Soil Acidification due to Acid Deposition in Southern China

Energy Technology Data Exchange (ETDEWEB)

Liao, Bohan

1998-12-31

Anthropogenic emission of SO{sub 2} and NO{sub x} to the atmosphere has made acid deposition one of the most serious environmental problems. In China, acid deposition research started in the late 1970s. The present thesis is part of a joint Chinese-Norwegian research project. The main goal of the thesis was to investigate the mechanism of soil acidification, to estimate soil responses to acid deposition, and to compare relative soil sensitivity to acidification in southern China. Laboratory experiments and modelling simulations were included. Specifically, the thesis (1) studies the characteristics of anion adsorption and cation release of the soils from southern China, (2) examines the effects of increased ionic strength in the precipitation and the effects of anion adsorption on cation release from the soils, (3) compares the relative sensitivity of these soils to acidification and the potentially harmful effects of acid deposition, (4) estimates likely soil responses to different deposition scenarios, including changes in soil waters and soil properties, and (5) investigates long-term changes in soils and soil waters in the Guiyang catchment due to acid deposition. 218 refs., 31 figs., 23 tabs.

Acid deposition in the northern hemisphere

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S.; Green, S.E.; Lee, D.S.

1987-02-01

Examines the phenomenon of acid deposition: the distribution and magnitude of sources and its actual and potential direct and indirect effects on soils, forests and other vegetation; wildlife, freshwaters, materials and health. The wide range of technological and other controls that are available to reduce the emissions of pollutants contributing to the phenomenon is also examined and includes pre-combustion control of pollutants, removal during combustion and post-combustion control. Also considered are political responses to acidification, acid deposition monitoring in the United Kingdom and the treatment of acidified areas.

Geological aspects of acid deposition

International Nuclear Information System (INIS)

Bricker, O.P.

1984-01-01

The general pattern of rain falling on the earth and reacting with the materials of the lithosphere (the weathering reactions so familiar to every beginning geology student) began soon after the earth was formed and has continued to the present. Anthropogenic additions to the natural acidic components of the atmosphere have increased since the time of the industrial revolution until they now rival or exceed those of the natural system. The severity of the environmental perturbations caused by these anthropogenic additions to the atmosphere has become a hotly debated topic in scientific forums and in the political arena. The six chapters in this book address various aspects of the acid deposition phenomenon from a geological perspective. It is hoped that the geological approach will be useful in bringing the problem more clearly into focus and may shed light on the geochemical processes that modify the chemical composition of acid deposition after it encounters and reacts with the materials of the lithosphere

Effects of deposition time in chemically deposited ZnS films in acidic solution

Energy Technology Data Exchange (ETDEWEB)

Haddad, H.; Chelouche, A., E-mail: azeddinechelouche@gmail.com; Talantikite, D.; Merzouk, H.; Boudjouan, F.; Djouadi, D.

2015-08-31

We report an experimental study on the synthesis and characterization of zinc sulfide (ZnS) single layer thin films deposited on glass substrates by chemical bath deposition technique in acidic solution. The effect of deposition time on the microstructure, surface morphology, optical absorption, transmittance, and photoluminescence (PL) was investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), UV-Vis–NIR spectrophotometry and photoluminescence (PL) spectroscopy. The results showed that the samples exhibit wurtzite structure and their crystal quality is improved by increasing deposition time. The latter, was found to affect the morphology of the thin films as showed by SEM micrographs. The optical measurements revealed a high transparency in the visible range and a dependence of absorption edge and band gap on deposition time. The room temperature PL spectra indicated that all ZnS grown thin films emit a UV and blue light, while the band intensities are found to be dependent on deposition times. - Highlights: • Single layer ZnS thin films were deposited by CBD in acidic solution at 95 °C. • The effect of deposition time was investigated. • Coexistence of ZnS and ZnO hexagonal structures for time deposition below 2 h • Thicker ZnS films were achieved after monolayer deposition for 5 h. • The highest UV-blue emission observed in thin film deposited at 5 h.

Low-Vacuum Deposition of Glutamic Acid and Pyroglutamic Acid: A Facile Methodology for Depositing Organic Materials beyond Amino Acids.

