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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Madl, Christopher M., et al.
(författare)
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Maintenance of neural progenitor cell stemness in 3D hydrogels requires matrix remodelling
- 2017
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-4660 .- 1476-1122. ; 16:12, s. 1233-1242
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Tidskriftsartikel (refereegranskat)abstract
- Neural progenitor cell (NPC) culture within three-dimensional (3D) hydrogels is an attractive strategy for expanding a therapeutically relevant number of stem cells. However, relatively little is known about how 3D material properties such as stiffness and degradability affect the maintenance of NPC stemness in the absence of differentiation factors. Over a physiologically relevant range of stiffness from â 1/40.5 to 50 kPa, stemness maintenance did not correlate with initial hydrogel stiffness. In contrast, hydrogel degradation was both correlated with, and necessary for, maintenance of NPC stemness. This requirement for degradation was independent of cytoskeletal tension generation and presentation of engineered adhesive ligands, instead relying on matrix remodelling to facilitate cadherin-mediated cell-cell contact and promote ?-catenin signalling. In two additional hydrogel systems, permitting NPC-mediated matrix remodelling proved to be a generalizable strategy for stemness maintenance in 3D. Our findings have identified matrix remodelling, in the absence of cytoskeletal tension generation, as a previously unknown strategy to maintain stemness in 3D.
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| 3. |
- Alshaykh, Mohammed S., et al.
(författare)
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Optical dual-comb Vernier division of an octave-spanning Kerr microcomb
- 2021
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Ingår i: 2021 Conference on Lasers and Electro-Optics, CLEO 2021 - Proceedings.
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Konferensbidrag (refereegranskat)abstract
- We measure the repetition rate of a 900 GHz octave-spanning soliton microcomb based on Vernier dual-comb frequency division implemented with two silicon nitride microresonator combs fabricated on the same wafer.
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| 4. |
- O'Malley, Nathan P., et al.
(författare)
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RF Stabilization of Vernier Dual-microcombs
- 2023
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Ingår i: 2023 Conference on Lasers and Electro-Optics, CLEO 2023.
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Konferensbidrag (refereegranskat)abstract
- Leveraging the Vernier dual-comb method, we self-reference a THz octave-spanning microcomb with fCEO ~100 GHz - normally too high for typical detection equipment - and translate the stability of an RF reference to optical frequencies.
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| 5. |
- O'Malley, Nathan P., et al.
(författare)
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Vernier Frequency Combs for Stabilization of RF/Optical Links
- 2022
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Ingår i: Optics InfoBase Conference Papers. - 9781957171050
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Konferensbidrag (refereegranskat)abstract
- We utilize the Vernier effect to partially stabilize a pair of high repetition rate, octave-spanning Kerr solitons in silicon nitride microrings fabricated on the same wafer.
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| 6. |
- O'Malley, Nathan P., et al.
(författare)
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Vernier Microcombs for Future Miniature Yb + Clocks
- 2023
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Ingår i: 2023 IEEE Photonics Conference, IPC 2023 - Proceedings.
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Konferensbidrag (refereegranskat)abstract
- We demonstrate an architecture for dualmicrocomb-based readout of an optical clock. Microcombs frequency-divide a compact narrow-linewidth laser, capable of being frequency-doubled to within a few GHz of a 171Yb+ clock transition, to an RF output.
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| 7. |
- Toftegaard, R., et al.
(författare)
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Metal nanoparticle-enhanced radiative transitions: Giving singlet oxygen emission a boost
- 2011
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Ingår i: Pure and Applied Chemistry. - : Walter de Gruyter GmbH. - 1365-3075 .- 0033-4545. ; 83:4, s. 885-898
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Tidskriftsartikel (refereegranskat)abstract
- The fabrication and use of metal nanoparticles to influence electronic transitions in a given molecule is of growing interest; there is much to be gained by developing and exploiting methods to enhance weak optical signals. Singlet molecular oxygen, O-2(a(1)Delta(g)), which is an important intermediate in many oxidation reactions, particularly in biological systems, is ideally monitored by the 1275-nm O-2(a(1)Delta(g)) -> O-2(X-3 Sigma(-)(g)) phosphorescent transition. Unfortunately, the latter is highly forbidden and, as such, often presents a severe limitation in the application of this optical probe. In this paper, we describe how this weak phosphorescent transition can be enhanced by using localized surface plasmons (LSPs) from specially engineered gold nanostructures. In an attempt to elucidate the mechanism of this process, data were recorded from samples in which we decoupled the component of the plasmon resonance that absorbs incident light from the component that scatters incident light. We find that the latter appears to be the feature of significance in the process through which singlet oxygen phosphorescence is enhanced. In this work, we also illustrate how the singlet oxygen system provides an ideal model for a general study of metal-enhanced radiative rate constants.
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| 8. |
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| 9. |
- Wiedorn, Max O., et al.
(författare)
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Megahertz serial crystallography
- 2018
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The new European X-ray Free-Electron Laser is the first X-ray free-electron laser capable of delivering X-ray pulses with a megahertz inter-pulse spacing, more than four orders of magnitude higher than previously possible. However, to date, it has been unclear whether it would indeed be possible to measure high-quality diffraction data at megahertz pulse repetition rates. Here, we show that high-quality structures can indeed be obtained using currently available operating conditions at the European XFEL. We present two complete data sets, one from the well-known model system lysozyme and the other from a so far unknown complex of a beta-lactamase from K. pneumoniae involved in antibiotic resistance. This result opens up megahertz serial femtosecond crystallography (SFX) as a tool for reliable structure determination, substrate screening and the efficient measurement of the evolution and dynamics of molecular structures using megahertz repetition rate pulses available at this new class of X-ray laser source.
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| 10. |
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