Search Results (674)

The biological effects of radiofrequency electromagnetic fields (RF-EMFs) remain an unresolved scientific issue with important societal relevance, particularly in the context of the global deployment of fifth-generation (5G) wireless technologies. The skin is continuously exposed to both RF-EMFs and ultraviolet (UV) radiation, a well-established inducer of oxidative stress and DNA damage, making it a relevant model for assessing combined environmental exposures. In this study, we investigated whether post-exposure to 5G RF-EMFs (3.5 and 28 GHz) modulates ultraviolet A (UVA)-induced genotoxic stress in human keratinocytes (HaCaT) and murine melanoma (B16) cells. Post-UV RF-EMF exposure significantly reduced DNA damage markers, including phosphorylated histone H2AX (γH2AX) foci formation (by approximately 30–50%) and comet tail moments (by 60–80%), and suppressed intracellular reactive oxygen species (ROS) accumulation (by 56–93%). These effects were accompanied by selective attenuation of p38 mitogen-activated protein kinase (MAPK) phosphorylation (reduced by 55–85%). The magnitude of molecular protection was comparable to that observed with N-acetylcysteine treatment or pharmacological inhibition of p38 MAPK. In contrast, RF-EMF exposure did not reverse UV-induced reductions in cell viability or alterations in cell cycle distribution, indicating that its protective effects are confined to early molecular stress-response pathways rather than downstream survival outcomes. Together, these findings demonstrate that 5G RF-EMFs can facilitate recovery from UVA-induced molecular damage via redox-sensitive and p38-dependent mechanisms, providing mechanistic insight into the interaction between modern telecommunication frequencies and UV-induced skin stress. Full article

The para-positronium system $\left({}^{1}S_{0}Ps\right)$ is described by means of specially constructed coherent states (CSs) in the Klauder–Perelomov sense. It is analyzed from the physical point of view and from the geometry underlying the relevant symmetry group establishing the dynamics of the processes. In this new theoretical context, the possibility of a gamma-ray laser emission is investigated within a QFT context, showing explicitly that, in addition to the oscillator solution based only on a Bogoliubov approximation for the condensate, there is a second phase or “squeezed” stage by which physical features beyond the classical ones appear. Explicitly, while the generated photons are in the active medium (e.g., Ps-BEC), the evolution is described by a Heisenberg–Weyl coherent state with displacement operators dependent on the interaction time, which is related to the condensate shape. After the interaction time has elapsed, we explicitly demonstrate that the displacement operator of the ${}^{1}S_{0}Ps$ is transformed into a squeezed operator of the photonic fields modulated by the matrix element of the Positronium decay ${\mathcal{M}}_{{}^{1}S_{0}Ps}\to 2\gamma$. We also show that this squeezed operator (belonging to the Metaplectic group) generates a non-classical radiation state spanning only even (s = 1/4) levels in the number of photons. The implications in astrophysical systems of interest, considering gamma-ray coherent emission and the possibility of an ${}^{1}S_{0}Ps-BEC$ in the context of pulsars, blazars, and quasars, are briefly discussed. Full article

Lightweight, lead-free polymer–mineral composites have attracted increasing interest as radiation-attenuating materials for applications where reduced mass and environmental compatibility are required. In this work, the $\gamma$-ray attenuation behavior of poly(ether ether ketone) (PEEK) reinforced with natural palygorskite and pumice was evaluated at filler concentrations of 10–40 wt%. Photon interaction parameters, including the linear attenuation coefficient ($\mu$), half-value layer (HVL), mean free path ($\lambda$), and effective atomic number ($Z_{\mathrm{eff}}$), were computed over the energy range 15 keV–15 MeV using the Phy-X/PSD platform and validated through full Geant4 Monte Carlo transmission simulations. At 15 keV, $\mu$ increased from $1.46{\mathrm{cm}}^{-1}$ for pure PEEK to $4.21{\mathrm{cm}}^{-1}$ and $8.499{\mathrm{cm}}^{-1}$ for the 40 wt% palygorskite- and pumice-filled composites, respectively, reducing the HVL from 0.69 cm to 0.24 cm and 0.11 cm. The corresponding $Z_{\mathrm{eff}}$ values increased from 6.5 (pure PEEK) to 9.4 (40 wt% palygorskite) and 15.3 (40 wt% pumice), reflecting the influence of higher-Z oxide constituents in pumice. At higher photon energies, the attenuation curves converged as Compton scattering became dominant, although pumice-filled PEEK retained marginally higher $\mu$ and shorter $\lambda$ up to the MeV region. These findings demonstrate that natural mineral fillers can enhance the photon attenuation behavior of PEEK while retaining the known thermal stability and mechanical performance of the polymer matrix as reported in the literature, indicating their potential use as lightweight, secondary radiation-attenuating components in medical, industrial, and aerospace applications. Full article

