Use of superabsorbent polymers to mitigate autogenous shrinkage in ultra-high performance concrete

Ultra-high performance concrete (UHPC) with low w/c-ratio is very prone to the formation of cracks due to autogenous shrinkage. These cracks can lead to a decreased durability of the concrete, resulting in higher maintenance and/or repair costs in the future. Superabsorbent polymers (SAPs) can be added to cementitious materials to provide internal curing and as a result reduce or even mitigate this autogenous shrinkage. In this paper, two different types of SAPs were added to cement paste to see their influence on mitigating autogenous shrinkage. One SAP is a commercially available SAP whereas the other SAP is especially developed within the framework of the LORCENIS project by the company ChemStream, with the aim to mitigate autogenous shrinkage and induce self-healing of cracks. The SAPs from ChemStream were based on a copolymerization of sodium vinyl sulfonate (SVS) with 2-acryloylamino-2-methyl-propane-1-sulfonate (NaAMPS) and contained 1.0 mol% N,N’-methylenebisacrylamide (MBA) with respect to the monomer as cross-linker. The commercial SAP from BASF was based on poly(acrylamide-co-acrylic acid). In case SAPs were used, an additional fixed amount of water was added to mitigate autogenous shrinkage. The amount of SAPs used was determined based on their swelling capacity in cement filtrate and in order to obtain the same workability as the reference mixture. The amount of SAPs needed was in the range of 0.2-0.26 m% of the cement weight. To see whether the size of the SAPs plays a role in the efficiency of mitigating autogenous shrinkage, two average particle sizes, namely 40 and 100 µm, were tested. With the used amount of SAPs, a reduction or even complete counteraction of autogenous shrinkage was observed for the cement pastes

Prevalence of treponema Spp. in endodontic retreatment-resistant periapical lesions

This study investigated the presence of the Treponema species in longstanding endodontic retreatment-resistant lesions of teeth with apical periodontitis, the association of this species with clinical/radiographic features, and the association among the different target species. Microbial samples of apical lesions were collected from twenty-five adult patients referred to endodontic surgery after unsuccessful root canal retreatment. Nested-PCR and conventional PCR were used for Treponema detection. Twenty-three periradicular tissue samples showed detectable levels of bacterial DNA. Treponema species were detected in 28% (7/25) of the cases. The most frequently detected species were T. socranskii (6/25), followed by T. maltophilum (3/25), T. amylovorum (3/25), T. lecithinolyticum (3/25), T. denticola (3/25), T. pectinovorum (2/25) and T. medium (2/25). T. vicentii was not detected in any sample. Positive statistical association was found between T. socranskii and T. denticola, and between T. maltophilum and T. lecithinolyticum. No association was detected between the presence of any target microorganism and the clinical or radiographic features. Treponema spp. are present, in a low percentage, in longstanding apical lesions from teeth with endodontic retreatment failure291CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES302575/2009-0sem informaçã

