1,434 research outputs found
"Of Mice and Measures": A Project to Improve How We Advance Duchenne Muscular Dystrophy Therapies to the Clinic
A new line of dystrophic mdx mice on the DBA/2J (D2) background has emerged as a candidate to study the efficacy of therapeutic approaches for Duchenne muscular dystrophy (DMD). These mice harbor genetic polymorphisms that appear to increase the severity of the dystropathology, with disease modifiers that also occur in DMD patients, making them attractive for efficacy studies and drug development. This workshop aimed at collecting and consolidating available data on the pathological features and the natural history of these new D2/mdx mice, for comparison with classic mdx mice and controls, and to identify gaps in information and their potential value. The overall aim is to establish guidance on how to best use the D2/mdx mouse model in preclinical studies
Interactions between the Nse3 and Nse4 Components of the SMC5-6 Complex Identify Evolutionarily Conserved Interactions between MAGE and EID Families
The SMC5-6 protein complex is involved in the cellular response to DNA damage. It is composed of 6-8 polypeptides, of which Nse1, Nse3 and Nse4 form a tight sub-complex. MAGEG1, the mammalian ortholog of Nse3, is the founding member of the MAGE (melanoma-associated antigen) protein family and Nse4 is related to the EID (E1A-like inhibitor of differentiation) family of transcriptional repressors.Using site-directed mutagenesis, protein-protein interaction analyses and molecular modelling, we have identified a conserved hydrophobic surface on the C-terminal domain of Nse3 that interacts with Nse4 and identified residues in its N-terminal domain that are essential for interaction with Nse1. We show that these interactions are conserved in the human orthologs. Furthermore, interaction of MAGEG1, the mammalian ortholog of Nse3, with NSE4b, one of the mammalian orthologs of Nse4, results in transcriptional co-activation of the nuclear receptor, steroidogenic factor 1 (SF1). In an examination of the evolutionary conservation of the Nse3-Nse4 interactions, we find that several MAGE proteins can interact with at least one of the NSE4/EID proteins.We have found that, despite the evolutionary diversification of the MAGE family, the characteristic hydrophobic surface shared by all MAGE proteins from yeast to humans mediates its binding to NSE4/EID proteins. Our work provides new insights into the interactions, evolution and functions of the enigmatic MAGE proteins
Quantum optical coherence can survive photon losses: a continuous-variable quantum erasure correcting code
A fundamental requirement for enabling fault-tolerant quantum information
processing is an efficient quantum error-correcting code (QECC) that robustly
protects the involved fragile quantum states from their environment. Just as
classical error-correcting codes are indispensible in today's information
technologies, it is believed that QECC will play a similarly crucial role in
tomorrow's quantum information systems. Here, we report on the first
experimental demonstration of a quantum erasure-correcting code that overcomes
the devastating effect of photon losses. Whereas {\it errors} translate, in an
information theoretic language, the noise affecting a transmission line, {\it
erasures} correspond to the in-line probabilistic loss of photons. Our quantum
code protects a four-mode entangled mesoscopic state of light against erasures,
and its associated encoding and decoding operations only require linear optics
and Gaussian resources. Since in-line attenuation is generally the strongest
limitation to quantum communication, much more than noise, such an
erasure-correcting code provides a new tool for establishing quantum optical
coherence over longer distances. We investigate two approaches for
circumventing in-line losses using this code, and demonstrate that both
approaches exhibit transmission fidelities beyond what is possible by classical
means.Comment: 5 pages, 4 figure
Entanglement distillation from Gaussian input states by coherent photon addition
The entanglement between Gaussian entangled states can be increased by
non-Gaussian operations. We design a new scheme named coherent photon addition,
which can coherently add one photon generated by spontaneous parametric down
conversation process to Gaussian quadrature-entangled light pulses created by a
non-degenerate optical parametric amplifier. This operation can increase the
entanglement of input two-mode Gaussian states as an entanglement distillation,
and provides us a new method of non-Gaussian operation. This scheme can also
help us to study the decoherence of adding one to two-mode Gaussian states from
coherent photon addition to normal photon addition.Comment: 5 pages, 1 figure
From quantum fusiliers to high-performance networks
Our objective was to design a quantum repeater capable of achieving one
million entangled pairs per second over a distance of 1000km. We failed, but
