Esclerose lateral amiotrófica: revisão bibliográfica da patofisiologia

A Esclerose Lateral Amiotrófica (ELA) é uma doença do neurónio motor fatal e progressiva, cuja patogenia é ainda desconhecida. O processo patológico decorre de uma degenerescência dos neurónios motores periféricos no tronco encefálico e medula espinhal, que leva a desnervação e consequente atrofia nas fibras musculares correspondentes. Nas regiões onde ocorre adelgaçamento das fibras nervosas há deposição de pigmentos lipídicos e outras substâncias conjuntamente com proliferação de astroglia e microglia. No início do processo patológico, alguns grupos musculares vão sendo afetados, levando a uma fraqueza muscular assimétrica pouco específica. Com o avançar da doença, vai sendo maior o número de músculos envolvidos, acabando por comprometer a musculatura respiratória e levando à morte. O fenómeno que leva à destruição neuronal ainda não foi esclarecido, o que faz com que esta patologia de rápida progressão seja ainda um grande problema no seio da Neurologia. Devido à ausência de uma etiologia específica, fatores de risco exógeno estão a ser cada vez mais explorados como agente causal da doença. A descoberta contínua de mutações em genes de pacientes com ELA faz com que os fatores genéticos adquiram uma maior importância na etiopatogénese da doença, principalmente porque parecem estar diretamente relacionados com os diversos processos que levam à destruição dos neurónios motores. Os mecanismos que levam à destruição são diversos, entre eles o mecanismo de stress oxidativo, excitotoxicidade pelo glutamato, agregação proteica, alteração da função dos astrócitos, alterações neurovasculares, processos inflamatórios e disfunção dos neurofilamentos e microtúbulos. Nenhum destes processos funciona de modo isolado e diversos estudos apontam para um mecanismo em constante interação que culmina no dano e morte neuronais. O conhecimento escasso da fisiopatologia desta doença leva à dificuldade na elaboração de estratégias terapêuticas eficazes para abrandar o curso da doença. No momento apenas o Riluzole mostra resultados, embora com um aumento da sobrevida dos pacientes em apenas alguns meses. Com o decorrer dos estudos, mais aspetos da ELA têm vindo a ser desvendados, abrindo assim novas possibilidades e hipóteses para estudos mais aprofundados.The Amyotrophic Lateral Sclerosis (ALS) is a fatal and progressive motor neuron disease, whose pathogenesis is still unknown. The pathological process stems from a degeneration of the peripheral motor neurons of the brainstem and spinal cord, which leads to denervation and consequent atrophy of the correspondent muscular fibers. In the regions where occurs muscular fibers’ thinning, occurs deposition of lipid pigments and other substances, as so astroglial and microglial proliferation. In the beginning of the pathological process, some muscular groups are affected, leading to an unspecific asymmetrical muscular weakness. As the disease progresses, larger is the number of affected muscles groups, eventually compromising the respiratory muscles and leading to death. The phenomenon inducing neuronal destruction has not been enlightened, that makes this fast progression pathology a huge problem in the Neurology field. Due to the absence of a specific etiology, exogenous risk factors are being increasingly explored as causative agent of the disease. The ongoing discovery of genes mutations in ALS patients increases genetic factors’ importance in the pathogenesis of the disease, mainly because it seems to be directly linked to several processes responsible for motor neuron destruction. The mechanisms leading to degeneration are several, among them there’s the oxidative stress process, glutamate excitotoxicity, protein aggregation dysfunction, astrocyte dysfunction, neurovascular alterations, inflammatory processes as so neurofilament and microtubule dysfunction. None of this processes act isolated or independently and many studies suggests the existence of a complex mechanism in constant interplay, culminating in neuronal damage and death. The scarce knowledge of ALS’ physiopathology difficult the elaboration of efficient therapeutic strategies intended to slow disease progress. At the moment, only Riluzole shows some significant results, although with just a modest lengthening of the patient’s survival in months. In the course of the studies many aspects of ALS had been discovered, clearing the way to new hypothesis and possibilities for deeper studies

