A review on 3D printing functional brain model

Modern neuroscience increasingly relies on 3D models to study neural circuitry, nerve regeneration, and neural disease. Several different biofabrication approaches have been explored to create 3D neural tissue model structures. Among them, 3D bioprinting has shown to have great potential to emerge as a high-throughput/high precision biofabrication strategy that can address the growing need for 3D neural models. Here, we have reviewed the design principles for neural tissue engineering. The main challenge to adapt printing technologies for biofabrication of neural tissue models is the development of neural bioink, i.e., a biomaterial with printability and gelation properties and also suitable for neural tissue culture. This review shines light on a vast range of biomaterials as well as the fundamentals of 3D neural tissue printing. Also, advances in 3D bioprinting technologies are reviewed especially for bioprinted neural models. Finally, the techniques used to evaluate the fabricated 2D and 3D neural models are discussed and compared in terms of feasibility and functionality.     

A Systematic Review of Interventions for Algebraic Concepts and Skills of Secondary Students with Learning Disabilities

Improving the algebraic concepts and skills of secondary school students with learning disabilities is critical for their success in college and in the job market. This research reviewed 12 studies to examine interventions for students with learning disabilities in relation to algebraic notions and competencies. The results indicate that in regard to the Common Core State Standards for Mathematics (CCSSM) Content Standards, the majority of the studies address linear equations and expressions, linear inequalities, and quadratic expressions; they show that following interventions, students’ performance improved with respect to algebraic concepts and skills. The Tau-U and Hedges’ g of the intervention effects computed were typically large or very large. The most commonly used instructional components in the interventions were multiple representations, a sequence and/or range of examples, and explicit instruction. Limitations and suggestions for future research are discussed.     

Testing one premise of scientific inquiry in science classrooms: Examining students' scientific explanations and student learning

In this study, we analyzed the quality of students' written scientific explanations found in notebooks and explored the link between the quality of the explanations and students' learning. We propose an approach to systematically analyzing and scoring the quality of students' explanations based on three components: claim, evidence to support it, and a reasoning that justifies the link between the claim and the evidence. We collected students' science notebooks from eight science inquiry‐based middle‐school classrooms in five states. All classrooms implemented the same scientific‐inquiry based curriculum. The study focuses on one of the implemented investigations and the students' explanations that resulted from it. Nine students' notebooks were selected within each classroom. Therefore, a total of 72 students' notebooks were analyzed and scored using the proposed approach. Quality of students' explanations was linked with students' performance in different types of assessments administered as the end‐of‐unit test: multiple‐choice test, predict‐observe‐explain, performance assessment, and a short open‐ended question. Results indicated that: (a) Students' written explanations can be reliably scored with the proposed approach. (b) Constructing explanations were not widely implemented in the classrooms studied despite its significance in the context of inquiry‐based science instruction. (c) Overall, a low percentage of students (18%) provided explanations with the three expected components. The majority of the sample (40%) provided only claims without any supporting data or reasoning. And (d) the magnitude of the correlations between students' quality of explanations and their performance, were all positive but varied in magnitude according to the type of assessment. We concluded that engaging students in the construction of high quality explanations may be related to higher levels of student performance. The opportunities to construct explanations in science‐inquiry based classrooms, however, seem to be limited. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 583–608, 2010     

Destruction of hexafluoroethane in a dielectric-packed bed plasma reactor

The destruction of hexafluoroethane （C2F6）, also known as R- 116, was investigated in a nonthermal plasma reactor packed with dielectric pellets. The effects of the feed gas composition and the input power on the destruction of C2F6 were examined. The feed gas composition was varied by changing the oxygen content, the argon content and the initial C2F6 concentration. An increased input power led to increased C2F6 destruction as a result of promoting the electron-molecule collisions to dissociate C2F6 molecules. The addition of argon to the feed gas greatly improved the C2F6 destruction by reducing the energy losses due to vibrational excitation and dissociation of N2 molecules, while the increases in the oxygen content and the initial C2F6 concentration decreased the destruction efficiency. The byproducts including CO2, CO, COF2, CF4, SiF4, NO2, and N2O were identified, and the destruction mechanisms were elucidated, referring to these compounds. The most abundant byproduct was found to be carbonyl fluoride （COF2）, indicating that it serves as an important medium to convert C2F6 into CO2. The energy requirement for the C2F6 destruction was in the range of 8.2-45.3 MJ/g, depending on the initial concentration.     

Counting absolute numbers of items,from 1 to 8, in pigeons

Pigeons were trained in a forced choice task with four alternatives to categorize arrays consisting of 1, 3, 5, or 8 dots. Before the pigeons chose a comparison stimulus, they were required to peck each dot sequentially. A single peck to a dot, which was defined as an indicating response, changed the color of the dot so that it was differentiated from those that remained to be counted. The pigeons successfully learned to categorize the numerical arrays and then displayed transfer to novel arrays consisting of two, four, six, or seven dots, in a manner according to the order of 1 < 2 < 3 < 4 < 5 < 6 < 7 < 8. Subsequent tests revealed that the pigeons discriminated the stimuli by relying on the number of indicating responses. They also utilized multiple information (surface area, time, and other confounded events), but this was of minor significance, and after training, the pigeons were able to disregard these cues.     

Classifying higher education institutions in Korea: a performance-based approach

The purpose of this study was to classify higher education institutions according to institutional performance rather than predetermined benchmarks. Institutional performance was defined as research performance and classified using Hierarchical Cluster Analysis, a statistical method that classifies objects according to specified classification factors. In the analysis, 47 Korean universities with doctoral programs were classified as research universities (seven universities), research active universities (14 universities), and doctoral universities (26 universities). In the detailed discussions, profiles of each group were analyzed and discussed; and, disciplinary classifications were conducted in engineering, natural science, and social science and humanities. In addition, to validate the classifications, the research performances of these categories were compared with those of U.S. peers. In the comparisons, the research performance of Korean universities was similar to that of U.S. peers. From the analysis, the classification results emerging from the performance-based approach were shown to be equivalent to that of conventional classifications using predetermined benchmarks.

Growth of Social Competence During the Preschool Years: A 3‐Year Longitudinal Study

This study examined the stability and growth over a 3‐year period of individual differences in preschool children's social competence, which was assessed in three domains: social engagement/motivation, profiles of behavior and personality attributes characteristic of socially competent young children, and peer acceptance. A total of 255 children (126 girls and 129 boys) participated in this study. Growth curve analyses demonstrated both stability and change with regard to social competence over early childhood. Social competence measures and latent variables were invariant over this time period, individual differences in social competence were largely stable from year to year, and significant increases over time were observed for the domain most closely reflective of specific personal attributes skills.