The innovation of the new psychoactive substances (NPS) market requires the rapid identification of new substances that can be a risk to public health, in order to reduce the damage from their use. Twelve seized products suspected to contain illicit substances were analyzed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), gas chromatography coupled to mass spectrometry (GC-MS), and nuclear magnetic resonance spectroscopy (NMR). Synthetic cathinones (SCat) were found in all products, either as a single component or in mixtures. Infrared spectra of all products were consistent with the molecular structure of SCat, showing an intense absorption band at 1700-1674 cm-1, corresponding to the carbonyl stretching, a medium/strong peak at 1605-1580 cm-1, indicating stretching vibrations in the aromatic ring (C=C) and bands with relative low intensity at frequencies near 2700-2400 cm-1, corresponding to an amine salt. It was possible to identify a total of eight cathinone derivatives by GC-MS and NMR analysis: 4'-methyl-α-pyrrolidinohexanophenone (MPHP), α-pyrrolidinohexanophenone (α-PHP), 3-fluoromethcathinone (3-FMC), methedrone, methylone, buphedrone, N-ethylcathinone, and pentedrone. Among the adulterants found in these samples, caffeine was the most frequently detected substance, followed by ethylphenidate. These results highlight the prevalence of SCat in seized materials of the Portuguese market. Reference standards are usually required for confirmation, but when reference materials are not available, the combination of complementary techniques is fundamental for a rapid and an unequivocal identification of such substances.

(Excerpt of the Introduction) Breast cancer is one of the most common types, with higher incidence in females, and it ranks as the second leading cause of cancer-related deaths in Portugal. Some of the most common symptoms include the appearance of new breast nodules, bone, chest or abdominal pain, shortness of breath, and headaches. The incidence of this disease has a positive correlation with age and is directly related to mammographic density. This relationship arises from the combined effects of cell proliferation in response to mitogens and generic data caused by mutagens.

A decentralized energy system requires photovoltaic solutions to meet new aesthetic paradigms, such as lightness, flexibility, and new form factors. Notwithstanding, the materials shortage in the Green Transition is a concern gaining momentum due to their foreseen continuous demand. A fruitful strategy to shrink the absorber thickness, meeting aesthetic and shortage materials consumption targets, arises from interface passivation. However, a deep understanding of passivated systems is required to close the efficiency gap between ultra-thin and thin film devices, and to mono-Si. Herein, a (Ag,Cu)(In,Ga)Se2 ultra-thin solar cell, with 92% passivated rear interface area, is compared with a conventional nonpassivated counterpart. A thin MoSe2 layer, for a quasi-ohmic contact, is present in the two architectures at the contacts, despite the passivated device narrow line scheme. The devices present striking differences in charge carrier dynamics. Electrical and optoelectronic analysis combined with SCAPS modelling suggest a lower recombination rate for the passivated device, through a reduction on the rear surface recombination velocity and overall defects, comparing with the reference solar cell. The new architecture allows for a 2% efficiency improvement on a 640 nm ultra-thin device, from 11% to 13%, stemming from an open circuit voltage increase of 108 mV.

Despite the evolution of targeted therapies in oncology, some challenges such as screening and early diagnosis of cancer-related biomarkers still remain. The analysis of the Human Epidermal growth factor Receptor 2 (HER2) in biological fluids provides essential information for effective treatments. In this work we report the development of an electrochemical immunomagnetic bioassay for the analysis of the extracellular domain of HER2 (HER2-ECD) in human serum and cancer cells. Biomodified carboxylic acid functionalized magnetic beads (COOH-MBs) were used as the capture probe and an antibody labelled with alkaline phosphatase (AP) as the signalling probe. In the presence of HER2-ECD a sandwich complex was formed on the MBs, which were magnetically attracted to the surface of a screen-printed carbon electrode (SPCE). After the addition of 3-indoxyl phosphate and silver ions, used as the enzymatic substrate, the immunological interaction was detected by linear sweep voltammetry. Two linear concentration ranges were established: one between 5.0 and 50 ng/mL and another between 50 and 100 ng/mL. The developed assay provided a clinically useful detection limit (2.8 ng/mL) and has an adequate precision (Vx0 < 5%). The assay provided accurate results and was selective towards the target biomarker. Additionally, CTCs were analysed in human serum and a detection limit of 3 cells/mL was achieved for the HER+ breast cancer cell line SK-BR-3.

