Biocompatibilidade das principais ligas metálicas utilizadas em medicina dentária em Portugal

As ligas metálicas utilizadas em medicina dentária podem influenciar não apenas a qualidade e durabilidade das próteses e implantes dentários como também a saúde dos tecidos orais e até sistémicos. Antigamente os efeitos biológicos das ligas metálicas e materiais dentários eram ignorados em estudos e totalmente desconhecidos, porém com o passar do tempo observou-se a influência direta e indireta da biocompatibilidade destes metais e ligas metálicas no sucesso dos tratamentos dentários de reabilitação. O objetivo deste estudo é apresentar conteúdos atualizados e conceitos já conhecidos e comprovados através de uma revisão da literatura existente sobre o biocompatibilidade das ligas metálicas mais utilizadas em medicina dentária em Portugal. Para a presente revisão bibliográfica, foi realizada uma pesquisa bibliográfica com recurso a livros e artigos publicados em revistas, e que foram consultados nas Bibliotecas da Faculdade de Medicina Dentária da Universidade do Porto e da Universidade Fernando Pessoa. Procedeu-se à pesquisa por recurso aos motores de busca na internet, tais como, PubMed, Scielo, B-On e Medline, utilizando as seguintes palavras-chave, em conjunto ou individualmente: Ligas metálicas, prótese dentária, reabilitação dentária, reabilitação oral, biocompatibilidade, citotoxicidade, liberação, iões, titânio, cobalto, cromo¨. Foram selecionados artigos entre 1980 e 2017, com relevância para o presente trabalho de dissertação de Mestrado, escritos em Português e Inglês.Metal alloys used in dentistry can influence not only the quality and durability of dental prosthesis and dental implants as well as oral health and even systemic tissues. In the past years, the biological effects of metal alloys and dental materials have been ignored and unknown in scientific studies, but over the following years it could be observed the direct and indirect influences of the biocompatibility of those metals and metal alloys in dental rehabilitation treatments success. The aim of this study is organize and include an updated scientific content and known concepts and through a review of existing literature about the biocompatibility of metal alloys used in dentistry in Portugal. For this bibliographic review, a bibliographic research was performed with the use of books and articles published in journals, which were consulted in the libraries of the Dental Faculty of the University of Porto and the Fernando Pessoa University. The research was carried out by resource to internet search engines such as PubMed, Scielo, B-On and Medline, using the following keywords, jointly or individually: metal alloys, dental alloys, dental prosthesis, dental rehabilitation, oral rehabilitation, biocompatibility, release, ions, titanium, cobalt, chromium, nickel, dentistry. Articles were selected between 1980 and 2017, with relevance to the present work of the Master thesis, written in Portuguese and English

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead