| 1. |
- Vukusic, Kristina, 1979, et al.
(författare)
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The Atrioventricular Junction: A Potential Niche Region for Progenitor Cells in the Adult Human Heart
- 2019
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Ingår i: Stem Cells and Development. - : Mary Ann Liebert Inc. - 1547-3287 .- 1557-8534. ; 28:16, s. 1078-1088
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Tidskriftsartikel (refereegranskat)abstract
- A stem cell niche is a microenvironment where stem cells reside in a quiescent state, until activated. In a previous rat model, we combined 5-bromo-2-deoxy-uridine labeling with activation of endogenous stem cells by physical exercise and revealed a distinct region, in the atrioventricular junction (AVj), with features of a stem cell niche. In this study, we aim to investigate whether a similar niche exists in the human heart. Paired biopsies from AVj and left ventricle (LV) were collected both from explanted hearts of organ donors, not used for transplantation (N = 7) and from severely failing hearts from patients undergoing heart transplantation (N = 7). Using antibodies, we investigated the expression of stem cell, hypoxia, proliferation and migration biomarkers. In the collagen-dense region of the AVj in donor hearts, progenitor markers, MDR1, SSEA4, ISL1, WT1, and hypoxia marker, HIF1-alpha, were clearly detected. The expression gradually decreased with distance from the valve. At the myocardium border in the AVj costaining of the proliferation marker Ki67 with cardiomyocyte nuclei marker PCM1 and cardiac Troponin-T (cTnT) indicated proliferation of small cardiomyocytes. In the same site we also detected ISL1(+)/WT1(+)/cTnT cells. In addition, heterogeneity in cardiomyocyte sizes was noted. Altogether, these findings indicate different developmental stages of cardiomyocytes below the region dense in stem cell marker expression. In patients suffering from heart failure the AVj region showed signs of impairment generally displaying much weaker or no expression of progenitor markers. We describe an anatomic structure in the human hearts, with features of a progenitor niche that coincided with the same region previously identified in rats with densely packed cells expressing progenitor and hypoxia markers. The data provided in this study indicate that the adult heart contains progenitor cells and that AVj might be a specific niche region from which the progenitors migrate at the time of regeneration.
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| 2. |
- Bergkvist, Lisa, et al.
(författare)
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Carbon Sequestration Potential f Agroforestry Systems For Phytoremediation In Chinandega, Nicaragua
- 2018
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Ingår i: Linnaeus Eco-Tech 2018. ; , s. 211-211
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Greenhouse gases in the atmosphere have increased to earlier unrecorded levels, causing global climate change that increases GMT and threaten ecosystems and livelihoods. IPCC report suggest that agroforestry offers considerable carbon sequestration (c seq.) potential, especially for developing countries. The purpose of this study is to estimate the c seq. potential in different agroforestry systems suitable in Chinandega, Nicaragua - a deforested region where the ground is polluted by toxaphene and other POP:s. Three scenarios where studied; Shading system using Tectona grandis and Pogostemon cablin; Alley cropping using Erythrina poeppigiana and Ricinus communis and Silvopasture using Cordia alliodora and Brachiaria ruziziensis, the last scenario being divided into two subscenarios; unmanaged (grazed) and managed (harvested) grass. Calculations were performed using the modelling program CO2FIX v. 3.2, with a runtime of 100 years and assuming deforested area with no previous land use. Results show a significantly higher c seq. potential in Shading system (168/217 MgC/ha). Alley cropping yields 71 MgC/ha and Silvopasture results in 80/84 MgC/ha unmanaged and 65/70 MgC/ha managed. The higher number includes products from harvest. All scenarios show fluctuations over time due to thinning and harvesting practices. Phytoremediation potential of POPs has been shown in Ricinus communis and grass species. Soil c seq. is especially important to consider in longterm scenarios as this c seq. can be sustained over longer time. The inclusion of crop residue, the effect of grazing animals or changes in density of trees and crops and environmental fate of the toxic compounds need further assessment before considering large scale applications. Agroforestry practices could contribute to several benefits, including climate change mitigation and phytoremediation.
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| 3. |
- Sandstedt, Mikael, 1990, et al.
(författare)
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Intracellular flow cytometry may be combined with good quality and high sensitivity RT-qPCR analysis.
