TY - JOUR A1 - Wilke, Franziska Daniela Helena A1 - Schettler, Georg A1 - Vieth-Hillebrand, Andrea A1 - Kühn, Michael A1 - Rothe, Heike T1 - Activity concentrations of U-238 and Ra-226 in two European black shales and their experimentally-derived leachates JF - Journal of Environmental Radioactivity N2 - We performed leaching tests at elevated temperatures and pressures with an Alum black shale from Bomholm, Denmark and a Posidonia black shale from Lower Saxony, Germany. The Alum shale is a carbonate free black shale with pyrite and barite, containing 74.4 mu g/g U. The Posidonia shales is a calcareous shale with pyrite but without detectable amounts of barite containing 3.6 mu g/g U. Pyrite oxidized during the tests forming sulfuric acid which lowered the pH on values between 2 and 3 of the extraction fluid from the Alum shale favoring a release of U from the Alum shale to the fluid during the short-term and in the beginning of the long-term experiments. The activity concentration of U-238 is as high as 23.9 mBq/ml in the fluid for those experiments. The release of U and Th into the fluid is almost independent of pressure. The amount of uranium in the European shales is similar to that of the Marcellus Shale in the United States but the daughter product of U-238, the Ra-226 activity concentrations in the experimentally derived leachates from the European shales are quite low in comparison to that found in industrially derived flowback fluids from the Marcellus shale. This difference could mainly be due to missing Cl in the reaction fluid used in our experiments and a lower fluid to solid ratio in the industrial plays than in the experiments due to subsequent fracking and minute cracks from which Ra can easily be released. KW - Unconventional gas production KW - Black shales KW - Flowback KW - Radioactivity KW - NOR KW - Batch experiments Y1 - 2018 U6 - https://doi.org/10.1016/j.jenvrad.2018.05.005 SN - 0265-931X SN - 1879-1700 VL - 190 SP - 122 EP - 129 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Ma, Xuemin A1 - Balazadeh, Salma A1 - Mueller-Roeber, Bernd T1 - Tomato fruit ripening factor NOR controls leaf senescence JF - Journal of experimental botany N2 - NAC transcription factors (TFs) are important regulators of expressional reprogramming during plant development, stress responses, and leaf senescence. NAC TFs also play important roles in fruit ripening. In tomato (Solanum lycopersicum), one of the best characterized NACs involved in fruit ripening is NON-RIPENING (NOR), and the non-ripening (nor) mutation has been widely used to extend fruit shelf life in elite varieties. Here, we show that NOR additionally controls leaf senescence. Expression of NOR increases with leaf age, and developmental as well as dark-induced senescence are delayed in the nor mutant, while overexpression of NOR promotes leaf senescence. Genes associated with chlorophyll degradation as well as senescence-associated genes (SAGs) show reduced and elevated expression, respectively, in nor mutants and NOR overexpressors. Overexpression of NOR also stimulates leaf senescence in Arabidopsis thaliana. In tomato, NOR supports senescence by directly and positively regulating the expression of several senescence-associated genes including, besides others, SlSAG15 and SlSAG113, SlSGR1, and SlYLS4. Finally, we find that another senescence control NAC TF, namely SlNAP2, acts upstream of NOR to regulate its expression. Our data support a model whereby NAC TFs have often been recruited by higher plants for both the control of leaf senescence and fruit ripening. KW - Aging KW - leaf KW - NAC KW - non-ripening KW - NOR KW - senescence KW - tomato KW - transcription factor Y1 - 2019 U6 - https://doi.org/10.1093/jxb/erz098 SN - 0022-0957 SN - 1460-2431 VL - 70 IS - 10 SP - 2727 EP - 2740 PB - Oxford Univ. Press CY - Oxford ER -