Two activated carbons (AC) resulting from CO2 activation of Maize Cob Waste (MCW) were investigated as adsorbent materials for biogas upgrading to bio-methane applying a biorefinery concept. The porous carbons were originated from different times of activation and the one resulting from 3 h with CO2 (MCW(PA)3 h) showed better textural properties, higher working capacity, and selectivity towards CO2 than the carbon resulting from 2 h of activation (MCW(PA)2 h), making it the best candidate for biogas purification. The adsorption equilibrium measurements of CO2 and CH4 on MCW(PA)3 h carbon showed that the Sips isotherm model, as well as the Adsorption Potential Theory (APT), can be confidently employed to accurately correlate the adsorption equilibrium data of the adsorbates employed. In the range of the partial pressures typical for biogas upgrading units, MCW(PA)3 h showed higher CO2 uptakes than the ones reported for coal-based commercial ACs and similar uptakes to the ones reported for bio-based ACs. Moreover, the axial dispersed plug-flow and Linear Driving Force (LDF) approximation for lumped solid-diffusion mass transfer model used for the prediction of the dynamic behaviour of the adsorbate-adsorbent system, provided a good agreement with the experimental results, demonstrating its applicability to the studied system. This work represents the basis of future modelling works of a Pressure Swing Adsorption (PSA) cycle based on the use of MCW(PA)3 h as adsorbent material and demonstrates the high potential of this novel material to be applied in biogas upgrading processes

The incidence of breast cancer has been increasing over the years. To control and monitor this disease several tumor biomarkers have been proposed for early diagnosis, patient follow-up and/or treatment guidance. The only serum breast cancer biomarker in current use is the cancer antigen 15-3 (CA 15-3). In this work a molecularly imprinted polymer (MIP)-based electrochemical (voltammetric) sensor to monitor breast cancer was developed, based on direct surface imprinting of CA 15-3 on a screen-printed gold electrode (Au-SPE). The imprinting was performed in two steps: (1) adsorption of CA 15-3 on the surface of the Au-SPE and (2) electropolymerization of 2-aminophenol around the adsorbed protein. After extraction of the imprinted protein voltammetric analysis was conducted using hexacyanoferrate(II/III) as redox probe, measuring the signals before and after protein binding. The sensor was characterized by voltammetric techniques and electrochemical impedance spectroscopy, and the analytical responses of imprinted and non-imprinted polymer sensors were studied. A linear relationship between the peak current intensity of the redox probe and the logarithm of CA 15-3 concentration was established between 5 and 50 U mL−1, achieving a limit of detection of 1.5 U mL−1. The prepared MIP-sensor provides fast (15 min) analysis and is cheap, easy to prepare, disposable and could easily be integrated in small portable point-of care devices.

Streptococcus dysgalactiae subsp. dysgalactiae (SDSD) is an important agent of bovine mastitis. This infection causes an inflammatory reaction in udder tissue, being the most important disease-causing significant impact on the dairy industry. Therefore, it leads to an increase in dairy farming to meet commercial demands. As a result, there is a major impact on both the dairy industry and the environment including global warming. Recurrent mastitis is often attributed to the development of bacterial biofilms, which promote survival of sessile cells in hostile environments, and resistance to the immune system defense and antimicrobial therapy. Recently, we described the in vitro biofilm development on abiotic surfaces by bovine SDSD. In that work we integrated microbiology, imaging, and computational methods to evaluate the biofilm production capability of SDSD isolates on abiotic surfaces. Additionally, we reported that bovine SDSD can adhere and internalize human cells, including human epidermal keratinocyte (HEK) cells. We showed that the adherence and internalization rates of bovine SDSD isolates in HEK cells are higher than those of a SDSD DB49998-05 isolated from humans. In vivo, bovine SDSD can cause invasive infections leading to zebrafish morbidity and mortality. In the present work, we investigated for the first time the capability of bovine SDSD to develop biofilm in vivo using a murine animal model and ex-vivo on human HEK cells. Bovine SDSD isolates were selected based on their ability to form weak, moderate, or strong biofilms on glass surfaces. Our results showed that SDSD isolates displayed an increased ability to form biofilms on the surface of catheters implanted in mice when compared to in vitro biofilm formation on abiotic surface. A greater ability to form biofilm in vitro after animal passage was observed for the VSD45 isolate, but not for the other isolates tested. Besides that, in vitro scanning electron microscopy demonstrated that SDSD biofilm development was visible after 4 hours of SDSD adhesion to HEK cells. Cell viability tests showed an important reduction in the number of HEK cells after the formation of SDSD biofilms. In this study, the expression of genes encoding BrpA-like (biofilm regulatory protein), FbpA (fibronectin-binding protein A), HtrA (serine protease), and SagA (streptolysin S precursor) was higher for biofilm grown in vivo than in vitro, suggesting a potential role for these virulence determinants in the biofilm-development, host colonization, and SDSD infections. Taken together, these results demonstrate that SDSD can develop biofilms in vivo and on the surface of HEK cells causing important cellular damages. As SDSD infections are considered zoonotic diseases, our data contribute to a better understanding of the role of biofilm accumulation during SDSD colonization and pathogenesis not only in bovine mastitis, but they also shed some lights on the mechanisms of prosthesis-associated infection and cellulitis caused by SDSD in humans, as well.

