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- Economic trade-off in the optimization of carrier aggregation with enhanced multi-band scheduling in LTE-Advanced scenariosPublication . Robalo, Daniel; Velez, FernandoThis work proposes Long Term Evolution-Advanced (LTE-A) integrated Common Radio Resource Management (iCRRM) for inter-band carrier aggregation (CA) between band 7 (2.6 GHz) and band 20 (800 MHz), considering bandwidths of 5 and 20 MHz. The iCRRM entity performs component carrier (CC) scheduling and increases user’s quality of service and experience while considering mobile video traffic. The performance from a new enhanced multi-band scheduling (EMBS) algorithm is compared to the one from a basic multi-band scheduler (BMBS), an integer programming-based general multi-band scheduling (GMBS) and the case without CA. EMBS involves reduced optimization scheduling complexity and allows the allocation of UEs to one or both CCs simultaneously, whereas both BMBS and GMBS only support one CC per UE. Simulations results have shown that, for 5 MHz CCs and cell radius equal to 1,000 m, with EMBS and GMBS, the 3GPP and ITU-T’s 1% packet loss ratio (PLR) threshold is only exceeded above 58 UEs (goodputs of 7.48 and 7.40 Mbps, respectively), while with BMBS only 54 UEs (6.9 Mbps) are supported. Without CA, the minimum obtained PLR is approximately 2%. For CCs with bandwidth of 20 MHz, only EMBS has been considered. The PLR threshold is not exceeded up to 40 users and the value of QoE raises from 2.86 (for 5-MHz bandwidth) to 3.96, while a gain of 9.56 occurs in supported goodput, increasing from 7.48 to 71.53 Mbps. Results from the cost/revenue trade-off have shown substantial improvements by using CA. Although the profit increases as the price per megabyte increases, it is verified that prices can be much lower if a bandwidth of 20 MHz is available. Assuming values for the supported goodput under the PLR ≤1% range and 20 MHz CCs, it has been shown that the percentage of profit decreases at a considerably higher rate (compared to 5-MHz bandwidth), due to the lower rate of decrease from the curve for costs. Considering PLR ≤1%, the profit curve for 20 MHz CCs at 0.001 € /MByte is similar to the one for 5 MHz CCs and price of 0.01 € /MByte for the smallest cell sizes (few hundreds of meters) but starts to decrease faster for larger cells.
- Carbon Fiber Epoxy Composites for Both Strengthening and Health Monitoring of StructuresPublication . Salvado, Rita; Lopes, Catarina; Szojda, Leszek; Araújo, Pedro; Górski, Marcin; Velez, Fernando; Castro-Gomes, João; Krzywon, RafalThis paper presents a study of the electrical and mechanical behavior of several continuous carbon fibers epoxy composites for both strengthening and monitoring of structures. In these composites, the arrangement of fibers was deliberately diversified to test and understand the ability of the composites for self-sensing low strains. Composites with different arrangements of fibers and textile weaves, mainly unidirectional continuous carbon reinforced composites, were tested at the dynamometer. A two-probe method was considered to measure the relative electrical resistance of these composites during loading. The measured relative electrical resistance includes volume and contact electrical resistances. For all tested specimens, it increases with an increase in tensile strain, at low strain values. This is explained by the improved alignment of fibers and resulting reduction of the number of possible contacts between fibers during loading, increasing as a consequence the contact electrical resistance of the composite. Laboratory tests on strengthening of structural elements were also performed, making hand-made composites by the “wet process”, which is commonly used in civil engineering for the strengthening of all types of structures in-situ. Results show that the woven epoxy composite, used for strengthening of concrete elements is also able to sense low deformations, below 1%. Moreover, results clearly show that this textile sensor also improves the mechanical work of the strengthened structural elements, increasing their bearing capacity. Finally, the set of obtained results supports the concept of a textile fabric capable of both structural upgrade and self-monitoring of structures, especially large structures of difficult access and needing constant, sometimes very expensive, health monitoring.
