| 1. |
- Murari, A., et al.
(author)
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A control oriented strategy of disruption prediction to avoid the configuration collapse of tokamak reactors
- 2024
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In: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
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Journal article (peer-reviewed)abstract
- The objective of thermonuclear fusion consists of producing electricity from the coalescence of light nuclei in high temperature plasmas. The most promising route to fusion envisages the confinement of such plasmas with magnetic fields, whose most studied configuration is the tokamak. Disruptions are catastrophic collapses affecting all tokamak devices and one of the main potential showstoppers on the route to a commercial reactor. In this work we report how, deploying innovative analysis methods on thousands of JET experiments covering the isotopic compositions from hydrogen to full tritium and including the major D-T campaign, the nature of the various forms of collapse is investigated in all phases of the discharges. An original approach to proximity detection has been developed, which allows determining both the probability of and the time interval remaining before an incoming disruption, with adaptive, from scratch, real time compatible techniques. The results indicate that physics based prediction and control tools can be developed, to deploy realistic strategies of disruption avoidance and prevention, meeting the requirements of the next generation of devices.
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| 2. |
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| 3. |
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| 4. |
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| 5. |
- Stroth, U., et al.
(author)
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Progress from ASDEX Upgrade experiments in preparing the physics basis of ITER operation and DEMO scenario development
- 2022
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In: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 62:4
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Journal article (peer-reviewed)abstract
- An overview of recent results obtained at the tokamak ASDEX Upgrade (AUG) is given. A work flow for predictive profile modelling of AUG discharges was established which is able to reproduce experimental H-mode plasma profiles based on engineering parameters only. In the plasma center, theoretical predictions on plasma current redistribution by a dynamo effect were confirmed experimentally. For core transport, the stabilizing effect of fast ion distributions on turbulent transport is shown to be important to explain the core isotope effect and improves the description of hollow low-Z impurity profiles. The L-H power threshold of hydrogen plasmas is not affected by small helium admixtures and it increases continuously from the deuterium to the hydrogen level when the hydrogen concentration is raised from 0 to 100%. One focus of recent campaigns was the search for a fusion relevant integrated plasma scenario without large edge localised modes (ELMs). Results from six different ELM-free confinement regimes are compared with respect to reactor relevance: ELM suppression by magnetic perturbation coils could be attributed to toroidally asymmetric turbulent fluctuations in the vicinity of the separatrix. Stable improved confinement mode plasma phases with a detached inner divertor were obtained using a feedback control of the plasma β. The enhanced D α H-mode regime was extended to higher heating power by feedback controlled radiative cooling with argon. The quasi-coherent exhaust regime was developed into an integrated scenario at high heating power and energy confinement, with a detached divertor and without large ELMs. Small ELMs close to the separatrix lead to peeling-ballooning stability and quasi continuous power exhaust. Helium beam density fluctuation measurements confirm that transport close to the separatrix is important to achieve the different ELM-free regimes. Based on separatrix plasma parameters and interchange-drift-Alfvén turbulence, an analytic model was derived that reproduces the experimentally found important operational boundaries of the density limit and between L- and H-mode confinement. Feedback control for the X-point radiator (XPR) position was established as an important element for divertor detachment control. Stable and detached ELM-free phases with H-mode confinement quality were obtained when the XPR was moved 10 cm above the X-point. Investigations of the plasma in the future flexible snow-flake divertor of AUG by means of first SOLPS-ITER simulations with drifts activated predict beneficial detachment properties and the activation of an additional strike point by the drifts.
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| 6. |
- Reimerdes, H., et al.
(author)
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Overview of the TCV tokamak experimental programme
- 2022
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In: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 62:4
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Journal article (peer-reviewed)abstract
- The tokamak a configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019-20 campaign its configurational flexibility has been enhanced with the installation of removable divertor gas baffles, its diagnostic capabilities with an extensive set of upgrades and its heating systems with new dual frequency gyrotrons. The gas baffles reduce coupling between the divertor and the main chamber and allow for detailed investigations on the role of fuelling in general and, together with upgraded boundary diagnostics, test divertor and edge models in particular. The increased heating capabilities broaden the operational regime to include T (e)/T (i) similar to 1 and have stimulated refocussing studies from L-mode to H-mode across a range of research topics. ITER baseline parameters were reached in type-I ELMy H-modes and alternative regimes with 'small' (or no) ELMs explored. Most prominently, negative triangularity was investigated in detail and confirmed as an attractive scenario with H-mode level core confinement but an L-mode edge. Emphasis was also placed on control, where an increased number of observers, actuators and control solutions became available and are now integrated into a generic control framework as will be needed in future devices. The quantity and quality of results of the 2019-20 TCV campaign are a testament to its successful integration within the European research effort alongside a vibrant domestic programme and international collaborations.
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| 7. |
- Thomas, H. J. D., et al.
(author)
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Global plant trait relationships extend to the climatic extremes of the tundra biome
- 2020
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In: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 11:1
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Journal article (peer-reviewed)abstract
- The majority of variation in six traits critical to the growth, survival and reproduction of plant species is thought to be organised along just two dimensions, corresponding to strategies of plant size and resource acquisition. However, it is unknown whether global plant trait relationships extend to climatic extremes, and if these interspecific relationships are confounded by trait variation within species. We test whether trait relationships extend to the cold extremes of life on Earth using the largest database of tundra plant traits yet compiled. We show that tundra plants demonstrate remarkably similar resource economic traits, but not size traits, compared to global distributions, and exhibit the same two dimensions of trait variation. Three quarters of trait variation occurs among species, mirroring global estimates of interspecific trait variation. Plant trait relationships are thus generalizable to the edge of global trait-space, informing prediction of plant community change in a warming world.
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| 8. |
- Maes, S.L., et al.
(author)
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Environmental drivers of increased ecosystem respiration in a warming tundra
- 2024
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In: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 629:8010, s. 105-113
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Journal article (peer-reviewed)abstract
- Arctic and alpine tundra ecosystems are large reservoirs of organic carbon. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain. This hampers the accuracy of global land carbon–climate feedback projections. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1 year up to 25 years. We show that a mean rise of 1.4 °C [confidence interval (CI) 0.9–2.0 °C] in air and 0.4 °C [CI 0.2–0.7 °C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22–38%] (n = 136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n = 9) and continued for at least 25 years (n = 136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.
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| 9. |
- Thomas, H. J.D., et al.
