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QC 20201215

QC 20191202

QC 20151216

QC 20151216

BACKGROUND: Results from several cohort and case-control studies suggest a protective association between current alcohol intake and risk of thyroid carcinoma, but the epidemiological evidence is not completely consistent and several questions remain unanswered. METHODS: The association between alcohol consumption at recruitment and over the lifetime and risk of differentiated thyroid carcinoma was examined in the European Prospective Investigation into Cancer and Nutrition. Among 477 263 eligible participants (70% women), 556 (90% women) were diagnosed with differentiated thyroid carcinoma over a mean follow-up of 11 years. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multivariable Cox proportional hazards models. RESULTS: Compared with participants consuming 0.1-4.9 g of alcohol per day at recruitment, participants consuming 15 or more grams (approximately 1-1.5 drinks) had a 23% lower risk of differentiated thyroid carcinoma (HR=0.77; 95% CI=0.60-0.98). These findings did not differ greatly when analyses were conducted for lifetime alcohol consumption, although the risk estimates were attenuated and not statistically significant anymore. Similar results were observed by type of alcoholic beverage, by differentiated thyroid carcinoma histology or according to age, sex, smoking status, body mass index and diabetes. CONCLUSIONS: Our study provides some support to the hypothesis that moderate alcohol consumption may be associated with a lower risk of papillary and follicular thyroid carcinomas.

QC 20150326. QC 20160212

QC 20131127

Lipid content of planula larvae of the brooding scleractinian coral Favia fragum was analysed through a monthly planulation period. The average lipid content per dry weight of F. fragum planulae was 39%, which is low compared with other scleractinian coral species. Lipid content of planulae was significantly affected by the day of release and decreased during the planulation period., authorCount :2

Liquid ammonia, trialkyl phosphites, and especially trialkylphosphines, are very powerful electron-pair donor solvents with soft bonding character. The solvent molecules act as strongly coordinating ligands towards mercury(ii), interacting strongly enough to displace halide ligands. In liquid ammonia mercury(ii) chloride solutions separate into two liquid phases, the upper contains tetraamminemercury(ii) complexes, [Hg(NH3)4] 2+, and chloride ions in low concentration, while the lower is a dense highly concentrated solution of [Hg(NH3)4] 2+ entities, ca. 1.4 mol dm-3, probably ion-paired by hydrogen bonds to the chloride ions. Mercury(ii) bromide also dissociates to ionic complexes in liquid ammonia and forms a homogeneous solution for which 199Hg NMR indicates weak bromide association with mercury(ii). When dissolving mercury(ii) iodide in liquid ammonia and triethyl phosphite solvated molecular complexes form in the solutions. The Raman ?(I-Hg-I) symmetric stretching frequency is 132 cm-1 for the pseudo-tetrahedral [HgI 2(NH3)2] complex formed in liquid ammonia, corresponding to DS = 56 on the donor strength scale. For the Hg(ClO4)2/NH4I system in liquid ammonia a 199Hg NMR study showed [HgI4]2- to be the dominating mercury(ii) complex for mole ratios n(I-): n(Hg 2+) 6. A large angle X-ray scattering (LAXS) study of mercury(ii) iodide in triethyl phosphite solution showed a [HgI2(P(OC 4H9)3)2] complex with the Hg-I and Hg-P bond distances 2.750(3) and 2.457(4) Å, respectively, in near tetrahedral configuration. Trialkylphosphines generally form very strong bonds to mercury(ii), dissociating all mercury(ii) halides. Mercury(ii) chloride and bromide form solid solvated mercury(ii) halide salts when treated with tri-n-butylphosphine, because of the low permittivity of the solvent. A LAXS study of a melt of mercury(ii) iodide in tri-n-butylphosphine at 330 K resulted in the Hg-I and Hg-P distances 2.851(3) and 2.468(4) Å, respectively. The absence of a distinct I-I di

