Lipschutz ulcers: uncommon diagnosis of vulvar ulcerations

Aetiological diagnosis of genital ulcers is still a challenge in clinical practice. The cause is mostly infectious, but it may otherwise be a presentation of a wide variety of pathologies, such as autoimmune (eg, Behçet’s disease), cancer or inflammatory processes. The Lipschütz ulcer is a non-sexually transmitted condition

Análise do processo de fabrico de vinagres

Mestrado em Engenharia Alimentat - Processamento de Alimentos - Instituto Superior de AgronomiaIt was intended to analyse the entire production process from the arrival of the vinegar factory production, through acetous fermentation, and most actively in the advanced stages to the storage of the finished vinegar. In attempt of the continuous improvement of the vinegars quality, there were investigated the factors that are capable to reduce the quality of this product, ended up in imperfections, like the presence of oxygen and high temperature, in different stages of the global productive process. For this, it was proceeded to a first identification and quantification of defects in stored samples, and further studies which tested the effect of this potential derogatory factors, such as temperature and oxygen, essentially in white wine vinegar, and red wine. The experiments included macroscopic and microscopic observation of bottled vinegars, as well as physico-chemical and microbiological analyses, mostly with regard to the activity of acetic bacteria. The results appearances that this derogatory factors (oxygen and high temperature) are difficult to control. Conclusive results revealed that the vinegar was spoil if exposed to oxygen and high temperature

Analysis of functional Magnetic Resonance data for neurosurgical planning: subject specific resting state analysis as a complement to task based analysis

Brain and other central nervous system tumors are the 17th most common cancer type in Europe, being associated with high mortality rate. Neurosurgery has been the ultimate solution for the treatment of brain tumors. Integration of preoperative brain mapping in the process is highly recommended in order to preserve fundamental areas of the brain, especially those believed to be connected to language and movement. Recently, there has been a growing interest in presurgical planning resorting to restingstate functional magnetic resonance imaging (fMRI). The aim of this thesis is to explore strategies to process data of resting-state fMRI in order to better understand its connection to task brain networks, and to assess their application to the protocols currently used within clinical institutions that are partners of the host scientific institution in an ongoing project. A total of 8 subjects were recruited to participate in this study, all of them previously referred for surgical tumor resection. An optimal strategy for pre-processing was devised and tested. Task data was processed using the General Linear Model, while rest data was processed through Independent Component Analysis. The processed data were then correlated via similarity coefficients. The results of similarity tests show a limited coincidence between resting-state networks and the activation task areas. Further studies will be required in order to improve these results

Relacionamento empresa/cliente no mundo digital : uma abordagem

Dissertação de Mestrado, Ciências Económicas e Empresariais, 13 de Janeiro de 2017, Universidade dos Açores.Os social media revolucionaram os meios de comunicação e a forma como as empresas interagem com os seus consumidores. O consumidor evoluiu e modificou a forma como busca informação antes da tomada de decisão de compra. A restauração tem sentido o alterar deste comportamento, quer pelo aumento da exigência dos consumidores, quer pela procura de validações de terceiros antes mesmo de procurarem o estabelecimento de restauração. O objetivo do presente trabalho consiste na busca de respostas de quem são estes novos consumidores e como eles estão presentes nos social media. Para tal, procurasse não só indagar os internautas sobre as suas motivações, mas também verificar as dinâmicas existentes dentro de uma rede social temática. Assim, consegue-se traçar o retrato do peso que os social media têm na tomadas de decisão de estratégia de comunicação das empresas e, também, o que são comunidades virtuais temáticas e quem nelas participa. O tipo de investigação adotado neste estudo foi do tipo quantitativo de natureza descritiva, recorrendo-se à recolha direta de conteúdo na rede social Facebook, na comunidade temática e ao método de questionário online. Foram obtidos 100 questionários válidos, os quais fornecem um conjunto de perceções sobre a utilização desses das comunidades virtuais temáticas. A análise de clusters foi realizada recorrendo ao método Kmeans Clusters, de forma a verificar as hipóteses de estudo. Os resultados apontam para a existência de diferentes perfis de utilizadores dentro da comunidade virtual temática, com diferentes motivações de presença, sendo que o fator em comum é o de comida como comunidade.ABSTRACT: Social media have revolutionized communication and the way in which companies interact with their consumers, and consumers have evolved and changed their way of searching information before making a purchasing decision. The restaurant industry has felt this change in behavior through increased consumer demands or third-party validation before consumers make a dining choice. The aim of this work is to identify these new consumers and how they are presented in social media. To this end, the study seeks not only to ask netizens about their motivations, but also to examine the existing dynamics within a thematic social network. By doing so, it is possible to trace the influence that social media have had in companies’ communication strategy decisions and also the thematic virtual communities and who is participating in them. The type of research used in this study is quantitative descriptive, employing the direct collection of content from the social network Facebook, the thematic community, and the online questionnaire method. We obtain 100 valid questionnaires, which provide a set of perceptions about the use of these thematic virtual communities. A cluster analysis is performed using k-means clustering to test the hypothesis. The results point to the existence of different user profiles within the virtual community theme, with different motivations for their presence, and suggest that common factors are the food of the community

