Effects of homogeneous-heterogeneous reactions in flow of nanofluid between two stretchable rotating disks

The present study analyzes nanofluid flow over a two infinite rotating disk. A magnetic field addressed on momentum equation. An effect of homogeneous-heterogeneous reaction on the fluid flow is investigated. The relevant system of governing equations is transformed into ordinary differential equations by using Von Karman transformations. Homotopy approaches for different physical parameters are examined graphically on appropriate profile. For greater (S1) the radial, axial and azimuthal velocities are hiked. Energy of liquid enhances with increasing thermophoresis parameter Nt. Local Skin friction coefficient diminishes with higher Reynolds number at lower disk and opposite behavior at upper disk. Moreover concentration field elevates while increasing heterogeneous parameter

MHD convection of nanofluid in porous medium influenced by slanted Lorentz force

This paper presents a numerical investigation on magneto-hydrodynamics combined convection in a nanofluid-saturated porous 2-D cavity with different tilting angles of applied magnetic field and aspect ratios. The moving upper horizontal wall is heated uniformly. The temperature along the bottom wall is a constant cold temperature while the adiabatic condition is maintained at the vertical sidewalls. The finite volume method is applied to solve the system of non-dimensional equations. The pertinent parameters of the current study are Hartmann number (Ha), solid volume fraction (χ), Richardson number (Ri), the aspect ratio (Ar), Darcy number (Da), and the inclination angle of the magnetic field (γ). The slope of applied magnetic field affects the magnetic field intensity and the overall rate of heat transfer is augmented in the forced convection regime than the mixed convection regime. The mean Nusselt number raises on increasing of Ar for all considered Richardson numbers. In the presence of magnetic field, the rate of heat transfer is almost equal to the amplification of solid volume concentration when Ar = 0.25, whereas, it increases for Ar > 0.25 with the raise in the solid volume concentration. An increase in Hartmann number and Darcy number is insignificant on mean rate of heat transfer in the mixed convection regime at Ar ≤ 0.5

Electroconductive nanoscale topography for enhanced neuronal differentiation and electrophysiological maturation of human neural stem cells

Biophysical cues, such as topography, and electrical cues can provide external stimulation for the promotion of stem cell neurogenesis. Here, we demonstrate an electroconductive surface nanotopography for enhancing neuronal differentiation and the functional maturation of human neural stem cells (hNSCs). The electroconductive nanopatterned substrates were prepared by depositing a thin layer of titanium (Ti) with nanograting topographies (150 to 300 nm groove/ridge, the thickness of the groove -150 mu m) onto polymer surfaces. The Ti-coated nanopatterned substrate (TNS) induced cellular alignment along the groove pattern via contact guidance and promoted focal adhesion and cytoskeletal reorganization, which ultimately led to enhanced neuronal differentiation and maturation of hNSCs as indicated by significantly elevated neurite extension and the upregulated expression of the neuronal markers Tuj1 and NeuN compared with the Ti-coated flat substrate (TFS) and the nanopatterned substrate (NS) without Ti coating. Mechanosensitive cellular events, such as beta 1-integrin binding/clustering and myosin-actin interaction, and the Rho-associated protein kinase (ROCK) and mitogen-activated protein kinase/extracellular signal regulated kinase (MEK-ERK) pathways, were found to be associated with enhanced focal adhesion and neuronal differentiation of hNSCs by the TNS. Among the neuronal subtypes, differentiation into dopa-minergic and glutamatergic neurons was promoted on the TNS. Importantly, the TNS increased the induction rate of neuron-like cells exhibiting electrophysiological properties from hNSCs. Finally, the application of pulsed electrical stimulation to the TNS further enhanced neuronal differentiation of hNSCs due probably to calcium channel activation, indicating a combined effect of topographical and electrical cues on stem cell neurogenesis, which postulates the novelty of our current study. The present work suggests that an electroconductive nanopatterned substrate can serve as an effective culture platform for deriving highly mature, functional neuronal lineage cells from stem cells © The Royal Society of Chemistry 20171121sciescopu

Three-dimensional brain-like microenvironments facilitate the direct reprogramming of fibroblasts into therapeutic neurons

Biophysical cues can improve the direct reprogramming of fibroblasts into neurons that can be used for therapeutic purposes. However, the effects of a three-dimensional (3D) environment on direct neuronal reprogramming remain unexplored. Here, we show that brain extracellular matrix (BEM) decellularized from human brain tissue facilitates the plasmid-transfection-based direct conversion of primary mouse embryonic fibroblasts into induced neuronal (iN) cells. We first show that two-dimensional (2D) surfaces modified with BEM significantly increase the generation efficiency of iN cells and enhance neuronal transdifferentiation and maturation. Moreover, in an animal model of ischaemic stroke, iN cells generated on the BEM substrates and transplanted into the brain led to significant improvements in locomotive behaviours. We also show that compared with the 2D BEM substrates, 3D BEM hydrogels recapitulating brain-like microenvironments further promote neuronal conversion and potentiate the functional recovery of the animals. Our findings suggest that 3D microenvironments can boost nonviral direct reprogramming for the generation of therapeutic neuronal cells. © 2018 The Author(s