Avaliação de argamassas colantes por reometria rotacional

As argamassas colantes são produtos constituídos por areia natural ou artificial, ligantes (cimento) e aditivos químicos que cumprem uma função de adesivo para assentamento de revestimentos em pisos e paredes. Atualmente, a avaliação em campo sobre a mistura do produto é efetuada de forma empírica. O aplicador (pedreiro) determina, por meios de aspectos sensoriais, a facilidade ou a dificuldade de mistura, classificando a argamassa em pesada, leve, macia, de fácil ou de difícil mistura, etc. Porém, essas descrições são subjetivas e é difícil de mensurar quantitativamente a aplicabilidade do produto, além do que induzem a erros de avaliação, pois cada aplicador pode ter uma percepção diferente. O propósito deste trabalho foi medir, através da reometria rotacional, duas composições para avaliar o comportamento de mistura e reológico de forma quantitativa. Foram utilizadas duas argamassas colantes de mercado do tipo ACI (Argamassa Colante do Tipo I) e ACIII (Argamassa Colante do Tipo III), as quais foram submetidas a ensaios de reometria rotacional, variando-se o teor de água. Os resultados desta pesquisa demonstram que o tempo de mistura de 150 s é eficiente e suficiente para homogeneizar e estabilizar as argamassas testadas, e que a argamassa do tipo ACI apresenta maior dificuldade de mistura e resulta em uma suspensão com maior viscosidade e tensão de escoamento do que a argamassa ACIII. Este estudo mostra a aplicação e os resultados inéditos de reometria rotacional para avaliação do comportamento reológico de argamassas colantes. Essa transferência do conhecimento visa ampliar os horizontes sobre os comportamentos dos materiais de construção civil para melhorar o desempenho de aplicação e avaliação da argamassa no estado fresco

Autoantibodies against type I IFNs in patients with critical influenza pneumonia

In an international cohort of 279 patients with hypoxemic influenza pneumonia, we identified 13 patients (4.6%) with autoantibodies neutralizing IFN-alpha and/or -omega, which were previously reported to underlie 15% cases of life-threatening COVID-19 pneumonia and one third of severe adverse reactions to live-attenuated yellow fever vaccine. Autoantibodies neutralizing type I interferons (IFNs) can underlie critical COVID-19 pneumonia and yellow fever vaccine disease. We report here on 13 patients harboring autoantibodies neutralizing IFN-alpha 2 alone (five patients) or with IFN-omega (eight patients) from a cohort of 279 patients (4.7%) aged 6-73 yr with critical influenza pneumonia. Nine and four patients had antibodies neutralizing high and low concentrations, respectively, of IFN-alpha 2, and six and two patients had antibodies neutralizing high and low concentrations, respectively, of IFN-omega. The patients' autoantibodies increased influenza A virus replication in both A549 cells and reconstituted human airway epithelia. The prevalence of these antibodies was significantly higher than that in the general population for patients 70 yr of age (3.1 vs. 4.4%, P = 0.68). The risk of critical influenza was highest in patients with antibodies neutralizing high concentrations of both IFN-alpha 2 and IFN-omega (OR = 11.7, P = 1.3 x 10(-5)), especially those <70 yr old (OR = 139.9, P = 3.1 x 10(-10)). We also identified 10 patients in additional influenza patient cohorts. Autoantibodies neutralizing type I IFNs account for similar to 5% of cases of life-threatening influenza pneumonia in patients <70 yr old

Esophageal perforation in eosinophilic esophagitis: five cases in children

Background and study aims  Eosinophilic esophagitis (EoE) is a chronic immune disease with increasing incidence. It is clinically defined by symptoms of esophageal dysfunction and histologically by eosinophilic polynuclear cell infiltration of the esophageal mucosa. Symptoms are not specific and include gastroesophageal reflux disease (GERD), dysphagia, vomiting or dietary blockages. Chronic inflammation of the mucosa may lead to narrowing of the esophageal lumen responsible for impactions. Extraction procedures can be complicated by dissection and perforation. Rare spontaneous ruptures of the esophagus known as Boerhaave syndrome are also possible. We report five cases of esophageal perforation in children with EoE, three with spontaneous rupture and two after an endoscopic procedure. The evolution was favorable under medical treatment

Accuracy of prenatal ultrasound screening to identify fetuses infected by cytomegalovirus who will develop severe long-term sequelae

International audienceObjectives - To compare the ability of detailed routine ultrasound examination, performed without knowledge of maternal serology and fetal status, with that of targeted prenatal imaging performed in prenatal diagnostic units in cases of known fetal infection to identify cytomegalovirus (CMV)-infected fetuses that will develop long-term sequelae. Methods - All prenatal imaging reports were collected for 255 children with congenital CMV in a registered cohort between 2013 and 2017 (NCT01923636). All women had undergone detailed routine fetal ultrasound examination at 20-24 and 30-34 weeks as part of routine antenatal care. All cases of known fetal CMV infection had also undergone targeted prenatal ultrasound examination. Postnatal structured follow-up for up to 48 months of age involved clinical, audiological and neurological assessment, including Brunet-Lezine scoring. Long-term sequelae (> 12 months) were considered to be mild in cases with isolated unilateral hearing loss and/or vestibular disorders, and severe in cases with bilateral hearing loss and/or neurological sequelae. All imaging reports were analyzed retrospectively with the knowledge of congenital CMV infection, searching for reference to findings that were, or could have been, related to fetal infection. Findings were analyzed in relation to whether the cases were diagnosed with CMV in utero or only postnatally. Results - There were 237 children with complete follow-up data (> 12 months), for a median of 24 (range, 12-48) months. Of these, 30% (71/237) were diagnosed with CMV prenatally and 70% (166/237) were diagnosed within 3 weeks after birth. 72.5% (29/40) of children with long-term sequelae, including 74% (14/19) with severe long-term sequelae, were not identified in the prenatal period. Among those diagnosed prenatally, the sensitivity of prenatal imaging for predicting long-term sequelae and severe long-term sequelae was 91% and 100%, respectively, while, in the group diagnosed only postnatally, non-specific infection-related ultrasound findings had been reported without raising suspicion in 48% of cases with long-term sequelae and 64% of those with severe long-term sequelae. Conclusions - Routine detailed ultrasound examination in pregnancy is not an appropriate screening tool for congenital CMV infection that leads to long-term sequelae, in contrast with the high performance of targeted prenatal imaging in known cases of fetal infection. The non-specific nature of ultrasound features of CMV and their evolution, and a lack of awareness of caregivers about congenital CMV, are likely explanations. Awareness of the sonologist regarding congenital CMV and knowledge of the maternal serological status in the first trimester seem key to the performance of prenatal ultrasound. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd