Untitled

Funder

Organizational Unit

Publications

Composition and microstructure of Roman metallic artefacts of Southwestern Iberian Peninsula

Publication . Valério, Pedro; Voráčová, E.; Silva, R. J. C.; Araújo, Maria de Fátima; Soares, António Monge; Arruda, Ana Margarida; Pereira, Carlos

The Roman invasion introduces new alloys and metallurgical practices in Iberian Peninsula. The southwestern end of this region has many evidences of connections with the Roman World, but there are no studies about the manufacture and use of copper-based artefacts during this period. Therefore, a set of about 20 ornaments, tools and small attachments recovered at the Roman sites of Monte Molião and Cidade das Rosas was studied by na analytical approach combining micro-EDXRF, optical microscopy, SEM–EDS and Vickers microhardness testing. The artefact composition shows a good correlation with function, namely pure copper for nails and rivets, lowtin bronze (2–6 wt% Sn) for basic tools, high-tin bronze (14 wt% Sn) for fibulae and high-lead bronze (19 wt% Pb) for a decorated jug handle. The manufacture also depends on function because most artefacts were subjected to thermomechanical processing, except the ornaments that would not benefit from post-casting work. Brass and gunmetal were only present in the site with a later chronology. A metallurgy visibly ruled by economical, aesthetical and technological concerns reinforces the evidences about the total integration of Southwestern Iberian Peninsula in the Roman World, but further studies will be essential to determine the evolution of copper-based alloys in Lusitania under Roman influence.

2015-08Journal article

Restricted access

The Composition of the São Brás Copper Hoard in Relation to the Bell Beaker Metallurgy in the South-western Iberian Peninsula

Publication . Valério, Pedro; Soares, Joaquina; Araújo, Maria de Fátima; Alves, L. C.; Silva, Carlos Tavares da

A large ceramic vessel was discovered at São Brás (southern Portugal) containing a metallic hoard from the Chalcolithic/Early Bronze Age period. These weapons and tools were characterized by microanalytical techniques as being composed of copper with varying arsenic contents (2.2± 1.6 wt%) and minor amounts of lead, bismuth and iron. The collection shows a clear association between daggers and copper with a higher arsenic content, which can be explained by the high status of these silvery alloys. Finally, the compositional distribution of the hoard was compared with the metallurgy of the Bell Beaker and non–Bell Beaker communities inhabiting the south-western Iberian Peninsula.

2018Journal article

Open access

Exploring the cytotoxic activity of new phenanthroline salicylaldimine Zn(II) complexes

Publication . Matos, Cristina; Addis, Yemataw; Nunes, Patrique; Barroso, Sónia; Alho, Irina; Martins, Marta; Matos, António P.A.; Marques, Fernanda; Cavaco, Isabel; Pessoa, João; Correia, Isabel

Zinc(II) complexes bearing N-salicylideneglycinate (Sal-Gly) and 1,10-phenanthroline (phen) or phenanthroline derivatives [NN = 5-chloro-1,10-phenanthroline, 5-amine-1,10-phenanthroline (amphen), 4,7-diphenyl-1,10-phenanthroline (Bphen) and 5,6-epoxy-5,6-dihydro-1,10-phenanthroline] are synthesized. Complexes formulated as [Zn(NN)2(H2O)2]2+(NN = phen and amphen), are also prepared. The cytotoxicity of the compounds is evaluated towards a panel of human cancer cells: ovarian (A2780), breast (MCF7) and cervical (HeLa), as well as non-tumoral V79 fibroblasts. All compounds display higher cytotoxicity than cisplatin (IC50 = 22.5 ± 5.0 μM) towards ovarian cells, showing IC50values in the low micromolar range. Overall, all compounds show higher selectivity for the A2780 cells than for the non-tumoral cells and higher selectivity indexes (IC50(V79)/IC50(A2780) than cisplatin. [Zn(Sal-Gly)(NN)(H2O)] complexes induce caspase-dependent apoptosis in A2780 cells, except [Zn(Sal-Gly)(Bphen)(H2O)], one of the most cytotoxic of the series. The cellular uptake in the ovarian cells analyzed by Inductively Coupled Plasma mass spectrometry indicates different Zn distribution profiles. Transmission electronic microscopy shows mitochondria alterations and apoptotic features consistent with caspase activation; cells incubated with [Zn(Sal-Gly)(amphen)(H2O)] present additional nuclear membrane alterations in agreement with significant association with the nucleus. The increase of reactive oxygen species and lipid peroxidation forms could be related to apoptosis induction. [Zn(NN)2(H2O)2]2+complexes have high ability to bind DNA through intercalation/groove binding, and circular dichroism data suggests that the main type of species that interact with DNA is [Zn(NN)]2+. Studies varying the % of fetal bovine serum (1-15%) in cell media show that albumin binding decreases the complex activity, indicating that distinct speciation of Zn- and phen-containing species in cell media may affect the cytotoxicity.

