bluuebunny/crossref_metadata_2025_split huggingface dataset:
Environmental Impacts of Training Activities at an Air Weapons Range
Authors: Bordeleau Geneviève , Martel Richard , Ampleman Guy , Thiboutot Sonia 
Published: February 2008

AbstractWithin Canada, it has been recognized in the last decade that military training activities may have impacts on the environmental quality of training ranges. However, impacts of activities specific to Air Force Bases have not yet been intensely documented. A hydrogeological study was accomplished at the Cold Lake Air Weapons Range, Alberta, to evaluate the environmental impacts of using bombs, rockets, strafing, and open burning/open detonation (OB/OD) on the quality of soil, ground water, surface water, and lake sediments. Samples were analyzed for metals, anions, ammonium perchlorate (NH4ClO4), and energetic materials (EM). It was found that training activities did not result in measured values being exceeded on the basis of guidance values for surface water and lake sediments. Contamination by metals was mostly limited to soils, and some metals may be related to the use of bombs (Cd, Cu, Pb), strafe (Cu), and rockets (As, Ba, Cd, Cr, Cu, Fe, Ni, Pb, U, V, Zn). TNT (2,4,6‐trinitrotoluene) was the main EM found in soils, while RDX (hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine) was more common in ground water. Both are related to live bombing, while nitroglycerine (NG) is related to rocket use and was detected in soils only. Aluminum, nitrate, and ammonium perchlorate detected in ground water may be related to live bombing or rockets. OB/OD operations resulted in the presence of various EM in soils, and of perchlorate and nitrate in ground water. Contamination by metals and explosives in soils was localized around the targets and varied significantly in time; however, in ground water it was more constant and may persist for a period of several years after a target has been removed.
Metal Release from Bottom Sediments of Ocoee Lake No. 3, a Primary Catchment Area for the Ducktown Mining District
Authors: Lee Giehyeon , Faure Gunter , Bigham Jerry M. , Williams David J. 
Published: February 2008

AbstractOcoee Lake No. 3 is the first reservoir receiving suspended sediments contaminated with trace metals discharged by acid mine effluents from the Ducktown Mining District, Tennessee. Bottom sediments (0–5 cm) from the lake were sampled to assess the potential for future adverse environmental effects if no remediation controls or activities are implemented. The sediments were found to include a major component (173 ± 19 g kg−1) that dissolved in 6 mol L−1 HCl within 24 h. This acid‐soluble and relatively labile fraction contained high concentrations of Fe (460 ± 40 g kg−1), Al (99 ± 11 g kg−1), Mn (10 ± 8 g kg−1), Cu (2000 ± 700 mg kg−1), Zn (1300 ± 200 mg kg−1), and Pb (300 ± 200 mg kg−1). When the pH of water in contact with the sediment was decreased experimentally from 6.4 to 2.6, the concentrations of dissolved trace metals increased by factors of 2200 for Pb, 160 for Cu, 21 for Zn, 9 for Cd, 8 for Ni, and 5 for Co. The order in which metals were released with decreasing pH was the reverse of that reported for pH‐dependent sorption of these metals in upstream systems. Substantial release of trace metals from the sediment was observed even by a modest decrease of pH from 6.4 to 5.9. Therefore, the metal‐rich sediment of the lake should be considered as potentially hazardous to bottom‐dwelling aquatic species and other organisms in the local food chain. In addition, if the reservoir is dredged or if the dam is removed, the accumulated sediment may have to be treated for recovery of sorbed metals.
Water Quality Modeling of Fertilizer Management Impacts on Nitrate Losses in Tile Drains at the Field Scale
Authors: Nangia V. , Gowda P. H. , Mulla D. J. , Sands G. R. 
Published: February 2008

