Radiation Damage Research Articles (Page 3)

One of the most urgent and significant issues in modern medicine and veterinary science is the protection of humans and animals from radiation damage, as well as the development of effective and safe methods of nootropic therapy. The main goal of scientific research conducted in this area is to determine 154ways to protect living organisms from the harmful effects of ionizing radiation and to minimize its consequences. In the first stage of the study, an experiment was conducted under laboratory conditions using 30 laboratory mice. Hematological analysis showed that all blood parameters were within physiological norms, indicating no significant abnormalities in body systems at the initial stage of the experiment. In the second stage, the effectiveness of removing radionuclides from the bodies of rats using natural sorbents based on shungite and bentonite was evaluated. During this phase, the level of radionuclide elimination and the time of residual dose load formation in the gastrointestinal tract and critical organs were determined at 5, 15, 30, and 60 minutes. As a result, the group that received sorbents showed significantly lower accumulation of radiopharmaceutical substances: after 5 minutes –4.48%, after 15 minutes –2.0%, after 30 minutes –1.35%, and after 60 minutes –1.04%

High-energy (710 MeV) Bi ion track morphology in polycrystalline silicon nitride was investigated during post-irradiation annealing. Using both in-situ and ex-situ transmission electron microscopy, we monitored the recovery of crystallinity within initially amorphous ion track regions. In-situ annealing involved heating samples from room temperature to 1000 °C in 50 °C increments, each held for 10 s. We observed a steady decrease in both the size and number of tracks, with only a small number of residual crystalline defects remaining at 1000 °C. Ex-situ annealing experiments were conducted at 400 °C, 700 °C, and 1000 °C for durations of 10, 20, and 30 min. Complete restoration of the crystalline lattice occurred after 30 min at 700 °C and 20 min at 1000 °C. Due to inherent differences in geometry, heat flow, and stress conditions between thin lamella and bulk specimens, in-situ and ex-situ results cannot be compared. Molecular dynamics simulations further revealed that track shrinkage begins in cells within picoseconds, supporting the notion that recrystallization can start on very short timescales. Overall, these findings demonstrate that thermal recrystallization of damage induced by swift heavy ion irradiation in polycrystalline Si3N4 is possible. This study provides a foundation for future research aimed at better understanding radiation damage recovery in this material.

This study employs in situ transmission electron microscopy (TEM) to investigate the dynamic evolution of radiation-induced defects in gallium nitride (GaN) under high temperature (800 °C). The results demonstrate that defect cluster size increases progressively with irradiation dose (up to 2.48 displacements per atom, dpa), while cluster density exhibits a non-monotonic trend, peaking at intermediate doses (0.31–0.62 dpa) before declining due to coalescence of smaller clusters. Aberration-corrected scanning TEM reveals that irradiation generates dislocations, stacking faults, and cavities. Besides, N2 bubbles nucleate even at ultralow doses (0.02 dpa), driven by interstitial N aggregation and vacancy capture. Despite significant radiation damage, GaN maintains its crystalline structure without amorphization at high doses. Besides, there is negligible aggregation of defects around intrinsic dislocations—a behavior attributed to the high migration energy barriers of vacancies and interstitials in GaN. These findings elucidate the intrinsic radiation resistance mechanisms of GaN through atomic-level defect dynamics, providing critical guidance for designing next-generation radiation-tolerant power electronics and radiation detectors in extreme environments such as nuclear reactors and space applications.