Supported Co catalysts prepared as thin films by magnetron sputtering for sodium borohydride and ammonia borane hydrolysis

Supported Co catalysts were prepared for sodium borohydride and ammonia borane hydrolysis by magnetron sputtering for the first time under different conditions. Ni foam was selected as support. Deposition conditions (time, pressure, and power) were varied to improve catalytic activity. A decrease in deposition power from 200 to 50 W, leads to a decrease in crystallite and column size and a higher activity of catalysts. The increase in deposition pressure from 1.5 × 10−2 to 4.5 × 10−2 mbar produces same effect but in this case the enhancement in activity is higher because amorphous materials were obtained. The highest activity for SB hydrolysis was 2650 ml min−1 gcat−1 for the 50 W Co 4.5 (4 h) sample (Ea = 60 ± 2 kJ mol−1). For AB hydrolysis activity for the 50 W Co 3.2 (4 h) sample was similar. Durability of the thin films was tested for both reactions upon cycling (14 cycles). Diluted acid washing was effective to recover the activity for sodium borohydride reaction but not for ammonia borane hydrolysis. The strong Co–NH3 interactions explain the non-efficiency of the acid washing

Utilização de produtos do Copernicus Global Land Service em contexto de incêndios florestais em Portugal

A cobertura vegetal da superfície terrestre sofre alterações constantes devido à natureza das condições atmosféricas e à pressão antropogénica. O Copernicus Global Land Service (CGLS) disponibiliza um conjunto de variáveis biogeofísicas que permitem seguir o estado e evolução da vegetação terrestre. Estas variáveis são essenciais na determinação do estado da superfície em modelos de propagação de incêndios florestais, cuja severidade depende da disponibilidade de biomassa e teor de humidade do solo. No cenário de grandes incêndios florestais que ocorreram em Portugal, foram analisados para a mesma área geográfica antes e após a ocorrência dos incêndios, vários índices disponibilizados pelo CGLS. Particulariza-se o caso do SWI (do inglês Soil Water Index), que não sofreu aparentemente alteração no seu comportamento depois dos incêndios. Com este trabalho pretende-se mostrar a análise efetuada com índices CGLS e investigar qual a razão para o SWI não detetar o sinal dos incêndios. Deste modo, os produtos SSM (do inglês Surface Soil Moisture) obtido a partir do satélite Sentinel-1 (banda C-SAR) e SSM obtido a partir do satélite Metop (sensor ASCAT) nos quais o SWI é baseado serão também analisados e comparados

Improved corrosion behavior and biocompatibility of porous Titanium samples coated with bioactive Chitosan-based nanocomposites

Producción CientíficaPorous titanium implants can be a good solution to solve the stress shielding phenomenon. However, the presence of pores compromises mechanical and corrosion resistance. In this work, porous titanium samples obtained using a space-holder technique are coated with Chitosan, Chitosan/AgNPs and Chitosan/Hydroxyapatite using only one step and an economic electrodeposition method. The coatings’ topography, homogeneity and chemical composition were analyzed. A study of the effect of the porosity and type of coating on corrosion resistance and cellular behavior was carried out. The electrochemical studies reveal that porous samples show high current densities and an unstable oxide film; therefore, there is a need for surface treatments to improve corrosion resistance. The Chitosan coatings provide a significant improvement in the corrosion resistance, but the Chitosan/AgNPs and Chitosan/HA coatings showed the highest protection efficiency, especially for the more porous samples. Furthermore, these coatings have better adherence than the chitosan coatings, and the higher surface roughness obtained favors cell adhesion and proliferation. Finally, a combination of coating and porous substrate material with the best biomechanical balance and biofunctional behavior is proposed as a potential candidate for the replacement of small, damaged bone tissues.Ministerio de Ciencia, Innovación y Universidades (grants RTI2018-097990-B-I00 and PID2019-109371GB-I00)Junta de Andalucía - Fondo Europeo de Desarrollo Regional (project US-1259771)Junta de Castilla y León (projects VA275P18 and VA044G19

