Search Results (205)

This study evaluates lead-free high-density polyethylene (HDPE) composites reinforced with high-Z oxides (Bi₂O₃, WO₃, Gd₂O₃, TeO₂, and a Bi₂O₃/WO₃ hybrid) as lightweight materials for gamma-ray and fast-neutron shielding. A hybrid computational framework combining Phy-X/PSD with Geant4 Monte Carlo simulations was used to obtain key shielding parameters, including the linear and mass attenuation coefficients (μ, μ/ρ), half-value layer (HVL), mean free path (MFP), effective atomic number (Z_eff), effective electron density (N_eff), exposure and energy-absorption buildup factors (EBF, EABF), and fast-neutron removal cross section (Σ_R). The incorporation of heavy oxides produced a pronounced improvement in gamma-ray attenuation, particularly at low energies, where the linear attenuation coefficient increased from below 1 cm⁻¹ for neat HDPE to values exceeding 130–150 cm⁻¹ for Bi- and W-rich composites. In the intermediate Compton-scattering region (≈0.3–1 MeV), all oxide-reinforced systems maintained a clear attenuation advantage, with μ values around 0.12–0.13 cm⁻¹ compared with ≈0.07 cm⁻¹ for pure HDPE. At higher photon energies, the dense composites continued to outperform the polymer matrix, yielding μ values of approximately 0.07–0.09 cm⁻¹ versus ≈0.02 cm⁻¹ for HDPE due to enhanced pair-production interactions. The Bi₂O₃/WO₃ hybrid composite exhibited attenuation behavior comparable, and in some regions slightly exceeding, that of the single-oxide systems, indicating that mixed fillers can effectively balance density and shielding efficiency. Oxide addition significantly reduced exposure and energy-absorption buildup factors below 1 MeV, with a moderate increase at higher energies associated with secondary radiation processes. Fast-neutron removal cross sections were also modestly enhanced, with Gd₂O₃-containing composites showing the highest values due to the combined effects of hydrogen moderation and neutron capture. The close agreement between Phy-X/PSD and Geant4 results confirms the reliability of the dual-method approach. Overall, HDPE composites containing about 60 wt.% oxide filler offer a practical compromise between shielding performance, manufacturability, and environmental safety, making them promising candidates for medical, nuclear, and aerospace radiation-protection applications. Full article

In recent years, polymer-based hybrid nanocomposites have emerged as promising alternatives to traditional heavy metal shields due to their low density, flexibility, and environmental safety. In this study, the synthesis of PS-PEG copolymers and the gamma radiation-shielding properties of PS-PEG/As₂O₃, PS-PEG/BN, and PS-PEG/As₂O₃/BN nanocomposites with different compositions are investigated. The goal is to find the optimal nanocomposite composition for gamma radiation shielding and dosimetry. Therefore, the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), half-value layer (HVL), tenth-value layer (TVL), effective atomic number, mean free path (MFP), radiation shielding efficiency (RPE), electron density, and specific gamma-ray constant were presented. Gamma rays emitted by the Eu source were detected by a high-purity germanium (HPGe) detector device. GammaVision was used to analyze the given data. Photon energy was in the vicinity of 121.8–1408.0 keV. The MAC values in XCOM simulation tools were used to compute. Gamma-shielding efficiency was increased by an increased number of NPs at a smaller photon energy. At 121.8 keV, the HVL of a composite with 70 wt% As₂O₃ NPs is 2.00 cm, which is comparable to the HVL of lead (0.56 cm) at the same energy level. Due to the increasing need for lightweight, flexible, and lead-free shielding materials, PS-b-PEG copolymer-based nanocomposites reinforced with arsenic oxide and BN NPs will be materials of significant interest for next-generation radiation protection applications. Full article

