Simultaneous Measurement Of Electrical And Thermal Properties: Application To Margarine

An experimental set-up for simultaneous measurement of thermal and dielectric properties of pasty materials, and in particular of margarine is proposed. The objective of the study was to observe simultaneously how the above mentioned properties change when margarine undergoes temperature changes within a temperature range that also encompasses its melting point. The PVDF pyroelectric sensor in combination with the plane plate capacitor was used for simultaneous measurement avoiding thereby problems arising from differences in both, sample's quantity and specific portion taken, the illumination level, heating, etc. As result of temperature variations both, the electrical and thermal properties of margarine were shown very sensitive to the structural changes. The reversibility of the modification process was observed. The results obtained with the set-up for simultaneous measurements were compared to those acquired by the methods capable of measuring each of the two properties separately. © EDP Sciences.125849852Pudney, P.D.A., Hancewicz, T.M., Cunningham, D.G., (2002) Spectrosc-int J, 16, p. 217Van Dalen, G., (2002) J Microsc-oxford, 208 (2), p. 116Benzo, Z., Marcano, E., Gomez, C., (2002) J AOAC Int, 85 (4), p. 967Sacchi, R., Addeo, F., Musso, S.S., (1995) Ital J Food Sci, 7 (1), p. 27Dadarlat, D., Gibkes, J., Bicanic, D., (1996) J Food Eng, 30 (1-2), p. 155De Pereira, J.R., Da Silva, E.C., Mansanares, A.M., Miranda, L.C.M., (2001) Analytical Sci., 17, p. 172Longuemart, S., Quiroz, A.G., Dadarlat, D., Sahraoui, A.H., Kolinsky, C., Buisine, J.M., Da Silva, E.C., Neamtu, C., (2002) Instrum. Sci. Technol., 30 (2), p. 157Dadarlat, D., Bicanic, D., Gibkes, J., (1996) Chem. Phys. Lipids, 82 (1), p. 15Marinelli, M., Mercuri, F., Zammit, U., Pizzoferrato, R., Scudieri, F., Dadarlat, D., (1994) Phys. Rev. B, 49, p. 9523Dadarlat, D., Chirtoc, M., Neamtu, C., Candea, R., Bicanic, D., (1990) Phys. Stat. Sol.(a), 121, pp. K23

Epidemiological survey of dermatophytosis in meat rabbits with alopecia in Portugal

[EN] An epidemiological dermatophytosis survey was carried out in farmed rabbits with alopecia in Northern and Central Portugal. Between August and October 2008, samples from suspected clinical cases of alopecia in meat rabbits on industrial farms were collected and cultured by conventional methods. Effects on the prevalence of several variables, such as breed, age, month of sample collection, configuration of the lesions and presence of concomitant infections in the rabbitries were evaluated using a logistic regression model. The overall prevalence of dermatophytes species was 82.7% (95% CI: 80.1-85.3%). Two dermatophytes species were isolated: Trichophyton mentagrophytes (91.9%) and Microsporum canis (8.1%). Five variables were associated with dermatophyte isolation in univariate analysis. The multivariate logistic regression model identified configuration of lesions (OR=3.15; 95% CI: 1.39-7.15%) and the presence of concomitant infections on the farms (OR=2.71; 95% CI: 1.03-7.12%) as risk factors. Considering the paucity of epidemiological reports in this country, these results could make a useful contribution towards the diagnosis and prevention of rabbit dermatophytosis.Moreira, F.; Miranda, A.; Coelho, A.; Monteiro, J.; Coelho, A. (2012). Epidemiological survey of dermatophytosis in meat rabbits with alopecia in Portugal. World Rabbit Science. 20(1):43-48. doi:10.4995/wrs.2012.1032SWORD434820

Satisfação e retenção de praticantes em contexto universitário: estudo de caso das atividades aquaticas do programa UPFIT

