Environmental and biogeochemical changes following a decade's reclamation in the Dapeng (Tapong) Bay, southwestern Taiwan

NASA Astrophysics Data System (ADS)

Hung, J.-J.; Huang, W.-C.; Yu, C.-S.

2013-09-01

This study examines the environmental and biogeochemical changes in Dapeng (formerly spelled Tapong) Bay, a semi-enclosed coastal lagoon in southwestern Taiwan, after two major reclamation works performed between 1999 and 2010. The lagoon was largely occupied by oyster culture racks and fish farming cages before December, 2002. Substantial external inputs of nutrients and organic carbon and the fairly long water exchange time (τ) (10 ± 2 days) caused the lagoon to enter a eutrophic state, particularly at the inner lagoon, which directly received nutrient inputs. However, the entire lagoon showed autotrophic, and the estimated net ecosystem production (NEP) during the first stage was 5.8 mol C m-2 yr-1. After January, 2003, the aquaculture structures were completely removed, and the τ decreased to 6 ± 2 days. The annual mean concentrations of dissolved oxygen increased, and nutrients decreased substantially, likely due to improved water exchange, absence of feeding and increased biological utilization. The NEP increased 37% to 7.7 mol C m-2 yr-1 after structure removal. The second reclamation work beginning from July, 2006, focused on establishing artificial wetlands for wastewater treatment and on dredging bottom sediment. Although the τ did not change significantly (8 ± 3 days), substantial decreases in nutrient concentrations and dissolved organic matter continued. The NEP (14.3 mol C m-2 yr-1) increased 85% compared to that in the second stage. The data suggest that the reclamations substantially improved water quality, carbon and nutrient biogeochemical processes and budgets in this semi-enclosed ecosystem.

Effects of elevated carbon dioxide concentrations on broiler chicken performance from 28 to 49 days

USDA-ARS?s Scientific Manuscript database

Improvements in modern broiler housing have substantially reduced air leakage, making proper operation of ventilation systems critical to maintaining a suitable environment. Fuel prices have increased in recent years, leading to reduced minimum ventilation in order to conserve fuel which increases ...

Assessing Provincial PM2.5 Trends in China from 2001 to 2015 Using High-Resolution Satellite Remote Sensing

NASA Astrophysics Data System (ADS)

Lin, C.; Lau, A. K. H.; LI, Y.; Li, C.

2017-12-01

Given the vast territory of China, control efforts for air pollution and the long-term PM2.5 trends may substantially differ among the provinces. In this study, we aim to assess the provincial PM2.5 trends in China during the past few Five-Year Plan (FYP) periods. The lack of long-term PM2.5 measurements, however, makes such assessment difficult. Satellite remote sensing of PM2.5 concentration is an important step toward filling this data gap. In this study, a PM2.5 data set was built over China at a resolution of 1 km from 2001 to 2015 using satellite remote sensing. Analyses show that the national average of PM2.5 concentration increased by 0.11 µg·m-3·yr-1 during the 10th FYP period (2001 to 2005) and started to decline by -0.75 µg·m-3·yr-1 and -2.20 µg·m-3·yr-1 during the 11th (2006 to 2010) and the 12th (2011 to 2015) FYP period, respectively. In addition, substantial differences in the PM2.5 trends were observed among the provinces. Although PM2.5 concentrations remained steady or worsened in most provinces during the 10th FYP period, PM2.5 concentrations substantially declined for provinces in the Beijing-Tianjin-Hebei (BTH) region, suggesting that these provinces were the most successful in their control efforts during this period. The most substantial decline in provincial PM2.5 concentration during the 12th FYP period was also observed in the BTH region. In contrast, PM2.5 concentrations remained steady for provinces in eastern and southeastern China (e.g., Shanghai) during the 12th FYP period, suggesting that these provinces have been less successful in controlling PM2.5 concentrations since 2011 and therefore require more efforts to effectively reduce the PM2.5 concentrations in future.

Urban sprawl leaves its PAH signature

USGS Publications Warehouse

Van Metre, P.C.; Mahler, B.J.; Furlong, E.T.

2000-01-01

The increasing vehicle traffic associated with urban sprawl in the United States is frequently linked to degradation of air quality, but its effect on aquatic sediment is less well-recognized. This study evaluates trends in PAHs, a group of contaminants with multiple urban sources, in sediment cores from 10 reservoirs and lakes in six U.S. metropolitan areas. The watersheds chosen represent a range in degree and age of urbanization. Concentrations of PAHs in all 10 reservoirs and lakes increased during the past 20-40 years. PAH contamination of the most recently deposited sediment at all sites exceeded sediment-quality guidelines established by Environment Canada, in some cases by several orders of magnitude. These results add a new chapter to the story told by previous coring studies that reported decreasing concentrations of PAHs after reaching highs in the 1950s. Concurrent with the increase in concentrations is a change in the assemblage of PAHs that indicates the increasing trends are driven by combustion sources. The increase in PAH concentrations tracks closely with increases in automobile use, even in watersheds that have not undergone substantial changes in urban land-use levels since the 1970s.The increasing vehicle traffic associated with urban sprawl in the United States is frequently linked to degradation of air quality, but its effect on aquatic sediment is less well-recognized. This study evaluates trends in PAHs, a group of contaminants with multiple urban sources, in sediment cores from 10 reservoirs and lakes in six U.S. metropolitan areas. The watersheds chosen represent a range in degree and age of urbanization. Concentrations of PAHs in all 10 reservoirs and lakes increased during the past 20-40 years. PAH contamination of the most recently deposited sediment at all sites exceeded sediment-quality guidelines established by Environment Canada, in some cases by several orders of magnitude. These results add a new chapter to the story told by previous coring studies that reported decreasing concentrations of PAHs after reaching highs in the 1950s. Concurrent with the increase in concentrations is a change in the assemblage of PAHs that indicates the increasing trends are driven by combustion sources. The increase in PAH concentrations tracks closely with increases in automobile use, even in watersheds that have not undergone substantial changes in urban land-use levels since the 1970s.

Recovery of Active and Efficient Photocatalytic H 2 Production for CdSe Quantum Dots

DOE PAGES

Burke, Rebeckah; Cogan, Nicole M. Briglio; Oi, Aidan; ...

2018-05-07

Recently, colloidal semiconductor quantum dots (QDs) have shown great promise as photocatalysts for the production of chemical fuels by sunlight. Here, the efficiency of photocatalytic hydrogen (H 2) production for integrated systems of large diameter (4.4 nm) CdSe QDs as light harvesting nanoparticles with varying concentrations of nickel-dihydrolipoic acid (Ni-DHLA) small molecule catalysts was measured. While exhibiting excellent robustness and longevity, the efficiency of H 2 production for equimolar catalyst and QDs was relatively poor. However, the efficiency was found to increase substantially with increasing Ni-DHLA:QD molar ratios Surprisingly, this high activity was only observed with the use of 3-mercaptopropionicmore » acid (MPA) ligands, while CdSe QDs capped with dihydrolipoic acid (DHLA) exhibited poor performance in comparison, indicating that the QD capping ligand has a substantial impact on the catalytic performance. Finally, ultrafast transient absorption spectroscopic measurements of the electron transfer (ET) dynamics show fast ET to the catalyst. Importantly, an increase in ET efficiency is observed as the catalyst concentration is increased. Together, these results suggest that for these large QDs, tailoring the QD surface environment for facile ET and increasing catalyst concentrations increases the probability of ET from QDs to Ni-DHLA, overcoming the relatively small driving force for ET and decreased surface electron density for large diameter QDs.« less

Recovery of Active and Efficient Photocatalytic H 2 Production for CdSe Quantum Dots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burke, Rebeckah; Cogan, Nicole M. Briglio; Oi, Aidan

Recently, colloidal semiconductor quantum dots (QDs) have shown great promise as photocatalysts for the production of chemical fuels by sunlight. Here, the efficiency of photocatalytic hydrogen (H 2) production for integrated systems of large diameter (4.4 nm) CdSe QDs as light harvesting nanoparticles with varying concentrations of nickel-dihydrolipoic acid (Ni-DHLA) small molecule catalysts was measured. While exhibiting excellent robustness and longevity, the efficiency of H 2 production for equimolar catalyst and QDs was relatively poor. However, the efficiency was found to increase substantially with increasing Ni-DHLA:QD molar ratios Surprisingly, this high activity was only observed with the use of 3-mercaptopropionicmore » acid (MPA) ligands, while CdSe QDs capped with dihydrolipoic acid (DHLA) exhibited poor performance in comparison, indicating that the QD capping ligand has a substantial impact on the catalytic performance. Finally, ultrafast transient absorption spectroscopic measurements of the electron transfer (ET) dynamics show fast ET to the catalyst. Importantly, an increase in ET efficiency is observed as the catalyst concentration is increased. Together, these results suggest that for these large QDs, tailoring the QD surface environment for facile ET and increasing catalyst concentrations increases the probability of ET from QDs to Ni-DHLA, overcoming the relatively small driving force for ET and decreased surface electron density for large diameter QDs.« less

Normalization of urinary drug concentrations with specific gravity and creatinine.

PubMed

Cone, Edward J; Caplan, Yale H; Moser, Frank; Robert, Tim; Shelby, Melinda K; Black, David L

2009-01-01

Excessive fluid intake can substantially dilute urinary drug concentrations and result in false-negative reports for drug users. Methods for correction ("normalization") of drug/metabolite concentrations in urine have been utilized by anti-doping laboratories, pain monitoring programs, and in environmental monitoring programs to compensate for excessive hydration, but such procedures have not been used routinely in workplace, legal, and treatment settings. We evaluated two drug normalization procedures based on specific gravity and creatinine. These corrections were applied to urine specimens collected from three distinct groups (pain patients, heroin users, and marijuana/ cocaine users). Each group was unique in characteristics, study design, and dosing conditions. The results of the two normalization procedures were highly correlated (r=0.94; range, 0.78-0.99). Increases in percent positives by specific gravity and creatinine normalization were small (0.3% and -1.0%, respectively) for heroin users (normally hydrated subjects), modest (4.2-9.8%) for pain patients (unknown hydration state), and substantial (2- to 38-fold increases) for marijuana/cocaine users (excessively hydrated subjects). Despite some limitations, these normalization procedures provide alternative means of dealing with highly dilute, dilute, and concentrated urine specimens. Drug/metabolite concentration normalization by these procedures is recommended for urine testing programs, especially as a means of coping with dilute specimens.

River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons

USGS Publications Warehouse

Corsi, Steven R.; De Cicco, Laura A.; Lutz, Michelle A.; Hirsch, Robert M.

2014-01-01

Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006–2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period.

River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons.

PubMed

Corsi, Steven R; De Cicco, Laura A; Lutz, Michelle A; Hirsch, Robert M

2015-03-01

Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006-2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period. Published by Elsevier B.V.

Postprandial plasma betaine and other methyl donor-related responses after consumption of minimally processed wheat bran or wheat aleurone, or wheat aleurone incorporated into bread.

PubMed

Keaveney, Edel M; Price, Ruth K; Hamill, Lesley L; Wallace, Julie M W; McNulty, Helene; Ward, Mary; Strain, J J; Ueland, Per M; Molloy, Anne M; Piironen, Vieno; von Reding, Walter; Shewry, Peter R; Ward, Jane L; Welch, Robert W

2015-02-14

The bran and particularly the aleurone fraction of wheat are high in betaine and other physiological methyl donors, which may exert beneficial physiological effects. We conducted two randomised, controlled, cross-over postprandial studies to assess and compare plasma betaine and other methyl donor-related responses following the consumption of minimally processed bran and aleurone fractions (study A) and aleurone bread (study B). For both studies, standard pharmacokinetic parameters were derived for betaine, choline, folate, dimethylglycine (DMG), total homocysteine and methionine from plasma samples taken at 0, 0·5, 1, 2 and 3 h. In study A (n 14), plasma betaine concentrations were significantly and substantially elevated from 0·5 to 3 h following the consumption of both bran and aleurone compared with the control; however, aleurone gave significantly higher responses than bran. Small, but significant, increases were also observed in DMG measures; however, no significant responses were observed in other analytes. In study B (n 13), plasma betaine concentrations were significantly and substantially higher following consumption of the aleurone bread compared with the control bread; small, but significant, increases were also observed in DMG and folate measures in response to consumption of the aleurone bread; however, no significant responses were observed in other analytes. Peak plasma betaine concentrations, which were 1·7-1·8 times the baseline levels, were attained earlier following the consumption of minimally processed aleurone compared with the aleurone bread (time taken to reach peak concentration 1·2 v. 2·1 h). These results showed that the consumption of minimally processed wheat bran, and particularly the aleurone fraction, yielded substantial postprandial increases in plasma betaine concentrations. Furthermore, these effects appear to be maintained when aleurone was incorporated into bread.

[Evaluation of influence of diet content and its supplementation with chosen group of B vitamins on lipids and lipoprtoteins concentration in female rat serum].

PubMed

Friedrich, Mariola; Goluch-Koniuszy, Zuzanna

2009-01-01

The influence of diet content and its supplementation with chosen group of B vitamins on the intake of feeding stuff increase, changes of body mass, accumulation of fat tissue, lipids and lipoproteins concentration in the blood of female rats were under research. The animals, aged 5 months, were divided into three groups (8 persons each) and fed ad libitum with granulated Labofeed B type mix. Group I with the basic mix containing among other things whole grain, Group II with a modified mix, where whole grain was replaced by wheat flour and saccharose and Group III with modified mix supplemented in excess with chosen vitamins of B group. This experiment took 6 weeks during which the amount of consumed feed was currently evaluated, and the body mass was controlled weekly. After finishing the experiment in the obtained serum the concentration of triacylglycerols, complete cholesterol with enzyme method and the content of cholesterol fractions with electrophoretic separation method were determined. Analysis of fat content in muscles and livers was conducted and the amount of round the bodily organ fat was determined. It was ascertained that change of the content of the feed and its supplementation with the chosen B group vitamins did not influence in a substantial way its intake and the increase of body mass, however it had influenced substantially, in animals fed with the modified feed the accumulation of round the organ fat and in supplemented the intramuscular fat. Analysis of the results enabled the ascertainment that the diet supplementation with chosen ingredients of the B group vitamins corrects the negative effect of accumulation of the visceral fat tissue as a result of the change of its contents, caused substantial increase in the concentration of triacylglycerols, complete cholesterol and its fractions VLDL- and LDL- with simultaneous decrease of the concentration of cholesterol HDL- fractions.

DC corona discharge ozone production enhanced by magnetic field

NASA Astrophysics Data System (ADS)

Pekárek, S.

2010-01-01

We have studied the effect of a stationary magnetic field on the production of ozone from air at atmospheric pressure by a negative corona discharge in a cylindrical electrode configuration. We used a stainless steel hollow needle placed at the axis of the cylindrical discharge chamber as a cathode. The outer wall of the cylinder was used as an anode. The vector of magnetic induction was perpendicular to the vector of current density. We found that: (a) the magnetic field extends the current voltage range of the discharge; (b) for the discharge in the Trichel pulses regime and in the pulseless glow regime, the magnetic field has no substantial effect on the discharge voltage or on the concentration of ozone that is produced; (c) for the discharge in the filamentary streamer regime for a particular current, the magnetic field increases the discharge voltage and consequently an approximately 30% higher ozone concentration can be obtained; (d) the magnetic field does not substantially increase the maximum ozone production yield. A major advantage of using a magnetic field is that the increase in ozone concentration produced by the discharge can be obtained without additional energy requirements.

Selected natural attenuation monitoring data, Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, June 2002

USGS Publications Warehouse

Dinicola, Richard S.

2004-01-01

Previous investigations indicated that natural attenuation and biodegradation of chlorinated volatile organic compounds (CVOCs) are substantial in shallow ground water beneath the 9-acre former landfill at Operable Unit 1 (OU 1), Naval Undersea Warfare Center (NUWC), Division Keyport, Washington. The U.S. Geological Survey (USGS) has continued to monitor ground-water geochemistry to assure that conditions remain favorable for contaminant biodegradation. This report presents the geochemical and selected CVOC data for ground water at OU 1, collected by the USGS during June 10-14, 2002, in support of long-term monitoring for natural attenuation. Overall, the geochemical data for June 2002 indicate that redox conditions in the upper-aquifer water remain favorable for reductive dechlorination of chlorinated VOCs because strongly reducing conditions persisted beneath much of the former landfill. Redox conditions in the intermediate aquifer downgradient of the landfill also remained favorable for reductive dechlorination, although the 2002 dissolved hydrogen (H2) concentration from well MW1-28 is questionable. Changes in redox conditions were observed at certain wells during 2002, but a longer monitoring period and more thorough interpretation are needed to ascertain if phytoremediation activities are affecting redox conditions and if biodegradation processes are changing over time. The Navy intends to complete a more thorough interpretation in preparation for the 5-year review of OU 1 scheduled for 2004. There were a few substantial differences between the 2002 concentrations and previously observed concentrations of volatile organic compounds. Total CVOC concentrations in 2002 samples decreased substantially in all piezometers sampled in the northern plantation, and the largest percentages of decrease were for the compounds trichloroethene (TCE) and cis-1,2-dichloroethene (cis-DCE). Changes in total CVOC concentrations in the southern plantation were less consistent. Historically high concentrations were observed in samples from three piezometers, with particularly substantial increases in TCE and cis-DCE concentrations, and historically low concentrations were observed in two piezometers, with particularly substantial decreases in TCE and cis-DCE concentrations. Similarly to the redox chemistry, a longer monitoring period and more thorough interpretation are needed to ascertain if phytoremediation activities are affecting CVOC concentrations and if biodegradation processes are changing over time. No changes in monitoring plans are proposed for June 2003, although the practice of deploying a data sonde downhole while purging the wells will be discontinued. Downhole monitoring added uncertainty to selected measured dissolved H2 concentrations because of the possibility that the sonde and cable created a bridge that resulted in non-equilibrium dissolved H2 concentrations at the wells.

Seasonality of diel cycles of dissolved trace-metal concentrations in a Rocky Mountain stream

USGS Publications Warehouse

Nimick, D.A.; Cleasby, T.E.; McCleskey, R. Blaine

2005-01-01

Substantial diel (24-h) cycles in dissolved (0.1-??m filtration) metal concentrations were observed during summer low flow, winter low flow, and snowmelt runoff in Prickly Pear Creek, Montana. During seven diel sampling episodes lasting 34-61.5 h, dissolved Mn and Zn concentrations increased from afternoon minimum values to maximum values shortly after sunrise. Dissolved As concentrations exhibited the inverse timing. The magnitude of diel concentration increases varied in the range 17-152% for Mn and 70-500% for Zn. Diel increases of As concentrations (17-55%) were less variable. The timing of minimum and maximum values of diel streamflow cycles was inconsistent among sampling episodes and had little relation to the timing of metal concentration cycles, suggesting that geochemical rather than hydrological processes are the primary control of diel metal cycles. Diel cycles of dissolved metal concentrations should be assumed to occur at any time of year in any stream with dissolved metals and neutral to alkaline pH. ?? Springer-Verlag 2005.

Forests and water

Treesearch

Graeme Lockaby; Chelsea Nagy; James M. Vose; Chelcy R. Ford; Ge Sun; Steve McNulty; Pete Caldwell; Erika Cohen; Jennifer Moore Myers

2013-01-01

Key FindingsForest conversion to agriculture or urban use consistently causes increased discharge, peak flow, and velocity of streams. Subregional differences in hydrologic responses to urbanization are substantial.Sediment, water chemistry indices, pathogens, and other substances often become more concentrated after forest...

Sodium-dependent magnesium uptake by ferret red cells.

PubMed Central

Flatman, P W; Smith, L M

1991-01-01

1. Magnesium uptake can be measured in ferret red cells incubated in media containing more than 1 mM-magnesium. Uptake is substantially increased if the sodium concentration in the medium is reduced. 2. Magnesium uptake is half-maximally activated by 0.37 mM-external magnesium when the external sodium concentration is 5 mM. Increasing the external sodium concentration increases the magnesium concentration needed to activate the system. 3. Magnesium uptake is increased by reducing the external sodium concentration. Uptake is half-maximum at sodium concentrations of 17, 22 and 62 nM when the external magnesium concentrations are 2, 5 and 10 mM respectively. 4. Replacement of external sodium with choline does not affect the membrane potential of ferret red cells over a 45 min period. 5. Magnesium uptake from media containing 5 mM-sodium is inhibited by amiloride, quinidine and imipramine. It is not affected by ouabain or bumetanide. Vanadate stimulates magnesium uptake but has no effect on magnesium efflux. 6. When cell ATP content is reduced to 19 mumol (1 cell)-1 by incubating cells for 3 h with 2-deoxyglucose, magnesium uptake falls by 50% in the presence of 5 mM-sodium and is completely abolished in the presence of 145 mM-sodium. Some of the inhibition may be due to the increase in intracellular ionized magnesium concentration ([Mg2+]i) from 0.7 to 1.0 mM which occurs under these conditions. 7. Magnesium uptake can be driven against a substantial electrochemical gradient if the external sodium concentration is reduced sufficiently. 8. These findings are discussed in terms of several possible models for magnesium transport. It is concluded that the majority of magnesium uptake observed in low-sodium media is via sodium-magnesium antiport. A small portion of uptake is through a parallel leak pathway. It is believed that the antiport is responsible for maintaining [Mg2+]i below electrochemical equilibrium in these cells at physiological external sodium concentration. Thus in ferret red cells the direction of magnesium transport can be reversed by reversing the sodium gradient. PMID:1822527

Occurrence and Trends of Selected Chemical Constituents in Bottom Sediment, Grand Lake O' the Cherokees, Northeast Oklahoma, 1940-2008

USGS Publications Warehouse

Juracek, Kyle E.; Becker, Mark F.

2009-01-01

After over 100 years of continuous activity, lead and zinc mining in the Tri-State Mining District (hereafter referred to as the TSMD) in parts of southeast Kansas, southwest Missouri, and northeast Oklahoma ended in the 1970s. The mining activity resulted in substantial historical and ongoing input of cadmium, lead, and zinc to the environment including Grand Lake O' the Cherokees (hereafter referred to as Grand Lake), a large reservoir in northeast Oklahoma. To help determine the extent and magnitude of contamination in Grand Lake, a one-year study was conducted by the U.S. Geological Survey in cooperation with the U.S. Fish and Wildlife Service. Bottom-sediment coring at five sites was used to investigate the occurrence of cadmium, lead, zinc, and other selected constituents in the bottom sediment of Grand Lake. Cadmium concentrations in the bottom sediment of Grand Lake ranged from 2.3 to 3.6 mg/kg (milligrams per kilogram) with a median of 3.5 mg/kg (5 samples). Compared to an estimated local background concentration of 0.6 mg/kg, the historical mining activity increased cadmium concentrations by about 280 to 500 percent. Lead concentrations ranged from 35 to 102 mg/kg with a median of 59 mg/kg (50 samples). Compared to an estimated local background concentration of 20 mg/kg, the historical mining activity increased lead concentrations by about 75 to 410 percent. The range in zinc concentrations was 380 to 986 mg/kg with a median of 765 mg/kg (50 samples). Compared to an estimated local background concentration of 100 mg/kg, the historical mining activity increased zinc concentrations by about 280 to 890 percent. With the exception of the most upstream coring site, the lead and zinc depositional profiles generally were similar in terms of the range in concentrations measured and the temporal pattern observed. Depositional profiles for lead and zinc indicated mid-core peaks followed by concentrations that decreased since about the 1980s. The depositional profiles reflect the complex interaction of several factors including historical mining and related activities, mine drainage, remediation, landscape stabilization, precipitation and associated runoff, and the erosion and transport of contaminated and clean sediments within the basin. Compared to sediment-quality guidelines, the Grand Lake samples had cadmium concentrations that were substantially less than the general probable-effects concentration (PEC) (4.98 mg/kg) and a TSMD-specific PEC (11.1 mg/kg). The PECs represent the concentration above which toxic biological effects are likely to occur. Likewise, all sediment samples had lead concentrations that were substantially less than the general PEC (128 mg/kg) and a TSMD-specific PEC (150 mg/kg). Zinc concentrations typically exceeded the general PEC (459 mg/kg), but were substantially less than a TSMD-specific PEC (2,083 mg/kg). Throughout the history of Grand Lake, lead and zinc concentrations in the deposited sediment did not approach or exceed the TSMD-specific PECs. As of 2008, legacy effects of mining still included the delivery of contaminated sediment to Grand Lake by the Spring and Neosho Rivers. The Neosho River, with its larger flows and less-contaminated sediment, likely dilutes the load of contaminated sediment delivered to Grand Lake by the Spring River. The information contained in this report provides a baseline of Grand Lake conditions with which to compare future conditions that may represent a response to changes in mining-related activity in the Grand Lake Basin.

Breakfast frequency and quality may affect glycemia and appetite in adults and children

USDA-ARS?s Scientific Manuscript database

Substantial evidence relates increased sex hormone concentrations with increased breast cancer risk. Varying omega-3 fatty acid (n-3) intake may lead to alterations in eicosanoid balance and subsequent changes in circulating sex hormones that reduce risk. To clarify effects of dietary fat and n-3 i...

Influence of solar radiation on DOM release from resuspended Florida Bay sediments

NASA Astrophysics Data System (ADS)

Shank, G. C.; Evans, A.; Jaffé, R.; Yamashita, Y.

2009-12-01

This study investigated dissolved organic matter (DOM) release from resuspended Florida Bay sediments under dark and sunlit conditions. Much of Florida Bay (located between Everglades and Florida Keys) is very shallow (< 2 m) so sediment resuspension events have the potential to substantially impact the concentration and composition of DOM in the water column. For our study, sediments were collected at several sites across Florida Bay and ranged from 3-11 percent organic carbon (by weight). Sediments were resuspended in oligotrophic seawater for 48 hours in 1 L quartz flasks in the dark and under simulated solar radiation (SunTest XLS+) at concentrations of 100 mg L-1 and 1 g L-1 (wet weight). Final solutions were analyzed for DOC, chromophoric dissolved organic matter (CDOM), and Excitation Emission Matrix (EEM) fluorescence. Results showed little to no DOC increases in the resuspensions performed under dark conditions, but substantial release of DOM in irradiated resuspensions, especially at high sediment concentrations where DOC increases ranged from 100-500%. The sediments also released substantial quantities of CDOM to solution under irradiated conditions. The magnitude of DOC increases in irradiated resuspensions were well-correlated with the amount of particulate organic carbon (POC) added. Data from EEM-PARAFAC analyses suggests the photochemically produced DOM was comprised of desorbed humic material with a smaller fraction from microbial mediated processes. Our study provides evidence that sediment resuspension episodes in shallow sunlit waters such as Florida Bay have the potential to provide an important source of organic carbon to overlying waters.

Effects of drill cuttings on larvae of the cold-water coral Lophelia pertusa

NASA Astrophysics Data System (ADS)

Järnegren, Johanna; Brooke, Sandra; Jensen, Henrik

2017-03-01

Fossil fuel consumption is predicted to dominate energy needs until at least 2040. To make up for reduced production from maturing fields, oil and gas exploration activities on the Norwegian continental shelf have greatly increased over the past several years. Strict emission controls have resulted in a substantial reduction in the release of hazardous chemicals. However, because of the increased exploration the discharges of water-based drill cuttings and muds have increased substantially, temporarily increasing water column sediment loads. The stony coral Lophelia pertusa is the most widely distributed and well-studied of the structure forming cold water corals (CWC) and it thrives in Norwegian waters where many reefs are located in the vicinity of oil platforms or exploration areas. This species provides habitat for a diverse and abundant assemblage of invertebrates and fishes, including commercially valuable species. High sediment loads are known to negatively affect adult corals, but impacts on the early life history stages are unknown. We investigated the effects of a range of drill cutting concentrations (0.5-640 ppm) on larvae of L. pertusa at ages five days and 15-20 days. One set of experiments was conducted in static experimental chambers that exposed larvae to decreasing concentrations over time, and the other maintained continuous drill cutting concentrations for the duration of the experiment (24 h). Increased sediment load for a duration of 24 h caused significant larval mortality, but there was an age-dependent difference in sensitivity of larvae. Younger larvae were significantly more susceptible to lower concentrations of drill cuttings than older larvae, while the older larvae were significantly more affected at higher concentrations. Five day old larvae were affected at treatment concentration 40 ppm. The larval cilia became clogged, preventing the larvae from swimming actively and ultimately causing mortality. Larvae of many species use cilia for swimming and feeding, so negative impacts of increased sediment may not be limited to corals.

Occurrence of pesticides in groundwater underlying areas of high-density row-crop production in Alabama, 2009-2013

USGS Publications Warehouse

Welch, Heather L.

2015-01-01

Concentrations of metolachlor and atrazine have substantially decreased in the northern Alabama wells since 2000. A decline in use of metolachlor and atrazine from a high in the late-1990s and a high in 2004, respectively, in northern Alabama could account for the lower concentrations. Fluometuron use has also declined since 1998, but the relation between time and concentrations differed in the five northern Alabama wells. Fluometuron concentrations in three of the five wells have been decreasing over time, while concentrations in the remaining two wells have been increasing.

Role of Concentrating Solar Power in Integrating Solar and Wind Energy: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, P.; Mehos, M.

2015-06-03

As wind and solar photovoltaics (PV) increase in penetration it is increasingly important to examine enabling technologies that can help integrate these resources at large scale. Concentrating solar power (CSP) when deployed with thermal energy storage (TES) can provide multiple services that can help integrate variable generation (VG) resources such as wind and PV. CSP with TES can provide firm, highly flexible capacity, reducing minimum generation constraints which limit penetration and results in curtailment. By acting as an enabling technology, CSP can complement PV and wind, substantially increasing their penetration in locations with adequate solar resource.

Effects of Copper Pollution on the Phenolic Compound Content, Color, and Antioxidant Activity of Wine.

PubMed

Sun, Xiangyu; Ma, Tingting; Han, Luyang; Huang, Weidong; Zhan, Jicheng

2017-05-03

The effects of copper pollution on the polyphenol content, color, and antioxidant activity of wine, as well as correlations among these factors, were investigated. Copper had clear influences on wine polyphenol content. At low copper concentrations, the concentrations of nearly all polyphenols increased, and the antioxidant activity values of the wine also increased. When the copper concentration reached the lowest level of the medium copper range (9.6~16 mg/L), most of the indices also improved. When the copper concentrations reached the latter part of the medium copper range (19.2 and 22.4 mg/L), many of the tested indices began to decrease. Furthermore, when the copper concentration reached the high ranges (32, 64, and 96 mg/L), the polyphenol content, CIELAB color parameters, and antioxidant activity of wine were substantially decreased, indicating the need to control increasing copper content in grape must.

Hospital prices and market structure in the hospital and insurance industries.

PubMed

Moriya, Asako S; Vogt, William B; Gaynor, Martin

2010-10-01

There has been substantial consolidation among health insurers and hospitals, recently, raising questions about the effects of this consolidation on the exercise of market power. We analyze the relationship between insurer and hospital market concentration and the prices of hospital services. We use a national US dataset containing transaction prices for health care services for over 11 million privately insured Americans. Using three years of panel data, we estimate how insurer and hospital market concentration are related to hospital prices, while controlling for unobserved market effects. We find that increases in insurance market concentration are significantly associated with decreases in hospital prices, whereas increases in hospital concentration are non-significantly associated with increases in prices. A hypothetical merger between two of five equally sized insurers is estimated to decrease hospital prices by 6.7%.

Economic Assistance and Security. Rethinking U. S. Policy,

DTIC Science & Technology

1982-01-01

taxation, and community rewards, designed to lower fertility rates, hold possibilities of wider application. Greater use of and research in male ... contraceptive methods and concentration on increasing literacy among young women also have substantial potential for decreasing birth rates. And development

Germination of CO2-enriched Pinus taeda L. seeds and subsequent seedling growth responses to CO2 enrichment

Treesearch

M. Hussain; M. E. Kubiske; K. F. Connor

2001-01-01

Increasing atmospheric carbon dioxide concentration, [CO2], has profound effects on growth and development of trees. Adoubling of [C02] generally stimulates photosynthesis (Murray 1995; Saxe, Ellsworth & Heath 1998) and can lead to a substantial increase in tree growth (Poorter 1993). For example, doubling [C0

Nitrate in aquifers beneath agricultural systems

USGS Publications Warehouse

Burkart, M.R.; Stoner, J.D.

2002-01-01

Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWOA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and shallow carbonate aquifers provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The agricultural system of corn, soybeans, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems, although mean nitrate concentrations in counties with dairy, poultry, cattle and grains, and horticulture systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of this practice.

Pre- and post-impoundment nitrogen in the lower Missouri River

USGS Publications Warehouse

Blevins, Dale W.; Wilkison, Donald H.; Niesen, Shelley L.

2013-01-01

Large water-sample sets collected from 1899 through 1902, 1907, and in the early 1950s allow comparisons of pre-impoundment and post-impoundment (1969 through 2008) nitrogen concentrations in the lower Missouri River. Although urban wastes were not large enough to detectably increase annual loads of total nitrogen at the beginning of the 20th century, carcass waste, stock-yard manure, and untreated human wastes measurably increased ammonia and organic-nitrogen concentrations during low flows. Average total-nitrogen concentrations in both periods were about 2.5 mg/l, but much of the particulate-organic nitrogen, which was the dominant form of nitrogen around 1900, has been replaced by nitrate. This change in speciation was caused by the nearly 80% decrease in suspended-sediment concentrations that occurred after impoundment, modern agriculture, drainage of riparian wetlands, and sewage treatment. Nevertheless, bioavailable nitrogen has not been low enough to limit primary production in the Missouri River since the beginning of the 20th century. Nitrate concentrations have increased more rapidly from 2000 through 2008 (5 to 12% per year), thus increasing bioavailable nitrogen delivered to the Mississippi River and affecting Gulf Coast hypoxia. The increase in nitrate concentrations with distance downstream is much greater during the post-impoundment period. If strategies to decrease total-nitrogen loads focus on particulate N, substantial decreases will be difficult because particulate nitrogen is now only 23% of total nitrogen in the Missouri River. A strategy aimed at decreasing particulates also could further exacerbate land loss along the Gulf of Mexico, which has been sediment starved since Missouri River impoundment. In contrast, strategies or benchmarks aimed at decreasing nitrate loads could substantially decrease nitrogen loadings because nitrates now constitute over half of the Missouri's nitrogen input to the Mississippi. Ongoing restoration and creation of wetlands along the Missouri River could be part of such a nitrate-reduction strategy. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Enhanced PM2.5 pollution in China due to aerosol-cloud interactions.

PubMed

Zhao, Bin; Liou, Kuo-Nan; Gu, Yu; Li, Qinbin; Jiang, Jonathan H; Su, Hui; He, Cenlin; Tseng, Hsien-Liang R; Wang, Shuxiao; Liu, Run; Qi, Ling; Lee, Wei-Liang; Hao, Jiming

2017-06-30

Aerosol-cloud interactions (aerosol indirect effects) play an important role in regional meteorological variations, which could further induce feedback on regional air quality. While the impact of aerosol-cloud interactions on meteorology and climate has been extensively studied, their feedback on air quality remains unclear. Using a fully coupled meteorology-chemistry model, we find that increased aerosol loading due to anthropogenic activities in China substantially increases column cloud droplet number concentration and liquid water path (LWP), which further leads to a reduction in the downward shortwave radiation at surface, surface air temperature and planetary boundary layer (PBL) height. The shallower PBL and accelerated cloud chemistry due to larger LWP in turn enhance the concentrations of particulate matter with diameter less than 2.5 μm (PM 2.5 ) by up to 33.2 μg m -3 (25.1%) and 11.0 μg m -3 (12.5%) in January and July, respectively. Such a positive feedback amplifies the changes in PM 2.5 concentrations, indicating an additional air quality benefit under effective pollution control policies but a penalty for a region with a deterioration in PM 2.5 pollution. Additionally, we show that the cloud processing of aerosols, including wet scavenging and cloud chemistry, could also have substantial effects on PM 2.5 concentrations.

Investigation of Artificial Forced Cooling in the Bridgman Crystal Growth of Cadmium Zinc Telluride

NASA Astrophysics Data System (ADS)

Liu, Juncheng; Li, Jiao; Zhang, Guodong; Li, Changxing; Lennon, Craig; Sivananthan, Siva

2007-08-01

The effects of artificial forced cooling on the solid liquid interface and on solute segregation were investigated by modeling the vertical Bridgman method for the single-crystal growth of CdZnTe, taking into consideration effects such as increasing the axial outward heat flux from the crucible bottom, the radial outward heat flux from the crucible wall, and the carbon film thickness on the crucible inner wall. Axial artificially forced cooling noticeably increases convection and the temperature gradient in the melt next to the solid liquid interface, and substantially reduces interface concavity at the initial solidification stage. Interface concavity increases a little when the solidification proceeds further, however. Axial artificially forced cooling reduces radial solute segregation of the initial segment of the grown crystal and slightly increases the solute iso-concentration segment. Radial artificially forced cooling enhances melt convection substantially, affects solid liquid interface concavity only slightly, and hardly affects solute segregation in the grown crystal. Doubling the carbon film thickness weakens convection of the melt in front of the interface, substantially increases interface concavity, and hardly affects solute segregation in the grown crystal.

CARBON BALANCE OF THE CONTINUOUS PERMAFROST ZONE OF RUSSIA

EPA Science Inventory

An increase in the atmospheric concentration of CO2 is projected to cause climate warming. arming of the permafrost environment could change the balance between carbon accumulation and decomposition processes and substantially disrupt the equilibrium of the carbon cycle. arming m...

EVALUATING THE EFFECTS OF NEAR ROAD SOLID AND VEGETATION BARRIERS ON MSAT EXPOSURES

EPA Science Inventory

Public health concerns for populations living, working and going to school near high-traffic roadways has increased substantially in recent years. Air quality measurement studies indicate high pollutant concentrations can occur near these large roads, impacting population exposu...

Degradation of paracetamol in aqueous solutions by TiO2 photocatalysis.

PubMed

Yang, Liming; Yu, Liya E; Ray, Madhumita B

2008-07-01

In this study, photo/photocatalytic oxidation of common analgesic and antipyretic drug, paracetamol (acetaminophen), was investigated to determine the optimal operating conditions for degradation in water. UVA (365 nm) radiation alone degraded negligible amount of paracetamol, whereas paracetamol concentration decreased substantially under an irradiation of UVC (254 nm) with marginal changes in total organic carbon (TOC). In the presence of TiO2, much faster photodegradation of paracetamol and effective mineralization occurred; more than 95% of 2.0mM paracetamol was degraded within 80 min. The degradation rate constant decreased with an increase in the initial concentration of paracetamol, while it increased with light intensity and oxygen concentration. The degradation rate also increased with TiO2 loading until a concentration of 0.8 g L(-1). The degradation rate slowly increased between pH 3.5 and 9.5, but significantly decreased with increasing pH between 9.5 and 11.0. Based on the experimental data, a kinetic equation describing paracetamol photocatalytic degradation with various process parameters is obtained.

The landsnail Cepaea nemoralis regulates internal Cd levels when fed on Cd-enriched stinging nettle (Urtica dioica) leaves at low, field-relevant concentrations.

PubMed

Notten, M J M; Oosthoek, A J P; Rozema, J; Aerts, R

2006-01-01

We studied Cd accumulation in Cepaea nemoralis snails at low, but field-relevant Cd concentrations in the diet (Urtica dioica leaves). Six treatments of U. dioica plants were grown, resulting in leaf Cd concentrations between 0 and 2.6 microg g(-1) dw. Seven snails per treatment were fed for 38 days. Leaf Cd concentrations did not affect food consumption rates, and consequently Cd intake rates increased with increasing leaf concentrations. No differences were detected among treatments in the final soft tissue Cd concentrations and body burdens in the snails. Regression analyses showed no positive relationship between either snail Cd concentrations or body burdens and total Cd intake. This suggests a regulation of internal Cd concentrations at low food Cd concentrations. Our data suggest that Cd excretion via the mucus plays a substantial role in this regulation, in addition to Cd excretion via the faeces. Snail shells were no sinks for Cd.

Diel cycles in dissolved metal concentrations in streams: Occurrence and possible causes

USGS Publications Warehouse

Nimick, David A.; Gammons, Christopher H.; Cleasby, Thomas E.; Madison, James P.; Skaar, Don; Brick, Christine M.

2003-01-01

Substantial diel (24‐hour) cycles in dissolved (0.1‐μm filtration) metal concentrations were observed during low flow for 18 sampling episodes at 14 sites on 12 neutral and alkaline streams draining historical mining areas in Montana and Idaho. At some sites, concentrations of Cd, Mn, Ni, and Zn increased as much as 119, 306, 167, and 500%, respectively, from afternoon minimum values to maximum values shortly after sunrise. Arsenic concentrations exhibited the inverse temporal pattern with increases of up to 54%. Variations in Cu concentrations were small and inconsistent. Diel metal cycles are widespread and persistent, occur over a wide range of metal concentrations, and likely are caused primarily by instream geochemical processes. Adsorption is the only process that can explain the inverse temporal patterns of As and the divalent metals. Diel metal cycles have important implications for many types of water‐quality studies and for understanding trace‐metal mobility.

Surface air quality implications of volcanic injection heights

NASA Astrophysics Data System (ADS)

Thomas, Manu Anna; Brännström, Niklas; Persson, Christer; Grahn, Håkan; von Schoenberg, Pontus; Robertson, Lennart

2017-10-01

Air quality implications of volcanic eruptions have gained increased attention recently in association with the 2010 Icelandic eruption that resulted in the shut-down of European air space. The emission amount, injection height and prevailing weather conditions determine the extent of the impact through the spatio-temporal distribution of pollutants. It is often argued that in the case of a major eruption in Iceland, like Laki in 1783-1784, that pollutants injected high into the atmosphere lead to substantially increased concentrations of sulfur compounds over continental Europe via long-range transport in the jet stream and eventual large-scale subsidence in a high-pressure system. Using state-of-the-art simulations, we show that the air quality impact of Icelandic volcanoes is highly sensitive to the injection height. In particular, it is the infinitesimal injections into the lower half of the troposphere, rather than the substantial injections into the upper troposphere/lower stratosphere that contribute most to increased pollutant concentrations, resulting in atmospheric haze over mainland Europe/Scandinavia. Besides, the persistent high pressure system over continental Europe/Scandinavia traps the pollutants from dispersing, thereby prolonging the haze.

Dietary carbohydrates and triacylglycerol metabolism.

PubMed

Roche, H M

1999-02-01

There is a growing body of scientific evidence which demonstrates that plasma triacylglycerol (TAG) concentration, especially in the postprandial state, is an important risk factor in relation to the development of CHD. Postprandial hypertriacylglycerolaemia is associated with a number of adverse metabolic risk factors, including the preponderance of small dense LDL, low HDL-cholesterol concentrations and elevated factor VII activity. Traditionally, a low-fat high-carbohydrate diet was used to prevent CHD because it effectively reduces plasma cholesterol concentrations, but this dietary regimen increases plasma TAG concentrations and reduces HDL-cholesterol concentrations. There is substantial epidemiological evidence which demonstrates that high plasma TAG and low plasma HDL concentrations are associated with an increased risk of CHD. Thus, there is reason for concern that the adverse effects of low-fat high-carbohydrate diets on TAG and HDL may counteract or negate the beneficial effect of reducing LDL-cholesterol concentrations. Although there have been no prospective studies to investigate whether reduced fat intake has an adverse effect on CHD, there is strong epidemiological evidence that reducing total fat intake is not protective against CHD. On the other hand, high-fat diets predispose to obesity, and central obesity adversely affects TAG metabolism. There is substantial evidence that in free-living situations low-fat high-carbohydrate diets lead to weight loss, which in turn will correct insulin resistance and plasma TAG metabolism. Clearly there is a need for prospective studies to resolve the issue as to whether low-fat high-carbohydrate diets play an adverse or beneficial role in relation to the development of CHD.

Dissolved DMSO production via biological and photochemical oxidation of dissolved DMS in the Ross Sea, Antarctica

NASA Astrophysics Data System (ADS)

del Valle, Daniela A.; Kieber, David J.; Toole, Dierdre A.; Bisgrove, John; Kiene, Ronald P.

2009-02-01

Dimethylsulfoxide (DMSO) is an important degradation product of the climate-influencing gas dimethylsulfide (DMS). In the Ross Sea, Antarctica, dissolved DMSO (DMSOd) concentrations exhibited substantial seasonal and vertical variations. Surface water DMSOd concentrations in pre-bloom waters were very low (<1 nM) but increased rapidly up to 41 nM during the spring Phaeocystis antarctica bloom (late November). Increases in DMSOd concentrations lagged by several days increases in DMS concentrations. Although DMSOd concentrations reached relatively high levels during the spring bloom, concentrations were generally higher (36.3-60.6 nM) during summer (January), even though phytoplankton biomass and DMS concentrations had decreased by that time. During both seasons, DMSOd concentrations were substantially higher within the surface mixed layer than below it. DMSOd production from biological DMS consumption (BDMSC) was higher during late November (3.4-5.2 nM d -1) than during the summer (0.7-2.4 nM d -1); therefore, production via BDMSC alone could not explain the higher DMSOd concentrations encountered during the summer. Mixed layer-integrated DMSOd production from BDMSC was 2.5-13.7 times greater than production from dissolved DMS photolysis during the P. antarctica bloom, while photolysis contributed 1.3 times more DMSO than BDMSC before the bloom. The DMSO yield from BDMSC was consistently higher within the upper mixed layer than at depths below. Experimental incubations with water from the mixed layer showed that exposure to full spectrum sunlight for 72 h caused an increase in the DMSO yield whereas exposure to only photosynthetically active radiation did not. This suggests that ultraviolet radiation is a potential factor shifting the fate of biologically consumed DMS toward DMSO. In general, the highest DMSO yields from BDMSC were in samples with slow biological DMS turnover, whereas fast turnover favored sulfate rather than DMSO as a major end-product. This study provides the first detailed information about DMSOd distribution and production in the Ross Sea and points to DMSOd as an important biological and photochemical degradation product of DMS and a major reservoir of methylated sulfur in these polar surface waters.

Enhanced magnetization in VxFe3-xO4 nanoparticles

NASA Astrophysics Data System (ADS)

Pool, V. L.; Kleb, M. T.; Chorney, C. L.; Arenholz, E.; Idzerda, Y. U.

2015-12-01

Nanoparticles of VxFe3-xO4 with up to 33% vanadium doping (x=0 to 1) and a 9 nm diameter are investigated in order to determine the site preference of the vanadium and the magnetic behavior of the nanoparticles. The iron and vanadium L23-edge X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (MCD) spectra are used to identify that vanadium initially substitutes into the tetrahedral iron site as V3+ and that the average iron moment is observed to increase with vanadium concentration up to 12.5% (x=.375). When the vanadium incorporation exceeds 12.5%, the XAS and MCD show that the vanadium begins substituting as V2+ in the octahedral coordination. This coincides with a rapid reduction of the average moment to zero by 25% (x=.75). The frequency-dependent alternating-current magnetic susceptibility (ACMS) displays a substantial increase in blocking temperature with vanadium concentration and indicated substantial variation in the strength of inter-particle interactions.

Volcanic ash in the water column: Physiological impact on the suspension-feeding bivalve Mytilus chilensis.

PubMed

Salas-Yanquin, L P; Navarro, J M; Pechenik, J A; Montory, J A; Chaparro, O R

2018-02-01

Ashes settling into the sea from volcanic explosions expose suspension-feeding species to reduced seston quality. Adults and juveniles of the mussel Mytilus chilensis were exposed for 15days to the phytoplankton Isochrysis galbana together with various concentrations of ashes. We then quantified impact on survival and physiology. Although no individuals died during the experiment, by the end of the study clearance rates and oxygen consumption rates had decreased substantially, and tissue weight of mussels exposed to the highest ash concentrations declined substantially. Gills showed no physical damage, but did show abundant mucus secretion in response to ash particles. Moreover, as the relative proportions of microalgae to ash in the diet decreased, individuals showed increasing preferential ingestion of microalgal particles. Increased ash content in the diet altered physiological rates and activated distinct particle selection with a high production of pseudofeces and high energy costs, with potential long-term consequences. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tethered catalysts for the hydration of carbon dioxide

DOEpatents

Valdez, Carlos A; Satcher, Jr., Joe H; Aines, Roger D; Wong, Sergio E; Baker, Sarah E; Lightstone, Felice C; Stolaroff, Joshuah K

2014-11-04

A system is provided that substantially increases the efficiency of CO.sub.2 capture and removal by positioning a catalyst within an optimal distance from the air-liquid interface. The catalyst is positioned within the layer determined to be the highest concentration of carbon dioxide. A hydrophobic tether is attached to the catalyst and the hydrophobic tether modulates the position of the catalyst within the liquid layer containing the highest concentration of carbon dioxide.

Vitamin C enhances substantially formation of 5-hydroxymethyluracil in cellular DNA.

PubMed

Modrzejewska, Martyna; Gawronski, Maciej; Skonieczna, Magdalena; Zarakowska, Ewelina; Starczak, Marta; Foksinski, Marek; Rzeszowska-Wolny, Joanna; Gackowski, Daniel; Olinski, Ryszard

2016-12-01

The most plausible mechanism behind active demethylation of 5-methylcytosine involves TET proteins which participate in oxidation of 5-methylcytosine to 5-hydroxymethylcytosine; the latter is further oxidized to 5-formylcytosine and 5-carboxycytosine. 5-Hydroxymethyluracil can be also generated from thymine in a TET-catalyzed process. Ascorbate was previously demonstrated to enhance generation of 5-hydroxymethylcytosine in cultured cells. The aim of this study was to determine the levels of the abovementioned TET-mediated oxidation products of 5-methylcytosine and thymine after addition of ascorbate, using an isotope-dilution automated online two-dimensional ultra-performance liquid chromatography with electrospray ionization tandem mass spectrometry. Intracellular concentration of ascorbate was determined by means of ultra-performance liquid chromatography with UV detection. Irrespective of its concentration in culture medium (10-100µM) and inside the cell, ascorbate stimulated a moderate (2- to 3-fold) albeit persistent (up to 96-h) increase in the level of 5-hydroxymethylcytosine. However, exposure of cells to higher concentrations of ascorbate (100µM or 1mM) stimulated a substantial increase in 5-formylcytosine and 5-carboxycytosine levels. Moreover, for the first time we demonstrated a spectacular (up to 18.5-fold) increase in 5-hydroxymethyluracil content what, in turn, suggests that TET enzymes contributed to the presence of the modification in cellular DNA. These findings suggest that physiological concentrations of ascorbate in human serum (10-100µM) are sufficient to maintain a stable level of 5-hydroxymethylcytosine in cellular DNA. However, markedly higher concentrations of ascorbate (ca. 100µM in the cell milieu or ca. 1mM inside the cell) were needed to obtain a sustained increase in 5-formylcytosine, 5-carboxycytosine and 5-hydroxymethyluracil levels. Such feedback to elevated concentrations of ascorbate may reflect adaptation of the cell to environmental conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

Chapter 13: Water and Forests

Treesearch

Graeme Lockaby; Chelsea Nagy; James M. Vose; Chelcy R. Ford; Ge Sun; Steve McNulty; Pete Caldwell; Erika Cohen; Jennifer Moore Meyers

2011-01-01

Forest conversion to agriculture or urban use consistently causes increased discharge, peak flow, and velocity of streams. Subregional differences in hydrologic responses to urbanization are substantial. Sediment, water chemistry indices, pathogens, and other substances often become more concentrated after forest conversion. If the conversion is to an urban use, the...

Staphylococcus aureus but not Listeria monocytogenes adapt to triclosan and adaptation correlates with increased fabI expression and agr deficiency

PubMed Central

2013-01-01

Background The ability of pathogens to adapt to the widely used biocide, triclosan, varies substantially. The purpose of the study was to examine bacterial adaptation over an extended period of time to low increments of triclosan concentrations. Focus was two human pathogens, S. aureus and L. monocytogenes that previously have displayed inherent high and low adaptability, respectively. Results Three strains of L. monocytogenes and two strains of S. aureus including the community-acquired USA300 were exposed to increasing, sub-lethal concentrations of triclosan in triclosan-containing agar gradients. Following 25 days of exposure on agar plates to sub-lethal concentrations of triclosan with a twofold concentration increase every second day, minimum inhibitory concentration (MIC) for S. aureus increased from 0.125 (8325–4) and 0.0625 (USA 300) mg/L to 4 mg/L. The MIC of all three L. monocytogenes strains was initially 4 mg/L and remained unaltered by the exposure. The adapted S. aureus isolates retained normal colony size but displayed increased expression of fabI encoding an essential enzyme in bacterial fatty acid synthesis. Also, they displayed decreased or no expression of the virulence associated agrC of the agr quorum sensing system. While most adapted strains of USA300 carried mutations in fabI, none of the adapted strains of 8325–4 did. Conclusions Adaptability to triclosan varies substantially between Gram positive human pathogens. S. aureus displayed an intrinsically lower MIC for triclosan compared to L. monocytogenes but was easily adapted leading to the same MIC as L. monocytogenes. Even though all adapted S. aureus strains over-expressed fabI and eliminated expression of the agr quorum sensing system, adaptation in USA300 involved fabI mutations whereas this was not the case for 8325–4. Thus, adaptation to triclosan by S. aureus appears to involve multiple genetic pathways. PMID:23898801

Overview of the 1994 chronic HT release experiment at Chalk River

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, P.A.; Workman, W.J.G.; Amiro, B.D.

1995-10-01

Trace amounts of tritiated hydrogen (HT) were released continuously to the atmosphere at Chalk River Laboratories over the 12-day period 1994 July 27 to August 8. Scientists from eight institutions in four countries took extensive air, soil and vegetation samples to study the dynamics of tritiated water (HTO) and organically-bound tritium (OBT) formation, and the environmental concentrations of these compounds at steady-state. The short-term HT air concentrations varied strongly in time and space over the test area, but the variation decreased rapidly as the averaging time increased. HTO concentrations in soil, vegetation and air built up gradually over time butmore » they fluctuated substantially with ambient meteorological conditions, particularly rainfall. OBT concentrations in plants increased throughout the period. HTO concentrations were at or near steady-state at the end of the release, but OBT levels were continuing to rise. 8 refs., 2 figs., 1 tab.« less

Improved COD Measurements for Organic Content in Flowback Water with High Chloride Concentrations.

PubMed

Cardona, Isabel; Park, Ho Il; Lin, Lian-Shin

2016-03-01

An improved method was used to determine chemical oxygen demand (COD) as a measure of organic content in water samples containing high chloride content. A contour plot of COD percent error in the Cl(-)-Cl(-):COD domain showed that COD errors increased with Cl(-):COD. Substantial errors (>10%) could occur in low Cl(-):COD regions (<300) for samples with low (<10 g/L) and high chloride concentrations (>25 g/L). Applying the method to flowback water samples resulted in COD concentrations ranging in 130 to 1060 mg/L, which were substantially lower than the previously reported values for flowback water samples from Marcellus Shale (228 to 21 900 mg/L). It is likely that overestimations of COD in the previous studies occurred as result of chloride interferences. Pretreatment with mercuric sulfate, and use of a low-strength digestion solution, and the contour plot to correct COD measurements are feasible steps to significantly improve the accuracy of COD measurements.

Human exposures to volatile halogenated organic chemicals in indoor and outdoor air.

PubMed Central

Andelman, J B

1985-01-01

Volatile halogenated organic chemicals are found in indoor and outdoor air, often at concentrations substantially above those in remote, unpopulated areas. The outdoor ambient concentrations vary considerably among sampling stations throughout the United States, as well as diurnally and daily. The vapor pressures and air-water equilibrium (Henry's Law) constants of these chemicals influence considerably the likely relative human exposures for the air and water routes. Volatilization of chemicals from indoor uses of water can be a substantial source of exposure, as shown for radon-222. Measurements of air concentrations of trichloroethylene (TCE) in showers using TCE contaminated groundwater show increases with time to as high as one-third of occupational threshold limit values. Using a scaled down experimental shower, such volatilization and subsequent decay in air was also demonstrated. Using a simplified indoor air model and assuming complete volatilization from a full range of typical water uses within the home, calculations indicate that the expected air inhalation exposures can be substantially higher than those from ingestion of these chemicals in drinking water. Although the regulation of toxic chemicals in potable water supplies has focused traditionally on direct ingestion, the volatilization and inhalation from other much greater volume indoor uses of water should be considered as well. PMID:4085436

Linking river nutrient concentrations to land use and rainfall in a paddy agriculture-urban area gradient watershed in southeast China.

PubMed

Xia, Yongqiu; Ti, Chaopu; She, Dongli; Yan, Xiaoyuan

2016-10-01

The effects of land use and land-use changes on river nutrient concentrations are not well understood, especially in the watersheds of developing countries that have a mixed land use of rice paddy fields and developing urban surfaces. Here, we present a three-year study of a paddy agricultural-urban area gradient watershed in southeast China. The annual anthropogenic nitrogen (N) input from the agricultural region to the urban region was high, yet the results showed that the monthly nutrient concentrations in the river were low in the rainy seasons. The nutrient concentrations decreased continuously as the river water passed through the traditional agriculture region (TAR; paddy rice and wheat rotation) and increased substantially in the city region (CR). The traditional agricultural reference region exported most of the nutrient loads at high flows (>1mmd(-1)), the intensified agricultural region (IAR, aquaculture and poultry farming) exported most of the nutrient loads at moderate flows (between 0.5 and 1mmd(-1)), and the CR reference area exported most of the nutrient loads under low to moderate flows. We developed a statistical model to link variations in the nutrient concentrations to the proportion of land-use types and rainfall. The statistical results showed that impervious surfaces, which we interpret as a proxy for urban activities including sewage disposal, were the most important drivers of nutrient concentrations, whereas water surfaces accounted for a substantial proportion of the nutrient sinks. Therefore, to efficiently reduce water pollution, sewage from urban areas must be addressed as a priority, although wetland restoration could also achieve substantial pollutant removal. Copyright © 2016. Published by Elsevier B.V.

An approach to counteracting long-term microgravity-induced muscle atrophy

NASA Technical Reports Server (NTRS)

Tesch, P. A.; Buchanan, P.; Dudley, G. A.

1990-01-01

To find means of alleviating muscle atrophy induced by long-term microgravity, the effects of a 19-week-long heavy-resistance training regime (using either concentric muscle actions only or concentric and eccentric muscle actions) on the strengths of the exercised knee extensor muscle group were investigated in two groups of male human subjects performing two types of training exercises: supine leg press or/and seated knee extension. Results show that a training program in which both the concentric and the eccentric muscle action was performed led to substantially greater increases in maximal muscle strength than when only concentric exercises were performed.

Wetland management and rice farming strategies to decrease methylmercury bioaccumulation and loads from the Cosumnes River Preserve, California

USGS Publications Warehouse

Eagles-Smith, Collin A.; Ackerman, Joshua T.; Fleck, Jacob; Windham-Myers, Lisamarie; McQuillen, Harry; Heim, Wes

2014-01-01

We evaluated mercury (Hg) concentrations in caged fish (deployed for 30 days) and water from agricultural wetland (rice fields), managed wetland, slough, and river habitats in the Cosumnes River Preserve, California. We also implemented experimental hydrological regimes on managed wetlands and post-harvest rice straw management techniques on rice fields in order to evaluate potential Best Management Practices to decrease methylmercury bioaccumulation within wetlands and loads to the Sacramento-San Joaquin River Delta. Total Hg concentrations in caged fish were twice as high in rice fields as in managed wetland, slough, or riverine habitats, including seasonal managed wetlands subjected to identical hydrological regimes. Caged fish Hg concentrations also differed among managed wetland treatments and post-harvest rice straw treatments. Specifically, Hg concentrations in caged fish decreased from inlets to outlets in seasonal managed wetlands with either a single (fall-only) or dual (fall and spring) drawdown and flood-up events, whereas Hg concentrations increased slightly from inlets to outlets in permanent managed wetlands. In rice fields, experimental post-harvest straw management did not decrease Hg concentrations in caged fish. In fact, in fields in which rice straw was chopped and either disked into the soil or baled and removed from the fields, fish Hg concentrations increased from inlets to outlets and were higher than Hg concentrations in fish from rice fields subjected to the more standard post-harvest practice of simply chopping rice straw prior to fall flood-up. Finally, aqueous methylmercury (MeHg) concentrations and export were highly variable, and seasonal trends in particular were often opposite to those of caged fish. Aqueous MeHg concentrations and loads were substantially higher in winter than in summer, whereas caged fish Hg concentrations were relatively low in winter and substantially higher in summer. Together, our results highlight the importance of habitat, seasonal processes, and wetland management practices on Hg cycling and ecological risk in aquatic ecosystems.

Pharmacokinetic evidence for improved ophthalmic drug delivery by reduction of instilled volume.

PubMed

Patton, T F

1977-07-01

The bioavailability of topically applied pilocarpine nitrate was studied as a function of instilled volume. As the instilled volume decreased, the fraction of dose absorbed increased. The relationship between fraction absorbed and instilled volume was not direct, but appropriate adjustment of instilled volume and concentration should permit substantial dosage reductions without sacrifice of drug concentration in the eye. The implications of these findings from both a therapeutic and toxicity standpoint are discussed.

Examination of cortisol and state anxiety at an academic setting with and without oral presentation.

PubMed

Merz, Christian Josef; Wolf, Oliver Tobias

2015-01-01

Holding oral presentations in a university course is perceived as stressful and can increase stress hormone concentrations and state anxiety. In such a naturalistic setting, further attention should be paid to the relationship between psychological and hormonal measures of acute stress, as well as women's intake of hormonal contraceptives as a potential moderating variable. In the present study, 76 healthy students gave saliva samples before and after their oral presentations in a university course as well as on a second, control day in the same course without giving an oral presentation. Anticipatory state anxiety was rated on both days. Cortisol concentrations as well as state anxiety were substantially higher on the presentation relative to the control day. During the oral presentation, an increase in cortisol concentrations was observed, whereas a decrease occurred on the control day. Nearly the same picture emerged for both variables when looking at men, women taking hormonal contraceptives and free-cycling women separately. A positive correlation was found between the change in anticipatory state anxiety in the presentation compared to the control day and cortisol concentrations before and after the oral presentation. Concluding, oral presentations constitute a potent stressor and do not seem to be substantially different between men, free-cycling women and women taking hormonal contraceptives. Future studies may want to explore changes associated with specific menstrual cycle phases and with specific hormonal contraceptives.

SO 2 oxidation in an entraining cloud model with explicit microphysics

NASA Astrophysics Data System (ADS)

Bower, K. N.; Hill, T. A.; Coe, H.; Choularton, T. W.

A model of the chemical evolution of the droplets in a hill-cap cloud is presented. The chemistry of individual droplets forming on cloud condensation nuclei of differing size and chemical composition is considered, and the take-up of species from the gas phase by the droplets is treated explicity for the droplet population. Oxidation of S(IV) dissolved in cloud droplets is assumed to be dominated by hydrogen peroxide and ozone. Hydrogen peroxide is normally found to be the dominant oxidant for the oxidation of sulphur dioxide (except in the presence of substantial concentrations of ammonia gas, which increases droplet pH and the contribution made by the oxidant ozone). The entrainment of hydrogen peroxide from above the cloud top increases the amount of sulphate produced in conditions where the reaction is otherwise oxidant limited by the availability hydrogen peroxide. These conditions occur when there are high concentrations of sulphur dioxide accompanied by low cloudwater pH values. Within droplets formed on sodium chloride aerosol, reduced levels of acidity lead to an increase in sulphate production as a result of an enhanced reaction between SO 2 and the oxidant ozone. This results in an overall higher increase in cloudwater sulphate than would be expected assuming an even distribution of all reactants amongst the droplets. In addition, concentrations of the hydrogen sulphite ion predicted to occur in the cloudwater can be substantially in excess of those predicted from the bulk cloudwater pH. This is consistent with recent observations.

Summer diatom blooms in the North Pacific subtropical gyre: 2008-2009.

PubMed

Villareal, Tracy A; Brown, Colbi G; Brzezinski, Mark A; Krause, Jeffrey W; Wilson, Cara

2012-01-01

The summertime North Pacific subtropical gyre has widespread phytoplankton blooms between Hawaii and the subtropical front (∼30°N) that appear as chlorophyll (chl) increases in satellite ocean color data. Nitrogen-fixing diatom symbioses (diatom-diazotroph associations: DDAs) often increase 10(2)-10(3) fold in these blooms and contribute to elevated export flux. In 2008 and 2009, two cruises targeted satellite chlorophyll blooms to examine DDA species abundance, chlorophyll concentration, biogenic silica concentration, and hydrography. Generalized observations that DDA blooms occur when the mixed layer depth is < 70 m are supported, but there is no consistent relationship between mixed layer depth, bloom intensity, or composition; regional blooms between 22-34°N occur within a broader temperature range (21-26°C) than previously reported. In both years, the Hemiaulus-Richelia and Rhizosolenia-Richelia DDAs increased 10(2)-10(3) over background concentrations within satellite-defined bloom features. The two years share a common trend of Hemiaulus dominance of the DDAs and substantial increases in the >10 µm chl a fraction (∼40-90+% of total chl a). Integrated diatom abundance varied 10-fold over <10 km. Biogenic silica concentration tracked diatom abundance, was dominated by the >10 µm size fraction, and increased up to 5-fold in the blooms. The two years differed in the magnitude of the surface chl a increase (2009>2008), the abundance of pennate diatoms within the bloom (2009>2008), and the substantially greater mixed layer depth in 2009. Only the 2009 bloom had sufficient chl a in the >10 µm fraction to produce the observed ocean color chl increase. Blooms had high spatial variability; ocean color images likely average over numerous small events over time and space scales that exceed the individual event scale. Summertime DDA export flux noted at the Hawaii time-series Sta. ALOHA is probably a generalized feature of the eastern N. Pacific north to the subtropical front.

Climate Change, Offshore Wind Power, and the Coastal Zone Management Act

DTIC Science & Technology

2008-09-01

first century. Since the advent of the industrial revolution (ca. 1750), anthropogenic activities have resulted in a substantial increase in...concentrated sources of energy until the creation of the steam engine at the advent of the Industrial Revolution . Wind power was also widely employed in the

Increasing the percentage of renewable energy in the Southwestern United States

USDA-ARS?s Scientific Manuscript database

Combining the output of wind farms with that of Concentrating Solar Power (CSP) plants (including a heat storage system) resulted in a substantial percentage (40%) of the total utility electrical generation in the Southwestern United States being met by renewable energy. Using wind and solar resourc...

Television in the 80's: New Technologies, New Challenges.

ERIC Educational Resources Information Center

Alvarez, Sally

Electronic media have undergone substantial growth and change in the past two decades, and the structure of the programming industry has also changed, with the competition for programming becoming more intense. At the same time, government has moved toward deregulation in this area, with the result being increasing concentration,…

Wide-range particle characterization and elemental concentration in Beijing aerosol during the 2013 Spring Festival.

PubMed

Jing, Hui; Li, Yu-Feng; Zhao, Jiating; Li, Bai; Sun, Jialong; Chen, Rui; Gao, Yuxi; Chen, Chunying

2014-09-01

The number and mass concentration, size distribution, and the concentration of 16 elements were studied in aerosol samples during the Spring Festival celebrations in 2013 in Beijing, China. Both the number and mass concentration increased sharply in a wide range from 10 nm to 10 μm during the firecrackers and fireworks activities. The prominent increase of the number concentration was in 50 nm-500 nm with a peak of 1.7 × 10(5)/cm(3) at 150 nm, which is 8 times higher than that after 1.5 h. The highest mass concentration was in 320-560 nm, which is 4 times higher than the control. K, Mg, Sr, Ba and Pb increased sharply during the firework activities in PM10. Although the aerosol emission from firework activities is a short-term air quality degradation event, there may be a substantial hazard arising from the chemical composition of the emitted particles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Model evaluation of potential impacts of on-site wastewater systems on phosphorus in Turkey creek watershed.

PubMed

Geza, Mengistu; McCray, John E; Murray, Kyle E

2010-01-01

Nutrient loading to surface water systems has traditionally been associated with agricultural sources. Sources such as on-site wastewater systems (OWS) may be of concern especially in rural, nonagricultural watersheds. The impact of various point and nonpoint sources including OWS in Turkey Creek Watershed was evaluated using the Watershed Analysis Risk Management Framework, which was calibrated using 10 yr of observed stream flow and total P concentrations. Doubling the population in the watershed or OWS septic tank effluent P concentration increased mean stream total P concentration by a factor of 1.05. Converting all the OWS to a conventional sewer system with a removal efficiency of 93% at the wastewater treatment plant increased the mean total P concentration at the watershed outlet by a factor of 1.26. Reducing the soil adsorption capacity by 50% increased the mean stream total P concentration by a factor of 3.2. Doubling the initial P concentration increased the mean stream total P concentration by a factor of 1.96. Stream flow and sediment transport also substantially affected stream P concentration. The results suggest that OWS contribution to stream P in this watershed is minimal compared with other factors within the simulated time frame of 10 yr.

Solar concentration properties of flat fresnel lenses with large F-numbers

NASA Technical Reports Server (NTRS)

Cosby, R. M.

1978-01-01

The solar concentration performances of flat, line-focusing sun-tracking Fresnel lenses with selected f-numbers between 0.9 and 2.0 were analyzed. Lens transmittance was found to have a weak dependence on f-number, with a 2% increase occuring as the f-number is increased from 0.9 to 2.0. The geometric concentration ratio for perfectly tracking lenses peaked for an f-number near 1.35. Intensity profiles were more uniform over the image extent for large f-number lenses when compared to the f/0.9 lens results. Substantial decreases in geometri concentration ratios were observed for transverse tracking errors equal to or below 1 degree for all f-number lenses. With respect to tracking errors, the solar performance is optimum for f-numbers between 1.25 and 1.5.

Increasing minority carrier lifetime in as-grown multicrystalline silicon by low temperature internal gettering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Amin, M., E-mail: m.al-amin@warwick.ac.uk; Murphy, J. D., E-mail: john.d.murphy@warwick.ac.uk

2016-06-21

We report a systematic study into the effects of long low temperature (≤500 °C) annealing on the lifetime and interstitial iron distributions in as-grown multicrystalline silicon (mc-Si) from different ingot height positions. Samples are characterised in terms of dislocation density, and lifetime and interstitial iron concentration measurements are made at every stage using a temporary room temperature iodine-ethanol surface passivation scheme. Our measurement procedure allows these properties to be monitored during processing in a pseudo in situ way. Sufficient annealing at 300 °C and 400 °C increases lifetime in all cases studied, and annealing at 500 °C was only found to improve relatively poormore » wafers from the top and bottom of the block. We demonstrate that lifetime in poor as-grown wafers can be improved substantially by a low cost process in the absence of any bulk passivation which might result from a dielectric surface film. Substantial improvements are found in bottom wafers, for which annealing at 400 °C for 35 h increases lifetime from 5.5 μs to 38.7 μs. The lifetime of top wafers is improved from 12.1 μs to 23.8 μs under the same conditions. A correlation between interstitial iron concentration reduction and lifetime improvement is found in these cases. Surprisingly, although the interstitial iron concentration exceeds the expected solubility values, low temperature annealing seems to result in an initial increase in interstitial iron concentration, and any subsequent decay is a complex process driven not only by diffusion of interstitial iron.« less

Supplementing Monosodium Glutamate to Partial Enteral Nutrition Slows Gastric Emptying in Preterm Pigs123

PubMed Central

Bauchart-Thevret, Caroline; Stoll, Barbara; Benight, Nancy M.; Olutoye, Oluyinka; Lazar, David; Burrin, Douglas G.

2013-01-01

Emerging evidence suggests that free glutamate may play a functional role in modulating gastroduodenal motor function. We hypothesized that supplementing monosodium glutamate (MSG) to partial enteral nutrition stimulates gastric emptying in preterm pigs. Ten-day-old preterm, parenterally fed pigs received partial enteral nutrition (25%) as milk-based formula supplemented with MSG at 0, 1.7, 3.0, and 4.3 times the basal protein-bound glutamate intake (468 mg·kg−1·d−1) from d 4 to 8 of life (n = 5–8). Whole-body respiratory calorimetry and 13C-octanoic acid breath tests were performed on d 4, 6, and 8. Body weight gain, stomach and intestinal weights, and arterial plasma glutamate and glutamine concentrations were not different among the MSG groups. Arterial plasma glutamate concentrations were significantly higher at birth than after 8 d of partial enteral nutrition. Also at d 8, the significant portal-arterial concentration difference in plasma glutamate was substantial (∼500 μmol/L) among all treatment groups, suggesting that there was substantial net intestinal glutamate absorption in preterm pigs. MSG supplementation dose-dependently increased gastric emptying time and decreased breath 13CO2 enrichments, 13CO2 production, percentage of 13CO2 recovery/h, and cumulative percentage recovery of 13C-octanoic acid. Circulating glucagon-like peptide-2 (GLP-2) concentration was significantly increased by MSG but was not associated with an increase in intestinal mucosal growth. In contrast to our hypothesis, our results suggest that adding MSG to partial enteral nutrition slows the gastric emptying rate, which may be associated with an inhibitory effect of increased circulating GLP-2. PMID:23446960

Supplementing monosodium glutamate to partial enteral nutrition slows gastric emptying in preterm pigs(1-3).

PubMed

Bauchart-Thevret, Caroline; Stoll, Barbara; Benight, Nancy M; Olutoye, Oluyinka; Lazar, David; Burrin, Douglas G

2013-05-01

Emerging evidence suggests that free glutamate may play a functional role in modulating gastroduodenal motor function. We hypothesized that supplementing monosodium glutamate (MSG) to partial enteral nutrition stimulates gastric emptying in preterm pigs. Ten-day-old preterm, parenterally fed pigs received partial enteral nutrition (25%) as milk-based formula supplemented with MSG at 0, 1.7, 3.0, and 4.3 times the basal protein-bound glutamate intake (468 mg·kg(-1)·d(-1)) from d 4 to 8 of life (n = 5-8). Whole-body respiratory calorimetry and (13)C-octanoic acid breath tests were performed on d 4, 6, and 8. Body weight gain, stomach and intestinal weights, and arterial plasma glutamate and glutamine concentrations were not different among the MSG groups. Arterial plasma glutamate concentrations were significantly higher at birth than after 8 d of partial enteral nutrition. Also at d 8, the significant portal-arterial concentration difference in plasma glutamate was substantial (∼500 μmol/L) among all treatment groups, suggesting that there was substantial net intestinal glutamate absorption in preterm pigs. MSG supplementation dose-dependently increased gastric emptying time and decreased breath (13)CO2 enrichments, (13)CO2 production, percentage of (13)CO2 recovery/h, and cumulative percentage recovery of (13)C-octanoic acid. Circulating glucagon-like peptide-2 (GLP-2) concentration was significantly increased by MSG but was not associated with an increase in intestinal mucosal growth. In contrast to our hypothesis, our results suggest that adding MSG to partial enteral nutrition slows the gastric emptying rate, which may be associated with an inhibitory effect of increased circulating GLP-2.

Pharmaceutical manufacturing facility discharges can substantially increase the pharmaceutical load to U.S. wastewaters

USGS Publications Warehouse

Scott, Tia-Marie; Phillips, Patrick J.; Kolpin, Dana W.; Colella, Kaitlyn M.; Furlong, Edward T.; Foreman, William T.; Gray, James L.

2018-01-01

Discharges from pharmaceutical manufacturing facilities (PMFs) previously have been identified as important sources of pharmaceuticals to the environment. Yet few studies are available to establish the influence of PMFs on the pharmaceutical source contribution to wastewater treatment plants (WWTPs) and waterways at the national scale. Consequently, a national network of 13 WWTPs receiving PMF discharges, six WWTPs with no PMF input, and one WWTP that transitioned through a PMF closure were selected from across the United States to assess the influence of PMF inputs on pharmaceutical loading to WWTPs. Effluent samples were analyzed for 120 pharmaceuticals and pharmaceutical degradates. Of these, 33 pharmaceuticals had concentrations substantially higher in PMF-influenced effluent (maximum 555,000 ng/L) compared to effluent from control sites (maximum 175 ng/L). Concentrations in WWTP receiving PMF input are variable, as discharges from PMFs are episodic, indicating that production activities can vary substantially over relatively short (several months) periods and have the potential to rapidly transition to other pharmaceutical products. Results show that PMFs are an important, national-scale source of pharmaceuticals to the environment.

Surface-water-quality assessment of the lower Kansas River basin, Kansas and Nebraska; results of investigations, 1987-90

USGS Publications Warehouse

Helgesen, J.O.

1995-01-01

Surface-water-quality conditions and trends were assessed in the lower Kansas River Basin, which drains about 15,300 square miles of mainly agricultural land in southeast Nebraska and northeast Kansas. On the basis of established water-quality criteria, most streams in the basin were suitable for uses such as public-water supply, irrigation, and maintenance of aquatic life. However, most concerns identified from a previous analysis of available data through 1986 are substantiated by analysis of data for May 1987 through April 1990. Less-than-normal precipitation and runoff during 1987-90 affected surface-water quality and are important factors in the interpretation of results.Dissolved-solids concentrations in the main stem Kansas River during May 1987 through April 1990 commonly exceeded 500 milligrams per liter, which may be of concern for public-water supplies and for the irrigation of sensitive crops. Large concentrations of chloride in the Kansas River are derived from ground water discharging in the Smoky Hill River Basin west of the study unit. Trends of increasing concentrations of some dissolved major ions were statistically significant in the northwestern part of the study unit, which could reflect substantial increases in irrigated acreage.The largest concentrations of suspended sediment in streams during May 1987 through April 1990 were associated with high-density cropland in areas of little local relief and medium-density irrigated cropland in more dissected areas. The smallest concentrations were measured downstream from large reservoirs and in streams draining areas having little or no row-crop cultivation. Mean annual suspended-sediment transport rates in the main stem Kansas River increased substantially in the downstream direction. No conclusions could be reached concerning the relations of suspended-sediment transport, yields, or trends to natural and human factors.The largest sources of nitrogen and phosphorus in the study unit were fertilizer and livestock. Nitrate-nitrogen concentrations in stream-water samples did not exceed 10 milligams per liter; relatively large concentrations in the northwestern part of the study unit were associated with fertilizer application. Concentrations of total phosphorus generally were largest in the northwestern part of the study unit, which probably relates to the prevalence of cultivated land, fertilizer application, and livestock wastes.Deficiencies in dissolved-oxygen concentrations in streams occurred locally, as a result of discharges from wastewater-treatment plants, algal respiration, and inadequate reaeration associated with small streamflow. Large densities of a fecal-indicator bacterium, Escherichia coli, were associated with discharges from municipal wastewater-treatment plants and, especially in the northwestern part of the study unit, with transport of fecaThe largest concentrations of the herbicide atrazine generally were measured where the largest quantities of atrazine were applied to the land. Large atrazine concentrations, 10 to 20 micrograms per liter, were measured most frequently in unregulated principal streams during May and June. Downstream of reservoirs, the seasonal variability of atrazine concentrations was decreased compared to that of inflowing streams.

Polycarbonate Bottle Use and Urinary Bisphenol A Concentrations

PubMed Central

Carwile, Jenny L.; Luu, Henry T.; Bassett, Laura S.; Driscoll, Daniel A.; Yuan, Caterina; Chang, Jennifer Y.; Ye, Xiaoyun; Calafat, Antonia M.; Michels, Karin B.

2009-01-01

Background Bisphenol A (BPA) is a high-production-volume chemical commonly used in the manufacture of polycarbonate plastic. Low-level concentrations of BPA in animals and possibly in humans may cause endocrine disruption. Whether ingestion of food or beverages from polycarbonate containers increases BPA concentrations in humans has not been studied. Objectives We examined the association between use of polycarbonate beverage containers and urinary BPA concentrations in humans. Methods We conducted a nonrandomized intervention of 77 Harvard College students to compare urinary BPA concentrations collected after a washout phase of 1 week to those taken after an intervention week during which most cold beverages were consumed from polycarbonate drinking bottles. Paired t-tests were used to assess the difference in urinary BPA concentrations before and after polycarbonate bottle use. Results The geometric mean urinary BPA concentration at the end of the washout phase was 1.2 μg/g creatinine, increasing to 2.0 μg/g creatinine after 1 week of polycarbonate bottle use. Urinary BPA concentrations increased by 69% after use of polycarbonate bottles (p < 0.0001). The association was stronger among participants who reported ≥ 90% compliance (77% increase; p < 0.0001) than among those reporting < 90% compliance (55% increase; p = 0.03), but this difference was not statistically significant (p = 0.54). Conclusions One week of polycarbonate bottle use increased urinary BPA concentrations by two-thirds. Regular consumption of cold beverages from polycarbonate bottles is associated with a substantial increase in urinary BPA concentrations irrespective of exposure to BPA from other sources. PMID:19750099

Modeling of exposure to carbon monoxide in fires

NASA Technical Reports Server (NTRS)

Cagliostro, D. E.

1980-01-01

A mathematical model is developed to predict carboxyhemoglobin concentrations in regions of the body for short exposures to carbon monoxide levels expected during escape from aircraft fires. The model includes the respiratory and circulatory dynamics of absorption and distribution of carbon monoxide and carboxyhemoglobin. Predictions of carboxyhemoglobin concentrations are compared to experimental values obtained for human exposures to constant high carbon monoxide levels. Predictions are within 20% of experimental values. For short exposure times, transient concentration effects are predicted. The effect of stress is studied and found to increase carboxyhemoglobin levels substantially compared to a rest state.

Multi-species biofilms defined from drinking water microorganisms provide increased protection against chlorine disinfection.

PubMed

Schwering, Monika; Song, Joanna; Louie, Marie; Turner, Raymond J; Ceri, Howard

2013-09-01

A model biofilm, formed of multiple species from environmental drinking water, including opportunistic pathogens, was created to explore the tolerance of multi-species biofilms to chlorine levels typical of water-distribution systems. All species, when grown planktonically, were killed by concentrations of chlorine within the World Health Organization guidelines (0.2-5.0 mg l(-1)). Higher concentrations (1.6-40-fold) of chlorine were required to eradicate biofilm populations of these strains, ~70% of biofilms tested were not eradicated by 5.0 mg l(-1) chlorine. Pathogenic bacteria within the model multi-species biofilms had an even more substantial increase in chlorine tolerance; on average ~700-1100 mg l(-1) chlorine was required to eliminate pathogens from the biofilm, 50-300-fold higher than for biofilms comprising single species. Confocal laser scanning microscopy of biofilms showed distinct 3D structures and multiple cell morphologies and arrangements. Overall, this study showed a substantial increase in the chlorine tolerance of individual species with co-colonization in a multi-species biofilm that was far beyond that expected as a result of biofilm growth on its own.

Low-Concentration Kinetics of Atmospheric CH4 Oxidation in Soil and Mechanism of NH4+ Inhibition

PubMed Central

Gulledge, Jay; Schimel, Joshua P.

1998-01-01

NH4+ inhibition kinetics for CH4 oxidation were examined at near-atmospheric CH4 concentrations in three upland forest soils. Whether NH4+-independent salt effects could be neutralized by adding nonammoniacal salts to control samples in lieu of deionized water was also investigated. Because the levels of exchangeable endogenous NH4+ were very low in the three soils, desorption of endogenous NH4+ was not a significant factor in this study. The Km(app) values for water-treated controls were 9.8, 22, and 57 nM for temperate pine, temperate hardwood, and birch taiga soils, respectively. At CH4 concentrations of ≤15 μl liter−1, oxidation followed first-order kinetics in the fine-textured taiga soil, whereas the coarse-textured temperate soils exhibited Michaelis-Menten kinetics. Compared to water controls, the Km(app) values in the temperate soils increased in the presence of NH4+ salts, whereas the Vmax(app) values decreased substantially, indicating that there was a mixture of competitive and noncompetitive inhibition mechanisms for whole NH4+ salts. Compared to the corresponding K+ salt controls, the Km(app) values for NH4+ salts increased substantially, whereas the Vmax(app) values remained virtually unchanged, indicating that NH4+ acted by competitive inhibition. Nonammoniacal salts caused inhibition to increase with increasing CH4 concentrations in all three soils. In the birch taiga soil, this trend occurred with both NH4+ and K+ salts, and the slope of the increase was not affected by the addition of NH4+. Hence, the increase in inhibition resulted from an NH4+-independent mechanism. These results show that NH4+ inhibition of atmospheric CH4 oxidation resulted from enzymatic substrate competition and that additional inhibition that was not competitive resulted from a general salt effect that was independent of NH4+. PMID:9797279

Low-concentration kinetics of atmospheric CH{sub 4} oxidation in soil and mechanism of NH{sub 4}{sup +} inhibition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gulledge, J.; Schimel, J.P.

1998-11-01

NH{sub 4}{sup +} inhibition kinetics for CH{sub 4} oxidation were examined at near-atmospheric CH{sub 4} concentrations in three upland forest soils. Whether NH{sub 4}{sup +}-independent salt effects could be neutralized by adding nonammoniacal salts to control samples in lieu of deionized water was also investigated. Because the levels of exchangeable endogenous NH{sub 4}{sup +} were very low in the three soils, desorption of endogenous NH{sub 4}{sup +} was not a significant factor in this study. The K{sub m(app)} values for water-treated controls were 9.8, 22, and 57 nM for temperate pine, temperate hardwood, and birch taiga soils, respectively. At CH{submore » 4} concentrations of {le}15 {micro}l liter{sup {minus}1}, oxidation followed first-order kinetics in the fine-textured taiga soil, whereas the coarse-textured temperate soils exhibited Michaelis-Menten kinetics. Compared to water controls, the K{sub m(app)} values in the temperate soils increased in the presence of NH{sub 4}{sup +} salts, whereas the V{sub max(app)} values decreased substantially, indicating that there was a mixture of competitive and noncompetitive inhibition mechanisms for whole NH{sub 4}{sup +} salts. Compared to the corresponding K{sup +} salt controls, the K{sub m(app)} values for NH{sub 4}{sup +} salts increased substantially, whereas the V{sub max(app)} values remained virtually unchanged, indicating that NH{sub 4}{sup +} acted by competitive inhibition. Nonammoniacal salts caused inhibition to increase with increasing CH{sub 4} concentrations in all three soils. In the birch taiga soil, this trend occurred with both NH{sub 4}{sup +} and K{sup +} salts, and the slope of the increase was not affected by the addition of NH{sub 4}{sup +}. Hence, the increase in inhibition resulted from an NH{sub 4}{sup +}-independent mechanism.« less

The effect of ethylene glycol on pore arrangement of anodic aluminium oxide prepared by hard anodization

NASA Astrophysics Data System (ADS)

Guo, Yang; Zhang, Li; Han, Mangui; Wang, Xin; Xie, Jianliang; Deng, Longjiang

2018-03-01

The influence of the addition of ethylene glycol (EG) on the pore self-ordering process in anodic aluminium oxide (AAO) membranes prepared by hard anodization (HA) was investigated. It was illustrated that EG has a substantial effect on the pore arrangement of AAO, and it was found that a smaller pore size can be obtained with an EG concentration reaching 20 wt% in aqueous electrolyte. The number of estimated defects of AAO increases significantly with an increase in EG concentration to 50 wt%. Excellent ordering of pores was realized when the samples were anodized in the 30 wt%-EG-containing aqueous electrolyte.

