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- Antel, C., et al.
(author)
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Feebly-interacting particles : FIPs 2022 Workshop Report
- 2023
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In: European Physical Journal C. - : Springer. - 1434-6044 .- 1434-6052. ; 83:12
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Research review (peer-reviewed)abstract
- Particle physics today faces the challenge of explaining the mystery of dark matter, the origin of matter over anti-matter in the Universe, the origin of the neutrino masses, the apparent fine-tuning of the electro-weak scale, and many other aspects of fundamental physics. Perhaps the most striking frontier to emerge in the search for answers involves new physics at mass scales comparable to familiar matter, below the GeV-scale, or even radically below, down to sub-eV scales, and with very feeble interaction strength. New theoretical ideas to address dark matter and other fundamental questions predict such feebly interacting particles (FIPs) at these scales, and indeed, existing data provide numerous hints for such possibility. A vibrant experimental program to discover such physics is under way, guided by a systematic theoretical approach firmly grounded on the underlying principles of the Standard Model. This document represents the report of the FIPs 2022 workshop, held at CERN between the 17 and 21 October 2022 and aims to give an overview of these efforts, their motivations, and the decadal goals that animate the community involved in the search for FIPs.
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| 4. |
- Bianchini, F, et al.
(author)
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Human neutralizing antibodies to cold linear epitopes and subdomain 1 of the SARS-CoV-2 spike glycoprotein
- 2023
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In: Science immunology. - : American Association for the Advancement of Science (AAAS). - 2470-9468. ; 8:81, s. eade0958-
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Journal article (peer-reviewed)abstract
- Emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants diminishes the efficacy of vaccines and antiviral monoclonal antibodies. Continued development of immunotherapies and vaccine immunogens resilient to viral evolution is therefore necessary. Using coldspot-guided antibody discovery, a screening approach that focuses on portions of the virus spike glycoprotein that are both functionally relevant and averse to change, we identified human neutralizing antibodies to highly conserved viral epitopes. Antibody fp.006 binds the fusion peptide and cross-reacts against coronaviruses of the four genera, including the nine human coronaviruses, through recognition of a conserved motif that includes the S2′ site of proteolytic cleavage. Antibody hr2.016 targets the stem helix and neutralizes SARS-CoV-2 variants. Antibody sd1.040 binds to subdomain 1, synergizes with antibody rbd.042 for neutralization, and, similar to fp.006 and hr2.016, protects mice expressing human angiotensin-converting enzyme 2 against infection when present as a bispecific antibody. Thus, coldspot-guided antibody discovery reveals donor-derived neutralizing antibodies that are cross-reactive with Orthocoronavirinae, including SARS-CoV-2 variants.
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| 5. |
- Bianchini, F, et al.
(author)
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Human neutralizing antibodies to cold linear epitopes and subdomain 1 of the SARS-CoV-2 spike glycoprotein
- 2023
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In: Science immunology. - : American Association for the Advancement of Science (AAAS). - 2470-9468. ; 8:81, s. eade0958-
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Journal article (peer-reviewed)abstract
- Emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants diminishes the efficacy of vaccines and antiviral monoclonal antibodies. Continued development of immunotherapies and vaccine immunogens resilient to viral evolution is therefore necessary. Using coldspot-guided antibody discovery, a screening approach that focuses on portions of the virus spike glycoprotein that are both functionally relevant and averse to change, we identified human neutralizing antibodies to highly conserved viral epitopes. Antibody fp.006 binds the fusion peptide and cross-reacts against coronaviruses of the four genera, including the nine human coronaviruses, through recognition of a conserved motif that includes the S2′ site of proteolytic cleavage. Antibody hr2.016 targets the stem helix and neutralizes SARS-CoV-2 variants. Antibody sd1.040 binds to subdomain 1, synergizes with antibody rbd.042 for neutralization, and, similar to fp.006 and hr2.016, protects mice expressing human angiotensin-converting enzyme 2 against infection when present as a bispecific antibody. Thus, coldspot-guided antibody discovery reveals donor-derived neutralizing antibodies that are cross-reactive with Orthocoronavirinae, including SARS-CoV-2 variants.
