The quantification of the effects of space radiation for manned spaceflight can be approximated by nanodosimetric measurements. For the development of nanodosimetric detectors, a Monte Carlo model ...for ion mobility and diffusion for characteristic electric fields is presented.
This model can be used to describe the interactions of ions in their parent gas based solely on commonly known input parameters, such as the ionization potential, kinetic diameter, molar mass, and polarizability of the gas. A model for approximating the resonant charge exchange cross section has been proposed, requiring only the ionization energy and mass of the parent gas as input parameters. The method proposed in this work was tested against experimental drift velocity data for a wide range of gases (helium, neon, nitrogen, argon, krypton, carbon monoxide, carbon dioxide, oxygen, propane). The transverse diffusion coefficients were compared to experimental values for helium, nitrogen, neon, argon, and propane gas.
With the Monte Carlo code and resonant charge exchange cross section approximation model presented in this work, it is now possible to calculate an estimate of the drift velocities, transverse diffusion, and thus the ion mobility of ions in their parent gas. This is essential for further nanodosimetric detector development, as those parameters are often not well known for the gas mixtures used in nanodosimetry.
Nanodosimetry uses physical quantities based on ionization cluster size distributions to model the biological effectiveness of different radiation qualities. A nanodosimetric detector in operation is ...the FIRE (Frequency of Ion Registration) detector, but further design optimization of the detector is required. The simulations presented in this work will help guide future developments of the detector.
Within the FIRE detector, the produced ions drift towards a dielectric plate hole, within which they are strongly accelerated towards the cathode and produce an electron avalanche through impact ionization. The electron avalanche is measured at the signal readout. COMSOL Multiphysics was used to calculate the electrostatic fields and Garfield＋＋ was used to simulate ion drift trajectories and electron avalanche formation employing Monte Carlo methods.
The dependency of electron avalanche formation on experimental parameters, such as pressure or electric field configuration, was studied and compared to experimental results. Based on the funneling effect ions experience within the drift region, a calculation method for obtaining an optimized hole pitch for future multi-hole detector designs was presented. The results presented in this work offer valuable insights into the inner workings of the FIRE detector, as well as make clarify how different experimental parameters influence signal creation.
One goal of nanodosimetry is to determine statistical quantities of ionization distributions in nanometric volumes. It is hypothesized here that these quantities are related to the initial biological ...damages in DNA from ionizations. Thus nanodosimetric quantities will potentially complement or replace the concept of RBE-weighted absorbed dose and hence they could be applied in treatment planning systems, risk assessments for radiation protection and space radiation. The development of a compact and portable nanodosimeter detector available for clinical routine is a significant step towards that goal. We present extensive measurements to characterize the performance of the FIRE (Frequency of Ion REgistration) nanodosimeter detector. It operates on similar principles like the Gas Electron Multiplier (GEM). Contrary to GEMs the FIRE detector registers positive ions instead of electrons and operates at low pressures of 0.5 Torr to 2.5 Torr. In addition, the FIRE nanodosimeter capitalizes on the usage of a resistive cathode in order to suppress discharges. Moreover, the geometry of the FIRE detector is adapted to the low pressure by enlarging the typical dimensions of a GEM foil by two orders of magnitude.
The authors present two configurations of the compact FIRE nanodosimetry detector. The resistivities of the two configurations differ by six orders of magnitude. The lower resistivity should allow for faster removal of the charges attached to the wall inside the hole channel. Measurements of mean number of ions produced by 5MeV alpha particles in low pressure propane gas, mean number of dark counts, the ion arrival time, and the mean avalanche charge are presented. The dependency of these parameters on acceleration voltage, drift voltage, pressure and hole diameter were investigated.
