RADIOLYTIC CORROSION OF GRAIN BOUNDARIES ONTO THE UO2 TRISO PARTICLE SURFACE

International audienceThis work is dealing with the understandingof the corrosion mechanisms at solid/solutioninterface and taking into account for the4He2+ions irradiation effects on these mechanisms.These corrosion and4He2+ions radiolysis phenomena append at solid/solution interface andwill be studied at a μmetric scale by the Raman spectroscopy. Moreover, a4He2+ionsirradiation appends onto a low volume and let usto control the irradiated area (solution, solidor interface). For the solid, the chemical species induced by4He2+ions radiolysis of water aresuch reactive and are involved in classical corrosion mechanisms of UO2. Moreover, we wantto study the impact of the4He2+ions radiolysis of water layers physisorbed into the surfaceonto corrosion mechanisms. That is the reason why we want to use a local irradiation, allowedby the4He2+ions ion beam provided by the ARRONAX cyclotron (E = 64.7 MeV). In thiswork an experimental apparatus will be performed in order to characterize solid/solutioninterface at μmetric scale by Raman spectroscopy under4He2+ions irradiation provided by thecyclotron ARRONAX facility. The leaching experiments under irradiation will be performedfor a short time in order to study the parametersduring the fast instantrelease step. The grainboundaries effect will be studied by the comparison between one TRISO particles set (solidswith grain boundaries) and oneTRISO particles set previously washed by one acid solution(solid without grain boundaries). The role of H2will be studied by the comparison betweenexperiments under Ar or Ar/H2atmosphere. The dose rate range will be between 0 and 100Gy/min by using the alpha ion beam which letus control the dose set down into the sample.For all these experiments, measurements will be performed by thein situRaman spectroscopyduring the irradiation in orderto follow the formation/consumption of the secondary phasesformed onto the solid. The SEM will be performed in order to characterize the grainboundaries and the secondary phases formed bythe leaching/irradiation experiments. TheμGC is used to measure the PH2into the irradiation cell tofollow the production/consumptionof this gaseous species formed by the water radiolysis and consumed by the leaching process

IMPACT OF WATER RADIOLYSIS ON URANIUM DIOXIDE CORROSION

International audienc

Disabilities and Activities of Daily Living Among Veterans With Old Hip Disarticulation and Transpelvic Amputation

Background: The Iran-Iraq imposed war lasted eight years and was one of the longest wars of the last century. Twenty-three years have passed since the war ended, but little has been discussed about the long-term results of war amputations in the literature. Objectives: In this long-term study, we have evaluated the activities of daily living among veterans with hip or hemipelvis amputations. Patients and Methods: A cross-sectional study was performed on Iran-Iraq war veterans with hip or hemipelvis amputations in Iran. Eighty-four (96.5%) veterans out of 87 registered veterans with hip or hemipelvis amputations participated in the study. The degree of independence for activities of daily living (ADL) was assessed by the Barthel index. The degree of independence for instrumental activities of daily living (IADL) was assessed by the Lawton-Brody scale. Results: The average follow-up time was 26.6 ± 3.7 years. The average age of veterans was 44.1±7 years old. Of 84 amputees, 57 (67.85%) had limitations in at least one domain of the ADL. The most common single item that affected the patients was ascending and descending stairs seen in 45 (78.9%) veterans, followed by eating seen in 4 (7.01%) veterans. In addition, 70 (83.33%) had limitations in at least one domain of the IADL. The most common single item that affected the veterans was shopping seen in 56 (80%), followed by responsibility for own medications seen in 13 (18.57%) veterans. Spearman correlation coefficient of the sum scores of ADL and IADL showed an intermediate to strong correlation (r = 0.58). Conclusions: Increasing dependency in ADL is accompanied by increasing dependency in IADL. In the past, the duty of health care providers was saving the life of veterans due to injuries while at present, because these injuries occurred in young and healthy individuals, the need for increased function is being highlighted

Developing a Questionnaire for Iranian Women's Attitude on Medical Ethics in Vaginal Childbirth

