Search Results (145)

This paper reports the results of a system-level total ionizing dose (TID) effect simulation study on a SMIC 130 nm LEON2 processor. Firstly, the device-level simulations of the 130 nm NMOS transistors are performed using the Sentaurus TCAD software to analyze the effects of a bias condition, channel width, and irradiation dose on a TID-induced leakage current. Based on the TCAD simulation results, a Verilog-A-based compact model is developed for NMOS transistors to describe the TID-induced leakage current, and it is then embedded into target nodes of the SPICE netlist for the LEON2 processor, enabling system-level TID simulations. The simulation results reveal the processor’s failure threshold and corresponding failure mechanism; meanwhile, the increase in the power supply current with the irradiation dose is also observed. The research reported in this paper can provide beneficial guidance for radiation performance evaluation and radiation hardening by design (RHBD) in 130 nm bulk CMOS processors. Full article

This paper focuses on FinFET transistors. The degradation characteristics of FinFET devices after total ionizing dose (TID) radiation in low-temperature environments were investigated by means of a combination of experiments and TCAD simulations. By analyzing the electronic properties of radiation-induced defects in FinFET transistors under low-temperature conditions, the formation and evolution mechanisms of these defects are studied. A physical model for the low-temperature total dose effects of FinFET transistors is established, providing support for the radiation hardening and space applications of FinFET devices. Full article

Background/Objectives: The breast is a highly radiosensitive organ that is directly exposed to ionizing radiation during chest computed tomography (CT) examinations. Excessive radiation exposure increases the risk of radiation-induced malignancies, highlighting the importance of accurate and patient-specific dose estimation. This study aims to estimate the effective radiation dose absorbed by the breast during chest CT examinations using a machine learning (ML)-based personalized prediction approach. Methods: In this retrospective study, a total of 653 female patients who underwent both mammography and chest CT between 2020 and 2024 were included. A structured database was created incorporating demographic and anatomical parameters, including body weight, height, body mass index (BMI), and breast thickness (mm) obtained from mammography, along with dose length product (DLP) values from chest CT scans. Five regression-based ML algorithms—CatBoost, Gradient Boosting, Extra Trees, AdaBoost, and Random Forest—were implemented to predict breast radiation dose. Model performance was evaluated using Mean Squared Error (MSE), Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE), and the Coefficient of Determination (R²). Results: Among the evaluated models, the CatBoost algorithm optimized with Particle Swarm Optimization (CatBoostPSO) achieved the best overall predictive performance, yielding the lowest MSE (0.3795), MAE (0.3846), and MAPE (4.37%), along with the highest R² value (0.9875). CatBoost and Gradient Boosting models demonstrated predictions most closely aligned with ground truth values, indicating that ensemble-based and dynamically optimized models are particularly effective for breast dose estimation. Conclusions: The proposed machine learning framework enables rapid, accurate, and clinically applicable estimation of breast radiation dose during chest CT examinations. This patient-specific approach has strong potential to support personalized radiation dose monitoring and optimization strategies, contributing to improved radiation safety in clinical practice. Full article

It is well known that the space radiation environment, which has contributions from the trapped particles within the Van Allen belts, solar energetic particles (SEPs) and galactic cosmic rays (GCRs), directly influences space systems. These systems rely on complex and fragile electronic devices, whose performance can be degraded because of the action of the radiation and its related phenomena: single-event effects (SEEs), displacement damages (DDs) and total ionizing dose (TID). This could cause failures to arise through various mechanisms, ranging from parametric drift failures, such as leakage current and threshold voltage, among others, to destructive effects, like single-event burnout (SEB) or single-event latch-up (SEL). These failures in electronics affect the system’s reliability and its performance, which could compromise the mission’s success. Considering this, the main objective of the SRPROTEC project is to develop and validate new composite materials with better shielding performance against space radiation to increase the radiation tolerance of microelectronic devices encapsulated with these materials. For this purpose, three composites will be synthesized using a liquid epoxy resin filled with silica as a matrix mixed in different proportions, with a high-Z filler. The presence of low-Z elements from the high hydrogen content in the polymer and the presence of high-Z fillers are expected to produce a material with good radiation shielding properties. The developed materials will be exhaustively characterized, subjecting the three composites and control samples to rheological outgassing; gamma radiation shielding; and thermal, electrical, thermomechanical and moisture absorption, among other tests. Finally, the composite with the best performance will be selected and subjected to degradation tests (thermal cycling in vacuum, thermal cycling, thermal shock and relative humidity tests) to determine its suitability for space packaging applications. Full article