Science.gov (United States)

Sugimoto, Iwao; Maeda, Shunsaku; Suda, Yoriko; Makihara, Kenji; Takahashi, Kazuhiko

2014-01-01

Thin layers of pyroglutamic acid (Pygl) have been deposited by thermal evaporation of the molten L-glutamic acid (L-Glu) through intramolecular lactamization. This deposition was carried out with the versatile handmade low-vacuum coater, which was simply composed of a soldering iron placed in a vacuum degassing resin chamber evacuated by an oil-free diaphragm pump. Molecular structural analyses have revealed that thin solid film evaporated from the molten L-Glu is mainly composed of L-Pygl due to intramolecular lactamization. The major component of the L-Pygl was in β-phase and the minor component was in γ-phase, which would have been generated from partial racemization to DL-Pygl. Electron microscopy revealed that the L-Glu-evaporated film generally consisted of the 20 nm particulates of Pygl, which contained a periodic pattern spacing of 0.2 nm intervals indicating the formation of the single-molecular interval of the crystallized molecular networks. The DL-Pygl-evaporated film was composed of the original DL-Pygl preserving its crystal structures. This methodology is promising for depositing a wide range of the evaporable organic materials beyond amino acids. The quartz crystal resonator coated with the L-Glu-evaporated film exhibited the pressure-sensing capability based on the adsorption-desorption of the surrounding gas at the film surface.

Microbial activity in an acid resin deposit: Biodegradation potential and ecotoxicology in an extremely acidic hydrocarbon contamination

International Nuclear Information System (INIS)

Kloos, Karin; Schloter, Michael; Meyer, Ortwin

2006-01-01

Acid resins are residues produced in a recycling process for used oils that was in use in the forties and fifties of the last century. The resin-like material is highly contaminated with mineral oil hydrocarbons, extremely acidic and co-contaminated with substituted and aromatic hydrocarbons, and heavy metals. To determine the potential for microbial biodegradation the acid resin deposit and its surroundings were screened for microbial activity by soil respiration measurements. No microbial activity was found in the core deposit. However, biodegradation of hydrocarbons was possible in zones with a lower degree of contamination surrounding the deposit. An extreme acidophilic microbial community was detected close to the core deposit. With a simple ecotoxicological approach it could be shown that the pure acid resin that formed the major part of the core deposit, was toxic to the indigenous microflora due to its extremely low pH of 0-1. - Acidity is the major toxic factor of the extremely hydrophobic and acidic mixed contamination found in an acid resin deposit

Acid deposition: sources, effects and controls

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S. (ed.)

1989-01-01

The purpose of this collection of 19 papers is to review our understanding of the cause and effect of acid deposition, to present new data that assist in the provision of a fuller understanding of cause, process and implication and thus to assist in defining the research agenda of the future. The materials presented are European in perspective, drawn from the Federal Republic of Germany, Hungary, Norway, Sweden and the United Kingdom. The current position as regards deposition monitoring, ecological effects and control technologies is presented in five sections: acid deposition monitoring, freshwater acidification, soils and forest systems, structural materials and control technologies. Each section is introduced by an overview paper outlining the contemporary understanding and identifying areas requiring future work. Specialist papers presenting new data or re-interpretations of existing information comprise the remainder of each section. Four of the papers have been abstracted separately.

Comparative studies on damages to organic layer during the deposition of ITO films by various sputtering methods

Science.gov (United States)

Lei, Hao; Wang, Meihan; Hoshi, Yoichi; Uchida, Takayuki; Kobayashi, Shinichi; Sawada, Yutaka

2013-11-01

Aluminum (III) bis(2-methyl-8-quninolinato)-4-phenylphenolate (BAlq) was respectively bombarded and irradiated by Ar ions, oxygen ions, electron beam and ultraviolet light to confirm damages during the sputter-deposition of transparent conductive oxide (TCO) on organic layer. The degree of damage was evaluated by the photoluminescence (PL) spectra of BAlq. The results confirmed the oxygen ions led to a larger damage and were thought to play the double roles of bombardment to organic layer and reaction with organic layer as well. The comparative studies on PL spectra of BAlq after the deposition of TCO films by various sputtering systems, such as conventional magnetron sputtering (MS), low voltage sputtering (LVS) and kinetic-energy-control-deposition (KECD) system, facing target sputtering (FTS) were performed. Relative to MS, LVS and KECD system, FTS can completely suppress the bombardment of the secondary electrons and oxygen negative ions, and keep a higher deposition rate simultaneously, thus it is a good solution to attain a low-damage sputter-deposition.

