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| 6. |
- Mercuri, E., et al.
(author)
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Safety and effectiveness of ataluren: comparison of results from the STRIDE Registry and CINRG DMD Natural History Study
- 2020
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In: Journal of Comparative Effectiveness Research. - : Becaris Publishing Limited. - 2042-6305 .- 2042-6313. ; 9:5, s. 341-360
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Journal article (peer-reviewed)abstract
- Aim: Strategic Targeting of Registries and International Database of Excellence (STRIDE) is an ongoing, multicenter registry providing real-world evidence regarding ataluren use in patients with nonsense mutation Duchenne muscular dystrophy (nmDMD). We examined the effectiveness of ataluren + standard of care (SoC) in the registry versus SoC alone in the Cooperative International Neuromuscular Research Group (CINRG) Duchenne Natural History Study (DNHS), DMD genotype-phenotype/-ataluren benefit correlations and ataluren safety. Patients & methods: Propensity score matching was performed to identify STRIDE and CINRG DNHS patients who were comparable in established disease progression predictors (registry cut-off date, 9 July 2018). Results & conclusion: Kaplan-Meier analyses demonstrated that ataluren + SoC significantly delayed age at loss of ambulation and age at worsening performance in timed function tests versus SoC alone (p <= 0.05). There were no DMD genotype-phenotype/ataluren benefit correlations. Ataluren was well tolerated. These results indicate that ataluren + SoC delays functional milestones of DMD progression in patients with nmDMD in routine clinical practice. ClinicalTrials.gov identifier: NCT02369731. ClinicalTrials.gov identifier: NCT02369731.
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| 7. |
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| 8. |
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| 9. |
- Ashizawa, T., et al.
(author)
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Consensus-based care recommendations for adults with myotonic dystrophy type 1
- 2018
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In: Neurology-Clinical Practice. - : Ovid Technologies (Wolters Kluwer Health). - 2163-0402 .- 2163-0933. ; 8:6, s. 507-520
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Research review (peer-reviewed)abstract
- Purpose of review Myotonic dystrophy type 1 (DM1) is a severe, progressive genetic disease that affects between 1 in 3,000 and 8,000 individuals globally. No evidence-based guideline exists to inform the care of these patients, and most do not have access to multidisciplinary care centers staffed by experienced professionals, creating a clinical care deficit. Recent findings The Myotonic Dystrophy Foundation (MDF) recruited 66 international clinicians experienced in DM1 patient care to develop consensus-based care recommendations. MDF created a 2-step methodology for the project using elements of the Single Text Procedure and the Nominal Group Technique. The process generated a 4-page Quick Reference Guide and a comprehensive, 55-page document that provides clinical care recommendations for 19 discrete body systems and/or care considerations. The resulting recommendations are intended to help standardize and elevate care for this patient population and reduce variability in clinical trial and study environments.
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| 10. |
- Ayeni, O. R., et al.
(author)
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Clinical and Radiographic Criteria Define "Acceptable" Surgical Correction of Hip Femoroacetabular Impingement Syndrome as Well as Postoperative Complications: An International Modified Delphi Study
- 2023
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In: Arthroscopy-the Journal of Arthroscopic and Related Surgery. - : Elsevier BV. - 0749-8063. ; 39:5, s. 1198-1210
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Journal article (peer-reviewed)abstract
- Objectives: To develop recommendations for clinical and radiographic criteria to help define the "acceptable" surgical correction of femoroacetabular impingement syndrome (FAIS) and identify/define complications postoperatively. Methods: A 3-phase modified Delphi study was conducted involving a case-based survey; a Likert/multiple choice-based survey concerning radiographic and physical examination characteristics to help define FAIS correction, as well as the prevalence and definition of potential postoperative complications; and 2 consensus meetings. Results: Of the 75 experts invited, 54 completed the Phase I survey, 50 completed the Phase II survey (72% and 67% response rate), and 50 participated in the Phase III consensus meetings. For both typical and atypical (complex) cases, there was consensus that fluoroscopy with multiple views and dynamic hip assessment should be used intraoperatively (96% and 100%, respectively). For typical FAIS cases, the Expert Panel agreed that Dunn lateral and anteroposterior radiographs were the most important radiographs to evaluate the hip postoperatively (88%, consensus). When asked about evaluating the correction of cam impingement postoperatively, 87% voted that they use subjective evaluation of the "sphericity" of the femoral head. In the case of