Radiotherapy is an effective treatment for cancer; however, radioresistant cancer cells result in recurrence. Therefore, elucidating the mechanisms of radioresistance is urgently needed. Super-enhancers (SEs) are clusters of enhancers occupied by a high density of master transcription factors, mediators, and bromodomain protein BRD4. Recently, we reported that ΔNp63, an oncogenic transcription factor, promotes radioresistance in human head and neck squamous cell carcinoma (HNSCC) cells. As ΔNp63 establishes SEs in HNSCC cells, SEs may be involved in radioresistance. Here, we investigated the role of the SE component BRD4 in the radiation responses of HNSCC cells using a BRD4 degrader ARV-771 or BRD4 knockdown. First, Western blotting confirmed that ARV-771 decreased BRD4 protein expression. ARV-771 treatment resulted in reduced cell proliferation and enhanced apoptosis in irradiated HNSCC cells. Moreover, colony formation assays revealed that both ARV-771 and BRD4 knockdown enhanced the radiosensitivity of HNSCC cells, suggesting BRD4 contributes to the radioresistance of HNSCC cells. Furthermore, fluorescence immunostaining revealed distinct localization patterns of γH2AX, a marker of DNA double-strand breaks, compared with BRD4 and ΔNp63 in irradiated cells. Notably, ARV-771 and BRD4 knockdown decreased ΔNp63 and BRD4 protein expression, whereas ΔNp63 knockdown had minimal impact on BRD4 expression. Taken together, these findings suggest that BRD4-dependent maintenance of ΔNp63 expression may contribute, at least in part, to the regulation of radioresistance in HNSCC cells. Full article

Background. Acute radiation injury to the small-intestinal mucosa and the hematopoietic system is a key determinant of early mortality after high-dose total-body irradiation. ε-Aminocaproic acid (EACA), a lysine analogue with antifibrinolytic properties, has been proposed as a potential radioprotective agent, but its effects on intestinal and hematologic injury remain insufficiently characterized. Methods. In this experimental study, 240 male Wistar rats were subjected to single-dose total-body γ-irradiation at 10.6 Gy and randomized into six groups: two non-irradiated controls (CG-1, CG-2), an irradiated control without treatment (CG-3), and three experimental groups receiving EACA (EG-1: 3 h before irradiation; EG-2: 3 h after irradiation; EG-3: both 3 h before and 3 h after irradiation). Pain behavior was assessed using the Rat Grimace Scale. Intestinal damage was evaluated by a modified Radiation Injury Intestinal Mucosal Damage Score (RIIMS_sum), villus and crypt morphometry, and qualitative histology of the ileum. Hemoglobin, leukocytes, and platelets were measured serially, and 30-day survival was analyzed using Kaplan–Meier curves with log-rank tests. Results. Across all EACA regimens, the odds of being in a higher Rat Grimace Scale pain category were reduced compared with CG-3, with the strongest effect in EG-3 (OR 0.42; 95% CI 0.31–0.58). At 72 h after irradiation, the cumulative RIIMS score was lower in EACA-treated groups by approximately 17–36% versus CG-3, with the lowest injury in EG-3 (18.5 vs. 29.0 points). EACA attenuated shortening and blunting of villi, preserved crypt architecture, and mitigated anemia, leukopenia, and thrombocytopenia. Thirty-day survival was 20% in CG-3 and 60%, 65%, and 80% in EG-1, EG-2, and EG-3, respectively (all p < 0.05 vs. CG-3). Conclusions. ε-Aminocaproic acid exerts a pronounced, timing-dependent radioprotective effect in a rat model of acute total-body γ-irradiation, concurrently reducing the severity of radiation enteritis, hematologic toxicity, and early mortality. These findings support further investigation of EACA as a candidate adjunct in the prevention of acute radiation injury. Full article

