Search Results (192)

In this study, the neutron and gamma radiation-shielding properties of serpentinites from the Guleman ophiolite complex were investigated, and results were evaluated in comparison with rare earth element (REE) content. The linear and mass attenuation coefficients (LAC and MAC), half-value layer (HVL), mean free path (MFP), and effective atomic numbers (Z_eff) of serpentinite samples were experimentally measured in the energy range of 80.99–383.85 keV. Theoretical MAC values were calculated. Additionally, fast neutron removal cross-sections, as well as thermal and fast neutron macroscopic cross-sections, were theoretically determined. The absorbed equivalent dose rates of serpentinite samples were also measured. The radiation protection efficiency (RPE) for gamma rays and neutrons were determined. It was observed that the presence of rare earth elements within serpentinite structure has a significant impact on thermal neutron cross-sections, while crystalline water content (LOI) plays an influential role in fast neutron cross-sections. Moreover, it has been observed that the concentration of gadolinium exerts a more substantial influence on the macroscopic cross-sections of thermal neutrons than on those of fast neutrons. The research results reveal the mineralogical, geochemical, morphological and radiation-shielding properties of serpentinite rocks contribute significantly to new visions for the use of this naturally occurring rock as a geological repository for nuclear waste or as a wall-covering material in radiotherapy centers and nuclear facilities instead of concrete. Full article

The widespread presence of antibiotics in aquatic environments poses significant ecological and public health risks due to their persistence, antimicrobial activity, and contribution to resistance gene proliferation. This review systematically evaluated the advancements in antibiotic degradation using ionizing radiation (γ-rays and electron beam) from laboratory studies to practical applications. By using keywords such as “antibiotic degradation” and “ionizing irradiation OR gamma radiation OR electron beam,” 328 publications were retrieved from Web of Science, with China contributing 33% of the literature, and a number of global representative studies were selected for in-depth discussion. The analysis encompassed mechanistic insights into oxidative (•OH) and reductive (e_aq⁻) pathways, degradation kinetics influenced by absorbed dose (1–10 kGy), initial antibiotic concentration, pH, and matrix complexity. The results demonstrated ≥90% degradation efficiency for major antibiotic classes (macrolides, β-lactams, quinolones, tetracyclines, and sulfonamides), though mineralization remains suboptimal (<50% TOC removal). Synergistic integration with peroxymonosulfate (PMS), H₂O₂, or O₃ enhances mineralization rates. This review revealed that ionizing radiation is a chemical-free, compatible, and highly efficient technology with effective antibiotic degradation potential. However, it still faces several challenges in practical applications, including incomplete mineralization, matrix complexity in real wastewater, and operating costs. Further improvements and optimization, such as hybrid system development (e.g., coupling electron beam with other conventional technologies, such as flocculation, membrane separation, anaerobic digestion, etc.), catalytic enhancement, and life-cycle assessments of this emerging technology would be helpful for promoting its practical environmental application. Full article

Background/Objectives: This systematic review and meta-analysis evaluated the effectiveness and the safety of transarterial radioembolization using Holmium-166 microspheres (Ho-166-TARE) for the treatment of primary and secondary liver tumors. The aim of the study was to offer a detailed analysis of clinical outcomes and the potential benefits of this innovative therapy. Methods: The study was conducted according to the PRISMA 2020 guidelines. The systematic search was performed in five databases in November 2023 and updated in June 2024. All 16 eligible studies were original research that evaluated Ho-166-TARE. The endpoints analyzed were disease control rate (DCR), overall survival (OS), progression-free survival (PFS), clinical and laboratory adverse events, healthy-liver- and tumor-liver-absorbed doses. The risk of bias was assessed using the MINORS checklist. Results: The pooled overall disease control rate (DCR) was 72% (95% CI, 46–89%); by mRECIST, it was 93% (95% CI, 71–99%); and by RECIST 1.1, it was 54% (95% CI, 22–83%) at 3-month follow-up. Overall survival (OS) at 3, 6, 12, and 30 months was 98%, 89%, 74%, and 39%, respectively. Severe clinical adverse events were minimal, although some patients showed elevated GGT levels and lymphocytopenia. Tumor-absorbed doses were nearly three times higher than those in healthy liver tissue. Conclusions: These findings suggest that Ho-166-TARE is a safe and effective locoregional treatment option for liver tumors, especially in cases where systemic therapy alone is insufficient or surgical resection is not feasible. Further studies are needed to investigate tumor-specific response, optimize dosimetry strategies, and establish standardized protocols for long-term outcome assessment. Full article