focal and global pincer-type FAIS, there was consensus that the reduction or elimination of the crossover sign (84%) and lateral center-edge angle (91%) were important to inform the extent of the FAIS correction. There was consensus for recommending further investigation at 6 months postoperatively if hip pain had increased/plateaued (92% agreed); that additional investigation and treatment should occur between 6 and 12 months (90% agreed); and that a reoperation may be recommended at 12 months or later following this investigation period (89% agreed). Conclusions: This consensus project identified the importance of using fluoroscopy and dynamic hip assessment intraoperatively; Dunn lateral and anteroposterior view radiographs postoperatively; evaluating the "sphericity" of the femoral head for cam-type correction and the use of dynamic hip assessment; reducing/eliminating the crossover sign for focal pincertype FAIS; evaluating the lateral center-edge angle for global pincer-type FAIS; and avoiding overcorrection of pincer-type FAIS. In cases in which postoperative hip pain increased/plateaued, further investigation and treatment is warranted between 6 and 12 months, and a reoperation may be recommended at a minimum of 12 months depending on the cause of the hip pain. Clinical Relevance: Hip arthroscopy surgeons have yet to reach a firm agreement on what constitutes an "acceptable" or "good" surgery radiographically and how they can achieve desired clinical outcomes. Although this was a comprehensive effort, more study is needed to determine therapeutic thresholds that can be universally applied.
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| 12. |
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| 13. |
- Iablonskyi, D., et al.
(author)
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Slow Interatomic Coulombic Decay of Multiply Excited Neon Clusters
- 2016
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In: Physical Review Letters. - 0031-9007. ; 117:27
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Journal article (peer-reviewed)abstract
- Ne clusters (∼5000 atoms) were resonantly excited (2p→3s) by intense free electron laser (FEL) radiation at FERMI. Such multiply excited clusters can decay nonradiatively via energy exchange between at least two neighboring excited atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites of the Ne clusters were probed. We found that the relaxation of cluster surface atoms proceeds via a sequence of interatomic or intermolecular Coulombic decay (ICD) processes while ICD of bulk atoms is additionally affected by the surrounding excited medium via inelastic electron scattering. For both cases, cluster excitations relax to atomic states prior to ICD, showing that this kind of ICD is rather slow (picosecond range). Controlling the average number of excitations per cluster via the FEL intensity allows a coarse tuning of the ICD rate.
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| 14. |
- Perosa, G., et al.
(author)
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Femtosecond Polarization Shaping of Free-Electron Laser Pulses
- 2023
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In: Physical Review Letters. - 0031-9007. ; 131:4
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Journal article (peer-reviewed)abstract
- We demonstrate the generation of extreme-ultraviolet (XUV) free-electron laser (FEL) pulses with timedependent polarization. To achieve polarization modulation on a femtosecond timescale, we combine two mutually delayed counterrotating circularly polarized subpulses from two cross-polarized undulators. The polarization profile of the pulses is probed by angle-resolved photoemission and above-threshold ionization of helium; the results agree with solutions of the time-dependent Schrodinger equation. The stability limit of the scheme is mainly set by electron-beam energy fluctuations, however, at a level that will not compromise experiments in the XUV. Our results demonstrate the potential to improve the resolution and element selectivity of methods based on polarization shaping and may lead to the development of new coherent control schemes for probing and manipulating core electrons in matter.
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| 15. |
- Takanashi, T, et al.
(author)
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Time-Resolved Measurement of Interatomic Coulombic Decay Induced by Two-Photon Double Excitation of Ne2
- 2017
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In: Physical Review Letters. - 0031-9007. ; 118:3
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Journal article (peer-reviewed)abstract
- The hitherto unexplored two-photon doubly excited states [Ne∗(2p-13s)]2 were experimentally identified using the seeded, fully coherent, intense extreme ultraviolet free-electron laser FERMI. These states undergo ultrafast interatomic Coulombic decay (ICD), which predominantly produces singly ionized dimers. In order to obtain the rate of ICD, the resulting yield of Ne2+ ions was recorded as a function of delay between the extreme ultraviolet pump and UV probe laser pulses. The extracted lifetimes of the long-lived doubly excited states, 390(-130/+450) fs, and of the short-lived ones, less than 150 fs, are in good agreement with ab initio quantum mechanical calculations.
