The German Aerospace Center M-42 radiation detector—A new development for applications in mixed radiation fields

In the last few years, the Biophysics Working Group of the Institute of Aerospace Medicine of the German Aerospace Center (DLR) started the development of a small low power consumption radiation detector system for the measurement of the absorbed dose to be applied in various environments, such as onboard aircraft, in space, and also as a demonstration tool for students. These so called DLR M-42 detectors are based on an electronics design, which can easily be adjusted to the user- and mission-requirements. M-42 systems were already applied for measurements in airplanes, during two MAPHEUS (Materialphysikalische Experimente unter Schwerelosigkeit) rocket missions, and are currently prepared for long term balloon experiments. In addition, they will be part of the dosimetry suite of the upcoming Matroshka AstroRad Radiation Experiment on the NASA Artemis I mission. This paper gives an overview of the design and the testing of the DLR M-42 systems and provides highlighted results from the MAPHEUS campaigns where the detectors were tested for the first time under space flight conditions. Results clearly show that the system design enables independent measurements starting upon rocket launch due to the built-in accelerometer sensors and provides data for the relevant 6 min of μ-gravity as given for the MAPHEUS missions. These 6 min of the μ-gravity environment at altitudes between 100 and 240 km lead to a total absorbed dose of 1.21 ± 0.15 μGy being equivalent to half a day of radiation background measured with the M-42 in the laboratory at DLR, Cologne, Germany

Diminished salivary epidermal growth factor secretion : a link between Sjogren's syndrome and autoimmune gastritis?

Objectives: Healthy human labial salivary glands produce epidermal growth factor (EGF). In Sjogren's syndrome (SS), EGF staining is diminished. SS is also associated with chronic autoimmune corpus gastritis. We therefore hypothesized that EGF secretion would be diminished in SS and that this could affect gastric target cells.Methods: Salivary EGF secretion in SS was compared to that in healthy controls using an enzyme-linked immunosorbent assay (ELISA). EGF receptor (EGFR) immunoreactive cells in the gastric corpus of healthy human subjects were analysed using immunostaining.Results: Salivary secretion of EGF was diminished in SS patients (232.4, range 52.6-618.4, vs. 756.6, range 105.3-1631.6 pg/min, p=0.002). Proton-pump positive parietal cells were mostly EGFR immunoreactive whereas very few pepsinogen I (PGI)-positive cells were EGFR positive.Conclusions: As EGF is relatively acid resistant, salivary gland-derived EGF might participate in an exo/endocrine mode of parietal cell maintenance in the gastric corpus. Deficiency of salivary gland-derived EGF in SS patients may cause impairment of gastric parietal cells resulting in exposure of immunogenic cryptic antigens and loss of immunological self-tolerance.Peer reviewe

Diminished salivary epidermal growth factor secretion : a link between Sjogren's syndrome and autoimmune gastritis?

Objectives: Healthy human labial salivary glands produce epidermal growth factor (EGF). In Sjogren's syndrome (SS), EGF staining is diminished. SS is also associated with chronic autoimmune corpus gastritis. We therefore hypothesized that EGF secretion would be diminished in SS and that this could affect gastric target cells.Methods: Salivary EGF secretion in SS was compared to that in healthy controls using an enzyme-linked immunosorbent assay (ELISA). EGF receptor (EGFR) immunoreactive cells in the gastric corpus of healthy human subjects were analysed using immunostaining.Results: Salivary secretion of EGF was diminished in SS patients (232.4, range 52.6-618.4, vs. 756.6, range 105.3-1631.6 pg/min, p=0.002). Proton-pump positive parietal cells were mostly EGFR immunoreactive whereas very few pepsinogen I (PGI)-positive cells were EGFR positive.Conclusions: As EGF is relatively acid resistant, salivary gland-derived EGF might participate in an exo/endocrine mode of parietal cell maintenance in the gastric corpus. Deficiency of salivary gland-derived EGF in SS patients may cause impairment of gastric parietal cells resulting in exposure of immunogenic cryptic antigens and loss of immunological self-tolerance.Peer reviewe

New AMS 14C dates track the arrival and spread of broomcorn millet cultivation and agricultural change in prehistoric Europe

Broomcorn millet (Panicum miliaceum L.) is not one of the founder crops domesticated in Southwest Asia in the early Holocene, but was domesticated in northeast China by 6000 bc. In Europe, millet was reported in Early Neolithic contexts formed by 6000 bc, but recent radiocarbon dating of a dozen 'early' grains cast doubt on these claims. Archaeobotanical evidence reveals that millet was common in Europe from the 2nd millennium bc, when major societal and economic transformations took place in the Bronze Age. We conducted an extensive programme of AMS-dating of charred broomcorn millet grains from 75 prehistoric sites in Europe. Our Bayesian model reveals that millet cultivation began in Europe at the earliest during the sixteenth century bc, and spread rapidly during the fifteenth/fourteenth centuries bc. Broomcorn millet succeeds in exceptionally wide range of growing conditions and completes its lifecycle in less than three summer months. Offering an additional harvest and thus surplus food/fodder, it likely was a transformative innovation in European prehistoric agriculture previously based mainly on (winter) cropping of wheat and barley. We provide a new, high-resolution chronological framework for this key agricultural development that likely contributed to far-reaching changes in lifestyle in late 2nd millennium bc Europe

