Density-dependent separation of encapsulated cells in a microfluidic channel by using a standing surface acoustic wave

This study presents a method for density-based separation of monodisperse encapsulated cells using a standing surface acoustic wave (SSAW) in a microchannel. Even though monodisperse polymer beads can be generated by the state-of-the-art technology in microfluidics, the quantity of encapsulated cells cannot be controlled precisely. In the present study, mono-disperse alginate beads in a laminar flow can be separated based on their density using acoustophoresis. A mixture of beads of equal sizes but dissimilar densities was hydrodynamically focused at the entrance and then actively driven toward the sidewalls by a SSAW. The lateral displacement of a bead is proportional to the density of the bead, i.e., the number of encapsulated cells in an alginate bead. Under optimized conditions, the recovery rate of a target bead group (large-cell-quantity alginate beads) reached up to 97% at a rate of 2300 beads per minute. A cell viability test also confirmed that the encapsulated cells were hardly damaged by the acoustic force. Moreover, cell-encapsulating beads that were cultured for 1 day were separated in a similar manner. In conclusion, this study demonstrated that a SSAW can successfully separate monodisperse particles by their density. With the present technique for separating cell-encapsulating beads, the current cell engineering technology can be significantly advanced.     

Polyester μ-assay chip for stem cell studies

The application of microfluidic technologies to stem cell research is of great interest to biologists and bioengineers. This is chiefly due to the intricate ability to control the cellular environment, the reduction of reagent volume, experimentation time and cost, and the high-throughput screening capabilities of microscale devices. Despite this importance, a simple-to-use microfluidic platform for studying the effects of growth factors on stem cell differentiation has not yet emerged. With this consideration, we have designed and characterized a microfluidic device that is easy to fabricate and operate, yet contains several functional elements. Our device is a simple polyester-based microfluidic chip capable of simultaneously screening multiple independent stem cell culture conditions. Generated by laser ablation and stacking of multiple layers of polyester film, this device integrates a 10 × 10 microwell array for cell culture with a continuous perfusion system and a non-linear concentration gradient generator. We performed numerical calculations to predict the gradient formation and calculate the shear stress acting on the cells inside the device. The device operation was validated by culturing murine embryonic stem cells inside the microwells for 5 days. Furthermore, we showed the ability to maintain the pluripotency of stem cell aggregates in response to concentrations of leukemia inhibitory factor ranging from 0 to ∼1000 U/ml. Given its simplicity, fast manufacturing method, scalability, and the cell-compatible nature of the device, it may be a useful platform for long-term stem cell culture and studies.     

Knowledge complementarity and knowledge exchange in supply channel relationships

Existing literature on knowledge exchange in inter-organizational relationships (e.g., a supply channel) reveals two opposing forces at work: (1) collaborative behavior and (2) opportunistic behavior. A concurrent assessment of the opposing perspectives and the contingencies under which each is relevant for supply channel performance can add valuable insights about the dynamics of knowledge exchange. We juxtapose the two behavior patterns using social capital theory and transaction cost economics (TCE) respectively as the explicators and employ knowledge complementarity as the contingency to reconcile the opposing behavior patterns. The choice of knowledge complementarity in this role stems from ample theoretical and empirical support in prior literature about the criticality of this factor in inter-firm knowledge exchange.     

Screening for harsh punishment in a pediatric primary care clinic

ObjectivesTo determine: (1) the prevalence of harsh punishment among parents in a pediatric clinic, and (2) the sensitivity, specificity, predictive values, and stability of a brief screening measure.MethodsA subset of families involved in a study of child maltreatment prevention were recruited for this study. Two items in a parent screening questionnaire (PSQ) were related to child punishment. Comparisons were made between parents’ responses on the PSQ and on the Parent-Child Conflict Tactic Scale (CTSPC).ResultsOn the PSQ, 7% of parents of infants and 32% of parents of toddlers/preschoolers reported that their child was difficult to take care of or needed to be hit or spanked. On the CTSPC, 14% of the infants had experienced physical assault and 21% psychological aggression. For older children, subscales were modified to exclude common discipline measures, resulting in 20% experiencing physical assault and 19% psychological aggression. Sensitivities for the PSQ were relatively poor for infants, but moderate for older children. Specificities were good. Stability was adequate.ConclusionsHarsh punishment experienced by older children was similar to that in published studies. Punishment of infants is concerning. The PSQ can be used to screen out parents who are not using harsh discipline measures.Practice implicationsThe PSQ has variable utility in determining which families are using harsh punishment. Until the measure can be further refined, universal counseling is needed.     

