal component analysis and set partitioning in hierarchical tree

    Science.gov (United States)

    Ma, Long; Zhao, Deping

    2011-12-01

    Spectral imaging technology have been used mostly in remote sensing, but have recently been extended to new area requiring high fidelity color reproductions like telemedicine, e-commerce, etc. These spectral imaging systems are important because they offer improved color reproduction quality not only for a standard observer under a particular illuminantion, but for any other individual exhibiting normal color vision capability under another illuminantion. A possibility for browsing of the archives is needed. In this paper, the authors present a new spectral image browsing architecture. The architecture for browsing is expressed as follow: (1) The spectral domain of the spectral image is reduced with the PCA transform. As a result of the PCA transform the eigenvectors and the eigenimages are obtained. (2) We quantize the eigenimages with the original bit depth of spectral image (e.g. if spectral image is originally 8bit, then quantize eigenimage to 8bit), and use 32bit floating numbers for the eigenvectors. (3) The first eigenimage is lossless compressed by JPEG-LS, the other eigenimages were lossy compressed by wavelet based SPIHT algorithm. For experimental evalution, the following measures were used. We used PSNR as the measurement for spectral accuracy. And for the evaluation of color reproducibility, ΔE was used.here standard D65 was used as a light source. To test the proposed method, we used FOREST and CORAL spectral image databases contrain 12 and 10 spectral images, respectively. The images were acquired in the range of 403-696nm. The size of the images were 128*128, the number of bands was 40 and the resolution was 8 bits per sample. Our experiments show the proposed compression method is suitable for browsing, i.e., for visual purpose.

  10. Health-related quality of life, work productivity, and indirect costs among patients with irritable bowel syndrome with diarrhea.

    Science.gov (United States)

    Buono, Jessica L; Carson, Robyn T; Flores, Natalia M

    2017-02-14

    Irritable bowel syndrome (IBS) affects 10-15% of adults in the US, and is associated with significant impairment in health-related quality of life (HRQoL); however, information specific to the diarrhea subtype (IBS-D) is lacking. We assessed the impact of IBS-D on HRQoL, work productivity, and daily activities, and the associated indirect costs, among a sample of the US population. Respondents (≥18 years) from the 2012 US National Health and Wellness Survey who reported an IBS-D diagnosis by a physician or symptoms consistent with Rome II criteria for IBS-D were identified as having IBS-D. Controls included respondents without IBS-D or inflammatory bowel disease. HRQoL was assessed via the Short Form 36 Health Survey version 2 questionnaire and summarized into Mental and Physical Component Summary (MCS; PCS) scores and a Short Form-6 dimension (SF-6D) utility score. Work and activity impairment were assessed via the Work Productivity and Activity Impairment Questionnaire: General Health version (WPAI:GH), which measures absenteeism, presenteeism, overall work productivity loss, and daily activity impairment. Indirect costs were calculated using unit cost data from the Bureau of Labor Statistics and variables from the WPAI:GH. Generalized linear models were used to examine differences in health outcomes between respondents with IBS-D and controls, controlling for demographic and health characteristics. In total, 66,491 respondents (1102 IBS-D; 65,389 controls) were analyzed. Mean age was 48.7 years; 50% were female. Compared with controls, the IBS-D cohort reported significantly lower HRQoL (mean MCS: 45.16 vs. 49.48; p work productivity loss (20.7% vs. 13.2%; p work and daily activities, and higher indirect costs, imposing a substantial burden on patients and employers. These findings suggest a significant unmet need exists for effective IBS-D treatments.

  11. Influence of resin cement shade on the color and translucency of ceramic veneers

    Science.gov (United States)

    HERNANDES, Daiana Kelly Lopes; ARRAIS, Cesar Augusto Galvão; de LIMA, Erick; CESAR, Paulo Francisco; RODRIGUES, José Augusto

    2016-01-01

    ABSTRACT Objective This in vitro study evaluated the effect of two different shades of resin cement (RC- A1 and A3) layer on color change, translucency parameter (TP), and chroma of low (LT) and high (HT) translucent reinforced lithium disilicate ceramic laminates. Material and Methods One dual-cured RC (Variolink II, A1- and A3-shade, Ivoclar Vivadent) was applied to 1-mm thick ceramic discs to create thin RC films (100 µm thick) under the ceramics. The RC was exposed to light from a LED curing unit. Color change (ΔE) of ceramic discs was measured according to CIEL*a*b* system with a standard illuminant D65 in reflectance mode in a spectrophotometer, operating in the light range of 360-740 nm, equipped with an integrating sphere. The color difference between black (B) and white (W) background readings was used for TP analysis, while chroma was calculated by the formula C* ab=(a*2+b*2)½. ΔE of 3.3 was set as the threshold of clinically unacceptable. The results were evaluated by two-way ANOVA followed by Tukey's post hoc test. Results HT ceramics showed higher ΔE and higher TP than LT ceramics. A3-shade RC promoted higher ΔE than A1-shade cement, regardless of the ceramic translucency. No significant difference in TP was noted between ceramic discs with A1- and those with A3-shade cement. Ceramic with underlying RC showed lower TP than discs without RC. HT ceramics showed lower chroma than LT ceramics, regardless of the resin cement shade. The presence of A3-shade RC resulted in higher chroma than the presence of A1-shade RC. Conclusions Darker underlying RC layer promoted more pronounced changes in ceramic translucency, chroma, and shade of high translucent ceramic veneers. These differences may not be clinically differentiable. PMID:27556211

  12. Potentiating the cellular targeting and anti-tumor activity of Dp44mT via binding to human serum albumin: two saturable mechanisms of Dp44mT uptake by cells.

    Science.gov (United States)

    Merlot, Angelica M; Sahni, Sumit; Lane, Darius J R; Fordham, Ashleigh M; Pantarat, Namfon; Hibbs, David E; Richardson, Vera; Doddareddy, Munikumar R; Ong, Jennifer A; Huang, Michael L H; Richardson, Des R; Kalinowski, Danuta S

    2015-04-30

    Di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT) demonstrates potent anti-cancer activity. We previously demonstrated that 14C-Dp44mT enters and targets cells through a carrier/receptor-mediated uptake process. Despite structural similarity, 2-benzoylpyridine 4-ethyl-3-thiosemicarbazone (Bp4eT) and pyridoxal isonicotinoyl hydrazone (PIH) enter cells via passive diffusion. Considering albumin alters the uptake of many drugs, we examined the effect of human serum albumin (HSA) on the cellular uptake of Dp44mT, Bp4eT and PIH. Chelator-HSA binding studies demonstrated the following order of relative affinity: Bp4eT≈PIH>Dp44mT. Interestingly, HSA decreased Bp4eT and PIH uptake, potentially due to its high affinity for the ligands. In contrast, HSA markedly stimulated Dp44mT uptake by cells, with two saturable uptake mechanisms identified. The first mechanism saturated at 5-10 µM (B(max):1.20±0.04 × 10⁷ molecules/cell; K(d):33±3 µM) and was consistent with a previously identified Dp44mT receptor/carrier. The second mechanism was of lower affinity, but higher capacity (B(max):2.90±0.12 × 10⁷ molecules/cell; K(d):65±6 µM), becoming saturated at 100 µM and was only evident in the presence of HSA. This second saturable Dp44mT uptake process was inhibited by excess HSA and had characteristics suggesting it was mediated by a specific binding site. Significantly, the HSA-mediated increase in the targeting of Dp44mT to cancer cells potentiated apoptosis and could be important for enhancing efficacy.

