Using consensual qualitative research, the study examines urban high school students' reactions to a science, technology, engineering, and math (STEM) enrichment/ career development program, their resources and barriers, their perspectives on the impact of race and gender on their career development, and their overall views of work and their futures. The sample included nine students who participated in a semistructured interview at the end of the 2-week summer program and again 12-18 months later. The results indicate that the students continued to explore STEM fields after the summer program, reported increases in STEM knowledge, described strong identifications with their racial and gender-based identities, and identified relevant resources and barriers affecting their STEM education and career development. Suggestions for further research and program development are discussed, including the development of interventions to enhance the supportive elements of students' relational and educational contexts.

Biofilms are sessile microbial communities that cause serious chronic infections with high morbidity and mortality. In order to develop more effective approaches for biofilm control, a series of linear cationic antimicrobial peptides (AMPs) with various arginine (Arg or R) and tryptophan (Trp or W) repeats [(RW) n -NH 2 , where n ‫؍‬ 2, 3, or 4] were rigorously compared to correlate their structures with antimicrobial activities affecting the planktonic growth and biofilm formation of Escherichia coli. The chain length of AMPs appears to be important for inhibition of bacterial planktonic growth, since the hexameric and octameric peptides significantly inhibited E. coli growth, while tetrameric peptide did not cause noticeable inhibition. In addition, all AMPs except the tetrameric peptide significantly reduced E. coli biofilm surface coverage and the viability of biofilm cells, when added at inoculation. In addition to inhibition of biofilm formation, significant killing of biofilm cells was observed after a 3-hour treatment of preformed biofilms with hexameric peptide. Interestingly, treatment with the octameric peptide caused significant biofilm dispersion without apparent killing of biofilm cells that remained on the surface; e.g., the surface coverage was reduced by 91.5 ؎ 3.5% by 200 M octameric peptide. The detached biofilm cells, however, were effectively killed by this peptide. Overall, these results suggest that hexameric and octameric peptides are potent inhibitors of both bacterial planktonic growth and biofilm formation, while the octameric peptide can also disperse existing biofilms and kill the detached cells. These results are helpful for designing novel biofilm inhibitors and developing more effective therapeutic methods.

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