Orphan gene finding—an exon assembly approach

This paper introduces an algorithm for finding eukaryotic genes. It particularly addresses the problem of orphan genes, that is of genes that cannot, based on homology alone, be connected to any known gene family and to which it is therefore not possible to apply traditional gene finding methods. To the best of our knowledge, this is also the first algorithm that attempts to compare in an exact way two DNA sequences that contain both coding (i.e. exonic) and non-coding (i.e. intronic and, possibly, intergenic) parts. The comparison is performed following an algorithmical model of a gene that is as close as possible to the biological one (we consider in this paper the “one ORF, one gene” problem only). A gene is seen as a set of exons that are pieces of an assembly and are not independent. The algorithm is efficient enough: although the constants are higher than for usual sequence comparison, its time complexity is proportional to the product of the sequences lengths while its space complexity scales linearly with the length of the smallest sequence.     

Interactions between Polymeric Dispersants and Calcium Silicate Hydrates

To better understand the mechanism of interaction between hydrating silicate-based cements and polymeric dispersants of the type used as superplasticizers in modern construction concretes, two different types of polymeric dispersant were added (at concentrations of 1 and 10 g/L) during the synthesis of calcium silicate hydrate (C-S-H) via the pozzolanic reaction in dilute slurries of lime and reactive silica, at Ca/Si ratios in the range of 0.66–1.50. Although both polymers gave degrees of adsorption of >79% in all cases studied, no significant structural modifications of the resulting C-S-H products were observed via X-ray diffraction or ²⁹Si magic angle spinning–nuclear magnetic resonance. These results differ from recent work in which it was shown that similar types of polymer could intercalate into the interlayers of C-S-H that was made using an alternative process. It is suggested that the process by which the C-S-H is formed may have a strong influence on whether C-S-H can intercalate polymers. This observation is relevant to understanding the fate of such polymers in concrete.     

Effect of inoculation of Carnobacterium divergens V41, a bio-preservative strain against Listeria monocytogenes risk, on the microbiological, chemical and sensory quality of cold-smoked salmon

The aim of this study was to develop a bio-preservation strategy for cold-smoked salmon (CSS) by the use of lactic acid bacteria previously selected for their capability to inhibit the growth of Listeria monocytogenes in the product. The spoiling potential of three Carnobacterium strains (Carnobacterium divergens V41, Carnobacterium piscicola V1 and SF668) was tested in sterile CSS blocks inoculated by 10(4-5) CFU g(-)(1) and stored under vacuum for 9 days at 4 degrees C followed by 19 days at 8 degrees C. C. divergens V41 grew a little faster than the other strains and none of the three carnobacteria showed any adverse effect on quality of the product, i.e. no off-odour detected by a trained panel, no total volatile basic nitrogen (TVBN) production, no acidification and no biogenic amine except a slight production of tyramine. An application on commercial CSS was tested by spraying C. divergens V41 (10(4-5) CFU g(-1)) on slices of four batches freshly processed in different smoke-houses. Microbial, chemical and sensory characteristics were weekly compared to a control during 4 weeks of vacuum storage. When the natural microflora was initially weak (two batches<20 CFU g(-1)), C. divergens V41 quickly reached 10(7-8) CFU g(-1) and a slight inhibition of endogenous Enterobacteriaceae, lactobacilli and yeasts was observed. The presence of C. divergens V41 was slightly detected (odour and flavour) but none of the sample was considered as spoiled by the sensory panel. When the natural microflora was initially high (2 batches>10(4-5) CFU g(-1)), no effect on the microflora, TVBN and biogenic amine production, nor on the sensory characteristics was observed in presence of C. divergens V41. In conclusion, bio-preservation of CSS using lactic acid bacteria such as C. divergens V41 is a promising way to inhibit the growth of pathogenic bacteria such as L. monocytogenes with low effect on the quality of the product.     

