No abstract

No abstract

Background: In mammals, multiciliated cells (MCCs) line the lumen of the trachea, oviduct, and brain ventricles, where they drive fluid flow across the epithelium. Each MCC population experiences vastly different local environments that may dictate differences in their lifetime and turnover rates. However, with the exception of MCCs in the trachea, the turnover rates of these multiciliated epithelial populations at extended time scales are not well described.Results: Here, using genetic lineage-labeling techniques we provide a direct comparison of turnover rates of MCCs in these three different tissues. Conclusion:We find that oviduct turnover is similar to that in the airway (~6 months), while multiciliated ependymal cells turnover more slowly.

The adult uterus regenerates in the human during the menstrual cycle, and remodels in the mouse during the estrous cycle. Decades of work has demonstrated that this process is controlled by cycling steroid hormones, estrogen and progesterone. However, downstream signaling pathways that link hormonal action to this regeneration and remodeling are yet to be identified in the cycling uterus. We set out to identify these pathways, with the overarching hypothesis that developmental signaling pathways are redeployed in the adult uterus to control remodeling in the mouse. We were surprised to find that the majority of Hedgehog signaling components were transcriptionally co-regulated throughout the estrous cycle. To test the role of Hh signaling in cyclical uterine remodeling, we conditionally knocked out the major activator of the pathway, smoothened (Smo) using the progesterone receptor cre (PR-Cre). In the absence of Hh signaling, the uterus no longer remodels throughout the estrous cycle. We also show that the smooth muscle fibers of the uterus are significantly larger in the conditional knockouts compared to the controls suggesting hypertrophy of the smooth muscle. Our findings support the possibility that this smooth muscle homeostasis may underlie important aspects of uterine function such as contractility during late-stage pregnancy or the development of uterine smooth muscle tumors.

Corrective feedback has received much attention in language teaching and learning, including English as a foreign language. However, little research has been done with regard to college teachers’ perceptions about this area of interest in speaking language classes. The present study, therefore, focuses on teachers’ perceptions about oral corrective feedback and its types at tertiary contexts within a local province of the Mekong Delta, Vietnam. This paper draws on data collected as part of a larger study consisting of questionnaires. The findings indicate that teachers had positive perceptions about oral corrective feedback. However, some considered oral corrective feedback as optional since they were concerned with learners’ uptake when provided with corrective feedback. Elicitation was the most favored technique, followed by meta-linguistic feedback. Furthermore, implications are also presented. <p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/edu_01/0629/a.php" alt="Hit counter" /></p>