Pré-concentração de compostos fenólicos de matrizes ambientais empregando método de microextração por solvente e quantificação por cromatografia a líquido

Orientador: Prof. Dr. Gilberto AbateCoorientadora: Profa. Dra. Iara MesserschmidtTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Química. Defesa : Curitiba, 27/02/2015Inclui referências: p.102-108Resumo: Neste trabalho foi investigado o desenvolvimento de metodo analitico empregando microextracao por solvente (SME) para extracao e pre-concentracao de fenol (Ph), o-Cresol (o-Cr), m-Cresol (m-Cr), p-Cresol (p-Cr) e 2,4-dimetil-fenol (2,4- DMF), visando a quantificacao em amostras aquosas e extrato de solo previamente condicionado com xisto retortado (XR). As quantificacoes foram realizadas por cromatografia a liquido com deteccao por arranjo de diodos (LC-DAD), fase movel composta por acetonitrila:acido acetico 1,0 % (40:60), vazao de 1,00 mL min-1, por eluicao isocratica, coluna C18 (25 x 0,46 cm, 5 _m) a 40,0 oC, volume de injecao de 20,0 _L e deteccao em comprimento de onda de 270 nm. Depois da avaliacao de alguns procedimentos baseados em SME, foi proposta uma estrategia de extracao em duas etapas (two-step SME), utilizando um balao volumetrico como frasco de extracao. Na primeira etapa foi feita a extracao com n-octanol, seguido por um segundo passo usando solucao de NaOH como uma fase aceptora. As condicoes de extracao como tipo de solvente extrator, volume de solvente, volume de amostra, pH, temperatura, tempo de agitacao, efeito da forca ionica, volume e concentracao de solucao aceptora de NaOH foram cuidadosamente investigadas de forma univariada e de modo multivariado por planejamento fatorial de experimentos fracionado 25-1. De acordo com os resultados do planejamento fatorial nao foram observadas interacoes significativas entre as variaveis testadas, sendo que os efeitos mais importantes foram as concentracoes de NaOH e NaCl e volume de n-octanol. Com base nos dois estudos as melhores condicoes de extracao foram: 900 _L de n-octanol como solvente, NaOH 0,60 mol L-1 como fase aceptora, tempo de extracao de 5,0 min, HCl 0,01 mol L-1 e NaCl 15,0 % na fase doadora, e 20,0 °C como temperatura de extracao. Sob estas condicoes e utilizando 50,0 mL de amostra, o metodo apresentou limite de deteccao entre 0,3 e 3,5 _g L-1, limite de quantificacao entre 1,2 e 10,6 _g L-1, intervalo linear de 2,50 a 50,0 _g L-1 (Ph, o-Cr, m-Cr+p-Cr) e entre 12,5 e 250,0 _g L-1 (2,4-DMF). O metodo proposto, two-step SME foi aplicado com sucesso para a determinacao dos compostos alvo em amostras aquosas de agua da torneira, agua de rio, agua subterranea, agua do mar e um extrato aquoso obtido de um solo condicionado com XR. Foram observados resultados de recuperacao de 72,5 a 126,0 % e desvio padrao relativo entre 0,3 e 11,5 %, sugerindo a utilizacao do metodo para a quantificacao de compostos fenolicos polares em amostras aquosas, com exatidao e precisao adequadas. Palavras-chave: Compostos fenolicos. Microextracao por solvente. Cromatografia a liquido. Xisto retortado. Solo.Abstract: In the present work a solvent microextraction method (SME) was investigated for the extraction and preconcentration of phenol (Ph), o-Cresol (o-Cr), m-Cresol (m-Cr), p-Cresol (p-Cr) e 2,4-dimethylphenol (2,4-DMP), aiming the quantification in aqueous samples and in a soil extract from a soil previously conditioned with retorted shale (RS). Liquid chromatography with diode-array detector (LC-DAD) was employed with mobile phase composed by acetonitrile:1,0 % acetic acid (40:60), flow rate 1.00 mL min-1 under isocratic elution, column C18 (25 x 0.46 cm, 5 _m) at 40.0 oC, volume of injection 20.0 _L, and detection in the wavelength of 270 nm. Some SME procedures were evaluated, and after that, the approach of two-step SME was proposed using a volumetric flask as an extraction flask. In the first step an extraction using n-octanol was made, followed by the second step of extraction by NaOH as an acceptor phase. All the extraction conditions as kind of extraction solvent, solvent volume, sample volume, pH, temperature, stirring time, ionic strength effect, volume and concentration of the NaOH as acceptor solution were thoroughly investigated by univariate study and using multivariate fractional design of experiments 25-1. The results of factorial design indicated no significant interactions between the variables, and the more important effects were the NaOH and NaCl concentrations and n-octanol volume. Based on both studies, the best conditions of microextraction were: 900 _L of n-octanol as solvent, 0.60 mol L-1 NaOH as acceptor phase, extraction time of 5.0 min, 0.01 mol L-1 HCl and 15.0 % NaCl in the donor phase, and 20.0 °C as temperature of extraction. Using these conditions and 50.0 mL of sample volume, the method presented limit of detection between 0.3 and 3.5 _g L-1, limit of quantification between 1.2 and 11.6 _g L-1, linear range from 2.50 to 50.0 _g L-1 (Ph, o-Cr, m-Cr+p-Cr) and between 12.5 and 250.0 _g L-1 (2,4-DMP). The proposed method two-step SME was successfully employed for determination of the target compounds in aqueous samples of tap water, river water, groundwater, sea water and an aqueous extract from a soil (Ultisol) conditioned with RS. Recovery results from 72.5 to 126.0 % and relative standard deviation between 0.3 and 11.5 % were observed, suggesting the use of the method for the quantification of polar phenolic compounds in aqueous samples, with appropriate accuracy and precision. Keywords: Phenolic compounds. Solvent Microextraction. Liquid chromatography. Retorted Shale. Soil

