Mass transfer in developing flow of a reactive mixture through a curved cylindrical tube.

Mass transfer to the reactive wall of a curved cylindrical tube is analyzed in the combined entry region where both momentum and concentration boundary layers are developing. The velocity and concentration distributions developing from uniform inlet profiles are obtained using perturbation analysis, accounting for acceleration of the inviscid flow outside the boundary layer arising from channel curvature and flow displacement. The enhancement in the average flux of the reactive species at the tube wall downstream of the inlet is determined and compared to predictions of numerical simulations.

Engineering Microgel Packing to Tailor the Physical and Biological Properties of Gelatin Methacryloyl Granular Hydrogel Scaffolds.

Granular hydrogel scaffolds (GHS) are fabricated via placing hydrogel microparticles (HMP) in close contact (packing), followed by physical and/or chemical interparticle bond formation. Gelatin methacryloyl (GelMA) GHS have recently emerged as a promising platform for biomedical applications; however, little is known about how the packing of building blocks, physically crosslinked soft GelMA HMP, affects the physical (pore microarchitecture and mechanical/rheological properties) and biological (in vitro and in vivo) attributes of GHS. Here, the GHS pore microarchitecture is engineered via the external (centrifugal) force-induced packing and deformation of GelMA HMP to regulate GHS mechanical and rheological properties, as well as biological responses in vitro and in vivo.

Quadri-Chamber Thrombi and Impending Paradoxical Embolism: Thrombus in Transit Through Patent Foramen Ovale.

Thrombus-in-transit through patent foramen ovale (PFO) is an extremely rare diagnosis that can often be associated with pulmonary embolism. Currently, data exists to guide management options; however, there is no medical consensus with regard to the optimal treatment strategy for thrombus-in-transit through PFO.

Enzyme Catalysis Causes Fluid Flow, Motility, and Directional Transport on Supported Lipid Bilayers.

The dynamic interplay between the composition of lipid membranes and the behavior of membrane-bound enzymes is critical to the understanding of cellular function and viability, and the design of membrane-based biosensing platforms. While there is a significant body of knowledge about how lipid composition and dynamics affect membrane-bound enzymes, little is known about how enzyme catalysis influences the motility and lateral transport on lipid membranes. Using enzyme-attached lipids in supported bilayers (SLBs), we provide direct evidence of catalysis-induced fluid flow that underlies the observed motility on SLBs.

Critical conditions for development of a second pair of Dean vortices in curved microfluidic channels.

The centrifugal force in flow through a curved channel initiates a hydrodynamic instability that results in the development of Dean vortices, a pair of counter-rotating roll cells across the channel that deflect the high velocity fluid in the center toward the outer (concave) wall. When this secondary flow toward the concave (outer) wall is too strong to be dissipated by viscous effects, an additional pair of vortices emerges near the outer wall. Combining numerical simulation and dimensional analysis, we find that the critical condition for the onset of the second vortex pair depends on γ^{1/2}Dn (γ: channel aspect ratio; Dn: Dean number).