Effective interactions in active Brownian suspensions

Active colloids exhibit persistent motion, which can lead to motility-induced phase separation (MIPS). However, there currently exists no microscopic theory to account for this phenomenon. We report a first-principles theory, free of fit parameters, for active spherical colloids, which shows explicitly how an effective many-body interaction potential is generated by activity and how this can rationalize MIPS. For a passively repulsive system the theory predicts phase separation and pair correlations in quantitative agreement with simulation. For an attractive system the theory shows that phase separation becomes suppressed by moderate activity, consistent with recent experiments and simulations, and suggests a mechanism for reentrant cluster formation at high activity

Green-Kubo approach to the average swim speed in active Brownian systems

We develop an exact Green-Kubo formula relating nonequilibrium averages in systems of interacting active Brownian particles to equilibrium time-correlation functions. The method is applied to calculate the density-dependent average swim speed, which is a key quantity entering coarse grained theories of active matter. The average swim speed is determined by integrating the equilibrium autocorrelation function of the interaction force acting on a tagged particle. Analytical results are validated using Brownian dynamics simulations

Order-disorder transition in swirled granular disks.

We study the order-disorder transition of horizontally swirled dry and wet granular disks by means of computer simulations. Our systematic investigation of the local order formation as a function of amplitude and period of the external driving force shows that a large cluster of hexagonally ordered particles forms for both dry and wet granular particles at intermediate driving energies. Disordered states are found at small and large driving energies. Wet granular particles reach a higher degree of local hexagonal order with respect to the dry case. For both cases we report a qualitative phase diagram showing the amount of local order at different state points. Furthermore, we find that the transition from hexagonal order to a disordered state is characterized by the appearance of particles with square local order

Peripheral monocytes of obese women display increased chemokine receptor expression and migration capacity.

Context: The activation of peripheral immune cells and the infiltration of immune cells into adipose tissue in obesity are implicated in the development of type 2 diabetes mellitus. Objective: Aim of the study was to compare peripheral immune cells from obese and normal-weight women with regard to composition of immune cell subpopulations, surface expression of the chemokine receptors CCR2, CCR3, CCR5 and CXCR3 and cell-intrinsic migration capacity. Design: Case-Control Study. Setting: University Clinical Study Centre. Patients: Obese females and normal-weight females were included for fluorescence activated cell sorting (FACS) analysis and migration assays. Main Outcome Measures: Peripheral blood mononuclear cells (PBMCs) were prepared from fasting blood samples and used for FACS analysis and migration assays. Results: An increase in the percentages of CD14(+)CD16(+) monocytes was observed in obese subjects compared to controls. The chemokine receptor (CCR) profile of monocytes differed significantly in the obese state, particularly CCR2 levels were increased. In addition, a higher chemotactic activity of monocytes from obese subjects was observed in a migration assay, which was associated with both insulin resistance and CCR2 expression. Conclusion: Our results suggest that the enhanced intrinsic migratory capacity of peripheral monocytes in obese women may be due to the increased chemokine receptor expression, further supporting a link between peripheral immune cell dysfunction and obesity

Efficient Vector Implementations of AES-Based Designs: A Case Study and New Implemenations for Grøstl,Efficient Vector Implementations of AES-Based Designs : a Case Study and New Implemenations [sic] for Grøstl

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