Measuring Cosmic Rays with the RadMap Telescope on the International Space Station

The RadMap Telescope is a new radiation-monitoring instrument operating in the U.S. Orbital Segment (USOS) of the International Space Station (ISS). The instrument was commissioned in May 2023 and will rotate through four locations inside American, European, and Japanese modules over a period of about six months. In some locations, it will take data alongside operational, validated detectors for a cross-check of measurements. RadMap’s central detector is a finely segmented tracking calorimeter that records detailed depth-dose data relevant to studies of the radiation exposure of the ISS crew. It is also able to record particle-dependent energy spectra of cosmic-ray nuclei with energies up to several hundred MeV per nucleon. A unique feature of the detector is its ability to track nuclei with omnidirectional sensitivity at an angular resolution of two degrees. In this contribution, we present the design and capabilities of the RadMap Telescope and give an overview of the instrument’s commissioning on the ISS

Variation in the human soluble epoxide hydrolase gene and risk of restenosis after percutaneous coronary intervention

<p>Abstract</p> <p>Background</p> <p>Restenosis represents the major limiting factor for the long-term efficacy of percutaneous coronary intervention (PCI). Several genetic factors involved in the regulation of the vascular system have been described to play a role in the pathogenesis of restenosis. We investigated whether the <it>EPHX2 K55R </it>polymorphism, previously linked to significantly higher risk for coronary heart disease (CHD), was associated with the occurrence of restenosis after PCI. The association with incident CHD should have been confirmed and a potential correlation of the <it>EPHX2 K55R </it>variant to an increased risk of hypertension was analysed.</p> <p>Methods</p> <p>An overall cohort of 706 patients was studied: This cohort comprised of 435 CHD patients who had undergone successful PCI. Follow-up coronary angiography in all patients was performed 6 months after intervention. Another 271 patients in whom CHD had been excluded by coronary angiography served as controls. From each patient EDTA-blood was drawn at the baseline ward round. Genomic DNA was extracted from these samples and genotyping was performed by real-time PCR and subsequent melting curve analysis.</p> <p>Results</p> <p>In CHD patients 6 month follow-up coronary angiography revealed a restenosis rate of 29.4%, classified as late lumen loss as well as lumen re-narrowing ≥ 50%.</p> <p>Statistical analysis showed an equal genotype distribution in restenosis patients and non-restenosis patients (A/A 82.0% and A/G + G/G 18.0% versus A/A 82.1% and A/G + G/G 17.9%). Moreover, neither a significant difference in the genotype distribution of CHD patients and controls nor an association with increased risk of hypertension was found.</p> <p>Conclusion</p> <p>The results of the present study indicate that the <it>EPHX2 K55R </it>polymorphism is not associated with restenosis after PCI, with incidence of CHD, or with an increased risk of hypertension and therefore, can not serve as a predictor for risk of CHD or restenosis after PCI.</p

Fatigue crack initiation in AA2024: A coupled micromechanical testing and crystal plasticity study

A new combined experimental and modelling approach has been developed in order to understand the physical mechanisms that lead to crack nucleation in a polycrystalline aluminium alloy AA2024 undergoing cyclic loading. Four-point bending low-cycle fatigue tests were performed inside the chamber of a scanning electron microscope on specimens with a through-thickness central hole, introduced to localize stresses and strains in a small region on the top surface of the sample. Fatigue crack initiation and small crack growth mechanisms were analyzed through high-resolution scanning electron microscope images, local orientation measurements using electron-back-scattered-diffraction, and local strain measurements using digital image correlation. A crystal plasticity finite element model was developed to simulate the cyclic deformation behaviour of AA2024. Two-dimensional Voronoi-based microstructures were generated, and the material parameters for the constitutive equations (including both isotropic and kinematic hardening) were identified using monotonic and fully reversed cyclic tests. A commonly used fatigue crack initiation criterion found in the literature, the maximum accumulated plastic slip, was evaluated in the crystal plasticity finite element model but could not predict the formation of cracks away from the edge of the hole in the deformed specimens. A new criterion combining 2 parameters: The maximum accumulated slip over each individual (critical) slip system and the maximum accumulated slip over all slip systems were formulated to reproduce the experimental locations of crack nucleation in the microstructure

Orion EM-1 Internal Environment Characterization: The Matroshka AstroRad Radiation Experiment

Presentation Outline: Orion Multipurpose Crew Vehicle (MPCV); Radiation Vest for Astronauts - AstroRad; ISS (International Space Station) Matroshka; Matroshka AstroRad Radiation Experiment (MARE) on Exploration Mission 1 (EM-1)