JOB SUMMARY: Under limited supervision coordinates and supervises the work activities of lower level machinists and other skilled workers, primarily within the CETL shop which supports research and te...

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Hydrolytic PuO2 nanoparticles (NPs) are a dominant aqueous Pu-bearing phase in high ionic strength nuclear wastes, yet their reactivity in nonideal brines remains poorly constrained. We quantify how electrolyte identity and concentration control PuO2 NP aggregation and ligand-assisted dissolution in acidic, high salinity solutions (NaCl, NaNO3, NaClO4, Na2SO4, Na2C2O4 up to 5 M). A multitechnique workflow combining liquid scintillation counting (operationally defined aqueous [Pu]), scattering/electrokinetic measurements (aggregate size and zeta potential), and spectroscopy (UV–vis, XPS, Raman) resolves electrolyte-dependent partitioning between colloidal and molecular Pu species. Weakly coordinating anions (ClO4–, Cl–, NO3–) largely preserve the (aggregated) nanoparticulate fraction but generate distinct dissolved species at high concentration, i.e., Pu(IV)–nitrato complexes in NaNO3 and Pu(VI)–chloro complexes in NaCl. In contrast, stronger ligands substantially perturb PuO2 NP stability: sulfate promotes partial dissolution to Pu(IV)–sulfate complexes at low concentration but reduces aqueous [Pu] at higher sulfate levels via secondary Pu(IV) sulfate formation, whereas oxalate drives strong dissolution to aqueous Pu–oxalate complexes. Aged NPs show similar trends with reduced aqueous fractions and more dominant aggregation mechanisms. These spectroscopically constrained speciation data provide a foundation for incorporating PuO2 NP reactivity into thermodynamic and reactive transport models for high salinity waste and brine environments.

Antimicrobial resistance in enteric pathogens demands biotechnology-enabled strategies that enhance the efficacy of oral antibiotics while mitigating toxicity and resistance selection. Preclinical evaluation is hindered by reliance on animal models and two-dimensional (2D) cultures that incompletely recapitulate human intestinal architecture, mucus barriers, and infection dynamics. Here, a three-dimensional (3D) villus-mimetic intestinal model based on polydopamine-coated polydimethylsiloxane scaffolds was established as a biomimetic platform to assess advanced nanoparticle-antibiotic drug delivery systems. Zein nanoparticles were formulated into biodegradable carriers encapsulating the fluoroquinolone Enrofloxacin and tested in porcine IPEC-J2 epithelial cells infected with enteropathogenic Escherichia coli O157:H7. Enrofloxacin-loaded Zein carriers achieved the greatest reduction in bacterial burden across both 2D and 3D cultures at a biocompatible dose compared with free drug and empty carriers, indicating improved antimicrobial performance. The 3D scaffolds promoted enhanced epithelial differentiation and mucin production and showed a trend toward lower Icam-1 and Tnf-α induction after infection and treatment relative to 2D monolayers, suggesting a more physiologic mucosal and inflammatory profile. These data position the 3D villus-mimetic system as an integrated biotechnology platform that links infection biology, epithelial function, and drug delivery performance in a single assay. The approach offers a scalable route to preclinical screening of protein-based oral antibiotic carriers and other biotechnology-driven interventions targeting intestinal infections and antimicrobial resistance.