Hasil untuk "Radioactivity and radioactive substances"

Huu-Huy-Hoang Tran, Gia-Bao Duong, Quoc-Viet-Anh Tran et al.

Extracting drug use information from unstructured Electronic Health Records remains a major challenge in clinical Natural Language Processing. While Large Language Models demonstrate advancements, their use in clinical NLP is limited by concerns over trust, control, and efficiency. To address this, we present NOWJ submission to the ToxHabits Shared Task at BioCreative IX. This task targets the detection of toxic substance use and contextual attributes in Spanish clinical texts, a domain-specific, low-resource setting. We propose a multi-output ensemble system tackling both Subtask 1 - ToxNER and Subtask 2 - ToxUse. Our system integrates BETO with a CRF layer for sequence labeling, employs diverse training strategies, and uses sentence filtering to boost precision. Our top run achieved 0.94 F1 and 0.97 precision for Trigger Detection, and 0.91 F1 for Argument Detection.

Badhan Mazumder, Sir-Lord Wiafe, Vince D. Calhoun et al.

Early identification of adolescents at risk for substance use initiation (SUI) is vital yet difficult, as most predictors treat connectivity as static or cross-sectional and miss how brain networks change over time and with behavior. We proposed NeuroBRIDGE (Behavior conditioned RIemannian Koopman Dynamics on lonGitudinal connEctomes), a novel graph neural network-based framework that aligns longitudinal functional connectome in a Riemannian tangent space and couples dual-time attention with behavioral-conditioned Koopman dynamics to capture temporal change. Evaluated on ABCD, NeuroBRIDGE improved future SUI prediction over relevant baselines while offering interpretable insights into neural pathways, refining our understanding of neurodevelopmental risk and informing targeted prevention.

L. E. Sinclair, P. R. B. Saull, A. McCann et al.

Nuclear security operations and forensic investigations require the utilization of a suite of instruments ranging from passive gamma spectrometers to high-precision laboratory sample analyzers. Gamma spectroscopy survey is further broken down into wide-area search performed with large-volume scintillator-based mobile survey spectrometers which are integrated with geographic position sensors for mapping and identification of hot zones, and high-precision long-dwell measurements using solid state spectrometers for follow-on characterization to establish isotopic content and ratios. While performing well at detecting the presence, quantity and type of radioactivity, all of these methods have limited ability to determine the location of a source of radioactivity. In recent years, technology advances have resulted in gamma imager devices which can create an image of the distribution of radioactive sources using the gamma emissions which accompany radioactive decay, and overlay this on an optical photograph of the environment. These gamma imaging devices have arisen out of methods developed for medical physics, experimental particle physics, and astrophysics, resulting in a proliferation of different technological approaches. Those responsible for establishing a nuclear security concept of operations, require guidance to choose the proper gamma imager for each of the application spaces in a tiered response. Here the results of an intercomparison of two gamma imagers based on two widely different technologies, semiconductor and scintillator detectors, are presented. The optimal utilization of these imaging technologies in a tiered response is discussed based on the results of the trial. Finally, an outlook on future directions for gamma imaging advances is provided.

Yu. N. Kapyrina, A. M. Biblin, A. V. Vodovatov et al.

Sources of ionizing radiation are an integral part of modern healthcare and are widely used for diagnostic and therapeutic purposes. One of the key aspects of the safe use of ionizing radiation in medicine is the competence of medical professionals in the field of radiation protection. The aim of this study is to investigate the level of awareness and understanding of radiation protection among interventional radiologists in the Russian Federation. The research was conducted through an online survey. The link to the questionnaire was shared in communities of interventional radiologists in social networks. A total of 78 interventional radiologists participated in the survey. The questionnaire consisted of 26 questions, 11 of which focused on assessing knowledge of radiation protection. Each question addressed a fundamental aspect essential for understanding and application in medical practice. None of the respondents answered all radiation protection questions correctly. The average score among all participants was 6.1 out of a maximum of 11. The level of knowledge did not significantly depend on years of professional experience (p>0,05). The most challenging questions concerned the biological effects of ionizing radiation. Most participants assessed their knowledge of radiation safety as satisfactory (46,1%) or good (33,3%). Self-assessment of knowledge levels also did not significantly depend on professional experience (p>0,05). As preferred sources of information on radiation safety, interventional radiologists identified online resources, scientific conferences, educational materials, and training courses. Currently, no regularly updated, unified information online resource in Russian is available. Developing such a resource represents the most cost-effective approach to ensuring and improving the awareness of interventional radiologists regarding radiation protection. Simultaneously, efforts should be directed toward enhancing the quality of training courses on radiation protection.

