105 research outputs found
patRoon 2.0: Improved non-target analysis workflows including automated transformation product screening
No full textpeer reviewedNon-target analysis (NTA) via chromatography coupled to high resolution mass spectrometry (HRMS) is used to monitor and identify organic chemicals in the environment. Biotic and abiotic processes can transform original chemicals (parents) into transformation products (TPs). These TPs can be of equal or more concern than their parent compounds and are therefore critical to monitor and identify in the environment (Escher & Fenner, 2011; Farré et al., 2008), often with NTA. Given the amount of data generated by NTA, advanced automated data processing workflows are essential. The open-source, R-based (R Core Team, 2021) platform patRoon (Helmus, ter Laak, et al., 2021) offers automated, straightforward, flexible and comprehensive NTA workflows.
This article describes improvements introduced in patRoon 2.0, including extensive TP screening and simultaneous processing of positive and negative HRMS data. The updated documentation and code are available via https://rickhelmus.github.io/patRoon and archived in Helmus, Velde, et al. (2021)
Supercritical fluid chromatography – Mass spectrometry in metabolomics:Past, present, and future perspectives
No full textMetabolomics, which consists of the comprehensive analysis of metabolites within a biological system, has been playing a growing role in the implementation of personalized medicine in modern healthcare. A wide range of analytical approaches are used in metabolomics, notably mass spectrometry (MS) combined to liquid chromatography (LC), gas chromatography (GC), or capillary electrophoresis (CE). However, none of these methods enable a comprehensive analysis of the metabolome, due to its extreme complexity and the large differences in physico-chemical properties between metabolite classes. In this context, supercritical fluid chromatography (SFC) represents a promising alternative approach to improve the metabolome coverage, while further increasing the analysis throughput. SFC, which uses supercritical CO2 as mobile phase, leads to numerous advantages such as improved kinetic performance and lower environmental impact. This chromatographic technique has gained a significant interest since the introduction of advanced instrumentation, together with the introduction of dedicated interfaces for hyphenating SFC to MS. Moreover, new developments in SFC column chemistry (including sub-2 µm particles), as well as the use of large amounts of organic modifiers and additives in the CO2-based mobile phase, significantly extended the application range of SFC, enabling the simultaneous analysis of a large diversity of metabolites. Over the last years, several applications have been reported in metabolomics using SFC-MS – from lipophilic compounds, such as steroids and other lipids, to highly polar compounds, such as carbohydrates, amino acids, or nucleosides. With all these advantages, SFC-MS is promised to a bright future in the field of metabolomics.</p
Clean subglacial access: prospects for future deep hot-water drilling
No full textAccessing and sampling subglacial environments deep beneath the Antarctic Ice Sheet presents several challenges to existing drilling technologies. With over half of the ice sheet believed to be resting on a wet bed, drilling down to this environment must conform to international agreements on environmental stewardship and protection, making clean hot-water drilling the most viable option. Such a drill, and its water recovery system, must be capable of accessing significantly greater ice depths than previous hot-water drills, and remain fully operational after connecting with the basal hydrological system. The Subglacial Lake Ellsworth (SLE) project developed a comprehensive plan for deep (greater than 3000?m) subglacial lake research, involving the design and development of a clean deep-ice hot-water drill. However, during fieldwork in December 2012 drilling was halted after a succession of equipment issues culminated in a failure to link with a subsurface cavity and abandonment of the access holes. The lessons learned from this experience are presented here. Combining knowledge gained from these lessons with experience from other hot-water drilling programmes, and recent field testing, we describe the most viable technical options and operational procedures for future clean entry into SLE and other deep subglacial access targets.<br/
Energy balance related behaviour: personal, home- and friend-related factors among schoolchildren in Europe studied in the ENERGY-project
No full textTo design interventions that target energy balance-related behaviours, knowledge of primary schoolchildren's perceptions regarding soft drink intake, fruit juice intake, breakfast consumption, TV viewing and physical activity (PA) is essential. The current study describes personal beliefs and attitudes, home- and friend-related variables regarding these behaviours across Europe.; Cross-sectional study in which personal, family and friend -related variables were assessed by validated questionnaires, and dichotomized as favourable versus unfavourable answers. Logistic regression analyses were conducted to estimate proportions of children giving unfavourable answers and test between-country differences.; A survey in eight European countries.; A total of 7903 10-12 year old primary schoolchildren.; A majority of the children reported unfavourable attitudes, preferences and subjective norms regarding soft drink, fruit juice intake and TV viewing accompanied with high availability and accessibility at home. Few children reported unfavourable attitudes and preferences regarding breakfast consumption and PA. Many children reported unfavourable health beliefs regarding breakfast consumption and TV viewing. Substantial differences between countries were observed, especially for variables regarding soft drink intake, breakfast consumption and TV viewing.; The surveyed children demonstrated favourable attitudes to some healthy behaviours (PA, breakfast intake) as well as to some unhealthy behaviours (soft drink consumption, TV viewing). Additionally, many children across Europe have personal beliefs and are exposed to social environments that are not supportive to engagement in healthy behaviours. Moreover, the large differences in personal, family and friend-related variables across Europe argue for implementing different strategies in the different European countries
Contribution à l'étude des protéines halogénées; II. La bromo-peptone /
No full textOverdruk uit: Recueil des travaux chimiques des Pays-Bas, 5(1924)
Regions in crisis:The volatility of regional identity in Face of nationalization projects. The Case of Schleswig
No full textRegions in crisis:The volatility of regional identity in Face of nationalization projects. The Case of Schleswig
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(Un)familiarity in mobility practices:Contemporary and historic experiences from Schleswig and former Yugoslavia
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