Refine
Year of publication
Document Type
- Article (453)
- Preprint (261)
- Contribution to a Periodical (8)
- Conference Proceeding (6)
- Working Paper (6)
- Book (1)
- Report (1)
Has Fulltext
- yes (736)
Is part of the Bibliography
- no (736)
Keywords
- e +-e − Experiments (15)
- BESIII (12)
- Branching fraction (10)
- Particle and Resonance Production (8)
- Charm Physics (6)
- Quarkonium (6)
- Spectroscopy (6)
- Exotics (4)
- Heavy-ion collisions (4)
- Lepton colliders (4)
- portal hypertension (4)
- stochastic differential utility (4)
- COVID-19 (3)
- Charmed mesons (3)
- Diffraction (3)
- Elastic scattering (3)
- Electroweak interaction (3)
- Hadronic decays (3)
- Polarization (3)
- e+-e− Experiments (3)
- Beam Energy Scan (2)
- Biomarkers (2)
- Branching fractions (2)
- Brassica napus (2)
- COVID-19 surveillance (2)
- Cancer (2)
- Charm physics (2)
- Charmonium (2)
- Chiral Magnetic Effect (2)
- Collectivity (2)
- Correlation (2)
- Electroweak Interaction (2)
- Epidemiology (2)
- FBSDE (2)
- Flavour Physics (2)
- Immunology (2)
- Leptonic, semileptonic & radiative decays (2)
- Mechanisms of disease (2)
- Mitochondria (2)
- Non-small cell lung cancer (2)
- Omicron (2)
- Particle decays (2)
- QCD (2)
- RHIC (2)
- Radiative decay (2)
- Radiotherapy (2)
- Rare diseases (2)
- Registries (2)
- SARS-CoV-2 (2)
- SARS-CoV-2 monitoring (2)
- STAR (2)
- Shear viscosity (2)
- Treatment (2)
- asset pricing (2)
- cirrhosis (2)
- consumption-portfolio choice (2)
- incomplete markets (2)
- microdosing (2)
- recursive utility (2)
- 140Ce (1)
- 3years (1)
- ACLF (1)
- ADGRE1 (1)
- AIS (1)
- ALK (1)
- ALK-rearranged NSCLC (1)
- ARDS (1)
- ATM (1)
- Absolute branching fraction (1)
- Acuris (1)
- Acute elbow dislocation (1)
- Advanced biliary tract cancer (1)
- Alpha-synuclein (1)
- Alternative oxidase (1)
- Antibiotic therapy (1)
- Antirheumatic agents (1)
- Araneae (1)
- Artificial Intelligence (1)
- Augenerkrankungen (1)
- Autosomal recessive cutis laxa type 1C (1)
- B-slope (1)
- B.1.1.529 (1)
- BA.4 (1)
- BA.5 (1)
- BESIII detector (1)
- BI1361849 (1)
- BTC (1)
- Bacterial leakage (1)
- Beam energy scan (1)
- Bhabha (1)
- Biodiversity Data (1)
- Biogeography (1)
- Biomedical engineering (1)
- Biomonitoring (1)
- Bipolar disorder (1)
- Born cross section (1)
- Born cross section measurement (1)
- Botanical Collections (1)
- Branching fraction measurement (1)
- CAD/CAM crown (1)
- CAKUT (1)
- CBA (1)
- CEP68 (1)
- COMP (1)
- COVID 19 (1)
- CP violation (1)
- CRVO (1)
- CV9202 (1)
- Cardiac implantable electronic devices (1)
- Cardiac rehabilitation (1)
- Cardiac resynchronization therapy (1)
- Cardiovascular disease risk (1)
- Cardiovascular diseases (1)
- Cement gap (1)
- Charged-particle multiplicity (1)
- Charm quark spatial diffusion coefficient (1)
- Charm vector (1)
- Charmed baryon (1)
- Charmonia (1)
- Charmonium (-like) (1)
- Chest pain unit (1)
- Child (1)
- Chiral magnetic effect (1)
- Circadian (1)
- Cirrhosis (1)
- Classification (1)
- Clinical trial (1)
- Coalescence (1)
- Cognitive impairment (1)
- Cohort studies (1)
- Cold nuclear matter effects (1)
- Colorectal cancer (1)
- Comparative effectiveness research (1)
- Complex II (1)
- Concept paper (1)
- Conometric connection (1)
- Consensus (1)
- Consensus document (1)
- Conservation (1)
- Consumption hump (1)
- Coronary intervention (1)
- Critical care (1)
- Critical point (1)
- Cross section (1)
- D meson (1)
- DME (1)
- DNA-PK (1)
- Dark photon (1)
- Dark sector (1)
- Data Standard (1)
- Data protection (1)
- Data sharing (1)
- Datenschutz (1)
- Dermatomyositis (1)
- Detection workflow (1)
- Deuteron production (1)
- Deutschland (1)
- Di-hadron correlations (1)
- Diagnosis (1)
- Digital (1)
- Digitization (1)
- ECM (1)
- EMR1 (1)
- Ecology (1)
- Ecophysiology (1)
- Ectoparasites (1)
- Education (1)
- Effective form factor (1)
- Einwanderer (1)
- Elastogenesis (1)
- Electromagnetic form factor (1)
- Electromagnetic form factors (1)
- Electromagnetic transitions (1)
- Elliptic flow (1)
- Equity (1)
- Etanercept (1)
- Exercise training (1)
- Experimental nuclear physics (1)
- Experimental particle physics (1)
- Extracellular matrix (1)
- Eye diseases (1)
- EyesiNet (1)
- F4/80 (1)
- FOS: Physical sciences (1)
- Fibulin-4 (1)
- Fibulin-5 (1)
- Flavor changing neutral currents (1)
- Flavor symmetries (1)
- Flow (1)
- Form factors (1)
- Forward physics (1)
- Fracture type (1)
- Fremdbild (1)
- GLM (1)
- Genetics (1)
- Genetics research (1)
- Geschichte 1981-1997 (1)
- Gomphus flavipes (1)
- Groomed jet radius (1)
- HCC (1)
- Hadron-Hadron scattering (experiments) (1)
- Hadronization (1)
- Hand-foot syndrome (1)
- Hantavirus (1)
- Health information (1)
- Health-seeking behaviour (1)
- Heart failure (1)
- Heavy Ion Experiments (1)
- Heavy Quark Production (1)
- Heavy ion collisions (1)
- Heavy-Ion Collision (1)
- Heavy-flavor decay electron (1)
- Heavy-ion (1)
- Helicity amplitude analysis (1)
- Helpline (1)
- Herbaria (1)
- Hif1α (1)
- High Energy Physics - Experiment (hep-ex) (1)
- Higher moments (1)
- Hyperons (1)
- Hypertension (1)
- Hypofractionated radiotherapy (1)
- ICU (1)