Background: Vaginal delivery is one of the challenging issues in medical ethics. It is important to use an appropriate instrument to assess medical ethics attitudes in normal delivery, but the lack of tool for this purpose is clear. Objectives: The aim of this study was to develop and validate a questionnaire for the assessment of women’s attitude on medical ethics application in normal vaginal delivery. Patients and Methods: This methodological study was carried out in Iran in 2013 - 2014. Medical ethics attitude in vaginal delivery questionnaire (MEAVDQ) was developed using the findings of a qualitative data obtained from a grounded theory research conducted on 20 women who had vaginal childbirth, in the first phase. Then, the validation criteria of this tool were tested by content and face validity in the second phase. Exploratory factor analysis was used for construct validity and reliability was also tested by Cronbach’s alpha coefficient in the third phase of this study. SPSS version 13 was used in this study. The sample size for construct validity was 250 females who had normal vaginal childbirth. Results: In the first phase of this study (tool development), by the use of four obtained categories and nine subcategories from grounded theory and literature review, three parts (98-items) of this tool were obtained (A, B and J). Part A explained the first principle of medical ethics, part B pointed to the second and third principles of medical ethics, and part J explained the fourth principle of medical ethics. After evaluating and confirming its face and content validity, 75 items remained in the questionnaire. In construct validity, by the employment of exploratory factor analysis, in parts A, B and J, 3, 7 and 3 factors were formed, respectively; and 62.8%, 64% and 51% of the total variances were explained by the obtained factors in parts A, B and J, respectively. The names of these factors in the three parts were achieved by consideration of the loading factor and medical ethics principles. The subscales of MEAVDQ showed significant reliability. In parts A, B and J, Cronbach’s alpha coefficients were 0.76, 0.72 and 0.68, respectively and for the total questionnaire, it was 0.72. The results of the test–retest were satisfactory for all the items (ICC = 0.60 - 0.95). Conclusions: The present study showed that the 59-item MEAVDQ was a valid and reliable questionnaire for the assessment of women’s attitudes toward medical ethics application in vaginal childbirth. This tool might assist specialists in making a judgment and plan appropriate for women in vaginal delivery management

Identification de génotypes-S chez les descendances d’amandiers par les méthodes NEPHGE et PCR

Almond (P. amygdalus Batsch) shows a gametophytic self-incompatibility system controlled by a multiallelic locus, known as the locus S. Self-compatibility has been related to Sf allele presence and this trait has become a priority in the main almond breeding programs and the search for new cultivars is focused on the evaluation of desirable traits in autogamous seedlings. Traditionally, self-compatibility has been assessed in almond by laborious and time consuming methods, such as determination of fruit set in bagged branches or microscopic observation of pollen tube growth after self-pollination in laboratory conditions. Recently, molecular methods have been developed to assess the S-genotype, such as the identification of stylar S-RNases by NEPHGE (non equilibrium pH gradient electro focusing) and the use of conserved and specific PCR primers for the amplification of fragments from the different S alleles. In this research we applied these molecular methods for the S-genotype assessment in two almond breeding progenies, from the crosses of the self-compatible elite selection 'G-2-25' (S11Sf) of the CITA, as female parent, with two self-incompatible cultivars, 'Desmayo Largueta' (S1S25) and 'Marcona' (S11S12), as male parents. Although no discrepancies were found between the two methods, PCR was more suitable than NEPHGE for S-genotype assessment. PCR is easier to optimize, cheaper, more precise and reliable. It is also possible to assess the genotype sooner than with NEPHGE, as flowers are not required for the determination, allowing an earlier elimination of the seedlings. In the 'G-2-25' (S11Sf) x 'Marcona' (S11S12) progeny, the ratio of genotypes was 42% S11S12 and 58% SfS12, approaching the Mendelian laws of transmission in spite of the slightly higher proportion of self-compatible seedlings. In the other family, 'G-2-25' (S11Sf) x 'Desmayo Largueta' (S1S25), four S-genotypes are possible, but the ratios obtained were 21% S1S11, 53% S1Sf, 0% S11S25, and 26% SfS25. These results showed that pollen carrying the S25 allele had only a 26% fertilization success as compared to 73 of pollen carrying the S1 allele. The absence of S11S25 seedlings may imply the expression of a homozygous lethal trait in these zygotes and the distortion of the Mendelian ratiosL’amandier (P. amygdalus Batsch) montre un système d’auto-incompatibilité gamétophytique contrôlé par un locus multiallélique, connu comme locus S. L’auto-compatibilité a été reliée à la présence de l’allèle Sf et cette caractéristique est devenue une priorité pour les principaux programmes d’amélioration de l’amandier, et ainsi la recherche de nouveaux cultivars se focalise sur l’évaluation des caractères désirables pour les plants autogames. Traditionnellement, l’auto-compatibilité a été évaluée chez les amandiers par des méthodes laborieuses et prenant beaucoup de temps, telles que la détermination de la nouaison pour les branches ensachées ou l’observation microscopique de la croissance des tubes de pollen après auto-pollinisation en conditions de laboratoire. Récemment, des méthodes moléculaires ont été développées pour évaluer le génotype-S, telles que l’identification de S-RNases stylaires par NEPHGE (non equilibrium pH gradient electro-focusing) et l’utilisation d’amorces PCR conservées et spécifiques pour l’amplification de fragments provenant de différents allèles-S. Pour cette recherche nous avons appliqué ces méthodes moléculaires pour l’évaluation du génotype-S chez les descendances améliorées de deux amandiers, à partir des croisements d’une sélection d’élite auto-compatible 'G-2-25' (S11Sf) du CITA, comme parent femelle, avec deux cultivars auto-incompatibles, 'Desmayo Largueta' (S1S25) et 'Marcona' (S11S12), comme parents mâles. Bien que l’on n’ait pas trouvé de divergences entre les deux méthodes, la PCR était plus adéquate que NEPHGE pour l’évaluation du génotype-S. La PCR est plus facile à optimiser, moins onéreuse, plus précise et fiable. Il est également possible d’évaluer le génotype plus tôt qu’avec NEPHGE, étant donné qu’il n’est pas nécessaire d’obtenir des fleurs pour la détermination, permettant ainsi une élimination précoce des plants. Dans la descendance de 'G-2-25' (S11Sf) 'Marcona' (S11S12), le quotient des génotypes était de 42% S11S12 et de 58% SfS12, se rapprochant des lois mendéliennes de transmission malgré la proportion légèrement plus élevée de plants auto-compatibles. Pour l’autre famille, 'G-2-25' (S11Sf) 'Desmayo Largueta' (S1S25), quatre génotypes-S sont possibles, mais les quotients obtenus étaient de 21% S1S11, 53% S1Sf, 0% S11S25, et 26% SfS25. Ces résultats montrent que le pollen portant l’allèle S25 avait une réussite de fertilisation d’uniquement 26% comparée à 73 pour le pollen portant l'allèle S1. L’absence de plants S11S25 pourrait faire penser à l’expression d’un caractère létal homozygote chez ces zygotes et à la distortion des quotients mendélien

