| 1. |
- Grill, G., et al.
(författare)
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Mapping the world's free-flowing rivers
- 2019
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 569:7755, s. 215-221
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Tidskriftsartikel (refereegranskat)abstract
- Free-flowing rivers (FFRs) support diverse, complex and dynamic ecosystems globally, providing important societal and economic services. Infrastructure development threatens the ecosystem processes, biodiversity and services that these rivers support. Here we assess the connectivity status of 12 million kilometres of rivers globally and identify those that remain free-flowing in their entire length. Only 37 per cent of rivers longer than 1,000 kilometres remain free-flowing over their entire length and 23 per cent flow uninterrupted to the ocean. Very long FFRs are largely restricted to remote regions of the Arctic and of the Amazon and Congo basins. In densely populated areas only few very long rivers remain free-flowing, such as the Irrawaddy and Salween. Dams and reservoirs and their up- and downstream propagation of fragmentation and flow regulation are the leading contributors to the loss of river connectivity. By applying a new method to quantify riverine connectivity and map FFRs, we provide a foundation for concerted global and national strategies to maintain or restore them.
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| 2. |
- Sepehri, Sobhan, 1986, et al.
(författare)
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Characterization of Binding of Magnetic Nanoparticles to Rolling Circle Amplification Products by Turn-On Magnetic Assay
- 2019
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Ingår i: Biosensors-Basel. - : MDPI AG. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- The specific binding of oligonucleotide-tagged 100 nm magnetic nanoparticles (MNPs) to rolling circle products (RCPs) is investigated using our newly developed differential homogenous magnetic assay (DHMA). The DHMA measures ac magnetic susceptibility from a test and a control samples simultaneously and eliminates magnetic background signal. Therefore, the DHMA can reveal details of binding kinetics of magnetic nanoparticles at very low concentrations of RCPs. From the analysis of the imaginary part of the DHMA signal, we find that smaller MNPs in the particle ensemble bind first to the RCPs. When the RCP concentration increases, we observe the formation of agglomerates, which leads to lower number of MNPs per RCP at higher concentrations of RCPs. The results thus indicate that a full frequency range of ac susceptibility observation is necessary to detect low concentrations of target RCPs and a long amplification time is not required as it does not significantly increase the number of MNPs per RCP. The findings are critical for understanding the underlying microscopic binding process for improving the assay performance. They furthermore suggest DHMA is a powerful technique for dynamically characterizing the binding interactions between MNPs and biomolecules in fluid volumes.
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| 3. |
- Sepehri, Sobhan, 1986, et al.
(författare)
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Homogeneous Differential Magnetic Assay
- 2019
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Ingår i: Acs Sensors. - : American Chemical Society (ACS). - 2379-3694. ; 4:9, s. 2381-2388
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Tidskriftsartikel (refereegranskat)abstract
- Assays are widely used for detection of various targets, including pathogens, drugs, and toxins. Homogeneous assays are promising for the realization of point-of-care diagnostics as they do not require separation, immobilization, or washing steps. For low concentrations of target molecules, the speed and sensitivity of homogeneous assays have hitherto been limited by slow binding kinetics, time-consuming amplification steps, and the presence of a high background signal. Here, we present a homogeneous differential magnetic assay that utilizes a differential magnetic readout that eliminates previous limitations of homogeneous assays. The assay uses a gradiometer sensor configuration combined with precise microfluidic sample handling. This enables simultaneous differential measurement sample containing a synthesized Vibrio cholerae target and a negative control sample, which reduces the background signal and increases the readout speed. Very low concentrations of targets down to femtomolar levels are thus detectable without any additional amplification of the number of targets. Our homogeneous differential magnetic assay method opens new possibilities for rapid and highly sensitive diagnostics at the point of care.
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| 4. |
- Jansson, Roland, et al.
(författare)
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Future changes in the supply of goods and services from natural ecosystems : prospects for the European north
- 2015
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Ingår i: Ecology & Society. - : Resilience Alliance. - 1708-3087. ; 20:3
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Tidskriftsartikel (refereegranskat)abstract
- Humans depend on services provided by ecosystems, and how services are affected by climate change is increasingly studied. Few studies, however, address changes likely to affect services from seminatural ecosystems. We analyzed ecosystem goods and services in natural and seminatural systems, specifically how they are expected to change as a result of projected climate change during the 21st century. We selected terrestrial and freshwater systems in northernmost Europe, where climate is anticipated to change more than the global average, and identified likely changes in ecosystem services and their societal consequences. We did this by assembling experts from ecology, social science, and cultural geography in workshops, and we also performed a literature review. Results show that most ecosystem services are affected by multiple factors, often acting in opposite directions. Out of 14 services considered, 8 are expected to increase or remain relatively unchanged in supply, and 6 are expected to decrease. Although we do not predict collapse or disappearance of any of the investigated services, the effects of climate change in conjunction with potential economical and societal changes may exceed the adaptive capacity of societies. This may result in societal reorganization and changes in ways that ecosystems are used. Significant uncertainties and knowledge gaps in the forecast make specific conclusions about societal responses to safeguard human well-being questionable. Adapting to changes in ecosystem services will therefore require consideration of uncertainties and complexities in both social and ecological responses. The scenarios presented here provide a framework for future studies exploring such issues.