Comparative studies on damages to organic layer during the deposition of ITO films by various sputtering methods

Energy Technology Data Exchange (ETDEWEB)

Lei, Hao, E-mail: haolei@imr.ac.cn [State Key Laboratory for Corrosion and Protection, Division of Surface Engineering of Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wang, Meihan [College of Mechanical Engineering, Shenyang University, Shenyang 110044 (China); Hoshi, Yoichi; Uchida, Takayuki; Kobayashi, Shinichi; Sawada, Yutaka [Center for Hyper Media Research, Tokyo Polytechnic University, 1583 Iiyama, Atsugi, Kanagawa 243-0297 (Japan)

2013-11-15

Aluminum (III) bis(2-methyl-8-quninolinato)-4-phenylphenolate (BAlq) was respectively bombarded and irradiated by Ar ions, oxygen ions, electron beam and ultraviolet light to confirm damages during the sputter-deposition of transparent conductive oxide (TCO) on organic layer. The degree of damage was evaluated by the photoluminescence (PL) spectra of BAlq. The results confirmed the oxygen ions led to a larger damage and were thought to play the double roles of bombardment to organic layer and reaction with organic layer as well. The comparative studies on PL spectra of BAlq after the deposition of TCO films by various sputtering systems, such as conventional magnetron sputtering (MS), low voltage sputtering (LVS) and kinetic-energy-control-deposition (KECD) system, facing target sputtering (FTS) were performed. Relative to MS, LVS and KECD system, FTS can completely suppress the bombardment of the secondary electrons and oxygen negative ions, and keep a higher deposition rate simultaneously, thus it is a good solution to attain a low-damage sputter-deposition.

Acid formic effect in zinc coatings obtained by galvanostatic deposition

International Nuclear Information System (INIS)

Lopes, C.; David, M.; Souza, E.C.

2016-01-01

Zinc deposits obtained from electrodeposition is widely used for the purpose of protecting steel substrates from corrosion. They are generally added to Zn deposition bath many additives for improving certain characteristics of the deposit. As far as is known there is no information in literature about the effect of formic acid in corrosion resistance of a Zn deposit. Because it is an acid additive, it has the use of cyclohexylamine, in order for the electrolytic bath continue with a pH equal to the one used commercially, around 5. The main goal of this study is analyze the effect of the formic acid addition in the corrosion resistance of an Zn electrodeposition obtained by galvanostatic deposition. The results obtained by performance tests, cyclic voltammetry and X-ray diffraction showed that the formic acid addition may be promising in combating the corrosion of materials. (author)

Eicosahexanoic Acid (EPA and Docosahexanoic Acid (DHA in Muscle Damage and Function

Directory of Open Access Journals (Sweden)

Eisuke Ochi

2018-04-01

Full Text Available Nutritional supplementation not only helps in improving and maintaining performance in sports and exercise, but also contributes in reducing exercise fatigue and in recovery from exhaustion. Fish oil contains large amounts of omega-3 fatty acids, eicosapentaenoic acid (EPA; 20:5 n-3 and docosahexaenoic acid (DHA; 22:6 n-3. It is widely known that omega-3 fatty acids are effective for improving cardiac function, depression, cognitive function, and blood as well as lowering blood pressure. In the relationship between omega-3 fatty acids and exercise performance, previous studies have been predicted improved endurance performance, antioxidant and anti-inflammatory responses, and effectivity against delayed-onset muscle soreness. However, the optimal dose, duration, and timing remain unclear. This review focuses on the effects of omega-3 fatty acid on muscle damage and function as evaluated by human and animal studies and summarizes its effects on muscle and nerve damage, and muscle mass and strength.

