| 1. |
- Abdelhameed, A. H., et al.
(author)
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Cryogenic characterization of a LiAlO2 crystal and new results on spin-dependent dark matter interactions with ordinary matter: CRESST Collaboration
- 2020
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 80:9
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Journal article (peer-reviewed)abstract
- In this work, a first cryogenic characterization of a scintillating LiAlO2 single crystal is presented. The results achieved show that this material holds great potential as a target for direct dark matter search experiments. Three different detector modules obtained from one crystal grown at the Leibniz-Institut fur Kristallzuchtung (IKZ) have been tested to study different properties at cryogenic temperatures. Firstly, two 2.8 g twin crystals were used to build different detector modules which were operated in an above-ground laboratory at the Max Planck Institute for Physics (MPP) in Munich, Germany. The first detector module was used to study the scintillation properties of LiAlO2 at cryogenic temperatures. The second achieved an energy threshold of (213.02 +/- 1.48) eV which allows setting a competitive limit on the spin-dependent dark matter particle-proton scattering cross section for dark matter particle masses between 350 MeV/c2 and 1.50 GeV/c2. Secondly, a detector module with a 373 g LiAlO2 crystal as the main absorber was tested in an underground facility at the Laboratori Nazionali del Gran Sasso (LNGS): from this measurement it was possible to determine the radiopurity of the crystal and study the feasibility of using this material as a neutron flux monitor for low-background experiments.
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| 2. |
- Abdelhameed, A. H., et al.
(author)
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First results on sub-GeV spin-dependent dark matter interactions with Li-7
- 2019
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 79:7
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Journal article (peer-reviewed)abstract
- In this work, we want to highlight the potential of lithium as a target for spin-dependent dark matter search in cryogenic experiments, with a special focus on the low-mass region of the parameter space. We operated a prototype detector module based on a Li2MoO4 target crystal in an above-ground laboratory. Despite the high background environment, the detector sets a competitive limit on spin-dependent interactions of dark matter particles with protons and neutrons for masses between 1.5 GeV/c(2).
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| 3. |
- Angloher, G., et al.
(author)
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Limits on dark matter effective field theory parameters with CRESST-II
- 2019
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 79:1
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Journal article (peer-reviewed)abstract
- CRESST is a direct dark matter search experiment, aiming for an observation of nuclear recoils induced by the interaction of dark matter particles with cryogenic scintillating calcium tungstate crystals. Instead of confining ourselves to standard spin-independent and spin-dependent searches, we re-analyze data from CRESST-II using a more general effective field theory (EFT) framework. On many of the EFT coupling constants, improved exclusion limits in the low-mass region (< 3–4 GeV/c2) are presented.
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| 4. |
- Bertoldo, E., et al.
(author)
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Lithium-Containing Crystals for Light Dark Matter Search Experiments
- 2020
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In: Journal of Low Temperature Physics. - : Springer Science and Business Media LLC. - 0022-2291 .- 1573-7357. ; 199:1-2, s. 510-518
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Journal article (peer-reviewed)abstract
- In the current direct dark matter search landscape, the leading experiments in the sub-GeV mass region mostly rely on cryogenic techniques which employ crystalline targets. One attractive type of crystals for these experiments is those containing lithium, due to the fact that 7Li is an ideal candidate to study spin-dependent dark matter interactions in the low mass region. Furthermore, 6Li can absorb neutrons, a challenging background for dark matter experiments, through a distinctive signature which allows the monitoring of the neutron flux directly on site. In this work, we show the results obtained with three different detectors based on LiAlO 2, a target crystal never used before in cryogenic experiments.
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| 5. |
- Abdelhameed, A. H., et al.
(author)
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Geant4-based electromagnetic background model for the CRESST dark matter experiment
- 2019
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In: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 79:10
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Journal article (peer-reviewed)abstract
- The CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) dark matter search experiment aims for the detection of dark matter particles via elastic scattering off nuclei in CaWO4 crystals. To understand the CRESST electromagnetic background due to the bulk contamination in the employed materials, a model based on Monte Carlo simulations was developed using the Geant4 simulation toolkit. The results of the simulation are applied to the TUM40 detector module of CRESST-II phase 2. We are able to explain up to (68 +/- 16)% of the electromagnetic background in the energy range between 1 and 40 keV.
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| 6. |
- Kluck, H., et al.
