Hasil untuk "Radioactivity and radioactive substances"

Aline Leone Muguet Pinto, Marcos Antonio Scapin, Alexandre Luiz de Souza et al.

Oil sludge is a waste product generated by the oil industry, comprising organic substances (primarily long-chain polyaromatic, aromatic, and aliphatic hydrocarbons), inorganic compounds (such as sediments and metallic and non-metallic oxides), water, and oil processing residues. Radionuclides from the 238U and 232Th decay chains can be present in oil sludge, which justifies its classification as naturally occurring radioactive material (NORM). The oil industry produces approximately 60 million tons of oil sludge annually. Given the continuous generation of this waste, the development of additional storage sites will be necessary, incurring substantial costs. Furthermore, the storage and transportation of oil sludge pose significant environmental contamination risks. Due to its complex and heterogeneous composition, establishing a standardized methodology for classifying oil sludge presents considerable challenges. The development of an effective methodology for the analysis and classification of oil sludge is essential for proper waste management, as well as for facilitating the creation of treatment and reuse alternatives. X-ray fluorescence spectrometry (XRF) emerges as a promising analytical technique for classifying oil sludge, enabling direct, non-destructive analysis, thereby reducing both waste and analysis costs. In this study, wavelength dispersive X-ray fluorescence (WDXRF) and energy dispersive X-ray fluorescence (EDXRF) techniques were compared to assess their performance in analyzing the major (1–100%) and minor (0.01–0.99%) constituents in oil sludge samples. The elements were quantified using the Fundamental Parameters (FP) algorithm. The objective of this work is to develop a methodology for determining both major and minor elements in oil sludge, contributing to a more effective management of this waste.

Carla Ricardo, Sâmella Andrade Brum, Patrícia Canazart Azzi et al.

The increasing demand for renewable energy solutions has driven research into cost-effective materials for photoelectrochemical hydrogen production. This study presents the synthesis and characterization of Cu2O thin films obtained via electrodeposition, aiming to optimize their structural, optical, and electronic properties for photocatalytic applications. UV-Vis spectroscopy revealed a direct bandgap of 2.0 eV, confirming the material's suitability for visible light absorption. Grazing Incidence X-ray Diffraction (GIXRD) analysis demonstrated that the films predominantly belong to the cubic crystal system, with a preferential (111) crystalline orientation. On the other hand, X-ray Photoelectron Spectroscopy (XPS), a surface-sensitive technique, indicated the coexistence of Cu2O and a minor proportion of CuO, likely resulting from surface oxidation. While bulk characterization confirmed that the core material remained Cu2O, the presence of hydroxides and carbonates in the surface suggests that optimizing deposition conditions or post-treatment processes could enhance stability and phase purity. These findings underscore the potential of Cu2O films as efficient photocathodes for hydrogen production. Future studies should focus on minimizing surface oxidation and integrating Cu2O-based electrodes into complete photoelectrochemical cells for sustainable energy applications.

Chungang Gu, Jiansheng Huang, Cathy A Muste et al.

BIIB104 (formerly PF-04958242), N-((3S,4S)-4-(4-(5-cyanothiophen-2-yl)phenoxy)tetrahydrofuran-3-yl)propane-2-sulfonamide, is an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor potentiator investigated for the treatment of cognitive impairment associated with schizophrenia. Preliminary in vitro metabolism studies with non-radiolabeled BIIB104 in rat, dog, and human liver microsomes (RLM, DLM, and HLM) showed O-dealkylation in all three species, tetrahydrofuran hydroxylation dominating in DLM and HLM, and thiophene hydroxylation prevalent in RLM. However, a subsequent rat mass balance study with [nitrile-14C]BIIB104 showed incomplete recovery of administered radioactivity (∼80%) from urine and feces over 7 days following an oral dose, and an exceptionally long plasma total radioactivity half-life. Radiochromatographic metabolite profiling and identification, including chemical derivation, revealed that [14C]cyanide was a major metabolite of [nitrile-14C]BIIB104 in RLM, but a minor and trace metabolite in DLM and HLM, respectively. Correspondingly in bile duct-cannulated rats, [14C]thiocyanate accounted for ∼53% of total radioactivity excreted over 48 hours postdose and it, as an endogenous substance, explained the exceptionally long plasma radioactivity half-life. The release of [14C]cyanide from the 2-cyanothiophene moiety is postulated to follow an epoxidation-initiated thiophene-opening based on the detection of non-radiolabeled counterpart metabolites in RLM. This unusual biotransformation serves as a lesson regarding placement of the radioactive label on an aryl nitrile when material will be used for evaluating the metabolism of a new drug candidate. Additionally, the potential cyanide metabolite of nitrile-containing drug molecules may be detected in liver microsomes with liquid chromatography–mass spectrometry following a chemical derivatization. SIGNIFICANCE STATEMENT Using [nitrile-14C]BIIB104, non-intuitive metabolites of BIIB104 were discovered involving a novel cyanide release from the 2-cyanothiophene motif via a postulated epoxidation-initiated thiophene-opening. This unusual biotransformation serves as a lesson regarding placement of the radioactive label on an aryl nitrile when material will be used for evaluating the metabolism of a new drug candidate.

