284 research outputs found
Low magnetic field reversal of electric polarization in a Y-type hexaferrite
Magnetoelectric multiferroics in which ferroelectricity and magnetism coexist
have attracted extensive attention because they provide great opportunities for
the mutual control of electric polarization by magnetic fields and
magnetization by electric fields. From a practical point view, the main
challenge in this field is to find proper multiferroic materials with a high
operating temperature and great magnetoelectric sensitivity. Here we report on
the magnetically tunable ferroelectricity and the giant magnetoelectric
sensitivity up to 250 K in a Y-type hexaferrite, BaSrCoZnFe11AlO22. Not only
the magnitude but also the sign of electric polarization can be effectively
controlled by applying low magnetic fields (a few hundreds of Oe) that modifies
the spiral magnetic structures. The magnetically induced ferroelectricity is
stabilized even in zero magnetic field. Decayless reproducible flipping of
electric polarization by oscillating low magnetic fields is shown. The maximum
linear magnetoelectric coefficient reaches a high value of ~ 3.0\times10^3 ps/m
at 200 K.Comment: 9 pages, 5 figures, a couple of errors are correcte
Two-mode correlated multiphoton bundle emission
The preparation of correlated multiphoton sources is an important research
topic in quantum optics and quantum information science. Here, we study
two-mode correlated multiphoton bundle emission in a nondegenerate multiphoton
Jaynes-Cummings model, which is comprised of a two-level system coupled with
two cavity modes. The two-level system is driven by a near-resonant strong
laser such that the Mollow regime dominates the physical processes in this
system. Under certain resonance conditions, a perfect super-Rabi oscillation
between the zero-photon state and the
()-photon state of the two cavity modes can
take place. Induced by the photon decay, the two-mode correlated multiphoton
bundle emission occurs in this system. More importantly, the results show that
there is an antibunching effect between the strongly-correlated photon bundles,
so that the system behaves as an antibunched ()-photon source. The work
opens up a route towards achieving two-mode correlated multiphoton source
device, which has potential applications in modern quantum technology.Comment: 16 pages, 6 figures, to appear in Advanced Quantum Technologie
Amplifying Frequency Up-Converted Infrared Signals with a Molecular Optomechanical Cavity
Frequency up-conversion, enabled by molecular optomechanical coupling, has
recently emerged as a promising approach for converting infrared signals into
the visible range through quantum coherent conversion of signals. However,
detecting these converted signals poses a significant challenge due to their
inherently weak signal intensity. In this work, we propose an amplification
mechanism capable of enhancing the signal intensity by a factor of 1000 or more
in a molecular-cavity system consisting molecules. The mechanism takes
advantage of the strong coupling enhancement with molecular collective mode and
Stokes sideband pump. Our work demonstrates a feasible approach for
up-converting infrared signals to the visible range.Comment: 5 pages, 4 figures for the main text; 6 pages, 2 figures for
Supplementary Materia
steve bAccumulation of nerve growth factor and its receptors in the uterus and dorsal root ganglia in a mouse model of adenomyosis
<p>Abstract</p> <p>Background</p> <p>Adenomyosis is a common gynecological disease, which is accompanied by a series of immunological and neuroendocrinological changes. Nerve growth factor (NGF) plays a critical role in producing pain, neural plasticity, immunocyte aggregation and release of inflammatory factors. This study aimed to investigate the expression of NGF and its two receptors in uteri and dorsal root ganglia (DRG) in an adenomyosis mouse model, as well as their relationship with the severity of adenomyosis.</p> <p>Methods</p> <p>Forty newborn ICR mice were randomly divided into the adenomyosis model group and control group (n = 20 in each group). Mice in the adenomyosis model group were orally dosed with 2.7 μmol/kg tamoxifen on days 2-5 after birth. Experiments were conducted to identify the expression of NGF- beta and its receptors, tyrosine kinase receptor (trkA) and p75 neurotrophin receptor (p75NTR), in the uterus and DRG in four age groups (90+/-5 d, 140+/-5 d, 190+/-5 d and 240+/-5 d; n = 5 mice in each group) by western bolt, immunochemistry and real time reverse transcription-polymerase chain reaction.</p> <p>Results</p> <p>Adenomyosis, which became more serious as age increased, was successfully induced in dosed ICR mice. NGF-beta, trkA and p75NTR protein levels in the uterus and trkA mRNA levels in DRG were higher in the older aged adenomyosis model group than those in controls (190+/-5 d and 240+/-5 d groups, P < 0.05). The expression of NGF-beta and its receptors in the uterus increased gradually as age increased for adenomyosis mice (190+/-5 d and 240+/-5 d, P < 0.05, compared with 90+/-5 d) but it showed little change in control mice. The mRNA level of trkA in DRG also increased as age increased in the adenomyosis model group (190+/-5 d and 240+/-5 d, P < 0.05, compared with 90+/-5 d) but was unchanged in controls. The mRNA level of p75NTR in DRG was not different between the adenomyosis and control groups and was stable from young to old mice.</p> <p>Conclusions</p> <p>NGF- beta can be used as an indicator for the severity of adenomyosis. The gradually increasing level of NGF- beta and its receptors while the disease becomes more severe suggests an effect of NGF- beta on pathogenic mechanisms of adenomyosis.</p
Building Intelligent Communication Systems for Handicapped Aphasiacs
This paper presents an intelligent system allowing handicapped aphasiacs to perform basic communication tasks. It has the following three key features: (1) A 6-sensor data glove measures the finger gestures of a patient in terms of the bending degrees of his fingers. (2) A finger language recognition subsystem recognizes language components from the finger gestures. It employs multiple regression analysis to automatically extract proper finger features so that the recognition model can be fast and correctly constructed by a radial basis function neural network. (3) A coordinate-indexed virtual keyboard allows the users to directly access the letters on the keyboard at a practical speed. The system serves as a viable tool for natural and affordable communication for handicapped aphasiacs through continuous finger language input
Engulfing cells promote neuronal regeneration and remove neuronal debris through distinct biochemical functions of CED-1
Two important biological events happen coincidently soon after nerve injury in the peripheral nervous system in C. elegans: removal of axon debris and initiation of axon regeneration. But, it is not known how these two events are co-regulated. Mutants of ced-1, a homolog of Draper and MEGF10, display defects in both events. One model is that those events could be related. But our data suggest that they are actually separable. CED-1 functions in the muscle-type engulfing cells in both events and is enriched in muscle protrusions in close contact with axon debris and regenerating axons. Its two functions occur through distinct biochemical mechanisms; extracellular domain-mediated adhesion for regeneration and extracellular domain binding-induced intracellular domain signaling for debris removal. These studies identify CED-1 in engulfing cells as a receptor in debris removal but as an adhesion molecule in neuronal regeneration, and have important implications for understanding neural circuit repair after injury
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