3,023 research outputs found
Enhanced quantum teleportation in the background of Schwarzschild spacetime by weak measurements
It is commonly believed that the fidelity of quantum teleportation in the
gravitational field would be degraded due to the heat up by the Hawking
radiation. In this paper, we point out that the Hawking effect could be
eliminated by the combined action of pre- and post-weak measurements, and thus
the teleportation fidelity is almost completely protected. It is intriguing to
notice that the enhancement of fidelity could not be attributed to the
improvement of entanglement, but rather to the probabilistic nature of weak
measurements. Our work extends the ability of weak measurements as a quantum
technique to battle against gravitational decoherence in relativistic quantum
information.Comment: 9 pages, 5 figures, comments are welcom
Enhancing teleportation of quantum Fisher information by partial measurements
The purport of quantum teleportation is to completely transfer information
from one party to another distant partner. However, from the perspective of
parameter estimation, it is the information carried by a particular parameter,
not the information of total quantum state that needs to be teleported. Due to
the inevitable noise in environment, we propose two schemes to enhance quantum
Fisher information (QFI) teleportation under amplitude damping noise with the
technique of partial measurements. We find that post partial measurement can
greatly enhance the teleported QFI, while the combination of prior partial
measurement and post partial measurement reversal could completely eliminate
the effect of decoherence. We show that, somewhat consequentially, enhancing
QFI teleportation is more economic than that of improving fidelity
teleportation. Our work extends the ability of partial measurements as a
quantum technique to battle decoherence in quantum information processing.Comment: Revised version, minor changes, accepted by Phys. Rev.
Protecting entanglement from correlated amplitude damping channel using weak measurement and quantum measurement reversal
Based on the quantum technique of weak measurement, we propose a scheme to
protect the entanglement from correlated amplitude damping decoherence. In
contrast to the results of memoryless amplitude damping channel, we show that
the memory effects play a significant role in the suppression of entanglement
sudden death and protection of entanglement under severe decoherence. Moreover,
we find that the initial entanglement could be drastically amplified by the
combination of weak measurement and quantum measurement reversal even under the
correlated amplitude damping channel. The underlying mechanism can be
attributed to the probabilistic nature of weak measurements.Comment: 11 pages, 5 figures, accepted by Quantum Information Processin
Cinnamic aldehyde treatment alleviates chronic unexpected stress-induced depressive-like behaviors via targeting cyclooxygenase-2 in mid-aged rats
Ethnopharmacological relevance: COX-2 has been considered as a potent molecular target for prevention and therapy of depression. However, a recent study showed that COX-2 inhibitor does not improve depressive symptoms in persons aged 70 and over. Therefore, whether treatments targeting COX-2 have a clinical efficacy in depression, especially elderly individuals, remains unclear. Cinnamic aldehyde is a major constituent of Cinnamomum cassia, which has exhibited excellent anti-inflammatory activities as a COX-2 inhibitor. To investigate the potential antidepressant effect of cinnamic aldehyde in mid-aged rats
Feasibility of improving cone-beam CT number consistency using a scatter correction algorithm.
The study was to explore the feasibility of improving cone-beam CT (CBCT) number (corresponding to the Hounsfield units in computed tomography) consistency using a scatter-correction algorithm, with the aim of using CBCT images for treatment planning with density correction. A scatter correction algorithm was applied to a Varian OBI CBCT and an Elekta XVI CBCT, and was evaluated for improving CBCT number consistency. CBCT numbers of phantom materials were compared between images with and without bolus, which introduced additional scatter, and with and without scatter correction processing. It was observed that CBCT numbers were different in the images with and without bolus in both CBCT studies, and the differences were reduced remarkably after scatter-correction processing. Results showed that CBCT number consistency was significantly improved by use of the scatter-correction algorithm
Half-Heusler Topological Insulators: A First-Principle Study with the Tran-Blaha Modified Becke-Johnson Density Functional
We systematically investigate the topological band structures of half-Heusler
compounds using first-principles calculations. The modified Becke-Johnson
exchange potential together with local density approximation for the
correlation potential (MBJLDA) has been used here to obtain accurate band
inversion strength and band order. Our results show that a large number of
half-Heusler compounds are candidates for three-dimensional topological
insulators. The difference between band structures obtained using the local
density approximation (LDA) and MBJLDA potential is also discussed.Comment: 5 figures, 1 tabl
Mathematical Model to Predict Preheating Time and Temperature Profile in Boxed-Heart Square Timber during Preheating