(author)
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Traditional plant functional groups explain variation in economic but not size-related traits across the tundra biome
- 2019
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In: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 28:2, s. 78-95
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Journal article (peer-reviewed)abstract
- © 2018 The Authors Global Ecology and Biogeography Published by John Wiley & Sons Ltd Aim: Plant functional groups are widely used in community ecology and earth system modelling to describe trait variation within and across plant communities. However, this approach rests on the assumption that functional groups explain a large proportion of trait variation among species. We test whether four commonly used plant functional groups represent variation in six ecologically important plant traits. Location: Tundra biome. Time period: Data collected between 1964 and 2016. Major taxa studied: 295 tundra vascular plant species. Methods: We compiled a database of six plant traits (plant height, leaf area, specific leaf area, leaf dry matter content, leaf nitrogen, seed mass) for tundra species. We examined the variation in species-level trait expression explained by four traditional functional groups (evergreen shrubs, deciduous shrubs, graminoids, forbs), and whether variation explained was dependent upon the traits included in analysis. We further compared the explanatory power and species composition of functional groups to alternative classifications generated using post hoc clustering of species-level traits. Results: Traditional functional groups explained significant differences in trait expression, particularly amongst traits associated with resource economics, which were consistent across sites and at the biome scale. However, functional groups explained 19% of overall trait variation and poorly represented differences in traits associated with plant size. Post hoc classification of species did not correspond well with traditional functional groups, and explained twice as much variation in species-level trait expression. Main conclusions: Traditional functional groups only coarsely represent variation in well-measured traits within tundra plant communities, and better explain resource economic traits than size-related traits. We recommend caution when using functional group approaches to predict tundra ecosystem change, or ecosystem functions relating to plant size, such as albedo or carbon storage. We argue that alternative classifications or direct use of specific plant traits could provide new insight into ecological prediction and modelling.
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| 10. |
- Soininen, E.M., et al.
(author)
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Location of studies and evidence of effects of herbivory on Arctic vegetation: a systematic map
- 2021
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In: Environmental Evidence. - : BioMed Central (BMC). - 2047-2382. ; 10:1
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Journal article (peer-reviewed)abstract
- Background: Herbivores modify the structure and function of tundra ecosystems. Understanding their impacts is necessary to assess the responses of these ecosystems to ongoing environmental changes. However, the effects of herbivores on plants and ecosystem structure and function vary across the Arctic. Strong spatial variation in herbivore effects implies that the results of individual studies on herbivory depend on local conditions, i.e., their ecological context. An important first step in assessing whether generalizable conclusions can be produced is to identify the existing studies and assess how well they cover the underlying environmental conditions across the Arctic. This systematic map aims to identify the ecological contexts in which herbivore impacts on vegetation have been studied in the Arctic. Specifically, the primary question of the systematic map was: “What evidence exists on the effects of herbivores on Arctic vegetation?”.Methods: We used a published systematic map protocol to identify studies addressing the effects of herbivores on Arctic vegetation. We conducted searches for relevant literature in online databases, search engines and specialist websites. Literature was screened to identify eligible studies, defined as reporting primary data on herbivore impacts on Arctic plants and plant communities. We extracted information on variables that describe the ecological context of the studies, from the studies themselves and from geospatial data. We synthesized the findings narratively and created a Shiny App where the coded data are searchable and variables can be visually explored.Review findings: We identified 309 relevant articles with 662 studies (representing different ecological contexts or datasets within the same article). These studies addressed vertebrate herbivory seven times more often than invertebrate herbivory. Geographically, the largest cluster of studies was in Northern Fennoscandia. Warmer and wetter parts of the Arctic had the largest representation, as did coastal areas and areas where the increase in temperature has been moderate. In contrast, studies spanned the full range of ecological context variables describing Arctic vertebrate herbivore diversity and human population density and impact.Conclusions: The current evidence base might not be sufficient to understand the effects of herbivores on Arctic vegetation throughout the region, as we identified clear biases in the distribution of herbivore studies in the Arctic and a limited evidence base on invertebrate herbivory. In particular, the overrepresentation of studies in areas with moderate increases in temperature prevents robust generalizations about the effects of herbivores under different climatic scenarios.
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| 11. |
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| 12. |
- Stock, M., et al.
(author)
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Harmonization of proton treatment planning for head and neck cancer using pencil beam scanning: first report of the IPACS collaboration group
- 2019
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In: Acta Oncologica. - : Informa UK Limited. - 0284-186X .- 1651-226X. ; 58:12, s. 1720-1730
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Journal article (peer-reviewed)abstract
- Background and purpose: A collaborative network between proton therapy (PT) centres in Trento in Italy, Poland, Austria, Czech Republic and Sweden (IPACS) was founded to implement trials and harmonize PT. This is the first report of IPACS with the aim to show the level of harmonization that can be achieved for proton therapy planning of head and neck (sino-nasal) cancer. Methods: CT-data sets of five patients were included. During several face-to-face and online meetings, a common treatment planning protocol was developed. Each centre used its own treatment planning system (TPS) and planning approach with some restrictions specified in the treatment planning protocol. In addition, volumetric modulated arc therapy (VMAT) photon plans were created. Results: For CTV1, the average D-median was 59.3 +/- 2.4 Gy(RBE) for protons and 58.8 +/- 2.0 Gy(RBE) for VMAT (aim was 56 Gy(RBE)). For CTV2, the average D-median was 71.2 +/- 1.0 Gy(RBE) for protons and 70.6 +/- 0.4 Gy(RBE) for VMAT (aim was 70 Gy(RBE)). The average D-2% for the spinal cord was 25.1 +/- 8.5 Gy(RBE) for protons and 47.6 +/- 1.4 Gy(RBE) for VMAT. The average D-2% for chiasm was 46.5 +/- 4.4 Gy(RBE) for protons and 50.8 +/- 1.4 Gy(RBE) for VMAT, respectively. Robust evaluation was performed and showed the least robust plans for plans with a low number of beams. Discussion: In conclusion, several influences on harmonization were identified: adherence/interpretation to/of the protocol, available technology, experience in treatment planning and use of different beam arrangements. In future, all OARs that should be included in the optimization need to be specified in order to further harmonize treatment planning.
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| 13. |
- Björkman, Anne, 1981, et al.
