Hand-powered microfluidics: A membrane pump with a patient-to-chip syringe interface     

Max M. Gong  Brendan D. MacDonald  Trung Vu Nguyen  David Sinton 《Biomicrofluidics》2012,6(4)

In this paper, we present an on-chip hand-powered membrane pump using a robust patient-to-chip syringe interface. This approach enables safe sample collection, sample containment, integrated sharps disposal, high sample volume capacity, and controlled downstream flow with no electrical power requirements. Sample is manually injected into the device via a syringe and needle. The membrane pump inflates upon injection and subsequently deflates, delivering fluid to downstream components in a controlled manner. The device is fabricated from poly(methyl methacrylate) (PMMA) and silicone, using CO₂ laser micromachining, with a total material cost of ∼0.20 USD/device. We experimentally demonstrate pump performance for both deionized (DI) water and undiluted, anticoagulated mouse whole blood, and characterize the behavior with reference to a resistor-capacitor electrical circuit analogy. Downstream output of the membrane pump is regulated, and scaled, by connecting multiple pumps in parallel. In contrast to existing on-chip pumping mechanisms that typically have low volume capacity (∼5 μL) and sample volume throughput (∼1–10 μl/min), the membrane pump offers high volume capacity (up to 240 μl) and sample volume throughput (up to 125 μl/min).  相似文献   

Re-imagining teachers’ identity and professionalism under the condition of international education     

Ly Thi Tran  Nhai Thi Nguyen 《Teachers and Teaching》2013,19(8):958-973

Around the world, 4.3 million students are engaged in international education each year. However, there is a paucity in theory and empirical research on teachers’ professionalism in international education. This paper aims to fill out this gap and contribute to our understanding of teachers’ changing roles and identity due to the impact of internationalisation and the growth of international students. Drawing on positioning theory as a conceptual framework to understand teachers’ roles and identity, this paper shows the emergence of teacher sub-identities as a reciprocal intercultural learner and an adaptive agent. It argues that these sub-identities are central to teachers’ development of cosmopolitan qualities in the contemporary context of international education.  相似文献   

A Case Study of Students’ Motivation in College Algebra Courses     

Giang-Nguyen T. Nguyen 《Community College Journal of Research & Practice》2013,37(8):693-707

This paper examines data from a larger study that focused upon students’ experiences and motivations in a college algebra course. The study revealed that students failed this course because of various factors and continued to view this course as a “gatekeeper” class. Through a stepwise multiple regression, the analysis of the ARCS instrument showed that Attention, Relevance, and Confidence were strong predictors of Satisfaction in the course.  相似文献   

Super-twisting observer-based sliding mode control with fuzzy variable gains and its applications to fully-actuated hexarotors     

Ngo Phong Nguyen  Wonhee Kim  Jun Moon 《Journal of The Franklin Institute》2019,356(8):4270-4303

In this paper, we consider the super-twisting observer-based sliding mode control algorithm with fuzzy variable gains (STOSMC) for the fully-actuated hexarotor. Our hexarotor has full actuation due to six titled propellers that allows to control position and orientation (attitude) simultaneously, and resolves the singularity problem of the rotational matrix by using the quaternion modeling framework. We show that the proposed STOSMC for the hexarotor guarantees finite-time convergence of the estimation error and asymptotic stability of the hexarotor. In simulations, we demonstrate the nonsingularity and fully-actuated control performance of the hexarotor by considering extreme position and attitude control scenarios. Moreover, the simulation results show that the hexarotor achieves the fast and precise tracking performance to the desired position and the desired attitude and the chattering phenomenon is reduced compared with the fixed-gains observer-based super-twisting sliding mode control due to the fuzzy mechanism.  相似文献   

Less than expected—The minor role of foreign firms in upgrading domestic suppliers—The case of Vietnam     

Thi Xuan Thu Nguyen  Javier Revilla Diez 《Research Policy》2019,48(6):1573-1585

Vietnam is an important case for studying the impact of foreign firms’ backward linkages on local firms’ productivity. As an emerging economy Vietnam became the second most popular FDI destination after China in Pacific Asia since 2014. Our empirical analysis for Vietnam as a whole demonstrates a significant difference in the productivity growth between domestic suppliers who have a direct linkage with foreign firms and non-suppliers. This is also true for the Southeast Region (SE) with Ho-Chi-Minh City as economic center. However, in the Red River Delta (RRD), that difference is not statistically significant. Based on in-depth interviews with domestic suppliers, we reveal that in the RRD, effects of foreign firms on the productivity upgrading of domestic suppliers are indirect and limited while internal factors like absorptive capacity are more important for the productivity growth. These regional differences can be traced back to different regional specializations which still persist from the pre-reform era.  相似文献   

