In this study, we successfully grafted chitosan (CS) onto multi-walled carbon nanotubes (MWCNTs) to enhance their properties and potential applications in the biomedical field. FTIR spectroscopy confirmed the successful covalent bonding of CS onto MWCNTs, indicated by the new absorption peak of the amide bond (–CONH–). Thermal analysis showed that the modified MWCNTs (MWCNT-CS) had significant weight loss around 260 °C, suggesting the decomposition of hydroxypropyl chitosan, and confirming its presence in the nanocomposite. SEM images revealed that CS grafting improved the dispersibility of MWCNTs, a property crucial for their use as nanofillers in polymers. Moreover, the micro-tensile bond strength of dentin surface increased with increasing MWCNT-CS concentrations, indicating the potential of MWCNT-CS as a pretreatment for dentin bonding. After simulated aging, the bond strength remained significantly higher for MWCNT-CS groups compared to those without pretreatment. In biocompatibility assessment using the MTT assay, MWCNT-CS showed higher cell viability than MWCNT, suggesting improved biocompatibility after CS modification. The results of this study suggest that CS-modified MWCNTs could be promising materials for applications in dentin bonding, dentin mineralization, bone scaffolding, implants, and drug delivery systems.

Today, tens of millions of ethnic Chinese are scattered throughout Southeast Asia as a result of the massive influx of immigrants from China during the past several centuries. The present study analyzed the language attitude of the ethnic Chinese in Southeast Asia, focusing on four countries: Indonesia, Thailand, Malaysia, and Singapore. For this purpose, a total of 177 samples of language attitude questionnaire were collated. The questionnaire was composed of 11 language attitude-related elements in affective, behavioral, and cognitive components with respect to the multiple languages used in the countries: national language, English, local Chinese dialects, Mandarin, and others. Analysis of the data reveals intriguing findings about the language attitude of the ethnic Chinese in different countries. Both the similarities and the differences of language attitude are found among the ethnic Chinese groups in the Southeast Asian countries, reflecting the political, economic, and social situations of each country. The prospect of the local Chinese dialects look dim due to exogenous factors surrounding the linguistic ecosystems in the region.