Background: Excessive sun exposure is a major modifiable risk factor for skin cancer, with ultraviolet (UV) radiation identified as a key contributor. Saudi Arabia’s high UV index and hot climate increase the risk of photo-induced skin damage among residents. Although awareness of sun protection is growing, inconsistent use of preventive measures persists, often due to misconceptions and limited knowledge. This study aimed to assess patterns of current and prior sun exposure across demographic groups in Saudi Arabia using the validated Arabic version of the Sun Exposure and Behaviour Inventory (Ar-SEBI). Methods: An analytical cross-sectional study was conducted between August 2024 and January 2025 across all five Saudi regions using non-probability quota sampling to ensure geographic representation. Sun-exposure practices and protective behaviours were measured using the Ar-SEBI. Data were collected via an online questionnaire and analysed using IBM SPSS Statistics 26. Normality was assessed via Shapiro–Wilk and Levene’s tests. Depending on the distribution, data were analysed using the Mann–Whitney U test, the Kruskal–Wallis H test, unpaired t-tests, or ANOVA. A p-value < 0.05 was considered statistically significant. Results: A total of 11,491 adults participated. Significant demographic and regional differences in sun-related behaviours were observed. Overall, 72.7% of participants were unaware of the SPF level of their sunscreen. Males and individuals under 30 years of age had significantly higher sun exposure scores than females and older adults, respectively (p < 0.001). Residents of the Southern region had the highest exposure and behaviour scores (p < 0.001), despite also reporting higher engagement in some protective measures. Additionally, sun exposure scores increased progressively with darker Fitzpatrick skin types (IV–VI) (p < 0.001), suggesting a common belief that darker skin confers adequate protection. Conclusions: This study reveals notable disparities in sun-protection practices across Saudi Arabia. Younger adults, males, and individuals with darker skin types reported greater sun exposure and indicators of lower protective awareness. These findings support the need for targeted, culturally tailored public health campaigns and policy measures to enhance sun safety and reduce long-term dermatological risks. Full article

Radiology services play a vital role in modern healthcare, yet disparities in access and concerns about occupational radiation exposure remain understudied in many countries, including Kazakhstan. This study evaluates national trends in diagnostic imaging services, workforce distribution, and radiation-related anxiety among medical personnel. We analyzed national diagnostic imaging infrastructure and workforce data from 2018–2024. Individual radiation exposure data (n = 177) were obtained from dosimetry records in Astana’s medical facilities. Additionally, a cross-sectional survey (n = 324) was conducted using the Spielberger–Hanin Anxiety Scale to assess radiation-related anxiety and associated factors. Between 2018 and 2024, the number of CT rooms in Kazakhstan more than doubled from 162 to 358 (+121%), while X-ray examinations declined from 20.6 to 14.6 million (−29.2%) and fluorography dropped by 67.7%. CT scans increased over threefold, from 491,738 to 1.6 million. Radiologists grew from 3529 to 4511 (+27.8%), and ultrasound doctors from 1396 to 2178 (+56.1%). Interventional physicians had the highest quarterly radiation dose (0.65 ± 0.58 mSv, p = 0.001). Among radiology professionals, 32% reported anxiety related to occupational exposure. Anxiety was significantly associated with not using aprons (58% vs. 27%, p < 0.001), lack of dosimeter use (27% vs. 12%, p = 0.001), and inadequate safety training (27% vs. 6%, p < 0.001). Spielberger–Hanin scores ≥ 45 indicated high levels of situational (58%) and personal (56%) anxiety in this group. Kazakhstan’s diagnostic radiology capacity has grown rapidly, especially in CT availability, yet regional disparities and occupational anxiety remain critical concerns. Targeted workforce distribution, improved protective practices, and enhanced radiation safety education are urgently needed. Full article

