PDMS biofunctionalization study for the development of a microfluidic device: Application to salivary cortisol

The authors acknowledge to Sofia Neves from ICVS for her help in the antibodies selection.

Patterned CNT-PDMS nanocomposites for flexible pressure sensors

This paper reports the fabrication process and characterization of a flexible pressure sensor based on polydimethylsiloxane (PDMS) and multi-walled carbon nanotubes (CNT-PDMS). The proposed approach relies on patterned CNT-PDMS nanocomposite strain gauges fabricated with SU-8 microstructures (with the micropatterns) in a low‑cost and simple fabrication process. This nanocomposite polymer is mounted over a PDMS membrane, which, in turn, lies on top of a PDMS diaphragm like structure. This configuration enables the PDMS membrane to bend when pressure is applied, thereby affecting the nanocomposite strain gauges, effectively changing their electrical resistance. Carbon nanotubes have several advantages such as excellent mechanical properties, high electrical conductivity and thermal stability. Furthermore, the measurement range of the proposed sensor can be adapted according to the application by varying the CNTs content and geometry of microstructure. In addition, the sensor’s biocompatibility, low cost and simple fabrication makes it very appealing for biomechanical strain sensing. The sensor’s sensitivity was about 0.073%ΔR/mmHg.

Development of an intelligent earthwork optimization system

Tese de Doutoramento em Engenharia Civil.

Green's relations, regularity and abundancy for semigroups of quasi-onto transformations

Let V be an infinite-dimensional vector space and for every infinite cardinal n such that n≤dimV, let AE(V,n) denote the semigroup of all linear transformations of V whose defect is less than n. In 2009, Mendes-Gonçalves and Sullivan studied the ideal structure of AE(V,n). Here, we consider a similarly-defined semigroup AE(X,q) of transformations defined on an infinite set X. Quite surprisingly, the results obtained for sets differ substantially from the results obtained in the linear setting.

Divulgação de boas práticas como estratégia de marketing na construção

Dissertação de mestrado integrado em Engenharia Civil

A novel hanging spherical drop system for the generation of cellular spheroids and high throughput combinatorial drug screening

We propose a novel hanging spherical drop system for anchoring arrays of droplets of cell suspension based on the use of biomimetic superhydrophobic flat substrates, with controlled positional adhesion and minimum contact with a solid substrate. By facing down the platform, it was possible to generate independent spheroid bodies in a high throughput manner, in order to mimic in vivo tumour models on the lab-on-chip scale. To validate this system for drug screening purposes, the toxicity of the anti-cancer drug doxorubicin in cell spheroids was tested and compared to cells in 2D culture. The advantages presented by this platform, such as feasibility of the system and the ability to control the size uniformity of the spheroid, emphasize its potential to be used as a new low cost toolbox for high-throughput drug screening and in cell or tissue engineering.

Incorporation of antimicrobial peptides on functionalized cotton gauzes for medical applications

A large group of low molecular weight natural compounds that exhibit antimicrobial activity has been isolated from animals and plants during the past two decades. Among them, peptides are the most widespread resulting in a new generation of antimicrobial agents with higher specific activity. In the present study we have developed a new strategy to obtain antimicrobial wound-dressings based on the incorporation of antimicrobial peptides into polyelectrolyte multilayer films built by the alternate deposition of polycation (chitosan) and polyanion (alginic acid sodium salt) over cotton gauzes. Energy dispersive X ray microanalysis technique was used to determine if antimicrobial peptides penetrated within the films. FTIR analysis was performed to assess the chemical linkages, and antimicrobial assays were performed with two strains: Staphylococcus aureus (Gram-positive bacterium) and Klebsiella pneumonia (Gram-negative bacterium). Results showed that all antimicrobial peptides used in this work have provided a higher antimicrobial effect (in the range of 4 log–6 log reduction) for both microorganisms, in comparison with the controls, and are non-cytotoxic to normal human dermal fibroblasts at the concentrations tested.