A qualidade do serviço tem sido referida como determinante para satisfação do consumidor, que por sua vez é decisiva na sua retenção no consumo de um serviço. A satisfação resulta habitualmente da avaliação feita pelo consumidor sobre o serviço adquirido com base nas suas necessidades e expectativas, resultando num sentimento de satisfação ou insatisfação. O estudo da satisfação do consumidor poderá dar à instituição indicações válidas sobre a sua intenção futura de retenção que, por sua vez, influenciará o desempenho financeiro da instituição. Na indústria do desporto, esta realidade é ainda mais vincada devido às baixas taxas de retenção que a caraterizam. Especificamente na natação, uma das modalidades de eleição dos portugueses, este estudo da satisfação do consumidor é ainda mais preponderante, já que as piscinas são infraestruturas de gestão complexa, que deverá ser eficiente garantindo a sua sustentabilidade, e justificando o investimento efetuado na sua construção. O presente estudo surge exatamente na necessidade de melhorar continuamente a qualidade dos serviços prestados nas atividades aquáticas do Programa de Fitness da UPorto, conhecendo-se cada vez mais os comportamentos de consumo dos utentes, e tendo como objetivo a gestão eficaz dos recursos visando reter o utente. Neste sentido, o objetivo principal do presente estudo consiste em efetuar uma análise comparativa da satisfação sobre a qualidade do serviço (limpeza e arrumação, temperatura, manutenção, técnicos, e aulas) e retenção (razões para não frequentarem mais; recomendação; e aspetos a melhorar para aumento dos serviços) dos utentes das atividades aquáticas do Programa de Fitness da UPorto, em 2015 e 2016.Foi aplicado um questionário, em dois momentos distintos (2015 e 2016), no Programa de Fitness da UPorto, a 151 utentes (52 e 99, em 2015 e 2016, respetivamente) que frequentam as atividades aquáticas. O questionário de 7 questões foi inicialmente desenvolvido para responder a questões da prática da gestão e posteriormente revisto por dois professores universitários que adequaram a estrutura e conteúdo. Os resultados obtidos permitiram concluir que a satisfação dos utentes com a imagem e simpatia dos técnicos aumentou. Todavia, a satisfação com a limpeza da piscina, temperatura ambiente da piscina e balneários, tratamento da água da piscina, atendimento dos rececionistas, feedbacks e dinamismo durante as aulas, e utilização do material pelos professores diminuiu de 2015 para 2016. Este estudo permitiu ainda concluir na análise da retenção, que nenhum dos itens avaliados parece ser a causa de menor assiduidade dos utentes; que de forma global que “não há nada a melhorar” nas atividades aquáticas; e que todos os utentes avaliados, têm a intenção de aconselhar as atividades aquáticas a um amigo/familiar.info:eu-repo/semantics/publishedVersio

SPATIO-TEMPORAL VARIATION OF METAL CONCENTRATIONS IN ESTUARINE ZONES OF THE TODOS OS SANTOS BAY, BAHIA, BRAZIL: Variação espaço-temporal das concentração de metais em zonas estuarinas da Baía de Todos os Santos, Bahia, Brasil

The knowledge of metal behavior in the aquatic environment is important for understanding its effects in estuarine zones and mangrove areas. These important and precious ecosystems are affected by many different factors that may vary temporally and spatially. The present study investigated the spatial and temporal variation of physicochemical parameters (pH, dissolved oxygen, temperature, salinity, etc.) and metal concentrations (Zn, Fe, Ni, Cu) at three different locations along the Todos os Santos Bay, North East Brazil, by analyzing surface water, sediment and mangrove oysters (Cassostrea rhizophorae (Guildin, 1828)). Metal concentrations in surface waters and sediments differed between the three sampling times (March and August 2014; January 2015) and locations and were affected by fluctuating physicochemical parameters, which in this way also affected the metal bioconcentration in the oysters. The pH of the surface waters, for example, increased from the 1st to the 3rd sampling time while the concentrations of Zn and Fe decreased during the same period. The sediment concentrations of Zn and Fe were strongly correlated with organic matter content. These results suggests that seasonality as well as the different water and sediment properties along the bay directly affect metal concentration and bioavailability in the environment.O conhecimento do comportamento de metais no meio aquático é importante para a compreensão dos seus efeitos em zonas estuarinas e nas áreas de manguezais. Esses importantes e preciosos ecossistemas são afetados por muitos diferentes fatores que podem variar temporalmente e espacialmente. O presente estudo investigou a variação espacial e temporal de parâmetros fisicoquímicos (pH, oxigênio dissolvido, temperatura, salinidade, etc.) e as concentrações de metais (Zn, Fe, Ni, Cu) em três locais diferentes ao longo da Baía de Todos os Santos, Nordeste Brasil, analisando as águas superficiais, os sedimentos e as ostras de manguezal (Cassostrea rhizophorae (Guildin, 1828)). As concentrações de metais em águas superficiais e sedimentos diferiram entre os três tempos e locais de amostragem (março e agosto de 2014, janeiro de 2015) e foram afetados por parâmetros fisicoquímicos flutuantes, o que também afetou a bioconcentração de metal nas ostras. O pH das águas superficiais, por exemplo, aumentou do 1º ao 3º tempo de amostragem, enquanto as concentrações de Zn e Fe diminuíram durante o mesmo período. As concentrações de sedimentos de Zn e Fe foram fortemente correlacionadas com o teor de matéria orgânica. Esses resultados sugerem que a sazonalidade, bem como as diferentes propriedades de água e sedimentos ao longo da baía, afetam diretamente a concentração e a biodisponibilidade do metal no meio ambiente