- Geometric modeling, simulation, and visualization methods for plasmid DNA moleculesPublication . Raposo, Adriano Nunes; Gomes, Abel João PadrãoPlasmid DNA molecules are a special type of DNA molecules that are used, among other applications, in DNA vaccination and gene therapy. These molecules are characterized by, when in their natural state, presenting a closed-circular conformation and by being supercoiled. The production of plasmid DNA using bacteria as hosts implies a purification step where the plasmid DNA molecules are separated from the DNA of the host and other contaminants. This purification process, and all the physical and chemical variations involved, such as temperature changes, may affect the plasmid DNA molecules conformation by uncoiling or even by open them, which makes them useless for therapeutic applications. Because of that, researchers are always searching for new purification techniques that maximize the amount of supercoiled plasmid DNA that is produced. Computer simulations and 3D visualization of plasmid DNA can bring many advantages because they allow researchers to actually see what can happen to the molecules under certain conditions. In this sense, it was necessary to develop reliable and accurate geometric models specific for plasmid DNA simulations. This dissertation presents a new assembling algorithm for B-DNA specifically developed for plasmid DNA assembling. This new assembling algorithm is completely adaptive in the sense that it allows researchers to assemble any plasmid DNA base-pair sequence along any arbitrary conformation that fits the length of the plasmid DNA molecule. This is specially suitable for plasmid DNA simulations, where conformations are generated by simulation procedures and there is the need to assemble the given base-pair sequence over that conformation, what can not be done by conventional predictive DNA assembling methods. Unlike traditional molecular visualization methods that are based on the atomic structure, this new assembling algorithm uses color coded 3D molecular surfaces of the nucleotides as the building blocks for DNA assembling. This new approach, not only reduces the amount of graphical objects and, consequently, makes the rendering faster, but also makes it easier to visually identify the nucleotides in the DNA strands. The algorithm used to triangulate the molecular surfaces of the nucleotides building blocks is also a novelty presented as part of this dissertation. This new triangulation algorithm for Gaussian molecular surfaces introduces a new mechanism that divides the atomic structure of molecules into boxes and spheres. This new space division method is faster because it confines the local calculation of the molecular surface to a specific region of influence of the atomic structure, not taking into account atoms that do not influence the triangulation of the molecular surface in that region. This new method also guarantees the continuity of the molecular surface. Having in mind that the aim of this dissertation is to present a complete set of methods for plasmid DNA visualization and simulation, it is also proposed a new deformation algorithm to be used for plasmid DNA Monte Carlo simulations. This new deformation algorithm uses a 3D polyline to represent the plasmid DNA conformation and performs small deformations on that polyline, keeping the segments length and connectivity. Experiments have been performed in order to compare this new deformation method with deformation methods traditionally used by Monte Carlo plasmid DNA simulations These experiments shown that the new method is more efficient in the sense that its trial acceptance ratio is higher and it converges sooner and faster to the elastic energy equilibrium state of the plasmid DNA molecule. In sum, this dissertation successfully presents an end-to-end set of models and algorithms for plasmid DNA geometric modelling, visualization and simulation.
- Cistercian Monastery of S. Bento de Cástris, Évora, Portugal: Acoustic measurements under ORFEUS ProjectPublication . Lanzinha, João; Nepomuceno, Miguel; Martins, Ana Maria Tavares; Reis, Carla Patrícia Lopes dos; Alves, Albino da Ascensão dos SantosThe Church of the Monastery of S. Bento de Cástris in Évora (13th- 19th centuries) presents an unusual space setting which seems to favour different positions for coral groups supporting liturgical and musical expression activities. These options are possibly of an empirical nature, since the scientific knowledge in the field of building physics and in particular of building acoustics are relatively recent. It is important to explore, with on-site measurements, the actual conditions of acoustic behaviour and in particular meet the reverberation times. Consequently, results obtained must be compared with the current recommendation for this type of space. This article characterises the Church in terms of its conception and its most relevant constructive aspects. The interest in measuring reverberation time, in this type of enclosed space, is also discussed. Such results of reverberation time measurements are presented and analysed for the different spaces of the Church. Finally, the findings of the study are presented as well as some hypotheses for future work in terms of acoustic analysis of Cistercian spaces and for a better understanding of the architecture and music relationship, in its different expressions.
