1,112 research outputs found

    Seismic vulnerability of churches in Faial and Pico islands, Azores

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    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

    Estudio experimental comparativo de la estabilidad de distintos tutores externos

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    Se investigó la rigidez de 11 diferentes montajes de tutores externos usando un modelo experimental con tibias cadavéricas a las cuales se realizaba una osteotomía transversal mediodiafisaria perpendicular al eje longitudinal del hueso, creando entre ambos segmentos una brecha de 35 mm, simulando una fractura. Mediante dispositivos de medición diseñados y construidos especialmente para este estudio se logró cuantificar los desplazamientos que se producen en el foco de fractura ante cargas de compresión axial, torsión y flexiones anteroposterior y mediolateral. Se determinó en cada ensayo la carga segura y carga máxima previamente definidas. La mayor rigidez a la compresión axial se observó en el tutor Orthofix a la torsión y a la flexión anteroposterior en el Kronner biplanar y a la flexión mediolateral en el tutor AO triangulado. Se determina la rigidez total porcentual de cada montaje como índice que representa el funcionamiento promedio del mismo en todas las modalidades de carga. Se consideran las indicaciones, ventajas, complicaciones y fundamentalmente la biología de la consolidación ósea en referencia a los fijadores externos. Se concluye sobre el cuidado con que debe ser conducida la carga de un miembro con fractura inestable, ya que la mayoría de los montajes permiten más de 1 mm de movimiento en la brecha de la fractura con una carga axial baja.The stiffness of 11 different device configurations of external fixation was investigated in an experimental model using human cadaveric tibia. After application of the different devices, a diaphyseal osteotomy allowing removal of a 35 mm bone segment was performed in the specimens. Displacements of the bone fragments at the osteotomy site induced by compresion loading, torsion, and both anteroposterior and mediolateral flexion were measured with dispositives designed for this experiment. Maximal load and that required for inducing 1 mm displacement were recorded. The higher stiffness corresponded to the Orthofix fixator in axial compression, the Kronner biplanar device in anteroposterior flexion, and the triangular configuration of the AO device in mediolateral flexion. A total stiffness index of each configuration as an average of the behavior against all loading modahties was obtained. The indications, advantages, complications and the biology of bone consolidation wien regards to external fixation are considered. As conclusion, progressive loading of the extremity with unstable fracture requires a close monitorization, since most of the device configurations analyzed allow more than 1 mm displacement of bone fragments at the fracture site, even with low axial loading

    Petrographic & microstratigraphic analysis of mortar-based building materials from the Temple of Venus, Pompeii.

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    Recipes for mortar-based building materials may change over time and differ in various construction and restoration phases. They normally reflect craftsmen’s knowledge, availability of raw materials, and also the importance of the building in which they are found. The present research focuses on mortar-based materials from several construction and renovation phases of the Temple of Venus, at Pompeii, Italy, in order to identify any changes over time in production recipes

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

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    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

    New fully empirical calibrations of strong-line metallicity indicators in star-forming galaxies

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    We derive new empirical calibrations for strong-line diagnostics of gas-phase metallicity in local star-forming galaxies by uniformly applying the Te method over the full metallicity range probed by the Sloan Digital Sky Survey (SDSS). To measure electron temperatures at high metallicity, where the auroral lines needed are not detected in single galaxies, we stacked spectra of more than 110 000 galaxies from the SDSS in bins of log[O ii]/Hβ and log[O iii]/Hβ. This stacking scheme does not assume any dependence of metallicity on mass or star formation rate, but only that galaxies with the same line ratios have the same oxygen abundance. We provide calibrations which span more than 1 dex in metallicity and are entirely defined on a consistent absolute Te metallicity scale for galaxies. We apply our calibrations to the SDSS sample and find that they provide consistent metallicity estimates to within 0.05 dex.MC acknowledges financial support from INAF for his PhD fellowship. RM acknowledges support from the ERC Advanced Grant 695671 "QUENCH'' and support from the Science and Technology Facilities Council (STFC). Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society and the Higher Education Funding Council for England. The SDSS Web Site is http://www.sdss.org/

    Metodologia para a avaliação da vulnerabilidade sísmica do património religioso: caso de estudo - Faial e Pico, Açores

