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- Augmented Reality: An Enhancer for Higher Education Students in Math's Learning?Publication . Coimbra, MMath. Teresa; Cardoso, Teresa; Mateus, ArturIn this text, we intend to answer to the following question: is Augmented Reality an enhancer for Higher Education students in math's learning? For this purpose, we define augmented reality and present a state of the art mapped mainly by studies that focus AR in educational contexts. We also describe our research, including methodological aspects in data collection and the creation of 3D contents in AR. Then, we synthesize the analysis of some preliminary data, briefly presenting perceptions and practices of students in math's learning with AR contents. Finally, we conclude that the challenges that are nowadays put to teaching methods, acquisition and subsequent knowledge consolidation may be met, to some extent, by the application of available technologies. These, in turn, should enhance a more complete understanding of contents, leading to knowledge endogenization and also to the internalization of more sustained competencies. Among those technologies, we highlight augmented reality since it can encourage motivation, comprehension and a higher involvement with the contents to be learned. Thus, it may increase the use of information and the access to knowledge, improving digital and info-inclusion.
- Biomanufacturing for tissue engineering: Present and future trendsPublication . Bartolo, Paulo; Chua, C. K.; Almeida, Henrique de Amorim; Chou, S. M.; Lim, A. S. C.Tissue engineering, often referred to as regenerative medicine and reparative medicine, is an interdisciplinary field that necessitates the combined effort of cell biologists, engineers, material scientists, mathematicians, geneticists, and clinicians toward the development of biological substitutes that restore, maintain, or improve tissue function. It has emerged as a rapidly expanding approach to address the organ shortage problem and comprises tissue regeneration and organ substitution. Cells placed on/or within constructs is the most common strategy in tissue engineering. Successful cell seeding depends on fast attachment of cell to scaffolds, high cell survival and uniform cell distribution. The seeding time is strongly dependent on the scaffold material and architecture. Scaffolds provide an initial biochemical substrate for the novel tissue until cells can produce their own extra-cellular matrix (ECM). Thus scaffolds not only define the 3D space for the formation of new tissues, but also serve to provide tissues with appropriate functions. These scaffolds are often critical, both in vivo (within the body) or in vitro (outside the body) mimicking in vivo conditions. Additive fabrication processes represent a new group of non-conventional fabrication techniques recently introduced in the biomedical engineering field. In tissue engineering, additive fabrication processes have been used to produce scaffolds with customised external shape and predefined internal morphology, allowing good control of pore size and pore distribution. This article provides a comprehensive state-of-the-art review of the application of biomanufacturing additive processes in the field of tissue engineering. New and moving trends in biomanufacturing technologies and the concept of direct cell-printing technologies are also discussed.
- Cancellative conjugation semigroups and monoidsPublication . Garrão, A. P.; Martins-Ferreira, Nelson; Raposo, M.; Sobral, M.We show that the category of cancellative conjugation semigroups is weakly Mal’tsev and give a characterization of all admissible diagrams there. In the category of cancellative conjugation monoids we describe, for Schreier split epimorphisms with codomain B and kernel X, all morphisms h: X→ B which induce a reflexive graph, an internal category or an internal groupoid. We describe Schreier split epimorphisms in terms of external actions and consider the notions of precrossed semimodule, crossed semimodule and crossed module in the context of cancellative conjugation monoids. In this category we prove that a relative version of the so-called “Smith is Huq” condition for Schreier split epimorphisms holds as well as other relative conditions.
- EditorialPublication . Bártolo, Paulo; Chua, C. K.In this issue, we invited five winners of the ‘Best Paper Awards’ at the 4th International Conference on Advanced Research in Virtual and Rapid Prototyping, Leiria, Portugal, 6-10 October 2009, to enhance their conference papers to the standard of an international journal. One paper each from ‘Materials’ track, ‘Biomanufacturing’ track and ‘Virtual Environment & Simulation’ track and two papers from ‘Advanced Rapid Prototyping Technologies and Nanofabrication’ track.
- EditorialPublication . Bartolo, Paulo; Chua, C. K.Welcome to a brand new year of 2010! In this editorial, we bring you the latest update concerning rapid prototyping technologies,which of coursemany of you are aware, include many terminologies such as layer manufacturing and solid freeform fabrication, amongst others. The longstanding need to standardize the terminologies within the rapid prototyping andmanufacturing industry has nowbeenmetwith a new ASTMInternational standard, ASTMF2792, Terminology for Additive Manufacturing Technologies. The new document is the first approved standard under the jurisdiction of ASTM Committee F42 on Additive Manufacturing Technologies, which was formed in 2009.
