RESUMO
Inosine 5'-monophosphate in acidic form and its lithium, potassium, magnesium, calcium, strontium and barium were prepared from the sodium salt, characterized by elemental analysis and Fourier transform infrared spectroscopy and submitted to thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC) and thermogravimetry coupled to infrared spectroscopy (TG-FTIR) of the volatile products evolved during heating. All the salts were hydrated containing from 4 to 7.5 H2O. After dehydration these salts decomposed releasing the nitrogenous base followed by the ribose group, and producing pyrophosphates as final residue. Evolved Gas Analysis (EGA) reveled the release of water, isocyanic acid and hydrocyanic acid during decomposition of the organic moiety. It was observed only water loss up to 200⯰C. At temperatures above 200⯰C, the nucleotides were unstable and decomposed, implying that foods containing those additives should be processed below this temperature. Finally, a general mechanism for the decomposition of the inosinates was proposed.
Assuntos
Inosina Monofosfato/química , Bário/química , Varredura Diferencial de Calorimetria , Lítio/química , Magnésio/química , Potássio/química , Sais/química , Espectroscopia de Infravermelho com Transformada de Fourier , Estrôncio/química , Temperatura , Termogravimetria , Água/químicaRESUMO
Formation water (FoW) is a by-product from oil and gas production and usually has high concentrations of soluble salts and metals. Calcium (Ca) and magnesium (Mg) have been shown to reduce the toxicity of metals to aquatic animals, and previous study showed that high waterborne Ca exerts mild effect against disturbances on Na+ regulation in Amazonian armored catfish tamoatá (Hoplosternum littorale) acutely exposed to high Fe, Mn, and Ba levels. Here, we hypothesized that high Mg levels might also reduce the toxic effects of these metals on Na+ regulation of tamoatá. The exposure to 5% FoW promoted an increase in Na+ uptake and a rapid accumulation of Na+ in all tissues analyzed (kidneyAssuntos
Bário/química
, Cálcio/metabolismo
, Peixes-Gato/metabolismo
, Brânquias/metabolismo
, Íons/química
, Magnésio/química
, Sódio/metabolismo
, Poluentes Químicos da Água/análise
, Animais
, Bário/toxicidade
, Cálcio/toxicidade
, Magnésio/toxicidade
, Sódio/química
, Sódio/toxicidade
, Poluentes Químicos da Água/química
RESUMO
The petroleum industry generates a range of wastes which is often are disposed in soil close to the well location, negatively affecting soil and water quality. The objective of this study was to evaluate the solubility and map the spatial variability of barium in a potentially contaminated area. The study area consisted of a petroleum well-drilling waste disposal site located in the municipality of Mato Rico-PR. A large georeferenced sampling grid was organized. Soil samples were collected at depths of 30, 60, 90, and 120 cm for determination of the "pseudo-total" concentrations and geochemical fractionation of barium. The barium concentrations showed spatial dependence, which permitted the use of geostatistical interpolators. Regarding depth, the depth of 0-30 cm showed the largest contaminated area; however, higher concentrations of barium were found at the depth of 60-90 cm. The results of geochemical fractionation showed that the analyzed samples contained percentages higher than 99% in the non-labile fraction (residual). These results indicate clearly that the barium was in a condition of low solubility, even for samples that had the highest concentrations, presenting low-environmental risk.
Assuntos
Bário/análise , Resíduos Industriais , Campos de Petróleo e Gás , Petróleo , Poluentes do Solo/análise , Instalações de Eliminação de Resíduos , Bário/química , Monitoramento Ambiental , Poluentes do Solo/química , Solubilidade , Análise EspacialRESUMO
PURPOSE: Nutrients and immunological factors of breast milk are essential for newborn growth and the development of their immune system, but this secretion can contain organic and inorganic toxins such as barium. Colostrum contamination with barium is an important issue to investigate because this naturally occurring element is also associated with human activity and industrial pollution. The study evaluated the administration of barium nanoparticles to colostrum, assessing the viability and functional activity of colostral mononuclear phagocytes. METHODS: Colostrum was collected from 24 clinically healthy women (aged 18-35 years). Cell viability, superoxide release, intracellular Ca(2+) release, and phagocyte apoptosis were analyzed in the samples. RESULTS: Treatment with barium lowered mononuclear phagocyte viability, increased superoxide release, and reduced intracellular calcium release. In addition, barium increased cell death by apoptosis. CONCLUSION: These data suggest that nanoparticles of barium in colostrum are toxic to cells, showing the importance of avoiding exposure to this element.
