477 research outputs found

    Students’ perceptions of their experiences with online assessments during the Covid-19 pandemic

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    Abstract. Assessment is an essential element in teaching and learning, and the outbreak of the Covid-19 pandemic forced teachers and students to adapt this practice to the online modality. Yet, the existence of resources regarding online assessments is still limited. This study aims to explore how students perceived their experiences with online assessment during the pandemic, with a focus on their relationship with feedback, their emotions, and motivation. Qualitative semi-structured interviews were conducted with 10 participants who were within their last four years of basic education in the year 2020, with subsequent content analysis being applied. The results of this study indicate that students did not perceive major changes in the assessment methods applied by teachers. They did, however, perceive new challenges for their learning to emerge, and consequently made adaptations to their studying habits. Moreover, it was revealed that students received less feedback in the online modality, which had an impact on their emotional states and learning practices. Additionally, it was found that the pandemic and online learning contexts imposed new difficulties for students, whose emotions were negatively impacted, and whose motivation toward assessment tasks was significantly decreased. These factors led students to behaviors such as avoiding studying and engaging in dishonest academic practices. In conclusion, this study sheds light on topics relevant to online learning, online assessments, and students’ emotions and motivation regarding assessment, specifically in the context of emergency online learning

    Molecular and Phenotypic Characterization of Escherichia coli O26:H8 among Diarrheagenic E. coli O26 Strains Isolated in Brazil

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    Escherichia coli strains of serogroup O26 comprise two distinct groups of pathogens, characterized as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC). Among the several genes related to type III secretion system-secreted effector proteins, espK was found to be highly specific for EHEC O26:H11 and its stx-negative derivative strains isolated in European countries. E. coli O26 strains isolated in Brazil from infant diarrhea, foods, and the environment have consistently been shown to lack stx genes and are thus considered atypical EPEC. However, no further information related to their genetic background is known. Therefore, in this study, we aimed to discriminate and characterize these Brazilian O26 stx-negative strains by phenotypic, genetic, and biochemical approaches. Among 44 isolates confirmed to be O26 isolates, most displayed flagellar antigen H11 or H32. Out of the 13 nonmotile isolates, 2 tested positive for fliC(H11), and 11 were fliC(H8) positive. the identification of genetic markers showed that several O26:H11 and all O26:H8 strains tested positive for espK and could therefore be discriminated as EHEC derivatives. the presence of H8 among EHEC O26 and its stx-negative derivative isolates is described for the first time. the interaction of three isolates with polarized Caco-2 cells and with intestinal biopsy specimen fragments ex vivo confirmed the ability of the O26 strains analyzed to cause attaching-and-effacing (A/E) lesions. the O26:H32 strains, isolated mostly from meat, were considered nonvirulent. Knowledge of the virulence content of stx-negative O26 isolates within the same serotype helped to avoid misclassification of isolates, which certainly has important implications for public health surveillance.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Inst Butantan, Bacteriol Lab, São Paulo, BrazilFrench Food Safety Agcy, Maisons Alfort, FranceUniv Estadual Londrina, Dept Patol Geral, Ctr Ciencias Biomed, Londrina, Parana, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilCtr Univ Sao Camilo, São Paulo, BrazilBfR Fed Inst Risk Assessment, Natl Reference Lab Escherichia Coli, Berlin, GermanyUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilWeb of Scienc

    Different Assay Conditions for Detecting the Production and Release of Heat-Labile and Heat-Stable Toxins in Enterotoxigenic Escherichia coli Isolates

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    Enterotoxigenic Escherichia coli (ETEC) produce heat-labile (LT) and/or heat-stable enterotoxins (ST). Despite that, the mechanism of action of both toxins are well known, there is great controversy in the literature concerning the in vitro production and release of LT and, for ST, no major concerns have been discussed. Furthermore, the majority of published papers describe the use of only one or a few ETEC isolates to define the production and release of these toxins, which hinders the detection of ETEC by phenotypic approaches. Thus, the present study was undertaken to obtain a better understanding of ST and LT toxin production and release under laboratory conditions. Accordingly, a collection of 90 LT-, ST-, and ST/LT-producing ETEC isolates was used to determine a protocol for toxin production and release aimed at ETEC detection. for this, we used previously raised anti-LT antibodies and the anti-ST monoclonal and polyclonal antibodies described herein. the presence of bile salts and the use of certain antibiotics improved ETEC toxin production/release. Triton X-100, as chemical treatment, proved to be an alternative method for toxin release. Consequently, a common protocol that can increase the production and release of LT and ST toxins could facilitate and enhance the sensitivity of diagnostic tests for ETEC using the raised and described antibodies in the present work.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Butantan Inst, Bacteriol Lab, BR-05503900 São Paulo, BrazilSão Paulo Trop Med Inst, Seroepidemiol & Immunol Lab, BR-05403000 São Paulo, BrazilFleury Med & Hlth, BR-04344903 São Paulo, BrazilButantan Inst, Immunopathol Lab, BR-05503900 São Paulo, BrazilButantan Inst, Immunochem Lab, BR-05503900 São Paulo, BrazilAdolfo Lutz Inst, Bacteriol Sect, BR-01246000 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol, BR-04923062 São Paulo, SP, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol, BR-04923062 São Paulo, SP, BrazilWeb of Scienc

    Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology.

