Vortex core polarity switching in NiFe disks has been evidenced using an all-electrical magnetoresistive rectification scheme. Simulation and experiments yield a consistent rectified signal loss when ...driving core gyration at high powers. With increasing power, the frequency range over which the loss occurs grows and the resonance downshifts in frequency, consistent with nonlinear core dynamics and periodic core polarity switching induced by the core reaching its critical velocity. Core-polarity-dependent rectification signals enable an independent verification of the switched core polarity. We also demonstrate the ability to impede core polarity switching by displacing the core towards the disk's edge where an increased core stiffness reduces the core velocity.
Devices enabling early detection of low concentrations of leaking hydrogen and precision measurements in a wide range of hydrogen concentrations in hydrogen storage systems are essential for the ...mass-production of fuel-cell vehicles and, more broadly, for the transition to the hydrogen economy. Whereas several competing sensor technologies are potentially suitable for this role, ultra-low fire-hazard, contactless and technically simple magneto-electronic sensors stand apart because they have been able to detect the presence of hydrogen gas in a range of hydrogen concentrations from 0.06% to 100% at atmospheric pressure with the response time approaching the industry gold standard of one second. This new kind of hydrogen sensors is the subject of this review article, where we inform the academic physics, chemistry, material science and engineering communities as well as industry researchers about the recent developments in the field of magneto-electronic hydrogen sensors, including those based on magneto-optical Kerr effect, anomalous Hall effect and Ferromagnetic Resonance with a special focus on Ferromagnetic Resonance (FMR) based devices. In particular, we present the physical foundations of magneto-electronic hydrogen sensors and we critically overview their advantages and disadvantages for applications in the vital areas of the safety of hydrogen-powered cars and hydrogen fuelling stations as well as hydrogen concentration meters, including those operating directly inside hydrogen-fuelled fuel cells. We believe that this review will be of interest to a broad readership, also facilitating the translation of research results into policy and practice.
As a test of general applicability, we use the recently proposed spin-wave delay line active-ring reservoir computer to perform the spoken digit recognition task. On this, classification accuracies ...of up to 93% are achieved. The tested device prototype employs improved spin wave transducers (antennas). Therefore, in addition, we also let the computer complete the short-term memory (STM) task and the parity check (PC) tasks, because the fading memory and nonlinearity are essential to reservoir computing performance. The resulting STM and PC capacities reach maximum values of 4.77 and 1.47 respectively.
Protein phase separation by low-complexity, intrinsically disordered domains generates membraneless organelles and links to neurodegeneration. Cellular prion protein (PrP
) contains such domains, ...causes spongiform degeneration, and is a receptor for Alzheimer's amyloid-β oligomers (Aβo). Here, we show that PrP
separates as a liquid phase, in which α-helical Thr become unfolded. At the cell surface, PrP
Lys residues interact with Aβo to create a hydrogel containing immobile Aβo and relatively mobile PrP
. The Aβo/PrP hydrogel has a well-defined stoichiometry and dissociates with excess Aβo. NMR studies of hydrogel PrP
reveal a distinct α-helical conformation for natively unfolded amino-terminal Gly and Ala residues. Aβo/PrP hydrogel traps signal-transducing mGluR5 on the plasma membrane. Recombinant PrP
extracts endogenous Aβo from human Alzheimer's soluble brain lysates into hydrogel, and a PrP
antagonist releases Aβo from endogenous brain hydrogel. Thus, coupled phase and conformational transitions of PrP
are driven by Aβ species from Alzheimer's disease.
Amyloid-beta (Abeta) oligomers are thought to trigger Alzheimer's disease pathophysiology. Cellular prion protein (PrP(C)) selectively binds oligomeric Abeta and can mediate Alzheimer's ...disease-related phenotypes. We examined the specificity, distribution and signaling of Abeta-PrP(C) complexes, seeking to understand how they might alter the function of NMDA receptors (NMDARs) in neurons. PrP(C) is enriched in postsynaptic densities, and Abeta-PrP(C) interaction leads to Fyn kinase activation. Soluble Abeta assemblies derived from the brains of individuals with Alzheimer's disease interacted with PrP(C) to activate Fyn. Abeta engagement of PrP(C)-Fyn signaling yielded phosphorylation of the NR2B subunit of NMDARs, which was coupled to an initial increase and then a loss of surface NMDARs. Abeta-induced dendritic spine loss and lactate dehydrogenase release required both PrP(C) and Fyn, and human familial Alzheimer's disease transgene-induced convulsive seizures did not occur in mice lacking PrP(C). These results delineate an Abeta oligomer signal transduction pathway that requires PrP(C) and Fyn to alter synaptic function, with deleterious consequences in Alzheimer's disease.
