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- Baker, C. J., et al.
(författare)
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Sympathetic cooling of positrons to cryogenic temperatures for antihydrogen production
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The positron, the antiparticle of the electron, predicted by Dirac in 1931 and discovered by Anderson in 1933, plays a key role in many scientific and everyday endeavours. Notably, the positron is a constituent of antihydrogen, the only long-lived neutral antimatter bound state that can currently be synthesized at low energy, presenting a prominent system for testing fundamental symmetries with high precision. Here, we report on the use of laser cooled Be+ ions to sympathetically cool a large and dense plasma of positrons to directly measured temperatures below 7 K in a Penning trap for antihydrogen synthesis. This will likely herald a significant increase in the amount of antihydrogen available for experimentation, thus facilitating further improvements in studies of fundamental symmetries. Positrons are key to the production of cold antihydrogen. Here the authors report the sympathetic cooling of positrons by interacting them with laser-cooled Be+ ions resulting in a three-fold reduction of the temperature of positrons for antihydrogen synthesis.
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- Mistri, Mourmita, et al.
(författare)
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Tribomechanical insight into carbide-laden hybrid suspension-powder plasma-sprayed Tribaloy T400 composite coatings
- 2020
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 396
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Tidskriftsartikel (refereegranskat)abstract
- Tribaloy T400 (CoCrMoSi) caters to heavy-duty industrial tribological demands, but exhibits low fracture toughness with compromised resistance to crack propagation owing to the disparity in % Laves phases. In response to this limitation, hybrid suspension-powder plasma-sprayed novel Cr3C2 (d50 of 3.8 ÎŒm)/TiC (d50 of 2.2 ÎŒm) reinforced T400 (average powder size of 10–45 ÎŒm) coatings are deposited on grit-blasted SSAB Domex®350 LA steel. Continuous, adherent and co-existing lamellar T400-carbide coatings of 100 ÎŒm thickness were revealed in microstructure analysis. Intermetallic CoMoSi/Co3Mo2Si Laves and eutectic Co7Mo6/Co2Mo7 phases in T400 in addition to Cr3C2/TiC characteristic phases are confirmed via X-ray diffraction study. T400-Cr3C2 and T400-TiC have exhibited enhancement in elastic modulus (E) by 39%, and 36%, Vickers hardness (Hv) by 68%, and 82.5%; which consequently elucidates the augmentation in plasticity index (re) by 15.7% and 26.7%, and the drop in maximum displacement amplitude (hmax) by 14.9% and 19.8%, respectively, in T400-Cr3C2 and T400-TiC with reference to T400 (E of 135.2 GPa, Hv of 6.3 GPa, re = 0.318, and hmax = 1947 nm). A subsequent surmised fretting Hertzian contact diameter in T400-Cr3C2 ( 95.43 ÎŒm)/T400-TiC ( 96.1 ÎŒm) evaluated against T400 ( 106.9 ÎŒm) from optical profilometry indicates an improved damage tolerance. A contact area-based wear model, proposed herein to assess wear on a rough surface, further justifies the wear characteristics. Furthermore, synergistic L929 cell viability is recorded in T400-Cr3C2 (by 46%) and T400-TiC (by 30%) when compared with the control (+ve) disk. To conclude, suspension-powder plasma-sprayed T400-Cr3C2/T400-TiC composite coatings allude potential application in wear-resistant articulating surfaces by eliciting significantly enhanced micro-hardness through refined microstructure retention, improved fretting wear resistance by forming protective tribofilm, and augmented cellular response. © 2020 Elsevier B.V.
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- Mistrik, M, et al.
(författare)
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Microthermal-induced subcellular-targeted protein damage in cells on plasmonic nanosilver-modified surfaces evokes a two-phase HSP-p97/VCP response
- 2021
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1, s. 713-
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Tidskriftsartikel (refereegranskat)abstract
- Despite proteotoxic stress and heat shock being implicated in diverse pathologies, currently no methodology to inflict defined, subcellular thermal damage exists. Here, we present such a single-cell method compatible with laser-scanning microscopes, adopting the plasmon resonance principle. Dose-defined heat causes protein damage in subcellular compartments, rapid heat-shock chaperone recruitment, and ensuing engagement of the ubiquitin–proteasome system, providing unprecedented insights into the spatiotemporal response to thermal damage relevant for degenerative diseases, with broad applicability in biomedicine. Using this versatile method, we discover that HSP70 chaperone and its interactors are recruited to sites of thermally damaged proteins within seconds, and we report here mechanistically important determinants of such HSP70 recruitment. Finally, we demonstrate a so-far unsuspected involvement of p97(VCP) translocase in the processing of heat-damaged proteins. Overall, we report an approach to inflict targeted thermal protein damage and its application to elucidate cellular stress-response pathways that are emerging as promising therapeutic targets.
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