11 research outputs found
Non-Volatile Complementary Polarizer Spin-Transfer Torque On-Chip Caches: A Device/Circuit/Systems Perspective
10.1109/TMAG.2014.2326858IEEE TRANSACTIONS ON MAGNETICS501
Competing Fluid Forces Control Endothelial Sprouting in a 3-D Microfluidic Vessel Bifurcation Model
Sprouting angiogenesis—the infiltration and extension of endothelial cells from pre-existing blood vessels—helps orchestrate vascular growth and remodeling. It is now agreed that fluid forces, such as laminar shear stress due to unidirectional flow in straight vessel segments, are important regulators of angiogenesis. However, regulation of angiogenesis by the different flow dynamics that arise due to vessel branching, such as impinging flow stagnation at the base of a bifurcating vessel, are not well understood. Here we used a recently developed 3-D microfluidic model to investigate the role of the flow conditions that occur due to vessel bifurcations on endothelial sprouting. We observed that bifurcating fluid flow located at the vessel bifurcation point suppresses the formation of angiogenic sprouts. Similarly, laminar shear stress at a magnitude of ~3 dyn/cm2 applied in the branched vessels downstream of the bifurcation point, inhibited the formation of angiogenic sprouts. In contrast, co-application of ~1 µm/s average transvascular flow across the endothelial monolayer with laminar shear stress induced the formation of angiogenic sprouts. These results suggest that transvascular flow imparts a competing effect against bifurcating fluid flow and laminar shear stress in regulating endothelial sprouting. To our knowledge, these findings are the first report on the stabilizing role of bifurcating fluid flow on endothelial sprouting. These results also demonstrate the importance of local flow dynamics due to branched vessel geometry in determining the location of sprouting angiogenesis
Embedding Read-Only Memory in Spin-Transfer Torque MRAM-Based On-Chip Caches
10.1109/TVLSI.2015.2439733IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS243992-100
SPINTASTIC: Spin-based Stochastic Logic for Energy-efficient Computing
Conference on Design Automation Test in Europe (DATE)2015-April1575-157
Energy-Efficient MRAM Access Scheme Using Hybrid Circuits Based on Spin-Torque Sensors
10.1109/ICSENS.2013.668818212th IEEE Sensors Conference234-23
Spin-Transfer Torque Memories: Devices, Circuits, and Systems
10.1109/JPROC.2016.2521712PROCEEDINGS OF THE IEEE10471449-148
A Three-State Nanofluidic Field Effect Switch
We report a three-state nanofluidic
field effect switch in an asymmetrically gated device with a forward
(positive), off (zero), and a reverse (negative) current state for
tunable control of ionic transport by systematically controlling the
gate potential. The embedded gate electrode allows for modulation
of the ionic current through the 16 nm deep channels as a function
of electrolyte concentration and gate electrode location for a fixed
streamwise potential
Cation Dependent Surface Charge Regulation in Gated Nanofluidic Devices
Surface
charge governs nanoscale aqueous electrolyte transport,
both in engineered analytical systems and in biological entities such
as ion channels and ion pumps as a function of ion type and concentration.
Embedded electrodes in a nanofluidic channel, isolated from the fluid
in the channel by a dielectric layer, act as active, tunable gates
to systematically modify local surface charge density at the interface
between the nanochannel surface and the aqueous electrolyte solution,
causing significant changes in measured nanochannel conductance. A
systematic comparison of transport of monovalent electrolytes [potassium
chloride (KCl), sodium chloride (NaCl)], 2:1 electrolytes [magnesium
chloride (MgCl<sub>2</sub>), calcium chloride (CaCl<sub>2</sub>)],
and electrolyte mixtures (KCl + CaCl<sub>2</sub>) through a gated
nanofluidic device was performed. Ion–surface interactions
between divalent Ca<sup>2+</sup> and Mg<sup>2+</sup> ions and the
nanochannel walls reduced the native surface charge density by up
to ∼4–5 times compared to the monovalent cations. In
electrolyte mixtures, Ca<sup>2+</sup> was the dominating cation with
nanochannel conductance independent of KCl concentration. Systematic
changes in local electrostatic surface state induced by the gate electrode
are impacted by the divalent cation–surface interactions, limiting
modulation of the local surface potential by the gate electrode and
resulting in cation dependent nanoscale ion transport as seen through
conductance measurements and numerical models