TY - JOUR A1 - Vahlsing, Thorsten A1 - Delbeck, S. A1 - Leonhardt, S. A1 - Heise, H.M. T1 - Noninvasive monitoring of blood glucose using color-coded photoplethysmographic images of the illuminated fingertip within the visible and near-infrared range: Opportunities and questions N2 - Noninvasive blood glucose assays have been promised for many years and various molecular spectroscopy-based methods of skin are candidates for achieving this goal. Due to the small spectral signatures of the glucose used for direct physical detection, moreover hidden among a largely variable background, broad spectral intervals are usually required to provide the mandatory analytical selectivity, but no such device has so far reached the accuracy that is required for self-monitoring of blood glucose (SMBG). A recently presented device as described in this journal, based on photoplethysmographic fingertip images for measuring glucose in a nonspecific indirect manner, is especially evaluated for providing reliable blood glucose concentration predictions. KW - Color sensing KW - Noninvasive glucose sensing KW - Plethysmographic skin imaging KW - Skin tissue spectroscopy KW - Visible/near-infrared spectroscopy PY - 2018 U6 - https://doi.org/10.1177/1932296818798347 SN - 1932-2968 VL - 12 IS - 6 SP - 1169 EP - 1177 PB - Sage Publishing AN - OPUS4-46715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Delbeck, S. A1 - Vahlsing, Thorsten A1 - Leonhardt, S. A1 - Steiner, G. A1 - Heise, H.M. T1 - Non-invasive monitoring of blood glucose using optical methods for skin spectroscopy - opportunities and recent advances N2 - Diabetes mellitus is a widespread disease with greatly rising patient numbers expected in the future, not only for industrialized countries but also for regions in the developing world. There is a need for efficient therapy, which can be via self-monitoring of blood glucose levels to provide tight glycemic control for reducing the risks of severe health complications. Advancements in diabetes technology can nowadays offer different sensor approaches, even for continuous blood glucose monitoring. Non-invasive blood glucose assays have been promised for many years and various vibrational spectroscopy-based methods of the skin are candidates for achieving this goal. Due to the small spectral signatures of the glucose hidden among a largely variable background, the largest signal-to-noise ratios and multivariate calibration are essential to provide the method applicability for self-monitoring of blood glucose. Besides multiparameter approaches, recently presented devices based on photoplethysmography with wavelengths in the visible and near-infrared range are evaluated for their potential of providing reliable blood glucose concentration predictions. KW - Non-invasive glucose sensing KW - Vibrational spectroscopy KW - Photoplethysmography KW - Multivariate calibration KW - Validation studies PY - 2019 U6 - https://doi.org/10.1007/s00216-018-1395-x SN - 1618-2650 SN - 1618-2642 VL - 411 IS - 1 SP - 63 EP - 77 PB - Springer-Verlag GmbH Germany, part of Springer Nature AN - OPUS4-46714 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Vahlsing, Thorsten A1 - Raum, Hanne A1 - Casperson, Ralf A1 - Pohl, Rainer A1 - Heckel, Thomas A1 - Beilken, D. A1 - Dilz, K. A1 - Rühe, S. T1 - FE-simulation of eddy current signals produced from basic model cracks for running surface rail defects N2 - Non-destructive testing for surface crack detection and head check depth quantification at the gauge corner of railway tracks can be achieved using eddy current methods. With the extension of the tested zone to the running surface, rail defect signal types other than head checks can be measured. Due to their mostly irregular shape, a quantitation based on a calibration against regular test cracks of varying depth may not be linear. Estimates of the expected influence of more complex crack patterns may be obtained by a finite element simulation of sufficiently simple limiting cases, like two displaced or intersecting cracks or a simply branched or flexed crack. As a first step, a 3D finite element model of the HC10 eddy current probe distributed by Prüftechnik Linke und Rühe (PLR), Germany was built and verified against measured results from an (easily fabricated) reference block with isolated long cracks. T2 - 15th Railway Engineering Conference CY - Edinburgh, UK DA - 03.07.2019 KW - Finite element analysis KW - Eddy current testing KW - Rail inspection PY - 2019 SP - 1 EP - 11 AN - OPUS4-48529 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Vahlsing, Thorsten A1 - Raum, Hanne A1 - Casperson, Ralf A1 - Pohl, Rainer A1 - Heckel, Thomas A1 - Beilken, D. A1 - Dilz, K. A1 - Rühe, S. T1 - Fe-simulation of eddy current signals produced from basic model cracks for running surface rail defects N2 - Non-destructive testing for surface crack detection and head check depth quantification at the gauge cor-ner of railway tracks can be achieved using eddy current methods. With the extension of the tested zone to the running surface, rail defect signal types other than head checks can be measured. Due to their most-ly irregular shape, a quantitation based on a calibration against regular test cracks of varying depth may not be linear. Estimates of the expected influence of more complex crack patterns may be obtained by a finite element simulation of sufficiently simple limiting cases, like two displaced or intersecting cracks or a simply branched or flexed crack. As a first step, a 3D finite element model of the HC10 eddy current probe distributed by Prüftechnik Linke und Rühe (PLR), Germany was built and verified against meas-ured results from an (easily fabricated) reference block with isolated long cracks. T2 - Railway Engineering 2019 CY - Edinburgh, UK DA - 03.07.2019 KW - Finite element analysis KW - Eddy current testing KW - Rail inspection PY - 2019 AN - OPUS4-49686 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -