On-chip recalcification of citrated whole blood using a microfluidic herringbone mixer

In vitro assays of platelet function and coagulation are typically performed in the presence of an anticoagulant. The divalent cation chelator sodium citrate is among the most common because its effect on coagulation is reversible upon reintroduction of divalent cations. Adding divalent cations into citrated blood by batch mixing leads to platelet activation and initiation of coagulation after several minutes, thus limiting the time blood can be used before spontaneously clotting. In this work, we describe a herringbone microfluidic mixer to continuously introduce divalent cations into citrated blood. The mixing ratio, defined as the ratio of the volumetric flow rates of citrated blood and recalcification buffer, can be adjusted by changing the relative inlet pressures of these two solutions. This feature is useful in whole blood assays in order to account for differences in hematocrit, and thus viscosity. The recalcification process in the herringbone mixer does not activate platelets. The advantage of this continuous mixing approach is demonstrated in microfluidic vascular injury model in which platelets and fibrin accumulate on a collagen-tissue factor surface under flow. Continuous recalcification with the herringbone mixer allowed for flow assay times of up to 30 min, more than three times longer than the time achieved by batch recalcification. This continuous mixer allows for measurements of thrombus formation, remodeling, and fibrinolysis in vitro over time scales that are relevant to these physiological processes.     

Learning science through talking science in elementary classroom

Elementary students in grade two make sense of science ideas and knowledge through their contextual experiences. Mattis Lundin and Britt Jakobson find in their research that early grade students have sophisticated understandings of human anatomy and physiology. In order to understand what students’ know about human body and various systems, both drawings and spoken responses provide rich evidence of their understanding of the connections between science drawings and verbal explanations. In this forum contribution, we present several theoretical connections between everyday language and science communication and argue that building communication skills in science are essential. We also discuss how young participants should be valued and supported in research. Finally we discuss the need for multimodal research methods when the research participants are young.     

Predictive validity of a three-dimensional model of performance anxiety in the context of tae-kwon-do

We tested the predictive validity of the recently validated three-dimensional model of performance anxiety (Chang, Hardy, & Markland, 2009) with elite tae-kwon-do competitors (N = 99). This conceptual framework emphasized the adaptive potential of anxiety by including a regulatory dimension (reflected by perceived control) along with the intensity-oriented dimensions of cognitive and physiological anxiety. Anxiety was assessed 30 min before a competitive contest using the Three-Factor Anxiety Inventory. Competitors rated their performance on a tae-kwon-do-specific performance scale within 30 min after completion of their contest. Moderated hierarchical regression analyses revealed initial support for the predictive validity of the three-dimensional performance anxiety model. The regulatory dimension of anxiety (perceived control) revealed significant main and interactive effects on performance. This dimension appeared to be adaptive, as performance was better under high than low perceived control, and best vs. worst performance was associated with highest vs. lowest perceived control, respectively. Results are discussed in terms of the importance of the regulatory dimension of anxiety.     

Cultural Frame Switching and Emotion Among Mexican Americans

Recent evidence indicates that bicultural individuals shift between interpretive frames rooted in different cultures in response to cues encountered in a given situation. The explanation for these shifts has been labeled cultural frame switching. The current research sought to investigate the effect of priming culture among Mexican Americans. Culture was primed by exposing either Mexican or American icons to Mexican Americans prior to the individuals completing an attribution task followed by completing questionnaires assessing emotion. Results revealed that participants primed with American icons reported fewer external attributions and less positive emotion than did participants primed with Mexican icons.     

The impact of professional learning on in-service teachers’ pedagogical delivery of literacy-infused science with middle school English learners: a randomised controlled trial study in the U.S

ABSTRACT

Research in the United States show that professional learning (PL) can improve classroom instruction. However, teachers, especially educators in the content areas, receive insufficient training specific to meeting the language and academic needs of English learners (ELs). The purpose of the current randomized controlled trial (RCT) study was to introduce a high-quality PL program for supporting middle school teachers in teaching science to ELs through classroom observations, so as to evaluate whether in-service science teachers’ instructional delivery can be shaped by intensive, structured, and ongoing PL. Results indicated that after receiving PL, treatment teachers allocated a significantly higher portion of their instructional time in teaching content language, developing students’ expressive language skills, small group and pair activities, implementing strategies evidenced to effective with ELs, and providing more opportunities for students to participate in hands-on activities that were content-related and grade-appropriate. Practical implications for PL were discussed for an international audience.     

Revisiting print exposure: exploring differential links to vocabulary,comprehension and reading rate

Undergraduates (N=171) completed a revised version of the Author Recognition Test ( Stanovich & West, 1989 ). The resulting print exposure scores were divided into two dimensions: personal reading experience (primary print knowledge – PPK) and secondary print knowledge (SPK). Both PPK and SPK were correlated with print exposure, but not with each other. PPK correlated more strongly with reading‐related variables (vocabulary, comprehension and reading rate) than did SPK. Of particular importance, PPK accounted for variance in all three criterion variables after the effects of SPK had been factored out. Thus, these data support the notion that it is the act of reading over and above memory for reading‐related information that furthers the development of linguistic skill.