Ray Exposure Research Articles

Pairing relations within CO3 chondrites recovered at the Dominion Range and Miller Range, Transantarctic mountains: Constraints from chondrule olivines, noble gas, and H, C, N bulk and isotopic compositions

AbstractThe Dominion Range (DOM) and Miller Range (MIL) dense collection areas (DCAs) have yielded more than 20 and 200 CO3 chondrites (carbonaceous chondrites of the Ornans chemical group), respectively, over multiple field seasons. Several samples have exhibited primitive characteristics and have been the focus of interest. With so many CO3s recovered from this area, a natural question is if there are multiple pairing groups (where pairing refers to two or more meteorites that are part of a single fall) and if there is additional primitive material that would interest the meteorite community. This comprehensive study looks at all samples using several approaches: field and macroscopic observations; magnetic susceptibility; Cr in ferroan olivine; bulk elemental and isotopic analysis of H, C, N, and noble gas analyses to determine cosmic ray exposure (CRE) ages. Magnetic susceptibilities (measured as logχ) for all samples correlate with their type II (i.e., FeO‐rich) olivine Cr contents, with the most primitive CO3s (3.00) have logχ values near 5, while the higher grade CO3s have logχ values as low as 4.17. Altogether, there appear to be two distinct CO3 pairing groups and five other unpaired CO3s recovered at the Dominion Range: (a) the main DOM 08004 pairing group (16 specimens with a CRE age of 10–16 Ma), (b) the DOM 08006 group (2 specimens incl. DOM 10847 with a CRE age of 25 Ma), (c) DOM 14359 with a CRE age of 6 Ma, (d) DOM 18070 with a CRE age of 8 Ma (these two samples have similar ages but distinct trapped 20Ne contents), (e) DOM 10900 with a CRE age of 5.5 Ma, (f) DOM 18286 (with a CRE age of ~59 Ma), and (g) DOM 19034 (with a CRE age of ~43 Ma). There are three distinct age groupings of 3.00–3.05 COs, highlighting the diverse pristine CO3 materials present in the DOM area. There is one large MIL pairing group (MIL 07099; n = 199; 9–14 Ma CRE age where measured) and one smaller pairing group with distinctly lower Cr2O3 in type II olivines (8 samples of unknown CRE age), and five unpaired or unique CO3s. Notably, the large DOM and MIL pairing groups have 9–16 Ma exposure ages that could have been delivered in a single large fall event spanning ~200 km, two separate falls that were ejection paired, or two separate falls from two separate ejections. Finally, we recommend reclassifying several CO3 to CM2 based on new data and that from previous studies.

Tissue-specific dose equivalents of secondary mesons and leptons during galactic cosmic ray exposures for mars exploration

During a human mission to Mars, astronauts would be continuously exposed to galactic cosmic rays (GCR) consisting of high energy protons and heavier ions coming from outside our solar system. Due to their high energy, GCR ions can penetrate spacecraft and space habitat structures, directly reaching human organs. Additionally, they generate secondary particles when interacting with shielding materials and human tissues. Baryon secondaries have been the focus of many previous studies, while meson and lepton secondaries have been considered to a much lesser extent. In this work, we focus on assessing the tissue-specific dose equivalents and the effective dose for males of secondary mesons and leptons for the interplanetary cruise phase and the surface phase on Mars. We also provide the energy distribution of the secondary pions in each human organ since they are dominant compared to other mesons and leptons. For this calculation, the PHITS3.27 Monte Carlo simulation toolkit is used to compute the energy spectra of particles in organs in a realistic human phantom. Based on the simulation data, the dose equivalent has been estimated with radiation quality factors in ICRP Publication 60 and in the latest NASA Space Cancer Risk model (NSCR-2022). The effective dose is then assessed with the tissue weighting factors in ICRP Publication 103 and in the NSCR model, separately. The results indicate that the contribution of secondary mesons and leptons to the total effective dose is 6.1 %, 9.1 %, and 11.3 % with the NSCR model in interplanetary space behind 5, 20, and 50 g/cm2 aluminum shielding, respectively, with similar values using the ICRP model. The outcomes of this work lead to an improved understanding of the potential health risks induced by secondary particles for exploration missions to Mars and other destinations.

Q-switched 1064 nm Nd: YAG laser restores skin photoageing by activating autophagy by TGFβ1 and ITGB1.