Comparison of Natural Feature Descriptors for Rigid-Object Tracking for Real-Time Augmented Reality

This paper presents a comparison of natural feature descrip- tors for rigid object tracking for augmented reality (AR) applica- tions. AR relies on object tracking in order to identify a physical object and to superimpose virtual object on an object. Natu- ral feature tracking (NFT) is one approach for computer vision- based object tracking. NFT utilizes interest points of a physcial object, represents them as descriptors, and matches the descrip- tors against reference descriptors in order to identify a phsical object to track. In this research, we investigate four different nat- ural feature descriptors (SIFT, SURF, FREAK, ORB) and their capability to track rigid objects. Rigid objects need robust de- scriptors since they need to describe the objects in a 3D space. AR applications are also real-time application, thus, fast feature matching is mandatory. FREAK and ORB are binary descriptors, which promise a higher performance in comparison to SIFT and SURF. We deployed a test in which we match feature descriptors to artificial rigid objects. The results indicate that the SIFT de- scriptor is the most promising solution in our addressed domain, AR-based assembly training

Latín y multilingüismo a través de un proyecto europeo

In this article we aim to make public the eTwinning project which fi ve secondary schools in different towns, Barreiro in Portugal and Basauri, Bilbao, Soria and Siles in Spain, have carried out in the subject of Latin of 10th or/and 11th year. The selectedtopic for the project was the Romanisation of the Iberian Peninsula. The motivation for carrying it out was to apply the use of new technologies to the teaching of some cultural contents through a cooperative methodology with students of other schoolsand to promote the use of both Latin and English. The article will explicitly state the project’s aims, the plan and link with the syllabus of the subject of Latin in 10th year, the implementation and sequencing of tasks, the assessment system and the results:the progress in academic achievement and the feedback received by the students. Moreover, the advantages and disadvantages found in the development of such a project as a whole will be discussed. Finally, the recognition received from the eTwinningSupport Service in the form of the Spanish Quality Label will be mentioned, in the hope of receiving the Portuguese and the European ones. En este artículo pretendemos dar a conocer el proyecto eTwinning que hemos llevado a cabo cinco institutos de localidades distintas: Barreiro (Portugal), Basauri (País Vasco), Bilbao (ídem), Soria (Castilla y León) y Siles (Andalucía), para la asignatura de Latín de 4º de ESO y/o 1º de Bachillerato. El tema escogido para el proyecto fue la Romanización de la Península Ibérica. La motivación para llevarlo a cabo fue la de aplicar las nuevas tecnologías a la impartición de una serie de contenidos culturalesa través de una metodología cooperativa con alumnos de otros centros educativos y fomentar, a su vez, el uso tanto del latín como del inglés. En nuestro trabajo explicitaremos los objetivos del proyecto, la planificación del mismo y la vinculación conla programación didáctica de la asignatura de Latín de 4º de ESO, la implementación y secuenciación del proyecto, el sistema de evaluación, los logros conseguidos en el rendimiento académico y la retroalimentación recibida de los alumnos. Asimismo, secomentarán tanto las ventajas como las dificultades encontradas en la gestación y desarrollo de tal proyecto en su conjunto. Por último, se mencionará el reconocimiento por parte del Servicio de Apoyo de eTwinning a la labor desempeñada a través de laconcesión del sello nacional y a la espera del sello portugués y europeo

