1,032 research outputs found
Synergistic actions between angiotensin-converting enzyme inhibitors and statins in atherosclerosis
Aims: Hypertension and hypercholesterolemia are independent risk factors for atherosclerotic cardiovascular disease (ASCVD) by acting directly on the endothelium and activating the renin-angiotensin aldosterone system (RAAS) and mevalonate pathways. This review examines how the severity and duration of these risk factors may influence the cardiovascular risk through a reciprocal interplay leading to oxidative stress and pro-inflammatory response.
Data synthesis: The review highlights the clinical evidence supporting the benefits of statins and angiotensin-converting enzyme (ACE) inhibitors for hypertension, lipid disorders and ASCVD management, both individually and combined, at all stages of the cardiovascular continuum.
Conclusion: Drug strategies incorporating an ACE-inhibitor and a statin, and in particular perindopril and atorvastatin, have consistently demonstrated reductions in the rate of ASCVD events in patients with hypertension and lipid disorders, cementing their position as first-line therapies for the management of atherosclerosis complications
Anomalous Transport in Sketched Nanostructures at the LaAlO3/SrTiO3 Interface
The oxide heterostructure LaAlO3/SrTiO3 supports a two-dimensional electron
liquid with a variety of competing phases including magnetism,
superconductivity and weak antilocalization due to Rashba spin-orbit coupling.
Further confinement of this 2D electron liquid to the quasi-one-dimensional
regime can provide insight into the underlying physics of this system and
reveal new behavior. Here we describe magnetotransport experiments on narrow
LaAlO3/SrTiO3 structures created by a conductive atomic force microscope
lithography technique. Four-terminal local transport measurements on
~10-nm-wide Hall bar structures yield longitudinal resistances that are
comparable to the resistance quantum h/e2 and independent of the channel
length. Large nonlocal resistances (as large as 10^4 ohms) are observed in some
but not all structures with separations between current and voltage that are
large compared to the 2D mean-free path. The nonlocal transport is strongly
suppressed by the onset of superconductivity below ~200 mK. The origin of these
anomalous transport signatures is not understood, but may arise from coherent
transport defined by strong spin-orbit coupling and/or magnetic interactions
"Water-cycle" mechanism for writing and erasing nanostructures at the LaAlO3/SrTiO3 interface
Nanoscale control of the metal-insulator transition in LaAlO3/ SrTiO3
heterostructures can be achieved using local voltages applied by a conductive
atomic-force microscope probe. One proposed mechanism for the writing and
erasing process involves an adsorbed H2O layer at the top LaAlO3 surface. In
this picture, water molecules dissociates into OH- and H+ which are then
selectively removed by a biased AFM probe. To test this mechanism, writing and
erasing experiments are performed in a vacuum AFM using various gas mixtures.
Writing ability is suppressed in those environments where H2O is not present.
The stability of written nanostructures is found to be strongly associated with
the ambient environment. The self-erasure process in air can be strongly
suppressed by creating a modest vacuum or replacing the humid air with dry
inert gas. These experiments provide strong constraints for theories of both
the writing process as well as the origin of interfacial conductance.Comment: 11 pages, 3 figure
Spiking Neural Networks for Inference and Learning: A Memristor-based Design Perspective
On metrics of density and power efficiency, neuromorphic technologies have
the potential to surpass mainstream computing technologies in tasks where
real-time functionality, adaptability, and autonomy are essential. While
algorithmic advances in neuromorphic computing are proceeding successfully, the
potential of memristors to improve neuromorphic computing have not yet born
fruit, primarily because they are often used as a drop-in replacement to
conventional memory. However, interdisciplinary approaches anchored in machine
learning theory suggest that multifactor plasticity rules matching neural and
synaptic dynamics to the device capabilities can take better advantage of
memristor dynamics and its stochasticity. Furthermore, such plasticity rules
generally show much higher performance than that of classical Spike Time
Dependent Plasticity (STDP) rules. This chapter reviews the recent development
in learning with spiking neural network models and their possible
implementation with memristor-based hardware
Graphene-Complex-oxide Nanoscale Device Concepts
The integration of graphene with complex-oxide heterostructures such as
LaAlO/SrTiO offers the opportunity to combine the multifunctional
properties of an oxide interface with the electronic properties of graphene.
The ability to control interface conduction through graphene and understanding
how it affects the intrinsic properties of an oxide interface are critical to
the technological development of novel multifunctional devices. Here we
demonstrate several device archetypes in which electron transport at an oxide
interface is modulated using a patterned graphene top gate. Nanoscale devices
are fabricated at the oxide interface by conductive atomic force microscope
(c-AFM) lithography, and transport measurements are performed as a function of
the graphene gate voltage. Experiments are performed with devices written
adjacent to or directly underneath the graphene gate. Unique capabilities of
this approach include the ability to create highly flexible device
configurations, the ability to modulate carrier density at the oxide interface,
and the ability to control electron transport up to the
single-electron-tunneling regime, while maintaining intrinsic transport
properties of the oxide interface. Our results facilitate the design of a
variety of nanoscale devices that combine unique transport properties of these
two intimately coupled two-dimensional electron systems.Comment: 27 pages, 10 figure
Analysis of the intraspinal calcium dynamics and its implications on the plasticity of spiking neurons
The influx of calcium ions into the dendritic spines through the
N-metyl-D-aspartate (NMDA) channels is believed to be the primary trigger for
various forms of synaptic plasticity. In this paper, the authors calculate
analytically the mean values of the calcium transients elicited by a spiking
neuron undergoing a simple model of ionic currents and back-propagating action
potentials. The relative variability of these transients, due to the stochastic
nature of synaptic transmission, is further considered using a simple Markov
model of NMDA receptos. One finds that both the mean value and the variability
depend on the timing between pre- and postsynaptic action-potentials. These
results could have implications on the expected form of synaptic-plasticity
curve and can form a basis for a unified theory of spike time-dependent, and
rate based plasticity.Comment: 14 pages, 10 figures. A few changes in section IV and addition of a
new figur
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