Experiences from the ARGOS user group nuclear emergency exercise.

The Accident Reporting and Guiding Operational System (ARGOS) is a decision support system used to assist in the Emergency Preparedness and Response (EPR) to nuclear and radiological incidents. The ARGOS user group has been formed that is made up of government agencies across many countries that have a role in EPR to nuclear and radiological incidents. In 2020, a desktop exercise was organised for the members of the ARGOS user group. The exercise involved two hypothetical accidents at different times on the same date, namely a radiological release from a floating nuclear power plant (NPP) off the Norwegian coast and from the Loviisa NPP in Finland. The objectives of the exercise were to train and increase knowledge of the ARGOS system, to perform a comparison of model outputs, and to compare the recommendations of protective actions. In the case of the floating NPP the source term was provided, while in the Loviisa NPP scenario the participants were required to provide their own source term based on a description of the accident. The results on radiological consequences based on dispersion modelling, protective actions, source terms and dispersion modelling settings were collected from participants. A comparison was made between each of these reported aspects. In general, it was found that there was general agreement between the results for the floating nuclear power plant scenario in the sense of plume direction and extent, while in the case of the Loviisa NPP scenario, there was much greater variation, with the difference in source term estimates between the participants being an influencing factor. The participants acknowledged that taking part in an exercise of this nature increased their knowledge and understanding about using decision support tools such as ARGOS in planning and responding to nuclear and radiological emergencies.

AMPlify: attentive deep learning model for discovery of novel antimicrobial peptides effective against WHO priority pathogens.

BACKGROUND: Antibiotic resistance is a growing global health concern prompting researchers to seek alternatives to conventional antibiotics. Antimicrobial peptides (AMPs) are attracting attention again as therapeutic agents with promising utility in this domain, and using in silico methods to discover novel AMPs is a strategy that is gaining interest. Such methods can sift through large volumes of candidate sequences and reduce lab screening costs. RESULTS: Here we introduce AMPlify, an attentive deep learning model for AMP prediction, and demonstrate its utility in prioritizing peptide sequences derived from the Rana [Lithobates] catesbeiana (bullfrog) genome. We tested the bioactivity of our predicted peptides against a panel of bacterial species, including representatives from the World Health Organization's priority pathogens list. Four of our novel AMPs were active against multiple species of bacteria, including a multi-drug resistant isolate of carbapenemase-producing Escherichia coli. CONCLUSIONS: We demonstrate the utility of deep learning based tools like AMPlify in our fight against antibiotic resistance. We expect such tools to play a significant role in discovering novel candidates of peptide-based alternatives to classical antibiotics.

A Comparison of Collaborative Testing and Alternative Test-Taking Methods on Content Retention in Baccalaureate Nursing Students.

ABSTRACT: Nursing faculty look for ways to promote the retention of content so that students can build on that content and apply it to nursing practice. A study was designed to determine differences in content retention between testing collaboratively, which involves students taking an exam collectively within a small group, using an individual notecard, and including written rationale for test answers during collaborative testing. Students who tested collaboratively had significantly higher long-term content retention than students who tested with the other methods.

The effect of silica desiccation under different storage conditions on filter-immobilized environmental DNA.

OBJECTIVE: Silica gel beads have promise as a non-toxic, cost-effective, portable method for storing environmental DNA (eDNA) immobilized on filter membranes. Consequently, many ecological surveys are turning to silica bead filter desiccation rather than ethanol preservation. However, no systematic evaluation of silica bead storage conditions or duration past 1 week has been published. The present study evaluates the quality of filter-immobilized eDNA desiccated with silica gel under different storage conditions for over a year using targeted quantitative real-time polymerase chain reaction (qPCR)-based assays. RESULTS: While the detection of relatively abundant eDNA target was stable over 15 months from either ethanol- or silica gel-preserved filters at - 20 and 4 °C, silica gel out-performed ethanol preservation at 23 °C by preventing a progressive decrease in eDNA sample quality. Silica gel filter desiccation preserved low abundance eDNA equally well up to 1 month regardless of storage temperature (18, 4, or - 20 °C). However only storage at - 20 °C prevented a noticeable decrease in detectability at 5 and 12 months. The results indicate that brief storage of eDNA filters with silica gel beads up to 1 month can be successfully accomplished at a range of temperatures. However, longer-term storage should be at - 20 °C to maximize sample integrity.