AbstractNitrate losses from subsurface tile drained row cropland in the Upper Midwest U.S. contribute to hypoxia in the Gulf of Mexico. Strategies are needed to reduce nitrate losses to the Mississippi River. This paper evaluates the effect of fertilizer rate and timing on nitrate losses in two (East and West) commercial row crop fields located in south‐central Minnesota. The Agricultural Drainage and Pesticide Transport (ADAPT) model was calibrated and validated for monthly subsurface tile drain flow and nitrate losses for a period of 1999–2003. Good agreement was found between observed and predicted tile drain flow and nitrate losses during the calibration period, with Nash‐Sutcliffe modeling efficiencies of 0.75 and 0.56, respectively. Better agreements were observed for the validation period. The calibrated model was then used to evaluate the effects of rate and timing of fertilizer application on nitrate losses with a 50‐yr climatic record (1954–2003). Significant reductions in nitrate losses were predicted by reducing fertilizer application rates and changing timing. A 13% reduction in nitrate losses was predicted when fall fertilizer application rate was reduced from 180 to 123 kg/ha. A further 9% reduction in nitrate losses can be achieved when switching from fall to spring application. Larger reductions in nitrate losses would require changes in fertilizer rate and timing, as well as other practices such as changing tile drain spacings and/or depths, fall cover cropping, or conversion of crop land to pasture.
The Impact of Alum Addition on Organic P Transformations in Poultry Litter and Litter‐Amended Soil
Authors: Warren Jason G. , Penn Chad J. , McGrath Joshua M. , Sistani Karamat 
Published: February 2008

AbstractPoultry litter treatment with alum (Al2(SO4)3·18H2O) lowers litter phosphorus (P) solubility and therefore can lower litter P release to runoff after land application. Lower P solubility in litter is generally attributed to aluminum‐phosphate complex formation. However, recent studies suggest that alum additions to poultry litter may influence organic P mineralization. Therefore, alum‐treated and untreated litters were incubated for 93 d to assess organic P transformations during simulated storage. A 62‐d soil incubation was also conducted to determine the fate of incorporated litter organic P, which included alum‐treated litter, untreated litter, KH2PO4 applied at 60 mg P kg−1 of soil, and an unamended control. Liquid‐state 31P nuclear magnetic resonance indicated that phytic acid was the only organic P compound present, accounting for 50 and 45% of the total P in untreated and alum‐treated litters, respectively, before incubation and declined to 9 and 37% after 93 d of storage‐simulating incubation. Sequential fractionation of litters showed that alum addition to litter transformed 30% of the organic P from the 1.0 mol L−1 HCl to the 0.1 mol L−1 NaOH extractable fraction and that both organic P fractions were more persistent in alum‐treated litter compared with untreated litter. The soil incubation revealed that 0.1 mol L−1 NaOH–extractable organic P was more recalcitrant after mixing than was the 1.0 mol L−1 HCl–extractable organic P. Thus, adding alum to litter inhibits organic P mineralization during storage and promotes the formation of alkaline extractable organic P that sustains lower P solubility in the soil environment.
Rhamnolipid Morphology and Phenanthrene Solubility at Different pH Values
Authors: Shin Kyung‐Hee , Kim Kyoung‐Woong , Kim Ju‐Yong , Lee Kyung‐Eun , Han Sung‐Sik 
Published: February 2008

AbstractThe effect of pH and rhamnolipids on the solubility of phenanthrene was investigated in a sand–water system. Batch phenanthrene solubilization experiments in this system showed that the highest phenanthrene solubility occurred at pH 5 in the presence of 240 and 150 mg L−1 rhamnolipids. As the pH was increased from 5 to 7, the apparent solubility of phenanthrene decreased and then stabilized from pH 7 to 8. At pH 4, a dramatic decrease in phenanthrene solubility was observed. This result is in contrast to previous findings obtained in an aqueous system without soil particles. To investigate the reason for this decrease, the critical micelle concentrations (CMCs) were measured in the presence or absence of sand particles, and the maximum amount of sorbed biosurfactant at each pH was calculated based on the differences of the two CMC values. More rhamnolipid molecules were lost by the sorption into sand particles at pH 4 than at other pH values; this explains the dramatic decrease of solubility at pH 4 in the sand–water system. To confirm the explanation for the different solubilizing capacity that results from the structural change of biosurfactant aggregate, cryo‐transmission electron microscopy was used. Micrographs showed that the rhamnolipid morphology changed from large lamellar sheets, to vesicle, and then to micelle as the pH increased. The large and multilamellar vesicles at pH 5 were considered to be the most effective structure for the solubilization of phenanthrene.
In Situ Bioreactors and Deep Drain‐Pipe Installation to Reduce Nitrate Losses in Artificially Drained Fields
Authors: Jaynes Dan B. , Kaspar Tom C. , Moorman Tom B. , Parkin Tim B. 
Published: February 2008