EVALUACIÓN DE LA FERTILIDAD DEL SUELO EN UNA PROPIEDAD AGRÍCOLA DEL PROYECTO DE DESARROLLO SOSTENIBLE PORTO SEGURO

O presente trabalho objetivou avaliar a fertilidade do solo na camada superficial em diferentes ecossistemas de produção para subsidiar o manejo sustentável do solo em uma propriedade agrícola familiar do Projeto de Desenvolvimento Sustentável Porto Seguro, Marabá-PA. Para a realização desse estudo as áreas foram divididas em quatro glebas ou agroecossistemas, denominados ao longo do trabalho de G1, G2, G3, G4. A G1 contém o plano de plantio de mandioca (Manihot esculenta Crantz), G2 a banana (Musa spp), G3 o Sistema Agroflorestal (SAF’s) e a G4 o feijão de corda (Vigna unguiculata (L.) Walp.). Foram coletadas amostras de solo de cada área, sendo que os solos dos cultivos em estudo apresentaram teores de pH, Al2+, P, Ca2+, Mg2+, H+, Al, SB, V%, N e MO abaixo dos valores ideais para manejo adequado das culturas. Os sistemas em cultivo nas áreas provocam alterações significativas na fertilidade do solo. As modificações podem estar ligadas às práticas de manejo do solo das culturas em estudo.The objective of this study was to evaluate the soil fertility in the topsoil in different production ecosystems to support the sustainable management of the soil in family farms of the Porto Seguro Sustainable Development Project, Marabá, state of Pará. For the execution of this experiment, the areas were divided into four tracts or agro-ecosystems, denominated throughout the work of G1, G2, G3, G4. The G1 is cropped with cassava (Manihot esculenta Crantz); G2, with banana (Musa spp), G3 with Agroforestry System (AFS), and G4 with cowpea (Vigna unguiculata (L.) Walp.). Soil samples were collected from each area, and the soils of the assessed crops showed levels of pH, Al2+, P, Ca2+, Mg2+, H+, Al, SB, V%, N, and OM below the ideal values for adequate crop management. The systems under cultivation in the areas cause significant changes in soil fertility. The modifications may be related to the soil management practices of the crops under study.El presente trabajo tuvo como objetivo evaluar la fertilidad del suelo en la capa superficial en diferentes ecosistemas de producción para apoyar el manejo sostenible del suelo en una granja familiar del Proyecto de Desarrollo Sostenible Porto Seguro, Marabá-PA. Para la realización de este estudio, las actividades se dividieron en cuatro parcelas o agroecosistemas, denominadas a lo largo del trabajo de G1, G2, G3, G4. G1 contiene el plan de siembra de yuca (Manihot esculenta Crantz), G2 el plátano (Musa spp), G3 el Sistema Agroforestal (SAF) y G4 el frijol (Vigna unguiculata (L.) Walp.). Se recolectaron muestras de suelo de cada área, siendo que los suelos de los cultivos estudiados presentaron niveles de pH, Al2+, P, Ca2+, Mg2+, H+, Al, SB, V%, N y OM por debajo de los valores ideales para el manejo adecuado del cultivo. Los sistemas de cultivo en las áreas causan cambios significativos en la fertilidad del suelo. Las modificaciones pueden estar vinculadas a las prácticas de manejo del suelo de los cultivos en estudio

Real-scale testing of the efficiency of self-healing concrete

After several years of research in the Magnel Laboratory (Belgium) to obtain concrete with self-healing properties, the most promising mechanisms were tested on a larger scale. Instead of small mortar samples with self-healing properties, real-scale self-healing concrete beams (150 mm × 250 mm × 3000 mm) were made and the efficiency of autonomous crack repair was evaluated over time after loading the beams in four-point bending. In addition to a reference beam without self-healing properties, a beam with encapsulated polyurethane and a beam containing superabsorbent polymers were investigated. While for the beam with polyurethane, crack repair is obtained as the healing agent is released as soon as cracks damage the embedded capsules, the superabsorbent polymers absorb water which intrudes into the cracks, immediately blocking the crack through swelling and later on by continued hydration and precipitation of calcite. The efficiency of both self-healing approaches was compared by measuring the reduction in water ingress into the cracks and by measuring the crack width reduction over time

Evaluation of cytotoxicity, antimicrobial activity and physicochemical properties of a calcium aluminate-based endodontic material

A calcium aluminate-based endodontic material, EndoBinder, has been developed in order to reduce MTA negative characteristics, preserving its biological properties and clinical applications. Objectives: The aim of this study was to evaluate the cytotoxicity, antimicrobial activity, pH, solubility and water sorption of EndoBinder and to compare them with those of white MTA (WMTA). Material and Methods: Cytotoxicity was assessed through a multiparametric analysis employing 3T3 cells. Antimicrobial activity against Enterococcus faecalis (ATCC 29212), Staphylococcus aureus. (ATCC 25923) and Candida albicans (ATCC 10556) was determined by the agar diffusion method. pH was measured at periods of 3, 24, 72 and 168 hours. Solubility and water sorption evaluation were performed following ISO requirements. Data were statistically analyzed by ANOVA and Tukey's test with a significance level of 5%. Results: EndoBinder and WMTA were non-cytotoxic in all tested periods and with the different cell viability parameters. There was no statistical differences between both materials (P>.05). All tested materials were inhibitory by direct contact against all microbial strains tested. EndoBinder and WMTA presented alkaline pH in all tested times with higher values of pH for WMTA (P.05). Conclusion: Under these experimental conditions, we concluded that the calcium aluminate-based endodontic material EndoBinder demonstrated suitable biological and physicochemical properties, so it can be suggested as a material of choice in root resorption, perforations and root-end filling221616

