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This work describes the development and optimization of the radiochemical separation of 147Pm and 151Sm. The two main challenges addressed were: the radiochemical separation of the lanthanides by using LN Resin and DGA,N Resin, and the quantification of the chemical recovery of 147Pm with a non-isotopic analogue (i.e. neodymium). The applicability of radiochemical separation procedures was investigated by using spiked samples. The optimized radiochemical separation procedure by using LN Resin was applied to a reactor cooling water primary coolant sample with an automated system. Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) was used to determine the chemical recoveries. [ABSTRACT FROM AUTHOR]

During the optimization of 36Cl determination in solid wastes from nuclear decommissioning, a residual 36Cl signal was observed in procedural blanks measured after processing active samples. To uncover the possible causes, we investigated the interaction of chlorine with the components of a Pyrolyser-6 Trio™, as well as the chemicals used during the procedure. Different treatments for identifying the source of chlorine carryover were thoroughly investigated, demonstrating that the 36Cl memory effect arises from the interaction with pyrolyser components and that it occurs almost every time when the analysis procedure is performed. Therefore, results obtained using this analysis procedure need to be corrected for this memory effect by measuring procedural blank samples before and after measuring 36Cl-containing samples. [ABSTRACT FROM AUTHOR]

A method is presented for calculating the expected number of counts in peaks that have a large relative peak-area uncertainty and appear in measured gamma-ray spectra. The method was applied to calculations of the correction factors for peaks occurring in the spectra of radon daughters. It was shown that the factors used for correcting the calculated peak areas to their expected values decrease with an increasing relative peak-area uncertainty. The accuracy of taking the systematic influence inducing the correction factors into account is given by the dispersion of the correction factors corresponding to specific peaks. It was shown that the highest accuracy is obtained in the peak analyses with the GammaVision and Gamma-W software. [ABSTRACT FROM AUTHOR]

A study on the use of 3M Empore™ Radium RAD disk for the rapid and direct determination of Ra and Ra concentration in drinking water samples by means of liquid scintillation spectrometry is described. Three cocktails and several treatments were tested in order to improve the knowledge on the energy transfer between the alpha or beta-particle emissions of the isotopes fixed in the RAD disk and the cocktail. The sources of variability of this method were compared with the elution method, in which radium is stripped from de RAD disk and measured by liquid scintillation spectrometry using a Quantulus 1220™. [ABSTRACT FROM AUTHOR]

Physical phantoms are used at whole-body-counting (WBC) laboratories to calibrate detector systems for in vivo monitoring of radionuclides internally deposited in the body. Such phantoms should realistically represent the human body in the selected measurement geometry. In the past, the bottle manikin absorption phantom was used for calibration purposes at the laboratory for Anthropogammametry of SCK•CEN (American National Standard Institute. Specifications for the bottle manikin absorption phantom. ANSI/HPS N13.35, 1999). However, it was considered inadequate because of the leakage risk and the volume of radioactive waste produced at each calibration. As a consequence of this fact, a new phantom was developed. The Emma phantom is made of Epramid blocks (cylinders, cuboids and elliptical cylinders) in which sealed line sources can be introduced. The phantom is modular; so different body geometries can be made. This paper presents the phantom with its sources. The phantom was used to calibrate the SCK•CEN WBC setup. Efficiency calibration curves were obtained for different body geometries. The results of the calibration are discussed. [ABSTRACT FROM PUBLISHER]

A recent study on trace elements in beauty products and cosmetics sold on the Asian market has shown the presence of high levels of U, Th and rare earth elements in so called “Hormesis cosmetics.” For the purpose of comparison, some more information about trace elements in European cosmetics would be useful. In this paper the results obtained using k0-standardised Instrumental Neutron Activation Analysis ( k0-INAA) for more than 20 trace elements in 20 different beauty products collected from the European market are presented. We found traces of Ba, As and Sb which is in breach with European legislation. For some of the other elements like Cr and Co further speciation is needed in order to evaluate their presence in beauty products. [ABSTRACT FROM AUTHOR]

Several recent intercomparisons and certification exercises have shown that the determination of tin in e.g. food samples and plastics is not straightforward. k0-Instrumental Neutron Activation Analysis ( k0-INAA) offers some intrinsic quality control opportunities for the determination of the tin content in samples since several monitoring radioisotopes are formed. In this work we will discuss the validation of the determination of tin by k0-INAA using different reference materials. The results show that only few of these radioisotopes are reliable in terms of accuracy and that from a survey of the tin content in a range of canned foods detection limits as low as 2 mg/kg can be achieved. [ABSTRACT FROM AUTHOR]

