Structural study of Pu1−xAmxO2 (x = 0.2; 0.5; 0.8) obtained by oxalate co-conversion

This study describes the synthesis and the characterisation of Pu_1−xAm_xO₂ (x = 0.2; 0.5; 0.8) mixed oxides obtained by oxalate co-conversion. We studied the self-irradiation effect in these compounds at the structural scale. We determined, for each composition, the initial lattice parameter and the equation describing its variation versus time and displacements per atom. Similarly to other α emitting compounds, it was observed a fast lattice parameter expansion rate, followed by a stabilisation at a maximum value. The observations also showed that the initial expansion rate varies according to the Am content and the maximum value to the Pu content. However, for all compositions, the lattice parameter relative variations are the same.     

Criticality qualification of a new Monte Carlo code for reactor core analysis

In order to accurately simulate Accelerator Driven Systems (ADS), the utilization of at least two computational tools is necessary (the thermal–hydraulic problem is not considered in the frame of this work), namely: (a) A High Energy Physics (HEP) code system dealing with the “Accelerator part” of the installation, i.e. the computation of the spectrum, intensity and spatial distribution of the neutrons source created by (p, n) reactions of a proton beam on a target and (b) a neutronics code system, handling the “Reactor part” of the installation, i.e. criticality calculations, neutron transport, fuel burn-up and fission products evolution. In the present work, a single computational tool, aiming to analyze an ADS in its integrity and also able to perform core analysis for a conventional fission reactor, is proposed. The code is based on the well qualified HEP code GEANT (version 3), transformed to perform criticality calculations. The performance of the code is tested against two qualified neutronics code systems, the diffusion/transport SCALE-CITATION code system and the Monte Carlo TRIPOLI code, in the case of a research reactor core analysis. A satisfactory agreement was exhibited by the three codes.     

Synergistic sterilization

Ten racing pigeons were infected experimentally with the paramyxovirus (PMV) type 1 of the pigeon. Within twelve weeks of observation, they were euthanized at different times. Their brains were examined for proteinase K resistant fibrils and histopathologically for spongiform lesions. No proteinase K resistant fibrils and no spongiform lesions could be detected in any case. Therefore, it is estimated that PMV type 1 of the pigeon is not likely to induce pathogenic mechanisms assumed for transmissible spongiform encephalopathies.     

Multicenter study on the clinical value of fetal pulse oximetry. II. Compared predictive values of pulse oximetry and fetal blood analysis. The French Study Group on Fetal Pulse Oximetry

OBJECTIVE: Our purpose was to compare the predictive value of intrapartum fetal pulse oximetry with that of fetal blood analysis for an abnormal neonatal outcome in case of an abnormal fetal heart rate. STUDY DESIGN: A prospective multicenter observational study was conducted from June 1994 to November 1995. Fetal oxygen saturation was continuously recorded with a Nellcor N-400 fetal pulse oximeter in case of an abnormal fetal heart rate during labor. Simultaneous readings of fetal oxygen saturation and fetal blood analysis obtained before birth (i.e., either at full dilatation or before cesarean section when indicated) were compared with the neonatal status. The criteria for an abnormal neonatal outcome were (1) an umbilical arterial blood pH < or = 7.15 and (2) a combined variable including 5-minute Apgar score < or = 7, umbilical arterial pH < or = 7.15, secondary respiratory distress, transfer in a neonatal care unit, or neonatal death. RESULTS: At a 7.20 threshold for fetal scalp pH and 30% for fetal oxygen saturation (i.e., the 10th percentile in the study population), the predictive value of fetal pulse oximetry was similar to that of fetal blood analysis for an arterial umbilical pH < or = 7.15 and for an abnormal neonatal outcome (positive predictive value 56% vs 55%, negative predictive value 81% vs 82%, sensitivity 29% vs 35%, and specificity 93% vs 91%, respectively). The receiver-operator characteristic curve showed similar performance of either technique for cutoff values < or = 7.20 for fetal blood pH and < or = 30% for fetal oxygen saturation, whereas fetal pulse oximetry became superior at higher thresholds. CONCLUSION: The predictive value of intrapartum fetal pulse oximetry can be favorably compared with that of fetal blood analysis. Randomized controlled management trials can now be performed to assess potential clinical benefits of this new tool.     

Towards a simple compressive strength test for earth bricks?

