Base de dados : MEDLINE
Pesquisa : D01.930 [Categoria DeCS]
Referências encontradas : 39 [refinar]
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[PMID]:27628177
[Au] Autor:Frenvik JO; Dyrstad K; Kristensen S; Ryan OB
[Ad] Endereço:a Technology Development, Bayer AS , Lysaker , Oslo , Norway.
[Ti] Título:Development of separation technology for the removal of radium-223 from targeted thorium conjugate formulations. Part I: purification of decayed thorium-227 on cation exchange columns.
[So] Source:Drug Dev Ind Pharm;43(2):225-233, 2017 Feb.
[Is] ISSN:1520-5762
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Targeted thorium conjugates (TTCs) are being explored as a potential future platform for specific tumor targeting pharmaceuticals. In TTCs, the alpha emitting radionuclide thorium-227 ( Th) with a half-life of 18.697 d is labeled to targeting moieties, such as monoclonal antibodies (mAbs). The amount of daughter nuclide radium-223 ( Ra, t = 11.435 d) will increase during manufacture and distribution, and so a technology for purification is required to assure an acceptable level of Ra is administrated to the patient. Since Ra is the only progeny of Th with a long half-life (days), the progenies of Ra will have a very limited stay in the formulation once Ra is removed. The focus in this study has, therefore, been on the removal of Ra. In this study, the sorption and separation of Ra (radium(II)) and Th (thorium(IV)) on cation exchange columns has been evaluated as a purification method of decayed Th (i.e. prior to radiolabelling of a mAb and formation of TTC). The goal is to minimize the sorption of Th and maximize the sorption of Ra. Statistical experimental design with formulation and process parameters, including buffered formulations comprising citrate and acetate, at various concentrations and pH, presence of free radical scavenger and chelator, and resin amount have been evaluated for impact on the purification process. The studies have been interpreted by the aid of multivariate data analysis. The correlations between design of experimental variables and sorption are summarized by regression models. The predictive accuracy of radionuclide sorption was given by standard deviation and 95% confidence intervals originating from statistical cross validation. Experimental results and statistical models for citrate-buffered formulations verified reproducible and acceptable sorption levels of Ra and Th under selected conditions. For acetate-buffered formulations, prediction of Th sorption was influenced by complex variable relationships and hence a risk of obtaining irreproducibility. Fine-tuned variable levels showed, however, variable combinations predicting high sorption of Ra (>90%) and low sorption of Th (<3%) also for the acetate-buffered formulations. The optimal separation conditions should be decided based on tuning the variables levels for Ra in the citrate-buffered formulations, while for acetate, the optimal separation should be based on tuning variable levels for Th sorption. The ionic strength of the formulation also seemed to affect the radionuclide sorption. Labeling of an antibody-chelator conjugate with purified Th (i.e. preparation of TTC) was successful in the selected citrate-buffered formulations tested.
[Mh] Termos MeSH primário: Cátions/química
Radioisótopos/química
Compostos Radiofarmacêuticos/química
Rádio (Elemento)/química
Compostos de Tório/química
Tório/química
[Mh] Termos MeSH secundário: Adsorção
Meia-Vida
Concentração de Íons de Hidrogênio
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Cations); 0 (Radioisotopes); 0 (Radiopharmaceuticals); 0 (Thorium Compounds); 60YU5MIG9W (Thorium); W90AYD6R3Q (Radium)
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170630
[Lr] Data última revisão:
170630
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160916
[St] Status:MEDLINE
[do] DOI:10.1080/03639045.2016.1234484


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[PMID]:26198355
[Au] Autor:Fan QH; Zhao XL; Ma XX; Yang YB; Wu WS; Zheng GD; Wang DL
[Ad] Endereço:Key Laboratory of Petroleum Resources, Gansu Province / Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, China. fanqiaohui@gmail.com fanqh@lzb.ac.cn.
[Ti] Título:Comparative adsorption of Eu(III) and Am(III) on TPD.
[So] Source:Environ Sci Process Impacts;17(9):1634-40, 2015 Sep.
