| 1. |
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| 2. |
- Borges, A. H., et al.
(författare)
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Nonnucleoside Reverse-transcriptase Inhibitor- vs Ritonavir-boosted Protease Inhibitor-based Regimens for Initial Treatment of HIV Infection: A Systematic Review and Metaanalysis of Randomized Trials
- 2016
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 63:2, s. 268-280
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Tidskriftsartikel (refereegranskat)abstract
- Background. Previous studies suggest that nonnucleoside reverse-transcriptase inhibitors (NNRTIs) cause faster virologic suppression, while ritonavir-boosted protease inhibitors (PI/r) recover more CD4 cells. However, individual trials have not been powered to compare clinical outcomes. Methods. We searched databases to identify randomized trials that compared NNRTI-vs PI/r-based initial therapy. A meta-analysis calculated risk ratios (RRs) or mean differences (MDs), as appropriate. Primary outcome was death or progression to AIDS. Secondary outcomes were death, progression to AIDS, and treatment discontinuation. We calculated RR of virologic suppression and MD for an increase in CD4 cells at week 48. Results. We included 29 trials with 9047 participants. Death or progression to AIDS occurred in 226 participants in the NNRTI arm and in 221 in the PI/r arm (RR, 1.03; 95% confidence interval, .87-1.22; 12 trials; n = 3825), death in 205 participants in the NNRTI arm vs 198 in the PI/r arm (1.04; 0.86-1.25; 22 trials; n = 8311), and progression to AIDS in 140 participants in the NNRTI arm vs 144 in the PI/r arm (1.00; 0.80-1.25; 13 trials; n = 4740). Overall treatment discontinuation (1.12; 0.93-1.35; 24 trials; n = 8249) and from toxicity (1.21; 0.87-1.68; 21 trials; n = 6195) were comparable, but discontinuation due to virologic failure was more common with NNRTI (1.58; 0.91-2.74; 17 trials; n = 5371). At week 48, there was no difference between NNRTI and PI/r in virologic suppression (RR, 1.03; 0.98-1.09) or CD4(+) recovery (MD, -4.7 cells; -14.2 to 4.8). Conclusions. We found no difference in clinical and viro-immunologic outcomes between NNRTI-and PI/r-based therapy.
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| 3. |
- Hussein, A. E., et al.
(författare)
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Laser-wakefield accelerators for high-resolution X-ray imaging of complex microstructures
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Laser-wakefield accelerators (LWFAs) are high acceleration-gradient plasma-based particle accelerators capable of producing ultra-relativistic electron beams. Within the strong focusing fields of the wakefield, accelerated electrons undergo betatron oscillations, emitting a bright pulse of X-rays with a micrometer-scale source size that may be used for imaging applications. Non-destructive X-ray phase contrast imaging and tomography of heterogeneous materials can provide insight into their processing, structure, and performance. To demonstrate the imaging capability of X-rays from an LWFA we have examined an irregular eutectic in the aluminum-silicon (Al-Si) system. The lamellar spacing of the Al-Si eutectic microstructure is on the order of a few micrometers, thus requiring high spatial resolution. We present comparisons between the sharpness and spatial resolution in phase contrast images of this eutectic alloy obtained via X-ray phase contrast imaging at the Swiss Light Source (SLS) synchrotron and X-ray projection microscopy via an LWFA source. An upper bound on the resolving power of 2.7 ± 0.3 μm of the LWFA source in this experiment was measured. These results indicate that betatron X-rays from laser wakefield acceleration can provide an alternative to conventional synchrotron sources for high resolution imaging of eutectics and, more broadly, complex microstructures.
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| 4. |
- Spesyvtsev, R., et al.
(författare)
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Generation of electron high energy beams with a ring-like structure by a dual stage laser wakefield accelerator
- 2019
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Ingår i: Relativistic Plasma Waves and Particle Beams as Coherent and Incoherent Radiation Sources III. - : SPIE. - 9781510627383 ; 11036
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Konferensbidrag (refereegranskat)abstract
- The laser wake-field accelerator (LWFA) traditionally produces high brightness, quasi-monoenergetic electron beams with Gaussian-like spatial and angular distributions. In the present work we investigate the generation of ultra-relativistic beams with ring-like structures in the blowout regime of the LWFA using a dual stage accelerator. A density down-ramp triggers injection after the first stage and is used to produce ring-like electron spectra in the 300 - 600 MeV energy range. These well defined, annular beams are observed simultaneously with the on-axis, high energy electron beams, with a divergence of a few milliradians. The rings have quasi-monoenergetic energy spectra with an RMS spread estimated to be less than 5%. Particle-in-cell simulations confirm that off-axis injection provides the electrons with the initial transverse momentum necessary to undertake distinct betatron oscillations within the plasma bubble during their acceleration process.