Rigid Object Tracking Algorithms for Low-Cost AR Devices

Augmented reality (AR) applications rely on robust and efficient methods for tracking. Tracking methods use a computer-internal representation of the object to track, which can be either sparse or dense representations. Sparse representations use only a limited set of feature points to represent an object to track, whereas dense representations almost mimic the shape of an object. While algorithms performed on sparse representations are faster, dense representations can distinguish multiple objects. The research presented in this paper investigates the feasibility of a dense tracking method for rigid object tracking, which incorporates the both object identification and object tracking steps. We adopted a tracking method that has been developed for the Microsoft Kinect to support single object tracking. The paper describes this method and presents the results. We also compared two different methods for mesh reconstruction in this algorithm. Since meshes are more informative when identifying a rigid object, this comparison indicates which algorithm shows the best performance for this task and guides our future research efforts

Viscum album mother tinctures: Harvest conditions and host trees influence the plant metabolome and the glycolytic pathway of breast cancer cells.

Viscum album is a semi-parasitic plant used for over one hundred years in complementary cancer therapy. The main commercial drugs used in cancer patients' treatment are derived from the aqueous V. album extracts, whose cytotoxic potential is mostly attributed to the aqueous soluble antitumoral metabolites. On the counterpart, ethanol solvents must be used to obtain V. album mother tinctures. This methodology permits better solubilization of phenolic compounds, among others, which present antitumoral bioactivity. Recently, the metabolomics approach revealed the influence of the host tree on the V. album subspecies differentiation. To increase the scientific information about the chemical differences related to the host trees and to clarify the seasonal influences, in this study, the metabolome of 50 V. album mother tinctures from three subspecies (abietis, album, austriacum) and five host trees (Malus domestica, Quercus sp., Ulmus carpinifolia, Pinus sylvestris, Abies alba) was evaluated using summer and winter plant harvests. The in vitro cytotoxic activities were investigated in breast cancer cells (MDA-MB-231) and immortalized normal human keratinocytes (HaCaT). The summer V. album mother tinctures presented higher cytotoxic activity than winter ones. Among the summer samples, those prepared with V. album subsp. album were more cytotoxic than V. album subsp. abietis and subsp. V. album subsp. austriacum. The V. album harvested from Quercus petraea and Abies alba inhibited the key-glycolytic enzymes: hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK). This activity was related to a reduction in glucose uptake and lactate production, which were host-tree-time-dose-dependent. The untargeted metabolomic approach was able to discriminate the mother tinctures according to respective botanical classes and harvest season. A total of 188 metabolites were annotated under positive and negative modes. Fourteen compounds were responsible for the samples differentiation, and, to the best of our knowledge, eight were described in the Viscum album species for the first time. Our study shows the interruption of the Warburg effect as a novel antitumoral mechanism triggered by V. album mother tinctures, which is related to their metabolite profile. These results bring scientific evidence that encourages the use of V. album mother tinctures as a natural product for cancer therapy

