| 1. |
- Bergmann, Olaf, et al.
(författare)
-
Dynamics of Cell Generation and Turnover in the Human Heart.
- 2015
-
Ingår i: Cell. - : Elsevier BV. - 1097-4172 .- 0092-8674. ; 161:7, s. 1566-1575
-
Tidskriftsartikel (refereegranskat)abstract
- The contribution of cell generation to physiological heart growth and maintenance in humans has been difficult to establish and has remained controversial. We report that the full complement of cardiomyocytes is established perinataly and remains stable over the human lifespan, whereas the numbers of both endothelial and mesenchymal cells increase substantially from birth to early adulthood. Analysis of the integration of nuclear bomb test-derived (14)C revealed a high turnover rate of endothelial cells throughout life (>15% per year) and more limited renewal of mesenchymal cells (<4% per year in adulthood). Cardiomyocyte exchange is highest in early childhood and decreases gradually throughout life to <1% per year in adulthood, with similar turnover rates in the major subdivisions of the myocardium. We provide an integrated model of cell generation and turnover in the human heart. VIDEO ABSTRACT.
|
|
| 2. |
|
|
| 3. |
- Pangala, Sunitha R., et al.
(författare)
-
Large emissions from floodplain trees close the Amazon methane budget
- 2017
-
Ingår i: Nature. - : NATURE PUBLISHING GROUP. - 0028-0836 .- 1476-4687. ; 552:7684, s. 230-
-
Tidskriftsartikel (refereegranskat)abstract
- Wetlands are the largest global source of atmospheric methane (CH4)(1), a potent greenhouse gas. However, methane emission inventories from the Amazon floodplain(2,3), the largest natural geographic source of CH4 in the tropics, consistently underestimate the atmospheric burden of CH4 determined via remote sensing and inversion modelling(4,5), pointing to a major gap in our understanding of the contribution of these ecosystems to CH4 emissions. Here we report CH4 fluxes from the stems of 2,357 individual Amazonian floodplain trees from 13 locations across the central Amazon basin. We find that escape of soil gas through wetland trees is the dominant source of regional CH4 emissions. Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests(6) and tropical peat swamp forests(7), representing the largest non-ebullitive wetland fluxes observed. Emissions from trees had an average stable carbon isotope value (delta C-13) of -66.2 +/- 6.4 per mil, consistent with a soil biogenic origin. We estimate that floodplain trees emit 15.1 +/- 1.8 to 21.2 +/- 2.5 teragrams of CH4 a year, in addition to the 20.5 +/- 5.3 teragrams a year emitted regionally from other sources. Furthermore, we provide a topdown regional estimate of CH4 emissions of 42.7 +/- 5.6 teragrams of CH4 a year for the Amazon basin, based on regular vertical lower-troposphere CH4 profiles covering the period 2010-2013. We find close agreement between our top-down and combined bottom-up estimates, indicating that large CH4 emissions from trees adapted to permanent or seasonal inundation can account for the emission source that is required to close the Amazon CH4 budget. Our findings demonstrate the importance of tree stem surfaces in mediating approximately half of all wetland CH4 emissions in the Amazon floodplain, a region that represents up to one-third of the global wetland CH4 source when trees are combined with other emission sources.
|
|
| 4. |
- Quadra, Gabrielle R., et al.
(författare)
-
Environmental Risk of Metal Contamination in Sediments of Tropical Reservoirs
- 2019
-
Ingår i: Bulletin of Environmental Contamination and Toxicology. - : Springer Science and Business Media LLC. - 0007-4861 .- 1432-0800. ; 103:2, s. 292-301
-
Tidskriftsartikel (refereegranskat)abstract
- Reservoir sediment can work as both sink and source for contaminants. Once released into the water column, contaminants can be toxic to biota and humans. We investigate potential ecological risk to benthic organisms by metals contamination in six reservoirs in Southeast Brazil. Results of the bioavailable fraction of copper (Cu), chromium (Cr), cadmium (Cd), lead (Pb), zinc (Zn), and iron (Fe) in sediment samples are presented. Considering Cu, Cd, and Zn concentrations, about 6% of the samples exceeded the threshold effect levels of sediment quality guidelines. The comparison to sediment quality guidelines is conservative because we used a moderate metal extraction. Control of contaminant sources in these reservoirs is key because they are sources of water and food. The mixture toxicity assessment showed an increased incidence of toxicity to aquatic organisms showing that mixture toxicity should be taken into account in sediment assessment criteria.
|
|
| 5. |
- Uddman, Rolf, et al.
(författare)
-
Neurotransmitter candidates in the vomeronasal organ of the rat.
- 2007
-
Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 127:9, s. 952-956
-
Tidskriftsartikel (refereegranskat)abstract
- Conclusion: The rich supply of nerve fibres containing neurotransmitters, particularly those containing SP and CGRP, is suggested to be a prerequisite for the recognition of chemical irritants as part of a chemical sense. Objective: The present study was designed to examine the distribution of different neurotransmitter candidates in the vomeronasal organ (VNO) of rats. Materials and methods: The distribution of neurotransmitter candidates was studied in the vomeronasal organ of the rat using immunocytochemistry. Results: The neuronal marker protein gene product 9.5 revealed a very rich supply of nerve fibres within and beneath the sensory epithelium, around blood vessels and glands. A moderate supply of nerve fibres containing tyrosine hydroxylase and neuropeptide Y was mostly seen close to blood vessels. Numerous nerve fibres containing nitric oxide synthase and vasoactive intestinal peptide were seen around blood vessels and in the subepithelial layer, with occasional fibres within the epithelium. Only few fibres located in the subepithelial layer contained pituitary adenylate cyclase activating peptide. Nerve fibres containing substance P and in particular calcitonin gene-related peptide were abundant in and beneath the epithelium and scattered in the submucosal layers around blood vessels.
|
|
| 6. |
- Warrant, Eric, et al.
(författare)
-
A Night Vision Algorithm Inspired by the Visual System of a Nocturnal Bee
- 2012
-
Ingår i: Biomimetics in Photonics. - : Taylor & Francis. - 9781439877463 - 9781439877470 ; , s. 166-185
-
Bokkapitel (refereegranskat)abstract
- The diversity of different life-forms, their conquest of virtually all available habitats, and their seemingly limitless ability to adapt to new ecological challenges show that structural and physiological specializations of a few basic building plans uniquely match plants and animals to the specific lives they lead.
|
|
