80 research outputs found
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Ultra-clean Fischer-Tropsch (F-T) Fuels Production and Demonstration Project
The objective of the DOE-NETL Fischer-Tropsch (F-T) Production and Demonstration Program was to produce and evaluate F-T fuel derived from domestic natural gas. The project had two primary phases: (1) fuel production of ultra-clean diesel transportation fuels from domestic fossil resources; and (2) demonstration and performance testing of these fuels in engines. The project also included a well-to-wheels economic analysis and a feasibility study of small-footprint F-T plants (SFPs) for remote locations such as rural Alaska. During the fuel production phase, ICRC partnered and cost-shared with Syntroleum Corporation to complete the mechanical design, construction, and operation of a modular SFP that converts natural gas, via F-T and hydro-processing reactions, into hydrogensaturated diesel fuel. Construction of the Tulsa, Oklahoma plant started in August 2002 and culminated in the production of over 100,000 gallons of F-T diesel fuel (S-2) through 2004, specifically for this project. That fuel formed the basis of extensive demonstrations and evaluations that followed. The ultra-clean F-T fuels produced had virtually no sulfur (less than 1 ppm) and were of the highest quality in terms of ignition quality, saturation content, backend volatility, etc. Lubricity concerns were investigated to verify that commercially available lubricity additive treatment would be adequate to protect fuel injection system components. In the fuel demonstration and testing phase, two separate bus fleets were utilized. The Washington DC Metropolitan Area Transit Authority (WMATA) and Denali National Park bus fleets were used because they represented nearly opposite ends of several spectra, including: climate, topography, engine load factor, mean distance between stops, and composition of normally used conventional diesel fuel. Fuel evaluations in addition to bus fleet demonstrations included: bus fleet emission measurements; F-T fuel cold weather performance; controlled engine dynamometer lab evaluation; cold-start test-cell evaluations; overall feasibility, economics, and efficiency of SFP fuel production; and an economic analysis. Two unexpected issues that arose during the project were further studied and resolved: variations in NOx emissions were accounted for and fuel-injection nozzle fouling issues were traced to the non-combustible (ash) content of the engine oil, not the F-T fuel. The F-T fuel domestically produced and evaluated in this effort appears to be a good replacement candidate for petroleum-based transportation fuels. However, in order for domestic F-T fuels to become a viable cost-comparable alternative to petroleum fuels, the F-T fuels will need to be produced from abundant U.S. domestic resources such as coal and biomass, rather than stranded natural gas
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FISCHER-TROPSCH FUELS PRODUCTION AND DEMONSTRATION PROJECT
This project has two primary purposes: (1) Build a small-footprint (SFP) fuel production plant to prove the feasibility of this relatively transportable technology on an intermediate scale (i.e. between laboratory-bench and commercial capacity) and produce as much as 150,000 gallons of hydrogen-saturated Fischer-Tropsch (FT) diesel fuel; and (2) Use the virtually sulfur-free fuel produced to demonstrate (over a period of at least six months) that it can not only be used in existing diesel engines, but that it also can enable significantly increased effectiveness and life of the next-generation exhaust-after-treatment emission control systems that are currently under development and that will be required for future diesel engines. Furthermore, a well-to-wheels economic analysis will be performed to characterize the overall costs and benefits that would be associated with the actual commercial production, distribution and use of such FT diesel fuel made by the process under consideration, from the currently underutilized (or entirely un-used) energy resources targeted, primarily natural gas that is stranded, sub-quality, off-shore, etc. During the first year of the project, which is the subject of this report, there have been two significant areas of progress: (1) Most of the preparatory work required to build the SFP fuel-production plant has been completed, and (2) Relationships have been established, and necessary project coordination has been started, with the half dozen project-partner organizations that will have a role in the fuel demonstration and evaluation phase of the project. Additional project tasks directly related to the State of Alaska have also been added to the project. These include: A study of underutilized potential Alaska energy resources that could contribute to domestic diesel and distillate fuel production by providing input energy for future commercial-size SFP fuel production plants; Demonstration of the use of the product fuel in a heavy-duty diesel vehicle during the Alaska winter; a comparative study of the cold-starting characteristics of FT and conventional diesel fuel; and demonstration of the use of the fuel to generate electricity for rural Alaskan villages using both a diesel generator set, and a reformer-equipped fuel cell
PROPHETIC EU: Prospective identification of pneumonia in hospitalized patients in the intensive care unit in European and United States cohorts
BACKGROUND: The prospective identification of patients at high risk for hospital-acquired/ventilator-associated bacterial pneumonia may improve clinical trial feasibility and foster antibacterial development. In a prior study conducted in the United States, clinical criteria were used to prospectively identify these patients; however, these criteria have not been applied in a European population.
METHODS: Adults considered high risk for pneumonia (treatment with ventilation or high levels of supplemental oxygen) in the intensive care units of 7 European hospitals were prospectively enrolled from June 12 to December 27, 2017. We estimated the proportion of high-risk patients developing pneumonia according to US Food and Drug Administration guidance and a subset potentially eligible for antibacterial trial enrollment. We compared patient characteristics, treatment exposures, and pneumonia incidence in a European cohort and a previously described US cohort.
