Evaluation of antioxidant properties of some commercially available culinary and medicinal mushrooms from Taiwan

PhD ThesisA selection of commercially available mushrooms was obtained from Taiwan and screened for phenolic contents and antioxidant activity in aqueous extracts using various chemical measurements, namely scavenging of 2,2´-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical cation (TEAC), Ferric reducing antioxidant power (FRAP), scavenging of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and Folin-Ciocalteu reaction. According to the antioxidant activity perceived, Cordyceps militaris, Pleurotus citrinopileatus, Trametes versicolor, Hericium erinaceus, Ganoderma lucidum and Auricularia auricula-judae were selected for in vitro digestion and cellular antioxidant assay. After the in vitro digestion steps, the antioxidant activity in the extracts of C. militaris had significantly decreased, (in TEAC 22% and 27 % decrease, in hot- and cold-water extracts, respectively, in FRAP 42% and 21% decrease, in hot- and cold-water extracts, respectively and in DPPH 78% and 21% decrease in hot- and cold-water extracts, respectively). The hot-water extract of A. auricula-judae and cold-water extracts of H. erinaceus showed no significant increase in TEAC assay after enzymatic digestion. There was a significant increase in antioxidant activity in the other mushroom extracts after in vitro enzymatic digestion. P. citrinopileatus exhibited the most potent antioxidant activity in the TEAC (from 24 to 2 times higher and 10 to 1.5 times higher than other mushrooms in hot- and cold-water extracts, respectively) and DPPH assays (from 6.4 to 1.2 times higher and from 27 to 1.6 times higher than the other five mushrooms in hot- and cold-water extracts, respectively) after digestion steps. T. versicolor showed the most potent ferric reducing power after digestion steps (from 29 to 5 times higher and 14 to 1.1 times higher than the other five mushrooms in hot- and cold-water extracts, respectively). These results indicate that most of the potential antioxidant compounds within the mushroom extracts could be released after digestion steps, whereas the potential antioxidant compounds of C. militaris might be degraded after digestion steps. The results suggest that determination of antioxidant activity in selected mushroom extracts may underestimate the real antioxidant activity that may be in close contact with the intestinal lumen. Chemical estimates of potential antioxidant compounds within the mushroom extracts may not accurately indicate the complex nature of the antioxidant activity of mushroom extracts within cells. In this study, human hepatoma cell lines (Huh 7) were used to measure cellular antioxidant activity using 2´, 7´- dichlorodihydrofluorescein diacetate as a fluorescent probe. In artificially induced peroxyl radicals, among the selected mushroom extracts tested, C. militaris and T. versicolor had the highest cellular antioxidant activity, whereas H. erinaceus had the lowest. In addition, in chemical assays (TEAC and DPPH), the antioxidant activity of T. versicolor was less than that of P. citrinopileatus (64% and 67 % less in TEAC in hot-and cold- water extracts, respectively and 70% and 82% less in DPPH in hot- and cold-water extracts respectively). Even though the antioxidant activity of C. militaris was decreased after digestion steps, C. militaris exhibited far stronger cellular antioxidant activity than the other five mushrooms (p < 0.001). Based on the different antioxidant assay methods, the antioxidant activity of each antioxidant assay gave different antioxidant trends and antioxidant activity value depending on the type of extract method (hot- and cold-water extracts). Using cellular antioxidant assays may produce bioactivity results of the antioxidant activity of mushroom extracts within cells. These findings could suggest that the aqueous extracts from C. militaris and T. versicolor associated with health benefits and other traditional remedies, at least in part, might be their potent antioxidant activity

Deterministic Dense Coding and Faithful Teleportation with Multipartite Graph States

We proposed novel schemes to perform the deterministic dense coding and faithful teleportation with multipartite graph states. We also find the sufficient and necessary condition of a viable graph state for the proposed scheme. That is, for the associated graph, the reduced adjacency matrix of the Tanner-type subgraph between senders and receivers should be invertible.Comment: 10 pages, 1 figure;v2. discussions improve

The study on the dynamic response of cylindrical pressure hull on the different shock loading empirical formula

[[abstract]]This paper focuses on the comparison between underwater explosion (UNDEX) shock loading empirical formulations. First, the numerical simulations for a cylindrical pressure hull subjected to UNDEX loading were conducted and the results are close to the failure modes shown in experiments of Kwon (1993). Second, the empirical UNDEX loading formula of Cole (1948), Keil (1961) and Shin (1994) used in cylinder subjected to underwater shock loading were compared. The simulation results by using three empirical formulas were compared and Shin’s (or Cole’s) empirical formula was shown to be better than the other empirical formulations when subjected to an UNDEX under the same conditions. The analytical results offer a valuable reference to the research of underwater explosion.[[notice]]補正完

Microblogging for Strengthening a Virtual Learning Community in an Online Course

This paper examines how a microblogging tool (i.e., Twitter) can be effectively used to strengthen a virtual learning community (VLC) in the two sections of a fully online graduate course. Students in this course were consisted of K-12 teachers, school technology specialists, corporate trainers, and military personnel. The microblogging activities were designed to allow quick peer interaction to build the momentum of social learning in the VLC. In this study, we collected quantitative data on sense of community through a Likert scale survey, and rich qualitative data on students\u27 perception about microblogging activities. It was found that students’ sense of community was generally high and students were positive about their microblogging experiences. In addition, microblogging was found to be useful and valuable in sustaining students\u27 learning by doing such as sharing real-world design examples, critiquing design examples with technical knowledge learned in class, and quick and short commenting with peer support in a VLC. Based on the findings, the authors aim to provide design suggestions for educators and instructional designers to incorporate this social web tool in strengthening virtual learning communities in a meaningful and engaging way

