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1
Merešová, J., A. Belanová e M. Vršková. "Inter-laboratory comparison measurements of radiochemical laboratories in Slovakia". Applied Radiation and Isotopes 68, n. 7-8 (luglio 2010): 1282–85. http://dx.doi.org/10.1016/j.apradiso.2009.11.062.
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Leskinen, Anumaija, e Susanna Salminen-Paatero. "Development of 3H, 14C, 41Ca, 55Fe, 63Ni radiochemical analysis methods in activated concrete samples". Journal of Radioanalytical and Nuclear Chemistry 331, n. 1 (21 novembre 2021): 31–41. http://dx.doi.org/10.1007/s10967-021-08073-4.
Testo completoAbstract (sommario):
AbstractDevelopment of 3H, 14C, 41Ca, 55Fe and 63Ni radiochemical analysis methods were carried out independently by two laboratories using both inactivate and activated concrete samples. Two preliminary radioanalytical procedures for the non-volatile radionuclides (41Ca, 55Fe, 63Ni) and one Thermal oxidation method for the volatile radionuclides (3H, 14C) were developed. The difficulties in the method development and analysis of results are discussed.
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Salminen-Paatero, Susanna, Xiaolin Hou, Grzegorz Olszewski, Lina Ekerljung, Annika Tovedal, Anna Vesterlund, Angelica Andersson, Satu Kangas e Henrik Ramebäck. "Analyzing alpha emitting isotopes of Pu, Am and Cm from NPP water samples: an intercomparison of Nordic radiochemical laboratories". Journal of Radioanalytical and Nuclear Chemistry 329, n. 3 (28 luglio 2021): 1447–58. http://dx.doi.org/10.1007/s10967-021-07913-7.
Testo completoAbstract (sommario):
AbstractRadioanalytical methods for the determination of isotopes of Pu, Am and Cm in water samples from nuclear power plants were compared and further developed in a Nordic project (Optimethod) through two intercomparison exercises among Nordic laboratories. With this intercomparison, the analytical performance of some laboratories was improved by modification of the analytical method and adopting new techniques. The obtained results from the two intercomparisons for alpha emitting transuranium isotopes are presented, and the lessons learnt from these intercomparison exercises are discussed.
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Leskinen, Anumaija, Celine Gautier, Antti Räty, Tommi Kekki, Elodie Laporte, Margaux Giuliani, Jacques Bubendorff et al. "Intercomparison exercise on difficult to measure radionuclides in activated concrete—statistical analysis and comparison with activation calculations". Journal of Radioanalytical and Nuclear Chemistry 329, n. 2 (28 giugno 2021): 945–58. http://dx.doi.org/10.1007/s10967-021-07824-7.
Testo completoAbstract (sommario):
AbstractThis paper reports the results obtained in a Nordic Nuclear Safety Research project during the second intercomparison exercise for the determination of difficult to measure radionuclides in decommissioning waste. Eight laboratories participated by carrying out radiochemical analysis of 3H, 14C, 36Cl, 41Ca, 55Fe and 63Ni in an activated concrete. In addition, gamma emitters, namely 152Eu and 60Co, were analysed. The assigned values were derived from the submitted results according to ISO 13,528 standard and the performance assessments were determined using z scores. The measured results were compared with activation calculation result showing varying degree of comparability.
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Dollé, Frédéric, Sandrine Langle, Gaëlle Roger, Roger R. Fulton, Béatrice Lagnel-de Bruin, David J. Henderson, Françoise Hinnen et al. "Synthesis and In-Vivo Evaluation of [11C]p-PVP-MEMA as a PET Radioligand for Imaging Nicotinic Receptors". Australian Journal of Chemistry 61, n. 6 (2008): 438. http://dx.doi.org/10.1071/ch08083.
Testo completoAbstract (sommario):
Within the class of (4-pyridinyl)vinylpyridines developed by Abbott laboratories as potent neuronal nicotinic acetylcholine receptor ligands, p-PVP-MEMA ({(R)-2-[6-chloro-5-((E)-2-pyridin-4-ylvinyl)pyridin-3-yloxy]-1-methylethyl}methylamine) is the lead compound of a novel series that do not display the traditional nicotinic-like pyrrole-ring but still possessing high subnanomolar affinity (Ki 0.077 nm—displacement of [3H](–)cytisine from whole rat brain synaptic membranes). In the present study, p-PVP-MEMA and its nor-derivative ({(R)-2-[6-chloro-5-((E)-2-pyridin-4-ylvinyl)pyridin-3-yloxy]-1-methylethyl}methylamine) as precursor for labelling with the short-lived positron-emitter carbon-11 (T1/2 20.4 min) were synthesized in 10 chemical steps from 2-hydroxy-5-nitropyridine and Boc-d-alanine. N-Alkylation of nor-p-PVP-MEMA with [11C]methyl iodide afforded [11C]p-PVP-MEMA (>98% radiochemically pure, specific activity of 86.4 GBq μmol–1) in 2% (non-decay corrected and non-optimized) radiochemical yield, in 34 min (including HPLC purification and formulation). Preliminary positron emission tomography (PET) results obtained in a Papio hamadryas baboon showed that [11C]p-PVP-MEMA is not a suitable PET-radioligand.
