Evaluation of C4b as an adjunct marker in symptomatic RT-PCR negative Covid-19 cases

IntroductionDetecting low viral load has been a challenge in this pandemic, which has led to its escalated transmission. Complement activation has been implicated in pathogenesis of Covid-19 infection. Thus, evaluation of complement activation in suspected Covid-19 infection may help to detect infection and limit false negative cases thus limiting transmission of infection. We speculate that measuring C4b, produced from an activated complement system due to the presence of Covid-19 may help in its detection, even when the viral titers are low.MethodsPlasma C4b levels of symptomatic RT-PCR positive patients (cases, n = 40); symptomatic RT-PCR negative patients (n = 35) and asymptomatic RT-PCR negative controls (n = 40) were evaluated. Plasma C5b-9, IL-6, D-dimer and C1-Inhibitor (C1-INH) were also measured in cases and controls. ELISA kits were used for all measurements. Statistical analyses were carried out using Stata, version 12 (Stata Corp., Texas, USA).ResultsC4b levels were found to be significantly increased in RT-PCR positive patients as compared to asymptomatic RT-PCR negative controls. RT-PCR negative but symptomatic patients still showed increased C4b levels. The significantly higher levels of C4b in cases with a cut-off value of ≥ 116 ng/ml with optimum sensitivity and specificity of 80% and 52% respectively is indicative of its possible use as an adjunct marker. Increased levels of D-dimer, IL6, along with decreased levels of C1-INH were found in cases compared to controls. Whereas, C5b-9 levels were not significantly raised in cases.ConclusionsThe results of our study suggests that plasma C4b may help to detect infection in false negative cases of RT-PCR that escape detection owing to low viral load. However, to confirm it a large-scale study is needed.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12291-022-01033-z.     

儿童与父母冲突--亲子互动研究的一个重要课题

目前亲子互动研究成为一个非常重要的课题。父母冲突作为考察亲子互动关系的一个重要变量,逐渐成为研究者关注的重要问题。尽管20世纪70年代以来,国外已从某些角度揭示了父母冲突与儿童发展的关系,并在一定程度上探讨了父母冲突对儿童的影响。但我国目前还没有系统的儿童与父母冲突的研究。因此,从我国的具体情况入手探讨亲子冲突对丰富和发展儿童心理学的基本理论,全面了解并有效促进儿童发展具有重要的理论和实践意义。     

Exploring the uses of mobile phones to support informal learning

This paper explores how a group of undergraduate students in the United Arab Emirates (UAE) use their mobile phones to perform informal learning activities related to the content of their courses outside the classroom. The paper also addresses the usefulness of informal learning activities to support students’ learning. The study adopts an exploratory case study design and uses multiple methods of data collection including questionnaires, interviews and diary entries. Main findings suggest that students performed informal learning activities mostly from home, interacting mainly with classmates. It also shows that students were in control of their informal learning activities without teachers’ input. However, it was found that students used only a limited number of applications but these were considered useful to their learning. The paper contributes to a discussion of the implications of training and instructor support to help students to take more advantage of mobile phone applications to support informal learning. Recommendations for further research are discussed.     

Robust simultaneous fault detection and control for a class of nonlinear stochastic switched delay systems under asynchronous switching

This paper concerns the simultaneous fault detection and control (SFDC) problem for a class of nonlinear stochastic switched systems with time-varying state delay and parameter uncertainties. The switching signal of detector/controller unit (DCU) is assumed to be with switching delay, which results in the asynchronous switching between the subsystems and DCU. By constructing a switching strategy depending on the state and switching delays, new sufficient conditions expressed by a set of linear matrix inequalities (LMIs) is derived to design DCU gains. This problem is formulated as an H_∞ optimization problem and both mean square exponential stability and fault detection of augmented system are considered. A numerical example is finally exploited to verify the effectiveness and potential of the achieved scheme.     

中国足协处罚权研究

中国足协的处罚权是其参与体育治理的重要手段,相较于法定性强、形态有限的行政处罚, 更具专业性和针对性。为了保障其良性运转,维护相对人的诉讼权利,司法权的适度介入已成为理论界的共识。但我国传统的行政主体理论不能回应这种社会公权力发展的现实需要,并对其作出合理解释。因此,亟需重构我国的行政主体理论,赋予中国足协行政主体地位,构建司法审查规则,即法院审查足协处罚权时应当遵循仲裁优先原则、穷尽内部救济原则、法律审查原则;在审查范围上,除了审查足协处罚行为,还应当附带审查处罚规则。