Background: The inflammatory reaction is the main cause of acute respiratory distress syndrome and multiple organ failure in patients with Coronavirus disease 2019, especially those with severe and critical illness. Several studies suggested that high-dose vitamin C reduced inflammatory reaction associated with sepsis and acute respiratory distress syndrome. This study aimed to determine the efficacy and safety of high-dose vitamin C in Coronavirus disease 2019. Methods: We included 76 patients with Coronavirus disease 2019, classified into the high-dose vitamin C group (loading dose of 6g intravenous infusion per 12 hr on the first day, and 6g once for the following 4 days, n=46) and the standard therapy group (standard therapy alone, n=30). Results: The risk of 28-day mortality was reduced for the high-dose vitamin C versus the standard therapy group (HR=0.14, 95% CI, 0.03-0.72). Oxygen support status was improved more with high-dose vitamin C than standard therapy (63.9% vs 36.1%). No safety events were associated with high-dose vitamin C therapy. Conclusion: High-dose vitamin C may reduce the mortality and improve oxygen support status in patients with Coronavirus disease 2019 without adverse events.

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Flexoelectricity (FE) refers to the two-way coupling between strain gradients and the electric field in dielectric materials, and is universal compared to piezoelectricity, which is restricted to dielectrics with noncentralsymmetric crystalline structure. Involving strain gradients makes the phenomenon of flexoelectricity size dependent and more important for nanoscale applications. However, strain gradients involve higher order spatial derivate of displacements and bring difficulties to the solution of flexoelectric problems. This dilemma impedes the application of such universal phenomenon in multiple fields, such as sensors, actuators, and nanogenerators. In this study, we develop a mixed finite element method (FEM) for the study of problems with both strain gradient elasticity (SGE) and flexoelectricity being taken into account. To use C0 continuous elements in mixed FEM, the kinematic relationship between displacement field and its gradient is enforced by Lagrangian multipliers. Besides, four types of 2D mixed finite elements are developed to study the flexoelectric effect. Verification as well as validation of the present mixed FEM is performed through comparing numerical results with analytical solutions for an infinite tube problem. Finally, mixed FEM is used to simulate the electromechanical behavior of a 2D block subjected to concentrated force or voltage. This study proves that the present mixed FEM is an effective tool to explore the electromechanical behaviors of materials with the consideration of flexoelectricity.

This paper aims to understand residential mobility in non-market economies by conducting a case study of Chinese cities, a socialist society in transition. It is argued that residential mobility in China is mainly triggered by changes in housing supply and housing qualification, both of which are determined by housing policies. Using a retrospective survey in 20 Chinese cities, it was found that while the overall mobility is low, it has fluctuated significantly over time with a recent rising trend, which corresponds to historical changes in housing policies. The longitudinal models show that while some factors such as change of marital status and work units have consistent effects on mobility over time, indicating the persistency of the socialist housing system, others such as housing tenure have different effects over time, demonstrating changes in the Chinese housing system. The results share some similarities with the Western models, yet they demonstrate significant differences despite recent market penetrations. A framework that emphasizes the roles of the state and housing policies, and their change over time is needed to better understand residential mobility in China.

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