Excessive ultraviolet B ray (UVB) exposure to sunlight results in skin photoageing. Our previous research showed that a Q-switched 1064 nm Nd: YAG laser can alleviate skin barrier damage through miR-24-3p. However, the role of autophagy in the laser treatment of skin photoageing is still unclear. This study aims to investigate whether autophagy is involved in the mechanism of Q-switched 1064 nm Nd: YAG in the treatment of skin ageing. Invitro, primary human dermal fibroblast (HDF) cells were irradiated with different doses of UVB to establish a cell model of skin photoageing. Invivo, SKH-1 hairless mice were irradiated with UVB to establish a skin photoageing mouse model and irradiated with laser. The oxidative stress and autophagy levels were detected by western blot, immunofluorescence and flow cytometer. String was used to predict the interaction protein of TGF-β1, and CO-IP and GST-pull down were used to detect the binding relationship between TGFβ1 and ITGB1. Invitro, UVB irradiation reduced HDF cell viability, arrested cell cycle, induced cell senescence and oxidative stress compared with the control group. Laser treatment reversed cell viability, senescence and oxidative stress induced by UVB irradiation and activated autophagy. Autophagy agonists or inhibitors can enhance or attenuate the changes induced by laser treatment, respectively. Invivo, UVB irradiation caused hyperkeratosis, dermis destruction, collagen fibres reduction, increased cellular senescence and activation of oxidative stress in hairless mice. Laser treatment thinned the stratum corneum of skin tissue, increased collagen synthesis and autophagy in the dermis, and decreased the level of oxidative stress. Autophagy agonist rapamycin and autophagy inhibitor 3-methyladenine (3-MA) can enhance or attenuate the effects of laser treatment on the skin, respectively. Also, we identified a direct interaction between TGFB1 and ITGB1 and participated in laser irradiation-activated autophagy, thereby inhibiting UVB-mediated oxidative stress further reducing skin ageing. Q-switched 1064 nm Nd: YAG laser treatment inhibited UVB-induced oxidative stress and restored skin photoageing by activating autophagy, and TGFβ1 and ITGB1 directly incorporated and participated in this process.

Chondrules from the ordinary chondrite Itawa Bhopji (L3-5): Noble gases and nitrogen

Noble gases and nitrogen compositions are investigated in chondrules of Itawa Bhopji (L3-5) chondrite. Single chondrule and bunch of chondrules were analysed in this work. Isotopic ratios of noble gases in chondrules indicate mixture of Q-HL-SW and cosmogenic. The cosmic ray exposure age of the chondrules using 21Ne are 30.0 ± 2.3 and 25.9 ± 2.5 Ma. No excess cosmic ray exposure (CRE) age observed in the chondrules from that of bulk aliquot of dark lithology. The trapped nitrogen signature, δ15Nt in the chondrules, is +15.8 ± 2.2‰ (bunch of chondrules) and +15.1 ± 2.3‰ (single chondrule). Trapped nitrogen isotopic signature in chondrules differs from dark and light lithology of the meteorite and it is also distinct from metal separates. Trapped nitrogen composition in chondrules differs than Q-phase, solar wind (SW) and HL components. This implies that chondrules in Itawa Bhopji (L3-5) chondrite composed of isotopically distinct component than any of the known reservoir. Distinct trapped nitrogen isotopic signatures in the constituents of a meteorite indicates their formation at various places with the heliocentric distance. The abundance of nitrogen in chondrules is 6.14 ± 0.51 ppm (bunch) and 5.71 ± 0.48 ppm (single). Radiogenic 129Xe from the decay of 129I was observed in chondrules, indicative of their formation in early solar system.

The activity of of vitexicarpin and artemetin in inhibiting hyperpigmentation: an in silico study

Hyperpigmentation, characterized by increased skin darkening, is primarily attributed to augmented melanin production, often exacerbated by UV ray exposure. Inhibiting melanogenesis enzymes, such as tyrosinase, tyrosinase-related protein 1, and d-dopachrome tautomerase, is a recognized strategy for managing hyperpigmentation. Flavonoid compounds, namely vitexicarpin and artemetin, have emerged as potential antihyperpigmentation agents. This study explores the inhibitory capabilities of vitexicarpin and artemetin on melanogenesis enzymes through in silico molecular docking. The process involved optimization of test compounds using HyperChem 8, target protein preparation with Chimera 1.11, method validation, and docking employing AutoDockTools 1.5.6, which integrates Autodock4 and Autogrid4 programs. The validity of the molecular docking method was confirmed with an RMSD value of ≤3 Å. The findings demonstrate that vitexicarpin and artemetin exhibit higher affinity towards tyrosinase, tyrosinase-related protein 1, and d-dopachrome tautomerase than the native ligands. Interaction models between the compounds and target proteins include hydrogen bonds, Van der Waals forces, hydrophobic interactions, and electrostatic bonds, with the most visually identifiable hydrogen bonds. These results suggest that vitexicarpine and artemetin have promising potential as antihyperpigmentation agents by inhibiting melanogenesis enzymes, as evidenced by the molecular docking approach.

