| 1. |
- Conley, Daniel, et al.
(författare)
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Hypoxia-Related Processes in the Baltic Sea
- 2009
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:10, s. 3412-3420
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Tidskriftsartikel (refereegranskat)abstract
- Hypoxia, a growing worldwide problem, has been intermittently present in the modern Baltic Sea since its formation ca. 8000 cal. yr BP. However, both the spatial extent and intensity of hypoxia have increased with anthropogenic eutrophication due to nutrient inputs. Physical processes, which control stratification and the renewal of oxygen in bottom waters, are important constraints on the formation and maintenance of hypoxia. Climate controlled inflows of saline water from the North Sea through the Danish Straits is a critical controlling factor governing the spatial extent and duration of hypoxia. Hypoxia regulates the biogeochemical cycles of both phosphorus (P) and nitrogen (N) in the water column and sediments. Significant amounts of P are currently released from sediments, an order of magnitude larger than anthropogenic inputs. The Baltic Sea is unique for coastal marine ecosystems experiencing N losses in hypoxic waters below the halocline. Although benthic communities in the Baltic Sea are naturally constrained by salinity gradients, hypoxia has resulted in habitat loss over vast areas and the elimination of benthic fauna, and has severely disrupted benthic food webs. Nutrient load reductions are needed to reduce the extent, severity, and effects of hypoxia.
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| 2. |
- Prikhna, Tatjana A., et al.
(författare)
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High-pressure synthesized nanostructural MgB2 materials with high performance of superconductivity, suitable for fault current limitation and other applications
- 2011
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Ingår i: IEEE transactions on applied superconductivity (Print). - 1051-8223 .- 1558-2515. ; 21:3, s. 2694-2697
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Tidskriftsartikel (refereegranskat)abstract
- A variety of samples made via different routes were investigated. Samples are nanostructured (average grain sizes are about 20 nm). The advantage of high-pressure (HP)-manufactured (2 GPa, 800-1050 degrees C, 1 h) MgB2 bulk is the possibility to get almost theoretically dense (1-2% porosity) material with very high critical current densities reaching at 20 K, in 0-1 T j(c) = 1.2 - 1.0 . 10(6) A/cm(2) (with 10% SiC doping) and j(c) = 9.2 - 7.3 10(5) A/cm(2) (without doping). Mechanical properties are also very high: fracture toughness up to 4.4 +/- 0.04 MPa . m(0.5) and 7.6 +/- 2.0 MPa . m(0.5) at 148.8 N load for MgB2 undoped and doped with 10% Ta, respectively. The HP-synthesized material at moderate temperature (2 GPa, 600 degrees C, 1 h) from B with high amount of impurity C (3.15%) and H (0.87%) has j(c) = 10(3) A/cm(2) in 8 T field at 20 K, highest irreversibility fields (at 18.4 K H-irr = 15 T) and upper critical fields (at 22 K H-C2 = 15 T) but 17% porosity. HP materials with stoichiometry near MgB12 can have T-c = 37 K and j(c) = 6 . 10(4) A/cm(2) at 0 T and H-irr = 5 T at 20 K. The spark plasma synthesized (SPS) material (50 MPa, 600-1050 degrees C 1.3 h, without additions), demonstrated at 20 K, in 0-1 T j(c) = 4.5 - 4 10(5) A/cm(2). Dispersed inclusions of higher magnesium borides, which are usually present in MgB2 structure and obviously create new pinning centers can be revealed by Raman spectroscopy (for the first time a spectrum of MgB7 was obtained). Tests of quench behavior, losses on MgB2 rings and material thermal conductivity show promising properties for fault current limiters. Due to high critical fields, the material can be used for magnets.
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| 3. |
- Prikhna, T., et al.
(författare)
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Effects of high pressure on the physical properties of MgB2
- 2011
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Ingår i: Journal of Superconductivity and Novel Magnetism. - : Springer Science and Business Media LLC. - 1557-1939 .- 1557-1947. ; 24:5, s. 137-150
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis of MgB2-based materials under high pressure gave the possibility to suppress the evaporation of magnesium and to obtain near theoretically dense nanograined structures with high superconducting, thermal conducting, and mechanical characteristics: critical current densities of 1.8-1.0×106 A/cm2 in the self-field and 103 A/cm2 in a magnetic field of 8 T at 20 K, 5-3×105 A/cm2 in self-field at 30 K, the corresponding critical fields being Hc2=15 T at 22 K and irreversible fields Hirr=13 T at 20 K, and Hirr=3.5 T at 30 K, thermal conduction of 53±2 W/(m{dot operator}K), the Vickers hardness HV=10.12±0.2 GPa under a load of 148.8 N and the fracture toughness K1 C=7.6±2.0 MPa{dot operator}m0.5 under the same load, the Young modulus E=213 GPa. Estimation of quenching current and AC losses allowed the conclusion that high-pressure-prepared materials are promising for application in transformer-type fault current limiters working at 20-30 K.
