Continuous wave terahertz (CW THz) imaging, is a variant of terahertz imaging that has been gaining scientific
and technological relevance in multiple areas. In this paper the fundamental phenomena of CW THz were
studied and a mathematical model was developed that successfully describes the Fabry–Perot interference for
such a system, opening the possibility for measurement of thicknesses and surface curvatures. The capabilities
of the system were tested using different types of defects, such as voids, water infiltrations and thin metallic
wires. The interactions between different materials, features and the radiation beam were numerically studied
using finite element method and the results agreed with the experiments. By comparing the results with other
Non-Destructive Testing methods, it was found that CW THz imaging is particularly interesting to image water
infiltrations and composite materials that incorporate conductive wires.

Design, research, and development of new and improved smart multifunctional devices is one of the main topics in the advanced functional materials agenda for the next decade. Smart materials that can be triggered by external stimuli are seen with high potential for innovative treatments and improved drug delivery systems by regulatory agencies like the FDA and EMA. The incorporation of magnetic nanostructures into complex systems produces multifunctional devices that can be spatiotemporally controlled by an external magnetic field. These magneto-responsive devices can be used for a multitude of biomedical applications, from diagnostic to the treatment of tumors, and are actively being developed and tested for cancer theranostics. Herein, we review the development of magneto-responsive devices for cancer theranostics, starting from the most straightforward architecture, single nanoparticles. We give some theoretical concepts about the design and production of such systems while providing a critical review of applications in clinical practice. Naturally, the review evolves to more complex architectures, from one-dimensional to three-dimensional magneto-responsive systems, demonstrating higher complexity and multifunctionality, and consequently, higher interest for clinical practice. The review ends with the main challenges in the design and engineering of magneto-responsive devices for cancer theranostics and future trends in this biomedical field.

Electronic controlled drug release from fibres was studied using ibuprofen as a model drug, one of the most popular analgesics, to impregnate gauze and cellulose acetate (CA) membranes. Conductivity in the range of 1–10 mS cm−1 was obtained in polypyrrole (Ppy) functionalised gauze and CA fibres, providing voltage-controlled drug release in a system consisting of Ppy/Ibuprofen/Ppy membranes and an Ag electrode. SEM images evidenced the Ppy adhesion to fibres and Micro Raman spectra proved drug incorporation and release. A small wound adhesive built with these membranes retains ibuprofen at 1.5 V and quickly releases it when −0.5 V is applied.

Electronic noses (e-noses) mimic the complex biological olfactory system, usually including an array of gas sensors to act as the olfactory receptors and a trained computer with signal-processing and pattern recognition tools as the brain. In this work, a new stimuli-responsive material is shown, consisting of self-assembled droplets of liquid crystal and ionic liquid stabilised within a fish gelatin matrix. These materials change their opto/electrical properties upon contact with volatile organic compounds (VOCs). By using an in-house developed e-nose, these new gas-sensing films yield characteristic optical signals for VOCs from different chemical classes. A support vector machine classifier was implemented based on 12 features of the signals. The results show that the films are excellent identifying hydrocarbon VOCs (toluene, heptane and hexane) (95% accuracy) but lower performance was found to other VOCs, resulting in an overall 60.4% accuracy. Even though they are not reusable, these sustainable gas-sensing films are stable throughout time and reproducible, opening several opportunities for future optoelectronic devices and artificial olfaction systems.

The following dissertation studies the behavior of flat slabs when subjected to constant vertical loads and cyclic horizontal displacements, as a continuation of previous studies developed at FCT/UNL. The main focus of this research is to study the influence of flexural reinforcement on the seismic response of flat slabs. Therefore, three reinforced concrete flat slabs with varying flexural reinforcement ratio were tested, two having the same top reinforcement ratio of !=0,64% and one with !=1,34%. One of the specimens with lower longitudinal ratio was reinforced with studs as specific punching shear reinforcement. All slabs had overall dimensions of 4,15 × 1,85 × 0,15 m3 and a gravity shear ratio, ratio between the gravity load and the punching shear resistance, approximately equal to 55%. For a more complete analysis the results obtained were compared to two other specimens from previous experimental campaigns also conducted at FCT/UNL. These two slabs were designed with top flexural reinforcement ratio (!=0,96%) that lies between the two tested in this dissertation, one with no shear-reinforcement and the other with headed studs. Results showed that the reduction of flexural reinforcement resulted in a more ductile behavior of the specimens and in a higher drift capacity. The high flexural ratio added to one specimen improved the maximum unbalanced moment capacity but also made the slab fail in a more brittle mode. As expected, the specimen with shear headed studs supported the highest drifts and ended up not failing during this experimental campaign, reaching the test setup upper limit.