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| 16. |
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| 17. |
- Iablonskyi, D., et al.
(author)
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Interatomic Coulombic Decay Processes after Multiple Valence Excitations in Ne Clusters
- 2015
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In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 635, s. 112067-112067
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Conference paper (peer-reviewed)abstract
- We present a comprehensive analysis of autoionization processes in Ne clusters (similar to 5000 atoms) after multiple valence excitations by free electron laser radiation. The evolution from 2-body interatomic Coulombic decay (ICD) to 3-body ICD is demonstrated when changing from surface to bulk Frenkel exciton excitation. Super Coster-Kronig type 2-body ICD is observed at Wannier exciton which quenches the main ICD channel.
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| 18. |
- Jahnke, T., et al.
(author)
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Inner-Shell-Ionization-Induced Femtosecond Structural Dynamics of Water Molecules Imaged at an X-Ray Free-Electron Laser
- 2021
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In: Physical Review X. - : American Physical Society. - 2160-3308. ; 11:4
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Journal article (peer-reviewed)abstract
- The ultrafast structural dynamics of water following inner-shell ionization is a crucial issue in high-energy radiation chemistry. We have exposed isolated water molecules to a short x-ray pulse from a free-electron laser and detected momenta of all produced ions in coincidence. By combining experimental results and theoretical modeling, we can image dissociation dynamics of individual molecules in unprecedented detail. We reveal significant molecular structural dynamics in H2O2+, such as asymmetric deformation and bond-angle opening, leading to two-body or three-body fragmentation on a timescale of a few femtoseconds. We thus reconstruct several snapshots of structural dynamics at different time intervals, which highlight dynamical patterns that are relevant as initiating steps of subsequent radiation-damage processes.
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| 19. |
- Makos, I., et al.
(author)
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Attosecond photoelectron spectroscopy using high-harmonic generation and seeded free-electron lasers
- 2023
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In: 2023 Photonics North, PN 2023. - 9798350326734
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Conference paper (peer-reviewed)abstract
- In this work, we use attosecond time-resolved techniques to investigate photoionization dynamics on its natural timescale, employing both high harmonic generation and seeded free-electron lasers to generate extreme ultraviolet attosecond pulse trains for our studies. With the former approach, we examine the role of nuclear motion in molecular photoionization dynamics, while with the latter we introduce a novel attosecond timing tool for single-shot characterization of the relative phase between the XUV and the infrared field.
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| 20. |
- Maroju, P. K., et al.
(author)
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Analysis of two-color photoelectron spectroscopy for attosecond metrology at seeded free-electron lasers
- 2021
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In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 23:4
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Journal article (peer-reviewed)abstract
- The generation of attosecond pulse trains at free-electron lasers opens new opportunities in ultrafast science, as it gives access, for the first time, to reproducible, programmable, extreme ultraviolet (XUV) waveforms with high intensity. In this work, we present a detailed analysis of the theoretical model underlying the temporal characterization of the attosecond pulse trains recently generated at the free-electron laser FERMI. In particular, the validity of the approximations used for the correlated analysis of the photoelectron spectra generated in the two-color photoionization experiments are thoroughly discussed. The ranges of validity of the assumptions, in connection with the main experimental parameters, are derived.
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| 21. |
- Maroju, Praveen Kumar, et al.
(author)
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Attosecond coherent control of electronic wave packets in two-colour photoionization using a novel timing tool for seeded free-electron laser
- 2023
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In: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 17, s. 200-207
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Journal article (peer-reviewed)abstract
- In ultrafast spectroscopy, the temporal resolution of time-resolved experiments depends on the duration of the pump and probe pulses, and on the control and characterization of their relative synchronization. Free-electron lasers operating in the extreme ultraviolet and X-ray spectral regions deliver pulses with femtosecond and attosecond duration in a broad array of pump-probe configurations to study a wide range of physical processes. However, this flexibility, together with the large dimensions and high complexity of the experimental set-ups, limits control of the temporal delay to the femtosecond domain, thus precluding a time resolution below the optical cycle. Here we demonstrate a novel single-shot technique able to determine the relative synchronization between an attosecond pulse train-generated by a seeded free-electron laser-and the optical oscillations of a near-infrared field, with a resolution of one atomic unit (24 as). Using this attosecond timing tool, we report the first example of attosecond coherent control of photoionization in a two-colour field by manipulating the phase of high-order near-infrared transitions.