Martin C. (Marty) Mihm made multiple, pivotal contributions over four decades of discovery, innovation, and development leading to the world-wide application of lasers in dermatology. This started with trying to understand how pulses of light could be tailored to affect microscopic "target" structures in skin where the light is absorbed. There were many surprises, often first observed by light or electron microscopy. A host of new capabilities ensued, including laser treatments for microvascular and vascular malformations, non-melanoma pigmented lesions, tattoo and hair removal, rehabilitation of scars, improvement of photoaged skin, and lipid-targeting lasers for reduction of fat and acne. Dr. Mihm extended himself directly to patients, especially children with vascular anomalies. He contributed to the discovery that GLUT1, a glucose transporter expressed on vascular endothelium, is a defining diagnostic for infantile hemangiomas. He established a multispecialty vascular-anomalies clinic at the Massachusetts General Hospital, and co-founded the Vietnam Vascular Anomalies Center (VVAC) in Ho Chi Minh City. In Vietnam, topical radioactive phosphorus (32P) is applied as a misguided treatment for infantile hemangiomas, leading to radiation damage in uncounted thousands of children. By teaching the use of beta-adrenergic drug treatment, the use of 32P has been greatly reduced. Dr. Mihm pioneered the concept of pulsed dye laser (PDL) in combination with angiogenic inhibitors to improve the clinical efficacy of port wine stain (PWS) treatment. Moreover, he made seminal contributions to our understanding of the pathogenesis and spectrum of phenotypes of PWS lesions. The legacy of Martin C. Mihm extends to the entire world.

The formation of various DNA base modifications is one of the significant consequences of the action of ionizing radiation on biological systems. These modifications can alter the conformation of damaged fragments and change their interaction with oncoming nucleotides during biosynthesis. In this work, the consequences of the formation of 8-oxo-guanine (OG) and 5-formyl-cytosine (fC) in the DNA structure are considered. The structural and genetic experimental data available in the literature for these modifications is analyzed in comparison to the MM and QM results obtained for the simple fragments of damaged DNA. The computations shed light on how the change in the interaction energy between subunits due to the radiation damage alters their biological function. The existence of OG nucleoside in both anti- and syn- base sugar orientations explains its high mutagenicity. The anti- conformation supports the formation of an OG pair with cytosine, resembling the canonical G:C pair with three hydrogen bonds (H-bonds), while the syn- conformation can form mispairs with purines, both outcomes having the energy and structural characteristics favorable for insertion into the duplex. The H-bonded pair of fC with guanine resembles that of an intact base, and the minor probability of formation of mispairs leads to marginal mutagenicity of fC.

Bismuth and Lead are commonly used for radiation shielding to mitigate risks such as radiation damage and cancer. However, these materials are costly and impractical for certain applications. This study aims to explore the attenuation properties of various elements and composites using Monte Carlo simulations to develop improved radiation shielding materials. GAMOS software was employed to simulate materials with thicknesses ranging from 0.1 to 2.0 mm and x-ray energies between 10 and 150 keV. Initial simulations focused on validating bismuth and lead by calculating their mass attenuation coefficients, which matched NIST (National Institute of Standards and Technology) values within a 2% margin of difference. After verification, the study simulated various shielding materials incorporating metals and rare earth elements. Among these, four composites with rare earth elements demonstrating the highest mass attenuation coefficients were selected. These composites exhibited superior absorption in the 50–80 keV energy range compared to bismuth and lead.

Purpose: To explore the efficacy and safety of 125I source implantation via a coaxial puncture in treating locally advanced pancreatic cancer (LAPC). Methods: A retrospective analysis was used to investigate the efficacy and safety of 40 patients with LAPC treated with radioactive 125I particles under CT guidance in the hospital. A treatment planning system was used to develop the preoperative plan, and the radioactive 125I particles were implanted using a coaxial puncture technique in the same plane to simulate a sector distribution system. CT scans were performed at postoperative months 2, 4, and 6 for follow-up treatment outcome assessment. Overall survival (OS) time and progression-free survival (PFS) were calculated, and factors affecting prognosis were assessed. Results: All patients completed the operation successfully. The overall response rate of treatment at 2, 4, and 6 months was 37.5%, 47.5%, and 50.0%. The median OS and PFS were 11.0 months (95% confidence interval [CI]: 9.14-12.86) and 9.0 months (95% CI: 7.45-10.55), respectively. The 6- and 12-month PFS rates were 85.0% (95% CI: 69.6%-93.0%) and 35.0% (95% CI: 20.8%-49.5%), respectively. The 12-month OS rates were 47.5% (95% CI: 20.2%-49.8%). The intraoperative complications related to the operation were local abdominal hemorrhage in 2 cases, subcutaneous soft tissue hematoma in 2 cases, and wrong puncture of the pancreatic duct in 1 case. The main side-effects were fever in 10 cases and decreased appetite in 3 cases in the recent postoperative period. Eighteen grade 0 cases and 3 cases of grade I acute radiation enteritis occurred. No acute radiation damage above grade II and late radiation damage was observed. Conclusions: Coaxial puncture 125I source implantation is a promising percutaneous minimally invasive technology that is safe and effective in treating LAPC.

