Teacher misbehaviors as learning demotivators in college classrooms: A cross-cultural investigation in China, Germany, Japan, and the United States

The present study was designed to investigate teacher misbehaviors as learning demotivators across four cultures: the U.S., China, Germany, and Japan. Three major findings were reported: (1) teachers across cultures all were perceived to misbehave infrequently, with only slight variations found across cultures; (2) teachers across cultures were perceived to engage in similar misbehavior tendencies. Overall, incompetence was the most common form of teacher misbehaviors, and some of the most frequently reported teacher misbehaviors were similar across cultures; and (3) teacher misbehaviors were associated with learning demotivators pan-culturally and within each culture, but they differed in the magnitude as predictors, explaining 8%–39% of the variance in student demotivation across cultures. Among the three dimensions of teacher misbehaviors, incompetence was the greatest source of demotivation within and across cultures

Epigenetic inactivation of the premature aging Werner syndrome gene in human cancer

Werner syndrome (WS) is an inherited disorder characterized by premature onset of aging, genomic instability, and increased cancer incidence. The disease is caused by loss of function mutations of the WRN gene, a RecQ family member with both helicase and exonuclease activities. However, despite its putative tumor-suppressor function, little is known about the contribution of WRN to human sporadic malignancies. Here, we report that WRN function is abrogated in human cancer cells by transcriptional silencing associated with CpG island-promoter hypermethylation. We also show that, at the biochemical and cellular levels, the epigenetic inactivation of WRN leads to the loss of WRN-associated exonuclease activity and increased chromosomal instability and apoptosis induced by topoisomerase inhibitors. The described phenotype is reversed by the use of a DNA-demethylating agent or by the reintroduction of WRN into cancer cells displaying methylation-dependent silencing of WRN. Furthermore, the restoration of WRN expression induces tumor-suppressor-like features, such as reduced colony formation density and inhibition of tumor growth in nude mouse xenograft models. Screening a large collection of human primary tumors (n = 630) from different cell types revealed that WRN CpG island hypermethylation was a common event in epithelial and mesenchymal tumorigenesis. Most importantly, WRN hypermethylation in colorectal tumors was a predictor of good clinical response to the camptothecin analogue irinotecan, a topoisomerase inhibitor commonly used in the clinical setting for the treatment of this tumor type. These findings highlight the importance of WRN epigenetic inactivation in human cancer, leading to enhanced chromosomal instability and hypersensitivity to chemotherapeutic drugs