Computational model to predict the temperature distribution produced by bone cement

Bone is the third frequent location for haematogenous dissemination of malignant tumors. Patients with multiple bone metastases are exponentially growing. Bone metastases, which are frequently diagnosed late, are associated to imminent and pathological bone fractures. Metastatic disease translates an advanced tumor stage and it has a high impact in patients’ quality of life and survival. The main objective is to study the thermal effect induced by the bone cement polymerization, in the bone metastatic tumor reduction and to understand the role of such procedure and its biomechanical stabilization. To assess the clinical effect, it is important to test this methodology before its application and obtain sustained results. In this work, a computational model was developed to predict the temperature distribution produced by cement polymerization, and verify the reduction of the metastatic tumor area due the thermal effect. Different simulations produced to evaluate the necrosis effect for two cement amount sizes introduced in a cortical and spongy bone tumor. The same computational models were reproduced introducing an endomedular nail in titanium and a femoral stem in cobalt-chrome material in pathological bone fractures.info:eu-repo/semantics/publishedVersio

The Density Effect in (W-S-W) Wood Connections with Internal Steel Plate and Passive Protection under Fire

The main objective of this work is to understand the fire behaviour of unprotected wood-to-wood connections with internal steel plate (W-S-W) in comparison with connections using passive protection with gypsum plasterboard. Passive fire protection uses systems that help prevent the spread of fire. Analytical methodologies according Eurocode 5 part 1-1 were used to the designed connections in different wood densities material. After that, to predict the fire exposure and the connection capacity a computational modelling was performed. Results of the temperature field and the char layer formation, for unprotected and protected members, were compared. Two different cross sections, only in wood or in wood-steel, were chosen to verify the evolution of charring rate effect.info:eu-repo/semantics/publishedVersio

A resource for sustainable management:<i>De novo</i> assembly and annotation of the liver transcriptome of the Atlantic chub mackerel, <i>Scomber colias</i>

Mackerels represent a valuable fishery worldwide. Their ample geographic distribution and capture levels make them an insightful model to address stock management strategies in the context of global changes. Yet, and despite recent impressive genome and transcriptome sequencing efforts from teleost species, available resources from the Scombridae family are comparatively scarce. Here, we generated the first high-quality de novo assembly of the liver transcriptome of the Atlantic chub mackerel (Scomber colias). Through the use of RNA-Seq Illumina technology, 111,124,228 clean reads were obtained for the liver transcriptome. De novo assembly resulted in 93,731 transcripts with an N50 of 1462 bp. This dataset provides an important insight into the context of fisheries management. Keywords: RNA-Seq, Scombridae, Stock management, Atlantic chub mackerel, Live

Fire behaviour of protected W-S-W connections with a steel plate as the central member and different dowels diameter

The main objective of this work is to present wood-steel-wood (W-S-W) connections in double-shear, joined by steel dowel fasteners and a steel plate as the central member. For each studied connection, different dowel diameters and external applied tensile loads in fire situation shall be taken in account. Considering the rules presented in Eurocode 5, part 1-1 and 1-2, the calculated number of dowels will be arranged in lines and columns and carry out an imposed spacing between the connectors. This work is intended to study the W-S-W connection exposed to fire using the standard curve ISO834. In the wood plates will be used a glue laminated wood, as yellow birch, with characteristics equals to GL28H. For protected connections three types of gypsum will be used in order to obtain a better insulation. Simplified equations from Eurocode 5, part 1-1 and 1-2, will be used to verify the behaviour of the connections at high temperature. A numerical procedure based on finite element method was also implemented to produce simulations focused on thermal analysis. The comparison of several results between analytical and numerical calculations showed a favourable accordance. The numerical model permits verify the effect of the steel dowels, steel plate and gypsum in the wood charring rate evolution. Even though the connection can resist for thirty minutes, is possible to observe the char layer both on protected and unprotected connection being the last the most affected.info:eu-repo/semantics/publishedVersio

Atas das 8as Jornadas de Segurança aos Incêndios Urbanos e as 3as Jornadas de Proteção Civil (8JORNINC-3JORPROCIV)

