79 research outputs found
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Impact of microbial growth on water flow and solute transport in unsaturated porous media
A novel analytical method was developed that permitted real-time, noninvasive measurements of microbial growth and associated changes in hydrodynamic properties in porous media under unsaturated flowing conditions. Salicylate-induced, lux gene-based bioluminescence was used to quantify the temporal and spatial development of colonization over a 7-day time course. Water contents were determined daily by measuring light transmission through the system. Hydraulic flow paths were determined daily by pulsing a bromophenol blue dye solution through the colonized region of the sand. Bacterial growth and accumulation had a significant impact on the hydraulic properties of the porous media. Microbial colonization caused localized drying within the colonized zone, with decreases in saturation approaching 50% of antecedent values, and a 25% lowering of the capillary fringe height. Flow was retarded within the colonized zone and diverted around it concurrent with the expansion of the colonized zone between days 3 and 6. The location of horizontal dispersion corresponded with the cell densities of 1â3 Ă 10âč cells gâ»Âč dry sand. The apparent solute velocity through the colonized region was reduced from 0.41 cm minâ»Âč (RÂČ = 0.99) to 0.25 cm minâ»Âč (RÂČ = 0.99) by the sixth day of the experiment, associated with population densities that would occupy approximately 7% of the available pore space within the colonized region. Changes in the extent of colonization occurred over the course of the experiment, including upward migration against flow. The distribution of cells was not determined by water flow alone, but rather by a dynamic interaction between water flow and microbial growth. This experimental system provides rich data sets for the testing of conceptualizations expressed through numerical modeling.Keywords: Bacteria in the subsurface, Vadose zone, Bacteria in porous medi
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Borehole Data Package for One CY 2005 CERCLA Well 699-S20-E10, 300-FF-5 Operable Unit, Hanford Site, Washington
This report supplies the information obtained during drilling, characterization, and installation of the new groundwater monitoring well. This document also provides a compilation of hydrogeologic and well construction information obtained during drilling, well development, and sample collection/analysis activities
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Noninvasive Quantitative Measurement of Bacterial Growth in Porous Media under Unsaturated-Flow Conditions
Glucose-dependent growth of the luxCDABE reporter bacterium Pseudomonas fluorescens HK44 was monitored noninvasively in quartz sand under unsaturated-flow conditions within a 45- by 56- by 1-cm two-dimensional light transmission chamber. The spatial and temporal development of growth were mapped daily over 7 days by quantifying salicylate-induced bioluminescence. A nonlinear model relating the rate of increase in light emission after salicylate exposure to microbial density successfully predicted growth over 4 orders of magnitude (rÂČ = 0.95). Total model-predicted growth agreed with growth calculated from the mass balance of the system by using previously established growth parameters of HK44 (predicted, 1.2 Ă 10ÂčÂČ cells; calculated, 1.7 Ă 10ÂčÂČ cells). Colonization expanded in all directions from the inoculation region, including upward migration against the liquid flow. Both the daily rate of expansion of the colonized zone and the population density of the first day's growth in each newly colonized region remained relatively constant throughout the experiment. Nonetheless, substantial growth continued to occur on subsequent days in the older regions of the colonized zone. The proportion of daily potential growth that remained within the chamber declined progressively between days 2 and 7 (from 97 to 13%). A densely populated, anoxic region developed in the interior of the colonized zone even though the sand was unsaturated and fresh growth medium continued to flow through the colonized zone. These data illustrate the potential of a light transmission chamber, bioluminescent bacteria, and sensitive digital camera technology to noninvasively study real-time hydrology-microbiology interactions associated with unsaturated flow in porous media
European regulatory agenices should employ full time statisticians
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Association of chronic obstructive pulmonary disease with morbidity and mortality in patients with peripheral artery disease: insights from the EUCLID trial
