In vitro studies of gum arabic-coated magnetic nanoparticles with mammalian cell cultures

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Biotecnologia

An interdisciplinary approach to the study of colour in portuguese manuscript illuminations

Dissertação apresentada para obtenção do Grau de Doutor em Conservação e Restauro, especialidade Teoria, História e Técnicas, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Magnetic nanoparticles for biocatalysis and bioseparation

Dissertação para obtenção do Grau de Mestre em Biotecnologia

Development of a piezoelectric biosensor based on PVDF films

Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica

Old cellulose for new multifunctional networks

Dissertação para obtenção do Grau de Doutor em Ciência e Engenharia de Materiais

Some Notes on the Reception of Josquin and of Northern Idioms in Portuguese Music and Culture

Although Josquin is by far the best-represented foreign composer in Gonçalo de Baena's Arte novamente inventada pera aprender a tanger (Lisbon, 1540), his music is undeniably under-represented both in the extant sixteenth-century Portuguese manuscripts containing Franco-Flemish polyphony and in volumes imported from the Netherlands such as Coimbra MM 2 and VienNB 1783. Josquin’s reputation made him, along with Ockeghem, a symbol in Portuguese humanistic culture, but up to at least the late 1530s his name seems to have been much better known than his music. Nevertheless, possible allusions to specific works by Josquin can be found in early- and mid-sixteenth-century Portuguese polyphony. By the 1520s, the general technical and stylistic characteristics of his and the following generation of northerners had begun to permeate locally produced polyphony. This eventually replaced the late-fifteenth- and early-sixteenth-century pan-consonant and homorythmic style associated with the Aragonese and the so-called Spanish court repertory.

Spectroscopic characterization of natural dyes by their non-invasive identification on pre-Columbian codices: the Maya yellow

Mesoamerican cultures had a strong tradition of written and pictorial manuscripts, called the codices. In studies already performed it was found the use of Maya Blue, made from a mixture of indigo and a clay called palygorskite, forming an incredibly stable material where the dye is trapped inside the nanotubes of the clay, after heating. However, a bigger challenge lies in the study of the yellows used, for these civilizations might have used this clay-dye mixture to produce their yellow colorants. As a first step, it was possible to provide identification, by non-invasive methods, of two colorants (a flavonoid and a carotenoid). While the flavonoid absorbed between 368-379 nm, the carotenoid would absorb around 455 nm. A temperature study also conducted allowed to set 140ºC as the desirable temperature to heat the samples without degrading them. FT-IR, conventional Raman and SERS allowed us to understand the existence of a reaction between the dyes and the clays (palygorskite and kaolinite), however it is difficult to understand it in a molecular point of view. As a second step, five species of Mexican dyes were selected on the basis of historical sources. The Maya yellow samples were produced adapting the recipe proposed by Reyes-Valerio, supporting the yellow dyes extracted from the dried plants on the clays, with addition of water, and then heated at 140ºC. It was found that the addition of water in palygorskite would increase the pH, hence deprotonating the molecules having a clear negative effect in the color. A second recipe was developed, without the addition of water; however, it was found that the use of water based binders would still alter the color of the samples with palygorskite. In this case, kaolinite without heating yield better results as a Maya yellow hybrid. It was found that the Maya chemistry might not have been the same for all the colors. The Mesoamericans might have found that different dyes could work better to their desires if matched with different clays. It was noticeable that for a clear distinction between flavonoids and carotenoids the reflectance and emission studies suffice, but when clay is added, Raman techniques will perform better. For this reason, conventional Raman and SERS were employed in order to create a database for the Mesoamerican dyestuffs for a future identification.

Engineered MRI nanoprobes based on superparamagnetic iron oxide nanoparticles

This project aimed to engineer new T2 MRI contrast agents for cell labeling based on formulations containing monodisperse iron oxide magnetic nanoparticles (MNP) coated with natural and synthetic polymers. Monodisperse MNP capped with hydrophobic ligands were synthesized by a thermal decomposition method, and further stabilized in aqueous media with citric acid or meso-2,3-dimercaptosuccinic acid (DMSA) through a ligand exchange reaction. Hydrophilic MNP-DMSA, with optimal hydrodynamic size distribution, colloidal stability and magnetic properties, were used for further functionalization with different coating materials. A covalent coupling strategy was devised to bind the biopolymer gum Arabic (GA) onto MNPDMSA and produce an efficient contrast agent, which enhanced cellular uptake in human colorectal carcinoma cells (HCT116 cell line) compared to uncoated MNP-DMSA. A similar protocol was employed to coat MNP-DMSA with a novel biopolymer produced by a biotechnological process, the exopolysaccharide (EPS) Fucopol. Similar to MNP-DMSA-GA, MNP-DMSA-EPS improved cellular uptake in HCT116 cells compared to MNP-DMSA. However, MNP-DMSA-EPS were particularly efficient towards the neural stem/progenitor cell line ReNcell VM, for which a better iron dose-dependent MRI contrast enhancement was obtained at low iron concentrations and short incubation times. A combination of synthetic and biological coating materials was also explored in this project, to design a dynamic tumortargeting nanoprobe activated by the acidic pH of tumors. The pH-dependent affinity pair neutravidin/iminobiotin, was combined in a multilayer architecture with the synthetic polymers poy-L-lysine and poly(ethylene glycol) and yielded an efficient MRI nanoprobe with ability to distinguish cells cultured in acidic pH conditions form cells cultured in physiological pH conditions.

Owner portraits and heraldry in the "Lamoignon Hours"

Because of the distance in time and the lack of testifying documents, one should be extremely careful when labelling portraits in medieval books of hours as donor portraits or owner portraits. There are, however, manuscripts that reveal their first owner within their decorative programme, and the Lamoignon Hours (Lisbon, Gulbenkian, ms LA 237) is one of these. This article aims to discuss the iconography of the three portraits found on f.165v, f.202v and f.286v, as well as the relevance of portraiture and heraldic insignia in books of hours and the significance of such content to the original owner and to those who possessed the book afterwards.