Este livro de ATAS contém os artigos apresentados às 8as Jornadas de Segurança aos Incêndios Urbanos e às 3as Jornadas de Proteção Civil (8JORNINC-3JORPROCIV), que decorreram no Porto, Portugal. Na presente edição das 8JORNINC-3JORPROCIV foram submetidos 50 trabalhos, tendo sido aceites 42. Os trabalhos foram distribuídos em 8 sessões paralelas temáticas, em adição a 2 sessões plenárias, apresentados no dia 2 de junho de 2023. O evento foi iniciado e promovido em Portugal, sob a organização do professor Doutor João Paulo Rodrigues, com as 1as Jornadas de Segurança aos Incêndios Urbanos, em 2005, na Universidade de Coimbra, bem como nos anos seguintes, as 2as Jornadas de Segurança aos Incêndios Urbanos em 2011 e as 3as Jornadas de Segurança aos Incêndios Urbanos em 2013, também na Universidade de Coimbra. As edições seguintes aconteceram em diferentes locais: as 4as Jornadas de Segurança aos Incêndios Urbanos em 2014, no Instituto Politécnico de Bragança; as 5as Jornadas de Segurança aos Incêndios Urbanos em 2016, no Laboratório Nacional de Engenharia Civil em Lisboa; as 6as Jornadas de Segurança aos Incêndios Urbanos e 1as Jornadas de Proteção Civil em 2018, na Universidade de Coimbra; e as 7as Jornadas de Segurança aos Incêndios Urbanos e 2as Jornadas de Proteção Civil, em 2021, no Instituto Politécnico de Castelo Branco. As 8JORNINC apresentam grande importância num contexto atual de vários e graves incêndios urbanos, florestais e de interface em Portugal. A pertinência do tema da segurança na prevenção e no combate a incêndios, quer pelas consequências emergentes deste tipo de acidentes, quer pela necessidade de redução das ocorrências, do número de vítimas mortais, feridos, prejuízos materiais, patrimoniais, ambientais e sociais, leva a que as Jornadas se destinem a um leque alargado de profissionais e público em geral. As 3JORPROCIV têm como objetivo promover conhecimentos nas áreas da prevenção civil, de riscos e planos de emergência. Pretendem assim, contribuir para a atualização dos conhecimentos técnicos e científicos da segurança e proteção civil, no âmbito do planeamento e prevenção perante cenários de crise e emergência. As Jornadas de Proteção Civil permitem partilhar um leque de conhecimentos multidisciplinares suscetíveis de impulsionar uma intervenção por parte de técnicos, especialistas e dos agentes da proteção civil. A visão interdisciplinar e integradora dos problemas e desafios que a proteção civil apresenta será refletida na prevenção e mitigação dos riscos inerentes a uma situação de acidente. Os trabalhos apresentados nesta edição, permitirão o avanço das 8JORNINC-3JORPROCIV, através da divulgação dos recentes desenvolvimentos e do conhecimento nos domínios da segurança ao incêndio e proteção civil. Por fim, a comissão organizadora das 8JORNINC-3JORPROCIV gostaria de agradecer: - o apoio dos patrocinadores e das instituições do Sistema Científico e Tecnológico; - a todos os autores que partilharam os seus excelentes trabalhos; - e aos elementos da Comissão Científica que auxiliaram no processo de revisão. Todos em conjunto, tornaram possível a realização destas Jornadas.info:eu-repo/semantics/publishedVersio

The heat transfer modelling for bone metastatic lesion minimization using two different cement types

Bone tumors grow when cells divide without any control, forming a tissue mass. Bone tumors could be benign or malignant, and primary or metastatic due to systemic cancer cells dissemination. They destroy bone and lead to pathological fractures. The main objective of this work is to study the thermal effect induced by the bone cement polymerization, in the bone metastatic tumor minimization. To assess the clinical effect, it is important to test this methodology before its application and obtain sustained results. In this work, a numerical model was developed to predict the temperature distribution produced by cement polymerization. Thus, distinct tests were produced for different two cements types and amounts introduced in a cortical and spongy bone metastatic lesion, with or without an intramedullary titanium nail. The bone cement was introduced to fill in a metastatic lytic lesion area, which the main objective is playing a promising role for bone tumor necrosis due to thermal effects and biomechanical stabilization for function and pain relief.info:eu-repo/semantics/publishedVersio

Effect of drill speed on the strain distribution during drilling of bovine and human bones

