O conceito de cientista em diferentes níveis de ensino

O ensino das ciências experimentais envolve um grande empenho, além de um consumo de tempo elevado, da parte dos professores para promover e induzir uma aprendizagem dinâmica de diversos conceitos científicos. Neste trabalho, é analisado o conceito de cientista no ensino básico e universitário. O presente estudo, relativo ao ano lectivo 2004 / 05, envolveu cerca de 600 alunos do ensino básico, desde o 5.º ao 9.º ano, com idades compreendidas entre os 10 e os 15 anos, das Escolas E.B. 2,3 D. Afonso III, Faro; E.B. 2,3 António Contreiras, Armação de Pêra e E.B. 2,3 Sto. António (n.º 4), Faro. Foram ainda abrangidos neste estudo cerca de 100 alunos do 1.º e 2.º anos das licenciaturas em Bioquímica, Engenharia do Ambiente e Oceanografia da Universidade do Algarve. Aos alunos foram colocadas duas questões, tendo sido definido um tempo máximo de 25 minutos para a primeira e de 15 minutos para a segunda: 1) Faça um desenho de um cientista; e, 2) O que é para ti um cientista

Adaptação de esqueletos metálicos de próteses parciais removíveis produzidos por CAD-CAM – estudo clínico

Objectives: To assess the effect of a CAD-CAM protocol fabrication on the clinical fit accuracy of removable partial denture metal frameworks to abutment teeth. Methods: Fifteen patients with partial edentulism were selected to participate in this clinical study, and twenty dental arch rehabilitations were planned. For each dental arch (n=20), two cobalt-chromium frameworks were produced through two protocols: CAD-CAM production (experimental group); and conventional lost-wax casting technique (control group). Clinical fit accuracy was assessed using an indirect quantitative method to evaluate the gap between the framework occlusal rest and the corresponding rest seat. A silicone mold of that gap was obtained, digitized, and analyzed by micro-computed tomography. The two silicone molds obtained for each occlusal rest were overlapped and evaluated for thickness and volume. Data were analyzed with the paired t test for silicone thickness results and the Wilcoxon test for silicone volume results (α= 0.05). Results: Considering the two dependent variables under study, no statistically significant (p=0.441 for silicone thickness and p=0.204 for silicone volume) differences were found between groups. Conclusions: The results of this study suggest that the CAD-CAM protocol applied is a viable method for the production of removable partial denture metal frameworks.info:eu-repo/semantics/publishedVersio

L-asparaginase recovery through supported ionic liquid materials based on silica

Acute lymphoblastic leukemia (ALL) accounts with approximately 6500 new cases in the United States each year [1]. The first-line biopharmaceutical being used to treat ALL, Oncaspar, is based on L-asparaginase (LA), with annual sales of approximately USD $100 million [2]. The main problem related to the therapeutic use of LA is the difficulty in its purification, accounting for up to 80% of total production costs [3]. Therefore, it is crucial to find new strategies to purify LA in order to decrease its current cost and allow its routinely use by a widespread population. Supported ionic liquid materials based on silica (SILs) are reported in the literature for the separation of natural compounds from vegetable biomass [4]. Although SILs represent a class of materials with high potential in protein purification, this specific application has been scarcely considered [5]. In this work, the search for SILs able to establish (non-covalent) specific interactions with LA, which subsequently allow its purification from the fermentation broth in which it is produced, was studied. In a first set of experiments, commercial LA was used in order to understand the adsorption behaviour of the enzyme onto SILs. Experimental conditions, such as pH, contact time and SILs/LA ratio were evaluated and optimized in what concerns the LA recovery yield. LA activity was assessed by the Nessler reaction, which quantifies the amount of ammonium released after the enzymatic reaction [6]. The results show that the ideal conditions for LA are pH 8 and a contact time with SILs of 30 min. With the envisioned strategy, process costs, energy consumed, and waste generated, can be considerably reduced, which can lead to the LA cost decrease and wider application. Further investigations on the purification of LA from the fermentation broth are ongoing.publishe

Tuberculosis among the homeless: should we change the strategy?

