Intense UV Radiation Research Articles

High-altitude aquatic ecosystems offer faster aging rate of plastics

While research on the aging behavior of plastics in aquatic systems is extensive, studies focusing on high-altitude ecosystems, characterized by higher solar radiation and lower temperatures, remain limited. This study investigated the long-term aging behavior of non-biodegradable plastics (non-BPs), namely polyethylene terephthalate (PET) and polypropylene (PP) and biodegradable plastics (BPs), specifically polylactic acid plus polybutylene adipate-co-terephthalate (PLA + PBAT) and starch-based plastic (SBP), in a tributary of the Yarlung Zangbo River on the high-altitude Tibetan Plateau. Over 84 days of field aging, all four types of plastics exhibited initial rapid aging followed by deceleration. This aging process can be divided into two phases: rapid surface oxidation aging and an aging plateau phase. Notably, PP aged at a rate comparable to BPs, contrary to expectations of faster aging for BPs. Compared to low-altitude aquatic ecosystems, plastics in this study showed a faster aging rate. This was primarily due to intense ultraviolet radiation causing severe photoaging. Furthermore, the lower temperatures contributed to the formation of thinner biofilms. These thinner biofilms exhibited a reduced capacity to block light, further exacerbating the photoaging process of plastics. Statistical analysis results indicated that temperature, total nitrogen TN, and total phosphorus TP were likely the main water quality parameters influencing plastic aging. The varying effects of water properties and nutrients underscore the complex interaction of water quality parameters in high-altitude environments. Given the delicate nature of the high-altitude environment, the environmental impact of plastics, especially BPs, warrants careful consideration.

De Novo Genome Assembly of Toniniopsis dissimilis (Ramalinaceae, Lecanoromycetes) from Long Reads Shows a Comparatively High Composition of Biosynthetic Genes Putatively Involved in Melanin Synthesis.

Lichens have developed numerous adaptations to optimize their survival in various environmental conditions, largely by producing secondary compounds by the fungal partner. They often have antibiotic properties and are involved in protection against intensive UV radiation, pathogens, and herbivores. To contribute to the knowledge of the arsenal of secondary compounds in a crustose lichen species, we sequenced and assembled the genome of Toniniopsis dissimilis, an indicator of old-growth forests, using Oxford Nanopore Technologies (ONT, Oxford, UK) long reads. Our analyses focused on biosynthetic gene clusters (BGCs) and specifically on Type I Polyketide (T1PKS) genes involved in the biosynthesis of polyketides. We used the comparative genomic approach to compare the genome of T. dissimilis with six other members of the family Ramalinaceae and twenty additional lichen genomes from the database. With only six T1PKS genes, a comparatively low number of biosynthetic genes are present in the T. dissimilis genome; from those, two-thirds are putatively involved in melanin biosynthesis. The comparative analyses showed at least three potential pathways of melanin biosynthesis in T. dissimilis, namely via the formation of 1,3,6,8-tetrahydroxynaphthalene, naphthopyrone, or YWA1 putative precursors, which highlights its importance in T. dissimilis. In addition, we report the occurrence of genes encoding ribosomally synthesized and posttranslationally modified peptides (RiPPs) in lichens, with their highest number in T. dissimilis compared to other Ramalinaceae genomes. So far, no function has been assigned to RiPP-like proteins in lichens, which leaves potential for future research on this topic.

The extremotolerant desert moss Syntrichia caninervis is a promising pioneer plant for colonizing extraterrestrial environments

Many plans to establish human settlements on other planets focus on adapting crops to growth in controlled environments. However, these settlements will also require pioneer plants that can grow in the soils and harsh conditions found in extraterrestrial environments, such as those on Mars. Here, we report the extraordinary environmental resilience of Syntrichia caninervis, a desert moss that thrives in various extreme environments. S.caninervis has remarkable desiccation tolerance; even after losing >98% of its cellular water content, it can recover photosynthetic and physiological activities within seconds after rehydration. Intact plants can tolerate ultra-low temperatures and regenerate even after being stored in a freezer at -80°C for 5 years or in liquid nitrogen for 1month. S.caninervis also has super-resistance to gamma irradiation and can survive and maintain vitality in simulated Mars conditions; i.e., when simultaneously exposed to an anoxic atmosphere, extreme desiccation, low temperatures, and intense UV radiation. Our study shows that S.caninervis is among the most stress tolerant organisms. This work provides fundamental insights into the multi-stress tolerance of the desert moss S.caninervis, a promising candidate pioneer plant for colonizing extraterrestrial environments, laying the foundation for building biologically sustainable human habitats beyond Earth.