- IHMCIF (1)
- IL-6 (1)
- ILUVIEN (1)
- IR (1)
- ISS (1)
- Immunogenetics (1)
- Immunomonitoring (1)
- Implantable cardioverter-defibrillator (1)
- Inclusive branching fraction (1)
- Inflammation (1)
- Initial state radiation (1)
- Integrative Modeling (1)
- Interference fragmentation function (1)
- Invisible decays (1)
- J/ψ suppression (1)
- Jet substructure (1)
- K0S (1)
- K3EDTA plasma sampling (1)
- K48-linked (1)
- K63-linked (1)
- Konzeptpapier (1)
- Landscape ecology (1)
- Landschaftsökologie (1)
- Latent transforming growth factor β-binding protein 4 (1)
- Lehre (1)
- Libellen (1)
- Lifestyle (1)
- Lipidomics (1)
- Liver diseases (1)
- Ltbp-4 (1)
- Ltbp-4L (1)
- Ltbp-4S (1)
- L´evy framework (1)
- MACS (1)
- MCP-1 (1)
- MMPs (1)
- MRSA (1)
- MYCN amplification (1)
- Marginal integrity (1)
- Metabolomics (1)
- Microgap (1)
- Mitochondrial disease (1)
- Models & methods for nuclear reactions (1)
- Molecular diagnostic testing (1)
- Molecular medicine (1)
- Multiple parton interactions (1)
- Multivariate analysis (1)
- Myotis myotis (1)
- NAFLD (1)
- NET (1)
- NMDA IgA/IgM antibodies (1)
- NMDA antibody (1)
- NMR spectroscopy (1)
- NSCLC (1)
- NSTEMI (1)
- Net-charge correlations (1)
- Net-charge fluctuations (1)
- Netzhaut (1)
- Neutrinos (1)
- Neutron physics (1)
- Nonflow (1)
- Nuclear reactions (1)
- Nutzen (1)
- Oncogenes (1)
- Open Access (1)
- Ophiogomphus cecilia (1)
- Orphan disease (1)
- Osteoporosis (1)
- Outcome (1)
- Oxidative phosphorylation (1)
- PBSC (1)
- PDB-Dev (1)
- PDBx/mmCIF (1)
- PDE‐5‐inhibitor (1)
- PDGFRβ (1)
- PI3K (1)
- PRRT (1)
- PTEN (1)
- Pacemaker (1)
- Parkinson disease (1)
- Parkinson’s disease (1)
- Particle and resonance production (1)
- Particle phenomena (1)
- Patient safety (1)
- Periodontal disease (1)
- Periodontal therapy (1)
- Pest-crop interactions (1)
- Phalangeal fractures (1)
- Physical activity (1)
- Plasminogen (1)
- Platelets (1)
- Pneumonia (1)
- Portal veins (1)
- Poverty (1)
- Pre-analytics (1)
- Preclinical research (1)
- Predictive markers (1)
- Prevention (1)
- Prognosis (1)
- Prognostic models (1)
- Prostaglandin (1)
- Proton (1)
- Proton-proton collisions (1)
- Proton–proton collisions (1)
- Psychiatric disorders (1)
- Psychiatry (1)
- Puumala virus (1)
- Quantum chromodynamics (1)
- RAS pathway (1)
- RNA (1)
- RNA-binding proteins (1)
- Radiative capture (1)
- Rapps (1)
- Rare decays (1)
- Real world (1)
- Register (1)
- Remission (1)
- Research Infrastructure (1)
- Resonance reactions (1)
- Respiratory chain (1)
- Retina (1)
- Retro-IDEAL (1)
- Rh(II) catalysis (1)
- Rheumatoid arthritis (1)
- Rodent-associated infections (1)
- Roosting place (1)
- SARS CoV 2 (1)
- SD-OCT (1)
- SLC20A1 (1)
- SPSS (1)
- STED superresolution (1)
- Sampling protocol (1)
- Schulbuch (1)
- Schädling (1)
- Seasonal variation (1)
- Seltene Erkrankungen (1)
- Semantics (1)
- Semi-leptonic decays (1)
- Single-molecule biophysics (1)
- Social determinants (1)
- SoftDrop (1)
- Solar insolation (1)
- Sorafenib (1)
- Spatial scales (1)
- Spatio-temporal patterns (1)
- Spin alignment (1)
- Spine care (1)
- Spinturnix myoti (1)
- Splitting function (1)
- Standardization (1)
- Staphylococcus aureus (1)
- Stentoplasty (1)
- Steroid (1)
- Student (1)
- Suicide (1)
- Sunlight (1)
- Super-resolution microscopy (1)
- Surgical oncology (1)
- TACE (1)
- TGR(mREN2)27 (1)
- TP53 mutation status (1)
- Taxonomy (1)
- Techniques Electromagnetic calorimeters (1)
- Telemedicine (1)
- Thermal model (1)
- Thoracic trauma (1)
- Threshold effect (1)
- Thrombosis (1)
- Thromboxane (1)
- Transversity (1)
- UWB diagnostics (1)
- VEGF (1)
- VEGFR-2 (1)
- VEGFR-3 (1)
- Variant of concern (1)
- Veins (1)
- Vertebral augmentation (1)
- Vertebral body stenting (1)
- Vertebral fracture (1)
- Vitreous samples (1)
- Wastewater-based epidemiology (WBE) (1)
- Western diet (1)
- Worldwide Protein Data Bank (1)
- X-ray crystallography (1)
- Y states (1)
- accessory proteins (1)
- acute decompensation (1)
- acute myeloid leukemia (1)
- acute-on-chronic liver failure (1)
- adaptive cardiac remodelling (1)
- adverse events (1)
- alternative oxidase (1)
- anaesthesia in orthopaedics (1)
- anaesthetics (1)
- autoantibodies (1)
- azaindole (1)
- backward stochastic differential equation (1)
- bioactivity testing (1)
- bladder exstrophy-epispadias complex (1)
- bleomycin (1)
- bundle (1)
- c-kit (1)
- capture (1)
- cardiac ischaemia‐reperfusion (1)
- cartilage (1)
- cell stress (1)
- cell-free protein synthesis (1)
- center-of-mass energy (1)
- centrosome (1)
- centrosome linker (1)
- cerium (1)
- certainty equivalents (1)
- charmonium-like states (1)
- cloacal malformation (1)
- complications (1)
- computed tomography (1)
- consumption hump (1)
- convergence (1)
- cross-section (1)
- cytarabine dose (1)
- decays (1)
- diabetic macular edema (1)
- diazo compounds (1)
- dimuon (1)
- dynamic programming (1)
- e+e − annihilation (1)
- e+e⁻ − Experiments (1)
- e+e− Experiments (1)
- easyPACId (1)
- ectosomes (1)
- education (1)
- elderly (1)
- electron transport chain (1)
- electron-positron collision (1)
- epigeic spiders (1)
