Engineering bio-based polymers using alternative solvents and processes

The work presented in this thesis explores novel routes for the processing of bio-based polymers, developing a sustainable approach based on the use of alternative solvents such as supercritical carbon dioxide (scCO2), ionic liquids (ILs) and deep eutectic solvents (DES). The feasibility to produce polymeric foams via supercritical fluid (SCF) foaming, combined with these solvents was assessed, in order to replace conventional foaming techniques that use toxic and harmful solvents. A polymer processing methodology is presented, based on SCF foaming and using scCO2 as a foaming agent. The SCF foaming of different starch based polymeric blends was performed, namely starch/poly(lactic acid) (SPLA) and starch/poly(ε-caprolactone) (SPCL). The foaming process is based on the fact that CO2 molecules can dissolve in the polymer, changing their mechanical properties and after suitable depressurization, are able to create a foamed (porous) material. In these polymer blends, CO2 presents limited solubility and in order to enhance the foaming effect, two different imidazolium based ILs (IBILs) were combined with this process, by doping the blends with IL. The use of ILs proved useful and improved the foaming effect in these starch-based polymer blends. Infrared spectroscopy (FTIR-ATR) proved the existence of interactions between the polymer blend SPLA and ILs, which in turn diminish the forces that hold the polymeric structure. This is directly related with the ability of ILs to dissolve more CO2. This is also clear from the sorption experiments results, where the obtained apparent sorption coefficients in presence of IL are higher compared to the ones of the blend SPLA without IL. The doping of SPCL with ILs was also performed. The foaming of the blend was achieved and resulted in porous materials with conductivity values close to the ones of pure ILs. This can open doors to applications as self-supported conductive materials. A different type of solvents were also used in the previously presented processing method. If different applications of the bio-based polymers are envisaged, replacing ILs must be considered, especially due to the poor sustainability of some ILs and the fact that there is not a well-established toxicity profile. In this work natural DES – NADES – were the solvents of choice. They present some advantages relatively to ILs since they are easy to produce, cheaper, biodegradable and often biocompatible, mainly due to the fact that they are composed of primary metabolites such as sugars, carboxylic acids and amino-acids. NADES were prepared and their physicochemical properties were assessed, namely the thermal behavior, conductivity, density, viscosity and polarity. With this study, it became clear that these properties can vary with the composition of NADES, as well as with their initial water content. The use of NADES in the SCF foaming of SPCL, acting as foaming agent, was also performed and proved successful. The SPCL structure obtained after SCF foaming presented enhanced characteristics (such as porosity) when compared with the ones obtained using ILs as foaming enhancers. DES constituted by therapeutic compounds (THEDES) were also prepared. The combination of choline chloride-mandelic acid, and menthol-ibuprofen, resulted in THEDES with thermal behavior very distinct from the one of their components. The foaming of SPCL with THEDES was successful, and the impregnation of THEDES in SPCL matrices via SCF foaming was successful, and a controlled release system was obtained in the case of menthol-ibuprofen THEDES.

Typology based method for choosing old masonry walls inspection procedures

The diagnosis of historic masonry walls is an intricate and complex field and has been an object of research for many years. This paper aims to propose practical methodologies for the diagnosis of historic masonry walls, specifically based on their typological characteristics. In order to develop such procedures, information relating to historic masonry typologies in Portugal, classified as rural, urban and military was gathered and techniques for the assessment of historic masonry were studied. All information was integrated to develop a pattern typology oriented methodology. Developed methodology was tested and validated in a small diagnosis campaign carried out in the Guimarães Castle. Methodology was proven to be advantageous and although the study is limited and focused on the Portuguese architectural specificities, it still holds global classifications, and therefore can be useful for any diagnosis procedure of a historic masonry wall.

