A ocorrência das doenças foliares de final de ciclo em soja (Glycine max) causadas pelos fungos Septoria glycines e Cercospora kikuchii é facilmente observada no campo. Entretanto, são necessárias informações precisas sobre a quantificação de danos e perdas na produtividade. A falta de um método padrão de quantificação visual para essas doenças pode levar a estimativas imprecisas da severidade das mesmas, induzindo a conclusões erradas. Com o objetivo de elaborar uma escala diagramática para quantificar a severidade dessas doenças, foram coletadas em campo, folhas apresentando diferentes níveis de severidade. A área de cada folha e sua correspondente severidade foram determinadas e, obedecendo-se a "Lei do estímulo de Weber-Fechner", foi elaborada uma escala com os níveis de severidade de doença: 2,4; 15,2; 25,9; 40,5 e 66,6%. A validação foi realizada por nove avaliadores, sem experiência na avaliação das doenças de final de ciclo, os quais estimaram a severidade de 30 folhas de soja com sintomas destas doenças. A precisão das avaliações variou de acordo com o avaliador (0,84<R²<0,65), bem como a acurácia (0,00<a<3,40; 0,90<b<1,29), não ocorrendo erro sistemático na superestimativa ou subestimativa da doença entre os avaliadores, demonstrando que a escala desenvolvida é adequada para a avaliação das doenças de final de ciclo em soja.
Studies suggest that silicic acid or silica can reduce the oral absorption and increase the excretion of aluminum thus protecting the organism against the adverse effects induced by this metal. Therefore, the simultaneous or concomitant determination of Al and Si in biological samples is of significance. In this study a method for sample treatment and the determination of both Al and Si by graphite furnace atomic absorption spectrometry (GFAAS) in animal tissue was developed. Sample dissolution with tetramethylammonium hydroxide (TMAH) proved to be suitable for the determination of both elements.Because Si enhances the Al signal during atomization, this element acted as a chemical modifier for the determination of Al. For the determination of Si, palladium nitrate was the most suitable modifier. The use of Zr as a permanent modifier minimized the tube degradation caused by TMAH. The limits of detection were 5.8 mg L À1 for Al and 29.0 mg L À1 for Si, and the recoveries in spiked samples were between 97 and 112%. The method was validated against bovine liver standard reference materials (SRM 1577b and 1577c), and the obtained concentrations agreed with the certified values.
Flexible medical devices are primarily made of plasticized polyvinyl chloride (PVC). Lately, PVC is being replaced with ethyl vinyl acetate (EVA) and polypropylene (PP) to avoid undesired migration of the PVC plasticizers. Nevertheless, other additives are necessary to generate useful polymeric materials. Metallic species present in such additives can also leach out into the infusion solutions. The migration of Ba, Cd, Sn, Pb, and Zn from devices made from PVC, EVA, and PP was evaluated. Bags and infusion sets were decomposed, and their metallic contents were analyzed. Glucose, NaCl, and Tween 80 were investigated as extraction media. These solutions were stored in PVC, EVA, and PP bags, heat sterilized, and stored for eight months at room temperature. Aliquots were taken before and after sterilization and then once per month to determine the contents of the metals. Commercial glucose and NaCl infusions were analyzed by taking aliquots of the solutions from the bags and from the administration set after their administration to patients. The three polymers contained the five metals. Ba was found in the highest concentration in all samples, with a mean of 8.0 mg/kg in PVC, 4.2 mg/kg in EVA, and 4.7 mg/kg in PP samples. Despite this, the only element that migrated into the glucose, NaCl, and Tween 80 solutions was Zn. The same result was found for the commercial glucose and NaCl infusions. Moreover, the Zn concentration in the administration sets was on average 52% higher than what was found in the bags.
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