Seismic vulnerability of churches in Faial and Pico islands, Azores

Earthquakes represent one of the main cause of serious damage and loss of historic and architectural heritage. Interventions to preserve these building should start with a careful knowledge and assessment of their seismic vulnerability, in order to support any needed retrofitting and strengthening measures. This paper proposes a procedure to register and diagnose of the level of damage on churches after the occurrence of an earthquake, and also to assess the seismic vulnerability of this type of construction. This procedure was applied to sixteen churches in the Azores islands which were hit by the July 9th 1998 earthquake. Belfries of church towers are elements with a particular seismic vulnerability. For this reason, and based on the Italian methodology proposed by the Linee Guida (2006), it is applied to belfries of two churches from Pico (Azores), a simplified mechanical model for assessment of seismic vulnerability of this type of structures

Characterization of a fully active N-terminal 37-kDa polypeptide obtained by limited tryptic cleavage of pig kidney D-amino acid oxidase.

In order to obtain further information on the structure of D-amino acid oxidase (EC 1.4.3.3), limited proteolysis experiments have been carried out on its apo-, holo-, and holoenzyme-benzoate forms. The enzyme is unsensitive to 10% (w/w) chymotrypsin, while incubation with 10% (w/w) trypsin, under nondenaturating conditions, produces inactivation and proteolysis patterns which are different for the three forms of enzyme analyzed. These results confirm the previously reported conformational changes which occur upon binding of coenzyme to the apoprotein, and of benzoate to holoenzyme. The stable 37.0-kDa polypeptide, obtained from the apo- and holoenzyme-benzoate complex upon cleavage of a C-terminal 2.0-kDa fragment, retains full catalytic activity with unaltered kinetic parameters, and the coenzyme binding properties of the native enzyme. These results are in agreement with the tentative localization of the FAD-binding domain in the N-terminal region of the enzyme, and with the hypothesis that the function of the C-terminal region of D-amino acid oxidase could be related to the import of the enzyme into the peroxisomes, as suggested by Gould et al. (Gould, S. J., Keller, G. A., and Subramani, S. (1988) J. Cell. Biol. 107, 897-905)

Endothelialization of a New Dacron Graft in an Experimental Model: Light Microscopy, Electron Microscopy and Immunocytochemistry

Two types of synthetic vascular grafts, Dacron Triaxial and Dacron Gelseal Triaxial, were implanted into both the common carotids of sheep. The animals were sacrificed 1, 2, 8, and 16 weeks after surgery. Multiple specimens, obtained from grafts and anastomoses, were studied by light microscopy, transmission and scanning electron microscopy. A parallel immunocytochemical analysis was performed on some specimens. Dacron Triaxial grafts failed to develop a complete neointimal coverage. Myofibroblasts and fibroblasts were the dominant cells in such synthetic graft. Moreover, focal areas of stripping, platelet deposition, and thrombosis were observed at 8 and 16 weeks. In contrast, a stable endothelial coverage developed on the Gelseal Triaxial grafts after 16 weeks

Healing of Prosthetic Arterial Grafts

Numerous synthetic biomaterials have been developed as vascular substitutes. In vitro, ex vivo and in vivo studies have demonstrated that in animals, selected materials, i.e., Dacron and ePTFE (expanded polytetrafluoroethylene) grafts, are successfully incorporated in both the large and the small caliber host arteries through a process which is generally referred to as graft healing. Morphologically, this process consists of a series of complex events including fibrin deposition and degradation, monocyte-macrophage recruitment and flow-oriented cell-layer generation, this last event being the complete endothelialization of the arterial substitute. In contrast to experimental animals, the flow surface of synthetic vascular grafts remains unhealed in humans, particularly in the small caliber conduits. Healing in man consists of graft incorporation by the perigraft fibrous tissue response with a surface covered by more or less compacted, cross-linked fibrin. It is therefore obvious that: i) marked differences in graft healing exist between animals and man; and ii) the usual mechanisms of graft endothelialization are partially ineffective in man. In order to guarantee the patency of synthetic vascular grafts for human small artery bypass, new strategies and approaches have recently been attempted. In particular, the endothelial cell seeding approach has been successfully accomplished in animals and is being experimented in human clinical studies. The problems and results of this biological approach are outlined in this paper

