Lessons Learned in Designing Active Learning Modules for the STEM Classroom

For students to become real partners in their education, they must shift from a model of passive absorption of knowledge to one of active participation in constructing knowledge. To encourage this shift, I have designed a variety of active learning modules for my introductory chemistry classes, from short participation polls to full-length case studies. When well-implemented, in-class activities can be a valuable experience for students to practice applying their knowledge with instructor guidance. In this report, I will share both successes and challenges encountered in designing student-friendly active learning modules in an introductory science course

Pan-Cancer Proteogenomics Characterization of Tumor Immunity

Despite the successes of immunotherapy in cancer treatment over recent decades, less than \u3c10%-20% cancer cases have demonstrated durable responses from immune checkpoint blockade. To enhance the efficacy of immunotherapies, combination therapies suppressing multiple immune evasion mechanisms are increasingly contemplated. To better understand immune cell surveillance and diverse immune evasion responses in tumor tissues, we comprehensively characterized the immune landscape of more than 1,000 tumors across ten different cancers using CPTAC pan-cancer proteogenomic data. We identified seven distinct immune subtypes based on integrative learning of cell type compositions and pathway activities. We then thoroughly categorized unique genomic, epigenetic, transcriptomic, and proteomic changes associated with each subtype. Further leveraging the deep phosphoproteomic data, we studied kinase activities in different immune subtypes, which revealed potential subtype-specific therapeutic targets. Insights from this work will facilitate the development of future immunotherapy strategies and enhance precision targeting with existing agents

A Field Guide to Pandemic, Epidemic and Sporadic Clones of Methicillin-Resistant Staphylococcus aureus

In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements

A Field Guide to Pandemic, Epidemic and Sporadic Clones of Methicillin-Resistant Staphylococcus aureus

In recent years, methicillin-resistant Staphylococcus aureus (MRSA) have become a truly global challenge. In addition to the long-known healthcare-associated clones, novel strains have also emerged outside of the hospital settings, in the community as well as in livestock. The emergence and spread of virulent clones expressing Panton-Valentine leukocidin (PVL) is an additional cause for concern. In order to provide an overview of pandemic, epidemic and sporadic strains, more than 3,000 clinical and veterinary isolates of MRSA mainly from Germany, the United Kingdom, Ireland, France, Malta, Abu Dhabi, Hong Kong, Australia, Trinidad & Tobago as well as some reference strains from the United States have been genotyped by DNA microarray analysis. This technique allowed the assignment of the MRSA isolates to 34 distinct lineages which can be clearly defined based on non-mobile genes. The results were in accordance with data from multilocus sequence typing. More than 100 different strains were distinguished based on affiliation to these lineages, SCCmec type and the presence or absence of PVL. These strains are described here mainly with regard to clinically relevant antimicrobial resistance- and virulence-associated markers, but also in relation to epidemiology and geographic distribution. The findings of the study show a high level of biodiversity among MRSA, especially among strains harbouring SCCmec IV and V elements. The data also indicate a high rate of genetic recombination in MRSA involving SCC elements, bacteriophages or other mobile genetic elements and large-scale chromosomal replacements

A Lewis Acidic, π‑Conjugated Stibaindole with a Colorimetric Response to Anion Binding at Sb(III)

We describe 1-chloro-2,3-diphenylstibaindole (<b>1</b>-Cl), a Sb­(III) heterocycle which exhibits visible-wavelength absorption due to conjugation of the σ*­(Sb–Cl) orbital with the π* system of the conjugated backbone. Because the σ*­(Sb–Cl) orbital is accessible, stibaindole <b>1</b>-Cl is a Lewis acid that readily binds halide anions at the site opposite the Sb–Cl bond. This binding induces a “turn-off” colorimetric response due to the suppression of the σ*−π* conjugation in the anion-bound form

Synthesis and Coordination Chemistry of a Phosphine-Decorated Fluorescein: “Double Turn-On” Sensing of Gold(III) Ions in Water

Although phosphine ligands are ubiquitous in transition metal chemistry, few reports of fluorescent phosphines exist that explore the effect of metal coordination on the photophysical properties of a phosphine-bound fluorescent group. The coordination chemistry of a derivative of fluorescein decorated with an <i>o</i>-phenylene-linked phosphine group has been studied with late transition metals. An Au­(I) complex of the phosphine-decorated fluorescein has been structurally characterized, showing that the metal center is held closely over the plane of the fluorophore. Despite the presence of the heavy metal center, however, the phosphine-gold complex displays greatly increased fluorescence compared to the free ligand, in which photoelectron transfer from the lone-pair-bearing phosphine causes low emission. The phosphine-decorated fluorescein ligand was tested in a simple sensing system for metal ions in aqueous solution and shows a “turn-on” response to Au, Ag, and Hg, with an especially dramatic response to Au­(III) species. The selectivity for Au­(III) was determined to be the result of a “double turn-on” response that is both reaction- and coordination-based

Synthesis and Coordination Chemistry of a Phosphine-Decorated Fluorescein: “Double Turn-On” Sensing of Gold(III) Ions in Water

Although phosphine ligands are ubiquitous in transition metal chemistry, few reports of fluorescent phosphines exist that explore the effect of metal coordination on the photophysical properties of a phosphine-bound fluorescent group. The coordination chemistry of a derivative of fluorescein decorated with an <i>o</i>-phenylene-linked phosphine group has been studied with late transition metals. An Au­(I) complex of the phosphine-decorated fluorescein has been structurally characterized, showing that the metal center is held closely over the plane of the fluorophore. Despite the presence of the heavy metal center, however, the phosphine-gold complex displays greatly increased fluorescence compared to the free ligand, in which photoelectron transfer from the lone-pair-bearing phosphine causes low emission. The phosphine-decorated fluorescein ligand was tested in a simple sensing system for metal ions in aqueous solution and shows a “turn-on” response to Au, Ag, and Hg, with an especially dramatic response to Au­(III) species. The selectivity for Au­(III) was determined to be the result of a “double turn-on” response that is both reaction- and coordination-based