| 1. |
- Lappalainen, Hanna K., et al.
(författare)
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Pan-Eurasian Experiment (PEEX) : towards a holistic understanding of the feedbacks and interactions in the land-atmosphere-ocean-society continuum in the northern Eurasian region
- 2016
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 16:22, s. 14421-14461
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Tidskriftsartikel (refereegranskat)abstract
- The northern Eurasian regions and Arctic Ocean will very likely undergo substantial changes during the next decades. The Arctic-boreal natural environments play a crucial role in the global climate via albedo change, carbon sources and sinks as well as atmospheric aerosol production from biogenic volatile organic compounds. Furthermore, it is expected that global trade activities, demographic movement, and use of natural resources will be increasing in the Arctic regions. There is a need for a novel research approach, which not only identifies and tackles the relevant multi-disciplinary research questions, but also is able to make a holistic system analysis of the expected feedbacks. In this paper, we introduce the research agenda of the Pan-Eurasian Experiment (PEEX), a multi-scale, multi-disciplinary and international program started in 2012 (https://www.atm.helsinki.fi/peex/). PEEX sets a research approach by which large-scale research topics are investigated from a system perspective and which aims to fill the key gaps in our understanding of the feedbacks and interactions between the land-atmosphereaquatic-society continuum in the northern Eurasian region. We introduce here the state of the art for the key topics in the PEEX research agenda and present the future prospects of the research, which we see relevant in this context.
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| 2. |
- Lukashevich, M.G., et al.
(författare)
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Magnetoresistive effect in PET films with iron nanoparticles synthesised by ion implantation
- 2010
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Ingår i: The Open Applied Physics Journal. - 1874-1835. ; 3, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- Thin polyethyleneterephthalate (PET) layers with Fe nanoparticles (NPs) were synthesised by high-fluence ion implantation. Temperature dependence of conductance and magnetoresitance were studied as a function of ion fluence. It is found that the implantation with fluences of about 1.0×1017 cm-2 causes high enough concentration of metal inclusions to provide conditions for electrical percolation that leads to an insulator-to-metal transition (IMT) in charge carrier transport mechanisms. The magnetoresistance measurements indicate that the magnetic percolation takes place at metal concentrations (fluences) lower than those needed for the electrical percolation. For the samples on insulating side of the IMT, a non-monotonous dependence of resistance in an increasing external magnetic field is observed due to anisotropic magnetoresistive effect and charge carrier scattering on magnetic inclusions. For the samples implanted with fluences > 1.0×1017 cm-2, the magnetoresistance becomes a monotonous decreasing function of the external magnetic field which is typical for ferromagnetic metals that indicates effective magnetic coupling of the iron inclusions.
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| 3. |
- Schierholz, Léon, et al.
(författare)
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A conserved ribosomal protein has entirely dissimilar structures in different organisms
- 2024
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Ingår i: Molecular biology and evolution. - : Oxford University Press. - 0737-4038 .- 1537-1719. ; 41:1
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Tidskriftsartikel (refereegranskat)abstract
- Ribosomes from different species can markedly differ in their composition by including dozens of ribosomal proteins that are unique to specific lineages but absent in others. However, it remains unknown how ribosomes acquire new proteins throughout evolution. Here, to help answer this question, we describe the evolution of the ribosomal protein msL1/msL2 that was recently found in ribosomes from the parasitic microorganism clade, microsporidia. We show that this protein has a conserved location in the ribosome but entirely dissimilar structures in different organisms: in each of the analyzed species, msL1/msL2 exhibits an altered secondary structure, an inverted orientation of the N-Termini and C-Termini on the ribosomal binding surface, and a completely transformed 3D fold. We then show that this fold switching is likely caused by changes in the ribosomal msL1/msL2-binding site, specifically, by variations in rRNA. These observations allow us to infer an evolutionary scenario in which a small, positively charged, de novo-born unfolded protein was first captured by rRNA to become part of the ribosome and subsequently underwent complete fold switching to optimize its binding to its evolving ribosomal binding site. Overall, our work provides a striking example of how a protein can switch its fold in the context of a complex biological assembly, while retaining its specificity for its molecular partner. This finding will help us better understand the origin and evolution of new protein components of complex molecular assemblies-thereby enhancing our ability to engineer biological molecules, identify protein homologs, and peer into the history of life on Earth.
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| 4. |
- Tolmachev, Vladimir A., et al.
(författare)
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Optical Spectra of Composite One-Dimensional Photonic Crystals With Extended Stop Bands Based on a Si-Air Structure
- 2015
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 33:17, s. 3577-3583
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Tidskriftsartikel (refereegranskat)abstract
- The optical spectra of composite one-dimensional photonic crystals (1-D PCs), fabricated by microstructuring of Si, are investigated. The composite PC is based on a Si-air structure and consists of two periodic 1-D PCs with various lattice constants a with a(1) = 2.7 mu m and a(2) = 4 mu m and various filling fractions f. The PCs are fabricated using photolithography followed by anisotropic chemical etching of (1 1 0) Si. Reflection and transmission spectra of this structure are measured using a Fourier transform infrared spectrometer combined with an IR microscope. The transmission spectra obtained demonstrate extended photonic stop bands (SBs), with characteristic transmission bands between the SBs. Theoretical and experimental transmission results indicate that the position of the extended SBs does not depend on the sequence of the individual PCs within the composite structure. In general, the calculated electric field distribution in the composite structure is similar to that of the individual PC components.
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