Social media insights into spatio-temporal emotional responses to COVID-19 crisis.

The Coronavirus pandemic has presented multifaceted challenges in urban emotional well-being and mental health management. Our study presents a spatio-temporal sentiment mining (STSM) framework to address these challenges, focusing on the space-time geography and environmental psychology. This framework analyzes the distribution and trends of 6 categories of public sentiments in Shanghai during the COVID-19 crisis, considering the potential urban spatial influencing factors. The research specifically draws on social media data temporally coinciding with the spread of COVID-19 and the pre-trained language model RoBERTa-wwm-ext to classify public sentiment, in order to characterize the distribution and trends of dominant urban sentiment under the influence of epidemic at different phases. The interactions between urban geospatial features and sentiments are further modelled and explained using LightGBM algorithm and SHapley Additive exPlanations (SHAP) technique. The experimental findings reveal the subtle yet dynamic impact of the urban environment on the long-term spatial variation and trends of public sentiment under the epidemic, with green spaces and socio-economic status emerging as significant factors. Regions with higher permanent population consumption demonstrated more positive sentiments, underscoring the significance of socio-economic factors in urban planning and public health policy. This research offers the most extensive analysis to date on the influence of urban characteristics on public sentiment during Shanghai's epidemic life cycle also lays the groundwork for applying the STSM framework in future crises beyond COVID-19.

Recent Advances of Chitosan and its Derivatives in Biomedical Applications.

Chitosan is the second-most abundant natural polysaccharide. It has unique characteristics, such as biodegradability, biocompatibility, and non-toxicity. Due to the existence of its free amine group and hydroxyl groups on its backbone chain, chitosan can undergo further chemical modifications to generate Chitosan Derivatives (CDs) that permit additional biomedical functionality. Chitosan and CDs can be fabricated into various forms, including Nanoparticles (NPs), micelles, hydrogels, nanocomposites and nano-chelates. For these reasons, chitosan and CDs have found a tremendous variety of biomedical applications in recent years. This paper mainly presents the prominent applications of chitosan and CDs for cancer therapy/diagnosis, molecule biosensing, viral infection, and tissue engineering over the past five years. Moreover, future research directions on chitosan are also considered.