Rui Liu, Jianjun Wan, Peng Zhang et al.

Thorium (Th) is a naturally occurring radioactive element found in the environment, and recent advancements have been made in identifying and characterizing Th-bearing nanoparticles (NPs). However, the main focus is still on synthesized Th-bearing NPs and knowledge about natural Th-bearing NPs remains limited. Here, high-resolution transmission electron microscopy (HRTEM) observations of thorite from the Huayangchuan uranium ore deposit in Shaanxi Province, Central China, have revealed the nanoscale mineral characteristics of thorite. In this study, thorite NPs ranging from 5-10 nm in size were identified within the uranium ore. A combination of transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS) elemental mapping and corresponding HRTEM images alongside Selected Area Electron Diffraction (SAED) and Fast Fourier Transform (FFT) patterns revealed a complex nanoscale structure in the thorite NPs, consisting of both amorphous and crystalline nanodomains with abundant defects. These nanostructures are associated with a metamictization mechanism in micrometer-sized thorite. Our findings indicate that the metamictization process can generate numerous thorite nanoparticles. Given the high penetrability and mobility of these NPs, the metamictization of thorite poses new challenges for the long-term stability of radioactive substances and the storage containers for radioactive waste. Furthermore, considering the likelihood of environmental release and the chemical toxicity, radioactivity, and nanotoxicity of natural Th-bearing NPs, increased attention should be given to the presence of natural thorite NPs in the ore deposit.

Pablo Andres, Astrid Bengtsson

Radiation risk perception must be studied by communication and radiological protection specialists, taking account of engineering, social and cultural variables. An anonymous and voluntary survey was peformed to enquire about the radiation risk perception among university students and radiological protection experts from Argentina, and to become aware of how it is perceived compared to other health risks. A fifteen-question dedicated questionnaire was designed including socio-demographic variables and questions about work environment, risk perception and risk communication. A five-point Likert-type scale was used for most of the questions. Surveyed people were asked to compare radiological risks in medicine with other risks (i.e.: smoking, sports, leisure activities, stress). The research involved 10 (38.5%) experts, 25 (45%) physics and engineering students and 40 (100%) bio-images production bachelor students. The results were analysed based on the professional or academic background. Although participants considered the radiation exposure in medicine as a low-risk activity, the results showed a disagreement about the radiation risk perception in particular situations (i.e.: living near a nuclear power plant, training in radiological protection while at college) and about radiation risk communication strategies. There is neither right nor wrong risk perception; however, a lot of work must be done to build an agreement between radiological risk perception and risk assessment due to radiation exposure in medicine. It should include working on the design of public policies focused on radiological protection training for health staff and clinical research training for medical physicists and radiological protection specialists, while strengthening communication skills and channels.

Sara Brambilla, Matthew A. Nelson, Michael J. Brown

Darren J. Koppel, Fenny Kho, Astley Hastings et al.

C. Touma, N. Sachser, E. Möstl et al.

Huaye Gao, Cheng Yang, Wenhui Hu et al.