2019Journal article

Open access

Metallurgical production from the Chalcolithic settlement of Moita da Ladra, Portugal

Publication . Pereira, Filipa; Silva, Rui J. C.; Soares, António M. Monge; Araújo, Maria F.; Cardoso, João Luís

The Chalcolithic site of Moita da Ladra, on the right bank of the River Tagus, near Vila Franca de Xira (Portugal), was mainly settled during the second half of the 3rd millennium BC. The large amount of metal artifacts and metallurgical remains recovered at the site indicates local metallurgical activities. Chemical and microstructural characterization of 62 copper-based artifacts and 8 metallic nodules from the settlement are presented. Micro-EDXRF, optical microscopy, SEM-EDS and Vickers microhardness testing were applied in this research. Elemental determinations show artifacts containing variable amounts of arsenic. Forty-five percent of the artifacts have an arsenic content at impurity level (As < 2 wt.%), while the remaining items range from 2.0 wt.% to 5.4 wt.% As. Microstructural analysis shows that artifacts were shaped by hammering and annealing cycles, being 33% of the artifacts finished by cold working. Metallic nodules were produced by smelting operations, and are chemically consistent with the analysed artifact collection. Results are compared with those obtained by similar researches carried out on important contemporary materials from the same geographical area (Portuguese Estremadura) and other Iberian regions (Southern Portugal and Western Andalusia).

2016Journal article

Restricted access

Radiolabeled block copolymer micelles for image-guided drug delivery

Publication . Ribeiro, Elisabete; Alho, Irina; Marques, Fernanda; Gano, Lurdes; Correia, Isabel; Correia, João D. G.; Casimiro, Sandra; Costa, Luis; Santos, Isabel Cordeiro; Fernandes, Célia

We aimed at exploring block copolymer micelles (BCMs) for the simultaneous delivery of radiation/chemotherapy to cancer cells. To achieve that goal, we have prepared and characterized a novel type of docetaxel (DTX) loaded and non-loaded BCMs. The micelles were decorated with pyrazolyl-diamine chelating units to stabilize the matched pair 99mTc/Re for image-guided delivery of therapeutic drugs. The in vitro studies have shown that DTX release is pH-dependent increasing at lower pH values. Anti-proliferative studies in different cancer cell lines showed that DTX-loaded BCMs present relevant anti-proliferative activity. In comparison to free DTX, the loaded-micelles exhibited higher anti-proliferative activity for the same DTX concentration, which mean that a similar therapeutic outcome may be achieved with reduced side effects. The pyrazolyl-diamine-functionalized micelles were labeled with fac-[99mTc(CO)3(H2O)3]+ in high radiochemical yield and purity. The radiolabeled micelles are stable in phosphate buffer and in cell culture media. Cellular uptake studies in different cancer cell lines indicate a cell type and time-dependent uptake, in agreement with the anti-proliferative activity. Early biodistribution studies in healthy BALB/c mice has shown prolonged circulation lifetime in the bloodstream and relevant in vivo stability, important features when considering an effective DTX delivery system and image-guided delivery agent for cancer theranostics.

2016Journal article

Restricted access