This study aims to evaluate the effects of total ionizing dose (TID) radiation on the performance of n−MOSFET current mirrors. We propose an ovel experimental approach to analyze the interaction between charge trapping in the MOSFET gate oxide and the resulting current mirror degradation by subjecting devices to TID doses from 50 krad(Si) to 300 krad(Si) using a 60Co gamma source Experimental data show that threshold voltage shifts by up to 1.31 V and transconductance increases by 27%. This degradation leads to this a reduction of more than 10% in current mirror output accuracy occurs at the highest dose. These quantitative criteria establish a clear benchmark for assessing the impact of TID on current mirror performance. These effects are attributed to positive charge trapping in the gate oxide and at the Si–SiO₂ interface induced by ionizing radiation. This study focuses exclusively on radiation effects; electrical stress phenomena such as over−voltage or electrostatic discharge (ESD) are not addressed. The results highlight the critical importance of accounting for TID effects when designing high−performance n−MOSFET current mirrors for radiation−hardened applications. Full article

Combined radiation exposures—pairings of ionizing and non-ionizing radiation—are increasingly relevant in medical, spaceflight, and environmental contexts. This systematic review evaluates their radiobiological effects and therapeutic applications, focusing on synergistic interactions and underlying biological mechanisms. A comprehensive search of PubMed, Google Scholar, Semantic Scholar, bioRxiv, and Europe PMC identified studies published from the 1960s through 2025. Eligible studies assessed biological responses to different radiation types applied either simultaneously or within 24 h, with minor exceptions. A total of 172 studies were included and categorized into radiobiological, therapeutic, and space radiation domains. Due to the predominance of mechanistic research, no formal risk-of-bias tool was applied; methodological limitations were assessed qualitatively. Findings were synthesized narratively by radiation type and domain. Synergistic and additive effects were frequently observed, with responses influenced by dose, sequence, radiation type, and DNA repair dynamics. Therapeutic combinations often enhanced efficacy, while space radiation studies revealed multifaceted biological damage. This review provides a consolidated reference for advancing research and applications involving combined radiation exposures, emphasizing the need for mechanistic insight and standardized protocols in therapy, radiation protection, and spaceflight. This study was funded by project 21GRD02 BIOSPHERE (European Partnership on Metrology, Horizon Europe) and reported per PRISMA 2020 guidelines; no protocol was registered. Full article

Background: Irradiation-induced injury is a common fallout of radiological/nuclear accidents or therapeutic exposures to high doses of radiation at high dose rates. Currently, there are no prophylactic drugs available to mitigate radiation injury as a result of exposure to lethal doses of ionizing radiation. Gamma-tocotrienol (GT3) of vitamin E is a promising radioprotector under advanced development which has been tested for efficacy in both murine and nonhuman primate (NHP) models. Previously, we have demonstrated that GT3 has radioprotective efficacy in intestinal epithelial and crypt cells, and restores transcriptomic changes in NHPs with a supralethal dose of 12 Gy total-body irradiation (TBI). Methods: In this study, we evaluated the effect of 12 Gy partial-body irradiation (PBI) or TBI on metabolomic changes in serum samples and the extent to which GT3 was able to modulate these irradiation-induced changes. A total of 32 nonhuman primates were used for this study, and blood sample were collected 3 days (d) prior to irradiation, and 4 h, 8 h, 12 h, 1 d, 2 d, and 6 d post-irradiation. Results: Our results demonstrate that exposure to a supralethal dose of radiation induces a complex range of metabolomic shifts with similar degrees of dysregulation in both partial- and total-body irradiated animals. The C21-steroid hormone biosynthesis and metabolism pathway was significantly dysregulated in both PBI and TBI groups, with minimal protection afforded by GT3 administration. Conclusions: GT3 offered a differential response in terms of protected metabolites and pathways in either group that was most effective at the early post-irradiation time points. Full article