Background: Patients with chronic obstructive pulmonary disease (COPD) are at increased risk of developing lower extremity peripheral artery disease (PAD) and suffering PAD-related morbidity and mortality. However, the effect and burden of COPD on patients with PAD is less well defined. This post hoc analysis from EUCLID aimed to analyze the risk of major adverse cardiovascular events (MACE) and major adverse limb events (MALE) in patients with PAD and concomitant COPD compared with those without COPD, and to describe the adverse events specific to patients with COPD. Methods: EUCLID randomized 13,885 patients with symptomatic PAD to monotherapy with either ticagrelor or clopidogrel for the prevention of MACE. In this analysis, MACE, MALE, mortality, and adverse events were compared between groups with and without COPD using unadjusted and adjusted Cox proportional hazards model. Results: Of the 13,883 patients with COPD status available at baseline, 11% (n=1538) had COPD. Patients with COPD had a higher risk of MACE (6.02 vs 4.29 events/100 patient-years; p< 0.001) due to a significantly higher risk of myocardial infarction (MI) (3.55 vs 1.85 events/100 patient-years; p< 0.001) when compared with patients without COPD. These risks persisted after adjustment (MACE: adjusted hazard ratio (aHR) 1.30, 95% confidence interval [CI] 1.11â 1.52; p< 0.001; MI: aHR 1.45, 95% CI 1.18â 1.77; p< 0.001). However, patients with COPD did not have an increased risk of MALE or major bleeding. Patients with COPD were more frequently hospitalized for dyspnea and pneumonia (2.66 vs 0.9 events/100 patient-years; aHR 2.77, 95% CI 2.12â 3.63; p< 0.001) and more frequently discontinued study drug prematurely (19.36 vs 12.54 events/100 patient-years; p< 0.001; aHR 1.34, 95% CI 1.22â 1.47; p< 0.001). Conclusion: In patients with comorbid PAD and COPD, the risks of MACE, respiratory-related adverse events, and premature study drug discontinuation were higher when compared with patients without COPD. Registration: ClinicalTrials.gov: NCT01732822
Dialysis Initiation in Patients With Chronic Coronary Disease and Advanced Chronic Kidney Disease in ISCHEMIA-CKD
Background In participants with concomitant chronic coronary disease and advanced chronic kidney disease (CKD), the effect of treatment strategies on the timing of dialysis initiation is not well characterized. Methods and Results In ISCHEMIA-CKD (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches-Chronic Kidney Disease), 777 participants with advanced CKD and moderate or severe ischemia were randomized to either an initial invasive or conservative management strategy. Herein, we compare the proportion of randomized participants with non-dialysis-requiring CKD at baseline (n=362) who initiated dialysis and compare the time to dialysis initiation between invasive versus conservative management arms. Using multivariable Cox regression analysis, we also sought to identify the effect of invasive versus conservative chronic coronary disease management strategies on dialysis initiation. At a median follow-up of 23 months (25th-75th interquartile range, 14-32 months), dialysis was initiated in 18.9% of participants (36/190) in the invasive strategy and 16.9% of participants (29/172) in the conservative strategy (P=0.22). The median time to dialysis initiation was 6.0 months (interquartile range, 3.0-16.0 months) in the invasive group and 18.2 months (interquartile range, 12.2-25.0 months) in the conservative group (P=0.004), with no difference in procedural acute kidney injury rates between the groups (7.8% versus 5.4%; P=0.26). Baseline clinical factors associated with earlier dialysis initiation were lower baseline estimated glomerular filtration rate (hazard ratio [HR] associated with 5-unit decrease, 2.08 [95% CI, 1.72-2.56]; P<0.001), diabetes (HR, 2.30 [95% CI, 1.28-4.13]; P=0.005), hypertension (HR, 7.97 [95% CI, 1.09-58.21]; P=0.041), and Hispanic ethnicity (HR, 2.34 [95% CI, 1.22-4.47]; P=0.010). Conclusions In participants with non-dialysis-requiring CKD in ISCHEMIA-CKD, randomization to an invasive chronic coronary disease management strategy (relative to a conservative chronic coronary disease management strategy) is associated with an accelerated time to initiation of maintenance dialysis for kidney failure.U01 HL117904/HL/NHLBI NIH HHS/United Statesinfo:eu-repo/semantics/publishedVersio
Understanding Study Drug Discontinuation Through EUCLID
