| 1. |
- Aderne, Rian E., et al.
(författare)
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On the energy gap determination of organic optoelectronic materials : the case of porphyrin derivatives
- 2022
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Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; :3, s. 1791-1803
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Tidskriftsartikel (refereegranskat)abstract
- The correct determination of the ionization potential (IP) and electron affinity (EA) as well as the energy gap is essential to properly characterize a series of key phenomena related to the applications of organic semiconductors. For example, energy offsets play an essential role in charge separation in organic photovoltaics. Yet there has been a lot of confusion involving the real physical meaning behind those quantities. Experimentally the energy gap can be measured by direct techniques such as UV-Vis absorption, or indirect techniques such as cyclic voltammetry (CV). Another spectroscopic method is the Reflection Electron Energy Loss Spectroscopy (REELS). Regarding data correlation, there is little consensus on how the REELS' energy gap can be interpreted in light of the energies obtained from other methodologies such as CV, UV-Vis, or photoemission. In addition, even data acquired using those traditional techniques has been misinterpreted or applied to derive conclusions beyond the limits imposed by the physics of the measurement. A similar situation also happens when different theoretical approaches are used to assess the energy gap or employed to explain outcomes from experiments. By using a set of porphyrin derivatives as model molecules, we discuss some key aspects of those important issues. The peculiar properties of these porphyrins demonstrate that even straightforward measurements or calculations performed in a group of very similar molecules need a careful interpretation of the outcomes. Differences up to 660 meV (similar to 190 meV) are found comparing REELS (electrochemical) measurements with UV-Vis energy gaps, for instance. From the theoretical point of view, a reasonable agreement with electrochemical measurements of the IP, EA, and the gap of the porphyrins is only obtained when the calculations involve the full thermodynamics of the redox processes. The purpose of this work is to shed light on the differences and similarities of those aforementioned characterization methods and provide some insight that might help one to develop a critical analysis of the different experimental and theoretical methodologies.
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| 2. |
- Bohm, Christian, et al.
(författare)
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A MHz-repetition-rate hard X-ray free-electron laser driven by a superconducting linear accelerator
- 2020
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Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 14:6, s. 391-397
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Tidskriftsartikel (refereegranskat)abstract
- The European XFEL is a hard X-ray free-electron laser (FEL) based on a high-electron-energy superconducting linear accelerator. The superconducting technology allows for the acceleration of many electron bunches within one radio-frequency pulse of the accelerating voltage and, in turn, for the generation of a large number of hard X-ray pulses. We report on the performance of the European XFEL accelerator with up to 5,000 electron bunches per second and demonstrating a full energy of 17.5 GeV. Feedback mechanisms enable stabilization of the electron beam delivery at the FEL undulator in space and time. The measured FEL gain curve at 9.3 keV is in good agreement with predictions for saturated FEL radiation. Hard X-ray lasing was achieved between 7 keV and 14 keV with pulse energies of up to 2.0 mJ. Using the high repetition rate, an FEL beam with 6 W average power was created. The first operation of the European X-ray free-electron laser facility accelerator based on superconducting technology is reported. The maximum electron energy is 17.5 GeV. A laser average power of 6 W is achieved at a photon energy of 9.3 keV.
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| 3. |
- Borgquist, Ola, et al.
(författare)
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Central venous stenosis after subclavian versus internal jugular dialysis catheter insertion (CITES) in adults in need of a temporary central dialysis catheter : study protocol for a two-arm, parallel-group, non-inferiority randomised controlled trial
- 2023
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Ingår i: Trials. - 1745-6215. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The right internal jugular vein is currently recommended for temporary central dialysis catheters (tCDC) based on results from previous studies showing a lower incidence of central vein stenosis compared to the subclavian vein. Data is however conflicting, and there are several advantages when the subclavian route is used for tCDCs. This prospective, controlled, randomised, non-inferiority study aims to compare the incidence of post-catheterisation central vein stenosis between the right subclavian and the right internal jugular routes. Methods: Adult patients needing a tCDC will be included from several hospitals and randomised to either subclavian or internal jugular vein catheterisation with a silicone tCDC. Inclusion continues until 50 patients in each group have undergone a follow-up CT venography. The primary outcome is the incidence of post-catheterisation central vein stenosis detected by a CT venography performed 1.5 to 3 months after removal of the tCDC. Secondary outcomes include between-group comparisons of (I) the patients’ experience of discomfort and pain, (II) any dysfunction of the tCDC during use, (III) catheterisation success rate and (IV) the number of mechanical complications. Furthermore, the ability to detect central vein stenosis by a focused ultrasound examination will be evaluated using the CT venography as golden standard. Discussion: The use of the subclavian route for tCDC placement has largely been abandoned due to older studies with various methodological issues. However, the subclavian route offers several advantages for the patient. This trial is designed to provide robust data on the incidence of central vein stenosis after silicone tCDC insertion in the era of ultrasound-guided catheterisations. Trial registration: Clinicaltrials.gov; NCT04871568. Prospectively registered on May 4, 2021.
