| 1. |
- Sarneel, Judith M., et al.
(author)
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Reading tea leaves worldwide : decoupled drivers of initial litter decomposition mass-loss rate and stabilization
- 2024
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In: Ecology Letters. - : John Wiley & Sons. - 1461-023X .- 1461-0248. ; 27:5
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Journal article (peer-reviewed)abstract
- The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.
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| 2. |
- Sarneel, Judith M., et al.
(author)
-
Reading tea leaves worldwide: Decoupled drivers of initial litter decomposition mass-loss rate and stabilization
- 2024
-
In: ECOLOGY LETTERS. - : John Wiley & Sons. - 1461-023X .- 1461-0248. ; 27:5
-
Journal article (peer-reviewed)abstract
- The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.
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| 3. |
- Demidova, M. M., et al.
(author)
-
Prolonged Tpeak-Tend interval is associated with ventricular fibrillation during reperfusion in ST-elevation myocardial infarction
- 2019
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In: International Journal of Cardiology. - : Elsevier BV. - 0167-5273. ; 280, s. 80-83
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Journal article (peer-reviewed)abstract
- Aim: Ventricular fibrillation (VF) during reperfusion in ST-elevation myocardial infarction (STEMI) is associated with increased in-hospital mortality. Dispersion of ventricular repolarization contributes to ventricular vulnerability during ischemia. Tpeak-Tend interval was proposed as a ventricular repolarization dispersion marker, however its value for prediction of reperfusion VF remains uncertain. We aimed to assess whether Tpeak-Tend before PCI in STEMI is associated with reperfusion VF. Methods: STEMI patients admitted for primary PCI were retrospectively assessed for VF during reperfusion. Pre-PCI ECGs recorded in 40 patients with reperfusion VF (rVF group; age 65 ± 13 years, 80% male) were compared with 374 consecutive patients without reperfusion arrhythmias (No-rVF group; age 67 ± 12 years; 68% male). Digital ECGs were automatically processed and Tpeak-Tend interval computed on a per-lead basis. The global Tpeak-Tend was calculated between the earliest Tpeak and the latest Tend in any lead, and tested for association with reperfusion VF using logistic regression analysis. Results: The leftward shift of Tpeak toward QRS complex in ischemic leads resulted in Tpeak-Tend prolongation. Global Tpeak-Tend in rVF group was higher than in No-rVF group (142 ± 24 vs 130 ± 27 ms; p = 0.007). Global Tpeak-Tend ≥ 131 ms predicted reperfusion VF (OR = 3.41; 95% CI 1.66–7.04; p = 0.001) and remained a significant predictor of reperfusion VF in multivariable analysis. Conclusion: Tpeak-Tend interval before PCI in STEMI was an independent predictor of reperfusion VF. Our findings warrants further research aimed at prospective validation of Tpeak-Tend as a marker of periprocedural arrhythmic risk.
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| 4. |
- Tsvetkova, Alena S., et al.
(author)
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Melatonin Prevents Early but Not Delayed Ventricular Fibrillation in the Experimental Porcine Model of Acute Ischemia
- 2020
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1422-0067. ; 22:1
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Journal article (peer-reviewed)abstract
- Antiarrhythmic effects of melatonin have been demonstrated ex vivo and in rodent models, but its action in a clinically relevant large mammalian model remains largely unknown. Objectives of the present study were to evaluate electrophysiological and antiarrhythmic effects of melatonin in a porcine model of acute myocardial infarction. Myocardial ischemia was induced by 40-min coronary occlusion in 25 anesthetized pigs. After ischemia onset, 12 animals received melatonin (4 mg/kg). 48 intramyocardial electrograms were recorded from left ventricular wall and interventricular septum (IVS). In each lead, activation time (AT) and repolarization time (RT) were determined. During ischemia, ATs and dispersion of repolarization (DOR = RTmax - RTmin) increased reaching maximal values by 3-5 and 20-25 min, respectively. Ventricular fibrillation (VF) incidence demonstrated no relations to redox state markers and was associated with increased DOR and delayed ATs (specifically, in an IVS base, an area adjacent to the ischemic zone) (p = 0.031). Melatonin prevented AT increase in the IVS base, (p < 0.001) precluding development of early VF (1-5 min, p = 0.016). VF occurrence in the delayed phase (17-40 min) where DOR was maximal was not modified by melatonin. Thus, melatonin-related enhancement of activation prevented development of early VF in the myocardial infarction model.
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