We present an on-chip microfluidic sample concentrator and detection triggering system for microparticles based on a combination of insulator-based dielectrophoresis (iDEP) and electrical impedance measurement. This platform operates by first using iDEP to selectively concentrate microparticles of interest based on their electrical and physiological characteristics in a primary fluidic channel;...

Recent experiments suggest that shear-enhanced growth of concentration fluctuations in polymer solutions is strongly influenced by solid boundaries. We analyze the dynamics of a model of a sheared polymer solution, accounting for the effect of stress variations on mass flux and for wall-slip. If (and only if) these effects are present, the flow exhibits a boundary-localized instability consiste...

While the osmotic equation of state (e.o.s.) of off-lattice models of polymer solutions or melts can be readily computed from the contact theorem, according to which the osmotic pressure is proportional to the monomer density at a hard wall, the task is significantly more arduous for polymers on a lattice. For short chains or low polymer concentrations, the chemical potential may be calculated ...

Tissue engineering has shown great promise for creating biological alternatives for implants. In this approach, scaffolding plays a pivotal role. Hydroxyapatite mimics the natural bone mineral and has shown good bone-bonding properties. This paper describes the preparation and morphologies of three-dimensional porous composites from poly(L-lactic acid) (PLLA) or poly(D,L-lactic acid-co-glycolic...

Purpose: The objective of this study was to prepare Propranolol Hydrochloride controlled release matrix tablets and to investigate the effect of the polymer blends and the polymer concentration on drug release. Method: Propranolol Hydrochloride controlled release matrix tablets were prepared by direct compression technique. Hydroxypropylmethylcellulose K15M (HPMC K15M) and Carbopol 934P were us...

Polydimethyl siloxane (PDMS)–glass microchip has a very strong surface effect on polymerase chain reaction (PCR), leading to a very poor PCR yield. In the work reported here, practical dynamic passivation of surfaces of PDMS–glass microchip using polyethylene glycol (PEG) or polyvinylpyrrolidone (PVP) was achieved using a conventional thermocycler. The passivation procedure was cost-effective a...

We examined the extent to which the intracellular polymerization of sickle hemoglobin (HbS) can account for the severity of anemia and of vaso-occlusive manifestations in the various sickling syndromes. Polymer formation in sickle cell disease depends principally on the intraerythrocytic hemoglobin composition and concentration. In our studies, the polymer fraction in sickle red cells was deter...

Flexible polymers in dilute solution enhance the viscosity in slow flows. But in strong, rapidly varying, shear fields, they behave elastically. A turbulent cascade (from large to small scales) should thus be deeply modified when the elastic stresses become comparable to the Reynold's stress. A (tentative) scaling picture for these effects has been proposed by M. Tabor and the present author1):...

A new process technology modified from conventional coaxial electrospinning process has been developed to prepare polymer fibers from a high concentration solution. This process involves a pure solvent concentrically surrounding polymer fluid in the spinneret. The concentric spinneret was constructed simply by inserting a metal needle through a high elastic silica gel tube. Two syringe pumps we...