  13. Do specular highlights and the daylight locus act as cues for estimating illumination color from a single object?

    Science.gov (United States)

    Nagai, Takehiro; Kaneko, Shigeyuki; Kawashima, Yuki; Yamauchi, Yasuki

    2017-02-01

    Specular highlights on the surface of an object can serve as cues for estimating illumination color, because highlights on many objects directly reflect illumination colors. In addition, we experience that illumination colors typically have chromaticities near the daylight locus in daily life, and this experience may possibly affect our estimation of the illumination color. In this study, we investigated the effects of specular highlights and object colors on the estimation of the illumination colors by human observers using images of a single object with specular highlights as stimuli. In the experiments, the colors of all pixels on an object with specular highlights changed from the reference D65 chromaticity to a test chromaticity in a trial. Observers judged whether this chromaticity change appeared to be induced by changing the object or by changing the illumination. In the control experiment, observers performed the same task for a stimulus of a mat object without specular highlights. Different values of hue and saturation were used as the test chromaticities. In the results, the chromaticity changes appeared more likely to be caused by changing the illumination when the test color had lower saturation. In addition, the ratios of "illumination changed" responses were slightly higher for objects with specular highlights than for objects without specular highlight. However, the ratios of "illumination changed" responses averaged across observers were not largely different across color directions. These results suggest that specular highlights slightly contribute to the estimation of illumination color, and that the daylight locus does not largely affect the estimation of the illumination color.

  14. Influence of resin cement shade on the color and translucency of ceramic veneers

    Directory of Open Access Journals (Sweden)

    Daiana Kelly Lopes HERNANDES

    Full Text Available ABSTRACT Objective This in vitro study evaluated the effect of two different shades of resin cement (RC- A1 and A3 layer on color change, translucency parameter (TP, and chroma of low (LT and high (HT translucent reinforced lithium disilicate ceramic laminates. Material and Methods One dual-cured RC (Variolink II, A1- and A3-shade, Ivoclar Vivadent was applied to 1-mm thick ceramic discs to create thin RC films (100 µm thick under the ceramics. The RC was exposed to light from a LED curing unit. Color change (ΔE of ceramic discs was measured according to CIEL*a*b* system with a standard illuminant D65 in reflectance mode in a spectrophotometer, operating in the light range of 360-740 nm, equipped with an integrating sphere. The color difference between black (B and white (W background readings was used for TP analysis, while chroma was calculated by the formula C*ab=(a*2+b*2½. ΔE of 3.3 was set as the threshold of clinically unacceptable. The results were evaluated by two-way ANOVA followed by Tukey's post hoc test. Results HT ceramics showed higher ΔE and higher TP than LT ceramics. A3-shade RC promoted higher ΔE than A1-shade cement, regardless of the ceramic translucency. No significant difference in TP was noted between ceramic discs with A1- and those with A3-shade cement. Ceramic with underlying RC showed lower TP than discs without RC. HT ceramics showed lower chroma than LT ceramics, regardless of the resin cement shade. The presence of A3-shade RC resulted in higher chroma than the presence of A1-shade RC. Conclusions Darker underlying RC layer promoted more pronounced changes in ceramic translucency, chroma, and shade of high translucent ceramic veneers. These differences may not be clinically differentiable.

  15. Orthogonal relations and color constancy in dichromatic colorblindness.

    Directory of Open Access Journals (Sweden)

    Ralph W Pridmore

    Full Text Available This paper employs uniform color space to analyze relations in dichromacy (protanopia, deuteranopia, tritanopia. Fifty percent or less of dichromats represent the classical reduction form of trichromacy, where one of three cones is inoperative but normal trichromatic color mixture such as complementary colors (pairs that mix white are accepted by the dichromat, whose data can thus be plotted to CIE chromaticity spaces. The remaining dichromats comprise many and varied more-complex gene arrays from mutations, recombinations, etc. Though perhaps a minority, the three reductionist types provide a simple standard, in genotype and phenotype, to which the more complex remainder may be compared. Here, previously published data on dichromacy are plotted and analyzed in CIELUV uniform color space to find spatial relations in terms of color appearance space (e.g., hue angle. Traditional residual (seen hues for protanopia and deuteranopia (both red-green colorblindness are yellow and blue, but analysis indicates the protanopic residual hues are more greenish yellow and reddish blue than in tradition. Results for three illuminants (D65, D50, B imply four principles in the spatial structure of dichromacy: (1 complementarity of confusion hue pairs and of residual hue pairs; (2 orthogonality of confusion locus and residual hues locus at their intersection with the white point, in each dichromatic type; (3 orthogonality of protanopic and tritanopic confusion loci; and (4 inverse relations between protanopic and tritanopic systems generally, such that one's confusion hues are the other's residual hues. Two of the three dichromatic systems do not represent components of normal trichromatic vision as sometimes thought but are quite different. Wavelength shifts between illuminants demonstrate chromatic adaptation correlates exactly with that in trichromatic vision. In theory these results clarify relations in and between types of dichromacy. They also apply in

  16. Synthesis of Zn1- x Co x Al2O4 Spinel Nanoparticles by Liquid-Feed Flame Spray Pyrolysis: Ceramic Pigments Application

    Science.gov (United States)

    Betancur Granados, Natalia; Yi, Eongyu; Laine, Richard M.; Restrepo Baena, Oscar Jaime

    2016-01-01

    Zn1- x Co x Al2O4 ( x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) spinel nanoparticles were synthesized by a liquid-feed flame spray pyrolysis (LF-FSP) method by combusting metallorganic precursor solutions to produce nanopowders with precise composition control. The precursor solutions were aerosolized into a methane/oxygen flame where it was combusted in an oxygen-rich environment to result in nanopowders at a single step. The nanopowders were analyzed by x-ray diffraction, Fourier transform infrared spectroscopy, colorimetry, field emission scanning electron microscopy, transmission electron microscopy, and BET (Brunauer-Emmett-Teller) N2 adsorption. Results show formation of spherical nanopowders with specific surface areas of 42 m2/g to 50 m2/g, which correspond to average particle sizes of 26 nm to 31 nm. Single-phase materials were obtained with a high control of composition, which indicates that LF-FSP is an excellent method to produce mixed-metal oxides for applications in which powder homogeneity is crucial. The products were evaluated for ceramic pigment application, where the ratio of Zn to Co was gradually changed to observe the color change in the structure with the increase of cobalt concentration. The resulting pigments were calcined at 1200°C, which aimed to identify the color stability after a high-temperature process, whereby the colors were measured using the color space CIE L*a*b* under standardized light, D65. Finally, the powders were tested for ceramic decoration using transparent glazes and ceramic bodies. The application was carried out at 1250°C to evaluate the color performance after a decoration process.