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| 22. |
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| 23. |
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| 24. |
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| 25. |
- Austin, CC, et al.
(author)
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Fostering global data sharing: highlighting the recommendations of the Research Data Alliance COVID-19 working group
- 2020
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In: Wellcome open research. - : F1000 Research Ltd. - 2398-502X. ; 5, s. 267-
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Journal article (peer-reviewed)abstract
- The systemic challenges of the COVID-19 pandemic require cross-disciplinary collaboration in a global and timely fashion. Such collaboration needs open research practices and the sharing of research outputs, such as data and code, thereby facilitating research and research reproducibility and timely collaboration beyond borders. The Research Data Alliance COVID-19 Working Group recently published a set of recommendations and guidelines on data sharing and related best practices for COVID-19 research. These guidelines include recommendations for clinicians, researchers, policy- and decision-makers, funders, publishers, public health experts, disaster preparedness and response experts, infrastructure providers from the perspective of different domains (Clinical Medicine, Omics, Epidemiology, Social Sciences, Community Participation, Indigenous Peoples, Research Software, Legal and Ethical Considerations), and other potential users. These guidelines include recommendations for researchers, policymakers, funders, publishers and infrastructure providers from the perspective of different domains (Clinical Medicine, Omics, Epidemiology, Social Sciences, Community Participation, Indigenous Peoples, Research Software, Legal and Ethical Considerations). Several overarching themes have emerged from this document such as the need to balance the creation of data adherent to FAIR principles (findable, accessible, interoperable and reusable), with the need for quick data release; the use of trustworthy research data repositories; the use of well-annotated data with meaningful metadata; and practices of documenting methods and software. The resulting document marks an unprecedented cross-disciplinary, cross-sectoral, and cross-jurisdictional effort authored by over 160 experts from around the globe. This letter summarises key points of the Recommendations and Guidelines, highlights the relevant findings, shines a spotlight on the process, and suggests how these developments can be leveraged by the wider scientific community.
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| 26. |
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| 27. |
- Gryzlova, E. V., et al.
(author)
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Influence of an atomic resonance on the coherent control of the photoionization process
- 2022
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In: Physical Review Research. - 2643-1564. ; 4:3
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Journal article (peer-reviewed)abstract
- In coherent control schemes, pathways connecting an initial and a final state can be independently controlled by manipulating the complex amplitudes of their transition matrix elements. For paths characterized by the absorption of multiple photons, these quantities depend on the magnitude and phase between the intermediate steps, and are expected to be strongly affected by the presence of resonances. We investigate the coherent control of the photoemission process in neon using a phase-controlled two-color extreme ultraviolet pulse with frequency in proximity of an excited energy state. Using helium as a reference, we show that the presence of such a resonance in neon modifies the amplitude and phase of the asymmetric emission of photoelectrons. Theoretical simulations based on perturbation theory are in fair agreement with the experimental observations.
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| 28. |
- Marconi, A, et al.
(author)
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ERRATUM
- 2016
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In: Psychology, health & medicine. - 1465-3966. ; 21:6, s. VII-VII
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Journal article (peer-reviewed)
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| 29. |
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| 30. |
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| 31. |
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| 32. |
- Uhl, D., et al.
(author)
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Improved stabilization scheme for extreme ultraviolet quantum interference experiments
- 2022
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In: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 55
-
Journal article (peer-reviewed)abstract
- Interferometric pump-probe experiments in the extreme ultraviolet (XUV) domain are experimentally very challenging due to the high phase stability required between the XUV pulses. Recently, an efficient phase stabilization scheme was introduced for seeded XUV free electron lasers (FELs) combining shot-to-shot phase modulation with lock-in detection [A. Wituschek et al., Nat Commun 11, 1 (2020)]. This method stabilized the seed laser beampath on the fundamental ultraviolet wavelength to a high degree. Here, we extend this scheme including the stabilization of the XUV beampath, incorporating phase fluctuations from the FEL high gain harmonic generation process. Our analysis reveals a clear signal improvement with the new method compared to the previous stabilization scheme.
