1. |
- Paraschos, Georgios Filippos, et al.
(författare)
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Ordered magnetic fields around the 3C 84 central black hole
- 2024
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 682
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Tidskriftsartikel (refereegranskat)abstract
- Context . 3C 84 is a nearby radio source with a complex total intensity structure, showing linear polarisation and spectral patterns. A detailed investigation of the central engine region necessitates the use of very-long-baseline interferometry (VLBI) above the hitherto available maximum frequency of 86 GHz. Aims. Using ultrahigh resolution VLBI observations at the currently highest available frequency of 228 GHz, we aim to perform a direct detection of compact structures and understand the physical conditions in the compact region of 3C 84. Methods . We used Event Horizon Telescope (EHT) 228 GHz observations and, given the limited (u, v)-coverage, applied geometric model fitting to the data. Furthermore, we employed quasi-simultaneously observed, ancillary multi-frequency VLBI data for the source in order to carry out a comprehensive analysis of the core structure. Results . We report the detection of a highly ordered, strong magnetic field around the central, supermassive black hole of 3C 84. The brightness temperature analysis suggests that the system is in equipartition. We also determined a turnover frequency of νm = (113 ± 4) GHz, a corresponding synchrotron self-absorbed magnetic field of BSSA = (2.9 ± 1.6) G, and an equipartition magnetic field of Beq = (5.2 ± 0.6) G. Three components are resolved with the highest fractional polarisation detected for this object (mnet = (17.0 ± 3.9)%). The positions of the components are compatible with those seen in low-frequency VLBI observations since 2017-2018. We report a steeply negative slope of the spectrum at 228 GHz. We used these findings to test existing models of jet formation, propagation, and Faraday rotation in 3C 84. Conclusions . The findings of our investigation into different flow geometries and black hole spins support an advection-dominated accretion flow in a magnetically arrested state around a rapidly rotating supermassive black hole as a model of the jet-launching system in the core of 3C 84. However, systematic uncertainties due to the limited (u, v)-coverage, however, cannot be ignored. Our upcoming work using new EHT data, which offer full imaging capabilities, will shed more light on the compact region of 3C 84.
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2. |
- Röder, M., et al.
(författare)
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Coulomb dissociation of 20,21 N
- 2016
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813. ; 93:6
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Tidskriftsartikel (refereegranskat)abstract
- Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N20,21 are reported. Relativistic N20,21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the N19(n,γ)N20 and N20(n,γ)N21 excitation functions and thermonuclear reaction rates have been determined. The N19(n,γ)N20 rate is up to a factor of 5 higher at T
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3. |
- Altstadt, S.G., et al.
(författare)
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B-13,B-14(n,gamma) via Coulomb Dissociation for Nucleosynthesis towards the r-Process
- 2014
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Ingår i: Nuclear Data Sheets. - : Elsevier BV. - 1095-9904 .- 0090-3752. ; 120, s. 197-200
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Konferensbidrag (refereegranskat)abstract
- Radioactive beams of 14,15B produced by fragmentation of a primary 40Ar beam were directed onto a Pb target to investigate the neutron breakup within the Coulomb field. The experiment was performed at the LAND/R3B setup. Preliminary results for the Coulomb dissociation cross sections as well as for the astrophysically interesting inverse reactions, 13,14B(n,γ), are presented.
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4. |
- Thies, Ronja, 1987, et al.