This study investigates the design and experimental evaluation of Fe–B–Si-based bilayer composites engineered for dual shielding against gamma rays and thermal neutrons. The materials integrate a boron-enriched amorphous Fe matrix with surface coatings of high-Z fillers—lead (Pb) and tungsten (W)—dispersed in an epoxy resin. W or Pb powders (20–40 µm) were dispersed in epoxy resin at a high filler loading (60–70 wt% metal, approximately several tens to one by weight). This ensured a dense and uniform coating structure. The metallic fillers were high-purity (≥99.9%) powders. Gamma-ray attenuation was examined using ¹³⁷Cs and ⁶⁰Co sources at photon energies of 661.7, 1173, and 1332 keV, while thermal neutron shielding was assessed with a moderated Am-Be neutron source. The effects of boron concentration (13–21 at%) in the matrix and coating thickness (80–400 μm) were systematically evaluated. Increasing boron content markedly enhanced thermal neutron attenuation, reaching up to 29%, whereas Pb- and W-filled coatings achieved more than 85% gamma-ray attenuation at 661.7 keV. All measurements were repeated three times; standard deviations were below 2% across conditions, confirming reproducibility and indirectly indicating uniform coating dispersion. At 661.7 keV, the half-value and tenth-value layers (HVL/TVL) were derived from the measured linear attenuation coefficients to benchmark performance. Notably, W coatings delivered shielding efficiency comparable to Pb while offering advantages in environmental safety, mechanical robustness, and regulatory compliance. These results highlight the potential of Fe–B–Si bilayer composites as lightweight, scalable, and lead-free shielding materials for aerospace electronics, portable radiation protection devices, and modular panels for satellites and nuclear facilities. Full article

This study aimed to assess oxidative DNA damage products in healthcare workers who are directly exposed to or use ionizing radiation in their work. In the study, three groups were defined based on the probability of radiation exposure, ranging from the highest-risk group to the lowest, with the fourth group designated as the control group. First, a questionnaire was administered to the participants, and then their first morning urine samples were taken to detect oxidative DNA damage markers. According to the Kruskal-Wallis test results among the four groups in our study, statistically significant differences were found only in terms of age, height, and weight (p values = 0.011, 0.038, and 0.003, respectively). However, it was observed that there was no significant relationship between the oxidative DNA damage parameters 8-hydroxy-2′-deoxyguanosine (8-OH-dG), and 8,5′-cyclo-2′-deoxyadenosines (S- and R-cdA) in relation to radiation exposure, with p-values of 0.132, 0.179, and 0.611, respectively. The study’s results revealed that exposure to ionizing radiation did not cause a significant increase in urinary oxidative DNA damage markers. This outcome may be associated with the effective use of personal protective equipment and strict adherence to radiation safety protocols among healthcare workers. Full article

In 2011, the International Commission on Radiological Protection (ICRP) recommended reducing the annual equivalent dose limit to the eye lens. This study investigated the effects of physician height and years of experience on lens radiation exposure in a clinical setting. The lens dose was measured using the DOSIRIS dosimeter, which quantified Hp(3) while accounting for the shielding effect of lead glasses, and a neck dosimeter for Hp(0.07). A significant negative correlation was found between physician height and both Hp(0.07) (R = −0.642) and Hp(3) (R = −0.728), suggesting that taller physicians received lower lens doses because of their greater distance from the scatter source. A positive correlation was observed between years of experience and Hp(0.07) (R = 0.650). Two-group comparisons showed that physicians shorter than 170 cm had a 2.77-fold higher median Hp(3) than those ≥170 cm (p < 0.05). As experienced physicians may be exposed to higher radiation levels, regular review of protective practices and continued radiation safety education are essential, regardless of clinical experience. This is the first clinical study to simultaneously evaluate the effects of physician height and experience on lens dose in interventional cardiology. Regular review of protective practices remains essential regardless of operator height or experience. Full article