Hydrology, aquatic macrophytes, and water quality of Black Earth Creek and its tributaries, Dane County, Wisconsin, 1985-86

USGS Publications Warehouse

Field, S.J.; Graczyk, D.J.

1990-01-01

An increase in oxygen demand, caused by agricultural runoff, has resulted in reduced dissolved-oxygen content of the water in both Black Earth and Garfoot Creeks. The most substantial reduction occurred at Black Earth Creek at Cross Plains on July 25, 1985, as a result of the largest storm runoff event during the study. A rainfall of 5.54 inches caused streamflow discharges to increase from 9 to 122 ft3/s and dissolved-oxygen concentrations to decline to 3.0 mg/L; the dissolved-oxygen concentration was less than 6.0 mg/L for 30 hours.

Interactive effects of soil acidity and fluoride on soil solution aluminium chemistry and barley (Hordeum vulgare L.) root growth.

PubMed

Manoharan, V; Loganathan, P; Tillman, R W; Parfitt, R L

2007-02-01

A greenhouse study was conducted to determine if concentrations of fluoride (F), which would be added to acid soils via P fertilisers, were detrimental to barley root growth. Increasing rates of F additions to soil significantly increased the soil solution concentrations of aluminium (Al) and F irrespective of the initial adjusted soil pH, which ranged from 4.25 to 5.48. High rates of F addition severely restricted root growth; the effect was more pronounced in the strongly acidic soil. Speciation calculations demonstrated that increasing rates of F additions substantially increased the concentrations of Al-F complexes in the soil. Stepwise regression analysis showed that it was the combination of the activities of AlF2(1+) and AlF(2+) complexes that primarily controlled barley root growth. The results suggested that continuous input of F to soils, and increased soil acidification, may become an F risk issue in the future.

Nitrate in aquifers beneath agricultural systems

USGS Publications Warehouse

Burkart, M.R.; Stoner, J.D.; ,

2007-01-01

Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and also shallow carbonate aquifers that provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The system of corn, soybean, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems because this system imports the largest amount of N-fertilizer per unit production area. Mean nitrate under dairy, poultry, horticulture, and cattle and grains systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of this practice on groundwater nitrate. ?? USDA 2007.

Solvent and viscosity effects on the rate-limiting product release step of glucoamylase during maltose hydrolysis.

PubMed

Sierks, M R; Sico, C; Zaw, M

1997-01-01

Release of product from the active site is the rate-limiting step in a number of enzymatic reactions, including maltose hydrolysis by glucoamylase (GA). With GA, an enzymatic conformational change has been associated with the product release step. Solvent characteristics such as viscosity can strongly influence protein conformational changes. Here we show that the rate-limiting step of GA has a rather complex dependence on solvent characteristics. Seven different cosolvents were added to the GA/maltose reaction solution. Five of the cosolvents, all having an ethylene glycol base, resulted in an increase in activity at low concentration of cosolvent and variable decreases in activity at higher concentrations. The increase in enzyme activity was dependent on polymer length of the cosolvent; the longer the polymer, the lower the concentration needed. The maximum increase in catalytic activity at 45 degrees C (40-45%) was obtained with the three longest polymers (degree of polymerization from 200 to 8000). A further increase in activity to 60-65% was obtained at 60 degrees C. The linear relationship between ln(kcat) and (viscosity)2 obtained with all the cosolvents provides further evidence that product release is the rate-limiting step in the GA catalytic mechanism. A substantial increase in the turnover rate of GA by addition of relatively small amounts of a cosolvent has potential applications for the food industry where high-fructose corn syrup (HFCS) is one of the primary products produced with GA. Since maltodextrin hydrolysis by GA is by far the slowest step in the production of HFCS, increasing the catalytic rate of GA can substantially reduce the process time.

Trends in pesticide concentrations and use for major rivers of the United States

USGS Publications Warehouse

Ryberg, Karen R.; Gilliom, Robert J.

2015-01-01

Pesticides strongly dominated by agricultural use (cyanazine, alachlor, atrazine and its degradate deethylatrazine, metolachlor, and carbofuran) had widespread agreement between concentration trends and use trends. Pesticides with substantial use in both agricultural and nonagricultural applications (simazine, chlorpyrifos, malathion, diazinon, and carbaryl) had concentration trends that were mostly explained by a combination of agricultural-use trends, regulatory changes, and urban use changes inferred from concentration trends in urban streams. When there were differences, concentration trends usually were greater than use trends (increased more or decreased less). These differences may occur because of such factors as unaccounted pesticide uses, delayed transport to the river through groundwater, greater uncertainty in the use data, or unquantified land use and management practice changes.

Twenty-year inter-annual trends and seasonal variations in precipitation and stream water chemistry at the Bear Brook Watershed in Maine, USA.

PubMed

Navrátil, Tomas; Norton, Stephen A; Fernandez, Ivan J; Nelson, Sarah J

2010-12-01

Mean annual concentration of SO4(-2) in wet-only deposition has decreased between 1988 and 2006 at the paired watershed study at Bear Brook Watershed in Maine, USA (BBWM) due to substantially decreased emissions of SO(2). Emissions of NO(x) have not changed substantially, but deposition has declined slightly at BBWM. Base cations, NH4+, and Cl(-) concentrations were largely unchanged, with small irregular changes of <1 μeq L(-1) per year from 1988 to 2006. Precipitation chemistry, hydrology, vegetation, and temperature drive seasonal stream chemistry. Low flow periods were typical in June-October, with relatively greater contributions of deeper flow solutions with higher pH; higher concentrations of acid-neutralizing capacity, Si, and non-marine Na; and low concentrations of inorganic Al. High flow periods during November-May were typically dominated by solutions following shallow flow paths, which were characterized by lower pH and higher Al and DOC concentrations. Biological activity strongly controlled NO3- and K(+). They were depressed during the growing season and elevated in the fall. Since 1987, East Bear Brook (EB), the reference stream, has been slowly responding to reduced but still elevated acid deposition. Calcium and Mg have declined fairly steadily and faster than SO4(-2), with consequent acidification (lower pH and higher inorganic Al). Eighteen years of experimental treatment with (NH(4))(2)SO(4) enhanced acidification of West Bear Brook's (WB) watershed. Despite the manipulation, NH4+ concentration remained below detection limits at WB, while leaching of NO3- increased. The seasonal pattern for NO3- concentrations in WB, however, remained similar to EB. Mean monthly concentrations of SO4(-2) have increased in WB since 1989, initially only during periods of high flow, but gradually also during base flow. Increases in mean monthly concentrations of Ca(2+), Mg(2+), and K(+) due to the manipulation occurred from 1989 until about 1995, during the depletion of base cations in shallow flow paths in WB. Progressive depletion of Ca and Mg at greater soil depth occurred, causing stream concentrations to decline to pre-manipulation values. Mean monthly Si concentrations did not change in EB or WB, suggesting that the manipulation had no effect on mineral weathering rates. DOC concentrations in both streams did not exhibit inter- or intra-annual trends.

Urban tree effects on fine particulate matter and human health

Treesearch

David J. Nowak

2014-01-01

Overall, city trees reduce particulate matter and provide substantial health benefits; but under certain conditions, they can locally increase particulate matter concentrations. Urban foresters need to understand how trees affect particulate matter so they can select proper species and create appropriate designs to improve air quality. This article details trees'...

Influence of Boiling Duration of GCSB-5 on Index Compound Content and Antioxidative and Anti-inflammatory Activity.

PubMed

Lee, In-Hee; Chung, Hwa-Jin; Shin, Joon-Shik; Ha, In-Hyuk; Kim, Me-Riong; Koh, Wonil; Lee, Jinho

2017-01-01

GCSB-5, an herbal drug composition with an anti-inflammatory effect, is prepared by boiling, which is the most common herbal extraction method in traditional Korean medicine. Several parameters are involved in the process, i.e., extractant type, herb-to-extractant ratio, extraction temperature and pressure, and total boiling time. The aim of this study was to examine the influence of boiling time on index compound amount and the antioxidative and anti-inflammatory activities of GCSB-5. Different samples of GCSB-5 were obtained by decocting for 30, 60, 90, 120, 150, and 240 min. Each sample was tested for hydrogen ion concentration (pH), total soluble solid content (TSSC), marker compound profiles, and antioxidative and anti-inflammatory activity. pH was found to decrease while TSSC increased with extended decoction. Marker compound contents for GCSB-5 (acanthoside D for Acanthopanax sessiliflorus Seem, 20-hydroxyecdysone for Achyranthes japonica Nakai, and pinoresinol diglucoside for Eucommia ulmoides Oliver) remained relatively constant regardless of the length of boiling. Total D-glucose amount increased with longer boiling. The antioxidative and anti-inflammatory potentials of GCSB-5 were not substantially affected by decoction duration. Biological characteristics and marker compound content of GCSB-5 were not altered significantly in prolonged boiling. Longer boiling duration of GCSB-5 did not increase yield in a time-dependent manner, but yields of 210 and 240 min samples were significantly higherHydrogen ion concentration of GCSB-5 samples decreased while total soluble solid content and D-glucose concentration levels increased with boiling durationAlthough concentrations of some index compounds increased with extended boiling duration of GCSB-5, increase was small and not in a direct proportional relationshipAntioxidative and anti-inflammatory properties of GCSB-5 were not substantially affected by decoction duration. Abbreviations used: CAM: Complementary and alternative medicine; KIOM: Korea Institute of Oriental Medicine; KMD: Korean medicine doctor; TSSC: Total soluble solid content; pH: Hydrogen ion concentration; HPLC: High-performance liquid chromatography; NO: Nitric oxide; NO 2 : Nitric dioxide; LPS: Lipopolysaccharide; DMSO: Dimethyl sulfoxide.

Localized stress fluctuations drive shear thickening in dense suspensions

NASA Astrophysics Data System (ADS)

Rathee, Vikram; Blair, Daniel L.; Urbach, Jeffrey S.

2017-08-01

Dense particulate suspensions exhibit a dramatic increase in average viscosity above a critical, material-dependent shear stress. This thickening changes from continuous to discontinuous as the concentration is increased. Using direct measurements of spatially resolved surface stresses in the continuous thickening regime, we report the existence of clearly defined dynamic localized regions of substantially increased stress that appear intermittently at stresses above the critical stress. With increasing applied stress, these regions occupy an increasing fraction of the system, and the increase accounts quantitatively for the observed shear thickening. The regions represent high-viscosity fluid phases, with a size determined by the distance between the shearing surfaces and a viscosity that is nearly independent of shear rate but that increases rapidly with concentration. Thus, we find that continuous shear thickening arises from increasingly frequent localized discontinuous transitions between distinct fluid phases with widely differing viscosities.

Are phloem-derived amino acids the origin of the elevated malate concentration in the xylem sap following mineral N starvation in soybean?

PubMed

Vitor, Simone C; do Amarante, Luciano; Sodek, Ladaslav

2018-05-16

A substantial increase in malate in the xylem sap of soybean subjected to mineral N starvation originates mainly from aspartate, a prominent amino acid of the phloem. A substantial increase in xylem malate was found when non-nodulated soybean plants were transferred to a N-free medium. Nodulated plants growing in the absence of mineral N and, therefore, dependent on symbiotic N 2 fixation also contained elevated concentrations of malate in the xylem sap. When either nitrate or ammonium was supplied, malate concentrations in the xylem sap were low, both for nodulated and non-nodulated plants. Evidence was obtained that the elevated malate concentration of the xylem was derived from amino acids supplied by the phloem. Aspartate was a prominent component of the phloem sap amino acids and, therefore, a potential source of malate. Supplying the roots of intact plants with 13 C-aspartate revealed that malate of the xylem sap was readily labelled under N starvation. A hypothetical scheme is proposed whereby aspartate supplied by the phloem is metabolised in the roots and the products of this metabolism cycled back to the shoot. Under N starvation, aspartate metabolism is diverted from asparagine synthesis to supply N for the synthesis of other amino acids via transaminase activity. The by-product of aspartate transaminase activity, oxaloacetate, is transformed to malate and its export accounts for much of the elevated concentration of malate found in the xylem sap. This mechanism represents a new additional role for malate during mineral N starvation of soybean, beyond that of charge balance.

Monsoon Related Fluctuations in Terrigenous Sedimentation and Biological Productivity in the Bay of Bengal During the Past 24,500 Years

NASA Astrophysics Data System (ADS)

K V, S.; Kurian, J.; Meloth, T.; Rasik, R.

2011-12-01

Reconstruction of the Indian monsoon precipitation on a centennial to millennial scale has important relevance on the future climate and hydrologic change over the entire South Asia. Here we present paleo-monsoon records from a AMS 14C dated sediment core from the Bay of Bengal (ABP-24/01; location - 11°15.52' N & 90°21.84' E, water depth - 3206 m) that span the past 24.5 ka BP (calendar age). The array of inorganic and organic geochemical proxy records examined here assist the reconstruction of monsoon associated precipitation/ runoff, oceanic productivity and water column processes during the last glacial maximum (LGM ~21±2 ka BP) to the late Holocene. During the early stages of LGM, terrigenous elemental concentrations (Al, Fe) remained low, with substantial increase towards late LGM stage. Significantly, the substantial LGM increase in the eolian proxy concentrations (Mg, Rb) suggest that with the diminishing strength of the rain bearing SW monsoon during LGM the dry NE monsoon strengthened, leading to increased dust input to the Bay of Bengal. Although the LGM biological productivity (Corg, CaCO3, Ba) at the site remained low due to the relative decrease in runoff-derived nutrients, the ocean bottom seems to have less ventilated (Mn, U, V). The deglacial period is associated with slightly increasing monsoonal runoff increasing trend in terrigenous input, without any increase in biological productivity. Interestingly, the enhanced terrigenous input to the core site occurred during 12.5 - 10 ka BP. The Holocene was characterised by a dramatic increase in biological productivity between 8.5 and 7 ka BP as well as relatively enhanced river influx. While the various proxy records suggest a substantial decrease in monsoonal terrigenous influx after 7 ka BP, the productivity records remained at elevated values with better ventilated bottom waters.

Effects of sodium dodecyl sulfate on the conformation and hemolytic activity of St I and St II, two isotoxins purified from Stichodactyla helianthus.

PubMed

Lanio, M E; Alvarez, C; Pazos, F; Martinez, D; Martínez, Y; Casallanovo, F; Abuin, E; Schreier, S; Lissi, E

2003-01-01

The effect of sodium dodecyl sulfate (SDS) upon the conformation and hemolytic activity of St I and St II strongly depends on its concentration. At relatively low surfactant concentrations (ca. 0.5-5mM range) the surfactant leads to the formation of aggregates, as suggested by the turbidity observed even at relatively low (micromolar range) protein concentrations. In this surfactant range, the proteins show an increase in intrinsic fluorescence intensity and reduced quenching by acrylamide, with an almost total loss of its hemolytic activity. At higher surfactant concentrations the protein adducts disaggregates. This produces a decrease in fluorescence intensity, increase in quenching efficiency by acrylamide, loss of the native tertiary conformation (as reported by the near UV-CD spectra), and increase in alpha-helix content (as evidenced by the far UV-CD spectra). However, and in spite of these substantial changes, the toxins partially recover their hemolytic activity. The reasons for this recovering of the activity at high surfactant concentrations is discussed.

The effects of Hurricane Irene and Tropical Storm Lee on the bed sediment geochemistry of U.S. Atlantic coastal rivers

USGS Publications Warehouse

Horowitz, Arthur J.

2013-01-01

Hurricane Irene and Tropical Storm Lee, both of which made landfall in the U.S. between late August and early September 2011, generated record or near record water discharges in 41 coastal rivers between the North Carolina/South Carolina border and the U.S./Canadian border. Despite the discharge of substantial amounts of suspended sediment from many of these rivers, as well as the probable influx of substantial amounts of eroded material from the surrounding basins, the geochemical effects on the <63-µm fractions of the bed sediments appear relatively limited [<20% of the constituents determined (256 out of 1394)]. Based on surface area measurements, this lack of change occurred despite substantial alterations in both the grain size distribution and the composition of the bed sediments. The sediment-associated constituents which display both concentration increases and decreases include: total sulfur (TS), Hg, Ag, total organic carbon (TOC), total nitrogen (TN), Zn, Se, Co, Cu, Pb, As, Cr, and total carbon (TC). As a group, these constituents tend to be associated either with urbanization/elevated population densities and/or wastewater/solid sludge. The limited number of significant sediment-associated chemical changes that were detected probably resulted from two potential processes: (1) the flushing of in-stream land-use affected sediments that were replaced by baseline material more representative of local geology and/or soils (declining concentrations), and/or (2) the inclusion of more heavily affected material as a result of urban nonpoint-source runoff and/or releases from flooded treatment facilities (increasing concentrations). Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Rapid determination of surfactant critical micelle concentration in aqueous solutions using fiber-optic refractive index sensing.

PubMed

Tan, Chun Hua; Huang, Zhen Jian; Huang, Xu Guang

2010-06-01

We describe a simple and rapid method for determining the critical micelle concentration (CMC) of surfactants from fiber-optic measurements of refractive index. The refractive index of an aqueous surfactant solution was monitored as the surfactant concentration was increased using an automated dispensing system. On reaching the surfactant's CMC value, an abrupt change was observed in the rate of increase of the refractive index with increasing concentration. The measurement system provides rapid semiautomatic data collection and analysis, increasing the precision, sensitivity, and range of applicability of the technique while substantially decreasing the amount of manual intervention required. Measurements of CMC for sodium dodecyl sulfate (8.10mM), cetyltrimethylammonium chloride (1.58mM), and Triton X-100 (0.21mM) were in excellent agreement with values previously reported in the literature. The method is applicable to cationic, anionic, and nonionic surfactants, and it offers a facile, in situ, and sensitive means of detecting micelle formation over a broad range of CMC values larger than 10(-1)mM. Copyright 2010 Elsevier Inc. All rights reserved.

Clinical biochemistry of pregnant and nursing mares.

PubMed

Harvey, John W; Pate, Melanie G; Kivipelto, Jan; Asquith, Richard L

2005-09-01

Pregnancy and lactation result in increased metabolic demands. Although homeostatic mechanisms function to keep substances in blood at relatively constant levels, some changes in the concentrations of routine clinical chemistry analytes are likely to occur. The purpose of this study was to determine what physiological changes occur in serum clinical biochemistry analytes in pregnant and nursing mares, and to determine whether the changes were substantial enough to warrant separate reference intervals for pregnant or lactating horses. Forty-two Quarter Horse, Thoroughbred, Saddlebred, Standardbred and Morgan mares were entered into the study while pregnant. They were bled once each month through birth. Studies were continued on 20 mares until their foals were weaned. Test results were tabulated by time before or after birth. Serum biochemistry values were determined by standard methods using automated analyzers. Test results were analyzed using the Kruskal-Wallis 1-way ANOVA on ranks. If a significant difference was found (P<.05), Dunn's multiple comparison procedure was performed on all pairs. Results from pregnant and nursing mares also were compared with a reference group of 19 open, nonlactating mares. Serum triglyceride, potassium, creatinine, and total bilirubin concentrations were lower during lactation than during pregnancy. Serum calcium concentration also was slightly decreased at 2 time points during lactation. Triglyceride concentration was highest during midgestation, while bilirubin and creatinine values increased, and potassium and calcium remained constant during pregnancy. Serum urea concentration also remained constant during pregnancy but increased during lactation. Serum phosphate concentration was lowest during midgestation and highest during lactation. Total CO2 values were highest, and anion gaps were lowest, during midgestation. No significant differences were found in serum albumin, globulin, albumin:globulin ratio, total protein, or glucose values. When compared with the reference group of open mares, serum triglyceride, potassium, bilirubin, and total CO2 concentrations were lower, and anion gap was higher in horses that were nursing. Although most biochemical values remained relatively constant, significant differences were observed during pregnancy and lactation. Changes in the concentrations of triglycerides, potassium, bilirubin, total CO2, and anion gap during lactation were substantial enough to warrant separate reference intervals for lactating horses.

Dying piece by piece: carbohydrate dynamics in aspen (Populus tremuloides) seedlings under severe carbon stress.

PubMed

Wiley, Erin; Hoch, Günter; Landhäusser, Simon M

2017-11-02

Carbon starvation as a mechanism of tree mortality is poorly understood. We exposed seedlings of aspen (Populus tremuloides) to complete darkness at 20 or 28 °C to identify minimum non-structural carbohydrate (NSC) concentrations at which trees die and to see if these levels vary between organs or with environmental conditions. We also first grew seedlings under different shade levels to determine if size affects survival time under darkness due to changes in initial NSC concentration and pool size and/or respiration rates. Darkness treatments caused a gradual dieback of tissues. Even after half the stem had died, substantial starch reserves were still present in the roots (1.3-3% dry weight), indicating limitations to carbohydrate remobilization and/or transport during starvation in the absence of water stress. Survival time decreased with increased temperature and with increasing initial shade level, which was associated with smaller biomass, higher respiration rates, and initially smaller NSC pool size. Dead tissues generally contained no starch, but sugar concentrations were substantially above zero and differed between organs (~2% in stems up to ~7.5% in leaves) and, at times, between temperature treatments and initial, pre-darkness shade treatments. Minimum root NSC concentrations were difficult to determine because dead roots quickly began to decompose, but we identify 5-6% sugar as a potential threshold for living roots. This variability may complicate efforts to identify critical NSC thresholds below which trees starve. © Society for Experimental Biology 2017.

A steady-state mechanism can account for the properties of inositol 2,4,5-trisphosphate-stimulated Ca2+ release from permeabilized L1210 cells.

PubMed Central

Loomis-Husselbee, J W; Dawson, A P

1993-01-01

We have investigated the effects of sub-maximal Ins(2,4,5)P3 concentrations on the Ca2+ permeability of the residual undischarged Ca2+ stores in electroporated or digitonin-permeabilized L1210 cells by measuring Ca(2+)-efflux rate after addition of the ATPase inhibitor thapsigargin. Low concentrations of Ins(2,4,5)P3, causing rapid discharge of a small proportion of the releasable Ca2+, result in a substantial stimulation of Ca2+ efflux after thapsigargin addition. This indicates firstly that in the absence of thapsigargin there must have been a substantial, counterbalancing, increase in rate of Ca2+ pumping, and secondly that the increased Ca2+ permeability is more consistent with a steady state than with a quantal model of Ca2+ release. Similar increases in passive Ca2+ permeability are produced by addition of concentrations of ionomycin which produce equivalent changes in Ca2+ loading to those produced by Ins(2,4,5)P3, although the time course and initial rate of Ca2+ release are very much slower. In the presence of a Ca(2+)-buffering system, the time course of Ca2+ release by Ins(2,4,5)P3 becomes superimposable on that of ionomycin, indicating that the initial rapid phase of Ins(2,4,5)P3-stimulated Ca2+ is at least partially due to positive feedback from extravesicular Ca2+. PMID:8382056

Stirling Engine With Radial Flow Heat Exchangers

NASA Technical Reports Server (NTRS)

Vitale, N.; Yarr, George

1993-01-01

Conflict between thermodynamical and structural requirements resolved. In Stirling engine of new cylindrical configuration, regenerator and acceptor and rejector heat exchangers channel flow of working gas in radial direction. Isotherms in regenerator ideally concentric cylinders, and gradient of temperature across regenerator radial rather than axial. Acceptor and rejector heat exchangers located radially inward and outward of regenerator, respectively. Enables substantial increase in power of engine without corresponding increase in diameter of pressure vessel.

Implications of shale gas development for climate change.

PubMed

Newell, Richard G; Raimi, Daniel

2014-01-01

Advances in technologies for extracting oil and gas from shale formations have dramatically increased U.S. production of natural gas. As production expands domestically and abroad, natural gas prices will be lower than without shale gas. Lower prices have two main effects: increasing overall energy consumption, and encouraging substitution away from sources such as coal, nuclear, renewables, and electricity. We examine the evidence and analyze modeling projections to understand how these two dynamics affect greenhouse gas emissions. Most evidence indicates that natural gas as a substitute for coal in electricity production, gasoline in transport, and electricity in buildings decreases greenhouse gases, although as an electricity substitute this depends on the electricity mix displaced. Modeling suggests that absent substantial policy changes, increased natural gas production slightly increases overall energy use, more substantially encourages fuel-switching, and that the combined effect slightly alters economy wide GHG emissions; whether the net effect is a slight decrease or increase depends on modeling assumptions including upstream methane emissions. Our main conclusions are that natural gas can help reduce GHG emissions, but in the absence of targeted climate policy measures, it will not substantially change the course of global GHG concentrations. Abundant natural gas can, however, help reduce the costs of achieving GHG reduction goals.

Heavy metal speciation and uptake in crayfish and tadpoles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bundy, K.J.; Berzins, D.; Millet, L.

1996-12-31

Developing valid pollution recording methods is central to assessing environmental damage and remediation. This often is difficult, however, because of speciation and multiphase distribution of contaminants. Polarography, an electroanalytical technique capable of detection and quantification of trace levels of elements and ionic complexes, is a promising method for analyzing environmental samples. Here, polarography has been used to determine lead concentration in water, sediment, bullfrogs, tadpoles, and adsorbed onto kaolin. It has also been used to measure hexavalent chromium concentration in crayfish. This research involves field studies and two laboratory experiments. Studies of a Louisiana swamp have shown lead`s affinity formore » sediment and water particulate phases, rather than being ionically dissolved in the aqueous phase. In swamp bullfrogs, lead was found in greater concentrations in bone compared to muscle. In the first laboratory experiment, lead uptake originating from water and sediment increased in tadpoles as exposure time and concentration increased. Also, this animal`s development was hindered at higher concentrations. The second laboratory experiment exposed crayfish to aqueous hexavalent chromium. Total chromium uptake increased with exposure time and concentration. The chromium tissue abundance was hepatopancreas > gills > muscle. A substantial portion of tissue hexavalent chromium converted to the less toxic trivalent form.« less

Prediction of indoor radon/thoron concentration in a model room from exhalation rates of building materials for different ventilation rates

NASA Astrophysics Data System (ADS)

Kumar, Manish; Sharma, Navjeet; Sarin, Amit

2018-05-01

Studies have confirmed that elevated levels of radon/thoron in the human-environments can substantially increase the risk of lung cancer in general population. The building materials are the second largest contributors to indoor radon/thoron after soil and bedrock beneath dwellings. In present investigation, the exhalation rates of radon/thoron from different building materials samples have been analysed using active technique. Radon/thoron concentrations in a model room have been predicted based on the exhalation rates from walls, floor and roof. The indoor concentrations show significant variations depending upon the ventilation rate and type of building materials used.

The development of substitute inks and controls for reducing workplace concentrations of organic solvent vapors in a vinyl shower curtain printing plant.

PubMed

Piltingsrud, Harley V; Zimmer, Anthony T; Rourke, Aaron B

2003-08-01

During the summer of 1994, football players at a practice field reported noxious odors in the area. Ohio Environmental Protection Agency (OEPA) investigations of industries surrounding the field included a printing facility producing vinyl shower curtains with screen-printed designs. Though not the source of the odor, they were discharging volatile organic compounds directly to the environs in violation of OEPA regulations. To achieve compliance they installed a catalytic oxidizer for treating discharged air. Due to high equipment costs, the capacity of the installed catalytic oxidizer resulted in a substantial reduction in discharged air flow rates and increased solvent vapor concentrations within the workplace. Vapor levels caused worker discomfort, prompting a request for assistance from the Ohio Bureau of Workers Compensation. The vapor concentrations were found to exceed NIOSH, OSHA, and ACGIH acceptable exposure levels. The workers were then required to wear organic vapor removing respirators full-time while printing as a temporary protective measure. The company requested NIOSH assistance in finding methods to reduce solvent vapor concentrations. NIOSH studies included the identification of the sources and relative magnitude of solvent emissions from the printing process, the design of controls for the emissions, and the development of substitute inks using non-photochemically reactive solvents. The new ink system and controls allowed OEPA removal of the requirement for the treatment of discharged air and substantial increases in dilution ventilation. Increased ventilation would permit reduction in worker exposures to less than 1/3 mixture TLV levels and removal of requirements for respirator usage. This solution was the result of a comprehensive review of all facets of the problem, including OEPA regulations. It also required cooperative work between the company and federal, state, and local governmental agencies.

Characterizing distributions of surface ozone and its impact on grain production in China, Japan and South Korea: 1990 and 2020

NASA Astrophysics Data System (ADS)

Wang, Xiaoping; Mauzerall, Denise L.

Using an integrated assessment approach, we evaluate the impact that surface O 3 in East Asia had on agricultural production in 1990 and is projected to have in 2020. We also examine the effect that emission controls and the enforcement of environmental standards could have in increasing grain production in China. We find that given projected increases in O 3 concentrations in the region, East Asian countries are presently on the cusp of substantial reductions in grain production. Our conservative estimates, based on 7- and 12-h mean (M7 or M12) exposure indices, show that due to O 3 concentrations in 1990 China, Japan and South Korea lost 1-9% of their yield of wheat, rice and corn and 23-27% of their yield of soybeans, with an associated value of 1990US 3.5, 1.2 and 0.24 billion, respectively. In 2020, assuming no change in agricultural production practices and again using M7 and M12 exposure indices, grain loss due to increased levels of O 3 pollution is projected to increase to 2-16% for wheat, rice and corn and 28-35% for soybeans; the associated economic costs are expected to increase by 82%, 33%, and 67% in 2020 over 1990 for China, Japan and South Korea, respectively. For most crops, the yield losses in 1990 based on SUM06 or W126 exposure indices are lower than yield losses estimated using M7 or M12 exposure indices in China and Japan but higher in South Korea; in 2020, the yield losses based on SUM06 or W126 exposure indices are substantially higher for all crops in all three countries. This is primarily due to the nature of the cumulative indices which weight elevated values of O 3 more heavily than lower values. Chinese compliance with its ambient O 3 standard in 1990 would have had a limited effect in reducing the grain yield loss caused by O 3 exposure, resulting in only US 0.2 billion of additional grain revenues, but in 2020 compliance could reduce the yield loss by one third and lead to an increase of US$ 2.6 (M7 or M12) -27 (SUM06) billion in grain revenues. We conclude that East Asian countries may have tremendous losses of crop yields in the near future due to projected increases in O 3 concentrations. They likely could achieve substantial increases in future agricultural production through reduction of surface O 3 concentrations and/or use of O 3 resistant crop cultivars.

UNDERSTANDING AND MANAGING THE HEALTH AND ENVIRONMENTAL RISKS RESULTING FROM GLOBAL ATMOSPHERIC CHANGE FROM RECOGNITION OF POTENTIAL PROBLEMS TO CONCRETE MITIGATIVE ACTIONS

EPA Science Inventory

As a consequence of anthropogenic activities, we may double the pre-industrial concentration of atmospheric CO2 by the middle of this century. Anthropogenic activities have already doubled the amount of fixed nitrogen that cycles the globe, substantially increasing the flux of re...

Quantifying the impact of current and future concentrations of air pollutants on respiratory disease risk in England.

PubMed

Pannullo, Francesca; Lee, Duncan; Neal, Lucy; Dalvi, Mohit; Agnew, Paul; O'Connor, Fiona M; Mukhopadhyay, Sabyasachi; Sahu, Sujit; Sarran, Christophe

2017-03-27

Estimating the long-term health impact of air pollution in a spatio-temporal ecological study requires representative concentrations of air pollutants to be constructed for each geographical unit and time period. Averaging concentrations in space and time is commonly carried out, but little is known about how robust the estimated health effects are to different aggregation functions. A second under researched question is what impact air pollution is likely to have in the future. We conducted a study for England between 2007 and 2011, investigating the relationship between respiratory hospital admissions and different pollutants: nitrogen dioxide (NO 2 ); ozone (O 3 ); particulate matter, the latter including particles with an aerodynamic diameter less than 2.5 micrometers (PM 2.5 ), and less than 10 micrometers (PM 10 ); and sulphur dioxide (SO 2 ). Bayesian Poisson regression models accounting for localised spatio-temporal autocorrelation were used to estimate the relative risks (RRs) of pollution on disease risk, and for each pollutant four representative concentrations were constructed using combinations of spatial and temporal averages and maximums. The estimated RRs were then used to make projections of the numbers of likely respiratory hospital admissions in the 2050s attributable to air pollution, based on emission projections from a number of Representative Concentration Pathways (RCP). NO 2 exhibited the largest association with respiratory hospital admissions out of the pollutants considered, with estimated increased risks of between 0.9 and 1.6% for a one standard deviation increase in concentrations. In the future the projected numbers of respiratory hospital admissions attributable to NO 2 in the 2050s are lower than present day rates under 3 Representative Concentration Pathways (RCPs): 2.6, 6.0, and 8.5, which is due to projected reductions in future NO 2 emissions and concentrations. NO 2 concentrations exhibit consistent substantial present-day health effects regardless of how a representative concentration is constructed in space and time. Thus as concentrations are predicted to remain above limits set by European Union Legislation until the 2030s in parts of urban England, it will remain a substantial health risk for some time.

The effect of ethylene glycol on pore arrangement of anodic aluminium oxide prepared by hard anodization.

PubMed

Guo, Yang; Zhang, Li; Han, Mangui; Wang, Xin; Xie, Jianliang; Deng, Longjiang

2018-03-01

The influence of the addition of ethylene glycol (EG) on the pore self-ordering process in anodic aluminium oxide (AAO) membranes prepared by hard anodization (HA) was investigated. It was illustrated that EG has a substantial effect on the pore arrangement of AAO, and it was found that a smaller pore size can be obtained with an EG concentration reaching 20 wt% in aqueous electrolyte. The number of estimated defects of AAO increases significantly with an increase in EG concentration to 50 wt%. Excellent ordering of pores was realized when the samples were anodized in the 30 wt%-EG-containing aqueous electrolyte.

The effect of ethylene glycol on pore arrangement of anodic aluminium oxide prepared by hard anodization

PubMed Central

Zhang, Li; Han, Mangui; Wang, Xin; Xie, Jianliang; Deng, Longjiang

2018-01-01

The influence of the addition of ethylene glycol (EG) on the pore self-ordering process in anodic aluminium oxide (AAO) membranes prepared by hard anodization (HA) was investigated. It was illustrated that EG has a substantial effect on the pore arrangement of AAO, and it was found that a smaller pore size can be obtained with an EG concentration reaching 20 wt% in aqueous electrolyte. The number of estimated defects of AAO increases significantly with an increase in EG concentration to 50 wt%. Excellent ordering of pores was realized when the samples were anodized in the 30 wt%-EG-containing aqueous electrolyte. PMID:29657754

Long term measurements of light absorbing particles on tropical glaciers

NASA Astrophysics Data System (ADS)

Schmitt, C. G.; Sanchez Rodriguez, W.; Arnott, W. P.; All, J.; Schwarz, J. P.

2016-12-01

We present results of six years of measurements of light absorbing particles (LAP) on glaciers of the Cordillera Blanca mountain range in Peru. Tropical glaciers are important sources of water for human consumption, agriculture, and hydroelectric power in the region. Regular measurements in the dry season show that light absorbing particle concentrations are generally low (equivalent to the absorption equivalent of 5-30 nanograms of black carbon per gram of snow) during non-El Nino years while values increase substantially during the recent El Nino. Two years of monthly measurements at two glaciers show that fresh snow LAP concentration are very low while LAP levels increase dramatically during snow-less periods.

The effect of changes in space shuttle parameters on the NASA/MSFC multilayer diffusion model predictions of surface HCl concentrations

NASA Technical Reports Server (NTRS)

Glasser, M. E.; Rundel, R. D.

1978-01-01

A method for formulating these changes into the model input parameters using a preprocessor program run on a programed data processor was implemented. The results indicate that any changes in the input parameters are small enough to be negligible in comparison to meteorological inputs and the limitations of the model and that such changes will not substantially increase the number of meteorological cases for which the model will predict surface hydrogen chloride concentrations exceeding public safety levels.

The biogeochemical effect of seaweeds upon close-to natural concentrations of dissolved iodate and iodide in seawater Preliminary study with Laminaria digitata and Fucus serratus

NASA Astrophysics Data System (ADS)

Truesdale, Victor W.

2008-06-01

Toward assessing the biogeochemical significance of seaweeds in relation to dissolved iodine in seawater, the effect of whole seaweeds ( Laminaria digitata and Fucus serratus) upon iodide and iodate, at essentially natural concentrations, has been studied. The weeds were carefully removed from the sub-littoral zone of the Menai Straits and exposed to iodide and iodate at their natural temperature (6 °C), but under continuous illumination. Laminaria digitata was found to decrease the concentration of iodate with an exponential rate constant of 0.008-0.24 h -1. This is a newly discovered process which, if substantiated, will require an entirely new mechanism. Generally, apparent iodide concentration increased except in a run with seawater augmented with iodide, where it first decreased. The rate constant for loss of iodide was 0.014-0.16 h -1. Meanwhile, F. serratus was found not to decrease iodate concentrations, as did L. digitata. Indeed, after ˜30 h iodate concentrations increased, suggesting that the weed may take in iodide before oxidising and releasing it. If substantiated, this finding may offer a way into one of the most elusive of processes within the iodine cycle - iodide oxidation. With both seaweeds sustained long-term increases of apparent iodide concentration are most easily explained as a secretion by the weeds of organic matter which is capable of reducing the Ce(IV) reagent used in determination of total iodine. Modelling of the catalytic method used is provided to support this contention. The possibility of developing this to measure the strain that seaweeds endure in this kind of biogeochemical flux experiment is discussed. A Chemical Oxygen Demand type of approach is applied using Ce(IV) as oxidant. The results of the iodine experiments are contrasted with the several investigations of 131I interaction with seaweeds, which have routinely used discs of weed cut from the frond. It is argued that experiments conducted with stable iodine may measure a different variable to that measured in radio-iodine experiments.

Elevation effects in volcano applications of the COSPEC

USGS Publications Warehouse

Gerlach, T.M.

2003-01-01

Volcano applications commonly involve sizeable departures from the reference pressure and temperature of COSPEC calibration cells. Analysis shows that COSPEC SO2 column abundances and derived mass emission rates are independent of pressure and temperature, and thus unaffected by elevation effects related to deviations from calibration cell reference state. However, path-length concentrations are pressure and temperature dependent. Since COSPEC path-length concentration data assume the reference pressure and temperature of calibration cells, they can lead to large errors when used to calculate SO2 mixing ratios of volcanic plumes. Correction factors for COSPEC path-length concentrations become significant (c.10%) at elevations of about 1 km (e.g. Kilauea volcano) and rise rapidly to c.80% at 6 km (e.g. Cotopaxi volcano). Calculating SO2 mixing ratios for volcanic plumes directly from COSPEC path-length concentrations always gives low results. Corrections can substantially increase mixing ratios; for example, corrections increase SO2 ppm concentrations reported for the Mount St Helens, Colima, and Erebus plumes by 25-50%. Several arguments suggest it would be advantageous to calibrate COSPEC measurements in column abundance units rather than path-length concentration units.

Metamorphosis affects metal concentrations and isotopic signatures in a mayfly (Baetis tricaudatus): Implications for the aquatic-terrestrial transfer of metals

USGS Publications Warehouse

Wesner, Jeff S.; Walters, David; Schmidt, Travis S.; Kraus, Johanna M.; Stricker, Craig A.; Clements, William H.; Wolf, Ruth E.

2017-01-01

Insect metamorphosis often results in substantial chemical changes that can alter contaminant concentrations and fractionate isotopes. We exposed larval mayflies (Baetis tricaudatus) and their food (periphyton) to an aqueous zinc gradient (3-340 µg Zn/l) and measured zinc concentrations at different stages of metamorphosis: larval, subimago, and imago. We also measured changes in stable isotopes (δ15N and δ13C) in unexposed mayflies. Larval zinc concentrations were positively related to aqueous zinc, increasing 9-fold across the exposure gradient. Adult zinc concentrations were also positively related to aqueous zinc, but were 7-fold lower than larvae. This relationship varied according to adult substage and sex. Tissue concentrations in female imagoes were not related to exposure concentrations, but the converse was true for all other stage-by-sex combinations. Metamorphosis also increased δ15N by ~0.8‰, but not δ13C. Thus, the main effects of metamorphosis on insect chemistry were large declines in zinc concentrations coupled with increased δ15N signatures. For zinc, this change was largely consistent across the aqueous exposure gradient. However, differences among sexes and stages suggest that caution is warranted when using nitrogen isotopes or metal concentrations measured in one insect stage (e.g. larvae) to assess risk to wildlife that feed on subsequent life stages (e.g. adults).

Metamorphosis Affects Metal Concentrations and Isotopic Signatures in a Mayfly (Baetis tricaudatus): Implications for the Aquatic-Terrestrial Transfer of Metals.

PubMed

Wesner, Jeff S; Walters, David M; Schmidt, Travis S; Kraus, Johanna M; Stricker, Craig A; Clements, William H; Wolf, Ruth E

2017-02-21

Insect metamorphosis often results in substantial chemical changes that can alter contaminant concentrations and fractionate isotopes. We exposed larval mayflies (Baetis tricaudatus) and their food (periphyton) to an aqueous zinc gradient (3-340 μg Zn/l) and measured zinc concentrations at different stages of metamorphosis: larval, subimago, and imago. We also measured changes in stable isotopes (δ 15 N and δ 13 C) in unexposed mayflies. Larval zinc concentrations were positively related to aqueous zinc, increasing 9-fold across the exposure gradient. Adult zinc concentrations were also positively related to aqueous zinc, but were 7-fold lower than larvae. This relationship varied according to adult substage and sex. Tissue concentrations in female imagoes were not related to exposure concentrations, but the converse was true for all other stage-by-sex combinations. Metamorphosis also increased δ 15 N by ∼0.8‰, but not δ 13 C. Thus, the main effects of metamorphosis on insect chemistry were large declines in zinc concentrations coupled with increased δ 15 N signatures. For zinc, this change was largely consistent across the aqueous exposure gradient. However, differences among sexes and stages suggest that caution is warranted when using nitrogen isotopes or metal concentrations measured in one insect stage (e.g., larvae) to assess risk to wildlife that feed on subsequent life stages (e.g., adults).

Disparity in disinfection byproducts concentration between hot and cold tap water.

PubMed

Liu, Boning; Reckhow, David A

2015-03-01

The quality of water entering a distribution system may differ substantially from the quality at the point of exposure to the consumer. This study investigated temporal variations in the levels of regulated and non-regulated disinfection byproducts (DBPs) in cold and hot tap water in a home on a medium-sized municipal water system. In addition, samples were collected directly from the water plant with some being held in accordance with a simulated distribution system (SDS) test protocol. The location for this work was a system in western Massachusetts, USA that uses free chlorine as a final disinfectant. Very little short term variability of DBPs at the point of entry (POE) was observed. The concentration of DBPs in the time-variable SDS test was similar to concentrations in the cold water tap. For most DBPs, the concentrations continued to increase as the cold water tap sample was held for the time-variable SDS incubation period. However, the impact of heating on DBP levels was compound specific. For example, the concentrations of trihalomethanes (THMs), dichloroacetic acid (DCAA) and chloropicrin (CP) were substantially higher in the hot water tap than in the cold water time-variable SDS samples. In contrast, the concentration of trichloroacetic acid (TCAA) was lower in the heated hot tap water, but about equal to that observed in the cold tap water. The situation was more pronounced for dichloroacetonitrile (DCAN), bromodichloroacetic acid (BDCAA), bromochloroacetic acid (BCAA) and 1,1,1-trichloropropanone (TCP), which all showed lower concentrations in the hot water then in either of the cold water samples (instantaneous or time-variable SDS). The latter was viewed as a clear indication of thermally-induced decomposition. The ratio of unknown total organic halide (UTOX) to TOX was substantially lower in the hot tap water as the THM to TOX ratio became correspondingly larger. The results of this study show that DBP exposure in the home is not well represented by concentrations measured in cold water taps where most compliance monitoring is done. Copyright © 2014 Elsevier Ltd. All rights reserved.

Reconnaissance of water quality of Pueblo Reservoir, Colorado: May through December 1985

USGS Publications Warehouse

Edelmann, Patrick

1989-01-01

Pueblo Reservoir is the farthest upstream, main-stream reservoir constructed on the Arkansas River and is located in Pueblo County approximately 6 miles upstream from the city of Pueblo, Colorado. During the 1985 sampling period, the reservoir was stratified, and underflow from the Arkansas River occurred that resulted in stratification with respect to specific conductance. Concentrations of dissolved solids decreased markedly below the thermocline during June. Later in the summer, dissolved-solids concentrations increased substantially below the thermocline. Substantial depletion of dissolved oxygen occurred near the bottom of the reservoir. The dissolved oxygen minimum of 0.1 mg/L occurred during August near the reservoir bottom at transect 7 (near the dam). The average total-inorganic-nitrogen concentration near the reservoir surface was about 0.2 mg/L; near the reservoir bottom, the average concentration was about 0.3 mg/L. Concentrations of total phosphorus ranged from less than 0.01 to 0.05 mg/L near the reservoir surface, and from less than 0.01 to 0.22 mg/L near the reservoir bottom. At transect 2 (about 7 miles upstream from the dam) near the bottom of the reservoir, concentrations of total iron exceeded aquatic-life standards, and dissolved-manganese concentrations exceeded standards for public water supply. Diatoms, green algae, blue-green algae, and cryptomonads comprised the majority of phytoplankton in Pueblo Reservoir in 1985. The maximum average of 41,000 cells/ml occurred in July. Blue-green algae dominated from June to September; diatoms were the dominant group of algae in October. The average concentrations of phytoplankton decreased from July to October. (USGS)

Trends in Hospital Volume and Operative Mortality for High-Risk Surgery

PubMed Central

Finks, Jonathan F.; Osborne, Nicholas H.; Birkmeyer, John D.

2011-01-01

BACKGROUND There were numerous efforts in the United States during the previous decade to concentrate selected surgical procedures in high-volume hospitals. It remains unknown whether referral patterns for high-risk surgery have changed as a result and how operative mortality has been affected. METHODS We used national Medicare data to study patients undergoing one of eight different cancer and cardiovascular operations from 1999 through 2008. For each procedure, we examined trends in hospital volume and market concentration, defined as the proportion of Medicare patients undergoing surgery in the top decile of hospitals by volume per year. We used regression-based techniques to assess the effects of volume and market concentration on mortality over time, adjusting for case mix. RESULTS Median hospital volumes of four cancer resections (lung, esophagus, pancreas, and bladder) and of repair of abdominal aortic aneurysm (AAA) rose substantially. Depending on the procedure, higher hospital volumes were attributable to an increasing number of cases nationwide, an increasing market concentration, or both. Hospital volumes rose slightly for aortic-valve replacement but fell for coronary-artery bypass grafting and carotid endarterectomy. Operative mortality declined for all eight procedures, ranging from a relative decline of 8% for carotid endarterectomy (1.3% mortality in 1999 and 1.2% in 2008) to 36% for AAA repair (4.4% in 1999 and 2.8% in 2008). Higher hospital volumes explained a large portion of the decline in mortality for pancreatectomy (67% of the decline), cystectomy (37%), and esophagectomy (32%), but not for the other procedures. CONCLUSIONS Operative mortality with high-risk surgery fell substantially during the previous decade. Although increased market concentration and hospital volume have contributed to declining mortality with some high-risk cancer operations, declines in mortality with other procedures are largely attributable to other factors. (Funded by the National Institute on Aging.) PMID:21631325

Potential sea salt aerosol sources from frost flowers in the pan-Arctic region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Li; Russell, Lynn M.; Burrows, Susannah M.

In order to better represent observed wintertime aerosol concentrations at Barrow, Alaska, we implemented an observationally-based parameterization for estimating sea salt production from frost flowers in the Community Earth System Model (CESM). In this work, we evaluate the potential influence of this sea salt source on the pan-Arctic (60ºN-90ºN) climate. Results show that frost flower salt emissions substantially increase the modeled surface sea salt aerosol concentration in the winter months when new sea ice and frost flowers are present. The parameterization reproduces both the magnitude and seasonal variation of the observed submicron sea salt aerosol concentration at surface in Barrowmore » during winter much better than the standard CESM simulation without a frost-flower salt particle source. Adding these frost flower salt particle emissions increases aerosol optical depth by 10% and results in a small cooling at surface. The increase in salt particle mass concentrations of a factor of 8 provides nearly two times the cloud condensation nuclei concentration, as well as 10% increases in cloud droplet number and 40% increases in liquid water content near coastal regions adjacent to continents. These cloud changes reduce longwave cloud forcing by 3% and cause a small surface warming, increasing the downward longwave flux at the surface by 2 W m-2 in the pan-Arctic under the present-day climate.« less

Trends in the suspended-sediment yields of coastal rivers of northern California, 1955–2010

USGS Publications Warehouse

Warrick, J.A.; Madej, Mary Ann; Goñi, M. A.; Wheatcroft, R.A.

2013-01-01

Time-dependencies of suspended-sediment discharge from six coastal watersheds of northern California – Smith River, Klamath River, Trinity River, Redwood Creek, Mad River, and Eel River – were evaluated using monitoring data from 1955 to 2010. Suspended-sediment concentrations revealed time-dependent hysteresis and multi-year trends. The multi-year trends had two primary patterns relative to river discharge: (i) increases in concentration resulting from both land clearing from logging and the flood of record during December 1964 (water year 1965), and (ii) continual decreases in concentration during the decades following this flood. Data from the Eel River revealed that changes in suspended-sediment concentrations occurred for all grain-size fractions, but were most pronounced for the sand fraction. Because of these changes, the use of bulk discharge-concentration relationships (i.e., “sediment rating curves”) without time-dependencies in these relationships resulted in substantial errors in sediment load estimates, including 2.5-fold over-prediction of Eel River sediment loads since 1979. We conclude that sediment discharge and sediment discharge relationships (such as sediment rating curves) from these coastal rivers have varied substantially with time in response to land use and climate. Thus, the use of historical river sediment data and sediment rating curves without considerations for time-dependent trends may result in significant errors in sediment yield estimates from the globally-important steep, small watersheds.

Natural attenuation of chlorinated volatile organic compounds in ground water at Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington

USGS Publications Warehouse

Dinicola, Richard S.; Cox, S.E.; Landmeyer, J.E.; Bradley, P.M.

2002-01-01

The U.S. Geological Survey (USGS) evaluated the natural attenuation of chlorinated volatile organic compounds (CVOCs) in ground water beneath the former landfill at Operable Unit 1 (OU 1), Naval Undersea Warfare Center, Division Keyport, Washington. The predominant contaminants in ground water are trichloroethene (TCE) and its degradation byproducts cis-1,2-dichloroethene (cisDCE) and vinyl chloride (VC). The Navy planted two hybrid poplar plantations on the landfill in spring of 1999 to remove and control the migration of CVOCs in shallow ground water. Previous studies provided evidence that microbial degradation processes also reduce CVOC concentrations in ground water at OU 1, so monitored natural attenuation is a potential alternative remedy if phytoremediation is ineffective. This report describes the current (2000) understanding of natural attenuation of CVOCs in ground water at OU 1 and the impacts that phytoremediation activities to date have had on attenuation processes. The evaluation is based on ground-water and surface-water chemistry data and hydrogeologic data collected at the site by the USGS and Navy contractors between 1991 and 2000. Previously unpublished data collected by the USGS during 1996-2000 are presented. Natural attenuation of CVOCs in shallow ground water at OU 1 is substantial. For 1999-2000 conditions, approximately 70 percent of the mass of dissolved chlorinated ethenes that was available to migrate from the landfill was completely degraded in shallow ground water before it could migrate to the intermediate aquifer or discharge to surface water. Attenuation of CVOC concentrations appears also to be substantial in the intermediate aquifer, but biodegradation appears to be less significant; those conclusions are less certain because of the paucity of data downgradient of the landfill beneath the tide flats. Attenuation of CVOC concentrations is also substantial in surface water as it flows through the adjacent marsh and out to the tide flats. Attenuation processes other than dilution reduce the CVOC flux in marsh surface water by about 40 percent by the time the water discharges to the tide flats. Despite the importance of natural attenuation processes at reducing both the contaminant concentrations and the contaminant mass at OU 1, natural attenuation alone was not effective enough in the year 2000 to meet current numerical remediation goals for the site. That was in part due to the relatively short distance between the landfill and the adjacent marsh, and in part due to the extremely high CVOC concentrations directly beneath the landfill. Phytoremediation activities had some apparent effect on contaminant concentrations in ground water and surface water, but ground-water redox conditions to date (2000) were not affected by the February 1999 asphalt removal for tree planting. The poplar trees in the phytoremediation plantations were not yet mature in 2000, so the lack of discernible changes to date is understandable. Concentration changes of some redox-sensitive compounds suggest that increased recharge following asphalt removal diluted ambient landfill ground water. CVOC concentrations increased in some downgradient wells in both the northern and southern plantations after asphalt removal, whereas CVOC concentrations decreased in some upgradient wells in the southern plantation. A clear increase in CVOC concentrations in marsh surface water followed asphalt removal, apparently from increased contaminant discharge in ground water beneath the southern plantation. The results of the natural attenuation evaluation suggest than minor modifications to the current sampling plan may be beneficial to understanding the future impacts of phytoremediation and natural attenuation on the fate and distribution of CVOCs at OU 1.

Surface tension prevails over solute effect in organic-influenced cloud droplet activation.

PubMed

Ovadnevaite, Jurgita; Zuend, Andreas; Laaksonen, Ari; Sanchez, Kevin J; Roberts, Greg; Ceburnis, Darius; Decesari, Stefano; Rinaldi, Matteo; Hodas, Natasha; Facchini, Maria Cristina; Seinfeld, John H; O' Dowd, Colin

2017-06-29

The spontaneous growth of cloud condensation nuclei (CCN) into cloud droplets under supersaturated water vapour conditions is described by classic Köhler theory. This spontaneous activation of CCN depends on the interplay between the Raoult effect, whereby activation potential increases with decreasing water activity or increasing solute concentration, and the Kelvin effect, whereby activation potential decreases with decreasing droplet size or increases with decreasing surface tension, which is sensitive to surfactants. Surface tension lowering caused by organic surfactants, which diminishes the Kelvin effect, is expected to be negated by a concomitant reduction in the Raoult effect, driven by the displacement of surfactant molecules from the droplet bulk to the droplet-vapour interface. Here we present observational and theoretical evidence illustrating that, in ambient air, surface tension lowering can prevail over the reduction in the Raoult effect, leading to substantial increases in cloud droplet concentrations. We suggest that consideration of liquid-liquid phase separation, leading to complete or partial engulfing of a hygroscopic particle core by a hydrophobic organic-rich phase, can explain the lack of concomitant reduction of the Raoult effect, while maintaining substantial lowering of surface tension, even for partial surface coverage. Apart from the importance of particle size and composition in droplet activation, we show by observation and modelling that incorporation of phase-separation effects into activation thermodynamics can lead to a CCN number concentration that is up to ten times what is predicted by climate models, changing the properties of clouds. An adequate representation of the CCN activation process is essential to the prediction of clouds in climate models, and given the effect of clouds on the Earth's energy balance, improved prediction of aerosol-cloud-climate interactions is likely to result in improved assessments of future climate change.

Is Afro-American Studies Research in Jeopardy? A Review of Recent Trends in Federal Research Support.

ERIC Educational Resources Information Center

Tucker, M. Belinda

1984-01-01

An investigation of Federal funding for Afro-American related projects for 1978 through 1983 shows that, during this period, research in the areas where Afro-American research is overwhelmingly concentrated--the social sciences and the humanities--has not kept pace with the substantial increases apparent in the funding of research in the…

Effect of exogenous reductant on growth and iron mobilization from ferrihydrite by the Pseudomonas mendocina ymp strain.

PubMed

Dhungana, Suraj; Anthony, Charles R; Hersman, Larry E

2007-05-01

Growth of the Pseudomonas mendocina ymp strain on insoluble ferrihydrite is enhanced by exogenous reductants with concurrent increase in soluble iron concentrations. This shows that exogenous reductants play a substantial role in the overall microbial iron bioavailability. The exogenous reductants may work together with the siderophores, Fe-scavenging agents, to facilitate ferrihydrite dissolution.

Uncertainties in Carbon Dioxide Radiative Forcing in Atmospheric General Circulation Models

NASA Technical Reports Server (NTRS)

Cess, R. D.; Zhang, M.-H.; Potter, G. L.; Gates, W. L.; Taylor, K. E.; Barker, H. W.; Colman, R. A.; Fraser, J. R.; McAvaney, B. J.; Dazlich, D. A.;

The optimal atmospheric CO2 concentration for the growth of winter wheat (Triticum aestivum).

PubMed

Xu, Ming

2015-07-20

This study examined the optimal atmospheric CO2 concentration of the CO2 fertilization effect on the growth of winter wheat with growth chambers where the CO2 concentration was controlled at 400, 600, 800, 1000, and 1200 ppm respectively. I found that initial increase in atmospheric CO2 concentration dramatically enhanced winter wheat growth through the CO2 fertilization effect. However, this CO2 fertilization effect was substantially compromised with further increase in CO2 concentration, demonstrating an optimal CO2 concentration of 889.6, 909.4, and 894.2 ppm for aboveground, belowground, and total biomass, respectively, and 967.8 ppm for leaf photosynthesis. Also, high CO2 concentrations exceeding the optima not only reduced leaf stomatal density, length and conductance, but also changed the spatial distribution pattern of stomata on leaves. In addition, high CO2 concentration also decreased the maximum carboxylation rate (Vc(max)) and the maximum electron transport rate (J(max)) of leaf photosynthesis. However, the high CO2 concentration had little effect on leaf length and plant height. The optimal CO2 fertilization effect found in this study can be used as an indicator in selecting and breeding new wheat strains in adapting to future high atmospheric CO2 concentrations and climate change. Copyright © 2015. Published by Elsevier GmbH.

Regulation of body metal concentrations: Toxicokinetics of cadmium and zinc in crickets.

PubMed

Bednarska, Agnieszka J; Opyd, Marta; Żurawicz, Ewelina; Laskowski, Ryszard

2015-09-01

Previous studies indicated that essential and xenobiotic metals differ substantially in terms of their toxicokinetics. Whether these differences are due to different assimilation rates, different elimination rates, or both, and whether all metals are regulated in a similar manner but with different efficiency remains unclear. To compare the mechanisms responsible for the regulation of different metals, parameters for toxicokinetic models have to be tested under exposures to the identical molar concentration of those metals. In this study, the cricket Gryllus assimilis was exposed to Zn or Cd at 2.5, 10, and 40mMkg(-1) dry food. The body concentrations of the metals were not perfectly regulated by the crickets. For Zn, a clear increase in the body concentration was found only at the highest treatment; whereas at the lowest treatment, the internal concentration remained unchanged throughout the experiment. At the lowest Zn concentration, the assimilation (kA) [day(-1)] and elimination (kE) [day(-1)] rate constants were balanced (kA=0.024, kE=0.024). When increasing the Zn exposure, kA decreased to 0.018 at 10mMkg(-1) and 0.01 at 40mMkg(-1), and kE increased to 0.05 and 0.07, respectively. Therefore, the body concentration of Zn was regulated by simultaneously changing the assimilation and elimination rate. By contrast, even at the lowest treatment, a significant increase in Cd concentration was observed in the crickets. The equilibrium Cd concentration resulted almost exclusively from increasing kE from 0.17, through 0.28 to 0.61 at 2.5, 10 and 40mMkg(-1). The kA for Cd did not reveal any clear trend. Zn was more efficiently regulated by crickets than was Cd: a 16-fold increase in exposure concentration (from 2.5 to 40mM Znkg(-1)) resulted only in a twofold increase of internal concentration, whereas the identical increase in Cd exposure concentration resulted in almost a sevenfold increase in internal concentration of this metal. Copyright © 2015 Elsevier Inc. All rights reserved.

Impacts of enhanced fertilizer applications on tropospheric ozone and crop damage over sub-Saharan Africa

NASA Astrophysics Data System (ADS)

Huang, Yaoxian; Hickman, Jonathan E.; Wu, Shiliang

2018-05-01

Fertilizer-induced nitrogen oxides (NOx) emissions in sub-Saharan Africa are expected to increase substantially in the coming decades, driven by increasing application of fertilizers to increase crop yields in an effort to attain food security across the continent. In many parts of sub-Saharan Africa, surface ozone (O3) is sensitive to increasing atmospheric concentrations of NOx. In this study, we employ the GEOS-Chem chemical transport model to conduct a preliminary investigation of the impacts on O3 air quality and the consequential crop damage associated with increasing fertilizer-induced NOx emissions in sub-Saharan Africa. Our simulation results, constrained by field NO flux measurements for the years 2011 and 2012 in response to a variety of fertilizer application rates in western Kenya, show that the enhancements in NO flux with fertilizer application rate of 150 kg N ha-1 can increase surface NOx and O3 concentrations by up to 0.36 and 2.8 ppbv respectively during the growing season. At the same time, accumulated O3 exposure during the crop growing season (expressed as AOT40 values) could increase by up to 496 ppb h, leading to crop yield decline of about 0.8% for O3-sensitive crops. Our results suggest that, when accounting for the consequential impacts on surface O3 air quality and crop damage over sub-Saharan Africa, agricultural intensification is possible without substantial impacts on crop productivity because the relatively small decline of crop yield resulting from O3 damage appears unlikely to outweigh the gain in crop yield from fertilization.

Explanation of inequality in utilization of ambulatory care before and after universal health insurance in Thailand

PubMed Central

Yiengprugsawan, V; Carmichael, GA; Lim, LL-Y; Seubsman, S; Sleigh, AC

2011-01-01

Thailand implemented a Universal Coverage Scheme (UCS) of national health insurance in April 2001 to finance equitable access to health care. This paper compares inequalities in health service use before and after the UCS, and analyses the trend and determinants of inequality. The national Health and Welfare Surveys of 2001 and 2005 are used for this study. The concentration index for use of ambulatory care among the population reporting a recent illness is used as a measure of health inequality, decomposed into contributing demographic, socio-economic, geographic and health insurance determinants. As a result of the UCS, the uninsured group fell from 24% in 2001 to 3% in 2005 and health service patterns changed. Use of public primary health care facilities such as health centres became more concentrated among the poor, while use of provincial/general hospitals became more concentrated among the better-off. Decomposition analysis shows that the increasingly common use of health centres among the poor in 2005 was substantially associated with those with lower income, residence in the rural northeast and the introduction of the UCS. The increasing use of provincial/general hospitals and private clinics among the better-off in 2005 was substantially associated with the government and private employee insurance schemes. Although the UCS scheme has achieved its objective in increasing insurance coverage and utilization of primary health services, our findings point to the need for future policies to focus on the quality of this primary care and equitable referrals to secondary and tertiary health facilities when required. PMID:20736414

Secondary organic aerosol formation through fog processing of VOCs

NASA Astrophysics Data System (ADS)

Herckes, P.; Hutchings, J. W.

2010-07-01

Volatile Organic Compounds (VOCs) including benzene, toluene, ethylbenzene and xylenes (BTEX) have been determined in highly concentrated amounts (>1 ug/L) in intercepted clouds in northern Arizona (USA). These VOCs are found in concentrations much higher than predicted by partitioning alone. The reactivity of BTEX in the fog/cloud aqueous phase was investigated through laboratory studies. BTEX species showed fast degradation in the aqueous phase in the presence of peroxides and light. Observed half-lives ranged from three and six hours, substantially shorter than the respective gas phase half-lives (several days). The observed reaction rates were on the order of 1 ppb/min but decreased substantially with increasing concentrations of organic matter (TOC). The products of BTEX oxidation reactions were analyzed using HPLC-UV and LCMS. The first generation of products identified included phenol and cresols which correspond to the hydroxyl-addition reaction to benzene and toluene. Upon investigating of multi-generational products, smaller, less volatile species are predominant although a large variety of products is found. Most reaction products have substantially lower vapor pressure and will remain in the particle phase upon droplet evaporation. The SOA generation potential of cloud and fog processing of BTEX was evaluated using simple calculations and showed that in ideal situations these reactions could add up to 9% of the ambient aerosol mass. In more conservative scenarios, the contribution of the processing of BTEX was around 1% of ambient aerosol concentrations. Overall, cloud processing of VOC has the potential to contribute to the atmospheric aerosol mass. However, the contribution will depend upon many factors such as the irradiation, organic matter content in the droplets and droplet lifetime.

Water quality in Indiana: trends in concentrations of selected nutrients, metals, and ions in streams, 2000-10

USGS Publications Warehouse

Risch, Martin R.; Bunch, Aubrey R.; Vecchia, Aldo V.; Martin, Jeffrey D.; Baker, Nancy T.

2014-01-01

Statistically significant trends were identified that included 167 downward trends and 83 upward trends. The Kankakee River Basin had the most significant upward trends while the most significant downward trends were in the Whitewater River Basin, the Lake Michigan Basin, and the Patoka River Basin. For most constituents, a majority of sites had significant downward trends. Two streams in the Lake Michigan Basin have shown substantial decreases in most constituents. The West Fork White River near Indianapolis, Indiana, showed increases in nitrate and phosphorus and the Kankakee River Basin showed increases in copper, zinc, chloride, sulfate, and hardness. Upward trends in nutrients were identified at a few sites, but most nutrient trends were downward. Upward trends in metals corresponded with relatively small concentration increases while downward trends involved considerably larger concentration changes. Downward trends in chloride, sulfate, and suspended solids were observed statewide, but upward trends in hardness were observed in the northern half of Indiana.

Mechanism of influence water vapor on combustion characteristics of propane-air mixture

NASA Astrophysics Data System (ADS)

Larionov, V. M.; Mitrofanov, G. A.; Sachovskii, A. V.; Kozar, N. K.

2016-01-01

The article discusses the results of an experimental study of the effect of water vapor at the flame temperature. Propane-butane mixture with air is burning on a modified Bunsen burner. Steam temperature was varied from 180 to 260 degrees. Combustion parameters changed by steam temperature and its proportion in the mixture with the fuel. The fuel-air mixture is burned in the excess air ratio of 0.1. It has been established that the injection of steam changes the characteristics of combustion fuel-air mixture and increase the combustion temperature. The concentration of CO in the combustion products is substantially reduced. Raising the temperature in the combustion zone is associated with increased enthalpy of the fuel by the added steam enthalpy. Reducing the concentration of CO is caused by decrease in the average temperature in the combustion zone by applying steam. Concentration of active hydrogen radicals and oxygen increases in the combustion zone. That has a positive effect on the process of combustion.

Pulsed corona discharge oxidation of aqueous lignin: decomposition and aldehydes formation.

PubMed

Panorel, Iris; Kaijanen, Laura; Kornev, Iakov; Preis, Sergei; Louhi-Kultanen, Marjatta; Sirén, Heli

2014-01-01

Lignin is the mass waste product of pulp and paper industry mostly incinerated for energy recovery. Lignin is, however, a substantial source of raw material for derivatives currently produced in costly wet oxidation processes. The pulsed corona discharge (PCD) for the first time was applied to lignin oxidation aiming a cost-effective environmentally friendly lignin removal and transformation to aldehydes. The experimental research into treatment of coniferous kraft lignin aqueous solutions was undertaken to establish the dependence of lignin oxidation and aldehyde formation on the discharge parameters, initial concentration of lignin and gas phase composition. The rate and the energy efficiency of lignin oxidation increased with increasing oxygen concentration reaching up to 82 g kW-1 h-1 in 89% vol. oxygen. Oxidation energy efficiency in PCD treatment exceeds the one for conventional ozonation by the factor of two under the experimental conditions. Oxidation at low oxygen concentrations showed a tendency of the increasing aldehydes and glyoxylic acid formation yield.

High strength graphite and method for preparing same

DOEpatents

Overholser, Lyle G.; Masters, David R.; Napier, John M.

1976-01-01

High strength graphite is manufactured from a mixture of a particulate filler prepared by treating a particulate carbon precursor at a temperature in the range of about 400.degree. to 1000.degree. C., an organic carbonizable binder, and green carbonizable fibers in a concentration of not more than 2 weight per cent of the filler. The use of the relatively small quantity of green fibers provides a substantial increase in the flexural strength of the graphite with only a relatively negligible increase in the modulus of elasticity.

Influence of chemical disorder on energy dissipation and defect evolution in concentrated solid solution alloys

PubMed Central

Zhang, Yanwen; Stocks, G. Malcolm; Jin, Ke; Lu, Chenyang; Bei, Hongbin; Sales, Brian C.; Wang, Lumin; Béland, Laurent K.; Stoller, Roger E.; Samolyuk, German D.; Caro, Magdalena; Caro, Alfredo; Weber, William J.

2015-01-01

A grand challenge in materials research is to understand complex electronic correlation and non-equilibrium atomic interactions, and how such intrinsic properties and dynamic processes affect energy transfer and defect evolution in irradiated materials. Here we report that chemical disorder, with an increasing number of principal elements and/or altered concentrations of specific elements, in single-phase concentrated solid solution alloys can lead to substantial reduction in electron mean free path and orders of magnitude decrease in electrical and thermal conductivity. The subsequently slow energy dissipation affects defect dynamics at the early stages, and consequentially may result in less deleterious defects. Suppressed damage accumulation with increasing chemical disorder from pure nickel to binary and to more complex quaternary solid solutions is observed. Understanding and controlling energy dissipation and defect dynamics by altering alloy complexity may pave the way for new design principles of radiation-tolerant structural alloys for energy applications. PMID:26507943

Metal pollution in Spanish terrestrial ecosystems during the twentieth century.

PubMed

Peñuelas, Josep; Filella, Iolanda

2002-01-01

We show here additional biological evidence of the alteration in global biogeochemistry by human activities during the twentieth century. The mineral concentration of herbarium specimens of 24 species of vascular plants and three species of bryophytes collected in North and East regions of Spain have substantially changed throughout the twentieth century. While V, a proxy tracer of oil pollution, exponentially increased in the last decades, other metals such as Cr, Ba, Sr, Al, Fe, Pb, Cd and Ti increased up to 1960-1970 and started to decrease in 1985-1995, when environmental legal regulations started to be effective. Multivariate principal component analysis showed an overall change in plant elemental concentrations throughout the different decades of the century and a clear separation of vascular plants and bryophytes. Likely important consequences for ecosystem structure and functioning and even for human health may be expected from these changes in mineral concentration.

Increased glutamate/GABA+ ratio in a shared autistic and schizotypal trait phenotype termed Social Disorganisation.

PubMed

Ford, Talitha C; Nibbs, Richard; Crewther, David P

2017-01-01

Autism and schizophrenia are multi-dimensional spectrum disorders that have substantial phenotypic overlap. This overlap is readily identified in the non-clinical population, and has been conceptualised as Social Disorganisation (SD). This study investigates the balance of excitatory glutamate and inhibitory γ -aminobutyric acid (GABA) concentrations in a non-clinical sample with high and low trait SD, as glutamate and GABA abnormalities are reported across the autism and schizophrenia spectrum disorders. Participants were 18 low (10 females) and 19 high (9 females) SD scorers aged 18 to 40 years who underwent 1 H-MRS for glutamate and GABA+macromolecule (GABA+) concentrations in right and left hemisphere superior temporal (ST) voxels. Reduced GABA+ concentration ( p  = 0.03) and increased glutamate/GABA+ ratio ( p  = 0.003) in the right ST voxel for the high SD group was found, and there was increased GABA+ concentration in the left compared to right ST voxel ( p  = 0.047). Bilateral glutamate concentration was increased for the high SD group ( p  = 0.006); there was no hemisphere by group interaction ( p  = 0.772). Results suggest that a higher expression of the SD phenotype may be associated with increased glutamate/GABA+ ratio in the right ST region, which may affect speech prosody processing, and lead behavioural characteristics that are shared within the autistic and schizotypal spectra.

Urea-Induced Unfolding of the Immunity Protein Im9 Monitored by spFRET

PubMed Central

Tezuka-Kawakami, Tomoko; Gell, Chris; Brockwell, David J.; Radford, Sheena E.; Smith, D. Alastair

2006-01-01

We have studied the urea-induced unfolding of the E colicin immunity protein Im9 using diffusion single-pair fluorescence resonance energy transfer. Detailed examination of the proximity ratio of the native and denatured molecules over a wide range of urea concentrations suggests that the conformational properties of both species are denaturant-dependent. Whereas native molecules become gradually more expanded as urea concentration increases, denatured molecules show a dramatic dependence of the relationship between proximity ratio and denaturant concentration, consistent with substantial compaction of the denatured ensemble at low denaturant concentrations. Analysis of the widths of the proximity ratio distributions for each state suggests that whereas the native state ensemble is relatively narrow and homogeneous, the denatured state may possess heterogeneity in mildly denaturing conditions. PMID:16798813

Polyfunctional dispersants for controlling viscosity of phyllosilicates

DOEpatents

Chaiko, David J.

2006-07-25

This invention provides phyllosilicates and polyfunctional dispersants which can be manipulated to selectively control the viscosity of phyllosilicate slurries. The polyfunctional dispersants used in the present invention, which include at least three functional groups, increase the dispersion and exfoliation of phyllosilicates in polymers and, when used in conjunction with phyllosilicate slurries, significantly reduce the viscosity of slurries having high concentrations of phyllosilicates. The functional groups of the polyfunctional dispersants are capable of associating with multivalent metal cations and low molecular weight organic polymers, which can be manipulated to substantially increase or decrease the viscosity of the slurry in a concentration dependent manner. The polyfunctional dispersants of the present invention can also impart desirable properties on the phyllosilicate dispersions including corrosion inhibition and enhanced exfoliation of the phyllosilicate platelets.

Effects of SO/sub 2/ torch gas additions on GTA weld shape

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heiple, C.R.; Burgardt, P.

1984-01-01

Small additions of sulfur or oxygen to the GTA weld pool in steels with low weld d/w (depth/width) ratios substantially increases the weld d/w ratio and furthermore the improved weld d/w ratio is largely independent of reasonable variations in base metal sulfur and oxygen content. The addition of small concentrations of SO/sub 2/ to the normal argon shielding gas is a simple and effective way to add sulfur to the weld pool and increase weld d/w ratio. Autogenous bead-on-plate welds under otherwise identical welding conditions were made on stainless steel plate with SO/sub 2/ concentrations in the torch gas rangingmore » between 0 and 2000 ppM.« less

The increasing threat to stratospheric ozone from dichloromethane.

PubMed

Hossaini, Ryan; Chipperfield, Martyn P; Montzka, Stephen A; Leeson, Amber A; Dhomse, Sandip S; Pyle, John A

2017-06-27

It is well established that anthropogenic chlorine-containing chemicals contribute to ozone layer depletion. The successful implementation of the Montreal Protocol has led to reductions in the atmospheric concentration of many ozone-depleting gases, such as chlorofluorocarbons. As a consequence, stratospheric chlorine levels are declining and ozone is projected to return to levels observed pre-1980 later this century. However, recent observations show the atmospheric concentration of dichloromethane-an ozone-depleting gas not controlled by the Montreal Protocol-is increasing rapidly. Using atmospheric model simulations, we show that although currently modest, the impact of dichloromethane on ozone has increased markedly in recent years and if these increases continue into the future, the return of Antarctic ozone to pre-1980 levels could be substantially delayed. Sustained growth in dichloromethane would therefore offset some of the gains achieved by the Montreal Protocol, further delaying recovery of Earth's ozone layer.

The increasing threat to stratospheric ozone from dichloromethane

NASA Astrophysics Data System (ADS)

Hossaini, Ryan; Chipperfield, Martyn P.; Montzka, Stephen A.; Leeson, Amber A.; Dhomse, Sandip S.; Pyle, John A.

2017-06-01

It is well established that anthropogenic chlorine-containing chemicals contribute to ozone layer depletion. The successful implementation of the Montreal Protocol has led to reductions in the atmospheric concentration of many ozone-depleting gases, such as chlorofluorocarbons. As a consequence, stratospheric chlorine levels are declining and ozone is projected to return to levels observed pre-1980 later this century. However, recent observations show the atmospheric concentration of dichloromethane--an ozone-depleting gas not controlled by the Montreal Protocol--is increasing rapidly. Using atmospheric model simulations, we show that although currently modest, the impact of dichloromethane on ozone has increased markedly in recent years and if these increases continue into the future, the return of Antarctic ozone to pre-1980 levels could be substantially delayed. Sustained growth in dichloromethane would therefore offset some of the gains achieved by the Montreal Protocol, further delaying recovery of Earth's ozone layer.

Increased fluxes of shelf-derived materials to the central Arctic Ocean

PubMed Central

Kipp, Lauren E.; Charette, Matthew A.; Moore, Willard S.; Henderson, Paul B.; Rigor, Ignatius G.

2018-01-01

Rising temperatures in the Arctic Ocean region are responsible for changes such as reduced ice cover, permafrost thawing, and increased river discharge, which, together, alter nutrient and carbon cycles over the vast Arctic continental shelf. We show that the concentration of radium-228, sourced to seawater through sediment-water exchange processes, has increased substantially in surface waters of the central Arctic Ocean over the past decade. A mass balance model for 228Ra suggests that this increase is due to an intensification of shelf-derived material inputs to the central basin, a source that would also carry elevated concentrations of dissolved organic carbon and nutrients. Therefore, we suggest that significant changes in the nutrient, carbon, and trace metal balances of the Arctic Ocean are underway, with the potential to affect biological productivity and species assemblages in Arctic surface waters. PMID:29326980

Combination induction plasma tube and current concentrator for introducing a sample into a plasma

DOEpatents

Hull, Donald E.; Bieniewski, Thomas M.

1988-01-01

An induction plasma tube in combination with a current concentrator. The rent concentrator has a substantially cylindrical body having an open end and a partially closed end which defines an aperture. A first slot extends the longitudinal length of the cylindrical body and a second slot extends radially outward from the aperture. Together the first and second slots form a single L-shaped slot. The current concentrator is disposed within a volume bounded by an induction coil substantially along the axis thereof, and when power is applied to the induction coil a concentrated current is induced within the current concentrator aperture. The concentrator is moveable relative to the coil along the longitudinal axis of the coil to control the amount of current which is concentrated at the aperture.

Characterisation of Atherogenic Effects of Low Carbohydrate, High Protein Diet (LCHP) in ApoE/LDLR-/- Mice.

PubMed

Kostogrys, R B; Johann, C; Czyżyńska, I; Franczyk-Żarów, M; Drahun, A; Maślak, E; Jasztal, A; Gajda, M; Mateuszuk, Ł; Wrobel, T P; Baranska, M; Wybrańska, I; Jezkova, K; Nachtigal, P; Chlopicki, S

2015-08-01

Low Carbohydrate High Protein diet represents a popular strategy to achieve weight loss. The aim of this study was to characterize effects of low carbohydrate, high protein diet (LCHP) on atherosclerotic plaque development in brachiocephalic artery (BCA) in apoE/LDLR-/- mice and to elucidate mechanisms of proatherogenic effects of LCHP diet. Atherosclerosis plaques in brachiocephalic artery (BCA) as well as in aortic roots, lipoprotein profile, inflammation biomarkers, expression of SREBP-1 in the liver as well as mortality were analyzed in Control diet (AIN-93G) or LCHP (Low Carbohydrate High Protein) diet fed mice. Area of atherosclerotic plaques in aortic roots or BCA from LCHP diet fed mice was substantially increased as compared to mice fed control diet and was characterized by increased lipids and cholesterol contents (ORO staining, FT-IR analysis), increased macrophage infiltration (MOMA-2) and activity of MMPs (zymography). Pro-atherogenic phenotype of LCHP fed apoE/LDLR-/- mice was associated with increased plasma total cholesterol concentration, and in LDL and VLDL fractions, increased TG contents in VLDL, and a modest increase in plasma urea. LCHP diet increased SCD-1 index, activated SREBP-1 transcription factor in the liver and triggered acute phase response as evidence by an increased plasma concentration of haptoglobin, CRP or AGP. Finally, in long-term experiment survival of apoE/LDLR-/- mice fed LCHP diet was substantially reduced as compared to their counterparts fed control diet suggesting overall detrimental effects of LCHP diet on health. The pro-atherogenic effect of LCHP diet in apoE/LDLR-/- mice is associated with profound increase in LDL and VLDL cholesterol, VLDL triglicerides, liver SREBP-1 upregulation, and systemic inflammation.

Atmospheric methane at Cape Meares - Analysis of a high-resolution data base and its environmental implications

NASA Technical Reports Server (NTRS)

Khalil, M. A. K.; Rasmussen, R. A.; Moraes, F.

1993-01-01

Between 1979 and 1992 we took some 120,000 measurements of atmospheric methane at Cape Meares on the Oregon coast. The site is representative of methane concentrations in the northern latitudes (from 30 deg N to 90 deg N). The average concentration during the experiment was 1698 parts per billion by volume (ppbv). Methane concentration increased by 190 ppbv (or 11.9 percent) during the 13-year span of the experiment. The rate of increase was about 20 +/- 4 ppbv/yr in the first 2 yr and 10 +/- 2 ppbv/yr in the last 2 yr of the experiment, suggesting a substantial decline in the trend at northern middle and high latitudes. Prominent seasonal cycles were observed. During the year, the concentration stays more or less constant until May and then starts falling, reaching lowest levels in July and August, then rises rapidly to nearly maximum concentrations in October. Interannual variations with small amplitudes of 2-3 ppbv occur with periods of 1.4 and 6.5 yr.

Effect of autohydrolysis on the wettability, absorbility and further alkali impregnation of poplar wood chips.

PubMed

Xu, Ningpan; Liu, Wei; Hou, Qingxi; Wang, Peiyun; Yao, Zhirong

2016-09-01

Autohydrolysis with different severity factors was performed on poplar wood chips prior to pulping, and the wettability, absorbility and the following impregnation of NaOH solution for the poplar wood chips were then investigated. The results showed that after autohydrolysis pretreatment the porosity, shrinkage and fiber saturation point (FSP) of the poplar wood chips were increased, while the surface contact angle decreased as the severity factor was increased. The autohydrolyzed chips absorbed more NaOH in impregnation that resulted in a low NaOH concentration in the bulk impregnation liquor (i.e., the impregnation liquor outside wood chips), while the concentration in the entrapped liquor (i.e., the impregnation liquor inside wood chips) was increased. Autohydrolysis substantially improved the effectiveness of alkali impregnation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fluorescence properties of Schiff base - N,N‧-bis(salicylidene) - 1,2-Phenylenediamine in presence of bile acid host

NASA Astrophysics Data System (ADS)

Roy, Nayan; Paul, Pradip C.; Singh, T. Sanjoy

2015-05-01

Fluorescence properties of Schiff base - N,N‧-bis(salicylidene) - 1,2-phenylenediamine (LH2) is used to study the micelles formed by aggregation of different important bile acids like cholic acid, deoxycholic acid, chenodeoxycholic acid and glycocholic acid by steady state and picosecond time-resolved fluorescence spectroscopy. The fluorescence band intensity was found out to increase with concomitant red shift with gradual addition of different bile acids. Binding constant of the probe with different bile acids as well as critical micelle concentration was obtained from the variation of fluorescence intensity on increasing concentration of bile acids in the medium. The increase in fluorescence quantum yields, fluorescence decay times and substantial decrease in nonradiative decay rate constants in bile acids micellar environment points to the restricted motion of the fluorophore inside the micellar subdomains.

Dependence of mobility on the electron concentration upon scattering at polar optical phonons in A{sup III}–N nitrides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borisenko, S. I., E-mail: sib@tpu.ru

2016-04-15

The dependence of the effective relaxation time on the electron concentration in A{sup III}–N nitrides in the case of electron scattering at polar longitudinal optical phonons is calculated by the marching method. The method takes into account the inelasticity of electron scattering at polar optical phonons for nitrides in the zinc-blende approximation. The calculations show a substantial increase in mobility in samples with a degenerate electron gas, if screening of the long-range potential of polar longitudinal optical phonons is taken into account.

Remote analysis of biological invasion and biogeochemical change

PubMed Central

Asner, Gregory P.; Vitousek, Peter M.

2005-01-01

We used airborne imaging spectroscopy and photon transport modeling to determine how biological invasion altered the chemistry of forest canopies across a Hawaiian montane rain forest landscape. The nitrogen-fixing tree Myrica faya doubled canopy nitrogen concentrations and water content as it replaced native forest, whereas the understory herb Hedychium gardnerianum reduced nitrogen concentrations in the forest overstory and substantially increased aboveground water content. This remote sensing approach indicates the geographic extent, intensity, and biogeochemical impacts of two distinct invaders; its wider application could enhance the role of remote sensing in ecosystem analysis and management. PMID:15761055

SEPARATING HAFNIUM FROM ZIRCONIUM

DOEpatents

Lister, B.A.J.; Duncan, J.F.; Hutcheon, J.M.

1956-08-21

Substantially complete separation of zirconium from hafnium may be obtained by elution of ion exchange material, on which compounds of the elements are adsorbed, with an approximately normal solution of sulfuric acid. Preferably the acid concentration is between 0.8 N amd 1.2 N, amd should not exceed 1.5 N;. Increasing the concentration of sulfate ion in the eluting solution by addition of a soluble sulfate, such as sodium sulfate, has been found to be advantageous. The preferred ion exchange materials are sulfonated polystyrene resins such as Dowex 50,'' and are preferably arranged in a column through which the solutions are passed.

Effect of solubilizing agents on mupirocin loading into and release from PEGylated nanoliposomes.

