7 research outputs found

    Impact of hemodialysis on P-wave amplitude, duration, and dispersion

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    Atrial fibrillation (AF) is a frequent arrhythmia in patients undergoing hemodialysis (HD). P wave duration (PWdu) and P wave dispersion (PWdi) have been shown to be predictors of emerging AF in different clinical conditions. We sought to study the impact of HD on PWdu, PWdi, and P wave amplitude in a cohort of patients undergoing HD. Seventeen patients (8 men, 31±10 years) were studied. Echocardiography parameters, the sum of the amplitude of P waves in all 12 ECG leads (SP), mean PWdu, and PWdi, along with a host of other parameters (body weight, heart rate, electrolytes and hemoglobin/hematochrit) were measured 1/2h, before and after, HD. SP increased (11.8±3.9 vs 15.3±4.0 mm, p = 0.004), mean PWdu remained stable (82.7±11.1 vs 81.6±10.5 ms, p = 0.606), PWdi decreased (51.7±19.1 vs 41.7±19.1 ms, p = 0.03), and left atrial dimension decreased (37.96±3.90 vs 30.62±3.38 mm, p = 0.0001), after HD. The change in PWdi correlated with fluid removed by HD (r = -0.55, p = 0.022). Re-measurements of P-wave parameters in a random group of 11 of the 17 patients revealed augmented SP (p = 0.01), and stable mean PWdu (p = 0.36), and PWdi (p = 0.31), after HD. Fluid removed by HD leads to an increase in SP, a stable mean PWdu, and decrease (or stability on re-measurement in a subgroup of patients) in PWdi. Stability of PWdu may be due to the effects of augmentation of the P-wave amplitude and the reduction of the left atrial volume, cancelling each other. Variability of PWdi may stem from the occasional impossibility to measure PWdu (or measure it correctly) in minute P-waves in certain ECG leads, which in turn profoundly affects the PWdi

    Trial Evaluation Protocol Research Learning Communities (The RLC programme)

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    The Research Learning Communities programme aims to improve Literacy and Mathematics outcomes of Children in Need (CIN) and Looked After Children (LAC), by supporting Subject Leads, Designated Teachers and year 5 and 6 teachers in primary schools to further develop and implement research-informed teaching strategies. The RLC programme will be developed and delivered by the School of Education in Durham University, between October 2021 and May 2022. Although the programme was previously delivered to schools and was evaluated, it is the first time that it will be focusing on supporting teachers to develop evidence-based teaching strategies specifically for CIN/LAC. To do so, trained facilitators will develop and deliver a series of six workshops, preceded by an introductory session, and closed by a final ‘moving forward’ session, with Subject Leads and Designated Teachers across 240 primary schools in 6 local authorities (LAs). To evaluate the RLC programme, this study will conduct an impact evaluation, an implementation and process evaluation, and a cost analysis using a mixed methods approach. In summary: ‱ The impact evaluation will involve a randomised control trial (RCT) of year 6 pupils’ CIN/LAC KS2 scores in Literacy and Mathematics, supplied by the National Pupil Database (NPD); and an assessment of teachers’ knowledge of academic/action research, attitudes towards the use of research, use of academic/action research in practice, and implementation of improved teaching practices for CIN/LAC, assessed through a pre- and post- teacher questionnaire. ‱ The implementation and process evaluation (IPE) will also draw on the pre- and post- teacher questionnaires, and, in addition, include a series of case studies, (consisting of interviews with school leaders and teachers in intervention and control schools) and observations of RLC workshops. ‱ The cost analysis will collect data on delivery team costs for the implementation of the programme, teacher cover costs to attend RLC workshops and sessions, programme costs (such as costs incurred by virtual schools to recruit schools into the programme), as well as costs for facilities, equipment, and materials, among others. This data will be gathered by the delivery team and through teachers in the teacher questionnaire. Note: Since recruitment for the programme is still ongoing at the time of writing, this trial protocol has been developed based on an estimated number of schools and local authorities provided by the WWCSC. We have also estimated the number of teachers and CIN/LAC per school based on publicly available data. An updated protocol will be published after school recruitment has been finalised

    New Approach in Dealing with the Non-Negativity of the Conditional Variance in the Estimation of GARCH Model

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    In this paper, we propose a robust estimation of the conditional variance of the GARCH(1,1) model with respect to the non-negativity constraint against parameter sign. Conditions of second order stationary as well as the existence of moments are given for the new relaxed GARCH(1,1) model whose conditional variance is estimated deriving firstly the unconstrained estimation of the conditional variance from the GARCH(1,1) state space model, then, the robustification is implemented by the Kalman filter outcomes via density function truncation method. The GARCH(1,1) parameters are subsequently estimated by the quasi-maximum likelihood, using the simultaneous perturbation stochastic approximation, based, first, on the Gaussian distribution and, second, on the Student-t distribution. The proposed approach seems to be efficient in improving the accuracy of the quasi-maximum likelihood estimation of GARCH model parameters, in particular, with a prior boundedness information on volatilit

    Modelling the active SARS-CoV-2 helicase complex as a basis for structure-based inhibitor design

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    The RNA helicase (non-structural protein 13, NSP13) of SARS-CoV-2 is essential for viral replication, and it is highly conserved among the coronaviridae family, thus a prominent drug target to treat COVID-19. We present here structural models and dynamics of the helicase in complex with its native substrates based on thorough analysis of homologous sequences and existing experimental structures. We performed and analysed microseconds of molecular dynamics (MD) simulations, and our model provides valuable insights to the binding of the ATP and ssRNA at the atomic level. We identify the principal motions characterising the enzyme and highlight the effect of the natural substrates on this dynamics. Furthermore, allosteric binding sites are suggested by our pocket analysis. Our obtained structural and dynamical insights are important for subsequent studies of the catalytic function and for the development of specific inhibitors at our characterised binding pockets for this promising COVID-19 drug target

    Comparative Investigation of Chemical Constituents of Kernels, Leaves, Husk, and Bark of Juglans regia L., Using HPLC-DAD-ESI-MS/MS Analysis and Evaluation of Their Antioxidant, Antidiabetic, and Anti-Inflammatory Activities

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    Leaves, husk, kernels, and bark methanolic extracts of Juglans regia L. were tested for their in vitro antidiabetic, anti-inflammatory, and antioxidant activities. For these purposes, α-amylase and α-glucosidase were used as the main enzymes to evaluate antidiabetic activities. Moreover, lipoxidase and tyrosinase activities were tested to estimate anti-inflammatory properties. Antioxidant properties of Juglans regia L., extracts were determined using three different assays. Leaves extract has an important radical scavenging activity and a-amylase inhibition. Similarly, husk extracts showed high total phenolic content (306.36 ± 4.74 mg gallic acid equivalent/g dry extract) with an important α-amylase inhibition (IC50 = 75.42 ± 0.99 µg/mL). Kernels exhibit significant tyrosinase (IC50 = 51.38 ± 0.81 µg/mL) correlated with antioxidant activities (p < 0.05). Husk and bark extracts also showed strong anti-lipoxidase activities with IC50 equal to 29.48 ± 0.28 and 28.58 ± 0.35 µg/mL, respectively. HPLC-DAD-ESI-MS/MS analysis highlights the phenolic profile of methanolic extracts of Juglans regia L. plant parts. The identified polyphenols were known for their antioxidant, antidiabetic (dicaffeoyl-quinic acid glycoside in kernels), and anti-inflammatory (3,4-dihydroxybenzoic acid in leaves) activities. Further investigations are needed to determine molecular mechanisms involved in these effects as well as to study the properties of the main identified compounds
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