Correlation effects during liquid infiltration into hydrophobic nanoporous mediums

Correlation effects arising during liquid infiltration into hydrophobic porous medium are considered. On the basis of these effects a mechanism of energy absorption at filling porous medium by nonwetting liquid is suggested. In accordance with this mechanism, the absorption of mechanical energy is a result expenditure of energy for the formation of menisci in the pores on the shell of the infinite cluster and expenditure of energy for the formation of liquid-porous medium interface in the pores belonging to the infinite cluster of filled pores. It was found that in dependences on the porosity and, consequently, in dependences on the number of filled pores neighbors, the thermal effect of filling can be either positive or negative and the cycle of infiltration-defiltration can be closed with full outflow of liquid. It can occur under certain relation between percolation properties of porous medium and the energy characteristics of the liquid-porous medium interface and the liquid-gas interface. It is shown that a consecutive account of these correlation effects and percolation properties of the pores space during infiltration allow to describe all experimental data under discussion

Effect of Fructooligosaccharide Metabolism on Chicken Colonization by an Extra-Intestinal Pathogenic Escherichia coli Strain

Extra-intestinal pathogenic Escherichia coli (ExPEC) strains cause many diseases in humans and animals. While remaining asymptomatic, they can colonize the intestine for subsequent extra-intestinal infection and dissemination in the environment. We have previously identified the fos locus, a gene cluster within a pathogenicity island of the avian ExPEC strain BEN2908, involved in the metabolism of short-chain fructooligosaccharides (scFOS). It is assumed that these sugars are metabolized by the probiotic bacteria of the microbiota present in the intestine, leading to a decrease in the pathogenic bacterial population. However, we have previously shown that scFOS metabolism helps BEN2908 to colonize the intestine, its reservoir. As the fos locus is located on a pathogenicity island, one aim of this study was to investigate a possible role of this locus in the virulence of the strain for chicken. We thus analysed fos gene expression in extracts of target organs of avian colibacillosis and performed a virulence assay in chickens. Moreover, in order to understand the involvement of the fos locus in intestinal colonization, we monitored the expression of fos genes and their implication in the growth ability of the strain in intestinal extracts of chicken. We also performed intestinal colonization assays in axenic and Specific Pathogen-Free (SPF) chickens. We demonstrated that the fos locus is not involved in the virulence of BEN2908 for chickens and is strongly involved in axenic chicken cecal colonization both in vitro and in vivo. However, even if the presence of a microbiota does not inhibit the growth advantage of BEN2908 in ceca in vitro, overall, growth of the strain is not favoured in the ceca of SPF chickens. These findings indicate that scFOS metabolism by an ExPEC strain can contribute to its fitness in ceca but this benefit is fully dependent on the bacteria present in the microbiota

Facial Cosmetics and Attractiveness: Comparing the Effect Sizes of Professionally-Applied Cosmetics and Identity

Forms of body decoration exist in all human cultures. However, in Western societies, women are more likely to engage in appearance modification, especially through the use of facial cosmetics. How effective are cosmetics at altering attractiveness? Previous research has hinted that the effect is not large, especially when compared to the variation in attractiveness observed between individuals due to differences in identity. In order to build a fuller understanding of how cosmetics and identity affect attractiveness, here we examine how professionally-applied cosmetics alter attractiveness and compare this effect with the variation in attractiveness observed between individuals. In Study 1, 33 YouTube models were rated for attractiveness before and after the application of professionally-applied cosmetics. Cosmetics explained a larger proportion of the variation in attractiveness compared with previous studies, but this effect remained smaller than variation caused by differences in attractiveness between individuals. Study 2 replicated the results of the first study with a sample of 45 supermodels, with the aim of examining the effect of cosmetics in a sample of faces with low variation in attractiveness between individuals. While the effect size of cosmetics was generally large, between-person variability due to identity remained larger. Both studies also found interactions between cosmetics and identity-more attractive models received smaller increases when cosmetics were worn. Overall, we show that professionally- applied cosmetics produce a larger effect than self-applied cosmetics, an important theoretical consideration for the field. However, the effect of individual differences in facial appearance is ultimately more important in perceptions of attractiveness

Sucrose is an early modulator of the key hormonal mechanisms controlling bud outgrowth in Rosa hybrida

