Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

Studies regarding the radiobiological effects of low dose radiation, microbeam irradiation services have been developed in the world and today laser acceleration of protons and heavy ions may be used in radiation therapy. The application of different facilities is essential for studying bystander effects and relating signalling phenomena in different cells or tissues. In particular the use of ion beams results advantageous in cancer radiotherapy compared to more commonly used X-rays, since the ability of ions in delivering lethal amount of doses into the target tumour avoiding or limiting damage to the contiguous healthy tissues. At the INFN-LNS in Catania, a multidisciplinary radiobiology group is strategically structured aimed to develop radiobiological research, finalised to therapeutic applications, compatible with the use of high dose laser-driven ion beams. The characteristic non-continuous dose rates with several orders of magnitude of laser-driven ion beams makes this facility very interesting in the cellular systems' response to ultra-high dose rates with non-conventional pulse time intervals cellular studies. Our group have projected to examine the effect of high dose laser-driven ion beams on two cellular types: foetal fibroblasts (normal control cells) and DU145 (prostate cancer cells), studying the modulation of some different bio-molecular parameters, in particular cell proliferation and viability, DNA damage, redox cellular status, morphological alterations of both the cytoskeleton components and some cell organelles and the possible presence of apoptotic or necrotic cell death. Our group performed preliminary experiments with high energy (60 MeV), dose rate of 10 Gy/min, doses of 1, 2, 3 Gy and LET 1 keV/µm on human foetal fibroblasts (control cells). We observed that cell viability was not influenced by the characteristics of the beam, the irradiation conditions or the analysis time. Conversely, DNA damage was present at time 0, immediately following irradiation in a dose-dependent manner. The analysis of repair capability showed that the cells irradiated with 1 and 2 Gy almost completely recovered from the damage, but not, however, 3 Gy treated cells in which DNA damage was not recovered. In addition, the results indicate the importance of the use of an appropriate control in radiobiological in vitro analysis.

Laser-ion accelerators: State-of-the-art and scaling laws

A significant amount of experimental work has been devoted over the last decade to the development and optimization of proton acceleration based on the so-called Target Normal Sheath acceleration mechanism. Several studies have been dedicated to the determination of scaling laws for the maximum energy of the protons as a function of the parameters of the irradiating pulses, studies based on experimental results and on models of the acceleration process. We briefly summarize the state of the art in this area, and review some of the scaling studies presented in the literature. We also discuss some recent results, and projected scalings, related to a different acceleration mechanism for ions, based on the Radiation Pressure of an ultraintense laser pulse.

First results on cell irradiation with laser-driven protons on the TARANIS system

The ultra short duration of laser-driven multi-MeV ion bursts offers the possibility of radiobiological studies at extremely high dose rates. Employing the TARANIS Terawatt laser at Queen's University, the effect of proton irradiation at MeV-range energies on live cells has been investigated at dose rates exceeding 10 Gy/s as a single exposure. A clonogenic assay showed consistent lethal effects on V-79 live, cells, which, even at these dose rates, appear to be in line with previously published results employing conventional sources. A Relative Biological Effectiveness (RBE) of 1.4±0.2 at 10% survival is estimated from a comparison with a 225 kVp X-ray source.

Viscosity Control for Extrusion Processes Using Recycled Polymers

The aim of this paper is to develop a new extruder control system for recycled materials which has ability to automatically maintain constant a polymer melt viscosity of mixed recycled polymers during extrusion, regardless of variations in the Melt Flow Index (MFI) of recycled mixed grade high density polyethylene (HDPE) feedstock. A closed-loop controller is developed to automatically regulate screw speed and barrel temperature profile to achieve constant viscosity and enable consistent processing of variable grade recycled HDPE materials. The experimental results of real time viscosity measurement and control using a 38mm single screw extruder with different recycled HDPEs with widely different MFIs are reported in this work

Pedro José da Fonseca e a sua obra lexicográfica

Este trabalho tem por objecto de estudo a obra de Pedro José da Fonseca, precipuamente a obra lexicográfica - Pawum Lexicon (1762), Diccionario Portuguez, e Latino (1771), Diccionario abbreviado da fabula (1779) e o Diccionario da Lingoa Portugueza (1 793). Necessidade premente num contexto de remodelação de todo o panorama do ensino em Portugal e de modificação das estruturas e hábitos da sociedade portuguesa, a composição destas obras iria corresponder ao consumo escolar e às solicitações da prática pedagógica almejada pela reforma pombalina. No plano geral da descrição crítica destes dicionários, atribui-se especial relevância, no cotejamento com as fontes, ao aperfeiçoamento da técnica lexicográfica. Propõe-se: o esboço da biografia do autor e um breve enquadramento históricocultural da 2" metade do século XVIII; o estudo da obra literária de Pedro da Fonseca, examinando o seu pensamento linguístico; análise da técnica de composição dicionan'stica a nível macro e microestrutural e, por fim, uma reflexão em torno do "corpus" lexical português nos dicionários de Fonseca.

Validação do método de análise de espectrofotómetria de absorção atómica/emissão de chama para determinação de minerais na fermentação de medronho (Arbustus unedo L.)

Dissertação mest., Qualidade em análises, Universidade do Algarve, 2006

Avaliação do potencial da Salicornia ramosissima para saladas frescas ou em pó (sal verde)

Dissertação de mest., Tecnologia dos Alimentos , Instituto Superior de Engenharia, Univ. do Algarve, 2013

Contributos para o estudo da pintura mural na arquitectura palatina lisboeta entre o tardo-barroco e o neoclassicismo, 1775-C. 1820

Tese de mestrado, Arte, Património e Teoria do Restauro, Universidade de Lisboa, Faculdade de Letras, 2011

Europa : paisagem e pensamento : um excurso sobre Teixeira de Pascoaes, Friedrich Hölderlin, José Marinho e Martin Heidegger

Tese de doutoramento, Filosofia (Filosofia em Portugal), Universidade de Lisboa, Faculdade de Letras, 2014

Poetry and feminine crafts in the letters of the young Marquise of Alorna (1750-1839)

abstract : Taking as a starting point the association between embroidery and language conveyed by the Greek myth of Filomela and Procne, this article examines the relationship between social status and ornaments like embroidery and lace. In order to illustrate this relationship an example is selected form the letters exchanged between the Marquise of Alorna and her Father where a connection is established between the production of these 'feminine' crafts, women's culture and womens writing, in the XVIIIth Century

Cours de construction. 3, Traité des fondations, mortiers, maçonneries / par G. Oslet & J. Chaix,...

Collection : Encyclopédie théorique et pratique des connaissances civiles et militaires ; partie 1, livre 6