988 resultados para Congressos da SPE


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Objetivou-se com este trabalho avaliar a ponta XR na deposição da calda de pulverização com diferentes combinações de plantas de feijão, Brachiaria plantaginea e Bidens pilosa, em dois volumes de aplicação, com e sem a adição de surfatante Silwet. Foi utilizado como traçador o corante Azul Brilhante FDC -1 na concentração de 500 ppm para quantificar a deposição. Os tratamentos constituíram-se de sete combinações de plantas: (feijão), (B. plantaginea), (B. pilosa), (feijão + B. plantaginea), (feijão + B. pilosa), (B. plantaginea + B. pilosa) e (feijão + B. plantaginea + B. pilosa). O delineamento experimental foi o inteiramente casualizado. Foram avaliadas as pontas de jato plano XR 110015 VS e XR 11002 VS com volumes de aplicação de 150 e 200 L ha-1, respectivamente, com e sem a presença do Silwet a 0,05% v v-1. Após a aplicação, as plantas foram imediatamente coletadas e, em seguida, lavadas em 100 mL de água destilada, para posterior quantificação do traçador em espectrofotômetro. As pontas XR apresentaram comportamento distinto na deposição das gotas de pulverização nas espécies estudadas; a adição de um surfatante à calda de pulverização aumentou a uniformidade da deposição nos alvos e contribuiu para a redução do volume de aplicação.

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A method for the identification and quantification of pesticide residues in water, soil, and sediment samples has been developed, validated, and applied for the analysis of real samples. The specificity was determined by the retention time and the confirmation and quantification of analyte ions. Linearity was demonstrated over the concentration range of 20 to 120 µg L(-1), and the correlation coefficients varied between 0.979 and 0.996, depending on the analytes. The recovery rates for all analytes in the studied matrix were between 86% and 112%. The intermediate precision and repeatability were determined at three concentration levels (40, 80, and 120 µg L(-1)), with the relative standard deviation for the intermediate precision between 1% and 5.3% and the repeatability varying between 2% and 13.4% for individual analytes. The limits of detection and quantification for fipronil, fipronil sulfide, fipronil-sulfone, and fipronil-desulfinyl were 6.2, 3.0, 6.6, and 4.0 ng L(-1) and 20.4, 9.0, 21.6, and 13.0 ng L(-1), respectively. The method developed was used in water, soil, and sediment samples containing 2.1 mg L(-1) and 1.2% and 5.3% of carbon, respectively. The recovery of pesticides in the environmental matrices varied from 88.26 to 109.63% for the lowest fortification level (40 and 100 µg kg(-1)), from 91.17 to 110.18% for the intermediate level (80 and 200 µg kg(-1)), and from 89.09 to 109.82% for the highest fortification level (120 and 300 µg kg(-1)). The relative standard deviation for the recovery of pesticides was under 15%.

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In 2001, it was estimated that pesticide used worldwide exceeded 2.27 billion kilograms, over 35%, of which, were herbicides. Brazil is considered one of the leaders in the production of sugarcane and mainly ethanol as fuel. The monoculture of sugarcane requires the usage of a range of pesticides, among these, the herbicides diuron and tebuthiuron. The degradation products most studied (DCA and DCPU) are diuron's, especially for toxicological characteristics of this herbicide that is identified as carcinogen and suspected to be endocrine disruptor in mammals. After optimization of the chromatographic separation using HPLC-UV, the analytical curve was constructed in solvent and subsequently in the matrix (surface water). The extraction method contains the usage of SPE (solid phase extraction) (Strata-X, 200 mg/6 mL), applicating 1L of sample and elution with 5 mL of acetonitrile / methanol (50:50, v/v). Analysis by HPLC/UV was performed in gradient mode, acetonitrile/water (70/30-74/26 by 1 min, 74/26 - 78/22 till 3.2 min, returning to initial conditions and remaining this way until 10 min), 018 column (Phenomenex, 4.6 mm diameter, 250 mm long and 5pm particle size) and detection at 254 nm. Tests F and t were performed to verify the presence of the matrix effect. There was matrix effect to all analytes, ranging from -33% (DCA) and 38% (tebuthiuron). Thereby the method was optimized and validated for analysis of diuron, tebuthiuron, and DCPU DCA in surface water using HPLC/UV. The data obtained show that in order to assure the analytical reliability desired the use of the analytical curves in the matrix for the quantification of these analytes in water is required.