[Is] ISSN:2050-7895
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Comparative adsorption behaviors of Eu(III) and Am(III) on thorium phosphate diphosphate (TPD), i.e., Th4(PO4)4P2O7, have been studied using a batch approach and surface complexation model (SCM) in this study. The results showed that Eu(III) and Am(III) adsorption increased to a large extent with the increase in TPD dose. Strong pH-dependence was observed in both Eu(III) and Am(III) adsorption processes, suggesting that inner-sphere complexes (ISCs) were possibly responsible for the adsorption of Eu(III) and Am(III). Meanwhile, the adsorption of Eu(III) and Am(III) decreased to a different extent with the increase in ion strength, which was possibly related to outer-sphere complexes and/or ion exchange. In the presence of fulvic acid (FA), the adsorption of Eu(III) and Am(III) showed high enhancement mainly due to the ternary surface complexes of TPD-FA-Eu(3+) and TPD-FA-Am(3+). The SCM showed that one ion exchange (≡S3Am/Eu) and two ISCs (≡(XO)2Am/EuNO3 and ≡(YO)2Am/EuNO3) seemed more reasonable to quantitatively describe the adsorption edges of both Eu(III) and Am(III). Our findings obviously showed that Eu(III) could be a good analogue to study actinide behaviors in practical terms. However, it should be kept in mind that there are still obvious differences between the characteristics of Eu(III) and Am(III) in some special cases, for instance, the complex ability with organic matter and adsorption affinity to a solid surface.
[Mh] Termos MeSH primário: Amerício/química
Európio/química
Modelos Químicos
Compostos de Tório/química
[Mh] Termos MeSH secundário: Adsorção
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Thorium Compounds); 444W947O8O (Europium); VW92PHU2UY (Americium)
[Em] Mês de entrada:1601
[Cu] Atualização por classe:150902
[Lr] Data última revisão:
150902
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150723
[St] Status:MEDLINE
[do] DOI:10.1039/c5em00240k


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[PMID]:24462957
[Au] Autor:Ali M; Kumar A; Pandey BN
[Ad] Endereço:Radiation Biology and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
[Ti] Título:Thorium induced cytoproliferative effect in human liver cell HepG2: role of insulin-like growth factor 1 receptor and downstream signaling.
[So] Source:Chem Biol Interact;211:29-35, 2014 Mar 25.
[Is] ISSN:1872-7786
[Cp] País de publicação:Ireland
[La] Idioma:eng
[Ab] Resumo:Thorium-232 ((232)Th), a naturally-occurring actinide has gained significant attention due to its immense potential as a nuclear fuel for advanced reactors. Understanding the biological effects of (232)Th would significantly impact its efficient utilization with adequate health protection. Humans administered with (232)Th (thorotrast patients) or experimental animal models showed that liver is one of the major sites of (232)Th accumulation. Present study reports cellular effects of (232)Th-nitrate in a human-derived liver cell (HepG2). Results showed that the low concentration of (232)Th (0.1-10 µM) induced proliferation of HepG2 cells which was inhibited by the pre-treatment of cells with neutralizing antibody against insulin-like growth factor 1 receptor (IGF-1R). Consistently, (232)Th treatment was found to increase the phosphorylated level of IGF-1R-associated molecule, IRS1 which serves to activate PI3K and MAPK signaling pathways. Pre-treatment with specific inhibitors of PI3K (LY294002) or JNK-MAPK (SP600125) significantly abrogated the cytoproliferative effect of (232)Th. Immunofluorescence analysis showed increased levels of phospho-Akt and phospho-JNK, downstream kinases of IGF-1R, in (232)Th-treated HepG2 cells suggesting the role of IGF-1R-mediated signaling in (232)Th-stimulated cell proliferation. The cell cycle analysis showed that (232)Th increased S and G2-M cell fractions concomitant to the increase of cyclin-E level. Thus, the present investigation highlights the role of IGF-1R-mediated signaling in the cytoproliferative effect of (232)Th in human liver cells at low concentration.