X-Ray Irradiation of the Giant Planet Orbiting the T Tauri Star TAP 26

We present new Chandra X-ray observations of TAP 26, a ≈17 Myr old magnetically active weak-lined T Tauri star that has been reported to host a massive planet in a ≈10.8 day orbit. At a separation of a = 0.097 au the planet will be exposed to intense X-ray and UV radiation from the star. The first observation caught the star in a state of elevated X-ray emission with variability on a timescale of a few hours and an X-ray temperature kT x ≈ 2–4 keV. Two subsequent observations 5–10 days later showed slow variability and a lower X-ray flux and temperature (kT x ≈ 1 keV). We characterize the X-ray emission and estimate the X-ray ionization and heating rates that will need to be incorporated into realistic models of the planet’s atmosphere.

Photodissociation and induced chemical asymmetries on ultra-hot gas giants

Context. Recent observations have resulted in the detection of chemical gradients on ultra-hot gas giants. Notwithstanding their high temperature, chemical reactions in ultra-hot atmospheres may occur in disequilibrium, due to vigorous day-night circulation and intense UV radiation from their stellar hosts. Aims. The goal of this work is to explore whether photochemistry is affecting the composition of ultra-hot giant planets, and if it can introduce horizontal chemical gradients. In particular, we focus on hydrogen cyanide (HCN) on WASP-76 b, as it is a photochemically active molecule with a reported detection on only one side of this planet. Methods. We used a pseudo-2D chemical kinetics code to model the chemical composition of WASP-76 b along its equator. Our approach improved on chemical equilibrium models by computing vertical mixing, horizontal advection, and photochemistry. Results. We find that the production of HCN is initiated through the thermal and photochemical dissociation of CO and N2 on the day side of WASP-76 b. The resulting radicals are subsequently transported to the night side via the equatorial jet stream, where they recombine into different molecules. This process results in an HCN gradient with a maximal abundance on the planet’s morning limb. We verified that photochemical dissociation is a necessary condition for this mechanism, as thermal dissociation alone proves insufficient. Other species produced via night-side disequilibrium chemistry are SO2 and S2. Conclusions. Our model acts as a proof of concept for chemical gradients on ultra-hot exoplanets. We demonstrate that even ultra-hot planets can exhibit disequilibrium chemistry and recommend that future studies do not neglect photochemistry in their analyses of ultra-hot planets.

Innovative design and field performance evaluation of a desert-adapted PV module for enhanced solar energy harvesting and reliability in harsh arid environments

The aim of this study is to present and evaluate the performance of a novel photovoltaic (PV) module configuration introduced as the “Desert Module,” developed to enhance the production and efficiency of PV power plants operating in harsh desert locations. This innovative module has been constructed by incorporating various technological solutions to address desert climate conditions such as high temperatures, soiling, and intense UV radiation. To assess the performance of the developed “Desert Module,” a comprehensive evaluation was conducted by comparing its performance to that of a conventional module. The study encompasses three main aspects: (i) indoor characterization, including flash and electroluminescence tests; (ii) performance assessment in a hot semi-arid climate over an eight-month period; and (iii) economic analysis to benchmark the costs of electricity produced from the proposed configuration against conventional alternatives. The results indicate that the Desert Module outperforms the conventional module across all performance metrics, enhancing the average efficiency by 0.5%. In addition, the performance ratio for the Desert Module stands at 0.87, surpassing the 0.82 achieved by the conventional module. Throughout the experiment, the average energy yield was enhanced by 5.8% and the conversion efficiency by 1.95%. Notably, during the hottest period (between July and August), the deviations on the energy yield and the conversion efficiency exceed 7% and 3%, respectively, in favor of the Desert Module, highlighting its resilience to the high temperatures characterizing desert locations. Furthermore, the Desert Module demonstrates a 4.44% reduction in the levelized cost of electricity compared to the conventional module, positioning it as a more economically viable option for large-scale energy generation in desert environments.

A Social Media-Delivered Melanoma Prevention Program for Young Women Engaged in Frequent UV Tanning: Protocol for a Randomized Controlled Trial.

