PURPOSE: To analyse how decisions to dichotomise the frequency and impediment of phantom pain into absent and present influence the outcome of studies by performing a sensitivity analysis on an existing database.METHOD: Five hundred and thirty-six subjects were recruited from the database of an orthopaedic workshop and filled out a questionnaire in which the following items were assessed: demographics, side, date, level and reason of amputation, presence and frequency of phantom sensations, phantom pain and stump pain, and impediment due to phantom pain.RESULTS: The prevalence of phantom pain ranged from 7-72% when different cut off points for the frequency of phantom pain were applied. The significance of the various risk factors for the prevalence of phantom pain changed when different cut off points were applied. Only stump pain and phantom sensations were significant risk factors for all cut off points. Risk factors for the impediment of phantom pain changed when different cut off points were applied and these risk factors were different from those for the prevalence of phantom pain.CONCLUSION: The choice of cut off points influences the outcome of phantom pain studies considerably. This study provides some insight into the differences in prevalence and risk factors found in literature.
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Evaluations of forensic observations considering activity level propositions are becoming more common place in forensic institutions. A measure that can be taken to interrogate the evaluation for robustness is called sensitivity analysis. A sensitivity analysis explores the sensitivity of the evaluation to the data used when assigning probabilities, or to the level of uncertainty surrounding a probability assignment, or to the choice of various assumptions within the model. There have been a number of publications that describe sensitivity analysis in technical terms, and demonstrate their use, but limited literature on how that theory can be applied in practice. In this work we provide some simplified examples of how sensitivity analyses can be carried out, when they are likely to show that the evaluation is sensitive to underlying data, knowledge or assumptions, how to interpret the results of sensitivity analysis, and how the outcome can be reported. We also provide access to an application to conduct sensitivity analysis.
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Standard SARS-CoV-2 testing protocols using nasopharyngeal/throat (NP/T) swabs are invasive and require trained medical staff for reliable sampling. In addition, it has been shown that PCR is more sensitive as compared to antigen-based tests. Here we describe the analytical and clinical evaluation of our in-house RNA extraction-free saliva-based molecular assay for the detection of SARS-CoV-2. Analytical sensitivity of the test was equal to the sensitivity obtained in other Dutch diagnostic laboratories that process NP/T swabs. In this study, 955 individuals participated and provided NP/T swabs for routine molecular analysis (with RNA extraction) and saliva for comparison. Our RT-qPCR resulted in a sensitivity of 82,86% and a specificity of 98,94% compared to the gold standard. A false-negative ratio of 1,9% was found. The SARS-CoV-2 detection workflow described here enables easy, economical, and reliable saliva processing, useful for repeated testing of individuals.
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Environmental nano- and micro-plastics (NMPs) are highly diverse [2]. Accounting for this diversity is one of the main challenges to develop a comprehensive understanding of NMPs detection, quantification, fate, and risks [3]. Two major issues currently limit progresses within this field: (a) validation and broadening the current analytical tools (b) uncertainty with respect to NMPs occurrence and behaviour at small scales (< 20 micron). Tracking NMPs in environmental systems is currently limited to micron size plastics due to the size detection limit of the available analytical techniques. There are currently many uncertainties regarding detecting nanoplastics in real environmental systems, e.g. the inexistence of commercially available NMPs and incompatibility between them and those generated from plastic fragments degradation in the environment. Trying to tackle these problems some research groups synthesized NMPs dopped with metals inside [16]. However, even though elemental analysis techniques (ICP-MS) are rather sensitive, the low volume of these metals encapsulated in the nanoparticles make their detection rather challenging. At the same time, due to Sars-Cov-19 pandemic, nucleic acid identification technologies (LAMP, PCR) experienced a fast evolution and are able to provide detection at very low levels with very compact and reliable equipment. Nuclepar proposes the use of Electrohydrodynamic Atomization (EHDA) to generate NMPs coated with nucleic acids of different polymer types, sizes, and shapes, which can be used as support for detection of such particles using PCR-LAMP technology. If proven possible, Nuclepar might become a first step towards an easy NMPs detection tool. This knowledge will certainly impact current risk assessment tools, efficient interventions to limit emissions and adequate regulations related to NMPs.
