► Nanomaterial-containing wastes are placed in MSW landfills. ► Little work evaluating nanomaterial behavior in solid waste has been conducted. ► Humic acid stabilizes carbon nanotubes in leachate, ...even at high ionic strengths. ► Carbon nanotubes may be mobile through solid waste. ► Nanomaterial placement within landfills needs to be examined more closely.
Escalating production and subsequent incorporation of engineered nanomaterials in consumer products increases the likelihood of nanomaterials being discarded in landfills. Although direct measurement of particle disposal has not yet occurred, life cycle assessments suggest that over 50% of nanomaterials produced will eventually reside in landfills. Laboratory-scale experiments were conducted to evaluate how organics (humic acid: 20–800mg/L), ionic strength (100–400mM NaCl), and pH (6–8) typical of mature leachates influence carbon nanotube surface charge, relative stability, and mobility through representative solid waste environments. Results from the batch experiments suggest that the presence of high molecular weight organics, such as humic acid, acts to stabilize carbon nanotubes present in leachate, even at high ionic strengths (>100mM NaCl). These results also suggest that in mature landfill leachate, as long as humic acid is present, ionic strength (when represented as NaCl) will be a dominant factor influencing nanomaterial stability. Column experiment results indicate the carbon nanotubes may be mobile through solid waste, suggesting particle placement within landfills needs to be examined more closely.
Eutrophication of most fresh water systems is limited by phosphorus (P) concentration. High P concentrations originate from external and internal sources. In most Norwegian lakes, agriculture is a ...main external contributor of P. Two long-term, integrated studies of the relationship between agricultural management, transfer of P and suspended sediments (SS) from agricultural areas and the total P (TP) and chlorophyll-a (Chl-a) concentrations of the receiving lake were carried out in Norway. The Grimestad subcatchment/Aker Lake system (1993–2000) represents a cereal-growing area with mixed livestock production, while the Time subcatchment/Frøyland Lake (1986–2000) system represents a grass and dairy cow production system. A comparison of the two systems showed that the mean annual concentration of SS in the Grimestad Stream was 20 times the corresponding concentration in the Time stream. The difference in transparency (secchi depth) of the two lakes reflected this difference. The losses of TP and SS from the Grimestad subcatchment increased significantly during the monitoring period. In the Time stream, there was a significant downward trend in concentrations of TP. Corresponding to the measured inputs, the TP concentration of the Aker Lake (recipient of Grimestad Stream) increased slightly during the monitoring period, while the TP concentration of the Frøyland Lake (recipient of Time Stream) showed a slightly decreasing trend. Loads of TP from the Grimestad subcatchment during spring (March–April) described 70% of the variation in TP concentration of the Aker Lake the following summer. The TP concentration in the Time stream in November–December also were correlated (
r
2=0.6) to the TP concentration in the Frøyland Lake the following summer. The annual TP concentrations of the lakes were not very well correlated to the measured Chl-a in the lakes, partly because of bio-manipulation, which was performed in both lakes during the monitoring period.
Treatment of dense nonaqueous phase liquid (DNAPL) source zones using suspensions of reactive iron particles relies upon effective transport of the nano- to submicrometer scale iron particles within ...the subsurface. Recognition that poor subsurface transport of iron particles results from particle−particle and particle−soil interactions permits development of strategies which increase transport. In this work, experiments were conducted to assess a novel approach for encapsulated delivery of iron particles within porous media using oil-in-water emulsions. Objectives of this study included feasibility demonstration of producing kinetically stable, iron-containing, oil-in-water emulsions and evaluating the transport of these iron-containing, oil-in-water emulsions within water-saturated porous media. Emulsions developed in this study have mean droplet diameters between 1 and 2 μm, remain kinetically stable for >1.5 h, and possess densities (0.996−1.00 g/mL at 22 °C) and dynamic viscosities (2.4−9.3 mPa·s at 22 °C and 20 s−1) that are favorable to transport within DNAPL source zones. Breakthrough curves and post-experiment extractions from column experiments conducted with medium and fine sands suggest little emulsion retention (<0.20% wt) at a Darcy velocity of 0.4 m/day. These findings demonstrate that emulsion encapsulation is a promising method for delivery of iron particles and warrants further investigation.
