Correlação entre o conteúdo inorgânico e a polimerização da matriz orgânica das resinas compostas para restaurações dentárias: uma revisão narrativa

Introduction: In recent years, resin-matrix composite materials have revealed a fast technological improvement for dental applications. However, there are still some drawbacks related to the chemical composition, polymerization, and mechanical properties of resin-matrix composites with consequences in long-term clinical success. Objective: This study aimed to perform a narrative review regarding the effects of inorganic fillers on the organic matrix polymerization of resin-matrix composites. Materials and Methods: A search was performed in PubMed using relevant related key terms related to the chemical composition, properties and polymerization of resin matrix composites. Relevant studies published between 2001 and 2021 were selected. Results: The studies included in the present research provided relevant information on the chemical composition and properties of resin composites and polymerization factors, including the time, wavelength mode, and equipment. Studies have reported that silica and silicate nano-scale particles improve light transmission through resin-matrix composites and the degree of conversion of monomers in the organic matrix. Micrometric particles with a high refractive index can decrease the degree of conversion of monomers in the organic matrix. Conclusion: The polymerization of resin-matrix composites is affected by light scattering due to the type of inorganic particles and the differences in refractive indexes of inorganic and organic contents.Introdução: Nos últimos anos, as resinas compostas têm sido melhoradas em termos tecnológicos, permitindo o alcance de melhores prognósticos na medicina dentária. Entretanto, subsistem algumas limitações relacionadas com a composição química e as propriedades das resinas compostas com consequências no sucesso clínico a longo prazo. Objetivo: O objetivo deste trabalho foi realizar uma revisão narrativa sobre a influência da componente inorgânica na polimerização da matriz orgânica das resinas compostas usadas para restauração dentária. Materiais e Métodos: A pesquisa foi realizada na plataforma PubMed utilizando termos de pesquisa relacionados com a composição química, propriedades e a polimerização das resinas compostas, para seleção de artigos relevantes ao tema. Resultados: Os estudos identificados reportam diferentes fatores relacionados com a polimerização incluindo modo, tempo, equipamento e a composição química das resinas compostas. Os estudos indicam que partículas nanométricas à base de sílica ou silicatos promovem uma maior transmissão de luz à matriz orgânica o que favorece a polimerização do material. Por outro lado, partículas micrométricas com um alto índice de refração podem diminuir o grau de conversão dos monómeros da matriz orgânica. Conclusão: A polimerização das resinas compostas é afetada pela dispersão da luz, devido ao tamanho das partículas inorgânicas e aos índices de refração da componente orgânica e inorgânica. De fato, um maior controlo da composição química e do tamanho de partículas inorgânicas aumenta o grau de polimerização das resinas compostas

Bottom trawl fishing footprints on the world’s continental shelves

Bottom trawlers land around 19 million tons of fish and invertebrates annually, almost one-quarter of wild marine landings. The extent of bottom trawling footprint (seabed area trawled at least once in a specified region and time period) is often contested but poorly described. We quantify footprints using high-resolution satellite vessel monitoring system (VMS) and logbook data on 24 continental shelves and slopes to 1,000-m depth over at least 2 years. Trawling footprint varied markedly among regions: from 50% in some European seas. Overall, 14% of the 7.8 million-km2 study area was trawled, and 86% was not trawled. Trawling activity was aggregated; the most intensively trawled areas accounting for 90% of activity comprised 77% of footprint on average. Regional swept area ratio (SAR; ratio of total swept area trawled annually to total area of region, a metric of trawling intensity) and footprint area were related, providing an approach to estimate regional trawling footprints when high-resolution spatial data are unavailable. If SAR was ≤0.1, as in 8 of 24 regions, there was >95% probability that >90% of seabed was not trawled. If SAR was 7.9, equal to the highest SAR recorded, there was >95% probability that >70% of seabed was trawled. Footprints were smaller and SAR was ≤0.25 in regions where fishing rates consistently met international sustainability benchmarks for fish stocks, implying collateral environmental benefits from sustainable fishing

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Histone H3.3 beyond cancer: Germline mutations in<em> Histone 3 Family 3A</em> and 3B cause a previously unidentified neurodegenerative disorder in 46 patients.

Although somatic mutations in Histone 3.3 (H3.3) are well-studied drivers of oncogenesis, the role of germline mutations remains unreported. We analyze 46 patients bearing de novo germline mutations in histone 3 family 3A (H3F3A) or H3F3B with progressive neurologic dysfunction and congenital anomalies without malignancies. Molecular modeling of all 37 variants demonstrated clear disruptions in interactions with DNA, other histones, and histone chaperone proteins. Patient histone posttranslational modifications (PTMs) analysis revealed notably aberrant local PTM patterns distinct from the somatic lysine mutations that cause global PTM dysregulation. RNA sequencing on patient cells demonstrated up-regulated gene expression related to mitosis and cell division, and cellular assays confirmed an increased proliferative capacity. A zebrafish model showed craniofacial anomalies and a defect in Foxd3-derived glia. These data suggest that the mechanism of germline mutations are distinct from cancer-associated somatic histone mutations but may converge on control of cell proliferation