AbstractNitrate in water removed from fields by subsurface drain (‘tile’) systems is often at concentrations exceeding the 10 mg N L−1 maximum contaminant level (MCL) set by the USEPA for drinking water and has been implicated in contributing to the hypoxia problem within the northern Gulf of Mexico. Because previous research shows that N fertilizer management alone is not sufficient for reducing NO3 concentrations in subsurface drainage below the MCL, additional approaches are needed. In this field study, we compared the NO3 losses in tile drainage from a conventional drainage system (CN) consisting of a free‐flowing pipe installed 1.2 m below the soil surface to losses in tile drainage from two alternative drainage designs. The alternative treatments were a deep tile (DT), where the tile drain was installed 0.6 m deeper than the conventional tile depth, but with the outlet maintained at 1.2 m, and a denitrification wall (DW), where trenches excavated parallel to the tile and filled with woodchips serve as additional carbon sources to increase denitrification. Four replicate 30.5‐ by 42.7‐m field plots were installed for each treatment in 1999 and a corn–soybean rotation initiated in 2000. Over 5 yr (2001–2005) the tile flow from the DW treatment had annual average NO3 concentrations significantly lower than the CN treatment (8.8 vs. 22.1 mg N L−1). This represented an annual reduction in NO3 mass loss of 29 kg N ha−1 or a 55% reduction in nitrate mass lost in tile drainage for the DW treatment. The DT treatment did not consistently lower NO3 concentrations, nor reduce the annual NO3 mass loss in drainage. The DT treatment did exhibit lower NO3 concentrations in tile drainage than the CN treatment during late summer when tile flow rates were minimal. There was no difference in crop yields for any of the treatments. Thus, denitrification walls are able to substantially reduce NO3 concentrations in tile drainage for at least 5 yr.
Assessment of Chlorophyll‐a as a Criterion for Establishing Nutrient Standards in the Streams and Rivers of Illinois
Authors: Royer Todd V. , David Mark B. , Gentry Lowell E. , Mitchell Corey A. , Starks Karen M. , Heatherly Thomas , Whiles Matt R. 
Published: February 2008

AbstractNutrient enrichment is a frequently cited cause for biotic impairment of streams and rivers in the USA. Efforts are underway to develop nutrient standards in many states, but defensible nutrient standards require an empirical relationship between nitrogen (N) or phosphorus (P) concentrations and some criterion that relates nutrient levels to the attainment of designated uses. Algal biomass, measured as chlorophyll‐a (chl‐a), is a commonly proposed criterion, yet nutrient–chl‐a relationships have not been well documented in Illinois at a state‐wide scale. We used state‐wide surveys of >100 stream and river sites to assess the applicability of chl‐a as a criterion for establishing nutrient standards for Illinois. Among all sites, the median total P and total N concentrations were 0.185 and 5.6 mg L−1, respectively, during high‐discharge conditions. During low‐discharge conditions, median total P concentration was 0.168 mg L−1, with 25% of sites having a total P of ≥0.326 mg L−1 Across the state, 90% of the sites had sestonic chl‐a values of ≤35 μg L−1, and watershed area was the best predictor of sestonic chl‐a During low discharge there was a significant correlation between sestonic chl‐a and total P for those sites that had canopy cover ≤25% and total P of ≤0.2 mg L−1 Results suggest sestonic chl‐a may be an appropriate criterion for the larger rivers in Illinois but is inappropriate for small rivers and streams. Coarse substrate to support benthic chl‐a occurred in <50% of the sites we examined; a study using artificial substrates did not reveal a relationship between chl‐a accrual and N or P concentrations. For many streams and rivers in Illinois, nutrients may not be the limiting factor for algal biomass due to the generally high nutrient concentrations and the effects of other factors, such as substrate conditions and turbidity.
Phosphorus Loss from an Agricultural Watershed as a Function of Storm Size
Authors: Sharpley Andrew N. , Kleinman Peter J. A. , Heathwaite A. Louise , Gburek William J. , Folmar Gordon J. , Schmidt John P. 
Published: February 2008