Abstract
Idiopathic pulmonary fibrosis (IPF) is a fatal disease with limited treatment options. In this study, we focus on the properties of airway basal cells (ABC) obtained from patients with IPF ...(IPF-ABC). Single cell RNA sequencing (scRNAseq) of bronchial brushes revealed extensive reprogramming of IPF-ABC towards a KRT17
high
PTEN
low
dedifferentiated cell type. In the 3D organoid model, compared to ABC obtained from healthy volunteers, IPF-ABC give rise to more bronchospheres, de novo bronchial structures resembling lung developmental processes, induce fibroblast proliferation and extracellular matrix deposition in co-culture. Intratracheal application of IPF-ABC into minimally injured lungs of Rag2
−/−
or NRG mice causes severe fibrosis, remodeling of the alveolar compartment, and formation of honeycomb cyst-like structures. Connectivity MAP analysis of scRNAseq of bronchial brushings suggested that gene expression changes in IPF-ABC can be reversed by SRC inhibition. After demonstrating enhanced SRC expression and activity in these cells, and in IPF lungs, we tested the effects of saracatinib, a potent SRC inhibitor previously studied in humans. We demonstrate that saracatinib modified in-vitro and in-vivo the profibrotic changes observed in our 3D culture system and novel mouse xenograft model.
The incidence of wound infections after percutaneous endoscopic gastrostomy (PEG) varies widely in recent studies. The present study systematically investigates the underlying risk factors for the ...development of wound infections in a large cohort of patients over a long-term follow-up period.
A retrospective cohort study of patients undergoing PEG insertion using either the pull or push technique was conducted and patients followed up for 3 years. Tube-related wound infections were identified, and pathogens regularly cultured from wound swabs. Adjusted analysis was performed via univariate and multivariate logistic regression analysis.
616 patients were included in this study. A total of 25% percent of patients developed wound infections upon PEG tube insertion and 6.5% showed recurrent infections. Nicotine abuse (
= 0.01), previous ischemic stroke (
= 0.01) and head and neck cancer (
< 0.001) showed an increased risk for wound infection after PEG placement. Moreover, radio-chemotherapy was associated with the occurrence of wound infections (
< 0.001). Infection rates were similar between pull and push cohorts. The most common bacterial pathogen detected was Enterobacterales (19.2%).
,
and
were frequently detected in recurrent infection (14.2%, 11.4% and 9.6%, respectively). Antibiotic prophylaxis showed no effect on infection rates.
Wound infections after PEG placement are common and occasionally occur as recurrent infections. There is potential for improvement in everyday clinical practice, particularly regarding antibiotic prophylaxis in accordance with guidelines.
The Near-Earth asteroids (NEAs) may be the most promising targets for resources to be used for space manufacturing. Metals, semiconductors and volatiles from asteroids can be used for production of ...propellant, space constructions and life-support of crewed missions. An assessment of accessible resources and selection of best asteroids-candidates implies a mission analysis together with a compositional data. The ECOCEL database is a web-based tool developed at ISAE-SUPAERO for selection of asteroids-candidates for future space mining missions. The database contains 326 NEAs. For each object, the database includes (i) one-way and round-trip rendezvous mission opportunities computed for 2025–2050 launch period, and (ii) estimated composition inferred from spectral classification and meteorite analogs. The web-application enables searching for suitable target asteroids while specifying mission constraints. In addition, the ECOCEL tool provides a visualisation of compositional data for the entire sample of asteroids.
•Near-Earth asteroids may be the most promising targets for space resources.•ECOCEL is a web-based tool designed for asteroid mission analysis.•The ECOCEL database includes data on one-way and round-trip rendezvous missions.•ECOCEL tools provide a visualisation of asteroids compositional data.
Idiopathic pulmonary fibrosis (IPF) is a fatal disease with limited treatment options. In this study, we focus on the properties of airway basal cells (ABC) obtained from patients with IPF (IPF-ABC). ...Single cell RNA sequencing (scRNAseq) of bronchial brushes revealed extensive reprogramming of IPF-ABC towards a KRT17
PTEN
dedifferentiated cell type. In the 3D organoid model, compared to ABC obtained from healthy volunteers, IPF-ABC give rise to more bronchospheres, de novo bronchial structures resembling lung developmental processes, induce fibroblast proliferation and extracellular matrix deposition in co-culture. Intratracheal application of IPF-ABC into minimally injured lungs of Rag2
or NRG mice causes severe fibrosis, remodeling of the alveolar compartment, and formation of honeycomb cyst-like structures. Connectivity MAP analysis of scRNAseq of bronchial brushings suggested that gene expression changes in IPF-ABC can be reversed by SRC inhibition. After demonstrating enhanced SRC expression and activity in these cells, and in IPF lungs, we tested the effects of saracatinib, a potent SRC inhibitor previously studied in humans. We demonstrate that saracatinib modified in-vitro and in-vivo the profibrotic changes observed in our 3D culture system and novel mouse xenograft model.
