Science.gov

Sample records for acid deposition damage

  1. ATMOSPHERIC ACID DEPOSITION DAMAGE TO PAINTS

    EPA Science Inventory

    Available data from laboratory and field studies of damage to paints by erosion have been analyzed to develop an atmospheric acid deposition damage function for exterior house paints containing calcium carbonate or silicate extenders. Regression analysis coefficients associated w...

  2. Acid Deposition

    EPA Science Inventory

    This indicator presents acid deposition trends in the contiguous U.S. from 1989 to 2007. Data are broken down by wet and dry deposition and deposition of nitrogen and sulfur compounds. Acid deposition is particularly damaging to lakes, streams, and forests and the plants and a...

  3. Spectral Characterization of Suspected Acid Deposition Damage in Red Spruce (picea Rubens) Stands from Vermont

    NASA Technical Reports Server (NTRS)

    Vogelmann, J. E.; Rock, B. N.

    1985-01-01

    In an attempt to demonstrate the utility of remote sensing systems to monitor sites of suspected acid rain deposition damage, intensive field activities, coupled with aircraft overflights, were centered on red spruce stands in Vermont during August and September of 1984. Remote sensing data were acquired using the Airborne Imaging Spectrometer, Thematic Mapper Simulator, Barnes Model 12 to 1000 Modular Multiband Radiometer and Spectron Engineering Spectrometer (the former two flown on the NASA C-130; the latter two on A Bell UH-1B Iroquois Helicopter). Field spectral data were acquired during the week of the August overflights using a high spectral resolution spectrometer and two broad-band radiometers. Preliminary analyses of these data indicate a number of spectral differences in vegetation between high and low damage sites. Some of these differences are subtle, and are observable only with high spectral resolution sensors; others are less subtle and are observable using broad-band sensors.

  4. CHARACTERIZATION OF PAINTED SURFACES IN THE UNITED STATES FROM THE PERSPECTIVE OF POTENTIAL DAMAGE FROM ACIDIC DEPOSITION

    EPA Science Inventory

    Data on the types and applications of exterior paints used in the United States are reviewed from the perspective of potential damage by air pollution or acidic deposition. The data indicate that, of the painted structures in the U.S., the costs of painting residential buildings ...

  5. Valuation of damages to recreational trout fishing in the Upper Northeast due to acidic deposition

    SciTech Connect

    Englin, J.E.; Cameron, T.A.; Mendelsohn, R.E.; Parsons, G.A.; Shankle, S.A.

    1991-04-01

    This report documents methods used to estimate economic models of changes in recreational fishing due to the acidic deposition. The analysis was conducted by Pacific Northwest Laboratory (PNL) and its subcontractors for the US Environmental Protection Agency (EPA) and the US Department of Energy (DOE) in support of the National Acidic Precipitation Assessment Program (NAPAP). The primary data needed to estimate these models were collected in the 1989 Aquatic Based Recreation Survey (ABRS), which was jointly funded by the DOE and the EPA's Office of Policy Planning and Evaluation. 11 refs., 5 figs., 15 tabs.

  6. Stress assessment and spectral characterization of suspected acid deposition damage in red spruce (Picea Rubens) from Vermont

    NASA Technical Reports Server (NTRS)

    Rock, B. N.; Vogelmann, J. E.

    1985-01-01

    The effects of acid deposition on Picea rubens are studied. The Picea rubens located at Camels Hump Mt., Mt. Ascutney, and Ripton, VT were analyzed using stress level evaluations, in situ spectral data, pressure bomb analysis, and aircraft sensors. Spruce stress per circular plot and percent spruce mortality are calculated. The relation between stress levels and elevation and exposure and weather patterns is examined. It is observed that variations in the reflectance curves of the foliage and branches are related to cellular health, the type of cellular arrangement, and the degree of leaf tissue hydration; the leaf and twig specimens from high stress sites are more reflective in the red portion of the visible and less reflective in the NIR portion of the spectrum. The pressure bomb data reveal that the xylem water tension is higher in specimens from high stress sites. It is noted that remote sensing permits discrimination and mapping of suspected acid deposition damage.

  7. ADVANCES IN CONTROL TECHNOLOGY FOR ACID DEPOSITION

    EPA Science Inventory

    Causes and effects of acid deposition are the subject of widespread discussion both in the U.S. and Europe. Two major concerns are the acidification of lakes and streams, and forest damage. The proposed mechanism for acidification of lakes and streams is the deposition of acidic ...

  8. Acid deposition in Maryland: Implications of the results of the National Acid Precipitation Assessment Program

    SciTech Connect

    DeMuro, J.; Bowmann, M.; Ross, J.; Blundell, C.; Price, R.

    1991-07-01

    Acid deposition, commonly referred to as 'acid rain,' is a major global environmental concern. Acid deposition has reportedly resulted in damage to aquatic, terrestrial, and physical resources and has potentially adverse effects on human health. A component of the Maryland acid deposition program is the preparation of an annual report that summarizes yearly activities and costs of ongoing acid deposition research and monitoring programs.

  9. DRY DEPOSITION MODULE FOR REGIONAL ACID DEPOSITION

    EPA Science Inventory

    Methods to compute surface dry deposition velocities for sulfur dioxide, sulfate, ozone, NO plus NO2, and nitric acid vapor over much of the North American continent have been developed for use with atmospheric numerical models of long-range transport and deposition. The resultin...

  10. SOIL REACTION AND ACIDIC DEPOSITION

    EPA Science Inventory

    This chapter discusses the major chemical processes by which acidic deposition interacts with soils. he focus is on forest soils, as the effects of acidic deposition on soils used for production of food and fiber are generally small compared to effects of agricultural practices s...

  11. Acid deposition: Atmospheric processes in Eastern North America

    SciTech Connect

    Not Available

    1983-01-01

    This report examines scientific evidence on the relationship between emissions of acid-forming pollutants and damage to sensitive ecosystems from acid rain and other forms of acid deposition. The report's conclusions represent the most authoritative statement yet that reductions in emissions of these pollutants will result in proportional reductions in acid rain.

  12. ACID DEPOSITION AND FOREST DECLINE

    EPA Science Inventory

    The location, topography and other characteristics of the high-elevation forests of eastern North America cause them to be receptors of high levels of acid deposition and airborn trace metals. No other major forested areas in the U.S. are subjected to such intensely acid cloud mo...

  13. (Acidic deposition and the environment)

    SciTech Connect

    Garten, C.T.; Lindberg, S.E.; Van Miegroet, H.

    1990-10-24

    The travelers presented several papers at the Fourth International Conference on Acidic Deposition. These covered the following topics: atmospheric chemistry and deposition of airborne nitrogen compounds, soil solution chemistry in high-elevation spruce forests, and forest throughfall measurements for estimating total sulfur deposition to ecosystems. In addition, S. E. Lindberg was invited to organize and chair a conference session on Throughfall and Stemflow Experiments, and to present an invited lecture on Atmospheric Deposition and Canopy Interactions of Metals and Nitrogen in Forest Ecosystems: The Influence of Global Change'' at the 110th Anniversary Celebration of the Free University of Amsterdam.

  14. (International conference on acidic deposition)

    SciTech Connect

    McLaughlin, S.B. Jr.

    1990-10-05

    The traveler took the opportunity to participate in a mini-sabbatical at the Institute of Terrestrial Ecology (ITE) in Edinburgh, Scotland, as a part of planned travel to Glasgow, Scotland, to attend the International Conference on Acidic Precipitation. The purpose of the sabbatical was to provide quality time for study and interchange of ideas with scientists at ITE working on physiological effects of acidic deposition and to allocate significant time for writing and synthesizing of results of physiological studies from the National Forest Response Program's Spruce/Fir Research Cooperative. The study focused on the very significant cytological and physiological effects of calcium deficiency in trees, a response that appears to be amplified in spruce by acidic deposition.

  15. EPA releases study describing potential acid rain damage

    SciTech Connect

    Not Available

    1989-11-01

    The U.S. Environmental Protection Agency's acid rain researchers on August 24 offered evidence that if sulfur emissions are not reduced in the future, aquatic systems in the South will suffer damage from acid rain. Evidence also indicates that reductions in sulfur emissions could improve the health of damaged lakes in the Northeast. The study Future Effects of Long-Term Sulfur Deposition on Surface Water Chemistry: The Direct/Delayed Response Project, developed 50-year projections of watershed quality under three plausible acidic deposition, or acid rain, scenarios. Three areas were studied - the Northeast, comprising all of New England and parts of New York and Pennsylvania; the Mid-Appalachian Region, covering much of Pennsylvania, Maryland, Virginia, and West Virginia; and the Southern Blue Ridge Province, an area covering parts of North Carolina, Tennessee, South Carolina and Georgia. The study is a key element in the closing months of the 10-year National Acid Precipitation Assessment Program.

  16. Acid deposition in east Asia

    SciTech Connect

    Phadnis, M.J.; Carmichael, G.R.; Ichikawa, Y.

    1996-12-31

    A comparison between transport models was done to study the acid deposition in east Asia. The two models in question were different in the way the treated the pollutant species and the way simulation was carried out. A single-layer, trajectory model with simple (developed by the Central Research Institute of Electric Power Industry (CRIEPI), Japan) was compared with a multi-layered, eulerian type model (Sulfur Transport Eulerian Model - II [STEM-II]) treating the chemical processes in detail. The acidic species used in the simulation were sulfur dioxide and sulfate. The comparison was done for two episodes: each a month long in winter (February) and summer (August) of 1989. The predicted results from STEM-II were compared with the predicted results from the CRIEPI model as well as the observed data at twenty-one stations in Japan. The predicted values from STEM-II were similar to the ones from the CRIEPI results and the observed values in regards to the transport features. The average monthly values of SO{sub 2} in air, sulfate in air and sulfate in precipitation were in good agreement. Sensitivity studies were carried out under different scenarios of emissions, dry depositions velocities and mixing heights. The predicted values in these sensitivity studies showed a strong dependence on the mixing heights. The predicted wet deposition of sulfur for the two months is 0.7 gS/m2.mon, while the observed deposition is around 1.1 gS/m2.mon. It was also observed that the wet deposition on the Japan sea side of the islands is more than those on the Pacific side and the Okhotsk sea, mainly because of the continental outflow of pollutant air masses from mainland China and Korea. The effects of emissions from Russia and volcanoes were also evaluated.

  17. ACIDIC DEPOSITION AND CISTERN DRINKING WATER SUPPLIES

    EPA Science Inventory

    The Water quality charecteristics, including the trace element Cd, cu, Pb, and Zn, in rainwater cistern supplies representing an area receiving acidic deposition were compared to cistern water chemistry in a control area that does not receive a significant input of acidic deposit...

  18. Mesoscale acid deposition modeling studies

    NASA Technical Reports Server (NTRS)

    Kaplan, Michael L.; Proctor, F. H.; Zack, John W.; Karyampudi, V. Mohan; Price, P. E.; Bousquet, M. D.; Coats, G. D.

    1989-01-01

    The work performed in support of the EPA/DOE MADS (Mesoscale Acid Deposition) Project included the development of meteorological data bases for the initialization of chemistry models, the testing and implementation of new planetary boundary layer parameterization schemes in the MASS model, the simulation of transport and precipitation for MADS case studies employing the MASS model, and the use of the TASS model in the simulation of cloud statistics and the complex transport of conservative tracers within simulated cumuloform clouds. The work performed in support of the NASA/FAA Wind Shear Program included the use of the TASS model in the simulation of the dynamical processes within convective cloud systems, the analyses of the sensitivity of microburst intensity and general characteristics as a function of the atmospheric environment within which they are formed, comparisons of TASS model microburst simulation results to observed data sets, and the generation of simulated wind shear data bases for use by the aviation meteorological community in the evaluation of flight hazards caused by microbursts.

  19. Effects of acid deposition on agricultural production

    SciTech Connect

    Moskowitz, P.D.; Medeiros, W.H.; Oden, N.L.; Thode, H.C. Jr.; Coveney, E.A.; Jacobson, J.S.; Rosenthal, R.E.; Evans, L.S.; Lewin, K.F.; Allen, F.L.

    1985-09-01

    A preliminary assessment, both qualitative and quantitative, was carried out on the effects of acid deposition on agriculture. An inventory was made of US crops exposed to different acid deposition levels in 1982. Most crops (valued at more than $50 billion) were exposed to annual average acid deposition levels greater than pH 4.6, but crops worth more than $220 billion were exposed to even lower pH levels. Published results of experiments on crop response to acid deposition have not identified any single crop as being consistently sensitive, and suggest that present levels of acidic precipitation in the US are not significantly affecting growth and yield of crops. Because relatively few experiments appropriate to a quantitative acid deposition assessment have been conducted, the quantitative section is necessarily based on a restricted data set. Corn, potatoes, and soybeans have been studied in experimental environments which simulate agronomic conditions and which have adequate statistical power for yield estimates; only some varieties of soybeans have demonstrated statistically significant sensitivity to acid deposition.

  20. ACIDIC DEPOSITION PHENOMENON AND ITS EFFECTS: CRITICAL ASSESSMENT DOCUMENT

    EPA Science Inventory

    The Acidic Deposition Phenomenon and Its Effects: Critical Assessment Document (CAD) is a summary, integration, and interpretation of the current scientific understanding of acidic deposition. It is firmly based upon The Acidic Deposition Phenomenon and Its Effects: Critical Asse...

  1. Florida acid deposition study - an overview

    SciTech Connect

    Henderson, C.D.; Hendrickson, E.R.

    1983-01-01

    Comprehensive literature searches were performed in the areas of source attribution and long-range transport and ecological and material effects. The literature searches were designed to determine the impacts of acid deposition that are specific to Florida. In January 1982 the results of Phase I programs were issued. These reports were: (1) Monitoring Program Phase I Summary Report; (2) Source Attribution Phase I Summary Report; and (3) A Literature Review of the Ecological and Materials Effects of Acid Deposition.

  2. Acidic deposition and soil processes

    SciTech Connect

    Newton, R.M.; April, R.H.

    1985-08-01

    The results of the Integrated Lake-Watershed Acidification Study (ILWAS) show that the sensitivity of a watershed to surface water acidification is determined by the flow paths of water through the terrestrial system. If the water infiltrates through the soils into the groundwater system, acid neutralization occurs through weathering reactions involving minerals in the soils and till. Runoff and shallow interflow result in acid surface waters. Flow paths are determined in the ILWAS watersheds by the thickness of the glacial till. Complete neutralization can occur even in areas underlain by sensitive bedrock if the flow path through the mineral horizons is long enough. This appears to hold even in areas outside of the Adirondacks. 11 references, 5 figures.

  3. Effects of acid deposition on terrestrial ecosystems and their rehabilitation strategies in China.

    PubMed

    Feng, Zong-wei; Miao, Hong; Zhang, Fu-zhu; Huang, Yi-zong

    2002-04-01

    South China has become the third largest region associated with acid deposition following Europe and North America, the area subject to damage by acid deposition increased from 1.75 million km2 in 1985 to 2.8 million km2 in 1993. Acid deposition has caused serious damage to ecosystem. Combined pollution of acid rain and SO2 showed the obvious multiple effects on crops. Vegetable was more sensitive to acid deposition than foodstuff crops. Annual economic loss of crops due to acid deposition damage in eleven provinces of south China was 4.26 billion RMB Yuan. Acid deposition caused serious damage to forest. Annual economic loss of wood volume was about 1.8 billion RMB Yuan and forest ecological benefit loss 16.2 billion in eleven provinces of south China. Acid deposition in south China was typical "sulfuric acid type". According to the thoughts of sustainable development, some strategies were brought forward as follows: (1) enhancing environmental management, specifying acid-controlling region, controlling and abating the total emission amount of SO2; (2) selecting practical energy technologies of clean coal, for example, cleansing and selecting coal, sulfur-fixed-type industrial briqutting, abating sulfur from waste gas and so on; (3) developing other energy sources to replace coal, including water electricity, atomic energy and the new energy such as solar energy, wind energy and so on; (4) in acid deposition region of south China, selecting acid-resistant type of crop and tree to decrease agricultural losses, planting more green fertilizer crops, using organic fertilizers and liming, in order to improve buffer capacities of soil. PMID:12046292

  4. RESULTS FROM THE MOUNTAIN ACID DEPOSITION PROGRAM

    EPA Science Inventory

    The Mountain Acid Deposition Program (MADPro) was initiated in 1993 as part of the research necessary to support the objectives of the Clean Air Status and Trends Network (CASTNet), which was created to address the. requirements of the Clean Air Act Amendments (CAAA). The main ob...

  5. Acid deposition control benefits as problematic

    SciTech Connect

    Crocker, T.D.

    1985-01-01

    The author argues that the government's mistaken beliefs downgrade the benefits of acid deposition control, and may misdirect research of the effects of acid rain upon natural and human systems. It can be argued as to whether or not the factors (generally existing prices and yield changes from current standing stocks of environmental goods) upon which the $5 billion estimate for control was built have a major or minor influence upon the true economic consequences of acid deposition. As the application of Bayes' rule demonstrates, any lessening in arbitrariness of numerical assignments to the factors could lead to a major revision in the estimate. Assessment stories probably contribute to the paralysis of political will even though their truth value is small.

  6. CASTNet mountain acid deposition monitoring program

    SciTech Connect

    Bowser, J.J.; Anderson, J.B.; Edgerton, E.S.; Mohnen, V.; Baumgardener, R.

    1994-12-31

    Concern over the influence of air pollution on forest decline has led the USEPA to establish the Mountain Acid Deposition Monitoring Program (MADMP) to quantify total deposition at high altitudes, i.e., above cloud base. Clouds can be a major source of atmospheric deposition to sensitive, mountain ecosystems. This program is a part of the Clean Air Status and Trends Network (CASTNet), a national assessment of the effects of the 1990 Clean Air Act. The objectives of MADMP are to estimate total deposition, measure cloud chemistry, and characterize spacial and temporal trends at four selected high altitude sites in the Eastern US. Four MADMP sites have been established for the 1994 field season: Clingman`s Dome, Great Smoky Mountain Nat. Park, TN; Slide Mountain, Catskill State Park, NY; Whiteface Mountain, Adirondack State Park, NY; and Whitetop Mountain, Mt. Rogers Nat`l Recreational Area, VA. An automated cloud collection system will be utilized in combination with continuous measurements of cloud liquid water content in order to estimate cloudwater deposition. Other relevant data will include continuous meteorological measurements, ozone and sulfur dioxide concentrations, wet deposition from rainfall analysis, and dry deposition from filter pack analysis. Quality assurance and quality control measures will be employed to maximize accuracy and precision.

  7. Acidic deposition and surface water chemistry

    NASA Astrophysics Data System (ADS)

    Church, M. R.

    A pair of back-to-back (morning and afternoon) hydrology sessions, held December 10, 1987, at the AGU Fall Meeting in San Francisco, Calif., covered “Predicting the Effects of Acidic Deposition on Surface Water Chemistry.” The combined sessions included four invited papers, 12 contributed papers, and a panel discussion at its conclusion. The gathering dealt with questions on a variety of aspects of modeling the effects of acidic deposition on surface water chemistry.Contributed papers included discussions on the representation of processes in models as well as limiting assumptions in model application (V. S. Tripathi et al., Oak Ridge National Laboratory, Oak Ridge, Tenn., and E. C. Krug, Illinois State Water Survey, Champaign), along with problems in estimating depositional inputs to catchments and thus inputs to be used in the simulation of catchment response (M. M. Reddy et al., U.S. Geological Survey, Lakewood, Colo.; and E. A. McBean, University of Waterloo, Waterloo, Canada). L. A. Baker et al. (University of Minnesota, Minneapolis) dealt with the problem of modeling seepage lake systems, an exceedingly important portion of the aquatic resources in Florida and parts of the upper U.S. Midwest. J. A. Hau and Y. Eckstein (Kent State University, Kent, Ohio) considered equilibrium modeling of two northern Ohio watersheds that receive very different loads of acidic deposition but are highly similar in other respects.

  8. (Acidic deposition: Its nature and impacts)

    SciTech Connect

    Cook, R.B.; Turner, R.S. ); Ryan, P.F. )

    1990-10-18

    The travelers presented papers on various aspects of modeling performed as part of the US National Acidic Precipitation Assessment Program (NAPAP) at the Fourth International Conference on Acidic Deposition: Its Nature and Impacts. The meeting was sponsored by the Royal Society of Edinburgh and was attended by over 800 scientists, primarily from Europe and North America. The conference focused on nine aspects of the nature and impacts of atmospheric pollutants, including ozone: chemistry of atmospheric pollutants; processes controlling the deposition of pollutants; effects of pollutants on soils; physiology of plant responses to pollutants; effects of pollutants in agricultural and natural or seminatural ecosystems; atmospheric pollutants and forests; effects of pollutants on the chemistry of freshwater streams and lakes; effects of pollutants on freshwater plants and animals; and effects of pollutants, indoors and outdoors, on materials and buildings.

  9. Acidic Depositions: Effects on Wildlife and Habitats

    USGS Publications Warehouse

    1993-01-01

    The phenomenon of 'acid rain' is not new; it was recognized in the mid-1800s in industrialized Europe. In the 1960s a synthesis of information about acidification began in Europe, along with predictions of ecological effects. In the U.S. studies of acidification began in the 1920s. By the late 1970s research efforts in the U.S. and Canada were better coordinated and in 1980 a 10-year research program was undertaken through the National Acid Precipitation Assessment Plan (NAPAP) to determine the causes and consequences of acidic depositions. Much of the bedrock in the northeastern U.S. and Canada contains total alkalinity of 20 kg/ha/yr of wet sulphate depositions and are vulnerable to acidifying processes. Acidic depositions contribute directly to acidifying processes of soil and soil water. Soils must have sufficient acid-neutralizing capacity or acidity of soil will increase. Natural soil-forming processes that lead to acidification can be accelerated by acidic depositions. Long-term effects of acidification are predicted, which will reduce soil productivity mainly through reduced availability of nutrients and mobilization of toxic metals. Severe effects may lead to major alteration of soil chemistry, soil biota, and even loss of vegetation. Several species of earthworms and several other taxa of soil-inhabiting invertebrates, which are important food of many vertebrate wildlife species, are affected by low pH in soil. Loss of canopy in declining sugar maples results in loss of insects fed on by certain neotropical migrant bird species. No definitive studies categorically link atmospheric acidic depositions with direct or indirect effects on wild mammals. Researchers have concentrated on vegetative and aquatic effects. Circumstantial evidence suggests that effects are probable for certain species of aquatic-dependent mammals (water shrew, mink, and otter) and that these species are at risk from the loss of foods or contamination of these foods by metals

  10. Damage evaluation in graphene underlying atomic layer deposition dielectrics

    PubMed Central

    Tang, Xiaohui; Reckinger, Nicolas; Poncelet, Olivier; Louette, Pierre; Ureña, Ferran; Idrissi, Hosni; Turner, Stuart; Cabosart, Damien; Colomer, Jean-François; Raskin, Jean-Pierre; Hackens, Benoit; Francis, Laurent A.

    2015-01-01

    Based on micro-Raman spectroscopy (μRS) and X-ray photoelectron spectroscopy (XPS), we study the structural damage incurred in monolayer (1L) and few-layer (FL) graphene subjected to atomic-layer deposition of HfO2 and Al2O3 upon different oxygen plasma power levels. We evaluate the damage level and the influence of the HfO2 thickness on graphene. The results indicate that in the case of Al2O3/graphene, whether 1L or FL graphene is strongly damaged under our process conditions. For the case of HfO2/graphene, μRS analysis clearly shows that FL graphene is less disordered than 1L graphene. In addition, the damage levels in FL graphene decrease with the number of layers. Moreover, the FL graphene damage is inversely proportional to the thickness of HfO2 film. Particularly, the bottom layer of twisted bilayer (t-2L) has the salient features of 1L graphene. Therefore, FL graphene allows for controlling/limiting the degree of defect during the PE-ALD HfO2 of dielectrics and could be a good starting material for building field effect transistors, sensors, touch screens and solar cells. Besides, the formation of Hf-C bonds may favor growing high-quality and uniform-coverage dielectric. HfO2 could be a suitable high-K gate dielectric with a scaling capability down to sub-5-nm for graphene-based transistors. PMID:26311131

  11. Damage evaluation in graphene underlying atomic layer deposition dielectrics.

    PubMed

    Tang, Xiaohui; Reckinger, Nicolas; Poncelet, Olivier; Louette, Pierre; Ureña, Ferran; Idrissi, Hosni; Turner, Stuart; Cabosart, Damien; Colomer, Jean-François; Raskin, Jean-Pierre; Hackens, Benoit; Francis, Laurent A

    2015-01-01

    Based on micro-Raman spectroscopy (μRS) and X-ray photoelectron spectroscopy (XPS), we study the structural damage incurred in monolayer (1L) and few-layer (FL) graphene subjected to atomic-layer deposition of HfO2 and Al2O3 upon different oxygen plasma power levels. We evaluate the damage level and the influence of the HfO2 thickness on graphene. The results indicate that in the case of Al2O3/graphene, whether 1L or FL graphene is strongly damaged under our process conditions. For the case of HfO2/graphene, μRS analysis clearly shows that FL graphene is less disordered than 1L graphene. In addition, the damage levels in FL graphene decrease with the number of layers. Moreover, the FL graphene damage is inversely proportional to the thickness of HfO2 film. Particularly, the bottom layer of twisted bilayer (t-2L) has the salient features of 1L graphene. Therefore, FL graphene allows for controlling/limiting the degree of defect during the PE-ALD HfO2 of dielectrics and could be a good starting material for building field effect transistors, sensors, touch screens and solar cells. Besides, the formation of Hf-C bonds may favor growing high-quality and uniform-coverage dielectric. HfO2 could be a suitable high-K gate dielectric with a scaling capability down to sub-5-nm for graphene-based transistors. PMID:26311131

  12. Emerging acid deposition research and monitoring issues

    SciTech Connect

    Birnbaum, R.

    1997-12-31

    The research baselines established for acid rain in the 1980s position scientists and policy makers to evaluate the environmental effectiveness of the acid rain control program and to test the variety of scientific hypotheses made regarding the chemical, transport and biological processes involved in acidic deposition. Several new research questions have evolved. How effective are the emissions reductions? What is the residual risk? How have ecological recovery rates been affected and what other environmental factors influence recovery? What are the critical requirements to measure ecological change including the extent and rate while also capturing the extent and severity of emerging ecological stressors (such as watershed nitrogen saturation)? These and other questions are currently being synthesized within and outside of EPA to develop a long-term strategy to provide guidance to emerging research and monitoring issues.

  13. Photosynthetic and growth responses of Schima superba seedlings to sulfuric and nitric acid depositions.

    PubMed

    Yao, Fang-Fang; Ding, Hui-Ming; Feng, Li-Li; Chen, Jing-Jing; Yang, Song-Yu; Wang, Xi-Hua

    2016-05-01

    A continuing rise in acid deposition can cause forest degradation. In China, acid deposition has converted gradually from sulfuric acid deposition (SAD) to nitric acid deposition (NAD). However, the differing responses of photosynthesis and growth to depositions of sulfuric vs. nitric acid have not been well studied. In this study, 1-year-old seedlings of Schima superba, a dominant species in subtropical forests, were treated with two types of acid deposition SO4 (2-)/NO3 (-) ratios (8:1 and 0.7:1) with two applications (foliar spraying and soil drenching) at two pH levels (pH 3.5 and pH 2.5) over a period of 18 months. The results showed that the intensity, acid deposition type, and spraying method had significant effects on the physiological characteristics and growth performance of seedlings. Acid deposition at pH 2.5 via foliar application reduced photosynthesis and growth of S. superba, especially in the first year. Unlike SAD, NAD with high acidity potentially alleviated the negative effects of acidity on physiological properties and growth, probably due to a fertilization effect that improved foliar nitrogen and chlorophyll contents. Our results suggest that trees were damaged mainly by direct acid stress in the short term, whereas in the long term, soil acidification was also likely to be a major risk to forest ecosystems. Our data suggest that the shift in acid deposition type may complicate the ongoing challenge of anthropogenic acid deposition to ecosystem stability. PMID:26797956

  14. Ancillary effects of selected acid deposition control policies

    SciTech Connect

    Moe, R.J.; Lyke, A.J.; Nesse, R.J.

    1986-08-01

    NAPAP is examining a number of potential ways to reduce the precursors (sulfur dioxide and nitrogen oxides) to acid deposition. However, the policies to reduce acid deposition will have other physical, biological and economic effects unrelated to acid deposition. For example, control policies that reduce sulfur dioxide emissions may also increase visibility. The effects of an acid deposition policy that are unrelated to acid deposition are referred to as ''ancillary'' effects. This reserch identifies and characterizes the principle physical and economic ancillary effects associated with acid deposition control and mitigation policies. In this study the ancillary benefits associated with four specific acid deposition policy options were investigated. The four policy options investigated are: (1) flue gas desulfurization, (2) coal blending or switching, (3) reductions in automobile emissions of NO/sub x/, and (4) lake liming. Potential ancillary benefits of each option were identified and characterized. Particular attention was paid to the literature on economic valuation of potential ancillary effects.

  15. Deposition of salicylic acid into hamster sebaceous.

    PubMed

    Motwani, M R; Rhein, L D; Zatz, J L

    2004-01-01

    In an earlier paper, we identified vehicles that are miscible with sebum, using differential scanning calorimetry (DSC). In this paper, the potential of these vehicles to deliver salicylic acid (SA) into the sebum-filled follicles of hamster ears is examined. The main objective of this study is to correlate the melting transitions of a model sebum with the follicular delivery of SA, using two different types of vehicles (fatty and polar). Generally, the fatty vehicles show higher deposition than the polar vehicles. Follicular delivery of salicylic acid correlates well with its solubility in the respective vehicles. This extent of deposition also shows a relationship with the effect of the vehicle on thermal behavior of the model sebum. The nature of the relationship depends on the vehicle (polar or fatty) tested. We conclude that DSC could be used to identify appropriate vehicles for drugs whose follicular delivery depends on solubility. The results also suggest that delivery into the sebaceous glands occurs by two different mechanisms, depending upon the polarity of the vehicle and the physicochemical properties of the drug. The results of these experiments are further extended to investigate follicular delivery of SA from two different types of oil-in-water emulsion formulations. From these studies we conclude that either increasing the volume of the oil phase or changing the emulsion to a water-in-oil emulsion would increase follicular deposition. Our research highlights the role of sebum, its compatibility with drug molecules, and vehicle selection in the transport of drugs into the follicles. The overall results of these experiments provide a reasonable understanding of the mechanisms underlying the transport of drugs to, and subsequently through, the sebaceous follicle. PMID:15645108

  16. How Acid Reflux Disease Damages Teeth

    MedlinePlus

    ... an advanced stage of destruction." The potential of hydrogen, or pH, is a standard way to measure ... January 2012 Related Articles: Tooth Erosion Sports and Energy Drinks Responsible for Irreversible Damage to Teeth What ...

  17. Localized planarization of optical damage using laser-based chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Matthews, Manyalibo J.; Elhadj, Selim; Guss, Gabe M.; Sridharan, Arun; Nielsen, Norman D.; Yoo, Jae-Hyuck; Lee, Daeho; Grigoropoulos, Costas

    2013-11-01

    We present a method to repair damaged optics using laser-based chemical vapor deposition (L-CVD). A CO2 laser is used to heat damaged silica regions and polymerize a gas precursor to form SiO2. Measured deposition rates and morphologies agree well with finite element modeling of a two-phase reaction. Along with optimizing deposition rates and morphology, we also show that the deposited silica is structurally identical to high-grade silica substrate and possesses high UV laser damage thresholds. Successful application of such a method could reduce processing costs, extend optic lifetime, and lead to more damage resistant laser optics used in high power applications.

  18. The emerging role of NO{sub x} in acid deposition

    SciTech Connect

    Price, D.A.; Birnbaum, R.E.

    1997-12-31

    The oxides of nitrogen (NO{sub x}) have long been recognized as a principal precursor to acid deposition. Until recently, however, scientific knowledge about the nature and extent of NO{sub x}`s contribution to acidity in the atmosphere and to acid deposition damages on earth has been nascent; the National Acid Precipitation Assessment Program (NAPAP) and related research during the 1980s focused primarily on the linkage between sulfur dioxide (SO{sub 2}) emissions with acid deposition. This paper summarizes an integrative assessment on the science of NO{sub x} and acid deposition and the multiple environmental benefits associated with decreases in NO{sub x} emissions from coal-fired power plants. The Acid Rain Program performed this staff assessment to support the Phase II Acid Rain NO{sub x} Emission Reduction Rule, proposed on January 19, 1996 (61 FR 1442), and the Office of Air and Radiation (OAR) Integrated NO{sub x} Strategy. Model projections from EPA`s Acid Deposition Standard Feasibility Study (October 1995) provided the initial indication of the important role of NO{sub x} in the future chronic acidification of certain sensitive watershed ecosystems. Corroborative findings from the Bear Brook Watershed Manipulation Experiment and other recent field studies are discussed. This paper also presents an overview discussion of the current state-of-knowledge with respect to NO{sub x}`s role in the acidification of forests, soils, and vegetation as well as acidic-related damage to materials and structures. Basic terms and processes such as {open_quotes}atmospheric nitrogen deposition,{close_quotes} {open_quotes}nitrogen saturation,{close_quotes} {open_quotes}chronic vs. episodic acidification,{close_quotes} and {open_quotes}direct vs. soil-mediated acidification effects{close_quotes} are defined in context so as to facilitate understanding of the emerging role of NO{sub x} in acid deposition.

  19. STATUS OF RESEARCH TO DEVELOP ACIDIC DRY DEPOSITION MONITORING CAPABILITY

    EPA Science Inventory

    Dry deposition is thought to be as important as wet deposition in acidifying ecosystems. However, at present acidic dry deposition of relevant particles and gases cannot be monitored directly in a quantitative manner. The U.S. EPA Workshop on Dry Deposition (Report No. EPA-600/9-...

  20. A new look at liming as an approach to accelerate recovery from acidic deposition effects.

    PubMed

    Lawrence, Gregory B; Burns, Douglas A; Riva-Murray, Karen

    2016-08-15

    Acidic deposition caused by fossil fuel combustion has degraded aquatic and terrestrial ecosystems in North America for over four decades. The only management option other than emissions reductions for combating the effects of acidic deposition has been the application of lime to neutralize acidity after it has been deposited on the landscape. For this reason, liming has been a part of acid rain science from the beginning. However, continued declines in acidic deposition have led to partial recovery of surface water chemistry, and the start of soil recovery. Liming is therefore no longer needed to prevent further damage, so the question becomes whether liming would be useful for accelerating recovery of systems where improvement has lagged. As more is learned about recovering ecosystems, it has become clear that recovery rates vary with watershed characteristics and among ecosystem components. Lakes appear to show the strongest recovery, but recovery in streams is sluggish and recovery of soils appears to be in the early stages. The method in which lime is applied is therefore critical in achieving the goal of accelerated recovery. Application of lime to a watershed provides the advantage of increasing Ca availability and reducing or preventing mobilization of toxic Al, an outcome that is beneficial to both terrestrial and aquatic ecosystems. However, the goal should not be complete neutralization of soil acidity, which is naturally produced. Liming of naturally acidic areas such as wetlands should also be avoided to prevent damage to indigenous species that rely on an acidic environment. PMID:27092419

  1. A new look at liming as an approach to accelerate recovery from acidic deposition effects

    USGS Publications Warehouse

    Lawrence, Gregory B.; Burns, Douglas A.; Murray, Karen

    2016-01-01

    Acidic deposition caused by fossil fuel combustion has degraded aquatic and terrestrial ecosystems in North America for over four decades. The only management option other than emissions reductions for combating the effects of acidic deposition has been the application of lime to neutralize acidity after it has been deposited on the landscape. For this reason, liming has been a part of acid rain science from the beginning. However, continued declines in acidic deposition have led to partial recovery of surface water chemistry, and the start of soil recovery. Liming is therefore no longer needed to prevent further damage, so the question becomes whether liming would be useful for accelerating recovery of systems where improvement has lagged. As more is learned about recovering ecosystems, it has become clear that recovery rates vary with watershed characteristics and among ecosystem components. Lakes appear to show the strongest recovery, but recovery in streams is sluggish and recovery of soils appears to be in the early stages. The method in which lime is applied is therefore critical in achieving the goal of accelerated recovery. Application of lime to a watershed provides the advantage of increasing Ca availability and reducing or preventing mobilization of toxic Al, an outcome that is beneficial to both terrestrial and aquatic ecosystems. However, the goal should not be complete neutralization of soil acidity, which is naturally produced. Liming of naturally acidic areas such as wetlands should also be avoided to prevent damage to indigenous species that rely on an acidic environment.

  2. Acid rain damage to carbonate stone: a quantitative assessment based on the aqueous geochemistry of rainfall runoff from stone

    USGS Publications Warehouse

    Reddy, M.M.

    1988-01-01

    An onsite experimental procedure was used to identify and quantify acid rain damage to carbonate stone, based on the change in rain runoff chemical composition. Onsite data obtained during the summer and fall of 1984 at three locations in the northeastern United States indicate that carbonate stone surface recession is related to acid deposition. -from Author

  3. Investigation of the formation of physical damage on automotive finishes due to acidic reagent exposure

    SciTech Connect

    White, D.F.; Fornes, R.E.; Gilbert, R.D.; Speer, J.A. )

    1993-10-15

    Automotive paints with clear-coat surfaces can be physically damaged by exposure to acidic reagents produced in a smog chamber designed to reproduce real environmental conditions. Visual and reflectance microscopy observations show that deposition of material formed from the reaction of the clear coat and the reagent drop occurs on the paint surface after the drop evaporates to a critical size, with the greatest deposition occurring at the edge of the drop. This type of deposition suggests a free-energy minimization process favoring the formation of stable nuclei at the reagent drop edge. With heating after the drop evaporation to stimulate exposure to the sun, a damaged area containing sulfur that is in the shape of a circular ring is observed at the location of the deposits. The majority of the visual damage appears to result from an interaction between the deposit and the paint at elevated temperatures. Results from profilometry, scanning electron microscopy, and reflectance microscopy show that the damaged areas are ring-shaped cracked blisters on the surface resulting from the clear coat separating into layers.

  4. Acid deposition and the acidification of soils and waters

    SciTech Connect

    Reuss, J.O.; Johnson, D.W.

    1985-01-01

    A conceptual model of acid deposition is presented consistent with established physicochemical principles and the bulk of available information. The authors seek to provide insight into probable long-term effects of acid deposition; a testable hypotheses; plus design and interpretation of the research. (PSB)

  5. ROCKY MOUNTAIN ACID DEPOSITION MODEL ASSESSMENT: EVALUATION OF MESOSCALE ACID DEPOSITION MODELS FOR USE IN COMPLEX TERRAIN

    EPA Science Inventory

    The report includes an evaluation of candidate meteorological models and acid deposition models. The hybrid acid deposition/air quality modeling system for the Rocky Mountains makes use of a mesoscale meteorological model, which includes a new diagnostic wind model, as a driver f...

  6. Antioxidant and DNA damage protection potentials of selected phenolic acids.

    PubMed

    Sevgi, Kemal; Tepe, Bektas; Sarikurkcu, Cengiz

    2015-03-01

    In this study, ten different phenolic acids (caffeic, chlorogenic, cinnamic, ferulic, gallic, p-hydroxybenzoic, protocatechuic, rosmarinic, syringic, and vanillic acids) were evaluated for their antioxidant and DNA damage protection potentials. Antioxidant activity was evaluated by using four different test systems named as β-carotene bleaching, DPPH free radical scavenging, reducing power and chelating effect. In all test systems, rosmarinic acid showed the maximum activity potential, while protocatechuic acid was determined as the weakest antioxidant in β-carotene bleaching, DPPH free radical scavenging, and chelating effect assays. Phenolic acids were also screened for their protective effects on pBR322 plasmid DNA against the mutagenic and toxic effects of UV and H2O2. Ferulic acid was found as the most active phytochemical among the others. Even at the lowest concentration value (0.002 mg/ml), ferulic acid protected all of the bands in the presence of H2O2 and UV. It is followed by caffeic, rosmarinic, and vanillic acids. On the other hand, cinnamic acid (at 0.002 mg/ml), gallic acid (at 0.002 mg/ml), p-hydroxybenzoic acid (at 0.002 and 0.004 mg/ml), and protocatechuic acid (at 0.002 and 0.004 mg/ml) could not protect plasmid DNA. PMID:25542528

  7. ROCKY MOUNTAIN ACID DEPOSITION MODEL ASSESSMENT: ACID RAIN MOUNTAIN MESOSCALE MODEL (ARM3)

    EPA Science Inventory

    The Acid Rain Mountain Mesoscale Model (ARM3) is a mesoscale acid deposition/air quality model that was developed for calculating incremental acid deposition (sulfur and nitrogen species) and pollutant concentration impacts in complex terrain. The model was set up for operation w...

  8. 25 CFR 169.14 - Deposit and disbursement of consideration and damages.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .... 169.14 Section 169.14 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER RIGHTS-OF-WAY OVER INDIAN LANDS § 169.14 Deposit and disbursement of consideration and damages. At the time of filing an application for right-of-way, the applicant must deposit with the Secretary the...

  9. 25 CFR 169.14 - Deposit and disbursement of consideration and damages.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .... 169.14 Section 169.14 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER RIGHTS-OF-WAY OVER INDIAN LANDS § 169.14 Deposit and disbursement of consideration and damages. At the time of filing an application for right-of-way, the applicant must deposit with the Secretary the...

  10. 25 CFR 169.14 - Deposit and disbursement of consideration and damages.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... 169.14 Section 169.14 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER RIGHTS-OF-WAY OVER INDIAN LANDS § 169.14 Deposit and disbursement of consideration and damages. At the time of filing an application for right-of-way, the applicant must deposit with the Secretary the...

  11. 25 CFR 169.14 - Deposit and disbursement of consideration and damages.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... 169.14 Section 169.14 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER RIGHTS-OF-WAY OVER INDIAN LANDS § 169.14 Deposit and disbursement of consideration and damages. At the time of filing an application for right-of-way, the applicant must deposit with the Secretary the...

  12. ESTIMATES OF CLOUD WATER DEPOSITION AT MOUNTAIN DEPOSITION AT MOUNTAIN ACID DEPOSITION PROGRAM SITES IN THE APPALACHIAN MOUNTAINS

    EPA Science Inventory

    Cloud water deposition was estimated at three high elevation sites in the Appalachian Mountains of the eastern United States (Whiteface Mountain, NY, Whitetop Mountain, VA, and Clingrnan's Dome, TN) from 1994 through 1999 as part of the Mountain Acid Deposition Program (MADPro). ...

  13. Factors affecting response of surface waters to acidic deposition

    SciTech Connect

    Turner, R.S.; Johnson, D.W.; Elwood, J.W.; Van Winkle, W.; Clapp, R.B.; Reuss, J.O.

    1986-04-01

    Knowledge of watershed hydrology and of the biogeochemical reactions and elemental pools and fluxes occurring in watersheds can be used to classify the response of watersheds and surface waters to acidic deposition. A conceptual mosel is presented for classifying watersheds into those for which (1) surface water chemistry will change rapidly with deposition quality (direct response) (2) surface water chemistry will change only slowly over time (delayed response), and (3) surface water chemistry will not change significantly, even with continued acidic deposition (capacity-protected). Techniques and data available for classification of all watersheds in a region into these categories are discussed.

  14. EMISSION INVENTORY APPLICATIONS TO REGIONAL ACID DEPOSITION MODELING

    EPA Science Inventory

    A comprehensive Regional Acid Deposition Model (RADM) is being developed and a simpler fast-turn-around 'engineering' model(s) (EM) is being designed by the National Center for Atmospheric Research as part of the National Acid Precipitation Assessment Program (NAPAP). This paper ...

  15. ANTHROPOGENIC EMISSIONS INVOLVED IN ACIDIC DEPOSITION PROCESSES

    EPA Science Inventory

    The paper describes the methodology that was used to develop the 1985 National Acid Precipitation Assessment Program (NAPAP) Emissions Inventory, including quality control procedures. and summarizes the inventory contents. evelopment of the 1985 inventory required detailed invest...

  16. ACID PRECIPITATION IN NORTH AMERICA: 1984 ANNUAL DATA SUMMARY FROM ACID DEPOSITION SYSTEM DATA BASE

    EPA Science Inventory

    The report gives a summary of 1984 wet deposition precipitation chemistry data collected in North America and available in the Acid Deposition System (ADS) data base. North American wet deposition monitoring networks with data in ADS are NADP/NTN, CANSAP, APN, UAPSP, MAP3S/PCN, W...

  17. ACID PRECIPITATION IN NORTH AMERICA: 1983 ANNUAL DATA SUMMARY FROM ACID DEPOSITION SYSTEM DATA BASE

    EPA Science Inventory

    The report gives a summary of 1983 wet deposition precipitation chemistry data collected in North America and available in the Acid Deposition System (ADS) data base. North American wet deposition monitoring networks with data in ADS are NADP/NTN, CANSAP, APN, UAPSP, MAP3S/PCN, W...

  18. Effects of Lipoic Acid on Acrylamide Induced Testicular Damage

    PubMed Central

    Lebda, Mohamed; Gad, Shereen; Gaafar, Hossam

    2014-01-01

    Introduction: Acrylamide is very toxic to various organs and associated with significant increase of oxidative stress and depletion of antioxidants. Alpha-lipoic acid enhances cellular antioxidant defense capacity, thereby protecting cells from oxidative stress. Aim of the study: This study aimed to evaluate the protective role of alpha-lipoic acid on the oxidative damage induced by acrylamide in testicular and epididymal tissues. Material and methods: Forty adult male rats were divided into four groups (10 rats each). Control group; acrylamide treated group administered acrylamide 0.05% (w/v) in drinking water for 21 days; alpha-lipoic acid group received basal diet supplemented with 1% alpha-lipoic acid and forth group was exposed to acrylamide and treated with alpha-lipoic acid at the same doses and treatment regimen mentioned before. Results: The administration of acrylamide resulted in significant elevation in testicular and epididymal malondialdehyde level (MDA) and significant reduction in the level of reduced glutathione (GSH) and the activities of glutathione-S-transferase (GST), glutathione peroxidase (GPX) and glutathione reductase (GR). Also, acrylamide significantly reduced serum total testosterone and progesterone but increased estradiol (E2) levels. Treatment with alpha-lipoic acid prior to acrylamide induced protective effects and attenuated these biochemical changes. Conclusion: Alpha-lipoic acid has been shown to possess antioxidant properties offering promising efficacy against oxidative stress induced by acrylamide administration. PMID:25126019

  19. A mechanistic study of phosphinocarboxylic acid for boiler deposit control

    SciTech Connect

    Chang, K.Y.; Patel, S.

    1995-11-01

    A laboratory study has been carried out to identify the key properties of phosphinocarboxylic acid polymers to control boiler water deposits. These multifunctional properties are its ability to: transport iron, disperse boiler water sludge that contains iron oxide, silica and calcium phosphate and dissolution of deposits. The thermal and hydrolytic stability of the phosphinocarboxylic acid polymers was investigated in autoclave studies up to 1,500 psig. The post-autoclave samples were analyzed by Nuclear Magnetic Resonance Spectroscopy and Aqueous Gel Permeation Chromatography to ascertain the polymer integrity. In addition performance tests were carried out for pre- and post-autoclave polymer samples. The performance testing clearly shows that phosphinocarboxylic acid polymers are effective in maintaining deposit control in a boiler due to their inherent thermal stability.

  20. Studying post depositional damage on Acheulian bifaces using 3-D scanning.

    PubMed

    Grosman, Leore; Sharon, Gonen; Goldman-Neuman, Talia; Smikt, Oded; Smilansky, Uzy

    2011-04-01

    In this study, we explore post-depositional damage observed on Acheulian bifacial tools by comparing two assemblages: a collection of archaeological handaxes which shows pronounced damage marks associated with high energy water accumulation system, and an experimental assemblage that was rolled and battered in a controlled simulation experiment. Scanning the two assemblages with a precise 3-D optical scanner and subjecting the measured surfaces to the same mathematical analysis enabled the development of quantitative measures assessing and comparing the degree of damage observed on archaeological and experimental tools. The method presented here enables the definition of morphological patterns typically resulting from battering and different from intentional controlled knapping. The most important kinds of damage included the formation of deep, random 'notch-like' scars on the lateral edges and substantial degrees of damage to the tip of the tools, but minimal damage to the artifact's butt. Quantifying the degree of damage and its location and morphological characters allows us to present a method by which post depositional damage on archaeological tools can be measured. PMID:20304464

  1. Formation damage prevention through the control of paraffin and asphaltene deposition

    SciTech Connect

    Newberry, M.E.; Barker, K.M.

    1985-03-01

    Formation damage caused by the precipitation and deposition of paraffin or asphaltene particles has been a recurrent problem in the production of crude oil. A number of well established oilfield operations have been found to aggravate these organic deposition problems. Laboratory testing of crudes and chemical additives has led to a number of solutions to these problems. Case history information on testing, chemical application, and subsequent field results are presented.

  2. Phenolic acids as bioindicators of fly ash deposit revegetation.

    PubMed

    Djurdjević, L; Mitrović, M; Pavlović, P; Gajić, G; Kostić, O

    2006-05-01

    The floristic composition, the abundance, and the cover of pioneer plant species of spontaneously formed plant communities and the content of total phenolics and phenolic acids, as humus constituents, of an ash deposit after 7 years of recultivation were studied. The restoration of both the soil and the vegetation on the ash deposits of the "Nikola Tesla-A" thermoelectric power plant in Obrenovac (Serbia) is an extremely slow process. Unfavorable physical and chemical characteristics, the toxicity of fly ash, and extreme microclimatic conditions prevented the development of compact plant cover. The abundance and cover of plants increased from the central part of the deposit towards its edges (ranging from 1-80%). Festuca rubra L., Crepis setosa Hall., Erigeron canadensis L., Cirsium arvense (L.) Scop., Calamagrostis epigeios (L.) Roth., and Tamarix gallica L. were the most abundant species, thus giving the highest cover. Humus generated during the decomposition process of plant remains represents a completely new product absent in the ash as the starting material. The amount of total phenolics and phenolic acids (38.07-185.16 microg/g of total phenolics and 4.12-27.28 microg/g of phenolic acids) in fly ash increased from the center of the deposit towards its edges in correlation with the increase in plant abundance and cover. Ash samples contained high amounts of ferulic, vanillic, and p-coumaric acid, while the content of both p-hydroxybenzoic and syringic acid was relatively low. The presence of phenolic acids indicates the ongoing process of humus formation in the ash, in which the most abundant pioneer plants of spontaneously formed plant communities play the main role. Phenolic compounds can serve as reliable bioindicators in an assessment of the success of the recultivation process of thermoelectric power plants' ash deposits. PMID:16418890

  3. Phenolic acids as bioindicators of fly ash deposit revegetation

    SciTech Connect

    L. Djurdjevic; M. Mitrovic; P. Pavlovic; G. Gajic; O. Kostic

    2006-05-15

    The floristic composition, the abundance, and the cover of pioneer plant species of spontaneously formed plant communities and the content of total phenolics and phenolic acids, as humus constituents, of an ash deposit after 7 years of recultivation were studied. The restoration of both the soil and the vegetation on the ash deposits of the 'Nikola Tesla-A' thermoelectric power plant in Obrenovac (Serbia) is an extremely slow process. Unfavorable physical and chemical characteristics, the toxicity of fly ash, and extreme microclimatic conditions prevented the development of compact plant cover. The abundance and cover of plants increased from the central part of the deposit towards its edges. Festuca rubra L., Crepis setosa Hall., Erigeron canadensis L., Cirsium arvense (L.) Scop., Calamagrostis epigeios (L.) Roth., and Tamarix gallica L. were the most abundant species, thus giving the highest cover. Humus generated during the decomposition process of plant remains represents a completely new product absent in the ash as the starting material. The amount of total phenolics and phenolic acids in fly ash increased from the center of the deposit towards its edges in correlation with the increase in plant abundance and cover. The presence of phenolic acids indicates the ongoing process of humus formation in the ash, in which the most abundant pioneer plants of spontaneously formed plant communities play the main role. Phenolic compounds can serve as reliable bioindicators in an assessment of the success of the recultivation process of thermoelectric power plants' ash deposits.

  4. PARAMETRIC METHODOLOGIES OF CLOUD VERTICAL TRANSPORT FOR ACID DEPOSITION MODELS

    EPA Science Inventory

    A CUmulus VENTing (CUVENT) cloud module has been developed that calculates the vertical flux of mass from the boundary layer to the cloud layer by an ensemble of nonprecipitating subgrid-scale air mass clouds. This model will be integrated into the Regional Acid Deposition Model ...

  5. POLLUTANT SAMPLER FOR MEASUREMENTS OF ATMOSPHERIC ACIDIC DRY DEPOSITION

    EPA Science Inventory

    An acidic pollutant sampler for dry deposition monitoring has been designed and evaluated in laboratory and field studies. The system, which is modular and simple to operate, samples gaseous HNO3, NH3, SO2 and NO2 and particulate SO4(-2), NO3(1-) and NH4(1+) and is made of Teflon...

  6. 25 CFR 169.14 - Deposit and disbursement of consideration and damages.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ....14 Section 169.14 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER RIGHTS... of filing an application for right-of-way, the applicant must deposit with the Secretary the total estimated consideration and damages, which shall include consideration for the right-of-way,...

  7. A systematic approach for the prevention and treatment of formation damage caused by asphaltene deposition

    SciTech Connect

    Leontaritis, K.J.; Amaefule, J.O.; Charles, R.E. )

    1994-08-01

    Asphaltene plugging is a known cause of near-wellbore formation damage. Deposited asphaltenes can reduce effective hydrocarbon mobility by (1) blocking the pore throats; (2) adsorbing onto the rock, thereby altering the formation wettability from water-wet to oil-wet; and (3) increasing hydrocarbon viscosity by nucleating water-in-oil emulsions. Asphaltene flocculation and deposition can be avoided in some, but not all, cases. Some formation damage resulting from asphaltene plugging is permanent and hence must be prevented rather than treated. Prevention of asphaltene-induced formation damage should be started in the early stages of drilling and well completion, once the oil is known to be asphaltenic. This paper presents a systematic approach to successful diagnosis, prevention, and mitigation of asphaltene problems during recovery of asphaltenic oils. A mechanism of asphaltene flocculation and deposition is proposed and analyzed, and the previously defined concept of asphaltene deposition envelope is further refined. Diagnostic technology is presented that can test the compatibility of drilling and completion fluids with any asphaltenic oil. Important issues that need to be considered in the design of treatments for asphaltene removal are discussed. Finally, the paper presents a methodology for restoring unfavorable wettability changes caused by asphaltene deposition.

  8. Emissions involved in acidic deposition processes: Methodology and results

    SciTech Connect

    Placet, M.

    1990-01-01

    Data on the emissions involved in atmospheric acid-base chemistry are crucial to the assessment of acidic deposition and its effects. Sulfur dioxide (SO{sub 2}), nitrogen oxides (NO{sub x}), and volatile organic compounds (VOCs) are the primary chemical compounds involved in acidic deposition processes. In addition, other emission species -- e.g., ammonia, alkaline dust particles, hydrogen chloride, and hydrogen fluoride -- are involved in atmospheric acid-base chemistry, either by contributing acidic constituents or by neutralizing acidic species. Several emissions data bases have been developed under the auspices of the National Acid Precipitation Program (NAPAP). In addition to those developed by NAPAP, emissions data bases and emissions trends estimates also have been developed by organizations such as the Electric Power Research Institute (EPRI) and the U.S. Environmental Protection Agency (EPA). This paper briefly describes and compares the methods used in developing these emissions data bases and presents an overview of their emissions estimates. A more detailed discussion of these topics can be found in the State-of-Science Report on emissions recently released by NAPAP and in the references cited in that report. 14 refs., 4 figs., 1 tab.

  9. Electrophoretic deposition of tannic acid-polypyrrolidone films and composites.

    PubMed

    Luo, Dan; Zhang, Tianshi; Zhitomirsky, Igor

    2016-05-01

    Thin films of polyvinylpyrrolidone (PVP)-tannic acid (TA) complexes were prepared by a conceptually new strategy, based on electrophoretic deposition (EPD). Proof of concept investigations involved the analysis of the deposition yield, FTIR and UV-vis spectroscopy of the deposited material, and electron microscopy studies. The analysis of the deposition mechanism indicated that the limitations of the EPD in the deposition of small phenolic molecules, such as TA, and electrically neutral polymers, similar to PVP, containing hydrogen-accepting carbonyl groups, can be avoided. The remarkable adsorption properties of TA and film forming properties of the PVP-TA complexes allowed for the EPD of materials of different types, such as huntite mineral platelets and hydrotalcite clay particles, TiO2 and MnO2 oxide nanoparticles, multiwalled carbon nanotubes, TiN and Pd nanoparticles. Moreover, PVP-TA complexes were used for the co-deposition of different materials and formation of composite films. In another approach, TA was used as a capping agent for the hydrothermal synthesis of ZnO nanorods, which were then deposited by EPD using PVP-TA complexes. The fundamental adsorption and interaction mechanisms of TA involved chelation of metal atoms on particle surfaces with galloyl groups, π-π interactions and hydrogen bonding. The films prepared by EPD can be used for various applications, utilizing functional properties of TA, PVP, inorganic and organic materials of different types and their composites. PMID:26878711

  10. A novel enzyme-based acidizing system: Matrix acidizing and drilling fluid damage removal

    SciTech Connect

    Harris, R.E.; McKay, D.M.; Moses, V.

    1995-12-31

    A novel acidizing process is used to increase the permeability of carbonate rock cores in the laboratory and to remove drilling fluid damage from cores and wafers. Field results show the benefits of the technology as applied both to injector and producer wells.

  11. MOUNTAIN ACID DEPOSITION PROGRAM (MADPRO): CLOUD DEPOSITION TO THE APPALACHIAN MOUNTAINS, 1994 THROUGH 1999

    EPA Science Inventory

    The mountain Acid Deposition Program (MADPro) was initiated in 1993 as part of the research necessary to support the objectives of the Clean Air Status and Trends Network (CASTNet), which was created to address the requirements of the Clean Air Act Amendments (CAAA). The two ma...

  12. Relationship between iron deposits and tissue damage in the synovium: an ultrastructural study.

    PubMed Central

    Morris, C J; Blake, D R; Wainwright, A C; Steven, M M

    1986-01-01

    A detailed ultrastructural study was made of the synovial iron deposits in cases of haemophilic synovitis (HS), pigmented villonodular synovitis (PVNS), rheumatoid arthritis (RA), osteoarthritis (OA), seronegative inflammatory arthritis (SNA), and in controls, to investigate the relationship between iron deposits and tissue damage. Iron was seen by electron microscopy in about 75% of synovial lining cells in HS and PVNS but only in about 25% of synovial cells from cases of RA and SNA. In cases of OA and in controls iron deposits were scarce. The iron was usually deposited within pleomorphic siderosomes and in HS was most common in type A synovial cells. In contrast, deposits in all other cases were more common in type B cells, which were frequently the predominant cell type, and siderosomes were smaller, more homogeneous, and were more common in deeper synovial tissue. Considerable tissue damage was noted in the vicinity of iron rich siderosomes in synovial A cells from cases of HS, but such deposits in B cells in the synovium from the other cases had relatively little effect. We discuss the possibility that such differences directly reflect the differing functions of type A and B synovial cells, and particularly their relative ability to produce metabolically active oxygen metabolites with tissue destructive potential in the presence of iron. Images PMID:3954454

  13. Role of acid rain in atmospheric deposition. Final report

    SciTech Connect

    Winchester, J.W.

    1990-12-31

    A study was conducted to assess the potential importance of atmospheric nitrate deposition for a north Florida estuary. A comparison, based on statistical analysis of fluxes of ten dissolved constituents of rain water and river water, has been carried out for the watershed of the Apalachicola River, utilizing weekly rain water chemical data from the National Acid Deposition Program (NADP) for five sites within the watershed area, monitored from 1978-84 until late 1989, and less frequent river water chemical data from the U.S. Geological Survey for one site at Chattahoochee, Florida, monitored from 1965 until late 1989. Similar statistical analysis was performed on monitoring data for the Sopchoppy and Ochlockonee Rivers of north Florida. Atmospheric deposition to the watershed appears to be sufficient to account for essentially all the dissolved nitrate and ammonium and total organic nitrogen flow in the three rivers. However, after deposition most of the nitrate may be transformed to other chemical forms during the flow of the rivers toward their estuaries. In an additional statistical analysis of rain water monitoring data from the eight state southeastern USA region, it was found that both meteorological conditions and transport from pollution sources appear to control deposition fluxes of nitrate and sulfate acid air pollutants.

  14. Estimates of cloud water deposition at Mountain Acid Deposition Program sites in the Appalachian Mountains.

    PubMed

    Baumgardner, Ralph E; Isil, Selma S; Lavery, Thomas F; Rogers, Christopher M; Mohnen, Volker A

    2003-03-01

    Cloud water deposition was estimated at three high-elevation sites in the Appalachian Mountains of the eastern United States (Whiteface Mountain, NY; Whitetop Mountain, VA; and Clingman's Dome, TN) from 1994 through 1999 as part of the Mountain Acid Deposition Program (MADPro). This paper provides a summary of cloud water chemistry, cloud liquid water content, cloud frequency, estimates of cloud water deposition of sulfur and nitrogen species, and estimates of total deposition of sulfur and nitrogen at these sites. Other cloud studies in the Appalachians and their comparison to MADPro are also summarized. Whiteface Mountain exhibited the lowest mean and median concentrations of sulfur and nitrogen ions in cloud water, while Clingman's Dome exhibited the highest mean and median concentrations. This geographic gradient is partly an effect of the different meteorological conditions experienced at northern versus southern sites in addition to the difference in pollution content of air masses reaching the sites. All sites measured seasonal cloud water deposition rates of SO4(2-) greater than 50 kg/ha and NO3(-) rates of greater than 25 kg/ha. These high-elevation sites experienced additional deposition loading of SO4(2-) and NO3(-) on the order of 6-20 times greater compared with lower elevation Clean Air Status and Trends Network (CASTNet) sites. Approximately 80-90% of this extra loading is from cloud deposition. PMID:12661689

  15. Simulated seasonal variations in wet acid depositions over East Asia.

    PubMed

    Ge, Cui; Zhang, Meigen; Zhu, Lingyun; Han, Xiao; Wang, Jun

    2011-11-01

    The air quality modeling system Regional Atmospheric Modeling System-Community Multi-scale Air Quality (RAMS-CMAQ) was applied to analyze temporospatial variations in wet acid deposition over East Asia in 2005, and model results obtained on a monthly basis were evaluated against extensive observations, including precipitation amounts at 704 stations and SO4(2-), NO3-, and NH4+ concentrations in the atmosphere and rainwater at 18 EANET (the Acid Deposition Monitoring Network in East Asia) stations. The comparison shows that the modeling system can reasonably reproduce seasonal precipitation patterns, especially the extensive area of dry conditions in northeast China and north China and the major precipitation zones. For ambient concentrations and wet depositions, the simulated results are in reasonable agreement (within a factor of 2) with observations in most cases, and the major observed features are mostly well reproduced. The analysis of modeled wet deposition distributions indicates that East Asia experiences noticeable variations in its wet deposition patterns throughout the year. In winter, southern China and the coastal areas of the Japan Sea report higher S04(2-) and NO3- wet depositions. In spring, elevated SO4(2-) and NO3-wet depositions are found in northeastern China, southern China, and around the Yangtze River. In summer, a remarkable rise in precipitation in northeastern China, the valleys of the Huaihe and Yangtze rivers, Korea, and Japan leads to a noticeable increase in SO4(2-) and NO3- wet depositions, whereas in autumn, higher SO4(2-) and NO3-wet depositions are found around Sichuan Province. Meanwhile, due to the high emission of SO2, high wet depositions of SO4(2-) are found throughout the entire year in the area surrounding Sichuan Province. There is a tendency toward decreasing NO3- concentrations in rainwater from China through Korea to Japan in both observed and simulated results, which is a consequence of the influence of the continental

  16. Studies of acid deposition and its effects in two small catchments in Hunan, China

    NASA Astrophysics Data System (ADS)

    Xue, Nandong; Seip, Hans Martin; Liao, Bohan; Vogt, Rolf D.

    Acid deposition and its effects were studied by analysing the chemistry in precipitation, stream water, soil water and soils in two catchments in Hunan. One site, Linkesuo (denoted LKS), is on the outskirts of Changsha, the provincial capital of Hunan, the other (Bailutang, denoted BLT) on the outskirts of Chenzhou in southern Hunan. Volume-weighted average pH values and sulphate concentrations in wet deposition were 4.58 (BLT) and 4.90 (LKS) and 174 μmolc L-1 and 152 μmolc L-1, respectively. Wet deposition of sulphate has been estimated as 4.3 gS m-2yr-1 and 3.4 gS m-2yr-1 at BLT and LKS, respectively. Estimates of the corresponding total depositions (dry + wet) are 6.1 gS m-2yr-1 and 5.3 gS m-2yr-1. In precipitation and throughfall, sulphate was the major anion and calcium the major cation. In stream and soil water, nitrate was slightly higher than sulphate on an equivalent basis and magnesium (Mg) not much lower than calcium (Ca). Important soil properties, such as soil pH, soil organic matter (SOM) content, exchangeable acidic cations, exchangeable base cations, effective cation exchange capacity (CECe), base saturation (BS), and aluminium (Al) and iron (Fe) pools, were determined for five forest soil profiles (consisting of four horizons) in each of the two catchments. The soils in BLT are generally more acid, have lower BS and higher Al and Fe pools than the LKS soils. The Al- and Fe-pools were generally higher in the topsoils (i.e. the O and A horizons) than in deeper soils (i.e. E and B horizons) especially at the most acidic site (BLT). There are significant correlations between Fe-pools and the corresponding Al-pools in both catchments except between the amorphous Feox and Alox. Considering the long-term high deposition of sulphate, there is a risk of future ecological damage due to acidification, especially in the BLT catchment, although vegetation damage has yet to be observed in the catchments. This condition appears to be representative of a large

  17. Monte Carlo Techniques for Calculations of Charge Deposition and Displacement Damage from Protons in Visible and Infrared Sensor Arrays

    NASA Technical Reports Server (NTRS)

    Marshall, Paul; Reed, Robert; Fodness, Bryan; Jordan, Tom; Pickel, Jim; Xapsos, Michael; Burke, Ed

    2004-01-01

    This slide presentation examines motivation for Monte Carlo methods, charge deposition in sensor arrays, displacement damage calculations, and future work. The discussion of charge deposition sensor arrays includes Si active pixel sensor APS arrays and LWIR HgCdTe FPAs. The discussion of displacement damage calculations includes nonionizing energy loss (NIEL), HgCdTe NIEL calculation results including variance, and implications for damage in HgCdTe detector arrays.

  18. Low-damage high-throughput grazing-angle sputter deposition on graphene

    SciTech Connect

    Chen, C.-T.; Gajek, M.; Raoux, S.; Casu, E. A.

    2013-07-15

    Despite the prevalence of sputter deposition in the microelectronics industry, it has seen very limited applications for graphene electronics. In this letter, we report systematic investigation of the sputtering induced damages in graphene and identify the energetic sputtering gas neutrals as the primary cause of graphene disorder. We further demonstrate a grazing-incidence sputtering configuration that strongly suppresses fast neutral bombardment and retains graphene structure integrity, creating considerably lower damage than electron-beam evaporation. Such sputtering technique yields fully covered, smooth thin dielectric films, highlighting its potential for contact metals, gate oxides, and tunnel barriers fabrication in graphene device applications.

  19. RAINS-ASIA: An assessment model for acid deposition in Asia

    SciTech Connect

    Downing, R.J.; Ramankutty, R.; Shah, J.J.

    1997-08-31

    Asia`s rapid economic growth has fueled a growing appetite for commercial energy, which is satisfied by fossil fuels that emit pollutants. These pollutants are oxidized and transported into the atmosphere, creating acidic depositions known as acid rain that can damage foliage, soils, and surface waters. At current energy consumption growth rates, by the year 2000 sulfur dioxide emissions from Asia will surpass the emissions of North America and Europe combined. RAINS-ASIA is an assessment tool developed by the World Bank, the Asian Development Bank, and donors to study the implications of alternative energy development strategies for air pollution and acid rain and to help identify cost-effective abatement methods. This report provides an overview of the model and some results of analyses that have been conducted as part of the RAINS-ASIA program.

  20. Protective Effect of Folic Acid on Oxidative DNA Damage

    PubMed Central

    Guo, Xiaojuan; Cui, Huan; Zhang, Haiyang; Guan, Xiaoju; Zhang, Zheng; Jia, Chaonan; Wu, Jia; Yang, Hui; Qiu, Wenting; Zhang, Chuanwu; Yang, Zuopeng; Chen, Zhu; Mao, Guangyun

    2015-01-01

    Abstract Although previous reports have linked DNA damage with both transmissions across generations as well as our own survival, it is unknown how to reverse the lesion. Based on the data from a Randomized, Double-blind, Placebo Controlled Clinical Trial, this study aimed to assess the efficacy of folic acid supplementation (FAS) on DNA oxidative damage reversal. In this randomized clinical trial (RCT), a total of 450 participants were enrolled and randomly assigned to 3 groups to receive folic acid (FA) 0.4 mg/day (low-FA), 0.8 mg/day (high-FA), or placebo (control) for 8 weeks. The urinary 8-hydroxy-2’-deoxyguanosine (8-OHdG) and creatinine (Cr) concentration at pre- and post-FAS were measured with modified enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC), respectively. A multivariate general linear model was applied to assess the individual effects of FAS and the joint effects between FAS and hypercholesterolemia on oxidative DNA damage improvement. This clinical trial was registered with ClinicalTrials.gov, number NCT02235948. Of the 438 subjects that received FA fortification or placebo, the median (first quartile, third quartile) of urinary 8-OHdG/Cr for placebo, low-FA, and high-FA groups were 58.19 (43.90, 82.26), 53.51 (38.97, 72.74), 54.73 (39.58, 76.63) ng/mg at baseline and 57.77 (44.35, 81.33), 51.73 (38.20, 71.30), and 50.65 (37.64, 76.17) ng/mg at the 56th day, respectively. A significant decrease of urinary 8-OHdG was observed after 56 days FA fortification (P < 0.001). Compared with the placebo, after adjusting for some potential confounding factors, including the baseline urinary 8-OHdG/Cr, the urinary 8-OHdG/Cr concentration significantly decreased after 56 days FAS [β (95% confidence interval) = −0.88 (−1.62, −0.14) and P = 0.020 for low-FA; and β (95% confidence interval) = −2.68 (−3.42, −1.94) and P < 0.001 for high-FA] in a dose-response fashion (Ptrend

  1. ACIDIC DEPOSITION IN THE NORTHEASTERN U.S.: SOURCES AND INPUTS, ECOSYSTEM EFFECTS, AND MANAGEMENT STRATEGIES

    EPA Science Inventory

    Acidic deposition results from the emissions of air pollutants. Effects of acidic deposition in the northeastern US include the acidification of soil and water, causing stresses to terrestrial and aquatic biota.

  2. Impact of Propionic Acid on Liver Damage in Rats

    PubMed Central

    Al- Daihan, Sooad; Shafi Bhat, Ramesa

    2015-01-01

    Propionic acid (PA) is a short chain fatty acid, a common food preservative and metabolic end product of enteric bacteria in the gut. The present study was undertaken to investigate the effect of PA on liver injury in male rats. Male western albino rats were divided into two groups. The first group served as normal control, the second was treated with PA. The activities of serum hepatospecific markers such as aspartate transaminase, alanine transaminase, and alkaline phosphatase were estimated. Antioxidant status in liver tissues was estimated by determining the level of lipid peroxidation and activities of enzymatic and non-enzymatic antioxidants. Sodium and potassium levels were also measured in liver tissue. PA treatment caused significant changes in all hepatospecific markers. Biochemical analysis of liver homogenates from PA-treated rats showed an increase in oxidative stress markers like lipid peroxidation and lactate dehydrogenase, coupled with a decrease in glutathione, vitamin C and glutathione S- transferase. However, PA exposure caused no change in sodium and potassium levels in liver tissue. Our study demonstrated that PA persuade hepatic damage in rats. PMID:26629488

  3. Assessment of the economic magnitude of environmental damage from acid precipitation in the Adirondacks

    SciTech Connect

    Menz, F.C.; Mullen, J.K.

    1983-05-01

    This research represents one of a few initial attempts to quantify economic damages resulting from increased acidification of lakes and ponds ostensibly due to acidic deposition. The focus of this research is the loss in economic welfare resulting from diminished recreational angling opportunities within the Adirondack fishery. An amended travel-cost model was applied to a survey of licensed anglers in New York State to determine the economic value of the fishery prior to the general acknowledgement of widespread acidification damages. Data pertaining to those water bodies that have become acidified were used together with the parameters of the empirical model to generate the change in visitation and economic value resulting from increased acidification. Annual losses in economic value due to the acidification-related reduction in recreational angling opportunities were estimated to be in the range of $1.6 to 3.2 million. These estimates should be interpreted as a lower bound of the actual social losses incurred annually from acidification damages to this freshwater ecosystem. 6 references.

  4. Mathematical modeling of acid deposition due to radiation fog

    SciTech Connect

    Pandis, S.N.; Seinfeld, J.H. )

    1989-09-20

    A Lagrangian model has been developed to study acidic deposition due to radiation fog. The model couples submodels describing the development and dissipation of radiation fog, the gas-phase chemistry and transfer, and the aqueous-phase chemistry. The model is applied to a radiation fog episode in Bakersfield in the San Joaquin Valley of California over the period January 4--5 1985. Model predictions for temperature profile, fog development, liquid water content, gas-phase concentrations of SO{sub 2}, HNO{sub 3}, and NH{sub 3}, {ital p}H, aqueous-phase concentrations of OS{sup 2{minus}}{sub 4}, NH{sup +}{sub 4}, and NO{sup {minus}}{sub 3}, and finally deposition rates of the above ions are compared with the observed values. The deposition rates of the major ions are predicted to increase significantly during the fog episode, the most notable being the increase of sulfate deposition. Pathways for sulfate production that are of secondary importance in a cloud environment may become signficant in a fog. Expressing the mean droplet settling velocity as a function of liquid water content is found to be quite influential in the model's predictions. {copyright} American Geophysical Union 1989

  5. Acid Deposition From Stratospheric Geoengineering With Sulfate Aerosols

    NASA Astrophysics Data System (ADS)

    Kravitz, B.; Robock, A.; Oman, L.; Stenchikov, G.

    2008-12-01

    We used a general circulation model of the Earth's climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide [Robock et al., 2008] and analyzed the resulting deposition of sulfate. When sulfur is injected into the tropical or Arctic stratosphere, the main additional surface deposition occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions, and there are some larger local increases, specifically in Northern Canada and the Western Pacific Ocean. We used critical load studies to determine the effects of this increase in acid deposition on terrestrial ecosystems. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, the additional surface sulfate deposition is not enough to negatively impact most ecosystems. Robock, Alan, Luke Oman, and Georgiy Stenchikov (2008), Regional climate responses to geoengineering with tropical and Arctic SO2 injections. J. Geophys. Res., 113, D16101, doi:10.1029/2008JD010050.