Segurança e saúde na exploração de estações de tratamento de águas residuais da SIMTEJO

Actualmente a protecção do ambiente constitui um factor essencial para a qualidade de vida humana e até mesmo para a sobrevivência da vida no planeta. As Estações de Tratamento de Águas Residuais (ETAR) são infraestruturas importantes para o controlo da poluição da água, sendo particularmente relevantes para a protecção ambiental no seu todo. A SIMTEJO, empresa responsável pelo tratamento de águas residuais urbanas de cerca de 1,5 milhões de habitantes na região de Lisboa, tem por um dos seus principais objectivos a redução das descargas poluentes nos rios Tejo e Trancão. As ETAR são instalações industriais que processam água residual bruta, que pelas suas características particulares apresentam requisitos específicos no que diz respeito à segurança e saúde dos seus trabalhadores, nomeadamente no que diz respeito a riscos físicos, químicos e biológicos. O presente trabalho relata o estágio realizado SIMTEJO, inserido nas actividades em desenvolvimento na empresa com vista à sua certificação em Qualidade, Ambiente e Segurança. São apresentados os principais perigos e riscos a que são expostos os trabalhadores de uma ETAR e descreve-se, de uma forma geral, o que deve ser verificado para garantir o cumprimento da legislação em vigor em matéria de Segurança, Higiene e Saúde no Trabalho (SHST). Desenvolveu-se neste trabalho uma lista de verificação de aspectos de segurança destinada a apoiar auditorias internas da empresa, na análise da conformidade dos seus procedimentos operacionais à luz daquilo que a legislação obriga e recomenda

Produção de novos materiais de elevado desempenho a partir de celulose vegetal nano/microfibrilada