This study investigates the effects of varying tritium breeding materials and their lithium enrichment rates on the Tritium Breeding Ratio (TBR) and Energy Multiplication Factor (M) within the tritium breeding zone of a fusion reactor. The magnetic fusion reactor model was developed based on the geometric and plasma parameters of the International Thermonuclear Experimental Reactor (ITER), ensuring a realistic representation of current fusion reactor designs. ITER‑grade stainless steel (SS 316 LN‑IG) was selected as the first wall material due to its excellent mechanical properties, high resistance to radiation damage, and compatibility with high‑temperature environments. The coolant and tritium breeding materials considered in the blanket included natural lithium, lithium fluoride (LiF), FLiBe (LiF‑BeF2), and FLiNaBe (LiF‑NaF‑BeF2). These materials were chosen for their ability to facilitate tritium breeding while maintaining thermal and neutronic efficiency. Neutron transport calculations and geometric modeling were performed using the widely recognized 3D simulation tools MCNP 5 and TopMC, which employ the continuous‑energy Monte Carlo method. The simulations utilized built‑in continuous‑energy nuclear and atomic data libraries, along with the Evaluated Nuclear Data File (ENDF) system (ENDF/B‑V and ENDF/B‑VI), ensuring reliable and validated results. The results highlight the importance of material selection and enrichment optimization in achieving efficient tritium breeding and energy production. FLiBe, in particular, shows promise for future fusion reactor designs due to its superior performance in terms of TBR and M. These findings provide valuable insights for the development of sustainable and high‑performance fusion reactors, contributing to the global pursuit of clean and virtually limitless energy.

Abstract Uranium mononitride (UN) is a promising accident-tolerant fuel because of its high fissile density and high thermal conductivity. In this study, we developed the first machine learning interatomic potentials for reliable atomic-scale modeling of UN at finite temperatures. We constructed a training set using density functional theory (DFT) calculations that was enriched through an active learning procedure, and two neural network potentials were generated. Both potentials successfully reproduce key thermophysical properties of interest, such as temperature-dependent lattice parameter, specific heat capacity, and bulk modulus. We also evaluated the energy of stoichiometric defect reactions and defect migration barriers and found close agreement with DFT predictions, demonstrating that our potentials can be used for modeling defects in UN. Additional tests provide evidence that our potentials are reliable for simulating diffusion, noble gas impurities, and radiation damage.

Cryo-electron microscopy single particle analysis (cryo-EM SPA) is the most powerful technique for biomacromolecule structure determination. However, many factors such as complicated noise and radiation damage make the quality of cryo-EM images extremely poor, where high-frequency structure details are submerged, limiting the application of deep learning and suppressing the resolution of reconstruction. Thus, image restoration is of vital importance. Some related works explore micrograph restoration, but the particles in restored micrographs are still of poor quality. Moreover, the training approach of existing methods uses noisy observations or simulated data as supervision, leading to reduced performance on real cryo-EM data. In this paper, we define the task of particle restoration and propose a novel 4-step framework to this end. Labels are created for each particle image and paired data is collected within our framework, compensating for the absence of ground truth. A deep neural network with encoder-decoder architecture is designed to learn the mapping from degraded particles to high-quality ones, while other networks can also be employed as a plug-and-play module. Three datasets are constructed from real cryo-EM data and extensive experiments are carried out. Both quantitative metrics and qualitative visualization indicate that our framework is effective for cryo-EM particle restoration. It becomes easier to extract particle features after restoration, aiding in SPA and the effective application of deep learning on cryo-EM images. The downstream task experiments of cryo-EM SPA are also conducted, showing that the proposed framework has the potential to improve cryo-EM SPA performance.

