917 resultados para Carfentrazone-ethyl
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An analytical methodology based on headspace solid phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography—time-of-flight mass spectrometry (GC × GC–ToFMS) was developed for the identification and quantification of the toxic contaminant ethyl carbamate (EC) directly in fortified wines. The method performance was assessed for dry/medium dry and sweet/medium sweet model wines, and for quantification purposes, calibration plots were performed for both matrices using the ion extraction chromatography (IEC) mode (m/z 62). Good linearity was obtained with a regression coefficient (r2) higher than 0.981. A good precision was attained (R.S.D. <20%) and low detection limits (LOD) were achieved for dry (4.31 μg/L) and sweet (2.75 μg/L) model wines. The quantification limits (LOQ) and recovery for dry wines were 14.38 μg/L and 88.6%, whereas for sweet wines were 9.16 μg/L and 99.4%, respectively. The higher performance was attainted with sweet model wine, as increasing of glucose content improves the volatile compound in headspace, and a better linearity, recovery and precision were achieved. The analytical methodology was applied to analyse 20 fortified Madeira wines including different types of wine (dry, medium dry, sweet, and medium sweet) obtained from several harvests in Madeira Island (Portugal). The EC levels ranged from 54.1 μg/L (medium dry) to 162.5 μg/L (medium sweet).
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A stir bar sorptive extraction with liquid desorption followed by large volume injection coupled to gas chromatography–quadrupole mass spectrometry (SBSE-LD/LVI-GC–qMS) was evaluated for the simultaneous determination of higher alcohol acetates (HAA), isoamyl esters (IsoE) and ethyl esters (EE) of fatty acids. The method performance was assessed and compared with other solventless technique, the solid-phase microextraction (SPME) in headspace mode (HS). For both techniques, influential experimental parameters were optimised to provide sensitive and robust methods. The SBSE-LD/LVI methodology was previously optimised in terms of extraction time, influence of ethanol in the matrix, liquid desorption (LD) conditions and instrumental settings. Higher extraction efficiency was obtained using 60 min of extraction time, 10% ethanol content, n-pentane as desorption solvent, 15 min for the back-extraction period, 10 mL min−1 for the solvent vent flow rate and 10 °C for the inlet temperature. For HS-SPME, the fibre coated with 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) afforded highest extraction efficiency, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 25 °C for 60 min under continuous stirring in the presence of sodium chloride (10% (w/v)). Both methodologies showed good linearity over the concentration range tested, with correlation coefficients higher than 0.984 for HS-SPME and 0.982 for SBES-LD approach, for all analytes. A good reproducibility was attained and low detection limits were achieved using both SBSE-LD (0.03–28.96 μg L−1) and HS-SPME (0.02–20.29 μg L−1) methodologies. The quantification limits for SBSE-LD approach ranging from 0.11 to 96.56 μg L−and from 0.06 to 67.63 μg L−1 for HS-SPME. Using the HS-SPME approach an average recovery of about 70% was obtained whilst by using SBSE-LD obtained average recovery were close to 80%. The analytical and procedural advantages and disadvantages of these two methods have been compared. Both analytical methods were used to determine the HAA, IsoE and EE fatty acids content in “Terras Madeirenses” table wines. A total of 16 esters were identified and quantified from the wine extracts by HS-SPME whereas by SBSE-LD technique were found 25 esters which include 2 higher alcohol acetates, 4 isoamyl esters and 19 ethyl esters of fatty acids. Generally SBSE-LD provided higher sensitivity with decreased analysis time.