  17. Research for quantitative classification of dry red wine in uniform color space%均匀色空间下红葡萄酒颜色量化分级研究

    Institute of Scientific and Technical Information of China (English)

    陈晓艺; 张军翔; 王宏

    2015-01-01

    以宁夏贺兰山东麓产区2012年和2013年瓶储陈酿的13个红葡萄酒样品为材料,采用紫外可见分光光度法和国际照明委员会推荐的CIE L*a*b*均匀色空间参数,来量化葡萄酒的颜色指数,初步研究均匀色空间下红葡萄酒颜色的量化分级.数据量化结果表明:在标准光源D65下,所测试的红葡萄酒色相分为3级,紫红、胭脂红、宝石红;彩度分为5级,灰、淡、中、浓、鲜艳;明度分为5级,中等、稍亮、较亮、亮、明亮.建立CIE L* a*b*下的模型:Ry Cx(1-5) Lx(1-5)、RzCx(1-5)Lx(1-5)、RbCx(1-5)Lx(1-5),试验表明13种酒样分布在Ry C5+L2+、Ry C4+L3+、RzC4+L2+、RzC3+L3+、RzC3+L4+、Rz C2+ L4+、Rb C2+ L4+、Rb C+ L5+以上8级.

  18. Effect of resin shades on opacity of ceramic veneers and polymerization efficiency through ceramics.

    Science.gov (United States)

    Öztürk, Elif; Chiang, Yu-Chih; Coşgun, Erdal; Bolay, Şükran; Hickel, Reinhard; Ilie, Nicoleta

    2013-11-01

    The aim of this study was to assess the effect of different resin cement shades on the opacity and color difference of ceramics and to determine the polymerization efficiency of the resin cement at different shades after curing through ceramics. Two different ceramics (IPS e.max Press and IPS Empress(®)CAD, Ivoclar Vivadent) were used for this study. A light-cured veneer luting resin (Variolink Veneer, Ivoclar Vivadent) in four different shades of HV+1, HV+3, LV-1, and LV-3 was used for the colorimetric measurements. The color and spectral reflectance of the ceramics were measured according to the CIELab color scale relative to the standard illuminant D65 on a reflection spectrophotometer (ColorEye7000A, USA). Color differences (ΔE values) and the contrast ratios (CR) of the different groups of samples were calculated. In order to analyse the polymerization efficiency of the resin cements, the micromechanical properties of the resins were measured with an automatic microhardness indenter (Fisherscope H100C, Germany). The results were analysed using one-way ANOVA and Tukey's HSD post hoc tests (SPSS 18.0). The one-way ANOVA test showed that the values of ΔE and CR of the different specimen groups were significantly different (p<0.05). Group 1 (20.7 ± 0.5) (IPS-CAD without resin cement) exhibited the highest and group 10 (14.8 ± 0.5) (e.max:HV+3) exhibited the lowest ΔE value. Significant differences in the micromechanical properties were identified among the tested resin cements in different shades (p<0.05). Resin cement shade is an important factor for the opacity of a restoration. Furthermore, the resin shade affects the micromechanical properties of the underlying resin cement. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Molecular epidemiology of hepatitis B virus in Misiones, Argentina.

    Science.gov (United States)

    Mojsiejczuk, Laura Noelia; Torres, Carolina; Sevic, Ina; Badano, Inés; Malan, Richard; Flichman, Diego Martin; Liotta, Domingo Javier; Campos, Rodolfo Hector

    2016-10-01

    Hepatitis B virus (HBV) infection is a major public health problem worldwide. The aims of this study were to describe the molecular epidemiology of HBV in the Province of Misiones, Argentina and estimate the phylodynamic of the main groups in a Bayesian coalescent framework. To this end, partial or complete genome sequences were obtained from 52 blood donor candidates. The phylogenetic analysis based on partial sequences of S/P region showed a predominance of genotype D (65.4%), followed by genotype F (30.8%) and genotype A as a minority (3.8%). At subgenotype level, the circulation of subgenotypes D3 (42.3%), D2 (13.5%), F1b (11.5%) and F4 (9.6%) was mainly identified. The Bayesian coalescent analysis of 29 complete genome sequences for the main groups revealed that the subgenotypes D2 and D3 had several introductions to the region, with ancestors dating back from 1921 to 1969 and diversification events until the late '70s. The genotype F in Misiones has a more recent history; subgenotype F4 isolates were intermixed with sequences from Argentina and neighboring countries and only one significant cluster dated back in 1994 was observed. Subgenotype F1b isolates exhibited low genetic distance and formed a closely related monophyletic cluster, suggesting a very recent introduction. In conclusion, the phylogenetic and coalescent analyses showed that the European genotype D has a higher circulation, a longer history of diversification and may be responsible for the largest proportion of chronic HBV infections in the Province of Misiones. Genotype F, especially subgenotype F1b, had a more recent introduction and its diversification in the last 20years might be related to its involvement in new transmission events.

  20. Optical properties of base dentin ceramics for all-ceramic restorations.

    Science.gov (United States)

    Shiraishi, Takanobu; Wood, Duncan J; Shinozaki, Nobuya; van Noort, Richard

    2011-02-01

    The study was conducted to compare the optical parameters of VM7(®) M-shade base dentin ceramics (VITA, Germany) for all ceramic restorations to the chemical composition across the 3D-MASTER(®) shade system. Three disc samples, 13 mm diameter and 1.4 mm thickness, were produced for each M-shade following the manufacturer's instructions. Each disc was ground and polished to a thickness of 1.0 mm. Spectral light transmittance and reflectance data were recorded in the visible spectrum under the standard illuminant D65 and 2° observer at 10 nm intervals by using a computer-controlled spectrophotometer. Opacity, translucency and opalescence parameters were determined for each sample. (1) Spectral transmittance and reflectance in the short-wavelength range systematically decreased with increasing chroma number (M1, M2, M3) when compared within the same value (lightness) group. (2) Spectral transmittance and reflectance decreased systematically across the whole visible spectrum with increasing value group number when compared within the same chroma group. (3) Analysis of relationship between chemical composition and various optical parameters for all the samples showed the significant contribution of ZrO₂ and Y₂O₃ substances to optical properties of the present material. Systematic variations in optical properties of VM7(®) M-shade base dentin ceramics were observed throughout the 3D-MASTER(®) shade system and were suggested to be caused by the fine structure of the sample which can interfere with shorter wavelengths in the visible spectrum. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. P1-13: Color Induction from Surround Color under Interocular Suppression

    Directory of Open Access Journals (Sweden)

    Ichiro Kuriki

    2012-10-01

    Full Text Available The effect of surround colors on color appearance is known to subserve color constancy in humans, but how multiple mechanisms in the visual system are involved in this effect is controversial. We used an interocular-suppression technique to examine how the effect occurs at the level higher than the interaction of binocular information. A test color chip (1.7 × 1.7 deg visual angle was presented in a static surround either with continuous-flash suppression in the dominant eye (CFS condition to make the surround inperceptible or without the suppression (no-CFS condition. The surround stimulus was either a Mondrian or a uniform field of the same mean chromaticity. Stimuli were simulated OSA color chips under red, white (D65, or green illuminant color and were presented on a CRT display. Unique yellows were measured by asking the subjects to judge whether the test stimulus appeared reddish or greenish. Two sizes of the surround stimuli (widths of 1 deg and 4 deg were used. Results showed significant shifts in unique yellow even under the CFS conditions, except for the 1 deg uniform-surround condition. Under the no-CFS condition, the shifts showed remarkable difference between subjects, except for the 4 deg Mondrian-surround condition. Interestingly, trends of the shifts showed high consistency within each subject, across conditions. These results indicate that mechanisms at both higher and lower levels than the neuronal site of interocular suppression are involved, and that the color shifts follow each subject's strategy in the higher-order mechanisms when only insufficient clues are available in the surround to estimate illuminant color.

