Insight into the multicopper oxidases stability

Dissertation presented to obtain the PhD degree in Biochemistry

Maybelline New York, how to grow in Portugal?

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Etiologia das infeções respiratórias virais em criançass em idade pré-escolar

RESUMO: Os vírus respiratórios continuam a ocupar um papel relevante na morbilidade e mortalidade infantil, tendo na última década sido alargado o espectro de vírus potencialmente causadores das infeções respiratórias. O diagnóstico destas infeções pode ser efetuado por várias metodologias, sendo as técnicas de biologia molecular consideradas as mais sensíveis para este fim. No âmbito do Projeto Ambiente e Saúde em Creches e Infantários (ENVIRH) foi efetuada uma comparação da prevalência dos principais vírus respiratórios em crianças em idade pré-escolar, com critérios de infeção respiratória, recorrendo a técnicas de biologia molecular, em duas populações: crianças que se encontravam na escola/domicilio e crianças que recorreram a uma urgência hospitalar. O estudo decorreu em dois períodos, de Fevereiro a Maio de 2011 e de Outubro de 2011 a Abril de 2012. Foram efetuadas duas colheitas de zaragatoas, uma nasal e outra orofaríngea. A metodologia utilizada para a identificação viral nas amostras foi a PCR e RT-PCR multiplex em tempo real. Os vírus pesquisados foram: Influenza A e B, Parainfluenza 1-4, Metapneumovirus humano, Vírus Sincicial respiratório (VSR), Rinovírus, Enterovírus, Coronavírus e Bocavirus. Foram realizadas 100 colheitas em crianças com idades compreendidas entre os 5 meses e os 5 anos. Foram obtidas 64 amostras dos infantários/domicílios, das quais 47 foram positivas. Da urgência Hospitalar obtiveram-se 36 amostras, em que 32 foram positivas. O vírus da gripe A (H3) foi o mais frequentemente detetado nas duas populações, mas apenas durante o surto de 2012. O VSR e os adenovírus foram mais frequentes nas crianças que recorreram ao hospital, ao contrário dos enterovirus e dos coronavírus, que não foram detetados nesta população. Os bocavirus nunca foram detetados isoladamente. Este estudo reforça a importância de se utilizarem técnicas de biologia molecular para o diagnóstico etiológico das infeções respiratórias, devido à elevada sensibilidade das mesmas, o que se reflete na elevada percentagem de amostras positivas. O facto de se utilizarem técnicas “multiplex”, que permitem a pesquisa simultânea de vários vírus, facilita a deteção de um maior espectro destes agentes. A elevada prevalência de Influenza A H3N2 deveu-se ao facto de grande parte do estudo ter coincidido com um período de surto por este vírus. O sistema de alerta montado durante o projeto ENVIRH pareceu promissor para uma eventual utilização futura em períodos de atividade gripal.--------------ABSTRACT: In the last decade, as respiratory viruses keep representing a relevant factor in child morbidity and mortality, the spectrum of viruses that may potentially cause respiratory infections has been widened. Within the several methodologies that may be applied in the diagnosis of these types of infections, the ones that use molecular biology are considered to be the most sensitive. The Environment and Health in Daycares and Nurseries Project (ENVIRH) arranged for a study, by means of molecular biology techniques, on the main respiratory viruses' influence in pre-school aged children with respiratory infection symptoms. This study compared children in two different populations: children at school or at home and children that were taken to a hospital emergency service. The study was conducted in two different time periods, one from February to May 2011 and the other from October 2011 to April 2012. During this time, two swab collections were held, one nasal and one oropharyngeal. PCR and RT-PCR multiplex in real time techniques were used for viral identification of the samples, searching for the viruses Influenza A and B, Parainfluenza 1-4, human Metapneumovirus, Respiratory Sincytial Virus (RSV), Rhinovirus, Enterovirus, Coronavirus and Bocavirus. One hundred (100) collections were held in children between the ages of 5 months and 5 years, sixty-four (64) at home/school and thirty-six (36) at the hospital's emergency service. From a total of seventy-nine (79) positive samples, forty-seven (47) were obtained at home/school and thirty-two (32) at the hospital. The virus detected the most in both populations was the Influenza A (H3), but only during the outbreak of 2012. Unlike the enteroviruses and coronaviruses, that were not detected within this population, the RSV and the adenoviruses were most common within the children at the hospital. Bocaviruses were never detected isolated from other viruses. The high percentage of positive samples reinforces the significance of using molecular biology techniques for the etiological diagnosis of respiratory infections. The use of multiplex techniques, that make the simultaneous search for multiple viruses possible, enhances the detection of a larger spectrum of such agents. Most of the study coincided with an outbreak of the Influenza A H3N2 virus, thus explaining the high number of its cases identified. The alert system set up during the ENVIRH project looked promising enough for eventual periods of flu activity in the future.