  6. Mitigation of acid deposition: Liming of surface waters. Final report

    SciTech Connect

    Bartoshesky, J.; Price, R.; DeMuro, J.

    1989-05-01

    In recent years acid deposition has become a serious concern internationally. Scientific literature has documented the acidification of numerous lakes and streams in North America and Scandinavia resulting in the depletion or total loss of fisheries and other aquatic biota. Liming represents the only common corrective practice aimed specifically at remediating an affected acid receptor. This report reviews a range of liming technologies and liming materials, as well as the effect of surface-water liming on water quality and aquatic biota. As background to the liming discussion, the hydrologic cycle and the factors that make surface waters sensitive to acid deposition are also discussed. Finally, a brief review of some of the liming projects that have been conducted, or are currently in operation is presented, giving special emphasis to mitigation efforts in Maryland. Liming has been effectively used to counteract surface-water acidification in parts of Scandinavia, Canada, and the U.S. To date, liming has generally been shown to improve physical and chemical conditions and enhance the biological recovery of aquatic ecosystems affected by acidification.

  7. Polyglycolic acid microneedles modified with inkjet-deposited antifungal coatings.

    PubMed

    Boehm, Ryan D; Daniels, Justin; Stafslien, Shane; Nasir, Adnan; Lefebvre, Joe; Narayan, Roger J

    2015-01-01

    In this study, the authors examined use of piezoelectric inkjet printing to apply an antifungal agent, voriconazole, to the surfaces of biodegradable polyglycolic acid microneedles. Polyglycolic acid microneedles with sharp tips (average tip radius = 25 ± 3 μm) were prepared using a combination of injection molding and drawing lithography. The elastic modulus (9.9 ± 0.3 GPa) and hardness (588.2 ± 33.8 MPa) values of the polyglycolic acid material were determined using nanoindentation and were found to be suitable for use in transdermal drug delivery devices. Voriconazole was deposited onto the polyglycolic acid microneedles by means of piezoelectric inkjet printing. It should be noted that voriconazole has poor solubility in water; however, it is readily soluble in many organic solvents. Optical imaging, scanning electron microscopy, energy dispersive x-ray spectrometry, and Fourier transform infrared spectroscopy were utilized to examine the microneedle geometries and inkjet-deposited surface coatings. Furthermore, an in vitro agar plating study was performed on the unmodified, vehicle-modified, and voriconazole-modified microneedles. Unlike the unmodified and vehicle-modified microneedles, the voriconazole-modified microneedles showed antifungal activity against Candida albicans. The unmodified, vehicle-modified, and voriconazole-modified microneedles did not show activity against Escherichia coli, Pseudomonas aeruginosa, or Staphylococcus aureus. The results indicate that piezoelectric inkjet printing may be useful for loading transdermal drug delivery devices such as polyglycolic acid microneedles with antifungal pharmacologic agents and other pharmacologic agents with poor solubility in aqueous solutions. PMID:25732934

  8. Ascorbic acid (AA) metabolism in protection against radiation damage

    SciTech Connect

    Rose, R.C.; Koch, M.J.

    1986-03-05

    The possibility is considered that AA protects tissues against radiation damage by scavenging free radicals that result from radiolysis of water. A physiologic buffer (pH 6.7) was incubated with /sup 14/C-AA and 1 mM thiourea (to slow spontaneous oxidation of AA). Aliquots were assayed by HPLC and scintillation spectrometry to identify the /sup 14/C-label. Samples exposed to Cobalt-60 radiation had a half time of AA decay of < 3 minutes compared with nonirradiated samples (t/sub 1/2/ > 30 minutes) indicating that AA scavenges radiation-induced free radicals and forms the ascorbate free radical (AFR). Pairs of /sup 14/C-AFR disproportionate, with the net effect of /sup 14/C-dehydroascorbic acid formation from /sup 14/C-AA. Having established that AFR result from ionizing radiation in an aqueous solution, the possibility was evaluated that a tissue factor reduces AFR. Cortical tissue from the kidneys of male rats was minced, homogenized in buffer and centrifuged at 8000 xg. The supernatant was found to slow the rate of radiation-induced AA degradation by > 90% when incubated at 23/sup 0/C in the presence of 15 ..mu..M /sup 14/C-AA. Samples of supernatant maintained at 100/sup 0/C for 10 minutes or precipitated with 5% PCA did not prevent radiation-induced AA degradation. AA may have a specific role in scavenging free radicals generated by ionizing radiation and thereby protect body tissues.

  9. Mechanical damage to Escherichia coli cells in a model of amino-acid crystal fermentation.

    PubMed

    Okutani, Satoshi; Iwai, Takayoshi; Iwatani, Shintaro; Kondo, Kazuya; Osumi, Tsuyoshi; Tsujimoto, Nobuharu; Matsuno, Kiyoshi

    2012-04-01

    We investigated the mechanical damage to the Escherichia coli cell caused by polyvinyl chloride particles as a model of amino-acid crystal fermentation. Our results indicated that the glucose-consumption rate and the intracellular ATP concentration temporarily increased by the mechanical damage, and decreased after considerable damage had occurred on cell membrane. PMID:22153714

  10. Acid deposition in aquatic ecosystems: Setting limits empirically

    NASA Astrophysics Data System (ADS)

    Newcombe, Charles P.

    1985-07-01

    The problem of acid deposition and its harmful effects on aquatic ecosystems has created a new branch of science that is called upon to provide the knowledge on which legislative controls can be based. However, because of the nature of existing legislation, which requires evidence of cause and effect between industrial emissions and pollution, and because of science's inability to provide this information over the short term, considerable controversy has arisen about whether sufficient information exists to warrant control measures at this time. Among those who advocate controls, there is genuine divergence of opinion about how stringent the controls must be to achieve any desired level of protection. The controversy has led to an impasse between the scientific and political participants, which is reflected in the slow pace of progress toward an effective management strategy. Resolution of the impasse, at least in the short term, may demand that science and politics rely on empirical models rather than explanatory ones. The empirical model, which is the major proposal in this article, integrates all of the major variables and many of the minor ones, and constructs a three-dimensionally curved surface capable of representing the status of any waterbody subjected to the effects of acid deposition. When suitably calibrated—a process involving the integration of knowledge and data from aquatic biology, geochemistry, meteorology, and limnology—it can be used to depict limits to the rate of acid deposition required for any level of environmental protection. Because it can generate a pictorial display of the effects of management decisions and legislative controls, the model might serve as a basis for enhancing the quality of communication among all the scientific and political participants and help to resolve many of their controversies.

  11. PLASMID DNA DAMAGE CAUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    EPA Science Inventory

    PLASMID DNA DAMAGE CAOUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    ABSTRACT

    Both dimethylarsinic acid (DMA(V)) and dimethylarsinous acid (DMA(III)) release iron from human liver ferritin (HLF) with or without the presence of ascorbic acid. ...

  12. Hepatic Primary and Secondary Cholesterol Deposition and Damage in Niemann-Pick Disease.

    PubMed

    Bosch, Marta; Fajardo, Alba; Alcalá-Vida, Rafael; Fernández-Vidal, Andrea; Tebar, Francesc; Enrich, Carlos; Cardellach, Francesc; Pérez-Navarro, Esther; Pol, Albert

    2016-03-01

    Niemann-Pick C disease is a neurovisceral disorder caused by mutations in the NPC gene that result in systemic accumulation of intracellular cholesterol. Although neurodegeneration defines the disease's severity, in most patients it is preceded by hepatic complications such as cholestatic jaundice or hepatomegaly. To analyze the contribution of the hepatic disease in Niemann-Pick C disease progression and to evaluate the degree of primary and secondary hepatic damage, we generated a transgenic mouse with liver-selective expression of NPC1 from embryonic stages. Hepatic NPC1 re-expression did not ameliorate the onset and progression of neurodegeneration of the NPC1-null animal. However, the mice showed reduced hepatomegalia and dramatic, although not complete, reduction of hepatic cholesterol and serum bile salts, bilirubin, and transaminase levels. Therefore, hepatic primary and secondary cholesterol deposition and damage occur simultaneously during Niemann-Pick C disease progression. PMID:26784526

  13. Ultrasonic removal of organic deposits and polymer-induced formation damage

    SciTech Connect

    Roberts, P.M.; Venkitaraman, A.; Sharma, M.M.

    2000-03-01

    Experiments were conducted to investigate ultrasonic energy for reducing near-wellbore formation damage caused by organic deposits and polymers. It is shown that mechanical agitation provided by the acoustic waves re-suspends the paraffin and restores the effective permeability of the core to its undamaged condition. The depth of treatment is approximately 12 to 15 cm. This suggests that an acoustic source with or without solvents may provide an effective method of removing paraffins from the wellbore and the near-wellbore region. Ultrasonics was not as effective at restoring permeability damage caused by polymers. Results demonstrate that ultrasonic cleaning may be a viable method for cleaning the near-wellbore region when paraffin precipitation is a problem. The method would be particularly effective at treating long sections of pay where chemical methods may be too expensive.

  14. Distribution and effects of acidic deposition on wildlife and ecosystems

    USGS Publications Warehouse

    Stromborg, K.L.; Longcore, J.R.

    1987-01-01

    Acidic deposition occurs over most of the United States and the deposition patterns and theoretical vulnerabilities of aquatic ecosystems to chemical changes can be delineated, but few data exist on concomitant biological effects. Hypothetical direct effects are limited primarily to toxicity of various heavy metals mobilized at reduced pH. Results of studies in Scandinavia suggest that aluminum interferes with avian reproduction near acidified lakes. Some amphibian populations located on acid-vulnerable substrates may be adversely affected by reduced pH in the vernal pools used for egg laying and larval growth. Indirect effects on populations are difficult to detect because few historical data exist for wildlife populations and trophic relationships in vulnerable areas. Current research in the U.S.A. focuses on measuring habitat characteristics, food availability, and avian use of vulnerable wetland habitats. Results of Scandinavian studies suggest that some species of waterfowl may prefer acidified, I fish-free habitats because invertebrates essential for meeting nutritional requirements are more easily obtained in the absence of competition from fish. However, avian species dependent on fish would be absent from these habitats. Alteration of either the vegetative structure or primary productivity of wetlands might indirectly affect avian populations by causing decreased invertebrate productivity and consequent food limitations for birds.

  15. Acid fog deposition and the declining forest in Tanzawa mountains, Japan.

    NASA Astrophysics Data System (ADS)

    Igawa, M.; Shigihara, A.; Goto, S.; Nanzai, B.

    2010-07-01

    Since 1988, we have investigated fog chemistry in Mt. Oyama, Tanzawa mountains, Japan, and acid fog has been frequently observed there. We have observed fog on Mt. Oyama by using a night view video camera placed at the base of the mountain, by using a visibility meter at the top of the mountain, and by an active fog sampler at the mountainside. We have reported the fog frequency at the top of Mt. Oyama to be 46% measured by the video camera, but it was overestimated. The visibility measured at the top of the mountain is the most reliable index, and the top of the mountain is covered with fog for about 30%. The frequency of about 15% was added for the case of the visibility of a few km when it was measured by a night view video camera placed at the base of the mountain (8.5 km far from the top). Fog-water deposition increases with the increasing altitude to be much larger than the rain-water deposition. The factors affecting on the occult precipitation intensity were investigated by the simultaneous measurement of the rainfall intensity under a canopy, the wind speed and direction, and the visibility at the top of the mountain. Air pollution has been improved recently in Japan, but acid fog is not improved and has been affecting the leaves of the trees. In Tanzawa mountains, many fir trees and beech trees are declining, while cedar trees show no decline symptoms. We have investigated the effect of acid fog on the trees of these species by exposing simulated acid fog on the seedlings of the species. Seedlings of fir and beech are much damaged by the long term exposure of pH 3 fog, while cedar seedlings are not affected by the acid fog. By the exposure of simulated acid fog, the epicuticle wax is eroded at first, then the cross linking polycation between sugar chains of cell wall is ion-exchanged with proton and the cell wall is swollen, and the membrane calcium is desorbed from the membrane, which lowers the tolerance of the trees to the climate change. Fir and beech

  16. COMPREHENSIVE EXPERIMENTAL DESIGN PLAN TO RELATE POLLUTANT SOURCES TO ACIDIC DEPOSITION

    EPA Science Inventory

    Because verifiable numerical models that incorporate all processes determining the dispersion, transformations, and deposition of emitted pollutants associated with acidic deposition from the atmosphere are only now under development, it was deemed worthwhile to determine whether...

  17. Effects of some components of acid-mine drainage and acid deposition on the spermatozoa of longear sunfish, Lepomis megalotis

    SciTech Connect

    Pearson, B.J.

    1983-01-01

    The effects of low pH and the metals aluminum, zinc, and cadmium, components of acid-mine effluents and acid deposition, on spermatozoa of longear sunfish, Lepomis megalotis, were investigated. Sperm were exposed to solutions of 400 ppm aluminum chloride, 50 ppm zinc chloride, 2 ppm cadmium chloride, separately and in combination, at pH values of 6.9, 4.8, and 3.8. Sperm were additionally exposed to test solutions in which the metal salt concentration was reduced by one-half and observed for changes in motility and in the ability to exclude stain. All test solutions at a low pH were deleterious, the greatest damage occurring in solutions of a combination of all 3 metal chlorides and of aluminum chloride separately. Motility tests showed that both full and reduced metal concentrations had significant effects on motility. Staining tests were supportive of motility test results and indicated that in most cases shorter exposure times did not significantly improve survival rates. It was generally found that a decrease in pH increased the effects of each metal separately and when combined. Aluminum, zinc, and cadmium chlorides appeared to act antagonistically when tested in combination. It was concluded that the components of acid waters which were tested have deleterious effects on longer spermatozoa, reducing their viability and thereby reducing reproductive success of the species.

  18. USING THE REGIONAL ACID DEPOSITION MODEL TO DETERMINE THE NITROGEN DEPOSITION AIRSHED OF THE CHESAPEAKE BAY WATERSHED

    EPA Science Inventory

    The Regional Acid Deposition Model, RADM, an advanced Eulerian model, is used to develop an estimate of the primary airshed of nitrogen oxide (NOx) emissions that is contributing nitrogen deposition to the Chesapeake Bay watershed. rief description of RADM together with a summary...

  19. Acidic deposition, cation mobilization, and biochemical indicators of stress in healthy red spruce

    USGS Publications Warehouse

    Shortle, W.C.; Smith, K.T.; Minocha, R.; Lawrence, G.B.; David, M.B.

    1997-01-01

    Dendrochemical and biochemical markers link stress in apparently healthy red spruce trees (Picea rubens) to acidic deposition. Acidic deposition to spruce forests of the northeastern USA increased sharply during the 1960s. Previous reports related visible damage of trees at high elevations to root and soil processes. In this report, dendrochemical and foliar biochemical markers indicate perturbations in biological processes in healthy red spruce trees across the northeastern USA. Previous research on the dendrochemistry of red spruce stemwood indicated that under uniform environmental conditions, stemwood concentrations of Ca and Mg decreased with increasing radial distance from the pith. For nine forest locations, frequency analysis shows that 28 and 52% of samples of red spruce stemwood formed in the 1960s are enriched in Ca and Mg, respectively, relative to wood formed prior to and after the 1960s. This enrichment in trees throughout the northeastern USA may be interpretable as a signal of increased availability of essential cations in forest soils. Such a temporary increase in the availability of Ca and Mg could be caused by cation mobilization, a consequence of increased acidic deposition. During cation mobilization, essential Ca and Mg as well as potentially harmful Al become more available for interaction with binding sites in the soil and absorbing roots. As conditions which favor cation mobilization continue, Ca and Mg can be leached or displaced from the soil. A measure of the interaction between Ca and Al is the Al/Ca binding ratio (molar charge ratio of exchangeable Al to exchangeable Ca). As the Al/Ca binding ratio in the root zone increased from 0.3 to 1.9, the foliar concentration of the biochemical stress marker putrescine also increased from 45 to 145 nm g-1. The correlation of the putrescine concentration to the Al/Ca binding ratio (adj. r2 = 0.68, P < 0.027) suggests that foliar stress may be linked to soil chemistry.

  20. ACID PRECIPITATION IN NORTH AMERICA: 1985 ANNUAL AND SEASONAL DATA SUMMARIES FROM ACID DEPOSITION SYSTEM DATA BASE

    EPA Science Inventory

    The report gives a summary of 1985 wet deposition precipitation chemistry data collected in North America and available in the Acid Deposition System (ADS) data base. North American wet deposition monitoring networks with data in ADS are NADP/NTN, CANSAP, APN, UAPSP, MAP3S/PCN, W...

  1. The distribution of common construction materials at risk to acid deposition in the United States

    NASA Astrophysics Data System (ADS)

    Lipfert, Frederick W.; Daum, Mary L.

    Information on the geographic distribution of various types of exposed materials is required to estimate the economic costs of damage to construction materials from acid deposition. This paper focuses on the identification, evaluation and interpretation of data describing the distributions of exterior construction materials, primarily in the United States. This information could provide guidance on how data needed for future economic assessments might be acquired in the most cost-effective ways. Materials distribution surveys from 16 cities in the U.S. and Canada and five related databases from government agencies and trade organizations were examined. Data on residential buildings are more commonly available than on nonresidential buildings; little geographically resolved information on distributions of materials in infrastructure was found. Survey results generally agree with the appropriate ancillary databases, but the usefulness of the databases is often limited by their coarse spatial resolution. Information on those materials which are most sensitive to acid deposition is especially scarce. Since a comprehensive error analysis has never been performed on the data required for an economic assessment, it is not possible to specify the corresponding detailed requirements for data on the distributions of materials.

  2. Do the paleolimnological reconstructions reflect the influence of acid deposition?

    SciTech Connect

    Smirnov, D.Y.

    1996-12-31

    The using possibility of paleolimnological analyses was considered with the documentation aim of acid-forming substances distant transfer on territory of Northern Fennoscandia. The Holocene and ancient interglacial lakes pH-and alkalinity trends, reconstructed by means of bottom sediments diatomic analyses, were studied. It has been made evident that the tendency to sharp changes of these data is revealed on final stages of interglacial periods. At that time the high amplitude of climatic changes with low periodicity is resulting in catastrophic changes of landscapes in the frames of water-catchments bodies. During the last millennium the climatic situation in the Northern Fennoscandia was changing repeatedly (Medieval Warm Epoch, Little Ice Age, the rise in temperature in 20-40`s of XXth century). In the Little Ice Age (XVI-XIX centuries) the decrease of average annual temperature and intensification of winds velocity have caused a rapid retreat of latitudinal and high-altitude forest boundaries, accompanied by sharp reconstruction of tundra-,forest-tundra-and northern taiga landscapes. These processes have accelerated due to the enforcement of economic activity which caused the destruction of vegetation cover (salt-working, and ship-building since the XIXth century, pasture of reindeer herds since the end of XIXth century). Acidifying of ground and surface waters in the current century could be caused by the increased entry of organic acids, as a result of plant residues decomposition. The decomposition process was activated in the end of XIXth - beginning of XXth century in connection with the rise of temperature and increase of precipitation. Thus, the trends in pH and alkalinity changes in this region can not be used as indicators of acid-forming substances atmospheric deposition increase.

  3. Damage spreading in the Bak-Sneppen and ballistic deposition models: critical dynamics and nonextensivity

    NASA Astrophysics Data System (ADS)

    Lyra, Marcelo L.; Tirnakli, Ugur

    2004-06-01

    We introduce a new damage spreading algorithm which is able to capture both the long-time and short-time dynamics of extended systems which evolves towards a critical statistically stationary state. In this sense, the dynamics of systems exhibiting self-organized critical states is shown to be similar to the one observed at the usual critical point of continuous phase transitions and at the onset of chaos of nonlinear low-dimensional dynamical maps. The proposed algorithm is applied to the Bak-Sneppen model of biological evolution and the ballistic deposition model of surface growth. The critical dynamics of these models are discussed within the framework of a nonextensive statistics formalism.

  4. Damage mechanisms in thin film solar cells during sputtering deposition of transparent conductive coatings

    SciTech Connect

    Fan Qihua; Liao Xianbo; Deng, Michael; Deng Xunming

    2009-02-01

    Amorphous silicon (a-Si) based thin film solar cell grown on flexible stainless steel substrate is one of the most promising energy conversion devices in the future. This type of solar cell uses a transparent conductive oxide (TCO) film as top electrode. It has been a widely accepted opinion that the radio frequency sputtering deposition of the TCO film produces a higher yield than direct current sputtering, and the reason is not clear. Here we show that the damage to the solar cell during the sputtering process is caused by a reverse bias applied to the n-i-p junction. This reverse bias is related to the characteristics of plasma discharge. The mechanism we reveal may significantly affect the solar cell process.

  5. Energy-Deposition and Damage Calculations in Core-Vessel Inserts at the Spallation Neutron Source

    SciTech Connect

    Murphy, B.D.

    2002-06-25

    Heat-deposition and damage calculations are described for core-vessel inserts in the target area of the Spallation Neutron Source. Two separate designs for these inserts (or neutron beam tubes) were studied; a single-unit insert and a multi-unit insert. The single unit contains a neutron guide; the multi unit does not. Both units are constructed of stainless steel. For the single unit, separate studies were carried out with the guide composed of stainless steel, glass, and aluminum. Results are also reported for an aluminum window on the front of the insert, a layer of nickel on the guide, a cadmium shield surrounding the guide, and a stainless steel plug in the beam-tube opening. The locations of both inserts were the most forward positions to be occupied by each design respectively thus ensuring that the calculations are conservative.

  6. Characterization of 1064nm nanosecond laser-induced damage on antireflection coatings grown by atomic layer deposition.

    PubMed

    Liu, Zhichao; Chen, Songlin; Ma, Ping; Wei, Yaowei; Zheng, Yi; Pan, Feng; Liu, Hao; Tang, Gengyu

    2012-01-16

    Damage tests are carried out at 1064nm to measure the laser resistance of TiO(2)/Al(2)O(3) and HfO(2)/Al(2)O(3) antireflection coatings grown by atomic layer deposition (ALD). The damage results are determined by S-on-1 and R-on-1 tests. Interestingly, the damage performance of ALD coatings is similar to those grown by conventional e-beam evaporation process. A decline law of damage resistance under multiple irradiations is revealed. The influence of growth temperature on damage performance has been investigated. Result shows that the crystallization of TiO(2) layer at higher temperature could lead to numerous absorption defects that reduce the laser-induced damage threshold (LIDT). In addition, it has been found that using inorganic compound instead of organic compound as precursors for ALD process maybe effectively prevent carbon impurities in films and will increase the LIDT obviously. PMID:22274431

  7. Can insect egg deposition ‘warn’ a plant of future feeding damage by herbivorous larvae?

    PubMed Central

    Beyaert, Ivo; Köpke, Diana; Stiller, Josefin; Hammerbacher, Almuth; Yoneya, Kinuyo; Schmidt, Axel; Gershenzon, Jonathan; Hilker, Monika

    2012-01-01

    Plant anti-herbivore defence is inducible by both insect feeding and egg deposition. However, little is known about the ability of insect eggs to induce defences directed not against the eggs themselves, but against larvae that subsequently hatch from the eggs. We studied how oviposition (OP) by the sawfly Diprion pini on Pinus sylvestris foliage affects the plant's defensive potential against sawfly larvae. Larvae that initiated their development on P. sylvestris twigs on which they hatched from eggs gained less weight and suffered higher mortality than those fed on egg-free twigs. The poor performance of these larvae also affected the next herbivore generation since fecundity of resulting females was lower than that of females which spent their larval development on egg-free pine. Transcript levels of P. sylvestris sesquiterpene synthases (PsTPS1, PsTPS2) were increased by D. pini OP, reached their highest levels just before larval hatching, and decreased when larvae started to feed. However, concentrations of terpenoid and phenolic metabolites presumed to act as feeding deterrents or toxins for herbivores did not change significantly after OP and feeding. Nevertheless, our performance data suggest that insect egg deposition may act to ‘warn’ a plant of upcoming feeding damage by larvae. PMID:21561977

  8. The influence of a small amount of maleic acid on crystal deposition phenomena of methacrylic acid in melt crystallization

    NASA Astrophysics Data System (ADS)

    Hino, Tomomichi; Kato, Shinpei; Takiyama, Hiroshi

    2013-06-01

    Crystal deposition phenomena were investigated in the suspension melt crystallization of an organic acid. Methacrylic acid was used as the target substance, a certain amount of methanol was used as the solvent, and the effect of a small amount of maleic acid by-produced in methacrylic acid synthesis was focused on. Batch crystallizations were carried out on a laboratory scale using various concentrations of maleic acid. In the presence of maleic acid, a certain deviation from equilibrium of the pure binary system was observed in the final composition of mother liquor. Moreover, nevertheless the final temperature in the crystallizer was same, the amount of crystal deposition in the presence of maleic acid was smaller than in the absence of maleic acid. It was suggested that the final amount of crystal deposition decreased in the presence of maleic acid. Additionally, it was observed that the obtained crystal size was smaller in the presence of maleic acid. Hence, a simplified kinetic analysis of crystal deposition rates was carried out to make the effect of maleic acid clear. Consequently, it was suggested that the cause of the above-mentioned phenomena was the existence of the maleic acid concentration dependent pseudo-liquidus line.

  9. U.S. EPA WORKSHOP TO DEVELOP A SIMPLE MODEL FOR ACID DEPOSITION

    EPA Science Inventory

    The Acid Deposition Planning Staff in the Office of Acid Deposition/EPA requested that the Atmospheric Sciences Research Laboratory undertake the development of a low-computational-demanding model suitable for educational use in understanding the linear or non-linear nature of th...

  10. PROTOTYPE CONCENTRATION MONITOR FOR ESTIMATING ACIDIC DRY DEPOSITION

    EPA Science Inventory

    Dry deposition contributes significantly to the acidification of the ecosystem. However, difficulties in measuring dry deposition of reactive gases and fine particles make routine direct monitoring impractical. An alternate approach is to use the 'concentration monitoring' method...

  11. A biogeochemical comparison of two well-buffered catchments with contrasting histories of acid deposition

    USGS Publications Warehouse

    Shanley, J.B.; Kram, P.; Hruska, J.; Bullen, T.D.

    2004-01-01

    Much of the biogeochemical cycling research in catchments in the past 25 years has been driven by acid deposition research funding. This research has focused on vulnerable base-poor systems; catchments on alkaline lithologies have received little attention. In regions of high acid loadings, however, even well-buffered catchments are susceptible to forest decline and episodes of low alkalinity in streamwater. As part of a collaboration between the Czech and U.S. Geological Surveys, we compared biogeochemical patterns in two well-studied, well-buffered catchments: Pluhuv Bor in the western Czech Republic, which has received high loading of atmospheric acidity, and Sleepers River Research Watershed in Vermont, U.S.A., where acid loading has been considerably less. Despite differences in lithology, wetness, forest type, and glacial history, the catchments displayed similar patterns of solute concentrations and flow. At both catchments, base cation and alkalinity diluted with increasing flow, whereas nitrate and dissolved organic carbon increased with increasing flow. Sulfate diluted with increasing flow at Sleepers River, while at Pluhuv Bor the sulfate-flow relation shifted from positive to negative as atmospheric sulfur (S) loadings decreased and soil S pools were depleted during the 1990s. At high flow, alkalinity decreased to near 100 ??eq L-1 at Pluhuv Bor compared to 400 ??eq L-1 at Sleepers River. Despite the large amounts of S flushed from Pluhuv Bor soils, these alkalinity declines were caused solely by dilution, which was greater at Pluhuv Bor relative to Sleepers River due to greater contributions from shallow flow paths at high flow. Although the historical high S loading at Pluhuv Bor has caused soil acidification and possible forest damage, it has had little effect on the acid/base status of streamwater in this well-buffered catchment. ?? 2004 Kluwer Academic Publishers.

  12. Acid deposition and air quality related values in north central Colorado wilderness areas. Final report

    SciTech Connect

    Hidy, G.M.

    1995-05-01

    Terrestrial and aquatic ecosystem response to atmospheric acid, sulfur, and nitrate deposition has been studied only in a very limited way in Colorado wilderness areas. However, the observed deposition rates in north central Colorado remain low relative to affected areas in the eastern United States and well within a range where no adverse ecological effects are expected. This report presents a survey of scientific information describing acid deposition and air quality related values, which may have implications for utility plant operations.

  13. Ascorbic acid protects lipids in human plasma and low-density lipoprotein against oxidative damage

    SciTech Connect

    Frei, B. )

    1991-12-01

    The authors exposed human blood plasma and low-density lipoprotein (LDL) to many different oxidative challenges and followed the temporal consumption of endogenous antioxidants in relation to the initiation of oxidative damage. Under all types of oxidizing conditions, ascorbic acid completely protects lipids in plasma and LDL against detectable peroxidative damage as assessed by a specific and highly sensitive assay for lipid peroxidation. Ascorbic acid proved to be superior to the other water-soluble plasma antioxidants bilirubin, uric acid, and protein thiols as well as to the lipoprotein-associated antioxidants alpha-tocopherol, ubiquinol-10, lycopene, and beta-carotene. Although these antioxidants can lower the rate of detectable lipid peroxidation, they are not able to prevent its initiation. Only ascorbic acid is reactive enough to effectively intercept oxidants in the aqueous phase before they can attack and cause detectable oxidative damage to lipids.

  14. Acid rain and weathering damage to carbonate building stone

    SciTech Connect

    Reddy, M.M.; Youngdahl, C.A.

    1987-07-01

    Marble and limestone specimens were exposed to atmospheric conditions at four eastern US sites. A number of methods were used for damage assessment; this paper describes the results of chemical and physical measurements of material loss. Good agreement was observed among the results obtained with different methods. A surface recession rate near 15 ..mu..m/y was observed for skyward surfaces of marble tested in NC, and comparable results were obtained at the other test sites. The response of the porous limestone was assessed with greater difficulty; a loss rate similar to that of marble was inferred. Initial correlations of material loss with environmental factors are briefly discussed.

  15. Investigations of low-temperature epitaxy, ion damage, and reactive-ion cleaning utilizing ion beam deposition

    SciTech Connect

    Appleton, B.R.; Zuhr, R.A.; Noggle, T.S.; Herbots, N.; Pennycook, S.J.

    1986-01-01

    The technique of ion beam deposition (IBD) is utilized to investigate low-energy, ion-induced damage on Si and Ge; to study reactive ion cleaning of Si and Ge; to fabricate amorphous isotopic heterostructures; and to fabricate and study the low-temperature epitaxial deposition of /sup 74/Ge on Ge(100), /sup 30/Si on Si(100), and /sup 74/Ge on Si(100). The techniques of ion scattering/channeling and cross-sectional TEM are combined to characterize the deposits.

  16. Epoetin beta pegol alleviates oxidative stress and exacerbation of renal damage from iron deposition, thereby delaying CKD progression in progressive glomerulonephritis rats.

    PubMed

    Hirata, Michinori; Tashiro, Yoshihito; Aizawa, Ken; Kawasaki, Ryohei; Shimonaka, Yasushi; Endo, Koichi

    2015-12-01

    The increased deposition of iron in the kidneys that occurs with glomerulopathy hinders the functional and structural recovery of the tubules and promotes progression of chronic kidney disease (CKD). Here, we evaluated whether epoetin beta pegol (continuous erythropoietin receptor activator: CERA), which has a long half-life in blood and strongly suppresses hepcidin-25, exerts renoprotection in a rat model of chronic progressive glomerulonephritis (cGN). cGN rats showed elevated urinary total protein excretion (uTP) and plasma urea nitrogen (UN) from day 14 after the induction of kidney disease (day 0) and finally declined into end-stage kidney disease (ESKD), showing reduced creatinine clearance with glomerulosclerosis, tubular dilation, and tubulointerstitial fibrosis. A single dose of CERA given on day 1, but not on day 16, alleviated increasing uTP and UN, thereby delaying ESKD. In the initial disease phase, CERA significantly suppressed urinary 8-OHdG and liver-type fatty acid-binding protein (L-FABP), a tubular damage marker. CERA also inhibited elevated plasma hepcidin-25 levels and alleviated subsequent iron accumulation in kidneys in association with elevated urinary iron excretion and resulted in alleviation of growth of Ki67-positive tubular and glomerular cells. In addition, at day 28 when the exacerbation of uTP occurs, a significant correlation was observed between iron deposition in the kidney and urinary L-FABP. In our study, CERA mitigated increasing kidney damage, thereby delaying CKD progression in this glomerulonephritis rat model. Alleviation by CERA of the exacerbation of kidney damage could be attributable to mitigation of tubular damage that might occur with lowered iron deposition in tubules. PMID:26634903

  17. Diamondoid naphthenic acids cause in vivo genetic damage in gills and haemocytes of marine mussels.

    PubMed

    Dissanayake, Awantha; Scarlett, Alan G; Jha, Awadhesh N

    2016-04-01

    Diamondoids are polycyclic saturated hydrocarbons that possess a cage-like carbon skeleton approaching that of diamond. These 'nano-diamonds' are used in a range of industries including nanotechnologies and biomedicine. Diamondoids were thought to be highly resistant to degradation, but their presumed degradation acid products have now been found in oil sands process-affected waters (OSPW) and numerous crude oils. Recently, a diamondoid-related structure, 3-noradamantane carboxylic acid, was reported to cause genetic damage in trout hepatocytes under in vitro conditions. This particular compound has never been reported in the environment but led us to hypothesise that other more environmentally relevant diamondoid acids could also be genotoxic. We carried out in vivo exposures (3 days, semi-static) of marine mussels to two environmentally relevant diamondoid acids, 1-adamantane carboxylic acid and 3,5-dimethyladamantane carboxylic acid plus 3-noradamantane carboxylic acid with genotoxic damage assessed using the Comet assay. An initial screening test confirmed that these acids displayed varying degrees of genotoxicity to haemocytes (increased DNA damage above that of controls) when exposed in vivo to a concentration of 30 μmol L(-1). In a further test focused on 1-adamantane carboxylic acid with varying concentrations (0.6, 6 and 30 μmol L(-1)), significant (P < 0.05%) DNA damage was observed in different target cells (viz. gills and haemocytes) at 0.6 μmol L(-1). Such a level of induced genetic damage was similar to that observed following exposure to a known genotoxin, benzo(a)pyrene (exposure concentration, 0.8 μmol L(-1)). These findings may have implications for a range of worldwide industries including oil extraction, nanotechnology and biomedicine. PMID:26884235

  18. ACID PRECIPITATION IN NORTH AMERICA: 1987 ANNUAL AND SEASONAL DATA SUMMARIES FROM ACID DEPOSITION SYSTEM DATA BASE

    EPA Science Inventory

    This report summarizes the 1987 wet deposition precipitation chemistry data collected in North America and available in the Acid Deposition System (ADS) data base. nterpretative statistical analyses are not a focus of this report; however, users of the report will learn about maj...

  19. ACID PRECIPITATION IN NORTH AMERICA: 1980, 1981 AND 1982 ANNUAL DATA SUMMARIES FROM ACID DEPOSITION SYSTEM DATA BASE

    EPA Science Inventory

    The Acid Deposition System (ADS) data base for North American wet deposition data is used to provide an overview of the major North American monitoring networks: NADP, CANSAP, APN, MAP3S/PCN, EPRI/SURE, UAPSP and APIOS daily and cumulative. Individual site annual statistical summ...

  20. Transcriptomic Analysis of Carboxylic Acid Challenge in Escherichia coli: Beyond Membrane Damage

    PubMed Central

    Royce, Liam A.; Boggess, Erin; Fu, Yao; Liu, Ping; Shanks, Jacqueline V.; Dickerson, Julie; Jarboe, Laura R.

    2014-01-01

    Carboxylic acids are an attractive biorenewable chemical. Enormous progress has been made in engineering microbes for production of these compounds though titers remain lower than desired. Here we used transcriptome analysis of Escherichia coli during exogenous challenge with octanoic acid (C8) at pH 7.0 to probe mechanisms of toxicity. This analysis highlights the intracellular acidification and membrane damage caused by C8 challenge. Network component analysis identified transcription factors with altered activity including GadE, the activator of the glutamate-dependent acid resistance system (AR2) and Lrp, the amino acid biosynthesis regulator. The intracellular acidification was quantified during exogenous challenge, but was not observed in a carboxylic acid producing strain, though this may be due to lower titers than those used in our exogenous challenge studies. We developed a framework for predicting the proton motive force during adaptation to strong inorganic acids and carboxylic acids. This model predicts that inorganic acid challenge is mitigated by cation accumulation, but that carboxylic acid challenge inverts the proton motive force and requires anion accumulation. Utilization of native acid resistance systems was not useful in terms of supporting growth or alleviating intracellular acidification. AR2 was found to be non-functional, possibly due to membrane damage. We proposed that interaction of Lrp and C8 resulted in repression of amino acid biosynthesis. However, this hypothesis was not supported by perturbation of lrp expression or amino acid supplementation. E. coli strains were also engineered for altered cyclopropane fatty acid content in the membrane, which had a dramatic effect on membrane properties, though C8 tolerance was not increased. We conclude that achieving higher production titers requires circumventing the membrane damage. As higher titers are achieved, acidification may become problematic. PMID:24586888

  1. Nephroprotective Effect of Ursolic Acid in a Murine Model of Gentamicin-Induced Renal Damage

    PubMed Central

    Pai, Preethi G.; Chamari Nawarathna, Savindika; Kulkarni, Avdhooth; Habeeba, Umma; Reddy C., Sudarshan; Teerthanath, Srinivas; Shenoy, Jnaneshwara P.

    2012-01-01

    The present study evaluates the nephroprotective effects of ursolic acid in a murine model of gentamicin induced renal damage. Wistar albino rats of either sex, weighing 150–200 g were divided into 5 groups; normal saline, gentamicin 80 mg/kg, intraperitoneally for 8 days, ursolic acid at 2, 5, and 10 mg/kg, per oral for 8 days, ursolic acid administered 3 days prior and concurrently with gentamicin for 5 days. Blood urea, serum creatinine, uric acid and blood urea nitrogen analyses and microscopic examination of kidney were performed. Gentamicin treatment caused nephrotoxicity as evidenced by marked elevation in serum urea, serum uric acid, serum creatinine and blood urea nitrogen (162.33 ± 9.92 mg/dL, 3.13 ± 0.12 mg/dL, 6.85 ± 0.35 mg/dL and 75.86 ± 4.64 mg/dL; resp.) when compared to the saline treated groups. Co-administration of ursolic acid with gentamicin decreased the rise in these parameters in a dose dependent manner. Histopathological analysis revealed epithelial loss with intense granular degeneration in gentamicin treated rats, whereas ursolic acid mitigated the severity of gentamicin-induced renal damage. To conclude, our data suggest that ursolic acid exhibits renoprotective effect in gentamicin induced renal damage and further studies on its mechanis of action are warranted. PMID:22811930

  2. Acidic deposition, cation mobilization, and biochemical indicators of stress in healthy red spruce

    SciTech Connect

    Shortle, W.C.; Smith, K.T.; Minocha, R.

    1997-05-01

    Dendrochemical and biochemical markers link stress in apparently healthy red spruce trees (Picea rubens) to acidic deposition. Previous reports related visible damage of trees at high elevations to root and soil processes. In this report, dendrochemical and foliar biochemical markers indicate perturbations in biological processes in healthy red spruce trees across the northeastern USA. Previous research on the dendrochemistry of red spruce stemwood indicated that under uniform environmental conditions, stemwood concentrations of Ca and Mg decreased with increasing radial distance from the pith. For nine forest locations, frequency analysis shows that 28 and 52% of samples of red spruce stemwood formed in the 1960s are enriched in Ca and Mg, respectively, relative to wood formed prior to and after the 1960s. This enrichment in trees throughout the northeastern USA may be interpretable as a signal of increased availability of essential cations in forest soils. Such a temporary increase in the availability of Ca and Mg could be caused by cation mobilization, a consequence of increased acidic deposition. During cation mobilization, essential and Ca and Mg as well as potentially harmful Al become more available for interaction with binding sites in the soil and absorbing roots. As conditions which favor cation mobilization continue, Ca and Mg can be leached or displaced from the soil. A measure of the interaction between Ca and Al is the Al/Ca binding ratio (molar charge ratio of exchangeable Al to exchangeable Ca). As the Al/Ca binding ratio in the root zone increased from 0.3 to 1.9, the foliar concentration of the biochemical stress marker putrescine also increased form 45 to 145 nm g{sup {minus}1}. The correlation of the putrescine concentration to the Al/Ca binding ratio (adj. r{sup 2} = 0.68, P <0.027) suggests that foliar stress may be linked to soil chemistry. 32 refs., 2 figs., 1 tab.

  3. Identification of research relating to the critical loads concept and its potential application to the regulation of acidic deposition

    SciTech Connect

    Bhatti, N.

    1993-12-01

    The overwhelming majority of strategies currently implemented to regulate acidic deposition have focused on source-based or emission-control techniques. In the past few years, however, the fact that such source-based. strategies may not be sufficient to prevent adverse ecological effects and may therefore need to be supplemented with other control options, such as receptor-based strategies, has become apparent. Partly in response to this insufficiency of regulatory controls, the US Congress has required the National Acid Precipitation Assessment Program to determine (1) what deposition levels are needed to prevent such ecological damage, (2) whether such safe deposition levels (i.e., critical loads) can realistically be identified, and (3) what the costs and benefits of attaining such deposition levels are. This report reviews and culls the existing research on these alternative control strategies, emphasizing the critical loads concept, to determine the advantages and limitations and the cost-benefit relationships associated with receptor-based control options. The results of this study indicate that in spite of the significant limitations associated with the critical loads concept, this strategy dominates all discussions of non-source-based control options and offers considerable advantages, including cost-effectiveness, over the more traditional source-based control methods. Summaries of 10 of the most relevant studies dealing with alternative control strategies and the costs and benefits associated with them are also presented in this report.

  4. Vacuolar deposition of ascorbate-derived oxalic acid in barley

    SciTech Connect

    Wagner, G.J.

    1981-03-01

    L-(1-/sup 14/C)Ascorbic acid was supplied to detached barley seedlings to determine the subcellular location of oxalic acid, one of its metabolic products. Intact vacuoles isolated from protoplasts of labeled leaves contained (/sup 14/C)oxalic acid which accounted for about 70% of the intraprotoplast soluble oxalic acid. Tracer-labeled oxalate accounted for 36 and 72% of the /sup 14/C associated with leaf vacuoles of seedlings labeled for 22 and 96 hours, respectively.

  5. Geochemical investigations of selected Eastern United States watersheds affected by acid deposition.

    USGS Publications Warehouse

    Bricker, O.P.

    1986-01-01

    The effects of acid deposition on surface waters in eastern USA watersheds of similar size, physiography, climate and land-use are related to the composition of the underlying bedrock. Watersheds developed on greenstone, calcareous shale, sandstone, granite and schist differ in their ability to neutralize acid rain; consequently, stream acidity is similar to that of precipitation. Watersheds developed on granite and schist are intermediate in their capacity to neutralize acid deposition. Bedrock composition appears to be the major property controlling surface-water chemistry in these systems; hydrological flowpaths and the nature of surficial materials and vegetation also influence chemical responses to acid deposition in watersheds. 453This and the following 10 abstracts are for papers forming a thematic set on geochemical aspects of acid rain. -P.Br.

  6. The solubility of aluminum in acidic forest soils: Long-term changes due to acid deposition

    NASA Astrophysics Data System (ADS)

    Mulder, Jan; Stein, Alfred

    1994-01-01

    Despite the ecological and pedogenic importance of Al, its solubility control in acidic forest soils is poorly understood. Here we discuss the solubility of Al and its development with time in three acid brown forest soils in The Netherlands, which are under extreme acidification from atmospheric deposition. All soil solutions (to a 60 cm depth) were undersaturated with respect to synthetic gibbsite (Al(OH) 3; log K = 9.12 at 8°C), with the highest degree of undersaturation occurring in the surface soil. In about one third of the individual soil layers a significant positive correlation existed between the activity of Al 3+ and H +, but this relationship was far less than cubic. Kinetically constrained dissolution of Al is unlikely to explain the disequilibrium with respect to gibbsite, because undersaturation was highest through summer when water residence times were longest and temperatures greatest. Time series analysis of six year data sets for several soil layers revealed a significant annual decline in soil solution pH and Al solubility (defined as log Al + 3 pH) despite a constant concentration of strong acid anions. The annual decline of both pH and Al solubility was greatest in the surface soil and was positively correlated with the relative depletion of reactive organically bound soil Al. The results support our earlier hypothesis that in strongly acidified forest soils complexation by solid phase organics controls the solubility of Al even in mineral soil layers, relatively low in organic C. The data lend no support to the current widespread and often uncritical use of gibbsite as a model for the Al solubility in highly acidic forest soils (pH < 4.5) of the temperate zone.

  7. A Calculation of Spatial Range of Colloidal Silicic Acid Deposited Downstream from the Alkali Front

    NASA Astrophysics Data System (ADS)

    Niibori, Yuichi; Iijima, Kazuki; Tamura, Naoyuki; Mimura, Hitoshi

    A high alkali domain spreads out due to the use of cement materials for the construction of the repository of radioactive wastes. Sudden change of pH at this alkali front produces colloidal silicic acid (polymeric silicic acid) in addition to the deposition of supersaturated monomeric silicic acid onto the fracture surface of flow-pathway. The colloidal silicic acid also deposits with relatively small rate-constant in the co-presence of solid phase. Once the flow-path surface is covered with the amorphous silica, the surface seriously degrades the sorption behavior of radionuclides (RNs). Therefore, so far, the authors have examined the deposition rates of supersaturated silicic acid. This study summarized the deposition rate-constants defined by the first-order reaction equation under various conditions of co-presence of amorphous silica powder. Then, using the smallest rate-constant (1.0×10-12 m/s in the co-presence of calcium ions of 1 mM) and a simulation code, COLFRAC-MRL, the spatial range of colloidal silicic acid deposited downstream from the alkali front was estimated. The results suggested the clogging caused by the deposition of colloidal silicic acid in flow-path. The altered spatial range in the flow-path was limited to around 30 m in fracture and to several centimeters in rock matrix.

  8. Acidic Deposition along the Appalachian Trail Corridor and its Effects on Acid-Sensitive Terrestrial and Aquatic Resources

    NASA Astrophysics Data System (ADS)

    Lawrence, G. B.; Sullivan, T. J.; Burns, D. A.; Bailey, S. W.; Cosby, B. J., Jr.; Dovciak, M.; Ewing, H. A.; McDonnell, T. C.; Riemann, R.; Quant, J.; Rice, K. C.; Siemion, J.; Weathers, K. C.

    2015-12-01

    The Appalachian National Scenic Trail (AT) spans 3,500 km from Georgia to Maine. Over its length, the trail passes through a corridor with wide variations in climate, bedrock type, soils, and stream water quality. These factors create a diverse range of ecosystems. The health of these ecosystems is a cause for concern because the AT passes through the heavily populated eastern U.S. with its many sources of sulfur (S) and nitrogen (N) emissions that produce acidic deposition. To address concerns about the health of the AT, a study was designed to evaluate the condition and sensitivity of the AT corridor with respect to acidic deposition. Collections of stream water (265 sites), soil (60 sites), tree cores (15 sites) and atmospheric deposition samples (4 sites) were made along with understory and overstory vegetation measurements (30 sites) over the full trail length within a 40 km-wide corridor. Existing data on atmospheric deposition, geology, vegetation, stream chemistry, and soil chemistry were also used in the analysis. Mean acid-neutralizing capacity (ANC) was lowest in the streams in the North section, intermediate in the Central section and highest the South section, despite the South having the highest acid rain levels. At least 40% of the study streams exhibited pH and/or Ali measurements that indicated potential harm to biota. Approximately 70% of the soil sites had values of base saturation under 20%, the threshold below which acidic deposition can mobilize inorganic aluminum (Ali), the form harmful to terrestrial and aquatic life. Compositional similarity of understory and canopy species was positively correlated with acidic deposition, suggesting that during past decades, species poorly adapted to acidic deposition were replaced with tolerant species. Target loads modeling indicated that exceedance of sulfur target loads to achieve stream ANC = 50 μeq/L by the year 2100occurred throughout the trail corridor.

  9. Cell to Cell Variability of Radiation-Induced Foci: Relation between Observed Damage and Energy Deposition.

    PubMed

    Gruel, Gaëtan; Villagrasa, Carmen; Voisin, Pascale; Clairand, Isabelle; Benderitter, Marc; Bottollier-Depois, Jean-François; Barquinero, Joan Francesc

    2016-01-01

    Most studies that aim to understand the interactions between different types of photon radiation and cellular DNA assume homogeneous cell irradiation, with all cells receiving the same amount of energy. The level of DNA damage is therefore generally determined by averaging it over the entire population of exposed cells. However, evaluating the molecular consequences of a stochastic phenomenon such as energy deposition of ionizing radiation by measuring only an average effect may not be sufficient for understanding some aspects of the cellular response to this radiation. The variance among the cells associated with this average effect may also be important for the behaviour of irradiated tissue. In this study, we accurately estimated the distribution of the number of radiation-induced γH2AX foci (RIF) per cell nucleus in a large population of endothelial cells exposed to 3 macroscopic doses of gamma rays from 60Co. The number of RIF varied significantly and reproducibly from cell to cell, with its relative standard deviation ranging from 36% to 18% depending on the macroscopic dose delivered. Interestingly, this relative cell-to-cell variability increased as the dose decreased, contrary to the mean RIF count per cell. This result shows that the dose effect, in terms of the number of DNA lesions indicated by RIF is not as simple as a purely proportional relation in which relative SD is constant with dose. To analyse the origins of this observed variability, we calculated the spread of the specific energy distribution for the different target volumes and subvolumes in which RIF can be generated. Variances, standard deviations and relative standard deviations all changed similarly from dose to dose for biological and calculated microdosimetric values. This similarity is an important argument that supports the hypothesis of the conservation of the association between the number of RIF per nucleus and the specific energy per DNA molecule. This comparison allowed us to

  10. Modeling dose deposition and DNA damage due to low-energy β(-) emitters.

    PubMed

    Alloni, D; Cutaia, C; Mariotti, L; Friedland, W; Ottolenghi, A

    2014-09-01

    One of the main issues of low-energy internal emitters concerns the very short ranges of the beta particles, versus the dimensions of the biological targets. Depending on the chemical form, the radionuclide may be more concentrated either in the cytoplasm or in the nucleus of the target cell. Consequently, since in most cases conventional dosimetry neglects this issue it may overestimate or underestimate the dose to the nucleus and hence the biological effects. To assess the magnitude of these deviations and to provide a realistic evaluation of the localized energy deposition by low-energy internal emitters, the biophysical track-structure code PARTRAC was used to calculate nuclear doses, DNA damage yields and fragmentation patterns for different localizations of radionuclides in human interphase fibroblasts. The nuclides considered in the simulations were tritium and nickel-63, which emit electrons with average energies of 5.7 (range in water of 0.42 μm) and 17 keV (range of 5 μm), respectively, covering both very short and medium ranges of beta-decay products. The simulation results showed that the largest deviations from the conventional dosimetry occur for inhomogeneously distributed short-range emitters. For uniformly distributed radionuclides selectively in the cytoplasm but excluded from the cell nucleus, the dose in the nucleus is 15% of the average dose in the cell in the case of tritium but 64% for nickel-63. Also, the numbers of double-strand breaks (DSBs) and the distributions of DNA fragments depend on subcellular localization of the radionuclides. In the low- and medium-dose regions investigated here, DSB numbers are proportional to the nuclear dose, with about 50 DSB/Gy for both studied nuclides. In addition, DSB numbers on specific chromosomes depend on the radionuclide localization in the cell as well, with chromosomes located more peripherally in the cell nucleus being more damaged by short-ranged emitters in cytoplasm compared with chromosomes

  11. Cell to Cell Variability of Radiation-Induced Foci: Relation between Observed Damage and Energy Deposition

    PubMed Central

    Voisin, Pascale; Clairand, Isabelle; Benderitter, Marc; Bottollier-Depois, Jean-François; Barquinero, Joan Francesc

    2016-01-01

    Most studies that aim to understand the interactions between different types of photon radiation and cellular DNA assume homogeneous cell irradiation, with all cells receiving the same amount of energy. The level of DNA damage is therefore generally determined by averaging it over the entire population of exposed cells. However, evaluating the molecular consequences of a stochastic phenomenon such as energy deposition of ionizing radiation by measuring only an average effect may not be sufficient for understanding some aspects of the cellular response to this radiation. The variance among the cells associated with this average effect may also be important for the behaviour of irradiated tissue. In this study, we accurately estimated the distribution of the number of radiation-induced γH2AX foci (RIF) per cell nucleus in a large population of endothelial cells exposed to 3 macroscopic doses of gamma rays from 60Co. The number of RIF varied significantly and reproducibly from cell to cell, with its relative standard deviation ranging from 36% to 18% depending on the macroscopic dose delivered. Interestingly, this relative cell-to-cell variability increased as the dose decreased, contrary to the mean RIF count per cell. This result shows that the dose effect, in terms of the number of DNA lesions indicated by RIF is not as simple as a purely proportional relation in which relative SD is constant with dose. To analyse the origins of this observed variability, we calculated the spread of the specific energy distribution for the different target volumes and subvolumes in which RIF can be generated. Variances, standard deviations and relative standard deviations all changed similarly from dose to dose for biological and calculated microdosimetric values. This similarity is an important argument that supports the hypothesis of the conservation of the association between the number of RIF per nucleus and the specific energy per DNA molecule. This comparison allowed us to

  12. DEPOSITION OF SULFATE ACID AEROSOLS IN THE DEVELOPING HUMAN LUNG

    EPA Science Inventory

    Computations of aerosol deposition as affected by (i) aerosol hygroscopicity, (ii) human age, and (iii) respiratory intensity are accomplished using a validated mathematical model. he interactive effects are very complicated but systematic. ew general observations can be made; ra...

  13. Utilization of biologically generated acid for drilling fluid damage removal and uniform acid placement across long formation intervals

    SciTech Connect

    Almond, S.W.; Harris, R.E.; Penny, G.S.

    1995-12-31

    A method of drilling damage removal is presented which uses biologically generated acid (BGA) as the stimulation fluid. The BGA solution is not reactive during the actual pumping stage which allows its displacement into the reservoir to be controlled by the relatively low permeability of the near wellbore damage. Catalytic generation of acid occurs at a controlled rate once the BGA has been injected into the formation and results in uniform damage removal around the near wellbore region. The ability of BGA to be generated under a variety of temperature and pressure conditions and the compatibility evaluation of BGA with a variety of commonly used oil and water based drilling muds is first presented to establish some of the operational guidelines for BGA use. Drilling damage removal studies utilizing the modified API linear conductivity flow cell and carbonate material with BGA is presented to demonstrate the effectiveness of this stimulation fluid. Dual core flow test data is then presented which shows BGA`s ability and HCL`s inability to remove drilling damage over long horizontal intervals in carbonate formations.

  14. Student Knowledge of Scientific and Natural Resource Concepts Concerning Acidic Deposition.

    ERIC Educational Resources Information Center

    Brody, Michael; And Others

    1989-01-01

    Assessed is the level of scientific and natural resource knowledge possessed by fourth-, eighth- and eleventh-grade students. Misconceptions are noted. Discussed are implications for teaching about acidic deposition. (CW)

  15. LABORATORY AND FIELD EVALUATIONS OF EXTRANSENSITIVE SULFUR DIXOIDE AND NITROGEN DIOXIDE ANALYZERS FOR ACID DEPOSITION MONITORING

    EPA Science Inventory

    Studies of environmental acid deposition require monitoring of very low levels of several atmospheric pollutants. arious passive and active samplers have been used to collect integrated atmospheric samples for such studies. ontinuous analyzers offer an advantage because of their ...

  16. PHYSICAL DAMAGE FORMATION ON AUTOMOTIVE FINISHES DUE TO ACIDIC REAGENT EXPOSURE

    EPA Science Inventory

    Several types of automotive finishes with clear coatings were exposed to drops of acidic reagents at 54 degrees C. urface damage was examined using visual observations, reflection optical microscopy, SEM, EDS, and profilometry. eflection microscopy was the most useful technique f...

  17. PLASMID DNA DAMAGE CAUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    EPA Science Inventory

    Plasmid DNA damage caused by methylated arsenicals, ascorbic acid and human liver ferritin.

    Arsenic causes cancer in human skin, urinary bladder, lung, liver and kidney and is a significant world-wide public health problem. Although the metabolism of inorganic arsenic is ...

  18. Experimental Protoporphyria: Effect of Bile Acids on Liver Damage Induced by Griseofulvin

    PubMed Central

    Martinez, María del Carmen; Ruspini, Silvina Fernanda; Afonso, Susana Graciela; Meiss, Roberto; Buzaleh, Ana Maria

    2015-01-01

    The effect of bile acids administration to an experimental mice model of Protoporphyria produced by griseofulvin (Gris) was investigated. The aim was to assess whether porphyrin excretion could be accelerated by bile acids treatment in an attempt to diminish liver damage induced by Gris. Liver damage markers, heme metabolism, and oxidative stress parameters were analyzed in mice treated with Gris and deoxycholic (DXA), dehydrocholic (DHA), chenodeoxycholic, or ursodeoxycholic (URSO). The administration of Gris alone increased the activities of glutathione reductase (GRed), superoxide dismutase (SOD), alkaline phosphatase (AP), gamma glutamyl transpeptidase (GGT), and glutathione-S-transferase (GST), as well as total porphyrins, glutathione (GSH), and cytochrome P450 (CYP) levels in liver. Among the bile acids studied, DXA and DHA increased PROTO IX excretion, DXA also abolished the action of Gris, reducing lipid peroxidation and hepatic GSH and CYP levels, and the activities of GGT, AP, SOD, and GST returned to control values. However, porphyrin accumulation was not prevented by URSO; instead this bile acid reduced ALA-S and the antioxidant defense enzymes system activities. In conclusion, we postulate that DXA acid would be more effective to prevent liver damage induced by Gris. PMID:25945334

  19. PROJECTION OF RESPONSE OF TREES AND FORESTS TO ACIDIC DEPOSITION AND ASSOCIATED POLLUTANTS

    EPA Science Inventory

    In 1986 the National, Acid Precipitation Assessment Program (NAPAP) established the Forest Response Program (FRP) to assess the effects of acidic deposition and associated pollutants on forests. Modeling studies were developed in parallel with both field studies on the pattern an...

  20. Docosahexaenoic Acid Induces Oxidative DNA Damage and Apoptosis, and Enhances the Chemosensitivity of Cancer Cells

    PubMed Central

    Song, Eun Ah; Kim, Hyeyoung

    2016-01-01

    The human diet contains low amounts of ω-3 polyunsaturated fatty acids (PUFAs) and high amounts of ω-6 PUFAs, which has been reported to contribute to the incidence of cancer. Epidemiological studies have shown that a high consumption of fish oil or ω-3 PUFAs reduced the risk of colon, pancreatic, and endometrial cancers. The ω-3 PUFA, docosahexaenoic acid (DHA), shows anticancer activity by inducing apoptosis of some human cancer cells without toxicity against normal cells. DHA induces oxidative stress and oxidative DNA adduct formation by depleting intracellular glutathione (GSH) and decreasing the mitochondrial function of cancer cells. Oxidative DNA damage and DNA strand breaks activate DNA damage responses to repair the damaged DNA. However, excessive DNA damage beyond the capacity of the DNA repair processes may initiate apoptotic signaling pathways and cell cycle arrest in cancer cells. DHA shows a variable inhibitory effect on cancer cell growth depending on the cells’ molecular properties and degree of malignancy. It has been shown to affect DNA repair processes including DNA-dependent protein kinases and mismatch repair in cancer cells. Moreover, DHA enhanced the efficacy of anticancer drugs by increasing drug uptake and suppressing survival pathways in cancer cells. In this review, DHA-induced oxidative DNA damage, apoptotic signaling, and enhancement of chemosensitivity in cancer cells will be discussed based on recent studies. PMID:27527148

  1. Docosahexaenoic Acid Induces Oxidative DNA Damage and Apoptosis, and Enhances the Chemosensitivity of Cancer Cells.

    PubMed

    Song, Eun Ah; Kim, Hyeyoung

    2016-01-01

    The human diet contains low amounts of ω-3 polyunsaturated fatty acids (PUFAs) and high amounts of ω-6 PUFAs, which has been reported to contribute to the incidence of cancer. Epidemiological studies have shown that a high consumption of fish oil or ω-3 PUFAs reduced the risk of colon, pancreatic, and endometrial cancers. The ω-3 PUFA, docosahexaenoic acid (DHA), shows anticancer activity by inducing apoptosis of some human cancer cells without toxicity against normal cells. DHA induces oxidative stress and oxidative DNA adduct formation by depleting intracellular glutathione (GSH) and decreasing the mitochondrial function of cancer cells. Oxidative DNA damage and DNA strand breaks activate DNA damage responses to repair the damaged DNA. However, excessive DNA damage beyond the capacity of the DNA repair processes may initiate apoptotic signaling pathways and cell cycle arrest in cancer cells. DHA shows a variable inhibitory effect on cancer cell growth depending on the cells' molecular properties and degree of malignancy. It has been shown to affect DNA repair processes including DNA-dependent protein kinases and mismatch repair in cancer cells. Moreover, DHA enhanced the efficacy of anticancer drugs by increasing drug uptake and suppressing survival pathways in cancer cells. In this review, DHA-induced oxidative DNA damage, apoptotic signaling, and enhancement of chemosensitivity in cancer cells will be discussed based on recent studies. PMID:27527148

  2. DNA damage and oxidative stress induced by acetylsalicylic acid in Daphnia magna.

    PubMed

    Gómez-Oliván, Leobardo Manuel; Galar-Martínez, Marcela; Islas-Flores, Hariz; García-Medina, Sandra; SanJuan-Reyes, Nely

    2014-08-01

    Acetylsalicylic acid is a nonsteroidal anti-inflammatory widely used due to its low cost and high effectiveness. This compound has been found in water bodies worldwide and is toxic to aquatic organisms; nevertheless its capacity to induce oxidative stress in bioindicators like Daphnia magna remains unknown. This study aimed to evaluate toxicity in D. magna induced by acetylsalicylic acid in water, using oxidative stress and DNA damage biomarkers. An acute toxicity test was conducted in order to determine the median lethal concentration (48-h LC50) and the concentrations to be used in the subsequent subacute toxicity test in which the following biomarkers were evaluated: lipid peroxidation, oxidized protein content, activity of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, and level of DNA damage. Lipid peroxidation level and oxidized protein content were significantly increased (p<0.05), and antioxidant enzymes significantly altered with respect to controls; while the DNA damage were significantly increased (p<0.05) too. In conclusion, acetylsalicylic acid induces oxidative stress and DNA damage in D. magna. PMID:24747829

  3. Dietary conjugated linoleic acids increase intramuscular fat deposition and decrease subcutaneous fat deposition in Yellow Breed × Simmental cattle.

    PubMed

    Zhang, Haibo; Dong, Xianwen; Wang, Zhisheng; Zhou, Aiming; Peng, Quanhui; Zou, Huawei; Xue, Bai; Wang, Lizhi

    2016-04-01

    This study was conducted to estimate the effect of dietary conjugated linoleic acids (CLA) on intramuscular and subcutaneous fat deposition in Yellow Breed × Simmental cattle. The experiment was conducted for 60 days. The results showed that the average backfat thickness, (testicles + kidney + pelvic) fat percentage and subcutaneous fat percentage in dietary CLA were significantly lower than in the control group, while intramuscular the fat percentage was significantly higher. Compared to the control group, the Longissimus muscle enzyme activities of lipoprotein lipase (LPL), fatty acid synthase (FAS) and acetyl-coenzyme A carboxylase (ACC) in dietary CLA and the subcutaneous fat enzyme activities of LPL, hormone-sensitive lipase (HSL) and carnitine palmitoyltransferase-1 (CPT-1) were significantly increased. Similarly, compared to the control group, the Longissimus muscle sterol regulatory element binding protein 1 (SREBP-1), FAS, stearoyl-coenzyme A desaturase (SCD), ACC, peroxisome proliferator-activated receptor γ (PPARγ), heart fatty-acid binding protein (H-FABP) and LPL gene expression in dietary CLA were significant increased, as were the subcutaneous fat of PPARγ, H-FABP, LPL, CPT-1 and HSL in dietary CLA. These results indicated that dietary CLA increases IMF deposition mainly by the up-regulation of lipogenic gene expression, while decreasing subcutaneous fat deposition mainly by the up-regulation of lipolytic gene expression. PMID:26582037

  4. Involvement of phylogenetically conserved acidic amino acid residues in catalysis by an oxidative DNA damage enzyme formamidopyrimidine glycosylase.

    PubMed

    Lavrukhin, O V; Lloyd, R S

    2000-12-12

    Formamidopyrimidine glycosylase (Fpg) is an important bacterial base excision repair enzyme, which initiates removal of damaged purines such as the highly mutagenic 8-oxoguanine. Similar to other glycosylase/AP lyases, catalysis by Fpg is known to proceed by a nucleophilic attack by an amino group (the secondary amine of its N-terminal proline) on C1' of the deoxyribose sugar at a damaged base, which results in the departure of the base from the DNA and removal of the sugar ring by beta/delta-elimination. However, in contrast to other enzymes in this class, in which acidic amino acids have been shown to be essential for glycosyl and phosphodiester bond scission, the catalytically essential acidic residues have not been documented for Fpg. Multiple sequence alignments of conserved acidic residues in all known bacterial Fpg-like proteins revealed six conserved glutamic and aspartic acid residues. Site-directed mutagenesis was used to change glutamic and aspartic acid residues to glutamines and asparagines, respectively. While the Asp to Asn mutants had no effect on the incision activity on 8-oxoguanine-containing DNA, several of the substitutions at glutamates reduced Fpg activity on the 8-oxoguanosine DNA, with the E3Q and E174Q mutants being essentially devoid of activity. The AP lyase activity of all of the glutamic acid mutants was slightly reduced as compared to the wild-type enzyme. Sodium borohydride trapping of wild-type Fpg and its E3Q and E174Q mutants on 8-oxoguanosine or AP site containing DNA correlated with the relative activity of the mutants on either of these substrates. PMID:11106507

  5. BPC-15 reduces trinitrobenzene sulfonic acid-induced colonic damage in rats.

    PubMed

    Veljaca, M; Lesch, C A; Pllana, R; Sanchez, B; Chan, K; Guglietta, A

    1995-01-01

    The effect of BPC-15 (Booly Protection Compound-15) was evaluated in a rat model of colonic injury. A single intracolonic administration of trinitrobenzene sulfonic acid (TNBS) dissolved in ethanol induces severe colonic damage, which is characterized by areas of necrosis surrounded by areas of acute inflammation. The damage is associated with high myeloperoxidase (MPO) activity, mainly as a reflection of neutrophilic infiltration into the damaged tissue. In this study, 1 hr before a single intracolonic administration of 50 mg/kg of TNBS in 50% ethanol, the animals were treated with one of the following doses of BPC-15: 0.0001, 0.001, 0.01, 0.1, 1 or 10 nmol/kg administered i.p. or with a dose of 10 nmol/kg administered intracolonically. The animals were sacrificed 3 days later and the extent of colonic necrosis and hyperemia was measured with an image analyzer. The i.p. administration of BPC-15 significantly reduced the extent of TNBS-induced colonic damage in a dose-dependent manner. This was associated with a statistically significant and dose-dependent reduction in colonic tissue MPO activity. At the dose tested (10 nmol/kg), intracolonic administration of BPC-15 did not significantly reduce either the extent of the colonic damage or the increase in MPO activity induced by TNBS. In conclusion, this study showed that i.p. administration of BPC-15 reduced TNBS-induced colonic damage in rats. PMID:7815358

  6. Quantification of hydrochloric acid and particulate deposition resulting from space shuttle launches at John F. Kennedy space center, Florida, USA

    NASA Astrophysics Data System (ADS)

    Dreschel, Thomas W.; Hall, Carlton R.

    1990-07-01

    Observations of damage to vegetation, acute reductions in surface water pH, and kills of small fish prompted the Biomedical Operations and Research Office at the John F. Kennedy Space Center to initiate intensive environmental evaluations of possible acute and long-term chronic impacts that may be produced by repeated launches of the space shuttle. An important step in this evaluation was the identification of deposition patterns and the quantification of ecosystem loading rates of exhaust constituents from the solid rocket motors (SRMs) in the area of the launch pad. These constituents are primarily aluminum oxide (Al2O3) and hydrochloric acid (HCl). During three launches of the space transportation system (STS-11, 13, and 14) up to 100 bulk deposition collectors, 83 mm in diameter containing 100 ml of deionized water, were deployed in a grid pattern covering 12.6 ha north of launch pad 39-A. Estimates of HCl and particulate deposition levels were made based on laboratory measurements of items entrained in the collectors. Captured particulates consisted of a variety of items including Al2O3, sand grains, sea shell fragments, paint chips, and other debris ablated from the launch pad surface by the initial thrust of the SRMs. Estimated ranges of HCl and particulate deposition in the study area were 0-127 g/m2 and 0-246 g/m2, respectively. Deposition patterns were highly influenced by wind speed and direction. These measurements indicate that, under certain meteorological conditions, up to 7.1 × 103 kg of particulates and 3.4 × 103 kg of HCl can be deposited to the near-field environment beyond the launch pad perimeter fence.

  7. Acidic deposition in the northeastern United States: Sources and inputs, ecosystem effects, and management strategies

    USGS Publications Warehouse

    Driscoll, C.T.; Lawrence, G.B.; Bulger, A.J.; Butler, T.J.; Cronan, C.S.; Eagar, C.; Lambert, K.F.; Likens, G.E.; Stoddard, J.L.; Weathers, K.C.

    2001-01-01

    North America and Europe are in the midst of a large-scale experiment. Sulfuric and nitric acids have acidified soils, lakes, and streams, thereby stressing or killing terrestrial and aquatic biota. It is therefore critical to measure and to understand the recovery of complex ecosystems in response to decreases in acidic deposition. Fortunately, the NADP, CASTNet, and AIRMoN-dry networks are in place to measure anticipated improvements in air quality and in atmospheric deposition. Unfortunately, networks to measure changes in water quality are sparse, and networks to monitor soil, vegetation, and fish responses are even more limited. There is an acute need to assess the response of these resources to decreases in acid loading. It would be particularly valuable to assess the recovery of aquatic biota - which respond directly to acid stress - to changes in surface water chemistry (Gunn and Mills 1998). We used long-term research from the HBEF and other sites across the northeastern United States to synthesize data on the effects of acidic deposition and to assess ecosystem responses to reductions in emissions. On the basis of existing data, it is clear that in the northeastern United States ??? reductions of SO2 emissions since 1970 have resulted in statistically significant decreases in SO42- in wet and bulk deposition and in surface waters ??? emissions of NOX and concentrations of NO3- in wet and bulk deposition and in surface waters have shown no increase or decrease since the 1980s ??? estimates of NH3 emissions are uncertain, although atmospheric deposition of NH4+ remains important for forest management and stream NO3- loss ??? acidic deposition has accelerated the leaching of base cations from soils, thus delaying the recovery of ANC in lakes and streams from decreased emissions of SO2 (at the HBEF the available soil Ca pool appears to have declined 50% over the past 50 years) ???sulfur and N from atmospheric deposition have accumulated in forest soils across

  8. SPODOSOL VARIABILITY AND ASSESSMENT OF RESPONSE TO ACIDIC DEPOSITION

    EPA Science Inventory

    Variability in forest soils makes it difficult to observe short-term changes in chemical properties under field conditions. uried soil-bag technique was developed to examine the chemical response of a Maine forest soil to loadings of strong acids (HNO3 and H2SO4). cids were added...

  9. EFFECTS OF ACID DEPOSITION ON PAINTED WOOD SUBSTRATES

    EPA Science Inventory

    This report describes the progress that has been made within the Coatings Effect Research Program that EPA conducts for Task Group VII within the National Acid Precipitation Assessment Program (NAPAP). The major objective of this phase of the research program is to identify early...

  10. Direct damage to vegetation caused by acid rain and polluted cloud: definition of critical levels for forest trees.

    PubMed

    Cape, J N

    1993-01-01

    The concept of critical levels was developed in order to define short-term and long-term average concentrations of gaseous pollutants above which plants may be damaged. Although the usual way in which pollutants in precipitation (wet deposition) influence vegetation is by affecting soil processes, plant foliage exposed to fog and cloud, which often contain much greater concentrations of pollutant ions than rain, may be damaged directly. The idea of a critical level has been extended to define concentrations of pollutants in wet deposition above which direct damage to plants is likely. Concentrations of acidity and sulphate measured in mountain and coastal cloud are summarised. Vegetation at risk of injury is identified as montane forest growing close to the cloud base, where ion concentrations are highest. The direct effects of acidic precipitation on trees are reviewed, based on experimental exposure of plants to simulated acidic rain, fog or mist. Although most experiments have reported results in terms of pH (H(+) concentration), the accompanying anion is important, with sulphate being more damaging than nitrate. Both conifers and broadleaved tree seedlings showing subtle changes in the structural characteristics of leaf surfaces after exposure to mist or rain at or about pH 3.5, or sulphate concentration of 150 micromol litre(-1). Visible lesions on leaf surfaces occur at around pH 3 (500 micromol litre(-1) sulphate), broadleaved species tending to be more sensitive than conifers. Effects on photosynthesis and water relations, and interactions with other stresses (e.g. frost), have usually been observed only for treatments which have also caused visible injury to the leaf surface. Few experiments on the direct effects of polluted cloud have been conducted under field conditions with mature trees, which unlike seedlings in controlled conditions, may suffer a growth reduction in the absence of visible injury. Although leaching of cations (Ca(2+), Mg(2+), K(+)) is

  11. Pyridoxamine protects proteins from damage by hypohalous acids in vitro and in vivo.

    PubMed

    Madu, Hartman; Avance, Josh; Chetyrkin, Sergei; Darris, Carl; Rose, Kristie Lindsey; Sanchez, Otto A; Hudson, Billy; Voziyan, Paul

    2015-12-01

    Diabetes is characterized, in part, by activation of toxic oxidative and glycoxidative pathways that are triggered by persistent hyperglycemia and contribute to diabetic complications. Inhibition of these pathways may benefit diabetic patients by delaying the onset of complications. One such inhibitor, pyridoxamine (PM), had shown promise in clinical trials. However, the mechanism of PM action in vivo is not well understood. We have previously reported that hypohalous acids can cause disruption of the structure and function of renal collagen IV in experimental diabetes (K.L. Brown et al., Diabetes 64:2242-2253, 2015). In the present study, we demonstrate that PM can protect protein functionality from hypochlorous and hypobromous acid-derived damage via a rapid direct reaction with and detoxification of these hypohalous acids. We further demonstrate that PM treatment can ameliorate specific hypohalous acid-derived structural and functional damage to the renal collagen IV network in a diabetic animal model. These findings suggest a new mechanism of PM action in diabetes, namely sequestration of hypohalous acids, which may contribute to known therapeutic effects of PM in human diabetic nephropathy. PMID:26159508

  12. Amino acid geochemistry of fossil bones from the Rancho La Brea asphalt deposit, California

    USGS Publications Warehouse

    McMenamin, M.A.S.; Blunt, D.J.; Kvenvolden, K.A.; Miller, S.E.; Marcus, L.F.; Pardi, R.R.

