Class III treatment strategies

Communication presented at the International Joint Congress of the Multiloop Edgewise Arch-Wire Technique and Research Foundation (IJC-MEAW). Seoul, Korea, 1-3 October 2014

ICT in Higher Education: a case-study of mediated blended-learning

Teaching in on-line and collaborative situations requires a variety of responses including changes in pedagogy as instructors taking the role of facilitators of information while guiding students toward solutions. In order for online learning to be successful, therefore, teachers as well as learners will need to explore new roles in the teaching-learning relationship. In this paper, the authors propose to examine how educators can mediate instruction by first designing their course goals and objectives and then consider how the on-line environment can best serve the instructional objectives and plan appropriate activities and assessment. We seek to explore the use of online environments as the bridge between real world and reflective knowledge

Oil-hydraulic power units - state of the art

Despite the evolution of electric drives and their undeniable advantages, hydraulic systems play an important role in today's technologies. Due to the ability to operate enormous power densities, industrial hydraulics are irreplaceable when large forces and binaries are required. Its importance can be characterized by the economy it represents and by the development potential associated with scientific interest. This paper summarizes the technologies used in the production of oil-hydraulic power, seeking to identify the trends of development and the research opportunities that come from the demands of the current developments.info:eu-repo/semantics/publishedVersio

A computerized tomography study of the morphological interrelationship between the temporal bones and the craniofacial complex

"This is the pre-peer reviewed version of the following article: Journal of Anatomy. Volume 220, Issue 6, pages 544–554, June 2012, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1111/j.1469-7580.2012.01499.x/pdf ""The hypothesis that the temporal bones are at the center of the dynamics of the craniofacial complex, directly influencing facial morphology, has been put forward long ago. This study examines the role of the spatial positioning of temporal bones (frontal and sagittal inclination) in terms of influencing overall facial morphology. Several 3D linear, angular and orthogonal measurements obtained through computerized analysis of virtual models of 163 modern human skulls reconstructed from Cone-beam Computed Tomography (CBCT) images were analyzed and correlated. Additionally, the sample was divided into two subgroups based on the median value of temporal bone sagittal inclination [anterior rotation group (n=82); posterior rotation group (n=81)], and differences between groups evaluated. Correlation coefficients showed that sagittal inclination of the temporal bone was significantly (p <0.01) related to midline flexion, transversal width, and anterior-posterior length of the basicranium, to the anterior-posterior positioning of the mandible and maxilla, and posterior midfacial height. Frontal inclination of the temporal bone was significantly related (p <0.01) to basicranium anterior-posterior and transversal dimensions, and to posterior midfacial height. In comparison with the posterior rotation group, the anterior rotation group presented a less flexed and anterior-posteriorly longer cranial base, a narrower skull, porion and the articular eminence located more superiorly and posteriorly, a shorter posterior midfacial height, the palatal plane rotated clockwise, a more retrognathic maxilla and mandible, and the upper posterior occlusal plane more inclined and posteriorly located. The results suggest that differences in craniofacial morphological are highly integrated with differences in the positional relationship of the temporal bones. The sagittal inclination of the temporal bone seems to have a greater impact on the 3D morphology of the craniofacial complex than frontal inclination.

Centric relation : a matter of form and substance

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.The recent review article by Zonnenberg, Türp and Greene ‘Centric relation critically revisited – What are the clinical implications’? opens an important debate by addressing topics of central relevance in Dentistry, namely the relationship between occlusion and the condyle-to-glenoid-fossa position, and the need for diagnostic assessment and therapeutic alteration of the condylar position in orthodontic patients. Zonnenberg, Türp and Greene concluded that the mandibular condyle is correctly situated in most orthodontic patients. Thus, in their view, orthodontists can disregard this aspect during treatment, and rely on the plastic properties of the masticatory supporting structures, while aiming at finishing the cases in a good occlusal relationship. We think that this approach fails to consider that biological variation of the stomatognathic structures can also be pathological and that, as dental occlusion determines condylar relative position within the glenoid fossa, changes in the occlusion are likely to alter the original condylar-to-glenoid-fossa relation. Hence, we claim that whenever the occlusal relationship must be changed, the clinician should carefully monitor the condyle position and the mandibular function to prevent possible iatrogenic effects. To advance the discourse on the topic, we invite Zonnenberg, Türp and Greene to clarify their definition of ‘average patient’ and their interpretation of ‘full-mouth orthodontic and orthognathic treatment’, their understanding of ‘biologically acceptable condylar relationship’, their justification of maximum intercuspation as reference position, the extent to which they think it is safe to rely on the TMJ resilience, and finally their alternative to centric relation in the treatment of patients needing condylar repositioning.info:eu-repo/semantics/publishedVersio

Projeto da estrutura e sistema de movimentação robotizado de linha automática de corte de chapa