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| 33. |
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| 34. |
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| 35. |
- Ertel, D., et al.
(author)
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Ultrastable, high-repetition-rate attosecond beamline for time-resolved XUV-IR coincidence spectroscopy
- 2023
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In: Review of Scientific Instruments. - 0034-6748. ; 94:7
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Journal article (peer-reviewed)abstract
- The implementation of attosecond photoelectron-photoion coincidence spectroscopy for the investigation of atomic and molecular dynamics calls for a high-repetition-rate driving source combined with experimental setups characterized by excellent stability for data acquisition over time intervals ranging from a few hours up to a few days. This requirement is crucial for the investigation of processes characterized by low cross sections and for the characterization of fully differential photoelectron(s) and photoion(s) angular and energy distributions. We demonstrate that the implementation of industrial-grade lasers, combined with a careful design of the delay line implemented in the pump-probe setup, allows one to reach ultrastable experimental conditions leading to an error in the estimation of the time delays of only 12 as over an acquisition time of 6.5 h. This result opens up new possibilities for the investigation of attosecond dynamics in simple quantum systems.
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| 36. |
- Fushitani, Mizuho, et al.
(author)
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Time-resolved photoelectron imaging of complex resonances in molecular nitrogen
- 2021
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In: The Journal of chemical physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 154:14
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Journal article (peer-reviewed)abstract
- We have used the FERMI free-electron laser to perform time-resolved photoelectron imaging experiments on a complex group of resonances near 15.38 eV in the absorption spectrum of molecular nitrogen, N2, under jet-cooled conditions. The new data complement and extend the earlier work of Fushitani et al. [Opt. Express 27, 19702–19711 (2019)], who recorded time-resolved photoelectron spectra for this same group of resonances. Time-dependent oscillations are observed in both the photoelectron yields and the photoelectron angular distributions, providing insight into the interactions among the resonant intermediate states. In addition, for most states, we observe an exponential decay of the photoelectron yield that depends on the ionic final state. This observation can be rationalized by the different lifetimes for the intermediate states contributing to a particular ionization channel. Although there are nine resonances within the group, we show that by detecting individual photoelectron final states and their angular dependence, we can identify and differentiate quantum pathways within this complex system.
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| 37. |
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| 38. |
- Godshaw, B. M., et al.
(author)
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Posterior tibial plateau impaction fractures are not associated with increased knee instability: a quantitative pivot shift analysis
- 2023
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In: Knee Surgery Sports Traumatology Arthroscopy. - : Springer Science and Business Media LLC. - 0942-2056 .- 1433-7347.
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Journal article (peer-reviewed)abstract
- Purpose This study aimed to evaluate posterolateral tibial plateau impaction fractures and how they contribute to rotatory knee laxity using quantitative pivot shift analysis. It was hypothesised that neither the presence of nor the degree of involvement of the plateau would affect rotatory knee laxity in the ACL-deficient knee. Methods A retrospective review of prospectively collected data on 284 patients with complete anterior cruciate ligament (ACL) injuries was conducted. Posterolateral tibial plateau impaction fractures were identified on preoperative MRI. The patients were divided into two cohorts: "fractures" or "no fractures". The cohort with fractures was further categorised based on fracture morphology: "extra-articular", "articular-impaction", or "displaced-articular fragment". All data were collected during examination under anaesthesia performed immediately prior to ACL reconstruction. This included a standard pivot shift test graded by the examiner and quantitative data including anterior tibial translation (mm) via Rolimeter, quantitative pivot shift (QPS) examination ( mm) via PIVOT tablet technology, and acceleration (m/sec(2)) during the pivot shift test via accelerometer. Quantitative examinations were compared with the contralateral knee. Results There were 112 patients with posterolateral tibial plateau impaction fractures (112/284, 39%). Of these, 71/112 (63%) were "extra-articular", 28/112 (25%) "articular-impaction", and 13/112 ( 12%) "displaced-articular". Regarding the two groups with or without fractures, there was no difference in subjective pivot shift (2 +/- 0 vs 2 +/- 0, respectively, n.s.), QPS (2.4 +/- 1.6 mm vs 2.7 +/- 2.2 mm, respectively, n.s.), anterior tibial translation measurements (6 +/- 3 mm vs 5 +/- 3 mm, respectively, n.s.), or acceleration of the knee during the pivot (1.7 +/- 2.3 m/s(2) vs 1.8 +/- 3.1 m/s(2), respectively, n.s.). When the fractures were further subdivided, subgroup analysis revealed no significant differences noted in any of the measured examinations between the fracture subtypes. Conclusion This study showed that the posterolateral tibial plateau impaction fractures are commonly encountered in the setting of ACL tears; however, contrary to previous reports, they do not significantly increase rotatory knee laxity. This suggests that this type of concomitant injury may not need to be addressed at the time of ACL reconstruction.