Improvisation in tightly controlled work environments: The case of medical practice

We present a qualitative analysis of organizational improvisation and provide a preliminary insight into the following question: how is improvisation present in tightly controlled work environments? We conducted in situ observations of, and interviews with, several emergency medical teams and complemented this information with statistical and media data. Using grounded theory, we developed four propositions that were arranged into a model that allowed the identification of two use levels of established routines: (1) the visible side that accommodates contextual requirements, and (2) the improvisational side that provides a response to activity characteristics. This dual process is related to the existence of pressures that operate at the institutional level with practical needs emerging from the operational domain. In contrast with most of the literature, this study reveals that the presence of a broad procedural organizational memory does not restrict improvisation but enables a bureaucratic system to produce flexible improvised performance.

O contrato de Project Finance

Currently, Angola portrays a notorious economic growth and due to recent innovative legislations, it has become the major investment attracting pole, especially in Sub-Saharan Africa, having, thus, an extraordinary potentiality for a rapid and sustainable development, likely to place her in outstanding positions in the world economic ranking. Yet, such economic growth entails demanding levels of intensive investment in infrastructure, what has been reported of the Angolan Government to be unable to respond to, save if recurring to very high index of external debt, poisoning, in this way, the future budgeting of the country. Due to these infrastructure investment shortages, the cost of production remains highly onerous and the cost of life extremely unaffordable. On this account, the current study disserts about the contract of Project Finance; an alternative finance resource given as a viable solution for the private financing of infrastructure, aiming to demonstrate that such contractual figure, likewise the experience of several emerging economies and others, is a contract bid framework to take into account in today’s world. It refers to a financing technique – through which the Government may satisfy a common need (for example, the construction of a public domain or public servicing), without having to pay neither offer any collateral – based on a complex legal-financial engineering, arranged throughout a coalition of typical and atypical agreements, whereby it is mandatory to look back at the basic concepts of corporate law. More than just a simple financial study, the dissertation at stake analyses the nature and legal framework of Project Finance, which is a legally atypical and innominate contract, concluding that there is a relevant need for regulating and devoting a special legal regime in the Angolan jurisdiction for this promising legal form in the contemporary corporate finance world.

Experimental and modeling studies on reverse electrodialysis for sustainable power generation