Soluble amyloid-? oligomers (A?o) trigger Alzheimer's disease (AD) pathophysiology and bind with high affinity to cellular prion protein (PrPC). At the postsynaptic density (PSD), extracellular A?o ...bound to lipid-anchored PrPCactivates intracellular Fyn kinase to disrupt synapses. Here, we screened transmembrane PSD proteins heterologously for the ability to couple A?o-PrPCwith Fyn. Only coexpression of the metabotropic glutamate receptor, mGluR5, allowed PrPC-bound A?o to activate Fyn. PrPCand mGluR5 interact physically, and cytoplasmic Fyn forms a complex with mGluR5. A?o-PrPCgenerates mGluR5-mediated increases of intracellular calcium inXenopusoocytes and in neurons, and the latter is also driven by human AD brain extracts. In addition, signaling by A?o-PrPC-mGluR5 complexes mediates eEF2 phosphorylation and dendritic spine loss. For mice expressing familial AD transgenes, mGluR5 antagonism reverses deficits in learning, memory, and synapse density. Thus, A?o-PrPCcomplexes at the neuronal surface activate mGluR5 to disrupt neuronal function.
Soluble Amyloid-β oligomers (Aβo) trigger Alzheimer’s disease (AD) pathophysiology and bind with high affinity to Cellular Prion Protein (PrP
C
). At the post-synaptic density (PSD), extracellular ...Aβo bound to lipid-anchored PrP
C
activates intracellular Fyn kinase to disrupt synapses. Here, we screened transmembrane PSD proteins heterologously for the ability to couple Aβo–PrP
C
with Fyn. Only co-expression of the metabotropic glutamate receptor, mGluR5, allowed PrP
C
-bound Aβo to activate Fyn. PrP
C
and mGluR5 interact physically, and cytoplasmic Fyn forms a complex with mGluR5. Aβo–PrP
C
generates mGluR5-mediated increases of intracellular calcium in
Xenopus
oocytes and in neurons, and the later is also driven by human AD brain extracts. In addition, signaling by Aβo–PrP
C
–mGluR5 complexes mediates eEF2 phosphorylation and dendritic spine loss. For mice expressing familial AD transgenes, mGluR5 antagonism reverses deficits in learning, memory and synapse density. Thus, Aβo–PrP
C
complexes at the neuronal surface activate mGluR5 to disrupt neuronal function.
Amyloid-beta (Aβ) oligomers are thought to trigger Alzheimer’s disease (AD) pathophysiology. Cellular Prion Protein (PrP
C
) selectively binds oligomeric Aβ and can mediate AD-related phenotypes. ...Here, we examined the specificity, distribution and signaling from Aβ/PrP complexes, seeking to explain how they might alter the function of NMDA receptors in neurons. PrP
C
is enriched in post-synaptic densities, and Aβ/PrP
C
interaction leads to Fyn kinase activation. Soluble Aβ assemblies derived from human AD brain interact with PrP
C
to activate Fyn. Aβ engagement of PrP
C
/Fyn signaling yields phosphorylation of the NR2B subunit of NMDA-receptors, which is coupled to an initial increase and then loss of surface NMDA-receptors. Aβ-induced LDH release and dendritic spine loss require both PrP
C
and Fyn, and human familial AD transgene-induced convulsive seizures do not occur in mice lacking PrP
C
. These results delineate an Aβ oligomer signal transduction pathway requiring PrP
C
and Fyn to alter synaptic function with relevance to AD.
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![Alzheimer amyloid-[beta] ol...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1097-6256/small "Alzheimer amyloid-[beta] oligomer bound to postsynaptic prion protein activates Fyn to impair neurons")