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Al-Alawy, Iman Tarik, e Osamah Abdulameer Mzher. "Activity Measurement of Airborne Alpha and Beta Particles in Destroyed Radiochemical Laboratories, at Al-Tuwaitha-Iraq". Indian Journal of Public Health Research & Development 9, n. 12 (2018): 1222. http://dx.doi.org/10.5958/0976-5506.2018.02017.x.
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Uccelli, L., A. Boschi, M. Pasquali, A. Duatti, G. Di Domenico, G. Pupillo, J. Esposito, M. Giganti, A. Taibi e M. Gambaccini. "Influence of the Generator in-Growth Time on the Final Radiochemical Purity and Stability of Radiopharmaceuticals". Science and Technology of Nuclear Installations 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/379283.
Testo completoAbstract (sommario):
At Legnaro laboratories of the Italian National Institute for Nuclear Physics (INFN), a feasibility study has started since 2011 related to accelerated-based direct production of by the100Mo(p,2n) reaction. Both theoretical investigations and some recent preliminary irradiation tests on100Mo-enriched samples have pointed out that both the / ratio and the specific activity will be basically different in the final accelerator-produced Tc with respect to generator-produced one, which might affect the radiopharmaceutical procedures. The aim of this work was to evaluate the possible impact of different / isomeric ratios on the preparation of different Tc-labeled pharmaceutical kits. A set of measurements with , eluted from a standard99Mo/ generator, was performed, and results on both radiochemical purity and stability studies (following the standard quality control procedures) are reported for a set of widely used pharmaceuticals (i.e., -Sestamibi, -ECD, -MAG3, -DTPA, -MDP, -HMDP, -nanocolloids, and -DMSA). These pharmaceuticals have been all reconstituted with either the first [O4]−eluate obtained from a99Mo/ generator (coming from two different companies) or eluates after 24, 36, 48, and 72 hours from last elution. Results show that the radiochemical purity and stability of these radiopharmaceuticals were not affected up to the value of 11.84 for the / ratio.
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Rassou, Somasoudrame, Clarisse Mariet e Thomas Vercouter. "Analysis of radionuclides in microsystem: application to the selective recovery of 55Fe by solvent extraction". EPJ Nuclear Sciences & Technologies 6 (2020): 10. http://dx.doi.org/10.1051/epjn/2020002.
Testo completoAbstract (sommario):
The minimization of the sample quantities required by analytical laboratories, as well as the increase of the fastness of the analytical operations are emerging axes for improved radiochemical analyses related to D&D issues. Two microsystem-based protocols were developed for the selective recovery of 55Fe from radioactive samples by solvent extraction. Both protocols were tested on iron solutions in two different microchips. The yields of Fe extraction were compared with macroscale batch experiments. Better performances with more than 80% of iron extracted were obtained with the second protocol, which is based on a reactive transfer of the iron cation, and more suited to the use of microchannels and very low contact times. This study already demonstrate the high potential of microfluidic technology to improve analytical operations on D&D samples. This method will further be validated with radioactive samples.
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Churakov, Sergey V., Wolfgang Hummel e Maria Marques Fernandes. "Fundamental Research on Radiochemistry of Geological Nuclear Waste Disposal". CHIMIA International Journal for Chemistry 74, n. 12 (23 dicembre 2020): 1000–1009. http://dx.doi.org/10.2533/chimia.2020.1000.
Testo completoAbstract (sommario):
Currently, 5 · 1019 Bq of radioactive waste originating from the use of nuclear power for energy production, and medicine, industry and research, is maintained in Switzerland at intermediate storage facilities. Deep geological disposal of nuclear waste is considered as the most reliable and sustainable long-term solution worldwide. Alike the other European countries, the Swiss waste disposal concept embarks on the combination of engineered and geological barriers. The disposal cell is a complex geochemical system. The radionuclide mobility and consequently radiological impact depend not only on their chemical speciation but also on the background concentration of other stable nuclides and their behaviour in the natural environment. The safety assessment of the repository is thus a complex multidisciplinary problem requiring knowledge in chemical thermodynamics, structural chemistry, fluid dynamics, geo- and radiochemistry. Broad aspects of radionuclide thermodynamics and geochemistry are investigated in state-of-the-art radiochemical laboratories at the Paul Scherrer Institute. The research conducted over the last 30 years has resulted in a fundamental understanding of the radionuclides release, retention and transport mechanism in the repository system.
