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Introduction: Van Krevelen (VK) diagrams provide a promising but uncommon solution to a number of challenges associated with the visualization of metabolomics data. VK diagrams are created by plotting H:C ratios against O:C ratios of the compounds in a chemical mixture.
Objectives: The aim of this manuscript is to present an open-source software tool and reference map that we have developed to make VK diagrams for visualization of metabolomics data.
Methods: Software was created with a prompt-driven command line user interface and was written using Python 2.7. We empirically derived an accompanying map by plotting where compounds from seven biomolecule types fall within the VK plot space.
Results: We've created an easy to use, open source software tool named OpenVanKrevelen for making a range of VK diagrams that is available on GitHub: https://github.com/HegemanLab/VanKrevelenLocal . The empirical mapping approach has produced several improvements from previously published maps.
Conclusions: OpenVanKrevelen provides the metabolomics community with access to a new tool for visualization of complex metabolomics datasets.
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http://dx.doi.org/10.1007/s11306-018-1343-y | DOI Listing |
Nat Comput
April 2016
Leiden Institute of Advanced Computer Science, Leiden University, Niels Bohrweg 1, 2333 CA Leiden, The Netherlands.
The vehicle routing problem is a classical combinatorial optimization problem. This work is about a variant of the vehicle routing problem with dynamically changing orders and time windows. In real-world applications often the demands change during operation time.
View Article and Find Full Text PDFAliment Pharmacol Ther
August 1999
Department of Medical Physiology and Sports Medicine, Utrecht University, Utrecht, The Netherlands.
Background: Strenuous exercise exacerbates gastro-oesophageal reflux and symptoms and this may be diminished by antisecretory medication with omeprazole.
Methods: Fourteen well-trained athletes (13 men, one woman), who indicated suffering from either heartburn, regurgitation or chest pain during competition running, performed two experimental trials at 2-week intervals using a randomized, double-blind, placebo-controlled crossover design. During the 6 days preceding the trial and on the trial day itself either 20 mg of omeprazole or a placebo was administered.
J Subst Abuse
March 1999
Addictive Disorders Section, Department of Veterans Affairs Medical Center, Minneapolis, MN 55417, USA.
Previous research (Isenhart, 1997) has shown a relationship between pre-treatment stages of change and outcome. The objective of this project was to evaluate whether certain processes of change measures predicted stages of change measures. A stepwise multiple regression model used Contemplation, Determination, and Action scores as dependent variables and process of change scores and measures of alcohol dependence severity and pre-treatment alcohol consumption as independent variables.
View Article and Find Full Text PDFRev Sci Instrum
July 1979
Department of Animal Physiology, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands.
A method is described for building a low-voltage-drift differential dc amplifier featuring automatic zero adjustment, a high input impedance, and a bandwidth of 10 kHz. This is achieved by an asymmetric two-step process between the input signal and ground. Bandwidth can be extended by the use of a second amplifier during the ground-sampling time.
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