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| 5. |
- Kettle, B., et al.
(författare)
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Single-Shot Multi-keV X-Ray Absorption Spectroscopy Using an Ultrashort Laser-Wakefield Accelerator Source
- 2019
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Ingår i: Physical Review Letters. - 0031-9007. ; 123:25
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Tidskriftsartikel (refereegranskat)abstract
- Single-shot absorption measurements have been performed using the multi-keV x rays generated by a laser-wakefield accelerator. A 200 TW laser was used to drive a laser-wakefield accelerator in a mode which produced broadband electron beams with a maximum energy above 1 GeV and a broad divergence of ≈15 mrad FWHM. Betatron oscillations of these electrons generated 1.2±0.2×106 photons/eV in the 5 keV region, with a signal-to-noise ratio of approximately 300 1. This was sufficient to allow high-resolution x-ray absorption near-edge structure measurements at the K edge of a titanium sample in a single shot. We demonstrate that this source is capable of single-shot, simultaneous measurements of both the electron and ion distributions in matter heated to eV temperatures by comparison with density functional theory simulations. The unique combination of a high-flux, large bandwidth, few femtosecond duration x-ray pulse synchronized to a high-power laser will enable key advances in the study of ultrafast energetic processes such as electron-ion equilibration.
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| 6. |
- Landegren, N, et al.
(författare)
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AIREing out autoimmunity
- 2015
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Ingår i: SCIENCE TRANSLATIONAL MEDICINE. - 1946-6234. ; 7:292
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 7. |
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| 8. |
- Aurand, Bastian, et al.
(författare)
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A setup for studies of laser-driven proton acceleration at the Lund Laser Centre
- 2015
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Ingår i: Laser and Particle Beams. - 0263-0346. ; 33:1, s. 59-64
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Aurand, B., et al.
(författare)
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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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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1089-7674 .- 1070-664X. ; 23:2
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Tidskriftsartikel (refereegranskat)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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| 10. |
- Axelsson, K. F., et al.
(författare)
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Fracture Risk After Gastric Bypass Surgery : A Retrospective Cohort Study
- 2018
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Ingår i: Osteoporosis International. - : Springer London. - 0937-941X .- 1433-2965. ; 29:Suppl. 1, s. S491-S491
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Objectives: Gastric bypass surgery constitutes the most common and effective bariatric surgery to treat obesity. Gastric bypass leads to bone oss but fracture risk following surgery has been insufficiently studied. Our objective was to investigate if gastric bypass surgery in obese patients, with and without diabetes, was associated with fracture risk, and if the fracture risk was associated with post-surgery weight loss or insufficient calcium and vitamin D supplementation.Methods: Using large databases, 38 971 obese patients undergoing gastric bypass were identified, 7758 with diabetes and 31 213 without. Through multivariable 1:1 propensity score matching, well-balanced controls were identified. The risk of fracture and fall injury was investigated using Cox proportional hazards and flexible parameter models. Fracture risk according to weight loss and degree of calcium and vitamin D supplementation one year post-surgery was investigated.Results: 77 942 patients had a median and total follow-up time of 3.1 (IQR 1.7-4.6) and 251 310 person-years, respectively. Gastric bypass was associated with increased risk of any fracture, in patients with diabetes and without diabetes using a multivariable Cox model (HR 1.26, 95%CI 1.05-1.53 and HR 1.32, 95%CI 1.18-1.47, respectively). The risk of fall injury without fracture was also increased after gastric bypass, both in patients with (HR 1.26 95%CI 1.04-1.52) and without diabetes (HR 1.24 95%CI 1.12-1.38). Weight loss or degree of calcium and vitamin D supplementation after gastric bypass were not associated with fracture risk.Conclusions: Gastric bypass was associated with an increased risk of fracture and fall injury. Weight loss or calcium and vitamin D supplementation following surgery were not associated with fracture risk. These findings indicate that gastric bypass increases fracture risk, which could at least partly be due to increased susceptibility to falls.
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| 11. |
- Bondesson, Johan, 1991, et al.
(författare)
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Definition of Tubular Anatomic Structures from Arbitrary Stereo Lithographic Surface
- 2017
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Ingår i: Initiative Seminar Engineering Health, 8-9 November 2017, Chalmers.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An accurate description of anatomies and dynamics of vessels is crucial to understand their characteristics and improve surgical techniques, thus it is the basis, in addition to surgeon experience, on which stent design and operation procedures rely. The process of producing this description is user intensive, and recent improvement in image processing of medical3D imaging allows for a more automated workflow. However, there is a need to bridge the gap from a processed geometry to a robust mathematical computational grid. By sequentially segmenting a tubular anatomic structure, here defined by a stereo lithographic (STL) surface, an initial centerline is formed by connecting centroids of orthogonal cross-sectional contours along the length of the structure. Relying on the initial centerline, a set of non-overlapping 2D cross sectional contours are defined along the centerline, a centerline which is updated after the 2D contours are produced. After a second iteration of producing 2D contours and updating the centerline, a full description of the structure is created. Our method for describing vessel geometry shows good coherence to existing method. The main advantages of our method include the possibility of having arbitrary triangulated STL surface input, automated centerline definition, safety against intersecting cross-sectional contours and automatic clean-up of local kinks and wrinkles.