A potentially renewable and sustainable source of energy is the chemical energy associated with solvation of salts. Mixing of two aqueous streams with different saline concentrations is spontaneous and releases energy. The global theoretically obtainable power from salinity gradient energy due to World’s rivers discharge into the oceans has been estimated to be within the range of 1.4-2.6 TW. Reverse electrodialysis (RED) is one of the emerging, membrane-based, technologies for harvesting the salinity gradient energy. A common RED stack is composed by alternately-arranged cation- and anion-exchange membranes, stacked between two electrodes. The compartments between the membranes are alternately fed with concentrated (e.g., sea water) and dilute (e.g., river water) saline solutions. Migration of the respective counter-ions through the membranes leads to ionic current between the electrodes, where an appropriate redox pair converts the chemical salinity gradient energy into electrical energy. Given the importance of the need for new sources of energy for power generation, the present study aims at better understanding and solving current challenges, associated with the RED stack design, fluid dynamics, ionic mass transfer and long-term RED stack performance with natural saline solutions as feedwaters. Chronopotentiometry was used to determinate diffusion boundary layer (DBL) thickness from diffusion relaxation data and the flow entrance effects on mass transfer were found to avail a power generation increase in RED stacks. Increasing the linear flow velocity also leads to a decrease of DBL thickness but on the cost of a higher pressure drop. Pressure drop inside RED stacks was successfully simulated by the developed mathematical model, in which contribution of several pressure drops, that until now have not been considered, was included. The effect of each pressure drop on the RED stack performance was identified and rationalized and guidelines for planning and/or optimization of RED stacks were derived. The design of new profiled membranes, with a chevron corrugation structure, was proposed using computational fluid dynamics (CFD) modeling. The performance of the suggested corrugation geometry was compared with the already existing ones, as well as with the use of conductive and non-conductive spacers. According to the estimations, use of chevron structures grants the highest net power density values, at the best compromise between the mass transfer coefficient and the pressure drop values. Finally, long-term experiments with natural waters were performed, during which fouling was experienced. For the first time, 2D fluorescence spectroscopy was used to monitor RED stack performance, with a dedicated focus on following fouling on ion-exchange membrane surfaces. To extract relevant information from fluorescence spectra, parallel factor analysis (PARAFAC) was performed. Moreover, the information obtained was then used to predict net power density, stack electric resistance and pressure drop by multivariate statistical models based on projection to latent structures (PLS) modeling. The use in such models of 2D fluorescence data, containing hidden, but extractable by PARAFAC, information about fouling on membrane surfaces, considerably improved the models fitting to the experimental data.

COMTEMP: Financing expansion through private equity?

COMTEMP – Companhia de Temperos, Lda. is a Portuguese company that produces vinegars (e.g. CRISTAL vinegars), sauces and condiments. This case study aims to analyze its attractiveness to receive a venture capital investment. The main covered topics are arranged into the following sections: foundation, company, industry, competition, industrial kitchen opportunity, financial strategy and decision.

Phlebotominae sand flies (Diptera: Psychodidae): potential vectors of American cutaneous leishmaniasis agents in the area associated with the Santo Antônio Hydroelectric System in Western Amazonian Brazil

INTRODUCTION: An entomological study was conducted as part of a vector-monitoring program in the area associated with the Santo Antônio hydroelectric system in State of Rondônia, Western Amazonian Brazil. METHODS: Fourteen sampling sites were surveyed to obtain data on the potential vectors of Leishmania spp. in the area. Sand flies were collected from 2011 to 2014 during the months of January/February (rainy season), May/June (dry season), and September/October (intermediary season) using light traps arranged in three vertical strata (0.5, 1, and 20m). RESULTS : A total of 7,575 individuals belonging to 62 species/subspecies were collected. The five most frequently collected sand flies were Psychodopygus davisi (Root) (36.67%), Trichophoromyia ubiquitalis (Mangabeira) (8.51%), Nyssomyia umbratilis (Ward & Fraiha) (6.14%), Bichromomyia flaviscutellata (Mangabeira) (5.74%), and Psychodopygus complexus (Mangabeira) (5.25%). These species have been implicated in the transmission of American cutaneous leishmaniasis agents in the Brazilian Amazon region and described as potential vectors of this disease in the study area. CONCLUSIONS: Additional surveillance is needed, especially in areas where these five species of sand fly are found.

Design and validation of a biomechanical bioreactor for cartilage tissue culture

Specific tissues, such as cartilage undergo mechanical solicitation under their normal performance in human body. In this sense, it seems necessary that proper tissue engineering strategies of these tissues should incorporate mechanical solicitations during cell culture, in order to properly evaluate the influence of the mechanical stimulus. This work reports on a user-friendly bioreactor suitable for applying controlled mechanical stimulation - amplitude and frequency - to three dimensional scaffolds. Its design and main components are described, as well as its operation characteristics. The modular design allows easy cleaning and operating under laminar hood. Different protocols for the sterilization of the hermetic enclosure are tested and ensure lack of observable contaminations, complying with the requirements to be used for cell culture. The cell viability study was performed with KUM5 cells.

