Detection and Automated Scoring of Dicentric Chromosomes in Nonstimulated Lymphocyte Prematurely Condensed Chromosomes After Telomere and Centromere Staining

PurposeTo combine telomere and centromere (TC) staining of premature chromosome condensation (PCC) fusions to identify dicentrics, centric rings, and acentric chromosomes, making possible the realization of a dose–response curve and automation of the process.Methods and MaterialsBlood samples from healthy donors were exposed to 60Co irradiation at varying doses up to 8 Gy, followed by a repair period of 8 hours. Premature chromosome condensation fusions were carried out, and TC staining using peptide nucleic acid probes was performed. Chromosomal aberration (CA) scoring was carried out manually and automatically using PCC-TCScore software, developed in our laboratory.ResultsWe successfully optimized the hybridization conditions and image capture parameters, to increase the sensitivity and effectiveness of CA scoring. Dicentrics, centric rings, and acentric chromosomes were rapidly and accurately detected, leading to a linear-quadratic dose–response curve by manual scoring at up to 8 Gy. Using PCC-TCScore software for automatic scoring, we were able to detect 95% of dicentrics and centric rings.ConclusionThe introduction of TC staining to the PCC fusion technique has made possible the rapid scoring of unstable CAs, including dicentrics, with a level of accuracy and ease not previously possible. This new approach can be used for biological dosimetry in radiation emergency medicine, where the rapid and accurate detection of dicentrics is a high priority using automated scoring. Because there is no culture time, this new approach can also be used for the follow-up of patients treated by genotoxic therapy, creating the possibility to perform the estimation of induced chromosomal aberrations immediately after the blood draw

DP-Parse: Finding Word Boundaries from Raw Speech with an Instance Lexicon

International audienceFinding word boundaries in continuous speech is challenging as there is little or no equivalent of a 'space' delimiter between words. Popular Bayesian non-parametric models for text segmentation (Goldwater et al., 2006, 2009) use a Dirichlet process to jointly segment sentences and build a lexicon of word types. We introduce DP-Parse, which uses similar principles but only relies on an instance lexicon of word tokens, avoiding the clustering errors that arise with a lexicon of word types. On the Zero Resource Speech Benchmark 2017, our model sets a new speech segmentation state-of-theart in 5 languages. The algorithm monotonically improves with better input representations, achieving yet higher scores when fed with weakly supervised inputs. Despite lacking a type lexicon, DP-Parse can be pipelined to a language model and learn semantic and syntactic representations as assessed by a new spoken word embedding benchmark.

RENEB accident simulation exercise

Purpose: The RENEB accident exercise was carried out in order to train the RENEB participants in coordinating and managing potentially large data sets that would be generated in case of a major radiological event. Materials and methods: Each participant was offered the possibility to activate the network by sending an alerting email about a simulated radiation emergency. The same participant had to collect, compile and report capacity, triage categorization and exposure scenario results obtained from all other participants. The exercise was performed over 27 weeks and involved the network consisting of 28 institutes: 21 RENEB members, four candidates and three non-RENEB partners. Results: The duration of a single exercise never exceeded 10 days, while the response from the assisting laboratories never came later than within half a day. During each week of the exercise, around 4500 samples were reported by all service laboratories (SL) to be examined and 54 scenarios were coherently estimated by all laboratories (the standard deviation from the mean of all SL answers for a given scenario category and a set of data was not larger than 3 patient codes). Conclusions: Each participant received training in both the role of a reference laboratory (activating the network) and of a service laboratory (responding to an activation request). The procedures in the case of radiological event were successfully established and tested

Dose assessment intercomparisons within the RENEB network using G0-lymphocyte prematurely condensed chromosomes (PCC assay)