- epigäische Spinnen (1)
- erectile dysfunction (1)
- exosomes (1)
- extracellular vesicles (1)
- fibrogenesis (1)
- fixed point approach (1)
- fluocinolone acetonide (1)
- fluorescent dye (1)
- functional genetics (1)
- generalist predators (1)
- generalistische Prädatoren (1)
- geriatric medicine (1)
- global change (1)
- guidelines (1)
- habit formation (1)
- habitat destruction (1)
- hadron spectroscopy (1)
- hadronic events (1)
- health information exchange (1)
- heavy-ion collisions (1)
- helicity amplitude analysis (1)
- hematotoxicity (1)
- hepatic encephalopathy (1)
- hepatic stellate cells (1)
- hepatocellular cancer (1)
- high-risk neuroblastoma (1)
- immunity (1)
- impatience (1)
- in vitro models (1)
- inclusive J/ψ decays (1)
- inflammation (1)
- intrinsically disordered region (1)
- jumps (1)
- kidney formation (1)
- land use (1)
- leisure (1)
- life-cycle utility maximization (1)
- liver (1)
- liver fibrosis (1)
- mRNA active cancer immunotherapy (1)
- macrophage (1)
- metallo β lactamases (1)
- microparticles (1)
- microvesicles (1)
- microwave ablation (1)
- microwave breast imaging (1)
- minimal information requirements (1)
- mouse (1)
- mouse model (1)
- multiresistant bacteria (1)
- n_TOF (1)
- natural products (1)
- nematophin (1)
- neuroendocrine tumor (1)
- neutralizing antibodies (1)
- neutron (1)
- nonstructural proteins (1)
- non‐selective beta‐blocker (1)
- normalization (1)
- nucleosynthesis (1)
- number of J/ψ events (1)
- optimal investment (1)
- osteoarthritis (1)
- oval split ring resonator (1)
- p+p collisions (1)
- p53 pathway (1)
- patient study (1)
- peptide receptor radionuclide therapy (1)
- peripheral blood stem cell collection (1)
- polyubiquitin (1)
- portosystemic shunt (1)
- prevention (1)
- primary biliary cholangitis (1)
- proteobacteria (1)
- qualitative research (1)
- quality control (1)
- rare diseases (1)
- reactive oxygen species (1)
- renin-angiotensin system (1)
- reproducibility (1)
- resectability (1)
- rigor (1)
- rootletin (1)
- s-process (1)
- second line therapy (1)
- sequential ALK-inhibitor therapy (1)
- simplified production (1)
- sorafenib (1)
- sphingolipid sphingosine-1-phosphate (1)
- sphingolipids (1)
- sphingosine-1-phosphate receptor 5 (1)
- spike protein (1)
- spontaneous portosystemic shunt (1)
- standardization (1)
- steatosis (1)
- stochastic volatility (1)
- structural proteins (1)
- surgery (1)
- systemic sclerosis (1)
- tetraquark (1)
- theranostics (1)
- thiol inhibitors (1)
- thrombospondins (1)
- treatment (1)
- treatment response (1)
- trigger efficiency (1)
- ubiquitin-conjugating enzymes (1)
- urinary tract development (1)
- ursodeoxycholic acid (1)
- variant of concern (1)
- variants of concern (1)
- wage hump (1)
- wastewater-based epidemiology (WBE) (1)
- welfare loss (1)
- wwPDB (1)
- zebrafish development (1)
- Λ+c baryon (1)
- Σ hyperon (1)
- Υ suppression (1)
- ψ(3686) (1)
- fibrogenesis (1)
Institute
- Physik (465)
- Frankfurt Institute for Advanced Studies (FIAS) (106)
- Medizin (92)
- Geowissenschaften (23)
- Präsidium (8)
- Biochemie und Chemie (7)
- Biochemie, Chemie und Pharmazie (7)
- Biowissenschaften (7)
- Wirtschaftswissenschaften (7)
- Center for Financial Studies (CFS) (6)
Background: Although being considered as a rarely observed HIV-1 protease mutation in clinical isolates, the L76V-prevalence increased 1998-2008 in some European countries most likely due to the approval of Lopinavir, Amprenavir and Darunavir which can select L76V. Beside an enhancement of resistance, L76V is also discussed to confer hypersusceptibility to the drugs Atazanavir and Saquinavir which might enable new treatment strategies by trying to take advantage of particular mutations. Results: Based on a cohort of 47 L76V-positive patients, we examined if there might exist a clinical advantage for L76V-positive patients concerning long-term success of PI-containing regimens in patients with limited therapy options. Genotypic- and phenotypic HIV-resistance tests from 47 mostly multi-resistant, L76V-positive patients throughout Germany were accomplished retrospectively 1999-2009. Five genotype-based drug-susceptibility predictions received from online interpretation-tools for Atazanavir, Saquinavir, Amprenavir and Lopinavir, were compared to phenotype-based predictions that were determined by using a recombinant virus assay along with a Virtual Phenotype™(Virco). The clinical outcome of the L76V-adapted follow-up therapy was determined by monitoring viral load for 96 weeks. Conclusions: In this analysis, the mostly used interpretation systems overestimated the L76V-mutation concerning Atazanavir- and SQV resistance. In fact, a clear benefit in drug susceptibility for these drugs was observed in phenotype analysis after establishment of L76V. More importantly, long-term therapy success was significantly higher in patients receiving Atazanavir and/or Saquinavir plus one L76V-selecting drug compared to patients without L76V-selecting agents (p = 0.002). In case of L76V-occurrence ATV and/or SQV may represent encouraging options for patients in deep salvage situations.