PubMed

Cern, Ahuva; Nativ-Roth, Einat; Goldblum, Amiram; Barenholz, Yechezkel

2014-07-01

Mupirocin was identified by quantitative structure property relationship models as a good candidate for remote liposomal loading. Mupirocin is an antibiotic that is currently restricted to topical administration because of rapid hydrolysis in vivo to its inactive metabolite. Formulating mupirocin in PEGylated nanoliposomes may potentially expand its use to parenteral administration by protecting it from degradation in the circulation and target it (by the enhanced permeability effect) to the infected tissue. Mupirocin is slightly soluble in aqueous medium and its solubility can be increased using solubilizing agents. The effect of the solubilizing agents on mupirocin remote loading was studied when the solubilizing agents were added to the drug loading solution. Propylene glycol was found to increase mupirocin loading, whereas polyethylene glycol 400 showed no effect. Hydroxypropyl-β-cyclodextrin (HPCD) showed a concentration-dependent effect on mupirocin loading; using the optimal HPCD concentration increased loading, but higher concentrations inhibited it. The inclusion of HPCD in the liposome aqueous phase while forming the liposomes resulted in increased drug loading and substantially inhibited drug release in serum. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Carbon dioxide dynamics of combined crops of wheat, cowpea, pinto beans in the Laboratory Biosphere closed ecological system

NASA Astrophysics Data System (ADS)

Dempster, William F.; Nelson, M.; Silverstone, S.; Allen, J. P.

2009-04-01

A mixed crop consisting of cowpeas, pinto beans and Apogee ultra-dwarf wheat was grown in the Laboratory Biosphere, a 40 m 3 closed life system equipped with 12,000 W of high pressure sodium lamps over planting beds with 5.37 m 2 of soil. Similar to earlier reported experiments, the concentration of carbon dioxide initially increased to 7860 ppm at 10 days after planting due to soil respiration plus CO 2 contributed from researchers breathing while in the chamber for brief periods before plant growth became substantial. Carbon dioxide concentrations then fell rapidly as plant growth increased up to 29 days after planting and subsequently was maintained mostly in the range of about 200-3000 ppm (with a few excursions) by CO 2 injections to feed plant growth. Numerous analyses of rate of change of CO 2 concentration at many different concentrations and at many different days after planting reveal a strong dependence of fixation rates on CO 2 concentration. In the middle period of growth (days 31-61), fixation rates doubled for CO 2 at 450 ppm compared to 270 ppm, doubled again at 1000 ppm and increased a further 50% at 2000 ppm. High productivity from these crops and the increase of fixation rates with elevated CO 2 concentration supports the concept that enhanced CO 2 can be a useful strategy for remote life support systems. The data suggests avenues of investigation to understand the response of plant communities to increasing CO 2 concentrations in the Earth's atmosphere. Carbon balance accounting and evapotranspiration rates are included.

Monthly variability and possible sources of nitrate in ground water beneath mixed agricultural land use, Suwannee and Lafayette Counties, Florida

USGS Publications Warehouse

Katz, Brian G.; Böhlke, J.K.

2000-01-01

In an area of mixed agricultural land use in Suwannee and Lafayette Counties of northern Florida, water samples were collected monthly from 14 wells tapping the Upper Floridan aquifer during July 1998 through June 1999 to assess hydrologic and land-use factors affecting the variability in nitrate concentrations in ground water. Unusually high amounts of rainfall in September and October 1998 (43.5 centimeters total for both months) resulted in an increase in water levels in all wells in October 1998. This was followed by unusually low amounts of rainfall during November 1998 through May 1999, when rainfall was 40.7 centimeters below 30-year mean monthly values. The presence of karst features (sinkholes, springs, solution conduits) and the highly permeable sands that overlie the Upper Floridan aquifer provide for rapid movement of water containing elevated nitrate concentrations to the aquifer. Nitrate was the dominant form of nitrogen in ground water collected at all sites and nitrate concentrations ranged from less than 0.02 to 22 milligrams per liter (mg/L), as nitrogen. Water samples from most wells showed substantial monthly or seasonal fluctuations in nitrate concentrations. Generally, water samples from wells with nitrate concentrations higher than 10 mg/L showed the greatest amount of monthly fluctuation. For example, water samples from six of eight wells had monthly nitrate concentrations that varied by at least 5 mg/L during the study period. Water from most wells with lower nitrate concentrations (less than 6 mg/L) also showed large monthly fluctuations. For instance, nitrate concentrations in water from four sites showed monthly variations of more than 50 percent. Large fluctuations in nitrate concentrations likely result from seasonal agricultural practices (fertilizer application and animal waste spreading) at a particular site. For example, an increase in nitrate concentrations observed in water samples from seven sites in February or March 1999 most likely results from application of synthetic fertilizers during the late winter months. Lower nitrate concentrations were detected in water samples from five of eight wells sampled during high-flow conditions for the Suwannee River in March 1998 compared to low-flow conditions in November 1998. Evidence for reduction of nitrate due to denitrification reactions was observed at one site (AC-1), as indicated by elevated concentrations of nitrogen gas and a corresponding increase in nitrogen isotope (d15N-NO3) values with a decrease in nitrate concentrations. Denitrification is unlikely at other sites based on the presence of dissolved oxygen concentrations greater than 2 mg/L in ground water and no observed trend between nitrate concentrations and values d15N-NO3 values. Nitrate was the dominant nitrogen species in most monthly rainfall samples; however, ammonium concentrations were similar or greater than nitrate during November and December 1998. During February through May 1999, both nitrate and ammonium concentrations were substantially higher in monthly rainfall samples collected at the study area compared to mean monthly concentrations at the Bradford Forest site located east of the study area, which is part of the National Atmospheric Deposition Program/National Trends Network. Also, higher nitrogen deposition rates in the study area compared to those at Bradford Forest could indicate that substantial amounts of ammonia are volatilized from fertilizers and animal wastes, released to the atmosphere, and incorporated as nitrate and ammonium in rainfall deposited in the middle Suwannee River Basin. Ground-water samples from most sites had d15N-NO3 values that indicated a mixture of inorganic and organic sources of nitrogen, which corresponded to multiple land uses where both synthetic fertilizers and manure are used on fields near these sites. Distinct d15N-NO3 signatures, however, were observed at some sites. For example, water samples from areas of row-crop farmin

Global and regional ocean carbon uptake and climate change: sensitivity to a substantial mitigation scenario

NASA Astrophysics Data System (ADS)

Vichi, Marcello; Manzini, Elisa; Fogli, Pier Giuseppe; Alessandri, Andrea; Patara, Lavinia; Scoccimarro, Enrico; Masina, Simona; Navarra, Antonio

2011-11-01

Under future scenarios of business-as-usual emissions, the ocean storage of anthropogenic carbon is anticipated to decrease because of ocean chemistry constraints and positive feedbacks in the carbon-climate dynamics, whereas it is still unknown how the oceanic carbon cycle will respond to more substantial mitigation scenarios. To evaluate the natural system response to prescribed atmospheric "target" concentrations and assess the response of the ocean carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System Model that includes a fully coupled carbon cycle, forced in one case with a mitigation scenario and the other with the SRES A1B scenario. End of century ocean uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific Ocean and to lower values in the Atlantic. With A1B, the major ocean basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle models, while at the regional level the response is contrasting. The model indicates that the equatorial Pacific may increase the carbon uptake rates in both scenarios, owing to enhancement of the biological carbon pump evidenced by an increase in Net Community Production (NCP) following changes in the subsurface equatorial circulation and enhanced iron availability from extratropical regions. NCP is a proxy of the bulk organic carbon made available to the higher trophic levels and potentially exportable from the surface layers. The model results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic oceans is projected to be halved with respect to the current climate under a substantial mitigation scenario at the end of the twenty-first century. It is thus suggested that changes due to cumulative carbon emissions up to present and the projected concentration pathways of aerosol in the next decades control the evolution of surface ocean biogeochemistry in the second half of this century more than the specific pathways of atmospheric CO2 concentrations.

7 CFR 1710.112 - Loan feasibility.

Code of Federal Regulations, 2011 CFR

2011-01-01

... other energy sources to prevent substantial load loss while providing satisfactory service to its consumers. (4) Risks of possible loss of substantial loads from large consumers or from load concentrations in particular industries will not substantially impair loan feasibility. (5) Risks of loss of...

7 CFR 1710.112 - Loan feasibility.

Code of Federal Regulations, 2012 CFR

2012-01-01

... other energy sources to prevent substantial load loss while providing satisfactory service to its consumers. (4) Risks of possible loss of substantial loads from large consumers or from load concentrations in particular industries will not substantially impair loan feasibility. (5) Risks of loss of...

7 CFR 1710.112 - Loan feasibility.

Code of Federal Regulations, 2010 CFR

2010-01-01

... other energy sources to prevent substantial load loss while providing satisfactory service to its consumers. (4) Risks of possible loss of substantial loads from large consumers or from load concentrations in particular industries will not substantially impair loan feasibility. (5) Risks of loss of...

7 CFR 1710.112 - Loan feasibility.

Code of Federal Regulations, 2013 CFR

2013-01-01

... other energy sources to prevent substantial load loss while providing satisfactory service to its consumers. (4) Risks of possible loss of substantial loads from large consumers or from load concentrations in particular industries will not substantially impair loan feasibility. (5) Risks of loss of...

7 CFR 1710.112 - Loan feasibility.

Code of Federal Regulations, 2014 CFR

2014-01-01

... other energy sources to prevent substantial load loss while providing satisfactory service to its consumers. (4) Risks of possible loss of substantial loads from large consumers or from load concentrations in particular industries will not substantially impair loan feasibility. (5) Risks of loss of...

Effects of diesel exhaust aftertreatment devices on concentrations and size distribution of aerosols in underground mine air.

PubMed

Bugarski, Aleksandar D; Schnakenberg, George H; Hummer, Ion A; Cauda, Emanuele; Janisko, Samuel I; Patts, Larry D

2009-09-01

Three types of uncatalyzed diesel particulate filter (DPF) systems, three types of high-temperature disposable filter elements (DFEs), and one diesel oxidation catalytic converter (DOC) were evaluated in underground mine conditions for their effects on the concentrations and size distributions of diesel aerosols. Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. The DPF systems reduced total mass of aerosols in the mine air approximately 10-fold for light-load and 20-fold or more for high-load test conditions. The DFEs offered similar reductions in aerosol mass concentrations. The efficiency of the new DFEs significantly increased with accumulation of operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on performance of the filter element The effectiveness of DPFs and DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for both DPFs and DFEs when the engine was operated at high-load modes than at low-load modes. The effects of the DOC on mass and number concentrations of aerosols in mine air were relatively minor when compared to those of the DPF and DFE systems.

Development of an evaporation-based microfluidic sample concentrator

NASA Astrophysics Data System (ADS)

Sharma, Nigel R.; Lukyanov, Anatoly; Bardell, Ron L.; Seifried, Lynn; Shen, Mingchao

2008-02-01

MicroPlumbers Microsciences LLC, has developed a relatively simple concentrator device based on isothermal evaporation. The device allows for rapid concentration of dissolved or dispersed substances or microorganisms (e.g. bacteria, viruses, proteins, toxins, enzymes, antibodies, etc.) under conditions gentle enough to preserve their specific activity or viability. It is capable of removing of 0.8 ml of water per minute at 37°C, and has dimensions compatible with typical microfluidic devices. The concentrator can be used as a stand-alone device or integrated into various processes and analytical instruments, substantially increasing their sensitivity while decreasing processing time. The evaporative concentrator can find applications in many areas such as biothreat detection, environmental monitoring, forensic medicine, pathogen analysis, and agricultural industrial monitoring. In our presentation, we describe the design, fabrication, and testing of the concentrator. We discuss multiphysics simulations of the heat and mass transport in the device that we used to select the design of the concentrator and the protocol of performance testing. We present the results of experiments evaluating water removal performance.

Atmospheric dynamics of combined crops of wheat, cowpea, pinto beans in the Laboratory Biosphere closed ecological system

NASA Astrophysics Data System (ADS)

Dempster, W.; Nelson, M.; Silverstone, S.; Allen, J.; Alling, A.; van Thillo, M.

A mixed crop consisting of cowpeas pinto beans and Apogee ultra-dwarf wheat was grown in Laboratory Biosphere a 40 m 3 closed life system equipped with 12000 watts of high pressure sodium lamps over planting beds with 5 37 m 2 of soil Similar to earlier reported experiments the concentration of carbon dioxide initially increased to 7860 ppm at 10 days after planting due to soil respiration plus CO 2 contributed from researchers breathing while in the chamber for brief periods before plant growth became substantial fell rapidly as plant growth increased up to 29 days after planting and then was maintained mostly in the range of about 200 -- 3000 ppm with a few excursions by CO 2 injections to feed plant growth Numerous analyses of rate of change of CO 2 concentration at many different concentrations and at many different days after planting reveals a strong dependence of fixation rates on CO 2 concentration In the middle period of growth days 31 -- 61 fixation rates doubled for CO 2 at 450 ppm compared to 270 ppm doubled again at 1000 ppm and increased a further 50 at 2040 ppm High productivity from these crops and the increase of fixation rates with elevated CO 2 concentration supports the concept that enhanced CO2 can be a useful strategy for remote life support systems

Cannabis effects on driving skills.

PubMed

Hartman, Rebecca L; Huestis, Marilyn A

2013-03-01

Cannabis is the most prevalent illicit drug identified in impaired drivers. The effects of cannabis on driving continue to be debated, making prosecution and legislation difficult. Historically, delays in sample collection, evaluating the inactive Δ(9)-tetrahydrocannabinol (THC) metabolite 11-nor-9-carboxy-THC, and polydrug use have complicated epidemiologic evaluations of driver impairment after cannabis use. We review and evaluate the current literature on cannabis' effects on driving, highlighting the epidemiologic and experimental data. Epidemiologic data show that the risk of involvement in a motor vehicle accident (MVA) increases approximately 2-fold after cannabis smoking. The adjusted risk of driver culpability also increases substantially, particularly with increased blood THC concentrations. Studies that have used urine as the biological matrix have not shown an association between cannabis and crash risk. Experimental data show that drivers attempt to compensate by driving more slowly after smoking cannabis, but control deteriorates with increasing task complexity. Cannabis smoking increases lane weaving and impaired cognitive function. Critical-tracking tests, reaction times, divided-attention tasks, and lane-position variability all show cannabis-induced impairment. Despite purported tolerance in frequent smokers, complex tasks still show impairment. Combining cannabis with alcohol enhances impairment, especially lane weaving. Differences in study designs frequently account for inconsistencies in results between studies. Participant-selection bias and confounding factors attenuate ostensible cannabis effects, but the association with MVA often retains significance. Evidence suggests recent smoking and/or blood THC concentrations 2-5 ng/mL are associated with substantial driving impairment, particularly in occasional smokers. Future cannabis-and-driving research should emphasize challenging tasks, such as divided attention, and include occasional and chronic daily cannabis smokers.

EVALUATING THE EFFECTS OF NEAR ROAD SOLID AND ...

EPA Pesticide Factsheets

Public health concerns for populations living, working and going to school near high-traffic roadways has increased substantially in recent years. Air quality measurement studies indicate high pollutant concentrations can occur near these large roads, impacting population exposures and health effects. Roadside features have been shown to alter pollutant transport and dispersion from the road, affecting near-road concentrations and exposures for nearby populations. Air quality, wind tunnel and tracer gas measurement studies have identified the potential for noise barriers and roadside vegetation to reduce near-road air pollution concentrations, under some conditions by over 50 percent. However, some roadside conditions have been shown to result in increased downwind pollutant concentrations. The data from these studies have been used to develop and evaluate air dispersion model algorithms to simulate pollutant transport and dispersion around and over these features. This presentation will provide an overview of field and wind tunnel studies which have investigated how roadside features alter near-road air quality, how these studies have led to the development of dispersion model algorithms, and recommendations on the design and location of these features to maximize opportunities for pollution reduction and minimize potential increases in near-road pollutant concentrations. Presentation for the CRC MSAT workshop; requested by organizing committee and OTAQ

Plant growth regulators induced urease activity in Cucurbita pepo L. cotyledons.

PubMed

El Shora, Hamed M; Ali, Awatif S

2016-03-01

This study is aimed to investigate the activity of urease (EC 3.5.1.5, urea amidohydrolase) that catalyzes the hydrolysis of urea in 5-day-old Cucurbita pepo cotyledons subjected to various concentrations of different growth regulators. The treatment of C. pepo cotyledons with different concentrations (100-600 μmol) of different auxins [indole-3-acetic acid (IAA), indole butyric acid (IBA), indole propionic acid (IPA) and naphthalene acetic acid (NAA)]; or with different concentrations (100-300 μmol) of different cytokinins [kinetin, zeatin and benzyladenine (6-BA)] resulted in a significant increase of urease activity, compared to control. The optimal effects were recorded for each of 500 μmol of IAA and 300 μmol of zeatin treatments. A gradual increase in urease activity was detected in cotyledons treated with various concentrations (0.2-1.0 mM) of 28-homobrassinolide (HBL), in relative to control. A substantial increase in urease activity was observed in cotyledons subjected to different concentrations of triazole (10-60 mg L(-1)), containing either triadimefon (TDM) or hexaconazole (HEX), compared to control. The combination of 300 μmol zeatin with any of protein inhibitors, namely 5-fluorouridine (FUrd), cordycepin and α-amanitin, resulted in the alleviation of their inhibitory effect on the urease activity.

GABAergic miniature postsynaptic currents in septal neurons show differential allosteric sensitivity after binge-like ethanol exposure.

PubMed

DuBois, Dustin W; Trzeciakowski, Jerome P; Parrish, Alan R; Frye, Gerald D

2006-05-17

Binge-like ethanol treatment of septal neurons blunts GABAAR-mediated miniature postsynaptic currents (mPSCs), suggesting it arrests synaptic development. Ethanol may disrupt postsynaptic maturation by blunting feedback signaling through immature GABAARs. Here, the impact of ethanol on the sensitivity of mPSCs to zolpidem, zinc and 3alpha-hydroxy-5alpha-pregnan-20-one (3alpha-OH-DHP) was tested. The decay phase of mPSCs showed concentration-dependent potentiation by zolpidem (0.03-100 microM), which was substantially blunted after ethanol exposure. Since zolpidem potentiation exhibited a substantial age-dependent increase in untreated neurons, this finding supported the idea that ethanol arrests synaptic development. GABAAR alpha1 subunit protein also increased with age in untreated neurons, paralleling enhanced sensitivity to zolpidem. Surprisingly, alpha1 levels were not reduced by binge ethanol even though mPSCs were relatively zolpidem-insensitive. Zinc (3-30 microM) decreased mPSC parameters in a concentration- and age-related manner with older untreated cells showing less inhibition. However, there was no increase in mPSC zinc sensitivity after binge ethanol as would be expected if a general arrest of synaptic maturation had occurred. 3alpha-OH-DHP (3-1000 nM) induced concentration-dependent potentiation of mPSC decay. Although potentiation was age-independent, binge ethanol treatment exaggerated sensitivity to this neurosteroid. Finally, chronic picrotoxin pretreatment (100 microM) intended to mimic GABAAR inhibition from ethanol pretreatment did not significantly change mPSC modulation by zolpidem, zinc or 3alpha-OH-DHP. These results suggest that binge ethanol treatment selectively arrests a subset of processes important for maturation of postsynaptic GABAA Rs. However, it is unlikely that ethanol causes a broad arrest of postsynaptic development through a direct inhibition of GABAAR signaling.

The quality of our Nation's waters-Nutrients in the Nation's streams and groundwater, 1992-2004

USGS Publications Warehouse

Dubrovsky, N.M.; Burow, K.R.; Clark, G.M.; Gronberg, J.M.; Hamilton, P.A.; Hitt, K.J.; Mueller, D.K.; Munn, M.D.; Nolan, B.T.; Puckett, L.J.; Rupert, M.G.; Short, T.M.; Spahr, N.E.; Sprague, L.A.; Wilber, W.G.

2010-01-01

National Findings and Their Implications Although the use of artificial fertilizer has supported increasing food production to meet the needs of a growing population, increases in nutrient loadings from agricultural and, to a lesser extent, urban sources have resulted in nutrient concentrations in many streams and parts of aquifers that exceed standards for protection of human health and (or) aquatic life, often by large margins. Do NAWQA findings substantiate national concerns for aquatic and human health? National Water-Quality Assessment (NAWQA) findings indicate that nutrient concentrations in streams and groundwater in basins with significant agricultural or urban development are substantially greater than naturally occurring or ?background? levels. For example, median concentrations of total nitrogen and phosphorus in agricultural streams are about 6 times greater than background levels. Findings also indicate that concentrations in streams routinely were 2 to 10 times greater than regional nutrient criteria recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic life. Such large differences in magnitude suggest that significant reductions in sources of nutrients, as well as greater use of land management strategies to reduce the transport of nutrients to streams, are needed to meet recommended criteria for streams draining areas with significant agricultural and urban development. Nitrate concentrations above the Federal drinking-water standard-or Maximum Contaminant Level (MCL)-of 10 milligrams per liter (mg/L, as nit-ogen) are relatively uncommon in samples from streams used for drinking water or from relatively deep aquifers; the MCL is exceeded, however, in more than 20 percent of shallow (less than 100 feet below the water table) domestic wells in agricultural areas. This finding raises concerns for human health in rural agricultural areas where shallow groundwater is used for domestic supply and may warn of future contamination of deeper groundwater pumped from public-supply wells. Are levels of nutrients in water increasing or decreasing? A decadal assessment of trends in concentrations of nitrogen and phosphorus from about 1993 to 2003 shows minimal changes in those concentrations in the majority of studied streams across the Nation, and more upward than downward trends in concentrations at sites with changes. These findings underscore the need for reductions in nutrient inputs or management strategies that would reduce transport of nutrients to streams. Upward trends were evident among all land uses, including those only minimally affected by agricultural and (or) urban development, which suggests that additional protection of some of our Nation's most pristine streams warrants consideration. The median of nitrate concentrations in groundwater from 495 wells also increased significantly from 3.2 to 3.4 mg/L (6 percent) during about the same period, and the proportion of wells with concentrations of nitrate greater than the MCL increased from 16 to 21 percent. Nitrate concentrations in water in deep aquifers are likely to increase during the next decade as shallow groundwater with elevated concentrations moves downward. The potential for future contamination of the deep aquifers requires attention because these aquifers commonly are used for public water supply, and because restoration of groundwater is costly and difficult. Long-term and consistent monitoring of nutrients, improved accounting of nutrient sources, and improved tracking and modeling of climatic and landscape changes will be essential for distinguishing trends in nutrient concentrations, understanding the causes of those trends, and accurately tracking the effectiveness of strategies implemented to manage nutrients.

The quality of our Nation's waters-Nutrients in the Nation's streams and groundwater, 1992-2004

USGS Publications Warehouse

Dubrovsky, Neil M.; Burow, Karen R.; Clark, Gregory M.; Gronberg, JoAnn M.; Hamilton, Pixie A.; Hitt, Kerie J.; Mueller, David K.; Munn, Mark D.; Nolan, Bernard T.; Puckett, Larry J.; Rupert, Michael G.; Short, Terry M.; Spahr, Norman E.; Sprague, Lori A.; Wilber, William G.

2010-01-01

National Findings and Their ImplicationsAlthough the use of artificial fertilizer has supported increasing food production to meet the needs of a growing population, increases in nutrient loadings from agricultural and, to a lesser extent, urban sources have resulted in nutrient concentrations in many streams and parts of aquifers that exceed standards for protection of human health and (or) aquatic life, often by large margins.Do NAWQA findings substantiate national concerns for aquatic and human health?National Water-Quality Assessment (NAWQA) findings indicate that nutrient concentrations in streams and groundwater in basins with significant agricultural or urban development are substantially greater than naturally occurring or “background” levels. For example, median concentrations of total nitrogen and phosphorus in agricultural streams are about 6 times greater than background levels. Findings also indicate that concentrations in streams routinely were 2 to 10 times greater than regional nutrient criteria recommended by the U.S. Environmental Protection Agency (USEPA) to protect aquatic life. Such large differences in magnitude suggest that significant reductions in sources of nutrients, as well as greater use of land management strategies to reduce the transport of nutrients to streams, are needed to meet recommended criteria for streams draining areas with significant agricultural and urban development.Nitrate concentrations above the Federal drinking-water standard—or Maximum Contaminant Level (MCL)—of 10 milligrams per liter (mg/L, as nitrogen) are relatively uncommon in samples from streams used for drinking water or from relatively deep aquifers; the MCL is exceeded, however, in more than 20 percent of shallow (less than 100 feet below the water table) domestic wells in agricultural areas. This finding raises concerns for human health in rural agricultural areas where shallow groundwater is used for domestic supply and may warn of future contamination of deeper groundwater pumped from public‑supply wells.Are levels of nutrients in water increasing or decreasing?A decadal assessment of trends in concentrations of nitrogen and phosphorus from about 1993 to 2003 shows minimal changes in those concentrations in the majority of studied streams across the Nation, and more upward than downward trends in concentrations at sites with changes. These findings underscore the need for reductions in nutrient inputs or management strategies that would reduce transport of nutrients to streams. Upward trends were evident among all land uses, including those only minimally affected by agricultural and (or) urban development, which suggests that additional protection of some of our Nation’s most pristine streams warrants consideration.The median of nitrate concentrations in groundwater from 495 wells also increased significantly from 3.2 to 3.4 mg/L (6 percent) during about the same period, and the proportion of wells with concentrations of nitrate greater than the MCL increased from 16 to 21 percent. Nitrate concentrations in water in deep aquifers are likely to increase during the next decade as shallow groundwater with elevated concentrations moves downward. The potential for future contamination of the deep aquifers requires attention because these aquifers commonly are used for public water supply, and because restoration of groundwater is costly and difficult.Long-term and consistent monitoring of nutrients, improved accounting of nutrient sources, and improved tracking and modeling of climatic and landscape changes will be essential for distinguishing trends in nutrient concentrations, understanding the causes of those trends, and accurately tracking the effectiveness of strategies implemented to manage nutrients.

Process for producing a clean hydrocarbon fuel from high calcium coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kindig, J.K.

A method is described for substantially reducing the amount of at least one insoluble fluoride-forming species selected from the group consisting of Group IA species and Group IIA species. The species is present in a coal feed material comprising: forming a slurry of a coal feed; a fluoride acid in an amount to produce a first molar concentration of free-fluoride-ions; at least one fluoride-complexing species, the total of all fluoride-complexing species in the slurry being present in an amount to produce a second molar concentration, the second molar concentration being at least equal to that amount such that the ratiomore » of the first molar concentration to the second molar concentration is substantially equal to the stoichiometric ratio of fluoride in at least one tightly-bound complexion so as to from tightly-bound complexions with substantially all free-fluoride ions in the slurry to produce a leached coal product and a spent leach liquor; and separating the leached coal product from the spent leach liquor.« less

Effect of membrane filtration artifacts on dissolved trace element concentrations

USGS Publications Warehouse

Horowitz, Arthur J.; Elrick, Kent A.; Colberg, Mark R.

1992-01-01

Among environment scientists, the current and almost universally accepted definition of dissolved constituents is an operational one; only those materials which pass through a 0.45-??m membrane filter are considered to be dissolved. Detailed laboratory and field studies on Fe and Al indicate that a number of factors associated with filtration, other than just pore size, can substantially alter 'dissolved' trace element concentrations; these include: filter type, filter diameter, filtration method, volume of sample processed, suspended sediment concentration, suspended sediment grain-size distribution, concentration of colloids and colloidally associated trace elements and concentration of organic matter. As such, reported filtered-water concentrations employing the same pore size filter may not be equal. Filtration artifacts may lead to the production of chemical data that indicate seasonal or annual 'dissolved' chemical trends which do not reflect actual environmental conditions. Further, the development of worldwide averages for various dissolved chemical constituents, the quantification of geochemical cycles, and the determination of short- or long-term environmental chemical trends may be subject to substantial errors, due to filtration artifacts, when data from the same or multiple sources are combined. Finally, filtration effects could have a substantial impact on various regulatory requirements.

The effect of membrane filtration artifacts on dissolved trace element concentrations

USGS Publications Warehouse

Horowitz, A.J.; Elrick, K.A.; Colberg, M.R.

1992-01-01

Among environment scientists, the current and almost universally accepted definition of dissolved constituents is an operational one only those materials which pass through a 0.45-??m membrane filter are considered to be dissolved. Detailed laboratory and field studies on Fe and Al indicate that a number of factors associated with filtration, other than just pore size, can substantially alter 'dissolved' trace element concentrations; these include: filter type, filter diameter, filtration method, volume of sample processed, suspended sediment concentration, suspended sediment grain-size distribution, concentration of colloids and colloidally-associated trace elements and concentration of organic matter. As such, reported filtered-water concentrations employing the same pore size filter may not be equal. Filtration artifacts may lead to the production of chemical data that indicate seasonal or annual 'dissolved' chemical trends which do not reflect actual environmental conditions. Further, the development of worldwide averages for various dissolved chemical constituents, the quantification of geochemical cycles, and the determination of short- or long-term environmental chemical trends may be subject to substantial errors, due to filtration artifacts, when data from the same or multiple sources are combined. Finally, filtration effects could have a substantial impact on various regulatory requirements.

Annual and interannual variations of phytoplankton pigment concentration and upwelling along the Pacific equator

NASA Technical Reports Server (NTRS)

Halpern, David; Feldman, Gene C.

1994-01-01

The following variables along the Pacific equator from 145 deg E to 95 deg W were employed: surface layer phytoplankton pigment concentrations derived from Nimbus 7 coastal zone color scanner (CZCS) measurements of ocean color radiances; vertical velocities simulated at the 90-m bottom of the euphotic layer from a wind-driven ocean general circulation model; and nitrate concentrations estimated from model-simulated temperature. The upward flux of nitrate into the euphotic layer was calculated from the simulated vertical motion and nitrate concentration. The CZCS-derived phytoplankton pigment concentration was uniform from 175 deg to 95 deg W. Longitudinal profiles of upwelling, phytoplankton biomass, and 90-m nitrate flux were of different shapes. The small annual cycles of the phytoplankton pigment and nitrate flux were in phase: increased phytoplankton biomass was associated with increased upward nitrate flux, but the phase was not consistent with the annual cycles of the easterly wind or of the upwelling intensity. Variation of phytoplankton pigment concentration was greater during El Nino than during the annual cycle. The substantially reduced phytoplankton pigment concentration observed during El Nino was associated with smaller upward nitrate flux. Phytoplankton biomass during non-El Nino conditions was not related to nitrate flux into the euphotic layer.

Biochemical indicators of nephrotoxicity in blood serum of rats treated with novel 4-thiazolidinone derivatives or their complexes with polyethylene glycol-containing nanoscale polymeric carrier

PubMed

Kоbyli nska, L I; Havrylyuk, D Ya; Mitina, N E; Zaichenko, A S; Lesyk, R B; Zіme nkovsky, B S; Stoika, R S

2016-01-01

The aim of this study was to compare the effect of new synthetic 4-thiazolidinone derivatives (potential anticancer compounds denoted as 3882, 3288 and 3833) and doxorubicin (positive control) in free form and in their complexes with synthetic polyethylene glycol-containing nanoscale polymeric carrier on the biochemical indicators of nephrotoxicity in blood serum of rats. The concentration of total protein, urea, creatinine, glucose, ions of sodium, potassium, calcium, iron and chloride was measured. It was found that after injection of the investigated compounds, the concentration of sodium cations and chloride anions in blood serum was increased compared with control (untreated animals). Doxorubicin’s injection was accompanied by a decrease in the concentration of iron cations. The concentration of total protein, urea and creatinine decreased under the influence of the studied compounds. Complexation of these аntineoplastic substances with a synthetic polymeric nanocarrier lowered the concentration of the investigated metabolites substantially compared to the effect of these compounds in free form. The normalization of concentration of total protein, urea and creatinine in blood serum of rats treated with complexes of the studied compounds with the polymeric carrier comparing with increased concentration of these indicators at the introduction of such compounds in free form was found.

A solvent induced crystallisation method to imbue bioactive ingredients of neem oil into the compact structure of poly (ethylene terephthalate) polyester.

PubMed

Ali, Wazed; Sultana, Parveen; Joshi, Mangala; Rajendran, Subbiyan

2016-07-01

Neem oil, a natural antibacterial agent from neem tree (Azadarichtaindica) has been used to impart antibacterial activity to polyester fabrics. Solvent induced polymer modification method was used and that facilitated the easy entry of neem molecules into the compact structure of polyethylene terephthalate (PET) polyester. The polyester fabric was treated with trichloroacetic acid-methylene chloride (TCAMC) solvent system at room temperature prior to treatment with neem oil. The concentration of TCAMC and the treatment time were optimised. XRD and SEM results showed that the TCAMC treatment causes polymer modification and morphological changes in the PET polyester. Antibacterial activity of TCAMC pre-treated and neem-oil-treated polyester fabric was tested using AATCC qualitative and quantitative methods. Both Gram-positive and Gram-negative organisms were used to determine the antimicrobial activity. It was observed that the treated fabric registers substantial antimicrobial activity against both the Staphylococcus aureus (Gram-positive) and the Escherichia coli (Gram-negative) and the effect increases with the increase in concentration of TCAMC treatment. The antibacterial effect remains substantial even after 25 launderings. A kinetic growth study involving the effect of antibacterial activity at various incubation times was carried out. Copyright © 2016 Elsevier B.V. All rights reserved.

Strengthened African summer monsoon in the mid-Piacenzian

NASA Astrophysics Data System (ADS)

Zhang, Ran; Zhang, Zhongshi; Jiang, Dabang; Yan, Qing; Zhou, Xin; Cheng, Zhigang

2016-09-01

Using model results from the first phase of the Pliocene Model Intercomparison Project (PlioMIP) and four experiments with CAM4, the intensified African summer monsoon (ASM) in the mid-Piacenzian and corresponding mechanisms are analyzed. The results from PlioMIP show that the ASM intensified and summer precipitation increased in North Africa during the mid-Piacenzian, which can be explained by the increased net energy in the atmospheric column above North Africa. Further experiments with CAM4 indicated that the combined changes in the mid-Piacenzian of atmospheric CO2 concentration and SST, as well as the vegetation change, could have substantially increased the net energy in the atmospheric column over North Africa and further intensified the ASM. The experiments also demonstrated that topography change had a weak effect. Overall, the combined changes of atmospheric CO2 concentration and SST were the most important factor that brought about the intensified ASM in the mid-Piacenzian.

Sources, behaviors and degradation of dissolved organic matter in the East China Sea

NASA Astrophysics Data System (ADS)

Chen, Yan; Yang, Gui-Peng; Liu, Li; Zhang, Peng-Yan; Leng, Wei-Song

2016-03-01

Concentrations of dissolved organic carbon (DOC), dissolved inorganic nitrogen (DIN), dissolved organic nitrogen (DON) and its major compound classes-total hydrolysable amino acids (THAA) were measured at 4 cross-shelf transects of the East China Sea in July 2011. Surface concentrations of DOC, DIN, DON and THAA at the nearshore stations were mostly in excess of those found at the offshore sites, indicating either substantial autochthonous production or allochthonous inputs from the Changjiang River. The vertical distributions of DOC, DON and THAA showed similar trends with higher values in the surface layer, whereas the elevated concentrations of DIN were observed in the bottom layer. Major constituents of THAA presented in the study area were glycine, serine, alanine, glutamic acid, aspartic acid and valine. The mole percentages of neutral amino acids increased from surface water to bottom water, whereas acidic and hydroxy amino acids decreased with the water depth. Concentrations of DOC and THAA were negatively correlated to the ΔDIN values (the difference between the real concentration and theoretical concentration), respectively, indicating the coupling relation between dissolved organic matter (DOM) remineralization and nutrient regeneration in the water column. The C/N ratios in the water column exhibited different characteristics with elevated values appearing in the surface and bottom layers. Box and whisker plots showed that both degradation index (DI) values and THAA yields displayed a decreasing trend from the surface layer to the bottom layer, implying increasing degradation with the water depth. Our data revealed that glycine and alanine increased in relative abundance with decreasing DI, while tyrosine, valine, phenylalanine and isoleucine increased with increasing DI.

Sensitive liquid refractive index sensors using tapered optical fiber tips.

PubMed

Tai, Yi-Hsin; Wei, Pei-Kuen

2010-04-01

An optical fiber sensor based on the change of optical confinement in a subwavelength tip is presented. The optical spot is substantially increased when the environmental refractive index (RI) increases from 1.3 to 1.4. By measuring the intensity of low angular spectral components, an intensity sensitivity up to 8000% per RI unit is achieved. The fiber tip sensors take advantage of the small detection volume and real-time responses. We demonstrate the application of the nanofiber sensors for measuring concentrations of acids and evaporation rates of aqueous mixtures.

Modelling Escherichia coli concentrations in the tidal Scheldt river and estuary.

PubMed

de Brauwere, Anouk; de Brye, Benjamin; Servais, Pierre; Passerat, Julien; Deleersnijder, Eric

2011-04-01

Recent observations in the tidal Scheldt River and Estuary revealed a poor microbiological water quality and substantial variability of this quality which can hardly be assigned to a single factor. To assess the importance of tides, river discharge, point sources, upstream concentrations, mortality and settling a new model (SLIM-EC) was built. This model was first validated by comparison with the available field measurements of Escherichia coli (E. coli, a common fecal bacterial indicator) concentrations. The model simulations agreed well with the observations, and in particular were able to reproduce the observed long-term median concentrations and variability. Next, the model was used to perform sensitivity runs in which one process/forcing was removed at a time. These simulations revealed that the tide, upstream concentrations and the mortality process are the primary factors controlling the long-term median E. coli concentrations and the observed variability. The tide is crucial to explain the increased concentrations upstream of important inputs, as well as a generally increased variability. Remarkably, the wastewater treatment plants discharging in the study domain do not seem to have a significant impact. This is due to a dilution effect, and to the fact that the concentrations coming from upstream (where large cities are located) are high. Overall, the settling process as it is presently described in the model does not significantly affect the simulated E. coli concentrations. Copyright © 2011 Elsevier Ltd. All rights reserved.

Numerical simulation on the effects of drug eluting stents at different Reynolds numbers on hemodynamic and drug concentration distribution.

PubMed

Chen, Yu; Xiong, Yan; Jiang, Wentao; Yan, Fei; Guo, Meng; Wang, Qingyuan; Fan, Yubo

2015-01-01

The changes of hemodynamics and drug concentration distribution caused by the implantation of drug eluting stents (DESs) in curved vessels have significant effects on In-Stent Restenosis. A 3D virtual stent with 90° curvature was modelled and the distribution of wall shear stress (WSS) and drug concentration in this model were numerically studied at Reynolds numbers of 200, 400, 600, 800. The results showed that (1) the intensity of secondary flow at the 45° cross-section was stronger than that at the 90° cross-section; (2) As the Reynolds number increases, the WSS decreases. When the Reynolds number reaches 600, the low-WSS region only accounts for 3% of the total area. (3) The effects of Reynolds number on drug concentration in the vascular wall decreases in proportionally and then the blood velocity increased 4 times, the drug concentration in the vascular wall decreased by about 30%. (4) The size of the high drug concentration region is inversely proportional to the Reynolds number. As the blood velocity increases, the drug concentration in the DES decreases, especially at the outer bend. It is beneficial for the patient to decrease vigorous activities and keep calm at the beginning of the stent implantation, because a substantial amount of the drug is released in the first two months of stent implantation, thus a calm status is conducive to drug release and absorption; Subsequently, appropriate exercise which increases the blood velocity is helpful in decreasing regions of low-WSS.

Arsenic Attenuation By Oxidized Aquifer Sediments in Bangladesh

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stollenwerk, K.G.; Breit, G.N.; Welch, A.H.

2007-07-13

Recognition of arsenic (As) contamination of shallow fluvio-deltaic aquifers in the Bengal Basin has resulted in increasing exploitation of groundwater from deeper aquifers that generally contain low concentrations of dissolved As. Pumping-induced infiltration of high-As groundwater could eventually cause As concentrations in these aquifers to increase. This study investigates the adsorption capacity for As of sediment from a low-As aquifer near Dhaka, Bangladesh. A shallow, chemically-reducing aquifer at this site extends to a depth of 50 m and has maximum As concentrations in groundwater of 900 {micro}g/L. At depths greater than 50 m, geochemical conditions are more oxidizing and groundwatermore » has < 5 {micro}g/L As. There is no thick layer of clay at this site to inhibit vertical transport of groundwater. Arsenite [As(III)] is the dominant oxidation state in contaminated groundwater; however, data from laboratory batch experiments show that As(III) is oxidized to arsenate [As(V)] by manganese (Mn) minerals that are present in the oxidized sediment. Thus, the long-term viability of the deeper aquifers as a source of water supply is likely to depend on As(V) adsorption. The adsorption capacity of these sediments is a function of the oxidation state of As and the concentration of other solutes that compete for adsorption sites. Arsenite that was not oxidized did adsorb, but to a much lesser extent than As(V). Phosphate (P) caused a substantial decrease in As(V) adsorption. Increasing pH and concentrations of silica (Si) had lesser effects on As(V) adsorption. The effect of bicarbonate (HCO{sub 3}) on As(V) adsorption was negligible. Equilibrium constants for adsorption of As(V), As(III), P, Si, HCO3, and H were determined from the experimental data and a quantitative model developed. Oxidation of As(III) was modeled with a first-order rate constant. This model was used to successfully simulate As(V) adsorption in the presence of multiple competing solutes. Results from these experiments show that oxidized sediments have a substantial but limited capacity for removal of As from groundwater.« less

SU-F-T-663: Cerenkov Radiation Enhanced Radiotherapy with Titanium Dioxide Nanoparticle: A Monte Carlo Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, B; Sajo, E; Ouyang, Z

2016-06-15

Purpose: A recent publication has shown that by delivering titanium dioxide nanoparticles (titania) as a photosensitizer into tumors, Cerenkov radiation (CR) produced by radionuclides could be used for substantially boosting damage to cancer cells. The present work compares CR production by various clinically relevant radiation sources including internal radionuclides and external beam radiotherapy (EBRT), and provides preliminarily computational results of CR absorption by titania. Methods: 1) Geant4.10.1 was used to simulate ionizing radiation-induced CR production in a 1cm diameter spherical volume using external radiotherapy sources: Varian Clinac IX 6MV and Eldorado {sup 60}Co, both with 10*10 cm{sup 2} field size.more » In each case the volume was placed at the maximum dose depth (1.5cm for 6MV source and 0.5cm for {sup 60}Co). In addition, {sup 18}F, {sup 192}Ir and {sup 60}Co were simulated using Geant4 radioactive decay models as internal sources. Dose deposition and CR production spectra in 200nm-400nm range were calculated as it is the excitation range of titania. 2) Using 6MV external source, the absorption by titania was calculated via the track length of CR in the spherical volume. The nanoparticle concentration was varied from 0.25 to 5µg/g. Results: Among different radioactive sources, results showed that {sup 18}F induced the highest amount of CR per disintegration, but {sup 60}Co had the highest yield per unit dose. When compared with external sources, 6MV source was shown to be the most efficient for the the same delivered dose. Simulations indicated increased absorption for increasing concentrations, with up to 68% absorption of generated CR for 5µg/g titania concentration. Conclusion: The results demonstrate that 6MV beam is favored with a higher CR yield, compared to radionuclides, and that the use of higher concentrations of titania may increase photosensitization. From the findings, we propose that if sufficiently potent concentrations of titania are delivered to tumors this could substantially boost EBRT.« less

Arsenic attenuation by oxidized aquifer sediments in Bangladesh

USGS Publications Warehouse

Stollenwerk, K.G.; Breit, G.N.; Welch, A.H.; Yount, J.C.; Whitney, J.W.; Foster, A.L.; Uddin, M.N.; Majumder, R.K.; Ahmed, N.

2007-01-01

Recognition of arsenic (As) contamination of shallow fluvio-deltaic aquifers in the Bengal Basin has resulted in increasing exploitation of groundwater from deeper aquifers that generally contain low concentrations of dissolved As. Pumping-induced infiltration of high-As groundwater could eventually cause As concentrations in these aquifers to increase. This study investigates the adsorption capacity for As of sediment from a low-As aquifer near Dhaka, Bangladesh. A shallow, chemically-reducing aquifer at this site extends to a depth of 50??m and has maximum As concentrations in groundwater of 900????g/L. At depths greater than 50??m, geochemical conditions are more oxidizing and groundwater has < 5????g/L As. There is no thick layer of clay at this site to inhibit vertical transport of groundwater. Arsenite [As(III)] is the dominant oxidation state in contaminated groundwater; however, data from laboratory batch experiments show that As(III) is oxidized to arsenate [As(V)] by manganese (Mn) minerals that are present in the oxidized sediment. Thus, the long-term viability of the deeper aquifers as a source of water supply is likely to depend on As(V) adsorption. The adsorption capacity of these sediments is a function of the oxidation state of As and the concentration of other solutes that compete for adsorption sites. Arsenite that was not oxidized did adsorb, but to a much lesser extent than As(V). Phosphate (P) caused a substantial decrease in As(V) adsorption. Increasing pH and concentrations of silica (Si) had lesser effects on As(V) adsorption. The effect of bicarbonate (HCO3) on As(V) adsorption was negligible. Equilibrium constants for adsorption of As(V), As(III), P, Si, HCO3, and H were determined from the experimental data and a quantitative model developed. Oxidation of As(III) was modeled with a first-order rate constant. This model was used to successfully simulate As(V) adsorption in the presence of multiple competing solutes. Results from these experiments show that oxidized sediments have a substantial but limited capacity for removal of As from groundwater.

Regional assessment of persistent organic pollutants in resident mussels from New Jersey and New York estuaries following Hurricane Sandy

USGS Publications Warehouse

Smalling, Kelly L.; Deshpande, Ashok D.; Galbraith, Heather S.; Sharack, Beth; Timmons, DeMond; Baker, Ronald J.

2016-01-01

Resident mussels are effective indicators of ecosystem health and have been utilized in national assessment and monitoring studies for over two decades. Mussels were chosen because contaminant concentrations in their tissues respond to changes in ambient environmental levels, accumulation occurs with little metabolic transformation and a substantial amount of historic data were available. Mussels were collected from 10 previously studied locations approximately a year after Hurricane Sandy. Regionally, concentrations of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) decreased significantly, while concentrations of organochlorine pesticides (OCPs) remained unchanged, and polybrominated diphenyl ethers (PBDEs) increased compared to historic concentrations. Although concentrations of PCBs, OCPs and PAHs were at or near record low concentrations, long-term trends did not change after Hurricane Sandy. To effectively measure storm-induced impacts it is necessary to understand the factors influencing changes in mussel body burdens and have a long-term monitoring network and an ability to mobilize post event.

Regional assessment of persistent organic pollutants in resident mussels from New Jersey and New York estuaries following Hurricane Sandy.

PubMed

Smalling, Kelly L; Deshpande, Ashok D; Galbraith, Heather S; Sharack, Beth L; Timmons, DeMond; Baker, Ronald J

2016-06-30

Resident mussels are effective indicators of ecosystem health and have been utilized in national assessment and monitoring studies for over two decades. Mussels were chosen because contaminant concentrations in their tissues respond to changes in ambient environmental levels, accumulation occurs with little metabolic transformation and a substantial amount of historic data were available. Mussels were collected from 10 previously studied locations approximately a year after Hurricane Sandy. Regionally, concentrations of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) decreased significantly, while concentrations of organochlorine pesticides (OCPs) remained unchanged, and polybrominated diphenyl ethers (PBDEs) increased compared to historic concentrations. Although concentrations of PCBs, OCPs and PAHs were at or near record low concentrations, long-term trends did not change after Hurricane Sandy. To effectively measure storm-induced impacts it is necessary to understand the factors influencing changes in mussel body burdens and have a long-term monitoring network and an ability to mobilize post event. Published by Elsevier Ltd.

Estimation of the notch sensitivity of a nitrided steel by acoustic emission

NASA Astrophysics Data System (ADS)

Rogachev, S. O.; Nikulin, S. A.; Khatkevich, V. M.; Ozherelkov, D. Yu.; Molyarov, A. V.

2017-10-01

The notch sensitivity of sheet corrosion-resistant 08Kh17T steel is estimated in the states before and after high-temperature (1000-1100°C) internal nitriding during tensile tests accompanied by the measurement of acoustic emission signals. A crack in the steel is shown to propagate according to a ductile mechanism is all states. As the nitrogen content increases from 0.60 to 0.85%, the ultimate tensile strength of the steel decreases by 15% in the presence of a stress concentrator and remains substantially higher than the yield strength of the sheet steel without a stress concentrator.

Short-term ozone exposure and asthma severity: Weight-of-evidence analysis.

PubMed

Goodman, Julie E; Zu, Ke; Loftus, Christine T; Lynch, Heather N; Prueitt, Robyn L; Mohar, Isaac; Shubin, Sara Pacheco; Sax, Sonja N

2018-01-01

To determine whether evidence indicates that short-term exposure to ambient concentrations of ozone in the United States can affect asthma severity, we systematically reviewed published controlled human exposure, epidemiology, and animal toxicity studies. The strongest evidence for a potential causal relationship came from epidemiology studies reporting increased emergency department visits and hospital admissions for asthma following elevated ambient ozone concentrations. However, while controlled exposure studies reported lung function decrements and increased asthma symptoms following high ozone exposures 160-400 parts per billion [ppb]), epidemiology studies evaluating similar outcomes reported less consistent results. Animal studies showed changes in pulmonary function at high ozone concentrations (> 500ppb), although there is substantial uncertainty regarding the relevance of these animal models to human asthma. Taken together, the weight of evidence indicates that there is at least an equal likelihood that either explanation is true, i.e., the strength of the evidence for a causal relationship between short-term exposure to ambient ozone concentrations and asthma severity is "equipoise and above." Copyright © 2017 Elsevier Inc. All rights reserved.

Production factors influence fresh lamb longissimus colour more than muscle traits such as myoglobin concentration and pH.

PubMed

Calnan, H; Jacob, R H; Pethick, D W; Gardner, G E

2016-09-01

M. longissimus colour was measured from 8165 lambs at 24h post-mortem using a chromameter. The impact of production factors (site and year of production, slaughter group, sex, age and breed type) and muscle traits (hot carcass weight, pH24, isocitrate dehydrogenase (ICDH) activity, myoglobin, iron and zinc concentrations) on meat lightness (L*), redness (a*), yellowness (b*), hue and chroma were analysed. Greater differences in meat colour were seen between different slaughter groups and sites of production than across the range of any muscle traits. Of the muscle traits analysed, changes in pH24 had the greatest effect on meat a* (2.5 units), while myoglobin had the greatest effect on meat L* (2.9 units). The 3.1 L* unit darkening of meat with increasing lamb age (from 140 to 400days) was accounted for by increased myoglobin concentration. These results suggest that production factors are having substantial effects on lamb colour independent of known influencing muscle traits such as myoglobin concentration and pH. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of different types of soy sauce on the formation of heterocyclic amines in roasted chicken.

PubMed

Alam Shah, Syifaa; Selamat, Jinap; Haque Akanda, Md Jahurul; Sanny, Maimunah; Khatib, Alfi

2018-05-01

The objective of the study was to determine the effect of different types of soy sauce and marinating time on the formation of heterocyclic amines (HCAs) in roasted chicken. Chicken breast samples were marinated with sweet, salty, light and dark soy sauce at 0, 3, 6 and 12 h (control treatment was the chicken without marinade). The concentrations of free amino acids, sugars and creatinine were determined before roasting while HCA concentrations were determined after roasting. All types of soy sauce significantly increased (p ≤ 0.05) the concentration of HCAs in roasted chicken with increasing marinating time. The highest increment of total concentration of HCAs was found in samples marinated with light soy sauce (887%) followed by dark (375%), salty (193%) and sweet (169%) at 12 h. PhIP (2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine) showed a substantial reduction in samples only momentarily marinated with sweet, salty and dark soy sauce (0 h). Free amino acids were found to be more strongly correlated with the formation of HCAs than reducing sugars or creatinine.

An amphibian chemical defense phenotype is inducible across life history stages.

PubMed

Bucciarelli, Gary M; Shaffer, H Bradley; Green, David B; Kats, Lee B

2017-08-15

Inducible phenotypic responses to environmental variation are ubiquitous across the tree of life, but it remains an open question whether amphibian chemical defense phenotypes are inducible. Tetrodotoxin (TTX) is a key chemical defense trait in North American and Eurasian newts (Salamandridae). We tested if TTX can be induced by exposing populations of adult and larval California newts (Taricha torosa) to sustained stressful conditions while longitudinally quantifying TTX concentrations. Adult newts rapidly increased chemical defenses in response to simulated predator attacks and consistently maintained elevated TTX concentrations relative to wild, non-captive individuals. We also found that laboratory-reared larvae maintained chemical defenses nearly three-fold greater than those of siblings reared in streams. Collectively, our results indicate that amphibian chemical defenses are not fixed. Instead, toxins are maintained at a baseline concentration that can quickly be increased in response to perceived risk with substantial increases to toxicity. Therefore, it is crucial that inducible variation be accounted for when considering ecological dynamics of chemically defended animals and coevolutionary predator-prey and mimic-model relationships.

[Effect of exhaustive weightlifting exercise on EMG, biochemical markers of muscle damage and performance capacity in young male subjects].

PubMed

Minigalin, A D; Shumakov, A R; Novozhilov, A V; Samsonova, A V; Kos'mina, E A; Kalinskiĭ, M I; Baranova, T I; Kubasov, I V; Morozov, V I

2015-01-01

The aim of this study was to examine the effect of exhaustive weightlifting exercise on electrical and biochemical variables and performance capacity in young male subjects. The onset of exercise (80-50% 1RM) was associated with a decrease in the amount of work performed, which was followed by a steady performance capacity at 40-10% 1RM. There were no significant changes of m. rectus femoris EMG maximal amplitude though it tended to be increased during the first half of exercise. A significant blood lactate concentration increase indicated that an anaerobic metabolism was a predominant mechanism of muscle contraction energy-supply. CK level in blood plasma did not change but plasma myoglobin concentration doubled immediately post-exercise. The data presented here suggest that decrease in performance capacity was likely due to progressive "refusal of work" of the fast motor units and work prolongation of weaker, intermediate and slow motor units. Unchangeable CK activity and relatively small increase in myoglobin concentration in plasma suggest that used weightlifting exercise did not induced substantial damage in myocytes' membranes in our subjects.

Synergistic Effects of Nano-Sized Titanium Dioxide and Zinc on the Photosynthetic Capacity and Survival of Anabaena sp.

PubMed Central

Tang, Yulin; Li, Shuyan; Qiao, Junlian; Wang, Hongtao; Li, Lei

2013-01-01

Anabaena sp. was used to examine the toxicity of exposure to a nano-TiO2 suspension, Zn2+ solution, and mixtures of nano-TiO2 and Zn2+ suspensions. Typical chlorophyll fluorescence parameters, including effective quantum yield, photosynthetic efficiency and maximal electron transport rate, were measured by a pulse-amplitude modulated fluorometer. Nano-TiO2 particles exhibited no significant toxicity at concentrations lower than 10.0 mg/L. The 96 h concentration for the 50% maximal effect (EC50) of Zn2+ alone to Anabaena sp. was 0.38 ± 0.004 mg/L. The presence of nano-TiO2 at low concentrations (<1.0 mg/L) significantly enhanced the toxicity of Zn2+ and consequently reduced the EC50 value to 0.29 ± 0.003 mg/L. However, the toxicity of the Zn2+/TiO2 system decreased with increasing nano-TiO2 concentration because of the substantial adsorption of Zn2+ by nano-TiO2. The toxicity curve of the Zn2+/TiO2 system as a function of incremental nano-TiO2 concentrations was parabolic. The toxicity significantly increased at the initial stage, reached its maximum, and then decreased with increasing nano-TiO2 concentration. Hydrodynamic sizes, concentration of nano-TiO2 and Zn2+ loaded nano-TiO2 were the main parameters for synergistic toxicity. PMID:23852017

Biogeochemical patterns of intermittent streams over space and time as surface flows decrease

NASA Astrophysics Data System (ADS)

MacNeille, R. B.; Lohse, K. A.; Godsey, S.; McCorkle, E. P.; Parsons, S.; Baxter, C.

2016-12-01

Climate change in the western United States is projected to lead to earlier snowmelt, increasing fire risk and potentially transitioning perennial streams to intermittent ones. Differences between perennial and intermittent streams, especially the temporal and spatial patterns of carbon and nutrient dynamics during periods of drying, are understudied. We examined spatial and temporal patterns in surface water biogeochemistry in southwest Idaho and hypothesized that as streams dry, carbon concentrations would increase due to evapoconcentration and/or increased in-stream production. Furthermore, we expected that biogeochemical patterns of streams would become increasingly spatially heterogeneous with drying. Finally, we expected that these patterns would vary in response to fire. To test these hypotheses, we collected water samples every 50 meters from two intermittent streams, one burned and one unburned, in April, May and June, 2016 to determine surface water biogeochemistry. Results showed average concentrations of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) increased 3-fold from April to June in the burned site compared to the unburned site where concentrations remained relatively constant. Interestingly, average concentrations of total nitrogen (TN) dropped substantially for the burned site over these three months, but only decreased slightly for the unburned site over the same time period. We also assessed changes in spatial correlation between the burned and unburned site: carbon concentrations were less spatially correlated at the unburned site than at the burned site. Scatterplot matrices of DIC values indicated that at a lag distance of 300 m in April and June, the unburned site had r-values of 0.7416 and 0.5975, respectively, while the burned site had r-values of 0.9468 and 0.8783, respectively. These initial findings support our hypotheses that carbon concentrations and spatial heterogeneity increased over time.

Effect of elevated atmospheric CO2 concentration on growth and leaf litter decomposition of Quercus acutissima and Fraxinus rhynchophylla

PubMed Central

Cha, Sangsub; Chae, Hee-Myung; Lee, Sang-Hoon; Shim, Jae-Kuk

2017-01-01

The atmospheric carbon dioxide (CO2) level is expected to increase substantially, which may change the global climate and carbon dynamics in ecosystems. We examined the effects of an elevated atmospheric CO2 level on the growth of Quercus acutissima and Fraxinus rhynchophylla seedlings. We investigated changes in the chemical composition of leaf litter, as well as litter decomposition. Q. acutissima and F. rhynchophylla did not show differences in dry weight between ambient CO2 and enriched CO2 treatments, but they exhibited different patterns of carbon allocation, namely, lower shoot/root ratio (S/R) and decreased specific leaf area (SLA) under CO2-enriched conditions. The elevated CO2 concentration significantly reduced the nitrogen concentration in leaf litter while increasing lignin concentrations and carbon/nitrogen (C/N) and lignin/N ratios. The microbial biomass associated with decomposing Q. acutissima leaf litter was suppressed in CO2 enrichment chambers, while that of F. rhynchophylla was not. The leaf litter of Q. acutissima from the CO2-enriched chambers, in contrast with F. rhynchophylla, contained much lower nutrient concentrations than that of the litter in the ambient air chambers. Consequently, poorer litter quality suppressed decomposition. PMID:28182638

Effect of elevated atmospheric CO2 concentration on growth and leaf litter decomposition of Quercus acutissima and Fraxinus rhynchophylla.

PubMed

Cha, Sangsub; Chae, Hee-Myung; Lee, Sang-Hoon; Shim, Jae-Kuk

2017-01-01

The atmospheric carbon dioxide (CO2) level is expected to increase substantially, which may change the global climate and carbon dynamics in ecosystems. We examined the effects of an elevated atmospheric CO2 level on the growth of Quercus acutissima and Fraxinus rhynchophylla seedlings. We investigated changes in the chemical composition of leaf litter, as well as litter decomposition. Q. acutissima and F. rhynchophylla did not show differences in dry weight between ambient CO2 and enriched CO2 treatments, but they exhibited different patterns of carbon allocation, namely, lower shoot/root ratio (S/R) and decreased specific leaf area (SLA) under CO2-enriched conditions. The elevated CO2 concentration significantly reduced the nitrogen concentration in leaf litter while increasing lignin concentrations and carbon/nitrogen (C/N) and lignin/N ratios. The microbial biomass associated with decomposing Q. acutissima leaf litter was suppressed in CO2 enrichment chambers, while that of F. rhynchophylla was not. The leaf litter of Q. acutissima from the CO2-enriched chambers, in contrast with F. rhynchophylla, contained much lower nutrient concentrations than that of the litter in the ambient air chambers. Consequently, poorer litter quality suppressed decomposition.

An updated climatology of surface dimethlysulfide concentrations and emission fluxes in the global ocean

NASA Astrophysics Data System (ADS)

Lana, A.; Bell, T. G.; Simó, R.; Vallina, S. M.; Ballabrera-Poy, J.; Kettle, A. J.; Dachs, J.; Bopp, L.; Saltzman, E. S.; Stefels, J.; Johnson, J. E.; Liss, P. S.

2011-03-01

The potentially significant role of the biogenic trace gas dimethylsulfide (DMS) in determining the Earth's radiation budget makes it necessary to accurately reproduce seawater DMS distribution and quantify its global flux across the sea/air interface. Following a threefold increase of data (from 15,000 to over 47,000) in the global surface ocean DMS database over the last decade, new global monthly climatologies of surface ocean DMS concentration and sea-to-air emission flux are presented as updates of those constructed 10 years ago. Interpolation/extrapolation techniques were applied to project the discrete concentration data onto a first guess field based on Longhurst's biogeographic provinces. Further objective analysis allowed us to obtain the final monthly maps. The new climatology projects DMS concentrations typically in the range of 1-7 nM, with higher levels occurring in the high latitudes, and with a general trend toward increasing concentration in summer. The increased size and distribution of the observations in the DMS database have produced in the new climatology substantially lower DMS concentrations in the polar latitudes and generally higher DMS concentrations in regions that were severely undersampled 10 years ago, such as the southern Indian Ocean. Using the new DMS concentration climatology in conjunction with state-of-the-art parameterizations for the sea/air gas transfer velocity and climatological wind fields, we estimate that 28.1 (17.6-34.4) Tg of sulfur are transferred from the oceans into the atmosphere annually in the form of DMS. This represents a global emission increase of 17% with respect to the equivalent calculation using the previous climatology. This new DMS climatology represents a valuable tool for atmospheric chemistry, climate, and Earth System models.

Tropospheric ozone pollution in India: effects on crop yield and product quality.

PubMed

Singh, Aditya Abha; Agrawal, S B

2017-02-01

Ozone (O 3 ) in troposphere is the most critical secondary air pollutant, and being phytotoxic causes substantial losses to agricultural productivity. Its increasing concentration in India particularly in Indo-Gangetic plains is an issue of major concern as it is posing a threat to agriculture. In view of the issue of rising surface level of O 3 in India, the aim of this compilation is to present the past and the prevailing concentrations of O 3 and its important precursor (oxides of nitrogen) over the Indian region. The resulting magnitude of reductions in crop productivity as well as alteration in the quality of the product attributable to tropospheric O 3 has also been taken up. Studies in relation to yield measurements have been conducted predominantly in open top chambers (OTCs) and also assessed by using antiozonant ethylene diurea (EDU). There is a substantial spatial difference in O 3 distribution at different places displaying variable O 3 concentrations due to seasonal and geographical variations. This review further recognizes the major information lacuna and also highlights future perspectives to get the grips with rising trend of ground level O 3 pollution and also to formulate the policies to check the emissions of O 3 precursors in India.

Assessment of endocrine-disrupting chemicals attenuation in a coastal plain stream prior to wastewater treatment plant closure

USGS Publications Warehouse

Bradley, Paul M.; Journey, Celeste A.

2014-01-01

The U.S. Geological Survey is conducting a combined pre/post-closure assessment at a long-term wastewater treatment plant (WWTP) site at Fort Gordon near Augusta, Georgia. Here, we assess select endocrine-active chemicals and benthic macroinvertebrate community structure prior to closure of the WWTP. Substantial downstream transport and limited instream attenuation of endocrine-disrupting chemicals (EDCs) was observed in Spirit Creek over a 2.2-km stream segment downstream of the WWTP outfall. A modest decline (less than 20% in all cases) in surface water detections was observed with increasing distance downstream of the WWTP and attributed to partitioning to the sediment. Estrogens detected in surface water in this study included estrone (E1), 17β-estradiol (E2), and estriol (E3). The 5 ng/l and higher mean estrogen concentrations observed in downstream locations indicated that the potential for endocrine disruption was substantial. Concentrations of alkylphenol ethoxylate (APE) metabolite EDCs also remained statistically elevated above levels observed at the upstream control site. Wastewater-derived pharmaceutical and APE metabolites were detected in the outflow of Spirit Lake, indicating the potential for EDC transport to aquatic ecosystems downstream of Fort Gordon. The results indicate substantial EDC occurrence, downstream transport, and persistence under continuous supply conditions and provide a baseline for a rare evaluation of ecosystem response to WWTP closure.

Increased nuisance flooding along the coasts of the United States due to sea level rise: Past and future

NASA Astrophysics Data System (ADS)

Moftakhari, Hamed R.; AghaKouchak, Amir; Sanders, Brett F.; Feldman, David L.; Sweet, William; Matthew, Richard A.; Luke, Adam

2015-11-01

Mean sea level has risen tenfold in recent decades compared to the most recent millennia, posing a serious threat for population and assets in flood-prone coastal zones over the next century. An increase in the frequency of nuisance (minor) flooding has also been reported due to the reduced gap between high tidal datums and flood stage, and the rate of sea level rise (SLR) is expected to increase based on current trajectories of anthropogenic activities and greenhouse gases emissions. Nuisance flooding (NF), however nondestructive, causes public inconvenience, business interruption, and substantial economic losses due to impacts such as road closures and degradation of infrastructure. It also portends an increased risk in severe floods. Here we report substantial increases in NF along the coasts of United States due to SLR over the past decades. We then take projected near-term (2030) and midterm (2050) SLR under two representative concentration pathways (RCPs), 2.6 and 8.5, to estimate the increase in NF. The results suggest that on average, - 80 ± 10% local SLR causes the median of the NF distribution to increase by 55 ± 35% in 2050 under RCP8.5. The projected increase in NF will have significant socio-economic impacts and pose public health risks in coastal regions.

Synergistic Killing of Multidrug-Resistant Pseudomonas aeruginosa at Multiple Inocula by Colistin Combined with Doripenem in an In Vitro Pharmacokinetic/Pharmacodynamic Model ▿

PubMed Central

Bergen, Phillip J.; Tsuji, Brian T.; Bulitta, Jurgen B.; Forrest, Alan; Jacob, Jovan; Sidjabat, Hanna E.; Paterson, David L.; Nation, Roger L.; Li, Jian

2011-01-01

Combination therapy may be required for multidrug-resistant (MDR) Pseudomonas aeruginosa. The aim of this study was to systematically investigate bacterial killing and emergence of colistin resistance with colistin and doripenem combinations against MDR P. aeruginosa. Studies were conducted in a one-compartment in vitro pharmacokinetic/pharmacodynamic model for 96 h at two inocula (∼106 and ∼108 CFU/ml) against a colistin-heteroresistant reference strain (ATCC 27853) and a colistin-resistant MDR clinical isolate (19147 n/m). Four combinations utilizing clinically achievable concentrations were investigated. Microbiological response was examined by log changes and population analysis profiles. Colistin (constant concentrations of 0.5 or 2 mg/liter) plus doripenem (peaks of 2.5 or 25 mg/liter every 8 h; half-life, 1.5 h) substantially increased bacterial killing against both strains at the low inoculum, while combinations containing colistin at 2 mg/liter increased activity against ATCC 27853 at the high inoculum; only colistin at 0.5 mg/liter plus doripenem at 2.5 mg/liter failed to improve activity against 19147 n/m at the high inoculum. Combinations were additive or synergistic against ATCC 27853 in 16 and 11 of 20 cases (4 combinations across 5 sample points) at the 106- and 108-CFU/ml inocula, respectively; the corresponding values for 19147 n/m were 16 and 9. Combinations containing doripenem at 25 mg/liter resulted in eradication of 19147 n/m at the low inoculum and substantial reductions in regrowth (including to below the limit of detection at ∼50 h) at the high inoculum. Emergence of colistin-resistant subpopulations of ATCC 27853 was substantially reduced and delayed with combination therapy. This investigation provides important information for optimization of colistin-doripenem combinations. PMID:21911563

Influence of chemical disorder on energy dissipation and defect evolution in concentrated solid solution alloys

DOE PAGES

Zhang, Yanwen; Stocks, George Malcolm; Jin, Ke; ...

2015-10-28

A long-standing objective in materials research is to understand how energy is dissipated in both the electronic and atomic subsystems in irradiated materials, and how related non-equilibrium processes may affect defect dynamics and microstructure evolution. Here we show that alloy complexity in concentrated solid solution alloys having both an increasing number of principal elements and altered concentrations of specific elements can lead to substantial reduction in the electron mean free path and thermal conductivity, which has a significant impact on energy dissipation and consequentially on defect evolution during ion irradiation. Enhanced radiation resistance with increasing complexity from pure nickel tomore » binary and to more complex quaternary solid solutions is observed under ion irradiation up to an average damage level of 1 displacement per atom. Understanding how materials properties can be tailored by alloy complexity and their influence on defect dynamics may pave the way for new principles for the design of radiation tolerant structural alloys.« less

Metabolic influence of lead on polyhydroxyalkanoates (PHA) production and phosphate uptake in activated sludge fed with glucose or acetic acid as carbon source.

PubMed

You, Sheng-Jie; Tsai, Yung-Pin; Cho, Bo-Chuan; Chou, Yi-Hsiu

2011-09-01

Sludge in a sequential batch reactor (SBR) system was used to investigate the effect of lead toxicity on metabolisms of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) communities fed with acetic acid or glucose as their sole carbon source, respectively. Results showed that the effect of lead on substrate utilization of both PAOs and GAOs was insignificant. However, lead substantially inhibited both of phosphate release and uptake of PAOs. In high concentration of acetic acid trials, an abnormal aerobic phosphate release was observed instead of phosphate uptake and the release rate increased with increasing lead concentration. Results also showed that PAOs could normally synthesize polyhydroxybutyrate (PHB) in the anaerobic phase even though lead concentration was 40 mg L(-1). However, they could not aerobically utilize PHB normally in the presence of lead. On the other hand, GAOs could not normally metabolize polyhydroxyvalerate (PHV) in both the anaerobic and aerobic phases. Copyright © 2011 Elsevier Ltd. All rights reserved.

Increased CSF aquaporin-4, and interleukin-6 levels in dogs with idiopathic communicating internal hydrocephalus and a decrease after ventriculo-peritoneal shunting.

PubMed

Schmidt, Martin J; Rummel, Christoph; Hauer, Jessica; Kolecka, Malgorzata; Ondreka, Nele; McClure, Vanessa; Roth, Joachim

2016-06-29

Studies in animal models, in which internal hydrocephalus has been induced by obstructing the cerebrospinal fluid pathways, have documented an up-regulation of the concentrations of aquaporin-4 (AQP4) in the brain. In this study, the concentrations of aquaporin-1 (AQP1), AQP1, AQP4 and interleukin-6 (IL-6) were determined in the CSF of dogs with idiopathic communicating hydrocephalus before and after the reduction of intraventricular volume following ventriculo-peritoneal shunt (VP-shunt) treatment. The concentrations of AQP4 and IL-6 were increased in the cerebrospinal fluid of dogs with hydrocephalus compared to controls. Both parameters significantly decreased after surgical treatment, accompanied by decrease of ventricular size and the clinical recovery of the dogs. AQP1 was not detectable in CSF. Brain AQP4 up-regulation might be a compensatory response in dogs with hydrocephalus. Future determination of AQP4 at the mRNA and protein level in brain tissue is warranted to substantiate this hypothesis.

Mechanisms and implications of α-HCH enrichment in melt pond water on Arctic sea ice.

PubMed

Pućko, M; Stern, G A; Barber, D G; Macdonald, R W; Warner, K-A; Fuchs, C

2012-11-06

During the summer of 2009, we sampled 14 partially refrozen melt ponds and the top 1 m of old ice in the pond vicinity for α-hexachlorocyclohexane (α-HCH) concentrations and enantiomer fractions (EFs) in the Beaufort Sea. α-HCH concentrations were 3 - 9 times higher in melt ponds than in the old ice. We identify two routes of α-HCH enrichment in the ice over the summer. First, atmospheric gas deposition results in an increase of α-HCH concentration from 0.07 ± 0.02 ng/L (old ice) to 0.34 ± 0.08 ng/L, or ~20% less than the atmosphere-water equilibrium partitioning concentration (0.43 ng/L). Second, late-season ice permeability and/or complete ice thawing at the bottom of ponds permit α-HCH rich seawater (~0.88 ng/L) to replenish pond water, bringing concentrations up to 0.75 ± 0.06 ng/L. α-HCH pond enrichment may lead to substantial concentration patchiness in old ice floes, and changed exposures to biota as the surface meltwater eventually reaches the ocean through various drainage mechanisms. Melt pond concentrations of α-HCH were relatively high prior to the late 1980-s, with a Melt pond Enrichment Factor >1 (MEF; a ratio of concentration in surface meltwater to surface seawater), providing for the potential of increased biological exposures.

Ozone perturbations by enhanced levels of CFCs, N2O, and CH4 A two-dimensional diabatic circulation study including uncertainty estimates

NASA Technical Reports Server (NTRS)

Isaksen, I. S. A.; Stordal, F.

1986-01-01

Observations made over the last few years suggest that the tropospheric concentrations of N2O, CH4, and O3 are increasing. Increases in the concentration of chlorofluorocarbons (CFCs) have been observed for some time. The present study is concerned with combined scenarios of future releases of N2O, CH4, and CFCs, which can affect the height profiles of ozone, while changes in latitudinal gradients of ozone may also be expected. Ozone perturbation calculations performed in the two-dimensional transport-chemistry model described by Stordal et al. (1985) are also presented, and the effects of increased levels of CFCs, N2O, and CH4 are examined. It is found that CH4 may be the most important ozone-perturbing trace species in connection with future tropospheric climatic impacts. A substantial increase in the tropospheric abundancy of CH4 could lead to large future ozone enhancements throughout the troposphere and lower stratosphere at middle and low latitudes.

Water quality of the Little Arkansas River and Equus Beds Aquifer before and concurrent with large-scale artificial recharge, south-central Kansas, 1995-2012

USGS Publications Warehouse

Tappa, Daniel J.; Lanning-Rush, Jennifer L.; Klager, Brian J.; Hansen, Cristi V.; Ziegler, Andrew C.

2015-01-01

Recharge activities at Phase I recharge wells have not resulted in substantial effects on groundwater quality in the area, likely because the total amount of water recharged is relatively small (1 billion gallons) compared to aquifer storage volume (greater than 990 billion gallons in winter 2012). The eastward movement of the Burrton chloride plume is likely being slowed by a line of recharge locations associated with Phase I; however, chloride concentrations in deep groundwater still advanced to less than one half mile from the central part of the study area. Water-quality constituents of concern (major ions, nutrients, trace elements, triazine herbicides, and fecal indicator bacteria) have not increased substantially and are likely more affected by climatological (natural recharge by precipitation) and natural (geochemical oxidation/reduction, metabolic and decay rates) processes than artificial recharge. Arsenic remains a water-quality constituent of concern because of natural and continued persistence of concentrations exceeding the Federal maximum contaminant level of 10 micrograms per liter, especially in the deeper parts of theEquus Beds aquifer.

Photooxidation of dicarboxylic acids—Part I: Effects of inorganic ions on degradation of azelaic acid

NASA Astrophysics Data System (ADS)

Yang, Liming; Ray, Madhumita B.; Yu, Liya E.

In this paper, the first of a two-part series, effects of chloride, sulfate, and nitrate ions and pH on photooxidation of azelaic acid were investigated in an aqueous system. Nitrate ions play the major role in accelerating photooxidation of azelaic acid by increasing rad OH concentration, while chloride ions consume rad OH concentration and retard photooxidation rates. In inorganic mixtures, a nitrate-to-chloride molar ratio of >1.5 accelerated photooxidation of azelaic acid indicating the dominant role of nitrate. Substantial inhibition effects of chloride on photooxidation of azelaic acid were demonstrated at a nitrate-to-chloride molar ratio <0.3. Nitrate and chloride are interrelated in affecting photooxidation of azelaic acid as photolysis of nitrate would significantly consume H +, retarding reaction of HOCl - with H +, and consequently decreasing rad OH-chloride reaction. pH affects photooxidation of C 2-C 9 dicarboxylic acids (DCAs) in two ways: C 2-C 4 dicarboxylates exhibit substantially higher degradation rates than their parent DCAs, while C 5-C 9 dicarboxylates demonstrate degradation rates similar to their parent DCAs.

Evaluation of zinc oxide nanoparticles toxicity on marine algae chlorella vulgaris through flow cytometric, cytotoxicity and oxidative stress analysis.

PubMed

Suman, T Y; Radhika Rajasree, S R; Kirubagaran, R

2015-03-01

The increasing industrial use of nanomaterials during the last decades poses a potential threat to the environment and in particular to organisms living in the aquatic environment. In the present study, the toxicity of zinc oxide nanoparticles (ZnO NPs) was investigated in Marine algae Chlorella vulgaris (C. vulgaris). High zinc dissociation from ZnONPs, releasing ionic zinc in seawater, is a potential route for zinc assimilation and ZnONPs toxicity. To examine the mechanism of toxicity, C. vulgaris were treated with 50mg/L, 100mg/L, 200mg/L and 300 mg/L ZnO NPs for 24h and 72h. The detailed cytotoxicity assay showed a substantial reduction in the viability dependent on dose and exposure. Further, flow cytometry revealed the significant reduction in C. vulgaris viable cells to higher ZnO NPs. Significant reductions in LDH level were noted for ZnO NPs at 300 mg/L concentration. The activity of antioxidant enzyme superoxide dismutase (SOD) significantly increased in the C. vulgaris exposed to 200mg/L and 300 mg/L ZnO NPs. The content of non-enzymatic antioxidant glutathione (GSH) significantly decreased in the groups with a ZnO NPs concentration of higher than 100mg/L. The level of lipid peroxidation (LPO) was found to increase as the ZnO NPs dose increased. The FT-IR analyses suggested surface chemical interaction between nanoparticles and algal cells. The substantial morphological changes and cell wall damage were confirmed through microscopic analyses (FESEM and CM). Copyright © 2014 Elsevier Inc. All rights reserved.

Spectral reflectance as an indicator of foliar concentrations of arsenic in common sunflower (Helianthus annuus)

NASA Astrophysics Data System (ADS)

Gandy, Yuridia Patricia Peralta De

Studies were conducted to investigate the use of spectral reflectance by foliage of common sunflower as a potential indicator of arsenic contamination of soil. Germination method was developed for sunflower seeds, and cohorts of sunflower seedlings in hydroponic tanks were established. The cohorts were exposed to 0 ppm, 5 ppm, 7.5 ppm, and 10 ppm treatments of As (V) and reflectance measurements of foliage were collected using a spectroradiometer during two experiments. Results demonstrated the feasibility of using spectral reflectance by foliage of common sunflower as a potential indicator of arsenic contamination. In both experiments, arsenic concentrations in leaf tissues were directly proportional to arsenic concentrations in hydroponic solutions in which such plants were grown. Although the effect(s) of arsenic accumulation had minimal impact on reflectance of visible wavelengths, the effects on NIR reflectance were substantial and resulted in a progressive decrease in reflectance as arsenic concentrations in foliage increased.

Novel second-stage solar concentrator for parabolic troughs

NASA Astrophysics Data System (ADS)

Collares-Pereira, Manuel; Mendes, Joao F.

1995-08-01

Conventional parabolic troughs can be combined with second stage concentrators (SSC), to increase temperature and pressure inside the absorber, making possible the direct production of steam, improving substantially the overall system efficiency and leading to a new generation of distributed solar power plants. To attain this objective, research is needed at the optical, thermodynamic, system control, and engineering levels. In what concerns the receiver of such a system, different practical solutions have been proposed recently and in the past for the geometry of the second stage concentrator: CPC type and others. In this work we discuss these solutions and we propose a new one, 100% efficient in energy collection while reaching a total concentration ratio which is almost 65% of the thermodynamic limit. This SSC has an asymmetric elliptical geometry, rendering possible a smooth solution for the reflectors while maintaining a reasonable size for the receiver.

Production of Secondary Metabolites in Extreme Environments: Food- and Airborne Wallemia spp. Produce Toxic Metabolites at Hypersaline Conditions

PubMed Central

Frisvad, Jens C.; Kocev, Dragi; Džeroski, Sašo; Gunde-Cimerman, Nina

2016-01-01

The food- and airborne fungal genus Wallemia comprises seven xerophilic and halophilic species: W. sebi, W. mellicola, W. canadensis, W. tropicalis, W. muriae, W. hederae and W. ichthyophaga. All listed species are adapted to low water activity and can contaminate food preserved with high amounts of salt or sugar. In relation to food safety, the effect of high salt and sugar concentrations on the production of secondary metabolites by this toxigenic fungus was investigated. The secondary metabolite profiles of 30 strains of the listed species were examined using general growth media, known to support the production of secondary metabolites, supplemented with different concentrations of NaCl, glucose and MgCl2. In more than two hundred extracts approximately one hundred different compounds were detected using high-performance liquid chromatography-diode array detection (HPLC-DAD). Although the genome data analysis of W. mellicola (previously W. sebi sensu lato) and W. ichthyophaga revealed a low number of secondary metabolites clusters, a substantial number of secondary metabolites were detected at different conditions. Machine learning analysis of the obtained dataset showed that NaCl has higher influence on the production of secondary metabolites than other tested solutes. Mass spectrometric analysis of selected extracts revealed that NaCl in the medium affects the production of some compounds with substantial biological activities (wallimidione, walleminol, walleminone, UCA 1064-A and UCA 1064-B). In particular an increase in NaCl concentration from 5% to 15% in the growth media increased the production of the toxic metabolites wallimidione, walleminol and walleminone. PMID:28036382

Critical factors determining the variation in SOA yields from terpene ozonolysis: a combined experimental and computational study.

PubMed

Donahue, Neil M; Hartz, Kara E Huff; Chuong, Bao; Presto, Albert A; Stanier, Charles O; Rosenhørn, Thomas; Robinson, Allen L; Pandis, Spyros N

2005-01-01

A substantial fraction of the total ultrafine particulate mass is comprised of organic compounds. Of this fraction, a significant subfraction is secondary organic aerosol (SOA), meaning that the compounds are a by-product of chemistry in the atmosphere. However, our understanding of the kinetics and mechanisms leading to and following SOA formation is in its infancy. We lack a clear description of critical phenomena; we often don't know the key, rate limiting steps in SOA formation mechanisms. We know almost nothing about aerosol yields past the first generation of oxidation products. Most importantly, we know very little about the derivatives in these mechanisms; we do not understand how changing conditions, be they precursor levels, oxidant concentrations, co-reagent concentrations (i.e., the VOC/NOx ratio) or temperature will influence the yields of SOA. In this paper we explore the connections between fundamental details of physical chemistry and the multitude of steps associated with SOA formation, including the initial gas-phase reaction mechanisms leading to condensible products, the phase partitioning itself, and the continued oxidation of the condensed-phase organic products. We show that SOA yields in the alpha-pinene + ozone are highly sensitive to NOx, and that SOA yields from beta-caryophylene + ozone appear to increase with continued ozone exposure, even as aerosol hygroscopicity increases as well. We suggest that SOA yields are likely to increase substantially through several generations of oxidative processing of the semi-volatile products.

Pharmacokinetics of endoxifen and tamoxifen in female mice: implications for comparative in vivo activity studies.

PubMed

Reid, Joel M; Goetz, Matthew P; Buhrow, Sarah A; Walden, Chad; Safgren, Stephanie L; Kuffel, Mary J; Reinicke, Kathryn E; Suman, Vera; Haluska, Paul; Hou, Xiaonan; Ames, Matthew M

2014-12-01

Reduced CYP2D6 metabolism and low Z-endoxifen (ENDX) concentrations may increase the risk of breast cancer recurrence in tamoxifen (TAM)-treated women. Little is known regarding the differences between TAM and ENDX murine pharmacokinetics or the effect of administration route on plasma concentrations of each drug. The pharmacokinetics of TAM and ENDX were characterized in female mice. For subcutaneous [s.c.] and oral TAM (4, 10 and 20 mg/kg), TAM AUC increased in a linear manner, but concentrations of the active metabolites [ENDX and 4-hydroxytamoxifen (4HT)] remained low. For oral TAM (20 mg), 4HT concentrations were tenfold greater (>25 ng/ml) than achievable in TAM-treated humans. Both oral (10-200 mg/kg) and s.c. (2.5-25 mg/kg) ENDX·HCl resulted in a greater than dose-proportional increase in AUC, with eightfold greater ENDX concentrations than an equivalent TAM dose. ENDX accumulated in plasma after 5-day dosing of 25 or 100 mg/kg ENDX·HCl and exceeded target concentrations of 0.1 and 1.0 μM, respectively, by twofold to fourfold. In murine models, oral ENDX yields substantially higher ENDX concentrations, compared to TAM. The low 4HT and ENDX concentrations observed in mice receiving s.c. TAM mirror the TAM pharmacokinetics in humans with impaired CYP2D6 metabolism. These data support the ongoing development of ENDX as a novel agent for the endocrine treatment of ER-positive breast cancer.

Ultrasonication as a potential tool to predict solute crystallization in freeze-concentrates.

PubMed

Ragoonanan, Vishard; Suryanarayanan, Raj

2014-06-01

We hypothesize that ultrasonication can accelerate solute crystallization in freeze-concentrates. Our objective is to demonstrate ultrasonication as a potential predictive tool for evaluating physical stability of excipients in frozen solutions. The crystallization tendencies of lyoprotectants (trehalose, sucrose), carboxylic acid buffers (citric, tartaric, malic, and acetic) and an amino acid buffer (histidine HCl) were studied. Aqueous solutions of buffers, lyoprotectants and mixtures of the two were cooled from room temperature to -20°C and sonicated to induce solute crystallization. The crystallized phases were identified by X-ray diffractometry (laboratory or synchrotron source). Sonication accelerated crystallization of trehalose dihydrate in frozen trehalose solutions. Sonication also enhanced solute crystallization in tartaric (200 mM; pH 5), citric (200 mM pH 4) and malic (200 mM; pH 4) acid buffers. At lower buffer concentrations, longer annealing times following sonication were required to facilitate solute crystallization. The time for crystallization of histidine HCl progressively increased as a function of sucrose concentration. The insonation period required to effect crystallization also increased with sucrose concentration. Sonication can substantially accelerate solute crystallization in the freeze-concentrate. Ultrasonication may be useful in assessing the crystallization tendency of formulation constituents used in long term frozen storage and freeze-drying.