(author)
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Plant functional trait change across a warming tundra biome
- 2018
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 562:7725, s. 57-62
-
Journal article (peer-reviewed)abstract
- The tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem functioning. Here we explore the biome-wide relationships between temperature, moisture and seven key plant functional traits both across space and over three decades of warming at 117 tundra locations. Spatial temperature–trait relationships were generally strong but soil moisture had a marked influence on the strength and direction of these relationships, highlighting the potentially important influence of changes in water availability on future trait shifts in tundra plant communities. Community height increased with warming across all sites over the past three decades, but other traits lagged far behind predicted rates of change. Our findings highlight the challenge of using space-for-time substitution to predict the functional consequences of future warming and suggest that functions that are tied closely to plant height will experience the most rapid change. They also reveal the strength with which environmental factors shape biotic communities at the coldest extremes of the planet and will help to improve projections of functional changes in tundra ecosystems with climate warming.
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| 14. |
- Lembrechts, Jonas J., et al.
(author)
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SoilTemp : A global database of near-surface temperature
- 2020
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In: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26:11, s. 6616-6629
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Journal article (peer-reviewed)abstract
- Current analyses and predictions of spatially explicit patterns and processes in ecology most often rely on climate data interpolated from standardized weather stations. This interpolated climate data represents long-term average thermal conditions at coarse spatial resolutions only. Hence, many climate-forcing factors that operate at fine spatiotemporal resolutions are overlooked. This is particularly important in relation to effects of observation height (e.g. vegetation, snow and soil characteristics) and in habitats varying in their exposure to radiation, moisture and wind (e.g. topography, radiative forcing or cold-air pooling). Since organisms living close to the ground relate more strongly to these microclimatic conditions than to free-air temperatures, microclimatic ground and near-surface data are needed to provide realistic forecasts of the fate of such organisms under anthropogenic climate change, as well as of the functioning of the ecosystems they live in. To fill this critical gap, we highlight a call for temperature time series submissions to SoilTemp, a geospatial database initiative compiling soil and near-surface temperature data from all over the world. Currently, this database contains time series from 7,538 temperature sensors from 51 countries across all key biomes. The database will pave the way toward an improved global understanding of microclimate and bridge the gap between the available climate data and the climate at fine spatiotemporal resolutions relevant to most organisms and ecosystem processes.
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| 15. |
- Cavieres, Lohengrin A., et al.
(author)
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Facilitative plant interactions and climate simultaneously drive alpine plant diversity
- 2014
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In: Ecology Letters. - : Wiley. - 1461-0248 .- 1461-023X. ; 17:2, s. 193-202
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Journal article (peer-reviewed)abstract
- Interactions among species determine local-scale diversity, but local interactions are thought to have minor effects at larger scales. However, quantitative comparisons of the importance of biotic interactions relative to other drivers are rarely made at larger scales. Using a data set spanning 78 sites and five continents, we assessed the relative importance of biotic interactions and climate in determining plant diversity in alpine ecosystems dominated by nurse-plant cushion species. Climate variables related with water balance showed the highest correlation with richness at the global scale. Strikingly, although the effect of cushion species on diversity was lower than that of climate, its contribution was still substantial. In particular, cushion species enhanced species richness more in systems with inherently impoverished local diversity. Nurse species appear to act as a ‘safety net’ sustaining diversity under harsh conditions, demonstrating that climate and species interactions should be integrated when predicting future biodiversity effects of climate change.
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| 16. |
- Matena, M., et al.
(author)
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On-surface synthesis of a two-dimensional porous coordination network: Unraveling adsorbate interactions
- 2014
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In: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 90, s. 125408-125415
-
Journal article (peer-reviewed)abstract
- We present a detailed experimental and theoretical characterization of the adsorption of the perylene derivative 4,9-diaminoperylene-quinone-3,10-diimine (DPDI) on Cu(111) and compare it to its threefold dehydrogenated derivative 3deh-DPDI, which forms in a surface reaction upon annealing. While DPDI itself does not give rise to long-range ordered structures due to lack of appropriate functional groups, 3deh-DPDI acts as an exoligand in a Cu-coordinated honeycomb network on Cu(111). The main focus of this work lies on the analysis of intermolecular and molecule-substrate interactions by combining results from scanning tunneling microscopy, x-ray photoelectron spectroscopy, x-ray standing wave measurements, and density functional theory. We show, in particular, that the interactions between metal atoms and organic ligands effectively weaken the molecule-surface interactions for 3deh-DPDI leading to an increase in molecule-substrate distances compared to the DPDI precursor. Our experimental findings also shed light on the applicability of current theories, namely van der Waals corrections to density functional theory.
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| 17. |
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| 18. |
- You, S., et al.
(author)
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Vertical GaN devices : Process and reliability
- 2021
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In: Microelectronics and reliability. - : Elsevier Ltd. - 0026-2714 .- 1872-941X. ; 126
-
Journal article (peer-reviewed)abstract
- This paper reviews recent progress and key challenges in process and reliability for high-performance vertical GaN transistors and diodes, focusing on the 200 mm CMOS-compatible technology. We particularly demonstrated the potential of using 200 mm diameter CTE matched substrates for vertical power transistors, and gate module optimizations for device robustness. An alternative technology path based on coalescence epitaxy of GaN-on-Silicon is also introduced, which could enable thick drift layers of very low dislocation density. © 2021
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| 19. |
- Barrigón, E., et al.
(author)
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GaAs Nanowire pn-Junctions Produced by Low-Cost and High-Throughput Aerotaxy
- 2018
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In: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 18:2, s. 1088-1092
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Journal article (peer-reviewed)abstract
- Semiconductor nanowires could significantly boost the functionality and performance of future electronics, light-emitting diodes, and solar cells. However, realizing this potential requires growth methods that enable high-throughput and low-cost production of nanowires with controlled doping. Aerotaxy is an aerosol-based method with extremely high growth rate that does not require a growth substrate, allowing mass-production of high-quality nanowires at a low cost. So far, pn-junctions, a crucial element of solar cells and light-emitting diodes, have not been realized by Aerotaxy growth. Here we report a further development of the Aerotaxy method and demonstrate the growth of GaAs nanowire pn-junctions. Our Aerotaxy system uses an aerosol generator for producing the catalytic seed particles, together with a growth reactor with multiple consecutive chambers for growth of material with different dopants. We show that the produced nanowire pn-junctions have excellent diode characteristics with a rectification ratio of >105, an ideality factor around 2, and very promising photoresponse. Using electron beam induced current and hyperspectral cathodoluminescence, we determined the location of the pn-junction and show that the grown nanowires have high doping levels, as well as electrical properties and diffusion lengths comparable to nanowires grown using metal organic vapor phase epitaxy. Our findings demonstrate that high-quality GaAs nanowire pn-junctions can be produced using a low-cost technique suitable for mass-production, paving the way for industrial-scale production of nanowire-based solar cells.