Xu-Nan Guo, Chang Cai, Fei Gao et al.

We present the preparation and measurement of the radioactive isotope $\rm ^{37}Ar$, which was produced using thermal neutrons from a reactor, as a calibration source for liquid xenon time projection chambers. $\rm ^{37}Ar$ is a low-energy calibration source with a half-life of 35.01 days, making it suitable for calibration in the low-energy region of liquid xenon dark-matter experiments. Radioactive isotope $\rm ^{37}Ar$ was produced by irradiating $\rm ^{36}Ar$ with thermal neutrons. It was subsequently measured in a gaseous xenon time projection chamber (GXe TPC) to validate its radioactivity. Our results demonstrate that $\rm ^{37}Ar$ is an effective and viable calibration source that offers precise calibration capabilities in the low-energy domain of xenon-based detectors.

Sukanya Krishna, Marie-Laure Charpignon, Maimuna Majumder

Substance overdose mortality in the United States claimed over 80,000 lives in 2023, with the COVID-19 pandemic exacerbating existing trends through healthcare disruptions and behavioral changes. Estimating excess mortality, defined as deaths beyond expected levels based on pre-pandemic patterns, is essential for understanding pandemic impacts and informing intervention strategies. However, traditional statistical methods like SARIMA assume linearity, stationarity, and fixed seasonality, which may not hold under structural disruptions. We present a systematic comparison of SARIMA against three deep learning (DL) architectures (LSTM, Seq2Seq, and Transformer) for counterfactual mortality estimation using national CDC data (2015-2019 for training/validation, 2020-2023 for projection). We contribute empirical evidence that LSTM achieves superior point estimation (17.08% MAPE vs. 23.88% for SARIMA) and better-calibrated uncertainty (68.8% vs. 47.9% prediction interval coverage) when projecting under regime change. We also demonstrate that attention-based models (Seq2Seq, Transformer) underperform due to overfitting to historical means rather than capturing emergent trends. Ourreproducible pipeline incorporates conformal prediction intervals and convergence analysis across 60+ trials per configuration, and we provide an open-source framework deployable with 15 state health departments. Our findings establish that carefully validated DL models can provide more reliable counterfactual estimates than traditional methods for public health planning, while highlighting the need for calibration techniques when deploying neural forecasting in high-stakes domains.

Christopher Rääf, Johan Martinsson, Mats Eriksson et al.

V. S. Repin, V. P. Ramzaev, A. M. Biblin et al.

The designation of peaceful nuclear explosions as special radioactive waste imposes serious requirements to the territory of the explosion, its boundaries, and stakeholders informing about the prohibition of economic activities within these boundaries. The acting Sanitary Norms and Rules SanPiN 2.6.1.2819–10 “Ensuring radiation safety of the population living in areas where nuclear explosions were conducted (1965–1988) for peaceful purposes” do not define the size of the boundaries of protected zones. The aim of this paper is to analyze the scientific literature on the structure of deformation changes in the Earth’s interior due to peaceful nuclear explosions and to justify quantitative ratios on the basis of which the size of protected zones can be estimated. The quantitative ratios were selected on the basis of a comparative analysis of the literature data. Using the ratios values made it possible to calculate the radii of deformation changes (cavities, crushing zones, fracturing zones, and zones of residual deformations) in various rocks. It is shown that the maximum values of fracturing radii for peaceful nuclear explosions carried out on the territory of the Russian Federation in hard rocks and in plastic rocks do not exceed 200 m and 250 m, respectively.