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| 5. |
- de Miranda, Noel F. C. C., et al.
(författare)
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DNA repair genes are selectively mutated in diffuse large B cell lymphomas
- 2013
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Ingår i: Journal of Experimental Medicine. - : Rockefeller University Press. - 0022-1007 .- 1540-9538. ; 210:9, s. 1729-1742
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Tidskriftsartikel (refereegranskat)abstract
- DNA repair mechanisms are fundamental for B cell development, which relies on the somatic diversification of the immunoglobulin genes by V(D)J recombination, somatic hypermutation, and class switch recombination. Their failure is postulated to promote genomic instability and malignant transformation in B cells. By performing targeted sequencing of 73 key DNA repair genes in 29 B cell lymphoma samples, somatic and germline mutations were identified in various DNA repair pathways, mainly in diffuse large B cell lymphomas (DLBCLs). Mutations in mismatch repair genes (EXO1, MSH2, and MSH6) were associated with microsatellite instability, increased number of somatic insertions/deletions, and altered mutation signatures in tumors. Somatic mutations in nonhomologous end-joining (NHEJ) genes (DCLRE1C/ARTEMIS, PRKDC/DNA-PKcs, XRCC5/KU80, and XRCC6/KU70) were identified in four DLBCL tumors and cytogenetic analyses revealed that translocations involving the immunoglobulin-heavy chain locus occurred exclusively in NHEJ-mutated samples. The novel mutation targets, CHEK2 and PARP1, were further screened in expanded DLBCL cohorts, and somatic as well as novel and rare germline mutations were identified in 8 and 5% of analyzed tumors, respectively. By correlating defects in a subset of DNA damage response and repair genes with genomic instability events in tumors, we propose that these genes play a role in DLBCL lymphomagenesis.
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| 6. |
- Jørgensen, Dolly, et al.
(författare)
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Policy Language in Restoration Ecology
- 2014
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Ingår i: Restoration Ecology. - : Wiley-Blackwell. - 1061-2971 .- 1526-100X. ; 22:1, s. 1-4
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Tidskriftsartikel (refereegranskat)abstract
- Relating restoration ecology to policy is one of the aims of the Society for Ecological Restoration and its journal Restoration Ecology. As an interdisciplinary team of researchers in both ecological science and political science, we have struggled with how policy-relevant language is and could be deployed in restoration ecology. Using language in scientific publications that resonates with overarching policy questions may facilitate linkages between researcher investigations and decision-makers' concerns on all levels. Climate change is the most important environmental problem of our time and to provide policymakers with new relevant knowledge on this problem is of outmost importance. To determine whether or not policy-specific language was being included in restoration ecology science, we surveyed the field of restoration ecology from 2008 to 2010, identifying 1,029 articles, which we further examined for the inclusion of climate change as a key element of the research. We found that of the 58 articles with climate change or global warming in the abstract, only 3 identified specific policies relevant to the research results. We believe that restoration ecologists are failing to include themselves in policy formation and implementation of issues such as climate change within journals focused on restoration ecology. We suggest that more explicit reference to policies and terminology recognizable to policymakers might enhance the impact of restoration ecology on decision-making processes.
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| 7. |
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| 8. |
- Sepehri, Sobhan, et al.
(författare)
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Study of magnetic beads-DNA coils binding kinetics using a differential homogeneous magnetic assay
- 2019
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Ingår i: Joint European Magnetic Symposia (JEMS) 2019. - Uppsala.
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Konferensbidrag (refereegranskat)abstract
- The binding kinetics of magnetic nanoparticles (MNPs) to rolling circle amplification products (RCPs) is investigated using a differential homogenous magnetic assay (DHMA)1. The DHMA utilizes a microfluidic device to measure the differential ac susceptibility signal between a reference and a test sample, taking advantage of the symmetry in a high-Tc SQUID gradiometer sensor2. The DHMA signal is related to the relative differences in the particle distribution of the two samples, and the background magnetic signal is thus eliminated. Therefore, minuscule changes in the nanoparticle’s concentration and size distribution of the test sample are directly detectable in the solution. This makes the DHMA a superior technique to characterize the binding interaction of the MNPs to biomolecules like RCPs specially at very low concentrations. The DHMA reveals that there is a competitive dynamic process between the MNP labelled RCPs and the unbound MNPs in the solution as a function of the RCP concentrations. The evidence of this dynamic in the signal fades as the MNP-RCP agglomerates are formed. The DHMA also shows that the smaller MNPs in the MNP size distribution take precedence over the larger MNP in immobilization on the RCPs. Comparing the DHMA responses with the turn-off detection method indicates that a full frequency range ac susceptibility observation is necessary when detecting low concentration of target RCPs. The findings are critical for understanding the underlying microscopic binding process and improving the assay performance. [1] Sepehri, S. et al, Differential homogeneous magnetic assay. Submitted. [2] Sepehri, S. et al. Volume-amplified magnetic bioassay integrated with microfluidic sample handling and high-Tc SQUID magnetic readout. APL Bioeng. 2, 016102 (2018).
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