BACKGROUND 101BHG-D01, a novel long-acting and selective muscarinic receptor antagonist for the treatment of chronic obstructive pulmonary disease (COPD), is undergoing Phase Ib clinical trial in patients and has shown its potential efficacy. Its preparation method and medical use thereof have been patented in the United States (Patent No.US9751875B2). OBJECTIVE In this study, the pharmacokinetics, mass balance, tissue distribution and metabolism of radioactive 101BHG-D01 were investigated in rats after an intravenous dose of 1 mg/kg [14C]101BHG-D01 (100 μCi/kg). METHODS Radioactivity in rat plasma, urine, feces, and tissues was measured by liquid scintillation counting (LSC), and metabolite profiling and identification were conducted by UHPLC-β-RAM and UHPLC-Q-Exactive Plus MS. RESULTS The total radioactivity of the study drug in rat plasma rapidly declined with an average terminal elimination half-life of 0.35 h. The radioactivity in most tissues reached the maximum concentration at 0.25 h post-- dosing. The radioactivity is mainly concentrated in the kidney and pancreas. The drug-related substances tended to be distributed into the blood cells in the circulation. At 168 h post dosing, the mean recovery of the total radioactivity in urine and feces was 78.82%. Fecal excretion was the major excretion route, accounting for approximately 61% of the radioactive dose. The study drug was metabolized extensively, and a total of 17 metabolites were identified in rat plasma, urine, and feces. The major metabolic pathways involved oxidation, oxidation and dehydrogenation, and O-dephenylation. CONCLUSION In conclusion, the study results are useful for better understanding the pharmacokinetic profiles of 101BHG-D01 and provide a robust foundation for subsequent clinical studies.

Farida Lolila, Mohamed Mazunga

In this study, pre-mining ambient gamma dose equivalent rates at 1 m above the ground were measured using a Gamma-Scout portable radiation survey meter at two sites, A and B, around the Manyoni uranium deposit in Tanzania. Site A is expected to receive mine-dust particles with an aerodynamic diameter ≤ 10 µm (PM10) that have mean annual ground level concentrations (AGLC) ≥ 10% of the WHO air quality guideline limit of 20 µg/m3, and Site B is expected to receive PM10 with a mean AGLC ≥ 20 µg/m3. At Site A, the average of the ambient dose equivalent rates was 0.25 ± 0.03 µSv/h and ranged from 0.08 to 0.69 µSv/h. Similarly, at Site B, the average of the ambient dose equivalent rates was 0.23 ± 0.02 µSv/h and ranged from 0.12 to 0.34 µSv/h. The effect of the local geology on the measured dose rates was also presented. Since the ambient dose equivalent is an operational quantity for area monitoring, the results of this study will be very useful for comparing with the operational monitoring results of Sites A and B once uranium mining starts in Manyoni. This can help mine operators and regulatory agencies keep an eye on any rise in background radiation so they can take the necessary measures to safeguard locals and the environment from the harmful effects of ionising radiation.

N.K.O. Barbosa, Lorena Sandoval Castillo, Juan Sebastián Quimbayo

Abstract Clinical uses of radiopharmaceuticals imply the administration of radioactive substances that are mainly excreted through urine. The Nuclear Medicine Department at the Instituto Nacional de Cancerología (INC-COL) in Bogota, Colombia, administers radiopharmaceuticals for diagnostics and treatment to many patients, resulting in tens of cubic meters of radioactive waste water (WW) every day. As Colombian regulatory limits for liquid radioactive discharges to the sewer system are lower than in other countries, longer WW decay times are required, even when an in-house waste water treatment plant (WWTP) is used. To fulfill the requirements for controlled disposal of radioactive discharges, a complementary abatement system was implemented to retain WW for periods as long as 360 d, and was connected to the hospital´s WWTP. These holding times can cause major changes in the WW physicochemical parameters, reaching levels higher than acceptable. In this study, we evaluate the decontamination and decay efficiency of the retention system using water quality parameters and the amount of radioactivity in the effluents stored in the tanks and the WWTP. According to the results, to maintain the physicochemical parameters below acceptable levels, biological and chemical treatment of decayed WW is necessary before discharging it into urban waste water. Using the principles of dilution, retention, and decay, an integral radioactive WW management system was implemented favoring the quality of discharges and activity levels to the sewer system, with efficiencies close to 100% for WW from discharges in diagnostic procedures ranging from 98% (131I) to 100% (177Lu) for WW from discharges in therapeutic procedures. Activity concentration assessment in medically-derived radionuclides using an in-house waste water treatment plant (WWTP) and a complementary abatement system; an in-house WWTP could be used as an abatement system for short-lived radionuclides; and a tank-based abatement system attached to the in-house WWTP showed higher efficiencies for long-lived radionuclides and adequate physicochemical parameters for the discharge to the city sewage system.