The objective of this study was to develop a two-dimensional mathematical model that can beused to calculate the heat transfer in larch boxed-heart square timber during the preheating process. The preheating time obtained with the calculations agreed with the experimental results. Both experiments and calculations indicated that it took about 6.5 h for the center of the timbers (120 mm thick 120 mm wide) to reach ambient temperature, suggesting that the model can be used to accurately estimate preheating times. During the preheating process, the simulated core temperature of the wood agreed with the experimental result. However, for the remaining locations, the relative error was rather large, with the value first increasing and then decreasing with time. Therefore, the model can only be used to accurately estimate temperature at the core region of the wood. Furthermore, the results suggested that MC had no significant effect on preheating time
Comparative Analysis of In situ Fibronectin Using ToF-SIMS, SPI-MS, and dropDESI-MS in a Microfluidic Reactor
Fibronectin is an important biomolecule due to its role in cell differentiation, growth, kinesis, and adhesion. Such biological responses are mediated through membrane recognition and signaling; where fibronectin is found. Studying the outer molecular surface of fibronectin allows deeper insight into the microbiological reactions that occur during these processes. In situ mass spectrometry analysis in aqueous solution accurately represents fibronectin’s chemical components, made possible by a vacuum compatible microfluidic reactor, SALVI (System for Analysis at the Liquid Vacuum Interface). SALVI was paired with the analytical tools: time-of-flight secondary ion mass spectrometer (ToF-SIMS), single photon ionization mass spectrometer (SPI-MS) and drop desorption electrospray ionization mass spectrometer (dropDESI-MS). ToF-SIMS employed a bismuth liquid metal ion beam. Positive and negative ion spectral plots were constructed and analyzed. The advanced light source (ALS) SPI-MS), using a synchrotron vacuum ultraviolet (VUV) light, elicited data depending on varying photoionization efficiencies (PIE). PIE plots were examined for the initial detection of photons of a mass to charge ratio (m/z), resulting in the determination of the ionization efficiency (IE) of a corresponding compound. Both ToF-SIMS and SPI-MS are surface tools, with ion beam impact no further than the second monolayer. DropDESI-MS, analyzed under ambient conditions, utilized a capillary connecting the electrode spray to the mass spectrometer. Charged microdroplets were used to introduce samples to the mass analyzer. Central masses (m/z) from all three apparatuses were identified to their most possible compounds or constituents, demonstrating complementary results. Mass identifications were based on literature survey and results from peer reviewed articles. Our results suggest the need for further research of organic compounds, like fibronectin, to understand their surface compositions in aqueous solution
Effects of Compound Danshen tablets on spatial cognition and expression of brain β-amyloid precursor protein in a rat model of alzheimer's disease
AbstractObjectiveTo observe the effects of Compound Danshen Tablets (CDST) on spatial cognition and expression of brain b-amyloid precursor protein (β-APP) in a rat model of Alzheimer's disease.MethodsThe rat model of Alzheimer's disease (AD) was established using D-galactose to cause subacute aging combined with Meynert nucleus damage. Rat behavior was monitored using the Morris water maze, and the expression of β-APP in rat brain tissue was detected via immunohistochemistry.ResultsCDST significantly improved spatial cognition and decreased β-APP expression in the cortex and hippocampus (P<0.05, P<0.01).ConclusionsCDST can significantly improve spatial cognition in a rat model of AD. This observation is possibly related to a reduction in β-APP expression in the rat brain
Enhancing the Chemical Mixture Methodology: Incorporating 20 Health Code Numbers
The Chemical Mixture Methodology (CMM) is used by the Department of Energy (DOE), its contractors, and other private and public organizations for emergency response planning. CMM assesses the potential health impacts on individuals that would result from exposure to an airborne mixture of hazardous chemicals. Health Code Numbers (HCNs) are assigned to each chemical based on the human organs targeted by exposure. In the current CMM, only the top 10 HCNs ranked by severity are included in each CMM analysis. This project focuses on assessing what happens when doubling the potential number of HCNs for each chemical that could be used in each CMM analysis. A total of 361 chemicals were used in our testing (the entire CMM database contains over 3000 chemicals). A set of 127 representative mixtures were prepared for our analysis. Three different concentration distributions (called “ideal”, “realistic”, and “same”) were used for each test mixture, providing us with a total of 381 test cases. CMM results were compared for all 381 test cases using both the 10-HCN approach and the 20-HCN approach. Only a slight difference was observed between the 10- and 20-HCN approaches. This slight difference suggests that the top 10-HCNs give good representation of the potential toxic health effects. This also indicates that it is impractical to incorporate the 20-HCN approach in a future version of the CMM. Therefore, effort should be directed to other aspects of the CMM development such as refining the nervous system effects or respiratory irritant effects in the near future
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