Factors influencing users’ post replying behavior in a senior online community: An empirical investigation

Senior online communities (SOCs) have become an important venue for older people to seek support and exchange information. While online community engagement has been well studied in the existing literature, few studies have explored how older adults behave in online communities.Therefore, drawing upon signaling theory, this study aims to investigate how different content-related and social-related signals influence users’ post replying behavior (i.e., reply to another user’s post) in SOCs. We collected 7486 health-related posts and 71,859 comments from one ofthe most popular Chinese SOCs, Keai (https://www.keai99.com). Information signals in the posts were operationalized using different techniques such as text mining and social network analysis. Results from negative binomial regression indicated that content-related signals (posts’ topic andlength) and social-related signals (authors’ position and centrality) were related to replying behavior. In addition, we revealed some differences between the effects of these signals on informational replies and emotional replies. More specifically, compared to posts mentioningtraditional Chinese medicine, posts mentioning western medicine received more informational replies, but less emotional replies. Original posts triggered more informational replies, whereas shared posts attracted more emotional replies. Average reply length was positively related toinformational replies, but negatively related to emotional replies. Considering the important role of SOCs in satisfying older adults’ social and informational needs, future research is needed to promote user social engagement in SOCs, thereby maintaining their sustainability

Nisin-loaded polydopamine/hydroxyapatite composites

Microbial contamination caused by bacterial adhesion and colonization onto the materials surfaces has long been a serious threat to human health. Thus, it is imperative to develop advanced antimicrobial materials for bio-applications. Here, a unique polydopamine/ hydroxyapatite/nisin (PDA/HAP/Nisin) composite with good bioactivities and enhanced antibacterial activities have been developed. The uniform PDA particles are first prepared via the dopamine self-polymerization in an alkaline water-ethanol mixed solvent. Due to the abundance surface catecholamine moieties, PDA particles can serve as the powerful templates for the in-situ mineralization of hydroxyapatite (HAP) in a simulated body fluid (SBF) solution, forming PDA/HAP composites. Transmission electron microscopy, scanning electron microscopy, transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction are used to investigate the morphology, surface composition, and crystalline structure of the PDA/HAP composites. These PDA/HAP composites are utilized as the reservoir for loading the antimicrobial peptide–nisin. Ultraviolet visible spectrophotometry analysis shows that PDA/HAP composites have exhibited a high loading capacity and a superior loading efficiency for nisin. The resulting PDA/HAP/Nisin composites are ideal antimicrobial biomaterials for bio-application because they exhibit not only a significant in vitro cytocompatibility to human embryonic kidney HEK293 T cells, but also the enhanced antibacterial activities against Staphylococcus aureus (Gram-positive bacteria). These advantageous properties of the PDA/HAP/Nisin composites allow them as the promising candidates for a broad range of bio-applications, e.g., drug delivery, implant engineering, and bio-scaffold.Peer reviewe

Towards truthful mechanisms for mobile crowdsourcing with dynamic smartphones

Stimulating participation from smartphone users is of paramount importance to mobile crowd sourcing systems and applications. A few incentive mechanisms have been proposed, but most of them have made the impractical assumption that smartphones remain static in the system and sensing tasks are known in advance. The existing mechanisms fail when being applied to the realistic scenario where smartphones dynamically arrive to the system and sensing tasks are submitted at random. It is particularly challenging to design an incentive mechanism for such a mobile crowd sourcing system, given dynamic smartphones, uncertain arrivals of tasks, strategic behaviors, and private information of smartphones. We propose two truthful auction mechanisms for two different cases of mobile crowd sourcing with dynamic smartphones. For the offline case, we design an optimal truthful mechanism with an optimal task allocation algorithm of polynomial-time computation complexity of O (n+γ)3, where n is the number of smartphones and γ is the number of sensing tasks. For the online case, we design a near-optimal truthful mechanism with an online task allocation algorithm that achieves a constant competitive ratio of 1\2. Rigorous theoretical analysis and extensive simulations have been performed, and the results demonstrate the proposed auction mechanisms achieve truthfulness, individual rationality, computational efficiency, and low overpayment

Exploring the landscape, hot topics, and trends of bariatric metabolic surgery with machine learning and bibliometric analysis

Background: This study aimed to analyze the landscape of publications on bariatric metabolic surgery through machine learning and help experts and scholars from various disciplines better understand bariatric metabolic surgery’s hot topics and trends. Methods: In January 2021, publications indexed in PubMed under the Medical Subject Headings (MeSH) term ‘Bariatric Surgery’ from 1946 to 2020 were downloaded. Python was used to extract publication dates, abstracts, and research topics from the metadata of publications for bibliometric evaluation. Descriptive statistical analysis, social network analysis (SNA), and topic modeling with latent Dirichlet allocation (LDA) were used to reveal bariatric metabolic surgery publication growth trends, landscape, and research topics. Results: A total of 21,798 records of bariatric metabolic surgery–related literature data were collected from PubMed. The number of publications indexed to bariatric metabolic surgery had expanded rapidly. Obesity Surgery and Surgery for Obesity and Related Diseases are currently the most published journals in bariatric metabolic surgery. The bariatric metabolic surgery research mainly included five topics: bariatric surgery intervention, clinical case management, basic research, body contour, and surgical risk study. Conclusion: Despite a rapid increase in bariatric metabolic surgery–related publications, few studies were still on quality of life, psychological status, and long-term follow-up. In addition, basic research has gradually increased, but the mechanism of bariatric metabolic surgery remains to be further studied. It is predicted that the above research fields may become potential hot topics in the future