Cellulose is the most abundant, renewable and sustainable biopolymer on the planet, having many desirable characteristics that make it a suitable material for many applications. Cellulose fibrils from renewable resources have been gaining increasing interest due to their sustainable and biodegradable nature, combined with other mechanical, optical, thermal, and fluidic properties. Cellulose fibrils are therefore attractive for the production of a variety of materials, from composites to porous membranes and gels, filaments and films. The investigation developed throughout this work aimed to explore both the rheological behavior of nanofibrillated cellulose (NFC) suspensions using different liquid media, and mechanical, optical and barrier properties of structures produced from this material. Regarding the investigation of NFC suspensions’ rheological behavior, the undertaken study focused on the morphological effects of the fibrils present in aqueous suspensions, on the addition of ethanol or acetone to the medium and on the increase of the medium’s ionic strength through the addition of high NaCl concentrations. For this purpose, two different NFC suspensions were used: a carboxymethylated NFC aqueous suspension obtained from Innventia (Stockholm, Sweden) (NFC-carb); and a NFC aqueous suspension produced in the laboratory using a commercial eucalyptus bleached sulfite pulp, subjected to a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) mediated oxidation pretreatment in a TEMPO/NaBr/NaClO system, which was subsequently subjected to high pressure homogenization at the RAIZ (Institute for Research on Forest and Paper) facilities (NFC-TEMPO). The morphological analysis of the suspensions through SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy) allowed to infer a higher percentage of nanoelements in the NFC-TEMPO suspension compared to the NFC-carb. The physicochemical analysis of the fibrils on both suspensions was performed: the intrinsic viscosity was 397 ml/g for NFC-carb and 85 ml/g for NFC-TEMPO, corresponding to cellulose polymerization degrees of 696 and 149, respectively; the quantification of carboxylic groups was 698 μmol/g for NFC-carb and 1900 μmol/g for NFC-TEMPO. These results confirmed that the used suspensions were morphologically and physicochemically very different. In order to study the effect of the liquid medium’s characteristics in which the nanofibrils are suspended, on the rheology of the suspension, the addition of ethanol or acetone to the medium was explored, and concentrations between 2.5 and 40% of ethanol or acetone were investigated, using the NFC-carb. On the other hand, to study the effect of increasing ionic strength on the suspensions’ rheological behavior, NaCl was added in order to obtain concentrations between 50 mM and 1000 mM, for both studied nanofibrils (NFC-carb and NFC-TEMPO). The solids content of both studied suspensions was adjusted to 1.3%. The suspensions were subjected to rheological measurements in flow and oscillatory modes, using a tension-controlled rheometer, equipped with a cone and plate geometry, with either smooth or rough surfaces. In the later case, sandpaper with known roughness was attached to the surface of both tools. The study of the geometry roughness effect on the NFC-carb suspensions’ rheological behavior showed higher shear stresses and viscosity for the rough geometry at lower shear rates (0.05 to 5 s-1), but at higher rates (up to 100 s-1) the measurements were less influenced by either flow instabilities or the geometry’s roughness, closely representing the bulk properties of the suspension. The subsequent rheological measurements were carried out with sandpaper with a roughness of 58.5 μm. Regarding the study of ethanol or acetone addition effect on the NFC-carb suspension, results showed that an addition of 2.5 wt.% of either solvent decreased the viscosity and dynamic modulus, while a 40 wt.% addition increased the shear stress for values higher than those of the corresponding aqueous suspensions, particularly at low or moderate shear rates, indicating higher interfibrillar interaction. The suspension containing 40wt.% ethanol enabled to further double the storage modulus and allowed the extension of the gel-like behavior to higher shear stress values. Concerning the effect of ionic strength, increasing the NaCl concentration from 50 mM to 100 mM drastically increased the viscosity of both NFC-carb and NFC-TEMPO suspensions, while the network’s energy storage modulus the in the elastic region linearly increased with the increase of NaCl concentration from 100 mM to 1000 mM, suggesting improved interfibrillar interaction with increasing salt concentration. This result is in agreement with the expected decrease in electrostatic repulsion between fibrils due to salt addition. In practical terms, the suspensions elastic domain was extended from 10 Pa to 50 Pa with the addition of 40 wt.% of acetone, and to above 500 Pa with NaCl addition at a concentration of 1000 mM. Despite the much lower cellulose degree of polymerization of the NFC-TEMPO sample, compared to that of the NFC-carb (149 vs 696), the NFC-TEMPO aqueous suspension without added salt exhibited a markedly higher shear stress over the entire studied shear rate range. This result evidences the importance of particle size, as well as specific surface area, on the suspension’s rheological behavior, as the NFC-TEMPO sample has a higher nanoelements (nanofibrils) content than the NFC-carb (based on SEM and TEM analysis). In addition to film production, NFC gel can be used to produce filaments for potential applications in the textile industry. In the present work, the effect of suspension’s solids content and spinning rate on the mechanical properties of filaments produced via wet spinning were studied. For this purpose, two commercial eucalyptus bleached pulps, one obtained by a kraft process and the other one obtained by a sulfite process, were used as sources of cellulose fibers to produce NFC suspensions. Firstly, both pulps were submitted to a refining process in a PFI mill. Then, the refined sulfite pulp was subjected to TEMPO-mediated oxidation in a TEMPO/NaBr/NaClO system, while the refined kraft pulp was subjected to TEMPO-mediated oxidation in a TEMPO/NaClO/NaClO2 system. Both oxidized pulps were subsequently subjected to high pressure homogenization in the RAIZ facilities. The initial characteristics of the pulps and the different applied oxidative treatments led to products with very different degrees of cellulose polymerization. For the sulfite pulp, the cellulose degree of polymerization in the NFC-s was 202, while the NFC resulting from kraft pulp (NFC-k) had a cellulose degree of polymerization of 848. The highest cellulose degree of polymerization of the NFC-k is a consequence of the higher initial value of the pulp and also the less aggressive oxidation treatment with the TEMPO/NaClO/NaClO2 system. The suspensions’ solids content was adjusted to a range from 2.5 to 3.22 % and were used to produce cellulosic filaments via wet spinning, with spinning rates of 0.45 to 1.7 m min-1 into a 1M NaCl coagulation bath, followed by an ethanol fixation bath. Some of the produced filaments