Crossover between Athermal Jamming and the Thermal Glass Transition of Suspensions

The non-Newtonian flow behavior of thermal and athermal disordered systems of dispersed uniform particles at high densities have strikingly similar features. By investigating the flow curves of yield-stress fluids and colloidal glasses having different volume fractions, particle sizes, and interactions, we show that both thermal and athermal systems exhibit power-law scaling with respect to the glass and jamming point, respectively, with the same exponents. All yield-stress flow curves can be scaled onto a single universal curve using the Laplace pressure as the stress scale for athermal systems and the osmotic pressure for the thermal systems. Strikingly, the details of interparticle interactions do not matter for the rescaling, showing that they are akin to usual phase transitions of the same universality class. The rescaling allows us to predict the flow properties of these systems from the volume fraction and known material properties.

Stability of LAPONITE®-stabilized high internal phase Pickering emulsions under shear

We investigated LAPONITE®-stabilized emulsions. Confocal microscopy shows that the clay particles are not only located at the interface but also aggregate and form a gel in the continuous phase. Our results suggest that the formation of the emulsions is mostly due to this gel formation, rather than that the clay is an emulsifier.

Universal rescaling of flow curves for yield-stress fluids close to jamming

The experimental flow curves of four different yield-stress fluids with different interparticle interactions are studied near the jamming concentration. By appropriate scaling with the distance to jamming all rheology data can be collapsed onto master curves below and above jamming that meet in the shear-thinning regime and satisfy the Herschel-Bulkley and Cross equations, respectively. In spite of differing interactions in the different systems, master curves characterized by universal scaling exponents are found for the four systems. A two-state microscopic theory of heterogeneous dynamics is presented to rationalize the observed transition from Herschel-Bulkley to Cross behavior and to connect the rheological exponents to microscopic exponents for the divergence of the length and time scales of the heterogeneous dynamics. The experimental data and the microscopic theory are compared with much of the available literature data for yield-stress systems.

Some psychometric properties of the CAMCOG

The CAMCOG, the cognitive section of the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX), was administered twice to 53 patients with a clinical diagnosis ranging from no dementia to severe dementia. The stability of the total CAMCOG score was high (0.97). Patients with less than moderate dementia were differentiated well by the total score and by subscales with a range of more than 8 points, except when education was low or age was higher than 78. Because performance on most (sub)scales is modified by age and education level, stratified norms are desirable. Only the Praxis subscale, and specifically performance on drawing tasks, appeared to be influenced by depression.