Old cellulose for new multifunctional networks

Dissertação para obtenção do Grau de Doutor em Ciência e Engenharia de Materiais

Use of leaves for drinking water

The use of leaves for drinking water is a widespread tool-use behavior among chimpanzees. Although this tool-use behavior is widely described as the use of leaf sponges, it can actually be found in three different forms: leaf sponges, leaf-folding, and leaf spoons. Among the chimpanzee community of Bossou, we can observe all three forms, albeit in different frequencies. Here I describe the longitudinal record of manufacture and use of leaf tools for drinking water, highlighting the learning process underlying the acquisition of the skill. The degree of laterality evident in both immature and mature performers is also presented here. The use of leaves for drinking water emerges at the age of 1.5 years old, but the manufacture of leaf tools only starts at 3.5 years of age. Infants and juveniles were observed to use drinking tools that had been discarded by other individuals after use. Concerning handedness in general, the chimpanzees are ambidextrous, with some individuals biased to one side.

Exit strategies of Pharmaceutical multinational companies from Portugal and the successful implementation of new Portuguese companies

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

Potential for ORC application in the Portuguese manufacturing industry

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente, perfil Gestão e Sistemas Ambientais

O sal na alimentação dos jovens : avaliação e perceção do sal das refeições

RESUMO: Considerando que a pressão arterial elevada constitui um dos maiores fatores de risco para as doenças cardiovasculares, a sua associação ao consumo elevado de sal, e o facto das escolas constituírem ambientes de excelência para a aquisição de bons hábitos alimentes e promoção da saúde, o objetivo deste estudo foi avaliar o conteúdo de sal presente nas refeições escolares e a perceção dos consumidores sobre o sabor salgado. A quantificação de sal foi realizada com um medidor portátil. Para avaliar a perceção dos consumidores foi desenvolvido e aplicado um questionário a alunos das escolas preparatórias e secundárias e aos responsáveis pela preparação e confeção das refeições. Foram analisadas um total de 898 componentes de refeições, incluindo refeições escolares e de restauração padronizada. Em média, as refeições escolares disponibilizam entre 2,83 a 3,82 g de sal por porção servida (p=0,05), o que representa entre duas a cinco vezes mais as necessidades das crianças e jovens. Os componentes das refeições padronizadas apresentam um valor médio de sal que varia entre 0,8 e 2,57 g por porção (p=0,05), o que pode contribuir para um valor total de sal por refeição mais elevado comparativamente com as refeições escolares. O sabor das refeições é percecionado como sendo nem salgado nem insonso para a maioria dos estudantes, o que parece demonstrar habituação à intensidade/ quantidade de sal consumida. Os responsáveis pelas refeições, apesar de apresentarem conhecimentos sobre sal e a necessidade da sua limitação, demonstram barreiras e limitações e perceções à sua redução. A realização de escolhas alimentares saudáveis e adequadas só é possível se suportada por um ambiente facilitador dessas mesmas escolas. O impacto que o consumo de sal tem na saúde, em particular nas doenças crónicas, torna imperativa a implementação de estratégias de redução de sal ao nível da indústria e dos serviços de catering e restauração, em particular direcionadas para o público mais jovem.------------ABSTRACT Considering the fact that high blood pressure is a major rick factor for cardiovascular disease and its association to salt intake and the fact that schools are considered ideal environments to promote health and proper eating habits, the objective of this study was to evaluate the amount of salt in meals served in school canteens and consumers perceptions about salt. Quantification of salt was performed using a portable salt meter - PAL ES2. For food perception we constructed a questionnaire that was applied to students from high schools. A total of 898 food samples were analysed. Bread presents the highest value with a mean of 1.35 (SD=0.12). Salt in soups ranges from 0.72 g/100 g to 0.80 g/100 g (p=0.05) and main courses from 0.71 g/100 to 0.97 g/100g (p=0.05). Salt in school meals is high with a mean value from 2.83 to 3.82 g of salt per meal, which is between 2 and 5 times more than the RDA for children. The components of standardized meals have an average value of salt ranging from 0.8 to 2.57 g per serving, which may contribute to a higher intake of salt per meal compared to school meals. Moreover, a high percentage of students consider meals neither salty nor lacking in salt, which shows they are used to the intensity/amount of salt consumed. Despite the knowledge and perceived necessity about salt reduction, those responsible for cooking and preparing meals, still demonstrate barriers and limitation in doing so. Making healthy choices is only possible if backed up by an environment where such choices are accessible. Therefore salt reduction strategies, aimed at the food industry and catering services should be implemented, with children and young people targeted as a major priority.

