This paper presents the results of the analysis of data from the BTN-Neutron space experiment carried out onboard the Russian module Zvezda, which is part of the
International Space Station
. The ...long observation period from 2008 to 2019 covers the end of the 23rd and almost all of the 24th solar cycle. This made it possible to estimate the amplitude of long-period variations of the neutron background outside the
ISS
due to solar modulation of galactic cosmic rays. For equatorial regions with a high geomagnetic-cutoff index, it does not exceed 10%, while the neutron background changes by almost 1.5–2 times in high-latitude regions around the Earth’s magnetic poles and the South Atlantic Magnetic Anomaly. For the periods of minimum and maximum solar activity within the 24th solar cycle, according to the BTN-Neutron experiment, maps of the distribution of the neutron-component power were constructed and the average neutron-dose rates that the cosmonauts could receive during these periods were estimated. It was shown that, for maximum and minimum solar activity, the average neutron dose rate varies from 25 to 35 µSv/day for neutrons with energies below 15 MeV.
Activated effector T (TE) cells augment anabolic pathways of metabolism, such as aerobic glycolysis, while memory T (TM) cells engage catabolic pathways, like fatty acid oxidation (FAO). However, ...signals that drive these differences remain unclear. Mitochondria are metabolic organelles that actively transform their ultrastructure. Therefore, we questioned whether mitochondrial dynamics controls T cell metabolism. We show that TE cells have punctate mitochondria, while TM cells maintain fused networks. The fusion protein Opa1 is required for TM, but not TE cells after infection, and enforcing fusion in TE cells imposes TM cell characteristics and enhances antitumor function. Our data suggest that, by altering cristae morphology, fusion in TM cells configures electron transport chain (ETC) complex associations favoring oxidative phosphorylation (OXPHOS) and FAO, while fission in TE cells leads to cristae expansion, reducing ETC efficiency and promoting aerobic glycolysis. Thus, mitochondrial remodeling is a signaling mechanism that instructs T cell metabolic programming.
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•TM cells have fused mitochondria while TE cells have fissed mitochondria•Mitochondrial fusion protein Opa1 is required for TM cells and not TE cells•Enforcing fusion improves adoptive cellular immunotherapy against tumors•Cristae remodeling via fusion/fission signals metabolic adaptations in T cells
The fate of T cells is in the shape of their mitochondria: remodeling mitochondrial cristae via fusion/fission instructs metabolic adaptations in T cells and can be modulated to enhance antitumor immunity.
Space nuclear planetology experiments play significant role in the studies of planetary surface composition and volatiles distribution. To determine concentration of major rockforming elements and ...volatiles, one needs to perform model-dependent deconvolution and interpretation of experimental data. This model should completely simulate all environments and experimental conditions influencing neutron production and transport an also including finite lifetime of neutron. The existing Monte Carlo codes are extremely useful for complicated geometry simulations where time-dependent and wide-energy-range solutions are required. However, they usually do not include or include in very simplified way the gravitational field description appropriate for the simulation of neutron propagation on planetary scales. We have proposed an approach useful for surface-to-orbit transport simulations where neutron lifetime and planetary gravitational field are taken into account. The discussion how gravity force and finite neutron lifetime may influence the spectral and angular neutron distributions at different spacecraft altitudes is presented. The obtained results are implemented to the detection of hydrogen-bearing compounds in the lunar regolith. As a good example we used experimental data from LEND/LRO to evaluate how insertion of neutron finite lifetime and lunar gravitational field in numerical model of experiment may influence on the interpretation of measurements made by different LEND neutron detectors.
•The gravity and finite lifetime need to be accounted for the neutron flux modelling.•This accounting most important for low energy neutrons and large planets.•Precise estimation of volatiles is impossible without these effects accounting.•These effects are less important for collimated neutron detectors of LEND.
Several space experiments are planned for probing the soil composition of the Moon and Mars onboard Luna 25, Luna 27, and ExoMars 2020 landers using instruments of the ADRON series. The method of ...active neutron and gamma ray logging, the main goals and objectives of these experiments, the content of the equipment, and the design and electronics of these instruments are described.