were also subjected to an additional water bath, in order to wash out the salt still present in the filaments. The filaments ends were pinned, maintaining the filaments’ length and were air dried under standard conditions of temperature and relative humidity. Subsequently, filaments’ mechanical performance was tested. The filaments were void-free and had an approximately circular cross section, which was not substantially altered by the spinning rate variation in the studied range, nor by the reimmersion in the washing bath and second drying. The results showed that an increase in wet spinning rate improved the mechanical performance of the filaments, indicating some level of fibril alignment. On the other hand, the increase in the suspensions’ solids content did not translate into an improvement in the filaments’ strength, due to the higher viscosity and reduced alignment capacity of the fibrils. The filaments produced from the NFC-s suspension exhibited superior mechanical performance, despite the much lower cellulose degree of polymerization. On the other hand, the microscopic analysis of the suspension shows a higher fibrillation extent and a higher nanoelements content, which again highlights the role of fibril morphology in the structure/performance of the filaments. After additional washing of the filaments, and as a consequence of removing some amount of salt, the linear mass and cross-sectional diameter of the filaments significantly decreased, thus a drastic increase in tensile strength, tenacity and strength-to-failure was observed due to interfibrillar interaction reestablishment. A broader and deeper exploration of filaments production from NFC gels requires a more advanced experimental setup, namely one that allows to increase the spinning rate, which was not available. With regard to cellulose films, in addition to mechanical properties, barrier properties are very important in several applications. Thus, at a given stage of the undertaken work, the effect of hot calendering on the physical and water vapor barrier properties of bacterial and vegetable cellulosic films was studied. The production of bacterial cellulose was carried out using Gluconacetobacter xylinus at the University of Minho facilities and the films were produced and tested at the University of Beira Interior. To produce the films, bacterial cellulose was fragmented in a blender and the solid content of the resulting suspension was adjusted to 0.354 %. Part of this suspension was subjected to ozonization in order to improve the optical properties of the resulting films. Films were produced by vacuum filtration from non-ozonized (BC) and ozonized (BCO) bacterial cellulose suspensions. After draining the water, the filter cakes were adhered to metal discs and pressed between blotting papers using a procedure analogous to paper production. Then, the films were dried overnight, between perforated metal rings under pressure applied to the ends of the sheets to prevent the films from shrinking, under standard conditions of temperature and relative humidity. For properties comparison, vegetable cellulose films were also produced from highly refined bleached kraft eucalyptus pulp with approximately the same grammage as the bacterial cellulose films. To study the calendering effect, some films were subjected to a hot calendering process. Results showed that BC and BCO suspensions formed much denser films than those from vegetable cellulose, forming much more compact and closed structures, in agreement with the smaller dimension of the constituent elements. As a consequence of the high density, the Young's modulus and tensile index of BC and BCO films were much higher than those obtained for vegetable cellulose. Calendering substantially increased the transparency of the films and ozonation was effective in increasing the brightness and transparency of the BCO films regarding the BC films. However, both processes slightly decreased the mechanical performance of the films. The water vapor transfer rate was lower for bacterial cellulose films than for vegetable cellulose films and decreased by 70% with calendering. Concluding, hot calendering can be used to obtain bacterial cellulose (or nanofibrillated vegetable cellulose) films suitable for various applications, where the water vapor barrier represents an important functionality. Ozonation can be used as a way to improve the optical properties of the films, although it is necessary to establish a compromise between the benefits of ozonization and calendering, and the decrease in the mechanical performance of the films induced by these processes. Subsequently, research was carried out in order to provide hydrophobicity to films made from a NFC suspension, through coating with stearic acid (SA) and particles of modified precipitated calcium carbonate (PCC). The NFC used in this work, oxidized with a TEMPO/NaBr/NaClO system, contained a cellulose with a degree of polymerization of 367 and a carboxylic group content of 997 μmol/g. An SA aqueous suspension was prepared following a procedure that involved raising the temperature of a SA/water mixture and sonicating it, followed by cooling in an ice bath. The modification of the PCC was carried out by adding PCC to the priorly made SA suspension and subjecting it to ultrasounds. After drying in an oven, the modified PCC was collected and manually ground, resulting in a fine white powder. Both the SA aqueous suspension and the modified PCC were used as a coatings in the production of hydrophobic NFC films. The films were produced by vacuum filtration and later surface-modified, resulting in three different sets: a first set of neat, uncoated NFC films; a second set coated with a layer of stearic acid (NFC-SA) and a third set coated with a layer of stearic acid and an additional layer of modified PCC (NFC-LBL). The films were dried overnight, between perforated metal rings under pressure applied to the ends of the sheets, under standard conditions of temperature and relative humidity. Subsequently, some of the coated films were subjected to heat treatment in an oven at 68ºC or 105ºC. Next, the films were analyzed in terms of their mechanical performance, water vapor and oxygen barrier properties, as well as static/dynamic contact angle measurements. The results showed that the coatings and heat treatments did not affect the mechanical performance of the films. Heat treatments decreased the water vapor transmission rate and oxygen permeability of both NFC-SA and NFC-LBL films. Coating with SA rendered hydrophobic films as the measured static contact angle reached 122°. Non-heat-treated NFC-LBL films achieved a contact angle of up to 150º and a contact angle hysteresis of 3.1º. The NFC-LBL films treated at 68°C exhibited near superhydrophobicity, with a contact angle of up to 140° and a contact angle hysteresis of 5°. The coating of NFC-LBL films without heat treatment was easily removed by friction, but the heat treatment turned the films’ coating the hydrophobicity persistent, resisting to friction and handling. Taking into account that the production of nanofibrillated cellulose films through filtration is a slow process, based on previous rheology studies it was decided to study the effect of ethanol addition to the suspension on the drainage time during the production of NFC films by vacuum filtration and the mechanical, optical and barrier properties of the resulting films. For this, aqueous / alcoholic suspensions of NFC with an ethanol content up to 75 wt.