The ammonia solvated mercury(II) ion has been structurally characterized in solution by means of EXAFS, 199Hg NMR, and Raman spectroscopy and in solid solvates by combining results from X-ray single crystal and powder diffraction, thermogravimetry, differential scanning calorimetry, EXAFS, and Raman spectroscopy. Crystalline tetraamminemercury(II) perchlorate, [Hg(NH 3)4](ClO4)2, precipitates from both liquid ammonia and aqueous ammonia solution, containing tetraamminemercury(II) complexes. The orthorhombic space group (Pnma) imposes Cs symmetry on the tetraamminemercury(II) complexes, which is lost at a phase transition at about 220 K. The Hg-N bond distances are 2.175(14), 2.255(16), and 2 x 2.277(9) Å, with a wide N-Hg-N angle between the two shortest Hg-N bonds, 122.1(7)°, at ambient temperature. A similar distorted tetrahedral coordination geometry is maintained in liquid ammonia and aqueous ammonia solutions with the mean Hg-N bond distances 2.225(12) and 2.226(6) Å, respectively. When heated to 400 K the solid tetraamminemercury(II) Perchlorate decomposes to diamminemercury(II) Perchlorate, [Hg(NH3) 2](ClO4)2, with the mean Hg-N bond distance 2.055(6) Å in a linear N-Hg-N unit. The mercury atoms in the latter compound form a tetrahedral network, connected by perchlorate oxygen atoms, with the closest Hg?Hg distance being 3.420(3) Å. The preferential solvation and coordination changes of the mercury(II) ion in aqueous ammonia, by varying the total NH3:Hg(II) mole ratio from 0 to 130, were followed by 199Hg NMR. Solid [Hg(NH3)4](ClO 4)2 precipitates while [Hg(H2O) 6]2+ ions remain in solution at mole ratios below 3-4, while at high mole ratios, [Hg(NH3)4]2+ complexes dominate in solution. The principal bands in the vibrational spectrum of the [Hg(NH3)4]2+ complex have been assigned. © 2008 American Chemical Society.

Crystals of the title compound, calcium dipotassium diphosphate, have been synthesized from a melt and structurally characterized using single-crystal X-ray diffraction. The CaK2P2O7 structure can be described as a layer structure, with alternating [K2P2O72-](infinity) and [Ca2+](infinity) layers parallel to the ab plane. Ca2+ is coordinated by six O atoms in a distorted octahedron. K+ is coordinated by nine O atoms in two different polyhedra., QC 20100525

The Structures of the dimeric bispentacyanoplatinate (III) (Pt-Pt) complex [Pt-2(CN)(10)](4-) and the pentacyanoplatinuni(IV) species [Pt(CN)(5)(OH)](2-), [Pt(CN)(5)(H2O)](-), and [Pt(CN)(5)I](2-) have been studied in aqueous solution by the EXAFS technique. A nonsupported Pt-Pt bond, 2.73(l) Angstrom, connects two Pt(CN)(5) entities in the dimer. Normal coordinate analyses have been made on the basis of the Raman spectra, and the force constants have been used for discussions of the bonding. The metal-metal stretching force constants for the [Pt-2(CN)(10)](4-) Complex, the [(NC)(5)Pt-TI(CN)(n)](n-) (n = 1, 2, and 3) complexes, and some other dimetallic complexes have been correlated with the metal-metal bond distances. In the [Pt(CN)(5)X](n-) complexes, the mean Pt-C bond distance of the pentacyanoplatinum group was found to increase, and the corresponding Pt-C force constants were found to decrease, with increasing donor ability of the ligand X in the order X = H2O, OH, I, and Pt(CN)(5). The crystal structures of the compounds Tl-2[Pt(CN)(5)(OH)] and K-2[Pt(CN)(5)I].0.6H(2)O were determined by single-crystal X-ray diffraction techniques and used for comparisons with the EXAFS models. The Pt-I bond distance of the [Pt(CN)(5)I](2)- complex is 2.676(2) Angstrom in the crystal structure and 2.66(1) Angstrom in solution by EXAFS. A method is described for estimating the force constant for the metal-metal bond stretch in dimetallic complexes with heavy metal atoms, based on the use of an effective spectroscopic mass of the metal atoms in a diatomic model. The 18-electron rule is found to be useful for rationalizing the structures of the metal-metal bonded cyano complexes and a guideline in searching for metal cyano complexes analogous to those currently described., QC 20100525

EXAFS studies of metal ions with hydration numbers higher than six in aqueous solution, often show asymmetric distribution of the metal-oxygen bond distances. The hydration number can be determined from a correlation with the bond distance. The mean Ca-O distance 2.46(1) Angstrom shows the calcium( II) ion to be eight-hydrated in a wide asymmetric distribution. Theoretically calculated EXAFS oscillations for individual snapshots from an MD simulation show large variations. The scandium( III) ion is surrounded by two groups of about eight water molecules, with the mean Sc-O distance 2.185(6) Angstrom. The yttrium( III) ion coordinates eight waters in an asymmetric distribution at 2.368(5) Angstrom, and the lanthanum( III) ion 6 + 3 water molecules at 2.52(2) and 2.65(3) Angstrom, respectively. For the the uranium( IV) and thorium(IV) ions, the M-O distances 2.42(1) and 2.45(1) Angstrom, respectively, indicate hydration numbers close to 10., QC 20100525