    1982-01-01

    Low aspartic acid d:l ratios and modern collagenlike concentration values indicate that amino acids in bones from the Rancho La Brea asphalt deposit, Los Angeles, California are better preserved than amino acids in bones of equivalent age that have not been preserved in asphalt. Amino acids were recovered from 10 Rancho La Brea bone samples which range in age from less than 200 to greater than 36,000 yr. The calibrated rates of aspartic acid racemization range from 2.1 to 5.0 ?? 10-6yr-1. Although this wide range of rate constants decreases the level of confidence for age estimates, use of the larger rate constant of 5.0 ?? 10-6yr-1 provides minimum age estimates which fit the known stratigraphic and chronologic records of the Rancho La Brea deposits. ?? 1982.

  13. Growth of and mineral deposition in young rats fed saturated and unsaturated fatty acids

    SciTech Connect

    Magee, A.; D'Souza, D. John Hopkins Univ., Baltimore, MD )

    1991-03-15

    Male weanling rats were used in 4 week experiments to study effects of saturated and unsaturated fatty acids on growth and mineral deposition in several organs (bone, kidneys, liver, spleen, testes). Minerals evaluated were calcium, copper, iron, magnesium, manganese, phosphorus, and zinc, and levels of these minerals in tests diets were appropriate for growing rats. Two levels of dietary fat were used, and fatty acids included in the study were butyric/capronic, palmitic/stearic, oleic, and linoleic/linolenic acids. Decreased weight gains were observed in rats fed saturated fatty acids or 10% fat, while increases in weight gains were associated with increases in polyunsaturated/saturated (P/S) ratios. Copper, iron, or zinc levels tended to be higher in organs of rats fed saturated fatty acids. P/S ratios had no effect on copper or zinc deposition, but decreases in liver iron and increases in spleen iron were observed in rats fed the higher P/S ratios. Manganese levels were generally unaffected by fatty acid types, fat level, or P/S ratio, although liver manganese levels were higher in rats fed unsaturated fatty acids. Dietary fatty acids, fat level, or P/S ratios had no apparent effects on calcium, magnesium, phosphorus, or zinc deposition in femurs and tibias of rats.

  14. Chronic hyperuricemia, uric acid deposit and cardiovascular risk.

    PubMed

    Grassi, Davide; Ferri, Livia; Desideri, Giovambattista; Di Giosia, Paolo; Cheli, Paola; Del Pinto, Rita; Properzi, Giuliana; Ferri, Claudio

    2013-01-01

    Hyperuricemia is commonly associated with traditional risk factors such as dysglicemia, dyslipidemia, central obesity and abnormal blood pressure, i.e. the metabolic syndrome. Concordantly, recent studies have revived the controversy over the role of circulating uric acid, hyperuricemia, and gout as an independent prognostic factor for cardiovascular morbidity and mortality. In this regard, different studies also evaluated the possible role of xanthine inhibitors in inducing blood pressure reduction, increment in flow-mediated dilation, and improved cardiovascular prognosis in various patient settings. The vast majority of these studies have been conducted with either allopurinol or its active metabolite oxypurinol, i.e. two purine-like non-selective inhibitors of xanthine oxidase. More recently, the role of uric acid as a risk factor for cardiovascular disease and the possible protective role exerted by reduction of hyperuricemia to normal level have been evaluated by the use of febuxostat, a selective, non purine-like xanthine oxidase inhibitor. In this review, we will report current evidence on hyperuricemia in cardiovascular disease. The value of uric acid as a biomarker and as a potential therapeutic target for tailored old and novel "cardiometabolic" treatments will be also discussed. PMID:23173592

  15. Chronic Hyperuricemia, Uric Acid Deposit and Cardiovascular Risk

    PubMed Central

    Grassi, Davide; Ferri, Livia; Desideri, Giovambattista; Giosia, Paolo Di; Cheli, Paola; Pinto, Rita Del; Properzi, Giuliana; Ferri, Claudio

    2013-01-01

    Hyperuricemia is commonly associated with traditional risk factors such as dysglicemia, dyslipidemia, central obesity and abnormal blood pressure, i.e. the metabolic syndrome. Concordantly, recent studies have revived the controversy over the role of circulating uric acid, hyperuricemia, and gout as an independent prognostic factor for cardiovascular morbidity and mortality. In this regard, different studies also evaluated the possible role of xanthine inhibitors in inducing blood pressure reduction, increment in flow-mediated dilation, and improved cardiovascular prognosis in various patient settings. The vast majority of these studies have been conducted with either allopurinol or its active metabolite oxypurinol, i.e. two purine-like non-selective inhibitors of xanthine oxidase. More recently, the role of uric acid as a risk factor for cardiovascular disease and the possible protective role exerted by reduction of hyperuricemia to normal level have been evaluated by the use of febuxostat, a selective, non purine-like xanthine oxidase inhibitor. In this review, we will report current evidence on hyperuricemia in cardiovascular disease. The value of uric acid as a biomarker and as a potential therapeutic target for tailored old and novel “cardiometabolic” treatments will be also discussed. PMID:23173592

  16. Effects of acidic deposition on paint: A chamber study

    SciTech Connect

    Spence, J.W.; Lemmons, T.J.; Hou, Y.; Schadt, R.J.; Fornes, R.E.

    1993-08-01

    Exterior acrylic latex and alkyd architectural coatings were exposed to different conditions in a chamber exposure system involving simulated sunlight, dew, and photochemical smog-containing sulfur dioxide (SO2). A simulated sunlight exposure of the coating films in the presence of clean air was also incorporated into the experimental design. Changes in surface features after 1,370 hours of exposure were characterized by scanning electron microscope (SEM) and energy dispersive analysis of x-rays (EDAX). Gaseous species that deposited to the films were determined by ion chromatography of the dew collections. Color-change measurements of the exposed films were recorded as Delta E values. Latex and alkyd films that were formulated with calcium carbonate (CACO3) as an extender pigment were found to undergo the most change in surface features, composition, and color.

  17. Dry acid deposition on leaves of Ligustrum and a new surrogate leaf

    SciTech Connect

    Ondo, J.L.; John, W.; Wall, S.M.

    1984-01-01

    The dry deposition of acidic particles and gases on plants depends on micrometeorology in the canopy and on the surface structure of the leaves. The authors chose two methods to collect and analyze this deposition: washing sulfate and nitrate deposits from the leaves of two species of Ligustrum, an ornamental shrub, and using a surrogate leaf which would absorb acidic gases through pores into a reservoir. The plants are kept in 5-gallon pots in order to be transportable. The leaves are washed, then exposed for a given length of time. Then the leaves are harvested and extracted in distilled water. This extract is analyzed by ion chromatography for sulfate and nitrate. The surrogate leaf is constructed with a nuclepore filter membrane simulating the stomatal openings of a leaf. There is a moist filter in the interior leading to a reservoir. Sulfur dioxide and other acidic gases diffuse through the nuclepore pores and are absorbed in the moist filter. After exposure the exterior surfaces are washed to extract any dry particulate, and the interior filter is analyzed for dissolved acidic gases. The ''leaf'' is small enough to be placed in the canopy in field studies. This surrogate leaf has also been used as a passive monitor in indoor air pollution studies. The surrogate leaves and the ligustrum have been exposed side by side at sites in Berkeley and in the Los Angeles air basin. A comparison has been made between the deposition on natural leaves and the deposition on the artificial leaves.

  18. Nitric Acid-Sea Salt Reactions: Implications for Nitrogen Deposition to Water Surfaces.

    NASA Astrophysics Data System (ADS)

    Pryor, S. C.; Sørensen, L. L.

    2000-05-01

    Many previous studies have indicated the importance of nitric acid (HNO3) reactions on sea salt particles for flux divergence of HNO3 in the marine surface layer. The potential importance of this reaction in determining the spatial and temporal patterns of nitrogen dry deposition to marine ecosystems is investigated using models of sea spray generation and particle- and gas-phase dry deposition. Under horizontally homogeneous conditions with near-neutral stability and for wind speeds between 3.5 and 10 m s1, transfer of HNO3 to the particle phase to form sodium nitrate may decrease the deposition velocity of nitrogen by over 50%, leading to greater horizontal transport prior to deposition to the sea surface. Conversely, for wind speeds above 10 m s1, transfer of nitrogen to the particle phase would increase the deposition rate and hence decrease horizontal transport prior to surface removal.

  19. Electrophoretic deposition of hyaluronic acid and composite films for biomedical applications

    NASA Astrophysics Data System (ADS)

    Ma, R.; Li, Y.; Zhitomirsky, I.

    2010-06-01

    Hyaluronic acid (HYH) is a natural biopolymer, which has tremendous potential for various biomedical applications. Electrophoretic deposition (EPD) methods have been developed for the fabrication of HYH films and composites. New methods for the immobilization of drugs and proteins have been utilized for the fabrication of organic composites. Electrophoretic deposition enabled the fabrication of organic-inorganic composites containing bioceramics and bioglass in the HYH matrix. It was shown that the deposition yield, microstructure, and composition of the films can be controlled. Potential applications of EPD for the surface modification of biomedical implants and fabrication of biosensors are highlighted.

  20. Changes in soil pH across England and Wales in response to decreased acid deposition

    NASA Astrophysics Data System (ADS)

    Kirk, G. J. D.; Bellamy, P. H.

    2009-04-01

    In our recent analysis of data from the National Soil Inventory of England and Wales, we found widespread changes in soil pH across both countries between the two samplings of the Inventory. In general, soil pH increased - i.e. soils became less acid - under all land uses. The Inventory was first sampled in 1978-83 on a 5-km grid over the whole area. This yielded about 6,000 sites of which 5,662 could be sampled for soil. Roughly 40% of the sites were re-sampled at intervals from 12 to 25 years after the original sampling - in 1994/96 for agricultural land and in 2002/03 for non-agricultural. Exactly the same sampling and analytical protocols were used in the two samplings. In arable soils, the increase in pH was right across the range, whereas in grassland soils the main increase was at the acid end of the scale (pH < 5.5) with a small increase above pH 7. Some part of the change is likely to have been due to changes in land management. This includes better targeting of agricultural lime on acid soils; changes in nitrogen fertilizer use; deeper ploughing bringing up more calcareous subsoil on soils on calcareous materials; and so forth. However a major driver appears to have been decreased acid deposition to land. The total amounts of nitrogen compounds deposited were relatively unchanged over the survey period, but the amounts of acidifying sulphur compounds decreased by approximately 50%. We constructed a linear regression model to assess the relation between the rate of change in pH (normalised to an annual basis) and the rate of change in acid deposition, as modified by soil properties (pH, clay content, organic matter content), rainfall and past acid deposition. We used data on rainfall and acid deposition over the survey period on the same 5-km grid as the NSI data. We fitted the model separately for each land use category. The results for arable land showed a significant effect of the change in rate of acid deposition, though a significant part of the

  1. Descriptive risk assessment of the effects of acidic deposition on Rocky Mountain amphibians

    USGS Publications Warehouse

    Corn, Paul Stephen; Vertucci, Frank A.

    1992-01-01

    We evaluated the risk of habitat acidification to the six species of amphibians that occur in the mountains of Colorado and Wyoming. Our evaluation included extrinsic environmental factors (habitat sensitivity and amount of acidic atmospheric deposition) and species-specific intrinsic factors (sensitivity to acid conditions, habitat preferences, and timing of breeding). Only one of 57 surveyed localities had both acid neutralizing capacity μeq/L and sulfate deposition >10 kg/ha/yr, extrinsic conditions with a possible risk of acidification. Amphibian breeding habitats in the Rocky Mountains do not appear to be sufficiently acidic to kill amphibian embryos. Some species breed in high-elevation vernal pools during snowmelt, and an acidic pulse during snowmelt may pose a risk to embryos of these species. However, the acidic pulse, if present, probably occurs before open water appears and before breeding begins. Although inherent variability of amphibian population size may make detection of declines from anthropogenic effects difficult, acidic deposition is unlikely to have caused the observed declines of Bufo boreas and Rana pipiens in Colorado and Wyoming. Amphibians in the Rocky Mountains are not likely to be at risk with acidification inputs at present levels.

  2. Influence of Perfluorooctanoic Acid on the Transport and Deposition Behaviors of Bacteria in Quartz Sand.

    PubMed

    Wu, Dan; Tong, Meiping; Kim, Hyunjung

    2016-03-01

    The significance of perfluorooctanoic acid (PFOA) on the transport and deposition behaviors of bacteria (Gram-negative Escherichia coli and Gram-positive Bacillus subtilis) in quartz sand is examined in both NaCl and CaCl2 solutions at pH 5.6 by comparing both breakthrough curves and retained profiles with PFOA in solutions versus those without PFOA. All test conditions are found to be highly unfavorable for cell deposition regardless of the presence of PFOA; however, 7%-46% cell deposition is observed depending on the conditions. The cell deposition may be attributed to micro- or nanoscale roughness and/or to chemical heterogeneity of the sand surface. The results show that, under all examined conditions, PFOA in suspensions increases cell transport and decreases cell deposition in porous media regardless of cell type, presence or absence of extracellular polymeric substances, ionic strength, and ion valence. We find that the additional repulsion between bacteria and quartz sand caused by both acid-base interaction and steric repulsion as well as the competition for deposition sites on quartz sand surfaces by PFOA are responsible for the enhanced transport and decreased deposition of bacteria with PFOA in solutions. PMID:26866280

  3. Projection of response of trees and forests to acidic deposition and associated pollutants

    SciTech Connect

    Kiester, A.R.; Ford, E.D.; Avery, A.; Gay, C.; Droessler, T.

    1990-09-01

    In 1986 the National Acid Precipitation Assessment Program (NAPAP) established the Forest Response Program (FRP) to assess the effects of acidic deposition and associated pollutants on forests. Modeling studies were developed in parallel with both field studies on the pattern and trends of forest condition and physiological studies of seedlings, saplings, and branches of mature trees. The goals of the modeling effort were to simulate the dynamics of the processes by which acidic deposition and ozone affect tree physiological processes and therefore lead to changes in growth. Results from models of the physiological function of leaves, branches, roots, xylem, and canopies are presented here. These models illustrate three aspects of the dynamics of these processes. First, growth and the effects of pollutants are stochastic processes; that is, they vary randomly over time. The models help to account for the large amount of variability seen in normal field conditions. Second, some physiological processes can compensate for the effects of acidic deposition or ozone. Third, pollutants may have more than one effect on tree growth, and these effects may be synergistic. The potential nonlinearities and the variabilities demonstrated by these models lead to the conclusions that forest health effects may be developing that are not yet apparent; and for regulation of acidic deposition and associated pollutants to have a detectable effect, regulatory changes will probably have to be of substantial magnitude.

  4. Assessment of Damage to Nucleic Acids and Repair Machinery in Salmonella typhimurium Exposed to Chlorine

    PubMed Central

    Phe, M. H.; Hajj Chehade, M.; Guilloteau, H.; Merlin, C.; Block, J. C.

    2009-01-01

    Water disinfection is usually evaluated using mandatory methods based on cell culturability. However, such methods do not consider the potential of cells to recover, which should also be kept as low as possible. In this paper, we hypothesized that a successful disinfection is achieved only when the applied chlorine leads to both intracellular nucleic acid damage and strong alterations of the DNA repair machinery. Monitoring the SOS system responsiveness with a umuC’-‘lacZ reporter fusion, we found that the expression of this important cellular machinery was altered after the beginning of membrane permeabilization but prior to the total decline of both the cell culturability and the nucleic acid integrity as revealed by Sybr-II staining. Rapid measurement of such nucleic acid alterations by fluorochrome-based staining could be used as an alternative method for assessing the effectiveness of disinfection with chlorine. PMID:19936107

  5. Persistence of DNA damage following exposure of human bladder cells to chronic monomethylarsonous acid

    SciTech Connect

    Wnek, S.M.; Medeiros, M.K.; Eblin, K.E.; Gandolfi, A.J.

    2009-12-01

    Malignant transformation was demonstrated in UROtsa cells following 52-weeks of exposure to 50 nM monomethylarsonous acid (MMA{sup III}); the result was the malignantly transformed cell line, URO-MSC. URO-MSC cells were used to study the induction of DNA damage and the alteration of DNA repair enzymes in both the presence of MMA{sup III} [URO-MSC(+)] and after subsequent removal of MMA{sup III} [URO-MSC(-)] following chronic, low-level exposure. In the presence of MMA{sup III}, URO-MSC(+) cells demonstrated a sustained increase in DNA damage following 12-weeks of exposure; in particular, a significant increase in DNA single-strand breaks at 12-weeks of exposure consistently elevated through 52 weeks. The persistence of DNA damage in URO-MSC cells was assessed after a 2-week removal of MMA{sup III}. URO-MSC(-) cells demonstrated a decrease in DNA damage compared to URO-MSC(+); however, DNA damage in URO-MSC(-) remained significantly elevated when compared to untreated UROtsa and increased in a time-dependent manner. Reactive oxygen species (ROS) were demonstrated to be a critical component in the generation of DNA damage determined through the incubation of ROS scavengers with URO-MSC cells. Poly (ADP-ribose) polymerase (PARP) is a key repair enzyme in DNA single-strand break repair. URO-MSC(+) resulted in a slight increase in PARP activity after 36-weeks of MMA{sup III} exposure, suggesting the presence of MMA{sup III} is inhibiting the increase in PARP activity. In support, PARP activity in URO-MSC(-) increased significantly, coinciding with a subsequent decrease in DNA damage demonstrated in URO-MSC(-) compared to URO-MSC(+). These data demonstrate that chronic, low-level exposure of UROtsa cells to 50 nM MMA{sup III} results in: the induction of DNA damage that remains elevated upon removal of MMA{sup III}; increased levels of ROS that play a role in MMA{sup III} induced-DNA damage; and decreased PARP activity in the presence of MMA{sup III}.

  6. Iodoacetic acid, but not sodium iodate, creates an inducible swine model of photoreceptor damage.

    PubMed

    Noel, Jennifer M; Fernandez de Castro, Juan P; Demarco, Paul J; Franco, Luisa M; Wang, Wei; Vukmanic, Eric V; Peng, Xiaoyan; Sandell, Julie H; Scott, Patrick A; Kaplan, Henry J; McCall, Maureen A

    2012-04-01

    Our purpose was to find a method to create a large animal model of inducible photoreceptor damage. To this end, we tested in domestic swine the efficacy of two chemical toxins, known to create photoreceptor damage in other species: Iodoacetic Acid (IAA) and Sodium Iodate (NaIO(3)). Intravenous (IV) administration of NaIO(3) up to 90 mg/kg had no effect on retinal function and 110 mg/kg was lethal. IV administration of IAA (5-20 mg/kg) produced concentration-dependent changes in visual function as measured by full-field and multi-focal electroretinograms (ffERG and mfERG), and 30 mg/kg IAA was lethal. The IAA-induced effects measured at two weeks were stable through eight weeks post-injection, the last time point investigated. IAA at 7.5, 10, and 12 mg/kg produce a concentration-dependent reduction in both ffERG b-wave and mfERG N1-P1 amplitudes compared to baseline at all post-injection times. Comparisons of dark- and light-adapted ffERG b-wave amplitudes show a more significant loss of rod relative to cone function. The fundus of swine treated with ≥10 mg/kg IAA was abnormal with thinner retinal vessels and pale optic discs, and we found no evidence of bone spicule formation. Histological evaluations show concentration-dependent outer retinal damage that correlates with functional changes. We conclude that NaIO(3,) is not an effective toxin in swine. In contrast, IAA can be used to create a rapidly inducible, selective, stable and concentration-dependent model of photoreceptor damage in swine retina. Because of these attributes this large animal model of controlled photoreceptor damage should be useful in the investigation of treatments to replace damaged photoreceptors. PMID:22251455

  7. Fundamental Study on Temperature Dependence of Deposition Rate of Silicic Acid - 13270

    SciTech Connect

    Shinmura, Hayata; Niibori, Yuichi; Mimura, Hitoshi

    2013-07-01

    The dynamic behavior of the silicic acid is one of the key factors to estimate the condition of the repository system after the backfill. This study experimentally examined the temperature dependence of dynamic behavior of supersaturated silicic acid in the co-presence of solid phase, considering Na ions around the repository, and evaluated the deposition rate constant, k, of silicic acid by using the first-order reaction equation considering the specific surface area. The values of k were in the range of 1.0x10{sup -11} to 1.0x10{sup -9} m/s in the temperature range of 288 K to 323 K. The deposition rate became larger with increments of temperature under the Na ion free condition. Besides, in the case of Na ions 0.6 M, colloidal silicic acid decreased dramatically at a certain time. This means that the diameter of the colloidal silicic acid became larger than the pore size of filter (0.45 μm) due to bridging of colloidal silicic acid. Furthermore, this study estimated the range of altering area and the aperture of flow-path in various value of k corresponding to temperature by using advection-dispersion model. The concentration in the flow-path became lower with increments of temperature, and when the value of k is larger than 1.0x10{sup -11} m/s, the deposition range of supersaturated silicic acid was estimated to be less than 20 m around the repository. In addition, the deposition of supersaturated silicic acid led the decrement of flow-path aperture, which was remarkable under the condition of relatively high temperature. Such a clogging in flow paths is expected as a retardation effect of radionuclides. (authors)

  8. An overview of a 5-year research program on acid deposition in China

    NASA Astrophysics Data System (ADS)

    Wang, T.; He, K.; Xu, X.; Zhang, P.; Bai, Y.; Wang, Z.; Zhang, X.; Duan, L.; Li, W.; Chai, F.

    2011-12-01

    Despite concerted research and regulative control of sulfur dioxide in China, acid rain remained a serious environmental issue, due to a sharp increase in the combustion of fossil fuel in the 2000s. In 2005, the Ministry of Science and Technology of China funded a five-year comprehensive research program on acid deposition. This talk will give an overview of the activities and the key findings from this study, covering emission, atmospheric processes, and deposition, effects on soil and stream waters, and impact on typical trees/plants in China. The main results include (1) China still experiences acidic rainfalls in southern and eastern regions, although the situation has stabilized after 2006 due to stringent control of SO2 by the Chinese Government; (2) Sulfate is the dominant acidic compound, but the contribution of nitrate has increased; (3) cloud-water composition in eastern China is strongly influenced by anthropogenic emissions; (4) the persistent fall of acid rain in the 30 years has lead to acidification of some streams/rivers and soils in southern China; (5) the studied plants have shown varying response to acid rain; (6) some new insights have been obtained on atmospheric chemistry, atmospheric transport, soil chemistry, and ecological impacts, some of which will be discussed in this talk. Compared to the situation in North America and Europe, China's acid deposition is still serious, and continued control of sulfur and nitrogen emission is required. There is an urgent need to establish a long-term observation network/program to monitor the impact of acid deposition on soil, streams/rivers/lakes, and forests.

  9. Photoprotective Activity of Vulpinic and Gyrophoric Acids Toward Ultraviolet B-Induced Damage in Human Keratinocytes.

    PubMed

    Varol, Mehmet; Türk, Ayşen; Candan, Mehmet; Tay, Turgay; Koparal, Ayşe Tansu

    2016-01-01

    Vulpinic and gyrophoric acids are known as ultraviolet filters for natural lichen populations because of their chemical structures. However, to the best of our knowledge, there has been no reference to their cosmetic potential for skin protection against ultraviolet B (UVB)-induced damage and, consequently, we propose to highlight their photoprotective profiles in human keratinocytes (HaCaT). Therefore, vulpinic acid and gyrophoric acid were isolated from acetone extracts of Letharia vulpina and Xanthoparmelia pokornyi, respectively. Their photoprotective activities on irradiated HaCaT cells and destructive effects on non-irradiated HaCaT cells were compared through in vitro experimentation: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays, 4',6-diamino-2-phenylindole and tetramethylrhodamine B isothiocyanate-phalloidin staining protocols. Both of the lichen substances effectively prevented cytotoxic, apoptotic and cytoskeleton alterative activities of 2.5 J/cm(2) UVB in a dose-dependent manner. Moreover, vulpinic and gyrophoric acids showed no toxic, apoptotic or cytoskeleton alterative effects on non-irradiated HaCaT cells, except at high doses (≥400 μM) of gyrophoric acid. The findings suggest that vulpinic and gyrophoric acids can be promising cosmetic ingredients to photo-protect human skin cells and should therefore be further investigated by in vitro and in vivo multiple bioassays. PMID:26463741

  10. Elimination of a pollution associated with chromic acid during the electro-deposition of Cr(III) using appropriate anodic and membrane materials in a double film bath.

    PubMed

    Jiang, Xiaojun; Chen, Wenchao; Xu, Hongbo

    2009-01-01

    A method using trivalent chromium has been used to replace hexavalent chromium for the electro-deposition of chromium. Using a tri-chamber bath system various anodic materials and membranes were evaluated to minimize the production of environmentally and health damaging chromic acid. By measuring the absorbance of Cr(VI) at 640 nm, the results indicate that the use of a titanium plated ruthenium (Ti-Ru) anode produces the least amount of chromic acid byproduct compared to lead-gold alloy and graphite anodes. The concentration of Cr(VI) in the immediate vicinity of the Ti-Ru anode decreased from 0.389 mg/L to 0 during a 40-min deposition period. The use of a Nafion(TM) quaternary cation exchange membrane portioning the buffer and anode selectively prevented Cr(III) from entering the anode compartment whilst allowing the migration of H(+) to maintain overall voltaic continuity. It has been demonstrated that the use of a Ti-Ru anode with a Nafion(TM) membrane can eliminate the production of chromic acid associated with the electro-deposition of chromium plate thereby preventing its health damaging exposure to plant operators and preventing discharge of Cr(VI) into the environment. Addition of a surfactant improved current efficiency by 34.7%. PMID:25084432

  11. Integrated assessment of acid deposition impacts using reduced-form modeling. Final report

    SciTech Connect

    Sinha, R.; Small, M.J.

    1996-05-01

    Emissions of sulfates and other acidic pollutants from anthropogenic sources result in the deposition of these acidic pollutants on the earth`s surface, downwind of the source. These pollutants reach surface waters, including streams and lakes, and acidify them, resulting in a change in the chemical composition of the surface water. Sometimes the water chemistry is sufficiently altered so that the lake can no longer support aquatic life. This document traces the efforts by many researchers to understand and quantify the effect of acid deposition on the water chemistry of populations of lakes, in particular the improvements to the MAGIC (Model of Acidification of Groundwater in Catchments) modeling effort, and describes its reduced-form representation in a decision and uncertainty analysis tool. Previous reduced-form approximations to the MAGIC model are discussed in detail, and their drawbacks are highlighted. An improved reduced-form model for acid neutralizing capacity is presented, which incorporates long-term depletion of the watershed acid neutralization fraction. In addition, improved fish biota models are incorporated in the integrated assessment model, which includes reduced-form models for other physical and chemical processes of acid deposition, as well as the resulting socio-economic and health related effects. The new reduced-form lake chemistry and fish biota models are applied to the Adirondacks region of New York.

  12. Hyaluronic acid prevents immunosuppressive drug-induced ovarian damage via up-regulating PGRMC1 expression

    PubMed Central

    Zhao, Guangfeng; Yan, Guijun; Cheng, Jie; Zhou, Xue; Fang, Ting; Sun, Haixiang; Hou, Yayi; Hu, Yali

    2015-01-01

    Chemotherapy treatment in women can frequently cause damage to the ovaries, which may lead to primary ovarian insufficiency (POI). In this study, we assessed the preventative effects of hyaluronic acid (HA) in immunosuppressive drug-induced POI-like rat models and investigated the possible mechanisms. We found that HA, which was reduced in primary and immunosuppressant-induced POI patients, could protect the immunosuppressant-induced damage to granulosa cells (GCs) in vitro. Then we found that HA blocked the tripterygium glycosides (TG) induced POI-like presentations in rats, including delayed or irregular estrous cycles, reduced 17 beta-estradiol(E2) concentration, decreased number of follicles, destruction of follicle structure, and damage of reproductive ability. Furthermore, we investigated the mechanisms of HA prevention effects on POI, which was associated with promotion of GC proliferation and PGRMC1 expression. In conclusion, HA prevents chemotherapy-induced ovarian damage by promoting PGRMC1 in GCs. This study may provide a new strategy for prevention and treatment of POI. PMID:25558795

  13. [The peculiarities of deposition of foreign particles in the skin region experimentally damaged by the electrical saw cutting element].

    PubMed

    Nazarov, Yu V

    2015-01-01

    The objective of the present study was to detect the deposition of foreign particles and other introduced objects in the human skin region damaged by the electrical saw cutting elements and to use the data thus obtained for the estimation of the speed and the type of the instrument, the main characteristics of the cutter covering and/or composition of its surface. The experiments included the sawing of the skin fragments using the small steel saws differing in the type of the surface cover, such as the uncoated (steel), stained, nickel- or chromium-plated, blue-finished saws with the movement speed of the cutting element 500, 1000, 2500, 2,000, and 3,000 revolutions per minute. The study provided information about the peculiarities of deposition of foreign particles and other introduced objects in the damaged regions of the human skin that allow not only to establish the fact of using the electrical saw with a high-speed back-and-forth movements of the cutting element but also the type of the instrument and the main characteristics of its cover and/or the composition of its surface. PMID:26856056

  14. Global impacts of sulfate deposition from acid rain on methane emissions from natural wetlands.

    NASA Astrophysics Data System (ADS)

    Gauci, V.

    2003-04-01

    Natural wetlands form the largest methane (CH_4) source to the atmosphere. A collection of recent field and laboratory studies point to an anthropogenic control on CH_4 emissions from these systems: acid rain sulfate (SO_42-) deposition. These studies ranging from the UK, USA, Canada, Sweden and Czech Republic demonstrate that low rates of SO_42- deposition, within the range commonly experienced in acid rain impacted regions, can suppress CH_4 emissions by as much as 40% and that the response of CH_4 emissions to increasing rates of SO_42- deposition closely mirrors changes in sulfate reduction rates with SO_42- deposition. This indicates that the suppression in CH_4 flux is the result of acid rain stimulating a competitive exclusion of methanogenesis by sulfate reducing bacteria, resulting in reduced methane production. These findings were extrapolated to the global scale by combining modelled, spatially explicit data sets of CH_4 emission from wetlands across the globe with modelled S deposition. Results indicate that this interaction may be important at the global scale, suppressing CH_4 emissions from wetlands in 2030 by as much as 20--28Tg, and, in the process, offsetting predicted climate induced growth in the wetland CH_4 source.

  15. Enhanced acid rain and atmospheric deposition of nitrogen, sulfur and heavy metals in Northern China

    NASA Astrophysics Data System (ADS)

    Pan, Y.; Wang, Y.

    2013-12-01

    Atmospheric deposition is known to be important mechanism reducing air pollution. In response to the growing concern on the potential effects of the deposited material entering terrestrial and aquatic environments as well as their subsequent health effects, since 2007 we have established a 10-site monitoring network in Northern China, where particularly susceptible to severe air pollution. Wet and dry deposition was collected using an automatic wet-dry sampler. The presentation will focus on the new results of atmospheric deposition flux for a number of chemical species, such as nutrients (e.g. nitrogen and phosphorus), acidic matters (e.g. sulfur and proton), heavy metals and Polycyclic Aromatic Hydrocarbons, etc. This is to our knowledge the first detailed element budget study in the atmosphere across Northern China. We find that: (1) Over the 3 year period, 26% of precipitation events in the target area were more acid than pH 5.60 and these acidic events occurred in summer and autumn. The annual volume-weighted mean (VWM) pH value of precipitation was lower than 5.60 at most sites, which indicated the acidification of precipitation was not optimistic. The primary ions in precipitation were NH4+, Ca2+, SO42- and NO3-, with 10-sites-average concentrations of 221, 216, 216 and 80 μeq L-1, respectively. The ratio of SO42- to NO3- was 2.7; suggesting SO42- was the dominant acid component. (2) The deposited particles were neutral in general and the pH value increased from rural area to industrial and coastal sites. It is not surprising to note that the annual VWM pH value of precipitation was higher than 5.60 at three urban sites (Beijing and Tianjin mega cities) and one coastal site near the Bohai Bay, considering the fact that high buffer capacity of alkaline component, gas NH3 and mineral aerosols, at these sites compared to other places. (3) The 10-sites annual total deposition amounts for sulfur and nitrogen compounds were 60 and 65 kg N/S ha-1 yr-1

  16. Preparation of waxes and humic acids from brown coal from the Sergeevskoe deposit

    SciTech Connect

    L.P. Noskova; A.V. Rokhin; A.P. Sorokin

    2007-06-15

    The comparative extraction of coal with organic solvents was performed. Humic acids were separated from solid residues. The yields, particle-size distributions, and chemical compositions of the resulting products were analyzed. It was demonstrated that brown-coal wax and humic fertilizers can potentially be obtained using coal from the Sergeevskoe deposit.

  17. EFFECT OF SOIL PROCESSES ON THE ACIDIFICATION OF WATER BY ACID DEPOSITION

    EPA Science Inventory

    The mechanism whereby acid deposition can cause acidification of surface waters via equilibrium processes in soil solution was investigated using chemical equilibrium models. These models show that for soils with low to moderately low exchangeable bases the soil solution pH is on...

  18. Do Uric Acid Deposits in Zooxanthellae Function as Eye-Spots?

    PubMed Central

    Yamashita, Hiroshi; Kobiyama, Atsushi; Koike, Kazuhiko

    2009-01-01

    The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium) and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100–150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot. PMID:19609449

  19. DISCOVERING THE CAUSES, CONSEQUENCES, AND IMPLICATIONS OF ACID RAIN AND ATMOSPHERIC DEPOSITION

    EPA Science Inventory

    Much has been learned in recent years about air pollution, acid precipitation and atmospheric deposition and their effects on public welfare. There are still unanswered questions about certain aspects of these problems and possible strategies for their solution. Public concern ab...

  20. FIELD COMPARISON OF METHODS FOR THE MEASUREMENT OF CONTRIBUTORS TO ACIDIC DRY DEPOSITION

    EPA Science Inventory

    A field study was conducted to compare methods for sampling and analysis of atmospheric constituents that are important contributors to acidic dry deposition. hree multicomponent samplers were used: the Canadian filter pack (FP), the annular denuder system (ADS), and the transiti...

  1. EFFECTS OF ACIDIC DEPOSITION ON NORTH AMERICAN LAKES: PALAEOLIMNOLOGICAL EVIDENCE FORM DIATOMS AND CHRYSOPHYTES

    EPA Science Inventory

    Analysis of sediment diatom and chrysophyte assemblages is the best technique currently available for inferring past lakewater pH trends, and use of the approach for assessing the ecological effects of acidic deposition is increasing rapidly. s of August 1989, sediment core infer...

  2. ACIDIFICATION AND RECOVERY OF A SPODOSOL BS HORIZON FROM ACIDIC DEPOSITION

    EPA Science Inventory

    A laboratory study was conducted to examine acidification and recovery of a Spodosol Bs horizon from acidic deposition in the Bear Brook Watershed (BBW) in central Maine. echanical vacuum extractor was used to draw solutions through a soil column at three treatments containing 40...

  3. Response of DOC in acid-sensitive Maine lakes to decreasing sulfur deposition (1993 - 2009)

    EPA Science Inventory

    In response to the Clean Air Act Amendments of 1990, sulfur deposition has decreased across the northeastern United States. As a result, sulfate concentrations in lakes and streams have also decreased and many surface waters have become less acidic. Over the same time period, th...

  4. EVALUATING CHANGES IN FOREST CONDITION POTENTIALLY RELATED TO ACIDIC DEPOSITION: AN EXAMPLE USING RED SPRUCE

    EPA Science Inventory

    As a result of concern about forest decline in Europe and the USA, research has been conducted to investigate changes in forest condition that might be associated with acidic deposition and related pollutants (principally ozone). ymptoms of tree decline observed in the field typi...

  5. ANALYTICAL TECHNIQUES FOR MEASURING THE EFFECTS OF ACID DEPOSITION ON COATINGS ON WOOD

    EPA Science Inventory

    Preliminary experiments have been carried out to characterize the potential deleterious effects of acidic deposition on three representative paints: an oil alkyd paint and two acrylic latex formulations. The base polymer latex common to both latex paints was also studied individu...

  6. Precipitation-chemistry measurements from the California Acid Deposition Monitoring Program, 1985-1990

    USGS Publications Warehouse

    Blanchard, Charles L.; Tonnessen, Kathy A.

    1993-01-01

    The configuration of the California Acid Deposition Monitoring Program (CADMP) precipitation network is described and quality assurance results summarized. Comparison of CADMP and the National Acid Deposition Program/National Trends Network (NADP/NTN) data at four parallel sites indicated that mean depth-weighted differences were less than 3 μeq ℓ−1 for all ions, being statistically significant for ammonium, sulfate and hydrogen ion. These apparently small differences were 15–30% of the mean concentrations of ammonium, sulfate and hydrogen ion. Mean depth-weighted concentrations and mass deposition rates for the period 1985–1990 are summarized; the latter were highest either where concentrations or precipitation depths were relatively high.

  7. Electrophoretic deposition and electrochemical behavior of novel graphene oxide-hyaluronic acid-hydroxyapatite nanocomposite coatings

    NASA Astrophysics Data System (ADS)

    Li, Ming; Liu, Qian; Jia, Zhaojun; Xu, Xuchen; Shi, Yuying; Cheng, Yan; Zheng, Yufeng; Xi, Tingfei; Wei, Shicheng

    2013-11-01

    Novel ternary graphene oxide-hyaluronic acid-hydroxyapatite (GO-HY-HA) nanocomposite coatings were prepared on Ti substrate using anodic electrophoretic deposition (EPD). Hyaluronic acid was employed as charging additive and dispersion agent during EPD. The kinetics and mechanism of the deposition, and the microstructure of the coated samples were investigated using scanning electron microscopy, X-ray diffraction, Raman spectrum, thermo-gravimetric analysis, and microscopic Fourier transform infrared analysis. The results showed that the addition of GO sheets into the HY-HA suspensions could increase the deposition rate and inhibit cracks creation and propagation in the coatings. The corrosion resistant of the resulting samples were evaluated using potentiodynamic polarization method in simulated body fluid, and the GO-HY-HA coatings could effectively improve the anti-corrosion property of the Ti substrate.

  8. Laser damage properties of TiO{sub 2}/Al{sub 2}O{sub 3} thin films grown by atomic layer deposition

    SciTech Connect

    Wei Yaowei; Liu Hao; Sheng Ouyang; Liu Zhichao; Chen Songlin; Yang Liming

    2011-08-20

    Research on thin film deposited by atomic layer deposition (ALD) for laser damage resistance is rare. In this paper, it has been used to deposit TiO{sub 2}/Al{sub 2}O{sub 3} films at 110 deg. C and 280 deg. C on fused silica and BK7 substrates. Microstructure of the thin films was investigated by x-ray diffraction. The laser-induced damage threshold (LIDT) of samples was measured by a damage test system. Damage morphology was studied under a Nomarski differential interference contrast microscope and further checked under an atomic force microscope. Multilayers deposited at different temperatures were compared. The results show that the films deposited by ALD had better uniformity and transmission; in this paper, the uniformity is better than 99% over 100 mm {Phi} samples, and the transmission is more than 99.8% at 1064 nm. Deposition temperature affects the deposition rate and the thin film microstructure and further influences the LIDT of the thin films. As to the TiO{sub 2}/Al{sub 2}O{sub 3} films, the LIDTs were 6.73{+-}0.47 J/cm{sup 2} and 6.5{+-}0.46 J/cm{sup 2} at 110 deg. C on fused silica and BK7 substrates, respectively. The LIDTs at 110 deg. C are notably better than 280 deg. C.

  9. Evidence that 3-hydroxy-3-methylglutaric and 3-methylglutaric acids induce DNA damage in rat striatum.

    PubMed

    da Rosa, Mateus Struecker; Scaini, Giselli; Damiani, Adriani Paganini; Longaretti, Luiza Martins; Pereira, Maiara; Seminotti, Bianca; Zapelini, Hugo Galvane; Schuck, Patrícia Fernanda; Streck, Emílio Luiz; de Andrade, Vanessa Moraes; Wajner, Moacir; Leipnitz, Guilhian

    2015-08-01

    3-Hydroxy-3-methylglutaryl-CoA lyase (HL) deficiency is a rare autosomal recessive disorderaffecting the final step of leucine degradation and ketogenesis and biochemically characterized by the predominant accumulation of 3-hydroxy-3-methylglutaric (HMG) and 3-methylglutaric (MGA) acids in biological fluids and tissues of affected patients. Considering that previous studies reported that HMG and MGA have pro oxidant properties, the present study evaluated the ex vivo and in vitro effects of HMG and MGA on frequency and index of DNA damage in cerebral cortex and striatum of young rats. The ex vivo effects of both organic acids on 8-hydroxy-2'-deoxyguanosine (OHdG) levels and their in vitro effects on 2',7'-dichlorofluorescin (DCFH) oxidation and glutathione (GSH) concentrations in rat striatum were also determined. We also investigated the ex vivo effects of both organic acids on 8-hydroxy-2'-deoxyguanosine (OHdG) levels in rat striatum. In the ex vivo experiments, DNA damage was determined in striatum homogenates prepared 30 min after a single intrastriatal administration of HMG or MGA. On the other hand, the in vitro evaluation was performed after an incubation of rat cerebral cortex or striatum homogenates or slices in the presence of HMG or MGA during 1 h at 37 °C. We observed that the intrastriatal administration of HMG and MGA increased the frequency and the index of DNA damage, as well as OHdG staining in rat striatum. We also verified that MGA, but not HMG, increased DNA damage frequency and index in vitro in striatum of rats. In contrast, no alterations were verified in vitro in cerebral cortex. Finally, we found that HMG and MGA increased DCFH oxidation and decreased GSH concentrations in rat striatum. Therefore, it may be presumed that DNA damage provoked by HMG and MGA possibly via reactive species generation is involved, at least in part, in the pathophysiology of brain injury, particularly in the striatum of HL-deficient patients. PMID:25939283

  10. Influence of Deposition Temperature on Optical and Laser-Induced Damage Properties of LaTiO3 Films

    NASA Astrophysics Data System (ADS)

    Su, Junhong; Xu, Junqi; Yang, Chen; Cheng, Yaojin

    2015-08-01

    LaTiO3 films were prepared at room temperature, 60, 140 and 220°C using a thermal vapor deposition technique with an electronic beam gun to investigate the relationship between deposition temperatures and the optical properties of the samples. In the ellipsometric analysis, the corresponding refractive indexes were 1.8993, 1.9123, 1.9197 and 1.9283 at a wavelength of 1064 nm. At the same time, extremely low absorption characteristics of all the samples presented in the visible and IR regions. With the same high-energy testing laser of 200 mJ (about 40 J/cm2) at a wavelength of 1064 nm and a pulse width of 10 ns, the laser-induced damage threshold (LIDT) of the LaTiO3 samples prepared at different temperatures were 15.5, 16.7, 18.5 and 18.2 J/cm2, respectively. This shows that a higher LIDT may be obtained at higher deposition temperatures.

  11. High damage threshold anti-reflectors by physical vapor deposited amorphous fluoropolymer

    SciTech Connect

    Chow, R.; Spragge, M.K.; Loomis, G.E.; Thomas, I.M.; Rainer, F.; Ward, R.L.; Kozlowski, M.R.

    1993-11-01

    High laser-resistant anti-reflective coatings were made from an amorphous fluoropolymer (Teflon AF2400) material by physical vapor deposition. Single layers of Teflon AF2400 were thermally deposited in a vacuum chamber. Refractive index and adhesion of the coatings were determined as a function of deposition rate (2 to 20 {Angstrom}/s), substrate temperature (20 to 200C), and glow-discharge bias potential ({minus}1500 to 1500 V). An anti-reflective coating of an amorphous fluoropolymer (Teflon AF2400) had a laser resistance of > 47 J/cm{sup 2} (1.06 {mu}m, 3-ns pulselength) and is transparent from 200 nm to 1600 nm. The majority of the coatings had a 1.30 refractive index, similar to that of the bulk material. Scanning electron microscopy and preliminary nuclear magnetic resonance observations indicated that morphological changes caused the variations in the refractive index rather than compositional changes. The coatings adhered to fused silica and silicon wafers under normal laboratory handling conditions. Scotch tape with 12.6 gr/mm tension was sufficient to pull off every coating from fused silica substrates.

  12. Suppression of rice methane emission by sulfate deposition in simulated acid rain

    NASA Astrophysics Data System (ADS)

    Gauci, Vincent; Dise, Nancy B.; Howell, Graham; Jenkins, Meaghan E.

    2008-09-01

    Sulfate in acid rain is known to suppress methane (CH4) emissions from natural freshwater wetlands. Here we examine the possibility that CH4 emissions from rice agriculture may be similarly affected by acid rain, a major and increasing pollution problem in Asia. Our findings suggest that acid rain rates of SO42- deposition may help to reduce CH4 emissions from rice agriculture. Emissions from rice plants treated with simulated acid rain at levels of SO42- consistent with the range of deposition in Asia were reduced by 24% during the grain filling and ripening stage of the rice season which accounts for 50% of the overall CH4 that is normally emitted in a rice season. A single application of SO42- at a comparable level reduced CH4 emission by 43%. We hypothesize that the reduction in CH4 emission may be due to a combination of effects. The first mechanism is that the low rates of SO42- may be sufficient to boost yields of rice and, in so doing, may cause a reduction in root exudates to the rhizosphere, a key substrate source for methanogenesis. Decreasing a major substrate source for methanogens is also likely to intensify competition with sulfate-reducing microorganisms for whom prior SO42- limitation had been lifted by the simulated acid rain S deposition.

  13. Amino-acid racemizarion in Quaternary shell deposits at Willapa Bay, Washington

    USGS Publications Warehouse

    Kvenvolden, K.A.; Blunt, D.J.; Clifton, H.E.

    1979-01-01

    Extents of racemization ( d l ratios) of amino acids in fossil Saxidomus giganteus (Deshayes) and Ostrea lurida Carpenter were measured on shell deposits exposed at 21 sites on the east side of Willapa Bay, Washington. Amino acids from Saxidomus show less variability in d Spl ratios and, therefore, are of greater use in correlation and age estimation than are amino acids from Ostrea. Shells of two different ages, about 120,000 ?? 40,000 yr old and about 190,000 ?? 40,000 yr old, are present. These ages correspond to Stages 5 and 7 of the marine isotope record defined by Shackleton and Opdyke in 1973 and hence the shell deposits likely formed during two different high stands of sea level. The stratigraphic record at Willapa Bay is consistent with this interpretation. ?? 1979.

  14. SPECTRAL REFLECTANCE METHOD TO MEASURE ACID DEPOSITION EFFECTS ON BUILDING STONE.

    USGS Publications Warehouse

    Kingston, Marguerite J.; Ager, Cathy M.

    1985-01-01

    As part of the National Acid Precipitation Assessment Program (NAPAP), the U. S. Geological Survey is cooperating with other agencies to test the effects of acid deposition on building stone. A 10-year test-site study has been organized for the purpose of correlating possible stone deterioration with environmental factors. In Summer 1984, slabs of building stone, 3 by 2 by 2 inches, were exposed to the atmosphere at four test sites where the pH of precipitation and other meteorological variables are continuously monitored. This paper examines the development of one experimental technique used in this study - the application of diffuse spectral reflectance methods for laboratory and in situ measurement of those properties of stone which may be affected by acid deposition.

  15. Effects of Folic Acid on Secretases Involved in Aβ Deposition in APP/PS1 Mice.

    PubMed

    Tian, Tian; Bai, Dong; Li, Wen; Huang, Guo-Wei; Liu, Huan

    2016-01-01

    Alzheimer's disease (AD) is the most common type of dementia. Amyloid-β protein (Aβ) is identified as the core protein of neuritic plaques. Aβ is generated by the sequential cleavage of the amyloid precursor protein (APP) via the APP cleaving enzyme (α-secretase, or β-secretase) and γ-secretase. Previous studies indicated that folate deficiency elevated Aβ deposition in APP/PS1 mice, and this rise was prevented by folic acid. In the present study, we aimed to investigate whether folic acid could influence the generation of Aβ by regulating α-, β-, and γ-secretase. Herein, we demonstrated that folic acid reduced the deposition of Aβ42 in APP/PS1 mice brain by decreasing the mRNA and protein expressions of β-secretase [beta-site APP-cleaving enzyme 1 (BACE1)] and γ-secretase complex catalytic component-presenilin 1 (PS1)-in APP/PS1 mice brain. Meanwhile, folic acid increased the levels of ADAM9 and ADAM10, which are important α-secretases in ADAM (a disintegrin and metalloprotease) family. However, folic acid has no impact on the protein expression of nicastrin (Nct), another component of γ-secretase complex. Moreover, folic acid regulated the expression of miR-126-3p and miR-339-5p, which target ADAM9 and BACE1, respectively. Taken together, the effect of folic acid on Aβ deposition may relate to making APP metabolism through non-amyloidogenic pathway by decreasing β-secretase and increasing α-secretase. MicroRNA (miRNA) may involve in the regulation mechanism of folic acid on secretase expression. PMID:27618097

  16. Contemporaneous deposition of phyllosilicates and sulfates: Using Australian acidic saline lake deposits to describe geochemical variability on Mars

    USGS Publications Warehouse

    Baldridge, A.M.; Hook, S.J.; Crowley, J.K.; Marion, G.M.; Kargel, J.S.; Michalski, J.L.; Thomson, B.J.; de Souza, Filho C.R.; Bridges, N.T.; Brown, A.J.

    2009-01-01

    Studies of the origin of the Martian sulfate and phyllosilicate deposits have led to the hypothesis that there was a marked, global-scale change in the Mars environment from circum-neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to Hesperian. However, terrestrial studies suggest that two different geochemical systems need not be invoked to explain such geochemical variation.Western Australian acidic playa lakes have large pH differences separated vertically and laterally by only a few tens of meters, demonstrating how highly variable chemistries can coexist over short distances in natural environments. We suggest diverse and variable Martian aqueous environments where the coetaneous formation of phyllosilicates and sulfates at the Australian sites are analogs for regions where phyllosilicates and sulfates coexist on Mars. In these systems, Fe and alkali earth phyllosilicates represent deep facies associated with upwelling neutral to alkaline groundwater, whereas aluminous phyllosilicates and sulfates represent near-surface evaporitic facies formed from more acidic brines. Copyright 2009 by the American Geophysical Union.

  17. Use of stream chemistry for monitoring acidic deposition effects in the Adirondack region of New York

    USGS Publications Warehouse

    Lawrence, G.B.; Momen, B.; Roy, K.M.

    2004-01-01

    Acid-neutralizing capacity (ANC) and pH were measured weekly from October 1991 through September 2001 in three streams in the western Adirondack Mountain region of New York to identify trends in stream chemistry that might be related to changes in acidic deposition. A decreasing trend in atmospheric deposition of SO42- was observed within the region over the 10-yr period, although most of the decrease occurred between 1991 and 1995. Both ANC and pH were inversely related to flow in all streams; therefore, a trend analysis was conducted on (i) the measured values of ANC and pH and (ii) the residuals of the concentration-discharge relations. In Buck Creek, ANC increased significantly (p 0.10). In Bald Mountain Brook, ANC and residuals of ANC increased significantly (p < 0.01), although the trend was diatonic-a distinct decrease from 1991 to 1996 was followed by a distinct increase from 1996 to 2001. In Fly Pond outlet, ANC and residuals of ANC increased over the study period (p < 0.01), although the trend of the residuals resulted largely from an abrupt increase in 1997. In general, the trends observed in the three streams are similar to results presented for Adirondack lakes in a previous study, and are consistent with the declining trend in atmospheric deposition for this region, although the observed trends in ANC and pH in streams could not be directly attributed to the trends in acidic deposition.

  18. The Tracking and Analysis Framework (TAF): A tool for the integrated assessment of acid deposition

    SciTech Connect

    Bloyd, C.N.; Henrion, M.; Marnicio, R.J.

    1995-06-01

    A major challenge that has faced policy makers concerned with acid deposition is obtaining an integrated view of the underlying science related to acid deposition. In response to this challenge, the US Department of Energy is sponsoring the development of an integrated Tracking and Analysis Framework (TAF) which links together the key acid deposition components of emissions, air transport, atmospheric deposition, and aquatic effects in a single modeling structure. The goal of TAF is to integrate credible models of the scientific and technical issues into an assessment framework that can directly address key policy issues, and in doing so act as a bridge between science and policy. Key objectives of TAF are to support coordination and communication among scientific researchers; to support communications with policy makers, and to provide rapid response for analyzing newly emerging policy issues; and to provide guidance for prioritizing research programs. This paper briefly describes how TAF was formulated to meet those objectives and the underlying principals which form the basis for its development.

  19. Effects of acid deposition on calcium nutrition and health of Southern Appalachian spruce fir forests

    SciTech Connect

    McLaughlin, S.B.; Wullschleger, S.; Stone, A.; Wimmer, R.; Joslin, J.D.

    1995-02-01

    The role of acid deposition in the health of spruce fir forests in the Southern Appalachian Mountains has been investigated by a wide variety of experimental approaches during the past 10 years. These studies have proceeded from initial dendroecological documentation of altered growth patterns of mature trees to increasingly more focused ecophysiological research on the causes and characteristics of changes in system function associated with increased acidic deposition. Field studies across gradients in deposition and soil chemistry have been located on four mountains spanning 85 km of latitude within the Southern Appalachians. The conclusion that calcium nutrition is an important component regulating health of red spruce in the Southern Appalachians and that acid deposition significantly reduces calcium availability in several ways has emerged as a consistent result from multiple lines or research. These have included analysis of trends in wood chemistry, soil solution chemistry, foliar nutrition, gas exchange physiology, root histochemistry, and controlled laboratory and field studies in which acid deposition and/or calcium nutrition has been manipulated and growth and nutritional status of saplings or mature red spruce trees measured. This earlier research has led us to investigate the broader implications and consequences of calcium deficiency for changing resistance of spruce-fir forests to natural stresses. Current research is exploring possible relationships between altered calcium nutrition and shifts in response of Fraser fir to insect attack by the balsam wooly adelgid. In addition, changes in wood ultrastructural properties in relation to altered wood chemistry is being examined to evaluate its possible role in canopy deterioration, under wind and ice stresses typical of high elevation forests.

  20. Acid deposition sensitivity map of the Southern Appalachian Assessment area; Virginia, North Carolina, South Carolina, Tennessee, Georgia, and Alabama

    USGS Publications Warehouse

    Pepper, John D.; Grosz, Andrew E.; Kress, Thomas H.; Collins, Thomas K.; Kappesser, Gary B.; Huber, Cindy M.; Webb, James R.

    1995-01-01

    Project Summary: The following digital product represents the Acid Deposition Sensitivity of the Southern Appalachian Assessment Area. Areas having various susceptibilities to acid deposition from air pollution are designated on a three tier ranking in the region of the Southern Appalachian Assessment (SAA). The assessment is being conducted by Federal agencies that are members of the Southern Appalachian Man and Biosphere (SAMAB) Cooperative. Sensitivities to acid deposition, ranked high, medium, and low are assigned on the basis of bedrock compositions and their associated soils, and their capacities to neutralize acid precipitation.

  1. Intraneuronal Amyloid β Accumulation and Oxidative Damage to Nucleic Acids in Alzheimer Disease

    PubMed Central

    Nunomura, Akihiko; Tamaoki, Toshio; Tanaka, Koich; Motohashi, Nobutaka; Nakamura, Masao; Hayashi, Takaaki; Yamaguchi, Haruyasu; Shimohama, Shun; Lee, Hyoung-gon; Zhu, Xiongwei; Smith, Mark A.; Perry, George

    2010-01-01

    An in situ approach was used to identify amyloid-β (Aβ) accumulation and oxidative damage to nucleic acids in postmortem brain tissue of the hippocampal formation from subjects with Alzheimer disease. When carboxyl-terminal specific antibodies directed against Aβ40 and Aβ42 were used for immunocytochemical analyses, Aβ42 was especially apparent within the neuronal cytoplasm, at sites not detected by the antibody specific to Aβ-oligomer. In comparison to the Aβ42-positive neurons, neurons bearing oxidative damage to nucleic acids were more widely distributed in the hippocampus. Comparative density measurements of the immunoreactivity revealed that levels of intraneuronal Aβ42 were inversely correlated with levels of intraneuronal 8-hydroxyguanosine, an oxidized nucleoside (r = − 0.61, p < 0.02). Together with recent evidence that the Aβ peptide can act as an antioxidant, these results suggest that intraneuronal accumulation of non-oligomeric Aβ may be a compensatory response in neurons to oxidative stress in Alzheimer disease. PMID:20034567

  2. Damaged Cave Deposits in Haifa: Evidence for Destructive Earthquakes from the Carmel Fault

    NASA Astrophysics Data System (ADS)

    Braun, Y.; Bar-Matthews, M.; Ayalon, A.; Kagan, E.; Agnon, A.

    2007-12-01

    A study conducted in a cave located in the Mount Carmel region (Denya Cave), shows that broken speleothems can provide evidence for damage related to ancient earthquakes on the Carmel fault. Following the work of Kagan et al. (2005) in the Judean Hills, in which accurate 234U/ 230Th ages of collapsed speleothems were consistent with independent evidence for strong earthquakes, we present here initial results from the Denya Cave. Mt. Carmel is a manifestation of tectonic movements in the north of Israel. It is a continental uplift of more than 800m above sea level. It is defined by the northwestern to north-northwestern trending Carmel fault, a branch of the Dead Sea transform system, and continues into the Mediterranean continental shelf (Hofstetter et al., 1989). The fault has been active since the Miocene and activity during the Pleistocene is evident, and yet very little is known about the extent of its seismic activity during the Quaternary (Gluck, 2002). The region of Mt. Carmel features abundant karst , which can be used in a comprehensive paleo-seismological study of the Carmel fault . The Denya cave is situated on the southern side of the mountain on a spur sloping to the west from the summit of Mount Carmel, toward the town of Tirat Ha-Carmel. Work in Denya Cave, up to this stage includes detailed mapping and initial collection of speleothem samples suspected of being seismites (broken or deformed speleothems that could result from seismic activity), and their dating using the 234U/ 230Th method. Measurements for dating are conducted on the Multiple Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICP-MS) in the Geological Survey of Israel. The age of one seismic event, as evident from three damaged stalagmite samples, is ca. 11ka. This age was determined for post- and pre-collapse laminae. Five ages of ca. 10ka were obtained from other seismites and it is not clear yet whether they represent the same event or a subsequent one. A cluster of older

  3. Giant uranium deposits formed from exceptionally uranium-rich acidic brines

    NASA Astrophysics Data System (ADS)

    Richard, Antonin; Rozsypal, Christophe; Mercadier, Julien; Banks, David A.; Cuney, Michel; Boiron, Marie-Christine; Cathelineau, Michel

    2012-02-01

    Giant uranium deposits were formed during the Mesoproterozoic era, 1.6-1.0 Gyr ago, in both Canada and Australia. The deposits are thought to have formed from large-scale circulation of brines at temperatures of 120-200 °C that percolated between sedimentary basins and underlying crystalline basement rocks. However, the precise conditions for transport of the uranium in these brines are poorly understood. Here we use mass spectrometry to analyse the uranium content of brines preserved in naturally occurring fluid inclusions in ore deposits from the Athabasca Basin, Canada. We measure concentrations of uranium in the range 1.0×10-6-2.8×10-3moll-1. These concentrations are three orders of magnitude above any other common crustal fluids. Experimentally, we measure the solubility of uranium as a function of NaCl content and pH, in mixtures that are analogous to ore-forming brines at 155°C. To account for the high uranium content observed in the Athabasca deposits, we find that the brines must have been acidic, with a pH between 2.5 and 4.5. Our results strongly suggest that the world's richest uranium deposits formed from highly concentrated uranium-bearing acidic brines. We conclude that these conditions are a necessary requirement for the formation of giant uranium deposits in relatively short periods of time of about 0.1-1 Myr, similar to other world-class deposits of lead-zinc and gold.

  4. Protection against radiation-induced DNA damage by amino acids: a DFT study.

    PubMed

    Jena, N R; Mishra, P C; Suhai, S

    2009-04-23

    Direct and indirect radiation-induced DNA damage is associated with the formation of radical cations (G(+)) and radical anions (G(-)) of guanine, respectively. Deprotonation of G(+) and dehydrogenation of G(-) generate guanine neutral radical [G(-H)] and guanine anion [G(-H)(-)], respectively. These products are of worrisome concern, as they are involved in reactions that are related to certain lethal diseases. It has been observed that guanyl radicals can be repaired by amino acids having strong reducing properties that are believed to be the residues of DNA-bound proteins such as histones. As a result, repair of G(-H) and G(-H)(-) by the amino acids cysteine and tyrosine has been studied here in detail by density functional theory in both the gas phase and aqueous medium using the polarized continuum and Onsager solvation models of self-consistent reaction field theory. Solvation in aqueous medium using three explicit water molecules was also studied. Four equivalent tautomers of each the above radical and anion that will be formed through proton and hydrogen loss from all of the nitrogen centers of guanine radical cation and guanine radical anion, respectively, were considered in the present study. It was found that in both the gas phase and aqueous medium, normal guanine can be retrieved from its radical-damaged form by a hydrogen-atom-transfer (HT) mechanism. Normal guanine can also be retrieved from its anionic damaged form in both the gas phase and aqueous medium through a two-electron-coupled proton-transfer (TECPT) mechanism or a one-step hydrogen-atom- and electron-transfer (OSHET) mechanism. The present results are discussed in light of the experimental findings. PMID:19334703

  5. A Study of Effects of Acid Deposition on Pine Forest Ecosystem in Southwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Li, F.; Lv, Z.; Song, W.; Yang, S.

    2013-12-01

    We used a long-term soil acidification model (LTSAM) and a terrestrial biogeochemical model (CENTURY) coupled to simulate the effects of acid deposition on pine forest ecosystem in southwestern China, based on indoor experiment results of aluminum toxicity to individual plant growth. The results of indoor aluminum experiments show that high aluminum concentration may restrict the plant growth and the acidic condition may aggravate it. The behavior of restriction of plant growth includes decreases of pine seedling biomass, root elongation and the sorption of soil cations (e.g. Ca2+, Mg2+, Na+ and K+). The model simulation results about soil chemistry show that, as acid deposition increases more, the pH value decreases faster, the soil aluminum ion concentration increase more rapidly, and the nutrition ions in soil solution decrease more quickly. The increased acid deposition also has negative impacts on the forest ecosystem according to the biogeochemical model simulation, for example, decreases of vegetation biomass, net primary productivity (NPP) and net CO2 uptake. Furthermore, the decrease of plant biomass will result in the decrease of the soil organic carbon content for the limited decomposition material supply.

  6. Influence of alkaline suspended particles on the chemical composition of acid deposition in Kaohsiung City, Taiwan

    SciTech Connect

    Yuan, C.S.; Lin, Z.J.; Wu, M.Y.; Liu, J.I.; Yuan, C.

    1998-12-31

    This study investigated the influence of alkaline suspended particles on the chemical composition of acid deposition both temporally and spatially in Kaohsiung metropolitan area in Taiwan. During the period of January--December, 1996, both wet and dry deposition samples were collected by automatic acid precipitation samplers at six sampling sites which covered the entire metropolitan area. Major cations (NH{sub 4}{sup +}, K{sup +}, Na{sup +}, Ca{sup +2}, and Mg{sup +2}) and anions (F{sup {minus}}, Cl{sup {minus}}, NO{sub 3}{sup {minus}}, and SO{sub 4}{sup {minus}2}) of acid deposition samples were analyzed in a central laboratory, while the pH value and conductivity of rainwater samples were measured in situ. Results from chemical analysis indicated that Ca{sup +2} was the most abundant cation in acid deposition samples. Major cations were Ca{sup +2} and NH{sub 4}{sup +}, while major anions were SO{sub 4}{sup {minus}2} and NO{sub 3}{sup {minus}}. This study also revealed that the pH value, suspended solids, Ca{sup +2}, and NH{sub 4}{sup +} of rainwater decreased with rainy time in a sequential rainwater sampling process. It was estimated that approximately 80% of suspended particles could be washed out by rain droplets in the first hour of raining process. Therefore, alkaline suspended particles in the atmosphere played an very important role on the chemical composition of acid precipitation in Kaohsiung metropolitan area in Taiwan.

  7. Soil calcium status and the response of stream chemistry to changing acidic deposition rates

    USGS Publications Warehouse

    Lawrence, G.B.; David, M.B.; Lovett, Gary M.; Murdoch, Peter S.; Burns, Douglas A.; Stoddard, J.L.; Baldigo, Barry P.; Porter, J.H.; Thompson, A.W.

    1999-01-01

    Despite a decreasing trend in acidic deposition rates over the past two to three decades, acidified surface waters in the northeastern United States have shown minimal changes. Depletion of soil Ca pools has been suggested as a cause, although changes in soil Ca pools have not been directly related to long-term records of stream chemistry. To investigate this problem, a comprehensive watershed study was conducted in the Neversink River Basin, in the Catskill Mountains of New York, during 1991-1996. Spatial variations of atmospheric deposition, soil chemistry, and stream chemistry were evaluated over an elevation range of 817-1234 m to determine whether these factors exhibited elevational patterns. An increase in atmospheric deposition of SO4 with increasing elevation corresponded with upslope decreases of exchangeable soil base concentrations and acid-neutralizing capacity of stream water. Exchangeable base concentrations in homogeneous soil incubated within the soil profile for one year also decreased with increasing elevation. An elevational gradient in precipitation was not observed, and effects of a temperature gradient on soil properties were not detected. Laboratory leaching experiments with soils from this watershed showed that (1) concentrations of Ca in leachate increased as the concentrations of acid anions in added solution increased, and (2) the slope of this relationship was positively correlated with base saturation. Field and laboratory soil analyses are consistent with the interpretation that decreasing trends in acid-neutralizing capacity in stream water in the Neversink Basin, dating back to 1984, are the result of decreases in soil base saturation caused by acidic deposition.

  8. Deposition kinetics and characterization of stable ionomers from hexamethyldisiloxane and methacrylic acid by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Urstöger, Georg; Resel, Roland; Koller, Georg; Coclite, Anna Maria

    2016-04-01

    A novel ionomer of hexamethyldisiloxane and methacrylic acid was synthesized by plasma enhanced chemical vapor deposition (PECVD). The PECVD process, being solventless, allows mixing of monomers with very different solubilities, and for polymers formed at high deposition rates and with high structural stability (due to the high number of cross-links and covalent bonding to the substrate) to be obtained. A kinetic study over a large set of parameters was run with the aim of determining the optimal conditions for high stability and proton conductivity of the polymer layer. Copolymers with good stability over 6 months' time in air and water were obtained, as demonstrated by ellipsometry, X-Ray reflectivity, and FT-IR spectroscopy. Stable coatings showed also proton conductivity as high as 1.1 ± 0.1 mS cm-1. Chemical analysis showed that due to the high molecular weight of the chosen precursors, it was possible to keep the plasma energy-input-per-mass low. This allowed limited precursor fragmentation and the functional groups of both monomers to be retained during the plasma polymerization.

  9. Anthropogenic Oxidation of Seafloor Massive Sulfide (SMS) deposits: Implications for Localized Seafloor Acid Generation

    NASA Astrophysics Data System (ADS)

    Bilenker, L.; Romano, G. Y.; Mckibben, M. A.

    2011-12-01

    A rapid increase in the price of transition metals in recent years has piqued interest in deep sea in situ mining of seafloor massive sulfide (SMS) deposits. There are important unanswered questions about the potential environmental effects of seafloor mining, particularly localized sulfuric acid generation. Currently there is a paucity of data on the oxidation kinetics of sulfide minerals in seawater. Seafloor massive sulfides oxidize rapidly via irreversible, acid-producing reactions. The oxidation kinetics of these minerals need to be quantified to estimate the significance of acid production. Laboratory experiments have been performed to evaluate the effects of pH, temperature, oxidant concentration, and mineral surface area on the rate of oxidation of chalcopyrite (CuFeS2) and pyrrhotite (Fe1-xS) in seawater. Temperature controlled circulation baths, Teflon reaction vessels, synthetic seawater, and pure, hand sorted natural sulfide mineral crystals are used in experiments. Both batch and flow-through reactor methods are employed. Reaction products are analyzed using ICP-MS. The rate law is expressed as follows: R = k (MO2,aq)a(MH+)b where R is the specific mineral oxidation rate (moles/m2/sec), k is the rate constant (a function of temperature), and a and b are reaction orders for molar aqueous species' concentrations (M). The initial rate method is used to determine the reaction order of each variable. Chalcopyrite and pyrrhotite are being studied because as the slowest- and fastest-oxidizing of the common sulfide minerals found in SMS deposits, they bound the range of rates seen in seafloor settings and can be used to place lower and upper limits on abiotic rates of metal release and sulfuric acid production. Experiments to date indicate an oxidation rate of pyrrhotite several times faster than that of chalcopyrite. The rate laws, when incorporated into reactive-transport computer codes, will enable the prediction of localized anthropogenic sulfuric acid

  10. Physicochemical basis for dilated intercellular spaces in non-erosive acid-damaged rabbit esophageal epithelium.

    PubMed

    Tobey, N A; Gambling, T M; Vanegas, X C; Carson, J L; Orlando, R C

    2008-01-01

    Dilated intercellular spaces (DIS) within esophageal epithelium (EE) is a histopathologic feature of non-erosive reflux disease and early lesion in acid-damaged rabbit EE associated with increased paracellular permeability. Its cause remains unknown, but the lesion's morphology suggests a significant fluid shift into the intercellular spaces (ICS). Since water follows osmotic forces and consequently ion movements, we explored the role of active (ion) transport and ion gradients in its pathogenesis. This was done by quantifying the effect of inhibited active transport and altered ion gradients on electrical resistance (R(T)) and ICS diameter in acid-exposed Ussing-chambered rabbit EE. Compared with normal Ringer, pH 7.5, 30 minutes of luminal HCl (100 mmol/L), pH 1.1, increased permeability (R(T): +5 +/- 4% vs-52 +/- 4%) and ICS diameter (0.25 +/- 0.01 microm vs 0.42 +/- 0.02 microm), but had no effect on cell morphology or diameter. Ouabain pretreatment significantly reduced active transport but had no effect on the acid-induced changes. However, negating the chloride gradient created by luminal HCl either by adding choline chloride, 100 mmol/L, serosally or by replacing luminal HCl, pH 1.1, with luminal H(2)SO(4), pH 1.1, prevented the development of DIS while maintaining the increase in permeability. DIS was also prevented in the presence of a 100 mmol/L (choline) chloride gradient by luminal exposure at neutral pH. DIS in HCl-damaged EE is caused by an H(+)-induced increase in epithelial permeability; this enables Cl(-) to diffuse along its gradient into the ICS, creating an osmotic force for water movement into and (hydrostatic) dilation of the ICS. PMID:18522636

  11. Investigation of hair dye deposition, hair color loss, and hair damage during multiple oxidative dyeing and shampooing cycles.

    PubMed

    Zhang, Guojin; McMullen, Roger L; Kulcsar, Lidia

    2016-01-01

    Color fastness is a major concern for consumers and manufacturers of oxidative hair dye products. Hair dye loss results from multiple wash cycles in which the hair dye is dissolved by water and leaches from the hair shaft. In this study, we carried out a series of measurements to help us better understand the kinetics of the leaching process and pathways associated with its escape from the fiber. Hair dye leaching kinetics was measured by suspending hair in a dissolution apparatus and monitoring the dye concentration in solution (leached dye) with an ultraviolet-visible spectrophotometer. The physical state of dye deposited in hair fibers was evaluated by a reflectance light microscopy technique, based on image stacking, allowing enhanced depth of field imaging. The dye distribution within the fiber was monitored by infrared spectroscopic imaging of hair fiber cross sections. Damage to the ultrafine structure of the hair cuticle (surface, endocuticle, and cell membrane complex) and cortex (cell membrane complex) was determined in hair cross sections and on the hair fiber surface with atomic force microscopy. Using differential scanning calorimetry, we investigated how consecutive coloring and leaching processes affect the internal proteins of hair. Further, to probe the surface properties of hair we utilized contact angle measurements. This study was conducted on both pigmented and nonpigmented hair to gain insight into the influence of melanin on the hair dye deposition and leaching processes. Both types of hair were colored utilizing a commercial oxidative hair dye product based on pyrazole chemistry. PMID:27319056

  12. Regional relationships between geomorphic/hydrologic parameters and surface water chemistry relative to acidic deposition

    SciTech Connect

    Rochelle, B.P.; Liff, C.I.; Campbell, W.G.; Cassell, D.L.; Church, M.R.

    1989-01-01

    The authors determined geomorphic and hydrologic parameters for 144 forested, lake watersheds in the Northeast (NE) of the United States based primarily on measurements from topographic maps. These parameters were used to test for relationships with selected surface water chemistry relevant to acidic deposition. Analyses were conducted on regional and subregional scales delineated based on soils, land use, physiography, total sulfur deposition and statistical clustering of selected geomorphic/hydrologic parameters. Significant relationships were found among the geomorphic/hydrologic parameters and the surface water chemistry for the NE. Elevation had the most significant relationship with surface water chemistry, particularly in the mountainous areas of the NE. Other factors occurring consistently as significant predictors of surface water chemistry were maximum relief, relief ratio, runoff, and estimates of basin elongation. Results suggest that elevational parameters might be surrogates for other watershed characteristics, such as soils or spatial deposition patterns.

  13. Inkjet deposition of itraconazole onto poly(glycolic acid) microneedle arrays.

    PubMed

    Boehm, Ryan D; Jaipan, Panupong; Skoog, Shelby A; Stafslien, Shane; VanderWal, Lyndsi; Narayan, Roger J

    2016-03-01

    Poly(glycolic acid) microneedle arrays were fabricated using a drawing lithography process; these arrays were modified with a drug release agent and an antifungal agent by piezoelectric inkjet printing. Coatings containing poly(methyl vinyl ether-co-maleic anhydride), a water-soluble drug release layer, and itraconazole (an antifungal agent), were applied to the microneedles by piezoelectric inkjet printing. Microscopic evaluation of the microneedles indicated that the modified microneedles contained the piezoelectric inkjet printing-deposited agents and that the surface coatings were released in porcine skin. Energy dispersive x-ray spectrometry aided in confirmation that the piezoelectric inkjet printing-deposited agents were successfully applied to the desired target areas of the microneedle surface. Fourier transform infrared spectroscopy was used to confirm the presence of the component materials in the piezoelectric inkjet printing-deposited material. Itraconazole-modified microneedle arrays incubated with agar plates containing Candida albicans cultures showed zones of growth inhibition. PMID:26869165

  14. Modeling wet deposition of acid substances over the PRD region in China

    NASA Astrophysics Data System (ADS)

    Lu, Xingcheng; Fung, Jimmy Chi Hung; Wu, Dongwei

    2015-12-01

    The Pearl River Delta (PRD) region in southern China has suffered heavily from acid rain in the last 10 years due to the anthropogenic emission of sulfur dioxide and nitrogen dioxide. Several measurement-based studies about this issue have been conducted to analyze the chemical composition of precipitation in this area. However, no detailed, high resolution numerical simulation regarding this topic has ever been done in this region. In this study, the WRF-SMOKE-CMAQ system was applied to simulate the wet deposition of acid substances (SO42- and NO3-) in the PRD region from 2009 to 2011 with a resolution of 3 km. The simulation output agreed well with the observation data. Our results showed that Guangzhou was the city most affected by acid rain in this region. The ratio of non-sea-salt sulfate to nitrate indicated that the acid rain in this region belonged to the sulfate-nitrate mixed type. The source apportionment result suggests that point source and super regional source are the ones that contribute the pollutants most in the rain water over PRD Region. The sulfate and nitrate input to some reservoirs via wet deposition was also estimated based on the model simulation. Our results suggest that further cross-city cooperation and emission reduction are needed to further curb acid rain in this region.