Matrix metalloproteinases (MMPs) play crucial roles in tissue homeostasis and pathologies by remodeling the extracellular matrix. Previous studies have demonstrated the biological activities of MMP-derived cleavage products. Furthermore, specific fragments can serve as biomarkers. Therefore, an in vitro cleavage assay to identify substrates and characterize cleavage patterns could provide important insight in disease-relevant mechanisms and the identification of novel biomarkers. In the pathogenesis of osteoarthritis (OA), MMP-2, -8, -9 and -13 are of vital importance. However, it is unclear which protease can cleave which matrix component. To address this question, we established an in vitro cleavage assay using recombinantly expressed MMPs and the two cartilage matrix components, COMP and thrombospondin-4. We found a time- and concentration-dependent degradation and an MMP-specific cleavage pattern for both proteins. Cleavage products can now be enriched and purified to investigate their biological activity. To verify the in vivo relevance, we compared the in vitro cleavage patterns with serum and synovial fluid from OA patients and could indeed detect fragments of similar size in the human samples. The cleavage assay can be adapted to other MMPs and substrates, making it a valuable tool for many research fields.
The idea of slow-neutron capture nucleosynthesis formulated in 1957 triggered a tremendous experimental effort in different laboratories worldwide to measure the relevant nuclear physics input quantities, namely (n,γ) cross sections over the stellar temperature range (from few eV up to several hundred keV) for most of the isotopes involved from Fe up to Bi. A brief historical review focused on total energy detectors will be presented to illustrate how, advances in instrumentation have led, over the years, to the assessment and discovery of many new aspects of s-process nucleosynthesis and to the progressive refinement of theoretical models of stellar evolution. A summary will be presented on current efforts to develop new detection concepts, such as the Total-Energy Detector with γ-ray imaging capability (i-TED). The latter is based on the simultaneous combination of Compton imaging with neutron time-of-flight (TOF) techniques, in order to achieve a superior level of sensitivity and selectivity in the measurement of stellar neutron capture rates.
An important experimental program on Nuclear Astrophysics is being carried out at the n_TOF since several years, in order to address the still open issues in stellar and primordial nucleosynthesis. Several neutron capture reactions relevant to s-process nucleosynthesis have been measured so far, some of which on important branching point radioisotopes. Furthermore, the construction of a second experimental area has recently opened the way to challenging measurements of (n, charged particle) reactions on isotopes of short half-life. The Nuclear Astrophysics program of the n_TOF Collaboration is here described, with emphasis on recent results relevant for stellar nucleosynthesis, stellar neutron sources and primordial nucleosynthesis.
he study of the resonant structures in neutron-nucleus cross-sections, and therefore of the compound-nucleus reaction mechanism, requires spectroscopic measurements to determine with high accuracy the energy of the neutron interacting with the material under study.
To this purpose, the neutron time-of-flight facility n_TOF has been operating since 2001 at CERN. Its characteristics, such as the high intensity instantaneous neutron flux, the wide energy range from thermal to few GeV, and the very good energy resolution, are perfectly suited to perform high-quality measurements of neutron-induced reaction cross sections. The precise and accurate knowledge of these cross sections plays a fundamental role in nuclear technologies, nuclear astrophysics and nuclear physics.
Two different measuring stations are available at the n_TOF facility, called EAR1 and EAR2, with different characteristics of intensity of the neutron flux and energy resolution. These experimental areas, combined with advanced detection systems lead to a great flexibility in performing challenging measurement of high precision and accuracy, and allow the investigation isotopes with very low cross sections, or available only in small quantities, or with very high specific activity.
The characteristics and performances of the two experimental areas of the n_TOF facility will be presented, together with the most important measurements performed to date and their physics case. In addition, the significant upcoming measurements will be introduced.
The aim of this work is to provide a precise and accurate measurement of the 238U(n,γ) reaction cross section in the energy region from 1 eV to 700 keV. This reaction is of fundamental importance for the design calculations of nuclear reactors, governing the behavior of the reactor core. In particular, fast reactors, which are experiencing a growing interest for their ability to burn radioactive waste, operate in the high energy region of the neutron spectrum. In this energy region most recent evaluations disagree due to inconsistencies in the existing measurements of up to 15%. In addition, the assessment of nuclear data uncertainty performed for innovative reactor systems shows that the uncertainty in the radiative capture cross section of 238U should be further reduced to 1–3% in the energy region from 20 eV to 25 keV. To this purpose, addressed by the Nuclear Energy Agency as a priority nuclear data need, complementary experiments, one at the GELINA and two at the n_TOF facility, were proposed and carried out within the 7th Framework Project ANDES of the European Commission. The results of one of these 238U(n,γ) measurements performed at the n_TOF CERN facility are presented in this work. The γ-ray cascade following the radiative neutron capture has been detected exploiting a setup of two C6D6 liquid scintillators. Resonance parameters obtained from this work are on average in excellent agreement with the ones reported in evaluated libraries. In the unresolved resonance region, this work yields a cross section in agreement with evaluated libraries up to 80 keV, while for higher energies our results are significantly higher.