BACKGROUND: Tuberculosis (TB) is a major concern among high-risk populations such as the homeless. OBJECTIVES: To evaluate TB incidence and treatment outcomes among homeless patients in Portugal and to identify predictors of unsuccessful TB treatment outcomes among the homeless. DESIGN: This was a retrospective cohort study of all TB patients notified in Portugal from 2008 to 2014. Characteristics of homeless TB patients were assessed and predictors of unsuccessful TB treatment were determined using logistic regression. RESULTS: TB incidence among the homeless was 122/100 000 homeless persons and was positively correlated with TB incidence among non-homeless persons. Homeless TB patients had a higher prevalence of alcohol and/or drug use, human immunodeficiency virus (HIV) co-infection, cavitary TB and smear positivity. The rate of unsuccessful treatment outcomes among the homeless was 28.6%, and was significantly associated with increased age, injection drug use (IDU) and HIV co-infection. CONCLUSION: TB incidence among homeless persons was five times that among the non-homeless, and higher in regions with greater TB incidence among non homeless persons. The successful treatment outcome rate was lower. Predictors of unsuccessful treatment were age, IDU and HIV co-infection. Integrated TB programmes targeting homeless and non-homeless patients, with measures targeting specific characteristics, may contribute to TB elimination in Portugal.CONTEXTE : La tuberculose (TB) est un souci majeur dans les populations à haut risque comme les personnes sans domicile fixe. OBJECTIFS : Evaluer le taux d’incidence de la TB et les resultats du traitement parmi des patients sans domicile fixe au Portugal et identifier les facteurs de préediction d’ échec du traitement de la TB parmi ces patients. SCHÉMA : Etude rétrospective de cohorte incluant tous les patients TB notifies au Portugal entre 2008 et 2014. Les caractéristiques des patients sans domicile fixe ont été ́évaluées et les facteurs de prédiction d’ échec du traitement de la TB ont été déterminés par ŕegression logistique. RESULTATS : Le taux d’incidence de la TB parmi les personnes sans domicile fixe a été de 122/100 000, et il a été positivement corrélé avec l’incidence de la TB parmi le reste de la population. Les patients tuberculeux sans domicile fixe avaient une prévalence plus élevée de consommation d’alcool et/ou de drogues, de co- infection au virus de l’immunodéficience humaine (VIH), de forme caverneuse et de frottis positif. Le taux d’ ́echec du traitement a ́et ́e de 28,6% ; l’ ́echec a ́ et ́esignificativement associé à un âge plus avancé, à la consommation de drogues injectables et à la co-infection par le VIH. CONCLUSION : L’incidence dela TB parmi les personnes sans domicile fixe a été cinq fois plus élevée que celle du reste de la population et plus haute dans les régions ou l’incidence dans le reste de la population est egalement plus élevée. Leur taux d’ échec du traitement à été plus faible. Les facteurs de prédiction d’ échec du traitement ont été l´âge, la consommation de drogues injectables et la co-infection `a VIH. Des programmes de TB intégrés ciblant les patients sans domicile fixe et les autres, avec des mesures spécifiques adaptées à leurs caractéristiques particulières, pourrait contribuer à l’ élimination de la TB au Portugal.MARCO DE REFERENCIA: La tuberculosis (TB) constituye una gran preocupación en las poblaciones muy vulnerables como las personas sin hogar. OBJETIVOS: Evaluar la tasa de incidencia de TB y los desenlaces terapéuticos en las personas sin domicilio en Portugal y definir los factores pronósticos de fracaso terapéutico en este grupo de la población. MÉTODO: Fue este un estudio retrospectivo de cohortes de todos los pacientes con diagnóstico de TB notificados del 2008 al 2014 en Portugal. Mediante un análisis de regresión logística se analizaron las características de los pacientes tuberculosos sin hogar y los factores pronósticos de fracaso terapéutico. RESULTADOS: La tasa de incidencia de TB en la población sin hogar fue 122 por 100 000 personas y exhibió una correlación positiva con la incidencia de TB en las personas con domicilio. Los pacientes con diagnóstico de TB y sin hogar presentaron una prevalencia más alta de consumo de alcohol y/o de drogas, de coinfección por el virus de la inmunodeficiencia humana (VIH), de lesiones cavernosas y de resultados positivos de la baciloscopia. La tasa de fracaso terapéutico en esta población fue 28,6% y se asoción de manera significativa con una mayor edad, el consumo de drogas intravenosas y la coinfección por el VIH. CONCLUSIÓN: La incidencia de TB en las personas sin hogar fue cinco veces mayor que en las personas con domicilio y fue más alta en las regiones con una mayor incidencia de TB en las personas con domicilio. La tasa de éxito terapéutico en las personas sin hogar fue más baja. Los factores pronósticos de fracaso terapéutico fueron la edad, el consumo de drogas intravenosas y la coinfecció non por el VIH. La ejecución de programas integrados de atención de la TB dirigidos a las personas sin hogar y con domicilio, que comporten medidas específicas que aborden sus características particulares, podrıa contribuir a la eliminación de la TB en PortugalStudy Group for Infectious Diseases of Instituto de Saúde Púublica da Universidade do Porto who collaborated on this project: B Miranda, C Carvalho, C Matos, C Carvalho, G Rodrigues, J Goncalves, L Maio and T Rito. This work was supported by contributions from Iceland, Liechtenstein and Norway through the European Economic Area Grants under the Public Health Initiatives Programme (PT 06, grant number 138DT1). RG was also partially supported by Centro de Matemática da Universidade do Porto (UID/MAT/00144/2013), which is funded by Fundação do Ministério de Ciência e Tecnologia(Portugal) with national (MEC) and European structural funds (Fonds europeen de d ́eveloppement economique et regional) under the PT2020 Partnership Agreementinfo:eu-repo/semantics/publishedVersio