Ionizing radiation remains the primary approach for treating brain cancer and is frequently used in combination with chemotherapy. However, when it comes to gliomas, the effective delivery of therapeutic agents is hindered by the limited permeability of the blood–brain barrier (BBB). Consequently, selecting the most suitable and least harmful type of ionizing radiation is essential, given its potential side effects on healthy cells within the tumor microenvironment. In this study, we explored the impact of X-ray exposure on two in vitro BBB endothelial cell models—murine and human. Post-irradiation, we evaluated cell viability, clonogenic capacity, cell cycle progression, reactive oxygen species (ROS) levels, formation of micronuclei and γ-H2AX foci, as well as alterations in cytoskeletal organization, cell migration, and intracellular calcium dynamics. The results demonstrate notable differences between the two endothelial cell lines, suggesting the human cell line is more sensitive to X-rays. In conclusion, our study provides valuable insights into the brain microvascular endothelial cells’ response to radiation, laying the groundwork for strategies to protect healthy brain tissue. Full article

Protons are conventionally regarded as a low-linear energy transfer (low-LET) radiation modality with a relative biological effectiveness (RBE) of 1.1, suggesting direct mechanistic similarity to X-rays in the underpinning biological effects. However, exposure to spread-out Bragg peak (SOBP) protons reveals instructive deviations from this assumption. Indeed, proton beams have a maximum LET of ~5 keV/µm but display reduced reliance on classical non-homologous end joining (c-NHEJ) as well as an increased dependence on homologous recombination (HR) and alternative end joining (alt-EJ). These features are well described in cells exposed to high-LET radiation and typically manifest between 100 and 150 keV/µm. We hypothesized that this apparent discrepancy reflects biological consequences of proton-beam properties that remain uncharacterized. In the present study, we outline exploratory experiments aiming at uncovering such mechanisms. We begin by investigating for both entrance and SOBP protons the dose-dependent engagement of HR we recently showed for X-rays. Consistent with our previous findings with X-rays, HR engagement after exposure to both types of proton beams declined with dose, from ~80% at 0.2 Gy to less than 20% at higher doses. RAD51/γH2AX foci ratios, reflecting HR engagement, were modestly higher following proton irradiation, in line with increased HR utilization. G₂-checkpoint activation, previously linked to HR, was also stronger after exposure to protons, as was DNA end resection. Moreover, the formation of structural chromosomal abnormalities (SCAs) was higher for SOBP than entrance protons and X-rays. Collectively, our results suggest quasi-high-LET characteristics for proton beams and raise the question as to the physical proton properties that underpin them. We discuss that the commonly employed definition of LET may be insufficient for this purpose. Full article

The reliability of rubber materials in nuclear sealing applications depends on their resistance to ionizing radiation. To explicitly reveal the differences in radiation damage mechanisms among rubbers with varying molecular structures, this study investigated four typical elastomers—natural rubber (NR), butyl rubber (IIR), chloroprene rubber (CR), and nitrile rubber (NBR)—under ⁶⁰Co γ-irradiation at cumulative doses of 1, 10, and 100 kGy. By coupling macroscopic physical testing (mechanical, permeability) with microstructural characterization (FT-IR, DSC, crosslink density), a correlation between material structure and irradiation behavior was established. The results indicate that main-chain saturation dictates the dominant degradation mechanism: unsaturated rubbers (NR, CR, NBR) are dominated by cross-linking, macroscopically manifested as increased hardness and reduced ductility; conversely, saturated rubber (IIR) is dominated by main-chain scission, leading to a paste-like transition at 100 kGy and a complete loss of mechanical load-bearing and barrier functions. Comparatively, NR exhibited optimal overall stability due to “clean” cross-linking without significant oxidation. The overall radiation resistance ranking within the 0–100 kGy range is NR > CR > NBR > IIR. This study clarifies the “structure-mechanism-property” evolution law, providing a critical theoretical basis for lifetime prediction and rational material selection of rubber components in nuclear environments. Full article