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| 6. |
- Bianchini, F, et al.
(author)
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Human neutralizing antibodies to cold linear epitopes and to subdomain 1 of SARS-CoV-2
- 2022
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In: bioRxiv : the preprint server for biology. - : Cold Spring Harbor Laboratory.
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Journal article (other academic/artistic)abstract
- Emergence of SARS-CoV-2 variants diminishes the efficacy of vaccines and antiviral monoclonal antibodies. Continued development of immunotherapies and vaccine immunogens resilient to viral evolution is therefore necessary. Using coldspot-guided antibody discovery, a screening approach that focuses on portions of the virus spike that are both functionally relevant and averse to change, we identified human neutralizing antibodies to highly conserved viral epitopes. Antibody fp.006 binds the fusion peptide and cross-reacts against coronaviruses of the fourgenera, including the nine human coronaviruses, through recognition of a conserved motif that includes the S2’ site of proteolytic cleavage. Antibody hr2.016 targets the stem helix and neutralizes SARS-CoV-2 variants. Antibody sd1.040 binds to subdomain 1, synergizes with antibody rbd.042 for neutralization and, like fp.006 and hr2.016, protects mice when present as bispecific antibody. Thus, coldspot-guided antibody discovery reveals donor-derived neutralizing antibodies that are cross-reactive withOrthocoronavirinae, including SARS-CoV-2 variants.Broadly cross-reactive antibodies that protect from SARS-CoV-2 variants are revealed by virus coldspot-driven discovery.
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| 11. |
- Charlton, M., et al.
(author)
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Positron production using a 9 MeV electron linac for the GBAR experiment
- 2021
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In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 985
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Journal article (peer-reviewed)abstract
- For the GBAR (Gravitational Behaviour of Antihydrogen at Rest) experiment at CERN's Antiproton Decelerator (AD) facility we have constructed a source of slow positrons, which uses a low-energy electron linear accelerator (linac). The driver linac produces electrons of 9 MeV kinetic energy that create positrons from bremsstrahlung-induced pair production. Staying below 10 MeV ensures no persistent radioactive activation in the target zone and that the radiation level outside the biological shield is safe for public access. An annealed tungsten-mesh assembly placed directly behind the target acts as a positron moderator. The system produces 5 x 10(7) slow positrons per second, a performance demonstrating that a low-energy electron linac is a superior choice over positron-emitting radioactive sources for high positron flux.
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| 12. |
- Husson, A., et al.
(author)
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A pulsed high-voltage decelerator system to deliver low-energy antiprotons
- 2021
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In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 1002
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Journal article (peer-reviewed)abstract
- The GBAR (Gravitational Behavior of Antihydrogen at Rest) experiment at CERN requires efficient deceleration of 100 keV antiprotons provided by the new ELENA synchrotron ring to synthesize antihydrogen. This is accomplished using electrostatic deceleration optics and a drift tube that is designed to switch from -99 kV to ground when the antiproton bunch is inside – essentially a charged particle “elevator” – producing a 1 keV pulse. We describe the simulation, design, construction and successful testing of the decelerator device at -92 kV on-line with antiprotons from ELENA.
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| 13. |
- Kim, B. H., et al.
(author)
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Development of a PbWO4 Detector for Single-Shot Positron Annihilation Lifetime Spectroscopy at the GBAR Experiment
- 2020
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In: Acta Physica Polonica. A. - 0587-4246 .- 1898-794X. ; 137:2, s. 122-125
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Journal article (peer-reviewed)abstract
- We have developed a PbWO4 (PWO) detector with a large dynamic range to measure the intensity of a positron beam and the absolute density of the ortho-positronium (o-Ps) cloud it creates. A simulation study shows that a setup based on such detectors may be used to determine the angular distribution of the emission and reflection of o-Ps to reduce part of the uncertainties of the measurement. These will allow to improve the precision in the measurement of the cross-section for the (anti)hydrogen formation by (anti)proton-positronium charge exchange and to optimize the yield of antihydrogen ion which is an essential parameter in the GBAR experiment.