Evaluation of cytotoxicity, antimicrobial activity and physicochemical properties of a calcium aluminate-based endodontic material

A calcium aluminate-based endodontic material, EndoBinder, has been developed in order to reduce MTA negative characteristics, preserving its biological properties and clinical applications. Objectives: The aim of this study was to evaluate the cytotoxicity, antimicrobial activity, pH, solubility and water sorption of EndoBinder and to compare them with those of white MTA (WMTA). Material and Methods: Cytotoxicity was assessed through a multiparametric analysis employing 3T3 cells. Antimicrobial activity against Enterococcus faecalis (ATCC 29212), Staphylococcus aureus. (ATCC 25923) and Candida albicans (ATCC 10556) was determined by the agar diffusion method. pH was measured at periods of 3, 24, 72 and 168 hours. Solubility and water sorption evaluation were performed following ISO requirements. Data were statistically analyzed by ANOVA and Tukey`s test with a significance level of 5%. Results: EndoBinder and WMTA were non-cytotoxic in all tested periods and with the different cell viability parameters. There was no statistical differences between both materials (P>;.05). All tested materials were inhibitory by direct contact against all microbial strains tested. EndoBinder and WMTA presented alkaline pH in all tested times with higher values of pH for WMTA (

Assessmentof the quality of bee’s honey sold in the city of Manaus, Amazon / Avaliação da qualidade do mel de abelha comercializado na cidade de Manaus, Amazonas

O objetivo geral deste trabalho foi caracterizar os méis de abelhas produzidos e /ou comercializados em Manaus/AM, através de físico-químicas e microbiológicas e de testes de adulterantes. Os méis foram adquiridos em diferentes municípios do estado do Amazonas. As amostras foram levadas para o Laboratório de Alimentos e Nutrição, do Instituto de Pesquisas da Amazônia e foram avaliados quanto a adulteração, umidade, sólidos solúveis e pH, além da qualidade microbiológica de coliformes totais e Salmonella sp. Foi identificado que 40 % dos méis apresentaram adulteração. O teor de umidade variou entre 15 e 27 %. A concentração de sólidos solúveis totais variou entre 65 e 82 º Brix. O pH médio dos méis verdadeiros foi de 3,13 e dos méis adulterados foi de 3,10. Quanto a avaliação microbiológica, todos os méis apresentaram-se isentos de microrganismos como coliformes e salmonelas. Os méis de abelha avaliados apresentaram umidade elevada e pH levemente ácido, característico das abelhas melíponas, no entanto, algumas amostras ficaram fora da especificação legal do regulamento técnico. Todos os méis apresentaram excelente qualidade microbiológica

Diagnosis and treatment of late jaundice in late preterm and term newborns: An integrative literature review / Diagnóstico e tratamento da icterícia tardia em recém-nascidos prematuros tardios e a termo: Uma revisão integrativa de literatura

Although it is a common clinical condition in neonatology, jaundice must have an adequate diagnosis and an on-time treatment since the excess of bilirubin can lead to the development of kernicterus – that, in rare cases, can lead to neonatal death. This study aimed to identify which diagnostic methods and treatment of late jaundice in late preterm and term show greater relevance, efficacy, and safety. An integrative review was performed through SciELO, Pubmed, and Bireme databases, of publications between 2015 and 2020, using the descriptors "neonatal jaundice", "neonatal hyperbilirubinemia", "neonatal jaundice" and "neonatal hyperbilirubinemia".  After the articles extraction, they were stratified in a dataset, from which 17 articles that deal with the diagnosis and / or treatment of late preterm newborns and / or suitable for gestational age were selected and arranged in narrative and charts. It was possible to establish that although serum bilirubin testing is widely used, extracorporeal methods are a good option in the diagnosis of jaundice, with good accuracy, for which phototherapy is the main treatment. There are effective, safe, and low-cost alternatives for the diagnosis and treatment of neonatal jaundice, that work by minimizing the risks of complications