not by much. In this letter we will describe the series of developments that
permitted us to approach our goal. We will describe a mechanism that permits
the creation of entanglement between two qubits, connected by fibre, with
probability arbitrarily close to one and in constant time. This mechanism may
be extended to ensure that the entanglement has high fidelity without
compromising these properties. Finally, we describe how this may be used to
construct a quantum repeater that is capable of creating a linear quantum
network connecting two distant qubits with high fidelity. The creation rate is
shown to be a function of the maximum distance between two adjacent quantum
repeaters.Comment: 2 figures, Comments welcom
Carrier-mediated magnetoelectricity in complex oxide heterostructures
While tremendous success has been achieved to date in creating both single
phase and composite magnetoelectric materials, the quintessential
electric-field control of magnetism remains elusive. In this work, we
demonstrate a linear magnetoelectric effect which arises from a novel
carrier-mediated mechanism, and is a universal feature of the interface between
a dielectric and a spin-polarized metal. Using first-principles density
functional calculations, we illustrate this effect at the SrRuO/SrTiO
interface and describe its origin. To formally quantify the magnetic response
of such an interface to an applied electric field, we introduce and define the
concept of spin capacitance. In addition to its magnetoelectric and spin
capacitive behavior, the interface displays a spatial coexistence of magnetism
and dielectric polarization suggesting a route to a new type of interfacial
multiferroic
Recent advances on information transmission and storage assisted by noise
The interplay between nonlinear dynamic systems and noise has proved to be of
great relevance in several application areas. In this presentation, we focus on
the areas of information transmission and storage. We review some recent
results on information transmission through nonlinear channels assisted by
noise. We also present recent proposals of memory devices in which noise plays
an essential role. Finally, we discuss new results on the influence of noise in
memristors.Comment: To be published in "Theory and Applications of Nonlinear Dynamics:
Model and Design of Complex Systems", Proceedings of ICAND 2012 (Springer,
2014
Pressure dependent electronic properties of MgO polymorphs: A first-principles study of Compton profiles and autocorrelation functions
The first-principles periodic linear combination of atomic orbitals method
within the framework of density functional theory implemented in the CRYSTAL06
code has been applied to explore effect of pressure on the Compton profiles and
autocorrelation functions of MgO. Calculations are performed for the B1, B2,
B3, B4, B8_1 and h-MgO polymorphs of MgO to compute lattice constants and bulk
moduli. The isothermal enthalpy calculations predict that B4 to B8_1, h-MgO to
B8_1, B3 to B2, B4 to B2 and h-MgO to B2 transitions take place at 2, 9, 37, 42
and 64 GPa respectively. The high pressure transitions B8_1 to B2 and B1 to B2
are found to occur at 340 and 410 GPa respectively. The pressure dependent
changes are observed largely in the valence electrons Compton profiles whereas
core profiles are almost independent of the pressure in all MgO polymorphs.
Increase in pressure results in broadening of the valence Compton profiles. The
principal maxima in the second derivative of Compton profiles shifts towards
high momentum side in all structures. Reorganization of momentum density in the
B1 to B2 structural phase transition is seen in the first and second
derivatives before and after the transition pressure. Features of the
autocorrelation functions shift towards lower r side with increment in
pressure.Comment: 19 pages, 8 figures, accepted for publication in Journal of Materials
Scienc
Microtubules gate tau condensation to spatially regulate microtubule functions.
Tau is an abundant microtubule-associated protein in neurons. Tau aggregation into insoluble fibrils is a hallmark of Alzheimer's disease and other types of dementia1, yet the physiological state of tau molecules within cells remains unclear. Using single-molecule imaging, we directly observe that the microtubule lattice regulates reversible tau self-association, leading to localized, dynamic condensation of tau molecules on the microtubule surface. Tau condensates form selectively permissible barriers, spatially regulating the activity of microtubule-severing enzymes and the movement of molecular motors through their boundaries. We propose that reversible self-association of tau molecules, gated by the microtubule lattice, is an important mechanism of the biological functions of tau, and that oligomerization of tau is a common property shared between the physiological and disease-associated forms of the molecule
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