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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O efeito de dessecantes sobre o período anterior à interferência (PAI) pode auxiliar na tomada de decisão para o manejo das plantas daninhas. O objetivo desta pesquisa foi verificar se a adição de chlorimuron-ethyl ao glyphosate, para dessecação em pré-semeadura, altera a extensão do PAI na soja. O experimento foi realizado em Jaboticabal-SP, Brasil, submetendo-se o cultivar Monsoy 7908RR a oito períodos de convivência com plantas daninhas, além de testemunhas no mato e no limpo, nos quais foram aplicados dois grupos de tratamentos: glyphosate e glyphosate + chlorimuron-ethyl. em cada período, foram calculados o índice de importância relativa e os índices de diversidade e equitabilidade; por meio da análise de regressão dos dados de produtividade de grãos, determinou-se o PAI. Digitaria insularis, Acanthospermum hispidum, Raphanus raphanistrum e Commelina benghalensis apresentaram maior importância relativa. Os índices de diversidade e equitabilidade oscilaram durante os períodos, e a diferença entre as plantas daninhas fundamentou-se no acúmulo de massa seca. O PAI na soja no tratamento com glyphosate foi de 37 dias após a semeadura (DAS) e de 51 DAS naquele com glyphosate + chlorimuron-ethyl. A adição de chlorimuron-ethyl ao glyphosate permite que a cultura conviva mais tempo com as plantas daninhas sem que ocorra redução significativa na produtividade.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The aerial spraying of plant ripeners on sugar cane (Saccharum officinarum L.) crops causes often the contamination of neighboring areas, which subsidizes formal complaints from the neighbors. These contaminations are due to spraying taking place during inadequate environmental conditions or from technical mistakes during the application. One of the most important causes of this contamination is the susceptibility of the species being cultivated surrounding sugar cane. In order to evaluate the effects of sugar cane plant ripeners trinexapac-ethyl and sulfometuron-methyl on peanuts, cotton, potato, coffee, citrus, beans, sunflower, cassava, rubber, soybean, and grapes, eleven experiments - one for each species - were carried out from May 2009 to Jan. 2010. The field experiment was set according to a completely random design with five treatments and four replications. Just before or during flowering, a single treatment of trinexapac-ethyl at 100 or 200 g ha-1 and sulfometuron-methyl at 7.5 or 15 g ha-1 was applied to plants. A control treatment (plants not treated) for each species was part of each experiment. Trinexapac, at the doses of 100 and 200 g ha-1, showed selectivity to peanuts, cotton, potato, coffee, citrus, sunflower, cassava, rubber, soybean, and grape. At the lowest dose (100 g ha-1), it was selective for bean. Sulfometuron, at the dose of 7.5 g ha-1, was selective for peanuts and, at the two studied doses (7.5 and 15 g ha-1), it was selective for coffee, citrus, cassava, and rubber.
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Os reguladores de crescimento podem retardar o desenvolvimento vegetativo das plantas de gramas e, assim, reduzir a frequência de cortes; contudo, existem poucas informações referentes aos efeitos desses produtos sobre as estruturas da anatomia foliar. Dessa forma, o presente trabalho teve por objetivo avaliar os efeitos da aplicação sequencial de duas doses de trinexapac-ethyl sobre a anatomia foliar das espécies de gramas São Carlos (Axonopus compressus), Batatais (Paspalum notatum), Santo Agostinho (Stenotaphrum secundatum) e Esmeralda (Zoysia japonica). Os tratamentos utilizados foram constituídos de duas aplicações sequenciais de trinexapac-ethyl nas doses de 56,5+56,5 e 113,0+113,0 g ha-1; além de uma testemunha sem aplicação, para cada espécie avaliada. Os gramados foram cortados à altura de 3 cm, com auxílio de um aparador de grama motorizado, e, em seguida, foram realizadas as aplicações dos tratamentos. Após 20 dias da primeira aplicação de trinexapac-ethyl, as parcelas foram novamente aparadas à altura de 3 cm e foi realizada a segunda aplicação dos tratamentos. O delineamento experimental utilizado foi o de blocos ao acaso, com quatro repetições. Aos 70 dias após a segunda aplicação dos tratamentos, foram realizadas as amostragens do material foliar, para as quatro espécies estudadas. Os dados das variáveis quantitativas foram submetidos ao teste estatístico multivariado de análise de componentes principais. Os resultados evidenciaram a formação de três e dois grupos principais, para os caracteres da região da quilha (nervura mediana) e da região da asa (situada entre a nervura mediana e a margem do limbo foliar), respectivamente. de modo geral, em cada formação dos agrupamentos, os tratamentos com trinexapac-ethyl apresentaram maior similaridade entre si, em relação às respectivas testemunhas. Conclui-se que a aplicação sequencial de trinexapac-ethyl alterou algumas estruturas anatômicas da região da quilha e da asa do limbo foliar das espécies de gramas estudadas.