Aquatic chemistry of acid deposition

Energy Technology Data Exchange (ETDEWEB)

Stumm, W; Sigg, L; Schnoor, J L

1987-01-01

The occurrence of acid precipitation in many regions of the Northern hemisphere is a consequnece of human interference in the cycles that unite land, water and atmosphere. The oxidation of carbon, sulfur and nitrogen, resulting mostly from fossil fuel burning, rivals oxidation processes induced by photosynthesis and respiration and disturbs redox conditions in the atmosphere. The paper discusses oxidation-reduction reactions, particularly those involving atmospheric pollutants that are important in the formation of acid precipitation. Topics covered are: a stoichiometric model of acid rain formation; sulfur dioxide and ammonia adsorption; acid neutralizing capacity. The paper concludes that explanations of simple chemical equilibria between gases and water aid our understanding of how acidifying gases become dissolved in cloud water, in droplets of falling rain, or in fog. Rigorous definitions of base- or acid-neutralizing capacities are prerequisites to measuring and interpreting residual acidity in dry and wet deposition and for assessing the disturbance caused by the transfer of acid to terrestrial and aquatic ecosystems. 20 references.

The influence of organic acids in relation to acid deposition in controlling the acidity of soil and stream waters on a seasonal basis

International Nuclear Information System (INIS)

Chapman, Pippa J.; Clark, Joanna M.; Reynolds, Brian; Adamson, John K.

2008-01-01

Much uncertainty still exists regarding the relative importance of organic acids in relation to acid deposition in controlling the acidity of soil and surface waters. This paper contributes to this debate by presenting analysis of seasonal variations in atmospheric deposition, soil solution and stream water chemistry for two UK headwater catchments with contrasting soils. Acid neutralising capacity (ANC), dissolved organic carbon (DOC) concentrations and the Na:Cl ratio of soil and stream waters displayed strong seasonal patterns with little seasonal variation observed in soil water pH. These patterns, plus the strong relationships between ANC, Cl and DOC, suggest that cation exchange and seasonal changes in the production of DOC and seasalt deposition are driving a shift in the proportion of acidity attributable to strong acid anions, from atmospheric deposition, during winter to predominantly organic acids in summer. - Seasonal variations in soil solution ANC is controlled by seasonal variations in seasalt deposition and production of dissolved organic acids

Electrophoretic deposition of composite halloysite nanotube–hydroxyapatite–hyaluronic acid films

Energy Technology Data Exchange (ETDEWEB)

Deen, I. [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Zhitomirsky, I., E-mail: zhitom@mcmaster.ca [Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada)

2014-02-15

Highlights: ► Composite halloysite nanotubes–hydroxyapatite–hyaluronic acid films were prepared. ► Electrophoretic deposition method was used for deposition. ► Natural hyaluronic acid was used as a dispersing, charging and film forming agent. ► Film composition and deposition yield can be varied. ► The films can be used for biomedical implants with controlled release of drugs. -- Abstract: Electrophoretic deposition method has been developed for the deposition of biocomposite films containing halloysite nanotubes (HNTs), hydroxyapatite (HA) and hyaluronic acid. The method is based on the use of natural hyaluronate biopolymer as a dispersing and charging agent for HNT and HA and film forming agent for the fabrication of the composite films. The deposition kinetics was studied by the quartz crystal microbalance method. The composite films were studied by X-ray diffraction, thermogravimetric analysis, differential thermal analysis and electron microscopy. The composite films are promising materials for the fabrication of biomedical implants with advanced functional properties.

Electrophoretic deposition of composite halloysite nanotube–hydroxyapatite–hyaluronic acid films

International Nuclear Information System (INIS)

Deen, I.; Zhitomirsky, I.

2014-01-01

Highlights: ► Composite halloysite nanotubes–hydroxyapatite–hyaluronic acid films were prepared. ► Electrophoretic deposition method was used for deposition. ► Natural hyaluronic acid was used as a dispersing, charging and film forming agent. ► Film composition and deposition yield can be varied. ► The films can be used for biomedical implants with controlled release of drugs. -- Abstract: Electrophoretic deposition method has been developed for the deposition of biocomposite films containing halloysite nanotubes (HNTs), hydroxyapatite (HA) and hyaluronic acid. The method is based on the use of natural hyaluronate biopolymer as a dispersing and charging agent for HNT and HA and film forming agent for the fabrication of the composite films. The deposition kinetics was studied by the quartz crystal microbalance method. The composite films were studied by X-ray diffraction, thermogravimetric analysis, differential thermal analysis and electron microscopy. The composite films are promising materials for the fabrication of biomedical implants with advanced functional properties

Acid deposition. Origins, impacts and abatement strategies

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S. (Manchester Polytechnic, Acid Rain Information Centre (United Kingdom). Dept. of Environmental and Geographical Studies) (ed.)