Ensuring the quality and safety of agricultural and food products is crucial for protecting consumer health, meeting market expectations, and complying with regulatory requirements. Quality and safety parameters are commonly assessed using chemical and microbiological analyses, which are time-consuming, impractical, and involve the use of toxic solvents, often disrupting the material’s original structure. An alternative technique, infrared spectroscopy, including near-infrared (NIR), mid-infrared (MIR), and short-wave infrared (SWIR), has emerged as a rapid, powerful, and minimally destructive technique for evaluating the quality and safety of food and agricultural products. This review focuses on discussing MIR spectroscopy, particularly Fourier transform infrared (FTIR) techniques, with emphasis on the attenuated total reflectance (ATR) measurement mode (globar infrared light source is commonly used) and on the use of synchrotron radiation (SR) as an alternative high-brightness light source. Both approaches enable the extraction of detailed spectral data related to molecular and functional attributes concerning quality and safety, thereby facilitating the assessment of crop disorders, food chemical composition, microbial contamination (e.g., mycotoxins, bacteria), and the detection of food adulterants, among several other applications. In combination with advanced chemometric techniques, FTIR spectroscopy, whether employing ATR as a measurement mode or SR as a high-brightness light source, is a powerful analytical tool for classification based on attributes, variety, nutritional and geographical origins, with or without minimal sample preparation, no chemical use, and short analysis time. However, limitations exist regarding calibrations, validations, and accessibility. The objective of this review is to address recent technological advancements and existing constraints of FTIR conducted in ATR mode and using SR as a light source (not necessarily in combination). It defines potential pathways for the comprehensive integration of FTIR and chemometrics for real-time quality and safety monitoring systems into the global food supply chain. Full article

Aim: Radiation exposure is a growing public health concern; however, public understanding of its sources, risks, and protective measures remains limited. This study examined familiarity, misconceptions, and attitudes towards both ionising and nonionising radiation among residents of Saudi Arabia, an area that has received limited attention in the literature. Methods: A cross-sectional survey was conducted among 888 Saudi residents aged 18 years and above by using a validated online questionnaire. The instrument comprised demographic items, 13 statements assessing radiation familiarity (including knowledge of sources and safety), and 21 items assessing attitudes (including safety practices and willingness to receive further education), all rated on a five-point Likert scale. Descriptive statistics and nonparametric inferential analyses were performed using SPSS v27. Results: Participants had a moderate mean familiarity score (3.34 ± 1.16), whereas attitude scores were high (3.56 ± 1.14). Demographic variables, including age, sex, region, and previous training, significantly affected familiarity and attitudes. A medical background and previous radiation education were associated with a higher familiarity level. Nonetheless, most participants expressed a strong interest in acquiring additional knowledge. Conclusion: Moderate familiarity with radiation and strong attitudes towards protection among the Saudi public highlight opportunities to strengthen practical safety knowledge. These findings indicate the need for targeted, accessible educational initiatives, particularly through digital platforms, to enhance radiation literacy and support the objectives of Saudi Vision 2030. Full article

Ready-to-eat products, such as mixed-cut leafy vegetables, require packaging that provides adequate mechanical protection, a barrier against UV radiation, gases, and water vapor, as well as microbiological safety. In this study, thin films made of polybutylene succinate (PBS) and poly (butylene succinate-dilinoleic succinate) (PBS-DLS) copolyester were prepared by casting a film-forming solution onto a glass plate and spreading it with a roller. These films were compared to commercial thin films made of oriented polypropylene (OPP). OPP films exhibited ten times higher tensile strength than PBS films (104.36 ± 10.03 MPa for OPP, 10.96 ± 0.68 MPa for PBS, and 6.36 ± 0.62 MPa for PBS-DLS). Incorporation of co-monomeric units of dilinoleic succinate (DLS) into PBS structure significantly improved elongation at break, increasing from 38.16% ± 12.36% for PBS to 132.30% ± 25.08% for PBS-DLS. However, commercial OPP had the highest elongation at break, reaching 231.84% ± 20.30%. OPP films exhibited the highest transparency in the visible light range but also in the UV range. In contrast, PBS and PBS-DLS films provided better UV radiation blocking. The films were used to create sachets by heat sealing, into which freshly cut chicory leaves were placed. The packaged product was stored under refrigerated conditions for 48 h and 120 h. While OPP and PBS-DLS films provided good protection against moisture loss in chicory, leaves packed in PBS sachets lost significant weight during storage. The packaged product contained considerable microbial contamination, but the type of packaging did not influence its reduction or increase. Ultimately, the PBS-DLS copolymer exhibited higher elongation at break and greater water vapor barrier properties than PBS. Protection against moisture loss in packaged chicory for PBS-DLS packaging was similar to that for commercial OPP. Despite their weaker mechanical properties, PBS-DLS films appear to be a promising alternative to OPP films for packaging fresh food products. Full article