Web document summarization by exploiting social context with matrix co-factorization     

Minh-Tien Nguyen  Viet Cuong Tran  Xuan Hoai Nguyen  Le-Minh Nguyen 《Information processing & management》2019,56(3):495-515

In the context of social media, users usually post relevant information corresponding to the contents of events mentioned in a Web document. This information posses two important values in that (i) it reflects the content of an event and (ii) it shares hidden topics with sentences in the main document. In this paper, we present a novel model to capture the nature of relationships between document sentences and post information (comments or tweets) in sharing hidden topics for summarization of Web documents by utilizing relevant post information. Unlike previous methods which are usually based on hand-crafted features, our approach ranks document sentences and user posts based on their importance to the topics. The sentence-user-post relation is formulated in a share topic matrix, which presents their mutual reinforcement support. Our proposed matrix co-factorization algorithm computes the score of each document sentence and user post and extracts the top ranked document sentences and comments (or tweets) as a summary. We apply the model to the task of summarization on three datasets in two languages, English and Vietnamese, of social context summarization and also on DUC 2004 (a standard corpus of the traditional summarization task). According to the experimental results, our model significantly outperforms the basic matrix factorization and achieves competitive ROUGE-scores with state-of-the-art methods.  相似文献   

Bidirectional longitudinal relationship between Chinese children's compounding awareness and vocabulary knowledge from Grades 3 to 6     

Ruibo Xie  Xinchun Wu  Thi Phuong Nguyen  Ying Zhao  Jie Feng 《Journal of Research in Reading》2020,43(4):482-495

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A Comparison of the Effects of Two Different Online Homework Systems on Levels of Knowledge Retention in General Chemistry Students     

Nabulsi  Leena  Nguyen  Amy  Odeleye  Oluwatobi 《Journal of Science Education and Technology》2021,30(1):31-39

Journal of Science Education and Technology - Online homework systems have been shown to help student achievement in chemistry courses. This study sought to compare the levels of knowledge...  相似文献   

Unifying different theories of learning: theoretical framework and empirical evidence   总被引：1，自引：1，他引：0  

Huy Phuong Phan 《教育心理学》2008,28(3):325-340

The main aim of this research study was to test out a conceptual model encompassing the theoretical frameworks of achievement goals, study processing strategies, effort, and reflective thinking practice. In particular, it was postulated that the causal influences of achievement goals on academic performance are direct and indirect through study strategies, effort, and reflective thinking. Furthermore, the effects of study strategies on academic performance are hypothesised to be direct and indirect through reflective thinking practice. Participants were 298 (182 females, 116 males) university students. Likert‐response questionnaires were used and data were analysed by means of latent variables approaches. The results provided moderate support for the hypothesised conceptual model. Achievement goals had no direct effects on academic performance, whereas study strategies and reflective thinking directly influenced performance. Mastery goals directly influenced deep processing and effort, whereas performance avoidance and work avoidance influenced surface processing and effort. A one‐way MANOVA indicated, with the exception of understanding, no statistical significance between males and females in the variables. This evidence is theoretically significant as it highlights the mediating mechanism of study strategies and reflective thinking and, more importantly, amalgamates different theoretical frameworks within one study.  相似文献   

Synergizing geriatric research and education in an allied health profession with an older adult community advisory board: development and process outcomes     

An Thi Nguyen  Sharon Burnside  Kristin Junge  Emily Kling Somerville  Marian Keglovits 《Educational gerontology》2020,46(8):486-496

ABSTRACT

Community advisory boards (CABs) have been used to improve research outcomes involving specific communities and populations, including older adults. There is potential to synergize the use of CABs to encompass both research activities and the education of healthcare professionals to help meet increasing demands for a geriatric healthcare workforce in aging populations worldwide. We describe the development and process outcomes of a CAB that synergizes geriatric research and education of students in an allied health profession (occupational therapy). Implementation costs from June 2017–June 2019 were recorded. In-depth interviews were conducted with CAB participants, who were community-dwelling older adults living in St. Louis, Missouri, United States. Interview data were analyzed using a constant comparison method based on a grounded theory approach. Themes were derived regarding barriers, facilitators, and benefits of CAB participation for older adults. Fourteen older adults (aged 65 and over) were initially recruited. The total direct cost of CAB implementation was 4050 United States Dollars over two years. Barriers to CAB participation for older adults included unexpected schedule conflicts due to illness and lack of understanding of the research process, while facilitators included accessible meeting spaces, staff support, flexible participation options, and financial support (e.g., transportation). Perceived benefits of CAB participation included gains in social capital, more positive views of research, and social connectedness. Key lessons learned are described and can be used to inform a novel approach to developing and implementing CABs to improve outcomes of geriatric research and education.  相似文献