1991-01-01

The subject of acid deposition is one of the most important of our contemporary environmental problems. Presenting and discussing new data on the sources and effects of such deposition, this book seeks to assist in the definition of our future research requirements and policy developments. It is divided into four broad themes: Emissions, Chemistry and Deposition, Ecosystem Effects (freshwater, soils and forest systems), Effects on Structural Materials, and Mitigation, Control and Management. (orig.) With 130 figs.

Acid deposition study in the Asian countries

Energy Technology Data Exchange (ETDEWEB)

Soon, Ting-Kueh [Tunku Abdul Rahman College, Kuala Lumpur (Malaysia); Lau, Wai-Yoo [Malaysian Scientific Association, Kuala Lumpur (Malaysia)

1996-12-31

The Association of South East Asian Nations or ASEAN is a regional association of seven countries, namely Indonesia, Malaysia, Philippines, Singapore, Thailand, Brunei and Vietnam, located at the south eastern part of the Asian continent. Together with the East Asian States of Japan, China, Korea and Taiwan, this part of the world is experiencing rapid economic growth, especially in the last decade. Rapid industrialization has resulted in an increased demand for energy in the manufacturing and transport sectors, and also for infrastructure development. This has led to a significant increase in gaseous emissions and a corresponding increase in atmospheric acidity. Acid deposition study in the ASEAN countries began in the mid-70s when Malaysia first started her acid rain monitoring network in 1976. This was followed closely by Singapore and the other ASEAN countries in the 80s. By now all ASEAN countries have their own acid rain monitoring networks with a number of these countries extending the monitoring to dry deposition as well.

Effects of acidic deposition on forest and aquatic ecosystems in New York State

Energy Technology Data Exchange (ETDEWEB)

Driscoll, Charles T.; Driscoll, Kimberley M.; Mitchell, Myron J.; Raynal, Dudley J

2003-06-01

Elevated inputs of acidic deposition have deleterious effects on forest and aquatic ecosystems in New York. - Acidic deposition is comprised of sulfuric and nitric acids and ammonium derived from atmospheric emissions of sulfur dioxide, nitrogen oxides, and ammonia, respectively. Acidic deposition has altered soil through depletion of labile pools of nutrient cations (i.e. calcium, magnesium), accumulation of sulfur and nitrogen, and the mobilization of elevated concentrations of inorganic monomeric aluminum to soil solutions in acid-sensitive areas. Acidic deposition leaches essential calcium from needles of red spruce, making this species more susceptible to freezing injury. Mortality among sugar maples appears to result from deficiencies of nutrient cations, coupled with other stresses such as insect defoliation or drought. Acidic deposition has impaired surface water quality in the Adirondack and Catskill regions of New York by lowering pH levels, decreasing acid-neutralizing capacity, and increasing aluminum concentrations. Acidification has reduced the diversity and abundance of aquatic species in lakes and streams. There are also linkages between acidic deposition and fish mercury contamination and eutrophication of estuaries.

The nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit

International Nuclear Information System (INIS)

Kurbonov, A.S.; Mamatov, E.D.; Suleymani, M.; Borudzherdi, A.; Mirsaidov, U.M.

2011-01-01

Present article is devoted to nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit of Tajikistan. The obtaining of boric acid from pre backed danburite concentrate by decomposition of nitric acid was studied. The chemical composition of danburite concentrate was determined. The laboratory study of danburite leaching by nitric acid was conducted. The influence of temperature, process duration, nitric acid concentration on nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit was studied as well. The optimal conditions of nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit, including temperature, process duration, nitric acid concentration and particle size were proposed.

Effects of acid deposition on microbial processes in natural waters

International Nuclear Information System (INIS)

Gilmour, C.C.