  15. The effects of climate change on the nitrogen cycle and acid deposition

    SciTech Connect

    Penner, J.E.; Walton, J.J. ); Graboske, B.C. )

    1990-09-01

    Increases in greenhouse gases are expected to lead to a number of changes to the atmosphere which may impact regional and global chemical cycles. With the increasing awareness of climate change and the possibility of global chemical changes to the atmosphere, it becomes important to ask whether these changes to global climate and chemical cycles might benefit or hinder control programs aimed at reducing acid deposition. In the following, we review several possible changes to climate that may be expected to impact the global cycle of reactive nitrogen. We then use our global model of the reactive nitrogen cycle to estimate the effects of several of the more important changes on the continental-scale deposition of nitric acid. 7 refs., 1 tab.

  16. Modeling the contribution of soil fauna to litter decomposition influenced by acidic deposition

    SciTech Connect

    Cai, B.; Loucks, O.L; Kuperman, R. Argonne National Lab., IL )

    1993-06-01

    The effect of acidic deposition on soil pH and therefore on soil invertebrates and litter decomposition is being investigated in oak-hickory forests across a three-state, midwest, pollution gradient. The role of soil invertebrates has been assessed previously through the use of feeding, assimilation and respiratory rates. These energetic parameters depend strongly on the form of the allometric equations which have been improved here by incorporating uncertainties in body and population size. Results show that changes in reproduction and turnover dynamics of soil invertebrates (particularly of earthworms) due to acid-induced changes in soil pH explains observed patterns in litter depth.

  17. Analysis of potential combustion source impacts on acid deposition using an independently derived inventory. Volume I

    SciTech Connect

    Not Available

    1983-12-01

    This project had three major objectives. The first objective was to develop a fossil fuel combustion source inventory (NO/sub x/, SO/sub x/, and hydrocarbon emissions) that would be relatively easy to use and update for analyzing the impact of combustion emissions on acid deposition in the eastern United States. The second objective of the project was to use the inventory data as a basis for selection of a number of areas that, by virtue of their importance in the acid rain issue, could be further studied to assess the impact of local and intraregional combustion sources. The third objective was to conduct an analysis of wet deposition monitoring data in the areas under study, along with pertinent physical characteristics, meteorological conditions, and emission patterns of these areas, to investigate probable relationships between local and intraregional combustion sources and the deposition of acidic material. The combustion source emissions inventory has been developed for the eastern United States. It characterizes all important area sources and point sources on a county-by-county basis. Its design provides flexibility and simplicity and makes it uniquely useful in overall analysis of emission patterns in the eastern United States. Three regions with basically different emission patterns have been identified and characterized. The statistical analysis of wet deposition monitoring data in conjunction with emission patterns, wind direction, and topography has produced consistent results for each study area and has demonstrated that the wet deposition in each area reflects the characteristics of the localized area around the monitoring sites (typically 50 to 150 miles). 8 references, 28 figures, 39 tables.

  18. Sodium arsenate induce changes in fatty acids profiles and oxidative damage in kidney of rats.

    PubMed

    Kharroubi, Wafa; Dhibi, Madiha; Mekni, Manel; Haouas, Zohra; Chreif, Imed; Neffati, Fadoua; Hammami, Mohamed; Sakly, Rachid

    2014-10-01

    Six groups of rats (n = 10 per group) were exposed to 1 and 10 mg/l of sodium arsenate for 45 and 90 days. Kidneys from treated groups exposed to arsenic showed higher levels of trans isomers of oleic and linoleic acids as trans C181n-9, trans C18:1n-11, and trans C18:2n-6 isomers. However, a significant decrease in eicosenoic (C20:1n-9) and arachidonic (C20:4n-6) acids were observed in treated rats. Moreover, the "Δ5 desaturase index" and the saturated/polyunsaturated fatty acids ratio were increased. There was a significant increase in the level of malondialdehyde at 10 mg/l of treatment and in the amount of conjugated dienes after 90 days (p < 0.05). Significant kidney damage was observed at 10 mg/l by increase of plasma marker enzymes. Histological studies on the ultrastructure changes of kidney supported the toxic effect of arsenate exposure. Arsenate intoxication activates significantly the superoxide dismutase at 10 mg/l for 90 days, whereas the catalase activity was markedly inhibited in all treated groups (p < 0.05). In addition, glutathione peroxidase activity was significantly increased at 45 days and dramatically declined after 90 days at 10 mg/l (p < 0.05). A significant increase in the level of glutathione was marked for the groups treated for 45 and 90 days at 1 mg/l followed by a significant decrease for rats exposed to 10 mg/l for 90 days. An increase in the level of protein carbonyl was observed in all treated groups (p < 0.05). In conclusion, the present study provides evidence for a direct effect of arsenate on fatty acid (FA) metabolism which concerns the synthesis pathway of n-6 polyunsaturated fatty acids and leads to an increase in the trans FAs isomers. Therefore, FA-induced arsenate kidney damage could contribute to trigger kidney cancer. PMID:24920263

  19. Dry deposition and heavy acid loading in the vicinity of Masaya Volcano, a major sulfur and chlorine source in Nicaragua.

    PubMed

    Delmelle, P; Stix, J; Bourque, C P; Baxter, P J; Garcia-Alvarez, J; Barquero, J

    2001-04-01

    Certain volcanoes constitute the world's largest sources of SO2, HCl, and HF emissions and contribute significantly to regional acid deposition. However, the impact of volcanic acid emissions to nearby ecosystems remain poorly documented. In this paper, the spatial pattern of acid dry depositions was monitored within 44 km of Masaya Volcano, Nicaragua, with a network of sulfation plates. Measured SO2 deposition rates were <2-791 mg m(-2) day(-1). The plates also collected the dry deposition of HCI at rates of <1-297 mg m(-2) day(-1). A similar deposition velocity Vd (gas transfer) of 1.6 +/- 0.8 cm/s was calculated for SO2 and HCl above the plate surfaces. Quantities of SO2 and HCI deposited daily within the area surveyed amounted to 1.5 x 10(8) g and 5.7 x 10(7) g, respectively, which correspond to about 10% of the total SO2 and HCl released by the volcano. These depositions may generate an equivalent hydrogen flux ranging from <1 to 30 mg m(-2) day(-1). Our results demonstrate that volcano emissions can dramatically affect acid deposition downwind and in turn cause extreme acid loading of the local ecosystems. This study opens exciting prospects for investigating the sensivity of volcanic ash soils to acid inputs. PMID:11348058

  20. Corrosion damage of the surface of high-speed tool steel in acid-inhibitor pickling

    SciTech Connect

    Mindyuk, A.K.; Sholok, V.I.; Shvets, V.V. Gural', V.M.

    1988-01-01

    Profilograms were recorded of the surface of 20-mm-diameter 1.5-mm-thick specimens prepared from hardened and tempered R6M5 high-speed tool steel (62 HRC) and also of similar specimens subjected to the action of pure hydrochloric acid etching solution and of the same solutions with additions of KhOSP-10, KhOSP-10D, and urotropin inhibitors at 30, 60, and 90/sup 0/C for 4.0, 2.0, and 0.5 h, respectively. The analysis of corrosion damage and determination of the surface finish of the steel made it possible to develop the optimum method of acid-inhibitor pickling specifying the addition to the acid of 1.5 g/liter KhOSP-10 inhibitor and a temperature of 30/sup 0/C. This suppressed the corrosion rate, hydrogen impregnation and embrittlement, decarburization of the steel, and sensitivity to crack formation, and reduced the number of scrapped parts.

  1. The effects of acidic deposition on streams in the Appalachian Mountain and Piedmont region of the mid-Atlantic United States

    SciTech Connect

    Herlihy, A.T.; Kaufman, P.R. ); Church, M.R.; Wigington, P.J. Jr. ); Webb, J.R. ); Sale, M.J. )

    1993-08-01

    Streams in the Appalachian Mountain area of the mid-Atlantic receive some of the largest acidic deposition loadings of any region of the US. A synthesis of the survey data from the mid-Appalachians yields a consistent picture of the acid base status of streams. Acidic streams, and streams with very low acid neutralizing capacity (ANC), are almost all located in small (<20 km[sup 2]), upland, forested catchments in areas of base-poor bedrock. In the subpopulation in the mid-Appalachian area, data from various local surveys show that 6-27% of the streams are acidic, and about 25-50% have ANC less than 50 [mu]eq L[sup [minus]1]. After excluding streams with acid mine drainage, National Stream Survey estimates for the whole region show that there are 2330 km of acidic streams and 7500 km of streams with ANC less than 50 [mu]eq L[sup [minus]1]. Many of the streams with base flow ANC less than 50 [mu]eq L[sup [minus]1] become acidic during storm or snowmelt episodes. Sulfate from atmospheric deposition is the dominant source of strong acid anions in acid mid-Appalachian streams. Their low pH (median, 4.9) and high levels of inorganic monomeric aluminum (median, 129 [mu]g L[sup [minus]1]) leached through soils by acidic deposition are causing damage to aquatic biota. Quantification of the extent of biological effects, however, is not possible with available data. Localized studies have shown that stream water ANC is closely related to bedrock mineralogy. Attempts to quantify this relationship across the mid-Appalachians, however, were frustrated by the lack of adequate scale geologic mapping throughout the region. Sulfate mass balance analyses indicate that soils and surface waters of the region have not yet realized the full effects of elevated sulfur deposition due to watershed sulfate retention. Sulfur retention is likely to decrease in the future, resulting in further losses of stream ANC. 70 refs., 5 figs., 4 tabs.

  2. A 120-year record of the spatial and temporal distribution of gravestone decay and acid deposition

    NASA Astrophysics Data System (ADS)

    Mooers, Howard D.; Cota-Guertin, Avery R.; Regal, Ronald R.; Sames, Anthony R.; Dekan, Amanda J.; Henkels, Linnea M.

    2016-02-01

    This investigation examines the spatial and temporal variability of marble gravestone decay throughout West Midlands County and adjacent portions of Warwickshire, Staffordshire, and Worcestershire. Gravestone decay has been used effectively as a quantitative measure of acid deposition. Numerous techniques have been used to assess gravestone decay and each is subject to different sources of error. To minimize error we focus only on marble gravestones that use the flush lead lettering technique. Decay of the marble leaves the lead lettering raised above the surface, and the distance can be measured with the use of a digital micrometer. Gravestone decay can be used to quantify the spatial and temporal distribution of acid deposition. Our gravestone decay database consists of 1417 individual measurements on 591 tombstones in 33 cemeteries and covers the period from 1860 to 2010. Sites range from industrial and residential areas to rural settings. These data allow us to establish the natural background rates of decay, the effects of urban/residential expansion, and the efficacy of environmental regulations. Decay rates vary from a minimum of 0.2 mm/century in remote rural areas to nearly 3.0 mm/century in the Birmingham City Center. The data are corrected for environmental variables, converted to acid deposition rates, and plotted at 10-year intervals from 1890 to 2010.

  3. Climate dependency of tree growth suppressed by acid deposition effects on soils in Northwest Russia

    USGS Publications Warehouse

    Lawrence, G.B.; Lapenis, A.G.; Berggren, D.; Aparin, B.F.; Smith, K.T.; Shortle, W.C.; Bailey, S.W.; Varlyguin, D.L.; Babikov, B.

    2005-01-01

    Increased tree growth in temperate and boreal forests has been proposed as a direct consequence of a warming climate. Acid deposition effects on nutrient availability may influence the climate dependency of tree growth, however. This study presents an analysis of archived soil samples that has enabled changes in soil chemistry to be tracked with patterns of tree growth through the 20th century. Soil samples collected in 1926, 1964, and 2001, near St. Petersburg, Russia, showed that acid deposition was likely to have decreased root-available concentrations of Ca (an essential element) and increased root-available concentrations of Al (an inhibitor of Ca uptake). These soil changes coincided with decreased diameter growth and a suppression of climate-tree growth relationships in Norway spruce. Expected increases in tree growth from climate warming may be limited by decreased soil fertility in regions of northern and eastern Europe, and eastern North America, where Ca availability has been reduced by acidic deposition. ?? 2005 American Chemical Society.

  4. CHEMICAL AND BIOLOGICAL STATUS OF LAKES AND STREAMS IN THE UPPER MIDWEST: ASSESSMENT OF ACIDIC DEPOSITION EFFECTS

    EPA Science Inventory

    Many lakes in three areas in the Upper Midwest--northeastern Minnesota, northern Wisconsin, and the Upper Peninsula of Michigan--have low acid neutralizing capacity (ANC) and may be susceptible to change by acidic deposition. These acidic lakes are precipitation-dominated, clearw...

  5. Evaluating the effects of galbanic acid on hydrogen peroxide-induced oxidative DNA damage in human lymphocytes

    PubMed Central

    Shirani, Kobra; Behravan, Javad; Mosaffa, Fatemeh; Iranshahi, Mehrdad; Mehmankhah, Babak; Razavi-Azarkhiavi, Kamal; Karimi, Gholamreza

    2014-01-01

    Objective: Ferula szowitsiana has been widely used for medicinal purposes around the world. The anti-oxidant effect of F. szowitsiana had been proved. The current study aims to determine the protective effects of galbanic acid, a sesquiterpene coumarin from F. szowitsiana, against hydrogen peroxide (H2O2) - induced oxidative DNA damage in human lymphocytes. Materials and Methods: Human lymphocytes were incubated with H2O2 (0, 25, 50, 100, and 200 µM), galbanic acid (200 and 400 µM) and a combination of galbanic acid (200 and 400 µM) and H2O2 (25 µM) at 4 C for 30 minutes. Solvents of galbanic acid without H2O2 were used as negative controls. Results: The findings of this study demonstrated that H2O2 exposure leads to a significant concentration-dependent increase in DNA damage. Galbanic acid did not cause DNA damage compared with the control cells. Data showed that galbanic acid does not have a protective effect against H2O2-induced oxidative DNA damage in human lymphocytes. Conclusion: According to the results, it is concluded that the capability of F. szowitsiana in reducing reactive oxygen species and the anti-inflammatory property of its methanolic extract may be due to its other ingredients. PMID:25386396

  6. Alpha-Lipoic Acid Attenuates Oxidative Damage in Organs After Sepsis.

    PubMed

    Petronilho, Fabricia; Florentino, Drielly; Danielski, Lucinéia Gainski; Vieira, Luiz Carlos; Martins, Maryane Modolon; Vieira, Andriele; Bonfante, Sandra; Goldim, Mariana Pereira; Vuolo, Francieli

    2016-02-01

    Sepsis progression is linked with the imbalance between reactive oxygen species and antioxidant enzymes. Thus, the aim of this study was to evaluate the effect of alpha-lipoic acid (ALA), a powerful antioxidant, in organs of rats submitted to sepsis. Male Wistar rats were subjected to sepsis by cecal ligation puncture (CLP) and treated with ALA or vehicle. After CLP (12 and 24 h), the myeloperoxidase (MPO) activity, protein and lipid oxidative damage, and antioxidant enzymes in the liver, kidney, heart, and lung were evaluated. ALA was effective in reducing MPO activity, lipid peroxidation in the liver, and protein carbonylation only in the kidney in 12 h after CLP. In 12 h, SOD activity increased in the kidney and CAT activity in the liver and kidney with ALA treatment. Thus, ALA was able to reduce the inflammation and oxidative stress in the liver and kidney after sepsis in rats. PMID:26431839

  7. Dry heat popping of amaranth seed might damage some of its essential amino acids.

    PubMed

    Tovar, L R; Brito, E; Takahashi, T; Miyazawa, T; Soriano, J; Fujimoto, K

    1989-12-01

    Amaranth was a major crop among the Aztecs. In Mexico the seed is popped and eaten with brown sugar. The crude protein content of the seed is 14 +/- 2% but its contents of lysine and tryptophan are 6.2 and 1.6 g/16 g N respectively. We developed a popping method based on a fluid bed system (FBS) whereas the traditional method (TM) is just to pop the seeds manually in a hot plate. Assays carried out were evaluation of racemization of the amaranth protein due to heat treatment, amino acid composition of the raw and heat treated seeds and a biological experiment testing whether leucine was the most limiting amino acid of amaranth protein. Male rats were fed both popped amaranths and roasted amaranth. Parboiled amaranth and casein were controls. The results were: (a) Lys, Arg and Cys were damaged in the heat treated seeds; (b) Asp, Met, Glu, Ala and Phe were racemized in that decreasing order in the seeds popped and roasted by the TM; (c) the estimated net protein retention (NPR) and estimated net protein utilization (NPU) of popped amaranths by either method were not different, but were lower than for the parboiled amaranth. The parboiled amaranth was not different from casein; (d) Leu was not the most limiting amino acid in any of the amaranth seeds tested. After Lys, sulfur amino acids appear to be the next most limiting in severely heat treated amaranth. The FBS seems to be a promising method for popping amaranth at industrial level. PMID:2631086

  8. Accumulation of Flavonols over Hydroxycinnamic Acids Favors Oxidative Damage Protection under Abiotic Stress.

    PubMed

    Martinez, Vicente; Mestre, Teresa C; Rubio, Francisco; Girones-Vilaplana, Amadeo; Moreno, Diego A; Mittler, Ron; Rivero, Rosa M

    2016-01-01

    Efficient detoxification of reactive oxygen species (ROS) is thought to play a key role in enhancing the tolerance of plants to abiotic stresses. Although multiple pathways, enzymes, and antioxidants are present in plants, their exact roles during different stress responses remain unclear. Here, we report on the characterization of the different antioxidant mechanisms of tomato plants subjected to heat stress, salinity stress, or a combination of both stresses. All the treatments applied induced an increase of oxidative stress, with the salinity treatment being the most aggressive, resulting in plants with the lowest biomass, and the highest levels of H2O2 accumulation, lipid peroxidation, and protein oxidation. However, the results obtained from the transcript expression study and enzymatic activities related to the ascorbate-glutathione pathway did not fully explain the differences in the oxidative damage observed between salinity and the combination of salinity and heat. An exhaustive metabolomics study revealed the differential accumulation of phenolic compounds depending on the type of abiotic stress applied. An analysis at gene and enzyme levels of the phenylpropanoid metabolism concluded that under conditions where flavonols accumulated to a greater degree as compared to hydroxycinnamic acids, the oxidative damage was lower, highlighting the importance of flavonols as powerful antioxidants, and their role in abiotic stress tolerance. PMID:27379130

  9. Accumulation of Flavonols over Hydroxycinnamic Acids Favors Oxidative Damage Protection under Abiotic Stress

    PubMed Central

    Martinez, Vicente; Mestre, Teresa C.; Rubio, Francisco; Girones-Vilaplana, Amadeo; Moreno, Diego A.; Mittler, Ron; Rivero, Rosa M.

    2016-01-01

    Efficient detoxification of reactive oxygen species (ROS) is thought to play a key role in enhancing the tolerance of plants to abiotic stresses. Although multiple pathways, enzymes, and antioxidants are present in plants, their exact roles during different stress responses remain unclear. Here, we report on the characterization of the different antioxidant mechanisms of tomato plants subjected to heat stress, salinity stress, or a combination of both stresses. All the treatments applied induced an increase of oxidative stress, with the salinity treatment being the most aggressive, resulting in plants with the lowest biomass, and the highest levels of H2O2 accumulation, lipid peroxidation, and protein oxidation. However, the results obtained from the transcript expression study and enzymatic activities related to the ascorbate-glutathione pathway did not fully explain the differences in the oxidative damage observed between salinity and the combination of salinity and heat. An exhaustive metabolomics study revealed the differential accumulation of phenolic compounds depending on the type of abiotic stress applied. An analysis at gene and enzyme levels of the phenylpropanoid metabolism concluded that under conditions where flavonols accumulated to a greater degree as compared to hydroxycinnamic acids, the oxidative damage was lower, highlighting the importance of flavonols as powerful antioxidants, and their role in abiotic stress tolerance. PMID:27379130

  10. Assessment of lake sensitivity to acidic deposition in national parks of the Rocky Mountains

    USGS Publications Warehouse

    Nanus, L.; Williams, M.W.; Campbell, D.H.; Tonnessen, K.A.; Blett, T.; Clow, D.W.

    2009-01-01

    The sensitivity of high-elevation lakes to acidic deposition was evaluated in five national parks of the Rocky Mountains based on statistical relations between lake acid-neutralizing capacity concentrations and basin characteristics. Acid-neutralizing capacity (ANC) of 151 lakes sampled during synoptic surveys and basin-characteristic information derived from geographic information system (GIS) data sets were used to calibrate the statistical models. The explanatory basin variables that were considered included topographic parameters, bedrock type, and vegetation type. A logistic regression model was developed, and modeling results were cross-validated through lake sampling during fall 2004 at 58 lakes. The model was applied to lake basins greater than 1 ha in area in Glacier National Park (n = 244 lakes), Grand Teton National Park (n = 106 lakes), Great Sand Dunes National Park and Preserve (n = 11 lakes), Rocky Mountain National Park (n = 114 lakes), and Yellowstone National Park (n = 294 lakes). Lakes that had a high probability of having an ANC concentration 3000 m, with 80% of the catchment bedrock having low buffering capacity. The modeling results indicate that the most sensitive lakes are located in Rocky Mountain National Park and Grand Teton National Park. This technique for evaluating the lake sensitivity to acidic deposition is useful for designing long-term monitoring plans and is potentially transferable to other remote mountain areas of the United States and the world.

  11. Comparative study of the laser damage threshold and optical characteristics of Ta2O5-SiO2 multilayers deposited using various methods

    NASA Astrophysics Data System (ADS)

    Botha, Roelene; Schwyn Thöny, Silvia; Grössl, Martin; Mourad, Safer; Maissen, Clau; Venter, Jacobus I.; Südmeyer, Thomas; Hoffmann, Martin; Bulkin, Pavel V.; Linz-Dittrich, Sabine; Bischof, David; Michler, Markus; Rinner, Stefan J.; Ettemeyer, Andreas

    2015-11-01

    Manufacturing processes from the private and academic sectors were used to deposit anti-reflective and high-reflective coatings composed of Ta2O5 - SiO2 multilayers. Used deposition techniques included three Ion Assisted Deposition (IAD) systems and an Ion Beam Sputtering (IBS) system. Coatings were performed on fused silica (Corning 7980) substrates polished by two different suppliers. LIDT Measurements were performed using a Q-Switched Nd:YAG laser operating at 1064nm. The paper presents a comparison of the coatings in terms of laser damage threshold values, optical properties and surface quality.

  12. The Effects of Gaseous Ozone and Nitric Acid Deposition on two Crustose Lichen Species From Joshua Tree National Park

    NASA Astrophysics Data System (ADS)

    Hessom, Elizabeth Curie

    Lichens are dependent on atmospheric deposition for much of their water and nutrients, and due to their sensitivity to pollutants, are commonly used as bioindicators for air quality. While studies have focused on epiphytic (tree dwelling) lichens as bioindicators, virtually nothing is known about crustose (rock dwelling) lichens. The atmospheric pollutants ozone (O 3) and nitric acid (HNO3) are two major pollutants found within the Los Angeles Basin. While recent O3 research suggests it does not significantly affect lichen growth, HNO3 appears to be phytotoxic to some lichens. As both of these pollutants are deposited downwind from the L.A. basin into Joshua Tree National Park (JOTR), lichen species located in the park may provide a sensitive indicator of pollution effects. This research studied two lichen species of particular interest from Joshua Tree National Park, Lobothallia praeradiosa (Nyl.) Hafellner, and Acarospora socialis H. Magn., both of which are crustose species with unknown sensitivities to O3, as well as hypothesized and unknown sensitivities to nitrogen compounds, respectively. Little research exists for either species, possibly because of the difficulty in working with crustose lichens. This research attempted to expand the background knowledge of these species by exposing them to varying levels of O3 and HNO3, to ascertain their physiological responses. Physiological measures of chlorophyll fluorescence, dark respiration, microscopic imaging, and lichen washes (as a proxy for membrane leakage), were measured throughout the exposure period. Results indicated that both species had similar sensitivities to O3 and HNO3. Both species registered physical damage during the O3 fumigation, as well as a decrease in respiration. Neither species showed major physical damage to HNO3, but both manifested a decrease in chlorophyll fluorescence, suggesting damage to the photosynthetic systems of the algae symbiont. These results suggest that both of these

  13. An Investigation into the Association between DNA Damage and Dietary Fatty Acid in Men with Prostate Cancer

    PubMed Central

    Bishop, Karen S.; Erdrich, Sharon; Karunasinghe, Nishi; Han, Dug Yeo; Zhu, Shuotun; Jesuthasan, Amalini; Ferguson, Lynnette R.

    2015-01-01

    Prostate cancer is a growing problem in New Zealand and worldwide, as populations adopt a Western style dietary pattern. In particular, dietary fat is believed to be associated with oxidative stress, which in turn may be associated with cancer risk and development. In addition, DNA damage is associated with the risk of various cancers, and is regarded as an ideal biomarker for the assessment of the influence of foods on cancer. In the study presented here, 20 men with prostate cancer adhered to a modified Mediterranean style diet for three months. Dietary records, blood fatty acid levels, prostate specific antigen, C-reactive protein and DNA damage were assessed pre- and post-intervention. DNA damage was inversely correlated with dietary adherence (p = 0.013) and whole blood monounsaturated fatty acids (p = 0.009) and oleic acid (p = 0.020). DNA damage was positively correlated with the intake of dairy products (p = 0.043), red meat (p = 0.007) and whole blood omega-6 polyunsaturated fatty acids (p = 0.015). Both the source and type of dietary fat changed significantly over the course of the dietary intervention. Levels of DNA damage were correlated with various dietary fat sources and types of dietary fat. PMID:25580814

  14. Chemical and biological recovery from acid deposition within the Honnedaga Lake watershed, New York, USA.

    PubMed

    Josephson, Daniel C; Robinson, Jason M; Chiotti, Justin; Jirka, Kurt J; Kraft, Clifford E

    2014-07-01

    Honnedaga Lake in the Adirondack region of New York has sustained a heritage brook trout population despite decades of atmospheric acid deposition. Detrimental impacts from acid deposition were observed from 1920 to 1960 with the sequential loss of acid-sensitive fishes, leaving only brook trout extant in the lake. Open-lake trap net catches of brook trout declined for two decades into the late 1970s, when brook trout were considered extirpated from the lake but persisted in tributary refuges. Amendments to the Clean Air Act in 1990 mandated reductions in sulfate and nitrogen oxide emissions. By 2000, brook trout had re-colonized the lake coincident with reductions in surface-water sulfate, nitrate, and inorganic monomeric aluminum. No changes have been observed in surface-water acid-neutralizing capacity (ANC) or calcium concentration. Observed increases in chlorophyll a and decreases in water clarity reflect an increase in phytoplankton abundance. The zooplankton community exhibits low species richness, with a scarcity of acid-sensitive Daphnia and dominance by acid-tolerant copepods. Trap net surveys indicate that relative abundance of adult brook trout population has significantly increased since the 1970s. Brook trout are absent in 65 % of tributaries that are chronically acidified with ANC of <0 μeq/L and toxic aluminum levels (>2 μmol/L). Given the current conditions, a slow recovery of chemistry and biota is expected in Honnedaga Lake and its tributaries. We are exploring the potential to accelerate the recovery of brook trout abundance in Honnedaga Lake through lime applications to chronically and episodically acidified tributaries. PMID:24671614

  15. Interactions of aluminum with forest soils and vegetation: Implications for acid deposition

    SciTech Connect

    Maynard, A.A.

    1989-01-01

    Recent evidence suggests that an important ecological consequence of acidic deposition is increased aluminum mobilization. There is concern that increased aluminum activity may produce toxic effects in forested ecosystems. My studies were concerned with the behavior of pedogenic and added aluminum in soils derived from chemically different parent material. Soil aluminum was related to the aluminum content of the vegetation found growing in the soils. In addition, aluminum levels of forest litter was compared to levels determined 40 years ago. Field, greenhouse, and laboratory investigations were conducted in which the effects of aluminum concentration on germination and early growth was determined. Soils were then used in greenhouse and laboratory studies to establish patterns of soil and plant aluminum behavior with implications to acid deposition. Results show that the amount of aluminum extracted was related to the pH value of the extracting solution and to the chemical characteristics of the soil. Some acid rain solutions extracted measurable amounts of aluminum from selected primary minerals. Germination and early growth of Pinus radiata was controlled by levels of aluminum in the soil or in solution. Field studies indicated that most forest species were sensitive to rising levels of aluminum in the soil. In general, ferns and fern allies were less sensitive to very high levels of aluminum in the soil, continuing to grow when more advanced dicots have disappeared. Aluminum tissue levels of all species were related to the concentration of aluminum in the soil as was the reappearance of species. Aluminum levels in leaf litter have risen at least 50% in the last 40 years. These values were consistent over 3 years. The implications to acid deposition were discussed.

  16. Dihydrolipoic acid inhibits tetrachlorohydroquinone-induced tumor promotion through prevention of oxidative damage.

    PubMed

    Wang, Ying-Jan; Yang, Ming-Chen; Pan, Ming-Hsiung

    2008-12-01

    alpha-Lipoic acid (LA) has been intensely investigated as a therapeutic agent for several diseases, including hepatic disorder and diabetic polyneuropathy. However, the effects of LA or its reduced form, dihydrolipoic acid (DHLA), on cancer chemoprevention has seldom been studied. Tetrachlorohydroquinone (TCHQ) is a toxic metabolite of pentachlorophenol (PCP) that was proven to be a tumor promoter in our previous study. We recently reported that DHLA can inhibit DMBA/TPA-induced skin tumor formation through its anti-inflammatory and anti-oxidizing functions. In the present study, we further examined the effects of DHLA on DMBA/TCHQ-induced skin tumor formation and the possible mechanisms. We found that DHLA significantly inhibited tumor incidence and tumor multiplicity in DMBA/TCHQ-induced skin tumor formation. Administration of DHLA prevented ROS generation, cytotoxicity, genotoxicity and apoptotic cell death in cells treated with TCHQ. In addition, activation of JNK and p38 MAPK may be involved in TCHQ-mediated apoptosis. Nonetheless, the detailed mechanisms of DHLA in attenuating TCHQ-induced skin tumor promotion are still unclear and need to be further investigated. We conclude that DHLA may be a useful protective agent against TCHQ-induced toxicity in epithelial cells, and for reversing TCHQ-induced damage in mouse skin. PMID:18951944

  17. Azithromycin and erythromycin ameliorate the extent of colonic damage induced by acetic acid in rats

    SciTech Connect

    Mahgoub, Afaf . E-mail: afaf_mahgoub@yahoo.com; El-Medany, Azza; Mustafa, Ali; Arafah, Maha; Moursi, Mahmoud

    2005-05-15

    Ulcerative colitis is a common inflammatory bowel disease (IBD) of unknown etiology. Recent studies have revealed the role of some microorganisms in the initiation and perpetuation of IBD. The role of antibiotics in the possible modulation of colon inflammation is still uncertain. In this study, we evaluated the effects of two macrolides, namely azithromycin and erythromycin, at different doses on the extent and severity of ulcerative colitis caused by intracolonic administration of 3% acetic acid in rats. The lesions and the inflammatory response were assessed by histology and measurement of myeloperoxidase (MPO) activity, nitric oxide synthetase (NOS) and tumor necrosis factor alpha (TNF{alpha}) in colonic tissues. Inflammation following acetic acid instillation was characterized by oedema, diffuse inflammatory cell infiltration and necrosis. Increase in MPO, NOS and TNF{alpha} was detected in the colonic tissues. Administration of either azithromycin or erythromycin at different dosage (10, 20 and 40 mg/kg orally, daily for 5 consecutive days) significantly (P < 0.05) reduced the colonic damage, MPO and NOS activities as well as TNF{alpha} level. This reduction was highly significant with azithromycin when given at a dose of 40 mg/kg. It is concluded that azithromycin and erythromycin may have a beneficial therapeutic role in ulcerative colitis.

  18. Investigation of damage threshold of ion beam deposited oxide thin film optics for high-peak-power short-pulse lasers

    NASA Astrophysics Data System (ADS)

    Fitzgerald Dummer, Ann M.; Brizuela, Fernando; Duskis, Charissa; Luther, Brad; Larotonda, Miguel; Rocca, Jorge J.; George, Jason; Kohli, Sandeep; McCurdy, Pat; Menoni, Carmen S.

    2004-09-01

    In this work we report on the damage threshold of ion beam deposited oxide films designed for high peak power short pulse laser systems. Single layers of ZrO2, SiO2, Al2O3, TiO2, and Ta2O5 and multilayers of Al2O 3/TiO2, SiO2/Ta2O5, and SiO2/ZrO2 were grown on polished borosilicate glass substrates using ion beam sputter deposition. Deposition conditions were optimized to yield fully oxidized films as determined from x-ray photoelectron spectroscopy (XPS). Damage threshold testing was performed using an amplified Ti:Sapphire laser producing a train of 120 picosecond pulses at a wavelength of 800 nm. The laser output was focused with a lens to generate fluences ranging from 0.1 to 24 J/cm2. The highest damage threshold of 15.4 J/cm2 was measured for a single layer film of SiO2. The damage threshold of high reflectance and anti-reflection multilayer coatings fabricated for 800 nm applications was evaluated using the same procedure as for the single layer films. Highest damage thresholds of 2.5 and 3.5 J/cm2 were measured for a 6-pair ZrO2/SiO2 high reflectance coating and a 5 layer anti-reflection coating of the same materials.

  19. An Investigation of Solid-State Amidization and Imidization Reactions in Vapor Deposited Poly (amic acid)

    SciTech Connect

    Anthamatten, M; Letts, S A; Day, K; Cook, R C; Gies, A P; Hamilton, T P; Nonidez, W K

    2004-06-28

    The condensation polymerization reaction of 4,4'-oxydianiline (ODA) with pyromellitic dianhydride (PMDA) to form poly(amic acid) and the subsequent imidization reaction to form polyimide were investigated for films prepared using vapor deposition polymerization techniques. Fourier-transform infrared spectroscopy (FT-IR), thermal analysis, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of films at different temperatures indicate that additional solid-state polymerization occurs prior to imidization reactions. Experiments reveal that, upon vapor deposition, poly(amic acid) oligomers form that have a number-average molecular weight of about 1500 Daltons. Between 100 - 130 C these chains undergo additional condensation reaction to form slightly higher molecular weight oligomers. Calorimetry measurements show that this reaction is exothermic ({Delta}H {approx} -30 J/g) with an activation energy of about 120 kJ/mol. Experimental reaction enthalpies are compared to results from ab initio molecular modeling calculations to estimate the number of amide groups formed. At higher temperatures (150 - 300 C) imidization of amide linkages occurs as an endothermic reaction ({Delta}H {approx} +120 J/g) with an activation energy of about 130 kJ/mol. Solid-state kinetics were found to depend on reaction conversion as well as the processing conditions used to deposit films.

  20. ACIDIC DEPOSITION AND THE CORROSION AND DETERIORATION OF MATERIALS IN THE ATMOSPHERE: A BIBLIOGRAPHY, 1880-1982

    EPA Science Inventory

    The bibliography contains more than 1300 article citations and abstracts on the effects of acidic deposition, air pollutants, and biological and meteorological factors on the corrosion and deterioration of materials in the atmosphere. The listing includes citations for the years ...

  1. Declining acidic deposition begins reversal of forest-soil acidification in the northeastern U.S. and eastern Canada

    USGS Publications Warehouse

    Lawrence, Gregory B.; Hazlett, Paul W.; Fernandez, Ivan J.; Ouimet, Rock; Bailey, Scott W.; Shortle, Walter C.; Smith, Kevin T.; Antidormi, Michael

    2015-01-01

    Decreasing trends in acidic deposition levels over the past several decades have led to partial chemical recovery of surface waters. However, depletion of soil Ca from acidic deposition has slowed surface water recovery and led to the impairment of both aquatic and terrestrial ecosystems. Nevertheless, documentation of acidic deposition effects on soils has been limited, and little is known regarding soil responses to ongoing acidic deposition decreases. In this study, resampling of soils in eastern Canada and the northeastern U.S. was done at 27 sites exposed to reductions in wet SO42– deposition of 5.7–76%, over intervals of 8–24 y. Decreases of exchangeable Al in the O horizon and increases in pH in the O and B horizons were seen at most sites. Among all sites, reductions in SO42– deposition were positively correlated with ratios (final sampling/initial sampling) of base saturation (P < 0.01) and negatively correlated with exchangeable Al ratios (P < 0.05) in the O horizon. However, base saturation in the B horizon decreased at one-third of the sites, with no increases. These results are unique in showing that the effects of acidic deposition on North American soils have begun to reverse.

  2. Declining Acidic Deposition Begins Reversal of Forest-Soil Acidification in the Northeastern U.S. and Eastern Canada.

    PubMed

    Lawrence, Gregory B; Hazlett, Paul W; Fernandez, Ivan J; Ouimet, Rock; Bailey, Scott W; Shortle, Walter C; Smith, Kevin T; Antidormi, Michael R

    2015-11-17

    Decreasing trends in acidic deposition levels over the past several decades have led to partial chemical recovery of surface waters. However, depletion of soil Ca from acidic deposition has slowed surface water recovery and led to the impairment of both aquatic and terrestrial ecosystems. Nevertheless, documentation of acidic deposition effects on soils has been limited, and little is known regarding soil responses to ongoing acidic deposition decreases. In this study, resampling of soils in eastern Canada and the northeastern U.S. was done at 27 sites exposed to reductions in wet SO4(2-) deposition of 5.7-76%, over intervals of 8-24 y. Decreases of exchangeable Al in the O horizon and increases in pH in the O and B horizons were seen at most sites. Among all sites, reductions in SO4(2-) deposition were positively correlated with ratios (final sampling/initial sampling) of base saturation (P < 0.01) and negatively correlated with exchangeable Al ratios (P < 0.05) in the O horizon. However, base saturation in the B horizon decreased at one-third of the sites, with no increases. These results are unique in showing that the effects of acidic deposition on North American soils have begun to reverse. PMID:26495963

  3. Sensitivity of stream basins in Shenandoah National Park to acid deposition

    USGS Publications Warehouse

    Lynch, D.D.; Dise, N.B.

    1985-01-01

    Six synoptic surveys of 56 streams that drain the Shenandoah National Park, Virginia, were conducted in cooperation with the University of Virginia to evaluate sensitivity of dilute headwater streams to acid deposition and to determine the degree of acidification of drainage basins. Flow-weighted alkalinity concentration of most streams is below 200 microequivalents per liter, which is considered the threshold of sensitivity. Streams draining resistant siliceous bedrocks have an extreme sensitivity (alkalinity below 20 microequivalents/L); those draining granite and granodiorite have a high degree of sensitivity (20 to 100 microequivalents/L); and streams draining metamorphosed volcanics have moderate to marginal sensitivity (100 to 200 microequivalents/L). A comparison of current stream water chemistry to that predicted by a model based on carbonic acid weathering reactions suggests that all basins in the Park shows signs of acidification by atmospheric deposition. Acidification is defined as a neutralization of stream water alkalinity and/or an increase in the base cation weathering rate. Acidification averages 50 microequivalents/L, which is fairly evenly distributed in the Park. However, the effects of acidification are most strongly felt in extremely sensitive basins, such as those underlain by the Antietam Formation, which have stream water pH values averaging 4.99 and a mineral acidity of 7 microequivalents/L. (USGS)

  4. Implications of a gradient in acid and ion deposition across the northern Great Lakes states

    SciTech Connect

    Glass, G.E.; Loucks, O.L.

    1986-01-01

    Average precipitation pH, 1979-1982, declines from west to east from 5.3 to 4.3 along a cross section of sites in Minnesota, Wisconsin, and Michigan. This answers questions about the seasonal and geographic pattern of anthropogenic acid precursor emissions and reaction products (SO/sub 4//sup 2 -/, NO/sub 3//sup -/, H/sup +/, NH/sub 2//sup +/) that increase from west to east. Except for higher concentrations of Ca/sup 2 +/ and Mg/sup 2 +/ observed at one site in the cultivated areas of southwestern Minnesota, the contribution of soil-related metal cations to the total ions in solution is small (17%) and relatively uniform across the region. Significant seasonal and geographic patterns in precipitation chemistry and deposition values are observed. Close correspondence of the sums of strong acid anions with the sums of hydrogen and ammonium ions in precipitation is observed, indicating anthropogenic sources of sulfur and nitrogen oxides. Present atmospheric inputs show close chemical correspondence when precipitation chemistry values are compared to the resulting ionic composition of weakly buffered lakes in north central Wisconsin and northern Michigan. The wet deposition of total acidity in the middle and eastern part of the region is comparable to that of impacted sites in the Adirondacks and in regions of Scandinavia. 39 references, 3 figures, 6 tables.

  5. Pulsed and continuous wave acrylic acid radio frequency plasma deposits: plasma and surface chemistry.

    PubMed

    Voronin, Sergey A; Zelzer, Mischa; Fotea, Catalin; Alexander, Morgan R; Bradley, James W

    2007-04-01

    Plasma polymers have been formed from acrylic acid using a pulsed power source. An on-pulse duration of 100 micros was used with a range of discharge off-times between 0 (continuous wave) and 20,000 micros. X-ray photoelectron spectroscopy (XPS) has been used in combination with trifluoroethanol (TFE) derivatization to quantify the surface concentration of the carboxylic acid functionality in the deposit. Retention of this functionality from the monomer varied from 2% to 65%. When input power was expressed as the time-averaged energy per monomer molecule, E(mean), the deposit chemistry achieved could be described using a single relationship for all deposition conditions. Deposition rates were monitored using a quartz crystal microbalance, which revealed a range from 20 to 200 microg m(-2) s(-1), and these fell as COOH functional retention increased. The flow rate was found to be the major determinant of the deposition rate, rather than being uniquely defined by E(mean), connected to the rate at which fresh monomer enters the system in the monomer deficient regime. The neutral species were collected in a time-averaged manner. As the energy delivered per molecule in the system (E(mean)) decreased, the amount of intact monomer increased, with the average neutral mass approaching 72 amu as E(mean) tends to zero. No neutral oligomeric species were detected. Langmuir probes have been used to determine the temporal evolution of the density and temperature of the electrons in the plasma and the plasma potential adjacent to the depositing film. It has been found that even 500 micros into the afterglow period that ionic densities are still significant, 5-10% of the on-time density, and that ion accelerating sheath potentials fall from 40 V in the on-time to a few volts in the off-time. We have made the first detailed, time- and energy-resolved mass spectrometry measurements in depositing acrylic acid plasma. These have allowed us to identify and quantify the positive ion

  6. Growth hormone reverses excitotoxic damage induced by kainic acid in the green iguana neuroretina.

    PubMed

    Ávila-Mendoza, José; Mora, Janeth; Carranza, Martha; Luna, Maricela; Arámburo, Carlos

    2016-08-01

    It is known that growth hormone (GH) is expressed in extrapituitary tissues, including the nervous system and ocular tissues, where it is involved in autocrine/paracrine actions related to cell survival and anti-apoptosis in several vertebrates. Little is known, however, in reptiles, so we analyzed the expression and distribution of GH in the eye of green iguana and its potential neuroprotective role in retinas that were damaged by the intraocular administration of kainic acid (KA). It was found, by Western blotting, that GH-immunoreactivity (GH-IR) was expressed as two isoforms (15 and 26kDa, under reducing conditions) in cornea, vitreous, retina, crystalline, iris and sclera, in varying proportions. Also, two bands for the growth hormone receptor (GHR)-IR were observed (70 and 44kDa, respectively) in the same tissues. By immunofluorescence, GH-IR was found in neurons present in several layers of the neuroretina (inner nuclear [INL], outer nuclear [ONL] and ganglion cell [GCL] layers) as determined by its co-existence with NeuN, but not in glial cells. In addition, GH and GHR co-expression was found in the same cells, suggesting paracrine/autocrine interactions. KA administration induced retinal excitotoxic damage, as determined by a significant reduction of the cell density and an increase in the appearance of apoptotic cells in the INL and GCL. In response to KA injury, both endogenous GH and Insulin-like Growth Factor I (IGF-I) expression were increased by 70±1.8% and 33.3±16%, respectively. The addition of exogenous GH significantly prevented the retinal damage produced by the loss of cytoarchitecture and cell density in the GCL (from 4.9±0.79 in the control, to 1.45±0.2 with KA, to 6.35±0.49cell/mm(2) with KA+GH) and in the INL (19.12±1.6, 10.05±1.9, 21.0±0.8cell/mm(2), respectively) generated by the long-term effect of 1mM KA intraocular administration. The co-incubation with a specific anti-GH antibody, however, blocked the protective effect of GH

  7. Application of a Depositional Facies Model to an Acid Mine Drainage Site▿ †

    PubMed Central

    Brown, Juliana F.; Jones, Daniel S.; Mills, Daniel B.; Macalady, Jennifer L.; Burgos, William D.

    2011-01-01

    Lower Red Eyes is an acid mine drainage site in Pennsylvania where low-pH Fe(II) oxidation has created a large, terraced iron mound downstream of an anoxic, acidic, metal-rich spring. Aqueous chemistry, mineral precipitates, microbial communities, and laboratory-based Fe(II) oxidation rates for this site were analyzed in the context of a depositional facies model. Depositional facies were defined as pools, terraces, or microterracettes based on cm-scale sediment morphology, irrespective of the distance downstream from the spring. The sediments were composed entirely of Fe precipitates and cemented organic matter. The Fe precipitates were identified as schwertmannite at all locations, regardless of facies. Microbial composition was studied with fluorescence in situ hybridization (FISH) and transitioned from a microaerophilic, Euglena-dominated community at the spring, to a Betaproteobacteria (primarily Ferrovum spp.)-dominated community at the upstream end of the iron mound, to a Gammaproteobacteria (primarily Acidithiobacillus)-dominated community at the downstream end of the iron mound. Microbial community structure was more strongly correlated with pH and geochemical conditions than depositional facies. Intact pieces of terrace and pool sediments from upstream and downstream locations were used in flowthrough laboratory reactors to measure the rate and extent of low-pH Fe(II) oxidation. No change in Fe(II) concentration was observed with 60Co-irradiated sediments or with no-sediment controls, indicating that abiotic Fe(II) oxidation was negligible. Upstream sediments attained lower effluent Fe(II) concentrations compared to downstream sediments, regardless of depositional facies. PMID:21097582

  8. Effects of ascorbic acid on UV light-mediated photoreceptor damage in isolated rat retina

    PubMed Central

    Tokuda, Kazuhiro; Zorumski, Charles F.; Izumi, Yukitoshi

    2007-01-01

    Concerns have been raised about whether operating microscopes and endoillumination used during ophthalmic surgeries contribute to retinal damage. Despite the recognition that ascorbic acid (vitamin C) helps to protect the eye from light and the abundance of vitamin C in the retina, artificial aqueous humors used during surgery only contain the antioxidant glutathione. To test whether inclusion of antioxidants other than glutathione in surgical solutions might help to preserve retinal integrity, we studied the effects of vitamin C on acute toxicity in isolated rat retinas. Male Sprague-Dawley rats (PND 30 ± 2) were sacrificed for retinal isolation. In the presence or absence of vitamin C (1 or 3 mM), retinas were exposed to 302 nm ultraviolet B (UVB) light for 1 hour and were incubated for a total of 5 hours at 30°C. Retinal damage was assessed by morphological examination and biochemical assay measuring the amount of lactate dehydrogenase (LDH) released from injured cells. In control retinas, LDH release was significantly increased after UVB exposure. The presence of 1 mM vitamin C in the incubation media significantly reduced LDH release during the post-incubation period following UV exposure. No difference was found between 1 mM and 3 mM vitamin C. Microscopic examination revealed that disorganization in the outer nuclear layer after UVB exposure was markedly attenuated by administration of 1 mM vitamin C. One mM vitamin C, a concentration found in the anterior chamber in humans, but not glutathione, prevented phototoxic injury following UV exposure. Although vitamin C itself cannot be used in intraocular irrigating solutions because of adverse interactions with iron released during bleeding, inclusion of antioxidants equivalent to vitamin C should be considered to help protect the retina from intraoperative light toxicity. PMID:17222826

  9. P450-dependent arachidonic acid metabolism and angiotensin II-induced renal damage.

    PubMed

    Kaergel, Eva; Muller, Dominik N; Honeck, Horst; Theuer, Juergen; Shagdarsuren, Erdenechimeg; Mullally, Alexander; Luft, Friedrich C; Schunck, Wolf-Hagen

    2002-09-01

    Transgenic rats overexpressing both human renin and angiotensinogen genes (dTGR) develop hypertension, inflammation, and renal failure. We tested the hypothesis that these pathological features are associated with changes in renal P450-dependent arachidonic acid (AA) metabolism. Samples were prepared from 5- and 7-week-old dTGR and from normotensive Sprague-Dawley (SD) rats, ie, before and after the dTGR developed severe hypertension and albuminuria. At both stages, dTGR showed significantly lower renal microsomal AA epoxygenase and hydroxylase activities that reached 63% and 76% of the control values at week 7. Furthermore, the protein levels of several potential AA epoxygenases (CYP2C11, CYP2C23, and CYP2J) were significantly reduced. Immunoinhibition studies identified CYP2C23 as the major AA epoxygenase, both in dTGR and SD rats. Immunohistochemistry showed that CYP2C23 was localized in cortical and outer medullary tubules that progressively lost this enzyme from week 5 to week 7 in dTGR. CYP2C11 expression occurred only in the outer medullary tubules and was markedly reduced in dTGR compared with age-matched SD rats. These findings indicate site-specific decreases in the availability of AA epoxygenase products in the kidney of dTGR. In contrast to renal microsomes, liver microsomes of dTGR and SD rats showed no change in the expression and activity of AA epoxygenases and hydroxylases. We conclude that hypertension and end-organ damage in dTGR is associated with kidney-specific downregulation of P450-dependent AA metabolism. Because the products of AA epoxygenation have anti-inflammatory properties, this alteration may contribute to uncontrolled renal inflammation, which is a major cause of renal damage in dTGR. PMID:12215466

  10. Beneficial effects of chlorogenic acid on alcohol-induced damage in PC12 cells.

    PubMed

    Fang, Shi-Qi; Wang, Yong-Tang; Wei, Jing-Xiang; Shu, Ya-Hai; Xiao, Lan; Lu, Xiu-Min

    2016-04-01

    As one of the most commonly abused psychotropic substances, ethanol exposure has deleterious effects on the central nervous system (CNS). The most detrimental results of ethanol exposure during development are the loss of neurons in brain regions such as the hippocampus and neocortex, which may be related to the apoptosis and necrosis mediated by oxidative stress. Recent studies indicated that a number of natural drugs from plants play an important role in protection of nerve cells from damage. Among these, it has been reported that chlorogenic acid (CA) has neuroprotective effects against oxidative stress. Thus, it may play some beneficial effects on ethanol-induced neurotoxicity. However, the effects of CA on ethanol-induced nerve damage remain unclear. In order to investigate the protective effects of CA on alcohol-induced apoptosis in rat pheochromocytoma PC12 cells, in the present study, cell viability and the optimal dosage of CA were first quantified by MTT assay. Then, the cell apoptosis and cell cycle were respectively investigated by Hoechst 33258 staining and flow cytometer (FCM). To further clarify the possible mechanism, followed with the test of mitochondria transmembrane potential with Rhodamine 123 (Rho 123) staining, the expression of Bcl-2, Capase-3 and growth associated protein-43 (GAP-43) were analyzed by immunofluorescence assay separately. The results showed that treatment with 500mM alcohol decreased the cell viability and then significantly induced apoptosis in PC12 cells. However, when pretreated with different concentrations of CA (1, 5, 10, 50μM), cell viability increased in different degree. Comparatively, CA with the concentration of 10μM most effectively promoted the proliferation of damaged cells, increased the distribution ratio of the cells at the G2/M and S phases, and enhanced mitochondria transmembrane potential. This appears to be in agreement with up-regulation of the expression of Bcl-2 and GAP-43, and down-regulation of the

  11. Acidity, nutrients, and minerals in atmospheric precipitation over Florida: deposition patterns, mechanisms and ecological effects

    SciTech Connect

    Brezonik, P.L.; Hendry, C.D. Jr.; Edgerton, E.S.; Schulze, R.L.; Crisman, T.L.

    1983-06-01

    A monitoring network of 21 bulk and 4 wet/dry collectors located throughout Florida measured spatial and temporal trends during a one-year period from May 1978 to April 1979. The project summary notes that statewide deposition rates of nitrogen and phosphorus were below the loading rates associated with eutrophication, although nutrient concentrations were higher during the summer. Overall, pH appears to have relatively small effects (in the range 4.7-6.8) on community structure in soft-water Florida lakes. More dramatic effects could occur under more acidic conditions in the future. 4 references, 5 figures, 1 table.

  12. Amino acid digestibility of heat damaged distillers dried grains with solubles fed to pigs

    PubMed Central

    2013-01-01

    The primary objective of this experiment was to determine the effects of heat treatment on the standardized ileal digestibility (SID) of amino acids (AA) in corn distillers dried grains with solubles (DDGS) fed to growing pigs. The second objective was to develop regression equations that may be used to predict the concentration of SID AA in corn DDGS. A source of corn DDGS was divided into 4 batches that were either not autoclaved or autoclaved at 130°C for 10, 20, or 30 min. Four diets containing DDGS from each of the 4 batches were formulated with DDGS being the only source of AA and CP in the diets. A N-free diet also was formulated and used to determine the basal endogenous losses of CP and AA. Ten growing pigs (initial BW: 53.5 ± 3.9 kg) were surgically equipped with a T-cannula in the distal ileum and allotted to a replicated 5 × 4 Youden square design with 5 diets and 4 periods in each square. The SID of CP decreased linearly (P < 0.05) from 77.9% in non-autoclaved DDGS to 72.1, 66.1, and 68.5% in the DDGS samples that were autoclaved for 10, 20, or 30 min, respectively. The SID of lysine was quadratically reduced (P < 0.05) from 66.8% in the non-autoclaved DDGS to 54.9, 55.3, and 51.9% in the DDGS autoclaved for 10, 20, or 30 min, respectively. The concentrations of SID Arginine, Histidine, Leucine, Lysine, Methionine, Phenylalanine, or Threonine may be best predicted by equations that include the concentration of acid detergent insoluble N in the model (r2 = 0.76, 0.68, 0.67, 0.84, 0.76, 0.73, or 0.54, respectively). The concentrations of SID Isoleucine and Valine were predicted (r2 = 0.58 and 0.54, respectively) by the Lysine:CP ratio, whereas the concentration of SID Tryptophan was predicted (r2 = 0.70) by the analyzed concentration of Tryptophan in DDGS. In conclusion, the SID of AA is decreased as a result of heat damage and the concentration of SID AA in heat-damaged DDGS may be predicted by regression equations

  13. HCl in rocket exhaust clouds - Atmospheric dispersion, acid aerosol characteristics, and acid rain deposition

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Sebacher, D. I.; Bendura, R. J.; Wornom, D. E.

    1983-01-01

    Both measurements and model calculations of the temporal dispersion of peak HCl (g + aq) concentration in Titan III exhaust clouds are found to be well characterized by one-term power-law decay expressions. The respective coefficients and decay exponents, however, are found to vary widely with meteorology. The HCl (g), HCl (g + aq), dewpoint, and temperature-pressure-altitude data for Titan III exhaust clouds are consistent with accurately calculated HCl/H2O vapor-liquid compositions for a model quasi-equilibrated flat surface aqueous aerosol. Some cloud evolution characteristics are also defined. Rapid and extensive condensation of aqueous acid clearly occurs during the first three min of cloud rise. Condensation is found to be intensified by the initial entrainment of relatively moist ambient air from lower levels, that is, from levels below eventual cloud stabilization. It is pointed out that if subsequent dilution air at stabilization altitude is significantly drier, a state of maximum condensation soon occurs, followed by an aerosol evaporation phase.

  14. Influence of laser conditioning on laser induced damage threshold of single layers of ZrO2 with various deposition conditions

    NASA Astrophysics Data System (ADS)

    Sahraee, M.; Reza Fallah, H.; Zabolian, H.; Moradi, B.; Haji Mahmoodzade, M.

    2015-04-01

    Single layers of ZrO2 were coated at base pressure of 10-5 mbar by electron beam evaporation (EBE) technique. The influence of oxygen partial pressure on spectral properties and laser induced damage threshold (LIDT) of the samples were investigated. Spectral transmittance of the samples was measured by spectrophotometer. Laser induced damage threshold was detected according to ISO standard 11254. Laser conditioning was conducted by scanning the surface of the samples. Results showed that laser damage resistance was enhanced by increasing the oxygen partial pressure during deposition. LIDT of the samples was changed after laser conditioning. Experimental results revealed that there is enhancement of laser damage resistance of the samples with higher oxygen partial pressure after laser conditioning.

  15. Effect of pollution on DNA damage and essential fatty acid profile in Cirrhinus mrigala from River Chenab

    NASA Astrophysics Data System (ADS)

    Hussain, Bilal; Sultana, Tayyaba; Sultana, Salma; Al-Ghanim, K. A.; Mahboob, Shahid

    2016-05-01

    The objective of this study was to evaluate the effect of anthropogenic pollution on DNA damage and the fatty acid profile of the bottom dweller fish (Cirrhinus mrigala), collected from the River Chenab, in order to assess the effect of the toxicants on the quality of the fish meat. The levels of Cd, Hg, Cu, Mn, Zn, Pb, Cr and Sn and of phenols from this river were significantly higher than the permissible limits set by the USEPA. Comet assays showed DNA damage in Cirrhinus mrigala collected from three different sampling sites in the polluted area of the river. Significant differences were observed for DNA damage through comet assay in fish collected from polluted compared to control sites. No significant differences were observed for DNA damage between farmed and fish collected from upstream. The micronucleus assay showed similar trends. Fish from the highly polluted sites showed less number of fatty acids and more saturated fatty acids in their meat compared to fish from less polluted areas. Several fatty acids were missing in fish with higher levels of DNA in comet tail and micronucleus induction. Long-chain polyunsaturated fatty acids, eicosapentaenoic acid (20:5n-3) was found missing in the fish from polluted environment while it was found in considerable amount in farmed fish 7.8±0.4%. Docosahexaenoic acid (22:6n-3) also showed significant differences as 0.1±0.0 and 7.0±0.1% respectively, in wild polluted and farmed fishes.

  16. Effect of inhibitors of arachidonic acid metabolism on efflux of intracellular enzymes from skeletal muscle following experimental damage.

    PubMed Central

    Jackson, M J; Wagenmakers, A J; Edwards, R H

    1987-01-01

    The role of arachidonic acid metabolism in the efflux of intracellular enzymes from damaged skeletal muscle has been examined in vitro using inhibitors of cyclo-oxygenase and lipoxygenase enzymes. Damage to skeletal muscle induced by either calcium ionophore A23187 (25 microM) or dinitrophenol (1 mM) caused an increase in the efflux of prostaglandins E2 and F2 alpha together with a large efflux of intracellular creatine kinase. Use of a cyclo-oxygenase inhibitor completely prevented the efflux of prostaglandins, but had no effect on creatine kinase efflux. However, several agents having the ability to inhibit lipoxygenase enzymes dramatically reduced creatine kinase efflux following damage. These data suggest that a product or products of lipoxygenase enzymes may be mediators of the changes in plasma membrane integrity which permit efflux of intracellular enzymes as a consequence of skeletal muscle damage. PMID:3109374

  17. Cloud acidity and acidic deposition in the lower troposphere and ozone depletion in the Antarctic stratosphere: Modeling and data analysis regarding the role of atmospheric aerosol

    SciTech Connect

    Lin, Nenghuei.

    1991-01-01

    This study focused on the role of atmospheric aerosols in determining the cloud acidity and acidic deposition in the lower troposphere and the ozone depletion in the Antarctic stratosphere. For the former, a cloud chemistry model is developed to study the in-cloud chemistry and acidity in cloud droplets. The cloud chemistry model includes the absorption of trace gases, the oxidation of aqueous phase SO{sub 2}, and the scavenging of atmospheric aerosols. A new scheme is developed to differentiate the acidity and chemical composition distributing in individual cloud droplets. The above cloud chemistry model is incorporated into a two-layer flow model in order to investigate the effects of mountain waves on the cloud acidity. Using the three-year database acquired at Mt. Mitchell site, the in-cloud chemistry and acidic deposition through dry, wet and cloud deposition pathways are investigated. The in-cloud scavenging of submicron aerosols such as sulfates and nitrates is parameterized as a function of cloud deposition rate. The deposition fluxes of sulfur (S) compounds are found primarily contributed by cloud capture mechanism followed by incident precipitation and dry deposition. A comparison of deposition estimates at Mt. Mitchell with those at other sites shows that the sulfate deposition at sites exceeding 1,200 m MSL in elevation in Bavaria (Germany) and eastern USA is almost identical within error limits. The features of the Antarctic stratospheric aerosols during the ozone depletion episode of October 1987 are investigated based on the SAGE 2 (Stratospheric Aerosol and Gas Experiment 2) data. The study focuses on (1) inferring the aerosol size spectrum using a modified randomized minimization-search-technique (RMST), and (2) investigating the vertical, zonal and columnar averages of aerosol properties, together with the ozone concentration.

  18. Thermal and trophic stability of deeper Maine lakes in granite waterhsheds implacted by acid deposition

    SciTech Connect

    Stauffer, R.E.; Wittchen, B.D. )

    1990-09-01

    Acid deposition can lead to lake and watershed acidification, increases in lake transparency, and reduction in thermal stability and hypolimnetic oxygen deficits. On the basis of lake surveys during August-September 1985, we determined to what extent the deeper (maximum depth z{sub m}{gt}17 m) Maine lakes in acid-sensitive granitic watersheds have registered changes in temperature and oxygen stratification, as compared to 1938-1942, when G.P. Cooper performed the earliest scientific surveys of the state's lakes. After correcting for small but geographically consistent interannual differences in summer hypolimnetic temperatures related to spring turnover, and weather-dependent differences in mixed layer depth, there has been no significant change in thermal stratification in these Maine lakes over approximately 43 years. On the basis of specific historical contrasts in the late summer metalimnetic, hypolimnetic, and bathylimnetic oxygen concentrations there has been no significant change in lake trophic state or transparency.

  19. A Martian analog in Kansas: Comparing Martian strata with Permian acid saline lake deposits

    NASA Astrophysics Data System (ADS)

    Benison, Kathleen C.

    2006-05-01

    An important result of the Mars Exploration Rover's (MER) mission has been the images of sedimentary structures and diagenetic features in the Burns Formation at Meridiani Planum. Bedding, cross-bedding, ripple marks, mud cracks, displacive evaporite crystal molds, and hematite concretions are contained in these Martian strata. Together, these features are evidence of past saline groundwater and ephemeral shallow surface waters on Mars. Geochemical analyses of these Martian outcrops have established the presence of sulfates, iron oxides, and jarosite, which strongly suggests that these waters were also acidic. The same assemblage of sedimentary structures and diagenetic features is found in the salt-bearing terrestrial red sandstones and shales of the middle Permian (ca. 270 Ma) Nippewalla Group of Kansas, which were deposited in and around acid saline ephemeral lakes. These striking sedimentological and mineralogical similarities make these Permian red beds and evaporites the best-known terrestrial analog for the Martian sedimentary rocks at Meridiani Planum.

  20. Assessing biogeographic patterns in the changes in soil invertebrate biodiversity due to acidic deposition

    SciTech Connect

    Sugg, P.M.; Kuperman, R.G.; Loucks, O.L. |

    1995-09-01

    We are studying the response of soil faunal communities to a gradient in acidic deposition across midwestern hardwood forests. We have documented a pattern of population decrease and species loss for soil invertebrates along the acidification gradient. We now ask the following question: When confronted with apparent diversity changes along a region-wide pollution gradient, how can one assess the possibility of natural biogeographic gradients accounting for the pattern? As a first approximation, we use published range maps from taxonomic monographs to determine the percent of the regional fauna with ranges encompassing each site. For staphylinid beetles, range data show no sign of a biogeographic gradient. Yet for soil staphylinids, a large decrease is seen in alpha diversity (as species richness) from low to high acid dose sites (from 20 species to 8). Staphylinid species turnover is greatest in the transition from low to intermediate dose sites.

  1. IMPACTS OF ACIDIC DEPOSITION: CONTEXT AND CASE STUDIES OF FOREST SOILS IN THE SOUTHEASTERN U.S.

    EPA Science Inventory

    The authors designed their assessment to include both the basic foundation needed by non-experts and the detailed information needed by experts. Their assessment includes background information on acidic deposition (Chap. 1), an in-depth discussion of the nature of soil acidity a...

  2. EFFECTS OF ACIDIC DEPOSITION ON STREAMS IN THE APPALACHIAN MOUNTAINS AND PIEDMONT REGION OF THE MID-ATLANTIC UNITED STATES

    EPA Science Inventory

    Streams in the Appalachian Mountain area of the Mid-Atlantic receive some of the largest acidic deposition loadings of any region of the United States. ompilation of survey data from the Mid-Appalachians yields a consistent picture of the acid-base status of streams. cidic stream...

  3. Limestone characterization to model damage from acidic precipitation: Effect of pore structure on mass transfer

    USGS Publications Warehouse

    Leith, S.D.; Reddy, M.M.; Irez, W.F.; Heymans, M.J.

    1996-01-01

    The pore structure of Salem limestone is investigated, and conclusions regarding the effect of the pore geometry on modeling moisture and contaminant transport are discussed based on thin section petrography, scanning electron microscopy, mercury intrusion porosimetry, and nitrogen adsorption analyses. These investigations are compared to and shown to compliment permeability and capillary pressure measurements for this common building stone. Salem limestone exhibits a bimodal pore size distribution in which the larger pores provide routes for convective mass transfer of contaminants into the material and the smaller pores lead to high surface area adsorption and reaction sites. Relative permeability and capillary pressure measurements of the air/water system indicate that Salem limestone exhibits high capillarity end low effective permeability to water. Based on stone characterization, aqueous diffusion and convection are believed to be the primary transport mechanisms for pollutants in this stone. The extent of contaminant accumulation in the stone depends on the mechanism of partitioning between the aqueous and solid phases. The described characterization techniques and modeling approach can be applied to many systems of interest such as acidic damage to limestone, mass transfer of contaminants in concrete and other porous building materials, and modeling pollutant transport in subsurface moisture zones.

  4. Corosolic acid inhibits the proliferation of glomerular mesangial cells and protects against diabetic renal damage

    PubMed Central

    Li, Xiao-Qiang; Tian, Wen; Liu, Xiao-Xiao; Zhang, Kai; Huo, Jun-Cheng; Liu, Wen-Juan; Li, Ping; Xiao, Xiong; Zhao, Ming-Gao; Cao, Wei

    2016-01-01

    Diabetic nephropathy (DN) is one of the major complications of diabetes mellitus (DM). This study aimed to explore the effects of corosolic acid (CA) on the renal damage of DM and the mechanisms behind these effects. The renoprotective effect of CA was investigated in type 1 diabetic rats and db/db mice. The kidneys and glomerular mesangial cells (GMCs) were used to study the proliferation of GMCs by immunostaining and MTT assay. Further immunoblotting, siRNA, qPCR analysis, and detecting of NADPH oxidase activity and reactive oxygen species (ROS) generation were performed to explore relevant molecular mechanisms. In CA-treated diabetic animals, diabetes-induced albuminuria, increased serum creatinine and blood urea nitrogen were significantly attenuated, and glomerular hypertrophy, mesangial expansion and fibrosis were ameliorated. Furthermore, CA significantly inhibited proliferation of GMCs and phosphorylation of ERK1/2 and p38 MAPK in both diabetic animals and high glucose (HG)-induced GMCs. CA also normalized Δψm and inhibited HG-induced NADPH oxidase activity, ROS generation and NOX4, NOX2, p22phox and p47phox expression. More importantly, CA inhibited GMC proliferation mediated by NADPH/ERK1/2 and p38 MAPK signaling pathways. These findings suggest that CA exert the protective effect on DN by anti-proliferation resulted from inhibition of p38 MAPK- and NADPH-mediated inactivation of ERK1/2. PMID:27229751

  5. Effect of baicalin on hippocampal damage in kainic acid-induced epileptic mice

    PubMed Central

    Liao, Zheng-Jian; Liang, Ri-Sheng; Shi, Song-Sheng; Wang, Chun-Hua; Yang, Wei-Zhong

    2016-01-01

    The aim of the present study was to determine the effect of baicalin on the expression of miR-497 and its target B-cell lymphoma-2 (Bcl-2) in the hippocampus of kainic acid (KA)-induced epileptic mice. To establish status epilepticus (SE), 0.1 µg/5 µl KA was injected into the lateral cerebral ventricle in mice, which then received an intraperitoneal injection of baicalin (100 mg/kg) after 1 and 8 h. Hematoxylin and eosin staining was used to observe the pathological changes in morphology and neuronal apoptosis was determined by terminal transferase-mediated dUTP nick end-labeling staining. Western blot analysis was used to detect the expression of Bcl-2 and cleaved caspase-3 proteins in the hippocampus, while reverse transcription-quantitative polymerase chain reaction was used to quantify hippocampal miR-497 expression. The results showed that baicalin significantly attenuated neuronal damage and apoptosis in the hippocampus 72 h after SE. In addition, baicalin decreased SE-induced expression of miR-497 and cleaved caspase-3 protein, while upregulating the expression of Bcl-2 protein. In conclusion, the present results suggest that baicalin possesses potent antiapoptotic properties and attenuates hippocampal injury in mice after SE, which may be associated with the downregulation of miR-497 and cleaved caspase-3 and the upregulation of Bcl-2. PMID:27588062

  6. Sequence-specific DNA damage induced by ultraviolet A-irradiated folic acid via its photolysis product.

    PubMed

    Hirakawa, Kazutaka; Suzuki, Hiroyuki; Oikawa, Shinji; Kawanishi, Shosuke

    2003-02-15

    DNA damage mediated by photosensitizers participates in solar carcinogenesis. Fluorescence measurement and high-performance liquid chromatography analysis demonstrated that photoirradiated folic acid, one of the photosensitizers in cells, generates pterine-6-carboxylic acid (PCA). Experiments using 32P-labeled DNA fragments obtained from a human gene showed that ultraviolet A-irradiated folic acid or PCA caused DNA cleavage specifically at consecutive G residues in double-stranded DNA after Escherichia coli formamidopyrimidine-DNA glycosylase or piperidine treatment. The amount of 8-oxo-7,8-dihydro-2(')-deoxyguanosine formed through this DNA photoreaction in double-stranded DNA exceeded that in single-stranded DNA. Kinetic studies suggested that DNA damage is caused mainly by photoexcited PCA generated from folic acid rather than by folic acid itself. In conclusion, photoirradiated folic acid generates PCA, which induces DNA photooxidation specifically at consecutive G residues through electron transfer. Excess intake of folic acid supplements may increase a risk of skin cancer by solar ultraviolet light. PMID:12573286

  7. Interactions of amino acids with oxidized guanine in the gas phase associated with the protection of damaged DNA.

    PubMed

    Zhao, Jing; Yang, Hongfang; Zhang, Meng; Bu, Yuxiang

    2013-04-01

    Density functional theory calculations were employed to study the stabilization process of the guanine radical cation through amino acid interactions as well as to understand the protection mechanisms. On the basis of our calculations, several protection mechanisms are proposed in this work subject to the type of the amino acid. Our results indicate that a series of three-electron bonds can be formed between the amino acids and the guanine radical cation which may serve as relay stations supporting hole transport. In the three-electron-bonded, π-π-stacked, and H-bonded modes, amino acids can protect guanine from oxidation or radiation damage by sharing the hole, while amino acids with reducing properties can repair the guanine radical cation through proton-coupled electron transfer or electron transfer. Another important finding is that positively charged amino acids (ArgH(+), LysH(+), and HisH(+)) can inhibit ionization of guanine through raising its ionization potential. In this situation, a negative dissociation energy for hydrogen bonds in the hole-trapped and positively charged amino acid-Guanine dimer is observed, which explains the low hole-trapping efficiency. We hope that this work provides valuable information on how to protect DNA from oxidation- or radiation-induced damages in biological systems. PMID:23427004

  8. Hatching success in salamanders and chorus frogs at two sites in Colorado, USA: Effects of acidic deposition and climate

    USGS Publications Warehouse

    Muths, E.; Campbell, D.H.; Corn, P.S.

    2003-01-01

    The snowpack in the vicinity of the Mount Zirkel Wilderness Area is among the most acidic in the western United States. We analyzed water chemistry and examined hatching success in tiger salamanders and chorus frogs at ponds there and at nearby Rabbit Ears Pass (Dumont) to determine whether acid deposition affects amphibians or their breeding habitats at these potentially sensitive locations. We found a wide range of acid neutralizing capacity among ponds within sites; the minimum pH recorded during the experiment was 5.4 at one of 12 ponds with all others at pH ??? 5.7. At Dumont, hatching success for chorus frogs was greater in ponds with low acid neutralizing capacity; however, lowest pHs were >5.8. At current levels of acid deposition, weather and pond characteristics are likely more important than acidity in influencing hatching success in amphibian larvae at these sites.

  9. Imbalance in Fatty-Acid-Chain Length of Gangliosides Triggers Alzheimer Amyloid Deposition in the Precuneus

    PubMed Central

    Oikawa, Naoto; Matsubara, Teruhiko; Fukuda, Ryoto; Yasumori, Hanaki; Hatsuta, Hiroyuki; Murayama, Shigeo; Sato, Toshinori; Suzuki, Akemi; Yanagisawa, Katsuhiko

    2015-01-01

    Amyloid deposition, a crucial event of Alzheimer’s disease (AD), emerges in distinct brain regions. A key question is what triggers the assembly of the monomeric amyloid ß-protein (Aß) into fibrils in the regions. On the basis of our previous findings that gangliosides facilitate the initiation of Aß assembly at presynaptic neuritic terminals, we investigated how lipids, including gangliosides, cholesterol and sphingomyelin, extracted from synaptic plasma membranes (SPMs) isolated from autopsy brains were involved in the Aß assembly. We focused on two regions of the cerebral cortex; precuneus and calcarine cortex, one of the most vulnerable and one of the most resistant regions to amyloid deposition, respectively. Here, we show that lipids extracted from SPMs isolated from the amyloid-bearing precuneus, but neither the amyloid-free precuneus nor the calcarine cortex, markedly accelerate the Aß assembly in vitro. Through liquid chromatography-mass spectrometry of the lipids, we identified an increase in the ratio of the level of GD1b-ganglioside containing C20:0 fatty acid to that containing C18:0 as a cause of the enhanced Aß assembly in the precuneus. Our results suggest that the local glycolipid environment play a critical role in the initiation of Alzheimer amyloid deposition. PMID:25798597

  10. Sensitivity of high-elevation streams in the Southern Blue Ridge Province to acidic deposition

    USGS Publications Warehouse

    Winger, P.V.; Lasier, P.J.; Hudy, M.; Fowler, D.; Van Den Avyle, M.J.

