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The interactions of electrons with molecular systems under various conditions are essential to interdisciplinary research fields extending over the fundamental and applied sciences. In particular, investigating electron-induced ionization and dissociation of molecules may shed light on the radiation damage to living cells, the physicochemical processes in interstellar environments, and reaction mechanisms occurring in combustion or plasma. We have, therefore, studied electron-induced ionization and dissociation of the gas phase 3,4-dihydro-2H-pyran (DHP), a cyclic ether appearing to be a viable moiety for developing efficient clinical pharmacokinetics and revealing the mechanisms of biofuel combustion. The mass spectra in the m/z = 10–90 mass range were measured at several different energies of the ionizing electron beam using mass spectrometry. The mass spectra of DHP at the same energies were simulated using on-the-fly semi-classical molecular dynamics (MD) within the framework of the QCxMS formalism. The MD settings were suitably adjusted until a good agreement with the experimental mass spectra intensities was achieved, thus enabling a reliable assignment of cations and unraveling the plausible fragmentation channels. Based on the measurement of the absolute total ionization cross section of DHP (18.1 ± 0.9) × 10−16 cm2 at 100 eV energy, the absolute total and partial ionization cross sections of DHP were determined in the 5–140 eV electron energy. Moreover, a machine learning algorithm that was trained with measured cross sections from 25 different molecules was used to predict the total ionization cross section for DHP. Comparison of the machine learning simulation with the measured data showed acceptable agreement, similar to that achieved in past predictions of the algorithm. [ABSTRACT FROM AUTHOR]

The outstanding radiation damage stability of an NiCoCrFePd high entropy alloy (HEA) as compared to conventional alloys poses the question for the mechanism of an ion–matter interaction. The positron annihilation lifetime spectroscopic and TEM (transmission electron microscopic) measurements are implemented to trace different kinds of defects produced by 120 MeV Au+9 ion irradiation and their evolution as a function of ion fluence. The variation of lifetimes and corresponding intensities with the ion fluence indicates the formation of dislocation-type defects at a lower ion fluence and vacancy clusters at a higher ion fluence caused by coalescence or agglomeration of dislocation defects. Formation of different types of defects in turn modulates the strain development inside the crystal. Additionally, the HR-TEM investigation of NiCoCrFePd HEA also exhibits the formation of dislocation and vacancy clusters with the average size of vacancy clusters increases from ∼2.9 ± 0.1 to ∼3.8 ± 0.1 nm with the increases in the ion fluence. Surprisingly, the average defect cluster size in NiCoCrFePd HEA is suppressed compared to NiCoCrFe MEA, thereby showing the enhanced radiation stability on Pd incorporation due to the high defect recombination caused by reduced thermal conductivity and high lattice distortion. Nano-indentation measurement shows that the radiation hardening behavior of the NiCoCrFePd HEA responded slowly owing to its damage suppression property as compared to the NiCoCrFe MEA. Additionally, softening behavior also appeared at an early fluence in NiCoCrFe MEA compared to the NiCoCrFePd HEA signifying its excellent resistance to defect accumulation. [ABSTRACT FROM AUTHOR]

Extensive experimental and computational studies have demonstrated outstanding physical and chemical properties of the novel materials of compositionally complex carbides (CCCs), enabling their promising applications in advanced fission and fusion energy systems. This perspective provides a comprehensive overview of radiation damage behavior reported in the literature to understand the fundamental mechanisms related to the impact of multi-principal metal components on phase stability, irradiation-induced defect clusters, irradiation hardening, and thermal conductivity of compositionally complex carbides. Several future research directions are recommended to critically evaluate the feasibility of designing and developing new ceramic materials for extreme environments using the transformative "multi-principal component" concept. Compared to the existing materials for nuclear applications including stainless steels, nickel alloys, ZrC, SiC, and potentially high-entropy alloys, as well as certain other compositionally complex ceramic families. CCCs appear to be more resistant to amorphization, growth of irradiation defect clusters, and void swelling. [ABSTRACT FROM AUTHOR]

This paper reviews the evolution of the charge pumping (CP) technique and its applications from the micrometer-scale to the atomic-scale device era. We describe the more significant milestones of the CP technique (CPT) over the past couple of decades, giving insight into its potentialities. We start with the most popular one "traditional or conventional CP" and follow up with its different extensions in various fields like transistor reliability and radiation damage characterizations in devices fabricated with old and new semiconductor and dielectric materials. We show its easy adaptability for transistors with specific geometries. Advantages, weaknesses, as well as future tendencies of CPT and its variants, are also discussed. [ABSTRACT FROM AUTHOR]

Background: Radiation therapy has become an important treatment for many malignant tumours after surgery and for palliative tumour care. Although modern radiotherapy technology is constantly improving, radiation damage to normal tissues is often difficult to avoid, and radiation-induced skin injury (RSI) is a common complication, manifested as skin erythema, peeling, ulceration, and even bone and deep organ damage, seriously affect the quality of life for patients. Basic research and clinical trials related to RSI have achieved certain results, while no researchers have conducted comprehensive bibliometric studies. Objective: A comprehensive bibliometric analysis of publications on RSI published between 2004 and 2023 was conducted to identify current hotspots and future directions in this area of study. Methods: RSI-related publications published between January 1, 2004, and December 31, 2023, were retrieved from the Web of Science Core Collection (WoSCC) database for analysis using VOSviewer and CiteSpace analytics. Results: A total of 1009 publications on RSI from 2004 to 2023 were included in the WoSCC database. The United States had the highest productivity with 299 papers, accounting for 29.63% of the total production, followed by China with 193 papers (19.13%) and Japan with 111 papers (11.00%). In terms of research institutions and journals, the University of Toronto and Journal of Supportive Care in Cancer published the highest number of papers. Professor Edward Chow published the most articles, while Professor Shuyu Zhang was the most cited. The top ten most-cited papers focused on the pathogenesis, prevention, and management of RSI. Keyword co-occurrence analysis and the top 25 keywords with the strongest citation bursts suggest that current research focuses on the pathogenesis, prevention, and treatment management of RSI. Conclusion: This study conducted a systematic bibliometric analysis of RSI publications from 2004 to 2023; identified the trends in RSI publications, major research countries, major research institutions, major research journals, major research authors, and major research keywords; and revealed the future development direction and research hotspots of this field. This study provides a valuable reference for future RSI research. [ABSTRACT FROM AUTHOR]

An accurate description of short-range interactions among atoms is crucial for simulating irradiation effects in applications related to ion modification techniques. A smooth integration of the Ziegler–Biersack–Littmark (ZBL) potential with the adaptive intermolecular reactive empirical bond-order (AIREBO) potential was achieved to accurately describe the short-range interactions for carbon-based materials. The influence of the ZBL connection on potential energy, force, and various AIREBO components, including reactive empirical bond-order (REBO), Lennard–Jones (LJ), and the torsional component, was examined with configurations of the dimer structure, tetrahedron structure, and monolayer graphene. The REBO component is primarily responsible for the repulsive force, while the LJ component is mainly active in long-range interactions. It is shown that under certain conditions, the torsional energy can lead to a strong repulsive force at short range. Molecular dynamics simulations were performed to study the collision process in configurations of the C-C dimer and bulk graphite. Cascade collisions in graphite with kinetic energies of 1 keV and 10 keV for primary knock-on atoms showed that the short-range description can greatly impact the number of generated defects and their morphology. [ABSTRACT FROM AUTHOR]