1992-01-01

Biogeochemical processes mediated by microorganisms are not adversely affected by the acidification of natural waters to the same extent as are the life cycles of higher organisms. Basic processes, e.g., primary production and organic matter decomposition, are not slowed in moderately acidified systems and do not generally decline above a pH of 5. More specifically, the individual components of the carbon, nitrogen, and sulfur cycles are, with few exceptions, also acid resistant. The influence of acid deposition on microbial processes is more often stimulation of nitrogen and sulfur cycling, often leading to alkalinity production, which mitigates the effect of strong acid deposition. Bacterial sulfate reduction and denitrification in sediments are two of the major processes that can be stimulated by sulfate and nitrate deposition, respectively, and result in ANC (acid-neutralizing capacity) generation. One of the negative effects of acid deposition is increased mobilization and bioaccumulation of some metals. Bacteria appear to play an important role, especially in mercury cycling, with acidification leading to increased bacterial methylation of mercury and subsequent bioaccumulation in higher organisms

Simulated dry deposition of nitric acid near forest edges

NARCIS (Netherlands)

DeJong, JJM; Klaassen, W; Jong, J.J.M. de

1997-01-01

Dry deposition is simulated to understand and generalize observations of enhanced deposition of air pollution near forest edges. Nitric acid is taken as an example as its deposition velocity is often assumed to be determined by turbulent transport only. The simulations are based on the

Laser damage properties of TiO2/Al2O3 thin films grown by atomic layer deposition

International Nuclear Information System (INIS)

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

2011-01-01

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 2 /Al 2 O 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 Φ 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 2 /Al 2 O 3 films, the LIDTs were 6.73±0.47 J/cm 2 and 6.5±0.46 J/cm 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.

Acidic deposition along the Appalachian Trail corridor and its effects on acid-sensitive terrestrial and aquatic resources

Science.gov (United States)

Lawrence, Gregory B.; Sullivan, Timothy J.; Burns, Douglas A.; Bailey, Scott W.; Cosby, Bernard J.; Dovciak, Martin; Ewing, Holly A.; McDonnell, Todd C.; Minocha, Rakesh; Riemann, Rachel; Quant, Juliana; Rice, Karen C.; Siemion, Jason; Weathers, Kathleen C.

2015-01-01

The Appalachian National Scenic Trail (AT), a unit of the National Park Service (NPS), spans nearly 2,200 miles from Georgia to Maine, encompassing a diverse range of ecosystems. Acidic deposition (acid rain) threatens the AT’s natural resources. Acid rain is a result of sulfur (S) and nitrogen (N) compounds produced from fossil fuel combustion, motor vehicles, and agricultural practices. The AT is particularly vulnerable to S and N because it passes along ridgetops that receive higher levels of acid rain than lower valley terrain, and these ridges are often underlain by bedrock with minimal ability to buffer acidic inputs. Further, there are numerous S and N emission sources across the region. In the environment, acidic deposition can lower the pH of streams and soils which can ultimately affect fish, invertebrates, and vegetation that inhabit these areas. To address this concern, the MegaTransect Deposition Effects Study evaluated the condition and sensitivity of the AT corridor with respect to acidic deposition, and defined air pollution thresholds (critical and target loads) and recovery rates. Findings indicate that additional S emission

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

Energy Technology Data Exchange (ETDEWEB)

Chen, C.-T.; Gajek, M.; Raoux, S. [IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Casu, E. A. [IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Politecnico di Torino, Turin 10129 (Italy)

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.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

Science.gov (United States)

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

2013-07-01

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.

Phenolic acids as bioindicators of fly ash deposit revegetation.

Science.gov (United States)

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.

High frequency and large deposition of acid fog on high elevation forest.

Science.gov (United States)

Igawa, Manabu; Matsumura, Ko; Okochi, Hiroshi

2002-01-01

We have collected and analyzed fogwater on the mountainside of Mt. Oyama (1252 m) in the Tanzawa Mountains of Japan and observed the fog event frequency from the base of the mountain with a video camera. The fog event frequency increased with elevation and was observed to be present 46% of the year at the summit. The water deposition via throughfall increased with elevation because of the increase in fogwater interception and was about twice that via rain at the summit, where the air pollutant deposition via throughfall was several times that via rainwater. The dry deposition and the deposition via fogwater were dominant factors in the total ion deposition at high elevation sites. In a fog event, nitric acid, the major acid component on the mountain, is formed during the transport of the air mass from the base of the mountain along the mountainside, where gases including nitric acid deposit and are scavenged by fogwater. Therefore, high acidity caused by nitric acid and relatively low ion strength are observed in the fogwater at high elevation sites.

