15 resultados para Trace semantics
em Scielo Saúde Pública - SP
Resumo:
OBJECTIVE:To evaluate public health dentistry practices of two different family health models. METHODS: Qualitative study conducted with data obtained from focus groups consisting of 58 dentists working in the Family Health Strategy for at least three years between August-October, 2006. The Paideia Family Health Approach was used in the city of Campinas and the Oral Health Initiative as part of the Family Health Strategy was implemented in the city of Curitiba, Southeastern and Southern Brazil, respectively. Data was analyzed using the hermeneutic-dialectic method. Analysis indicators were employed to indicate backwardness, stagnation or progress in oral health practices effective from the implementation of the strategies referred. The indicators used were: work process; interdisciplinary approach; territorialization; capacity building of human resources; health promotion practices; and responsiveness to users' demands. RESULTS: There was progress in user access to services, humanization of health care, patient welcoming and patient-provider relationship. The results related to health promotion practices, territorialization, interdisciplinary approach and resource capacity building indicated a need for technical and operational enhancements in both cities. CONCLUSIONS: Both models have brought about important advances in terms of increased access to services and humanization of health care. Universal access to oral health at all levels of complexity was not achieved in both cities studied. Local health managers and oral health program coordinators must bring more weight to bear in the arena that defines public policy priorities.
Resumo:
Synthetic root exudates were formulated based on the organic acid composition of root exudates derived from the rhizosphere of aseptically grown corn plants, pH of the rhizosphere, and the background chemical matrices of the soil solutions. The synthetic root exudates, which mimic the chemical conditions of the rhizosphere environment where soil-borne metals are dissolved and absorbed by plants, were used to extract metals from sewage-sludge treated soils 16 successive times. The concentrations of Zn, Cd, Ni, Cr, and Cu of the sludge-treated soil were 71.74, 0.21, 15.90, 58.12, and 37.44 mg kg-1, respectively. The composition of synthetic root exudates consisted of acetic, butyric, glutaric, lactic, maleic, propionic, pyruvic, succinic, tartaric, and valeric acids. The organic acid mixtures had concentrations of 0.05 and 0.1 mol L-1 -COOH. The trace elements removed by successive extractions may be considered representative for the availability of these metals to plants in these soils. The chemical speciation of the metals in the liquid phase was calculated; results showed that metals in sludge-treated soils were dissolved and formed soluble complexes with the different organic acid-based root exudates. The most reactive organic acid ligands were lactate, maleate, tartarate, and acetate. The inorganic ligands of chloride and sulfate played insignificant roles in metal dissolution. Except for Cd, free ions did not represent an important chemical species of the metals in the soil rhizosphere. As different metals formed soluble complexes with different ligands in the rhizosphere, no extractor, based on a single reagent would be able to recover all of the potentially plant-available metals from soils; the root exudate-derived organic acid mixtures tested in this study may be better suited to recover potentially plant-available metals from soils than the conventional extractors.
Resumo:
The aim of this work was to quantify low molecular weight organic acids in the rhizosphere of plants grown in a sewage sludge-treated media, and to assess the correlation between the release of the acids and the concentrations of trace-elements in the shoots of the plants. The species utilized in the experiment were cultivated in sand and sewage sludge-treated sand. The acetic, citric, lactic, and oxalic acids, were identified and quantified by high performance liquid chromatography in samples collected from a hydroponics system. Averages obtained from each treatment, concentration of trace elements in shoots and concentration of organic acids in the rhizosphere, were compared by Tukey test, at 5% of probability. Linear correlation analysis was applied to verify an association between the concentrations of organic acids and of trace elements. The average composition of organic acids for all plants was: 43.2, 31.1, 20.4 and 5.3% for acetic, citric, lactic, and oxalic acids, respectively. All organic acids evaluated, except for the citric acid, showed a close statistical agreement with the concentrations of Cd, Cu, Ni, and Zn found in the shoots. There is a positive relationship between organic acids present in the rhizosphere and trace element phytoavailability.
Resumo:
Ultra-trace amounts of Cu(II) were separated and preconcentrated by solid phase extraction on octadecyl-bonded silica membrane disks modified with a new Schiff,s base (Bis- (2-Hydroxyacetophenone) -2,2-dimethyl-1,3-propanediimine) (SBTD) followed by elution and inductively coupled plasma atomic emission spectrometric detection. The method was applied as a separation and detection method for copper(II) in environmental and biological samples. Extraction efficiency and the influence of sample matrix, flow rate, pH, and type and minimum amount of stripping acid were investigated. The concentration factor and detection limit of the proposed method are 500 and 12.5 pg mL-1, respectively.
