Background and objective: This study examined the changes in the cultural trend of use for green infrastructure in Seoul due to COVID-19 pandemic. Methods: The subjects of this study are 8 sites of green infrastructure selected by type: Forested green infrastructure, Watershed green infrastructure, Park green infrastructure, Walkway green infrastructure. The data used for analysis was blog posts for a total of four years from August 1, 2016 to July 31, 2020. The analysis method was conducted keyword frequency analysis, topic modeling, and related keyword analysis. Results: The results of this study are as follows. First, the number of posts on green infrastructure has increased since COVID-19, especially forested green infrastructure and watershed green infrastructure with abundant naturalness and high openness. Second, the cultural trend keywords before and after COVID-19 changed from large-scale to small-scale, community-based to individual-based activities, and nondaily to daily culture. Third, after COVID-19, topics and keywords related to coronavirus showed that the cultural trends were reflected on appreciation, activities, and dailiness based on natural resources. In sum, the interest in green infrastructure in Seoul has increased after COVID-19. Also, the change of green infrastructure represents the increased demand for experience that reflects the need and expectation for nature. Conclusion: The new trend of green Infrastructure in the pandemic era should be considered in the the individual relaxations & activities.

BackgroundExploring the pathogenesis of femoral head necrosis and finding effective treatments have always been challenges faced by clinicians, and establishing suitable and reproducible experimental animal models of human disease is a prerequisite. The purpose of this study was to establish and validate the effect of steroid-induced ON model on femoral head osteocytes and bone microarchitecture, as an important indicator for the assessment of necrosis degree. MethodsThrough literature review, the common rabbit protocols were retrieved and summarized, and some improvements were made and implemented, such as methylpredinsolone(MPS) alone with or without lipopolysaccharide(LPS) and whether adjuvant surgical intervention. After a six-week induction period, the femoral heads were harvested and histologically assessed osteocyte changes that was divided three categories, alive(normal), dying(pyknotic nuclei) and dead(empty lacunae) and evaluated bone microarchitecture changes by using micro-ct.ResultsConsecutive high dose MPS(40mg/kg) with three times effectively reduced the proportion of normal osteocytes(78.99%±2.75 to 54.33%±7.92) in trabecular, simultaneously, increased pyknotic nuclei osteocytes(13.51%±2.3 to 36.07%±5.19) or empty lacunae (7.51%±1.65 to 9.59%±3.96). and for combination with LPS, the occurrence of ON was more pronounced in some samples, but a high mortality rate was also found that was 26.8%(11/41) within 24 hours after LPS(10μg/kg) injection. When adjuvant surgical intervention, changes were more obvious (normal osteocytes:41.59%±12.13 pyknotic nuclei:46.34%±9.24 and empty lacunae:12.03%±4.3). and the above methods had obvious negative effect on bone parameters on femoral head.ConclusionsSeveral consecutive high doses of steroid had certain degree of negative effect on the viability of femoral head osteocytes. And cutting off the supply vessel (ligamentum teres) is a direct and effective method that can lead to severe ONFH occurrence. This results can provide valuable experience and reference for future research on establishing models of necrosis of the femoral head with difference degrees.

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