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The sudden transition from in-person to virtual learning during the spring 2020 semester posed challenges for students and faculty alike. This paper explores the techniques used by faculty to transform the chemistry and biochemistry curriculum at a Hispanic-serving institution with a significant proportion of first-generation students and the response of students to these changes. Faculty utilized an assortment of techniques, including synchronous lectures by video conference, asynchronous prerecorded lectures, online examinations with varying timing policies, and virtual office hours. A survey was completed by 332 students across 26 different courses taught by 11 faculty regarding their preferences for course delivery format and the academic and nonacademic challenges they faced. A paired samples "t"-test indicated a statistically significant difference in satisfaction with face-to-face instruction (M = 4.13, SD = 0.765) and satisfaction with virtual instruction (M = 3.57, SD = 0.961), t(440) = 13.30, p < 0.001, Cohen's "d" of 0.63, and Cronbach's [alpha] of 0.767. The results indicated a preference for face-to-face instruction. Open-ended survey questions identify that the primary academic challenges faced by students involved technology, understanding material, and difficulty obtaining help, while the primary nonacademic challenges were work issues, focus/motivation, and family issues. These results may inform future practices for virtual instruction.

Science educators have developed a variety of assessment techniques to help students connect their scientific knowledge and bridge conceptual gaps. In chemistry, concept maps and creative exercises are the two notable assessments that have been implemented into multiple chemistry courses and indicated promising effects on students' conceptual learning and connection-making between chemistry concepts. These two assessment techniques were usually implemented individually in research studies. Herein, we employed a quasi-experimental, mixed-methods approach to explore whether combining concept maps and creative exercises would reveal any synergistic effects for student learning of chemical equilibrium and acid-base chemistry in a college general chemistry course. In this study, student perceptions of the use of the two assessments were examined by open-ended surveys. Interestingly, students perceived creative exercises as an assessment technique while concept maps were viewed as a learning tool for studying or reviewing exams. Additionally, Students believed that concept maps assisted them in answering creative exercises, but not vice versa. The four study groups (control group, concept maps only, creative exercises only, and both concept maps and creative exercises) were compared through concept inventory pre and post-test questions. The results of an ANCOVA indicated that participation in the experimental groups did not significantly impact conceptual learning gains, as measured by the concept inventory post-test scores. However, focus group interviews indicated students from the experimental group that used both concept maps and creative exercises were able to provide more sophisticated scientific explanations for conceptual questions related to the topics of chemical equilibrium and acid-base chemistry. Implications of these research results, best practices for implementation of the two assessments, and future research are discussed.

In an effort to improve student conceptual understanding and help students better connect pre-existing knowledge to new ideas, a concept map assignment was implemented in a first-year college level general chemistry course. This implementation included a quasi-experiment that was carried out in discussion group recitation sections within a third-quarter general chemistry course. Students enrolled in a single section of the course were divided into two groups in which a concept map treatment was compared to a control group that completed short journal entries. Comparison of a concept inventory post-test using an independent samples t-test indicates students in the concept map treatment appear to perform better than the students in the journal control group (t = 2.34, mean difference = 0.844, p < 0.05). However, a multi-variable regression analysis in which the concept inventory post-test scores were compared between the treatment and control groups, while traits related to incoming academic preparation were held constant, suggests there was no significant difference in performance (unstandardized b = 0.222, p = 0.540). The quality of the students' concept maps was also evaluated and correlated to student performance on the concept inventory, and it appears students who were better at concept mapping made greater gains in conceptual understanding (Pearson's r = 0.295, p < 0.05). When the relationship between the quality of concept mapping and concept inventory post-test was determined while holding constant covariates related to incoming academic preparation, the unstandardized B coefficient was positive, but was not significant at the p = 0.05 level (unstandardized b = 0.215, p = 0.134) This study does not provide unequivocal evidence that a concept map treatment leads to greater gains in conceptual understanding compared to a control population, or that students with better concept mapping skills performed better on the concept inventory instrument. Nevertheless, a template for implementing a concept map assignment in a large enrollment course is provided, and the results presented herein might prompt chemistry instructors to consider including concept map assignments in their instructional toolbox.

Disulfide heterogeneity and other non-native crosslinks introduced during therapeutic antibody production and storage could have considerable negative effects on clinical efficacy, but tracking these modifications remains challenging. Analysis must also be carried out cautiously to avoid introduction of disulfide scrambling or reduction, necessitating the use of low pH digestion with less specific proteases. Herein we demonstrate that 213 nm ultraviolet photodissociation streamlines disulfide elucidation through bond-selective dissociation of sulfur–sulfur and carbon–sulfur bonds in combination with less specific backbone dissociation. Importantly, both types of fragmentation can be initiated in a single MS/MS activation stage. In addition to disulfide mapping, it is also shown that thioethers and trisulfides can be identified by characteristic fragmentation patterns. The photochemistry resulting from 213 nm excitation facilitates a simplified, two-tiered data processing approach that allows observation of all native disulfide bonds, scrambled disulfide bonds, and non-native sulfur-based linkages in a pepsin digest of Rituximab. Native disulfides represented the majority of bonds according to ion count, but the highly solvent-exposed heavy/light interchain disulfides were found to be most prone to modification. Production and storage methods that facilitate non-native links are discussed. Due to the importance of heavy and light chain connectivity for antibody structure and function, this region likely requires particular attention in terms of its influence on maintaining structural fidelity. [ABSTRACT FROM AUTHOR]