| 1. |
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| 2. |
- Glasbey, JC, et al.
(author)
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- 2021
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| 3. |
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| 4. |
- Bravo, L, et al.
(author)
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- 2021
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swepub:Mat__t
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| 5. |
- Tabiri, S, et al.
(author)
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- 2021
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| 10. |
- Turcu, I. C. E., et al.
(author)
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HIGH FIELD PHYSICS AND QED EXPERIMENTS AT ELI-NP
- 2016
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In: Romanian Reports on Physics. - 1221-1451 .- 1841-8759. ; 68, s. S145-S231
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Journal article (peer-reviewed)abstract
- ELI-NP facility will enable for the first time the use of two 10 PW laser beams for quantum electrodynamics (QED) experiments. The first beam will accelerate electrons to relativistic energies. The second beam will subject relativistic electrons to the strong electromagnetic field generating QED processes: intense gamma ray radiation and electron-positron pair formation. The laser beams will be focused to intensities above 10(21) Wcm(-2) and reaching 10(22)-10(23) Wcm(-2) for the first time. We propose to use this capability to investigate new physical phenomena at the interfaces of plasma, nuclear and particle physics at ELI-NP. This High Power Laser System Technical Design Report (HPLS-TDR2) presents the experimental area E6 at ELI-NP for investigating high field physics and quantum electrodynamics and the production of electron-positron-pairs and of energetic gamma-rays. The scientific community submitted 12 commissioning runs for E6 interaction chamber with two 10 PW laser beams and one proposal for the CETAL interaction chamber with 1 PW laser. The proposals are representative of the international high field physics community being written by 48 authors from 14 European and US organizations. The proposals are classified according to the science area investigated into: Radiation Reaction Physics: Classical and Quantum; Compton and Thomson Scattering Physics: Linear and Non Linear Regimes; QED in Vacuum; Atoms in Extreme Fields. Two pump-probe colliding 10 PW laser beams are proposed for the E6 interaction chamber. The focused pump laser beam accelerates the electrons to relativistic energies. The accelerated electron bunches interact with the very high electro-magnetic field of the focused probe laser beam. We propose two main types of experiments with: (a) gas targets in which the pump laser-beam is focused by a long focal length mirror and drives a wakefield in which the electron bunch is accelerated to multi-GeV energies and then exposed to the EM field of the probe laser which is tightly focused; (b) solid targets in which both the pump and probe laser beams are focused on the solid target, one accelerating the electrons in the solid and the other, delayed, providing the high electric field to which the relativistic electrons are subjected. We propose four main focusing configurations for the pump and probe laser beams, two for each type of target: counter-propagating 10 PW focused laser beams and the two 10 PW laser beams focused in the same direction. For solid targets we propose an additional configuration with plasma-mirror on the pump laser beam: the plasma mirror placed between the focusing mirror and target. It is proposed that the 10 PW laser beams will have polarization control and focus control by means of adaptive optics. Initially only one 10 PW may have polarization control and adaptive optics. In order to accommodate the two laser beams and diagnostics the proposed interaction chamber is quasi-octagonal with a diameter of 4.5 m. A large electron-spectrometer is proposed for multi-GeV electrons. Other diagnostics are requested for: gamma-rays, electrons and positrons, protons and ions, plasma characterization, transmitted and reflected laser beam. Targets will be provided by the ELI-NP Target Laboratory or purchased. The E6 experiments and diagnostics will benefit from the ELI-NP Electronics Laboratory, the Workshop and the Optics Laboratory. In order to ensure radiation-protection, a large beam-dump is planned for both multi-GeV electrons and multi-100 MeV protons.
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| 11. |
- MacLellan, D. A., et al.
(author)
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Annular Fast Electron Transport in Silicon Arising from Low-Temperature Resistivity
- 2013
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In: Physical Review Letters. - 1079-7114. ; 111:9
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Journal article (peer-reviewed)abstract
- Fast electron transport in Si, driven by ultraintense laser pulses, is investigated experimentally and via 3D hybrid particle-in-cell simulations. A transition from a Gaussian-like to an annular fast electron beam profile is demonstrated and explained by resistively generated magnetic fields. The results highlight the potential to completely transform the beam transport pattern by tailoring the resistivity-temperature profile at temperatures as low as a few eV.
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| 12. |
- McKenna, P., et al.
(author)
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Effects of front surface plasma expansion on proton acceleration in ultraintense laser irradiation of foil targets
- 2008
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In: Laser and Particle Beams. - 0263-0346. ; 26:4, s. 591-596
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Journal article (peer-reviewed)abstract
- The properties of beams of high energy protons accelerated during ultraintense, picosecond laser-irradiation of thin foil targets are investigated as a function of preplasma expansion at the target front surface. Significant enhancement in the maximum proton energy and laser-to-proton energy conversion efficiency is observed at optimum preplasma density gradients due, to self-focusing Of the incident laser pulse. For very long preplasma expansion, the propagating laser pulse is observed to filament, resulting in highly uniform proton beams, but with reduced flux and maximum energy.
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| 13. |
- Pirozhkov, A. S., et al.
(author)
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Diagnostic of laser contrast using target reflectivity
- 2009
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 94:24
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Journal article (peer-reviewed)abstract
- Using three different laser systems, we demonstrate a convenient and simple plasma based diagnostic of the contrast of high-power short-pulse lasers. The technique is based on measuring the specular reflectivity from a solid target. The reflectivity remains high even at relativistic intensities above 10(19) W/cm(2) in the case of a high-contrast prepulse-free laser. On the contrary, the specular reflectivity drops with increasing intensities in the case of systems with insufficient contrast due to beam breakup and increased absorption caused by preplasma.
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| 14. |
- Alfirevic, A., et al.