Sugar has only recently been identified as a key player in triggering bud outgrowth, while hormonal control of bud outgrowth is already well established. To get a better understanding of sugar control, the present study investigated how sugar availability modulates the hormonal network during bud outgrowth in Rosa hybrida. Other plant models, for which mutants are available, were used when necessary. Buds were grown in vitro to manipulate available sugars. The temporal patterns of the hormonal regulatory network were assessed in parallel with bud outgrowth dynamics. Sucrose determined bud entrance into sustained growth in a concentration-dependent manner. Sustained growth was accompanied by sustained auxin production in buds, and sustained auxin export in a DR5::GUS-expressing pea line. Several events occurred ahead of sucrose-stimulated bud outgrowth. Sucrose upregulated early auxin synthesis genes (RhTAR1, RhYUC1) and the auxin efflux carrier gene RhPIN1, and promoted PIN1 abundance at the plasma membrane in a pPIN1::PIN1-GFP-expressing tomato line. Sucrose downregulated both RwMAX2, involved in the strigolactone-transduction pathway, and RhBRC1, a repressor of branching, at an early stage. The presence of sucrose also increased stem cytokinin content, but sucrose-promoted bud outgrowth was not related to that pathway. In these processes, several non-metabolizable sucrose analogues induced sustained bud outgrowth in R. hybrida, Pisum sativum, and Arabidopsis thaliana, suggesting that sucrose was involved in a signalling pathway. In conclusion, we identified potential hormonal candidates for bud outgrowth control by sugar. They are central to future investigations aimed at disentangling the processes that underlie regulation of bud outgrowth by sugar

CRF-Like Diuretic Hormone Negatively Affects Both Feeding and Reproduction in the Desert Locust, Schistocerca gregaria

Diuretic hormones (DH) related to the vertebrate Corticotropin Releasing Factor (CRF) have been identified in diverse insect species. In the migratory locust, Locusta migratoria, the CRF-like DH (CRF/DH) is localized in the same neurosecretory cells as the Ovary Maturating Parsin (OMP), a neurohormone that stimulates oocyte growth, vitellogenesis and hemolymph ecdysteroid levels in adult female locusts. In this study, we investigated whether CRF-like DH can influence feeding and reproduction in the desert locust, Schistocerca gregaria. We identified two highly similar S. gregaria CRF-like DH precursor cDNAs, each of which also encodes an OMP isoform. Alignment with other insect CRF-like DH precursors shows relatively high conservation of the CRF/DH sequence while the precursor region corresponding to OMP is not well conserved. Quantitative real-time RT-PCR revealed that the precursor transcripts mainly occur in the central nervous system and their highest expression level was observed in the brain. Injection of locust CRF/DH caused a significantly reduced food intake, while RNAi knockdown stimulated food intake. Therefore, our data indicate that CRF-like DH induces satiety. Furthermore, injection of CRF/DH in adult females retarded oocyte growth and caused lower ecdysteroid titers in hemolymph and ovaries, while RNAi knockdown resulted in opposite effects. The observed effects of CRF/DH may be part of a wider repertoire of neurohormonal activities, constituting an integrating control system that affects food intake and excretion, as well as anabolic processes like oocyte growth and ecdysteroidogenesis, following a meal. Our discussion about the functional relationship between CRF/DH and OMP led to the hypothesis that OMP may possibly act as a monitoring peptide that can elicit negative feedback effects

Transcriptional Control of Steroid Biosynthesis Genes in the Drosophila Prothoracic Gland by Ventral Veins Lacking and Knirps.

Specialized endocrine cells produce and release steroid hormones that govern development, metabolism and reproduction. In order to synthesize steroids, all the genes in the biosynthetic pathway must be coordinately turned on in steroidogenic cells. In Drosophila, the steroid producing endocrine cells are located in the prothoracic gland (PG) that releases the steroid hormone ecdysone. The transcriptional regulatory network that specifies the unique PG specific expression pattern of the ecdysone biosynthetic genes remains unknown. Here, we show that two transcription factors, the POU-domain Ventral veins lacking (Vvl) and the nuclear receptor Knirps (Kni), have essential roles in the PG during larval development. Vvl is highly expressed in the PG during embryogenesis and is enriched in the gland during larval development, suggesting that Vvl might function as a master transcriptional regulator in this tissue. Vvl and Kni bind to PG specific cis-regulatory elements that are required for expression of the ecdysone biosynthetic genes. Knock down of either vvl or kni in the PG results in a larval developmental arrest due to failure in ecdysone production. Furthermore, Vvl and Kni are also required for maintenance of TOR/S6K and prothoracicotropic hormone (PTTH) signaling in the PG, two major pathways that control ecdysone biosynthesis and PG cell growth. We also show that the transcriptional regulator, Molting defective (Mld), controls early biosynthetic pathway steps. Our data show that Vvl and Kni directly regulate ecdysone biosynthesis by transcriptional control of biosynthetic gene expression and indirectly by affecting PTTH and TOR/S6K signaling. This provides new insight into the regulatory network of transcription factors involved in the coordinated regulation of steroidogenic cell specific transcription, and identifies a new function of Vvl and Knirps in endocrine cells during post-embryonic development