There is an increasing demand for earth construction in the world today but there is no consensus on the procedure to be used to measure the compressive strength of earth bricks. The study presented in this paper aims to propose a test procedure specific to earth bricks that would give the most realistic value of compressive strength while remaining as simple as possible. This study focused on four different bricks and consisted of measuring the compressive strength of these specimens by varying several parameters: specimen size, orientation, use of Teflon capping or not, and tests on dry sawn specimens, on half-bricks or on entire bricks. The results of the study show that the best compromise to achieve a simple and representative compressive strength test for earth bricks is to transform the bricks as little as possible before the test and thus to test entire bricks.     

Fava bean (Vicia faba L.) for food applications: From seed to ingredient processing and its effect on functional properties,antinutritional factors,flavor, and color

The food industry, along with the consumers, is interested in plant-based diet because of its health benefits and environmental sustainability. Vicia faba L. (V. faba) is a promising source of pulse proteins for the human diet and can yield potential nutritional and functional ingredients, namely, flours, concentrates, and isolates, which are relevant for industrial food applications. Different processes produce and functionalize V. faba ingredients relevant for industrial food applications, along with various alternatives within each unit operation used in their production. Processing modifies functional properties of the ingredients, which can occur by (i) changing in overall nutritional composition after processing steps and/or (ii) modifying the structure and conformation of protein and of other components present in the ingredients. Furthermore, V. faba limitations due to off-flavor, color, and antinutritional factors are influenced by ingredient production and processing that play a significant role in their consumer acceptability in foods. This review attempts to elucidate the influence of different ways of processing on the functional, sensory, and safety aspects of V. faba L. ingredients, highlighting the need for further research to better understand how the food industry could improve their utilization in the market.     

Digestibility of amino acids in soya-bean,sunflower and groundnut meal,measured in pigs with ileo-rectal anastomosis and isolation of the large intestine

Each of four littermate male pigs of 25 kg liveweight was surgically adapted to create a bypass of the large intestine by ileo-rectal anastomosis. The large intestine was sealed at both ends and a cannula was exteriorised from the lumen to allow any products of residual fermentation to escape. Ileal digesta were excreted via the anus. Three isonitrogenous diets were formulated containing soya-bean or groundnut (dehulled) or sunflower (not dehulled) meals as the sole protein sources. Each diet was fed, in turn, for 7 consecutive days to all pigs, and Heal digesta from feeds on days 5 and 6 (indicated by chromic oxide addition to feeds) were collected. This procedure was conducted twice for each diet. Apparent digestibility coefficients (AD) of nitrogen (N) and amino acids were calculated (as percentages of the respective intake). AD of N and the majority of amino acids of soya-bean and groundnut meals were greater (P<0.05) than those of sunflower meal. In the order soya-bean, groundnut and sunflower meal, coefficients were: for lysine, 87.7, 83.5, 71.0% (standard error of the differences between means (SED) 1.06); for threonine, 81.0, 80.5, 74.4% (SED 1.03); for methionine, 89.1, 84.9, 88.5% (SED 0.49); and for the sum of the amino acids, 85.4, 88.1, 78.8% (SED 0.75).     

Immune response to mouse mammary tumor virus in mice lacking the alpha/beta interferon or the gamma interferon receptor

Mouse mammary tumor virus (MMTV) is a retrovirus which induces a strong immune response and a dramatic increase in the number of infected cells through the expression of a superantigen (SAg). Many cytokines are likely to be involved in the interaction between MMTV and the immune system. In particular, alpha/beta interferon (IFN-alpha/beta) and gamma interferon (IFN-gamma) exert many antiviral and immunomodulatory activities and play a critical role in other viral infections. In this study, we have investigated the importance of interferons during MMTV infection by using mice with a disrupted IFN-alpha/beta or IFN-gamma receptor gene. We found that the SAg response to MMTV was not modified in IFN-alpha/betaR(0/0) and IFN-gammaR(0/0) mice. This was true both for the early expansion of B and T cells induced by the SAg and for the deletion of SAg-reactive cells at later stages of the infection. In addition, no increase in the amount of proviral DNA was detected in tissues of IFN-alpha/betaR(0/0) and IFN-gammaR(0/0) mice, suggesting that interferons are not essential antiviral defense mechanisms during MMTV infection. In contrast, IFN-gammaR(0/0) mice had increased amounts of IL-4 mRNA and an altered usage of immunoglobulin isotypes with a reduced frequency of IgG2a- and IgG3-producing cells. This was associated with lower titers of virus-specific antibodies in serum early after infection, although efficient titers were reached later.     

Contribution to the study of fatigue-crack propagation near threshold conditions

International Journal of Fracture -