Simulated galactic cosmic ray exposure activates dose-dependent DNA repair response and down regulates glucosinolate pathways in arabidopsis seedlings.

Outside the protection of Earth's magnetic field, organisms are constantly exposed to space radiation consisting of energetic protons and other heavier charged particles. With the goal of crewed Mars exploration, the production of fresh food during long duration space missions is critical for meeting astronauts' nutritional and psychological needs. However, the biological effects of space radiation on plants have not been sufficiently investigated and characterized. To that end, 10-day-old Arabidopsis seedlings were exposed to simulated Galactic Cosmic Rays (GCR) and assessed for transcriptomic changes. The simulated GCR irradiation was carried out in the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Lab (BNL). The exposures were conducted acutely for two dose points at 40 cGy or 80 cGy, with sequential delivery of proton, helium, oxygen, silicon, and iron ions. Control and irradiated seedlings were then harvested and preserved in RNAlater at 3 hrs post irradiation. Total RNA was isolated for transcriptomic analyses using RNAseq. The data revealed that the transcriptomic responses were dose-dependent, with significant upregulation of DNA repair pathways and downregulation of glucosinolate biosynthetic pathways. Glucosinolates are important for plant pathogen defense and for the taste of a plant, which are both relevant to growing plants for spaceflight. These findings fill in knowledge gaps of how plants respond to radiation in beyond-Earth environments.

Age estimation and boulder population analysis of the West crater at Apollo 11 landing site using Orbiter High Resolution Camera on board Chandrayaan-2 mission

Orbiter High Resolution Camera (OHRC) on-board Chandrayaan-2 had acquired a high-resolution image (∼0.26 m) covering Apollo 11 landing site, showing the Lander Module (LM) along with other small-scale features, such as boulders, etc. In the east of Apollo 11 LM lies the West crater, which has a rich population of boulders spread around it. We studied this boulder distribution around the West crater to estimate the age of the West crater and to understand the aspects related to the impact cratering and space weathering through the analysis of boulder distribution. For this, we identified and mapped >8500 boulders around the West crater using the OHRC image, out of which 6466 boulders (>∼1 m in size) lying within 1–5 crater radius were used for further analysis. For estimating the age of the West crater, we applied various methods based on crater morphology, boulder distributions and Diviner Rock Abundance. The age was estimated to be in the range of 80 Ma to 120 Ma with the most probable age close to 100 Ma, the same as that expected from the cosmic ray exposure dating. Boulder distribution around the West crater was found to be highly anisotropic with majority of boulders lying in the eastern to north-eastern direction, suggesting an impact at very low angle. Relationship between crater size and largest boulder size also pointed towards primary origin of the West crater. The Height (H) to Diameter (D) ratio is estimated to be ∼0.25 considering all the boulders with diameter ≤ 4m, going up to 0.38 with comparatively poor correlation for boulders with diameter > 4m. The H/D ratio from Apollo mission photos for boulders around Apollo 11 LM is found to be approximately double that of the corresponding measurements from the OHRC image. We also fit a Power law and the Weibull distribution to the cumulative Boulder Size Frequency Distribution (BSFD) curve with Maximum Likelihood (ML) method and Kolmogrov-Smirnoff (KS) statistics. Both fit well with R2 of 0.999, but varying minimum diameter (dKS) of 1.85 m and 1.64 m, respectively. The good fit by Power-law with high slope value (b = 4.61) describes the fragmentation due to the West crater forming impact as complex. However, the higher diameter tail was better explained by the Weibull fit implying sequential fragmentation of boulders with time.

Methodologies for 176Lu-176Hf Analysis of Zircon Grains from the Moon and Beyond.