Accessory minerals like zircon, rutile and monazite are routinely studied to inform about the timing and nature of geological processes. These studies are underpinned by our understanding of the transfer processes of trace elements and the assumption that the isotopic systems remain undisturbed. However, the presence of microstructures or Pb-bearing phases in minerals can lead to the alteration of the Pb isotopic composition. To gain insight into the relationship between Pb isotopic alterations from inclusions and microstructures, this study focused on inclusions from an ultra-high-temperature metamorphic rutile. The studied inclusions are submicrometer monazites, a common mineral rich in Pb but normally not present in rutile. The sample is sourced from Mt. Hardy, Napier Complex, East Antarctica, an ultra-high-temperature (UHT) metamorphic terrane. By applying correlative analytical techniques, including electron backscatter diffraction mapping, transmission electron microscopy (TEM), and atom probe tomography, it is shown that monazite inclusions are often in contact with low-angle boundaries and yield no preferred orientation. TEM analysis shows the monazite core has a mottled texture due to the presence of radiation damage and nanoclusters associated with the radiation damage defects that are rich in U, Pb, and Ca. Some monazites exhibit a core-rim structure. The rim yields clusters composed of Ca- and Li-phosphate that enclose Pb nanoclusters that are only present in small amounts compared to the core, with Pb likely diffused into the rutile-monazite interface. These textures are the result of two stages of Pb mobility. Initial Pb segregation was driven by volume diffusion during UHT metamorphism (2500 Ma). The second stage is a stress-induced recrystallization during exhumation, leading to recrystallization of the monazite rim and trace element transport. The isotopic signature of Pb trapped within the rutile-monazite interface constrains the timing of Pb mobility to ca. 550 Ma. [ABSTRACT FROM AUTHOR]

Large number of sensitizers and protectors of cells, tissues, organs and organisms are being discussed in this review. Attention is paid to metals, nanoparticles or organic compounds as modifiers. They can modify the radiation sensitivity by 20–60%. In most cases, sensitization is caused by an increase in DNA damage or a decrease in the repair of radiation damage. The protection can be caused in many cases by repair of damaged DNA molecules, proteins or enzymes, or by reducing the ROS concentration. The most current research tasks in this area are formulated. A new quantitative and reproducible method of evaluating modifiers is discussed. [ABSTRACT FROM AUTHOR]

The resonant photoelectron spectroscopy (ResPes) of new and aged δ-Pu(Ga) is reassessed by using the small oxygen contaminant peaks as an independent and quantitative check upon conventional cross-photon-energy normalization. Good agreement is found between the measured oxygen intensities and the atomic cross section calculations. Consistent with earlier analyses, the radiation induced damage in the aged samples is found to compress and sharpen the 5f peaks. This is associated with increased localization of the 5f bands, corresponding to the 5f density of states calculations that show a narrowing of 5f bandwidth with cluster size diminishment. [ABSTRACT FROM AUTHOR]

Aerosol science is of utmost importance for both climate and public health research, and in recent years X‐ray techniques have proven effective tools for aerosol‐particle characterization. To date, such methods have often involved the study of particles collected onto a substrate, but a high photon flux may cause radiation damage to such deposited particles and volatile components can potentially react with the surrounding environment after sampling. These and many other factors make studies on collected aerosol particles challenging. Therefore, a new aerosol sample‐delivery system dedicated to X‐ray photoelectron spectroscopy studies of aerosol particles and gas molecules in‐flight has been developed at the MAX IV Laboratory. The aerosol particles are brought from atmospheric pressure to vacuum in a continuous flow, ensuring that the sample is constantly renewed, thus avoiding radiation damage, and allowing measurements on the true unsupported aerosol. At the same time, available gas molecules can be used for energy calibration and to study gas‐particle partitioning. The design features of the aerosol sample‐delivery system and important information on the operation procedures are described in detail here. Furthermore, to demonstrate the experimental range of the aerosol sample‐delivery system, results from aerosol particles of different shape, size and composition are presented, including inorganic atmospheric aerosols, secondary organic aerosols and engineered nanoparticles. [ABSTRACT FROM AUTHOR]

Acute, high-dose radiation exposure results in life-threatening acute radiation syndrome (ARS) and debilitating delayed effects of acute radiation exposure (DEARE). The DEARE are a set of chronic multi-organ illnesses that can result in early death due to malignancy and other diseases. Animal models have proven essential in understanding the natural history of ARS and DEARE and licensure of medical countermeasures (MCM) according to the FDA Animal Rule. Our lab has developed models of hematopoietic (H)-ARS and DEARE in inbred C57BL/6J and Jackson Diversity Outbred (JDO) mice of both sexes and various ages and have used these models to identify mechanisms of radiation damage and effective MCMs. Herein, aggregate data from studies conducted over decades in our lab, consisting of 3,250 total-body lethally irradiated C57BL/6J young adult mice and 1,188 H-ARS survivors from these studies, along with smaller datasets in C57BL/6J pediatric and geriatric mice and JDO mice, were examined for lifespan and development of thymic lymphoma in survivors up to 3 years of age. Lifespan was found to be significantly shortened in H-ARS survivors compared to age-matched nonirradiated controls in all four models. Males and females exhibited similar lifespans except in the young adult C57BL/ 6J model where males survived longer than females after 16 months of age. The incidence of thymic lymphoma was increased in H-ARS survivors from the young adult and pediatric C57BL/ 6J models. Consistent with our findings in H-ARS, geriatric mice appeared more radioresistant than other models, with a lifespan and thymic lymphoma incidence more similar to nonirradiated controls than other models. Increased levels of multiple pro-inflammatory cytokines in DEARE bone marrow and serum correlated with shortened lifespan and malignancy, consistent with other animal models and human data. Of interest, G-CSF levels in bone marrow and serum 8-11 months after irradiation were significantly increased in females. Importantly, treatment with granulopoietic cytokine MCM for radiomitigation of H-ARS did not influence the long-term survival rate or incidence of thymic lymphoma in any model. Taken together, these findings indicate that the lifespan of H-ARS survivors was significantly decreased regardless of age at time of exposure or genetic diversity, and was unaffected by earlier treatment with granulopoietic cytokines for radiomitigation of H-ARS. [ABSTRACT FROM AUTHOR]

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4-Nitrobenzaldehyde (C7H5NO3) (4NB) single crystals were obtained by slow evaporation technique. Single crystals were made paramagnetic by irradiation with a 60Co-gamma rays. Electron Paramagnetic Resonance (EPR) Spectroscopy method was used to detect the radiation damage center formed in the single crystals. As a result of temperature scanning of EPR spectra at different temperatures between 120 and 470 K, it was found to be independent of temperature. That's why the EPR study was done only at 300 K. The radiation effect caused the formation of the 4NB anion radical in the 4NB single crystal. All the protons in the structure created hyperfine structure splittings. The principal values of the hyperfine structure constants resulting from the interaction of the unpaired electron with protons, the principal values of the g-tensor and their direction cosines were calculated. [ABSTRACT FROM AUTHOR]