Background Lower extremity arterial revascularization (LEAR) is the gold-standard for critical lower limb ischemia (CLI). The goal of this study was twofold. First, we evaluated the long-term ...functional status of patients undergoing primary LEAR for CLI. Second, prognostic factors of long-term functional status and survival after primary LEAR for CLI were assessed. Methods All primary LEAR procedures were analyzed. Patients were stratified by preoperative functional status: ambulatory (group I) vs nonambulatory (group II). Patients were followed-up after 3 and 6 years. Adverse events (AEs) were categorized according to predefined standards: minor, surgical, failed revascularization, and systemic. Associated patient demographic/clinical data were analyzed using univariate and multivariate methods. Results There were 106 LEAR patients (group I: n = 42, 40% vs group II: n = 64, 60%). Group II patients were significantly older (75 vs 62 years; P = .00), were classified ASA 3-4 more frequently (78% vs 52%; P < .02), had more cardiac disease (n = 42, 66% vs n = 10, 24%; P = .00), renal disease (n = 26, 41% vs n = 7, 17%; P = .00), diabetes (n = 36, 56% vs n = 8, 19%; P = .00), hypertension (n = 47, 73% vs n = 13, 31%; P = .00) and severe CLI (n = 42, 66% vs n = 18, 38%; P < .01). Group II patients had a higher incidence of death (65.6% vs 14.3%; P = .00), minor AEs (n = 38, 26% vs n = 10, 22%; P = .00), surgical AEs (n = 48, 33% vs n = 12, 26%; P < .02) and systemic AEs (n = 24, 86% vs n = 4, 9%; P < .02). Also more unplanned reinterventions occurred in group II (n = 148, 76% vs n = 47, 24%; P = .00). Nonambulatory status was a multivariate independent predictor of nonambulatory status after LEAR during 6 years follow-up (odds ration OR: 21.47; 95% confidence interval CI: 2.76-166.77; P = .00). Pulmonary disease (OR: 7.49; 95% CI: 2.17-25.80; P = .00), not prescribing β-blockers (OR: 4.67; 95% CI: 1.28-17.03; P < .02), nonambulatory status (OR: 22.99; 95% CI: 6.27-84.24; P = .00), and systemic AEs (OR: 9.66; 95% CI: 1.84-50.57; P < .01) were independent predictors of death. Functional status was not improved in group II after long-term follow-up. Conclusion Nonambulatory patients suffer from extensive comorbid conditions. They are accompanied with an increased occurrence of AEs, unplanned reinterventions, and poor long-term survival rates. Successful LEAR did not improve their functional status after 6 years. This emphasizes that attempts for limb salvage must be carefully considered in these patients.
Abstract Objectives The aim of this study was to evaluate patients, who underwent spiral vein reconstruction of the abdominal aorta to repair infected aneurysms or replace infected aortic grafts. ...Methods All spiral vein reconstructions between March 2005 and May 2010 because of vascular infections of the abdominal aorta were retrospectively included. Diagnosis was determined by clinical examination, laboratory results, computed tomography (CT) and positron emission tomography (PET) scan, and microbiological tests. Spiral vein reconstruction consisted of harvesting the greater saphenous vein (GSV) and construction into a spiral graft, aortic reconstruction and a transmesenteric omentumplasty. Primary outcomes were survival and limb salvage. Secondary outcomes included technical, clinical and ongoing success, re-infection, ongoing infection and patency. Results All five patients survived surgery, and there were no in-hospital deaths. Survival and limb salvage were 100% after median follow-up of 13 months (6–67 months). Further, technical, clinical and continuing success was 100%. There were no re-infections or ongoing infections. Conclusions Spiral vein reconstruction using the GSV showed good short-term survival and limb salvage. It, therefore, might be considered as an attractive treatment method for vascular infections of the abdominal aorta. Still, more follow-up is needed to evaluate long-term results.
•Carbonization of municipal wastes was conducted over time at 250°C.•Carbonization occurred in the presence of alternative initial liquid sources.•Activated sludge and landfill leachate are ...acceptable alternative supplemental liquid sources.•Feedstock initial carbon content is more influential than the initial liquid source.
