| 1. |
- Ehrich, Dorothee, et al.
(författare)
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Documenting lemming population change in the Arctic : Can we detect trends?
- 2020
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 49:3, s. 786-800
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Tidskriftsartikel (refereegranskat)abstract
- Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective.
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| 2. |
- Parunova, Yulia, et al.
(författare)
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Potentially implantable biocathode with the function of charge accumulation based on nanocomposite of polyaniline/carbon nanotubes
- 2016
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Ingår i: Russian journal of electrochemistry. - : Springer. - 1023-1935 .- 1608-3342. ; 52:12, s. 1166-1171
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Tidskriftsartikel (refereegranskat)abstract
- A potentially implantable biocathode with the function of charge accumulation based on a nanobiocomposite including multiwall carbon nanotubes, polyaniline, and bilirubin oxidase is developed. The regularities of the functioning of the obtained electrode are studied in air-satd. phosphate buffer soln., pH 7.4 (PB), and also in phosphate buffer soln. contg. redox-active blood components (BMB). The open circuit potential of the biocathode is 0.33 and 0.08 V vs. the SCE in PB and BMB, resp.; it is completely restored after at least three self-charge/discharge cycles with connection to resistors with different resistance. Bioelectrocatalytic c.d. of oxygen redn. is 0.50 and 0.42 mA cm-2 with the residual activity of 78 and 60% of the initial value after 12 h of continuous operation in PB at 25°C and in BMB at 37°C, resp.
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| 3. |
- Sergeyev, Sergey V., et al.
(författare)
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Dissipative vector solitons with fast evolving states of polarization
- 2014
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Ingår i: Nonlinear Photonics, NP. - Washington, D.C. : OSA. - 9781557528209
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Konferensbidrag (refereegranskat)abstract
- We report on a new vector model of an erbium doped fiber laser mode locked with carbon nanotubes. This model goes beyond the limitations of the previously used models based on either coupled nonlinear Schrödinger or Ginzburg-Landau equations. It results in a new family of vector solitons with fast evolving states of polarization experimentally observed in our previous papers.
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| 4. |
- Sergeyev, Sergey V., et al.
(författare)
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Vector solitons in mode locked fibre lasers
- 2014
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Ingår i: International Conference on Transparent Optical Networks. - : IEEE. - 9781479956005 - 9781479956012
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Konferensbidrag (refereegranskat)abstract
- We overview our recent results on polarisation dynamics of vector solitons in erbium doped fibre laser mode locked with carbon nanotubes. Our experimental and theoretical study revealed new families of vector solitons for fundamental and bound-state soliton operations. The observed scenario of the evolution of the states of polarisation (SOPs) on the Poincare sphere includes fast polarisation switching between two and three SOPs along with slow SOP evolution on a double scroll chaotic attractor. The underlying physics presents an interplay between effects of birefringence of the laser cavity and light induced anisotropy caused by polarisation hole burning.
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| 5. |
- Andoralov, Viktor, et al.
(författare)
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Biofuel cell based on microscale nanostructured electrodes with inductive coupling to rat brain neurons
- 2013
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; :3
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Tidskriftsartikel (refereegranskat)abstract
- Miniature, self-contained biodevices powered by biofuel cells may enable a new generation of implantable, wireless, minimally invasive neural interfaces for neurophysiological in vivo studies and for clinical applications. Here we report on the fabrication of a direct electron transfer based glucose/oxygen enzymatic fuel cell (EFC) from genuinely three-dimensional (3D) nanostructured microscale gold electrodes, modified with suitable biocatalysts. We show that the process underlying the simple fabrication method of 3D nanostructured electrodes is based on an electrochemically driven transformation of physically deposited gold nanoparticles. We experimentally demonstrate that mediator-, cofactor-, and membrane-less EFCs do operate in cerebrospinal fluid and in the brain of a rat, producing amounts of electrical power sufficient to drive a self-contained biodevice, viz. 7 μW cm−2 in vitro and 2 μW cm−2 in vivo at an operating voltage of 0.4 V. Last but not least, we also demonstrate an inductive coupling between 3D nanobioelectrodes and living neurons.
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| 6. |
- Andoralov, Victor, et al.
(författare)
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Octaheme nitrite reductase : The mechanism of intramolecular electron transfer and kinetics of nitrite bioelectroreduction.