Perovskite solar cells are emerging as one of the most promising energy sources for space applications. However, the displacement damage of solar cells in the space environment has gradually deteriorated their performance. In this work, the depth distribution of primary knocked-on atoms (PKA), non-ionizing energy loss and defect concentration of CsPbI3-based perovskite solar cells irradiated by 0.1–2000 MeV protons have been simulated by the Geant4 toolkit. It is found that the PKA yield shows an obvious step behavior near the layer boundary of the solar cell, and that the electron and hole transport layers have the high defect concentration whereas the CsPbI3-based perovskite layer owns the least PKA yield. In particular, in the geostationary orbit, the radiation damage effect caused by space protons to the solar cells is approximately equivalent to that irradiated by 0.18 MeV protons, which provides a good reference for ground irradiation experiments for CsPbI3-based perovskite solar cells. [ABSTRACT FROM AUTHOR]

Nuclear power plants are aging around the world, and a precise assessment of irradiation damage in their components is needed. One key component, concrete, and specifically the silicates in its aggregates, can undergo significant expansion upon neutron radiation, which can lead to cracking and, ultimately, structural failure. However, assessing and predicting the extent of damage via neutron radiation is challenging due to reasons such as residual radioactivity and, most importantly, the high time involved. Here, we evaluate whether ion radiation can be a viable surrogate. Specifically, by employing Si2+ ion radiations and a comprehensive multi-modal imaging protocol, we report mineral-specific responses for key silicates such as quartz, albite, anorthite, and microcline. We find that 10 MeV Si2+ ions result in mineral expansions that are remarkably comparable to neutron radiation equivalent expansions (R2 = 0.86, RMSE = 1.29%), opening up pathways towards rapid assessment of silicates subject to irradiation. [ABSTRACT FROM AUTHOR]

Background: Xerostomia is a pathological condition characterized by decreased salivation due to salivary gland dysfunction and is frequently attributed to irreversible damage as a side effect of radiation therapy. Stem cell–derived organoid therapy has garnered attention as a promising avenue for resolving this issue. However, Matrigel, a hydrogel commonly used in organoid culture, is considered inappropriate for clinical use due to its undefined composition and immunogenicity. In this study, we aimed to develop a method for culturing collagen-based human salivary gland organoids (hSGOs) suitable for clinical applications and evaluated their therapeutic effectiveness. Methods: Human salivary gland stem cells were isolated from the salivary gland tissues and cultured in both Matrigel and collagen. We compared the gene and protein expression patterns of salivary gland–specific markers and measured amylase activity in the two types of hSGOs. To evaluate the therapeutic effects, we performed xenogeneic and allogeneic transplantation using human and mouse salivary gland organoids (hSGOs and mSGOs), respectively, in a mouse model of radiation-induced xerostomia. Results: hSGOs cultured in Matrigel exhibited self-renewal capacity and differentiated into acinar and ductal cell lineages. In collagen, they maintained a comparable self-renewal ability and more closely replicated the characteristics of salivary gland tissue following differentiation. Upon xenotransplantation of collagen-based hSGOs, we observed engraftment, which was verified by detecting human-specific nucleoli and E-cadherin expression. The expression of mucins, especially MUC5B, within the transplanted hSGOs suggested a potential improvement in the salivary composition. Moreover, the allograft procedure using mSGOs led to increased salivation, validating the efficacy of our approach. Conclusions: This study showed that collagen-based hSGOs can be used appropriately in clinical settings and demonstrated the effectiveness of an allograft procedure. Our research has laid the groundwork for the future application of collagen-based hSGOs in allogeneic clinical trials. [ABSTRACT FROM AUTHOR]

In major radiological events, rapid assays to detect ionizing radiation exposure are crucial for effective medical interventions. The purpose of these assays is twofold: to categorize affected individuals into groups for initial treatments, and to provide definitive dose estimates for continued care and epidemiology. However, existing high-throughput cytogenetic biodosimetry assays take about 3 days to yield results, which delays critical interventions. We have developed a multiwell-based variant of the chemical-induced G0-phase Premature Chromosome Condensation Assay that delivers same-day results. Our findings revealed that using a concentration of phosphatase inhibitor lower than recommended significantly increases the yield of cells with highly condensed chromosomes. These chromosomes exhibited increased fragmentation in a dose-dependent manner, enabling to quantify radiation damage using a custom Deep Learning algorithm. This algorithm demonstrated reasonable performance in categorizing doses into distinct treatment groups (84% and 80% accuracy for three and four iso-treatment dose bins, respectively) and showed reliability in determining the actual doses received (correlation coefficient of 0.879). This method is amendable to full automation and has the potential to address the need for same-day, high-throughput cytogenetic test for both dose categorization and dose reconstruction in large-scale radiation emergencies. [ABSTRACT FROM AUTHOR]

The Two-Photon Absorption–Transient Current Technique (TPA-TCT) is a device characterisation technique that enables three-dimensional spatial resolution. Laser light in the quadratic absorption regime is employed to generate excess charge carriers only in a small volume around the focal spot. The drift of the excess charge carriers is studied to obtain information about the device under test. Neutron-, proton-, and gamma-irradiated p-type pad silicon detectors up to equivalent fluences of about 7 × 1015  n eq / c m 2 and a dose of 186   M r a d are investigated to study irradiation-induced effects on the TPA-TCT. Neutron and proton irradiation lead to additional linear absorption, which does not occur in gamma-irradiated detectors. The additional absorption is related to cluster damage, and the absorption scales according to the non-ionising energy loss. The influence of irradiation on the two-photon absorption coefficient is investigated, as well as potential laser beam depletion by the irradiation-induced linear absorption. Further, the electric field in neutron- and proton-irradiated pad detectors at an equivalent fluence of about 7 × 1015  n eq / c m 2 is investigated, where the space charge of the proton-irradiated devices appears inverted compared to the neutron-irradiated device. [ABSTRACT FROM AUTHOR]

Exposure to ionizing radiation can induce genetic aberrations via unrepaired DNA strand breaks. To investigate quantitatively the dose–effect relationship at the molecular level, we irradiated dry pBR322 plasmid DNA with 3 MeV protons and assessed fragmentation yields at different radiation doses using long-read sequencing from Oxford Nanopore Technologies. This technology applied to a reference DNA model revealed dose-dependent fragmentation, as evidenced by read length distributions, showing no discernible radiation sensitivity in specific genetic sequences. In addition, we propose a method for directly measuring the single-strand break (SSB) yield. Furthermore, through a comparative study with a collection of previous works on dry DNA irradiation, we show that the irradiation protocol leads to biases in the definition of ionizing sources. We support this scenario by discussing the size distributions of nanopore sequencing reads in the light of Geant4 and Geant4-DNA simulation toolkit predictions. We show that integrating long-read sequencing technologies with advanced Monte Carlo simulations paves a promising path toward advancing our comprehension and prediction of radiation-induced DNA fragmentation. [ABSTRACT FROM AUTHOR]

