Reorganização do stiffness em indivíduos com Acidente Vascular Encefálico face à intervenção em fisioterapia. Repercussões no levantar e na marcha

Introdução: A organização estrutural e funcional do sistema nervoso face à organização dos diferentes tipos de input, no âmbito da intervenção em fisioterapia, pode potenciar um controlo postural para a regulação do stiffness e com repercussões na marcha e no levantar. Objetivo: Descrever o comportamento do stiffness da tibiotársica no movimento de dorsiflexão, no membro inferior ispi e contralesional, em indivíduos após Acidente Vascular Encefálico, face a uma intervenção em fisioterapia baseada num processo de raciocínio clínico. Pretendeu-se também observar as modificações ocorridas no âmbito da atividade electromiográfica dos flexores plantares, gastrocnémio medial e solear, durante a marcha e o levantar. Métodos: Foi implementado um programa de reabilitação em 4 indivíduos com sequelas de AVE por um período de 3 meses, tendo sido avaliados no momento inicial e final (M0 e M1). O torque e a amplitude articular da tibiotársica foi monitorizada, através do dinamómetro isocinético, durante o movimento passivo de dorsiflexão, e o nível de atividade eletromiográfica registado, através de electomiografia de superfície, no solear e gastrocnémio medial. Foram estudadas as fases de aceitação de carga no STS (fase II) e na marcha (sub-fase II). Resultados: Em todos os indivíduos em estudo verificou-se que o stiffness apresentou uma modificação no sentido da diminuição em todas as amplitudes em M1. O nível de atividade eletromiográfica teve comportamentos diferentes nos vários indivíduos. Conclusão: O stiffness apontou para uma diminuição nos indivíduos em estudo entre M0 e M1. Foram registadas modificações no nível de atividade eletromiográfica sem que seja possível identificar uma tendência clara entre os dois momentos para esta variável.

Effects of prescribed fire on surface soil in a Pinus pinaster plantation, northern Portugal

In order to decrease the risk of severe wildfire, prescribed fire has recently been adopted in Portugal and elsewhere in the Mediterranean as a major tool for reducing the fuel load instead of manual or mechanical removal of vegetation. There has been some research into its impact on soils in shrublands and grasslands, but to date little research has been conducted in forested areas in the region. As a result, the impact of prescribed fire on the physico-chemical soil characteristics of forest soils has been assumed to be minimal, but this has not been demonstrated. In this study, we present the results of a monitoring campaign of a detailed pre- and post-prescribed fire assessment of soil properties in a long-unburnt P. pinaster plantation, NW Portugal. The soil characteristics examined were pH, total porosity, bulk density, moisture content, organic matter content and litter/ash quantity. The results show that there was no significant impact on the measured soil properties, the only effect being confined to minor changes in the upper 1 cm of soil. We conclude that provided the fire is carried out according to strict guidelines in P. pinaster forest, a minimal impact on soil properties can be expected.

MIP-graphene-modified glassy carbon electrode for the determination of trimethoprim

A novel sensitive electrochemical sensor was developed by electropolymerization of pyrrole(PY)and molecularly imprinted polymer (MIP)which was synthesized onto a glassy carbon electrode (GCE) in aqueous solution using cyclic voltammetry in the presence of Trimethoprim (TMP) as template molecules. Furthermore,a previous electrode modification was performed by deposition of a suspension of graphene on the electrode's surface. The performance of the imprinted and non-imprinted (NIP) films was evaluated by impedance spectroscopy (EIS) and cyclic voltammetry (CV) of a ferric solution. The molecularly imprinted film exhibited a high selectivity and sensitivity toward TMP. The sensor presented a linear range, between peak current intensity and logarithm of TMP concentration between 1.0x10-6 and 1.0x10-4 M. The results were accurate (with recoveries higher than 94%), precise (with standard deviations less than 5%) and the detection limit was 1.3x10-7 M. The new sensor is selective, simple to construct and easy to operate. The MIP sensor was successfully applied to quantify TMP in urinesamples.