Surgical resection or liver transplantation is the cornerstone of curative treatment for hepatoblastoma (HBL). For unresectable HBL, liver transplantation has proven to be a definitive curative option, with long-term survival rates ranging from 30 to 95% in previous studies. However, some patients may not meet the surgical or medical criteria for transplantation. Traditionally, radiotherapy (RT) has not been a standard treatment for HBL due to the risk of high-dose radiation damage to normal liver tissue. Proton beam therapy (PBT), a type of RT, leverages the Bragg peak phenomenon, concentrating the majority of its energy within the last few millimeters of its range. This results in a significantly reduced radiation dose beyond this point, thereby minimizing potential harm to distal radiosensitive structures. PBT has emerged as an alternative treatment option for hepatocellular carcinoma in non-surgical adult patients, but its effects and post-treatment changes in HBL remain under-documented. In this preliminary investigation, we aimed to examine the post-PBT following imaging changes in both HBL and the surrounding liver parenchyma in pediatric patients. What Is Known: • HBL is the most common primary malignancy of liver in children. • In HBL, liver transplantation is indicated for patients with tumors that cannot be managed by surgical resection. What Is New: • PBT may prove to be a promising treatment option for unresectable HBL, with the potential to preserve normal liver tissue. • Understanding the imaging changes in post-PBT tumors and the associated focal liver reaction at various time points is crucial for accurately assessing treatment response and guiding appropriate alternative treatment options.

SUMMARYEwing sarcoma (EwS) is a group of bone and soft tissue cancers in children and young adults. Since EwS cells have pronounced sensitivity to radiation and chemotherapy-induced DNA damage, the role of the oncoprotein, EWS-FLI1, in DNA repair is likely. Here, we demonstrate that EWS-FLI1 causes a defect in microhomology-mediated end-joining (MMEJ) repair. EWSR1 is a splicing factor that promotes the faithful splicing of the POLQ pre-mRNA, required for the expression of POLΘ, a critical protein in the MMEJ pathway. Expression of EWS-FLI1, or loss of EWSR1, causes exon 25 skipping of the POLQ transcript, decreased POLΘ expression, impaired MMEJ, and cellular sensitivity to inhibitors of the Fanconi Anemia (FA), NHEJ, or HR pathways, through the mechanism of synthetic lethality. Knockdown of EWS-FLI1 expression restores POLΘ mitotic foci and increases MMEJ activity. Inhibitors of the FA, NHEJ, or HR therefore may provide a targeted therapy for patients with EwS.

Abstract This study explore the radiation damage effects on GaInP/GaAs heterojunction (HJT) solar cells when subjected to 1 MeV electron irradiation. Light I-V measurements show that V oc , J sc and Pmax of the cells exhibit a logarithmic degradation pattern with increasing electron irradiation fluence. Under identical irradiation conditions, the degradation of J sc is substantially less pronounced than that of V oc . Under the same conditions, the heterojunction cell shows better radiation resistance, mainly as its V oc degradation rate with fluence increase is lower than the homojunction cell. Spectral response analysis reveals that 1 MeV electron radiation mainly causes long-wave zone damage in the GaInP/GaAs HJT cells, which intensifies as irradiation fluence accumulates. Dark characteristic analysis indicates that both recombination and diffusion currents in the cells rise with increasing irradiation fluence, with recombination current dominating the dark current. Deep level transient spectroscopy tests show that 1 MeV electron irradiation introduces four defects (H1-H4) in the cells, located at H1(E v +0.717 eV)/H 4 * (E v +0.744 eV), H2(E v +0.369 eV), H3(E v +0.282 eV) and H4(E v +0.032 eV). Among these, the concentration H1 of defects increases most drastically with fluence and directly correlates with the rapid degradation of cell performance under high fluence, making it the crucial factor responsible for the swift degradation of GaInP/GaAs HJT cells under high fluence 1 MeV electron irradiation.