Zircons are found in extraterrestrial rocks from the Moon, Mars, and some differentiated meteorite parent-bodies. These zircons are rare, often of small size, and have been affected by neutron capture induced by cosmic ray exposure. The application of the 176Lu-176Hf decay system to zircons from planetary bodies such as the Moon can help establish the chronology of large-scale differentiation processes such as the crystallization of the lunar magma ocean. Here, we present methods to measure the isotopic composition of Hf of extraterrestrial zircons dated using ID-TIMS U-Pb after chemical abrasion. We introduce a 2-stage elution scheme to separate Hf from Zr while preserving the unused Zr fraction for future isotopic analysis. The effect of neutron capture is also re-examined using the latest thermal neutron capture cross sections and epithermal resonance integrals. Our tests show that the precision of Hf isotopic analyses is close to what is theoretically attainable. We have tested this method to a limited set of zircon grains from lunar rocks returned by the Apollo missions (lunar soil 14163, fragmental polymict breccia 72275, and clast-rich breccia 14321). The model ages align with previously reported values, but further work is needed to assess the chronology of lunar magma ocean crystallization as only a handful of small zircons (5 zircons from 3 samples) were analyzed, and the precision of the analyses can be improved by measuring more and larger lunar zircon grains.

Neodymium‐142 deficits and samarium neutron stratigraphy of C‐type asteroid (162173) Ryugu

AbstractWe report Nd and Sm isotopic compositions of four samples of Ryugu returned by the Hayabusa2 mission, including “A” (first touchdown) and “C” (second touchdown) samples, and several carbonaceous chondrites to evaluate potential genetic relationships between Ryugu and known chondrite groups and track the cosmic ray exposure history of Ryugu. We resolved Nd and Sm isotopic anomalies in small (<20 ng Nd and Sm) sample sizes via thermal ionization mass spectrometer using 1013 Ω amplifiers. Ryugu samples exhibit resolvable negative μ142Nd values consistent with carbonaceous chondrite values, suggesting that Ryugu is related to the parent bodies of carbonaceous chondrites. Ryugu's negative μ149Sm values are the result of exposure to galactic cosmic rays, as demonstrated by the correlation between 150Sm/152Sm and 149Sm/152Sm ratios that fall along the expected neutron capture correlation line. The neutron fluence calculated in the “A” samples (2.75 ± 1.94 × 1015 n cm−2) is slightly higher compared to the “C” samples (0.95 ± 2.04 × 1015 n cm−2), though overlapping within measurement uncertainty. The Sm results for Ryugu, at this level of precision, thus are consistent with a well‐mixed surface layer at least to the depths from which the “A” and “C” samples derive.

Efek Blueberry (Vaccinium sp.) Terhadap Kelembapan Kulit yang Terpapar Sinar Ultraviolet Akut

Introduction: Maintained skin moisture is an indication of healthy skin. Acute UV exposure can cause sunburn, which is characterized by a loss of moisture in the skin. Polyphenol compounds are one practical approach to protecting the skin from sunburn so that skin moisture is maintained. Blueberries are one of the natural ingredients consists of anthocyanin compounds, which are polyphenols from the flavonoid group.
 Aims: To determine the effect of blueberries on skin moisture exposed to acute ultraviolet rays.
 Methods: Literature study using references in the form of research articles and literature reviews from national and international journals and related books published in the last 10 years. In writing this literature review, 42 references were used which were accessed through Google Scholar, NCBI, Crossref, and Pubmed.
 Results: Blueberries anthocyanins can maintain skin moisture from increased transepidermal water loss (TEWL) due to acute UV ray exposure by reducing the formation of UV stimulated reactive oxygen species (ROS) and lipid peroxidation in keratinocyte cells to maintain the elastic modulus and mechanical properties of keratinocytes as well as can prevent sunburn by reducing the skin's modulation of UV exposure. However, the absorption of anthocyanin compounds in the intestine is so low that taking blueberries orally alone is not enough to achieve good biodistribution.
 Conclusion: Blueberries affect retaining moisture in skin exposed to acute UV rays, so they have the potential to be used as skincare ingredients. However, further research needs to be done, especially to determine the side effects that can be caused and the required extract concentration.

