Dynamics and interactions of Quincke roller clusters: From orbits and flips to excited states.

Active matter systems may be characterized by the conversion of energy into active motion, e.g., the self-propulsion of microorganisms.

Probing excitations and cooperatively rearranging regions in deeply supercooled liquids.

Upon approaching the glass transition, the relaxation of supercooled liquids is controlled by activated processes, which become dominant at temperatures below the so-called dynamical crossover predicted by Mode Coupling theory (MCT). Two of the main frameworks rationalising this behaviour are dynamic facilitation theory (DF) and the thermodynamic scenario which give equally good descriptions of the available data. Only particle-resolved data from liquids supercooled below the MCT crossover can reveal the microscopic mechanism of relaxation.

Isomorphs in nanoconfined liquids.

We study in this paper the possible existence of Roskilde-simple liquids and their isomorphs in a rough-wall nanoconfinement. Isomorphs are curves in the thermodynamic phase diagram along which structure and dynamics are invariant in suitable nondimensionalized units. Two model liquids using molecular dynamics computer simulations are considered: the single-component Lennard-Jones (LJ) liquid and the Kob-Andersen binary LJ mixture, both of which in the bulk phases are known to have good isomorphs.

3D assessment of intervertebral disc degeneration in zebrafish identifies changes in bone density that prime disc disease.

Back pain is a common condition with a high social impact and represents a global health burden. Intervertebral disc disease (IVDD) is one of the major causes of back pain; no therapeutics are currently available to reverse this disease. The impact of bone mineral density (BMD) on IVDD has been controversial, with some studies suggesting osteoporosis as causative for IVDD and others suggesting it as protective for IVDD.

Transformed notochordal cells trigger chronic wounds in zebrafish, destabilizing the vertebral column and bone homeostasis.

Notochordal cells play a pivotal role in vertebral column patterning, contributing to the formation of the inner architecture of intervertebral discs (IVDs). Their disappearance during development has been associated with reduced repair capacity and IVD degeneration. Notochord cells can give rise to chordomas, a highly invasive bone cancer associated with late diagnosis.

A trusted node-free eight-user metropolitan quantum communication network.

Quantum communication is rapidly gaining popularity due to its high security and technological maturity. However, most implementations are limited to just two communicating parties (users). Quantum communication networks aim to connect a multitude of users.

Anisotropic viscoelastic phase separation in polydisperse hard rods leads to nonsticky gelation.

Spinodal demixing into two phases having very different viscosities leads to viscoelastic networks-i.e., gels-usually as a result of attractive particle interactions.

The Crystal Structure of Orthocetamol Solved by 3D Electron Diffraction.

Orthocetamol is a regioisomer of the well-known pain medication paracetamol and a promising analgesic and an anti-arthritic medicament itself. However, orthocetamol cannot be grown as single crystals suitable for X-ray diffraction, so its crystal structure has remained a mystery for more than a century. Here, we report the ab-initio structure determination of orthocetamol obtained by 3D electron diffraction, combining a low-dose acquisition method and a dedicated single-electron detector for recording the diffracted intensities.

Opposed flow focusing: evidence of a second order jetting transition.

We propose a novel microfluidic "opposed-flow" geometry in which the continuous fluid phase is fed into a junction in a direction opposite to the dispersed phase. This pulls out the dispersed phase into a micron-sized jet, which decays into micron-sized droplets. As the driving pressure is tuned to a critical value, the jet radius vanishes as a power law down to sizes below 1 μm.

Local structure in deeply supercooled liquids exhibits growing lengthscales and dynamical correlations.

Glasses are among the most widely used of everyday materials, yet the process by which a liquid's viscosity increases by 14 decades to become a glass remains unclear, as often contradictory theories provide equally good descriptions of the available data. Knowledge of emergent lengthscales and higher-order structure could help resolve this, but this requires time-resolved measurements of dense particle coordinates-previously only obtained over a limited time interval. Here we present an experimental study of a model colloidal system over a dynamic window significantly larger than previous measurements, revealing structural ordering more strongly linked to dynamics than previously found.

Structural-dynamical transition in the Wahnström mixture.

In trajectory space, dynamical heterogeneities in glass-forming liquids correspond to the emergence of a dynamical phase transition between an active phase poor in local structure and an inactive phase which is rich in local structure. We support this scenario with the study of a model additive mixture of Lennard-Jones particles, quantifying how the choice of the relevant structural and dynamical observable affects the transition in trajectory space. We find that the low mobility, structure-rich phase is dominated by icosahedral order.

Oil-in-water microfluidics on the colloidal scale: new routes to self-assembly and glassy packings.

We have developed norland optical adhesive (NOA) flow focusing devices, making use of the excellent solvent compatibility and surface properties of NOA to generate micron scale oil-in-water emulsions with polydispersities as low as 5%. While current work on microfluidic oil-in-water emulsification largely concerns the production of droplets with sizes on the order of 10s of micrometres, large enough that Brownian motion is negligible, our NOA devices can produce droplets with radii ranging from 2 μm to 12 μm. To demonstrate the utility of these emulsions as colloidal model systems we produce fluorescently labelled polydimethylsiloxane droplets suitable for particle resolved studies with confocal microscopy.

Polymer photonic microstructures for quantum applications and sensing.

We present modelling results for efficient coupling of nanodiamonds containing single colour centres to polymer structures on distributed Bragg reflectors. We explain how hemispherical and super-spherical structures redirect the emission of light into small numerical apertures. Coupling efficiencies of up to 68.

The role of fivefold symmetry in suppressing crystallization.

Although long assumed to have an important role in the suppression of crystallization and the development of glassformers, the effect of local fivefold symmetry has never been directly tested. Here we consider whether such suppression of crystallization has a kinetic or thermodynamic nature and investigate its mechanism. We introduce a model in which the degree of fivefold symmetry can be tuned by favouring arrangements of particles in pentagonal bipyramids.