(author)
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Phenotype Standardization for Statin-Induced Myotoxicity
- 2014
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In: Clinical Pharmacology and Therapeutics. - : Springer Science and Business Media LLC. - 0009-9236 .- 1532-6535. ; 96:4, s. 470-476
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Research review (peer-reviewed)abstract
- Statins are widely used lipid-lowering drugs that are effective in reducing cardiovascular disease risk. Although they are generally well tolerated, they can cause muscle toxicity, which can lead to severe rhabdomyolysis. Research in this area has been hampered to some extent by the lack of standardized nomenclature and phenotypic definitions. We have used numerical and descriptive classifications and developed an algorithm to define statin-related myotoxicity phenotypes, including myalgia, myopathy, rhabdomyolysis, and necrotizing autoimmune myopathy.
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| 15. |
- Carroll, DC, et al.
(author)
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Active manipulation of the spatial energy distribution of laser-accelerated proton beams
- 2007
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In: Physical Review E (Statistical, Nonlinear, and Soft Matter Physics). - 1539-3755. ; 76:065401(R), s. 1-065401
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Journal article (peer-reviewed)abstract
- The spatial energy distributions of beams of protons accelerated by ultrahigh intensity (>10^19 W/cm2) picosecond laser pulse interactions with thin foil targets are investigated. Using separate, low intensity (<10^13 W/cm2) nanosecond laser pulses, focused onto the front surface of the target foil prior to the arrival of the high intensity pulse, it is demonstrated that the proton beam profile can be actively manipulated. In particular, results obtained with an annular intensity distribution at the focus of the low intensity beam are presented, showing smooth proton beams with a sharp circular boundary at all energies, which represents a significant improvement in the beam quality compared to irradiation with the picosecond beam alone.
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| 16. |
- Coury, M., et al.
(author)
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Injection and transport properties of fast electrons in ultraintense laser-solid interactions
- 2013
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In: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 20:4
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Journal article (peer-reviewed)abstract
- Fast electron injection and transport in solid foils irradiated by sub-picosecond-duration laser pulses with peak intensity equal to 4 x 10(20)W/cm(2) is investigated experimentally and via 3D simulations. The simulations are performed using a hybrid-particle-in-cell (PIC) code for a range of fast electron beam injection conditions, with and without inclusion of self-generated resistive magnetic fields. The resulting fast electron beam transport properties are used in rear-surface plasma expansion calculations to compare with measurements of proton acceleration, as a function of target thickness. An injection half-angle of similar to 50 degrees - 70 degrees is inferred, which is significantly larger than that derived from previous experiments under similar conditions. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4799726]
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| 17. |
- Dey, Lankeswar, et al.
(author)
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Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using Its General Relativity Centenary Flare : Improved Orbital Parameters
- 2018
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In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 866:1
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Journal article (peer-reviewed)abstract
- Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects of certain hereditary contributions to GW emission are required to predict impact flare timings of OJ 287. We develop an approach that incorporates this effect into the BBH model for OJ 287. This allows us to demonstrate an excellent agreement between the observed impact flare timings and those predicted from ten orbital cycles of the BBH central engine model. The deduced rate of orbital period decay is nine orders of magnitude higher than the observed rate in PSR 1913+16, demonstrating again the relativistic nature of OJ 287's central engine. Finally, we argue that precise timing of the predicted 2019 impact flare should allow a test of the celebrated black hole no-hair theorem at the 10% level.
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| 18. |
- MacLellan, D A, et al.
(author)
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Tunable mega-ampere electron current propagation in solids by dynamic control of lattice melt.
- 2014
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In: Physical Review Letters. - 1079-7114. ; 113:18
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Journal article (peer-reviewed)abstract
- The influence of lattice-melt-induced resistivity gradients on the transport of mega-ampere currents of fast electrons in solids is investigated numerically and experimentally using laser-accelerated protons to induce isochoric heating. Tailoring the heating profile enables the resistive magnetic fields which strongly influence the current propagation to be manipulated. This tunable laser-driven process enables important fast electron beam properties, including the beam divergence, profile, and symmetry to be actively tailored, and without recourse to complex target manufacture.
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| 19. |
- McKenna, P., et al.
(author)
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Lateral electron transport in high-intensity laser-irradiated foils diagnosed by ion emission
- 2007
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In: Physical Review Letters. - 1079-7114. ; 98:14
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Journal article (peer-reviewed)abstract
- An experimental investigation of lateral electron transport in thin metallic foil targets irradiated by ultraintense (>= 10(19) W/cm(2)) laser pulses is reported. Two-dimensional spatially resolved ion emission measurements are used to quantify electric-field generation resulting from electron transport. The measurement of large electric fields (similar to 0.1 TV/m) millimeters from the laser focus reveals that lateral energy transport continues long after the laser pulse has decayed. Numerical simulations confirm a very strong enhancement of electron density and electric field at the edges of the target.
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| 20. |
- Nuernberg, F., et al.
(author)
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Radiochromic film imaging spectroscopy of laser-accelerated proton beams
- 2009
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In: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 80:3
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Journal article (peer-reviewed)abstract
- This article reports on an experimental method to fully reconstruct laser-accelerated proton beam parameters called radiochromic film imaging spectroscopy (RIS). RIS allows for the characterization of proton beams concerning real and virtual source size, envelope- and microdivergence, normalized transverse emittance, phase space, and proton spectrum. This technique requires particular targets and a high resolution proton detector. Therefore thin gold foils with a microgrooved rear side were manufactured and characterized. Calibrated GafChromic radiochromic film (RCF) types MD-55, HS, and HD-810 in stack configuration were used as spatial and energy resolved film detectors. The principle of the RCF imaging spectroscopy was demonstrated at four different laser systems. This can be a method to characterize a laser system with respect to its proton-acceleration capability. In addition, an algorithm to calculate the spatial and energy resolved proton distribution has been developed and tested to get a better idea of laser-accelerated proton beams and their energy deposition with respect to further applications.
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| 21. |
- Robinson, A. P. L., et al.
