Evaluation of Handheld Assays for the Detection of Ricin and Staphylococcal Enterotoxin B in Disinfected Waters

Development of a rapid field test is needed capable of determining if field supplies of water are safe to drink by the warfighter during a military operation. The present study sought to assess the effectiveness of handheld assays (HHAs) in detecting ricin and Staphylococcal Enterotoxin B (SEB) in water. Performance of HHAs was evaluated in formulated tap water with and without chlorine, reverse osmosis water (RO) with chlorine, and RO with bromine. Each matrix was prepared, spiked with ricin or SEB at multiple concentrations, and then loaded onto HHAs. HHAs were allowed to develop and then read visually. Limits of detection (LOD) were determined for all HHAs in each water type. Both ricin and SEB were detected by HHAs in formulated tap water at or below the suggested health effect levels of 455 ng/mL and 4.55 ng/mL, respectively. However, in brominated or chlorinated waters, LODs for SEB increased to approximately 2,500 ng/mL. LODs for ricin increased in chlorinated water, but still remained below the suggested health effect level. In brominated water, the LOD for ricin increased to approximately 2,500 ng/mL. In conclusion, the HHAs tested were less effective at detecting ricin and SEB in disinfected water, as currently configured

Phylogenetic ctDNA analysis depicts early-stage lung cancer evolution.

The early detection of relapse following primary surgery for non-small-cell lung cancer and the characterization of emerging subclones, which seed metastatic sites, might offer new therapeutic approaches for limiting tumour recurrence. The ability to track the evolutionary dynamics of early-stage lung cancer non-invasively in circulating tumour DNA (ctDNA) has not yet been demonstrated. Here we use a tumour-specific phylogenetic approach to profile the ctDNA of the first 100 TRACERx (Tracking Non-Small-Cell Lung Cancer Evolution Through Therapy (Rx)) study participants, including one patient who was also recruited to the PEACE (Posthumous Evaluation of Advanced Cancer Environment) post-mortem study. We identify independent predictors of ctDNA release and analyse the tumour-volume detection limit. Through blinded profiling of postoperative plasma, we observe evidence of adjuvant chemotherapy resistance and identify patients who are very likely to experience recurrence of their lung cancer. Finally, we show that phylogenetic ctDNA profiling tracks the subclonal nature of lung cancer relapse and metastasis, providing a new approach for ctDNA-driven therapeutic studies

Students generating questions for their own written examinations

Abstract Assessment partnerships between staff and students are considered a vital component of the student-centred educational process. To enhance the development of this partnership in a problem-based learning curriculum, all first-year students were involved in generating a bank of formative assessment questions with answers, some of which were included in their final written examination. Important principles to guide development of a sound methodology for such an assessment partnership have been described. These include organisational issues as well as matters pertaining to participation, education and motivation of students and teaching staff

Effects of a metacognitive intervention on students' approaches to learning and self-efficacy in a first year medical course

Aim To determine the influence of metacognitive activities within the PBL tutorial environment on the development of deep learning approach, reduction in surface approach, and enhancement of individual learning self-efficacy. Method: Participants were first-year medical students (N = 213). A pre-test, post-test design was implemented with intervention and control cohorts, with intervention students experiencing a program of metacognitive activities within their PBL tutorials of at least 20 weeks duration. All students completed the Medical Course Learning Questionnaire at the commencement, and again at the completion of, the study. The metacognitive intervention itself consisted of reflection on the learning in PBL coupled with peer- and self-assessment. Results: Self-efficacy was significantly reduced for both control and intervention cohorts at the conclusion of the study. A significant reduction in the adoption of deep and strategic learning approach, matched by a corresponding increase in the use of surface learning, was demonstrated for both cohorts. There was a statistically significant association between high self-efficacy and deep learning approach, with older students over-represented in the group of efficacious deep learners. Conclusion: Over the course of first-year medical studies, students lose self-efficacy and move away from deep-strategic learning approaches towards more surface approaches. The program of metacognitive activities failed to reverse this trend. The substantial swing towards surface learning raises questions about the perceived capacity of PBL curricula to promote deep approaches to learning in dense curricula, and reinforces the importance of personal and contextual factors, such as study habits, workload and assessment, in determining individual approaches and idiosyncratic responses to learning situations