    1987-01-01

    The Southern Blue Ridge Province, which encompasses parts of northern Georgia, eastern Tennessee, and western North Carolina, has been predicted to be sensitive to impacts from acidic deposition, owing to the chemical composition of the bedrock geology and soils. This study confirms the predicted potential sensitivity, quantifies the level of total alkalinity and describes the chemical characteristics of 30 headwater streams of this area. Water chemistry was measured five times between April 1983 and June 1984 at first and third order reaches of each stream during baseflow conditions. Sensitivity based on total alkalinity and the Calcite Saturation Index indicates that the headwater streams of the Province are vulnerable to acidification. Total alkalinity and p11 were generally higher in third order reaches (mean, 72 ?eq/? and 6.7) than in first order reaches (64 ?eq/? and 6.4). Ionic concentrations were low, averaging 310 and 340 ?eq/? in first and third order reaches, respectively. A single sampling appears adequate for evaluating sensitivity based on total alkalinity, but large temporal variability requires multiple sampling for the detection of changes in pH and alkalinity over time. Monitoring of stream water should continue in order to detect any subtle effects of acidic deposition on these unique resource systems.

  11. Characterization of thin-film deposition in a pulsed acrylic acid polymerizing discharge

    SciTech Connect

    Voronin, Sergey A.; Bradley, James W.; Fotea, Catalin; Zelzer, Mischa; Alexander, Morgan R.

    2007-07-15

    In this study, thin-film deposition in a pulsed rf polymerizing discharge (13.56 MHz) struck in acrylic acid has been investigated by mass spectrometry, x-ray photoelectron spectroscopy, and quartz crystal microbalance techniques. The experiment was conducted at a fixed acrylic acid pressure of 1.3 Pa and 'on' pulse duration of 0.1 ms, whereas the 'off' time was varied between 0 and 20 ms. The rf input power in the 'on' time and gas flow rate were varied between 10 and 50 W and 1.5 and 4.8 sccm (sccm denotes cubic centimeter per minute at STP), respectively. These changes of the discharge conditions resulted in large-scale progressive variations in film and gas-phase plasma composition. In particular, the -COOH functionality of the monomer was increasingly retained in the plasma-generated thin films as the duty cycle was lowered (i.e., with lowered time-averaged powers). The monomer retention reached its maximum value of 66% for 'off' times exceeding 5 ms, when the discharge was operating in the power-deficient regime. The results show that the film deposition rate is a strong function of the monomer flow rate, whereas -COOH retention is correlated to the amount of unfragmented monomer in the plasma, controlled by the applied power.

  12. Use of Soil-Streamwater Relationships to Assess Regional Patterns of Recovery from Acidic Deposition Effects

    NASA Astrophysics Data System (ADS)

    Siemion, J.; Lawrence, G. B.; Murdoch, P. S.

    2012-12-01

    Declines of acidic deposition levels by as much as 50% since 1990 have led to partial recovery of surface waters in the Northeastern United States, but continued depletion of soil calcium through this same period suggests a disconnection between soil and surface water chemistry. To investigate the role of soil-surface water interactions in recovery from acidification, the first regional survey to directly relate soil chemistry to stream chemistry during high flow was implemented in the Catskill region of New York, where acidic deposition levels are among the highest in the East. More than 40% of streams sampled in the southwestern Catskill Mountains were determined to be acidified with inorganic monomeric aluminum concentrations that exceeded a threshold that is toxic to aquatic biota and more than 80% likely to exceed this threshold during the highest flows, but less than 10% were acidified in the northwestern portion of the region. Median Oa horizon soil base saturation ranged from 50-80% across the region, but median base saturation in the upper 10cm of the B horizon was less than 20% across the region and was only 2% in the southwestern area. Therefore, aluminum is likely to be interfering with calcium uptake in the mineral horizon by trees in half the watersheds where soils were collected. These results indicate stream chemistry over the Catskill region does not reflect the calcuim depletion of the B horizon that our sampling suggests is ubiquitous throughout the region.

  13. Stretchability of Silver Films on Thin Acid-Etched Rough Polydimethylsiloxane Substrates Fabricated by Electrospray Deposition

    NASA Astrophysics Data System (ADS)

    Mehdi, S. M.; Cho, K. H.; Kang, C. N.; Choi, K. H.

    2015-07-01

    This paper investigates the fabrication of Ag films through the electrospray deposition (ESD) technique on sub-millimeter-thick acid-etched rough polydimethylsiloxane (PDMS) substrates having both low and high modulus of elasticity. The main focus of the study is on the stretchable behavior of ESD-deposited Ag nanoparticles-based thin films on these substrates when subjected to axial strains. Experimental results suggest that the as-fabricated films on thin acid-etched rough low modulus PDMS has an average stretchability of 5.6% with an average increase in the resistance that is 23 times that of the initial resistance at electrical failure (complete rupture of the films). Comparatively, the stretchability of Ag films on the high modulus PDMS was found to be 3 times higher with 4.65 times increase in the resistance at electrical failure. Also, a high positive value of the piezoresistive coefficient for these films suggests that the resistivity changes during stretching, and thus deviation from the simplified models is inevitable. Based on these results, new models are presented that quantify the changes in resistance with strain.

  14. nC60 deposition kinetics: the complex contribution of humic acid, ion concentration, and valence.

    PubMed

    McNew, Coy P; LeBoeuf, Eugene J

    2016-07-01

    The demonstrated toxicity coupled with inevitable environmental release of nC60 raise serious concerns about its environmental fate and transport, therefore it is crucial to understand how nC60 will interact with subsurface materials including attached phase soil and sediment organic matter (AP-SOM). This study investigated the attachment of nC60 onto a Harpeth humic acid (HHA) coated silica surface under various solution conditions using a quartz crystal microbalance with dissipation monitoring. The HHA coating greatly enhanced nC60 attachment at low ion concentrations while hindering attachment at high ion concentrations in the presence of both mono and divalent cations. At low ion concentrations, the HHA greatly reduced the surface potential of the silica, enhancing nC60 deposition through reduction in the electrostatic repulsion. At high ion concentrations however, the reduced surface potential became less important due to the near zero energy barrier to deposition and therefore non-DLVO forces dominated, induced by compaction of the HHA layer, and leading to hindered attachment. In this manner, observed contributions from the HHA layer were more complex than previously reported and by monitoring surface charge and calculated DLVO interaction energy alongside attachment experiments, this study advances the mechanistic understanding of the variable attachment contributions from the humic acid layer. PMID:27061365

  15. Heavy metals and acidic components in total deposited matter in Sibenik and National Park Kornati, Croatia.

    PubMed

    Cacković, Mirjana; Kalinić, Natasa; Vadjić, Vladimira; Pehnec, Gordana

    2009-01-01

    This article presents the results of 6 years (1999-2004) of monitoring acidic components (fluoride, chloride, nitrate, sulfate) and heavy metals (lead, cadmium, thallium) in total deposited matter (TDM) in the town of Sibenik and the National Park Kornati, Croatia, in order to determine their levels, spatial and temporal variations, and possible emission source. Bulk deposition samples were collected using the Bergerhoff samplers. TDM matter was determined gravimetrically. Acidic anions were analyzed using ion chromatography. Metallic components were determined by atomic absorption spectrometry. Results show that the levels of measured pollutants were relatively low compared to those reported in other investigations. Statistical analysis indicates that the measured pollutants originate from several sources such as resuspended soil, industry, road dust, traffic, and secondary aerosols as the most important. The levels of TDM show a slightly increasing trend at all sampling sites. A significant increasing trend in the levels of nitrate and sulfate in TDM could be the consequence of increasing traffic activity and urbanization. The significant increasing trend in the ratio between nitrate and sulfate in TDM indicates that the nitrate and sulfate relative contribution to acidification is increasing. The level of heavy metals in TDM was in order of lead > thallium > cadmium at all sampling sites with slightly decreasing trend. PMID:18414927

  16. Growth characteristics of Ti-based fumaric acid hybrid thin films by molecular layer deposition.

    PubMed

    Cao, Yan-Qiang; Zhu, Lin; Li, Xin; Cao, Zheng-Yi; Wu, Di; Li, Ai-Dong

    2015-09-01

    Ti-based fumaric acid hybrid thin films were successfully prepared using inorganic TiCl4 and organic fumaric acid as precursors by molecular layer deposition (MLD). The effect of deposition temperature from 180 °C to 350 °C on the growth rate, composition, chemical state, and topology of hybrid films has been investigated systematically by means of a series of analytical tools such as spectroscopic ellipsometry, atomic force microscopy (AFM), high resolution X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The MLD process of the Ti-fumaric acid shows self-limiting surface reaction with a reasonable growth rate of ∼0.93 Å per cycle and small surface roughness of ∼0.59 nm in root-mean-square value at 200 °C. A temperature-dependent growth characteristic has been observed in the hybrid films. On increasing the temperature from 180 °C to 300 °C, the growth rate decreases from 1.10 to 0.49 Å per cycle and the XPS composition of the film's C : O : Ti ratio changes from 8.35 : 7.49 : 1.00 to 4.66 : 4.80 : 1.00. FTIR spectra indicate that the hybrid films show bridging bonding mode at a low deposition temperature of 200 °C and bridging/bidentate mixed bonding mode at elevated deposition temperatures of 250 and 300 °C. The higher C and O amounts deviating from the ideal composition may be ascribed to increased organic incorporation into the hybrid films at lower deposition temperature and temperature-dependent density of reactive sites (-OH). The composition of hybrid films grown at 350 °C shows a dramatic decrease in C and O elemental composition (C : O : Ti = 1.97 : 2.76 : 1.00) due to the thermal decomposition of the fumaric acid precursor. The produced by-product H2O changes the structure of the hybrid films, resulting in the formation of more Ti-O bonds at high temperatures. The stability of the hybrid films against chemical and thermal treatment, and long-term storage by

  17. How laser damage resistance of HfO2/SiO2 optical coatings is affected by embedded contamination caused by pausing the deposition process

    NASA Astrophysics Data System (ADS)

    Field, Ella; Bellum, John; Kletecka, Damon

    2015-07-01

    Reducing contamination is essential for producing optical coatings with high resistance to laser damage. One aspect of this principle is to make every effort to limit long interruptions during the coating's deposition. Otherwise, contamination may accumulate during the pause and become embedded in the coating after the deposition is restarted, leading to a lower laser-induced damage threshold (LIDT). However, pausing a deposition is sometimes unavoidable, despite our best efforts. For example, a sudden hardware or software glitch may require hours or even overnight to solve. In order to broaden our understanding of the role of embedded contamination on LIDT, and determine whether a coating deposited under such non-ideal circumstances could still be acceptable, this study explores how halting a deposition overnight impacts the LIDT, and whether ion cleaning can be used to mitigate any negative effects on the LIDT. The coatings investigated are a beam splitter design for high reflection at 1054 nm and high transmission at 527 nm, at 22.5° angle of incidence in S-polarization. LIDT tests were conducted in the nanosecond regime.

  18. Response of DOC in Acid-Sensitive Maine Lakes to Decreasing Sulfur Deposition (1993 - 2009)

    NASA Astrophysics Data System (ADS)

    Oelsner, G. P.; Sanclements, M.; McKnight, D. M.; Stoddard, J. L.

    2010-12-01

    In response to the Clean Air Act Amendments of 1990, sulfur deposition has decreased across the northeastern United States. As a result, sulfate concentrations in lakes and streams have also decreased and many surface waters have become less acidic. Over the same time period, there has been a concurrent increase in dissolved organic carbon (DOC) concentrations in many lakes and streams which has been difficult to interpret. To assess the biogeochemical processes driving increasing DOC concentrations we analyzed archived samples from 9 acid-sensitive lakes in Maine collected between 1993 and 2009 using UV-Vis and fluorescence spectroscopy. The fluorescence index (FI) was calculated for all samples. The FI represents the ratio of the emission intensity at 450 nm to 550 nm at an excitation wavelength of 370 nm and provides information regarding the source of dissolved organic matter (DOM). This index has a value of approximately 1.9 for microbially derived fluvic acids and a value of approximately 1.4 for terrestrially (higher-plant) derived fluvic acids. All four lakes with increasing DOC trends had concomitant decreases in the FI index. Two of five lakes with no significant DOC trend also demonstrated no trend in FI values over time, while three lakes revealed a decrease in FI values. To confirm that the FI measured in whole water was primarily reflective of fulvic acids (FA), XAD-resin was used to isolate FA from a subset of samples. Analysis of the FA indicates that the FI values for the humic substances are slightly higher, yet well correlated with whole water samples. This suggests that despite prolonged storage in plastic, the FI trends are meaningful. The FI trends suggest a terrestrial source for the increasing DOC and may be driven by increased DOM production from soils experiencing decreased acid loading. Decreases in sulfate deposition can increase soil pH and soil organic matter solubility, as well as decrease the ionic strength of the soil solution, and

  19. Relationships between soil properties and community structure of soil macroinvertebrates in oak-history forests along an acidic deposition gradient

    SciTech Connect

    Kuperman, R.G.

    1996-02-01

    Soil macroinvertebrate communities were studied in ecologically analogous oak-hickory forests across a three-state atmospheric pollution gradient in Illinois, Indiana, and Ohio. The goal was to investigate changes in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the possible relationships between these changes and physico-chemical properties of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiated pattern of soil macroinvertebrate fauna seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroinvertebrates with soil parameters suggest that their populations could have been affected by acidic deposition in the region. Abundance of total soil macroinvertebrates decreased with the increased cumulative loading of acidic deposition. Among the groups most sensitive to deposition were: earthworms gastropods, dipteran larvae, termites, and predatory beetles. The results of the study support the hypothesis that chronic long-term acidic deposition could aversely affect the soil decomposer community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high deposition sites.

  20. Responses of 20 lake-watersheds in the Adirondack region of New York to historical and potential future acidic deposition.

    PubMed

    Zhou, Qingtao; Driscoll, Charles T; Sullivan, Timothy J

    2015-04-01

    Critical loads (CLs) and dynamic critical loads (DCLs) are important tools to guide the protection of ecosystems from air pollution. In order to quantify decreases in acidic deposition necessary to protect sensitive aquatic species, we calculated CLs and DCLs of sulfate (SO4(2-))+nitrate (NO3-) for 20 lake-watersheds from the Adirondack region of New York using the dynamic model, PnET-BGC. We evaluated lake water chemistry and fish and total zooplankton species richness in response to historical acidic deposition and under future deposition scenarios. The model performed well in simulating measured chemistry of Adirondack lakes. Current deposition of SO4(2-)+NO3-, calcium (Ca2+) weathering rate and lake acid neutralizing capacity (ANC) in 1850 were related to the extent of historical acidification (1850-2008). Changes in lake Al3+ concentrations since the onset of acidic deposition were also related to Ca2+ weathering rate and ANC in 1850. Lake ANC and fish and total zooplankton species richness were projected to increase under hypothetical decreases in future deposition. However, model projections suggest that lake ecosystems will not achieve complete chemical and biological recovery in the future. PMID:25544337

  1. Chemical and biological status of lakes and streams in the upper midwest: assessment of acidic deposition effects

    USGS Publications Warehouse

    Wiener, J.G.; Eilers, J.M.

    1987-01-01

    Many lakes in three areas in the Upper Midwest - northeastern Minnesota, northern Wisconsin, and the Upper Peninsula of Michigan - have low acid neutralizing capacity (ANC) and may be susceptible to change by acidic deposition. Northcentral Wisconsin and the Upper Peninsula of Michigan together contain about 150-300 acidic lakes (ANC ≤ 0), whereas none have been found in Minnesota. These acidic lakes are precipitation-dominated, Clearwater seepage lakes having small surface area, shallow depth, and low concentrations of dissolved organic carbon. The spatial distribution of these acidic lakes parallels a west to east gradient of increasing sulfate and hydrogen ion deposition. Several of these acidic lakes exhibit chemical characteristics and biological changes consistent with those observed elsewhere in waters reported to be acidified by acidic deposition. However, an hypothesis of recent lake acidification is not supported by analyses of either historical chemical data or diatom remains in lake sediments, and natural sources of acidity and alternative ecological processes have not been conclusively eliminated as causative factors. Streams in this three-state region have high ANC and appear to be insensitive to acidic deposition. The species richness and composition of lacustrine fish communities in the region are partly related to pH and associated chemical factors. Sport fishes considered acid-sensitive and of primary concern with regard to acidification include walleye, smallmouth bass, and black crappie. The fishery in at least one lake, Morgan Lake in Wisconsin (pH 4.6), may have declined because of acidification. Given the general lack of quantitative fishery data for acidic Wisconsin and Michigan lakes, however, more general conclusions concerning impacts or the absence of impacts of acidification on the region's fishery resources are not possible.

  2. Analysis of southeastern Canada lake-water chemistry data in relation to acidic deposition

    SciTech Connect

    Olson, R.J.; Cook, R.B.; Ross-Todd, B.M.; Beauchamp, J.J.

    1990-05-01

    Lake-water chemistry data were obtained for lakes in southeastern Canada to study relationships between atmospheric deposition and acid-base chemistry as part of the National Acid Precipitation Assessment Program State of Science and Technology reports. Quality assurance checks were made to ensure that the data used were of sufficient quality and were comparable to data from the United States. Ninety-eight percent of the 8506 sampled lakes had pH, ANC, and SO{sub 4}{sup 2 {minus}} data and were used in our analyses. Of these, we created a subset of 4017 lakes having data for more variable (Ca{sup 2+}, Mg{sup 2+}, Na{sup +}, K{sup +}, DOC, and conductivity) to analyze potential sources of lake-water acidity. The objectives of this work were to determine the geographical extent and number of potentially affected systems and to infer causes of acidification based on ion ratios. 35 refs., 28 figs., 12 tabs.

  3. Acidification and recovery of a Spodosol BS horizon from acidic deposition

    SciTech Connect

    Dahlgren, R.A.; McAvoy, D.C.; Driscoll, C.T.

    1990-01-01

    A laboratory study was conducted to examine acidification and recovery of a Spodosol Bs horizon from acidic deposition in the Bear Brook Watershed (BBW) in central Maine. A mechanical vacuum extractor was used to draw solutions through a soil column at three treatments containing 40, 100, or 160 micromol/L SO4(2-). Following 44 d of leaching, all treatments were decreased to the 40 micromol/L SO4(2-) level to examine recovery from acidification. Acidic additions were initially neutralized by release of basic cations and sulfate adsorption. Following attainment of steady state conditions for basic cations and SO4(2-) with respect to the soil adsorption complex, Al dissolution was the primary neutralization mechanism. Aqueous Al activities appeared to be regulated by equilibrium with an Al(OH)3 mineral phase. Following decreases in acid loadings, recovery was rapid resulting in retention of basic cations, reversible release of SO4(2-) and a marked reduction in the concentrations of soluble Al.

  4. Acidification and recovery of a spodosol Bs horizon from acidic deposition

    SciTech Connect

    Dahlgren, R.A.; McAvoy, D.C.; Driscoll, C.T. )

    1990-04-01

    A laboratory study was conducted to examine acidification and recovery of a Spodosol Bs horizon from acidic deposition in the Bear Brook Watershed (BBW) in central Maine. A mechanical vacuum extractor was used to draw solutions through a soil column at three treatments containing 40, 100, or 160 {mu}mol/L SO{sub 4}{sup 2{minus}}. Following 44 days of leaching, all treatments were decreased to the 40 {mu}mol/L SO{sub 4}{sup 2{minus}} level to examine recovery from acidification. Acid additions were initially neutralized by release of basic cations and sulfate adsorption. Following attainment of steady-state conditions for basic cations and SO{sub 4}{sup 2{minus}} with respect to the soil adsorption complex, Al dissolution was the primary neutralization mechanism. Aqueous Al activities appeared to be regulated by equilibrium with an Al(OH){sub 3} mineral phase. Following decreases in acid loadings, recovery was rapid resulting in retention of basic cations, reversible release of SO{sub 4}{sup 2{minus}}, and a marked reduction in the concentrations of soluble Al.

  5. Liquid methionine hydroxy analog (free acid) and DL-methionine attenuate calcium-induced kidney damage in domestic fowl.

    PubMed

    Wideman, R F; Ford, B C; Leach, R M; Wise, D F; Robey, W W

    1993-07-01

    To evaluate the possibility that kidney damage may be induced by the commercial practice of feeding high-Ca (HCa) prelayer rations, and to evaluate the protective efficacy of supplementing HCa diets with liquid methionine hydroxy analog free acid or DL-methionine, 12-wk-old female Single Comb White Leghorn pullets were fed one of the following corn-soybean meal-based diets until they reached 22 wk of age: normal-Ca (NC, 1% Ca); HCa (HC, 3.5% Ca); HCa supplemented with .34 or .68% liquid methionine hydroxy analog free acid (HC3A or HC6A); or HCa supplemented with .3 or .6% DL-methionine (HC3DL or HC6DL). The unsupplemented HC diet caused a significant reduction in kidney mass and a significant increase in the incidence of gross kidney damage and urolithiasis in pullets necropsied at 22 wk of age. Calcium-induced kidney damage was attenuated in a dose-response fashion by supplementing the HC diet with liquid methionine hydroxy analog and DL-methionine. None of the diets caused a significant metabolic acidosis. Plasma uric acid concentrations were not predictive of the extent of Ca-induced kidney damage. Analyses of glomerular size distributions indicated that subclinical or "hidden" kidney damage may not progressively develop into urolithiasis as hens mature. When compared with hens reared on the NC diet, rearing hens on the HC, HC3A, HC3DL, HC6A, or HC6DL diets did not consistently affect hen-day egg production, egg mass, eggshell mass, percentage eggshell, or bone mineralization. PMID:8346150

  6. Early indications of soil recovery from acidic deposition in U.S. red spruce forests

    USGS Publications Warehouse

    Lawrence, Gregory B.; Shortle, Walter C.; David, Mark B.; Smith, Kevin T.; Warby, Richard A.F.; Lapenis, Andrei G.

    2012-01-01

    Forty to fifty percent decreases in acidic deposition through the 1980s and 1990s led to partial recovery of acidified surface waters in the northeastern United States; however, the limited number of studies that have assessed soil change found increased soil acidification during this period. From existing data, it's not clear whether soils continued to worsen in the 1990s or if recovery had begun. To evaluate possible changes in soils through the 1990s, soils in six red spruce (Picea rubens Sarg.) stands in New York, Vermont, New Hampshire, and Maine, first sampled in 1992 to 1993, were resampled in 2003 to 2004. The Oa-horizon pH increased (P 42−, which decreased the mobility of Al throughout the upper soil profile. Results indicate a nascent recovery driven largely by vegetation processes.

  7. Simulation of acid mine drainage generation around Küre VMS Deposits, Northern Turkey

    NASA Astrophysics Data System (ADS)

    Demirel, Cansu; Kurt, Mehmet Ali; Çelik Balci, Nurgül

    2015-04-01

    experiments with mixed acidophiles at higher temperatures. Further depleted Fe(III) values coinciding with decreasing pH may point to precipitation of secondary phases (i.e. jarosite). This study revealed that the metals (Fe, Cu, Co and Zn) released during short term leaching of the ore (34 days) are generally caused by acid produced by dissolution reactions rather than oxidation. In the long term experiments a more complex biogeochemical reactions (oxidation and dissolution) take place in conjunction. Key words: Bioleaching, AMD, heavy metal release, environment, acidophilic bacteria, Küre copper ore deposits, volcanogenic massive sulfide deposits

  8. Environmental factors affecting the low temperature isomerization of homohopanes in acidic peat deposits, central China

    NASA Astrophysics Data System (ADS)

    Huang, Xianyu; Meyers, Philip A.; Xue, Jiantao; Gong, Linfeng; Wang, Xinxin; Xie, Shucheng

    2015-04-01

    Progressively more evidence reveals the abundant occurrence of the C31 homohopane with a 17α, 21β-configuration (C31 αβ) in immature peats. This compound is commonly considered to be an indicator of thermal maturity in petroleum source rocks, but in peats it has also been interpreted to reflect the oxidation and subsequent decarboxylation reactions of bacteriohopanepolyols with microbially mediated epimerization at C-17 that is catalyzed by the acidic peat conditions. To learn more about the environmental factors that affect the low-temperature isomerization of homohopanes, we investigated the distribution patterns of homohopanes in a well-studied peat core from the Dajiuhu peatland, central China, together with data from modern surface peat samples from Dajiuhu and three other locations. From comparison with paleotemperature and paleohydrologic records in the peat core, we hypothesize that the ratio of C31 αβ hopane relative to the ββ isomer (C31 αβ/ββ) is mainly influenced on a centennial to millennial timescale by ambient temperature with a secondary effect from redox conditions that are defined by peatland water levels. The surface peat samples revealed that relatively high C31 αβ/ββ values occurred under pH < 6. These results suggest that pH is indeed an important factor in the low-temperature isomerization of C31 homohopanes, although the magnitude of the pH effect may be less than those of ambient temperature and redox conditions. In both surface peat and peat horizons from the Dajiuhu peatland, the amount of the C31 αβ compound with R configuration relative to that with S configuration (C31 R/S) varied closely with C31 αβ/ββ, suggesting that the epimerization at both C-17 and C-22 may happen synchronously and at similar rates. This study reveals that the isomerization of homohopanes has the potential to reflect paleoenvironmental changes in acidic peat deposits. In addition, acidic peat samples investigated in this and previous studies

  9. Sulfuric acid karst and its relationship to hydrocarbon reservoir porosity, native sulfur deposits, and the origin of Mississippi Valley-type ore deposits

    SciTech Connect

    Hill, C.A. , Albuquerque, NM )

    1993-03-01

    The Delaware Basin of southeastern New Mexico and West Texas contains hydrocarbons and native sulfur in the basin and sulfuric acid-formed caves and Mississippi Valley-type (MVT) ore deposits around the margins of the basin. Hydrocarbons reacting with sulfate evaporite rock produced hydrogen sulfide gas, which gas oxidized to native sulfur in the basin and which gas also migrated from basin to reef and accumulated there in structural and stratigraphic traps. In the reduced zone of the carbonate reef margin the H[sub 2]S combined with metal-chloride complexes to form MVTs, and in the oxidized zone later in time the H[sub 2]S formed sulfuric acid which dissolved out the famous caves of the region (e.g., Carlsbad Cavern, Lechuguilla Cave). Sulfuric acid karst can be recognized by the discontinuity, large size, and spongework nature of its cave passages, and by the presence of native sulfur, endellite, and large gypsum deposits within these caves. Sulfuric acid oilfield karst refers to cavernous porosity filled with hydrocarbons and can be produced by the mixing of waters of different H[sub 2]S content or by the oxidation of H[sub 2]S to sulfuric acid. Sulfur and carbon-oxygen isotopes have been used to establish and trace the sequence of related hydrocarbon, sulfur, MVT, and karst events in the Delaware Basin.

  10. Post-depositional migration and preservation of methanesulfonic acid (MSA) in polar ice cores

    NASA Astrophysics Data System (ADS)

    Osman, M.; Marchal, O.; Guo, W.; Das, S. B.; Evans, M. J.

    2015-12-01

    Methanesulfonic acid (MSA; CH3SO3-) in ice cores is a unique, high-resolution proxy of regional sea ice behavior, marine primary productivity, and synoptic climatology. Significant uncertainties remain, however, in both our understanding of the production and transfer of MSA to the ice sheet, as well as its preservation over time, compromising the paleoclimatological utility of the proxy. Here we apply a numerical modeling approach to quantitatively investigate the post-depositional processes affecting MSA migration and preservation within the firn and ice column, building on recent observational and theoretical studies. Our model allows us to evaluate the timing and magnitude of the vertical movement of MSA in response to varying influences, including the competing effects of 1) concentration gradients of sea-salts typically deposited asynchronously to MSA, 2) snow accumulation and densification rates, and 3) in situ temperature gradients. We first test the model against a recently collected ice core from a high accumulation site in coastal West Antarctica, where monthly-resolved MSA records show an abrupt shift from a summer-to-winter maximum in MSA at ~23m depth (ρ ≈ 650 kg/m3), near the firn-ice transition. We find our model to be a robust predictor of the observed migrational features in this record, capturing both (i) the abrupt shift in summer-to-winter maximal concentrations of MSA (steady state ≈ 3.2 yrs), and (ii) the depression of the seasonal amplitude at depth. Further, our modeling results suggest post-depositional effects can lead to substantial interannual alteration of the MSA signal, contrary to previous assumptions that MSA migration is confined within annual layers at high accumulation sites. Using a broad range of polar MSA records and their associated, site-specific environmental conditions, we will evaluate the fidelity of subannual to interannual variability of MSA records and systematically determine the factors conducive to its

  11. Could humic acid relieve the biochemical toxicities and DNA damage caused by nickel and deltamethrin in earthworms (Eisenia foetida)?

    PubMed

    Shen, Chen-Chao; Shen, Dong-Sheng; Shentu, Jia-Li; Wang, Mei-Zhen; Wan, Ming-Yang

    2015-12-01

    The aim of the study was to determine whether humic acid (HA) prevented gene and biochemical toxic effects in earthworms (Eisenia foetida) exposed to nickel and deltamethrin (at 100 and 1 mg kg(-1), respectively) in soil. Cellular- and molecular-level toxic effects of nickel and deltamethrin in earthworms were evaluated by measuring damage to lipid membranes and DNA and the production of protein carbonyls over 42 days of exposure. Nickel and deltamethrin induced significant levels of oxidative stress in earthworms, increasing the production of peroxidation products (malondialdehyde and protein carbonyls) and increasing the comet assay tail DNA% (determined by single-cell gel electrophoresis). DNA damage was the most sensitive of the three indices because it gave a higher sample/control ratio than did the other indices. The presence of HA alleviated (in decreasing order of effectiveness) damage to DNA, proteins, and lipid membranes caused by nickel and deltamethrin. A low HA dose (0.5-1% HA in soil) prevented a great deal of lipid membrane damage, but the highest HA dose (3% HA in soil) prevented still more DNA damage. However, the malondialdehyde concentrations in earthworms were higher at the highest HA dose than at the lower HA doses. The amounts of protein carbonyls produced at different HA doses were not significantly different. The toxic effects to earthworms caused by increased oxidizable nickel concentrations could be relieved by adding HA. PMID:26511644

  12. Patterns of acid deposition variability in the Eastern United States, 1981-84

    USGS Publications Warehouse

    Lins, H.F.; Lanfear, K.J.; Schertz, T.L.

    1987-01-01

    An increase in pH and a decrease in sulfate concentration of precipitation were recorded at National Atmospheric Deposition Program and National Trends Network (NADP/NTN) monitoring sites in the Eastern United States between 1981 and 1984. The decline in acidity, however, was not spatially or temporally uniform. The range in acidity and sulfate concentrations decreased during the four-yr period. Variations in the area of constant pH surfaces take the general form of area reductions in both the lower (pH 4.01-4.40) and upper (pH 4.91-5.40) range of values with concomitant area increases in the middle (pH 4.41-4.90) range. The pattern for sulfate is simpler, with area increases occurring in the lower (1.0-1.9 mg/L) range, decreases in the upper (2.5-4.4 mg/L) range, with approximate stability in the middle (2.0-2.4 mg/L) range of values. (Author 's abstract)

  13. Acid deposition in the Athabasca Oil Sands Region: a policy perspective.

    PubMed

    Whitfield, Colin J; Watmough, Shaun A

    2015-12-01

    Industrial emissions of sulphur (S) and nitrogen (N) to the atmosphere associated with the oil sands industry in north-eastern Alberta are of interest as they represent the largest localized source in Canada (with potential for future growth) and the region features acid-sensitive upland terrain. Existing emission management policy for the Regional Municipality of Wood Buffalo, where the industry is located, is based on a time-to-effect approach that relies on dynamic model simulations of temporal changes in chemistry and features highly protective chemical criteria. In practice, the policy is difficult to implement and it is unlikely that a scientifically defensible estimate of acidification risk can be put forward due to the limitations primarily associated with issues of scale, chemical endpoint designation (selection of chemical limit for ecosystem protection from acidification) and data availability. A more implementable approach would use a steady-state critical load (CL) assessment approach to identify at-risk areas. The CL assessment would consider areas of elevated acid deposition associated with oil sands emissions rather than targeted political jurisdictions. Dynamic models should only be (strategically) used where acidification risk is identified via CL analysis, in order to characterize the potential for acidification-induced changes that can be detrimental to sensitive biota within the lifespan of the industry. PMID:26607154

  14. Endothelial cell damage after gamma-irradiation in vitro: impaired uptake of alpha-aminoisobutyric acid. [137Cs

    SciTech Connect

    Kwock, L.; Douglas, W.H.; Lin, P.S.; Baur, W.E.; Fanburg, B.L.

    1982-01-01

    The effects of gamma-irradiation with a cesium-137 source were assessed on endothelial cells isolated from bovine pulmonary arteries and maintained in culture. The radiobiologic parameters that characterize the dose-response survival curve for these cells, expressed as mean +/- SD were found to be n . 1.6 +/- 0.2, Dq . 71 +/- 13 rads, and Do . 161 +/- 35 rads, indicating a relatively low capacity of these cells to accumulate or repair radiation damage. Increasing doses of radiation led to decreasing uptake by endothelial cells of (14C)2-aminoisobutyric acid (AIB), a Na+-dependent and nonmetabolizable amino acid. A dose of 500 rads, which caused marked inhibition of cell survival, resulted in a 45% decrease in AIB uptake at 6 h and a 69% decrease in uptake at 24 h after irradiation. No morphologic abnormality was noted in these cells by light microscopy at 24 h after this dose of radiation. Bovine pulmonary artery fibroblasts, on the other hand, showed no significant impairment in uptake of AIB 24 h after exposure to doses of radiation as high as 5,000 rads. The uptake by endothelial cells of (14C)1-aminocyclopentane-1-carboxylic acid, an amino acid transported by a Na+-independent process, was not influenced by 5,000 rads of radiation. Our studies show that endothelial cells are sensitive to radiation and that impaired Na+-dependent uptake of AIB represents an early event in radiation damage to the endothelial cell.

  15. Prevention of UV-induced skin damages by 11,14,17-eicosatrienoic acid in hairless mice in vivo.

    PubMed

    Jin, Xing-Ji; Kim, Eun Ju; Oh, In Kyung; Kim, Yeon Kyung; Park, Chi-Hyun; Chung, Jin Ho

    2010-06-01

    Polyunsaturated fatty acids (PUFAs) are known to play important roles in various physiological and pathological processes. Recent studies have shown that some omega-3 (omega-3) PUFAs, such as eicosapentaenoic acid (EPA) and dodecahexaenoic acid (DHA), have protective effects on acute and chronic UV-induced changes. However, the effects of other omega-3 PUFAs including 11,14,17-eicosatrienoic acid (20:3) (ETA) on UV-induced skin damages are poorly understood. In this study, we investigated the cutaneous photoprotective effects of ETA in hairless mice in vivo. Female HR-1 hairless mice were topically treated with vehicle (ethanol:polyethylene glycol=30:70) only, 0.1% ETA, or 1% ETA once a day for 3 successive days after one time UV irradiation (200 mJ/cm(2)) on dorsal skins. Skin biopsy was carried out on the fourth day (72 hr after UV irradiation). We found that topical treatment with ETA attenuated UV-induced epidermal and dermal thickness and infiltration of inflammatory cells, and impairment of skin barrier function. In addition, ETA suppressed the expression of IL-1beta, COX-2, and MMP-13 induced by UV irradiation. Our results show that the topical application of ETA protects against UV-induced skin damage in hairless mice and suggest that ETA can be a potential agent for preventing and/or treating UV-induced inflammation and photoaging. PMID:20514317

  16. Reactive Iron deposition and ground water inflow control neutralization processes in acidic mine lakes

    NASA Astrophysics Data System (ADS)

    Blodau, C.

    2002-12-01

    The controls on the internal neutralization of highly acidified waters by iron sulphide accumulation are yet poorly understood. To elucidate the influence of ground water inflow on neutralization processes, inventories of solid phase iron and sulphur, pore water profiles and rates of ferrous iron and sulphate production and consumption were analyzed in different areas of an acidic mine lake. Ground water inflow had previously been determined by ground water modelling and chamber measurements (Knoll et al., 1999). The investigated sediments adjacent to mine tailings, which were subject to the inflow of groundwater (10-30 L d-1 m-2), were richer in dissolved ferrous iron iron (30 vs. 5 mmol L-1) and sulphate (30 vs. 10 mmol L-1) and showed higher pH values (6 vs. 4) than the sediments in areas of the lake not being influenced by groundwater inflow. Sediments adjacent to the mine tailings also showed higher rates of sulphate reduction and iron sulphide accumulation (Fig. 1). From these data it is suggested that neutralization processes in iron rich, acidic mine lakes neutralization processes primarily occur in areas influenced by the inflow of acid mine groundwater. These waters usually have considerably higher pH values than the surface waters in the lakes due to buffering processes in the tailings. The seepage of this water through the sediment might thus lead to higher pH values and thus to a higher thermodynamic competitiveness of sulfate reduction vs. iron reduction (Blodau and Peiffer 2002). This causes increased neutralization rates. These findings have consequences for remediation measures in highly acidic lakes. In areas influenced by the inflow of mine drainage increases in carbon availability, for example by the deposition of particulate organic matter, should enhance iron sulphide formation rates, whereas in other areas increases in carbon availability would only result in enhanced rates of iron reduction without a lasting gain in alkalinity. Blodau, C

  17. Wetlands serve as natural sources for improvement of stream ecosystem health in regions affected by acid deposition

    USGS Publications Warehouse

    Pound, Katrina L; Lawrence, Gregory B.; Passy, Sophia I.

    2013-01-01

    For over 40 years, acid deposition has been recognized as a serious international environmental problem, but efforts to restore acidified streams and biota have had limited success. The need to better understand the effects of different sources of acidity on streams has become more pressing with the recent increases in surface water organic acids, or 'brownification' associated with climate change and decreased inorganic acid deposition. Here, we carried out a large scale multi-seasonal investigation in the Adirondacks, one of the most acid-impacted regions in the United States, to assess how acid stream producers respond to local and watershed influences and whether these influences can be used in acidification remediation. We explored the pathways of wetland control on aluminum chemistry and diatom taxonomic and functional composition. We demonstrate that streams with larger watershed wetlands have higher organic content, lower concentrations of acidic anions, and lower ratios of inorganic to organic monomeric aluminum, all beneficial for diatom biodiversity and guilds producing high biomass. Although brownification has been viewed as a form of pollution, our results indicate that it may be a stimulating force for biofilm producers with potentially positive consequences for higher trophic levels. Our research also reveals that the mechanism of watershed control of local stream diatom biodiversity through wetland export of organic matter is universal in running waters, operating not only in hard streams, as previously reported, but also in acid streams. Our findings that the negative impacts of acid deposition on Adirondack stream chemistry and biota can be mitigated by wetlands have important implications for biodiversity conservation and stream ecosystem management. Future acidification research should focus on the potential for wetlands to improve stream ecosystem health in acid-impacted regions and their direct use in stream restoration, for example, through

  18. Wetlands serve as natural sources for improvement of stream ecosystem health in regions affected by acid deposition.

    PubMed

    Pound, Katrina L; Lawrence, Gregory B; Passy, Sophia I

    2013-09-01

    For over 40 years, acid deposition has been recognized as a serious international environmental problem, but efforts to restore acidified streams and biota have had limited success. The need to better understand the effects of different sources of acidity on streams has become more pressing with the recent increases in surface water organic acids, or 'brownification,' associated with climate change and decreased inorganic acid deposition. Here, we carried out a large scale multi-seasonal investigation in the Adirondacks, one of the most acid-impacted regions in the United States, to assess how acid stream producers respond to local and watershed influences and whether these influences can be used in acidification remediation. We explored the pathways of wetland control on aluminum chemistry and diatom taxonomic and functional composition. We demonstrate that streams with larger watershed wetlands have higher organic content, lower concentrations of acidic anions, and lower ratios of inorganic to organic monomeric aluminum, all beneficial for diatom biodiversity and guilds producing high biomass. Although brownification has been viewed as a form of pollution, our results indicate that it may be a stimulating force for biofilm producers with potentially positive consequences for higher trophic levels. Our research also reveals that the mechanism of watershed control of local stream diatom biodiversity through wetland export of organic matter is universal in running waters, operating not only in hard streams, as previously reported, but also in acid streams. Our findings that the negative impacts of acid deposition on Adirondack stream chemistry and biota can be mitigated by wetlands have important implications for biodiversity conservation and stream ecosystem management. Future acidification research should focus on the potential for wetlands to improve stream ecosystem health in acid-impacted regions and their direct use in stream restoration, for example, through

  19. Acidic deposition and its effects on forest productivity: a review of the present state of knowledge, research activities, and information needs

    SciTech Connect

    Pinkerton, J.E.

    1981-01-01

    The present state of knowledge with regard to acid deposition is reviewed. Sources include the literature and direct contact with persons responsible for carrying out all completed, ongoing, and planned research activities, national and international, related to acidic deposition and its effects, with emphasis on forest productivity. In addition, a list of information needs in seven areas was developed, these include: a characterization of forest soils to define their sensitivity to acidic deposition; effects on forest soil chemical and biological processes; development of improved dry deposition measurement methods; changes in precipitation composition due to forest canopies; more extensive monitoring of acidic deposition in industry owned forest lands; expansion of long-term greenhouse and controlled field experiments; and the relationship of acidic deposition and intensive forestry management practices. 85 references. (MDF)

  20. Atmospheric deposition and canopy exchange of anions and cations in two plantation forests under acid rain influence

    NASA Astrophysics Data System (ADS)

    Shen, Weijun; Ren, Huili; Darrel Jenerette, G.; Hui, Dafeng; Ren, Hai

    2013-01-01

    Acid deposition as a widely concerned environmental problem in China has been less studied in plantation forests compared to urban and secondary forests, albeit they constitute 1/3 of the total forested areas of the country. We measured the rainwater amount and chemistry outside and beneath the canopies of two widely distributed plantations (Acacia mangium and Dimocarpus longan) in the severe acid rain influenced Pearl River Delta region of southeastern China for two years. Our results showed that the frequency of acid rain was 96% on the basis of pH value <5.6. The volume-weighted mean (vwm) pH was 4.62 and higher in the dry (Oct.-Mar.) than in the wet (Apr.-Sep.) seasons. The major acidic anion was sulfate with vwm concentration of 140 μeq l-1 and annual deposition flux of 110.3 kg ha-1 yr-1. The major neutralizing cations were calcium (94.8 μeq l-1 and 28 kg ha-1 yr-1) and ammonium (41.2 μeq l-1 and 11.7 kg ha-1 yr-1). Over 95% of these major acidic anions and neutralizing cations were derived from anthropogenic and terrestrial sources as a result of industrial, agricultural and forestry activities. Plantation canopy had marked impacts on rainwater chemistry, with the measured anion and cation concentrations being significantly enriched in throughfall (TF) and stemflow (SF) rainwater by 1.4 (for NO) to 20-fold (for K+) compared to those in bulk precipitation (BP). Dry deposition generally contributed about 13-22% of the total deposition while canopy leaching mainly occurred for K+ (>88%) and NH (10-38%). The two tree species showed distinct impacts on rainfall redistribution and rainwater chemistry due to their differences in canopy architecture and leaf/bark texture, suggesting that species-specific effects should not be overlooked while assessing the acid deposition in forested areas.

  1. Correlation between energy deposition and molecular damage from Auger electrons: A case study of ultra-low energy (5–18 eV) electron interactions with DNA

    PubMed Central

    Rezaee, Mohammad; Hunting, Darel J.; Sanche, Léon

    2015-01-01

    Purpose The present study introduces a new method to establish a direct correlation between biologically related physical parameters (i.e., stopping and damaging cross sections, respectively) for an Auger-electron emitting radionuclide decaying within a target molecule (e.g., DNA), so as to evaluate the efficacy of the radionuclide at the molecular level. These parameters can be applied to the dosimetry of Auger electrons and the quantification of their biological effects, which are the main criteria to assess the therapeutic efficacy of Auger-electron emitting radionuclides. Methods Absorbed dose and stopping cross section for the Auger electrons of 5–18 eV emitted by 125I within DNA were determined by developing a nanodosimetric model. The molecular damages induced by these Auger electrons were investigated by measuring damaging cross section, including that for the formation of DNA single- and double-strand breaks. Nanoscale films of pure plasmid DNA were prepared via the freeze-drying technique and subsequently irradiated with low-energy electrons at various fluences. The damaging cross sections were determined by employing a molecular survival model to the measured exposure–response curves for induction of DNA strand breaks. Results For a single decay of 125I within DNA, the Auger electrons of 5–18 eV deposit the energies of 12.1 and 9.1 eV within a 4.2-nm3 volume of a hydrated or dry DNA, which results in the absorbed doses of 270 and 210 kGy, respectively. DNA bases have a major contribution to the deposited energies. Ten-electronvolt and high linear energy transfer 100-eV electrons have a similar cross section for the formation of DNA double-strand break, while 100-eV electrons are twice as efficient as 10 eV in the induction of single-strand break. Conclusions Ultra-low-energy electrons (<18 eV) substantially contribute to the absorbed dose and to the molecular damage from Auger-electron emitting radionuclides; hence, they should be considered in the

  2. Correlation between energy deposition and molecular damage from Auger electrons: A case study of ultra-low energy (5–18 eV) electron interactions with DNA

    SciTech Connect

    Rezaee, Mohammad Hunting, Darel J.; Sanche, Léon

    2014-07-15

    Purpose: The present study introduces a new method to establish a direct correlation between biologically related physical parameters (i.e., stopping and damaging cross sections, respectively) for an Auger-electron emitting radionuclide decaying within a target molecule (e.g., DNA), so as to evaluate the efficacy of the radionuclide at the molecular level. These parameters can be applied to the dosimetry of Auger electrons and the quantification of their biological effects, which are the main criteria to assess the therapeutic efficacy of Auger-electron emitting radionuclides. Methods: Absorbed dose and stopping cross section for the Auger electrons of 5–18 eV emitted by{sup 125}I within DNA were determined by developing a nanodosimetric model. The molecular damages induced by these Auger electrons were investigated by measuring damaging cross section, including that for the formation of DNA single- and double-strand breaks. Nanoscale films of pure plasmid DNA were prepared via the freeze-drying technique and subsequently irradiated with low-energy electrons at various fluences. The damaging cross sections were determined by employing a molecular survival model to the measured exposure–response curves for induction of DNA strand breaks. Results: For a single decay of{sup 125}I within DNA, the Auger electrons of 5–18 eV deposit the energies of 12.1 and 9.1 eV within a 4.2-nm{sup 3} volume of a hydrated or dry DNA, which results in the absorbed doses of 270 and 210 kGy, respectively. DNA bases have a major contribution to the deposited energies. Ten-electronvolt and high linear energy transfer 100-eV electrons have a similar cross section for the formation of DNA double-strand break, while 100-eV electrons are twice as efficient as 10 eV in the induction of single-strand break. Conclusions: Ultra-low-energy electrons (<18 eV) substantially contribute to the absorbed dose and to the molecular damage from Auger-electron emitting radionuclides; hence, they should

  3. A three-dimensional methodology for the assessment of neutron damage and nuclear energy deposition in graphite components of advanced gas-cooled reactors

    SciTech Connect

    Morgan, D.O.; Robinson, A.T.; Allen, D.A.; Picton, D.J.; Thornton, D.A.; Shaw, S.E.

    2011-07-01

    This paper describes the development of a three-dimensional methodology for the assessment of neutron damage and nuclear energy deposition (or nuclear heating) throughout the graphite cores of the UK's Advanced Gas-cooled Reactors. Advances in the development of the Monte Carlo radiation transport code MCBEND have enabled the efficient production of detailed fully three-dimensional models that utilise three-dimensional source distributions obtained from Core Follow data supplied by the reactor physics code PANTHER. The calculational approach can be simplified to reduce both the requisite number of intensive radiation transport calculations, as well as the quantity of data output. These simplifications have been qualified by comparison with explicit calculations and they have been shown not to introduce significant systematic uncertainties. Simple calculational approaches are described that allow users of the data to address the effects on neutron damage and nuclear energy deposition predictions of the feedback resulting from the mutual dependencies of graphite weight loss and nuclear energy deposition. (authors)

  4. Efficacy of 2,3-dimercapto-1-propanesulfonic acid (DMPS) and diphenyl diselenide on cadmium induced testicular damage in mice.

    PubMed

    Santos, Francielli W; Zeni, Gilson; Rocha, Joao B T; do Nascimento, Paulo C; Marques, Marieli S; Nogueira, Cristina W

    2005-12-01

    The deleterious effect of acute cadmium-intoxication in mice testes was evaluated. Animals received a single dose of CdCl2 (2.5 or 5 mg/kg, intraperitoneally) and a number of toxicological parameters in mice testes were examined, such as delta-aminolevulinic acid dehydratase (delta-ALA-D) activity, lipid peroxidation, hemoglobin and ascorbic acid contents. Furthermore, the parameters that indicate tissue damage such as plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were also determined. Thus, a possible protective effect of 2,3-dimercapto-1-propane-sulfonic acid (DMPS) and diphenyl diselenide (PhSe)2 were studied. The results demonstrated an inhibition of delta-ALA-D activity, a reduction of ascorbic acid and an increase of lipid peroxidation induced by cadmium, indicating testes damage. Furthermore, we observed an increase of plasma LDH, AST and ALT activities. DMPS (400 mol/kg) and (PhSe)2 (100 micromol/kg) partially protected from the inhibitory effect of 2.5 mg/kg CdCl2 on delta-ALA-D and from the increase of TBARS (thiobarbituric acid reactive species) levels. (PhSe)2 therapy was effective in ameliorate ascorbic acid content when the cadmium dose was 2.5 mg/kg. Treatment with DMPS and (PhSe)2, individually or combined, was inefficient in reducing cadmium-induced plasma LDH and ALT activity increase. The use of combined therapy (DMPS plus (PhSe)2) proved to be efficient in decreasing cadmium levels in testes and in ameliorating plasma AST activity from animals that received the highest dose of cadmium. PMID:16000234

  5. Failure of the inhibition of rat gastric mucosal 5-lipoxygenase by novel acetohydroxamic acids to prevent ethanol-induced damage.

    PubMed

    Boughton-Smith, N K; Whittle, B J

    1988-09-01

    1. The role of leukotriene B4 (LTB4) and LTC4 as mediators of gastric mucosal damage following ethanol challenge in vivo has been investigated using two selective 5-lipoxygenase inhibitors, BW A4C and BW A137C. 2. Oral administration of ethanol to rats in vivo, induced macroscopic damage to the gastric mucosa and markedly increased the formation of the 5-lipoxygenase products, LTB4 and LTC4, from the mucosa ex vivo. 3. Pretreatment with the acetohydroxamic acids BW A4C and BW A137C (5-50 mg kg-1 p.o.) dose-dependently reduced ethanol-stimulated LTB4 and LTC4 formation by the gastric mucosa, with an ID50 of approximately 5 mg kg-1 p.o. 4. A single oral dose of BW A4C (20 mg kg-1) induced near-maximal inhibition of mucosal LTB4 formation within 30 min, which was well maintained for 5 h, whereas BW A137C (20 mg kg-1 p.o.) induced maximal inhibition between 30 and 60 min after administration, which then diminished over the subsequent 5 h. 5. The mucosal formation of the cyclo-oxygenase product, 6-keto-prostaglandin F1 alpha, which was unaltered following ethanol challenge, was not inhibited by the acetohydroxamic acids. Likewise, the small increase in mucosal thromboxane B2 formation following challenge was not inhibited by BW A4C. 6. Neither BW A4C nor BW A137C, at doses that almost completely inhibited the mucosal synthesis of LTB4 or LTC4, reduced the macroscopic gastric mucosal damage induced by ethanol. 7. Pretreatment with the lipoxygenase inhibitor BW 755C (5-50 mg kg-1 p.o.) did reduce mucosal damage, but there was a dissociation between the degree of protection and the inhibition of leukotriene biosynthesis. 8. Oral administration of high doses of either BW A4C or BW A137C (300mgkg-1) did not induce macroscopic gastric damage over a 3 h period. 9. These findings suggest that the leukotrienes, LTB4 and LTC4 are not the primary mediators of ethanol-induced acute mucosal damage, but do not exclude their role in more chronic gastric damage and inflammation. PMID

  6. ACID DEPOSITION STRATEGIES, THE LIMB (LIMESTONE INJECTION/MULTISTAGE BURNERS) PROGRAM AND IMPLICATIONS FOR CONTROL TECHNOLOGY REQUIREMENTS

    EPA Science Inventory

    The paper summarizes the various acid deposition bills introduced in the U.S. Congress during the past 2 years and discusses emission sources. A rapidly emerging technology called Limestone Injection/Multistage Burners (LIMB), which has the potential for simultaneous SO2 and NOx ...

  7. Rainwater trifluoroacetic acid (TFA) in Guangzhou, South China: levels, wet deposition fluxes and source implication.

    PubMed

    Wang, Qiaoyun; Wang, Xinming; Ding, Xiang

    2014-01-15

    The origin of trifluoroacetic acid (TFA) occurring in hydrosphere has long been a controversial issue. Hydrochlorofluorocarbons and hydrofluorocarbons (HCFCs/HFCs) as replacements of chlorofluorocarbons (CFCs) are precursors of TFA in the atmosphere, their contribution to rainwater TFA is a concern as their ambient mixing ratios are continually growing. Here we present rainwater TFA monitored from April 2007 to March 2008 in urban Guangzhou, a central city in south China's highly industrialized and densely populated Pearl River Delta region. Rainwater TFA levels ranged 45.8-974 ng L(-1) with a median of 166 ng L(-1). TFA levels negatively correlated with rainfall amount, the yearly rainfall-weighted average for TFA was 152 ng L(-1). The annual TFA wet deposition flux was estimated to be 229 g km(-2) yr(-1), and the total wet deposition of TFA reached ~1.7 tyr(-1) in Guangzhou. The Two-Box model was applied to estimate attributions of HCFCs/HFCs and fluoropolymers to rainwater TFA assuming TFA generated was proportional to gross domestic product (GDP), gross industrial product (GIP) or number of private cars. The results revealed that the degradation of HCFCs/HFCs and fluoropolymers could explain 131.5-152.4 ng L(-1) rainwater TFA, quite near the observed rainfall-weighted annual mean of 152 ng L(-1), suggesting rainwater TFA in Guangzhou was predominantly originated from these anthropogenic precursors. HCFCs/HFCs accounted for 83.3-96.5% of rainwater TFA observed, while fluoropolymers' contributions were minor (~5%). HFC-134a alone could explain 55.9-90.0% of rainwater TFA, and its contribution would be greatly enhanced with its wide use in mobile air conditioning systems and rapid increase in ambient mixing ratios. PMID:24035981

  8. Does rosmarinic acid treatment have protective role against sepsis-induced oxidative damage in Wistar Albino rats?

    PubMed

    Bacanlı, M; Aydın, S; Taner, G; Göktaş, H G; Şahin, T; Başaran, A A; Başaran, N

    2016-08-01

    Reactive oxygen species are believed to be involved in the development of sepsis. Plant-derived phenolic compounds are thought to be possible therapeutic agents against sepsis because of their antioxidant properties. Rosmarinic acid (RA) is a phenolic compound commonly found in various plants, which has many biological activities including antioxidant activity. The aim of this study was to investigate the effects of RA on sepsis-induced DNA damage in the lymphocytes and liver and kidney cells of Wistar albino rats by alkaline comet assay with and without formamidopyrimidine DNA glycosylase protein. The oxidative stress parameters such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and total glutathione (GSH) and malondialdehyde (MDA) levels in the liver and kidney tissues and an inflammatory cytokine, tumor necrosis factor α (TNF-α) level in plasma were also evaluated. It is found that DNA damage in the lymphocytes, livers, and kidneys of the RA-treated rats was significantly lower than that in the sepsis-induced rats. RA treatment also decreased the MDA levels and increased the GSH levels and SOD and GSH-Px activities in the livers and kidneys of the sepsis-induced rats. Plasma TNF-α level was found to be decreased in the RA-treated rats. It seems that RA might have a role in the attenuation of sepsis-induced oxidative damage not only by decreasing the DNA damage but also by increasing the antioxidant status and DNA repair capacity of the animals. PMID:26429925

  9. DEPOSITION TANK CORROSION TESTING FOR ENHANCED CHEMICAL CLEANING POST OXALIC ACID DESTRUCTION

    SciTech Connect

    Mickalonis, J.

    2011-08-29

    An Enhanced Chemical Cleaning (ECC) process is being developed to aid in the high level waste tank closure at the Savannah River Site. The ECC process uses an advanced oxidation process (AOP) to destroy the oxalic acid that is used to remove residual sludge from a waste tank prior to closure. The AOP process treats the dissolved sludge with ozone to decompose the oxalic acid through reactions with hydroxyl radicals. The effluent from this oxalic acid decomposition is to be sent to a Type III waste tank and may be corrosive to these tanks. As part of the hazardous simulant testing that was conducted at the ECC vendor location, corrosion testing was conducted to determine the general corrosion rate for the deposition tank and to assess the susceptibility to localized corrosion, especially pitting. Both of these factors impact the calculation of hydrogen gas generation and the structural integrity of the tanks, which are considered safety class functions. The testing consisted of immersion and electrochemical testing of A537 carbon steel, the material of construction of Type III tanks, and 304L stainless steel, the material of construction for transfer piping. Tests were conducted in solutions removed from the destruction loop of the prototype ECC set up. Hazardous simulants, which were manufactured at SRNL, were used as representative sludges for F-area and H-area waste tanks. Oxalic acid concentrations of 1 and 2.5% were used to dissolve the sludge as a feed to the ECC process. Test solutions included the uninhibited effluent, as well as the effluent treated for corrosion control. The corrosion control options included mixing with an inhibited supernate and the addition of hydroxide. Evaporation of the uninhibited effluent was also tested since it may have a positive impact on reducing corrosion. All corrosion testing was conducted at 50 C. The uninhibited effluent was found to increase the corrosion rate by an order of magnitude from less than 1 mil per year (mpy

  10. Defending the leaf surface: intra- and inter-specific differences in silicon deposition in grasses in response to damage and silicon supply

    PubMed Central

    Hartley, Sue E.; Fitt, Rob N.; McLarnon, Emma L.; Wade, Ruth N.

    2015-01-01

    Understanding interactions between grasses and their herbivores is central to the conservation of species-rich grasslands and the protection of our most important crops against pests. Grasses employ a range of defenses against their natural enemies; silicon-based defenses have been shown to be one of the most effective. Silicon (Si) is laid down on the leaf surface as spines and other sharp bodies, known as phytoliths, making grasses abrasive and their foliage indigestible to herbivores. Previous studies on Si defenses found that closely related species may have similar levels of Si in the leaves but differ markedly in abrasiveness. Here we show how the number, shape and distribution of Si-rich phytoliths and spines differ within and between different grass species and demonstrate that species also differ in their ability to change the deposition and distribution of these defenses in response to damage or increases in Si supply. Specifically, we tested the response of two genotypes of Festuca arundinacea known to differ in their surface texture and three different grass species (F. ovina, F. rubra, and Deschampsia cespitosa) differing in their abrasiveness to combined manipulation of leaf damage and Si supply. F. arundinacea plants with a harsh leaf surface had higher Si content and more spines on their leaf surface than soft varieties. F. ovina and D. cespitosa plants increased their leaf Si concentration and produced an increase in the number of leaf spines and phytoliths on the leaf surface in response to Si addition. F rubra also increased leaf Si content in response to treatments, particularly in damaged leaves, but did not deposit this in the form of spines or increased densities of phytoliths. We discuss how the form in which grasses deposit Si may affect their anti-herbivore characteristics and consider the ecological and agricultural implications of the differences in allocation to Si-based defenses between grass species. PMID:25717331

  11. Variation of Atmospheric Deposition of Acid Species and Yellow Sand Particles From 1987 to 1999 Through Modeling Studies and Observations

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Uno, I.; Zhang, M.; Akimoto, H.

    2002-05-01

    Acid deposition is of serious environmental concern in East Asia. Wet and dry deposition monitoring datasets have been collected for long enough to understand the deposition distribution and its variation in time and space in this region Field observations indicate that acid precipitation often occurs in the southern part of China, even though emissions of the precursors are stronger in the north, where such high levels of strong acids in precipitation have not been widely. The acidity of rainwater is heavily influenced and modified by natural soil dust from desert and semi-arid areas. This soil aerosol, or _gKOSA", is lifted from Asian deserts and the Loess plateau, and then carried by the prevailing wind over East Asia. A comprehensive Air Quality Prediction Modeling System (AQPMS) is used to perform year-long, quantitative simulation of rainwater pH in East Asia for 1987 and 1999, respectively with emissions of Akimoto et al.(1987) and Street et al.(2000), to discuss the variation of deposition of acid species and yellow sand particles due to the emission change in the past dozen years. Monitoring data at 17 sites of EANET (the Acid Deposition Monitoring Network in East Asia) in addition to the field observation data of SEPA(State Environmental Protection Agency) of China are used to evaluate the model, and a reasonable agreement is obtained. Emission in Sichuan province has decreased and emission in central China including Hubei province and Hunan province has increased. Model simulation shows the change of emission pattern caused the serious acid-rain-hit area moving southeastward as observed. In the west part of Sichuan province, the pH value increased, this is partly due to the success of countermeasures against acid rain in China since 1996, which reduce the emission in Sichuan area much more than expected. The variations of annual distribution of rain pH, sulfate, nitrite and yellow sand particles deposition are also discussed in detail, so do the

  12. Quantifying uncertainties in sulphur and nitrogen deposition to wales, uk using the hull acid rain model (harm) within the generalised likelihood uncertainty estimation (glue) framework

    NASA Astrophysics Data System (ADS)

    Page, T.; Whyatt, D.; Beven, K.; Metcalfe, S.; Nicholson, J.

    2003-04-01

    The Hull Acid Rain Model (HARM) is a receptor orientated Lagrangian trajectory model used to represent the processes of emission, transformation and deposition of acidifying species. HARM employs a simplified representation of meteorological conditions. It has a coupled chemical scheme and includes a parameterisation of orographic enhancement which is believed to make a significant contribution to wet deposition in upland UK. An uncertainty analysis of the model using the Generalised Likelihood Uncertainty Estimation methodology (GLUE) is presented, as constrained on multiple observations at 25 sites across Wales, UK. The quantified uncertainty is used to investigate the effect of predictive uncertainty on critical load exceedance. The GLUE analysis comprised 100,000 model realisations from Monte Carlo sampling of pre-specified parameter ranges, which were evaluated on the basis of how well simulated fluxes matched those measured at all observation sites. Only 2101 simulations were deemed to produce adequate representations of the observed fluxes and were used to create weighted prediction bounds for each site. Overall, the uncertainty prediction bounds spanned the observed data satisfactorily for most sites, but there was a tendency for high rainfall sites to be overestimated and sites close to major source areas to be underestimated. For wet-deposited oxidised-N there was a systematic overestimation at the majority of sites. The overestimation of wet-deposited oxidised-N for Wales is in contrast to other regions of the UK, where it is underestimated. The predictive capability of HARM was tested with a ‘hindcast’ to 44 Welsh observation sites for 1984 by using the 2101 acceptable parameterizations for 1995 with a 1984 emissions inventory. The spatial pattern of model predictions was consistent between 1984 and 1995 leading to the conclusion that either: model structural change is required to improve HARMs ability to represent the spatial deposition pattern or

  13. A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus

    NASA Astrophysics Data System (ADS)

    Vet, Robert; Artz, Richard S.; Carou, Silvina; Shaw, Mike; Ro, Chul-Un; Aas, Wenche; Baker, Alex; Bowersox, Van C.; Dentener, Frank; Galy-Lacaux, Corinne; Hou, Amy; Pienaar, Jacobus J.; Gillett, Robert; Forti, M. Cristina; Gromov, Sergey; Hara, Hiroshi; Khodzher, Tamara; Mahowald, Natalie M.; Nickovic, Slobodan; Rao, P. S. P.; Reid, Neville W.

    2014-08-01

    A global assessment of precipitation chemistry and deposition has been carried out under the direction of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Scientific Advisory Group for Precipitation Chemistry (SAG-PC). The assessment addressed three questions: (1) what do measurements and model estimates of precipitation chemistry and wet, dry and total deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity, and phosphorus show globally and regionally? (2) has the wet deposition of major ions changed since 2000 (and, where information and data are available, since 1990) and (3) what are the major gaps and uncertainties in our knowledge? To that end, regionally-representative measurements for two 3-year-averaging periods, 2000-2002 and 2005-2007, were compiled worldwide. Data from the 2000-2002 averaging period were combined with 2001 ensemble-mean modeling results from 21 global chemical transport models produced in Phase 1 of the Coordinated Model Studies Activities of the Task Force on Hemispheric Transport of Air Pollution (TF HTAP). The measurement data and modeling results were used to generate global and regional maps of major ion concentrations in precipitation and deposition. A major product of the assessment is a database of quality assured ion concentration and wet deposition data gathered from regional and national monitoring networks. The database is available for download from the World Data Centre for Precipitation Chemistry (http://wdcpc.org/)

  14. Nicotinic acid supplementation in diet favored intramuscular fat deposition and lipid metabolism in finishing steers.

    PubMed

    Yang, Zhu-Qing; Bao, Lin-Bin; Zhao, Xiang-Hui; Wang, Can-Yu; Zhou, Shan; Wen, Lu-Hua; Fu, Chuan-Bian; Gong, Jian-Ming; Qu, Ming-Ren

    2016-06-01

    Nicotinic acid (NA) acting as the precursor of NAD(+)/NADH and NADP(+)/NADPH, participates in many biochemical processes, e.g. lipid metabolism. The main purpose of this study was to investigate the effects of dietary NA on carcass traits, meat quality, blood metabolites, and fat deposition in Chinese crossbred finishing steers. Sixteen steers with the similar body weight and at the age of 24 months were randomly allocated into control group (feeding basal diet) and NA group (feeding basal diet + 1000 mg/kg NA). All experimental cattle were fed a 90% concentrate diet and 10% forage straw in a 120-day feeding experiment. The results showed that supplemental NA in diet increased longissimus area, intramuscular fat content (17.14% vs. 9.03%), marbling score (8.08 vs. 4.30), redness (a*), and chroma (C*) values of LD muscle, but reduced carcass fat content (not including imtramuscular fat), pH24 h and moisture content of LD muscle, along with no effect on backfat thickness. Besides, NA supplementation increased serum HDL-C concentration, but decreased the serum levels of LDL-C, triglyceride, non-esterified fatty acid, total cholesterol, and glycated serum protein. In addition, NA supplementation increased G6PDH and ICDH activities of LD muscle. These results suggested that NA supplementation in diet improves the carcass characteristics and beef quality, and regulates the compositions of serum metabolites. Based on the above results, NA should be used as the feed additive in cattle industry. PMID:27048556

  15. Nitric acid dry deposition to conifer forests: Niwot Ridge spruce-fir-pine study

    USGS Publications Warehouse

    Sievering, H.; Kelly, T.; McConville, G.; Seibold, C.; Turnipseed, A.

    2001-01-01

    The dry deposition velocity of nitric acid, Vd(HNO3), over a 12-m (mean height) spruce-fir forest at Niwot Ridge, Colorado was estimated during 13 daytime periods using the flux-gradient approach. Turbulence intensity at this site is high (mean u* of 0.65ms-1 with u of 2.9ms-1) and contributed to the large observed Vd(HNO3). The overriding contributor is identified to be the small aerodynamic needle width of the conifer trees. Two cases had inflated Vd(HNO3) due to height-differentiated nitric acid loss to soil-derived particle surfaces. Not considering these cases, the mean Vd(HNO3) was 7.6cms-1. The mean laminar boundary layer resistance (Rb) was found to be 7.8sm-1 (of similar magnitude to that of the aerodynamic resistance, 8.5sm-1). The data-determined Rb is bracketed by two theoretical estimates of the mean Rb, 5.9 and 8.6sm-1, that include consideration of the small canopy length scale (aerodynamic needle width), 1mm or less, at this conifer forest. However, the poor correlation of data-determined Rb values with both sets of theoretical estimates indicates that measurement error needs to be reduced and/or improved formulations of theoretical Rb values are in order. The large observed Vd(HNO3) at this conifer forest site is attributed to high turbulence intensity, and, especially, to small aerodynamic needle width. Copyright ?? 2001 Elsevier Science Ltd.

  16. Naringin ameliorates acetic acid induced colitis through modulation of endogenous oxido-nitrosative balance and DNA damage in rats

    PubMed Central

    Kumar, Venkatashivam Shiva; Rajmane, Anuchandra Ramchandra; Adil, Mohammad; Kandhare, Amit Dattatraya; Ghosh, Pinaki; Bodhankar, Subhash Laxman

    2014-01-01

    The aim of this study was to evaluate the effect of naringin on experimentally induced inflammatory bowel disease in rats. Naringin (20, 40 and 80 mg/kg) was given orally for 7 days to Wistar rats before induction of colitis by intrarectal instillation of 2 mL of 4% (v/v) acetic acid solution. The degree of colonic mucosal damage was analyzed by examining mucosal damage, ulcer area, ulcer index and stool consistency. Intrarectal administration of 4% acetic acid resulted in significant modulation of serum alkaline phosphatase, lactate dehydrogenase, superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA) and myeloperoxidase (MPO) content along with colonic nitric oxide (NO), xanthine oxidase (XO) level and protein carbonyl content in the colonic tissue as well as in blood. Naringin (40 and 80 mg/kg) exerted a dose dependent (P < 0.05) ameliorative effect, as it significantly increased hematological parameter as well as colonic SOD and GSH. There was a significant (P < 0.05) and dose dependant inhibition of macroscopical score, ulcer area along with colonic MDA, MPO activity by the 7 days of pretreatment of naringin (40 and 80 mg/kg). Biochemical studies revealed a significant (P < 0.05) dose dependant inhibition in serum alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) levels by pretreatment of naringin. Increased levels of colonic NO, XO, protein carbonyl content and DNA damage were also significantly decreased by naringin pretreatment. The findings of the present investigation propose that naringin has an anti-inflammatory, anti-oxidant and anti-apoptotic potential effect at colorectal sites as it modulates the production and expression of oxidative mediators such as MDA, MPO, NO and XO, thus reducing DNA damage. PMID:24683411

  17. Effects of acidic deposition on the erosion of carbonate stone - experimental results from the U.S. National Acid Precipitation Assessment Program (NAPAP)

    USGS Publications Warehouse

    Baedecker, P.A.; Reddy, M.M.; Reimann, K.J.; Sciammarella, C.A.

    1992-01-01

    One of the goals of NAPAP-sponsored research on the effects of acidic deposition on carbonate stone has been to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulfur dioxide and nitrogen oxides on stone erosion. Test briquettes and slabs of freshly quarried Indiana limestone and Vermont marble have been exposed to ambient environmental conditions in a long-term exposure program. Physical measurements of the recession of test stones exposed to ambient conditions at an angle of 30?? to horizontal at the five NAPAP materials exposure sites range from ~15 to ~30?? ??m yr-1 for marble, and from ~25 to ~45 ??m yr -1 for limestone, and are approximately double the recession estimates based on the observed calcium content of run-off solutions from test slabs. The difference between the physical and chemical recession measurements is attributed to the loss of mineral grains from the stone surfaces that are not measured in the run-off experiments. The erosion due to grain loss does not appear to be influenced by rainfall acidity, however, preliminary evidence suggests that grain loss may be influenced by dry deposition of sulfur dioxide between rainfall events. Chemical analyses of the run-off solutions and associated rainfall blanks suggest that ~30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulfur dioxide and nitric acid between rain events. The remaining ~70% of erosion by dissolution is accounted for by the solubility of carbonate stone in rain that is in equilibrium with atmospheric carbon dioxide ('clean rain'). These results are for marble and limestone slabs exposed at an angle of 30?? from horizontal. The relative contribution of sulfur dioxide to chemical erosion is significantly enhanced for stone slabs having an inclination of 60?? or 85??. The dry deposition of alkaline particulate material has a mitigating effect at the two urban field exposure sites at Washington, DC

  18. The allelopathic effects of invasive plant Solidago canadensis on seed germination and growth of Lactuca sativa enhanced by different types of acid deposition.

    PubMed

    Wang, Congyan; Xiao, Hongguang; Zhao, Lulu; Liu, Jun; Wang, Lei; Zhang, Fei; Shi, Yanchun; Du, Daolin

    2016-04-01

    Invasive species can exhibit allelopathic effects on native species. Meanwhile, the types of acid deposition are gradually changing. Thus, the allelopathic effects of invasive species on seed germination and growth of native species may be altered or even enhanced under conditions with diversified acid deposition. This study aims to assess the allelopathic effects (using leaves extracts) of invasive plant Solidago canadensis on seed germination and growth of native species Lactuca sativa treated with five types of acid deposition with different SO4(2-) to NO3(-) ratios (1:0, sulfuric acid; 5:1, sulfuric-rich acid; 1:1, mixed acid; 1:5, nitric-rich acid; 0:1, nitric acid). Solidago canadensis leaf extracts exhibited significantly allelopathic effects on germination index, vigor index, and germination rate index of L. sativa. High concentration of S. canadensis leaf extracts also similarly exhibited significantly allelopathic effects on root length of L. sativa. This may be due to that S. canadensis could release allelochemicals and then trigger allelopathic effects on seed germination and growth of L. sativa. Acid deposition exhibited significantly negative effects on seedling biomass, root length, seedling height, germination index, vigor index, and germination rate index of L. sativa. This may be ascribed to the decreased soil pH values mediated by acid deposition which could produce toxic effects on seedling growth. Sulfuric acid deposition triggered more toxic effects on seedling biomass and vigor index of L. sativa than nitric acid deposition. This may be attributing to the difference in exchange capacity with hydroxyl groups (OH(-)) between SO4(2-) and NO3(-) as well as the fertilizing effects mediated by nitric deposition. All types of acid deposition significantly enhanced the allelopathic effects of S. canadensis on root length, germination index, vigor index, and germination rate index of L. sativa. This may be due to the negatively synergistic effects of

  19. Extra virgin olive oil modulates brain docosahexaenoic acid level and oxidative damage caused by 2,4-Dichlorophenoxyacetic acid in rats.

    PubMed

    Amel, Nakbi; Wafa, Tayeb; Samia, Dabbou; Yousra, Belaid; Issam, Chargui; Cheraif, Imed; Attia, Nebil; Mohamed, Hammami

    2016-03-01

    Oxidative stress is an important pathomechanism of neurological disorders such as Alzheimer disease and Parkinson disease, cardiovascular disorders and many others. This study sought to verify whether extra-virgin olive oil (EVOO), lipophilic fraction (OOLF) and hydrophilic fraction (OOHF) exerted a brain protective effect against the oxidative stress caused by 2,4-dichlorophenoxyacetic acid (2,4-D) pesticide at a dose of 5 mg/kg body weight. 2,4-D, EVOO and its fractions were administered to rats by gavages for four consecutive weeks. Oxidative stress was assessed by measuring brain lipid peroxide level, acetylcholinesterase (AChE), antioxidant enzyme activities and fatty acid composition. 2,4-D induced a decrease in both plasma and brain acetylcholinesterase activity and a rise in Brain TBARS (Thiobarbituric acid reactive substances) level and antioxidant enzyme activities compared with the control group. These changes were partly reversed by either EVOO or its fractions oral administration to 2,4-D treated rats. EVOO enhanced a neuroprotective effect evaluated by the restoration of brain fatty acid composition especially the level of docosahexaenoic acid (DHA). Our results indicate that EVOO exerts a neuroprotective activity against oxidative damage in brain induced by 2,4-D, which could be attributed to its antioxidative property. PMID:27570270

  20. Acid deposition in Maryland. Summary of research and monitoring results compiled through 1991 and a discussion of the 1990 Clean Air Act Amendments. Report for 1991-1992

    SciTech Connect

    Price, R.; Mountain, D.

