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- Cespedes, PF, et al.
(författare)
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T-cell trans-synaptic vesicles are distinct and carry greater effector content than constitutive extracellular vesicles
- 2022
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1, s. 3460-
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Tidskriftsartikel (refereegranskat)abstract
- The immunological synapse is a molecular hub that facilitates the delivery of three activation signals, namely antigen, costimulation/corepression and cytokines, from antigen-presenting cells (APC) to T cells. T cells release a fourth class of signaling entities, trans-synaptic vesicles (tSV), to mediate bidirectional communication. Here we present bead-supported lipid bilayers (BSLB) as versatile synthetic APCs to capture, characterize and advance the understanding of tSV biogenesis. Specifically, the integration of juxtacrine signals, such as CD40 and antigen, results in the adaptive tailoring and release of tSV, which differ in size, yields and immune receptor cargo compared with steadily released extracellular vesicles (EVs). Focusing on CD40L+tSV as model effectors, we show that PD-L1 trans-presentation together with TSG101, ADAM10 and CD81 are key in determining CD40L vesicular release. Lastly, we find greater RNA-binding protein and microRNA content in tSV compared with EVs, supporting the specialized role of tSV as intercellular messengers.
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| 4. |
- Chao, Y, et al.
(författare)
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Reactions and luminescence in passivated Si nanocrystallites induced by vacuum ultraviolet and soft-x-ray photons
- 2005
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Ingår i: Applied Physics Reviews. - : AIP Publishing. - 1931-9401. ; 98:4
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Tidskriftsartikel (refereegranskat)abstract
- Alkyl-modified silicon nanocrystallites are efficient fluorophores which are of interest for fundamental spectroscopic studies and as luminescent probes in biology because of their stability in aqueous media. In this work we have investigated these particles using scanning tunneling microscopy, synchrotron-radiation excited photoemission, and x-ray excited optical luminescence (XEOL). During the course of illumination with 145-eV photons we have monitored the evolution of the Si2p core level and, in samples which have suffered prolonged atmospheric exposure, observed in real time the growth of an extra Si2p component attributed to in situ photoinduced oxidation of the Si nanocrystallites. XEOL reveals that two emission bands are active upon soft-x-ray photon excitation and that photoluminescence intensity decreases with photon exposure, which is attributed to charge trapping within the film.
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| 6. |
- Siller, L., et al.
(författare)
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Core and valence exciton formation in x-ray absorption, x-ray emission and x-ray excited optical luminescence from passivated Si nanocrystals at the Si L-2,L-3 edge
- 2009
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Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 1361-648X .- 0953-8984. ; 21:9
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Tidskriftsartikel (refereegranskat)abstract
- Resonant inelastic x-ray scattering (RIXS), x-ray absorption spectroscopy and x-ray excited optical luminescence (XEOL) have been used to measure element specific filled and empty electronic states over the Si L-2,L-3 edge of passivated Si nanocrystals of narrow size distribution ( diameter 2.2 +/- 0.4 nm). These techniques have been employed to directly measure absorption and luminescence specific to the local Si nanocrystal core. Profound changes occur in the absorption spectrum of the nanocrystals compared with bulk Si, and new features are observed in the nanocrystal RIXS. Clear signatures of core and valence band exciton formation, promoted by the spatial confinement of electrons and holes within the nanocrystals, are observed, together with band narrowing due to quantum confinement. XEOL at 12 K shows an extremely sharp feature at the threshold of orange luminescence (i.e., at similar to 1.56 eV ( 792 nm)) which we attribute to recombination of valence excitons, providing a lower limit to the nanocrystal band gap.
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