Fission program at n_TOF
(2019)
Since its start in 2001 the n_TOF collaboration developed a measurement program on fission, in view of advanced fuels in new generation reactors. A special effort was made on measurement of cross sections of actinides, exploiting the peculiarity of the n_TOF neutron beam which spans a huge energy domain, from the thermal region up to GeV. Moreover fission fragment angular distributions have also been measured. An overview of the cross section results achieved with different detectors is presented, including a discussion of the 237Np case where discrepancies showed up between different detector systems. The results on the anisotropy of the fission fragments and its implication on the mechanism of neutron absorption, and in applications, are also shown.
The study of neutron-induced reactions is of high relevance in a wide variety of fields, ranging from stellar nucleosynthesis and fundamental nuclear physics to applications of nuclear technology. In nuclear energy, high accuracy neutron data are needed for the development of Generation IV fast reactors and accelerator driven systems, these last aimed specifically at nuclear waste incineration, as well as for research on innovative fuel cycles. In this context, a high luminosity Neutron Time Of Flight facility, n_TOF, is operating at CERN since more than a decade, with the aim of providing new, high accuracy and high resolution neutron cross-sections. Thanks to the features of the neutron beam, a rich experimental program relevant to nuclear technology has been carried out so far. The program will be further expanded in the near future, thanks in particular to a new high-flux experimental area, now under construction.
The accurate knowledge of the neutron-induced fission cross-sections of actinides and other isotopes involved in the nuclear fuel cycle is essential for the design of advanced nuclear systems, such as Generation-IV nuclear reactors. Such experimental data can also provide the necessary feedback for the adjustment of nuclear model parameters used in the evaluation process, resulting in the further development of nuclear fission models. In the present work, the 240Pu(n,f) cross-section was measured at CERN's n_TOF facility relative to the well-known 235U(n,f) cross section, over a wide range of neutron energies, from meV to almost MeV, using the time-of-flight technique and a set-up based on Micromegas detectors. This measurement was the first experiment to be performed at n_TOF's new experimental area (EAR-2), which offers a significantly higher neutron flux compared to the already existing experimental area (EAR-1). Preliminary results as well as the experimental procedure, including a description of the facility and the data handling and analysis, are presented.
The slow neutron capture process (s-process) is responsible for producing about half of the elemental abundances heavier than iron in the universe. Neutron capture cross sections on stable isotopes are a key nuclear physics input for s-process studies. The 72Ge(n, γ) cross section has an important influence on production of isotopes between Ge and Zr during s-process in massive stars and therefore experimental data are urgently required. 72Ge(n, γ) was measured at the neutron time-of-flight facility n_TOF (CERN) for the first time at stellar energies. The measurement was performed using an enriched 72GeO2 sample at a flight path of 185m with a set of liquid scintillation detectors (C6D6). The motivation, experiment and current status of the data analysis are reported.
The spent fuel of current nuclear reactors contains fissile plutonium isotopes that can be combined with 238U to make mixed oxide (MOX) fuel. In this way the Pu from spent fuel is used in a new reactor cycle, contributing to the long-term sustainability of nuclear energy. The use of MOX fuels in thermal and fast reactors requires accurate capture and fission cross sections. For the particular case of 242Pu, the previous neutron capture cross section measurements were made in the 70's, providing an uncertainty of about 35% in the keV region. In this context, the Nuclear Energy Agency recommends in its “High Priority Request List” and its report WPEC-26 that the capture cross section of 242Pu should be measured with an accuracy of at least 7–12% in the neutron energy range between 500 eV and 500 keV. This work presents a brief description of the measurement performed at n_TOF-EAR1, the data reduction process and the first ToF capture measurement on this isotope in the last 40 years, providing preliminary individual resonance parameters beyond the current energy limits in the evaluations, as well as a preliminary set of average resonance parameters.
The Cosmological Lithium Problem refers to the large discrepancy between the abundance of primordial 7Li predicted by the standard theory of Big Bang Nucleosynthesis and the value inferred from the so-called “Spite plateau” in halo stars. A possible explanation for this longstanding puzzle in Nuclear Astrophysics is related to the incorrect estimation of the destruction rate of 7Be, which is responsible for the production of 95% of primordial Lithium. While charged-particle induced reactions have mostly been ruled out, data on the 7Be(n,α) and 7Be(n,p) reactions are scarce or completely missing, so that a large uncertainty still affects the abundance of 7Li predicted by the standard theory of Big Bang Nucleosynthesis. Both reactions have been measured at the n_TOF facility at CERN, providing for the first time data in a wide neutron energy range.
The neutron capture cross section of 58Ni was measured at the neutron time of flight facility n_TOF at CERN, from 27 meV to 400 keV neutron energy. Special care has been taken to identify all the possible sources of background, with the so-called neutron background obtained for the first time using high-precision GEANT4 simulations. The energy range up to 122 keV was treated as the resolved resonance region, where 51 resonances were identified and analyzed by a multilevel R-matrix code SAMMY. Above 122 keV the code SESH was used in analyzing the unresolved resonance region of the capture yield. Maxwellian averaged cross sections were calculated in the temperature range of kT = 5 – 100 keV, and their astrophysical implications were investigated.
The 14N(n,p)14C reaction is of interest in neutron capture therapy, where nitrogen-related dose is the main component due to low-energy neutrons, and in astrophysics, where 14N acts as a neutron poison in the s-process. Several discrepancies remain between the existing data obtained in partial energy ranges: thermal energy, keV region and resonance region. Purpose: Measuring the 14N(n,p)14C cross section from thermal to the resonance region in a single measurement for the first time, including characterization of the first resonances, and providing calculations of Maxwellian averaged cross sections (MACS). Method: Time-of-flight technique. Experimental Area 2 (EAR-2) of the neutron time-of-flight (n_TOF) facility at CERN. 10B(n,α)7Li and 235U(n,f) reactions as references. Two detection systems running simultaneously, one on-beam and another off-beam. Description of the resonances with the R-matrix code sammy. Results: The cross section has been measured from sub-thermal energy to 800 keV resolving the two first resonances (at 492.7 and 644 keV). A thermal cross-section (1.809±0.045 b) lower than the two most recent measurements by slightly more than one standard deviation, but in line with the ENDF/B-VIII.0 and JEFF-3.3 evaluations has been obtained. A 1/v energy dependence of the cross section has been confirmed up to tens of keV neutron energy. The low energy tail of the first resonance at 492.7 keV is lower than suggested by evaluated values, while the overall resonance strength agrees with evaluations. Conclusions: Our measurement has allowed to determine the 14N(n,p) cross-section over a wide energy range for the first time. We have obtained cross-sections with high accuracy (2.5 %) from sub-thermal energy to 800 keV and used these data to calculate the MACS for kT = 5 to kT = 100 keV.
