An Investigation into the Trophic Magnification of Polychlorinated Biphenyls in the Lake Michigan Food Web

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants known to contribute to several adverse health conditions in humans including cancers and a suite of liver diseases. While there exist 209 unique PCB congeners, the World Health Organization has identified 12 that pose the greatest health risk to humans due to these congeners’ functional similarity to dioxins, another notoriously toxic class of contaminants. Along with methylmercury, PCBs are the primary drivers behind fish consumption advisories in the Great Lakes. These guidelines are informed primarily by surveys of contaminants in freshwater biota. However, the proliferation of invasive species, such as dreissenid mussels and round gobies, has dramatically restructured the food web and potentially the flow of contaminants in Lake Michigan. This research examined the relationship between food web structure and PCB concentrations in Lake Michigan biota. A second objective was to determine how invasive species have shifted trophic structure and what implications these alterations might have on contaminant transfer. Aquatic biota were sampled throughout the southern basin of Lake Michigan and analyzed for lipid content, WHO PCB congeners, and stable isotopes of nitrogen and carbon. Nitrogen isotopes were used to calculate trophic level, while carbon isotopes indicated the primary energy source of an organism. PCBs were extracted from lyophilized tissue using a microwave-assisted extraction technique and a hexane:acetone extraction solution. Crude extracts underwent silica and Florisil clean-up protocols to remove interferences prior to gas chromatography ¬– mass spectrometric determination. Stable isotope analysis revealed substantial shifts in trophic structure between 2002-2003 and 2019. Lake trout have significantly dropped in mean trophic level while slimy sculpin are relying more heavily on nearshore carbon relative to the 2002-2003 results. The PCB congeners observed in the highest concentrations in Lake Michigan biota in 2002-2003 closely paralleled those manufactured most commonly. Lipid content and PCB concentration showed a strong significant relationship. Following lipid correction, WHO congeners were shown to increase by a factor of 2.8 per trophic level. In addition, specific congeners appeared to magnify at different rates. Multiple regression analyses revealed that trophic level and lipid content were the best predictors for concentration of total WHO congeners as well as for congeners 105 and 118 specifically. Lake trout, deepwater sculpin, slimy sculpin, bloater chub, and lake whitefish all displayed elevated concentrations of WHO congeners relative to other species. Lake trout and yellow perch displayed an exponential relationship between total length and concentration of WHO congeners. Lake Michigan’s PCB trophic magnification effect in 2002-2003 was within range of that observed in other ecological systems. Possible explanations for the disparities between lakes are seasonal sampling biases, differences in primary productivity, and differential rates of PCB metabolism by fauna. For lake trout and yellow perch, changes in feeding behavior as they grow in size results in an increase of trophic level, thereby increasing PCB loads for larger members of these species. The trophic magnification factor and species-specific PCB results reported in this study enhance the scientific understanding of contaminant transfer in freshwater systems

Ego orientation is related to doping likelihood via sport supplement use and sport supplement beliefs

A growing body of evidence suggests sport supplement use is positively related to doping likelihood, both directly and indirectly via beliefs that sport supplements are effective for improving performance. However, it is unclear what leads an athlete to use sport supplements and whether such factors play a role in the supplement-beliefs-doping relationship. To address this issue, we examined whether motivational goal orientations were related to doping likelihood directly and indirectly via sport supplement use and sport supplement beliefs. Competitive athletes (  = 362, 39% female, mean ± SD; age = 23.6 ± 10.3 years, hours per week training = 5.8 ± 2.1, years competing = 5.8 ± 5.4) from a range of sports (e.g., athletics, soccer, weightlifting) completed an online survey measuring task and ego goal orientation, sport supplement use, sport supplement beliefs, and doping likelihood. Results indicated that ego orientation, but not task orientation, was indirectly related to doping likelihood via sport supplement use and sport supplement beliefs. This suggests that athletes who are ego oriented are more likely to use supplements, believe supplements are effective, and dope. These data suggest that researchers should consider ego goal orientations when interpreting relationships between sport supplement use and doping likelihood

Toxins induce ‘malaise’ behaviour in the honeybee (Apis mellifera)

To avoid poisoning and death when toxins are ingested, the body responds with a suite of physiological detoxification mechanisms accompanied by behaviours that in mammals often include vomiting, nausea, and lethargy. Few studies have characterised whether insects exhibit characteristic ‘malaise-like’ behaviours in response to intoxication. Here, we used the honeybee to investigate how intoxication produced by injection or ingestion with three toxins with different pharmacological modes of action quinine, amygdalin, and lithium chloride affected behaviour. We found that toxin-induced changes in behaviour were best characterised by more time spent grooming. Bees also had difficulty performing the righting reflex and exhibited specific toxin-induced behaviours such as abdomen dragging and curling up. The expression of these behaviours also depended on whether a toxin had been injected or ingested. When toxins were ingested, they were least 10 times less concentrated in the haemolymph than in the ingested food, suggesting that their absorption through the gut is strongly regulated. Our data show that bees exhibit changes in behaviour that are characteristic of ‘malaise’ and suggest that physiological signalling of toxicosis is accomplished by multiple post-ingestive pathways in animals

