5,509 research outputs found

    Hadronic Molecular States Composed of Spin-323\over 2 Singly Charmed Baryons

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    We investigate the possible deuteron-like molecules composed of a pair of charmed spin-32\frac{3}{2} baryons, or one charmed baryon and one charmed antibaryon within the one-boson-exchange (OBE) model. For the spin singlet and triplet systems, we consider the couple channel effect between systems with different orbital angular momentum. Most of the systems have binding solutions. The couple channel effect plays a significant role in the formation of some loosely bound states. The possible molecular states of Ωc∗Ωc∗\Omega_c^*\Omega_c^* and Ωc∗Ωˉc∗\Omega_c^*\bar{\Omega}_c^* might be stable once produced.Comment: 18 pages, 7 figure

    Diagnostic Accuracy of CEUS LI-RADS for the Characterization of Liver Nodules 20 mm or Smaller in Patients at Risk for Hepatocellular Carcinoma.

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    Background: American College of Radiology contrast agent–enhanced US Liver Imaging Reporting and Data System (CEUS LI-RADS) was developed to improve the accuracy of hepatocellular carcinoma (HCC) diagnosis at contrast agent2enhanced US. However, to the knowledge of the authors, the diagnostic accuracy of the system in characterization of liver nodules 20 mm or smaller has not been fully evaluated. Purpose: To evaluate the diagnostic accuracy of CEUS LI-RADS in diagnosing HCC in liver nodules 20 mm or smaller in patients at risk for HCC. Materials and Methods: Between January 2015 and February 2018, consecutive patients at risk for HCC presenting with untreated liver nodules 20 mm or less were enrolled in this retrospective double-reader study. Each nodule was categorized according to the CEUS LI-RADS and World Federation for Ultrasound in Medicine and Biology (WFUMB)–European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) criteria. Diagnostic performance of CEUS LI-RADS and WFUMB-EFSUMB characterization was evaluated by using tissue histologic analysis, multiphase contrast-enhanced CT and MRI, and imaging follow-up as reference standard and compared by using McNemar test. Results: The study included 175 nodules (mean diameter, 16.1 mm 6 3.4) in 172 patients (mean age, 51.8 years 6 10.6; 136 men). The sensitivity of CEUS LR-5 versus WFUMB-EFSUMB criteria in diagnosing HCC was 73.3% (95% confidence inter-val [CI]: 63.8%, 81.5%) versus 88.6% (95% CI: 80.9%, 94%), respectively (P, .001). The specificity of CEUS LR-5 versus WFUMB-EFSUMB criteria was 97.1% (95% CI: 90.1%, 99.7%) versus 87.1% (95% CI: 77%, 94%), respectively (P = .02). No malignant lesions were found in CEUS LR-1 and LR-2 categories. Only two nodules (of 41; 5%, both HCC) were malignant in CEUS LR-3 category. The incidences of HCC in CEUS LR-4, LR-5, and LR-M were 48% (11 of 23), 98% (77 of 79), and 75% (15 of 20), respectively. Two of 175 (1.1%) histologic analysis2confirmed intrahepatic cholangiocarcinomas were categorized as CEUS LR-M by CEUS LI-RADS and misdiagnosed as HCC by WFUMB-EFSUMB criteria. Conclusion: The contrast-enhanced US Liver Imaging Reporting and Data System (CEUS LI-RADS) algorithm was an effective tool for characterization of small (≤20 mm) liver nodules in patients at risk for hepatocellular carcinoma (HCC). Compared with World Federation for Ultrasound in Medicine and Biology2European Federation of Societies for Ultrasound in Medicine and Biology criteria, CEUS LR-5 demonstrated higher specificity for diagnosing small HCCs with lower sensitivity

    Effects on the pore structure and permeability change by coke deposition during crude oil in-situ combustion

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    In-situ combustion(ISC) is an enhanced oil recovery technique to exploit the unconventional crude oil resources with high recovery efficiency. Great amount of reaction heat is released in-place by burning the solid residue, so-called coke at the combustion front with the temperature higher than 400℃. Significant open ISC questions include the effect of coke formation on the pore structure and permeability. Coke deposition reduces the permeability and increases the permeability heterogeneities which will affect the oxygen transport in the formation, thereby influencing the oxygen participating reactions downstream. However, the existing empirical or semi-empirical relationships are still questionable to model the permeability change due to coke deposition. In the study, a high temperature and high pressure experimental apparatus was constructed to physically simulate the coke formation during the ISC processes. Please download the full abstract below
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