Rates of melanoma have increased dramatically in the United States over the past 25 years, and it has become among the most prevalent cancers for young adult women. Intentional skin tanning leads to a pattern of intense and intermittent UV radiation exposure that is associated with increased risk of melanoma. Frequent tanning is most common among young women and is linked to a variety of sociocultural pressures that negatively impact body image and drive appearance control behaviors. Unfortunately, there are no established interventions designed for frequent tanners. This intervention addresses this gap with unique content informed by body image and acceptance-based interventions. The intervention is delivered using Facebook secret groups, an approach designed to support behavior change and ensure scalability. This study aims to describe the rationale and methodology of a randomized controlled trial of a melanoma prevention program targeting young women engaged in frequent indoor or outdoor UV tanning. Participants are women aged 18-25 years who report high-risk tanning (ie, at least 10 indoor tanning sessions in the past 12 months or 10 outdoor sessions in the previous summer). After recruitment and screening, participants completed a baseline survey and were randomly assigned to receive the intervention or an attention-matched control condition. Both conditions were 8-week-long Facebook groups (approximately 25 members each) with daily posting of content. Follow-up surveys are administered at 3, 8, and 18 months after baseline. The primary trial outcome is the combined number of indoor and outdoor tanning sessions reported at the 8-month follow-up. Hypothesized intervention mediators are assessed at the 3-month follow-up. This project was funded by a National Cancer Institute award (R01 CA218068), and the trial procedures were approved by the University of Kentucky Institutional Review Board in February 2020. Trial recruitment and enrollment occurred in 6 waves of data collection, which started in February 2022 and closed in May 2023. The study is closed to enrollment but remains open for follow-ups, and this protocol report was prepared before data analyses. As of February 2024, all participants have completed the 8-month follow-up assessment, and data collection is scheduled to close by the end of 2024 after the collection of the 18-month follow-up. This trial will contribute unique knowledge to the field of skin cancer prevention, as no fully powered trials have examined the efficacy of an intervention designed for frequent indoor or outdoor tanning. The trial may also contribute evidence of the value in translating principles of body image and acceptance-based interventions into the field of skin cancer prevention and beyond. If successful, the use of the Facebook platform is intended to aid in dissemination as it provides a way to embed the intervention into individuals' everyday routines. ClinicalTrials.gov NCT03441321; https://clinicaltrials.gov/study/NCT03441321. DERR1-10.2196/56562.

Novel Lignin-Functionalized Waterborne Epoxy Composite Coatings with Excellent Anti-Aging, UV Resistance, and Interfacial Anti-Corrosion Performance.

Developing high-performance lignin anti-corrosive waterborne epoxy (WEP) coatings is conducive to the advancement of environmentally friendly coatings and the value-added utilization of lignin. In this work, a functionalized biomass waterborne epoxy composite coating is prepared using quaternized sodium lignosulfonate (QLS) as a functional nanofiller for mild carbon steel protection. The results showed that QLS has excellent dispersion and interface compatibility within WEP, and its abundant phenolic hydroxyl, sulfonate, quaternary ammonium groups, and nanoparticle structure endowed the coating with excellent corrosion inhibition and superior barrier properties. The corrosion inhibition efficiency of 100mgL-1 QLS in carbon steel immersed in a 3.5wt% NaCl solution reached 95.76%. Furthermore, the coating maintained an impedance modulus of 2.29×106Ωcm2 (|Z|0.01Hz) after being immersed for 51 days in the high-salt system. In addition, QLS imparted UV-blocking properties and thermal-oxygen aging resistance to the coating, as evidenced by a |Z|0.01Hz of 1.04×107Ωcm2 after seven days of UV aging while still maintaining a similar magnitude as before aging. The green lignin/WEP functional coatings effectively withstand the challenging outdoor environment characterized by high salt concentration and intense UV radiation, thereby demonstrating promising prospects for application in metal protection.

Natural transformation-specific DprA coordinate DNA double-strand break repair pathways in heavily irradiated D. radiodurans.