Innovative methodologies for the enhancement of the flexural strengthening performance of NSM CFRP technique for RC beams

Tese de Doutoramento em Engenharia Civil

O desafio da sustentabilidade e da solidariedade na prática dos profissionais de turismo. O turismo de voluntariado no Brasil

Tese de Doutoramento em Geografia - Geografia Humana

Assessing the production of jet mix columns using alkali activated waste based on mechanical and financial performance and CO2 (eq) emissions

Recent research has proved the potential of alkaline activated fly-ash for soil stabilisation. However, such studies have not focused on the link between financial, mechanical and environmental aspects of this solution, but only on their absolute mechanical properties. The present paper characterises the mechanical behaviour of a large spectrum of activator-ash-soil combinations used to build jet mixing columns, analysing also the cost and CO2 (eq) emissions. The concern with these two vectors forced a decrease in the quantity of stabilising agent added to the soil, relatively to previous research, and the effects of such low quantities have not yet been published. However, the results clearly showed a significant improve in strength, still well above the average values expected when improving the stressstrain behaviour of a weak soil. Uniaxial compressive strength tests were used to assess the effects of the fly-ash percentage, the alkalieash ratio and the water content. The carbon calculator recently developed by the European Federation of Foundation Contractors and the Deep Foundations Institute was used to quantify the CO2 (eq) emissions associated with this technique. The financial cost was estimated based on the experience of a major Portuguese contractor. For comparison purposes, soil cement mixtures were also analysed, using similar conditions and tools used for the soil-ash analysis. Results showed that the cement and ash solutions are very similar in terms of overall performance, with some advantage of the former regarding financial cost, and a significant advantage of the latter regarding the CO2 (eq) emissions. This new grout, although it is in an embryonic stage, it has the potential for broader developments in the field.

Combining analytical methodologies for the identification of Aspergillus section Flavi strains isolated from Brazilian agricultural commodities

The use of chemical analysis of microbial components, including proteins, became an important achievement in the 80’s of the last century to the microbial identification. This led a more objective microbial identification scheme, called chemotaxonomy, and the analytical tools used in the field are mainly 1D/2D gel electrophoresis, spectrophotometry, high-performance liquid chromatography, gas chromatography, and combined gas chromatography-mass spectrometry. The Edman degradation reaction was also applied to peptides sequence giving important insights to the microbial identification. The rapid development of these techniques, in association with knowledge generated by DNA sequencing and phylogeny based on rRNA gene and housekeeping genes sequences, boosted the microbial identification to an unparalleled scale. The recent results of mass spectrometry (MS), like Matrix-Assisted Laser Desorption/Ionisation Time-of-Flight (MALDI-TOF), for rapid and reliable microbial identification showed considerable promise. In addition, the technique is rapid, reliable and inexpensive in terms of labour and consumables when compared with other biological techniques. At present, MALDI-TOF MS adds an additional step for polyphasic identification which is essential when there is a paucity of characters or high DNA homologies for delimiting very close related species. The full impact of this approach is now being appreciated when more diverse species are studied in detail and successfully identified. However, even with the best polyphasic system, identification of some taxa remains time-consuming and determining what represents a species remains subjective. The possibilities opened with new and even more robust mass spectrometers combined with sound and reliable databases allow not only the microbial identification based on the proteome fingerprinting but also include de novo specific proteins sequencing as additional step. These approaches are pushing the boundaries in the microbial identification field.

Analysis and selection of indicators for a sustainability assessment method for school buildings based on SBTool ‐ PT

Nowadays, the sustainability of buildings has an extreme importance. This concept goes towards the European aims of the Program Horizon 2020, which concerns about the reduction of the environmental impacts through such aspects as the energy efficiency and renewable technologies, among others. Sustainability is an extremely broad concept but, in this work, it is intended to include the concept of sustainability in buildings. Within the concept that aims the integration of environmental, social and economic levels towards the preservation of the planet and the integrity of the users, there are, currently, several types of tools of environmental certification that are applicable to the construction industry (LEED, BREEAM, DGNB, SBTool, among others). Within this context, it is highlighted the tool SBTool (Sustainable Building Tool) that is employed in several countries and can be subject to review in institutions of basic education, which are the base for the formation of the critical masses and for the development of a country. The main aim of this research is to select indicators that can be used in a methodology for sustainability assessment (SBTool) of school buildings in Portugal and in Brazil. In order to achieve it, it will also be analyzed other methodologies that already incorporate parameters directly related with the schools environment, such as BREEAM or LEED.