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| 4. |
- Falowska-Pietrzak, Olga, 1995-
(författare)
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Absorbed dose and fluence measurements and simulations at EuXFEL undulator systems
- 2023
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The European X-Ray Free Electron Laser generates X-ray pulsesas GeV electrons progress in the beam pipe through periodic arrangements of magnets called undulators. An undesired scattered radiation (stray radiation) is also present outside the beam pipe. It may damage not only undulator magnets, but also diagnostic and correction equipment located near undulators. It results in decreased performance of the EuXFEL. As the severity of magnet damage differs for different particles and energies, it is of great importance to properly characterize the stray radiation field in the vicinity of the undulators. In this thesis, results of Gafchromic film dose measurements near EuXFEL undulators are presented. Films were placed at the entrance of the undulator segments, along the undulator permanent magnets and at the front of phase shifters located in the intersections separating two undulator segments. In addition, Monte Carlo simulations of absorbed dose and fluence were performed with Geant4 toolkit to characterize the composition and energy spectra of the radiation field near undulators. Comparison of film measurements and simulations show that theradiation field near the upstream undulator cells may be a result of high-energy electrons interactions with the beam pipe. Almost 99 % of the dose absorbed to the permanent magnets comes from electrons and positrons created through photon interactions with matter. However, the majority of particles are photons. In addition,simulations show that neutrons are also presented within the magnets. Significant doses were measured further away from thepermanent magnets, close to phase shifters installed in the intersections.
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| 5. |
- Falowska-Pietrzak, Olga, et al.
(författare)
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Investigation of the stray radiation origin and composition at the European XFEL undulators with gafchromic films measurements and Geant4 simulations
- 2023
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 1056
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Tidskriftsartikel (refereegranskat)abstract
- At EuXFEL, a stray field of ionizing radiation is present near undulator magnets which eventually can lead to their demagnetization and decreased efficiency of the Self-Amplified Spontaneous Emission (SASE) process. In this work we investigate both the origin and composition of the radiation field at the undulator magnets with gafchromic film measurements and Geant4 Monte Carlo simulations. Both measurements and simulations suggest that the radiation field in the upstream undulator cells comes from high-energy electrons striking the beam pipe. In addition, horizontal dose distributions at the entrance of the undulator segments depend on where the electrons hit the beam pipe. Geant4 simulations show that the radiation fluence near magnets is dominated by photons, while charged secondary electrons and positrons contribute almost entirely to the ionizing dose absorbed by magnets.
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| 6. |
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| 7. |
- Kumawat, Ashok Kumar, 1982-, et al.
(författare)
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Inhibition of IL17A Using an Affibody Molecule Attenuates Inflammation in ApoE-Deficient Mice
- 2022
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Ingår i: Frontiers in Cardiovascular Medicine. - : Frontiers Media S.A.. - 2297-055X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The balance between pro- and anti-inflammatory cytokines released by immune and non-immune cells plays a decisive role in the progression of atherosclerosis. Interleukin (IL)-17A has been shown to accelerate atherosclerosis. In this study, we investigated the effect on pro-inflammatory mediators and atherosclerosis development of an Affibody molecule that targets IL17A. Affibody molecule neutralizing IL17A, or sham were administered in vitro to human aortic smooth muscle cells (HAoSMCs) and murine NIH/3T3 fibroblasts and in vivo to atherosclerosis-prone, hyperlipidaemic ApoE(-/-) mice. Levels of mediators of inflammation and development of atherosclerosis were compared between treatments. Exposure of human smooth muscle cells and murine NIH/3T3 fibroblasts in vitro to alpha IL-17A Affibody molecule markedly reduced IL6 and CXCL1 release in supernatants compared with sham exposure. Treatment of ApoE(-/-) mice with alpha IL-17A Affibody molecule significantly reduced plasma protein levels of CXCL1, CCL2, CCL3, HGF, PDGFB, MAP2K6, QDPR, and splenocyte mRNA levels of Ccxl1, Il6, and Ccl20 compared with sham exposure. There was no significant difference in atherosclerosis burden between the groups. In conclusion, administration of alpha IL17A Affibody molecule reduced levels of pro-inflammatory mediators and attenuated inflammation in ApoE(-/-) mice.