Purpose: Dose assessment intercomparisons within the RENEB network were performed for triage biodosimetry analyzing G0-lymphocyte PCC for harmonization, standardization and optimization of the PCC assay. Materials and methods: Comparative analysis among different partners for dose assessment included shipment of PCC-slides and captured images to construct dose-response curves for up to 6 Gy c-rays. Accident simulation exercises were performed to assess the suitability of the PCC assay by detecting speed of analysis and minimum number of cells required for categorization of potentially exposed individuals. Results: Calibration data based on Giemsa-stained fragments in excess of 46 PCC were obtained by different partners using galleries of PCC images for each dose-point. Mean values derived from all scores yielded a linear dose-response with approximately 4 excess-fragments/cell/Gy. To unify scoring criteria, exercises were carried out using coded PCC-slides and/or coded irradiated blood samples. Analysis of samples received 24 h post-exposure was successfully performed using Giemsa staining (1 excess-fragment/cell/Gy) or centromere/telomere FISH-staining for dicentrics. Conclusions: Dose assessments by RENEB partners using appropriate calibration curves were mostly in good agreement. The PCC assay is quick and reliable for whole- or partial-body triage biodosimetry by scoring excess-fragments or dicentrics in G0-lymphocytes. Particularly, analysis of Giemsa-stained excess PCC-fragments is simple, inexpensive and its automation could increase throughput and scoring objectivity of the PCC assay

RENEB intercomparison exercises analyzing micronuclei (Cytokinesis-block Micronucleus Assay)

Purpose: In the framework of the ‘Realizing the European Network of Biodosimetry’ (RENEB) project, two intercomparison exercises were conducted to assess the suitability of an optimized version of the cytokinesis-block micronucleus assay, and to evaluate the capacity of a large laboratory network performing biodosimetry for radiation emergency triages. Twelve European institutions participated in the first exercise, and four non-RENEB labs were added in the second one. Materials and methods: Irradiated blood samples were shipped to participating labs, whose task was to culture these samples and provide a blind dose estimate. Micronucleus analysis was performed by automated, semi-automated and manual procedures. Results: The dose estimates provided by network laboratories were in good agreement with true administered doses. The most accurate estimates were reported for low dose points (== 2.7 Gy) a larger variation in estimates was observed, though in the second exercise the number of acceptable estimates increased satisfactorily. Higher accuracy was achieved with the semi-automated method. Conclusion: The results of the two exercises performed by our network demonstrate that the micronucleus assay is a useful tool for large-scale radiation emergencies, and can be successfully implemented within a large network of laboratories

RENEB intercomparisons applying the conventional Dicentric Chromosome Assay (DCA)

Purpose: Two quality controlled inter-laboratory exercises were organized within the EU project ‘Realizing the European Network of Biodosimetry (RENEB)’ to further optimize the dicentric chromosome assay (DCA) and to identify needs for training and harmonization activities within the RENEB network. Materials and methods: The general study design included blood shipment, sample processing, analysis of chromosome aberrations and radiation dose assessment. After manual scoring of dicentric chromosomes in different cell numbers dose estimations and corresponding 95% confidence intervals were submitted by the participants. Results: The shipment of blood samples to the partners in the European Community (EU) were performed successfully. Outside the EU unacceptable delays occurred. The results of the dose estimation demonstrate a very successful classification of the blood samples in medically relevant groups. In comparison to the 1st exercise the 2nd intercomparison showed an improvement in the accuracy of dose estimations especially for the high dose point. Conclusions: In case of a large-scale radiological incident, the pooling of ressources by networks can enhance the rapid classification of individuals in medically relevant treatment groups based on the DCA. The performance of the RENEB network as a whole has clearly benefited from harmonization processes and specific training activities for the network partners

Integration of new biological and physical retrospective dosimetry methods into EU emergency response plans : joint RENEB and EURADOS inter-laboratory comparisons

Purpose: RENEB, 'Realising the European Network of Biodosimetry and Physical Retrospective Dosimetry,' is a network for research and emergency response mutual assistance in biodosimetry within the EU. Within this extremely active network, a number of new dosimetry methods have recently been proposed or developed. There is a requirement to test and/or validate these candidate techniques and inter-comparison exercises are a well-established method for such validation. Materials and methods: The authors present details of inter-comparisons of four such new methods: dicentric chromosome analysis including telomere and centromere staining; the gene expression assay carried out in whole blood; Raman spectroscopy on blood lymphocytes, and detection of radiation induced thermoluminescent signals in glass screens taken from mobile phones. Results: In general the results show good agreement between the laboratories and methods within the expected levels of uncertainty, and thus demonstrate that there is a lot of potential for each of the candidate techniques. Conclusions: Further work is required before the new methods can be included within the suite of reliable dosimetry methods for use by RENEB partners and others in routine and emergency response scenarios

