46 research outputs found
Spejlinger ved himlens fod
No full textSmukt anlagt fotobog, der fortæller historien om vandspejlet i en skovsø i Danmark hen over årstidern
Real‐time versus thermal desorption selected ion flow tube mass spectrometry for quantification of breath volatiles
No full textRationale Selected ion flow tube mass spectrometry (SIFT-MS) is versatile, rapidly provides result output and determines a wide range of volatiles, making it suitable for biomedical applications. When direct sampling into the SIFT-MS instrument is impractical, combining thermal desorption (TD) and SIFT-MS might offer a solution as it allows sample storage on sorbent tubes for later analysis. This work compares off-line TD SIFT-MS and real-time SIFT-MS for the quantification of selected breath volatiles. Methods Ten healthy non-smoking individuals provided 60 breath samples per method. For off-line analysis, breath was collected onto sorbent tubes via a breath sampler provided with filtered inspiratory air. After TD, samples were re-collected in Tedlar bags which were then connected to the SIFT-MS instrument. For real-time analysis, breath was sampled directly into the instrument. In both cases the analytical method included a total of 155 product ions, and 14 selected volatiles were quantified. The agreement between the methods was assessed using Pearson correlation coefficients and Bland-Altman plots. Results Overall, correlations between real-time and off-line analysis were moderate to very strong (r = 0.43-0.92) depending on the volatile of interest, except for 2,3-butanedione and styrene. The difference between real-time and off-line measured breath concentrations (average bias) ranged between -14.57 and 20.48 ppbv. For acetone and isoprene, it was 251.53 and 31.9 ppbv, respectively. Conclusions Real-time SIFT-MS and off-line TD SIFT-MS for quantification of selected breath volatiles did not show optimal agreement. Analyzing a multitude of analytes in breath via direct exhalation into a SIFT-MS instrument for real-time analysis is challenging. On the other hand, off-line analysis using a breath collection device also has its issues such as possible sample losses due to selective absorption depending on the sorbent used or during desorption and transfer to the instrument. Despite these drawbacks, both methods were moderately well correlated.The authors thank all the volunteers for participating in this study. The authors also thank the coordinator and other parties of the Peppermint Consortium for the opportunity to participate in the benchmarking study. M.V.E. was supported by the University Research Fund of the University of Antwerp. G.S. is supported by the Limburg Clinical Research Center (LCRC) UHasselt-ZOL-Jessa, supported by the foundation Limburg Sterk Merk, province of Limburg, Flemish government, Hasselt University, Jessa Hospital and Ziekenhuis Oost-Limburg.Koppen, G (corresponding author), VITO Hlth, Flemish Inst Technol Res, B-2400 Mol, Belgium. [email protected]
Real-time selected ion flow tube mass spectrometry to assess short- and long-term variability in oral and nasal breath
No full textBreath-based non-invasive diagnostics have the potential to provide valuable information about a person's health status. However, they are not yet widely used in clinical practice due to multiple factors causing variability and the lack of standardized procedures. This study focuses on the comparison of oral and nasal breathing, and on the variability of volatile metabolites over the short and long term. Selected ion flow tube mass spectrometry (SIFT-MS) was used for online analysis of selected volatile metabolites in oral and nasal breath of 10 healthy individuals five times in one day (short-term) and six times spread over three weeks (long-term), resulting in nearly 100 breath samplings. Intra-class correlation coefficients (ICCs) were used to assess short- and long-term biological variability. Additionally, the composition of ambient air was analyzed at different samplings. The selected volatiles common in exhaled breath were propanol, 2,3-butanedione, acetaldehyde, acetone, ammonia, dimethyl sulfide, isoprene, pentane, and propanal. Additionally, environmental compounds benzene and styrene were analyzed as well. Volatile metabolite concentrations in ambient air were not correlated with those in exhaled breath and were significantly lower than in breath samples. All volatiles showed significant correlation between oral and nasal breath. Five were significantly higher in oral breath compared to nasal breath, while for acetone, propanal, dimethyl sulfide, and ammonia, concentrations were similar in both matrices. Variability depended on the volatile metabolite. Most physiologically relevant volatiles (acetone, isoprene, propanol, acetaldehyde) showed good to very good biological reproducibility (ICC > 0.61) mainly in oral breath and over a short-term period of one day. Both breathing routes showed relatively similar patterns; however, bigger differences were expected. Therefore, since sampling from the mouth is practically more easy, the latter might be preferred.The authors thank all the volunteers for participating in this study. Janssens H and Vanden Eede M were supported by the University Research Fund of the University of Antwerp. Slingers G was supported by the Limburg Clinical Research Center (LCRC) UHasselt-ZOL-Jessa, supported by the foundation Limburg Sterk Merk, province of Limburg, Flemish government, Hasselt University, Jessa Hospital, and Ziekenhuis Oost-Limburg.Koppen, G (corresponding author), Flemish Inst Technol Res, Unit Hlth, B-2400 Mol, Belgium.
