714 research outputs found

    Effect Of Salivary Contamination At Different Steps Of The Bonding Process On The Microleakage Around Class V Restorations

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    This study aimed to investigate the influence of the moment of salivary contamination during the bonding procedure (before or after acid conditioning) on the microleakage around composite resin restorations. Sixty bovine incisors received two Class V preparations (one with dentin margins and other with enamel margins). Teeth were randomly assigned into three, groups (n-20): 1) control (not contaminated); 2) salivary contamination before etching with 34% phosphoric acid; and, 3) salivary contamination after acid etching. Cavities were restored using Prime & Bond NT (Dentsply) adhesive system and TPH Spectrum (Dentsply) composite according to manufacturer instructions. Teeth were thermocycled (500x, 5-55°C, 60s/bath), immersed in 2% methylenee blue buffered solution (pH 7.0), and sectioned into two halves. Three examiners measured the extent of dye penetration or dentin and enamel margins in a stereoscope microscope, using four representative scores. Statistical analysis were performed with Kruskal-Wallis/Wilcoxon tests (α-5%). The results showed that enamel and dentin margins did not present significant differences (p>0.05). However, significantly higher dye penetration was observed on substrates etched and further contaminated with saliva. It was concluded that salivary contamination after acid etching increases the microleakage around composite resin restorations, especially at dentin margins. However, acid etching subsequent to the contamination can avoid negative effects on restorations margins.62314451449Van Meerbeek, B., Van Landuyt, K., De Munck, J., Hashimoto, M., Peumans, M., Lambrechts, P., Technique -sensitivity of contemporary adhesives (2005) Dent Mater J, 24, pp. 1-13Civelek, A., Ersoy, M., L'Hotelier, E., Soyman, M., Say, E.C., Polymerization shrinkage and microleakage in Class II cavities of various resin composites (2003) Oper Dent, 28, pp. 635-641Besnault, C., Attal, J.P., Influence of a simulated oral environment on microleakage of two adhesive systems in Class II composite restorations (2002) J Dent, 30, pp. 1-6Spencer, P., Wang, Y., Bohaty, B., Interfacial chemistry of moisture-aged class II composite restorations (2006) J Biomed Mater Res B Appl Biomater, 77, pp. 234-240Direct and indirect restorative materials (2003) J Am Dent Assoc, 134, pp. 463-472. , Council on Scientific Affairs ADASoldani, F., Foley, J., An assessment of rubber dam usage amongst specialists in paediatric dentistry practising within the UK (2007) Int J Paediatr Dent, 17, pp. 50-56Fernandes, A.S., Rodrigues, S., Singhal, K., Murthi, M.S., Assessment of chair side techniques for composite resin restoration - a survey (2003) Indian J Dent Res, 14, pp. 47-56Taskonak, B., Sertgoz, A., Shear bond strengths of saliva contaminated 'one-bottle' adhesives (2002) J Oral Rehabil, 29, pp. 559-564Eiriksson, S.O., Pereira, P.N., Swift Jr., E.J., Heymann, H.O., Sigurdsson, A., Effects of saliva contamination on resin-resin bond strength (2004) Dent Mater, 20, pp. 37-44Hiraishi, N., Kitasako, Y., Nikaido, T., Nomura, S., Burrow, M.F., Tagami, J., Effect of artificial saliva contamination on pH value change and dentin bond strength (2003) Dent Mater, 19, pp. 429-434Park, J.W., Lee, K.C., The influence of salivary contamination on shear bond strength of dentin adhesive systems (2004) Oper Dent, 29, pp. 437-442Yoo, H.M., Oh, T.S., Pereira, P.N., Effect of saliva contamination on the microshear bond strength of one-step self-etching adhesive systems to dentin (2006) Oper Dent, 31, pp. 127-134Hitmi, L., Attal, J.P., Degrange, M., Influence of the time-point of salivary contamination on dentin shear bond strength of 3 dentin adhesive systems (1999) J Adhes Dent, 1, pp. 219-232Reis, A.F., Giannini, M., Kavaguchi, A., Soares, C.J., Line, S.R., Comparison of microtensile bond strength to enamel and dentin of human, bovine, and porcine teeth (2004) J Adhes Dent, 6, pp. 117-121Eiriksson, S.O., Pereira, P.N., Swift, E.J., Heymann, H.O., Sigurdsson, A., Effects of blood contamination on resin-resin bond strength (2004) Dent Mater, 20, pp. 184-190Toledano, M., Osorio, R., Ceballos, L., Fuentes, M.V., Fernandes, C.A., Tay, F.R., Microtensile bond strength of several adhesive systems to different dentin depths (2003) Am J Dent, 16, pp. 292-29

