6 research outputs found
Segmentation and supervised classification of image objects in Epo doping-control
Abstract A software system Gel Analysis System for Epo (GASepo) has been developed within an international WADA project. As recent WADA criteria of rEpo positivity are based on identification of each relevant object (band) in Epo images, development of suitable methods of image segmentation and object classification were needed for the GASepo system. In the paper we address two particular problems: segmentation of disrupted bands and classification of the segmented objects into three or two classes. A novel band projection operator is based on convenient object merging measures and their discrimination analysis using specifically generated training set of segmented objects. A weighted ranks classification method is proposed, which is new in the field of image classification. It is based on ranks of the values of a specific criterial function. The weighted ranks classifiers proposed in our paper have been evaluated on real samples of segmented objects of Epo images and compared t
Isoprene and acetone concentration profiles during exercise on an ergometer
A real-time recording setup combining exhaled breath VOC measurements by
proton transfer reaction mass spectrometry (PTR-MS) with hemodynamic and
respiratory data is presented. Continuous automatic sampling of exhaled breath
is implemented on the basis of measured respiratory flow: a flow-controlled
shutter mechanism guarantees that only end-tidal exhalation segments are drawn
into the mass spectrometer for analysis.
Exhaled breath concentration profiles of two prototypic compounds, isoprene
and acetone, during several exercise regimes were acquired, reaffirming and
complementing earlier experimental findings regarding the dynamic response of
these compounds reported by Senthilmohan et al. [1] and Karl et al. [2]. While
isoprene tends to react very sensitively to changes in pulmonary ventilation
and perfusion due to its lipophilic behavior and low Henry constant,
hydrophilic acetone shows a rather stable behavior. Characteristic (median)
values for breath isoprene concentration and molar flow, i.e., the amount of
isoprene exhaled per minute are 100 ppb and 29 nmol/min, respectively, with
some intra-individual day-to-day variation. At the onset of exercise breath
isoprene concentration increases drastically, usually by a factor of ~3-4
within about one minute. Due to a simultaneous increase in ventilation, the
associated rise in molar flow is even more pronounced, leading to a ratio
between peak molar flow and molar flow at rest of ~11.
Our setup holds great potential in capturing continuous dynamics of
non-polar, low-soluble VOCs over a wide measurement range with simultaneous
appraisal of decisive physiological factors affecting exhalation kinetics.Comment: 35 page