An uncertainty and sensitivity analysis applied to the prioritisation of pharmaceuticals as surface water contaminants from wastewater treatment plant direct emissions

In this study, the concentration probability distributions of 82 pharmaceutical compounds detected in the effluents of 179 European wastewater treatment plants were computed and inserted into a multimedia fate model. The comparative ecotoxicological impact of the direct emission of these compounds from wastewater treatment plants on freshwater ecosystems, based on a potentially affected fraction (PAF) of species approach, was assessed to rank compounds based on priority. As many pharmaceuticals are acids or bases, the multimedia fate model accounts for regressions to estimate pH-dependent fate parameters. An uncertainty analysis was performed by means of Monte Carlo analysis, which included the uncertainty of fate and ecotoxicity model input variables, as well as the spatial variability of landscape characteristics on the European continental scale. Several pharmaceutical compounds were identified as being of greatest concern, including 7 analgesics/anti-inflammatories, 3 β-blockers, 3 psychiatric drugs, and 1 each of 6 other therapeutic classes. The fate and impact modelling relied extensively on estimated data, given that most of these compounds have little or no experimental fate or ecotoxicity data available, as well as a limited reported occurrence in effluents. The contribution of estimated model input variables to the variance of freshwater ecotoxicity impact, as well as the lack of experimental abiotic degradation data for most compounds, helped in establishing priorities for further testing. Generally, the effluent concentration and the ecotoxicity effect factor were the model input variables with the most significant effect on the uncertainty of output results.

Modification of cell volume and proliferative capacity of Pseudokirchneriella subcapitata cells exposed to metal stress

The impact of metals (Cd, Cr, Cu and Zn) on growth, cell volume and cell division of the freshwateralga Pseudokirchneriella subcapitata exposed over a period of 72 h was investigated. The algal cells wereexposed to three nominal concentrations of each metal: low (closed to 72 h-EC10values), intermediate(closed to 72 h-EC50values) and high (upper than 72 h-EC90values). The exposure to low metal concen-trations resulted in a decrease of cell volume. On the contrary, for the highest metal concentrations anincrease of cell volume was observed; this effect was particularly notorious for Cd and less pronouncedfor Zn. Two behaviours were found when algal cells were exposed to intermediate concentrations ofmetals: Cu(II) and Cr(VI) induced a reduction of cell volume, while Cd(II) and Zn(II) provoked an oppositeeffect. The simultaneous nucleus staining and cell image analysis, allowed distinguishing three phases inP. subcapitata cell cycle: growth of mother cell; cell division, which includes two divisions of the nucleus;and, release of four autospores. The exposure of P. subcapitata cells to the highest metal concentrationsresulted in the arrest of cell growth before the first nucleus division [for Cr(VI) and Cu(II)] or after thesecond nucleus division but before the cytokinesis (release of autospores) when exposed to Cd(II). Thedifferent impact of metals on algal cell volume and cell-cycle progression, suggests that different toxic-ity mechanisms underlie the action of different metals studied. The simultaneous nucleus staining andcell image analysis, used in the present work, can be a useful tool in the analysis of the toxicity of thepollutants, in P. subcapitata, and help in the elucidation of their different modes of action.

Influência do alinhamento do pé nos Ajustes Posturais Antecipatórios em crianças com Paralisia Cerebral