Currently, the use of scintillation crystals connected via optical fiber to a luminescence spectrometer (so-called fiber-optic dosimeters) offers a promising approach for real-time dosimetric measurements during brachytherapy treatments with γ-ray sources. This study aims to evaluate the applicability of fiber-optic dosimeters for in situ dose measurements during brachytherapy procedures, using Al₂O₃:C and Al₂O₃:C,Mg crystals, which have near-tissue density and effective atomic number (ρ = 3.99 g/cm³, Z_eff = 10.8), as well as heavy GAGG:Ce scintillation crystals (ρ = 6.63 g/cm³, Z_eff = 54.4). Radiation dose delivery was assessed through measurements of the resulting radioluminescence of the aforementioned scintillation crystals, connected via long optical fibers and recorded with highly sensitive, compact luminescence spectrometers. Measurements were performed in a dedicated phantom under clinical conditions at the Oncology Center in Bydgoszcz, Poland. The dosimeters were evaluated for in situ dose monitoring within the 0.5–8 Gy range during brachytherapy procedures using a ¹⁹²Ir (392 keV) source. The results showed a clear linear relationship between the delivered radiation dose and the scintillation output measured by the fiber-optic detector. The Gd₃Al_2.5Ga_2.5O₁₂:Ce crystal detector exhibited excellent linearity, while the Al₂O₃:C and Al₂O₃:C,Mg crystal detectors also showed a nearly linear dose–response relationship. Full article

In this work, we analyze the dynamical evolution of locally rotationally symmetric anisotropic cosmological models of Bianchi type I (flat curvature) and Bianchi type III (open curvature) within a noncommutative phase space framework characterized by a deformation parameter $\gamma$. Using a Hamiltonian formulation based on Schutz’s formalism for a perfect radiation fluid, we introduce noncommutative Poisson brackets that allow for geometric corrections to commutative dynamics. The resulting equations are solved numerically, which allows for the study of the impact of $\gamma$ and the energy density C on the expansion of the universe and the evolution of anisotropy. The results show that $\gamma <0$ improves expansion and favors isotropization, while $\gamma >0$ tends to slow expansion and preserve residual anisotropy, especially in the open curvature model. It is estimated that the influence of noncommutativity was significant during the early stages of the universe, decreasing toward the present time, suggesting that this approach could serve as an effective alternative to the cosmological constant in describing the evolution of the early universe. Full article

Computed tomography (CT) is a major source of low-dose ionizing radiation exposure in medical imaging. Risk assessment at this dose level is difficult and relies on the hypothetical linear no-threshold model. To address the response to such low doses in patients undergoing CT scans, we examined radiation-induced alterations at the transcriptomic and DNA damage levels in peripheral blood cells. Peripheral whole blood of 60 patients was collected before and after CT. Post-CT samples were obtained 4–6 h after scan (n = 28, in vivo incubation) or alternatively immediately after the CT scan, followed by ex vivo incubation (n = 32). The gene expression of known radiation-responsive genes (n = 9) was quantified using qRT-PCR. DNA double-strand breaks (DSB) were assessed in 12 patients through microscopic γ-H2AX + 53BP1 DSB focus staining. The mean dose–length product (DLP) across all scans was 561.9 ± 384.6 mGy·cm. Significant differences in the median differential gene expression (DGE) were detected between in vivo and ex vivo incubation conditions, implicating that ex vivo incubation masked the true effect in low-dose settings. The median DGE of in vivo-incubated samples showed a significant upregulation of EDA2R, MIR34AHG, PHLDA3, DDB2, FDXR, and AEN (p ranging from <0.001 to 0.041). In vivo, we observed a linear dose-dependent upregulation for several genes and an explained variance of 0.66 and 0.56 for AEN and FDXR, respectively. DSB focus analysis revealed a slight, non-significant increase in the average DSB damage post-exposure, at a mean DLP of 321.0 mGy·cm. Our findings demonstrate that transcriptional biomarkers are sensitive indicators of low-dose radiation exposure in medical imaging and could prove themselves as clinically applicable biodosimetry tools. Furthermore, the results underscore the need for dose optimization. Full article

Exposure to ionizing and non-ionizing radiation from environmental and clinical settings can significantly threaten genomic stability, especially when combined. This ex vivo study investigates the potential combined effects of gamma radiation and ultraviolet B (UVB) exposure on human peripheral blood mononuclear cells (PBMCs) from healthy donors by exposing whole blood and isolated PBMCs to 1 Gy of gamma rays, to an absolute dose of approximately 100 J/m² of UVB, or to their combination. Combined exposure resulted in significantly elevated γH2AX foci formation and chromosomal aberrations relative to individual stressors, with the most pronounced effects observed in isolated PBMCs. Notably, lymphocytes from some donors failed to proliferate after UVB or co-exposure. Based on our results, a predictive biophysical model derived from dicentric yield was developed to estimate the gamma-ray equivalent dose from co-exposure, indicating up to ~9% increase in lifetime cancer risk. Although this proof-of-concept study included only a small number of donors and focused on two endpoints (γH2AX and dicentric assays), it provides a controlled framework for investigating mechanisms of radiation-induced genomic instability. The results emphasize the importance of accounting for mixed radiation exposures in genotoxic risk assessment and radiation protection. Full article