O papel do transporte público nos padrões de mobilidade no acesso a um campus universitário

Dissertação de mestrado integrado em Engenharia Civil

Age effects on EEG correlates of the Wisconsin card sorting test

Body and brain undergo several changes with aging. One of the domains in which these changes are more remarkable relates with cognitive performance. In the present work, electroencephalogram (EEG) markers (power spectral density and spectral coherence) of age-related cognitive decline were sought whilst the subjects performed the Wisconsin Card Sorting Test (WCST). Considering the expected age-related cognitive deficits, WCST was applied to young, mid-age and elderly participants, and the theta and alpha frequency bands were analyzed. From the results herein presented, higher theta and alpha power were found to be associated with a good performance in the WCST of younger subjects. Additionally, higher theta and alpha coherence were also associated with good performance and were shown to decline with age and a decrease in alpha peak frequency seems to be associated with aging. Additionally, inter-hemispheric long-range coherences and parietal theta power were identified as age-independent EEG correlates of cognitive performance. In summary, these data reveals age-dependent as well as age-independent EEG correlates of cognitive performance that contribute to the understanding of brain aging and related cognitive deficits.

Os desafios da comunicação integrada no grupo dst: fazer negócios a falar de cultura

Relatório de estágio de mestrado em Ciências da Comunicação (área de especialização em Publicidade e Relações Públicas)

Regulamentação, concentração e instituições bancárias em contexto de crise

Dissertação de mestrado em Economia Monetária, Bancária e Financeira

Financiamento bancário e o desempenho das empresas em portugal: qual a relação?

Dissertação de mestrado em Economia Monetária, Bancária e Financeira

Influence of different fibers on the change of pore pressure of self-consolidating concrete exposed to fire

The focus of this paper is given to investigate the effect of different fibers on the pore pressure of fiber reinforced self-consolidating concrete under fire. The investigation on the pore pressure-time and temperature relationships at different depths of fiber reinforced self-consolidating concrete beams was carried out. The results indicated that micro PP fiber is more effective in mitigating the pore pressure than macro PP fiber and steel fiber. The composed use of steel fiber, micro PP fiber and macro PP fiber showed clear positive hybrid effect on the pore pressure reduction near the beam bottom subjected to fire. Compared to the effect of macro PP fiber with high dosages, the effect of micro PP fiber with low fiber contents on the pore pressure reduction is much stronger. The significant factor for reduction of pore pressure depends mainly on the number of PP fibers and not only on the fiber content. An empirical formula was proposed to predict the relative maximum pore pressure of fiber reinforced self-consolidating concrete exposed to fire by considering the moisture content, compressive strength and various fibers. The suggested model corresponds well with the experimental results of other research and tends to prove that the micro PP fiber can be the vital component for reduction in pore pressure, temperature as well spalling of concrete.

A comunicação em organizações virtuais: o paradigma digital

Dissertação de mestrado em Ciências da Comunicação (área de especialização em Publicidade e Relações Públicas)

Self-esteem, assertiveness and resilience in adolescents institutionalized

The institutionalization of children and adolescents has been an increasingly visible problem in modern society. Unfavourable socio-economic conditions have been joining the behavior problems and school absenteeism. When the family fails in its competence for education, social security or the Court withdraws the child or adolescent to a host institution. The aim of this research was to characterize self-esteem, assertiveness and resilience of institutionalized adolescents in the northern region of Portugal and to establish associations with these dependent variables and gender, scholar level and duration of the institutionalization. For the purpose of this study a wider questionnaire was carried out, and validated with a smaller group. It was a transversal study following a predominantly quantitative methodology, with a convenience sample. The sample included 101 adolescents (55 female and 46 males) from eight institutions, aged between 11 to 21 years old (average 15.45). For self-esteem the Rosenberg Self-Esteem Scale (Rosenberg, 1965), already validate for Portuguese adolescents, was used. For assertiveness and resilience it was applied the Global Evaluation Scale of Assertiveness and the Global Evaluation Scale of Resilience (Jardim & Pereira, 2006) we previously adapted and validated for adolescents. Collected data was introduced in a SPSS database. A descriptive analysis was done to characterize the sample concerning all the variables. To establish associations between individual factors and dependent variables t test, correlations and non-parametric test were applied. Results indicated a relatively low self-esteem (28.03), with girls having a lower value than boys, without significant differences. No correlations were found between self-esteem and the time in the institution. Assertiveness of the sample is average (23.97) and higher for girls than boys, with a positive significant correlation with the scholar grade. Also the resilience is average (25.97), having girls a little lower mean than boys and no significant differences or correlations were found.