(författare)
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Systematic investigation of projectile fragmentation using beams of unstable B and C isotopes
- 2016
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813. ; 93:5
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Tidskriftsartikel (refereegranskat)abstract
- Models describing nuclear fragmentation and fragmentation fission deliver important input for planning nuclear physics experiments and future radioactive ion beam facilities. These models are usually benchmarked against data from stable beam experiments. In the future, two-step fragmentation reactions with exotic nuclei as stepping stones are a promising tool for reaching the most neutron-rich nuclei, creating a need for models to describe also these reactions. Purpose: We want to extend the presently available data on fragmentation reactions towards the light exotic region on the nuclear chart. Furthermore, we want to improve the understanding of projectile fragmentation especially for unstable isotopes. Method: We have measured projectile fragments from C10,12-18 and B10-15 isotopes colliding with a carbon target. These measurements were all performed within one experiment, which gives rise to a very consistent data set. We compare our data to model calculations. Results: One-proton removal cross sections with different final neutron numbers (1pxn) for relativistic C10,12-18 and B10-15 isotopes impinging on a carbon target. Comparing model calculations to the data, we find that the epax code is not able to describe the data satisfactorily. Using abrabla07 on the other hand, we find that the average excitation energy per abraded nucleon needs to be decreased from 27 MeV to 8.1 MeV. With that decrease abrabla07 describes the data surprisingly well. Conclusions: Extending the available data towards light unstable nuclei with a consistent set of new data has allowed a systematic investigation of the role of the excitation energy induced in projectile fragmentation. Most striking is the apparent mass dependence of the average excitation energy per abraded nucleon. Nevertheless, this parameter, which has been related to final-state interactions, requires further study.
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5. |
- Boillos, J. M., et al.
(författare)
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Isotopic cross sections of fragmentation residues produced by light projectiles on carbon near
- 2022
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Ingår i: Physical Review C. - 2469-9993 .- 2469-9985. ; 105:1
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Tidskriftsartikel (refereegranskat)abstract
- We measured 135 cross sections of residual nuclei produced in fragmentation reactions of C12, N14, and O13−16,20,22 projectiles impinging on a carbon target at kinetic energies of near 400A MeV, most of them for the first time, with the RB3/LAND setup at the GSI facility in Darmstadt (Germany). The use of this state-of-the-art experimental setup in combination with the inverse kinematics technique gave the full identification in atomic and mass numbers of fragmentation residues with a high precision. The cross sections of these residues were determined with uncertainties below 20% for most of the cases. These data are compared to other previous measurements with stable isotopes and are also used to benchmark different model calculations.
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6. |
- Revel, A., et al.
(författare)
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Strong Neutron Pairing in core+4n Nuclei
- 2018
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 120:15
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Tidskriftsartikel (refereegranskat)abstract
- The emission of neutron pairs from the neutron-rich N=12 isotones C18 and O20 has been studied by high-energy nucleon knockout from N19 and O21 secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment-n-n correlations shows that the decay N19(-1p)C18∗→C16+n+n is clearly dominated by direct pair emission. The two-neutron correlation strength, the largest ever observed, suggests the predominance of a C14 core surrounded by four valence neutrons arranged in strongly correlated pairs. On the other hand, a significant competition of a sequential branch is found in the decay O21(-1n)O20∗→O18+n+n, attributed to its formation through the knockout of a deeply bound neutron that breaks the O16 core and reduces the number of pairs.
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7. |
- Atar, L., et al.
(författare)
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Quasifree (p, 2p) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength
- 2018
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 120:5
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Tidskriftsartikel (refereegranskat)abstract
- Quasifree one-proton knockout reactions have been employed in inverse kinematics for a systematic study of the structure of stable and exotic oxygen isotopes at the R3B/LAND setup with incident beam energies in the range of 300-450 MeV/u. The oxygen isotopic chain offers a large variation of separation energies that allows for a quantitative understanding of single-particle strength with changing isospin asymmetry. Quasifree knockout reactions provide a complementary approach to intermediate-energy one-nucleon removal reactions. Inclusive cross sections for quasifree knockout reactions of the type OA(p,2p)NA-1 have been determined and compared to calculations based on the eikonal reaction theory. The reduction factors for the single-particle strength with respect to the independent-particle model were obtained and compared to state-of-the-art ab initio predictions. The results do not show any significant dependence on proton-neutron asymmetry.
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8. |
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9. |
- Blanco, A., et al.
(författare)
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Performance of timing resistive plate chambers with relativistic neutrons from 300 to 1500 MeV
- 2015
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Ingår i: Journal of Instrumentation. - : IOP Publishing. - 1748-0221. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic neutrons produced from a deuteron beam of varying energy (300 to 1500 AMeV) in experiment S406 at GSI, Darmstad, Germany. Each layer, with an active area of about 2000 × 500 mm2, is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C2H2F4 and 10% SF6. The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Measurements of the time of flight jitter of neutrons, in the mentioned energy range, point to a contribution of the resistive plate chamber in the order of 150 ps, independent of the neutron energy.