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| 12. |
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| 13. |
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| 14. |
- Giuffrida, L., et al.
(författare)
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Manipulation of laser-accelerated proton beam profiles by nanostructured and microstructured targets
- 2017
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Ingår i: Physical Review Accelerators and Beams. - 2469-9888. ; 20:8, s. 081301-
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Tidskriftsartikel (refereegranskat)abstract
- Nanostructured and microstructured thin foils have been fabricated and used experimentally as targets to manipulate the spatial profile of proton bunches accelerated through the interaction with high intensity laser pulses (6 x 1019 W/cm(2)). Monolayers of polystyrene nanospheres were placed on the rear surfaces of thin plastic targets to improve the spatial homogeneity of the accelerated proton beams. Moreover, thin targets with grating structures of various configurations on their rear sides were used tomodify the proton beam divergence. Experimental results are presented, discussed, and supported by 3D particle-in-cell numerical simulations.
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| 15. |
- Šmíd, M., et al.
(författare)
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Highly efficient angularly resolving x-ray spectrometer optimized for absorption measurements with collimated sources
- 2017
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 88:6
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Tidskriftsartikel (refereegranskat)abstract
- Highly collimated betatron radiation from a laser wakefield accelerator is a promising tool for spectroscopic measurements. Therefore, there is a requirement to create spectrometers suited to the unique properties of such a source. We demonstrate a spectrometer which achieves an energy resolution of <5 eV at 9 keV (E/Delta;E>1800) and is angularly resolving the x-ray emission allowing the reference and spectrum to be recorded at the same time. The single photon analysis is used to significantly reduce the background noise. Theoretical performance of various configurations of the spectrometer is calculated by a ray-tracing algorithm. The properties and performance of the spectrometer including the angular and spectral resolution are demonstrated experimentally on absorption above the K-edge of a Cu foil backlit by a laser-produced betatron radiation x-ray beam.
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| 18. |
- Willermark, Sara, 1988-
(författare)
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Digital Didaktisk Design : Att utveckla undervisning i och för en digitaliserad skola
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- I denna avhandling undersöks grundskollärares arbete med att utveckla sin undervisningspraktik med digital teknik. Mer precist undersöks hur en sådan utveckling kan identifieras, förstås och stödjas. Empirin härstammar primärt från ett treårigt aktionsorienterat skolutvecklingsprojekt i nordisk grundskola. Inom projektet samarbetade lärare från Sverige, Norge och Danmark för att utveckla nya undervisningsaktiviteter över nationsgränserna med stöd av digital teknik. Lärare organiserades inom olika ämnesspecifika designteam för att planera, implementera och utvärdera undervisningsaktiviteter, så kallad digital didaktisk design, vilket avser utformandet av en undervisningssekvens, som adresserar ett specifikt ämne inom ett visst ämnesområde. Det empiriska underlaget utgörs av dokumentation över den digitala didaktiska designen, deltagande observationer, intervjuer och innehållsanalyser samt en enkätundersökning. Två teoretiska ramverk används, TPACK (akronym för Technological Pedagogical And Content Knowledge) och verksamhetsteori. Resultaten påvisar en utveckling av lärares undervisningspraktik. Med stöd av digital teknik skapar lärare digital didaktisk design över nationsgränser, som ger upphov till nya aktiviteter, situationer och möten. Det krävdes dock både omfattande arbetsinsatser och ett praktiskt experimenterande under lång tid, för att lärarna skulle kunna utveckla digital didaktisk design som upplevdes meningsfull i den nya kontexten. Motsättningar och organisatoriska gränser mellan de samverkande lärarna identifierades som avgörande för utvecklingen, genom att ge upphov till förhandlingar, kompromisser och reflektion. Avhandlingen bidrar med ett verktyg för att identifiera och stödja lärares arbetemed att utveckla sin undervisningspraktik med digital teknik. Vidare föreslås en strategi för att identifiera och analysera lärares utveckling över tid. Avhandlingen bidrar också med kunskap om hur olika typer av spänningar och gränser vid samarbete kan stimulera till lärande för en digitaliserad undervisningspraktik, liksom rekommendationer för hur utbildningsinsatser för lärare kan utformas i syfte att stödja lärares utveckling av undervisningspraktiken.
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