- 2015
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Ingår i: Cytometry. Part A : the journal of the International Society for Analytical Cytology. - : Wiley. - 1552-4930. ; 87:12, s. 1079-1089
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Tidskriftsartikel (refereegranskat)abstract
- Flow cytometry (FCM) has become a well-established method for analysis of both intracellular and cell-surface proteins, while quantitative RT-PCR (RT-qPCR) is used to determine gene expression with high sensitivity and specificity. Combining these two methods would be of great value. The effects of intracellular staining on RNA integrity and RT-qPCR sensitivity and quality have not, however, been fully examined. We, therefore, intended to assess these effects further. Cells from the human lung cancer cell line A549 were fixed, permeabilized and sorted by FCM. Sorted cells were analyzed using RT-qPCR. RNA integrity was determined by RNA quality indicator analysis. A549 cells were then mixed with cells of the mouse cardiomyocyte cell line HL-1. A549 cells were identified by the cell surface marker ABCG2, while HL-1 cells were identified by intracellular cTnT. Cells were sorted and analyzed by RT-qPCR. Finally, cell cultures from human atrial biopsies were used to evaluate the effects of fixation and permeabilization on RT-qPCR analysis of nonimmortalized cells stored prior to analysis by FCM. A large amount of RNA could be extracted even when cells had been fixed and permeabilized. Permeabilization resulted in increased RNA degradation and a moderate decrease in RT-qPCR sensitivity. Gene expression levels were also affected to a moderate extent. Sorted populations from the mixed A549 and HL-1 cell samples showed gene expression patterns that corresponded to FCM data. When samples were stored before FCM sorting, the RT-qPCR analysis could still be performed with high sensitivity and quality. In summary, our results show that intracellular FCM may be performed with only minor impairment of the RT-qPCR sensitivity and quality when analyzing sorted cells; however, these effects should be considered when comparing RT-qPCR data of not fixed samples with those of fixed and permeabilized samples. © 2015 International Society for Advancement of Cytometry.
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| 4. |
- Benediktsson, Ívar Örn, et al.
(författare)
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Progressive formation of modern drumlins at Múlajökull, Iceland: stratigraphical and morphological evidence
- 2016
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Ingår i: Boreas. - : Wiley. - 0300-9483 .- 1502-3885. ; 45, s. 567-583
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Tidskriftsartikel (refereegranskat)abstract
- © 2016 Collegium Boreas. Published by John Wiley & Sons Ltd The drumlin field at Múlajökull, Iceland, is considered to be an active field in that partly and fully ice-covered drumlins are being shaped by the current glacier regime. We test the hypothesis that the drumlins form by a combination of erosion and deposition during successive surge cycles. We mapped and measured 143 drumlins and studied their stratigraphy in four exposures. All exposures reveal several till units where the youngest till commonly truncates older tills on the drumlin flanks and proximal slope. Drumlins inside a 1992 moraine are relatively long and narrow whereas drumlins outside the moraine are wider and shorter. A conceptual model suggests that radial crevasses create spatial heterogeneity in normal stress on the bed so that deposition is favoured beneath crevasses and erosion in adjacent areas. Consequently, the crevasse pattern of the glacier controls the location of proto-drumlins. A feedback mechanism leads to continued crevassing and increased sedimentation at the location of the proto-drumlins. The drumlin relief and elongation ratio increases as the glacier erodes the sides and drapes a new till over the landform through successive surges. Our observations of this only known active drumlin field may have implications for the formation and morphological evolution of Pleistocene drumlin fields with similar composition, and our model may be tested on modern drumlins that may become exposed upon future ice retreat.
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| 5. |
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| 6. |
- Haller, Henrik, 1977-, et al.
(författare)
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Application of ecological engineering within the framework for strategic sustainable development for design of appropriate soil bioremediation technologies in marginalized regions
- 2018
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Ingår i: Journal of Cleaner Production. - : Elsevier. - 0959-6526 .- 1879-1786. ; 172, s. 2415-2424
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Tidskriftsartikel (refereegranskat)abstract
- This study explores a systematic strategy to design appropriate bioremediation projects for marginalized regions that have the potential to contribute to sustainable development in that region. Ecological Engineering (EE) is of particular value for the development of appropriate bioremediation technology for such regions but a stricter planning tool than provided by EE itself, is also needed when the goal of the project goes beyond remediation targets. The Framework for Strategic Sustainable Development (FSSD) applies basic principles for sustainability and includes a stepwise strategic planning mechanism for their application. The inclusion of EE within the FSSD may steer soil bioremediation projects in rural areas in developing countries and sparsely populated regions in industrialized countries towards sustainability. The utility of the approach was tested on two cases of soil pollution in marginalized regions: the Chinandega region in Nicaragua (pesticide polluted agricultural soil) and a former filling station (diesel polluted residual area) in Gäddede, northern Sweden. The study demonstrates how the inclusion of the EE key concepts within the FSSD may increase the utility of EE for strategic sustainable development within the region. No difficulties in terms of conflicting suggestions were found in the proposed integrated approach; the two tools were found to contribute on different aspects to provide support to project management and decision making.
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| 7. |
- Haller, Henrik, 1977-, et al.
