Modifying fish gelatin electrospun membranes for biomedical applications: cross- linking and swelling behavior

Development of suitable membranes is a fundamental requisite for tissue and biomedical engineering applications. This work presents fish gelatin random and aligned electrospun membranes cross-linked with glutaraldehyde (GA). It was observed that the fiber average diameter and the morphology is not influenced by the GA exposure time and presents fibers with an average diameter around 250 nm. Moreover, when the gelatin mats are immersed in a phosphate buffered saline solution (PBS), they can retain as much as 12 times its initial weight of solution almost instantaneously, but the material microstructure of the fiber mats changes from the characteristic fibrous to an almost spherical porous structure. Cross-linked gelatin electrospun fiber mats and films showed a water vapor permeability of 1.37 ± 0.02 and 0.13 ± 0.10 (g.mm)/(m2.h.kPa), respectively. Finally, the processing technique and cross-linking process does not inhibit MC-3T3-E1 cell adhesion. Preliminary cell culture results showed good cell adhesion and proliferation in the cross-linked random and aligned gelatin fiber mats.

Silicon in plant disease control

All essential nutrients can affect the incidence and severity of plant diseases. Although silicon (Si) is not considered as an essential nutrient for plants, it stands out for its potential to decrease disease intensity in many crops. The mechanism of Si action in plant resistance is still unclear. Si deposition in plant cell walls raised the hypothesis of a possible physical barrier to pathogen penetration. However, the increased activity of phenolic compounds, polyphenol oxidases and peroxidases in plants treated with Si demonstrates the involvement of this element in the induction of plant defense responses. The studies examined in this review address the role of Si in disease control and the possible mechanisms involved in the mode of Si action in disease resistance in plants.

ITO/SiOx/Si optical sensor with internal gain

A visible/near-infrared optical sensor based on an ITO/SiOx/n-Si structure with internal gain is presented. This surface-barrier structure was fabricated by a low-temperature processing technique. The interface properties and carder transport were investigated from dark current-voltage and capacitance-voltage characteristics. Examination of the multiplication properties was performed under different light excitation and reverse bias conditions. The spectral and pulse response characteristics are analysed. The current amplification mechanism is interpreted by the control of electron current by the space charge of photogenerated holes near the SiOx/Si interface. The optical sensor output characteristics and some possible device applications are presented.

Sensor element for a metal-insulator-semiconductor camera system (MISCam)

We discuss the operation of a new type of optical sensor (MISCam) based on a metal-insulator-semiconductor (MIS) structure. The operation principle relies on light-induced changes of the band bending and barrier height at the interface between semiconductor and insulator. An image is obtained from the quenching of the ac signal in analogy to the principle of the laser-scanned photodiode (LSP). Lateral resolution depends on the semiconductor material chosen. We have characterised the MIS structures by C-V, I-V, and spectral response measurements testing different types of insulators like a-Si3N4, SiO2, and AlN. The presence of slow interface charges allows for image memory. Colour sensors can be realised by controlling sign and magnitude of the electric fields in the base and the interface region.

Structural and Microanalytical Studies of CrO2 Thin Films on c-Sapphire by High Resolution Electron Microscopy Methods

Chromium dioxide (CrO2) has been extensively used in the magnetic recording industry. However, it is its ferromagnetic half-metallic nature that has more recently attracted much attention, primarily for the development of spintronic devices. CrO2 is the only stoichiometric binary oxide theoretically predicted to be fully spin polarized at the Fermi level. It presents a Curie temperature of ∼ 396 K, i.e. well above room temperature, and a magnetic moment of 2 mB per formula unit. However an antiferromagnetic native insulating layer of Cr2O3 is always present on the CrO2 surface which enhances the CrO2 magnetoresistance and might be used as a barrier in magnetic tunnel junctions.

Desvio de posicionamento em radioterapia para patologias de cabeça e pescoço e próstata: revisão de literatura

