The Experts below are selected from a list of 1560 Experts worldwide ranked by ideXlab platform
Robson F. De Farias - One of the best experts on this subject based on the ideXlab platform.
-
solid state synthesis characterization and thermogravimetric study of the adducts cocl2 6l l ethyleneurea propyleneurea and Ethylenethiourea
Thermochimica Acta, 2001Co-Authors: Robson F. De FariasAbstract:Abstract The title compounds were synthesized by using an alternative solid state route, and characterized by elemental analysis, infrared spectroscopy and thermogravimetry. The IR data are in agreement with a coordination through oxygen for ethyleneurea (EU) and propyleneurea (PU) and through nitrogen for Ethylenethiourea (ETU). EU, PU and ETU adducts exhibit two mass loss steps, suggesting that the coordination positions are not equivalent for all adducts, and that there are two ligand molecules closer to the metal cation. This hypothesis is supported by quantum chemical (density functional, DF) calculations. The observed thermal stability sequence is ETU>PU>EU.
-
Synthesis, characterization and thermal behavior of 18 cadmium halides adducts involving ethyleneurea, Ethylenethiourea and propyleneurea
Thermochimica Acta, 2001Co-Authors: Robson F. De Farias, Leandro Martínez, Claudio AiroldiAbstract:Abstract In this work we report on the synthesis, characterization and thermal behavior of 18 adducts of general formula CdX 2 · n L (where X=Cl, Br and I, n =1 and 2, and L=ethyleneurea (eu), Ethylenethiourea (etu) and propyleneurea (pu)). The IR spectroscopy results shows that for the eu and pu adducts, coordination occurs through oxygen, whereas for etu, nitrogen is used as coordination site. The thermogravimetric curves shows that the synthesized adducts releases the ligand molecules in a single mass loss step. In considering adducts with same stoichiometry, the observed thermal stability trend is etu>pu>eu.
-
Solid state synthesis, characterization and thermogravimetric study of the adducts CoCl2.6L (L = ethyleneurea, propyleneurea and Ethylenethiourea)
Thermochimica Acta, 2001Co-Authors: Robson F. De FariasAbstract:Abstract The title compounds were synthesized by using an alternative solid state route, and characterized by elemental analysis, infrared spectroscopy and thermogravimetry. The IR data are in agreement with a coordination through oxygen for ethyleneurea (EU) and propyleneurea (PU) and through nitrogen for Ethylenethiourea (ETU). EU, PU and ETU adducts exhibit two mass loss steps, suggesting that the coordination positions are not equivalent for all adducts, and that there are two ligand molecules closer to the metal cation. This hypothesis is supported by quantum chemical (density functional, DF) calculations. The observed thermal stability sequence is ETU>PU>EU.
Atsushi Takahashi - One of the best experts on this subject based on the ideXlab platform.
-
Species differences between rats and mice in the teratogenic action of Ethylenethiourea: In vivo/in vitro tests and teratogenic activity of sera using an embryonic cell differentiation system
Toxicology and applied pharmacology, 1991Co-Authors: Toshie Tsuchiya, Akitada Nakamura, Toshihiro Iio, Atsushi TakahashiAbstract:In vivo/in vitro studies on rats showed that Ethylenethiourea inhibited the differentiation of midbrain cells more severely than that of limb bud cells. In in vitro studies using midbrain cell cultures, Ethylenethiourea concentrations inhibited the production of differentiated foci by 50% in mouse cells, a rate 11-fold higher than that in rat cells. Differentiation of rat midbrain cells was also inhibited by the serum samples prepared from rats or mice dosed with up to 200 mg/kg of Ethylenethiourea. However, differentiation of mouse cells was not inhibited by these animal serum samples. The concentration of Ethylenethiourea in rat sera was only 2-fold higher than that in mice sera at 2 hr after dosing with 200 mg/kg. Therefore, the different sensitivity of the midbrains of these two species may be one reason that Ethylenethiourea is teratogenic in rats but not in mice.