Kooperative Informationsinfrastrukturen als Chance und Herausforderung zu diesem Thema werden die Beiträge für die Festschrift für Thomas Bürger zum 65. Geburtstag zusammengestellt. Mehr als 40 ...Beiträge von renommierten Fachwissenschaftlern und Bibliothekaren geben einen aktuellen Überblick.
Dès ses débuts, l’État soviétique entend remplacer le Russe du passé par un « homme nouveau », indispensable pour que se concrétise le projet bolchevik : créer un « monde nouveau », avec des rapports ...politiques, économiques, sociaux et même humains, fondamentalement modifiés. L’Homme nouveau est donc censé être, à la fois, le moyen, la condition, le résultat et le témoignage des changements entrepris. Or, c’est aux arts et à la culture que sont confiées les tâches de représenter cet Homme nouveau et, surtout, de le créer en « rééduquant » – tel était le terme employé – les ex-citoyens de l’Empire qui pouvaient l’être, les autres étant écartés d’une manière ou d’une autre. Après la mort de Staline (1953), le discours officiel reste inchangé pour l’essentiel, mais l’image du Soviétique dans les œuvres littéraires et artistiques, y compris celles autorisées par la censure, se modifie très nettement. En outre, de plus en plus de Soviétiques tentent, par l’art et la culture, d’échapper aux règles trop strictes encadrant la vie sociale. La culture se fait double, voire triple ; plus que jamais, elle multiplie les codes, les doubles sens, l’implicite. Les œuvres d’art et leur réception, des convictions et des goûts évoluent et se complexifient, derrière les slogans officiels rabâchés et les affiches de propagande auxquelles plus grand monde ne prête attention. Un processus de déconstruction de l’Homme nouveau s’observe, tandis que des mythes s’effritent. Et ces évolutions expliquent aussi pourquoi l’URSS n’a pas survécu à cinq années de Perestroïka.
Dès ses débuts, l’État soviétique entend remplacer le Russe du passé par un « homme nouveau », indispensable pour que se concrétise le projet bolchevik : créer un « monde nouveau », avec des rapports ...politiques, économiques, sociaux et même humains, fondamentalement modifiés. L’Homme nouveau est donc censé être, à la fois, le moyen, la condition, le résultat et le témoignage des changements entrepris. Or, c’est aux arts et à la culture que sont confiées les tâches de représenter cet Homme nouveau et, surtout, de le créer en « rééduquant » – tel était le terme employé – les ex-citoyens de l’Empire qui pouvaient l’être, les autres étant écartés d’une manière ou d’une autre. Après la mort de Staline (1953), le discours officiel reste inchangé pour l’essentiel, mais l’image du Soviétique dans les œuvres littéraires et artistiques, y compris celles autorisées par la censure, se modifie très nettement. En outre, de plus en plus de Soviétiques tentent, par l’art et la culture, d’échapper aux règles trop strictes encadrant la vie sociale. La culture se fait double, voire triple ; plus que jamais, elle multiplie les codes, les doubles sens, l’implicite. Les œuvres d’art et leur réception, des convictions et des goûts évoluent et se complexifient, derrière les slogans officiels rabâchés et les affiches de propagande auxquelles plus grand monde ne prête attention. Un processus de déconstruction de l’Homme nouveau s’observe, tandis que des mythes s’effritent. Et ces évolutions expliquent aussi pourquoi l’URSS n’a pas survécu à cinq années de Perestroïka.
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