Expanding atmospheric acid deposition in China from the 1990s to the 2010s

Science.gov (United States)

Yu, Haili; Wang, Qiufeng

2017-04-01

Atmospheric acid deposition is considered a global environmental issue. China has been experiencing serious acid deposition, which is anticipated to be more serious with the country's economic development and increasing consumption of fossil fuels in recent decades. By collecting nationwide data on pH and concentrations of sulfate (SO42-) and nitrate (NO3-) in precipitation between 1980 and 2014 in China, we explored the spatiotemporal variations of precipitation acid deposition (bulk deposition) and their influencing factors. Our results showed that average precipitation pH values were 4.86 and 4.84 in the 1990s and 2010s, respectively. This suggests that precipitation acid deposition in China has not seriously changes. Average SO42- deposition declined from 30.73 to 28.61 kg S ha-1 yr-1 but average NO3- deposition increased from 4.02 to 6.79 kg N ha-1 yr-1. Specifically, the area of severe precipitation acid deposition in southern China has shrunk to some extent as a result of decreasing pollutant emissions, whereas the area of moderate precipitation acid deposition has expanded in northern China, associated with rapid industrial and transportation development. Significant positive correlations have been found between precipitation acid deposition, energy consumption, and rainfall. Our findings provide a comprehensive evaluation of the spatiotemporal dynamics of precipitation acid deposition in China over past three decades, and confirm the idea that strategies implemented to save energy and reduce pollutant emissions in China have been effective in alleviating precipitation acid deposition. These findings might be used to demonstrate how developing countries could achieve economic development and environmental protection through the implementation of advanced technologies to reduce pollutant emissions.

Development of atmospheric acid deposition in China from the 1990s to the 2010s

International Nuclear Information System (INIS)

Yu, Haili; He, Nianpeng; Wang, Qiufeng; Zhu, Jianxing; Gao, Yang; Zhang, Yunhai; Jia, Yanlong; Yu, Guirui

2017-01-01

Atmospheric acid deposition is a global environmental issue. China has been experiencing serious acid deposition, which is anticipated to become more severe with the country's economic development and increasing consumption of fossil fuels in recent decades. We explored the spatiotemporal variations of acid deposition (wet acid deposition) and its influencing factors by collecting nationwide data on pH and concentrations of sulfate (SO 4 2− ) and nitrate (NO 3 − ) in precipitation between 1980 and 2014 in China. Our results showed that average precipitation pH values were 4.59 and 4.70 in the 1990s and 2010s, respectively, suggesting that precipitation acid deposition in China has not seriously worsened. Average SO 4 2− deposition declined from 40.54 to 34.87 kg S ha −1 yr −1 but average NO 3 − deposition increased from 4.44 to 7.73 kg N ha −1 yr −1 . Specifically, the area of severe precipitation acid deposition in southern China has shrunk to some extent as a result of controlling the pollutant emissions; but the area of moderate precipitation acid deposition has expanded in northern China, associated with rapid industrial and transportation development. Furthermore, we found significant positive correlations between precipitation acid deposition, energy consumption, and rainfall. Our findings provide a relatively comprehensive evaluation of the spatiotemporal dynamics of precipitation acid deposition in China over past three decades, and confirm the idea that strategies implemented to save energy and control pollutant emissions in China have been effective in alleviating precipitation acid deposition. These findings might be used to demonstrate how developing countries could achieve economic development and environmental protection through the implementation of advanced technologies to reduce pollutant emissions. - Highlights: • Explore spatial and temporal dynamics of wet acid deposition during three decades in China. • Acid

Laser damage resistance of hafnia thin films deposited by electron beam deposition, reactive low voltage ion plating, and dual ion beam sputtering

International Nuclear Information System (INIS)

Gallais, Laurent; Capoulade, Jeremie; Natoli, Jean-Yves; Commandre, Mireille; Cathelinaud, Michel; Koc, Cian; Lequime, Michel

2008-01-01

A comparative study is made of the laser damage resistance of hafnia coatings deposited on fused silica substrates with different technologies: electron beam deposition (from Hf or HfO2 starting material), reactive low voltage ion plating, and dual ion beam sputtering.The laser damage thresholds of these coatings are determined at 1064 and 355 nm using a nanosecond pulsed YAG laser and a one-on-one test procedure. The results are associated with a complete characterization of the samples: refractive index n measured by spectrophotometry, extinction coefficient k measured by photothermal deflection, and roughness measured by atomic force microscopy

Acid deposition and water use efficiency in Appalachian forests

Science.gov (United States)

Malcomb, J.

