3,154 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
Vulnerability assessment for the hazards of crosswinds when vehicles cross a bridge deck
AbstractA new procedure to assess the crosswind hazard of operating a vehicle over a bridge deck has been developed using a probabilistic approach that utilizes long-term wind data at bridge sites as well as the aerodynamic properties of bridge decks and vehicles. The proposed procedure for safety assessment considers the probabilities of two accident types: sideslip and overturning. The vulnerability of vehicles to crosswinds is represented by the number of days for traffic control that would be required to secure vehicle safety over a period of one year. The distribution of wind speed over a bridge deck was estimated from a section model wind tunnel test. A sea-crossing bridge was selected as an example, and a series of case studies were performed to identify the influential factors affecting vehicle vulnerability to crosswinds: vehicle type and loaded weight, the position of a running vehicle over a bridge deck, the bridge alignment relative to the dominant wind direction, and vehicle speed
Insight into highly conserved H1 subtype-specific epitopes in influenza virus hemagglutinin
Influenza viruses continuously undergo antigenic changes with gradual accumulation of mutations in hemagglutinin (HA) that is a major determinant in subtype specificity. The identification of conserved epitopes within specific HA subtypes gives an important clue for developing new vaccines and diagnostics. We produced and characterized nine monoclonal antibodies that showed significant neutralizing activities against H1 subtype influenza viruses, and determined the complex structure of HA derived from a 2009 pandemic virus A/Korea/01/2009 (KR01) and the Fab fragment from H1-specific monoclonal antibody GC0587. The overall structure of the complex was essentially identical to the previously determined KR01 HA-Fab0757 complex structure. Both Fab0587 and Fab0757 recognize readily accessible head regions of HA, revealing broadly shared and conserved antigenic determinants among H1 subtypes. The beta-strands constituted by Ser110-Glu115 and Lys169-Lys170 form H1 epitopes with distinct conformations from those of H1 and H3 HA sites. In particular, Glu112, Glu115, Lys169, and Lys171 that are highly conserved among H1 subtype HAs have close contacts with HCDR3 and LCDR3. The differences between Fab0587 and Fab0757 complexes reside mainly in HCDR3 and LCDR3, providing distinct antigenic determinants specific for 1918 pdm influenza strain. Our results demonstrate a potential key neutralizing epitope important for H1 subtype specificity in influenza virus
Control Method Of Circulating Refrigerant Amount For Heat Pump System
A heat pump system requires proper refrigerant charge amount. Once refrigerant is charged into a heat pump system, its charge amount is fixed. For this reason, prediction of optimal refrigerant charge amount is very important in order to yield best performance. Too low charge amount degrades capacity of heat pump. On the other hand, excessive charge amount decreases coefficient of performance (COP). The optimal value of refrigerant charge amount highly depends on secondary fluid temperature conditions. Consequently, fixed charge amount of refrigerant in heat pump shows the best performance only at certain temperature condition. Several ideas have revealed to change charge amount of the heat pump system. One is to have an additional reservoir to store or release refrigerant which is attached to a heat pump system. This method may seem simple but to measure exact amount of refrigerant in reservoir, additional pressure transducer, temperature measurement device, level sensor and other apparatus are required that increase the cost of heat pump. Another idea is to have reservoir between condenser outlet and expansion device. Rajapaksha and Suen (2004) showed that existence of reservoir at this point helps improve capacity while reducing the system COP. In this study, a new method for refrigerant charge amount control technique is presented. It has very simple control logic and requires only a few additional cost factors; several valves and additional tubes are only required. This method is based on different refrigerant phase distribution at each point of inlet and outlet of components in heat pump system. In a simple cycle heat pump system, refrigerant at condenser outlet (before expansion device) is in a subcooled liquid state at high pressure, while refrigerant is in a superheated vapor state at evaporator outlet (before compressor inlet) at low pressure. This technique regulates refrigerant charge by holding some volume of refrigerant in the connecting tube of considerable volume installed between the condenser outlet and the evaporator outlet. Using several solenoid valves (on/off) desired amount of refrigerant can be stored into a volume provided by a connecting tube. This connected volume is referred as ‘stagnation volume’ (Vstag). When one of this installed valve is closed and the rest of the valves are open, certain amount of refrigerant is stored in the stagnation volume (Vstag) while operating heat pump system. If closed valve is adjacent to condenser outlet, charge amount to the heat pump system increases while the charge is reduced when the valve adjacent to evaporator outlet is closed. This method is numerically verified and there are very little variation of COP. Therefore, heat pump can be operated at optimized circulating amount of refrigerant in spite of the secondary fluid temperature variation during heating or cooling operation
DiffRef3D: A Diffusion-based Proposal Refinement Framework for 3D Object Detection
Denoising diffusion models show remarkable performances in generative tasks,
and their potential applications in perception tasks are gaining interest. In
this paper, we introduce a novel framework named DiffRef3D which adopts the
diffusion process on 3D object detection with point clouds for the first time.
