Investigating Students' Answering Behaviors in a Computer-Based Mathematics Algebra Test: A Cognitive-Load Perspective.

Computer-based testing is an emerging method to evaluate students' mathematics learning outcomes. However, algebra problems impose a high cognitive load due to requiring multiple calculation steps, which might reduce students' performance in computer-based testing. In order to understand students' cognitive load when answering algebra questions in a computer-based testing environment, three perspectives, element interactivity, practice effect, and individual differences, were investigated in this study. Seven levels of algebra exam questions were created using unary and simultaneous linear equations, and the inverse efficiency scores were employed as a measure of cognitive load in the study. Forty undergraduate and graduate students were tested. There were four findings: (1) As the element interactivity of test materials increased, the cognitive load increased rapidly. (2) The high-efficiency group had a lower cognitive load than the low-efficiency group, suggesting that the high-efficiency group had an advantage in a computer-based testing environment. (3) "Practice" has a considerable effect on reducing cognitive load, particularly in level 6 and 7 test items. (4) The low-efficiency group can reduce but not eliminate the gap with the high-efficiency group; they may require additional experience in a computer-based testing environment in order to improve reducing their cognitive load.

Relative stability of G-quadruplex structures: Interactions between the human Bcl2 promoter region and derivatives of carbazole and diphenylamine.

The bcl2 promoter region forms a G-quadruplex structure, which is a crucial target for anticancer drug development. In this study, we provide theoretical predictions of the stability of different G-quadruplex folds of the 23-mer bcl2 promoter region and G-quadruplex ligand. We take into account the whole G-quadruplex structure, including bound-cations and solvent effects, in order to compute the ligand binding free energy using molecular dynamics simulation. Two series of the carbazole and diphenylamine derivatives are used to screen for the most potent drug in terms of stabilization. The energy analysis identifies the predominant energy components affecting the stability of the various different G-quadruplex folds. The energy associated with the stability of the G-quadruplex-K(+) structures obtained displays good correlation with experimental Tm measurements. We found that loop orientation has an intrinsic influence on G-quadruplex stability and that the basket structure is the most stable. Furthermore, parallel loops are the most effective drug binding site. Our studies also demonstrate that rigidity and planarity are the key structural elements of a drug that stabilizes the G-quadruplex structure. BMVC-4 is the most potential G-quadruplex ligand. This approach demonstrates significant promise and should benefit drug design.

Homology modeling and monoclonal antibody binding of the Der f 7 dust mite allergen.

The group 7 allergens are important allergenic specificities for mite-sensitive patients and may need to be incorporated into new diagnostic and therapeutic strategies. However, little is known about their biological and structural features. Position-specific iterative BLAST showed that they had strong ancestral homology to two related families of lipid-binding proteins, namely, the bactericidal permeability-increasing (BPI) proteins and the odorant-binding protein. A three-dimensional model of Der f 7 made with the Phyre and SWISS-MODEL homology-modeling servers showed a close match with the human BPI coordinates used for its construction. The binding of the monoclonal antibody HD12 known to block IgE binding could be blocked by the linear sequence (46GILDF50) with a critical role for L48 or F50. These hydrophobic residues were located on a surface loop of the model. The properties of Der f 7 that can be deduced from the model provide avenues for further characterizing these allergens, their IgE binding structures and biological properties that can enhance allergenicity.