4,794 research outputs found
Tunable pulse delay and advancement in a coupled nanomechanical resonator-superconducting microwave cavity system
We theoretically study the transmission of a weak probe field under the
influence of a strong pump field in a coupled nanomechanical
resonator-superconducting microwave cavity system. Using the standard
input-output theory, we find that both pulse delay (slow light effect) and
advancement (fast light effect) of the probe field can appear in this coupled
system provided that we choose the suitable detuning of the pump field from
cavity resonance. The magnitude of the delay (advancement) can be tuned
continuously by adjusting the power of the pump field. This technique
demonstrates great potential in applications including microwave phase shifter
and delay line.Comment: 12pages, 3 figure
Soliton with a Pion Field in the Global Color Symmetry Model
We calculate the property of the global color symmetry model soliton with the
pion field being included explicitly. The calculated results indicate that the
pion field provides a strong attraction so that the eigen-energy of a quark and
the mass of a soliton reduce drastically, in contrast to those with only the
sigma field.Comment: 15 pages, 2 figure
Testing the viability of the interacting holographic dark energy model by using combined observational constraints
Using the data coming from the new 182 Gold type Ia supernova samples, the
shift parameter of the Cosmic Microwave Background given by the three-year
Wilkinson Microwave Anisotropy Probe observations, and the baryon acoustic
oscillation measurement from the Sloan Digital Sky Survey, and lookback
time measurements, we have performed a statistical joint analysis of the
interacting holographic dark energy model. Consistent parameter estimations
show us that the interacting holographic dark energy model is a viable
candidate to explain the observed acceleration of our universe.Comment: 15 pages, 9 figures, accepted for publication in JCA
Prototype Design and Feasibility Analysis for Self-Levitated Conveying
In order to avoid friction and scratching when conveying object, an acoustic levitation prototype was designed to verify the feasibility. The modal shapes and the forced harmonic shapes of the prototype are obtained by an ANSYS coupled field computation with a one-quarter symmetry model and the levitation capacity was assessed by the use of groups of simulation and physical testing. The simulation results showed that the pure flexural and mixed flexural wave shapes with different wave numbers existed at some specific frequency. The amplitude in the central point of an aluminum plate having four piezo-electric discs glued to the bottom surface was simulated for a frequency spectrum. The experimental results confirmed the theoretical results and the feasibility of the prototype and confirm that objects can be floated at several resonant frequencies under forced vibrating condition. The system can provide largest bearing capacity when both the piezoelectric disc and the plate resonances coincide
Molecular Diagnosis of Periprosthetic Joint Infection by Quantitative RT-PCR of Bacterial 16S Ribosomal RNA
The diagnosis of periprosthetic joint infection is sometimes straightforward with purulent discharge from the fistula tract communicating to the joint prosthesis. However it is often difficult to differentiate septic from aseptic loosening of prosthesis because of the high culture-negative rates in conventional microbiologic culture. This study used quantitative reverse transcription polymerase chain reaction (RT-qPCR) to amplify bacterial 16S ribosomal RNA in vitro and in 11 clinical samples. The in vitro analysis demonstrated that the RT-qPCR method was highly sensitive with the detection limit of bacterial 16S rRNA being 0.148âpg/ÎŒl. Clinical specimens were analyzed using the same protocol. The RT-qPCR was positive for bacterial detection in 8 culture-positive cases (including aerobic, anaerobic, and mycobacteria) and 2 culture-negative cases. It was negative in one case that the final diagnosis was confirmed without infection. The molecular diagnosis of bacterial infection using RT-qPCR to detect bacterial 16S rRNA around a prosthesis correlated well with the clinical findings. Based on the promising clinical results, we were attempting to differentiate bacterial species or drug-resistant strains by using species-specific primers and to detect the persistence of bacteria during the interim period before the second stage reimplantation in a larger scale of clinical subjects
Reduced Mortality With Antiplatelet Therapy Deescalation After Percutaneous Coronary Intervention in Acute Coronary Syndromes: A Meta-Analysis
