498 research outputs found
Coupling Circuit Resonators Among Themselves and To Nitrogen-Vacancy Centers in Diamond
We propose a scheme to couple NV centers in diamond through coplanar
waveguide resonators. The central conductor of the resonator is split into
several pieces which are coupled strongly with each other via simple capacitive
junctions or superconducting Josephson junctions. The NV centers are then put
at the junctions. The discontinuity at the junctions induces a large local
magnetic field, with which the NV centers are strongly coupled to the circuit
resonator. The coupling strength between the resonator and the NV center is
of order of --30\unit{MHz}.Comment: 4 pages; 3 figures; several typos corrected; figure 1 regenerate
Large-Scale Schr\"odinger-Cat States and Majorana Bound States in Coupled Circuit-QED Systems
We have studied the low-lying excitations of a chain of coupled circuit-QED
systems, and report several intriguing properties of its two nearly degenerate
ground states. The ground states are Schr\"odinger cat states at a truly large
scale, involving maximal entanglement between the resonator and the qubit, and
are mathematically equivalent to Majorana bound states. With a suitable design
of physical qubits, they are protected against local fluctuations and
constitute a non-local qubit. Further, they can be probed and manipulated
coherently by attaching an empty resonator to one end of the circuit-QED chain.Comment: 5 pages; 2 figures; incorrect references corrected; typos correcte
Overexpression of phospholipase D enhances Bcl-2 expression by activating STAT3 through independent activation of ERK and p38MAPK in HeLa cells
AbstractThe purpose of this study was to identify the role of phospholipase D (PLD) isozymes in Bcl-2 expression. Overexpression of PLD1 or PLD2 increased Bcl-2 expression and phosphatidic acid (PA), the product of PLDs, also upregulated Bcl-2 expression. Treatment with PA activated the phospholipase A2 (PLA2)/Gi/ERK1/2, RhoA/Rho-associated kinase (ROCK)/p38 MAPK, and Rac1/p38 MAPK pathways. PA-induced phosphorylation of ERK1/2 was attenuated by a PLA2 inhibitor (mepacrine) and, a Gi protein inhibitor (pertussis toxin, PTX). On the other hand, p38 MAPK phosphorylation was attenuated by a dominant negative Rac1 and a specific Rho-kinase inhibitor (Y-27632). These results suggest that PLA2/Gi acts at the upstream of ERK1/2, while Rac1 and RhoA/ROCK act upstream of p38 MAPK. We next, tried to determine which transcription factor is involved in PLD-related Bcl-2 expression. When signal transducer and activator of transcription 3 (STAT3) activity was blocked by a STAT3 specific siRNA, PA-induced Bcl-2 expression was remarkably decreased, suggesting that STAT3 is an essential transcription factor linking PLD to Bcl-2 upregulation. Taken together, these findings indicate that PLD acts as an important regulator in Bcl-2 expression by activating STAT3 involving the phosphorylation of Ser727 through the PLA2/Gi/ERK1/2, RhoA/ROCK/p38 MAPK, and Rac1/p38 MAPK pathways
Variational study of a two-level system coupled to a harmonic oscillator in a ultrastrong coupling regime
The nonclassical behaviors of a two-level system coupled to a harmonic
oscillator is investigated in the ultrastrong coupling regime. We revisit the
variational solution of the ground state and find that the existing solution do
not account accurately for nonclassical effects such squeezing. We suggest a
new trial wave function and demonstrate that it has an excellent accuracy on
the quantum correlation effects as well as on energy.Comment: 4 pages; 3 figures; to appear in Phys. Rev.
Accounting Conservatism, Changes In Real Investment, And Analysts Earnings Forecasts
This study examines whether sell-side analysts fully incorporate into their earnings forecasts the joint effects between accounting conservatism and changes in real investment on the quality of current earnings. Our results indicate that sell-side analysts do not fully incorporate such effects when they forecast future earnings so that they overestimate (underestimate) future earnings when current earnings are inflated (depressed) by those effects. Thus, we conclude that sell-side analysts do not recognize fully the joint effects between accounting conservatism and real activity on the earnings quality and that they need to mitigate their bias to enhance market efficiency by providing investors with a good benchmark for their earnings expectation
Double-stranded RNA induces inflammatory gene expression in schwann cells: Implication in the Wallerian degeneration
Schwann cells play an important role in peripheral nerve regeneration. Upon neuronal injury, activated
Schwann cells clean up the myelin debris by phagocytosis, and promote neuronal survival and
axon outgrowth by secreting various neurotrophic factors. However, it is unclear how the nerve injury
induces Schwann cell activation. Recently, it was reported that certain cytoplasmic molecules, which
are secreted by cells undergoing necrotic cell death, induce immune cell activation via the toll-like
receptors (TLRs). This suggests that the TLRs expressed on Schwann cells may recognize nerve damage
by binding to the endogenous ligands secreted by the damaged nerve, thereby inducing Schwann cell
activation. Accordingly, this study was undertaken to examine the expression and the function of the
TLRs on primary Schwann cells and iSC, a rat Schwann cell line. The transcripts of TLR2, 3, 4, and
9 were detected on the primary Schwann cells as well as on iSC. The stimulation of iSC with poly
(I:C), a synthetic ligand for the TLR3, induced the expression of TNF-α and RANTES. In addition,
poly (I:C) stimulation induced the iNOS expression and nitric oxide secretion in iSC. These results
suggest that the TLRs may be involved in the inflammatory activation of Schwann cells, which is
observed during Wallerian degeneration after a peripheral nerve injury.This work was supported by the Korea Research Foundation
Grant (KRF-2003-003-E00178)
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