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  1. Synaptic plasticity relies on rapid, yet spatially precise signaling to alter synaptic strength. Arc is a brain enriched protein that is rapidly expressed during learning-related behaviors and is essential for regulating metabotropic glutamate receptor-mediated long-term depression (mGluR-LTD). We previously showed that disrupting the ubiquitination capacity of Arc enhances mGluR-LTD; however, the consequences of Arc ubiquitination on other mGluR-mediated signaling events is poorly characterized. Here we find that pharmacological activation of Group I mGluRs with S-3,5-dihydroxyphenylglycine (DHPG) increases Ca2+release from the endoplasmic reticulum (ER). Disrupting Arc ubiquitination on key amino acid residues enhances DHPG-induced ER-mediated Ca2+release. These alterations were observed in all neuronal subregions except secondary branchpoints. Deficits in Arc ubiquitination altered Arc self-assembly and enhanced its interaction with calcium/calmodulin-dependent protein kinase IIb (CaMKIIb) and constitutively active forms of CaMKII in HEK293 cells. Colocalization of Arc and CaMKII was altered in cultured hippocampal neurons, with the notable exception of secondary branchpoints. Finally, disruptions in Arc ubiquitination were found to increase Arc interaction with the integral ER protein Calnexin. These results suggest a previously unknown role for Arc ubiquitination in the fine tuning of ER-mediated Ca2+signaling that may support mGluR-LTD, which in turn, may regulate CaMKII and its interactions with Arc.

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  2. Spatial skills are fundamental to learning and developing expertise in engineering. This paper describes a new virtual and physical manipulatives (VPM) technology that this research team recently developed to enhance undergraduate engineering students’ spatial skills. This technology consists of ten manipulatives spanning a variety of levels of geometrical complexity. Each manipulative is authentic due to their real-world engineering applications that were chosen to stimulate student interest in engineering. A computer program was developed to connect virtual and physical manipulatives, allowing students to receive spatial training anytime, anywhere through the Internet. Quasi-experimental research, involving an intervention group (n = 37) and a control group (n = 34), was conducted. Each group completed a pre- and post-test using the same assessment instrument that measured students’ spatial skills. Normality tests were conducted. The results show that the data involved in the present study did not have a normal distribution. Thus, non-parametric statistical analysis was performed, including descriptive analysis, correlation analysis, and Mann-Whitney U tests. The results show that the mean value of normalized learning gains is 41.2% for the intervention group, which is 33% higher than that for the control group (8.2%). A statistically significant difference exists between the intervention and control groups in terms of normalized learning gains (P < 0.01). The new VPM technology developed from the present study has a medium effect size (0.34) on improving students’ spatial skills. 
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  3. Computer simulation and animation (CSA) is educational technology in which computer programs are employed to simulate and animate real-world physical phenomena and processes. CSA has attracted growing attention and received an increasing number of applications in the international science, technology, engineering, and mathematics education community in recent years. The present study focuses on developing and assessing two CSA learning modules for improving student learning and problem-solving related to impulse and momentum in particle dynamics. Both CSA learning modules integrate mathematical problem-solving procedures into computer simulation and animation. They have interactive computer graphical user interfaces, which enable students to change input variables and visualize how output variables change accordingly. A quasi-experimental, quantitative research study was performed, involving 285 undergraduate engineering students divided into a comparison group that did not use CSA and an intervention group that used CSA. The results of statistical non-parametric analysis on the data collected from pre- and post-tests on the two groups show that, on average, the intervention group achieved more learning gains than the comparison group by 44% and 40% from two CSA learning modules, respectively. The difference in learning gains between the two groups of student participants was statistically significant.

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  4. The current study examined the neural correlates of spatial rotation in eight engineering undergraduates. Mastering engineering graphics requires students to mentally visualize in 3D and mentally rotate parts when developing 2D drawings. Students’ spatial rotation skills play a significant role in learning and mastering engineering graphics. Traditionally, the assessment of students’ spatial skills involves no measurements of neural activity during student performance of spatial rotation tasks. We used electroencephalography (EEG) to record neural activity while students performed the Revised Purdue Spatial Visualization Test: Visualization of Rotations (Revised PSVT:R). The two main objectives were to 1) determine whether high versus low performers on the Revised PSVT:R show differences in EEG oscillations and 2) identify EEG oscillatory frequency bands sensitive to item difficulty on the Revised PSVT:R.  Overall performance on the Revised PSVT:R determined whether participants were considered high or low performers: students scoring 90% or higher were considered high performers (5 students), whereas students scoring under 90% were considered low performers (3 students). Time-frequency analysis of the EEG data quantified power in several oscillatory frequency bands (alpha, beta, theta, gamma, delta) for comparison between low and high performers, as well as between difficulty levels of the spatial rotation problems.   Although we did not find any significant effects of performance type (high, low) on EEG power, we observed a trend in reduced absolute delta and gamma power for hard problems relative to easier problems. Decreases in delta power have been reported elsewhere for difficult relative to easy arithmetic calculations, and attributed to greater external attention (e.g., attention to the stimuli/numbers), and consequently, reduced internal attention (e.g., mentally performing the calculation). In the current task, a total of three spatial objects are presented. An example rotation stimulus is presented, showing a spatial object before and after rotation. A target stimulus, or spatial object before rotation is then displayed. Students must choose one of five stimuli (multiple choice options) that indicates the correct representation of the object after rotation. Reduced delta power in the current task implies that students showed greater attention to the example and target stimuli for the hard problem, relative to the moderate and easy problems. Therefore, preliminary findings suggest that students are less efficient at encoding the target stimuli (external attention) prior to mental rotation (internal attention) when task difficulty increases.  Our findings indicate that delta power may be used to identify spatial rotation items that are especially challenging for students. We may then determine the efficacy of spatial rotation interventions among engineering education students, using delta power as an index for increases in internal attention (e.g., increased delta power). Further, in future work, we will also use eye-tracking to assess whether our intervention decreases eye fixation (e.g., time spent viewing) toward the target stimulus on the Revised PSVT:R. By simultaneously using EEG and eye-tracking, we may identify changes in internal attention and encoding of the target stimuli that are predictive of improvements in spatial rotation skills among engineering education students.  
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  5. Abstract

    Nanoconfinement could dramatically change molecular transport and reaction kinetics in heterogeneous catalysis. Here we specifically design a core-shell nanocatalyst with aligned linear nanopores for single-molecule studies of the nanoconfinement effects. The quantitative single-molecule measurements reveal unusual lower adsorption strength and higher catalytic activity on the confined metal reaction centres within the nanoporous structure. More surprisingly, the nanoconfinement effects on enhanced catalytic activity are larger for catalysts with longer and narrower nanopores. Experimental evidences, including molecular orientation, activation energy, and intermediate reactive species, have been gathered to provide a molecular level explanation on how the nanoconfinement effects enhance the catalyst activity, which is essential for the rational design of highly-efficient catalysts.

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