    1992-10-01

    This is the sixth annual report submitted under Maryland legislative requirements. The report focuses on more than a decade of acid deposition research conducted in Maryland. In addition, the report discusses Title IV - Acid Deposition Control of the 1990 Clean Air Act Amendments (CAAA) and its potential impacts on Maryland.

  1. The effects of acid deposition on sulfate reduction and methane production in peatlands

    NASA Technical Reports Server (NTRS)

    Murray, Georgia L.; Hines, Mark E.; Bayley, Suzanne E.

    1992-01-01

    Peatlands, as fens and bods, make up a large percentage of northern latitude terrestrial environments. They are organic rich and support an active community of anaerobic bacteria, such as methanogenic and sulfate-reducing bacteria. The end products of these microbial activities, methane and hydrogen sulfide, are important components in the global biogeochemical cycles of carbon and sulfur. Since these two bacterial groups compete for nutritional substrates, increases in sulfate deposition due to acid rain potentially can disrupt the balance between these processes leading to a decrease in methane production and emission. This is significant because methane is a potent greenhouse gas that effects the global heat balance. A section of Mire 239 in the Experimental Lakes Area, in Northwestern Ontario, was artificially acidified and rates of sulfate reduction and methane production were measured with depth. Preliminary results suggested that methane production was not affected immediately after acidification. However, concentrations of dissolved methane decreased and dissolved sulfide increased greatly after acidification and both took several days to recover. The exact mechanism for the decrease in methane was not determined. Analyses are under way which will be used to determine rates of sulfate reduction. These results will be available by Spring and will be discussed.

  2. Aqueous solution deposition kinetics of iron oxyhydroxide on sulfonic acid terminated self-assembled monolayers

    SciTech Connect

    Rieke, P.C.; Marsh, B.D.; Wood, L.L.; Tarasevich, B.J.; Liu, J.; Song, L.; Fryxell, G.E. )

    1995-01-01

    The deposition kinetics of iron oxyhydroxide on sulfonic acid terminated self-assembled monolayers were studied. The thin films of FeOOH were formed on the substrates by thermal hydrolysis of millimolar aqueous solutions of Fe(NO[sub 3])[sub 3] at a pH of approximately 2.0. The thickness of the films was measured ellipsometrically at various times. Both Fe(NO[sub 3])[sub 3] and HNO[sub 3] concentrations were independently varied to provide varying degrees of solution supersaturation. Depending on these concentrations, an induction time was observed before film growth commenced. The correlation between supersaturation and induction time was modeled using classical nucleation theory. Very good agreement was observed regardless of whether supersaturation was varied via the concentration of Fe(NO[sub 3])[sub 3] or HNO[sub 3]. From these results an interfacial free energy for nucleation of 148 mJ/m[sup 2] was calculated. The critical nucleus species was identified as a tetrameric iron species by considering the order of nucleation. 49 refs., 11 figs., 1 tab.

  3. A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus

    NASA Astrophysics Data System (ADS)

    Vet, Robert; Artz, Richard S.; Carou, Silvina

    2014-08-01

    Investigating and assessing the chemical composition of precipitation and atmospheric deposition is essential to understanding how atmospheric pollutants contribute to contemporary environmental concerns including ecosystem acidification and eutrophication, loss of biodiversity, air pollution and global climate change. Evidence of the link between atmospheric deposition and these environmental issues is well established. The state of scientific understanding of this link is that present levels of atmospheric deposition of sulfur and nitrogen adversely affect terrestrial and aquatic ecosystems, putting forest sustainability and aquatic biodiversity at risk. Nitrogen and phosphorus loadings are linked to impacts on the diversity of terrestrial and aquatic vegetation through biological cycling, and atmospheric deposition plays a major role in the emission-transport-conversion-loss cycle of chemicals in the atmosphere as well as the formation of particulate matter and ozone in the troposphere. Evidence also shows that atmospheric constituents are changing the earth's climate through direct and indirect atmospheric processes. This Special Issue, comprising a single article titled "A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus", presents a recent comprehensive review of precipitation chemistry and atmospheric deposition at global and regional scales. The information in the Special Issue, including all supporting data sets and maps, is anticipated to be of great value not only to the atmospheric deposition community but also to other science communities including those that study ecosystem impacts, human health effects, nutrient processing, climate change, global and hemispheric modeling and biogeochemical cycling. Understanding and quantifying pollutant loss from the atmosphere is, and will remain, an important component of each of these scientific fields as they

  4. Investigations on the SR method growth, etching, birefringence, laser damage threshold and dielectric characterization of sodium acid phthalate single crystals

    NASA Astrophysics Data System (ADS)

    Senthil, A.; Ramasamy, P.; Verma, Sunil

    2011-03-01

    Optically good quality semi-organic single crystal of sodium acid phthalate (NaAP) was successfully grown by Sankaranarayanan-Ramasamy (SR) method. Transparent, colourless <0 0 1> oriented unidirectional bulk single crystals of diameters 10 and 20 mm and length maximum up to 75 mm were grown by the SR method. The grown crystals were subjected to various characterization studies such as etching, birefringence, laser damage threshold, UV-vis spectrum and dielectric measurement. The value of birefringence and quality were ascertained by birefringence studies.

  5. Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York

    USGS Publications Warehouse

    Sullivan, Timothy J.; Lawrence, Gregory B.; Bailey, Scott W.; McDonnell, Todd C.; Beier, Colin M.; Weathers, K.C.; McPherson, G.T.; Bishop, Daniel A.

    2013-01-01

    We documented the effects of acidic atmospheric deposition and soil acidification on the canopy health, basal area increment, and regeneration of sugar maple (SM) trees across the Adirondack region of New York State, in the northeastern United States, where SM are plentiful but not well studied and where widespread depletion of soil calcium (Ca) has been documented. Sugar maple is a dominant canopy species in the Adirondack Mountain ecoregion, and it has a high demand for Ca. Trees in this region growing on soils with poor acid–base chemistry (low exchangeable Ca and % base saturation [BS]) that receive relatively high levels of atmospheric sulfur and nitrogen deposition exhibited a near absence of SM seedling regeneration and lower crown vigor compared with study plots with relatively high exchangeable Ca and BS and lower levels of acidic deposition. Basal area increment averaged over the 20th century was correlated (p < 0.1) with acid–base chemistry of the Oa, A, and upper B soil horizons. A lack of Adirondack SM regeneration, reduced canopy condition, and possibly decreased basal area growth over recent decades are associated with low concentrations of nutrient base cations in this region that has undergone soil Ca depletion from acidic deposition.

  6. Effects of dietary combination of n-3 and n-9 fatty acids on the deposition of linoleic and arachidonic acid in broiler chicken meats.

    PubMed

    Shin, D; Choi, S H; Go, G; Park, J H; Narciso-Gaytán, C; Morgan, C A; Smith, S B; Sánchez-Plata, M X; Ruiz-Feria, C A

    2012-04-01

    To minimize the amount of n-6 fatty acids in broiler chicken meat, 120 Cobb × Ross male broilers were divided into 6 different groups and fed a basal corn-soybean meal diet containing 5% fat from 5 different lipid sources: 1) a commercial mix of animal and vegetable oil, 2) soybean oil and olive oil (2.5% each), 3) flaxseed oil and olive oil (2.5% each), 4) flaxseed oil, eicosapentaenoic acid (C20:5; EPA; n-3), and olive oil (2.45, 0.05, and 2.5% respectively; FEO), 5) flaxseed oil, docosahexaenoic acid (C22:6; DHA; n-3), and olive oil (2.45, 0.05, and 2.5% respectively; FDO), and 6) fish oil and olive oil (2.5% each; FHO). At 6 and 9 wk, one bird per pen (4 pens per treatment) was processed, and liver, breast, and thigh samples were collected and used for fatty acid profiles or Δ6- and Δ9-desaturase mRNA gene expression levels. The deposition of linoleic acid (C18:2; n-6) or arachidonic acid (C20:4; n-6) was decreased in breast and thigh muscles of chickens fed n-3 fatty acids for 9 wk compared with chickens fed animal and vegetable oil and soybean oil and olive oil diets (P < 0.05). The addition of EPA to the diet (FEO; P > 0.05) did not reduce the deposition of linoleic acid and arachidonic acid as much as DHA (FDO; P < 0.05), and it suppressed the expression of Δ6- and Δ9-desaturase. When EPA and DHA were blended (FHO) and supplied to broiler chickens for 9 wk, EPA and DHA combination effects were observed on the deposition of LA and arachidonic acid in breast and thigh muscles. Thereby, the addition of a mixed EPA and DHA to a broiler chicken diet may be recommendable to reduce arachidonic acid accumulation in both broiler chicken breast and thigh meats, providing a functional broiler chicken meat to consumers. PMID:22399741

  7. Graphene oxide induces plasma membrane damage, reactive oxygen species accumulation and fatty acid profiles change in Pichia pastoris.

    PubMed

    Zhang, Meng; Yu, Qilin; Liang, Chen; Liu, Zhe; Zhang, Biao; Li, Mingchun

    2016-10-01

    During the past couple of years, graphene nanomaterials were extremely popular among the scientists due to the promising properties in many aspects. Before the materials being well applied, we should first focus on their biosafety and toxicity. In this study, we investigated the toxicity of synthesized graphene oxide (GO) against the model industrial organism Pichia pastoris. We found that the synthesized GO showed dose-dependent toxicity to P. pastoris, through cell membrane damage and intracellular reactive oxygen species (ROS) accumulation. In response to these cell stresses, cells had normal unsaturated fatty acid (UFA) levels but increased contents of polyunsaturated fatty acid (PUFA) with up-regulation of UFA synthesis-related genes on the transcriptional level, which made it overcome the stress under GO attack. Two UFA defective strains (spt23Δ and fad12Δ) were used to demonstrate the results above. Hence, this study suggested a close connection between PUFAs and cell survival against GO. PMID:27376352

  8. Bile acid receptor TGR5, NADPH Oxidase NOX5-S and CREB Mediate Bile Acid-Induced DNA Damage In Barrett’s Esophageal Adenocarcinoma Cells

    PubMed Central

    Li, Dan; Cao, Weibiao

    2016-01-01

    The mechanisms whereby bile acid reflux may accelerate the progression from Barrett’s esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. In this study we found that bile acid taurodeoxycholic acid (TDCA) significantly increased the tail moment (TM) and histone H2AX phosphorylation in FLO-1 EA cells, an increase which was significantly decreased by knockdown of TGR5. Overexpression of TGR5 significantly increased TDCA-induced TM increase and H2AX phosphorylation. In addition, NADPH oxidase inhibitor diphenylene iodonium significantly inhibited the TDCA-induced increase in TM and H2AX phosphorylation. TDCA-induced increase in TM and H2AX phosphorylation was significantly decreased by knockdown of NOX5-S and overexpression of NOX5-S significantly increased TDCA-induced increase in the tail moment and H2AX phosphorylation. Furthermore, TDCA significantly increased cAMP response element binding protein (CREB) phosphorylation in FLO-1 cells. Knockdown of CREB significantly decreased TDCA-induced increase in NOX5-S mRNA and the tail moment. Conversely, overexpression of CREB significantly increased TDCA-induced TM increase. We conclude that TDCA-induced DNA damage may depend on the activation of TGR5, CREB and NOX5-S. It is possible that in Barrett’s patients bile acids may activate NOX5-S and increase reactive oxygen species (ROS) production via activation of TGR5 and CREB. NOX5-S-derived ROS may cause DNA damage, thereby contributing to the progression from BE to EA. PMID:27511066

  9. Bile acid receptor TGR5, NADPH Oxidase NOX5-S and CREB Mediate Bile Acid-Induced DNA Damage In Barrett's Esophageal Adenocarcinoma Cells.

    PubMed

    Li, Dan; Cao, Weibiao

    2016-01-01

    The mechanisms whereby bile acid reflux may accelerate the progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. In this study we found that bile acid taurodeoxycholic acid (TDCA) significantly increased the tail moment (TM) and histone H2AX phosphorylation in FLO-1 EA cells, an increase which was significantly decreased by knockdown of TGR5. Overexpression of TGR5 significantly increased TDCA-induced TM increase and H2AX phosphorylation. In addition, NADPH oxidase inhibitor diphenylene iodonium significantly inhibited the TDCA-induced increase in TM and H2AX phosphorylation. TDCA-induced increase in TM and H2AX phosphorylation was significantly decreased by knockdown of NOX5-S and overexpression of NOX5-S significantly increased TDCA-induced increase in the tail moment and H2AX phosphorylation. Furthermore, TDCA significantly increased cAMP response element binding protein (CREB) phosphorylation in FLO-1 cells. Knockdown of CREB significantly decreased TDCA-induced increase in NOX5-S mRNA and the tail moment. Conversely, overexpression of CREB significantly increased TDCA-induced TM increase. We conclude that TDCA-induced DNA damage may depend on the activation of TGR5, CREB and NOX5-S. It is possible that in Barrett's patients bile acids may activate NOX5-S and increase reactive oxygen species (ROS) production via activation of TGR5 and CREB. NOX5-S-derived ROS may cause DNA damage, thereby contributing to the progression from BE to EA. PMID:27511066

  10. Laboratory study of acid stimulation of drilling-mud-damaged geothermal-reservoir materials. Final report

    SciTech Connect

    Not Available

    1983-05-01

    Presented here are the results of laboratory testing performed to provide site specific information in support of geothermal reservoir acidizing programs. The testing program included laboratory tests performed to determine the effectiveness of acid treatments in restoring permeability of geologic materials infiltrated with hydrothermally altered sepiolite drilling mud. Additionally, autoclave tests were performed to determine the degree of hydrothermal alteration and effects of acid digestion on drilling muds and drill cuttings from two KGRA's. Four laboratory scale permeability/acidizing tests were conducted on specimens prepared from drill cuttings taken from two geothermal formations. Two tests were performed on material from the East Mesa KGRA Well No. 78-30, from a depth of approximately 5500 feet, and two tests were performed on material from the Roosevelt KGRA Well No. 52-21, from depths of approximately 7000 to 7500 feet. Tests were performed at simulated in situ geothermal conditions of temperature and pressure.

  11. Calcium inhibits the damaging and compensatory proliferative effects of fatty acids on mouse colon epithelium.

    PubMed

    Wargovich, M J; Eng, V W; Newmark, H L

    1984-07-01

    Intrarectal instillations of the fatty acids (FA), lauric, linoleic or oleic acids induce inflammation and superficial lysis of the colon epithelium. This reaction is followed by increases in colonic mitotic activity and the number of cells engaged in DNA synthesis in compensatory regeneration for the cells that were lost. This explains, in part, the promotional effect of dietary fat in carcinogenesis. Concomitant oral administration of calcium salts, as CaCO3, largely reduced the mitogenic effects of fatty acids on colon epithelium, presumably by forming biologically inert calcium soaps. Calcium soap formation of dietary fatty acids may be one natural mechanism by which colon epithelium cells are protected hence reducing the impact of dietary fat on carcinogenesis for this organ. PMID:6744249

  12. Enhanced formic acid oxidation on polycrystalline platinum modified by spontaneous deposition of gold. Fourier transform infrared spectroscopy studies

    NASA Astrophysics Data System (ADS)

    Cappellari, Paula S.; García, Gonzalo; Florez-Montaño, Jonathan; Barbero, Cesar A.; Pastor, Elena; Planes, Gabriel A.

    2015-11-01

    Formic acid and adsorbed carbon monoxide electrooxidation on polycrystalline Pt and Au-modified Pt surfaces were studied by cyclic voltammetry, lineal sweep voltammetry and in-situ Fourier transform infrared spectroscopy techniques. With this purpose, a polycrystalline Pt electrode was modified by spontaneous deposition of gold atoms, achieving a gold surface coverage (θ) in the range of 0 ≤ θ ≤ 0.47. Results indicate the existence of two main pathways during the formic acid oxidation reaction, i.e. dehydration and dehydrogenation routes. At higher potentials than 0.5 V the dehydrogenation pathway appears to be the operative at both Pt and Au electrodes. Meanwhile, the dehydration reaction is the main pathway for Pt at lower potentials than 0.5 V. It was found that reaction routes are easily tuned by Au deposition on the Pt sites responsible for the formic acid dehydration reaction, and hence for the catalytic formation of adsorbed carbon monoxide. Gold deposition on these Pt open sites produces an enhanced activity toward the HCOOH oxidation reaction. In general terms, the surface inhibition of the reaction by adsorbed intermediates (indirect pathway) is almost absent at gold-modified Pt electrodes, and therefore the direct pathway appears as the main route during the formic acid electrooxidation reaction.

  13. Amelioration of both early and late radiation-induced damage to pig skin by essential fatty acids

    SciTech Connect

    Hopewell, J.W.; Van den Aardweg, G.J.M.J.; Morris, G.M.

    1994-12-01

    To evaluate the possible role of essential fatty acids, specifically gamma-linolenic and eicosapentaenoic acid, in the amelioration of early and late radiation damage to the skin. Skin sites on the flank of 22-25 kg female large white pigs were irradiated with either single or fractionated doses (20 F/28 days) of {beta}-rays from 22.5 mm diameter {sup 90}Sr/{sup 90}Y plaques at a dose rate of {approximately}3 Gy/min. Essential fatty acids were administered orally in the form of two {open_quotes}active{close_quotes} oils, So-1100 and So-5407, which contained gamma-linolenic acid and a mixture of that oil with eicosapentaenoic acid, respectively. Oils (1.5-6.0 ml) were given daily for 4 weeks prior, both 4 weeks prior and 10-16 weeks after, or in the case of one single dose study, just for 10 weeks after irradiation. Control animals received a {open_quotes}placebo{close_quotes} oil, So-1129, containing no gamma linolenic acid or eicosapentaenoic acid over similar time scales before and after irradiation. Acute and late skin reactions were assessed visually and the dose-related incidence of a specific reaction used to compare the effects of different treatment schedules. A reduction in the severity of both the early and late radiation reactions in the skin was only observed when {open_quotes}active{close_quotes} oils were given over the time course of the expression of radiation damage. Prior treatment with oils did not modify the radiation reaction. A 3.0 ml daily dose of either So-1100 or So-5407 given prior to, but also after irradiation with single and fractionated doses of {beta}-rays produced the most significant modification to the radiation reactions, effects consistent with dose modification factors between 1.06-1.24 for the acute reactions of bright red erythema and/or moist desquamation, and of 1.14-1.35 for the late reactions of dusky/mauve erythema and dermal necrosis. 38 refs., 5 tabs.

  14. Effect of deposition method and substrate surface quality on laser-induced damage threshold for repetitive 13-ns and 130-fs pulses

    NASA Astrophysics Data System (ADS)

    Melninkaitis, Andrius; Rakickas, Tomas; Miksys, Darius; Grigonis, Rimantas; Sirutkaitis, Valdas; Skrebutenas, Alfridas; Buzelis, Rytis; Drazdys, Ramutis; Abromavicius, Giedrius; Juskenas, Remigijus; Selskis, Algirdas

    2005-02-01

    A comparison of laser induced damage thresholds (LIDT) of ion assisted deposition (IAD) and standard electron beam deposition dielectric coatings on BK7 glass with different surface roughness was performed. Five types of high reflectance mirrors at 800 nm and two types of high reflectance mirrors at 1064 nm were tested. Mirror coatings were made of ZrO2 and SiO2. Automated LIDT measurements were performed according to the requirements of current ISO 11254-2 standard. Two lasers were used for the measurements: Nd:YAG (l = 1064 nm, t = 13 ns) and Ti:Sapphire (l = 800 nm, t = 130 fs ). All measurements were performed at 1-kHz pulse repetition rate (S-on-1 test). A fixed spot size was used for each laser. For 1064 nm it was ~ 70 um and for 800 nm ~ 500 um. The damage morphology and structure of coatings were characterized by an atomic force microscopy (AFM), Nomarski microscopy and X-ray diffraction (XRD).

  15. Protective effect of ellagic acid and pumpkin seed oil against methotrexate-induced small intestine damage in rats.

    PubMed

    El-Boghdady, Noha A

    2011-12-01

    Gastrointestinal toxicity is one of the most serious side effects in the methotrexate (MTX) treatment. This study was designed to investigate whether ellagic acid (EA) and/or pumpkin seed oil (PSO) had a protective effect on MTX-induced small intestine damage. Forty albino rats were randomized into five groups of 8 rats each. Group I served as a normal control group. In Group II, MTX was administered as a single dose (20 mg/kg) intraperitoneally. Groups III, IV and V were pre-treated respectively with either PSO (40 mg/kg), EA (10 mg/kg) or 0.2% DMSO (vehicle control) orally every day by gavage for 5 days and then they received MTX. All animals were sacrificed 5 days after the intraperitoneal injection of MTX for histopathological examination, estimation of serum prostaglandin E2 (PGE2) level, assay of tissue malondialdehyde (MDA), reduced glutathione (GSH) and nitric oxide (NO) levels and myloperoxidase (MPO), xanthine oxidase (XO) and adenosine deaminase (AD) activities. Administration of EA and/or PSO decreased the intestinal damage, PGE2, MDA and NO levels and MPO, XO and AD activities and increased GSH level. These results suggest that EA and PSO protect the small intestine of rats from MTX-induced damage through their antioxidant and anti-inflammatory effects and thus have potential as a promising drug in the prevention of undesired side effects of MTX. PMID:22329239

  16. Citric acid improves lead (pb) phytoextraction in brassica napus L. by mitigating pb-induced morphological and biochemical damages.

    PubMed

    Shakoor, Muhammad Bilal; Ali, Shafaqat; Hameed, Amjad; Farid, Mujahid; Hussain, Sabir; Yasmeen, Tahira; Najeeb, Ullah; Bharwana, Saima Aslam; Abbasi, Ghulam Hasan

    2014-11-01

    Phytoextraction is an environmentally friendly and a cost-effective strategy for remediation of heavy metal contaminated soils. However, lower bioavailability of some of the metals in polluted environments e.g. lead (Pb) is a major constraint of phytoextraction process that could be overcome by applying organic chelators. We conducted a glasshouse experiment to evaluate the role of citric acid (CA) in enhancing Pb phytoextraction. Brassica napus L. seedlings were grown in hydroponic media and exposed to various treatments of Pb (50 and 100 μM) as alone or in combination with CA (2.5mM) for six weeks. Pb-induced damage in B. napus toxicity was evident from elevated levels of malondialdehyde (MDA) and H2O2 that significantly inhibited plant growth, biomass accumulation, leaf chlorophyll contents and gas exchange parameters. Alternatively, CA application to Pb-stressed B. napus plants arrested lipid membrane damage by limiting MDA and H2O2 production and by improving antioxidant enzyme activities. In addition, CA significantly increased the Pb accumulation in B. napus plants. The study concludes that CA has a potential to improve Pb phytoextraction without damaging plant growth. PMID:25164201

  17. Using shaped pulses to probe energy deposition during laser-induced damage of SiO2 surfaces

    SciTech Connect

    Carr, C W; Cross, D; Feit, M D; Bude, J D

    2008-10-24

    Laser-induced damage initiation in silica has been shown to follow a power-law behavior with respect to pulse-length. Models based on thermal diffusion physics can successfully predict this scaling and the effect of pulse shape for pulses between about 3ns and 10ns. In this work we use sophisticated new measurement techniques and novel pulse shape experiments to test the limits of this scaling. We show that simple pulse length scaling fails for pulses below about 3ns. Furthermore, double pulse initiation experiments suggest that energy absorbed by the first pulse is lost on time scales much shorter than would be predicted for thermal diffusion. This time scale for energy loss can be strongly modulated by maintaining a small but non-zero intensity between the pulses. By producing damage with various pulse shapes and pulse trains it is demonstrated that the properties of any hypothetical thermal absorber become highly constrained.

  18. Nutritional Manipulation of Primate Retinas, V: Effects of Lutein, Zeaxanthin, and n–3 Fatty Acids on Retinal Sensitivity to Blue-Light–Induced Damage

    PubMed Central

    Barker, Felix M.; Snodderly, D. Max; Johnson, Elizabeth J.; Schalch, Wolfgang; Koepcke, Wolfgang; Gerss, Joachim

    2011-01-01

    Purpose. Blue-light photooxidative damage has been implicated in the etiology of age-related macular degeneration (AMD). The macular pigment xanthophylls lutein (L) and zeaxanthin (Z) and n–3 fatty acids may reduce this damage and lower the risk of AMD. This study investigated the effects of the lifelong absence of xanthophylls followed by L or Z supplementation, combined with the effects of n–3 fatty acid deficiency, on acute blue-light photochemical damage. Methods. Subjects included eight rhesus monkeys with no lifelong intake of xanthophylls and no detectable macular pigment. Of these, four had low n–3 fatty acid intake and four had adequate intakes. Control subjects had typical L, Z, and n–3 fatty acid intake. Retinas received 150-μm-diameter exposures of low-power 476-nm laser light at 0.5 mm (∼2°) eccentricity, which is adjacent to the macular pigment peak, and parafoveally at 1.5 mm (∼6°). Exposures of xanthophyll-free animals were repeated after supplementation with pure L or Z for 22 to 28 weeks. Ophthalmoscopically visible lesion areas were plotted as a function of exposure energy, with greater slopes of the regression lines indicating greater sensitivity to damage. Results. In control animals, the fovea was less sensitive to blue-light–induced damage than the parafovea. Foveal protection was absent in xanthophyll-free animals but was evident after supplementation. In the parafovea, animals low in n–3 fatty acids showed greater sensitivity to damage than animals with adequate levels. Conclusions. After long-term xanthophyll deficiency, L or Z supplementation protected the fovea from blue light–induced damage, whereas adequate n–3 fatty acid levels reduced the damage in the parafovea. PMID:21245404

  19. Spatial distribution of damage around faults in the Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah: A mechanical analog for faulting in pyroclastic deposits on Mars

    USGS Publications Warehouse

    Okubo, Chris H.

    2012-01-01

    Volcanic ash is thought to comprise a large fraction of the Martian equatorial layered deposits and much new insight into the process of faulting and related fluid flow in these deposits can be gained through the study of analogous terrestrial tuffs. This study identifies a set of fault-related processes that are pertinent to understanding the evolution of fault systems in fine-grained, poorly indurated volcanic ash by investigating exposures of faults in the Miocene-aged Joe Lott Tuff Member of the Mount Belknap Volcanics, Utah. The porosity and granularity of the host rock are found to control the style of localized strain that occurs prior to and contemporaneous with faulting. Deformation bands occur in tuff that was porous and granular at the time of deformation, while fractures formed where the tuff lost its porous and granular nature due to silicic alteration. Non-localized deformation of the host rock is also prominent and occurs through compaction of void space, including crushing of pumice clasts. Significant off-fault damage of the host rock, resembling fault pulverization, is recognized adjacent to one analog fault and may reflect the strain rate dependence of the resulting fault zone architecture. These findings provide important new guidelines for future structural analyses and numerical modeling of faulting and subsurface fluid flow through volcanic ash deposits on Mars.

  20. Local abnormalities of coagulation and fibrinolytic pathways that promote alveolar fibrin deposition in the lungs of baboons with diffuse alveolar damage.

    PubMed Central

    Idell, S; Peters, J; James, K K; Fair, D S; Coalson, J J

    1989-01-01

    Because alveolar fibrin is a prominent histologic feature of diffuse lung injury in baboons, we hypothesized that local abnormalities of pathways of fibrin turnover would favor fibrin deposition in the alveolar space. To test this hypothesis, procoagulant and fibrinolytic activities were characterized in serial bronchoalveolar lavage (BAL) of baboons with evolving diffuse alveolar damage (DAD) induced by exposure to 100% O2. BAL procoagulant activity, characterized mainly as the tissue factor-Factor VII complex, was markedly increased after induction of DAD. Extrinsic pathway inhibitor was likewise increased in BAL during evolving DAD but was insufficient to control coagulation. Urokinase-like fibrinolytic activity was usually detectable in baseline BAL but was undetectable after 7 d of O2. DAD BAL contained significantly increased plasminogen levels, plasmin inhibitor activity sufficient to neutralize all plasmin produced by BAL plasminogen activator found in control BAL and detectable plasminogen activator inhibitor-1. Antiplasmin activity was due, in part, to increased alpha 2-antiplasmin. These changes correlated with quantitatively increased alveolar fibrin deposition demonstrated by histologic and morphometric analyses. Multiple abnormalities of pathways of fibrin turnover occur concurrently in the alveolar compartment of the lungs of baboons with DAD, which collectively predispose to diffuse alveolar fibrin deposition. Images PMID:2738151

  1. Comparison among model estimates of critical loads of acidic deposition using different sources and scales of input data.

    PubMed

    McDonnell, T C; Cosby, B J; Sullivan, T J; McNulty, S G; Cohen, E C

    2010-09-01

    The critical load (CL) of acidic atmospheric deposition represents the load of acidity deposited from the atmosphere to the earth's surface at which harmful acidification effects on sensitive biological receptors are thought to occur. In this study, the CL for forest soils was estimated for 27 watersheds throughout the United States using a steady-state mass balance approach based on both national and site-specific data and using different approaches for estimating base cation weathering. Results suggested that the scale and source of input data can have large effects on the calculated CL and that the most important parameter in the steady-state model used to estimate CL is base cation weathering. These results suggest that the data and approach used to estimate weathering must be robust if the calculated CL is to be useful for its intended purpose. PMID:20609503

  2. Long-term recovery of lakes in the Adirondack region of New York to decreases in acidic deposition

    NASA Astrophysics Data System (ADS)

    Waller, Kristin; Driscoll, Charles; Lynch, Jason; Newcomb, Dani; Roy, Karen

    2012-01-01

    After years of adverse impacts to the acid-sensitive ecosystems of the eastern United States, the Acid Rain Program and Nitrogen Budget Program were developed to control sulfur dioxide (SO 2) and nitrogen oxide (NO x) emissions through market-based cap and trade systems. We used data from the National Atmospheric Deposition Program's National Trends Network (NTN) and the U.S. EPA Temporally Integrated Monitoring of Ecosystems (TIME) program to evaluate the response of lake-watersheds in the Adirondack region of New York to changes in emissions of sulfur dioxide and nitrogen oxides resulting from the Acid Rain Program and the Nitrogen Budget Program. TIME is a long-term monitoring program designed to sample statistically selected subpopulations of lakes and streams across the eastern U.S. to quantify regional trends in surface water chemistry due to changes in atmospheric deposition. Decreases in wet sulfate deposition for the TIME lake-watersheds from 1991 to 2007 (-1.04 meq m -2-yr) generally corresponded with decreases in estimated lake sulfate flux (-1.46 ± 0.72 meq m -2-yr), suggesting declines in lake sulfate were largely driven by decreases in atmospheric deposition. Decreases in lake sulfate and to a lesser extent nitrate have generally coincided with increases in acid neutralizing capacity (ANC) resulting in shifts in lakes among ANC sensitivity classes. The percentage of acidic Adirondack lakes (ANC <0 μeq L -1) decreased from 15.5% (284 lakes) to 8.3% (152 lakes) since the implementation of the Acid Rain Program and the Nitrogen Budget Program. Two measures of ANC were considered in our analysis: ANC determined directly by Gran plot analysis (ANC G) and ANC calculated by major ion chemistry (ANC calc = CB - CA). While these two metrics should theoretically show similar responses, ANC calc (+2.03 μeq L -1-yr) increased at more than twice the rate as ANC G (+0.76 μeq L -1-yr). This discrepancy has important implications for assessments of lake recovery

  3. Graphene decorated microelectrodes for simultaneous detection of ascorbic, dopamine, and folic acids by means of chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Namdar, N.; Hassanpour Amiri, M.; Dehghan Nayeri, F.; Gholizadeh, A.; Mohajerzadeh, S.

    2015-09-01

    In this paper, high quality and large area graphene layers were synthesized using thermal chemical vapour deposition on copper foil substrates. We use graphene incorporated electrodes to measure simultaneously ascorbic acid, dopamine and folic acid. Cyclic voltammetry and differential pulse voltammetry methods were used to evaluate electrochemical behaviour of the grown graphene layers. The graphene-modified electrode shows large electrochemical potential difference compared to bare gold electrodes with higher current responses. Also our fabricated electrodes configuration can be used easily for microfluidic analysis.

  4. Acid rain and weathering damage to carbonate building stone: Results of material loss measurements

    SciTech Connect

    Reddy, M.; Youngdahl, C.A.

    1987-01-01

    Marble and limestone specimens were exposed to atmospheric conditions at four eastern U.S. sites. A number of methods were employed for damage assessment; this paper describes the results of chemical and physical measurements of material loss. Good agreement was observed among results obtained with different methods. A rate of surface recession near 15 ..mu..m/y was observed for skyward surfaces of marble tested in North Carolina, and comparable results were obtained at the other test sites. Response of the porous limestone was assessed with greater difficulty; a rate of loss similar to that of marble was inferred. Initial correlations of material loss with environmental factors are briefly discussed.

  5. Acid rain and weathering damage to carbonate building stone: Results of material loss measurements

    SciTech Connect

    Reddy, M.M.; Youngdahl, C.A.

    1986-11-01

    Marble and limestone specimens were exposed to atmospheric conditions at four eastern US sites. A number of methods were employed for damage assessment; this paper describes the results of chemical and physical measurements of material loss. Good agreement was observed among results obtained with different methods. A rate of surface recession near 15 ..mu..m/y was observed for skyward surfaces of marble tested in North Carolina, and comparable results were obtained at the other test sites. Response of the porous limestone was assessed with greater difficulty; a rate of loss similar to that of marble was inferred. Initial correlations of material loss with environmental factors are briefly discussed.

  6. 3D-nanoarchitectured Pd/Ni catalysts prepared by atomic layer deposition for the electrooxidation of formic acid

    PubMed Central

    Assaud, Loïc; Monyoncho, Evans; Pitzschel, Kristina; Allagui, Anis; Petit, Matthieu; Hanbücken, Margrit

    2014-01-01

    Summary Three-dimensionally (3D) nanoarchitectured palladium/nickel (Pd/Ni) catalysts, which were prepared by atomic layer deposition (ALD) on high-aspect-ratio nanoporous alumina templates are investigated with regard to the electrooxidation of formic acid in an acidic medium (0.5 M H2SO4). Both deposition processes, Ni and Pd, with various mass content ratios have been continuously monitored by using a quartz crystal microbalance. The morphology of the Pd/Ni systems has been studied by electron microscopy and shows a homogeneous deposition of granularly structured Pd onto the Ni substrate. X-ray diffraction analysis performed on Ni and NiO substrates revealed an amorphous structure, while the Pd coating crystallized into a fcc lattice with a preferential orientation along the [220]-direction. Surface chemistry analysis by X-ray photoelectron spectroscopy showed both metallic and oxide contributions for the Ni and Pd deposits. Cyclic voltammetry of the Pd/Ni nanocatalysts revealed that the electrooxidation of HCOOH proceeds through the direct dehydrogenation mechanism with the formation of active intermediates. High catalytic activities are measured for low masses of Pd coatings that were generated by a low number of ALD cycles, probably because of the cluster size effect, electronic interactions between Pd and Ni, or diffusion effects. PMID:24605281

  7. DNA-damaging disinfection byproducts: alkylation mechanism of mutagenic mucohalic acids.

    PubMed

    Gómez-Bombarelli, Rafael; González-Pérez, Marina; Arenas-Valgañón, Jorge; Céspedes-Camacho, Isaac Fabián; Calle, Emilio; Casado, Julio

    2011-10-15

    Hydroxyhalofuranones form a group of genotoxic disinfection byproduct (DBP) of increasing interest. Among them, mucohalic acids (3,4-dihalo-5-hydroxyfuran-2(5H)-one, MXA) are known mutagens that react with nucleotides, affording etheno, oxaloetheno, and halopropenal derivatives. Mucohalic acids have also found use in organic synthesis due to their high functionalization. In this work, the alkylation kinetics of mucochloric and mucobromic acids with model nucleophiles aniline and NBP has been studied experimentally. Also, the alkylation mechanism of nucleosides by MXA has been studied in silico. The results described allow us to reach the following conclusions: (i) based on the kinetic and computational evidence obtained, a reaction mechanism was proposed, in which MXA react directly with amino groups in nucleotides, preferentially attacking the exocyclic amino groups over the endocyclic aromatic nitrogen atoms; (ii) the suggested mechanism is in agreement with both the product distribution observed experimentally and the mutational pattern of MXA; (iii) the limiting step in the alkylation reaction is addition to the carbonyl group, subsequent steps occurring rapidly; and (iv) mucoxyhalic acids, the hydrolysis products of MXA, play no role in the alkylation reaction by MXA. PMID:21910489

  8. The deposition of conjugated linoleic acids in eggs of laying hens fed diets varying in fat level and fatty acid profile.

    PubMed

    Raes, Katleen; Huyghebaert, Gerard; De Smet, Stefaan; Nollet, Lode; Arnouts, Sven; Demeyer, Daniel

    2002-02-01

    The objective of this study was to investigate the incorporation of conjugated linoleic acid (CLA) into eggs and its effect on the fatty acid metabolism when layers are fed diets with different fat sources and fat levels. Layers were fed either a low fat diet (LF) or one of three high fat diets based on soybean oil (SB), animal fat (AF) or flaxseed oil (FSO). CLA was added at a concentration of 1 g/100 g feed from two different CLA premixes with a different CLA profile. For the trial, 144 laying hens were allocated to 12 treatments (4 basal fat sources x 3 CLA treatments) with 3 replicates of 4 hens each. No significant differences were observed in feed intake, egg weight, feed conversion or laying rate between chickens fed control and CLA-supplemented diets. Differences in yolk fat, cholesterol or yolk color were not clearly related to the dietary CLA. However, the supplementation of CLA to the diets had clear effects on the fatty acid composition, i.e., a decrease in monounsaturated fatty acids (MUFA) and an increase in saturated fatty acids (SFA) was observed, whereas the polyunsaturated fatty acids (PUFA) content were essentially unaffected. The results suggest that CLA may influence the activity of the desaturases to a different extent in the synthesis of (n-6) and (n-3) long-chain fatty acids. These effects of CLA depend on the level of (n-6) and (n-3) fatty acids available in the feed. The apparent deposition rate (%) is clearly higher for the c9, t11 isomer than for the t10, c12 isomer. Adding CLA to layers diets rich in (n-3) fatty acids produces eggs that could promote the health of the consumer in terms of a higher intake of (n-3) fatty acids and CLA. PMID:11823576

  9. Brooktrout Lake case study: biotic recovery from acid deposition 20 years after the 1990 Clean Air Act Amendments.

    PubMed

    Sutherland, James W; Acker, Frank W; Bloomfield, Jay A; Boylen, Charles W; Charles, Donald F; Daniels, Robert A; Eichler, Lawrence W; Farrell, Jeremy L; Feranec, Robert S; Hare, Matthew P; Kanfoush, Sharon L; Preall, Richard J; Quinn, Scott O; Rowell, H Chandler; Schoch, William F; Shaw, William H; Siegfried, Clifford A; Sullivan, Timothy J; Winkler, David A; Nierzwicki-Bauer, Sandra A

    2015-03-01

    The Adirondack Mountain region is an extensive geographic area (26,305 km(2)) in upstate New York where acid deposition has negatively affected water resources for decades and caused the extirpation of local fish populations. The water quality decline and loss of an established brook trout (Salvelinus fontinalis [Mitchill]) population in Brooktrout Lake were reconstructed from historical information dating back to the late 1880s. Water quality and biotic recovery were documented in Brooktrout Lake in response to reductions of S deposition during the 1980s, 1990s, and 2000s and provided a unique scientific opportunity to re-introduce fish in 2005 and examine their critical role in the recovery of food webs affected by acid deposition. Using C and N isotope analysis of fish collagen and state hatchery feed as well as Bayesian assignment tests of microsatellite genotypes, we document in situ brook trout reproduction, which is the initial phase in the restoration of a preacidification food web structure in Brooktrout Lake. Combined with sulfur dioxide emissions reductions promulgated by the 1990 Clean Air Act Amendments, our results suggest that other acid-affected Adirondack waters could benefit from careful fish re-introduction protocols to initiate the ecosystem reconstruction of important components of food web dimensionality and functionality. PMID:25621941

  10. Long term response of acid-sensitive Vermont Lakes to sulfate deposition

    EPA Science Inventory

    Atmospheric deposition of sulfur can negatively affect the health of lakes and streams, particularly in poorly buffered catchments. In response to the Clean Air Act Amendments, wet deposition of sulfate decreased more than 35% in Vermont between 1990 and 2008. However, most of ...

  11. Initial results from the Pawnee eddy correlation system for acid deposition research

    SciTech Connect

    Zeller, K.; Massman, W.; Stocker, D.; Fox, D.G.; Stellman, D.; Hazlett, D.

    1989-01-01

    The Pawnee grassland eddy correlation dry deposition project is described. Instrumentation, methods of analysis, and initial data and research findings are presented. Data from this eddy correlation system show agreement with previous observations of deposition velocities for atmospheric ozone, NO{sub 2}, and NO{sub x}; micrometeorological theory; and micrometeorological site characteristics.

  12. Seasonal and rainfall-type variations in inorganic ions and dicarboxylic acids and acidity of wet deposition samples collected from subtropical East Asia

    NASA Astrophysics Data System (ADS)

    Tsai, Ying I.; Hsieh, Li-Ying; Kuo, Su-Ching; Chen, Chien-Lung; Wu, Pei-Ling

    2011-07-01

    Rainfall samples were collected over a period of 3 years and 8 months in subtropical East Asia. They are categorized into different rainfall types and analyzed to assess the ionic composition and its effect on the acidity of wet deposition in southern Taiwan. Only 4% of samples had a pH of <5.0, indicating that the study area is not impacted significantly by acid rain. The volume-weighted mean (VWM) pH by rainfall type was Spring Rain 5.74, Typhoon Rain 5.56, Summer Rain 5.46, Typhoon Outer Circulation (TOC) Rain 5.45, Plum Rain 5.32 and Autumn-Winter Rain 5.29. Dilution effects were important to the equivalent ionic concentration of different rainfall types. HCO 3-, SO 42- and Cl - were detected as major anions whereas NH 4+, Na + and Ca 2+ were major cations. CO 2-derived HCO 3- was the major ionic species in all but Typhoon Rain and Spring Rain, in which the major species were Na + and Cl - and Ca 2+, respectively. Excluding HCO 3-, the major species were NH 4+, Na + and Ca 2+ in Plum Rain, the secondary photochemical products SO 42-, NO 3- and NH 4+ in TOC Rain and Summer Rain, and Na + and Ca 2+ in Autumn-Winter Rain. Calculation of arithmetic means showed that dicarboxylic acids contributed between 0.25% and 0.53% of the total ionic concentration and of these, oxalic acid contributed the least (81.3% of the dicarboxylic acid) to TOC Rain and the most (96.1% of the dicarboxylic acid) to Spring Rain, suggestive of long-range transport in the latter. Differences in wet deposition composition were shown to be a result of differences in local emissions and long-range transport (hence of prevailing wind direction) during the period of rainfall and of the frequency and volume of rain that typifies each rainfall type. Principal component analysis (PCA) further revealed that traffic-related and industrial organic and inorganic pollutants, their secondary photochemical products, sea salts, and dust are important contributors to wet deposition. Moreover, the ratio of

  13. Protective effect of anacardic acids from cashew (Anacardium occidentale) on ethanol-induced gastric damage in mice.

    PubMed

    Morais, Talita C; Pinto, Natália B; Carvalho, Karine Maria M B; Rios, Jeison B; Ricardo, Nagila Maria P S; Trevisan, Maria Teresa S; Rao, Vietla S; Santos, Flávia A

    2010-01-01

    Cashew nut-shell liquid and the contained anacardic acids (AAs) have been shown to possess antioxidant, lipoxygenase inhibitory, anti-Helicobacter pylori and antitumor properties. Despite these known effects, hitherto there were no published reports on their likely gastroprotective effects. The present study was designed to verify whether AAs afford gastroprotection against the ethanol-induced gastric damage and to examine the underlying mechanism(s). Gastric damage was induced by intragastric administration of 0.2mL of ethanol (96%). Mice in groups were pretreated orally with AAs (10, 30 and 100mg/kg), misoprostol (50 microg/kg), or vehicle (2% Tween 80 in saline, 10mL/kg), 45min before ethanol administration. They were sacrificed 30min later, the stomachs excised, and the mucosal lesion area (mm(2)) measured by planimetry. Gastroprotection was assessed in relation to inhibition of gastric lesion area. To study the gastroprotective mechanism(s), its relations to capsaicin-sensitive fibers, endogenous prostaglandins, nitric oxide and ATP-sensitive potassium channels were analysed. Treatments effects on ethanol-associated oxidative stress markers GSH, MDA, catalase, SOD, and total nitrate/nitrite levels as an index of NO were measured in gastric tissue. Besides, the effects of AAs on gastric secretory volume and total acidity were analysed in 4-h pylorus-ligated rat. AAs afforded a dose-related gastroprotection against the ethanol damage and further prevented the ethanol-induced changes in the levels of GSH, MDA, catalase, SOD and nitrate/nitrite. However, they failed to modify the gastric secretion or the total acidity. It was observed that the gastroprotection by AAs was greatly reduced in animals pretreated with capsazepine, indomethacin, l-NAME or glibenclamide. These results suggest that AAs afford gastroprotection principally through an antioxidant mechanism. Other complementary mechanisms include the activation of capsaicin-sensitive gastric afferents

  14. Prolonged Subdural Infusion of Kynurenic Acid Is Associated with Dose-Dependent Myelin Damage in the Rat Spinal Cord

    PubMed Central

    Dabrowski, Wojciech; Kwiecien, Jacek M.; Rola, Radoslaw; Klapec, Michal; Stanisz, Greg J.; Kotlinska-Hasiec, Edyta; Oakden, Wendy; Janik, Rafal; Coote, Margaret; Frey, Benicio N.; Turski, Waldemar A.

    2015-01-01

    Background Kynurenic acid (KYNA) is the end stage metabolite of tryptophan produced mainly by astrocytes in the central nervous system (CNS). It has neuroprotective activities but can be elevated in the neuropsychiatric disorders. Toxic effects of KYNA in the CNS are unknown. The aim of this study was to assess the effect of the subdural KYNA infusion on the spinal cord in adult rats. Methods A total of 42 healthy adult rats were randomly assigned into six groups and were infused for 7 days with PBS (control) or 0.0002 pmol/min, 0.01 nmol/min, 0.1 nmol/min, 1 nmol/min, and 10 nmol/min of KYNA per 7 days. The effect of KYNA on spinal cord was determined using histological and electron microscopy examination. Myelin oligodendrocyte glycoprotein (MOG) was measured in the blood serum to assess a degree of myelin damage. Result In all rats continuous long-lasting subdural KYNA infusion was associated with myelin damage and myelin loss that was increasingly widespread in a dose-depended fashion in peripheral, sub-pial areas. Damage to myelin sheaths was uniquely related to the separation of lamellae at the intraperiod line. The damaged myelin sheaths and areas with complete loss of myelin were associated with limited loss of scattered axons while vast majority of axons in affected areas were morphologically intact. The myelin loss-causing effect of KYNA occurred with no necrosis of oligodendrocytes, with locally severe astrogliosis and no cellular inflammatory response. Additionally, subdural KYNA infusion increased blood MOG concentration. Moreover, the rats infused with the highest doses of KYNA (1 and 10 nmol/min) demonstrated adverse neurological signs including weakness and quadriplegia. Conclusions We suggest, that subdural infusion of high dose of KYNA can be used as an experimental tool for the study of mechanisms of myelin damage and regeneration. On the other hand, the administration of low, physiologically relevant doses of KYNA may help to discover the role

  15. National Acid Precipitation Assessment Program: Acidic deposition: An inventory of non-Federal research, monitoring, and assessment information

    SciTech Connect

    Herrick, C.N.

    1990-01-01

    The Acid Precipitation Act of 1990 (Title VII of the Energy Security Act of 1980, P.L. 96-294) established the Interagency Task Force on Acid Precipitation to develop and implement the National Acid Precipitation Assessment Program (NAPAP). The information included in the document was provided to NAPAP's Task Group Leaders and State-of-Science and State-of-Technology authors in July 1989. The early release was intended to assure that the authors would be aware of the information at an early phase in the assessment production process.

  16. A Demonstration of Acid Rain and Lake Acidification: Wet Deposition of Sulfur Dioxide.

    ERIC Educational Resources Information Center

    Goss, Lisa M.

    2003-01-01

    Introduces a science demonstration on the dissolution of sulfuric oxide emphasizing the concept of acid rain which is an environmental problem. Demonstrates the acidification from acid rain on two lake environments, limestone and granite. Includes safety information. (YDS)

  17. Humic substances and trace metals associated with Fe and Al oxides deposited in an acidic mountain stream

    USGS Publications Warehouse

    McKnight, Diane M.; Wershaw, R. L.; Bencala, K.E.; Zellweger, G.W.; Feder, G.L.

    1992-01-01

    Hydrous iron and aluminum oxides are deposited on the streambed in the confluence of the Snake River and Deer Creek, two streams in the Colorado Rocky Mountains. The Snake River is acidic and has high concentrations of dissolved Fe and Al. These metals precipitate at the confluence with the pristine, neutral pH, Deer Creek because of the greater pH (4.5-6.0) in the confluence. The composition of the deposited oxides changes consistently with distance downstream, with the most upstream oxide samples having the greatest Fe and organic carbon content. Fulvic acid accounts for most of the organic content of the oxides. Results indicate that streambed oxides in the confluence are not saturated with respect to their capacity to sorb dissolved humic substances from streamwater. The contents of several trace metals (Mn, Zn, Cu, Pb, Ni and Co) also decrease with distance downstream and are correlated with both the Fe and organic carbon contents. Strong metal-binding sites associated with the sorbed fulvic acid are more than sufficient to account for the trace metal content of the oxides. Complexation of trace metals by sorbed fulvic acid may explain the observed downstream decrease in trace metal content.

  18. Prospective role of ascorbic acid (vitamin C) in attenuating hexavalent chromium-induced functional and cellular damage in rat thyroid.

    PubMed

    Qureshi, Irfan Zia; Mahmood, Tariq

    2010-07-01

    Occupational exposure to toxic heavy metals may render industrial workers with thyroid-related problems. Here, we examined the role of ascorbic acid (vitamin C) against hexavalent chromium Cr (VI)-induced damage in rat thyroid gland. Potassium dichromate (K2Cr2O7) and ascorbic acid doses were 60 microg and 120 mg kg(-1) body wt (intraperitoneally [i.p.]) respectively. Treatment regimens were group I rats, saline treated control; group II, only K2Cr2O7; group III, ascorbic acid 1 hour prior K2Cr2O7; group IV, simultaneous doses of ascorbic acid and K2Cr2O7, and group V, a combined premix dose of ascorbic acid and K2 Cr2O7 (2:1 ratio). Blood samples were taken before dosing the animals and 48 hours post exposure to determine the serum thyroid-stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) concentrations. Toward end of experiment, rats were sacrificed and thyroid glands were processed to evaluate the extent of cellular insult. Results showed significantly increased TSH and decreased FT3 and FT4 concentrations in groups II, III and IV rats as compared to control levels (p < 0.05). In contrast, in group V rats, serum TSH, FT3 and FT4 concentrations neared control concentrations. Histopathologically, protective effect of ascorbic acid was found in group V rats only, where thyroid gland structure neared control thyroid except the follicular size that was decreased (p < 0.05). Follicular density was no different from control. Basal laminae were intact, interfollicular spaces were normal. Colloid retraction and/or reabsorption were reduced maximally. Epithelial cell height was no different from control; epithelial follicular index increased only 1.3 fold, whereas nuclear-cytoplasmic (N/C) ratio was decreased by 14% only. The study indicates that the ascorbic acid may have the potential to protect thyroid gland from chromium toxicity; however, the study warrants further in-depth experimentation to precisely elucidate this role. PMID:20504825

  19. Patterns of wet deposition of acidic matter in Maryland: January-June 1984. Final report

    SciTech Connect

    Maxwell, C.; Bartoshesky, J.; Pfeffer, N.; Campbell, S.

    1987-03-03

    A data base containing precipitation-chemistry data collected by multiple monitoring programs in and around Maryland for the January through June 1984 time period was compiled. Isopleth maps were constructed showing the spatial variation in the precipitation concentrations and depositions of hydrogen ion, sulfate, nitrate, ammonium, calcium, sodium, chloride, potassium, and magnesium. For each parameter, the concentration pattern was very similar to its deposition pattern. The patterns suggest the occurrence of a ridge of high sulfate, nitrate, and hydrogen ion concentrations and depositions extending from south-central Pennsylvania, south into Maryland along the western shore of the Chesapeake Bay.

  20. Protective effects of rosmarinic acid against radiation-induced damage to the hematopoietic system in mice

    PubMed Central

    Xu, Wenqing; Yang, Fujun; Zhang, Yujie; Shen, Xiu

    2016-01-01

    Rosmarinic acid (RA) is an ester of caffeic acid and 3, 4-dihydroxyphenyl lactic acid. It is a potent antioxidant that functions by scavenging free radicals. Here, we used a 30-day survival assay to investigate the radioprotective effects of RA. Mice were treated with RA once per day for 10 consecutive days starting at 3 days before gamma irradiation at 7.5 Gy until 7 days post irradiation. Mice treated with 100 and 200 mg/kg body weight (bw) of RA had 30-day survival rates of 89% and 72%, respectively, compared with 32% in the control group, and the differences were statistically significant (P = 0.0008 and 0.0421, respectively). Spleen colony–forming units (CFU-S), the number of nucleated cells in the bone marrow (BMNC), bone marrow DNA content, and hematological parameters of the peripheral blood were measured to investigate the radioprotective effect of RA on the hematopoietic system. The treatment groups that received RA at 50, 100 and 150 mg/kg bw and whole-body exposure to 5.5 Gy of 137Cs γ- radiation had significantly higher CFU-S, BMNC and DNA content than the irradiation-only group. Assessment of hematological parameters in the peripheral blood showed that the treatment groups receiving RA at doses of 50, 100 and 150 mg/kg bw had higher white blood cell counts, hemoglobin and platelets than the radiation-only group. These results suggested that the administration of RA promoted the recovery of peripheral blood cells in irradiated mice. PMID:27006381

  1. Protective effects of rosmarinic acid against radiation-induced damage to the hematopoietic system in mice.

    PubMed

    Xu, Wenqing; Yang, Fujun; Zhang, Yujie; Shen, Xiu

    2016-07-01

    Rosmarinic acid (RA) is an ester of caffeic acid and 3, 4-dihydroxyphenyl lactic acid. It is a potent antioxidant that functions by scavenging free radicals. Here, we used a 30-day survival assay to investigate the radioprotective effects of RA. Mice were treated with RA once per day for 10 consecutive days starting at 3 days before gamma irradiation at 7.5 Gy until 7 days post irradiation. Mice treated with 100 and 200 mg/kg body weight (bw) of RA had 30-day survival rates of 89% and 72%, respectively, compared with 32% in the control group, and the differences were statistically significant (P = 0.0008 and 0.0421, respectively). Spleen colony-forming units (CFU-S), the number of nucleated cells in the bone marrow (BMNC), bone marrow DNA content, and hematological parameters of the peripheral blood were measured to investigate the radioprotective effect of RA on the hematopoietic system. The treatment groups that received RA at 50, 100 and 150 mg/kg bw and whole-body exposure to 5.5 Gy of (137)Cs γ- radiation had significantly higher CFU-S, BMNC and DNA content than the irradiation-only group. Assessment of hematological parameters in the peripheral blood showed that the treatment groups receiving RA at doses of 50, 100 and 150 mg/kg bw had higher white blood cell counts, hemoglobin and platelets than the radiation-only group. These results suggested that the administration of RA promoted the recovery of peripheral blood cells in irradiated mice. PMID:27006381

  2. Bioactive 1,4-dihydroisonicotinic acid derivatives prevent oxidative damage of liver cells.

    PubMed

    Borovic, Suzana; Tirzitis, Gunars; Tirzite, Dace; Cipak, Ana; Khoschsorur, Gholam A; Waeg, Georg; Tatzber, Franz; Scukanec-Spoljar, Mira; Zarkovic, Neven

    2006-05-10

    1,4-Dihydroisonicotinic acid derivatives (1,4-DHINA) are compounds closely related to derivatives of 1,4-dihydropyridine, a well-known calcium channel antagonists. 1,4-DHINA we used were derived from a well-known antioxidant Diludin. Although some compounds have neuromodulatory or antimutagenic properties, their activity mechanisms are not well known. This study was performed to obtain data on antioxidant and bioprotective activities of: 2,6-dimethyl-3,5-diethoxycarbonyl-1,4-dihydroisonicotinic acid (Ia); sodium 2-(2,6-dimethyl-3,5-diethoxycarbonyl-1,4-dihydropyridine-4-carboxamido)glutamate (Ib) and sodium 2-(2,6-dimethyl-3,5-diethoxycarbonyl-1,4-dihydropyridine-4-carboxamido)ethane-sulphate (Ic). 1,4-DHINA's activities were studied in comparison to Trolox by: N,N-Diphenyl-N'-picrylhydrazyl (DPPH*), deoxyribose degradation, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical scavenging and antioxidative capacity assays; copper-induced lipid peroxidation of cultured rat liver cells (malondialdehyde determination by high performance liquid chromatography and 4-hydroxynonenal-protein conjugates by dot-blot); (3)H-thymidine incorporation and trypan blue assay for liver cells growth and viability. In all assays used Ia was the most potent antioxidant. Ia was also a potent antioxidant at non-toxic concentrations for liver cell cultures. It completely abolished, while Ic only slightly decreased copper-induced lipid peroxidation of liver cells. Thus, antioxidant capacities are important activity principle of Ia, which was even superior to Trolox in the cell cultures used, while activity principles of Ic and Ib remain yet to be determined. PMID:16600211

  3. Hyaluronic acid uptake in the assessment of sinusoidal endothelial cell damage after cold storage and normothermic reperfusion of rat livers.

    PubMed

    Reinders, M E; van Wagensveld, B A; van Gulik, T M; Frederiks, W M; Chamuleau, R A; Endert, E; Klopper, P J

    1996-01-01

    The uptake of hyaluronic acid (HA) was used to assess preservation damage to sinusoidal endothelial cells (SEC) during cold storage and subsequent normothermic reperfusion of rat livers. After 8, 16, 24, and 48 h storage in University of Wisconsin (UW) solution, livers were gravity-flushed via the portal vein with a standard volume of cold UW solution containing 50 micrograms/l HA. The effluent was collected for analysis of HA, aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). The mean uptake of HA at 0 h was 59.1% +/- 4.6% (mean +/- SEM). After 8 h of storage, HA uptake was similar (55.5% +/- 7.3%), whereas after 16 h of storage it was reduced to 34.7% +/- 5.8%. At 24 and 48 h of storage, no uptake of HA was found. In a second series of experiments, livers were stored in UW solution and subsequently reperfused for 90 min with a Krebs-Henseleit solution (37 degrees C) in a recirculating system containing 150 micrograms/l HA. Following 8 h of storage, 34.6% +/- 8.0% of the initial HA concentration was taken up from the perfusate. After 16 and 24 h of storage, no uptake of HA was found. The results of this study indicate that damage to SEC occurs progressively during storage, leading to zero uptake of HA by the rat livers at 24 h of cold ischemia time. Additional reperfusion injury to the SEC was demonstrated by the reduced ability of the SEC to take up HA following normothermic reperfusion. The uptake of exogenous HA in preserved livers, used as a tool to assess SEC injury, enables the detection of early preservation damage. PMID:8875786

  4. APE1-mediated DNA damage repair provides survival advantage for esophageal adenocarcinoma cells in response to acidic bile salts.

    PubMed

    Hong, Jun; Chen, Zheng; Peng, Dunfa; Zaika, Alexander; Revetta, Frank; Washington, M Kay; Belkhiri, Abbes; El-Rifai, Wael

    2016-03-29

    Chronic Gastroesophageal Reflux Disease (GERD) is the main risk factor for the development of Barrett's esophagus (BE) and its progression to esophageal adenocarcinoma (EAC). Accordingly, EAC cells are subjected to high levels of oxidative stress and subsequent DNA damage. In this study, we investigated the expression and role of Apurinic/apyrimidinic endonuclease 1 (APE1) protein in promoting cancer cell survival by counteracting the lethal effects of acidic bile salts (ABS)-induced DNA damage. Immunohistochemistry analysis of human tissue samples demonstrated overexpression of APE1 in more than half of EACs (70 of 130), as compared to normal esophagus and non-dysplastic BE samples (P < 0.01). To mimic in vivo conditions, we treated in vitro cell models with a cocktail of ABS. The knockdown of endogenous APE1 in EAC FLO-1 cells significantly increased oxidative DNA damage (P < 0.01) and DNA single- and double-strand breaks (P < 0.01), whereas overexpression of APE1 in EAC OE33 cells reversed these effects. Annexin V/PI staining indicated that the APE1 expression in OE33 cells protects against ABS-induced apoptosis. In contrast, knockdown of endogenous APE1 in FLO-1 cells increased apoptosis under the same conditions. Mechanistic investigations indicated that the pro-survival function of APE1 was associated with the regulation of stress response c-Jun N-terminal protein kinase (JNK) and p38 kinases. Pharmacological inhibition of APE1 base excision repair (BER) function decreased cell survival and enhanced activation of JNK and p38 kinases by ABS. Our findings suggest that constitutive overexpression of APE1 in EAC may be an adaptive pro-survival mechanism that protects against the genotoxic lethal effects of bile reflux episodes. PMID:26934647

  5. Protective Efficacy of Alpha-lipoic Acid against AflatoxinB1-induced Oxidative Damage in the Liver

    PubMed Central

    Li, Y.; Ma, Q. G.; Zhao, L. H.; Guo, Y. Q.; Duan, G. X.; Zhang, J. Y.; Ji, C.

    2014-01-01

    Alpha-lipoic acid (α-LA) is not only involved in energy metabolism, but is also a powerful antioxidant that can protect against hepatic oxidative stress induced by some drugs, toxins, or under various physiological and pathophysiological conditions. Here, we investigated the effect of α-LA against liver oxidative damage in broilers exposed to aflatoxin B1 (AFB1). Birds were randomly divided into four groups and assigned different diets: basal diet, 300 mg/kg α-LA supplementation in basal diet, diet containing 74 μg/kg AFB1, and 300 mg/kg α-LA supplementation in diet containing 74 μg/kg AFB1, for 3 weeks. The results revealed that the addition of 300 mg/kg α-LA protected against the liver function damage of broilers induced by chronic low dose of AFB1 as estimated by a significant (p<0.05) change in levels of plasma total protein, albumin, alkaline phosphatase and the activities of liver glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase. The histopathological analysis also showed that liver tissues were injured in the AFB1 diet, but this effect was alleviated by the addition of 300 mg/kg α-LA. Additionally, AFB1 induced a profound elevation of oxidative stress in birds, as indicated by an increase in malondialdehyde level, a decrease in glutathione peroxidase activity and a depletion of the glutathione content in the liver. All of these negative effects were inhibited by treatment with α-LA. Our results suggest that the inhibition of AFB1-induced excess production of lipid peroxides and the maintenance of intracellular antioxidant status may play important roles in the protective effects of α-LA against AFB1-induced oxidative damage in the liver. PMID:25050030

  6. Acetyl salicylic acid protected against heat stress damage in chicken myocardial cells and may associate with induced Hsp27 expression.

    PubMed

    Wu, Di; Xu, Jiao; Song, Erbao; Tang, Shu; Zhang, Xiaohui; Kemper, N; Hartung, J; Bao, Endong

    2015-07-01

    We investigated whether acetyl salicylic acid (ASA) protects chicken myocardial cells from heat stress-mediated damage in vivo and whether the induction of Hsp27 expression is connected with this function. Pathological changes, damage-related enzyme levels, and Hsp27 expression were studied in chickens following heat stress (40 ± 1 °C for 0, 1, 2, 3, 5, 7, 10, 15, or 24 h, respectively) with or without ASA administration (1 mg/kg BW, 2 h prior). Appearance of pathological lesions such as degenerations and karyopyknosis as well as the myocardial damage-related enzyme activation indicated that heat stress causes considerable injury to the myocardial cells in vivo. Myocardial cell injury was most serious in chickens exposed to heat stress without prior ASA administration; meanwhile, ASA pretreatment acted protective function against high temperature-induced injury. Hsp27 expression was induced under all experimental conditions but was one-fold higher in the ASA-pretreated animals (0.3138 ± 0.0340 ng/mL) than in untreated animals (0.1437 ± 0.0476 ng/mL) 1 h after heat stress exposure, and such an increase was sustained over the length of the experiment. Our findings indicate that pretreatment with ASA protects chicken myocardial cells from acute heat stress in vivo with almost no obvious side effects, and this protection may involve an enhancement of Hsp27 expression. However, the detailed mechanisms underlying this effect require further investigation. PMID:25956131

  7. APE1-mediated DNA damage repair provides survival advantage for esophageal adenocarcinoma cells in response to acidic bile salts

    PubMed Central

    Hong, Jun; Chen, Zheng; Peng, Dunfa; Zaika, Alexander; Revetta, Frank; Washington, M. Kay; Belkhiri, Abbes; El-Rifai, Wael

    2016-01-01

    Chronic Gastroesophageal Reflux Disease (GERD) is the main risk factor for the development of Barrett's esophagus (BE) and its progression to esophageal adenocarcinoma (EAC). Accordingly, EAC cells are subjected to high levels of oxidative stress and subsequent DNA damage. In this study, we investigated the expression and role of Apurinic/apyrimidinic endonuclease 1 (APE1) protein in promoting cancer cell survival by counteracting the lethal effects of acidic bile salts (ABS)-induced DNA damage. Immunohistochemistry analysis of human tissue samples demonstrated overexpression of APE1 in more than half of EACs (70 of 130), as compared to normal esophagus and non-dysplastic BE samples (P < 0.01). To mimic in vivo conditions, we treated in vitro cell models with a cocktail of ABS. The knockdown of endogenous APE1 in EAC FLO-1 cells significantly increased oxidative DNA damage (P < 0.01) and DNA single- and double-strand breaks (P < 0.01), whereas overexpression of APE1 in EAC OE33 cells reversed these effects. Annexin V/PI staining indicated that the APE1 expression in OE33 cells protects against ABS-induced apoptosis. In contrast, knockdown of endogenous APE1 in FLO-1 cells increased apoptosis under the same conditions. Mechanistic investigations indicated that the pro-survival function of APE1 was associated with the regulation of stress response c-Jun N-terminal protein kinase (JNK) and p38 kinases. Pharmacological inhibition of APE1 base excision repair (BER) function decreased cell survival and enhanced activation of JNK and p38 kinases by ABS. Our findings suggest that constitutive overexpression of APE1 in EAC may be an adaptive pro-survival mechanism that protects against the genotoxic lethal effects of bile reflux episodes. PMID:26934647

  8. Prevention of DNA damage in spores and in vitro by small, acid-soluble proteins from Bacillus species.

    PubMed Central

    Fairhead, H; Setlow, B; Setlow, P

    1993-01-01

    The DNA in dormant spores of Bacillus species is saturated with a group of nonspecific DNA-binding proteins, termed alpha/beta-type small, acid-soluble spore proteins (SASP). These proteins alter DNA structure in vivo and in vitro, providing spore resistance to UV light. In addition, heat treatments (e.g., 85 degrees C for 30 min) which give little killing of wild-type spores of B. subtilis kill > 99% of spores which lack most alpha/beta-type SASP (termed alpha - beta - spores). Similar large differences in survival of wild-type and alpha - beta - spores were found at 90, 80, 65, 22, and 10 degrees C. After heat treatment (85 degrees C for 30 min) or prolonged storage (22 degrees C for 6 months) that gave > 99% killing of alpha - beta - spores, 10 to 20% of the survivors contained auxotrophic or asporogenous mutations. However, alpha - beta - spores heated for 30 min at 85 degrees C released no more dipicolinic acid than similarly heated wild-type spores (< 20% of the total dipicolinic acid) and triggered germination normally. In contrast, after a heat treatment (93 degrees C for 30 min) that gave > or = 99% killing of wild-type spores, < 1% of the survivors had acquired new obvious mutations, > 85% of the spore's dipicolinic acid had been released, and < 1% of the surviving spores could initiate spore germination. Analysis of DNA extracted from heated (85 degrees C, 30 min) and unheated wild-type spores and unheated alpha - beta - spores revealed very few single-strand breaks (< 1 per 20 kb) in the DNA. In contrast, the DNA from heated alpha- beta- spores had more than 10 single-strand breaks per 20 kb. These data suggest that binding of alpha/beta-type SASP to spore DNA in vivo greatly reduces DNA damage caused by heating, increasing spore heat resistance and long-term survival. While the precise nature of the initial DNA damage after heating of alpha- beta- spores that results in the single-strand breaks is not clear, a likely possibility is DNA depurination. A

  9. Role of intracellular calcium and NADPH oxidase NOX5-S in acid-induced DNA damage in Barrett's cells and Barrett's esophageal adenocarcinoma cells

    PubMed Central

    Li, Dan

    2014-01-01

    Mechanisms whereby acid reflux may accelerate the progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. Acid and reactive oxygen species (ROS) have been reported to cause DNA damage in Barrett's cells. We have previously shown that NADPH oxidase NOX5-S is responsible for acid-induced H2O2 production in Barrett's cells and in EA cells. In this study we examined the role of intracellular calcium and NADPH oxidase NOX5-S in acid-induced DNA damage in a Barrett's EA cell line FLO and a Barrett's cell line CP-A. We found that pulsed acid treatment significantly increased tail moment in FLO and CP-A cells and histone H2AX phosphorylation in FLO cells. In addition, acid treatment significantly increased intracellular Ca2+ in FLO cells, an increase that is blocked by Ca2+-free medium with EGTA and thapsigargin. Acid-induced increase in tail moment was significantly decreased by NADPH oxidase inhibitor diphenylene iodonium in FLO cells, and by blockade of intracellular Ca2+ increase or knockdown of NOX5-S with NOX5 small-interfering RNA (siRNA) in FLO and CP-A cells. Acid-induced increase in histone H2AX phosphorylation was significantly decreased by NOX5 siRNA in FLO cells. Conversely, overexpression of NOX5-S significantly increased tail moment and histone H2AX phosphorylation in FLO cells. We conclude that pulsed acid treatment causes DNA damage via increase of intracellular calcium and activation of NOX5-S. It is possible that in BE acid reflux increases intracellular calcium, activates NOX5-S, and increases ROS production, which causes DNA damage, thereby contributing to the progression from BE to EA. PMID:24699332

  10. Phenolic acid protects of renal damage induced by ochratoxin A in a 28-days-oral treatment in rats.

    PubMed

    Cariddi, L N; Escobar, F M; Sabini, M C; Campra, N A; Bagnis, G; Decote-Ricardo, D; Freire-de-Lima, C G; Mañas, F; Sabini, L I; Dalcero, A M

    2016-04-01

    The present study aimed to characterize the chlorogenic acid (ChlA) capacity to reverse the toxic effects induced by ochratoxin A (OTA) in a subacute toxicity test in rats. Male Wistar rats were fed orally by gavage for 28 days with OTA (0.4mg/kg bw/day), ChlA (5mg/kg bw/day) or the combination OTA (0.4mg/kg bw/day)+ChlA (5mg/kg bw/day). No deaths, no decrease in feed intake or body weight in any experimental group were recorded. The negative control group and the animals treated with ChlA alone showed no changes in any parameters evaluated. In OTA-treated group significant changes such as decrease in urine volume, proteinuria, occult blood, increase in serum creatinine values; decrease in absolute and relative kidney weight and characteristics histopathological lesions that indicated kidney damage were observed. However, limited effect on oxidative stress parameters were detected in kidneys of OTA-treated group. Animals treated with the combination OTA+ChlA were showed as negative control group in the evaluation of several parameters of toxicity. In conclusion, ChlA, at given concentration, improved biochemical parameters altered in urine and serum and pathological damages in kidneys induced by OTA exposure, showing a good protective activity, but not by an apparent antioxidant mechanism. PMID:26987112

  11. Prophylactic acetylsalicylic acid attenuates the inflammatory response but fails to protect exercise-induced liver damage in exercised rats.

    PubMed

    Huang, Kuo-Chin; Chiu, Yi-Han; Liao, Kuang-Wen; Ke, Chun-Yen; Lee, Chung-Jen; Chao, Yann-Fen C; Lee, Ru-Ping

    2016-09-01

    This study evaluated the effects of acetylsalicylic acid (ASA) on exercise-induced inflammatory response, muscle damage, and liver injury in rats. Wistar-Kyoto (WKY) rats were divided into six groups: control (C), exercise (E), C+20mg ASA, E+20mg ASA, C+100mg/kg ASA, and E+100mg ASA groups. ASA or a vehicle was orally administered through gavage 1h before a treadmill test. Upon trial completion, blood was drawn at 1, 12, and 24h for biochemical analysis, and livers were excised at 24h for a histological assessment. Our results revealed that 100mg/kg ASA significantly reduced interleukin (IL)-6 and tumor necrosis factor (TNF)-α levels in the E groups; however, the IL-10 level was considerably increased. Moreover, aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels and histological hepatic damage increased significantly in the E+100mg ASA group compared with the corresponding changes in the E group. These results suggest that the prophylactic administration of particularly high-dose ASA alleviates exercise-induced inflammatory response but exacerbates liver injury. PMID:27262381

  12. Comparison of the chronic effects of ribavirin and caffeic acid phenethyl ester (CAPE) on pancreatic damage and hepatotoxicity

    PubMed Central

    Motor, Sedat; Alp, Harun; Şenol, Serkan; Pınar, Neslihan; Motor, Vicdan Köksaldı; Kaplan, İbrahim; Alp, Ayşe; Gökçe, Cumali

    2014-01-01

    This study was aimed to comparison of the effects of the chronic use of the Ribavirin and caffeic acid phenethyl ester (CAPE) on the pancreatic damage and hepatotoxicity in rats. Methods: The rats were given orally 30 mg/kg/day doses of Ribavirin for 30 days, and intraperitoneally 10 μmol/kg doses of CAPE. The 37 rats were divided into 4 groups: (I) Control (n=7), (II) Ribavirin (R) (n=10), (III) CAPE (n=10), and (IV) R+CAPE (n=10). Results: Ribavirin and CAPE yielded similar results in terms of Serum, total antioxidant status (TAS), total oxidant status (TOS), amylase, lipase, and insulin compared to the control group. However, while Ribavirin provided similar results with the control group in terms of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) enzymes, the CAPE group had elevated AST and ALT levels compared to the control group. Histopathologic evaluations revealed that CAPE or Ribavirin had no degenerative effects on both the pancreas and liver tissues. In this way, the biochemical results were confirmed by the histopathologic results. Conclusion: It can be concluded that Ribavirin does not lead to any pancreatic damage and hepatotoxicity, and has more beneficial effects than CAPE on especially liver tissue. PMID:24955174

  13. Mutagenicity and DNA-damaging potential of clenbuterol and its metabolite 4-amino-3,5-dichlorobenzoic acid in vitro.

    PubMed

    Vulić, Ana; Durgo, Ksenija; Pleadin, Jelka; Herceg, Luka; Kopjar, Nevenka

    2015-03-01

    The aim of this study was to evaluate in vitro toxicity of clenbuterol and its metabolite 4-amino-3,5-dichlorobenzoic acid. Cytotoxicity and pro-oxidative effect of both compounds were studied on human colon adenocarcinoma cell line SW 480. No significant cytotoxic effect of either compound was observed. Results of an Ames test on Salmonella typhimurium did not indicate mutagenic activity of clenbuterol on TA 98 and TA 100 strains, regardless of metabolic activation. Potential mutagenic effects of the highest clenbuterol concentration (2500 ng/ml) were observed on the TA 1535 strain. The obtained results of alkaline comet assay on isolated human lymphocytes suggested that both compounds induced an increase of primary DNA damage in a concentration-dependent manner. 4-ADBA was a slightly more potent inducer of primary DNA damage as compared to clenbuterol. Chromosomal aberration analysis showed that clenbuterol caused a statistically significant increase in the total number of aberrant cells only at the highest concentration tested (3% vs. 0.7% in the negative control). The results of this study might represent a solid frame for designing and planning future studies with both compounds, which should further clarify their mechanisms of action and genotoxic/cytogenetic effects relevant for human risk assessment. PMID:25595371

  14. Antibacterial Activity of Shikimic Acid from Pine Needles of Cedrus deodara against Staphylococcus aureus through Damage to Cell Membrane

    PubMed Central

    Bai, Jinrong; Wu, Yanping; Liu, Xiaoyan; Zhong, Kai; Huang, Yina; Gao, Hong

    2015-01-01

    Shikimic acid (SA) has been reported to possess antibacterial activity against Staphylococcus aureus, whereas the mode of action of SA is still elusive. In this study, the antibacterial activity and mechanism of SA toward S. aureus by cell membrane damage was investigated. After SA treatment, massive K+ and nucleotide leakage from S. aureus, and a significant change in the membrane potential was observed, suggesting SA may act on the membrane by destroying the cell membrane permeability. Through transmission electron microscopic observations we further confirmed that SA can disrupt the cell membrane and membrane integrity. Meanwhile, SA was found to be capable of reducing the membrane fluidity of the S. aureus cell. Moreover, the fluorescence experiments indicated that SA could quench fluorescence of Phe residues of the membrane proteins, thus demonstrating that SA can bind to S. aureus membrane proteins. Therefore, these results showed the antibacterial activity of SA against S. aureus could be caused by the interactions of SA with S. aureus membrane proteins and lipids, resulting in causing cell membrane dysfunction and bacterial damage or even death. This study reveals the potential use of SA as an antibacterial agent. PMID:26580596

  15. Acid deposition coverage in five North American newspapers, 1979-1982

    SciTech Connect

    Kauffeld, J.A.; Fortner, R.W.