The impact of an elaborated assessee’s role in peer assessment

The purpose of this study was to investigate the effects of an elaborated assessee’s role on metacognitive awareness, performance and attitude in peer assessment. Two intact groups (a total of 82 students) were randomly assigned to a treatment condition (having back‐feedback activity) or a control condition (not having back‐feedback activity). The results indicated that, regarding metacognitive awareness, when participants played the elaborated assessee role, they tended to report higher metacognitive awareness in their learning process. Regarding performance, when participants played the elaborated assessee role, they tended to receive better scores in making a concept map. Regarding attitude, when participants played the elaborated assessee role, they reported greater motivation towards the peer assessment. The findings of this study suggest instructional implications for those who want to employ peer assessment as a learning method by showing the effectiveness of a well‐developed role design, specifically one that includes the back‐feedback activity.     

Situational interest,cognitive engagement,and achievement in physical education

Students’ learning has been the center of schooling. This study examined the contribution of situational interest motivation and cognitive engagement in workbooks to student achievement in learning health-related fitness knowledge. Situational interest, performance on solving workbook problems, and knowledge gain in cardio-respiratory fitness and benefits were measured in 670 third-grade students from 13 randomly selected urban elementary schools. Structural equation modeling and regression curve estimation analyses revealed that situational interest contributed little to workbook performance and knowledge gain. Performance on solving workbook problems contributed significantly to knowledge gain. The results also show that skipping workbook tasks had stronger negative impact on knowledge gain than performing the tasks incorrectly, suggesting the importance of engaging students in the learning process by attempting the workbook tasks. The findings reinforced the value of using workbooks to facilitate cognitive knowledge learning in physical education, but raised questions about the direct function of situational interest on engaging students in cognitive learning.     

Is combining child labour and school education the right approach? Investigating the Cambodian case

The paper considers whether letting children combine work and school is a valid and effective approach in Cambodia. Policy makers’ suggestions that child labour should be allowed to some extent due to household poverty appear ungrounded as no significant relation between children's work and household poverty is found while arranging school timetables flexibly in order to accommodate households’ perceived need for children's labour may increase problems of insufficient teaching hours if schools conduct their timetables unreliably. Considering these issues, the paper suggests the need for a more diversified approach to dealing with the impact of child labour on their school education.     

From Evidence to Action: A Seamless Process in Formative Assessment?

Based on the results of a generalizability study of measures of teacher knowledge for teaching mathematics developed at the National Center for Research on Evaluation, Standards, and Student Testing at the University of California, Los Angeles, this article provides evidence that teachers are better at drawing reasonable inferences about student levels of understanding from assessment information than they are at deciding the next instructional steps. We discuss the implications of the results for effective formative assessment and end with considerations of how teachers can be supported to know what to teach next.     

Crosslinguistic influence on phonological awareness for Korean–English bilingual children

This study examined (1) the potential influence of oral language characteristics of two languages that bilingual children acquire on their PA and (2) the relationship of PA in L1 with PA and literacy skills in L2, using data from Korean–English bilingual children. Thirty three Korean–English bilingual children, composed of two subsamples from two different locations/bilingual programs, participated in the study. The findings showed that the sample of bilingual children from two bilingual programs differed in their mean performances on intrasyllabic phonological awareness in Korean (i.e., rime awareness and body awareness). Furthermore, children’s Korean rime awareness, but not body awareness, was positively related to their phonological awareness and literacy skills in English. Finally, these children’s phonological awareness in Korean made a positive contribution to English decoding skills even after controlling for their English sight word reading skills. The results are discussed in light of interlingual influence on bilingual children’s phonological awareness.

Training needs and online learning preferences of early childhood professionals

Providing early childhood professionals with professional development opportunities to enhance their skills and knowledge can improve quality of care. For professional development to be valued by the early childhood workforce, it is essential to offer meaningful content that accommodates the needs of the learner. With an increasing demand for quality professional development, as well as the expansion of online learning opportunities, this qualitative study explores the opinions of 14 North Carolina early childhood professionals regarding their professional development training needs and online learning preferences. Training content needs, experiences with online learning, and recommendations for training development are discussed. This study has implications for professional development creators and trainers for advancing the education and growth of the early childhood workforce.