Introdução: A dificuldade na organização dos ajustes posturais antecipatórios (APAs) é frequentemente associada ao défice de controlo postural (CP) em crianças/jovens com um quadro motor de hemiplegia espástica, resultante de paralisia cerebral. As alterações biomecânicas da tibiotársica e do pé são características comummente observadas nestas crianças/jovens e influenciam o CP na sua globalidade. Objectivo(s): descrever o comportamento dos APAs associados ao início da marcha, face à modificação do alinhamento do pé em crianças/jovens com hemiplegia espástica, após 12 semanas de intervenção, segundo o Conceito Bobath-TND e aplicação de uma Ligadura Funcional (LF). Métodos: Foram avaliadas quatro crianças/jovens num momento inicial (M0) e após 12 semanas de intervenção e de aplicação de uma LF (M1). Recorrendo à eletromiografia de superfície, registaram-se os timings de activação dos músculos tibial anterior, solear, recto abdominal e erector da espinha (bilateralmente). O início do movimento foi calculado a partir da alteração do sinal obtido através da plataforma de pressões. Recorreu-se à aplicação da TMFM-88 para avaliar a função motora global e à aplicação da CIF-CJ para classificar a funcionalidade mediante as actividades e a participação. Procedeu-se ao registo de imagem para facilitar a observação/avaliação das componentes de movimento das crianças/jovens em estudo. Resultados: Após o período de intervenção, verificou-se uma modificação nos valores dos timings de ativação dos músculos em análise, que se aproximaram da janela temporal definida como APAs, bem como na distribuição de carga na base de suporte, nos scores da TMFM-88 e nos qualificadores das “Actividades e Participação”, sugestivos de uma melhor organização dos mecanismos de controlo postural. Conclusão: As crianças/jovens em estudo evidenciaram, após uma intervenção de fisioterapia baseada no Conceito Bobath- TND e aplicação de uma LF, uma evolução favorável tanto ao nível do CP da tibiotársica e do pé, apresentando timings de ativação muscular temporalmente mais ajustados à tarefa, com repercussões positivas nas actividades e participação.

Autonomous bathymetry for risk assessment with ROAZ robotic surface vehicle

The use of unmanned marine robotic vehicles in bathymetric surveys is discussed. This paper presents recent results in autonomous bathymetric missions with the ROAZ autonomous surface vehicle. In particular, robotic surface vehicles such as ROAZ provide an efficient tool in risk assessment for shallow water environments and water land interface zones as the near surf zone in marine coast. ROAZ is an ocean capable catamaran for distinct oceanographic missions, and with the goal to fill the gap were other hydrographic surveys vehicles/systems are not compiled to operate, like very shallow water rivers and marine coastline surf zones. Therefore, the use of robotic systems for risk assessment is validated through several missions performed either in river scenario (in a very shallow water conditions) and in marine coastlines.

Sarcosine oxidase composite screen-printed electrode for sarcosine determination in biological samples

As the prostate cancer (PCa) progresses, sarcosine levels increase both in tumor cells and urine samples, suggesting that this metabolite measurements can help in the creation of non-invasive diagnostic methods for this disease. In this work, a biosensor device was developed for the quantification of sarcosine via electrochemical detection of H2O2 (at 0.6 V) generated from the catalyzed oxidation of sarcosine. The detection was carried out after the modification of carbon screen printed electrodes (SPEs) by immobilization of sarcosine oxidase (SOX) on the electrode surface. The strategies used herein included the activation of the carbon films by an electrochemical step and the formation of an NHS/EDAC layer to bond the enzyme to the electrode, the use of metallic or semiconductor nanoparticles layer previously or during the enzyme immobilization. In order to improve the sensor stability and selectivity a polymeric layer with extra enzyme content was further added. The proposed methodology for the detection of sarcosine allowed obtaining a limit of detection (LOD) of 16 nM, using a linear concentration range between 10 and 100 nM. The biosensor was successfully applied to the analysis of sarcosine in urine samples.

RuSe Electrocatalysts and Single Wall Carbon Nanohorns Supports for the Oxygen Reduction Reaction

