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Hintergrund: Die Analyse krankheitsspezifischer Kosten gewinnt in einem zunehmend ökonomisch ausgerichteten Gesundheitssystem an Relevanz, wobei vor allem chronische Erkrankungen aufgrund der langen Krankheitsdauer sowie häufiger Hospitalisierung und Arztbesuche von besonderem Interesse sind. Epilepsien stellen eine häufige neurologische Erkrankung dar, welche mit paroxysmal auftretenden epileptischen Anfällen und häufig hiermit assoziierten Verletzungen einhergeht und alle Altersgruppen betrifft.
Ziel: Ziel der Arbeit ist die Aufarbeitung der stationären Behandlungskosten anfallsbedingter Verletzungen sowie die Analyse hinsichtlich relevanter kostenverursachender Faktoren. Mittels alternativer Kalkulation der Versorgungskosten soll zusätzlich der Frage nach potenziellen Vergütungsproblemen im aktuellen DRG-System („diagnosis related groups“) nachgegangen werden.
Methoden: Grundlage dieser monozentrischen, retrospektiven Analyse ist der tatsächliche Erlös der stationären Behandlung von 62 Patienten, die zwischen 01/2010 und 01/2018 im Universitätsklinikum Frankfurt aufgrund von Verletzungen im Rahmen epileptischer Anfälle erfolgte. Die Analyse potenzieller kostenverursachender Faktoren bezog sich auf relevante soziodemographische und klinische Aspekte, die alternative Kalkulation der Versorgungskosten wurde mit gängigen gesundheitsökonomischen Methoden durchgeführt.
Ergebnisse: Der mittlere DRG-Erlös betrug 7408 € (±8993 €, Median 5086 €, Spanne 563–44.519 €), die mittleren kalkulierten Kosten 9423 € (±11.113 €, 5626 €, Spanne 587–49.830 €). Als signifikant kostenverursachender Faktor konnte eine Liegedauer ≥7 Tage (p = 0,014) identifiziert werden. Aufgrund des signifikanten Unterschieds (p < 0,001) zwischen Erlös und kalkulierten Kosten erfolgte eine Analyse nach Faktoren für potenzielle Vergütungsprobleme, welche für eine Aufenthaltsdauer von ≥7 Tagen (p = 0,014) sowie für eine Behandlung auf Intensivstation (p = 0,019) signifikant verblieb.
Schlussfolgerung: Die stationären Versorgungskosten von Patienten mit Frakturen aufgrund epileptischer Anfälle sind hoch und daher gesundheitsökonomisch relevant. Generell scheint die auf Fallpauschalen basierende Vergütung nach G‑DRG die tatsächlichen Kosten zu decken, bei Patienten mit einer langen Liegedauer oder einen Aufenthalt auf Intensivstation können jedoch Vergütungsprobleme bestehen.
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.
Monte Carlo simulations and n-p differential scattering data measured with Proton Recoil Telescopes
(2020)
The neutron-induced fission cross section of 235U, a standard at thermal energy and between 0.15 MeV and 200 MeV, plays a crucial role in nuclear technology applications. The long-standing need of improving cross section data above 20 MeV and the lack of experimental data above 200 MeV motivated a new experimental campaign at the n_TOF facility at CERN. The measurement has been performed in 2018 at the experimental area 1 (EAR1), located at 185 m from the neutron-producing target (the experiment is presented by A. Manna et al. in a contribution to this conference). The 235U(n,f) cross section from 20 MeV up to about 1 GeV has been measured relative to the 1H(n,n)1H reaction, which is considered the primary reference in this energy region. The neutron flux impinging on the 235U sample (a key quantity for determining the fission events) has been obtained by detecting recoil protons originating from n-p scattering in a C2H4 sample. Two Proton Recoil Telescopes (PRT), consisting of several layers of solid-state detectors and fast plastic scintillators, have been located at proton scattering angles of 25.07° and 20.32°, out of the neutron beam. The PRTs exploit the ΔE-E technique for particle identification, a basic requirement for the rejection of charged particles from neutron-induced reactions in carbon. Extensive Monte Carlo simulations were performed to characterize proton transport through the different slabs of silicon and scintillation detectors, to optimize the experimental set-up and to deduce the efficiency of the whole PRT detector. In this work we compare measured data collected with the PRTs with a full Monte Carlo simulation based on the Geant-4 toolkit.