[Mh] Termos MeSH primário: Fígado/efeitos dos fármacos
Receptor IGF Tipo 1/metabolismo
Transdução de Sinais/efeitos dos fármacos
Compostos de Tório/toxicidade
[Mh] Termos MeSH secundário: Western Blotting
Proliferação Celular/efeitos dos fármacos
Inibidores Enzimáticos/farmacologia
Ensaio de Imunoadsorção Enzimática
Células Hep G2
Seres Humanos
Fígado/patologia
Receptor IGF Tipo 1/antagonistas & inibidores
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Enzyme Inhibitors); 0 (Thorium Compounds); EC 2.7.10.1 (Receptor, IGF Type 1); IF944P467K (thorium nitrate)
[Em] Mês de entrada:1405
[Cu] Atualização por classe:161125
[Lr] Data última revisão:
161125
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140128
[St] Status:MEDLINE


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[PMID]:23930795
[Au] Autor:Oliveira MS; Duarte IM; Paiva AV; Yunes SN; Almeida CE; Mattos RC; Sarcinelli PN
[Ad] Endereço:Radioprotection and Dosimetry Institute, CNEN, Rio de Janeiro, Brazil. monica@ird.gov.br
[Ti] Título:The role of chemical interactions between thorium, cerium, and lanthanum in lymphocyte toxicity.
[So] Source:Arch Environ Occup Health;69(1):40-5, 2014.
[Is] ISSN:1933-8244
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Thorium, cerium, and lanthanum are metals present in several types of minerals, the most common of which is monazite. Cerium and lanthanum are elements in the lanthanides series. Thorium, an actinide metal, is a hazardous element due to its radioactive characteristics. There is a lack of information describing the possible chemical interactions among these elements and the effects they may have on humans. Toxicological analyses were performed using cell viability, cell death, and DNA damage assays. Chemical interactions were evaluated based on the Loewe additivity model. The results indicate that thorium and cerium individually have no toxic effects on lymphocytes. However, thorium associated with lanthanum increases the toxicity of this element, thereby reducing the viability of lymphocytes at low concentrations of metals in the mixture.
[Mh] Termos MeSH primário: Cério/toxicidade
Lantânio/toxicidade
Linfócitos/efeitos dos fármacos
Tório/toxicidade
[Mh] Termos MeSH secundário: Apoptose/efeitos dos fármacos
Sobrevivência Celular/efeitos dos fármacos
Dano ao DNA/efeitos dos fármacos
Relação Dose-Resposta a Droga
Sinergismo Farmacológico
Seres Humanos
Células Jurkat/efeitos dos fármacos
Compostos de Tório/toxicidade
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Thorium Compounds); 30K4522N6T (Cerium); 33A856C3T7 (lanthanide nitrate); 60YU5MIG9W (Thorium); 6I3K30563S (Lanthanum); IF944P467K (thorium nitrate)
[Em] Mês de entrada:1311
[Cu] Atualização por classe:161125
[Lr] Data última revisão:
161125
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:130813
[St] Status:MEDLINE
[do] DOI:10.1080/19338244.2012.719557


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[PMID]:23285669
[Au] Autor:Patil SS; Thakur GA; Shaikh MM
[Ad] Endereço:Department of Chemistry, Changu Kana Thakur Arts, Commerce and Science College, Maharashtra, India. sunilpatil_247@rediffmail.com
[Ti] Título:Synthesis, spectral, thermal and antibacterial investigations of mixed ligand complexes of thorium(IV) derived from 8-hydroxyquinoline and some amino acids.
[So] Source:Acta Pol Pharm;69(6):1087-93, 2012 Nov-Dec.