AbstractPhosphorus (P) loss from agricultural watersheds is generally greater in storm rather than base flow. Although fundamental to P‐based risk assessment tools, few studies have quantified the effect of storm size on P loss. Thus, the loss of P as a function of flow type (base and storm flow) and size was quantified for a mixed‐land use watershed (FD‐36; 39.5 ha) from 1997 to 2006. Storm size was ranked by return period (<1, 1–3, 3–5, 5–10, and >10 yr), where increasing return period represents storms with greater peak and total flow. From 1997 to 2006, storm flow accounted for 32% of watershed discharge yet contributed 65% of dissolved reactive P (DP) (107 g ha−1 yr−1) and 80% of total P (TP) exported (515 g ha−1 yr−1). Of 248 storm flows during this period, 93% had a return period of <1 yr, contributing most of the 10‐yr flow (6507 m3 ha−1; 63%) and export of DP (574 g ha−1; 54%) and TP (2423 g ha−1; 47%). Two 10‐yr storms contributed 23% of P exported between 1997 and 2006. A significant increase in storm flow DP concentration with storm size (0.09–0.16 mg L−1) suggests that P release from soil and/or area of the watershed producing runoff increase with storm size. Thus, implementation of P‐based Best Management Practice needs to consider what level of risk management is acceptable.
The New Gold Rush: Fueling Ethanol Production while Protecting Water Quality
Authors: Simpson Thomas W. , Sharpley Andrew N. , Howarth Robert W. , Paerl Hans W. , Mankin Kyle R. 
Published: February 2008

AbstractRenewable fuel production, particularly grain‐based ethanol, is expanding rapidly in the USA. Although subsidized grain‐based ethanol may provide a competitively priced transportation fuel, concerns exist about potential environmental impacts. This contribution focuses on potential water quality implications of expanded grain‐based ethanol production and potential impacts of perennial‐grass–based cellulosic ethanol. Expanded grain‐based ethanol will increase and intensify corn production. Even with recommended fertilizer and land conservation measures, corn acreage can be a major source of N loss to water (20–40 kg ha−1 yr−1). A greater acreage of corn is estimated to increase N and P loss to water by 37% (117 million kg) and 25% (9 million kg), respectively, and measures to encourage adoption of conservation practices are essential to mitigate water quality impairments. Dried distiller's grains remaining after ethanol production from corn grain are used as animal feed and can increase manure P content and may increase N content. Cellulosic fuel‐stocks from perennials such as switchgrass and woody materials have the potential to produce ethanol. Although production, storage, and handling of cellulosic materials and conversion technology are limitations, accelerating development of cellulosic ethanol has the potential to reduce dependence on grain fuel‐stocks and provide water quality and other environmental benefits. All alternative fuel production technologies could have environmental impacts. There is a need to understand these impacts to help guide policy and help make programmatic and scientific decisions that avoid or mitigate unintended environmental consequences of biofuel production.
Disparities in Cardiovascular Disease Risk and Treatment
Authors: Colleran Kathleen M. , Richards Allyson , Shafer Keri 
Published: February 2008

Background Cardiovascular morbidity and mortality can be prevented by identification and modification of specific risk factors. Ethnic minorities have a higher incidence of cardiovascular risk factors. Additionally, ethnic minorities often reside in medically underserved areas and are subject to health care disparities. We hypothesized that ethnic minorities residing in medically underserved areas would experience greater health care disparities related to cardiovascular disease (CVD) prevention and treatment compared with those residing near an urban academic medical center. Methods We performed a retrospective chart review ( N = 200) comparing an urban academic medical center with a rural community center. We evaluated the effects of ethnicity, demographics, and the absence or presence of CVD on cardiovascular risk factor prevalence, risk factor reduction, and CVD prevention and treatment. Results We found that Hispanics had more cardiovascular risk factors, including diabetes mellitus and low high-density lipoprotein cholesterol, compared with non-Hispanic whites. However, there were no ethnically based differences in risk factor prevalence by location. Additionally, ethnicity had no impact on the management of cardiovascular risk factors. However, patients with CVD residing in the rural location, regardless of ethnicity, received significantly fewer secondary prevention treatments compared with patients residing near the urban academic medical center, including aspirin or antiplatelets ( p < .0001); beta-blockers or calcium channel blockers ( p ≤ .0001); diuretics, angiotensin-converting enzyme inhibitors, or angiotensin receptor blockers ( p = .014); and statins ( p ≤ .0001). Conclusions Hispanics have more CVD risk factors than non-Hispanic whites but receive equivalent prevention initiatives. Residing in a rural, medically underserved area, regardless of ethnicity, was associated with the largest CVD treatment and health care disparity.
STAT3 Sensitizes Insulin Signaling by Negatively Regulating Glycogen Synthase Kinase-3β
Authors: Moh Akira , Zhang Wenjun , Yu Sidney , Wang Jun , Xu Xuming , Li Jiliang , Fu Xin-Yuan 
Published: February 2008