Assuntos
Apoptose/efeitos dos fármacos , Bário/química , Colostro/efeitos dos fármacos , Nanopartículas/administração & dosagem , Fagócitos/patologia , Adolescente , Adulto , Cálcio/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Feminino , Citometria de Fluxo , Humanos , Nanopartículas/química , Fagócitos/efeitos dos fármacos , Gravidez , Superóxidos/metabolismo , Adulto JovemRESUMO
Otolith microchemistry was applied to quantify migratory variation and the proportion of native Caribbean stream fishes that undergo full or partial marine migration. Strontium and barium water chemistry in four Puerto Rico, U.S.A., rivers was clearly related to a salinity gradient; however, variation in water barium, and thus fish otoliths, was also dependent on river basin. Strontium was the most accurate index of longitudinal migration in tropical diadromous fish otoliths. Among the four species examined, bigmouth sleeper Gobiomorus dormitor, mountain mullet Agonostomus monticola, sirajo goby Sicydium spp. and river goby Awaous banana, most individuals were fully amphidromous, but 9-12% were semi-amphidromous as recruits, having never experienced marine or estuarine conditions in early life stages and showing no evidence of marine elemental signatures in their otolith core. Populations of one species, G. dormitor, may have contained a small contingent of semi-amphidromous adults, migratory individuals that periodically occupied marine or estuarine habitats (4%); however, adult migratory elemental signatures may have been confounded with those related to diet and physiology. These findings indicate the plasticity of migratory strategies of tropical diadromous fishes, which may be more variable than simple categorization might suggest.
Assuntos
Migração Animal , Peixes/fisiologia , Membrana dos Otólitos/química , Animais , Bário/química , Porto Rico , Estrôncio/química , Água/químicaRESUMO
An in vivo intercomparison exercise, organised in the scope of the IAEA Regional Latin American (RLA) Project 9066, was carried out in 2009 aimed to harmonise measurement procedures on the measurement of (131)I in the thyroid among Latin American and Caribbean countries. The exercise consisted in the measurement of an anthropomorphic thyroid phantom spiked with a certified source of (133)Ba. The phantom was supplied by the In Vivo Monitoring Laboratory of Institute for Radiation Protection and Dosimetry (IRD) to 17 Institutions from 12 countries of the regions. Among these, 13 Institutions from 10 countries returned their measurement results as well as a standard report form containing detailed information about their respective counting facilities. All participants reported activities within an acceptable range, considering American National Standard Institute (ANSI) limits. Uncertainties varied from 0.04 to 12.9 %. Although results show that the general performance was acceptable in terms of accuracy, the need for additional action towards the standardisation of uncertainty estimation in this type of measurement in the region should be highlighted.
Assuntos
Radioisótopos do Iodo/análise , Monitoramento de Radiação/métodos , Proteção Radiológica/métodos , Radiometria/métodos , Bário/química , Região do Caribe , Humanos , América Latina , Imagens de Fantasmas , Cintilografia , Reprodutibilidade dos Testes , Glândula Tireoide/diagnóstico por imagemRESUMO
The adsorption of barium by Ca-exchanged clinoptilolite and montmorillonite is presented. The kinetics of adsorption of Ba(2+) were evaluated contacting 1g portion of each adsorber with 100mL 0.1N BaCl(2) for 200 h. Adsorption by Ca-clinoptilolite is defined by second-order kinetics of rate constant K(v) 8.232 x 10(-2) g mg(-1)h(-1) and maximum removal of 71.885 mg g(-1). It is a two-stage process initiated by a rapid uptake of Ba(2+) followed by more moderate kinetics. The adsorption isotherms were determined contacting 0.2g of each adsorber with 10 mL 0.1-0.005N BaCl(2)+CaCl(2) solution, Ba(2+)/Ca(2+) ratio 1, for periods of 7 days for the tuff and 2 days for the clay. The equilibrium adsorption is described by the Langmuir model, of equilibrium constant K 0.0151 L mg(-1) and maximum adsorption of 15.29 mg g(-1). The adsorption of Ba(2+) by Ca-exchanged montmorillonite also follows a second-order reaction of rate constant K(v) 3.179 x 10(-2) g mg(-1)h(-1), and calculated separation of 36.74 mg g(-1); the Langmuir isotherm is defined by the constant K 0.034 L mg(-1) and maximum adsorption of 15.29 mg g(-1). X-ray diffraction shows that the exchange of Ba(2+) modifies the d(001) of Ca-montmorillonite from 15.4 to 12.4A.