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.
Neutron-induced fission cross sections of isotopes involved in the nuclear fuel cycle are vital for the design and safe operation of advanced nuclear systems. Such experimental data can also provide additional constraints for the adjustment of nuclear model parameters used in the evaluation process, resulting in the further development of fission models. In the present work, the 237Np(n,f) cross section was studied at the EAR2 vertical beam-line at CERN's n_TOF facility, over a wide range of neutron energies, from meV to MeV, using the time-of-flight technique and a set-up based on Micromegas detectors, in an attempt to provide accurate experimental data. Preliminary results in the 200 keV – 14 MeV neutron energy range as well as the experimental procedure, including a description of the facility and the data handling and analysis, will be presented.
Background: The potential anti-cancer effects of mammalian target of rapamycin (mTOR) inhibitors are being intensively studied. To date, however, few randomised clinical trials (RCT) have been performed to demonstrate anti-neoplastic effects in the pure oncology setting, and at present, no oncology endpoint-directed RCT has been reported in the high-malignancy risk population of immunosuppressed transplant recipients. Interestingly, since mTOR inhibitors have both immunosuppressive and anti-cancer effects, they have the potential to simultaneously protect against immunologic graft loss and tumour development. Therefore, we designed a prospective RCT to determine if the mTOR inhibitor sirolimus can improve hepatocellular carcinoma (HCC)-free patient survival in liver transplant (LT) recipients with a pre-transplant diagnosis of HCC. Methods: The study is an open-labelled, randomised, RCT comparing sirolimus-containing versus mTOR-inhibitor-free immunosuppression in patients undergoing LT for HCC. Patients with a histologically confirmed HCC diagnosis are randomised into 2 groups within 4-6 weeks after LT; one arm is maintained on a centre-specific mTOR-inhibitor-free immunosuppressive protocol and the second arm is maintained on a centre-specific mTOR-inhibitor-free immunosuppressive protocol for the first 4-6 weeks, at which time sirolimus is initiated. A 3-year recruitment phase is planned with a 5-year follow-up, testing HCC-free survival as the primary endpoint. Our hypothesis is that sirolimus use in the second arm of the study will improve HCC-free survival. The study is a non-commercial investigator-initiated trial (IIT) sponsored by the University Hospital Regensburg and is endorsed by the European Liver and Intestine Transplant Association; 13 countries within Europe, Canada and Australia are participating. Discussion: If our hypothesis is correct that mTOR inhibition can reduce HCC tumour growth while simultaneously providing immunosuppression to protect the liver allograft from rejection, patients should experience less post-transplant problems with HCC recurrence, and therefore could expect a longer and better quality of life. A positive outcome will likely change the standard of posttransplant immunosuppressive care for LT patients with HCC. (trial registered at www.clinicaltrials.gov: NCT00355862) (EudraCT Number: 2005-005362-36)
Neutron capture on 241Am plays an important role in the nuclear energy production and also provides valuable information for the improvement of nuclear models and the statistical interpretation of the nuclear properties. A new experiment to measure the 241Am(n, γ) cross section in the thermal region and the first few resonances below 10 eV has been carried out at EAR2 of the n_TOF facility at CERN. Three neutron-insensitive C6D6 detectors have been used to measure the neutron-capture gamma cascade as a function of the neutron time of flight, and then deduce the neutron capture yield. Preliminary results will be presented and compared with previously obtained results at the same facility in EAR1. In EAR1 the gamma-ray background at thermal energies was about 90% of the signal while in EAR2 is up to a 25 factor much more favorable signal to noise ratio. We also extended the low energy limit down to subthermal energies. This measurement will allow a comparison with neutron capture measurements conducted at reactors and using a different experimental technique.
Purpose: Epileptic seizures frequently result in distinct physical injuries, fractures, traumatic brain injuries and minor trauma. The aim of this study was to retrospectively determine the frequent injury patterns due to seizure episode and to analyze consecutive acute medical care.