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Abstracts : The development of analytic methods more selective and sensitive is of great importance for a better quality in the determination of chemical species, therefore increasing the reliability of the results. In this way, the optimization of separation/concentration is still necessary. The use of Molecularly Imprinted Polymers - MIPs have demonstrated to be an efficient tool of analysis with a great potential in minimizing limitations of separation/concentration techniques traditionally employed. In general, the MIPs are obtained by polymerization in the presence of a template to be imprinted so that a polymeric skeleton is formed around the future analyte. In the present work, the template used is Estradiol Valerate (EV), compound used in the hormone replacement therapy (HRT) during climacteric. After the polymerization in bulk and in an anaerobic environment using MAA, EGDMA, AIBN, acetonitrile and VE, the obtained MIP was powdered, sifted (<120 μm) and placed in a soxhlet system containing ethanol at 60 °C, in order to remove the imprinted molecule through six successive washes in periods of 24 hours. The water used in the washings was analyzed using HPLC and spectrophotometry UV/Vis. Then, the obtained MIP was dried at room temperature and 150 mg was inset in SPE cartridges in order to evaluate the polymer's efficiency in the analyte pre-concentration and extraction. To do so, 100,0 mL of VE standard solution (2mg L-1) were pre-concentrated at 4,0 mL min-1 and eluted with 10,0 mL ethanol at 1,0 mL min-1, obtaining recoveries of 53%. Additionally, a NIP (non-imprinting polymer) was prepared to compare the obtained results, in which the recovery was 80%. In the same way, studies were conducted using commercial Strata™-X cartridges, obtaining 53% recovery. Since, the results did not reflect that than was expected, in relation with the MIP efficiency in the recovery, a computational ...

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Clinical decisions in dentistry are often based on the knowledge obtained during graduation, clinical experience, information shared with colleagues and professor, textbooks, seminars, conferences and continuing education courses. However, it is necessary to know if this information is derived from scientifically validated researches since too much information may complicate this process. Initially in medicine and later in other health areas a method which enables a critical evaluation of scientific papers related to a specific issue and also, whenever it is possible, an evaluation of the results by meta-analysis,was developed by Cochrane in order to reduce the bias towards all information obtained. The aim of this work is to present some aspects of the Evidence Based Dentistry (EBD) and to show how this methodology can be used to better substantiate scientifically the clinical decision of the dentist and improve researches design with scientific validity. The paper discusses editorial trends focused on the EBD, shows the differences between a systematic and a conventional review, describes data about Cochrane and the advantages of scientific evidence synthesis and the implications of EBD for clinical practice and research as well as recommendation grades and evidence levels of general scientific studies.

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Recent orthodontic bonding materials have aimed to reduce the working time of the clinician, by simplifying the acid etching procedure by applying self-etching primer adhesive systems. However, the adhesion quality of these materials still demands investigation. Thus, the present study aimed to evaluate the bond strengths of three different adhesive systems. A hundred and eighty bovine lower incisors were cut and embebbed in acrylic resin matrices, in which orthodontic brackets were bonded with Transbond XT (2n = 60), Transbond XT Self Etching Primer (2n = 60) e Tyrian (2n = 60). For each composite, bond strength tests were executed immediately (n = 30) and 24 hours (n = 30) after the bonding, in the assay machine Versat 2000 (Pantec), by applying 500 Kgf of load at 1mm/min of velocity. Transbond XT, Transbond XT Self Etching Primer and Tyrian presented, respectively, average values of bond strength of 7.43, 7.09 and 3.41 MPa at the time immediately, and 7.42, 8.81 and 5.35 MPa at 24 hours after the bonding, where differences were statistically significant at 5% between Tyrian and Transbond groups at both observation times. It was concluded that Tyrian was the material that presented significant lower bond strength with regard to Transbond groups that were similar.

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This article reviews the history of the famous painting by Leonardo da Vinci, the Mona Lisa or Gioconda, sixteenth century, aiming to discuss about some of the multiple senses (or discourses) around its meaning, with the support of the French branch of the Discourse Analysis, especially based on concepts developed by D. Maingueneau. As it is characteristic of the work of art, the senses are open, which does not exclude the possibility of detachment, among which we accentuated the "Mona Lisa smile" as one of the main traits of the authorship by Leonardo Da Vinci and, simultaneously, a trait propitious to aphorisation. Thus, the work of art is releasing of the exclusive authorship of Da Vinci and it suscitates several rereadings, which help composing a discursive ethos around this consecrated painting and, at the same time, which make circulating distinct stereotypes.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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With respect to design, scientific production in the area helps consolidate it as a scientific field can contribute to the development of society through the promotion of the construction of critical knowledge of researchers. Scientific conferences and journals, periodicals and books consist of some of the effective actions for the exchange of knowledge. Through these channels the results of research are disseminated, shared and put into discussion, collaborating with the learning process and cooperation among sectors. Thus, this paper reflects on the evolution of scientific research in the area and attempts to give an overview of current research of Design in Brazil and its correlation with the Graduate Program in Design.

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Incorporating contaminated leather waste into natural rubber improves the rubber's mechanical properties and avoids improper disposal of toxins.

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Pós-graduação em Educação - FFC

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)