680 research outputs found

    Lower Bound of Concurrence Based on Positive Maps

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    We study the concurrence of arbitrary dimensional bipartite quantum systems. An explicit analytical lower bound of concurrence is obtained, which detects entanglement for some quantum states better than some well-known separability criteria, and improves the lower bounds such as from the PPT, realignment criteria and the Breuer's entanglement witness.Comment: 8 pages, 1 figur

    Triamcinolone acetonide acetate

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    In the crystal structure of the title compound [systematic name: 2-(4b-fluoro-5-hy­droxy-4a,6a,8,8-tetra­methyl-2-oxo-2,4a,4b,5,6,6a,9a,10,10a,10b,11,12-dodeca­hydro-7,9-dioxa­penta­leno[2,1-a]phenanthren-6b-yl)-2-oxoethyl acetate], C26H33FO7, the mol­ecules are connected by inter­molecular O—H⋯O hydrogen bonds into an infinite supra­molecular chain along the b axis. The mol­ecular framework consists of five condensed rings, including three six-membered rings and two five-membered rings. The cyclo­hexa-2,5-dienone ring is nearly planar [maximum deviation = 0.013 (3) Å], while the cyclo­hexane rings adopt chair conformations. The two five-membered rings, viz. cyclo­pentane and 1,3-dioxolane, display envelope conformations

    Study on Roadway Parameters of Broken Compound Roof of Gently Inclined Thick Coal Seam

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    AbstractThis paper through investigation of the geological conditions of Da’ Anshan's coal mine, according to the special of the broken compound roof on inclined thick coal seam, select the anchor suspension theory and composite beam theory, design the roadway support's anchor parameters, and apply the finite element software ADINA carry out simulation analysis, through the contrast of analysis and engineering data, proved that the design of support parameters is reasonably and practicable. The research has practical value and can guide similar projects

    Theoretical calculation of the ‘natural flock restoration’ time of a cotton comber

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    Based on the overhanging beam theory, the stress on the flock of a cotton comber has been analyzed, and the natural frequency of the ‘natural flock restoration’ is calculated in combination with energy method. Finally, a theoretical model of the ‘natural flock restoration’ time has been developed. The model illustrates that the ‘natural flock restoration’ time of a cotton comber is determined by cotton properties, combing process and mechanical structure. The established theoretical model corrects the previous calculation method for the ‘natural flock restoration’ time of a cotton comber. The finding provides information for the development of a new type of cotton comber with high velocity

    Dexamethasone combined with other antiemetics for prophylaxis after laparoscopic cholecystectomy

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    SummaryBackground/ObjectivePostoperative nausea and vomiting (PONV) is one of the most common and distressing adverse events after laparoscopic cholecystectomy (LC). A meta-analysis of randomized clinical trials (RCTs) was performed to determine the efficacy and safety of dexamethasone combined with other antiemetic in the prevention of PONV in patients undergoing LC.MethodsA systematic literature search was conducted to identify all relevant RCTs. The primary outcome was PONV in the early period (0–3 hours, 0–4 hours, or 0–6 hours), late period (>6 hours), and the overall period (0–24 hours).ResultsNine RCTs with a total of 1089 patients were included in the analysis. Pooled analysis showed that dexamethasone combined with other antiemetics provided significantly better prophylaxis than single antiemetics in the early period [odds ratio (OR): 0.34; 95% confidence interval (CI): 0.21–0.55; p < 0.001], late period (OR: 0.35; 95% CI: 0.22–0.57; p < 0.001), and the overall period (OR: 0.36; 95% CI: 0.27–0.49; p < 0.001). Correspondingly, rescue antiemetic usage was significantly less in the combination therapy group (OR: 0.22; 95% CI: 0.12–0.41; p < 0.001). The most frequently reported adverse events were headache, dizziness, and itching. The incidence of adverse events did not differ between the two groups.ConclusionDexamethasone combined with other antiemetics was significantly better than single antiemetics for prophylaxis of PONV in patients undergoing LC, without apparent side effects
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