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| 14. |
- Niang, S., et al.
(author)
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Accumulation of Positrons from a LINAC Based Source
- 2020
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In: Acta Physica Polonica. A. - 0587-4246 .- 1898-794X. ; 137:2, s. 164-166
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Journal article (peer-reviewed)abstract
- The GBAR experiment aims to measure the gravitational acceleration of antihydrogen (H) over bar. It will use (H) over bar (+) ions formed by the interaction of antiprotons with a dense positronium cloud, which will require about 1010 positrons to produce one (H) over bar (+). We present the first results on the positron accumulation, reaching 3.8 +/- 0.4x10(8) e(+) collected in 560 s.
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| 15. |
- Adrich, P., et al.
(author)
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Production of antihydrogen atoms by 6 keV antiprotons through a positronium cloud
- 2023
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In: European Physical Journal C. - : Springer Nature. - 1434-6044 .- 1434-6052. ; 83:11
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Journal article (peer-reviewed)abstract
- We report on the first production of an antihydrogen beam by charge exchange of 6.1 keV antiprotons with a cloud of positronium in the GBAR experiment at CERN. The 100 keV antiproton beam delivered by the AD/ELENA facility was further decelerated with a pulsed drift tube. A 9 MeV electron beam from a linear accelerator produced a low energy positron beam. The positrons were accumulated in a set of two Penning-Malmberg traps. The positronium target cloud resulted from the conversion of the positrons extracted from the traps. The antiproton beam was steered onto this positronium cloud to produce the antiatoms. We observe an excess over background indicating antihydrogen production with a significance of 3-4 standard deviations.
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| 16. |
- Banerjee, D., et al.
(author)
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Towards a test of the Weak Equivalence Principle of gravity using anti-hydrogen at CERN
- 2016
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In: 2016 Conference On Precision Electromagnetic Measurements (CPEM 2016). - 9781467391344
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Conference paper (peer-reviewed)abstract
- The aim of the GBAR (Gravitational Behavior of Antimatter at Rest) experiment is to measure the free fall acceleration of an antihydrogen atom, in the terrestrial gravitational field at CERN and therefore test the Weak Equivalence Principle with antimatter. The aim is to measure the local gravity with a 1% uncertainty which can be reduced to few parts of 10(-3).
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| 17. |
- Blumer, P., et al.
(author)
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Positron accumulation in the GBAR experiment
- 2022
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In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 1040
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Journal article (peer-reviewed)abstract
- We present a description of the GBAR positron (e+) trapping apparatus, which consists of a three stage Buffer Gas Trap (BGT) followed by a High Field Penning Trap (HFT), and discuss its performance. The overall goal of the GBAR experiment is to measure the acceleration of the neutral antihydrogen (H¯) atom in the terrestrial gravitational field by neutralising a positive antihydrogen ion (H¯+), which has been cooled to a low temperature, and observing the subsequent H¯ annihilation following free fall. To produce one H¯+ ion, about 1010 positrons, efficiently converted into positronium (Ps), together with about 107 antiprotons (p¯), are required. The positrons, produced from an electron linac-based system, are accumulated first in the BGT whereafter they are stacked in the ultra-high vacuum HFT, where we have been able to trap 1.4(2) × 109 positrons in 1100 s.
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| 18. |
- Perez, P., et al.
(author)
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The GBAR antimatter gravity experiment
- 2015
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In: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; , s. 21-27
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Conference paper (peer-reviewed)abstract
- The GBAR project (Gravitational Behaviour of Anti hydrogen at Rest) at CERN, aims to measure the free fall acceleration of ultracold neutral anti hydrogen atoms in the terrestrial gravitational field. The experiment consists preparing anti hydrogen ions (one antiproton and two positrons) and sympathetically cooling them with Be (+) ions to less than 10 mu K. The ultracold ions will then be photo-ionized just above threshold, and the free fall time over a known distance measured. We will describe the project, the accuracy that can be reached by standard techniques, and discuss a possible improvement to reduce the vertical velocity spread.
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| 19. |
- Pironi, L., et al.