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10. |
- Boretzky, K., et al.
(författare)
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NeuLAND: The high-resolution neutron time-of-flight spectrometer for R 3 B at FAIR
- 2021
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 1014
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Tidskriftsartikel (refereegranskat)abstract
- NeuLAND (New Large-Area Neutron Detector) is the next-generation neutron detector for the R3B (Reactions with Relativistic Radioactive Beams) experiment at FAIR (Facility for Antiproton and Ion Research). NeuLAND detects neutrons with energies from 100 to 1000 MeV, featuring a high detection efficiency, a high spatial and time resolution, and a large multi-neutron reconstruction efficiency. This is achieved by a highly granular design of organic scintillators: 3000 individual submodules with a size of 5 × 5 × 250 cm3 are arranged in 30 double planes with 100 submodules each, providing an active area of 250 × 250 cm2 and a total depth of 3 m. The spatial resolution due to the granularity together with a time resolution of σt≤ 150 ps ensures high-resolution capabilities. In conjunction with calorimetric properties, a multi-neutron reconstruction efficiency of 50% to 70% for four-neutron events will be achieved, depending on both the emission scenario and the boundary conditions allowed for the reconstruction method. We present in this paper the final design of the detector as well as results from test measurements and simulations on which this design is based.
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11. |
- Machado, J., et al.
(författare)
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Performance of timing Resistive Plate Chambers with protons from 200 to 800 MeV
- 2015
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 10:1, s. C01043-
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Tidskriftsartikel (refereegranskat)abstract
- A prototype composed of four resistive plate chamber layers has been exposed to quasi-monoenergetic protons produced from a deuteron beam of varying energy (200 to 800 AMeV) in experiment S406 at GSI, Darmstadt, Germany. The aim of the experiment is to characterize the response of the prototype to protons in this energy range, which deposit from 1.75 to 6 times more energy than minimum ionizing particles. Each layer, with an active area of about 2000 × 500 mm 2 , is made of modules containing the active gaps, all in multigap construction. Each gap is defined by 0.3 mm nylon mono-filaments positioned between 2.85 mm thick float glass electrodes. The modules are operated in avalanche mode with a non-flammable gas mixture composed of 90% C 2 H 2 F 4 and 10% SF 6 . The signals are readout by a pick-up electrode formed by 15 copper strips (per layer), spaced at a pitch of 30 mm, connected at both sides to timing front end electronics. Results show an uniform efficiency close to 100% along with a timing resolution of around 60 ps on the entire 2000 × 500 mm 2 area.
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12. |
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13. |
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14. |
- Wagner, L., et al.
(författare)
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Astrophysical S factor of the N 14 (p,γ) O 15 reaction at 0.4-1.3 MeV
- 2018
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Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 97:1
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Tidskriftsartikel (refereegranskat)abstract
- The N14(p,γ)O15 reaction is the slowest reaction of the carbon-nitrogen cycle of hydrogen burning and thus determines its rate. The precise knowledge of its rate is required to correctly model hydrogen burning in asymptotic giant branch stars. In addition, it is a necessary ingredient for a possible solution of the solar abundance problem by using the solar N13 and O15 neutrino fluxes as probes of the carbon and nitrogen abundances in the solar core. After the downward revision of its cross section due to a much lower contribution by one particular transition, capture to the ground state in O15, the evaluated total uncertainty is still 8%, in part due to an unsatisfactory knowledge of the excitation function over a wide energy range. The present work reports precise S factor data at twelve energies between 0.357 and 1.292 MeV for the strongest transition, capture to the 6.79-MeV excited state in O15, and at ten energies between 0.479 and 1.202 MeV for the second strongest transition, capture to the ground state in O15. An R-matrix fit is performed to estimate the impact of the new data on astrophysical energies. The recently suggested slight enhancement of the 6.79-MeV transition at low energy could not be confirmed. The present extrapolated zero-energy S factors are S6.79(0)=1.24±0.11 keV b and SGS(0)=0.19±0.05 keV b.