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| 20. |
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| 21. |
- Krause-Jensen, D, et al.
(author)
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Nordic Blue Carbon Ecosystems: Status and Outlook
- 2022
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In: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 9
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Research review (peer-reviewed)abstract
- Vegetated coastal and marine habitats in the Nordic region include salt marshes, eelgrass meadows and, in particular, brown macroalgae (kelp forests and rockweed beds). Such habitats contribute to storage of organic carbon (Blue Carbon – BC) and support coastal protection, biodiversity and water quality. Protection and restoration of these habitats therefore have the potential to deliver climate change mitigation and co-benefits. Here we present the existing knowledge on Nordic BC habitats in terms of habitat area, C-stocks and sequestration rates, co-benefits, policies and management status to inspire a coherent Nordic BC roadmap. The area extent of BC habitats in the region is incompletely assessed, but available information sums up to 1,440 km2 salt marshes, 1,861 (potentially 2,735) km2 seagrass meadows, and 16,532 km2 (potentially 130,735 km2, including coarse Greenland estimates) brown macroalgae, yielding a total of 19,833 (potentially 134,910) km2. Saltmarshes and seagrass meadows have experienced major declines over the past century, while macroalgal trends are more diverse. Based on limited salt marsh data, sediment C-stocks average 3,311 g Corg m-2 (top 40-100 cm) and sequestration rates average 142 g Corg m-2 yr-1. Eelgrass C-stocks average 2,414 g Corg m-2 (top 25 cm) and initial data for sequestration rates range 5-33 g Corg m-2, quantified for one Greenland site and one short term restoration. For Nordic brown macroalgae, peer-reviewed estimates of sediment C-stock and sequestration are lacking. Overall, the review reveals substantial Nordic BC-stocks, but highlights that evidence is still insufficient to provide a robust estimate of all Nordic BC-stocks and sequestration rates. Needed are better quantification of habitat area, C-stocks and fluxes, particularly for macroalgae, as well as identification of target areas for BC management. The review also points to directives and regulations protecting Nordic marine vegetation, and local restoration initiatives with potential to increase C-sequestration but underlines that increased coordination at national and Nordic scales and across sectors is needed. We propose a Nordic BC roadmap for science and management to maximize the potential of BC habitats to mitigate climate change and support coastal protection, biodiversity and additional ecosystem functions.
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| 22. |
- Olén, Ola, et al.
(author)
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Increasing Risk of Lymphoma Over Time in Crohn's Disease but Not in Ulcerative Colitis : A Scandinavian Cohort Study
- 2023
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In: Clinical Gastroenterology and Hepatology. - : Elsevier. - 1542-3565 .- 1542-7714. ; 21:12, s. 3132-3142
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Journal article (peer-reviewed)abstract
- Background & Aims: Earlier studies have provided varying risk estimates for lymphoma in patients with inflammatory bowel disease (IBD), but often have been limited by detection biases (especially during the first year of follow-up evaluation), misclassification, and small sample size; and rarely reflect modern-day management of IBD.Methods: We performed a binational register-based cohort study (Sweden and Denmark) from 1969 to 2019. We compared 164,716 patients with IBD with 1,639,027 matched general population reference individuals. Cox regression estimated hazard ratios (HRs) for incident lymphoma by lymphoma subtype, excluding the first year of follow-up evaluation.Results: From 1969 to 2019, 258 patients with Crohn's disease (CD), 479 patients with ulcerative colitis (UC), and 6675 matched reference individuals developed lymphoma. This corresponded to incidence rates of 35 (CD) and 34 (UC) per 100,000 person-years in IBD patients, compared with 28 and 33 per 100,000 person-years in their matched reference individuals. Although both CD (HR, 1.32; 95% CI, 1.16–1.50) and UC (HR, 1.09; 95% CI, 1.00–1.20) were associated with an increase in lymphoma, the 10-year cumulative incidence difference was low even in CD patients (0.08%; 95% CI, 0.02–0.13). HRs have increased in the past 2 decades, corresponding to increasing use of immunomodulators and biologics during the same time period. HRs were increased for aggressive B-cell non-Hodgkin lymphoma in CD and UC patients, and for T-cell non-Hodgkin lymphoma in CD patients. Although the highest HRs were observed in patients exposed to combination therapy (immunomodulators and biologics) or second-line biologics, we also found increased HRs in patients naïve to such drugs.Conclusions: During the past 20 years, the risk of lymphomas have increased in CD, but not in UC, and were driven mainly by T-cell lymphomas and aggressive B-cell lymphomas.
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| 23. |
- Prevéy, Janet S., et al.
(author)
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The tundra phenology database: more than two decades of tundra phenology responses to climate change
- 2022
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In: Arctic Science. - : Canadian Science Publishing. - 2368-7460. ; 8:3, s. 1026-1039
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Journal article (peer-reviewed)abstract
- Observations of changes in phenology have provided some of the strongest signals of the effects of climate change on terrestrial ecosystems. The International Tundra Experiment (ITEX), initiated in the early 1990s, established a common protocol to measure plant phenology in tundra study areas across the globe. Today, this valuable collec-tion of phenology measurements depicts the responses of plants at the colder extremes of our planet to experimental and ambient changes in temperature over the past decades. The database contains 150 434 phenology observations of 278 plant species taken at 28 study areas for periods of 1–26 years. Here we describe the full data set to increase the visibility and use of these data in global analyses and to invite phenology data contributions from underrepresented tundra locations. Portions of this tundra phenology database have been used in three recent syntheses, some data sets are expanded, others are from entirely new study areas, and the entirety of these data are now available at the Polar Data Catalogue (https://doi.org/10.21963/13215).
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| 24. |
- Brunner, I., et al.
(author)
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Fine-root turnover rates of European forests revisited: an analysis of data from sequential coring and ingrowth cores
- 2013
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In: Plant and Soil. - : Springer Netherlands. - 0032-079X .- 1573-5036. ; 362:1-2, s. 357-372
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Journal article (peer-reviewed)abstract
- Background and Aims Forest trees directly contribute to carbon cycling in forest soils through the turnover of their fine roots. In this study we aimed to calculate root turnover rates of common European forest tree species and to compare them with most frequently published values. Methods We compiled available European data and applied various turnover rate calculation methods to the resulting database. We used Decision Matrix and Maximum-Minimum formula as suggested in the literature. Results Mean turnover rates obtained by the combination of sequential coring and Decision Matrix were 0.86 yr−1 for Fagus sylvatica and 0.88 yr−1 for Picea abies when maximum biomass data were used for the calculation, and 1.11 yr−1 for both species when mean biomass data were used. Using mean biomass rather than maximum resulted in about 30 % higher values of root turnover. Using the Decision Matrix to calculate turnover rate doubled the rates when compared to the Maximum-Minimum formula. The Decision Matrix, however, makes use of more input information than the Maximum-Minimum formula. Conclusions We propose that calculations using the Decision Matrix with mean biomass give the most reliable estimates of root turnover rates in European forests and should preferentially be used in models and C reporting.
