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| 35. |
- Costello, David M., et al.
(author)
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Global patterns and controls of nutrient immobilization on decomposing cellulose in riverine ecosystems
- 2022
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In: Global Biogeochemical Cycles. - : John Wiley & Sons. - 0886-6236 .- 1944-9224. ; 36:3
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Journal article (peer-reviewed)abstract
- Microbes play a critical role in plant litter decomposition and influence the fate of carbon in rivers and riparian zones. When decomposing low-nutrient plant litter, microbes acquire nitrogen (N) and phosphorus (P) from the environment (i.e., nutrient immobilization), and this process is potentially sensitive to nutrient loading and changing climate. Nonetheless, environmental controls on immobilization are poorly understood because rates are also influenced by plant litter chemistry, which is coupled to the same environmental factors. Here we used a standardized, low-nutrient organic matter substrate (cotton strips) to quantify nutrient immobilization at 100 paired stream and riparian sites representing 11 biomes worldwide. Immobilization rates varied by three orders of magnitude, were greater in rivers than riparian zones, and were strongly correlated to decomposition rates. In rivers, P immobilization rates were controlled by surface water phosphate concentrations, but N immobilization rates were not related to inorganic N. The N:P of immobilized nutrients was tightly constrained to a molar ratio of 10:1 despite wide variation in surface water N:P. Immobilization rates were temperature-dependent in riparian zones but not related to temperature in rivers. However, in rivers nutrient supply ultimately controlled whether microbes could achieve the maximum expected decomposition rate at a given temperature. Collectively, we demonstrated that exogenous nutrient supply and immobilization are critical control points for decomposition of organic matter.
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| 36. |
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| 37. |
- Kristensen, S. L., et al.
(author)
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Geographic variations in the PARADIGM-HF heart failure trial
- 2016
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In: European heart journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 37:41, s. 3167-3174
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Journal article (peer-reviewed)abstract
- AIMS: The globalization of clinical trials has highlighted geographic variations in patient characteristics, event rates, and treatment effects. We investigated these further in PARADIGM-HF, the largest and most globally representative trial in heart failure (HF) to date. METHODS AND RESULTS: We looked at five regions: North America (NA) 622 (8%), Western Europe (WE) 1680 (20%), Central/Eastern Europe/Russia (CEER) 2762 (33%), Latin America (LA) 1413 (17%), and Asia-Pacific (AP) 1487 (18%). Notable differences included: WE patients (mean age 68 years) and NA (65 years) were older than AP (58 years) and LA (63 years) and had more coronary disease; NA and CEER patients had the worst signs, symptoms, and functional status. North American patients were the most likely to have a defibrillating-device (53 vs. 2% AP) and least likely prescribed a mineralocorticoid receptor antagonist (36 vs. 61% LA). Other evidence-based therapies were used most frequently in NA and WE. Rates of the primary composite outcome of cardiovascular (CV) death or HF hospitalization (per 100 patient-years) varied among regions: NA 13.5 (95% CI 11.7-15.6), WE 9.6 (8.6-10.6), CEER 12.3 (11.4-13.2), LA 11.2 (10.0-12.5), and AP 12.5 (11.3-13.8). After adjustment for prognostic variables, relative to NA, the risk of CV death was higher in LA and AP and the risk of HF hospitalization lower in WE. The benefit of sacubitril/valsartan was consistent across regions. CONCLUSION: There were many regional differences in PARADIGM-HF, including in age, symptoms, comorbidity, background therapy, and event-rates, although these did not modify the benefit of sacubitril/valsartan. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01035255.
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| 39. |
- McMurray, J., et al.
(author)
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A putative placebo analysis of the effects of LCZ696 on clinical outcomes in heart failure
- 2015
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In: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 36:7, s. 434-439
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Journal article (peer-reviewed)abstract
- AIMS: Although active-controlled trials with renin-angiotensin inhibitors are ethically mandated in heart failure with reduced ejection fraction, clinicians and regulators often want to know how the experimental therapy would perform compared with placebo. The angiotensin receptor-neprilysin inhibitor LCZ696 was compared with enalapril in PARADIGM-HF. We made indirect comparisons of the effects of LCZ696 with putative placebos. METHODS AND RESULTS: We used the treatment-arm of the Studies Of Left Ventricular Dysfunction (SOLVD-T) as the reference trial for comparison of an ACE inhibitor to placebo and the Candesartan in Heart failure: Assessment of Reduction in Mortality and morbidity-Alternative trial (CHARM-Alternative) as the reference trial for comparison of an ARB to placebo. The hazard ratio of LCZ696 vs. a putative placebo was estimated through the product of the hazard ratio of LCZ696 vs. enalapril (active-control) and that of the historical active-control (enalapril or candesartan) vs. placebo. For the primary composite outcome of cardiovascular death or heart failure hospitalization in PARADIGM-HF, the relative risk reduction with LCZ696 vs. a putative placebo from SOLVD-T was 43% (95%CI 34-50%; P < 0.0001) with similarly large effects on cardiovascular death (34%, 21-44%; P < 0.0001) and heart failure hospitalization (49%, 39-58%; P < 0.0001). For all-cause mortality, the reduction compared with a putative placebo was 28% (95%CI 15-39%; P < 0.0001). Putative placebo analyses based on CHARM-Alternative gave relative risk reductions of 39% (95%CI 27-48%; P < 0.0001) for the composite outcome of cardiovascular death or heart failure hospitalization, 32% (95%CI 16-45%; P < 0.0001) for cardiovascular death, 46% (33-56%; P < 0.0001) for heart failure hospitalization, and 26% (95%CI 11-39%; P < 0.0001) for all-cause mortality. CONCLUSION: These indirect comparisons of LCZ696 with a putative placebo show that the strategy of combined angiotensin receptor blockade and neprilysin inhibition led to striking reductions in cardiovascular and all-cause mortality, as well as heart failure hospitalization. These benefits were obtained even though LCZ696 was added to comprehensive background beta-blocker and mineralocorticoid receptor antagonist therapy.
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