Wave propagation in stereo-lithographical (STL) bone replicas at oblique incidence

Comparisons between predictions of a Biot-Allard model allowing for angle-dependent elasticity and angle-and-porosity dependent tortuosity and transmission data obtained at normal incidence on water-saturated replica bones are extended to oblique incidence. The model includes two parameters which are adjusted for best fit at normal incidence. Using the same parameter values, it is found that predictions of the variation of transmitted waveforms with angle through two types of bone replica are in reasonable agreement with data despite the fact that scattering is not included in the theory

Humidity cell tests for the prediction of acid rock drainage

This paper presents a study of various geochemical humidity-style weathering tests that were carried out on waste mine rock from Avoca, County Wicklow, Ireland. The aim of this paper is to present data that demonstrate some of the geochemical controls on weathering rates together with release rates from laboratory testwork. These data are used to determine the applicability of various interpretations of humidity cell data for prediction of acid rock drainage. Furthermore, within this context the paper offers opinion on common questions related to the use of such tests: should humidity cells be aerated? How long should the test be run for? Is pre-treatment of the samples required? Is inoculation of the samples with iron and sulfur oxidising microbes required? And should these tests really be considered to be accelerated weathering tests

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

Microbial Lag Phase can be Indicative of, or Independent From, Cellular Stress

Measures of microbial growth, used as indicators of cellular stress, are sometimes quantified at a single time-point. In reality, these measurements are compound representations of length of lag, exponential growth-rate, and other factors. Here, we investigate whether length of lag phase can act as a proxy for stress, using a number of model systems (Aspergillus penicillioides; Bacillus subtilis; Escherichia coli; Eurotium amstelodami, E. echinulatum, E. halophilicum, and E. repens; Mrakia frigida; Saccharomyces cerevisiae; Xerochrysium xerophilum; Xeromyces bisporus) exposed to mechanistically distinct types of cellular stress including low water activity, other solute-induced stresses, and dehydration-rehydration cycles. Lag phase was neither proportional to germination rate for X. bisporus (FRR3443) in glycerol-supplemented media (r2 = 0.012), nor to exponential growth-rates for other microbes. In some cases, growth-rates varied greatly with stressor concentration even when lag remained constant. By contrast, there were strong correlations for B. subtilis in media supplemented with polyethylene-glycol 6000 or 600 (r2 = 0.925 and 0.961), and for other microbial species. We also analysed data from independent studies of food-spoilage fungi under glycerol stress (Aspergillus aculeatinus and A. sclerotiicarbonarius); mesophilic/psychrotolerant bacteria under diverse, solute-induced stresses (Brochothrix thermosphacta, Enterococcus faecalis, Pseudomonas fluorescens, Salmonella typhimurium, Staphylococcus aureus); and fungal enzymes under acid-stress (Terfezia claveryi lipoxygenase and Agaricus bisporus tyrosinase). These datasets also exhibited diversity, with some strong- and moderate correlations between length of lag and exponential growth-rates; and sometimes none. In conclusion, lag phase is not a reliable measure of stress because length of lag and growth-rate inhibition are sometimes highly correlated, and sometimes not at all

Dark sectors 2016 Workshop: community report

This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years