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    Os sismos representam uma das grandes causas de danos graves e perda do património histórico e arquitectónico. Qualquer intervenção de reabilitação destes edifícios deve partir de uma cuidada avaliação e análise da sua vulnerabilidade sísmica, de modo a desenvolver, se necessário, estratégias de reforço sísmico adequadas. O principal objectivo do presente artigo é estudar a vulnerabilidade sísmica do património religioso das ilhas do Faial e do Pico, nos Açores. Para tal, numa primeira parte deste trabalho, é proposta uma metodologia para o diagnóstico e registo do grau de dano em igrejas após a ocorrência de um sismo, assim como para a avaliação da vulnerabilidade associada a estas. A partir da análise dos danos observados em dezasseis igrejas afectadas pelo sismo de 9 de Julho de 1998 nos Açores, é elaborada uma base de dados que, para além de reunir as características de cada igreja estudada, apoia o cálculo simplificado do índice de dano, vulnerabilidade e coeficiente de segurança global. O campanário das torres sineiras é um elemento particularmente vulnerável aos sismos, devido à sua geometria típica. Por um lado, a existência de grandes aberturas a certos níveis produz tipicamente elementos verticais muito esbeltos. Por outro lado, a elevada concentração de massa no topo das torres também contribui para esta vulnerabilidade. Assim, na segunda parte deste trabalho, é aplicada a metodologia italiana, proposta na Linee Guida per la Valutazione e Reduzione del Rischio Sísmico del Patrimônio Culturale, aos campanários de duas igrejas localizadas na ilha do Pico, com base num modelo mecânico simplificado para a avaliação da vulnerabilidade deste tipo de estruturas. Com o trabalho desenvolvido, pretende-se contribuir para uma sistematização de processos de inspecção e registo de informação relativa a igrejas, com vista a apoiar estratégias de intervenção quer em situações de pós-sismo, quer na mitigação do risco sísmico destas estruturas

    Healing of Prosthetic Arterial Grafts

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    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

    p-TSA-Based DESs as “Active Green Solvents” for Microwave Enhanced Cyclization of 2-Alkynyl-(hetero)-arylcarboxylates: an Alternative Access to 6-Substituted 3,4-Fused 2-Pyranones

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    In this paper, we describe the use of p-TSA based Deep Eutectic Solvents (DESs) as alternative environmental-friendly \u201cactive\u201d solvents for the microwave-mediated synthesis of 6-substituted 3,4-fused 2-pyranones, and in particular isocoumarins, starting from 2-alkynyl-(hetero)arylcarboxylates. When the alkyne terminus bears a neutral or an electron-donating group (EDG), the reactions are fast, clean and highly regioselective, to give the 6-endo-dig cyclization products in good to excellent yields. For substrates bearing an electron-withdrawing group (EWG) on the alkyne end, the regioselectivity can be tuned by adding a small amount of silver(I) triflate as co-catalyst. DES was demonstrated to be reusable without loss of efficiency in terms of reaction yields. Based on experimental evidences and previous findings, two competitive mechanisms working simultaneously are proposed to explain the outcomes and the regioselectivity issues

    "Is this case of a very rare disease work-related?" A review of reported cases of Pacinian neuroma.

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    Objective In response to a request for a medicolegal opinion from an orthopaedic technician with pacinian neuroma of the hand, we conducted a systematic review of reported cases designed to assess whether this rare disease could be considered to be work-related.Methods We used Medline, Embase, Google Scholar, Google, and a manual search to identify reports of histologically confirmed pacinian neuroma of the hand manifesting after 15 years of age. Cases with available information (from article/authors) on personal history were considered eligible. We tabulated information on age/gender; localization and histopathologic features; signs/symptoms; history of local trauma; occupation, sports/hobbies or other physical exposures; right- or left-handedness; and outcome.Results We found 44 eligible cases (including the present referral). Of these, 21 (48%) followed a trauma [<6 months from onset/presentation (N=7); 0.5\u20132 years from onset (N=6); 652 years from onset (N=7); and timing unknown (N=1)] involving the same anatomic site. Three of these 21 traumas definitely occurred at work, and a further 2 cases occurred at the site of definite work-related repetitive microtrauma.Conclusions The results reinforce the concept that pacinian neuroma of the hand can follow local trauma or repetitive microtrauma. Implicated traumas were either recent or remote, and they sometimes occurred while performing manual tasks at work. We concluded that the referred case could plausibly be considered work-related
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