Theory to reality: a few issues in implementing problem-based learning

The success of an intervention depends not only upon its theoretical soundness, but also on proper implementation that reflects the guidelines derived from its theoretical conception. Debates surrounding the effectiveness of problem-based learning (PBL) have focused on its theoretical conception and students’ learning outcomes, but implementation is seemingly absent from the picture. This paper attempts to describe what research evidence is needed to fill in this missing information and provide a clearer picture of PBL. The author examines current PBL implementation practices and identifies potentially confounding variables that may play a role in inconsistent or conflicting research results in PBL. For example, various models of PBL have been developed and implemented to afford the specific instructional needs of the institution or learner population. These PBL models are in fact quite different in terms of the nature of problem solving and the degrees of self-directed learning, which theoretically, should result in different types of learning outcomes. Without distinguishing the models used, the results of comparative PBL research could have been confounded. Furthermore, human factors are another set of confounding variables that could influence the students’ learning processes and consequently affect PBL implementations and research results. To remedy these problems and reach PBL’s full potential, as well as obtain a more accurate picture of PBL as an instructional method and its effects on students’ learning, some fundamental changes are needed.     

An integrated microfluidic system for screening of phage-displayed peptides specific to colon cancer cells and colon cancer stem cells

Affinity reagents recognizing biomarkers specifically are essential components of clinical diagnostics and target therapeutics. However, conventional methods for screening of these reagents often have drawbacks such as large reagent consumption, the labor-intensive or time-consuming procedures, and the involvement of bulky or expensive equipment. Alternatively, microfluidic platforms could potentially automate the screening process within a shorter period of time and reduce reagent and sample consumption dramatically. It has been demonstrated recently that a subpopulation of tumor cells known as cancer stem cells possess high drug resistance and proliferation potential and are regarded as the main cause of metastasis. Therefore, a peptide that recognizes cancer stem cells and differentiates them from other cancer cells will be extremely useful in early diagnosis and target therapy. This study utilized M13 phage display technology to identify peptides that bind, respectively, to colon cancer cells and colon cancer stem cells using an integrated microfluidic system. In addition to positive selection, a negative selection process was integrated on the chip to achieve the selection of peptides of high affinity and specificity. We successfully screened three peptides specific to colon cancer cells and colon cancer stem cells, namely, HOLC-1, HOLC-2, and COLC-1, respectively, and their specificity was measured by the capture rate between target, control, and other cell lines. The capture rates are 43.40 ± 7.23%, 45.16 ± 7.12%, and 49.79 ± 5.34% for colon cancer cells and colon cancer stem cells, respectively, showing a higher specificity on target cells than on control and other cell lines. The developed technique may be promising for early diagnosis of cancer cells and target therapeutics.     

Is small actually big? The chaos of technological change

In this paper, we develop themes from complexity and chaos theory that help to explain the technological change process. We apply two quantifiers, correlation dimensions and Lyapunov exponents, to examine the signs and degrees of chaotic technological dynamics. To illustrate our ideas, we study the development of electronic displays from 1976 to 2010, using patent data. The results of the chaos model are matched against the profiles of patent citations. Our analysis contributes to the development of a chaotic model of technological change.     

对21世纪我国高校网球热的预测

网球运动历史悠久，是世界上开展得十分广泛且深受人们喜爱的一项体育运动。随着我国改革开放的深入，人民生活水平的提高，网球运动逐渐普及，以其固有的价值和魅力，受到大学生们的青睐，在２１世纪我国高校将掀起网球热。本文较详细地阐述了掀起网球热的理由。     

Exploring the characteristics of an optimal design of non-programming plugged learning for developing primary school students’ computational thinking in mathematics

Existing computational thinking (CT) research focuses on programming in K-12 education; however, there are challenges in introducing it into the formal disciplines. Therefore, we propose the introduction of non-programming plugged learning in mathematics to develop students’ CT. The research and teaching teams collaborated to develop an instructional design for primary school students. The participants were 112 third- and fourth-grade students (aged 9–10) who took part in three rounds of experiments. In this paper, we present an iterative problem-solving process in design-based implementation research, focusing on the implementation issues that lead to the design principles in the mathematics classroom. The computational tasks, environment, tools, and practices were iteratively improved over three rounds to incorporate CT effectively into mathematics. Results from the CT questionnaire demonstrated that the new program could significantly improve students’ CT abilities and compound thinking. The results of the post-test revealed that CT, including the sub-dimensions of decomposition, algorithmic thinking, and problem-solving improved threefold compared to the pre-test between the three rounds, indicating that strengthened CT design enhanced CT perceptions. Similarly, the students’ and teacher’ interviews confirmed their positive experiences with CT. Based on empirical research, we summarize design characteristics from computational tasks, computational environment and tools, and computational practices and propose design principles. We demonstrate the potential of non-programming plugged learning for developing primary school students’ CT in mathematics.

     

Does evaluating peer assessment accuracy and taking it into account in calculating assessor’s final score enhance online peer assessment quality?

Education and Information Technologies - Peer assessment has an important role in teaching and learning nowadays. However, the existing techniques tend to be limited due to a lack of a suitable...