% were used in the production of films, monitoring the drainage progression by measuring the collected filtrate. The films were air-dried under standard conditions of temperature and humidity or in an oven at 70ºC for 4 hours. Mechanical and optical performance as well as water vapor barrier properties were tested. The results showed that the filtration time drastically decreased with increasing ethanol content, from about 2 hours to 2 minutes for ethanol suspensions with 0 (zero) and 75 wt.%, respectively. The increase in ethanol content did not significantly affect the mechanical performance of air-dried films, despite the increase in the global porosity of the structures. On the other hand, oven drying provided the films with tensile properties superior to those exhibited by air-dried films, both produced from purely aqueous suspensions, despite the increase in elongation at break and the higher value of specific light scattering coefficient. The water vapor transmission rate increased for films produced from 75 wt.% ethanol suspensions and was even higher for oven dried films. The combination of drying the films in an oven and producing the film from an alcoholic/aqueous suspension provided the opportunity to manipulate the transparency of the film and the water vapor transmission rate, preserving the mechanical performance of the films. Briefly, with this study, it was possible to develop a relatively fast and simple method to produce NFC films with mechanical and barrier properties with potential for several applications, such as membranes, where mechanical strength, toughness, low density, controlled permeability and porosity and high specific area are important, fuel cells, liquid purification and filtration, tissue engineering, protein immobilization and separation, and protective clothing. In short, the investigation carried out throughout this work allowed to prove the great potential of cellulosic fibrils in numerous applications, mainly in the manufacture of films. Regarding calendering, the present work demonstrated that this unitary operation is highly effective in improving the water vapor barrier properties of cellulosic fibril films. With regard to the production of films by vacuum filtration from highly fibrillated cellulose suspensions, the most reported difficulty by several authors referenced in the literature is the fact that this is an extremely slow process, making the production of NFC films impractical at the industrial level. The present work presents important developments regarding this aspect, suggesting a simple modification from the purely aqueous medium of suspensions to a medium with a mixture of water/ethanol. This technique, in addition to drastically reducing film formation time and using a solvent that is easily and quickly recovered by evaporation, preserves the mechanical properties of the produced films. Another aspect that complicates the application of NFC in several areas and, consequently, of films made from NFC, is its hydrophilic nature. The present work developed methods for the production of NFC films with strong hydrophobic properties, resistant to handling and friction, applying surface coatings of stearic acid and precipitated calcium carbonate, combined with a heat treatment, in an environmentally friendly technique and possibly industrially scalable.A celulose é o biopolímero mais abundante, renovável e sustentável do planeta, possuindo muitas características desejáveis que a tornam um material adequado para diversas aplicações. As fibrilas de celulose obtidas a partir de recursos renováveis têm vindo a ganhar um crescente interesse devido à sua natureza sustentável e biodegradável, combinada com outras propriedades mecânicas, óticas, térmicas e fluídicas. As fibrilas de celulose são, portanto, atraentes para o fabrico de diversos materiais, desde compósitos a membranas porosas e géis, filamentos e filmes. A investigação desenvolvida ao longo deste trabalho visou explorar quer o comportamento reológico de suspensões de celulose nanofibrilada (NFC) usando diferentes meios líquidos, quer as propriedades mecânicas, óticas e de barreira das estruturas produzidas a partir deste material. Relativamente à investigação do comportamento reológico de suspensões de NFC, o estudo realizado focou-se nos efeitos da morfologia das fibrilas presentes em suspensões aquosas, na adição de etanol ou acetona ao meio e no aumento da força iónica do meio através da adição de elevadas concentrações de NaCl. Para tal, foram utilizadas duas suspensões diferentes de NFC: uma suspensão aquosa de NFC carboximetilada obtida através da Innventia (Estocolmo, Suécia) (NFC-carb); e uma suspensão aquosa de NFC produzida no laboratório usando uma pasta comercial de eucalipto ao sulfito branqueada, submetida a um pré-tratamento de oxidação mediada por 2,2,6,6-tetrametilpiperidina-1-oxil (TEMPO) num sistema TEMPO/NaBr/NaClO, que posteriormente foi submetida a homogeneização de alta pressão nas instalações do RAIZ (Instituto de Investigação da Floresta e do Papel) (NFC-TEMPO). A análise morfológica das suspensões através de SEM (Scanning Electron Microscopy) e TEM (Transmission Electron Microscopy) permitiu inferir uma maior percentagem de nanoelementos na suspensão NFC-TEMPO relativamente à NFC-carb. Foi efetuada a análise físico-química das fibrilas presentes em ambas as suspensões: a viscosidade intrínseca foi de 397 ml/g para a NFC-carb e 85 ml/g para a NFC-TEMPO, correspondendo a graus de polimerização da celulose de 696 e 149, respetivamente; a quantificação de grupos carboxílicos foi de 698 μmol/g para a NFC-carb e 1900 μmol/g para a NFC-TEMPO. Estes resultados confirmaram que as suspensões usadas tinham propriedades morfológicas e físico-químicas substancialmente diferentes. meio, tendo-se investigado concentrações entre 2,5 e 40% de etanol ou acetona, utilizando a NFC-carb. Por outro lado, para o estudo do efeito do aumento da força iónica no comportamento reológico das suspensões, foi adicionado NaCl com vista a obter concentrações entre 50 mM e 1000 mM, tendo-se estudado ambas as nanofibrilas (NFC-carb e NFC-TEMPO). O teor de sólidos das duas suspensões estudadas foi ajustado para 1,3 %. As suspensões foram submetidas a medições reológicas nos modos de fluxo contínuo e oscilatório, usando um reómetro controlado por tensão, equipado com uma geometria de cone e prato, com superfície lisa ou rugosa, sendo que, no caso da geometria rugosa, papel de lixa com rugosidade conhecida foi colado na superfície de ambas as peças. O estudo do efeito da rugosidade da geometria no comportamento reológico das suspensões NFC-carb evidenciou tensões de cisalhamento e viscosidade mais elevados para a geometria rugosa a taxas de cisalhamento mais baixas (0.05 a 5 s-1), mas a taxas mais elevadas (até 100 s-1) as medições foram menos influenciadas quer por instabilidades de fluxo, quer pela rugosidade da geometria, aproximando-se das