Mariana Alonso Natividade, Thessa Cristina Alonso, Amir Zacarias Mesquita

Food irradiation consists of a physical process that subjects food to doses of ionizing radiation, which are high enough energy to eliminate or neutralize harmful microbial contaminants without changing the taste or texture of food and without leaving residues. With this irradiation process we can prevent diseases transmitted by food, such as Salmonella and Escherichia coli, prolong the shelf life of foods, control pests that harm fruits by delaying germination and ripening, and finally sterilization, which allows their storage for years without refrigeration. The use of ionizing radiation for food preservation has been studied for several decades and is regulated in the USA by the Food and Drug Administration –FDA. In 1997, the World Health Organization - WHO released the use of the technique for all types of food. In Brazil, the first studies on food irradiation were carried out by the Center for Nuclear Energy in Agriculture - Cena, in the 50's. Currently, Brazilian legislation follows the international recommendations suggested by the Food and Agriculture Organization - FAO, the International Atomic Energy Agency - IAEA and Codex Alimentarius. The scope of this work is a survey, analysis and evolution of national and international legislation related to ionizing irradiation practices in food. For the preparation of this research, bibliographical reviews were carried out, consultations in Brazilian and international legislation, Internet sites, and in the documentation of the Gamma Irradiation Laboratory of the Nuclear Technology Development Center - CDTN

Swati Thakur, Soni Devi, Sanjeet S. Kaintura et al.

Low background gamma spectrometry employing HPGe detectors is a sensitive technique for measuring low-level radioactivity in environmental applications, material screening, and for rare decay searches. This work presents spectroscopic performance evaluation and modelling of a low background measurement setup developed at IIT Ropar in Punjab, India, to measure trace natural radioactive elements, with a particular interest in studying low-level radioactivity in soil and/or rock samples to generate specific inputs for low background experiments. The performance test and characterization of a low background cryocooled HPGe detector with relative efficiency of $\sim$33% have been carried out. An effective detector model has been developed using GEANT4 Monte Carlo simulation to determine the response of the detector over an energy range of 80.9-1408 keV and compared with the experimental performance of the detector. The response of the detector obtained using Monte Carlo simulations agrees reasonably well within 93% level of confidence, indicating only 7% deviation in the comparison. The present setup offers improved detection limits of primordial radionuclides (U/Th and K) to measure radioactive contamination in environmental matrices, which has been used elsewhere [1].

The JUNO Collaboration

The Jiangmen Underground Neutrino Observatory (JUNO) is a large scale neutrino experiment with multiple physics goals including deter mining the neutrino mass hierarchy, the accurate measurement of neutrino oscillation parameters, the neutrino detection from the super nova, the Sun, and the Earth, etc. JUNO puts forward physically and technologically stringent requirements for its central detector (CD), including a large volume and target mass (20 kt liquid scintillator, LS), a high energy resolution (3% at 1 MeV), a high light transmittance, the largest possible photomultiplier (PMT) coverage, the lowest possible radioactive background, etc. The CD design, using a spherical acrylic vessel with a diameter of 35.4 m to contain the LS and a stainless steel structure to support the acrylic vessel and PMTs, was chosen and optimized. The acrylic vessel and the stainless steel structure will be immersed in pure water to shield the radioactive back ground and bear great buoyancy. The challenging requirements of the acrylic sphere have been achieved, such as a low intrinsic radioactivity and high transmittance of the manufactured acrylic panels, the tensile and compressive acrylic node design with embedded stainless steel pad, one-time polymerization for multiple bonding lines. Moreover, several technical challenges of the stainless steel structure have been solved: the production of low radioactivity stainless steel material, the deformation and precision control during production and assembly, the usage of high strength stainless steel rivet bolt and of high friction efficient linkage plate. Finally, the design of the ancillary equipment like the LS filling, overflowing and circulating system was done.

P.Ye. Krivitskiy, N.V. Larionova, Yu.V. Baklanova et al.

Elaine Cavalcanti Rodrigues Vaz, Thiago Domingues, Thayná Emilly Cavalcante Santos et al.