Metaux lourds dans les sediments de l'estuaire de la loire

Estuaries, being interfaces between fluviatile and marine environments, are the scene of considerable physico-chemical and biological gradients which can have an effect on the distribution of metallic elements between the solid and dissolved phases. The purpose of the present study was to determine the relative influence of each parameter in this distribution.The study included two series of samples (ICOLO 26 and ICOLO 32) taken by means of the Schipeck grab at 19 selected points of the estuary as indicated in Fig. 1.Within the framework of this study we first investigated and were able to determine the origin and evolution of the metallic elements in the Loire estuary.Pollution levelTable 1 and Fig. 2 summarize the results: firstly, the metallic element contents are relatively low, indicating that pollution is not very strong. Secondly, the contents measured in the different samples vary considerably due to the great heterogeneity of sample composition and particle-size distribution.Upstream-downstream evolutionFigure 2 shows that the longitudinal profiles for metals are very similar to those obtained for the different characteristics of the sediments. Such an observation has already been made by various authors. Owing to the existence of these relationships, we believe, as do Boust et al. (1981), that it is preferable to interpret the results relative to metals obtained on a given site in terms of the various characteristics of the sediment. In Fig. 3, the metallic element contents (ICOLO 26 samples) is thus plotted against organic carbon. As shown in the figure, there is a very good relationship between the two parameters. Figures 2 and 3 indicate that the contents are uniform throughout the estuary with no evidence of further significant sedimentation this uniformity being due to tidal action. Owing to this uniformity, the impact of significant discharges is highly localized except for the wastewater from the city of Nantes as a whole, whose impact which is felt along the entire estuary.The relationship between copper and volatile matter for the ICOLO 32 samples, as represented in Fig. 4, shows that the points fall into two groups, which are the same whatever the explanatory parameter involved. Though the results are more uniform for the ICOLO 26 than for the ICOLO 32 samples, Fig. 6 clearly shows that the “marine” points stand out in both series of samples. This is indicative of a reduction in contents in the downstream direction, especially noticeable beyond point B (Zn, Cr, Ni) or even M (Cd, Cu, Pb).The seasonal evolution is clearly shown on the “metal-characteristic of sediment” graphs by the comparison of the slopes of the lines linking the same point sampled during the two sampling campaigns. The example of copper is shown in Fig. 7.On the whole, analysis of the results derived from the study of one characteristics of the sediment, indicates that only limited enrichment or depletion occurs at a point over a period of time. This probably reflects a good constancy over time of the metallic flux in the estuary. There is little doubt that changes in the composition of the sediment, will cause changes in the trapping of the metallic flux. In this case, variations in contents do not reflect alterations in the metallic flux over the sediment, but the varying capacity of the sediment under investigation to trap the same polluting flux according to is own composition.This study was also productive in the investigation of the various phenomena responsible for the reduction in metal contents during estuarial transit, which phenomenon can be expected to occur in a large number of estuaries.The impact depends on the chemical properties of the element under investigation.Solubilization of metallic elements due to to increased salinity occurs but plays only a secondary role in the upstream-downstream reductions. This is presumably because of the low percentages of metal absorbed in relation to the total amount of metals associated with the sediments.The reduction in metal contents related to the degradation of organic matter also occurs but it is of little significance compared with the overall phenomenon. The disappearance of metals associated with organic matter could well be related to salinity.The considerable reduction of contents in the lower estuary markedly occurs downstream of the salinity front and precisely where the first sediments characteristic of the marine environment are encountered. Consequently, the most obvious parameter responsible for the reduction in the metallic element contents is the mixing of relatively laden fluviatile sediment with “clean” marine sediments.     

Les dèterminants de la procrastination académique: Un modèle médiationnel du contexte familial et des processus du soi.

Connell and Wellborn proposed a model which posits that the social context influences the development of self system processes which in turn have an impact on school engagement. The purpose of the present study was to test the validity of the Connell and Wellborn's model in line with academic procrastination. The model suggests that self-determination in family activities (implication) and the quality of the relation between parents and their children (structure) are positively associated to children's self-system processes (competence, autonomy, and relatedness). Moreover, the model proposes that children's self-system processes are negatively related to academic procrastination. Participants were 100 families (father, other, and children) from the Quebec city area. Results from path analysis supported the model. Theoretical implications of the findings are discussed in line with Connell and Wellborn's model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of various models for the simulation of a Core Disruptive Accident in the MARA 10 mock-up