This study investigated the spatial distribution and radiological risks of naturally occurring radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K) in 37 soil samples from Zacatecas, located in north-central Mexico, using high-resolution gamma spectrometry. Results revealed ⁴⁰K concentrations (mean: 736.81 Bq kg⁻¹), nearly double the global average, while ²²⁶Ra (29.96 Bq kg⁻¹) and ²³²Th (29.72 Bq kg⁻¹) aligned with worldwide norms. Geoaccumulation indices identified moderate ⁴⁰K accumulation at 22 sites, with El Capulín classified as moderately contaminated (I_geo = 1.07). Radiological risk indices showed absorbed dose rates (62.52 nGy h⁻¹) and excess lifetime cancer risk (0.330 × 10⁻³) exceeding global thresholds by 4% and 14%, respectively. Multivariate analyses demonstrated strong Spearman correlations (ρ = 0.75–1.00) among risk indices, while spatial interpolation identified southern/western regions as high-risk zones. These findings emphasize the necessity of integrating spatial analysis with multivariate statistical techniques in environmental radioprotection frameworks. While most of the study area complies with international safety standards, the identified zones exceeding dose thresholds warrant prioritized management to mitigate potential cumulative health risks. Full article

Catalase serves as a crucial component of the antioxidant defense system by catalyzing the decomposition of hydrogen peroxide into water and molecular oxygen. This study investigated the effects of 1 MeV accelerated electron irradiation on catalase activity in model solutions at doses of 100 Gy and 1000 Gy. Enzyme activity was assessed using two complementary methods: spectrophotometric analysis and the oxygen bubble method. The experimental results demonstrated dose-dependent inhibition of catalase activity, indicating that substantial radiation-induced structural modifications may occur in the enzyme molecule as a result of irradiation. To understand the relationship between the irradiation dose and the catalase inhibition, calibration curves plotting the dependencies of hydrogen peroxide decomposition rate and the delayed appearance of oxygen bubbles after adding hydrogen peroxide to catalase saline solution on the catalase concentration showed a 1.5-fold reduction in catalase activity at 100 Gy and a 40-fold decrease at 1000 Gy. Based on these findings, we propose a novel biodosimetry approach utilizing the oxygen bubble formation delay time as an express assessment tool for detecting high radiation doses absorbed by biological objects, for example, food products. The results obtained in the study have important implications for evaluating radiation effects on biological systems, in particular catalase-containing food products, offering potential applications in radiation safety monitoring and food quality control. Full article

This work reports the findings of an investigation aimed at assessing, for the first time, the natural and anthropogenic radioactivity content of marine sediments collected from selected areas of Sicily, Southern Italy. In particular, it focused on evaluating the average activity concentration of detected radionuclides and the radiological hazard for humans, above all considering the use of this material for nourishing actual eroded beaches. To this aim, the quantification of the average specific activity of ²²⁶Ra, ²³²Th, and ⁴⁰K natural and ¹³⁷Cs anthropogenic radioisotopes was addressed through the employment of High-Purity Germanium (HPGe) gamma-ray spectrometry. Furthermore, the absorbed gamma dose rate (D), the annual effective dose equivalent outdoor (AEDE_out), the external hazard index (H_ex), and the excess lifetime cancer risk (ELCR) were also calculated to evaluate the radiological hazard for humans related to external exposure to ionizing radiations. Furthermore, the average specific activity of ¹³⁷Cs was found to be less than the lowest detectable activity in all cases, excluding anthropogenic radioactive contamination of the investigated samples. Finally, Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA), i.e., multivariate statistics, were carried out by analyzing detected radioactivity and radiological characteristics to evaluate their relationship with the sampling locations. Full article