    1987-01-01

    Daily newspapers in some areas receiving acid rain, in some areas reported to be producing acid rain, and in some areas apparently ''neutral'' in the issue were content analyzed for their coverage of acid rain between 1979 and 1982. Of the five papers, the greatest amount of coverage was in the Cleveland Plain Dealer and the Toronto Globe and Mail. Coverage of acid rain effects was greatest in the Washington Post, as was the number of items suggesting remedies for the problem. Articles from papers in areas receiving acid rain contained more indications of urgency than those from areas blamed for the problem.

  16. Controls on suppression of methane flux from a peat bog subjected to simulated acid rain sulfate deposition

    NASA Astrophysics Data System (ADS)

    Gauci, Vincent; Dise, Nancy; Fowler, David

    2002-01-01

    The effect of acid rain SO42- deposition on peatland CH4 emissions was examined by manipulating SO42- inputs to a pristine raised peat bog in northern Scotland. Weekly pulses of dissolved Na2SO4 were applied to the bog over two years in doses of 25, 50, and 100 kg S ha-1 yr-1, reflecting the range of pollutant S deposition loads experienced in acid rain-impacted regions of the world. CH4 fluxes were measured at regular intervals using a static chamber/gas chromatographic flame ionization detector method. Total emissions of CH4 were reduced by between 21 and 42% relative to controls, although no significant differences were observed between treatments. Estimated total annual fluxes during the second year of the experiment were 16.6 g m-2 from the controls and (in order of increasing SO42- dose size) 10.7, 13.2, and 9.8 g m-2 from the three SO42- treatments, respectively. The relative extent of CH4 flux suppression varied with changes in both peat temperature and peat water table with the largest suppression during cool periods and episodes of falling water table. Our findings suggest that low doses of SO42- at deposition rates commonly experienced in areas impacted by acid rain, may significantly affect CH4 emissions from wetlands in affected areas. We propose that SO42- from acid rain can stimulate sulfate-reducing bacteria into a population capable of outcompeting methanogens for substrates. We further propose that this microbially mediated interaction may have a significant current and future effect on the contribution of northern peatlands to the global methane budget.

  17. Recognition of damage-associated molecular patterns related to nucleic acids during inflammation and vaccination

    PubMed Central

    Jounai, Nao; Kobiyama, Kouji; Takeshita, Fumihiko; Ishii, Ken J.

    2012-01-01

    All mammalian cells are equipped with large numbers of sensors for protection from various sorts of invaders, who, in turn, are equipped with molecules containing pathogen-associated molecular patterns (PAMPs). Once these sensors recognize non-self antigens containing PAMPs, various physiological responses including inflammation are induced to eliminate the pathogens. However, the host sometimes suffers from chronic infection or continuous injuries, resulting in production of self-molecules containing damage-associated molecular patterns (DAMPs). DAMPs are also responsible for the elimination of pathogens, but promiscuous recognition of DAMPs through sensors against PAMPs has been reported. Accumulation of DAMPs leads to massive inflammation and continuous production of DAMPs; that is, a vicious circle leading to the development of autoimmune disease. From a vaccinological point of view, the accurate recognition of both PAMPs and DAMPs is important for vaccine immunogenicity, because vaccine adjuvants are composed of several PAMPs and/or DAMPs, which are also associated with severe adverse events after vaccination. Here, we review as the roles of PAMPs and DAMPs upon infection with pathogens or inflammation, and the sensors responsible for recognizing them, as well as their relationship with the development of autoimmune disease or the immunogenicity of vaccines. PMID:23316484

  18. Acid deposition: atmospheric processes in eastern North America, a review of current scientific understanding

    SciTech Connect

    Not Available

    1983-01-01

    There is no observational evidence of a strong nonlinearity in the relationship between annual average total emissions and total deposition of sulfur in eastern North America. The finding is supported by theoretical calculations using the best available laboratory measurements of photochemical rate parameters. Currently available models of long-range atmospheric transport and transformation are not sufficiently developed to assess relationships between emissions from specific sources and deposition at specific receptor sites with high reliability.

  19. Acoustic and Ultrasonic Spectral Evolution in Pre- and Post-Damage Self-Healing Poly (Ethylene Co-Methacrylic Acid) Ionomer Samples

    NASA Astrophysics Data System (ADS)

    Buckley, Jonathan; Pestka, Kenneth, II; Kalista, Stephen

    We measured the pre- and post-damage resonant spectra of several self-healing ionomer samples composed of poly (ethylene co-methacrylic acid) (EMAA). The post-damage results indicate significant time-dependent variation in the acoustic and ultrasonic resonant spectral waveforms of these self-healing samples. These results are consistent with other recent experiments that demonstrate time evolution of resonant frequencies and associated quality factors within samples of post-damage EMAA ionomers. However, in our experiments it was found that, in some circumstances, the quality factors and associated resonant frequencies can exhibit time-dependent variation both before and after external damage. By quantifying time-dependent variations in the spectra of undamaged samples, including quality factor, resonant frequency and spectral waveform, we demonstrate a method to isolate changes in the resonant spectra that are present solely due to the post-damage healing behavior of these EMAA ionomers.

  20. High Elevation Lakes of the Western US: Are we Studying Systems Recovering from Excess Atmospheric Deposition of Acids and Nutrients?

    NASA Astrophysics Data System (ADS)

    Sickman, J. O.

    2011-12-01

    Instrumental records and monitoring of high elevation lakes began in most areas of the western US in the early 1980s. Much effort has been devoted to detecting changes in these aquatic ecosystems resulting from increased atmospheric deposition of acids and nutrients. However, there is growing evidence that thresholds for atmospheric pollutants were crossed much earlier in the 20th Century and that some of the subsequent hydrochemical and ecological changes observed in these lakes may be the result of recovery from earlier atmospheric forcing. We examine responses of high elevation lakes to atmospheric deposition on annual to century timescales using data from a 29-year study of Emerald Lake (Sequoia National Park) and paleolimnological analyses of other high elevation lakes incorporating diatom species analyses and geochemical proxies for fossil-fuel burning. At Emerald Lake, we have observed multiple transitions between nitrogen and phosphorus limitation of phytoplankton, the earliest of which occurred in the beginning of the 1980s and may be the result of reduction in N deposition due to the Clean Air Act. Critical loads analyses incorporating diatom species in lake sediments suggest that thresholds for N deposition were crossed in the period of 1950-1980 in the Rocky Mountains and likely much earlier, 1900-1920, in the Sierra Nevada. Diatom species composition is strongly controlled by acid neutralizing capacity (ANC) in the Sierra Nevada and we have observed a pronounced decline and recovery of ANC over the period of 1920-1980 in some Sierra Nevada lakes that coincides with the abundance of spheroidal carbonaceous particles (i.e., a diagnostic tracer of fossil fuel combustion) preserved in lake sediments; these patterns appear to be driven by increased emissions of oxidized N and S in the mid-20th Century and reductions in acid precursor levels caused by the Clean Air Act in the 1970s. Thus, when interpreting observational records from western high elevation

  1. Comparison of gate dielectric plasma damage from plasma-enhanced atomic layer deposited and magnetron sputtered TiN metal gates

    SciTech Connect

    Brennan, Christopher J.; Neumann, Christopher M.; Vitale, Steven A.

    2015-07-28

    Fully depleted silicon-on-insulator transistors were fabricated using two different metal gate deposition mechanisms to compare plasma damage effects on gate oxide quality. Devices fabricated with both plasma-enhanced atomic-layer-deposited (PE-ALD) TiN gates and magnetron plasma sputtered TiN gates showed very good electrostatics and short-channel characteristics. However, the gate oxide quality was markedly better for PE-ALD TiN. A significant reduction in interface state density was inferred from capacitance-voltage measurements as well as a 1200× reduction in gate leakage current. A high-power magnetron plasma source produces a much higher energetic ion and vacuum ultra-violet (VUV) photon flux to the wafer compared to a low-power inductively coupled PE-ALD source. The ion and VUV photons produce defect states in the bulk of the gate oxide as well as at the oxide-silicon interface, causing higher leakage and potential reliability degradation.

  2. Comparison of gate dielectric plasma damage from plasma-enhanced atomic layer deposited and magnetron sputtered TiN metal gates

    NASA Astrophysics Data System (ADS)

    Brennan, Christopher J.; Neumann, Christopher M.; Vitale, Steven A.

    2015-07-01

    Fully depleted silicon-on-insulator transistors were fabricated using two different metal gate deposition mechanisms to compare plasma damage effects on gate oxide quality. Devices fabricated with both plasma-enhanced atomic-layer-deposited (PE-ALD) TiN gates and magnetron plasma sputtered TiN gates showed very good electrostatics and short-channel characteristics. However, the gate oxide quality was markedly better for PE-ALD TiN. A significant reduction in interface state density was inferred from capacitance-voltage measurements as well as a 1200× reduction in gate leakage current. A high-power magnetron plasma source produces a much higher energetic ion and vacuum ultra-violet (VUV) photon flux to the wafer compared to a low-power inductively coupled PE-ALD source. The ion and VUV photons produce defect states in the bulk of the gate oxide as well as at the oxide-silicon interface, causing higher leakage and potential reliability degradation.

  3. Endoplasmic reticulum stress involved in high-fat diet and palmitic acid-induced vascular damages and fenofibrate intervention

    SciTech Connect

    Lu, Yunxia; Cheng, Jingjing; Chen, Li; Li, Chaofei; Chen, Guanjun; Gui, Li; Shen, Bing; Zhang, Qiu

    2015-02-27

    Fenofibrate (FF) is widely used to lower blood lipids in clinical practice, but whether its protective effect on endothelium-dependent vasodilatation (EDV) in thoracic aorta is related with endoplasmic reticulum (ER) stress remains unknown. In this study, female Sprauge Dawley rats were divided into standard chow diets (SCD), high-fat diets (HFD) and HFD plus FF treatment group (HFD + FF) randomly. The rats of latter two groups were given HFD feeding for 5 months, then HFD + FF rats were treated with FF (30 mg/kg, once daily) via gavage for another 2 months. The pathological and tensional changes, protein expression of eNOS, and ER stress related genes in thoracic aorta were measured. Then impacts of palmitic acid (PA) and FF on EDV of thoracic aorta from normal female SD rats were observed. Ultimately the expression of ER stress related genes were assessed in primary mouse aortic endothelial cells (MAEC) treated by fenofibric acid (FA) and PA. We found that FF treatment improved serum lipid levels and pathological changes in thoracic aorta, accompanied with decreased ER stress and increased phosphorylation of eNOS. FF pretreatment also improved EDV impaired by different concentrations of PA treatment. The dose- and time-dependent inhibition of cell proliferation by PA were inverted by FA pretreatment. Phosphorylation of eNOS and expression of ER stress related genes were all inverted by FA pretreatment in PA-treated MAEC. Our findings show that fenofibrate recovers damaged EDV by chronic HFD feeding and acute stimulation of PA, this effect is related with decreased ER stress and increased phosphorylation of eNOS. - Highlights: • Fenofibrate treatment improved pathological changes in thoracic aorta by chronic high-fat-diet feeding. • Fenofibrate pretreatment improved endothelium-dependent vasodilation impaired by different concentrations of palmitic acid. • The inhibition of proliferation in endothelial cells by palmitic acid were inverted by fenofibric

  4. Protective Effect of Boric Acid on Oxidative DNA Damage In Chinese Hamster Lung Fibroblast V79 Cell Lines

    PubMed Central

    Yılmaz, Sezen; Ustundag, Aylin; Cemiloglu Ulker, Ozge; Duydu, Yalcın

    2016-01-01

    Objective Many studies have been published on the antioxidative effects of boric acid (BA) and sodium borates in in vitro studies. However, the boron (B) concentrations tested in these in vitro studies have not been selected by taking into account the realistic blood B concentrations in humans due to the lack of comprehensive epidemiological studies. The recently published epidemiological studies on B exposure conducted in China and Turkey provided blood B concentrations for both humans in daily life and workers under extreme exposure conditions in occupational setting. The results of these studies have made it possible to test antioxidative effects of BA in in vitro studies within the concentra- tion range relevant to humans. The aim of this study was to investigate the protective ef- fects of BA against oxidative DNA damage in V79 (Chinese hamster lung fibroblast) cells. The concentrations of BA tested for its protective effect was selected by taking the blood B concentrations into account reported in previously published epidemiological studies. Therefore, the concentrations of BA tested in this study represent the exposure levels for humans in both daily life and occupational settings. Materials and Methods In this experimental study, comet assay and neutral red uptake (NRU) assay methods were used to determinacy to toxicity and genotoxicity of BA and hydrogen peroxide (H2O2). Results The results of the NRU assay showed that BA was not cytotoxic within the tested concentrations (3, 10, 30, 100 and 200 µM). These non-cytotoxic concentrations were used for comet assay. BA pre-treatment significantly reduced (P<0.05, one-way ANOVA) the DNA damaging capacity of H2O2 at each tested BA concentrations in V79 cells. Conclusion Consequently, pre-incubation of V79 cells with BA has significantly reduced the H2O2-induced oxidative DNA damage in V79 cells. The protective effect of BA against oxidative DNA damage in V79 cells at 5, 10, 50, 100 and 200 μM (54, 108, 540

  5. Protective Effect of Folic Acid on Oxidative DNA Damage: A Randomized, Double-Blind, and Placebo Controlled Clinical Trial.

    PubMed

    Guo, Xiaojuan; Cui, Huan; Zhang, Haiyang; Guan, Xiaoju; Zhang, Zheng; Jia, Chaonan; Wu, Jia; Yang, Hui; Qiu, Wenting; Zhang, Chuanwu; Yang, Zuopeng; Chen, Zhu; Mao, Guangyun

    2015-11-01

    Although previous reports have linked DNA damage with both transmissions across generations as well as our own survival, it is unknown how to reverse the lesion. Based on the data from a Randomized, Double-blind, Placebo Controlled Clinical Trial, this study aimed to assess the efficacy of folic acid supplementation (FAS) on DNA oxidative damage reversal.In this randomized clinical trial (RCT), a total of 450 participants were enrolled and randomly assigned to 3 groups to receive folic acid (FA) 0.4 mg/day (low-FA), 0.8 mg/day (high-FA), or placebo (control) for 8 weeks. The urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and creatinine (Cr) concentration at pre- and post-FAS were measured with modified enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC), respectively. A multivariate general linear model was applied to assess the individual effects of FAS and the joint effects between FAS and hypercholesterolemia on oxidative DNA damage improvement. This clinical trial was registered with ClinicalTrials.gov, number NCT02235948.Of the 438 subjects that received FA fortification or placebo, the median (first quartile, third quartile) of urinary 8-OHdG/Cr for placebo, low-FA, and high-FA groups were 58.19 (43.90, 82.26), 53.51 (38.97, 72.74), 54.73 (39.58, 76.63) ng/mg at baseline and 57.77 (44.35, 81.33), 51.73 (38.20, 71.30), and 50.65 (37.64, 76.17) ng/mg at the 56th day, respectively. A significant decrease of urinary 8-OHdG was observed after 56 days FA fortification (P < 0.001). Compared with the placebo, after adjusting for some potential confounding factors, including the baseline urinary 8-OHdG/Cr, the urinary 8-OHdG/Cr concentration significantly decreased after 56 days FAS [β (95% confidence interval) = -0.88 (-1.62, -0.14) and P = 0.020 for low-FA; and β (95% confidence interval) = -2.68 (-3.42, -1.94) and P < 0.001 for high-FA] in a dose-response fashion (Ptrend < 0.001). Test of

  6. Acid dew and the role of chemistry in the dry deposition of reactive gases to wetted surfaces

    NASA Technical Reports Server (NTRS)

    Chameides, William L.

    1987-01-01

    A formalism is developed to describe the dry deposition of soluble reactive gases to wetted surfaces in terms of the relevant meteorological conditions, the surface roughness, the total amount of liquid water present on the surface, the rate of accumulation of this water, and the species' solubility and reactivity in the surface water. This formulation is then incorporated into a model designed to simulate the generation of acidic dew from the deposition of HNO3, SO2, S(IV) oxidants, H2O2, and O3. Similar to the observations of dew in the continental U.S., the model generates a dewdrop pH of about 4 by the end of the night; the pH can rapidly fall to toxic levels due to rapid evaporation after sunrise. Relatively low deposition velocities are predicted for the SO2 and O3 because of their lower solubilities and hence larger surface resistances than those of the other oxidants. Because the chemical lifetime of the SO2 in the dew is influenced by the atmospheric levels of H2O2, O3, and SO2, the SO2 deposition velocity is a strong function of these species' atmospheric abundances.

  7. Involvement of Singlet Oxygen in 5-Aminolevulinic Acid-Induced Photodynamic Damage of Cucumber (Cucumis sativus L.) Chloroplasts 1

    PubMed Central

    Chakraborty, Niranjan; Tripathy, Baishnab Charan

    1992-01-01

    Cucumber (Cucumis sativus L., cv Poinsette) plants were sprayed with 20 millimolar 5-aminolevulinic acid and then incubated in the dark for 14 hours. The intact chloroplasts were isolated from the above plants in the dark and were exposed to weak light (250 micromoles per square meter per second). Within 30 minutes, photosystem II activity was reduced by 50%. The singlet oxygen (1O2) scavengers, histidine and sodium azide (NaN3) significantly protected against the damage caused to photosystem II. The hydroxyl radical scavenger formate failed to protect the thylakoid membranes. The production of 1O2 monitored as N,N-dimethyl p-nitrosoaniline bleaching increased as a function of light exposure time of treated chloroplasts and was abolished by the 1O2 quencher, NaN3. Membrane lipid peroxidation monitored as malondialdehyde production was also significantly reduced when chloroplasts were illuminated in the presence of NaN3 and histidine. Protochlorophyllide was the most abundant pigment accumulated in intact chloroplasts isolated from 5-aminolevulinic acid-treated plants and was probably acting as type II photosensitizer. PMID:16668650

  8. Protective effect of ω-3 polyunsaturated fatty acids on L-arginine-induced nephrotoxicity and oxidative damage in rat kidney.

    PubMed

    Khan, M W; Priyamvada, S; Khan, S A; Khan, S; Naqshbandi, A; Yusufi, A N K

    2012-10-01

    L-Arginine (ARG), an essential amino acid, is the endogenous source of the deleterious nitric oxide. Dietary ω-3 polyunsaturated fatty acid (PUFA)-enriched fish oil (FO) has been shown to reduce the severity of certain types of cancers, cardiovascular disease, and renal disease. Present study examined whether feeding of FO/flaxseed oil (FXO) would have protective effect against ARG-induced nephrotoxicity. ARG-induced nephrotoxicity was recorded by increased serum creatinine and blood urea nitrogen. ARG significantly altered the activities of metabolic and brush border membrane (BBM) enzymes. ARG caused significant imbalances in the antioxidant system. These alterations were associated with increased lipid peroxidation (LPO) and altered antioxidant enzyme activities. Feeding of FO and FXO with ARG ameliorated the changes in various parameters caused by ARG. Nephrotoxicity parameters lowered and enzyme activities of carbohydrate metabolism, BBM and inorganic phosphate (32Pi) transport were improved to near control values. ARG-induced LPO declined and antioxidant defense mechanism was strengthened by both FO and FXO alike. The results of the present study suggest that ω-3 PUFA-enriched FO and FXO from seafoods and plant sources, respectively, are similarly effective in reducing ARG-induced nephrotoxicity and oxidative damage. Thus, vegetarians who cannot consume FO can have similar health benefits from plant-derived ω-3 PUFA. PMID:22531969

  9. Trajectory analysis of acid deposition data from the new jersey pine barrens

    NASA Astrophysics Data System (ADS)

    Budd, William W.

    This research provides an example of the application of a simple method for evaluating regional interrelationships using air parcel trajectory analysis. An assessment of trajectories associated with storms affecting McDonald's Branch watershed (39°50'N, 74°30'W) is presented. A simple classification system is used to examine regional contributions of acid precursors. The results of the work suggest that major regional sources of acid precursor emissions dominated precipitation acidity for the Pine Barrens region from 1978 to 1981. An incremental approach to acid precipitation policy is suggested.

  10. First year sugar maple (Acer saccharum, Marsh. ) seedling nutrition, vesicular-arbuscular mycorrhizal colonization, physiology, and growth along an acidic deposition gradient in Michigan

    SciTech Connect

    McLaughlin, J.W.

    1992-01-01

    A field study was conducted to evaluate the use of foliar amino acid and root reducing sugar accumulations to separate acidic deposition from natural (i.e., soil phosphorus, mycorrhizae, and temperature) ecosystem stressors on first-year sugar maple seedling growth in three Michigan forests. Seedling growth was greatest at the sites exposed to highest levels of acidic deposition. However, sites receiving greatest acidic deposition rates also had high available soil phosphorus contents. No significant differences occurred, suggesting increased nitrogen loadings were not reflected in seedling tissue nitrogen. Seedling root or foliar calcium, magnesium, or potassium also were not significantly different, suggesting those elements were not growth limiting. Significant differences, however, occurred for seedling arginine and glutamine concentrations in foliage and reducing sugar concentrations in roots and were negatively correlated with seedling tissue phosphorus concentrations, suggesting phosphorus was limiting seedling growth at the low acidic deposition site. Vesicular-arbuscular mycorrhizal colonization of seedling roots was greater at the low acidic deposition site and positively correlated with seedling amino acid and reducing sugar accumulation but negatively correlated with sucrose concentrations in seedling roots, indicating that the fungal partner may have stimulated sucrose degradation to reducing sugars. Both air and soil temperatures were positively correlated with total sugar and sucrose concentrations in seedling roots. High levels of arginine, glutamine, and reducing sugars were negatively correlated with seedling growth indicating that seedlings at the low acidic deposition site were more stressed than seedlings at the sites receiving higher levels of pollutant loads. The results suggest differences in foliar arginine and glutamine and root reducing sugars in the forests in this study are likely due to natural rather than acidic deposition stress.

  11. Cell division in Escherichia coli BS-12 is hypersensitive to deoxyribonucleic acid damage by ultraviolet light.

    PubMed Central

    Bridges, B A; Mottershead, R P; Green, M H

    1977-01-01

    Escherichia coli BS-12 uvrA lon is hypersensitive to ultraviolet light. On minimal agar plates at densities in excess of about 10(7) bacteria per plate, as few as one or two photoreversible pyrimidine dimers in the entire genome are sufficient to cause inhibition of cell division. Most of the resulting filaments are unable to divide or form a viable colony. Inhibition of cell division appears to be a rapid consequence of replication of deoxyribonucleic acid containing a pyrimidine dimer. Photoreversibility of the inhibition of cell division persists indefinitely, indicating that the continued presence of the pyrimidine dimers (or the continued generation of daughter strand gaps) is necessary to maintain the division-inhibited state. In view of the kinetics for the production of filamentation by ultraviolet light and the extremely low average inducing fluence (0.03 J/m2), it is concluded that the initiating signal is not the same as that causing other inducible phenomena such as prophage induction or Weigle reactivation. PMID:400790

  12. Hyperspectral data for assessment of temporal changes in Norway spruce forest conditions in the mountainous region of the Czech Republic affected by long-term acidic deposition

    NASA Astrophysics Data System (ADS)

    Albrechtova, J.; Lhotakova, Z.; Misurec, J.; Kopackova, V.; Campbell, P. K. E.; Edwards-Jonasova, M.; Kupkova, L.; Cervena, L.; Potuckova, M.; Cudlin, P.

    2015-12-01

    The Ore Mts. located in the western part of the Czech Republic suffered during 1950's-1990´s heavy atmospheric pollution due to the mining activities and brown coal combustion. Acidic deposition in combination with harsh climatic conditions led there to large-scale forest decline. Although the load of SO2 has significantly decreased since 1991, tree damage was still visible in 1998 in terms of high defoliation or dead trees. Nowadays Norway spruce trees do not exhibit visible symptoms of damage but the full recovery of Norway spruce forests is not complete yet due to persisting adverse soil conditions. The temporal changes in the physiological status of Norway spruce forests in the Krušné Hory Mts. were evaluated using two sets of spectral images acquired in 1998 (ASAS) and in 2013 (APEX) and ground truth data (LAI, tree crown status, photosynthetic pigment contents, leaf spectral properties measured by spectroradiometer, soil properties - pH, contents of basic cations, heavy metals, etc.). Ground truth data were evaluated by unconstrained and constrained multivariate analyses using Canoco 5. The high resolution spectral images (ASAS and APEX) enabled the identification of a gradient of forest conditions and their comparison. In 1998 the stands exhibited different physiological status corresponding to the pollution gradient with healthier trees at the western part of the mountains. Analysis of the foliar chemistry in 2013 show a slight improvement of the Norway spruce physiological status in the eastern part of the mountains while the status of the western-located stands slightly worsened. In 2013 we also studied the differences in soil geochemical conditions, which appeared to be less favorable in the western part of the mountains characterized by a low base cation contents in the top organic horizon and a very low pH (pH<3).

  13. A Demonstration of Acid Rain and Lake Acidification: Wet Deposition of Sulfur Dioxide

    NASA Astrophysics Data System (ADS)

    Goss, Lisa M.

    2003-01-01

    A demonstration showing acid rain and lake acidification is described. In this demonstration, SO2 gas is generated in a large graduated cylinder and then dissolved in water droplets from a simple spray bottle. The droplets carry the acid into simulated lakes, one of which includes solid CaCO3 to mimic limestone's natural buffering capacity.

  14. Dry deposition of ammonia, nitric acid, ammonium, and nitrate to alpine tundra at Niwot Ridge, Colorado

    USGS Publications Warehouse

    Rattray, G.; Sievering, H.

    2001-01-01

    Micrometeorological measurements and ambient air samples, analyzed for concentrations of NH3, HNO3, NH4+, and NO3-, were collected at an alpine tundra site on Niwot Ridge, Colorado. The measured concentrations were extremely low and ranged between 5 and 70ngNm-3. Dry deposition fluxes of these atmospheric species were calculated using the micrometeorological gradient method. The calculated mean flux for NH3 indicates a net deposition to the surface and indicates that NH3 contributed significantly to the total N deposition to the tundra during the August-September measurement period. Our pre-measurement estimate of the compensation point for NH3 in air above the tundra was 100-200ngNm-3; thus, a net emission of NH3 was expected given the low ambient concentrations of NH3 observed. Based on our results, however, the NH3 compensation point at this alpine tundra site appears to have been at or below about 20ngNm-3. Large deposition velocities (>2cms-1) were determined for nitrate and ammonium and may result from reactions with surface-derived aerosols. Copyright (C) 2001 Elsevier Science B.V.Micrometeorological measurements and ambient air samples, analyzed for concentrations of NH3, HNO3, NH4+, and NO3-, were collected at an alpine tundra site on Niwot Ridge, Colorado. The measured concentrations were extremely low and ranged between 5 and 70 ng N m-3. Dry deposition fluxes of these atmospheric species were calculated using the micrometeorological gradient method. The calculated mean flux for NH3 indicates a net deposition to the surface and indicates that NH3 contributed significantly to the total N deposition to the tundra during the August-September measurement period. Our pre-measurement estimate of the compensation point for NH3 in air above the tundra was 100-200 ng N m-3; thus, a net emission of NH3 was expected given the low ambient concentrations of NH3 observed. Based on our results, however, the NH3 compensation point at this alpine tundra site appears to

  15. Mitochonic Acid 5 Binds Mitochondria and Ameliorates Renal Tubular and Cardiac Myocyte Damage.

    PubMed

    Suzuki, Takehiro; Yamaguchi, Hiroaki; Kikusato, Motoi; Hashizume, Osamu; Nagatoishi, Satoru; Matsuo, Akihiro; Sato, Takeya; Kudo, Tai; Matsuhashi, Tetsuro; Murayama, Kazutaka; Ohba, Yuki; Watanabe, Shun; Kanno, Shin-Ichiro; Minaki, Daichi; Saigusa, Daisuke; Shinbo, Hiroko; Mori, Nobuyoshi; Yuri, Akinori; Yokoro, Miyuki; Mishima, Eikan; Shima, Hisato; Akiyama, Yasutoshi; Takeuchi, Yoichi; Kikuchi, Koichi; Toyohara, Takafumi; Suzuki, Chitose; Ichimura, Takaharu; Anzai, Jun-Ichi; Kohzuki, Masahiro; Mano, Nariyasu; Kure, Shigeo; Yanagisawa, Teruyuki; Tomioka, Yoshihisa; Toyomizu, Masaaki; Tsumoto, Kohei; Nakada, Kazuto; Bonventre, Joseph V; Ito, Sadayoshi; Osaka, Hitoshi; Hayashi, Ken-Ichi; Abe, Takaaki

    2016-07-01

    Mitochondrial dysfunction causes increased oxidative stress and depletion of ATP, which are involved in the etiology of a variety of renal diseases, such as CKD, AKI, and steroid-resistant nephrotic syndrome. Antioxidant therapies are being investigated, but clinical outcomes have yet to be determined. Recently, we reported that a newly synthesized indole derivative, mitochonic acid 5 (MA-5), increases cellular ATP level and survival of fibroblasts from patients with mitochondrial disease. MA-5 modulates mitochondrial ATP synthesis independently of oxidative phosphorylation and the electron transport chain. Here, we further investigated the mechanism of action for MA-5. Administration of MA-5 to an ischemia-reperfusion injury model and a cisplatin-induced nephropathy model improved renal function. In in vitro bioenergetic studies, MA-5 facilitated ATP production and reduced the level of mitochondrial reactive oxygen species (ROS) without affecting activity of mitochondrial complexes I-IV. Additional assays revealed that MA-5 targets the mitochondrial protein mitofilin at the crista junction of the inner membrane. In Hep3B cells, overexpression of mitofilin increased the basal ATP level, and treatment with MA-5 amplified this effect. In a unique mitochondrial disease model (Mitomice with mitochondrial DNA deletion that mimics typical human mitochondrial disease phenotype), MA-5 improved the reduced cardiac and renal mitochondrial respiration and seemed to prolong survival, although statistical analysis of survival times could not be conducted. These results suggest that MA-5 functions in a manner differing from that of antioxidant therapy and could be a novel therapeutic drug for the treatment of cardiac and renal diseases associated with mitochondrial dysfunction. PMID:26609120

  16. Alleviation of salt-induced oxidative damage by 5-aminolevulinic acid in wheat seedlings

    NASA Astrophysics Data System (ADS)

    Genişel, Mucip; Erdal, Serkan

    2016-04-01

    The aim of this study was to elucidate how 5-aminolevulinic acid (ALA), the precursor of chlorophyll compounds, affects the defence mechanisms of wheat seedlings induced by salt stress. To determine the possible stimulative effects of ALA against salinity, 11-day old wheat seedlings were sprayed with ALA at two different concentrations (10 and 20 mg.l-1) and then stressed by exposure to salt (150 mM NaCl). The salt stress led to significant changes in the antioxidant activity. While guaiacol peroxidase activity decreased, the activities of superoxide dismutase, catalase, and ascorbate peroxidase markedly increased under salt stress. Compared to the salt stress alone, the application of ALA beforehand further increased the activity of these enzymes. This study is the first time the effects of ALA have been monitored with regard to protein content and the isoenzyme profiles of the antioxidant enzymes. Although the salt stress reduced both the soluble protein content and protein band intensities, pre-treating with ALA significantly mitigated these stress-induced reductions. The data for the isoenzyme profiles of the antioxidant enzymes paralleled that of the ALA-induced increases in antioxidant activity. As a consequence of the high antioxidant activity in the seedlings pre-treated with ALA, the stress-induced elevations in the reactive oxygen species, superoxide anion, and hydrogen peroxide contents and lipid peroxidation levels were markedly diminished. Taken together, this data demonstrated that pre-treating with ALA confers resistance to salt stress by modulating the protein synthesis and antioxidant activity in wheat seedlings.

  17. Deposition and rainwater concentrations of trifluoroacetic acid in the United States from the use of HFO-1234yf

    NASA Astrophysics Data System (ADS)

    Kazil, J.; McKeen, S.; Kim, S.-W.; Ahmadov, R.; Grell, G. A.; Talukdar, R. K.; Ravishankara, A. R.

    2014-12-01

    Currently, HFC-134a (1,1,1,2-tetrafluoroethane) is the most common refrigerant in automobile air conditioners. This high global warming potential substance (100 year GWP of 1370) will likely be phased out and replaced with HFO-1234yf (2,3,3,3-tetrafluoropropene) that has a 100 year GWP of 4. HFO-1234yf will be oxidized to produce trifluoroacetic acid (TFA) in clouds. TFA, a mildly toxic substance with detrimental effects on some aquatic organisms at high concentrations (≥100μgL-1), would be transported by rain to the surface and enter bodies of water. We investigated the dry and wet deposition of TFA from HFO-1234yf over the contiguous USA using the Advanced Research Weather Research and Forecasting model (ARW) with interactive chemical, aerosol, and cloud processes (WRF/Chem) model. Special focus was placed on emissions from three continental USA regions with different meteorological characteristics. WRF/Chem simulated meteorology, cloud processes, gas and aqueous phase chemistry, and dry and wet deposition between May and September 2006. The model reproduced well the multimonth total sulfate wet deposition (4% bias) and its spatial variability (r = 0.86) observed by the National Atmospheric Deposition Program. HFO-1234yf emissions were obtained by assuming the number of automobile air conditioners to remain unchanged, and substituting HFO-1234yf, mole-per-mole for HFC-134a. Our estimates of current HFC-134a emissions were in agreement with field data. Average TFA rainwater concentration was 0.89μgL-1, with peak values of 7.8μgL-1, for the May-September 2006 period over the contiguous USA. TFA rainwater concentrations over the dry western USA were often significantly higher, but wet-deposited TFA amounts remained relatively low at such locations.

  18. No effect of short-term amino acid supplementation on variables related to skeletal muscle damage in 100 km ultra-runners - a randomized controlled trial

    PubMed Central

    2011-01-01

    Background The purpose of this study was to investigate the effect of short-term supplementation of amino acids before and during a 100 km ultra-marathon on variables of skeletal muscle damage and muscle soreness. We hypothesized that the supplementation of amino acids before and during an ultra-marathon would lead to a reduction in the variables of skeletal muscle damage, a decrease in muscle soreness and an improved performance. Methods Twenty-eight experienced male ultra-runners were divided into two groups, one with amino acid supplementation and the other as a control group. The amino acid group was supplemented a total of 52.5 g of an amino acid concentrate before and during the 100 km ultra-marathon. Pre- and post-race, creatine kinase, urea and myoglobin were determined. At the same time, the athletes were asked for subjective feelings of muscle soreness. Results Race time was not different between the groups when controlled for personal best time in a 100 km ultra-marathon. The increases in creatine kinase, urea and myoglobin were not different in both groups. Subjective feelings of skeletal muscle soreness were not different between the groups. Conclusions We concluded that short-term supplementation of amino acids before and during a 100 km ultra-marathon had no effect on variables of skeletal muscle damage and muscle soreness. PMID:21473783

  19. Field and airborne spectral characterization of suspected damage in red spruce (picea rubens) from Vermont

    NASA Technical Reports Server (NTRS)

    Rock, B. N.; Vogelmann, J. E.; Williams, D. L.

    1985-01-01

    The utilization of remote sensing to monitor forest damage due to acid deposition is investigated. Spectral and water measurements and aircraft radiance data of red spruce and balsam fir, collected in Camels Hump Mountain and Ripton, Vermont between August 13-20, 1984, are analyzed to evaluate the damage levels of the trees. Variations in reflectance features and canopy moisture content are studied. It is observed that damage correlates with elevation (greater damage at higher elevations); xylem water column tension is greater at higher damage sites; and a 'blue shift' is indicated in the spectral data at high damage sites.

  20. REGIONAL AIR QUALITY AND ACID DEPOSITION MODELING AND THE ROLE FOR VISUALIZATION

    EPA Science Inventory

    The U.S Environmental Protection Agency (EPA) uses air quality and deposition models to advance the scientific understanding of basic physical and chemical processes related to air pollution, and to assess the effectiveness of alternative emissions control strategies. his paper p...

  1. Effects of paracetamol and propacetamol on gastric mucosal damage and gastric lipid peroxidation caused by acetylsalicylic acid (ASA) in rats.

    PubMed

    Galunska, B; Marazova, K; Tankova, T; Popov, A; Frangov, P; Krushkov, I; Di Massa, A

    2002-08-01

    We have studied the effect of paracetamol and its pro-drug propacetamol on gastric mucosal damage induced by acetylsalicylic acid (ASA) and its possible relation to changes in gastric lipid peroxidation status in rats. Paracetamol or propacetamol were administered intragastrically 1h before ASA (300 mg kg(-1)) in the following equivalent doses: 62.5, 125.0 and 250.0 mg kg(-1) or 125.0, 250.0 and 500.0 mg kg(-1), respectively. The effects of the tested agents were compared to that of prostaglandin E2 (PGE2) 15, 30 and 60 mg kg(-1). Gastric ulcer formation was estimated morphometrically 4h after ASA administration. Malondialdehyde (MDA), glutathione (reduced, GSH, and oxidized, GSSG) and uric acid (UA) were determined in gastric mucosa and blood plasma and used as biochemical markers of the oxidative status. The results showed that paracetamol (250, 125, 62.5 mg kg(-1)) and propacetamol (500, 250, 125 mg kg(-1)) diminished the area of ASA-induced gastric lesions. The effect of propacetamol was more pronounced than that of paracetamol and similar to that of PGE2. Gastric MDA increased 3-fold in the ASA-group. The tested agents reduced it by a range of 30-70%. In all pretreated groups gastric glutathione and UA levels were found higher than that of control group and lower than that of ASA-group. Paracetamol and propacetamol, as well as PGE2, diminished the lipid peroxidation in plasma to a lesser extent than in gastric mucosa, but maintained elevated levels of the selective plasma antioxidant UA. These results show that the ASA-induced gastric mucosal damage is accompanied by the development of oxidative stress, evidenced by the accumulation of MDA, and concomitant initial activation of cell antioxidant defences. As paracetamol and propacetamol tend to decrease gastric lesions caused by ASA and alter gastric mucosal MDA, glutathione and UA values in a favorable manner, it could be suggested that their effects on the gastric mucosa could be related to interference with

  2. Skeletal Muscle Lipid Deposition and Insulin Resistance: Impact of Dietary Fatty Acids and Exercise

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evidence has mounted indicating that elevated intramuscular triacylglycerol levels are associated with diminished insulin sensitivity in skeletal muscle. This lipid accumulation is most likely due to enhanced fatty acid uptake into the muscle coupled with diminished mitochondrial lipid oxidation. Th...

  3. Bile acids in combination with low pH induce oxidative stress and oxidative DNA damage: relevance to the pathogenesis of Barrett's oesophagus

    PubMed Central

    Dvorak, Katerina; Payne, Claire M; Chavarria, Melissa; Ramsey, Lois; Dvorakova, Barbora; Bernstein, Harris; Holubec, Hana; Sampliner, Richard E; Guy, Naihsuan; Condon, Amanda; Bernstein, Carol; Green, Sylvan B; Prasad, Anil; Garewal, Harinder S

    2007-01-01

    Background Barrett's oesophagus is a premalignant condition associated with an increased risk for the development of oesophageal adenocarcinoma (ADCA). Previous studies indicated that oxidative damage contributes to the development of ADCA. Objective To test the hypothesis that bile acids and gastric acid, two components of refluxate, can induce oxidative stress and oxidative DNA damage. Methods Oxidative stress was evaluated by staining Barrett's oesophagus tissues with different degrees of dysplasia with 8‐hydroxy‐deoxyguanosine (8‐OH‐dG) antibody. The levels of 8‐OH‐dG were also evaluated ex vivo in Barrett's oesophagus tissues incubated for 10 min with control medium and medium acidified to pH 4 and supplemented with 0.5 mM bile acid cocktail. Furthermore, three oesophageal cell lines (Seg‐1 cells, Barrett's oesophagus cells and HET‐1A cells) were exposed to control media, media containing 0.1 mM bile acid cocktail, media acidified to pH 4, and media at pH 4 supplemented with 0.1 mM bile acid cocktail, and evaluated for induction of reactive oxygen species (ROS). Results Immunohistochemical analysis showed that 8‐OH‐dG is formed mainly in the epithelial cells in dysplastic Barrett's oesophagus. Importantly, incubation of Barrett's oesophagus tissues with the combination of bile acid cocktail and acid leads to increased formation of 8‐OH‐dG. An increase in ROS in oesophageal cells was detected after exposure to pH 4 and bile acid cocktail. Conclusions Oxidative stress and oxidative DNA damage can be induced in oesophageal tissues and cells by short exposures to bile acids and low pH. These alterations may underlie the development of Barrett's oesophagus and tumour progression. PMID:17145738

  4. Melatonin is more effective than ascorbic acid and β-carotene in improvement of gastric mucosal damage induced by intensive stress

    PubMed Central

    Akinci, Aysin; Cetin, Asli; Ates, Burhan

    2015-01-01

    Introduction Oxidative stress has been considered to play a primary role in the pathogenesis of stress-induced gastric damage. The aim of this study was to investigate the effects of melatonin, ascorbic acid and β-carotene on stress-induced gastric mucosal damage. Material and methods Fifty-six male Wistar albino rats were divided into control, stress, stress + standard diet, stress + saline, stress + melatonin, stress + ascorbic acid and stress + β-carotene groups. The rats from stress groups were exposed to starvation, immobilization and cold by immobilizing for 8 h at +4°C following 72-hour food restriction. Following stress application, melatonin, ascorbic acid and β-carotene were administered for 7 days. Specimens of gastric tissue were prepared for microscopic and biochemical examinations. Results Mean histopathological damage scores and mean tissue malondialdehyde levels were significantly decreased but mean tissue glutathione levels and glutathione peroxidase and superoxide dismutase activities were increased in treatment groups vs. stress groups in general. Mean histopathological damage scores of the stress + Mel group was lower than those of stress + D, stress + S, stress + β-car (p < 0.05) and stress + Asc groups (p < 0.005). Additionally, mean tissue catalase activity of the stress + Mel group was higher than that of stress + S (p < 0.005), stress + D (p < 0.05) and stress + β-car groups (p < 0.05). Conclusions Melatonin is more effective than ascorbic acid and β-carotene in improvement of gastric damage induced by intensive stress. We suggest that as well as the direct antioxidant and free radical scavenging potency of melatonin, its indirect effect via the brain-gut axis might account for its greater beneficial action against stress-induced gastric damage. PMID:26528359

  5. The Effect of Slaughter Season on the Fatty Acid Profile in Four Types of Fat Deposits in Crossbred Beef Bulls

    PubMed Central

    Sobczuk-Szul, Monika; Wroński, Marek; Wielgosz-Groth, Zofia; Mochol, Magdalena; Rzemieniewski, Arkadiusz; Nogalski, Zenon; Pogorzelska-Przybyłek, Paulina; Purwin, Cezary

    2013-01-01

    The objective of this study was to determine the effect of slaughter season on the fatty acid profile in four types of fat deposits in crossbred (Polish Holstein Friesian Black-and-White×Limousine) beef bulls. The percentage share of fatty acids was determined by gas chromatography and were divided into the following categories of fatty acids: saturated (SFAs), unsaturated (UFAs), monounsaturated (MUFAs), polyunsaturated (PUFAs), desirable hypocholesterolemic (DFAs) and undesirable hypercholesterolemic (OFAs), n-3 and n-6. Perinephric fat was characterized by the highest SFA concentrations (59.89%), and subcutaneous fat had the highest MUFA content (50.63%). Intramuscular fat was marked by a high percentage share of PUFAs and the highest PUFA/SFA ratio. The slaughter season had a significant effect on the levels of C18:3, C20:4 (p≤0.01) and conjugated linoleic acid (p≤0.05). There was an interaction between the slaughter season and fat type for the content of C20:4 (p≤0.01) and C20:5 (p≤0.05). The results of this study show that beef from cattle slaughtered in the summer season has a higher nutritional value and more health-promoting properties. PMID:25049787

  6. Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

    NASA Astrophysics Data System (ADS)

    Provine, J.; Schindler, Peter; Kim, Yongmin; Walch, Steve P.; Kim, Hyo Jin; Kim, Ki-Hyun; Prinz, Fritz B.

    2016-06-01

    The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiNx), particularly for use a low k dielectric spacer. One of the key material properties needed for SiNx films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiNx and evaluate the film's WER in 100:1 dilutions of HF in H2O. The remote plasma capability available in PEALD, enabled controlling the density of the SiNx film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiNx of 6.1 Å/min, which is similar to WER of SiNx from LPCVD reactions at 850 °C.

  7. Insights from the metagenome of an acid salt lake: the role of biology in an extreme depositional environment.

    PubMed

    Johnson, Sarah Stewart; Chevrette, Marc Gerard; Ehlmann, Bethany L; Benison, Kathleen Counter

    2015-01-01

    The extremely acidic brine lakes of the Yilgarn Craton of Western Australia are home to some of the most biologically challenging waters on Earth. In this study, we employed metagenomic shotgun sequencing to generate a microbial profile of the depositional environment associated with the sulfur-rich sediments of one such lake. Of the 1.5 M high-quality reads generated, 0.25 M were mapped to protein features, which in turn provide new insights into the metabolic function of this community. In particular, 45 diverse genes associated with sulfur metabolism were identified, the majority of which were linked to either the conversion of sulfate to adenylylsulfate and the subsequent production of sulfide from sulfite or the oxidation of sulfide, elemental sulfur, and thiosulfate via the sulfur oxidation (Sox) system. This is the first metagenomic study of an acidic, hypersaline depositional environment, and we present evidence for a surprisingly high level of microbial diversity. Our findings also illuminate the possibility that we may be meaningfully underestimating the effects of biology on the chemistry of these sulfur-rich sediments, thereby influencing our understanding of past geobiological conditions that may have been present on Earth as well as early Mars. PMID:25923206

  8. Soil nutrient bioavailability and nutrient content of pine trees (Pinus thunbergii) in areas impacted by acid deposition in Korea.

    PubMed

    Yang, Jae E; Lee, Wi-Young; Ok, Yong Sik; Skousen, Jeffrey

    2009-10-01

    Acid deposition has caused detrimental effects on tree growth near industrial areas of the world. Preliminary work has indicated that concentrations of NO(3-), SO(4)(2-), F( - ) and Al in soil solutions were 2 to 33 times higher in industrial areas compared to non-industrial areas in Korea. This study evaluated soil nutrient bioavailability and nutrient contents of red pine (Pinus thunbergii) needles in forest soils of industrial and non-industrial areas of Korea. Results confirm that forest soils of industrial areas have been acidified mainly by deposition of sulfate, resulting in increases of Al, Fe and Mn and decreases of Ca, Mg and K concentrations in soils and soil solutions. In soils of industrial areas, the molar ratios of Ca/Al and Mg/Al in forest soils were <2, which can lead to lower levels and availability of nutrients for tree growth. The Ca/Al molar ratio of Pinus thunbergii needles on non-industrial sites was 15, while that of industrial areas was 10. Magnesium concentrations in needles of Pinus thunbergii were lower in soils of industrial areas and the high levels of acid cations such as Al and Mn in these soils may have antagonized the uptake of base cations like Mg. Continued acidification can further reduce uptake of base cations by trees. Results show that Mg deficiency and high concentrations of Al and Mn in soil solution can be limiting factors for Pinus thunbergii growth in industrial areas of Korea. PMID:18758977

  9. Insights from the Metagenome of an Acid Salt Lake: The Role of Biology in an Extreme Depositional Environment

    PubMed Central

    Johnson, Sarah Stewart; Chevrette, Marc Gerard; Ehlmann, Bethany L.; Benison, Kathleen Counter

    2015-01-01

    The extremely acidic brine lakes of the Yilgarn Craton of Western Australia are home to some of the most biologically challenging waters on Earth. In this study, we employed metagenomic shotgun sequencing to generate a microbial profile of the depositional environment associated with the sulfur-rich sediments of one such lake. Of the 1.5 M high-quality reads generated, 0.25 M were mapped to protein features, which in turn provide new insights into the metabolic function of this community. In particular, 45 diverse genes associated with sulfur metabolism were identified, the majority of which were linked to either the conversion of sulfate to adenylylsulfate and the subsequent production of sulfide from sulfite or the oxidation of sulfide, elemental sulfur, and thiosulfate via the sulfur oxidation (Sox) system. This is the first metagenomic study of an acidic, hypersaline depositional environment, and we present evidence for a surprisingly high level of microbial diversity. Our findings also illuminate the possibility that we may be meaningfully underestimating the effects of biology on the chemistry of these sulfur-rich sediments, thereby influencing our understanding of past geobiological conditions that may have been present on Earth as well as early Mars. PMID:25923206

  10. Deposition of Lignin Droplets Produced During Dilute Acid Pretreatment of Maize Stems Retards Enzymatic Hydrolysis of Cellulose

    SciTech Connect

    Selig, M. J.; Viamajala, S.; Decker, S. R.; Tucker, M. P.; Himmel, M. E.; Vinzant, T. B.

    2007-01-01

    Electron microscopy of lignocellulosic biomass following high-temperature pretreatment revealed the presence of spherical formations on the surface of the residual biomass. The hypothesis that these droplet formations are composed of lignins and possible lignin carbohydrate complexes is being explored. Experiments were conducted to better understand the formation of these lignin droplets and the possible implications they might have on the enzymatic saccharification of pretreated biomass. It was demonstrated that these droplets are produced from corn stover during pretreatment under neutral and acidic pH at and above 130C, and that they can deposit back onto the surface of residual biomass. The deposition of droplets produced under certain pretreatment conditions (acidic pH; T > 150C) and captured onto pure cellulose was shown to have a negative effect (5-20%) on the enzymatic saccharification of this substrate. It was noted that droplet density (per unit area) was greater and droplet size more variable under conditions where the greatest impact on enzymatic cellulose conversion was observed. These results indicate that this phenomenon has the potential to adversely affect the efficiency of enzymatic conversion in a lignocellulosic biorefinery.

  11. Preparation and evaluation of SiO2-deposited stearic acid-g-chitosan nanoparticles for doxorubicin delivery

    PubMed Central

    Yuan, Hong; Bao, Xin; Du, Yong-Zhong; You, Jian; Hu, Fu-Qiang

    2012-01-01

    Purpose: Both polymer micelles and mesoporous silica nanoparticles have been widely researched as vectors for small molecular insoluble drugs. To combine the advantages of copolymers and silica, studies on the preparation of copolymer-silica composites and cellular evaluation were carried out. Methods: First, a stearic acid-g-chitosan (CS-SA) copolymer was synthesized through a coupling reaction, and then silicone oxide (SiO2)-deposited doxorubicin (DOX)-loaded stearic acid-g-chitosan (CS-SA/SiO2/DOX) nanoparticles were prepared through the sol-gel reaction. Physical and chemical properties such as particle size, zeta potential, and morphologies were examined, and small-angle X-ray scattering (SAXS) analysis was employed to identify the mesoporous structures of the generated nanoparticles. Cellular uptake and cytotoxicity studies were also conducted. Results: CS-SA/SiO2/DOX nanoparticles with different amounts of SiO2 deposited were obtained, and SAXS studies showed that mesoporous structures existed in the CS-SA/SiO2/DOX nanoparticles. The mesoporous size of middle-ratio and high-ratio deposited CS-SA/SiO2/DOX nanoparticles were 4–5 nm and 8–10 nm, respectively. Based on transmission electron microscopy images of CS-SA/SiO2/DOX nanoparticles, dark rings around the nanoparticles could be observed in contrast with CS-SA/DOX micelles. Furthermore, CS-SA/SiO2/DOX nanoparticles exhibited faster release behavior in vitro than CS-SA/DOX micelles; cellular uptake research in A549 indicated that the CS-SA/SiO2/DOX nanoparticles were taken up by A549 cells more rapidly, and that CS-SA/SiO2/DOX nanoparticles entered the cell more easily when the amount of SiO2 was higher. IC50 values of CS-SA/DOX micelles, CS-SA/SiO2/DOX-4, CS-SA/SiO2/DOX-8, and CS-SA/SiO2/DOX-16 nanoparticles against A549 cells measured using the MTT assay were 1.69, 0.93, 0.32, and 0.12 μg/mL, respectively. Conclusion: SiO2-deposited stearic acid-g-chitosan organic–inorganic composites show promise

  12. Exogenous 5-Aminolevulenic Acid Promotes Seed Germination in Elymus nutans against Oxidative Damage Induced by Cold Stress

    PubMed Central

    Fu, Juanjuan; Sun, Yongfang; Chu, Xitong; Xu, Yuefei; Hu, Tianming

    2014-01-01

    The protective effects of 5-aminolevulenic acid (ALA) on germination of Elymus nutans Griseb. seeds under cold stress were investigated. Seeds of E. nutans (Damxung, DX and Zhengdao, ZD) were pre-soaked with various concentrations (0, 0.1, 0.5, 1, 5, 10 and 25 mg l−1) of ALA for 24 h before germination under cold stress (5°C). Seeds of ZD were more susceptible to cold stress than DX seeds. Both seeds treated with ALA at low concentrations (0.1–1 mg l−1) had higher final germination percentage (FGP) and dry weight at 5°C than non-ALA-treated seeds, whereas exposure to higher ALA concentrations (5–25 mg l−1) brought about a dose dependent decrease. The highest FGP and dry weight of germinating seeds were obtained from seeds pre-soaked with 1 mg l−1 ALA. After 5 d of cold stress, pretreatment with ALA provided significant protection against cold stress in the germinating seeds, significantly enhancing seed respiration rate and ATP synthesis. ALA pre-treatment also increased reduced glutathione (GSH), ascorbic acid (AsA), total glutathione, and total ascorbate concentrations, and the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), whereas decreased the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2), and superoxide radical (O2•−) release in both germinating seeds under cold stress. In addition, application of ALA increased H+-ATPase activity and endogenous ALA concentration compared with cold stress alone. Results indicate that ALA considered as an endogenous plant growth regulator could effectively protect E. nutans seeds from cold-induced oxidative damage during germination without any adverse effect. PMID:25207651

  13. Exogenous 5-aminolevulenic acid promotes seed germination in Elymus nutans against oxidative damage induced by cold stress.

    PubMed

    Fu, Juanjuan; Sun, Yongfang; Chu, Xitong; Xu, Yuefei; Hu, Tianming

    2014-01-01

    The protective effects of 5-aminolevulenic acid (ALA) on germination of Elymus nutans Griseb. seeds under cold stress were investigated. Seeds of E. nutans (Damxung, DX and Zhengdao, ZD) were pre-soaked with various concentrations (0, 0.1, 0.5, 1, 5, 10 and 25 mg l(-1)) of ALA for 24 h before germination under cold stress (5°C). Seeds of ZD were more susceptible to cold stress than DX seeds. Both seeds treated with ALA at low concentrations (0.1-1 mg l(-1)) had higher final germination percentage (FGP) and dry weight at 5°C than non-ALA-treated seeds, whereas exposure to higher ALA concentrations (5-25 mg l(-1)) brought about a dose dependent decrease. The highest FGP and dry weight of germinating seeds were obtained from seeds pre-soaked with 1 mg l(-1) ALA. After 5 d of cold stress, pretreatment with ALA provided significant protection against cold stress in the germinating seeds, significantly enhancing seed respiration rate and ATP synthesis. ALA pre-treatment also increased reduced glutathione (GSH), ascorbic acid (AsA), total glutathione, and total ascorbate concentrations, and the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), whereas decreased the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2), and superoxide radical (O2•-) release in both germinating seeds under cold stress. In addition, application of ALA increased H+-ATPase activity and endogenous ALA concentration compared with cold stress alone. Results indicate that ALA considered as an endogenous plant growth regulator could effectively protect E. nutans seeds from cold-induced oxidative damage during germination without any adverse effect. PMID:25207651

  14. A nitrilo-tri-acetic-acid/acetic acid route for the deposition of epitaxial cerium oxide films as high temperature superconductor buffer layers

    SciTech Connect

    Thuy, T.T.; Lommens, P.; Narayanan, V.; Van de Velde, N.; De Buysser, K.; Herman, G.G.; Cloet, V.; Van Driessche, I.

    2010-09-15

    A water based cerium oxide precursor solution using nitrilo-tri-acetic-acid (NTA) and acetic acid as complexing agents is described in detail. This precursor solution is used for the deposition of epitaxial CeO{sub 2} layers on Ni-5at%W substrates by dip-coating. The influence of the complexation behavior on the formation of transparent, homogeneous solutions and gels has been studied. It is found that ethylenediamine plays an important role in the gelification. The growth conditions for cerium oxide films were Ar-5% gas processing atmosphere, a solution concentration level of 0.25 M, a dwell time of 60 min at 900 {sup o}C and 5-30 min at 1050 {sup o}C. X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM), pole figures and spectroscopic ellipsometry were used to characterize the CeO{sub 2} films with different thicknesses. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) was used to determine the carbon residue level in the surface of the cerium oxide film, which was found to be lower than 0.01%. Textured films with a thickness of 50 nm were obtained. - Graphical abstract: Study of the complexation and hydrolysis behavior of Ce{sup 4+} ions in the presence of nitrilo-tri-acetic acid and the subsequent development of an aqueous chemical solution deposition route suited for the processing of textured CeO{sub 2} buffer layers on Ni-W tapes.

  15. Iron deposition as acidic groundwater encounters carbonates in the alluvium of Pinal Creek, Arizona, U.S.A.

    USGS Publications Warehouse

    Lind, Carol J.; Oscarson, R.L.

    1997-01-01

    In a column experiment, acidic groundwater from Pinal Creek Arizona, a Cu mining area, was eluted through a composited alluvial sample obtained from a core that had been removed from a well downgradient of the acidic groundwater. The minerals present in typical grains and flakes in the alluvium before and after the elution were determined by X-ray diffraction (XRD), scanning electron microscopy, and energy dispersive multichannel analyses (EDX). The concentrations of Fe, Ti, Mn, Si, Al, Na, Ca, K, Mg and S in these grains and flakes and in their microcrystalline surface coatings were measured by EDX. In addition to magnetite, hematite, and Fe-Ti oxides, Fe was most concentrated in micas (especially biotite-like flakes) and in the microcrystalline coatings. The measured elements in these microcrystalline coatings were primarily K, Fe, Al, and Si. The microcrystalline coatings on the mica flakes also contained Mg. The approximate 1:3 Mg:Si atomic ratios (ARs) of the biotite-like flakes both before and after the elution would suggest that the Fe deposited during the elution had not substituted for Mg in these flakes. As a result of the elution, assuming no loss of Si, the averaged recorded Fe:Si AR of the microcrystalline coatings increased from (0,46 to 0.58):3.00. Iron deposition on the typical grains and flakes may relate to the presence of Fe in the particle on which it is deposited or to the presence of Fe in the microcrystalline surface coatings before elution. The data here are not sufficient for a statistical evaluation, but elution caused the following trends: (1) The Fe:Si A R increased in the (K,Fe,Al,Si)-microcrystalline surface coatings; (2) For the mica flakes, there was more than a 2-fold increase in the Fe:Si AR for the microcrystalline surface coatings of the Fe-rich biotite-like flakes but no measurable increase of the Fe:Si AR for the microcrystalline surface coatings of the muscovite-like flakes that contained 3-5 times less Fe; (3) Also for the

  16. Formation of Acid Mine Drainage Water at Sb (Au) Deposit Pezinok

    NASA Astrophysics Data System (ADS)

    Rusko, Miroslav; Andráš, Peter; Kušnierová, Mária; Aschenbrenner, Štefan; Krnáč, Jozef; Dubiel, Ján

    2011-01-01

    The article presents the results of leaching experiments regarding the comparison of chemical and biological-chemical leaching of ores from the Sb-(Au-) base metal deposit Pezinok (Malé Karpaty., the Western Carpathians) under the same conditions in solution. Discussed are the differences between chemical and biological-chemical leaching activity. The extent and the kinetics of the biological-chemical leaching of the technogenous sediments from the setting-pits are significantly higher than those without bacteria.

  17. The importance of acid digestion of urine prior to spontaneous deposition of 210Po.

    PubMed

    Fellman, A; Ralston, L; Hickman, D; Ayres, L; Cohen, N; Spitz, H; Robinson, B

    1989-10-01

    Historically, radiochemical analysis of 210Po in urine has used spontaneous deposition of the nuclide directly from raw urine onto a suitable metal disc. Consequently, the urinary excretion fraction for Po in some current metabolic and dosimetric models is based on studies which inherently assume that metabolized (i.e., filtered out of the blood by the kidneys) 210Po is plated with the same efficiency as tracer 210Po which has been added to urine samples. Urine samples collected after intravenous administration of 210Po citrate to two species of nonhuman primates were divided and simultaneously analyzed via two methods: the historical procedure of plating 210Po from raw urine for one sample and a method which includes the addition of 208Po tracer and sample digestion with concentrated HNO3 prior to 210Po deposition for the other sample. A more significant amount of 210Po was consistently recovered when the urine was wet ashed then when it was not wet ashed. A temporal relationship was found to describe the change in the ratio of the deposition recoveries for the two methods. Possible mechanisms for this phenomenon and its dosimetric implications are discussed. PMID:2507478

  18. Biomimetic Deposition of Hydroxyapatite by Mixed Acid Treatment of Titanium Surfaces.

    PubMed

    Zhao, J M; Park, W U; Hwang, K H; Lee, J K; Yoon, S Y

    2015-03-01

    A simple chemical method was established for inducing bioactivity of Ti metal. In the present study, two kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coatings successfully formed on the Ti surfaces in the simulated body fluid. Strong mixed acid etching was used to increase the roughness of the metal surface, because the porous and rough surfaces allow better adhesion between Ca-P coatings and substrate. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Some specimens were treated with a 5 M NaOH aqueous solution, and then heat treated at 600 °C in order to form an amorphous sodium titanate layer on their surface. This treated titanium metal is believed to form a dense and uniform bone-like apatite layer on its surface in a simulated body fluid (SBF). This study proved that mixed acid treatment is not only important for surface passivation but is also another bioactive treatment for titanium surfaces, an alternative to alkali treatment. In addition, mixed acid treatment uses a lower temperature and shorter time period than alkali treatment. PMID:26413704

  19. Suppression of fat deposition in broiler chickens by (-)-hydroxycitric acid supplementation: A proteomics perspective

    PubMed Central

    Peng, Mengling; Han, Jing; Li, Longlong; Ma, Haitian

    2016-01-01

    (-)-Hydroxycitric acid (HCA) suppresses fatty acid synthesis in animals, but its biochemical mechanism in poultry is unclear. This study identified the key proteins associated with fat metabolism and elucidated the biochemical mechanism of (-)-HCA in broiler chickens. Four groups (n = 30 each) received a diet supplemented with 0, 1000, 2000 or 3000 mg/kg (-)-HCA for 4 weeks. Of the differentially expressed liver proteins, 40 and 26 were identified in the mitochondrial and cytoplasm respectively. Pyruvate dehydrogenase E1 components (PDHA1 and PDHB), dihydrolipoyl dehydrogenase (DLD), aconitase (ACO2), a-ketoglutarate dehydrogenase complex (DLST), enoyl-CoA hydratase (ECHS1) and phosphoglycerate kinase (PGK) were upregulated, while NADP-dependent malic enzyme (ME1) was downregulated. Biological network analysis showed that the identified proteins were involved in glycometabolism and lipid metabolism, whereas PDHA1, PDHB, ECHS1, and ME1 were identified in the canonical pathway by Ingenuity Pathway Analysis. The data indicated that (-)-HCA inhibited fatty acid synthesis by reducing the acetyl-CoA supply, via promotion of the tricarboxylic acid cycle (upregulation of PDHA1, PDHB, ACO2, and DLST expression) and inhibition of ME1 expression. Moreover, (-)-HCA promoted fatty acid beta-oxidation by upregulating ECHS1 expression. These results reflect a biochemically relevant mechanism of fat reduction by (-)-HCA in broiler chickens. PMID:27586962

  20. Suppression of fat deposition in broiler chickens by (-)-hydroxycitric acid supplementation: A proteomics perspective.

    PubMed

    Peng, Mengling; Han, Jing; Li, Longlong; Ma, Haitian

    2016-01-01

    (-)-Hydroxycitric acid (HCA) suppresses fatty acid synthesis in animals, but its biochemical mechanism in poultry is unclear. This study identified the key proteins associated with fat metabolism and elucidated the biochemical mechanism of (-)-HCA in broiler chickens. Four groups (n = 30 each) received a diet supplemented with 0, 1000, 2000 or 3000 mg/kg (-)-HCA for 4 weeks. Of the differentially expressed liver proteins, 40 and 26 were identified in the mitochondrial and cytoplasm respectively. Pyruvate dehydrogenase E1 components (PDHA1 and PDHB), dihydrolipoyl dehydrogenase (DLD), aconitase (ACO2), a-ketoglutarate dehydrogenase complex (DLST), enoyl-CoA hydratase (ECHS1) and phosphoglycerate kinase (PGK) were upregulated, while NADP-dependent malic enzyme (ME1) was downregulated. Biological network analysis showed that the identified proteins were involved in glycometabolism and lipid metabolism, whereas PDHA1, PDHB, ECHS1, and ME1 were identified in the canonical pathway by Ingenuity Pathway Analysis. The data indicated that (-)-HCA inhibited fatty acid synthesis by reducing the acetyl-CoA supply, via promotion of the tricarboxylic acid cycle (upregulation of PDHA1, PDHB, ACO2, and DLST expression) and inhibition of ME1 expression. Moreover, (-)-HCA promoted fatty acid beta-oxidation by upregulating ECHS1 expression. These results reflect a biochemically relevant mechanism of fat reduction by (-)-HCA in broiler chickens. PMID:27586962

  1. Ammonia-induced oxidative damage in neurons is prevented by resveratrol and lipoic acid with participation of heme oxygenase 1.

    PubMed

    Bobermin, Larissa Daniele; Wartchow, Krista Minéia; Flores, Marianne Pires; Leite, Marina Concli; Quincozes-Santos, André; Gonçalves, Carlos-Alberto

    2015-07-01

    Ammonia is a metabolite that, at high concentrations, is implicated in neurological disorders, such as hepatic encephalopathy (HE), which is associated with acute or chronic liver failure. Astrocytes are considered the primary target of ammonia toxicity in the central nervous system (CNS) because glutamine synthetase (GS), responsible for ammonia metabolism in CNS, is an astrocytic enzyme. Thus, neuronal dysfunction has been associated as secondary to astrocytic impairment. However, we demonstrated that ammonia can induce direct effects on neuronal cells. The cell viability was decreased by ammonia in SH-SY5Y cells and cerebellar granule neurons. In addition, ammonia induced increased reactive oxygen species (ROS) production and decreased GSH intracellular content, the main antioxidant in CNS. As ammonia neurotoxicity is strongly associated with oxidative stress, we also investigated the potential neuroprotective roles of the antioxidants, resveratrol (RSV) and lipoic acid (LA), against ammonia toxicity in cerebellar granule neurons. RSV and LA were able to prevent the oxidative damage induced by ammonia, maintaining the levels of ROS production and GSH close to basal values. Both antioxidants also decreased ROS production and increased GSH content under basal conditions (in the absence of ammonia). Moreover, we showed that heme oxygenase 1 (HO1), a protein associated with protection against stress conditions, is involved in the beneficial effects of RSV and LA in cerebellar granule neurons. Thus, this study reinforces the neuroprotective effects of RSV and LA. Although more studies in vivo are required, RSV and LA could represent interesting therapeutic strategies for the management of HE. PMID:26003724

  2. Synergistic Application of Black Tea Extracts and Lactic Acid Bacteria in Protecting Human Colonocytes against Oxidative Damage.

    PubMed

    Zhao, Danyue; Shah, Nagendra P

    2016-03-23

    In view of the potential of lactic acid bacteria (LAB) to enhance the antioxidant activity of food products, this work explored the effectiveness of LAB fermented black tea samples in alleviating H2O2-induced oxidative stress in human colonocytes. The antioxidant capacity of tea samples was evaluated in terms of cyto-protectiveness, mitochondria membrane potential (Δψm)-stabilizing activity, ROS-inhibitory effect, and antioxidant enzyme-modulating activity. The effect on oxidative DNA damage and repair was studied in CCD 841 by comet assay. Results showed that the protective effect of tea pretreatment was more pronounced in normal cells (CCD 841) than in carcinomas (Caco-2), and fermented samples were invariably more effective. Higher cell viability and Δψm were maintained and ROS production was markedly inhibited with tea pretreatment. The fermented tea samples also remarkably stimulated DNA repair, resulting in fewer strand breaks and oxidative lesions. Our study implied that LAB fermentation may be an efficient way to enhance the antioxidative effectiveness of black tea flavonoid-enriched foods. PMID:26790920

  3. Molecular Mechanisms of Lipoic Acid Protection against Aflatoxin B1-Induced Liver Oxidative Damage and Inflammatory Responses in Broilers

    PubMed Central

    Ma, Qiugang; Li, Yan; Fan, Yu; Zhao, Lihong; Wei, Hua; Ji, Cheng; Zhang, Jianyun

    2015-01-01

    Alpha-lipoic acid (α-LA) was evaluated in this study for its molecular mechanisms against liver oxidative damage and inflammatory responses induced by aflatoxin B1 (AFB1). Birds were randomly allocated into four groups with different diets for three weeks: a basal diet, a 300 mg/kg α-LA supplementation in a basal diet, a diet containing 74 μg/kg AFB1, and 300 mg/kg α-LA supplementation in a diet containing 74 μg/kg AFB1. In the AFB1 group, the expression of GSH-PX mRNA was down-regulated (p < 0.05), and the levels of lipid peroxide and nitric oxide were increased (p < 0.05) in the chicken livers compared to those of the control group. Additionally, the mRNA level of the pro-inflammatory factor interleukin-6 was up-regulated significantly (p < 0.05), the protein expressions of both the nuclear factor kappa B (NF-κB) p65 and the inducible nitric oxide synthase were enhanced significantly (p < 0.05) in the AFB1 group. All of these negative effects were inhibited by α-LA. These results indicate that α-LA may be effective in preventing hepatic oxidative stress, down-regulating the expression of hepatic pro-inflammatory cytokines, as well as inhibiting NF-κB expression. PMID:26694462

  4. Molecular Mechanisms of Lipoic Acid Protection against Aflatoxin B₁-Induced Liver Oxidative Damage and Inflammatory Responses in Broilers.

    PubMed

    Ma, Qiugang; Li, Yan; Fan, Yu; Zhao, Lihong; Wei, Hua; Ji, Cheng; Zhang, Jianyun

    2015-12-01

    Alpha-lipoic acid (α-LA) was evaluated in this study for its molecular mechanisms against liver oxidative damage and inflammatory responses induced by aflatoxin B₁ (AFB₁). Birds were randomly allocated into four groups with different diets for three weeks: a basal diet, a 300 mg/kg α-LA supplementation in a basal diet, a diet containing 74 μg/kg AFB₁, and 300 mg/kg α-LA supplementation in a diet containing 74 μg/kg AFB₁. In the AFB₁ group, the expression of GSH-PX mRNA was down-regulated (p < 0.05), and the levels of lipid peroxide and nitric oxide were increased (p < 0.05) in the chicken livers compared to those of the control group. Additionally, the mRNA level of the pro-inflammatory factor interleukin-6 was up-regulated significantly (p < 0.05), the protein expressions of both the nuclear factor kappa B (NF-κB) p65 and the inducible nitric oxide synthase were enhanced significantly (p < 0.05) in the AFB₁ group. All of these negative effects were inhibited by α-LA. These results indicate that α-LA may be effective in preventing hepatic oxidative stress, down-regulating the expression of hepatic pro-inflammatory cytokines, as well as inhibiting NF-κB expression. PMID:26694462

  5. Titania Deposition on PMR-15

    NASA Technical Reports Server (NTRS)

    Meador, Mary B.; Sutter, James K.; Pizem, Hillel; Gershevitz, Olga; Goffer, Yossi; Frimer, Aryeh A.; Sukenik, Chaim N.; Sampathkumaran, Uma; Milhet, Xavier; McIlwain, Alan

    2005-01-01

    The formation, degree of crystallinity and adherence of dense titania (TiO2) thin film coatings on a high-temperature polyimide resin (PMR-15) can be influenced by the chemical composition of the polymer surface. Furthermore, solution deposition conditions can be adjusted to provide additional control over the morphology and crystallinity of the titania films. Recipes for solution-based titania deposition that used a slowly-hydrolyzing titanium fluoride salt in the presence of boric acid as a fluoride scavenger allowed growth of films up to 750 nm thick in 22 h. By adjusting solution pH and temperature, either amorphous titania or oriented crystalline anatase films could be formed. Surface sulfonate groups enhance the adhesion of solution-deposited oxide thin film coatings. While most sulfonation procedures severely damaged the PMR-15 surface, the use of chlorosulfonic acid followed by hydrolysis of the installed chlorosulfonyl groups provided effective surface sulfonation without significant surface damage. In some cases, the oxide deposition solution caused partial hydrolysis of the polymer surface, which itself was sufficient to allow adhesion of the titania film through chelation of titanium ions by exposed benzoic acid groups on the polymer surface.

