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Efficient homing of antibody-secreting cells to the bone marrow requires RNA-binding protein ZFP36L1.
Cell migration relies on coordinated activity of chemotactic and guidance receptors. Here, we report a specific role for the RNA-binding protein ZFP36L1 in limiting the abundance of molecules involved in the homing of antibody-secreting cells (ASCs) to the bone marrow (BM). In the absence of ZFP36L1, ASCs build up in the spleen and the liver and show diminished accumulation in the BM. ZFP36L1 facilitates migration by directly regulating G protein-coupled receptor kinase 2 (GRK2) and the integrin chains α4 and β1 in splenic ASCs. Expression of CXCR4 and of the integrins α4 and β1 is differentially regulated on ASCs produced at the early and late stages of the immune response. Consequently, deletion of the Zfp36l1 gene has a stronger effect on BM accumulation of high-affinity ASCs formed late in the response. Thus, ZFP36L1 is an integral part of the regulatory network controlling gene expression during ASC homing
Gauge Conditions for the Constrained-WZNW--Toda Reductions
There is a constrained-WZNW--Toda theory for any simple Lie algebra equipped
with an integral gradation. It is explained how the different approaches to
these dynamical systems are related by gauge transformations. Combining Gauss
decompositions in relevent gauges, we unify formulae already derived, and
explictly determine the holomorphic expansion of the conformally reduced WZNW
solutions - whose restriction gives the solutions of the Toda equations. The
same takes place also for semi-integral gradations. Most of our conclusions are
also applicable to the affine Toda theories.Comment: 12 pages, no figure
Current induced decomposition of Abrikosov vortices in p-n layered superconductors and heterostructures
We describe the decomposition of Abrikosov vortices into decoupled pancake vortices in superconductors having both electron and hole charge carriers. We estimate the critical current of such a decomposition, at which a superconducting-normal state transition occurs, and find that it is very sensitive to the magnetic field and temperature. The effect can be observed in recently synthesized self-doped high-Tc layered superconductors with electrons and holes coexisting in different Cu-O planes and in artificial p-n superconductor heterostructures. The sensitivity of the critical current to a magnetic field may be used for sensors and detectors of a magnetic field, which can be built up from the superconductor heterostructures
Asymmetric long Josephson junction acting as a ratchet for a quantum field
We study the escape rate of flux quanta in a long Josephson junction having an asymmetric spatial inhomogeneous critical current density. Such a junction can behave as a ratchet when driven by an ac current in the presence of a magnetic field. This rectification gives rise to a dc voltage Vdc across the junction. The usual approach of particlelike tunneling cannot describe this rectification, and a quantum field theory description is required. We also show that, under specific conditions, the rectification direction, and consequently Vdc, can change its sign when varying the temperature T near the crossover temperature T* between the quantum and classical regimes
Stress-induced Artificial neuron spiking in Diffusive memristors
Diffusive memristors owing to their ability to emulate neurons spiking
behavior are competitive candidates for next-generation neuromorphic elements.
Current studies on diffusive memristors are largely based on memristors
deposited on rigid substrates that require the application of a constant
electrical field for their neuron-like spiking behavior. We report here Ag
nanoparticle-based diffusive memristor developed on a flexible PET film. The
flexibility of the memristor combined with an external impact results in the
deformation of the memristor which induces a change in capacitance in the
device. By changing the impact magnitude and time interval between consecutive
impacts, we are able to regulate the spiking frequency of our diffusive
memristor. We have proposed a mathematical model which demonstrates a good
qualitative agreement with the experiments and helps to explain the spiking
behavior of our diffusive memristors. These results indicate a potential
strategy to realize flexible and deformable memristive devices for the
development of next-generation in-memory computing sensors and AI technologies.Comment: 14 pages, 5 figure
The molecular basis for stability of heterochromatin-mediated silencing in mammals.
RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.The archetypal epigenetic phenomenon of position effect variegation (PEV) in Drosophila occurs when a gene is brought abnormally close to heterochromatin, resulting in stochastic silencing of the affected gene in a proportion of cells that would normally express it. PEV has been instrumental in unraveling epigenetic mechanisms. Using an in vivo mammalian model for PEV we have extensively investigated the molecular basis for heterochromatin-mediated gene silencing. Here we distinguish 'epigenetic effects' from other cellular differences by studying ex vivo cells that are identical, apart from the expression of the variegating gene which is silenced in a proportion of the cells. By separating cells according to transgene expression we show here that silencing appears to be associated with histone H3 lysine 9 trimethylation (H3K9me3), DNA methylation and the localization of the silenced gene to a specific nuclear compartment enriched in these modifications. In contrast, histone H3 acetylation (H3Ac) and lysine 4 di or tri methylation (H3K4me2/3) are the predominant modifications associated with expression where we see the gene in a euchromatic compartment. Interestingly, DNA methylation and inaccessibility, rather than H3K9me3, correlated most strongly with resistance to de-repression by cellular activation. These results have important implications for understanding the contribution of specific factors involved in the establishment and maintenance of gene silencing and activation in vivo.Peer Reviewe
Controlling Josephson dynamics by strong microwave fields
We observe several sharp changes in the slope of the current-voltage characteristics CVCs of thin-film
ramp-edge Josephson junctions between YBa2Cu3O7− and Nb when applying strong microwave fields. Such
behavior indicates an intriguing Josephson dynamics associated with the switching from a parametric excitation
regime induced by the magnetic field of the microwave via oscillations of the Josephson critical current to
an ac-current-excitation regime triggered by the electric field of the microwave. We propose a model, which
describes the observed features on the CVC in terms of microwave-induced multiple switching between
running and locked solutions of sine-Gordon equation
Interaction between Bacteriophage DMS3 and Host CRISPR Region Inhibits Group Behaviors of Pseudomonas aeruginosa
Bacteriophage infection has profound effects on bacterial biology. Clustered regular interspaced short palindromic repeats (CRISPRs) and cas (CRISPR-associated) genes are found in most archaea and many bacteria and have been reported to play a role in resistance to bacteriophage infection. We observed that lysogenic infection of Pseudomonas aeruginosa PA14 with bacteriophage DMS3 inhibits biofilm formation and swarming motility, both important bacterial group behaviors. This inhibition requires the CRISPR region in the host. Mutation or deletion of five of the six cas genes and one of the two CRISPRs in this region restored biofilm formation and swarming to DMS3 lysogenized strains. Our observations suggest a role for CRISPR regions in modifying the effects of lysogeny on P. aeruginosa
Lower hybrid current drive in the presence of electric field
A new one-dimensional approach to the lower hybrid current drive (LHCD) modelling in the presence of an inductive electric field is suggested in this paper. The approach is based on using time-dependent solutions of a well-known Fokker-Planck equation for the distribution function of fast electrons calculated concurrently with solving plasma transport equation in the Automated System for TRansport Analysis (ASTRA) [1]. A good agreement between experimental and modelling results is demonstrated for an FT-2 [2] plasma shot. Also new formulae for the steady-state solution of this kinetic equation are found
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