Although the 12C(n,p)12B and 12C(n,d)11B reactions are of interest in several fields of basic and applied Nuclear Physics the present knowledge of these two cross-sections is far from being accurate and reliable, with both evaluations and data showing sizable discrepancies. As part of the challenging n_TOF program on (n,cp) nuclear reactions study, the energy differential cross-sections of the 12C(n,p)12B and 12C(n,d)11 B reactions have been measured at CERN from the reaction thresholds up to 30 MeV neutron energy. Both measurements have been recently performed at the long flight-path (185 m) experimental area of the n_TOF facility at CERN using a pure (99.95%) rigid graphite target and two silicon telescopes. In this paper an overview of the experiment is presented together with a few preliminary results.
The 236U isotope plays an important role in nuclear systems, both for future and currently operating ones. The actual knowledge of the capture reaction of this isotope is satisfactory in the thermal region, but it is considered insufficient for Fast Reactor and ADS applications. For this reason the 236U(n, γ) reaction cross-section has been measured for the first time in the whole energy region from thermal energy up to 1 MeV at the n_TOF facility with two different detection systems: an array of C6D6 detectors, employing the total energy deposited method, and a FX1 total absorption calorimeter (TAC), made of 40 BaF2 crystals. The two n_TOF data sets agree with each other within the statistical uncertainty in the Resolved Resonance Region up to 800 eV, while sizable differences (up to ≃ 20%) are found relative to the current evaluated data libraries. Moreover two new resonances have been found in the n_TOF data. In the Unresolved Resonance Region up to 200 keV, the n_TOF results show a reasonable agreement with previous measurements and evaluated data.
Wastewater-based SARS-CoV-2 epidemiology (WBE) has been established as an important tool to support individual testing strategies. Omicron sub-variants BA.4/5 have spread globally displacing the predeceasing variants. Due to the severe transmissibility and immune escape potential of BA.4/5, early monitoring was required to asses and implement countermeasures in time.
In this study, we monitored the prevalence of SARS-CoV-2 BA.4/5 at six municipal wastewater treatment plants (WWTPs) in the Federal State of North-Rhine-Westphalia (NRW, Germany) in May and June 2022. Initially, L452R-specific primers/probes originally designed for SARS-CoV-2 Delta detection were validated using inactivated authentic viruses and evaluated for their suitability to detect BA.4/5. Subsequently, the assay was used for RT-qPCR analysis of RNA purified from wastewater obtained twice a week at six WWTPs. The occurrence of L452R carrying RNA was detected in early May 2022 and the presence of BA.4/5 was confirmed by variant-specific single nucleotide polymorphism PCR (SNP-PCR) targeting E484A/F486V. Finally, the mutant fractions were quantitatively monitored by digital PCR confirming BA.4/5 as the majority variant by 5th June 2022.
In conclusions, the successive workflow using RT-qPCR, variant-specific SNP-PCR, and RT-dPCR demonstrates the strength of WBE as a versatile tool to rapidly monitor variant spreading independent of individual test capacities.
The neutron sensitivity of the C6D6 detector setup used at n_TOF facility for capture measurements has been studied by means of detailed GEANT4 simulations. A realistic software replica of the entire n_TOF experimental hall, including the neutron beam line, sample, detector supports and the walls of the experimental area has been implemented in the simulations. The simulations have been analyzed in the same manner as experimental data, in particular by applying the Pulse Height Weighting Technique. The simulations have been validated against a measurement of the neutron background performed with a natC sample, showing an excellent agreement above 1 keV. At lower energies, an additional component in the measured natC yield has been discovered, which prevents the use of natC data for neutron background estimates at neutron energies below a few hundred eV. The origin and time structure of the neutron background have been derived from the simulations. Examples of the neutron background for two different samples are demonstrating the important role of accurate simulations of the neutron background in capture cross-section measurements.
Understanding the nano-architecture of protein machines in diverse sub-cellular compartments remains a challenge despite rapid progress in super-resolution microscopy. While singlemolecule localization microscopy techniques allow the visualization and identification of cellular structures with near-molecular resolution, multiplex-labeling of tens of target proteins within the same sample has not yet been achieved routinely. However, single sample multiplexing is essential to detect patterns that threaten to get lost in multi-sample averaging. Here, we report maS3TORM (multiplexed automated serial staining stochastic optical reconstruction microscopy), a microscopy approach capable of fully automated 3D dSTORM imaging and solution exchange employing a re-staining protocol to achieve highly multiplexed protein localization within individual biological samples. We demonstrate 3D super-resolution images of 15 target proteins in single cultured cells and 16 targets in individual neuronal tissue samples with <10 nm localization precision. This allowed us to define novel nano-architectural features of protein distribution within the presynaptic nerve terminal.
The 33S(n,α)30Si cross section measurement, using 10B(n,α) as reference, at the n_TOF Experimental Area 2 (EAR2) facility at CERN is presented. Data from 0.01 eV to 100 keV are provided and, for the first time, the cross section is measured in the range from 0.01 eV to 10 keV. These data may be used for a future evaluation of the cross section because present evaluations exhibit large discrepancies. The 33S(n,α)30Si reaction is of interest in medical physics because of its possible use as a cooperative target to boron in Neutron Capture Therapy (NCT).
The neutron capture cross section of some unstable nuclei is especially relevant for s-process nucleosynthesis studies. This magnitude is crucial to determine the local abundance pattern, which can yield valuable information of the s-process stellar environment. In this work we describe the neutron capture (n,γ) measurement on two of these nuclei of interest, 204Tl and 171Tm, from target production to the final measurement, performed successfully at the n_TOF facility at CERN in 2014 and 2015. Preliminary results on the ongoing experimental data analysis will also be shown. These results include the first ever experimental observation of capture resonances for these two nuclei.
