| 1. |
- Moros, Matthias, et al.
(författare)
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Towards an event stratigraphy for Baltic Sea sediments deposited since AD 1900 : approaches and challenges
- 2017
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Ingår i: Boreas. - : Wiley. - 0300-9483 .- 1502-3885. ; 46:1, s. 129-142
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Tidskriftsartikel (refereegranskat)abstract
- Reconstructions of environmental changes at sub-decadal to decadal resolution based on central Baltic Sea sediments rely on accurate and precise high-resolution sediment depth/age relationships. A model chronology for Baltic Sea sediments is presented here based on established historical records of anthropogenic radionuclides (Cs-137/Am-241/bomb(14)C), polychlorinated biphenyls (PCBs), lead (Pb) and stable lead isotope (Pb-206/207 ratios), and radionuclide Pb-210 and C-14 decay dating methods. Marker horizons consisting of chemical precipitates formed by documented Major Baltic Inflow (MBIs) events and an extended diatom bloom period were also integrated into the model. The main time markers in Baltic Sea sediments that formed during the last 120years were the following: (i) the deepest observation of Pb-210(unsupp.) (marking the Pb-210 dating horizon) and departure of Hg from natural background levels at c.AD 1900; (ii) first detectable presence of PCBs at AD 1935; (iii) radionuclide production (i.e. Am-241) due to nuclear weapons testing between AD 1954 and AD 1975, with a peak in AD 1963; (iv) maximum heavy metal and PCB concentrations in the AD 1960s/1970s; (v) the Chernobyl nuclear accident in AD 1986 as a sharp Cs-137 increase; (vi) exceptionally strong diatom blooms with a massive diatom layer found in the Eastern Gotland Basin in AD 1988-1990; and (vii) characteristic manganese-carbonate layers in the deeper central basins formed by MBIs in AD 1993 and AD 2003. A precise and accurate sediment depth/age relationship can only be achieved in restricted areas of the Baltic Sea where continuous sedimentation has prevailed and there has been limited postdepositional disturbance. We demonstrate that parallel Hg and Cs-137 measurements can be used to assess the quality of sediment sequences for high-resolution environmental reconstructions. We show examples of sediment profiles that conform to the historical record, and examples from Western Baltic Sea areas where it appears to be impossible to establish accurate geochronologies.
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| 2. |
- Perez-Valera, Mario, et al.
(författare)
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Angiotensin-Converting Enzyme 2 (SARS-CoV-2 receptor) expression in human skeletal muscle
- 2021
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Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : John Wiley & Sons. - 0905-7188 .- 1600-0838. ; 31:12, s. 2249-2258
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Tidskriftsartikel (refereegranskat)abstract
- The study aimed to determine the levels of skeletal muscle Angiotensin-Converting Enzyme 2 (ACE2, the SARS-CoV-2 receptor) protein expression in men and women and assess whether ACE2 expression in skeletal muscle is associated with cardiorespiratory fitness and adiposity. The level of ACE2 in vastus lateralis muscle biopsies collected in previous studies from 170 men (age:19-65 yrs, weight:56-137 kg, BMI:23-44) and 69 women (age:18-55 yrs, weight:41-126 kg, BMI:22-39) was analysed in duplicate by western blot. VO2max was determined by ergospirometry and body composition by DXA. ACE2 protein expression was 1.8-fold higher in women than men (p=0.001, n=239). This sex difference disappeared after accounting for the percentage of body fat (fat %), VO2max per kg of legs lean mass (VO2max-LLM) and age (p=0.47). Multiple regression analysis showed that the fat % (β=0.47) is the main predictor of the variability in ACE2 protein expression in skeletal muscle, explaining 5.2 % of the variance. VO2max-LLM had also predictive value (β=0.09). There was a significant fat % by VO2max-LLM interaction, such that for subjects with low fat %, VO2max-LLM was positively associated with ACE2 expression while as fat % increased the slope of the positive association between VO2max-LLM and ACE2 was reduced. In conclusion, women express higher amounts of ACE2 in their skeletal muscles than men. This sexual dimorphism is mainly explained by sex differences in fat % and cardiorespiratory fitness. The percentage of body fat is the main predictor of the variability in ACE2 protein expression in human skeletal muscle.
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