Publications by authors named "David Stahl"

Introduction: Lack of social support negatively impacts medical trainees' wellness. Programmes to educate medical trainees and their support persons (SPs) have been developed to improve resident wellness, but implementation of these programmes at other institutions remains unclear. We aimed to demonstrate the feasibility of implementing the Family Anesthesia Experience (FAX) programme across multiple institutions and to assess the programme's utility.

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This study evaluates the H2AX/γ-H2AX expression in soft tissue sarcomas (STS), its implications for biological behavior and immune environment, and its potential as a prognostic biomarker. RNA-Seq data from 237 STS were obtained from The Cancer Genome Atlas project. Patients were stratified by H2AX mRNA expression using a survival-associated cutoff.

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Resource partitioning is central to the incredible productivity of microbial communities, including gigatons in annual methane emissions through syntrophic interactions. Previous work revealed how a sulfate reducer (Desulfovibrio vulgaris, Dv) and a methanogen (Methanococcus maripaludis, Mm) underwent evolutionary diversification in a planktonic context, improving stability, cooperativity, and productivity within 300-1000 generations. Here, we show that mutations in just 15 Dv and 7 Mm genes within a minimal assemblage of this evolved community gave rise to co-existing ecotypes that were spatially enriched within a few days of culturing in a fluidized bed reactor.

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Climate changes significantly impact greenhouse gas emissions from wetland soil. Specifically, wetland soil may be exposed to oxygen (O) during droughts, or to sulfate (SO) as a result of sea level rise. How these stressors - separately and together - impact microbial food webs driving carbon cycling in the wetlands is still not understood.

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Cobalamin (B), an essential nutrient and growth cofactor for many living organisms on Earth, can be fully synthesized only by selected prokaryotes in nature. Therefore, microbial communities related to B biosynthesis could serve as an example subsystem to disentangle the underlying ecological mechanisms balancing the function and taxonomic make-up of complex functional assemblages. By anchoring microbial traits potentially involved in B biosynthesis, we depict the biogeographic patterns of B biosynthesis genes and the taxa harboring them in the global ocean, despite the limitations of detecting de novo B synthesizers via metagenomes alone.

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Performance evaluation of in situ bioremediation processes in the field is difficult due to uncertainty created by matrix and contaminant heterogeneity, inaccessibility to direct observation, expense of sampling, and limitations of some measurements. The goal of this research was to develop a strategy for evaluating in situ bioremediation of light nonaqueous-phase liquid (LNAPL) contamination and demonstrating the occurrence of bioenhanced LNAPL dissolution by: (1) integrating a suite of analyses into a rational evaluation strategy; and (2) demonstrating the strategy's application in intermediate-scale flow-cell (ISFC) experiments simulating an aquifer contaminated with a pool of LNAPL (naphthalene dissolved in dodecane). Two ISFCs were operated to evaluate how the monitored parameters changed between a "no bioremediation" scenario and an "intrinsic in situ bioremediation" scenario.

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Castellaniella species have been isolated from a variety of mixed-waste environments including the nitrate and multiple metal-contaminated subsurface at the Oak Ridge Reservation (ORR). Previous studies examining microbial community composition and nitrate removal at ORR during biostimulation efforts reported increased abundances of members of the Castellaniella genus concurrent with increased denitrification rates. Thus, we asked how genomic and abiotic factors control the Castellaniella biogeography at the site to understand how these factors may influence nitrate transformation in an anthropogenically impacted setting.

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The sources and sinks of nitrous oxide, as control emissions to the atmosphere, are generally poorly constrained for most environmental systems. Initial depth-resolved analysis of nitrous oxide flux from observation wells and the proximal surface within a nitrate contaminated aquifer system revealed high subsurface production but little escape from the surface. To better understand the environmental controls of production and emission at this site, we used a combination of isotopic, geochemical, and molecular analyses to show that chemodenitrification and bacterial denitrification are major sources of nitrous oxide in this subsurface, where low DO, low pH, and high nitrate are correlated with significant nitrous oxide production.

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Ammonia-oxidizing archaea (AOA) are among the most ubiquitous and abundant archaea on Earth, widely distributed in marine, terrestrial, and geothermal ecosystems. However, the genomic diversity, biogeography, and evolutionary process of AOA populations in subsurface environments are vastly understudied compared to those in marine and soil systems. Here, we report a novel AOA order Candidatus (Ca.