Jingchao Guo, Yaqi Sun, Yongxia Zhao et al.

Sulfamethoxazole (SMZ), as a sulfa antibiotic, is often used in the treatment of various infectious diseases in animal husbandry. At present, SMZ still has many unresolved problems in the material balance, metabolic pathways, and residual target tissues in food animals. Therefore, in order to solve these problems, the metabolism, distribution, and elimination of SMZ is investigated in pigs, chickens, and rats by radioactive tracing methods, and the residue marker and target tissue of SMZ in food animals were determined, providing a reliable basis for food safety. After a single administration of [3H]-SMZ (rats and pigs by intramuscular injection and chickens by oral gavage), the total radioactivity was rapidly excreted, with more than 93% of the dose excreted within 14 days in the three species. Pigs and rats had more than 75% of the administered volume recovered by urine. After 7 days of continuous administration, within the first 6 h, radioactivity was found in almost all tissues. The highest radioactivity and longest persistence in pigs was in the liver, while in chickens it was in the liver and kidneys, most of which was removed within 14 days. A total of six, three and three metabolites were found in chickens, rats and pigs, respectively. N4-acetyl-sulfamethoxazole (S1) was the main metabolite of SMZ in rats, pigs and chickens. The radioactive substance with the longest elimination half-life is sulfamethoxazole (S0), so S0 was suggested to be the marker residue in pigs and chickens.

Elena Yushkova

A.I. Kryshev, T.G. Sazykina, M.N. Katkova et al.

S. S. Silkin, L. Yu. Krestinina, A. V. Akleyev

The objective of the current study was to assess the cancer mortality risk in the cohort of the exposed population on the territory of the East Urals Radioactive Trace over a 57-year follow-up period from 1957 to 2014 using individual doses. Materials and methods: At the end of September 1957 as a result of an accident in the cooling system of storage tanks with liquid radioactive waste, an explosion occurred on the territory of the Mayak PA which led to the formation of the East Urals Radioactive Trace. The population living in the contaminated settlements of the Chelyabinsk and Sverdlovsk regions has been affected by prolonged external and internal exposure. The cohort of individuals exposed in the territory of the East Urals Radioactive Trace numbers 21,384 people, of whom 2,055 persons had lived in Techa riverside settlements before the 1957 accident and received additional radiation exposure. The mean stomach dose for members of the East Urals Radioactive Trace cohort was 36 mGy, the maximum dose was 1130 mGy. The updated TRDS-2016 dosimetry system was used to assess individualized doses. Over the 57-year follow-up period of the cohort (1957-2014), 1294 deaths from cancer were registered in the catchment area. The number of person-years at risk was 511278. The analysis of the cancer mortality risk was carried out with the EPICURE statistical package using the Poisson regression method. Confidence intervals were calculated using the maximum likelihood method. Results: In the course of the cancer mortality analysis in the East Urals Radioactive Trace cohort over a 57-year period, a statistically significant excess relative risk of mortality per 100 mGy equal to 0.05 (95% CI: 0.002; 0.11, p = 0.04) was obtained in the entire East Urals Radioactive Trace cohort. If individuals who received additional exposure on the Techa River were excluded from the analysis, the value of the risk loses its statistical significance.