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Hourly Traffic Density Based Decomposition in Non-Centralised Railway Traffic Management
No full textThe Dutch railway network is a dense network with 7000 kilometers of railway tracks spread over only 42 000 square kilometers [1, 2]. Additionally, the railways are responsible for 1.4 million passengers every working day [1]. These factors make both the infrastructure and timetable of the Dutch railway network extremely intricate. On top of that, the amount of train trips is expected to grow with 40 % by 2040 [3] and with that the complexity of managing the railway network will increase even more. In the case of conflict in the timetable, action must be taken to resolve this conflict in order for the train operations to continue. In current Dutch practice this task resides with the train dispatchers. However it can be difficult for the dispatcher to oversee the situation when multiple trains get involved and taken actions will have consequences on yet another selection of trains. This increasingly complex task has resulted in a grown interest in so-called Traffic Management Systems (TMS), which are an intelligent systems that use a conflict resolution algorithm to find a solution to a conflict. A TMS can be used to support the train dispatcher...Mechanical Engineering | Multi-Machine Engineerin
Weighting of individuating information elements and base rates in a nursing decision-making task involving non-diagnostic case information
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Neoliberalism, individual responsibilization and the death positivity movement
No full textIn this article I offer a critical analysis of the loosely defined death positivity movement. Death positivity presents itself as oppositional and liberating, gaining legitimacy by reference to the narratives of death taboo and death denial. I show how the movement encourages extending continuous, self-reflexive engagement in identity and lifestyle to dying and death, arguing that death positivity employs and advocates a particular enterprising culture and furthers a neoliberal discourse of individual responsibilization. To make my argument, I look more closely at the death-positive discourse as it is furthered by two North American initiatives in particular; Death Over Dinner as presented by its founder Michael Hebb in the 2018 book about the initiative, and selected videos published by Order of the Good Death, spearheaded by mortician, author and YouTube personality Caitlin Doughty
Learning throughout the Innovation Journey:A new dimension to Learning as a Search Process
Get PDFDenne artikel forsøger at udforske praksislæring hos professionelle fagfolk i et konkret innovativt uddannelsesprojekt. Her forstås praksislæring gennem læring defineret som en søgeproces. I denne artikel stilles spørgsmålstegn ved forforståelsen af innovation i den offentlige sektor, hvor kaotiske læringsprocesser kan begrænses til den idégenererende fase. Forfatteren hævder, at læringsprocesser gennem kaotiske søgeprocesser finder sted gennem hele innovationsprocessen og hævder, at læring gennem søgeprocesser har forskellige karakteristika og dimensioner, hvilket resulterer i læring gennem udforskning og læring gennem test i en kollektiv professionel ramme. Gennem udforskning af en konkret innovationsproces inden for uddannelse hævder forfatteren, at læring som søgeproces kan have implikationer for fremtidige offentlige innovationsprojekter.This article explores learning processes of professionals in a case of innovation in education. Learning of professionals is here defined as a collective search process – in contrast to a predominant understanding of innovation in the public sector where learning primarily leads to knowledge gain and can be limited to the idea-generating phase. Based on a case study of a concrete innovation process in an educational network the working hypothesis is that practice learning comes as iterative search processes through discovery and takes place throughout innovation. A key finding points to learning through search has different characteristics and dimensions, and hence has effect on organizational culture and identity. The author argues that there is an until now uncovered part of the learning process with implications for understanding learning in funded public sector projects, and hence the article contributes to a change in the way learning can be understood in educational innovation