The Development of a Menthol Solution for Use during Sport and Exercise

Menthol mouth-swilling has been shown to improve performance across differing exercise modalities, yet no work has been conducted to ascertain the preferred concentration of menthol within a swill. Colour has also been shown to influence psychophysiological outcomes, and may influence the efficacy of ergogenic aids. We conducted two experiments: one to ascertain preferred menthol concentration (0.005–0.105% menthol), the second to assess colour preference (Light Blue, Dark Blue, Light Green, Dark Green, Red). Participants rated swills for Smell, Taste, Freshness, Mouth Feel and Irritation (plus Appearance in the second trial) via 15 cm Visual Analogue Scales (VAS), having swilled and expectorated 25 mL of fluid. Both trials employed a crossover design, with tasting order assigned by Latin squares. Differences were assessed for statistical significance (p < 0.05) using one-way repeated measures ANOVAs. Standardised mean differences ±90% confidence intervals were calculated to assess the magnitude of any observed differences. No significant differences were found between concentrations for total VAS score, but higher concentrations demonstrated a greater number of small effects. Similarly, no significant differences between colours were found. Small effects were found when Light Green was compared to Dark Green and Red. Effects were trivial when Light Green was compared to Light Blue (0.05 ± 0.20) and Dark Blue (0.19 ± 0.32). We recommend athletes employ a Light Green or Light Blue 0.1% menthol mouth-swill

Evaluation of Hydrogen Storage in Metal Organic Frameworks by Bridged Hydrogen Spillover

Hydrogen has the potential to be the next energy carrier. The ability to use hydrogen in fuel cell technologies depends largely on the ability to store hydrogen efficiently. Metal-Organic Frameworks (MOFs) belong to an interesting set of materials that consists of porous channels and have been shown to carry potential for hydrogen storage when added to metal catalysts. MOFs alone show no potential to store hydrogen, but when added to metal catalyst they can exhibit a spillover effect to increase hydrogen storage capacity. The key critical issues with MOFs are to validate the promises that MOFs can provide with spillover, since spillover intricately linked to more standard H2 storage mechanisms. The current project focuses on the synthesis of Isoreticular Metal Organic Framework-8 (IRMOF-8) added to platinum on Activated Carbon (AC) and bridged together with sucrose to enhance the spillover effect. In order to reach hydrogen storage goals, a method must be proven to have enough capacity for the adsorption/resorption (reversibility) at ambient and 120 bar reasonable pressures. With the tremendous interest in spillover materials for hydrogen storage, NREL and DOE have dedicated resources to synthesize specific materials and to develop, perform, and validate the requisite measurements

Dietary supplement use is related to doping intention via doping attitudes, subjective norms, and perceived behavioural control.

The use of dietary supplements (e.g., caffeine, creatine, dietary nitrate) has shown to be related to the intention to dope (e.g., amphetamines, anabolic steroids, erythropoietin). In this study, we integrated elements of the theory of planned behaviour to better understand the relationship between dietary supplement use and doping intention. Specifically, we tested whether dietary supplement use is indirectly related to doping via doping attitudes, doping subjective norms, and doping perceived behavioural control. Competitive athletes (N = 443; 46 % female, age = 27.0 ± 8.6 years old, years competing = 8.3 ± 3.5) completed measures of dietary supplement use, doping attitudes, doping subjective norms, doping perceived behavioural control, and doping intention. Parallel mediation analysis indicated that dietary supplement use was not directly related to doping intention, but instead was indirectly related via doping attitudes (effect size = 0.15), doping subjective norms (effect size = 0.17), and doping perceived behavioural control (effect size = 0.15). Contrast analyses reported no differences between each indirect effect. Our results suggest that athletes who use dietary supplements report stronger intentions to dope, which is related to more favourable doping attitudes, a greater social pressure to dope, and a perceived ease in which to dope

A Study to Inform the Design of a National Multicentre Randomised Controlled Trial to Evaluate If Reducing Serum Phosphate to Normal Levels Improves Clinical Outcomes including Mortality, Cardiovascular Events, Bone Pain, or Fracture in Patients on Dialysis

Background. Retrospective, observational studies link high phosphate with mortality in dialysis patients. This generates research hypotheses but does not establish “cause-and-effect.” A large randomised controlled trial (RCT) of about 3000 patients randomised 50 : 50 to lower or higher phosphate ranges is required to answer the key question: does reducing phosphate levels improve clinical outcomes? Whether such a trial is technically possible is unknown; therefore, a study is necessary to inform the design and conduct of a future, definitive trial. Methodology. Dual centre prospective parallel group study: 100 dialysis patients randomized to lower (phosphate target 0.8 to 1.4 mmol/L) or higher range group (1.8 to 2.4 mmol/L). Non-calcium-containing phosphate binders and questionnaires will be used to achieve target phosphate. Primary endpoint: percentage successfully titrated to required range and percentage maintained in these groups over the maintenance period. Secondary endpoints: consent rate, drop-out rates, and cardiovascular events. Discussion. This study will inform design of a large definitive trial of the effect of phosphate on mortality and cardiovascular events in dialysis patients. If phosphate lowering improves outcomes, we would be reassured of the validity of this clinical practice. If, on the other hand, there is no improvement, a reassessment of resource allocation to therapies proven to improve outcomes will result. Trial Registration Number. This trial is registered with ISRCTN registration number ISRCTN24741445

Acceptability of hygiene, face covering and social distancing interventions to prevent exacerbations in people living with airways diseases

Interventions to prevent the spread of SARS-CoV-2 have been associated with substantial reductions in exacerbations of airways diseases, likely through reduced transmission of other respiratory viruses. We surveyed 4442 people with airways disease (asthma=3627, bronchiectasis=258, chronic obstructive pulmonary disease=557) to gauge attitudes and intentions towards continuing such measures after the COVID-19 pandemic. 47% intended to continue wearing a face mask in indoor public spaces, and 61% thought everyone should be required to do so during the ‘influenza season. Women, those with bronchiectasis, and older people were generally more cautious. Respiratory virus infection control measures should be considered in clinical guidelines and public health recommendations