RESUMEN
The importance of the far-field diffraction pattern (FFDP) for retroreflectors lies in its ability to describe the performance of retroreflectors commonly used for positioning or measurement in optical systems. We proposed a new, to the best of our knowledge, retroreflector structure integrating a metal-coated corner cube retroreflector (CCR) and a spiral phase plate (SPP) to produce an annular FFDP. We analyzed the propagation characteristics of the light beam traveling through this combination and described the mechanism underlying the generation of an annular FFDP. We developed a simulation program to calculate the far-field pattern for various critical parameters of the spiral phase CCR and experimentally demonstrated its annular FFDP.
RESUMEN
Human mobility restriction policies have been widely used to contain the coronavirus disease-19 (COVID-19). However, a critical question is how these policies affect individuals' behavioral and psychological well-being during and after confinement periods. Here, we analyze China's five most stringent city-level lockdowns in 2021, treating them as natural experiments that allow for examining behavioral changes in millions of people through smartphone application use. We made three fundamental observations. First, the use of physical and economic activity-related apps experienced a steep decline, yet apps that provide daily necessities maintained normal usage. Second, apps that fulfilled lower-level human needs, such as working, socializing, information seeking, and entertainment, saw an immediate and substantial increase in screen time. Those that satisfied higher-level needs, such as education, only attracted delayed attention. Third, human behaviors demonstrated resilience as most routines resumed after the lockdowns were lifted. Nonetheless, long-term lifestyle changes were observed, as significant numbers of people chose to continue working and learning online, becoming "digital residents." This study also demonstrates the capability of smartphone screen time analytics in the study of human behaviors. Supplementary Information: The online version contains supplementary material available at 10.1140/epjds/s13688-023-00391-9.
RESUMEN
BACKGROUND: Bronchiolitis obliterans is a fatal respiratory disease characterized by the obliteration of small airways. Mesenchymal stem cells (MSCs) is a promising candidate for cell-based therapy. OBJECTIVE: To evaluate the therapeutic effect of human umbilical cord-derived mesenchymal stem cells (HUC-MSCs) on a murine model of bronchiolitis obliterans like injury (BOLI). METHOD: The murine model of BOLI was established by administrating of diacetyl (DA) via intratracheal instillation. Treatment of HUC-MSCs or HUC-MSCs culture medium (HUC-MSCs-CM) was conducted in the BOLI model. RESULTS: The pathogenic manifestations, lung function, and the number of neutrophils were similar between the oropharyngeal inhalation DA group (OPI-DA), intratracheal instillation group (ITI-DA); however, less reduction of weight and higher survival rate were observed in ITI-DA groups. Compared with the control groups, the trend of weight loss was significantly reduced (p < .05), and the pulmonary function was significantly improved (p < .05) in HUC-MSCs and HUC-MSCs-CM groups. Masson staining and hematoxylin and eosin staining showed that the deposition of collagen around bronchioles and blood vessels is less and airway epithelial cells and basal cells in lung tissue repaired better in HUC-MSCs and HUC-MSCs-CM groups compared with the control groups. Immunofluorescence shows the expression of E-cadherin and cytokeratin 5 (CK-5) were significantly higher in HUC-MSCs and HUC-MSCs-CM groups compared with control groups, while HUC-MSCs themselves did not express E-cadherin or CK-5. The DiI label showed HUC-MSCs gradually reduced after 2 days in the bronchus and 4 days in bronchiole. CONCLUSION: HUC-MSCs could help to repair airway epithelial cells in a murine model of BOLI. It might be related to paracrine factors of HUC-MSCs.