In this work, the activity of horseradish peroxidase (HRP) in betaine-based natural deep eutectic systems (NADESs) was measured and studied by molecular simulations. Focus was laid on enzymatic activity in the NADESs under thermal stress as well as under the influence of water. Furthermore, the structure of HRP under these different conditions was measured by circular dichroism (CD). As a result, HRP remains enzymatically active in all NADESs upon incubation for 24 h at 37 °C and 60 °C and after 4 h at 80 °C, especially when incubated in a NADES composed of betaine, trehalose, glycerol, and water, in a molar ratio of 2 : 1 : 3 : 5. The CD studies have shown that high activity is obtained in the systems that promoted higher α-helix contents. The molecular simulations showed that using a NADES instead of buffer solvent reduces HRP flexibility, and we found that enzymatic activity correlates with Gibbs energy of solvation of HRP. Finally, hydrophobic hydration interactions govern the stabilization mechanism of the HRP folded state as shown by a drastic enzymatic activity drop upon 5 wt% water addition using a betaine: glycerol NADES as solvent.

The most common type of cancer treatment, chemotherapy, often fails due to the acquisition of resistance. It is therefore of the utmost importance to better understand the cellular mechanisms of resistance, while developing new strategies to tackle drug resistance. Nanomedicine promises to develop new tools for diagnosing and treating of diseases, improving human health. This thesis explored five main strategies to overcome drug resistance in cancer cells: i) new anti-cancer compounds, ii) nanovectorisation and targeting of compounds, iii) gold nanoparticles (AuNP) for hyperthermia and combination with chemotherapy iv) AuNP assisted angiogenesis arrest with laser ablation and chemotherapy v) AuNP mediated gene silencing of efflux pumps. We started by characterizing the mechanism of action of a new anti-tumour compound (ZnD), that was able to reduce the viability of a colon cancer cell line (HCT116 DR) resistant to doxorubicin (DOX), a first-line chemotherapeutic. We vectorized our compound with AuNP, resulting in increased toxicity to HCT116 DR mouse xenografts. Taking advantage of the photothermal properties of AuNP, we combined chemotherapy with photo hyperthermia by irradiating AuNP with a green laser. Hyperthermia was especially effective against HCT116 DR. Since angiogenesis is a milestone in cancer development, we aimed to prevent it, using an anti-angiogenic peptide vectorized with AuNP and laser irradiation, resulting in a vascularization reduction of 91% in vivo. We have observed that ABCB1 efflux pump was the major cause of resistance of DOX resist cell line, therefore we silenced its mRNA with an anti-sense oligonucleotide AuNP. Our results showed that although the silencing was effective, cells did not return to a sensitive phenotype, requiring further experiments. Altogether this thesis shows the potential of nanotechnology for cancer treatment, both in chemotherapy and in surgery, where green lasers are already used. This work can be applied to drug resistant tumours, increasing the efficacy of treatment.

The Natural History and Science Museum of the University of Porto houses a collection of 45 models of fungi in papier-mâché from the 19th-century, which were used at the university until 2015 as didactic models. For the first time, the materials and techniques used in the production of a Boletus edulis model were studied (vernacular name: cep, porcini). These sculptures, made to life-size scale, are painted in colors similar to those of the represented species (white, brown, and light brown). They are fixed to a rectangular base, which is painted black, and to which moss has been pasted. To fully characterize each color, at the molecular level, a multi-analytical approach was used, combining energy-dispersive x-ray fluorescence spectroscopy (micro-XRF) with fingerprinting techniques of Raman microscopy (microRaman and handheld Raman) spectroscopy and microFourier transform infrared spectroscopy (microFTIR). The papier-mâché was prepared with a groundwood paper to which kaolin and a quartz-based material have been added to reinforce the structure. Raman microscopy also identified carbon black in it, which is possibly responsible for its grey color. The white color was unequivocally identified as lithopone by microRaman. This white paint was prepared in a proteinaceous tempera, with calcium carbonate having been identified as filler (by microFTIR). In the brown color, iron was identified by microXRF, pointing to the use of ocher, which was not possible to identify by microRaman and microFTIR. Regarding the black rectangular base, the moss was fixed using a collagen-based glue. The binding medium in this black is possibly a mixture of drying oil and protein. Again, XRF detected iron as the main element, but it was not possible to acquire a Raman spectrum due to the high fluorescence of the binder/varnish. Others, such as the writing inks, will also be discussed. The colors identified are in line with the best materials available for use by artists of that time. This new knowledge is fundamental to informing the choice of the best conservation strategies for the preservation of these extraordinary models.