Using laser Doppler vibrometry to measure capillary surface waves on fluid-fluid interfaces     

James Friend  Leslie Yeo 《Biomicrofluidics》2010,4(2)

Capillary wave phenomena are challenging to study, especially for microfluidics where the wavelengths are short, the frequencies are high, and the frequency distribution is rarely confined to a narrow range, let alone a single frequency. Those that have been studying Faraday capillary waves generated by vertical oscillation have chosen to work at larger scales and at low frequencies as a solution to this problem, trading simplicity in measurement for issues with gravity, boundary conditions, and the fidelity of the subharmonic capillary wave motion. Laser Doppler vibrometry using a Mach–Zehnder interferometer is an attractive alternative: The interface’s motion can be characterized at frequencies up to 40 MHz and displacements of as little as a few tens of picometers.  相似文献   

Referee acknowledgment for 2014     

Hsueh-Chia Chang  Leslie Y. Yeo 《Biomicrofluidics》2015,9(1)

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Disgust,Need for Affect,and Responses to Microbiome Research     

Ye Sun  Sara K. Yeo  Meaghan McKasy  Erika Shugart 《Mass Communication and Society》2019,22(4):508-534

Contributing to the literature on affective processing and attitude formation, this study investigates the effects of a discrete emotion (disgust) and an emotional disposition (need for affect [NFA]) on support for regulation in the context of microbiome research. Data from a web-based experiment (N = 1,005) showed that experienced disgust mediated the effect of disgust-eliciting information on support for regulation. This mediated relationship was moderated by NFA. More specifically, NFA moderated the path between experienced disgust and regulatory attitudes but not that between message exposure and experienced disgust. The two dimensions of NFA played different moderating roles: Emotional approach amplified the relationship between disgust and the attitudinal outcome, whereas emotional avoidance attenuated it. The study furthers understanding about how NFA influences emotional processing and contributes to research on disgust as a relatively understudied discrete emotion.  相似文献   

Professional noticing of coordinated mathematical thinking     

Tye G. Campbell  Sheunghyun Yeo 《British Educational Research Journal》2022,48(3):488-503

Over the past three decades, research and policy in many geographic regions has promoted a shift from direct, lecture-oriented mathematics instruction to inquiry-based, dialogic forms of instruction. While theory and research support dialogic instructional approaches, some have noted that the complexities of dialogic teaching make it difficult for teachers to implement. One mechanism by which teachers can improve their decision-making practices in dialogic classrooms is learning to notice (i.e. becoming aware of learners’ processes). While research has contributed frameworks for understanding how teachers notice individual learners’ mathematical thinking, there is little conceptualization regarding how teachers notice group processes in mathematics classrooms, which is integral to dialogic instruction. We offer a noticing framework termed professional noticing of coordinated mathematical thinking that describes how teachers notice group activity in mathematics classrooms. Professional noticing of coordinated mathematical thinking is conceptualized as a bi-dimensional process: noticing groups’ mathematical activity and noticing groups’ coordinated activity. Teachers must become aware of how groups approach the mathematical and collaborative nature of a task, since both of these aspects inform whether learners develop opportunities to learn in groups. The framework describes noticing practices integral to dialogic instruction and promotes inquiry for future research related to teaching moves in dialogic classrooms.  相似文献   

Impact of gender and prior knowledge on learning performance and motivation in a digital game-based learning biology course     

Yeo  Jun-Hui  Cho  I.-Hsuan  Hwang  Gwo-Haur  Yang  Hsi-Hsun 《Educational technology research and development : ETR & D》2022,70(3):989-1008

Educational technology research and development - Gender and prior knowledge may affect students' performance and motivation when simulations and games are used for learning. Accommodations...  相似文献   

The Home Literacy Environment and Preschool Children's Reading Skills and Interest     

Lay See Yeo  Winston W. Ong  Charis M. Ng 《Early education and development》2014,25(6):791-814

Research Findings: This study explored the association between the home literacy environment (HLE), conceptualized as comprising parents’ reading beliefs and home literacy practices, and preschoolers’ reading skills and reading interest. It also identified factors in the HLE that predict emerging reading competence and motivation to read. A total of 193 children age 6 years from 14 preschools across Singapore and their parents participated in the study. The parents completed a reading belief inventory, a family literacy activity inventory, and a demographic questionnaire that surveyed the child's reading interest. The children were administered a battery of standardized literacy tests. The study found a moderate relationship between the HLE and children's reading competencies and a strong relationship between the HLE and children's reading interest. When parents’ education level and children's age were controlled, hierarchical multiple regression analyses found that family literacy activities contributed more unique variance to children's reading outcomes and reading interest than did parents’ reading beliefs. Active parental involvement was the strongest component of the HLE, with parent–child engagement in reading and writing emerging as the best predictor of both the child's emerging reading skills and reading interest. With respect to reading beliefs, parents’ efficacy in supporting literacy development before their child attended school positively predicted reading competence, as did parents’ affect and verbal participation in fostering reading interest. However, verbal participation negatively predicted Singapore children's reading competence. Practice or Policy: The implications of the results were discussed.  相似文献   