Cutaneous production of vitamin D by exposure of the skin to solar radiation can provide more than 90% of the daily dose needed by the human body, thanks to the range of UV radiation covered by its spectrum and may be the best option to reduce oral supplementation. The process can be monitored by personal UV dosimetry since this is the range of solar radiation related to its production. Aiming to monitor UVB dose looking for correlation with skin production of vitamin D3, a printed strip with the molecular dosimetry device was used to produce a photonic signal as input for calculations in software developed here to run on a smartphone. For this, the molecular dosimeter Eu(btfa)3·bipy was prepared to be printed as a functional ink with a MEMS-based Drop-on-Demand Dimatix DMP2831 Materials Printer to produce the functional paper strips.  To use our personal UV molecular dosimeter photonic signal as input data, a correlation curve must be established to convert the UV dose into the amount of vitamin D3 produced. There is a promising solution for personal monitoring of cutaneous vitamin D production by printable UV dosimeter targets, aiming to contribute to a better immune response of individuals. In addition, the creation of a cloud data lake capable of mapping population data on vitamin D deficiency can help define public health policies.

Daiane Cristini Barbosa Souza, Roberto Vicente, Lídia Vasconcellos de Sá et al.

The application of ionizing radiation in diagnostic medicine has increased worldwide in the last decades. Computed Tomography (CT) is the main radiological procedure that contributes to the increase of the collective dose in the population. The aim of this study was to estimate the doses received by patients undergoing CT scans in a public hospital in Santa Catarina - Brazil, employing data from the DICOM header and utilizing the CT-Expo V. 2.7 software. The data were selected from 45 abdominal CT scans, performed consisted of two series: pre-contrast and one post-contrast intravenous, of adult patients performed in December 2020 in a public hospital located in Santa Catarina - Brazil. The spreadsheets with the data extracted from the DICOM headers were provided by the Santa Catarina Telemedicine System (STT). The effective dose and organ doses were calculated by CTDIvol and DLP values using the software. Overall, the organs that showed the higher equivalent doses were kidneys (19.5 mSv), spleen (18.5 mSv), stomach (18.9 mSv), and liver (18.1 mSv). The estimated effective doses were 7.31 and 8.41 mSv, for non-contrast and contrast-enhanced examinations. The use of software such as CT-Expo can support the estimation of effective doses received by patients through the information extracted from the DICOM header. The presented methodology can be a useful tool to retrospectively estimate the doses in CT services in Brazil.

L. Cardani, I. Colantoni, A. Cruciani et al.

Radioactivity was recently discovered as a source of decoherence and correlated errors for the real-world implementation of superconducting quantum processors. In this work, we measure levels of radioactivity present in a typical laboratory environment (from muons, neutrons, and gamma's emitted by naturally occurring radioactive isotopes) and in the most commonly used materials for the assembly and operation of state-of-the-art superconducting qubits. We develop a GEANT-4 based simulation to predict the rate of impacts and the amount of energy released in a qubit chip from each of the mentioned sources. We finally propose mitigation strategies for the operation of next-generation qubits in a radio-pure environment.

A. Jacobs, C. Andreoiu, J. Bergmann et al.

The performance of high-precision mass spectrometry of radioactive isotopes can often be hindered by large amounts of contamination, including molecular species, stemming from the production of the radioactive beam. In this paper, we report on the development of Collision-Induced Dissociation (CID) as a means of background reduction for experiments at TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). This study was conducted to characterize the quality and purity of radioactive ion beams and the reduction of molecular contaminants to allow for mass measurements of radioactive isotopes to be done further from nuclear stability. This is the first demonstration of CID at an ISOL-type radioactive ion beam facility, and it is shown that molecular contamination can be reduced up to an order of magnitude.