The CERN n_TOF neutron beam facility is characterized by a very high instantaneous neutron flux, excellent TOF resolution at the 185 m long flight path (EAR-1), low intrinsic background and coverage of a wide range of neutron energies, from thermal to a few GeV. These characteristics provide a unique possibility to perform high-accuracy measurements of neutron-induced reaction cross-sections and angular distributions of interest for fundamental and applied Nuclear Physics. Since 2001, the n_TOF Collaboration has collected a wealth of high quality nuclear data relevant for nuclear astrophysics, nuclear reactor technology, nuclear medicine, etc. The overall efficiency of the experimental program and the range of possible measurements has been expanded with the construction of a second experimental area (EAR-2), located 20 m on the vertical of the n_TOF spallation target. This upgrade, which benefits from a neutron flux 30 times higher than in EAR-1, provides a substantial extension in measurement capabilities, opening the possibility to collect data on neutron cross-section of isotopes with short half-lives or available in very small amounts. This contribution will outline the main characteristics of the n_TOF facility, with special emphasis on the new experimental area. In particular, we will discuss the innovative features of the EAR-2 neutron beam that make possible to perform very challenging measurements on short-lived radioisotopes or sub-mg samples, out of reach up to now at other neutron facilities around the world. Finally, the future perspectives of the facility will be presented.
The neutron capture cross section of several key unstable isotopes acting as branching points in the s-process are crucial for stellar nucleosynthesis studies, but they are very challenging to measure due to the difficult production of sufficient sample material, the high activity of the resulting samples, and the actual (n,γ) measurement, for which high neutron fluxes and effective background rejection capabilities are required. As part of a new program to measure some of these important branching points, radioactive targets of 147Pm and 171Tm have been produced by irradiation of stable isotopes at the ILL high flux reactor. Neutron capture on 146Nd and 170Er at the reactor was followed by beta decay and the resulting matrix was purified via radiochemical separation at PSI. The radioactive targets have been used for time-of-flight measurements at the CERN n_TOF facility using the 19 and 185 m beam lines during 2014 and 2015. The capture cascades were detected using a set of four C6D6 scintillators, allowing to observe the associated neutron capture resonances. The results presented in this work are the first ever determination of the resonance capture cross section of 147Pm and 171Tm. Activation experiments on the same 147Pm and 171Tm targets with a high-intensity 30 keV quasi-Maxwellian flux of neutrons will be performed using the SARAF accelerator and the Liquid-Lithium Target (LiLiT) in order to extract the corresponding Maxwellian Average Cross Section (MACS). The status of these experiments and preliminary results will be presented and discussed as well.
Neutron-induced reaction cross sections are important for a wide variety of research fields ranging from the study of nuclear level densities, nucleosynthesis to applications of nuclear technology like design, and criticality and safety assessment of existing and future nuclear reactors, radiation dosimetry, medical applications, nuclear waste transmutation, accelerator-driven systems and fuel cycle investigations. Simulations and calculations of nuclear technology applications largely rely on evaluated nuclear data libraries. The evaluations in these libraries are based both on experimental data and theoretical models. CERN’s neutron time-of-flight facility n_TOF has produced a considerable amount of experimental data since it has become fully operational with the start of its scientific measurement programme in 2001. While for a long period a single measurement station (EAR1) located at 185 m from the neutron production target was available, the construction of a second beam line at 20 m (EAR2) in 2014 has substantially increased the measurement capabilities of the facility. An outline of the experimental nuclear data activities at n_TOF will be presented.
New results are presented of the 234U neutron-induced fission cross section, obtained with high accuracy in the resonance region by means of two methods using the 235U(n,f) as reference. The recent evaluation of the 235U(n,f) obtained with SAMMY by L. C. Leal et al. (these Proceedings), based on previous n_TOF data [1], has been used to calculate the 234U(n,f) cross section through the 234U/235U ratio, being here compared with the results obtained by using the n_TOF neutron flux.
The n_TOF facility operates at CERN with the aim of addressing the request of high accuracy nuclear data for advanced nuclear energy systems as well as for nuclear astrophysics. Thanks to the features of the neutron beam, important results have been obtained on neutron induced fission and capture cross sections of U, Pu and minor actinides. Recently the construction of another beam line has started; the new line will be complementary to the first one, allowing to further extend the experimental program foreseen for next measurement campaigns.
Wastewater-based SARS-CoV-2 epidemiology (WBE) has been established as an important tool to support individual testing strategies. The Omicron sub-variants BA.4/BA.5 have spread globally, displacing the preceding variants. Due to the severe transmissibility and immune escape potential of BA.4/BA.5, early monitoring was required to assess and implement countermeasures in time. In this study, we monitored the prevalence of SARS-CoV-2 BA.4/BA.5 at six municipal wastewater treatment plants (WWTPs) in the Federal State of North Rhine-Westphalia (NRW, Germany) in May and June 2022. Initially, L452R-specific primers/probes originally designed for SARS-CoV-2 Delta detection were validated using inactivated authentic viruses and evaluated for their suitability for detecting BA.4/BA.5. Subsequently, the assay was used for RT-qPCR analysis of RNA purified from wastewater obtained twice a week at six WWTPs. The occurrence of L452R carrying RNA was detected in early May 2022, and the presence of BA.4/BA.5 was confirmed by variant-specific single nucleotide polymorphism PCR (SNP-PCR) targeting E484A/F486V and NGS sequencing. Finally, the mutant fractions were quantitatively monitored by digital PCR, confirming BA.4/BA.5 as the majority variant by 5 June 2022. In conclusion, the successive workflow using RT-qPCR, variant-specific SNP-PCR, and RT-dPCR demonstrates the strength of WBE as a versatile tool to rapidly monitor variants spreading independently of individual test capacities.