This study focused on identifying Th-, Nb-Ta-, Zr-, and REE-bearing minerals with a multivariate statistical approach in alkaline syenite to evaluate their radiological risks, at Nikeiba, Egypt. Through microchemical analyses, by utilizing electron probe microanalysis, horite, microlite, monazite, zircon, columbite, and fergusonite were shown to bear uranium and thorium. These minerals have played an important role in higher radioactive zones in the studied alkaline syenite. REE-minerals comprising bastnäsite, monazite, and fluorite and apatite are well recorded. The total rare earth elements (TREE₂O₃) reveal higher concentrations in bastnäsite than monazite, with averages 74.87 and 63.8 wt%. Ce is considered the most predominant LREE in the analyzed bastnäsite and monazite. The mean values of radionuclide activity concentrations of ²³⁸U, ²³²Th, and ⁴⁰K are 108 ± 20 Bq/kg, 107 ± 9 Bq/kg, and 1255 ± 166 Bq/kg, respectively. Radiological assessments revealed a radium equivalent activity of 357 Bq/kg, below global limits, but an air-absorbed dose rate (166 nGy/h) and annual effective doses (0.81 mSv/y indoors, 0.20 mSv/y outdoors) exceeding safe thresholds. Additionally, the excess lifetime cancer risk (ELCR) was calculated at 0.00071, surpassing the acceptable limit of 0.00029, making these rocks unsafe for construction use. Statistical analyses further underscored the relationships between radionuclide concentrations and associated risks, highlighting the necessity for continuous monitoring and mitigation. Full article

Utilizing gamma rays as an initiating agent, a simultaneous irradiation method was applied to graft acrylic acid and acrylamide onto corn straw that had been decrystallized using a NaOH/urea solution at a reduced temperature, aiming to fabricate superabsorbent polymer gel (SAPG) capable of absorbing significantly more water. The structural attributes of the corn straw, the decrystallized corn straw, and the SAPG were analyzed via Fourier transform infrared spectroscopy (FTIR), X-ray crystal powder diffraction (XRD), thermogravimetric analysis (TG), and scanning electron microscopy (SEM). To enhance the SAPG’s performance, optimization of various parameters was carried out, such as irradiation dose, dose rate, the ratio of monomer to corn straw, the proportion of acrylic acid (AA) to acrylamide (Am), and the degree of neutralization. The resulting SAPG exhibited distilled water absorption of 1033 g/g and 90 g/g in 0.9 wt.% NaCl solution, with a radiation dose of 5 kGy, a dose rate of 1.5 kGy/h, AA-to-AM mass ratio of 1.2, monomer-to-CS mass ratio of 7, and 90% AA neutralization. Full article

This paper presents a case study of the natural radioactivity level and radon exhalation in limestone and sandstone rocks from the archaeological park of Tindari, located in Sicily, southern Italy. These rocks were representative of natural stones utilised as building materials in the studied area. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were assessed using high purity germanium (HPGe) gamma-ray spectrometry. Subsequently, the absorbed gamma dose rate (D), annual effective dose equivalent (AEDE), activity concentration index (ACI), and alpha index (I_α) were quantified to evaluate potential radiological health risks associated with radiation exposure from the analysed rocks. Finally, E-PERM electret ion chamber measurements were conducted to accurately quantify the radon exhalation rate from the investigated samples. The results obtained in this case study provide a foundation for further research into the background radioactivity levels in natural stones employed as building materials. Full article

