Seroprevalence of SARS-CoV-2 in Croatian solid-organ transplant recipients     

Anna Mrzljak   eljka Jurekovi&#x;  Jadranka Pavi i&#x;-&#x;ari&#x;  Vladimir Stevanovi&#x;  Irena Tabain   eljka Hru&#x;kar  Danko Mikuli&#x;  Ljubo Barbi&#x;  Tatjana Vilibi&#x;-avlek 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2021,31(3)

IntroductionThe data on the coronavirus disease (COVID-19) in solid-organ transplant recipients (SOTRs) in Croatia is unknown. The aim of this study was to analyze the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Croatian SOTRs.Materials and methodsFrom 7 September to 27 November 2020 (beginning of the second COVID-19 pandemic wave), a cross-sectional screening for COVID-19 was performed in the adult outpatient liver (LTRs; N = 280) and kidney transplant recipients (KTRs; N = 232). Serum samples were initially tested for SARS-CoV-2 IgG antibodies using a commercial enzyme-linked immunosorbent assay (ELISA; Vircell Microbiologists, Granada, Spain). All positive samples were confirmed using a virus neutralization test (VNT). Data on risk exposure and COVID-19 related symptoms were collected using a questionnaire.ResultsThe transplanted cohort’s seroprevalence detected by ELISA and VNT was 20.1% and 3.1%, respectively. Neutralizing (NT) antibodies developed in 15.6% of anti-SARS-CoV-2 ELISA IgG positive SOTRs. The difference in seropositivity rates between LTRs and KTRs was not statistically significant (ELISA 21.1% vs. 19.0%, P = 0.554; VNT 3.6% vs. 2.6%, P = 0.082). Overall VNT positivity rates were higher in patients who reported participation in large community events (5.9% vs. 1.0%; P = 0.027) as well as in patients who reported COVID-19 related symptoms in the past six months. In addition, symptomatic VNT positive patients showed significantly higher (P = 0.031) NT antibody titers (median 128, interquartile range (IQR) = 32-128) compared to asymptomatic patients (median 16, IQR = 16-48).ConclusionsThis study showed that 15.6% of anti-SARS-CoV-2 ELISA positive Croatian SOTRs developed NT antibodies indicating protective immunity. Further studies are needed to determine the dynamic of NT antibodies and COVID-19 immunity duration in immunocompromised populations such as LTRs and KTRs.  相似文献   

Assessment validity and learning analytics as prerequisites for ensuring student-centred learning design     

Blaženka Divjak  Barbi Svetec  Damir Horvat  Nikola Kadoić 《British journal of educational technology : journal of the Council for Educational Technology》2023,54(1):313-334

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Seroprevalence of SARS-CoV-2 infection among children in Children’s Hospital Zagreb during the initial and second wave of COVID-19 pandemic in Croatia     

Jasna Lenicek Krleza  Renata Zrinski Topic  Vladimir Stevanovic  Amarela Lukic-Grlic  Irena Tabain  Zrinjka Misak  Goran Roic  Bernard Kaic  Dijana Mayer  Zeljka Hruskar  Ljubo Barbic  Tatjana Vilibic-Cavlek 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2021,31(2)

IntroductionThe study aimed to investigate the prevalence and titres of anti-SARS-CoV-2 antibodies in children treated at the Children’s Hospital Zagreb in the first and the second wave of the COVID-19 pandemic. Statistical significance of difference at two time points was done to determine how restrictive epidemiological measures and exposure of children to COVID-19 infection affect this prevalence in different age groups.Materials and methodsAt the first time point (13th to 29th May 2020), 240 samples and in second time point (24th October to 23rd November 2020), 308 serum samples were tested for anti-SARS-CoV-2 antibodies by enzyme-linked immunosorbent assay (ELISA) and electrochemiluminescence immunoassay (ECLIA). Confirmation of results and titre determination was done using virus micro-neutralization test. Subjects were divided according to gender, age and epidemiological history.ResultsSeroprevalence of anti-SARS-CoV-2 antibodies differs significantly in two time points (P = 0.010). In first time point 2.9% of seropositive children were determined and in second time point 8.4%. Statistically significant difference (P = 0.007) of seroprevalence between two time points was found only in a group of children aged 11-19 years. At the first time point, all seropositive children were asymptomatic with titre < 8. At the second time point, 69.2% seropositive children were asymptomatic with titre ≥ 8.ConclusionsThe prevalence of anti-SARS-CoV-2 antibodies was significantly lower at the first time point than at the second time point. Values of virus micro-neutralization test showed that low titre in asymptomatic children was not protective at the first time point but in second time point all seropositive children had protective titre of anti-SARS-CoV-2 antibodies.  相似文献   

Self-controlled learning benefits: exploring contributions of self-efficacy and intrinsic motivation via path analysis     

Diane M. Ste-Marie  Michael J. Carter  Barbi Law  Kelly Vertes  Victoria Smith 《Journal of sports sciences》2016,34(17):1650-1656

Research has shown learning advantages for self-controlled practice contexts relative to yoked (i.e., experimenter-imposed) contexts; yet, explanations for this phenomenon remain relatively untested. We examined, via path analysis, whether self-efficacy and intrinsic motivation are important constructs for explaining self-controlled learning benefits. The path model was created using theory-based and empirically supported relationships to examine causal links between these psychological constructs and physical performance. We hypothesised that self-efficacy and intrinsic motivation would have greater predictive power for learning under self-controlled compared to yoked conditions. Participants learned double-mini trampoline progressions, and measures of physical performance, self-efficacy and intrinsic motivation were collected over two practice days and a delayed retention day. The self-controlled group (M = 2.04, SD = .98) completed significantly more skill progressions in retention than their yoked counterparts (M = 1.3, SD = .65). The path model displayed adequate fit, and similar significant path coefficients were found for both groups wherein each variable was predominantly predicted by its preceding time point (e.g., self-efficacy time 1 predicts self-efficacy time 2). Interestingly, the model was not moderated by group; thus, failing to support the hypothesis that self-efficacy and intrinsic motivation have greater predictive power for learning under self-controlled relative to yoked conditions.  相似文献   

A survey of good practice in control education     

J. A. Rossiter  B. Pasik-Duncan  Sebastian Dormido  Ljubo Vlacic  Bryn Jones  Richard Murray 《European Journal of Engineering Education》2018,43(6):801-823

This paper gives a focussed summary of good practice taken primarily from engineers who are responsible for teaching topics related to systems and control. This engineering specialisation allows the paper to give some degree of focus in the discussions around laboratories, software and assessment, although naturally many of the conclusions are generic. A key intention is to provide a summary document or survey paper which can be used by academics as a start point in studies of what is effective in the discipline. It is also hoped that such a summary will be useful to engineering institutions in drawing together and disseminating open access resources that are freely available to the community at large.  相似文献