Shoulder pathology consistent with osteochondritis dissecans of the humeral head was diagnosed in two small-breed dogs. In both cases, the diagnosis was made tentatively on the basis of radiography and confirmed by arthroscopy of the affected shoulder joint. Both dogs were successfully treated by surgical removal of a flap of cartilage from the affected area. Clinical and radiographic follow-up was available in both cases. The excised cartilage flaps were examined histopathologically and showed the same characteristics as cartilage flaps from dogs of large breeds prone to developing osteochondritis dissecans of the shoulder. [ABSTRACT FROM AUTHOR]

Shortly after an atmospheric release, the interception of radionuclides by crop canopies represents the main uptake pathway leading to food chain contamination. The food chain models currently used in European emergency decision support systems require a large number of input parameters, which inevitably leads to high model complexity. In this study, we have established a new relationship for wet deposited radionuclides to simplify the current modelling approaches. This relationship is based on the hypothesis that the stage of plant development is the key factor governing the interception of radionuclides by crops having horizontally oriented leaves (planophile crops). The interception fraction (f) and the leaf area index normalized (f LAI) and mass normalized (f B) interception fractions were assessed for spinach (Spinacia oleracea) and radish (Raphanus sativus) at different stages of plant development and for different contamination treatments and plant densities. A database of 191 f values for Cs-137 and Th-229 was built and complemented with existing literature covering various radionuclides and crops with similar canopy structure. The overall f increased with the plant growth, while the reverse was observed for f B. The f LAI significantly decreased by doubling the contaminated rainfall deposited. Fitting a multiple linear regression to predict the f value as a function of the standing biomass (B), and the radionuclide form (anion and cation) led to a better estimation of the interception (R2 = 81%) than the ECOSYS-87 model (R2 = 35%). Hence, the simplified modelling approach here proposed seems to be a suitable risk assessment tool as fewer parameters will minimize the model complexity and facilitate the decision-making procedures in case of emergencies, when countermeasures need to be identified and implemented promptly. Image 1 • The wet deposition of Cs-137 and Th-229 was experimentally simulated. • Radionuclide interception by planophile crops is mainly affected by plant biomass and radionuclide electrical charge. • An allometric relationship between leaf area index LAI and biomass B as well as interception fraction f and B was found. • A new semi-empirical relationship for the estimation of radionuclide interception by agricultural crops was established. • A simple approach for decision support systems was proposed. A simplified approach was proposed to assess the wet interception of trace elements by agricultural crops characterized by horizontally oriented leaves: key factors are the crop biomass and the radionuclide electrical charge. [ABSTRACT FROM AUTHOR]

The implementation of the one-pass-through separation technique using two stacked chromatography columns of TEVA – TRU resins for the separation of 237 Np, 241 Am, thorium, plutonium and uranium from environmental and urine samples was investigated. The sequential separation technique proved to be successful and gave similar results to those obtained when using individual separations. The analysis time was considerably improved. The amount of chemical waste was also reduced by 50% and the use of HClO 4 was avoided. The technique of ICP-MS was also investigated as a complementary technique to alpha-spectrometry. [ABSTRACT FROM AUTHOR]

Some authors have raised doubt about the invariability of decay constants, which would invalidate the exponential-decay law and the foundation on which the common measurement system for radioactivity is based. Claims were made about a new interaction – the fifth force – by which neutrinos could affect decay constants, thus predicting changes in decay rates in correlation with the variations of the solar neutrino flux. Their argument is based on the observation of permille-sized annual modulations in particular decay rate measurements, as well as transient oscillations at frequencies near 11 year −1 and 12.7 year −1 which they speculatively associate with dynamics of the solar interior. In this work, 12 data sets of precise long-term decay rate measurements have been investigated for the presence of systematic modulations at frequencies between 0.08 and 20 year −1 . Besides small annual effects, no common oscillations could be observed among α, β - , β + or EC decaying nuclides. The amplitudes of fitted oscillations to residuals from exponential decay do not exceed 3 times their standard uncertainty, which varies from 0.00023 % to 0.023 %. This contradicts the assertion that 'neutrino-induced' beta decay provides information about the deep solar interior. [ABSTRACT FROM AUTHOR]