In this paper, a systematic study on performance degradation of a 0.18 μm BCD-process DCAP (Direct connection to the output CAPacitor) power chip under a total-dose radiation environment is carried out. The effects of total-dose radiation on the electrical characteristics of an MOS device are analyzed through device-level simulation. Based on the simulation results, a total-dose fault injection model is established and applied to a circuit-level simulation of the DCAP power chip. Our simulation modeling and analysis results show that total-dose radiation degrades output voltage accuracy and switching frequency, to which the bandgap reference circuit is identified as the most sensitive module. The findings presented in this paper provide theoretical support for total-dose radiation hardening designs for the DCAP power chip. Full article

Background/Objectives: Non-enhanced computed tomography of the kidneys, ureters and bladder (NECT KUB) is the initial imaging modality for suspected nephroureterolithiasis. However, for alternative diagnoses, NECT may not be the ideal technique. Our institution changed the protocol for this cohort from NECT to intravenous contrast-enhanced CT (CECT) KUB. We aimed to retrospectively compare the rate of alternative diagnosis seen and the rates of calculus detection in CECT versus NECT KUB as a means of assessing performance. Our secondary aim was to compare the radiation dose between CECT and NECT KUB. Methods: Patients referred from the emergency department with suspected nephroureterolithiasis who underwent NECT and CECT KUB over two years were included. Key performance metrics included calculus detection rate, alternative findings, and negative studies. The metrics were compared between genders and age groups. Categorical variables were analysed using Chi-squared or Fisher’s Exact Test and continuous with T-testing. Results: A total of 423 patients had CT KUB imaging (209 NECT, 214 CECT). The incidence of alternative findings in the NECT group was 23% and 40% in CECT (p < 0.001). There were 48 findings (13 major, 11 moderate and 24 minor) in NECT studies and 85 findings (23 major, 43 moderate and 19 minor) in CECT (p < 0.001). Major diagnoses ranged from acute emergencies to more indolent findings, including suspicious nodules/masses. The calculus detection rate (NECT 56%, CECT 54%, p = 0.643) and negative studies (NECT 28%, CECT 22%, p = 0.168) did not significantly differ between protocols. CECT had a mean effective dose of 8.71 ± 2.58 mSv representing 2.4 times the exposure of NECT (p < 0.001). Conclusions: CECT is associated with a greater alternative diagnosis rate with similar calculus detection rates compared to NECT KUB, suggesting superior performance. However, CECT exposes patients to significantly greater levels of ionizing radiation. Full article