Genetic variability for morphology, growth and forage yield among perennial diploid and tetraploid lucerne populations (Medicago sativa L)

The wide diversity within the Medicago sativa complex is well known, but comparative data on different populations representing the sub-species sativa and falcata are lacking. Morphological and agronomic characters of 25 populations or varieties of lucerne belonging to the M sativa complex were studied at Lusignan (France) in 1993 and 1994. The landraces and varieties of the sub-species sativa were clearly different from the wild populations of the 2 sub-species sativa and falcata by their erect growth habit, their fast regrowth after cutting, the absence of rhizomatous plants, their tall height and their high forage yield. Within the cultivated populations, those originating from northern France had a higher winter resistance than the Mediterranean populations, and higher yields. The winter resistance trait and the variegated flowers of the French sativa landraces show that they have integrated some traits belonging to sub-species falcata. The group of wild populations contained diploid and tetraploid populations, and sativa or falcata populations. Among the characters analysed, only flower colour made the distinction possible between the wild sativa populations from Spain (Mielga) with purple flowers and the falcata populations with yellow flowers. This convergence of forms between the 2 sub-species could be a strategy of tolerance to animal feeding and to treading.Variabilité génétique pour la morphologie, la croissance et le rendement en matière sèche chez la luzerne pérenne diploïde et tétraploïde (Medicago sativa L). La grande diversité du complexe Medicago sativa est bien connue, mais des données comparatives de différentes populations représentant les sous-espèces sativa et falcata manquent. Les caractéristiques morphologiques et agronomiques de 25 populations ou variétés de luzerne appartenant au complexe M sativa ont été étudiées à Lusignan (France) en 1993 et 1994. Les populations et variétés cultivées de la sous-espèce sativa se distinguent nettement des populations sauvages des 2 sous-espèces sativa et falcata par leur port dressé, leur repousse rapide après une coupe, leur hauteur élevée et leur fort rendement. Parmi les populations cultivées, celles originaires du nord de la France ont une résistance à l'hiver supérieure aux méditerranéennes, ainsi qu'un meilleur rendement. Par leurs caractères de résistance à l'hiver et leurs fleurs bigarrées, ces populations sativa françaises montrent qu'elles ont intégré certains caractères provenant de la ssp falcata. Le groupe des populations sauvages comprend à la fois des populations diploïdes et tétraploïdes, falcata ou sativa. Pour les caractères analysés, seule la couleur des fleurs permet de distinguer les populations sauvages sativa d'Espagne (Mielga) à fleurs violettes des populations falcata à fleurs jaunes. La convergence de forme de ces 2 sous-espèces pourrait représenter une stratégie de tolérance au pâturage

2002), Fluid in mineral interfaces—molecular simulations of structure and diffusion

[1] We study the effect of burial depth on thermodynamics and transport properties of fluids confined between mineral surfaces. The solvation curve and diffusion coefficients of fluid films confined between mineral surfaces have been obtained for different states of stress and temperature using Grand Canonical Monte Carlo and molecular dynamics simulations. Our results indicate that the mass transport coefficient (film thickness times diffusion coefficient) of the thin films of fluids trapped at grain contacts decrease by a factor 40 from 1 km to 3 km and 10 km. This effect has strong implications on the rates at which mechano-chemical processes of deformation (e.g. pressure solution) occur in the upper crust

CO2 evolution during the last millenium as recorded by Antarctic and Greenland ice

In order to study in detail the pre-industrial CO2 level (back to about 900 AD) and its temporal variations, several ice cores from Greenland and Antarctica were analysed in two laboratories, and compared with previous records. The agreement between the two laboratories and between the different cores of the same hemisphere is good. However, the comparison of the northern hemisphere (Greenland) and southern hemisphere (Antarctica) records shows values systematically higher in the north than in the south, ranging from 20 ppmv at the turn of this millennium to nearly zero around the 18th century. Based on our present knowledge of the carbon cycle, an inter-hemispheric gradient of 20 ppmv is unrealistic. Thus, in the oldest part of the record, at least one profile should not represent the true atmospheric CO2 concentrations. A companion paper by Anklin et al. (submitted), discusses the possible processes which can alter the atmospheric CO2 once trapped in the ice. Due to the fact that the impurity content is one order of magnitude lower in the Antarctic than in the Greenland ice, we are much more confident in the Antarctic record. The new results from D47 and D57 (Adélie Land) presented in this paper, confirm the CO2 fluctuation of about 10 ppmv at the end of the 13th century, previously observed by Siegenthaler et al. (1988) on an ice core drilled at South Pole. This fluctuation corresponds to a small imbalance of the carbon cycle (~ 0.3 GT C/ yr), but its duration led to a significant cumulative input into the atmosphere. The changes observed in the pre-industrial level are discussed in terms of climatic noise and variability