Proceedings

EPJ E Highlight - Versatile method yields synthetic biology building blocks

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Fluorescence microscopy image of polymersomes, taken 3 days after production.

New high-throughput method to produce both liposomes and polymersomes on the same microfluidic chip

Synthetic biology involves creating artificial replica that mimic the building blocks of living systems. It aims at recreating biological phenomena in the laboratory following a bottom-up approach. Today scientists routinely create micro-compartments, so called vesicles, such as liposomes and polymersomes. Their membranes can host biochemical processes and are made of self-assembled lipids or a particular type of polymers, called block copolymers, respectively. In a new study, researchers have developed a high-throughput method--based on an approach known as microfluidics--for creating stable vesicles of controlled size. The method is novel in that it works for both liposomes and polymersomes, without having to change the design of the microfluidic device or the combination of liquids. Julien Petit from the Max Planck Institute for Dynamics and Self-Organisation (MPIDS) in Göttingen, Germany and colleagues recently published these findings in EPJ E.

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EPJ E Colloquium: nanoparticles, nanorods and nanosheets at fluid interfaces

pH-induced, SWCNT segregation transition

In this EPJ E Review, Toor, Feng and Russel present many examples of self-assembly of nanoscale materials (both synthetic and biological) such as nanoparticles, nanorods and nanosheets at liquid/liquid interfaces. For biological nanoparticles, the nanoparticle assembly at fluid interfaces provide a simple route for directing nanoparticles into 2-D or 3-D constructs with hierarchical ordering.

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EPJ E Highlight - Travelling wave drives magnetic particles

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Optical microscope images separated by 6.63 s showing the formation of chains between only the large particles starting from an initially random mixture of two particles sizes.

New method for selectively controlling the motion of multiple sized microspheres suspended in water

As our technology downsizes, scientists often operate in microscopic-scale jungles, where modern-day explorers develop new methods for transporting microscopic objects of different sizes across non uniform environments, without losing them. Now, Pietro Tierno and Arthur Straube from the University of Barcelona, Spain, have developed a new method for selectively controlling, via a change in magnetic field, the aggregation or disaggregation of magnetically interacting particles of two distinct sizes in suspension in a liquid. Previous studies only focused on one particle size. These results, just published in EPJ E, show that it is possible to build long chains of large particles suspended in a liquid, forming channels that drive the small particles to move along. This could be helpful, for example, when sorting magnetic beads by size, separating biological or chemical entities in lab-on-a-chip devices or transporting biological species to analyse them.

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EPJ E Highlight - Tumble-proof cargo transporter in biological cells

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The average number density field of particles in the vicinity of the motor

New model shows how collective transport by synthetic nanomotors along biopolymer filaments can be effectively directed

Ever wondered how a molecular nanomotor works when repairing DNA or transporting material such as organelles in the cell? Typically, nanomotors move along biopolymer filaments to go about their duties in the cell. To do so, they use the energy of chemical reactions derived from their surroundings to propel themselves. In a new study published in EPJ E, Mu-Jie Huang and Raymond Kapral from the University of Toronto in Ontario, Canada show that small synthetic motors can attach to polymeric filaments and - unlike what previous studies showed - move along without changing either their shape or the direction in which they set out to move. This makes it possible to effectively deliver the substances they transport, such as anti-cancer drugs or anti-pollutants.

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EPJ E News: Pawel Pieranski honored with the Prix Félix Robin 2015

We congratulate Professor Pawel Pieranski of the Laboratoire de Physique des Solides, Université Paris-Sud, who has been awarded the Prix Félix Robin* 2015 by the French Physical Society.

Today, 24 April, Pieranski will receive the prize from the president of the French CNRS Alain Fuchs during the award ceremony that will take place at the Palais de la Découverte in Paris. During the event Pieranski will give a presentation entitled “La beauté universelle des cristaux liquides” that will bring into focus the peculiarities of liquid crystals and how these materials challenge our understanding of the states of matter.

Pieranski is a long standing contributor to EPJ, especially EPJ E. His EPJ papers can be found here.

*The Prix Félix Robin 2015 is one of the 6 grand awards of the Société Française de Physique and the one with the longest tradition - it was instituted in 1922.

