13 research outputs found
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A field-scale demonstration of air sparging to remediate tritiated fluids
Two pilot field-scale studies were conducted during the period of May 24 to July 22, 1996, to evaluate the potential of air sparging to remediate tritiated fluids. Previous analytical solutions to the rate of tritium removal were evaluated and compared to the experimental results. The analytical solution of Craig and Gordon that describes isotopic fractionation of an evaporating body of water appears to most accurately describe the process, versus the more limited isotopic exchange equation of Slattery and Ingraham and the mass transfer equation of Wilson and Fordham, which are accurate only at moderate to high humidities and do not describe the tritium enrichment process that would occur at low humidities. The results of the two experiments demonstrated that air sparging of tritium is a viable process in the field. Tritium removal rates of 60 percent were reported during the first experiment and 66 percent for the second experiment. Comparison to previous laboratory work revealed that rates could have been improved by starting with higher concentrations, utilizing smaller bubbles, and longer bubble path lengths. Risks associated with the pilot study were greater the closer one worked to the experiment with a maximum increase in the Lifetime Excess Total Risk per Unit Uptake of 2.4 x 10{sup -5}. Conduct of this experiment at locations with much higher activities of tritium would significantly increase the associated risk
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Hydrologic Data and Evaluation for Model Validation Wells, MV-1, MV-2, and MV-3 near the Project Shoal Area
In 2006, a drilling campaign was conducted at the Project Shoal Area (PSA) to provide information for model validation, emplace long-term monitoring wells, and develop baseline geochemistry for long term hydrologic monitoring. Water levels were monitored in the vicinity of the drilling, in the existing wells HC-1 and HC-6, as well as in the newly drilled wells, MV-1, MV-2 and MV-3 and their associated piezometers. Periodic water level measurements were also made in existing wells HC-2, HC-3, HC-4, HC-5 and HC-7. A lithium bromide chemical tracer was added to drilling fluids during the installation of the monitoring and validation (MV) wells and piezometers. The zones of interest were the fractured, jointed and faulted horizons within a granitic body. These horizons generally have moderate hydraulic conductivities. As a result, the wells and their shallower piezometers required strenuous purging and development to remove introduced drilling fluids as evidenced by bromide concentrations. After airlift and surging well development procedures, the wells were pumped continuously until the bromide concentration was less then 1 milligram per liter (mg/L). Water quality samples were collected after the well development was completed. Tritium scans were preformed before other analyses to ensure the absence of high levels of radioactivity. Tritium levels were less than 2,000 pico-curies per liter. Samples were also analyzed for carbon-14 and iodine-129, stable isotopes of oxygen and hydrogen, as well as major cations and anions. Aquifer tests were performed in each MV well after the bromide concentration fell below acceptable levels. Water level data from the aquifer tests were used to compute aquifer hydraulic conductivity and transmissivit
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Early Intervention in Low-Birth-Weight Premature Infants: Results Through Age 5 Years From the Infant Health and Development Program
Objective.—To evaluate the persistence of effects on health and development at age 5 years of the Infant Health and Development Program, an early childhood intervention that was provided to low-birth-weight (LBW) premature infants from neonatal discharge through age 3 years.Design.—Randomized, controlled, multicenter trial, stratified by two LBW groups: lighter (≤2000 g) and heavier (2001 to 2500 g).Setting.—Eight socioeconomically heterogeneous clinical sites.Participants.—Of 985 eligible infants weighing 2500 g or less and at 37 weeks' or less gestational age, 377 infants were randomly assigned to the intervention group and 608 to the follow-up only group. About two thirds of the infants in each group were in the lighter LBW stratum, and one third were in the heavier LBW stratum.Intervention.—The intervention group received home visits (from neonatal discharge through age 3 years) as well as center-based schooling (from 1 to 3 years of age). Children in both groups received pediatric surveillance.Main Outcome Measures.—Cognitive development, behavioral competence, and health status.Results.