Mechanical vs. electrical hysteresis of carbon nanotube/styrene-butadiene-styrene composites and their influence in the electromechanical response

The interesting properties of thermoplastics elastomers can be combined with carbon nanotubes (CNT) for the development of large strain piezoresistive composites for sensor applications. Piezoresistive properties of the composites depend on CNT content, with the gauge factor increasing for concentrations around the percolation threshold, mechanical and electrical hysteresis. The SBS copolymer composition (butadiene/styrene ratio) influences the mechanical and electrical hysteresis of composites and, therefore, the piezoresistive response. This work reports on the electrical and mechanical response of CNT/SBS composites with 4%wt nanofiller content, due to the larger electromechanical response. C401 and C540 SBS copolymers with 80% and 60% butadiene content, respectively have been selected. The copolymer with larger amount of soft phase (C401) shows a rubber-like mechanical behavior, with mechanical hysteresis increasing linearly with strain until 100% strain. The copolymer with the larger amount of hard phase (C540) just shows rubber-like behavior for low strains. The piezoresistive sensibility is similar for both composites for low strains, with a GF≈ 5 for 5% strain. The electrical hysteresis shows opposite behavior than the mechanical hysteresis, increasing with strain for both composites, but with higher increase for softer copolymer, C401. The GF increases with increasing strain, but this increase is larger for composites with lower amounts of soft phase due to the distinct initial modulus and deformation of the soft and hard phases of the copolymer. The soft phase shows larger strain under a given stress than the harder phase and the conductive pathway rearrangements in the composites are different for both phases, the harder copolymer (C540) showing higher piezoresistive sensibility, GF≈ 18, for 20% strain.

Connecting free volume with shape memory properties in noncytotoxic gamma-irradiated polycyclooctene

The free volume holes of a shape memory polymer have been analysed considering that the empty space between molecules is necessary for the molecular motion, and the shape memory response is based on polymer segments acting as molecular switches through variable flexibility with temperature or other stimuli. Therefore, thermomechanical analysis (TMA) and positron annihilation lifetime spectroscopy (PALS) have been applied to analyse shape recovery and free volume hole sizes in gamma irradiated polycyclooctene (PCO) samples, as a non-cytotoxic alternative to more conventional PCO crosslinked via peroxide for future applications in medicine. Thus, a first approach relating structure, free volume holes and shape memory properties in gamma irradiated PCO is presented. The results suggest that free volume holes caused by gamma irradiation in PCO samples facilitate the recovery process by improving movement of polymer chains and open t possibilities for the design and control of the macroscopic response.

Effect of butadiene/styrene ratio, block structure and carbon nanotube content on the mechanical and electrical properties of thermoplastic elastomers after UV ageing

Thermoplastic elastomers based on a triblock copolymer styrene-butadiene-styrene (SBS) with different butadiene/styrene ratios, block structure and carbon nanotube (CNT) content were submitted to accelerated weathering in a Xenontest set up, in order to evaluate their stability to UV ageing. It was concluded that ageing mainly depends on butadiene/styrene ratio and block structure, with radial block structures exhibiting a faster ageing than linear block structures. Moreover, the presence of carbon nanotubes in the SBS copolymer slows down the ageing of the copolymer. The evaluation of the influence of ageing on the mechanical and electrical properties demonstrates that the mechanical degradation is higher for the C401 sample, which is the SBS sample with the largest butadiene content and a radial block structure. On the other hand, a copolymer derivate from SBS, the styrene-ethylene/butadiene-styrene (SEBS) sample, retains a maximum deformation of ~1000% after 80 h of accelerated ageing. The hydrophobicity of the samples decreases with increasing ageing time, the effect being larger for the samples with higher butadiene content. It is also verified that cytotoxicity increases with increasing UV ageing with the exception of SEBS, which remains not cytotoxic up to 80 h of accelerated ageing time, demonstrating its potential for applications involving exposition to environmental conditions.