Spatial and temporal variations of the concentrations of PM10, PM2.5 and PM1 in China

NASA Astrophysics Data System (ADS)

Wang, Y. Q.; Zhang, X. Y.; Sun, J. Y.; Zhang, X. C.; Che, H. Z.; Li, Y.

2015-06-01

Concentrations of PM10, PM2.5 and PM1 were monitored at 24 stations of CAWNET (China Atmosphere Watch Network) from 2006 to 2014 using GRIMM 180 dust monitors. The highest particulate matter (PM) concentrations were observed at the stations of Xian, Zhengzhou and Gucheng, in Guanzhong and the Hua Bei Plain (HBP). The second highest PM concentrations were observed in northeast China, followed by southern China. According to the latest air quality standards of China, 14 stations reached the PM10 standard and only 7 stations, mainly rural and remote stations, reached the PM2.5 standard. The PM2.5 and PM10 ratios showed a clear increasing trend from northern to southern China, because of the substantial contribution of coarse mineral aerosol in northern China. The PM1 and PM2.5 ratios were higher than 80% at most stations. PM concentrations tended to be highest in winter and lowest in summer at most stations, and mineral dust impacts influenced the results in spring. A decreasing interannual trend was observed in the HBP and southern China from 2006 to 2014, but an increasing trend occurred at some stations in northeast China. Also diurnal variations of PM concentrations and meteorological factors effects were investigated.

Low-density lipoprotein transport in blood vessel walls of squirrel monkeys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tompkins, R.G.; Yarmush, M.L.; Schnitzer, J.J.

1989-08-01

Transmural accumulations of low-density lipoprotein (LDL) were examined in the blood vessel walls of four squirrel monkeys. Vascular wall concentrations of LDL were measured using quantitative autoradiography after {sup 125}I-labeled LDL circulation for 30 min. Profiles of relative tissue concentration from different sections in the same region were similar to each other, and there was little animal-to-animal variation. Concentrations were highest near the luminal endothelium, lower near the medial-adventitial border, and lowest within the media. Profiles from different regions fell into three groups: (1) aortic samples had steep intimal concentration gradients and near-zero media concentrations; (2) the iliac, femoral, popliteal,more » and common carotid arteries had higher intimal concentrations than group 1 but had similar concentrations deep within the media; and (3) the cerebral and coronary arteries, inferior vena cava, and pulmonary artery had intimal concentrations that were similar to group 2, but the concentrations deep within the media were greater than either groups 1 or 2. Arterial bifurcation profiles from the inner wall and the outer walls were similar to each other and to profiles from the upstream and downstream areas. Out of 280 total sites examined, 15 examples of profiles with substantially increased concentrations near the luminal endothelium were found scattered throughout the cardiovascular system, demonstrating that there are focal regions throughout the cardiovascular system which have greatly increased {sup 125}I-LDL transendothelial permeability.« less

Effectiveness of dishwashing liquids in removing chlorothalonil and chlorpyrifos residues from cherry tomatoes.

PubMed

Wang, Zhiwei; Huang, Jiexun; Chen, Jinyuan; Li, Feili

2013-08-01

Washing is the most practical way to remove pesticide residues in fruits and vegetables. Two commonly used kitchen dishwashing liquids (detergents) in Chinese market were tested for enhanced removal of chlorpyrifos (CHP) and chlorothalonil (CHT) in cherry tomatoes by soaking the cherry tomatoes in the detergent solutions. The critical micelle concentrations of detergent A and detergent B were about 250 mg L(-1) and 444 mg L(-1), respectively. Detergent A had a higher solubilizing ability for pesticides and hence washing effectiveness than detergent B. The apparent solubility of CHP increased with increasing detergent concentration, while that of CHT remained comparatively invariant independent of detergent concentration within the tested range. The apparent solubility of CHP was also consistently higher in solutions of both detergents as compared to CHT. Due probably to its lower logKow value, CHT was more readily washed off cherry tomatoes than CHP. In terms of washing, a duration of 10-20 min was sufficient for removal of pesticides on cherry tomatoes in distilled water and detergent solutions. The effectiveness of removing pesticides increased with increasing detergent concentration from 50 mg L(-1) to 5 g L(-1), with up to 80% CHT and 42% CHP removed. Multiple washing further increased pesticide removal. Adding 10% acetic acid to lower pH or increasing washing temperature favored pesticide removal, but 10% NaCl produced the shielding effect and substantially reduced the effectiveness of detergent A for pesticide removal. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of experimental CO2 leakage on solubility and transport of seven trace metals in seawater and sediment.

PubMed

Ardelan, Murat V; Steinnes, Eiliv; Lierhagen, Syverin; Linde, Sven Ove

2009-12-01

The impact of CO(2) leakage on solubility and distribution of trace metals in seawater and sediment has been studied in lab scale chambers. Seven metals (Al, Cr, Ni, Pb, Cd, Cu, and Zn) were investigated in membrane-filtered seawater samples, and DGT samplers were deployed in water and sediment during the experiment. During the first phase (16 days), "dissolved" (<0.2 microm) concentrations of all elements increased substantially in the water. The increase in dissolved fractions of Al, Cr, Ni, Cu, Zn, Cd and Pb in the CO(2) seepage chamber was respectively 5.1, 3.8, 4.5, 3.2, 1.4, 2.3 and 1.3 times higher than the dissolved concentrations of these metals in the control. During the second phase of the experiment (10 days) with the same sediment but replenished seawater, the dissolved fractions of Al, Cr, Cd, and Zn were partly removed from the water column in the CO(2) chamber. DNi and DCu still increased but at reduced rates, while DPb increased faster than that was observed during the first phase. DGT-labile fractions (Me(DGT)) of all metals increased substantially during the first phase of CO(2) seepage. DGT-labile fractions of Al, Cr, Ni, Cu, Zn, Cd and Pb were respectively 7.9, 2.0, 3.6, 1.7, 2.1, 1.9 and 2.3 times higher in the CO(2) chamber than that of in the control chamber. Al(DGT), Cr(DGT), Ni(DGT), and Pb(DGT) continued to increase during the second phase of the experiment. There was no change in Cd(DGT) during the second phase, while Cu(DGT) and Zn(DGT) decreased by 30% and 25%, respectively in the CO(2) chamber. In the sediment pore water, DGT labile fractions of all the seven elements increased substantially in the CO(2) chamber. Our results show that CO(2) leakage affected the solubility, particle reactivity and transformation rates of the studied metals in sediment and at the sediment-water interface. The metal species released due to CO(2) acidification may have sufficiently long residence time in the seawater to affect bioavailability and toxicity of the metals to biota.

Exposure Potential and Health Impacts of Indium and Gallium, Metals Critical to Emerging Electronics and Energy Technologies.

PubMed

White, Sarah Jane O; Shine, James P

2016-12-01

The rapid growth of new electronics and energy technologies requires the use of rare elements of the periodic table. For many of these elements, little is known about their environmental behavior or human health impacts. This is true for indium and gallium, two technology critical elements. Increased environmental concentrations of both indium and gallium create the potential for increased environmental exposure, though little is known about the extent of this exposure. Evidence is mounting that indium and gallium can have substantial toxicity, including in occupational settings where indium lung disease has been recognized as a potentially fatal disease caused by the inhalation of indium particles. This paper aims to review the basic chemistry, changing environmental concentrations, potential for human exposure, and known health effects of indium and gallium.

Total mercury concentration in sediment from the continental shelf of central California

NASA Astrophysics Data System (ADS)

Acosta, R. M.; Weiss-Penzias, P. S.; Bauer, V.; Ryan, J. P.; Flegal, A. R.

2012-12-01

In order to understand the biogeochemical distribution of mercury (Hg) and locate specific Hg hot spots in the coastal region of central California, total mercury (HgT) concentration were measured in 43 archived sediment cores collected between Año Nuevo and the southern end of Monterey Bay. The samples were taken from USGS in Menlo Park, California on May 4th 2012. The cores were collected through the Environmental Management Assessment Program (EMAP), with ID sites: M-1-95-MB, P-2-95-MB and P-1-97-MB. For the purpose of this study we assumed that there has been negligible diagenesis on trace metal Hg since samples were taken. Total Hg concentrations were measured on the top five cm of the cores and yielded a mean of 0.037 μg g-1, and ranged from 0.013 to 0.113 μg g-1. In addition, the 43 samples were split into nine transects, and transects found near the mouth of Monterey Bay submarine canyon (MBSC) contained the highest concentration of HgT, with a mean concentration of 0.043 μg g-1, and ranged from 0.038 to 0.113 μg g-1. This substantial increase in HgT concentration near MBSC might be a product of the bathymetry acting as a sink or interaction between internal waves and the canyon's rim. This allows reactivation of surface sediment, which can separate fine grained sand, mud and clay content near the mid-shelf region and the canyon rim. Three depth profiles with 0-30 cm intervals were measured for HgT concentrations. Cores averaged mean HgT concentrations of 0.032, 0.040, and 0.037 μg g-1, while each profile ranged from 0.025-0.043, 0.028-0.065 and 0.022-0.051 μg g-1. Each depth profile had slight variations in HgT concentrations. One core located between Daven Port and Santa Cruz displayed decreasing HgT concentration with increasing depth. The inconsistency seen in the depth profiles might be products of external factors such as textural changes as depth increases, changes in Hg fluxes, bio mixing, and diagenesis such as redox reactions. Furthermore, comparisons of our data with sedimentation rates found in Monterey Bay have shown mercury concentration in the sediment not influenced by sedimentation rates. Instead, we observed decrease in mud content corresponded to decrease in HgT concentrations; perhaps supporting Hg's strong correlation to organic matter. Although, the sediment Hg concentration in the coastal regions of Monterey Bay, was substantially lower than those found in San Francisco Bay, the data found in this study is conclusive that the hot spots found near MBSC could be an overlooked source of Hg in coastal environments and needs further investigation.

Sea-level Rise Increases the Frequency of Nuisance Flooding in Coastal Regions

NASA Astrophysics Data System (ADS)

Moftakhari Rostamkhani, H.; Aghakouchak, A.; Sanders, B. F.; Feldman, D.; Sweet, W.; Matthew, R.; Luke, A.

2015-12-01

The global warming-drivensea-level rise (SLR) posesa serious threat for population and assets in flood-prone coastal zones over the next century. The rate of SLR is accelerated in recent decades and is expected to increase based on current trajectories of anthropogenic activities and greenhouse gas emissions. Over the 20th century, an increase in the frequency of nuisance (minor) flooding has been reported due to the reduced gap between tidal datum and flood stage. Nuisance flooding (NF), however non-destructive, causes public inconvenience, business interruption, and substantial economic losses due to impacts such as road closures and degradation of infrastructure. It also portends an increased risk in severe floods. Here we report substantial increases in NF along the coasts of United States due to SLR over the past decades. We then take the projected SLR under the least and the most extreme representative concentration pathways (e.gRCP2.6 and RCP 8.5) to estimate the increase in NF in the near- (2030) and mid-term (2050) future. The results suggest that projected SLR will cause up to two-fold more frequent NF by 2050, compared with the 20th century. The projected increase in NF will have significant socio-economic impacts and pose public health risks especially in rapidly urbanized coastal regions.

Road dust emissions from paved roads measured using different mobile systems.

PubMed

Pirjola, Liisa; Johansson, Christer; Kupiainen, Kaarle; Stojiljkovic, Ana; Karlsson, Hans; Hussein, Tareq

2010-12-01

Very few real-world measurements of road dust suspension have been performed to date. This study compares two different techniques (referred to as Sniffer and Emma) to measure road dust emissions. The main differences between the systems are the construction of the inlet, different instruments for recording particulate matter (PM) levels, and different loads on the wheel axes (the weight of Sniffer was much higher than that of Emma). Both systems showed substantial small-scale variations of emission levels along the road, likely depending on-road surface conditions. The variations observed correlated quite well, and the discrepancies are likely a result of variations in dust load on the road surface perpendicular to the driving direction that cause variations in the measurements depending on slightly different paths driven by the two vehicles. Both systems showed a substantial influence on the emission levels depending on the type of tire used. The summer tire showed much lower suspension than the winter tires (one nonstudded and one studded). However, the relative importance of the nonstudded versus studded tire was rather different. For the ratio of studded/nonstudded, Emma shows higher values on all road sections compared with Sniffer. Both techniques showed increased emission levels with increasing vehicle speed. When the speed increased from 50 to 80 km hr(-1), the relative concentrations increased by 30-170% depending on the tire type and dust load. However, for road sections that were very dirty, Sniffer showed a much higher relative increase in the emission level with the nonstudded tire. Sniffer's absolute concentrations were mostly higher than Emma's. Possible reasons for the differences are discussed in the paper. Both systems can be used for studying relative road dust emissions and for designing air quality management strategies.

Cannabis Effects on Driving Skills

PubMed Central

Hartman, Rebecca L.; Huestis, Marilyn A.

2013-01-01

BACKGROUND Cannabis is the most prevalent illicit drug identified in impaired drivers. The effects of cannabis on driving continue to be debated, making prosecution and legislation difficult. Historically, delays in sample collection, evaluating the inactive Δ9-tetrahydrocannabinol (THC) metabolite 11-nor-9-carboxy-THC, and polydrug use have complicated epidemiologic evaluations of driver impairment after cannabis use. CONTENT We review and evaluate the current literature on cannabis’ effects on driving, highlighting the epidemiologic and experimental data. Epidemiologic data show that the risk of involvement in a motor vehicle accident (MVA) increases approximately 2-fold after cannabis smoking. The adjusted risk of driver culpability also increases substantially, particularly with increased blood THC concentrations. Studies that have used urine as the biological matrix have not shown an association between cannabis and crash risk. Experimental data show that drivers attempt to compensate by driving more slowly after smoking cannabis, but control deteriorates with increasing task complexity. Cannabis smoking increases lane weaving and impaired cognitive function. Critical-tracking tests, reaction times, divided-attention tasks, and lane-position variability all show cannabis-induced impairment. Despite purported tolerance in frequent smokers, complex tasks still show impairment. Combining cannabis with alcohol enhances impairment, especially lane weaving. SUMMARY Differences in study designs frequently account for inconsistencies in results between studies. Participant-selection bias and confounding factors attenuate ostensible cannabis effects, but the association with MVA often retains significance. Evidence suggests recent smoking and/or blood THC concentrations 2–5 ng/mL are associated with substantial driving impairment, particularly in occasional smokers. Future cannabis-and-driving research should emphasize challenging tasks, such as divided attention, and include occasional and chronic daily cannabis smokers. PMID:23220273

DBP formation in hot and cold water across a simulated distribution system: effect of incubation time, heating time, pH, chlorine dose, and incubation temperature.

PubMed

Liu, Boning; Reckhow, David A

2013-10-15

This paper demonstrates that disinfection byproducts (DBP) concentration profiles in heated water were quite different from the DBP concentrations in the cold tap water. Chloroform concentrations in the heated water remained constant or even decreased slightly with increasing distribution system water age. The amount of dichloroacetic acid (DCAA) was much higher in the heated water than in the cold water; however, the maximum levels in heated water with different distribution system water ages did not differ substantially. The levels of trichloroacetic acid (TCAA) in the heated water were similar to the TCAA levels in the tap water, and a slight reduction was observed after the tap water was heated for 24 h. Regardless of water age, significant reductions of nonregulated DBPs were observed after the tap water was heated for 24 h. For tap water with lower water ages, there were significant increases in dichloroacetonitrile (DCAN), chloropicrin (CP), and 1,1-dichloropropane (1,1-DCP) after a short period of heating. Heating of the tap water with low pH led to a more significant increase of chloroform and a more significant short-term increase of DCAN. High pH accelerated the loss of the nonregulated DBPs in the heated water. The results indicated that as the chlorine doses increased, levels of chloroform and DCAA in the heated water increased significantly. However, for TCAA, the thermally induced increase in concentration was only notable for the chlorinated water with very high chlorine dose. Finally, heating may lead to higher DBP concentrations in chlorinated water with lower distribution system temperatures.

Impacts of fire on nitrogen cycling in aquatic and terrestrial ecosystems in the Yukon-Kuskokwim River Delta, AK

NASA Astrophysics Data System (ADS)

Schade, J. D.; Jardine, L. E.; Bristol, E. M.; Navarro-Perez, E.; Melton, S.; Jimmie, J. A.; Natali, S.; Mann, P. J.; Holmes, R. M.

2016-12-01

Global climate change is having a disproportionate impact on northern high latitudes, including rapid increases in temperature, changes in precipitation, and increasing fire frequency and severity. Wildfires have been shown to strongly influence ecosystem processes through acceleration of permafrost thaw and increased nitrogen (N) availability, the effects of which may increase gaseous loss of carbon (C) to the atmosphere, increase primary production by alleviating N limitation, or both. The extent of these fire impacts has not been well-documented in the Arctic, particularly in areas of discontinuous permafrost. In 2015, the Yukon-Kuskokwim River Delta (YK Delta) in southwestern Alaska experienced the largest fire season in recorded history, providing an opportunity to study wildfire impacts on an area particularly vulnerable to permafrost thaw. Our objectives were to study the impacts of these fires on nitrogen availability in a range of land cover classes, including peat plateaus, channel fens, and aquatic ecosystems distributed across the landscapes. We sampled soils from several vegetation patches on burned and unburned peat plateaus, and soil and surface waters from fens, small ponds, and streams downslope of these sites. All water samples were filtered through GFF filters in the field. Soils were transported frozen to the Woods Hole Research Center and extracted in KCl. All water samples and extracts were analyzed for NH4 and NO3 concentrations. We found substantially higher concentrations of extractable NH4 in burned soils, but very little extractable NO3 in either burned or unburned soils. Water samples also showed higher NH4 in aquatic ecosystems in burned watersheds, but, in contrast to soils, showed relatively high NO3 concentrations, particularly in waters from lower landscape positions. Overall, aquatic ecosystems exhibited higher NO3: NH4 ratios than soil extractions, and increasing NO3: NH4 downslope. These results suggest significant export of nitrogen after fire and the potential for nitrification as N is transported across the landscape. These changes in N cycling are likely to have substantial consequences for the recovery of plant communities post-fire and for microbial processes and greenhouse gas fluxes, including N2O, from burned watersheds.

Impacts of fire on nitrogen cycling in aquatic and terrestrial ecosystems in the Yukon-Kuskokwim River Delta, AK

NASA Astrophysics Data System (ADS)

Schade, J. D.; Jardine, L. E.; Bristol, E. M.; Navarro-Perez, E.; Melton, S.; Jimmie, J. A.; Natali, S.; Mann, P. J.; Holmes, R. M.

2017-12-01

Global climate change is having a disproportionate impact on northern high latitudes, including rapid increases in temperature, changes in precipitation, and increasing fire frequency and severity. Wildfires have been shown to strongly influence ecosystem processes through acceleration of permafrost thaw and increased nitrogen (N) availability, the effects of which may increase gaseous loss of carbon (C) to the atmosphere, increase primary production by alleviating N limitation, or both. The extent of these fire impacts has not been well-documented in the Arctic, particularly in areas of discontinuous permafrost. In 2015, the Yukon-Kuskokwim River Delta (YK Delta) in southwestern Alaska experienced the largest fire season in recorded history, providing an opportunity to study wildfire impacts on an area particularly vulnerable to permafrost thaw. Our objectives were to study the impacts of these fires on nitrogen availability in a range of land cover classes, including peat plateaus, channel fens, and aquatic ecosystems distributed across the landscapes. We sampled soils from several vegetation patches on burned and unburned peat plateaus, and soil and surface waters from fens, small ponds, and streams downslope of these sites. All water samples were filtered through GFF filters in the field. Soils were transported frozen to the Woods Hole Research Center and extracted in KCl. All water samples and extracts were analyzed for NH4 and NO3 concentrations. We found substantially higher concentrations of extractable NH4 in burned soils, but very little extractable NO3 in either burned or unburned soils. Water samples also showed higher NH4 in aquatic ecosystems in burned watersheds, but, in contrast to soils, showed relatively high NO3 concentrations, particularly in waters from lower landscape positions. Overall, aquatic ecosystems exhibited higher NO3: NH4 ratios than soil extractions, and increasing NO3: NH4 downslope. These results suggest significant export of nitrogen after fire and the potential for nitrification as N is transported across the landscape. These changes in N cycling are likely to have substantial consequences for the recovery of plant communities post-fire and for microbial processes and greenhouse gas fluxes, including N2O, from burned watersheds.

Relationships among particle number, surface area, and respirable mass concentrations in automotive engine manufacturing.

PubMed

Heitbrink, William A; Evans, Douglas E; Ku, Bon Ki; Maynard, Andrew D; Slavin, Thomas J; Peters, Thomas M

2009-01-01

This study investigated the relationships between particle number, surface area, and respirable mass concentration measured simultaneously in a foundry and an automotive engine machining and assembly center. Aerosol concentrations were measured throughout each plant with a condensation particle counter for number concentration, a diffusion charger for active surface area concentration, and an optical particle counter for respirable mass concentration. At selected locations, particle size distributions were characterized with the optical particle counter and an electrical low pressure impactor. Statistical analyses showed that active surface area concentration was correlated with ultrafine particle number concentration and weakly correlated with respirable mass concentration. Correlation between number and active surface area concentration was stronger during winter (R2 = 0.6 for both plants) than in the summer (R2 = 0.38 and 0.36 for the foundry and engine plant respectively). The stronger correlation in winter was attributed to use of direct-fire gas fired heaters that produced substantial numbers of ultrafine particles with a modal diameter between 0.007 and 0.023 mu m. These correlations support findings obtained through theoretical analysis. Such analysis predicts that active surface area increasingly underestimates geometric surface area with increasing particle size, particularly for particles larger than 100 nm. Thus, a stronger correlation between particle number concentration and active surface area concentration is expected in the presence of high concentrations of ultrafine particles. In general, active surface area concentration may be a concentration metric that is distinct from particle number concentration and respirable mass concentration. For future health effects or toxicological studies involving nano-materials or ultrafine aerosols, this finding needs to be considered, as exposure metrics may influence data interpretation.

Impacts of a Nanosized Ceria Additive on Diesel Engine Emissions of Particulate and Gaseous Pollutants

PubMed Central

Zhang, Junfeng; Nazarenko, Yevgen; Zhang, Lin; Calderon, Leonardo; Lee, Ki-Bum; Garfunkel, Eric; Schwander, Stephan; Tetley, Teresa D.; Chung, Kian Fan; Porter, Alexandra E.; Ryan, Mary; Kipen, Howard; Lioy, Paul J.; Mainelis, Gediminas

2014-01-01

Fuel additives incorporating nanosized ceria have been increasingly used in diesel engines as combustion promoters. However, few studies have assessed the impact of these nanotechnology-based additives on pollutant emissions. Here, we systematically compare emission rates of particulate and gaseous pollutants from a single-cylinder, four-cycle diesel engine using fuel mixes containing nanoceria of varying concentrations. The test fuels were made by adding different amounts of a commercial fuel additive Envirox into an ultralow-sulfur diesel fuel at 0 (base fuel), 0.1-, 1-, and 10-fold the manufacturer-recommended concentration of 0.5 mL Envirox per liter of fuel. The addition of Envirox resulted in ceria-concentration-dependent emission reductions of CO2, CO, total particulate mass, formaldehyde, acetaldehyde, acrolein, and several polycyclic aromatic hydrocarbons. These reductions at the manufacturer-recommended doping concentration, however, were accompanied by a substantial increase of certain other air pollutants, specifically the number of ultrafine particles (+32%), NOx (+9.3%), and the particle-phase benzo[a]pyrene toxic equivalence quotient (+35%). Increasing fuel ceria concentrations also led to decreases in the size of emitted particles. Given health concerns related to ultrafine particles and NOx, our findings call for additional studies to further evaluate health risks associated with the use of nanoceria additives in various engines under various operating conditions. PMID:24144266

Quantification of Estradiol Uptake in Zebrafish Embryos and Larvae.

PubMed

Souder, Jaclyn Paige; Gorelick, Daniel A

2017-08-01

Zebrafish are a powerful model system to assess the molecular and cellular effects of exposure to toxic chemicals during embryonic development. To study the effects of environmental endocrine disruptors, embryos and larvae are commonly exposed to supraphysiologic concentrations of these compounds in the water, but their bioavailability in zebrafish is largely unknown. One hypothesis is that supraphysiologic concentrations of estrogens in the water are required to achieve physiologic levels in vivo; however, this has not been directly tested. To test this hypothesis, we developed an assay using radiolabeled estradiol ([3H]E2) to measure uptake from water at multiple concentrations and exposure durations in developing zebrafish from 0 to 5 days postfertilization (dpf). We found that [3H]E2 uptake increased with increasing concentration, duration, and developmental stage. Percent uptake from the total volume of treatment solution increased with increasing exposure duration and developmental stage, but remained constant with increasing concentration. We also found that the chorion, an acellular envelope surrounding embryos through 3 dpf, did not substantially affect [3H]E2 uptake. Finally, we found that at 1 dpf, E2 was preferentially taken up by the yolk at multiple exposure durations, while at 2 dpf E2 was preferentially taken up into the embryonic body. Our results support the hypothesis that exposing zebrafish embryos and larvae to supraphysiologic concentrations of estrogens is required to achieve physiologically relevant doses in vivo. The isotopic assay reported here will provide a foundation for determining the uptake of other compounds for teratogenicity, toxicology and drug discovery studies. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Millennial-scale iron fertilization of the eastern equatorial Pacific over the past 100,000 years

NASA Astrophysics Data System (ADS)

Loveley, Matthew R.; Marcantonio, Franco; Wisler, Marilyn M.; Hertzberg, Jennifer E.; Schmidt, Matthew W.; Lyle, Mitchell

2017-10-01

The eastern equatorial Pacific Ocean plays a crucial role in global climate, as it is a substantial source of CO2 to the atmosphere and accounts for a significant portion of global new export productivity. Here we present a 100,000-year sediment core from the eastern equatorial Pacific, and reconstruct dust flux, export productivity and bottom-water oxygenation using excess-230Th-derived fluxes of 232Th and barium, and authigenic uranium concentrations, respectively. We find that during the last glacial period (71,000 to 41,000 years ago), increased delivery of dust to the eastern equatorial Pacific was coeval with North Atlantic Heinrich stadial events. Millennial-scale pulses of increased dust flux coincided with episodes of heightened biological productivity, suggesting that dissolution of dust released iron that promoted ocean fertilization. We also find that periods of low atmospheric CO2 concentrations were associated with suboxic conditions and increased storage of respired carbon in the deep eastern equatorial Pacific. Increases in CO2 concentrations during the deglaciation are coincident with increases in deep Pacific and Southern Ocean water oxygenation levels. We suggest that deep-ocean ventilation was a primary control on CO2 outgassing in this region, with superimposed pulses of high productivity providing a negative feedback.

Boron toxicity is alleviated by hydrogen sulfide in cucumber (Cucumis sativus L.) seedlings.

PubMed

Wang, Bao-Lan; Shi, Lei; Li, Yin-Xing; Zhang, Wen-Hao

2010-05-01

Boron (B) is an essential micronutrient for plants, which when occurs in excess in the growth medium, becomes toxic to plants. Rapid inhibition of root elongation is one of the most distinct symptoms of B toxicity. Hydrogen sulfide (H(2)S) is emerging as a potential messenger molecule involved in modulation of physiological processes in plants. In the present study, we investigated the role of H(2)S in B toxicity in cucumber (Cucumis sativus) seedlings. Root elongation was significantly inhibited by exposure of cucumber seedlings to solutions containing 5 mM B. The inhibitory effect of B on root elongation was substantially alleviated by treatment with H(2)S donor sodium hydrosulfide (NaHS). There was an increase in the activity of pectin methylesterase (PME) and up-regulated expression of genes encoding PME (CsPME) and expansin (CsExp) on exposure to high B concentration. The increase in PME activity and up-regulation of expression of CsPME and CsExp induced by high B concentration were markedly reduced in the presence of H(2)S donor. There was a rapid increase in soluble B concentrations in roots on exposure to high concentration B solutions. Treatment with H(2)S donor led to a transient reduction in soluble B concentration in roots such that no differences in soluble B concentrations in roots in the absence and presence of NaHS were found after 8 h exposure to the high concentration B solutions. These findings suggest that increases in activities of PME and expansin may underlie the inhibition of root elongation by toxic B, and that H(2)S plays an ameliorative role in protection of plants from B toxicity by counteracting B-induced up-regulation of cell wall-associated proteins of PME and expansins.

Free choline and phospholipid-bound choline concentrations in serum and dialysate during peritoneal dialysis in children and adults.

PubMed

Ilcol, Yesim Ozarda; Dönmez, Osman; Yavuz, Mahmut; Dilek, Kamil; Yurtkuran, Mustafa; Ulus, Ismail H

2002-06-01

This study tested whether continuous ambulatory peritoneal dialysis (CAPD) changes free or phospholipid-bound choline concentrations in serum or peritoneal dialysis fluid of patients with end stage renal disease (ESRD). Serum and dialysate choline and phospholipid-bound choline were measured before, during and after 6 h CAPD. Serum choline concentrations were higher in patients with ESRD compared with age-matched controls. CAPD lowered serum choline concentrations significantly although it did not influence phospholipid-bound choline. Choline accumulated in the dialysate, reaching 28.4 +/- 2.7 microM in children and 18.2 +/- 1.4 microM in adults, during six hours CAPD; phospholipid-bound choline increased to 22.9 +/- 2.5 microM and 10.8 +/- 1.4 microM in children and adults, respectively. The total daily loss of choline into the dialysate was 181 +/- 20 micromoles in children and 260 +/- 18 micromoles in adults. CAPD causes a substantial loss of choline into peritoneal dialysates and reduces serum choline concentrations significantly.

Trends in precipitation and stream-water chemistry in the northeastern United States, water years 1984-96

USGS Publications Warehouse

Clow, D.W.; Mast, M. Alisa

1999-01-01

Trends in precipitation and stream-water chemistry during water years 1984-96 were examined at eight precipitation monitoring sites and five nearby streams operated by the U.S. Geological Survey in the northeastern United States. The statistical analyses indicate the following: 1)Stream-water sulfate (SO4) concentrations decreased at seven of eight precipitation monitoring sites and in each of five streams. 2)Calcium plus magnesium (Ca + Mg) concentrations decreased at seven of eight precipitation monitoring sites and in three of five streams. 3)Precipitation acidity decreased at five of eight precipitation monitoring sites, but alkalinity increased in only one stream. These results indicate that decreases in atmospheric deposition of SO4 have resulted in decreased precipitation acidity. The chemical response of stream water to changes in precipitation chemistry was complex. Decreases in stream-water SO4 concentrations generally matched decreases of precipitation SO4. In stream water, increases in alkalinity were uncommon because decreases in SO4 concentrations often were accompanied by decreases in Ca + Mg concentrations. The decreases in Ca + Mg concentrations might be related to depletion of base cations from soil caused by long-term exposure to acidic deposition. Increases in streamwater alkalinity might not occur until rates of acidic deposition are reduced to substantially less than the rate of cation resupply by weathering and atmospheric deposition. In areas where forests are aggrading, recovery of stream-water alkalinity will be delayed further because of the acidifying effect of biomass accumulation.

Effects of oxytetracycline on archaeal community, and tetracycline resistance genes in anaerobic co-digestion of pig manure and wheat straw.

PubMed

Wang, Xiaojuan; Pan, Hongjia; Gu, Jie; Qian, Xun; Gao, Hua; Qin, Qingjun

2016-12-01

In this study, the effects of different concentrations of oxytetracycline (OTC) on biogas production, archaeal community structure, and the levels of tetracycline resistance genes (TRGs) were investigated in the anaerobic co-digestion products of pig manure and wheat straw. PCR denaturing gradient gel electrophoresis analysis and real-time quantitative polymerase chain reaction (RT-qPCR) (PCR) were used to detect the archaeal community structure and the levels of four TRGs: tet(M), tet(Q), tet(W), and tet(C). The results showed that anaerobic co-digestion with OTC at concentrations of 60, 100, and 140 mg/kg (dry weight of pig manure) reduced the cumulative biogas production levels by 9.9%, 10.4%, and 14.1%, respectively, compared with that produced by the control, which lacked the antibiotic. The addition of OTC substantially modified the structure of the archaeal community. Two orders were identified by phylogenetic analysis, that is, Pseudomonadales and Methanomicrobiales, and the methanogen present during anaerobic co-digestion with OTC may have been resistant to OTC. The abundances of tet(Q) and tet(W) genes increased as the OTC concentration increased, whereas the abundances of tet(M) and tet(C) genes decreased as the OTC concentration increased.

The evaluation of zinc and copper content in tooth enamel without any pathological changes - an in vitro study.

PubMed

Klimuszko, Elzbieta; Orywal, Karolina; Sierpinska, Teresa; Sidun, Jarosław; Golebiewska, Maria

2018-01-01

The objectives of the study were to evaluate the content of copper and zinc in individual layers of tooth enamel and to analyze the relationships between the study minerals in individual layers of tooth enamel. Fifteen human permanent teeth were cut off every 150 μm alongside the labial surface. Acid biopsy of each layer was performed. The zinc content was determined using the air-acetylene flame method. The copper content was determined using the electrothermal technique with argon. The mean zinc concentrations increased significantly starting from the outer enamel surface, with the maximum concentration in the 150-300 μm layer. The mean copper concentrations increased substantially from the outer enamel surface to a depth of 150 μm, and then a slight downward trend of this mineral levels was seen, down to a depth of 450 μm. Strong positive correlation was found between the zinc and copper concentrations at depths of 150-300, 450-600 and 600-750 μm. The levels of zinc and copper in the outer enamel layers may have an effect on the increased content of unipolar minerals at deeper enamel layers. The content of the study elements determined may reflect the process of mineralization and maturation of enamel in the pre-eruption period.

Response of soil microbial communities to roxarsone pollution along a concentration gradient.

PubMed

Liu, Yaci; Zhang, Zhaoji; Li, Yasong; Wen, Yi; Fei, Yuhong

2017-07-29

The extensive use of roxarsone (3-nitro-4-hydroxyphenylarsonic acid) as a feed additive in the broiler poultry industry can lead to environmental arsenic contamination. This study was conducted to reveal the response of soil microbial communities to roxarsone pollution along a concentration gradient. To explore the degradation process and degradation kinetics of roxarsone concentration gradients in soil, the concentration shift of roxarsone at initial concentrations of 0, 50, 100, and 200 mg/kg, as well as that of the arsenic derivatives, was detected. The soil microbial community composition and structure accompanying roxarsone degradation were investigated by high-throughput sequencing. The results showed that roxarsone degradation was inhibited by a biological inhibitor, confirming that soil microbes were absolutely essential to its degradation. Moreover, soil microbes had considerable potential to degrade roxarsone, as a high initial concentration of roxarsone resulted in a substantially increased degradation rate. The concentrations of the degradation products HAPA (3-amino-4-hydroxyphenylarsonic acid), AS(III), and AS(V) in soils were significantly positively correlated. The soil microbial community composition and structure changed significantly across the roxarsone contamination gradient, and the addition of roxarsone decreased the microbial diversity. Some bacteria tended to be inhibited by roxarsone, while Bacillus, Paenibacillus, Arthrobacter, Lysobacter, and Alkaliphilus played important roles in roxarsone degradation. Moreover, HAPA, AS(III), and AS(V) were significantly positively correlated with Symbiobacterium, which dominated soils containing roxarsone, and their abundance increased with increasing initial roxarsone concentration. Accordingly, Symbiobacterium could serve as indicator of arsenic derivatives released by roxarsone as well as the initial roxarsone concentration. This is the first investigation of microbes closely related to roxarsone degradation.

Estimation of ultrafine particle concentrations at near-highway residences using data from local and central monitors

PubMed Central

Fuller, Christina H.; Brugge, Doug; Williams, Paige; Mittleman, Murray; Durant, John L.; Spengler, John D.

2012-01-01

Ultrafine particles (UFP; aerodynamic diameter < 0.1 micrometers) are a ubiquitous exposure in the urban environment and are elevated near highways. Most epidemiological studies of UFP health effects use central site monitoring data, which may misclassify exposure. Our aims were to: (1) examine the relationship between distant and proximate monitoring sites and their ability to predict hourly UFP concentration measured at residences in an urban community with a major interstate highway and; (2) determine if meteorology and proximity to traffic improve explanatory power. Short-term (1 – 3 weeks) residential monitoring of UFP concentration was conducted at 18 homes. Long-term monitoring was conducted at two near-highway monitoring sites and a central site. We created models of outdoor residential UFP concentration based on concentrations at the near-highway site, at the central site, at both sites together and without fixed sites. UFP concentration at residential sites was more highly correlated with those at a near-highway site than a central site. In regression models of each site alone, a 10% increase in UFP concentration at a near-highway site was associated with a 6% (95% CI: 6%, 7%) increase at residences while a 10% increase in UFP concentration at the central site was associated with a 3% (95% CI: 2%, 3%) increase at residences. A model including both sites showed minimal change in the magnitude of the association between the near-highway site and the residences, but the estimated association with UFP concentration at the central site was substantially attenuated. These associations remained after adjustment for other significant predictors of residential UFP concentration, including distance from highway, wind speed, wind direction, highway traffic volume and precipitation. The use of a central site as an estimate of personal exposure for populations near local emissions of traffic-related air pollutants may result in exposure misclassification. PMID:23645993

Estimation of ultrafine particle concentrations at near-highway residences using data from local and central monitors.

PubMed

Fuller, Christina H; Brugge, Doug; Williams, Paige; Mittleman, Murray; Durant, John L; Spengler, John D

2012-09-01

Ultrafine particles (UFP; aerodynamic diameter < 0.1 micrometers) are a ubiquitous exposure in the urban environment and are elevated near highways. Most epidemiological studies of UFP health effects use central site monitoring data, which may misclassify exposure. Our aims were to: (1) examine the relationship between distant and proximate monitoring sites and their ability to predict hourly UFP concentration measured at residences in an urban community with a major interstate highway and; (2) determine if meteorology and proximity to traffic improve explanatory power. Short-term (1 - 3 weeks) residential monitoring of UFP concentration was conducted at 18 homes. Long-term monitoring was conducted at two near-highway monitoring sites and a central site. We created models of outdoor residential UFP concentration based on concentrations at the near-highway site, at the central site, at both sites together and without fixed sites. UFP concentration at residential sites was more highly correlated with those at a near-highway site than a central site. In regression models of each site alone, a 10% increase in UFP concentration at a near-highway site was associated with a 6% (95% CI: 6%, 7%) increase at residences while a 10% increase in UFP concentration at the central site was associated with a 3% (95% CI: 2%, 3%) increase at residences. A model including both sites showed minimal change in the magnitude of the association between the near-highway site and the residences, but the estimated association with UFP concentration at the central site was substantially attenuated. These associations remained after adjustment for other significant predictors of residential UFP concentration, including distance from highway, wind speed, wind direction, highway traffic volume and precipitation. The use of a central site as an estimate of personal exposure for populations near local emissions of traffic-related air pollutants may result in exposure misclassification.

High-performance reagent modes for flotation recovery of platiniferous copper and nickel sulfides from hard-to-beneficiate ores

NASA Astrophysics Data System (ADS)

Matveeva, T. N.; Chanturiya, V. A.

2017-07-01

The paper presents the results of the recent research performed in IPKON Russian Academy of Sciences that deals with development and substantiation of new selective reagents for effective flotation recovery of non-ferrous and noble metals from refractory ores. The choice and development of new selective reagents PTTC, OPDTC, modified butylxanthate (BXm) and modified diethyl-dithiocarbamate (DEDTCm) to float platiniferous copper and nickel sulfide minerals from hard-to-beneficiate ores is substantiated. The mechanism of reagents adsorption and regulation of minerals floatability is discussed. The study of reagent modes indicates that by combining PTTC with the modified xanthate results in 6 - 7 % increase in the recovery of copper, nickel and PGM in the flotation of the low-sulfide platiniferous Cu-Ni ore from the Fedorovo-Panskoye deposit. The substitution of OPDTC for BX makes it possible to increase recovery of Pt by 13 %, Pd by 9 % and 2 - 4 times the noble metal content in the flotation concentrate.

Solution Behavior and Activity of a Halophilic Esterase under High Salt Concentration

PubMed Central

Rao, Lang; Zhao, Xiubo; Pan, Fang; Li, Yin; Xue, Yanfen; Ma, Yanhe; Lu, Jian R.

2009-01-01

Background Halophiles are extremophiles that thrive in environments with very high concentrations of salt. Although the salt reliance and physiology of these extremophiles have been widely investigated, the molecular working mechanisms of their enzymes under salty conditions have been little explored. Methodology/Principal Findings A halophilic esterolytic enzyme LipC derived from archeaon Haloarcula marismortui was overexpressed from Escherichia coli BL21. The purified enzyme showed a range of hydrolytic activity towards the substrates of p-nitrophenyl esters with different alkyl chains (n = 2−16), with the highest activity being observed for p-nitrophenyl acetate, consistent with the basic character of an esterase. The optimal esterase activities were found to be at pH 9.5 and [NaCl] = 3.4 M or [KCl] = 3.0 M and at around 45°C. Interestingly, the hydrolysis activity showed a clear reversibility against changes in salt concentration. At the ambient temperature of 22°C, enzyme systems working under the optimal salt concentrations were very stable against time. Increase in temperature increased the activity but reduced its stability. Circular dichroism (CD), dynamic light scattering (DLS) and small angle neutron scattering (SANS) were deployed to determine the physical states of LipC in solution. As the salt concentration increased, DLS revealed substantial increase in aggregate sizes, but CD measurements revealed the maximal retention of the α-helical structure at the salt concentration matching the optimal activity. These observations were supported by SANS analysis that revealed the highest proportion of unimers and dimers around the optimal salt concentration, although the coexistent larger aggregates showed a trend of increasing size with salt concentration, consistent with the DLS data. Conclusions/Significance The solution α-helical structure and activity relation also matched the highest proportion of enzyme unimers and dimers. Given that all the solutions studied were structurally inhomogeneous, it is important for future work to understand how the LipC's solution aggregation affected its activity. PMID:19759821

Rheology of concentrated suspensions of non-colloidal rigid fibers

NASA Astrophysics Data System (ADS)

Guazzelli, Elisabeth; Tapia, Franco; Shaikh, Saif; Butler, Jason E.; Pouliquen, Olivier

2017-11-01

Pressure and volume-imposed rheology is used to study suspensions of non-colloidal, rigid fibers in the concentrated regime for aspect ratios ranging from 3 to 15. The suspensions exhibit yield-stresses. Subtracting these apparent yield-stresses reveals a viscous scaling for both the shear and normal stresses. The variation in aspect ratio does not affect the friction coefficient (ratio of shear and normal stresses), but increasing the aspect ratio lowers the maximum volume fraction at which the suspension flows. Constitutive laws are proposed for the viscosities and the friction coefficient close to this maximum flowable fraction. The scaling of the stresses near this jamming transition are found to differ substantially from that of a suspension of spheres.

Indoor, outdoor, and regional summer and winter concentrations of PM10, PM2.5, SO4(2)-, H+, NH4+, NO3-, NH3, and nitrous acid in homes with and without kerosene space heaters.

PubMed Central

Leaderer, B P; Naeher, L; Jankun, T; Balenger, K; Holford, T R; Toth, C; Sullivan, J; Wolfson, J M; Koutrakis, P

1999-01-01

Twenty-four-hour samples of PM10 (mass of particles with aerodynamic diameter < or = 10 microm), PM2.5, (mass of particles with aerodynamic diameter < or = 2.5 microm), particle strong acidity (H+), sulfate (SO42-), nitrate (NO3-), ammonia (NH3), nitrous acid (HONO), and sulfur dioxide were collected inside and outside of 281 homes during winter and summer periods. Measurements were also conducted during summer periods at a regional site. A total of 58 homes of nonsmokers were sampled during the summer periods and 223 homes were sampled during the winter periods. Seventy-four of the homes sampled during the winter reported the use of a kerosene heater. All homes sampled in the summer were located in southwest Virginia. All but 20 homes sampled in the winter were also located in southwest Virginia; the remainder of the homes were located in Connecticut. For homes without tobacco combustion, the regional air monitoring site (Vinton, VA) appeared to provide a reasonable estimate of concentrations of PM2.5 and SO42- during summer months outside and inside homes within the region, even when a substantial number of the homes used air conditioning. Average indoor/outdoor ratios for PM2.5 and SO42- during the summer period were 1.03 +/- 0.71 and 0.74 +/- 0.53, respectively. The indoor/outdoor mean ratio for sulfate suggests that on average approximately 75% of the fine aerosol indoors during the summer is associated with outdoor sources. Kerosene heater use during the winter months, in the absence of tobacco combustion, results in substantial increases in indoor concentrations of PM2.5, SO42-, and possibly H+, as compared to homes without kerosene heaters. During their use, we estimated that kerosene heaters added, on average, approximately 40 microg/m3 of PM2.5 and 15 microg/m3 of SO42- to background residential levels of 18 and 2 microg/m3, respectively. Results from using sulfuric acid-doped Teflon (E.I. Du Pont de Nemours & Co., Wilmington, DE) filters in homes with kerosene heaters suggest that acid particle concentrations may be substantially higher than those measured because of acid neutralization by ammonia. During the summer and winter periods indoor concentrations of ammonia are an order of magnitude higher indoors than outdoors and appear to result in lower indoor acid particle concentrations. Nitrous acid levels are higher indoors than outdoors during both winter and summer and are substantially higher in homes with unvented combustion sources. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:10064553

Preliminary Report on Floodplain Animals of the Upper Mississippi River and the Illinois Waterway Including Some Probable Impacts of Increased Commercial Traffic,

DTIC Science & Technology

1975-01-01

case of the canvasback, it is conceivable that a large oil spill in a concentration area during the peak migration period could destroy a substantial...winter crowned Lichtenstein secondary resident kinglet succession 123. Ruby-crowned Regulus calendula Statewide Statewide younger stand, C winter...Regulus calendula . Ruby-crowned Kinglet TV-c Family MOTACLLLIDAS - pipits Anthus spinoletta ’Water Pipit, TV-r Family BOHIYCILLIDAE - waxwings

Arsenic Remediation Enhancement Through Chemical Additions to Pump and Treat Operations

NASA Astrophysics Data System (ADS)

Wovkulich, K.; Mailloux, B. J.; Stute, M.; Simpson, H. J.; Keimowitz, A. R.; Powell, A.; Lacko, A.; Chillrud, S. N.

2008-12-01

Arsenic is a contaminant found at more than 500 US Superfund sites. Since pump and treat technologies are widely used for remediation of contaminated groundwater, increasing the efficiency of contaminant removal at such sites should allow limited financial resources to clean up more sites. The Vineland Chemical Company Superfund site is extensively contaminated with arsenic after waste arsenic salts were stored and disposed of improperly for much of the company's 44 year manufacturing lifetime. Despite approximately eight years of pump and treat remediation, arsenic concentrations in the recovery wells can still be greater than 1000 ppb. The arsenic concentrations in the groundwater remain high because of slow desorption of arsenic from contaminated aquifer solids. Extrapolation of laboratory column experiments suggest that continuing the current groundwater remediation practice based on flushing ambient groundwater through the system may require on the order of hundreds of years to clean the site. However, chemical additions of phosphate or oxalic acid into the aquifer could decrease the remediation time scale substantially. Laboratory results from a soil column experiment using input of 10 mM oxalic acid suggest that site clean up of groundwater could be decreased to as little as four years. Pilot scale forced gradient field experiments will help establish whether chemical additions can be effective for increasing arsenic mobilization from aquifer solids and thus substantially decrease pump and treat clean up time.

Wildfire Effects on In-stream Nutrient Processing and Hydrologic Transport

NASA Astrophysics Data System (ADS)

Rhea, A.; Covino, T. P.; Rhoades, C.; Fegel, T.

2017-12-01

In many forests throughout the Western U.S., drought, climate change, and growing fuel loads are contributing to increased fire frequency and severity. Wildfires can influence watershed nutrient retention as they fundamentally alter the biological composition and physical structure in upland landscapes, riparian corridors, and stream channels. While numerous studies have documented substantial short-term increases in stream nutrient concentrations and export (particularly reactive nitrogen, N) following forest fires, the long-term implications for watershed nutrient cycling remain unclear. For example, recent work indicates that nitrate concentrations and export can remain elevated for a decade or more following wildfire, yet the controls on these processes are unknown. In this research, we use empirical observations from nutrient tracer injections, nutrient diffusing substrates, and continuous water quality monitoring to isolate biological and physical controls on nutrient export across a burn-severity gradient. Tracer results demonstrate substantial stream-groundwater exchange, but little biological nutrient uptake in burned streams. This in part explains patterns of elevated nutrient export. Paired nutrient diffusing substrate experiments allow us to further investigate shifts in N, phosphorus, and carbon limitation that may suppress post-fire stream nutrient uptake. By isolating the mechanisms that reduce the capacity of fire-affected streams to retain and transform nutrient inputs, we can better predict dynamics in post-fire water quality and help prioritize upland and riparian restoration.

Effect of grape bunch sunlight exposure and UV radiation on phenolics and volatile composition of Vitis vinifera L. cv. Pinot noir wine.

PubMed

Song, Jianqiang; Smart, Richard; Wang, Hua; Dambergs, Bob; Sparrow, Angela; Qian, Michael C

2015-04-15

The effect of canopy leaf removal and ultraviolet (UV) on Pinot noir grape and wine composition was investigated in this study. Limited basal leaf removal in the fruit zone was conducted, compared to shaded bunches. The UV exposure was controlled using polycarbonate screens to block UV radiation, and acrylic screens to pass the UV. The results showed that bunch sunlight and UV exposure significantly increased the Brix and pH in the grape juice, and increased substantially wine colour density, anthocyanins, total pigment, total phenolics and tannin content. Bunch sunlight and UV exposure affected terpene alcohols, C13-norisprenoids and other volatile composition of the wine differently. Sunlight exposure and UV resulted in increase of nerol, geraniol and citronellol but not linalool. Sunlight exposure slightly increased the concentration of β-ionone, but the increase was not statistically significant for UV treatment. Neither sunlight nor UV treatment showed any impact on the concentration of β-damascenone. Copyright © 2014 Elsevier Ltd. All rights reserved.

Does the responses of Vallisneria natans (Lour.) Hara to high nitrogen loading differ between the summer high-growth season and the low-growth season?

PubMed

Yu, Qing; Wang, Hai-Jun; Wang, Hong-Zhu; Li, Yan; Liang, Xiao-Min; Xu, Chi; Jeppesen, Erik

2017-12-01

Loss of submersed macrophytes is a world-wide phenomenon occurring when shallow lakes become eutrophic due to excess nutrient loading. In addition to the well-known effect of phosphorus, nitrogen as a trigger of macrophyte decline has received increasing attention. The precise impact of high nitrogen concentrations is debated, and the role of different candidate factors may well change over the season. In this study, we conducted experiments with Vallisneria natans during the growing season (June-September) in 10 ponds subjected to substantial differences in nitrogen loading (five targeted total nitrogen concentrations: control, 2, 10, 20, and 100mgL -1 ) and compared the results with those obtained in our earlier published study from the low-growth season (December-April). Like in the low-growth season, growth of V. natans in summer declined with increasing ammonium (NH 4 ) concentrations and particularly with increasing phytoplankton chlorophyll a (Chla Phyt ). Accordingly, we propose that shading by phytoplankton might be of key importance for macrophyte decline, affecting also periphyton growth as periphyton chlorophyll a (Chla Peri ) decreased with increasing Chla Phyt . Free amino acid contents (FAA) of plants tended to increase with increasing NH 4 concentrations, while the relationships between FAA with growth indices were all weak, suggesting that FAA might be a useful indicator of the physiological stress of the plants but not of macrophyte growth. Taken together, the results from the two seasons indicate that although a combination of high nitrogen concentrations (ammonium) and shading by phytoplankton may cause severe stress on macrophytes, active growth in the growing season enabled them to partly overcome the stress. Copyright © 2017 Elsevier B.V. All rights reserved.

An initial examination of tungsten geochemistry along groundwater flow paths

NASA Astrophysics Data System (ADS)

Dave, H. B.; Johannesson, K. H.

2008-12-01

Groundwater samples were collected along groundwater flow paths from the Upper Floridan (Florida), Carrizo Sand (Texas), and the Aquia (Maryland) aquifers and analyzed for tungsten (W) concentrations by high- resolution inductively couple plasma mass spectrometry. At each well head, groundwater samples were also analyzed for pH, specific conductance, temperature, alkalinity, dissolved oxygen (DO), oxidation-reduction potential (Eh), dissolved iron speciation, and dissolved sulfide [S(-II)] concentrations. Sediment samples from the Carrizo Sand and Aquia aquifers were also collected and subjected to sequential extractions to provide additional insights into the solid-phase speciation of W in these aquifers. Tungsten concentrations varied along the groundwater flow paths chiefly in response to changing pH, and to a lesser extent, variations in the redox conditions. For groundwater from the Carrizo Sand aquifer, W ranges between 3.64 and 1297 pmol/kg, exhibiting the lowest values proximal to the recharge zone. Tungsten concentrations progressively increase along the flow path, reaching 1297 pmol/kg in the sulfidic groundwaters located approximately 60 km downgradient from the recharge area. Tungsten is strongly correlated with S(-II) concentrations and pH in Carrizo groundwaters (r = 0.95 and 0.78, respectively). Within the Aquia aquifer, however, W generally occurs at lower concentrations than the Carrizo (14 to 184 pmol/kg; mean = 80 pmol/kg), and shows no systematic trends along the flow path (e.g., r = 0.08 and 0.4 for W vs. S(-II) and pH, respectively). Our data are consistent with the increase in W concentrations in Carrizo groundwaters reflecting, in part, pH-related desorption, which has been shown to be substantial for pH greater than 8. Moreover, because of the broad similarities in the chemistry of W and Mo, which forms thiomolybdates in sulfidic waters, we suggest that thiotungstate complexes may form in sulfidic groundwaters, thus partially explaining the elevated W in sulfidic waters of the Carrizo aquifer. We propose that the substantially lower W concentrations in Aquia groundwaters reflect the fact that these waters are suboxic and have not undergone sulfate reduction. Hence, the evolution of W concentrations in the Aquia aquifer is consistent with conservative behavior in these generally oxic to suboxic groundwaters. In summary, our data indicate that pH related adsorption/desorption reactions are the key factors controlling W concentrations in oxic and sub-oxic waters, whereas formation of thiotungstate complexes may be important in sulfidic/anoxic waters.

Nitrous Oxide Emissions in a Managed Grassland are Strongly Influenced by CO2 Concentrations Across a Range of Soil Moisture Levels

NASA Astrophysics Data System (ADS)

Brown, Z. A.; Hovenden, M. J.; Hunt, M.

2017-12-01

Though the atmosphere contains less nitrous oxide (N2O, 324 ppb) than carbon dioxide (CO2, 400 ppm­), N2O has 298 times the global warming potential of CO2 on a 100-year horizon. Nitrous oxide emissions tend to be greater in moist soils because denitrification is an anaerobic process. The rising concentration of CO2 in the atmosphere reduces plant stomatal aperture, thereby slowing transpiration and water use and leading to higher soil moisture levels. Thus, the rising CO2 concentration could stimulate N2O emissions indirectly via increasing soil moisture. Further, results from field experiments in which CO2 is elevated have demonstrated nitrification is accelerated at elevated CO2 concentrations (eCO2). Hence, N2O emissions could be substantially increased by the impacts of rising CO2 concentrations on plant and ecosystem physiology. However, the scale of this impact could be influenced by the amount of water supplied through irrigation or rainfall since both nitrification and denitrification are sensitive to soil moisture. Here, we use measurements of CO2 and N2O emissions from the TasFACE2 experiment to explore the ways in which the impact of CO2 concentration on greenhouse gas emissions is influenced by water supply in a managed temperate pasture. TasFACE2 is the world's only experiment that explicitly controls soil water availability at three different CO2 concentrations. Application of chemical nitrification inhibitor severely reduces N2O flux from soils regardless of CO2 level, water treatment and time following urea application. This inhibitor reduced soil respiration in plots exposed to ambient CO2 plots but not in eCO2 plots. N2O flux is stimulated by eCO2 but not consistently among watering treatments or seasons. Soil respiration is strongly enhanced by CO2 effect regardless of watering treatment. The results demonstrate that CO2 concentration has a sustained impact on CO2 and N2O flux across a range of water availabilities in this fertilised, ryegrass pasture. Thus, the impacts of rising CO2 concentrations on greenhouse gas emissions are not dependent upon soil water availability, with substantial impacts occurring even in drier soils. Thus, the impact of CO2 concentration on emissions might be stronger than has been believed to this point, with major ramifications for future climate.

Selective killing of proinflammatory synovial fibroblasts via activation of transient receptor potential ankyrin (TRPA1).

PubMed

Lowin, Torsten; Bleck, Janna; Schneider, Matthias; Pongratz, Georg

2018-05-24

Studies in rheumatoid arthritis synovial fibroblasts (RASF) demonstrated the expression of several transient receptor potential channels (TRP) such as TRPV1, TRPV2, TRPV4, TRPA1 and TRPM8. Upon ligation, these receptors increase intracellular calcium but they have also been linked to modulation of inflammation in several cell types. TNF was shown to increase the expression of TRPA1, the receptor for mustard oil and environmental poisons in SF, but the functional consequences have not been investigated yet. TRPA1 was detected by immunocytochemistry, western blot and cell-based ELISA. Calcium measurements were conducted in a multimode reader. Cell viability was assessed by quantification of lactate dehydrogenase (LDH) in culture supernatants and "RealTime-Glo" luminescent assays. IL-6 and IL-8 production by SF was quantified by ELISA. Proliferation was determined by cell titer blue incorporation. After 72 h, mimicking proinflammatory conditions by the innate cytokine TNF up-regulated TRPA1 protein levels in RASF which was accompanied by increased sensitivity to TRPA1 agonists AITC and polygodial. Under unstimulated conditions, polygodial elicited calcium flux only in the highest concentrations used (50 µM and 25 µM). TNF preincubation substantially lowered the activation threshold for polygodial (from 25 µM to 1 µM). In the absence of TNF pre-stimulation, only polygodial in high concentrations was able to reduce viability of synovial fibroblasts as determined by a real-time viability assay. However, following TNF preincubation, stimulation of TRPA1 led to a fast (<30 min) viability loss by necrosis of synovial fibroblasts. TRPA1 activation was also associated with decreased proliferation of RASFs, an effect that was also substantially enhanced by TNF preincubation. On the functional level, IL-6 and IL-8 production was attenuated by the TRPA1 antagonist A967079 but also polygodial, although the latter mediated this effect by reducing cell viability. Simulating inflamed conditions by preincubation of synovial fibroblasts with TNF up-regulates and sensitizes TRPA1. Subsequent activation of TRPA1 increases calcium flux and substantially reduces cell viability by inducing necrosis. Since TRPA1 agonists in the lower concentration range only show effects in TNF-stimulated RASF, this cation channel might be an attractive therapeutic target in chronic inflammation to selectively reduce the activity of proinflammatory SF in the joint. Copyright © 2018 Elsevier Inc. All rights reserved.

Adult vaccination against tetanus and diphtheria: the European perspective

PubMed Central

2016-01-01

Summary Besides immunizations against influenza, Streptococcus pneumoniae and herpes zoster, which are recommended specifically for elderly people, regular booster vaccinations against tetanus, diphtheria and in some cases pertussis and polio are recommended in many European countries for adults, including elderly people. Vaccination recommendations for adults differ greatly between individual countries and coverage data is scarce. Tetanus‐specific antibody concentrations are generally higher than diphtheria‐specific antibodies, and a substantial proportion of adults, and particularly of elderly people, do not have protective antibody concentrations against diphtheria. Antibody levels increase upon booster vaccination in all age groups, but diphtheria‐specific antibody concentrations remain below protective levels in some older individuals, even immediately after vaccination and long‐term protection is frequently not achieved. Future vaccination strategies should therefore include regular and well‐documented booster shots, e.g. against tetanus and diphtheria, throughout life. PMID:27279025

Variation in the concentration and age of nonstructural carbon stored in different tree tissues

NASA Astrophysics Data System (ADS)

Richardson, Andrew; Carbone, Mariah; Huggett, Brett; Furze, Morgan; Czimczik, Claudia I.; Xu, Xiaomei

2014-05-01

Trees store nonstructural carbon (NSC), in the form of sugars and starch, in the ray parenchyma cells of woody tissues. These reserves provide a carbon buffer when demand (growth, protection, or metabolism) exceeds supply (photosynthesis). This is particularly important in the context of resilience to stress and disturbance, such as might be associated with various global change factors. However, storage allocation processes and the availability of stored reserves remain poorly understood in woody plants. To better understand how NSC reserves are distributed throughout the tree, and the degree to which NSC reserves mix across ring boundaries and tissue types, we destructively sampled two 30-year-old trees (one red oak, Quercus rubra L., and one white pine, Pinus strobus L.) growing at Harvard Forest, an oak-dominated temperate forest in the northeastern United States. We analyzed stemwood samples (divided into individual rings, bark, and phloem), coarse and fine branches, and coarse (separated into three depths) and fine roots for concentrations of total sugars and starch. For a subset of samples we used the radiocarbon (14C) "bomb spike" method to estimate the mean age of extracted sugars and starch. In oak, stemwood sugar and starch concentrations were highest (50 mg/g) in the youngest (most recently-formed) rings, and dropped off rapidly (to 10 mg/g or less) across the 10 most recent rings. In oak phloem tissue, sugar concentrations were high (90 mg/g) compared to starch (10 mg/g). In pine, sugar concentrations dropped off rapidly across the three most recent rings (from 30 mg/g to 10 mg/g) whereas starch concentrations were low even for the youngest rings (10 mg/g or less). In pine, phloem concentrations of both sugar (190 mg/g) and starch (20 mg/g) were both substantially higher than in oak. Such strong radial trends must be accounted for when scaling up to whole-tree budgets, as whole increment cores cannot properly integrate (on a ring-area basis) across the depth profile. In oak, fine root concentrations of sugar and starch were similar (40 mg/g), and coarse roots had very high concentrations of starch (140 mg/g) compared to sugar (50 mg/g). In pine, fine root concentrations of both sugar and starch (60 mg/g) were higher than in coarse roots (10 mg/g). Coarse root NSC concentrations did not vary substantially along a radial gradient into the root. Even assuming a 1:5 root:shoot ratio, these data indicate that a large portion of the whole-tree NSC budget is stored belowground. For both sugars and starch, the 14C data indicated substantial mixing of new and older carbon across the youngest stemwood rings (up to 5 y), beyond which NSC age increased linearly with ring age. Coarse root NSC age also increased with radial depth and wood tissue age, and root NSC was consistently younger in pine than oak. The fact that NSC age is not constant with radial depth in the aboveground samples demonstrates that NSC reserves cannot be treated as a single, well-mixed pool. Rather, these results are consistent with previous observation suggesting last-in/first-out dynamics. From a modeling standpoint, these results support a simple two-pool structure where new photosynthate not used for current growth or metabolism enters a well-mixed and young "fast" pool, but over time storage in older rings is transferred to a distinct and older "slow" pool with which mixing no longer occurs.

Coupled phase and aqueous species equilibrium of the H 2O-CO 2-NaCl-CaCO 3 system from 0 to 250 °C, 1 to 1000 bar with NaCl concentrations up to saturation of halite

NASA Astrophysics Data System (ADS)

Duan, Zhenhao; Li, Dedong

2008-10-01

A model is developed for the calculation of coupled phase and aqueous species equilibrium in the H 2O-CO 2-NaCl-CaCO 3 system from 0 to 250 °C, 1 to 1000 bar with NaCl concentrations up to saturation of halite. The vapor-liquid-solid (calcite, halite) equilibrium together with the chemical equilibrium of H +, Na +, Ca 2+, CaHCO3+, Ca(OH) +, OH -, Cl -, HCO3-, CO32-, CO 2(aq) and CaCO 3(aq) in the aqueous liquid phase as a function of temperature, pressure, NaCl concentrations, CO 2(aq) concentrations can be calculated, with accuracy close to those of experiments in the stated T- P- m range, hence calcite solubility, CO 2 gas solubility, alkalinity and pH values can be accurately calculated. The merit and advantage of this model is its predictability, the model was generally not constructed by fitting experimental data. One of the focuses of this study is to predict calcite solubility, with accuracy consistent with the works in previous experimental studies. The resulted model reproduces the following: (1) as temperature increases, the calcite solubility decreases. For example, when temperature increases from 273 to 373 K, calcite solubility decreases by about 50%; (2) with the increase of pressure, calcite solubility increases. For example, at 373 K changing pressure from 10 to 500 bar may increase calcite solubility by as much as 30%; (3) dissolved CO 2 can increase calcite solubility substantially; (4) increasing concentration of NaCl up to 2 m will increase calcite solubility, but further increasing NaCl solubility beyond 2 m will decrease its solubility. The functionality of pH value, alkalinity, CO 2 gas solubility, and the concentrations of many aqueous species with temperature, pressure and NaCl (aq) concentrations can be found from the application of this model. Online calculation is made available on www.geochem-model.org/models/h2o_co2_nacl_caco3/calc.php.

Addition of an organic amendment and/or residue mud to bauxite residue sand in order to improve its properties as a growth medium.

PubMed

Jones, B E H; Haynes, R J; Phillips, I R

2012-03-01

The effects of addition of carbonated residue mud (RMC) or seawater neutralized residue mud (RMS), at two rates, in the presence or absence of added green waste compost, on the chemical, physical and microbial properties of gypsum-treated bauxite residue sand were studied in a laboratory incubation study. The growth of two species commonly used in revegetation of residue sand (Lolium rigidum and Acacia saligna) in the treatments was then studied in a 18-week greenhouse study. Addition of green waste-based compost increased ammonium acetate-extractable (exchangeable) Mg, K and Na. Addition of residue mud at 5 and 10% w/w reduced exchangeable Ca but increased that of Mg and Na (and K for RMS). Concentrations of K, Na, Mg and level of EC in saturation paste extracts were increased by residue mud additions. Concentrations of cations in water extracts were considerably higher than those in saturation paste extracts but trends with treatment were broadly similar. Addition of both compost and residue mud caused a significant decrease in macroporosity with a concomitant increase in mesoporosity and microporosity, available water holding capacity and the quantity of water held at field capacity. Increasing rates of added residue mud reduced the percentage of sample present as discrete sand particles and increased that in aggregated form (particularly in the 1-2 and >10mm diameter ranges). Organic C content, C/N ratio, soluble organic C, microbial biomass C and basal respiration were increased by compost additions. Where compost was added, residue mud additions caused a substantial increase in microbial biomass and basal respiration. L. rigidum grew satisfactorily in all treatments although yields tended to be reduced by additions of mud (especially RMC) particularly in the absence of added compost. Growth of A. saligna was poor in sand alone and mud-amended sand and was greatly promoted by additions of compost. However, in the presence of compost, addition of carbonated mud had a marked depressive effect on both top and root growth. The significant positive effect of compost was attributed to substantial inputs of K and marked reductions in the Na/K ratio in soil solution while the depressive effect of RMC was attributed to its greater alkalinity and consequently higher concentrations of HCO(3)(-) in solution. Copyright © 2011 Elsevier Ltd. All rights reserved.

Reversible cluster formation in concentrated monoclonal antibody solutions

NASA Astrophysics Data System (ADS)

Godfrin, P. Douglas; Porcar, Lionel; Falus, Peter; Zarraga, Isidro; Wagner, Norm; Liu, Yun

2015-03-01

Protein cluster formation in solution is of fundamental interest for both academic research and industrial applications. Recently, industrial scientists are also exploring the effect of reversible cluster formation on biopharmaceutical processing and delivery. However, despite of its importance, the understanding of protein clusters at concentrated solutions remains scientifically very challenging. Using the neutron spin echo technique to study the short time dynamics of proteins in solutions, we have recently systematically studied cluster formation in a few monoclonal antibody (mAb) solutions and their relation with solution viscosity. We show that the existence of anisotropic attraction can cause the formation of finite sized clusters, which increases the solution viscosity. Interestingly, once clusters form at relatively low concentrations, the average size of clusters in solutions remains almost constant over a wide range of concentrations similar to that of micelle formation. For a different mAb we have also investigated, the attraction is mostly induced by hydrophobic patches. As a result, these mAbs form large clusters with loosely linked proteins. In both cases, the formation of clusters all increases the solution viscosity substantially. However, due to different physics origins of cluster formation, solutions viscosities for these two different types of mAbs need to be controlled by different ways.

Ion selectivity of the Vibrio alginolyticus flagellar motor.

PubMed Central

Liu, J Z; Dapice, M; Khan, S

1990-01-01

The marine bacterium, Vibrio alginolyticus, normally requires sodium for motility. We found that lithium will substitute for sodium. In neutral pH buffers, the membrane potential and swimming speed of glycolyzing bacteria reached maximal values as sodium or lithium concentration was increased. While the maximal potentials obtained in the two cations were comparable, the maximal swimming speed was substantially lower in lithium. Over a wide range of sodium concentration, the bacteria maintained an invariant sodium electrochemical potential as determined by membrane potential and intracellular sodium measurements. Over this range the increase of swimming speed took Michaelis-Menten form. Artificial energization of swimming motility required imposition of a voltage difference in concert with a sodium pulse. The cation selectivity and concentration dependence exhibited by the motile apparatus depended on the viscosity of the medium. In high-viscosity media, swimming speeds were relatively independent of either ion type or concentration. These facts parallel and extend observations of the swimming behavior of bacteria propelled by proton-powered flagella. In particular, they show that ion transfers limit unloaded motor speed in this bacterium and imply that the coupling between ion transfers and force generation must be fairly tight. PMID:2394685

The Effect of Climate Change on Ozone Depletion through Changes in Stratospheric Water Vapour

NASA Technical Reports Server (NTRS)

Kirk-Davidoff, Daniel B.; Hintsa, Eric J.; Anderson, James G.; Keith, David W.

1999-01-01

Several studies have predicted substantial increases in Arctic ozone depletion due to the stratospheric cooling induced by increasing atmospheric CO2 concentrations. But climate change may additionally influence Arctic ozone depletion through changes in the water vapor cycle. Here we investigate this possibility by combining predictions of tropical tropopause temperatures from a general circulation model with results from a one-dimensional radiative convective model, recent progress in understanding the stratospheric water vapor budget, modelling of heterogeneous reaction rates and the results of a general circulation model on the radiative effect of increased water vapor. Whereas most of the stratosphere will cool as greenhouse-gas concentrations increase, the tropical tropopause may become warmer, resulting in an increase of the mean saturation mixing ratio of water vapor and hence an increased transport of water vapor from the troposphere to the stratosphere. Stratospheric water vapor concentration in the polar regions determines both the critical temperature below which heterogeneous reactions on cold aerosols become important (the mechanism driving enhanced ozone depletion) and the temperature of the Arctic vortex itself. Our results indicate that ozone loss in the later winter and spring Arctic vortex depends critically on water vapor variations which are forced by sea surface temperature changes in the tropics. This potentially important effect has not been taken into account in previous scenarios of Arctic ozone loss under climate change conditions.

Cell-free plasma DNA as a novel marker of aseptic inflammation severity related to exercise overtraining.

PubMed

Fatouros, Ioannis G; Destouni, Aspasia; Margonis, Konstantinos; Jamurtas, Athanasios Z; Vrettou, Christina; Kouretas, Dimitrios; Mastorakos, George; Mitrakou, Asimina; Taxildaris, Kiriakos; Kanavakis, Emmanouel; Papassotiriou, Ioannis

2006-09-01

Circulating free plasma DNA is implicated in conditions associated with tissue injury, including exercise-induced inflammation, and thus is a potential marker for athletic overtraining. We measured free plasma DNA along with C-reactive protein (CRP), creatine kinase (CK), and uric acid (UA) in 17 recreationally trained men participating in a 12-week resistance training regimen (8 resistance multi-joint exercises selected to stress the entire musculature: bench press, squat, leg press, snatch, hang clean, dead lifts, barbell arm curls, and rowing), consisting of 4 training periods (t1, t2, t3, and t4). Plasma DNA concentrations increased markedly after t1, t2, and t3 and returned to baseline after t4. There were substantial differences between t2 and t1 and between t3 and t2 plasma DNA concentrations. CRP increased by 300% after t2 and by 400% after t3 (there was no difference between t2 and t3 CRP values) compared with baseline (t0). CK increased only after t3. UA increased after t2 and t3, with a greater increase after t3. This study demonstrates that, after chronic excessive resistance exercise, plasma DNA concentrations increase in proportion to training load, suggesting that plasma DNA may be a sensitive marker for overtraining-induced inflammation.

Highly sensitive determination of iron (III) ion based on phenanthroline probe: Surface-enhanced Raman spectroscopy methods

NASA Astrophysics Data System (ADS)

Chen, Lei; Ma, Ning; Park, Yeonju; Jin, Sila; Hwang, Hoon; Jiang, Dayu; Jung, Young Mee

2018-05-01

In this paper, we introduced Raman spectroscopy techniques that were based on the traditional Fe3 + determination method with phenanthroline as a probe. Interestingly, surface-enhanced Raman spectroscopy (SERS)-based approach exhibited excellent sensitivities to phenanthroline. Different detection mechanisms were observed for the RR and SERS techniques, in which the RR intensity increased with increasing Fe3 + concentration due to the observation of the RR effect of the phenanthroline-Fe2 + complex, whereas the SERS intensity increased with decreasing Fe3 + concentration due to the observation of the SERS effect of the uncomplexed phenanthroline. More importantly, the determination sensitivity was substantially improved in the presence of a SERS-active substrate, giving a detection limit as low as 0.001 μg/mL, which is 20 times lower than the limit of the UV-vis and RR methods. Furthermore, the proposed SERS method was free from other ions interference and can be used quality and sensitivity for the determination of the city tap water.

The effect of boron concentration on the structure and elastic properties of Ru-Ir alloys: first-principles calculations

NASA Astrophysics Data System (ADS)

Li, Xiaolong; Zhou, Zhaobo; Hu, Riming; Zhou, Xiaolong; Yu, Jie; Liu, Manmen

2018-04-01

The Phase stability, electronic structure, elastic properties and hardness of Ru-Ir alloys with different B concentration were investigated by first principles calculations. The calculated formation enthaplies and cohesive energies show that these compounds are all thermodynamically stable. Information on electronic structure indicates that they possess metallic characteristic and Ru-Ir-B alloys were composed of the Ru-B and Ir-B covalent bond. The elastic properties were calculated, which included bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio and hardness. The calculated results reveal that the plastic of Ru-Ir-B alloys increase with the increase of the content of B atoms, but the hardness of Ru-Ir-B alloys have no substantial progress with the increase of the content of B atoms. However, it is interesting that the hardness of the Ru-Ir-B compound was improved obviously as the B content was higher than 18 atoms because of a phase structure transition.

Impact of copper toxicity on stone-head cabbage (Brassica oleracea var. capitata) in hydroponics.

PubMed

Ali, Sajid; Shahbaz, Muhammad; Shahzad, Ahmad Naeem; Khan, Hafiz Azhar Ali; Anees, Moazzam; Haider, Muhammad Saleem; Fatima, Ammara

2015-01-01

Arable soils are frequently subjected to contamination with copper as the consequence of imbalanced fertilization with manure and organic fertilizers and/or extensive use of copper-containing fungicides. In the present study, the exposure of stone-head cabbage (Brassica oleracea var. capitata) to elevated Cu(2+) levels resulted in leaf chlorosis and lesser biomass yield at ≥2 µ M. Root nitrate content was not statistically affected by Cu(2+) levels, although it was substantially decreased at ≥5 µ M Cu(2+) in the shoot. The decrease in nitrate contents can be related to lower nitrate uptake rates because of growth inhibition by Cu-toxicity. Shoot sulfate content increased strongly at ≥2 µ M Cu(2+) indicating an increase in demand for sulfur under Cu stress. Furthermore, at ≥2 µM concentration, concentration of water-soluble non-protein thiol increased markedly in the roots and to a smaller level in the shoot. When exposed to elevated concentrations of Cu(2+) the improved sulfate and water-soluble non-protein thiols need further studies for the evaluation of their direct relation with the synthesis of metal-chelating compounds (i.e., phytochelatins).

Contaminants of emerging concern affect Trichoplusia ni growth and development on artificial diets and a key host plant

PubMed Central

Rothman, Jason A.; Dudley, Stacia L.; Jones, Michael B.; McFrederick, Quinn S.; Gan, Jay; Trumble, John T.

2017-01-01

Many countries are utilizing reclaimed wastewater for agriculture because drought, rising temperatures, and expanding human populations are increasing water demands. Unfortunately, wastewater often contains biologically active, pseudopersistent pharmaceuticals, even after treatment. Runoff from farms and output from wastewater treatment plants also contribute high concentrations of pharmaceuticals to the environment. This study assessed the effects of common pharmaceuticals on an agricultural pest, Trichoplusia ni (Lepidoptera: Noctuidae). Larvae were reared on artificial diets spiked with contaminants of emerging concern (CECs) at environmentally relevant concentrations. Trichoplusia ni showed increased developmental time and mortality when reared on artificial diets containing antibiotics, hormones, or a mixture of contaminants. Mortality was also increased when T. ni were reared on tomatoes grown hydroponically with the same concentrations of antibiotics. The antibiotic-treated plants translocated ciprofloxacin through their tissues to roots, shoots, and leaves. Microbial communities of T. ni changed substantially between developmental stages and when exposed to CECs in their diets. Our results suggest that use of reclaimed wastewater for irrigation of crops can affect the developmental biology and microbial communities of an insect of agricultural importance. PMID:29087336

Groundwater uranium and cancer incidence in South Carolina

PubMed Central

Wagner, Sara E.; Burch, James B.; Bottai, Matteo; Puett, Robin; Porter, Dwayne; Bolick-Aldrich, Susan; Temples, Tom; Wilkerson, Rebecca C.; Vena, John E.; Hébert, James R.

2012-01-01

Objective This ecologic study tested the hypothesis that census tracts with elevated groundwater uranium and more frequent groundwater use have increased cancer incidence. Methods Data sources included: incident total, leukemia, prostate, breast, colorectal, lung, kidney, and bladder cancers (1996–2005, SC Central Cancer Registry); demographic and groundwater use (1990 US Census); and groundwater uranium concentrations (n = 4,600, from existing federal and state databases). Kriging was used to predict average uranium concentrations within tracts. The relationship between uranium and standardized cancer incidence ratios was modeled among tracts with substantial groundwater use via linear or semiparametric regression, with and without stratification by the proportion of African Americans in each area. Results A total of 134,685 cancer cases were evaluated. Tracts with ≥50% groundwater use and uranium concentrations in the upper quartile had increased risks for colorectal, breast, kidney, prostate, and total cancer compared to referent tracts. Some of these relationships were more likely to be observed among tracts populated primarily by African Americans. Conclusion SC regions with elevated groundwater uranium and more groundwater use may have an increased incidence of certain cancers, although additional research is needed since the design precluded adjustment for race or other predictive factors at the individual level. PMID:21080052

Changes in power and force generation during coupled eccentric-concentric versus concentric muscle contraction with training and aging.

PubMed

Caserotti, Paolo; Aagaard, Per; Puggaard, Lis

2008-05-01

Age-related decline in maximal concentric muscle power is associated with frailty and functional impairments in the elderly. Compared to concentric contraction, mechanical muscle output is generally enhanced when muscles are rapidly pre-stretched (eccentric contraction), albeit less pronounced with increasing age. Exercise has been recommended to prevent loss of muscle power and function and recent guidelines indicate training program for increasing muscle power highly relevant for elderly subjects. This study examined the differences in muscle power, force and movement pattern during concentric-alone and coupled eccentric-concentric contraction and selected functional motor performances before and after 36-week multicomponent training including aerobic, strength, balance, flexibility and coordination components in elderly males. Vertical force, excursion, velocity, power and acceleration of the body center of mass were measured in two standardised vertical jumps (squatting jump, SQJ; countermovement jump, CMJ). Pre-stretch enhancement during CMJ did not improve performance [i.e., no enhanced maximal muscle power (Ppeak) and jump height (JH)] compared to concentric-alone muscle contraction (SQJ). Nevertheless, pre-stretch enhancement occurred as for similar SQJ and CMJ maximal performance, elderly people employed lower mechanical work, higher mean muscle power (Pmean), shorter concentric phase duration and shorter body center of mass displacement during CMJ. Post training, CMJ Ppeak, Pmean and JH increased in training group (P<0.05) while Ppeak and JH decreased in control group during the CMJ and SQJ (P<0.05). In conclusion, long-term training counteracted the age-related decline in muscle power and functional performance observed in the control subjects, while substantial gains in muscular performance were observed in the trained elderly.

The Distribution of Road Salt in Private Drinking Water Wells in a Southeastern New York Suburban Township.

PubMed

Kelly, Victoria R; Cunningham, Mary Ann; Curri, Neil; Findlay, Stuart E; Carroll, Sean M

2018-05-01

We used a GIS analysis of sodium and chloride concentrations in private water wells in a southeastern New York township to describe the pattern of distribution of road salt in aquifers tapped for drinking water. The primary source of road salt was sodium chloride, and sodium and chloride concentrations were significantly correlated ( = 0.80, < 0.01). Chloride concentrations in wells increased as the percentage of impervious surface cover (ISC) within a 250-m radius around wells increased ( = 0.87, < 0.01) and declined with increasing distance to the nearest road ( = 0.76, < 0.01). Wells that were located lower in elevation than the nearest road had higher concentrations of chloride than wells that were higher than the nearest road, but this occurred only when the nearest road was >30 m from the wells ( < 0.01). Chloride concentrations were not affected by well depth or adjacent road type (major or minor roads). Surface geology and hydrologic soil class had significant effects ( < 0.01) on chloride concentrations in wells, with porous surface geology types and well-drained soils having higher concentrations; these effects may be confounded by the fact that ISC was more likely to occur on these permeable surface geology and soil types. Hot and cold spot analysis revealed substantial unevenness in chloride concentrations. Results for sodium were similar to those for chloride. Overall, these results indicate that road salt contamination of groundwater is unevenly distributed and is affected by landscape factors that can be used to guide well testing and best management practices of deicing salt distribution. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The effect of dietary protein restriction on the secretory dynamics of 1 alpha-hydroxycorticosterone and urea in the dogfish, Scyliorhinus canicula: a possible role for 1 alpha-hydroxycorticosterone in sodium retention.

PubMed

Armour, K J; O'Toole, L B; Hazon, N

1993-08-01

The putative osmoregulatory role of the unique elasmobranch corticosteroid, 1 alpha-hydroxycorticosterone (1 alpha-OH-B), was investigated using dietary protein restriction as a means of limiting urea biosynthetic ability. Groups of dogfish (Scyliorhinus canicula) were adapted to either a high or a low protein diet (HPD and LPD respectively) and the secretory dynamics of urea and 1 alpha-OH-B were determined following acclimation to normal (100%), 130% and 50% sea water. In normal sea water, LPD fish showed significantly decreased blood production of urea compared with fish fed a HPD (P < 0.05), and the plasma urea concentration required to maintain iso-osmolality was achieved only by a substantial decrease in urea clearance from the plasma. Unlike HPD fish, LPD fish in 130% sea water had no apparent ability to increase plasma urea concentration. An alternative strategy adopted by these animals was the retention of high plasma concentrations of Na+ and Cl-, which increased plasma osmolality and tended to decrease osmotic water loss. Concomitant with the increased ion concentrations, plasma 1 alpha-OH-B concentration was also greatly elevated in LPD fish indicating that the steroid may be acting to minimize Na+ (and Cl-) excretion at osmoregulatory sites such as the rectal gland, kidney and gills. This and a previous study have also demonstrated that 1 alpha-OH-B concentration is elevated in 50% sea water. Decreases in plasma Na+ concentration are tolerated down to 75% sea water, whereafter Na+ is preferentially retained and further decreases in osmolality are achieved by reductions in plasma urea concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

A container for heat treating materials in microwave ovens

DOEpatents

Holcombe, C.E.; Dykes, N.L.; Kimrey, H.D. Jr.; Mills, J.E.

1988-01-26

The efficiency of a microwave oven of a conventional two-source configuration and energy level is increased by providing the oven with a container for housing a refractory material to be treated. The container is formed to top and bottom walls transparent to microwaves while the sidewalls, in a circular configuration, are formed of a nonmetallic material opaque to microwave radiation for reflecting the radiation penetrating the top and bottom walls radially inwardly into the center of the container wherein a casket of heat-insulating material is provided for housing the material to be heat treated. The reflection of the microwave radiation from the sidewalls increases the concentration of the microwaves upon the material being heat treated while the concentration of the microwaves upon the material being heat treated while the casket retains the heat to permit the heating of the material to a substantially higher temperature than achievable in the oven without the container.

Centennial record of anthropogenic impacts in Galveston Bay: Evidence from trace metals (Hg, Pb, Ni, Zn) and lignin oxidation products.