Evaluation of the natural fermentation process of native Amazon honey bees produced by breeders of the Sateré-Mawé ethnicity / Avaliação do processo de fermentação natural dos meis de abelhas nativas da Amazônia produzidos pelos criadores da etnia Sateré-Mawé

O trabalho teve como objetivo avaliar o processo de fermentação natural do mel de abelhas nativas da Amazônia produzido pelos criadores da etnia Sateré-Mawé, através do pH e acidez, associando-os a diferentes níveis de umidade. Foram coletadas seis amostras de méis de abelhas nativas da Amazônia. A umidade foi reduzida para 20 e 22% e os méis foram avaliados quando ao pH e acidez de 30, em 30 dias por até 180 dias. Os méis tiverem sua umidade reduzida por um desumidificador. Foram avaliadas a umidade, pH e acidez total. Os méis apresentaram comportamento esperado de pH e acidez ao longo do tempo de armazenamento. Houve decréscimo de pH e o aumento da acidez. Sobre o pH do mel das abelhas Meliponas apresentou resultados entre 4,33 e 4,61 e o mel de Scaptotrigona foi de 3,73 e 4,14, ao final do processo. A acidez foi de 1,26 e 1,75 % e 2,86 e 6,00 %, para os respectivos méis. Pode-se concluir que e a técnica de desumidificação do mel de abelhas nativas pode ser empregada com sucesso a fim de prolongar a vida útil do produto, bem como ampliar suas possibilidades de comercialização. A fermentação processou-se mais rapidamente nas alíquotas originais, devido ao elevado teor de umidade presente nas mesmas

Treatment outcomes of pulp revascularization in traumatized immature teeth using calcium hydroxide and 2% chlorhexidine gel as intracanal medication

Objective: Pulp revascularization is an effective treatment for immature necrotic teeth. Calcium hydroxide has been used in pulp revascularization as an intracanal medication due to its antimicrobial action and the non-exhibition of crown discoloration and cytotoxicity for stem cells from the apical papilla. Our study aimed to investigate the clinical success and quantitative radiographic changes of root development in immature traumatized teeth using calcium hydroxide plus 2% chlorhexidine gel as intracanal medication. Methodology: In this retrospective study, 16 patients were treated with a standardized pulp revascularization protocol. Calcium hydroxide and 2% chlorhexidine gel were manipulated in a 1:1 (v/v) ratio and inserted into root canals with Lentulo spirals (Dentsply Maillefer, Baillaigues, Switzerland). Patients were followed up for a period from 9 to 36 months for the evaluation of clinical and radiological data. Radiographic measurements of root length, root width, apical diameter, and MTA placement from the apex were quantified using software ImageJ. Wilcoxon test and t-test were used, according to nonparametric or parametric data, respectively, for changes over time in root length, root width, and apical diameter. Results: Fifteen teeth survived during the follow-up period (93.75%) and met the criteria for clinical success. Although the changes seem to be very small in many cases, significant increases in the average root length (14.28%, p<0.0001), root width (8.12%, p=0.0196), and decrease in apical diameter (48.37%, p=0.0007) were observed. MTA placement from the apex and age at the time of treatment was not significantly associated with the quantitative radiographic outcomes. Conclusions: Pulp revascularization in traumatized immature teeth treated with calcium hydroxide plus 2% chlorhexidine gel as intracanal medication had high success and survival rates, showing periodontal healing and resolution of signs and symptoms. However, concerning the continued root development, the outcomes can still be considered unpredictable