- High-energy diets and Diabetes Mellitus: a threat for male fertilityPublication . Rato, Luís Pedro Ferreira; Oliveira, Carlos Pedro Fontes; Cavaco, José Eduardo Brites; Duarte, Ana Isabel MarquesA sobrevivência do ser humano reside numa fertilidade saudável, no entanto, nos últimos anos tem-se observado um declínio na fertilidade masculina. Este problema tem particular incidência nas sociedades modernas, e a curto prazo estará presente nos países em desenvolvimento. Factores externos associados ao estilo de vida, tais como maus hábitos alimentares, particularmente a ingestão excessiva de dietas de alta energia, têm contribuído para o aumento de doenças metabólicas, nomeadamente a obesidade e a diabetes mellitus (DM). Na verdade, a combinação de factores como: mudanças na composição de alimentos; aumento do consumo de dietas de alta energia; consumo de alimentos com altos níveis de açúcar e gorduras saturadas de elevada palatibilidade; o sedentarismo e a falta de atividade física são a principal causa para o incremento destas patologias. A obesidade e a DM são problemas de saúde pública nos países desenvolvidos e a sua incidência tem vindo a aumentar rapidamente entre os homens em idade reprodutiva, contribuindo para o surgimento da subfertilidade e infertilidade nesses indivíduos. A desregulação metabólica e endócrina associada a estes estadios patológicos compromete a função reprodutora masculina, uma vez que o eixo hipotálamo-hipófise-testículo, também conhecido como eixo reprodutivo, é sensível a alterações metabólicas. O tecido testicular é composto por uma população heterogénea de células somáticas e germinativas. As células germinativas estão dependentes do apoio nutricional fornecido pelas células de Sertoli, e distúrbios metabólicos podem perturbar essa cooperação metabólica. O metabolismo das células testiculares, em particular o das células de Sertoli, apresenta características únicas, uma vez que estas células são capazes de metabolizar vários substratos (e.g.: glucose, ácidos gordos, corpos cetónicos). As células de Sertoli metabolizam preferencialmente a glucose, sendo que a maioria desta é convertida a lactato, e não oxidada através do ciclo de Krebs. Os mecanismos que regulam o metabolismo das células de Sertoli são essenciais para a espermatogénese, e este processo metabólico é controlado por vários fatores, entre eles a insulina e as hormonas esteróides sexuais. Doenças metabólicas, como a DM, apresentam na sua origem resistência à insulina e/ou ausência de insulina, bem como uma incapacidade de as células responderem de forma eficiente à estimulação por esta hormona. Dada a importância da insulina no metabolismo da glucose e o facto de as células de Sertoli expressam receptores específicos para esta hormona, avaliámos o comportamento metabólico das células de Sertoli em situações de privação de insulina. Nestas condições, as células de Sertoli alteram o seu metabolismo glicolítico, diminuíndo a taxa de produção de lactato através da modulação da expressão de proteínas associadas à produção e exportação de lactato, sugerindo que são afectadas na sua actividade metabólica em condições patológicas associadas à desregulação da insulina, como é o caso da DM. No entanto, a DM induz uma desregulação endócrina generalizada. Uma consequência directa da DM na função testicular é a inibição da síntese de testosterona (T). Neste trabalho, demonstramos que os esteróides sexuais, particularmente a testosterona (e o seu metabolito 5α-di-hidrotestosterona) e o 17β-estradiol (E2), modulam o metabolismo glicolítico das células de Sertoli, favorecendo o consumo de glucose, sem contudo promoverem a síntese de lactato. De facto, a produção de lactato, que é o principal substrato para o desenvolvimento das células germinativas, encontrava-se diminuída pela acção androgénica, o que poderá resultar num comprometimento da cooperação metabólica testicular. Quanto mais