Recreating blood-brain barrier physiology and structure on chip: A novel neurovascular microfluidic bioreactor

The blood-brain barrier (BBB) is a critical structure that serves as the gatekeeper between the central nervous system and the rest of the body. It is the responsibility of the BBB to facilitate the entry of required nutrients into the brain and to exclude potentially harmful compounds; however, this complex structure has remained difficult to model faithfully in vitro. Accurate in vitro models are necessary for understanding how the BBB forms and functions, as well as for evaluating drug and toxin penetration across the barrier. Many previous models have failed to support all the cell types involved in the BBB formation and/or lacked the flow-created shear forces needed for mature tight junction formation. To address these issues and to help establish a more faithful in vitro model of the BBB, we have designed and fabricated a microfluidic device that is comprised of both a vascular chamber and a brain chamber separated by a porous membrane. This design allows for cell-to-cell communication between endothelial cells, astrocytes, and pericytes and independent perfusion of both compartments separated by the membrane. This NeuroVascular Unit (NVU) represents approximately one-millionth of the human brain, and hence, has sufficient cell mass to support a breadth of analytical measurements. The NVU has been validated with both fluorescein isothiocyanate (FITC)-dextran diffusion and transendothelial electrical resistance. The NVU has enabled in vitro modeling of the BBB using all human cell types and sampling effluent from both sides of the barrier.     

The Hit & Turn Tennis Test: an acoustically controlled endurance test for tennis players

This study was conducted to validate and evaluate the "Hit & Turn Tennis Test", an acoustically progressive on-court endurance test for tennis players. Ninety-eight competitive tennis players (53 males, 45 females) of different age groups participated in the study. For validation, the adult male players completed three Hit & Turn tests, one on a clay court and two on a carpet surface, a tennis-specific ball machine test and an incremental treadmill run in a randomized order. A stronger correlation between maximal performance (r = 0.81, P < 0.01) and maximal oxygen uptake (r = 0.96, P < 0.01) was observed between the Hit & Turn test and the ball machine test, than between the Hit & Turn test and the treadmill test. For test-retest, we found a significant correlation between maximal performance on the same (r = 0.83, P < 0.01) and on different surfaces (r = 0.74, P < 0.01). During test evaluation, maximal performance was higher in males than in females (P < 0.01) and increased by consecutive age group in boys (P < 0.01) but not in girls (P = 0.97). In conclusion, Hit & Turn maximum test performance can be recommended as a valid and reliable indicator for tennis-specific endurance.     

The Teaching Brain and the End of the Empty Vessel

I am excited to present this special section that explores the teaching brain. The goal of the series is to facilitate a transition in the lens on teaching from an empty vessel to a phenomenon as dynamic, variable, and context‐dependent as learning. This transformation will likely push all of us to reevaluate our understanding and research on teaching. Over the coming year, each issue will provide several articles that seek to shed light on a different aspect of this burgeoning new area of research. This issue opens the series with a piece designed to lay out the conceptual framework and evidence base for a new way to think about teaching: the teaching brain. Next, Michael Chazan gives an archeological grounding for the existence of teaching in the earliest ancestors of Homo sapiens. Sidney Strauss and Margalit Ziv then describe how teaching is a fundamental human cognitive ability. Together, these articles begin to create a paradigm shift in the definition of teaching. We look forward to an exciting journey.     

The role of visual representations for structuring classroom mathematical activity

It is our presupposition that there is still a need for more research about how classroom practices can exploit the use and power of visualization in mathematics education. The aim of this article is to contribute in this direction, investigating how visual representations can structure geometry activity in the classroom and discussing teaching practices that can facilitate students’ visualization of mathematical objects. We present one illustrative episode that shows how drawings of geometrical figures have a powerful role in structuring and modifying the mathematical activity in the classroom. It was selected from a database that we have been building to investigate the learning of mathematics in public elementary schools in Brazil. The framework of Activity Theory helped in the characterization of the episode as a system of interconnected activities. We discuss the changes and transformations perceived in those activities; and we explore the idea of miniature cycles of learning actions to focus on the mathematical learning that is taking place. We describe the dynamics and the complexity of the ongoing activity in the calculation of areas; and, how drawings form a part, and show their influence, in it. We argue that part of this influence was associated with the contradiction between abstract mathematical ideas and their empirical representations, revealed by the tensions perceived in the activities analysed; and, simultaneously, that we could see as an impelling force for the learning of the rules and norms which regulate the use of visual representations in school mathematics.     

The effects and characteristics of family involvement on a peer tutoring programme to improve the reading comprehension competence

The aim of the present study was to investigate the impact of an educational programme involving peer tutoring at school and family tutoring at home on child reading comprehension achievement in Catalunya, Spain. We drew upon a sample of 303 primary school students from 8 to 11 years old and 223 family tutors from home (61.5% mothers, 15% fathers, 17% both parents, 6.5% siblings). Reading comprehension performance was assessed through standardised tests in pre and post-test bases. Background variables were collected by means of student and parent questionnaires and also teacher and family interviews. An analysis of the family tutoring interactions was also performed. The main results showed positive effects for all the students, but especially for the 223 students who received family support. Overall, the study reveals the effectiveness of peer learning to improve reading comprehension skills and the potential of family involvement for the development of academic skills when the school provides trust and support for it.     

Homelessness in the elementary school classroom: social and emotional consequences

This study examined elementary school teachers’ experiences working with homeless students. Specifically, we focused on the psychosocial impacts of homelessness on students and their teachers. Qualitative, semi-structured interviews were conducted with 28 teachers who worked at designated public schools for family homeless shelters. A prominent theme that emerged from teachers’ accounts was how the instability tied to homelessness affected students’ behavioral, social, and emotional adjustment in the classroom (e.g. externalizing problems, difficulty developing peer relationships, and withdrawn behavior). Teachers’ own social and emotional competencies (e.g. fostering positive teacher–student relationships, and perspective taking) influenced the manner in which they responded to their students’ needs. Findings suggest that critical components may be lacking articulation in the McKinney-Vento Act’s Education for Homeless Children and Youth Program such as guidelines for teacher responsibilities, supports for teachers, and an emphasis not only on children’s academic but also social and emotional needs.     

Behind the By-Lines

Abstract

This article uses a critique of modernity to examine the perceived relationship between global citizenship education (GCE) and digital democracy (DD). We review critiques of citizenship education in the global imperative and of the relationship of technology to democratic engagement. An analogy expresses the problematic way that GCE and DD are both mutually compatible and complicit in ethical global justice issues. We end with a suggestion of a pedagogical framework through which educators can engage with an ethical approach to GCE and DD.     

Cytokine responses to resistance training in people with multiple sclerosis

Abstract

Exercise for individuals with multiple sclerosis (MS) has been shown to improve cardiovascular function, increase strength and endurance, and reduce fatigue. The impact of exercise on immune function in the disease, however, remains mostly unexplored. Ten female MS patients participated in an 8 week programme of twice-weekly progressive resistance training, with pre- and post-training assessment of serum concentrations of cytokines IL-2, IL-4, IL-6, IL-10, CRP, TNF-α and IFN-γ. After training, IL-4, IL-10, CRP and IFN-γ showed statistically reduced resting concentrations in blood, while TNF-α showed non-significant reductions and IL-2 and IL-6 remained unchanged. These results suggest that progressive resistance training may have an impact on cytokine concentrations in individuals with MS and should be confirmed in studies with stronger statistical power. The impact of these changes on overall immune function in MS and on disease status and prognosis remains to be determined.