Resumo:
An efficient flotation method based on the combination of flame atomic absorption spectrometry (FAAS) and separation and preconcentration step for determination of Cr3+, Cu 2+, Co2+, Ni2+, Zn2+, Cd 2+, Fe3+ and Pb2+ ions in various real samples by the possibility of applying bis(2-hydroxyacetophenone)-1,4-butanediimine (BHABDI) as a new collector was studied. The influence of pH, amount of BHABDI as collector, sample matrix, type and amount of eluting agent, type and amount of surfactant as floating agent, ionic strength and air flow rates i.e. variables affecting the efficiency of the extraction system was evaluated. It is ascertained that metal ions such as iron can be separated simultaneously from matrix in the presence of 0.012 mM ligand, 0.025% (w/v) of CTAB to a test sample of 750 mL at pH 6.5. These ions can be eluted quantitatively with 6 mL of 1.0 mol L-1 HNO3 in methanol which lead to the enrichment factor of 125. The detection limits for analyte ions were in the range of 1.3-2.4 ng mL-1. The method has been successfully applied for determination of trace amounts of ions in various real samples.
Resumo:
The application of organo nanoclay 5-(4-dimethylamino-benzylidene) rhodanine-immobilized as a new, easily prepared, and stable solid sorbent for preconcentration trace amounts of Au(III) ions in aqueous solution is presented. The sorption of Au(III) ions was quantitative in the pH range of 2-4, and quantitative desorption occurred instantaneously with 10.0 mL of a mixture containing 0.5 mol L-1 Na2S2O3 and KSCN. Various parameters, such as the effect of pH, breakthrough volume, extraction time, and interference of a large number of anions and cations have been studied. The proposed method has been applied for determination of trace amount of gold in water samples.
Resumo:
A simple ion pair-dispersive liquid-liquid microextraction method was proposed for preconcentration trace amounts of rhodium. An ion association complex of RhCl4- and tetradecyldimetylbenzylamonium was extracted into cholorobenzene. The volume and the type of extractive and dispersive solvents, the extraction time and the pH of the aqueous solutions were optimized. The calibration curve was linear in the range of 0.6-500 ng mL-1 of rhodium. The limit of detection was 0.10 ng mL-1 in initial solution and preconcentration factor was 40. The proposed method was successfully applied to the extraction and determination of rhodium in road dust and water samples.
Resumo:
In the proposed method, carbon tetrachloride and ethanol were used as extraction and dispersive solvents. Several factors that may be affected on the extraction process, such as extraction solvent, disperser solvent, the volume of extraction and disperser solvent, pH of the aqueous solution and extraction time were optimized. Under the optimal conditions, linearity was maintained between 1.0 ng mL-1 to 1.5 mg mL-1 for zinc and 1.0 ng mL-1 to 0.4 mg mL-1 for cadmium. The proposed method has been applied for determination of trace amount of zinc and cadmium in standard and water samples with satisfactory results.
Resumo:
A new cloud point extraction (CPE) method was developed for the separation and preconcentration of copper (II) prior to spectrophotometric analysis. For this purpose, 1-(2,4-dimethylphenyl) azonapthalen-2-ol (Sudan II) was used as a chelating agent and the solution pH was adjusted to 10.0 with borate buffer. Polyethylene glycol tert-octylphenyl ether (Triton X-114) was used as an extracting agent in the presence of sodium dodecylsulphate (SDS). After phase separation, based on the cloud point of the mixture, the surfactant-rich phase was diluted with acetone, and the enriched analyte was spectrophotometrically determined at 537 nm. The variables affecting CPE efficiency were optimized. The calibration curve was linear within the range 0.285-20 µg L-1 with a detection limit of 0.085 µg L-1. The method was successfully applied to the quantification of copper in different beverage samples.