—At age 5 years, the intervention group had full-scale IQ scores similar to children in the follow-up only group. However, in the heavier LBW stratum, children in the intervention group had higher full-scale IQ scores (3.7 points higher; P=.03) and higher verbal IQ scores (4.2 points higher; P=.02). No significant differences between intervention and follow-up only groups in cognitive measures at age 5 years were noted in the lighter LBW infants. The intervention and follow-up groups were similar in behavior and health measures regardless of LBW stratum.Conclusion.—The early childhood intervention provided in the first 3 years of life had effects on heavier LBW premature infants' IQ and verbal performance at age 5 years that were not observed for lighter LBW premature infants. The intervention did not affect health or behavior at age 5 years in either LBW stratum.(JAMA. 1994;272:1257-1262
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Morbidity and Toxic Effects Associated With Ganciclovir or Foscarnet Therapy in a Randomized Cytomegalovirus Retinitis Trial
BACKGROUND: The Foscarnet-Ganciclovir Cytomegalovirus Retinitis Trial compared the use of either ganciclovir or foscarnet for the initial treatment of cytomegalovirus retinitis in patients with the acquired immunodeficiency syndrome. We previously reported that patients treated with foscarnet lived longer but were more likely to have their treatment switched, the latter suggesting foscarnet may not have been as well tolerated as ganciclovir. This study compared the morbidity and toxic reactions reported during the trial. METHODS: Two hundred thirty-four patients with the acquired immunodeficiency syndrome and previously untreated cytomegalovirus retinitis at 11 university centers were randomly assigned to receive intravenously either foscarnet (n=107) or ganciclovir (n=127). Medical histories, laboratory tests, and drug treatment histories during the first 6 months of treatment were analyzed. RESULTS: Neutropenia was more common in patients assigned to ganciclovir than to foscarnet (34% vs 14%; P=.001). Patients assigned to foscarnet reported more infusion-related symptoms (58% vs 24%; P.001); they also experienced a trend toward more nephrotoxic effects (13% vs 6%; P=.082) and electrolyte abnormalities. The incidence of seizures was similar in both groups (foscarnet, 12%; ganciclovir, 9%; P=.511). Patients assigned to foscarnet were more likely to be switched to the alternative treatment (foscarnet to ganciclovir, 46%; ganciclovir to foscarnet, 11%; P<.001), and most of this excess was attributable to toxic reactions. In 88% of cases in which treatment was switched as a result of toxic reactions and in which follow-up data were available, the toxic reaction resolved after the switch. No permanent disability or death resulted from toxic reactions. CONCLUSIONS: Compared with ganciclovir, the use of foscarnet was more frequently limited by the occurrence of toxic reactions. However, these toxic reactions rarely had long-term sequelae. In light of the previously reported survival benefit seen in patients treated with foscarnet, these data support the use of foscarnet for the initial treatment of cytomegalovirus retinitis.(Arch Intern Med. 1995;155:65-74
Patient Sex, Reproductive Status, and Synthetic Hormone Use Associate With Histologic Severity of Nonalcoholic Steatohepatitis.
Background & aimsSex and sex hormones can affect responses of patients with nonalcoholic fatty liver disease (NAFLD) to metabolic stress and development of hepatocyte injury and inflammation.MethodsWe collected data from 3 large U.S. studies of patients with NAFLD (between October 2004 and June 2013) to assess the association between histologic severity and sex, menopause status, synthetic hormone use, and menstrual abnormalities in 1112 patients with a histologic diagnosis of NAFLD. We performed logistic or ordinal logistic regression models, adjusting for covariates relevant to an increase of hepatic metabolic stress.ResultsPremenopausal women were at an increased risk of lobular inflammation, hepatocyte ballooning, and Mallory-Denk bodies than men and also at an increased risk of lobular inflammation and Mallory-Denk bodies than postmenopausal women (P < .01). Use of oral contraceptives was associated with an increased risk of lobular inflammation and Mallory-Denk bodies in premenopausal women, whereas hormone replacement therapy was associated with an increased risk of lobular inflammation in postmenopausal women (P < .05).ConclusionsBeing a premenopausal woman or a female user of synthetic hormones is associated with increased histologic severity of hepatocyte injury and inflammation among patients with NAFLD at given levels of hepatic metabolic stress