Electropolymerized polypyrrole silver nanocomposite coatings on porous Ti substrates with enhanced corrosion and antibacterial behavior for biomedical applications

Producción CientíficaThis work proposes an innovative strategy that combines two well-known easy and economical preparation techniques: powder metallurgy based space-holder (SH) technique to provide porous biocompatible Ti substrates with balanced biomechanical behavior (for cortical bone tissue substitution) promoting bone ingrowth and biocoating infiltration, and electropolymerization to coat these substrates with the polypyrrole–silver nanoparticles (PPy-AgNPs) composite conductive polymers improving its corrosion resistance, biocompatibility with enhanced antibacterial activity. The deposited PPy-based coatings present a cauliflower-like structure well adhered to the porous substrates. The macroporosity of and rough inner pore surface of Ti SH substrates are responsible for the superior adhesion of the conductive polymer comparing to typical denser substrates obtained by powder metallurgy or forging. The corrosion protection properties of the coatings were investigated by open circuit potential and Anodic Polarization in PBS media to simulate possible implant conditions, revealing improved corrosion resistance for the composite coatings. The bioactivity of the coatings was evaluated by immersion tests, revealing the formation of Hydroxyapatite after 90-day immersion in PBS. In both PPy and PPy-AgNPs composite coatings, a displacement of the polarization curves to more noble potentials and a decrease in the current density, indicated that the coating's protective character is maintained after 90-day immersion in PBS. The antibacterial activity was assessed by using the Kirby–Bauer disk-diffusion method against Staphylococcus aureus (ATCC 25923). The inhibition halo increased from 5.5 ± 0.4 mm for the bare substrate to 8.2 ± 0.6 mm for the PPy-coated substrate and to 12.5 ± 0.7 mm for the PPy-AgNPs-coated porous Ti. This feature associated to the improved corrosion protection and biocompatibility would significantly contribute to the success of the potential use of porous Ti implants by SH technique envisaging substitution of small damaged bone tissues for example in tumors.Ministerio de Ciencia e Innovación (RTI2018-097990-B-I00 y PID2019-109371 GB-I00)Junta de Andalucía–FEDER (US-1259771)Junta de Castilla y León (VA275P18 y VA044G19

Nanoscale characterization of Co and Co-B catalytic coatings before and after catalytic tests for the sodium borohydride hydrolysis

Capítulo tomado de https://onlinelibrary.wiley.com/doi/pdf/10.1002/9783527808465.EMC2016.5347Spanish MINECO (CTQ2012-32519 and CTQ2015-65918)CONSOLIDER FUNCOAT+ (MAT2015-69035-REDC)Junta de Andalucía (PE2012-TEP862)CSIC (PIE201460E018)Laboratory for Nanoscopies and Spectroscopies (LANE) at the ICMSTalent-Hub Program funded by the Junta de Andalucía and the European Commission under the Co-funding of the 7thFramework Program in the People Program (Marie Curie Special Action

Characterization and Validation of a‑Si Magnetron-Sputtered Thin Films as Solid He Targets with High Stability for Nuclear Reactions

