A three dimensional thermoplastic microfluidic chip for robust cell capture and high resolution imaging

We present a low cost microfluidic chip integrating 3D micro-chambers for the capture and the analysis of cells. This device has a simple design and a small footprint. It allows the implementation of standard biological protocols in a chip format with low volume consumption. The manufacturing process relies on hot-embossing of cyclo olefin copolymer, allowing the development of a low cost and robust device. A 3D design of microchannels was used to induce high flow velocity contrasts in the device and provide a selective immobilization. In narrow distribution channels, the liquid velocity induces a shear stress that overcomes adhesion forces and prevents cell immobilization or clogging. In large 3D chambers, the liquid velocity drops down below the threshold for cell attachment. The devices can be operated in a large range of input pressures and can even be handled manually using simple syringe or micropipette. Even at high flow injection rates, the 3D structures protect the captured cell from shear stress. To validate the performances of our device, we implemented immuno-fluorescence labeling and Fluorescence in Situ Hybridization (FISH) analysis on cancer cell lines and on a patient pleural effusion sample. FISH is a Food and Drug Administration approved cancer diagnostic technique that provides quantitative information about gene and chromosome aberration at the single cell level. It is usually considered as a long and fastidious test in medical diagnosis. This process can be easily implanted in our platform, and high resolution fluorescence imaging can be performed with reduced time and computer intensiveness. These results demonstrate the potential of this chip as a low cost, robust, and versatile tool adapted to complex and demanding protocols for medical diagnosis.     

Early Training in Oral Comprehension and Phonological Skills: Results of a Three-Year Longitudinal Study

A sample of 1,273 4-year-old children were followed for 3 years. The children participated in 1 of 2 comprehension training programs, or in a phonological awareness training program. The comprehension programs explored the possibility of improving young children's oral comprehension in an educational setting. The first focused on the component skills of comprehension; the second involved storybook reading. Phonological awareness and oral language comprehension skills were measured repeatedly in the course of the study. The data were analyzed using multilevel growth-curve models. The results showed that it is possible to improve oral comprehension if the training focuses on its component skills and extends over 2 semesters. When these conditions were met, training effects still existed 9 months after the program had ended. Finally, phonological training improved phonological awareness but not comprehension, and comprehension-skill training improved oral comprehension but not phonological awareness.     

A latent profile analysis of teachers’ causal attribution for academic success or failure

European Journal of Psychology of Education - In educational contexts, interpersonal attributional theory (Weiner, 2019) posits that teachers’ beliefs about the causes underlying their...     

Technical variability of the Vivago® wrist-worn accelerometer

Abstract

The aim was to assess the technical variability of a new wrist-worn accelerometer under controlled conditions with a shaker device and during normal daily physical activities (PAs). In the first experiment, 10 wrist-worn accelerometers (Vivago^® Wellness, Paris, France) were attached to the shaker device. Variability was tested at five shaking frequencies (1.1, 2.1, 3.1, 4.1, and 10 Hz) for 10 min at each frequency. In the second experiment, 21 participants wore wrist-worn accelerometers and performed six consecutive 10-min periods of activity at increasing levels of intensity from sedentary to vigorous. Results from the first experiment show a modest inter- and intra-instrument reliability at low frequencies and that reliability improved as frequency increased. The inter-instrument coefficient of variation (CV) was 2.6–18.3%. The intra-instrument CV was 4.1–23.2%. Variability was similar in the second experiment with a CV inversely related to PA intensity. The inter- and intra-instrument CV varied from 24.2% and 19.9% for sedentary activities to 3.7% and 4.3% for vigorous PA, respectively. Results suggest that reliability was higher at high intensities, corresponding to moderate and vigorous PA, intensities generally recommended for public health purposes.     

Pharmacokinetic Models for Active Learning of Differential Equations

Abstract

We present adaptable activities for models of drug movement in the human body – pharmacokinetics – that motivate the learning of ordinary differential equations with an interdisciplinary topic. Specifically, we model aspirin, caffeine, and digoxin. We discuss the pedagogy of guiding students to understand, develop, and analyze models, progressing in complexity to a system of differential equations. We investigate the effects of parameter values that distinguish various health levels, and dosing that may have toxic effects. Our assignments include modeling in a student-centered, active, and increasingly inquiry-oriented setting through which the mathematics and biology inform and reinforce each other. We include supplemental information regarding inquiry methods, student learning outcomes, a student’s commentary about our activities, and support through mathematical communities such as POGIL and SIMIODE.     

The effects of player grip on the dynamic behaviour of a tennis racket

The aim of this article is to characterise the extent to which the dynamic behaviour of a tennis racket is dependent on its mechanical characteristics and the modulation of the player’s grip force. This problem is addressed through steps involving both experiment and modelling. The first step was a free boundary condition modal analysis on five commercial rackets. Operational modal analyses were carried out under “slight”, “medium” and “strong” grip force conditions. Modal frequencies and damping factors were then obtained using a high-resolution method. Results indicated that the dynamic behaviour of a racket is not only determined by its mechanical characteristics, but is also highly dependent on the player’s grip force. Depending on the grip force intensity, the first two bending modes and the first torsional mode frequencies respectively decreased and increased while damping factors increased. The second step considered the design of a phenomenological hand-gripped racket model. This model is fruitful in that it easily predicts the potential variations in a racket’s dynamic behaviour according to the player’s grip force. These results provide a new perspective on the player/racket interaction optimisation by revealing how grip force can drive racket dynamic behaviour, and hence underlining the necessity of taking the player into account in the racket design process.     

Bilingualism and phonological awareness: the case of bilingual (French–Occitan) children

The present study investigated the development of linguistic awareness in children exposed to the early learning of a second language in Grades 3–5 of primary school, i.e. between the ages of 8 and 10. The aim was to determine whether this bilingual experience enhanced the development of phonological awareness in beginning readers in a bilingual French-regional language school programme compared with a population of monolingual children receiving traditional education. More specifically, in light of research promoting the hypothesis of a “bilingual advantage”, we set out to determine exactly how long children need to be exposed to a second language before bilingualism starts to influence the development of their phonological awareness. Tasks designed to assess phonological awareness were administered to more than a hundred children. Results suggest that children who have undergone a bilingual school programme display a more highly developed phonological awareness than their monolingual peers from age 9 onwards, i.e. in Grade 4. These results are discussed in the light of ongoing research on bilingualism, bilingual education and threshold theory.     

Challenges in Characterizing the “Mommy Brain”

SYNOPSIS

Parental neuroimaging promises to shed light on how humans adapt to the demands of parenthood, but this research is not without challenges. A study in this issue reports differences between mothers’ and non-mothers’ default mode network activation during a goal-oriented task accompanied by human vocalizations. However, they did not find hypothesized differences in response specifically to infant cry, and the reach of conclusions that can be made based on these findings is limited. In my commentary, I present ideas for ways this work could be extended to make more definitive statements about the nature and potential benefits of parental brain adaptations.