[Is] ISSN:0001-6837
[Cp] País de publicação:Poland
[La] Idioma:eng
[Ab] Resumo:Mixed ligand Th(IV) complexes of the type [M(Q)(L)(NO3)2] x 2 H2O have been synthesized using 8-hydroxyquinoline (HQ) as a primary ligand and N- and/or O- donor amino acids (HL) such as L-lysine, L-aspartic acid and L-cysteine as secondary ligands. The metal complexes have been characterized on the basis of elemental analysis, electrical conductance, room temperature magnetic susceptibility measurements,spectral and thermal studies. The electrical conductance studies of the complexes in DMF in 10(-3) M concentration indicate their non-electrolytic nature. Room temperature magnetic susceptibility measurements revealed diamagnetic nature of the complexes. Electronic absorption spectra of the complexes show intra-ligand and charge transfer transitions, respectively. Bonding of the metal ion through N- and O- donor atoms of the ligands revealed by IR studies and the chemical environment of the protons is also confirmed by NMR studies. The thermal analysis data of the complexes indicate the presence of crystallized water molecules. The agar cup and tube dilution method have been used to study the antibacterial activity of the complexes against the pathogenic bacteria S. aureus, C. diphtheriae, S. typhi and E. coli.
[Mh] Termos MeSH primário: Aminoácidos/química
Antibacterianos/síntese química
Oxiquinolina/química
Compostos de Tório/química
[Mh] Termos MeSH secundário: Antibacterianos/química
Antibacterianos/farmacologia
Ligantes
Espectroscopia de Ressonância Magnética
Espectroscopia de Infravermelho com Transformada de Fourier
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Amino Acids); 0 (Anti-Bacterial Agents); 0 (Ligands); 0 (Thorium Compounds); 5UTX5635HP (Oxyquinoline)
[Em] Mês de entrada:1306
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:130105
[St] Status:MEDLINE


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[PMID]:23124666
[Au] Autor:Reinoso-Maset E; Worsfold PJ; Keith-Roach MJ
[Ad] Endereço:Biogeochemistry and Environmental Analytical Chemistry Group, Biogeochemistry Research Centre, University of Plymouth, Plymouth, PL4 8AA, UK. estela.reinoso-maset@cea.fr
[Ti] Título:Evaluation of electrospray ionisation mass spectrometry as a technique for the investigation of competitive interactions: a case study of the ternary Th-Mn-EDTA system.
[So] Source:Rapid Commun Mass Spectrom;26(23):2755-62, 2012 Dec 15.
[Is] ISSN:1097-0231
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:RATIONALE: Electrospray ionisation mass spectrometry (ESI-MS) is a useful tool for exploring the speciation of solution-phase metal complexes; however, the quantification of ternary systems is challenging due to the differences in the electrospray response of different species. Here, the Th-Mn-EDTA system was investigated to evaluate the capability of ESI-MS for quantifying the species present. METHODS: Increasingly complex mixtures of Th(IV), Mn(II) and EDTA were analysed using manual flow injection of samples into an HPLC grade water mobile phase delivered to an ion trap mass spectrometer fitted with an ESI interface (ThermoQuest Finnigan Mat LCQ). Mass spectra were obtained in the positive and negative ion modes over a mass-to-charge (m/z) range from 50-2000. RESULTS: The instrumental response to EDTA was affected by the addition of Th(NO(3))(4) but not MnCl(2), while the response to both Th-EDTA and Mn-EDTA species was affected by addition of the other metal salt. Internal standards were also found to suppress signals to different extents. Therefore, each signal suppression was carefully quantified as the solution became more complex, and signal correction factors were used in conjunction with regular external calibration. Mixed metal signals were quantified adequately. CONCLUSIONS: This study showed the complexity of quantifying a ternary system involving different co-existing species. Nonetheless, the step-wise protocol developed provided quantitative data on the displacement of Mn from its EDTA complex by Th.
[Mh] Termos MeSH primário: Ácido Edético/química
Manganês/química
Espectrometria de Massas por Ionização por Electrospray/métodos
Tório/química
[Mh] Termos MeSH secundário: Cromatografia Líquida de Alta Pressão
Complexos de Coordenação/química
Cloreto de Magnésio/química
Compostos de Tório/química
[Pt] Tipo de publicação:EVALUATION STUDIES; JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Coordination Complexes); 0 (Thorium Compounds); 02F3473H9O (Magnesium Chloride); 42Z2K6ZL8P (Manganese); 60YU5MIG9W (Thorium); 9G34HU7RV0 (Edetic Acid); IF944P467K (thorium nitrate)
[Em] Mês de entrada:1304
[Cu] Atualização por classe:161125
[Lr] Data última revisão:
161125
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:121106
[St] Status:MEDLINE
[do] DOI:10.1002/rcm.6404


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[PMID]:22125953
[Au] Autor:Patil SS; Thakur GA; Shaikh MM
[Ad] Endereço:Department of Chemistry, Changu Kana Thakur Arts, Commerce and Science College, New Panvel, Raigad, Maharashtra 410206, India. sunilpatil_247@rediffmail.com
[Ti] Título:Synthesis, characterization and antibacterial studies on some mixed ligand thorium complexes with N- and O-donor ligands.