Study of the potential toxicity of adrenaline to neurons, using the SH-SY5Y human cellular model

Prolonged overexposure to catecholamines causes toxicity, usually credited to continuous adrenoceptor stimulation, autoxidation, and the formation of reactive pro-oxidant species. Non-differentiated SH-SY5Y cells were used to study the possible contribution of oxidative stress in adrenaline (ADR)-induced neurotoxicity, as a model to predict the toxicity of this catecholamine to peripheral nerves. Cells were exposed to several concentrations of ADR (0.1, 0.25, 0.5 and 1mM) and two cytotoxicity assays [lactate dehydrogenase (LDH) release and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction] were performed at several time-points (24, 48, and 96h). The cytotoxicity of ADR was concentration- and time-dependent in both assays, since the lowest concentration tested (0.1mM) also caused significant cytotoxicity at 96h. N-acetyl-cysteine (1mM), a precursor of glutathione synthesis, prevented ADR-induced toxicity elicited by 0.5mM and 0.25mM ADR following a 96-h exposure, while the antioxidant Tiron (100µM) was non-protective. In conclusion, ADR led to mitochondrial distress and ultimately cell death in non-differentiated SH-SY5Y cells, possibly because of ADR oxidation products. The involvement of such processes in the catecholamine-induced peripheral neuropathy requires further analysis