Earth's biodiversity is increasingly threatened and at risk. We propose a passive lunar biorepository for long-term storage of prioritized taxa of live cryopreserved samples to safeguard Earth's biodiversity and to support future space exploration and planet terraforming. Our initial focus will be on cryopreserving animal skin samples with fibroblast cells. An exemplar system has been developed using cryopreserved fish fins from the Starry Goby, Asterropteryx semipunctata. Samples will be expanded into fibroblast cells, recryopreserved, and then tested in an Earth-based laboratory for robust packaging and sensitivity to radiation. Two key factors for this biorepository are the needs to reduce damage from radiation and to maintain the samples near –196° Celsius. Certain lunar sites near the poles may meet these criteria. If possible, further testing would occur on the International Space Station prior to storage on the Moon. To secure a positive shared future, this is an open call to participate in this decades-long program. [ABSTRACT FROM AUTHOR]

Cryo‐electron microscopy (cryo‐EM) has transformed structural biology over the past 12 years, with it now being routine rather than exceptional to reach a near‐atomic level of resolution for proteins and macromolecular complexes. Samples are immobilized by vitrification and this sample can be maintained at liquid nitrogen temperatures in the vacuum of the electron microscope with negligible sublimation. Due to the low electron doses needed to avoid radiation damage, averaging over tens of thousands to hundreds of thousands of particle images is used to achieve a high signal‐to‐noise ratio. An alternative approach has been proposed where samples are at room temperature in the liquid state, maintained in the vacuum of the electron microscope by thin film enclosures that are relatively transparent to electrons while preventing evaporation of the liquid. A paper has argued that using this liquid‐phase approach, higher resolution (3.2 Å) can be achieved than using cryo‐EM (3.4 Å) when imaging and reconstructing adeno‐associated virus particles. I show here that these assertions are untrue, and that basic principles in mathematics and physics would need to be violated to achieve the stated resolution in the liquid state. Thus, high resolution liquid phase EM of macromolecules remains science fiction. [ABSTRACT FROM AUTHOR]

Interstitial diffusion is important for radiation defect evolution in zirconium alloys. This study employed molecular dynamics simulations to investigate interstitial diffusion in α-Zr and its alloys with 1.0 at.% Nb and 1.0 at.% Sn using a variety of interatomic potentials. Pronounced differences in diffusion anisotropy were observed in pure Zr among the employed potentials. This was attributed to the considerable differences in migration barriers among the various interstitial configurations. The introduction of small concentrations of Nb and Sn solute atoms was found to significantly influence diffusion anisotropy by either directly participating in the diffusion process or altering the chemical environment around the diffusing species. Based on the moderate agreement of interstitial energetics in pure Zr, accurately describing interstitial diffusion in Zr alloys is expected to be more complex. This work underscores the importance of the careful validation and selection of interatomic potentials and highlights the need to understand the effects of solute atoms on interstitial diffusion. [ABSTRACT FROM AUTHOR]

Silicon Photomultipliers (SiPMs) are single photon detectors that gained increasing interest in many applications as an alternative to photomultiplier tubes. In the field of space experiments, where volume, weight and power consumption are a major constraint, their advantages like compactness, ruggedness, and their potential to achieve high quantum efficiency from UV to NIR makes them ideal candidates for spaceborne, low photon flux detectors. During space missions however, SiPMs are usually exposed to high levels of radiation, both ionizing and non-ionizing, which can deteriorate the performance of these detectors over time. The goal of this work is to compare process and layout variation of SiPMs in terms of their radiation damage effects to identify the features that helps reduce the deterioration of the performance and develop the next generation of more radiation-tolerant detectors. To do this, we used protons and X-rays to irradiate several Near Ultraviolet High-Density (NUV-HD) SiPMs with small areas (single microcell, 0.2 × 0.2 mm2 and 1 × 1 mm2) produced at Fondazione Bruno Kessler (FBK), Italy. We performed online current-voltage measurements right after each irradiation step, and a complete functional characterization before and after irradiation. We observed that the main contribution to performance degradation in space applications comes from proton damage in the form of an increase in primary dark count rate (DCR) proportional to the proton fluence and a reduction in activation energy. In this context, small active area devices show a lower DCR before and after irradiation, and we propose light or charge-focusing mechanisms as future developments for high-sensitivity radiation-tolerant detectors. [ABSTRACT FROM AUTHOR]

Radiation proctopathy (RP) is a common complication of radiotherapy for pelvic malignancies with high incidence. RP accompanies by microbial dysbiosis. However, how the gut microbiota affects the disease remains unclear. Here, metabolomics reveals that the fecal and serous concentrations of microbiota‐derived 3‐hydroxybutyrate (3HB) are significantly reduced in RP mice and radiotherapeutic patients. Moreover, the concentration of 3HB is negatively associated with the expression of proinflammatory IL6 that is increased along with the severity of radiation damage. 3HB treatment significantly downregulates IL6 expression and alleviates IL6‐mediated radiation damage. Irradiated cell‐fecal microbiota co‐culture experiments and in vivo assays show that such a radioprotection of 3HB is mediated by GPR43. Microbiome analysis reveals that radiation leads to a distinct bacterial community compared to untreated controls, in which Akkermansia muciniphila is significantly reduced in RP mice and radiotherapeutic patients and is associated with lower 3HB concentration. Gavage of A. muciniphila significantly increases 3HB concentration, downregulates GPR43 and IL6 expression, and ameliorates radiation damage. Collectively, these results demonstrate that the gut microbiota, including A. muciniphila, induce higher concentrations of 3HB to block GPR43‐mediated IL6 signaling, thereby conferring radioprotection. The findings reveal a novel implication of the gut‐immune axis in radiation pathophysiology, with potential therapeutic applications. [ABSTRACT FROM AUTHOR]

Single-event burnout and single-event leakage current (SELC) in silicon carbide (SiC) power devices induced by heavy ions severely limit their space application, and the underlying mechanism is still unclear. One fundamental problem is lack of high-resolution characterization of radiation damage in the irradiated SiC power devices, which is a crucial indicator of the related mechanism. In this Letter, high-resolution transmission electron microscopy (TEM) was used to characterize the radiation damage in the 1437.6 MeV 181Ta-irradiated SiC junction barrier Schottky diode under 200 V. The amorphous radiation damage with about 52 nm in diameter and 121 nm in length at the Schottky metal (Ti)–semiconductor (SiC) interface was observed. More importantly, in the damage site the atomic mixing of Ti, Si, and C was identified by electron energy loss spectroscopy and high-angle annular dark-field scanning TEM. It indicates that the melting of the Ti–SiC interface induced by localized Joule's heating is responsible for the amorphization and the possible formation of titanium silicide, titanium carbide, or ternary phases. The mushroom-like hillock in the Ti layer can be attributed to Rayleigh–Taylor instability, as another evidence for ever-happened localized melting near the Schottky interface. These modifications at nanoscale in turn cause localized degradation of the Schottky contact, resulting in permanent increase in leakage current. This experimental study provides very valuable clues for a thorough understanding of the SELC mechanism in SiC diodes. [ABSTRACT FROM AUTHOR]