Hintergrund: Die Ophthalmoskopie ist Bestandteil des medizinischen Curriculums, jedoch das Vermitteln der Inhalte oft unbefriedigend, da ein systematisches Lernen von Pathologien und deren Behandlungen dadurch erschwert ist, dass oftmals das passende Patientengut nicht zur Verfügung steht und dadurch gesunde Studenten einander untersuchen müssen. Aus diesem Grund haben wir eine Online-Plattform entwickelt, die in Kombination mit simulationsgestütztem Training sowohl das eigenständige als auch das angeleitete Lernen von Untersuchungsmethoden und Pathologien ermöglicht.
Ziel der Arbeit: Ziel der vorliegenden Arbeit war, ein Format für die Verbesserung der Lehre der direkten und indirekten Ophthalmoskopie im Studierendenunterricht zu evaluieren. Dabei wurden praktische Übungen an Virtual-Reality-basierten Simulatoren mit neu entwickelten und an den Lehrkatalog angepassten theoretischen Inhalten in der Online-Plattform EyesiNet verschränkt.
Material und Methoden: Die Studierenden bearbeiteten am ersten sowie am letzten Praktikumstag zufällig ausgewählte Fälle, die ihnen von den Eyesi Direct- und Eyesi Indirect-Simulatoren präsentiert wurden. Zwischen diesen beiden Einheiten konnten sie sich auf freiwilliger Basis mit den theoretischen Grundlagen typischer ophthalmologischer Krankheitsbilder im EyesiNet beschäftigen.
Ergebnisse: Eyesi Direct: Die Bewertung des Simulators ergab am ersten Praktikumstag für beide Gruppen keinen signifikant unterschiedlichen Wissensstand (p = 0,29). In der Gruppe OHNE Training (n = 54) ergab sich am letzten Praktikumstag mit p = 0,02 eine signifikante Verbesserung dieser Bewertung, jedoch mit einer geringen Effektgröße von 0,1. In der Gruppe MIT Training (n = 32) konnte mit p = 0,0004 eine hoch signifikante Verbesserung mit einer Effektgröße von 0,3 nach Rosenthal festgestellt werden. Eyesi Indirect: Die simulatorgestützte Bewertung ergab am ersten Praktikumstag keinen signifikanten Unterschied im Wissensstand der beiden Gruppen (p = 0,1). Nach dem Training schnitten zwar beide Gruppen etwas besser ab, jedoch ohne signifikanten Unterschied (OHNE Training p = 0,41/MIT Training p = 0,17).
Diskussion: Die Online-Plattform EyesiNet unterstützt beim Erlernen der wichtigsten Erkrankungsbilder. Lerninhalte werden reproduzierbar und auf für alle Lernenden standardisierte Weise zur Verfügung gestellt. Die Fertigkeiten der direkten Ophthalmoskopie sind hierbei deutlich schneller als die der indirekten Ophthalmoskopie zu erlernen.
Introns of human transfer RNA precursors (pre-tRNAs) are excised by the tRNA splicing endonuclease TSEN in complex with the RNA kinase CLP1. Mutations in TSEN/CLP1 occur in patients with pontocerebellar hypoplasia (PCH), however, their role in the disease is unclear. Here, we show that intron excision is catalyzed by tetrameric TSEN assembled from inactive heterodimers independently of CLP1. Splice site recognition involves the mature domain and the anticodon-intron base pair of pre-tRNAs. The 2.1-Å resolution X-ray crystal structure of a TSEN15–34 heterodimer and differential scanning fluorimetry analyses show that PCH mutations cause thermal destabilization. While endonuclease activity in recombinant mutant TSEN is unaltered, we observe assembly defects and reduced pre-tRNA cleavage activity resulting in an imbalanced pre-tRNA pool in PCH patient-derived fibroblasts. Our work defines the molecular principles of intron excision in humans and provides evidence that modulation of TSEN stability may contribute to PCH phenotypes.
High precision measurement of the radiative capture cross section of 238U at the n_TOF CERN facility
(2017)
The importance of improving the accuracy on the capture cross-section of 238U has been addressed by the Nuclear Energy Agency, since its uncertainty significantly affects the uncertainties of key design parameters for both fast and thermal nuclear reactors. Within the 7th framework programme ANDES of the European Commission three different measurements have been carried out with the aim of providing the 238U(n,γ) cross-section with an accuracy which varies from 1 to 5%, depending on the energy range. Hereby the final results of the measurement performed at the n_TOF CERN facility in a wide energy range from 1 eV to 700 keV will be presented.
Neutron-induced fission cross sections of 238U and 235U are used as standards in the fast neutron region up to 200 MeV. A high accuracy of the standards is relevant to experimentally determine other neutron reaction cross sections. Therefore, the detection effciency should be corrected by using the angular distribution of the fission fragments (FFAD), which are barely known above 20 MeV. In addition, the angular distribution of the fragments produced in the fission of highly excited and deformed nuclei is an important observable to investigate the nuclear fission process.
In order to measure the FFAD of neutron-induced reactions, a fission detection setup based on parallel-plate avalanche counters (PPACs) has been developed and successfully used at the CERN-n_TOF facility. In this work, we present the preliminary results on the analysis of new 235U(n,f) and 238U(n,f) data in the extended energy range up to 200 MeV compared to the existing experimental data.
The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points.
Background: Despite advances in treatment of patients with non-small cell lung cancer, carriers of certain genetic alterations are prone to failure. One such factor frequently mutated, is the tumor suppressor PTEN. These tumors are supposed to be more resistant to radiation, chemo- and immunotherapy.
Results: We demonstrate that loss of PTEN led to altered expression of transcriptional programs which directly regulate therapy resistance, resulting in establishment of radiation resistance. While PTEN-deficient tumor cells were not dependent on DNA-PK for IR resistance nor activated ATR during IR, they showed a significant dependence for the DNA damage kinase ATM. Pharmacologic inhibition of ATM, via KU-60019 and AZD1390 at non-toxic doses, restored and even synergized with IR in PTEN-deficient human and murine NSCLC cells as well in a multicellular organotypic ex vivo tumor model.
Conclusion: PTEN tumors are addicted to ATM to detect and repair radiation induced DNA damage. This creates an exploitable bottleneck. At least in cellulo and ex vivo we show that low concentration of ATM inhibitor is able to synergise with IR to treat PTEN-deficient tumors in genetically well-defined IR resistant lung cancer models.