-
species differences between rats and mice in the teratogenic action of Ethylenethiourea in vivo in vitro tests and teratogenic activity of sera using an embryonic cell differentiation system
Toxicology and Applied Pharmacology, 1991Co-Authors: Toshie Tsuchiya, Akitada Nakamura, Toshihiro Iio, Atsushi TakahashiAbstract:In vivo/in vitro studies on rats showed that Ethylenethiourea inhibited the differentiation of midbrain cells more severely than that of limb bud cells. In in vitro studies using midbrain cell cultures, Ethylenethiourea concentrations inhibited the production of differentiated foci by 50% in mouse cells, a rate 11-fold higher than that in rat cells. Differentiation of rat midbrain cells was also inhibited by the serum samples prepared from rats or mice dosed with up to 200 mg/kg of Ethylenethiourea. However, differentiation of mouse cells was not inhibited by these animal serum samples. The concentration of Ethylenethiourea in rat sera was only 2-fold higher than that in mice sera at 2 hr after dosing with 200 mg/kg. Therefore, the different sensitivity of the midbrains of these two species may be one reason that Ethylenethiourea is teratogenic in rats but not in mice.
Toshie Tsuchiya - One of the best experts on this subject based on the ideXlab platform.
-
Species differences between rats and mice in the teratogenic action of Ethylenethiourea: In vivo/in vitro tests and teratogenic activity of sera using an embryonic cell differentiation system
Toxicology and applied pharmacology, 1991Co-Authors: Toshie Tsuchiya, Akitada Nakamura, Toshihiro Iio, Atsushi TakahashiAbstract:In vivo/in vitro studies on rats showed that Ethylenethiourea inhibited the differentiation of midbrain cells more severely than that of limb bud cells. In in vitro studies using midbrain cell cultures, Ethylenethiourea concentrations inhibited the production of differentiated foci by 50% in mouse cells, a rate 11-fold higher than that in rat cells. Differentiation of rat midbrain cells was also inhibited by the serum samples prepared from rats or mice dosed with up to 200 mg/kg of Ethylenethiourea. However, differentiation of mouse cells was not inhibited by these animal serum samples. The concentration of Ethylenethiourea in rat sera was only 2-fold higher than that in mice sera at 2 hr after dosing with 200 mg/kg. Therefore, the different sensitivity of the midbrains of these two species may be one reason that Ethylenethiourea is teratogenic in rats but not in mice.
-
species differences between rats and mice in the teratogenic action of Ethylenethiourea in vivo in vitro tests and teratogenic activity of sera using an embryonic cell differentiation system
Toxicology and Applied Pharmacology, 1991Co-Authors: Toshie Tsuchiya, Akitada Nakamura, Toshihiro Iio, Atsushi TakahashiAbstract:In vivo/in vitro studies on rats showed that Ethylenethiourea inhibited the differentiation of midbrain cells more severely than that of limb bud cells. In in vitro studies using midbrain cell cultures, Ethylenethiourea concentrations inhibited the production of differentiated foci by 50% in mouse cells, a rate 11-fold higher than that in rat cells. Differentiation of rat midbrain cells was also inhibited by the serum samples prepared from rats or mice dosed with up to 200 mg/kg of Ethylenethiourea. However, differentiation of mouse cells was not inhibited by these animal serum samples. The concentration of Ethylenethiourea in rat sera was only 2-fold higher than that in mice sera at 2 hr after dosing with 200 mg/kg. Therefore, the different sensitivity of the midbrains of these two species may be one reason that Ethylenethiourea is teratogenic in rats but not in mice.
Daniel R. Doerge - One of the best experts on this subject based on the ideXlab platform.
-
Liquid chromatographic determination of Ethylenethiourea using pulsed amperometric detection.
Journal of chromatography, 1991Co-Authors: Daniel R. Doerge, Austin B. K. YeeAbstract:Abstract A liquid chromatographic method was developed using pulsed amperometric detection at a gold working electrode to measure residue levels of Ethylenethiourea (ETU) in crops and groundwater. Use of the sequential pulsing program eliminates electrode fouling while preserving the sensitive and selective detection of ETU. Minimum detection limits in crops were 5–10 ppb (1.25–2.5 ng on-column) and 5 ppb (0.5 ng) in groundwater. The commercial availability of the pulsed electrochemical detector and its gold working electrode that remains functional with a minimum of conditioning is an improvement in method simplicity.