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Lima, Marisa de Jesus de C., Fabio Luiz Navarro Marques, Miriam Roseli Yoshie Okamoto, Alexandre Tales Garcez, Marcelo Tatit Sapienza e Carlos Alberto Buchpiguel. "Preparation and evaluation of modified composition for lyophilized kits of [Cu(MIBI)4]BF4 for [99mTc] technetium labeling". Brazilian Archives of Biology and Technology 48, spe2 (ottobre 2005): 1–8. http://dx.doi.org/10.1590/s1516-89132005000700001.
Testo completoAbstract (sommario):
The [Cu(MIBI)4]BF4 complex was synthesized and different formulations for lyophilized kits that could be cost-effectively used with different routines in nuclear medicine laboratories were investigated. In one preparation the kit components were kept similar to the Cardiolite® , except that the SnCl2.2H2O concentration was increased to 0.150 mg. In a second formulation, component concentrations were reduced to 1/5 of the original value and the SnCl2.2H2O concentration was adjusted to 0.04 mg. These products were labeled with maximum activities of 55.5 GBq and 8.14 GBq, respectively, and have shown an average radiochemical purity of 95 %. Biodistribution of the products was assessed by dissection in mice and in rabbits, and did not show any statistical difference when compared to Cardiolite®. In the synthesis of [Cu(MIBI)4]BF4 a new procedure was introduced for the synthesis of N-(2-methyl-propenyl)-formamide, with the use of microwave radiation as heat source. This modification reduced the reaction time to 25 seconds, while maintaining a yield of 68%.
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Otero-Pazos, Alberto, Alfonso Calleja-Garcia, Maria Fernandez-Ibanez, Benigno Rodriguez-Gomez, Andres Pinon-Pazos e Jose Calvo-Rolle. "Determination of Sr-90 in milk samples from the study of statistical results". Nuclear Technology and Radiation Protection 32, n. 2 (2017): 185–91. http://dx.doi.org/10.2298/ntrp1702185o.
Testo completoAbstract (sommario):
The determination of 90Sr in milk samples is the main objective of radiation monitoring laboratories because of its environmental importance. In this paper the concentration of activity of 39 milk samples was obtained through radiochemical separation based on selective retention of Sr in a cationic resin (Dowex 50WX8, 50-100 mesh) and subsequent determination by a low-level proportional gas counter. The results were checked by performing the measurement of the Sr concentration by using the flame atomic absorption spectroscopy technique, to finally obtain the mass of 90Sr. From the data obtained a statistical treatment was performed using linear regressions. A reliable estimate of the mass of 90Sr was obtained based on the gravimetric technique, and secondly, the counts per minute of the third measurement in the 90Sr and 90Y equilibrium, without having to perform the analysis. These estimates have been verified with 19 milk samples, obtaining overlapping results. The novelty of the manuscript is the possibility of determining the concentration of 90Sr in milk samples, without the need to perform the third measurement in the equilibrium.
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Vieth, Reinhold, Sarah E. Ledermann, Sang Whay Kooh e J. Williamson Balfe. "Losses of Calcitriol to Peritoneal Dialysis Bags and Tubing". Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 9, n. 4 (ottobre 1989): 277–80. http://dx.doi.org/10.1177/089686088900900409.
Testo completoAbstract (sommario):
Peritoneal dialysis provides a convenient means of administering calcitriol. We investigated in vitro the efficiency with which this approach would deliver the drug to patients. We used an injectable preparation of calcitriol, Calcijex® (Abbott Laboratories, Montreal, Quebec, Canada), which we radiolabelled by adding radioactive 1,25 dihydroxyvitamin D3 to it. The preparation was injected into dialysis bags and drained through appropriate tubing to monitor delivery of the radiolabelled calcitriol. By 2 h after injecting calcitriol into dialysis bags, 50% of the dose was left in the fluid, by 20 h only 26% was left. The delivered drug was pure 1,25-dihydroxyvitamin D3 based on chromatographic analysis of the recovered radiochemical. To study what would happen if the drug was in the bag for a minimal length of time the calcitriol was injected immediately prior to draining the fluid. We recovered 62.9% ± 5.2% SD of the dose from the tubing which would theoretically have entered a patient. There was no significant change in calcitriol dose delivered if the fluid was warmed to 37°C prior to injecting the drug and immediate drainage of the bag.
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Kochnov, Oleg Yu, Valery I. Stepanov, Denis A. Pakholik, Valery V. Kolesov e Evgeny V. Nikulin. "Experience in the production of 99Mo from low enriched uranium at the VVR-ts research nuclear facility". Nuclear Energy and Technology 10, n. 1 (26 marzo 2024): 15–18. http://dx.doi.org/10.3897/nucet.10.122284.