Study of salt stress tolerance in spelt

World population is increasing at an alarming rate while food productivity is decreasing due to the effect of various abiotic stresses. Soil salinity is one of the most important abiotic stress and a limiting factor for worldwide plant production. In addition to its important effects on yield, salt stress affects numerous cellular activities, including cell wall composition, photosynthesis, protein synthesis, ions and organic solutes. Up to 20% of the irrigated arable land in arid and semiarid regions is already salt affected and is still expanding. Improving salt tolerant varieties is of major importance, and efforts should be focused on finding adaptive mechanisms which are involved in salinity tolerance. In this study, several spelt wheat (Triticum aestivum var. Spelta) genotypes and one cultivar of modern bread wheat were used to screen them for salt tolerance. Spelt is an old-European cereal crop currently attracting renewed interest as a food grain because it is said to be harder than wheat and requires less fertilizer. Spelt wheat is also becoming very attractive genetic source by plant breeders due to its wide adaptation ability to various stressful conditions such as soil salinity. In this study morphological parameters (e.g., leaf appearance; shoot elongation), dry matter production, mineral nutrients (especially Na and K), and activity of antioxidative enzymes were measured to select superior genotypes of spelt for salt tolerance. The results showed that Spelt genotype Sp41 is a salt sensitive genotype and genotypes Sp69, Sp96 and Sp912 are good candidates for salt tolerant genotypes.

Cost of drugs manufactured by the University Hospital - role of the Central Pharmacy

The hospital pharmacy in large and advanced institutions has evolved from a simple storage and distribution unit into a highly specialized manipulation and dispensation center, responsible for the handling of hundreds of clinical requests, many of them unique and not obtainable from commercial companies. It was therefore quite natural that in many environments, a manufacturing service was gradually established, to cater to both conventional and extraordinary demands of the medical staff. That was the case of Hospital das Clinicas, where multiple categories of drugs are routinely produced inside the pharmacy. However, cost-containment imperatives dictate that such activities be reassessed in the light of their efficiency and essentiality. METHODS: In a prospective study, the output of the Manufacturing Service of the Central Pharmacy during a 12-month period was documented and classified into three types. Group I comprised drugs similar to commercially distributed products, Group II included exclusive formulations for routine consumption, and Group III dealt with special demands related to clinical investigations. RESULTS: Findings for the three categories indicated that these groups represented 34.4%, 45.3%, and 20.3% of total manufacture orders, respectively. Costs of production were assessed and compared with market prices for Group 1 preparations, indicating savings of 63.5%. When applied to the other groups, for which direct equivalent in market value did not exist, these results would suggest total yearly savings of over 5 100 000 US dollars. Even considering that these calculations leave out many components of cost, notably those concerning marketing and distribution, it might still be concluded that at least part of the savings achieved were real. CONCLUSIONS: The observed savings, allied with the convenience and reliability with which the Central Pharmacy performed its obligations, support the contention that internal manufacture of pharmaceutical formulations was a cost-effective alternative in the described setting.

Minimal computation structures for visual information applications based on printed electronics

In the early nineties, Mark Weiser wrote a series of seminal papers that introduced the concept of Ubiquitous Computing. According to Weiser, computers require too much attention from the user, drawing his focus from the tasks at hand. Instead of being the centre of attention, computers should be so natural that they would vanish into the human environment. Computers become not only truly pervasive but also effectively invisible and unobtrusive to the user. This requires not only for smaller, cheaper and low power consumption computers, but also for equally convenient display solutions that can be harmoniously integrated into our surroundings. With the advent of Printed Electronics, new ways to link the physical and the digital worlds became available. By combining common printing techniques such as inkjet printing with electro-optical functional inks, it is starting to be possible not only to mass-produce extremely thin, flexible and cost effective electronic circuits but also to introduce electronic functionalities into products where it was previously unavailable. Indeed, Printed Electronics is enabling the creation of novel sensing and display elements for interactive devices, free of form factor. At the same time, the rise in the availability and affordability of digital fabrication technologies, namely of 3D printers, to the average consumer is fostering a new industrial (digital) revolution and the democratisation of innovation. Nowadays, end-users are already able to custom design and manufacture on demand their own physical products, according to their own needs. In the future, they will be able to fabricate interactive digital devices with user-specific form and functionality from the comfort of their homes. This thesis explores how task-specific, low computation, interactive devices capable of presenting dynamic visual information can be created using Printed Electronics technologies, whilst following an approach based on the ideals behind Personal Fabrication. Focus is given on the use of printed electrochromic displays as a medium for delivering dynamic digital information. According to the architecture of the displays, several approaches are highlighted and categorised. Furthermore, a pictorial computation model based on extended cellular automata principles is used to programme dynamic simulation models into matrix-based electrochromic displays. Envisaged applications include the modelling of physical, chemical, biological, and environmental phenomena.