  2. ACE基因Ⅰ/D多态性与中国越野滑雪运动员运动能力的相关性研究%Correlation of ACE Gene Ⅰ/D Polymorphism and Chinese Cross-country Skiers' Skiing Performance

    Institute of Scientific and Technical Information of China (English)

    李丽; 韩伟; 于英君

    2012-01-01

    杰出的运动能力与运动相关基因的多态性密切相关.采用PCR-RFLP方法测定30名越野滑雪运动员与30名普通大学生的基因的多态性.研究结果表明,对照组等位基因频率为Ⅰ=35%,D=65%,基因型频率为Ⅱ=20%,Ⅰ/D=30%,DD=50%,越野滑雪运动员等位基因频率为Ⅰ=51.7%,D =48.3%,基因型频率为Ⅱ=36.7%,Ⅰ/D=30%,DD=33.3%.经卡方检验符合Hardy-Weinberg遗传平衡定律,两组间基因型频率和等位基因频率有差异,Ⅱ基因型和Ⅰ等位基因的频率高于对照组(P<0.1).ACE基因Ⅰ/D多态性与中国黑龙江省越野滑运动员运动能力有相关性,提示可作为基因选材的指标.探讨中国越野滑雪运动员运动能力与ACE基因Ⅰ/D多态性的关联,为越野滑雪运动员的基因选材提供前期探讨性的理论依据与基础数据.

  3. Color calibration of a CMOS digital camera for mobile imaging

    Science.gov (United States)

    Eliasson, Henrik

    2010-01-01

    As white balance algorithms employed in mobile phone cameras become increasingly sophisticated by using, e.g., elaborate white-point estimation methods, a proper color calibration is necessary. Without such a calibration, the estimation of the light source for a given situation may go wrong, giving rise to large color errors. At the same time, the demands for efficiency in the production environment require the calibration to be as simple as possible. Thus it is important to find the correct balance between image quality and production efficiency requirements. The purpose of this work is to investigate camera color variations using a simple model where the sensor and IR filter are specified in detail. As input to the model, spectral data of the 24-color Macbeth Colorchecker was used. This data was combined with the spectral irradiance of mainly three different light sources: CIE A, D65 and F11. The sensor variations were determined from a very large population from which 6 corner samples were picked out for further analysis. Furthermore, a set of 100 IR filters were picked out and measured. The resulting images generated by the model were then analyzed in the CIELAB space and color errors were calculated using the ΔE94 metric. The results of the analysis show that the maximum deviations from the typical values are small enough to suggest that a white balance calibration is sufficient. Furthermore, it is also demonstrated that the color temperature dependence is small enough to justify the use of only one light source in a production environment.

  4. RETRACTED: Bezafibrate improves mitochondrial function in the CNS of a mouse model of mitochondrial encephalopathy.

    Science.gov (United States)

    Noe, Natalie; Dillon, Lloye; Lellek, Veronika; Diaz, Francisca; Hida, Aline; Moraes, Carlos T; Wenz, Tina

    2013-09-01

    This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This retraction was suggested by the University of Cologne Investigation committee and seconded by the authors who the journal was able to contact (Wenz, T., Dillon, L., Diaz, F., Hida, A., and Moraes, C.T.). Following an investigation of the last author, Dr. Tina Wenz, by the University of Cologne, Germany, the university determined that data presented in this article have been inappropriately manipulated https://www.portal.uni-koeln.de/9015.html?&tx_news_pi1%5Bnews%5D=4335&tx_news_pi1%5Bcontroller%5D=News&tx_news_pi1%5Baction%5D=detail&cHash=1deb8399d7f796d65ca9f6ae4764a1ce. Specifically, western blot images in Figure 5F (tubulin in cortex), 2F (COXI in hippocampus) and 3B (Sod2 in hippocampus) were re-used from an earlier article published elsewhere [Increased muscle PGC-1alpha expression protects from sarcopenia and metabolic disease during aging" Wenz T, Rossi SG, Rotundo RL, Spiegelman BM, and Moraes CT. Proc Natl Acad Sci U S A. 2009;106:20405-10, doi: 10.1073/pnas.0911570106] representing different experimental findings. Therefore, whether or not the main conclusions are still valid, the authors request retraction of this publication because the scientific integrity of the study was compromised. The authors sincerely apologize to the scientific community. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. A systematically tested intervention for managing reactive depression.

    Science.gov (United States)

    Smith, Carol E; Leenerts, Mary Hobbs; Gajewski, Byron J

    2003-01-01

    Patients and family caregivers repeatedly experience reactive depression that leads to medication errors, mismanagement of chronic disease, and poor self-care. These problems place them at high-risk for malnutrition, infection, heart diseases, and psychiatric sequelae. A secondary data analysis compared findings across a series of studies to evaluate the acceptability, effectiveness, and cost of a therapeutic writing intervention to reduce reactive depression, a common and frequently recurring adverse symptom. Secondary analysis of data from the series of studies was conducted. Data came from patients requiring lifelong, daily central intravenous catheter infusion of home total parenteral nutrition necessitated by nonmalignant bowel disease and their family caregivers who assist with this complex home care. Variables combined across the studies were pre- and postintervention scores from the Center for Epidemiological Studies-Depression Scale (CES-D), the number of weeks patients wrote in their diaries (adherence), and the written content in the diaries. Content analysis was used to analyze written data. The intervention materials and nurses' time spent were averaged across studies to determine costs. The weighted average baseline CES-D scores across studies for patients (17.94) and caregivers (15.75) showed the presence of depression. After journal writing had been used for an average of 10.4 weeks across studies, the effect sizes of the between (d =.27) and within (d =.65) patient group scores indicated moderate to large improvement in depression. Themes from written diaries showed that missing out on activities, financial worries, strain related to the severe illness, and the complexity of home care were related to depression across the studies. The intervention was acceptable to participants, effective for managing reactive depression, and low in cost. The next steps will address testing for the longitudinal effects of the intervention.