Drilling is an operation commonly required in orthopaedic surgery for insertion of screws and internal fixation of bone fractures. Induced damage is one of the undesired effects of drilling mainly due to the use of inadequate drilling parameters. During the recent years, scientists have been trying to describe the relationship between drilling parameters and bone injury. However, no studies have examined the level of strain generated in the bone during the drilling process. This paper focuses on the analysis of different drill speeds during drilling of fresh bovine femora and human cadaveric tibiae. The main contribution of this work is to determine how differences in applied drill speeds affect the strain of cortical tissue near the drilling site and the drill bit temperature. Strains were measured in ex-vivo material during the osteotomy preparation with three drill speeds (520, 900 and 1370 r.p.m.). Additionally, a thermographic camera was used to measure the drill bit temperature. As the drilling operations are blind in nature with unknown depth, the osteotomies were performed using a drill press machine without control of the feed rate or depth. Drill bit geometry was kept constant with 4 mm of diameter, point angle 120⁰ and helix angle 30⁰. The tests were conducted at room temperature without applying cooling at the drilling zone. Bone strains near to the drilling sites were recorded with high accuracy using linear strain gages mounted around the diaphyseal cortex. It was noted that the bone strain and drill bit temperature increased with an increasing drill speed. Human and bovine bone samples presented significantly different levels of strain and temperature. Both strain and temperature were higher when drilling bovine femora than when drilling human cadaveric tibiae

Numerical thermal study in bone tumor lesion

With the evolution of science and new diagnostic technologies, it was possible to observe a continuous improvement in the treatments in general and in the aid of the patients' quality of life. Malignant tumors can be primary or secondary (metastases), with abnormal growth of cells able to invade other types of tissues and organs through systemic dissemination. Sarcomas are rare primary malignancies formed from mesenchymal tissue and often located at the extremities. In this work, the main objective is to evaluate the minimization of the evolution of bone tumor lesion through the injection of bone cement, filling in the space of the lytic tumor lesion. This methodology allows to verify at the adjacent cement – bone tissue interface, an increase in temperature that can control the local growth of bone metastasis. Different computational models, obtained by medical image processing, will be carried out for two analyses (patient younger than 70 years and older than 70 years). The computational model allows a transient thermal analysis using the finite element method. The temperature results may determine the thermal necrosis effect in the bone tumor lesion. Results will be compared using three different bone cements.info:eu-repo/semantics/publishedVersio

Exacerbated inflammatory cellular immune response characteristics of HAM/TSP is observed in a large proportion of HTLV-I asymptomatic carriers

BACKGROUND: A small fraction of Human T cell Leukemia Virus type-1 (HTLV-I) infected subjects develop a severe form of myelopathy. It has been established that patients with HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) show an exaggerated immune response when compared with the immunological response observed in HTLV-I asymptomatic carriers. In this study the immunological responses in HAM/TSP patients and in HTLV-I asymptomatic carriers were compared using several immunological assays to identify immunological markers associated with progression from infection to disease. METHODS: Immunoproliferation assays, cytokine levels of unstimulated cultures, and flow cytometry analysis were used to evaluate the studied groups. Nonparametric tests (Mann-Whitney U test and Wilcoxon matched-pairs signed ranks) were used to compare the difference between the groups. RESULTS: Although both groups showed great variability, HAM/TSP patients had higher spontaneous lymphoproliferation as well as higher IFN-γ levels in unstimulated supernatants when compared with asymptomatic carriers. Flow cytometry studies demonstrated a high frequency of inflammatory cytokine (IFN-γ and TNF-α) producing lymphocytes in HAM/TSP as compared to the asymptomatic group. This difference was accounted for mainly by an increase in CD8 cell production of these cytokines. Moreover, the HAM/TSP patients also expressed an increased frequency of CD28-/CD8+ T cells. Since forty percent of the asymptomatic carriers had spontaneous lymphoproliferation and IFN-γ production similar to HAM/TSP patients, IFN-γ levels were measured eight months after the first evaluation in some of these patients to observe if this was a transient or a persistent situation. No significant difference was observed between the means of IFN-γ levels in the first and second evaluation. CONCLUSIONS: The finding that a large proportion of HTLV-I carriers present similar immunological responses to those observed in HAM/TSP, strongly argues for further studies to evaluate these parameters as markers of HAM/TSP progression