Development of a Rotation Device for Microvascular Endothelial Cell Seeding

A rotation device (RD) specifically designed to achieve sterile endothelial cell (EC) seeding of vascular grafts has been developed. The basic characteristics of the RD include: small dimensions, fully autoclavable components, and perfectly sealed graft holders. These features make it possible to maintain sterility during all the steps of EC seeding. This was documented by negativity of all bacteriological assays performed . Moreover, the RD can simultaneously support three vascular grafts with different lengths (20, 40, and 60 cm) and diameters (4-8 mm). EC seeding is performed in the climatized chamber (37 °C; 5 % C02) with constant rotation (0.1 -3 rpm). The rotation cycle can be completed automatically. The practical efficacy of the RD was investigated by seeding 2 x 105/cm2 of human microvascular EC on 20 cm length, 4 mm internal diameter (ID) fibronectin- coated polytetrafluoroethylene (ePTFE) grafts for 24 and 48 hours respectively . Further, the effect of a highly viscous plasma expander, i.e., haemagel, on cell retention was also evaluated. Results were not as favorable as expected. However, it should be emphasized that after 48 hours of eel! incubation by using the RD, 42 % of the initially seeded EC were still present and approximately 15 % were fully spread over the graft surface. Moreover, the 10 minute perfusion with haemagel did not decrease the number of adherent microvascular EC

Application of EPR Spectroscopy in TiO2 and Nb2O5 Photocatalysis

The interaction of light with semiconducting materials becomes the center of a wide range of technologies, such as photocatalysis. This technology has recently attracted increasing attention due to its prospective uses in green energy and environmental remediation. The characterization of the electronic structure of the semiconductors is essential to a deep understanding of the photocatalytic process since they influence and govern the photocatalytic activity by the formation of reactive radical species. Electron paramagnetic resonance (EPR) spectroscopy is a unique analytical tool that can be employed to monitor the photoinduced phenomena occurring in the solid and liquid phases and provides precise insights into the dynamic and reactivity of the photocatalyst under different experimental conditions. This review focus on the application of EPR in the observation of paramagnetic centers formed upon irradiation of titanium dioxide and niobium oxide photocatalysts. TiO2 and Nb2O5 are very well-known semiconductors that have been widely used for photocatalytic applications. A large number of experimental results on both materials offer a reliable platform to illustrate the contribution of the EPR studies on heterogeneous photocatalysis, particularly in monitoring the photogenerated charge carriers, trap states, and surface charge transfer steps. A detailed overview of EPR-spin trapping techniques in mechanistic studies to follow the nature of the photogenerated species in suspension during the photocatalytic process is presented. The role of the electron donors or the electron acceptors and their effect on the photocatalytic process in the solid or the liquid phase are highlighted

Experimental–computational study of carbon nanotube effects on mitochondrial respiration: in silico nano-QSPR machine learning models based on new Raman spectra transform with Markov–Shannon entropy invariants

[Abstract] The study of selective toxicity of carbon nanotubes (CNTs) on mitochondria (CNT-mitotoxicity) is of major interest for future biomedical applications. In the current work, the mitochondrial oxygen consumption (E3) is measured under three experimental conditions by exposure to pristine and oxidized CNTs (hydroxylated and carboxylated). Respiratory functional assays showed that the information on the CNT Raman spectroscopy could be useful to predict structural parameters of mitotoxicity induced by CNTs. The in vitro functional assays show that the mitochondrial oxidative phosphorylation by ATP-synthase (or state V3 of respiration) was not perturbed in isolated rat-liver mitochondria. For the first time a star graph (SG) transform of the CNT Raman spectra is proposed in order to obtain the raw information for a nano-QSPR model. Box–Jenkins and perturbation theory operators are used for the SG Shannon entropies. A modified RRegrs methodology is employed to test four regression methods such as multiple linear regression (LM), partial least squares regression (PLS), neural networks regression (NN), and random forest (RF). RF provides the best models to predict the mitochondrial oxygen consumption in the presence of specific CNTs with R2 of 0.998–0.999 and RMSE of 0.0068–0.0133 (training and test subsets). This work is aimed at demonstrating that the SG transform of Raman spectra is useful to encode CNT information, similarly to the SG transform of the blood proteome spectra in cancer or electroencephalograms in epilepsy and also as a prospective chemoinformatics tool for nanorisk assessmentXunta de Galicia; GRC2014/049Xunta de Galicia; R2014/03