Poly(borosiloxanes) as precursors for carbon fiber ceramic matrix composites

Ceramic matrix composites (CMCs), constituted of a silicon boron oxycarbide (SiBCO) matrix and unidirectional carbon fiber rods as a reinforcement phase, were prepared by pyrolysis of carbon fiber rods wrapped in polysiloxane (PS) or poly(borosiloxane) (PBS) matrices. The preparation of the polymeric precursors involved hydrolysis/condensation reactions of alkoxysilanes in the presence and absence of boric acid, with B/Si atomic ratios of 0.2 and 0.5. Infrared spectra of PBS showed evidence of Si-O-B bonds at 880 cm-1, due to the incorporation of the crosslinker trigonal units of BO3 in the polymeric network. X ray diffraction analyses exhibited an amorphous character of the resulting polymer-derived ceramics obtained by pyrolysis up to 1000 °C under inert atmosphere. The C/SiBCO composites showed better thermal stability than the C/SiOC materials. In addition, good adhesion between the carbon fiber and the ceramic phase was observed by SEM microscopy147151Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Orientações legais aos cirurgiões-dentistas

O Objetivo deste trabalho foi realizar uma revisão de literatura com o intuito de estabelecer aos Cirurgiões-Dentistas, orientações legais para a elaboração de documentos clínicos que compõem o prontuário do paciente, desde a elaboração de uma adequada anamnese, confecção de atestados e receitas odontológicas, bem como o consentimento livre e informado. É necessário estabelecer com o paciente, uma relação de confiança e amizade, durante todo o tratamento, sempre informando e sendo transparente nas ações, além de manter um exame clínico detalhado e um prontuário completo atualizado e organizado

Experimental gel containing bioactive glass-ceramic to minimize the pulp damage caused by dental bleaching in rats

Objectives: This study evaluated if the use of a bioactive glass-ceramic-based gel, named Biosilicate (BS), before, after or mixed with bleaching gel, could influence the inflammation of the dental pulp tissue of rats’ molars undergoing dental bleaching with hydrogen peroxide (H2O2). Methodology: The upper molars of Wistar rats (Rattus norvegicus, albinus) were divided into Ble: bleached (35% H2O2, 30-min); Ble-BS: bleached and followed by BS-based gel application (20 min); BS-Ble: BS-based gel application and then bleaching; BS/7d-Ble: BS-based gel applications for 7 days and then bleaching; Ble+BS: blend of H2O2 with BS-based gel (1:1, 30-min); and control: placebo gel. After 2 and 30 days (n=10), the rats were euthanized for histological evaluation. The Kruskal-Wallis and Dunn statistical tests were performed (P<0.05). Results: At 2 days, the Ble and Ble-BS groups had significant alterations in the pulp tissue, with an area of necrosis. The groups with the application of BS-based gel before H2O2 had moderate inflammation and partial disorganization in the occlusal third of the coronary pulp and were significantly different from the Ble in the middle and cervical thirds (P<0.05). The most favorable results were observed in the Ble+BS, which was similar to the control in all thirds of the coronary pulp (P>0.05). At 30 days, the pulp tissue was organized and the bleached groups presented tertiary dentin deposition. The Ble group had the highest deposition of tertiary dentin, followed by the Ble-BS, and both were different from control (P<0.05). Conclusion: A single BS-based gel application beforehand or BS-based gel blended with a bleaching gel minimize the pulp damage induced by dental bleaching