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15. |
- Ingle, R. A., et al.
(författare)
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Carbon K-edge x-ray emission spectroscopy of gas phase ethylenic molecules
- 2022
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Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 55:4
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Tidskriftsartikel (refereegranskat)abstract
- We report on the C K-edge x-ray absorption spectra and the resonant (RXES) and non-resonant (NXES) x-ray emission spectra of ethylene, allene and butadiene in the gas phase. The RXES and NXES show clear differences for the different molecules. Overall both types of spectra are more structured for ethylene and allene, than for butadiene. Using density functional theory–restricted open shell configuration interaction single calculations, we simulate the spectra with remarkable agreement with the experiment. We identify the spectral features as being due to transitions involving localised 1s orbitals. For allene, there are distinct spectral bands that reflect transitions predominantly from either the central or terminal carbon atoms. These results are discussed in the context of ultrafast x-ray studies aimed at detecting the passage through conical intersections in polyatomic molecules.
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16. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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17. |
- Melander, Arne, et al.
(författare)
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Utilisation of antihyperglycaemic drugs in ten European countries: different developments and different levels.
- 2006
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 49:9, s. 2024-2029
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis The aim of this study was to compare developments in the utilisation of antihyperglycaemic drugs (AHGDs) in ten European countries. Subhect and methods Data on the yearly utilisation of insulin and oral AHGDs were collected from public registers in Denmark, Finland, Norway, Sweden, Belgium, England, Germany, Italy, Portugal and Spain, and were expressed as defined daily doses per 1,000 inhabitants per day. Results Total AGHD utilisation increased everywhere, but at different rates and levels. Insulin utilisation doubled in England and Germany, but hardly changed in Belgium, Portugal or Italy. Sulfonylurea utilisation doubled in Spain, England and Denmark but was reduced in Germany and Sweden. Metformin utilisation increased greatly everywhere. There were two- to three-fold differences in AHGD utilisation even between neighbouring countries. In Finland, there were more users of both insulin (+120%) and oral AHGDs (+80%) than in Denmark, and the daily oral AHGD doses were higher. In Denmark and Sweden, AHGD utilisation was equal in subjects aged < 45 years, but in those >= 45 years of age, both insulin and oral AHGD utilisation were twice as high in Sweden. Conclusions/interpretation The ubiquitous increase in AHGD utilisation, particularly metformin, seems logical, considering the increasing prevalence of type 2 diabetes and the results of the UK Prospective Diabetes Study. However, the large differences even between neighbouring countries are more difficult to explain, and suggest different habits and attitudes in terms of screening and management of type 2 diabetes.
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18. |
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19. |
- Anand, Aseem, et al.
(författare)
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Automated Bone Scan Index as a quantitative imaging biomarker in metastatic castration-resistant prostate cancer patients being treated with enzalutamide
- 2016
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Ingår i: EJNMMI Research. - : Springer. - 2191-219X. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Having performed analytical validation studies, we are now assessing the clinical utility of the upgraded automated Bone Scan Index (BSI) in metastatic castration-resistant prostate cancer (mCRPC). In the present study, we retrospectively evaluated the discriminatory strength of the automated BSI in predicting overall survival (OS) in mCRPC patients being treated with enzalutamide.METHODS: Retrospectively, we included patients who received enzalutamide as a clinically approved therapy for mCRPC and had undergone bone scan prior to starting therapy. Automated BSI, prostate-specific antigen (PSA), hemoglobin (HgB), and alkaline phosphatase (ALP) were obtained at baseline. Change in automated BSI and PSA were obtained from patients who have had bone scan at week 12 of treatment follow-up. Automated BSI was obtained using the analytically validated EXINI Bone(BSI) version 2. Kendall's tau (τ) was used to assess the correlation of BSI with other blood-based biomarkers. Concordance index (C-index) was used to evaluate the discriminating strength of automated BSI in predicting OS.RESULTS: Eighty mCRPC patients with baseline bone scans were included in the study. There was a weak correlation of automated BSI with PSA (τ = 0.30), with HgB (τ = -0.17), and with ALP (τ = 0.56). At baseline, the automated BSI was observed to be predictive of OS (C-index 0.72, standard error (SE) 0.03). Adding automated BSI to the blood-based model significantly improved the C-index from 0.67 to 0.72, p = 0.017. Treatment follow-up bone scans were available from 62 patients. Both change in BSI and percent change in PSA were predictive of OS. However, the combined predictive model of percent PSA change and change in automated BSI (C-index 0.77) was significantly higher than that of percent PSA change alone (C-index 0.73), p = 0.041.CONCLUSIONS: The upgraded and analytically validated automated BSI was found to be a strong predictor of OS in mCRPC patients. Additionally, the change in automated BSI demonstrated an additive clinical value to the change in PSA in mCRPC patients being treated with enzalutamide.
