| 1. |
- Coudert-Alteirac, Hélène, et al.
(author)
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Micro-focusing of broadband high-order harmonic radiation by a double toroidal mirror
- 2017
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In: Applied Sciences (Switzerland). - : MDPI AG. - 2076-3417. ; 7:11
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Journal article (peer-reviewed)abstract
- We present an optical system based on two toroidal mirrors in aWolter configuration to focus broadband extreme ultraviolet (XUV) radiation. Optimization of the focusing optics alignment is carried out with the aid of an XUV wavefront sensor. Back-propagation of the optimized wavefront to the focus yields a focal spot of 3.6 × 4.0 μm2 full width at half maximum, which is consistent with ray-tracing simulations that predict a minimum size of 3.0 × 3.2 μm2. This work is important for optimizing the intensity of focused high-order harmonics in order to reach the nonlinear interaction regime.
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| 2. |
- Dacasa, Hugo, et al.
(author)
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Single-shot extreme-ultraviolet wavefront measurements of high-order harmonics
- 2019
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In: Optics Express. - 1094-4087. ; 27:3, s. 2656-2670
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Journal article (peer-reviewed)abstract
- We perform wavefront measurements of high-order harmonics using an extreme-ultraviolet (XUV) Hartmann sensor and study how their spatial properties vary with different generation parameters, such as pressure in the nonlinear medium, fundamental pulse energy and duration as well as beam size. In some conditions, excellent wavefront quality (up to 휆/11) was obtained. The high throughput of the intense XUV beamline at the Lund Laser Centre allows us to perform single-shot measurements of both the full harmonic beam generated in argon and individual harmonics selected by multilayer mirrors. We theoretically analyze the relationship between the spatial properties of the fundamental and those of the generated high-order harmonics, thus gaining insight into the fundamental mechanisms involved in high-order harmonic generation (HHG).
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| 3. |
- Perrot, Nicolas, et al.
(author)
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Genetic and In Vitro Inhibition of PCSK9 and Calcific Aortic Valve Stenosis
- 2020
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In: JACC: Basic to Translational Science. - : Elsevier BV. - 2452-302X. ; 5:7, s. 649-661
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Journal article (peer-reviewed)abstract
- The authors investigated whether PCSK9 inhibition could represent a therapeutic strategy in calcific aortic valve stenosis (CAVS). A meta-analysis of 10 studies was performed to determine the impact of the PCSK9 R46L variant on CAVS, and the authors found that CAVS was less prevalent in carriers of this variant (odds ratio: 0.80 [95% confidence interval: 0.70 to 0.91]; p = 0.0011) compared with noncarriers. PCSK9 expression was higher in the aortic valves of patients CAVS compared with control patients. In human valve interstitials cells submitted to a pro-osteogenic medium, PCSK9 levels increased and a PCSK9 neutralizing antibody significantly reduced calcium accumulation.
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| 4. |
- Perrot, Nicolas, et al.
(author)
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Lipoprotein-associated phospholipase A2 activity, genetics and calcific aortic valve stenosis in humans
- 2020
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In: Heart. - : BMJ. - 1355-6037 .- 1468-201X. ; 106:18, s. 1407-1412
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Journal article (peer-reviewed)abstract
- Background: Lipoprotein-associated phospholipase A2 (Lp-PLA2) activity has been shown to predict calcific aortic valve stenosis (CAVS) outcomes. Our objective was to test the association between plasma Lp-PLA2 activity and genetically elevated Lp-PLA2 mass/activity with CAVS in humans. Methods and results: Lp-PLA2 activity was measured in 890 patients undergoing cardiac surgery, including 476 patients undergoing aortic valve replacement for CAVS and 414 control patients undergoing coronary artery bypass grafting. After multivariable adjustment, Lp-PLA2 activity was positively associated with the presence of CAVS (OR=1.21 (95% CI 1.04 to 1.41) per SD increment). We selected four single nucleotide polymorphisms (SNPs) at the PLA2G7 locus associated with either Lp-PLA2 mass or activity (rs7756935, rs1421368, rs1805017 and rs4498351). Genetic association studies were performed in eight cohorts: Quebec-CAVS (1009 cases/1017 controls), UK Biobank (1350 cases/349 043 controls), European Prospective Investigation into Cancer and Nutrition-Norfolk (504 cases/20 307 controls), Genetic Epidemiology Research on Aging (3469 cases/51 723 controls), Malmö Diet and Cancer Study (682 cases/5963 controls) and three French cohorts (3123 cases/6532 controls), totalling 10 137 CAVS cases and 434 585 controls. A fixed-effect meta-analysis using the inverse-variance weighted method revealed that none of the four SNPs was associated with CAVS (OR=0.99 (95% CI 0.96 to 1.02, p=0.55) for rs7756935, 0.97 (95% CI 0.93 to 1.01, p=0.11) for rs1421368, 1.00 (95% CI 1.00 to 1.01, p=0.29) for rs1805017, and 1.00 (95% CI 0.97 to 1.04, p=0.87) for rs4498351). Conclusions: Higher Lp-PLA2 activity is significantly associated with the presence of CAVS and might represent a biomarker of CAVS in patients with heart disease. Results of our genetic association study suggest that Lp-PLA2 is however unlikely to represent a causal risk factor or therapeutic target for CAVS.
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| 5. |
- Vodungbo, Boris, et al.
(author)
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Indirect excitation of ultrafast demagnetization.
- 2016
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Journal article (peer-reviewed)abstract
- Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a negligible number of IR photons penetrate the aluminum layer. In comparison with an uncapped cobalt/palladium reference film, the initial demagnetization of the capped film occurs with a delayed onset and at a slower rate. Both observations are qualitatively in line with energy transport from the aluminum layer into the underlying magnetic film by the excited, hot electrons of the aluminum film. Our data thus confirm recent theoretical predictions.
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| 6. |
- Wodzinski, Thomas, et al.
(author)
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High-harmonic generation wave front dependence on a driving infrared wave front
- 2020
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In: Applied Optics. - : Optical Society of America. - 1559-128X .- 2155-3165. ; 59:5, s. 1363-1370
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Journal article (peer-reviewed)abstract
- With high-harmonic generation (HHG), spatially and temporally coherent XUV to soft x-ray (100 nm to 10 nm) table-top sources can be realized by focusing a driving infrared (IR) laser on a gas target. For applications such as coherent diffraction imaging, holography, plasma diagnostics, or pump-probe experiments, it is desirable to have control over the wave front (WF) of the HHs to maximize the number of XUV photons on target or to tailor the WF. Here, we demonstrate control of the XUV WF by tailoring the driving IR WF with a deformable mirror. The WFs of both IR and XUV beams are monitored with WF sensors. We present a systematic study of the dependence of the aberrations of the HHs on the aberrations of the driving IR laser and explain the observations with propagation simulations. We show that we can control the astigmatism of the HHs by changing the astigmatism of the driving IR laser without compromising the HH generation efficiency with a WF quality from lambda/8 to lambda/13.3. This allows us to shape the XUV beam without changing any XUV optical element.
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