    COVID-19 Screening Score for Patients without Acute Respiratory Symptoms Undergoing Emergency Medical Procedures in Indonesia

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    To rule out coronavirus disease–2019 (COVID-19) in patients scheduled to undergo emergency medical procedures, SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR) must be performed. In developing countries, the use of SARS-CoV-2 RT-PCR has been limited by its unavailability and long processing time. Hence, a quick screening score to predict COVID-19 may help healthcare practitioners determine which patients without acute respiratory symptoms can safely undergo an emergency medical procedure. We conducted a cross-sectional study of adult patients without acute respiratory symptoms who were admitted to the emergency department and underwent an emergency medical procedure within 24 hours after admittance. We collected baseline demographic data, COVID-19 screening variables, and SARS-CoV-2 RT-PCR as the gold standard for COVID-19 diagnosis. Bivariate and multivariate analyses were performed, and a scoring system was developed using statistically significant variables from the multivariate analysis. With data from 357 patients, multivariate backward stepwise logistic regression analysis resulted in two significant COVID-19 predictors: the presence of SARS-CoV-2–IgM antibody (adjusted odds ratio [aOR]: 7.02 [95% CI: 1.49–32.96]) and typical chest x-ray (aOR: 23.21 [95% CI: 10.01–53.78]). A scoring system was developed using these predictors with an area under the receiver operating characteristic curve of 0.71 (95% CI: 0.64–0.78). For a cutoff point of $ 2, the scoring system showed 42.5% sensitivity and 97.1% specificity but had poor calibration (Hosmer-Lemeshow test P value, 0.001). We believe that the development of this COVID-19 quick screening score may be helpful in a resource-limited clinical setting, but its moderate discrimination and poor calibration hinder its use as a replacement for the SARS-CoV-2 RT-PCR test for COVID-19 screening.</p

    Nanomaterials for Advancing the Health Immunosensor

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    Nanotechnology has exerted a significant impact in the development of biosensors allowing more sensible analytical methods. In health applications, the main challenge of the immunoassay is to reach the suitable limit of detection, recognizing different analytes in complex samples like whole blood, serum, urine, and other biological fluids. Different nanomaterials, including metallic, silica and magnetic nanoparticles, quantum dots, carbon nanotubes, and graphene, have been applied, mainly to improve charge electron transfer, catalytic activity, amount of immobilized biomolecules, low-background current, signal-to-noise ratio that consequently increase the sensitivity of immunosensors. Given the great impact of nanotechnology, this chapter intends to discuss new aspects of nanomaterials relating to immunosensor advancement

    Optomechanical characterization of acoustic modes in a mirror

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    We present an experimental study of the internal mechanical vibration modes of a mirror. We determine the frequency repartition of acoustic resonances via a spectral analysis of the Brownian motion of the mirror, and the spatial profile of the acoustic modes by monitoring their mechanical response to a resonant radiation pressure force swept across the mirror surface. We have applied this technique to mirrors with cylindrical and plano-convex geometries, and compared the experimental results to theoretical predictions. We have in particular observed the gaussian modes predicted for plano-convex mirrors.Comment: 8 pages, 8 figures, RevTe

    Modelling the impact of school reopening and contact tracing strategies on Covid-19 dynamics in different epidemiologic settings in Brazil