Objective: A favorable effect of ultra-high dose rate (FLASH) radiation on normal tissue-sparing has been indicated in several preclinical studies. In these studies, the adverse effects of radiation damage were reduced without compromising tumor control. Most studies of proton FLASH investigate these effects within the entrance of a proton beam. However, the real advantage of proton therapy lies in the Spread-out Bragg Peak (SOBP), which allows for giving a high dose to a target with a limited dose to healthy tissue at the entrance of the beam. Therefore, a clinically relevant investigation of the FLASH effect would be of healthy tissues within a SOBP. Our study quantified the tissue-sparing effect of FLASH radiation on acute and late toxicity within an SOBP in a murine model. Material/Methods: Radiation-induced damage was assessed for acute and late toxicity in the same mice following irradiation with FLASH (Field dose rate of 60 Gy/s) or conventional (CONV, 0.34 Gy/s) dose rates. The right hindleg of unanesthetized female CDF1 mice was irradiated with single-fraction doses between 19.9-49.7 Gy for CONV and 30.4-65.9 Gy for FLASH with 5-8 mice per dose. The leg was placed in the middle of a 5 cm SOBP generated from a mono-energetic beam using a 2D range modulator. Acute skin toxicity quantified by hair loss, moist desquamation and toe separation was monitored daily within 29 days post-treatment. Late toxicity of fibrotic development measured by leg extendibility was monitored biweekly until 30 weeks post-treatment. Results: Comparison of acute skin toxicity following radiation indicated a tissuesparing effect of FLASH compared to conventional single-fraction radiation with a mean protection ratio of 1.40 (1.35-1.46). Fibrotic development similarly indicated normal tissue sparing with a 1.18 (1.17-1.18) protection ratio. The acute skin toxicity tissue sparing was similar to data from entrance-beam irradiations of Sørensen et al. (4). Conclusion: Full dose-response curves for acute and late toxicity after CONV and FLASH radiation were obtained. Radiation within the SOBP retains the normal-tissue-sparing effect of FLASH with a dose-modifying factor of 40% for acute skin damage and 18% for fibrotic development. [ABSTRACT FROM AUTHOR]

In the United States, the Federal Aviation Administration has officially classified flight crews (FC) consisting of commercial pilots, cabin crew, or flight attendants as "radiation workers" since 1994 due to the potential for cosmic ionizing radiation (CIR) exposure at cruising altitudes originating from solar activity and galactic sources. Several epidemiological studies have documented elevated incidence and mortality for several cancers in FC, but it has not yet been possible to establish whether this is attributable to CIR. CIR and its constituents are known to cause a myriad of DNA lesions, which can lead to carcinogenesis unless DNA repair mechanisms remove them. But critical knowledge gaps exist with regard to the dosimetry of CIR, the role of other genotoxic exposures among FC, and whether possible biological mechanisms underlying higher cancer rates observed in FC exist. This review summarizes our understanding of the role of DNA damage and repair responses relevant to exposure to CIR in FC. We aimed to stimulate new research directions and provide information that will be useful for guiding regulatory, public health, and medical decision-making to protect and mitigate the risks for those who travel by air. [ABSTRACT FROM AUTHOR]

Refractory metal single crystals have been applied in key high-temperature structural components of advanced nuclear reactor power systems, due to their excellent high-temperature properties and outstanding compatibility with nuclear fuels. Although electron beam floating zone melting and plasma arc melting techniques can prepare large-size oriented refractory metals and their alloy single crystals, both have difficulty producing perfect defect-free single crystals because of the high-temperature gradient. The mechanical properties of refractory metal single crystals under different loads all exhibit strong temperature and crystal orientation dependence. Slip and twinning are the two basic deformation mechanisms of refractory metal single crystals, in which low temperatures or high strain rates are more likely to induce twinning. Recrystallization is always induced by the combined action of deformation and annealing, exhibiting a strong crystal orientation dependence. The irradiation hardening and neutron embrittlement appear after exposure to irradiation damage and degrade the material properties, attributed to vacancies, dislocation loops, precipitates, and other irradiation defects, hindering dislocation motion. This paper reviews the research progress of refractory metal single crystals from three aspects, preparation technology, deformation behavior, and irradiation damage, and highlights key directions for future research. Finally, future research directions are prospected to provide a reference for the design and development of refractory metal single crystals for nuclear applications. [ABSTRACT FROM AUTHOR]

Background: Fibroblast Activation Protein (FAP)-targeted nanoparticles (NPs) are designed to accumulate in cancerous stroma. These NPs hold promise for imaging applications in cancer therapy. Objective: This systematic review aimed to comprehensively explore the use of FAP-targeting NPs for cancer diagnosis through different imaging modalities. Material and Methods: This systematic review followed the framework proposed by O'Malley and Arksey. Peer-reviewed studies were searched in the Scopus, Science Direct, PubMed, and Google Scholar databases. Eligible studies were selected, and data were extracted to investigate the FAP-targeting NPs in imaging. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was also utilized to present the results. Results: Five studies met the specified inclusion criteria and were finally selected for analysis. The extracted data was classified into two categories: general and specific data. The general group indicated that most studies have been conducted in Mexico and have increased since 2022, and the specific group showed that colorectal cancer and Nude mice have received the most research attention. Furthermore, FAP-targeted NPs have demonstrated superior diagnostic imaging capabilities, even compared to specific methods for each cancer type. Also, they have been safe, with no toxicity. Conclusion: FAP-targeted NPs using different ligands, such as Fibroblast Activation Protein Inhibitor (FAPI), can accurately detect tumors and metastases, and outperform specific cancer peptides like PSMA in cancer diagnosis. They are also non-toxic and do not cause radiation damage to tissues. Therefore, FAP-targeted NPs have the potential to serve as a viable alternative to FAP-targeted radionuclides for cancer diagnosis. [ABSTRACT FROM AUTHOR]

Radon is one of the important natural sources of radiation and pollutants. When radon and its progeny are inhaled by the human body, they can cause radiation damage to the respiratory system and can lead to lung cancer. Indoor and outdoor radon concentrations were measured in five villages near Shizhuyuan W-polymetallic deposit using a RAD7 detector; moreover, the corresponding radiation dose and lifetime risk probability were evaluated. The results show that the average value of indoor radon concentration was 216.6 ± 121.1 Bq m−3, which is above the worldwide average indoor radon level of 40 Bq m−3, and the average outdoor value was 34.6 ± 13.4 Bq m−3, which is higher than the worldwide outdoor average of 10 Bq m−3. A total of 42% of the dwellings investigated in our study had a higher radon level than the Chinese permissible indoor radon level of 200 Bq m−3. The total annual effective dose ranged from 5.21 mSv y−1 to 49.38 mSv y−1, with an average value of 14.63 mSv y−1, which is higher than the ICRP recommended value of 3–10 mSv y−1. This average total dose value corresponds to an average lifetime risk probability of 5.8% for residents in the whole study area. [ABSTRACT FROM AUTHOR]

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New features in the dose estimation program RADDOSE‐3D are summarised. They include the facility to enter a diffraction intensity decay model which modifies the "Diffraction Weighted Dose" output from a "Fluence Weighted Dose" to a "Diffraction‐Decay Weighted Dose", a description of RADDOSE‐ED for use in electron diffraction experiments, where dose is historically quoted in electrons/Å2 rather than in gray (Gy), and finally the development of a RADDOSE‐3D GUI, enabling easy access to all the options available in the program. [ABSTRACT FROM AUTHOR]