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The analysis of alcoholic beverages for the important carcinogenic contaminant ethyl carbamate is very time-consuming and expensive. Due to possible matrix interferences, sample cleanup using diatomaceous earth (Extrelut) column is required prior to gas chromatographic and mass spectrometric measurement. A limiting step in this process is the rotary evaporation of the eluate containing the analyte in organic solvents, which is currently conducted manually and requires approximately 20-30 min per sample. This paper introduces the use of a parallel evaporation device for ethyl carbamate analysis, which allows for the simultaneous evaporation of 12 samples to a specified residual volume without manual intervention. A more efficient and, less expensive analysis is therefore possible. The method validation showed no differences between the fully-automated parallel evaporation and the manual operation. The applicability was proven by analyzing authentic spirit samples from Germany, Canada and Brazil. It is interesting to note that Brazilian cachacas had a relatively high incidence for ethyl carbamate contamination (55% of all samples were above 0.15 mg/l), which may be of public health relevance and requires further evaluation.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This study compared the fixation of autogenous onlay bone grafts with cyanoacrylate glue (Super Bonder) and with titanium screws. Twenty rabbits underwent bilateral parietal ostectomies. Bone segments were fixed anteriorly to the resulting bone defect. In group I, the grafts were fixed with 4 min long, 1.5 mm diameter screws; in group II, adhesive was used. The animals were killed after 5, 15, 30, 60 and 120 days. Histomorphometric analysis was used to quantify the maintenance of the graft area. Discrete areas of inflammatory reaction were seen in both groups after 5 days and for group II after 15 days. After 30 days, new bone formation was seen at the interface of the grafts. After 120 days, the graft was incorporated into the host bed in group I and partially incorporated in group II. There was a significant statistical difference regarding the mean graft areas between 15 and 120 days (p < 0.001) and between fixation methods (p < 0.002). Fixation with adhesive promoted a significantly greater area of bone graft than screw fixation, independent of time period. The adhesive was biocompatible, presented similar stability to the screw and maintained the bone area, although there was a delay in graft incorporation.
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O presente trabalho teve como objetivo avaliar os efeitos da aplicação de duas doses de trinexapac-ethyl sobre a morfologia das espécies de gramas São Carlos (Axonopus compressus), Batatais (Paspalum notatum), Santo Agostinho (Stenotaphrum secundatum) e Esmeralda (Zoysia japonica). Os gramados foram cortados à altura de 3 cm no início do experimento e 20 dias depois. Após cada corte, foram realizadas duas aplicações sequenciais de trinexapac-ethyl nas doses de 56,5 + 56,5 e 113,0 + 113,0 g ha-1 , além de uma testemunha sem aplicação, para cada espécie avaliada. O delineamento experimental utilizado foi o de blocos ao acaso com quatro repetições. A redução do crescimento foi avaliada por meio da altura das plantas. Semanalmente, o número e altura de inflorescências foram avaliados por amostragem, realizada em 0,25 m² no centro das parcelas; no final do experimento, avaliou-se a massa seca total. A aplicação do trinexapac-ethyl retardou o crescimento vegetativo e a emissão das inflorescências, assim como não provocou danos aparentes nos gramados. O uso do trinexapac-ethyl nos gramados avaliados pode reduzir a necessidade de cortes em até 55 dias após a segunda aplicação.