Collagen-based brain microvasculature model in vitro using three-dimensional printed template

We present an engineered three-dimensional (3D) in vitro brain microvasculature system embedded within the bulk of a collagen matrix. To create a hydrogel template for the functional brain microvascular structure, we fabricated an array of microchannels made of collagen I using microneedles and a 3D printed frame. By culturing mouse brain endothelial cells (bEnd.3) on the luminal surface of cylindrical collagen microchannels, we reconstructed an array of brain microvasculature in vitro with circular cross-sections. We characterized the barrier function of our brain microvasculature by measuring transendothelial permeability of 40 kDa fluorescein isothiocyanate-dextran (Stoke''s radius of ∼4.5 nm), based on an analytical model. The transendothelial permeability decreased significantly over 3 weeks of culture. We also present the disruption of the barrier function with a hyperosmotic mannitol as well as a subsequent recovery over 4 days. Our brain microvasculature model in vitro, consisting of system-in-hydrogel combined with the widely emerging 3D printing technique, can serve as a useful tool not only for fundamental studies associated with blood-brain barrier in physiological and pathological settings but also for pharmaceutical applications.     

Moderate Association of Anthropometry,But Not Training Volume,With Race Performance in Male Ultraendurance Cyclists

In 28 male Caucasian nonprofessional ultracyclists, we investigated whether anthropometry or training volume had an influence on race speed in the 600 km at the Swiss Cycling Marathon 2007. Anthropometric parameters (age, body mass, body height, skin-fold thicknesses) were determined before the race to calculate body mass index and percent body fat. In addition, participants, using a training diary, recorded their training volume in hours and kilometers in the 3 months before the race. The influence of anthropometry and training volume on speed in the race as the dependent variable was investigated in a multiple linear regression model. Anthropometry showed a moderate association with speed in the race (r² = .178, p < .05), whereas training volume showed no association (r² = .000, p > .05). We concluded that anthropometry had a greater influence on race performance than training volume in recreational ultraendurance cyclists.     

Cuba’s Challenges Hosting the 1991 Pan-American Games and the Spectacle of the Revolution’s ‘Soft Power’

Abstract

This paper examines the confluence of global, regional, and national politics in the lead up to the 1991 Pan-American Games hosted by Cuba. Cuba’s contentious selection as host was wholly underpinned by the international politics of the time. Once selected, the preparations for the Games in Havana were surrounded by an unprecedented domestic economic crisis fueled by shifts in global politics. This paper analyzes how international politics informed the hosting of the 1991 Pan-American Games, and shaped the political challenge the Cuban government faced in hosting such an event. The Revolution’s use of sport domestically and internationally came to the forefront in its efforts as host and the results of those efforts proved to be providential given the emerging political economic contexts during and in the ensuing years after the Games.     

Girls Helping Girls: Assessing the Influence of College Student Mentors in an Afterschool Engineering Program

Current data suggest fewer females than males continue to be interested in engineering and that this gender gap is first evidenced during middle school years. One might expect that female engineering role models would encourage adolescent girls to pursue future careers in engineering and thereby increase the girls’ interests in and attitudes towards science and mathematics. This study sought to correlate middle school girls’ overall confidence in science and mathematics with a year-long, afterschool mentoring program led by female engineering students from a local university. The results demonstrated that there was a significant correlation between the quality of the mentoring relationship and the girls’ confidence in mathematics. The relationship between female role models and young girls’ attitudes toward science and mathematics is discussed.     

Categorical color coding by pigeons

Pigeons were trained on two independent tasks. One involved red and yellow hues, the other involved blue and green hues. For half of the birds, the two tasks were the same (i.e., both tasks were either matching-to-sample, or oddity-from-sample). For the remaining birds, the two tasks were different (i.e., one task was matching-to-sample; the other task was oddity-from-sample). Following acquisition, the pigeons were exposed to test trials on which either the correct or the incorrect comparison hue was replaced with one of the hues from the other task. On yellow-sample trials and on green-sample trials, the pigeons performed as if they had a common code for yellow and green. When there was one comparison available that was appropriate to the “yellow/green” code, performance remained high; but when either both comparisons or neither comparison was appropriate to the “yellow/green” code, performance dropped. The pigeons also tended to code red samples as green and to code blue samples as yellow. The results indicate that pigeons can categorically code colors under conditions that rule out a failure to discriminate among the colors.     

What we are really doing with ICT in physical education: a national audit of equipment, use, teacher attitudes, support, and training

This paper reports on the results from a detailed national audit of information communication technology (ICT) in physical education (PE), examining attitudes, training, numbers of pieces of equipment and hardware owned, and its employment and use across nine Local Education Authorities, six types of schools, and four types of Specialist College. After setting the context, a summary of the survey methods used and an overview of the findings from 500 schools are presented. Results from 252 questionnaires returned suggested that the majority of PE teachers felt that ICT was a valuable teaching tool; however, parity of training and ownership of equipment were not standard across the range of schools or regions. Furthermore, the data suggest a growing trend in ICT use in PE across England.     

Experimental and numerical investigation of buckling in rectangular steel plates with groove-shaped cutouts

Steel plates are widely used in various structures, such as the deck and bodies of ships and bridges, and in the aerospace industry. In many instances, these plates are subjected to axial compression loads that predispose the sheets to instability and buckling. In this study, we investigate the buckling and post-buckling behaviors of steel plates having groove-shaped cutouts of various dimensions and angles using finite element method (FEM) (by ABAQUS software) and experimental tests (by an Instron servohydraulic machine). Boundary conditions were clamped by supports at upper and lower ends and free supports at the other edges. The results of both numerical and experimental analyses are compared, which show a very good agreement between them. Finally, based on the experimental findings, formulas are presented for the determination of the buckling load of such plates.     

Myth and Reality: A review of empirical studies on giftedness

In this review all empirically based articles published in the years 1997 and 1998 in five acclaimed journals in the field of research of high ability and talent will be compared. For this purpose several questions will be taken into consideration, including the problems of the identification procedures used, the predominating research questions and the quality of the methodological standards. The results show that it is difficult to compare the studies due to the various procedures used to identify giftedness. In contrast, regarding the thematic orientation of the research studies themselves, the existence of a virulent problem in gifted research could be confirmed. The methodological standards adhered to in the studies give rise to troubling thoughts, possibly the most worrisome outcome being that the integration of a control group occurred in less than one-quarter of the studies. A definitive result of the study is the confirmation that gifted research is conducted within the framework of a fragmented research community where studies are performed under various methodological viewpoints, which are often unsatisfactory. The appearance of approximately one new publication per day is accompanied by the dangers of a metamorphosis of quality into pure quantity and the loss of any sort of conceptual overview. The aim of this article is, therefore, to determine whether these suspicions can be substantiated specifically regarding theoretical and methodological aspects of empirical studies in giftedness research.