Mechanical testing of colloidal solids with millipascal stress and single-particle strain resolution.

We introduce a technique, traction rheoscopy, to carry out mechanical testing of colloidal solids. A confocal microscope is used to directly measure stress and strain during externally applied deformation. The stress is measured, with single-mPa resolution, by determining the strain in a compliant polymer gel in mechanical contact with the colloidal solid.

Ultrasoft silicone gels with tunable refractive index for traction force microscopy.

We formulate and characterize silicone gels near the gelation threshold with tunable refractive index, 1.4 < < 1.49, and small viscoelastic moduli, '∼1 Pa, for use in traction force microscopy.

Local-heterogeneous responses and transient dynamics of cage breaking and formation in colloidal fluids.

Quantifying the interactions in dense colloidal fluids requires a properly designed order parameter. We present a modified bond-orientational order parameter, ψ̄6, to avoid problems of the original definition of bond-orientational order parameter. The original bond-orientational order parameter can change discontinuously in time but our modified order parameter is free from the discontinuity and, thus, it is a suitable measure to quantify the dynamics of the bond-orientational ordering of the local surroundings.

Structural responses of quasi-two-dimensional colloidal fluids to excitations elicited by nonequilibrium perturbations.

We investigate the response of a dense monodisperse quasi-two-dimensional colloid suspension when a particle is dragged by a constant velocity optical trap. Consistent with microrheological studies of other geometries, the perturbation induces a leading density wave and trailing wake. We also use a hybrid version of Stokesian dynamics simulations to parse direct colloid-colloid and hydrodynamic interactions.

A computer-assisted microscopic analysis of bone tissue developed inside a polyactive polymer implanted into an equine articular surface.

One of the most promising applications for the restoration of small or moderately sized focal articular lesions is mosaicplasty (MP). Although recurrent hemarthrosis is a rare complication after MP, recently, various strategies have been designed to find an effective filling material to prevent postoperative bleeding from the donor site. The porous biodegradable polymer Polyactive (PA; a polyethylene glycol terephthalate - polybutylene terephthalate copolymer) represents a promising solution in this respect.

Automated detection of neonate EEG sleep stages.

The paper integrates and adapts a range of advanced computational, mathematical and statistical tools for the purpose of analysis of neonate sleep stages based on extensive electroencephalogram (EEG) recordings. The level of brain dysmaturity of a neonate is difficult to assess by direct physical or cognitive examination, but dysmaturity is known to be directly related to the structure of neonatal sleep as reflected in the nonstationary time series produced by EEG signals which, importantly, can be collected trough a noninvasive procedure. In the past, the assessment of sleep EEG structure has often been done manually by experienced clinicians.