The rapid development of deep-space exploration and crewed missions makes efficient, lightweight, and low–secondary-radiation γ-ray protection in complex cosmic fields a critical materials challenge. Current studies still struggle to simultaneously balance attenuation efficiency, areal density and thickness, flexibility, and shielding against secondary γ rays. Compared with existing reviews that mainly focus on single matrices (especially polymers) or medical lead-based protection, this work targets γ-ray shielding under deep-space and mixed radiation environments, emphasizing multiscale structural designs (multilayer/gradient architectures, micro/nanofiller synergy, and fiber networks) for suppressing secondary γ-rays and outlining composition–structure–morphology–coupled strategies for flexible, wearable, lead-free shields. Recycling and sustainability remain key bottlenecks for practical deployment. Accordingly, this review also summarizes representative Monte Carlo simulation tools and their integration with experiments, and proposes directions for element selection, structural design, and green manufacturing to build design rules and a scale-up roadmap for next-generation lead-free γ-shielding wearables. Full article

Lightweight and lead-free radiation shields are increasingly developed to overcome the toxicity and handling challenges associated with conventional heavy-metal-based materials. In this study, the $\gamma$-ray attenuation behavior of polymer–zeolite composites was examined by reinforcing high-density polyethylene (HDPE) and polylactic acid (PLA) with natural clinoptilolite zeolite at concentrations of 10–40 wt%. Photon-interaction parameters, including the linear attenuation coefficient ($\mu$), half-value layer (HVL), mean free path ($\lambda$), and effective atomic number ($Z_{\mathrm{eff}}$), were evaluated over 15 keV–15 MeV using the Phy-X/PSD platform. Zeolite incorporation consistently enhanced photon attenuation, particularly at low energies dominated by the photoelectric effect. At 15 keV, the HVL decreased from 0.60 cm to 0.08 cm for HDPE and from 0.043 cm to 0.033 cm for PLA as the zeolite loading increased to 40 wt%. Correspondingly, $Z_{\mathrm{eff}}$ increased from 2.7 to 4.3 for HDPE and from 6.5 to 11.6 for PLA, while $\mu$ reached approximately 41 cm⁻¹ and 56 cm⁻¹ at 15 keV for the respective 40 wt% composites. Beyond about 1 MeV, differences between compositions became minimal as Compton scattering dominated. PLA–zeolite composites exhibited higher $\mu$ and lower HVL than HDPE–zeolite, whereas HDPE maintained an advantage in mixed-field environments owing to its hydrogen-rich matrix. The results confirm that zeolite-reinforced polymers are safe, low-cost, and lightweight materials suitable for radiation shielding in medical, nuclear, and aerospace applications. Full article

Hybrid halide perovskites are promising materials for optoelectronics and space applications due to their excellent light absorption, high efficiency, and light weight. However, their stability under radiation exposure remains a key challenge, especially in space environments, where high-energy particles can cause significant damage. Here, we present the effects of primary and secondary radiation on perovskite materials, using Monte-Carlo simulations with the GEANT4 toolkit. The interactions of protons, electrons, neutrons, and γ-rays with APbI3 (A = Ma, FA, Cs) perovskites under space-relevant conditions typical for low Earth orbit (LEO) were studied. The results show that different perovskite compositions respond uniquely to radiation: CsPbI₃ generates higher-energy secondary positrons, neutrons, and protons, while MAPbI₃ produces more secondary electrons under proton irradiation. Mixed-cation perovskites exhibit narrower energy distributions for secondary γ-rays, indicating material-dependent differences in radiation tolerance. These findings suggest the potential role of secondary particle generation in perovskite degradation, based on our simulations, and they emphasize the need for comprehensive modeling to improve the radiation resistance of perovskite-based technologies for space applications. Future studies should consider contributions from encapsulating materials in device structures. Full article