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| 25. |
- Christensson, A, et al.
(author)
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Serum prostate specific antigen complexed to alpha 1-antichymotrypsin as an indicator of prostate cancer
- 1993
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In: Journal of Urology. - 1527-3792. ; 150:1, s. 100-105
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Journal article (peer-reviewed)abstract
- Prostate specific antigen (PSA) in serum has recently been shown to occur in complex with alpha 1-antichymotrypsin and as an approximately 30 kDa. noncomplexed molecular form. We characterized PSA by 3 different assays in samples from 144 patients with benign prostatic hyperplasia (BPH) and 121 with carcinoma of the prostate. One of these noncompetitive assays measured total PSA by detecting PSA complexed to serine proteinase inhibitors and the noncomplexed molecular form, a second measured only PSA in complex with alpha 1-antichymotrypsin, whereas a third detected the noncomplexed form. PSA in complex with alpha 1-antichymotrypsin was the predominant form in all patient sera. Noncomplexed PSA constituted a minor fraction that was significantly smaller in patients with untreated prostate cancer than in those with BPH (p < 0.0001). The proportion of noncomplexed PSA does not correlate to the serum concentration of PSA or that of alpha 1-antichymotrypsin. In men with a serum PSA concentration of less than 10 micrograms./l. the combination of assays measuring total PSA immunoreactivity, the noncomplexed molecular form and PSA in complex with alpha 1-antichymotrypsin may facilitate discrimination between prostate cancer and BPH.
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| 26. |
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| 27. |
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| 28. |
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| 29. |
- Kainu, T, et al.
(author)
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Somatic deletions in hereditary breast cancers implicate 13q21 as a putative novel breast cancer susceptibility locus
- 2000
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In: Proceedings of the National Academy of Sciences. - 1091-6490. ; 97:17, s. 9603-9608
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Journal article (peer-reviewed)abstract
- A significant proportion of familial breast cancers cannot be explained by mutations in the BRCA1 or BRCA2 genes. We applied a strategy to identify predisposition loci for breast cancer by using mathematical models to identify early somatic genetic deletions in tumor tissues followed by targeted linkage analysis. Comparative genomic hybridization was used to study 61 breast tumors from 37 breast cancer families with no identified BRCA1 or BRCA2 mutations. Branching and phylogenetic tree models predicted that loss of 13q was one of the earliest genetic events in hereditary cancers. In a Swedish family with five breast cancer cases, all analyzed tumors showed distinct 13q deletions, with the minimal region of loss at 13q21-q22. Genotyping revealed segregation of a shared 13q21 germ-line haplotype in the family. Targeted linkage analysis was carried out in a set of 77 Finnish, Icelandic, and Swedish breast cancer families with no detected BRCA1 and BRCA2 mutations. A maximum parametric two-point logarithm of odds score of 2.76 was obtained for a marker at 13q21 (D13S1308, theta = 0.10). The multipoint logarithm of odds score under heterogeneity was 3.46. The results were further evaluated by simulation to assess the probability of obtaining significant evidence in favor of linkage by chance as well as to take into account the possible influence of the BRCA2 locus, located at a recombination fraction of 0.25 from the new locus. The simulation substantiated the evidence of linkage at D13S1308 (P < 0.0017). The results warrant studies of this putative breast cancer predisposition locus in other populations.
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| 30. |
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| 31. |
- Ohlsson, B. J., et al.
(author)
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Size-, shape-, and position-controlled GaAs nano-whiskers
- 2001
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 79:20, s. 3335-3337
-
Journal article (peer-reviewed)abstract
- We have developed a technique for the synthesis of size-selected, GaAs, epitaxial nano-whiskers, grown on a crystalline substrate. As catalysts, we used size-selected gold aerosol particles, which enabled us to fully vary the surface coverage independently of the whisker diameter. The whiskers were rod shaped, with a uniform diameter between 10 and 50 nm, correlated to the size of the catalytic seed. Furthermore, by the use of nano-manipulation of the aerosol particles by means of atomic force microscopy, we can nucleate individual nano-whiskers in a controlled manner at specific positions on a substrate with accuracy on the nm level.
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| 32. |
- Tsegaye, T., et al.
(author)
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Complementarity and quantum erasure with entangled-photon states
- 2000
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In: Physical Review A. Atomic, Molecular, and Optical Physics. - 1050-2947 .- 1094-1622. ; 62:3, s. art. no.-32106
-
Journal article (peer-reviewed)abstract
- A quantum-erasure experiment was performed on superposition states of two photons in either of two spatiotemporal modes. Symmetrical tapping of energy from the two-mode state creates a four-mode entangled state. A direct measurement of one photon in two of the modes reveals the path of the second one, thereby eliminating the possibility of observing interference between the two remaining modes. It is shown that a unitary rotation of one of the two-mode states erases the path information; as a consequence, the visibility of the other two-mode state can be resurrected.
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| 33. |
- Tsegaye, T., et al.
(author)
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Experimental demonstration of three mutually orthogonal polarization states of entangled photons
- 2000
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 85:24, s. 5013-5017
-
Journal article (peer-reviewed)abstract
- Linearly polarized classical light can be expressed in a vertical and a horizontal component. Geometrically rotating vertically polarized light by 90 degrees will convert it to the orthogonal horizontal polarization. We have experimentally generated a two-photon state of light which evolves into an orthogonal state upon geometrical rotation by 60 degrees. Rotating this state by an additional 60 degrees will yield a state which is mutually orthogonal to the first two states. Generalizing this procedure, one can generate N + 1 mutually orthogonal N-photon states that cyclicly evolve from one to another upon a geometric rotation by 180/(N + 1) degrees.
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| 34. |
- Vickers, Andrew J., et al.