angelica peixoto pinheiro

O câncer de colo do útero é um problema de saúde pública em todo o mundo e se inclui Norte do Estado do Tocantins como principal causa de morte por câncer na mulher. A falta de triagem eficaz aumenta a incidência de complicações tardias diagnóstico, pesando nos orçamentos dos países em desenvolvimento, que são osmais afetados. O objetivo do trabalho é descrever os aspectos epidemiológicosperfil de mulheres atendidas com diagnóstico de câncer de colo uterino no norte Tocantins. 2664 mulheres com câncer de colo de útero foram analisadas no Hospital Registro do Câncer (SIS-RHC), vinculado ao Hospital Regional de Araguaína (HRA). Houve predomínio de mulheres com idade entre 40 e 49 anos, de cor marrom, com ensino fundamental incompleto, casado e com umhistória do tabaco. O estágio predominante foi o IIIB com 31,8%, seguidopelo estágio 0 com 31,7%. Dentro dos estágios existentes: 0, I e II foram considerados“Estágios iniciais”, enquanto os estágios III e IV foram considerados “estágios finais”. Observou-se que 57,1% das mulheres apresentaram estadiamento precoce e 42,9% tardio encenação. Observou-se que pacientes com mais de 70 anos (56%), negros (66,2%), sem escolaridade (68,0%), relacionamento estável (54,3%) e ex-fumante (70,7%),foram aqueles com maiores porcentagens de atraso no estadiamento. A história da educação e tabagismo fatores foram bem envolvidos na incidência desse tumor, principalmente no estadiamento tardio.

S. V. Muminov, B. B. Barotov, M. M. Makhmudova et al.

The paper presents results of the radon survey carried out in preschool and school institutions in Dushanbe, Republic of Tajikistan. Radon concentration was measured using solid state nuclear track detectors Radtrak2. Track detectors were exposed for 3 months during the heating and warm seasons of the year in the same premises. In total, the measurements were performed in 200 premises of 14 kindergartens and 36 schools. The radon equilibrium equivalent concentration during the heating and warm seasons and the annual average radon equilibrium equivalent concentration were calculated. Annual average radon equilibrium equivalent concentration in surveyed buildings ranged from 42 to 331 Bq/m3 with the mean value of 98 Bq/m3 on the first floor and 56 Bq/m3 on the second floor. It was shown that both seasonal values and annual average value of radon equilibrium equivalent concentration in the premises on the second floor are lower than in the premises on the first floor. The annual average effective dose to children from exposure to radon and its progeny in the premises of schools and kindergartens in Dushanbe ranged from 0,64 to 1,64 mSv. The limit value of annual average radon equilibrium equivalent concentration in dwellings and public buildings is set to 100 Bq/m3 for newly built buildings and 200 Bq/m3 for existing buildings in the Radiation safety norms (NRB-06) of the Republic of Tajikistan. This limit was exceeded only on the first floors in one kindergarten during the heating season, in three schools during the warm season and in eight schools during the heating season. When comparing the results of measurements of radon equilibrium equivalent concentration with data on the geological structure of underlying rocks at the locations of the surveyed buildings, no regularity was found. Additional detailed measurements in the buildings, including basements, will help to identify the source of radon entry into the indoor air and to develop recommendations for implementing radon remediation actions separately for each building. The survey results were also used to develop a radon map of Dushanbe.

Valerii Kashparov, Brit Salbu, Sviatoslav Levchuk et al.

article Editorial

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A. M. Marennyy, S. M. Kiselev

The authors share their experience and represent the historical overview of activities on public radiation protection against radon and other natural sources of radiation in Russia. Special attention is paid to the country’s first national radon program - Federal Target Program “Radon” (FTP “Radon”, 1994-1996). Organization, structure, main goals and objectives of the FTP «Radon» are discussed. In particular, it was noted that in a short period of time the country’s regulatory and methodological framework was developed. The scientific basis for identification of the radon prone areas and regulatory support for building construction at the sites was developed. The national SSND equipment was produced and QA/QC system implemented. The national and regional radon surveys have been performed. Unfortunately, the economic situation of those years did not allow to fully implement the planned set of measures at the federal and regional levels. Nevertheless the accumulated experience served as a scientific and technical basis for further improvements in this field and to be consistent with the modern radon regulatory issues and approaches developed by the international organizations (ICRP, IAEA, WHO).