PubMed

Al Mukaimi, Mohammad E; Kaiser, Karl; Williams, Joshua R; Dellapenna, Timothy M; Louchouarn, Patrick; Santschi, Peter H

2018-06-01

During the 20th century the impacts of industrialization and urbanization in Galveston Bay resulted in significant shifts in trace metals (Hg, Pb, Ni, Zn) and vascular plant biomarkers (lignin phenols) recorded within the surface sediments and sediment cores profile. A total of 22 sediment cores were collected in Galveston Bay in order to reconstruct the historical input of Hg, Pb, Ni, Zn and terrestrial organic matter. Total Hg (T-Hg) concentration ranged between 6 and 162 ng g -1 in surface sediments, and showed decreasing concentrations southward from the Houston Ship Channel (HSC) toward the open estuary. Core profiles of T-Hg and trace metals (Ni, Zn) showed substantial inputs starting in 1905, with peak concentrations between 1960 and 1970's, and decreasing thereafter with exception to Pb, which peaked around 1930-1940s. Stable carbon isotopes and lignin phenols showed an increasing input of terrestrial organic matter driven by urban development within the watershed in the early 1940s. Both the enrichment factor and the geoaccumulation index (I geo ) for T-Hg as a measure of the effectiveness of environmental management practices showed substantial improvements since the 1970s. The natural recovery rate in Galveston Bay since the peak input of T-Hg was non-linear and displayed a slow recovery during the twenty-first century. Copyright © 2018 Elsevier Ltd. All rights reserved.

Tight coupling of particle size and composition in atmospheric cloud droplet activation

NASA Astrophysics Data System (ADS)

Topping, D.; McFiggans, G.

2011-09-01

The substantial uncertainty in the indirect effect on radiative forcing in large part arises from the influences of atmospheric aerosol particles on (i) the brightness of clouds, exerting significant shortwave cooling with no appreciable compensation in the longwave, and on (ii) their ability to precipitate, with implications for cloud cover and lifetime. Predicting the ambient conditions at which aerosol particles may become cloud droplets is largely reliant on an equilibrium relationship derived in 1936. However, the theoretical basis of the relationship restricts its application to particles solely comprising involatile compounds and water, whereas a substantial fraction of particles in the real atmosphere will contain potentially thousands of semi-volatile organic compounds in addition to containing semi-volatile inorganic components such as ammonium nitrate. We show that equilibration of atmospherically reasonable concentrations of organic compounds with a growing particle as the ambient humidity increases has larger implications on cloud droplet formation than any other equilibrium compositional dependence, owing to inextricable linkage between the aerosol composition and a particles size under ambient conditions. Whilst previous attempts to account for co-condensation of gases other than water vapour have been restricted to one inorganic condensate, our method demonstrates that accounting for the co-condensation of any number of organic compounds substantially decreases the saturation ratio of water vapour required for droplet activation. This effect is far greater than any other compositional dependence; moreso even than the unphysical effect of surface tension reduction in aqueous organic mixtures, ignoring differences in bulk and surface surfactant concentrations.

Response of potatoes to nitrogen concentrations differ with nitrogen forms

NASA Technical Reports Server (NTRS)

Cao, W.; Tibbitts, T. W.

1998-01-01

Two separate experiments were conducted to investigate plant growth and mineral composition of potatoes (Solanum tuberosum L.) at varied solution concentrations of nitrate (NO3-) and ammonium (NH4+). Each experiment evaluated five nitrogen (N) concentrations of 0.5, 2, 4, 8, and 12 mM, which were maintained with a non-recirculating nutrient film system in controlled environment. Plants were harvested on day 42 with NO3-; and day 35 with NH4+ after transplanting of tissue culture plantlets, and growth measurements were taken as leaf area, tuber number, and dry weights of different parts. With NO3-, plant growth was greatest and similar at 2, 4, and 8 mM of N whereas with NH4+, plant growth was best only at 2 and 4 mM of N. At 12 mM of N, plants exhibited interveinal ammonium toxicity with NH4+ nutrition, but healthy growth appearance with NO3- nutrition. With either N form, total N concentrations in tissues tended to increase with increased N concentrations, and tissue phosphorus (P) concentrations were reduced at 0.5 and 2 mM of N. Tissue concentrations of calcium (Ca), magnesium (Mg), and sulfur (S) changed only slightly at particular N concentrations, yet changed substantially with different N forms. The data indicate that the optimal ranges of N concentrations in both solution and tissues are wider and higher with NO3- than with NH4+ nutrition, and thus a careful control of NH4+ concentrations is necessary to minimize possible ammonium toxicity to potato plants.

Contribution of forest fires to concentrations of particulate matter in Singapore

NASA Astrophysics Data System (ADS)

Spracklen, D. V.; Reddington, C.; Yoshioka, M.; Arnold, S.; Balasubramanian, R.

2013-12-01

Singapore is regularly exposed to substantial levels of transboundary air pollution arising from uncontrolled forest and peat fires from specific regions within Southeast Asia. This air pollution has detrimental impacts on the lives of Singapore residents and on sensitive ecosystems. In June 2013, forest fires resulted in concentrations of particulate matter greatly exceeding levels recommended for human health, causing substantial public concern. We apply two different methods to quantify the impact of forest fires on the concentrations of particulate matter with diameter less than 2.5 micrometres (PM2.5) in Singapore. Firstly, we use a global aerosol model (GLOMAP) in combination with fire emissions from GFED3 to simulate PM2.5 concentrations over the period 1998-2009. We evaluate simulated PM2.5 concentrations against long-term observations from Singapore. To identify the contributions of fires from different source regions to PM2.5 concentrations we run multiple simulations with and without fire emissions from specific regions across Southeast Asia. Secondly, we apply an atmospheric back trajectory model in combination with the GFED3 fire emissions to calculate exposure of air masses arriving in Singapore to fire emissions. Both methods use meteorology from the European Centre for Medium Range Weather Forecasts and are consistent with the large-scale atmospheric flow from the assimilated observations. We find that both methods give consistent results, with forest fires increasing PM2.5 concentrations in Singapore predominately during April to October. Forest and peat fires in Sumatra and Kalimantan cause the greatest degradation of air quality in Singapore. The contribution of fires to PM2.5 concentrations in Singapore exhibits strong interannual variability. During years with a strong contribution from fires, our simulations show that the prevention of fires in southern Sumatra would reduce regional PM2.5 concentrations around Singapore by more than a factor of two, potentially allowing Singapore to meet World Health Organisation guidelines for annual mean concentrations of PM2.5. Acting to reduce forest and peat fires in southern Sumatra, in particular provinces of Lampung, South Sumatra and Jambi, and southern Kalimantan would likely have the greatest environmental benefits to Singapore and surrounding regions.

Export of Nitrogen From the Yukon River Basin to the Bering Sea

NASA Astrophysics Data System (ADS)

Dornblaser, M. M.; Striegl, R. G.

2005-12-01

The US Geological Survey measured nitrogen export from the 831,400 km2 Yukon River basin during 2001-04 as part of a five year water quality study of the Yukon River and its major tributaries. Concentrations of NO2+NO3, NH4+DON, and particulate N were measured ~6 times annually during open water and once under ice cover at three locations on the Yukon River, and on the Porcupine and Tanana Rivers. Concentration and continuous flow data were used to generate daily and annual loads of N species. NH4 concentration was generally negligible when compared to DON concentration, allowing for comparison of the relative importance of DIN vs. DON export at various watershed scales. NO2 concentration was also small compared to NO3. At Pilot Station, the last site on the Yukon before it flows into the Yukon Delta and the Bering Sea, DIN, DON, and particulate N loads averaged 19.3 × 106 kg/yr, 52.6 × 106 kg/yr, and 39.1 × 106 kg/yr, respectively. Normalized for the watershed area at Pilot Station, corresponding N yields were 1.65, 4.52, and 3.35 mmol/m2/yr. DIN yield for the Yukon at Pilot Station is substantially less than the NO3 flux reported for tropical/temperate rivers such as the Amazon, the Yangtze, and the Mississippi. DIN yield in the upper Yukon River basin is similar to that of the Mackenzie and other arctic rivers, but increases substantially downstream. This is likely due to development around Fairbanks in the Tanana River basin. When compared to other headwater basins in the upper Yukon, the Tanana basin yields about four times more DIN and two times more particulate N, while DON yields are only slightly elevated.

Lean burn natural gas fueled S.I. engine and exhaust emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varde, K.S.; Patro, N.; Drouillard, K.

1995-12-31

An experimental study was undertaken to study exhaust emission from a lean-burn natural gas spark ignition engine. The possibility that such an engine may help to reduce exhaust emissions substantially by taking advantage of natural gas fuel properties, such as its antiknock properties and extended lean flammability limit compared to gasoline, was the main motivation behind the investigation. A four cylinder, automotive type spark ignition engine was used in the investigation. The engine was converted to operate on natural gas by replacing its fuel system with a gaseous carburetion system. A 3-way metal metrix catalytic converter was used in themore » engine exhaust system to reduce emission levels. The engine operated satisfactorily at an equivalence ratio as lean as 0.6, at all speeds and loads. As a result NOx emissions were significantly reduced. However, hydrocarbon emissions were high, particularly at very lean conditions and light loads. Most of these hydrocarbons were made up of methane with small concentrations of ethane and propane. Coefficient of variations in hydrocarbons were generally high at very lean operating conditions and light loads, but decreased with increasing equivalence ratio and engine speed. Methane concentrations in the engine exhaust decreased with increasing load and equivalence ratio. At lean air-to-fuel ratios and light loads oxidation of methane in the catalyst was substantially limited and no NOx reduction was achieved. In addition, the proportion of nitric oxide in oxides of nitrogen increased with increasing amount of NOx in the engine exhaust. A major problem encountered in the study was the inability of the fuel system to maintain near constant air-to-fuel ratios at steady operating conditions.« less

In-Lake Processes Offset Increased Terrestrial Inputs of Dissolved Organic Carbon and Color to Lakes

PubMed Central

Köhler, Stephan J.; Kothawala, Dolly; Futter, Martyn N.; Liungman, Olof; Tranvik, Lars

2013-01-01

Increased color in surface waters, or browning, can alter lake ecological function, lake thermal stratification and pose difficulties for drinking water treatment. Mechanisms suggested to cause browning include increased dissolved organic carbon (DOC) and iron concentrations, as well as a shift to more colored DOC. While browning of surface waters is widespread and well documented, little is known about why some lakes resist it. Here, we present a comprehensive study of Mälaren, the third largest lake in Sweden. In Mälaren, the vast majority of water and DOC enters a western lake basin, and after approximately 2.8 years, drains from an eastern basin. Despite 40 years of increased terrestrial inputs of colored substances to western lake basins, the eastern basin has resisted browning over this time period. Here we find the half-life of iron was far shorter (0.6 years) than colored organic matter (A420 ; 1.7 years) and DOC as a whole (6.1 years). We found changes in filtered iron concentrations relate strongly to the observed loss of color in the western basins. In addition, we observed a substantial shift from colored DOC of terrestrial origin, to less colored autochthonous sources, with a substantial decrease in aromaticity (-17%) across the lake. We suggest that rapid losses of iron and colored DOC caused the limited browning observed in eastern lake basins. Across a wider dataset of 69 Swedish lakes, we observed greatest browning in acidic lakes with shorter retention times (< 1.5 years). These findings suggest that water residence time, along with iron, pH and colored DOC may be of central importance when modeling and projecting changes in brownification on broader spatial scales. PMID:23976946

Predictive value of early changes in triglycerides and weight for longer-term changes in metabolic measures during olanzapine, ziprasidone or aripiprazole treatment for schizophrenia and schizoaffective disorder post hoc analyses of 3 randomized, controlled clinical trials.

PubMed

Hoffmann, Vicki P; Case, Michael; Stauffer, Virginia L; Jacobson, Jennie G; Conley, Robert R

2010-12-01

The objective of this study was to determine if early changes in triglycerides and weight may be useful in predicting longer-term changes in weight and other metabolic parameters. Data were from three 24- to 28-week randomized, controlled studies comparing olanzapine to ziprasidone or aripiprazole for treatment of schizophrenia. Analyses were restricted to completers with fasting laboratory data at all protocol specified time points. Analyses were primarily descriptive and included mean changes and categorical outcomes. In all treatment groups, participants who did not experience a 20 mg/dL or greater increase in triglycerides at early time points were unlikely to experience a change of 50 mg/dL or more in triglycerides after 6 months. Negative predictive values were 83% to 95%. However, early change in triglycerides was not useful for predicting later change in glucose, cholesterol, or weight. Similarly, early weight change gave robust negative predictive values for longer-term weight change (≥10 kg), but not for change in glucose or cholesterol. Lack of early elevation in triglyceride concentrations was predictive of later lack of substantial increase in triglycerides in olanzapine-, ziprasidone-, and aripiprazole-treated participants. Lack of early elevation in weight was predictive of later lack of substantial increase in weight in all 3 treatment groups. Early monitoring of triglyceride concentrations and weight may help clinicians assess risk that individuals will experience significant increase in triglycerides or weight gain, allowing assessments of potential risks and benefits earlier in treatment. Clinical monitoring is advised throughout treatment for all patients.

Field-induced structural control of COx molecules adsorbed on graphene

NASA Astrophysics Data System (ADS)

Matsubara, Manaho; Okada, Susumu

2018-05-01

Using the density functional theory combined with both the van der Waals correction and the effective screening medium method, we investigate the energetics and electronic structures of CO and CO2 molecules adsorbed on graphene surfaces in the field-effect-transistor structure with respect to the external electric field by the excess electrons/holes. The binding energies of CO and CO2 molecules to graphene monotonically increase with increasing hole and electron concentrations. The increase occurs regardless of the molecular conformations to graphene and the counter electrode, indicating that the carrier injection substantially enhances the molecular adsorption on graphene. Injected carriers also modulate the stable molecular conformation, which is metastable in the absence of an electric field.

Decreasing the NO3 and increasing the vitamin C contents in spinach by a nitrogen deprivation method.

PubMed

Mozafar, A

1996-02-01

Excessive use of nitrogen fertilizers is known to increase the NO3 and reduce the vitamin C contents in fruits and vegetables. We investigated the concentration of these compounds in spinach leaves when plants were transferred to nitrogen-free media prior to their harvest. It was noted that a pre-harvest transfer of spinach to N-free media reduces the NO3 and increases the vitamin C content of the leaves by a substantial amount in a 2-3 day period. It is suggested that this technique may be suited to produce spinach or other leafy vegetables with low NO3 and high vitamin C contents under commercial hydroponic conditions.

A field study on chemistry, S(IV) oxidation rates and vertical transport during fog conditions

NASA Astrophysics Data System (ADS)

Joos, F.; Baltensperger, U.

An extensive fog study was carried out in the central plateu of Switzerland. Ninety-seven fog samples were collected along with aerosol filter and cascade impactor samples, and measurements of O 3, SO 2, NO, NO x, PAN, temperature, and wind speed and direction. Maximum levels in fogwater were 4.3, 4.4., 0.033, 1.7, 0.5, 0.024 and 9.2 mmol ℓ -1 for Cl -, NO 3-, NO 2-, SO 42-, S(IV), oxalate and NH 4+, respectively. pH varied between 2.9 and 7.1. Sixteen additional elements were determined in the fog samples by ICP. The sum of the concentrations of SO 42- and S(IV) agreed very with the total sulfur concentration as determined by ICP. A substantial excess of S(IV) (up to 0.2 mmol ℓ -1) compared to Henry and acid-base equilibrium calculations was found, which can probably be attributed to complex formations with aldehydes. S(IV) oxidation rates of up to 650 nmol ℓ -1 s -1 with ozone and of up to 100 nmol ℓ -1 s -1 with NO 2 were calculated. S(IV) oxidation due to PAN, NO 2- and Fe(III) was of minor importance. A substantial fraction of the major ions was present in the intersitial aerosol (aerosol particles < 4 μm) even during fog conditions. High correlations were found for NH 4+, NO 32-. From their ratios in the fog water and the aerosol (< 4 μm) it could be concluded that at least 40% of NO 3- and 20% of NH 4+ in fog water was due to gas phase scavenging. Increasing concentrations in fog water were found during fog dissipation. Concentrations decreased with increasing height. A vertical transport model including turbulent diffusion and droplet sedimentation is introduced, which matches the experimental data of this vertical profile.

Critical review of mercury fates and contamination in the Arctic tundra ecosystem.

PubMed

Poissant, Laurier; Zhang, Hong H; Canário, João; Constant, Philippe

2008-08-01

Mercury (Hg) contamination in tundra region has raised substantial concerns, especially since the first report of atmospheric mercury depletion events (AMDEs) in the Polar Regions. During the past decade, steady progress has been made in the research of Hg cycling in the Polar Regions. This has generated a unique opportunity to survey the whole Arctic in respect to Hg issue and to find out new discoveries. However, there are still considerable knowledge gaps and debates on the fate of Hg in the Arctic and Antarctica, especially regarding the importance and significance of AMDEs vs. net Hg loadings and other processes that burden Hg in the Arctic. Some studies argued that climate warming since the last century has exerted profound effects on the limnology of High Arctic lakes, including substantial increases in autochthonous primary productivity which increased in sedimentary Hg, whereas some others pointed out the importance of the formation and postdeposition crystallographic history of the snow and ice crystals in determining the fate and concentration of mercury in the cryosphere in addition to AMDEs. Is mercury re-emitted back to the atmosphere after AMDEs? Is Hg methylation effective in the Arctic tundra? Where the sources of MeHg are? What is its fate? Is this stimulated by human made? This paper presents a critical review about the fate of Hg in the Arctic tundra, such as pathways and process of Hg delivery into the Arctic ecosystem; Hg concentrations in freshwater and marine ecosystems; Hg concentrations in terrestrial biota; trophic transfer of Hg and bioaccumulation of Hg through food chain. This critical review of mercury fates and contamination in the Arctic tundra ecosystem is assessing the impacts and potential risks of Hg contamination on the health of Arctic people and the global northern environment by highlighting and "perspectiving" the various mercury processes and concentrations found in the Arctic tundra.

Effects of advanced treatment of municipal wastewater on the White River near Indianapolis, Indiana; trends in water quality, 1978-86

USGS Publications Warehouse

Crawford, Charles G.; Wangsness, David J.

1993-01-01

The City of Indianapolis has constructed state-of-the-art advanced municipal wastewater-treatment systems to enlarge and upgrade the existing secondary-treatment processes at its Belmont and Southport treatment plants. These new advanced-wastewater-treatment plants became operational in 1983. A nonparametric statistical procedure--a modified form of the Wilcoxon-Mann-Whitney rank-sum test--was used to test for trends in time-series water-quality data from four sites on the White River and from the Belmont and Southport wastewater-treatment plants. Time-series data representative of pre-advanced- (1978-1980) and post-advanced- (1983--86) wastewater-treatment conditions were tested for trends, and the results indicate substantial changes in water quality of treated effluent and of the White River downstream from Indianapolis after implementation of advanced wastewater treatment. Water quality from 1981 through 1982 was highly variable due to plant construction. Therefore, this time period was excluded from the analysis. Water quality at sample sites located upstream from the wastewater-treatment plants was relatively constant during the period of study (1978-86). Analysis of data from the two plants and downstream from the plants indicates statistically significant decreasing trends in effluent concentrations of total ammonia, 5-day biochemical-oxygen demand, fecal-coliform bacteria, total phosphate, and total solids at all sites where sufficient data were available for testing. Because of in-plant nitrification, increases in nitrate concentration were statistically significant in the two plants and in the White River. The decrease in ammonia concentrations and 5-day biochemical-oxygen demand in the White River resulted in a statistically significant increasing trend in dissolved-oxygen concentration in the river because of reduced oxygen demand for nitrification and biochemical oxidation processes. Following implementation of advanced wastewater treatment, the number of river-quality samples that failed to meet the water-quality standards for ammonia and dissolved oxygen that apply to the White River decreased substantially.

Halogenated volatile organic compounds in chlorine-bleach-containing household products and implications for their use

NASA Astrophysics Data System (ADS)

Odabasi, Mustafa; Elbir, Tolga; Dumanoglu, Yetkin; Sofuoglu, Sait C.

2014-08-01

It was recently shown that substantial amounts of halogenated volatile organic compounds (VOCs) are formed in chlorine-bleach-containing household products as a result of reactions of sodium hypochlorite with organic product components. Use of these household products results in elevated indoor air halogenated VOC concentrations. Halogenated VOCs in several chlorine-bleach-containing household products (plain, n = 9; fragranced, n = 4; and surfactant-added, n = 29) from Europe and North America were measured in the present study. Chloroform and carbon tetrachloride were the dominating compounds having average concentrations of 9.5 ± 29.0 (average ± SD) and 23.2 ± 44.3 (average ± SD) mg L-1, respectively. Halogenated VOC concentrations were the lowest in plain bleach, slightly higher in fragranced products and the highest in the surfactant-added products. Investigation of the relationship between the halogenated VOCs and several product ingredients indicated that chlorinated VOC formation is closely related to product composition. Indoor air concentrations from the household use of bleach products (i.e., bathroom, kitchen, and hallway cleaning) were estimated for the two dominating VOCs (chloroform and carbon tetrachloride). Estimated indoor concentrations ranged between 0.5 and 1030 (34 ± 123, average ± SD) μg m-3 and 0.3-1124 (82 ± 194, average ± SD) μg m-3 for chloroform and carbon tetrachloride, respectively, indicating substantial increases compared to background. Results indicated that indoor air concentrations from surfactant-added products were significantly higher (p < 0.01) than other categories. The highest concentrations were from the use of surfactant-added bleach products for bathroom cleaning (92 ± 228 and 224 ± 334 μg m-3, average ± SD for chloroform and carbon tetrachloride, respectively). Associated carcinogenic risks from the use of these products were also estimated. The risk levels may reach to considerably high levels for a significant portion of the population especially for those steadily using the surfactant-added bleach products. Based on the results of the present study, it could be recommended that if possible the use of chlorine bleach containing household products should be avoided. If they are to be used, plain products should be preferred since the chlorinated VOC content increase with the number and amount of additives.

Ultra-capacitor flexible films with tailored dielectric constants using electric field assisted assembly of nanoparticles.

PubMed

Batra, Saurabh; Cakmak, Miko

2015-12-28

In this study, the chaining and preferential alignment of barium titanate nanoparticles (100 nm) through the thickness direction of a polymer matrix in the presence of an electric field is shown. Application of an AC electric field in a well-dispersed solution leads to the formation of chains of nanoparticles in discrete rows oriented with their primary axis in the E-field direction due to dielectrophoresis. The change in the orientation of these chains was quantified through statistical analysis of SEM images and was found to be dependent on E-field, frequency and viscosity. When a DC field is applied a distinct layer consisting of dense particles was observed with micro-computed tomography. These studies show that the increase in DC voltage leads to increase in the thickness of the particle rich layer along with the packing density also increasing. Increasing the mutual interactions between particles due to the formation of particle chains in the "Z"-direction decreases the critical percolation concentration above which substantial enhancement of properties occurs. This manufacturing method therefore shows promise to lower the cost of the products for a range of applications including capacitors by either enhancing the dielectric properties for a given concentration or reduces the concentration of nanoparticles needed for a given property.

Characterization of erythrosine B binding to bovine serum albumin and bilirubin displacement.

PubMed

Mathavan, Vinodaran M K; Boh, Boon Kim; Tayyab, Saad

2009-08-01

The interaction of crythrosine B (ErB), a commonly used dye for coloring foods and drinks, with bovine scrum albumin (BSA) was investigated both in the absence and presence of bilirubin (BR) using absorption and absorption difference spectroscopy. ErB binding to BSA was reflected from a significant red shift of 11 nm in the absorption maximum of ErB (527 nm) with the change in absorbance at lamdamax. Analysis of absorption difference spectroscopic titration results of BSA with increasing concentrations of ErB3 using Benesi-Hildebrand equation gave the association constant, K as 6.9 x 10(4) M(-1). BR displacing action of ErB was revealed by a significant blue shift in the absorption maximum, accompanied by a decrease in absorbance difference at lamdamax in the difference spectrum of BR-BSA complex upon addition of increasing concentrations of ErB. This was further substantiated by fluorescence spectroscopy, as addition of increasing concentrations of ErB to BR-BSA complex caused a significant decrease in fluoresccnce at 510 nm. The results suggest that ErB binds to a site in the vicinity of BR binding site on BSA. Therefore, intake of ErB may increase the risk of hyperbilirubinemia in the healthy subjects.

Contamination of the O2 soil horizon by zinc smelting and its effect on woodlouse survival

USGS Publications Warehouse

Beyer, W.N.; Miller, G.W.; Cromartie, E.J.

1984-01-01

Samples of litter from the 02 horizon of Dekalb soil (loamyskeletal, mixed, mesic Typic Dystrochrept) were collected from 18 ridgetop sites on a transect that ran by two Zn smelters in Palmerton, Pa. Metal concentrations increased by regular gradations from a minimum at a site 105 km west of the smelters (67 mg/kg Zn, 0.85 mg/kg Cd, 150 mg/kg Pb, 11 mg/kg Cu) to a maximum 1.2 km east of the smelters (35,000 mg/kg Zn, 1300 mg/kg Cd, 3200 mg/kg Pb, 280 mg/kg Cu), and then decreased until they reached an eastern minimum at the easternmost site, 19 km from the smelters. An increase in the P concentrations near the smelters showed that the emissions were disrupting nutrient flow through the ecosystem. An increase in the pH near the smelters was attributed to the high concentrations of Zn. The log of the distance of the sites from the smelters was significantly correlated (r = - 0.80, p < 0.05) with the mortality of woodlice (Porcellio scaber Latreille} fed samples of the litter during an 8-week test. There was substantial mortality of woodlice observed even in the 02 litter collected 19 km east of the smelters. Zinc, cadmium, lead, copper, and sulfur were experimentally added, alone or in combination, to 02 litter collected far from any known source of metal emissions. The highest concentration of Zn added (20,000 mg/kg) was toxic enough to account for the mortality observed in the earlier test. A lower concentration of Zn (5000 mg/kg) as well as the concentration of Cd (500 mg/kg) tested also significantly (p < 0.05) increased the mortality of woodlice.

Impact of humic acids on the colonic microbiome in healthy volunteers.

PubMed

Swidsinski, Alexander; Dörffel, Yvonne; Loening-Baucke, Vera; Gille, Christoph; Reißhauer, Anne; Göktas, Onder; Krüger, Monika; Neuhaus, Jürgen; Schrödl, Wieland

2017-02-07

To test the effects of humic acids on innate microbial communities of the colon. We followed the effects of oral supplementation with humic acids (Activomin ® ) on concentrations and composition of colonic microbiome in 14 healthy volunteers for 45 d. 3 × 800 mg Activomin ® were taken orally for 10 d followed by 3 × 400 mg for 35 d. Colonic microbiota were investigated using multicolor fluorescence in situ hybridization (FISH) of Carnoy fixated and paraffin embedded stool cylinders. Two stool samples were collected a week prior to therapy and one stool sample on days 10, 31 and 45. Forty-one FISH probes representing different bacterial groups were used. The sum concentration of colonic microbiota increased from 20% at day 10 to 30% by day 31 and remained stable until day 45 (32%) of humic acid supplementation ( P < 0.001). The increase in the concentrations in each person was due to growth of preexisting groups. The individual microbial profile of the patients remained unchanged. Similarly, the bacterial diversity remained stable. Concentrations of 24 of the 35 substantial groups increased from 20% to 96%. Two bacterial groups detected with Bac303 ( Bacteroides ) and Myc657 (mycolic acid-containing Actinomycetes ) FISH probes decreased ( P > 0.05). The others remained unaffected. Bacterial groups with initially marginal concentrations (< 0.1 × 10 9 /mL) demonstrated no response to humic acids. The concentrations of pioneer groups of Bifidobacteriaceae , Enterobacteriaceae and Clostridium difficile increased but the observed differences were statistically not significant. Humic acids have a profound effect on healthy colonic microbiome and may be potentially interesting substances for the development of drugs that control the innate colonic microbiome.

Impact of humic acids on the colonic microbiome in healthy volunteers

PubMed Central

Swidsinski, Alexander; Dörffel, Yvonne; Loening-Baucke, Vera; Gille, Christoph; Reißhauer, Anne; Göktas, Onder; Krüger, Monika; Neuhaus, Jürgen; Schrödl, Wieland

2017-01-01

AIM To test the effects of humic acids on innate microbial communities of the colon. METHODS We followed the effects of oral supplementation with humic acids (Activomin®) on concentrations and composition of colonic microbiome in 14 healthy volunteers for 45 d. 3 × 800 mg Activomin® were taken orally for 10 d followed by 3 × 400 mg for 35 d. Colonic microbiota were investigated using multicolor fluorescence in situ hybridization (FISH) of Carnoy fixated and paraffin embedded stool cylinders. Two stool samples were collected a week prior to therapy and one stool sample on days 10, 31 and 45. Forty-one FISH probes representing different bacterial groups were used. RESULTS The sum concentration of colonic microbiota increased from 20% at day 10 to 30% by day 31 and remained stable until day 45 (32%) of humic acid supplementation (P < 0.001). The increase in the concentrations in each person was due to growth of preexisting groups. The individual microbial profile of the patients remained unchanged. Similarly, the bacterial diversity remained stable. Concentrations of 24 of the 35 substantial groups increased from 20% to 96%. Two bacterial groups detected with Bac303 (Bacteroides) and Myc657 (mycolic acid-containing Actinomycetes) FISH probes decreased (P > 0.05). The others remained unaffected. Bacterial groups with initially marginal concentrations (< 0.1 × 109/mL) demonstrated no response to humic acids. The concentrations of pioneer groups of Bifidobacteriaceae, Enterobacteriaceae and Clostridium difficile increased but the observed differences were statistically not significant. CONCLUSION Humic acids have a profound effect on healthy colonic microbiome and may be potentially interesting substances for the development of drugs that control the innate colonic microbiome. PMID:28223733

Variation in wood nutrients along a tropical soil fertility gradient.

PubMed

Heineman, Katherine D; Turner, Benjamin L; Dalling, James W

2016-07-01

Wood contains the majority of the nutrients in tropical trees, yet controls over wood nutrient concentrations and their function are poorly understood. We measured wood nutrient concentrations in 106 tree species in 10 forest plots spanning a regional fertility gradient in Panama. For a subset of species, we quantified foliar nutrients and wood density to test whether wood nutrients scale with foliar nutrients at the species level, or wood nutrient storage increases with wood density as predicted by the wood economics spectrum. Wood nutrient concentrations varied enormously among species from fourfold in nitrogen (N) to > 30-fold in calcium (Ca), potassium (K), magnesium (Mg) and phosphorus (P). Community-weighted mean wood nutrient concentrations correlated positively with soil Ca, K, Mg and P concentrations. Wood nutrients scaled positively with leaf nutrients, supporting the hypothesis that nutrient allocation is conserved across plant organs. Wood P was most sensitive to variation in soil nutrient availability, and significant radial declines in wood P indicated that tropical trees retranslocate P as sapwood transitions to heartwood. Wood P decreased with increasing wood density, suggesting that low wood P and dense wood are traits associated with tree species persistence on low fertility soils. Substantial variation among species and communities in wood nutrient concentrations suggests that allocation of nutrients to wood, especially P, influences species distributions and nutrient dynamics in tropical forests. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Identification of specific sources of airborne particles emitted from within a complex industrial (steelworks) site

NASA Astrophysics Data System (ADS)

Beddows, D. C. S.; Harrison, Roy M.

2018-06-01

A case study is provided of the development and application of methods to identify and quantify specific sources of emissions from within a large complex industrial site. Methods include directional analysis of concentrations, chemical source tracers and correlations with gaseous emissions. Extensive measurements of PM10, PM2.5, trace gases, particulate elements and single particle mass spectra were made at sites around the Port Talbot steelworks in 2012. By using wind direction data in conjunction with real-time or hourly-average pollutant concentration measurements, it has been possible to locate areas within the steelworks associated with enhanced pollutant emissions. Directional analysis highlights the Slag Handling area of the works as the most substantial source of elevated PM10 concentrations during the measurement period. Chemical analyses of air sampled from relevant wind directions is consistent with the anticipated composition of slags, as are single particle mass spectra. Elevated concentrations of PM10 are related to inverse distance from the Slag Handling area, and concentrations increase with increased wind speed, consistent with a wind-driven resuspension source. There also appears to be a lesser source associated with Sinter Plant emissions affecting PM10 concentrations at the Fire Station monitoring site. The results are compared with a ME2 study using some of the same data, and shown to give a clearer view of the location and characteristics of emission sources, including fugitive dusts.

Rapid Shifts in Oxygen and Hydrogen Isotopes, and Chemical Components in Pore Waters During mid-Oligocene in Sediments from IODP 351drilling

NASA Astrophysics Data System (ADS)

Zhang, Z.

2017-12-01

A total of 65 pore water samples were obtained from a sediment sequence in the Amami-Sankaku Basin during the IODP 351 Expedition, which consists of a 160 m thick section of terrestrial origin and underlying 1.3 km thick volcaniclastic section sampled at site U1438. Downcore variations of chemical compositions are characterized by increasing salinity/pH, increasing concentrations of Cl and Ca, and decreasing concentrations of Mg, K and Na, as well as decreasing d18O and dD. The rapid changes in those chemical components and isotopic composition occurred deeper than the lithology boundary between Unit III and Unit II, most likely as a result of substantial difference in extent of alteration above and below this boundary. The strong alterations of volcanicalstic minerals below the boundary not only result in diminishment of K, Mg, Si, and Mn, and an increase of Ca and Cl, but also depleted d18O in pore water. However, hydrogen fractionation factors between pore water and secondary minerals are less 1, and depleted dD values in pore water most likely reflect the signal of paleo-seawater. As a result, samples below the boundary are all plotted on the left side of the meteorite water line (MWL) on the dD vs. d18O plot. Above the boundary, they are placed to the right side of MWL due to substantially weakened alteration, reflecting an evolving trend in sediment setting from the predominance of alterated volcaniclasts to terrestrial pelagic sediments.

Determination of ethane, pentane and isoprene in exhaled air--effects of breath-holding, flow rate and purified air.

PubMed

Lärstad, M A E; Torén, K; Bake, B; Olin, A-C

2007-01-01

Exhaled ethane, pentane and isoprene have been proposed as biomarkers of oxidative stress. The objectives were to explore whether ethane, pentane and isoprene are produced within the airways and to explore the effect of different sampling parameters on analyte concentrations. The flow dependency of the analyte concentrations, the concentrations in dead-space and alveolar air after breath-holding and the influence of inhaling purified air on analyte concentrations were investigated. The analytical method involved thermal desorption from sorbent tubes and gas chromatography. The studied group comprised 13 subjects with clinically stable asthma and 14 healthy controls. Ethane concentrations decreased slightly, but significantly, at higher flow rates in subjects with asthma (P = 0.0063) but not in healthy controls. Pentane levels were increased at higher flow rates both in healthy and asthmatic subjects (P = 0.022 and 0.0063 respectively). Isoprene levels were increased at higher flow rates, but only significantly in healthy subjects (P = 0.0034). After breath-holding, no significant changes in ethane levels were observed. Pentane and isoprene levels increased significantly after 20 s of breath-holding. Inhalation of purified air before exhalation resulted in a substantial decrease in ethane levels, a moderate decrease in pentane levels and an increase in isoprene levels. The major fractions of exhaled ethane, pentane and isoprene seem to be of systemic origin. There was, however, a tendency for ethane to be flow rate dependent in asthmatic subjects, although to a very limited extent, suggesting that small amounts of ethane may be formed in the airways.

Towards bridging the gap between acid-base transporters and neuronal excitability modulation

PubMed Central

Liu, Ying; Chen, Li-Ming

2014-01-01

pH homeostasis is a fundamental regulator of the function of the central nervous system. Dysfunction of acid-base transporters often results in disturbance of neuronal excitability. In a latest issue of Journal of Neuroscience, Jones et al. report that increasing intracellular bicarbonate concentration substantially stimulates the excitability of pyramidal neurons from mouse hippocampus by inhibiting KCNQ potassium channel. The finding shed important new light in understanding the molecular mechanism underlying the regulation of neuronal excitability by acid-base transporters. PMID:25755844

Space charge induced surface stresses: implications in ceria and other ionic solids.

PubMed

Sheldon, Brian W; Shenoy, Vivek B

2011-05-27

Volume changes associated with point defects in space charge layers can produce strains that substantially alter thermodynamic equilibrium near surfaces in ionic solids. For example, near-surface compressive stresses exceeding -10 GPa are predicted for ceria. The magnitude of this effect is consistent with anomalous lattice parameter increases that occur in ceria nanoparticles. These stresses should significantly alter defect concentrations and key transport properties in a wide range of materials (e.g., ceria electrolytes in fuel cells). © 2011 American Physical Society

Carbonate deposition on tail feathers of ruddy ducks using evaporation ponds

USGS Publications Warehouse

Euliss, N.H.; Jarvis, R.L.; Gilmer, D.S.

1989-01-01

Substantial carbonate deposits were observed on rectrices of Ruddy Ducks (Oxyura jamaicensis) collected during 1982-1984 on evaporation ponds in the San Joaquin Valley, California. Carbonate deposits were composed of about 75% aragonite and 25% calcite, both polymorphous forms of CaCO3. Significantly more carbonate deposits were observed on Ruddy Ducks as length of exposure to agricultural drain water increased, during the 1983-1984 field season when salt concentrations in the ponds were higher, and in certain evaporation-pond systems.

Radium mobility and the age of groundwater in public-drinking-water supplies from the Cambrian-Ordovician aquifer system, north-central USA

USGS Publications Warehouse

Stackelberg, Paul E.; Szabo, Zoltan; Jurgens, Bryant C.

2018-01-01

High radium (Ra) concentrations in potable portions of the Cambrian-Ordovician (C-O) aquifer system were investigated using water-quality data and environmental tracers (3H, 3Hetrit, SF6, 14C and 4Herad) of groundwater age from 80 public-supply wells (PSWs). Groundwater ages were estimated by calibration of tracers to lumped parameter models and ranged from modern (<50 yr) in upgradient, regionally unconfined areas to ancient (>1 Myr) in the most downgradient, confined portions of the potable system. More than 80 and 40 percent of mean groundwater ages were older than 1000 and 50,000 yr, respectively. Anoxic, Fe-reducing conditions and increased mineralization develop with time in the aquifer system and mobilize Ra into solution resulting in the frequent occurrence of combined Ra (Rac = 226Ra + 228Ra) at concentrations exceeding the USEPA MCL of 185 mBq/L (5 pCi/L). The distribution of the three Ra isotopes comprising total Ra (Rat = 224Ra + 226Ra + 228Ra) differed across the aquifer system. The concentrations of 224Ra and 228Ra were strongly correlated and comprised a larger proportion of the Rat concentration in samples from the regionally unconfined area, where arkosic sandstones provide an enhanced source for progeny from the 232Th decay series. 226Ra comprised a larger proportion of the Ratconcentration in samples from downgradient confined regions. Concentrations of Rat were significantly greater in samples from the regionally confined area of the aquifer system because of the increase in 226Ra concentrations there as compared to the regionally unconfined area. 226Ra distribution coefficients decreased substantially with anoxic conditions and increasing ionic strength of groundwater (mineralization), indicating that Ra is mobilized to solution from solid phases of the aquifer as adsorption capacity is diminished. The amount of 226Ra released from solid phases by alpha-recoil mechanisms and retained in solution increases relative to the amount of Ra sequestered by adsorption processes or co-precipitation with barite as adsorption capacity and the concentration of Ba decreases. Although 226Ra occurred at concentrations greater than 224Ra or 228Ra, the ingestion exposure risk was greater for 228Ra owing to its greater toxicity. In addition, 224Ra added substantial alpha-particle radioactivity to potable samples from the C-O aquifer system. Thus, monitoring for Ra isotopes and gross-alpha-activity (GAA) is important in upgradient, regionally unconfined areas as downgradient, and GAA measurements made within 72 h of sample collection would best capture alpha-particle radiation from the short-lived 224Ra.

Biochar and Glomus caledonium Influence Cd Accumulation of Upland Kangkong (Ipomoea aquatica Forsk.) Intercropped with Alfred Stonecrop (Sedum alfredii Hance)

NASA Astrophysics Data System (ADS)

Hu, Junli; Wu, Fuyong; Wu, Shengchun; Lam, Cheung Lung; Lin, Xiangui; Wong, Ming Hung

2014-04-01

Both biochar application and mycorrhizal inoculation have been proposed to improve plant growth and alter bioaccumulation of toxic metals. A greenhouse pot trial was conducted to investigate growth and Cd accumulation of upland kangkong (Ipomoea aquatica Forsk.) intercropped with Alfred stonecrop (Sedum alfredii Hance) in a Cd-contaminated soil inoculated with Glomus caledonium and/or applied with biochar. Compared with the monocultural control, intercropping with stonecrop (IS) decreased kangkong Cd acquisition via rhizosphere competition, and also decreased kangkong yield. Gc inoculation (+M) accelerated growth and Cd acquisition of stonecrop, and hence resulted in further decreases in kangkong Cd acquisition. Regardless of IS and +M, biochar addition (+B) increased kangkong yield via elevating soil available P, and decreased soil Cd phytoavailability and kangkong Cd concentration via increasing soil pH. Compared with the control, the treatment of IS + M + B had a substantially higher kangkong yield (+25.5%) with a lower Cd concentration (-62.7%). Gc generated additive effects on soil alkalinization and Cd stabilization to biochar, causing lower DTPA-extractable (phytoavailable) Cd concentrations and post-harvest transfer risks.

Tuning the Functional Properties of Bitter Vetch (Vicia ervilia) Protein Films Grafted with Spermidine

PubMed Central

Roviello, Valentina; Sabbah, Mohammed

2017-01-01

Bitter vetch protein films containing positively charged spermidine, alone or with low amounts of glycerol, showed high tensile strength that progressively decreased by increasing the plasticizer concentration. Accordingly, lower film elongation at break and higher Young’s module values were detected in the presence of the polyamine without or with small amounts of glycerol. These data suggest that spermidine not only acts as a plasticizer itself by ionically interacting with proteins, but that it also facilitates glycerol-dependent reduction of the intermolecular forces along the protein chains, consequently improving the film flexibility and extensibility. Thus, spermidine may be considered not only as a primary, but also as a secondary plasticizer because of its ability to enhance glycerol plasticizing performance. Such double behavior of the polyamine was confirmed by the film permeability tests, since spermidine increased the barrier properties to gases and water vapor, while glycerol emphasized this effect at low concentrations but led to its marked reversal at high concentrations. Film microscopic images also substantiated these findings, showing more compact, cohesive, and homogeneous matrices in all spermidine-containing films. PMID:29292733

Effect of increasing CO2 on the terrestrial carbon cycle

PubMed Central

Schimel, David; Fisher, Joshua B.

2015-01-01

Feedbacks from the terrestrial carbon cycle significantly affect future climate change. The CO2 concentration dependence of global terrestrial carbon storage is one of the largest and most uncertain feedbacks. Theory predicts the CO2 effect should have a tropical maximum, but a large terrestrial sink has been contradicted by analyses of atmospheric CO2 that do not show large tropical uptake. Our results, however, show significant tropical uptake and, combining tropical and extratropical fluxes, suggest that up to 60% of the present-day terrestrial sink is caused by increasing atmospheric CO2. This conclusion is consistent with a validated subset of atmospheric analyses, but uncertainty remains. Improved model diagnostics and new space-based observations can reduce the uncertainty of tropical and temperate zone carbon flux estimates. This analysis supports a significant feedback to future atmospheric CO2 concentrations from carbon uptake in terrestrial ecosystems caused by rising atmospheric CO2 concentrations. This feedback will have substantial tropical contributions, but the magnitude of future carbon uptake by tropical forests also depends on how they respond to climate change and requires their protection from deforestation. PMID:25548156

Effects of doping and interchain interactions on the metal-insulator transition in trans-polyacetylene

NASA Astrophysics Data System (ADS)

Paulsson, Magnus; Stafström, Sven

1999-09-01

Using a tight-binding Hamiltonian the metal-insulator phase diagram for trans-polyacetylene was calculated as a function of doping concentration and interchain interaction strength. The phase boundary for the periodic system coincides with the gap closing, which occurs for certain combinations of critical values for the doping concentration and the interchain interaction strength. The values found are in good agreement with the experimentally observed increase in the Pauli susceptibility. To simulate disorder in the polymer, the effect of finite chain lengths was studied. This type of disorder pushes the metal/insulator phase boundary towards the metallic side of the phase diagram. An increase in the doping concentration and/or interchain interaction is shown to reduce the localizing effects of disorder effectively. For realistic values of the interchain interaction strength the number of chain breaks needed to localize the states at the Fermi energy is quite small, of the order of a few percent. The localization length is found to be substantially longer than the conjugation length of the polymer.

Interface interactions in benzophenone doped by multiwalled carbon nanotubes

NASA Astrophysics Data System (ADS)

Lebovka, N. I.; Goncharuk, A.; Melnyk, V. I.; Puchkovska, G. A.

2009-08-01

The interface interactions were studied by methods of conductometry, low-temperature phosphorescence and differential scanning calorimetry (DSC) in multiwalled carbon nanotubes (MWCNT) and benzophenone (BP) composite. The concentration of MWCNTs was varied within 0-1 wt%. A percolative threshold was found at MWCNT concentrations exceeding 0.1 wt%. The integration of MWCNTs caused melting temperature increase (≈3 K for 1 wt% of MWCNTs). The effect of positive thermal resistively coefficient, as well as substantial hysteretic behaviour of electrical conductivity σ in a heating-cooling cycle, was observed near the melting point of BP ( T m=321.5 K). The activation-type temperature behaviour of electrical conductivity was observed in the temperature range of supercooled BP. The activation energy was decreasing with increase of MWCNT concentration. The observed nonlinear dependencies of electrical conductivity σ vs. applied voltage U reflect the transport mechanism of the charge carriers through amorphous interface films formed near the surface of the MWCNTs. The thermal shifts of phosphorescence spectra measured within the temperature range 5-200 K evidence existence of such interface films of amorphous BP with width of the order of 0.1 μm.

Indoor secondary pollutants from cleaning product and air freshener use in the presence of ozone

NASA Astrophysics Data System (ADS)

Singer, Brett C.; Coleman, Beverly K.; Destaillats, Hugo; Hodgson, Alfred T.; Lunden, Melissa M.; Weschler, Charles J.; Nazaroff, William W.

This study investigated the formation of secondary pollutants resulting from household product use in the presence of ozone. Experiments were conducted in a 50-m 3 chamber simulating a residential room. The chamber was operated at conditions relevant to US residences in polluted areas during warm-weather seasons: an air exchange rate of 1.0 h -1 and an inlet ozone concentration of approximately 120 ppb, when included. Three products were used in separate experiments. An orange oil-based degreaser and a pine oil-based general-purpose cleaner were used for surface cleaning applications. A plug-in scented-oil air freshener (AFR) was operated for several days. Cleaning products were applied realistically with quantities scaled to simulate residential use rates. Concentrations of organic gases and secondary organic aerosol from the terpene-containing consumer products were measured with and without ozone introduction. In the absence of reactive chemicals, the chamber ozone level was approximately 60 ppb. Ozone was substantially consumed following cleaning product use, mainly by homogeneous reaction. For the AFR, ozone consumption was weaker and heterogeneous reaction with sorbed AFR-constituent VOCs was of similar magnitude to homogeneous reaction with continuously emitted constituents. Formaldehyde generation resulted from product use with ozone present, increasing indoor levels by the order of 10 ppb. Cleaning product use in the presence of ozone generated substantial fine particle concentrations (more than 100 μg m -3) in some experiments. Ozone consumption and elevated hydroxyl radical concentrations persisted for 10-12 h following brief cleaning events, indicating that secondary pollutant production can persist for extended periods.

Mechanisms of nutrient attenuation in a subsurface flow riparian wetland.

PubMed

Casey, R E; Taylor, M D; Klaine, S J

2001-01-01

Riparian wetlands are transition zones between terrestrial and aquatic environments that have the potential to serve as nutrient filters for surface and ground water due to their topographic location. We investigated a riparian wetland that had been receiving intermittent inputs of NO3- and PO4(3-) during storm runoff events to determine the mechanisms of nutrient attenuation in the wetland soils. Few studies have shown whether infrequent pulses of NO3- are sufficient to maintain substantial denitrifying communities. Denitrification rates were highest at the upstream side of the wetland where nutrient-rich runoff first enters the wetland (17-58 microg N2O-N kg soil(-1) h(-1)) and decreased further into the wetland. Carbon limitation for denitrification was minor in the wetland soils. Samples not amended with dextrose had 75% of the denitrification rate of samples with excess dextrose C. Phosphate sorption isotherms suggested that the wetland soils had a high capacity for P retention. The calculated soil PO4(3-) concentration that would yield an equilibrium aqueous P04(3-) concentration of 0.05 mg P L(-1) was found to be 100 times greater than the soil PO4(3-) concentration at the time of sampling. This indicated that the wetland could retain a large additional mass of PO4(3-) without increasing the dissolved P04(3-) concentrations above USEPA recommended levels for lentic waters. These results demonstrated that denitrification can be substantial in systems receiving pulsed NO3- inputs and that sorption could account for extensive PO4(3-) attenuation observed at this site.

Plastic and adaptive responses of plant respiration to changes in atmospheric CO(2) concentration.

PubMed

Gonzàlez-Meler, Miquel A; Blanc-Betes, Elena; Flower, Charles E; Ward, Joy K; Gomez-Casanovas, Nuria

2009-12-01

The concentration of atmospheric CO2 has increased from below 200 microl l(-1) during last glacial maximum in the late Pleistocene to near 280 microl l(-1) at the beginning of the Holocene and has continuously increased since the onset of the industrial revolution. Most responses of plants to increasing atmospheric CO2 levels result in increases in photosynthesis, water use efficiency and biomass. Less known is the role that respiration may play during adaptive responses of plants to changes in atmospheric CO2. Although plant respiration does not increase proportionally with CO2-enhanced photosynthesis or growth rates, a reduction in respiratory costs in plants grown at subambient CO2 can aid in maintaining a positive plant C-balance (i.e. enhancing the photosynthesis-to-respiration ratio). The understanding of plant respiration is further complicated by the presence of the alternative pathway that consumes photosynthate without producing chemical energy [adenosine triphosphate (ATP)] as effectively as respiration through the normal cytochrome pathway. Here, we present the respiratory responses of Arabidopsis thaliana plants selected at Pleistocene (200 microl l(-1)), current Holocene (370 microl l(-1)), and elevated (700 microl l(-1)) concentrations of CO2 and grown at current CO2 levels. We found that respiration rates were lower in Pleistocene-adapted plants when compared with Holocene ones, and that a substantial reduction in respiration was because of reduced activity of the alternative pathway. In a survey of the literature, we found that changes in respiration across plant growth forms and CO2 levels can be explained in part by differences in the respiratory energy demand for maintenance of biomass. This trend was substantiated in the Arabidopsis experiment in which Pleistocene-adapted plants exhibited decreases in respiration without concurrent reductions in tissue N content. Interestingly, N-based respiration rates of plants adapted to elevated CO2 also decreased. As a result, ATP yields per unit of N increased in Pleistocene-adapted plants compared with current CO2 adapted ones. Our results suggest that mitochondrial energy coupling and alternative pathway-mediated responses of respiration to changes in atmospheric CO2 may enhance survival of plants at low CO2 levels to help overcome a low carbon balance. Therefore, increases in the basal activity of the alternative pathway are not necessarily associated to metabolic plant stress in all cases.

Human-relevant Levels of Added Sugar Consumption Increase Female Mortality and Lower Male Fitness in Mice

PubMed Central

Ruff, James S.; Suchy, Amanda K.; Hugentobler, Sara A.; Sosa, Mirtha M.; Schwartz, Bradley L.; Morrison, Linda C.; Gieng, Sin H.; Shigenaga, Mark K.; Potts, Wayne K.

2013-01-01

Consumption of added sugar has increased over recent decades and is correlated with numerous diseases. Rodent models have elucidated mechanisms of toxicity, but only at concentrations beyond typical human exposure. Here we show that comparatively low levels of added sugar consumption have substantial negative effects on mouse survival, competitive ability, and reproduction. Using Organismal Performance Assays (OPAs) – in which mice fed human-relevant concentrations of added sugar (25% Kcal from a mixture of fructose and glucose [F/G]) and control mice compete in seminatural enclosures for territories, resources and mates – we demonstrate that F/G-fed females experience a two-fold increase in mortality while F/G-fed males control 26% fewer territories and produce 25% less offspring. These findings represent the lowest level of sugar consumption shown to adversely affect mammalian health. Clinical defects of F/G-fed mice were decreased glucose clearance and increased fasting cholesterol. Our data highlight that physiological adversity can exist when clinical disruptions are minor, and suggest that OPAs represent a promising technique for unmasking negative effects of toxicants. PMID:23941916

The impact of inland ships and recreational boats on measured NOx and ultrafine particle concentrations along the waterways

NASA Astrophysics Data System (ADS)

van der Zee, Saskia C.; Dijkema, Marieke B. A.; van der Laan, Jorrit; Hoek, Gerard

2012-08-01

In Amsterdam, many inhabitants reside in proximity to inland waters. The aim of this study was to assess the impact of passing inland ships and recreational boats, including touring boats, on the air quality near houses close to the water. A measurement campaign was performed at five sites in Amsterdam. Two sites were located along the inland waterways used by cargo ships and recreational boats. The other three sites were located along the canals in the historical city centre, used by touring boats and private recreational boats. At each site, measurements were performed at the waterside and at the facade of houses. Nitrogen oxides (NO and NO2) and ultrafine particles (particle number (PN) concentration), were measured continuously during one afternoon per site, while time and type of passing ships and road traffic was registered. Linear regression analysis was used to analyze the association between passing ships and concentration, adjusted for passing road traffic. There was substantial variation in the impact of passing ships on concentrations at each measuring site, as well as between sites. On average, cargo ships contributed 5 and 4 μg m-3 to NO and NO2, respectively, and 3000 particles cm-3 to PN concentration near houses during the sampling period. Peak concentrations were occasionally substantially higher. Emissions from touring boats had a small but significant impact on NO concentration near houses but not on NO2, with the exception of one site located near the edge of two canals, where boats use extra power to travel around the bent. At this site, touring boats contributed 5 μg m-3 to the local NO2 concentration. No consistent impact of touring boats on PN concentration was observed. Emissions from private recreational boats were not consistently associated with increased NOx or PN concentration. Road traffic intensity was low at the selected measurement sites. Nevertheless, a significant impact of passing diesel-operated delivery vans on house adjacent concentrations of both NOx and PN concentrations was found. On average, mopeds had a small but significant impact on PN concentration by 1100 particles cm-3 In conclusion, this study provides evidence that ship exhausts has an impact on air quality near houses along waterways.

[Clinical hygienic substantiation for the individual biocorrection of ecologically dependent conditions in the critical population groups industrial areas of Ukraine].

PubMed

Beletskaya, E N; Onul, N M; Glavatskaya, V I; Antonova, E V; Golovkova, T A

2014-01-01

In the article there is considered the problem of environmental and human body pollution with heavy metals, the effectiveness of individual biocorrection in critical population groups--pregnant females and children residing in technologically contaminated areas. It was established that, in spite of the correspondence of the content of abiotic heavy metals to their MACs in the environment, the concentration of lead and cadmium in the internal environment of the organism is 1,6-15,4 times larger than physiological norms and accompanied by substantial deficiency of essential trace elements. The similar situation in children was proved to cause the fall in mental capacity and learning ability, in pregnant females--to various complications. The obtained results were the scientific substantiation for the feasibility of performing of biocorrection for trace elements imbalance and ecologically dependent conditions in the population of the industrial region, proved its high clinical and hygienic efficiency, which is the basis for the wide introduction of pectin containing preparations with the aim to enforce the health, prevent ecologically dependent conditions and increasing the adaptive capacity of the organism.

Diurnal variability of polycyclic aromatic compound (PAC) concentrations: Relationship with meteorological conditions and inferred sources

NASA Astrophysics Data System (ADS)

Alam, Mohammed S.; Keyte, Ian J.; Yin, Jianxin; Stark, Christopher; Jones, Alan M.; Harrison, Roy M.

2015-12-01

Polycyclic aromatic hydrocarbons (PAH) and their nitro and oxy derivatives have been sampled every three hours over one week in winter at two sites in Birmingham UK. One site is heavily influenced by road traffic and is close to residential dwellings, while the other site is a background urban location at some distance from both sources of emission. The time series of concentrations has been examined along with the ratio of concentrations between the two sampling sites. A comparison of averaged diurnal profiles has shown different patterns of behaviour which has been investigated through calculating ratios of concentration at 18:00-21:00 h relative to that at 06:00-09:00 h. This allows identification of those compounds with a strong contribution to a traffic-related maximum at 06:00-09:00 h which are predominantly the low molecular weight PAHs, together with a substantial group of quinones and nitro-PAHs. Changes in partitioning between vapour and particulate forms are unlikely to influence the ratio as the mean temperature at both times was almost identical. Most compounds show an appreciable increase in concentrations in the evening which is attributed to residential heating emissions. Compounds dominated by this source show high ratios of 18:00-21:00 concentrations relative to 06:00-09:00 concentrations and include higher molecular weight PAH and a substantial group of both quinones and nitro-PAH. The behaviour of retene, normally taken as an indicator of biomass burning, is suggestive of wood smoke only being one contributor to the evening peak in PAH and their derivatives, with coal combustion presumably being the other main contributor. Variations of PAH concentrations with wind speed show a dilution behaviour consistent with other primary pollutants, and high concentrations of a range of air pollutants were observed in an episode of low temperatures and low wind speeds towards the end of the overall sampling period consistent with poor local dispersion processes. Results from a short summer campaign give indications of the formation of some nitro-PAH by atmospheric chemical reactions.

Remarkable changes in interface O vacancy and metal-oxide bonds in amorphous indium-gallium-zinc-oxide thin-film transistors by long time annealing at 250 °C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chowdhury, Md Delwar Hossain; Um, Jae Gwang; Jang, Jin, E-mail: jjang@khu.ac.kr

We have studied the effect of long time post-fabrication annealing on negative bias illumination stress (NBIS) of amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film-transistors. Annealing for 100 h at 250 °C increased the field effect mobility from 14.7 cm{sup 2}/V s to 17.9 cm{sup 2}/V s and reduced the NBIS instability remarkably. Using X-ray photoelectron spectroscopy, the oxygen vacancy and OH were found to exist at the interfaces of a-IGZO with top and bottom SiO{sub 2}. Long time annealing helps to decrease the vacancy concentration and increase the metal-oxygen bonds at the interfaces; this leads to increase in the free carrier concentrations in a-IGZO and field-effect mobility.more » X-ray reflectivity measurement indicated the increment of a-IGZO film density of 5.63 g cm{sup −3} to 5.83 g cm{sup −3} (3.4% increase) by 100 h annealing at 250 °C. The increase in film density reveals the decrease of O vacancy concentration and reduction of weak metal-oxygen bonds in a-IGZO, which substantially helps to improve the NBIS stability.« less

In-vehicle exposures to particulate air pollution in Canadian metropolitan areas: the urban transportation exposure study.

PubMed

Weichenthal, Scott; Van Ryswyk, Keith; Kulka, Ryan; Sun, Liu; Wallace, Lance; Joseph, Lawrence

2015-01-06

Commuters may be exposed to increased levels of traffic-related air pollution owing to close proximity to traffic-emissions. We collected in-vehicle and roof-top air pollution measurements over 238 commutes in Montreal, Toronto, and Vancouver, Canada between 2010 and 2013. Voice recordings were used to collect real-time information on traffic density and the presence of diesel vehicles and multivariable linear regression models were used to estimate the impact of these factors on in-vehicle pollutant concentrations (and indoor/outdoor ratios) along with parameters for road type, land use, and meteorology. In-vehicle PM2.5 and NO2 concentrations consistently exceeded regional outdoor levels and each unit increase in the rate of encountering diesel vehicles (count/min) was associated with substantial increases (>100%) in in-vehicle concentrations of ultrafine particles (UFPs), black carbon, and PM2.5 as well as strong increases (>15%) in indoor/outdoor ratios. A model based on meteorology and the length of highway roads within a 500 m buffer explained 53% of the variation in in-vehicle UFPs; however, models for PM2.5 (R(2) = 0.24) and black carbon (R(2) = 0.30) did not perform as well. Our findings suggest that vehicle commuters experience increased exposure to air pollutants and that traffic characteristics, land use, road types, and meteorology are important determinants of these exposures.

An approach toward incorporation of global warming effects into Intensity-Duration-Frequency values

NASA Astrophysics Data System (ADS)

Kunkel, K.; Easterling, D. R.

2017-12-01

Rising global temperatures from increasing greenhouse gas concentrations will increase overall atmospheric water vapor concentrations. There is a high level of scientific confidence that this will increase the future intensity and frequency of extreme precipitation events, even in regions where overall precipitation may decrease. For control of runoff from extreme rainfall, infrastructure engineering utilizes design values of rainfall known as Intensity-Duration-Frequency (IDF) values. Use of the existing IDF values, which are based solely on historical climate records, is likely to lead to under-design of runoff control structures, and associated increased flood damages. However, future changes in IDF values are uncertain and probably regionally variable. Our paradigm is that changes in IDF values will result from changes in atmospheric capacity (water vapor concentrations) and opportunity (the number and intensity of heavy precipitation-producing storm systems). Relevant storm systems being investigated include extratropical cyclones and their associated fronts, tropical cyclones, and the North American Monsoon system. The overall approach involves developing IDF adjustment factors for changes in these components of the climate system. The adjustment factors have associated uncertainties, primarily from (1) uncertainties in the future pathway of greenhouse gas emissions and (2) variations among climate models in the sensitivity of the climate system to greenhouse gas concentration changes. In addition to meteorological considerations, the lifetime of projects designed using IDF values is an essential consideration because the IDF values may change substantially during that time. The initial results of this project will be discussed.

Performance and exposure indices of rats exposed to low concentrations of lead.

PubMed

Cory-Slechta, D A; Weiss, B; Cox, C

1985-04-01

To further characterize the lower end of the function relating lead exposure and biological exposure indices to behavior, male weanling rats were exposed chronically to drinking solutions containing 25 ppm sodium acetate (controls) or 25 ppm lead acetate. Behavioral training began when the animals reached 50 days of age, and performance on a fixed-interval 1-min schedule of food reinforcement was then assessed over 90 experimental sessions (136 days). This exposure produced overall response rate increases over the first 40 sessions that were similar to those observed previously with higher concentrations of lead. Response rates of the two groups tended to merge subsequently. The increased overall response rates in the treated group derived primarily from an increased frequency of shorter interresponse times (IRTs) and increased running rates (calculated without the postreinforcement interval). Blood lead (PbB) and zinc protoporphyrin (ZPP) values were determined following sessions 30, 60, and 90. PbB values of the lead-exposed group averaged 15 to 20 micrograms/dl throughout the study; ZPP did not differ. The mean brain lead value of the treated group was 0.07 micrograms Pb/g. Blood-brain ratios (1.38 to 4.06) were substantially greater than those previously observed at higher exposures. These data extend to even lower exposures, and lower blood lead concentrations, the effective concentration for behavioral effects, and further emphasize the importance of the sensitivity of the endpoint in assessing behavioral toxicity.

Effects of an in vacancy on local distortion of fast phase transition in Bi-doped In3SbTe2

NASA Astrophysics Data System (ADS)

Choi, Minho; Choi, Heechae; Kim, Seungchul; Ahn, Jinho; Kim, Yong Tae

2017-12-01

Indium vacancies in Bi-doped In3SbTe2 (BIST) cause local distortion or and faster phase transition of BIST with good stability. The formation energy of the In vacancy in the BIST is relatively lower compared to that in IST due to triple negative charge state of the In vacancy ( V 3- In) and higher concentration of the V 3- In in BIST. The band gap of BIST is substantially reduced with increasing concentrations of the V 3- In and the hole carriers, which results in a higher electrical conductivity. The phase-change memory (PRAM) device fabricated with the BIST shows very fast, stable switching characteristics at lower voltages.

[Alkalosis].

PubMed

Kościelska, Malgorzata; Mieczkowski, Mariusz

2013-01-01

An elevation of arterial blood pH called alkalosis remains an underestimated condition in hospitalized patients. Serious alkalosis can be associated with high risk of death. The disorder can be caused by increased concentration of bicarbonate (metabolic alkalosis) or decreased concentration of carbon dioxide (respiratory alkalosis). In most cases of metabolic alkalosis it is generated by vomiting or diuretic use, whereas respiratory alkalosis is provoked by hyperventilation associated with respiratory or neurological disorder. Maintenance of metabolic alkalosis is possible only in patients with impaired renal base excretion which is most often produced by hypochloremia. In both respiratory and metabolic alkaloses treatment depends on the underlying factor. In hyperventilation syndrome is based on behavioral therapy. In most cases of metabolic alkalosis the administration of sodium and potassium chloride forms a substantial part of therapy.

Increased Extreme Hydrological Events and Decreased Water Supply Availability for the Southwestern United States Projected by Mid-Century

NASA Astrophysics Data System (ADS)

Pagan, B. R.; Ashfaq, M.; Rastogi, D.; Naz, B. S.; Kao, S. C.; Mei, R.; Kendall, D. R.; Pal, J. S.

2014-12-01

Semi-arid Southern California relies primarily on imported water originating mostly from snowpack in basins outside of the region including the San-Joaquin River, Tulare Lake, Sacramento River, Owens Valley, Mono Lake, and Colorado River basins. This study provides an integrated ensemble approach to assessing climate change impacts on the hydrologic cycle and hydrologic extremes for all water supplies to Southern California. Output from 10 global climate models is used to force a regional climate model and hydrological model resulting in high-resolution 4.17-km output for the region. Greenhouse gas concentrations are prescribed according to historical values for the present-day (1965-2005) and the IPCC Representative Concentration Pathway 8.5 for the near to mid term future (2010-2050). On the annual timescale, temperature, precipitation and evaporation increase throughout the majority of the study area. With increased temperatures, precipitation is less likely to fall as snow, decreasing snowpack and natural storage and shifting peak flows to earlier in the year. Daily annual maximum runoff and precipitation events are projected to significantly increase in intensity and frequency by mid-century. The 50-year event, for example, becomes approximately five times more likely in the Colorado River basin and twice as likely in the other basins. In densely populated coastal Southern Californian cities, extreme flood events become three to five times as likely substantially increasing the risk of overburdening flood control systems and potential widespread flooding. The escalating likelihood of the combined effects of runoff occurring earlier in the year and in significantly higher amounts poses a substantial flood control risk requiring adaptation measures such as water release from reservoirs. Significant snowpack reductions and increased flood risk will likely necessitate additional multiyear storage solutions for urban and agricultural regions in the Southwestern US.

Increased Extreme Hydrological Events and Decreased Water Supply Availability for the Southwestern United States Projected by Mid-Century

NASA Astrophysics Data System (ADS)

Pagan, B. R.; Ashfaq, M.; Rastogi, D.; Naz, B. S.; Kao, S. C.; Mei, R.; Kendall, D. R.; Pal, J. S.

2015-12-01

Semi-arid Southern California relies primarily on imported water originating mostly from snowpack in basins outside of the region including the San-Joaquin River, Tulare Lake, Sacramento River, Owens Valley, Mono Lake, and Colorado River basins. This study provides an integrated ensemble approach to assessing climate change impacts on the hydrologic cycle and hydrologic extremes for all water supplies to Southern California. Output from 10 global climate models is used to force a regional climate model and hydrological model resulting in high-resolution 4.17-km output for the region. Greenhouse gas concentrations are prescribed according to historical values for the present-day (1965-2005) and the IPCC Representative Concentration Pathway 8.5 for the near to mid term future (2010-2050). On the annual timescale, temperature, precipitation and evaporation increase throughout the majority of the study area. With increased temperatures, precipitation is less likely to fall as snow, decreasing snowpack and natural storage and shifting peak flows to earlier in the year. Daily annual maximum runoff and precipitation events are projected to significantly increase in intensity and frequency by mid-century. The 50-year event, for example, becomes approximately five times more likely in the Colorado River basin and twice as likely in the other basins. In densely populated coastal Southern Californian cities, extreme flood events become three to five times as likely substantially increasing the risk of overburdening flood control systems and potential widespread flooding. The escalating likelihood of the combined effects of runoff occurring earlier in the year and in significantly higher amounts poses a substantial flood control risk requiring adaptation measures such as water release from reservoirs. Significant snowpack reductions and increased flood risk will likely necessitate additional multiyear storage solutions for urban and agricultural regions in the Southwestern US.

Dynamic behaviour of river colloidal and dissolved organic matter through cross-flow ultrafiltration system.

PubMed

Wilding, Andrew; Liu, Ruixia; Zhou, John L

2005-07-01

Through cross-flow filtration (CFF) with a 1-kDa regenerated cellulose Pellicon 2 module, the ultrafiltration characteristics of river organic matter from Longford Stream, UK, were investigated. The concentration of organic carbon (OC) in the retentate in the Longford Stream samples increased substantially with the concentration factor (cf), reaching approximately 40 mg/L at cf 15. The results of dissolved organic carbon (DOC) and colloidal organic carbon (COC) analysis, tracking the isolation of colloids from river waters, show that 2 mg/L of COC was present in those samples and good OC mass balance (77-101%) was achieved. Fluorescence measurements were carried out for the investigation of retentate and permeate behaviour of coloured dissolved organic materials (CDOM). The concentrations of CDOM in both the retentate and permeate increased with increasing cf, although CDOM were significantly more concentrated in the retentate. The permeation model expressing the correlation between log[CDOM] in the permeate and logcf was able to describe the permeation behaviour of CDOM in the river water with regression coefficients (r(2)) of 0.94 and 0.98. Dry weight analysis indicated that the levels of organic colloidal particles were from 49 to 71%, and between 29 and 51% of colloidal particles present were inorganic. COC as a percentage of DOC was found to be 10-16% for Longford Stream samples.

Mercury Methylation by Desulfovibrio desulfuricans ND132 in the Presence of Polysulfides

PubMed Central

Jay, Jenny Ayla; Murray, Karen J.; Gilmour, Cynthia C.; Mason, Robert P.; Morel, François M. M.; Roberts, A. Lynn; Hemond, Harold F.

2002-01-01

The extracellular speciation of mercury may control bacterial uptake and methylation. Mercury-polysulfide complexes have recently been shown to be prevalent in sulfidic waters containing zero-valent sulfur. Despite substantial increases in total dissolved mercury concentration, methylation rates in cultures of Desulfovibrio desulfuricans ND132 equilibrated with cinnabar did not increase in the presence of polysulfides, as expected due to the large size and charged nature of most of the complexes. In natural waters not at saturation with cinnabar, mercury-polysulfide complexes would be expected to shift the speciation of mercury from HgS0(aq) toward charged complexes, thereby decreasing methylation rates. PMID:12406773

Estimating personal exposures from ambient air-pollution measures: Using meta-analysis to assess measurement error

PubMed Central

Holliday, Katelyn M; Avery, Christy L; Poole, Charles; McGraw, Kathleen; Williams, Ronald; Liao, Duanping; Smith, Richard L; Whitsel, Eric A

2014-01-01

Background Although ambient concentrations of particulate matter ≤10μm (PM10) are often used as proxies for total personal exposure, correlation (r) between ambient and personal PM10 concentrations varies. Factors underlying this variation and its effect on health outcome-PM exposure relationships remain poorly understood. Methods We conducted a random-effects meta-analysis to estimate effects of study, participant and environmental factors on r; used the estimates to impute personal exposure from ambient PM10 concentrations among 4,012 non-smoking, diabetic participants in the Women’s Health Initiative clinical trial; and then estimated the associations of ambient and imputed personal PM10 concentrations with electrocardiographic measures such as heart rate variability. Results We identified fifteen studies (in years 1990-2009) of 342 participants in five countries. The median r was 0.46 (range = 0.13 to 0.72). There was little evidence of funnel-plot asymmetry but substantial heterogeneity of r, which increased 0.05 (95% confidence interval [CI]= 0.01 to 0.09) per 10 μg/m3 increase in mean ambient PM10 concentration. Substituting imputed personal exposure for ambient PM10 concentrations shifted mean percent changes in electrocardiographic measures per 10μg/m3 increase in exposure away from the null and decreased their precision, e.g. −2.0% (95% CI= −4.6% to 0.7%) versus −7.9% (−15.9% to 0.9%) for the standard deviation of normal-to-normal RR interval duration. Conclusions Analogous distributions and heterogeneity of r in extant meta-analyses of ambient and personal PM2.5 concentrations suggest that observed shifts in mean percent change and decreases in precision may be generalizable across particle size. PMID:24220191

Influence of solid noise barriers on near-road and on-road air quality

NASA Astrophysics Data System (ADS)

Baldauf, Richard W.; Isakov, Vlad; Deshmukh, Parikshit; Venkatram, Akula; Yang, Bo; Zhang, K. Max

2016-03-01

Public health concerns regarding adverse health effects for populations spending significant amounts of time near high traffic roadways has increased substantially in recent years. Roadside features, including solid noise barriers, have been investigated as potential methods that can be implemented in a relatively short time period to reduce air pollution exposures from nearby traffic. A field study was conducted to determine the influence of noise barriers on both on-road and downwind pollutant concentrations near a large highway in Phoenix, Arizona, USA. Concentrations of nitrogen dioxide, carbon monoxide, ultrafine particles, and black carbon were measured using a mobile platform and fixed sites along two limited-access stretches of highway that contained a section of noise barrier and a section with no noise barrier at-grade with the surrounding terrain. Results of the study showed that pollutant concentrations behind the roadside barriers were significantly lower relative to those measured in the absence of barriers. The reductions ranged from 50% within 50 m from the barrier to about 30% as far as 300 m from the barrier. Reductions in pollutant concentrations generally began within the first 50 m of the barrier edge; however, concentrations were highly variable due to vehicle activity behind the barrier and along nearby urban arterial roadways. The concentrations on the highway, upwind of the barrier, varied depending on wind direction. Overall, the on-road concentrations in front of the noise barrier were similar to those measured in the absence of the barrier, contradicting previous modeling results that suggested roadside barriers increase pollutant levels on the road. Thus, this study suggests that noise barriers do reduce potential pollutant exposures for populations downwind of the road, and do not likely increase exposures to traffic-related pollutants for vehicle passengers on the highway.

Cationic permethylated 6-monoamino-6-monodeoxy-β-cyclodextrin as chiral selector of dansylated amino acids in capillary electrophoresis.

PubMed

Németh, Krisztina; Domonkos, Celesztina; Sarnyai, Virág; Szemán, Julianna; Jicsinszky, László; Szente, Lajos; Visy, Júlia

2014-10-01

The resolution power of permethylated 6-monoamino-6-monodeoxy-βCD (PMMABCD) - a single isomer, cationic CD derivative - developed previously for chiral analyses in capillary electrophoresis was further studied here. Dansylated amino acids (Dns-AA) were chosen as amphoteric chiral model compounds. Changes in the resolutions of Dns-AAs by varying pH and selector concentrations were investigated and correlated with their structures and chemical properties (isoelectric point and lipophilicity). Maximal resolutions could be achieved at pH 6 or pH 4. The separations improved with increasing concentration of the selector. Baseline or substantially better resolution for 8 pairs of these Dns-AAs could be achieved. Low CD concentration was enough for the separation of the most apolar Dns-AAs. Chiral discrimination ability of PMMABCD was demonstrated by the separation of an artificial mixture of 8 Dns-AA pairs. Copyright © 2014 Elsevier B.V. All rights reserved.

Body distribution of nanoparticle-containing adriamycin injected into the hepatic artery of hepatoma-bearing rats.

PubMed

Chen, Jiang-Hao; Wang, Ling; Ling, Rui; Li, Yu; Wang, Zhe; Yao, Qing; Ma, Zhong

2004-08-01

The aim of the study was to investigate the body distribution of nanoparticle-containing adriamycin (NADR) injected into the hepatic artery of hepatoma-bearing rats. Thirty Walker-256 hepatoma-bearing rats were divided into two groups at random, with 15 rats in each. NADR and free adriamycin (FADR) were injected into the hepatic artery of animals on the seventh day after tumor implantation. At 1, 5, and 15 hr, after administration, five animals in each group were sacrificed and the ADR concentrations in the plasma, liver, heart, spleen, lungs, kidneys, and tumor were determined. The results showed that NADR substantially increased the ADR concentrations in liver, spleen, and tumor of rats compared to FADR, whereas the concentrations in plasma, heart, and lungs were significantly decreased. In conclusion, the body distribution of ADR can be modified by its encapsulation into nanoparticles and administration via the hepatic artery.

Hydrological effects of the increased CO2 and climate change in the Upper Mississippi River Basin using a modified SWAT

USGS Publications Warehouse

Wu, Y.; Liu, S.; Abdul-Aziz, O. I.

2012-01-01

Increased atmospheric CO2 concentration and climate change may significantly impact the hydrological and meteorological processes of a watershed system. Quantifying and understanding hydrological responses to elevated ambient CO2 and climate change is, therefore, critical for formulating adaptive strategies for an appropriate management of water resources. In this study, the Soil and Water Assessment Tool (SWAT) model was applied to assess the effects of increased CO2 concentration and climate change in the Upper Mississippi River Basin (UMRB). The standard SWAT model was modified to represent more mechanistic vegetation type specific responses of stomatal conductance reduction and leaf area increase to elevated CO2 based on physiological studies. For estimating the historical impacts of increased CO2 in the recent past decades, the incremental (i.e., dynamic) rises of CO2 concentration at a monthly time-scale were also introduced into the model. Our study results indicated that about 1–4% of the streamflow in the UMRB during 1986 through 2008 could be attributed to the elevated CO2 concentration. In addition to evaluating a range of future climate sensitivity scenarios, the climate projections by four General Circulation Models (GCMs) under different greenhouse gas emission scenarios were used to predict the hydrological effects in the late twenty-first century (2071–2100). Our simulations demonstrated that the water yield would increase in spring and substantially decrease in summer, while soil moisture would rise in spring and decline in summer. Such an uneven distribution of water with higher variability compared to the baseline level (1961–1990) may cause an increased risk of both flooding and drought events in the basin.

Reversible amorphous-crystalline phase changes in a wide range of Se1-xTex alloys studied using ultrafast differential scanning calorimetry

NASA Astrophysics Data System (ADS)

Vermeulen, Paul. A.; Momand, Jamo; Kooi, Bart J.

2014-07-01

The reversible amorphous-crystalline phase change in a chalcogenide material, specifically the Se1-xTex alloy, has been investigated for the first time using ultrafast differential scanning calorimetry. Heating rates and cooling rates up to 5000 K/s were used. Repeated reversible amorphous-crystalline phase switching was achieved by consecutively melting, melt-quenching, and recrystallizing upon heating. Using a well-conditioned method, the composition of a single sample was allowed to shift slowly from 15 at. %Te to 60 at. %Te, eliminating sample-to-sample variability from the measurements. Using Energy Dispersive X-ray Spectroscopy composition analysis, the onset of melting for different Te-concentrations was confirmed to coincide with the literature solidus line, validating the use of the onset of melting Tm as a composition indicator. The glass transition Tg and crystallization temperature Tc could be determined accurately, allowing the construction of extended phase diagrams. It was found that Tm and Tg increase (but Tg/Tm decrease slightly) with increasing Te-concentration. Contrarily, the Tc decreases substantially, indicating that the amorphous phase becomes progressively unfavorable. This coincides well with the observation that the critical quench rate to prevent crystallization increases about three orders of magnitude with increasing Te concentration. Due to the employment of a large range of heating rates, non-Arrhenius behavior was detected, indicating that the undercooled liquid SeTe is a fragile liquid. The activation energy of crystallization was found to increase 0.5-0.6 eV when the Te concentration increases from 15 to 30 at. % Te, but it ceases to increase when approaching 50 at. % Te.

Rapid increase of ozone concentrations in Xi'an, China: Anthropogenically or naturally?

NASA Astrophysics Data System (ADS)

Wu, J.; Li, G.; Junji, C.

2017-12-01

The air quality in the Guanzhong basin, China has deteriorated recently caused by growing industries, city expansions, and increasing transportation activity. We report here a substantial increasing trend of ozone (O3) concentrations in Xi'an, the largest city of the basin, and the average observed O3 concentration in the afternoon during summertime has increased by 39% from 2013 to 2016. There are two main possible reasons for the rapid O3 increase. Motor vehicle has been reported to increase by 35% in Xi'an, which enhances the O3 precursors emissions to facilitate the O3 formation. In addition, the surface solar radiation at the meteorological site in Xi'an has been observed to intensify by 30%, which increases the photolysis rates to expedite the O3 production. A persistent high O3 episode from 16 to 22 June 2016 in Xi'an has been simulated using the WRF-CHEM model to evaluate the contribution of the transportation emission and solar radiation enhancement on the O3 trend. The model generally performs reasonably well in simulating the temporal variation and spatial distribution of near-surface O3 and NO2 concentrations against measurements in Xi'an. Sensitivity studies have revealed that the enhancement of transportation emissions and the solar radiation explains about 70% of the O3 trend from 2013 to 2016. Considering that large amounts of biogenic emissions are released over the Qinling Mountains on the south of Xi'an, which can be delivered to Xi'an under favorable meteorological conditions, enhancing O3 formation. Therefore, future studies need to be performed to evaluate impacts of the solar radiation enhancement on the biogenic emissions and further the O3 formation in Xi'an.

Influence of the chlorine concentration on the radiation efficiency of a XeCl exciplex lamp

NASA Astrophysics Data System (ADS)

Avtaeva, S. V.; Sosnin, E. A.; Saghi, B.; Panarin, V. A.; Rahmani, B.

2013-09-01

The influence of the chlorine concentration on the radiation efficiency of coaxial exciplex lamps (excilamps) excited by a dielectric barrier discharge (DBD) in binary Xe-Cl2 mixtures at pressures of 240-250 Torr is investigated experimentally and theoretically. The experiments were carried out at Cl2 concentrations in the range of 0.01-1%. The DBD characteristics were calculated in the framework of a one-dimensional hydrodynamic model at Cl2 concentrations in the range of 0.1-5%. It is found that the radiation intensities of the emission bands of Xe*2(172 nm) and XeCl* (308 nm) are comparable when the chlorine concentration in the mixture is in the range of 0.01-0.1%. In this case, in the mixture, the radiation intensity of the Xe*2 molecule rapidly decreases with increasing Cl2 concentration and, at a chlorine concentration of ≥0.2%, the radiation of the B → X band of XeCl* molecules with a peak at 308 nm dominates in the discharge radiation. The radiation efficiency of this band reaches its maximum value at chlorine concentrations in the range of 0.4-0.5%. The calculated efficiencies of DBD radiation exceed those obtained experimentally. This is due to limitations of the one-dimensional model, which assumes the discharge to be uniform in the transverse direction, whereas the actual excilamp discharge is highly inhomogeneous. The influence of the chlorine concentration on the properties of the DBD plasma in binary Xe-Cl2 mixtures is studied numerically. It is shown that an increase in the Cl2 concentration in the mixture leads to the attachment of electrons to chlorine atoms and a decrease in the electron density and discharge conductivity. As a result, the electric field and the voltage drop across the discharge gap increase, which, in turn, leads to an increase in the average electron energy and the probability of dissociation of Cl2 molecules and ionization of Xe atoms and Cl2 molecules. The total energy deposited in the discharge rises with increasing chlorine concentration due to an increase in the power spent on the heating of positive and negative ions. The power dissipated by electrons decreases with increasing chlorine concentration in the working mixture. Recommendations on the choice of the chlorine content in the mixture for reducing the intensity of VUV radiation of the second continuum of the Xe*2 excimer without a substantial decrease in the excilamp efficiency are formulated.

Assessment of hydrology, water quality, and trace elements in selected placer-mined creeks in the birch creek watershed near central, Alaska, 2001-05

USGS Publications Warehouse

Kennedy, Ben W.; Langley, Dustin E.

2007-01-01

Executive Summary The U.S. Geological Survey, in cooperation with the Bureau of Land Management, completed an assessment of hydrology, water quality, and trace-element concentrations in streambed sediment of the upper Birch Creek watershed near Central, Alaska. The assessment covered one site on upper Birch Creek and paired sites, upstream and downstream from mined areas, on Frying Pan Creek and Harrison Creek. Stream-discharge and suspended-sediment concentration data collected at other selected mined and unmined sites helped characterize conditions in the upper Birch Creek watershed. The purpose of the project was to provide the Bureau of Land Management with baseline information to evaluate watershed water quality and plan reclamation efforts. Data collection began in September 2001 and ended in September 2005. There were substantial geomorphic disturbances in the stream channel and flood plain along several miles of Harrison Creek. Placer mining has physically altered the natural stream channel morphology and removed streamside vegetation. There has been little or no effort to re-contour waste rock piles. During high-flow events, the abandoned placer-mine areas on Harrison Creek will likely contribute large quantities of sediment downstream unless the mined areas are reclaimed. During 2004 and 2005, no substantial changes in nutrient or major-ion concentrations were detected in water samples collected upstream from mined areas compared with water samples collected downstream from mined areas on Frying Pan Creek and Harrison Creek that could not be attributed to natural variation. This also was true for dissolved oxygen, pH, and specific conductance-a measure of total dissolved solids. Sample sites downstream from mined areas on Harrison Creek and Frying Pan Creek had higher median suspended-sediment concentrations, by a few milligrams per liter, than respective upstream sites. However, it is difficult to attach much importance to the small downstream increase, less than 10 milligrams per liter, in median suspended-sediment concentration for either basin. During low-flow conditions in 2004 and 2005, previously mined areas investigated on Harrison Creek and on Frying Pan Creek did not contribute substantial suspended sediments to sample sites downstream from the mined areas. No substantial mining-related water- or sediment-quality problems were detected at any of the sites investigated in the upper Birch Creek watershed during low-flow conditions. Average annual streamflow and precipitation were near normal in 2002 and 2003. Drought conditions, extreme forest fire impact, and low annual streamflow set apart the 2004 and 2005 summer seasons. Daily mean streamflow for upper Birch Creek varied throughout the period of record-from maximums of about 1,000 cubic feet per second to minimums of about 20 cubic feet per second. Streamflow increased and decreased rapidly in response to rainfall and rapid snowmelt events because the steep slopes, thin soil cover, and permafrost areas in the watershed have little capacity to retain runoff. Median suspended-sediment concentrations for the 115 paired samples from Frying Pan Creek and 101 paired samples from Harrison Creek were less than the 20 milligrams per liter total maximum daily load. The total maximum daily load was set by the U.S. Environmental Protection Agency for the upper Birch Creek basin in 1996. Suspended-sediment paired-sample data were collected using automated samplers in 2004 and 2005, primarily during low-flow conditions. Suspended-sediment concentrations in grab samples from miscellaneous sites ranged from less than 1 milligram per liter during low-flow conditions to 1,386 milligrams per liter during a high-flow event on upper Birch Creek. Streambed-sediment samples were collected at six sites on Harrison Creek, two sites on Frying Pan Creek, and one site on upper Birch Creek. Trace-element concentrations of mercury, lead, and zinc in streambed sedimen

Separation and concentration of lower alcohols from dilute aqueous solutions

DOEpatents

Moore, Raymond H.; Eakin, David E.; Baker, Eddie G.; Hallen, Richard T.