(author)
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Latest results of CRESST-III's search for sub-GeV/c(2) dark matter
- 2020
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In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 1468:1
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Conference paper (peer-reviewed)abstract
- The CRESST-III experiment searches for direct interactions of dark matter with ordinary matter. The main event signature would be a nuclear recoil inside one of the scintillating CaWO4 crystals. Operating the crystals as cryogenic calorimeters provides a phonon signal as measure of the deposited energy. The simultaneous readout of both signals is used to actively discriminate backgrounds. CRESST-III focuses on the sub-GeV/c(2) mass region where the sensitivity is driven by the threshold. In the first data taking campaign of CRESST-III from 2016-2018 an unprecedented low threshold of 30.1 eV for nuclear recoils was obtained. In this contribution, we will report the status of the experiment and the latest results. [GRAPHICS]
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| 7. |
- Mancuso, M., et al.
(author)
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Searches for Light Dark Matter with the CRESST-III Experiment
- 2020
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In: Journal of Low Temperature Physics. - : Springer Science and Business Media LLC. - 0022-2291 .- 1573-7357. ; 199:1-2, s. 547-555
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Journal article (peer-reviewed)abstract
- Cryogenic Rare Event Search with Superconducting Thermometers (CRESST) is a long-standing direct dark matter detection experiment with cryogenic detectors located at the underground facility Laboratori Nazionali del Gran Sasso in Italy. CRESST-III, the third generation of CRESST, was specifically designed to have a world-leading sensitivity for low-mass dark matter (DM) (less than 2 GeV/c 2) to probe the spin-independent DM-nucleus cross section. At present, a large part of the parameter space for spin-independent scattering off nuclei remains untested for dark matter particles with masses below few GeV/c 2 although many motivated theoretical models having been proposed. The CRESST-III experiment employs scintillating CaWO 4 crystals of ∼ 25 g as target material for dark matter interactions operated as cryogenic scintillating calorimeters at ∼ 10 mK. CRESST-III first data taking was successfully completed in 2018, achieving an unprecedented energy threshold for nuclear recoils. This result extended the present sensitivity to DM particles as light as ∼ 160 MeV/c 2. In this paper, an overview of the CRESST-III detectors and results will be presented.
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| 8. |
- Abdelhameed, A. H., et al.
(author)
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First results from the CRESST-III low-mass dark matter program
- 2019
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 100:10
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Journal article (peer-reviewed)abstract
- The CRESST experiment is a direct dark matter search which aims to measure interactions of potential dark matter particles in an Earth-bound detector. With the current stage, CRESST-III, we focus on a low energy threshold for increased sensitivity towards light dark matter particles. In this paper we describe the analysis of one detector operated in the first run of CRESST-III (05/2016-02/2018) achieving a nuclear recoil threshold of 30.1 eV. This result was obtained with a 23.6 g CaWO4 crystal operated as a cryogenic scintillating calorimeter in the CRESST setup at the Laboratori Nazionali del Gran Sasso (LNGS). Both the primary phonon (heat) signal and the simultaneously emitted scintillation light, which is absorbed in a separate silicon-on-sapphire light absorber, are measured with highly sensitive transition edge sensors operated at similar to 15 mK. The unique combination of these sensors with the light element oxygen present in our target yields sensitivity to dark matter particle masses as low as 160 MeV/c(2).
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| 9. |
- Angloher, G., et al.
(author)
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COSINUS: Cryogenic Calorimeters for the Direct Dark Matter Search with NaI Crystals
- 2020
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In: Journal of Low Temperature Physics. - : Springer Science and Business Media LLC. - 0022-2291 .- 1573-7357. ; 200:5-6, s. 428-436
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Journal article (peer-reviewed)abstract
- COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches) is an experiment employing cryogenic calorimeters, dedicated to direct dark matter search in underground laboratories. Its goal is to cross-check the annual modulation signal the DAMA collaboration has been detecting for about 20 years (Bernabei et al. in Nucl Part Phys Proc 303-305:74-79, 2018. 10.1016/j.nuclphysbps.2019.03.015) and which has been ruled out by other experiments in certain dark matter scenarios. COSINUS can provide a model-independent test by the use of the same target material (NaI), with the additional chance of discriminating beta/gamma events from nuclear recoils on an event-by-event basis, by the application of a well-established temperature sensor technology developed within the CRESST collaboration. Each module is constituted by two detectors: the light detector, that is a silicon beaker equipped with a transition edge sensor (TES), and the phonon detector, a small cubic NaI crystal interfaced with a carrier of a harder material (e.g. CdWO4), also instrumented with a TES. This technology had so far never been applied to NaI crystals because of several well-known obstacles, and COSINUS is the first experiment which succeeded in operating NaI crystals as cryogenic calorimeters. Here, we present the COSINUS project, describe the achievements and the challenges of the COSINUS prototype development and discuss the status and the perspectives of this NaI-based cryogenic frontier.
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| 10. |
- Basset, F. Basso, et al.