Strategic impact of social media in tourism

The main objectives of this dissertation are to find out if Social Media has any impact in Tourism, to determine what tourists’ perceived benefits of using social media when taking trips are, and to ascertain if there is any strategic opportunity for value creation for the tourist. A Social Media value-creation model is created in order to find out if any of the functionalities applied to tourism and any of the perceived benefits of using Social Media in tourism contribute in any way to the tourist’s value-creation or if it has an influence on tourists when planning and taking trips. Through a survey answered by 236 respondents, the most influential attributes of the usage of Social Media in tourism are ascertained, the travellers’ perception of social media is analyzed, the important functionalities and benefits are determined and an analysis of the strategic impact of Social Media in tourism is conducted. After analyzing the strategic impact of Social Media in tourism and applying the RBV model, it is concluded that Social Media does indeed have an impact in tourism. It can even be used as a source of sustainable competitive advantage if tourism firms develop a positive reputation and focus on the personalization of their services as the key element for their value-creating strategy.Os principais objectivos desta dissertação é descobrir se a Social Media tem algum impacto no turismo, para determinar quais os benefícios que os turistas consideram mais importantes quando usam Social Media quando planeiam viagens, e para perceber se há alguma oportunidade estratégica para a criação de valor para o turista. Um modelo de criação de valor de Social Media no turismo foi desenvolvido para descobrir se alguma das funcionalidades ou algum dos benefícios contribuem, de alguma maneira, para a criação de valor do turista ou se tem influência nos touristas quando planeiam viagens ou quando viajam. Através de um questionário respondido por 236 pessoas, são determinados os atributos mais influentes no uso de Social Media no turismo, é definida a percepção que os turistas têm do Social Media, as funcionalidades e benefícios mais importantes são explicados, e é feita uma análise do impacto estratégico de Social Media no turismo. Depois de analisar o impacto estratégico de Social Media no turismo e de aplicar o modelo de RBV, é concluído que o Social Media realmente tem impacto no turismo. Pode até ser utilizado para desenvolver uma vantagem competitiva sustentável se as empresas turísticas desenvolverem uma reputação positiva e se concentrarem-se na personalização dos seus serviços como elemento-chave para a criação de uma estratégia de criação de valor