Protein-based nanodevices for therapeutic applications

Tese de Doutoramento em Biologia Molecular e Ambiental (área de especialização em Biologia Celular e Saúde).

A UML-based approach for modeling industrial control applications

The main purpose of the poster is to present how the Unified Modeling Language (UML) can be used for diagnosing and optimizing real industrial production systems. By using a car radios production line as a case study, the poster shows the modeling process that can be followed during the analysis phase of complex control applications. In order to guarantee the continuity mapping of the models, the authors propose some guidelines to transform the use cases diagrams into a single object diagram, which is the main diagram for the next phases of the development.

When is the Best Time for the Second Antiplatelet Agent in Non-St Elevation Acute Coronary Syndrome?

Abstract Dual antiplatelet therapy is a well-established treatment in patients with non-ST elevation acute coronary syndrome (NSTE-ACS), with class I of recommendation (level of evidence A) in current national and international guidelines. Nonetheless, these guidelines are not precise or consensual regarding the best time to start the second antiplatelet agent. The evidences are conflicting, and after more than a decade using clopidogrel in this scenario, benefits from the routine pretreatment, i.e. without knowing the coronary anatomy, with dual antiplatelet therapy remain uncertain. The recommendation for the upfront treatment with clopidogrel in NSTE-ACS is based on the reduction of non-fatal events in studies that used the conservative strategy with eventual invasive stratification, after many days of the acute event. This approach is different from the current management of these patients, considering the established benefits from the early invasive strategy, especially in moderate to high-risk patients. The only randomized study to date that specifically tested the pretreatment in NSTE-ACS in the context of early invasive strategy, used prasugrel, and it did not show any benefit in reducing ischemic events with pretreatment. On the contrary, its administration increased the risk of bleeding events. This study has brought the pretreatment again into discussion, and led to changes in recent guidelines of the American and European cardiology societies. In this paper, the authors review the main evidence of the pretreatment with dual antiplatelet therapy in NSTE-ACS.

The principal-agent matching market

We propose a model based on competitive markets in order to analyze an economy with several principals and agents. We model the principal-agent economy as a two-sided matching game and characterize the set of stable outcomes of this principal-agent matching market. A simple mechanism to implement the set of stable outcomes is proposed. Finally, we put forward examples of principal-agent economies where the results fit into.

A Modulated Closed Form solution for Quantitative Susceptibility Mapping - A thorough evaluation and comparison to iterative methods based on edge prior knowledge.

The aim of this study is to perform a thorough comparison of quantitative susceptibility mapping (QSM) techniques and their dependence on the assumptions made. The compared methodologies were: two iterative single orientation methodologies minimizing the l2, l1TV norm of the prior knowledge of the edges of the object, one over-determined multiple orientation method (COSMOS) and anewly proposed modulated closed-form solution (MCF). The performance of these methods was compared using a numerical phantom and in-vivo high resolution (0.65mm isotropic) brain data acquired at 7T using a new coil combination method. For all QSM methods, the relevant regularization and prior-knowledge parameters were systematically changed in order to evaluate the optimal reconstruction in the presence and absence of a ground truth. Additionally, the QSM contrast was compared to conventional gradient recalled echo (GRE) magnitude and R2* maps obtained from the same dataset. The QSM reconstruction results of the single orientation methods show comparable performance. The MCF method has the highest correlation (corrMCF=0.95, r(2)MCF =0.97) with the state of the art method (COSMOS) with additional advantage of extreme fast computation time. The l-curve method gave the visually most satisfactory balance between reduction of streaking artifacts and over-regularization with the latter being overemphasized when the using the COSMOS susceptibility maps as ground-truth. R2* and susceptibility maps, when calculated from the same datasets, although based on distinct features of the data, have a comparable ability to distinguish deep gray matter structures.

