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- Attermeyer, Katrin, et al.
(författare)
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Carbon dioxide fluxes increase from day to night across European streams
- 2021
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Ingår i: Communications Earth & Environment. - : Springer Nature. - 2662-4435. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- Globally, inland waters emit over 2 Pg of carbon per year as carbon dioxide, of which the majority originates from streams and rivers. Despite the global significance of fluvial carbon dioxide emissions, little is known about their diel dynamics. Here we present a large-scale assessment of day- and night-time carbon dioxide fluxes at the water-air interface across 34 European streams. We directly measured fluxes four times between October 2016 and July 2017 using drifting chambers. Median fluxes are 1.4 and 2.1mmolm(-2) h(-1) at midday and midnight, respectively, with night fluxes exceeding those during the day by 39%. We attribute diel carbon dioxide flux variability mainly to changes in the water partial pressure of carbon dioxide. However, no consistent drivers could be identified across sites. Our findings highlight widespread day-night changes in fluvial carbon dioxide fluxes and suggest that the time of day greatly influences measured carbon dioxide fluxes across European streams. Diel patterns can greatly impact total stream carbon dioxide emissions, with 39% greater carbon dioxide flux during the night-time relative to the day-time, according to a study of 34 streams across Europe.
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| 2. |
- Hinrichsen, F., et al.
(författare)
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Microbial regulation of hexokinase 2 links mitochondrial metabolism and cell death in colitis
- 2021
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Ingår i: Cell Metabolism. - : Elsevier BV. - 1550-4131. ; 33:12
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Tidskriftsartikel (refereegranskat)abstract
- Hexokinases (HK) catalyze the first step of glycolysis limiting its pace. HK2 is highly expressed in gut epithelium, contributes to immune responses, and is upregulated during inflammation. We examined the microbial regulation of HK2 and its impact on inflammation using mice lacking HK2 in intestinal epithelial cells (Hk2(Delta IEC)). Hk2(Delta IEC) mice were less susceptible to acute colitis. Analyzing the epithelial transcriptome from Hk2(Delta IEC) mice during colitis and using HK2-deficient intestinal organoids and Caco-2 cells revealed reduced mitochondrial respiration and epithelial cell death in the absence of HK2. The microbiota strongly regulated HK2 expression and activity. The microbially derived short-chain fatty acid (SCFA) butyrate repressed HK2 expression via histone deacetylase 8 (HDAC8) and reduced mitochondrial respiration in wild-type but not in HK2-deficient Caco-2 cells. Butyrate supplementation protected wild-type but not Hk2(Delta IEC) mice from colitis. Our findings define a mechanism how butyrate promotes intestinal homeostasis and suggest targeted HK2-inhibition as therapeutic avenue for inflammation.
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| 3. |
- Johansson, Magnus C, 1954, et al.
(författare)
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Increased arterial stiffness and reduced left ventricular long-axis function in patients recovered from peripartum cardiomyopathy
- 2021
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Ingår i: Clinical Physiology and Functional Imaging. - : Wiley. - 1475-0961 .- 1475-097X. ; 41:1, s. 95-102
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Tidskriftsartikel (refereegranskat)abstract
- Background Peripartum cardiomyopathy (PPCM) is idiopathic pregnancy-associated heart failure (HF) with reduced left ventricular ejection fraction (LVEF). We aimed to assess arterial stiffness and left ventricular (LV) function in women recovered from PPCM compared with controls. Methods Twenty-two PPCM patients were compared with 15 age-matched controls with previous uncomplicated pregnancies. Eleven of the patients were at inclusion in the study recovered and off medication since at least 6 months and still free from cardiovascular symptoms with normal LVEF and normal NT-proBNP. All underwent echocardiography, including LV strain, left atrial (LA) reservoir strain and tissue Doppler early diastolic velocity (e ') and non-invasive assessment for arterial stiffness and central aortic systolic blood pressure (AoBP) at rest and immediately postexercise. Results The patients off medication showed alterations compared with controls. AoBP was higher (120 +/- 9 mm Hg vs. 104 +/- 13 mm Hg; p = .001), a difference which persisted postexercise. The arterial elastance was higher (1.9 +/- 0.4 mm Hg/ml vs. 1.3 +/- 0.2 mm Hg/ml; p < .001), while there were lower e ' septal (8.9 +/- 1.7 cm/s vs. 11.0 +/- 1.1 cm/s; p = 0. 002), LV global strain (18.7 +/- 3.9% vs. 23.1 +/- 1.6%; p = .004) and LA reservoir strain (24.8 +/- 9.1% vs. 37.7 +/- 6.3%; p = .002). Conclusions Compared with healthy controls, PPCM patients considered recovered and off medication had increased arterial stiffness, decreased LV longitudinal function and reduced LA function.
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