  6. Effects of β-glucan pretreatment on acetylsalicylic acid-induced gastric damage: An experimental study in rats

    PubMed Central

    Ozkan, Orhan Veli; Ozturk, Oktay Hasan; Aydin, Mehmet; Yilmaz, Nigar; Yetim, Ibrahim; Nacar, Ahmet; Oktar, Suleyman; Sogut, Sadik

    2010-01-01

    Background: NSAIDs have been found to induce gastrointestinal tract damage. Recently, it has been suggested that this might be mediated by lipid peroxidation. Objective: The aim of this study was to assess the potential protective effects of β-glucan against acetylsalicylic acid (ASA-induced gastric damage by means of its antioxidant capacity in an experimental rat model. Methods: Thirty-two male Wistar albino rats (200–250 g) were randomized into 4 groups consisting of 8 rats each. The β-glucan group received 50 mg/kg β-glucan once a day for 10 days and 30 minutes before anesthesia. The ASA group received saline once a day for 10 days and 300 mg/kg (20 mg/mL) ASA as a single dose, 4 hours before anesthesia. The ASA+β-glucan group was administered 50 mg/kg β-glucan once a day for 10 days and 30 minutes before anesthesia. Additionally, 300 mg/kg (20 mg/mL) ASA was administered as a single dose, 4 hours before anesthesia. The control group received saline once a day for 10 days and 30 minutes before anesthesia. All medications were administered by intragastric gavage. The stomach from each rat was dissected and divided into 2 parts for histologic and biochemical analysis. Gastric tissue malondialdehyde (MDA), nitric oxide (NO) levels, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities were determined for oxidative parameter analysis. Results: The gastroprotective and antioxidant effects of β-glucan appeared to attenuate the ASA-induced gastric tissue damage. Compared with the control group, MDA and NO levels and CAT and GSH-Px activities were significantly increased in the stomachs of ASA-treated rats (MDA, 4.12 [0.44] to 13.41 [1.05] μmol/L; NO, 8.04 [7.25–9.10] vs 30.35 [22.34–37.95] μmol/g protein; CAT, 0.050 [0.004] to 0.083 [0.003] k/g protein; GSH-Px, 0.57 [0.42–0.66] to 1.55 [1.19–1.76] U/L; all, P < 0.001), whereas SOD activity was significantly decreased in the same group (291 [29] to 124 [6] U/mL; P

  7. Effects of acid deposition on dissolution of carbonate stone during summer storms in the Adirondack Mountains, New York, 1987-89

    USGS Publications Warehouse

    Schuster, Paul F.; Reddy, Michael M.; Sherwood, S.I.

    1994-01-01

    This study is part of a long-term research program designed to identify and quantify acid rain damage to carbonate stone. Acidic deposition accelerates the dissolution of carbonate-stone monuments and building materials. Sequential sampling of runoff from carbonate-stone (marble) and glass (reference) microcatchments in the Adirondack Mountains in New York State provided a detailed record of the episodic fluctuations in rain rate and runoff chemistry during individual summer storms. Rain rate and chemical concentrations from carbonate-stone and glass runoff fluctuated three to tenfold during storms. Net calcium-ion concentrations from the carbonatestone runoff, a measure of stone dissolution, typically fluctuated twofold during these storms. High net sulfate and net calcium concentrations in the first effective runoff at the start of a storm indicated that atmospheric pollutants deposited on the stone surface during dry periods formed calcium sulfate minerals, an important process in carbonate stone dissolution. Dissolution of the carbonate stone generally increased up to twofold during coincident episodes of low rain rate (less than 5 millimeters per hour) and decreased rainfall (glass runoff) pH (less than 4.0); episodes of high rain rate (cloudbursts) were coincident with a rapid increase in rainfall pH and also a rapid decrease in the dissolution of carbonate-stone. During a storm, it seems the most important factors causing increased dissolution of carbonate stone are coincident periods of low rain rate and decreased rainfall pH. Dissolution of the carbonate stone decreased slightly as the rain rate exceeded about 5 millimeters per hour, probably in response to rapidly increasing rainfall pH during episodes of high rain rate and shorter contact time between the runoff and the stone surface. High runoff rates resulting from cloudbursts remove calcium sulfate minerals formed during dry periods prior to storms and also remove dissolution products formed in large

  8. Streamwater acid-base chemistry and critical loads of atmospheric sulfur deposition in Shenandoah National Park, Virginia.

    PubMed

    Sullivan, T J; Cosby, B J; Webb, J R; Dennis, R L; Bulger, A J; Deviney, F A

    2008-02-01

    A modeling study was conducted to evaluate the acid-base chemistry of streams within Shenandoah National Park, Virginia and to project future responses to sulfur (S) and nitrogen (N) atmospheric emissions controls. Many of the major stream systems in the park have acid neutralizing capacity (ANC) less than 20 microeq/L, levels at which chronic and/or episodic adverse impacts on native brook trout are possible. Model hindcasts suggested that none of these streams had ANC less than 50 microeq/L in 1900. Model projections, based on atmospheric emissions controls representative of laws already enacted as of 2003, suggested that the ANC of those streams simulated to have experienced the largest historical decreases in ANC will increase in the future. The levels of S deposition that were simulated to cause streamwater ANC to increase or decrease to three specified critical levels (0, 20, and 50 microeq/L) ranged from less than zero (ANC level not attainable) to several hundred kg/ha/year, depending on the selected site and its inherent acid-sensitivity, selected ANC endpoint criterion, and evaluation year for which the critical load was calculated. Several of the modeled streams situated on siliciclastic geology exhibited critical loads <0 kg/ha/year to achieve ANC >50 microeq/L in the year 2040, probably due at least in part to base cation losses from watershed soil. The median modeled siliciclastic stream had a calculated critical load to achieve ANC >50 microeq/L in 2100 that was about 3 kg/ha/year, or 77% lower than deposition in 1990, representing the time of model calibration. PMID:17492359

  9. Curcumin and Ellagic acid synergistically induce ROS generation, DNA damage, p53 accumulation and apoptosis in HeLa cervical carcinoma cells.

    PubMed

    Kumar, Devbrat; Basu, Soumya; Parija, Lucy; Rout, Deeptimayee; Manna, Sanjeet; Dandapat, Jagneshwar; Debata, Priya Ranjan

    2016-07-01

    Cervical cancer and precancerous lesions of the cervix continue to be a global health issue, and the medication for the treatment for chronic HPV infection so far has not been effective. Potential anticancer and anti HPV activities of two known phytochemicals, Curcumin and Ellagic acid were evaluated in HeLa cervical cancer cells. Curcumin is a natural compound found in the root of Curcuma longa plant and Ellagic acid a polyphenol found in fruits of strawberries, raspberries and walnuts. The combination of Curcumin and Ellagic acid at various concentrations showed better anticancer properties than either of the drug when used alone as evidenced by MTT assay. Besides this, Curcumin and Ellagic acid also restore p53, induce ROS formation and DNA damage. Mechanistic study further indicated that Curcumin and Ellagic acid show anti-HPV activity as evidenced by decrease in the HPV E6 oncoprotein on HeLa cells. PMID:27261574

  10. IMPLICATIONS OF A GRADIENT IN ACID AND ION DEPOSITION ACROSS THE NORTHERN GREAT LAKES STATES

    EPA Science Inventory

    Average precipitation pH, 1979-1982, declines from west to east from 5.3 to 4.3 along a cross section of sites in Minnesota, Wisconsin, and Michigan. The answers questions about the seasonal and geographic pattern of anthropogenic acid precursor emissions and reaction products (S...

  11. PRELIMINARY EXPOSURE STUDY TO DETERMINE THE EFFECTS OF ACID DEPOSITION ON COATED STEEL SUBSTRATES

    EPA Science Inventory

    This report describes the progress that has been made within the Coatings Effect Research Program that the Environmental Protection Agency conducts for Task Group VII within the National Acidic Precipitation Assessment Program. his project involves the evaluation of the effects o...

  12. ACID DEPOSITION SYSTEM (ADS) FOR STATISTICAL REPORTING: SYSTEM DESIGN AND USER'S CODE MANUAL

    EPA Science Inventory

    This document is a general purpose description of the ADS data management system. It explains to acid precipitation monitoring network managers how their data is being merged with that from other networks. For the researcher, this document defines what information is available in...

  13. CHEMICAL TRANSFORMATION MODULES FOR EULERIAN ACID DEPOSITION MODELS. VOLUME 1. THE GAS-PHASE CHEMISTRY

    EPA Science Inventory

    This study focuses on the review and evaluation of mechanistic and kinetic data for the gas-phase reactions that lead to the production of acidic substances in the environment. A master mechanism is designed that treats oxides, sulfur dioxide, ozone, hydrogen peroxide, ammonia, t...

  14. CHEMICAL TRANSFORMATION MODULES FOR EULERIAN ACID DEPOSITION MODELS. VOLUME 2. THE AQUEOUS-PHASE CHEMISTRY

    EPA Science Inventory

    This study focuses on the review and evaluation of mechanistic and kinetic data for aqueous-phase reactions that lead to the production of acidic substances in the environment. The intent of this research is to provide a framework that can be used to develop a state-of-the-art aq...

  15. ELECTROCHEMICALLY DEPOSITED POLYMER-COATED GOLD ELECTRODES SELECTIVE FOR 2,4-DICHLOROPHENOXYACETIC ACID

    EPA Science Inventory

    Electropolymerized membranes on gold electrodes doped with 2,4-dichlorophenoxyacetic acid (2,4-D) were prepared from a solution containing resorcinol, o-phenylenediamine and 2,4-D. Fourier Transform Infrared (FTIR) spectroscopy was used to evaluate the incorporation and interact...

  16. Anthropogenically driven changes in chloride complicate interpretation of base cation trends in lakes recovering from acidic deposition.

    PubMed

    Rosfjord, Catherine H; Webster, Katherine E; Kahl, Jeffrey S; Norton, Stephen A; Fernandez, Ivan J; Herlihy, Alan T

    2007-11-15

    Declines in Ca and Mg in low ANC lakes recovering from acidic deposition are widespread across the northern hemisphere. We report overall increases between 1984 and 2004 in the concentrations of Ca + Mg and Cl in lakes representing the statistical population of nearly 4000 low ANC lakes in the northeast U.S. Increases in Cl occurred in nearly all lakes in urbanized southern New England, but only 18% of lakes in more remote Maine had Cl increases. This spatial pattern implicates road salt application as the major source of the increased Cl salts. Among the 48% of the lake population classified as salt-affected, the median changes in Cl (+133 microeq/L) and Ca + Mg (+47 microeq/ L) were large and positive in direction over the 20 years. However, in the unaffected lakes, Cl remained stable and Ca + Mg decreased (-3 microeq/L), consistent with reported long-term trends in base cations of acid-sensitive lakes. This discrepancy between the Cl groups suggests that changes in ion exchange processes in salt-affected watersheds have altered the geochemical cycling of Ca and Mg. One policy-relevant implication is that waters influenced by Cl salts complicate regional assessments of surface water recovery from "acid rain" related to the passage of the Clean Air Act. PMID:18075075

  17. Chemical recovery of surface waters across the northeastern united states from reduced inputs of acidic deposition: 1984-2001.

    PubMed

    Warby, Richard A F; Johnson, Chris E; Driscoll, Charles T

    2005-09-01

    Changes in lake water chemistry between 1984 and 2001 at 130 stratified random sites across the northeastern United States were studied to evaluate the population-level effects of decreases in acidic deposition. Surface-water S04(2-) concentrations decreased across the region at a median rate of -1.53 microequiv L(-1) year(-1). Calcium concentrations also decreased, with a median rate of -1.73 microequiv L(-1) year(-1). This decrease in Ca2+ retarded the recovery of surface water acid neutralizing capacity (Gran ANC), which increased at a median rate of 0.66 microequiv L(-1) year(-1). There were small increases in pH in all subregions except central New England and Maine, where the changes were not statistically significant. Median NO3- trends were not significant except in the Adirondacks, where NO3- concentrations increased at a rate of 0.53 microequiv L(-1) year(-1). A regionwide decrease in the concentration of total Al, especially in ponds with low ANC values (ANC < 25 microequiv L(-1)), was observed in the Adirondack subregion. These changes in Al were consistent with the general pattern of increasing pH and ANC. Despite the general pattern of chemical recovery, many ponds remain chronically acidic or are susceptible to episodic acidification. The continued chemical and biological recovery at sites in the northeastern United States will depend on further controls on S and N emissions. PMID:16190211

  18. Role of α-lipoic acid in dextran sulfate sodium-induced ulcerative colitis in mice: studies on inflammation, oxidative stress, DNA damage and fibrosis.

    PubMed

    Trivedi, P P; Jena, G B

    2013-09-01

    Ulcerative colitis affects many people worldwide. Inflammation and oxidative stress play a vital role in its pathogenesis. Previously, we reported that ulcerative colitis leads to systemic genotoxicity in mice. The present study was aimed at elucidating the role of α-lipoic acid in ulcerative colitis-associated local and systemic damage in mice. Experimental colitis was induced using 3%w/v dextran sulfate sodium in drinking water for 2 cycles. α-Lipoic acid was administered in a co-treatment (20, 40, 80 mg/kg bw) and post-treatment (80 mg/kg bw) schedule. Various biochemical parameters, histological evaluation, comet and micronucleus assays, immunohistochemistry and western blot analysis were employed to evaluate the effect of α-lipoic acid in mice with ulcerative colitis. The protective effect of α-lipoic acid was mediated through the modulation of nuclear factor kappa B, cyclooxygenase-2, interleukin 17, signal transducer and activator of transcription 3, nuclear erythroid 2-related factor 2, NADPH: quinone oxidoreductase-1, matrix metalloproteinase-9 and connective tissue growth factor. Further, ulcerative colitis led to an increased gut permeability, plasma lipopolysaccharide level, systemic inflammation and genotoxicity in mice, which was reduced with α-lipoic acid treatment. The present study identifies the underlying mechanisms involved in α-lipoic acid-mediated protection against ulcerative colitis and the associated systemic damage in mice. PMID:23793040

  19. Groundtruthing and potential for predicting acid deposition impacts in headwater streams using bedrock geology, GIS, angling, and stream chemistry.

    PubMed

    Kirby, C S; McInerney, B; Turner, M D

    2008-04-15

    Atmospheric acid deposition is of environmental concern worldwide, and the determination of impacts in remote areas can be problematic. Rainwater in central Pennsylvania, USA, has a mean pH of approximately 4.4. Bedrock varies dramatically in its ability to neutralize acidity. A GIS database simplified reconnaissance of non-carbonate bedrock streams in the Valley and Ridge Province and identified potentially chronically impacted headwater streams, which were sampled for chemistry and brook trout. Stream sites (n=26) that originate in and flow through the Tuscarora had a median pH of 5.0 that was significantly different from other formations. Shawangunk streams (n=6) and non-Tuscarora streams (n=20) had a median pH of 6.0 and 6.3, respectively. Mean alkalinity for non-Tuscarora streams (2.6 mg/L CaCO(3)) was higher than the mean for Tuscarora streams (0.5 mg/L). Lower pH and alkalinity suggest that the buffering capability of the Tuscarora is inferior to that of adjacent sandstones. Dissolved aluminum concentrations were much higher for Tuscarora streams (0.2 mg/L; approximately the lethal limit for brook trout) than for non-Tuscarora streams (0.03 mg/L) or Shawangunk streams (0.02 mg/L). Hook-and-line methods determined the presence/absence of brook trout in 47 stream reaches with suitable habitat. Brook trout were observed in 21 of 22 non-Tuscarora streams, all 6 Shawangunk streams, and only 9 of 28 Tuscarora stream sites. Carefully-designed hook-and-line sampling can determine the presence or absence of brook trout and help confirm biological impacts of acid deposition. 15% of 334 km of Tuscarora stream lengths are listed as "impaired" due to atmospheric deposition by the Pennsylvania Department of Environmental Protection. 65% of the 101 km of Tuscarora stream lengths examined in this study were impaired. PMID:18258282

  20. Lactation Affects Isolated Mitochondria and Its Fatty Acid Composition but Has No Effect on Tissue Protein Oxidation, Lipid Peroxidation or DNA-Damage in Laboratory Mice

    PubMed Central

    Valencak, Teresa G.; Raith, Johannes; Staniek, Katrin; Gille, Lars; Strasser, Alois

    2016-01-01

    Linking peak energy metabolism to lifespan and aging remains a major question especially when focusing on lactation in females. We studied, if and how lactation affects in vitro mitochondrial oxygen consumption and mitochondrial fatty acid composition. In addition, we assessed DNA damage, lipid peroxidation and protein carbonyls to extrapolate on oxidative stress in mothers. As model system we used C57BL/6NCrl mice and exposed lactating females to two ambient temperatures (15 °C and 22 °C) while they nursed their offspring until weaning. We found that state II and state IV respiration rates of liver mitochondria were significantly higher in the lactating animals than in non-lactating mice. Fatty acid composition of isolated liver and heart mitochondria differed between lactating and non-lactating mice with higher n-6, and lower n-3 polyunsaturated fatty acids in the lactating females. Surprisingly, lactation did not affect protein carbonyls, lipid peroxidation and DNA damage, nor did moderate cold exposure of 15 °C. We conclude that lactation increases rates of mitochondrial uncoupling and alters mitochondrial fatty acid composition thus supporting the “uncoupling to survive” hypothesis. Regarding oxidative stress, we found no impact of lactation and lower ambient temperature and contribute to growing evidence that there is no linear relationship between oxidative damage and lactation. PMID:26805895

  1. Carcinogenic damage to deoxyribonucleic acid is induced by near-infrared laser pulses in multiphoton microscopy via combination of two- and three-photon absorption

    NASA Astrophysics Data System (ADS)

    Nadiarnykh, Oleg; Thomas, Giju; Van Voskuilen, Johan; Sterenborg, Henricus J. C. M.; Gerritsen, Hans C.

    2012-11-01

    Nonlinear optical imaging modalities (multiphoton excited fluorescence, second and third harmonic generation) applied in vivo are increasingly promising for clinical diagnostics and the monitoring of cancer and other disorders, as they can probe tissue with high diffraction-limited resolution at near-infrared (IR) wavelengths. However, high peak intensity of femtosecond laser pulses required for two-photon processes causes formation of cyclobutane-pyrimidine-dimers (CPDs) in cellular deoxyribonucleic acid (DNA) similar to damage from exposure to solar ultraviolet (UV) light. Inaccurate repair of subsequent mutations increases the risk of carcinogenesis. In this study, we investigate CPD damage that results in Chinese hamster ovary cells in vitro from imaging them with two-photon excited autofluorescence. The CPD levels are quantified by immunofluorescent staining. We further evaluate the extent of CPD damage with respect to varied wavelength, pulse width at focal plane, and pixel dwell time as compared with more pronounced damage from UV sources. While CPD damage has been expected to result from three-photon absorption, our results reveal that CPDs are induced by competing two- and three-photon absorption processes, where the former accesses UVA absorption band. This finding is independently confirmed by nonlinear dependencies of damage on laser power, wavelength, and pulse width.

  2. Genetic parameters and crossbreeding effects of fat deposition and fatty acid profiles in Iberian pig lines.

    PubMed

    Ibáñez-Escriche, N; Magallón, E; Gonzalez, E; Tejeda, J F; Noguera, J L

    2016-01-01

    The aim of this study was to estimate the genetic and environmental parameters and crossbreeding effects on fatty acid and fat traits in the Iberian pig. Our final goal is to explore target selection traits and define crossbreeding strategies. The phenotypes were obtained under intensive management from 470 animals in a diallelic experiment involving Retinto, Torbiscal, and Entrepelado lines. The data set was composed of backfat thickness at the fourth rib (BFT), intramuscular fat (IMF) in the longissimus thoracis (LT), and the fatty acid profile for IMF and subcutaneous fat (SCF) traits. Data were analyzed through a Bayesian bivariate animal model by using a reparameterization of Dickerson's model. The results obtained showed an important genetic determinism for all traits analyzed with heritability ranging from 0.09 to 0.67. The common environment litter effect also had an important effect on IMF (0.34) and its fatty acid composition (0.06-0.53) at slaughter. The additive genetic correlation between BFT and IMF (additive genetic correlation [] = 0.31) suggested that it would be possible to improve lean growth independent of the IMF with an appropriate selection index. Furthermore, the high additive genetic correlation ( = 0.68) found between MUFA tissues would seem to indicate that either the LT or SCF could be used as the reference tissue for MUFA selection. The relevance of the crossbreeding parameters varied according to the traits analyzed. Backfat thickness at the fourth rib and the fatty acid profile of the IMF showed relevant differences between crosses, mostly due to line additive genetic effects associated with the Retinto line. On the contrary, those for IMF crosses were probably mainly attributable to heterosis effects. Particularly, heterosis effects were relevant for the Retinto and Entrepelado crosses (approximately 16% of the trait), which could be valuable for a crossbreeding system involving these lines. PMID:26812309

  3. Preliminary study of the acid deposition in the Tijuana Area (Mexico)

    SciTech Connect

    Bravo, H.; Sosa, R.; Torres, R. )

    1988-01-01

    Transboundary air pollution is of widespread international concern. Tijuana, Mexico, and San Diego, California, form one of the fastest growing border communities in the world. Projections place the current population of three million residents at nearly five million by the year 2000. Although the two cities are divided by an international border they share a common air base. Tijuana and southern portions of San Diego County are particularly affected by the exchange of air flow through the Tijuana River Canyon. The development of an air pollution acid rain monitoring and sampling program across the border, particularly in Tijuana is imperative because of a planned new Tijuana industrial city, large numbers of existing industries without adequate emission controls, and thousands of vehicles generated pollutants on both sides of the border. The first steps toward an acid rain study along the mexican border began in 1985, with a project between the National Council of Science and Technology - (CONACYT) and the Center of the Atmospheric Sciences of the University of Mexico (CCA, UNAM). The goal of this project is to obtain acid rain data from five sites along the border. One of these sites is Tijuana, B.C., Mexico. The data obtained are reported in the paper.

  4. Nanocrystalline hard chromium electrodeposition from trivalent chromium bath containing carbamide and formic acid: Structure, composition, electrochemical corrosion behavior, hardness and wear characteristics of deposits

    NASA Astrophysics Data System (ADS)

    Danilov, F. I.; Protsenko, V. S.; Gordiienko, V. O.; Kwon, S. C.; Lee, J. Y.; Kim, M.

    2011-07-01

    The paper is devoted to the structure, composition and properties investigations of coatings obtained from a sulfate trivalent chromium bath containing formic acid and carbamide as the complexing agents. The results indicate that the deposits have a nanocrystalline type of structure-there are regions with atomic ordered arrangement in bulk material with the average size of 3-5 nm. Carbon is present as chromium carbide within the coating and it is distributed uniformly inside of the deposit. The deposits under study exhibit particular electrochemical behavior (absence of the active dissolution range in acid solution). The hardness of these coatings does not differ noticeably from that typical of coatings obtained in Cr(VI)-based baths. The wear characteristics of the deposits from the proposed bath are somewhat better than in the case of a common hexavalent chromium bath.

  5. Application of citrate as a tricarboxylic acid (TCA) cycle intermediate, prevents diabetic-induced heart damages in mice

    PubMed Central

    Liang, Qianqian; Wang, Baoyu; Pang, Lingxia; Wang, Youpei; Zheng, Meiqin; Wang, Qing; Yan, Jingbin; Xu, Jinzhong

    2016-01-01

    Objective(s): Higher cellular reactive oxygen species (ROS) levels is important in reducing cellular energy charge (EC) by increasing the levels of key metabolic protein, and nitrosative modifications, and have been shown to damage the cardiac tissue of diabetic mice. However, the relation between energy production and heart function is unclear. Materials and Methods: Streptozotocin (STZ, 150 mg/kg body weight) was injected intraperitoneally once to mice that had been fasted overnight for induction of diabetes. After diabetic induction, mice received citrate (5 µg/kg) through intraperitoneal injection every other day for 5 weeks. The caspase-3, plasminogen activator inhibitor 1 (PAI1), protein kinase B (PKB), commonly known as AKT and phosphorylated-AKT (p-AKT) proteins were examined to elucidate inflammation and apoptosis in the heart. For histological analysis, heart samples were fixed with 10% formalin and stained with hematoxylin-eosin (HE) and Sirius red to assess pathological changes and fibrosis. The expression levels[AGA1] of marker proteins, tyrosine nitration, activity of ATP synthase and succinyl-CoA3-ketoacid coenzyme A transferase-1 (SCOT), and EC were measured. Results: Intraperitoneal injection of citrate significantly reduced caspase-3 and PAI-1 protein levels and increased p-AKT level on the 5th week; EC in the heart was found to be increased as well. Further, the expression level, activity, and tyrosine nitration of ATP synthase and SCOT were not affected after induction of diabetes. Conclusion: Results indicate that application of citrate, a tricarboxylic acid (TCA) cycle intermediate, might alleviate cardiac dysfunction by reducing cardiac inflammation, apoptosis, and increasing cardiac EC. PMID:27096063

  6. Interrelationships among hydrologic-budget components of a northern Wisconsin seepage lake and implications for acid-deposition modeling

    USGS Publications Warehouse

    Wentz, D.A.; Rose, W.J.

    1989-01-01

    Components of the hydrologic budget for a northern Wisconsin seepage lake were analyzed by applying correlation and regression techniques to monthly data. Analyses for the 1981-83 water years revealed a statistically significant, direct relationship between storage change and precipitation-evaporation balance. Ground-water outflow was negatively correlated with ground-water inflow, and this relationship was influenced by similar relationships for both hydraulic gradients and cross-sectional areas in outflow versus inflow regions of the lake. Neither ground-water outflow nor inflow was significantly related to precipitation, evaporation, storage change, or lake stage; this may reflect a lag in response time of the ground-water system compared to the lake. The results (1) emphasize the complexity of factors that influence ground-water interactions with seepage lakes and (2) suggest the importance of completing detailed hydrologic studies of these systems before mechanistic models, such as those developed to predict effects of acid deposition, are applied.

  7. Analysis of laser energy deposition leading to damage and ablation of HfO2 and Nb2O5 single layers submitted to 500 fs pulses at 1030 and 343 nm

    NASA Astrophysics Data System (ADS)

    Douti, Dam-Bé; Bégou, Thomas; Lemarchand, Fabien; Lumeau, Julien; Commandré, Mireille; Gallais, Laurent

    2016-07-01

    Laser- induced damage thresholds and morphologies of laser ablated sites on dielectric thin films are studied based on experiments and simulations. The films are single layers of hafnia and niobia deposited on fused silica substrates with a magnetron sputtering technique. Laser experiments are conducted with 500 fs pulses at 1030 and 343 nm, and the irradiated sites are characterized with optical profilometry and scanning electron microscopy. The results, i.e., LIDT and damage morphologies, are compared to simulations of energy deposition in the films based on the single rate equation for electron excitation, taking into account transient optical properties of the films during the pulse. The results suggest that a critical absorbed energy as a damage criterion gives consistent results both with the measured LIDT and the observed damage morphologies at fluences close to the damage threshold. Based on the numerical and experimental results, the determined LIDT evolution with the wavelength is described as nearly constant in the near-infrared region, and as rapidly decreasing with laser wavelength in the visible and near-ultraviolet regions.

  8. Use of soil-streamwater relationships to assess regional patterns of acidic deposition effects in the northeastern USA

    USGS Publications Warehouse

    Siemion, Jason; Lawrence, Gregory B.; Murdoch, Peter S.

    2013-01-01

    Declines of acidic deposition levels by as much as 50% since 1990 have led to partial recovery of surface waters in the northeastern USA but continued depletion of soil calcium through this same period suggests a disconnection between soil and surface water chemistry. To investigate the role of soil-surface water interactions in recovery from acidification, the first regional survey to directly relate soil chemistry to stream chemistry during high flow was implemented in a 4144-km2 area of the Catskill region of New York, where acidic deposition levels are among the highest in the East. More than 40% of 95 streams sampled in the southern Catskill Mountains were determined to be acidified and had inorganic monomeric aluminum concentrations that exceeded a threshold that is toxic to aquatic biota. More than 80% likely exceeded this threshold during the highest flows, but less than 10% of more than 100 streams sampled were acidified in the northwestern portion of the region. Median Oa horizon soil base saturation ranged from 50% to 80% at 200 sites across the region, but median base saturation in the upper 10 cm of the B horizon was less than 20% across the region and was only 2% in the southern area. Aluminum is likely to be interfering with root uptake of calcium in the mineral horizon in approximately half the sampled watersheds. Stream chemistry was highly variable over the Catskill region and, therefore, did not always reflect the calcium depletion of the B horizon that our sampling suggested was nearly ubiquitous throughout the region.

  9. Growth and reproductive ecology of the eastern brook trout, Salvelinus fontinalis, in streams of differing vulnerability to acidic atmospheric deposition

    SciTech Connect

    Light, R.W.

    1983-01-01

    Three naturally infertile streams of differing vulnerability to acidic atmospheric deposition were studied to determine the status of their brook trout, Salvelinus fontinalis, populations and associated benthic communities. Of the three streams, Upper Three Runs was judged to be the least fertile, followed by Little Fishing Creek, with Roaring Run being the most fertile. The median weighted pH of acidic deposition impacting the watersheds was 3.8 for Upper Three Runs and 4.0 for Little Fishing Creek and Roaring Run. Brook trout from Roaring Run grew at a similar rate to those from Little Fishing Creek, with trout from Upper Three Runs showing the slowest growth. Roaring Run brook trout also had the highest relative condition of the three streams. Brook trout from Roaring Run and Little Fishing Creek generally matured one year later (age group II) than those from Upper Three Runs. Early maturity may be selected for in Upper Three Runs due to small annual increases in fecundity in higher age groups. Although the data were limited, there was a trend for brook trout from Upper Three Runs to produce fewer and larger ova. Roaring Run had higher volumes of benthos during fall and summer, and higher numbers during fall. Roaring Run and Little Fishing Creek had more, larger crayfish present, which added significantly to the volume of benthos in these streams. Qualitatively, Upper Three Runs had more shredders and fewer scrapers on a volume basis than the other two streams. On a per fish basis, the drift available to the fish in Roaring Run was always highest in volume, and highest in number during fall and spring. The brook trout from Roaring Run therefore had an advantage over those in the other two streams, by having a higher drift available per fish.

  10. Effects of acidic deposition on nutrient uptake, nutrient cycling and growth processes of vegetation in the spruce-fir ecosystem

    SciTech Connect

    McLaughlin, S.B.; Garten, C.T.; Wullschleger, S.D.

    1996-10-16

    This report summarizes progress in three years of field research designed to evaluate biological and chemical indicators of the current and future health of the Southern Appalachian spruce-fir ecosystem. The emphasis of this research has been on the identification and understanding of mechanisms through which current levels of acidic deposition are impacting ecosystem processes. The identification of these principal mechanisms and key biological indicators of change was designed to improve our capabilities to detect, monitor, and assess the effects of air quality regulations and attendant future air quality changes on ecosystem response. Individual research tasks focused on the following research areas: (1) the significance of foliar uptake of atmospheric sources of nitrogen in relationship to plant utilization of N from available soil reserves; (2) linkages between atmospheric inputs to the soil surface, solution chemistry, and decomposition in the upper organic soil horizons; (3) effects of soil solution chemistry on uptake of cations and aluminum by fine roots; and (4) the effects of varying rates of calcium supply on carbon metabolism of Fraser fir and red spruce, and the relationship between calcium levels in wood cells and integrity of wood formed in bole and branches. Each of the individual tasks was designed to focus upon a mechanism or process that we consider critical to understanding chemical and biological linkages. These linkages will be important determinants in understanding the basis of past and potential future responses of the high elevation Southern Appalachian Forest to acidic deposition and other co-occurring environmental stresses. This report contains (1) background and rationale for the research undertaken in 1992-94; (2) a summary of principal research findings; (3) publications from this research; and (4) characterization of data sets produced by this research which will be the basis of future research, analyses and/or publications.

  11. Impact of acid and trace metals deposition on freshwater invertebrates in north-eastern Fennoscandia and Kola Peninsula

    SciTech Connect

    Yakovlev, V.

    1996-12-31

    Freshwater invertebrate communities in a total 400 lakes and streams in northeastern Norway, Finnish Lapland and the Kola Peninsula, subjected to the atmospheric deposition were studied. The severe influence of toxic heavy metals, dusts from smelters and mineral enrichment factories were found in the Kola Peninsula. The negative acidification effects on benthic communities were found in the Jarfjord (Norway), Enontekio, Ranua-Posio and Kittila-Kolari (Finnish Lapland) areas and in the Kola Peninsula (Russia). Taxa groups, known to be sensitive to acidification, such as gammarids, snails, mayflies, stone flies, were represented with few species and in a low abundance. Heavy metals accumulation in biota is recorded in areas surrounding nickel smelters in the Kola Peninsula. The metal concentration invertebrates in remote areas is rather wide and depend on an air deposition, characteristics of lake catchment areas, as well as water acidity. The environmental variables, such as lake hydrological type, altitude of lakes, dominant substratum type, abundance of macrophytes and mosses in sampling area, content of pollutants in water also show significant relationships with metal concentration in invertebrates. The most severe negative effects on biota were found in waters with low pH and simultaneously contaminated by heavy metals. The biological method for estimation of simultaneously water acidification and contamination is suggested.

  12. Valproic acid alleviates memory deficits and attenuates amyloid-β deposition in transgenic mouse model of Alzheimer's disease.

    PubMed

    Xuan, Ai-Guo; Pan, Xue-Bing; Wei, Peng; Ji, Wei-Dong; Zhang, Wen-Juan; Liu, Ji-Hong; Hong, Le-Peng; Chen, Wen-Liang; Long, Da-Hong

    2015-02-01

    In the brains of patients with Alzheimer's disease (AD) and transgenic AD mouse models, astrocytes and microglia activated by amyloid-β (Aβ) contribute to the inflammatory process that develops around injury in the brain. Valproic acid (VPA) has been shown to have anti-inflammatory function. The present study intended to explore the therapeutic effect of VPA on the neuropathology and memory deficits in APPswe/PS1ΔE9 (APP/PS1) transgenic mice. Here, we report that VPA-treated APP/PS1 mice markedly improved memory deficits and decreased Aβ deposition compared with the vehicle-treated APP/PS1 mice. Moreover, the extensive astrogliosis and microgliosis as well as the increased expression in interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the hippocampus and cortex of APP/PS1 transgenic mice were significantly reduced following administration of VPA, which attenuated neuronal degeneration. Concomitantly, VPA alleviated the levels of p65 NF-κB phosphorylation and enhanced the levels of acetyl-H3, Bcl-2, and phospho-glycogen synthase kinase (GSK)-3β that occurred in the hippocampus of APP/PS1 transgenic mice. These results demonstrate that VPA could significantly ameliorate spatial memory impairment and Aβ deposition at least in part via the inhibition of inflammation, suggesting that administration of VPA could provide a therapeutic approach for AD. PMID:24854198

  13. Influence of the organic solvents on the properties of the phosphoric acid dopant emulsion deposited on multicrystalline silicon wafers

    NASA Astrophysics Data System (ADS)

    Bouhafs, D.; Moussi, A.; Boumaour, M.; Abaïdia, S. E. K.; Mahiou, L.; Messaoud, A.

    2007-05-01

    This study is devoted to the formation of an n+p emitter for multicrystalline silicon (mc-Si) solar cells for photovoltaic (PV) application. The atomization technique has been used to make the emitter from H3PO4 phosphoric acid as a doping source. The doping emulsion has been optimized using several organic solvents. H3PO4 was mixed with one of these solutions: ethanol, 2-butanol, isopropanol alcohol and deionized water. The volume concentration of H3PO4 does not exceed 20% of the total volume emulsion. The deposit characteristics of the emulsion change with the organic solvent. H3PO4 : 2-butanol gives the best deposited layer with acceptable adherence and uniformity on silicon surface. Fourier transform infrared characterizations show the presence of organic and mineral phosphorous bonds in the formed layer. The obtained emitters are characterized by a junction depth in the range 0.2-0.75 µm and a sheet resistance of about 10-90 Ω/square. Such a low cost dopant source combined with a continuous spray process can effectively reduce the cost per Wp of the PV generator.

  14. Valproic acid reduces insulin-resistance, fat deposition and FOXO1-mediated gluconeogenesis in type-2 diabetic rat.

    PubMed

    Khan, Sabbir; Kumar, Sandeep; Jena, Gopabandhu

    2016-06-01

    Recent evidences highlighted the role of histone deacetylases (HDACs) in insulin-resistance, gluconeogenesis and islet function. HDACs can modulate the expression of various genes, which directly or indirectly affect glucose metabolism. This study was aimed to evaluate the role of valproic acid (VPA) on fat deposition, insulin-resistance and gluconeogenesis in type-2 diabetic rat. Diabetes was developed in Sprague-Dawley rats by the combination of high-fat diet and low dose streptozotocin. VPA at the doses of 150 and 300 mg/kg/day and metformin (positive control) 150 mg/kg twice daily for 10 weeks were administered by oral gavage. Insulin-resistance, dyslipidemia and glycemia were evaluated by biochemical estimations, while fat accumulation and structural alteration were assessed by histopathology. Protein expression and insulin signaling were evaluated by western blot and immunohistochemistry. VPA treatment significantly reduced the plasma glucose, HbA1c, insulin-resistance, fat deposition in brown adipose tissue, white adipose tissue and liver, which are comparable to metformin treatment. Further, VPA inhibited the gluconeogenesis and glucagon expression as well as restored the histopathological alterations in pancreas and liver. Our findings provide new insights on the anti-diabetic role of VPA in type-2 diabetes mellitus by the modulation of insulin signaling and forkhead box protein O1 (FOXO1)-mediated gluconeogenesis. Since VPA is a well established clinical drug, the detailed molecular mechanisms of the present findings can be further investigated for possible clinical use. PMID:26944797

  15. Different responses of two Mosla species to potassium limitation in relation to acid rain deposition*

    PubMed Central

    Wang, Meng; Gu, Bao-jing; Ge, Ying; Liu, Zhen; Jiang, De-an; Chang, Scott X.; Chang, Jie

    2009-01-01

    The increasingly serious problem of acid rain is leading to increased potassium (K) loss from soils, and in our field investigation, we found that even congenerically relative Mosla species show different tolerance to K-deficiency. A hydroponic study was conducted on the growth of two Mosla species and their morphological, physiological and stoichiometric traits in response to limited (0.35 mmol K/L), normal (3.25 mmol K/L) and excessive (6.50 mmol K/L) K concentrations. Mosla hangchowensis is an endangered plant, whereas Mosla dianthera a widespread weed. In the case of M. hangchowensis, in comparison with normal K concentration, K-limitation induced a significant reduction in net photosynthetic rate (P n), soluble protein content, and superoxide dismutase (SOD) activity, but an increase in malondialdehyde (MDA) concentration. However, leaf mass ratio (LMR) and root mass ratio (RMR) were changed little by K-limitation. In contrast, for M. dianthera, K-limitation had little effect on P n, soluble protein content, SOD activity, and MDA concentration, but increased LMR and RMR. Critical values of N (nitrogen):K and K:P (phosphorus) ratios in the shoots indicated that limitation in acquiring K occurred under K-limited conditions for M. hangchowensis but not for M. dianthera. We found that low K content in natural habitats was a restrictive factor in the growth and distribution of M. hangchowensis, and soil K-deficiency caused by acid rain worsened the situation of M. hangchowensis, while M. dianthera could well acclimate to the increasing K-deficiency. We suggest that controlling the acid rain and applying K fertilizers may be an effective way to rescue the endangered M. hangchowensis. PMID:19650194

  16. Protective effect of ascorbic acid against double-strand breaks in giant DNA: Marked differences among the damage induced by photo-irradiation, gamma-rays and ultrasound

    NASA Astrophysics Data System (ADS)

    Ma, Yue; Ogawa, Naoki; Yoshikawa, Yuko; Mori, Toshiaki; Imanaka, Tadayuki; Watanabe, Yoshiaki; Yoshikawa, Kenichi

    2015-10-01

    The protective effect of ascorbic acid against double-strand breaks in DNA was evaluated by single-molecule observation of giant DNA (T4 DNA; 166 kbp) through fluorescence microscopy. Samples were exposed to three different forms of radiation: visible light, γ-ray and ultrasound. With regard to irradiation with visible light, 1 mM AA reduced the damage down to ca. 30%. Same concentration of AA decreased the damage done by γ-ray to ca. 70%. However, AA had almost no protective effect against the damage caused by ultrasound. This significant difference is discussed in relation to the physico-chemical mechanism of double-strand breaks depending on the radiation source.

  17. Morphologic Damage of Rat Alveolar Epithelial Type II Cells Induced by Bile Acids Could Be Ameliorated by Farnesoid X Receptor Inhibitor Z-Guggulsterone In Vitro

    PubMed Central

    Huang, Yaowei; Hou, Xusheng; Wu, Wenyu; Nie, Lei; Tian, Yinghong; Lu, Yanmeng

    2016-01-01

    Objective. To determine whether bile acids (BAs) affect respiratory functions through the farnesoid X receptor (FXR) expressed in the lungs and to explore the possible mechanisms of BAs-induced respiratory disorder. Methods. Primary cultured alveolar epithelial type II cells (AECIIs) of rat were treated with different concentrations of chenodeoxycholic acid (CDCA) in the presence or absence of FXR inhibitor Z-guggulsterone (GS). Then, expression of FXR in nuclei of AECIIs was assessed by immunofluorescence microscopy. And ultrastructural changes of the cells were observed under transmission electron microscope and analyzed by Image-Pro Plus software. Results. Morphologic damage of AECIIs was exhibited in high BAs group in vitro, with high-level expression of FXR, while FXR inhibitor GS could attenuate the cytotoxicity of BAs to AECIIs. Conclusions. FXR expression was related to the morphologic damage of AECIIs induced by BAs, thus influencing respiratory functions. PMID:27340672

  18. Direct comparison of DNA damage, isomerization of urocanic acid and edema in the mouse produced by three commonly used artificial UV light sources.

    PubMed

    Yarosh, D B; Kibitel, J; Ullrich, S E; Kim, T H; Ananthaswamy, H N; Krien, P; Fourtanier, A; Kripke, M L

    1999-05-01

    Exposure to sunlight can result in a number of harmful effects, including sunburn, erythema, premature aging of the skin, immune suppression and skin cancer. Studies designed to understand the underlying mechanisms often depend upon the use of artificial sources of UV radiation. Unfortunately, conclusions from different laboratories using different lamps often conflict, and it is entirely possible that the different spectra of sunlights used in each may be a source of conflict. To minimize confounding variables, we employed two of the more commonly used UV light sources, fluorescent sunlamps, such as the FS-40 and Kodacel-filtered FS-40 sunlamps, and a xenon arc solar simulator and compared, in one series of standardized experiments, the effects of each light source on DNA damage, urocanic acid isomerization and edema formation. The dose-response curves, calculated by linear regression or curve fitting were compared. The data indicate that DNA damage and urocanic acid isomerization were more sensitive to shorter wavelengths of UV than longer wavelengths, and the biological endpoint of edema most closely correlated with the induction of DNA damage. The results emphasize the dominance of shorter wavelengths within the UV spectrum in damaging biological tissues, even when the solar simulator, which contains significant amounts of UVA, was used and demonstrate that each light source has a characteristic pattern of induction of biochemical and biological endpoints. PMID:10333763

  19. Clinical significance of elevated serum A-FABP and free fatty acid in neonates with hypoxic ischemic brain damage

    PubMed Central

    Li, Mei; Jiang, Lian; Zhang, Huifen; Wang, Dandan; Zhang, Min; Zhang, Lianshan

    2016-01-01

    The main function of adipocyte fatty acid-binding protein (A-FABP) is to regulate fatty acid metabolism as its molecular chaperone. The clinical significance of A-FABP in hypoxic-ischemic brain damage (HIBD) neonates is not yet clear. Free fatty acid (FFA) in cerebral cortex increases along with hypoxia ischemia degree. Thus, we aimed to investigate whether FFA can induce A-FABP expression and elevate the serum A-FABP level in HIBD neonates. In the present study, 42 HIBD neonates were selected including 11 cases as mild, 16 cases as moderate and 15 cases as severe. The serum was collected from peripheral vein at 72 h after the first visit (acute stage) and 7 days after birth (recovery stage), and the serum from 10 normal neonates was used as the control. The serum level of A-FABP and FFA in 42 neonates with acute phase and recovery phase HIBD were detected using ELISA and copper colorimetric method. The overall serum A-FABP content in HIBD neonates at the acute stage was significantly higher compared to the normal neonates (P<0.05). The serum A-FABP level in severe HIBD neonates was significantly higher than that in mild HIBD, moderate HIBD and normal neonates (P<0.05). The serum FFA level in HIBD neonates at the acute stage was 1,521.57±605.63 µmol/l, which was significantly higher than that in the normal neonates 838.24±294.22 µmol/l. The serum FFA levels in mild, moderate and severe HIBD neonates were significantly higher than those in the normal neonates. The overall A-FABP level in HIBD neonates at the recovery stage was significantly lower compared to the acute stage, which was significant in severe HIBD neonates. A-FABP levels in mild and moderate HIBD neonates at recovery stage were decreased compared with the acute stage, although there was no statistical difference. There was a positive correlation between serum A-FABP and FFA in HIBD neonates at acute stage (r=0.369, P<0.05). In conclusion, serum A-FABP and FFA levels were signifcantly increased in

  20. An Adirondack Watershed Data Base: Attribute and mapping information for regional acidic deposition studies

    SciTech Connect

    Rosen, A.E.; Olson, R.J.; Gruendling, G.K.; Bogucki, D.J.; Malanchuk, J.L.; Durfee, R.C.; Turner, R.S.; Adams, K.B.; Wilson, D.L.; Coleman, P.R.

    1988-12-01

    The Adirondack Watershed Data Base (AWDB) provides a means to test hypotheses concerning the relative importance of various watershed attributes that may contribute to increased acidification of Adirondack surface waters. The AWDB is a valuable resource for the study of other ecological phenomena. The AWDB consists of digital watershed boundaries and digital geographic data, stored within a geographic information system, and watershed/lake attribute data stored in a data management system (SAS) for 463 Adirondack headwater lakes. Attributes include watershed morphology, physiography, bedrock, soils, land cover, wetlands, disturbances (e.g., cabins, fire, and logging), beaver activity, precipitation, and atmospheric deposition. Over 600 variables are available for each watershed. These data can be combined with water chemistry data and fish community status for regional-scale examinations of watershed attributes that may account for variability and change in water chemistry and fish populations in the Adirondacks. This report describes the design of the AWDB, documents sources and history of the data; defines the format of the AWDB contents; and characterizes the data using summary statistics, frequency bar charts, and other graphics. In addition, it provides information necessary for researchers using the data base on their own computer systems. 37 refs., 42 figs., 4 tabs.

  1. Chemical recovery of surface waters across the Northeastern United States from reduced inputs of acidic deposition: 1984-2001

    SciTech Connect

    Richard A.F. Warby; Chris E. Johnson; Charles T. Driscoll

    2005-09-01

    Changes in lake water chemistry between 1984 and 2001 at 130 stratified random sites across the northeastern United States were studied to evaluate the population-level effects of decreases in acidic deposition. Surface-water SO{sub 4}{sup 2-} concentrations decreased across the region at a median rate of -1.53 {mu}equiv L{sup -1} year{sup -1}. Calcium concentrations also decreased, with a median rate of -1.73 {mu}equiv L{sup -1} year{sup -1}. This decrease in Ca{sub 2+} retarded the recovery of surface water acid neutralizing capacity (Gran ANC), which increased at a median rate of 0.66 {mu}equiv L{sup -1} year{sup -1}. There were small increases in pH in all subregions except central New England and Maine, where the changes were not statistically significant. Median NO{sub 3}{sup -} trends were not significant except in the Adirondacks, where NO{sub 3}{sup -} concentrations increased at a rate of 0.53 equiv L{sup -1} year{sup -1}. A regionwide decrease in the concentration of total Al, especially in ponds with low ANC values (ANC {lt} 25 {mu}equiv L{sup -1}), was observed in the Adirondack subregion. These changes in Al were consistent with the general pattern of increasing pH and ANC. Despite the general pattern of chemical recovery, many ponds remain chronically acidic or are susceptible to episodic acidification. The continued chemical and biological recovery at sites in the northeastern United States will depend on further controls on S and N emissions. 27 refs., 4 figs., 3 tabs.

  2. Effects of balancing crystalline amino acids in diets containing heat-damaged soybean meal or distillers dried grains with solubles fed to weanling pigs.

    PubMed

    Almeida, F N; Htoo, J K; Thomson, J; Stein, H H

    2014-10-01

    Two experiments were conducted to investigate if adjustments in diet formulations either based on total analysed amino acids or standardized ileal digestible (SID) amino acids may be used to eliminate negative effects of including heat-damaged soybean meal (SBM) or heat-damaged corn distillers dried grains with solubles (DDGS) in diets fed to weanling pigs. In Experiment 1, four corn-SBM diets were formulated. Diet 1 contained non-autoclaved SBM (315 g/kg), and this diet was formulated on the basis of analysed amino acid concentrations and using SID values from the AminoDat® 4.0 database. Diet 2 was similar to Diet 1 in terms of ingredient composition, except that the non-autoclaved SBM was replaced by autoclaved SBM at 1 : 1 (weight basis). Diet 3 was formulated using autoclaved SBM and amino acid inclusions in the diet were adjusted on the basis of analysed total amino acid concentrations in the autoclaved SBM and published SID values for non-autoclaved SBM (AminoDat® 4.0). Diet 4 also contained autoclaved SBM, but the formulation of this diet was adjusted on the basis of analysed amino acids in the autoclaved SBM and SID values that were adjusted according to the degree of heat damage in this source of SBM. Pigs (160; initial BW: 10.4 kg) were allotted to the four treatments with eight replicate pens per treatment in a randomized complete block design. Diets were fed to pigs for 21 days. The gain to feed ratio (G : F) was greater (P<0.05) for pigs fed Diet 1 compared with pigs fed the other diets and pigs fed Diet 4 had greater (P<0.05) G : F than pigs fed Diet 2. In Experiment 2, 144 pigs (initial BW: 9.9 kg) were allotted to four diets with eight replicate pens per diet. The four diets contained corn, SBM (85 g/kg) and DDGS (220 g/kg), and were formulated using the concepts described for Experiment 1, except that heat-damaged DDGS, but not heat-damaged SBM, was used in the diets. Pigs fed Diet 1 had greater (P<0.05) G : F than pigs fed Diet 2, but no

  3. Responses of streams in central Appalachian Mountain region to reduced acidic deposition--comparisons with other regions in North America and Europe.

    PubMed

    Chen, Yushun; Lin, Lian-Shin

    2009-03-15

    Data from 5 wet deposition stations and 21 streams during 1980-2006 were analyzed to investigate chemical responses of streams to reduced acidic deposition in the central Appalachian Mountain region of West Virginia, USA. Wet deposition of acidic anions (i.e., sulfate, nitrate, and chloride) and hydrogen ions decreased significantly during the studied time period. Stream sulfate showed a delayed response to the reduced acidic deposition, and showed a decrease in the 2000s (-5.54 microeq L(-1) yr(-1)) and the whole period (-0.49 microeq L(-1) yr(-1)). No significant trend of stream nitrate+nitrite and chloride was observed. Stream alkalinity increased in the 1990s (+23.33 microeq L(-1) yr(-1)) and the whole period (+7.26 microeq L(-1) yr(-1)). Stream hydrogen ions decreased in the 1990s (-0.002 microeq L(-1) yr(-1)), 2000s (-0.001 microeq L(-1) yr(-1)), and the whole period (-0.001 microeq L(-1) yr(-1)). Compared with most acidic streams and lakes in the United States and Europe, a lower decreasing rate of hydrogen ions and higher increasing rate of alkalinity were observed in the alkaline West Virginian streams in the 1990s. However, due to their initial negative or zero alkalinity values, those acidic streams showed a higher percent increase in alkalinity than that in the alkaline West Virginian streams (from 800 microeq L(-1) yr(-1) to 1200 microeq L(-1) yr(-1)). Total aluminum in the West Virginian streams decreased in the 1990s (-0.67 micromol L(-1) yr(-1)) and the whole period (-0.22 micromol L(-1) yr(-1)). The current study advanced our understanding of streams' responses to the reduced acidic deposition in the Mid-Appalachians since the passage of the 1970 and 1990 Amendments to the United States Clean Air Act (US CAAA). PMID:19073337

  4. Effect of betaine on the hepatic damage from orotic acid-induced fatty liver development in rats.

    PubMed

    Cha, Jae-Young; Kim, Hyeong-Soo; Moon, Hyung-In; Cho, Young-Su

    2011-12-13

    Betaine prevents hepatic damage caused by ethanol and carbone tetrachloride (CCl4) in rats. Present study was to investigate the effect of betaine on the hepatic microsomal triglyceride transfer protein (MTP) mRNA expression in orotic acid (OA)-induced fatty liver in rats. OA feeding was attributed to the significant increase in the hepatic levels of triglyceride and the serum levels of ALT and AST and resulted in typical histology of fatty liver contained numerous largely fat droplets. While concomitant supplementation of betaine to OA diet was slightly reduced the hepatic triglyceride concentrations and was significantly decreased ALT activity. Hepatic MTP mRNA expression by OA treatment increased by 14% despite triglyceride accumulation in the liver in OA treatment rats relative to rats fed a normal diet without OA supplemented, but MTP expression by simultaneous supplementation of OA and betaine was slightly decreased by 7.9% as compared to the OA-feeding rats. A significant elevation of TBARS contents in the liver homogenate, microsome, and mitochondrial fractions of the OA-feeding rats compared with the normal rats, however, these increases were significantly or slightly decreased by simultaneous addition of OA and betaine. The increases of hepatic OA and betaine levels in OA feeding rats was also found when compared to the normal rats, but these increases were significantly lowered in the concomitant supplementation OA and betaine. The content of Fe was significantly increased in the OA feeding rats, but this elevation showed significantly recovered as low as the normal level by concomitant with OA and betaine. Zinc content was also significantly decreased in the OA feeding rats compared with the normal rats, but this reduction was more significantly elevated by concomitant with OA and betaine. Hepatic glutathione content in the OA feeding rats was similar to that of the normal rats, but this content was slightly reduced without statistically significant

  5. Evaluating long-term trends in littoral benthic macroinvertebrate communities of lakes recovering from acid deposition.

    PubMed

    Lento, Jennifer; Dillon, Peter J; Somers, Keith M

    2012-12-01

    The Mann-Kendall test has been proposed as a nonparametric method to evaluate trends in long-term water quality datasets with missing values, serial correlation, and non-normality. However, this test has rarely been used to evaluate long-term trends in biological data. In this study, we used the Mann-Kendall test to evaluate trends in 15 years of data on benthic macroinvertebrate communities from 17 Precambrian Shield lakes. We also used the van Belle and Hughes test of trend homogeneity to assess whether common among-lake temporal trends existed. We assumed that evidence of a common regional trend among lakes would support the hypothesis of long-term biological recovery from past acidification. We found decreasing proportions of Chironomidae and increasing proportions of Ephemeroptera, Plecoptera, and Trichoptera (EPT) in both single-lake and multi-lake trend analysis. Moreover, six of the nine lakes with significant trends in more than one benthos metric displayed a significant decrease in Chironomidae and increase in EPT concurrently, indicating a shift towards more acid-sensitive taxa. Weak trends in several of the biological metrics indicated that recovery in these lakes has been impeded. Results of this study indicate that the Mann-Kendall and van Belle and Hughes trend tests are useful statistical tools to evaluate long-term patterns in biological data. PMID:22193633

  6. Tracking the Effects of Acidic Deposition in Medium-Scale Forested Watersheds of the Eastern US

    NASA Astrophysics Data System (ADS)

    Murdoch, P. S.; Shanley, J. B.; Huntington, T. G.

    2001-05-01

    The US Geological Survey Hydrologic Benchmark Network (HBN) was established in the mid-1960's for continuously monitoring flow and seasonally monitoring water quality in medium-scale naturally-vegetated watersheds (100-500 km2) throughout the United States. Unlike small watershed research sites, the HBN sites are large enough to contain well-developed riparian zones, and as such are more representative of a natural reference landscape for assessing the relative effects of air pollution, development and agriculture on water quality in the US. During the past three years more frequent water quality monitoring (biweekly and during stormflows) has been established at 5 of these stations in the eastern United States. The stations are located in eastern Tennessee (Little River, 275 km2), western North Carolina (Cataloochee Creek, 127km2), north-central Pennsylvania (Young Woman's Creek, 120 km2), southeastern New York (Neversink River, 168 km2), and north- western Maine (Wild River, 180 km2), and thus lie along southeastern and northeastern gradients of decreasing sulfate deposition from west to east across the region. Concentrations of nitrate and sulfate in streamwater decrease in the Northeastern sites from the southwestern-most watershed to the northeastern-most watershed. Sulfate concentrations have decreased at the Little River, Neversink River and the Wild River during the period of record, but sulfate concentrations in Young Woman's Creek and Cataloochee Creek show no trend. No trend in sulfate concentrations is evident in any of the three Northeastern streams since 1995, when the last significant reduction in emissions was enacted. Sulfate concentrations in Little River have continued to fall since 1995. No trends are observed in ANC in any of the streams, but calcium concentrations in streamwater have decreased in Little River, Neversink River, and Wild River since the 60's. Calcium concentrations in streamwater decrease from a range of 80-120 umole per liter

  7. Target loads of atmospheric sulfur and nitrogen deposition for protection of acid sensitive aquatic resources in the Adirondack Mountains, New York

    USGS Publications Warehouse

    Sullivan, T.J.; Cosby, B.J.; Driscoll, C.T.; McDonnell, T.C.; Herlihy, A.T.; Burns, Douglas A.

    2012-01-01

    The dynamic watershed acid-base chemistry model of acidification of groundwater in catchments (MAGIC) was used to calculate target loads (TLs) of atmospheric sulfur and nitrogen deposition expected to be protective of aquatic health in lakes in the Adirondack ecoregion of New York. The TLs were calculated for two future dates (2050 and 2100) and three levels of protection against lake acidification (acid neutralizing capacity (ANC) of 0, 20, and 50 eq L -1). Regional sulfur and nitrogen deposition estimates were combined with TLs to calculate exceedances. Target load results, and associated exceedances, were extrapolated to the regional population of Adirondack lakes. About 30% of Adirondack lakes had simulated TL of sulfur deposition less than 50 meq m -2 yr to protect lake ANC to 50 eq L -1. About 600 Adirondack lakes receive ambient sulfur deposition that is above this TL, in some cases by more than a factor of 2. Some critical criteria threshold values were simulated to be unobtainable in some lakes even if sulfur deposition was to be decreased to zero and held at zero until the specified endpoint year. We also summarize important lessons for the use of target loads in the management of acid-impacted aquatic ecosystems, such as those in North America, Europe, and Asia. Copyright 2012 by the American Geophysical Union.

  8. Neurochemical evidence that 3-methylglutaric acid inhibits synaptic Na+,K+-ATPase activity probably through oxidative damage in brain cortex of young rats.

    PubMed

    Ribeiro, César Augusto João; Hickmann, Fernanda Hermes; Wajner, Moacir

    2011-02-01

    3-Methylglutaconic aciduria (MGTA) comprehends a group of disorders biochemically characterized by accumulation of 3-methylglutaric acid (MGA), 3-methylglutaconic acid (MGT) and occasionally 3-hydroxyisovaleric acid (OHIVA). Although neurological symptoms are common in the affected individuals, the mechanisms of brain damage are poorly known. In the present study we investigated the in vitro effect MGA, MGT and OHIVA, at concentrations ranging from 0.1 to 5.0mM, on bioenergetics and oxidative stress in synaptosomal preparations isolated from cerebral cortex of young rats. MGA significantly reduced mitochondrial redox potential (25%), as determined by resazurin reduction, and inhibited the activity of Na(+),K(+)-ATPase (30%), whereas MGT and OHIVA did not modify these parameters. Moreover, the inhibitory effect elicited by MGA on Na(+),K(+)-ATPase activity was totally prevented by co-incubation with the scavenging antioxidants creatine and melatonin, implying a role for reactive species in this effect. MGA also increased 2',7'-dichlorofluorescein (DCFH) oxidation (30%), reinforcing that this organic acid induces reactive species production. The present data indicate that MGA compromises mitochondrial function, elicits reactive species production and inhibits the activity of a crucial enzyme implicated in neurotransmission. It is therefore presumed that these deleterious effects may play a role in the pathophysiology of the brain damage observed in patients affected by disorders in which MGA accumulates. PMID:21050883

  9. Effects of acid rain and sulfur dioxide on marble dissolution

    SciTech Connect

    Schuster, P.F.; Reddy, M.M. ); Sherwood, S.I. )

    1994-01-01

    Acid precipitation and the dry deposition of sulfur dioxide (SO[sub 2]) accelerate damage to carbonate-stone monuments and building materials. This study identified and quantified environmental damage to a sample of Vermont marble during storms and their preceding dry periods. Results from field experiments indicated the deposition of SO[sub 2] gas to the stone surface during dry periods and a twofold increase in marble dissolution during coincident episodes of low rain rate and decreased rainfall pH. The study is widely applicable to the analysis of carbonate-stone damage at locations affected by acid rain and air pollution.

  10. Effects of acid rain and sulfur dioxide on marble dissolution

    USGS Publications Warehouse

    Schuster, Paul F.; Reddy, Michael M.; Sherwood, Susan I.

    1994-01-01

    Acid precipitation and the dry deposition of sulfur dioxide (SO2) accelerate damage to carbonate-stone monuments and building materials. This study identified and quantified environmental damage to a sample of Vermont marble during storms and their preceding dry periods. Results from field experiments indicated the deposition of SO2 gas to the stone surface during dry periods and a twofold increase in marble dissolution during coincident episodes of low rain rate and decreased rainfall pH. The study is widely applicable to the analysis of carbonate-stone damage at locations affected by acid rain and air pollution.

  11. Soil solution response to experimentally reduced acid deposition in a forest ecosystem

    SciTech Connect

    Alewell, C.; Matzner, E.; Bredemeier, M.; Blanch, K.

    1997-05-01

    In order to measure and predict reversibility of soil solution acidification under experimentally reduced acid input, a manipulation study with artificial {open_quote}preindustrial{close_quote} throughfall was established. A roof was installed underneath the canopy in a Norway Spruce stand of the German Soiling area. Water failing onto the roof was adjusted to clean rain concentrations before redistribution. Soil solutions were collected with suction cup lysimeters at various depths and were analyzed for major ions. The response of soil solution chemistry in the upper soil (10 cm depth) to a reduction of N, SO{sub 4}, and H input was rapid. While NO{sub 3} concentration in deeper soil layers reached input levels after 2 yr of treatment, SO{sub 4} concentration in the seepage water at 1 m depth remained high relative to the reduced input due to a release of formerly stored S from the soil. Aluminum concentration followed a similar pattern as the SO{sub 4} concentrations. The ion concentrations in soil leachate were predicted reasonably well using the MAGIC model with the measured SO{sub 4} sorption isotherms and the throughfall fluxes as model input Although the parameters of the Langmuir isotherm had no significant influence to the prediction of SO{sub 4} concentration in the upper soil layer, they were crucial for the prediction of SO{sub 4} dynamics in deeper soil layers. The model predicted that the reversibility of soil acidification at the Soiling area is delayed for decades due to the release of soil SO{sub 4}. 38 refs., 5 figs., 4 tabs.

  12. Visible-light active thin-film WO{sub 3} photocatalyst with controlled high-rate deposition by low-damage reactive-gas-flow sputtering

    SciTech Connect

    Oka, Nobuto Murata, Akiyo; Nakamura, Shin-ichi; Jia, Junjun; Shigesato, Yuzo; Iwabuchi, Yoshinori; Kotsubo, Hidefumi

    2015-10-01

    A process based on reactive gas flow sputtering (GFS) for depositing visible-light active photocatalytic WO{sub 3} films at high deposition rates and with high film quality was successfully demonstrated. The deposition rate for this process was over 10 times higher than that achieved by the conventional sputtering process and the process was highly stable. Furthermore, Pt nanoparticle-loaded WO{sub 3} films deposited by the GFS process exhibited much higher photocatalytic activity than those deposited by conventional sputtering, where the photocatalytic activity was evaluated by the extent of decomposition of CH{sub 3}CHO under visible light irradiation. The decomposition time for 60 ppm of CH{sub 3}CHO was 7.5 times more rapid on the films deposited by the GFS process than on the films deposited by the conventional process. During GFS deposition, there are no high-energy particles bombarding the growing film surface, whereas the bombardment of the surface with high-energy particles is a key feature of conventional sputtering. Hence, the WO{sub 3} films deposited by GFS should be of higher quality, with fewer structural defects, which would lead to a decrease in the number of centers for electron-hole recombination and to the efficient use of photogenerated holes for the decomposition of CH{sub 3}CHO.

  13. Visible-light active thin-film WO3 photocatalyst with controlled high-rate deposition by low-damage reactive-gas-flow sputtering

    NASA Astrophysics Data System (ADS)

    Oka, Nobuto; Murata, Akiyo; Nakamura, Shin-ichi; Jia, Junjun; Iwabuchi, Yoshinori; Kotsubo, Hidefumi; Shigesato, Yuzo

    2015-10-01

    A process based on reactive gas flow sputtering (GFS) for depositing visible-light active photocatalytic WO3 films at high deposition rates and with high film quality was successfully demonstrated. The deposition rate for this process was over 10 times higher than that achieved by the conventional sputtering process and the process was highly stable. Furthermore, Pt nanoparticle-loaded WO3 films deposited by the GFS process exhibited much higher photocatalytic activity than those deposited by conventional sputtering, where the photocatalytic activity was evaluated by the extent of decomposition of CH3CHO under visible light irradiation. The decomposition time for 60 ppm of CH3CHO was 7.5 times more rapid on the films deposited by the GFS process than on the films deposited by the conventional process. During GFS deposition, there are no high-energy particles bombarding the growing film surface, whereas the bombardment of the surface with high-energy particles is a key feature of conventional sputtering. Hence, the WO3 films deposited by GFS should be of higher quality, with fewer structural defects, which would lead to a decrease in the number of centers for electron-hole recombination and to the efficient use of photogenerated holes for the decomposition of CH3CHO.

  14. Tissue deposition and residue depletion in rainbow trout following continuous voluntary feeding with various levels of melamine or a blend of melamine and cyanuric acid.

    PubMed

    Liu, Haiyan; Xue, Min; Wang, Jia; Qiu, Jing; Wu, Xiufeng; Zheng, Yinhua; Li, Junguo; Qin, Yuchang

    2014-11-01

    This study determined the deposition and depletion in rainbow trout after continuous administration of melamine (MEL) alone or a blend of MEL and cyanuric acid (CYA). The plasma, muscles, kidneys, liver and gills were sampled at 0, 3, 7, 13, 21, 28 and 42d. After the final sampling at 42d, fish from the MEL0.05, MEL20 and MCA groups were fed the control diet (MEL0) for the depletion test. Co-administration with cyanuric acid accelerated the deposition time to the Css for melamine; during the withdrawal phrase, the melamine and CYA concentrations in the tissues decreased exponentially. Compared to the t(½) for single oral administration, the t(½) for melamine and cyanuric acid after 42d continuous feeding was prolonged. The presence of trace CYA in the plasma and kidneys of trout was detected in the MEL20 group, indicating that MEL can convert into CYA in rainbow trout. PMID:25038476

  15. Lower ω-6/ω-3 Polyunsaturated Fatty Acid Ratios Decrease Fat Deposition by Inhibiting Fat Synthesis in Gosling.

    PubMed

    Yu, Lihuai; Wang, Shunan; Ding, Luoyang; Liang, Xianghuan; Wang, Mengzhi; Dong, Li; Wang, Hongrong

    2016-10-01

    The objective of the current study was to investigate the effects of dietary ω-6/ω-3 polyunsaturated fatty acid (PUFA) ratios on lipid metabolism in goslings. One hundred and sixty 21-day-old Yangzhou geese of similar weight were randomly divided into 4 groups. They were fed different PUFA-supplemented diets (the 4 diets had ω-6/ω-3 PUFA ratios of 12:1, 9:1, 6:1, or 3:1). The geese were slaughtered and samples of liver and muscle were collected at day 70. The activities and the gene expression of enzymes involved in lipid metabolism were measured. The results show that the activities of acetyl coenzyme A carboxylase (ACC), malic enzyme (ME), and fatty acid synthase (FAS) were lower (p<0.05), but the activities of hepatic lipase (HL) and lipoprotein lipase (LPL) were higher (p<0.05), in the liver and the muscle from the 3:1 and 6:1 groups compared with those in the 9:1 and 12:1 groups. Expression of the genes for FAS (p<0.01), ME (p<0.01) and ACC (p<0.05) were higher in the muscle of groups fed diets with higher ω-6/ω-3 PUFA ratios. Additionally, in situ hybridization tests showed that the expression intensities of the high density lipoprotein (HDL-R) gene in the 12:1 and 9:1 groups were significantly lower (p<0.01) than that of the 3:1 group in the muscle of goslings. In conclusion, diets containing lower ω-6/ω-3 PUFA ratios (3:1 or 6:1) could decrease fat deposition by inhibiting fat synthesis in goslings. PMID:27189638

  16. [Deposition of exogenous and endogenously generated unsaturated fatty acids in lipid droplets triacylglycerol as a mechanism of its sequestration in epithelial cells].

    PubMed

    Fedorova, E V; Fok, E M; Bakhteeva, V T; Lavrova, E A; Parnova, R G

    2014-08-01

    Neutral lipids are deposited in intracellular compartments called lipid droplets, which are known to be critically implicated in regulation of cellular lipid metabolism. These organelles consist of a core of neutral lipids, mainly triacylglycerol (TAG) and cholesteryl esters, surrounded by phospholipid monolayer. Using Nile red lipid staining and [3H]-arachidonic and [3H]-oleic acids as precursors for lipid biosynthesis, we have evaluated the mechanisms of lipid body induction elicited by exogenous fatty acids within primary cultured epithelial cells from the frog urinary bladder. It was found that arachidonic and oleic acids at concentrations 10-50 tM stimulated lipid droplets formation accompanied by accumulation of TAG and by the significant increase of incorporation of fatty acids into TAG indicating an enhanced TAG biosynthesis. No changes of cholesteryl esters content were observed under these conditions. In cells, prelabelled with [3H]-oleic acids, etomoxir, an inhibitor of O-carnitine palmitroyltansferase 1, decreased oxidation of oleic acid and increased its incorporation into TAG leading to intracellular TAG accumulation. In cells, prelabelled with [3H]-arachidonic acid, diclofenac, an inhibitor of cyclooxygenase 1 and 2, led to significant decrease in cellular PGE2 production and to reesterification of free arachidonic acid to TAG but not to phospholipids. Taking together, these data evidence that in isolated frog urinary bladder epithelial cells, reacylation of unsaturated free fatty acids into TAG is a main route of their metabolic conversion under the conditions of the increased cytosolic level of free fatty acids. PMID:25682688

  17. Nitrogen cycling in s subarctic Alaskan watershed: the role of lichens and the potential effects of acid deposition

    SciTech Connect

    Gunther, A.J.

    1987-01-01

    It has been hypothesized that the loss of nitrogen-fixing lichens due to stress from air pollution could have adverse effects upon nitrogen availability, and thus primary productivity, in some ecosystems. There is general agreement, however, that the ecological role of these lichens has not been sufficiently well defined to determine whether they are keystone species. The objectives of this study were: (1) to examine the importance of nitrogen-fixing lichens to the nitrogen cycle in the drainage of Brooks Lake, Alaska, a nitrogen-limited nursery lake for the commercially important sockeye salmon (Oncorhychus nerka); and (2) to investigate the sensitivity of nitrogen fixation by lichens in this ecosystem to acid deposition. Biological nitrogen fixation was found to be the major source of new nitrogen to the Brooks Lake drainage. The rate of fixation is approximately 3 kg N/ha-yr, which compares to 0.3 kg N/ha-yr in precipitation and only 0.02 kg N/ha-yr in returning adult salmon. Cyanophillic lichens contribute about 0.21 kg N/ha-yr. The low levels of nitrogen in precipitation, combined with a lack of nitrogen-fixation activity in open lake waters, indicates that nitrogen in tributary streams is the major source of new nitrogen for Brooks Lake. The measurements of nitrogen inputs, along with estimates of other stocks and flows of nitrogen, were used to construct a steady-state box model of the nitrogen cycle in the drainage.

  18. Changes in aluminum concentrations and speciation in lakes across the northeastern U.S. following reductions in acidic deposition.

    PubMed

    Warby, Richard A F; Johnson, Chris E; Driscoll, Charles T

    2008-12-01

    We surveyed 113 lakes in the northeastern U.S. in 2001 that had previously been sampled in 1986 to evaluate the effects of reductions in acidic deposition on the concentrations and speciation of aluminum (Al). We found ubiquitous decreases in the concentrations of total Al and inorganic monomeric aluminum (Ali) across the region. Median total Al decreased from 1.45 to 1.01 micromol L(-1) across the region, with the largest decrease in the Adirondacks (4.60 micromol L(-1) to 2.59 micromol L(-1)). Organic monomeric aluminum (Alo) also decreased region-wide and in all the subregions except the Adirondacks. The speciation of Ali shifted from largely Al-F complexes in 1986 to largely Al-OH complexes in 2001 in ponds whose concentrations were above the detection limit (>0.7 micromol L(-1)). In 2001, only seven lakes studied, representing a population of 130 lakes in the region, had Al1 concentrations above a toxic limit of 2 micromol L(-1) compared with 20 sample lakes, representing 449 lakes, in 1986. Thus, we estimate that more than 300 lakes in the northeastern United States no longer have summer Ali concentrations at levels considered harmful to aquatic biota. PMID:19192779

  19. Aquatic amphibians in the Sierra Nevada: Current status and potential effects of acidic deposition on populations. Final report

    SciTech Connect

    Bradford, D.F.; Gordon, M.S.

    1992-05-01

    Toxicity testing indicated that amphibians are at little risk from low pH in water acidified to a pH of 5.0 and aluminum concentrations from 39 to 80 micrograms/l. However, sublethal effects (reduced growth rate and earlier hatching) were observed for pH as high as 5.25 and the aluminum concentrations tested. The authors tested the hypothesis that acidification of habitats in the field has resulted in elimination of populationss from waters most vulnerable to acidification, i.e., low in pH or ANC, or from waters low in ionic strength a condition that increases the sensitivity of amphibians to low pH. The authors surveyed potential breeding sites for two declining and one non-declining species at high elevation within 30 randomly selected survey areas, and compared chemical parameters between sites containing a species and sites lacking the species. No significant differences were found that were consistent with the hypothesis, and water chemistry did not differ among sites inhabited by the three species. These findings imply that acidic deposition is unlikely to have been a cause of recent amphibian population declines in the Sierra Nevada.