Porphyromonas gingivalis gingipains induce a pro-inflammatory extracellular microenvironment : the role of PAR-2 and fibronectin.

Periodontitis is a chronic inflammatory disease that is characterized by severe tissue destruction of the gingiva and other tooth supporting structures; if left untreated, tooth loss and disintegration of the alveolar bone occurs. This chronic inflammatory state has been linked to other systemic diseases such as cardiovascular disease, diabetes, rheumatoid arthritis, and Alzheimer’s disease. Porphyromonas gingivalis is the major pathogenic microbe in periodontitis. The main virulence factors of P. gingivalis are the Arg-aa and Lys-aa gingipains, which are proteolytic enzymes implicated in a plethora of activities that allow P. gingivalis to subvert the human immune system in the oral cavity and cause host tissue destruction. Here, we report that Arg-aa gingipains, RgpB and HRgpA stimulate fibroblasts to express fibronectin, a glycoprotein associated with tissue injury and repair, through the transcription of its gene promoter in a dose and time dependent fashion. Interestingly, when using a protease activated receptor 2 antagonists, gingipain induced fibronectin promoter activity was attenuated. Furthermore, gingipains stimulate fibroblasts to produce a pro-inflammatory matrix triggering production of IL-6 and IL-8 by monocytes that correlated with fibronectin-EDA expression. Taken together, our data suggests Arg-gingipains act on host fibroblasts to produce fibronectin which, stimulates immune cell activation. Taken together, these data suggest that gingipains promote and environment that disrupts host homeostasis

How a trainee mathematics teacher develops teacher self-efficacy

This research contributes new understanding of how teacher self-efficacy is acquired and developed by a preservice teacher during a one-year programme of initial teacher education (ITE). Our findings are consistent with previous studies in confirming that self-efficacy is acquired through vicarious experience, verbal persuasion and mastery experience while being undermined by negative physiological and affective states. In this study, however, we consider three separate subdomains of teacher self-efficacy: efficacy in classroom management, efficacy in student engagement and efficacy in instructional strategies. Based on a qualitative analysis of a trainee’s weekly reflections, this research shows that efficacy development is phased, initially dominated by developing efficacy in classroom management and efficacy in student engagement and, only at a significantly later stage, in instructional strategies. This is an important contribution to understanding how trainee teachers develop professional efficacy. Based on these findings, we tentatively offer a new self-efficacy development trajectory framework which can be used to inform the development of ITE programmes or continuing professional development programmes

Theory of Drop Formation

We consider the motion of an axisymmetric column of Navier-Stokes fluid with a free surface. Due to surface tension, the thickness of the fluid neck goes to zero in finite time. After the singularity, the fluid consists of two halves, which constitute a unique continuation of the Navier-Stokes equation through the singular point. We calculate the asymptotic solutions of the Navier-Stokes equation, both before and after the singularity. The solutions have scaling form, characterized by universal exponents as well as universal scaling functions, which we compute without adjustable parameters