Deinococcus radiodurans exhibits remarkable survival under extreme conditions, including ionizing radiation, desiccation, and various DNA-damaging agents. It employs unique repair mechanisms, such as single-strand annealing (SSA) and extended synthesis-dependent strand annealing (ESDSA), to efficiently restore damaged genome. In this study, we investigate the role of the natural transformation-specific protein DprA in DNA repair pathways following acute gamma radiation exposure. Our findings demonstrate that the absence of DprA leads to rapid repair of gamma radiation-induced DNA double-strand breaks primarily occur through SSA repair pathway. Additionally, our findings suggest that the DprA protein may hinder both the SSA and ESDSA repair pathways, albeit in distinct manners. Overall, our results highlight the crucial function of DprA in the selection between SSA and ESDSA pathways for DNA repair in heavily irradiated D. radiodurans.IMPORTANCEDeinococcus radiodurans exhibits an extraordinary ability to endure and thrive in extreme environments, including exposure to radiation, desiccation, and damaging chemicals, as well as intense UV radiation. The bacterium has evolved highly efficient repair mechanisms capable of rapidly mending hundreds of DNA fragments in its genome. Our research indicates that natural transformation (NT)-specific dprA genes play a pivotal role in regulating DNA repair in response to radiation. Remarkably, we found that DprA is instrumental in selecting DNA double-strand break repair pathways, a novel function that has not been reported before. This unique regulatory mechanism highlights the indispensable role of DprA beyond its native function in NT and underscores its ubiquitous presence across various bacterial species, regardless of their NT proficiency. These findings shed new light on the resilience and adaptability of Deinococcus radiodurans, opening avenues for further exploration into its exceptional survival strategies.

Microbial diversity in polyextreme salt flats and their potential applications.

Recent geological, hydrochemical, and mineralogical studies performed on hypersaline salt flats have given insights into similar geo-morphologic features on Mars. These salt-encrusted depressions are widely spread across the Earth, where they are characterized by high salt concentrations, intense UV radiation, high evaporation, and low precipitation. Their surfaces are completely dry in summer; intermittent flooding occurs in winter turning them into transitory hypersaline lakes. Thanks to new approaches such as culture-dependent, culture-independent, and metagenomic-based methods, it is important to study microbial life under polyextreme conditions and understand what lives in these dynamic ecosystems and how they function. Regarding these particular features, new halophilic microorganisms have been isolated from some salt flats and identified as excellent producers of primary and secondary metabolites and granules such as halocins, enzymes, carotenoids, polyhydroxyalkanoates, and exopolysaccharides. Additionally, halophilic microorganisms are implemented in heavy metal bioremediation and hypersaline wastewater treatment. As a result, there is a growing interest in the distribution of halophilic microorganisms around the world that can be looked upon as good models to develop sustainable biotechnological processes for all fields. This review provides insights into diversity, ecology, metabolism, and genomics of halophiles in hypersaline salt flats worldwide as well as their potential uses in biotechnology.

Photocatalytic degradation-based ambient mass spectrometry imaging for enhancing detection coverage of poorly-ionizable lipidomes

Localization of lipidomes and tracking their spatial changes in tissues by mass spectrometry imaging (MSI) plays an important role in unveiling the mechanisms of living processes, diseases and therapeutic treatments. However, it is always challenging to achieve direct MSI of poorly-ionizable lipids, such as glycolipids and glycerolipids, due to the strong ion suppression and isobaric peaks interference from high-abundance phosphatidylcholines (PCs) in tissues. Here we developed a photocatalytic degradation-based ambient liquid extraction MSI method to largely enhance the detection coverage of poorly-ionizable lipids by rapid online removal of PCs in MSI. Phospholipids were found to be selectively photodegraded on TiO2 surface in acidic conditions in the presence of water under UV irradiation, while other poorly-ionizable lipids remained. Sulfate ion could largely improve the degradation efficiencies. Anatase nanoparticles-embedded TiO2 monolith was in-situ synthesized in the capillary of ambient liquid extraction system, and rapid online photodegradation of PCs was achieved during MSI with efficiency >80 %, largely reducing ion suppression. The pathway analysis showed that PC was oxidatively degraded starting from hydroxylation of C=C bonds. With intense UV irradiation, PCs were completely degraded into small molecules<200 Da without interference on the detection of endogenous lipids. With the new MSI method, detection coverage to cerebrosides, ceramides and diglycerides was enhanced by 2–9 times comparing with traditional MSI. Clearer localizations were observed for poorly-ionizable lipids via the new method than traditional method. Thus, this work provided a complementary MSI method for traditional MSI to address the issues on direct imaging of poorly ionizable lipids in ambient conditions.