Combination of a gasification process with a high temperature fuel cell (SOFC) for convert biomass into electricity

La pile SOFC, qui fonctionne entre 700 et 800°C, est appropriée pour valoriser du gaz issu de la gazéification de la biomasse en électricité. Son haut rendement électrique (50 à 60% ) permettrait de doubler celui des installations de cogénération par gazéification actuelles. Cette thèse, sous contrat Cifre entre la société S3D, l’Institut des Matériaux de Nantes et l’Ecole des Mines de Nantes, est associée au projet ValorPac, soutenu par l’ADEME et regroupant différents partenaires (IMN, Fiaxell, S3D et SAS Syngas). L’objectif est de prouver expérimentalement la faisabilité du couplage entre SOFC et gazéification de la biomasse. Les travaux ont abouti à la construction d’une unité pilo te de gazéification selon un concept breveté. Les tests ont validé le fonctionnement avec 7 kg.h - 1 de plaquettes de bois et 10 kg.h - 1 de granulés de bois. Une composition moyenne de 14% de CO, 15% d’H 2 , 20% de CO 2 , 1% de CH 4 et 49% de N 2 , a été obtenue. En parallèle le fonctionnement des cellules SOFC avec des gaz similaires à ceux de la gazéification de la biomasse a été validé. Les résultats ont montré que dans certaines conditions quelques ppmv d’H 2 S suffisent à dégrader de 20% les performances alors qu’ une teneur de 100 ppmv d’HCl n’affecte pas les réactions électrochimiques. Les travaux ont aussi validé l’utilisation de la Bauxaline® pour éliminer l’H 2 S à haute température. Il s’agit d’un coproduit industriel issu de l’extraction de l’alumine et contena nt 50% d’ oxydes de fer. Il a permis de réduire une teneur en H 2 S de 200 ppmv à moins de 8 ppmv pendant plusieurs heures. A 400°C et pour une percée de 1 ppmv la capacité de traitement a été estimée à 70 gS.kg - 1 .The SOFC, which operates between 700 and 800°C, is appropriate to convert the gas from biomass gasification into electricity. Its high electrical yield (50 - 60%) could double those of current CHP plants using gasification process. The objective of our work is to prove experimentally the feasibility of coupling SOFC and biomass gasification. This thesis is associated with ValorPac project in partnership with Institut des Matériaux of Nantes, S3D Company, Ecole des Mines of Nantes, Fiaxell and SAS Syngas compa nies and supported by ARNT and ADEME. During our work, a gasification pilot plant was built according to a patented concept. Its operation with 7 kg.h - 1 of wood chips and 10 kg.h - 1 of wood pellets was tested successfully. An average composition of 14% CO, 15% H 2 , 20% CO 2 , 1% CH 4 and 49% N 2 , was obtained. In parallel, operation of SOFC cells with gases similar to those of biomass gasification has been proved. Results showed that some ppmv of H 2 S lead to a 20% decrease of cell's power while 100 ppmv of HCl doesn’t affect the electrochemical reactions. Our work confirmed the use of Bauxaline® to eliminate H 2 S at high temperature. This material is an industrial byproduct derived from alu mina extraction which contains 50% of iron oxides. A content of 200 ppmv H 2 S can be reduced to 8 ppmv for several hours. Treatment capacity was estimated at 70 gS.kg - 1 with a breakthrough of 1 ppmv and an operating temperature of 400°

Adsorption Study on DDAB Bilayers Using Contrast Variation with SANS

Partition coefficients of solutes between bilayers and water are determined with a new method, using contrast variation with SANS. The isotopic composition of the solvent that annuls the contrast is shown to depend on thermodynamical quantities related to the adsorption. Experimental results are given for two organic solute molecules (lactitol and aniline) in the favorable case of the swollen lamellar phase obtained with DDAB double chain surfactant.