severo é o estado de progressão da DM, maior é a redução dos níveis da T. Desta forma, estudámos os efeitos da desregulação dos níveis da T induzidos por diferentes estadios da DM, pré-diabetes e diabetes mellitus tipo 2 no metabolismo glicolítico das células de Sertoli. Os resultados mostraram que quanto mais avançado é o estado da doença, mais a via glicolítica está comprometida, verificando-se igualmente uma alteração mais acentuada na maquinaria celular associada à produção de lactato em células em cultura com níveis de T associados à diabetes mellitus tipo 2. Curiosamente, as células de Sertoli em cultura em condições de T similares ao observado no estado de diabetes mellitus tipo 2 mostram que são capazes de adoptar mecanismos que promovem o uso de substratos alternativos, como é o caso do glicogénio. Ao nível do testículo, evidenciou-se que o estado de pré-diabetes induzido pelo consumo de dietas de alta energia também altera o metabolismo glicolítico. Nestas condições, a via glicolítica está favorecida devido ao aumento da expressão e actividade de proteínas essenciais que intervêm nessa via metabólica. Também a expressão de proteínas associadas à produção de lactato está aumentada, o que parece contribuir para o aumento observado no lactato testicular. No entanto, e apesar da adaptação metabólica evidenciada, os parâmetros reprodutivos são seriamente afectados, o que pode resultar do favorecimento de um ambiente testicular oxidativo. De facto, nessas condições observou-se uma diminuição significativa da expressão de proteínas envolvidas tanto na manutenção da biogénese mitocondrial, como na activação do sistema de defesa contra as espécies reactivas de oxigénio. O potencial antioxidante testicular diminuído, assim como, a alteração na respiração mitocondrial testicular contribuíram igualmente para uma deficiente capacidade bioenergética e um aumento do ambiente oxidativo. Já em estadios mais avançados da DM, como é o caso da diabetes mellitus tipo 2, observou-se que o metabolismo glicolítico testicular é seriamente comprometido. A actividade da lactato desidrogenase está severamente diminuída, contribuindo para uma diminuição do conteúdo em lactato neste tecido. Porém, nestas condições destaca-se a adaptação verificada no metabolismo testicular, que promoveu um aumento do conteúdo de glicogénio nos testículos. Estes resultados indicam que a diabetes mellitus tipo 2 induz uma reprogramação metabólica testicular, promovendo vias metabólicas alternativas. No entanto, os parâmetros espermáticos dos indivíduos que sofriam desta condição estavam comprometidos, visto que a motilidade e viabilidade dos espermatozóides estavam acentuadamente diminuídas e o número de espermatozóides com anomalias na morfologia era elevado. Em conclusão, este trabalho demonstra que as doenças metabólicas, particularmente a DM, podem contribuir para uma diminuição do potencial reprodutivo masculino induzindo alterações profundas no metabolismo celular do testículo, e em particular no metabolismo das células de Sertoli. O processo da espermatogénese é complexo e, do ponto de vista fisiológico, o metabolismo glicolítico é essencial para o sucesso deste evento celular. A regulação do metabolismo da glucose nas células de Sertoli é alvo de vários factores, e tanto nos estadios iniciais da DM, como nos estadios mais avançados, sofre alterações, sendo que são mais pronunciadas em estadios avançados da doença. De facto, verificou-se que em estadios iniciais da DM o metabolismo testicular tende a adaptar-se de modo a assegurar a produção de lactato para as células germinativas em desenvolvimento. Todavia com a progressão da doença, a produção desse metabolito energético é seriamente comprometida. De facto, estas alterações metabólicas progressivas estão ainda associadas a uma diminuição dos parâmetros espermáticos, que seguramente serão responsáveis pelo declínio da saúde reprodutiva masculina.