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| 39. |
- Gonzalez-Beltran, AN, et al.
(author)
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Community standards for open cell migration data
- 2020
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In: GigaScience. - : Oxford University Press (OUP). - 2047-217X. ; 9:5
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Journal article (peer-reviewed)abstract
- Cell migration research has become a high-content field. However, the quantitative information encapsulated in these complex and high-dimensional datasets is not fully exploited owing to the diversity of experimental protocols and non-standardized output formats. In addition, typically the datasets are not open for reuse. Making the data open and Findable, Accessible, Interoperable, and Reusable (FAIR) will enable meta-analysis, data integration, and data mining. Standardized data formats and controlled vocabularies are essential for building a suitable infrastructure for that purpose but are not available in the cell migration domain. We here present standardization efforts by the Cell Migration Standardisation Organisation (CMSO), an open community-driven organization to facilitate the development of standards for cell migration data. This work will foster the development of improved algorithms and tools and enable secondary analysis of public datasets, ultimately unlocking new knowledge of the complex biological process of cell migration.
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| 40. |
- Grilli, Simonetta, et al.
(author)
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Double-face and submicron two-dimensional domain patterning in congruent lithium niobate
- 2006
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In: IEEE photonics technology letters. - 1041-1135. ; 18, s. 541-
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Journal article (peer-reviewed)abstract
- We report on the simultaneous fabrication of two-dimensional submicron engineered domain patterns on both crystal faces, in congruent lithium niobate. The fabrication technique is based on interference photolithography, which allows short pitch over large areas, followed by electric field poling performed in overpoling regime. Experimental results for different domain pattern geometries, on the two crystal faces, are reported. These structures could be useful for short-wavelength frequency conversion and Bragg gratings applications. The moire effect is used in the lithographic process to fabricate more complex structures which could find application in photonic bandgap devices.
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| 41. |
- Grilli, Simonetta, et al.
(author)
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Two-dimensional mapping of electro-optic phase retardation in lithium niobate crystals by digital holography
- 2005
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In: Optics letters. - 0146-9592. ; 30:13, s. 1671-1673
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Journal article (peer-reviewed)abstract
- We demonstrate accurate two-dimensional mapping of the phase retardation induced by the electro-optic effect in lithium niobate crystals. Off-axis digital holography is used to investigate congruent z-cut crystals. The spatially resolved optical path difference is interferometrically measured while a linearly rising voltage ramp is applied to the crystal. This procedure provides information on the uniformity of crystals' electro-optic properties and offers the ability to detect the presence of defects that is of fundamental importance for reliable processing of photonic devices.
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| 42. |
- Guillemin, R., et al.
(author)
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Isotope effects in dynamics of water isotopologues induced by core ionization at an x-ray free-electron laser
- 2023
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In: STRUCTURAL DYNAMICS-US. - 2329-7778. ; 10:5
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Journal article (peer-reviewed)abstract
- Dynamical response of water exposed to x-rays is of utmost importance in a wealth of science areas. We exposed isolated water isotopologues to short x-ray pulses from a free-electron laser and detected momenta of all produced ions in coincidence. By combining experimental results and theoretical modeling, we identify significant structural dynamics with characteristic isotope effects in H2O2+, D2O2+, and HDO2+, such as asymmetric bond elongation and bond-angle opening, leading to two-body or three-body fragmentation on a timescale of a few femtoseconds. A method to disentangle the sequences of events taking place upon the consecutive absorption of two x-ray photons is described. The obtained deep look into structural properties and dynamics of dissociating water isotopologues provides essential insights into the underlying mechanisms.
