Stepped vitrification technique for human ovarian tissue cryopreservation

The advantage of stepped vitrification (SV) is avoiding ice crystal nucleation, while decreasing the toxic effects of high cryoprotectant concentrations. We aimed to test this method for human ovarian tissue cryopreservation. Ovarian cortex was taken from 7 fertile adult women. Samples were subjected to an SV protocol performed in an automatic freezer, which allowed sample transfer to ever higher concentrations of dimethyl sulfoxide (DMSO) as the temperature was reduced. Histological evaluation of the vitrified-warmed tissue showed large numbers of degenerated follicles after 24 hours of in vitro culture. We therefore evaluated DMSO perfusion rates by X-ray computed tomography, ice crystal formation by freeze-substitution, and cell toxicity by transmission electron microscopy, seeking possible reasons why follicles degenerated. Although cryoprotectant perfusion was considered normal and no ice crystals were formed in the tissue, ultrastructural analysis detected typical signs of DMSO toxicity, such as mitochondria degeneration, alterations in chromatin condensation, cell vacuolization and extracellular matrix swelling in both stromal and follicular cells. The findings indicated that the method failed to preserve follicles due to the high concentrations of DMSO used. However, adaptations can be made to avoid toxicity to follicles caused by elevated levels of cryoprotectants.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) 2016/22947-

Motivational Social Visualizations for Personalized E-Learning

A large number of educational resources is now available on the Web to support both regular classroom learning and online learning. However, the abundance of available content produces at least two problems: how to help students find the most appropriate resources, and how to engage them into using these resources and benefiting from them. Personalized and social learning have been suggested as potential methods for addressing these problems. Our work presented in this paper attempts to combine the ideas of personalized and social learning. We introduce Progressor + , an innovative Web-based interface that helps students find the most relevant resources in a large collection of self-assessment questions and programming examples. We also present the results of a classroom study of the Progressor +  in an undergraduate class. The data revealed the motivational impact of the personalized social guidance provided by the system in the target context. The interface encouraged students to explore more educational resources and motivated them to do some work ahead of the course schedule. The increase in diversity of explored content resulted in improving students’ problem solving success. A deeper analysis of the social guidance mechanism revealed that it is based on the leading behavior of the strong students, who discovered the most relevant resources and created trails for weaker students to follow. The study results also demonstrate that students were more engaged with the system: they spent more time in working with self-assessment questions and annotated examples, attempted more questions, and achieved higher success rates in answering them

Quality of student-generated learning issues in a problem-based curriculum

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Zelfstudie in probleemgestuurd onderwijs

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The impact of student-generated learning on individual study time and academic achievement

Item does not contain fulltextObjectives The aim of this study was twofold. The first question concerns the way students make use of the learning issues they generate (as strict guidelines or as global guidelines) and whether this changes across years of training. The second question concerned the relationship between the way students make use of learning issues and the time spent on individual study and achievement on two tests of knowledge. Design A questionnaire was developed, containing seven items that measured to what extent students study strictly according to the student-generated learning issues and six items that measured to what extent students study beyond the student-generated learning issues. The questionnaire also contained one question in which students had to estimate the mean time spent on individual study. Achievement was measured by two forms of tests of knowledge, a block test assessing course content and a progress test assessing long-term functional knowledge. Setting Medical School of Maastricht University, the Netherlands. Subjects Medical students (response=69%) from the problem-based curriculum at the Maastricht University. Results During their first year students study strictly according to the content of the learning issues, whereas in later years students studied more according to their own learning needs and interests. In addition, students who tended to study beyond the generated learning issues spent more time on individual study and achieved better on both tests. Conclusions Students in a problem-based curriculum seem to become better self-directed learners during the years of training

Testing a causal model for learning in a problem-based curriculum

Item does not contain fulltextThe aim of this study was to identify the relationship between elements that are important for the tutorial group process and the individual learning process in a problem-based curriculum. The variables under investigation were student-generated learning issues, individual learning process, reporting in the tutorial group, and achievement. A questionnaire containing 22 items was developed. Data were collected in the first year (N = 195) of the Medical School of the Maastricht University in the Netherlands during the academic year 1997-1998. The data were analysed using a structural modelling approach. The results indicate that the model fitted the data well. The path coefficients were moderately high, particular between the explanation-oriented approach and the depth of the reporting in the tutorial group. High path coefficients were also found between the depth of the reporting and achievement. In sum, the model gives insight into how important variables are related and it is recommended that data should be collected to test the model repeatedl

Impact of individual study on tutorial group discussion

Item does not contain fulltextBackground: This research focuses on the relation between individual study and group discussion. In a problem-based curriculum, it is expected that the way students prepare themselves during individual study (i.e., search and prepare the literature) will influence the quality of the reporting phase. Purpose: To investigate whether searching for different literature resources and preparing the literature (by making summaries to explain the literature) affects the quality of the reporting phase. Method: A 23-item questionnaire was developed, reflecting 2 factors of the search phase and 1 factor of the preparing phase of the individual study. Two factors (breadth and depth of the discussion) reflected the reporting phase. Participants were 1st-year students (N = 195, 90%) at the Medical School of the Maastricht University in the Netherlands during the academic year 1997-1998. Results: Regression analyses show that the search phase and the preparing phase explained 29% of the variance of the breadth and 38% of the depth of the reporting phase. Conclusions: Searching different literature resources has a small and negative impact on the quality of the reporting phase. However, preparing extensively for the next tutorial meeting is very important, especially for the depth of the reporting phase. Therefore, when new knowledge must be integrated in the tutorial group, students must be taught to prepare themselves by making summaries that are useful and effective during the discussion