(author)
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Clinical classification of adult patients with chronic intestinal failure due to benign disease: An international multicenter cross-sectional survey
- 2018
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In: Clinical Nutrition. - : Elsevier BV. - 0261-5614. ; 37:2, s. 728-738
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Journal article (peer-reviewed)abstract
- Background & aims: The aim of the study was to evaluate the applicability of the ESPEN 16-category clinical classification of chronic intestinal failure, based on patients' intravenous supplementation (IVS) requirements for energy and fluids, and to evaluate factors associated with those requirements. Methods: ESPEN members were invited to participate through ESPEN Council representatives. Participating centers enrolled adult patients requiring home parenteral nutrition for chronic intestinal failure on March 1st 2015. The following patient data were recorded though a structured database: sex, age, body weight and height, intestinal failure mechanism, underlying disease, IVS volume and energy need. Results: Sixty-five centers from 22 countries enrolled 2919 patients with benign disease. One half of the patients were distributed in 3 categories of the ESPEN clinical classification. 9% of patients required only fluid and electrolyte supplementation. IVS requirement varied considerably according to the pathophysiological mechanism of intestinal failure. Notably, IVS volume requirement represented loss of intestinal function better than IVS energy requirement. A simplified 8 category classification of chronic intestinal failure was devised, based on two types of IVS (either fluid and electrolyte alone or parenteral nutrition admixture containing energy) and four categories of volume. Conclusions: Patients' IVS requirements varied widely, supporting the need for a tool to homogenize patient categorization. This study has devised a novel, simplified eight category IVS classification for chronic intestinal failure that will prove useful in both the clinical and research setting when applied together with the underlying pathophysiological mechanism of the patient's intestinal failure. (C) 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
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| 20. |
- Pironi, L., et al.
(author)
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COVID-19 infection in patients on long-term home parenteral nutrition for chronic intestinal failure
- 2023
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In: Clinical Nutrition Espen. - : Elsevier BV. - 2405-4577. ; 55, s. 212-220
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Journal article (peer-reviewed)abstract
- Background and aims: To investigate the incidence and the severity of COVID-19 infection in patients enrolled in the database for home parenteral nutrition (HPN) for chronic intestinal failure (CIF) of the European Society for Clinical Nutrition and Metabolism (ESPEN). Methods: Period of observation: March 1st, 2020 March 1st, 2021. Inclusion criteria: patients included in the database since 2015 and still receiving HPN on March 1st, 2020 as well as new patients included in the database during the period of observation. Data related to the previous 12 months and recorded on March 1st 2021: 1) occurrence of COVID-19 infection since the beginning of the pandemic (yes, no, unknown); 2) infection severity (asymptomatic; mild, no-hospitalization; moderate, hospitalization no -ICU; severe, hospitalization in ICU); 3) vaccinated against COVID-19 (yes, no, unknown); 4) patient outcome on March 1st 2021: still on HPN, weaned off HPN, deceased, lost to follow up.Results: Sixty-eight centres from 23 countries included 4680 patients. Data on COVID-19 were available for 55.1% of patients. The cumulative incidence of infection was 9.6% in the total group and ranged from 0% to 21.9% in the cohorts of individual countries. Infection severity was reported as: asymptomatic 26.7%, mild 32.0%, moderate 36.0%, severe 5.3%. Vaccination status was unknown in 62.0% of patients, non-vaccinated 25.2%, vaccinated 12.8%. Patient outcome was reported as: still on HPN 78.6%, weaned off HPN 10.6%, deceased 9.7%, lost to follow up 1.1%. A higher incidence of infection (p = 0.04), greater severity of infection (p < 0.001) and a lower vaccination percentage (p = 0.01) were observed in deceased patients. In COVID-19 infected patients, deaths due to infection accounted for 42.8% of total deaths.Conclusions: In patients on HPN for CIF, the incidence of COVID-19 infection differed greatly among countries. Although the majority of cases were reported to be asymptomatic or have mild symptoms only, COVID-19 was reported to be fatal in a significant proportion of infected patients. Lack of vacci-nation was associated with a higher risk of death.(c) 2023 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.
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