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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,423 records · Page 79
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Selective Labeling and Decoration of the Ends and Sidewalls of Single-Walled Carbon Nanotubes Using Mono- and Bispecific Solid-Binding Fluorescent Proteins

Simple and robust strategies for the noncovalent functionalization of carbon nanostructures with proteins are of considerable interest in hybrid nanomaterials synthesis, part-to-part assembly, and biosensor development. In this work, we show that fusion of the Car9 and Car15 carbon-binding peptides to the C-termini of the sfGFP and mCherry fluorescent proteins enables selective labeling of the ends or the sidewalls of single walled carbon nanotubes. By installing a gold-binding peptide or a single cysteine residue in carbon-binding variants of sfGFP, we further produce heterobifunctional solid-binding proteins that support the decoration of nanotubes sidewalls or termini with gold nanoparticles. The approach described here is generic and should prove useful for the controlled assembly of other hybrid materials.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Geobacter sp. Strain IAE Dihaloeliminates 1,1,2-Trichloroethane and 1,2-Dichloroethane

We report that chlorinated ethanes, including 1,2-dichloroethane (1,2-DCA) and 1,1,2-trichloroethane (1,1,2-TCA), are widespread groundwater contaminants. Enrichment cultures XR DCA and XR TCA derived from river sediment dihaloeliminated 1,2-DCA to ethene and 1,1,2-TCA to vinyl chloride (VC), respectively. The XR TCA culture subsequently converted VC to ethene via hydrogenolysis. Microbial community profiling demonstrated the enrichment of Geobacter 16S rRNA gene sequences in both the XR DCA and XR TCA cultures, and Dehalococcoides mccartyi (Dhc) sequences were only detected in the ethene-producing XR TCA culture. The presence of a novel Geobacter population, designated as Geobacter sp. strain IAE, was identified by the 16S rRNA gene-targeted polymerase chain reaction and Sanger sequencing. Time-resolved population dynamics attributed the dihaloelimination activity to strain IAE, which attained the growth yields of 0.93 ± 0.06 x 10 7 and 1.18 ± 0.14 x 10 7 cells per μmol Cl -1 released with 1,2-DCA and 1,1,2-TCA as electron acceptors, respectively. In contrast, Dhc growth only occurred during VC-to-ethene hydrogenolysis. Our findings discover a Geobacter sp. strain capable of respiring multiple chlorinated ethanes and demonstrate the involvement of a broader diversity of organohalide-respiring bacteria in the detoxification of 1,2-DCA and 1,1,2-TCA.

1,1,2-trichloroethane↗
DOE OSTI2022

Unconventional Pathways to Carbide Phase Synthesis via Thermal Decomposition of UI 4 (1,4-dioxane) 2

UI4(1,4-dioxane) 2 was subjected to laser-based heating-a method that enables localized, fast heating (T > 2000 °C) and rapid cooling under controlled conditions (scan rate, power, atmosphere, etc.)-to understand its thermal decomposition. A predictive computational thermodynamic technique estimated the decomposition temperature of UI 4 (1,4-dioxane) 2 to uranium (U) metal to be 2236 °C, a temperature achievable under laser irradiation. Dictated by the presence of reactive, gaseous byproducts, the thermal decomposition of UI 4 (1,4-dioxane) 2 under furnace conditions up to 600 °C revealed the formation of UO 2 , UI x , and U(C 1–x O x ) y , while under laser irradiation, UI 4 (1,4-dioxane) 2 decomposed to UO 2 , U(C 1–x O x ) y , UC 2–z O z , and UC. Despite the fast dynamics associated with laser irradiation, the central uranium atom reacted with the thermal decomposition products of the ligand (1,4-dioxane = C 4 H 8 O 2 ) instead of producing pure U metal. In conclusion, the results highlight the potential to co-develop uranium precursors with specific irradiation procedures to advance nuclear materials research by finding new pathways to produce uranium carbide.

36 MATERIALS SCIENCE↗
DOE OSTI2016

DNA-Encoded Library Screening Identifies Benzo[ b ][1,4]oxazepin-4-ones as Highly Potent and Monoselective Receptor Interacting Protein 1 Kinase Inhibitors

The recent discovery of the role of receptor interacting protein 1 (RIP1) kinase in tumor necrosis factor (TNF)- mediated inflammation has led to its emergence as a highly promising target for the treatment of multiple inflammatory diseases. In this work, we screened RIP1 against GSK’s DNA-encoded small-molecule libraries and identified a novel highly potent benzoxazepinone inhibitor series. We demonstrate that this template possesses complete monokinase selectivity for RIP1 plus unique species selectivity for primate versus nonprimate RIP1. We elucidate the conformation of RIP1 bound to this benzoxazepinone inhibitor driving its high kinase selectivity and design specific mutations in murine RIP1 to restore potency to levels similar to primate RIP1. This series differentiates itself from known RIP1 inhibitors in combining high potency and kinase selectivity with good pharmacokinetic profiles in rodents. The favorable developability profile of this benzoxazepinone template, as exemplified by compound 14 (GSK’481), makes it an excellent starting point for further optimization into a RIP1 clinical candidate.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Desolvation Processes in Channel Solvates of Niclosamide

The antiparasitic drug niclosamide (NCL) is notable for its ability to crystallize in multiple 1:1 channel solvate forms, none of which are isostructural. Here, using a combination of time-resolved synchrotron powder X-ray diffraction and thermogravimetry, the process-induced desolvation mechanisms of methanol and acetonitrile solvates are investigated. Structural changes in both solvates follow a complicated molecular-level trajectory characterized by a sudden shift in lattice parameters several degrees below the temperature where the desolvated phase first appears. Model fitting of kinetic data obtained under isothermal heating conditions suggests that the desolvation is rate-limited by the nucleation of the solvent-free product. The desolvation pathways identified in these systems stand in contrast to previous investigations of the NCL channel hydrate, where water loss by diffusion initially yields an anhydrous isomorph that converts to the thermodynamic polymorph at significantly higher temperatures. Taking the view that each solvate lattice is a unique “pre-organized” precursor, a comparison of the pathways from different starting topologies to the same final product provides the opportunity to reevaluate assumptions of how various factors (e.g., solvent binding strength, density) influence solid-state desolvation processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Spatially Resolved Potential and Li-Ion Distributions Reveal Performance-Limiting Regions in Solid-State Batteries

The performance of solid-state electrochemical systems is intimately tied to the potential and lithium distributions across electrolyte–electrode junctions that give rise to interface impedance. Here, we combine two operando methods, Kelvin probe force microscopy (KPFM) and neutron depth profiling (NDP), to identify the rate-limiting interface in operating Si-LiPON-LiCoO 2 solid-state batteries by mapping the contact potential difference (CPD) and the corresponding Li distributions. The contributions from ions, electrons, and interfaces are deconvolved by correlating the CPD profiles with Li-concentration profiles and by comparisons with first-principles-informed modeling. Furthermore, we find that the largest potential drop and variation in the Li concentration occur at the anode–electrolyte interface, with a smaller drop at the cathode–electrolyte interface and a shallow gradient within the bulk electrolyte. Correlating these results with electrochemical impedance spectroscopy following battery cycling at low and high rates confirms a long-standing conjecture linking large potential drops with a rate-limiting interfacial process.

25 ENERGY STORAGE↗