THE RELATIONSHIP BETWEEN MAXIMAL STRENGTH AND PLYOMETRIC ABILITY IN RUGBY PLAYERS

This study examined the role of maximal strength in plyometric exercise performance in twenty strength-trained rugby players. Players’ maximal leg strength was assessed using a 3 or 5RM barbell back squat strength testing procedure. Plyometric ability was assessed using ground contact times and the reactive strength index variable during depth jumps from a variety of box heights (12, 36 and 51cm) performed on a force plate. The data indicated a strong positive relationship between strength levels and plyometric ability. Stronger subjects achieved better reactive strength indices than weaker counterparts and are more capable of performing depth jumps at higher intensities. Stronger athletes may benefit more from fast SSC plyometric training than their weaker counterparts

The SARS-CoV-2 viral load in COVID-19 patients is lower on face mask filters than on nasopharyngeal swabs.

Face masks and personal respirators are used to curb the transmission of SARS-CoV-2 in respiratory droplets; filters embedded in some personal protective equipment could be used as a non-invasive sample source for applications, including at-home testing, but information is needed about whether filters are suited to capture viral particles for SARS-CoV-2 detection. In this study, we generated inactivated virus-laden aerosols of 0.3-2 microns in diameter (0.9 µm mean diameter by mass) and dispersed the aerosolized viral particles onto electrostatic face mask filters. The limit of detection for inactivated coronaviruses SARS-CoV-2 and HCoV-NL63 extracted from filters was between 10 to 100 copies/filter for both viruses. Testing for SARS-CoV-2, using face mask filters and nasopharyngeal swabs collected from hospitalized COVID-19-patients, showed that filter samples offered reduced sensitivity (8.5% compared to nasopharyngeal swabs). The low concordance of SARS-CoV-2 detection between filters and nasopharyngeal swabs indicated that number of viral particles collected on the face mask filter was below the limit of detection for all patients but those with the highest viral loads. This indicated face masks are unsuitable to replace diagnostic nasopharyngeal swabs in COVID-19 diagnosis. The ability to detect nucleic acids on face mask filters may, however, find other uses worth future investigation

Superspreaders drive the largest outbreaks of hospital onset COVID-19 infections.

SARS-CoV-2 is notable both for its rapid spread, and for the heterogeneity of its patterns of transmission, with multiple published incidences of superspreading behaviour. Here, we applied a novel network reconstruction algorithm to infer patterns of viral transmission occurring between patients and health care workers (HCWs) in the largest clusters of COVID-19 infection identified during the first wave of the epidemic at Cambridge University Hospitals NHS Foundation Trust, UK. Based upon dates of individuals reporting symptoms, recorded individual locations, and viral genome sequence data, we show an uneven pattern of transmission between individuals, with patients being much more likely to be infected by other patients than by HCWs. Further, the data were consistent with a pattern of superspreading, whereby 21% of individuals caused 80% of transmission events. Our study provides a detailed retrospective analysis of nosocomial SARS-CoV-2 transmission, and sheds light on the need for intensive and pervasive infection control procedures

An in vivo ratio control mechanism for phospholipid homeostasis: evidence from lipidomic studies

While it is widely accepted that the lipid composition of eukaryotic membranes is under homeostatic control, the mechanisms through which cells sense lipid composition are still the subject of debate. It has been postulated that membrane curvature elastic energy is the membrane property that is regulated by cells, and that lipid composition is maintained by a ratio control function derived from the concentrations of type II and type 0 lipids, weighted appropriately. We assess this proposal by seeking a signature of ratio control in quantified lipid composition data obtained by electrospray ionization mass spectrometry from over 40 independent asynchronous cell populations. Our approach revealed the existence of a universal ‘pivot’ lipid, which marks the boundary between type 0 lipids and type II lipids, and which is invariant between different cell types or cells grown under different conditions. The presence of such a pivot species is a distinctive signature of the operation in vivo, in human cell lines, of a control function that is consistent with the hypothesis that membrane elastic energy is homeostatically controlled

Composition and origin of sediments at DSDP Site 54-424

The sediments recovered on Deep Sea Drilling Project Leg 54 appear to be mixtures of the normal pelagic sediments of the area and hydrothermally produced manganese and iron phases. The latter are mineralogically and chemically very similar to phases recovered from surficial sampling of the mounds. The hydrothermal nontronite which is approximately 15 meters thick in the three holes is essentially free of carbonate or detrital contaminants. The basal sediments are similar to the carbonate oozes presently being deposited in the region, but are enriched in Mn and Fe. This enrichment appears to be the result of hydrothermal deposition that took place at or near the spreading center and may not be associated with the mounds formation. Three different hypotheses for the formation of the nontronite layer and the mounds deposits are considered. An initial deposition of a widespread nontronite layer and subsequent diapiric-like movement of the layer into carbonates could account for the observed stratigraphy; however, if this be correct, analogous deposits should be present in other DSDP sites. The second hypothesis - replacement of the normal sediments by nontronite - may be feasible, but the high purity of the nontronite requires dissolution and removal of refractory elements. The third hypothesis, metal deposition in an advancing oxidation gradient, is compatible with submersible observations of the mounds; however, it can account only for the high purity of the nontronite by very rapid deposition of the hydrothermal phases

A metagenomic prospective cohort study on gut microbiome composition and clinical infection in small bowel transplantation

ABSTRACTTwo-thirds of small-bowel transplantation (SBT) recipients develop bacteremia, with the majority of infections occurring within 3 months post-transplant. Sepsis-related mortality occurs in 31% of patients and is commonly caused by bacteria of gut origin, which are thought to translocate across the implanted organ. Serial post-transplant surveillance endoscopies provide an opportunity to study whether the composition of the ileal and colonic microbiota can predict the emergence as well as the pathogen of subsequent clinical infections in the SBT patient population. Five participants serially underwent aspiration of ileal and colonic bowel effluents at transplantation and during follow-up endoscopy either until death or for up to 3 months post-SBT. We performed whole-metagenome sequencing (WMS) of 40 bowel effluent samples and compared the results with clinical infection episodes. Microbiome composition was concordant between participants and timepoint-matched ileal and colonic samples. Four out of five (4/5) participants had clinically significant infections thought to be of gut origin. Bacterial translocation from the gut was observed in 3/5 patients with bacterial infectious etiologies. In all three cases, the pathogens had demonstrably colonized the gut between 1–10 days prior to invasive clinical infection. Recipients with better outcomes received donor grafts with higher alpha diversity. There was an increase in the number of antimicrobial resistance genes associated with longer hospital stay for all participants. This metagenomic study provides preliminary evidence to support the pathogen translocation hypothesis of gut-origin sepsis in the SBT cohort. Ileal and colonic microbiome compositions were concordant; therefore, fecal metagenomic analysis could be a useful surveillance tool for impeding infection with specific gut-residing pathogens