Abstract Changes in the cytoskeletal organization within cells can be characterized by large spatial and temporal variations in rheological properties of the cell (e.g., the complex shear modulus G∗). Although the ensemble variation in G∗ of single cells has been elucidated, the detailed temporal variation of G∗ remains unknown. In this study, we investigated how the rheological properties of individual fibroblast cells change under a spatially confined environment in which the cell translational motion is highly restricted and the whole cell shape remains unchanged. The temporal evolution of single-cell rheology was probed at the same measurement location within the cell, using atomic force microscopy-based oscillatory deformation. The measurements reveal that the temporal variation in the power-law rheology of cells is quantitatively consistent with the ensemble variation, indicating that the cell system satisfies an ergodic hypothesis in which the temporal statistics are identical to the ensemble statistics. The autocorrelation of G∗ implies that the cell mechanical state evolves in the ensemble of possible states with a characteristic timescale.

Abstract Background To relieve patients' financial burden, China has established three basic health insurances: Urban Employee Basic Medical Insurance (UEBMI), Urban Resident Basic Medical Insurance (URBMI), and the New Rural Cooperative Medical Scheme (NRCMS). However, because the insured rich have more opportunity to access health care, more subsidies might be paid to them rather than the poor. We analysed the income-related benefit equity of health insurance for patients with chronic diseases to investigate who benefits most from government health insurance in China. Methods We used data from the second phase of the China Health and Retirement Longitudinal Study (CHARLS), collected in 2013. Benefit incidence (use of inpatient care or not), benefit degree 1 (measured by subsidy paid by the basic health insurances for inpatients), and benefit degree 2 (measured by reimbursement paid by health insurances for all patients with chronic diseases, such as cancer, hypertension, and diabetes) were deployed to indicate the benefits from the health insurances. We used the decomposition of the concentration index to analyse income-related horizontal inequity of benefit incidence and benefit degree. Findings There were 9728 patients identified for the analysis. The benefit incidence for patients with chronic diseases were 15·42% for those covered by UEBMI, 11·99% for those covered by URBMI, and 12·73% for those covered by NRCMS, while the subsidies paid by the three health insurances for inpatients (benefit degree 1) were ¥6457, ¥3127, and ¥2718, respectively, and for patients with chronic diseases (benefit degree 2) were ¥860, ¥307, and ¥279, respectively. By decomposing the concentration index, the income-related horizontal inequities of benefit incidence were 0·0868 for UEBMI, 0·1904 for URBMI, and 0·1495 for NRCMS. The horizontal inequities of benefit degree 1 and benefit degree 2 were 0·1880 and 0·4194 for UEBMI, 0·1186 and 0·3764 for URBMI, and 0·0900 and 0·2862 for NRCMS. Interpretation With same health-care needs, high-income patients with chronic diseases benefit more than low-income patients in each of China's basic health insurances. Improvement of benefit equity should be a concern of health insurance policy development. Funding Research Program of Shaanxi Soft Science (2015KRM117), Shaanxi Provincial Youth Star of Science and Technology in 2016, Basic Scientific Research Funding of Xi'an Jiaotong University (SK2015007), National Program for Support of Top-Notch Young Professionals, China Medical Board (15-227).