Emulsions stabilised by whey protein microgel particles: Towards food-grade Pickering emulsions

We have investigated a new class of food-grade particles, whey protein microgels, as stabilisers of triglyceride-water emulsions. The sub-micron particles stabilized oil-in-water emulsions at all pH with and without salt. All emulsions creamed but exhibited exceptional resistance to coalescence. Clear correlations exist between the properties of the microgels in aqueous dispersion and the resulting emulsion characteristics. For conditions in which the particles were uncharged, fluid emulsions with relatively large drops were stabilised, whereas emulsions stabilized by charged particles contained smaller flocculated drops. A combination of optical microscopy of the drops and spectrophotometry of the resolved aqueous phase allowed us to estimate the interfacial adsorption densities of the particles using the phenomenon of limited coalescence. We deduce two classes of particle arrangement. Complete adsorption of the particles was obtained when they were neutral or when their charges were screened by salt resulting in at least one particle monolayer at the interface. By contrast, only around 50% of the particles adsorbed when they were charged with emulsion drops being covered by less than half a monolayer. These findings were supported by direct visualization of drop interfaces using cryo-scanning electron microscopy. Uncharged particles were highly aggregated and formed a continuous 2-D network at the interface. Otherwise particles organized as individual aggregates separated by particle-free regions. In this case, we suggest that some particles spread at the interface leading to the formation of a continuous protein membrane. Charged particles displayed the ability to bridge opposing interfaces of neighbouring drops to form dense particle disks protecting drops against coalescence; this is the main reason for the flocculation and stability of emulsions containing sparsely covered drops. © 2014 the Partner Organisations

Datation des calcites et des grès de Fontainebleau : une remise à plat de l'âge des silicifications des terrains tertiaires du Bassin.de Paris

National audienceLa mise en lumière du rôle des périodes froides dans les mécanismes de précipitation de la silice permet de proposer un modèle de silicification unique, homogène et cohérent pour toutes les silicifications du Bassin de Paris : grès, calcaires silicifiés et meumières. Ce modèle doit être envisagé bien au-delà du Bassin de Paris, nombre de silicifications des formations tertiaires d’Europe, d’Amérique du nord et de régions altitudinales plus méridionales ( ?) méritent d’être revisitées avec un œil neuf

Optimization of sample preparation for MRI of formaldehyde-fixed brains

International audienceMagnetic resonance imaging of post-mortem brains allows long acquisition times up to several days and can be used to obtain high-resolution images at high field (7 T) which can be readily correlated with histological examination of the tissue. However, death and formaldehyde fixation are known to modify severely the relaxivity and diffusion properties of brain tissue. In particular, formaldehyde is known to shorten T2, which drastically reduces SNR.In order to counteract this effect and recover better SNR, free fixative can be washed out by soaking the sample in isotonic saline solution. This has been demonstrated in small biopsy-sized tissue samples, but little data is available concerning whole brain specimens.This study was designed to describe the kinetics of the change of relaxivity and diffusion properties of whole brain specimen at 7 T, during fixation, and during soaking in saline solution, in order to determine optimal soaking times.In the ewe brain, the fixation was found to stabilize after approximately 8 weeks, and the optimal duration of saline soaking is found to be around 3 weeks. These durations can be expected to be longer for larger specimen, such as human brains, which require longer penetration times

Hopf Algebras of Graphs

We define graded Hopf algebras with bases labeled by various types of graphs and hypergraphs, provided with natural embeddings into an algebra of polynomials in infinitely many variables. These algebras are graded by the number of edges and can be considered as generalizations of symmetric or quasi-symmetric functions

Cutting circuits with multiple two-qubit unitaries

Quasiprobabilistic cutting techniques allow us to partition large quantum circuits into smaller subcircuits by replacing non-local gates with probabilistic mixtures of local gates. The cost of this method is a sampling overhead that scales exponentially in the number of cuts. It is crucial to determine the minimal cost for gate cutting and to understand whether allowing for classical communication between subcircuits can improve the sampling overhead. In this work, we derive a closed formula for the optimal sampling overhead for cutting an arbitrary number of two-qubit unitaries and provide the corresponding decomposition. Interestingly, cutting several arbitrary two-qubit unitaries together is cheaper than cutting them individually and classical communication does not give any advantage. This is even the case when one cuts multiple non-local gates that are placed far apart in the circuit.Comment: 20 pages, 4 figures, added appendix A (circuit diagrams

Pour la singularité des connaissances issues de la recherche en entrepreneuriat et PME

Pour la singularité des connaissances issues de la recherche en entrepreneuriat et PMEMoteur du tissu économique local et international, l’entrepreneuriat en Afrique est à la croisée des dimensions économique, sociale, culturelle, religieuse, … A travers le contenu de ce numéro, la Revue Africaine de Management souhaite traduire et diffuser la complexité humaine de cette réalité. Partager la réalité entrepreneuriale africaine et donner la parole aux chercheurs qui la vivent, tel est l’objectif de ce numéro

Formin 2 links neuropsychiatric phenotypes at young age to an increased risk for dementia

Age-associated memory decline is due to variable combinations of genetic and environmental risk factors. How these risk factors interact to drive disease onset is currently unknown. Here we begin to elucidate the mechanisms by which post-traumatic stress disorder (PTSD) at a young age contributes to an increased risk to develop dementia at old age. We show that the actin nucleator Formin 2 (Fmn2) is deregulated in PTSD and in Alzheimer's disease (AD) patients. Young mice lacking the Fmn2 gene exhibit PTSD-like phenotypes and corresponding impairments of synaptic plasticity, while the consolidation of new memories is unaffected. However, Fmn2 mutant mice develop accelerated age-associated memory decline that is further increased in the presence of additional risk factors and is mechanistically linked to a loss of transcriptional homeostasis. In conclusion, our data present a new approach to explore the connection between AD risk factors across life span and provide mechanistic insight to the processes by which neuropsychiatric diseases at a young age affect the risk for developing dementia

Toward community standards in the quest for orthologs

The identification of orthologs—genes pairs descended from a common ancestor through speciation, rather than duplication—has emerged as an essential component of many bioinformatics applications, ranging from the annotation of new genomes to experimental target prioritization. Yet, the development and application of orthology inference methods is hampered by the lack of consensus on source proteomes, file formats and benchmarks. The second ‘Quest for Orthologs' meeting brought together stakeholders from various communities to address these challenges. We report on achievements and outcomes of this meeting, focusing on topics of particular relevance to the research community at large. The Quest for Orthologs consortium is an open community that welcomes contributions from all researchers interested in orthology research and applications. Contact: [email protected]