  6. A 256 x 256 2-D array transducer with row-column addressing for 3-D rectilinear imaging.

    Science.gov (United States)

    Seo, Chi Hyung; Yen, Jesse T

    2009-04-01

    We present simulation and experimental results from a 5-MHz, 256 x 256 2-D (65,536 elements, 38.4 x 38.4 mm) 2-D array transducer with row-column addressing. The main benefits of this design are a reduced number of interconnects, a modified transmit/receive switching scheme with a simple diode circuit, and an ability to perform volumetric imaging of targets near the transducer with transmit beamforming in azimuth and receive beamforming in elevation. The final dimensions of the transducer were 38.4 mm x 38.4 mm x 300 microm. After a row-column transducer was prototyped, the series resonance impedance was 104 Omega at 5.4 MHz. The measured -6 dB fractional bandwidth was 53% with a center frequency of 5.3 MHz. The SNR at the transmit focus was measured to be 30 dB. At 5 MHz, the average nearest neighbor crosstalk was -25 dB. In this paper, we present 3-D images of both 5 pairs of nylon wires embedded in a clear gelatin phantom and an 8 mm diameter cylindrical anechoic cyst phantom acquired from a 256 x 256 2-D array transducer made from a 1-3 composite. We display the azimuth and elevation B-scans as well as the C-scan for each image. The cross-section of the wires is visible in the azimuth B-scan, and the long axes can be seen in the elevation B-scan and C-scans. The pair of wires with 1-mm axial separation is discernible in the elevational B-scan. When a single wire from the wire target phantom was used, the measured lateral beamwidth was 0.68 mm and 0.70 mm at 30 mm depth in transmit beamforming and receive beamforming, respectively, compared with the simulated beamwidth of 0.55 mm. The cross-section of the cyst is visible in the azimuth B-scan whereas the long axes can be seen as a rectangle in the elevation B-scan and C-scans.

  7. Color-Matching and Blending-Effect of Universal Shade Bulk-Fill-Resin-Composite in Resin-Composite-Models and Natural Teeth.

    Science.gov (United States)

    Abdelraouf, Rasha M; Habib, Nour A

    2016-01-01

    Objectives. To assess visually color-matching and blending-effect (BE) of a universal shade bulk-fill-resin-composite placed in resin-composite-models with different shades and cavity sizes and in natural teeth (extracted and patients' teeth). Materials and Methods. Resin-composite-discs (10 mm × 1 mm) were prepared of universal shade composite and resin-composite of shades: A1, A2, A3, A3.5, and A4. Spectrophotometric-color-measurement was performed to calculate color-difference (ΔE) between the universal shade and shaded-resin-composites discs and determine their translucency-parameter (TP). Visual assessment was performed by seven normal-color-vision-observers to determine the color-matching between the universal shade and each shade, under Illuminant D65. Color-matching visual scoring (VS) values were expressed numerically (1-5): 1: mismatch/totally unacceptable, 2: Poor-Match/hardly acceptable, 3: Good-Match/acceptable, 4: Close-Match/small-difference, and 5: Exact-Match/no-color-difference. Occlusal cavities of different sizes were prepared in teeth-like resin-composite-models with shades A1, A2, A3, A3.5, and A4. The cavities were filled by the universal shade composite. The same scale was used to score color-matching between the fillings and composite-models. BE was calculated as difference in mean-visual-scores in models and that of discs. Extracted teeth with two different class I-cavity sizes as well as ten patients' lower posterior molars with occlusal caries were prepared, filled by universal shade composite, and assessed similarly. Results. In models, the universal shade composite showed close matching in the different cavity sizes and surrounding shades (4 ≤ VS composite showed good-matching (VS = 3-3.3, BE = -0.9-2.1). Conclusions. Color-matching of universal shade resin-composite was satisfactory rather than perfect in patients' teeth.

  8. Colour parameters and shade correspondence of CAD-CAM ceramic systems.

    Science.gov (United States)

    Della Bona, Alvaro; Pecho, Oscar E; Ghinea, Razvan; Cardona, Juan C; Pérez, María M

    2015-06-01

    To evaluate colour differences between (1) CAD-CAM ceramic systems considering shades A1, A2 and A3 and the corresponding nominal shade of VC (Vita Classical shade guide) and (2) shades A1-A2, A2-A3 and A1, A2 and A3 within the same ceramic system. Samples of shades A1, A2 and A3 were fabricated (n=5) from CAD-CAM ceramic blocks (IPS e.max(®) CAD LT and HT, IPS Empress(®) CAD LT and HT, Paradigm™ C, and VITABLOCS(®) Mark II) and polished to 1.0±0.01mm in thickness. Spectral reflectance and colour coordinates were measured using a spectroradiometer inside a viewing booth using the CIE D65 illuminant and the d/0° geometry. Spectral reflectance curves were compared using VAF coefficient and were statistically analyzed using Kruskal-Wallis and the Mann-Whitney U test (α=0.05). Colour coordinates were statistically analyzed using one-way ANOVA, Tukey's test with Bonferroni correction (α=0.001). All colour differences (ΔEab(*) and ΔE00) were analyzed through comparisons with the PT - perceptibility and AT - acceptability thresholds for dental ceramics. ΔE between ceramic systems and its corresponding shade ranged from 6.32 to 13.42 (ΔEab(*)) and 4.48 to 9.30 (ΔE00). ΔE between shades A1-A2, A2-A3 and A1, A2 and A3 ranged, respectively, 1.93-4.82, 1.22-5.59 and 3.63-8.84 (ΔEab(*)); 1.54-3.87, 1.03-3.90 and 2.95-6.51 (ΔE00). Considering the corresponding nominal shade from VC, none of the ceramic systems showed colour differences below the AT. In addition, some ceramic systems showed colour differences below AT (shades A1-A2 and A2-A3) and below PT (shades A2-A3). Careful adjustments should be made to the final shade of CAD-CAM ceramic restorations to reach a clinically acceptable shade match. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Influence of tab and disk design on shade matching of dental porcelain.

    Science.gov (United States)

    Barrett, Allyson A; Grimaudo, Nicholas J; Anusavice, Kenneth J; Yang, Mark C K

    2002-12-01

    Given the complexity of tooth color, the variations of shade within each tooth, and translucency, it is difficult to view only one small area and select a shade match for restorations. This study tested the effect of specimen design on porcelain shade matching, hypothesizing that flat disks would be matched to one another with more accuracy than tooth-shaped tabs to tabs. All testing was conducted in a Macbeth SpectraLight booth with D65 illumination. Seventy-three senior dental students (25 women and 48 men; mean age, 27 years) were asked to match selected Vita porcelain disks and Vita shade tabs to like specimens. The design order, namely matching tabs or disks first, was alternated for each observer. The specimens were handed to the observer individually. No time limit for matching was imposed, although each observer was given explicit instructions related to the observation and handling of the specimens. Upon completion of the matching exercises, each student received his or her standardized test results and reviewed the matching results. The time for testing and review was approximately 20 minutes per observer. An analysis of variance, with gender and order as 2 factors that could affect matching scores, was performed (P <.05). The mean matching scores were 78.4% for disks and 73.6% for tabs (P=.119). Female observers matched 76.5% of the disks and 77.5% of the tabs, whereas male observers matched 79.4% of the disks and 71.6% of the tabs (P=.054). Matching disks before tabs yielded equivalent levels of shade matching (disks, 77.6%; tabs, 77.1%). When tabs were matched first, the scores were as follows: disks, 79.8%, and tabs, 67.3% (P=.010). Within the limitations of this study, there was no significant difference in shade-matching accuracy between the 2 shapes, although the order of design matching resulted in a difference in shade-matching ability. When tabs were matched first and disks second, improved matching was evident on the second test. The reverse

