Publications by authors named "A K VISSER"

Aims: Concerns over population-level immunity have been heightened with each successive wave of COVID-19, prompting questions about whether it is primarily derived from vaccination efforts or from previous natural infections with the virus. We wished to determine the seroprevalence of SARS-CoV-2 antibodies among healthcare workers (HCWs) in Pretoria (Tshwane), South Africa, and to establish whether they were derived from vaccination or natural infection.

Methods: Serum samples were collected from HCWs during the fourth wave of COVID-19 between 1 December 2021 and 13 March 2022.

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Phosphorus (P) is pivotal for all organisms, yet its availability is, particularly in the marine habitat, limited. Natural, puff-shaped colonies of Trichodesmium, a genus of diazotrophic cyanobacteria abundant in the Red Sea, have been demonstrated to capture and centre dust particles. While this particle mining strategy is considered to help evade nutrient limitation, details behind the mechanism remain elusive.

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Aim: Masticatory dysfunction due to tooth loss is a potentially modifiable risk for mortality, but the pathway behind that remains to be investigated. This prospective study aimed to examine the role of diet and ageing in the associations between chewing capacity and long-term mortality.

Methods: Data were obtained from participants (aged ≥ 20) in the National Health Nutritional and Health Survey (NHANES 1999-2010, n = 22,900).

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Introduction: Resistance training (RT) is known to induce both peripheral and central adaptations, resulting in enhanced strength, sports performance, and health benefits. These adaptations are specific to the training stimuli. The acute cortical mechanisms of single sessions resistance exercise (RE) are not yet understood.

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Colonies of the N-fixing cyanobacterium spp. constitute a consortium with multiple microorganisms that collectively exert ecosystem-level influence on marine carbon and nitrogen cycling, shunting newly fixed nitrogen to low nitrogen systems, and exporting both carbon and nitrogen to the deep sea. Here we identify a seasonally recurrent association between puff colonies and amoebae through a two-year survey involving over 10 000 colonies in the Red Sea.

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