Author's response     

Richard Yeo 《Metascience》2002,11(2):171-176

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Teachers’ experience with inclusive education in Singapore     

Lay See Yeo  Wan Har Chong  Maureen F. Neihart  Vivien S. Huan 《Asia Pacific Journal of Education》2016,36(1):69-83

Teachers’ positive attitude is most critically and consistently associated with successful inclusion. However, little is known about teachers’ first-hand encounters with inclusive education in Singapore. We present findings from a qualitative study on inclusion based on focus group interviews with 202 teachers from 41 resourced primary schools. The data were transcribed and coded using Interpretive Phenomenological Analysis and NVIVO software. Two broad clusters identified were teachers’ positive and negative experiences in implementing inclusion. More reference was made to negative than positive experiences. The most dominant negative experience was stress from challenging behaviours and instructional difficulties of catering adequately for diverse needs in the same classroom. The most salient positive experience was satisfaction with pupils’ progress and new learning for teachers. Classroom practices that facilitated inclusion and the value of training in shaping teachers’ attitudes towards inclusion were highlighted.  相似文献   

Ultrafast microfluidics using surface acoustic waves   总被引：2，自引：0，他引：2  

Leslie Y. Yeo  James R. Friend 《Biomicrofluidics》2009,3(1)

We demonstrate that surface acoustic waves (SAWs), nanometer amplitude Rayleigh waves driven at megahertz order frequencies propagating on the surface of a piezoelectric substrate, offer a powerful method for driving a host of extremely fast microfluidic actuation and micro∕bioparticle manipulation schemes. We show that sessile drops can be translated rapidly on planar substrates or fluid can be pumped through microchannels at 1–10 cm∕s velocities, which are typically one to two orders quicker than that afforded by current microfluidic technologies. Through symmetry-breaking, azimuthal recirculation can be induced within the drop to drive strong inertial microcentrifugation for micromixing and particle concentration or separation. Similar micromixing strategies can be induced in the same microchannel in which fluid is pumped with the SAW by merely changing the SAW frequency to rapidly switch the uniform through-flow into a chaotic oscillatory flow by exploiting superpositioning of the irradiated sound waves from the sidewalls of the microchannel. If the flow is sufficiently quiescent, the nodes of the transverse standing wave that arises across the microchannel also allow for particle aggregation, and hence, sorting on nodal lines. In addition, the SAW also facilitates other microfluidic capabilities. For example, capillary waves excited at the free surface of a sessile drop by the SAW underneath it can be exploited for micro∕nanoparticle collection and sorting at nodal points or lines at low powers. At higher powers, the large accelerations off the substrate surface as the SAW propagates across drives rapid destabilization of the drop free surface giving rise to inertial liquid jets that persist over 1–2 cm in length or atomization of the entire drop to produce 1–10 μm monodispersed aerosol droplets, which can be exploited for ink-jet printing, mass spectrometry interfacing, or pulmonary drug delivery. The atomization of polymer∕protein solutions can also be used for the rapid synthesis of 150–200 nm polymer∕protein particles or biodegradable polymeric shells in which proteins, peptides, and other therapeutic molecules are encapsulated within for controlled release drug delivery. The atomization of thin films behind a translating drop containing polymer solutions also gives rise to long-range spatial ordering of regular polymer spots whose size and spacing are dependent on the SAW frequency, thus offering a simple and powerful method for polymer patterning without requiring surface treatment or physical∕chemical templating.  相似文献   

Rapid production of protein-loaded biodegradable microparticles using surface acoustic waves     

Mar Alvarez  Leslie Y. Yeo  James R. Friend    Milan Jamriska 《Biomicrofluidics》2009,3(1)

We present a straightforward and rapid surface acoustic wave (SAW) atomization-based technique for encapsulating proteins into 10 μm order particles composed of a biodegradable polymeric excipient, using bovine serum albumin (BSA) as an exemplar. Scans obtained from confocal microscopy provide qualitative proof of encapsulation and show the fluorescent conjugated protein to be distributed in a relatively uniform manner within the polymer shell. An ELISA assay of the collected particles demonstrates that the BSA survives the atomization, particle formation, and collection process with a yield of approximately 55%. The SAW atomization universally gave particles with a textured morphology, and increasing the frequency and polymer concentration generally gave smaller particles (to 3 μm average) with reduced porosity.  相似文献