Influence of intrinsic motivations on the continuity of scientific knowledge contribution to online knowledge-sharing platforms.

Scientific knowledge contribution to online knowledge-sharing platforms has long been regarded as instrumental behavior based on utilitarian considerations. Employing cognitive evaluation theory, this study examines scientific expert users' behavioral metrics to understand the factors responsible for users continuing to contribute their scientific knowledge for an extended period or a very short span. We found that expert users' intrinsic motivations, which has received little attention in recent studies, constitute an important indicator of sustained online scientific knowledge contribution. Furthermore, although social rewards fail to predict the continuity of scientific knowledge contribution, they prolong the duration of knowledge contribution by enhancing the intrinsic motivations of expert users. In conclusion, a self-reinforcement mechanism underlies the relationship of intrinsic motivation with social rewards, which governs continuous online scientific knowledge contribution behavior.

Arecoline, a major alkaloid of areca nut, inhibits p53, represses DNA repair, and triggers DNA damage response in human epithelial cells.

The International Agency for Research on Cancer declared that areca nut was carcinogenic to human. Areca nut is the main component of betel quid (BQ), which is commonly consumed in Asia. Epidemiological studies have shown that BQ chewing is a predominant risk factor for oral and pharyngeal cancers. It has been known that areca nut is genotoxic to human epithelial cells. However, the molecular and cellular mechanisms underlying areca nut-associated genotoxicity are not fully understood. Here we showed that arecoline, a major alkaloid of areca nut, might contribute to oral carcinogenesis through inhibiting p53 and DNA repair. We found, on the biological aspect, that arecoline could induce gamma-H2AX phosphorylation, a sensitive DNA damage marker, in KB, HEp-2, and 293 cells, suggesting that DNA damages were elicited by arecoline. This phenomenon was supported by the observations of arecoline-induced hyperphosphorylation of ATM, Nbs1, Chk1/2, p53, and Cdc25C, as well as G2/M cell cycle arrest, indicating that a cellular DNA damage response was activated. To explore the possible mechanism accounting for arecoline-elicited DNA damages, we found that arecoline could inhibit p53 by its expression and transactivation function. As a result, the expression of p53-regulated p21(WAF1) and the p53-activated DNA repair were repressed by arecoline. Finally, we showed that p53 mRNA transcripts were frequently down-regulated in BQ-associated oral cancer, suggesting that arecoline-mediated p53 inhibition might play a role in BQ-associated tumorigenesis.

Impaired cutaneous T-cell attracting chemokine elevation and adipose-derived stromal cell migration in a high-glucose environment cause poor diabetic wound healing.

Diabetic wound care is a major health care concern. The major cause of non-healing of wounds in patients with diabetes mellitus (DM) patients mainly involves poor glycemic control, which hinders the migration of progenitor cells including mesenchymal stem cells to the wound site. In this study, we introduced adipose-derived stromal cells (ADSCs) into wound sites and demonstrated that the local transplantation of ADSCs accelerated DM-related wound healing. Furthermore, the migration ability of ADSCs, which diminishes in a high-glucose environment, was partially restored by the exogenous replenishment of the cutaneous T-cell attracting chemokine (CTACK/CCL27). Our findings suggest that CTACK is a potential novel therapeutic target in DM-related wound healing.