A UV-Resistant Heterogeneous Wettability Patterned Surface.

Preparing UV-resistant heterogeneous wettability patterns is critical for the practical application of surfaces with heterogeneous wettability. However, combining UV-resistant superhydrophobic and superhydrophilic materials on heterogeneous surfaces is challenging. Inspired by the structure of cell membranes, a UV-resistant heterogeneous wettability-patterned surface (UPS) is designed via laser ablation of the coating of multilayer structures. UV-resistant superhydrophobic silica patterns can be created in situ on surfaces covered with superhydrophilic TiO2 nanoparticles. The UV resistance time of the UPS with a TiO2 -based surface is more than two orders of magnitude higher than that obtained with other surface molecular modification methods that require a mask. The cell-membrane-like structure of the UPS regulates the migration of internal siloxane chain segments in the hydrophilic and hydrophobic regions of the surface. The UPS enables efficient patterning of functional materials under UV irradiation, controlling the wetting behavior of liquids in open-air systems. Furthermore, its heterogeneous wettability remains stable even after 50h of intense UV irradiation (365nm, 500mW cm-2 ). These UV-resistant heterogeneous wettability patterned surfaces will likely be applied in microfluidics, cell culture, energy conversion, and water collection in the future. This article is protected by copyright. All rights reserved.

Study on UV aging characteristics of low-grade asphalt in the desert climate

The Taklamakan Desert in China’s Xinjiang region faces severe heat conditions that cause rutting in asphalt pavements. In order to combat this issue, local construction management has been advocating for the utilization of low-grade asphalt with penetration levels between 20 and 50, to enhance the pavement’s resistance to rutting. However, there is limited research on the durability of low-grade asphalt under intense UV irradiation in the region. To this end, a multiscale investigation was conducted, examining three different types of asphalt (30#, 50#, and 70#), under various conditions such as virgin, UV aging, and Pressure Aging Vessel aging. Analytical techniques such as Atomic Force Microscope, Gel Permeation Chromatography, Fourier Transform Infrared Spectroscopy, Dynamic Shear Rheology, and Bending Beam Rheometer were employed. The results revealed that the surface roughness of the three types of asphalt increased by 15.50% (30#), 5.99% (50#), and 2.70% (70#) after UV aging, compared to the virgin samples. Furthermore, the adhesion properties of lower-grade asphalt were less affected by UV aging. Weight-average molecular weight of the three types of asphalt increased significantly after UV aging, with a 26.96% increase in 30#, 51.92% increase in 50#, and 43.76% increase in 70# compared to the samples prior to UV aging. The 30# asphalt with higher large molecule content exhibited slower UV aging. The 30# asphalt also exhibited the smallest increase of C=O and S=O after UV aging among the three types of asphalt. The study also found that UV aging had a lesser effect on the high- and low-temperature performance of asphalt, compared to PAV aging. Overall, the effects of UV irradiation on various properties of 30# asphalt were less pronounced than those of 50# and 70# asphalt. These findings offer valuable insights into aging resistance in the Taklamakan Desert, benefiting road contractors and the academic community.

Whole-genome sequencing reveals adaptations of hairy-footed jerboas (Dipus, Dipodidae) to diverse desert environments

BackgroundEnvironmental conditions vary among deserts across the world, spanning from hyper-arid to high-elevation deserts. However, prior genomic studies on desert adaptation have focused on desert and non-desert comparisons overlooking the complexity of conditions within deserts. Focusing on the adaptation mechanisms to diverse desert environments will advance our understanding of how species adapt to extreme desert environments. The hairy-footed jerboas are well adapted to diverse desert environments, inhabiting high-altitude arid regions, hyper-arid deserts, and semi-deserts, but the genetic basis of their adaptation to different deserts remains unknown.ResultsHere, we sequenced the whole genome of 83 hairy-footed jerboas from distinct desert zones in China to assess how they responded under contrasting conditions. Population genomics analyses reveal the existence of three species in hairy-footed jerboas distributed in China: Dipus deasyi, Dipus sagitta, and Dipus sowerbyi. Analyses of selection between high-altitude desert (elevation ≥ 3000m) and low-altitude desert (< 500m) populations identified two strongly selected genes, ATR and HIF1AN, associated with intense UV radiation and hypoxia in high-altitude environments. A number of candidate genes involved in energy and water homeostasis were detected in the comparative genomic analyses of hyper-arid desert (average annual precipitation < 70mm) and arid desert (< 200mm) populations versus semi-desert (> 360mm) populations. Hyper-arid desert animals also exhibited stronger adaptive selection in energy homeostasis, suggesting water and resource scarcity may be the main drivers of desert adaptation in hairy-footed jerboas.ConclusionsOur study challenges the view of deserts as homogeneous environments and shows that distinct genomic adaptations can be found among desert animals depending on their habitats.