Expression, purification and bioactivity of recombinant human bone morphogenetic protein-4,-9,-10,-11 and-14 produced in Escherichia coli for tissue engineering applications

[Excerpt] Bone morphogenetic proteins (BMPs) are cytokines from the TGFb superfamily, with important roles during embryonic development and in inducing bone and cartilage in the adult body. In this contribution, we report the expression of recombinant human BMP-4, BMP-9, BMP-10, BMP-11 (or growth differentiation factor-11, GDF-11) and BMP-14 (GDF-5), using Escherichia coli pET-25b expression system. The BMPs were purified by affinity chromatography and its bioactivity accessed in C2C12 cell line, by screening the expression of osteogenic markers with RT-PCR. [...]Fundação para a Ciência e Tecnologia for PhD grant SFRH/BD/17049/2004 and project ElastM POCI/CTM/ 57177/2004 supported by FEDER and the Fundação para a Ciência e Tecnologia; European STREP Project HIPPOCRATES (NMP3-CT-2003-505758). The work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283).info:eu-repo/semantics/publishedVersio

Detecting antibody-labeled BCG MNPs using a magnetoresistive biosensor and magnetic labeling technique

Tuberculosis is still a major global health concern, causing the estimated death of 1.5 million people per year and being associated with high morbidity. The development of point-of-care diagnostic tools for tuberculosis is mandatory, especially because the fast and accurate detection of the slow-growing Mycobacterium tuberculosis by the conventional diagnostic tests is difficult. The objective of this work was to develop the first steps to achieve a portable method for the diagnosis of tuberculosis, by a sandwich-immunoassay combined with magnetoresistive biochip technology. With the purpose of conjugating 250 nm streptavidin-coated magnetic nanoparticles with anti-M. tuberculosis biotinylated antibodies, Mycobacterium bovis Bacillus Calmette-Guerin was used as a surrogate for M. tuberculosis bacteria. After magnetic capture, target bacteria were brought in contact with the surface of the magnetoresistive biochip previously functionalized with a secondary anti-M. tuberculosis antibody. Magnetically labeled cells were detected by an array of spin-valve sensors, which change their electrical resistance in the presence of the fringe field of the magnetic particles. Optimization studies on the efficiency of the magnetic capture and further recognition of the bacteria by the secondary antibody on the biochip surface were conducted. The results on the magnetoresistive biochip showed a clear difference in the signal between specific and control ( nonspecific) sensors, suggesting the usefulness of this technique as a potential biorecognition tool for the development of a point-of-care diagnostic method for tuberculosis.Acknowledgments: Teresa Barroso thanks FCT for her PhD Grant SFRH/BD/33904/2009.info:eu-repo/semantics/publishedVersio

