TY - JOUR A1 - Holländer, Olivia A1 - Schwender, Kristina A1 - Böhme, Petra A1 - Fleckhaus, Jan A1 - Haas, Cordula A1 - Han, Yang A1 - Heidorn, Frank A1 - Klein-Unseld, Rachel A1 - Lichtenwald, Julia A1 - Naue, Jana A1 - Neubauer, Jacqueline A1 - Poetsch, Micaela A1 - Schneider, Peter M. A1 - Wagner, Wolfgang A1 - Vennemann, Marielle T1 - Forensische DNA-Methylierungsanalyse T1 - Forensic DNA methylation analysis : First technical collaborative exercise by the working group on molecular age estimation of the German Society of Legal Medicine BT - Erster, technischer Ringversuch der Arbeitsgruppe „Molekulare Altersschätzung“ der Deutschen Gesellschaft für Rechtsmedizin JF - Rechtsmedizin N2 - Die quantitative Analyse der relativen DNA-Methylierung gilt als eine der vielversprechendsten Methoden der molekularen Altersschätzung. Viele Studien der letzten Jahre identifizierten geeignete Positionen im Genom, deren DNA-Methylierung sich altersabhängig verändert. Für den Einsatz dieser Methode in der Routine- bzw. Fallarbeit ist es von großer Bedeutung, angewandte Analysetechniken zu validieren. Als ein Teilaspekt dieser Validierung sollte die Vergleichbarkeit der Analyseergebnisse zur DNA-Methylierung mithilfe der Mini- und Pyrosequenzierung zwischen verschiedenen Laboren evaluiert werden. Die Arbeitsgruppe „Molekulare Altersschätzung“ der Deutschen Gesellschaft für Rechtsmedizin (DGRM) führte hierzu den ersten, technischen Ringversuch durch, der 4 Positionen in den Genen PDE4C, EDARADD, SST und KLF14 umfasste. Diese Marker waren in vorangegangenen Studien als altersabhängige Biomarker charakterisiert worden. Am Ringversuch nahmen 12 Labore teil, wobei jedes die Wahl zwischen der Minisequenzierung und/oder der Pyrosequenzierung für die quantitative Methylierungsanalyse hatte. Jedem teilnehmenden Labor wurden Blut- und Speichelproben von 3 Personen unterschiedlichen Alters übersandt. Die Wahl der Reagenzien für die Probenbearbeitung wurde den Teilnehmern freigestellt. Die Ergebnisse der Minisequenzierung zeigten systematische Abweichungen zwischen den Laboren, die am ehesten auf die Verwendung unterschiedlicher Reagenzien und Analyseplattformen zurückzuführen sein können. Die Resultate der Pyrosequenzierung hingegen wiesen nicht auf systematische Abweichungen zwischen den Laboren hin, hier zeigte sich jedoch die Tendenz einer markerabhängigen Abweichung. Darüber hinaus konnten Unterschiede hinsichtlich technischer Probleme zwischen Laboren mit mehr Erfahrung in der jeweiligen Sequenzierungsmethode und Laboren mit weniger Erfahrung festgestellt werden. Sowohl die Beobachtung von systematischen als auch die von markerabhängigen Abweichungen lässt den Schluss zu, dass eine Übertragung von Analysemethoden zwischen Laboren grundsätzlich möglich ist, eine Anpassung des jeweiligen Modells zur Altersschätzung jedoch notwendig sein kann. N2 - Quantitative analysis of relative DNA methylation is currently one of the most promising methods of molecular age estimation. In recent years numerous studies identified potential DNA methylation markers showing age-dependent changes in their relative methylation state. For routine application of this method validation is an important prerequisite. One aspect of validation is the degree of comparability of analytical data between laboratories. The working group on molecular age estimation of the German Society for Legal Medicine (DGRM) conducted a first technical proficiency test comprising four age estimation markers within the genes PDE4C, EDARADD, SST and KLF14. These positions were previously characterized as age-dependent biomarkers. A total of 12 laboratories participated using pyrosequencing and/or minisequencing techniques for quantitative analysis of DNA methylation. Each laboratory received blood and buccal swab samples from three individuals of different ages. Laboratories were free in their choice of reagents and material for sequencing. Minisequencing results showed systematic deviations between laboratories, which are believed to originate from differing reagents and sequencing platforms. The results of pyrosequencing did not show clear signs of systematic deviation but did show differences in the comparability between markers. Different levels of technical problems were reported, which correlated with the amount of experience with the sequencing technology. Both systematic and specific differences between analytical data produced in different laboratory settings lead to the conclusion that while it is generally