The migratory abilities of motile human spermatozoa in vivo are essential for natural fertility, but it remains a mystery what properties distinguish the tens of cells which find an egg from the millions of cells ejaculated. To reach the site of fertilization, sperm must traverse narrow and convoluted channels, filled with viscous fluids. To elucidate individual and group behaviors that may occ...

Two small polypeptides, PorA and PorH, are known to form cell wall channels in Corynebacterium glutamicum and in Corynebacterium efficiens. The genes coding for both polypeptides are localized in close proximity to one another between the genes coding for GroEl2 and a polyphosphate kinase (PKK2). In this study, we investigated the relationship of PorA and PorH to one another. The results sugges...

The BK channel, a voltage- and Ca(2+)-gated large-conductance potassium channel with many important functions, is often localized at specific subcellular domains. Although proper subcellular localization is likely a prerequisite for the channel to perform its physiological functions, little is known about the molecular basis of localization. Here, we show that CTN-1, a homologue of mammalian α-...

Nonlinear advective adjustment of a discontinuity in free-surface height under gravity and rotation is considered, using the method of contour dynamics. After linear wave-adjustment has set up an interior jet and boundary currents in a wide (9 one Rossby radius) channel, fluid surges down-channel on both walls, rather than only that wall supporting a down-channel Kelvin wave. A wedgelike intrus...

Acoustofluidic devices for manipulating microparticles in fluids are appealing for biological sample processing due to their gentle and high-speed capability of sorting cell-scale objects. Such devices are generally limited to moving particles toward locations at integer fractions of the fluid channel width (1/2, 1/4, 1/6, etc.). In this work, we introduce a unique approach to acoustophoretic d...

Applying electrical fields is a simple and versatile method to manipulate and reconfigure optofluidic devices. Several methods to apply electric fields using electrodes on polymers or in the context of lab-on-a-chip devices exist. In this paper, we utilize an ion-implanted process to pattern electrodes within a fluidic channel made of polydimethylsiloxane (PDMS). Electrode structuring within th...

The present work investigates turbulent velocity and temperature fields subject to strong wall injection in a channel using a Direct Numerical Simulation technique. A simplified model problem of the internal flows inside the hybrid rocket motors where a regression process at the wall is idealized by the wall blowing has been considered to gain a better understanding of how the turbulent structu...

A new scaling is derived that yields a Reynolds number independent profile for all components of the stress in near-wall region wall bounded flows, including channel, pipe and boundary layer flows. The demonstrates important role played by shear fluctuations how large eddies determine dependence turbulence behavior.

The present paper is primarily concerned with modeling complex turbulent wall-bounded flow in spray-painting processes by using a commercial CFD code. Computational results of turbulent channel flow with low Reynolds numbers are compared with DNS data in order to obtain the performance of turbulence models and near wall treatments. The realizable k-ε model with the nonequilibrium wall function ...

The effects of wall inertia on instabilities in a collapsible channel with a long finite-length flexible wall containing a high Reynolds number flow of incompressible fluid are studied. Using the ideas of interactive boundary layer theory, the system is described by a one-dimensional model that couples inviscid flow outside the boundary layers formed on the channel walls with the deformation of...