Guidelines on how to assess the validity of results presented in subgroup analysis of clinical trials

In observational studies, identification of associations within particular subgroups is the usual method of investigation. As an exploratory method, it is the bread and butter of epidemiological research. Nearly everything that has been learned in epidemiology has been derived from the analysis of subgroups. In a randomized clinical trial, the entire purpose is the comparison of the test subjects and the controls, and when there is particular interest in the results of treatment in a certain section of trial participants, a subgroup analysis is performed. These subgroups are examined to see if they are liable to a greater benefit or risk from treatment. Thus, analyzing patient subsets is a natural part of the process of improving therapeutic knowledge through clinical trials. Nevertheless, the reliability of subgroup analysis can often be poor because of problems of multiplicity and limitations in the numbers of patients studied. The naive interpretation of the results of such examinations is a cause of great confusion in the therapeutic literature. We emphasize the need for readers to be aware that inferences based on comparisons between subgroups in randomized clinical trials should be approached more cautiously than those based on the main comparison. That is, subgroup analysis results derived from a sound clinical trial are not necessarily valid; one must not jump to conclusions and accept the validity of subgroup analysis results without an appropriate judgment.

Portuguese footwear

This case study deals with the reasons why the Portuguese Footwear Cluster evolved from a small industry focused on the Portuguese internal market into a high-tech industry capable of designing and producing some of the best and most expensive shoes in the world. It went from using the low labor costs of an under-developed economy to produce long series of shoes for pre-designated brands in Northern Europe to having the ability to produce some of the highest quality shoes in the world, in small orders, designed and delivered in record timing, while offering a service of excellence. In 1960, when Portugal became a founding member of EFTA, the footwear industry in Portugal was globally irrelevant, producing low quality shoes directed to the puny internal market and its African colonies. The new free trade zone with economies much more developed that itself, led to the transfer of the labor-intensive, low skilled manufacture from the UK and Scandinavian countries to Portugal. Mostly through joint ventures, the industry was able to mechanize itself so it could produce shoes in long series at low prices. It grew based on that model up until the 1990s, when the emergence of the Asian countries meant either a different strategy or extinction. Taking advantage of a clarified leadership of its trade association, it used the European funds made available to it during the 1990s, to modernize its factory floors, so it could become more nimble and flexible, expand its design capabilities and dramatically change its image abroad. The role of the trade association, APICCAPS, was instrumental throughout the process going well beyond what came to be expected of trade associations. It used its privileged position to provide understanding regarding the current situation and competitive landscape, alerting for changes ahead and at the same time providing a strategic vision on how to deal with the challenges. Moreover, it helped companies get the resources they needed by creating a research center in collaboration with a University, by creating a process that allowed companies to learn from each other via the show casing of projects sponsored by the association or by helping industrials traveling to locations where new customers could be found. The case study provides insight on how the trade association leadership, which has no formal authority over its members, was able to guide and motivate an industry through a consistent positive approach. That approach focused on the solutions, on the opportunities and on the success stories of companies in the cluster rather than on what was wrong or needed to be addressed. Based on this case, one could use the leadership role of the trade association to discuss and change leaders’ roles and styles in other sectors or even companies.

Organic-inorganic nanostructured multilayers for calcium phosphate biomineralization

The weak fixation of biomaterials within the bone structure is one of the major reasons of implants failures. Calcium phosphate (CaP) coatings are used in bone tissue engineering to improve implant osseointegration by enhancing cellular adhesion, proliferation and differentiation, leading to a tight and stable junction between implant and host bone. It has also been observed that materials compatible with bone tissue either have a CaP coating or develop such a calcified surface upon implantation. Thus, the development of bioactive coatings becomes essential for further improvement of integration with the surrounding tissue. However, most of current applied CaP coatings methods (e.g. physical vapor deposition), cannot be applied to complex shapes and porous implants, provide poor structural control over the coating and prevent incorporation of bioactive organic compounds (e.g. antibiotics, growth factors) because of the used harsh processing conditions. Layer-by-layer (LbL) is a versatile technology that permits the building-up of multilayered polyelectrolyte films in mild conditions based on the alternate adsorption of cationic and anionic elements that can integrate bioactive compounds. As it is recognized in natureâ s biomineralization process the presence of an organic template to induce mineral deposition, this work investigate a ion based biomimetic method where all the process is based on LbL methodology made of weak natural-origin polyelectrolytes. A nanostructured multilayer component, with 5 or 10 bilayers, was produced initially using chitosan and chondroitin sulphate polyelectrolyte biopolymers, which possess similarities with the extracellular matrix and good biocompatibility. The multilayers are then rinsed with a sequential passing of solutions containing Ca2+ and PO43- ions. The formation of CaP over the polyelectrolyte multilayers was confirmed by QCM-D, SEM and EDX. The outcomes show that 10 polyelectrolyte bilayer condition behaved as a  better site for initiating the formation of CaP as the precipitation occur at earlier stages than in 5 polyelectrolyte bilayers one. This denotes that higher number of bilayers could hold the CaP crystals more efficiently. This work achieved uniform coatings that can be applied to any surface with access to the liquid media in a low-temperature method, which potentiates the manufacture of effective bioactive biomaterials with great potential in orthopedic applications.