The Golden meteorite fall: Fireball trajectory, orbit, and meteorite characterization

AbstractThe Golden (British Columbia, Canada) meteorite fall occurred on October 4, 2021 at 0534 UT with the first recovered fragment (1.3 kg) landing on an occupied bed. The associated fireball was recorded by numerous cameras permitting reconstruction of its trajectory and orbit. The fireball entered the atmosphere at a 54° angle from the horizontal at a speed of 18 km s−1. The fireball reached a peak brightness of −14, having first become luminous at a height of >84 km and ending at 18 km altitude. Analysis of the infrasonic record of the bolide produced an estimated mass of kg while modeling of the fireball light curve suggests an initial mass near 70 kg. The fireball experienced a major flare near 31 km altitude where more than half its mass was lost in the form of dust and gram‐sized fragments under a dynamic pressure of 3.3 MPa. The strength and fragmentation behavior of the fireball were similar to those reported for other meteorite‐producing fireballs (Borovička et al., 2020). Seven days after the fireball occurred, an additional 0.9 kg fragment was recovered during the second day of dedicated searching guided by initial trajectory and dark flight calculations. Additional searching in the fall and spring of 2021–2022 located no additional fragments. The meteorite is an unbrecciated, low‐shock (S2) ordinary chondrite of intermediate composition, typed as an L/LL5 with a grain density of ~3530 k gm−3, an average bulk density of 3150 kg m−3 and calculated porosity of ~10%. From noble gas measurements, the cosmic ray exposure age is 25 ± 4 Ma while gas retention ages are all >2 Ga. Short‐lived radionuclides and noble gas measurements of the pre‐atmospheric size overlap with estimates from infrasound and light curve modeling producing a preferred pre‐atmospheric mass of 70–200 kg. The orbit of Golden has a high inclination (23.5°) and is consistent with delivery from the inner main belt. The highest probability (60%) of an origin is from the Hungaria group. We propose that Golden may originate among the background S‐type asteroids found interspersed in the Hungaria region. The current collection of 18 L/LL—chondrite orbits shows a strong preference for origins in the inner main belt, suggesting multiple parent bodies may be required to explain the diversity in CRE ages and shock states.

Light noble gases in 11 achondrites: Cosmic ray exposure ages, gas retention ages, and preatmospheric sizes

AbstractWe report light noble gas (He, Ne, and Ar) concentrations and isotopic ratios in 11 achondrites, Tafassasset (unclassified primitive achondrite), Northwest Africa (NWA) 12934 (angrite), NWA 12573 (brachinite), Jiddat al Harasis (JaH) 809 (ureilite), NWA 11562 (ungrouped achondrite), four lodranites (NWA 11901, NWA 7474, NWA 6685, and NWA 6484), NWA 2871 (acapulcoite), and Sahara 02029 (winonaite), most of which have not been previously studied for noble gases. We discuss their noble gas isotopic composition, determine their cosmogenic nuclide content, and systematically calculate their cosmic ray exposure (CRE) and gas retention ages. In addition, we estimate their preatmospheric radii and preatmospheric masses based on the shielding parameter (22Ne/21Ne)cos. None of the studied meteorites shows evidence of contribution from solar cosmic rays (SCRs). JaH 809 and NWA 12934 show evidence of 3He diffusive losses of >90% and 40%, respectively. The winonaite Sahara 02029 has lost most of its noble gases, either during or before analysis. The average CRE age of Tafassasset of ~49 Ma is lower than that reported by Patzer et al. (2003), but is consistent with it within the uncertainties; this confirms that Tafassasset and CR chondrites are not source paired, CR chondrites having CRE ages from 1 to 25 Ma (Herzog & Caffee, 2014). The ureilite JaH 809 has a CRE age of ~5.4 Ma, which falls into the typical range of exposure ages for ureilites; the angrite NWA 12934 has a CRE age of ~49 Ma, which is within the main range of exposure ages reported for angrites (0.2–56 Ma). We calculate a CRE age of ~2.4 Ma for the brachinite NWA 12573, which falls into a possible “cluster” in the brachinite CRE age histogram around ~3 Ma. Three lodranites (NWA 11901, NWA 7474, and NWA 6685) have CRE ages higher than the average CRE ages of lodranites measured so far, NWA 11901 and NWA 6685 having CRE ages far higher than the CRE age already reported by Li et al. (2019) on NWA 8118. The measured 40K‐40Ar gas retention ages fit well into established systematics. The gas retention age of Tafassasset is consistent, within respective uncertainties, with that previously calculated by Patzer et al. (2003). Our study indicates that Tafassasset originates from a meteoroid with a preatmospheric radius of ~20 cm, however discordant with the radius of ~85 cm inferred in a previous study (Patzer et al., 2003).