- Evaluation of in vitro degradation of PCL scaffolds fabricated via BioExtrusion. Part 1: Influence of the degradation environmentPublication . Domingos, M.; Chiellini, F.; Cometa, S.; De Giglio, E.; Grillo-Fernandes, E.; Bártolo, P.; Chiellini, E.One of the most promising approaches in tissue engineering (TE) comprises the development of 3D porous scaffolds which are able to promote tissue regeneration. Biocompatible and biodegradable poly(e-caprolactone) (PCL) structures are increasingly used as temporary extra-cellular matrices for bone tissue engineering. To ensure an appropriate bone restoration over the long term, the selected material must have a degradation rate that match the in-growth of new bone. The in vivo process, by which the scaffold degrades and is resorbed transferring the load and function back to the host tissue, is complex. Consequently, an appropriate preliminary in vitro study is required. A novel extrusion-based technology called BioExtruder was used to produce PCL porous scaffolds made with layers of directionally aligned microfilaments. The in vitro degradation behaviour in both simulated body fluid (SBF) and phosphate buffer solution (PBS) were investigated over 6 months. The characterization of the degradation behaviour of the structures was performed at specific times by evaluating changes in the average molecular weight, the weight loss and its thermal properties. Morphological and surface chemical analyses were also performed using a Scanning Electron Microscopy (SEM) and an X-ray Photoelectron Spectroscopy (XPS), respectively.
- Layer manufacturing of magnesium and its alloy structures for future applicationsPublication . Ng, C. C.; Savalani, M. M.; Man, H. C.; Gibson, I.This research aims to develop a rapid layer manufacturing technique to provide magnesium bone substitute for future applications in the medical fields. Selective laser melting (SLM), which is a laser based additive layer manufacturing technique and capable of producing required geometries directly from CAD data, is selected to build magnesium structures. Magnesium has several intrinsic properties including its excellent biocompat-ibility, biodegradable, bioresorbabiltity and proper mechanical properties which would make it suitable for orthopaedic applications. This paper will discuss the status quo of this material and its future implications. A miniature SLM system was built to achieve better control of the atmospheric conditions in which the magnesium would melt. The results revealed that the SLM is a promising technique to fabricate magnesium substitute for various orthopaedic applications.
- Neural Markers of Neuropathic Pain Associated with Maladaptive Plasticity in Spinal Cord InjuryPublication . Pascoal-Faria, Paula; Yalcin, Nilufer; Fregni, FelipeObjectives: Given the potential use of neural markers for the development of novel treatments in spinal cord pain, we aimed to characterize the most effective neural markers of neuropathic pain following spinal cord injury (SCI). Methods: A systematic PubMed review was conducted, compiling studies that were published prior to April, 2014 that examined neural markers associated with neuropathic pain after SCI using electrophysiological and neuroimaging techniques. Results: We identified 6 studies: Four using electroencephalogram (EEG); 1 using magnetic resonance imaging (MRI) and FDG-PET (positron emission tomography); and 1 using MR spectroscopy. The EEG recordings suggested a reduction in alpha EEG peak frequency activity in the frontal regions of SCI patients with neuropathic pain. The MRI scans showed volume loss, primarily in the gray matter of the left dorsolateral prefrontal cortex, and by FDG-PET, hypometabolism in the medial prefrontal cortex was observed in SCI patients with neuropathic pain compared with healthy subjects. In the MR spectroscopy findings, the presence of pain was associated with changes in the prefrontal cortex and anterior cingulate cortex. Conclusions: When analyzed together, the results of these studies seem to point out to a common marker of pain in SCI characterized by decreased cortical activity in frontal areas and possibly increased subcortical activity. These results may contribute to planning further mechanistic studies as to better understand the mechanisms by which neuropathic pain is modulated in patients with SCI as well as clinical studies investigating best responders of treatment.
- A Note on the “Smith is Huq” ConditionPublication . Martins-Ferreira, Nelson; Van der Linden, TimWe show that two known conditions which arose naturally in commutator theory and in the theory of internal crossed modules coincide: every starmultiplicative graph is multiplicative if and only if every two ef fective equivalence relations commute as soon as their normalisations do. This answers a question asked by George Janelidze.
- An observation on n-permutabilityPublication . Martins-Ferreira, Nelson; Rodelo, Diana; Van der Linden, TimWe prove that in a regular category all reflexive and transitive relations are symmetric if and only if every internal category is an internal groupoid. In particular, these conditions hold when the category is n-permutable for some n.