Resumo:
In this study, a procedure is developed for cloud point extraction of Pd(II) and Rh(III) ions in aqueous solution using Span 80 (non-ionic surfactant) prior to their determination by flame atomic absorption spectroscopy. This method is based on the extraction of Pd(II) and Rh(III) ions at a pH of 10 using Span 80 with no chelating agent. We investigated the effect of various parameters on the recovery of the analyte ions, including pH, equilibration temperature and time, concentration of Span 80, and ionic strength. Under the best experimental conditions, the limits of detection based on 3Sb for Pd(II) and Rh(III) ions were 1.3 and 1.2 ng mL-1, respectively. Seven replicate determinations of a mixture of 0.5 µg mL-1 palladium and rhodium ions gave a mean absorbance of 0.058 and 0.053 with relative standard deviations of 1.8 and 1.6%, respectively. The developed method was successfully applied to the extraction and determination of the palladium and rhodium ions in road dust and standard samples and satisfactory results were obtained.
Resumo:
A simple preconcentration method of silicon based on coprecipitation with aluminum hydroxide prior to its flame atomic absorption (FAAS) determination was established. The recovery values of analyte ion was higher than 95%. The parameters including types of hydroxide ion source for precipitation, acid type for dissolution step, amount of aluminum ion as collector, pH, temperature, standing and centrifuge time, and sample volume were optimized for the quantitative recovery of the analyte. The influences of matrix ions were also examined. The relative standard deviation was found to be 3.2%. The limit of detection was calculated as (0.1 mg L-1). The preconcentration factor is 100 for (200 mL) solution. The proposed method was successfully applied for the determination of silicon in some water and alloy samples.
Resumo:
In this study, dispersive liquid-liquid microextraction based on the solidification of floating organic droplets was used for the preconcentration and determination of thorium in the water samples. In this method, acetone and 1-undecanol were used as disperser and extraction solvents, respectively, and the ligand 1-(2-thenoyl)-3,3,3-trifluoracetone reagent (TTA) and Aliquat 336 was used as a chelating agent and an ion-paring reagent, for the extraction of thorium, respectively. Inductively coupled plasma-optical emission spectrometry was applied for the quantitation of the analyte after preconcentration. The effect of various factors, such as the extraction and disperser solvent, sample pH, concentration of TTA and concentration of aliquat336 were investigated. Under the optimum conditions, the calibration graph was linear within the thorium content range of 1.0-250 µg L-1 with a detection limit of 0.2 µg L-1. The method was also successfully applied for the determination of thorium in the different water samples.
Resumo:
In the paper Busaniche and Cignoli (2009) we presented a quasivariety of commutative residuated lattices, called NPc-lattices, that serves as an algebraic semantics for paraconsistent Nelson's logic. In the present paper we show that NPc-lattices form a subvariety of the variety of commutative residuated lattices, we study congruences of NPc-lattices and some subvarieties of NPc-lattices.
Resumo:
Contemporary logic is confined to a few paradigmatic attitudes such as belief, knowledge, desire and intention. My purpose is to present a general model-theoretical semantics of propositional attitudes of any cognitive or volitive mode. In my view, one can recursively define the set of all psychological modes of attitudes. As Descartes anticipated, the two primitive modes are those of belief and desire. Complex modes are obtained by adding to primitive modes special cognitive and volitive ways or special propositional content or preparatory conditions. According to standard logic of attitudes (Hintikka), human agents are either perfectly rational or totally irrational. I will proceed to a finer analysis of propositional attitudes that accounts for our imperfect but minimal rationality. For that purpose I will use a non standard predicative logic according to which propositions with the same truth conditions can have different cognitive values and I will explicate subjective in addition to objective possibilities. Next I will enumerate valid laws of my general logic of propositional attitudes. At the end I will state principles according to which minimally rational agents dynamically revise attitudes of any mode.
Resumo:
Abstract In Turkey and several Middle East countries' people consume “leblebi” which is a traditional snack food made from chickpeas (Cicer arietinum L.). Chickpea products are highly nutritive and a cheap food for human consumption and have become an essential part of daily diets in the world. The present study aims to determine the chemical, nutritional and dietary composition of fifty leblebi samples marketed in Turkey. Protein values of the leblebi ranged from 19.4 to 23.9% dehulled and 20.3 to 20.8% for nondehulled leblebi while a value of 19.1% was recorded for chickpeas. Mineral results showed that Potassium (K) was the most abundant element in leblebi ranging from 6514 to 14431 mg/kg. The amount of dietary components neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) and cellulose did not vary much between the samples analyzed.