Digital subtraction angiography (DSA) remains an important reference modality for evaluating chronic limb-threatening ischemia (CLTI), with left transradial access (TRA) increasingly favored for its lower complication rates and patient comfort. Radiation safety for operators is paramount, yet the impact of patient positioning on scatter radiation during lower limb diagnostic catheter angiography (CA) is understudied. This single-center randomized controlled trial evaluated whether head-first (HF) vs. feet-first (FF) supine patient orientation affects operator radiation exposure during lower extremity CA from left TRA. Between February and August 2024, 24 patients with CLTI were enrolled and randomized to HF or FF positions. Operator radiation exposure was measured using thermoluminescent dosimeters (TLDs) at the eye, chest, and left ring finger. Background radiation was subtracted. Procedures were standardized and performed by a single experienced interventional radiologist. Fluoroscopy time, dose area product (DAP), and contrast usage were recorded. No statistically significant differences were found between groups in patient BMI and procedural parameters. Patient positioning (HF vs. FF) did not significantly impact operator radiation exposure. A trend toward higher finger exposure in FF position suggests the need for optimized hand protection. These findings support flexible patient positioning without compromising operator safety, reinforcing adherence to ALARA principles. Full article

Background: The relationship between occupational sun exposure and melanoma risk is complex and multifaceted, with existing evidence yielding contradictory findings. Unlike Non-Melanoma Skin Cancer (NMSC), for which occupational sun exposure is a well-established risk factor, the link with cutaneous melanoma remains contentious. Objectives: This study aimed to evaluate whether, in a cohort of patients with cutaneous melanoma, an association existed between occupational sun exposure and melanoma, specifically with histotype, site of occurrence, and Breslow index. Methods: This is a retrospective cohort analysis conducted to evaluate whether occupational sun exposure constitutes a risk factor for the development of cutaneous melanoma in patients diagnosed between January 2005 and October 2023 at the Dermatology Unit, Azienda USL Toscana Centro, Florence. Occupational ultraviolet (UV) exposure was examined by classifying each participant’s job into categories based on solar UV exposure levels—outdoor (e.g., agriculture and construction roles), mixed indoor/outdoor (e.g., trades and public safety professions), and indoor settings (e.g., office-based work). Results: A final total of 1417 patients were analyzed. Occupational categorization revealed that 1171 patients (82.64%) were classified as non-occupationally exposed (indoor), while 246 (17.36%) were occupationally exposed to solar UV radiation (including 14.82% mixed indoor/outdoor and 2.54% outdoor workers). A significant association was observed between occupational sun exposure and lentigo maligna, which was more prevalent among exposed workers and even more so in the outdoor subgroup. Anatomical site distribution exhibited a significant association with occupational sun exposure. Indeed occupationally exposed individuals showed a higher prevalence of melanomas in the head and neck region, a distribution pattern particularly evident among outdoor workers, suggesting that these sites may be more susceptible to chronic sun exposure in outdoor and mixed occupations. Moreover, a significant association was found between occupational exposure and Breslow thickness, with exposed workers presenting with thicker melanomas at diagnosis, suggesting more advanced disease. Conclusions: The finding of this study may reflect variations in occupational sun exposure patterns and warrants further investigation into protective measures and early-detection strategies tailored to occupational groups. Full article