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| 43. |
- Kelkensberg, F., et al.
(author)
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Molecular Dissociative Ionization and Wave-Packet Dynamics Studied Using Two-Color XUV and IR Pump-Probe Spectroscopy
- 2009
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In: Physical Review Letters. - 1079-7114. ; 103:12
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Journal article (peer-reviewed)abstract
- We present a combined theoretical and experimental study of ultrafast wave-packet dynamics in the dissociative ionization of H-2 molecules as a result of irradiation with an extreme-ultraviolet (XUV) pulse followed by an infrared (IR) pulse. In experiments where the duration of both the XUV and IR pulses are shorter than the vibrational period of H-2+, dephasing and rephasing of the vibrational wave packet that is formed in H-2+ upon ionization of the neutral molecule by the XUV pulse is observed. In experiments where the duration of the IR pulse exceeds the vibrational period of H-2+ (15 fs), a pronounced dependence of the H+ kinetic energy distribution on XUV-IR delay is observed that can be explained in terms of the adiabatic propagation of the H-2+ wave packet on field-dressed potential energy curves.
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| 44. |
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| 45. |
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| 46. |
- Klünder, Kathrin, et al.
(author)
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Reconstruction of attosecond electron wave packets using quantum state holography
- 2013
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In: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 88:3
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Journal article (peer-reviewed)abstract
- We present a method for performing quantum state holography, with which we completely characterize the amplitude and phase of an attosecond electron wave packet. Our approach is an extension of a recent publication [J. Mauritsson et al., Phys. Rev. Lett. 105, 053001 (2010)] in which we demonstrated experimentally that the energies and amplitudes of an attosecond electron wave packet can be characterized using attosecond electron interferometry. Here we show theoretically that attosecond electron interferometry can be extended to retrieve the phases of all the states that make up the wave packet. We demonstrate the feasibility of our method by analyzing a wave packet created by a shake-up process. We show that our method can successfully retrieve arbitrary phases and/or lifetimes added to the component eigenstates.
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| 47. |
- Kumar Maroju, Praveen, et al.
(author)
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Attosecond pulse shaping using a seeded free-electron laser
- 2020
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 578, s. 386-391
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Journal article (peer-reviewed)abstract
- Attosecond pulses are central to the investigation of valence- and core-electron dynamics on their natural timescales. The reproducible generation and characterization of attosecond waveforms has been demonstrated so far only through the process of high-order harmonic generation. Several methods for shaping attosecond waveforms have been proposed, including the use of metallic filters, multilayer mirrors and manipulation of the driving field. However, none of these approaches allows the flexible manipulation of the temporal characteristics of the attosecond waveforms, and they suffer from the low conversion efficiency of the high-order harmonic generation process. Free-electron lasers, by contrast, deliver femtosecond, extreme-ultraviolet and X-ray pulses with energies ranging from tens of microjoules to a few millijoules. Recent experiments have shown that they can generate subfemtosecond spikes, but with temporal characteristics that change shot-to-shot. Here we report reproducible generation of high-energy (microjoule level) attosecond waveforms using a seeded free-electron laser. We demonstrate amplitude and phase manipulation of the harmonic components of an attosecond pulse train in combination with an approach for its temporal reconstruction. The results presented here open the way to performing attosecond time-resolved experiments with free-electron lasers.
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| 48. |
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| 49. |
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| 50. |
- Maroju, Praveen K., et al.
(author)
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A Novel Attosecond Timing Tool for Free-Electron Laser Experiment
- 2020
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In: High Intensity Lasers and High Field Phenomena 2020. - 9781943580736
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Conference paper (peer-reviewed)abstract
- We demonstrate a novel timing tool for Free-Electron Lasers to determine the delay between an attosecond pulse train and infrared pulse with sub-optical-cycle resolu-. tion.
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