1991-01-01

A process for producing, from a dilute aqueous solution of a lower (C.sub.1 -C.sub.5) alcohol, a concentrated liquid solution of the alcohol in an aromatic organic solvent is disclosed. Most of the water is removed from the dilute aqueous solution of alcohol by chilling sufficiently to form ice crystals. Simultaneously, the remaining liquid is extracted at substantially the same low temperature with a liquid organic solvent that is substantially immiscible in aqueous liquids and has an affinity for the alcohol at that temperature, causing the alcohol to transfer to the organic phase. After separating the organic liquid from the ice crystals, the organic liquid can be distilled to enrich the concentration of alcohol therein. Ethanol so separated from water and concentrated in an organic solvent such as toluene is useful as an anti-knock additive for gasoline.

Application of a Two-Dimensional Reservoir Water-Quality Model of Beaver Lake, Arkansas, for the Evaluation of Simulated Changes in Input Water Quality, 2001-2003

USGS Publications Warehouse

Galloway, Joel M.; Green, W. Reed

2007-01-01

Beaver Lake is considered a primary watershed of concern in the State of Arkansas. As such, information is needed to assess water quality, especially nutrient enrichment, nutrient-algal relations, turbidity, and sediment issues within the system. A previously calibrated two-dimensional, laterally averaged model of hydrodynamics and water quality was used for the evaluation of changes in input nutrient and sediment concentrations on the water quality of the reservoir for the period of April 2001 to April 2003. Nitrogen and phosphorus concentrations were increased and decreased and tested independently and simultaneously to examine the nutrient concentrations and algal response in the reservoir. Suspended-solids concentrations were increased and decreased to identify how solids are distributed in the reservoir, which can contribute to decreased water clarity. The Beaver Lake model also was evaluated using a conservative tracer. A conservative tracer was applied at various locations in the reservoir model to observe the fate and transport and how the reservoir might react to the introduction of a conservative substance, or a worst-case spill scenario. In particular, tracer concentrations were evaluated at the locations of the four public water-supply intakes in Beaver Lake. Nutrient concentrations in Beaver Lake increased proportionally with increases in loads from the three main tributaries. An increase of 10 times the calibrated daily input nitrogen and phosphorus in the three main tributaries resulted in daily mean total nitrogen concentrations in the epilimnion that were nearly 4 times greater than the calibration concentrations at site L2 and more than 2 times greater than the calibrated concentrations at site L5. Increases in daily input nitrogen in the three main tributaries independently did not correspond in substantial increases in concentrations of nitrogen in Beaver Lake. The greatest proportional increase in phosphorus occurred in the epilimnion at sites L3 and L4 and the least increase occurred at sites L2 and L5 when calibrated daily input phosphorus concentrations were increased. When orthophosphorus was increased in all three tributaries simultaneously by a factor of 10, daily mean orthophosphorus concentrations in the epilimnion of the reservoir were almost 11 times greater than the calibrated concentrations at sites L2 and L5, and 15 times greater in the epilimnion of the reservoir at sites L3 and L4. Phosphorus concentrations in Beaver Lake increased less when nitrogen and phosphorus were increased simultaneously than when phosphorus was increased independently. The greatest simulated increase in algal biomass (represented as chlorophyll a) occurred when nitrogen and phosphorus were increased simultaneously in the three main tributaries. On average, the chlorophyll a values only increased less than 1 microgram per liter when concentrations of nitrogen or phosphorous were increased independently by a factor of 10 at all three tributaries. In comparison, when nitrogen and phosphorus were increased simultaneously by a factor of 10 for all three tributaries, the chlorophyll a concentration increased by about 10 micrograms per liter on average, with a maximum increase of about 57 micrograms per liter in the epilimnion at site L3 in Beaver Lake. Changes in algal biomass with changes in input nitrogen and phosphorus were variable through time in the Beaver Lake model from April 2001 to April 2003. When calibrated daily input nitrogen and phosphorus concentrations were increased simultaneously for the three main tributaries, the increase in chlorophyll a concentration was the greatest in late spring and summer of 2002. Changes in calibrated daily input inorganic suspended solids concentrations were examined because of the effect they may have on water clarity in Beaver Lake. The increase in total suspended solids was greatest in the hypolimnion at the upstream end of Beaver Lake, and negligible changes

Quantification of changes in metal loading from storm runoff, Merse River (Tuscany, Italy)

USGS Publications Warehouse

Kimball, B.A.; Bianchi, F.; Walton-Day, K.; Runkel, R.L.; Nannucci, M.; Salvadori, A.

2007-01-01

The Merse River in Tuscany is affected by mine drainage and the weathering of mine wastes along several kilometres of its catchment. The metal loading to the stream was quantified by defining detailed profiles of discharge and concentration, using tracer-dilution and synoptic-sampling techniques. During the course of a field experiment to evaluate metal loading to the Merse, such data were obtained for both storm and pre-storm conditions, providing a unique opportunity for comparison. Iron, Cu, and Mn were chosen to illustrate changes resulting from the storm. The total-recoverable load of Fe increased 21-fold, while loads of Cu and Mn increased by 8- and 7-fold, respectively, during the storm runoff. The increases most likely resulted from flushing particulates from near the stream, resuspension of colloidal material from the streambed, and increased ground-water inflow to the stream. The increases in Cu and Mn loads results from their association with colloids. It is possible that in-stream colloids had relatively more Cu than Mn, while near-stream colloids had relatively more Mn. Each of the metals also increased as a result of increased ground-water discharge during the storm. Despite great increases in load, the filterable concentrations of these metals did not increase substantially, remaining below chronic levels of toxicity. ?? 2007 Springer-Verlag.

HTO and OBT concentrations in a wetland ecosystem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, S. B.; Workman, W. J. G.; Davis, P. A.

2008-07-15

Tritiated water (HTO) and organically bound tritium (OBT) concentrations in the non-human biota inhabiting Duke Swamp were measured during the 2005 growing season. Samples of surface water, soil, plants, precipitation, wild animals and air moisture were collected from 2005 May to October at five locations in the swamp and analyzed for their tritium content. HTO concentrations in air moisture decreased with height since the tritium source is in the ground. Soil HTO concentrations were not closely related to the concentrations in nearby surface water and the HTO concentration in balsam fir needles showed no clear pattern with height. HTO concentrationsmore » in moss, grass and alder leaves decreased in September, which is the time when metabolic activity is reduced. OBT concentrations in a given compartment showed less variation than the HTO concentrations in that compartment. The OBT/HTO ratio was approximately one for soil and less than one for plants, with the exception of lichen. The OBT/HTO ratio in most wild animals was also less than one, but increased to more than 2.0 for mice. Although the tritium concentrations varied substantially in space and time in Duke Swamp, the fact that OBT/HTO <1 for most compartments suggests that equilibrium conditions hold locally. (authors)« less

Degradation of polycyclic aromatic hydrocarbons (PAHs) present in used motor oil and implications for urban runoff quality

NASA Astrophysics Data System (ADS)

Ferreira, M.; Stenstrom, M. K.; Lau, S.

2013-12-01

Polycyclic aromatic hydrocarbons (PAHs) are common organic pollutants of urban stormwater runoff due to atmospheric deposition, vehicle-related discharges, and coal tar pavement sealants. The US EPA lists sixteen PAHs as priority pollutants and seven of those are potential carcinogenic compounds. Due to their molecular structure, PAHs tend to attach to particles that will subsequently be deposited as sediments in waterways. This study focuses on the degradation of PAHs present in used motor oil. Four experimental setups were used to simulate volatilization and photooxidation in the degradation of sixteen PAHs as observed for up to 54 days. The volatilization-only experiment showed substantial reduction only in the concentration of Napthalene (Nap). However, photooxidation-only was more efficient in degrading PAHs. In this process, substantial reduction in the concentrations of Nap, Acenapthene (Anthe), Anthracene (ANT), Fluoranthene (FLT), Pyrene (PYR), Benz[a]anthracene (BaA), Benzo[a]pyrene (BaP), Indeno[1,2,3,cd]pyrene (INP), and Benz[g,h,i]perylene (BghiP) were observed as early as five days. The two volatilization-photooxidation experiments exhibited substantial reduction in the concentrations of Fluorene (FLU), Chrysene (CHR) and Benzo[b]fluoranthene (BbF), in addition to the PAHs reduced by photooxidation-only. Phenanthrene (PHE), Fluoranthene (FLT), and Benzo[b]fluoranthene (BbF) only exhibited substantial decreased concentrations after 20 days in the volatilization-photooxidation experiment. One PAH, acenapthylene (Anthy), was not detected in the original sample of used motor oil. The highest degradations were observed in the combined volatilization-photooxidation experiment. In regions with infrequent rainfall, such as Southern California, molecules of PAHs attached to highway particles will have time to undergo degradation prior to transport. Therefore, PAHs may be present in lower concentrations in highway runoff in dry climates than in rainy climates. To support this hypothesis, a review of highway-related PAHs concentrations is presented.

Effects of snowmobile use on snowpack chemistry in Yellowstone National Park, 1998

USGS Publications Warehouse

Ingersoll, George P.

1999-01-01

Snowmobile use in Yellowstone National Park has increased substantially in the past three decades. In areas of greatest snowmobile use, elevated levels of by-products of gasoline combustion such as ammonium and benzene have been detected in snowpack samples. Annual snowpacks and snow-covered roadways trap deposition from local and regional atmospheric emissions. Snowpack samples representing most of the winter precipitation were collected at about the time of maximum annual snow accumulation at a variety of locations in the park to observe effects of a range of snowmobile traffic levels. Concentrations of organic and inorganic compounds in snow samples from pairs of sites located directly in and off snow-packed roadways used by snowmobiles were compared to concentrations in samples collected at nearby off-road sites. Concentrations of ammonium were 2 to 5 times higher for the in-road snow compared to off-road snow for each pair of sites. Thus, concentrations decreased rapidly with distance from roadways. In addition, concentrations of ammonium, nitrate, sulfate, benzene, and toluene in snow were positively correlated with snowmobile use.

Dioxin concentrations in dietary supplements containing animal oil on the Japanese market between 2007 and 2014.

PubMed

Tsutsumi, Tomoaki; Takatsuki, Satoshi; Teshima, Reiko; Matsuda, Rieko; Watanabe, Takahiro; Akiyama, Hiroshi

2018-01-01

We determined the concentrations of dioxins (polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls) in 46 dietary supplement products, containing the oil of fish, marine mammals, or egg yolk, on the Japanese market between 2007 and 2014. Dioxins were detected in 43 of the 46 products tested at concentrations from 0.00015 to 67 pg TEQ/g. The highest concentration of dioxins was found in a shark liver oil product which varied insignificantly in five batches collected over a two-year period. The dioxin intakes from these five batches reached 2.3-2.8 pg TEQ/kg bw/day, or 58%-70%, respectively, of the Japanese tolerable daily intake (TDI) of 4 pg TEQ/kg bw/day. However, the dioxin intakes from most of the other products tested were less than 5% of the TDI. Although rare, supplements based on animal oils may contain relatively high concentrations of dioxins, leading to a substantial increase in dioxin intakes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Role of volatilization in changing TBA and MTBE concentrations at MTBE-contaminated sites.

PubMed

Eweis, Juana B; Labolle, Eric M; Benson, David A; Fogg, Graham E

2007-10-01

Tertiary butyl alcohol (TBA) is commonly found as an impurity in methyl tertiary butyl ether (MTBE) added to gasoline. Frequent observations of high TBA, and especially rising TBA/MTBE concentration ratios, in groundwater at gasoline spill sites are generally attributed to microbial conversion of MTBE to TBA. Typically overlooked is the role of volatilization in the attenuation of these chemicals especially in the vadose zone, which is a source of contamination to groundwater. Here we show that volatilization, particularly through remediation by vapor extraction, can substantially affect the trends in TBA and MTBE concentrations and the respective mass available to impact groundwater aquifers, through the preferential removal of more volatile compounds, including MTBE, and the apparent enrichment of less volatile compounds like TBA. We demonstrate this phenomenon through numerical simulations of remedial-enhanced volatilization. Results show increases in TBA/MTBE concentration ratios consistent with ratios observed in groundwater at gasoline spill sites. Volatilization is an important, and potentially dominant, process that can result in concentration trends similar to those typically attributed to biodegradation.

Pulmonary artery smooth muscle cell [Ca2+]i and contraction: responses to diphenyleneiodonium and hypoxia.

PubMed

Zhang, F; Carson, R C; Zhang, H; Gibson, G; Thomas, H M

1997-09-01

To investigate mechanisms of inhibition of hypoxic pulmonary vasoconstriction (HPV), we studied pulmonary artery smooth muscle cell (PASMC) responses to hypoxia, utilizing diphenyleneiodonium (DPI), which blocks HPV. We measured cell contraction in primary cultures of rat PASMC grown on collagen gels and cytosolic free Ca2+ concentration ([Ca2+]i) in PASMC grown on glass. DPI (5 and 20 microM) caused contraction of PASMC and increased [Ca2+]i. Omission of extracellular Ca2+ diminished the DPI-induced PASMC contraction and greatly reduced the increase in [Ca2+]i. DPI substantially inhibited KCl-induced PASMC contraction (1 microM DPI) and the increase in [Ca2+]i (5 microM DPI). Severe hypoxia contracted PASMC and quadrupled [Ca2+]i. DPI, 1 microM, substantially inhibited hypoxic contraction, but neither 1 nor 5 microM DPI diminished the hypoxia-induced increase in [Ca2+]i, which was greatly attenuated by 20 microM DPI. These data show 1) that DPI increases [Ca2+]i, accounting for DPI-induced PASMC contraction and 2) that 1 and 5 microM DPI inhibit the hypoxia-induced contraction but not the hypoxia-induced increase in [Ca2+]i, suggesting that DPI inhibits hypoxic PASMC contraction downstream of the Ca2+ signal by desensitizing the contractile apparatus and indicating a potential control point for modulation of HPV.

Changes in nitrate concentrations and loads in United Kingdom watersheds since 1868: Evidence for land use change as a dominant driver and ineffective mitigation

NASA Astrophysics Data System (ADS)

Whelan, M. J.; Burt, T. P.; Howden, N. K.; Worrall, F.

2012-12-01

Nitrate concentrations and fluxes in many of the world's rivers have increased over the latter part of the 20th Century leading to freshwater and, more frequently, marine eutrophication. This has largely been linked to agricultural intensification which has increased food production via a combination of improved methods, crop varieties, pest control technologies, mechanisation and fertiliser use. The area of land under intensive production has also increased in many watersheds. Here we analyse long term water quality records from a number of UK rivers to assess temporal patterns of nitrate concentrations and fluxes and to identify driving factors. The data, which include the world's longest record of nitrate concentrations from the River Thames, London (1868 to 2008), show that dramatic and sustained increases in nitrate concentrations and fluxes occurred after periods of substantial land use change including the conversion of significant areas of permanent pasture to arable production in the 1940s and 1960s and increases in fertiliser use in the 1960s. Grassland to arable conversion can release large quantities of nitrate due to the enhanced mineralisation of the extra soil organic nitrogen which accumulates in pasture systems. Recent attempts to reverse these increases, such as widespread restrictions of nitrogen inputs have, thus far, been relatively ineffective, although there have been recent indications that levels have stabilised in some watersheds. Our analysis clearly shows the dominance of land use change over other potential drivers such as waste water emission, climatic and hydrological changes and suggests that current measures for the mitigation of large-scale diffuse pollution based on limiting fertiliser use are not drastic enough to reverse significantly the increases in riverine nitrate concentrations which have been observed. Analysis of the long term data also shows that trend detection is problematic for periods less than about 15 years, without a longer term historical context. The data and associated analysis support the continued maintenance of very long benchmark monitoring sites to identify trends and adequately assess the drivers of environmental change. Nitrate concentrations measured in the river Thames since 1868 showing drammatic increases in the latter half of the 20th century. Red line shows annual average concentration.

Hydrogeologic factors that affect the flowpath of water in selected zones of the Edwards Aquifer, San Antonio region, Texas

USGS Publications Warehouse

Groschen, G.E.

1996-01-01

The Edwards aquifer in the San Antonio region supplies drinking water for more than 1 million people. Proper development and protection of the aquifer is a high priority for local and State authorities. To better understand the flow of water in two major flowpaths in the Edwards aquifer, stratigraphic, structural, hydrologic, and geochemical data were analyzed. The western Medina flowpath is in parts of Uvalde, Medina, and Bexar Counties, and the eastern flowpath is in northern Bexar and central Comal Counties. A major hydrogeologic factor that affects the pattern of flow in the Edwards aquifer is the spatial and temporal distribution of recharge. Other hydrogeologic factors that affect flowpaths include internal boundaries and the location and rate of spring discharge. The relative displacement of faults and the high permeability layers have substantial control on the discharge at springs and on the flowpaths in the Edwards aquifer. Analysis of the estimated recharge to the Edwards aquifer during 1982 89 indicated that during years of substantial precipitation, a large part of the net recharge probably is diffuse infiltration of precipitation over large parts of the recharge area. During years with below-normal precipitation, most recharge is leakage from rivers and streams that drain the catchment subbasins. In the western Medina flowpath, concentrations of major ions indicate saturation of calcite and undersaturation of dolomite the two minerals that constitute most of the Edwards aquifer matrix. Concentrations of dissolved calcium, alkalinity, and dissolved chloride in the eastern flowpath are greater than those in the western Medina flowpath. These upward trends in concentrations might result in part from: (1) increased development in the recharge area, (2) mineralized effluent from developed areas, or (3) increased dissolution of aquifer material. Tritium data from wells sampled in and near the western Medina flowpath indicate no vertical stratification of flow. Tritium concentrations in the recharge area of the western Medina flowpath are smaller than would be expected from previous studies and for the amount of recharge the area presumably received since 1952. Stable-isotopic data indicate that the water in the Edwards aquifer is meteoric and, except in one known area, has not been subjected to substantial evaporation or other isotope-fractionating processes. Evaporation of water from Medina Lake results in a heavier stable-isotopic ratio in lake water, which subsequently recharges the Edwards aquifer. The stable-isotopic data indicate that lake water does not enter either of the two flowpaths.

Removal of natural organic matter in drinking water treatment by coagulation: A comprehensive review.

PubMed

Sillanpää, Mika; Ncibi, Mohamed Chaker; Matilainen, Anu; Vepsäläinen, Mikko

2018-01-01

Natural organic matter (NOM) is a complex matrix of organic substances produced in (or channeled to) aquatic ecosystems via various biological, geological and hydrological cycles. Such variability is posing a serious challenge to most water treatment technologies, especially the ones designed to treat drinking water supplies. Lately, in addition to the fluctuating composition of NOM, a substantial increase of its concentration in fresh waters, and also municipal wastewater effluents, has been reported worldwide, which justifies the urgent need to develop highly efficient and versatile water treatment processes. Coagulation is among the most applied processes for water and wastewater treatment. The application of coagulation to remove NOM from drinking water supplies has received a great deal of attention from researchers around the world because it was efficient and helped avoiding the formation of disinfection by products (DBPs). Nonetheless, with the increased fluctuation of NOM in water (concentration and composition), the efficiency of conventional coagulation was substantially reduced, hence the need to develop enhanced coagulation processes by optimizing the operating conditions (mainly the amount coagulants and pH), developing more efficient inorganic or organic coagulants, as well as coupling coagulation with other water treatment technologies. In the present review, recent research studies dealing with the application of coagulation for NOM removal from drinking water supplies are presented and compared. In addition, integration schemes combining coagulation and other water treatment processes are presented, including membrane filtration, oxidation, adsorption and others processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of photopolymerizable clay nanocomposites utilizing reactive dispersants

NASA Astrophysics Data System (ADS)

Owusu-Adom, Kwame

Nanocomposites hold tremendous promise for expanding the utility of polymeric materials. However, accessing particulate sizes in the nanoscale domain continues to be a scientific challenge, especially in highly cross-linked photopolymerizable systems. In this study, photopolymerizable nanocomposites utilizing clay nanoparticles and reactive dispersants have been developed. The influence of particle size, dispersant-clay interactions, and surfactant concentration on photopolymerization behavior and nanoparticle dispersion has been elucidated. Clay particles serve as templates upon which surfactants aggregate during photopolymerization. This results in higher photopolymerization rates with addition of increasing concentrations of polymerizable surfactants. Furthermore, polymerizable surfactants induce faster photopolymerization rates compared to non-polymerizable analogues in systems that have ionically-bound dispersants on the particle surface. Utilizing reactive organoclays induces significant changes to the photopolymerization behavior depending on the choice of reactive functionality employed. Faster acrylate photopolymerization rates occur in photopolymer systems containing thiol-modified clays, while much slower rates occur for nonpolymerizable organoclay systems. In addition, chemical compatibility between monomer and clay dispersant (based on chemical similarity or polarity) allows enhancement of exfoliation in photopolymerizable formulations. With polymerizable dispersants, exfoliation is readily achieved in various multifunctional acrylate systems. The degree of exfoliation depends on the position of the reactive group relative to the surfactant's cationic site and the type of functionality. Thiolated organoclays exfoliate during polymerization, while methacrylated clays show substantially less dependence on polymerization behavior. Interestingly, changes in the physical properties of the resulting nanocomposite are independent of the degree of exfoliation in polymerizable organoclay systems. The polymer cross-link density dictates the magnitude of change in both modulus and glass transition temperature of the nanocomposite. Substantial increases in modulus and Tg occur in elastomeric and low cross-link density polymers, while decreases occur in the modulus and Tg of highly cross-linked polymer networks. Finally, these parameters have formed a basis for developing nanocomposites with higher moduli and lower volumetric shrinkage. The photopolymerization rates of these systems are controllable and increase substantially with addition of polymerizable organoclays. Such properties occur in traditional multifunctional acrylate photopolymer systems as well as new binary thiol-(meth)acrylate and ternary thiol-ene-(meth)acrylate photopolymers.

High-resolution satellite remote sensing of provincial PM2.5 trends in China from 2001 to 2015

NASA Astrophysics Data System (ADS)

Lin, C. Q.; Liu, G.; Lau, A. K. H.; Li, Y.; Li, C. C.; Fung, J. C. H.; Lao, X. Q.

2018-05-01

Given the vast territory of China, the long-term PM2.5 trends may substantially differ among the provinces. In this study, we aim to assess the provincial PM2.5 trends in China during the past few Five-Year Plan (FYP) periods. The lack of long-term PM2.5 measurements, however, makes such assessment difficult. Satellite remote sensing of PM2.5 concentration is an important step toward filling this data gap. In this study, a PM2.5 data set was built over China at a resolution of 1 km from 2001 to 2015 using satellite remote sensing. Analyses show that the national average of PM2.5 concentration increased by 0.04 μg·m-3·yr-1 during the 10th FYP period (2001-2005) and started to decline by -0.65 μg·m-3·yr-1 and -2.33 μg·m-3·yr-1 during the 11th (2006-2010) and the 12th (2011-2015) FYP period, respectively. In addition, substantial differences in the PM2.5 trends were observed among the provinces. Provinces in the Beijing-Tianjin-Hebei (BTH) region had the largest reduction of PM2.5 concentrations during the 10th and 12th FYP period. The greatest reduction rate of PM2.5 concentration during the 10th and 12th FYP period was observed in Beijing (-3.68 μg·m-3·yr-1) and Tianjin (-6.62 μg·m-3·yr-1), respectively. In contrast, PM2.5 concentrations remained steady for provinces in eastern and southeastern China (e.g., Shanghai) during the 12th FYP period. In overall, great efforts are still required to effectively reduce the PM2.5 concentrations in future.

Enhanced micropollutant biodegradation and assessment of nitrous oxide concentration reduction in wastewater treated by acclimatized sludge bioaugmentation.

PubMed

Boonnorat, Jarungwit; Techkarnjanaruk, Somkiet; Honda, Ryo; Ghimire, Anish; Angthong, Sivakorn; Rojviroon, Thammasak; Phanwilai, Supaporn

2018-05-11

This research investigated the micropollutant biodegradation and nitrous oxide (N 2 O) concentration reduction in high strength wastewater treated by two-stage activated sludge (AS) systems with (bioaugmented) and without (non-bioaugmented) acclimatized sludge bioaugmentation. The bioaugmented and non-bioaugmented systems were operated in parallel for 228 days, with three levels of concentrations of organics, nitrogen, and micropollutants in the influent: conditions 1 (low), 2 (moderate), and 3 (high). The results showed that, under condition 1, both systems efficiently removed the organic and nitrogen compounds. However, the bioaugmented system was more effective in the micropollutant biodegradation and N 2 O concentration reduction than the non-bioaugmented one. Under condition 2, the nitrogen and micropollutant biodegradation efficiency of the non-bioaugmented system slightly decreased, while the N 2 O concentration declined in the bioaugmented system. Under condition 3, the treatment performance and N 2 O concentration abatement were substantially lowered as the compounds concentration increased. Further analysis also showed that the acclimatized sludge bioaugmentation increased the bacterial diversity in the system. In essence, the acclimatized sludge bioaugmentation strategy was highly effective for the influent with low compounds concentration, achieving the organics and nitrogen removal efficiencies of 92-97%, relative to 71-97% of the non-bioaugmented system. The micropollutant treatment efficiency of the bioaugmented system under condition 1 was 75-92%, indicating significant improvement in the treatment performance (p < 0.05), compared with 60-79% of the non-bioaugmented system. Copyright © 2018 Elsevier B.V. All rights reserved.

Brief Exposures to the Taste of Ethanol (EtOH) and Quinine Promote Subsequent Acceptance of EtOH in a Paradigm that Minimizes Postingestive Consequences.

PubMed

Loney, Gregory C; Meyer, Paul J

2018-03-01

Aversion to the orosensory properties of concentrated ethanol (EtOH) solutions is often cited as a primary barrier to initiation of drinking and may contribute to abstention. These aversive properties include gustatory processes which encompass both bitter-like taste qualities and trigeminal-mediated irritation. Chronic intermittent EtOH access (CIA) results in substantial and persistent increases in EtOH consumption, but the degree to which this facilitation involves sensory responding to EtOH and other bitter stimuli is currently undetermined. Long-Evans rats were given brief-access licking tests designed to examine the immediate, taste-guided assessment of the palatability of EtOH and quinine solutions. Rats were assessed once in a naïve state and again following previous brief-access exposure, or following 4 weeks of CIA. The relationship between the sensitivity to the aversive orosensory properties of EtOH and quinine following EtOH access and the impact of antecedent quinine exposure on the acceptance of EtOH were determined in 2 parallel studies. Both brief access to EtOH and 4-week CIA resulted in substantial rightward shifts in the concentration-response function of brief-access EtOH licking, indicating that EtOH exposure increased acceptance of the taste of EtOH. The initial sensitivity to the aversive orosensory properties of EtOH and quinine was positively correlated in naïve rats, such that rats that were initially more accepting of quinine were also more accepting of EtOH. Rats that sampled quinine immediately prior to tasting EtOH exhibited successive positive contrast in that they were more accepting of highly concentrated EtOH, relative to a water-control group. Increased EtOH acceptance following exposure is, at least in part, facilitated by a decrease in its aversive sensory properties. Both long- and short-term access increase the palatability of the taste of EtOH in brief-access licking tests. Moreover, the sensitivity to the bitterness of quinine was predictive of acceptance of EtOH indicating some commonality in the sensory mechanisms that mediate the initial acceptance of the 2 stimuli. Accordingly, immediate prior exposure to quinine results in increased acceptance of EtOH, suggesting that successive positive contrast between oral stimuli may contribute to increased alcohol consumption. Copyright © 2017 by the Research Society on Alcoholism.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of gasoline oxygenates, selected degradates, and BTEX in water by heated purge and trap/gas chromatography/mass spectrometry

USGS Publications Warehouse

Rose, Donna L.; Sandstrom, Mark W.

2003-01-01

Devils Lake rose dramatically during the 1990's, causing extensive flood damages. Because of the potential for continued flooding, the U.S. Army Corps of Engineers has been conducting studies to evaluate the feasibility of constructing and operating an outlet from Devils Lake. The occurrence of mercury in lakes, wetlands, and rivers and the potential for increased loading of mercury into the Sheyenne River as a result of a Devils Lake outlet needed to be evaluated as part of the studies. Sixteen lake, wetland, and river sites in the Devils Lake, Sheyenne River, Red River of the North, and Red Lake River Basins were sampled and analyzed for mercury constituents and other selected properties and constituents relevant to mercury aquatic chemistry. For the lake and wetland sites, whole-water methylmercury concentrations ranged from less than 0.04 to 3.53 nanograms per liter and whole-water total mercury concentrations ranged from 0.38 to 7.02 nanograms per liter. Conditions favorable for methylation of mercury generally exist at the lake and wetland sites, as indicated by larger dissolved methylmercury concentrations in near-bottom samples than in near-surface samples and by relatively large ratios of methylmercury to total mercury (generally greater than 10 percent for the summer sampling period). Total mercury concentrations were larger for the summer sampling period than for the winter sampling period for all lake and wetland sites. A wetland site in the upper Devils Lake Basin had the largest mercury concentrations for the lake and wetland sites. For the river sites, whole-water methylmercury concentrations ranged from 0.15 to 1.13 nanograms per liter and whole-water total mercury concentrations ranged from 2.00 to 26.90 nanograms per liter. Most of the mercury for the river sites occurred in particulate inorganic phase. Summer ratios of whole-water methylmercury to whole-water total mercury were 35 percent for Starkweather Coulee (a wetland-dominated site), near or less than 10 percent for the Sheyenne River sites, and less than 8 percent for the Red River of the North and Red Lake River sites. Although the number of samples collected during this investigation is small, results indicated an outlet from Devils Lake probably would not have adverse effects on mercury concentrations in the Sheyenne River upstream from Lake Ashtabula. However, because discharges in the Sheyenne River would increase during some periods, loads of mercury entering Lake Ashtabula also would increase. Lake Ashtabula probably serves as a sink for suspended sediment and mercury. Thus, a Devils Lake outlet probably would not have substantial effects on mercury concentrations and loads in the downstream part of the Sheyenne River or in the Red River of the North. More substantial effects could occur for Lake Ashtabula.

Reconnaissance of mercury in lakes, wetlands, and rivers in the Red River of the North Basin, North Dakota, March through August 2001

USGS Publications Warehouse

Sando, Steven K.; Wiche, G.J.; Lundgren, R.F.; Sether, Bradley A.

2003-01-01

Devils Lake rose dramatically during the 1990's, causing extensive flood damages. Because of the potential for continued flooding, the U.S. Army Corps of Engineers has been conducting studies to evaluate the feasibility of constructing and operating an outlet from Devils Lake. The occurrence of mercury in lakes, wetlands, and rivers and the potential for increased loading of mercury into the Sheyenne River as a result of a Devils Lake outlet needed to be evaluated as part of the studies.Sixteen lake, wetland, and river sites in the Devils Lake, Sheyenne River, Red River of the North, and Red Lake River Basins were sampled and analyzed for mercury constituents and other selected properties and constituents relevant to mercury aquatic chemistry. For the lake and wetland sites, whole-water methylmercury concentrations ranged from less than 0.04 to 3.53 nanograms per liter and whole-water total mercury concentrations ranged from 0.38 to 7.02 nanograms per liter. Conditions favorable for methylation of mercury generally exist at the lake and wetland sites, as indicated by larger dissolved methylmercury concentrations in near-bottom samples than in near-surface samples and by relatively large ratios of methylmercury to total mercury (generally greater than 10 percent for the summer sampling period). Total mercury concentrations were larger for the summer sampling period than for the winter sampling period for all lake and wetland sites. A wetland site in the upper Devils Lake Basin had the largest mercury concentrations for the lake and wetland sites.For the river sites, whole-water methylmercury concentrations ranged from 0.15 to 1.13 nanograms per liter and whole-water total mercury concentrations ranged from 2.00 to 26.90 nanograms per liter. Most of the mercury for the river sites occurred in particulate inorganic phase. Summer ratios of whole-water methylmercury to whole-water total mercury were 35 percent for Starkweather Coulee (a wetland-dominated site), near or less than 10 percent for the Sheyenne River sites, and less than 8 percent for the Red River of the North and Red Lake River sites.Although the number of samples collected during this investigation is small, results indicated an outlet from Devils Lake probably would not have adverse effects on mercury concentrations in the Sheyenne River upstream from Lake Ashtabula. However, because discharges in the Sheyenne River would increase during some periods, loads of mercury entering Lake Ashtabula also would increase. Lake Ashtabula probably serves as a sink for suspended sediment and mercury. Thus, a Devils Lake outlet probably would not have substantial effects on mercury concentrations and loads in the downstream part of the Sheyenne River or in the Red River of the North. More substantial effects could occur for Lake Ashtabula.

Influence of Ar addition on ozone generation in a non-thermal plasma—a numerical investigation

NASA Astrophysics Data System (ADS)

Chen, Hsin Liang; Lee, How Ming; Chen, Shiaw Huei; Wei, Ta Chin; Been Chang, Moo

2010-10-01

A numerical model based on a dielectric barrier discharge is developed in this study to investigate the influence of Ar addition on ozone generation. The simulation results show good agreement with the experimental data, confirming the validity of the numerical model. The mechanisms regarding how the Ar addition affects ozone generation are investigated with the assistance of a numerical simulation by probing into the following two questions, (1) why the ozone concentration just slightly decreases in the low specific input energy (SIE, the ratio of discharge power to gas flow rate) region even if the inlet O2 concentration is substantially decreased and (2) why the variation of the increased rate of ozone concentration with SIE (i.e. the variation in the slope of ozone concentration versus SIE) is more significant for an O2/Ar mixture plasma. As SIE is relatively low, ozone decomposition through electron-impact and radical attack reactions is less significant because of low ozone concentration and gas temperature. Therefore, the ozone concentration depends mainly on the amount of oxygen atoms generated. The simulation results indicate that the amount of oxygen atoms generated per electronvolt for Ar concentrations of 0%, 10%, 30%, 50% and 80% are 0.178, 0.174, 0.169, 0.165 and 0.166, respectively, explaining why the ozone concentration does not decrease linearly with the inlet O2 concentration in the low SIE region. On the other hand, the simulation results show that increasing Ar concentration would lead to a lower reduced field and a higher gas temperature. The former would lead to an increase in the rate constant of e + O3 → e + O + O2 while the latter would result in a decrease in the rate constant of O + O2 + M → O3 + M and an increase in that of O3 + O → 2O2. The changes in the rate constants of these reactions would have a negative effect on ozone generation, which is the rationale for the second question.

Cleanliness of Ti-bearing Al-killed ultra-low-carbon steel during different heating processes

NASA Astrophysics Data System (ADS)

Guo, Jian-long; Bao, Yan-ping; Wang, Min

2017-12-01

During the production of Ti-bearing Al-killed ultra-low-carbon (ULC) steel, two different heating processes were used when the converter tapping temperature or the molten steel temperature in the Ruhrstahl-Heraeus (RH) process was low: heating by Al addition during the RH decarburization process and final deoxidation at the end of the RH decarburization process (process-I), and increasing the oxygen content at the end of RH decarburization, heating and final deoxidation by one-time Al addition (process-II). Temperature increases of 10°C by different processes were studied; the results showed that the two heating processes could achieve the same heating effect. The T.[O] content in the slab and the refining process was better controlled by process-I than by process-II. Statistical analysis of inclusions showed that the numbers of inclusions in the slab obtained by process-I were substantially less than those in the slab obtained by process-II. For process-I, the Al2O3 inclusions produced by Al added to induce heating were substantially removed at the end of decarburization. The amounts of inclusions were substantially greater for process-II than for process-I at different refining stages because of the higher dissolved oxygen concentration in process-II. Industrial test results showed that process-I was more beneficial for improving the cleanliness of molten steel.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avtaeva, S. V., E-mail: s_avtaeva@mail.ru; Sosnin, E. A.; Saghi, B.

The influence of the chlorine concentration on the radiation efficiency of coaxial exciplex lamps (excilamps) excited by a dielectric barrier discharge (DBD) in binary Xe-Cl{sub 2} mixtures at pressures of 240–250 Torr is investigated experimentally and theoretically. The experiments were carried out at Cl{sub 2} concentrations in the range of 0.01–1%. The DBD characteristics were calculated in the framework of a one-dimensional hydrodynamic model at Cl{sub 2} concentrations in the range of 0.1–5%. It is found that the radiation intensities of the emission bands of Xe*{sub 2}(172 nm) and XeCl* (308 nm) are comparable when the chlorine concentration in themore » mixture is in the range of 0.01–0.1%. In this case, in the mixture, the radiation intensity of the Xe*{sub 2} molecule rapidly decreases with increasing Cl{sub 2} concentration and, at a chlorine concentration of ≥0.2%, the radiation of the B → X band of XeCl* molecules with a peak at 308 nm dominates in the discharge radiation. The radiation efficiency of this band reaches its maximum value at chlorine concentrations in the range of 0.4–0.5%. The calculated efficiencies of DBD radiation exceed those obtained experimentally. This is due to limitations of the one-dimensional model, which assumes the discharge to be uniform in the transverse direction, whereas the actual excilamp discharge is highly inhomogeneous. The influence of the chlorine concentration on the properties of the DBD plasma in binary Xe-Cl{sub 2} mixtures is studied numerically. It is shown that an increase in the Cl{sub 2} concentration in the mixture leads to the attachment of electrons to chlorine atoms and a decrease in the electron density and discharge conductivity. As a result, the electric field and the voltage drop across the discharge gap increase, which, in turn, leads to an increase in the average electron energy and the probability of dissociation of Cl{sub 2} molecules and ionization of Xe atoms and Cl{sub 2} molecules. The total energy deposited in the discharge rises with increasing chlorine concentration due to an increase in the power spent on the heating of positive and negative ions. The power dissipated by electrons decreases with increasing chlorine concentration in the working mixture. Recommendations on the choice of the chlorine content in the mixture for reducing the intensity of VUV radiation of the second continuum of the Xe*{sub 2} excimer without a substantial decrease in the excilamp efficiency are formulated.« less

Integrated multi-ISE arrays with improved sensitivity, accuracy and precision

NASA Astrophysics Data System (ADS)

Wang, Chunling; Yuan, Hongyan; Duan, Zhijuan; Xiao, Dan

2017-03-01

Increasing use of ion-selective electrodes (ISEs) in the biological and environmental fields has generated demand for high-sensitivity ISEs. However, improving the sensitivities of ISEs remains a challenge because of the limit of the Nernstian slope (59.2/n mV). Here, we present a universal ion detection method using an electronic integrated multi-electrode system (EIMES) that bypasses the Nernstian slope limit of 59.2/n mV, thereby enabling substantial enhancement of the sensitivity of ISEs. The results reveal that the response slope is greatly increased from 57.2 to 1711.3 mV, 57.3 to 564.7 mV and 57.7 to 576.2 mV by electronic integrated 30 Cl- electrodes, 10 F- electrodes and 10 glass pH electrodes, respectively. Thus, a tiny change in the ion concentration can be monitored, and correspondingly, the accuracy and precision are substantially improved. The EIMES is suited for all types of potentiometric sensors and may pave the way for monitoring of various ions with high accuracy and precision because of its high sensitivity.

Seasonal and diel variation in xylem CO2 concentration and sap pH in sub-Mediterranean oak stems.

PubMed

Salomón, Roberto; Valbuena-Carabaña, María; Teskey, Robert; McGuire, Mary Anne; Aubrey, Doug; González-Doncel, Inés; Gil, Luis; Rodríguez-Calcerrada, Jesús

2016-04-01

Since a substantial portion of respired CO2 remains within the stem, diel and seasonal trends in stem CO2 concentration ([CO2]) are of major interest in plant respiration and carbon budget research. However, continuous long-term stem [CO2] studies are scarce, and generally absent in Mediterranean climates. In this study, stem [CO2] was monitored every 15min together with stem and air temperature, sap flow, and soil water storage during a growing season in 16 stems of Quercus pyrenaica to elucidate the main drivers of stem [CO2] at different temporal scales. Fluctuations in sap pH were also assessed during two growing seasons to evaluate potential errors in estimates of the concentration of CO2 dissolved in xylem sap ([CO2*]) calculated using Henry's law. Stem temperature was the best predictor of stem [CO2] and explained more than 90% and 50% of the variability in stem [CO2] at diel and seasonal scales, respectively. Under dry conditions, soil water storage was the main driver of stem [CO2]. Likewise, the first rains after summer drought caused intense stem [CO2] pulses, suggesting enhanced stem and root respiration and increased resistance to radial CO2 diffusion. Sap flow played a secondary role in controlling stem [CO2] variations. We observed night-time sap pH acidification and progressive seasonal alkalinization. Thus, if the annual mean value of sap pH (measured at midday) was assumed to be constant, night-time sap [CO2*] was substantially overestimated (40%), and spring and autumn sap [CO2*] were misestimated by 25%. This work highlights that diel and seasonal variations in temperature, tree water availability, and sap pH substantially affect xylem [CO2] and sap [CO2*]. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Pronounced chemical response of Subarctic lakes to climate-driven losses in surface area

USGS Publications Warehouse

Lewis, Tyler L.; Lindberg, Mark S.; Schmutz, Joel A.; Heglund, Patricia J.; Rover, Jennifer R.; Koch, Joshua C.; Bertram, Mark R.

2015-01-01

Losses in lake area have been observed for several Arctic and Subarctic regions in recent decades, with unknown consequences for lake ecosystems. These reductions are primarily attributed to two climate-sensitive mechanisms, both of which may also cause changes in water chemistry: (i) increased imbalance of evaporation relative to inflow, whereby increased evaporation and decreased inflow act to concentrate solutes into smaller volumes; and (ii) accelerated permafrost degradation, which enhances sublacustrine drainage while simultaneously leaching previously frozen solutes into lakes. We documented changes in nutrients [total nitrogen (TN), total phosphorus (TP)] and ions (calcium, chloride, magnesium, sodium) over a 25 year interval in shrinking, stable, and expanding Subarctic lakes of the Yukon Flats, Alaska. Concentrations of all six solutes increased in shrinking lakes from 1985–1989 to 2010–2012, while simultaneously undergoing little change in stable or expanding lakes. This created a present-day pattern, much weaker or absent in the 1980s, in which shrinking lakes had higher solute concentrations than their stable or expanding counterparts. An imbalanced evaporation-to-inflow ratio (E/I) was the most likely mechanism behind such changes; all four ions, which behave semiconservatively and are prone to evapoconcentration, increased in shrinking lakes and, along with TN and TP, were positively related to isotopically derived E/I estimates. Moreover, the most conservative ion, chloride, increased >500% in shrinking lakes. Conversely, only TP concentration was related to probability of permafrost presence, being highest at intermediate probabilities. Overall, the substantial increases of nutrients (TN >200%, TP >100%) and ions (>100%) may shift shrinking lakes towards overly eutrophic or saline states, with potentially severe consequences for ecosystems of northern lakes.

Aerosols emitted in underground mine air by diesel engine fueled with biodiesel.

PubMed

Bugarski, Aleksandar D; Cauda, Emanuele G; Janisko, Samuel J; Hummer, Jon A; Patts, Larry D

2010-02-01

Using biodiesel in place of petroleum diesel is considered by several underground metal and nonmetal mine operators to be a viable strategy for reducing the exposure of miners to diesel particulate matter. This study was conducted in an underground experimental mine to evaluate the effects of soy methyl ester biodiesel on the concentrations and size distributions of diesel aerosols and nitric oxides in mine air. The objective was to compare the effects of neat and blended biodiesel fuels with those of ultralow sulfur petroleum diesel. The evaluation was performed using a mechanically controlled, naturally aspirated diesel engine equipped with a muffler and a diesel oxidation catalyst. The effects of biodiesel fuels on size distributions and number and total aerosol mass concentrations were found to be strongly dependent on engine operating conditions. When fueled with biodiesel fuels, the engine contributed less to elemental carbon concentrations for all engine operating modes and exhaust configurations. The substantial increases in number concentrations and fraction of organic carbon (OC) in total carbon over the baseline were observed when the engine was fueled with biodiesel fuels and operated at light-load operating conditions. Size distributions for all test conditions were found to be single modal and strongly affected by engine operating conditions, fuel type, and exhaust configuration. The peak and total number concentrations as well as median diameter decreased with an increase in the fraction of biodiesel in the fuels, particularly for high-load operating conditions. The effects of the diesel oxidation catalyst, commonly deployed to counteract the potential increase in OC emissions due to use of biodiesel, were found to vary depending upon fuel formulation and engine operating conditions. The catalyst was relatively effective in reducing aerosol number and mass concentrations, particularly at light-load conditions, but also showed the potential for an increase in nitrogen dioxide concentrations at high-load modes.

Impact of the 1993 flood on the distribution of organic contaminants in bed sediments of the Upper Mississippi River

USGS Publications Warehouse

Barber, L.B.; Writer, J.H.

1998-01-01

The 1500 km Upper Mississippi River (UMR) consists of 29 navigation pools and can be divided into the upper reach (pools 1-4), the middle reach (pools 5-13), and the lower reach (pools 14-26). Comparison of composite bed sediment samples collected from the downstream third of 24 pools before and after the 1993 UMR flood provides fieldscale data on the effect of the flood on sediment organic compound distributions. The sediments were analyzed for organic carbon, coprostanol, polynuclear aromatic hydrocarbons including pyrene, linear alkylbenzene-sulfonates, polychlorinated biphenyls (PCBs), and organochlorine pesticides. Most of the target compounds were detected in all of the sediment samples, although concentrations were generally <1 mg/kg. The highest concentrations typically occurred in the upper reach, an urbanized area on a relatively small river. Pool 4 (Lake Pepin) is an efficient sediment trap, and concentrations of the compounds below pool 4 were substantially lower than those in pools 2-4. Differences in concentrations before and after the 1993 flood also were greatest in the upper reach. In pools 1-4, concentrations of pyrene and PCBs decreased after the flood whereas coprostanol increased. These results suggest that bed sediments stored in the pools were diluted or buried by sediments with different organic compound compositions washed in from urban and agricultural portions of the watershed.The 1500 km Upper Mississippi River (UMR) consists of 29 navigation pools and can be divided into the upper reach (pools 1-4), the middle reach (pools 5-13), and the lower reach (pools 14-26). Comparison of composite bed sediment samples collected from the downstream third of 24 pools before and after the 1993 UMR flood provides field-scale data on the effect of the flood on sediment organic compound distributions. The sediments were analyzed for organic carbon, coprostanol, polynuclear aromatic hydrocarbons including pyrene, linear alkylbenzene-sulfonates, polychlorinated biphenyls (PCBs), and organochlorine pesticides. Most of the target compounds were detected in all of the sediment samples, although concentrations were generally <1 mg/kg. The highest concentrations typically occurred in the upper reach, an urbanized area on a relatively small river. Pool 4 (Lake Pepin) is an efficient sediment trap, and concentrations of the compounds below pool 4 were substantially lower than those in pools 2-4. Differences in concentrations before and after the 1993 flood also were greatest in the upper reach. In pools 1-4, concentrations of pyrene and PCBs decreased after the flood whereas coprostanol increased. These results suggest that bed sediments stored in the pools were diluted or buried by sediments with different organic compound compositions washed in from urban and agricultural portions of the watershed.

Oxidative stress, neurotoxicity, and metallothionein (MT) gene expression in juvenile rock fish Sebastes schlegelii under the different levels of dietary chromium (Cr(6+)) exposure.

PubMed

Kim, Jun-Hwan; Kang, Ju-Chan

2016-03-01

Juvenile Sebastes schlegelii were exposed for 4 weeks with the different levels of dietary chromium (Cr(6+)) concentration (0, 30, 60, 120 and 200mg/kg). The superoxide dismutase (SOD) activity, glutathione S-transferase (GST) activity, and glutathione (GSH) level of liver and gill were evaluated after 4 weeks exposure. The SOD and GST activity of liver and gill was significantly increased in the concentration of 240mg/kg after 2 weeks and over 120mg/kg after 4 weeks, whereas a considerable decrease in the concentration of 240mg/kg after 2 weeks and over 120mg/kg after 4 weeks was observed in the GSH levels of liver and gill. In neurotoxicity, AChE activity was significatly inhibited in brain in the concentration of 240mg/kg after 2 weeks and over 60mg/kg after 4 weeks and muscle in the concentration of 240mg/kg after 2 weeks and over 120mg/kg after 4 weeks. Metallothionein (MT) gene in liver was considerably increased over 120mg/kg after 2 weeks and at 30, 120, and 240mg/kg after 4 weeks by dietary chromium exposure. The results indicate that dietary Cr exposure over 120mg/kg can induce substantial alterations in antioxidant responses, AChE activity and MT gene expression. Copyright © 2015 Elsevier Inc. All rights reserved.

Current use of factor concentrates in pediatric cardiac anesthesia.

PubMed

Guzzetta, Nina A; Williams, Glyn D

2017-07-01

Excessive bleeding following pediatric cardiopulmonary bypass is associated with increased morbidity and mortality, both from the effects of hemorrhage and the therapies employed to achieve hemostasis. Neonates and infants are especially at risk because their coagulation systems are immature, surgeries are often complex, and cardiopulmonary bypass technologies are inappropriately matched to patient size and physiology. Consequently, these young children receive substantial amounts of adult-derived blood products to restore adequate hemostasis. Adult and pediatric data demonstrate associations between blood product transfusions and adverse patient outcomes. Thus, efforts to limit bleeding after pediatric cardiopulmonary bypass and minimize allogeneic blood product exposure are warranted. The off-label use of factor concentrates, such as fibrinogen concentrate, recombinant activated factor VII, and prothrombin complex concentrates, is increasing as these hemostatic agents appear to offer several advantages over conventional blood products. However, recognizing that these agents have the potential for both benefit and harm, well-designed studies are needed to enhance our knowledge and to determine the optimal use of these agents. In this review, our primary objective was to examine the evidence regarding the use of factor concentrates to treat bleeding after pediatric CPB and identify where further research is required. PubMed, MEDLINE/OVID, The Cochrane Library and the Cochrane Central Register of Controlled Trials (CENTRAL) were systematically searched to identify existing studies. © 2017 John Wiley & Sons Ltd.

The impact of land use on microbial surface water pollution.

PubMed

Schreiber, Christiane; Rechenburg, Andrea; Rind, Esther; Kistemann, Thomas

2015-03-01

Our knowledge relating to water contamination from point and diffuse sources has increased in recent years and there have been many studies undertaken focusing on effluent from sewage plants or combined sewer overflows. However, there is still only a limited amount of microbial data on non-point sources leading to diffuse pollution of surface waters. In this study, the concentrations of several indicator micro-organisms and pathogens in the upper reaches of a river system were examined over a period of 16 months. In addition to bacteria, diffuse pollution caused by Giardia lamblia and Cryptosporidium spp. was analysed. A single land use type predestined to cause high concentrations of all microbial parameters could not be identified. The influence of different land use types varies between microbial species. The microbial concentration in river water cannot be explained by stable non-point effluent concentrations from different land use types. There is variation in the ranking of the potential of different land use types resulting in surface water contamination with regard to minimum, median and maximum effects. These differences between median and maximum impact indicate that small-scale events like spreading manure substantially influence the general contamination potential of a land use type and may cause increasing micro-organism concentrations in the river water by mobilisation during the next rainfall event. Copyright © 2014 Elsevier GmbH. All rights reserved.

Quantification of total and particulate dimethylsulfoniopropionate (DMSP) in five Bermudian coral species across a depth gradient

NASA Astrophysics Data System (ADS)

Yost, D. M.; Jones, R.; Rowe, C. L.; Mitchelmore, Carys Louise

2012-06-01

The symbiotic dinoflagellate microalgae of corals ( Symbiodinium spp.) contain high concentrations of dimethylsulfoniopropionate (DMSP), a multifunctional metabolite commonly found in many species of marine algae and dinoflagellates. A photoprotective antioxidant function for DMSP and its breakdown products has often been inferred in algae, but its role(s) in the coral-algal symbiosis remains elusive. To examine potential correlations between environmental and physiological parameters and DMSP, total DMSP (DMSPt, from the host coral and zooxanthellae), particulate DMSP (DMSPp, from the zooxanthellae only), coral surface area, and total protein, as well as zooxanthellae density, chlorophyll concentration, cell volume and genotype (i.e., clade) were measured in five coral species from the Diploria- Montastraea- Porites species complex in Bermuda along a depth gradient of 4, 12, 18, and 24 m. DMSPt concentrations were consistently greater than DMSPp concentrations in all species suggesting the possible translocation of DMSP from symbiont to host. D. labyrinthiformis was notably different from the other corals examined, showing DMSPp and DMSPt increases (per coral surface area or tissue biomass) with increasing water depth. However, overall, there were no consistent depth-related patterns in DMSPp and DMSPt concentrations. Further research, investigating dimethylsulfide (DMS), dimethylsulfoxide, and acrylate levels and DMSP-lyase activity in correlation with other biomarker endpoints that have been shown to be depth (i.e., temperature and light) responsive are needed to substantiate the significance of these findings.

Lead poisoning in six captive avian species

USGS Publications Warehouse

Beyer, W. Nelson; Spann, James W.; Sileo, Louis; Franson, J. Christian

1988-01-01

Red-winged blackbirds (Agelaius phoeniceus), brown-headed cowbirds (Molothrus ater), common grackles (Quiscalus quiscula), mallards (Anas platyrhynchos), northern bobwhites (Colinus virginianus), and eastern screech-owls (Otus asio) were poisoned with a concentration of lead (Pb) acetate in the diet which was increased by 60% each week until half of the birds in each treatment group died; surviving birds and all control birds except screech-owis were then killed by euthanasia. An additional group of mallards was poisoned with Pb shot. The gizzards of mallards poisoned either way usually were stained with bile; some of these birds also had proventricular impaction. Most poisoned birds of the other species were emaciated but lacked other gross lesions caused by Pb poisoning. In birds other than mallards, Pb poisoning could not be diagnosed without histological or hematological examinations or analysis of tissues. Poisoned birds of all six species could be reliably separated from control birds by an increase in the protoporphyrin concentrations in the blood and by a decrease in the activity of delta-aminolevulinic acid dehydratase (ALAD) in red blood cells. Hepatic iron (Fe) concentrations varied so much among individual birds that even though median hepatic Fe concentrations increased in poisoned birds, hepatic Fe concentrations were not useful in identifying poisoned birds. Renal intranuclear inclusion bodies occurred in 83% of all birds dying from Pb poisoning. Nephrosis, myocardial necrosis, and arterial fibrinoid necrosis were occasionally present. Median hepatic Pb concentrations varied from 20 ppm (wet wt) in male red-winged blackbirds to 111 ppm in female northern bobwhites. Median renal Pb concentrations varied from 22 ppm in redwinged blackbirds to 190 ppm in female northern bobwhites. Hepatic and renal Pb concentrations varied substantially among birds within each species. Median hepatic and renal Pb concentrations of birds that died were not statistically different (p > 0.05) from those of birds that were killed. Lead shot and Pb acetate affected mallards similarly.

Water and sediment quality of the Lake Andes and Choteau Creek basins, South Dakota, 1983-2000

USGS Publications Warehouse

Sando, Steven Kent; Neitzert, Kathleen M.

2003-01-01

The Bureau of Reclamation has proposed construction of the Lake Andes/Wagner Irrigation Demonstration Project to investigate environmental effects of irrigation of glacial till soils substantially derived from marine shales. During 1983-2000, the U.S. Geological Survey collected hydrologic, water-quality, and sediment data in the Lake Andes and Choteau Creek Basins, and on the Missouri River upstream and downstream from Choteau Creek, to provide baseline information in support of the proposed demonstration project. Lake Andes has a drainage area of about 230 mi2 (square miles). Tributaries to Lake Andes are ephemeral. Water-level fluctuations in Lake Andes can be large, and the lake has been completely dry on several occasions. The outlet aqueduct from Lake Andes feeds into Garden Creek, which enters Lake Francis Case just upstream from Fort Randall Dam on the Missouri River. For Lake Andes tributary stations, calcium, magnesium, and sodium are approximately codominant among the cations, and sulfate is the dominant anion. Dissolved-solids concentrations typically range from about 1,000 mg/L (milligrams per liter) to about 1,700 mg/L. Major-ion concentrations for Lake Andes tend to be higher than the tributaries and generally increase downstream in Lake Andes. Proportions of major ions are similar among the different lake units (with the exception of Owens Bay), with calcium, magnesium, and sodium being approximately codominant among cations, and sulfate being the dominant anion. Owens Bay is characterized by a calcium sulfate water type. Dissolved-solids concentrations for Lake Andes typically range from about 1,400 to 2,000 mg/L. Whole-water nitrogen and phosphorus concentrations are similar among the Lake Andes tributaries, with median whole-water nitrogen concentrations ranging from about 1.6 to 2.4 mg/L, and median whole-water phosphorus concentrations ranging from about 0.5 to 0.7 mg/L. Whole-water nitrogen concentrations in Lake Andes are similar among the different units, with medians that range from about 2.4 to 4.0 mg/L. Median whole-water phosphorus concentrations for the different Lake Andes units range from 0.2 to 0.5 mg/L, and decrease downstream through Lake Andes. Median selenium concentrations are substantially lower for Andes Creek (3 ?g/L (micrograms per liter)) than for the other tributary stations (34, 18, and 7 ?g/L). Median selenium concentrations for the lake stations (ranging from less than 1 to 2 ?g/L) are substantially lower than tributary stations. The pesticides 2,4-D and atrazine were the most commonly detected pesticides in Lake Andes. Median concentrations for 2,4-D for Lake Andes range from 0.07 to 0.11 ?g/L; the median concentration for Owens Bay is 0.04 ?g/L. Median concentrations for atrazine for Lake Andes range from 0.2 to 0.4 ?g/L; the median concentration for Owens Bay is less than 0.1 ?g/L. Concentrations of both 2,4-D and atrazine are largest for the most upstream part of Lake Andes that is most influenced by tributary inflow. Median suspended-sediment concentrations for Lake Andes tributaries range from 22 to 56 mg/L. Most of the suspended sediment transported in the Lake Andes tributaries consists of particles less than 63 ?m (micrometers) in diameter. Concentrations of most constituents in bottom sediments generally had similar ranges and medians for the Lake Andes tributaries. However, Andes Creek generally had lower concentrations of several metals. For Lake Andes, medians and ranges for most constituents generally were similar among the different units. However, selenium concentrations tended to be higher in the upstream part of the lake, and generally decreased downstream. Results of vertical sediment cores collected from a single site in the South Unit of Lake Andes in October 2000 indicate that selenium loading to Lake Andes increased during the period 1952 through 2000. Choteau Creek has a drainage area of 619 mi2. In the upstream part of the basin, Chotea

The effect of experimental gastric dilatation-volvulus on adenosine triphosphate content and conductance of the canine gastric and jejunal mucosa.

PubMed

Peycke, Laura E; Hosgood, Giselle; Davidson, Jacqueline R; Tetens, Joanne; Taylor, H Wayne

2005-07-01

The objective of this study was to determine if experimental gastric dilatation volvulus (GDV) would decrease adenosine triphosphate (ATP) concentration and increase membrane conductance of the canine gastric and jejunal mucosa. Male dogs (n = 15) weighing between 20 and 30 kg were used. Dogs were randomly assigned to 1 of 3 equal groups: Group 1 was control, group 2 was GDV, and group 3 was ischemia. All dogs were anesthetized for 210 min. Group 1 had no manipulation. Group 2 had GDV experimentally induced for 120 min followed by decompression, derotation, and reperfusion for 90 min. Group 3 had GDV experimentally induced for 210 min. Gastric (fundus and pylorus) and jejunal tissue was taken at 0, 120, and 210 min from all of the dogs. Tissue was analyzed for ATP concentration, mucosal conductance, and microscopic changes. The ATP concentration in the fundus did not change significantly from baseline in group 2, but decreased significantly below baseline at 210 min in group 3. The ATP concentration in the jejunum decreased significantly below baseline in groups 2 and 3 at 120 min, remaining significantly decreased in group 3 but returning to baseline at 210 min in group 2. Mucosal conductance of the fundus did not change significantly in any dog. Mucosal conductance of the jejunum increased at 120 min in groups 2 and 3, and became significantly increased above baseline at 210 min. The jejunal mucosa showed more profound cellular changes than the gastric mucosa. The jejunum showed substantial decreases in ATP concentration with an increase in mucosal conductance, suggesting cell membrane dysfunction. Dogs sustaining a GDV are likely to have a change in the activity of mucosal cells in the jejunum, which may be important in the pathophysiology of GDV.

Chemical, isotopic, and microbiological evidence for denitrification during transport of domestic wastewater through a thick unsaturated zone in the Mojave Desert, San Bernardino County, California

USGS Publications Warehouse

Schroeder, R.A.; Martin, P.M.; Böhlke, J.K.

1993-01-01

Nitrogen in downward-infiltrating wastewater discharged from seepage pits (dry wells) at residences in the upper Mojave River Basin, California represents a significant potential source of nitrate contamination to the underlying ground water. However, increases in nitrate concentration in the ground water have not yet been observed. The low nitrate concentration in the ground water may be the result of lateral dispersion in the unsaturated zone, dilution below the water table, or denitrification of wastewater nitrate in the unsaturated zone. Measured vertical rates indicate that some wastewater has reached the water table beneath communities that are older than 5 to 10 years. As wastewater percolates from seepage pits into the unsaturated zone, reduced nitrogen is converted rapidly to nitrate at shallow depths and the nitrate concentrations commonly decrease with depth. The largest nitrate decreases seem to coincide with increased content of fine-grained sediments or with proximity to the water table. Between lysimeters at 160 and 199 feet at one residence, the decrease in nitrate concentration coincided with a large increase in sulfate, decrease in alkalinity, and increase in 815N in nitrate. Those data are consistent with denitrification by oxidation of iron sulfide to produce ferric oxides; but if such a reaction occurs, it must be in domains that are small in comparison with the sampled volumes because the waters also contain substantial quantities of dissolved oxygen. The predominantly low nitrate concentrations in the area's ground water are consistent with the operation of a nitrogen-removal mechanism, possibly denitrification; however, the reducing capacity of the sediments to maintain denitrification is not known.

Oxidative stress and antioxidant responses to increasing concentrations of trivalent chromium in the Andean crop species Chenopodium quinoa Willd.

PubMed

Scoccianti, Valeria; Bucchini, Anahi E; Iacobucci, Marta; Ruiz, Karina B; Biondi, Stefania

2016-11-01

Quinoa (Chenopodium quinoa Willd), an ancient Andean seed crop, exhibits exceptional nutritional properties and resistance to abiotic stress. The species' tolerance to heavy metals has, however, not yet been investigated nor its ability to take up and translocate chromium (Cr). This study aimed to investigate the metabolic adjustments occurring upon exposure of quinoa to several concentrations (0.01-5mM) of CrCl3. Young hydroponically grown plants were used to evaluate Cr uptake, growth, oxidative stress, and other biochemical parameters three and/or seven days after treatment. Leaves accumulated the lowest amounts of Cr, while roots and stems accumulated the most at low and at high metal concentrations, respectively. Fresh weight and photosynthetic pigments were reduced only by the higher Cr(III) doses. Substantially increased lipid peroxidation, hydrogen peroxide, and proline levels were observed only with 5mM Cr(III). Except for a significant decrease at day 7 with 5mM Cr(III), total polyphenols and flavonoids maintained control levels in Cr(III)-treated plants, whereas antioxidant activity increased in a dose-dependent manner. Maximum polyamine accumulation was observed in 1mM CrCl3-treated plants. Even though α- and γ-tocopherols also showed enhanced levels only with the 1mM concentration, tyrosine aminotransferase (TAT, EC 2.6.1.5) activity increased under Cr(III) treatment in a dose- and time-dependent manner. Taken together, results suggest that polyamines, tocopherols, and TAT activity could contribute to tolerance to 1mM Cr(III), but not to the highest concentration that, instead, generated oxidative stress. Copyright © 2016 Elsevier Inc. All rights reserved.

Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals

USGS Publications Warehouse

Peterson, Sarah H.; Ackerman, Joshua T.; Costa, Daniel P.

2015-01-01

Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200–1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and δ13C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation.

Serum and urinary thioredoxin concentrations are associated with severity of children hydronephrosis.

PubMed

Xu, Zhe-Ming; Li, Min-Ju; Tao, Chang

2017-03-01

Ureteropelvic junction obstruction (UPJO) is the most common cause of hydronephrosis in children. This study was to assess the relationship between serum thioredoxin (S-Trx) and urinary thioredoxin (U-Trx) concentrations and severity of children hydronephrosis caused by UPJO. This study included 156 hydronephrosis children with unilateral UPJO and 80 healthy children. S-Trx and U-Trx concentrations were measured using enzyme-linked immunosorbent assay. U-Trx/creatinine (cr) ratio was calculated. S-Trx and U-Trx concentrations and U-Trx/cr ratio were significantly higher in hydronephrosis children than in healthy children. They were significantly correlated with split renal function, anterior-posterior diameter and Society for Fetal Urology classification, as well as were independently related to the split renal function <39.2%, anterior-posterior diameter>30mm and Society for Fetal Urology grade IV. Under receiver operating characteristic curves, U-Trx/cr ratio showed the higher predictive value compared to S-Trx and U-Trx concentrations. Increased S-Trx and U-Trx concentrations, especially U-Trx/cr ratio, are closely associated with the severity of children hydronephrosis, substantializing Trx as a promising biomarker for the progression of children hydronephrosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Maternal Behavior and Physiological Stress Levels in Wild Chimpanzees (Pan troglodytes schweinfurthii).

PubMed

Stanton, Margaret A; Heintz, Matthew R; Lonsdorf, Elizabeth V; Santymire, Rachel M; Lipende, Iddi; Murray, Carson M

2015-06-01

Individual differences in maternal behavior toward, and investment in, offspring can have lasting consequences, particularly among primate taxa characterized by prolonged periods of development over which mothers can exert substantial influence. Given the role of the neuroendocrine system in the expression of behavior, researchers are increasingly interested in understanding the hormonal correlates of maternal behavior. Here, we examined the relationship between maternal behavior and physiological stress levels, as quantified by fecal glucocorticoid metabolite (FGM) concentrations, in lactating chimpanzees, Pan troglodytes schweinfurthii , at Gombe National Park, Tanzania. After accounting for temporal variation in FGM concentrations, we found that mothers interacted socially (groomed and played) with and nursed their infants more on days when FGM concentrations were elevated compared to days when FGM concentrations were within the range expected given the time of year. However, the proportion of time mothers and infants spent in contact did not differ based on FGM concentrations. These results generally agree with the suggestion that elevated GC concentrations are related to maternal motivation and responsivity to infant cues and are the first evidence of a hormonal correlate of maternal behavior in a wild great ape.

FIM/atom probe analysis of a heat treated 7150 aluminum alloy

NASA Astrophysics Data System (ADS)

Brenner, S. S.; Kowalik, J.; Hua Ming-Jian

1991-04-01

The stress corrosion cracking resistance of high strength aluminum alloys can be substantially altered by heat treatment. In addition to microstructural changes, the alloys may also undergo chemical changes as a result of the heat treatment which may affect the stress corrosion properties. The FIM/atom probe has been used to detect such changes. The compositions of the matrix, matrix precipitates, precipitate-free zone (PFZ) and grain boundary precipitates in a heat-treated 7150 Al alloy tempered to peak strength have been quantitatively measured. A substantial increase in the concentrations of Mg, Zn and Cu were found in the PFZ. The average compositions of the precipitates in the matrix and at the sub-boundaries were shown not to differ significantly. The coarser precipitates at high-angle boundaries, which may have a more important effect on stress corrosion, were difficult to analyze because of their low number density and the large grain size of the material.

Insulin in human milk and the prevention of type 1 diabetes.

PubMed

Shehadeh, N; Shamir, R; Berant, M; Etzioni, A

2001-12-01

Although controversial, exclusive breast milk feeding was shown to exert a protective effect in preventing type 1 diabetes. In contrast, an early introduction of cow's milk-based formula in young infants may enhance the risk of disease, especially in genetically susceptible children, presumably by an increase of intestinal permeability to macromolecules such as bovine serum albumin and beta-casein, which may arouse autoimmunity. We have shown that human milk contains insulin in substantial concentrations, while insulin is barely detectable (if at all) in infant formulas. Orally administered insulin was demonstrated to promote gut maturation and to reduce intestinal permeability to macromolecules. Furthermore, oral insulin may induce tolerance to insulin and protect against the development of type 1 diabetes. We herewith raise a hypothesis that human milk is protective against the development of type 1 diabetes by virtue of the effects of its substantial content of insulin.

Effect of gaseous ammonia on nicotine sorption

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webb, A.M.; Singer, B.C.; Nazaroff, W.W.

2002-06-01

Nicotine is a major constituent of environmental tobacco smoke. Sorptive interactions of nicotine with indoor surfaces can substantially alter indoor concentrations. The phenomenon is poorly understood, including whether sorption is fully reversible or partially irreversible. They hypothesize that acid-base chemistry on indoor surfaces might contribute to the apparent irreversibility of nicotine sorption under some circumstances. Specifically, they suggest that nicotine may become protonated on surfaces, markedly reducing its vapor pressure. If so, subsequent exposure of the surface to gaseous ammonia, a common base, could raise the surface pH, causing deprotonation and desorption of nicotine from surfaces. A series of experimentsmore » was conducted to explore the effect of ammonia on nicotine sorption to and reemission from surfaces. The results indicate that, under some conditions, exposure to gaseous ammonia can substantially increase the rate of desorption of previously sorbed nicotine from common indoor surface materials.« less

Changes in sub-soil river water quality upon its open storage-a case study.

PubMed

Mohanty, A K; Satpathy, K K; Prasad, M V R

2017-08-01

A study was carried out to investigate the changes in the physicochemical and biological properties of sub-soil river water upon its storage in a man-made reservoir. Palar sub-soil and reservoir water samples were collated fortnightly for a period of 5 years (2010-2014). The open reservoir is used as a reliable raw water source for condenser cooling systems and for the demineralizing (DM) plant input of Fast Breeder Test Reactor (FBTR), Madras Atomic Power Station (MAPS), and other laboratories at Kalpakkam, southeast coast of India. Relatively high nutrient concentration was observed in the Palar sub-soil water, and a significant reduction in average concentration (μmol l -1 ) of phosphate (Palar 1.92; open reservoir 1.54) and nitrate (Palar 9.78; open reservoir 5.67) was observed from Palar to open reservoir. Substantial increase in pH (Palar 8.05; open reservoir 8.45), dissolved oxygen (mg l -1 ) (Palar 6.07; open reservoir 8.47), and chlorophyll-a (mg m -3 ) (Palar 1.66; open reservoir 8.43) values were noticed from the Palar sub-soil water to open reservoir water. It is concluded that sub-soil water with higher nutrient concentrations when stored openly, exposing to the sun, resulted in growth of plants, planktonic, and macrophytes, which led to substantial deterioration in water quality from its utility point of view as a condenser cooling medium and raw water input for DM plant.

Impacts of a Rural Subdivision on Groundwater Quality: Results of Long-Term Monitoring.

PubMed

Rayne, Todd W; Bradbury, Kenneth R; Krause, Jacob J

2018-03-30

A rural subdivision in south central Wisconsin was instrumented with monitoring wells and lysimeters before, during, and after its construction to examine the impacts of the unsewered subdivision on groundwater quality and quantity. Prior to construction, the 78-acre (32 ha) site was farmland. Sixteen homes were constructed beginning in 2003. Initial monitoring from 2002 to 2005 showed that groundwater beneath the site had been impacted by previous agricultural use, with nitrate-N values as high as 30 mg/L and some detections of the herbicide atrazine. Our 12-year study shows that the transition from agricultural to residential land use has changed groundwater quality in both negative and positive ways. Although groundwater elevations showed typical seasonal fluctuations each year, there were no measurable changes in groundwater levels or general flow directions during the 12-year study period. Chloride values increased in many wells, possibly as a result of road salting or water softener discharge. Nitrate concentrations varied spatially and temporally over the study period, with some initial concentrations substantially above the drinking water standard. In some wells, nitrate and atrazine levels have declined substantially since agriculture ceased. However, atrazine was still present at trace concentrations throughout the site in 2014. Wastewater tracers show there are small but detectable impacts from septic effluent on groundwater quality. Particle traces based on a groundwater flow model are consistent with the hypothesis that septic leachate has impacted groundwater quality. © 2018, National Ground Water Association.

An approach to quantify sources, seasonal change, and biogeochemical processes affecting metal loading in streams: Facilitating decisions for remediation of mine drainage

USGS Publications Warehouse

Kimball, B.A.; Runkel, R.L.; Walton-Day, K.

2010-01-01

Historical mining has left complex problems in catchments throughout the world. Land managers are faced with making cost-effective plans to remediate mine influences. Remediation plans are facilitated by spatial mass-loading profiles that indicate the locations of metal mass-loading, seasonal changes, and the extent of biogeochemical processes. Field-scale experiments during both low- and high-flow conditions and time-series data over diel cycles illustrate how this can be accomplished. A low-flow experiment provided spatially detailed loading profiles to indicate where loading occurred. For example, SO42 - was principally derived from sources upstream from the study reach, but three principal locations also were important for SO42 - loading within the reach. During high-flow conditions, Lagrangian sampling provided data to interpret seasonal changes and indicated locations where snowmelt runoff flushed metals to the stream. Comparison of metal concentrations between the low- and high-flow experiments indicated substantial increases in metal loading at high flow, but little change in metal concentrations, showing that toxicity at the most downstream sampling site was not substantially greater during snowmelt runoff. During high-flow conditions, a detailed temporal sampling at fixed sites indicated that Zn concentration more than doubled during the diel cycle. Monitoring programs must account for diel variation to provide meaningful results. Mass-loading studies during different flow conditions and detailed time-series over diel cycles provide useful scientific support for stream management decisions.

Concentration changes of organochlorine compounds and polybromodiphenyl ethers during metamorphosis of aquatic insects.

PubMed

Bartrons, Mireia; Grimalt, Joan O; Catalan, Jordi

2007-09-01

The role of insect larvae and pupae as sources of organochlorine compounds (OCs) and polybromodiphenyl ethers (PBDEs) in freshwater food webs for high predators such as fish is evaluated. Trichoptera and diptera have been taken as organisms of choice for such comparison because they are common in benthic aquatic habitats and accumulate substantial amounts of these compounds. Hexachlorobenzene, hexachlorocyclohexanes,4,4'-DDE,4,4'-DDT, polychlorobiphenyls, and PBDEs have been measured. The results show a nonselective enrichment of OCs and PBDEs from larvae to pupae. These concentration increases may result from the weight loss of pupae during metamorphosis as a consequence of mainly protein carbon respiration and lack of feeding. Despite the lack of change in total amount, the concentration increases from larvae to pupae are very relevant for the pollutant ingestion of the higher predators. The intakes of OCs and PBDEs by trout are between 2- and 5-fold higher per calorie gained when predating on pupae than on larvae. Since pollutant concentration, energy reward, predation susceptibility, and duration of life stage are very different between these two insect stages, and none of them is irrelevant for the incorporation of OCs or PBDEs to higher levels, bioaccumulation food-web models should distinguish between the two sources.

WITHAFERIN A INDUCES APOPTOSIS IN RAT C6 GLIOMA CELLS THROUGH REGULATING NF-KB NUCLEAR TRANSLOCATION AND ACTIVATION OF CASPASE CASCADE.

PubMed

Hou, Wei-Chen; Miao, Xiao-Hui; Ma, Lian-Jun; Bai, Xiao-Xue; Liu, Qun; Song, Lei

2017-01-01

The demand for the chemopreventive drug from the plant source is increasing in recent times, owing to its various biological activities without any adverse effect. The intention of this current study was to examine the anti-glioma effect of Withaferin A (WFA) on C6 glioma cell line model. C6 glioma cells were administrated with different concentration of WFA (50, 100, 200 and 500 μg/mL) and DMSO (control) group to examine its anti-proliferative, anti-inflammatory and pro-apoptotic activities. Treatment with WFA showed a significant decline in the glioma cell count in a dose-dependent manner and thus proving its anti-proliferative effect. Similarly, inflammatory markers were also substantially lowered upon treatment with different concentration of WFA. However, DNA fragmentation and apoptotic markers like Caspase-3 and 9 were concomitantly enhanced after co-cultured with different concentration of WFA and thus exhibiting its cytotoxicity efficacy. Furthermore, the protein expression of Bcl2 and Bax were markedly downregulated and upregulated respectively; upon treatment with WFA on C6 glioma cells. The outcome of this study evidently demonstrates that C6 glioma cells co-cultured with increased concentration of WFA, showed an anti-proliferative, anti-inflammatory and pro-apoptotic effect in a dose-dependent fashion.

Effects of amitriptyline and clomipramine in the isolated, perfused rabbit heart.

PubMed

Nielsen-Kudsk, F; Quist, S

1980-04-01

The cardiac effects of supratherapeutic concentrations of two tricyclic antidepressants were studied in isolated rabbit hearts, which were perfused with a modified Krebs-Henseleit solution containing 0.25 or 0.50 micrograms ml-1 of amitriptyline or 0.28 micrograms mg-1 of clomipramine. The following parameters were continuously recorded:heart rate, amplitude and rate of contraction, coronary flow rate, myocardial oxygen consumption and ECG. The lowest concentration of amitriptyline caused a time correlated decrease (20%) in the frequency of spontaneous beating and a pronounced decrease in the amplitude (62%) and rate of cardiac contraction (58%). Maximum increases of the PQ-interval of about 46% and of the QRS-complex of about 100% were observed. At the higher amitriptyline concentration these effect further increased. Clomipramine 0.28 micrograms ml-1 also had a very pronounced and time correlated negative inotropic effect, but the effects upon the conduction velocities were substantially lesser than those produced by the equimilar concentration of amitriptyline. The compounds caused only insignificant changes in coronary flow. The oxygen consumption did not decrease in proportion to the decrease in contractility, as an expression of decreased myocardial efficiency. The effects of the drugs are discussed in relation to theri myocardial accumulation pharmacokinetics and influence upon the membraneous sodium and calcium flux and intracellular metabolism.

Cortisol in saliva and plasma of cattle after ACTH administration and milking.

PubMed

Negrão, J A; Porcionato, M A; de Passillé, A M; Rushen, J

2004-06-01

Interest in the measurement of salivary cortisol has increased recently because saliva can be easily collected before and after an imposed stress. This study evaluated the relationship between plasma and salivary concentrations of cortisol following ACTH administration in calves (experiment 1) and machine milking of adult cows (experiment 2). A catheter was inserted into the jugular vein of all animals 72 h before the beginning of experiments. Blood and saliva samples were collected before and after ACTH administration (0.6 IU/kg BW) in calves or before and after machine milking of cows. Using a cotton swab, each saliva sample was taken immediately following the blood sample. In general, cortisol profiles were similar in plasma and saliva and correlated in both experiments; however, plasma concentrations were significantly higher than salivary concentrations. In addition, the differences between cortisol concentrations measured in saliva and plasma within each experiment varied substantially between animals and samples. Furthermore, in experiment 2, nearly 10% of salivary samples were below limits of detection. The sharp peaks in cortisol after ACTH administration in both the plasma and saliva were reflected adrenal stimulation. In addition, increases in cortisol in response to milking in both the plasma and saliva suggest that salivary sampling is a reliable option when studying cortisol responses to normal physiological events.

Salt acclimation process: a comparison between a sensitive and a tolerant Olea europaea cultivar.

PubMed

Pandolfi, Camilla; Bazihizina, Nadia; Giordano, Cristiana; Mancuso, Stefano; Azzarello, Elisa

2017-03-01

Saline soils are highly heterogeneous in time and space, and this is a critical factor influencing plant physiology and productivity. Temporal changes in soil salinity can alter plant responses to salinity, and pre-treating plants with low NaCl concentrations has been found to substantially increase salt tolerance in different species in a process called acclimation. However, it still remains unclear whether this process is common to all plants or is only expressed in certain genotypes. We addressed this question by assessing the physiological changes to 100 mM NaCl in two contrasting olive cultivars (the salt-sensitive Leccino and the salt-tolerant Frantoio), following a 1-month acclimation period with 5 or 25 mM NaCl. The acclimation improved salt tolerance in both cultivars, but activated substantially different physiological adjustments in the tolerant and the sensitive cultivars. In the tolerant Frantoio the acclimation with 5 mM NaCl was more effective in increasing plant salt tolerance, with a 47% increase in total plant dry mass compared with non-acclimated saline plants. This enhanced biomass accumulation was associated with a 50% increase in K+ retention ability in roots. On the other hand, in the sensitive Leccino, although the acclimation process did not improve performance in terms of plant growth, pre-treatment with 5 and 25 mM NaCl substantially decreased salt-induced leaf cell ultrastructural changes, with leaf cell relatively similar to those of control plants. Taken together these results suggest that in the tolerant cultivar the acclimation took place primarily in the root tissues, while in the sensitive they occurred mainly at the shoot level. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The toxic effects of silver nanoparticles on blood mononuclear cells.

PubMed

Barkhordari, A; Barzegar, S; Hekmatimoghaddam, H; Jebali, A; Rahimi Moghadam, S; Khanjani, N

2014-07-01

Nanoparticles have become one of the leading technologies over the past two years. The extensive use of nanoparticles has raised great concern about their occupational fate and biological effects. With an increase in the production and use of nanomaterial, it is more likely to get exposed to them occupationally and environmentally. To assess the toxicity of silver nanoparticles on human mononuclear cells. In this in vitro experimental study, suspensions of blood mononuclear cells from 10 young healthy men were incubated with 10-nm silver nanoparticles in different concentrations (range: 1-500 μg/mL) for 6 and 24 hours by MTT assay. Positive and negative controls were used for comparison. After 6 hours of exposure, 10.9% to 48.4% of the cells died. After 24 hours of exposure, the rate ranged from 56.8% to 86.3%. Regardless of the exposure time, the maximum cytotoxicity was observed at the concentration of 500 μg/mL of silver nanoparticles. By increasing the exposure time to 24 hours, the cytotoxicity of nanoparticles substantially increased at all concentrations. Cell death was significantly higher when compared to the controls (p<0.01). Silver nanoparticles possess both time- and dose-dependent cytotoxicity and can thus be considered as very toxic for mononuclear cells.

Effects of heavy metals (Fe3+/Cr6+) on low-level energy generation in a microbial fuel cell

NASA Astrophysics Data System (ADS)

Caparanga, A. R.; Balatbat, A. S.; Tayo, L.

2017-06-01

A dual-chamber microbial fuel cell (MFC) was constructed with Pseudomonas aeruginosa as biocatalyst to facilitate substrate conversion and, consequently, low-level energy generation. To simulate a wastewater situation with BOD and heavy metals contamination, glucose and Fe3+ and Cr6+ were used as substrate and heavy-metal spikes, respectively. The effects of varying substrate concentrations (150 ppm, 300 ppm, 600 ppm) and heavy metal loads (10 ppm, 50 ppm, 100 ppm) on overall power generation were evaluated. The presence of Cr6+ in the anode compartment decreased the potential from 565 to 201 mV (i.e., lowest value achieved at highest Cr6+ concentration of 300 ppm). On the other hand, replacing Cr6+ with Fe3+ as electron acceptor resulted in substantial increase in measured potential (i.e., from 565 to 703 mV). Increasing glucose concentrations resulted in longer time to reach constant open circuit voltage. A maximum potential of 606 mV was achieved at 1200 ppm glucose. Incorporating Pseudomonas aeruginosa increased the potential from 256 to 592 mV. On the basis of these results, a microbial fuel cell feeding on wastewater can be an important potential technology for generating low-level energy

Onset and ending of the late Palaeozoic ice age triggered by tectonically paced rock weathering

NASA Astrophysics Data System (ADS)

Goddéris, Yves; Donnadieu, Yannick; Carretier, Sébastien; Aretz, Markus; Dera, Guillaume; Macouin, Mélina; Regard, Vincent

2017-04-01

The onset of the late Palaeozoic ice age about 340 million years ago has been attributed to a decrease in atmospheric CO2 concentrations associated with expansion of land plants, as plants both enhance silicate rock weathering--which consumes CO2--and increase the storage of organic carbon on land. However, plant expansion and carbon uptake substantially predate glaciation. Here we use climate and carbon cycle simulations to investigate the potential effects of the uplift of the equatorial Hercynian mountains and the assembly of Pangaea on the late Palaeozoic carbon cycle. In our simulations, mountain uplift during the Late Carboniferous caused an increase in physical weathering that removed the thick soil cover that had inhibited silicate weathering. The resulting increase in chemical weathering was sufficient to cause atmospheric CO2 concentrations to fall below the levels required to initiate glaciation. During the Permian, the lowering of the mountains led to a re-establishment of thick soils, whilst the assembly of Pangaea promoted arid conditions in continental interiors that were unfavourable for silicate weathering. These changes allowed CO2 concentrations to rise to levels sufficient to terminate the glacial event. Based on our simulations, we suggest that tectonically influenced carbon cycle changes during the late Palaeozoic were sufficient to initiate and terminate the late Palaeozoic ice age.

Effect of cobalt on Escherichia coli metabolism and metalloporphyrin formation

PubMed Central

Majtan, Tomas; Frerman, Frank E.