D. Nguyen, Huan Dinh Trinh, Tuong Phan

The rare earth mine containing high concentrations of natural radionuclides (238U, 232Th, and 40K) in Muong Hum commune, Nam Pung, Bat Xat district, Lao Cai province, a mine with large reserves of rare earth resources in Vietnam, will be exploited and processed in the near future. The activity of natural radionuclides in the environment of air, soil, water, and effective annual dose are important parameters in assessing the impact of radiation on the environment when the mine goes into operating and processing rare earth ore. Investigating and determining radioactivity in soil, water, and plants at Muong Hum rare earth mine by means of radioactive gas measurement (RAD-7), gamma radiation dose rate (DKS-96), sample analysis using an ICP-MS mass spectrometer, will be performed in this study. The results showed that some soil samples had radionuclides activity 238U, 232Th higher than the allowed standard. The annual effective dose value in the region is 6.1 times higher than the world average (2.4 mSv/year). The obtained results are the basis for monitoring the impact of the radioactive environment and providing solutions to minimize the effects of radioactive substances on the ecological environment when the mine goes into mining and processing of rare earth ores.

Amanda Cristina Ramos Koike, Elias Silva Araújo, Bianca Guimarães Negrão et al.

The tendency to use edible flowers in gastronomy to add beauty, color, and flavor in food preparation has been increasing in recent years. Several species have active biological substances, which play an important role in health maintenance. This highly perishable food should be grown without the use of pesticides. Thus, several methods are applied to increase the shelf life of food products, as well as ensure their quality and safety. Among the treatments, the food irradiation process has proven to be an effective tool in preserving and extending the shelf life of the perishable product. Dianthus chinensis flowers, popularly known as chinese pink (cravina), belongs to the family Caryophyllaceae, are native to Asia and Europe, are widely used in culinary preparations, is also acknowledged for their bioactive components and antioxidant properties. The purpose of this study was to evaluate carotenoids in D. chinensis flowers submitted to gamma irradiation and electron beam doses of 0.5, 0.8, and 1.0 kGy. High performance liquid chromatography was used to carotenoids determination. In the specie of edible flowers analyzed it was found carotenoid lutein (4.02 to x 7.52 mg/ 100 g). In general, the lutein was higher for irradiated samples, especially those treated with 0.8 and 1.0 kGy independently of irradiation technology. Accordingly, the applied irradiation treatments seemed to represent a feasible technology to preserve the quality of edible flower petals.

Francisco Rogerio Teixeira Nascimento

This work presents a computational simulation of a single Taylor bubble rising in a vertical column of stagnant liquid. The computational simulation was based on the Navier-Stokes equations for isothermal, incompressible, and laminar flow, solved by using the open source software OpenFOAM. The two fluids were assumed immiscible. The governing equations were discretized by the volume-of-fluid (VOF) method and solved using the Gauss iteration method. Parametric mesh was used in order to improve the modeling of curvilinear geometry. Numerical solutions were obtained for the rise velocities and shapes of the bubbles which are in excellent agreement with experimental data and correlations from literature.

Claudia Giovedi, Alfredo Abe, Rafael O. R. Muniz et al.

Accident tolerant fuels (ATF) has been studied since the Fukushima Daiichi accident in the research efforts to develop new materials which under accident scenarios could maintain the fuel rod integrity for a longer period compared to the cladding and fuel system usually utilized in Pressurized Water Reactors (PWR). The efforts have been focused on new materials applied as cladding, then iron-base alloys appear as a possible candidate. The aim of this paper is to implement modifications in a fuel performance code to evaluate the behavior of iron-based alloys under Loss-of-Coolant Accident (LOCA) scenario. For this, initially the properties related to the thermal and mechanical behavior of iron-based alloys were obtained from the literature, appropriately adapted and introduced in the fuel performance code subroutines. The adopted approach was step by step modifications, where different versions of the code were created. The assessment of the implemented modification was carried out simulating an experiment available in the open literature (IFA-650.5) related to zirconium-based alloy fuel rods submitted to LOCA conditions. The obtained results for the iron-based alloy were compared to those obtained using the regular version of the fuel performance code for zircaloy-4. The obtained results have shown that the most important properties to be changed are those from the subroutines related to the mechanical properties of the cladding. The results obtained have shown that the burst is observed at a longer time for fuel rods with iron-based alloy, indicating the potentiality of this material to be used as cladding with ATF purposes.