(author)
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Spectral modification of laser-accelerated proton beams by self-generated magnetic fields
- 2009
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In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 11
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Journal article (peer-reviewed)abstract
- Target normal measurements of proton energy spectra from ultrathin (50-200 nm) planar foil targets irradiated by 10(19) W cm(-2) 40 fs laser pulses exhibit broad maxima that are not present in the energy spectra from micron thickness targets (6 mu m). The proton flux in the peak is considerably greater than the proton flux observed in the same energy range in thicker targets. Numerical modelling of the experiment indicates that this spectral modification in thin targets is caused by magnetic fields that grow at the rear of the target during the laser-target interaction.
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| 22. |
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| 23. |
- Yuan, X. H., et al.
(author)
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Effects of target pre-heating and expansion on terahertz radiation production from intense laser-solid interactions
- 2014
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In: High Power Laser Science and Engineering. - : Cambridge University Press (CUP). - 2095-4719 .- 2052-3289. ; 2
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Journal article (peer-reviewed)abstract
- The first experimental measurements of intense laser-driven terahertz (THz) radiation from a solid target which is preheated by an intense pulse of laser-accelerated protons is reported. The total energy of the THz radiation is found to decrease by approximately a factor of 2 compared to a cold target reference. This is attributed to an increase in the scale length of the preformed plasma, driven by proton heating, at the front surface of the target, where the THz radiation is generated. The results show the importance of controlling the preplasma scale length for THz production.
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| 24. |
- Alfredsson, Joakim, et al.
(author)
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Predicting the risk of bleeding during dual antiplatelet therapy after acute coronary syndromes
- 2017
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In: Heart. - : BMJ PUBLISHING GROUP. - 1355-6037 .- 1468-201X. ; 103:15, s. 1168-1176
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Journal article (peer-reviewed)abstract
- Objectives Dual antiplatelet therapy (DAPT) with aspirin + a P2Y12 inhibitor is recommended for at least 12 months for patients with acute coronary syndrome (ACS), with shorter durations considered for patients with increased bleeding risk. However, there are no decision support tools available to predict an individual patients bleeding risk during DAPT treatment in the post-ACS setting. Methods To develop a longitudinal bleeding risk prediction model, we analysed 9240 patients with unstable angina/non-ST segment elevation myocardial infarction (NSTEMI) from the Targeted Platelet Inhibition to Clarify the Optimal Strategy to Medically Manage Acute Coronary Syndromes (TRILOGY ACS) trial, who were managed without revascularisation and treated with DAPT for a median of 14.8 months. Results We identified 10 significant baseline predictors of non-coronary artery bypass grafting (CABG)-related Global Use of Strategies to Open Occluded Arteries (GUSTO) severe/life-threatening/moderate bleeding: age, sex, weight, NSTEMI (vs unstable angina), angiography performed before randomisation, prior peptic ulcer disease, creatinine, systolic blood pressure, haemoglobin and treatment with beta-blocker. The five significant baseline predictors of Thrombolysis In Myocardial Infarction (TIMI) major or minor bleeding included age, sex, angiography performed before randomisation, creatinine and haemoglobin. The models showed good predictive accuracy with Therneaus C-indices: 0.78 (SE=0.024) for the GUSTO model and 0.67 (SE=0.023) for the TIMI model. Internal validation with bootstrapping gave similar C-indices of 0.77 and 0.65, respectively. External validation demonstrated an attenuated C-index for the GUSTO model (0.69) but not the TIMI model (0.68). Conclusions Longitudinal bleeding risks during treatment with DAPT in patients with ACS can be reliably predicted using selected baseline characteristics. The TRILOGY ACS bleeding models can inform riskbenefit considerations regarding the duration of DAPT following ACS.
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| 25. |
- Brenner, C. M., et al.
(author)
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Dependence of laser accelerated protons on laser energy following the interaction of defocused, intense laser pulses with ultra-thin targets
- 2011
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In: Laser and Particle Beams. - 0263-0346. ; 29:3, s. 345-351
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Journal article (peer-reviewed)abstract
- The scaling of the flux and maximum energy of laser-driven sheath-accelerated protons has been investigated as a function of laser pulse energy in the range of 15-380 mJ at intensities of 10(16)-10(18) W/cm(2). The pulse duration and target thickness were fixed at 40 fs and 25 nm, respectively, while the laser focal spot size and drive energy were varied. Our results indicate that while the maximum proton energy is dependent on the laser energy and laser spot diameter, the proton flux is primarily related to the laser pulse energy under the conditions studied here. Our measurements show that increasing the laser energy by an order of magnitude results in a more than 500-fold increase in the observed proton flux. Whereas, an order of magnitude increase in the laser intensity generated by decreasing the laser focal spot size, at constant laser energy, gives rise to less than a tenfold increase in observed proton flux.
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| 26. |
- Carroll, D. C., et al.
(author)
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A modified Thomson parabola spectrometer for high resolution multi-MeV ion measurements-Application to laser-driven ion acceleration
- 2010
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In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 620:1, s. 23-27
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Conference paper (peer-reviewed)abstract
- A novel Thomson parabola ion spectrometer design is presented, in which a gradient electric field configuration is employed to enable a compact design capable of high resolution measurements of ion energy and charge-to-mass ratio. Practical issues relating to the use of the spectrometer for measurement of ion acceleration in high-power laser-plasma experiments are discussed. Example experimental results for ion acceleration from petawatt-class laser interactions with thin gold target foils are presented. (C) 2010 Elsevier B.V. All rights reserved.
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| 27. |
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| 28. |
- Clarke, R. J., et al.