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20. |
- Brönnimann, D., et al.
(författare)
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The lay of land: Strontium isotope variability in the dietary catchment of the Late Iron Age proto-urban settlement of Basel-Gasfabrik, Switzerland
- 2018
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Ingår i: Journal of Archaeological Science: Reports. - : Elsevier BV. - 2352-409X. ; 17, s. 279-292
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Tidskriftsartikel (refereegranskat)abstract
- Basel-Gasfabrik (Switzerland) comprises an extensive La Tène (chiefly Lt D, 150–80 BCE) settlement and two associated cemeteries at which strontium (87Sr/86Sr) isotope analysis of human and animal teeth investigated regional and supra-regional contacts. The interpretation of the analytic data, however, requires information on the isotopic baseline values around the site. Using 102 modern vegetation and 9 water samples from 51 localities, this study characterizes the isotopic ratios of the biologically available strontium of geological units and watercourses around Basel and compares these to 28 human infant, 6 pig, and 5 dog teeth from the site. Furthermore, pedological criteria evaluate the suitability of landforms for crop and pasturelands. The 87Sr/86Sr ratios of the environmental samples from geological units in up to 50 km distance varied between 0.70776 and 0.71794. Human infant teeth exhibited much more homogeneous 87Sr/86Sr ratios (0.70847–0.70950), which coincided largely with those of potential arable soils around Basel and indicate targeted exploitation of landscapes for agriculture. The more variable values of the faunal teeth suggest more widely ranging habitats or imports from the site's hinterlands. Two local isotope ranges were defined based on archaeological enamel samples and modern vegetation data from a confined radius around Basel. The study documents the complexity of distinguishing local and non-local individuals in a geologically heterogeneous region as well as the potential of isotope analyses to explore prehistoric land-use patterns.
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21. |
- Flores-Morales, Amilcar, et al.
(författare)
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Proteogenomic characterization of patient-derived xenografts highlights the role of REST in neuroendocrine differentiation of castration-resistant prostate cancer
- 2019
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Ingår i: Clinical Cancer Research. - 1078-0432. ; 25:2, s. 595-608
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: An increasing number of castration-resistant prostate cancer (CRPC) tumors exhibit neuroendocrine (NE) features. NE prostate cancer (NEPC) has poor prognosis, and its development is poorly understood. Experimental Design: We applied mass spectrometry–based proteomics to a unique set of 17 prostate cancer patient–derived xenografts (PDX) to characterize the effects of castration in vivo, and the proteome differences between NEPC and prostate adenocarcinomas. Genome-wide profiling of REST-occupied regions in prostate cancer cells was correlated to the expression changes in vivo to investigate the role of the transcriptional repressor REST in castration-induced NEPC differentiation. Results: An average of 4,881 proteins were identified and quantified from each PDX. Proteins related to neurogenesis, cell-cycle regulation, and DNA repair were found upregulated and elevated in NEPC, while the reduced levels of proteins involved in mitochondrial functions suggested a prevalent glycolytic metabolism of NEPC tumors. Integration of the REST chromatin bound regions with expression changes indicated a direct role of REST in regulating neuronal gene expression in prostate cancer cells. Mechanistically, depletion of REST led to cell-cycle arrest in G1, which could be rescued by p53 knockdown. Finally, the expression of the REST-regulated gene secretagogin (SCGN) correlated with an increased risk of suffering disease relapse after radical prostatectomy. Conclusions: This study presents the first deep characterization of the proteome of NEPC and suggests that concomitant inhibition of REST and the p53 pathway would promote NEPC. We also identify SCGN as a novel prognostic marker in prostate cancer.