The crystal and molecular structure of a polycrystalline powder with a metal-metal bond and the composition TlPt(CN)(5) has been determined by combining results from X-ray powder diffraction (XRD), extended X-ray absorption fine structure (EXAFS) and vibrational spectroscopic studies. The XRD data gave the tetragonal space group P4/nmm (No. 129). with a = 7.647(3), c = 8.049(3) Angstrom, Z = 2, and well-determined positions of the heavy metal atoms. The Pt-Tl bond length in the compound is 2.627(2) Angstrom. The platinum atom coordinates four equivalent equatorial cyano ligands, with a fifth axial CN ligand and a thallium atom completing a distorted octahedral coordination geometry. The Tl-Pt(CN)(5) entities are linked together in linear -NC-Pt-Tl-NC-Pt-Tl chains through the axial cyano ligand. These linear wires are the essential structural features and influence the properties of the com-pound. A three-dimensional network is formed by the four equatorial cyano ligands of the platinum atom that form bridges to the thallium atoms of neighbouring antiparallel chains. The platinum atom and the five nitrogen atoms from the bridging cyano groups form a distorted octahedron around the thallium atom. EXAFS data were recorded at the Pt and Tl L-III edges for a more complete description of the local structure around the Pt and Tl atoms. The excessive multiple scattering was evaluated by means of the FEFF program. Raman and infrared absorption spectroscopy reveal strong coupling of the vibrational modes of the TlPt(CN)(5) entities, in particular the metal - metal stretching mode, which is split into four Raman and two IR bands. Factor group theory shows that a structural unit larger than the crystallographic unit cell must be used to assign vibrational bands. Intra- and intermolecular force constants have also been calculated. The compound exhibits red luminescence at 700+/- 3 nm in glycerol and has a corresponding excitation maximum at 240 nm. X-ray photoelectron spectra (X, QC 20100525

The structure of the hydrated calcium(II) ion in aqueous solution has been studied by means of extended X-ray absorption fine structure spectroscopy (EXAFS), large-angle X-ray scattering (LAXS), and molecular dynamics (MD) methods. The EXAFS data displayed a broad and asymmetric distribution of the Ca-O bond distances with the centroid at 2.46(2) Angstrom. LAXS studies on four aqueous calcium halide solutions (1.5-2 mol dm(-3)) gave a mean Ca-O bond distance of 2.46(1) Angstrom. This is consistent with a hydration number of 8 determined from correlations between mean distances and coordination numbers from crystal structures. The LAXS studies showed a second coordination sphere with a mean Ca . . .O-II distance of 4.58(5) Angstrom, and for the hydrated halide ions the distances Cl . . .O 3.25(1) Angstrom. Br . . .O 3.36(1) Angstrom, and I . .O 3.61(1) Angstrom were obtained. Molecular dynamics simulations of CaCl2(aq) were performed using three different Ca2+-OH2 pair potentials. The potential from the GROMOS program gave results in agreement with experiments, i.e., a coordination number of 8 and an average Ca-O distance of 2.46 Angstrom, and was used for further comparisons. Theoretical EXAFS oscillations were computed far individual Mn snapshots and showed very large variations, though the simulated average spectrum from 2000 snapshots gave satisfactory agreement with the experimental EXAFS spectra. The effect of thermal motions of the coordinated atoms is inherent in the MD simulation method. Thermal disorder parameters evaluated from simulated spatial atom distribution functions of the oxygen atoms coordinated to the calcium ion were in close agreement with those from the current LAXS and EXAFS analyses. The combined results are consistent with a root-mean-square displacement from the mean Ca-O distance of 0.09(2) Angstrom in aqueous solution at 300 K., QC 20100525