Expression, purification and osteogenic bioactivity of recombinant human BMP-4, -9, -10, -11 and -14

Bone morphogenetic proteins (BMPs) are cytokines from the TGF-b superfamily, with important roles during embryonic development and in the induction of bone and cartilage tissue differentiation in the adult body. In this contribution, we report the expression of recombinant human BMP-4, BMP-9, BMP-10, BMP-11 (or growth differentiation factor- 11, GDF-11) and BMP-14 (GDF-5), using Escherichia coli pET-25b vector. BMPs were overexpressed, purified by affinity his-tag chromatography and shown to induce the expression of early markers of bone differentiation (e.g. smad-1, smad-5, runx2/cbfa1, dlx5, osterix, osteopontin, bone sialoprotein and alkaline phosphatase) in C2C12 cells and in human adipose stem cells. The described approach is a promising method for producing large amounts of different recombinant BMPs that show potential for novel biomedical applications.The author wishes to acknowledge the Sanger Institute for kindly offering the bacterial clones for cloning of human BMP-9 to -14. This work was supported by Fundacao para a Ciencia e Tecnologia (PhD grant SFRH/BD/17049/2004, project ElastM POCI/CTM/57177/2004 funded by FEDER and the Fundacao para a Ciencia e Tecnologia; and European STREP Project HIPPOCRATES (NMP3-CT-2003-505758). This work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283)

Silk nanoparticles for delivery of human BMP-2 in bone regenerative medicine applications

[Excerpt] A tissue engineering approach combines the use of scaffold biomaterials, stem cells and growth factors. Bone morphogenetic proteins (BMPs) are growth factors that have sparked a great interest in tissue engineering due to their strong ability to promote new bone formation. Herein, we report the use of silk derived nanoparticles as carriers for delivery of human BMP-2. Silks are attractive biomaterials for tissue engineering due to its biocompatibility, slow biodegradability and excellent mechanical properties. Recombinant human BMP-2 was expressed in Escherichia coli and purified by affinity chromatography, showing bioactivity in human adipose stem cells. BMP2-containing silk particles were then prepared by a water-in-oil emulsion method. [...]info:eu-repo/semantics/publishedVersio

Advanced antibacterial wound dressing produced with natural-origin materials

Portuguese Foundation for Science and Technology for the OsteoGraphy (PTDC/EME- MFE/2008) and MaxBone (PTDC/SAU -ENB/115179/2009) project. This work was partly supported by “RL1 - ABMR - NORTE-01-0124- FEDER-000016” cofinanced by North Portugal Regional Operational Programme (ON.2 – O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF) project.

Shielding AZ91D-1%Ca from corrosion through ultrasound melt treatment: a study for stent design

Magnesium-based materials show great potential for producing biodegradable stents, but their high corrosion rates are a roadblock. This study investigates whether ultrasound melt treatment can change the corrosion response of an extruded AZ91D-1.0%Ca (wt.%) in Earle's Balanced Salt Solution by tailoring the intermetallics' morphology in the as-extruded state. The results showed that the wires from ultrasound-treated ingots corroded faster than non-treated ones in immersion for up to 6 hours. This trend shifted for longer periods, and ultrasound-treated material showed lower corrosion rates and uniform corrosion, while the non-treated material displayed localized corrosion signs. Tensile testing of the wires demonstrated that immersion in EBSS lowered the tensile strength and elongation at fracture due to material degradation, regardless of the processing route. Nonetheless, this decline was sharper in the non-treated material. These findings suggest that ultrasound melt processing can be a promising method for improving the corrosion resistance of magnesium-based materials, paving the way for their use in manufacturing biodegradable stents.This work was supported by Portuguese FCT under the project UIDB/04436/2020, the doctoral grant PD/BD/140094/2018 and SFRH/BD/145285/2019