[So] Source:Acta Pol Pharm;68(6):881-7, 2011 Nov-Dec.
[Is] ISSN:0001-6837
[Cp] País de publicação:Poland
[La] Idioma:eng
[Ab] Resumo:Mixed ligand Th(IV) complexes of the type [M(Q)(L)(NO3)2] x 2H2O have been synthesized using 8-hydroxyquinoline (HQ) as a primary ligand and N- and/or O- donor amino acids (HL) such as L-threonine, L-tryptophan and L-isoleucine as secondary ligands. The metal complexes have been characterized on the basis of elemental analysis, electrical conductance, room temperature magnetic susceptibility measurements, spectral and thermal studies. The electrical conductance studies of the complexes in DMF in 10(-3). M concentration indicate their non-electrolytic nature. Room temperature magnetic susceptibility measurements revealed diamagnetic nature of the complexes. Electronic absorption spectra of the complexes show intra-ligand and charge transfer transitions, respectively. Bonding of the metal ion through N- and O-donor atoms of the ligands revealed by IR studies and the chemical environment of the protons is also confirmed by NMR studies. The thermal analysis data of the complexes indicate the presence of crystalline water molecules. The tube dilution method has been used to study the antibacterial activity of the complexes against the pathogenic bacteria S. aureus, C. diphtheriae, S. typhi and E. coli.
[Mh] Termos MeSH primário: Antibacterianos/síntese química
Antibacterianos/farmacologia
Nitrogênio/química
Oxigênio/química
Compostos de Tório/síntese química
Compostos de Tório/farmacologia
[Mh] Termos MeSH secundário: Aminoácidos/química
Corynebacterium diphtheriae/efeitos dos fármacos
Corynebacterium diphtheriae/crescimento & desenvolvimento
Desenho de Drogas
Condutividade Elétrica
Escherichia coli/efeitos dos fármacos
Escherichia coli/crescimento & desenvolvimento
Ligantes
Espectroscopia de Ressonância Magnética
Testes de Sensibilidade Microbiana
Estrutura Molecular
Oxiquinolina/química
Salmonella typhi/efeitos dos fármacos
Salmonella typhi/crescimento & desenvolvimento
Espectrofotometria Ultravioleta
Espectroscopia de Infravermelho com Transformada de Fourier
Staphylococcus aureus/efeitos dos fármacos
Staphylococcus aureus/crescimento & desenvolvimento
Relação Estrutura-Atividade
Tecnologia Farmacêutica/métodos
Termogravimetria
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Amino Acids); 0 (Anti-Bacterial Agents); 0 (Ligands); 0 (Thorium Compounds); 5UTX5635HP (Oxyquinoline); N762921K75 (Nitrogen); S88TT14065 (Oxygen)
[Em] Mês de entrada:1112
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:111201
[St] Status:MEDLINE


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[PMID]:21687883
[Au] Autor:Pereira CC; Marsden CJ; Marçalo J; Gibson JK
[Ad] Endereço:Unidade de Ciências Químicas e Radiofarmacêuticas, Instituto Tecnológico e Nuclear, 2686-953 Sacavém, Portugal.
[Ti] Título:Actinide sulfides in the gas phase: experimental and theoretical studies of the thermochemistry of AnS (An = Ac, Th, Pa, U, Np, Pu, Am and Cm).
[So] Source:Phys Chem Chem Phys;13(28):12940-58, 2011 Jul 28.