Difference between preferred and non-preferred leg in peak speed, acceleration, and deceleration variables and their relationships with the change-of-direction deficit

The aim of this study was two-fold: (i) analyze the variation of kinematic measures between using preferred and non-preferred legs while braking during the 5–0–5 change of direction test; and (ii) test the relationships between kinematic measures, and change-of-direction deficit (CODD). A cross-sectional study using twenty adult male soccer players (21.6 ± 2.0 years; 73.2 ± 6.1 kg; 174.8 ± 4.5 cm) was employed. Players performed three repetitions of the 5–0–5 test using each leg during the braking phase. Players have used the Polar Team Pro to obtain the kinematic measures of peak speed, peak acceleration, and peak deceleration. Additionally, the CODD was also obtained using single-beamed photocells. Comparisons revealed a significantly greater peak acceleration (+ 0.22 m/s2; p < 0.001) and deceleration (+ 0.17 m/s2; p = 0.004) for the non-preferred leg. There were no significant correlations were found between CODD and peak accelerations (r = − 0.014, [− 0.193; 0.166]), peak decelerations (r = − 0.052, [− 0.229; 0.128]) or peak speed (r = 0.118, [− 0.063; 0.291]). This study revealed that preferred and non-preferred leg must be analyzed differently since they are different in the kinematic variables. However, CODD seems independent of leg preference and the kinematic measures of a 5–0–5 change of direction test.info:eu-repo/semantics/publishedVersio

Marketing de relacionamento no setor de ensino superior: a percepção dos alunos de uma faculdade da serra gaúcha

Resumo: O marketing de relacionamento pode ser visto como ferramenta importante para melhorar a relação entre instituições de ensino superior e alunos. Esse estudo teve como objetivo analisar a percepção do nível de relacionamento dos alunos com uma faculdade do Rio Grande do Sul. Para tanto foi utilizada a a abordagem quantitativa com a adaptação e revalidação da escala de Wilson e Vlosky (1997). Os resultados indicaram uma percepção razoável do relacionamento. Como ponto positivo as dimensões que obtiveram maior média foram às mencionadas por Morgan e Hunt (1994) como sendo chave para construção e manutenção de relacionamentos duradouros, sendo elas: comprometimento e confiança. Os itens da escala de Wilson e Vlosky (1997) que mais influenciaram na avaliação do relacionamento dizem respeito ao esforço e investimento aplicado para o relacionamento, seguido pela percepção de parceria com a instituição e expectativa de relacionamento por longo tempo

Comparing Visual Assembly Aids for Augmented Reality Work Instructions

Increased product complexity and the focus on zero defects, especially when manufacturing complex engineered products, means new tools are required for helping workers conduct challenging assembly tasks. Augmented reality (AR) has shown considerable promise in delivering work instructions over traditional methods. Many proof-of-concept systems have demonstrated the feasibility of AR but little work has been devoted to understanding how users perceive different AR work instruction interface elements. This paper presents a between-subjects study looking at how interface elements for object depth placement in a scene impact a user’s ability to quickly and accurately assemble a mock aircraft wing in a standard work cell. For object depth placement, modes with varying degrees of 3D modeled occlusion were tested, including a control group with no occlusion, virtual occlusion, and occlusion by contours. Results for total assembly time and total errors indicated no statistically significant difference between interfaces, leading the authors to conclude a floor has been reached for optimizing the current assembly when using AR for work instruction delivery. However, looking at a handful of highly error prone steps showed the impact different types of occlusion have on helping users correctly complete an assembly task. The results of the study provide insight into how to construct an interface for delivering AR work instructions using occlusion. Based on these results, the authors recommend customizing the occlusion method based on the features of the required assembly task. The authors also identified a floor effect for the steps of the assembly process, which involved picking the necessary parts from tables and bins. The authors recommend using vibrant outlines and large textual cues (e.g., numbers on parts bins) as interface elements to guide users during these types of “picking” steps

Chemical recycling of polyethylene by tandem catalytic conversion to propylene

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