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22. |
- Geironson Ulfsson, Linda, et al.
(författare)
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Tapasin facilitation of MHC-I separates closely related allomorphs, is strongly influenced by peptide length and depends on stability
- 2013
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Ingår i: ; , s. 83-83
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Konferensbidrag (refereegranskat)abstract
- Only a small fraction of the peptides inside a cell are eventually presented by HLA-I on the cell surface. The presented peptides have HLA-I allomorph-specific motifs and length restrictions. Tapasin influences HLA-I antigen presentation both qualitatively and quantitatively to different degrees depending on both peptide sequence and HLA-I allomorph. The tapasin-dependence in cellular context has been shown to correspond to the facilitation of peptide- HLA-I complex formation by the first 87 amino acids of tapasin (Tpn1- 87) (i.e., tapasin-facilitation = Bmax Tpn1-87/Bmax Ctrl) in a biochemical assay. Both peptide length and tapasin-facilitation are important for HLA-I antigen presentation and we here set out to study if these two parameters relate to each other. We used a luminescent oxygen channeling assay and seven different peptide libraries (X7- X13) to study 16 HLA-A and -B allomorphs and the results show a broad spectrum of tapasin-facilitation of HLA-I allomorphs and that HLA-A allomorphs were generally less restricted than -B allomorphs83to peptides of the classical lengths of 8-10 amino acids. Since both stability and tapasin-facilitation have been suggested as discriminators of immunogenic peptides we used a scintillation proximity based assay to study the stability of peptide-HLA-I complexes formed with peptides of different lengths. The results demonstrate an inverse correlation between tapasin-facilitation and stability valid for different peptide mixes of specific lengths but also on the level of HLA-I allomorphs, suggesting that molecules of poor stability are either not in a conformation that allows tapasin to interact or have a conformation where association has no effect.
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23. |
- Geironson Ulfsson, Linda, et al.
(författare)
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Tapasin Facilitation of Natural HLA-A and -B Allomorphs Is Strongly Influenced by Peptide Length, Depends on Stability, and Separates Closely Related Allomorphs.
- 2013
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 191:7, s. 3939-3947
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Tidskriftsartikel (refereegranskat)abstract
- Despite an abundance of peptides inside a cell, only a small fraction is ultimately presented by HLA-I on the cell surface. The presented peptides have HLA-I allomorph-specific motifs and are restricted in length. So far, detailed length studies have been limited to few allomorphs. Peptide-HLA-I (pHLA-I) complexes of different allomorphs are qualitatively and quantitatively influenced by tapasin to different degrees, but again, its effect has only been investigated for a small number of HLA-I allomorphs. Although both peptide length and tapasin dependence are known to be important for HLA-I peptide presentation, the relationship between them has never been studied. In this study, we used random peptide libraries from 7- to 13-mers and studied binding in the presence and absence of a recombinant truncated form of tapasin. The data show that HLA-I allomorphs are differentially affected by tapasin, different lengths of peptides generated different amounts of pHLA-I complexes, and HLA-A allomorphs are generally less restricted than HLA-B allomorphs to peptides of the classical length of 8-10 aa. We also demonstrate that tapasin facilitation varies for different peptide lengths, and that the correlation between high degree of tapasin facilitation and low stability is valid for different random peptide mixes of specific lengths. In conclusion, these data show that tapasin has specificity for the combination of peptide length and HLA-I allomorph, and suggest that tapasin promotes formation of pHLA-I complexes with high on and off rates, an important intermediary step in the HLA-I maturation process.
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24. |
- Hendriksen, Rene S., et al.
