| 1. |
- Pärn, J., et al.
(författare)
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Nitrogen-rich organic soils under warm well-drained conditions are global nitrous oxide emission hotspots
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Nitrous oxide (N2O) is a powerful greenhouse gas and the main driver of stratospheric ozone depletion. Since soils are the largest source of N2O, predicting soil response to changes in climate or land use is central to understanding and managing N2O. Here we find that N2O flux can be predicted by models incorporating soil nitrate concentration (NO3 -), water content and temperature using a global field survey of N2O emissions and potential driving factors across a wide range of organic soils. N2O emissions increase with NO3 - and follow a bell-shaped distribution with water content. Combining the two functions explains 72% of N2O emission from all organic soils. Above 5 mg NO3 --N kg-1, either draining wet soils or irrigating well-drained soils increases N2O emission by orders of magnitude. As soil temperature together with NO3 - explains 69% of N2O emission, tropical wetlands should be a priority for N2O management.
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| 2. |
- Mitkevich, Vladimir A., et al.
(författare)
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Thermodynamic Characterization of ppGpp Binding to EF-G or 1F2 and of Initiator tRNA Binding to Free 1F2 in the Presence of GDP, GTP, or ppGpp
- 2010
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Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 402:5, s. 838-846
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Tidskriftsartikel (refereegranskat)abstract
- In addition to their natural substrates GDP and GTP, the bacterial translational GTPases initiation factor (IF) 2 and elongation factor G (EF-G) interact with the alarmone molecule guanosine tetraphosphate (ppGpp), which leads to GTPase inhibition. We have used isothermal titration calorimetry to determine the affinities of ppGpp for IF2 and EF-G at a temperature interval of 5-25 degrees C. We find that ppGpp has a higher affinity for IF2 than for EF-G (1.7-2.8 Q mu M K-d versus 9.1-13.9 mu M K-d at 10-25 degrees C), suggesting that during stringent response in vivo, IF2 is more responsive to ppGpp than to EF-G. We investigated the effects of ppGpp, GDP, and GTP on IF2 interactions with fMet-tRNA(fMet) demonstrating that IF2 binds to initiator tRNA with submicromolar K-d and that affinity is altered by the G nucleotides only slightly. This-in conjunction with earlier reports on IF2 interactions with fMet-tRNA(fMet) in the context of the 30S initiation complex, where ppGpp was suggested to strongly inhibit fMet-tRNA(fMet) binding and GTP was suggested to strongly promote fMet-tRNA(fMet) binding-sheds new light on the mechanisms of the G-nucleotide-regulated fMet-tRNA(fMet) selection.
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| 3. |
- Gefenas, E., et al.
(författare)
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Non-equivalent stringency of ethical review in the Baltic States: a sign of a systematic problem in Europe?
- 2010
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Ingår i: Journal of Medical Ethics. - : BMJ. - 1473-4257 .- 0306-6800. ; 36:7, s. 435-439
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Tidskriftsartikel (refereegranskat)abstract
- We analyse the system of ethical review of human research in the Baltic States by introducing the principle of equivalent stringency of ethical review, that is, research projects imposing equal risks and inconveniences on research participants should be subjected to equally stringent review procedures. We examine several examples of non-equivalence or asymmetry in the system of ethical review of human research: (1) the asymmetry between rather strict regulations of clinical drug trials and relatively weaker regulations of other types of clinical biomedical research and (2) gaps in ethical review in the area of non-biomedical human research where some sensitive research projects are not reviewed by research ethics committees at all. We conclude that non-equivalent stringency of ethical review is at least partly linked to the differences in scope and binding character of various international legal instruments that have been shaping the system of ethical review in the Baltic States. Therefore, the Baltic example could also serve as an object lesson to other European countries which might be experiencing similar problems.
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