(author)
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Detection of short lived radioisotopes as a fast diagnostic for intense laser-solid interactions
- 2006
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:14
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Journal article (peer-reviewed)abstract
- As a diagnostic of high-intensity laser interactions (> 10(19) W cm(-2)), the detection of radioactive isotopes is regularly used for the characterization of proton, neutron, ion, and photon beams. This involves sample removal from the interaction chamber and time consuming post shot analysis using NaI coincidence counting or Ge detectors. This letter describes the use of in situ detectors to measure laser-driven (p,n) reactions in Al-27 as an almost real-time diagnostic for proton acceleration. The produced Si-27 isotope decays with a 4.16 s half-life by the predominantly beta+ emission, producing a strong 511 keV annihilation peak. (c) 2006 American Institute of Physics.
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| 29. |
- Coury, M., et al.
(author)
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Influence of laser irradiated spot size on energetic electron injection and proton acceleration in foil targets
- 2012
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 100:7
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Journal article (peer-reviewed)abstract
- The influence of irradiated spot size on laser energy coupling to electrons, and subsequently to protons, in the interaction of intense laser pulses with foil targets is investigated experimentally. Proton acceleration is characterized for laser intensities ranging from 2 x 10(18) - 6 x 10(20) W/cm(2), by (1) variation of the laser energy for a fixed irradiated spot size, and (2) by variation of the spot size for a fixed energy. At a given laser pulse intensity, the maximum proton energy is higher under defocus illumination compared to tight focus and the results are explained in terms of geometrical changes to the hot electron injection. (C) 2012 American Institute of Physics. [doi:10.1063/1.3685615]
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| 30. |
- Gray, R. J., et al.
(author)
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Laser pulse propagation and enhanced energy coupling to fast electrons in dense plasma gradients
- 2014
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In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 16
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Journal article (peer-reviewed)abstract
- Laser energy absorption to fast electrons during the interaction of an ultra-intense (10(20) Wcm(-2)), picosecond laser pulse with a solid is investigated, experimentally and numerically, as a function of the plasma density scale length at the irradiated surface. It is shown that there is an optimum density gradient for efficient energy coupling to electrons and that this arises due to strong self-focusing and channeling driving energy absorption over an extended length in the preformed plasma. At longer density gradients the laser filaments, resulting in significantly lower overall energy coupling. As the scale length is further increased, a transition to a second laser energy absorption process is observed experimentally via multiple diagnostics. The results demonstrate that it is possible to significantly enhance laser energy absorption and coupling to fast electrons by dynamically controlling the plasma density gradient.
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| 31. |
- Green, J. S., et al.
(author)
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Enhanced proton flux in the MeV range by defocused laser irradiation
- 2010
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In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 12
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Journal article (peer-reviewed)abstract
- Thin Al foils (50 nm and 6 mu m) were irradiated at intensities of up to 2x10(19) W cm(-2) using high contrast (10(8)) laser pulses. Ion emission from the rear of the targets was measured using a scintillator-based Thomson parabola and beam sampling 'footprint' monitor. The variation of the ion spectra and beam profile with focal spot size was systematically studied. The results show that while the maximum proton energy is achieved around tight focus for both target thicknesses, as the spot size increases the ion flux at lower energies is seen to peak at significantly increased spot sizes. Measurements of the proton footprint, however, show that the off-axis proton flux is highest at tight focus, indicating that a previously identified proton deflection mechanism may alter the on-axis spectrum. One-dimensional particle-in-cell modelling of the experiment supports our hypothesis that the observed change in spectra with focal spot size is due to the competition of two effects: decrease in laser intensity and an increase in proton emission area.
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| 32. |
- Gurbel, Paul A., et al.
(author)
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Platelet Function During Extended Prasugrel and Clopidogrel Therapy for Patients With ACS Treated Without Revascularization The TRILOGY ACS Platelet Function Substudy
- 2012
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In: JAMA: The Journal of the American Medical Association. - : American Medical Association (AMA). - 1538-3598. ; 308:17, s. 1785-1794
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Journal article (peer-reviewed)abstract
- Context The relationship of platelet function testing measurements with outcomes in patients with acute coronary syndromes (ACS) initially managed medically without revascularization is unknown. Objective To characterize the differences and evaluate clinical outcomes associated with platelet reactivity among patients with ACS treated with clopidogrel or prasugrel. Design, Setting, and Patients Patients with medically managed unstable angina or non-ST-segment elevation myocardial infarction were enrolled in the TRILOGY ACS trial (2008 to 2011) comparing clopidogrel vs prasugrel. Of 9326 participants, 27.5% were included in a platelet function substudy: 1286 treated with prasugrel and 1278 treated with clopidogrel. Interventions Aspirin with either prasugrel (10 or 5 mg/d) or clopidogrel (75 mg/d); those 75 years or older and younger than 75 years but who weighed less than 60 kg received a 5-mg prasugrel maintenance dose. Main Outcome Measures Platelet reactivity, measured in P2Y(12) reaction units (PRUs), was performed at baseline, at 2 hours, and at 1, 3, 6, 12, 18, 24, and 30 months after randomization. The primary efficacy end point was a composite of cardiovascular death, myocardial infarction, or stroke through 30 months. Results Among participants younger than 75 years and weighing 60 kg or more, the median PRU values at 30 days were 64 (interquartile range [IQR], 33-128) in the prasugrel group vs 200 (IQR, 141-260) in the clopidogrel group (P<.001), a difference that persisted through all subsequent time points. For participants younger than 75 years and weighing less than 60 kg, the median 30-day PRU values were 139 (IQR, 86-203) for the prasugrel group vs 209 (IQR, 148-283) for the clopidogrel group (P<.001), and for participants 75 years or older, the median PRU values were 164 (IQR, 105-216) for the prasugrel group vs 222 (IQR, 148-268) for the clopidogrel group (P<.001). At 30 months the rate of the primary efficacy end point was 17.2% (160 events) in the prasugrel group vs 18.9% (180 events) in the clopidogrel group (P=.29). There were no significant differences in the continuous distributions of 30-day PRU values for participants with a primary efficacy end point event after 30 days (n=214) compared with participants without an event (n=1794; P=.07) and no significant relationship between the occurence of the primary efficacy end point and continuous PRU values (adjusted hazard ratio [HR] for increase of 60 PRUs, 1.03; 95% CI, 0.96-1.11; P=.44). Similar findings were observed with 30-day PRU cut points used to define high on-treatment platelet reactivity-PRU more than 208 (adjusted HR, 1.16; 95% CI, 0.89-1.52, P=.28) and PRU more than 230 (adjusted HR, 1.20; 95% CI, 0.90-1.61; P=.21). Conclusions Among patients with ACS without ST-segment elevation and initially managed without revascularization, prasugrel was associated with lower platelet reactivity than clopidogrel, irrespective of age, weight, and dose. Among those in the platelet substudy, no significant differences existed between prasugrel vs clopidogrel in the occurence of the primary efficacy end point through 30 months and no significant association existed between platelet reactivity and occurrence of ischemic outcomes.