N-channel depletion metal oxide semiconductor field effect transistors (MOSFETs) were irradiated with 60Co gamma radiation in the dose range of 100 krad to 6 Mrad at cryogenic (77 K) and room temperatures (300 K). The MOS devices irradiated at 77 K and 300 K were characterized at 77 K and 300 K respectively. The different electrical parameters of MOSFET such as threshold voltage (Vth), density of interface trapped charges (ΔNit), density of oxide trapped charges (ΔNot) and mobility of the charge carriers (μ) were studied as a function of total dose. A considerable increase in ΔNit and ΔNot and decrease in Vth was observed after irradiation. The 77 K irradiation results were then compared with 300 K irradiation results and found that the degradation in the electrical characteristics is more for the devices irradiated at 300 K. [ABSTRACT FROM AUTHOR]

Recently, biomolecular condensates formed through liquid–liquid phase separation have been widely reported to regulate key intracellular processes involved in cell biology and pathogenesis. BRD4 is a nuclear protein instrumental to the establishment of phase-separated super-enhancers (SEs) to direct the transcription of important genes. We previously observed that protein droplets of BRD4 became hydrophobic as their size increase, implying an ability of SEs to limit the ionization of water molecules by irradiation. Here, we aim to establish if SEs confer radiation resistance in cancer cells. We established an in vitro DNA damage assay that measures the effect of radicals provoked by the Fenton reaction on DNA integrity. This revealed that DNA damage was markedly reduced when BRD4 underwent phase separation with DNA. Accordingly, co-focal imaging analyses revealed that SE foci and DNA damage foci are mutually exclusive in irradiated cells. Lastly, we observed that the radioresistance of cancer cells was significantly reduced when irradiation was combined with ARV-771, a BRD4 de-stabilizer. Our data revealed the existence of innately radioresistant genomic regions driven by phase separation in cancer cells. The disruption of these phase-separated components enfolding genomic DNA may represent a novel strategy to augment the effects of radiotherapy. [ABSTRACT FROM AUTHOR]

With the rapid development of hydrogen energy worldwide, the number of hydrogen energy facilities, such as hydrogen refueling stations, has grown rapidly in recent years. However, hydrogen is prone to leakage accidents during use, which could lead to hazards such as fires and explosions. Therefore, research on the safety of hydrogen energy facilities is crucial. In this paper, a study of high-pressure hydrogen jet flame accidents is conducted for a proposed integrated hydrogen production and refueling station in China. The effects of leakage direction and leakage port diameter on the jet flame characteristics are analyzed, and a risk assessment of the flame accident is conducted. The results showed that the death range perpendicular to the flame direction increased from 2.23 m to 5.5 m when the diameter of the leakage port increased from 4 mm to 10 mm. When the diameter of the leakage port is larger than 8 mm, the equipment on the scene will be within the boundaries of the damage. The consequences of fire can be effectively mitigated by a reasonable firewall setup to ensure the overall safety of the integrated station. [ABSTRACT FROM AUTHOR]

3D electron diffraction (3D ED), or microcrystal electron diffraction (MicroED), has become an alternative technique for determining the high‐resolution crystal structures of compounds from sub‐micron‐sized crystals. Here, we considered l‐alanine, α‐glycine and urea, which are known to form good‐quality crystals, and collected high‐resolution 3D ED data on our in‐house TEM instrument. In this study, we present a comparison of independent atom model (IAM) and transferable aspherical atom model (TAAM) kinematical refinement against experimental and simulated data. TAAM refinement on both experimental and simulated data clearly improves the model fitting statistics (R factors and residual electrostatic potential) compared to IAM refinement. This shows that TAAM better represents the experimental electrostatic potential of organic crystals than IAM. Furthermore, we compared the geometrical parameters and atomic displacement parameters (ADPs) resulting from the experimental refinements with the simulated refinements, with the periodic density functional theory (DFT) calculations and with published X‐ray and neutron crystal structures. The TAAM refinements on the 3D ED data did not improve the accuracy of the bond lengths between the non‐H atoms. The experimental 3D ED data provided more accurate H‐atom positions than the IAM refinements on the X‐ray diffraction data. The IAM refinements against 3D ED data had a tendency to lead to slightly longer X—H bond lengths than TAAM, but the difference was statistically insignificant. Atomic displacement parameters were too large by tens of percent for l‐alanine and α‐glycine. Most probably, other unmodelled effects were causing this behaviour, such as radiation damage or dynamical scattering. [ABSTRACT FROM AUTHOR]

A U. S. and European joint effort fostering the development of medical countermeasures (MCMs) operable in case of radiological or nuclear emergencies. Based on the joint engagement between the U.S. National Institute of Allergy and Infectious Diseases (NIAID) and the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN), a Statement of Intent to Collaborate was signed in 2014 and a series of working group meeting were established. In December 2022, the NIAID and IRSN hosted a five-day, U.S./European meeting titled 'Radiation-Induced Cutaneous and Gastrointestinal Injuries: Advances in Understanding Pathologies, Assessment, and Clinically Accepted Practices' in Paris, France. The goals of the meeting were to bring together U.S. and European investigators to explore new research avenues for the medical management of skin and gastrointestinal injuries, including specific diagnostics for each organ system, animal models, and promising medical countermeasures (MCMs) to mitigate radiation damage. There was also an emphasis on exploring additional areas of medicine and response to understand best practices from other emergency scenarios, which could be leveraged to improve radiation preparedness, and the importance of accurate dosimetry in preclinical work. Subsequent to the workshop, seven collaborative projects, funded by both organizations, were established on topics ranging from MCMs and predictive biomarkers, and using physical methods to assess cutaneous radiation injuries, to mechanistic studies to understand radiation-induced damage in multiple organ systems. The importance of accurate dosimetry in preclinical works was highlighted and two recently published U.S./European commentaries that focus on the need for dosimetry standardization in the reported literature had their origins in this meeting. This commentary summarizes the workshop and open discussions among academic investigators, industry researchers, and U.S. and IRSN program representatives. Given the substantive progress made due to these interactions, both groups plan to expand out these meetings by incorporating high-level investigators from across the globe, while endeavoring to maintain the informal setting that was conducive to in-depth scientific discussion and enhanced the state of the science in radiation research. [ABSTRACT FROM AUTHOR]

Nuclear energy is essential for the future development of countries. However, both structural and functional components of nuclear power equipment are facing severe challenges of nuclear irradiation damage after experiencing irradiation growth and irradiation creep. How to avoid irradiation damage to nuclear power equipment has become a hotspot in international research and development of surface protection technology. Deposition of protective coatings on the underlying object surface or in bulk materials has been considered as a near-term solution to enhanc functional components. Different substrate materials are selected according to other service conditions within the reactor. Suitable material selection combined with relevant optimization can significantly increase the service life of materials. This review summarizes recent research on several categories of anti-irradiation coatings prepared by physical vapor deposition technology for current industrial applications. These includes metallic, ceramic, composite and high entropy alloy coatings. The review endeavors to impart a thorough understanding of the properties of these selected anti-irradiation coatings, from the fundamental aspects of their substrate materials to their practical applications across diverse settings. It explores not only the current research progress but also the potential avenues for future advancements. Additionally, the intricate relationships between coating formulations, their resistance to irradiation, and their ultimate performance in various environments are illuminated in this paper.

