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- Zhao, Yanyan, et al.
(författare)
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A 30,000-km journey by Apus apus pekinensis tracks arid lands between northern China and south-western Africa
- 2022
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Ingår i: Movement Ecology. - : Springer Science and Business Media LLC. - 2051-3933. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Background: As a widely distributed and aerial migratory bird, the Common Swift (Apus apus) flies over a wide geographic range in Eurasia and Africa during migration. Although some studies have revealed the migration routes and phenology of European populations, A. a. apus (from hereon the nominate apus), the route used by its East Asian counterpart A. a. pekinensis (from hereon pekinensis) remained a mystery. Methods: Using light level geolocators, we studied the migration of adult pekinensis breeding in Beijing from 2014 to 2018, and analysed full annual tracks obtained from 25 individuals. In addition, we used the mean monthly precipitation to assess the seasonal variations in humidity for the distribution ranges of the nominate apus and pekinensis. This environmental variable is considered to be critically relevant to their migratory phenology and food resource abundance. Results: Our results show that the swifts perform a round-trip journey of ca 30,000 km each year, representing a detour of 26% in autumn and 15% in spring compared to the shortest route between the breeding site in Beijing and wintering areas in semi-arid south-western Africa. Compared to the nominate apus, pekinensis experiences drier conditions for longer periods of time. Remarkably, individuals from our study population tracked arid habitat along the entire migration corridor leading from a breeding site in Beijing to at least central Africa. In Africa, they explored more arid habitats during non-breeding than the nominate apus. Conclusions: The migration route followed by pekinensis breeding in Beijing might suggest an adaptation to semi-arid habitat and dry climatic zones during non-breeding periods, and provides a piece of correlative evidence indicating the historical range expansion of the subspecies. This study highlights that the Common Swift may prove invaluable as a model species for studies of migration route formation and population divergence.
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| 2. |
- Lei, Chengan, et al.
(författare)
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Controllable dual-polarization valley physics in the strain-engineered 2D monolayer of VC2N4
- 2024
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Ingår i: Journal of Materials Chemistry C. - : Royal Society of Chemistry. - 2050-7526 .- 2050-7534. ; 12:6, s. 2156-2164
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Tidskriftsartikel (refereegranskat)abstract
- Valley-related physics has garnered significant attention in fundamental studies and cutting-edge information technologies. However, such valleytronic materials have rarely been reported and suffer from in-plane magnetization. Herein, based on first-principles calculations and tight-binding model analysis, we identify the existence of intrinsic valley-contrasting physics in bipolar ferromagnetic monolayer VC2N4 with robust perpendicular magnetic anisotropy behavior. Valley polarization arises spontaneously due to the simultaneous presence of broken space- and time-inversion symmetries. Interestingly, valley polarization is remarkably observed in both the valence and conduction bands around the K/K′ valley due to large spin splitting, indicating rare dual-polarization valley features, which is advantageous for achieving the captivating anomalous valley Hall effect relied on the valley-contrasting Berry curvature. Remarkably, the valley polarization can be switched on/off by applying a moderate biaxial strain. Our work provides a competitive candidate for exploring valley-dependent physics and its applications in valleytronics.
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| 3. |
- Rems, Lea, et al.
(författare)
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Identification of electroporation sites in the complex lipid organization of the plasma membrane
- 2022
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Ingår i: eLIFE. - : eLife Sciences Publications, Ltd. - 2050-084X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- The plasma membrane of a biological cell is a complex assembly of lipids and membrane proteins, which tightly regulate transmembrane transport. When a cell is exposed to strong electric field, the membrane integrity becomes transiently disrupted by formation of transmembrane pores. This phenomenon termed electroporation is already utilized in many rapidly developing applications in medicine including gene therapy, cancer treatment, and treatment of cardiac arrhythmias. However, the molecular mechanisms of electroporation are not yet sufficiently well understood; in particular, it is unclear where exactly pores form in the complex organization of the plasma membrane. In this study, we combine coarse-grained molecular dynamics simulations, machine learning methods, and Bayesian survival analysis to identify how formation of pores depends on the local lipid organization. We show that pores do not form homogeneously across the membrane, but colocalize with domains that have specific features, the most important being high density of polyunsaturated lipids. We further show that knowing the lipid organization is sufficient to reliably predict poration sites with machine learning. Additionally, by analysing poration kinetics with Bayesian survival analysis we show that poration does not depend solely on local lipid arrangement, but also on membrane mechanical properties and the polarity of the electric field. Finally, we discuss how the combination of atomistic and coarse-grained molecular dynamics simulations, machine learning methods, and Bayesian survival analysis can guide the design of future experiments and help us to develop an accurate description of plasma membrane electroporation on the whole-cell level. Achieving this will allow us to shift the optimization of electroporation applications from blind trial-and-error approaches to mechanistic-driven design.
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