| 1. |
- Kaufmann, Tobias, et al.
(author)
-
Common brain disorders are associated with heritable patterns of apparent aging of the brain
- 2019
-
In: Nature Neuroscience. - : Nature Publishing Group. - 1097-6256 .- 1546-1726. ; 22:10, s. 1617-
-
Journal article (peer-reviewed)abstract
- Common risk factors for psychiatric and other brain disorders are likely to converge on biological pathways influencing the development and maintenance of brain structure and function across life. Using structural MRI data from 45,615 individuals aged 3-96 years, we demonstrate distinct patterns of apparent brain aging in several brain disorders and reveal genetic pleiotropy between apparent brain aging in healthy individuals and common brain disorders.
|
|
| 2. |
- Alves, Guido, et al.
(author)
-
Cerebrospinal fluid amyloid-β and phenotypic heterogeneity in de novo Parkinson's disease.
- 2013
-
In: Journal of neurology, neurosurgery, and psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 84:5, s. 537-43
-
Journal article (peer-reviewed)abstract
- In Parkinson's disease (PD), the motor presentation characterised by postural instability/gait difficulties (PIGD) heralds accelerated motor, functional and cognitive decline, as compared with the more benign tremor-dominant (TD) variant. This makes the PIGD complex an attractive target for the discovery of prognostic biomarkers in PD.
|
|
| 3. |
- Balk, Lennart, et al.
(author)
-
Biomarkers in Natural Fish Populations Indicate Adverse Biological Effects of Offshore Oil Production
- 2011
-
In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:5, s. e19735-
-
Journal article (peer-reviewed)abstract
- Background: Despite the growing awareness of the necessity of a sustainable development, the global economy continues to depend largely on the consumption of non-renewable energy resources. One such energy resource is fossil oil extracted from the seabed at offshore oil platforms. This type of oil production causes continuous environmental pollution from drilling waste, discharge of large amounts of produced water, and accidental spills. Methods and principal findings: Samples from natural populations of haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua) in two North Sea areas with extensive oil production were investigated. Exposure to and uptake of polycyclic aromatic hydrocarbons (PAHs) were demonstrated, and biomarker analyses revealed adverse biological effects, including induction of biotransformation enzymes, oxidative stress, altered fatty acid composition, and genotoxicity. Genotoxicity was reflected by a hepatic DNA adduct pattern typical for exposure to a mixture of PAHs. Control material was collected from a North Sea area without oil production and from remote Icelandic waters. The difference between the two control areas indicates significant background pollution in the North Sea. Conclusion: It is most remarkable to obtain biomarker responses in natural fish populations in the open sea that are similar to the biomarker responses in fish from highly polluted areas close to a point source. Risk assessment of various threats to the marine fish populations in the North Sea, such as overfishing, global warming, and eutrophication, should also take into account the ecologically relevant impact of offshore oil production.
|
|
| 4. |
|
|
| 5. |
- Beyer, Jan, et al.
(author)
-
Effects of a longitudinal magnetic field on spin injection and detection in InAs/GaAs quantum dot structures
- 2012
-
In: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 24:14, s. 145304-
-
Journal article (peer-reviewed)abstract
- Effects of a longitudinal magnetic field on optical spin injection and detection in InAs/GaAs quantum dot (QD) structures are investigated by optical orientation spectroscopy. An increase in optical and spin polarization of the QDs is observed with increasing magnetic field in the range of 0-2 T, and is attributed to suppression of exciton spin depolarization within the QDs that is promoted by hyperfine interaction and anisotropic electron-hole exchange interaction. This leads to a corresponding enhancement in spin detection efficiency of the QDs by a factor of up to 2.5. At higher magnetic fields when these spin depolarization processes are quenched, electron spin polarization in anisotropic QD structures (such as double QDs that are preferably aligned along a specific crystallographic axis) still exhibits rather strong field dependence under non-resonant excitation. In contrast, such field dependence is practically absent in more "isotropic" QD structures (e.g. single QDs). We attribute the observed effect to stronger electron spin relaxation in the spin injectors (i.e. wetting layer and GaAs barriers) of the lower-symmetry QD structures, which also explains the lower spin injection efficiency observed in these structures.
|
|
| 6. |
|
|
| 7. |
- Beyer, Jan, 1980-, et al.
(author)
-
Efficiency of spin injection in novel InAs quantum dotstructures: exciton vs. free carrier injection
- 2010
-
Conference paper (peer-reviewed)abstract
- Unambiguous experimental evidence for a significant difference in efficiency of excitonic vs. free carrier spin injection is provided in novel laterally arranged self-assembled InAs/GaAs quantum dot structures, from optical orientation and tunable laser spectroscopy. A lower efficiency of exciton spin injection as compared to free carrier spin injection from wetting layers into QDs results in a distinct feature in luminescence polarization of the QDs as a function of excitation photon energy. It is shown that this difference is not related to carrier density and state-filling effects arising from the difference in optical absorption efficiency between the excitons and free carriers. Rather, it is a genuine property for exciton spin injection that suffers stronger spin relaxation due to Coulomb exchange interaction.
|
|
| 8. |
- Beyer, Jan, 1980-, et al.
(author)
-
Free-carriers beat excitons in spin-injection contest
- 2009
-
Other publication (pop. science, debate, etc.)abstract
- Quantum dots (QDs) are a promising building block for future spin-functional devices with applications in spintronics and quantum information processing. Essential to the success of these devices is the ability to create a desired spin orientation of charge carriers (electrons and holes) in QDs via the injection of spin-polarized carriers. Researchers have now shown that this can be done most efficiently using independent (free) carriers rather than electron-hole pairs (excitons).
|
|
| 9. |
- Beyer, Jan, et al.
(author)
-
Hanle effect and electron spin polarization in InAs/GaAs quantum dots up to room temperature
- 2012
-
In: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 23:13, s. 135705-
-
Journal article (peer-reviewed)abstract
- Hanle effect in InAs/GaAs quantum dots (QDs) is studied under optical orientation as a function of temperature over the range of 150-300 K, with the aim to understand the physical mechanism responsible for the observed sharp increase of electron spin polarization with increasing temperature. The deduced spin lifetime Ts of positive trions in the QDs is found to be independent of temperature, and is also insensitive to excitation energy and density. It is argued that the measured Ts is mainly determined by the longitudinal spin flip time (T1) and the spin dephasing time (T2 *) of the studied QD ensemble, of which both are temperatureindependent over the studied temperature range and the latter makes a larger contribution. The observed sharply rising of the QD spin polarization degree with increasing temperature, on the other hand, is shown to be induced by an increase in spin injection efficiency from the barrier/wetting layer and also by a moderate increase in spin detection efficiency of the QD.
|
|
| 10. |
|
|
