6,856 research outputs found
Normal forms and entanglement measures for multipartite quantum states
A general mathematical framework is presented to describe local equivalence
classes of multipartite quantum states under the action of local unitary and
local filtering operations. This yields multipartite generalizations of the
singular value decomposition. The analysis naturally leads to the introduction
of entanglement measures quantifying the multipartite entanglement (as
generalizations of the concurrence and the 3-tangle), and the optimal local
filtering operations maximizing these entanglement monotones are obtained.
Moreover a natural extension of the definition of GHZ-states to e.g. systems is obtained.Comment: Proof of uniqueness of normal form adde
Magnetization and EPR studies of the single molecule magnet Ni with integrated sensors
Integrated magnetic sensors that allow simultaneous EPR and magnetization
measurements have been developed to study single molecule magnets. A high
frequency microstrip resonator has been integrated with a micro-Hall effect
magnetometer. EPR spectroscopy is used to determine the energy splitting
between the low lying spin-states of a Ni single crystal, with an S=4
ground state, as a function of applied fields, both longitudinal and transverse
to the easy axis at 0.4 K. Concurrent magnetization measurements show changes
in spin-population associated with microwave absorption. Such studies enable
determination of the energy relaxation time of the spin system.Comment: 4 pages, 4 figures, accepted for publication (Proceedings of the 10th
Joint MMM/Intermag Conference, which will be published as special issues of
the Journal of Applied Physics
Targeting tauopathy with engineered tau-degrading intrabodies
BACKGROUND: The accumulation of pathological tau is the main component of neurofibrillary tangles and other tau aggregates in several neurodegenerative diseases, referred to as tauopathies. Recently, immunotherapeutic approaches targeting tau have been demonstrated to be beneficial in decreasing tauopathy in animal models. We previously found that passive immunotherapy with anti-tau antibody to human tau or expression of an anti-tau secreted single-chain variable fragment (scFv) in the central nervous system of a mouse model of tauopathy decreased but did not remove all tau-associated pathology. Although these and other studies demonstrate that conventional immunotherapeutic approaches targeting tau can influence tau pathogenesis, the majority of pathological tau remains in the cytosol of cells, not typically accessible to an extracellular antibody. Therefore, we reasoned targeting intracellular tau might be more efficacious in preventing or decreasing tauopathy.
METHODS: By utilizing our anti-tau scFv, we generated anti-tau intrabodies for the expression in the cytosol of neurons. To enhance the degradation capacity of conventional intrabodies, we engineered chimeric anti-tau intrabodies fused to ubiquitin harboring distinct mutations that shuttle intracellular tau for either the proteasome or lysosomal mediated degradation. To evaluate the efficacy in delaying or eliminating tauopathy, we expressed our tau degrading intrabodies or controls in human tau transgenic mice by adeno-associated virus prior to overt tau pathology and after tau deposition.
RESULTS: Our results demonstrate, the expression of chimeric anti-tau intrabodies significantly reduce tau protein levels in primary neuronal cultures expression human tau relative to a non-modified anti-tau intrabody. We found the expression of engineered tau-degrading intrabodies destined for proteasomal-mediated degradation are more effective in delaying or eliminating tauopathy than a conventional intrabody in aged human tau transgenic mice.
CONCLUSION: This study, harnesses the strength of intrabodies that are amendable for targeting specific domains or modifications with the cell-intrinsic mechanisms that regulate protein degradation providing a new immunotherapeutic approach with potentially improved efficacy
Green consumer markets in the fight against climate change
Climate change has become one of the greatest threats to environmental security, as attested by the growing frequency of severe flooding and storms, extreme temperatures and droughts. Accordingly, the European Unionâs (EU) 6th Environment Action Programme (2010) lists tackling climate change as its first priority. A key aim of the EU has been to cut CO2 emissions, a major factor in climate change, by 8% until 2012 and 20% until 2020. The European Commission has proposed the encouragement of private consumer market for green products and services as one of several solutions to this problem. However, existing research suggests that the market share of these products has been only 3%, although 30% of individuals favour environmental and ethical goods. This article uses Public Goods Theory to explain why the contribution of the green consumer market to fighting climate change has been and possibly may remain limited without further public intervention
Electrons in a ferromagnetic metal with a domain wall
We present theoretical description of conduction electrons interacting with a
domain wall in ferromagnetic metals. The description takes into account
interaction between electrons. Within the semiclassical approximation we
calculate the spin and charge distributions, particularly their modification by
the domain wall. In the same approximation we calculate local transport
characteristics, including relaxation times and charge and spin conductivities.
It is shown that these parameters are significantly modified near the wall and
this modification depends on electron-electron interaction.Comment: 10 pages with 4 figure
Ballistic and diffuse transport through a ferromagnetic domain wall
We study transport through ballistic and diffuse ferromagnetic domain walls
in a two-band Stoner model with a rotating magnetization direction. For a
ballistic domain wall, the change in the conductance due to the domain wall
scattering is obtained from an adiabatic approximation valid when the length of
the domain wall is much longer than the Fermi wavelength. In diffuse systems,
the change in the resistivity is calculated using a diagrammatic technique to
the lowest order in the domain wall scattering and taking into account
spin-dependent scattering lifetimes and screening of the domain wall potential.Comment: 9 pages, 3 figures, to appear in Phys. Rev.
Are There Quantum Effects Coming from Outside Space-time? Nonlocality, free will and "no many-worlds"
Observing the violation of Bell's inequality tells us something about all
possible future theories: they must all predict nonlocal correlations. Hence
Nature is nonlocal. After an elementary introduction to nonlocality and a brief
review of some recent experiments, I argue that Nature's nonlocality together
with the existence of free will is incompatible with the many-worlds view of
quantum physics.Comment: Talk presented at the meeting "Is Science Compatible with Our Desire
for Freedom?" organised by the Social Trends Institute at the IESE Business
School in Barcelona, Octobre 201
Relativistic quantum coin tossing
A relativistic quantum information exchange protocol is proposed allowing two
distant users to realize ``coin tossing'' procedure. The protocol is based on
the point that in relativistic quantum theory reliable distinguishing between
the two orthogonal states generally requires a finite time depending on the
structure of these states.Comment: 6 pages, no figure
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