(författare)
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Global monitoring of antimicrobial resistance based on metagenomics analyses of urban sewage
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- © 2019, The Author(s). Antimicrobial resistance (AMR) is a serious threat to global public health, but obtaining representative data on AMR for healthy human populations is difficult. Here, we use metagenomic analysis of untreated sewage to characterize the bacterial resistome from 79 sites in 60 countries. We find systematic differences in abundance and diversity of AMR genes between Europe/North-America/Oceania and Africa/Asia/South-America. Antimicrobial use data and bacterial taxonomy only explains a minor part of the AMR variation that we observe. We find no evidence for cross-selection between antimicrobial classes, or for effect of air travel between sites. However, AMR gene abundance strongly correlates with socio-economic, health and environmental factors, which we use to predict AMR gene abundances in all countries in the world. Our findings suggest that global AMR gene diversity and abundance vary by region, and that improving sanitation and health could potentially limit the global burden of AMR. We propose metagenomic analysis of sewage as an ethically acceptable and economically feasible approach for continuous global surveillance and prediction of AMR.
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25. |
- Iorio Di, C T, et al.
(författare)
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Cross-border flow of health information: is 'privacy by design' enough? Privacy performance assessment in EUBIROD.
- 2013
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Ingår i: European Journal of Public Health. - : Oxford University Press (OUP). - 1101-1262 .- 1464-360X. ; 23:2, s. 247-53
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Tidskriftsartikel (refereegranskat)abstract
- Background: The EUBIROD project aims to perform a cross-border flow of diabetes information across 19 European countries using the BIRO information system, which embeds privacy principles and data protection mechanisms in its architecture (privacy by design). A specific task of EUBIROD was to investigate the variability in the implementation of the EU Data Protection Directive (DPD) across participating centres. Methods: Compliance with privacy requirements was assessed by means of a specific questionnaire administered to all participating diabetes registers. Items included relevant issues e.g. patient consent, accountability of data custodian, communication (openness) and complaint procedures (challenging compliance), authority to disclose, accuracy, access and use of personal information, and anonymization. The identification of an ad hoc scoring system and statistical software allowed an overall quali-quantitative analysis and independent evaluation of questionnaire responses, automated through a dedicated IT platform (‘privacy performance assessment’). Results: A total of 18 diabetes registers from different countries completed the survey. Over 50% of the registers recorded a maximum score for accountability, openness, anonymization and challenging compliance. Low average values were found for disclosure and disposition, access, consent, use of personal information and accuracy. A high heterogeneity was found for anonymization, consent, accuracy and access. Conclusions: The novel method of privacy performance assessment realized in EUBIROD may improve the respect of privacy in each data source, reduce overall variability in the implementation of privacy principles and favour a sound and legitimate cross-border exchange of high quality data across Europe.
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26. |
- Marston, H. F., et al.
(författare)
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Challenges in the modelling of scale formation and decarburisation of high carbon, special and general steels
- 2004
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Ingår i: Ironmaking & steelmaking. - : Informa UK Limited. - 0301-9233 .- 1743-2812. ; 31:1, s. 57-65
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Tidskriftsartikel (refereegranskat)abstract
- The oxygen bearing gases of the atmosphere in a reheating furnace oxidise the feedstock producing scale on the surface of the metal and, for high carbon steels, cause decarburisation of the surface layers. Modelling of these effects has to take into account the competitive nature of the two processes, scale formation and decarburisation, and complications that arise from changes in the controlling mechanism. Initially, the rate of scale formation may be controlled by effects in the gas phase, or nucleation of scale on the metal surface. Subsequently, scale growth is influenced by the gas composition and may be disturbed by the accumulation of oxidation products at the scale-metal interface. Voids and cracks within the scale may either inhibit solid state diffusion within the scale or provide channels for oxidising gas to access the scale-metal interface, For decarburisation, complications arise if a ferrite rim creates a step in the carbon profile or if retention of carbon monoxide within the scale provides a thermodynamic barrier to the reaction. This paper considers these complications and how they may be handled in mathematical models.
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