2011-01-01

Toxicity in Escherichia coli resulting from high concentrations of cobalt has been explained by competition of cobalt with iron in various metabolic processes including Fe–S cluster assembly, sulfur assimilation, production of free radicals and reduction of free thiol pool. Here we present another aspect of increased cobalt concentrations in the culture medium resulting in the production of cobalt protoporphyrin IX (CoPPIX), which was incorporated into heme proteins including membrane-bound cytochromes and an expressed human cystathionine beta-synthase (CBS). The presence of CoPPIX in cytochromes inhibited their electron transport capacity and resulted in a substantially decreased respiration. Bacterial cells adapted to the increased cobalt concentration by inducing a modified mixed acid fermentative pathway under aerobiosis. We capitalized on the ability of E. coli to insert cobalt into PPIX to carry out an expression of CoPPIX-substituted heme proteins. The level of CoPPIX-substitution increased with the number of passages of cells in a cobalt-containing medium. This approach is an inexpensive method to prepare cobalt-substituted heme proteins compared to in vitro enzyme reconstitution or in vivo replacement using metalloporphyrin heme analogs and seems to be especially suitable for complex heme proteins with an additional coenzyme, such as human CBS. PMID:21184140

Review: The Potential of the Common Bean (Phaseolus vulgaris) as a Vehicle for Iron Biofortification

PubMed Central

Petry, Nicolai; Boy, Erick; Wirth, James P.; Hurrell, Richard F.

2015-01-01

Common beans are a staple food and the major source of iron for populations in Eastern Africa and Latin America. Bean iron concentration is high and can be further increased by biofortification. A major constraint to bean iron biofortification is low iron absorption, attributed to inhibitory compounds such as phytic acid (PA) and polyphenol(s) (PP). We have evaluated the usefulness of the common bean as a vehicle for iron biofortification. High iron concentrations and wide genetic variability have enabled plant breeders to develop high iron bean varieties (up to 10 mg/100 g). PA concentrations in beans are high and tend to increase with iron biofortification. Short-term human isotope studies indicate that iron absorption from beans is low, PA is the major inhibitor, and bean PP play a minor role. Multiple composite meal studies indicate that decreasing the PA level in the biofortified varieties substantially increases iron absorption. Fractional iron absorption from composite meals was 4%–7% in iron deficient women; thus the consumption of 100 g biofortified beans/day would provide about 30%–50% of their daily iron requirement. Beans are a good vehicle for iron biofortification, and regular high consumption would be expected to help combat iron deficiency (ID). PMID:25679229

Alterations in cyclosporin A pharmacokinetics and metabolism during treatment with St John's wort in renal transplant patients

PubMed Central

Bauer, Steffen; Störmer, Elke; Johne, Andreas; Krüger, Hagen; Budde, Klemens; Neumayer, Hans-Hellmut; Roots, Ivar; Mai, Ingrid

2003-01-01

Aim This study investigated the effects of St John's wort extract (SJW) on the pharmacokinetics and metabolism of the immunosuppressant cyclosporin A (CSA). Methods In an open-label study, 11 renal transplant patients received 600 mg SJW extract daily for 14 days in addition to their regular regimen of CSA. Blood concentrations of CSA and its metabolites AM1, AM1C, AM9, AM19, and AM4N were measured by HPLC. Results After 2 weeks of SJW coadministration, dose-corrected AUC0–12, Cmax and Ctrough values for CSA decreased significantly by 46%[geometric mean ratio baseline/SJW (95% CI): 1.83 (1.63–2.05)], 42%[1.72 (1.42–2.08)], and 41%[1.70 (1.17–2.47)], respectively. CSA doses were increased from a median of 2.7 mg day−1 kg−1 at baseline to 4.2 mg day−1 kg−1 at day 15, with the first dose adjustment required only 3 days after initiation of SJW treatment. Additionally, the metabolite pattern of CSA was substantially altered during SJW treatment. Whereas dose-corrected AUC values for AM1, AM1c and AM4N significantly decreased by 59%, 61%, and 23% compared with baseline, AUC values for AM9 and AM19 were unchanged. Following the increase in CSA dose, observed AUC and Cmax values for AM9, AM19, and AM4N increased by 20–51% and 43–90%, respectively. Conclusion Administration of SJW extract to patients receiving CSA treatment resulted in a rapid and significant reduction of plasma CSA concentrations. Additionally, the substantial alterations in CSA metabolite kinetics observed may affect the toxicity profile of the drug. PMID:12580993

Melting mountains of Appalachia: exceptionally high weathering rates in mined watersheds

NASA Astrophysics Data System (ADS)

Ross, M. R.; Nippgen, F.; Hassett, B.; McGlynn, B. L.; Bernhardt, E. S.

2016-12-01

Mountaintop mining operations excavate ridges as deep as 200 m and bury adjacent valleys and streams beneath fractured bedrock and coal residues. Post-mining, landscapes have lower slopes, greatly increased water storage potential, and an abundance of acid-generating pyrite, which is intentionally mixed with neutralizing calcareous bedrock. Together these design features of mountaintop mined lands create ideal conditions for long water residence times and rapid weathering rates, leading to widely documented and substantial increases in streamwater ion concentrations. To date, these concentration changes have not been linked to rates of watershed scale element flux. In a paired catchment study, we documented a 4,000% increase in the export of total dissolved solids from a mined watershed, and estimate that pyrite and carbonate weathering in reclaimed mines can export 9,000 kg ha-1 y-1 of dissolved rock to receiving streams. Such high rates of element flux after a disturbance are not only much higher than other watershed disturbances, but are among the highest rates of weathering ever reported globally. Sulfuric acid weathering of carbonate rock drives these patterns of chemical erosion. This strong acid weathering changes Appalachian geology from a slight net geologic CO2 sink-sequestering 800-1,500 kg CO2 km-2 yr-1 through carbonic acid weathering of carbonates-to a substantial net geologic source of CO2, releasing 170,000 kg CO2 km-2 yr-1. Over the more than 4,000 km2 area of Central Appalachia that has undergone mountaintop mining, this rapid weathering represents 4 million tons of dissolved rock being delivered to the streams of West Virginia, potentially releasing 680,000 tons of CO2 in the process.

Behavioral Changes Over Time Following Ayahuasca Exposure in Zebrafish

PubMed Central

Savoldi, Robson; Polari, Daniel; Pinheiro-da-Silva, Jaquelinne; Silva, Priscila F.; Lobao-Soares, Bruno; Yonamine, Mauricio; Freire, Fulvio A. M.; Luchiari, Ana C.

2017-01-01

The combined infusion of Banisteriopsis caapi stem and Psychotria viridis leaves, known as ayahuasca, has been used for centuries by indigenous tribes. The infusion is rich in N, N-dimethyltryptamine (DMT) and monoamine oxidase inhibitors, with properties similar to those of serotonin. Despite substantial progress in the development of new drugs to treat anxiety and depression, current treatments have several limitations. Alternative drugs, such as ayahuasca, may shed light on these disorders. Here, we present time-course behavioral changes induced by ayahuasca in zebrafish, as first step toward establishing an ideal concentration for pre-clinical evaluations. We exposed adult zebrafish to five concentrations of the ayahuasca infusion: 0 (control), 0.1, 0.5, 1, and 3 ml/L (n = 14 each group), and behavior was recorded for 60 min. We evaluated swimming speed, distance traveled, freezing and bottom dwelling every min for 60 min. Swimming speed and distance traveled decreased with an increase in ayahuasca concentration while freezing increased with 1 and 3 ml/L. Bottom dwelling increased with 1 and 3 ml/L, but declined with 0.1 ml/L. Our data suggest that small amounts of ayahuasca do not affect locomotion and reduce anxiety-like behavior in zebrafish, while increased doses of the drug lead to crescent anxiogenic effects. We conclude that the temporal analysis of zebrafish behavior is a sensitive method for the study of ayahuasca-induced functional changes in the vertebrate brain. PMID:28804451

Behavioral Changes Over Time Following Ayahuasca Exposure in Zebrafish.

PubMed

Savoldi, Robson; Polari, Daniel; Pinheiro-da-Silva, Jaquelinne; Silva, Priscila F; Lobao-Soares, Bruno; Yonamine, Mauricio; Freire, Fulvio A M; Luchiari, Ana C

2017-01-01

The combined infusion of Banisteriopsis caapi stem and Psychotria viridis leaves, known as ayahuasca, has been used for centuries by indigenous tribes. The infusion is rich in N , N -dimethyltryptamine (DMT) and monoamine oxidase inhibitors, with properties similar to those of serotonin. Despite substantial progress in the development of new drugs to treat anxiety and depression, current treatments have several limitations. Alternative drugs, such as ayahuasca, may shed light on these disorders. Here, we present time-course behavioral changes induced by ayahuasca in zebrafish, as first step toward establishing an ideal concentration for pre-clinical evaluations. We exposed adult zebrafish to five concentrations of the ayahuasca infusion: 0 (control), 0.1, 0.5, 1, and 3 ml/L ( n = 14 each group), and behavior was recorded for 60 min. We evaluated swimming speed, distance traveled, freezing and bottom dwelling every min for 60 min. Swimming speed and distance traveled decreased with an increase in ayahuasca concentration while freezing increased with 1 and 3 ml/L. Bottom dwelling increased with 1 and 3 ml/L, but declined with 0.1 ml/L. Our data suggest that small amounts of ayahuasca do not affect locomotion and reduce anxiety-like behavior in zebrafish, while increased doses of the drug lead to crescent anxiogenic effects. We conclude that the temporal analysis of zebrafish behavior is a sensitive method for the study of ayahuasca-induced functional changes in the vertebrate brain.

Eotaxin increases monolayer permeability of human coronary artery endothelial cells.

PubMed

Jamaluddin, Md Saha; Wang, Xinwen; Wang, Hao; Rafael, Cubas; Yao, Qizhi; Chen, Changyi

2009-12-01

The objective of this study was to determine the effects and molecular mechanisms of eotaxin, a newly discovered chemokine (CCL11), on endothelial permeability in the human coronary artery endothelial cells (HCAECs). Cells were treated with eotaxin, and the monolayer permeability was studied by using a costar transwell system with a Texas Red-labeled dextran tracer. Eotaxin significantly increased monolayer permeability in a concentration-dependent manner. In addition, eotaxin treatment significantly decreased the mRNA and protein levels of endothelial junction molecules including zonula occludens-1 (ZO-1), occludin, and claudin-1 in a concentration-dependent manner as determined by real-time RT-PCR and Western blot analysis, respectively. Increased oxidative stress was observed in eotaxin-treated HCAECs by analysis of cellular glutathione levels. Furthermore, eotaxin treatment substantially activated the phosphorylation of MAPK p38. HCAECs expressed CCR3. Consequently, antioxidants (ginkgolide B and MnTBAP), specific p38 inhibitor SB203580, and anti-CCR3 antibody effectively blocked the eotaxin-induced permeability increase in HCAECs. Eotaxin also increased the phosphorylation of Stat3 and nuclear translocation of NF-kappaB in HCAECs. Eotaxin increases vascular permeability through CCR3, the downregulation of tight junction proteins, increase of oxidative stress, and activation of MAPK p38, Stat3, and NF-kB pathways in HCAECs.

Leaf water use efficiency of C{sub 4} plants grown at glacial to elevated CO{sub 2} concentrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polley, H.W.; Johnson, H.B.; Mayeux, H.S.

1995-09-01

Leaf gas exchange and stable carbon isotope compositions were measured on C{sub 4} species grown from near glacial to current CO{sub 2} concentrations (200 to 350 {mu}mol/mol) and from the current concentration to levels possible in the future (700 and 1000 {mu}mol/mol) to determine effects of rising CO{sub 2} on intrinsic water use efficiency (CO{sub 2} assimilation, A/stomatal conductance to water, g) of C{sub 4} plants. The increase in A/g was proportionally greater than that in CO{sub 2} from near glacial to present concentrations in the perennial grass Schizachyrium scoparium and, in one of two years, in the annual grassmore » Zea mays, because of a corresponding decrease in the ratio of leaf intercellular (c{sub i}) to external CO{sub 2} concentration (c{sub a}). Leaf A/g increased 66% in S. scoparium and 80% in the perennial shrub Atriplex canescens from 350 to 700 {mu}mol/mol CO{sub 2}, but averaged across species declined 15% from 700 to 1000 {mu}mol/mol because of an accompanying increase in c{sub i}/c{sub a}. At each CO{sub 2} level, A/g was higher in the grass than shrub. There were substantial differences in A/g at a given CO{sub 2} concentration and in the response of A/g to CO{sub 2} among the species examined. Because much of the positive response of C{sub 4} plants to CO{sub 2} derives from higher water use efficiency, these differences could influence the relative productivities of C{sub 4} species.« less

Concentration-discharge relationships for variably sized streams in Florida: Patterns and drivers in long-term catchment studies

NASA Astrophysics Data System (ADS)

Diamond, J.; Cohen, M.

2012-12-01

Catchment-scale analyses can provide important insight into the processes governing solute sources, transport and storage. Understanding solute dynamics is vital for water management both for accurate predictions of chemical fluxes as well as ecosystem responses to them. This project synthesized long-term (>15 years) hydrochemical data from 80 variably sized (101-105 m2) watersheds in Florida. Our goal was to evaluate scaling effects on flow-solute relationships, and determine the factors that control observed inter-catchment variation. We obtained long term records of a variety of chemical parameters include color, nutrients (N and P), and geogenic solutes (Ca, Si, Mg, Na, Cl) from stations where chemistry and flow data were matched. Catchment attributes (land use, terrain, surface geology) were obtained for each stream as potential covariates. Concentration-discharge relationships were modeled as power functions, the exponents (b) of which were categorized into three end-member scenarios: (1) b>0, or chemodynamic conditions, where increased discharge increases concentration, (2) b=0, or chemostatic conditions, where concentration is independent of discharge, and (3) b<0, or dilution conditions, where increased discharge decreases concentrations. Color was strongly chemodynamic, while geogenic solutes tended to be chemostatic;nutrient-flow relationships varied substantially (from dilution to chemodynamic) suggesting important ancillary controls. To assess between-site variability, power function exponents were compared against land use and catchment area. These results indicate that watersheds dominated by urban land use exhibit stronger dilution effects for most solutes while watersheds dominated by agricultural land use were generally chemostatic particularly for nutrients. This synthesis approach to understanding controls on observed concentration-discharge relationships is crucial to understanding the dynamics and early-warning indicators of anthropogenically-induced transition from dilution to chemostatic behavior.

DMSO modifies the permeability of the zebrafish (Danio rerio) chorion-implications for the fish embryo test (FET).

PubMed

Kais, B; Schneider, K E; Keiter, S; Henn, K; Ackermann, C; Braunbeck, T

2013-09-15

Since 2007, when REACH came into force, the fish embryo test has received increasing attention as a potential alternative for the acute fish test. Due to its low toxicity and the ability to permeate biological membranes without significant damage to their structural integrity, dimethyl sulfoxide (DMSO) is a commonly used solvent in the fish embryo test. Little is known, however, about the membrane penetration properties of DMSO, the impact of different concentrations of DMSO on the potential barrier function of the zebrafish chorion and on changes in the uptake of chemicals into the embryo. Therefore, in the present study, the fluorescent dyes fluorescein (mol wt 332; Pow 3.4) and 2,7-dichlorofluorescein (mol wt 401; Pow 4.7), both substances with limited water solubility, were used to visualize the uptake into the egg as well as the accumulation in the embryo of the zebrafish depending on different concentrations of DMSO. The distribution of fluorescein within the egg compartments varied with DMSO concentration: When dissolved in 0.01% DMSO, fluorescein did not pass the chorion. In contrast, concentrations ≥ 0.1% DMSO increasingly facilitated the uptake into the perivitelline space. In contrast, the uptake of 2,7-dichlorofluorescein was not substantially increased with rising DMSO concentrations, indicating the importance of factors other than the solvent (e.g. mol wt). With respect to the fish embryo test, results indicate that DMSO may be used without complications as a solvent, however, only at a maximum concentration of 0.01% (0.1 mL/L) as already indicated in the OECD difficult substances paper (OECD, 2000). Copyright © 2013 Elsevier B.V. All rights reserved.

Hydrophobic forces in thin water films stabilized by dodecylammonium chloride

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoon, R.H.; Aksoy, B.S.

1999-03-01

A thin film balance of Scheludko-Exerowa type was used to determine equilibrium film thicknesses of dodecylammonium chloride (RNH{sub 3}Cl) solutions. The data were analyzed in view of the extended DLVO theory, which considers electrostatic, van der Waals. and hydrophobic forces. The hydrophobic force was represented as a power law which is of the same form as for the van der Waals force, so that its constant K{sub 232} can be directly compared with the Hamaker constant, A{sub 232}. The results showed that at low surfactant concentrations, K{sub 232} is positive and decreases with increasing surfactant concentration, suggesting that hydrophobic forcemore » plays an important role in thin films. When the K{sub 232} versus concentration plot was extrapolated to very dilute solutions, K{sub 232} approaches 10{sup {minus}17} J, which is approximately 270 times larger than A{sub 232}. When the surfactant concentration was increased above 2 {times} 10{sup {minus}3} M, however, K{sub 232} becomes negative, indicating that hydration force appears at high surfactant concentrations. These results suggest that air bubbles are hydrophobic and the hydrophobicity decreases with increasing surfactant concentration. A TFB was used to obtain a disjoining pressure isotherm at 10{sup {minus}3} M RNH{sub 3}Cl in the presence of 10{sup {minus}4} M NaCl. The results can be fitted to the extended DLVO theory with K{sub 232} = 6 {times} 10{sup {minus}19} J. Consideration of hydrophobic force predicted a rupture thickness larger than predicted using the DLVO theory, but is substantially smaller than the experimental result. This discrepancy may be ascribed to the hydrodynamic force operating in the film thinning process.« less

The role of long-range transport and domestic emissions in determining atmospheric secondary inorganic particle concentrations across the UK

NASA Astrophysics Data System (ADS)

Vieno, M.; Heal, M. R.; Hallsworth, S.; Famulari, D.; Doherty, R. M.; Dore, A. J.; Tang, Y. S.; Braban, C. F.; Leaver, D.; Sutton, M. A.; Reis, S.

2013-12-01

Surface concentrations of secondary inorganic particle components over the UK have been analysed for 2001-2010 using the EMEP4UK regional atmospheric chemistry transport model. In early 2003 an episode of substantially elevated surface concentrations of ammonium nitrate was measured across the UK by the AGANET network. The EMEP4UK model was able accurately to represent both the long-term decadal surface concentrations and the episode in 2003. The latter was identified as consisting of three separate episodes, each of less than 1 month duration, in February, March and April. The primary cause of the elevated nitrate levels across the UK was meteorological, a persistent high pressure system, but whose varying location impacted the relative importance of transboundary vs. domestic emissions. Whilst long-range transport dominated the elevated nitrate in February, in contrast it was domestic emissions that mainly contributed to the March episode, and for the April episode both domestic emissions and long-range transport contributed. A prolonged episode such as the one in early 2003 can have substantial impact on annual average concentrations. The episode led to annual concentration differences at the regional scale of similar magnitude to those driven by long-term changes in precursor emissions over the full decade investigated here. The results demonstrate that a substantial part of the UK, particularly the south and south-east, may be close to or actually exceeding annual mean limit values because of import of inorganic aerosol components from continental Europe under specific conditions. The results reinforce the importance of employing multiple year simulations in the assessment of emissions reduction scenarios on PM concentrations and the need for international agreements to address the transboundary component of air pollution.

Excited state intramolecular charge transfer reaction in nonaqueous electrolyte solutions: Temperature dependence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pradhan, Tuhin; Gazi, Harun Al Rasid; Biswas, Ranjit

2009-08-07

Temperature dependence of the excited state intramolecular charge transfer reaction of 4-(1-azetidinyl)benzonitrile (P4C) in ethyl acetate (EA), acetonitrile (ACN), and ethanol at several concentrations of lithium perchlorate (LiClO{sub 4}) has been investigated by using the steady state and time resolved fluorescence spectroscopic techniques. The temperature range considered is 267-343 K. The temperature dependent spectral peak shifts and reaction driving force (-{Delta}G{sub r}) in electrolyte solutions of these solvents can be explained qualitatively in terms of interaction between the reactant molecule and ion-atmosphere. Time resolved studies indicate that the decay kinetics of P4C is biexponential, regardless of solvents, LiClO{sub 4} concentrations,more » and temperatures considered. Except at higher electrolyte concentrations in EA, reaction rates in solutions follow the Arrhenius-type temperature dependence where the estimated activation energy exhibits substantial electrolyte concentration dependence. The average of the experimentally measured activation energies in these three neat solvents is found to be in very good agreement with the predicted value based on data in room temperature solvents. While the rate constant in EA shows a electrolyte concentration induced parabolic dependence on reaction driving force (-{Delta}G{sub r}), the former in ethanol and ACN increases only linearly with the increase in driving force (-{Delta}G{sub r}). The data presented here also indicate that the step-wise increase in solvent reorganization energy via sequential addition of electrolyte induces the ICT reaction in weakly polar solvents to crossover from the Marcus inverted region to the normal region.« less

Intracellular Ca2+ threshold reversibly switches flagellar beat off and on.

PubMed

Sánchez-Cárdenas, C; Montoya, F; Navarrete, F A; Hernández-Cruz, A; Corkidi, G; Visconti, P E; Darszon, A

2018-06-08

Sperm motility is essential for fertilization. The asymmetry of flagellar beat in spermatozoa is finely regulated by intracellular calcium concentration ([Ca2+]i). Recently, we demonstrated that the application of high concentrations (10-20 μM) of the Ca2+ ionophore A23187 promotes sperm immobilization after 10 minutes, and its removal thereafter allows motility recovery, hyperactivation and fertilization. In addition, the same ionophore treatment overcomes infertility observed in sperm from Catsper1-/-, Slo3-/- and Adcy10-/-, but not PMCA4-/-, which strongly suggest that regulation of [Ca2+]i is mandatory for sperm motility and hyperactivation. In this study we found that prior to inducing sperm immobilization, high A23187 concentrations (10 μM) increase flagellar beat. While 5-10 μM A23187 substantially elevates [Ca2+]i and rapidly immobilizes sperm in a few minutes, smaller concentrations (0.5 and 1 μM) provoke smaller [Ca2+]i increases and sperm hyperactivation, confirming that [Ca2+]i increases act as a motility switch. Until now the [Ca2+]i thresholds that switch motility on and off were not fully understood. To study the relationship between [Ca2+]i and flagellar beating, we developed an automatic tool that allows the simultaneous measurement of these two parameters. Individual spermatozoa were treated with A23187 which is then washed to evaluate [Ca2+]i and flagellar beat recovery using the implemented method. We observe that [Ca2+]i must decrease below a threshold concentration range to facilitate subsequent flagellar beat recovery and sperm motility.

Erythrocyte sedimentation rate and fibrinogen concentration of whole blood influences the cellular composition of platelet-rich plasma obtained from centrifugation methods.

PubMed

Yin, Wenjing; Xu, Zhengliang; Sheng, Jiagen; Xie, Xuetao; Zhang, Changqing

2017-09-01

Erythrocyte sedimentation rate (ESR), which reflects the sedimentation rate of platelets, leukocytes and erythrocytes in response to centrifugal force, may influence the cellular composition of platelet-rich plasma (PRP) obtained via centrifugation methods. However, no relevant studies have substantiated this. In the present study, blood was collected from 40 healthy volunteers and used to prepare PRP with two plasma-based preparation systems [YinPRP and Plasma Rich in Growth Factor (PRGF) systems] and two buffy coat-based systems (RegenPRP and WEGOPRP systems) in a single-donor model. Volumes of PRP and platelet-poor plasma (PPP) that were removed in the preparation process were recorded. Analyses of ESR, haematocrit, C-reaction protein, coagulation, serum glucose and serum lipid of the whole blood used for PRP preparation were performed to evaluate the levels of ESR and the factors known to influence it. Whole blood analysis was performed to evaluate the cellular composition of PRP. Results demonstrated that there were marked positive correlations between the ESR of the whole blood used for PRP preparation and PPP removal efficiencies, platelet concentrations, platelet capture efficiencies and platelet enrichment factors of PRP formulations obtained from plasma-based systems, and PRP yield efficiency of RegenPRP and PPP removal efficiency of WEGOPRP. Furthermore, there were marked negative correlations between ESR and concentrations and enrichment factors of platelets, leukocytes and erythrocytes of RegenPRP. Fibrinogen concentration of the whole blood, which had a marked positive correlation with ESR, also influenced the cellular composition of PRP. These findings may increase the understanding of PRP preparation and provide substantial evidence for the individualised optimisation of PRP preparation systems used in clinical practice.

Mining legacy across a wetland landscape: high mercury in Upper Peninsula (Michigan) rivers, lakes, and fish.

PubMed

Kerfoot, W Charles; Urban, Noel R; McDonald, Cory P; Zhang, Huanxin; Rossmann, Ronald; Perlinger, Judith A; Khan, Tanvir; Hendricks, Ashley; Priyadarshini, Mugdha; Bolstad, Morgan

2018-04-25

A geographic enigma is that present-day atmospheric deposition of mercury in the Upper Peninsula of Michigan is low (48%) and that regional industrial emissions have declined substantially (ca. 81% reduction) relative to downstate. Mercury levels should be declining. However, state (MDEQ) surveys of rivers and lakes revealed elevated total mercury (THg) in Upper Peninsula waters and sediment relative to downstate. Moreover, Western Upper Peninsula (WUP) fish possess higher methyl mercury (MeHg) levels than Northern Lower Peninsula (NLP) fish. A contributing explanation for elevated THg loading is that a century ago the Upper Peninsula was a major industrial region, centered on mining. Many regional ores (silver, copper, zinc, massive sulfides) contain mercury in part per million concentrations. Copper smelters and iron furnace-taconite operations broadcast mercury almost continuously for 140 years, whereas mills discharged tailings and old mine shafts leaked contaminated water. We show that mercury emissions from copper and iron operations were substantial (60-650 kg per year) and dispersed over relatively large areas. Moreover, lake sediments in the vicinity of mining operations have higher THg concentrations. Sediment profiles from the Keweenaw Waterway show that THg accumulation increased 50- to 400-fold above modern-day atmospheric deposition levels during active mining and smelting operations, with lingering MeHg effects. High MeHg concentrations are geographically correlated with low pH and dissolved organic carbon (DOC), a consequence of biogeochemical cycling in wetlands, characteristic of the Upper Peninsula. DOC can mobilize metals and elevate MeHg concentrations. We argue that mercury loading from mining is historically superimposed upon strong regional wetland effects, producing a combined elevation of both THg and MeHg in the Western Upper Peninsula.

Effect of dietary fiber on microbial activity and microbial gas production in various regions of the gastrointestinal tract of pigs.

PubMed Central

Jensen, B B; Jørgensen, H

1994-01-01

The microbial activity, composition of the gas phase, and gas production rates in the gastrointestinal tract of pigs fed either a low- or a high-fiber diet were investigated. Dense populations of culturable anaerobic bacteria, high ATP concentrations, and high adenylate energy charges were found for the last third of the small intestine, indicating that substantial microbial activity takes place in that portion of the gut. The highest microbial activity (highest bacterium counts, highest ATP concentration, high adenylate energy charge, and low pH) was found in the cecum and proximal colon. Greater microbial activity was found in the stomach and all segments of the hindgut in the pigs fed the high-fiber diet than in the pigs fed the low-fiber diet. Considerable amounts of O2 were found in the stomach (around 5%), while the content of O2 in gas samples taken from all other parts of the gastrointestinal tract was < 1%. The highest concentrations and highest production rates for H2 were found in the last third of the small intestine. No methane could be detected in the stomach or the small intestine. The rate of production and concentration of methane in the cecum and the proximal colon were low, followed by a steady increase in the successive segments of the hindgut. A very good correlation between in vivo and in vitro measurements of methane production was found. The amount of CH4 produced by pigs fed the low-fiber diet was 1.4 liters/day per animal. Substantially larger amounts of CH4 were produced by pigs fed the high-fiber diet (12.5 liters/day)(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8031085

Effects of glucose on microcystin-LR removal and the bacterial community composition through anoxic biodegradation in drinking water sludge.

PubMed

Ma, Guangxiang; Pei, Haiyan; Hu, Wenrong; Xu, Xiangchao; Ma, Chunxia; Pei, Ruoting

2016-01-01

To enhance the degradation efficiency of microcystin (MC) in drinking water sludge (DWS), the underlying mechanisms between organic carbon (glucose) and the biodegradation of MC-LR under anoxic conditions were investigated by polymerase chain reaction-denaturing gradient gel electrophoresis technology. The addition of glucose reduced the rate of the MC-LR biodegradation indicating the occurrence of inhibition of degradation, and an increased inhibition was observed with increases in glucose concentration (0-10,000 mg/L). In addition, the community analysis indicated that the variety and the number of the microbes increased with the concentration of glucose amended (0 -1000 mg/L), but they decreased substantially with the addition of 10,000 mg/L of glucose. The phyla Firmicutes, Proteobacteria and Chloroflexi were found to be the dominant. Methylobacterium and Sphingomonas were MC-degrading bacteria and used glucose as a prior carbon source instead of MC, resulting in the decrease in the MC-LR biodegradation rate under anoxic conditions. Thus, reducing organic carbon could improve the anoxic biodegradation efficiency of MC in DWS.

High carbohydrate-low protein consumption maximizes Drosophila lifespan

PubMed Central

Bruce, Kimberley D.; Hoxha, Sany; Carvalho, Gil B.; Yamada, Ryuichi; Wang, Horng-Dar; Karayan, Paul; He, Shan; Brummel, Ted; Kapahi, Pankaj; Ja, William W.

2013-01-01

Dietary restriction extends lifespan in a variety of organisms, but the key nutritional components driving this process and how they interact remain uncertain. In Drosophila, while a substantial body of research suggests that protein is the major dietary component affecting longevity, recent studies claim that carbohydrates also play a central role. To clarify how nutritional factors influence longevity, nutrient consumption and lifespan were measured on a series of diets with varying yeast and sugar content. We show that optimal lifespan requires both high carbohydrate and low protein consumption, but neither nutrient by itself entirely predicts lifespan. Increased dietary carbohydrate or protein concentration does not always result in reduced feeding—the regulation of food consumption is best described by a constant daily caloric intake target. Moreover, due to differences in food intake, increased concentration of a nutrient within the diet does not necessarily result in increased consumption of that particular nutrient. Our results shed light on the issue of dietary effects on lifespan and highlight the need for accurate measures of nutrient intake in dietary manipulation studies. PMID:23403040

Variations in Heavy Metals Across Urban Streams

NASA Astrophysics Data System (ADS)

Kaushal, S. S.; Belt, K. T.; Stack, W. P.; Pouyat, R. V.; Groffman, P. M.; F, S. E.

2006-05-01

Urbanization has led to increased concentrations of metals such as lead (Pb), zinc (Zn), and copper (Cu) in streams due to industrial sources, domestic activities, vehicle use, and runoff from roadways. These metals can be dangerous to aquatic organisms and humans at high concentrations. We investigated variations in concentrations of heavy metals in streams across Baltimore, Maryland and within the context of convergent increases in salinity and organic carbon (two important variables that are known to affect metal transport in surface waters) due to urbanization. Despite past reductions of lead in gasoline and paints, mean concentrations of lead in some Baltimore streams were still approximately 75 micrograms/L and exceeded the U.S. EPA recommended criteria by 50 times. Mean concentrations of zinc and copper across Baltimore streams were also elevated and ranged between 15 to 140 micrograms/L and 2 to 40 micrograms/L, and mean concentrations of these metals were considerably higher than national means reported by the National Storm Water Quality database (NSWQ), which spans 3,770 storm events across the U.S. There were substantial increases in concentrations of heavy metals in streams during storms with greater than 80 percent, 70 percent, and 20 percent of storm samples exceeding recommended U.S. EPA metals criteria for Cu, Pb, and Zn respectively. Relationships between metal concentrations and stream discharge followed different patterns than nitrate and total phosphorus, other regulated pollutants in the Chesapeake Bay watershed, suggesting differences in sources and transport mechanisms within watersheds. Environmental factors such as increasing salinity from deicer use (with chloride concentrations in streams now ranging up to 5 g/L) may contribute to elevated transport of metals through ion exchange and mobilization of metals in soils and sediments. Environmental factors such as increasing organic carbon in urban streams, with ranges of 2 - 16 times greater in suburban and urban streams than forest watersheds, may also act as a vector for transporting metals due to binding capacity. Results show that metals appear to be present in harmful concentrations in many streams in Baltimore, Maryland, but further work is needed to elucidate shifts in the origin of metal pollution (storage in soils and sediments vs. roadway surfaces), and the effects of widespread changes in environmental factors that can potentially enhance their mobilization to streams.

Morphine Glucuronidation and Elimination in Intensive Care Patients: A Comparison with Healthy Volunteers.

PubMed

Ahlers, Sabine J G M; Välitalo, Pyry A J; Peeters, Mariska Y M; Gulik, Laura van; van Dongen, Eric P A; Dahan, Albert; Tibboel, Dick; Knibbe, Catherijne A J

2015-11-01

Although morphine is used frequently to treat pain in the intensive care unit, its pharmacokinetics has not been adequately quantified in critically ill patients. We evaluated the glucuronidation and elimination clearance of morphine in intensive care patients compared with healthy volunteers based on the morphine and morphine-3-glucuronide (M3G) concentrations. A population pharmacokinetic model with covariate analysis was developed with the nonlinear mixed-effects modeling software (NONMEM 7.3). The analysis included 3012 morphine and M3G concentrations from 135 intensive care patients (117 cardiothoracic surgery patients and 18 critically ill patients), who received continuous morphine infusions adapted to individual pain levels, and 622 morphine and M3G concentrations from a previously published study of 20 healthy volunteers, who received an IV bolus of morphine followed by a 1-hour infusion. For morphine, a 3-compartment model best described the data, whereas for M3G, a 1-compartment model fits best. In intensive care patients with a normal creatinine concentration, a decrease of 76% was estimated in M3G clearance compared with healthy subjects, conditional on the M3G volume of distribution being the same in intensive care patients and healthy volunteers. Furthermore, serum creatinine concentration was identified as a covariate for both elimination clearance of M3G in intensive care patients and unchanged morphine clearance in all patients and healthy volunteers. Under the assumptions in the model, M3G elimination was significantly decreased in intensive care patients when compared with healthy volunteers, which resulted in substantially increased M3G concentrations. Increased M3G levels were even more pronounced in patients with increased serum creatinine levels. Model-based simulations show that, because of the reduction in morphine clearance in intensive care patients with renal failure, a 33% reduction in the maintenance dose would result in morphine serum concentrations equal to those in healthy volunteers and intensive care patients with normal renal function, although M3G concentrations remain increased. Future pharmacodynamic investigations are needed to identify target concentrations in this population, after which final dosing recommendations can be made.

Proline Accumulation in Maize (Zea mays L.) Primary Roots at Low Water Potentials. II. Metabolic Source of Increased Proline Deposition in the Elongation Zone1

PubMed Central

Verslues, Paul E.; Sharp, Robert E.

1999-01-01

The proline (Pro) concentration increases greatly in the growing region of maize (Zea mays L.) primary roots at low water potentials (ψw), largely as a result of an increased net rate of Pro deposition. Labeled glutamate (Glu), ornithine (Orn), or Pro was supplied specifically to the root tip of intact seedlings in solution culture at high and low ψw to assess the relative importance of Pro synthesis, catabolism, utilization, and transport in root-tip Pro deposition. Labeling with [3H]Glu indicated that Pro synthesis from Glu did not increase substantially at low ψw and accounted for only a small fraction of the Pro deposition. Labeling with [14C]Orn showed that Pro synthesis from Orn also could not be a substantial contributor to Pro deposition. Labeling with [3H]Pro indicated that neither Pro catabolism nor utilization in the root tip was decreased at low ψw. Pro catabolism occurred at least as rapidly as Pro synthesis from Glu. There was, however, an increase in Pro uptake at low ψw, which suggests increased Pro transport. Taken together, the data indicate that increased transport of Pro to the root tip serves as the source of low-ψw-induced Pro accumulation. The possible significance of Pro catabolism in sustaining root growth at low ψw is also discussed. PMID:10198094

Single-crystalline oxide films of the Al2O3-Y2O3-R2O3 system as optical sensors of various types of ionizing radiation: significant advantages over volume analogs

NASA Astrophysics Data System (ADS)

Zorenko, Yuri V.; Batenchuk, M.; Gorbenco, V.; Pashkovsky, M.

1997-02-01

This investigation is dedicated to studying of peculiarities of luminescent properties of the single crystalline films (SCF) of Al2O3-Y2O3-R2O3 oxide system with alpha-Al2O3 and garnet structure, which are used as various types of ionizing radiation luminescent detectors. These peculiarities define the number of nontrivial advantages over their volume analogues. It is shown that SCF are characterized by the low concentrations of vacancy type defects and substituent defects, and the high concentration of Pb ion as dopant. This allows us to substantially increase the spatial resolution and selectivity of cathodoluminophores on the base of these compounds.

Childhood maltreatment is associated with increased risk of subclinical hypothyroidism in pregnancy.

PubMed

Moog, Nora K; Heim, Christine M; Entringer, Sonja; Kathmann, Norbert; Wadhwa, Pathik D; Buss, Claudia

2017-10-01

The critical importance of thyroid hormones for fetal development is well established. The developing fetus is dependent on the mother for adequate thyroid hormone supply, and maternal thyroid dysfunction in pregnancy may result in suboptimal fetal development. Because exposure to childhood maltreatment (CM) has been associated with thyroid dysfunction in the non-pregnant state, we sought to test the hypothesis that exposure to CM may represent a risk factor for the development of maternal hypothyroidism in pregnancy. The study was conducted in a healthy cohort of 102 pregnant mothers who were followed across the entire course of pregnancy. At each trimester thyroid-stimulating hormone (TSH) and free thyroxine (fT4) were measured in maternal serum. Experience of CM was assessed using the Childhood Trauma Questionnaire. After adjusting for potentially confounding variables, CM exposure was associated with increased TSH concentrations across pregnancy (F 1,94.6 =11.52, p=0.001) and with a 4- to 7-fold increased risk of TSH levels above the trimester-specific clinical cut-off values. Women with clinically elevated TSH concentrations did not differ in fT4 concentrations from women with normal TSH concentrations (p>0.1), suggesting subclinical hypothyroidism. Our findings suggest that there is a substantial and clinically relevant increased risk for thyroid dysfunction during pregnancy among women exposed to abuse or neglect in their childhood. This could potentially have adverse consequences for fetal brain development. Thus, these findings highlight the critical importance of considering CM exposure as a potential risk factor for (subclinical) hypothyroidism in pregnancy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reactive hydroxyl radical-driven oral bacterial inactivation by radio frequency atmospheric plasma

NASA Astrophysics Data System (ADS)

Kang, Sung Kil; Choi, Myeong Yeol; Koo, Il Gyo; Kim, Paul Y.; Kim, Yoonsun; Kim, Gon Jun; Mohamed, Abdel-Aleam H.; Collins, George J.; Lee, Jae Koo

2011-04-01

We demonstrated bacterial (Streptococcus mutans) inactivation by a radio frequency power driven atmospheric pressure plasma torch with H2O2 entrained in the feedstock gas. Optical emission spectroscopy identified substantial excited state •OH generation inside the plasma and relative •OH formation was verified by optical absorption. The bacterial inactivation rate increased with increasing •OH generation and reached a maximum 5-log10 reduction with 0.6% H2O2 vapor. Generation of large amounts of toxic ozone is drawback of plasma bacterial inactivation, thus it is significant that the ozone concentration falls within recommended safe allowable levels with addition of H2O2 vapor to the plasma.

Does Primary Productivity Turn Up the Volume? Exploring the Relationship Between Chlorophyll a and the Soundscape of Coral Reefs in the Pacific.

PubMed

Fisher-Pool, Pollyanna I; Lammers, Marc O; Gove, Jamison; Wong, Kevin B

2016-01-01

Chlorophyll is the basis for ecosystem productivity in most marine environments. We report on an ongoing effort to examine whether ambient sounds are tied to chlorophyll levels. We hypothesized that an increase in food-web available energy will be distributed across trophic levels, eventually reaching sound-producing animals and increasing acoustic levels. To test our hypothesis, we compared reef environments to explore links between soundscapes and chlorophyll a concentrations. The study sites resided in disparate oceanographic regimes that experienced substantially different oceanographic conditions. We anticipated that the results would show differing patterns of primary productivity between sites and therefore would be reflected in the soundscapes.

Bioflotation of sulfide minerals with Acidithiobacillus ferrooxidans in relation to copper activation and surface oxidation.

PubMed

Pecina-Treviño, E T; Ramos-Escobedo, G T; Gallegos-Acevedo, P M; López-Saucedo, F J; Orrantia-Borunda, E

2012-09-01

Surface oxidation of sulfides and copper (Cu) activation are 2 of the main processes that determine the efficiency of flotation. The present study was developed with the intention to ascertain the role of the phenomena in the biomodification of sulfides by Acidithiobacillus ferrooxidans culture (cells and growth media) and their impact in bioflotation. Surface characteristics of chalcopyrite, sphalerite, and pyrrhotite, alone and in mixtures, after interaction with A. ferrooxidans were evaluated. Chalcopyrite floatability was increased substantially by biomodification, while bacteria depressed pyrrhotite floatability, favoring separation. The results showed that elemental sulfur concentration increased because of the oxidation generated by bacterial cells, the effect is intensified by the Fe(III) left in the culture and by galvanic contact. Acidithiobacillus ferrooxidans culture affects the Cu activation of sphalerite. The implications of elemental sulfur concentration and Cu activation of sphalerite are key factors that must be considered for the future development of sulfide bioflotation processes, since the depressive effect of cells could be counteracted by elemental sulfur generation.

Reducing adhesion and agglomeration within a cloud of combustible particles

NASA Technical Reports Server (NTRS)

Ross, Howard D.

1988-01-01

The study of combustible particle clouds inside flame tubes is of fundamental scientific interest as well as a practical concern. Only the suspended concentration is important to the combustion process, so that assurances must be provided that a minimum of particles adheres to the tube wall. This paper demonstrates experimentally the ability to minimize adhesion and agglomeration of acoustically-mixed lycopodium particles within a 5-cm diameter lexan flame tube. The area density of particles (ADP) adhering to the wall of bare lexan tubes was measured at greater than 100 particles/sq mm. The nature of adhesion was found to be clearly electrostatic, with the ADP level aggravated by increased mixing time, vigor, and the concentration of particles. Increases in the conductivity of the air and the tube wall did not affect ADP levels substantially. However, the observed adhesion was reduced to less than 10 p/sq mm when the air was ionized by use of an alpha emitter mounted on the inner walls of the flame tube.

Retrofitting the suburbs to increase walking: evidence from a land-use-travel study.

PubMed

Boarnet, Marlon G; Joh, Kenneth; Siembab, Walter; Fulton, William; Nguyen, Mai Thi

2011-01-01

This paper reports results from a detailed travel diary survey of 2125 residents in the South Bay area of Los Angeles County - a mature, auto-oriented suburban region. Study areas were divided into four centres, typical of compact development or smart growth, and four linear, auto-oriented corridors. Results show substantial variation in the amount of walking across study areas. Trips are shorter and more likely to be via walking in centres. A key to the centres' increased walking travel is the concentration of local shopping and service destinations in a commercial core. Yet the amount of business concentration that is associated with highly pedestrian-oriented neighbourhoods is from three to four times as large as what can be supported by the local resident base, suggesting that pedestrian-oriented neighbourhoods necessarily import shopping trips, and hence driving trips, from larger surrounding catchment areas. The results suggest both land use and mobility strategies that can be appropriate for suburban regions.

Uptake and Accumulation of Pharmaceuticals in Overhead- and Surface-Irrigated Greenhouse Lettuce.

PubMed

Bhalsod, Gemini D; Chuang, Ya-Hui; Jeon, Sangho; Gui, Wenjun; Li, Hui; Ryser, Elliot T; Guber, Andrey K; Zhang, Wei

2018-01-31

Understanding the uptake and accumulation of pharmaceuticals in vegetables under typical irrigation practices is critical to risk assessment of crop irrigation with reclaimed water. This study investigated the pharmaceutical residues in greenhouse lettuce under overhead and soil-surface irrigations using pharmaceutical-contaminated water. Compared to soil-surface irrigation, overhead irrigation substantially increased the pharmaceutical residues in lettuce shoots. The increased residue levels persisted even after washing for trimethoprim, monensin sodium, and tylosin, indicating their strong sorption to the shoots. The postwashing concentrations in fresh shoots varied from 0.05 ± 0.04 μg/kg for sulfadiazine to 345 ± 139 μg/kg for carbamazepine. Root concentration factors ranged from 0.04 ± 0.14 for tylosin to 19.2 ± 15.7 for sulfamethoxazole. Translocation factors in surface-irrigated lettuce were low for sulfamethoxalzole, trimethoprim, monensin sodium, and tylosin (0.07-0.15), but high for caffeine (4.28 ± 3.01) and carbamazepine (8.15 ± 2.87). Carbamazepine was persistent in soil and hyperaccumulated in shoots.

Combinatorial approaches with selected phytochemicals to increase antibiotic efficacy against Staphylococcus aureus biofilms.

PubMed

Abreu, Ana Cristina; Saavedra, Maria José; Simões, Lúcia C; Simões, Manuel

2016-10-01

Combinations of selected phytochemicals (reserpine, pyrrolidine, quinine, morin and quercetin) with antibiotics (ciprofloxacin, tetracycline and erythromycin) were tested on the prevention and control of Staphylococcus aureus biofilms. The phytochemicals were also studied for their ability to avoid antibiotic adaptation and to inhibit antibiotic efflux pumps. Morin, pyrrolidine and quercetin at subinhibitory concentrations had significant effects in biofilm prevention and/or control when applied alone and combined with antibiotics. Synergism between antibiotics and phytochemicals was found especially against biofilms of NorA overexpressing strain S. aureus SA1199B. This strain when growing with subinhibitory concentrations of ciprofloxacin developed increased tolerance to this antibiotic. However, this was successfully reversed by quinine and morin. In addition, reserpine and quercetin showed significant efflux pump inhibition. The overall results demonstrate the role of phytochemicals in co-therapies to promote more efficient treatments and decrease antimicrobial resistance to antibiotics, with substantial effects against S. aureus in both planktonic and biofilm states.

Effects of Simulated Land-Use Changes on Water Quality of Lake Maumelle, Arkansas

USGS Publications Warehouse

Hart, Rheannon M.; Westerman, Drew A.; Petersen, James C.; Green, W. Reed; De Lanois, Jeanne L.

2011-01-01

Lake Maumelle is one of two principal drinking-water supplies for the Little Rock and North Little Rock metropolitan areas. Lake Maumelle and the Maumelle River (its primary tributary) are more pristine than most other reservoirs and streams in the region. However, as the Lake Maumelle watershed becomes increasingly more urbanized and timber harvesting becomes more frequent, concerns about the sustainability of the quality of the water supply also have increased. Two models were developed to partially address these concerns. A Hydrological Simulation Program-FORTRAN model was developed using input data collected from October 2004 through 2008. A CE-QUAL-W2 model was developed to simulate reservoir hydrodynamics and selected water quality using the simulated output from the Hydrological Simulation Program-FORTRAN model from January 2005 through 2008. The Hydrological Simulation Program-FORTRAN watershed model was calibrated to five streamflow-gaging stations, and in general, these stations characterize a range of subwatershed areas with varying land-use types. Continuous streamflow data, discrete sediment concentration data, and other discrete water-quality data were used to calibrate the Lake Maumelle Hydrological Simulation Program-FORTRAN model. The CE-QUAL-W2 reservoir model was calibrated to water-quality data and reservoir pool altitude collected during January 2005 through December 2008 at three lake stations. In general, the overall simulation for the Hydrological Simulation Program-FORTRAN and CE-UAL-W2 models matched reasonably well to the measured data. In general, simulated and measured suspended-sediment concentrations during periods of base flow (streamflows not substantially influenced by runoff) agree reasonably well for Williams Junction (with differences-simulated minus measured value-generally ranging from -14 to 19 mg/L, and percent difference-relative to the measured value-ranging from -87 to 642 percent) and Wye (differences generally ranging from -2 to 14 mg/L, -62 to 251 percent); however, the Hydrological Simulation Program-FORTRAN model generally does not match the suspended-sediment concentrations for all stations during periods of stormflow (streamflow substantially influenced by runoff). Generally, this is also the case for fecal coliform bacteria numbers and total organic carbon and nutrient concentrations. In general, water temperature and dissolved-oxygen concentration simulations followed measured seasonal trends for all stations with the largest differences occurring during periods of lowest water temperatures (for temperature) or during the periods of lowest measured dissolved-oxygen concentrations (for dissolved oxygen). For the CE-QUAL-W2 model, simulated vertical distributions of temperatures and dissolved-oxygen concentrations agreed with measured distributions even for complex temperature profiles. Considering the oligotrophic-mesotrophic (low to intermediate primary productivity and associated low nutrient concentrations) condition of Lake Maumelle, simulated algae, phosphorus, and ammonia concentrations compared well with generally low measured values.

Concentric Split Flow Filter

NASA Technical Reports Server (NTRS)

Stapleton, Thomas J. (Inventor)

2015-01-01

A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

Using models to establish the financially optimum strategy for Irish dairy farms.

PubMed

Ruelle, E; Delaby, L; Wallace, M; Shalloo, L

2018-01-01

Determining the effect of a change in management on farm with differing characteristics is a significant challenge in the evaluation of dairy systems due to the interacting components of complex biological systems. In Ireland, milk production is increasing substantially following the abolition of the European Union milk quota regime in 2015. There are 2 main ways to increase the milk production on farm (within a fixed land base): either increase the number of animals (thus increasing the stocking rate) or increase the milk production per animal through increased feeding or increased lactation length. In this study, the effect of increased concentrate feeding or an increase in grazing intensity was simulated to determine the effect on the farm system and its economic performance. Four stocking rates (2.3, 2.6, 2.9, and 3.2 cow/ha) and 5 different concentrate supplementation strategies (0, 180, 360, 600, and 900 kg of dry matter/lactation) resulting in 20 different scenarios were evaluated across different milk, concentrate, and silage purchase prices. Each simulation was run across 10 yr of meteorological data, which had been recorded over the period 2004 to 2013. Three models-the Moorepark and St Gilles grass growth model, the pasture-based herd dynamic milk model, and the Moorepark dairy systems model-were integrated and applied to simulate the different scenarios. Overall, this study has demonstrated that the most profitable scenario was a stocking rate of 2.6 cow/ha with a concentrate supplementation of 600 kg of dry matter/cow. The factor that had the greatest influence on profitability was variability of milk price. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Feed component inhibition in ethanolic fermentation by Saccharomyces cerevisiae.

PubMed

Maiorella, B L; Blanch, H W; Wilke, C R

1984-10-01

Inhibition by secondary feed components can limit productivity and restrict process options for the production of ethanol by fermentation. New fermentation processes (such as vacuum or extractive fermentation), while selectively removing ethanol, can concentrate nonmetabolized feed components in the remaining broth. Stillage recycle to reduce stillage waste treatment results in the buildup of nonmetabolized feed components. Continuous culture experiments are presented establishing an inhibition order: CaCl(2), (NH(4))(2)xSO(4) > NaCl, NH(4)Cl > KH(2)PO(4) > xylose, MgCl(2) > MgSO(4) > KCl. Reduction of the water activity alone is not an adequate predictor of the variation in inhibitory concentration among the different components tested. As a general trend, specific ethanol productivity increases and cell production decreases as inhibitors are added at higher concentration. We postulate that these results can be interpreted in terms of an increase in energy requirements for cell maintenance under hypertonic (stressed) conditions. Ion and carbohydrate transport and specific toxic effects are reviewed as they relate to the postulated inhibition mechanism. Glycerol production increases under hypertonic conditions and glycerol is postulated to function as a nontoxic osmoregulator. Calcium was the most inhibitory component tested, causing an 80%decline in cell mass production at 0.23 mol Ca(2+)/L and calcium is present at substantial concentration in many carbohydrate sources. For a typical final cane molasses feed, stillage recycle must be limited to less than onethird of the feed rate; otherwise inhibitory effects will be observed.

Impacts of Future European Emission Reductions on Aerosol Particle Number Concentrations Accounting for Effects of Ammonia, Amines, and Organic Species.

PubMed

Julin, Jan; Murphy, Benjamin N; Patoulias, David; Fountoukis, Christos; Olenius, Tinja; Pandis, Spyros N; Riipinen, Ilona

2018-01-16

Although they are currently unregulated, atmospheric ultrafine particles (<100 nm) pose health risks because of, e.g., their capability to penetrate deep into the respiratory system. Ultrafine particles, often minor contributors to atmospheric particulate mass, typically dominate aerosol particle number concentrations. We simulated the response of particle number concentrations over Europe to recent estimates of future emission reductions of aerosol particles and their precursors. We used the chemical transport model PMCAMx-UF, with novel updates including state-of-the-art descriptions of ammonia and dimethylamine new particle formation (NPF) pathways and the condensation of organic compounds onto particles. These processes had notable impacts on atmospheric particle number concentrations. All three emission scenarios (current legislation, optimized emissions, and maximum technically feasible reductions) resulted in substantial (10-50%) decreases in median particle number concentrations over Europe. Consistent reductions were predicted in Central Europe, while Northern Europe exhibited smaller reductions or even increased concentrations. Motivated by the improved NPF descriptions for ammonia and methylamines, we placed special focus on the potential to improve air quality by reducing agricultural emissions, which are a major source of these species. Agricultural emission controls showed promise in reducing ultrafine particle number concentrations, although the change is nonlinear with particle size.

Geographic Concentration of Poverty and Arteriovenous Fistula Use among ESRD Patients

PubMed Central

Wasse, Haimanot; McClellan, Ann C.; Holt, James; Krisher, Jenna; Waller, Lance A.

2010-01-01

There is substantial geographic variability in both incident and prevalent arteriovenous fistula (AVF) use among patients with ESRD. This study examined the degree to which these variations associate with poverty in the county of a patient's treatment center. We performed a cross-sectional study including 28,135 patients treated by 1127 hemodialysis centers in five ESRD networks (16 states) between June 1, 2005 and May 31, 2006. We used the 2000 U.S. Census to categorize county-level poverty and ascertained incident AVF use from the Medicare CMS 2728 form. We calculated the 30-month slope of change in AVF prevalence from monthly facility reports collected between 2003 and 2005. More than 33% of treatment centers were located in high-poverty counties. County poverty inversely associated with incident AVF use (P for trend = 0.001). In contrast, substantial increases in prevalent AVF rates from 30.9 to 38.6% (P < 0.001) among treatment centers did not associate with county poverty (P = 0.9519). In conclusion, the concentration of poverty in the county where a treatment is located associates with incident AVF use by patients with ESRD but not with subsequent improvement in AVF use among prevalent patients. These results suggest that the Medicare ESRD program may mitigate poverty effects on AVF use. PMID:20688933

Acetoacetate protects hippocampal neurons against glutamate-mediated neuronal damage during glycolysis inhibition.

PubMed

Massieu, L; Haces, M L; Montiel, T; Hernández-Fonseca, K

2003-01-01

Glucose is the main substrate that fulfills energy brain demands. However, in some circumstances, such as diabetes, starvation, during the suckling period and the ketogenic diet, brain uses the ketone bodies, acetoacetate and beta-hydroxybutyrate, as energy sources. Ketone body utilization in brain depends directly on its blood concentration, which is normally very low, but increases substantially during the conditions mentioned above. Glutamate neurotoxicity has been implicated in neurodegeneration associated with brain ischemia, hypoglycemia and cerebral trauma, conditions related to energy failure, and to elevation of glutamate extracellular levels in brain. In recent years substantial evidence favoring a close relation between glutamate neurotoxic potentiality and cellular energy levels, has been compiled. We have previously demonstrated that accumulation of extracellular glutamate after inhibition of its transporters, induces neuronal death in vivo during energy impairment induced by glycolysis inhibition. In the present study we have assessed the protective potentiality of the ketone body, acetoacetate, against glutamate-mediated neuronal damage in the hippocampus of rats chronically treated with the glycolysis inhibitor, iodoacetate, and in hippocampal cultured neurons exposed to a toxic concentration of iodoacetate. Results show that acetoacetate efficiently protects against glutamate neurotoxicity both in vivo and in vitro probably by a mechanism involving its role as an energy substrate.

Effects of mineral dust on global atmospheric nitrate concentrations

NASA Astrophysics Data System (ADS)

Karydis, V. A.; Tsimpidi, A. P.; Pozzer, A.; Astitha, M.; Lelieveld, J.

2016-02-01

This study assesses the chemical composition and global aerosol load of the major inorganic aerosol components, focusing on mineral dust and aerosol nitrate. The mineral dust aerosol components (i.e., Ca2+, Mg2+, K+, Na+) and their emissions are included in the ECHAM5/MESSy Atmospheric Chemistry model (EMAC). Gas/aerosol partitioning is simulated using the ISORROPIA-II thermodynamic equilibrium model that considers K+, Ca2+, Mg2+, NH4+, Na+, SO42-, NO3-, Cl-, and H2O aerosol components. Emissions of mineral dust are calculated online by taking into account the soil particle size distribution and chemical composition of different deserts worldwide. Presence of metallic ions can substantially affect the nitrate partitioning into the aerosol phase due to thermodynamic interactions. The model simulates highest fine aerosol nitrate concentration over urban and industrialized areas (1-3 µg m-3), while coarse aerosol nitrate is highest close to deserts (1-4 µg m-3). The influence of mineral dust on nitrate formation extends across southern Europe, western USA, and northeastern China. The tropospheric burden of aerosol nitrate increases by 44 % when considering interactions of nitrate with mineral dust. The calculated global average nitrate aerosol concentration near the surface increases by 36 %, while the coarse- and fine-mode concentrations of nitrate increase by 53 and 21 %, respectively. Other inorganic aerosol components are affected by reactive dust components as well (e.g., the tropospheric burden of chloride increases by 9 %, ammonium decreases by 41 %, and sulfate increases by 7 %). Sensitivity tests show that nitrate aerosol is most sensitive to the chemical composition of the emitted mineral dust, followed by the soil size distribution of dust particles, the magnitude of the mineral dust emissions, and the aerosol state assumption.

Assessment of the Effect of Air Pollution Controls on Trends in Shortwave Radiation over the United States from 1995 through 2010 from Multiple Observation Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gan, Chuen-Meei; Pleim, Jonathan; Mathur, Rohit

2014-02-14

Long term datasets of total (all-sky) and clear-sky downwelling shortwave (SW) radiation, cloud cover fraction (cloudiness) and aerosol optical depth (AOD) are analyzed together with aerosol concentration from several networks (e.g. SURFRAD, CASTNET, IMPROVE and ARM) in the United States (US). Seven states with varying climatology are selected to better understand the effect of aerosols and clouds on SW radiation. This analysis aims to test the hypothesis that the reductions in anthropogenic aerosol burden resulting from substantial reductions in emissions of sulfur dioxide and nitrogen oxides over the past 15 years across the US has caused an increase in surfacemore » SW radiation. We show that the total and clear-sky downwelling SW radiation from seven sites have increasing trends except Penn State which shows no tendency in clear-sky SW radiation. After investigating several confounding factors, the causes can be due to the geography of the site, aerosol distribution, heavy air traffic and increasing cloudiness. Moreover, we assess the relationship between total column AOD with surface aerosol concentration to test our hypothesis. In our findings, the trends of clear-sky SW radiation, AOD, and aerosol concentration from the sites in eastern US agree well with our hypothesis. However, the sites in western US demonstrate increasing AOD associated with mostly increasing trends in surface aerosol concentration. At these sites, the changes in aerosol burden and/or direct aerosol effects alone cannot explain the observed changes in SW radiation, but other factors need to be considered such as cloudiness, aerosol vertical profiles and elevated plumes.« less

Biochar and Glomus caledonium Influence Cd Accumulation of Upland Kangkong (Ipomoea aquatica Forsk.) Intercropped with Alfred Stonecrop (Sedum alfredii Hance)

PubMed Central

Hu, Junli; Wu, Fuyong; Wu, Shengchun; Lam, Cheung Lung; Lin, Xiangui; Wong, Ming Hung

2014-01-01

Both biochar application and mycorrhizal inoculation have been proposed to improve plant growth and alter bioaccumulation of toxic metals. A greenhouse pot trial was conducted to investigate growth and Cd accumulation of upland kangkong (Ipomoea aquatica Forsk.) intercropped with Alfred stonecrop (Sedum alfredii Hance) in a Cd-contaminated soil inoculated with Glomus caledonium and/or applied with biochar. Compared with the monocultural control, intercropping with stonecrop (IS) decreased kangkong Cd acquisition via rhizosphere competition, and also decreased kangkong yield. Gc inoculation (+M) accelerated growth and Cd acquisition of stonecrop, and hence resulted in further decreases in kangkong Cd acquisition. Regardless of IS and +M, biochar addition (+B) increased kangkong yield via elevating soil available P, and decreased soil Cd phytoavailability and kangkong Cd concentration via increasing soil pH. Compared with the control, the treatment of IS + M + B had a substantially higher kangkong yield (+25.5%) with a lower Cd concentration (−62.7%). Gc generated additive effects on soil alkalinization and Cd stabilization to biochar, causing lower DTPA-extractable (phytoavailable) Cd concentrations and post-harvest transfer risks. PMID:24728157

Should dairy be recommended as part of a healthy vegetarian diet? Point.

PubMed

Weaver, Connie M

2009-05-01

A benefit-risk evaluation of the evidence for including dairy foods in the diet is presented. For many persons dairy products provide a substantial portion of essential nutrients, but especially calcium, potassium, and magnesium. Dietary supplements and fortified foods can be alternative sources of these nutrients, although other components of dairy foods such as amino acid composition and conjugated linoleic acid may be instrumental in the benefits associated with dairy product consumption for bone health and reduced risk of stroke, metabolic syndrome, and some cancers. Newer evidence shows that protein-induced calciuria does not have a detrimental effect on net calcium retention, and the concentrations of hormones in milk are not outside of the range of endogenous concentrations. Increased dietary protein, including from milk, can elevate serum concentrations of insulin-like growth factor I, which has an unknown relation to cancer. The concern over consumption of milk leading to increased risk of prostate cancer through reduction of serum 1,25-dihydroxyvitamin D, a potent anti-prostate cancer hormone, has been resolved with new evidence that local production of this hormone is independent of diet. Overall, evidence suggests that being a lactovegetarian has greater health benefits and reduced health risks than being a vegan.

The arbuscular mycorrhizal fungus Glomus mosseae gives contradictory effects on phosphorus and arsenic acquisition by Medicago sativa Linn.

PubMed

Chen, Baodong; Xiao, Xueyi; Zhu, Yong-Guan; Smith, F Andrew; Xie, Z Miao; Smith, Sally E

2007-07-01

Mycorrhizal fungi may play an important role in protecting plants against arsenic (As) contamination. However, little is known about the direct and indirect involvement of arbuscular mycorrhizal fungi (AMF) in detoxification mechanisms. A compartmented pot cultivation system ('cross-pots') is used here to investigate the roles of AMF Glomus mosseae in plant phosphorus (P) and As acquisition by Medicago sativa, and P-As interactions. The results indicate that fungal colonization dramatically increased plant dry weight by a factor of around 6, and also substantially increased both plant P and As contents (i.e. total uptake). Irrespective of P and As addition levels, AM plants had shoot and root P concentrations 2 fold higher, but As concentrations significantly lower, than corresponding uninoculated controls. The decreased shoot As concentrations were largely due to "dilution effects" that resulted from stimulated growth of AM plants and reduced As partitioning to shoots. The study provides further evidence for the protective effects of AMF on host plants against As contamination, and have uncovered key aspects of underlying mechanisms. The possible application of AMF in remediation practices is discussed.

Source apportionment of wet-deposited atmospheric mercury in Tampa, Florida

NASA Astrophysics Data System (ADS)

Michael, Ryan; Stuart, Amy L.; Trotz, Maya A.; Akiwumi, Fenda

2016-03-01

In this paper, sources of mercury deposition to the Tampa area (Florida, USA) are investigated by analysis of one year (March 2000-March 2001) of daily wet deposition data. HYSPLIT back-trajectory modeling was performed to assess potential source locations for high versus low concentration events in data stratified by precipitation level. Positive matrix factorization (PMF) was also applied to apportion the elemental compositions from each event and to identify sources. Increased total mercury deposition was observed during summer months, corresponding to increased precipitation. However, mercury concentration in deposited samples was not strongly correlated with precipitation amount. Back-trajectories show air masses passing over Florida land in the short (12 h) and medium (24 h) term prior to deposition for high mercury concentration events. PMF results indicate that eleven factors contribute to the deposited elements in the event data. Diagnosed elemental profiles suggest the sources that contribute to mercury wet deposition at the study site are coal combustion (52% of the deposited mercury mass), municipal waste incineration (23%), medical waste incineration (19%), and crustal dust (6%). Overall, results suggest that sources local to the county and in Florida likely contributed substantially to mercury deposition at the study site, but distant sources may also contribute.

Toxic reactivity of wheat (Triticum aestivum) plants to herbicide isoproturon.

PubMed

Yin, Xiao Le; Jiang, Lei; Song, Ning Hui; Yang, Hong

2008-06-25

The herbicide isoproturon is widely used for controlling weed/grass in agricultural practice. However, the side effect of isoproturon as contaminants on crops is unknown. In this study, we investigated isoproturon-induced oxidative stress in wheat ( Triticum aestivum). The plants were grown in soils with isoproturon at 0-20 mg/kg and showed negative biological responses. The growth of wheat seedlings with isoproturon was inhibited. Chlorophyll content significantly decreased at the low concentration of isoproturon (2 mg/kg), suggesting that chlorophyll was rather sensitive to isoproturon exposure. The level of thiobarbituric acid reactive substances (TBARS), an indicator of cellular peroxidation, showed an increase, indicating oxidative damage to plants. The isoproturon-induced oxidative stress resulted in a substantial change in activities of the majority of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX). Activities of the antioxidant enzymes showed a general increase at low isoproturon concentrations and a decrease at high isoproturon concentrations. Activities of CAT in leaves showed progressive suppression under the isoproturon exposure. Analysis of nondenaturing polyacrylamide gel electrophoresis (PAGE) confirmed these results. We also tested the activity of glutathione S-transferase (GST) and observed the activity stimulated by isoproturon at 2-10 mg/kg.

Enabling the intestinal absorption of highly polar antiviral agents: ion-pair facilitated membrane permeation of zanamivir heptyl ester and guanidino oseltamivir.

PubMed

Miller, Jonathan M; Dahan, Arik; Gupta, Deepak; Varghese, Sheeba; Amidon, Gordon L

2010-08-02

Antiviral drugs often suffer from poor intestinal permeability, preventing their delivery via the oral route. The goal of this work was to enhance the intestinal absorption of the low-permeability antiviral agents zanamivir heptyl ester (ZHE) and guanidino oseltamivir (GO) utilizing an ion-pairing approach, as a critical step toward making them oral drugs. The counterion 1-hydroxy-2-naphthoic acid (HNAP) was utilized to enhance the lipophilicity and permeability of the highly polar drugs. HNAP substantially increased the log P of the drugs by up to 3.7 log units. Binding constants (K(11(aq))) of 388 M(-1) for ZHE-HNAP and 2.91 M(-1) for GO-HNAP were obtained by applying a quasi-equilibrium transport model to double-reciprocal plots of apparent octanol-buffer distribution coefficients versus HNAP concentration. HNAP enhanced the apparent permeability (P(app)) of both compounds across Caco-2 cell monolayers in a concentration-dependent manner, as substantial P(app) (0.8-3.0 x 10(-6) cm/s) was observed in the presence of 6-24 mM HNAP, whereas no detectable transport was observed without counterion. Consistent with a quasi-equilibrium transport model, a linear relationship with slope near 1 was obtained from a log-log plot of Caco-2 P(app) versus HNAP concentration, supporting the ion-pair mechanism behind the permeability enhancement. In the rat jejunal perfusion assay, the addition of HNAP failed to increase the effective permeability (P(eff)) of GO. However, the rat jejunal permeability of ZHE was significantly enhanced by the addition of HNAP in a concentration-dependent manner, from essentially zero without HNAP to 4.0 x 10(-5) cm/s with 10 mM HNAP, matching the P(eff) of the high-permeability standard metoprolol. The success of ZHE-HNAP was explained by its >100-fold stronger K(11(aq)) versus GO-HNAP, making ZHE-HNAP less prone to dissociation and ion-exchange with competing endogenous anions and able to remain intact during membrane permeation. Overall, this work presents a novel approach to enable the oral delivery of highly polar antiviral drugs, and provides new insights into the underlying mechanisms governing the success or failure of the ion-pairing strategy to increase oral absorption.

Synergistic interplay of Gβγ and phosphatidylinositol 4,5-bisphosphate dictates Kv7.4 channel activity.

PubMed

Povstyan, Oleksandr V; Barrese, Vincenzo; Stott, Jennifer B; Greenwood, Iain A

2017-02-01

Kv7.4 channels are key determinants of arterial contractility and cochlear mechanosensation that, like all Kv7 channels, have an obligatory requirement for phosphatidylinositol 4,5-bisphosphate (PIP 2 ). βγ G proteins (Gβγ) have been identified as novel positive regulators of Kv7.4. The present study ascertained whether Gβγ increased Kv7.4 open probability through an increased sensitivity to PIP 2 . In HEK cells stably expressing Kv7.4, PIP 2 or Gβγ increased open probability in a concentration dependent manner. Depleting PIP 2 prevented any Gβγ-mediated stimulation whilst an array of Gβγ inhibitors prohibited any PIP 2 -induced current enhancement. A combination of PIP 2 and Gβγ at sub-efficacious concentrations increased channel open probability considerably. The stimulatory effects of three Kv7.2-7.5 channel activators were also lost by PIP 2 depletion or Gβγ inhibitors. This study alters substantially our understanding of the fundamental processes that dictate Kv7.4 activity, revealing a more complex and subtle paradigm where the reliance on local phosphoinositide is dictated by interaction with Gβγ.

Species-specific mercury bioaccumulation in a diverse fish community.

PubMed

Donald, David B; Wissel, Björn; Anas, M U Mohamed

2015-12-01

Mercury bioaccumulation models developed for fish provide insight into the sources and transfer of Hg within ecosystems. Mercury concentrations were assessed for 16 fish species of the western reach of Lake Diefenbaker, Saskatchewan, Canada. For top predators (northern pike, Esox Lucius; walleye, Sander vitreum), Hg concentrations were positively correlated to δ(15)N, and δ(15)N to fish age, suggesting that throughout life these fish fed on organisms with increasingly higher trophic values and Hg concentrations. However, fish mass and/or age were the principal parameters related to Hg concentrations for most species. For 9 common species combined, individual variation in Hg concentration was explained in declining order of importance by fish mass, trophic position (δ(15)N), and fish age. Delta (15)N value was not the leading variable related to Hg concentration for the assemblage, probably because of the longevity of lower--trophic-level species (3 species ≥ 20 yr), substantial overlap in Hg concentration and δ(15)N values for large-bodied fish up to 3000 g, and complex relationships between Hg concentration and δ(15)N among species. These results suggest that the quantity of food (and Hg) consumed each year and converted to fish mass, the quantity of Hg bioaccumulated over years and decades, and trophic position were significant determinants of Hg concentration in Lake Diefenbaker fish. © 2015 SETAC.

AIR QUALITY OVER THE EASTERN UNITED STATES

EPA Science Inventory

Atmospheric concentrations of ozone and fine particulate matter continue to exceed their standards in many parts of the eastern United States. However, the peak concentration levels and number of ozone exceedances have decreased substantially in recent years due, in part, to the...

Sedimentation and Occurrence and Trends of Selected Chemical Constituents in Bottom Sediment, Empire Lake, Cherokee County, Kansas, 1905-2005

USGS Publications Warehouse

Juracek, Kyle E.

2006-01-01

For about 100 years (1850-1950), the Tri-State Mining District in parts of southeast Kansas, southwest Missouri, and northeast Oklahoma was one of the primary sources of lead and zinc ore in the world. The mining activity in the Tri-State District has resulted in substantial historical and ongoing input of cadmium, lead, and zinc to the environment including Empire Lake in Cherokee County, southeast Kansas. The environmental contamination caused by the decades of mining activity resulted in southeast Cherokee County being listed on the U.S. Environmental Protection Agency's National Priority List as a superfund hazardous waste site in 1983. To provide some of the information needed to support efforts to restore the ecological health of Empire Lake, a 2-year study was begun by the U.S. Geological Survey in cooperation with the U.S. Fish and Wildlife Service and the Kansas Department of Health and Environment. A combination of sediment-thickness mapping and bottom-sediment coring was used to investigate sediment deposition and the occurrence of cadmium, lead, zinc, and other selected constituents in the bottom sediment of Empire Lake. The total estimated volume and mass of bottom sediment in Empire Lake were 44 million cubic feet and 2,400 million pounds, respectively. Most of the bottom sediment was located in the main body and the Shoal Creek arm of the reservoir. Minimal sedimentation was evident in the Spring River arm of the reservoir. The total mass of cadmium, lead, and zinc in the bottom sediment of Empire Lake was estimated to be 78,000 pounds, 650,000 pounds, and 12 million pounds, respectively. In the bottom sediment of Empire Lake, cadmium concentrations ranged from 7.3 to 76 mg/kg (milligrams per kilogram) with an overall median concentration of 29 mg/kg. Compared to an estimated background concentration of 0.4 mg/kg, the historical mining activity increased the median cadmium concentration by about 7,200 percent. Lead concentrations ranged from 100 to 950 mg/kg with an overall median concentration of 270 mg/kg. Compared to an estimated background concentration of 33 mg/kg, the median lead concentration was increased by about 720 percent as a result of mining activities. The range in zinc concentrations was 1,300 to 13,000 mg/kg with an overall median concentration of 4,900 mg/kg. Compared to an estimated background concentration of 92 mg/kg, the median zinc concentration was increased by about 5,200 percent. Within Empire Lake, the largest sediment concentrations of cadmium, lead, and zinc were measured in the main body of the reservoir. Within the Spring River arm of the reservoir, increased concentrations in the downstream direction likely were the result of tributary inflow from Short Creek, which drains an area that has been substantially affected by historical lead and zinc mining. Compared to nonenforceable sediment-quality guidelines, all Empire Lake sediment samples (representing 21 coring sites) had cadmium concentrations that exceeded the probable-effects guideline (4.98 mg/kg), which represents the concentration above which toxic biological effects usually or frequently occur. With one exception, cadmium concentrations exceeded the probable-effects guideline by about 180 to about 1,400 percent. With one exception, all sediment samples had lead concentrations that exceeded the probable-effects guideline (128 mg/kg) by about 10 to about 640 percent. All sediment samples had zinc concentrations that exceeded the probable-effects guideline (459 mg/kg) by about 180 to about 2,700 percent. Overall, cadmium, lead, and zinc concentrations in the bottom sediment of Empire Lake have decreased over time following the end of lead and zinc mining in the area. However, the concentrations in the most recently deposited bottom sediment (determined for 4 of 21 coring sites) still exceeded the probable-effects guideline by about 440 to 640 percent for cadmium, about 40 to 80 percent for lead, and about 580

Concentration-Dependent Patterns of Leucine Incorporation by Coastal Picoplankton

PubMed Central

Alonso, Cecilia; Pernthaler, Jakob

2006-01-01

Coastal pelagic environments are believed to feature concentration gradients of dissolved organic carbon at a microscale, and they are characterized by pronounced seasonal differences in substrate availability for the heterotrophic picoplankton. Microbial taxa that coexist in such habitats might thus differ in their ability to incorporate substrates at various concentrations. We investigated the incorporation patterns of leucine in four microbial lineages from the coastal North Sea at concentrations between 0.1 and 100 nM before and during a spring phytoplankton bloom. Community bulk incorporation rates and the fraction of leucine-incorporating cells in the different populations were analyzed. Significantly fewer bacterial cells incorporated the amino acid before (13 to 35%) than during (23 to 47%) the bloom at all but the highest concentration. The incorporation rate per active cell in the prebloom situation was constant above 0.1 nM added leucine, whereas it increased steeply with substrate concentration during the bloom. At both time points, a high proportion of members of the Roseobacter clade incorporated leucine at all concentrations (55 to 80% and 86 to 94%, respectively). In contrast, the fractions of leucine-incorporating cells increased substantially with substrate availability in bacteria from the SAR86 clade (8 to 31%) and from DE cluster 2 of the Flavobacteria-Sphingobacteria (14 to 33%). The incorporation patterns of marine Euryarchaeota were between these extremes (30 to 56% and 48 to 70%, respectively). Our results suggest that the contribution of microbial taxa to the turnover of particular substrates may be concentration dependent. This may help us to understand the specific niches of coexisting populations that appear to compete for the same resources. PMID:16517664

Maternal transfer of mercury to songbird eggs.

PubMed

Ackerman, Joshua T; Hartman, C Alex; Herzog, Mark P

2017-11-01

We evaluated the maternal transfer of mercury to eggs in songbirds, determined whether this relationship differed between songbird species, and developed equations for predicting mercury concentrations in eggs from maternal blood. We sampled blood and feathers from 44 house wren (Troglodytes aedon) and 34 tree swallow (Tachycineta bicolor) mothers and collected their full clutches (n = 476 eggs) within 3 days of clutch completion. Additionally, we sampled blood and feathers from 53 tree swallow mothers and randomly collected one egg from their clutches (n = 53 eggs) during mid to late incubation (6-10 days incubated) to evaluate whether the relationship varied with the timing of sampling the mother's blood. Mercury concentrations in eggs were positively correlated with mercury concentrations in maternal blood sampled at (1) the time of clutch completion for both house wrens (R 2  = 0.97) and tree swallows (R 2  = 0.97) and (2) during mid to late incubation for tree swallows (R 2  = 0.71). The relationship between mercury concentrations in eggs and maternal blood did not differ with the stage of incubation when maternal blood was sampled. Importantly, the proportion of mercury transferred from mothers to their eggs decreased substantially with increasing blood mercury concentrations in tree swallows, but increased slightly with increasing blood mercury concentrations in house wrens. Additionally, the proportion of mercury transferred to eggs at the same maternal blood mercury concentration differed between species. Specifically, tree swallow mothers transferred 17%-107% more mercury to their eggs than house wren mothers over the observed mercury concentrations in maternal blood (0.15-1.92 μg/g ww). In contrast, mercury concentrations in eggs were not correlated with those in maternal feathers and, likewise, mercury concentrations in maternal blood were not correlated with those in feathers (all R 2  < 0.01). We provide equations to translate mercury concentrations from maternal blood to eggs (and vice versa), which should facilitate comparisons among studies and help integrate toxicity benchmarks into a common tissue. Published by Elsevier Ltd.

Maternal transfer of mercury to songbird eggs

USGS Publications Warehouse

Ackerman, Joshua T.; Hartman, C. Alex; Herzog, Mark

2017-01-01

We evaluated the maternal transfer of mercury to eggs in songbirds, determined whether this relationship differed between songbird species, and developed equations for predicting mercury concentrations in eggs from maternal blood. We sampled blood and feathers from 44 house wren (Troglodytes aedon) and 34 tree swallow (Tachycineta bicolor) mothers and collected their full clutches (n = 476 eggs) within 3 days of clutch completion. Additionally, we sampled blood and feathers from 53 tree swallow mothers and randomly collected one egg from their clutches (n = 53 eggs) during mid to late incubation (6–10 days incubated) to evaluate whether the relationship varied with the timing of sampling the mother's blood. Mercury concentrations in eggs were positively correlated with mercury concentrations in maternal blood sampled at (1) the time of clutch completion for both house wrens (R2 = 0.97) and tree swallows (R2 = 0.97) and (2) during mid to late incubation for tree swallows (R2 = 0.71). The relationship between mercury concentrations in eggs and maternal blood did not differ with the stage of incubation when maternal blood was sampled. Importantly, the proportion of mercury transferred from mothers to their eggs decreased substantially with increasing blood mercury concentrations in tree swallows, but increased slightly with increasing blood mercury concentrations in house wrens. Additionally, the proportion of mercury transferred to eggs at the same maternal blood mercury concentration differed between species. Specifically, tree swallow mothers transferred 17%–107% more mercury to their eggs than house wren mothers over the observed mercury concentrations in maternal blood (0.15–1.92 μg/g ww). In contrast, mercury concentrations in eggs were not correlated with those in maternal feathers and, likewise, mercury concentrations in maternal blood were not correlated with those in feathers (all R2 < 0.01). We provide equations to translate mercury concentrations from maternal blood to eggs (and vice versa), which should facilitate comparisons among studies and help integrate toxicity benchmarks into a common tissue.

Simulation of hydrodynamics, temperature, and dissolved oxygen in Table Rock Lake, Missouri, 1996-1997

USGS Publications Warehouse

Green, W. Reed; Galloway, Joel M.; Richards, Joseph M.; Wesolowski, Edwin A.

2003-01-01

Outflow from Table Rock Lake and other White River reservoirs support a cold-water trout fishery of substantial economic yield in south-central Missouri and north-central Arkansas. The Missouri Department of Conservation has requested an increase in existing minimum flows through the Table Rock Lake Dam from the U.S. Army Corps of Engineers to increase the quality of fishable waters downstream in Lake Taneycomo. Information is needed to assess the effect of increased minimum flows on temperature and dissolved- oxygen concentrations of reservoir water and the outflow. A two-dimensional, laterally averaged, hydrodynamic, temperature, and dissolved-oxygen model, CE-QUAL-W2, was developed and calibrated for Table Rock Lake, located in Missouri, north of the Arkansas-Missouri State line. The model simulates water-surface elevation, heat transport, and dissolved-oxygen dynamics. The model was developed to assess the effects of proposed increases in minimum flow from about 4.4 cubic meters per second (the existing minimum flow) to 11.3 cubic meters per second (the increased minimum flow). Simulations included assessing the effect of (1) increased minimum flows and (2) increased minimum flows with increased water-surface elevations in Table Rock Lake, on outflow temperatures and dissolved-oxygen concentrations. In both minimum flow scenarios, water temperature appeared to stay the same or increase slightly (less than 0.37 ?C) and dissolved oxygen appeared to decrease slightly (less than 0.78 mg/L) in the outflow during the thermal stratification season. However, differences between the minimum flow scenarios for water temperature and dissolved- oxygen concentration and the calibrated model were similar to the differences between measured and simulated water-column profile values.

Temporal growth factor release from platelet-rich plasma, trehalose lyophilized platelets, and bone marrow aspirate and their effect on tendon and ligament gene expression.

PubMed

McCarrel, Taralyn; Fortier, Lisa

2009-08-01

Platelet-rich plasma (PRP) has generated substantial interest for tendon and ligament regeneration because of the high concentrations of growth factors in platelet alpha-granules. This study compared the temporal release of growth factors from bone marrow aspirate (BMA), PRP, and lyophilized platelet product (PP), and measured their effects on tendon and ligament gene expression. Blood and BMA were collected and processed to yield PRP and plasma. Flexor digitorum superficialis tendon (FDS) and suspensory ligament (SL) explants were cultured in 10% plasma in DMEM (control), BMA, PRP, or PP. TGF-beta1 and PDGF-BB concentrations were determined at 0, 24, and 96 h of culture using ELISA. Quantitative RT-PCR for collagen types I and III (COL1A1, COL3A1), cartilage oligomeric matrix protein (COMP), decorin, and matrix metalloproteinases-3 and 13 (MMP-3, MMP-13) was performed. TGF-beta1 and PDGF-BB concentrations were highest in PRP and PP. Growth factor quantity was unchanged in BMA, increased in PRP, and decreased in PP over 4 days. TGF-beta1 and platelet concentrations were positively correlated. Lyophilized PP and PRP resulted in increased COL1A1:COL3A1 ratio, increased COMP, and decreased MMP-13 expression. BMA resulted in decreased COMP and increased MMP-3 and MMP-13 gene expression. Platelet concentration was positively correlated with COL1A1, ratio of COL1A1:COL3A1, and COMP, and negatively correlated with COL3A1, MMP-13, and MMP-3. White blood cell concentration was positively correlated with COL3A1, MMP3, and MMP13, and negatively correlated with a ratio of COL1A1:COL3A1, COMP, and decorin. These findings support further in vivo investigation of PRP and PP for treatment of tendonitis and desmitis. Copyright 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Cytotoxic and inflammatory effects of contact lens solutions on human corneal epithelial cells in vitro.

PubMed

Oh, Sarah; McCanna, David J; Subbaraman, Lakshman N; Jones, Lyndon W

2018-06-01

To ascertain the effect that four contact lens (CL) multipurpose solutions (MPS) have on the viability and release of pro-inflammatory cytokines from human corneal epithelial cells (HCEC). HCEC were exposed to four different MPS at various concentrations for 18 hours. The cells were also exposed to phosphate buffer, borate buffer, and PHMB. The cell viability was evaluated using the alamarBlue assay. The release of pro-inflammatory cytokines was measured using a Multiplex electrochemiluminescent assay. MPS-A, MPS-B and MPS-C all reduced cell metabolic activity p < 0.05 from control with MPS-A showing the greatest cytotoxic effect (maximum reduction, 90.6%). In contrast, MPS-D showed no significant reductions in cytotoxicity except at the highest concentration tested (19% reduction at 20% MPS concentration). Of the four cytokines evaluated MPS-C showed a substantial increase in the release of IL-1β, IL-6, IL-8, and TNF-α at higher concentrations when compared to control p < 0.05. At the 20% concentration of MPS-A and MPS-B the release of IL-1 β increased p < 0.05 but the release of IL-6, IL-8, and TNF-α decreased. MPS-D did not cause a change in the release of cytokines IL-1β, IL-6, IL-8 and TNF-α p > 0.05. Exposing the cells to borate buffer and PHMB caused an increase in the release of TNF-α p < 0.05. This investigation demonstrates that at different concentration levels, several of the MPS tested showed a decrease in viability and an increase in the release of inflammatory cytokines from HCEC. The borate buffer component as well as PHMB appears to contribute to this pro-inflammatory reaction. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Seasonal Dynamics of Glyphosate and AMPA in Lake Greifensee: Rapid Microbial Degradation in the Epilimnion During Summer.

