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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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421 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Association of Diet and Antimicrobial Resistance in Healthy U.S. Adults

Antimicrobial resistance (AMR) represents a significant source of morbidity and mortality worldwide, with expectations that AMR-associated consequences will continue to worsen throughout the coming decades. Since resistance to antibiotics is encoded in the microbiome, interventions aimed at altering the taxonomic composition of the gut might allow us to prophylactically engineer microbiomes that harbor fewer antibiotic resistant genes (ARGs). Diet is one method of intervention, and yet little is known about the association between diet and antimicrobial resistance. To address this knowledge gap, we examined diet using the food frequency questionnaire (FFQ; habitual diet) and 24-h dietary recalls (Automated Self-Administered 24-h [ASA24 ® ] tool) coupled with an analysis of the microbiome using shotgun metagenome sequencing in 290 healthy adult participants of the United States Department of Agriculture (USDA) Nutritional Phenotyping Study. We found that aminoglycosides were the most abundant and prevalent mechanism of AMR in these healthy adults and that aminoglycoside-O-phosphotransferases (aph3-dprime) correlated negatively with total calories and soluble fiber intake. Individuals in the lowest quartile of ARGs (low-ARG) consumed significantly more fiber in their diets than medium- and high-ARG individuals, which was concomitant with increased abundances of obligate anaerobes, especially from the family Clostridiaceae, in their gut microbiota. Finally, we applied machine learning to examine 387 dietary, physiological, and lifestyle features for associations with antimicrobial resistance, finding that increased phylogenetic diversity of diet was associated with low-ARG individuals. These data suggest diet may be a potential method for reducing the burden of AMR.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Proteomes reveal metabolic capabilities of Yarrowia lipolytica for biological upcycling of polyethylene into high-value chemicals

ABSTRACT Polyolefins derived from plastic wastes are recalcitrant for biological upcycling. However, chemical depolymerization of polyolefins can generate depolymerized plastic (DP) oil, comprising of a complex mixture of saturated, unsaturated, even, and odd hydrocarbons suitable for biological conversion. While DP oil contains a rich carbon and energy source, it is inhibitory to cells. Understanding and harnessing robust metabolic capabilities of microorganisms to upcycle the hydrocarbons in DP oil, both naturally and unnaturally occurring, into high-value chemicals are limited. Here, we discovered that an oleaginous yeast, Yarrowia lipolytica, undergoing short-term adaptation to DP oil robustly utilized a wide range of hydrocarbons for cell growth and production of citric acid and neutral lipids. When growing on hydrocarbons, Y. lipolytica partitioned into planktonic and oil-bound cells with each exhibiting distinct proteomes and amino acid distributions invested in establishing these proteomes. Significant proteome reallocation toward energy and lipid metabolism, belonging to 2 of the 23 Eukaryotic Orthologous Groups classes C and I, enabled robust growth of Y. lipolytica on hydrocarbons, with n-hexadecane as the preferential substrate. This investment was even higher for growth on DP oil where classes C and I were ranked one and two, respectively, and many associated proteins and pathways were expressed and upregulated including the hydrocarbon degradation pathway, Krebs cycle, glyoxylate shunt and, unexpectedly, propionate metabolism. However, a reduction in proteome allocation for protein biosynthesis, at the expense of the observed increase toward energy and lipid metabolisms, might have caused the inhibitory effect of DP oil on cell growth. IMPORTANCE Sustainable processes for biological upcycling of plastic wastes in a circular bioeconomy are needed to promote decarbonization and reduce environmental pollution due to increased plastic consumption, incineration, and landfill storage. Strain characterization and proteomic analysis revealed the robust metabolic capabilities of Yarrowia lipolytica to upcycle polyethylene into high-value chemicals. Significant proteome reallocation toward energy and lipid metabolisms was required for robust growth on hydrocarbons with n-hexadecane as the preferential substrate. However, an apparent over-investment in these same categories to utilize complex depolymerized plastic (DP) oil came at the expense of protein biosynthesis, limiting cell growth. Taken together, this study elucidates how Y. lipolytica activates its metabolism to utilize DP oil and establishes Y. lipolytica as a promising host for the upcycling of plastic wastes.

1-alkenes↗
DOE OSTI2021

Dehydrogenation of 1-Phenylethanol Catalyzed by Nickel(II)diphosphine Complexes

Catalytic efficacy of the nickel(II)-diphosphine systems in the dehydrogenation of 1-phenylethanol to acetophenone under acceptorless conditions was investigated. Steric and electronic factors of the phosphine ligands were found to play an important role in the catalysis, while the nature of the base used and the reaction conditions, viz. time, temperature, and stoichiometry, have also shown major influence. Based on the preliminary analysis, a homogeneous pathway, perhaps involving nickel hydride species, was proposed. Due to the gradual disintegration of the catalytic species, deterioration of catalytic activity was observed resulting into low to moderate conversions. Among the series of catalysts examined, the highest conversion of 52% was exhibited by the catalyst C4, dichloro(1,2-bis(diphenylphosphino)ethane)nickel(II) (5 mol%), when loaded with 50 mol% of sodium ethoxide in toluene at 120 °C.

1,2 bis(alkyl/arylphosphino) alkane. homogeneous c↗
DOE OSTI2021

Outcomes of OpenMP Hackathon: OpenMP Application Experiences with the Offloading Model (Part II)

This paper reports on experiences gained and practices adopted when using the latest features of OpenMP to port a variety of HPC applications and mini-apps based on different computational motifs (BerkeleyGW, WDMApp/XGC, GAMESS, GESTS, and GridMini) to accelerator-based, leadership-class, high-performance supercomputer systems at the Department of Energy. As recent enhancements to OpenMP become available in implementations, there is a need to share the results of experimentation with them in order to better understand their behavior in practice, to identify pitfalls, and to learn how they can be effectively deployed in scientific codes. Additionally, we identify best practices from these experiences that we can share with the rest of the OpenMP community.

Chapman, Barbara↗
DOE OSTI2021

Outcomes of OpenMP Hackathon: OpenMP Application Experiences with the Offloading Model (Part I)

This paper reports on experiences gained and practices adopted when using the latest features of OpenMP to port a variety of HPC applications and mini-apps based on different computational motifs (BerkeleyGW, WDMApp/XGC, GAMESS, GESTS, and GridMini) to accelerator-based, leadership-class, high-performance supercomputer systems at the Department of Energy. As recent enhancements to OpenMP become available in implementations, there is a need to share the results of experimentation with them in order to better understand their behavior in practice, to identify pitfalls, and to learn how they can be effectively deployed in scientific codes. Additionally, we identify best practices from these experiences that we can share with the rest of the OpenMP community.

Chapman, Barbara↗