Rocking of a rigid block freestanding on a flat pedestal

The seismic protection of objects contained within Museums is a topic of great interest, especially with reference to how they are displayed or stored. This problem is the same as that of a large class of non-structural components, such as mechanical and electrical hospital and laboratory equipment that could lose their functionality because of earthquakes. Statues and ceramics simply supported on the floor represent a significant set of case. In some cases, like the Bronzes of Riace, isolation systems have been developed. However, in general museum exhibits are not equipped with devices capable of mitigating the oscillations induced by possible earthquakes. The case study of a marble statue placed on a freestanding squat rigid pedestal is examined. The system of algebraic differential equations governing the problem has been derived and included in an ad-hoc numerical procedure. It is shown that the insertion of a squat rigid body with low frictional resistance at the lower interface with the floor, and high frictional resistance at the upper interface with the artifact significantly reduces the amplitude of the rocking response. As a result the artifact rocks without sliding on the rigid base that slides without rocking with respect to the floor. The numerical analysis performed can be a tool to help in the choice of the optimal friction values in the surfaces of the flat block, designed as a simple isolation system

Constitutive behaviour of quasi-brittle materials with anisotropic friction

This paper presents an approach to a constitutive model for anisotropic quasi-brittle materials, developed in the framework of rate independent softening plasticity, involving a yield criterion in which an anisotropic friction tensor is involved. It turns out to be useful for materials characterized by ultimate behaviour which varies according to the direction, such as composite materials, anisotropic rocks, textiles, masonry. A geometrical representation of the limit domain in the case of plane stress, together with the results of laboratory tests is presented and discussed

Rocking Analysis for the bell tower of Sant’anna in Cervino

In seismic prone areas ecclesiastical masonry complexes have shown a very high vulnerability, as detected after the last Italian earthquakes, such as those occurred in L'Aquila (2009), Emilia-Romagna (2012), Central Italy (2016), and Ischia (2017). These are particular types of aggregate buildings subjected often to partial collapses, due to the presence of highly vulnerable elements, like the bell towers. Preliminary analyses should including straightforward and quick methods are necessary. In this paper the bell tower vulnerability is analyzed taking into account the rocking behaviour of the tower only and considering the contribute of the entire ecclesiastical complex as a rigid body sliding with a fixed friction coefficient with respect to the foundations. It is shown that suitable values of maximum oscillations and horizontal displacements are obtained. The case study is the ecclesiastical complex of S. Anna in Cervino (Caserta, Italy)

On the homogenization of periodic beam-like structures

Abstract A homogenization method for periodic beam-like structures that is based on the unit cell force transmission modes is presented. Its main advantage is that to identify the principal vectors of the state transfer matrix corresponding to the transmission modes it operates directly on the sub-partitions of the unit cell stiffness matrix and allows to overcome the problems due to ill-conditioning of the transfer matrix. As case study, the Pratt girder is considered. Closed form solutions for the transmission modes of this girder are achieved and used into homogenization. Since the pure bending mode shows that the Pratt unit cell transmits two kinds of bending moments, one given by the axial forces and the other originated by nodal moments, the Timoshenko couple-stress beam is employed as substitute continuum. Finally, a validation of the proposed procedure is carried out comparing the predictions of the homogenized models with the results of a series of girder f.e. analyses

Viga vagão com seção transversal retangular de madeira reforçada com barra de aço

O sistema chamado de viga vagão formado por uma viga principal, um ou dois montantes e tirantes fixados nas extremidades da peça, resulta em um modelo estrutural leve, de fácil manuseio, boa rigidez e de boa capacidade mecânica. Além de avaliar a eficiência do sistema em relação à uma viga simples, também foi realizada a análise entre os resultados experimentais e os gerados por dois métodos de cálculo distintos. Nos três casos foi possível concluir que o sistema de viga vagão produz grande eficiência, pois para vigas de Angelim Vermelho (Dinizia excelsa Ducke) tem-se um ganho de rigidez médio de 623 %, e para as peças de tábuas de Pinus tem-se 518 % de ganho de rigidez

Análise de manifestações patológicas. Três estudos de caso / Analysis of building pathologies. Three case studies

Masonry buildings are the main part of the Architectural heritage in the World. The need of preservation for the historical memory, together with the exigence of fruition and use, has evidenced the need of appropriate analysis tools. In general, the stresses in masonry structures are usually considerably lower than those required for their material failure, so that the stability is mainly due to their shape and self weight. These aspects allowed in the past the simple realization of construction models in a reduced scale in order to assess the stability. As the history has pointed out, the behaviour of constructions is strongly linked to the workmanship and the good realization of the construction details. Local or global collapse can occur in fact due to pathologies arising during the construction or to bad realization of construction details. This paper deals with this last aspect, examining three different masonry buildings: the first one is a brick masonry building in Bologna: San Barbaziano Church, the others are two Roman domus in two different archaelogical sites in Campania: Villa Regina (Boscoreale, Napoli) and Villa dei Misteri (Pompeii, Napoli). The defects have been divided into two classes: structural defects and non structural ones. It is shown that structural defects can cause a global damage and could involve significant interventions

Management of patients with a failed kidney transplant: what should we do?