During a Hypothetical Core Disruptive Accident in a Liquid Metal Fast Breeder Reactor, it is assumed that the core of the nuclear reactor melts down partially and that the interaction between hot molten fuel and relatively cold liquid sodium creates a high-pressure gas bubble in the core. The violent expansion of this bubble loads and deforms the reactor vessel and the internal structures, thus endangering the safety of the nuclear plant.The MARA 10 experimental test simulates a Core Disruptive Accident in a 1/30-scale mock-up schematising a reactor block. In the mock-up, the liquid sodium cooling the reactor core is replaced by water and the argon blanket laying below the reactor roof is simulated by an air blanket. The explosion is triggered by an explosive charge.This paper presents some models available within the EUROPLEXUS code to simulate a Core Disruptive Accident and an analysis of the computed results. In particular, results are compared with experimental measurements and previous numerical simulations carried out with the codes SIRIUS and CASTEM-PLEXUS.     

Etude de la resistivité de corps pulvérulents à base de carbone en fonction de la compression

Electrical resistance measurements were performed on different varieties of carbon blacks (Sterling Fr, MT, S, Black Pearls 2) under compression up to 660 kgf/cm² to determine the real resistivity of the carbon material. The general shape of the curves log p= - s log P are in good agreement with those reported by Mrozowski. Two theories have been proposed to explain the mechanism of the current flow through the particles. Holm's Contacts and the Tunnel effect between particles. The results for thermal blacks seem to agree with the first interpretation while the behaviour of the Channel blacks rather follows the second.     

Effects of pressure on poly(ether-ether-ketone) (PEEK) sintering mechanisms

This study deals with the understanding of the sintering mechanisms that occur during consolidation of an ultra-high-performance polymer: poly(ether-ether-ketone). In particular, we investigated the effects of uniaxial pressure during spark plasma sintering (SPS) processing. Glass-transition temperature (T_g) measurements under loading, stress–strain curves and scanning electron microscopy analysis allowed us to determine the role of pressure intensity and temperature of application on macromolecular chain mobility in both the bulk and the surface of the particles. First, a loss of chain mobility in the bulk of the particles was observed under high pressure. Second, it was shown that high pressure applied at low temperature leads to friction effects between the particles which enhances chain mobility in the particle shell through a local melting phenomenon. These experimental conditions favor the healing of particles and high cohesion was then observed in the resulting sintered samples. The level of friction is enhanced when pressure is applied at a low temperature since the powders are still in a glassy state. Finally, the achievement of cohesive grain boundaries was found to be related to the location and conformation of chain ends. Good healing between particles can only occur if a sufficient number of chain ends are available at the surface of the particle shell. We showed that the native powder state plays a significant role. The direct use of as-received powder leads to final material exhibiting good cohesion whereas pretreatments of the native powder are highly detrimental. It should be noted that this processing does not affect the high initial degree of crystallinity because no bulk melting is observed during consolidation by sintering. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47645.     

From contact angle titration to chemical force microscopy: a new route to assess the pH-dependent character of the stratum corneum

Despite of its complex multicomponent organization and its compact architecture, the Stratum corneum (SC) is not completely impermeable to substances directly applied on the skin surface. A huge number of works have been dedicated to the understanding of the mechanisms involved in substance permeation by exploring deeper layers than the SC itself. Surprisingly, there is a poor interest in studies relating to interactions which may occur in the near-surface region (i.e. approximately 1 nm depth) of the SC. In this work, equilibrium proton-transfer reactions have been used as probes to define in a fundamental point of view the nature of the SC interactions with its environment. Such titration curves are investigated on 'in vitro' SC (isolated SC from abdominal skin tissue) and on 'in vivo' volar forearm (a sebum poor area). The results are discussed in term of work of adhesion and surface pKa values. Because SC can 'reconstruct' under heating, influence of the temperature on titration curves is investigated and the role of the different components is discussed. Different sigmoidal transitions were observed. Two common pKa values (pKa(1) = 4 and pKa(2) = 11.5) were clearly identified in both cases and associated to an acid-base character. By playing with the temperature of 'in vitro' SC, the 'accessibility' of polar functions was increased, thus refining the results by revealing an amphoteric character with an acid-to-base transition at pH 3.5 and two acid transitions at pH = 6.5 and pH = 11.5. Adhesion forces between an Atomic Force Microscopy (AFM) tip and a single isolated corneocyte through buffered liquid media were also investigated to better understand the role of the individual corneocytes.