442 research outputs found

    Advanced PPA Reactor and Process Development

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    Design and development of a second generation Plasma Pyrolysis Assembly (PPA) reactor is currently underway as part of NASA s Atmosphere Revitalization Resource Recovery effort. By recovering up to 75% of the hydrogen currently lost as methane in the Sabatier reactor effluent, the PPA helps to minimize life support resupply costs for extended duration missions. To date, second generation PPA development has demonstrated significant technology advancements over the first generation device by doubling the methane processing rate while, at the same time, more than halving the required power. One development area of particular interest to NASA system engineers is fouling of the PPA reactor with carbonaceous products. As a mitigation plan, NASA MSFC has explored the feasibility of using an oxidative plasma based upon metabolic CO2 to regenerate the reactor window and gas inlet ports. The results and implications of this testing are addressed along with the advanced PPA reactor development work

    Phenotypic variation in heteroblastic woody species does not contribute to shade survival

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    Heteroblastic species change their leaf morphology due to changes in light environment. However, growth and biomass allocation pattern do not contribute to their better survival relative to homoblastic congeners in low light. Thus, shade does not select for leaf heteroblasty

    Extracellular Myocardial Volume in Patients With Aortic Stenosis

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    BACKGROUND: Myocardial fibrosis is a key mechanism of left ventricular decompensation in aortic stenosis and can be quantified using cardiovascular magnetic resonance (CMR) measures such as extracellular volume fraction (ECV%). Outcomes following aortic valve intervention may be linked to the presence and extent of myocardial fibrosis. OBJECTIVES: This study sought to determine associations between ECV% and markers of left ventricular decompensation and post-intervention clinical outcomes. METHODS: Patients with severe aortic stenosis underwent CMR, including ECV% quantification using modified Look-Locker inversion recovery-based T1 mapping and late gadolinium enhancement before aortic valve intervention. A central core laboratory quantified CMR parameters. RESULTS: Four-hundred forty patients (age 70 ± 10 years, 59% male) from 10 international centers underwent CMR a median of 15 days (IQR: 4 to 58 days) before aortic valve intervention. ECV% did not vary by scanner manufacturer, magnetic field strength, or T1 mapping sequence (all p > 0.20). ECV% correlated with markers of left ventricular decompensation including left ventricular mass, left atrial volume, New York Heart Association functional class III/IV, late gadolinium enhancement, and lower left ventricular ejection fraction (p < 0.05 for all), the latter 2 associations being independent of all other clinical variables (p = 0.035 and p < 0.001). After a median of 3.8 years (IQR: 2.8 to 4.6 years) of follow-up, 52 patients had died, 14 from adjudicated cardiovascular causes. A progressive increase in all-cause mortality was seen across tertiles of ECV% (17.3, 31.6, and 52.7 deaths per 1,000 patient-years; log-rank test; p = 0.009). Not only was ECV% associated with cardiovascular mortality (p = 0.003), but it was also independently associated with all-cause mortality following adjustment for age, sex, ejection fraction, and late gadolinium enhancement (hazard ratio per percent increase in ECV%: 1.10; 95% confidence interval [1.02 to 1.19]; p = 0.013). CONCLUSIONS: In patients with severe aortic stenosis scheduled for aortic valve intervention, an increased ECV% is a measure of left ventricular decompensation and a powerful independent predictor of mortality

    Intersection between metabolic dysfunction, high fat diet consumption, and brain aging

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    Deleterious neurochemical, structural, and behavioral alterations are a seemingly unavoidable aspect of brain aging. However, the basis for these alterations, as well as the basis for the tremendous variability in regards to the degree to which these aspects are altered in aging individuals, remains to be elucidated. An increasing number of individuals regularly consume a diet high in fat, with high‐fat diet consumption known to be sufficient to promote metabolic dysfunction, although the links between high‐fat diet consumption and aging are only now beginning to be elucidated. In this review we discuss the potential role for age‐related metabolic disturbances serving as an important basis for deleterious perturbations in the aging brain. These data not only have important implications for understanding the basis of brain aging, but also may be important to the development of therapeutic interventions which promote successful brain aging.Fil: Uranga, Romina Maria. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - BahĂ­a Blanca. Instituto de Investigaciones BioquĂ­micas de BahĂ­a Blanca. Universidad Nacional del Sur. Instituto de Investigaciones BioquĂ­micas de BahĂ­a Blanca; ArgentinaFil: Bruce Keller, Annadora J.. State University of Louisiana; Estados UnidosFil: Morrison, Christopher D.. State University of Louisiana; Estados UnidosFil: Fernandez Kim, Sun Ok. State University of Louisiana; Estados UnidosFil: Ebenezer, Philip J.. State University of Louisiana; Estados UnidosFil: Zhang, Le. State University of Louisiana; Estados UnidosFil: Dasuri, Kalavathi. State University of Louisiana; Estados UnidosFil: Keller, Jeffrey N.. State University of Louisiana; Estados Unido