Etiology of community-acquired pneumonia in hospitalized children based on WHO clinical guidelines

Rapport de synthèse: Enjeux de la recherche : La pneumonie communautaire chez l'enfant est un problème de santé publique considérable. Elle est responsable de 2 millions de mort par année, 70% survenant dans les pays en voie de développement. Sous nos latitudes son incidence est de 40/1000 enfants par année, ce qui représente une morbidité importante. Deux difficultés surviennent lorsqu'on cherche à diagnostiquer une pneumonie. La première est de distinguer une pneumonie bactérienne d'une virale, particulièrement chez les petits enfants où les infections virales des voies respiratoires inférieures sont fréquentes. L'OMS a définit la pneumonie selon des critères exclusivement cliniques et une étude effectuée à Lausanne en 2000 a montré que ces critères peuvent être utilisés dans nos contrées. La seconde difficulté est de définir l'agent causal de la pneumonie, ceci pour plusieurs raisons : L'aspiration endotrachéale, seul examen fiable, ne peut être obtenue de routine chez l'enfant vu son caractère invasif, la culture des secrétions nasopharyngées reflète la flore physiologique de la sphère ORL et une bactériémie n'est présente que dans moins de 10% des pneumonies. L'étiologie de la pneumonie reste souvent inconnue, et de ce fait plusieurs enfants reçoivent des antibiotiques pour une infection non bactérienne ce qui contribue au développement de résistances. L'objectif de cette étude était d'effectuer une recherche extensive de l'agent causal de la pneumonie et de déterminer quels facteurs pourraient aider le clinicien à différencier une pneumonie virale de bactérienne, en corrélant l'étiologie avec la sévérité clinique et les marqueurs de l'inflammation. Contexte de la recherche : II s'agissait d'une étude prospective, multicentrique, incluant les enfants âgés de 2 mois à 5 ans hospitalisés pour une pneumonie, selon les critères de l'OMS, dans le service de pédiatrie de Lausanne et Genève entre mars 2003 et Décembre 2005, avant l'implantation de la vaccination antipneumococcique de routine. Chaque enfant, en plus des examens usuels, bénéficiait d'une recherche étiologique extensive : Culture virale et bactérienne, PCR (Mycoplasma Pneumoniae, Chlamydia Pneumoniae, Virus Influenza A et B, RSV A et B, Rhinovirus, Parainfluenza 1-3, enterovirus, human metapneumovirus, coronavirus OC43, E229 ; et NL 63) et détection d'AG viraux dans les sécrétions nasopharyngées ; sérologies virales et bactériennes à l'entrée et 3 semaines après la sortie (AG Influenza A et B, Parainfluenza 1,2 et 3, RSV, Adenovirus, M.Pneumoniae et S.Pneumoniae). Conclusions : Un agent pathogène a été découvert chez 86% des 99 patients retenus confirmant le fait que plus la recherche étiologique est étendue plus le pourcentage d'agent causal trouvé est élevé. Une infection bactérienne a été découverte chez 53% des patients dont 45% avaient une infection à S. Pneumoniae confirmant l'importance d'une vaccination antipneumococcique de routine. La déshydratation et les marqueurs de l'inflammation tels que la C-Reactive Protein et la Procalcitonine étaient significativement plus élevés dans les pneumonies bactériennes. Aucune corrélation n'a été trouvée entre le degré de sévérité de la pneumonie et l'étiologie. L'étude a confirmé la haute prévalence d'infections virales (67%) et de co-infection (33%) dans la pneumonie de l'enfant sans que l'on connaisse le rôle réel du virus dans la pathogenèse de la pneumonie. Perspectives : d'autres études à la suite de celle-ci devraient être effectuées en incluant les patients ambulatoires afin de déterminer, avec un collectif plus large de patient, une éventuelle corrélation entre sévérité clinique et étiologie. Abstract : Community-acquired pneumonia (CAP) is a major cause of death in developing countries and of morbidity in developed countries. The objective of the study was to define the causative agents among children hospitalized for CAP defined by WHO guidelines and to correlate etiology with clinical severity and surrogate markers. Investigations included an extensive etiological workup. A potential causative agent was detected in 86% of the 99 enrolled patients, with evidence of bacterial (53%), viral (67%), and mixed (33%) infections. Streptococcus pneumoniae was accounted for in 46% of CAP. Dehydration was the only clinical sign associated with bacterial pneumonia. CRP and PCT were significantly higher in bacterial infections. Increasing the number of diagnostic tests identifies potential causes of CAP in up to 86% of children, indicating a high prevalence of viruses and frequent co-infections. The high proportion of pneumococcal infections re-emphasizes the importance of pneumococcal immunization.

