14,245 research outputs found
A new quasi-exactly solvable problem and its connection with an anharmonic oscillator
The two-dimensional hydrogen with a linear potential in a magnetic field is
solved by two different methods. Furthermore the connection between the model
and an anharmonic oscillator had been investigated by methods of KS
transformation
cAMP Pulsing of Denuded Mouse Oocytes Increases Meiotic Resumption Via Activation of AMP-activated Protein Kinase
cAMP plays a critical role in the control of oocyte maturation, as a high level of cAMP maintains oocyte arrest at the first meiotic prophase. Yet this study shows that pulsing meiotically arrested denuded oocytes (DO) with cAMP induces oocyte maturation through the activation of AMP-activated protein kinase (PRKA). Short-term (3 h) pulsing of meiotically arrested oocytes with forskolin, an adenyl cyclase (AC) activator, increased oocyte cAMP, led to elevated AMP, and induced oocyte meiotic resumption compared to oocytes continuously cultured in the control medium with or without forskolin. Western analysis showed that germinal vesicle (GV)-stage oocytes after forskolin pulsing contained increased levels of phospho-acetyl CoA carboxylase (pACACA), a primary substrate of PRKA. Pulsing oocytes with the phosphodiesterase (PDE)-sensitive cAMP analog, 8-bromo-cAMP (8-Br-cAMP), also increased pACACA and pPRKA levels in GV-stage oocytes and induced oocyte meiotic resumption. Moreover, the PRKA inhibitors, compound C and araA, prevented 8-Br-cAMP pulsing-induced maturation. The lack of effect on meiotic induction and PRKA activation when oocytes were pulsed with the PDE-resistant activators of cAMP-dependent protein kinase, Sp-cAMP-AM and Sp-5,6-DCI-cBIMPS, suggests that cAMP degradation is required for pulsing-induced maturation. Pulsing oocytes with the exchange protein directly activated by cAMP (Epac)-specific activator, 8-CPT-2′-O-Me-cAMP, had no stimulatory effect on oocyte maturation, suggesting Epac is not involved in the pulsing-induced maturation. Taken together, these data support the idea that a transient increase in oocyte cAMP can induce meiotic resumption via activation of PRKA
Berry's phase for coherent states of Landau levels
The Berry phases for coherent states and squeezed coherent states of Landau
levels are calculated. Coherent states of Landau levels are interpreted as a
result of a magnetic flux moved adiabatically from infinity to a finite place
on the plane. The Abelian Berry phase for coherent states of Landau levels is
an analog of the Aharonov- Bohm effect. Moreover, the non-Abelian Berry phase
is calculated for the adiabatic evolution of the magnetic field B.Comment: 4 pages, 1 figur
Interaction of RNA-binding protein HuR and miR-466i regulates GM-CSF expression.
Granulocyte-macrophage colony-stimulating factor (GM-CSF) produced by T helper 17 (Th17) cells plays an essential role in autoimmune diseases. Transcriptional regulation of Th17 cell differentiation has been extensively studied, but post-transcriptional regulation of Th17 cell differentiation has remained less well characterized. The RNA-binding protein HuR functions to promote the stability of target mRNAs via binding the AU-rich elements of the 3\u27 untranslated region (3\u27UTR) of numerous pro-inflammatory cytokines including IL-4, IL-13, IL-17 and TNF-α. However, whether HuR regulates GM-CSF expression in Th17 cells has not been fully investigated. Here we showed that HuR conditional knockout (KO) Th17 cells have decreased GM-CSF mRNA in comparison with wild-type (WT) Th17 cells, and that HuR binds directly to GM-CSF mRNA 3\u27UTR. Interestingly, HuR deficiency increased the levels of certain microRNA expression in Th17 cells; for example, miR-466i functioned to mediate GM-CSF and IL-17 mRNA decay, which was confirmed by in vitro luciferase assay. Furthermore, we found that HuR promoted Mxi1 expression to inhibit certain miRNA expression. Taken together, these findings indicate that interaction of HuR and miR-466i orchestrates GM-CSF expression in Th17 cells
Comparison and Design Optimization of a Five-Phase Flux-Switching PM Machine for In-Wheel Traction Applications
A comparative study of five-phase outer-rotor flux-switching permanent magnet (FSPM) machines with different topologies for in-wheel traction applications is presented in this paper. Those topologies include double-layer winding, single-layer winding, C-core, and E-core configurations. The electromagnetic performance in the low-speed region, the flux-weakening capability in the high-speed region, and the fault-tolerance capability are all investigated in detail. The results indicate that the E-core FSPM machine has performance advantages. Furthermore, two kinds of E-core FSPM machines with different stator and rotor pole combinations are optimized, respectively. In order to reduce the computational burden during the large-scale optimization process, a mathematical technique is developed based on the concept of computationally efficient finite-element analysis. While a differential evolution algorithm serves as a global search engine to target optimized designs. Subsequently, multiobjective tradeoffs are presented based on a Pareto-set for 20 000 candidate designs. Finally, an optimal design is prototyped, and some experimental results are given to confirm the validity of the simulation results in this paper
The substructure and halo population of the Double Cluster and Persei
In order to study the stellar population and possible substructures in the
outskirts of Double Cluster and Persei, we investigate using the
GAIA DR2 data a sky area of about 7.5 degrees in radius around the Double
Cluster cores. We identify member stars using various criteria, including their
kinematics (viz, proper motion), individual parallaxes, as well as photometric
properties. A total of 2186 member stars in the parameter space were identified
as members. Based on the spatial distribution of the member stars, we find an
extended halo structure of and Persei, about 6 - 8 times larger than
their core radii. We report the discovery of filamentary substructures
extending to about 200 pc away from the Double Cluster. The tangential
velocities of these distant substructures suggest that they are more likely to
be the remnants of primordial structures, instead of a tidally disrupted stream
from the cluster cores. Moreover, the internal kinematic analysis indicates
that halo stars seems to be experiencing a dynamic stretching in the RA
direction, while the impact of the core components is relatively negligible.
This work also suggests that the physical scale and internal motions of young
massive star clusters may be more complex than previously thought.Comment: 9 pagges, 9 figures, Accecpted to A&
Geometric interpretation for A-fidelity and its relation with Bures fidelity
A geometric interpretation for the A-fidelity between two states of a qubit
system is presented, which leads to an upper bound of the Bures fidelity. The
metrics defined based on the A-fidelity are studied by numerical method. An
alternative generalization of the A-fidelity, which has the same geometric
picture, to a -state quantum system is also discussed.Comment: 4 pages, 1 figure. Phys. Rev.
Entanglement Property and Monogamy Relation of Gerneralized Mixed W
We introduce a new class of multipartite entangled mixed states with pure
state decompositions of generalized W states, similar to Schmidt-correlated
states having generalized GHZ states in the pure state decomposition. The
entanglement and separability properties are studied according to PPT
operations. Monogamy relations linked to these states are also investigated.Comment: 8 page
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