The effectiveness of radiation therapy can be enhanced by understanding the fragmentation mechanisms of iodine-doped DNA oligonucleotide under tender X-rays, as explored experimentally and computationally in our study. By primarily targeting iodine atoms above their L-edge ionization energies, we observed a significant increase in the production of fragments critical to DNA backbone breakage, particularly within mass ranges associated with phosphate and sugar groups. The mass spectroscopy experiments demonstrated that iodine-doped DNA oligonucleotides undergo intense fragmentation at long distances from the initial photoactivation site. Born–Oppenheimer based molecular dynamics simulations confirmed the generation of numerous small fragments, including reactive oxygen species, which are pivotal in enhancing the radiation damage. These findings highlight the effectiveness of iodine doping in amplifying DNA damage in radiotherapy via iodine photoactivation, thereby improving the potential for targeted cancer treatment.

The China Fusion Engineering Demo Reactor (CFEDR) aims to demonstrate the fusion power output for electricity generation under the condition of tritium self-sufficiency, and it relies on an essential component (i.e. a blanket) to achieve this goal. In this present physics design stage, according to the constraints on the geometry and design objectives of CFEDR, both candidate blankets, namely a water-cooled ceramic breeder (WCCB) blanket and a supercritical carbon dioxide (S-CO2) cooled lithium–lead (COOL) blanket, are independently designed with evaluation of their neutronics and thermal hydraulic performance. For nuclear performance, the tritium breeding capability, neutron irradiation damage as well as the shielding performance on the toroidal field coil and vacuum vessel are comprehensively analyzed. In addition, the divertor blanket is also adopted to study its contribution to the tritium breeding ratio (TBR) increment. As part of the design optimization, the thickness of tungsten is further increased to investigate its effects on reduction of the TBR, with the aim of finding the optimal thickness in conjunction with plasma corrosion. Furthermore, thermal hydraulic and magnetohydrodynamics analyses are performed appropriately for WCCB and COOL blankets, respectively, aiming to verify that the coolant can safely remove the nuclear heat and plasma-facing heat flux without the material temperature exceeding the upper limits. The preliminary results will provide effective guidance for the subsequent detailed engineering design of the blanket.

Reduced-activation ferritic-martensitic steel (RAFM), such as F82H, is used in the Fusion Energy System Studies–Fusion Nuclear Science Facility as a structural material for the blanket. Previous research has identified significant issues with corrosion and tritium permeation due to the liquid metal Pb-17Li. To address these issues, aluminum or aluminum-based coatings have been proposed. This study performs a neutronics analysis of a blanket incorporating an aluminum-based coating layer, evaluating parameters such as tritium breeding ratio, nuclear heating (neutron and photon), and radiation damage. Low volume percentages (0.1% to 1.25%) of aluminum or FeAl are mixed with RAFM steel, and the analysis is conducted using OpenMC with the FENDL-3.2b library. The results show that the impact of the aluminum-based coating on these parameters is minimal, with changes within 0.6% compared to the non-coated case. Additionally, given that aluminum contains a long-lived isotope, Aluminum-26, an activation analysis was performed to evaluate its specific activity.