Ultrahigh-resolution structures provide unprecedented details about protein dynamics, hydrogen bonding and solvent networks. The reported 0.70 Å, room-temperature crystal structure of crambin is the highest-resolution ambient-temperature structure of a protein achieved to date. Sufficient data were collected to enable unrestrained refinement of the protein and associated solvent networks using SHELXL. Dynamic solvent networks resulting from alternative side-chain conformations and shifts in water positions are revealed, demonstrating that polypeptide flexibility and formation of clathrate-type structures at hydrophobic surfaces are the key features endowing crambin crystals with extraordinary diffraction power.

Objective: This study was to investigate the protective effect of Noni polysaccharides on ionizing radiation injury and its regulation of intestinal flora in mice. Methods: Fifty KM male mice were randomly divided into normal group, model group, noni polysaccharide low-dose group, noni polysaccharide medium-dose group and Noni polysaccharide high-dose group. The whole body of the mice was irradiated by the medical electron linear accelerator, thus establishing acute radiation-damaged mice model. Subsequently, survival quality of mice after irradiating was observed, and related biochemical indicators of serum and liver tissue of mice after irradiating for 72 h were detected. Furthermore, 16S rRNA sequencing of mouse feces was performed to analyze diversity of intestinal flora. Results: Noni polysaccharides could improve survival quality of radiation-damaged mice, and increase organ index, peripheral blood leukocyte (WBC) number, spleen nodule number, bone marrow DNA content. Moreover, noni polysaccharides could reduce the rate of bone marrow polychromatic erythrocyte micronucleus (MN-PCE), and increase the activities of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in serum and liver, and reduce malondialdehyde (MDA) content. Compared with the MC group, the increase rate of peripheral white blood cell count and number of splenic noduleswas 46.85%, 38.23%, and the content of bone marrow DNA increased by 51.95%, the reduction rate of MN-PCE was 38.84% of Noni polysaccharide high-dose group. Meanwhile, the oxidative stress of mice after irradiating had improvement in different degree of Noni polysaccharide. Additionally, Noni polysaccharides could promote the growth of intestinal flora of radiation-damaged mice in a direction of beneficial to host health. Meanwhile, Noni polysaccharides could accelerate the growth of probiotics and inhibit the colonization of harmful bacteria, and recover the changes of intestinal flora caused by ionizing radiation. Conclusion: Noni polysaccharides exhibited obvious protective effect on ionizing radiation-damaged mice caused by X-ray, and showed certain restoring effect on intestinal flora disturbance caused by radiation.

Objective To study the effect of the combinational use of miR-34a-functionalized Bio-Oss® bone powder with transglutaminase crosslinked gelatin (Col-Tgel) on the osteoblastic differentiation of bone marrow mesenchymal stem cells (BMSCs) and bone defect healing after irradiation. Methods The experiment was approved by the Animal Ethics Committee. BMSCs were isolated from the bone marrow of 2-week-old Sprague-Dawley (SD) rats and identified. After reaching 80% confluence, BMSCs were irradiated with 2 Gy of X-ray radiation to establish a radiation-damaged BMSC model for further experimentation. 2.5 μL or 5 μL of Col-Tgel was mixed with 10 mg of Bio-Oss® (P) to prepare PG-2.5 and PG-5. The optimal proportion of Bio-Oss® (P) and Col-Tgel was determined through in vitro and in vivo experiments. Cy3-labeled agomiR-34a, agomiR-34a, or agomiR NC was mixed with lipofectamine 2000 and added to 10 mg of Bio-Oss® (P). The mixtures were lyophilized, and 2.5 μL Col-Tgel was added to each group of lyophilized Bio-Oss®/lipofectamine/miRNA complexes or to 10 mg of Bio-Oss® to obtain PG-Cy3-miR-34a, PG-miR-34a, PG-miR NC, and PG. Irradiated BMSCs were cocultured with PG-Cy3-miR-34a to evaluate cellular uptake of Cy3-agomiR-34a using confocal microscopy. Then, irradiated BMSCs were cocultured with PG-miR-34a, PG-miR NC, and PG. The expression of miR-34a was tested by RT-qPCR and cell proliferation was tested by CCK-8 assay. After 14 days of osteogenic induction, the mRNA expression of Runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), and osteocalcin (OCN) was tested by RT-qPCR. The bilateral tibias of 8-week-old SD rats were irradiated with a single dose of 15 Gy of X-ray radiation. Three weeks later, tibial defects with a diameter of 3 mm and a depth of 2 mm were created 2-3 mm below the epiphyseal line in the tibial metaphysis. The composite bone substitute materials of PG-miR-34a, PG-miR NC, and PG were implanted into the defect area. Eight weeks after implantation, the tibias were harvested and evaluated for bone regeneration using micro-CT analysis and HE staining. Results The results demonstrated that 2 Gy irradiation adversely affected the osteogenic differentiation capacity of BMSCs, evidenced by the decreased ALP staining and number of mineralized nodules stained with Alizarin red in the irradiated group compared to the non-irradiated group. The composite material consisting of 10 mg Bio-Oss® and 2.5 μL Col-Tgel exhibited good osteogenic induction capability and handling properties and was used for subsequent experiments. The PG-Cy3-miR-34a could deliver the loaded Cy3-agomiR-34a into irradiated BMSCs. PG-miR-34a enhanced the expression of miR-34a in irradiated BMSCs without affecting cell proliferation. PG-miR-34a significantly upregulated the expression of osteogenic-related genes, including Runx2, ALP, and OCN. In the experiment of bone defect healing in irradiated tibias, micro-CT analysis showed that PG-miR-34a group had a higher bone volume in the bone defect area compared to other groups. The HE staining results also confirmed that implantation of PG-miR-34a can promote the healing of bone defects in irradiated tibias. Conclusion The combinational use of miR-34a-functionalized Bio-Oss® bone powder with Col-Tgel could promote the osteogenic differentiation of irradiated BMSCs and enhance bone regeneration in irradiated bone defects.

Grain boundary (GB) failure in tungsten under shock loading after irradiation is a key factor to estimate the performance of tungsten as a plasma facing material in nuclear fusion reactors and as a target in spallation neutron sources. In this work, GB evolution after absorption of different radiation defect clusters under shock loading has been investigated at atomic scale through non-equilibrium molecular dynamics (NEMD) method. Different to the cases without radiation defects, after absorption of interstitial dislocation loops and voids, two mechanisms have been identified for the decrease of critical shock velocity (vc) and the related GB failure. The direct void growth accompanied by appearance of disordered structure around void, from the remaining vacancy cluster which could not be annihilated by compressive stress wave, is the 1st mechanism. In the 2nd mechanism, activation of slip systems, dislocation formation, motion and multiplication, void nucleation and growth dominate the failure process. The higher potential energy and local stress concentration around a defect absorption region in GB are recognized for atomic motion deviations from shock loading direction, resulting in formation of disordered structure, activation of slip system and dislocation multiplication with lower vc under coupling effects of radiation damage and shock loading. These results indicate that under a high dose of radiation damage, GB failure induced by shock loading should be considered seriously in order to estimate the lifetime of tungsten-based plasma facing materials and spallation target materials.