  10. Influence of P205, AgNO3, and FeCl3 on color and translucency of lithia-based glass-ceramics.

    Science.gov (United States)

    Anusavice, K J; Zhang, N Z; Moorhead, J E

    1994-07-01

    The objective of this study was to characterize the influence of various metals, metal compounds, and P2O5 as a nucleating agent on the color and translucency of a Li2O-Al2O3-CaO-SiO2 glass-ceramic. Glass frits of Li2O-Al2O3-CaO-SiO2 (LACS), LACS with 1 mol% P2O5 (LACSP), and/or LACS with one of 16 colorants were melted, poured into a cylindrical graphite mold, cut into disks, annealed, nucleated, crystallized, and annealed again. Ten translucency measurements of each of five disks were made using a tristimulus colorimeter and a D65 standard CIE illuminant. The color of each disk was analyzed using the CIE L*a*b* color space system (1976) as a function of colorant, colorant concentration, and P2O5. Mean L* values of glass-ceramic disks ranged from 63.5 for LACS containing 6.2 mmol% FeCl3 (LACSP-6.2Fe) to 84.1 for LACS. No significant difference (p > 0.05) was found between the mean L* values for LACS, LACSP, and LACS with 0.19 mmol% AgNO3 (LACS-0.19Ag). The mean contrast ratio of glass-ceramic specimens ranged from 0.42 (LACS and LACS-1.0Fe) to 0.98 (LACS-0.78Ag). Mean color difference values varied from 5.8 (LACSP-1.0Fe vs. LACS) to 36.3 (LACSP-0.78Ag vs. LACSP). The results of this study indicate that, because certain colorants in glass-ceramics affect opacity as well as hue and chroma, the development of glass-ceramics should be simplified by: 1) employing a nucleating agent that does not affect hue or chroma significantly, 2) controlling fixed levels of translucency consistent with mechanical and physical property requirements, and 3) varying the hue and chroma by means of colorants that do not affect the crystallization process. This implies that the volume fraction and mean size of crystals must be controlled, since the translucency or opacity of glass-ceramics is associated with scattering of light at the interfaces between adjacent crystals, and between crystals and the glass phase because of differences in refractive indices (McMillan, 1979a).

  11. Assessment of colorectal liver metastases using MRI and CT: Impact of observer experience on diagnostic performance and inter-observer reproducibility with histopathological correlation

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, Moritz H., E-mail: MoritzAlbrecht@gmx.net [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Wichmann, Julian L.; Müller, Cindy [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Schreckenbach, Theresa [University Hospital Frankfurt, Department of General and Visceral Surgery, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Sakthibalan, Sreekanth [Barts and the London, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Hammerstingl, Renate [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Bechstein, Wolf O. [University Hospital Frankfurt, Department of General and Visceral Surgery, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Zangos, Stephan [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Ackermann, Hanns [University Hospital Frankfurt, Department of Biostatistics and Medical Information, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Vogl, Thomas J. [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany)

    2014-10-15

    Highlights: • We investigate the impact of experience on CT and MRI reporting of colorectal liver metastases. • Diagnostic quality is significantly influenced by observer experience for both CT and MRI. • MRI is more affected by experience than CT when reporting cases of colorectal liver metastases. - Abstract: Introduction: To compare the diagnostic performance and inter-observer reproducibility of CT and MRI in detecting colorectal liver metastases (CRLM) of observers with different levels of experience. Materials and methods: Data from 51 CT and 54 MRI examinations of 105 patients with CRLM were analysed. Intraoperative and histopathological findings served as the reference standard. Analyses were performed by four observers with varying levels of experience regarding imaging of CRLM (reviewers A, B, C and D with respectively >20, >5, <1 and 0 years of experience). Per-segment sensitivity, specificity, Cohen's kappa (κ) for diagnosed segments and Intra-class Correlation Coefficients (ICC) for reported number of lesions were calculated. Results: CT sensitivity and specificity was for reviewer A 89.71%/94.41%, B 78.50%/88.37%, C 63.55%/85.58%, D 84.11%/78.60% and regarding MRI A 90.40%/95.43%, B 74.40%/90.04%, C 60.00%/85.89% and D 65.60%/75.90%. The overall inter-observer agreement was higher for CT (κ = 0.43, p < 0.001; ICC = 0.75, p < 0.001) than MRI (κ = 0.38, p < 0.001; ICC = 0.65, p < 0.001). The experienced reviewers A and B achieved better agreement for MRI (κ = 0.54, p < 0.001; ICC = 0.77, p < 0.001) than CT (κ = 0.52, p < 0.00; ICC = 0.76, p < 0.001) unlike the less experienced C and D (MRI κ = 0.38, ICC = 0.63 and CT κ = 0.41, ICC = 0.74, respectively, p < 0.001). Conclusions: The proficiency in detection of CRLM is significantly influenced by observer experience, although CT interpretation is less affected than MRI analysis.

  12. Annual report of Naka Fusion Research Establishment. From April 1,2000 to March 31, 2001

    Energy Technology Data Exchange (ETDEWEB)

    Kuriyama, Masaaki; Kizu, Kaname; Kusakawa, Fumio; Matsumoto, Hiroshi; Sakamoto, Keishi; Sengoku, Seio (eds.) [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2001-11-01

    and groove by remote handling. 8) Fusion Neutronics: Radiation detectors using single cryst

  13. Termochemical Models For Slags and Silicate Melts, Review and Perspectives

    Science.gov (United States)

    Ottonello, G.