The laboratory demonstration of the space experiment was conducted at Joint Institute for Nuclear Research with a new type of planetary gamma-ray spectrometer (GRS-TCP) suite including a gamma-ray ...detector and a charged particle detector combined in coincidence mode. The proposed GRS prototype can select gamma-ray photons with time tags of charged particles of Galactic cosmic rays (GCR) from a predefined solid angle on the sky. It allows to collect gamma-rays only from a local spot on the irradiated surface under the rover or lander and rejects gamma-ray detections from the surrounding area/spacecraft body significantly improving signal-to-noise ratio. The main objective of this laboratory demonstration was to study the capability of this method to distinguish between local spots with different elemental compositions that could be passed by the rover along its traverse. For this purpose, the soil sample simulants corresponding to the different types of Martian regolith identified by Curiosity rover were created and tested by laboratory measurements. It was experimentally shown that our method of spectroscopy of gamma-rays with tags of charged particles could reliably detect local variations of the planetary regolith.
ABSTRACT We have performed a blind search for a gamma-ray transient of arbitrary duration and energy spectrum around the time of the LIGO gravitational-wave event GW150914 with the six-spacecraft ...interplanetary network (IPN). Four gamma-ray bursts were detected between 30 hr prior to the event and 6.1 hr after it, but none could convincingly be associated with GW150914. No other transients were detected down to limiting 15-150 keV fluences of roughly 5 ×10−8-5 × 10−7 erg cm−2. We discuss the search strategies and temporal coverage of the IPN on the day of the event and compare the spatial coverage to the region where GW150914 originated. We also report the negative result of a targeted search for the Fermi-GBM event reported in conjunction with GW150914.
In this paper we present the results of ground tests performed with a flight model and with industry prototypes of passive and active gamma ray spectrometers with the objective of understanding their ...capability to distinguish the elemental composition of planetary bodies in the solar system. The gamma instrumentation, which was developed for future space missions was used in the measurements at a special ground test facility where a simulant of planetary material was fabricated with a martian-like composition. In this study, a special attention was paid to the gamma lines from activation reaction products generated by a pulsed neutron generator. The instrumentation was able to detect and identify gamma lines attributed to O, Na, Mg, Al, Si, K, Ca and Fe.
High Energy Neutron Detector (HEND) onboard the orbital Mars Odyssey mission and Dynamic Albedo of Neutrons (DAN) onboard the Curiosity rover are measuring neutron albedo of Mars produced by Galactic ...Cosmic Rays (GCR). The numerical simulations of HEND/Odyssey and DAN/MSL and comparison between model predictions and experimental data has been implemented to unfold Mars neutron spectra both on orbit and surface and evaluate biological impact contributed by neutrons. It was found that the maximum neuron equivalent dose rate by neutrons below 10 MeV could be as high as 45 ± 7 μSv per day, which is about 6–7% of the expected charged-particle dose equivalent rate.
•Neutron spectrometers HEND/Odyssey and DAN/MSL were used to study the neutron component of Mars radiation environment.•Numerical modeling was implemented to deconvolve neutron spectra in energy range below 10 MeV.•.Neutron dose equivalent rate at Gale crater was estimated for the different periods of solar cycle.
The laboratory demonstration of a space experiment implementing spectrometry of planetary gamma-rays with tags of Galactic Cosmic Rays (GCR) was conducted at Joint Institute for Nuclear Research. The ...main objective of these efforts was to study the capability of this method to search for heterogeneities in the analog of planetary soil and to compare it with capability of the standard gamma-ray spectroscopy. It was experimentally shown that the method of spectroscopy of gamma-rays with tags demonstrates much higher confidence to search variations of amounts of the most widespread metals, like Al, Fe and Ti, in the planetary regoliths. The numerical simulation of the laboratory experiment shows a very good agreement with observations. It is proved that gamma-ray spectrometry with tags is a perspective method for future space missions to explore the Moon, Mars and another celestial bodies with thin atmosphere or without it.
This paper presents the methods of soil parameter estimation from neutron probing data that are used when processing the data from the DAN experiment on the Martian surface. We discuss the data ...preprocessing steps that enable us to compare experimental data to a Monte-Carlo numerical model, algorithms used to estimate equivalent water and chlorine content for standard soil composition and to dynamically analyse the soil parameters in non-standard cases. We also provide the water and chlorine content estimates and compare them with the SAM experiment data.
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