Pre-metastatic niche (PMN) formation is a critical step in metastatic progression. However, the biological effects of subtherapeutic doses of ionizing radiation (SDIRs) following radiotherapy on this process remain unclear. Using a 4T1 breast cancer mouse model, we investigated the effects of SDIRs (3 × 0.3 Gy) on lung PMN development and metastasis upon SDIR exposure on days 8–10 post-tumor injection, followed by mastectomy and analyzed on day 24. SDIRs significantly increased the total metastatic volume (TMV) in lungs, suggesting an accelerated PMN formation. Mechanistically, the SDIR acted as an early catalyst for niche priming, upregulating Bv8 expression, enhancing neutrophil recruitment, and increasing MMP9, S100A8, and Il6 production in the PMN by day 11. Moreover, SDIR drives metastasis through distinct mechanisms. Proteomic analysis revealed SDIR-driven metabolic reprogramming, with a shift away from fatty acid metabolism toward glycolysis and lipid accumulation within the PMN. This shift contributes to extracellular matrix (ECM) remodeling, immune modulation, and the upregulation of adhesion-related pathways, shaping a microenvironment that accelerates metastatic outgrowth. By reprogramming the pre-metastatic lung, the SDIR highlights the need to integrate organ-specific radiation exposure into metastasis models. Metabolic and immune-stromal pathways emerge as potential therapeutic targets, underscoring the importance of refining radiotherapy strategies to mitigate unintended pro-metastatic effects. Full article

This study systematically investigates the mechanism by which total ionizing dose (TID) affects the lifetime degradation of NMOS devices induced by hot-carrier injection (HCI). Experiments involved Cobalt-60 (Co-60) gamma-ray irradiation to a cumulative dose of 500 krad (Si), followed by 168 h annealing at 100 °C to simulate long-term stability. However, under HCI stress conditions (V_D = 2.7 V, V_G = 1.8 V), irradiated devices show a 6.93% increase in threshold voltage shift (ΔV_th) compared to non-irradiated counterparts. According to the IEC 62416 standard, the lifetime degradation of irradiated devices induced by HCI stress is only 65% of that of non-irradiated devices. Conversely, when the saturation drain current (I_Dsat) degrades by 10%, the lifetime doubles compared to non-irradiated counterparts. Mechanistic analysis demonstrates that partial neutralization of E’ center positive charges at the gate oxide interface by hot electrons weakens the electric field shielding effect, accelerating ΔV_th drift, while interface trap charges contribute minimally to degradation due to annealing-induced self-healing. The saturation drain current shift degradation primarily correlates with electron mobility variations. This work elucidates the multi-physics mechanisms through which TID impacts device reliability and provides critical insights for radiation-hardened design optimization. Full article

Purpose: To evaluate the variability of oncogenic risk related to radiation exposure in patients frequently exposed to ionizing radiation for diagnostic purposes, specifically ICU patients, according to different risk models, including the BEIR VII, ICRP 103, and US EPA models. Methods: This was an IRB-approved observational retrospective study. A total of 71 patients (58 male, 13 female; median age, 66 years; interquartile range [IQR], 65–71 years) admitted to the ICU who underwent X-ray examinations between 1 October 2021 and 28 February 2023 were included. For each patient, the cumulative effective dose during a single hospital admission was calculated. Lifetime attributable risk (LAR) was estimated based on the BEIR VII, ICRP 103, and US EPA risk models to calculate additional oncogenic risk related to radiation exposure. The Friedman test for repeated-measures analysis of variance was used to compare risk values between different models. The intraclass correlation coefficient (ICC) was used to assess the consistency of risk values between different models. Results: Different organ, leukemia, and all-cancer risk values estimated according to different oncogenic risk models were significantly different, but the intraclass correlation coefficient revealed a good (>0.75) or even excellent (>0.9) agreement between different risk models. The ICRP 103 model estimated a lower all-cancer (median 69.05 [IQR 30.35–195.37]) and leukemia risk (8.22 [3.02–27.93]) compared to the US EPA (all-cancer: 139.68 [50.51–416.16]; leukemia: 23.34 [3.47–64.37]) and BEIR VII (all-cancer: 162.08 [70.6–371.40]; leukemia: 24.66 [12.9–58.8]) models. Conclusions: Cancer risk values were significantly different between risk models, though inter-model agreement in the consistency of risk values was found to be good, or even excellent. Full article