    R.O. (1983) Contrib. Mineral. Petrol., 84, 107-145. [3] Papale P. (1997) Contrib. Mineral. Petrol., 126, 237-251. [4] Papale P. (1999) Amer. Mineral., 84, 477-492. [5] Nuccio P.M. and Paonita A. (2999) Earth Planet. Sci. Letters., 183, 499-512. [6] Berman R.G. and Brown T.H. (1984) Geochim. Cosmochim. Acta, 48, 661-678. [7] Lin P.L. and Pelton A.D. (1979) Metall. Trans. B., 10B, 667-675. [8] Pelton A.D. and Blander M. (1986) Metall. Trans. B., 17B, 805-15. [9] Kapoor M.L., Mehrotre G.M. and Frohberg M.G. (1975) Proc. Aust. Inst. Mining Metall., 254, 11. [10] Kapoor M.L., Frohberg G.M. (1971) Proc. Symp. "Chemical Metallurgy of Iron and Steel" Sheffield. [11] Taylor J.R. and Dinsdale A.T. (1990] CALPHAD, 14, 71-88. [12] Sastri P. and Lahiri A.K. (1986) Metall. Trans. B., 17B, 105-110. [13] Bjorkman B. (1985) CALPHAD, 9, 271-282. [14] Hastie J.W., Horton W.S., Plante E.R. and Bonnell D.W. (1982) High Temp. High Press., 14, 669-679. [15] Goel R.P., Kellogg H.H. and Larrain J.M. (1980) Metall. Trans. B., 11B, 107-117. [16] Hillert M., Sundman B. and Wang X. (1990) Metall. Trans. B., 21B, 303-12. [17] Hoch M. and Arpshofen I. (1984) Zeits. fur Metallkde., 75, 23-29. [18] Masson C.R. (1965) Proc. Roy. Soc. London, A287, 201-221. [19] Masson C.R. (1968) J. Amer. Ceram. Soc., 51, 134-143. [20] Masson C.R. (1972) Jour. Iron Steel Inst., 210, 89-96. [21] Toop G.W. and Samis C.S. (1962) Can. Met. Quart., 1, 129-52. [22] Toop G.W. and Samis C.S. (1962) Trans. AIME, 224, 878-87. [23] Ottonello G., Moretti R., Marini L. and Vetuschi Zuccolini M. (2000) Chem. Geol., 174, 157-179. [24] Ottonello G. (2001) J. Non-Cryst. Solids, 282, 72-85. [25] Moretti R. and Ottonello G. (2002) , Metall. Trans. (submitted).

  14. Model-Driven Development for scientific computing. Computations of RHEED intensities for a disordered surface. Part I

    Science.gov (United States)

    Daniluk, Andrzej

    2010-03-01

    separate thread inside each transaction generated by the master Growth09 program (see pii:S0010-4655(09)00386-5 A. Daniluk, Model-Driven Development for scientific computing. Computations of RHEED intensities for a disordered surface. Part II The RHEED1DProcess requires the user to provide the appropriate parameters for the crystal structure under investigation. These parameters are loaded from the parameters.ini file at run-time. Instructions on the preparation of the .ini files can be found in the new distribution. The RHEED1DProcess requires the user to provide the appropriate values of the layers of coverage profiles. The CoverageProfiles.dat file (generated by Growth09 master application) at run-time loads these values. The RHEED1DProcess enables carrying out one-dimensional dynamical calculations for the fcc lattice, with a two-atoms basis and fcc lattice, with one atom basis but yet the zeroth Fourier component of the scattering potential in the TRHEED1D::crystPotUg() function can be modified according to users' specific application requirements. * The figures mentioned can be downloaded, see "Supplementary material" below. Unusual features: The program is distributed in the form of main projects RHEED1DProcess.cbproj and Graph2D0x.cbproj with associated files, and should be compiled using Embarcadero RAD Studio 2010 along with Together visual-modelling platform. The program should be compiled with English/USA regional and language options. Additional comments: This version of the RHEED program is designed to run in conjunction with the GROWTH09 (ADVL_v3_0) program. It does not replace the previous, stand alone, RHEEDGR-09 (ADUY_v3_0) version. Running time: The typical running time is machine and user-parameters dependent. References:[1] OMG, Model Driven Architecture Guide Version 1.0.1, 2003.

  15. Model-Driven Development for scientific computing. An upgrade of the RHEEDGr program

    Science.gov (United States)

    Daniluk, Andrzej

    2009-11-01

    calculations for the fcc lattice, with a two-atoms basis and fcc lattice, with one atom basis but yet the zeroth Fourier component of the scattering potential in the TRHEED1D::crystPotUg() function can be modified according to users' specific application requirements. A graphical user interface (GUI) for the program has been reconstructed. The program has been compiled with English/USA regional and language options. Unusual features: The program is distributed in the form of main projects RHEEDGr_09.cbproj and Graph2D0x.cbproj with associated files, and should be compiled using Code Gear C++ Builder 2009 compilers. Running time: The typical running time is machine and user-parameters dependent. References: OMG, Model Driven Architecture Guide Version 1.0.1, 2003, http://www.omg.org/cgi-bin/doc?omg/03-06-01. A. Daniluk, Comput. Phys. Comm. 166 (2005) 123.

  16. EDITORIAL: Nanotechnology in vivo Nanotechnology in vivo

    Science.gov (United States)

    Demming, Anna

    2010-04-01

    of nanoparticles in the tumour vasculature. However, previous reports on techniques to generate nanobubbles have either been slow or problematic due to the resulting development of cardiac dimension reduction, hypotension and tachycardia. Xing and colleagues have now demonstrated the use of polyoxyethylene 40 stearate, which is known to be biocompatible, degradable and non-toxic, as an alternative surfactant for generating nanobubbles. In the early 1980s scanning probe micrographs of nanosized features unleashed the power of imaging to push forward the science of structures and mechanisms at the nanoscale. The continued development of new and increasingly sophisticated nanoparticles and systems looks set to empower medicine in the same way, providing further means to exploit the mechanistic nature of biological organisms for better health and longevity. References [1] Leon R, Petroff P M, Leonard D and Fafard S 1995 Science 267 1966-8 [2] Nie Q, Tan W B and Zhang Y 2006 Nanotechnology 17 140-4 [3] Li L, Chen D, Zhang Y, Deng Z, Ren X, Meng X, Tang F, Ren J and Zhang L 2007 Nanotechnology 18 405102 [4] Fujioka K et al 2008 Nanotechnology 19 415102 [5] Shinoda K, Yangisawa S, Sato K amd Hirakuri K 2006 J. Cryst. Growth 288 84-6 [6] Manzoor K, Johny S, Thomas D, Setua S, Menon D and Nair S 2009 Nanotechnology 20 065102 [7] Hu R, Yong K-T, Roy I, Ding H, Law W-C, Cai H, Zhang X, Vathy L A, Bergey E J and Prasad P N 2010 Nanotechnology 21 145105 [8] Xing, Z, Ke H, Wang J, Zhao B, Yue X, Dai Z and Liu J 2010 Nanotechnology 21 145607

  17. BARRINGER AWARD ADDRESS: Shock Metamorphism of Quartz in Nature and Experiment: A Review

    Science.gov (United States)

    Stoffler, D.

    1993-07-01

    . (1985) Phys. Chem. Mineral., 11, 241- 249. [8] Stoffler D. (1984) J. Non-Cryst. Solids, 67, 465-502, and references therein. [9] Gratz A. J. (1992) Phys. Chem. Mineral., 19, 267-288, [10] Rehfeldt-Oskierski A. (1986) Ph.D. thesis, Univ. of Munster. [11] Grothues J. (1988) Diploma thesis, Univ. of Muenster [12] Langenhorst F. (1993), Ph.D. thesis, Univ. of Munster. [13] Kieffer S. W. et al. (1976) Contr. Mineral. Petrol., 59, 41-93, [14] Langenhorst F. (1992) Nature, 356, 507-509.