In traditional Chinese medicine, the root bark and leaves of Schima argentea are utilized to treat dysentery, parasitic infections, and digestive disorders. In this study, the n-butanol extract of S. argentea (NBA) exhibited potent antioxidant properties, protecting HaCaT cells from UVB-induced damage, and was abundant in phenolic and flavonoid compounds. Using UPLC-QTOF-MS analysis, several antioxidants within NBA were identified. Among these, 3,4-dihydroxybenzoic acid, (+)-catechin, and procyanidin B2 effectively reduced ROS levels after 1 h post-UVB treatment (225 mJ/cm²). Notably, all three compounds significantly decreased the phosphorylation of p38 and JNK in a dose-dependent manner. Additionally, the cell survival rate of these compounds was assessed after 12 h post-UVB treatment (225 mJ/cm²). Both 3,4-dihydroxybenzoic acid and (+)-catechin significantly prevented UVB-induced apoptosis in HaCaT cells, as evidenced by MTT, Hoechst, Calcein/PI staining, and flow cytometry analyses. Proteomic analysis revealed that 3,4-dihydroxybenzoic acid achieved photoprotection by downregulating c-Fos and Jun and modulating cell cycle proteins, while (+)-catechin promoted cell repair through the PI3K-Akt and Wnt signaling pathways. These results demonstrated that both compounds can directly absorb UVB, scavenge ROS, and provide cell photoprotection by modulating multiple signaling pathways. The n-butanol extract of S. argentea holds promising potential for future medical applications. Full article

Phytoremediation stands at the forefront of modern environmental science, offering an innovative and cost-effective solution for the remediation of heavy-metal-contaminated soils through the natural capabilities of plants. This study aims to investigate the effects of lead (Pb) and cadmium (Cd) metals on plant growth (e.g., seedling height, stem diameter, fresh and dry weight), physiological properties (e.g., tissue relative water content, tissue electrical conductivity), and biochemical parameters (e.g., chlorophyll content, superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) enzyme activities) of maize compared to the control group under greenhouse conditions at the Atatürk University Plant Production Application and Research Center. The results show that plant height decreased by 20% in the lead (Pb3000) application and by 42% in the cadmium (Cd300) application compared to the control group. The highest Pb dose (Pb3000) caused a 15% weight loss compared to the control, while the highest Cd dose (Cd300) caused a weight loss of 63%. The accumulation rates of heavy metals in soil, roots, and aboveground parts of plants indicated that maize absorbed and accumulated more Cd compared to Pb. Full article

Ultraviolet (UV) radiation effects on Earth’s ecosystems on a global scale can be assessed on a basis of satellite estimates of hyperspectral irradiance on the surface and in ocean waters and the spectral biological weighting functions. The satellite UV surface irradiance algorithms combine satellite retrievals of extraterrestrial solar irradiance, cloud/surface reflectivity, aerosol optical depth, and total column ozone with radiative transfer computations. The assessment of in-water irradiance requires additional information on inherent optical properties (IOPs) of ocean water. Our Ozone Monitoring Instrument (OMI) surface hyperspectral irradiance algorithm is updated by implementing a new absorbing aerosol correction based on OMI daily retrievals of UV aerosol absorption optical depth (AAOD). To provide insight into the temporal and spatial variability of absorbing aerosols, we consider a monthly global AAOD climatology derived from the OMI UV aerosol algorithm. Hyperspectral underwater irradiance is computed using Hydrolight radiative transfer calculations along with a Case I water model of IOPs extended into UV. Both planar and scalar irradiances are computed on the Earth’s surface and propagated underwater. The output surface products include the UV index. The output underwater products include the hyperspectral diffuse attenuation coefficients of the planar and scalar irradiances. Effects of the seasonal variability of AAOD on the UV index and the deoxyribonucleic acid (DNA) damage dose rates are considered. The reduction in the UV index and DNA damage dose rate due to the presence of absorbing aerosols can be as large as 30–40%. Full article

