Análise cromatográfica e identificação de marcadores de envelhecimento de documentos gráficos

Dissertação apresentada para obtenção do grau de Mestre em BioorgânicaA presente dissertação descreve o desenvolvimento de um método analítico para a identificação de compostos orgânicos voláteis (VOC’s) emitidos por materiais celulósicos, nomeadamente livros. O objectivo principal foi o estabelecimento de perfis químicos do material de origem, celulose, de modo a tornar possível a identificação de marcadores do tipo de celulose – celulose de algodão ou madeira, bem como do seu estado de conservação/degradação. Utilizou-se a micro-extracção em fase sólida associada à cromatografia gasosa e espectrometria de massa (HS-SPME-GC-MS). Para validação do método, foram estudados parâmetros experimentais: tipo de fibra, tempo de exposição, tempo de dessorção, temperaturas do injector e detector, programa cromatográfico, tendo sido igualmente estabelecidos os melhores parâmetros espectrométricos. Como resultado do estudo dos VOCs emitidos pelos livros foram identificados 22 compostos. Pela primeira vez, foram identificados marcadores de um dos tipos de celulose utilizada na manufactura de livros pertencentes ao património cultural. O estudo da quiralidade dos compostos foi pela primeira vez utilizado em materiais de interesse histórico, tendo-se constatado ser uma área importante, uma vez que apenas um dos enantiómeros de um dos compostos alvo está presente nos livros

DOENÇA PERIODONTAL MATERNA E PREMATURIDADE/BAIXO PESO AO NASCER: UMA METANÁLISE

OBJETIVO: Avaliar a associação entre doença periodontal (DP) e prematuridade/baixo peso ao nascer (PMBP).MATERIAL E MÉTODOS: Foi realizado um estudo de metanálise no qual foram empregadas as bases de dados PUBMED/Medline, Lilacs e SciELO  para selecionar estudos de caso-controle com ano de publicação no intervalo de tempo de  2001 a 2013.RESULTADOS: Dos 33 estudos de caso-controle elegíveis, 23 tiveram seus achados sumarizados na metanálise. O odds ratio da metanálise foi da ordem de 1,7 (95% IC [1,19 – 2,43],) apontando que gestantes com DP podem ter a chance elevada para terem filhos com PMBP ao serem comparadas àquelas sem DP.CONCLUSÃO: Os achados dessa metanálise sugerem que existe associação entre DP e PMBP

Mucopolysaccharidosis I, II, and VI: Brief review and guidelines for treatment

Mucopolysaccharidoses (MPS) are rare genetic diseases caused by the deficiency of one of the lysosomal enzymes involved in the glycosaminoglycan (GAG) breakdown pathway. This metabolic block leads to the accumulation of GAG in various organs and tissues of the affected patients, resulting in a multisystemic clinical picture, sometimes including cognitive impairment. Until the beginning of the XXI century, treatment was mainly supportive. Bone marrow transplantation improved the natural course of the disease in some types of MPS, but the morbidity and mortality restricted its use to selected cases. The identification of the genes involved, the new molecular biology tools and the availability of animal models made it possible to develop specific enzyme replacement therapies (ERT) for these diseases. At present, a great number of Brazilian medical centers from all regions of the country have experience with ERT for MPS I, II, and VI, acquired not only through patient treatment but also in clinical trials. Taking the three types of MPS together, over 200 patients have been treated with ERT in our country. This document summarizes the experience of the professionals involved, along with the data available in the international literature, bringing together and harmonizing the information available on the management of these severe and progressive diseases, thus disclosing new prospects for Brazilian patients affected by these conditions

Alterações neurológicas associadas a SARS-CoV-2: uma revisão de literatura: Associated neurological changes the SARS-CoV-2: a literature review

Introdução. A doença comumente conhecida por COVID-19 é capaz de ser encontrada em todos os órgãos e sistemas. Contudo o SNC pode ser afetado de forma que cause danos significativos aos que foram acometidos pela mesma. Desta forma, este trabalho é uma revisão acerca dos achados e suas manifestações para que possamos no futuro triar, buscar e analisar fatores neurologicamente afetados. Objetivo. Analisar e revisar matérias que possam auxiliar no detalhamento acerca de alterações neurológicas oriundas da COVID-19. Método. A estratégia utilizada contou com estudos, tendo por base uma análise em plataformas como o Google Acadêmico, PubMed, SciELO, Medical Subject Heading (MeSH), nas quais cada fonte de dados contou com um estudo acerca dos títulos, assuntos e tipos específicos na língua portuguesa e inglesa. Resultados. Foi possível ao longo de 16 artigos analisados, observar que grande parte da população analisada teve alterações, sejam elas leves como mialgia, disfunções de olfato e paladar, podendo a ter alterações graves como o Acidente Vascular Cerebral (AVC). Além disso, foi possível observar que pacientes com morbidades como a DM e a HAS tiveram maiores propensões a doenças cerebrovasculares. Conclusão. Este estudo oferece uma nova forma de pensar e analisar as alterações causadas pela COVID-19, associado com as alterações neurológicas. Com isso, podemos ajudar a identificar e classificar as possíveis alterações, a fim de auxiliar no combate a alterações severas

Nightside condensation of iron in an ultra-hot giant exoplanet

Ultra-hot giant exoplanets receive thousands of times Earth's insolation. Their high-temperature atmospheres (>2,000 K) are ideal laboratories for studying extreme planetary climates and chemistry. Daysides are predicted to be cloud-free, dominated by atomic species and substantially hotter than nightsides. Atoms are expected to recombine into molecules over the nightside, resulting in different day-night chemistry. While metallic elements and a large temperature contrast have been observed, no chemical gradient has been measured across the surface of such an exoplanet. Different atmospheric chemistry between the day-to-night ("evening") and night-to-day ("morning") terminators could, however, be revealed as an asymmetric absorption signature during transit. Here, we report the detection of an asymmetric atmospheric signature in the ultra-hot exoplanet WASP-76b. We spectrally and temporally resolve this signature thanks to the combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by -11+/-0.7 km s-1 on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside. In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. Iron must thus condense during its journey across the nightside.Comment: Published in Nature (Accepted on 24 January 2020.) 33 pages, 11 figures, 3 table

Direct evidence for phosphorus limitation on Amazon forest productivity

The productivity of rainforests growing on highly weathered tropical soils is expected to be limited by phosphorus availability1. Yet, controlled fertilization experiments have been unable to demonstrate a dominant role for phosphorus in controlling tropical forest net primary productivity. Recent syntheses have demonstrated that responses to nitrogen addition are as large as to phosphorus2, and adaptations to low phosphorus availability appear to enable net primary productivity to be maintained across major soil phosphorus gradients3. Thus, the extent to which phosphorus availability limits tropical forest productivity is highly uncertain. The majority of the Amazonia, however, is characterized by soils that are more depleted in phosphorus than those in which most tropical fertilization experiments have taken place2. Thus, we established a phosphorus, nitrogen and base cation addition experiment in an old growth Amazon rainforest, with a low soil phosphorus content that is representative of approximately 60% of the Amazon basin. Here we show that net primary productivity increased exclusively with phosphorus addition. After 2 years, strong responses were observed in fine root (+29%) and canopy productivity (+19%), but not stem growth. The direct evidence of phosphorus limitation of net primary productivity suggests that phosphorus availability may restrict Amazon forest responses to CO2 fertilization4, with major implications for future carbon sequestration and forest resilience to climate change

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 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 or ganism 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 ne glected 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 lostinfo:eu-repo/semantics/publishedVersio