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| 4. |
- Revankar, C. M., et al.
(författare)
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A Selective Ligand for Estrogen Receptor Proteins Discriminates Rapid and Genomic Signaling
- 2019
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Ingår i: Cell Chemical Biology. - : Elsevier BV. - 2451-9448 .- 2451-9456. ; 26:12
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Tidskriftsartikel (refereegranskat)abstract
- Estrogen exerts extensive and diverse effects throughout the body of women. In addition to the classical nuclear estrogen receptors (ER alpha and ER beta), the G protein-coupled estrogen receptor GPER is an important mediator of estrogen action. Existing ER-targeted therapeutic agents act as GPER agonists. Here, we report the identification of a small molecule, named AB-1, with the previously unidentified activity of high selectivity for binding classical ERs over GPER. AB-1 also possesses a unique functional activity profile as an agonist of transcriptional activity but an antagonist of rapid signaling through ER alpha. Our results define a class of small molecules that discriminate between the classical ERs and GPER, as well as between modes of signaling within the classical ERs. Such an activity profile, if developed into an ER antagonist, could represent an opportunity for the development of first-in-class nuclear hormone receptor-targeted therapeutics for breast cancer exhibiting reduced acquired and de novo resistance.
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| 5. |
- Meier, Markus, et al.
(författare)
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Comparing reconstructed past variations and future projections of the Baltic sea ecosystem first results from multi model ensemble simulations
- 2012
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 7:3, s. 034005-
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Tidskriftsartikel (refereegranskat)abstract
- Multi-model ensemble simulations for the marine biogeochemistry and food web of the Baltic Sea were performed for the period 1850-2098, and projected changes in the future climate were compared with the past climate environment. For the past period 1850-2006, atmospheric, hydrological and nutrient forcings were reconstructed, based on historical measurements. For the future period 1961-2098, scenario simulations were driven by regionalized global general circulation model (GCM) data and forced by various future greenhouse gas emission and air-and riverborne nutrient load scenarios (ranging from a pessimistic 'business-as-usual' to the most optimistic case). To estimate uncertainties, different models for the various parts of the Earth system were applied. Assuming the IPCC greenhouse gas emission scenarios A1B or A2, we found that water temperatures at the end of this century may be higher and salinities and oxygen concentrations may be lower than ever measured since 1850. There is also a tendency of increased eutrophication in the future, depending on the nutrient load scenario. Although cod biomass is mainly controlled by fishing mortality, climate change together with eutrophication may result in a biomass decline during the latter part of this century, even when combined with lower fishing pressure. Despite considerable shortcomings of state-of-the-art models, this study suggests that the future Baltic Sea ecosystem may unprecedentedly change compared to the past 150 yr. As stakeholders today pay only little attention to adaptation and mitigation strategies, more information is needed to raise public awareness of the possible impacts of climate change on marine ecosystems.
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| 6. |
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| 7. |
- Ryabchenko, V. A., et al.
(författare)
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Model estimates of the eutrophication of the Baltic Sea in the contemporary and future climate
- 2016
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Ingår i: Oceanology. - 0001-4370 .- 1531-8508. ; 56:1, s. 36-45
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Tidskriftsartikel (refereegranskat)abstract
- The St. Petersburg Baltic eutrophication model (SPBEM) is used to assess the ecological condition of the sea under possible changes in climate and nutrient loads in the 21st century. According to model estimates, in the future climate water quality will worsen, compared to modern conditions. This deterioration is stronger in the climate warming scenario with a stronger change in future near-surface air temperature. In the considered scenarios of climate change, climate warming will lead to an increase in the area of anoxic and hypoxic zones. Reduction of nutrient loading, estimated in accordance with the Baltic Sea Action Plan, will only be able to partially compensate for the negative effects of global warming.
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