Os robots de movimentação de chapa são bastantes úteis para as empresas de metalomecânica. De facto, cada vez mais existem máquinas de corte por jato de água, laser ou outros processos, nos quais os robots apresentam um papel importante na carga e descarga do material. O trabalho realizado apresenta novas soluções aos sistemas de movimentação existentes no mercado, e permite reduzir os custos na movimentação do material. Este projeto serve essencialmente para chapas em trajetória retilínea, e efetuar o seu levantamento do equipamento e deposição em estrutura de suporte (ou viceversa). A vantagem a ter em conta é a diminuição dos custos de movimentação do material. Neste trabalho apresentou-se a metodologia de dimensionamento de um robot automatizado que transporta chapas com um peso máximo de 3500 kg, tendo por base as normas do EC3-P1.8 e o Método de Elementos Finitos (MEF). No decurso do projeto foram abordadas os seguintes temas: Abordagem inicial da geometria através do Solidworks; Dimensionamento da estrutura por software de Elementos Finitos, o Solidworks; Dimensionamento das correntes, carretos/discos ou coroas e rolamentos; Dimensionamento e seleção dos moto-redutores, bomba de vácuo e ventosas; Cálculo das solicitações em cada membro da estrutura por software de análise estrutural, o Multiframe3D, e respetivo dimensionamento das ligações aparafusadas e soldadas; Elaboração dos desenhos de projeto finais, processos de fabrico e custos; Dimensionamento do acionamento, MG e disposição dos dispositivos no quadro elétrico. Como conclusão refere-se que se conseguiu realizar o projeto e obter uma solução final otimizada, com a ajuda de ferramentas importantes, como sejam o MEF, resultando num equipamento cujas solicitações para a estrutura e sistema de movimentação foram otimizadas, resultando num equipamento eficiente, robusto, seguro e de custo reduzido.Robots for moving plates are quite useful for metalworking companies. In fact, there are more and more machines, such as water jet cutting, laser or other processes in which these robots have an important role in the loading and unloading of the material. This work presents new solutions for the existing moving systems in the market, and enables cost savings in material handling. This project is essentially intended to move plates in a straight path, and provide their lifting and deposition in support structures (or vice versa). The advantage to account for is the decrease in the cost of material handling. This work presented the methodology for designing a robot that carries automated plates with a maximum weight of 3500 kg, based on the rules of Eurocode 3 and the Finite Element Method. In the course of the project, the following topics were addressed: Initial approach to the geometry through Solidworks; Structure design by finite element software, Solidworks; Design of the chains, sprockets/discs or crowns and bearings; Design and selection of gearmotors, vacuum pump and suction cups; Calculation of loads in each member of the structure by structural analysis software, Multiframe3D, and the respective design of bolted and welded connections; Preparation of final design drawings , manufacturing processes and costs; Design of the driving system, GRAFCET method and arrangement of the devices in the electrical board. As a conclusion it is stated that the project been achieved and optimized to obtain a final solution, with the help of important tools such as Finite Elements, resulting in a device whose requests for structure and motion system were optimized , resulting in an efficient, robust, secure and cost-effective equipment

Chemical and biological characterization of an aqueous Sambucus nigra L. flower extract