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    This study was funded by the Brazilian National Council for Scientific and Technological Development (CNPq) [grant number 402834/2020-8]. MEB received a technological and industrial scholarship from CNPq [grant number 315854/2020-0]. LSF received a master's scholarship from Coordination for the Improvement of Higher Education Personnel (CAPES) [finance code 001]. SP was supported by São Paulo Research Foundation (FAPESP) [grant number 2018/24037-4]. AMB received a technological and industrial scholarship from CNPq [grant number 402834/2020-8]. CF was supported by FAPESP [grant numbers 2019/26310-2 and 2017/26770-8]. MQMR received a postdoctoral scholarship from CAPES [grant number 305269/2020-8]. LMS received a technological and industrial scholarship from CNPq [grant number 315866/2020-9]. RSK has been supported by CNPq [grant number 312378/2019-0]. PIP has been supported by CNPq [grant number 313055/2020-3]. JAFD-F has been supported by CNPq productivity fellowship and the National Institutes for Science and Technology in Ecology, Evolution and Biodiversity Conservation (INCT-EEC), supported by MCTIC/CNPq [grant number 465610/2014-5] and Goiás Research Foundation (FAPEG) [grant number 201810267000023]. RAK has been supported by CNPq [grant number 311832/2017-2] and FAPESP [grant number 2016/01343-7]. CMT has been supported by CNPq productivity fellowship and the National Institute for Health Technology Assessment (IATS) [grant number 465518/2014-1].Peer reviewedPublisher PD

    Tentativas De Suicídio E Suicídios Na Atenção Pré-hospitalar

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    To characterize suicide attempts and suicides in a city in Northwestern Parana State, attended in the pre-hospital care. Methods: Descriptive, cross-sectional study, performed with pre-hospital care records to 257 victims of suicide and suicide attempt, in the period in 2005 to 2012, through two-dimensional analysis by chi-square. Results: There were 180 attempted suicides and 76 suicides. The age ranged 13-93 years, mean 33.5 ± 15.1 years and most prevalent in young male population. The events concentrated on the months of spring and summer, in the urban area. The use of biting object was the most used method, followed by poisoning and precipitation high places. Conclusion: To know the characteristics, methods and aggravating factors provide subsidies for the implementation of prevention measures. © 2016, Editora Cientifica Nacional Ltda. All rights reserved.65323123

    Svestka's Research: Then and Now

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    Zdenek Svestka's research work influenced many fields of solar physics, especially in the area of flare research. In this article I take five of the areas that particularly interested him and assess them in a "then and now" style. His insights in each case were quite sound, although of course in the modern era we have learned things that he could not readily have envisioned. His own views about his research life have been published recently in this journal, to which he contributed so much, and his memoir contains much additional scientific and personal information (Svestka, 2010).Comment: Invited review for "Solar and Stellar Flares," a conference in honour of Prof. Zden\v{e}k \v{S}vestka, Prague, June 23-27, 2014. This is a contribution to a Topical Issue in Solar Physics, based on the presentations at this meeting (Editors Lyndsay Fletcher and Petr Heinzel

    Linkage and association studies identify a novel locus for Alzheimer disease at 7q36 in a Dutch population-based sample

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    We obtained conclusive linkage of Alzheimer disease (AD) with a candidate region of 19.7 cM at 7q36 in an extended multiplex family, family 1270, ascertained in a population-based study of early-onset AD in the northern Netherlands. Single-nucleotide polymorphism and haplotype association analyses of a Dutch patient-control sample further supported the linkage at 7q36. In addition, we identified a shared haplotype at 7q36 between family 1270 and three of six multiplex AD-affected families from the same geographical region, which is indicative of a founder effect and defines a priority region of 9.3 cM. Mutation analysis of coding exons of 29 candidate genes identified one linked synonymous mutation, g.38030G-->C in exon 10, that affected codon 626 of the PAX transactivation domain interacting protein gene (PAXIP1). It remains to be determined whether PAXIP1 has a functional role in the expression of AD in family 1270 or whether another mutation at this locus explains the observed linkage and sharing. Together, our linkage data from the informative family 1270 and the association data in the population-based early-onset AD patient-control sample strongly support the identification of a novel AD locus at 7q36 and re-emphasize the genetic heterogeneity of AD
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