(author)
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Entanglement Swapping with Photons Generated on Demand by a Quantum Dot
- 2019
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In: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 123:16
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Journal article (peer-reviewed)abstract
- Photonic entanglement swapping, the procedure of entangling photons without any direct interaction, is a fundamental test of quantum mechanics and an essential resource to the realization of quantum networks. Probabilistic sources of nonclassical light were used for seminal demonstration of entanglement swapping, but applications in quantum technologies demand push-button operation requiring single quantum emitters. This, however, turned out to be an extraordinary challenge due to the stringent prerequisites on the efficiency and purity of the generation of entangled states. Here we show a proof-of-concept demonstration of all-photonic entanglement swapping with pairs of polarization-entangled photons generated on demand by a GaAs quantum dot without spectral and temporal filtering. Moreover, we develop a theoretical model that quantitatively reproduces the experimental data and provides insights on the critical figures of merit for the performance of the swapping operation. Our theoretical analysis also indicates how to improve stateof-the-art entangled-photon sources to meet the requirements needed for implementation of quantum dots in long-distance quantum communication protocols.
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| 11. |
- Gneiss, C, et al.
(author)
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Comparative study of four different assays for the detection of binding antibodies against interferon-beta
- 2008
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In: Multiple sclerosis (Houndmills, Basingstoke, England). - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 14:6, s. 830-836
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Journal article (peer-reviewed)abstract
- Background Binding antibodies (BAB) against interferon-β (IFNβ) are often determined as screening assays before performing an expensive and elaborate neutralizing antibody (NAB) test. Methods In this study, we compared four BAB tests, a western blot (WB), a direct binding enzyme-linked immunosorbent assay (ELISA) (dELISA), a capture ELISA (cELISA), and a commercial enzyme immuno-assay (EIA) in 325 multiple sclerosis patients with and without neutralizing antibodies to evaluate the sensitivity and specificity to detect NAB by receiver operating characteristics analysis. Results The area under the curve (AUC) values were 0.907 for the dELISA, 0.925 for the cELISA, and 0.776 for the EIA ( P < 0.0001 for all). At a sensitivity of 95%, the specificity was approximately 30% in the dELISA, 55% in the cELISA, and 13% in the EIA. The WB as a qualitative BAB detection method had a given sensitivity of 97% and a specificity of 55%. There was a strong and significant correlation between high NAB titers (>500 neutralizing units [NU]) and titers obtained by all quantitative BAB assays. However, low to medium NAB titers (20–500 NU) did not significantly correlate with BAB titers. Conclusion We conclude that the cELISA seems to be most suitable for NAB screening, but BAB titers cannot reliably predict NAB titers.
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| 12. |
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| 13. |
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| 14. |
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| 15. |
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| 16. |
- Heinzel, Andreas, et al.
(author)
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Validation of Plasma Biomarker Candidates for the Prediction of eGFR Decline in Patients With Type 2 Diabetes
- 2018
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In: Diabetes Care. - : American Diabetes Association. - 1935-5548 .- 0149-5992. ; 41:9, s. 1947-1954
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Journal article (peer-reviewed)abstract
- RESEARCH DESIGN AND METHODS: We studied participants in PROVALID (PROspective cohort study in patients with type 2 diabetes mellitus for VALIDation of biomarkers), a prospective multinational cohort study of patients with type 2 diabetes and a follow-up of more than 24 months (n = 2,560; baseline median eGFR, 84 mL/min/1.73 m2; urine albumin-to-creatinine ratio, 8.1 mg/g). The 17 biomarkers were measured at baseline in 481 samples using Luminex and ELISA. The prediction of eGFR decline was evaluated by linear mixed modeling.RESULTS: In univariable analyses, 9 of the 17 markers showed significant differences in median concentration between stable and fast-progressing patients. A linear mixed model for eGFR obtained by variable selection exhibited an adjusted R2 of 62%. A panel of 12 biomarkers was selected by the procedure and accounted for 34% of the total explained variability, of which 32% was due to 5 markers. The individual contribution of each biomarker to the prediction of eGFR decline on top of clinical predictors was generally low. When included into the model, baseline eGFR exhibited the largest explained variability of eGFR decline (R2 of 79%), and the contribution of each biomarker dropped below 1%.CONCLUSIONS: In this longitudinal study of patients with type 2 diabetes and maintained eGFR at baseline, 12 of the 17 candidate biomarkers were associated with eGFR decline, but their predictive power was low.OBJECTIVE: The decline of estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes is variable, and early interventions would likely be cost-effective. We elucidated the contribution of 17 plasma biomarkers to the prediction of eGFR loss on top of clinical risk factors.
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| 17. |
- Saracino, S., et al.