Introduction: Disparities in the care and outcomes of peripheral artery disease (PAD) have been well-established. In part this is due to disparities in enrollment of PAD trial cohorts. However, less attention has been paid to non-random protocol non-adherence after enrollment, which may lead to inaccurate estimates of treatment effects and reduce generalizability of study results. We aimed to ascertain characteristics associated with premature study drug discontinuation in a PAD cohort.Methods: Using data from EUCLID (Examining Use of Ticagrelor in Peripheral Artery Disease), factors associated with study drug discontinuation were assessed using univariable and multivariable Cox proportional hazards models with time to study drug discontinuation as the outcome of interest. Relationships between study drug discontinuation and major adverse cardiovascular events (MACE; cardiovascular death, myocardial infarction, ischemic stroke), major adverse limb events (MALE; acute limb ischemia, major amputation, and lower extremity revascularization), and all-cause hospitalization were assessed.Results: Of 13,842 eligible EUCLID participants, 3,886 (28.1%) prematurely and permanently discontinued study drug over a maximum follow-up of 42 months (annualized rate of 13.2 discontinuations per 100 patient-years). In a multivariable model, premature study drug discontinuation was associated with older age (aHR 1.16, 95%CI 1.14-1.19), eligibility based on prior lower extremity revascularization rather than ABI/TBI criteria (aHR 1.14, 95%CI 1.06-1.23), CLI status (aHR 1.23, 95%CI 1.06-1.42), COPD (aHR 1.36, 95%CI 1.24-1.49), and geographic region. In a multivariable analysis, study drug discontinuation was significantly associated with MACE (aHR 3.27, 95%CI 2.90-3.67, p p Conclusions: This analysis of EUCLID demonstrates that premature, permanent discontinuation of study drug is relatively common in more than a quarter of PAD patients, is unevenly distributed based on geography and other baseline characteristics, and is associated with worse outcomes in a clinical trial context. Study teams leading future PAD trials may want to address the possibility of study drug discontinuation prospectively, as a proactive approach may help investigators to maintain study cohort diversity and representativeness without sacrificing power and precision.</p
The preburning condition of Chalcolithic cremated human remains from the Perdigoes enclosures (Portugal)
The Iberian Chalcolithic displayed a remarkable variety of funerary practices, which has been related to interpopulation differences, intrapopulation social-cultural differences, and complex multistage funerary rituals. Perdigoes, a Chalcolithic set of ditched enclosures, reflects such diversity including a wide array of funerary practices. Among those practices is cremation, which, despite relatively rare, is represented in different structures in Perdigoes. One of these structures (Pit 40) presents an unparalleled high minimum number of individuals (n = 240), contrasting with nearby and coeval structures. In this study, we analyse heat-induced bone changes and other archaeothanatological variables to tentatively assess the preburning condition of the human remains. The results of Pit 40 are also compared with other comparable contexts to assess if this unique context presents further funerary differences relative to those other contexts in, for example, body processing. Our results suggest preferential cremation of fleshed human remains, but burning of at least a minority of skeletonised remains and deposition of possibly unburned remains also likely occurred. Body processing appears to be comparable with that of the cremation contexts of Perdigoes but contrasts with that of another nearby context (Dolmen of Olival da Pega 2b) in which burned bones were also found.Portuguese Foundation for Science and TechnologyPortuguese Foundation for Science and Technology [PEst-OE/SADG/UI0283/2013, POCI-01-0145-FEDER-016766, PTDC/EPH-ARQ/0798/2014, PTDC/IVC-ANT/1201/2014, SFRH/BPD/84268/2012]info:eu-repo/semantics/publishedVersio
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Treatability Test Plan for 300 Area Uranium Stabilization through Polyphosphate Injection
The U.S. Department of Energy has initiated a study into possible options for stabilizing uranium at the 300 Area using polyphosphate injection. As part of this effort, PNNL will perform bench- and field-scale treatability testing designed to evaluate the efficacy of using polyphosphate injections to reduced uranium concentrations in the groundwater to meet drinking water standards (30 ug/L) in situ. This technology works by forming phosphate minerals (autunite and apatite) in the aquifer that directly sequester the existing aqueous uranium in autunite minerals and precipitates apatite minerals for sorption and long term treatment of uranium migrating into the treatment zone, thus reducing current and future aqueous uranium concentrations. Polyphosphate injection was selected for testing based on technology screening as part of the 300-FF-5 Phase III Feasibility Study for treatment of uranium in the 300-Area
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