Saloplastic membranes as green devices for soft tissue regeneration

Implantable devices must exhibit mechanical properties similar to native tissues to promote appropriate cellular behavior and regeneration. Herein, we report a new membrane manufacture method based on the synthesis of polyelectrolyte complexes (PECs) that exhibit saloplasticity, i.e. variable physical-chemistry using salt as a plasticizer. This is a Green Chemistry approach, as PECs generate structures that are stabilized solely by reversible electrostatic interactions, avoiding the use of harmful crosslinkers completely. Furthermore, natural polyelectrolytes - chitosan and alginate - were used. Upon mixing them, membranes were obtained by drying the PECs at 37ºC, yielding compact PECs without resorting to organicsolvents. The plasticizing effect of salt after synthesis was shown by measuring tensile mechanical properties, which were lower when samples were immersed in high ionic strength solutions.Salt was also used during membrane synthesis in different quan- tities (0 M, 0.15 M and 0.5 M in NaCl) yielding structures with no significant differences in morphology and degradation (around 15% after 3 months in lysozyme). However, swelling was higher (about 10x) when synthesized in the presence of salt. In vitro cell studies using L929 fibroblasts showed that cells adhered and proliferated preferentially in membranes fabricated in the presence of salt (i.e. the membranes with lower tensile strength). Structures with physical-chemical properties controlled with precision open a path to tissue engineering strategies depending on fine tuning mechanical properties and cellular adhesion simply by changing ionic strength during membrane manufacture

Controlo da qualidade de betões

Dissertação de mestrado em Construção e Reabilitação Sustentáveis

Advances in thermoplastic pultruded composites

Pultrusion is a versatile continuous high speed production technology allowing the production of fibre reinforced complex profiles. Thermosetting resins are normally used as matrices in the production of structural constant cross section profiles. Although only recently thermoplastic matrices have been used in long and continuous fibre reinforced composites replacing with success thermosetting matrices, the number of their applications is increasing due to their better ecological and mechanical performance. Composites with thermoplastic matrices offers increased fracture toughness, higher impact tolerance, short processing cycle time and excellent environmental stability. They are recyclable, post-formable and can be joined by welding. The use of long/continuous fibre reinforced thermoplastic matrix composites involves, however, great technological and scientific challenges since thermoplastics present much higher viscosity than thermosettings, which makes much difficult and complex the impregnation of reinforcements and consolidation tasks. In this work continuous fibres reinforced thermoplastic matrix towpregs were produced using equipment developed by the Institute for Polymers and Composites (IPC). The processing of the towpregs was made by pultrusion, in a developed prototype equipment existing in the Engineering School of the Polytechnic Institute of Porto (ISEP). Different thermoplastic matrices and fibres raw-materials were used in this study to manufacture pultruded composites for commercial applications (glass and carbon fibre/ polypropylene) and for advanced markets (carbon fibre/Primospire®). To improve the temperature distribution profile in heating die, different modifications were performed. In order to optimize both processes, towpregs production and pultruded composites profiles were analysed to determine the influence of the most relevant processing arameters in the final properties. The final pultruded composite profiles were submitted to mechanical tests to obtain the relevant properties.

Understanding the dispersion of fillers in polymer matrices

Understanding the mixing process of complex composite materials is fundamental in several industrial processes. For instance, the dispersion of fillers in polymer melt matrices is commonly employed to manufacture polymer composites, using a twin-screw extruder. The effectiveness of the filler dispersion depends not only on the complex flow patterns generated, but also on the polymer melt rheological behavior. Therefore, the availability of a numerical tool able to predict mixing, taking into account both fluid and particles phases would be very useful to increase the process insight, and thus provide useful guidelines for its optimization. In this work, a new Eulerian-Lagrangian numerical solver is developed OpenFOAM® computational library, and used to better understand the mechanisms determining the dispersion of fillers in polymer matrices. Particular attention will be given to the effect of the rheological model used to represent the fluid behavior, on the level of dispersion obtained. For the Eulerian phase the averaged volume fraction governing equations (conservation of mass and linear momentum) are used to describe the fluid behavior. In the case of the Lagrangian phase, Newton’s second law of motion is used to compute the particles trajectories and velocity. To study the effect of fluid behavior on the filler dispersion, several systems are modeled considering different fluid types (generalized Newtonian or viscoelastic) and particles volume fraction and size. The results obtained are used to correlate the fluid and particle characteristics on the effectiveness of mixing and morphology obtained.