A user-friendly digital tool for the structural assessment of historic domes: the case study of Saint Peter in Rome

This paper presents a digital tool for the rapid structural assessment of historic masonry domes. It is especially suited for masonry domes that present long meridian cracks, ergo each partitioned element governed by a pushing failure mode. The proposed procedure considers a Heyman's no-tension mechanical model has been implemented within a commercial user-friendly visual programming environment. The numerical approach consists of a parametric modelling of the failure mechanism and, therefore, exploring the domain of possible solutions using the theorems of the limit analysis. Hence, a heuristic search method is subsequently adopted to refine the geometry of the collapse mechanism and to compute the value of the horizontal trust. The validation of the developed approach has been achieved considering the Saint Peter's dome. As reported in the literature, the behaviour of the Saint Peter's dome gradually shifted from a rigid shell-type - stiffened by hoop stresses -, towards a pushing type of dome partitioned by long meridian cracks. The study also evaluated the structural integrity of the drum. In converse with more time-consuming and advanced methods of analysis, the present procedure allows the users to perform a structural assessment of a historic masonry dome in a fast and computationally efficient manner. The developed digital tool will be freely available from a web archive hosted by the University of Minho and, therefore, easily able to reach students, researchers and structural engineers

Paracoccidioidomicose pulmonar: aspectos na tomografia computadorizada de alta resolução High-resolution computed tomography findings in pulmonary paracoccidioidomycosis

O comprometimento pulmonar na paracoccidioidomicose é muito freqüente, podendo até ser a única manifestação da doença. Neste trabalho são analisados os aspectos encontrados nas tomografias computadorizadas de alta resolução do tórax de 30 pacientes com paracoccidioidomicose confirmada. Por meio desta análise foram determinados os achados mais comuns e suas formas de apresentação e distribuição nos pulmões. Os aspectos mais freqüentemente observados foram: espessamento esparso de septos interlobulares (96,7%), opacidades em vidro fosco (66,7%), nódulos (60%), aumento irregular do espaço aéreo (enfisema paracicatricial) (56,7%), espessamento de paredes brônquicas (46,7%), espessamento pleural (36,7%), cavidades (36,7%), dilatação da traquéia (33,3%), distorção arquitetural (30%), consolidação do espaço aéreo (30%), bandas parenquimatosas (23,3%), reticulado intralobular (13,3%) e espessamento irregular do interstício axial peri-hilar (10%). A radiografia do tórax apresenta limitada capacidade de avaliar doenças pulmonares difusas, tornando a tomografia computadorizada de alta resolução do tórax essencial para avaliação dos pacientes com paracoccidioidomicose pulmonar.<br>Pulmonary disease in paracoccidioidomycosis is very common and in some cases can be the sole manifestation of the disease. We studied the findings observed in 30 patients with pulmonary paracoccidioidomycosis submitted to high-resolution computed tomography in order to determine the most frequent findings, presentation patterns and distribution of paracoccidioidomycosis lesions in the lungs. The most frequent findings observed on high-resolution computed tomography were: interlobular septal thickening (96.7%), ground-glass opacities (66.7%), nodules (60%), irregular air-space enlargement (56.7%), bronchial wall thickening (46.7%), pleural thickening (36.7%), cavitation (36.7%), tracheal dilatation (33.3%), architectural distortion (30%), air-space consolidation (30%), parenchymal bands (23.3%), intralobular reticulate (13.3%) and hilar interstitial thickening (10%). Chest X-rays allow limited evaluation of diffuse pulmonary diseases, and hence high-resolution computed tomography is an essential method for studying patients with pulmonary paracoccidioidomycosis

Interaction of transmembrane-spanning segments of the a2-adrenergic receptor with model membranes

Adrenergic receptors are integral membrane proteins involved in cellular signalling that belong to the G protein-coupled receptors. Synthetic peptides resembling the putative transmembrane (TM) segments TM4, TM6 and TM7, of the human alpha2-adrenergic receptor subtype C10 (P08913) and defined lipid vesicles were used to assess protein-lipid interactions that might be relevant to receptor structure/function. P6 peptide contains the hydrophobic core of TM6 plus the N-terminal hydrophilic motif REKR, while peptides P4 and P7 contained just the hydrophobic stretches of TM4 and TM7, respectively. All the peptides increase their helical tendency at moderate concentrations of TFE (30-50%) and in presence of 1,2-dielaidoyl-sn-glycero-3-phosphatidylethanolamine (DEPE) lipids. However, only P6 displays up to 19% of alpha-helix in the presence of just the DEPE lipids, evidences a transmembrane orientation and stabilizes the Lalpha lipid phase. Conversely, P4 and P7 peptides form only stable beta-sheet structures in DEPE and favour the non-lamellar, inverted hexagonal (H(II)) phase of DEPE by lowering its phase transition temperature. This study highlights the potential of using synthetic peptides derived from the amino acid sequence in the native proteins as templates to understand the behaviour of the transmembrane segments and underline the importance of interfacial anchoring interactions to meet hydrophobic matching requirements and define membrane organization