New Insights on the Origin of Life: The Role of Silico-Carbonates of Ba (II) to Preserve DNA against Highly Intense UV Radiation.

Understanding the origin of life on our planet has generated diverse theories. Currently, the theory is that life has a single origin; however, its starting point has not been defined. As evidenced, it is indispensable to unify the different theories to reach a single theory that would also allow linking the different areas of knowledge to finally understand the mechanism by which life originated on Earth. In this regard, aiming at contributing to the unification of the diverse theories on the origin of life, in this work, the hypothesis based on the condition that silica-carbonates of alkaline earth metals, called biomorphs, are the ones that could unify all the proposed theories on the origin of life is proposed. Aimed at evaluating if this hypothesis is viable, this work assessed whether biomorphs are able to protect the DNA from continuous UV radiation under two conditions that emulate the habitats that could have co-existed in the Precambrian and, after the radiation, evaluated the time during which DNA remained inside the biomorphs. Our results showed that biomorphs can protect the DNA for months after continuous UV exposure. It was also determined that biomorphs protect the DNA from external factors in different habitats, like normal atmospheric conditions and in aqueous environments. The obtained data allowed me to infer that biomorphs may be the gap that unifies the diverse proposed theories on the origin of life in our Planet.

The genome of the glasshouse plant noble rhubarb (Rheum nobile) provides a window into alpine adaptation

Glasshouse plants are species that trap warmth via specialized morphology and physiology, mimicking a human glasshouse. In the Himalayan alpine region, the highly specialized glasshouse morphology has independently evolved in distinct lineages to adapt to intensive UV radiation and low temperature. Here we demonstrate that the glasshouse structure – specialized cauline leaves – is highly effective in absorbing UV light but transmitting visible and infrared light, creating an optimal microclimate for the development of reproductive organs. We reveal that this glasshouse syndrome has evolved at least three times independently in the rhubarb genus Rheum. We report the genome sequence of the flagship glasshouse plant Rheum nobile and identify key genetic network modules in association with the morphological transition to specialized glasshouse leaves, including active secondary cell wall biogenesis, upregulated cuticular cutin biosynthesis, and suppression of photosynthesis and terpenoid biosynthesis. The distinct cell wall organization and cuticle development might be important for the specialized optical property of glasshouse leaves. We also find that the expansion of LTRs has likely played an important role in noble rhubarb adaptation to high elevation environments. Our study will enable additional comparative analyses to identify the genetic basis underlying the convergent occurrence of glasshouse syndrome.

Highly-transparent fluorinated epoxy coating prepared via ring-opening of thiolactone and thiol-click reactions for robust omniphobicity

Transparent omniphobic coatings have attracted extensive research over the past decade to meet growing application demands. Polydimethylsiloxane (PDMS)-based anti-fouling coatings have been widely reported to contribute a liquid-like surface for liquid repellency. The bulky PDMS chains usually make the surface greasy and energy-consuming. Fluorinated epoxy is expected to overcome the above drawbacks and contribute to excellent mechanical robustness. However, the reported fluorinated epoxy coatings are unsatisfactory due to severe phase separation, excessive fluorine content, poor self-healing and weatherability. In this work, a thiolactone-terminated fluorinated prepolymer (TTFP) was prepared through thiol-click chemistry. The thiolactone structure limited the phase separation and reacted efficiently with epoxy resin in a thiol-click manner after ring-opening. The flexible TTFP molecules had a strong surface migration ability, allowing the product coating to be liquid repellent with a low fluorine content and self-healed after damage. Therefore, a low-cost, eco-friendly, anti-ultraviolet, self-healed, highly transparent, mechanically robust and chemically resistant fluorinated epoxy coating was proposed. In addition to the excellent repellency to ink traces, fingerprints and thick paint, the coating with 5H pencil hardness could maintain omniphobic properties after 100 h of intensive UV irradiation or 12 h of alkali corrosion. Benefiting from the strong surface migration ability of flexible fluoroalkyl chains, the coating could recover its omniphobicity within 30 min of heating. The characterization results show the excellent comprehensive properties of the coating and its great potential for application in various scenarios.