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| 33. |
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| 34. |
- Hess, Connie N., et al.
(author)
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Differential occurrence, profile, and impact of first recurrent cardiovascular events after an acute coronary syndrome
- 2017
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In: American Heart Journal. - : MOSBY-ELSEVIER. - 0002-8703 .- 1097-6744. ; 187, s. 194-203
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Journal article (peer-reviewed)abstract
- Objective Acute coronary syndrome (ACS) trials typically use a composite primary outcome (myocardial infarction [MI], stroke, or cardiovascular death), but differential patient characteristics, timing, and consequences associated with individual component end points as first events have not been well studied. We compared patient characteristics and prognostic significance associated with first cardiovascular events in the post-ACS setting for initially stabilized patients. Methods We combined patient-level data from 4 trials of post-ACS antithrombotic therapies (PLATO, APPRAISE-2, TRACER, and TRILOGY ACS) to characterize the timing of and characteristics associated with first cardiovascular events (MI, stroke, or cardiovascular death). Landmark analysis at 7 days after index ACS presentation was used to focus on spontaneous, postdischarge events that were not confounded by in-hospital procedural complications. Using a competing risk framework, we tested for differential associations between prespecified covariates and the occurrence of nonfatal stroke vs MI as the first event, and we examined subsequent events after the first nonfatal event. Results Among 46,694 patients with a median follow-up of 358 (25th, 75th percentiles 262, 486) days, a first ischemic event occurred in 4,307 patients (9.2%) as follows: MI in 5.8% (n = 2,690), stroke in 1.0% (n = 477), and cardiovascular death in 2.4% (n = 1,140). Older age, prior stroke/transient ischemic attack, prior atrial fibrillation, and higher diastolic blood pressure were associated with a significantly greater risk of stroke vs MI, whereas prior percutaneous coronary intervention was associated with a greater risk of MI vs stroke. Second events occurred in 32% of those with a first nonfatal stroke at a median of 13 (3, 59) days after the first event and in 32% of those with a first nonfatal MI at a median of 35 (5, 137) days after the first event. The most common second event was a recurrent MI among those with MI as the first event and cardiovascular death among those with stroke as the first event. Conclusions Approximately 9% of patients experienced a first cardiovascular event in the post-ACS setting during a median follow-up of 1 year. Although the profile and prognostic implications of stroke vs MI as the first nonfatal event differ substantially, approximately one-third of these patients experienced a second event, typically soon after the first event. These findings have implications for improving post-ACS care and influencing the design of future cardiovascular trials.
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| 35. |
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| 36. |
- Martson, A-G, et al.
(author)
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How to design a study to evaluate therapeutic drug monitoring in infectious diseases?
- 2020
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In: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 26:8, s. 1008-1016
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Research review (peer-reviewed)abstract
- Background: Therapeutic drug monitoring (TDM) is a tool to personalize and optimize dosing by measuring the drug concentration and subsequently adjusting the dose to reach a target concentration or exposure. The evidence to support TDM is however often ranked as expert opinion. Limitations in study design and sample size have hampered definitive conclusions of the potential added value of TDM.Objectives: We aim to give expert opinion and discuss the main points and limitations of available data from antibiotic TDM trials and emphasize key elements for consideration in design of future clinical studies to quantify the benefits of TDM.Sources: The sources were peer-reviewed publications, guidelines and expert opinions from the field of TDM.Content: This review focuses on key aspects of antimicrobial TDM study design: describing the rationale for a TDM study, assessing the exposure of a drug, assessing susceptibility of pathogens and selecting appropriate clinical endpoints. Moreover we provide guidance on appropriate study design.
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| 37. |
- McKenna, P., et al.
(author)
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Effect of Lattice Structure on Energetic Electron Transport in Solids Irradiated by Ultraintense Laser Pulses
- 2011
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In: Physical Review Letters. - 1079-7114. ; 106:18
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Journal article (peer-reviewed)abstract
- The effect of lattice structure on the transport of energetic (MeV) electrons in solids irradiated by ultraintense laser pulses is investigated using various allotropes of carbon. We observe smooth electron transport in diamond, whereas beam filamentation is observed with less ordered forms of carbon. The highly ordered lattice structure of diamond is shown to result in a transient state of warm dense carbon with metalliclike conductivity, at temperatures of the order of 1-100 eV, leading to suppression of electron beam filamentation.
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| 38. |
- Shimada, Yuichi J., et al.