Testo completoAbstract (sommario):
The key industrial method for producing 99Mo is production of the radionuclide as one of the 235U fission fragments. 235U is irradiated with neutrons in a nuclear reactor (both heterogeneous and homogeneous nuclear reactors can be used) and then processed in radiochemical laboratories, where 99Mo is chemically extracted from fission products. Both highly enriched uranium (HEU) and low enriched uranium (LEU) can be used to produce 99Mo by the fragmentation method. To date, almost all world producers, with the exception of Russia, are either in the final stages of transferring production from highly enriched uranium to low enriched uranium, or are already producing 99Mo using LEU. This is due to the problems of non-proliferation of nuclear materials and the prevention of the likelihood of terrorist threats. A number of experimental studies have been carried out on the basis of the VVR-ts research reactor. Experimental studies included the study of the effect of LEU targets on the reactivity reserve of the VVR-ts reactor, irradiation of these targets in experimental channels and separation of 99Mo from them. The paper presents the results of producing and separating 99Mo from targets with LEU material. It is shown that it is necessary to improve the processing technology to increase the production of fragmented 99Mo from LEU.
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Camacho, Ximena, Agustina Banchero, Maria Fernanda García, Marcelo Fernández, Natalia Oddone, María Moreno, Cecilia Guillermo, Juan Pablo Gambini, Pablo Cabral e Eloísa Riva. "99m. Tc-Rituximab as Radiotracer For Molecular Imaging In Non Hodgkin Lymphoma". Blood 122, n. 21 (15 novembre 2013): 3026. http://dx.doi.org/10.1182/blood.v122.21.3026.3026.
Testo completoAbstract (sommario):
Abstract Introduction Non-Hodgkin lymphoma (NHL) is the most common hematologic malignancy and the fifth leading cause of cancer death in the world; over 90% are B cell lymphomas and express CD-20 surface antigen [1]. CD-20 antigen is a transmembrane protein of 33-37 kDa protein located on the surface of pre-B and mature lymphocytes B [2, 3]. It is expressed in 90% of B-cell NHL [4]. Anti-CD20 antibody (Rituximab®), a specific chimeric monoclonal antibody directed against CD20 on B lymphocytes and the first monoclonal antibody approved for the treatment of CD20+ NHL. The development of new agents directed against specific targets may improve the sensitivity and specificity of imaging for its staging. Objective To radiolabel Rituximab with 99mTc and evaluate its properties as a potential imaging agent for NHL. Methodology Rituximab was derivatized with succinimidyl-hydrazinonicotinamide (Suc-HYNIC) and MALDI TOF/TOF was used to confirm the level of HYNIC conjugation to Rituximab. This antibody was radiolabeled with 99mTc using a mixture of Tricine/SnCl2.2H2O. Radiochemical purity was determined by ITLC-SG, size exclusion chromatography and HPLC. In-vitro stability was studied in solution; serum and L-Cysteine up to 24 h. In-vitro binding and competition assays were performed with Ramos and Raji NHL cell lines up to 120 min and were analyzed by laser confocal microscopy. Ramos and Raji cells were incubated with buffer to evaluate any degree of autofluorescence. Biodistribution studies were performed in normal Balb/C mice at 1, 4, 24 and 48 h (n = 5). Results HYNIC- Rituximab was efficiently labeled with 99mTc. The in-vitro radiochemical stability studies of the radiolabeled antibody showed that the complexes formed were stable and no significant transchelation was detected. In-vitro binding and displacement assays confirm that after derivatization and labeling, Rituximab retained its specificity of binding to CD-20 antigen. Immunoreactivity of HYNIC-Rituximab to Ramos and Raji cell lines was determined by direct immunofluorescence. We observed a remarkable cell membrane staining of the NHL cells. Nuclei were counterstained with 4',6-diamidino-2-phenylindole (DAPI). After its incubation with buffer, auto fluorescence was discarded. These results show that Rituximab´s affinity for NHL cells remained unaffected after its derivatization. Biodistribution studies were performed to quantify localization and clearance of the radiolabeled antibody complex in normal tissues. Significant accumulation of radioactivity was found in liver, indicating that the primary route of clearance was hepatic. Other major uptake was not found after evaluating the rest of the organs at the observed time points. Conclusions 99mTc-HYNIC-Tocilizumab was easily and rapidly labeled, with radiochemical purities greater than 90%, retaining its specificity of binding. Our results indicate that 99mTc-HYNIC-Rituximab represents a promising molecular imaging agent for NHL. Acknowledgments ANII, Roche Laboratories, Pro.In.Bio. PEDECIBA Química References [1] Swerdlow AJ. Epidemiology of Hodgkin’s disease and nonHodgkin’s lymphoma. Eur J Nucl Med Mol Imaging 2003; 30 Suppl 1:S2–12. [2] Einfield DA, Beown JP, Valentine MA, et al. Molecular cloning of the human cell CD20 receptor predicts a hydrophobic protein with multiple transmembrane domains. EMBO J 1988; 7, 711-717. [3] Valentine MA, Meier KE, Rossie S, et al. Phosphotylation of the CD20 phosphoprotein in resting B lymphocytes. Regulation by protein kinase. C J Biol Chem 1989; 264, 11282-11287. [4] Tedder TF, Boyd AW, Freedman As, et al. The B cell surface molecule B1 is functionally linked withBcell activation and differentiation. J Immunol 1985; 135, 973-979. Disclosures: No relevant conflicts of interest to declare.