Influence of oxygen plasma treatment parameters on poly(vinylidene fluoride) electrospun fiber mats wettability

Electrospun poly(vinylidene fluoride) (PVDF) fiber mats find applications in an increasing number of areas, such as battery separators, filtration and detection membranes, due to their excellent properties. However, there are limitations due to the hydrophobic nature and low surface energy of PVDF. In this work, oxygen plasma treatment has been applied in order to modify the surface wettability of PVDF fiber mats and superhydrophilic PVDF electrospun membranes have been obtained. Further, plasma treatment does not significantly influences fiber average size (~400 ± 200 nm), morphology, electroactive -phase content (~80-85%) or the degree of crystallinity (Xc of 42 ± 2%), allowing to maintain the excellent physical-chemical characteristics of PVDF. Plasma treatment mainly induces surface chemistry modifications, such as the introduction of oxygen and release of fluorine atoms that significantly changes polymer membrane wettability by a reduction of the contact angle of the polymer fibers and an overall decrease of the surface tension of the membranes.

Mechanical fatigue performance of PCL-chondroprogenitor constructs after cell culture under bioreactor mechanical stimulus

In tissue engineering of cartilage, polymeric scaffolds are implanted in the damaged tissue and subjected to repeated compression loading cycles. The possibility of failure due to mechanical fatigue has not been properly addressed in these scaffolds. Nevertheless, the macroporous scaffold is susceptible to failure after repeated loading-unloading cycles. This is related to inherent discontinuities in the material due to the micropore structure of the macro-pore walls that act as stress concentration points. In this work, chondrogenic precursor cells have been seeded in Poly-ε-caprolactone (PCL) scaffolds with fibrin and some were submitted to free swelling culture and others to cyclic loading in a bioreactor. After cell culture, all the samples were analyzed for fatigue behavior under repeated loading-unloading cycles. Moreover, some components of the extracellular matrix (ECM) were identified. No differences were observed between samples undergoing free swelling or bioreactor loading conditions, neither respect to matrix components nor to mechanical performance to fatigue. The ECM did not achieve the desired preponderance of collagen type II over collagen type I which is considered the main characteristic of hyaline cartilage ECM. However, prediction in PCL with ECM constructs was possible up to 600 cycles, an enhanced performance when compared to previous works. PCL after cell culture presents an improved fatigue resistance, despite the fact that the measured elastic modulus at the first cycle was similar to PCL with poly(vinyl alcohol) samples. This finding suggests that fatigue analysis in tissue engineering constructs can provide additional information missed with traditional mechanical measurements.

In vitro mechanical fatigue behavior of poly-ε-caprolactone macroporous scaffolds for cartilage tissue engineering: Influence of pore filling by a poly(vinyl alcohol) gel

Polymeric scaffolds used in regenerative therapies are implanted in the damaged tissue and subjected to repeated loading cycles. In the case of articular cartilage engineering, an implanted scaffold is typically subjected to long term dynamic compression. The evolution of the mechanical properties of the scaffold during bioresorption has been deeply studied in the past, but the possibility of failure due to mechanical fatigue has not been properly addressed. Nevertheless, the macroporous scaffold is susceptible to failure after repeated loading-unloading cycles. In this work fatigue studies of polycaprolactone scaffolds were carried by subjecting the scaffold to repeated compression cycles in conditions simulating the scaffold implanted in the articular cartilage. The behaviour of the polycaprolactone sponge with the pores filled with a poly(vinyl alcohol) gel simulating the new formed tissue within the pores was compared with that of the material immersed in water. Results were analyzed with Morrow’s criteria for failure and accurate fittings are obtained just up to 200 loading cycles. It is also shown that the presence of poly(vinyl alcohol) increases the elastic modulus of the scaffolds, the effect being more pronounced with increasing the number of freeze/thawing cycles.