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The liquid filament microrheometer originally described by Bazilevsky et al. (1990) provides a simple way of extracting material parameters for Newtonian and viscoelastic fluids from measurements of the capillary breakup of a thin fluid thread. However, there is an unresolved discrepancy in the value of the Newtonian viscosity obtained from the experimental(More)
The spinning of polymeric fibers, the processing of numerous foodstuffs and the peel & tack characteristics of adhesives is associated with the formation, stability and, ultimately, the longevity of thin fluid 'strands'. This tendency to form strands is usually described in terms of the tackiness of the fluid or by heuristic concepts such as 'stringiness'(More)
We investigate the steady and transient shear and extensional rheological properties of a series of model hydrophobically modified ethoxylate-urethane (HEUR) polymers with varying degrees of hydrophobicity. A new nonlinear two-species network model for these telechelic polymers is described which incorporates appropriate molecular mechanisms for the(More)
There is a need for new quantitative in vitro models of drug uptake and diffusion to help assess drug toxicity/efficacy as well as new more predictive models for drug discovery. We report a three-dimensional (3D) multilayer spheroid model and a new algorithm to quantitatively study uptake and inward diffusion of fluorescent calcein via gap junction(More)
Polymeric particles are used in a variety of applications such as systems for controlled chemical release, [1–9] optical materials , [10, 11] chromatographic media, [12] and various biological applications. [13–16] The physical and chemical properties of polymeric particles, such as their shape, size, porosity, surface charge, and hydrophilicity or(More)
The effective and robust separation of biomolecules of interest from patient samples is an essential step in diagnostic applications. We present a platform for the fast extraction of nucleic acids from clinical specimens utilizing paramagnetic PMPs, an oil-water interface, a small permanent magnet and a microfluidic channel to separate and purify captured(More)
As demonstrated by the recent 2012/2013 flu epidemic, the continual emergence of new viral strains highlights the need for accurate medical diagnostics in multiple community settings. If rapid, robust, and sensitive diagnostics for influenza subtyping were available, it would help identify epidemics, facilitate appropriate antiviral usage, decrease(More)
We elucidate mechanisms for colloidal gelation of attractive nanoemulsions depending on the volume fraction (ϕ) of the colloid. Combining detailed neutron scattering, cryo-transmission electron microscopy and rheological measurements, we demonstrate that gelation proceeds by either of two distinct pathways. For ϕ sufficiently lower than 0.23, gels exhibit(More)
1. Introduction For viscoelastic fluids such as polymer melts and solutions, the transient uniaxial extensional viscosity is a function of both the rate of stretching and the total deformation or strain imposed. Knowledge of the resulting material function is of great importance in governing the dynamics and stability of polymer processing operations such(More)
We present a novel microfluidic-based approach to detect ligation products. The conformal specificity of ligases is used in various molecular assays to detect point mutations. Traditional methods of detecting ligation products include denaturing gel electrophoresis, sequence amplification, and melting curve analysis. Gel electrophoresis is a labor- and(More)