Dynamical feasibility of (3) Juno as a parent body of the H chondrites

We test the hypothesis that (3) Juno is a parent body of the H chondrites with dynamical modeling of an asteroid-family-forming impact and comparison to current observational data. Using a dynamical model that includes the Yarkovsky force on a simulated Juno family and a simplified cosmic ray exposure age model we examine the expected distribution of Juno family members in both the main belt and near-Earth orbits over 300 Myrs and the cosmic ray exposure distribution for fragments exiting the main belt, via the 3:1J, 5:2J, and 8:3J mean motion resonances. We find that the smallest modeled (D<10 m) family members of (3) Juno cannot be directly responsible for the observed H chondrite flux and that the breakup of larger family members creates an CRE distribution that resembles the measured H chondrite CRE distribution but is still unable to adequately explain the significant number of H chondrites with CRE ages of 6–8 Myrs. A similar model was performed for the asteroid (6) Hebe, another parent body candidate, and produced a CRE age distribution that is inconsistent with the measured H chondrite CRE ages. We also find from our dynamical models that we can expect <7 km-scale Juno family members in near-Earth orbits in the present day, consistent with the recent discovery of the shock-darkened H chondrite-like asteroid (52768) 1998 OR2.

Geomorphological record of the glacial to periglacial transition from the Bølling–Allerød to the Holocene in the Central Pyrenees: the Lòcampo cirque in the regional context

In the highest tributaries of the Upper Garonne Basin, Central Pyrenees, cirques up to 2600 m a.s.l. were already deglaciated by 15–14 ka. The long‐term deglaciation during Termination‐1 (T‐1) was interrupted by glacial advances within the cirques during the Bølling–Allerød (B‐A) interstadial and the Younger Dryas stadial. The cirques preserve a variety of glacial and periglacial landforms whose chronologies are poorly known. This study is focused on the Lòcampo cirque (42°38′06″N and 0°59′10″E), Upper Garonne Basin, where a detailed geomorphological map and 10Be terrestrial cosmic ray exposure (CRE) dating allowed us to constrain the chrono‐sequence between the glacial and periglacial domains. In the small Lòcampo cirque, a glacier formed a cirque moraine between 2200 and 2300 m a.s.l., which surrounds a relict rock glacier encompassing several transversal ridges. Additionally, longitudinal ridges typically observed in debris‐covered glaciers are preserved between the moraine and the rock glacier. The eight‐sample data set of CRE ages indicates the formation of the cirque moraine during the second half of the B‐A, by 13.2±1.1 ka. Exposure ages from the rock glacier boulders show a range between 13.6±0.9 and 11.9±0.7 ka, which did not allow its formation to be chronologically constrained. Therefore, the environmental evolution following the moraine stabilization could follow the formation of a debris‐covered glacier at the bottom of the Lòcampo cirque, with the subsequent formation of the rock glacier. After the rock glacier formation, its front rapidly ceased at 13.6±0.9 ka, while the upper ridges gradually stabilized until it became definitively relict at 11.9±0.7 ka or afterwards. These results show evidence of the complex glacial to periglacial transition that needs more robust chronological data sets to better understand the role of climate forcing and local topography during the deglaciation in mid‐latitude mountain environments.

In-situ critical current measurements of REBCO coated conductors during gamma irradiation

Rare-earth-barium-copper-oxide (REBCO) coated conductor tapes within next-generation tokamak pilot and power plant magnets will be exposed to broad-spectrum gamma-ray and neutron irradiation concurrently. It has been known since the 1980s that cumulative neutron fluence affects the superconducting properties of REBCO, but the effects of gamma rays are less certain, as are the effects of radiation (of any kind) during current flow. However, the use of superconductors as photon detectors suggests that energetic photons interact directly with the superconducting state, locally destroying superconductivity. Hence, as well as the effect of the overall radiation dose (fluence), the effect of radiation dose rate (flux) on the superconductor’s properties must be quantified to understand how REBCO magnets will perform during fusion magnet operation. In-situ measurements of the self-field critical current at 77 K, of several REBCO coated conductor tapes were performed during Co-60 gamma ray exposure at a dose rate of 86 Gy min−1. Samples were fully submerged in liquid nitrogen throughout the measurements. No change in the critical current of any sample during or after irradiation was observed within standard error. These are the first reported in-situ measurements of critical current during fusion-relevant gamma irradiation. Two samples were irradiated to a further dose of 208 kGy at room temperature and a second round of in-situ measurements was performed. No change in the critical current of these samples was observed within standard error. This corroborates recent studies, but is in conflict with older literature.

Deciphering the Genetic Mechanisms of Salt Tolerance in Sorghum bicolor L.: Key Genes and SNP Associations from Comparative Transcriptomic Analyses.