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Ammonia-oxidizing microorganisms (AOM) contribute to one of the largest nitrogen fluxes in the global nitrogen budget. Four distinct lineages of AOM: ammonia-oxidizing archaea (AOA), beta- and gamma-proteobacterial ammonia-oxidizing bacteria (β-AOB and γ-AOB) and complete ammonia oxidizers (comammox), are thought to compete for ammonia as their primary nitrogen substrate. In addition, many AOM species can utilize urea as an alternative energy and nitrogen source through hydrolysis to ammonia.

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Community assembly describes how different ecological processes shape microbial community composition and structure. How environmental factors impact community assembly remains elusive. Here we sampled microbial communities and >200 biogeochemical variables in groundwater at the Oak Ridge Field Research Center, a former nuclear waste disposal site, and developed a theoretical framework to conceptualize the relationships between community assembly processes and environmental stresses.

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Background: No study has contextualized the excess mortality attributable to racial and ethnic disparities in surgical outcomes. Further, not much effort has been made to quantify the effort needed to eliminate these disparities.

Objective: We examined the current trends in mortality attributable to racial or ethnic disparities in the US postsurgical population.

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Wetlands are crucial nodes in the carbon cycle, emitting approximately 20% of global CH while also sequestering 20%-30% of all soil carbon. Both greenhouse gas fluxes and carbon storage are driven by microbial communities in wetland soils. However, these key players are often overlooked or overly simplified in current global climate models.

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Background:  At the onset of the coronavirus disease 2019 (COVID-19) pandemic, anesthesiology residency programs were impacted differently due to various factors such as the local severity of COVID-19, exposure to patient suffering, and inability to complete rotations. We sought to investigate the impact of local-level pandemic severity on the well-being of anesthesiology residents.

Methods:  This multi-site study surveyed postgraduate year two residents from 15 United States (US) anesthesiology programs using the Perceived Stress Scale, Mini-Z, Patient Health Questionnaire-9,WHO-5 Well-Being Index,and the Multidimensional Scale of Perceived Social Support before the pandemic (baseline survey) and during the first COVID-19 surge (post survey).

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Complex interactions exist among microorganisms in a community to carry out ecological processes and adapt to changing environments. Here, we constructed a quad-culture consisting of a cellulolytic bacterium (Ruminiclostridium cellulolyticum), a hydrogenotrophic methanogen (Methanospirillum hungatei), an acetoclastic methanogen (Methanosaeta concilii), and a sulfate-reducing bacterium (Desulfovibrio vulgaris). The four microorganisms in the quad-culture cooperated via cross-feeding to produce methane using cellulose as the only carbon source and electron donor.

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Consideration for blood products replacement in postpartum hemorrhage should be given when blood loss exceeds 1.5 L or when an estimated 25% of blood has been lost. In cases of massive hemorrhage, standardized transfusion protocols have been shown to improve maternal morbidity and mortality.

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Background: Several health authorities recommend a third (booster) vaccination to protect patients with rheumatic and musculoskeletal diseases from severe COVID-19. Methotrexate has been shown to reduce the efficacy of the first and second dose of SARS-CoV-2 mRNA vaccines. So far, it remains unknown how concomitant methotrexate affects the efficacy of a COVID-19 booster vaccination.

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Bacillus cereus strain CPT56D-587-MTF (CPTF) was isolated from the highly contaminated Oak Ridge Reservation (ORR) subsurface. This site is contaminated with high levels of nitric acid and multiple heavy metals. Amplicon sequencing of the 16S rRNA genes (V4 region) in sediment from this area revealed an amplicon sequence variant (ASV) with 100% identity to the CPTF 16S rRNA sequence.

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A betaproteobacterial chemolithotrophic ammonia-oxidizing bacterium designated APG5 was isolated from supralittoral sand of the Edmonds City Beach, WA, USA. Growth was observed at 10-35 °C (optimum, 30 °C), pH 5-9 (optimum, pH 8) and ammonia concentrations as high as 100 mM (optimum, 1-30 mM NHCl). The strain grows optimally in a freshwater medium but tolerates up to 400 mM NaCl.

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Objective: SLE is an autoimmune disease with a complex pathogenesis. T-cell infiltration into organs contributes to inflammation and organ damage in SLE. Recently, G-protein signalling modulator 2 (GPSM2) has been shown to be implicated in T-cell migration.

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Recently, immunotherapeutic approaches have become a feasible option for a subset of pediatric cancer patients. Low MHC class I expression hampers the use of immunotherapies relying on antigen presentation. A well-established stemness score (mRNAsi) was determined using the bulk transcriptomes of 1134 pediatric small round blue cell tumors.

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