Shaking table tests of a two-storey log house

This paper presents the findings of an experimental campaign that was conducted to investigate the seismic behaviour of log houses. A two-storey log house designed by the Portuguese company Rusticasa® was subjected to a series of shaking table tests at LNEC, Lisbon, Portugal. The paper contains the description of the geometry and construction of the house and all the aspects related to the testing procedure, namely the pre-design, the setup, instrumentation and the testing process itself. The shaking table tests were carried out with a scaled spectrum of the Montenegro (1979) earthquake, at increasing levels of PGA, starting from 0.07g, moving on to 0.28g and finally 0.5g. The log house did not suffer any major damage and remained in working condition throughout the entire process. The preliminary analysis of the overall behaviour of the log house is also discussed.

Analysis of the seismic performance of a two storey log house

The dearth of knowledge on the load resistance mechanisms of log houses and the need for developing numerical models that are capable of simulating the actual behaviour of these structures has pushed efforts to research the relatively unexplored aspects of log house construction. The aim of the research that is presented in this paper is to build a working model of a log house that will contribute toward understanding the behaviour of these structures under seismic loading. The paper presents the results of a series of shaking table tests conducted on a log house and goes on to develop a numerical model of the tested house. The finite element model has been created in SAP2000 and validated against the experimental results. The modelling assumptions and the difficulties involved in the process have been described and, finally, a discussion on the effects of the variation of different physical and material parameters on the results yielded by the model has been drawn up.

Ciclo do luto normal

Comunicação oral, não escrita, não submetida a publicação.

Visual search for normal color and dichromatic observers using a unique distracter color

It is well known that color coding facilitates search and iden- tification in real-life tasks. The aim of this work was to compare reac- tion times for normal color and dichromatic observers in a visual search experiment. A unique distracter color was used to avoid abnormal color vision vulnerability to background complexity. Reaction times for nor- mal color observers and dichromats were estimated for 2◦ central vision at 48 directions around a white point in CIE L∗a∗b∗ color space for systematic examination on the mechanisms of dichromatic color percep- tion. The results show that mean search times for dichromats were twice larger compared to the normal color observers and for all directions. The difference between the copunctual confusion lines and the confusion direction measure experimentally was 5.5◦ for protanopes and 7.5◦ for deuteranopes.

Neuroendocrine factors regulate retinoic acid receptors in normal and hypoplastic lung development

Congenital diaphragmatic hernia (CDH) is characterised by a spectrum of lung hypoplasia and consequent pulmonary hypertension, leading to high morbidity and mortality rates. Moreover, CDH has been associated with an increase in the levels of pulmonary neuroendocrine factors, such as bombesin and ghrelin, and a decrease in the action of retinoic acid (RA). The present study aimed to elucidate the interaction between neuroendocrine factors and RA. In vitro analyses were performed on Sprague-Dawley rat embryos. Normal lung explants were treated with bombesin, ghrelin, a bombesin antagonist, a ghrelin antagonist, dimethylsulfoxide (DMSO), RA dissolved in DMSO, bombesin plus RA and ghrelin plus RA. Hypoplastic lung explants (nitrofen model) were cultured with bombesin, ghrelin, bombesin antagonist or ghrelin antagonist. The lung explants were analysed morphometrically, and retinoic acid receptor (RAR) α, β and γ expression levels were assessed via Western blotting. Immunohistochemistry analysis of RAR was performed in normal and hypoplastic lungs 17.5 days post-conception (dpc). Compared with the controls, hypoplastic lungs exhibited significantly higher RARα/γ expression levels. Furthermore considering hypoplastic lungs, bombesin and ghrelin antagonists decreased RARα/γ expression. Normal lung explants (13.5 dpc) treated with RA, bombesin plus RA, ghrelin plus RA, bombesin or ghrelin exhibited increased lung growth. Moreover, bombesin and ghrelin increased RARα/γ expression levels, whereas the bombesin and ghrelin antagonists decreased RARα/γ expression. This study demonstrates for the first time that neuroendocrine factors function as lung growth regulators, sensitising the lung to the action of RA through up-regulation of RARα and RARγ.

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.