Background:Antiplatelet therapy deescalation has been suggested as an alternative to standard treatment with potent dual antiplatelet therapy (DAPT) for 1 year in low bleeding risk patients with acute coronary syndromes undergoing percutaneous coronary intervention to mitigate the increased risk of bleeding. Whether this strategy preserves the ischemic and survival benefits of potent DAPT is uncertain. Methods:We performed a pairwise meta-analysis in patients with acute coronary syndrome undergoing percutaneous coronary intervention treated with either 1-year standard potent DAPT versus deescalation therapy (potent DAPT for 1-3 months followed by either reduced potency DAPT or ticagrelor monotherapy for up to 1 year). Randomized trials comparing standard DAPT versus deescalation therapy in patients with acute coronary syndrome undergoing percutaneous coronary intervention were searched through MEDLINE, EMBASE, Cochrane databases, and proceedings of international meetings. The primary end point was 1-year all-cause mortality. Results:The meta-analysis included 6 trials in which 20 837 patients were randomized to potent DAPT for 1 to 3 months followed by deescalation therapy for up to 1 year (n=10 392) or standard potent DAPT for 1 year (n=10 445). Deescalation therapy was associated with lower 1-year rates of all-cause mortality compared with standard therapy (odds ratio, 0.75 [95% CI, 0.59-0.95]; P=0.02). Deescalation therapy was also associated with lower rates of major bleeding (odds ratio, 0.59 [95% CI, 0.48-0.72]; P<0.0001), with no significant difference in major adverse cardiac events (major adverse cardiovascular events; odds ratio, 0.89 [95% CI, 0.77-1.04]; P=0.14). Conclusions:In low bleeding risk patients with acute coronary syndrome undergoing percutaneous coronary intervention, compared with 1-year of potent DAPT, antiplatelet therapy deescalation therapy after 1 to 3 months was associated with decreased mortality and major bleeding with similar rates of major adverse cardiovascular events
Studies on CuCe0.75Zr0.25Ox preparation using bacterial cellulose and its application in toluene complete oxidation
A series of CuCe0.75Zr0.25Ox catalysts (CCZ) were synthesized based on the environmentalâfriendly bacterial cellulose (BC) by using the solâgel method. The corresponding synthesis mechanism, physicochemical properties of the catalysts and catalytic performances for toluene oxidation were comprehensively studied. In the presence of BC without sugar, the CCZâA synthesized by ethanolâgel exhibits better catalytic activity than the CCZâW synthesized by waterâgel, which may be due to the different roles of BC in different solvents. However, it is worth noting that the graft copolymerization between BC and active metal (Ce4+, Cu2+) is the same process in both waterâgel and ethanolâgel. The activity of CCZâSW synthesized by waterâgel using BC with sugar is obviously higher than that of CCZâW and CCZâA. The temperature of complete degradation of toluene over CCZâSW is 205â°C, which is 35â°C lower than that of CCZâW. The results from BET, Raman and H2âTPR indicate that the larger the specific surface area, the more oxygen vacancies and better lowâtemperature reducibility, that are mainly responsible for the excellent activity of CCZâSW. The existence of sugar in BC could hinder the agglomeration of active metal particles during the calcination process. Combined with the results of inâ
situ DRIFT, the adsorbed toluene on the catalyst surface is oxidized into alkoxide, aldehydic and carboxylic acid species as intermediates before the complete oxidation into CO2 and H2O.
Recommended from our members
Target-directed motor imagery of the lower limb enhances event-related desynchronization
Event-related desynchronization/synchronization (ERD/S) is an electroencephalogram (EEG) feature widely used as control signals for Brain-Computer Interfaces (BCIs). Never- theless, the underlying neural mechanisms and functions of ERD/S are largely unknown, thus investigating them is crucial to improve the reliability of ERD/S-based BCIs. This study aimed to identify Motor Imagery (MI) conditions that enhance ERD/S. We investigated fol- lowing three questions: 1) whether target-directed MI affects ERD/S, 2) whether MI with sound imagery affects ERD/S, and 3) whether ERD/S has a body part dependency of MI. Nine participants took part in the experiments of four MI conditions; they were asked to imagine right foot dorsiflexion (F), right foot dorsiflexion and the sound of a bass drum when the sole touched the floor (FS), right leg extension (L), and right leg extension directed toward a soccer ball (LT). Statistical comparison revealed that there were significant differ- ences between conditions L and LT in beta-band ERD and conditions F and L in beta-band ERS. These results suggest that mental rehearsal of target-directed lower limb movement without real sensory stimuli can enhance beta-band ERD; furthermore, MI of foot dorsiflex- ion induces significantly larger beta-band ERS than that of leg extension. These findings could be exploited for the training of BCIs such as powered prosthetics for disabled person and neurorehabilitation system for stroke patients
- âŠ