Methods: This retrospective mono-center study was conducted at Frankfurt University Hospital, Frankfurt am Main, Germany between January 2007 and December 2017. Epilepsy patients with seizure-related fractures admitted to the emergency department were identified via a retrospective systematic query in the hospital information system using the ICD-10 German modification codes G40.0–G40.9. Patients with an unclear diagnosis of epilepsy were excluded. Sociodemographic as well as disease specific aspects were analyzed. Descriptive and Kruskal–Wallis one-way analysis of variance were used for statistical analysis.
Results: A total number of 62 epilepsy patients were included. The mean age was 58.1 years. Fractures concerned the upper extremity most frequently (43.5%, n = 20), and 70.0% (14/20) were humerus fractures. Admission to intensive care unit for acute trauma care was necessary in 29.0% patients (n = 18), and surgery in 45.2% patients (n = 28). Twenty-five patients (26.6%) showed clinical or radiological signs of traumatic brain injury. Provoking factors were identified in 20 patients (32.3%), i.e., acute withdrawal or excess of alcohol (n = 15), relevant sleep deprivation (n = 2), and intoxication or withdrawal of other illegal drugs or trivial infect (n = 1 for each) and non-compliance with anti-seizure drugs (n = 1). A decreased T-score (−1.04 ± 1.15) and Z-score (−0.84 ± 0.75) compared to healthy subjects were found.
Conclusion: Fractures in upper extremities, trunk and craniocerebral trauma occur frequently as seizure-induced injuries. Alcohol excess and withdrawal are important provoking factors and should be targeted with preventive measurements to avoid seizure related injuries and accidents.
Background: The photon strength functions (PSFs) and nuclear level density (NLD) are key ingredients for calculation of the photon interaction with nuclei, in particular the reaction cross sections. These cross sections are important especially in nuclear astrophysics and in the development of advanced nuclear technologies.
Purpose: The role of the scissors mode in the M1 PSF of (well-deformed) actinides was investigated by several experimental techniques. The analyses of different experiments result in significant differences, especially on the strength of the mode. The shape of the low-energy tail of the giant electric dipole resonance is uncertain as well. In particular, some works proposed a presence of the E1 pygmy resonance just above 7 MeV. Because of these inconsistencies additional information on PSFs in this region is of great interest.
Methods: The γ-ray spectra from neutron-capture reactions on the 234U, 236 U, and 238 U nuclei have been measured with the total absorption calorimeter of the n_TOF facility at CERN. The background-corrected sum-energy and multi-step-cascade spectra were extracted for several isolated s-wave resonances up to about 140 eV.
Results: The experimental spectra were compared to statistical model predictions coming from a large selection of models of photon strength functions and nuclear level density. No combination of PSF and NLD models from literature is able to globally describe our spectra. After extensive search we were able to find model combinations with modified generalized Lorentzian (MGLO) E1 PSF, which match the experimental spectra as well as the total radiative widths.
Conclusions: The constant temperature energy dependence is favored for a NLD. The tail of giant electric dipole resonance is well described by the MGLO model of the E1 PSF with no hint of pygmy resonance. The M1 PSF must contain a very strong, relatively wide, and likely double-resonance scissors mode. The mode is responsible for about a half of the total radiative width of neutron resonances and significantly affects the radiative cross section.
Study of the photon strength functions and level density in the gamma decay of the n + 234U reaction
(2019)
The accurate calculations of neutron-induced reaction cross sections are relevant for many nuclear applications. The photon strength functions and nuclear level densities are essential inputs for such calculations. These quantities for 235U are studied using the measurement of the gamma de-excitation cascades in radiative capture on 234U with the Total Absorption Calorimeter at n_TOF at CERN. This segmented 4π gamma calorimeter is designed to detect gamma rays emitted from the nucleus with high efficiency. This experiment provides information on gamma multiplicity and gamma spectra that can be compared with numerical simulations. The code DICEBOXC is used to simulate the gamma cascades while GEANT4 is used for the simulation of the interaction of these gammas with the TAC materials. Available models and their parameters are being tested using the present data. Some preliminary results of this ongoing study are presented and discussed.