Students’ knowledge about proof and handling proof

Research has highlighted that students’ have problems regarding mathematical proof. In part, these have been connected to deficits in their knowledge about proof and handling proof. However, empirical data on students’ knowledge about proof and handling proof throughout secondary education is so far missing. Further, it is unclear if there is a connection between concept- and action-oriented knowledge about proof and handling proof. To address these gaps, an empirical study was conducted, investigating the knowledge about proof and handling proof concerning proof principles of N = 456 students in grade 8 to 11. Results indicate that (i) only concept-oriented knowledge significantly increases throughout secondary education and (ii) there is only little relation between concept- and action-oriented knowledge

PHARMACOKINETICS OF N-(4-HYDROXYPHENYL)-aII- trans-RETINAMIDE IN RATS

ABSTRACT: The concentration of N-(4-hydroxyphenyl)-alItrans-retinamide (HPR) was determined in plasma and a variety of tissues from rats after an intravenous dose (5 mg/kg). The plasma concentrationtIme curve could be accurately described by a triexponentla

CD155/PVR plays a key role in cell motility during tumor cell invasion and migration

BACKGROUND: Invasion is an important early step of cancer metastasis that is not well understood. Developing therapeutics to limit metastasis requires the identification and validation of candidate proteins necessary for invasion and migration. METHODS: We developed a functional proteomic screen to identify mediators of tumor cell invasion. This screen couples Fluorophore Assisted Light Inactivation (FALI) to a scFv antibody library to systematically inactivate surface proteins expressed by human fibrosarcoma cells followed by a high-throughput assessment of transwell invasion. RESULTS: Using this screen, we have identified CD155 (the poliovirus receptor) as a mediator of tumor cell invasion through its role in migration. Knockdown of CD155 by FALI or by RNAi resulted in a significant decrease in transwell migration of HT1080 fibrosarcoma cells towards a serum chemoattractant. CD155 was found to be highly expressed in multiple cancer cell lines and primary tumors including glioblastoma (GBM). Knockdown of CD155 also decreased migration of U87MG GBM cells. CD155 is recruited to the leading edge of migrating cells where it colocalizes with actin and αv-integrin, known mediators of motility and adhesion. Knockdown of CD155 also altered cellular morphology, resulting in cells that were larger and more elongated than controls when plated on a Matrigel substrate. CONCLUSION: These results implicate a role for CD155 in mediating tumor cell invasion and migration and suggest that CD155 may contribute to tumorigenesis

Role of plants in anticancer drug discovery

Cancer is one of the major causes of death and the number of new cases, as well as the number of individuals living with cancer, is expanding continuously. Worldwide the alarming rise in mortality rate due to cancer has fuelled the pursuit for effective anticancer agents to combat this disease. Finding novel and efficient compounds of natural origin has been a major point of concern for research in the pharmaceutical sciences. Plants have been seen to possess the potential to be excellent lead structures and to serve as a basis of promising therapeutic agents for cancer treatment. Many successful anti-cancer drugs currently in use or their analogues are plant derived and many more are under clinical trials. This review aims to highlight the invaluable role that plants have played, and continue to play, in the discovery of anticancer agents.We acknowledge the University of Pretoria for Postdoctoral fellowship to J.K. and B.A.M.http://www.elsevier.com/locate/phytolhb2017ChemistryGenetic

Babbel Language Learning Podcasts

Winner of the 2020 IELA E-Learning Award in the category Mobile Learning, Babbel’s slate of language learning podcasts provide innovative audio learning experiences, designed and hosted by linguistic experts. This article describes the pedagogical method and expertise behind Babbel's podcasts along with some best practices for creating effective audio-based learning experiences