In this work, we present our magnetron sputtering based methodology to produce amorphous silicon coatings with closed porosity, as a strategy to fabricate solid helium targets, in the form of supported or self-supported thin films, for nuclear reactions. We show how by changing the He working pressure it is possible to obtain highly porous homogeneous structures incorporating different He amounts. These porous coatings (a- Si:He) are very reproducible from run to run, and the high He amount incorporated makes them excellent candidates for solid He targets. The possibility of producing self-supported films is illustrated here, and its potential use in inverse kinematics experiments with radioactive beams is shown through the dispersion in forward geometry of a stable 6Li beam. Also the elastic scattering cross-sections for proton from helium were determined using an a-Si:He coating. The results agree well with the ones reported in the literature. These two examples validate our coatings as good candidates to be used as solid He targets in nuclear reactions. The stability of He inside the coatings, fundamental for its use as solid He targets, was investigated, both over time and after irradiation. The coatings proved to be very stable, and the amount of He inside the pores remains unaltered at least 2 years after deposition and after high irradiation fluence (5 × 1017 particles/cm2; with a dose rate of 5 × 1012 particles/(cm2 s)).Ministerio de Economía y Competitividad FPA2013-47327-C2-1-R, MAT2015-69035- REDCConsejo Superior de Investigaciones Científicas 201460E018European Union CT-REGPOT-2011-28589

Development of porous silver nanoparticle/polycaprolactone/polyvinyl alcohol coatings for prophylaxis in titanium interconnected samples for dental implants

Stress shielding phenomenon, poor osseointegration, or bacterial infections of titanium dental implants are widely recognized as key problems that deeply affect their survival rate. In this work, a joint solution to solve these three limitations is proposed. The first two issues were minimized applying porous Ti samples. This substrate exhibits an appropriated biomechanical equilibrium (stiffness and mechanical resistance) and good biofunctionality (ability to promote bone ingrowth). On the other hand, the porous Ti disc was coated with biocompatible and non-toxic polymeric composites matrices using poly-ε-caprolactone and partially acetylated polyvinyl alcohol, combined with silver nanoparticles as a therapeutic antimicrobial agent. The optimization of the best blend composition and optimal nanoparticles concentration were investigated. Finally, the two composites with the best antimicrobial activity were infiltrated into porous Ti discs. The deposited coatings presented good adhesion and a honeycomb-like surface structure that could promote vascularization of the implant and enhance osseointegration.Ministry of Science and Innovation of Spain grant PID2019-109371GB-I00Junta de Andalucía (Spain) PAIDI P20_00671FEDER Andalucía US-1380878Universidad de Sevilla, Spain PPI505/2020Universidad de Sevilla, Spain PPI532/202

Development of porous silver nanoparticle/polycaprolactone/polyvinyl alcohol coatings for prophylaxis in titanium interconnected samples for dental implants

Stress shielding phenomenon, poor osseointegration, or bacterial infections of titanium dental implants are widely recognized as key problems that deeply affect their survival rate. In this work, a joint solution to solve these three limitations is proposed. The first two issues were minimized applying porous Ti samples. This substrate exhibits an appropriated biomechanical equilibrium (stiffness and mechanical resistance) and good biofunctionality (ability to promote bone ingrowth). On the other hand, the porous Ti disc was coated with biocompatible and non-toxic polymeric composites matrices using poly-ε-caprolactone and partially acetylated polyvinyl alcohol, combined with silver nanoparticles as a therapeutic antimicrobial agent. The optimization of the best blend composition and optimal nanoparticles concentration were investigated. Finally, the two composites with the best antimicrobial activity were infiltrated into porous Ti discs. The deposited coatings presented good adhesion and a honeycomb-like surface structure that could promote vascularization of the implant and enhance osseointegration.Ministerio de Ciencia e Innovación PID2019-109371GB-I00Junta de Andalucía PAIDI 2020, P20_00671Universidad de Sevilla US-138087, PPI505/2020, PPI532/202

Avaliação do Estado Mental para Estimulação Cerebral Profunda: “ON” vs. “OFF”

Paper presented at the Annual Meeting of Portuguese Movement Disorders Society, 13-15 March 2015, Ofir, Portugal.Comunicação apresentada no Congresso Nacional da Sociedade Portuguesa das Doenças do Movimento (SPDMov), 13-15 Março 2015, Ofir, Portugal