Abstract High‐temperature annealing remains the primary technique for mitigating radiation damage in electronic devices. In this study, a novel alternative is demonstrated that is capable of operating at room temperature within minutes, specifically targeting GaN high‐electron‐mobility transistors (HEMTs). These devices inherently possess defects introduced during fabrication, largely due to lattice and thermal mismatches. It is hypothesized that such defects serve as nucleation sites for radiation‐induced damage. To address this, two strategies are introduced for rapid, room‐temperature annealing based on the Electron Wind Force (EWF). The first, preemptive annealing, reduces native defects in pristine devices prior to irradiation. The second, restorative annealing, repairs devices following radiation exposure. DC and pulsed characterization results show that preemptively annealed HEMTs exhibit enhanced post‐irradiation performance—surpassing even unirradiated counterparts—while restorative EWF treatment rejuvenates damaged devices, often restoring electrical characteristics beyond their original state. In contrast, conventional thermal annealing at 400 °C for over 8 h not only fails to recover device performance but further degrades it, likely due to thermo‐elastic stress. These findings position EWF annealing as a faster, more effective, and thermally efficient solution for defect mitigation and radiation damage recovery in GaN HEMTs.

This study investigates the effects of ultrasmall (∼4nm)gold nanoparticles (AuNPs) combined with X-ray irradiation to enhanceradiotherapy efficacy. Using the in vivo Drosophilamelanogaster model, we observed that while AuNPs alonedelayed embryonic development, their combination with irradiationcompletely halted it. Lifespan analysis showed that irradiated fliesfed with AuNPs had a slight survival advantage, suggesting a protectiveeffect against radiation-induced oxidative stress. Immunofluorescenceanalysis revealed increased DNA damage (or repair) in the flies, supportingthe potential of AuNPs to boost the local radiation dose and offerprotection against radiation-induced damage, with implications foroptimized therapeutic strategies.

Abstract: Radiation therapy is a cornerstone of cancer treatment, yet its efficacy is often compromised by severe side effects that damage healthy tissues, leading to significant patient discomfort and treatment interruptions. Inspired by the extraordinary resilience of tardigrades, microscopic organisms capable of surviving extreme conditions, researchers have developed a novel approach to mitigate radiation-induced damage. This study focuses on the tardigrade-derived protein Dsup (Damage suppressor), which protects DNA from radiation. By delivering messenger RNA (mRNA) encoding the damage suppressor (Dsup), a DNA-binding protein found in tardigrades, via specialized nanoparticles, scientists have successfully reduced radiation-induced DNA damage in mouse models by up to 50%. The localized and temporary expression of Dsup ensures that healthy tissues are protected without compromising the effectiveness of radiation on tumors. This innovative strategy not only enhances the safety and tolerability of radiation therapy but also holds promise for broader applications, potentially relevant in other high-radiation exposure scenarios, such as chemotherapy or space missions. However, these applications remain to be thoroughly investigated. The research conducted by a collaborative team from MIT, Brigham and Women';s Hospital, and the University of Iowa represents a significant advancement in cancer treatment, offering a potential paradigm shift in how we approach radiation damage mitigation. Future efforts will focus on optimizing the delivery system and adapting the Dsup protein for human use, paving the way for clinical trials and real-world applications. This breakthrough underscores the potential of bio-inspired solutions in addressing complex medical challenges.

The high levels of flux at a fourth-generation synchrotron are shown to have significant beam heating effects with increasing risk of radiation damage X-ray crystallography technique is widely used to determine the three-dimensional structures of macromolecules and it is very important to know and how it might affect an X- ray diffraction experiments and the resulting structures. There are two types of radiation damages (global and specific).The radiation damage process is dose dependent and there is no technique available to prevent. X- ray crystallography can be used to monitor the damages by collecting consecutive data sets in the same protein crystal to track the progression of damages. Damage incurred during data collection in macromolecular crystallography (MX) limits the information that can be obtained from a single crystal, and it may also prevent getting the solution of structure. Each year, hundreds of scientists are using SER-CAT to conduct X-ray diffraction experiments many of which are directly related to human diseases. Their efficiency and quality of the data collected for various high impact scientific projects will be depending upon the how precisely we study this radiation damage and provide a general data collection strategy especially for the increased intensity (after APS-U) to SER-CAT user community. To study the consequences and progression of radiation damages, 10 consecutive datasets were collected using single trypsin crystal and analyzed. The results for both global and specific damage effects will be presented.