Hydrothermal carbonization (HTC) is a thermal conversion process that can be an environmentally beneficial approach for the conversion of municipal solid wastes to value-added products. The influence of using activated sludge and landfill leachate as initial moisture sources during the carbonization of paper, food waste and yard waste over time at 250°C was evaluated. Results from batch experiments indicate that the use of activated sludge and landfill leachate are acceptable alternative supplemental liquid sources, ultimately imparting minimal impact on carbonization product characteristics and yields. Regression results indicate that the initial carbon content of the feedstock is more influential than any of the characteristics of the initial liquid source and is statistically significant when describing the relationship associated with all evaluated carbonization products. Initial liquid-phase characteristics are only statistically significant when describing the solids energy content and the mass of carbon in the gas-phase. The use of these alternative liquid sources has the potential to greatly increase the sustainability of the carbonization process. A life cycle assessment is required to quantify the benefits associated with using these alternative liquid sources.
Microcosm experiments aimed at defining a rate equation that describes how different environmental conditions (i.e., gas-phase oxygen concentrations, temperature and ammonia concentration) may impact ...in situ ammonia removal were conducted. Results indicate that ammonia removal can readily occur at various gas-phase oxygen levels (between 0.7% and 100%) and over a range of temperatures (22, 35 and 45
°C). Slowest rates occurred with lower gas-phase oxygen concentrations. All rate data, except at 45
°C and 5% oxygen, fit well (
r
2=0.75) to a multiplicative Monod equation with terms describing the impact of oxygen, pH, temperature and ammonia concentration. All ammonia half-saturation values are relatively high when compared to those generally found in wastewater treatment, suggesting that the rate may be affected by the mass transfer of oxygen and/or ammonia. Additionally, as the temperature increases, the ammonia half-saturation value also increases. The multiplicative Monod model developed can be used to aid in designing and operating field-scale studies.
The sustainability of energy production can be increased by combusting waste-derived solid fuels, alone or as blends with coal. This paper investigated whether two thermochemical processes ...(hydrothermal carbonization and pyrolysis) can be used in sustainable manure management systems to convert surplus manure waste streams into renewable fuels. Hydrochars and pyrochars derived from swine manure and poultry litter at various process conditions were characterized. Their combustion behavior was studied by thermogravimetric analysis, individually and simulated as a blend with fossil coal. The hydrochars underwent two combustion stages, active and char combustion, while the pyrochars and four fossil coals showed only one stage. The substantial differences in characteristic combustion temperatures, kinetic parameters, and ash content between animal-manure-derived chars and coal suggest that fossil coals should not be replaced entirely with char, but used preferably as a blend. Simulation of blends with coal showed combustion characteristics similar to coal alone with amounts up to 10% (hydrochar) and 80% (pyrochar). Although more scale-up and ash characterization study is needed before implementation, the results suggest high potential of cocombusting small percentages of animal-manure based hydrochar and pyrochar with coal in existing coal power generation facilities.
To describe similarities and differences between health status and quality of life in patients with intermittent claudication.
This was an observational study in the vascular outpatient department of ...a teaching hospital; it concerned 200 consecutive patients with intermittent claudication. Health status was assessed with the RAND-36, and quality of life was assessed with a reduced version of the World Health Organization Quality of Life assessment instrument-100. Scores were compared with those of sex- and age-matched healthy controls. Mann-Whitney
U tests were used to detect statistically significant differences (
P < .01) between patients and healthy controls. Pearson correlations were calculated between health status and quality-of-life scores. Differences between correlations were examined by using Fisher
z statistics. The upper and lower 10% of quality-of-life scores were compared with the response quartiles of the health status scores.
Health status was significantly impaired in all domains. Quality of life was significantly worse with respect to aspects of physical health and level of independence and one global evaluative facets overall quality of life and general health. Quality-of-life assessment with the World Health Organization Quality of Life instrument disclosed patient-reported problems that had not been identified in health status. Conversely, patients did not regard all objective functional impairments as a problem. Pearson correlations ranged from 0.20 to 0.74. There were patients with excellent and very poor quality-of-life scores in nearly all the quartiles of the corresponding health status domains.
Health status and quality of life represent different outcomes in patients with intermittent claudication. In addition to functional restrictions as measured in health status, quality of life also permits a personal evaluation of these restrictions. Objective functioning and subjective appraisal of functioning are complementary and not identical. Combining these measures should direct treatment in a way that meets patients' needs.
PDF