Selenium modified ruthenium electrocatalysts supported on carbon black were synthesized using NaBH4 reduction of the metal precursor. Prepared Ru/C electrocatalysts showed high dispersion and very small averaged particle size. These Ru/C electrocatalysts were subsequently modified with Se following two procedures: (a) preformed Ru/carbon catalyst was mixed with SeO2 in xylene and reduced in H2 and (b) Ru metal precursor was mixed with SeO2 followed by reduction with NaBH4. The XRD patterns indicate that a pyrite-type structure was obtained at higher annealing temperatures, regardless of the Ru:Se molar ratio used in the preparation step. A pyrite-type structure also emerged in samples that were not calcined; however, in this case, the pyrite-type structure was only prominent for samples with higher Ru:Se ratios. The characterization of the RuSe/C electrocatalysts suggested that the Se in noncalcined samples was present mainly as an amorphous skin. Preliminary study of activity toward oxygen reduction reaction (ORR) using electrocatalysts with a Ru:Se ratio of 1:0.7 indicated that annealing after modification with Se had a detrimental effect on their activity. This result could be related to the increased particle size of crystalline RuSe2 in heat-treated samples. Higher activity of not annealed RuSe/C catalysts could also be a result of the structure containing amorphous Se skin on the Ru crystal. The electrode obtained using not calcined RuSe showed a very promising performance with a slightly lower activity and higher overpotential in comparison with a commercial Pt/C electrode. Single wall carbon nanohorns (SWNH) were considered for application as ORR electrocatalysts' supports. The characterization of SWNH was carried out regarding their tolerance toward strong catalyzed corrosion conditions. Tests indicated that SWNH have a three times higher electrochemical surface area (ESA) loss than carbon black or Pt commercial electrodes.

Haemoglobin smart plastic antibody material tailored with charged binding sites on silica nanoparticles: its application as an ionophore in potentiometric transduction

This work uses surface imprinting to design a novel smart plastic antibodymaterial (SPAM) for Haemoglobin (Hb). Charged binding sites are described here for the first time to tailor plastic antibody nanostructures for a large size protein such as Hb. Its application to design small, portable and low cost potentiometric devices is presented. The SPAM material was obtained by linking Hb to silica nanoparticles and allowing its ionic interaction with charged vinyl monomers. A neutral polymeric matrix was created around these and the imprinted protein removed. Additional materials were designed in parallel acting as a control: a neutral imprinted material (NSPAM), obtained by removing the charged monomers from the procedure, and the Non-Imprinted (NI) versions of SPAM and NSPAM by removing the template. SEM analysis confirmed the surface modification of the silica nanoparticles. All materials were mixed with PVC/plasticizer and applied as selective membranes in potentiometric transduction. Electromotive force (emf) variations were detected only for selective membranes having a lipophilic anionic additive in the membrane. The presence of Hb inside these membranes was evident and confirmed by FTIR, optical microscopy and Raman spectroscopy. The best performance was found for SPAM-based selective membranes with an anionic lipophilic additive, at pH 5. The limits of detection were 43.8 mg mL 1 and linear responses were obtained down to 83.8 mg mL 1, with an average cationic slope of +40 mV per decade. Good selectivity was also observed against other coexisting biomolecules. The analytical application was conducted successfully, showing accurate and precise results.

Sarcosine oxidase composite screen-printed electrode for sarcosine determination in biological samples

XIX Meeting of the Portuguese Electrochemical Society - XVI Iberic Meeting of Electrochemistry

Multifunctional Biosensor Based on Localized Surface Plasmon Resonance for Monitoring Small Molecule–Protein Interaction

We report an optical sensor based on localized surface plasmon resonance (LSPR) to study small-molecule protein interaction combining high sensitivity refractive index sensing for quantitative binding information and subsequent conformation-sensitive plasmon-activated circular dichroism spectroscopy. The interaction of α-amylase and a small-size molecule (PGG, pentagalloyl glucose) was log concentration-dependent from 0.5 to 154 μM. In situ tests were additionally successfully applied to the analysis of real wine samples. These studies demonstrate that LSPR sensors to monitor small molecule–protein interactions in real time and in situ, which is a great advance within technological platforms for drug discovery.