Projecting thyroid cancer risk to the general public from radiation exposure following hypothetical severe nuclear accidents in Canada.

INTRODUCTION: A robust emergency management framework can limit radiation exposures and effectively minimize the potentially devastating consequences of a nuclear emergency. We projected thyroid cancer risk resulting from two hypothetical severe nuclear accidents occurring at the Darlington nuclear power plant (NPP) located in Ontario, Canada. METHODS: Single- and multi-unit accidents were considered. A dose assessment was previously performed using the MELCOR Accident Consequences Code System. The generic criteria used to select the appropriate protective actions are described in the Ontario Provincial Nuclear Emergency Response Plan (PNERP). We hypothesized protection actions only within the 10 kilometre (km) radius of the NPP given the time sensitivity of iodine thyroid blocking. The excess risk of developing thyroid cancer was projected using the US National Cancer Institute's radiation risk assessment tool RadRAT. RESULTS: We projected zero dose, and subsequently zero risk of developing thyroid cancer for people living within 10 km of the NPP, due to effective implementation of selected protective actions. Based on centreline doses, at the 12 km radius, excess childhood thyroid cancer risks of approximately 600% and 130% compared to the baseline were projected for the single- and multi-unit scenarios, respectively. The risk of developing thyroid cancer was projected to be low for adults for both scenarios. DISCUSSION: The results of this modelling study provide insights into the effectiveness of protective actions in reducing radiation-related thyroid cancer risk when considering hypothetical severe nuclear accidents. Implementation of select protective actions protects the population living near the Darlington NPP. The projected increase of developing thyroid cancer for children living beyond 10 km could potentially be eliminated with additional mitigation measures specified in the PNERP.

Fluorescence characterization of organic matter and fouling: Case study in a full-scale reverse osmosis membrane treatment plant.

Membranes used for water treatment are subject to organic fouling, caused by organic matter in source water. Characterizing organic matter has the potential to improve fouling prediction since the development of an organic fouling layer on the membrane is dependent on the specific characteristics of the organic matter. A field study was performed at a full-scale reverse osmosis water treatment plant that treats secondary wastewater effluent for industrial reuse at a power plant. Samples were collected at various points within the treatment process and were analyzed for turbidity, total organic carbon (TOC), conductivity, and fluorescence Excitation Emission Matrices (EEM). Parallel factor analysis (PARAFAC) was used to generate representative fluorescence measurements of the organic matter. Results indicate that TOC and fluorescence measurements were effective in differentiating between two observed fouling periods at multiple locations within the treatment plant. However, none of the water quality measurements were effective in tracking treatability of organic matter throughout pretreatment. The results of this case study provide important information about the relationship between fluorescence NOM signals and membrane fouling that can be used in future online detection systems. PRACTITIONER POINTS: TOC and fluorescence measurements were effective in differentiating between the high fouling and low fouling periods. Water quality measurements were not effective in tracking changes in organic matter throughout pretreatment. Implementation of online fluorescence monitoring of fouling potential could be used for real-time process control.

Radon exhalation from sub-slab aggregate used in home construction in Canada.

Exposure to elevated levels of radon in homes has been shown to result in an increased risk of developing lung cancer. The two largest contributors to indoor radon are radon in soil gas, formed from the rocks and soil surrounding the home, and building materials such as aggregate. This study measured the surface radon exhalation rates for 35 aggregate samples collected from producers across Canada. The radon exhalation rates ranged from 2.3 to 479.9 Bq m(-2) d(-1), with a mean of 80.7±112 Bq m(-2) d(-1). Using a simple, conservative analysis, the aggregate contribution to radon concentrations in an unfinished basement was determined. The maximum estimated radon concentration was 32.5±2.7 Bq m(-3), or ~16 % of the Canadian Radon Guideline. It can be concluded that under normal conditions radon exhalation from aggregate contributes very little to the total radon concentration in indoor air.

Results of simultaneous radon and thoron measurements in 33 metropolitan areas of Canada.