HPLC- MS Flavonoid determination and antioxidant capacity of Brazilian dehydrated bee pollen

Bee-pollen, produced by Apis mellifera bees, is an important source of proteins, lipids, vitamins and minerals for the hive, being considered one of nature's most completely nourishing foods. Its composition may vary according to the geographical region and its quality is influenced by harvest method and processing conditions. Although it has good nutritional components, beepollen contains significant amounts of polyphenols with recognized health benefits, including antioxidant activity. The present study aimed to evaluate the flavonoid composition, using HPLC-MS technique; and the antioxidant activity, using two different methods (DPPH and ORAC), of eight dehydrated bee-pollen samples collected in different Brazilian apiaries. The sample with the highest antioxidant capacity using DPPH method was produced in Rio Grande do Sul State (110.85 mol TE/g) while the sample with the least antioxidant capacity was collected in Bahia State (9.97 mol TE/g). The same sample from Rio Grande do Sul State presented the highest antioxidant capacity using ORAC method (542.00 mol TE/g), while the lowest value was observed in a sample from Mato Grosso State (133.70 mol TE/g). The flavonoid analysis using HPLC-MS revealed the following variations: catechin (0.69 to 0.75 mg/100 g); naringenine (4.57 to 18.36 mg/100 g); rutin (3.36 to 46.80 mg/100 g); quercetin (1.86 to 67.91 mg/100 g) and kaempferol (5.50 to 44.97 mg/100 g). In the sample with the highest antioxidant capacity (Rio Grande do Sul State) was observed 40 peaks in the HPLC-MS, while the samples with the lowest antioxidant capacities the number of peaks were 25 (Mato Grosso State) and 22 (Bahia State); therefore, the variety of compounds may have influenced the antioxidant capacity of the samples.info:eu-repo/semantics/publishedVersio

Path-flow analysis model for anthropometric, hydrodynamic and biomechanical variables in age-group swimmers

The goal of competitive swimming is to travel the event distance as fast as possible. The identification of the parameters that predict swimming performances is one of the main aims of the swimming “science” community

Path-flow analysis model for anthropometric, hydrodynamic and biomechanical variables in age-group swimmers

The aim of this research was to develop a path-flow analysis model for age-group swimmer’s speed based on anthropomeric, hydrodynamic and biomechanical determinants

Sulphonamide-imprinted sol–gel materials as ionophores in potentiometric transduction