- 2021
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Ingår i: Bioelectrochemistry. - : Elsevier. - 1567-5394 .- 1878-562X. ; 138
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Tidskriftsartikel (refereegranskat)abstract
- Detailed impedance and voltammetric studies of hexameric octaheme nitrite reductase immobilized on carbon-based nanomaterials, specifically nanotubes and nanoparticles, were performed. Well-pronounced bioelectrocatalytic reduction of nitrite on enzyme-modified electrodes was obtained. Analysis of the impedance data indicated the absence of long-lived intermediates involved in the nitrite reduction. Cyclic voltammograms of biomodified electrodes had a bi-sigmoidal shape, which pointed to the presence of two enzyme orientations on carbon supports. The maximum (limiting) catalytic currents were determined and, by applying the correction by the mixed kinetics equation, the Tafel dependences were plotted for each catalytic wave/each enzyme orientation. Finally, two schemes for the rate-limiting processes during bioelectrocatalysis were proposed, viz. for low- and high-potential orientations.
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| 7. |
- Baenas, Isabel, et al.
(författare)
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Impact of COVID-19 Lockdown in Eating Disorders : A Multicentre Collaborative International Study
- 2022
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background. The COVID-19 lockdown has had a significant impact on mental health. Patients with eating disorders (ED) have been particularly vulnerable. Aims. (1) To explore changes in eating-related symptoms and general psychopathology during lockdown in patients with an ED from various European and Asian countries; and (2) to assess differences related to diagnostic ED subtypes, age, and geography. Methods. The sample comprised 829 participants, diagnosed with an ED according to DSM-5 criteria from specialized ED units in Europe and Asia. Participants were assessed using the COVID-19 Isolation Scale (CIES). Results. Patients with binge eating disorder (BED) experienced the highest impact on weight and ED symptoms in comparison with other ED subtypes during lockdown, whereas individuals with other specified feeding and eating disorders (OFSED) had greater deterioration in general psychological functioning than subjects with other ED subtypes. Finally, Asian and younger individuals appeared to be more resilient. Conclusions. The psychopathological changes in ED patients during the COVID-19 lockdown varied by cultural context and individual variation in age and ED diagnosis. Clinical services may need to target preventive measures and adapt therapeutic approaches for the most vulnerable patients.
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| 8. |
- Baitenov, Adil, 1994-
(författare)
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Light propagation and photonic functionalization of semi-ordered material (transparent wood)
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Investigating novel materials requires understanding their chemical and optical properties, which allows for finding their uses through functionalization by chemical modification. In this thesis, we are focusing on a material with high anisotropic scattering - transparent wood. This biocomposite material has a hierarchical structure ranging from nanometer to hundreds of micrometers scale, and natural ordering, which is between perfectly ordered and fully random structure. Optical transparency in the visible range and the unique structure of transparent woods show good potential for functionalization. Due to complex structure and nonhomogenous chemical composition, not all characterization methods are fitting. While relatively straightforward properties like transmittance and haze can be measured using known techniques, but additional investigation was required to understand light behavior and measure other properties. In this work, the modeling method for investigation of light propagation and estimation of the effective refractive index of transparent wood for a deeper understanding of a material. Transparent wood has shown excellent host properties, capable of holding high concentrations of Rhodamine 6G laser dye without aggregate formation. In this dissertation, we present the analysis of the host properties of transparent wood and show that the dye forms statistical energy traps at high concentrations of dye. By doping transparent wood with active dye and pumping it with SHGNd:YAG green laser, the optical gain within the active media can be achieved. The feedback in this optical system is occurring via scattering on fiber walls, showing behavior similar to random lasers. However, due to the semi-ordered structure and wave-guiding effect of transparent wood, the transparent wood laser is referred to as a ”quasi-random laser”. The lasing emission can be further enhanced by the introduction of an external cavity, virtually expanding the active media allowing more lasing modes to be resolved, and increasing laser power.This work demonstrates the characterization of transparent wood optical and chemical properties and develops a computational model that can be used for further investigation of light behavior in semi-ordered anisotropic media. The functionalization of transparent wood is demonstrated by the introduction of a quasi-random laser and modification of that laser is presented.
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| 9. |
- Blank, Vladimir D., et al.
(författare)
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High-pressure polymerized phases of C60
- 1998
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Ingår i: Carbon. - 0008-6223 .- 1873-3891. ; 36:4, s. 319-343
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Forskningsöversikt (övrigt vetenskapligt/konstnärligt)abstract
- Data from recent experimental studies of C60 under high pressures are collected and analyzed, concentrating on the polymerized states where covalent intermolecular bonds have been formed through treatment of molecular C60 at high pressures and temperatures at or above room temperature. We give an overview of the observed phase transformations and the structures of metastable polymeric phases, both crystalline and disordered, as analyzed under ambient conditions, and we present and discuss a pressure-temperature diagram showing which synthesis conditions result in which final phases in the pressure range up to 20 GPa (200 kbar) and at temperatures up to 2300 K. The physical properties of the various phases are discussed whenever enough data are available. The pressure-temperature stability limits for C60 and the conditions for the transformation of C60 into graphite, diamond and chaoite-type carbon are derived.
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| 10. |
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