Mobile App Design for Teaching and Learning: Educators’ Experiences in an Online Graduate Course

This research explored how educators with limited programming experiences learned to design mobile apps through peer support and instructor guidance. Educators were positive about the sense of community in this online course. They also considered App Inventor a great web-based visual programming tool for developing useful and fully functioning mobile apps. They had great sense of empowerment through developing unique apps by using App Inventor. They felt their own design work and creative problem solving were inspired by the customized mobile apps shared by peers. The learning activities, including sharing customized apps, providing peer feedback, composing design proposals, and keeping design journals (blogging), complemented each other to support a positive sense of community and form a strong virtual community of learning mobile app design. This study helped reveal the educational value of mobile app design activities and the web-based visual programming tool, and the possibility of teaching/learning mobile app design online. The findings can also encourage educators to explore and experiment on the potential of incorporating these design learning activities in their respective settings, and to develop mobile apps for their diverse needs in teaching and learning

Design-Grounded Assessment: A Framework and a Case Study of Web 2.0 Practices in Higher Education

This paper synthesises three theoretical perspectives, including sociocultural theory, distributed cognition, and situated cognition, into a framework to guide the design and assessment of Web 2.0 practices in higher education. In addition, this paper presents a case study of Web 2.0 practices. Thirty-seven online graduate students participated in a small-group collaborative concept mapping activity using Web 2.0 applications (e.g. Webspiration) to construct sophisticated understanding of instructional design processes. The analysis of this case focuses on different assessment strategies adopted to ensure students\u27 successful participation in such technology-rich collaborative context. This case study concludes that a shared goal needs to be in place to establish a purpose of collaboration. The collaborative nature of learning afforded by Web 2.0 applications needs to be acknowledged through the award of grades. That is, both the processes and products of collaborative knowledge construction need to be assessed and formally graded at individual and group levels. This paper also suggests several potential assessment strategies that may enhance smoother Web 2.0 practices, and discusses some possible challenges associated with those strategies

Online Graduate Students’ Preferences of Discussion Modality: Does Gender Matter?

Audio/video discussion has been used increasingly in online courses due to its affordances in enhancing online communication. However, whether learners of different characteristics can benefit from this discussion modality has not been investigated extensively. This study examined whether gender plays a role in learners’ preferences and perceptions of audio/video discussion as compared to text discussion. The survey data of thirty-six participants’ perceptions were collected and studied after they participated in an audio/video discussion activity. The findings show that females preferred audio/video discussion more than males did, and more females reported that audio/video discussion strengthened their connection with peers. The top three benefits of audio/video discussion perceived by females and males are presented in this paper. Overall, using audio/video discussion to augment online communication and to connect learners is likely to be more effective and perceived more positively by female students than male students. The findings in this study could provide implications for sound pedagogical decisions that satisfy student preferences

Learners’ Interpersonal Beliefs and Generated Feedback in an Online Role-Playing Peer-Feedback Activity: An Exploratory Study

Peer feedback affords interaction and critical thinking opportunities for learners in online courses. However, various factors prevent learners from taking advantage of these promising benefits. This study explored learners’ perceptions of the interpersonal factors in a role-playing peer-feedback activity, and examined the types of peer feedback that learners generated when playing a role. Participants were 16 graduate students engaged in an online role-playing peer-feedback activity. The results from survey responses revealed learners’ positive interpersonal beliefs, including psychological safety and trust, toward the role-playing peer-feedback activity. In addition, more than sixty percent of the participants reported being more comfortable critiquing peers’ work when playing a role. The content analysis of the peer-feedback entries indicated that learners were able to generate highly constructive feedback entries. In addition to adding supportive comments, those feedback entries identified problems, asked questions, and provided suggestions. The results show that role-play strategy has great potential to enhance learners’ interpersonal beliefs in peer-feedback activity and their feedback quality

Peer Feedback to Facilitate Project-Based Learning in an Online Environment

There has been limited research examining the pedagogical benefits of peer feedback for facilitating project-based learning in an online environment. Using a mixed method approach, this paper examines graduate students’ participation and perceptions of peer feedback activity that supports project-based learning in an online instructional design course. Our findings indicate that peer feedback can be implemented in an online learning environment to effectively support project-based learning. Students actively participated in the peer feedback activity and responded positively about how the peer feedback activity facilitated their project-based learning experiences. The results of content analysis exploring the peer feedback reveal that learners were mostly supportive of peers’ work and they frequently asked questions to help advance their peers’ thinking. The implications and challenges of implementing peer feedback activity in an online learning environment are discussed

Research Priorities in Mobile Learning: An International Delphi Study

Along with advancing mobile technologies and proliferating mobile devices and applications, mobile learning research has gained great momentum in recent years. While there have been review articles summarizing past research, studies identifying mobile learning research priorities based on experts’ latest insights have been lacking. This study employed the Delphi method to obtain a consensus from experts about areas that are most in need of research in mobile learning. An international expert panel participated in a three-round Delphi process involving two cycles of online questionnaires and feedback reports. Participants responded to the question, “What should be the research priorities for the field of mobile learning over the next 5 years?” Ten research categories were identified and ranked in order of priority: 1) teaching and learning strategies; 2) affordances; 3) theory; 4) settings of learning; 5) evaluation/assessment; 6) learners; 7) mobile technologies and interface design; 8) context awareness and augmented reality; 9) infrastructure and management; and 10) country and digital divide. This study also reported expert-generated research statements for each research category and the importance of these research statements rated by the experts. Selected research papers were summarized to help contextualize the discussions of research categories and statements