RESULTS: Of 888 high-risk patients, 211/888 (24%) were treated for possible pneumonia, and 150/888 (17%) met the Food and Drug Administration definition for hospital-acquired/ventilator-associated bacterial pneumonia. A higher proportion of European patients treated for possible pneumonia met the pneumonia definition (150/211 [71%] vs 537/1464 [37%];
CONCLUSIONS: Clinical criteria prospectively identified high-risk patients with high rates of pneumonia in the European cohort. Despite higher rates of established risk factors and incident pneumonia, European patients were significantly less likely to receive antibiotics for possible pneumonia than US patients. Different treatment practices may contribute to lower rates of antibacterial trial enrollment in the United States
Blinded and unblinded hypohydration similarly impair cycling time trial performance in the heat in trained cyclists
Knowledge of hydration status may contribute to hypohydration-induced exercise performance decrements, therefore, this study compared blinded and unblinded hypohydration on cycling performance. Fourteen trained, non-heat acclimated cyclists (age 25 ± 5 y; V̇O2peak 63.3 ± 4.7 mL∙kg-1∙min-1; cycling experience 6 ± 3 y) were pair-matched to blinded (B) or unblinded (UB) groups. After familiarisation, subjects completed euhydrated (B-EUH; UB-EUH) and hypohydrated (B-HYP; UB-HYP) trials in the heat (31˚C); 120 min cycling preload (50% Wpeak) and a time trial (~15 min). During the preload of all trials, 0.2 mL water∙kg body mass-1 was ingested every 10 min, with additional water provided during EUH trials to match sweat losses. To blind the B group, a nasogastric tube was inserted in both trials and used to provide water in B-EUH. The preload induced similar ( P=0.895) changes in body mass between groups (B-EUH -0.6 ± 0.5%; B-HYP -3.0 ± 0.5%; UB-EUH -0.5 ± 0.3%; UB-HYP -3.0 ± 0.3%). All variables responded similarly between B and UB groups ( P≥0.558), except thirst ( P=0.004). Changes typical of hypohydration (increased heart rate, RPE, gastrointestinal temperature, serum osmolality and thirst, decreased plasma volume; P≤0.017) were apparent in HYP by 120 min. Time trial performance was similar between groups ( P=0.710) and slower ( P≤0.013) with HYP for B (B-EUH 903 ± 89 s; B-HYP 1008 ± 121 s; -11.4%) and UB (UB-EUH 874 ± 108 s; UB-HYP 967 ± 170 s; -10.1%). Hypohydration of ~3% body mass impairs time trial performance in the heat, regardless of knowledge of hydration status
Airway inflammatory markers in individuals with cystic fibrosis and non-cystic fibrosis bronchiectasis.
Bronchiectasis is an airway disease characterized by thickening of the bronchial wall, chronic inflammation , and destruction of affected bronchi. Underlying etiologies include severe pulmonary infection and cystic fibrosis (CF); however, in a substantial number of patients with non-CF-related bronchiectasis (NCFB), no cause is found. The increasing armamentarium of therapies now available to combat disease in CF is in stark contrast to the limited tools employed in NCFB. Our study aimed to evaluate similarities and differences in airway inflammatory markers in patients with NCFB and CF, and to suggest potential common treatment options. The results of this study show that NCFB bronchoalveolar lavage fluid samples possessed significantly increased NE activity and elevated levels of matrix metalloproteinases 2 (MMP-2) and MMP-9 compared to healthy controls (P \u3c 0.01); however, the levels detected were lower than in CF (P \u3c 0.01). Interleukin-8 (IL-8) concentrations were significantly elevated in NCFB and CF compared to controls (P \u3c 0.05), but in contrast, negligible levels of IL-18 were detected in both NCFB and CF. Analogous concentrations of IL-10 and IL-4 measured in NCFB and CF were statistically elevated above the healthy control values (P \u3c 0.05 and P \u3c 0.01, respectively). These results indicate high levels of important proinflammatory markers in both NCFB and CF and support the use of appropriate anti-inflammatory therapies already employed in the treatment of CF bronchiectasis in NCFB
PROPHETIC: Prospective Identification of Pneumonia in Hospitalized Patients in the Intensive Care Unit
BACKGROUND: Pneumonia is the leading infection-related cause of death. Using simple clinical criteria and contemporary epidemiology to identify patients at high risk of nosocomial pneumonia should enhance prevention efforts and facilitate development of new treatments in clinical trials.
RESEARCH QUESTION: What are the clinical criteria and contemporary epidemiology trends helpful in identifying patients at high risk of nosocomial pneumonia?
STUDY DESIGN AND METHODS: Within the intensive care units of 28 United States hospitals, we conducted a prospective cohort study among adults hospitalized more than 48 hours and considered high risk for pneumonia (defined as treatment with invasive or noninvasive ventilatory support or high levels of supplemental oxygen). We estimated the proportion of high-risk patients developing nosocomial pneumonia. Using multivariable logistic regression, we identified patient characteristics and treatment exposures associated with increased risk of pneumonia development during the intensive care unit admission.