(författare)
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Bioaccumulation and translocation of field-weathered toxaphene and other persistent organic pollutants in three cultivars of amaranth (A. cruentus ‘R127 México’, A. cruentus ‘Don León’ y A. caudatus ‘CAC 48 Perú’) – A field study from former cotton fields in Chinandega, Nicaragua
- 2018
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Ingår i: Ecological Engineering. - : Elsevier BV. - 0925-8574 .- 1872-6992. ; 121, s. 65-71
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Tidskriftsartikel (refereegranskat)abstract
- Soils polluted by persistent organic pollutants threatens habitats for plants and animals as well as basic human needs such as food security and provision of potable water. Toxaphene is a persistent organic pollutant that was heavily used as a pesticide in Central America, Brazil, Soviet Union etc. until it was banned in 1993. The objective of this study was to determine the bioaccumulation and translocation characteristics of three different cultivars of amaranth in soils contaminated with field-weathered toxaphene and other POPs in former cotton fields in Chinandega, Nicaragua to identify safety issues for human consumption and/or potential for phytoremediation. The concentration of toxaphene and other POPs in the edible parts of the amaranth (leaves and seeds) exceeded the maximum residue level for human consumption established by the European Union for most of the tested compounds. Concentrations of toxaphene congeners and other POPs were found in all vegetative organs. Many substances were accumulated to concentrations more than 10 times higher than in the soil. Of the three cultivars, A. caudatus 'CAC48 Perú' and A. cruentus 'Don Leon' presented the highest average BAF. None of the 3 cultivars can be considered a panacea hyperaccumulator for either toxaphene alone or in conjunction with other POPs but since many agricultural soils comprise a range of different contaminants, the broad-spectrum bioaccumulating capacity of amaranth can make it an interesting candidate for phytoremediation.
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| 8. |
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| 9. |
- Haller, Henrik, 1977-
(författare)
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Soil Remediation and Sustainable Development : Creating Appropriate Solutions for Marginalized Regions
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The scope of this doctoral thesis is appropriate soil remediation methods for marginalized regions that go beyond pollution reduction targets and include strategies to support sustainable development. Contaminated soil from industrial or agricultural activities poses potential health threats to animals and humans and also threatens economic systems by making land unsuitable for agriculture and other economic purposes. Remediation of contaminated sites in marginalized regions such as rural areas in developing countries or sparsely populated regions in industrialized countries, need strategies that meet a different set of criteria compared to urban industrial sites in order to be appropriate. A pilot-scale experimental station was built to assess the feasibility of using organic by-products to enhance the degradation of diesel fuel. It was demonstrated that bioremediation based on the use of readily available organic by-products as amendments or phytoremediation based on locally present plants can be appropriate choices of technology in marginalized regions. Systematic sustainability assessments of the regions local environmental and social context of the contaminated site are necessary to design appropriate bioremediation projects. The inclusion of ecological engineering into the framework for strategic sustainable development, as an integrated planning guide, was demonstrated by two case studies to give valuable input to the strategic process when bioremediation is used as a tool to reach sustainability goals. Results from pilot-scale experiments confirm that whey can significantly increase the degradation rate of diesel fuel, but the slow overall degradation rates due to the high clay content in ultisol (a common tropical soil) could be a considerable constraint for efficient pollutant removal in full scale applications. Results from an experiment in soil cylinders show that the vertical migration of added microorganisms was limited in dense soils. Three species of amaranth tested in the field experiment effectively bioaccumulated toxaphene and other persistent organic pollutants which make them potentially interesting candidates for phytoremediation in the region.
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| 10. |
- Ingolfsson, Olafur, et al.
(författare)
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Glacial geological studies of surge-type glaciers in Iceland — Research
- 2016
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Ingår i: Earth-Science Reviews. - : Elsevier BV. - 0012-8252. ; 152, s. 37-69
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Tidskriftsartikel (refereegranskat)abstract
- Surging glaciers are potential analogues for land-terminating palaeo-ice streams and surging ice sheet lobes, and research on surge-type glaciers is important for understanding the causal mechanisms of modern and past ice sheet instabilities. The geomorphic signatures left by the Icelandic surge-type glaciers vary and range from glaciotectonic end moraines formed by folding and thrusting, crevasse-squeeze ridges, concertina eskers, drumlins and fluted forefields, to extensive dead-ice fields and even drift sheets where fast ice-flow indicators are largely missing. We outline some outstanding research questions and review case studies from the surge-type outlets of Brúarjökull, Eyjabakkajökull and Tungnaárjökull (Vatnajökull ice cap), Múlajökull and Sátujökull (Hofsjökull ice cap), Hagafellsjökull and Suðurjökull (Langjökull ice cap), Kaldalónsjökull, Leirufjarðarjökull and Reykjarfjarðarjökull (Drangajökull ice cap), as well as the surge-type cirque glaciers in northern Iceland. We review the current understanding of how rapid ice flow is sustained throughout the surge, the processes that control the development of the surge-type glacier landsystem and the geological evidence of surges found in sediments and landforms. We also examine if it is possible to reconstruct past surge flow rates from glacial landforms and sediments and scale-up present-day surge processes, landforms and landsystems as modern analogues to past ice streams. Finally,we also examine if there is a climate/mass-balance control on surge initiation, duration and frequency.
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