Seismic Response Analysis of Steel-Concrete Composite Frame Structures with URSP Connectors.

The uplift-restricted and slip-permitted (URSP) connector is a new type of connector used in steel-concrete composite structures that has been proven to improve the structural performance of negative moment regions. Since this connector changes the interface restraint between the slab and steel beam, there is an imperative to study the seismic performance of steel-concrete composite frame systems with this new type of connector. In this study, the dynamic behavior of composite frame structures with URSP connectors under seismic loads was numerically investigated. First, a beam-shell mixed model was used and complex interfaces of different connectors were considered while establishing a numerical model to conduct elasto-plastic time history analysis under various seismic loads. This numerical model was validated with the frame sub-assemblage experimental results of quasi-static cyclic tests. Second, the model analysis results of structures with URSP connectors were obtained and compared with those of traditional structures. Third, dynamic response results including roof displacement, inter-story displacement, and the distribution and failure modes of plastic hinges were analyzed and compared. The comparisons indicated that the arrangement of full-span URSP connectors had a non-negligible influence on the dynamic behavior of the systems. The arrangement increased the maximum inter-story displacement by 31.5% and induced adverse effects in certain cases, which is not suggested in the application of URSP connectors. The partial arrangement of URSP connectors had little influence on the dynamic behavior of the systems, and the frame systems still showed a good seismic performance, which was the same as the traditional composite structural system. These findings may promote the application of URSP connectors in composite structures.

Efficacy and Safety of Rivaroxaban versus Warfarin for the Treatment of Acute Pulmonary Embolism: A Real-World Study.

BACKGROUND: Pulmonary embolism (PE) is a life-threatening disease. Target-specific anticoagulant rivaroxaban is a direct factor Xa inhibitor that can be safely used without laboratory monitoring. OBJECTIVE: To investigate the efficacy and safety of rivaroxaban versus warfarin for the treatment of acute pulmonary thromboembolism in real-world clinical practice. METHOD: This was a semiretrospective, semiprospective, and real-world trial involving 128 patients with acute symptomatic pulmonary embolism with or without active tumor or frailty. We compared rivaroxaban to the standard therapy consisting of low-molecular-weight heparin combined with warfarin. The primary efficacy outcome was absorption of thrombus. The principal safety outcome was bleeding episode. RESULTS: There was no significant difference in thrombus absorption between rivaroxaban and standard therapy after 3-month treatment (P = 0.798, 95% confidence interval (CI) 0.686 to 1.336) or more than 6-month treatment (P = 0.534, 95% confidence interval (CI) 0.795 to 1.556). There was no decline in efficacy (including computed tomographic pulmonary angiography and recurrence) when the rivaroxaban dose was reduced to 10 mg once daily after 3 months of administration. The ratio of patients without bleeding was 48.84% for rivaroxaban and 19.05% for standard therapy (P = 0.001). There was no significant difference in rivaroxaban monotherapy subgroups (including frail patients, tumor patients, and thrombolysis or nonthrombolysis at intermediate-high-risk patients). CONCLUSION: In this real-world study, the efficacy and safety of rivaroxaban alone was not different to standard therapy for pulmonary emboli absorption. With an extension in treatment duration, the rivaroxaban regimen had a higher efficacy and safety than standard therapy and there was no decline in treatment efficacy when the rivaroxaban dose was reduced to 10 mg once daily.

Comparison of rivaroxaban mono-therapy and standard-therapy adjusted by CYP2C9 and VKORC1 genotypes in symptomatic pulmonary embolism.

RATIONALE: Pulmonary embolism (PE) is a life-threatening manifestation of venous thromboembolism. Rivaroxaban is an oral anticoagulant, which directly inhibits Factor Xa. The objective of the current study was, in comparison to the standard-therapy method, to investigate the potential of rivaroxaban to improve the treatment of patients with PE, and to reduce hemorrhage in the standard-therapy group through adjusting the dose of warfarin by CYP2C9 and VKORC1 genotypes. METHODS: Sixty-two PE patients with or without deep venous thrombosis (DVT) was randomized to rivaroxaban mono-therapy or standard-therapy with enoxaparin followed by vitamin K antagonist (VKA). Concentration of the anticoagulants was adjusted according to the results of CYP2C9 and VKORC1 genotypes in order to stabilize the international normalized rate (INR) at 2.0-3.0 range. Length of hospital stay at initial hospitalization was compared, therapeutic efficacy was examined by computed tomographic pulmonary angiography (CTPA) and ventilation/perfusion (V/Q) scan, and side-effect of anti-coagulants was monitored at 1-month, and 3- or 6-months follow-up check points. RESULTS: We found that, overall, patients who received rivaroxaban mono-therapy had a significantly shorter length of hospital stay compared with patients who received standard-therapy of enoxaparin followed by VKA (9.29±3.70 versus 11.38±3.12days, P=0.021). The therapeutic efficacy was of no marked difference between these two groups. However, after one month treatment, 50% (16/32) of the standard-therapy group had mild hemorrhage, which was significantly higher than that of rivaroxaban mono-therapy group (16.7%, 5/30, P=0.006). Moreover, a significantly higher rate in the standard-therapy group (22.2% versus 3.4%, P=0.032) was found after 3 or 6months therapy. Major bleeding was slightly but not significantly higher in the standard-therapy group than that in the rivaroxaban therapy group. In addition, 2 (6.3%) patients died from Life-threatening bleeding in the standard-therapy group. CONCLUSION: Findings of the current study suggested that rivaroxaban mono-therapy result in shorter hospital stay compared to the standard-therapy. Implication of CYP2C9 and VKORC1 genotypes in determining dose of warfarin, however, remains to be further examined in larger cohort studies.