Examination of the role of transient receptor potential vanilloid type 4 in endothelial responses to shear forces

Shear stress is the major mechanical force applied on vascular endothelial cells by blood flow, and is a crucial factor in normal vascular physiology and in the development of some vascular pathologies. The exact mechanisms of cellular mechano-transduction in mammalian cells and tissues have not yet been elucidated, but it is known that mechanically sensitive receptors and ion channels play a crucial role. This paper describes the use of a novel and efficient microfluidic device to study mechanically-sensitive receptors and ion channels in vitro, which has three independent channels from which recordings can be made and has a small surface area such that fewer cells are required than for conventional flow chambers. The contoured channels of the device enabled examination of a range of shear stresses in one field of view, which is not possible with parallel plate flow chambers and other previously used devices, where one level of flow-induced shear stress is produced per fixed flow-rate. We exposed bovine aortic endothelial cells to different levels of shear stress, and measured the resulting change in intracellular calcium levels ([Ca²⁺]_i) using the fluorescent calcium sensitive dye Fluo-4AM. Shear stress caused an elevation of [Ca²⁺]_i that was proportional to the level of shear experienced. The response was temperature dependant such that at lower temperatures more shear stress was required to elicit a given level of calcium signal and the magnitude of influx was reduced. We demonstrated that shear stress-induced elevations in [Ca²⁺]_i are largely due to calcium influx through the transient receptor potential vanilloid type 4 ion channel.     

Help-seeking tendencies during early adolescence: An examination of motivational correlates and consequences for achievement

The present study examined the motivational correlates and achievement consequences of students’ help-seeking tendencies during sixth grade (N = 217). Students’ grades were collected from school records at the beginning and end of the school year. Midway through the year students reported on their academic self-efficacy and social demonstration goals; teachers reported on students’ help-seeking tendencies. First quarter grades and academic self-efficacy were positively related to adaptive help seeking and negatively related to avoidant help seeking. In addition, a social demonstration-approach goal was negatively related to adaptive help seeking. Help-seeking tendencies predicted 3rd quarter grades, controlling for 1st quarter grades.     

Re-bordering spaces of trauma: auto-ethnographic reflections on the immigrant and refugee experience in an inner-city high school in Toronto

The objective of this research study is to offer a glimpse into the lives of some newly-arrived students of different racial, linguistic and religious backgrounds as they confront the process of immigration and therefore personal and social displacement within the context of a Toronto inner-city high school. These students carry with them hidden but enduring scars that influence all aspects of their educational lives. In many cases their experience is steeped in trauma. Using auto-ethnographic methodology, this research is devoted to giving voice to these students who inhabit a space filled with suffering and loss but also resilience and cautious hope. If we really care about these vulnerable students in our classrooms, we must rethink and reshape our understanding of teaching and learning that is more fundamentally linked to the lived experiences of students coming from places of war and other oppressions. These issues are crucial for the future of nation-building and citizenship education in pluralistic Western societies such as Canada, both in and out of school.     

Bromo-oxidation reaction in enzyme-entrapped alginate hollow microfibers

In this article, the authors present the fabrication of an enzyme-entrapped alginate hollow fiber using a microfluidic device. Further use of enzyme-entrapped alginate hollow fibers as a biocatalytic microchemical reactor for chemical synthesis is also deliberated in this article. To ensure that there is no enzyme leaching from the fiber, fiber surfaces were coated with chitosan. To confine the mobility of reactants and products within the porous hollow fibers the entire fibers were embedded into a transparent polydimethylsiloxane (PDMS) matrix which also works as a support matrix. A vanadium-containing bromoperoxidase enzyme isolated from Corallina confusa was used as a model enzyme to demonstrate the use of these alginate hollow-fiber reactors in bromo-oxidation of phenol red to bromophenol blue at different dye flow rates. Stability of the entrapped enzyme at different temperatures and the effect of the chitosan coating on the reaction conversion were also studied. It was observed that molecules as big as 27 kDa can be retained in the matrix after coating with chitosan while molecules with molecular-weight of around 378 Da can still diffuse in and out of the matrix. The kinetic conversion rate in this microfluidic bioreactor was more than 41-fold faster when compared with the standard test-tube procedure.     

Introducing e-portfolios to pre-service teachers as tools for reflection and growth: lessons learnt

E-portfolios are being introduced into initial teacher education programmes internationally to help pre-service teachers build records of their learning journeys and develop into reflective practitioners; to allow them to assemble collections of evidence of their achievements against graduate standards, which can function as digital CVs; and to facilitate the seeding of personal learning networks that will support lifelong learning after graduation. Despite certain tensions between these aims, the potential benefits of e-portfolios make them an increasingly popular choice in teacher education. In this article, we discuss the introduction of Wi-Fi-based e-portfolios into a Master of Teaching programme at an Australian university. These served primarily as developmental e-portfolios, or personal learning environments (PLEs), and were designed to place particular emphasis on reflective practice. We describe how the e-portfolios were perceived and used by pre-service teachers in the first year of their implementation, and indicate the challenges and limitations encountered. Lessons learnt from the implementation are outlined and recommendations are proposed.     

Statewide Initiative to Embed Consumer Health Librarians in Public Libraries: A Case Study

In 2004 a collaborative, statewide outreach project in Delaware was undertaken where consumer health librarians were embedded in public libraries. In order to explore the effect of the embedded librarians on the quality of health information provision, unobtrusive reference visits were made to half of the public libraries in the state. The query “Do vaccines cause autism?” was posed to library staff; resources provided were recorded. In 67 percent of visits, public library staff provided authoritative health information resources. It appears the embedded librarians had a positive residual effect on the provision of authoritative health resources for addressing an ambiguous query.     

User innovation and knowledge sourcing: The case of financial software

According to user innovation literature, users can create important innovations and the novel functionalities embedded in those user innovations often become the sources of subsequent innovations by both other users and manufacturers. However, manufacturers are often hesitant in commercializing an innovation created by a single user due to the uncertainty around the market demands. We propose that such hesitancy will decrease when an increasing number of other users source knowledge elements from the focal user innovation and reproduce the novel functionality. Once the focal user innovation is commercialized by manufacturers, other users can purchase the novel functionality from the market rather than reproducing it in house. We propose that users capable of drawing on innovation resources are more likely to maintain in-house reproduction of the focal user innovation than users low on innovation resources. By using the Vector Autoregressive (VAR) model and Impulse Response Function (IRF) analysis method, we analyze knowledge sourcing activities from financial software patents data, and the findings provide empirical supports for our propositions.     

Distributed fusion receding horizon filtering for uncertain linear stochastic systems with time-delay sensors

A new distributed fusion receding horizon filtering problem is investigated for uncertain linear stochastic systems with time-delay sensors. First, we construct a local receding horizon Kalman filter having time delays (LRHKFTDs) in both the system and measurement models. The key technique is the derivation of recursive error cross-covariance equations between LRHKFTDs in order to compute the optimal matrix fusion weights. It is the first time to present distributed fusion receding horizon filter for linear discrete-time systems with delayed sensors. It has a parallel structure that enables processing of multisensory time-delay measurements, so the calculation burden can be reduced and it is more reliable than the centralized version if some sensors turn faulty. Simulations for a multiple time-delays system show the effectiveness of the proposed filter in comparison with centralized receding horizon filter and non-receding versions.