Dissertação de mestrado em BiotecnologiaAtualmente, há um crescente interesse no uso de recursos naturais como fonte de compostos bioativos, com potenciais benefícios para a saúde. Desde a antiguidade que é recorrente o uso plantas ao nível da medicina tradicional, nomeadamente a flor de sabugueiro (Sambucus nigra L.). Recentemente, esta planta tem sido a base de vários produtos nutracêuticos, contudo, ainda não existem evidências científicas claras que fundamentem a sua bioatividade, bem como os mecanismos celulares associados. De acordo com a literatura, os extratos de sabugueiro são constituídos sobretudo por compostos terpénicos voláteis, triterpénicos, esteróis, e compostos fenólicos. É, contudo, importante salientar que a composição de cada uma destas famílias é dependente do método de extração (solvente, temperatura e tempo). O principal objetivo deste estudo foi a caracterização química de um extrato aquoso de flor de sabugueiro e a sua validação como agente anticancerígeno. A extração aquosa da flor de Sabugueiro foi realizada a diferentes temperaturas (50, 70 e 90 ºC). O extrato aquoso obtido a 90 ºC apresentou a atividade anti-radicalar mais elevada (0.157 ± 0.001 mmol TE g-1) e uma concentração de compostos fenólicos mais elevada (45.32 ± 2.20 mg CAE g-1). As análises qualitativas e quantitativas de GC-MS e HPLC-MS do extrato aquoso de flor de sabugueiro permitiram identificar 46 compostos, sendo a quercetina e o ácido clorogénico representativos de 86 % da totalidade dos compostos fenólicos identificados na fração hidrofílica, e a naringenina (27.16 %) o composto maioritário na fração lipofílica. A atividade epigenética do extrato da flor de sabugueiro na desmetilação do MLH1 foi testada em combinação com o 5-fluorouracil em células do cancro colorretal (RKO), usando a 5-azacitidina como controlo positivo. Os resultados sugerem que a combinação do extrato de sabugueiro com o 5-FU não resulta num efeito sinergético, o que indica que o extrato não tem influência na desmetilação do MLH1. Apesar do extrato da flor sabugueiro ter diversas moléculas com capacidade antioxidante, o extrato não demonstrou proteção ou indução de reparação de danos do DNA após um insulto oxidativo (H2O2). Ao nível da atividade antimicrobiana, verificou-se que bactérias gram-positivas são mais suscetíveis à presença deste extrato, nomeadamente, Staphylococcus aureus clinicamente isolado e Staphylococcus epidermidis. Em conclusão, verificou-se que o extrato de flor de sabugueiro não possui capacidade de modular atividade epigénica e estimular a proteção/reparação de danos oxidativos. Ao invés, verificou-se que o extrato possui atividade microbiana, nomeadamente contra bactérias gram-positivas.Nowadays, there is a growing interest on the use of natural resources as sources of bioactive compounds with potential health benefits. Since the antiquity, that is recurrent the use of plants in folk medicine, such as the elderflower (Sambucus nigra L.). Recently, this plant has been the basis of several nutraceutical products. Thus, there is not a clear scientific explanation for its bioactivity, as well as the responsible cellular mechanisms. According to the literature, elderflower extracts are mainly composed by volatile terpenic, triterpenic, sterols and phenolic compounds. However, the composition of each one of this families will be dependent of extraction method (solvent, temperature, time). The main gold of this study was the chemical characterization of an aqueous elderflower extract and its validation as an anticarcinogenic agent. The aqueous extraction of elderflower was performed at different temperatures (50,70 and 90 ºC). The aqueous extract obtained at 90 ºC exhibited the highest antiradical activity (0.157 ± 0.001 mmol TE g-1) and the highest concentration of phenolic compounds (45.32 ± 2.20 mg CAE g-1). The qualitative and quantitative analysis of GC-MS and HPLC-MS of elderflower aqueous extract allowed the identification of 46 compounds, being quercetin and chlorogenic acid representative of 86 % of the total of phenolic compounds identified in hydrophilic fraction, and naringenin (27.16 %), the major compound in lipophilic fraction. The epigenetic activity of elderflower aqueous extract on demethylation of MLH1 was tested in combination with 5-fluorouracil (5-FU) in colorectal cancer cells (RKO), using 5-azacytidine (5-azaC) as a positive control. The results suggest that the combination of elderflower extract with 5-FU did not result in a synergetic effect, which indicates that elderflower extract did not have an influence on MLH1 demethylation. Even though, the elderflower extract has several molecules with antioxidant potential, the extract did not exhibit protection or induction of repair of DNA damage after exposure to oxidative stress (H2O2). The antimicrobial activity of elderflower extract was evaluated, and it was verified that gram-positive bacteria were the most susceptible to the presence of this extract, namely, Staphylococcus aureus clinically isolated and Staphylococcus epidermidis. In conclusion, it was verified that S. nigra extract does not have the ability to modulate epigenetic activity and stimulate DNA protection/repair against oxidative stress. Although, this extract exhibits antimicrobial activity, particularly on gram-positive bacteria

La historia de las matemáticas en los cursos de educación básica en Portugal: una reflexión para la formación del profesorado

La Historia de las Matemáticas (HM) es una herramienta que puede ser muy útil en un contexto educativo. Sin embargo, la HM es un cuerpo de saber muy extenso y es necesario reflexionar cual HM debe ser enseñada en la formación inicial de los profesores en los primeros años de escolaridad. En este artículo hacemos esta reflexión tratando de justificar qué contenidos HM son realmente esenciales para los profesores y para sus futuras prácticas profesionales. En nuestra opinión, los contenidos de HM deben centrarse en los temas: sistemas de numeración de diversos pueblos, diferentes algoritmos para realizar operaciones aritméticas y resolver ecuaciones, tópicos de la geometría, así como el conocimiento de varios puntos de HM local/nacional. También damos una breve descripción de lo que son los cursos de Educación Básica en Portugal, prestando especial atención a las matemáticas que se enseñaban en estos cursos. Por otro lado, también presentamos varias referencias a estudios internacionales donde se atestigua la importancia de usar HM en el aula

The effect of Sc additions on the microstructure and age hardening behaviour of as cast Al–Sc alloys

The grain refinement effect and the ageing behaviour of Al–0.5 wt.% Sc, Al–0.7 wt.% Sc, and Al–1 wt.% Sc alloys are studied on the basis of optic microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) observations and hardness measurements. In Al–Sc alloys the higher grain refinement is observed for Sc contents greater than 0.5 wt.% accompanied by a notorious morphology modification, from coarse columnar grains to a fine perfect equiaxed structure. The as cast structures are characterized by a rich supersaturated solid solution in Sc, that promotes a great age hardening response at 250 C and 300 C. The age hardening curves also demonstrate a low overageing kinetics for all the alloys. Although the higher Sc content in solid solution for the alloys with 0.7 and 1 wt.% Sc, the age hardening response of all the Al–Sc alloys remains similar. The direct age hardening response of the as cast Al–0.5 wt.% Sc is shown to be greater than the solutionised and age hardened alloy.Fundação para a Ciência e Tecnologia (FCT