The delivery of multiple anti-cancer agents holds great promise for better treatments. The present work focuses on developing multifunctional materials for simultaneous and local combinatory treatment: Chemotherapy and hyperthermia. We first produced hybrid microgels (MG), synthesized by surfactant-free emulsion polymerization, consisting of Poly (N-isopropyl acrylamide) (PNIPAAm), chitosan (40 wt.%), and iron oxide nanoparticles (NPs) (5 wt.%) as the inorganic component. PNIPAAm MGs with a hydrodynamic diameter of about 1 μm (in their swollen state) were successfully synthesized. With the incorporation of chitosan and NPs in PNIPAAm MG, a decrease in MG diameter and swelling capacity was observed, without affecting their thermosensitivity. We then sought to produce biocompatible and mechanically robust membranes containing these dual-responsive MG. To achieve this, MG were incorporated in poly (vinyl pyrrolidone) (PVP) fibers through colloidal electrospinning. The presence of NPs in MG decreases the membrane swelling ratio from 10 to values between 6 and 7, and increases the material stiffness, raising its Young modulus from 20 to 35 MPa. Furthermore, magnetic hyperthermia assay shows that PVP-MG-NP composites perform better than any other formulation, with a temperature variation of about 1 °C. The present work demonstrates the potential of using multifunctional colloidal membranes for magnetic hyperthermia and may in the future be used as an alternative treatment for cancer.

The behavior of flat slab – column connections under seismic-type loading is complex and not exhaustively studied. Among the many variables involved, this paper focuses on the influence of flexural reinforcement on the seismic performance of such connections. Three specimens were tested and analyzed in conjunction with two previously published specimens tested under similar conditions, under constant vertical loading and cyclic horizontal displacements, resulting in a total of five specimens. Among these specimens, the top flexural reinforcement varied from 0.64% to 1.34% and the approximate value of applied gravity shear ratio (GSR, equal to the ratio between the applied gravity load and the punching shear resistance) was around 55%. Two of the specimens (low and median reinforcement ratio) were also reinforced with headed studs against punching shear to study the unbalanced moment transfer capacity of the slab – column connections. The specimens are described and analyzed in detail. The results show that the performance under cyclic loading is affected by the amount of flexural reinforcement, even though GSR was almost the same for all specimens. It is shown that current code-based approaches for the estimation of unbalanced moment capacity, as well as drift capacity, are generally safe sided for the specimens under investigation but do not fully capture the trends observed in the experimental campaign.

Engineering drug delivery systems (DDS) aim to release bioactive cargo to a specific site within the human body safely and efficiently. Hydrogels have been used as delivery matrices in different studies due to their biocompatibility, biodegradability, and versatility in biomedical purposes. Microparticles have also been used as drug delivery systems for similar reasons. The combination of microparticles and hydrogels in a composite system has been the topic of many research works. These composite systems can be injected in loco as DDS. The hydrogel will serve as a barrier to protect the particles and retard the release of any bioactive cargo within the particles. Additionally, these systems allow different release profiles, where different loads can be released sequentially, thus allowing a synergistic treatment. The reported advantages from several studies of these systems can be of great use in biomedicine for the development of more effective DDS. This review will focus on in situ injectable microparticles in hydrogel composite DDS for biomedical purposes, where a compilation of different studies will be analysed and reported herein.

The present paper regards the preparation and characterization of Pluronic F127 + F68/water/poly (ε-caprolactone) microcapsules (MCs) composite systems for tissue repair. The first part of the work relates to the production of poly(ε-caprolactone) (PCL) MCs via water-in-oil-in-water (W/O/W) double emulsion system combined with solvent evaporation method. The study of different process parameters in the final MCs characteristics and their drug release profile is herein reported. Different percentages of PCL, emulsion stabilizer, and volume proportions of the emulsion constituents have been tested, leading to considerable differences in the MCs size distributions. The selected MCs, containing an aqueous solution of methylene blue (MB) as a model drug, were then used to fill a Pluronic F127 + F68/water system leading to the final composite system (5 and 10 wt % MB loaded PCL MCs). The composite systems were characterised in the second part of the work in terms of its rheological behaviour and drug release performance. They were found to gellify at 30 °C, and present an extended drug release to a total of 18 days. The models that best define the release profiles were also studied, with the release of MB occurring mostly by Fick diffusion and polymer chain relaxation. Pluronic F127 + F68/water/poly (ε-caprolactone) MCs composite system is shown to be a promising injectable system, with two different drug release rates, for tissue repair.