Hypericum perforatum L. (St John’s wort) has been widely studied and used for antidepressant treatment, as well as, rarely, featuring in studies on its chemical composition for Parkinson’s disease (PD) treatment. Five new nor-prenylated acylphloroglucinols with a cyclohexanone core, norperforatums A–E (1–5), together with four known analogs [(2R,3R,4S,6R)-3-methyl-4,6-di(3-methyl-2-butenyl)-2-(2-methyl-1-oxopropyl)-3-(4-methyl-3-pentenyl)cyclohexanone (6), hyperscabrin B (7), (2R,3R,4S,6R)-6-methoxycarbonyl-3-methyl-4,6-di(3-methyl-2-butenyl)-2-(2-methyl-1-oxopropyl)-3-(4-methyl-3-pentenyl)cyclohexanone (8), and hyperscabin K (9)], were isolated from the aerial parts of H. perforatum. The structures and absolute configurations of the new compounds were characterized by multiple spectroscopic means, including nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), ultraviolet visible absorption spectroscopy (UV), infrared spectroscopy (IR), calculated electronic circular dichroism (ECD) data, and X-ray signal crystal diffraction. In addition, the efficacy of these isolations was evaluated against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD in zebrafish larvae. Compound 9 had the best therapeutic effect, by significantly increasing the total distance traveled and the mean speed of movement in PD dyskinesia zebrafish larvae. Moreover, it enhanced superoxide dismutase (SOD) activity and inhibited reactive oxygen species (ROS) production in a dose-dependent manner. These results suggest that compound 9 may have ameliorative effects on PD symptoms by inhibiting oxidative stress. This study provides new insights into the treatment of H. perforatum for PD. Full article

A comparative study on the synergistic effect of the total ionizing dose and neutron single event effect on a SiC MOSFET and Si MOSFET was performed based on the ⁶⁰Co γ source and the high-pressure multiplier 14 MeV neutron source at the China Institute of Atomic Energy. First, a γ-ray total ionizing dose experiment was performed on these two devices, and the differences in the total ionizing dose damage of the SiC and Si MOSFETs were analyzed. Then, neutron single event effect experiments were performed to investigate the effects of different doses on the single event effect for the devices. The results indicate that the unhardened SiC MOSFET has stronger resistance to the total ionizing dose compared with hardened Si MOSFET. During the 14 MeV neutron irradiation experiment, no single event burnout was observed in either device, but single event transients were observed. Even though the hardened Si MOSFETs are capable of suppressing single event transient currents at a higher drain bias, the trapped charge concentration of SiC MOSFETs due to irradiation is smaller than that of Si MOSFETs, which improves their resistance to the total ionizing dose and makes them less affected by the synergistic effect of the total ionizing dose and neutron single event effects. The research results can provide some guidelines for the radiation hardening technology of power devices used in aerospace and nuclear industries. Full article

Hybrid ceramics exhibit low wear on antagonist tooth enamel, which may positively impact the oral rehabilitation of head-and-neck irradiated patients who experience alterations in tooth microstructure and wear resistance. This study aimed to evaluate the wear resistance of hybrid ceramics after gamma radiation exposure in contact with irradiated tooth enamel, as well as their mechanical and chemical properties. Notably, no previous studies focusing on the effects of radiation on hybrid ceramics were found in the literature. Vita Enamic discs and tooth fragments were subjected to daily doses of 2 Gy, totaling 0, 20, 40, 50, 60, and 70 Gy. The wear resistance of hybrid ceramics and a ceramic enamel analog (steatite) was tested against tooth enamel using a chewing simulation machine. Hybrid ceramic specimens underwent hardness, biaxial flexural strength, roughness, and FT-IR analyses. The data were analyzed using an ANOVA and Tukey’s test (α = 0.05). Enamic exposed to 60 and 70 Gy exhibited higher wear and caused less tooth enamel loss compared to steatite. The mechanical and chemical properties remained unchanged after irradiation. The roughness decreased across all groups after a chewing simulation but was not affected by irradiation. In conclusion, ionizing radiation did not alter the material’s properties but increased its wear. Full article