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LaRosa, J. J., E. L. Cooper, A. Ghods-Esphahani, V. Jansta, M. Makarewicz, S. Shawky e N. Vajda. "Radiochemical methods used by the IAEA's laboratories at Seibersdorf for the determination of 90Sr, 144Ce and Pu radionuclides in environmental samples collected for the International Chernobyl project". Journal of Environmental Radioactivity 17, n. 2-3 (gennaio 1992): 183–209. http://dx.doi.org/10.1016/0265-931x(92)90025-o.
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Bennett, J., C. J. Webb e S. Isch. "Preparing a laboratory for radioanalytical emergency response". Proceedings in Radiochemistry 1, n. 1 (1 settembre 2011): 201–7. http://dx.doi.org/10.1524/rcpr.2011.0036.
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AbstractAs the state of the nation's ability to respond to a radiological event is examined, it has become apparent that both capacity and capability are lacking. Department of Homeland Security National Planning Scenario #11 is designed to address the planning activities for the response to an attack using radiological dispersal devices. The scenario details show that the cleanup activity will take several years, and that there will be between 360000 and 1000000 environmental samples in the first year. Based on existing capacity and capabilities it would take four to six years to analyze the samples generated at the lower end of the sample range.The Environmental Protection Agency (EPA) has been given responsibility for the remediation activities following a radiological event, and has awarded cooperative agreements to several laboratories to start the process of developing capacity and capabilities. The Connecticut Department of Public Health Laboratory (DPHL) was awarded one of the cooperative agreements. The DPHL has started activities to further those goals by investigating and implementing procedures to ensure that samples with activity higher than normal background can be processed safely, as well as implementing more rapid methods for radiochemical analysis. The DPHL already served as the primacy radiochemistry laboratory for several New England states and thus had a solid foundation to build upon. The DPHL has taken a process flow approach in preparing for radiological emergency response and recommends that radioanalytical laboratories that are reviewing their roles in such a response: • Ensure that their Nuclear Regulatory Commission licenses allow for appropriate radioisotope types and activities;• Develop procedures and processes to ensure that samples with higher activities can be processed safely, with due regard for sample screening and aliquanting samples;• Provide for enhanced radioanalytical contamination control, with careful consideration of sample flow and breaking the laboratory into zones with controlled access;• Address personnel safety by enhancing training, adding real time dosimetry to exposure monitoring protocols, and reviewing personal protective equipment and hygiene protocols with staff;• Develop plans for spills and decontamination, as well as for increased monitoring of laboratory areas;• Plan for secure sample storage;• Exercise the plan.
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Robinson, Sharon M., Dennis E. Benker, Emory D. Collins, Julie G. Ezold, Jon R. Garrison e Susan L. Hogle. "Production of Cf-252 and other transplutonium isotopes at Oak Ridge National Laboratory". Radiochimica Acta 108, n. 9 (25 settembre 2020): 737–46. http://dx.doi.org/10.1515/ract-2020-0008.
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AbstractIn 1957 Glenn T. Seaborg conceived and advocated for the construction of the High Flux Isotope Reactor (HFIR) and the Transuranium Processing Plant (since then renamed the Radiochemical Engineering Development Center, or REDC) at Oak Ridge National Laboratory. Heavily shielded hot cells, glove boxes, and laboratories allow recovery of transuranium elements produced in substantial quantities. Seaborg’s vision of HFIR and REDC producing milligram quantities of berkelium, californium, and einsteinium has been fulfilled beginning in 1966 through May 2019 with 78 production campaigns yielding a cumulative totals of 1.2 g of 249Bk, 10.2 g of 252Cf, 39 mg of 253Es, and 15 pg of 257Fm. Notably, 252Cf is a neutron source used in many industrial applications including oil exploration; process control systems for the cement industry, coal analysis, and power production; sources to start nuclear reactors and perform nondestructive materials analyses; homeland security and national defense detection devices; and medical research. Isotopes made available through transplutonium production at HFIR/REDC have enabled scientists to study the nuclear properties and reactions, chemical properties, optical properties, and solid-state properties of transplutonium elements. Long-lived isotopes have served as targets in heavy ion accelerators to produce heavier elements leading to the discovery of 104Rf, 105Db, 106Sg, 113Nh, 114Fl, 115Mc, 116Lv, 117Ts, and 118Og. This paper reviews the evolution of the processing flowsheets to produce, separate, and purify transplutonium isotopes, which have evolved over 50 years of operation at HFIR and REDC, and summarizes directions of future work to improve the efficiency of the production operations.