Sorghum bicolor L. is a vital cereal crop for global food security. Its adaptability to diverse climates make it economically, socially, and environmentally valuable. However, soil salinization caused by climate extremes poses a threat to sorghum. This study aimed to identify candidate salt-tolerant genes and single nucleotide polymorphisms (SNPs) by performing a comparative transcriptome analysis on a mutant sorghum line and its wild type. The mutant line was generated through gamma ray exposure and selection for salt tolerance. Phenotypic measurements were taken, followed by mRNA sequencing and variant calling. In this study, potential genes and non-synonymous SNPs associated with salt tolerance were inferred, including LOC8071970, LOC8067721, LOC110430887, LOC8070256, and LOC8056880. These genes demonstrated notable differences in nsSNPs in comparison to the wild type, suggesting their potential roles in salt tolerance. Additionally, LOC8060874 (cyanohydrin beta-glucosyltransferase) was suggested as a key gene involved in salt tolerance due to its possible role in dhurrin biosynthesis under salt stress. In upcoming research, additional reverse genetics studies will be necessary in order to verify the function of those candidate genes in relation to salt stress. In conclusion, this study underscores the significance of investigating salt tolerance mechanisms and the potential key genes associated with salt tolerance in sorghum. Our findings may provide insights for future breeding strategies aimed at enhancing salinity tolerance and crop productivity.

Systemic Photoprotection in Melanoma and Non-Melanoma Skin Cancer.

Non-melanoma skin cancers (NMSCs), which include basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and actinic keratosis (AK), are the most common cancer diseases in the Caucasian race. If diagnosed late and improperly treated, BCC and SCC can become locally advanced and metastasize. Malignant melanoma (MM) is less frequent but more lethal than NMSC. Given the individual and social burdens of skin cancers, performing an adequate prevention is needed. Ultraviolet (UV) ray exposure is one of the main risk factors for skin cancer. Thus, the first-choice prevention strategy is represented by photoprotection that can be both topical and systemic. The latter consists of the oral administration of molecules which protect human skin against the damaging effects of UV rays, acting through antioxidant, anti-inflammatory, or immunomodulator mechanisms. Although several compounds are commonly used for photoprotection, only a few molecules have demonstrated their effectiveness in clinical trials and have been included in international guidelines for NMSC prevention (i.e., nicotinamide and retinoids). Moreover, none of them have been demonstrated as able to prevent MM. Clinical and preclinical data regarding the most common compounds used for systemic photoprotection are reported in this review, with a focus on the main mechanisms involved in their photoprotective properties.

The Prados del Cervunal morainic complex: Evidence of a MIS 2 glaciation in the Iberian Central System synchronous to the global LGM

The area of Prados del Cervunal (PC) is an intra-morainic topographic depression located at 1800 m asl in the divide or interfluve between Garganta de Gredos and Garganta del Pinar valleys (Central Gredos; Iberian Central System, ICS). Both valleys, along with the adjacent Hoya Nevada, were occupied by glaciers during the Upper Pleistocene, leading to the development of the Prados del Cervunal moraine complexes studied in this work. Using cartographic methods and morphostratigraphic analysis, the three main glacial formations established in the Regional Chrono-Evolutionary Pattern for the ICS, Peripheral Deposits (PD), Principal Moraine (PM) and Internal Deposits (ID), have been identified and mapped in this area. The chronology of these formations has been implemented by Cosmic Ray Exposure (CRE) techniques using 10Be (new data) and 26Cl (previous data, recalculated in this work) in samples from morainic boulders. With these data, the following chrono-evolutionary sequence has been established: (stage 1) local-Maximum Ice Extent (MIE), dated in 25.0 ± 1.4 ka and corresponding to the maximum age obtained in these paleoglaciers; (stage 2) period of oscillations around the MIE, corresponding to the development of the PD Formation between ∼25 ka and ∼21 ka; (stage 3) period of readvance and stabilisation, dated after ∼21 ka (average age obtained for the PD moraines attached to PM moraines) and previous to ∼18 (minimum age obtained for a main crest of the PM formation); and (stage 4) onset of deglaciation dated around to ∼18 ka (average of ages obtained for the first main crest of the ID formation). During the stages of maximum ice expansion, these three glaciers formed an Ice field whose tongues were interconnected on the PC flat by an ice transfluence system (stages 1 and 2, Plateau Glacier Period). In later stages, the ice masses were partitioned, giving rise to valley glaciers and large moraines forming morainic complexes like those of PC (stages 2, 3 and 4, Valley Glaciers Period). The local MIE and onset of deglaciation stages in this area show a good fit with the ages stablished to global level for the global Last Glacial Maximum (LGM) and the onset of the Last Glacial Termination (Termination I). They also show good correlation at local (with other areas of the ICS), peninsular (with other Iberian mountains) and continental (some areas of the Alps and mountains of Central Europe) level. Finally, this evolutionary sequence and its correlations allowed us to adjust and validate some units of the Regional Chrono-Evolutionary Pattern model and propose the Gredos-Pinar-Cabeza Nevada glacial system as benchmark for the glaciation of Marine Isotope Stage (MIS) 2 in the Iberian Peninsula.