Melanoma is an aggressive disease that arises from mutations in the cells that produce the pigment melanin, melanocytes. Melanoma is characterized by a high mortality rate, due to avoidance of applied therapies and metastasis to other organs. The peculiar features of boron neutron capture therapy (BNCT), particularly its cell-level selectivity, make BNCT a promising modality for melanoma treatment. However, appropriate cellular models should be used to study new therapies or improve the efficacy of existing therapies. Spheroids, which have been used for years for in vitro studies of the efficacy of anti-cancer therapies, have many characteristics shared with tumors through which they can increase the accuracy of the cellular response compared to 2D culture in vitro studies and reduce the use of animals for research in the future. To the best of our knowledge, when we started researching the use of spheroids in BNCT in vitro, there was no publication showing such use. Our study aimed to evaluate the efficacy of a 3D cellular model (spheroids) for testing BNCT on melanoma cells. We assessed boronophenylalanine (¹⁰BPA) uptake using inductively coupled plasma mass spectrometry in both spheroids and 2D cultures of melanoma and melanocytes. DNA damage, Ki67 protein expression, and spheroid growth were analyzed. The experimental groups included: (1) IR_B (neutron flux + 50 µg ¹⁰B/mL), (2) IR (neutron flux alone), (3) C_B (no irradiation, 50 µg ¹⁰B/mL), and (4) C (no irradiation and no treatment with boron). The total absorbed doses were estimated to be 2.1–3.1 Gy for IR_B cells and spheroids as well as 8.3–9.4 Gy for IR_B spheroids, while estimated doses for IR cells were 0.5–1.9 Gy. The results indicated that IR_B spheroids might exhibit a reduced diameter. Melanoma cells in the 3D model showed that their DNA damage levels may be higher than those in the 2D model. Moreover, the Ki67 assay revealed differences in the expression of this marker between irradiated melanoma cell lines. In conclusion, preincubation with ¹⁰BPA enhances BNCT efficacy, leading to cell growth inhibition and increased DNA fragmentation. Differences in DNA damage between 2D and 3D models may be due to dissimilarities in cell metabolism caused by a changed cell architecture. Full article

Soil samples were collected from a college campus in Taiwan to measure the levels of radionuclides, contributing to the sustainable management of campus environments. A high-resolution HPGe gamma spectrometry system was utilized to measure the activity concentrations of natural radionuclides (²²⁶Ra, ²³²Th, and ⁴⁰K) and artificial radionuclide (¹³⁷Cs). The activity concentrations of ¹³⁷Cs were not detected in the campus soils, suggesting that artificial radionuclides did not contaminate the soil, supporting sustainable soil quality. However, the average concentrations of ²³²Th and ⁴⁰K with mean values of 53.4 ± 5.1 and 504.5 ± 75.4 Bq/kg dw were higher than the global soil average of 45 and 420 Bq/kg dw, respectively. Meanwhile, the average concentration of ²²⁶Ra with a mean value of 30.1 ± 3.0 Bq/kg dw was similar to the global soil average of 32 Bq/kg. The average outdoor absorbed gamma dose rate (D_ex) and annual effective doses (AED_ex), with a mean of 67.2 nGy/h and 82.4 μSv/y, were found to be higher than the average world levels of 57 nGy/h and 70 μSv/y, respectively. Despite these findings, the radium equivalent activity Ra_eq and external hazard index H_ex, with average values of 145.2 Bq/kg and 0.39, respectively, were below the recommended limit values of 370 Bq/kg and 1.0, respectively. This study provides useful information on the background radioactivity of the study campus, which is crucial for developing sustainable strategies to ensure a safe and healthy environment, indicating that there are no radiological hazards in the soil. Full article

The formation of an aluminosilicate gel structure made of alkali-activated materials (AAMs) was conducted through an alkali-activation reaction of the solid precursors (fly ash, metakaolin, and wood ash). Fly and wood ash are by-products of the burning process of coal and wood, respectively. Alkali-activated materials of aluminosilicate origin, made from the different ashes, fly and wood, are very attractive research targets and can be applied in various technological fields due to their thermal stability, resistance to thermal shock, high porosity, high sustainability, and finally, low energy loss during production. In this paper, we evaluate physico-chemical properties, microstructure, and radiological environmental impacts when wastes that contain elevated levels of naturally occurring radionuclides (NORs) such as fly ash and wood ash are made into “green cements” such as AAMs. The determination of radionuclide content was performed by means of gamma-ray spectrometry. Results showed that the AAMs have a lower value in the activity concentration of radionuclides than raw materials. The external absorbed gamma dose rate was 74.7–107.3 nGy/h, and the external radiation hazard index values were in range of 0.445–0.628 Bq/kg. The results of the activity concentration measurements for alkali-activated materials indicate the potential of their safe application in building construction. In terms of the structural characterizations, the obtained alkali-activated materials were examined using XRD, DRIFT, FESEM, and TEM analyses. Full article