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Pivovarov, A. A., E. A. Pivovarova e V. E. Kurganov. "About development of control levels of specific total alpha-activity in water samples for a number of sources of the centralized economic and drinking water supply in the Republic of Khakassia". Radiatsionnaya Gygiena = Radiation Hygiene 12, n. 2(св) (23 settembre 2019): 121–28. http://dx.doi.org/10.21514/1998-426x-2019-12-2s-121-128.
Testo completoAbstract (sommario):
The aim of the work is to develop control levels of specific total alpha-activity of water samples for a number of sources of centralized drinking water supply in the Republic of Khakassia on the basis of the results of long-term laboratory studies. Materials and methods. The analysis is carried out on the basis of the results of laboratory studies of water sources of centralized drinking water supply of the population of the Republic of Khakassia, performed by accredited testing laboratories of institutions of the state sanitary and epidemiological service of the Republic for the period from 2001 to 2018, using alpha-beta radiometric, alpha-spectrometric methods with radiochemical preparation of counting samples, gamma-spectrometric method. The control levels of specific total alpha-activity of water samples from the sources of centralized drinking water supply in the Republic of Khakassia were established by the statistical maximum – the sum of the average value with a doubled standard deviation, with the volume of research more than 30, and the maximum value with the volume of research less than 30. Results. About half of the studied water samples from the sources of the centralized drinking water supply of the Republic of Khakassia, annually, are noted with exceeding the control level of specific total alpha-activity (0,2 Bq/kg). The values obtained in the studied samples vary up to 5,57 Bq/kg. During the observation period, samples of water exceeding the reference level of specific total alpha-activity (0.2 Bq/kg) were identified in settlements of the Altai, Askizsky, Beysky, Bogradsky, Ordzhonikidzevsky, Tashtypsky, Ust–Abakansky, Shira districts and the city of Sorsk, smt. Prigorsk (Chernogorsk). In previous studies, it was found that high levels of specific total alpha-activity in the country are mainly due to natural radionuclides uranium-238 (238U), uranium-234 (234U). In a number of settlements of the Republic, the sum of the ratio of specific activities of natural radionuclides to the corresponding levels of intervention exceeds 1,0. Average annual individual effective doses of internal exposure to natural radionuclides of drinking water, at or above 0,1 mSv/year (values in the range of 0,1-0,2 mSv/year), which does not require urgent radiation protection measures. At the same time, monitoring of indicators of radiation safety of water sources of water supply should be carried out in accordance with the established requirements. In this connection, in order to improve control, for the rapid assessment of the radiation situation and making timely decisions to ensure radiation safety of the population, the calculation of control levels of specific total alpha-activity was carried out. As a result of calculations, specific values of control levels for each of water source were obtained. The calculated values range from 0,2 to 2,6 Bq/kg. Conclusion. The control levels are “site standards” and are calculated for each of the source of water supply. Their excess will be considered as a signal of “negative change” of the radiation situation”, which may be associated with an increase of the specific activities of 234U, 238U, or the appearance of highly radiotoxic radionuclides: 226Ra, 210Po, 228Ra.
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Riva, Eloísa, Victoria Calzada, Eugenia Gutiérrez, Marcelo Fernández, Natalia Oddone, María Moreno, Juan Benech, José A. Chabalgoity, Atanasio Pandiella e Pablo Cabral. "Development of 99mTcHYNIC-Tocilizumab as Imaging Agent In Multiple Myeloma". Blood 116, n. 21 (19 novembre 2010): 4081. http://dx.doi.org/10.1182/blood.v116.21.4081.4081.