(author)
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Prostate specific antigen concentration at age 60 and death or metastasis from prostate cancer : Case-control study
- 2010
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In: BMJ (Online). - : BMJ. - 1756-1833 .- 0959-8138 .- 1468-5833. ; 341:7773
-
Journal article (peer-reviewed)abstract
- Objective: To determine the relation between concentrations of prostate specific antigen at age 60 and subsequent diagnosis of clinically relevant prostate cancer in an unscreened population to evaluate whether screening for prostate cancer and chemoprevention could be stratified by risk. Design: Case-control study with 1:3 matching nested within a highly representative population based cohort study. Setting: General population of Sweden taking part in the Malmo Preventive Project. Cancer registry at the National Board of Health and Welfare. Participants: 1167 men aged 60 who provided blood samples in 1981 and were followed up to age 85. Main outcome measures: Metastasis or death from prostate cancer. Results: The rate of screening during the course of the study was low. There were 43 cases of metastasis and 35 deaths from prostate cancer. Concentration of prostate specific antigen at age 60 was associated with prostate cancer metastasis (area under the curve 0.86, 95% confidence interval 0.79 to 0.92; P<0.001) and death from prostate cancer (0.90, 0.84 to 0.96; P<0.001). The greater the number for the area under the curve (values from 0 to 1) the better the test. Although only a minority of the men with concentrations in the top quarter (>2 ng/ml) develop fatal prostate cancer, 90% (78% to 100%) of deaths from prostate cancer occurred in these men. Conversely, men aged 60 with concentrations at the median or lower (≤1 ng/ml) were unlikely to have clinically relevant prostate cancer (0.5% risk of metastasis by age 85 and 0.2% risk of death from prostate cancer). Conclusions: The concentration of prostate specific antigen at age 60 predicts lifetime risk of metastasis and death from prostate cancer. Though men aged 60 with concentrations below the median (≤1 ng/ml) might harbour prostate cancer, it is unlikely to become life threatening. Such men could be exempted from further screening, which should instead focus on men with higher concentrations.
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| 35. |
- Barnes, W. L., et al.
(author)
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Solid-state single photon sources : light collection strategies
- 2002
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In: European Physical Journal D. - : Springer Science and Business Media LLC. - 1434-6060 .- 1434-6079. ; 18:2, s. 197-210
-
Journal article (peer-reviewed)abstract
- We examine the problem of efficiently collecting the photons produced by solid-state single photon sources. The extent of the problem is first established with the aid of simple physical concepts. Several approaches to improving the collection efficiency are then examined and are broadly categorized into two types. First are those based on cavity quantum dynamics, in which the pathways by which the source may emit a photon are restricted, thus channeling emission into one desired mode. Second are those where we try to reshape the free space modes into a target mode in an optimal way, by means of refraction, without fundamentally altering the way in which the source emits. Respectively, we examine a variety of microcavities and solid immersion lenses. Whilst we find that the micropillar microcavities offer the highest collection efficiency (similar to70%), choosing this approach may not always be appropriate due to other constraints. Details of the different approaches, their merits and drawbacks are discussed in detail.
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| 36. |
- Björk, Anders, et al.
(author)
-
Making an ultralow platinum content bimetallic catalyst on carbon fibres for electro-oxidation of ammonia in wastewater
- 2019
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In: Sustainable Energy & Fuels. - 2398-4902.
-
Journal article (peer-reviewed)abstract
- Electrocatalysis of wastewater containing ammonia is a promising alternative to chemical and biological water purification for several reasons, one being that energy-rich hydrogen gas is generated as a by-product while the reaction can be strictly controlled to meet demands. An objective has been to reduce the loading of expensive platinum (Pt) in the catalyst electrodes, and to reduce the poisoning of the metal surface during the electrolysis. Herein, the co-deposition of a copper–platinum (Cu–Pt) bimetallic alloy onto carbon filaments, stripped from their polymeric coating, is shown to give an electrocatalytic performance superior to that of pure Pt at a content of less than 3 wt% Pt. The key to the enhanced performance was to take advantage of micrometer-sized carbon filaments to distribute a very large bimetallic alloy surface uniformly over the filaments. The Cu–Pt-alloy-coated filaments also suffer less electrode poisoning than pure Pt, and are bonded more strongly to the carbon fibre due to better mechanical interlocking between the bimetallic alloy and the carbon filaments. High-resolution electron microscopy studies combined with a tuned electro-deposition process made it possible to tailor the catalyst micro/nano morphology to reach a uniform coverage, surrounding the entire carbon filaments. The results are promising steps towards large-scale wastewater treatment, combined with clean energy production from regenerated hydrogen.
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| 37. |
- Björk, Göran, 1956, et al.
(author)
-
Flow of Canadian Basin Deep Water in the Western Eurasian Basin of the Arctic Ocean
- 2010
-
In: Deep Sea Research. - : Elsevier BV. - 0967-0637 .- 1879-0119. ; 57:4, s. 577-586
-
Journal article (peer-reviewed)abstract
- The LOMROG 2007 expedition targeted the previously unexplored southern part of the Lomonosov Ridge north of Greenland together with a section from the Morris Jesup Rise to Gakkel Ridge. The oceanographic data shows that Canadian Basin Deep Water (CBDW) passes the Lomonosov Ridge in the area of the Intra Basin close to the North Pole and then continues along the ridge towards Greenland and further along its northernmost continental slope. The CBDW is clearly evident as a salinity maximum and oxygen minimum at a depth of about 2000 m. The cross slope sections at the Amundsen Basin side of the Lomonosov Ridge and further south at the Morris Jesup Rise show a sharp frontal structure higher up in the water column between Makarov Basin water and Amundsen Basin water. The frontal structure continues upward into the Atlantic Water up to a depth of about 300 m. The observed water mass division at levels well above the ridge crest indicates a strong topographic steering of the flow and that different water masses tend to pass the ridge guided by ridge-crossing isobaths at local topographic heights and depressions. A rough scaling analysis shows that the extremely steep and sharply turning bathymetry of the Morris Jesup Rise may force the boundary current to separate and generate deep eddies.
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| 38. |
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| 39. |
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| 40. |
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| 41. |
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| 42. |
- Elphinstone, Cassandra, et al.
(author)
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Multiple Pleistocene refugia for Arctic Bell-Heather revealed with genomic analyses of modern and historic plants
- 2024
-
In: Journal of Biogeography. - 0305-0270 .- 1365-2699.