Avaliação da altura facial inferior após expansão rápida da maxila

Clinicians have worried about the effect the rapid maxillay expansion (RME) might have on the lower face height (LFH). This study cephalometrically evaluated the LFH after RME, using two kinds of palatal expanders (Haas–G1 and Hyrax–nG2). The sample contained 93 lateral cephalograms from 31 brasilian patients, 15 females and 16 males; with a mean age of 13.2 years, and a range of 9-16 years. The cephalograms were taken before disjunction (T1), immediately after disjunction (T2) and after leveling (T3). G1 and G2 experienced similar changes in N-Me. S-Go didn’t change, but both groups showed gradative increases of values in T2 and T3. G1 and G2 displayed increased anterior and posterior LFH (Me-PP and GO-PP) in T2 and T3. After using both types of palatal expanders showed statistically significant increases in anterior and posterior LFH.O aumento que ocorre na altura facial inferior (AFI) após expansão rápida da maxila (ERM) preocupa os pesquisadores. Este estudo avaliou a AFI após ERM com dois disjuntores palatinos (Haas–G1 e Hyrax–G2). A amostra continha 93 telerradiografias em norma lateral, de 31 pacientes brasileiros, 15 do sexo feminino e 16 do masculino, e faixa etária entre 9 e 16 anos de idade (média=13a2m). Cada indivíduo foi radiografado pré-disjunção (T1), pós-disjunção (T2) e ao final do nivelamento (T3). A variável N-Me modificou de forma semelhante nos dois grupos; e a grandeza S-Go, não variou nos grupos, porém, seus valores aumentaram gradativamente nas fases T2 e T3. As grandezas PP-Me e PP-Go, mostraram, para G1 e G2, aumento da AFI anterior e posterior em T2 e T3. A AFI anterior e posterior aumentou estatisticamente com os dois aparelhos

Cartografia e diplomacia: usos geopolíticos da informação toponímica (1750-1850)

O artigo explora dimensões geopolíticas da toponímia, registradas em documentos cartográficos, desde as reformas empreendidas pelo consulado pombalino em meados do século XVIII, até às primeiras décadas do século XIX, em meio ao processo de afirmação do Estado imperial pós-colonial.This paper explores the geopolitical dimensions of toponymy as registered in cartographic documents dating from the reforms pushed through by the consulate of Marquis of Pombal in the mid 18th century to the early decades of the 19th century, as the post-colonial imperial State established itself

Convalescent plasma for COVID-19 in hospitalised patients : an open-label, randomised clinical trial

Background: The effects of convalescent plasma (CP) therapy in hospitalised patients with coronavirus disease 2019 (COVID-19) remain uncertain. This study investigates the effect of CP on clinical improvement in these patients. Methods: This is an investigator-initiated, randomised, parallel arm, open-label, superiority clinical trial. Patients were randomly (1:1) assigned to two infusions of CP plus standard of care (SOC) or SOC alone. The primary outcome was the proportion of patients with clinical improvement 28 days after enrolment. Results: A total of 160 (80 in each arm) patients (66.3% critically ill, 33.7% severely ill) completed the trial. The median (interquartile range (IQR)) age was 60.5 (48–68) years; 58.1% were male and the median (IQR) time from symptom onset to randomisation was 10 (8–12) days. Neutralising antibody titres >1:80 were present in 133 (83.1%) patients at baseline. The proportion of patients with clinical improvement on day 28 was 61.3% in the CP+SOC group and 65.0% in the SOC group (difference −3.7%, 95% CI −18.8–11.3%). The results were similar in the severe and critically ill subgroups. There was no significant difference between CP+SOC and SOC groups in pre-specified secondary outcomes, including 28-day mortality, days alive and free of respiratory support and duration of invasive ventilatory support. Inflammatory and other laboratory marker values on days 3, 7 and 14 were similar between groups. Conclusions: CP+SOC did not result in a higher proportion of clinical improvement on day 28 in hospitalised patients with COVID-19 compared to SOC alone

O manuscrito e o iconográfico em cartões-postais belicosos: da apologia cavalheiresca à contestação da Grande Guerra (1914-1918) na França

O trabalho analisa mensagens transmitidas por cartões-postais produzidos e circulados na França no contexto da Primeira Guerra Mundial (1914-1918), apresentando temática associada ao conflito. O objetivo é contrapor as mensagens iconográficas e textuais neles impressas à quelas que foram manuscritas por seus remetentes, de modo a evidenciar formas de expressão e percepções do conflito, conforme empregadas por civis e militares, em diferentes momentos de seu desenvolvimento.The paper analyzes messages conveyed by postcards produced and circulated in France during the First World War (1914-1918), with themes referring to the conflict. The intention is to compare the iconographic and textual messages printed with handwritten messages, to display forms of expression and perception of war, used by civilian and military on different occasions

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