| 1. |
- Lind, Johan, et al.
(författare)
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Split-second escape decisions in blue tits (Parus caeruleus)
- 2002
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Ingår i: Die Naturwissenschaften. - : Springer Science and Business Media LLC. - 0028-1042 .- 1432-1904. ; 89:9, s. 420-423
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Tidskriftsartikel (refereegranskat)abstract
- Bird mortality is heavily affected by birds of prey. Under attack, take-off is crucial for survival and even minor mistakes in initial escape response can have devastating consequences. Birds may respond differently depending on the character of the predator's attack and these split-second decisions were studied using a model merlin (Falco columbarius) that attacked feeding blue tits (Parus caeruleus) from two different attack angles in two different speeds. When attacked from a low attack angle they took off more steeply than when attacked from a high angle. This is the first study to show that escape behaviour also depends on predator attack speed. The blue tits responded to a high-speed attack by dodging sideways more often than when attacked at a low speed. Escape speed was not significantly affected by the different treatments. Although they have only a split-second before escaping an attack, blue tits do adjust their escape strategy to the prevailing attack conditions.
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| 2. |
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| 3. |
- Mirzov, Oleg, et al.
(författare)
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Direct exciton quenching in single molecules of MEH-PPV at 77 K
- 2004
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 386:4-6, s. 286-290
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Tidskriftsartikel (refereegranskat)abstract
- Fluorescence blinking behaviour was observed for single molecules of the conjugated polymer poly[2-methoxy,5-(2'-ethylhexyloxy)-p-phenylene-vinylene] (MEH-PPV) at 77 and 300 K. No strict qualitative dependence on temperature was observed, despite of the expected suppression of exciton migration at the low temperature. We assume MEH-PPV molecules to form dense nanoparticles with a characteristic size of about 10 nm at the largest. In such small nanoparticles exciton can be efficiently quenched by a photogenerated quencher due to Forster transfer just after a few hops over the polymer nanoparticle. Thus, long-distance exciton migration is not necessary to have strong fluorescence intensity fluctuations. (C) 2004 Elsevier B.V. All rights reserved.
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| 4. |
- Rodriguez, G, et al.
(författare)
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Regional cerebral blood flow asymmetries in a group of 189 normal subjects at rest
- 1991
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Ingår i: Brain Topography. - 0896-0267 .- 1573-6792. ; 4:1, s. 57-63
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Tidskriftsartikel (refereegranskat)abstract
- Regional cerebral blood flow (rCBF) asymmetries were studied in 189 subjects (96 males and 93 females) at rest with the 133Xenon inhalation method using a fixed detector system. rCBF asymmetries in the resting condition were very small, nevertheless a significant (p less than 0.001) effect for their topographical distribution was present, reflecting higher rCBF in the right fronto-temporal and left parieto-occipital regions. rCBF asymmetries were not correlated with age, and there were no significant differences between males and females. Asymmetries are therefore useful from a statistical point of view in detecting rCBF abnormalities in the resting condition: they are more stable than absolute values in normal subjects and no matching according to age or sex is required when statistical comparisons are performed.
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| 5. |
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| 6. |
- Ezer, Shlomit, et al.
(författare)
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Infantile SOD1 deficiency syndrome caused by a homozygous SOD1 variant with absence of enzyme activity
- 2022
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Ingår i: Brain. - : Oxford University Press. - 0006-8950 .- 1460-2156. ; 145:3, s. 872-878
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Tidskriftsartikel (refereegranskat)abstract
- Pathogenic variants in SOD1, encoding superoxide dismutase 1, are responsible for about 20% of all familial amyotrophic lateral sclerosis cases, through a gain-of-function mechanism. Recently, two reports showed that a specific homozygous SOD1 loss-of-function variant is associated with an infantile progressive motor-neurological syndrome. Exome sequencing followed by molecular studies, including cDNA analysis, SOD1 protein levels and enzymatic activity, and plasma neurofilament light chain levels, were undertaken in an infant with severe global developmental delay, axial hypotonia and limb spasticity. We identified a homozygous 3-bp in-frame deletion in SOD1. cDNA analysis predicted the loss of a single valine residue from a tandem pair (p.Val119/Val120) in the wild-type protein, yet expression levels and splicing were preserved. Analysis of SOD1 activity and protein levels in erythrocyte lysates showed essentially no enzymatic activity and undetectable SOD1 protein in the child, whereas the parents had ∼50% protein expression and activity relative to controls. Neurofilament light chain levels in plasma were elevated, implying ongoing axonal injury and neurodegeneration. Thus, we provide confirmatory evidence of a second biallelic variant in an infant with a severe neurological syndrome and suggest that the in-frame deletion causes instability and subsequent degeneration of SOD1. We highlight the importance of the valine residues at positions V119-120, and suggest possible implications for future therapeutics research.