This work proposes different kind of solid-contact graphite-based electrodes for the selective determination of sulphonamides (SPHs) in pharmaceuticals, biological fluids and aquaculture waters. Sulfadiazine (SDZ) and sulfamethoxazole (SMX) were selected for this purpose for being the most representative compounds of this group. The template molecules were imprinted in sol–gel (ISG) and the resulting material was used as detecting element. This was made by employing it as either a sensing layer or an ionophore of PVC-based membranes and subsequent potentiometric transduction, a strategy never reported before. The corresponding non-imprinted sol–gel (NISG) membranes were used as blank. The effect of plasticizer and kind/charge of ionic lipophilic additive was also studied. The best performance in terms of slope, linearity ranges and signal reproducibility and repeatability was achieved by PVC membranes including a high dielectric constant plasticizer and 15 mg of ISG particles. The corresponding average slope was −51.4 and −52.4 mV/decade, linear responses were 9.0 × 10−6 and 1.7 × 10−5 M, and limits of detection were 0.74 and 1.3 μg/mL for SDZ and for SMX, respectively. Good selectivity with log Kpot < −0.3 was observed for carbonate, chloride, fluoride, hydrogenocarbonate, nitrate, nitrite, phosphate, cyanide, sulfate, borate, persulphate, citrate, tartrate, salicylate, tetracycline, ciprofloxacin, sulphamerazine, sulphatiazole, dopamine, glucose, galactose, cysteine and creatinine. The best sensors were successfully applied to the analysis of real samples with relative errors ranging from −6.8 to + 3.7%

Force Spectroscopy And Two Photon Excited Luminescence In An Optical Tweezers System