Specifically, we formulate the proposal refinement stage of two-stage 3D object
detectors as a conditional diffusion process. During training, DiffRef3D
gradually adds noise to the residuals between proposals and target objects,
then applies the noisy residuals to proposals to generate hypotheses. The
refinement module utilizes these hypotheses to denoise the noisy residuals and
generate accurate box predictions. In the inference phase, DiffRef3D generates
initial hypotheses by sampling noise from a Gaussian distribution as residuals
and refines the hypotheses through iterative steps. DiffRef3D is a versatile
proposal refinement framework that consistently improves the performance of
existing 3D object detection models. We demonstrate the significance of
DiffRef3D through extensive experiments on the KITTI benchmark. Code will be
available
Fundamental Elements for Successful Performance of CT Colonography (Virtual Colonoscopy)
There are many factors affecting the successful performance of CT colonography (CTC). Adequate colonic cleansing and distention, the optimal CT technique and interpretation with using the newest CTC software by a trained reader will help ensure high accuracy for lesion detection. Fecal and fluid tagging may improve the diagnostic accuracy and allow for reduced bowel preparation. Automated carbon dioxide insufflation is more efficient and may be safer for colonic distention as compared to manual room air insufflation. CT scanning should use thin collimation of ≤3 mm with a reconstruction interval of ≤1.5 mm and a low radiation dose. There is not any one correct method for the interpretation of CTC; therefore, readers should be well-versed with both the primary 3D and 2D reviews. Polyps detected at CTC should be measured accurately and reported following the "polyp size-based" patient management system. The time-intensive nature of CTC and the limited resources for training radiologists appear to be the major barriers for implementing CTC in Korea
LEFT VENTRICULAR OUTFLOW TRACT OBSTRUCTION IMMEDIATELY AFTER EXERCISE IN PATIENTS WITH NON-OBSTRUCTIVE HYPERTROPHIC CARDIOMYOPATHY
A liquid metal encapsulation for analyzing porous nanomaterials by atom probe tomography
Analyzing porous (nano)materials by the atom probe tomography has been
notoriously difficult. The electrostatic pressure intensifies stress at voids
which results in premature failure of the specimen, and the electrostatic field
distribution near voids lead to aberrations that are difficult to predict. Here
we propose a new encapsulating method for a porous sample using a
low-melting-point Bi-In-Sn alloy, known as Fields metal. As a model porous
sample, we used single-crystalline wustite following direct hydrogen-reduced
into iron. The complete encapsulation is performed using in-situ heating on the
stage of the scanning-electron microscope up to approx. 70 Celsius. No visible
corrosion nor dissolution of the sample occurred. Subsequently specimens are
shaped by focused ion beam milling under cryogenic conditions at -190 Celsius.
The proposed approach is versatile, can be applied to provide good quality atom
probe datasets from microporous materials
Hypochoeris radicata attenuates LPS-induced inflammation by suppressing P38, ERK, and JNK phosphorylation in Raw 264.7 macrophages
Hypochoeris radicata, an invasive plant species, is a large and growing threat to ecosystem integrity on Jeju Island, a UNESCO
World Heritage site. Therefore, research into the utilization of H. radicata is important and urgently required in order to solve this invasive plant problem in Jeju Island. The broader aim of our research is to elucidate the biological activities of
H. radicata, which would facilitate the conversion of this invasive species into high value added products. The present study was undertaken to identify the pharmacological effects of H. radicata
flower on the production of inflammatory
mediators in macrophages. The results indicate that the ethyl acetate fraction of
H. radicata extract (HRF-EA) inhibited the production of pro-inflammatory molecules such as NO, iNOS, PGE2, and COX-2, and cytokines such as TNF-α, IL-1β, and IL-6 in LPS-stimulated RAW 264.7 cells. Furthermore, the phosphorylation of MAPKs such as p38, ERK, and JNK was suppressed by HRF-EA in a concentration-dependent manner. In addition, through HPLC and UPLC fingerprinting, luteolins were also identified and quantified as extract constituents. On the basis of these results, we suggest that
H. radicata may be considered possible anti-inflammatory candidates for pharmaceutical and/or cosmetic applications
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