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| 7. |
- Zhivotovsky, B, et al.
(författare)
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Apoptosis and genomic instability
- 2004
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Ingår i: Nature reviews. Molecular cell biology. - : Springer Science and Business Media LLC. - 1471-0072 .- 1471-0080. ; 5:9, s. 752-762
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Zhirkov, Igor, et al.
(författare)
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Ion velocities in direct current arc plasma generated from compound cathodes211102
- 2013
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 114:21, s. 213302-
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Tidskriftsartikel (refereegranskat)abstract
- Arc plasma from Ti-C, Ti-Al, and Ti-Si cathodes was characterized with respect to charge-state-resolved ion energy. The evaluated peak velocities of different ion species in plasma generated from a compound cathode were found to be equal and independent on ion mass. Therefore, measured difference in kinetic energies can be inferred from the difference in ion mass, with no dependence on ion charge state. The latter is consistent with previous work. These findings can be explained by plasma quasineutrality, ion acceleration by pressure gradients, and electron-ion coupling. Increasing the C concentration in Ti-C cathodes resulted in increasing average and peak ion energies for all ion species. This effect can be explained by the "cohesive energy rule," where material and phases of higher cohesive energy generally result in increasing energies (velocities). This is also consistent with the here obtained peak velocities around 1.37, 1.42, and 1.55 (10(4) m/s) for ions from Ti0.84Al0.16, Ti0.90Si0.10, and Ti0.90C0.10 cathodes, respectively.
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| 9. |
- Benstead, Lindsay, et al.
(författare)
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Using Tablet Computers to Implement Surveys in Challenging Environments
- 2017
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Ingår i: Survey Practice. - 2168-0094. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Computer-assisted personal interviewing (CAPI) has increasingly been used in developing countries, but literature and training on best practices have not kept pace. Drawing on our experiences using CAPI to implement the Local Governance Performance Index (LGPI) in Tunisia and Malawi and an election study in Jordan, this paper makes practical recommendations for mitigating challenges and leveraging CAPI’s benefits to obtain high quality data. CAPI offers several advantages. Tablets facilitate complex skip patterns and randomization of long question batteries and survey experiments, which helps to reduce measurement error. Tablets’ global positioning system (GPS) technology reduces sampling error by locating sampling units and facilitating analysis of neighborhood effects. Immediate data uploading, time-stamps for individual questions, and interview duration capture allowed real time data quality checks and interviewer monitoring. Yet, CAPI entails challenges, including costs of learning new software; questionnaire programming; and piloting to resolve coding bugs; and ethical and logistical considerations, such as electricity and Internet connectivity.
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| 10. |
- Di Bari, Chiara, et al.
(författare)
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Fabrication of high surface area graphene electrodes with high performance towards enzymatic oxygen reduction
- 2016
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Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 191, s. 500-509
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Tidskriftsartikel (refereegranskat)abstract
- High surface area graphene electrodes were prepd. by simultaneous electrodeposition and electroredn. of graphene oxide. The electrodeposition process was optimized in terms of pH and cond. of the soln. and the obtained graphene electrodes were characterized by XPS, FTIR spectroscopy, SEM and electrochem. methods (cyclic voltammetry and impedance spectroscopy). Electrodeposited electrodes were further functionalized to carry out covalent immobilization of two O-reducing multicopper oxidases: laccase and bilirubin oxidase. The enzymic electrodes were tested as direct electron transfer based biocathodes and catalytic currents ≤1 mA/cm2 were obtained. Finally, the mechanism of the enzymic O redn. reaction was studied for both enzymes calcg. the Tafel slopes and transfer coeffs.
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