Up to now optical spectroscopies have analyzed the scattered light or the heat generated by absorption as a function of the wavelength to get information about the samples. Among the light matter interaction phenomena one that has almost never been used for spectroscopy is the direct photon momenta transfer. Probably because the forces involved are very small, varying from hundreds of femto to tens of pico Newtons. However, the nowadays very popular Optical Tweezers can easily accomplish the task to measure the photon momenta transfer and may be the basis for the Optical Force Spectroscopy. We demonstrate its potential as such a tool by observing more than eight Mie resonance peaks of a single polystyrene microsphere, and showed the capability to selective couple the light to either the TE, TM or both microsphere modes depending of the beam size, the light polarization and the beam positioning. The Mie resonances can change the optical force values by 30-50%. Our results also clearly show how the beam polarization breaks the usually assumed azimuthal symmetry by Optical Tweezers theories. We also obtained the spectrum from the two photon excited luminescence using the Optical Tweezers to hold a single bead suspended and a femtosecond Ti:sapphire laser for the non-linear excitation. This spectrum shows the pair of peaks due to both TE and TM spherical cavity modes. We have been able to observe more than 14 Mie resonance peaks in the TPE luminescence. Our results are in good agreement with optical force calculations using Maxwell stress tensor and partial wave decomposition of the incident beam approximated to a 3th order gaussian beam.593017Ashkin, Dziedzic, J.M., Bjorkholm, J.E., Chu, S., Observation of a single-beam gradient force trap for dielectric particles (1986) Opt. Lett., 11, pp. 288-290Ashkin, A., Dziedzic, J.M., Optical trapping and manipulation of viruses and bacteria (1987) Science, 235, pp. 1517-1520Grier, D.G., A revolution in optical manipulation (2003) Nature, 424, pp. 810-816Felgner, H., Frank, R., Schliwa, M., Flexural rigidity of microtubules measured with the use of optical tweezers (1996) J. Cell Sci., 109, pp. 509-516Sakata-Sogawa, K., Kurachi, M., Sogawa, K., Fujii-Kuriyama, Y., Tashiro, H., Direct measurement of DNA molecular length in solution using optical tweezers: Detection of looping due to binding protein interactions (1998) Eur. Biophys. J., 27, pp. 55-61Berg, H.C., Berry, R.M., Absence of a barrier to backwards rotation of the bacterial flagellar motor demonstrated with optical tweezers (1997) Proc. Natl. Acad. Sci. U.S.A., 94, pp. 14433-14437Huruta, R.R., Mechanical properties of stored red blood cells using optical tweezers (1998) Blood, 92, pp. 2975-2977Brandão, M.M., Optical tweezers for measuring red blood cell elasticity: Application to the study of drug response in sickle cell disease (2003) Eur. J. Haematol., 70, pp. 207-211Ashkin, A., Dziedzic, J.M., (1977) Phys. Rev. Lett., 38, pp. 1351-1355Barber, P.W., Chang, R.K., (1988) Optical Effects Associated with Small Particles, , Word Scientific, SingaporeVan De Hulst, H.C., (1981) Light Scattering by Small Particles, , Dover, New YorkAshkin, A., Dziedzic, J.M., Observation of optical of dieletric particles by light-scattering (1981) Appl. Optics, 20, pp. 1803-1814Benner, R.E., Barber, P.W., Owe, J.F., Chang, R.K., Observation of structure resonances in the fluorescence spectra from microspheres (1980) Physical Review Letters, 44, pp. 475-478Leung, C.H., She, T.C., Lee, W.K., Positions of low order morphology dependent resonances determined by elastic light scattering (1995) J. Opt. Soc. Am. B, 12, pp. 1259-1266Schaschek, K., Popp, J., Kiefer, W., Observation of morphology dependent in- And output-resonances in time dependent Raman spectra of optically levitated microdroplets (1993) J. Raman Spectrosc., 24, pp. 69-75Ashkin, A., Dziedzic, J.M., Observation of resonances in radiation pressure on dieletric particles (1977) Phys. Rev. Lett., 38, pp. 1351-1354Bisht, P.B., Fukuda, K., Hirayama, S., Steady-state and time-resolved fluorescence study of some dyes in polymer microspheres showing morphology dependent resonances (1996) J. Chem. Phys., 105, pp. 9349-9361Arnold, S., Shift of whispering gallery modes in microspheres by protein adsorption (2003) Opt. Lett., 28, pp. 272-274Vollmer, F., Multiplexed DNA quantification by spectroscopic shift of two microsphere cavities (2003) Biophys. J., 85, pp. 1974-1979Ren, K.F., Gréhan, G., Gouesbet, G., Radiation pressure forces exerted on a particle arbitrarily located in a gaussian beam by using the generalized Lorenz-Mie theory and associated resonance effects (1994) Opt. Commun., 108, pp. 343-354Ren, K.F., Gréhan, G., Gouesbet, G., Symmetry relations in generalized Lorenz-Mie theory (1994) J. Opt. Soc. Am. A, 11, pp. 1812-1817Bohren, C.F., Huffman, D.R., (1983) Absorption and Scattering of Light by Small Particles, , Wiley, New YorkVan De Hulst, H.C., (1981) Light Scattering by Small Particles, , Dover, New YorkDavis, L.W., Theory of electromagnetic beams (1979) Phys. Rev. A, 19, pp. 1177-1779Richards, B., Wolf, E., Electromagnetic diffraction in optical systems II. Structure of the image field in an aplanatic system (1959) Proc. R. Soc. London A, 253, pp. 358-379Ren, K.F., Gouesbet, G., Gréhan, G., Integral localized approximation in generalized Lorenz-Mie theory (1998) Appl. Opt., 37, pp. 4218-4225Lock, J.A., Excitation efficiency of a morphology-dependent resonance by a focused Gaussian beam (1998) J. Opt. Soc. Am. A, 15, pp. 2986-2994Bateman, J.B., Weneck, E.J., Eshler, D.C., Determination of Particle Size and Concentration from Spectrophotometric Transmission (1959) J. Colloid Sci., 14, pp. 308-32

Intensification of heterogeneous photocatalysis by applying a kenics® static mixer as catalyst support

Despite scientific community’s efforts, overcoming mass and photon transfer limitations remain a main challenge for heterogeneous photocatalysis with immobilized catalysts. Here, a Kenics® static mixer was used for the first time as catalyst support for heterogeneous photocatalysis in tubular reactors. This permitted not only to take advantage of the enhanced mass transfer supplied by the intense mixing, but also to provide a total illumination of the photocatalyst surface area with front-irradiation mechanism by using sunlight combined with compound parabolic collectors. Stainless steel Kenics® static mixers were coated with TiO2 or Fe2O3 photocatalyst and applied for oxytetracycline (OTC) degradation in aqueous solutions. The photocatalytic efficiency was evaluated as a function of different parameters: (i) catalyst deposition technique (dip coating or spray coating), (ii) photocatalyst film thickness, (iii) oxidant (H2O2) concentration, and (iv) number of static mixing elements.info:eu-repo/semantics/publishedVersio