-
Journal article (peer-reviewed)abstract
- Aim: Arctic plants survived the Pleistocene glaciations in unglaciated refugia. The number, ages, and locations of these refugia are often unclear. We use high-resolution genomic data from present-day and Little-Ice-Age populations of Arctic Bell-Heather to re-evaluate the biogeography of this species and determine whether it had multiple independent refugia or a single refugium in Beringia. Location: Circumpolar Arctic and Coastal British Columbia (BC) alpine. Taxon: Cassiope tetragona L., subspecies saximontana and tetragona, outgroup C. mertensiana (Ericaceae). Methods: We built genotyping-by-sequencing (GBS) libraries using Cassiope tetragona tissue from 36 Arctic locations, including two ~250- to 500-year-old populations collected under glacial ice on Ellesmere Island, Canada. We assembled a de novo GBS reference to call variants. Population structure, genetic diversity and demography were inferred from PCA, ADMIXTURE, fastsimcoal2, SplitsTree, and several population genomics statistics. Results: Population structure analyses identified 4–5 clusters that align with geographic locations. Nucleotide diversity was highest in Beringia and decreased eastwards across Canada. Demographic coalescent analyses dated the following splits with Alaska: BC subspecies saximontana (5 mya), Russia (~1.4 mya), Europe (>200–600 kya), and Greenland (~60 kya). Northern Canada populations appear to have formed during the current interglacial (7–9 kya). Admixture analyses show genetic variants from Alaska appear more frequently in present-day than historic plants on Ellesmere Island. Conclusions: Population and demographic analyses support BC, Alaska, Russia, Europe and Greenland as all having had independent Pleistocene refugia. Northern Canadian populations appear to be founded during the current interglacial with genetic contributions from Alaska, Europe and Greenland. We found evidence, on Ellesmere Island, for continued recent gene flow in the last 250–500 years. These results suggest that a re-analysis of other Arctic species with shallow population structure using higher resolution genomic markers and demographic analyses may help reveal deeper structure and other circumpolar glacial refugia.
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| 43. |
- George, Rushingisha, et al.
(author)
-
Methane emission and sulfide levels increase in tropical seagrass sediments during temperature stress: A mesocosm experiment
- 2020
-
In: Ecology and Evolution. - : Wiley. - 2045-7758. ; 10:4, s. 1917-1928
-
Journal article (peer-reviewed)abstract
- Climate change-induced ocean warming is expected to greatly affect carbon dynamics and sequestration in vegetated shallow waters, especially in the upper subtidal where water temperatures may fluctuate considerably and can reach high levels at low tides. This might alter the greenhouse gas balance and significantly reduce the carbon sink potential of tropical seagrass meadows. In order to assess such consequences, we simulated temperature stress during low tide exposures by subjecting seagrass plants (Thalassia hemprichii) and associated sediments to elevated midday temperature spikes (31, 35, 37, 40, and 45°C) for seven consecutive days in an outdoor mesocosm setup. During the experiment, methane release from the sediment surface was estimated using gas chromatography. Sulfide concentration in the sediment pore water was determined spectrophotometrically, and the plant's photosynthetic capacity as electron transport rate (ETR), and maximum quantum yield (Fv/Fm) was assessed using pulse amplitude modulated (PAM) fluorometry. The highest temperature treatments (40 and 45°C) had a clear positive effect on methane emission and the level of sulfide in the sediment and, at the same time, clear negative effects on the photosynthetic performance of seagrass plants. The effects observed by temperature stress were immediate (within hours) and seen in all response variables, including ETR, Fv/Fm, methane emission, and sulfide levels. In addition, both the methane emission and the size of the sulfide pool were already negatively correlated with changes in the photosynthetic rate (ETR) during the first day, and with time, the correlations became stronger. These findings show that increased temperature will reduce primary productivity and increase methane and sulfide levels. Future increases in the frequency and severity of extreme temperature events could hence reduce the climate mitigation capacity of tropical seagrass meadows by reducing CO2 sequestration, increase damage from sulfide toxicity, and induce the release of larger amounts of methane. © 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
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| 44. |
- Grossmann, Lukas, et al.
(author)
-
On-surface photopolymerization of two-dimensional polymers ordered on the mesoscale
- 2021
-
In: Nature Chemistry. - : Springer Nature. - 1755-4330 .- 1755-4349. ; 13:8, s. 730-736
-
Journal article (peer-reviewed)abstract
- The use of solid supports and ultra-high vacuum conditions for the synthesis of two-dimensional polymers is attractive, as it can enable thorough characterization, often with submolecular resolution, and prevent contamination. However, most on-surface polymerizations are thermally activated, which often leads to high defect densities and relatively small domain sizes. Here, we have obtained a porous two-dimensional polymer that is ordered on the mesoscale by the two-staged topochemical photopolymerization of fluorinated anthracene triptycene (fantrip) monomers on alkane-passivated graphite surfaces under ultra-high vacuum. First, the fantrip monomers self-assemble into highly ordered monolayer structures, where all anthracene moieties adopt a suitable arrangement for photopolymerization. Irradiation with violet light then induces complete covalent cross-linking by [4+4] photocycloaddition to form a two-dimensional polymer, while fully preserving the long-range order of the self-assembled structure. The extent of the polymerization is confirmed by local infrared spectroscopy and scanning tunnelling microscopy characterization, in agreement with density functional theory calculations, which also gives mechanistic insights.
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| 45. |
- Grossmann, Lukas, et al.
(author)
-
Steering Self-Assembly of Three-Dimensional Iptycenes on Au(111) by Tuning Molecule-Surface Interactions
- 2022
-
In: Angewandte Chemie International Edition. - : Wiley-V C H Verlag GMBH. - 1433-7851 .- 1521-3773. ; 61:25
-
Journal article (peer-reviewed)abstract
- Self-assembly of three-dimensional molecules is scarcely studied on surfaces. Their modes of adsorption can exhibit far greater variability compared to (nearly) planar molecules that adsorb mostly flat on surfaces. This additional degree of freedom can have decisive consequences for the expression of intermolecular binding motifs, hence the formation of supramolecular structures. The determining molecule-surface interactions can be widely tuned, thereby providing a new powerful lever for crystal engineering in two dimensions. Here, we study the self-assembly of triptycene derivatives with anthracene blades on Au(111) by Scanning Tunneling Microscopy, Near Edge X-ray Absorption Fine Structure and Density Functional Theory. The impact of molecule-surface interactions was experimentally tested by comparing pristine with iodine-passivated Au(111) surfaces. Thereby, we observed a fundamental change of the adsorption mode that triggered self-assembly of an entirely different structure.
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| 46. |
- Insulander Björk, Klara L, 1982, et al.