[Is] ISSN:1463-9084
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The gas-phase thermochemistry of actinide monosulfides, AnS, was investigated experimentally and theoretically. Fourier transform ion cyclotron resonance mass spectrometry was employed to study the reactivity of An(+) and AnO(+) (An = Th, Pa, U, Np, Pu, Am and Cm) with CS(2) and COS, as well as the reactivity of the produced AnS(+) with oxidants (COS, CO(2), CH(2)O and NO). From these experiments, An(+)-S bond dissociation energies could be bracketed. Density functional theory studies of the energetics of neutral and monocationic AnS (An = Ac, Th, Pa, U, Np, Pu, Am and Cm) provided values for bond dissociation energies and ionization energies; the computed energetics of neutral and monocationic AnO were also obtained for comparison. The theoretical data, together with comparisons with known An(+)-O bond dissociation energies and M(+)-S and M(+)-O dissociation energies for the early transition metals, allowed for the refining of the An(+)-S bond dissociation energy ranges obtained from experiment. Examination of the reactivity of AnS(+) with dienes, coupled to comparisons with reactivities of the AnO(+) analogues, systematic considerations and the theoretical results, allowed for the estimation of the ionization energies of the AnS; the bond dissociation energies of neutral AnS were consequently derived. Estimates for the case of AcS were also made, based on correlations of the data for the other An and the electronic energetics of neutral and ionic An. The nature of the bonding in the elementary molecular actinide chalcogenides (oxides and sulfides) is discussed, based on both the experimental data and the computed electronic structures. DFT calculations of ionization energies for the actinide atoms and the diatomic sulfides and oxides are relatively reliable, but the calculation of bond dissociation energies is not uniformly satisfactory, either with DFT or CCSD(T). A key conclusion from both the experimental and theoretical results is that the 5f electrons do not substantially participate in actinide-sulfur bonding. We emphasize that actinides form strikingly strong bonds with both oxygen and sulfur.
[Mh] Termos MeSH primário: Elementos da Série Actinoide/química
Gases/química
Sulfetos/química
Termodinâmica
[Mh] Termos MeSH secundário: Actínio/química
Algoritmos
Alcadienos/química
Amerício/química
Dióxido de Carbono/química
Dissulfeto de Carbono/química
Cátions Monovalentes/química
Cúrio/química
Análise de Fourier
Espectrometria de Massas/métodos
Netúnio/química
Oxidantes/química
Óxidos/química
Plutônio/química
Protoactínio/química
Óxidos de Enxofre/química
Compostos de Tório/química
Compostos de Urânio/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Nm] Nome de substância:
0 (Actinoid Series Elements); 0 (Alkadienes); 0 (Cations, Monovalent); 0 (Gases); 0 (Oxidants); 0 (Oxides); 0 (Sulfides); 0 (Sulfur Oxides); 0 (Thorium Compounds); 0 (Uranium Compounds); 0S6855V29M (Protactinium); 142M471B3J (Carbon Dioxide); 53023GN24M (Plutonium); 6200K977BQ (Neptunium); 871UI0ET21 (carbonyl sulfide); M5LL84MZ2W (Curium); NIK1K0956U (Actinium); S54S8B99E8 (Carbon Disulfide); VW92PHU2UY (Americium)
[Em] Mês de entrada:1202
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:110621
[St] Status:MEDLINE
[do] DOI:10.1039/c1cp20996e


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[PMID]:21665526
[Au] Autor:Yang WQ; Zheng WC
[Ad] Endereço:Department of Material Science, Sichuan University, Chengdu 610064, People's Republic of China.
[Ti] Título:Studies of the spin-Hamiltonian parameters and defect structures for Gd3+ ions in zircon-structure silicates MSiO4 (M=Zr, Hf, Th).
[So] Source:Spectrochim Acta A Mol Biomol Spectrosc;79(5):1291-4, 2011 Sep.