    Coronary Atherosclerotic Plaque Activity and Future Coronary Events

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    This study was funded by a Wellcome Trust Senior Investigator Award (WT103782AIA). Image analysis was supported by National Institutes for Health (R34HL161195 and 1R01HL135557). The content is solely the responsibility of the authors and does not necessarily represent the official views of the Wellcome Trust or the National Institutes of Health. The British Heart Foundation supports DEN (CH/09/002, RG/16/10/32375, RE/18/5/34216), MRD (FS/SCRF/21/32010), NLM (CH/F/21/90010, RG/20/10/34966, RE/18/5/34216) AJM (AA/18/3/34220) and MCW (FS/ICRF/20/26002) and DD (FS/RTF/20/30009, NH/19/1/34595, PG/18/35/33786, PG/15/88/31780, PG/17/64/33205). MRD is the recipient of the Sir Jules Thorn Award for Biomedical Research 2015 (15/JTA). PJS is supported by outstanding investigator award National Institutes for Health (R35HL161195). JK is supported by the National Science Centre 2021/41/B/NZ5/02630. EvB is supported by SINAPSE (www.sinapse.ac.uk). AB is supported by a Clinical Research Training Fellowships (MR/V007254/1). DD is supported by Chest Heart and Stroke Scotland (19/53), Tenovus Scotland (G.18.01), and Friends of Anchor and Grampian NHS-Endowments. The Edinburgh Clinical Research Facilities, Edinburgh Imaging facility and Edinburgh Clinical Trials Unit are supported by the National Health Service Research Scotland through National Health Service Lothian Health Board. The Leeds Clinical Research Facilities are supported by the UK National Institute for Health Research (NIHR) via its Clinical Research Facility programme. The work at Cedars-Sinai Medical Center (the Los Angeles site) was supported in part by the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission. The Chief Investigator and Edinburgh Clinical Trials Unit had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.Peer reviewedPostprin

    Pharyngeal carriage of Neisseria species in the African meningitis belt.

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    OBJECTIVES: Neisseria meningitidis, together with the non-pathogenic Neisseria species (NPNs), are members of the complex microbiota of the human pharynx. This paper investigates the influence of NPNs on the epidemiology of meningococcal infection. METHODS: Neisseria isolates were collected during 18 surveys conducted in six countries in the African meningitis belt between 2010 and 2012 and characterized at the rplF locus to determine species and at the variable region of the fetA antigen gene. Prevalence and risk factors for carriage were analyzed. RESULTS: A total of 4694 isolates of Neisseria were obtained from 46,034 pharyngeal swabs, a carriage prevalence of 10.2% (95% CI, 9.8-10.5). Five Neisseria species were identified, the most prevalent NPN being Neisseria lactamica. Six hundred and thirty-six combinations of rplF/fetA_VR alleles were identified, each defined as a Neisseria strain type. There was an inverse relationship between carriage of N. meningitidis and of NPNs by age group, gender and season, whereas carriage of both N. meningitidis and NPNs was negatively associated with a recent history of meningococcal vaccination. CONCLUSION: Variations in the prevalence of NPNs by time, place and genetic type may contribute to the particular epidemiology of meningococcal disease in the African meningitis belt.MenAfriCar was funded by the Wellcome Trust (086546/Z/08/Z) and the Bill and Melinda Gates Foundation (51251). Kanny Diallo holds a Wellcome Trust Training Fellowship in Public Health and Tropical Medicine.This is the final version of the article. It first appeared from Elsevier via https://doi.org/10.1016/j.jinf.2016.03.01
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