Hydrophilic nanoparticles stabilising mesophase curvature at low concentration but disrupting mesophase order at higher concentrations.

Using high pressure small angle X-ray scattering (HP-SAXS), we have studied monoolein (MO) mesophases at 18 wt% hydration in the presence of 10 nm silica nanoparticles (NPs) at NP-lipid number ratios (ν) of 1 × 10(-6), 1 × 10(-5) and 1 × 10(-4) over the pressure range 1-2700 bar and temperature range 20-60 °C. In the absence of the silica NPs, the pressure-temperature (p-T) phase diagram of monoolein exhibited inverse bicontinuous cubic gyroid (Q), lamellar alpha (Lα), and lamellar crystalline (Lc) phases. The addition of the NPs significantly altered the p-T phase diagram, changing the pressure (p) and the temperature (T) at which the transitions between these mesophases occurred.

Chitin and carbon nanotube composites as biocompatible scaffolds for neuron growth.

The design of biocompatible implants for neuron repair/regeneration ideally requires high cell adhesion as well as good electrical conductivity. Here, we have shown that plasma-treated chitin carbon nanotube composite scaffolds show very good neuron adhesion as well as support of synaptic function of neurons. The addition of carbon nanotubes to a chitin biopolymer improved the electrical conductivity and the assisted oxygen plasma treatment introduced more oxygen species onto the chitin nanotube scaffold surface.

Precise, contactless measurements of the surface tension of picolitre aerosol droplets.

The surface composition and surface tension of aqueous droplets can influence key aerosol characteristics and processes including the critical supersaturation required for activation to form cloud droplets in the atmosphere. Despite its fundamental importance, surface tension measurements on droplets represent a considerable challenge owing to their small volumes. In this work, we utilize holographic optical tweezers to study the damped surface oscillations of a suspended droplet (<10 μm radius) following the controlled coalescence of a pair of droplets and report the first contactless measurements of the surface tension and viscosity of droplets containing only 1-4 pL of material.

Optics of cone photoreceptors in the chicken (Gallus gallus domesticus).

Vision is the primary sensory modality of birds, and its importance is evident in the sophistication of their visual systems. Coloured oil droplets in the cone photoreceptors represent an adaptation in the avian retina, acting as long-pass colour filters. However, we currently lack understanding of how the optical properties and morphology of component structures (e.

Multistate resistive switching in silver nanoparticle films.

Resistive switching devices have garnered significant consideration for their potential use in nanoelectronics and non-volatile memory applications. Here we investigate the nonlinear current-voltage behavior and resistive switching properties of composite nanoparticle films comprising a large collective of metal-insulator-metal junctions. Silver nanoparticles prepared via the polyol process and coated with an insulating polymer layer of tetraethylene glycol were deposited onto silicon oxide substrates.

Conductive-AFM Patterning of Organic Semiconductors.

Using a conductive atomic force microscope (c-AFM) redox-writing technique, it is shown that it is possible to locally, and reversibly, pattern conducting, and nonconducting features on the surface of a low molecular weight aniline-based organic (semi)-conductor thin film using a commercial c-AFM. It is shown that application of a voltage between the tip and sample causes localized redox reactions at the surface without damage.

Glycan variation and evolution in the eukaryotes.

In this review, we document the evolution of common glycan structures in the eukaryotes, and illustrate the considerable variety of oligosaccharides existing in these organisms. We focus on the families of N- and O-glycans, glycosphingolipids, glycosaminoglycans, glycosylphosphatidylinositol (GPI) anchors, sialic acids (Sias), and cytoplasmic and nuclear glycans. We also outline similar and divergent aspects of the glycans during evolution within the groups, which include inter- and intraspecies differences, molecular mimicry, viral glycosylation adaptations, glycosyltransferase specificity relating to function, and the natural dynamism powering these events.

Understanding nanoparticle cellular entry: A physicochemical perspective.

Understanding interactions between nanoparticles (NPs) with biological matter, particularly cells, is becoming increasingly important due to their growing application in medicine and materials, and consequent biological and environmental exposure. For NPs to be utilised to their full potential, it is important to correlate their functional characteristics with their physical properties, which may also be used to predict any adverse cellular responses. A key mechanism for NPs to impart toxicity is to gain cellular entry directly.

Mutual information reveals multiple structural relaxation mechanisms in a model glass former.

Among the key challenges to our understanding of solidification in the glass transition is that it is accompanied by little apparent change in structure. Recently, geometric motifs have been identified in glassy liquids, but a causal link between these motifs and solidification remains elusive. One 'smoking gun' for such a link would be identical scaling of structural and dynamic lengthscales on approaching the glass transition, but this is highly controversial.

FKBP12.6 activates RyR1: investigating the amino acid residues critical for channel modulation.

We have previously shown that FKBP12 associates with RyR2 in cardiac muscle and that it modulates RyR2 function differently to FKBP12.6. We now investigate how these proteins affect the single-channel behavior of RyR1 derived from rabbit skeletal muscle.

Photophoretic separation of single-walled carbon nanotubes: a novel approach to selective chiral sorting.

For over two decades single-walled carbon nanotubes (SWCNTs) have been used in a broad range of electronic and optical applications, however the selective chiral sorting of SWCNTs with guaranteed optoelectronics characteristics is imperative to the industrial realization of such applications. In this paper we provide the results of modeling an optical sorting method that utilizes the inherent opto-electronic properties of the SWCNTs, thus guaranteeing the properties of the extracted populations. Utilizing the resonant transfer of photonic momentum, we simulate chiral sorting of two chiral populations in an aqueous environment based on the frequency dependent optical absorption properties of the nanotubes.