Testo completoAbstract (sommario):
Abstract Abstract 4081 Introduction: Multiple myeloma (MM) accounts for 10% of hematological malignancies and 1% of cancer. It represents the second most common hematologic malignancy. The disease is characterised by plasma cell infiltration of the bone marrow, osteolytic bone lesions and the presence of a monoclonal paraprotein in the serum or urine. Interleukin-6 (IL-6) is a key molecule in the pathogenesis of MM. Its secretion occurs from the tumoral plasma cell as well as from the microenvironment. This results in myeloma cell proliferation. Tocilizumab, a humanized anti IL-6 receptor monoclonal antibody that blocks IL-6 cell-to-cell signaling, is currently being studied in MM. Most MM patients experience bone lesions. In spite of the new imaging techniques, the distinction between malignant and benign lesions remains sometimes difficult in clinical practice. The development of a more specific imaging agent may improve the accuracy of this diagnosis. Objective: Development of 99mTcHYNIC-Tocilizumab conjugate. Chemical and biological evaluation as a potential imaging agent in multiple myeloma. Methodology: 10 mg Tocilizumab (Roche) were added to 20 mg HYNIC in NaHCO3 1M, incubated for 30 min at room temperature and purified by means of PD10 column. 1 ml fractions were measured at 280nm. Conjugation of HYNIC-Tocilizumab was evaluated by mass spectrometry MALDITOF and acrylamide gel electrophoresis. 20 uL Tricine/stannous chloride in a 1:1 mass relation were added to 1 mg HYNIC-Tocilizumab in 100 uL of 0.9% NaCl. 2 mL of a solution containing 370 MBq 99mTcO4- was added. Radiochemical purity was controlled by three chromatographic systems: ITLC/NaCl 0.9%, Whatman 1MM/MEK, ITLC in BSA/EtOH-NH3-H2O (2:1:5) as stationary and mobile phase, respectively. Binding to IL-6 receptor in U266 myeloma cells was evaluated in vitro at 15, 30, 60 and 120 min. Tocilizumab was derivatized with FTIC and purified by PD10 column. Laser scanning confocal microscopy was done with an excitation/emission wavelength of 488/530 nm. Fluorescent images were obtained. Biodistribution studies were performed at 24 h in CD1 normal mice (n=3). Each mice was injected with 37 MBq of 99mTcHYNIC-Tocilizumab and sacrificed 24 hs after injection. Organs of interest were collected. Results: Mass spectroscopy MALDITOF (MH+Tocilizumab 147626 Da, M+HYNIC-Tocilizumab 148375 Da) confirmed derivatization of the antibody. This represents 5 molecules of HYNIC per molecule of the antibody. Poliacrylamide gel electrophoresis confirmed that the antibody retained its integrity after derivatization. Radiochemical purity was 88±3 %. In vitro cell binding assays confirmed the binding ability of the radiolabeled antibody to IL-6 receptor. Specificity of binding was supported by competition experiments using unlabelled antibody. Confocal microscopy proved the ability of the fluorescent antibody to recognize the IL-6 receptor in U266 myeloma cells. Biodistribution at 24 h showed blood (8.0±2.0) %act/g, liver (11±1.5) %act/g, kidney (4.0±1.0)%act/g and spleen (6±1.4) %act/g uptake with hepatic and renal elimination. Animal models of MM are being evaluated using xenografted MM cells. Conclusion: 99mTcHYNIC-Tocilizumab labeling was performed. The labeled antibody retained adequate biochemical and biological properties, which included maintenance of specific binding to IL-6 receptor. These findings indicate that this radiolabeled antibody could be used as an imaging agent in multiple myeloma. Acknowledgments: OIEA, Laboratorios Roche, Dr Gustavo Arroyo. Disclosures: No relevant conflicts of interest to declare.
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Smith, Gary L., e Steven C. Marschman. "Nuclear Waste Analytical Round Robins 1-6 Summary Report". MRS Proceedings 333 (1993). http://dx.doi.org/10.1557/proc-333-461.
Testo completoAbstract (sommario):
ABSTRACTThe Materials Characterization Center (MCC) at Pacific Northwest Laboratory(a) conducts Nuclear Waste Analytical Round Robins on simulated waste glasses with and without radionuclides. The analytical round robins are used to provide analytical laboratories with a forum for improving the accuracy and precision of analytical techniques that will be used for characterizing nuclear waste glasses. Chemical analysis data on glass waste forms produced by the nuclear waste community may need to withstand legal challenges for waste material storage qualification and for licensing repositories. Determining the quality of analytical data is important for meeting these challenges, making process operation decisions, and predicting long-term waste behavior.The MCC has conducted six round robins for the waste management, research, and development community from 1987 to the present time. The laboratories that have participated regularly are Ames, Argonne, Catholic University, Lawrence Livermore, Pacific Northwest Laboratory, Savannah River, and West Valley Nuclear. The glass types analyzed in these round robins all have been simulated nuclear waste compositions expected from the vitrification of high-level nuclear waste. A wide range of analytical procedures have been used by the participating laboratories, including Atomic Absorption spectroscopy, inductively coupled plasma-atomic emission spectro-scopy, direct current plasma-emission spectroscopy, and inductively coupled plasma-mass spectroscopy techniques. The consensus average relative error for Round Robins 1 through 6 is 5.4%, with values ranging from 9.4 to 1.1%. The trend on the average improved with each round robin. When the laboratories analyzed samples over longer periods of time, the intralaboratory variability increased. Lab-to-lab variation accounts for most of the total variability found in all the round robins. To date, participation in the radiochemistry portion has been minimal and the analytical results poor when compared to the nonradiochemistry portion of the round robins. Additional radiochemical work is needed in future round robins.
