RESUMO
Supporting students with upholding the principles of academic integrity is an important aspect of teaching. Academic integrity is especially important in chemistry laboratory classrooms, where students gain hands-on experience related to research and scientific practices. Prior literature on academic integrity largely focuses on catching and preventing cheating, describing various factors commonly associated with cheating behaviors. This body of literature assumes that students neutralize their feelings about cheating to engage in unethical behavior. In contrast, for this study, we began with the assumption that students intend to act ethically; to this end, we sought to investigate students' perceptions, evaluations, and motivations related to cheating and academic integrity. We interviewed 24 students enrolled in general chemistry laboratories and asked questions related to cheating and academic integrity. Additionally, to address concerns about social desirability bias affecting students' responses, we asked students questions involving hypothetical scenarios related to academic integrity that were contextualized within the chemistry laboratory classroom. In our analysis, we found that students held common views about cheating and academic integrity in general but diverged in their responses to the hypothetical scenarios. Our findings suggest the importance of providing clearer, more direct instruction regarding what counts as cheating and how to engage in academically honest behavior within the chemistry laboratory classroom.
RESUMO
Five series of chromans with urea and thiourea linkers connecting a chroman unit (ring A) and a 4-substituted benzene unit (ring B) have been prepared and evaluated relative to SHetA2 (NSC 721689) for activity against the human A2780 ovarian cancer cell line. The lead compound SHetA2 had a sulfur in place of the oxygen in ring A and a thiourea linker to ring B. The 2-Me-4-Me series (two sets of geminal dimethyl groups at C2 and at C4 on the ring A unit) permitted direct comparison with SHetA2. Ring B in this series was evaluated with specific functional groups at C4 on the ring, including NO2, CO2Et, CF3, OCF3, CN and SO2NH2. The 2-H-4-Me series (only one geminal dimethyl group at the C4 position on ring A) permitted structure-activity relationship analysis to assess the importance of the hydrophobic geminal dimethyl groups on ring A to the activity of SHetA2. The remaining three series 2-Et-4-Me, 2-Me-4-Et and 2-Et-4-Et (ring A methyl groups replaced with ethyls at C2, at C4 and at both C2 and C4, respectively) offered the opportunity to modulate the hydrophobicity of the chroman moiety. Additionally, in all these series, the influence of a urea versus a thiourea linker was also investigated. The results of these modifications are summarized below. The exact analog of SHetA2 with oxygen substituted for sulfur in ring A (2a) showed comparable efficacy but a significantly lower IC50 against the ovarian cancer cell line. The urea linked analogs bearing CN, CF3 and OCF3 at C4 of ring B (3c,d and f) showed greater efficacy than SHetA2, but also had lower IC50 values. Removing the geminal dimethyl group at C2 (4a-c, 5a-c) caused a significant lowering of the efficacy and percent growth inhibition, indicating that the hydrophobic geminal dimethyl group at C2 in ring A is crucial for activity. Finally, replacing the geminal dimethyl groups with geminal diethyls on ring A in the urea derivatives gave 6b-c, 7c-d and 8b, all of which outperformed SHetA2 with respect to efficacy and IC50. The results for compounds 4-8 are in concurrence with modeling studies, which predicted that greater hydrophobicity in ring A would be beneficial. Binding energies were determined for compounds docked in silico to mortalin, the protein identified as a receptor of SHetA2. The urea linker promoted activity comparable to or, in some cases, greater than compounds with a thiourea linker. Several compounds achieved 94% efficacy and an IC50 of 2⯵M, which were better than SHetA2 (84%, 3⯵M).