- Modification of microfiltration membranes by hydrogel impregnation for pDNA purificationPublication . Castilho, Pedro Henrique Barata; Correia, Tiago R.; Amorim, Maria T. Pessoa de; Escobar, Isabel; Queiroz, João; Correia, Ilídio Joaquim Sobreira; Morão, AntónioThe huge efforts for the achievement of highly purified biomolecules are growing every day. A great number of efficient techniques, such as chromatography, are already available in laboratory for separation processes. However, membrane‐based technologies are the best match to assure simplicity, efficiency and easy scale‐up procedures. Herein we report the modification of a commercial microfiltration membrane for plasmid DNA purification by agarose gel impregnation. The membrane was characterized by SEM, ATR‐FTIR, EDS, contact angle, and porosity measurements. Additionally, the membrane pore radius was estimated from observed rejections of different proteins and with that information the rejection of a 6050 bp plasmid DNA (pDNA) molecule was estimated for different values of flux using a theoretical model of large flexible molecules in membranes with parallel cylindrical pores, which is applicable to pDNA ultrafiltration in conventional membranes, as recently shown in the literature. The experimental results show that the modified membrane has higher pDNA rejections than the predicted by the model, suggesting that the different type of porous structure that a hydrogel has, may have a positive effect on pDNA rejections as compared to other biomolecules with more rigid structures, making this type of modified membranes potential better candidates to be used for the selective recovery of pDNA in this type of bioprocesses.
- Prevalence of Dental Caries and Fissure Sealants in a Portuguese Sample of AdolescentsPublication . Veiga, Nélio Jorge; Pereira, Carlos; Ferreira, Paula; Correia, Ilídio Joaquim SobreiraIntroduction The aims of this study were to assess the prevalence of dental caries and the DMFT index, as well as the distribution pattern of pit and fissure sealants on permanent teeth in a Portuguese sample of adolescents, and to assess whether the existing usage of sealants and socio-demographic factors are correlated to caries prevalence on the examined sample. Materials and Methods A cross-sectional study was designed with a sample of 447 adolescents aged 12 to 18 years old, attending a public school in Sátão, Portugal. A self-administered questionnaire with questions about oral health behaviours and socio-economic status was answered by adolescents in the classroom. Clinical examination of oral health status and assessment of fissure sealants were accomplished by only one trained member of the research team. Results We obtained a DMFT index of 3.32 (2.92), which indicates a moderate level of prevalence of dental caries. When considering a DMFT = 0, we found significant statistical differences between the parents´ level of education (≤ 4th grade = 26.3 vs 5th–12th grade = 18.8 vs <12th grade = 43.3, p = 0.001), gender (male = 27.3 vs female = 19.6, p = 0.04), age (≤15 years = 27.1 vs <15 years = 18.5, p = 0.02), presence of fissure sealants (yes = 30.6 vs no = 13.5, p = 0.001) and experience of dental pain (no = 25.4 vs yes = 16.8, p = 0.02). When analyzing the prevalence of fissure sealants, we verified that 58.8% of adolescents had at least one fissure sealant applied. Significant statistical differences were found when analyzing the presence of fissure sealants related with parents´educational level (<9th grade, OR = 1.56 CI95% = 1.05–2.54), gender (female, OR = 1.86 CI95% = 1.19–2.98), experience of dental pain (yes, OR = 0.62 CI95% = 0.39–0.97) and presence of dental caries (yes, OR = 0.35 CI95% = 0.19–0.65). Conclusions The moderate level of caries prevalence reveals the need of improvement of primary prevention interventions among Portuguese adolescents. The establishment of a more targeted preventive program with better and more effective oral health education is essential, having into account socio-demographic aspects.