(author)
-
Commercial thorium fuel manufacture and irradiation: Testing (Th,Pu)O-2 and (Th,U)O-2 in the "Seven-Thirty" program
- 2015
-
In: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 75, s. 79-86
-
Journal article (peer-reviewed)abstract
- Thorium based fuels are being tested in the Halden Research Reactor in Norway with the aim of producing the data necessary for licensing of these fuels in today's light water reactors. The fuel types currently under irradiation are thorium oxide fuel with plutonium as the fissile component, and uranium fuel with thorium as an additive for enhancement of thermo-mechanical and neutronic fuel properties. Fuel temperatures, rod pressures and dimensional changes are monitored on-line for quantification of thermo-mechanical behavior and fission gas release. Preliminary irradiation results show benefits in terms of lower fuel temperatures, mainly caused by improved thermal conductivity of the thorium fuels. In parallel with the irradiation, a manufacturing procedure for thorium-plutonium mixed oxide fuel is developed with the aim to manufacture industrially relevant high-quality fuel pellets for the next phase of the irradiation campaign.
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| 47. |
- Jakobsson, Martin, et al.
(author)
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Evidence for an ice shelf covering the central Arctic Ocean during the penultimate glaciation
- 2016
-
In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
-
Journal article (peer-reviewed)abstract
- The hypothesis of a km-thick ice shelf covering the entire Arctic Ocean during peak glacial conditions was proposed nearly half a century ago. Floating ice shelves preserve few direct traces after their disappearance, making reconstructions difficult. Seafloor imprints of ice shelves should, however, exist where ice grounded along their flow paths. Here we present new evidence of ice-shelf groundings on bathymetric highs in the central Arctic Ocean, resurrecting the concept of an ice shelf extending over the entire central Arctic Ocean during at least one previous ice age. New and previously mapped glacial landforms together reveal flow of a spatially coherent, in some regions41-km thick, central Arctic Ocean ice shelf dated to marine isotope stage 6 (similar to 140 ka). Bathymetric highs were likely critical in the ice-shelf development by acting as pinning points where stabilizing ice rises formed, thereby providing sufficient back stress to allow ice shelf thickening.
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| 48. |
- Lilja, Hans, et al.
(author)
-
Significance and metabolism of complexed and noncomplexed prostate specific antigen forms, and human glandular kallikrein 2 in clinically localized prostate cancer before and after radical prostatectomy
- 1999
-
In: Journal of Urology. - 1527-3792. ; 162:6, s. 2029-2035
-
Journal article (peer-reviewed)abstract
- PURPOSE: We studied plasma concentrations and elimination rates of prostate specific antigen (PSA) complexed to alpha1-antichymotrypsin and alpha2-macroglobulin, free PSA, total PSA (free PSA plus PSA alpha1-antichymotrypsin) and human glandular kallikrein 2 before, during and after radical retropubic prostatectomy for clinically localized prostate cancer. MATERIALS AND METHODS: Plasma was collected and frozen within 10 minutes after sampling from 18 patients undergoing radical retropubic prostatectomy for prostate cancer. One sample was drawn preoperatively. Subsequent sampling intervals were 5 to 20 minutes perioperatively, 2 to 4 hours during the first 12 postoperative hours and 24 to 48 hours until postoperative day 14. Free PSA, PSA alpha1-antichymotrypsin, total PSA, PSA alpha2-macroglobulin and human glandular kallikrein 2 were measured with time resolved immunofluorometric assays. RESULTS: Preoperatively PSA alpha2-macroglobulin was undetectable (less than 2 ng./ml.) in 17 of 18 patients. Human glandular kallikrein 2, free PSA and total PSA but not PSA alpha1-antichymotrypsin were significantly higher in patients with extraprostatic cancer (pT3a-pT4a, pN1) compared to those with organ confined cancer (pT2a/b). Surgical manipulation of the prostate caused no detectable elevation of human glandular kallikrein 2, PSA alpha1-antichymotrypsin or PSA alpha2-macroglobulin. In contrast, a mean 9.6-fold increase (range 3.4 to 22) in free PSA was noted 5 minutes after prostatectomy. Free PSA was eliminated from plasma in a biphasic exponential pattern with an early plasma half-life of 55 minutes and a late plasma half-life of 18 hours. PSA alpha1-antichymotrypsin decreased slowly, whereas human glandular kallikrein 2 was detectable only 12 hours after prostatectomy. PSA alpha2-macroglobulin remained at insignificant, nondetectable concentrations during the entire perioperative and postoperative period. CONCLUSIONS: Release of free PSA contributes to the elevation of plasma total PSA after prostatectomy. Free PSA is enzymatically inactive as the release does not result in subsequent elevation of PSA alpha1-antichymotrypsin or PSA alpha2-macroglobulin. Biphasic exponential elimination of free PSA may be explained by rapid extracellular redistribution (early half-life) and glomerular filtration in the kidneys (late half-life). Our data suggest rapid metabolism of human glandular kallikrein 2 but do not support suggestions of the significance in vivo of complex formations with alpha2-macroglobulin as a major means to eliminate PSA from plasma in patients with clinically localized prostate cancer.
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| 49. |
- Metcalfe, Daniel B., et al.
(author)
-
Patchy field sampling biases understanding of climate change impacts across the Arctic
- 2018
-
In: Nature Ecology and Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 2:9, s. 1443-1448
-
Journal article (peer-reviewed)abstract
- Effective societal responses to rapid climate change in the Arctic rely on an accurate representation of region-specific ecosystem properties and processes. However, this is limited by the scarcity and patchy distribution of field measurements. Here, we use a comprehensive, geo-referenced database of primary field measurements in 1,840 published studies across the Arctic to identify statistically significant spatial biases in field sampling and study citation across this globally important region. We find that 31% of all study citations are derived from sites located within 50 km of just two research sites: Toolik Lake in the USA and Abisko in Sweden. Furthermore, relatively colder, more rapidly warming and sparsely vegetated sites are under-sampled and under-recognized in terms of citations, particularly among microbiology-related studies. The poorly sampled and cited areas, mainly in the Canadian high-Arctic archipelago and the Arctic coastline of Russia, constitute a large fraction of the Arctic ice-free land area. Our results suggest that the current pattern of sampling and citation may bias the scientific consensuses that underpin attempts to accurately predict and effectively mitigate climate change in the region. Further work is required to increase both the quality and quantity of sampling, and incorporate existing literature from poorly cited areas to generate a more representative picture of Arctic climate change and its environmental impacts.
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| 50. |
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