Effect of oxygen supply on metabolism of immobilized and suspended Escherichia coli

The effect of reduced oxygen supply on the production of a recombinant protein (plasmid-encoded β-galactosidase) was investigated in Escherichia coli. A novel modified bubble tank reactor was used to provide a direct comparison between immobilized and suspended cells in identical environments except for the immobilization matrix. Decreased oxygen supply led to increased β-galactosidase synthesis by both immobilized and suspended cells. Immobilized cells produced similar amounts of β-galactosidase as the suspended cells. Lactose consumption and acetate production, on a per cell basis, were significantly higher in immobilized cells, suggesting that immobilized cells utilized fermentative metabolism. However, a transport analysis of the immobilized cell system showed that immobilized cells were not subject to either external or internal mass transfer gradients.The effect of reduced oxygen supply on the production of a recombinant protein (plasmid-encoded β-galactosidase) was investigated in Escherichia coli. A novel modified bubble tank reactor was used to provide a direct comparison between immobilized and suspended cells in identical environments except for the immobilization matrix. Decreased oxygen supply led to increased β-galactosidase synthesis by both immobilized and suspended cells. Immobilized cells produced similar amounts of β-galactosidase as the suspended cells. Lactose consumption and acetate production, on a per cell basis, were significantly higher in immobilized cells, suggesting that immobilized cells utilized fermentative metabolism. However, a transport analysis of the immobilized cell system showed that immobilized cells were not subject to either external or internal mass transfer gradients

Xenobiotic metabolizing enzyme activities in rat, mouse, monkey, and human testes. Drug Metab. Dispos

ABSTRACT: The capacity of the testis to metabolize xenobiotlcs has been pro

Engineering education and the development of expertise

BACKGROUND: Although engineering education has evolved in ways that improve the readiness of graduates to meet the challenges of the twenty-first century, national and international organizations continue to call for change. Future changes in engineering education should be guided by research on expertise and the learning processes that support its development. PURPOSE: The goals of this paper are: to relate key findings from studies of the development of expertise to engineering education, to summarize instructional practices that are consistent with these findings, to provide examples of learning experiences that are consistent with these instructional practices, and finally, to identify challenges to implementing such learning experiences in engineering programs. SCOPE/METHOD: The research synthesized for this article includes that on the development of expertise, students' approaches to learning, students' responses to instructional practices, and the role of motivation in learning. In addition, literature on the dominant teaching and learning practices in engineering education is used to frame some of the challenges to implementing alternative approaches to learning. CONCLUSION: Current understanding of expertise, and the learning processes that develop it, indicates that engineering education should encompass a set of learning experiences that allow students to construct deep conceptual knowledge, to develop the ability to apply key technical and professional skills fluently, and to engage in a number of authentic engineering projects. Engineering curricula and teaching methods are often not well aligned with these goals. Curriculum-level instructional design processes should be used to design and implement changes that will improve alignment. © 2011 ASEE

Developing Elementary Students’ Digital Literacy Through Augmented Reality Creation: Insights From a Longitudinal Analysis of Questionnaires, Interviews, and Projects

This mixed-method case study investigated digital literacy (DL) development among 32 elementary-level students who created multimodal, contextual, and interactive augmented reality (AR) artifacts in a 20-week after-school program in Northern Taiwan. The instructional design combined situated and spiral learning experiences with AR, implemented through a blended learning environment. Data sources included pre- and post-program digital learning student surveys, student and teacher interviews, classroom observations, and AR artifact assessments. Results indicated statistically significant increases with moderate effect sizes in five areas of students’ DL practices: information management; collaboration; communication and sharing; creation; and evaluation and problem-solving. Students did not increase DL in one area: ethics and responsibility. The situated and spiral learning-by-design approach offered increasingly complex AR creation projects in which students developed and transferred their DL. The face-to-face and online learning settings offered multiple ways to collaborate and facilitated the development of students’ DL. The AR technology enabled students to develop DL through designing AR using three types of representation features: multimodal, interactive, and contextual. Practical and theoretical implications for adapting or enhancing this instructional design in future DL programs and for future research are discussed