PubMed

Huntscha, Sebastian; Stravs, Michael A; Bühlmann, Andreas; Ahrens, Christian H; Frey, Jürg E; Pomati, Francesco; Hollender, Juliane; Buerge, Ignaz J; Balmer, Marianne E; Poiger, Thomas

2018-04-17

Occurrence and fate of glyphosate, a widely used herbicide, and its main metabolite AMPA was investigated in Lake Greifensee, Switzerland. Monthly vertical concentration profiles in the lake showed an increase of glyphosate concentrations in the epilimnion from 15 ng/L in March to 145 ng/L in July, followed by a sharp decline to <5 ng/L in August. A similar pattern was observed for AMPA. Concentrations of glyphosate and AMPA in the two main tributaries generally were much higher than in the lake. Simulations using a numerical lake model indicated that a substantial amount of glyphosate and AMPA dissipated in the epilimnion, mainly in July and August, with half-lives of only ≈2-4 days which is ≫100 times faster than in the preceding months. Fast dissipation coincided with high water temperatures and phytoplankton densities, and low phosphate concentrations. This indicates that glyphosate might have been used as an alternative phosphorus source by bacterio- and phytoplankton. Metagenomic analysis of lake water revealed the presence of organisms known to be capable of degrading glyphosate and AMPA.

Orange juice substantially reduces the bioavailability of the beta-adrenergic-blocking agent celiprolol.

PubMed

Lilja, Jari J; Juntti-Patinen, Laura; Neuvonen, Pertti J

2004-03-01

Grapefruit juice was recently found to decrease plasma concentrations of the beta-adrenergic receptor-blocking agent celiprolol. Our objective was to investigate the effect of orange juice on the pharmacokinetics of celiprolol in healthy subjects. In a randomized crossover study with 2 phases and a washout of 2 weeks, 10 healthy volunteers ingested either 200 mL normal-strength orange juice or water 3 times a day for 2 days. On the morning of day 3, 1 hour after ingestion of 200 mL orange juice or water, each subject ingested 100 mg celiprolol with either 200 mL orange juice or water. In addition, 200 mL orange juice or water was ingested at 4, 10, 22, and 27 hours after celiprolol intake. The concentrations of celiprolol in plasma and its excretion into urine were measured up to 33 hours after its dosing. Systolic and diastolic blood pressures and heart rate were recorded up to 10 hours. Orange juice reduced the mean peak plasma concentration of celiprolol by 89% (P <.01) and the mean area under the plasma celiprolol concentration-time curve by 83% (P <.01). The time to peak concentration of celiprolol increased from 4 to 6 hours (P <.05), and the half-life was prolonged from 4.6 to 10.8 hours (P =.05) after ingestion of orange juice. Orange juice reduced the urinary excretion of celiprolol by 77% (P <.01). No significant differences were observed in the hemodynamic variables between the phases. Orange juice substantially reduces the bioavailability of celiprolol, but the mechanism of this interaction remains to be resolved. For example, modulation of intestinal pH and of function of transporters implicated in the absorption of celiprolol may be involved. Because of the great extent of the orange juice-celiprolol interaction and a wide use of orange juice, this interaction is likely to have clinical importance in some patients, although hemodynamic consequences were not seen in young healthy subjects.

Cloud-radiation interactions - Effects of cirrus optical thickness feedbacks

NASA Technical Reports Server (NTRS)

Somerville, Richard C. J.; Iacobellis, Sam

1987-01-01

The paper is concerned with a cloud-radiation feedback mechanism which may be an important component of the climate changes expected from increased atmospheric concentrations of carbon dioxide and other trace greenhouse gases. A major result of the study is that cirrus cloud optical thickness feedbacks may indeed tend to increase the surface warming due to trace gas increases. However, the positive feedback from cirrus appears to be generally weaker than the negative effects due to lower clouds. The results just confirm those of earlier research indicating that the net effect of cloud optical thickness feedbacks may be a negative feedback which may substantially (by a factor of about 2) reduce the surface warming due to the doubling of CO2, even in the presence of cirrus clouds.

Enzymatic adaptations to arsenic-induced oxidative stress in Zea mays and genotoxic effect of arsenic in root tips of Vicia faba and Zea mays.

PubMed

Duquesnoy, Isabelle; Champeau, Gabrielle Marie; Evray, Germaine; Ledoigt, Gérard; Piquet-Pissaloux, Agnès

2010-01-01

Agronomic plant species may display physiological and biochemical responses to oxidative stress caused by heavy metals and metalloids. Zea mays plants were grown hydroponically for eight days at different concentrations of As (0, 134 and 668 μM) and at different pH (4, 7 and 9). Metabolic variations in response to As toxicity were measured using physiological parameters and antioxidant enzymatic activities. A significant decrease in SOD activity was observed in the leaves and roots of Z. mays with the majority of As treatments. As decreased G-POX activity less in leaves than in roots. An increase in the concentration of As increased APX activity in leaves and roots, except As(V) at pH 4 and pH 9 in the leaves and As(III) at pH 9 in the roots, when there was a significant decrease in APX activity at low As concentrations. After exposure to As(V), CAT activity was the same as in the control. As(III) led to an increase in CAT activity in leaves and to a decrease in roots. With increasing concentrations of As(III), CAT activity increased in both leaves and roots whatever the pH. To obtain more detailed knowledge on the effects of arsenate and arsenite exposure on Vicia faba and Z. mays, root meristems were also examined. Roots were fed hydroponically with 134, 334, 534 and 668 μM arsenate or arsenite and 4 × 10(-3)M of maleic hydrazide as positive control, at three different pH. Physiological parameters, the mitotic index and micronuclei frequencies were evaluated in root meristems. At all three pH, the highest As(V) and As(III) concentrations induced a substantial modification in root colour, increased root thickness with stiffening, and reduced root length. High concentrations also caused a significant decrease in the mitotic index, and micronucleus chromosomic aberrations were observed in the root meristems of both species. 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Leaf fossil record suggests limited influence of atmospheric CO2 on terrestrial productivity prior to angiosperm evolution

PubMed Central

Boyce, C. Kevin; Zwieniecki, Maciej A.

2012-01-01

Declining CO2 over the Cretaceous has been suggested as an evolutionary driver of the high leaf vein densities (7–28 mm mm−2) that are unique to the angiosperms throughout all of Earth history. Photosynthetic modeling indicated the link between high vein density and productivity documented in the modern low-CO2 regime would be lost as CO2 concentrations increased but also implied that plants with very low vein densities (less than 3 mm mm−2) should experience substantial disadvantages with high CO2. Thus, the hypothesized relationship between CO2 and plant evolution can be tested through analysis of the concurrent histories of alternative lineages, because an extrinsic driver like atmospheric CO2 should affect all plants and not just the flowering plants. No such relationship is seen. Regardless of CO2 concentrations, low vein densities are equally common among nonangiosperms throughout history and common enough to include forest canopies and not just obligate shade species that will always be of limited productivity. Modeling results can be reconciled with the fossil record if maximum assimilation rates of nonflowering plants are capped well below those of flowering plants, capturing biochemical and physiological differences that would be consistent with extant plants but previously unrecognized in the fossil record. Although previous photosynthetic modeling suggested that productivity would double or triple with each Phanerozoic transition from low to high CO2, productivity changes are likely to have been limited before a substantial increase accompanying the evolution of flowering plants. PMID:22689947

Increased atmospheric ammonia over the world's major agricultural areas detected from space

NASA Astrophysics Data System (ADS)

Warner, J. X.; Dickerson, R. R.; Wei, Z.; Strow, L. L.; Wang, Y.; Liang, Q.

2017-03-01

This study provides evidence of substantial increases in atmospheric ammonia (NH3) concentrations (14 year) over several of the worlds major agricultural regions, using recently available retrievals from the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. The main sources of atmospheric NH3 are farming and animal husbandry involving reactive nitrogen ultimately derived from fertilizer use; rates of emission are also sensitive to climate change. Significant increasing trends are seen over the U.S. (2.61% yr-1), the European Union (EU) (1.83% yr-1), and China (2.27% yr-1). Over the EU, the trend results from decreased scavenging by acid aerosols. Over the U.S., the increase results from a combination of decreased chemical loss and increased soil temperatures. Over China, decreased chemical loss, increasing temperatures, and increased fertilizer use all play a role. Over South Asia, increased NH3 emissions are masked by increased SO2 and NOx emissions, leading to increased aerosol loading and adverse health effects.

Increased atmospheric ammonia over the world’s major agricultural areas detected from space

PubMed Central

Warner, J. X.; Dickerson, R. R.; Wei, Z.; Strow, L. L.; Wang, Y.; Liang, Q.

2018-01-01

This study provides evidence of substantial increases in atmospheric ammonia (NH3) concentrations (14-year) over several of the worlds major agricultural regions, using recently available retrievals from the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. The main sources of atmospheric NH3 are farming and animal husbandry involving reactive nitrogen ultimately derived from fertilizer use; rates of emission are also sensitive to climate change. Significant increasing trends are seen over the US (2.61% yr−1), the European Union (EU) (1.83% yr−1), and China (2.27% yr−1). Over the EU, the trend results from decreased scavenging by acid aerosols. Over the US, the increase results from a combination of decreased chemical loss and increased soil temperatures. Over China, decreased chemical loss, increasing temperatures, and increased fertilizer use all play a role. Over South Asia, increased NH3 emissions are masked by increased SO2 and NOx emissions, leading to increased aerosol loading and adverse health effects. PMID:29657344

Increased Atmospheric Ammonia over the World's Major Agricultural Areas Detected from Space

NASA Technical Reports Server (NTRS)

Warner, J. X.; Dickerson, R. R.; Wei, Z.; Strow, L. L.; Wang, Y.; Liang, Q.

2017-01-01

This study provides evidence of substantial increases in atmospheric ammonia (NH3) concentrations (14-year) over several of the worlds major agricultural regions, using recently available retrievals from the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. The main sources of atmospheric NH3 are farming and animal husbandry involving reactive nitrogen ultimately derived from fertilizer use; rates of emission are also sensitive to climate change. Significant increasing trends are seen over the U.S. (2.61%?per yr), the European Union (EU) (1.83%?per yr), and China (2.27%?per yr). Over the EU, the trend results from decreased scavenging by acid aerosols. Over the U.S., the increase results from a combination of decreased chemical loss and increased soil temperatures. Over China, decreased chemical loss, increasing temperatures, and increased fertilizer use all play a role. Over South Asia, increased NH3 emissions are masked by increased SO2 and NOX emissions, leading to increased aerosol loading and adverse health effects.

Changes in molecular characteristics of cereal carbohydrates after processing and digestion.

PubMed

Kasprzak, Mirosław Marek; Lærke, Helle Nygaard; Knudsen, Knud Erik Bach

2012-12-10

Different extraction, purification and digestion methods were used to investigate the molecular properties of carbohydrates in arabinoxylan and β-glucan concentrates, dietary fiber (DF) rich breads and ileum content of bread fed pigs. The breads studied were: a low DF wheat bread (WF), whole meal rye bread (GR), rye bread with kernels (RK), wheat bread supplemented with wheat arabinoxylan concentrate (AX) and wheat bread supplemented with oat β-glucan concentrate (BG). The weight average molecular weight (M(w)) of extractable carbohydrates in β-glucan concentrate decreased eight-fold after inclusion in the BG bread when exposed to in vitro digestion, while the M(w) of purified extractable carbohydrates in AX bread was reduced two-fold, and remained almost unaffected until reaching the terminal ileum of pigs. Similarly, the M(w) of purified extractable carbohydrates in GR and RK bread was not significantly changed in the ileum. The AX bread resulted in the highest concentration of dissolved arabinoxylan in the ileum among all the breads that caused a substantial increased in ileal AX viscosity. Nevertheless, for none of the breads, the M(w) of extractable carbohydrates was related neither to the bread extract nor ileal viscosity.

The stressed student: influence of written examinations and oral presentations on salivary cortisol concentrations in university students.

PubMed

Preuss, Diana; Schoofs, Daniela; Schlotz, Wolff; Wolf, Oliver T

2010-05-01

Laboratory research has demonstrated that social-evaluative threat has an influence on the hypothalamus pituitary adrenal axis (HPA). In two studies using independent samples, we evaluated the anticipatory cortisol response to a written university examination (n = 35) and to an oral presentation (n = 34). Saliva samples were collected before and after the examinations and on a control day. Additionally, saliva samples were collected on the day before the written examination and a control day. Results revealed significantly elevated cortisol concentrations on the day prior to the examination; however, this effect occurred only in those participants who had their control day after the examination. Cortisol concentrations were elevated on the examination day, with increased concentrations before but not after the examination. For the oral presentation study, the results revealed substantially elevated cortisol concentrations before and after the oral presentation. Taken together the results indicate that written examinations cause a mild anticipatory HPA response while oral presentations induce a strong HPA response. These findings appear to support the idea that social-evaluative threat is an important factor determining the size of the HPA response to laboratory stressors as well as to real-life stressors.

Changes in Molecular Characteristics of Cereal Carbohydrates after Processing and Digestion

PubMed Central

Kasprzak, Mirosław Marek; Lærke, Helle Nygaard; Knudsen, Knud Erik Bach

2012-01-01

Different extraction, purification and digestion methods were used to investigate the molecular properties of carbohydrates in arabinoxylan and β-glucan concentrates, dietary fiber (DF) rich breads and ileum content of bread fed pigs. The breads studied were: a low DF wheat bread (WF), whole meal rye bread (GR), rye bread with kernels (RK), wheat bread supplemented with wheat arabinoxylan concentrate (AX) and wheat bread supplemented with oat β-glucan concentrate (BG). The weight average molecular weight (Mw) of extractable carbohydrates in β-glucan concentrate decreased eight-fold after inclusion in the BG bread when exposed to in vitro digestion, while the Mw of purified extractable carbohydrates in AX bread was reduced two-fold, and remained almost unaffected until reaching the terminal ileum of pigs. Similarly, the Mw of purified extractable carbohydrates in GR and RK bread was not significantly changed in the ileum. The AX bread resulted in the highest concentration of dissolved arabinoxylan in the ileum among all the breads that caused a substantial increased in ileal AX viscosity. Nevertheless, for none of the breads, the Mw of extractable carbohydrates was related neither to the bread extract nor ileal viscosity. PMID:23222731

Exposure to Airborne Particles and Volatile Organic Compounds from Polyurethane Molding, Spray Painting, Lacquering, and Gluing in a Workshop

PubMed Central

Mølgaard, Bjarke; Viitanen, Anna-Kaisa; Kangas, Anneli; Huhtiniemi, Marika; Larsen, Søren Thor; Vanhala, Esa; Hussein, Tareq; Boor, Brandon E.; Hämeri, Kaarle; Koivisto, Antti Joonas

2015-01-01

Due to the health risk related to occupational air pollution exposure, we assessed concentrations and identified sources of particles and volatile organic compounds (VOCs) in a handcraft workshop producing fishing lures. The work processes in the site included polyurethane molding, spray painting, lacquering, and gluing. We measured total VOC (TVOC) concentrations and particle size distributions at three locations representing the various phases of the manufacturing and assembly process. The mean working-hour TVOC concentrations in three locations studied were 41, 37, and 24 ppm according to photo-ionization detector measurements. The mean working-hour particle number concentration varied between locations from 3000 to 36,000 cm−3. Analysis of temporal and spatial variations of TVOC concentrations revealed that there were at least four substantial VOC sources: spray gluing, mold-release agent spraying, continuous evaporation from various lacquer and paint containers, and either spray painting or lacquering (probably both). The mold-release agent spray was indirectly also a major source of ultrafine particles. The workers’ exposure can be reduced by improving the local exhaust ventilation at the known sources and by increasing the ventilation rate in the area with the continuous source. PMID:25849539

Stimulated Leaf Dark Respiration in Tomato in an Elevated Carbon Dioxide Atmosphere

PubMed Central

Li, Xin; Zhang, Guanqun; Sun, Bo; Zhang, Shuai; Zhang, Yiqing; Liao, Yangwenke; Zhou, Yanhong; Xia, Xiaojian; Shi, Kai; Yu, Jingquan

2013-01-01

It is widely accepted that leaf dark respiration is a determining factor for the growth and maintenance of plant tissues and the carbon cycle. However, the underlying effect and mechanism of elevated CO2 concentrations ([CO2]) on dark respiration remain unclear. In this study, tomato plants grown at elevated [CO2] showed consistently higher leaf dark respiratory rate, as compared with ambient control plants. The increased respiratory capacity was driven by a greater abundance of proteins, carbohydrates, and transcripts involved in pathways of glycolysis carbohydrate metabolism, the tricarboxylic acid cycle, and mitochondrial electron transport energy metabolism. This study provides substantial evidence in support of the concept that leaf dark respiration is increased by elevated [CO2] in tomato plants and suggests that the increased availability of carbohydrates and the increased energy status are involved in the increased rate of dark respiration in response to elevated [CO2]. PMID:24305603

Impacts of the large increase in international ship traffic 2000-2007 on tropospheric ozone and methane.

PubMed

Dalsøren, Stig B; Eide, Magnus S; Myhre, Gunnar; Endresen, Oyvind; Isaksen, Ivar S A; Fuglestvedt, Jan S

2010-04-01

The increase in civil world fleet ship emissions during the period 2000-2007 and the effects on key tropospheric oxidants are quantified using a global Chemical Transport Model (CTM). We estimate a substantial increase of 33% in global ship emissions over this period. The impact of ship emissions on tropospheric oxidants is mainly caused by the relatively large fraction of NOx in ship exhaust. Typical increases in yearly average surface ozone concentrations in the most impacted areas are 0.5-2.5 ppbv. The global annual mean radiative forcing due to ozone increases in the troposphere is 10 mWm(-2) over the period 2000-2007. We find global average tropospheric OH increase of 1.03% over the same period. As a result of this the global average tropospheric methane concentration is reduced by approximately 2.2% over a period corresponding to the turnover time. The resulting methane radiative forcing is -14 mWm(-2) with an additional contribution of -6 mWm(-2) from methane induced reduction in ozone. The net forcing of the ozone and methane changes due to ship emissions changes between 2000 and 2007 is -10 mWm(-2). This is significant compared to the net forcing of these components in 2000. Our findings support earlier observational studies indicating that ship traffic may be a major contributor to recent enhancement of background ozone at some coastal stations. Furthermore, by reducing global mean tropospheric methane by 40 ppbv over its turnover time it is likely to contribute to the recent observed leveling off in global mean methane concentration.

Endocrine and metabolic effects of consuming beverages sweetened with fructose, glucose, sucrose, or high-fructose corn syrup.

PubMed

Stanhope, Kimber L; Havel, Peter J

2008-12-01

Our laboratory has investigated 2 hypotheses regarding the effects of fructose consumption: 1) the endocrine effects of fructose consumption favor a positive energy balance, and 2) fructose consumption promotes the development of an atherogenic lipid profile. In previous short- and long-term studies, we showed that consumption of fructose-sweetened beverages with 3 meals results in lower 24-h plasma concentrations of glucose, insulin, and leptin in humans than does consumption of glucose-sweetened beverages. We have also tested whether prolonged consumption of high-fructose diets leads to increased caloric intake or decreased energy expenditure, thereby contributing to weight gain and obesity. Results from a study conducted in rhesus monkeys produced equivocal results. Carefully controlled and adequately powered long-term studies are needed to address these hypotheses. In both short- and long-term studies, we showed that consumption of fructose-sweetened beverages substantially increases postprandial triacylglycerol concentrations compared with glucose-sweetened beverages. In the long-term studies, apolipoprotein B concentrations were also increased in subjects consuming fructose, but not in those consuming glucose. Data from a short-term study comparing consumption of beverages sweetened with fructose, glucose, high-fructose corn syrup, and sucrose suggest that high-fructose corn syrup and sucrose increase postprandial triacylglycerol to an extent comparable with that induced by 100% fructose alone. Increased consumption of fructose-sweetened beverages along with increased prevalence of obesity, metabolic syndrome, and type 2 diabetes underscore the importance of investigating the metabolic consequences of fructose consumption in carefully controlled experiments.

Relations of changes in wastewater-treatment practices to changes in stream-water quality during 1978-88 in the Chicago area, Illinois, and implications for regional and national water-quality assessments

USGS Publications Warehouse

Terrio, P.J.

1994-01-01

A study in the upper Illinois River Basin defined relations between changes in wastewater-treatment practices and changes in stream-water quality on the basis of available information. These relations were examined for five large wastewater-treatment plants in the Chicago area, Illinois. At the three largest treatment plants, two major changes in wastewater-treatment practices were identified--the cessation of chlorination and the implementation of Chicago's Tunnel and Reservoir Plan (TARP). Other changes, such as improved aeration and expansion of the facilities, also were made at some of the treatment plants. At the Calumet Water Reclamation Plant, median densities of fecal coliform bacteria in the effluent increased from 3,100 to 1,200,000 colonies per 100 milliliters after the cessation of chlorination. Median densities at the nearest downstream monitoring site increased from 9,500 to 250,000 colonies per 100 milliliters. Similar changes in bacteria densities were indicated for other treatment plants and stream-monitoring sites, but increases in densities of fecal coliform bacteria were not indicated at distances greater than 7 miles downstream. Substantial changes in effluent and stream-water quality, primarily improvements, were identified after the implemen- of TARP and improvements in aeration. Decreases in some of the largest concentrations of ammonia were particularly notable and were likely results of the cape and treatment of combined sewer overflows by TARP. Improvements in water quality were commonly related to climatic season, with greater changes taking place during warm periods. Substantial decreases in concentrations were identified for many constituents, including oxygen demand, ammonia, bacteria, and cyanide. The water-quality data available for this study were considered to be more accurate and were more comprehensive than data from most other monitoring programs. The results of this study, however, identified some needed enhancements to increase the usefulness of the data for additional purposes and analyses.

Quantity, composition and water contamination potential of ash produced under different wildfire severities.

PubMed

Santín, Cristina; Doerr, Stefan H; Otero, Xosé L; Chafer, Chris J

2015-10-01

Wildfires frequently threaten water quality through the transfer of eroded ash and soil into rivers and reservoirs. The ability to anticipate risks for water resources from wildfires is fundamental for implementing effective fire preparedness plans and post-fire mitigation measures. Here we present a new approach that allows quantifying the amount and characteristics of ash generated under different wildfire severities and its respective water contamination potential. This approach is applied to a wildfire in an Australian dry sclerophyll eucalypt forest, but can be adapted for use in other environments. The Balmoral fire of October 2013 affected 12,694 ha of Sydney's forested water supply catchment. It produced substantial ash loads that increased with fire severity, with 6, 16 and 34 Mg ha(-1) found in areas affected by low, high and extreme fire severity, respectively. Ash bulk density was also positively related to fire severity. The increase with fire severity in the total load and bulk density of the ash generated is mainly attributed to a combination of associated increases in (i) total amount of fuel affected by fire and (ii) contribution of charred mineral soil to the ash layer. Total concentrations of pollutants and nutrients in ash were mostly unrelated to fire severity and relatively low compared to values reported for wildfire ash in other environments (e.g. 4.0-7.3mg As kg(-1); 2.3-4.1 B mg kg(-1); 136-154 P mg kg(-1)). Solubility of the elements analysed was also low, less than 10% of the total concentration for all elements except for B (6-14%) and Na (30-50%). This could be related to a partial loss of soluble components by leaching and/or wind erosion before the ash sampling (10 weeks after the fire and before major ash mobilisation by water erosion). Even with their relatively low concentrations of potential pollutants, the substantial total ash loads found here represent a water contamination risk if transported into the hydrological network during severe erosion events. For example, up to 4 Mg of ash-derived P could be delivered into a single water supply reservoir. Copyright © 2015 Elsevier Inc. All rights reserved.

Top-down regulation, climate and multi-decadal changes in coastal zoobenthos communities in two Baltic Sea areas.

PubMed

Olsson, Jens; Bergström, Lena; Gårdmark, Anna

2013-01-01

The structure of many marine ecosystems has changed substantially during recent decades, as a result of overexploitation, climate change and eutrophication. Despite of the apparent ecological and economical importance of coastal areas and communities, this aspect has received relatively little attention in coastal systems. Here we assess the temporal development of zoobenthos communities in two areas on the Swedish Baltic Sea coast during 30 years, and relate their development to changes in climate, eutrophication and top-down regulation from fish. Both communities show substantial structural changes, with a decrease in marine polychaetes and species sensitive to increased water temperatures. Concurrently, opportunistic species tolerant to environmental perturbation have increased in abundance. Species composition show a similar temporal development in both communities and significant changes in species composition occurred in both data sets in the late 1980s and early 1990s. The change in species composition was associated with large scale changes in climate (salinity and water temperature) and to the structure of the local fish community, whereas we found no effects of nutrient loading or ambient nutrient concentrations. Our results suggest that these coastal zoobenthos communities have gone through substantial structural changes over the last 30 years, resulting in communities of different species composition with potentially different ecological functions. We hence suggest that the temporal development of coastal zoobenthos communities should be assessed in light of prevailing climatic conditions considering the potential for top-down effects exerted by local fish communities.

Top-Down Regulation, Climate and Multi-Decadal Changes in Coastal Zoobenthos Communities in Two Baltic Sea Areas

PubMed Central

Olsson, Jens; Bergström, Lena; Gårdmark, Anna

2013-01-01

The structure of many marine ecosystems has changed substantially during recent decades, as a result of overexploitation, climate change and eutrophication. Despite of the apparent ecological and economical importance of coastal areas and communities, this aspect has received relatively little attention in coastal systems. Here we assess the temporal development of zoobenthos communities in two areas on the Swedish Baltic Sea coast during 30 years, and relate their development to changes in climate, eutrophication and top-down regulation from fish. Both communities show substantial structural changes, with a decrease in marine polychaetes and species sensitive to increased water temperatures. Concurrently, opportunistic species tolerant to environmental perturbation have increased in abundance. Species composition show a similar temporal development in both communities and significant changes in species composition occurred in both data sets in the late 1980s and early 1990s. The change in species composition was associated with large scale changes in climate (salinity and water temperature) and to the structure of the local fish community, whereas we found no effects of nutrient loading or ambient nutrient concentrations. Our results suggest that these coastal zoobenthos communities have gone through substantial structural changes over the last 30 years, resulting in communities of different species composition with potentially different ecological functions. We hence suggest that the temporal development of coastal zoobenthos communities should be assessed in light of prevailing climatic conditions considering the potential for top-down effects exerted by local fish communities. PMID:23737998

Relationship between venetoclax exposure, rituximab coadministration, and progression-free survival in patients with relapsed or refractory chronic lymphocytic leukemia: demonstration of synergy.

PubMed

Freise, Kevin J; Jones, Aksana K; Menon, Rajeev M; Verdugo, Maria E; Humerickhouse, Rod A; Awni, Walid M; Salem, Ahmed Hamed

2017-12-01

Venetoclax is indicated at a dosage of 400 mg daily (QD) for the treatment of patients with chronic lymphocytic leukemia (CLL) with 17p deletion who have received at least 1 prior therapy. Ongoing trials are evaluating venetoclax in combination with CD20 targeting monoclonal antibodies, such as rituximab. The objective of this research was to characterize the relationship between venetoclax exposures and progression-free survival (PFS) and to evaluate the effect of rituximab coadministration on PFS in patients with relapsed or refractory (R/R) CLL/small lymphocytic lymphoma (SLL). A total of 323 patients from 3 clinical studies of venetoclax, with and without rituximab coadministration, were pooled for the analyses. A time-variant relative risk survival model was used to relate plasma venetoclax concentrations and rituximab administration to PFS. Demographics and baseline disease characteristics were evaluated for their effect on PFS. A concentration-dependent effect of venetoclax on PFS and a prolonged synergistic effect of 6 cycles of concomitant rituximab were identified. The 17p deletion chromosomal aberration was not identified to affect the PFS of patients treated with venetoclax. A venetoclax dose of 400 mg daily QD was estimated to result in a substantial median PFS of 1.8 years (95% confidence interval [CI], 1.7-2.1), whereas the addition of 6 cycles of rituximab was estimated to increase the median PFS to 3.9 years (95% CI, 2.8-5.6). The analysis demonstrates a concentration-dependent effect of venetoclax on PFS and also a synergistic effect with rituximab. Combining venetoclax with the CD20 targeting monoclonal antibody rituximab in R/R CLL/SLL patients provides substantial synergistic benefit compared with increasing the venetoclax monotherapy dose. Copyright © 2016 John Wiley & Sons, Ltd.

Quantifying and Valuing Potential Climate Change Impacts on Coral Reefs in the United States

NASA Astrophysics Data System (ADS)

Wobus, C. W.; Lane, D.; Buddemeier, R. W.; Ready, R. C.; Shouse, K. C.; Martinich, J.

2012-12-01

Global climate change presents a two-pronged threat to coral reef ecosystems: increasing sea surface temperatures will increase the likelihood of episodic bleaching events, while increasing ocean carbon dioxide concentrations will change the carbonate chemistry that drives coral growth. Because coral reefs have important societal as well as ecological benefits, climate change mitigation policies that ameliorate these impacts may create substantial economic value. We present a model that evaluates both the ecological and the economic impacts of climate change on coral reefs in the United States. We use a coral reef mortality and bleaching model to project future coral reef declines under a range of climate change policy scenarios for south Florida, Puerto Rico and Hawaii. Using a benefits transfer approach, the outputs from the physical model are then used to quantify the economic impacts of these coral reef declines for each of these regions. We find that differing climate change trajectories create substantial changes in projected coral cover and value for Hawaii, but that the ecological and economic benefits of more stringent emissions scenarios are less clear for Florida and Puerto Rico. Overall, our results indicate that the effectiveness of climate change mitigation policies may be region-specific, but that these policies could result in a net increase of nearly $10 billion in economic value from coral reef-related recreational activities alone, over the 21st century.

Investigation of Ground-Water Contamination at Solid Waste Management Unit 12, Naval Weapons Station Charleston, North Charleston, South Carolina

USGS Publications Warehouse

Vroblesky, Don A.; Casey, Clifton C.; Petkewich, Matthew D.; Lowery, Mark A.; Conlon, Kevin J.; Harrelson, Larry G.

2007-01-01

The U.S. Geological Survey and the Naval Facilities Engineering Command Southeast investigated natural and engineered remediation of chlorinated volatile organic compound ground-water contamination at Solid Waste Management Unit 12 at the Naval Weapons Station Charleston, North Charleston, South Carolina. The primary contaminants of interest are tetrachloroethene, 1,1,1-trichloroethane, trichloroethene, cis-1,2-dichloroethene, vinyl chloride, 1,1-dichloroethane, and 1,1-dichloroethene. In general, the hydrogeology of Solid Waste Management Unit 12 consists of a surficial aquifer, composed of sand to clayey sand, overlain by dense clay that extends from about land surface to a depth of about 8 to 10 feet and substantially limits local recharge. During some months in the summer, evapotranspiration and limited local recharge result in ground-water level depressions in the forested area near wells 12MW-12S and 12MW-17S, seasonally reflecting the effects of evapotranspiration. Changes in surface-water levels following Hurricane Gaston in 2004 resulted in a substantial change in the ground-water levels at the site that, in turn, may have caused lateral shifting of the contaminant plume. Hydraulic conductivity, determined by slug tests, is higher along the axis of the plume in the downgradient part of the forests than adjacent to the plume, implying that there is some degree of lithologic control on the plume location. Hydraulic conductivity, hydraulic gradient, sulfur-hexafluoride measurements, and historical data indicate that ground-water flow rates are substantially slower in the forested area relative to upgradient areas. The ground-water contamination, consisting of chlorinated volatile organic compounds, extends eastward in the surficial aquifer from the probable source area near a former underground storage tank. Engineered remediation approaches include a permeable reactive barrier and phytoremediation. The central part of the permeable reactive barrier along the main axis of the contaminant plume appears to be actively removing contamination; however, ground-water contamination is moving around the southern end of the permeable reactive barrier. Changes in the contaminant concentrations along the path of ground-water transport reflect a complex variety of influences. Potential influences include dechlorination, sorption and desorption, transpirative removal by trees, lateral shifting of the plume, and the presence of zones of differing concentrations possibly reflecting one or more pulse releases of contamination from the source area. Near the source area at well 12MW-10S, volatile organic compound concentrations of cis-1,2-dichlorothene, vinyl chloride, 1,1-dichloroethane, and 1,1,1-trichloroethane continued an irregular decline, while tetrachloroethene and 1,1-dichloroethene showed marked fluctuations in concentration during 2005 and 2006. Volatile organic compound concentrations at well 12MW-03S continued to show decreasing concentrations with the June 2006 concentrations being the lowest yet recorded at that well for several volatile organic compounds. Concentration and delta carbon 13 data indicate that in the upgradient part of the plume, tetrachloroethene is being degraded to trichloroethene, which is being degraded to cis-1,2-dichloroethene, and cis-1,2-dichloroethene is accumulating faster than it is being depleted. Ground-water volatile organic compound concentrations also changed in some wells in the forested area in the midpart of the plume. Increasing tetrachloroethene and decreasing trichloroethene and 1,1-dichloroethene concentrations were observed at wells 12MW-05S and 12MW-29S, possibly reflecting a lateral shift in the axis of the contamination plume or an advancing contamination pulse. Substantial decreases in contamination occur in the forested area downgradient from well 12MW-05S. Probable major loss mechanisms in this area include evapotranspiration and sorption.

Biogeochemical effects of forest vegetation on acid precipitation-related water chemistry: a case study in southwest China.

PubMed

Chen, Jing; Li, Wei; Gao, Fang

2010-10-06

The elemental composition of rainwater, throughfall, and soil solutions of a forest ecosystem in the acid rain control region of southwest China was investigated during 2007-2008 to assess the acid buffering capacity of different forest covers. A possible seasonal distribution of wet deposition was identified. Sulfur was determined as the dominant acidification precursor in this region. The chemical composition of rainfall intercepted by the forest canopy was modified substantially; generally the ion concentrations were increased by dry deposition and foliar leaching. As an exception, the concentration of NH(4)(+) and NO(3)(-) decreased in throughfall, which was probably due to the absorption of nitrogen by the leaves. Elemental concentrations in soil solutions decreased with depth. The water conservation capacity of different forests was also evaluated. The most appropriate forest vegetation for water conservation and remediation of acid precipitation in this region was explored for the sake of ecosystem management, ecological restoration and economic development.

Partial nitrification in an air-lift reactor with long-term feeding of increasing ammonium concentrations.

PubMed

Chai, Li-Yuan; Ali, Mohammad; Min, Xiao-Bo; Song, Yu-Xia; Tang, Chong-Jian; Wang, Hai-Ying; Yu, Cheng; Yang, Zhi-Hui

2015-06-01

The partial nitrification (PN) performance under high ammonium concentrations was evaluated in an airlift reactor (ALR). The ALR was operated for 253days with stepwise elevation of ammonium concentration to 1400mg/L corresponding nitrogen loading rate of 2.1kg/m(3)/d. The ammonium removal rate was finally developed to 2.0kg/m(3)/d with average removal efficiency above 91% and nitrite accumulation percentage of 80%. Results showed that the combined effect of limited DO, high bicarbonate, pH and free ammonia (FA) contributed to the stable nitrite accumulation substantially. The biomass in the ALR was improved with the inception of granulation. Precipitates on biomass surface was unexpectedly experienced which might improve the settleability of PN biomass. Organic functional groups attached to the PN biomass suggested the possible absorbability to different types of pollutant. The results provided important evidence for the possibility of applying an ALR to treat high strength ammonium wastewater. Copyright © 2015 Elsevier Ltd. All rights reserved.

Production of Protein Concentrate and 1,3-Propanediol by Wheat-Based Thin Stillage Fermentation.

PubMed

Ratanapariyanuch, Kornsulee; Shim, Youn Young; Emami, Shahram; Reaney, Martin J T

2017-05-17

Fermentation of wheat with yeast produces thin stillage (W-TS) and distiller's wet grains. A subsequent fermentation of W-TS (two-stage fermentation, TSF) with endemic bacteria at 25 and 37 °C decreased glycerol and lactic acid concentrations, while 1,3-propanediol (1,3-PD) and acetic acid accumulated with greater 1,3-PD and acetic acid produced at 37 °C. During TSF, W-TS colloids coagulated and floated in the fermentation medium producing separable liquid and slurry fractions. The predominant endemic bacteria in W-TS were Lactobacillus panis, L. gallinarum, and L. helveticus, and this makeup did not change substantially as fermentation progressed. As nutrients were exhausted, floating particles precipitated. Protein contents of slurry and clarified liquid increased and decreased, respectively, as TSF progressed. The liquid was easily filtered through an ultrafiltration membrane. These results suggested that TSF is a novel method for W-TS clarification and production of protein concentrates and 1,3-PD from W-TS.

Effectiveness of in-room air filtration and dilution ventilation for tuberculosis infection control.

PubMed

Miller-Leiden, S; Lobascio, C; Nazaroff, W W; Macher, J M

1996-09-01

Tuberculosis (TB) is a public health problem that may pose substantial risks to health care workers and others. TB infection occurs by inhalation of airborne bacteria emitted by persons with active disease. We experimentally evaluated the effectiveness of in-room air filtration systems, specifically portable air filters (PAFs) and ceiling-mounted air filters (CMAFs), in conjunction with dilution ventilation, for controlling TB exposure in high-risk settings. For each experiment, a test aerosol was continuously generated and released into a full-sized room. With the in-room air filter and room ventilation system operating, time-averaged airborne particle concentrations were measured at several points. The effectiveness of in-room air filtration plus ventilation was determined by comparing particle concentrations with and without device operation. The four PAFs and three CMAFs we evaluated reduced room-average particle concentrations, typically by 30% to 90%, relative to a baseline scenario with two air-changes per hour of ventilation (outside air) only. Increasing the rate of air flow recirculating through the filter and/or air flow from the ventilation did not always increase effectiveness. Concentrations were generally higher near the emission source than elsewhere in the room. Both the air flow configuration of the filter and its placement within the room were important, influencing room air flow patterns and the spatial distribution of concentrations. Air filters containing efficient, but non-high efficiency particulate air (HEPA) filter media were as effective as air filters containing HEPA filter media.

Effectiveness of In-Room Air Filtration and Dilution Ventilation for Tuberculosis Infection Control.

PubMed

Miller-Leiden, S; Lohascio, C; Nazaroff, W W; Macher, J M

1996-09-01

Tuberculosis (TB) is a public health problem that may pose substantial risks to health care workers and others. TB infection occurs by inhalation of airborne bacteria emitted by persons with active disease. We experimentally evaluated the effectiveness of in-room air filtration systems, specifically portable air filters (PAFs) and ceiling-mounted air filters (CMAFs), in conjunction with dilution ventilation, for controlling TB exposure in high-risk settings. For each experiment, a test aerosol was continuously generated and released into a full-sized room. With the in-room air filter and room ventilation system operating, time-averaged airborne particle concentrations were measured at several points. The effectiveness of in-room air filtration plus ventilation was determined by comparing particle concentrations with and without device operation. The four PAFs and three CMAFs we evaluated reduced room-average particle concentrations, typically by 30% to 90%, relative to a baseline scenario with two air-changes per hour of ventilation (outside air) only. Increasing the rate of air flow recirculating through the filter and/or air flow from the ventilation did not always increase effectiveness. Concentrations were generally higher near the emission source than elsewhere in the room. Both the air flow configuration of the filter and its placement within the room were important, influencing room air flow patterns and the spatial distribution of concentrations. Air filters containing efficient, but non-high efficiency particulate air (HEPA) filter media were as effective as air filters containing HEPA filter media.

Fructose replacement of glucose or sucrose in food or beverages lowers postprandial glucose and insulin without raising triglycerides: a systematic review and meta-analysis.

PubMed

Evans, Rebecca A; Frese, Michael; Romero, Julio; Cunningham, Judy H; Mills, Kerry E

2017-08-01

Background: Conflicting evidence exists on the effects of fructose consumption in people with type 1 and type 2 diabetes mellitus. No systematic review has addressed the effect of isoenergetic fructose replacement of glucose or sucrose on peak postprandial glucose, insulin, and triglyceride concentrations. Objective: The objective of this study was to review the evidence for postprandial glycemic and insulinemic responses after isoenergetic replacement of either glucose or sucrose in foods or beverages with fructose. Design: We searched the Cochrane Library, MEDLINE, EMBASE, the WHO International Clinical Trials Registry Platform Search Portal, and clinicaltrials.gov The date of the last search was 26 April 2016. We included randomized controlled trials measuring peak postprandial glycemia after isoenergetic replacement of glucose, sucrose, or both with fructose in healthy adults or children with or without diabetes. The main outcomes analyzed were peak postprandial blood glucose, insulin, and triglyceride concentrations. Results: Replacement of either glucose or sucrose by fructose resulted in significantly lowered peak postprandial blood glucose, particularly in people with prediabetes and type 1 and type 2 diabetes. Similar results were obtained for insulin. Peak postprandial blood triglyceride concentrations did not significantly increase. Conclusions: Strong evidence exists that substituting fructose for glucose or sucrose in food or beverages lowers peak postprandial blood glucose and insulin concentrations. Isoenergetic replacement does not result in a substantial increase in blood triglyceride concentrations. © 2017 American Society for Nutrition.

Newborn screening blood spot analysis in the UK: influence of spot size, punch location and haematocrit.

PubMed

Lawson, A J; Bernstone, L; Hall, S K

2016-03-01

In dried blood spot analysis, punch location and variations in applied sample volume and haematocrit can produce different measured concentrations of analytes. We investigated the magnitude of these effects in newborn screening in the UK. Heparinized blood spiked with thyroid stimulating hormone (TSH), phenylalanine, tyrosine, leucine, methionine, octanoyl carnitine (C8), and immunoreactive trypsinogen (IRT) was spotted onto filter paper: (i) at a constant haematocrit of 50% at various volumes, and (ii) at a range of haematocrits using a constant volume. Subpunches (3.2 mm) of the dried blood spots were then analysed. Compared with a central punch from a 50 µL blood spot with 50% haematocrit, 10 µL spots can have significantly lower measured concentrations of all analytes, with decreases of 15% or more observed for leucine, methionine, phenylalanine, and tyrosine. Punching at the edge of a spot can increase measured concentrations up to 35%. Higher haematocrit decreased measured TSH and C8 yet increased amino acids and IRT by 15% compared with 50% haematocrit. Lower haematocrits had the opposite effect, but only with higher concentrations of some analytes. Differences in blood spot size, haematocrit and punch location substantially affect measured concentrations for analytes used in the UK newborn screening programme, and this could affect false positive and negative rates. To minimize analytical bias, these variables should be controlled or adjusted for where possible. © The Author(s) 2015.

Endogenous Thrombin Potential Changes during the First Cycle of Oral Contraceptive Use

PubMed Central

Westhoff, Carolyn L.; Pike, Malcolm C.; Cremers, Serge; Eisenberger, Andrew; Thomassen, Stella; Rosing, Jan

2017-01-01

Objectives Venous thromboembolism (VTE) risk increases within months of combination oral contraceptive (COC) initiation. Because elevated endogenous thrombin potential (ETP) has been found in several studies to be a VTE risk factor, we evaluated the extent of ETP changes during the initial cycle of an ethinyl estradiol (EE) and levonorgestrel (LNG) COC. We also assessed the relationship between ETP changes and systemic EE and LNG concentrations. Study Design Participants provided multiple blood samples during a first 21-day cycle of a 30 µg EE/150 µg LNG COC and after a further 7 days without an active COC. Thrombin generation measured with and without addition of activated protein C (APC) yielded ETP+APC and ETP−APC and the normalized APC sensitivity ratio (nAPCsr). EE and LNG pharmacokinetic analyses were conducted over 24 hours after the first COC tablet and again at steady state. Results Thrombin generation was determined in 16 of the 17 women who completed the study. Mean ETP−APC increased steadily to 21% above baseline at 24 hours after the 6th COC tablet (COC624; p < 0.001) and to 28% above baseline at steady state (COC21; p < 0.001). Mean ETP+APC increased considerably more – by 54% at COC624 and by 79% at steady state. Mean nAPCsr increased by 28% at COC624 and by 41% at steady state. Higher concentrations of EE or LNG were not correlated with greater increases in ETP. Conclusions ETP increases during the first COC cycle were substantial. Implications The early increases in ETP may provide biological support for the rapid increase in VTE risk during initial COC use. The lack of association between this clotting system perturbation and the systemic EE concentration is surprising and deserves further study. PMID:28088496

Plasma 8-iso-Prostaglandin F2α concentrations and outcomes after acute intracerebral hemorrhage.

PubMed

Du, Quan; Yu, Wen-Hua; Dong, Xiao-Qiao; Yang, Ding-Bo; Shen, Yong-Feng; Wang, Hao; Jiang, Li; Du, Yuan-Feng; Zhang, Zu-Yong; Zhu, Qiang; Che, Zhi-Hao; Liu, Qun-Jie

2014-11-01

Higher plasma 8-iso-Prostaglandin F2α concentrations have been associated with poor outcome of severe traumatic brain injury. We further investigated the relationships between plasma 8-iso-Prostaglandin F2α concentrations and clinical outcomes in patients with acute intracerebral hemorrhage. Plasma 8-iso-Prostaglandin F2α concentrations of 128 consecutive patients and 128 sex- and gender-matched healthy subjects were measured by enzyme-linked immunosorbent assay. We assessed their relationships with disease severity and clinical outcomes including 1-week mortality, 6-month mortality and unfavorable outcome (modified Rankin Scale score>2). Plasma 8-iso-Prostaglandin F2α concentrations were substantially higher in patients than in healthy controls. Plasma 8-iso-Prostaglandin F2α concentrations were positively associated with National Institutes of Health Stroke Scale (NIHSS) scores and hematoma volume using a multivariate linear regression. It emerged as an independent predictor for clinical outcomes of patients using a forward stepwise logistic regression. ROC curves identified the predictive values of plasma 8-iso-Prostaglandin F2α concentrations, and found its predictive value was similar to NIHSS scores and hematoma volumes. However, it just numerically added the predictive values of NIHSS score and hematoma volume. Increased plasma 8-iso-Prostaglandin F2α concentrations are associated with disease severity and clinical outcome after acute intracerebral hemorrhage. Copyright © 2014 Elsevier B.V. All rights reserved.

Pollutant Concentrations and Emission Rates from Scripted Natural Gas Cooking Burner Use in Nine Northern California Homes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singer, Brett C.; Delp, William W.; Lorenzetti, David M.

METHODS: Combustion pollutant concentrations were measured during the scripted operation of natural gas cooking burners in nine homes. In addition to a base condition of closed windows, no forced air unit (FAU) use, and no mechanical exhaust, additional experiments were conducted while operating an FAU and/or vented range hood. Test homes included a 26m2 two-room apartment, a 134m2 first floor flat, and seven detached homes of 117–226m2. There were four single-story, four two-story and one 1.5 story homes. Cooktop use entailed boiling and simmering activities, using water as a heat sink. Oven and broiler use also were simulated. Time-resolved concentrationsmore » of carbon dioxide (CO2), nitric oxide (NO), nitrogen oxides (NOX), nitrogen dioxide (NO2), particles with diameters of 6 nm or larger (PN), carbon monoxide (CO), and fine particulate matter (PM2.5) were measured in the kitchen (K) and bedroom area (BR) of each home. CO2, NO, NO2, and PN data from sequential experiments were analyzed to quantify the contribution of burner use to the highest 1h and 4h time-integrated concentrations in each room. RESULTS: Four of the nine homes had kitchen 1h NO2 exceed the national ambient air quality standard (100 ppb). Two other homes had 1h NO2 exceed 50 ppb in the kitchen, and three had 1h NO2 above 50 ppb in the bedroom, suggesting substantial exposures to anyone at home when burners are used for a single substantial event. In all homes, the highest 1h kitchen PN exceeded 2 x105 cm-3-h, and the highest 4h PN exceeded 3 x105 cm-3-hr in all homes. The lowest 1h kitchen/bedroom ratios were 1.3–2.1 for NO in the apartment and two open floor plan homes. The largest K/BR ratios of 1h NO2 were in a two-story 1990s home retrofitted for deep energy savings: ratios in this home were 3.3 to 6.6. Kitchen 1h ratios of NO, NO2 and PN to CO2 were used to calculate fuel normalized emission factors (ng J-1). Range hood use substantially reduced cooking burner pollutant concentrations both in the kitchen and bedroom of several homes. A hood with large capture volume and a measured flow of 108 L/s reduced concentrations 80-95%. IMPLICATIONS: These measurements demonstrate that operation of natural gas cooking burners without venting can cause short-term kitchen concentrations of NO2 to exceed the US outdoor health standard, and can elevate concentrations of NO, NO2, and ultrafine particles throughout the home. Results are generally consistent with a recent simulation study that estimated widespread 1h NO2 exposures exceeding 100 ppb in homes that use gas burners without venting. While operating a venting range hood can greatly reduce pollutant levels from burner use (and presumably from cooking as well), performance varies widely across hoods. Increased awareness of the need to ventilate when cooking would substantially reduce in-home exposure to NO2 and ultrafine particles in California homes. Helping consumers select effective hoods, for example by publishing capture efficiency performance ratings, also would help reduce exposure.« less

Water quality effects of herded stream crossings by domestic sheep bands.

PubMed

Clark, Patrick E; Moffet, Corey A; Lewis, Gregory S; Seyfried, Mark S; Hardegree, Stuart P; Pierson, Fredrick B

2012-01-01

Livestock impacts on total suspended solids (TSS) and pathogen (e.g., ) levels in rangeland streams are a serious concern worldwide. Herded stream crossings by domestic sheep () are periodic, necessary managerial events on high-elevation rangelands, but their impacts on stream water quality are largely unknown. We evaluated the effects of herded, one-way crossings by sheep bands (about 2000 individuals) on TSS and concentration and load responses in downstream waters. Crossing trials were conducted during the summers of 2005 and 2006 on two reaches within each of three perennial streams in the Centennial Mountains of eastern Idaho and southwestern Montana. Water samples were collected at 2-min intervals at an upstream background station and at stations 25, 100, 500, and 1500 m downstream just before and during each crossing trial. Crossings produced substantial increases in TSS and concentrations and loads downstream, but these concentration increases were localized and short lived. Maximum TSS concentration was highest 25 m downstream, declined as a function of downstream distance, and at 500 m downstream was similar to background. Post-peak TSS concentrations at all downstream stations decreased to <25 mg L within 24 to 48 min after reaching their maxima. Findings for concentration and load responses were similar to that of TSS but less clear cut. Stream-crossing sheep do affect water quality; therefore, producers and resource managers should continue to evaluate the efficacy of herdsmanship techniques for reducing water quality impact. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Changes in springtime tropospheric ozone at Mt. Happo from 1998 to 2016, linked to Asian emissions and North Pacific climate

NASA Astrophysics Data System (ADS)

Okamoto, S.; Tanimoto, H.; Hirota, N.; Ikeda, K.; Akimoto, H.

2017-12-01

During the past decades, springtime ozone concentrations in the downwind regions of East Asia have rapidly increased with the increase of anthropogenic emissions. However, recent several studies based on the analysis of satellite tropospheric nitrogen dioxides data inferred possible peaking out of nitrogen oxides emissions in China. In addition to the precursor emissions, climate plays an important role in controlling the variations and distributions of tropospheric ozone. Here we revisited and updated the long-term trend of tropospheric ozone at Mt. Happo, Japan, for the period from 1998 to 2016. Since 1998 the springtime ozone concentration has shown a large increase until 2007, very likely caused by the increase in the emissions of ozone precursors associated with economic growth in eastern China, as evidenced from satellite observations of nitrogen dioxides. After the monotonic increase until 2007, the ozone level has been flattened associated with substantial drop in 2008. Recent low ozone levels were largely influenced by the decrease of the anthropogenic emissions from eastern China. We also found that the efficiency of long-range transport from central eastern China, driven by North Pacific climate, play a role in modulating the year-to-year variations of ozone at Mt. Happo.

Effects of weather on the retrieval of sea ice concentration and ice type from passive microwave data

NASA Technical Reports Server (NTRS)

Maslanik, J. A.

1992-01-01

Effects of wind, water vapor, and cloud liquid water on ice concentration and ice type calculated from passive microwave data are assessed through radiative transfer calculations and observations. These weather effects can cause overestimates in ice concentration and more substantial underestimates in multi-year ice percentage by decreasing polarization and by decreasing the gradient between frequencies. The effect of surface temperature and air temperature on the magnitudes of weather-related errors is small for ice concentration and substantial for multiyear ice percentage. The existing weather filter in the NASA Team Algorithm addresses only weather effects over open ocean; the additional use of local open-ocean tie points and an alternative weather correction for the marginal ice zone can further reduce errors due to weather. Ice concentrations calculated using 37 versus 18 GHz data show little difference in total ice covered area, but greater differences in intermediate concentration classes. Given the magnitude of weather-related errors in ice classification from passive microwave data, corrections for weather effects may be necessary to detect small trends in ice covered area and ice type for climate studies.

Topotecan lacks third space sequestration.

PubMed

Gelderblom, H; Loos, W J; Verweij, J; de Jonge, M J; Sparreboom, A

2000-04-01

The objective of this study was to determine the influence of pleural and ascitic fluid on the pharmacokinetics of the antitumor camptothecin derivative topotecan. Four patients with histological proof of malignant solid tumor received topotecan (0.45 or 1.5 mg/m2) p.o. on several occasions in both the presence and absence of third space volumes. Serial plasma and pleural or ascitic fluid samples were collected during each dosing and analyzed by high-performance liquid chromatography for both the intact lactone form of topotecan and its ring-opened carboxylate form. The apparent topotecan clearance demonstrated substantial interpatient variability but remained unchanged within the same patient in the presence [110 +/- 55.6 liters/ h/m2 (mean +/- SD of eight courses)] or absence of pleural and ascitic fluid [118 +/- 31.1 liters/h/m2 (mean +/- SD of seven courses)]. Similarly, terminal half-lives and area under the concentration-time curve ratios of lactone:total drug in plasma were similar between courses within each patient. Topotecan penetration into pleural and ascitic fluid demonstrated a mean lag time of 1.61 h (range, 1.37-1.86 h), and ratios with plasma concentration increased with time after dosing in all patients. The mean ratio of third space topotecan total drug area under the concentration-time curve to that in plasma was 0.55 (range, 0.26-0.87). These data indicate that topotecan can be safely administered to patients with pleural effusions or ascites and that there is substantial penetration of topotecan into these third spaces, which may prove beneficial for local antitumor effects.

Hydrologic Effects of the 1988 Galena Fire, Black Hills Area, South Dakota

USGS Publications Warehouse

Driscoll, Daniel G.; Carter, Janet M.; Ohlen, Donald O.

2004-01-01

The Galena Fire burned about 16,788 acres of primarily ponderosa pine forest during July 5-8, 1988, in the Black Hills area of South Dakota. The fire burned primarily within the Grace Coolidge Creek drainage basin and almost entirely within the boundaries of Custer State Park. A U.S. Geological Survey gaging station with streamflow records dating back to 1977 was located along Grace Coolidge Creek within the burned area. About one-half of the gaging station's 26.8-square-mile drainage area was burned. The drainage basin for Bear Gulch, which is tributary to Grace Coolidge Creek, was burned particularly severely, with complete deforestation occurring in nearly the entirety of the area upstream from a gaging station that was installed in 1989. A study to evaluate effects of the Galena Fire on streamflow, geomorphology, and water quality was initiated in 1988. The geomorphologic and water-quality components of the study were completed by 1990 and are summarized in this report. A data-collection network consisting of streamflow- and precipitation-gaging stations was operated through water year 1998 for evaluation of effects on streamflow characteristics, including both annual-yield and peak-flow characteristics, which are the main focus of this report. Moderately burned areas did not experience a substantial increase in the rate of surface erosion; however, severely burned areas underwent surficial erosion nearly twice that of the unburned areas. The sediment production rate of Bear Gulch estimated 8 to 14 months after the fire was 870 ft3/acre (44 tons/acre). Substantial degradation of stream channels within the severely burned headwater areas of Bear Gulch was documented. Farther downstream, channel aggradation resulted from deposition of sediments transported from the headwater areas. The most notable water-quality effect was on concentrations of suspended sediment, which were orders of magnitude higher for Bear Gulch than for the unburned control area. Effects on several other water-quality constituents, such as organic carbon and nitrogen and phosphorus nutrient constituents, probably were influenced by the large concentrations of suspended matter that were documented in initial post-fire, storm-flow events. The first post-fire stormflow produced the highest measured concentrations of specific conductance, nitrogen, phosphorus, organic carbon, calcium, magnesium, potassium, manganese, and sulfate in the burned areas. For most constituents sampled, differences in concentrations between burned and unburned areas were no longer discernible within about 1 year following the Galena Fire. The effects of the Galena Fire on annual-yield characteristics of Grace Coolidge Creek were evaluated primarily from comparisons with long-term streamflow records for Battle Creek, which is hydrogeologically similar and is located immediately to the north. Annual yield for Grace Coolidge Creek increased by about 20 percent as a result of the fire. This estimate was based on relations between annual yield for Grace Coolidge Creek and Battle Creek for pre- and post-burn periods. Many of the post-burn data points are well beyond the range of the pre-burn data, which is a source of uncertainty for this estimate. Substantial increases in peak-flow characteristics for severely burned drainages were visually apparent from numerous post-fire field observations. Various analyses of streamflow data indicated substantial increases in peak-flow response for burned drainage areas; however, quantification of effects was particularly difficult because peak-flow response diminished quickly and returned to a generally pre-burn condition by about 1991. Field observations of vegetation and analysis of remotely sensed data indicated that establishment of grasses and forbs occurred within a similar timeframe. Comparison of pre-fire peak flows to post-1991 peak flows indicates that these grasses and forbs were equally effective in suppressing peak flows

DISTRIBUTION OF ORGANIC WASTEWATER CONTAMINANTS BETWEEN WATER AND SEDIMENT IN SURFACE WATERS OF THE UNITED STATES

EPA Science Inventory

Trace concentrations of pharmaceuticals and other organic wastewater contaminants have been determined in the surface waters of Europe and the United States. A preliminary report of substantially higher concentrations of pharmaceuticals in sediment suggests that bottom sediment ...

Uncertainty in monitoring E. coli concentrations in streams and stormwater runoff

USDA-ARS?s Scientific Manuscript database

Microbial contamination in surface waters is a substantial public health concern throughout the world. Contamination is typically identified by, and restoration plans predicated upon, fecal indicator bacteria such as E. coli. Thus, monitoring of E. coli concentrations is critical to evaluate curre...

Modeling Geographic and Demographic Variability in Residential Concentrations of Environmental Tobacco Smoke Using National Data Sets

EPA Science Inventory

Despite substantial attention toward environmental tobacco smoke (ETS) exposure, previous studies have not provided adequate information to apply broadly within community-scale risk assessments. We aim to estimate residential concentrations of particulate matter (PM) from ETS in ...

Association between PM10 concentrations and school absences in proximity of a cement plant in northern Italy.

PubMed

Marcon, Alessandro; Pesce, Giancarlo; Girardi, Paolo; Marchetti, Pierpaolo; Blengio, Gianstefano; de Zolt Sappadina, Simona; Falcone, Salvatore; Frapporti, Guglielmo; Predicatori, Francesca; de Marco, Roberto

2014-03-01

Dusts are one of the main air pollutants emitted during cement manufacturing. A substantial part of these are breathable particles that are less than 10 μm in diameter (PM10), which represent a potential threat for the health of the exposed population. This study aimed at evaluating the short-term effects of PM10 concentrations on the health of children, aged 6-14 years, who attended the schools in Fumane (Italy), in proximity (1.2 km) to a large cement plant. School absenteeism was used as a proxy indicator of child morbidity. Time series of daily school absences and PM10 concentrations were collected for 3 school-years from 2007 to 2010 (541 school-days, 462 children on average). The associations between PM10 concentrations and school absence rates in the same day (lag0) and in the following 4 days (lag1 to lag4) were evaluated using generalised additive models, smoothed for medium/long term trends and adjusted for day of the week, influenza outbreaks, daily temperature and rain precipitations. The average concentration of PM10 in the period was 34 (range: 4-183) μg/m(3). An average 10 μg/m(3) increase of PM10 concentration in the previous days (lag0-4) was associated with a statistically significant 2.5% (95%CI: 1.1-4.0%) increase in the rate of school absences. The highest increase in the absence rates (2.4%; 95%CI: 1.2-3.5%) was found 2 days after exposure (lag2). These findings provide epidemiological evidence of the acute health effects of PM10 in areas with annual concentrations that are lower than the legal European Union limit of 40 μg/m(3), and support the need to establish more restrictive legislative standards. Copyright © 2013 Elsevier GmbH. All rights reserved.

Decadal-scale changes in dissolved-solids concentrations in groundwater used for public supply, Salt Lake Valley, Utah

USGS Publications Warehouse

Thiros, Susan A.; Spangler, Larry

2010-01-01

Basin-fill aquifers are a major source of good-quality water for public supply in many areas of the southwestern United States and have undergone increasing development as populations have grown over time. During 2005, the basin-fill aquifer in Salt Lake Valley, Utah, provided approximately 75,000 acre-feet, or about 29 percent of the total amount of water used by a population of 967,000. Groundwater in the unconsolidated basin-fill deposits that make up the aquifer occurs under unconfined and confined conditions. Water in the shallow unconfined part of the groundwater system is susceptible to near-surface contamination and generally is not used as a source of drinking water. Groundwater for public supply is withdrawn from the deeper unconfined and confined parts of the system, termed the principal aquifer, because yields generally are greater and water quality is better (including lower dissolved-solids concentrations) than in the shallower parts of the system. Much of the water in the principal aquifer is derived from recharge in the adjacent Wasatch Range (mountain-block recharge). In many areas, the principal aquifer is separated from the overlying shallow aquifer by confining layers of less permeable, fine-grained sediment that inhibit the downward movement of water and any potential contaminants from the surface. Nonetheless, under certain hydrologic conditions, human-related activities can increase dissolved-solids concentrations in the principal aquifer and result in groundwater becoming unsuitable for consumption without treatment or mixing with water having lower dissolved-solids concentrations. Dissolved-solids concentrations in areas of the principal aquifer used for public supply typically are less than 500 milligrams per liter (mg/L), the U.S. Environmental Protection Agency (EPA) secondary (nonenforceable) drinking-water standard. However, substantial increases in dissolved-solids concentrations in the principal aquifer have been documented in some areas used for public supply, raising concerns as to the source(s) and cause(s) of the higher concentrations and the potential long-term effects on groundwater quality.

Intra- and inter-basin mercury comparisons: Importance of basin scale and time-weighted methylmercury estimates

USGS Publications Warehouse

Bradley, Paul M.; Journey, Celeste A.; Bringham, Mark E.; Burns, Douglas A.; Button, Daniel T.; Riva-Murray, Karen

2013-01-01

To assess inter-comparability of fluvial mercury (Hg) observations at substantially different scales, Hg concentrations, yields, and bivariate-relations were evaluated at nested-basin locations in the Edisto River, South Carolina and Hudson River, New York. Differences between scales were observed for filtered methylmercury (FMeHg) in the Edisto (attributed to wetland coverage differences) but not in the Hudson. Total mercury (THg) concentrations and bivariate-relationships did not vary substantially with scale in either basin. Combining results of this and a previously published multi-basin study, fish Hg correlated strongly with sampled water FMeHg concentration (p = 0.78; p = 0.003) and annual FMeHg basin yield (p = 0.66; p = 0.026). Improved correlation (p = 0.88; p < 0.0001) was achieved with time-weighted mean annual FMeHg concentrations estimated from basin-specific LOADEST models and daily streamflow. Results suggest reasonable scalability and inter-comparability for different basin sizes if wetland area or related MeHg-source-area metrics are considered.

Comparison of four different cardiac troponin assays in patients with end-stage renal disease on chronic haemodialysis.

PubMed

Helleskov Madsen, Lene; Ladefoged, Søren; Hildebrandt, Per; Atar, Dan

2008-01-01

Several studies have documented the importance of troponin elevation as a prognostic marker in end-stage renal disease (ESRD). The reason for the elevated concentrations is not clarified. We do not know whether the different assays recognize the same patients within ESRD populations. The aim of this study was to compare concentrations of troponin measured by four different assays in a cohort of patients with ESRD, to investigate whether haemodialysis affects troponin concentrations, and to compare the prognostic potential of the different assays. We included 109 patients on chronic haemodialysis. Serum cardiac troponin T (cTnT) was measured pre- and postdialysis using Elecsys 2010 and troponin I (cTnI) using Access AccuTnI, Dimension RxL and AIA-600II. The cTnT assay had the highest percentage of elevated concentrations for all chosen cut-offs with a reduction in percentage of patients with elevated concentrations during haemodialysis. Elecsys 2010 and AIA-600II demonstrated a significant increased mortality with raised concentrations of troponin. The diverging results in previous studies are most likely based on substantial differences in the analytical performance of the assays. The prognostic value of cTnT appears superior to cTnI, which amplifies the prognostic significance of this cardiovascular marker in patients with ESRD.

Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals

PubMed Central

Peterson, Sarah H.; Ackerman, Joshua T.; Costa, Daniel P.

2015-01-01

Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200–1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and δ13C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation. PMID:26085591

Calculations of critical micelle concentration by dissipative particle dynamics simulations: the role of chain rigidity.

PubMed

Lee, Ming-Tsung; Vishnyakov, Aleksey; Neimark, Alexander V

2013-09-05

Micelle formation in surfactant solutions is a self-assembly process governed by complex interplay of solvent-mediated interactions between hydrophilic and hydrophobic groups, which are commonly called heads and tails. However, the head-tail repulsion is not the only factor affecting the micelle formation. For the first time, we present a systematic study of the effect of chain rigidity on critical micelle concentration and micelle size, which is performed with the dissipative particle dynamics simulation method. Rigidity of the coarse-grained surfactant molecule was controlled by the harmonic bonds set between the second-neighbor beads. Compared to flexible molecules with the nearest-neighbor bonds being the only type of bonded interactions, rigid molecules exhibited a lower critical micelle concentration and formed larger and better-defined micelles. By varying the strength of head-tail repulsion and the chain rigidity, we constructed two-dimensional diagrams presenting how the critical micelle concentration and aggregation number depend on these parameters. We found that the solutions of flexible and rigid molecules that exhibited approximately the same critical micelle concentration could differ substantially in the micelle size and shape depending on the chain rigidity. With the increase of surfactant concentration, primary micelles of more rigid molecules were found less keen to agglomeration and formation of nonspherical aggregates characteristic of flexible molecules.

Rapid changes in small fish mercury concentrations in estuarine wetlands: Implications for wildlife risk and monitoring programs

USGS Publications Warehouse

Eagles-Smith, Collin A.; Ackerman, Joshua T.

2009-01-01

Small fish are commonly used to assess mercury (Hg) risk to wildlife and monitor Hg in wetlands. However, limited research has evaluated short-term Hg variability in small fish, which can have important implications for monitoring programs and risk assessment. We conducted a time-series study of Hg concentrations in two small fish species representing benthic (longjaw mudsuckers [Gillichthys mirabilis]) and pelagic (threespine sticklebacks [Gasterosteus aculeatus]) food-webs within three wetland habitats in San Francisco Bay Estuary. We simultaneously monitored prey deliveries, nest initiation, and chick hatching dates of breeding Forster's terns (Sterna forsteri), the most abundant nesting piscivore in the region. Mudsuckers and sticklebacks were the predominant prey fish, comprising 36% and 25% of tern diet, and Hg concentrations averaged (geometric mean ?? SE, ??g/g dw) 0.44 ?? 0.01 and 0.68 ?? 0.03, respectively. Fish Hg concentrations varied substantially over time following a quadratic form in both species, increasing 40% between March and May then decreasing 40% between May and July. Importantly, Forster's terns initiated 68% of nests and 31% of chicks hatched during the period of peak Hg concentrations in prey fish. These results illustrate the importance of short-term temporal variation in small fish Hg concentrations for both Hg monitoring programs and assessing wildlife risk.

A comparative study of optical concentrators for visible light communications

NASA Astrophysics Data System (ADS)

Mulyawan, Rahmat; Gomez, Ariel; Chun, Hyunchae; Rajbhandari, Sujan; Manousiadis, Pavlos P.; Vithanage, Dimali A.; Faulkner, Grahame; Turnbull, Graham A.; Samuel, Ifor D. W.; Collins, Stephen; O'Brien, Dominic

2017-01-01

Given the imminent radio frequency spectrum crunch, Visible Light Communication (VLC) is being proposed as an alternative wireless technology allowing for scalable connectivity to potentially millions of mobile and Internet-of- Things (IoT) devices. A VLC system uses a photo-detector (PD) receiver that converts the optically modulated light from a light source into a modulated electrical signal. The corresponding receiver electrical bandwidth is typically inversely proportional to the PD active area. Consequently, to construct a high-speed VLC link, the PD active area is often substantially reduced and an optical concentrator is used to enhance the receiver collection area. However, to achieve high concentrating factor, the link field-of-view (FOV) needs to be narrow due to the étendue conservation in linear passive optical systems. This paper studies a Fluorescent Concentrator (FC) that breaks this étendue conservation. The FC is not only based on reflective and refractive principles but also makes use of fluorescence process. A comparison between the FC and conventional optical concentrators, namely Compound Parabolic Concentrator (CPC) is also investigated. The trade-off between received signal strength and incoming link angle is demonstrated over 60° coverage. Experimental results show that performance degradation as the link angle increases using FC-based receivers is significantly lower than for conventional CPC.

Sensitivity of Ocean Chemistry and Oxygen Change to the Uncertainty in Climate Change

NASA Astrophysics Data System (ADS)

Cao, L.; Wang, S.; Zheng, M.; Zhang, H.

2014-12-01

With increasing atmospheric CO2 and climate change, global ocean is undergoing substantial physical and biogeochemical changes. In particular, changes in ocean oxygen and carbonate chemistry have great implication for marine biota. There is considerable uncertainty in the projections of future climate change, and it is unclear how the uncertainty in climate change would affect the projection of ocean oxygen and carbonate chemistry. To examine the effect of climate change on ocean oxygen and carbonate chemistry, we used an Earth system model of intermediate complexity to perform simulations that are driven by atmospheric CO2 concentration pathway of RCP 8.5 with climate sensitivity varying from 0.0°C to 4.5 °C. Climate change affects carbonate chemistry and oxygen mainly through its impact on ocean temperature, ocean ventilation, and concentration of dissolved inorganic carbon and alkalinity. Our simulations show that climate change mitigates the decrease of carbonate ions at the ocean surface but has negligible effect on surface ocean pH. Averaged over the whole ocean, climate change acts to decrease oxygen concentration but mitigates the CO2-induced reduction of carbonate ion and pH. In our simulations, by year 2500, every degree increase of climate sensitivity warms the ocean by 0.8 °C and reduces ocean-mean dissolved oxygen concentration by 5.0%. Meanwhile, every degree increase of climate sensitivity buffers CO2-induced reduction in ocean-mean carbonate ion concentration and pH by 3.4% and 0.02 units, respectively. Our study demonstrates different sensitivities of ocean temperature, carbonate chemistry, and oxygen, in terms of both the sign and magnitude, to the amount of climate change, which have great implications for understanding the response of ocean biota to climate change.

Contribution of rivaroxaban to the international normalized ratio when switching to warfarin for anticoagulation as determined by simulation studies

PubMed Central

Siegmund, Hans-Ulrich; Burghaus, Rolf; Kubitza, Dagmar; Coboeken, Katrin

2015-01-01

Aim This study evaluated the influence of rivaroxaban 20 mg once daily on international normalized ratio (INR) during the co-administration period when switching from rivaroxaban to warfarin. Methods We developed a calibrated coagulation model that was qualified with phase I clinical data. Prothrombin time and INR values were simulated by use of phospholipid concentrations that matched Neoplastin Plus® and Innovin® reagents. To simulate the combined effects of rivaroxaban and warfarin on INR during switching, warfarin initiation was simulated by adjusting the magnitude of the warfarin effect to reach the desired target INRs over the course of 21 days. The warfarin effect values (obtained every 6 h) and the desired rivaroxaban plasma concentrations were used. Nomograms were generated from rivaroxaban induced increases in INR. Results The simulation had good prediction quality. Rivaroxaban induced increases in the total INR from the warfarin attributed INR were seen, which increased with rivaroxaban plasma concentration. When the warfarin only INR was 2.0–3.0, the INR contribution of rivaroxaban with Neoplastin Plus® was 0.5–1.2, decreasing to 0.3–0.6 with Innovin® at median trough rivaroxaban plasma concentrations (38 μg l−1). Conclusions The data indicate that measuring warfarin induced changes in INR are best performed at trough rivaroxaban concentrations (24 h after rivaroxaban dosing) during the co-administration period when switching from rivaroxaban to warfarin. Furthermore, Innovin® is preferable to Neoplastin Plus® because of its substantially lower sensitivity to rivaroxaban, thereby reducing the influence of rivaroxaban on the measured INR. PMID:25510952

Specific biomarkers for stochastic division patterns and starvation-induced quiescence under limited glucose levels in fission yeast

PubMed Central

Pluskal, Tomáš; Hayashi, Takeshi; Saitoh, Shigeaki; Fujisawa, Asuka; Yanagida, Mitsuhiro

2011-01-01

Glucose as a source of energy is centrally important to our understanding of life. We investigated the cell division–quiescence behavior of the fission yeast Schizosaccharomyces pombe under a wide range of glucose concentrations (0–111 mm). The mode of S. pombe cell division under a microfluidic perfusion system was surprisingly normal under highly diluted glucose concentrations (5.6 mm, 1/20 of the standard medium, within human blood sugar levels). Division became stochastic, accompanied by a curious division-timing inheritance, in 2.2–4.4 mm glucose. A critical transition from division to quiescence occurred within a narrow range of concentrations (2.2–1.7 mm). Under starvation (1.1 mm) conditions, cells were mostly quiescent and only a small population of cells divided. Under fasting (0 mm) conditions, division was immediately arrested with a short chronological lifespan (16 h). When cells were first glucose starved prior to fasting, they possessed a substantially extended lifespan (∼14 days). We employed a quantitative metabolomic approach for S. pombe cell extracts, and identified specific metabolites (e.g. biotin, trehalose, ergothioneine, S-adenosyl methionine and CDP-choline), which increased or decreased at different glucose concentrations, whereas nucleotide triphosphates, such as ATP, maintained high concentrations even under starvation. Under starvation, the level of S-adenosyl methionine increased sharply, accompanied by an increase in methylated amino acids and nucleotides. Under fasting, cells rapidly lost antioxidant and energy compounds, such as glutathione and ATP, but, in fasting cells after starvation, these and other metabolites ensuring longevity remained abundant. Glucose-starved cells became resistant to 40 mm H2O2 as a result of the accumulation of antioxidant compounds. PMID:21306563

Interpretation of urinary concentrations of pseudoephedrine and its metabolite cathine in relation to doping control.

PubMed

Deventer, K; Van Eenoo, P; Baele, G; Pozo, O J; Van Thuyne, W; Delbeke, F T

2009-05-01

Until the end of 2003 a urinary concentration of pseudoephedrine exceeding 25 microg/mL was regarded as a doping violation by the World Anti-Doping Agency. Since its removal from the prohibited list in 2004 the number of urine samples in which pseudoephedrine was detected in our laboratory increased substantially. Analysis of 116 in-competition samples containing pseudoephedrine in 2007 and 2008, revealed that 66% of these samples had a concentration of pseudoephedrine above 25 microg/mL. This corresponded to 1.4% of all tested in competition samples in that period. In the period 2001-2003 only 0.18% of all analysed in competition samples contained more than 25 microg/mL. Statistical comparison of the two periods showed that after the removal of pseudoephedrine from the list its use increased significantly. Of the individual sports compared between the two periods, only cycling is shown to yield a significant increase.Analysis of excretion urine samples after administration of a therapeutic daily dose (240 mg pseudoephedrine) in one administration showed that the threshold of 25 microg/mL can be exceeded. The same samples were also analysed for cathine, which has currently a threshold of 5 microg/mL on the prohibited list. The maximum urinary concentration of cathine also exceeded the threshold for some volunteers. Comparison of the measured cathine and pseudoephedrine concentrations only indicated a poor correlation between them. Hence, cathine is not a good indicator to control pseudopehedrine intake. To control the (ab)use of ephedrines in sports it is recommended that WADA reintroduce a threshold for pseudoephedrine. Copyright 2009 John Wiley & Sons, Ltd.

Advantages of Pure Platelet-Rich Plasma Compared with Leukocyte- and Platelet-Rich Plasma in Treating Rabbit Knee Osteoarthritis

PubMed Central

Yin, Wen-Jing; Xu, Hai-Tao; Sheng, Jia-Gen; An, Zhi-Quan; Guo, Shang-Chun; Xie, Xue-Tao; Zhang, Chang-Qing

2016-01-01

Background Concentrated leukocytes in leukocyte- and platelet-rich plasma (L-PRP) may deliver increased levels of pro-inflammatory cytokines to activate the NF-κB signaling pathway, to counter the beneficial effects of growth factors on osteoarthritic cartilage. However, to date no relevant studies have substantiated that in vivo. Material/Methods Autologous L-PRP and pure platelet-rich plasma (P-PRP) were prepared, measured for componential composition, and injected intra-articularly after 4, 5, and 6 weeks post-anterior cruciate ligament transection. Caffeic acid phenethyl ester (CAPE) was injected intraperitoneally to inhibit NF-κB activation. All rabbits were sacrificed after 8 weeks postoperative. Enzyme-linked immunosorbent assays were performed to determine interleukin 1β (IL-1β) and prostaglandin E2 (PGE2) concentrations in the synovial fluid, Indian ink staining was performed for gross morphological assessment, and hematoxylin and eosin staining and toluidine blue staining were performed for histological assessment. Results Compared with L-PRP, P-PRP injections achieved better outcomes regarding the prevention of cartilage destruction, preservation of cartilaginous matrix, and reduction of IL-1β and PGE2 concentrations. CAPE injections reversed the increased IL-1β and PGE2 concentrations in the synovial fluid after L-PRP injections and improved the outcome of L-PRP injections to a level similar to P-PRP injections, while they had no influence on the therapeutic efficacy of P-PRP injections. Conclusions Concentrated leukocytes in L-PRP may release increased levels of pro-inflammatory cytokines to activate the NF-κB signaling pathway, to counter the beneficial effects of growth factors on osteoarthritic cartilage, and finally, result in a inferior efficacy of L-PRP to P-PRP for the treatment of osteoarthritis. PMID:27086145

Advantages of Pure Platelet-Rich Plasma Compared with Leukocyte- and Platelet-Rich Plasma in Treating Rabbit Knee Osteoarthritis.

PubMed

Yin, Wen-Jing; Xu, Hai-Tao; Sheng, Jia-Gen; An, Zhi-Quan; Guo, Shang-Chun; Xie, Xue-Tao; Zhang, Chang-Qing

2016-04-17

BACKGROUND Concentrated leukocytes in leukocyte- and platelet-rich plasma (L-PRP) may deliver increased levels of pro-inflammatory cytokines to activate the NF-κB signaling pathway, to counter the beneficial effects of growth factors on osteoarthritic cartilage. However, to date no relevant studies have substantiated that in vivo. MATERIAL AND METHODS Autologous L-PRP and pure platelet-rich plasma (P-PRP) were prepared, measured for componential composition, and injected intra-articularly after 4, 5, and 6 weeks post-anterior cruciate ligament transection. Caffeic acid phenethyl ester (CAPE) was injected intraperitoneally to inhibit NF-κB activation. All rabbits were sacrificed after 8 weeks postoperative. Enzyme-linked immunosorbent assays were performed to determine interleukin 1β (IL-1β) and prostaglandin E2 (PGE2) concentrations in the synovial fluid, Indian ink staining was performed for gross morphological assessment, and hematoxylin and eosin staining and toluidine blue staining were performed for histological assessment. RESULTS Compared with L-PRP, P-PRP injections achieved better outcomes regarding the prevention of cartilage destruction, preservation of cartilaginous matrix, and reduction of IL-1β and PGE2 concentrations. CAPE injections reversed the increased IL-1β and PGE2 concentrations in the synovial fluid after L-PRP injections and improved the outcome of L-PRP injections to a level similar to P-PRP injections, while they had no influence on the therapeutic efficacy of P-PRP injections. CONCLUSIONS Concentrated leukocytes in L-PRP may release increased levels of pro-inflammatory cytokines to activate the NF-κB signaling pathway, to counter the beneficial effects of growth factors on osteoarthritic cartilage, and finally, result in a inferior efficacy of L-PRP to P-PRP for the treatment of osteoarthritis.

Canine toys and training devices as sources of exposure to phthalates and bisphenol A: quantitation of chemicals in leachate and in vitro screening for endocrine activity.

PubMed

Wooten, Kimberly J; Smith, Philip N

2013-11-01

Chewing and mouthing behaviors exhibited by pet dogs are likely to lead to oral exposures to a variety of environmental chemicals. Products intended for chewing and mouthing uses include toys and training devices that are often made of plastics. The goal of the current study was to determine if a subset of phthalates and bisphenol A (BPA), endocrine disrupting chemicals commonly found in plastics, leach out of dog toys and training devices (bumpers) into synthetic canine saliva. In vitro assays were used to screen leachates for endocrine activity. Bumper leachates were dominated by di-2-ethylhexyl phthalate (DEHP) and BPA, with concentrations reaching low μg mL(-1) following short immersions in synthetic saliva. Simulated chewing of bumpers during immersion in synthetic saliva increased concentrations of phthalates and BPA as compared to new bumpers, while outdoor storage had variable effects on concentrations (increased DEHP; decreased BPA). Toys leached substantially lower concentrations of phthalates and BPA, with the exception of one toy which leached considerable amounts of diethyl phthalate. In vitro assays indicated anti-androgenic activity of bumper leachates, and estrogenic activity of both bumper and toy leachates. These results confirm that toys and training devices are potential sources of exposure to endocrine disrupting chemicals in pet dogs. Copyright © 2013 Elsevier Ltd. All rights reserved.

Molecular speciation and tissue compartmentation of zinc in durum wheat grains with contrasting nutritional status.

PubMed

Persson, Daniel Pergament; de Bang, Thomas C; Pedas, Pai R; Kutman, Umit Baris; Cakmak, Ismail; Andersen, Birgit; Finnie, Christine; Schjoerring, Jan K; Husted, Søren

2016-09-01

Low concentration of zinc (Zn) in the endosperm of cereals is a major factor contributing to Zn deficiency in human populations. We have investigated how combined Zn and nitrogen (N) fertilization affects the speciation and localization of Zn in durum wheat (Triticum durum). Zn-binding proteins were analysed with liquid chromatography ICP-MS and Orbitrap MS(2) , respectively. Laser ablation ICP-MS with simultaneous Zn, sulphur (S) and phosphorus (P) detection was used for bioimaging of Zn and its potential ligands. Increasing the Zn and N supply had a major impact on the Zn concentration in the endosperm, reaching concentrations higher than current breeding targets. The S concentration also increased, but S was only partly co-localized with Zn. The mutual Zn and S enrichment was reflected in substantially more Zn bound to small cysteine-rich proteins (apparent size 10-30 kDa), whereas the response of larger proteins (apparent size > 50 kDa) was only modest. Most of the Zn-responsive proteins were associated with redox- and stress-related processes. This study offers a methodological platform to deepen the understanding of processes behind endosperm Zn enrichment. Novel information is provided on how the localization and speciation of Zn is modified during Zn biofortification of grains. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Arsenic trioxide at conventional dosage does not aggravate hemorrhage in the first-line treatment of adult acute promyelocytic leukemia.

PubMed

Cui, Wen; Wang, Jin; Nie, Rui-Min; Zhao, Ling-Ling; Gao, Meng-Qing; Zhu, Hong-Ming; Chen, Li; Hu, Jiong; Li, Jun-Min; Shen, Zhi-Xiang; Wang, Zhen-Yi; Chen, Sai-Juan; Chen, Zhu; Wang, Kan-Kan; Xi, Xiao-Dong; Mi, Jian-Qing

2018-04-01

The arsenic trioxide (ATO) plus all-trans retinoic acid (ATRA) therapy has demonstrated a tremendous success in the first-line treatment of acute promyelocytic leukemia (APL). Actually, early death (ED) is currently thought as a major challenge in APL. ATO has been reported to inhibit platelet function in vitro, and whether it increases the ED rate by exacerbating the hemorrhagic symptoms remains to be investigated. Effects of ATO on platelet aggregation and adhesion were evaluated in vitro and in thirty-two complete remission (CR) and four newly diagnosed APL patients. Furthermore, concentrations of plasma total arsenic were monitored in APL patients via ICP-MS. The inhibition of platelet function, either aggregation or adhesion, did occur in vitro when the concentration of ATO reached 2 μmol/L. However, in CR APL patients receiving ATO with normal platelet count, the platelets responded normally when being activated and so did those in the newly diagnosed patients with thrombocytopenia. Our data further showed that the conventional dosage of ATO reached a plasma concentration substantially below the required concentration to inhibit platelets. In the first-line treatment of APL, the use of ATO is safe and effective and does not compromise the hemostatic potential that may eventually increase ED rate. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Non-Smoker Exposure to Secondhand Cannabis Smoke. I. Urine Screening and Confirmation Results

PubMed Central

Cone, Edward J.; Bigelow, George E.; Herrmann, Evan S.; Mitchell, John M.; LoDico, Charles; Flegel, Ronald; Vandrey, Ryan

2015-01-01

Increased cannabis potency has renewed concerns that secondhand exposure to cannabis smoke can produce positive drug tests. A systematic study was conducted of smoke exposure on drug-free participants. Six experienced cannabis users smoked cannabis cigarettes (5.3% THC in Session 1 and 11.3% THC in Sessions 2 and 3) in a sealed chamber. Six non-smokers were seated with smokers in an alternating manner. Sessions 1 and 2 were conducted with no ventilation and ventilation was employed in Session 3. Non-smoking participant specimens (collected 0–34 h) were analyzed with four immunoassays at different cutoff concentrations (20, 50, 75 and 100 ng/mL) and by GC-MS (LOQ = 0.75 ng/mL). No presumptive positives occurred for non-smokers at 100 and 75 ng/mL; a single positive occurred at 50 ng/mL; and multiple positives occurred at 20 ng/mL. Maximum THCCOOH concentrations by GC-MS for non-smokers ranged from 1.3 to 57.5 ng/mL. THCCOOH concentrations generally increased with THC potency, but room ventilation substantially reduced exposure levels. These results demonstrate that extreme cannabis smoke exposure can produce positive urine tests at commonly utilized cutoff concentrations. However, positive tests are likely to be rare, limited to the hours immediately post-exposure, and occur only under environmental circumstances where exposure is obvious. PMID:25326203