possible to transfer an age estimation method to another laboratory, a mathematical model for age estimation might need to be adjusted accordingly. KW - DNA-Methylierung KW - Pyrosequenzierung KW - Minisequenzierung KW - Ergebnisreproduzierbarkeit KW - Laborleistungstests KW - DNA methylation KW - minisequencing KW - pyrosequencing KW - reproducibility of results KW - laboratory proficiency testing Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-307131 SN - 0937-9819 SN - 1434-5196 VL - 31 IS - 3 ER - TY - JOUR A1 - Nguyen, Duy Ba A1 - Kersten, Clauss A1 - Senmao, Cao A1 - Vahid, Naeimi A1 - Kuenzer, Claudia A1 - Wagner, Wolfgang T1 - Mapping Rice Seasonality in the Mekong Delta with Multi-Year Envisat ASAR WSM Data JF - Remote Sensing N2 - Rice is the most important food crop in Asia, and the timely mapping and monitoring of paddy rice fields subsequently emerged as an important task in the context of food security and modelling of greenhouse gas emissions. Rice growth has a distinct influence on Synthetic Aperture Radar (SAR) backscatter images, and time-series analysis of C-band images has been successfully employed to map rice fields. The poor data availability on regional scales is a major drawback of this method. We devised an approach to classify paddy rice with the use of all available Envisat ASAR WSM (Advanced Synthetic Aperture Radar Wide Swath Mode) data for our study area, the Mekong Delta in Vietnam. We used regression-based incidence angle normalization and temporal averaging to combine acquisitions from multiple tracks and years. A crop phenology-based classifier has been applied to this time series to detect single-, double- and triple-cropped rice areas (one to three harvests per year), as well as dates and lengths of growing seasons. Our classification has an overall accuracy of 85.3% and a kappa coefficient of 0.74 compared to a reference dataset and correlates highly with official rice area statistics at the provincial level (R-2 of 0.98). SAR-based time-series analysis allows accurate mapping and monitoring of rice areas even under adverse atmospheric conditions. KW - band SAR data KW - SAR KW - rice KW - WSM KW - ASAR KW - Envisat KW - MODIS image KW - Southeast China KW - polarimetric SAR KW - cropping systems KW - time-series KW - paddy rice KW - radar KW - paddy KW - rice mapping KW - Vietnam KW - Mekong-Delta KW - synthetic aperture radar KW - multitemporal ALOS/PALSAR imagery KW - soil moisture retrieval Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137554 VL - 7 IS - 12 ER - TY - JOUR A1 - Naeimi, Vahid A1 - Leinenkugel, Patrick A1 - Sabel, Daniel A1 - Wagner, Wolfgang A1 - Apel, Heiko A1 - Kuenzer, Claudia T1 - Evaluation of Soil Moisture Retrieval from the ERS and Metop Scatterometers in the Lower Mekong Basin JF - Remote Sensing N2 - The natural environment and livelihoods in the Lower Mekong Basin (LMB) are significantly affected by the annual hydrological cycle. Monitoring of soil moisture as a key variable in the hydrological cycle is of great interest in a number of Hydrological and agricultural applications. In this study we evaluated the quality and spatiotemporal variability of the soil moisture product retrieved from C-band scatterometers data across the LMB sub-catchments. The soil moisture retrieval algorithm showed reasonable performance in most areas of the LMB with the exception of a few sub-catchments in the eastern parts of Laos, where the land cover is characterized by dense vegetation. The best performance of the retrieval algorithm was obtained in agricultural regions. Comparison of the available in situ evaporation data in the LMB and the Basin Water Index (BWI), an indicator of the basin soil moisture condition, showed significant negative correlations up to R = −0.85. The inter-annual variation of the calculated BWI was also found corresponding to the reported extreme hydro-meteorological events in the Mekong region. The retrieved soil moisture data show high correlation (up to R = 0.92) with monthly anomalies of precipitation in non-irrigated regions. In general, the seasonal variability of soil moisture in the LMB was well captured by the retrieval method. The results of analysis also showed significant correlation between El Niño events and the monthly BWI anomaly measurements particularly for the month May with the maximum correlation of R = 0.88. KW - soil moisture KW - scatterometer KW - ASCAT KW - Mekong Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130480 VL - 5 IS - 4 ER -