Radiolytic Corrosion of Uranium Dioxide: Role of Molecular Species

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The properties of ”dark” ΛCDM halos in the Local Group

We examine the baryon content of low-mass Λ cold dark matter (ΛCDM) haloes (108 < M200/M⊙ < 5 × 109) using the APOSTLE cosmological hydrodynamical simulations. Most of these systems are free of stars and have a gaseous content set by the combined effects of cosmic reionization, which imposes a mass-dependent upper limit, and of ram-pressure stripping, which reduces it further in high-density regions. Haloes mainly affected by reionization (RELHICS; REionization-Limited H I Clouds) inhabit preferentially low-density regions and make up a population where the gas is in hydrostatic equilibrium with the dark matter potential and in thermal equilibrium with the ionizing UV background. Their thermodynamic properties are well specified, and their gas density and temperature profiles may be predicted in detail. Gas in RELHICS is nearly fully ionized but with neutral cores that span a large range of H I masses and column densities and have negligible non-thermal broadening. We present predictions for their characteristic sizes and central column densities; the massive tail of the distribution should be within reach of future blind H I surveys. Local Group RELHICS (LGRs) have some properties consistent with observed Ultra Compact High Velocity Clouds (UCHVCs) but the sheer number of the latter suggests that most UCHVCs are not RELHICS. Our results suggest that LGRs (i) should typically be beyond 500 kpc from the Milky Way or M31; (ii) have positive Galactocentric radial velocities; (iii) H I sizes not exceeding 1 kpc, and (iv) should be nearly round. The detection and characterization of RELHICS would offer a unique probe of the small-scale clustering of CDM

The chosen few: the low mass halos that host faint galaxies

Since reionization prevents star formation in most halos below 3 x 10^9 solar masses, dwarf galaxies only populate a fraction of existing dark matter halos. We use hydrodynamic cosmological simulations of the Local Group to study the discriminating factors for galaxy formation in the early Universe and connect them to the present-day properties of galaxies and halos. A combination of selection effects related to reionization, and the subsequent evolution of halos in different environments, introduces strong biases between the population of halos that host dwarf galaxies, and the total halo population. Halos that host galaxies formed earlier and are more concentrated. In addition, halos more affected by tidal stripping are more likely to host a galaxy for a given mass or maximum circular velocity, vmax, today. Consequently, satellite halos are populated more frequently than field halos, and satellite halos of 10^8 - 10^9 solar masses or vmax of 12 - 20 km/s, similar to the Local Group dwarf spheroidals, have experienced a greater than average reduction in both mass and vmax after infall. They are on closer, more radial orbits with higher infall velocities and earlier infall times. Together, these effects make dwarf galaxies highly biased tracers of the underlying dark matter distribution