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Leskinen, Anumaija, Eric Dorval, Emilie Baudat, Celine Gautier, Solveig Stordal e Susanna Salminen-Paatero. "Intercomparison exercise on difficult to measure radionuclides in spent ion exchange resin". Journal of Radioanalytical and Nuclear Chemistry, 10 dicembre 2022. http://dx.doi.org/10.1007/s10967-022-08687-2.
Testo completoAbstract (sommario):
AbstractA need for method validation in radiochemical analyses of decommissioning waste is a challenging task due to lack of commercial reference materials. Participation in an intercomparison exercise is one way for a laboratory to assess their performance and validate their analysis results. A three-year project within the Nordic Nuclear Safety Research (NKS) community was initiated in order to carry out intercomparison exercises on difficult to measure (DTM) radionuclides in real decommissioning waste. Both Nordic and Non-Nordic laboratories participated. This paper reports the results from the final year of the project focusing on beta- and gamma emitter (i.e., easy to measure, ETM) analysis in spent ion exchange resin. The assigned values were derived from the participants’ results according to ISO 13528 standard and the performances were assessed using z scores. The results showed generally good performances for both DTMs and ETMs.
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Infantino, Angelo, Richard William Harbron, Renaud Mouret, Philippe Bertreix, Ana-Paula Bernardes, Luca Bruno, Marco Calviani et al. "Radiological characterization for the disposal of a decommissioned LHC external beam dump at CERN". European Physical Journal Plus 138, n. 8 (8 agosto 2023). http://dx.doi.org/10.1140/epjp/s13360-023-04319-0.
Testo completoAbstract (sommario):
AbstractDuring the last Long Shutdown, a scheduled maintenance period between physics runs, the two Large Hadron Collider (LHC) beam dumps were replaced with upgraded spares modules. It was then decided to conduct an in-house autopsy and a post-irradiation examination of the removed dumps to extract information essential for the 3rd LHC physics run and to aid the design of new generations of beam dumps able to cope with future upgrades of the LHC. The need for a postmortem analysis of the dump cores opened the opportunity to combine the autopsy with processes required for the disposal of the dumps as radioactive waste at a dedicated disposal facility in France. This had a direct impact in terms of overall optimization of the interventions (postmortem analysis and prepackaging) to be performed on the dump as well as in terms of minimizing of the radiological risk (ALARA), by reducing the exposure of the personnel by combining two interventions in one. The characterization of the dump as radioactive waste was performed by means of state-of-the-art Monte Carlo and analytical techniques verified experimentally via a series of dedicated radiochemical (using liquid scintillation) analyses, conducted in-house and in external specialized laboratories. Based on these results, the dumps will be disposed of as intermediate–medium-level (FMA-VC) waste at the ANDRA CSA repository in France.
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Woidy, Patrick, e Oliver Meisenberg. "Production of sealed rod sources made from epoxy resin for the Saint-Petersburg brick phantom for the calibration of whole-body counters". Radiation and Environmental Biophysics, 14 luglio 2022. http://dx.doi.org/10.1007/s00411-022-00987-1.
Testo completoAbstract (sommario):
AbstractRod sources are a common tool for the calibration of whole-body counters in combination with the Saint-Petersburg brick phantom. Here, a method for the production of such sources in ordinary radiochemical laboratories is presented. The rod sources consist of a tubular capsule of rigid polyvinyl chloride with a radioactive filling of epoxy resin. The method allows the production of rod sources at material costs of about 1 € per rod source and of ten rod sources by one person per day. Quality-assurance measurements were performed regarding the spatial distribution of the activity within the rod sources and the distribution of the activity throughout a set of sources. The relative double standard deviation of the activities of five different segments of single rod sources was 7.1%. The relative double standard deviation within a set of 90 rod sources was 2.8% after those 11% of sources with the greatest deviation from the arithmetic mean were discarded. Tests according to ISO 2919 to certify the rod sources as sealed sources of Class 2 of this standard were successfully conducted. The bending test proved to be the most critical test for the rod sources; the sources were broken by a mass of 12–14 kg, which is only slightly more than the stipulated mass of 10.2 kg. The presented method allows for a cost- and labour-effective production of sealed radioactive rod sources and thus facilitates the application of the Saint-Petersburg brick phantom for calibrations and interlaboratory comparisons of whole-body counters.