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| 8. |
- Magnusson, Rasmus, et al.
(författare)
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RNA-sequencing and mass-spectrometry proteomic time-series analysis of T-cell differentiation identified multiple splice variants models that predicted validated protein biomarkers in inflammatory diseases
- 2022
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Ingår i: Frontiers in Molecular Biosciences. - : Frontiers Media SA. - 2296-889X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Profiling of mRNA expression is an important method to identify biomarkers but complicated by limited correlations between mRNA expression and protein abundance. We hypothesised that these correlations could be improved by mathematical models based on measuring splice variants and time delay in protein translation. We characterised time-series of primary human naive CD4(+) T cells during early T helper type 1 differentiation with RNA-sequencing and mass-spectrometry proteomics. We performed computational time-series analysis in this system and in two other key human and murine immune cell types. Linear mathematical mixed time delayed splice variant models were used to predict protein abundances, and the models were validated using out-of-sample predictions. Lastly, we re-analysed RNA-seq datasets to evaluate biomarker discovery in five T-cell associated diseases, further validating the findings for multiple sclerosis (MS) and asthma. The new models significantly out-performing models not including the usage of multiple splice variants and time delays, as shown in cross-validation tests. Our mathematical models provided more differentially expressed proteins between patients and controls in all five diseases. Moreover, analysis of these proteins in asthma and MS supported their relevance. One marker, sCD27, was validated in MS using two independent cohorts for evaluating response to treatment and disease prognosis. In summary, our splice variant and time delay models substantially improved the prediction of protein abundance from mRNA expression in three different immune cell types. The models provided valuable biomarker candidates, which were further validated in MS and asthma.
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| 9. |
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| 10. |
- Tesi, Bianca, et al.
(författare)
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Diagnostic yield and clinical impact of germline sequencing in children with CNS and extracranial solid tumors : a nationwide, prospective Swedish study
- 2024
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Ingår i: The Lancet Regional Health. - : Elsevier. - 2666-7762. ; 39
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundChildhood cancer predisposition (ChiCaP) syndromes are increasingly recognized as contributing factors to childhood cancer development. Yet, due to variable availability of germline testing, many children with ChiCaP might go undetected today. We report results from the nationwide and prospective ChiCaP study that investigated diagnostic yield and clinical impact of integrating germline whole-genome sequencing (gWGS) with tumor sequencing and systematic phenotyping in children with solid tumors.MethodsgWGS was performed in 309 children at diagnosis of CNS (n = 123, 40%) or extracranial (n = 186, 60%) solid tumors and analyzed for disease-causing variants in 189 known cancer predisposing genes. Tumor sequencing data were available for 74% (227/309) of patients. In addition, a standardized clinical assessment for underlying predisposition was performed in 95% (293/309) of patients.FindingsThe prevalence of ChiCaP diagnoses was 11% (35/309), of which 69% (24/35) were unknown at inclusion (diagnostic yield 8%, 24/298). A second-hit and/or relevant mutational signature was observed in 19/21 (90%) tumors with informative data. ChiCaP diagnoses were more prevalent among patients with retinoblastomas (50%, 6/12) and high-grade astrocytomas (37%, 6/16), and in those with non-cancer related features (23%, 20/88), and ≥2 positive ChiCaP criteria (28%, 22/79). ChiCaP diagnoses were autosomal dominant in 80% (28/35) of patients, yet confirmed de novo in 64% (18/28). The 35 ChiCaP findings resulted in tailored surveillance (86%, 30/35) and treatment recommendations (31%, 11/35).InterpretationOverall, our results demonstrate that systematic phenotyping, combined with genomics-based diagnostics of ChiCaP in children with solid tumors is feasible in large-scale clinical practice and critically guides personalized care in a sizable proportion of patients.
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