(author)
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Impact of glycoprotein IIb/IIIa inhibitors on the efficacy and safety of ticagrelor compared with clopidogrel in patients with acute coronary syndromes : Analysis from the Platelet Inhibition and Patient Outcomes (PLATO) Trial
- 2016
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In: American Heart Journal. - : Elsevier BV. - 0002-8703 .- 1097-6744. ; 177, s. 1-8
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Journal article (peer-reviewed)abstract
- Background Ticagrelor reduced cardiovascular events compared with clopidogrel in PLATO without increasing overall major bleeding. We evaluated whether the use of glycoprotein IIb/IIIa inhibitor (GPI) impacts the relative efficacy and safety of ticagrelor compared with clopidogrel. Methods PLATO randomized 18,624 subjects with acute coronary syndrome to ticagrelor versus clopidogrel. The primary efficacy end point was cardiovascular death/myocardial infarction/stroke, and the primary safety end point was major bleeding. The use of GPI was at the physician's discretion and open-label. We evaluated outcomes at 30 days stratified by GPI use in the subgroup of 9,983 patients who underwent percutaneous coronary intervention (PCI) within 72 hours. Results A total of 4,020 (40%) received a GPI. Those receiving a GPI were more likely to be younger, be male, and undergo multivessel PCI. There was no interaction between treatment and GPI use for the primary efficacy and safety end points. Patients treated without GPI had a lower rate of definite stent thrombosis and higher rate of minor/major bleeding with ticagrelor compared with clopidogrel (P<.05), whereas there was no such difference with GPI (P interaction <.05). Conclusions In patients with acute coronary syndrome undergoing early PCI, the efficacy and safety of ticagrelor as compared with clopidogrel were not modified by GPI use according to the primary efficacy and safety end point of the trial, although there were indications of greater benefit on definite stent thrombosis and more major or minor bleeding with ticagrelor in patients without (vs with) GPI treatment.
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| 39. |
- Xu, M. H., et al.
(author)
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Enhancement of ion generation in femtosecond ultraintense laser-foil interactions by defocusing
- 2012
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 100:8
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Journal article (peer-reviewed)abstract
- A simple method to enhance ion generation with femtosecond ultraintense lasers is demonstrated experimentally by defocusing laser beams on target surface. When the laser is optimally defocused, we find that the population of medium and low energy protons from ultra-thin foils is increased significantly while the proton cutoff energy is almost unchanged. In this way, the total proton yield can be enhanced by more than 1 order, even though the peak laser intensity drops. The depression of the amplified spontaneous emission (ASE) effect and the population increase of moderate-energy electrons are believed to be the main reasons for the effective enhancement. (C) 2012 American Institute of Physics. [doi:10.1063/1.3688027]
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| 40. |
- Aurand, Bastian, et al.
(author)
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A setup for studies of laser-driven proton acceleration at the Lund Laser Centre
- 2015
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In: Laser and Particle Beams. - 0263-0346. ; 33:1, s. 59-64
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Journal article (peer-reviewed)abstract
- We report on a setup for the investigation of proton acceleration in the regime of target normal sheath acceleration. The main interest here is to focus on stable laser beam parameters as well as a reliable target setup and diagnostics in order to do extensive and systematic studies on the acceleration mechanism. A motorized target alignment system in combination with large target mounts allows for up to 340 shots with high repetition rate without breaking the vacuum. This performance is used to conduct experiments with a split mirror setup exploring the effect of spatial and temporal separation between the pulses on the acceleration mechanism and on the resulting proton beam.
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| 41. |
- Aurand, B., et al.
(author)
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Manipulation of the spatial distribution of laser-accelerated proton beams by varying the laser intensity distribution
- 2016
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In: Physics of Plasmas. - : AIP Publishing. - 1089-7674 .- 1070-664X. ; 23:2
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Journal article (peer-reviewed)abstract
- We report on a study of the spatial profile of proton beams produced through target normal sheath acceleration using flat target foils and changing the laser intensity distribution on the target front surface. This is done by either defocusing a single laser pulse or by using a split-pulse setup and irradiating the target with two identical laser pulses with variable spatial separation. The resulting proton beam profile and the energy spectrum are recorded as functions of the focal spot size of the single laser pulse and of the separation between the two pulses. A shaping of the resulting proton beam profile, related to both an increase in flux of low-energy protons in the target normal direction and a decrease in their divergence, in one or two dimensions, is observed. The results are explained by simple modelling of rear surface sheath field expansion, ionization, and projection of the resulting proton beam.
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| 42. |
- Chan, Mark Y., et al.
(author)
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Temporal biomarker profiling reveals longitudinal changes in risk of death or myocardial infarction in Non-ST-segment elevation acute coronary syndrome
- 2017
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In: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 63:7, s. 1214-1226
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Journal article (peer-reviewed)abstract
- BACKGROUND: There are conflicting data on whether changes in N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity C-reactive protein (hs-CRP) concentrations between time points (delta NT-proBNP and hs-CRP) are associated with a change in prognosis. METHODS: We measured NT-proBNP and hs-CRP at 3 time points in 1665 patients with non-ST-segment elevation acute coronary syndrome (NSTEACS). Cox proportional hazards was applied to the delta between temporal measurements to determine the continuous association with cardiovascular events. Effect estimates for delta NT-proBNP and hs-CRP are presented per 40% increase as the basic unit of temporal change. RESULTS: Median NT-proBNP was 370.0 (25th, 75th percentiles, 130.0, 996.0), 340.0 (135.0, 875.0), and 267.0 (111.0, 684.0) ng/L; and median hs-CRP was 4.6 (1.7, 13.1), 1.9 (0.8, 4.5), and 1.8 (0.8, 4.4) mg/L at baseline, 30 days, and 6 months, respectively. The deltas between baseline and 6 months were the most prognostically informative. Every 40% increase of delta NTproBNP (baseline to 6 months) was associated with a 14% greater risk of cardiovascular death (adjusted hazard ratio (HR) 1.14, 95% CI, 1.03-1.27) and with a 14% greater risk of all-cause death (adjusted HR 1.14, 95% CI, 1.04 -1.26), while every 40% increase of delta hs- CRP (baseline to 6 months) was associated with a 9% greater risk of the composite end point (adjusted HR 1.09, 95% CI, 1.02-1.17) and a 10% greater risk of myocardial infarction (adjusted HR 1.10, 95%, CI 1.00 -1.20). CONCLUSIONS: Temporal changes in NT-proBNP and hs-CRP are quantitatively associated with future cardiovascular events, supporting their role in dynamic risk stratification of NSTEACS.