Introdução – Numa era em que os tratamentos de Radioterapia Externa (RTE) exigem cada vez mais precisão, a utilização de imagem médica permitirá medir, quantificar e avaliar o impacto do erro provocado pela execução do tratamento ou pelos movimentos dos órgãos. Objetivo – Analisar os dados existentes na literatura acerca de desvios de posicionamento (DP) em patologias de cabeça e pescoço (CP) e próstata, medidos com Cone Beam Computed Tomography (CBCT) ou Electronic Portal Image Device (EPID). Metodologia – Para esta revisão da literatura foram pesquisados artigos recorrendo às bases de dados MEDLINE/PubMed e b-on. Foram incluídos artigos que reportassem DP em patologias CP e próstata medidos através de CBCT e EPID. Seguidamente foram aplicados critérios de validação, que permitiram a seleção dos estudos. Resultados – Após a análise de 35 artigos foram incluídos 13 estudos e validados 9 estudos. Para tumores CP, a média (μ) dos DP encontra-se entre 0,0 e 1,2mm, com um desvio padrão (σ) máximo de 1,3mm. Para patologias de próstata observa-se μDP compreendido entre 0,0 e 7,1mm, com σ máximo de 7,5mm. Discussão/Conclusão – Os DP em patologias CP são atribuídos, maioritariamente, aos efeitos secundários da RTE, como mucosite e dor, que afetam a deglutição e conduzem ao emagrecimento, contribuindo para a instabilidade da posição do doente durante o tratamento, aumentando as incertezas de posicionamento. Os movimentos da próstata devem-se principalmente às variações de preenchimento vesical, retal e gás intestinal. O desconhecimento dos DP afeta negativamente a precisão da RTE. É importante detetá-los e quantificá-los para calcular margens adequadas e a magnitude dos erros, aumentando a precisão da administração de RTE, incluindo o aumento da segurança do doente. - ABSTRACT - Background and Purpose – In an era where precision is an increasing necessity in external radiotherapy (RT), modern medical imaging techniques provide means for measuring, quantifying and evaluating the impact of treatment execution and movement error. The aim of this paper is to review the current literature on the quantification of setup deviations (SD) in patients with head and neck (H&N) or prostate tumors, using Cone Beam Computed Tomography (CBCT) or Electronic Portal Image Device (EPID). Methods – According to the study protocol, MEDLINE/PubMed and b-on databases were searched for trials, which were analyzed using selection criteria based on the quality of the articles. Results – After assessment of 35 papers, 13 studies were included in this analysis and nine were authenticated (6 for prostate and 3 for H&N tumors). The SD in the treatment of H&N cancer patients is in the interval of 0.1 to 1.2mm, whereas in prostate cancer this interval is 0.0 to 7.1mm. Discussion – The reproducibility of patient positioning is the biggest barrier for higher precision in RT, which is affected by geometrical uncertainty, positioning errors and inter or intra-fraction organ movement. There are random and systematic errors associated to patient positioning, introduced since the treatment planning phase or through physiological organ movement. Conclusion – The H&N SD are mostly assigned to the Radiotherapy adverse effects, like mucositis and pain, which affect swallowing and decrease secretions, contributing for the instability of patient positioning during RT treatment and increasing positioning uncertainties. Prostate motion is mainly related to the variation in bladder and rectal filling. Ignoring SD affects negatively the accuracy of RT. Therefore, detection and quantification of SD is crucial in order to calculate appropriate margins, the magnitude of error and to improve accuracy in RTE and patient safety.

Chitosan-alginate microparticulate delivery system for an alternative route of administration of BCG vaccine

Immunisation against M. tuberculosis with current available BCG vaccine lacks efficacy in preventing adult pulmonary tuberculosis. Targeting nasal mucosa is an attractive option for a more effective immunization. The delivery of BCG via the intranasal route involves overcoming barriers such as crossing the physical barrier imposed by the mucus layer and ciliar remotion, cellular uptake and intracellular trafficking by antigen presenting cells. Due to its biodegradable, immunogenic and mucoadhesive properties, chitosan particulate delivery systems can act both as vaccine carrier and adjuvant, improving the elicited immune response. In this study, different combinations of Chitosan/Alginate/TPP microparticles with BCG were produced as vaccine systems. The developed microparticle system successfully modulates BCG surface physicochemical properties and promotes effective intracellular uptake by human macrophage cell lines Preliminary immune responses were evaluated after s.c. and intranasal immunisation of BALB/c mice. BCG vaccination successfully stimulated the segregation of IgG2a and IgG1, where intranasal immunisation with chitosan/alginate particulate system efficiently elicited a more equilibrated cellular/humoral immune response.

Os departamentos curriculares e as práticas de colaboração docente

Dissertação de Mestrado, Educação (Administração e Organização Escolar), 7 de Fevereiro de 2014, Universidade dos Açores.

