Use of Electronic Word of Mouth as Quality Metrics: A Comparison of Airline Reviews on Twitter and Skytrax

User-generated content (UGC) at online platforms serves as a critical data source in the service industry as it can be accessed in real-time and reflect customers’ changing focus on service aspects. Drawing upon the importance-performance analysis framework, we propose a methodology to derive service quality metrics by utilizing the heterogeneous sources of UGC with customized text mining techniques and examining the effectiveness of these quality metrics. UGC data related to major U.S. airlines were collected from non-social media (Skytrax) and social media platforms (Twitter) from 2014 to June 2019. The results suggest that the topic distributions and the UGC-derived weighted service quality (WSQ, which represents the weighted sentiment based on service aspects) significantly vary between the non-social media and social media platforms. In addition, the WSQ scores derived from two platforms are significant indicators of the objective service quality measurement (i.e., airline quality rating) with stronger predictive power from the social media derived WSQ score

Study on the visible-light-induced photokilling effect of nitrogen-doped TiO2 nanoparticles on cancer cells

Nitrogen-doped TiO2 (N-TiO2) nanoparticles were prepared by calcining the anatase TiO2 nanoparticles under ammonia atmosphere. The N-TiO2 showed higher absorbance in the visible region than the pure TiO2. The cytotoxicity and visible-light-induced phototoxicity of the pure- and N-TiO2 were examined for three types of cancer cell lines. No significant cytotoxicity was detected. However, the visible-light-induced photokilling effects on cells were observed. The survival fraction of the cells decreased with the increased incubation concentration of the nanoparticles. The cancer cells incubated with N-TiO2 were killed more effectively than that with the pure TiO2. The reactive oxygen species was found to play an important role on the photokilling effect for cells. Furthermore, the intracellular distributions of N-TiO2 nanoparticles were examined by laser scanning confocal microscopy. The co-localization of N-TiO2 nanoparticles with nuclei or Golgi complexes was observed. The aberrant nuclear morphologies such as micronuclei were detected after the N-TiO2-treated cells were irradiated by the visible light