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| 43. |
- Cherniack, Martin, et al.
(author)
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The Hand-Arm Vibration International Consortium (HAVIC) : prospective studies on the relationship between power tool exposure and health effects.
- 2007
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In: Journal of Occupational and Environmental Medicine. - 1076-2752 .- 1536-5948. ; 49:3, s. 289-301
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Journal article (peer-reviewed)abstract
- OBJECTIVES: The Hand-Arm Vibration International Consortium (HAVIC) is a collaboration of investigators from Europe and North America studying health effects from hand-arm vibration (HAV). Features include prospective design, cross-cohort exposure, and health assessment methods. METHODS: Two new cohorts (dental hygienists and dental hygiene students), two existing cohorts (Finnish forest workers, and Swedish truck cab assemblers), and a previous population (US shipyard workers) are included. Instruments include surveys, quantitative medical tests, physical examination, and work simulation and data logging to assess exposure. New methods were developed for nerve conduction and data logging. RESULTS: Findings on the relationship between nerve conduction and skin temperature in HAV-exposed subjects resulted in a new approach to subject warming. CONCLUSIONS: Integrating established cohorts has advantages over de novo cohort construction. Complex laboratory tests can be successfully adapted for field use.
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| 44. |
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| 45. |
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| 46. |
- Cornel, Jan H., et al.
(author)
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Anticoagulant therapy and outcomes in patients with prior or acute heart failure and acute coronary syndromes : Insights from the APixaban for PRevention of Acute ISchemic Events 2 trial
- 2015
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In: American Heart Journal. - : Elsevier BV. - 0002-8703 .- 1097-6744. ; 169:4, s. 531-538
-
Journal article (peer-reviewed)abstract
- Background Clinical outcomes and the effects of oral anticoagulants among patients with acute coronary syndrome (ACS) and either a history of or acute heart failure (HF) are largely unknown. We aimed to assess the relationship between prior HF or acute HF complicating an index ACS event and subsequent clinical outcomes and the efficacy and safety of apixaban compared with placebo in these populations. Methods High-risk patients were randomly assigned post-ACS to apixaban 5.0 mg or placebo twice daily. Median follow-up was 8 (4-12) months. The primary outcome was cardiovascular death, myocardial infarction, or stroke. The main safety outcome was thrombolysis in myocardial infarction major bleeding. Results Heart failure was reported in 2,995 patients (41%), either as prior HF (2,076 [28%]) or acute HF (2,028 [27%]). Patients with HF had a very high baseline risk and were more often managed medically. Heart failure was associated with a higher rate of the primary outcome (prior HF: adjusted hazard ratio [HR] 1.73, 95% CI 1.42-2.10, P < .0001, acute HF: adjusted HR 1.65, 95% CI 1.35-2.01, P < .0001) and cardiovascular death (prior HF: HR 2.54, 95% CI 1.82-3.54, acute HF: adjusted HR 2.52, 95% CI 1.82-3.50). Patients with acute HF also had significantly higher rates of thrombolysis in myocardial infarction major bleeding (prior HF: adjusted HR 1.22, 95% CI 0.65-2.27, P = .54, acute HF: adjusted HR 1.78, 95% CI 1.03-3.08, P = .04). There was no statistical evidence of a differential effect of apixaban on clinical events or bleeding in patients with or without prior HF; however, among patients with acute HF, there were numerically fewer events with apixaban than placebo (14.8 vs 19.3, HR 0.76, 95% CI 0.57-1.01, interaction P = .13), a trend that was not seen in patients with prior HF or no HF. Conclusions In high-risk patients post-ACS, both prior and acute HFs are associated with an increased risk of subsequent clinical events. Apixaban did not significantly reduce clinical events and increased bleeding in patients with and without HF; however, there was a tendency toward fewer clinical events with apixaban in patients with acute HF.
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| 47. |
- Cornel, Jan H., et al.
(author)
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Relationship of Platelet Reactivity With Bleeding Outcomes During Long-Term Treatment With Dual Antiplatelet Therapy For Medically Managed Patients With Non-St-Segment Elevation Acute Coronary Syndromes
- 2016
-
In: Journal of the American Heart Association. - 2047-9980. ; 5:11
-
Journal article (peer-reviewed)abstract
- Background--The relationship between "on-treatment" low platelet reactivity and longitudinal risks of major bleeding dual antiplatelet therapy following acute coronary syndromes remains uncertain, especially for patients who do not undergo percutaneous coronary intervention. Methods and Results--We analyzed 2428medicallymanaged acute coronary syndromes patients fromthe Targeted Platelet Inhibition to Clarify the Optimal Strategy to Medically Manage Acute Coronary Syndromes (TRILOGY ACS) trial who had serial platelet reactivity measurements (P2Y12 reaction units; PRUs) and were randomized to aspirin+prasugrel versus aspirin+clopidogrel for up to 30 months. Contal's method was used to determine whether a cut point for steady-state PRU values could distinguish high versus low bleeding risk using 2-level composites: Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) severe/life-threatening or moderate bleeding unrelated to coronary artery bypass grafting (CABG) and non-CABG Thrombolysis In Myocardial Infarction (TIMI) major orminor bleeding. Exploratory analyses used 3-level composites that incorporatedmild andminimalGUSTOand TIMI events.Continuousmeasures of PRUs (per 10-unit decrease)were not independently associatedwith the 2-levelGUSTO (adjusted hazard ratio [HR], 1.01; 95% CI, 0.96-1.06) or TIMI composites (1.02; 0.98-1.07). Furthermore, no PRU cut point could significantly distinguish bleeding risk using the 2-level composites.However, the PRUcut point of 75 differentiated bleeding riskwith the 3-level composites ofGUSTO(26.5% vs 12.6%; adjusted HR, 2.28; 95% CI, 1.77-2.94; P<0.001) and TIMI bleeding events (25.9% vs 12.2%; adjusted HR, 2.30; 95% CI, 1.78-2.97; P<0.001). Conclusions--Among medically managed non-ST-segment elevation acute coronary syndromes patients receiving prolonged dual antiplatelet therapy, PRU values were not significantly associated with the long-term risk of major bleeding events, suggesting that low on-treatment platelet reactivity does not independently predict serious bleeding risk.
