A Two-Phase, Single Cohort Study of COVID-19 Antibody Sera-Surveillance

Objective: The infectious corona virus, COVID-19 has high case mortality in those whom suffer with severe symptoms requiring hospitalisation. A major problem associated with COVID-19 is the spread of infection by a-symptomatic carriers, or those with mild symptoms. We aim to determine the antibody prevalence in a professional Welsh cohort and begin to explore the longevity of COVID-19 antibodies. Methods: 739 Cardiff Metropolitan University staff members took part in an observational study to determine the prevalence of COVID-19 antibodies in a two-phase, single cohort study. All participants were tested for IgM and IgG antibodies against COVID-19 using a lateral flow detection assay. Venous blood samples from positive participants and a randomly selected negative population were collected to confirm antibody titre, using two gold standard immunoassays, carried out independently by the Specialist Virology Centre, UHW. Results: 3.65% of the population tested positive for antibodies against COVID-19, with a higher prevalence seen in male participants (5% vs. 2.73% of females). In addition to gender, both pre-existing asthma and age were key determinants in antibody positivity. 78.26% retained antibodies at the 3 months follow up test. 36.36% of females lost antibody positivity between the 3 - and 6 - month time points compared with 8.3% of males. Lateral flow antibody testing was shown to have 96% sensitivity and 95% specificity compared with standard tests. Conclusion: We conclude that prevalence of COVID-19 antibodies is evident in the asymptomatic population, and in 78.26% of those initially antibody positive prevails at approximately 6 months from perceived time of exposure. Males are 4 times more likely to retain antibodies for longer than females

Association between Aortic Stiffness and Cerebral Pulsatility is Modestly Influenced by Augmentation Index

Central Pulse Pressure (CPP) and Aortic Pulse Wave Velocity (aPWV) share a positive relationship with cerebral pulsatility and are associated with cerebrovascular disorders including stroke. Our aim was to examine the influence of Augmentation Index (AIx) upon this relationship, first by using a cross sectional design across a wide range of CPP and aPWV in healthy individuals and second, following administration of Glyceryl Trinitrate (GTN) to acutely change AIx. We measured CPP, aPWV, AIx and Middle Cerebral Artery Pulsatility Index (MCAPI) in 99 healthy individuals (54 females). In all individuals, after accounting for the effect of age and gender, MCAPI shared an independent inverse relationship with AIx (β = −0.515, R2 = 0.109; p = 0.001), and a positive relationship with CPP (β = 0.570, R2 = 0.093; p = 0.003) but not aPWV (p > 0.05). GTN was administered to 25 of these participants (14 females). Following GTN, AIx75 decreased in all participants relative to baseline (12 ± 19 to 5 ± 16%; p = 0.0001). In the 20 min following GTN administration, CPP shared a positive relationship with MCAPI (β = 0.305, R2 = 0.042; p = 0.002) while AIx, adjusted for heart rate (AIx75), shared an inverse relationship with MCAPI (β = −0.320, R2 = 0.019; p = 0.031). These findings indicate that the positive relationship between CPP and MCAPI may be somewhat modified by AIx. This suggests that an increased AIx may weakly attenuate increases in MCAPI that are associated with aortic stiffening in a healthy population at rest, but also following acute reductions in AIx75 after administration of GTN

The southwest Indian Ocean Bathymetric Compilation (swIOBC)

We present a comprehensive regional bathymetric data compilation for the southwest Indian Ocean (swIOBC) covering the area from 4°S to 40°S and 20°E to 45°E with a spatial resolution of 250 m. For this, we used multibeam and singlebeam data as well as data from global bathymetric data compilations. We generated the swIOBC using an iterative approach of manual data cleaning and gridding, accounting for different data qualities and seamless integration of all different kinds of data. In comparison to existing bathymetric charts of this region the new swIOBC benefits from nearly four times as many data-constrained grid cells and a higher resolution, and thus reveals formerly unseen seabed features. In the central Mozambique Basin a surprising variety of landscapes were discovered. They document a deep reaching influence of the Mozambique Current eddies. Details of the N-S trending Zambezi Channel could be imaged in the central Mozambique Basin