[Is] ISSN:1873-3557
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The spin-Hamiltonian parameters (g factors g∥, g⊥ and zero-field splittings b2(0), b4(0), b4(4), b6(0), b6(4)) for 4f7 ion Gd3+ at the tetragonal M4+ site of zircon-structure silicates MSiO4 (M=Zr, Hf, Th) are calculated from a diagonalization (of energy matrix) method. The Hamiltonian concerning this energy matrix contains the free-ion, crystal-field interaction and Zeeman interaction terms and the 56×56 energy matrix is constructed by considering the ground multiplet 8S7/2 and the excited multiplets 6L7/2 (L=P, D, F, G, H, I). The defect structures of Gd3+ centers in the three MSiO4 crystals are yielded from the calculation. The results are discussed.
[Mh] Termos MeSH primário: Espectroscopia de Ressonância de Spin Eletrônica
Gadolínio/química
Háfnio/química
Modelos Químicos
Silicatos/química
Compostos de Tório/química
Zircônio/química
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Silicates); 0 (Thorium Compounds); 4SY8H89134 (zircon); AU0V1LM3JT (Gadolinium); C6V6S92N3C (Zirconium); X71938L1DO (Hafnium)
[Em] Mês de entrada:1112
[Cu] Atualização por classe:131121
[Lr] Data última revisão:
131121
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:110614
[St] Status:MEDLINE
[do] DOI:10.1016/j.saa.2011.04.057


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[PMID]:21524936
[Au] Autor:Rajeswari B; Kadam RM; Dhawale BA; Babu Y; Natarajan V; Godbole SV
[Ad] Endereço:Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
[Ti] Título:EPR evidence for the restricted mobility of NO2 in gamma irradiated thorium nitrate pentahydrate Th(NO3)4·5H2O.
[So] Source:Spectrochim Acta A Mol Biomol Spectrosc;79(3):405-11, 2011 Aug.
[Is] ISSN:1873-3557
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Electron paramagnetic resonance (EPR) studies were conducted on gamma irradiated polycrystalline sample of thorium nitrate pentahydrate, Th(NO(3))(4)·5H(2)O, in the temperature range of 100-300 K. The most prominent species with triplet hyperfine structure in the EPR spectrum was identified as NO(2). The EPR spectrum gave evidence for the stabilization of NO(2) in at least three different sites slightly differing in spin Hamiltonian parameters (Site(1): g(x)=2.0042, g(y)=1.9911, g(z)=2.0020, A(x)=54.20 G, A(y)=48.50 G and A(z)=65.25 G; Site(2): g(x)=2.0042, g(y)=1.9911, g(z)=2.0020, A(x)=54.20 G, A(y)=48.50 G and A(z)=67.85 G; Site(3): g(x)=2.0045, g(y)=1.9911, g(z)=2.0015, A(x)=54.20 G, A(y)=49.05 G and A(z)=72.45 G). The EPR spectra for Site(1) revealed molecular dynamics of NO(2) from a slow motion region to fast motion region as the sample temperature was varied from 100 to 300 K. This led to a change in EPR spectrum from orthorhombic to axial, indicating preferred rotation of NO(2) molecule about the O-O bond direction. However, the NO(2) molecule at Site(2) was found to be rigid throughout the entire temperature range. The differences in the mobility of NO(2) molecules occupying the two sites could be attributed to the fact that in one case NO(2) was bonded to thorium or water and in the other case it was weakly bound. The NO(2) bound to thorium through two oxygen atoms or bound to thorium on one side through one oxygen atom and hydrogen bonded to water on the other side remains rigid throughout the entire temperature range, while NO(2) situated at interstitial sites or adsorbed on the surface exhibits mobility with increase in temperature above 100K.
[Mh] Termos MeSH primário: Dióxido de Nitrogênio/química
Compostos de Tório/química
[Mh] Termos MeSH secundário: Cristalização
Espectroscopia de Ressonância de Spin Eletrônica
Raios gama
Ligações de Hidrogênio
Simulação de Dinâmica Molecular
Temperatura Ambiente
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Thorium Compounds); IF944P467K (thorium nitrate); S7G510RUBH (Nitrogen Dioxide)
[Em] Mês de entrada:1110
[Cu] Atualização por classe:161125
[Lr] Data última revisão:
161125
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:110429
[St] Status:MEDLINE
[do] DOI:10.1016/j.saa.2011.02.031



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