-
Fate of Ethylenethiourea in Hawaiian soil and water
Journal of Agricultural and Food Chemistry, 1991Co-Authors: Carl J. Miles, Daniel R. DoergeAbstract:Ethylenethiourea (ETU) is rapidly degraded and detoxified to ethyleneurea (EU) and sulfate ion in the soils studied by chemical oxidation, possibly by hydroxyl radicals. EU is further degraded by soil microorganisms to ethylenediamine and CO 2 . ETU degraded very slowly in groundwater, but the rate increased significantly with addition of basalt. ETU should not reach deep groundwater because of rapid breakdown in overlying soils
-
synthesis of isotopically labelled Ethylenethiourea
Journal of Labelled Compounds and Radiopharmaceuticals, 1990Co-Authors: Daniel R. Doerge, Niranjala M. Cooray, Austin B. K. Yee, Walter P. NiemczuraAbstract:13C-, 14C- and 15N-labelled Ethylenethiourea was synthesized for NMR and radiotracer applications in metabolism and environmental fate studies. The products contained stable isotopes at 99% enrichment and the radiolabelled product had specific activity of 2.0 mCi/mmole.
-
Synthesis of isotopically‐labelled Ethylenethiourea
Journal of Labelled Compounds and Radiopharmaceuticals, 1990Co-Authors: Daniel R. Doerge, Niranjala M. Cooray, Austin B. K. Yee, Walter P. NiemczuraAbstract:13C-, 14C- and 15N-labelled Ethylenethiourea was synthesized for NMR and radiotracer applications in metabolism and environmental fate studies. The products contained stable isotopes at 99% enrichment and the radiolabelled product had specific activity of 2.0 mCi/mmole.
-
Mechanism of thyroid peroxidase inhibition by Ethylenethiourea.
Chemical research in toxicology, 1990Co-Authors: Daniel R. Doerge, Richard S. TakazawaAbstract:Ethylenethiourea (ETU) is a thyroid carcinogen present in foods formed by degradation and metabolism of ethylenebis[dithiocarbamate] fungicides. ETU inhibits thyroid peroxidase (TPX), the enzyme that catalyzes synthesis of thyroid hormones. Inhibition of TPX-catalyzed reactions by ETU occurs only in the presence of iodide ion with concomitant oxidative metabolism to imidazoline and bisulfite ion. Inhibition ceases upon consumption of ETU with no loss of enzymatic activity and negligible covalent binding of ETU to TPX. TPX inhibition by ETU is unlike that for derivatives of imidazoline-2-thione, which cause suicide inactivation via covalent binding to the prosthetic heme group. These results demonstrate a metabolic route for detoxication of ETU in the thyroid and suggest that low-level or intermittent exposure to ETU would have minimal effects on thyroid hormone production.
Claudio Airoldi - One of the best experts on this subject based on the ideXlab platform.
-
molybdenum v germanium iv aluminum iii and nickel ii adducts with ethyleneurea Ethylenethiourea and propyleneurea some empirical correlations involving tg and ir data
Journal of The Serbian Chemical Society, 2006Co-Authors: Claudio AiroldiAbstract:The adducts MoCl 5 ·2eu, MoCl 5 ·2pu, GeCl 4 ·2etu, AlCl 3 ·2pu, AlCl 3 ·3pu, NiCl 2 ·2etu and NiCl 2 ·4etu (eu = ethyleneurea, etu = Ethylenethiourea and pu = propyleneurea) were synthesized and characterized by elemental analysis (C, H, N), infrared spectroscopy (IR) and thermogravimetry (TG). IR Results show that eu and pu coordinate through oxygen, whereas etu coordinates through nitrogen. For all investigated adducts, a single mass loss step associated with the release of ligand molecules is observed. Empirical correlations involving TG and IR data are established.
-
Synthesis, characterization and thermal behavior of 18 cadmium halides adducts involving ethyleneurea, Ethylenethiourea and propyleneurea
Thermochimica Acta, 2001Co-Authors: Robson F. De Farias, Leandro Martínez, Claudio AiroldiAbstract:Abstract In this work we report on the synthesis, characterization and thermal behavior of 18 adducts of general formula CdX 2 · n L (where X=Cl, Br and I, n =1 and 2, and L=ethyleneurea (eu), Ethylenethiourea (etu) and propyleneurea (pu)). The IR spectroscopy results shows that for the eu and pu adducts, coordination occurs through oxygen, whereas for etu, nitrogen is used as coordination site. The thermogravimetric curves shows that the synthesized adducts releases the ligand molecules in a single mass loss step. In considering adducts with same stoichiometry, the observed thermal stability trend is etu>pu>eu.