Nowadays, there is interest in developing gamma-ray measuring devices based on the room temperature operated medium resolution detectors such as semiconductor detectors of the CdZnTe type and scintillators of the LaBr3 type. This is true also for safeguards applications and the International Atomic Energy Agency (IAEA) has launched a project devoted to the assessment of medium resolution gamma-ray spectroscopy for the verification of the isotopic composition of U and Pu bearing samples. This project is carried out within the Non-Destructive Assay Working Group of the European Safeguards Research and Development Association (ESARDA). In this study we analyze medium resolution spectra of U and Pu standards with the aim to develop an isotopic composition determination algorithm, particularly suited for these types of detectors. We show how the peak shape of a CdZnTe detector is influenced by the instrumentation parameters. The experimental setup consisted of a 500 mm3 CdZnTe detector, a 2×2 inch LaBr3 detector, two types of measurement instrumentation – an analogue one and a digital one, and a set of certified samples – a 207Bi point source and U and Pu CBNM standards. The results of our measurements indicate that the lowest contribution to the peak asymmetry and thus the smallest impact on the resolution of the 500 mm3 CdZnTe detector was achieved with the digital MCA. Analysis of acquired spectra allowed to reject poor quality measurement runs and produce summed spectra files with the least impact of instrumentation instabilities. This work is preliminary to further studies concerning the development of an isotopic composition determination algorithm particularly suited for CZT and LaBr3 detectors for safeguards applications.

In this study, calculation of decision threshold and detection limit expressed in counts for low-level radioactivity measurements were evaluated and compared to a Monte Carlo method for the case of paired Poisson-distributed observations, i.e. for discrete variables. The calculated characteristic limits obtained from Monte Carlo calculations were compared with analytical expressions given in literature. The results in this study show that the equations given by Currie are in good agreement with the results from the Monte Carlo calculations simulating nuclear counting applications with a low number of observed counts. An exception is observed for a background corresponding to zero counts. This study also shows that at a low number of counts, the specific boundary conditions of the interval that represents counts corresponding to the presence of the analyte (>or ≥), have an impact on the false positives and negatives rates as defined by the parameters α and β. [Display omitted] • Determination of critical limits in low-level measurements were evaluated. • Inconsistency exists in some definitions for decision threshold and detection limit. • 'Currie limits' are fit-for-purpose, if ISO 11929–2:2019 are considered in the calculation. [ABSTRACT FROM AUTHOR]

Calculation of the decision threshold and detection limit of a measurement, or measurement method, are crucial in order to decide if an analyte is present or not and with what confidence it can be quantified. That decision is important in view of possible actions if something would be detected. In this work, a method for calculating these limits using a Monte Carlo method is presented. In the Monte Carlo method any a priori distribution (e.g. normal distribution, rectangular distribution, triangular distribution) of an input quantity can be selected. Differences between the Monte Carlo calculated characteristic limits and the ones calculated according to ISO 11929:2010 is presented. Moreover, suggestions how to calculate the detection limit when it can not be calculated according to the ISO 11929:2010 are given. • Calculation of decision threshold and Minimum Detectable Activity, MDA, using a Monte Carlo method. • Monte Carlo calculation implemented in Excel. • Calculation using different modelling of the probability distribution of an efficiency transfer correction factor. • Possibility to obtain a MDA also when the uncertainty in the conversion factor is very large. [ABSTRACT FROM AUTHOR]

Plants have evolved sophisticated DNA repair mechanisms to cope with the deleterious effects of ultraviolet (UV)-induced DNA damage. Indeed, DNA repair pathways cooperate with epigenetic-related processes to efficiently maintain genome integrity. However, it remains to be deciphered how photodamages are recognized within different chromatin landscapes, especially in compacted genomic regions such as constitutive heterochromatin. Here we combined cytogenetics and epigenomics to identify that UV-C irradiation induces modulation of the main epigenetic mark found in constitutive heterochromatin, H3K9me2. We demonstrated that the histone demethylase, Jumonji27 (JMJ27), contributes to the UV-induced reduction of H3K9me2 content at chromocentres. In addition, we identified that JMJ27 forms a complex with the photodamage recognition factor, DNA Damage Binding protein 2 (DDB2), and that the fine-tuning of H3K9me2 contents orchestrates DDB2 dynamics on chromatin in response to UV-C exposure. Hence, this study uncovers the unexpected existence of an interplay between photodamage repair and H3K9me2 homeostasis., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)