Protein-responsive polymers for point-of-care detection of cardiac biomarker

This work describes a novel use for the polymeric film, poly(o-aminophenol) (PAP) that was made responsive to a specific protein. This was achieved through templated electropolymerization of aminophenol (AP) in the presence of protein. The procedure involved adsorbing protein on the electrode surface and thereafter electroploymerizing the aminophenol. Proteins embedded at the outer surface of the polymeric film were digested by proteinase K and then washed away thereby creating vacant sites. The capacity of the template film to specifically rebind protein was tested with myoglobin (Myo), a cardiac biomarker for ischemia. The films acted as biomimetic artificial antibodies and were produced on a gold (Au) screen printed electrode (SPE), as a step towards disposable sensors to enable point-of-care applications. Raman spectroscopy was used to follow the surface modification of the Au-SPE. The ability of the material to rebind Myo was measured by electrochemical techniques, namely electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV). The devices displayed linear responses to Myo in EIS and SWV assays down to 4.0 and 3.5 μg/mL, respectively, with detection limits of 1.5 and 0.8 μg/mL. Good selectivity was observed in the presence of troponin T (TnT) and creatine kinase (CKMB) in SWV assays, and accurate results were obtained in applications to spiked serum. The sensor described in this work is a potential tool for screening Myo in point-of-care due to the simplicity of fabrication, disposability, short time response, low cost, good sensitivity and selectivity.

Backside-surface imprinting as a new strategy to generate specific plastic antibody materials

A backside protein-surface imprinting process is presented herein as a novel way to generate specific synthetic antibody materials. The template is covalently bonded to a carboxylated-PVC supporting film previously cast on gold, let to interact with charged monomers and surrounded next by another thick polymer. This polymer is then covalently attached to a transducing element and the backside of this structure (supporting film plus template) is removed as a regular “tape”. The new sensing layer is exposed after the full template removal, showing a high density of re-binding positions, as evidenced by SEM. To ensure that the templates have been efficiently removed, this re-binding layer was cleaned further with a proteolytic enzyme and solution washout. The final material was named MAPS, as in the back-side reading of SPAM, because it acts as a back-side imprinting of this recent approach. It was able to generate, for the first time, a specific response to a complex biomolecule from a synthetic material. Non-imprinted materials (NIMs) were also produced as blank and were used as a control of the imprinting process. All chemical modifications were followed by electrochemical techniques. This was done on a supporting film and transducing element of both MAPS and NIM. Only the MAPS-based device responded to oxLDL and the sensing layer was insensitive to other serum proteins, such as myoglobin and haemoglobin. Linear behaviour between log(C, μg mL−1) versus charged tranfer resistance (RCT, Ω) was observed by electrochemical impedance spectroscopy (EIS). Calibrations made in Fetal Calf Serum (FCS) were linear from 2.5 to 12.5 μg mL−1 (RCT = 946.12 × log C + 1590.7) with an R-squared of 0.9966. Overall, these were promising results towards the design of materials acting close to the natural antibodies and applied to practical use of clinical interest.

Label-free human chorionic gonadotropin detection at picogram levels using oriented antibodies bound to graphene screen-printed electrodes

Human chorionic gonadotropin (hCG) is a key diagnostic marker of pregnancy and an important biomarker for cancers in the prostate, ovaries and bladder and therefore of great importance in diagnosis. For this purpose, a new immunosensor of screen-printed electrodes (SPEs) is presented here. The device was fabricated by introducing a polyaniline (PANI) conductive layer, via in situ electropolymerization of aniline, onto a screen-printed graphene support. The PANI-coated graphene acts as the working electrode of a three terminal electrochemical sensor. The working electrode is functionalised with anti-hCG, by means of a simple process that enabled oriented antibody binding to the PANI layer. The antibody was attached to PANI following activation of the –COOH group at the Fc terminal. Functionalisation of the electrode was analysed and optimized using Electrochemical Impedance Spectroscopy (EIS). Chemical modification of the surface was characterised using Fourier transform infrared, and Raman spectroscopy with confocal microscopy. The graphene–SPE–PANI devices displayed linear responses to hCG in EIS assays from 0.001 to 50 ng mL−1 in real urine, with a detection limit of 0.286 pg mL−1. High selectivity was observed with respect to the presence of the constituent components of urine (urea, creatinine, magnesium chloride, calcium chloride, sodium dihydrogen phosphate, ammonium chloride, potassium sulphate and sodium chloride) at their normal levels, with a negligible sensor response to these chemicals. Successful detection of hCG was also achieved in spiked samples of real urine from a pregnant woman. The immunosensor developed is a promising tool for point-of-care detection of hCG, due to its excellent detection capability, simplicity of fabrication, low-cost, high sensitivity and selectivity.