Assuntos
Bário/química , Bentonita/química , Cálcio/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Zeolitas/química , Adsorção , Silicatos de Alumínio , Argila , Temperatura Alta , Cinética , Temperatura , Fatores de Tempo , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análiseRESUMO
The quantitative determination of chemical elements in organic or biological samples is an important analytical problem. Normally the elements to be determined in the organic matrix must be transformed into a simple inorganic form. A digestion method by heating on a block digestor has been developed for the determination of Al, As, Ba, Ca, Cd, Co, Cu, Fe, Mg, Mn, V and Zn in Oyster tissue by ICP OES. A simplex centroid statistical mixture design has been used to study the effects of changing HNO(3), HCl and H(2)O(2) reagent proportions on the digestion of these samples. Response surface and principal component analyses show that the species Ca, Cd, Cu, Fe, Mg, Mn and Zn have very similar analytical tendencies under this experiment. By means of mixture modeling maximum recoveries for these ions were predicted using 19%, 18% and 63% of the HCl, HNO(3) and H(2)O(2) pseudocomponent mixtures, respectively. This corresponds to 21.4%, 30.8% and 47.8% of the HCl, HNO(3) and H(2)O(2) commercial solutions. Furthermore the As, Co and V ions present large recoveries for these mixtures as well. The Al and Ba ion recoveries are seen to be independent of the mixture proportions. The analysis of Oyster tissue reference material (SRM 1566b - NIST) under optimized conditions at the selected wavelengths resulted in ion recoveries between 90% and 100%.
Assuntos
Técnicas de Química Analítica/métodos , Metais/análise , Ostreidae/química , Análise Espectral/métodos , Alumínio/análise , Alumínio/química , Análise de Variância , Animais , Arsênio/análise , Arsênio/química , Bário/análise , Bário/química , Cádmio/análise , Cádmio/química , Cálcio/análise , Cálcio/química , Cobalto/análise , Cobalto/química , Cobre/análise , Cobre/química , Ácido Clorídrico/química , Peróxido de Hidrogênio/química , Íons/análise , Íons/química , Ferro/análise , Ferro/química , Magnésio/análise , Magnésio/química , Manganês/análise , Manganês/química , Metais/química , Ácido Nítrico/química , Reprodutibilidade dos Testes , Vanádio/análise , Vanádio/química , Zinco/análise , Zinco/químicaRESUMO
Ba(Mn1/3Nb2/3)O3 ceramics were synthesized by the microwave-hydrothermal process. Crystalline, single-phase, needle-like materials were obtained with high anisotropy and aspect ratio. Large crystals could be prepared from a direct combination of nanosized crystals under microwaves through an oriented attachment mechanism. Infrared and Raman spectroscopies showed perfect agreement with group-theoretical approaches for a trigonal, P3m1 structure. Franck-Condon modes were identified in Raman scattering experiments conducted in different wavelengths, laser powers, and temperatures. The results showed that the Mn ions exhibit a particular role in the lattice dynamics in complex perovskites.
Assuntos
Bário/química , Elétrons , Manganês/química , Nióbio/química , Óxidos/síntese química , Temperatura , Micro-Ondas , Óxidos/química , Análise Espectral Raman/métodos , VibraçãoRESUMO
The perovskite Gd(0.9)Ba(0.1)CoO3 was prepared via solution and solution-polymerization methods in aqueous media. The thermal decomposition of precursor powders produced well crystallized nanostructured materials possessing an extensive nanoporosity. The average particle size obtained by the solution route was 150 nm, whereas by the solution-polymerization method was 61 nm. The characterization of gas response, performed on thick-films, revealed that the electrical resistance variation increases with reducing grain size. In oxygen, the films prepared with powder of solution-polymerization registered an increment of 1000%, compared to the powder made by the solution route, whereas in carbon dioxide was 1100%.