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    Trypanosoma cruzi, the flagellate protozoan agent of Chagas disease or American trypanosomiasis, is unable to synthesize sialic acids de novo. Mucins and trans-sialidase (TS) are substrate and enzyme, respectively, of the glycobiological system that scavenges sialic acid from the host in a crucial interplay for T. cruzi life cycle. The acquisition of the sialyl residue allows the parasite to avoid lysis by serum factors and to interact with the host cell. A major drawback to studying the sialylation kinetics and turnover of the trypomastigote glycoconjugates is the difficulty to identify and follow the recently acquired sialyl residues. To tackle this issue, we followed an unnatural sugar approach as bioorthogonal chemical reporters, where the use of azidosialyl residues allowed identifying the acquired sugar. Advanced microscopy techniques, together with biochemical methods, were used to study the trypomastigote membrane from its glycobiological perspective. Main sialyl acceptors were identified as mucins by biochemical procedures and protein markers. Together with determining their shedding and turnover rates, we also report that several membrane proteins, including TS and its substrates, both glycosylphosphatidylinositol-anchored proteins, are separately distributed on parasite surface and contained in different and highly stable membrane microdomains. Notably, labeling for α(1,3)Galactosyl residues only partially colocalize with sialylated mucins, indicating that two species of glycosylated mucins do exist, which are segregated at the parasite surface. Moreover, sialylated mucins were included in lipid-raft-domains, whereas TS molecules are not. The location of the surface-anchored TS resulted too far off as to be capable to sialylate mucins, a role played by the shed TS instead. Phosphatidylinositol-phospholipase-C activity is actually not present in trypomastigotes. Therefore, shedding of TS occurs via microvesicles instead of as a fully soluble form

    Trisomy 8, A Cytogenetic Abnormality In Myelodysplastic Syndromes, Is Constitutional Or Not?

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    Isolated trisomy 8 is not considered presumptive evidence of myelodysplastic syndrome (MDS) in cases without minimal morphological criteria. One reason given is that trisomy 8 (+8) can be found as a constitutional mosaicism (cT8M). We tried to clarify the incidence of cT8M in myeloid neoplasms, specifically in MDS, and the diagnostic value of isolated +8 in MDS. Twenty-two MDS and 10 other myeloid neoplasms carrying +8 were studied. Trisomy 8 was determined in peripheral blood by conventional cytogenetics (CC) and on granulocytes, CD3+ lymphocytes and oral mucosa cells by fluorescence in situ hybridization (FISH). In peripheral blood CC, +8 was seen in 4/32 patients. By FISH, only one patient with chronic myelomonocytic leukemia showed +8 in all cell samples and was interpreted as a cT8M. In our series +8 was acquired in all MDS. Probably, once discarded cT8M by FISH from CD3+ lymphocytes and non-hematological cells, +8 should be considered with enough evidence to MDS

    Erica: Prevalences Of Hypertension And Obesity In Brazilian Adolescents

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)To estimate the prevalence of arterial hypertension and obesity and the population attributable fraction of hypertension that is due to obesity in Brazilian adolescents. METHODS: Data from participants in the Brazilian Study of Cardiovascular Risks in Adolescents (ERICA), which was the first national school-based, cross-section study performed in Brazil were evaluated. The sample was divided into 32 geographical strata and clusters from 32 schools and classes, with regional and national representation. Obesity was classified using the body mass index according to age and sex. Arterial hypertension was defined when the average systolic or diastolic blood pressure was greater than or equal to the 95th percentile of the reference curve. Prevalences and 95% confidence intervals (95% CI) of arterial hypertension and obesity, both on a national basis and in the macro-regions of Brazil, were estimated by sex and age group, as were the fractions of hypertension attributable to obesity in the population. RESULTS: We evaluated 73,399 students, 55.4% female, with an average age of 14.7 years (SD = 1.6). The prevalence of hypertension was 9.6% (95% CI 9.0-10.3); with the lowest being in the North, 8.4% (95% CI 7.7-9.2) and Northeast regions, 8.4% (95% CI 7.6-9.2), and the highest being in the South, 12.5% (95% CI 11.0-14.2). The prevalence of obesity was 8.4% (95% CI 7.9-8.9), which was lower in the North region and higher in the South region. The prevalences of arterial hypertension and obesity were higher in males. Obese adolescents presented a higher prevalence of hypertension, 28.4% (95% CI 25.5-31.2), than overweight adolescents, 15.4% (95% CI 17.0-13.8), or eutrophic adolescents, 6.3% (95% CI 5.6-7.0). The fraction of hypertension attributable to obesity was 17.8%. CONCLUSIONS: ERICA was the first nationally representative Brazilian study providing prevalence estimates of hypertension in adolescents. Regional and sex differences were observed. The study indicates that the control of obesity would lower the prevalence of hypertension among Brazilian adolescents by 1/5.501Brazilian Department of Science and Technology at the Secretariat of Science and TechnologyStrategic Inputs of the Ministry of Health (Departamento de Ciencia e Tecnologia da Secretaria de Ciencia e Tecnologia e Insumos Estrategicos do Ministerio da Saude - Decit/SCTIE/MS)Health Fund Sector (Fundo Setorial de Saude - CT-health) at the Ministry of science, Technology and Innovation (Ministerio da Ciencia, Tecnologia e Inovacao - MCTI)FINEP [01090421]CNPq [2010/565037-2]hospital research incentive fund for Clinics in Porto Alegre (fundo de incentivo a Pesquisa do Hospital de Clinicas de Porto Alegre - HCPA) [405,009/FIPE-2012-7]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Inflammatory markers, tbars and vitamin E in class II and III obese patients before undergoing bariatric surgery