RESULTS: Between February 6, 2016 and October 7, 2016, 4613 high-risk patients were enrolled. Among 1464/4613 (32%) high-risk patients treated for possible nosocomial pneumonia, 537/1464 (37%) met the study pneumonia definition. Among high-risk patients, a multivariable logistic model was developed to identify key patient characteristics and treatment exposures associated with increased risk of nosocomial pneumonia development (c-statistic 0.709, 95% confidence interval 0.686 to 0.731). Key factors associated with increased odds of nosocomial pneumonia included an admission diagnosis of trauma or cerebrovascular accident, receipt of enteral nutrition, documented aspiration risk, and receipt of systemic antibacterials within the preceding 90 days.
INTERPRETATION: Treatment for nosocomial pneumonia is common among intensive care unit patients receiving high levels of respiratory support, yet more than half of patients treated do not fulfill standard diagnostic criteria for pneumonia. Application of simple clinical criteria may improve the feasibility of clinical trials of pneumonia prevention and treatment by facilitating prospective identification of patients at highest risk
PROPHETIC EU: Prospective Identification of Pneumonia in Hospitalized Patients in the Intensive Care Unit in European and United States Cohorts
Background The prospective identification of patients at high risk for hospital-acquired/ventilator-associated bacterial pneumonia may improve clinical trial feasibility and foster antibacterial development. In a prior study conducted in the United States, clinical criteria were used to prospectively identify these patients; however, these criteria have not been applied in a European population. Methods Adults considered high risk for pneumonia (treatment with ventilation or high levels of supplemental oxygen) in the intensive care units of 7 European hospitals were prospectively enrolled from June 12 to December 27, 2017. We estimated the proportion of high-risk patients developing pneumonia according to US Food and Drug Administration guidance and a subset potentially eligible for antibacterial trial enrollment. We compared patient characteristics, treatment exposures, and pneumonia incidence in a European cohort and a previously described US cohort. Results Of 888 high-risk patients, 211/888 (24%) were treated for possible pneumonia, and 150/888 (17%) met the Food and Drug Administration definition for hospital-acquired/ventilator-associated bacterial pneumonia. A higher proportion of European patients treated for possible pneumonia met the pneumonia definition (150/211 [71%] vs 537/1464 [37%]; P < .001). Among patients developing pneumonia, a higher proportion of European patients met antibacterial trial eligibility criteria (124/150 [83%] vs 371/537 [69%]; P < .001). Conclusions Clinical criteria prospectively identified high-risk patients with high rates of pneumonia in the European cohort. Despite higher rates of established risk factors and incident pneumonia, European patients were significantly less likely to receive antibiotics for possible pneumonia than US patients. Different treatment practices may contribute to lower rates of antibacterial trial enrollment in the United States
Probing the charging mechanisms of carbon nanomaterial polyelectrolytes
Chemical charging of single-walled carbon nanotubes (SWCNTs) and graphenes to generate soluble salts shows great promise as a processing route for electronic applications, but raises fundamental questions. The reduction potentials of highly-charged nanocarbon polyelectrolyte ions were investigated by considering their chemical reactivity towards metal salts/complexes in forming metal nanoparticles. The redox activity, degree of functionalisation and charge utilisation were quantified via the relative metal nanoparticle content, established using thermogravimetric analysis (TGA), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and X-ray photoelectron spectroscopy (XPS). The fundamental relationship between the intrinsic nanocarbon electronic density of states and Coulombic effects during charging is highlighted as an important area for future research
Improved diagnosis of SARS-CoV-2 by using nucleoprotein and spike protein fragment 2 in quantitative dual ELISA tests
The novel coronavirus, severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), is the
causative agent of the 2020 worldwide coronavirus pandemic. Antibody testing is useful for
diagnosing historic infections of a disease in a population. These tests are also a helpful
epidemiological tool for predicting how the virus spreads in a community, relating antibody
levels to immunity and for assessing herd immunity. In the present study, SARS-CoV-2 viral proteins were recombinantly produced and used to analyse serum from individuals previously
exposed, or not, to SARS-CoV-2. The nucleocapsid (Npro) and spike subunit 2 (S2Frag) proteins
were identified as highly immunogenic, although responses to the former were generally greater.
These two proteins were used to develop two quantitative enzyme-linked immunosorbent assays
(ELISAs) that when used in combination resulted in a highly reliable diagnostic test. Npro and
S2Frag-ELISAs could detect at least 10% more true positive coronavirus disease-2019 (COVID-19) cases than the commercially available ARCHITECT test (Abbott). Moreover, our quantitative ELISAs also show that specific antibodies to SARS-CoV-2 proteins tend to wane rapidly even
in patients who had developed severe disease. As antibody tests complement COVID-19 diagnosis and determine population-level surveillance during this pandemic, the alternative diagnostic
we present in this study could play a role in controlling the spread of the virus
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
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