Abstract The number of kidney transplant recipients returning to dialysis after graft failure is steadily increasing over time. Patients with a failed kidney transplant have been shown to have a significant increase in mortality compared with patients with a functioning graft or patients initiating dialysis for the first time. Moreover, the risk for infectious complications, cardiovascular disease and malignancy is greater than in the dialysis population due to the frequent maintenance of low-dose immunosuppression, which is required to reduce the risk of allosensitization, particularly in patients with the prospect of retransplantation from a living donor. The management of these patients present several controversial opinions and clinical guidelines are lacking. This article aims to review the leading evidence on the main issues in the management of patients with failed transplant, including the ideal timing and modality of dialysis reinitiation, the indications for an allograft nephrectomy or the correct management of immunosuppression during graft failure. In summary, retransplantation is a feasible option that should be considered in patients with graft failure and may help to minimize the morbidity and mortality risk associated with dialysis reinitiation

IMPLICAÇÕES ÉTICAS E LEGAIS NA UTILIZAÇÃO DE CÉLULAS-TRONCO EMBRIONÁRIAS NO BRASIL

As clulas-tronco embrionrias (CTE) encontradas nos embries possuem a capacidade de se diferenciar em qualquer clula do corpo humano. As pesquisas com a CTE so realizadas com o intuito de encontrar a cura para diversas doenas. O problema que para realizar tais experincias requer-se a morte do embrio e adquire-se todo um carter tico e legal, por tratar-se da prpria vida humana. Diante dessa questo, objetivou-se com a presente pesquisa, apresentar as implicaes ticas e legais na utilizao de clulas tronco embrionrias no Brasil, em pesquisas para fins teraputicos. O foco principal desse discurso est na questo do que vem a ser o embrio, pessoa ou mera aglomerao de clulas? Cabe ao direito permitir ou no tal utilizao, e a tica, dizer se tal ato lcito ou fere o direito. O Brasil autorizou a utilizao dos embries humanos congelados em clnicas de fertilizao, desde que aprovados pelos pais, alegando que no se trata de um problema tico, mas do direito dos pais decidirem sobre o que fazer com o material biolgico por eles gerados

Identification and monitoring of Copy Number Variants (CNV) in monoclonal gammopathy

Monoclonal gammopathy of undetermined significance (MGUS) represents the pre-clinical stage of Multiple Myeloma (MM) with the 5% of MGUS progresses to MM. Although the progression from MGUS to MM has not been completely characterized, it is possible to monitor the DNA modifications of patients diagnosed with MGUS to detect early specific genomic abnormalities, including copy number variations (CNV). The CNVs of chromosome 1q and chromosome 13q are associated with a worse prognosis in MM.In the present study, we showed that it is possible to monitor the 1q21 gain and 13q deletion frequencies in gDNA using digital PCR. The CNV analysis of three cell lines with a well-characterized cytogenetic profile were compared with measures performed by a real-time PCR approach and with a digital PCR approach. Then, we analyzed CNVs in CD138+ plasma cells isolated from bone marrow of MGUS and MM patients.Our results show that digital PCR and targeted DNA monitoring represent a specific and accurate technique for the early detection of specific genomic abnormalities both in MM and in MGUS patients.Our results could represent a remarkable advancement in MM and MGUS diagnosis and in CNV analysis for the evaluation of the risk of progression from MGUS to MM

Association between Long COVID and Overweight/Obesity

Background: Long COVID is a syndrome characterized by the persistence of SARS-CoV-2 infection symptoms. Among HCWs, prolonged COVID symptoms could lead to the inability to perform work tasks. The aim of this study is to investigate 35-day long-COVID (35-LC) characteristics and risk factors in a one-year period. Methods: We carried out a retrospective cohort study during the COVID-19 pandemic at University Hospital of Bari. A total of 5750 HCWs were tested for close contact with a confirmed case, in the absence of personal protective equipment, or for symptom development. Results: Each positive HCW was investigated for cardiovascular risk factors or respiratory diseases. An amount of 352 HCWs (6.1%) were infected by SARS-CoV-2, and 168 cases evolved to long COVID. The 35-LC group showed mean BMI values higher than the non-35-LC group (25.9 kg/m2 vs. 24.8 kg/m2, respectively), and this difference was significant (p-value: 0.020). Moreover, HCWs who suffered from pulmonary disease (OR = 3.7, CL 95%: 1.35–10.53; p-value = 0.007) or overweight (OR = 1.6 CL 95%: 1.05–2.56; p-value = 0.029) had an increased risk of developing 35-LC. Conclusions: Long COVID is an emerging problem for hospital managers as it may reduce the number of HCWs deployed in the fight against COVID-19. High BMI and previous pulmonary disease could be risk factors for 35-LC development in exposed HCWs