OBJECTIVE— Glucose homeostasis is achieved by triggering regulation of glycogen synthesis genes in response to insulin when mammals feed, but the underlying molecular mechanism remains largely unknown. The aim of our study was to examine the role of the signal transducers and activators of transcription 3 (STAT3) in insulin signaling.
RESEARCH DESIGN AND METHODS— We generated a strain of mice carrying a targeted disruption of Stat3 gene in the liver (L-Stat3−/− mice). Hepatocytes of the L-Stat3−/− mice were isolated to establish cell lines for mechanistic studies. Nuclear translocation and DNA-protein interaction of STAT3 was analyzed with immunofluorescent and chromatin immunoprecipitation methods, respectively. Levels of glucose, insulin, leptin, and glucagon were profiled, and putative downstream molecules of STAT3 were examined in the presence of various stimuli in L-Stat3−/− and control mice.
RESULTS— STAT3 was found to sensitize the insulin signaling through suppression of GSK-3β, a negative regulator of insulin signaling pathway. During feeding, both mRNA and protein levels of GSK-3β decreased in Stat3f/+ mice, which reflected the need of hepatocytes for insulin to induce glycogen synthesis. In contrast, the L-Stat3−/− mice lost this control and showed a monophasic increase in the GSK-3β level in response to insulin. Administration of GSK-3β inhibitors lithium chloride and L803-mts restored glucose homeostasis and rescued the glucose intolerance and impaired insulin response in L-Stat3−/− mice.
CONCLUSIONS— These data indicate that STAT3 sensitizes insulin signaling by negatively regulating GSK-3β. Inactivation of STAT3 in the liver contributes significantly to the pathogenesis of insulin resistance.
Selective Activation of Peroxisome Proliferator–Activated Receptor (PPAR)α and PPARγ Induces Neoangiogenesis Through a Vascular Endothelial Growth Factor–Dependent Mechanism
Authors: Biscetti Federico , Gaetani Eleonora , Flex Andrea , Aprahamian Tamar , Hopkins Teresa , Straface Giuseppe , Pecorini Giovanni , Stigliano Egidio , Smith Roy C. , Angelini Flavia , Castellot John J. , Pola Roberto 
Published: February 2008

OBJECTIVE—Peroxisome proliferator–activated receptors (PPARs) are therapeutic targets for fibrates and thiazolidinediones, which are commonly used to ameliorate hyperlipidemia and hyperglycemia in type 2 diabetes. In this study, we evaluated whether activation of PPARα and PPARγ stimulates neoangiogenesis.
RESEARCH DESIGN AND METHODS—We used selective synthetic PPARα and PPARγ agonists and investigated their angiogenic potentials in vitro and in vivo.
RESULTS—Activation of PPARα and PPARγ leads to endothelial tube formation in an endothelial/interstitial cell co-culture assay. This effect is associated with increased production of the angiogenic cytokine vascular endothelial growth factor (VEGF). Neovascularization also occurs in vivo, when PPARα and PPARγ agonists are used in the murine corneal angiogenic model. No vascular growth is detectable when PPARα and PPARγ agonists are respectively used in PPARα knockout mice and mice treated with a specific PPARγ inhibitor, demonstrating that this angiogenic response is PPAR mediated. PPARα- and PPARγ-induced angiogenesis is associated with local VEGF production and does not differ in extent and morphology from that induced by VEGF. In addition, PPARα- and PPARγ-induced in vitro and in vivo angiogenesis may be significantly decreased by inhibiting VEGF activity. Finally, in corneas treated with PPARα and PPARγ agonists, there is increased phosphorylation of endothelial nitric oxide synthase and Akt.
CONCLUSIONS—These findings demonstrate that PPARα and PPARγ activation stimulates neoangiogenesis through a VEGF-dependent mechanism. Neoangiogenesis is a crucial pathological event in type 2 diabetes. The ability of PPARα and PPARγ agonists to induce neoangiogenesis might have important implications for the clinical and therapeutic management of type 2 diabetes.