The structures of three closely related heterodimetallic cyano complexes, [(NC)(5)Pt-Tl(CN)(n)](n-) (n = 1-3), formed in reactions between [Pt-II(CN)(4)](2-) and Tl-III cyano complexes, have been studied in aqueous solution. Multinuclear NMR data ((TI)-T-205, Pt-195, and C-13) were used for identification and quantitative analysis. X-ray absorption spectra were recorded at the Pt and TlLIII edges. The EXAFS data show, after developing a model describing the extensive multiple scattering within the linearly coordinated cyano ligands, short Pt-Tl bond distances in the [(NC)(5)Pt-Tl(CN)(n)](n-) complexes: 2.60(1), 2.62(1), and 2.64(1) Angstrom for n = 1-3, respectively. Thus, the Pt-Tl bond distance increases with increasing number of cyano ligands on the thallium atom. In all three complexes the thallium atom and five cyano ligands, with a mean Pt-C distance of 2.00-2.01 Angstrom, octahedrally coordinate the platinum atom. In the hydrated [(NC)(5)Pt-Tl(CN)(H2O)(4)](-) species the thallium atom coordinates one cyano ligand, probably as a linear Pt-TI-CN entity with a Tl-C bond distance of 2.13(1) Angstrom, and possibly four loosely bound water molecules with a mean Tl-O bond distance of about 2.51 Angstrom. In the [(NC)(5)Pt-Tl(CN)(2)](2-) species, the thallium atom probably coordinates the cyano ligands trigonally with two TI-C bond distances at 2.20(2) Angstrom, and in [(NC)(5)Pt-Tl(CN)(3)]Tl3- coordinates tetrahedrally with three TI-C distances at 2.22(2) Angstrom. EXAFS data were reevaluated for previously studied mononuclear thallium(III)-cyano complexes in aqueous solution, [Tl(CN)(2)(H2O)(4)](+), [Tl(CN)(3)(H2O)], and [Tl(CN)(4)](-), and also for the solid K[TI(CN)(4)] compound. A comparison shows that the TI-C bond distances are longer in the dinuclear complexes [(NC)(5)Pt-TI(CN)(n)](n-) (it = 1-3) for the same coordination number. Relative oxidation states of the metal atoms were estimated from their Pt-195 and (TI)-T-205 chemical shifts, confirming that the I, QC 20100525

The structure and vibrational spectra of the dimethyl sulfoxide solvated thallium(III) ion have been studied in a dimethyl sulfoxide solution and in the solid state. X-ray crystallography shows a trigonal unit cell, space group R (3) over bar (No. 148), for the [TI(dmso)(6)](ClO4)(3) Compound with Z = 3, a = b = 11.9764(13) [11.8995(9)] Angstrom, c = 20.802(2) [20.467(2)] Angstrom, and V = 2584.0(5) [2509.9(4)] Angstrom (3) at 295 [150] K. The crystal structure comprises a highly symmetric hexakis(dimethyl sulfoxide)thallium(III) ion, with thallium in a 3 symmetry site and a TI-O bond distance of 2.224(3) Angstrom at 295 K. The octahedral TlO6 kernel is compressed along the threefold axis with an O-Tl-O bond angle of 96.20(11)degrees. The Tl-O-S bond angle of 120.7(2)degrees corresponds to a Tl . . .S distance of 3.292(2) Angstrom. One perchlorate ion centered on the (3) over bar axis was described by a statistically disordered model. A low-temperature EXAFS study (10 K) resulted in the TI-O and Tl . . .S distances of 2.221(4) and 3.282(6) Angstrom, respectively, consistent with a Tl-O-S bond angle of 120(1)degrees. The low Debye-Waller factors confirm a regular coordination without the disorder of the dimethyl sulfoxide ligands, which would have resulted from the alternative choice of space group R3 for the crystal structure. Raman and infrared spectra have been recorded and assigned, with the bands at 435 and 447 cm(-1) corresponding to the vibrational frequency of the symmetric and asymmetric TI-O stretching modes, respectively. EXAFS data of a 0.5 mol dm(-3) thallium(III) trifluoromethanesulfonate in a dimethyl sulfoxide solution were consistent with that of a hexasolvated ion with mean Tl-O and Tl . . .S distances of 2.22(1) and 3.33(2) Angstrom, respectively, which correspond to a mean Tl-O-S bond angle of 124(2)degrees. The anomalously large disorder parameter for the TI-O distances is consistent with a weal, pseudo-Jahn-Teller effect. The Tl-205, C-13, and H, QC 20100525

Theoretical extended X-ray absorption fine structure (EXAFS) spectra have been computed from molecular dynamics (MD) simulation data. Based on MD-generated molecular geometries, EXAFS spectra were generated with the FEFF6 program, commonly used in the analysis of experimental EXAFS spectra. The effects of multiple scattering and second-shell neighbors on the theoretical spectra were evaluated for CaCl2(aq) and AlCl3(aq), i.e., for two solutions with very different cation hydration structures. The effects are significantly larger for the more structured Al3+ solution, The theoretical Ca2+(aq) spectra are compared with new experimental EXAFS data., QC 20100525