In this paper, an effective equivalent modeling technique has been proposed to describe small-signal characteristics of InP-based high electron mobility transistors (HEMTs) after proton radiation, which is composed of an artificial neural network and equivalent-circuit models. Small-signal intrinsic parameters of InP-based HEMTs are extracted from S-parameters before and after 2 MeV proton radiation as modeling objects. The deep learning model of a generative adversarial network has been explored to expand the measured finite data samples. Four feedforward neural networks are incorporated to equivalent-circuit topology to form the equivalent model, which are trained to accurately predict the radiation-induced variations of Cgs, Cgd, Rds, and gm, respectively. The prediction accuracy of the developed equivalent model has been well verified in terms of the broad-band S-parameters under radiation fluence of 1 × 1014 and 5 × 1013 H+/cm2. This equivalent modeling method with characterization of radiation damage effects could provide significant guidance for the aerospace monolithic millimeter-wave integrated circuit design. [ABSTRACT FROM AUTHOR]

This work is devoted to calculating the rate of radiation damage production in a uranium target irradiated with high-energy electrons with an energy of 100 MeV. The Monte Carlo program MCNPX was used to perform a complete mathematical modeling of a complex of processes occurring in a uranium target when irradiated with high-energy electrons: the development of an electromagnetic shower, the production of photoneutrons, the transport of particles in the target and the creation of radiation damage in it. The analysis showed that fragments of U-238 photo-fission give the main input into the rate of damage production in a uranium target which reaches the value of 100 dpa/year. The expected service life of a uranium target under irradiation is 3 years of operation at full accelerator power.

An X-ray absorption spectroscopy (XAS) electrochemical cell was used to collect high-quality XAS measurements of N-truncated Cu:amyloid-β (Cu:Aβ) samples under near-physiological conditions. N-truncated Cu:Aβ peptide complexes contribute to oxidative stress and neurotoxicity in Alzheimer's patients' brains. However, the redox properties of copper in different Aβ peptide sequences are inconsistent. Therefore, the geometry of binding sites for the copper binding in Aβ4–8/12/16 was determined using novel advanced extended X-ray absorption fine structure (EXAFS) analysis. This enables these peptides to perform redox cycles in a manner that might produce toxicity in human brains. Fluorescence XAS measurements were corrected for systematic errors including defective-pixel data, monochromator glitches and dispersion of pixel spectra. Experimental uncertainties at each data point were measured explicitly from the point-wise variance of corrected pixel measurements. The copper-binding environments of Aβ4–8/12/16 were precisely determined by fitting XAS measurements with propagated experimental uncertainties, advanced analysis and hypothesis testing, providing a mechanism to pursue many similarly complex questions in bioscience. The low-temperature XAS measurements here determine that CuII is bound to the first amino acids in the high-affinity amino-terminal copper and nickel (ATCUN) binding motif with an oxygen in a tetragonal pyramid geometry in the Aβ4–8/12/16 peptides. Room-temperature XAS electrochemical-cell measurements observe metal reduction in the Aβ4–16 peptide. Robust investigations of XAS provide structural details of CuII binding with a very different bis-His motif and a water oxygen in a quasi-tetrahedral geometry. Oxidized XAS measurements of Aβ4–12/16 imply that both CuII and CuIII are accommodated in an ATCUN-like binding site. Hypotheses for these CuI, CuII and CuIII geometries were proven and disproven using the novel data and statistical analysis including F tests. Structural parameters were determined with an accuracy some tenfold better than literature claims of past work. A new protocol was also developed using EXAFS data analysis for monitoring radiation damage. This gives a template for advanced analysis of complex biosystems.

Desired modifications of surfaces at the nanoscale may be achieved using energetic ion beams. In the present work, a complete study of self-assembled ripple pattern fabrication on Si and Ge by 100 keV Ar+ ion beam bombardment is discussed. The irradiation was performed in the ion fluence range of ≈3 × 1017 to 9 × 1017 ions/cm2 and at an incident angle of θ ≈ 60° with respect to the surface normal. The investigation focuses on topographical studies of pattern formation using atomic force microscopy, and induced damage profiles inside Si and Ge by Rutherford backscattering spectrometry and transmission electron microscopy. The ripple wavelength was found to scale with ion fluence, and energetic ions created more defects inside Si as compared to that of Ge. Although earlier reports suggested that Ge is resistant to structural changes upon Ar+ ion irradiation, in the present case, a ripple pattern is observed on both Si and Ge. The irradiated Si and Ge targets clearly show visible damage peaks between channel numbers (1000–1100) for Si and (1500–1600) for Ge. The clustering of defects leads to a subsequent increase of the damage peak in irradiated samples (for an ion fluence of ≈9 × 1017 ions/cm2) compared to that in unirradiated samples.

This study presents a radiation-induced thermal conductivity degradation (TCD) model of zirconium as compared to the conventional UO2 TCD model. We derived the governing factors of the radiation-induced TCD model, such as maximum TCD value and temperature range of TCD. The maximum TCD value was derived by two methods, in which 1) experimental result of 32 % TCD was directly utilized as the maximum TCD value and 2) a theoretical approach based on dislocation was applied to derive the maximum TCD value. Further, the temperature range of TCD was determined to be 437–837 K by 1) experimental results of post-annealing of irradiation hardening as compared to 2) the rate theory and thermal equilibrium. Consequently, the radiation-induced TCD model of zirconium was derived to be fr=1−0.321+exp⁡{(T−637)/45} . Because the thermal conductivity of zirconium is one of the factors determining the storage and transport system, this newly proposed model could improve the safety analysis of spent fuel storage systems.

DNA double-strand breaks (DSBs), such as those produced by radiation and radiomimetics, are amongst the most toxic forms of cellular damage, in part because they involve extensive oxidative modifications at the break termini. Prior to completion of DSB repair, the chemically modified termini must be removed. Various DNA processing enzymes have been implicated in the processing of these dirty ends, but molecular knowledge of this process is limited. Here, we demonstrate a role for the metallo-β-lactamase fold 5′−3′ exonuclease SNM1A in this vital process. Cells disrupted for SNM1A manifest increased sensitivity to radiation and radiomimetic agents and show defects in DSB damage repair. SNM1A is recruited and is retained at the sites of DSB damage via the concerted action of its three highly conserved PBZ, PIP box and UBZ interaction domains, which mediate interactions with poly-ADP-ribose chains, PCNA and the ubiquitinated form of PCNA, respectively. SNM1A can resect DNA containing oxidative lesions induced by radiation damage at break termini. The combined results reveal a crucial role for SNM1A to digest chemically modified DNA during the repair of DSBs and imply that the catalytic domain of SNM1A is an attractive target for potentiation of radiotherapy. Broken chromosomes are lethal to cells with breaks ends often containing complex DNA damage. Here, the authors reveal a key role for the SNM1A enzyme in cleaning up break ends. Key anticancer drugs, and therapeutic radiation produce complex DNA breaks, making SNM1A an appealing therapeutic target. [ABSTRACT FROM AUTHOR]