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    Background: Obesity and its comorbidities such as insulin resistance, endothelial dysfunction, hypertension, type 2 diabetes and atherosclerosis have been associated with chronic inflammation and oxidative stress. Weight loss with maintenance is not always possible. Bariatric surgery has been proved to be the only efficient method for weight reduction in patients with clinically severe obesity. It leads to significant weight loss and improvement and/or remission of comorbidities. On the other hand, considering that surgical intervention per se induces oxidative stress and inflammatory response, the objective of the present study was to verify if some inflammatory marker, TBARS and/or Vitamin E could be evaluated before gastric surgery. Methods: a quantitative cross-sectional study was carried out at Clinica Ana Rosa (Santo André, SP, Brazil). 100 obese patients (BMI ≥ 35-40 kg/m2) awaiting bariatric surgery were selected for this study. The control group included 29 individuals, BMI < 35 kg/m2, with or without associated comorbidities. The patients completed a structured interview. Weight, height, waist and hip circumferences were also collected. Blood was collected. Glucose (G), total cholesterol (TC), HDL cholesterol (HDLc), LDL cholesterol (LDLc), VLDL cholesterol (VLDLc), triglycerides (TG), high-sensitivity C-reactive protein (hs-CRP), vitamin E (VIT E), fibrinogen (FIB), IL-6 (human interleukin-6), TNF-alpha and thiobarbituric acid reactive substances (TBARS) were measured. Results: patients have shown increased serum levels of hs-CRP and FIB. In this study, class II and III obese patients awaiting bariatric surgery and the control group had lower than normal VIT E levels and no significant changes in TBARS levels were observed. Conclusions: excess weight and accumulated fat in subjects with severe obesity seem to be related to increased inflammatory response, therefore, our results reinforce the importance of evaluating inflammatory markers and VIT E in obese patients before bariatric surgery.Â

    Erica: Prevalence Of Metabolic Syndrome In Brazilian Adolescents

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)To determine the prevalence of metabolic syndrome and its components in Brazilian adolescents. METHODS: We evaluated 37,504 adolescents who were participants in the Study of Cardiovascular Risks in Adolescents (ERICA), a cross-sectional, school-based, national study. The adolescents, aged from 12 to 17 years, lived in cities with populations greater than 100,000 inhabitants. The sample was stratified and clustered into schools and classes. The criteria set out by the International Diabetes Federation were used to define metabolic syndrome. Prevalences of metabolic syndrome were estimated according to sex, age group, school type and nutritional status. RESULTS: Of the 37,504 adolescents who were evaluated: 50.2% were female; 54.3% were aged from 15 to 17 years, and 73.3% were from public schools. The prevalence of metabolic syndrome was 2.6% (95% CI 2.3-2.9), slightly higher in males and in those aged from 15 to 17 years in most macro-regions. The prevalence was the highest in residents from the South macro-region, in the younger female adolescents and in the older male adolescents. The prevalence was higher in public schools (2.8% [95% CI 2.4-3.2]), when compared with private schools (1.9% [95% CI 1.4-2.4]) and higher in obese adolescents when compared with nonobese ones. The most common combinations of components, referring to 3/4 of combinations, were: enlarged waist circumference (WC), low HDL-cholesterol (HDL-c) and high blood pressure; followed by enlarged WC, low HDL-c and high triglycerides; and enlarged WC, low HDL-c, high triglycerides and blood pressure. Low HDL was the second most frequent component, but the highest prevalence of metabolic syndrome (26.8%) was observed in the presence of high triglycerides. CONCLUSIONS: ERICA is the first Brazilian nation-wide study to present the prevalence of metabolic syndrome and describe the role of its components. Despite the prevalence of Metabolic Syndrome being low, the high prevalences of some components and participation of others in the syndrome composition shows the importance of early diagnosis of this changes, even if not grouped within the metabolic syndrome.501Department of Science and Technology of the Secretariat of Science, Technology and Strategic Inputs of the Ministry of Health (Decit/SCTIE/MS)Health Sectorial Fund (Fundo Setorial de Saude - CT-Saude) of the Ministry of Science, Technology and Innovation (MCTI)FINEP [01090421]CNPq [2010/565037-2]Research Incentive Fund of the Hospital de Clinicas de Porto Alegre - (Fundo de Incentivo a Pesquisa do Hospital de Clinicas de Porto Alegre - FIPE-HCPA) [405.009/2012-7]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
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