(author)
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A closer look at the binary content of NGC 1850
- 2023
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In: Monthly notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 526:1, s. 299-322
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Journal article (peer-reviewed)abstract
- Studies of young clusters have shown that a large fraction of O-/early B-type stars are in binary systems, where the binary fraction increases with mass. These massive stars are present in clusters of a few Myr, but gradually disappear for older clusters. The lack of detailed studies of intermediate-age clusters has meant that almost no information is available on the multiplicity properties of stars with M < 4M⊙. In this study we present the first characterization of the binary content of NGC 1850, a 100 Myr-old massive star cluster in the Large Magellanic Cloud, relying on a VLT/MUSE multi-epoch spectroscopic campaign. By sampling stars down to M = 2.5 M⊙, we derive a close binary fraction of 24 ± 5 per cent in NGC 1850, in good agreement with the multiplicity frequency predicted for stars of this mass range. We also find a trend with stellar mass (magnitude), with higher mass (brighter) stars having higher binary fractions. We modelled the radial velocity curves of individual binaries using THE JOKER and constrained the orbital properties of 27 systems, ∼17 per cent of all binaries with reliable radial velocities in NGC 1850. This study has brought to light a number of interesting objects, such as four binaries showing mass functions f(M) > 1.25 M⊙. One of these, star #47, has a peculiar spectrum, explainable with the presence of two discs in the system, around the visible star and the dark companion, which is a black hole candidate. These results confirm the importance and urgency of studying the binary content of clusters of any age.
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| 18. |
- Stefanova, N, et al.
(author)
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Ultrastructure of alpha-synuclein-positive aggregations in U373 astrocytoma and rat primary glial cells
- 2002
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In: Neuroscience Letters. - 0304-3940. ; 323:1, s. 37-40
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Journal article (peer-reviewed)abstract
- Abnormal alpha-synuclein-positive glial cytoplasmic inclusions are found in Parkinson's disease, multiple system atrophy and dementia with Lewy bodies. We have recently developed an in vitro model of alpha-synuclein-immunoreactive aggregations in U373 astrocytoma cells. We have additionally overexpressed wild-type and a C-terminally truncated form of alpha-synuclein in primary rat glial cells. Astrocytes and oligodendrocytes were found to form alpha-synuclein-positive aggregations in vitro perinuclearly or in the processes of the cells. The morphological studies presented here demonstrate that the aggregations we have observed in vitro are not limited by a membrane but have unclear borders. They have an amorphous dense core that is intensely alpha-synuclein-immunopositive and a predominantly filamentous halo around. Mainly filamentous structures at the border area between the halo and the core are alpha-synuclein-immunoreactive. We conclude that this in vitro model of alpha-synuclein-positive glial aggregations mimics the morphology of the abnormal glial inclusions described in neuroclegenerative disorders and could be a suitable model for studying their role in the pathogenesis of these diseases. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.
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| 19. |
- Storm, Petter, et al.
(author)
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Conserved features of cancer cells define their sensitivity to HAMLET-induced death; c-Myc and glycolysis.
- 2011
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In: Oncogene. - : Springer Science and Business Media LLC. - 1476-5594 .- 0950-9232. ; 30, s. 4765-4779
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Journal article (peer-reviewed)abstract
- HAMLET is the first member of a new family of tumoricidal protein-lipid complexes that kill cancer cells broadly, while sparing healthy, differentiated cells. Many and diverse tumor cell types are sensitive to the lethal effect, suggesting that HAMLET identifies and activates conserved death pathways in cancer cells. Here, we investigated the molecular basis for the difference in sensitivity between cancer cells and healthy cells. Using a combination of small-hairpin RNA (shRNA) inhibition, proteomic and metabolomic technology, we identified the c-Myc oncogene as one essential determinant of HAMLET sensitivity. Increased c-Myc expression levels promoted sensitivity to HAMLET and shRNA knockdown of c-Myc suppressed the lethal response, suggesting that oncogenic transformation with c-Myc creates a HAMLET-sensitive phenotype. Furthermore, HAMLET sensitivity was modified by the glycolytic state of tumor cells. Glucose deprivation sensitized tumor cells to HAMLET-induced cell death and in the shRNA screen, hexokinase 1 (HK1), 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 1 and hypoxia-inducible factor 1α modified HAMLET sensitivity. HK1 was shown to bind HAMLET in a protein array containing ∼8000 targets, and HK activity decreased within 15 min of HAMLET treatment, before morphological signs of tumor cell death. In parallel, HAMLET triggered rapid metabolic paralysis in carcinoma cells. Tumor cells were also shown to contain large amounts of oleic acid and its derivatives already after 15 min. The results identify HAMLET as a novel anti-cancer agent that kills tumor cells by exploiting unifying features of cancer cells such as oncogene addiction or the Warburg effect.
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