3,132 research outputs found
Enhancing quantum entanglement for continuous variables by a coherent superposition of photon subtraction and addition
We investigate how the entanglement properties of a two-mode state can be
improved by performing a coherent superposition operation of photon subtraction
and addition, proposed by Lee and Nha [Phys. Rev. A 82, 053812 (2010)], on each
mode. We show that the degree of entanglement, the EPR-type correlation, and
the performance of quantum teleportation can be all enhanced for the output
state when the coherent operation is applied to a two-mode squeezed state. The
effects of the coherent operation are more prominent than those of the mere
photon subtraction and the addition particularly in the small squeezing regime,
whereas the optimal operation becomes the photon subtraction in the
large-squeezing regime.Comment: 6 pages, 6 figures, published versio
DivGraphPointer: A Graph Pointer Network for Extracting Diverse Keyphrases
Keyphrase extraction from documents is useful to a variety of applications
such as information retrieval and document summarization. This paper presents
an end-to-end method called DivGraphPointer for extracting a set of diversified
keyphrases from a document. DivGraphPointer combines the advantages of
traditional graph-based ranking methods and recent neural network-based
approaches. Specifically, given a document, a word graph is constructed from
the document based on word proximity and is encoded with graph convolutional
networks, which effectively capture document-level word salience by modeling
long-range dependency between words in the document and aggregating multiple
appearances of identical words into one node. Furthermore, we propose a
diversified point network to generate a set of diverse keyphrases out of the
word graph in the decoding process. Experimental results on five benchmark data
sets show that our proposed method significantly outperforms the existing
state-of-the-art approaches.Comment: Accepted to SIGIR 201
Quantum linear amplifier enhanced by photon subtraction and addition
A deterministic quantum amplifier inevitably adds noise to an amplified
signal due to the uncertainty principle in quantum physics. We here investigate
how a quantum-noise-limited amplifier can be improved by additionally employing
the photon subtraction, the photon addition, and a coherent superposition of
the two, thereby making a probabilistic, heralded, quantum amplifier. We show
that these operations can enhance the performance in amplifying a coherent
state in terms of intensity gain, fidelity, and phase uncertainty. In
particular, the photon subtraction turns out to be optimal for the fidelity and
the phase concentration among these elementary operations, while the photon
addition also provides a significant reduction in the phase uncertainty with
the largest gain effect.Comment: published version, 7 pages, 9 figure
Real-time bladder volume monitoring by the application of a new implantable bladder volume sensor for a small animal model
AbstractAlthough real-time monitoring of bladder volume together with intravesical pressure can provide more information for understanding the functional changes of the urinary bladder, it still entails difficulties in the accurate prediction of real-time bladder volume in urodynamic studies with small animal models. We studied a new implantable bladder volume monitoring device with eight rats. During cystometry, microelectrodes prepared by the microelectromechanical systems process were placed symmetrically on both lateral walls of the bladder, and the expanded bladder volume was calculated. Immunohistological study was done after 1 week and after 4 weeks to evaluate the biocompatibility of the microelectrode. From the point that infused saline volume into the bladder was higher than 0.6mL, estimated bladder volume was statistically correlated with the volume of saline injected (p<0.01). Additionally, the microelectromechanical system microelectrodes used in this study showed reliable biocompatibility. Therefore, the device can be used to evaluate changes in bladder volume in studies with small animals, and it may help to provide more information about functional changes in the bladder in laboratory studies. Furthermore, owing to its biocompatibility, the device could be chronically implanted in conscious ambulating animals, thus allowing a novel longitudinal study to be performed for a specific purpose
Curcumin induces stabilization of Nrf2 protein through Keap1 cysteine modification
The present study was aimed to investigate the effects of curcumin, a representative chemopreventive phytochemical with pronounced antioxidant and anti-inflammatory properties, on activation of Nrf2 and expression of its target protein heme oxygenase-1 (HO-1) in mouse skin in vivo and in cultured murine epidermal cells. Treatment of mouse epidermal JB6 cells with curcumin resulted in the induction of HO-1 expression, and this was abrogated in cells transiently transfected with Nrf2 siRNA. While curcumin treatment increased protein expression of Nrf2, it did not alter the steady-state level of the Nrf2 mRNA transcript. Treatment of cells with curcumin stabilized Nrf2 by inhibiting ubiquitination and subsequent 26S proteasomal degradation of this transcription factor. Tetrahydrocurcumin, a non-electrophilic analogue of curcumin that lacks the alpha,beta-unsaturated carbonyl group, failed to induce HO-1 expression as well as nuclear translocation of Nrf2 and its binding to the antioxidant/electrophile response elements. Cells transfected with a mutant Keap1 protein in which cysteine 151 (Cys151) is replaced by serine exhibited marked reduction in curcumin-induced Nrf2 transactivation. Mass spectrometric analysis revealed that curcumin binds to Keap1 Cys151, supporting that this amino acid is a critical target for curcumin modification of Keap1, which facilitates the liberation of Nrf2. Thus, it is likely that the alpha,beta-unsaturated carbonyl moiety of curcumin is essential for its binding to Keap1 and stabilization of Nrf2 by hampering ubiquitination and proteasomal degradation.
Efficient entanglement criteria beyond Gaussian limits using Gaussian measurements
We present a formalism to derive entanglement criteria beyond the Gaussian
regime that can be readily tested by only homodyne detection. The measured
observable is the Einstein-Podolsky-Rosen (EPR) correlation. Its arbitrary
functional form enables us to detect non-Gaussian entanglement even when an
entanglement test based on second-order moments fails. We illustrate the power
of our experimentally friendly criteria for a broad class of non-Gaussian
states under realistic conditions. We also show rigorously that quantum
teleportation for continuous variables employs a specific functional form of
EPR correlation.Comment: published version, 6 pages, 3 figures, including Supplemental
Materia
Predictive value of alpha-fetoprotein in the long-term risk of developing hepatocellular carcinoma in patients with hepatitis B virus infection--results from a clinic-based longitudinal cohort.
BACKGROUND: Although serum level of alpha-fetoprotein (AFP) has long been used to complement imaging tests in the screening and diagnosis of hepatocellular carcinoma (HCC), whether it can be used as a predictive marker of long-term risk for developing HCC in patients with hepatitis B virus (HBV) has not been extensively evaluated and thus remains controversial.
METHODS: We retrospectively conducted a clinic-based longitudinal cohort study including 617 Korean American patients with HBV who had been followed for up to 22 years (median follow-up time, 6.2 years) to evaluate the association between baseline serum AFP level and the long-term risk of HCC.
RESULTS: The median baseline AFP value of these patients was 3.8 ng/ml. Compared to patients with lower-than-median AFP value, those with higher-than-median baseline serum AFP had a significantly increased risk of developing HCC with a hazard ratio (HR) of 2.73 (95% confidence interval [CI] 1.25-5.99), independent of other major HCC risk factors. In addition, we calculated the cumulative incidence of HCC during different years of follow-up time by baseline serum AFP, and found that the cumulative incidence of HCC was significantly higher in HBV patients with high baseline serum AFP compared to those with low baseline serum AFP in each of the five follow-up time periods examined.
CONCLUSIONS: Our results indicated that AFP was a strong independent prospective predictor of long-term HCC risk in high-risk HBV patients. More targeted prevention and early detection of HCC may be considered for these patients
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