J. Neurochem. (2010) 112, 1431–1441.
Abstract
As embryonic stem cell‐derived neural progenitors (NPs) have the potential to be used in cell replacement therapy, an understanding of the signaling mechanisms that regulate their terminal differentiation is imperative. In previous studies, we discovered the presence of functional μ opioid receptors (MOR) and κ opioid receptors (KOR) in mouse embryonic stem cells and NPs. Here, MOR and KOR immunoreactivity was detected in NP‐derived oligodendrocytes during three stages of their maturation in vitro. Moreover, we examined the modulation of retinoic acid‐induced NP differentiation to astrocytes and neurons by μ, [D‐ala2, mephe4, gly‐ol5] enkephalin, or κ, U69, 593, opioids. Both opioid agonists inhibited NP‐derived neurogenesis and astrogenesis via their corresponding receptors as determined by immunocytochemistry. By administering selective inhibitors, we found that opioid inhibition of NP‐derived astrogenesis was driven via extracellular‐signal regulated kinase (ERK), while the p38 mitogen‐activated protein kinase pathway was implicated in opioid attenuation of neurogenesis. In addition, μ and κ opioids stimulated oligodendrogenesis from NP‐derived NG2+ oligodendrocyte progenitors via both ERK and p38 signaling pathways. Accordingly, both opioids induced ERK phosphorylation in NG2+ cells. These results indicate that small molecules, such as MOR and KOR agonists may play a modulatory role in NP terminal differentiation.
Context information plays an important role in context-aware mobile commerce (m-commerce) applications. Context information must be preprocessed, integrated and modelled before being stored and then used in a context-aware m-commerce application. Based on Knowledge Management (KM) theories and practice, this paper proposes a framework that uses several information technologies to collect, process, integrate, model, store and use context information. This framework will help effectively manage this information, as well as provide integrated context information about location, weather, time and user activities to enable context-awareness of an m-commerce application.
In the midst of the global outbreak with over 300,000 worldwide death cases of COVID-19, Canada has reported 79,101 confirmed cases of the novel coronavirus (COVID-19) as of May 19, 2020, in which the severity differs from region to region. To provide a timely view and understanding of the evolving pandemic in Canada, we develop a real time interactive web-based platform which primarily includes data visualization and statistical analysis. The website highlights real time tracking of the development of COVID-19 with visualized graphs and forecasts future trends with applications of different statistical predictive models. By providing research-based statistical analysis, we are able to shed the light on the epidemiological characteristics of COVID-19. We also provide timely social news and preventive measures from the government on the website.
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