EPJ E Highlight - New insights into the evaporation patterns of coffee stains

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Deposits of silicon dioxide nanoparticles at pH2 and pH9 on glass substrates with driven menisci experiments

New factors influencing particle deposition via solvent evaporation and relevant to microchips manufacturing have now been elucidated

Few of us pay attention to the minutiae of coffee stains’ deposition patterns. However, physicists have previously explained the increased deposition of ground coffee particles near the edge of an evaporating droplet of liquid. They attributed it to the collective dynamics of ground coffee grains as the liquid evaporates along the contact line between the liquid coffee and the table. This kind of dynamics also governs microchip production, when particles are deposited on a substrate by means of solvent evaporation. However, until recently, explanations of how such evaporation patterns are formed did not account for the effect of the mutual interactions between electrically charged particles. Now, Diego Noguera-Marín from the University of Granada, Spain, and colleagues have found that particle deposition may be controlled by the interplay between the evaporation of the solvent via convection and the previously identified collective diffusion of suspension nanoparticles. These findings appear as part of an EPJ E topical issue, entitled Wetting and Drying: Physics and Pattern Formation.

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EPJ E Highlight - How to make porous materials dry faster

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A glass channel with a rectangular-like cross section closed at one end and open at the entrance for evporation. The receding air-water interface is qualitatively sketched

Physicists show that the shape of the air-water interface, when linked to capillarity, influences water retention or evaporation

Water in, water out: such is the cycle of porous material. In some cases, like with soils, it is preferable to keep water in. In others, it makes better economic and ecological sense to have porous materials dry faster, e.g. in the paper industries or with plasterboard manufacturing. Modeling how porous material retains water or dries up can be resolved by narrowing the focus down to a single porous channel; now, a team of physicists has uncovered subtle underlying effects. These include the local shape of the air and water interface, which, in turn, is influenced by the actual shape of the capillaries. Emmanuel Keita, a physicist from Paris-Est University, France, who is also affiliated with Harvard University, Massachusetts, USA, and colleagues have just published these results in EPJ E.

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EPJ E Highlight - When liquids get up close and personal with powders

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Schematic representation of the transfers of solvent to the polymer layer occurring during spreading, in the reference frame of the droplet

Scientists leave no stone unturned when studying how a liquid wets a powder

Every cook knows that dissolving powder into a liquid, such as semolina in milk or polenta in water, often creates lumps. What they most likely don’t know is that physicists spend a lot of time attempting to understand what happens in those lumps. In a review paper published in EPJ E, scientists from the École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI), France, share their insights following ten years of research into the wetting of soluble polymer substrates by droplets of solvents like water.

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EPJ E Highlight - Adjustable adhesion power: what fakirs can learn from geckos

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The model of adhesion between two patterned, yet elastic, surfaces

New study models adhesion force as key to contact between two rough, yet elastic, surfaces

Imagine a new type of tyres whose structure has been designed to have greater adhesion on the road. Quite a timely discussion during the long winter nights. French physicists have now developed a model to study the importance of adhesion in establishing contact between two patterned, yet elastic, surfaces. Nature is full of examples of amazing adjustable adhesion power, like the feet of geckos, covered in multiple hairs of decreasing size. Until now, most experimental and theoretical studies have only focused on the elastic deformation of surfaces, neglecting the adhesion forces between such surfaces. This new approach just published in EPJ E, by Laetitia Dies and colleagues from the Paris Sud University, France, matters when the scale of adhesive forces, is comparable to elastic forces on materials such a tyres.

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EPJE Colloquium: Dense granular flows - fluidity revisited

Local shear rate ˙Γ for a system of frictional soft grains
Bouzid et al.

In this new EPJ E Colloquium, a group of authors from ESPCI, Univ. Paris-Diderot and Univ. P.M. Curie use the interpretive frame-work of non-locality to describe the rheology and fluidity in dense granular flows. Is a “good fitting” of the velocity profiles sufficient to demonstrate the validity of a particular model for non-locality?

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The proceedings of the FUSION14 conference have been published online in EPJ Web of Conference in January 2015. The proceedings were sent to EDP Sciences in mid december 2014. It is remarkable that, despite the end of the year break and the relatively large number of contributions, the proceedings have appeared online so quickly.
The editorial team of the FUSION14 proceedings has very much appreciated the flexibility of EDP Sciences who could accommodate for our submission of the proceedings at a later date than expected as well as their professionalism.
This is not the first edition of FUSION proceedings to appear in EPJ Web of Conferences. It is also likely that the proceedings of future editions of this triennial conference will again be published in this journal.

Cédric Simenel, The Australian National University, Australia
Co-editor EPJ Web of Conferences vol. 86, 2015

ISSN: 2100-014X (Electronic Edition)

© EDP Sciences