Mapping NGC 7027 in New Light: CO+ and HCO+ Emission Reveal Its Photon- and X-Ray-dominated Regions

The young and well-studied planetary nebula (PN) NGC 7027 harbors significant molecular gas that is irradiated by luminous, pointlike UV (central star) and diffuse (shocked nebular) X-ray emission. This nebula represents an excellent subject to investigate the molecular chemistry and physical conditions within photon- and X-ray-dominated regions (PDRs and XDRs). As yet, the exact formation routes of CO+ and HCO+ in PN environments remain uncertain. Here we present ∼2″ resolution maps of NGC 7027 in the irradiation tracers CO+ and HCO+ obtained with the IRAM NOEMA interferometer, along with SMA CO and HST 2.12 μm H2 data for context. The CO+ map constitutes the first interferometric map of this molecular ion in any PN. Comparison of CO+ and HCO+ maps reveals strikingly different emission morphologies, as well as a systematic spatial displacement between the two molecules; the regions of brightest HCO+, found along the central waist of the nebula, are radially offset by ∼1″ (∼900 au) outside the corresponding CO+ emission peaks. The CO+ emission furthermore precisely traces the inner boundaries of the nebula’s PDR (as delineated by near-IR H2 emission), suggesting that central star UV emission drives CO+ formation. The displacement of HCO+ radially outward with respect to CO+ is indicative that dust-penetrating soft X-rays are responsible for enhancing the HCO+ abundance in the surrounding molecular envelope, forming an XDR. These interferometric CO+ and HCO+ observations of NGC 7027 thus clearly establish the spatial distinction between the PDR and XDR formed (respectively) by intense UV and X-ray irradiation of molecular gas.

X-ray and UV radiation in the planet-forming T-Tauri system PDS 70. Signs of accretion and coronal activity

ABSTRACT Planet formation takes place in protoplanetary discs around young T-Tauri stars. PDS 70 is one of the first confirmed examples of a system where the planets are currently forming in gaps in the disc, and can be directly imaged. One of the main early influences on planet formation is the lifetime of the protoplanetary disc, which is limited by the intense stellar X-ray and UV radiation. Stellar coronal activity and accretion of material onto the star are both potential sources of XUV radiation. Previous Swift observations detected UV emission, which were consistent with a low rate of accretion. We present follow up observations with the XMM-Newton observatory, which observed PDS 70 simultaneously in X-ray and UV in order to determine intensity of XUV radiation in the system, and identify if the source is coronal, accretion, or both. We detect a strong source in both X-ray and UV, with an average X-ray 0.2–12 keV luminosity of 1.37 × 1030 erg s−1, and a possible flare which increased the luminosity to 2.8 × 1030 erg s−1. The UV flux density is in excess of what would be expected from chromospheric emission, and supports the interpretation that PDS 70 has continuing weak accretion less than ∼10−10 M⊙ yr−1. The implications of the detected X-ray and UV radiation are that the disc is likely to be in the final stages of dispersal, and will be completely evaporated in the next million years, bringing an end to the primary planet formation process.

In situ performance and stability tests of large-area flexible polymer solar cells in the 35-km stratospheric environment.

Flexible organic solar cells (FOSCs) are one of the most promising power sources for aerospace aircraft due to their attractive advantages with high power-per-weight ratio and excellent mechanical flexibility. Understanding the performance and stability of high-performance FOSCs is essential for the further development of FOSCs for aerospace applications. In this paper, after systematic investigations on the performance of the state-of-the-art high-performance solar cells under thermal cycle and intensive UV irradiation conditions, in situ performance and stability tests of the solar cells in the 35km stratospheric environment were carried out through a high-altitude balloon uploading. The encapsulated FOSCs with an area of 0.64cm2 gave the highest power density of 15.26mW/cm2 and an efficiency over 11%, corresponding to a power-per-weight ratio of over 3.32kW/kg. More importantly, the cells showed stable power output during the 3-h continuous flight at 35km and only 10% performance decay after return to the lab, suggesting promising stability of the FOSCs in the stratospheric environment.