Investigating noble gases and nitrogen in Zag (H3-6) and ALH 77216 (L3.7–3.9): The ordinary chondrites with solar type neon and argon

Concentrations and isotopic compositions of noble gases (He, Ne, Ar, Kr, and Xe) and nitrogen in two ordinary chondrites (OCs), Zag (H3-6) and ALH 77216 (L3.7–3.9), are presented. The aim of the study is to examine the cosmic ray exposure history, radiogenic ages and isotopic signatures of trapped gases in them. The results of stepwise heating analyses indicate that light noble gases (He and Ne) are mixture of trapped and cosmic ray produced components. Neon isotopes are enriched from solar wind (SW), while shows a trend towards galactic cosmic ray (GCR) region in both the meteorites. Phase-Q neon is not observed in any of the meteorite. The heavy noble gases Ar, Kr and Xe indicate mixture of Q-HL-SW and cosmogenic. Elemental ratios of trapped 36Ar, 84Kr and 132Xe indicate that noble gases in Zag and ALH 77216 are mixtures of the three components Q, HL and SW. The cosmic-ray exposure (CRE) ages calculated from neon for Zag and ALH 77216 are 5.6 ± 0.3 Ma and 28.5 ± 0.4 Ma, respectively. These ages are within the range typically observed for the respective meteorite types of OCs. Nitrogen isotopes indicate presence of multiple components in both the chondrites. Isotopic signature of trapped nitrogen in both the chondrites is distinct from that of SW, Q and HL, indicating additional source of nitrogen in the meteorites.

Administration Of 30% Robusta Coffee (Coffea canephora) Silverskin Ethyl Acetate Fraction Cream Inhibited The Increase Of MITF Expression And Melanin Amount In The Skin Of Male Adult Guinea Pig (Cavia porcellus) Exposed To Ultraviolet B Ray

Background: Melanin is produced through melanogenesis which involves several molecular processes with microphthalmia-associated transcription factor (MITF) as the main regulator of melanin synthesis. Hyperpigmentation is one of aging sign that happens due to melanin buildup in the skin. Hyperpigmentation can be caused by many factors, and one of the most frequent cause is ultraviolet (UV) ray exposure. Robusta coffee silverskin is a thin layer on a green coffee bean that is detached from the bean through roasting process, and is a waste product of coffee production. However, coffee silverskin contains high amount of phenolic and flavonoid compounds, and is categorized as strong antioxidant. The purpose of this study was to prove that administration of 30% Robusta coffee silverskin ethyl acetate fraction cream inhibited the increase of MITF expression and melanin amount in the skin of male adult guinea pig exposed to UVB ray. Methods: This study used randomized post-test only control group design. Subjects used in this study were healthy male guinea pigs with age ranging from 3-4 months and average weight 300-350g. Total samples used in this study were 36 guinea pigs divided evenly into two groups, Group K that were only exposed to UVB ray, and Group P that were exposed to UVB ray and 30% Robusta coffee silverskin ethyl acetate fraction cream. Total UV ray used during two weeks were 390mJ/cm2. 30% Robusta coffee silverskin ethyl acetate fraction cream was applied twice a day on guinea pigs at the days they were not exposed to UVB ray, and at the days they were exposed to UVB ray, the cream was applied 20 minutes before and 4 hours after the exposure. MITF expression was examined under the microscope with MITF antibody kit, and melanin amount was examined with Masson-Fontana staining. Results: Result of the experiment showed higher MITF expression and melanin amount in the Group K. Comparison analysis with 2 independent samples t-test shows average MITF expression in the Group K and Group P 27.833 vs 15.422 % MITF, and 16.828 vs 7.822 % pixel melanin for the melanin amount. The differences between two variables were meaningful as the p value <0.001. Conclusions: Conclusion for this experiment is that 30% Robusta coffee silverskin ethyl acetate fraction cream inhibited the increase of MITF expression and melanin amount in adult male guinea pigs exposed to UVB.