Ultraviolet radiation (UVR) represents significant risks to both textile durability and human health. Natural dyes are gaining attention as eco-friendly alternatives to synthetic UV-blocking agents, offering aesthetic and functional benefits. This study explores the UV-protective properties of 100% cotton knit fabrics dyed with natural dyes—indigo, weld, and madder—using different mordanting processes, including materials with mordant abilities such as alum, pomegranate peel, and tannin extracted from quebracho. Twenty samples were evaluated, including undyed, individually treated, and combined dye-mordant formulations. UV protection was assessed through spectral transmittance and Ultraviolet Protection Factor (UPF) measurements before and after washing. The results showed that natural dyes significantly improved the UV resistance of cotton fabrics, particularly when combined with products like pomegranate and the tannin–alum mixture. Notably, some samples demonstrated improved UPF and became darker after washing, such as mordant combinations like tannin with alum. These findings suggest that natural dye, when combined with appropriate mordants, offers a sustainable and effective approach to producing UV-protective textiles. This is particularly valuable in children’s clothing, where chemical safety and sun protection are crucial. Future research should investigate the influence of pH on dye stability and UV-blocking performance to optimise formulations for industrial use and long-term functionality. Full article

Rapid urbanization and climate change have intensified urban flood risks, necessitating resilient upstream infrastructure to ensure metropolitan water security and effective flood mitigation. Gravity dams, as critical components of urban flood protection systems, regulate discharge to downstream urban areas. Gravity dams are critical for regulating flood discharge, yet their seismic vulnerability poses significant challenges, particularly under compound effects involving concurrent seismic loading and climate-induced elevated reservoir levels. This study introduces a novel seismic analysis framework for gravity dams using the scaled boundary finite element method (SBFEM), which efficiently models dam–water and dam–foundation interactions in infinite domains. A two-dimensional numerical model of a concrete gravity dam, subjected to realistic seismic loading, was developed and validated against analytical solutions and conventional finite element method (FEM) results, achieving discrepancies as low as 0.95% for static displacements and 0.21% for natural frequencies. The SBFEM approach accurately captures hydrodynamic pressures and radiation damping, revealing peak pressures at the dam heel during resonance and demonstrating computational efficiency with significantly reduced nodal requirements compared to FEM. These findings enhance understanding of dam behavior under extreme loading. The proposed framework supports climate-adaptive design standards and integrated hydrological–structural modeling. By addressing the seismic safety of flood-control dams, this research contributes to the development of resilient urban water management systems capable of protecting metropolitan areas from compound climatic and seismic extremes. Full article

In the field of high-altitude operations, the frequent occurrence of fall accidents is usually closely related to safety measures such as the incorrect use of safety locks and the wrong installation of safety belts. At present, the manual inspection method cannot achieve real-time monitoring of the safety status of the operators and is prone to serious consequences due to human negligence. This paper designs a new type of high-altitude operation safety device based on the STM32F103 microcontroller. This device integrates ultra-wideband (UWB) ranging technology, thin-film piezoresistive stress sensors, Beidou positioning, intelligent voice alarm, and intelligent safety lock. By fusing five modes, it realizes the functions of safety status detection and precise positioning. It can provide precise geographical coordinate positioning and vertical ground distance for the workers, ensuring the safety and standardization of the operation process. This safety device adopts multi-modal fusion high-altitude operation safety monitoring technology. The UWB module adopts a bidirectional ranging algorithm to achieve centimeter-level ranging accuracy. It can accurately determine dangerous heights of 2 m or more even in non-line-of-sight environments. The vertical ranging upper limit can reach 50 m, which can meet the maintenance height requirements of most transmission and distribution line towers. It uses a silicon carbide MEMS piezoresistive sensor innovatively, which is sensitive to stress detection and resistant to high temperatures and radiation. It builds a Beidou and Bluetooth cooperative positioning system, which can achieve centimeter-level positioning accuracy and an identification accuracy rate of over 99%. It can maintain meter-level positioning accuracy of geographical coordinates in complex environments. The development of this safety device can build a comprehensive and intelligent safety protection barrier for workers engaged in high-altitude operations. Full article