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| 48. |
- Derwinger, Anna, et al.
(author)
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Remembering Numbers in Old Age : Mnemonic Training Versus Self-Generated Strategy Training
- 2003
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In: Aging, Neuropsychology and Cognition. - : Routledge. - 1382-5585 .- 1744-4128. ; 10:3, s. 202-214
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Journal article (peer-reviewed)abstract
- The effectiveness of two memory training programs designed to enhance four-digit number recall was examined in 90 healthy older adults. One group received instruction and training in the number-consonant mnemonic, whereas another group was instructed to adopt their own encoding and retrieval strategies to enhance number recall. Also, a control group receiving no training between testing occasions was included. The criterion task was administered according to the Buschke selective reminding procedure. Posttest performance was evaluated with and without cognitive support for remembering (i.e., verbal cues). Under unsupported conditions, the mnemonic group improved number recall following training and the selfgenerated strategy group showed a tendency in the same direction. When support was provided, group differences in favor of the two training groups increased. In addition, no training-related gains were observed in two verbal transfer tasks. The relatively similar patterns of gains in the two intervention groups were discussed in terms of advantages and disadvantages in the two training regimens balancing each other.
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| 49. |
- Domellöf, Magdalena Eriksson, et al.
(author)
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Evaluating a frontostriatal working-memory updating-training paradigm in Parkinson's disease : the iPARK trial, a double-blinded randomized controlled trial
- 2020
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In: BMC Neurology. - : BMC. - 1471-2377. ; 20:1
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Journal article (peer-reviewed)abstract
- Background: Cognitive decline and dementia are common in Parkinson's disease (PD). Cognitive deficits have been linked to the depletion of dopamine in the nigrostriatal pathway, but pharmacological treatments for PD have little evidence of improving or delaying cognitive decline. Therefore, exploring non-pharmacological treatment options is important. There have been some promising results of cognitive training interventions in PD, especially for improvements in working memory and executive functions. Yet, existing studies are often underpowered, lacking appropriate control condition, long term follow-up, a thorough description of the intervention and characteristics of the participants. Working memory updating training has previously shown to increase striatal activation in healthy young and old participants as well as dopaminergic neurotransmission in healthy young participants. In the light of dopamine dysfunction in PD, with negative effects on both motor and cognitive functions it is of interest to study if an impaired striatal system can be responsive to a non-invasive, non-pharmacological intervention. Methods and design: The iPARK trial is a double-blinded, randomized controlled trial with a parallel-group design that aims to recruit 80 patients with PD (during the period 02/2017-02/2023). Included patients need to have PD, Hoehn and Yahr staging I-III, be between 45 to 75 years of age and not have a diagnosis of dementia. All patients will undergo 30 sessions (6-8 weeks) of web-based cognitive training performed from home. The target intervention is a process-based training program targeting working memory updating. The placebo program is a low dose short-term memory program. A battery of neuropsychological tests and questionnaires will be performed before training, directly after training, and 16 weeks after training. Discussion: We expect that the iPARK trial will provide novel and clinically useful information on whether updating training is an effective cognitive training paradigm in PD. Further, it will hopefully contribute to a better understanding of cognitive function in PD and provide answers regarding cognitive plasticity as well as determining critical factors for a responsive striatal system.
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| 50. |
- Hagström, Emil, et al.
(author)
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Association Between Very Low Levels of High-Density Lipoprotein Cholesterol and Long-term Outcomes of Patients With Acute Coronary Syndrome Treated Without Revascularization : Insights From the TRILOGY ACS Trial
- 2016
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In: Clinical Cardiology. - : Wiley. - 0160-9289 .- 1932-8737. ; 39:6, s. 329-337
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Journal article (peer-reviewed)abstract
- Background: Low levels of high-density lipoprotein cholesterol (HDL-C; < 40 mg/dL) are associated with increased risk of cardiovascular events, but it is unclear whether lower thresholds (< 30 mg/dL) are associated with increased hazard.Hypothesis: Very low levels of HDL-C may provide prognostic information in acute coronary syndrome (ACS) patients treated medically without revascularization.Methods: We examined data from 9064/9326 ACS patients enrolled in the TRILOGY ACS trial. Participants were randomized to clopidogrel or prasugrel plus aspirin. Study treatments continued for 6 to 30 months. Relationships between baseline HDL-C and the composite of cardiovascular death, myocardial infarction (MI), or stroke, and individual endpoints of death (cardiovascular and all-cause), MI, and stroke, adjusted for baseline characteristics through 30 months, were analyzed. The HDL-C was evaluated as a dichotomous variable-very low (< 30 mg/dL) vs higher (>= 30 mg/dL)-and continuously.Results: Median baseline HDL-C was 42mg/dL (interquartile range, 34-49mg/dL) with little variation over time. Frequency of the composite endpoint was similar for very low vs higher baseline HDL-C, with no risk difference between groups (hazard ratio [ HR]: 1.13, 95% confidence interval [ CI]: 0.95-1.34). Similar findings were seen for MI and stroke. However, risks for cardiovascular (HR: 1.42, 95% CI: 1.13-1.78) and all-cause death (HR: 1.36, 95% CI: 1.11-1.67) were higher in patients with very low baseline HDL-C.Conclusions: Medically managed ACS patients with very low baseline HDL-C levels have higher risk of long-term cardiovascular and all-cause death but similar risks for nonfatal ischemic outcomes vs patients with higher baseline HDL-C.
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