Analysis of functionally graded sandwich plate structures with piezoelectric skins, using B-spline finite strip method

Functionally graded materials are composite materials wherein the composition of the constituent phases can vary in a smooth continuous way with a gradation which is function of its spatial coordinates. This characteristic proves to be an important issue as it can minimize abrupt variations of the material properties which are usually responsible for localized high values of stresses, and simultaneously providing an effective thermal barrier in specific applications. In the present work, it is studied the static and free vibration behaviour of functionally graded sandwich plate type structures, using B-spline finite strip element models based on different shear deformation theories. The effective properties of functionally graded materials are estimated according to Mori-Tanaka homogenization scheme. These sandwich structures can also consider the existence of outer skins of piezoelectric materials, thus achieving them adaptive characteristics. The performance of the models, are illustrated through a set of test cases. (C) 2012 Elsevier Ltd. All rights reserved.

Iniciação à ciência através da metodologia de trabalho de projeto – um contexto privilegiado para o desenvolvimento da linguagem no pré-escolar

A aprendizagem da Ciência tem-se revelado difícil, nos diferentes níveis de ensino, como tem mostrado a inúmera investigação educacional que tem vindo a ser realizada desde a década de sessenta do séc. XX. A Linguagem científica constitui uma (primeira) barreira para os aprendentes de Ciência. As dificuldades são de natureza diversa. No presente artigo procuraremos mostrar como uma iniciação à Ciência, através da Metodologia de Trabalho de Projeto, pode constituir uma metodologia privilegiada por permitir não só a aquisição de significado para termos técnicos, como também a atribuição de novos significados a palavras da linguagem corrente e a utilização de conectores lógicos. Recorreremos a exemplos recolhidos de situações de estágios profissionais que acompanhámos.

Investigação em comunidades dominadas por macroalgas: situação actual, aplicações e desenvolvimentos futuros

Conhecer o Mar dos Açores. Fórum Científico de Apoio à Decisão, Horta, 19 de Janeiro de 2011.

Diversity of the Laurencia complex (Ceramiales, Rhodophyta) in Lusitanian Macronesia

10th International Phycological Congress, Orlando, Florida, USA, 4-10 de agosto 2013.

New mitochondrial and nuclear evidences support recent demographic expansion and an atypical phylogeographic pattern in the Spittlebug Philaenus spumarius (Hemiptera, Aphrophoridae)

Copyright: © 2014 Rodrigues et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Transvase : quando a ficção invade a realidade

ABSTRACT: Adopting the concept of metalepsis, as explained by Gérard Genette, I intend to tackle the miscegenation of ontological worlds as practiced in metacinematic films dealing either with the creator or the spectator and made famous with Woody Allen’s film The Purple Rose of Cairo (1985, EUA). Assuming the existence of two adjoining fictional universes, one of them intrafilmically projected onto a screen and the other positioned in front of it so as to create or observe the other, one realizes that, in fact, they both communicate in a more intense way. That is, they both can cross the barrier that separates them and function, literally, as communicating vessels thrusting themselves onto the other side of fiction. The use of this screen passage technique – which I call ‘spilling narrative’ – although it takes place inside the film, at an intradiegetic level, cannot be considered a simple comic effect. In actuality, it is a very serious affair, denoting the authorial intervention as a reflexive practice of écriture by means of a mise en abyme, according to Lucien Dällenbach. Therefore, the fictional spilling over of worlds which totally blends together both sides of the twice artificial universe of the fabula, represents the emotional and intellectual involvement of the creator with his/her creation and of the spectator with the world watched. Both illustrate the desire of fusion inherent in the acts of creation and reception. My approach will be based on Gabriele Salvatores’ Happy Family (2010) and Wojciech Marczewski’s Escape from the ‘Liberty’ Cinema (1990).

Functional biogeography of oceanic islands and the scaling of functional diversity in the Azores

Analyses of species-diversity patterns of remote islands have been crucial to the development of biogeographic theory, yet little is known about corresponding patterns in functional traits on islands and how, for example, they may be affected by the introduction of exotic species. We collated trait data for spiders and beetles and used a functional diversity index (FRic) to test for nonrandomness in the contribution of endemic, other native (also combined as indigenous), and exotic species to functional-trait space across the nine islands of the Azores. In general, for both taxa and for each distributional category, functional diversity increases with species richness, which, in turn scales with island area. Null simulations support the hypothesis that each distributional group contributes to functional diversity in proportion to their species richness. Exotic spiders have added novel trait space to a greater degree than have exotic beetles, likely indicating greater impact of the reduction of immigration filters and/or differential historical losses of indigenous species. Analyses of species occurring in native-forest remnants provide limited indications of the operation of habitat filtering of exotics for three islands, but only for beetles. Although the general linear (not saturating) pattern of trait-space increase with richness of exotics suggests an ongoing process of functional enrichment and accommodation, further work is urgently needed to determine how estimates of extinction debt of indigenous species should be adjusted in the light of these findings.