Radon has been identified as the second leading cause of lung cancer after tobacco smoking. (222)Rn (radon gas) and (220)Rn (thoron gas) are the most common isotopes of radon. In order to assess thoron contribution to indoor radon and thoron exposure, a survey of residential radon and thoron concentrations was initiated in 2012 with ∼4000 homes in the 33 census metropolitan areas of Canada. The survey confirmed that indoor radon and thoron concentrations are not correlated and that thoron concentrations cannot be predicted from widely available radon information. The results showed that thoron contribution to the radiation dose varied from 0.5 to 6% geographically. The study indicated that, on average, thoron contributes ∼3% of the radiation dose due to indoor radon and thoron exposure in Canada. Even though the estimated average thoron concentration of 9 Bq m(-3) (population weighted) in Canada is low, the average radon concentration of 96 Bq m(-3) (population weighted) is more than double the worldwide average indoor radon concentration. It is clear that continued efforts are needed to further reduce the exposure and effectively reduce the number of lung cancers caused by radon.

The design of Radiation Accident Registry.

In order to provide effective monitoring and follow-up on the health effects of individuals accidentally exposed to ionising radiation, a Radiation Accident Registry (RAR) has been designed and constructed as an extension to the existing National Dose Registry (NDR). The RAR has basic functions of recording, monitoring and reporting. This type of registry is able to assist responders in preparing for and managing situations during radiological events and in providing effective follow-up on the long-term health effects of persons exposed to ionising radiation. It is especially important to register radiation-exposed people in vulnerable population groups, such as children and pregnant women, to ensure proper long-term health care and protection. Even though radiation accidents are rare, a registry prepared for such accidents could involve a large population and, in some cases, require lifetime monitoring for individuals. One of the most challenging tasks associated with RAR is the assessment of radiation dose resulting from accidents. In some cases, the assessment of radiation doses to individuals could be a process requiring the involvement of various methods. The development of fast and accurate dose assessment tools will remain a long-term challenge associated with the RAR. To meet this challenge, further research activities in radiation dosimetry for individual monitoring are needed.

Development of a medical resource database for radiological emergency preparedness.

In order for Canada to be better prepared to respond quickly to a radiological or nuclear emergency detailed knowledge regarding the locations and capacities of hospitals, relevant medical supplies and radiological or nuclear professionals is needed. These key points of information were identified at a CRTI workshop in 2009, and it was proposed that a medical resource database (MRD) was required. This database is in addition to the development of a radiation accident registry which was also proposed at the CRTI Workshop in 2009. The MRD has been designed, built and populated where possible; it is now ready for field testing and deployment. The creation of the database is one more step towards a better and more effective response in a radiological or nuclear emergency. In order to maintain this database and keep it up to date, contributions from all levels of radiation protection professionals will be needed. In this paper, the database structure and the data collected will be presented and discussed.

Correlation of soil radon and permeability with indoor radon potential in Ottawa.

Soil gas radon and soil gas permeability measurements were conducted at 32 sites across the five most populated communities in the city of Ottawa where indoor radon measurements were available for 167 houses. A soil radon index (SRI) determined from the soil radon concentration and the soil gas permeability was used to characterise radon availability from soil to air. This study demonstrated that the average SRI in a community area correlates with the indoor radon potential (the percentage of homes above 200 Bq m(-3)) in that community. Soil gas radon concentrations together with soil gas permeability measurements can be a useful tool for the prediction of the indoor radon potential in the development of a Canadian radon risk map.

Long-term monitoring of soil gas radon and permeability at two reference sites.

The long-term monitoring of soil radon variations was conducted at two reference sites in Ottawa. The purpose of this study was to determine whether a single soil radon survey could provide a representative soil radon characteristic of the site. Results showed that during the normal field survey period from June to September in Canada, a single field survey with multiple measurements of soil gas radon concentrations at a depth of 80 cm can characterise the soil radon level of a site within a deviation of +/-30%. Direct in situ soil permeability measurements exhibited, however, large variations even within an area of only 10 x 10 m(2). Considering such large variations and the weight of the equipment, soil permeability can be determined by direct measurements whenever possible or by other qualitative evaluation methods for sites that are hard to access with heavy equipment.