Circulating microRNAs as long-term biomarkers for the detection of erythropoiesis-stimulating agent abuse.

MicroRNAs (miRNAs) are small, non-protein coding transcripts involved in many cellular and physiological mechanisms. Recently, a new class of miRNA called 'circulating miRNAs' was found in cell-free body fluids such as plasma and urine. Circulating miRNAs have been shown to be very stable, specific, and sensitive biomarkers. In this paper, we investigate whether circulating miRNAs can serve as biomarkers for erythropoiesis-stimulating agent abuse. To this end, we analyzed miRNA levels in plasma by miRNA microarrays and quantitative real-time polymerase chain reaction (PCR). Plasma samples are derived from a clinical study with healthy subjects injected with erythropoiesis-stimulating agent (C.E.R.A.). Based on microarray results, we observed a significant difference in the levels of miRNAs in plasma after C.E.R.A. injection. We demonstrated that a specific miRNA, miR-144, exhibit a high increase that lasts 27 days after C.E.R.A. stimulation. Considering the fact that miR-144 is an essential erythropoiesis agent in different organisms, these findings suggest the possibility of using miR-144 as a sensitive and informative biomarker to detect C.E.R.A. abuse. Copyright © 2011 John Wiley & Sons, Ltd.

Evaluation of DNA Recombinant Methodologies for the Diagnosis of Plasmodium falciparum and their Comparison with the Microscopy Assay

Since 1984, DNA tests based on the highly repeated subtelomeric sequences of Plasmodium falciparum (rep 20) have been frequently used in malaria diagnosis. Rep 20 is very specific for this parasite, and is made of 21 bp units, organized in repeated blocks with direct and inverted orientation. Based in this particular organization, we selected a unique consensus oligonucleotide (pf-21) to drive a PCR reaction coupled to hybridization to non-radioactive labeled probes. The pf-21 unique oligo PCR (pf-21-I) assay produced DNA amplification fingerprints when was applied on purified P. falciparum DNA samples (Brazil and Colombia), as well as in patient's blood samples from a large area of Venezuela. The performance of the Pf-21-I assay was compared against Giemsa stained thick blood smears from samples collected at a malaria endemic area of the Bolívar State, Venezuela, at the field station of Malariología in Tumeremo. Coupled to non-radioactive hybridization the pf-21-I performed better than the traditional microscopic method with a r=1.7:1. In the case of mixed infections the r value of P. falciparum detection increased to 2.5:1. The increased diagnostic sensitivity of the test produced with this homologous oligonucleotide could provide an alternative to the epidemiological diagnosis of P. falciparum being currently used in Venezuela endemic areas, where low parasitemia levels and asymptomatic malaria are frequent. In addition, the DNA fingerprint could be tested in molecular population studies