  18. Interaction of host-guest complexes of cucurbit[n]urils with double probe guests

    Institute of Scientific and Technical Information of China (English)

    MA; Peihua; DONG; Jun; XIANG; Shuangchun; XUE; Saifeng; ZH

    2004-01-01

    -cucurbituril: cis-SnCl4(OH2)2 @cucurbit[7]uril, Cryst. Eng.Comm., 2001, 49: 1-7.[13]Krasia, T. C., Steinke, J. H. G., Formation of oligotriazoles catalysed by cucurbituril, Chem. Commun. (Camb.), 2002, 1: 22-23.[14]Kim, H. J., Heo, J., Jeon, W. S. et al., Selective inclusion of a hetero-guest pair in a molecular host: formation of stable charge-transfer complexes in cucurbit[8]uril, Angew. Chem. Int.Ed., 2001, 40(8): 1526-1529.[15]Burnett, C. A., Witt, D., Fettinger, J. C. et al., A cyclic congener of cucurbituril: synthesis and recognition properties, J. Org.Chem., 2003, 68(16): 6184-6191.[16]Samsonenko, D. G., Virovets, A. V., Lipkowski, J. et al., Distortion of the cucurbituril molecule by an included 4-methylpyridinum cation, J. Struc. Chem. (Translation of Zhurnal Strukturnoi Khimii), 2002, 43(4): 664-668.[17]Lim, Y. b., Kim, T., Lee, J. W. et al., Self-assembled ternary complex of cationic dendrimer, cucurbituril, and DNA: noncovalent strategy in developing a gene delivery carrier, Bioconjugate Chem., 2002, 13(6): 1181-1185.[18]Miyahara, Y., Abe, K., Inazu, T., "Molecular" molecular sieves:lid-free decamethylcucurbit[5]uril absorbs and desorbs gases selectively, Angew. Chem. Int. Ed., 2002, 41 (16): 3020-3023.[19]Tan, Y., Choi, S. W., Lee, J. W. et al., Synthesis and characterization of novel side-chain pseudopol- yrotaxanes containing cucurbituril, Macromolecules, 2002, 35(18): 7161-7165.[20]Ong, W., Gomez, K. M., Kaifer, A. E., Cucurbit[7]uril: a very effective host for viologens and their cation radicals, Org. Lett.,2002, 4(10): 1791-1794.[21]Shen, Y. Q., Xue, S. F., Zhao, Y. J. et al., NMR study on self-assembled cage complex of hexamethylenetetramine and cucurbit[n]urils, Chinese Science Bulletin, 2004, 48(1): 2694-2697.[22]Luo, X. Q., Xue, S. F., Zhu, Q. J., A new method for synthesis and separation of a new family cage compounds-cucurbit[n = 5-8]urils, J. Guizhou Univ. (Nat. Sci.), 2003, 20(1): 184-187.

  19. PREFACE: The first 21 years of reverse Monte Carlo modelling—a workshop held in Budapest, Hungary (1-3 October 2009) The first 21 years of reverse Monte Carlo modelling—a workshop held in Budapest, Hungary (1-3 October 2009)

    Science.gov (United States)

    Keen, David A.; Pusztai, László

    2010-10-01

    scientific community by showing the current state-of-the-art research opportunities using the RMC method. Furthermore, by including a small number of papers from colleagues working on similar disordered problems with complementary analysis techniques, we hope that the RMC method may be placed in a broader scientific context. The papers have been arranged in order of increasing structural disorder, starting with studies of crystalline systems, through to amorphous materials and liquids, and ending with RMC developments using small-angle scattering. We are very grateful to IOP Publishing for their willingness to publish this collection of papers which celebrates the 21st anniversary of the first RMC publication in a special issue of Journal of Physics: Condensed Matter and for their co-ordination of the refereeing process. References [1] McGreevy R L 2001 J. Phys.: Condens. Matter 13 R877 [2] Keen D A and Pusztai L (ed) 2007 Proc. of RMC-3 (Budapest, Sept. 2006) J. Phys.: Condens. Matter 19 330301-335223 [3] Keen D A, Pusztai L and Dove M T (ed) 2005 Proc. of RMC-2 (Budapest, Oct. 2003) J. Phys.: Condens. Matter 17 S1-S174 [4] Nguyen T X, Cohaut N, Bae J-S and Bhatia S K 2008 Langmuir 24 7912 [5] Zhang H, Chen B and Banfield J F 2008 Phys. Rev. B 78 214106 [6] Goodwin A L, Calleja M, Conterio M J, Dove M T, Evans J S O, Keen D A, Peters L and Tucker M G 2008 Science 319 794 [7] Norberg S T, Tucker M G and Hull S 2009 J. Appl. Cryst. 42 179 [8] See www.RMCProfile.org, www.RMC-forum.org or www.szfki.hu/~nphys/rmc++/opening.html [9] Haines J, Levelut C, Isambert A, Hébert P, Kohara S, Keen D A, Hammouda T and Andrault D 2009 J. Am. Chem. Soc. 131 12333

  20. Dental shade guide colour values research under a new LED light%新型LED比色光源下口腔比色板色度值研究

    Institute of Scientific and Technical Information of China (English)

    宋洁文; 姚科; 邱颖宁; 李彦

    2014-01-01

    目的研究自制白光发光二极管(LED)矩阵光源光学参数及其对口腔比色版的色度值影响,为研发便携式LED口腔比色光源提供数据参考。方法采用波长主峰为450~470 nm单晶GaN蓝光LED矩阵,在其表面涂覆稀土钇铝石榴石(YAG)荧光粉并使用一定比例硅酸盐红色荧光粉调节色温的方法制作色温接近5500 K的连续光谱白光光源。使用4π结构积分球测试LED光源光学指数并了解其与D55标准照明体的拟合程度。并将此光源与人工日光D65标准光源作对照,观察二者对各3块口腔常用Vita 3D Master和Vita Classia比色板CIE L*、a*、b*色度值的影响,并用ΔE*94值对差别进行比较。结果自制白光LED光源光通量φ=389.90 lm,色品坐标x=0.3342、y=0.3335,色温Tc=5453 K,主波长λd=600.2 nm,峰值波长λp=455.0 nm,半宽度Δλp=25.6 nm,显色指数Ra=95.3。3块VITA 3D Master和VITA Classial 上同一色标L*、a*、b*均值在同一光源下两两比较差异无统计学意义(P>0.05)。不同光源下VITA 3D Master和VITA Classial各色标间色差ΔE*94均值分别为1.58和0.96 NBS。结论自制白光LED矩阵光源达到D55标准照明体的色温和显色指数要求,能作为重组日光光源以替代自然日光应用于口腔临床。%Objective Optical parameters of a self-developed white Light-Emitting Diode (LED) array are measured to understand their impacts on colour values of shade guide for dental application . It is to provide data reference for portable LED shade guide light source . Methods White light source with continuous spectrum having 5500 K colour temperature is maded by coating yttrium aluminate garnet (YAG) on the surface of GaN LED array, which has emission wavelength at 450~470 nm range, and using certain percentage red phosphor silicate for colour temperature tuning . Optical parameters of such LED are measured by an integrating sphere with 4