2017-12-01

Multiple studies have reported increases in forest water use efficiency in recent decades, but the drivers of these trends remain uncertain. While acid deposition has profoundly altered the biogeochemistry of Appalachian forests in the past century, its impacts on forest water use efficiency have been largely overlooked. Plant ecophysiology literature suggests that plants up-regulate transpiration in response to soil nutrient limitation in order to maintain sufficient mass flow of nutrients. To test the impacts of acid deposition on forest eco-hydrology in central Appalachia, we integrated dendrochronological techniques, including tree ring δ13C analysis, with catchment water balance data from the Fernow Experimental Forest in West Virginia. Tree cores from four species were collected in Fernow Watershed 3, which has received experimental ammonium sulfate additions since 1989, and Watershed 7, an adjacent control catchment. Initial results suggest that acidification treatments have not significantly influenced tree productivity compared to a control watershed, but the effect varies by species, with tulip poplar showing greatest sensitivity to acidification. Climatic water balance, defined as the difference between growing season precipitation and evapotranspiration, is significantly related to annual tree ring growth, suggesting that climate may be driving tree growth trends in chronically acidified Appalachian forests. Tree ring 13C analysis from Fernow cores is underway and these data will be integrated with catchment hydrology data from five other sites in central Appalachia and the U.S. Northeast, representing a range of forest types, soil base saturations, and acid deposition histories. This work will advance understanding of how climate and acid deposition interact to influence forest productivity and water use efficiency, and improve our ability to model carbon and water cycling in forested ecosystems impacted by acid deposition.

Assessment of folic acid and DNA damage in cleft lip and cleft palate

Directory of Open Access Journals (Sweden)

Sivakumar Brooklyin

2014-03-01

Full Text Available Studies have identified the risk factors like folic acid deficiency during gestational period, family history for orofacial clefts, drugs like antiepileptic, vitamin A. But, the data regarding the folic acid status in children with cleft lip/palate is hardly evaluated in depth. Here, an assessment of folic acid and DNA damage were carried out in children with orofacial anomalies. Folic acid level and DNA damage were evaluated by folic acid assay (direct chemiluminescent technology and single cell gel electrophoresis or comet assay method respectively. The mean value of plasma folic acid by direct chemiluminescent technology was 6.5±3.6 nmol/L and the normal value in children ranges from 11.3 to 47.6 nmol/L. The amount of damaged DNA, measured as the tail length of the comet in cases, was 19.4±8.9 ?m and the mean percentage of DNA in tail was 16.5±3.7. Folic acid deficiency could be the reason for DNA damage.

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

Science.gov (United States)

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.

Essential fatty acid-rich diets protect against striatal oxidative damage induced by quinolinic acid in rats.

Science.gov (United States)

Morales-Martínez, Adriana; Sánchez-Mendoza, Alicia; Martínez-Lazcano, Juan Carlos; Pineda-Farías, Jorge Baruch; Montes, Sergio; El-Hafidi, Mohammed; Martínez-Gopar, Pablo Eliasib; Tristán-López, Luis; Pérez-Neri, Iván; Zamorano-Carrillo, Absalom; Castro, Nelly; Ríos, Camilo; Pérez-Severiano, Francisca

2017-09-01

Essential fatty acids have an important effect on oxidative stress-related diseases. The Huntington's disease (HD) is a hereditary neurologic disorder in which oxidative stress caused by free radicals is an important damage mechanism. The HD experimental model induced by quinolinic acid (QUIN) has been widely used to evaluate therapeutic effects of antioxidant compounds. The aim of this study was to test whether the fatty acid content in olive- or fish-oil-rich diet prevents against QUIN-related oxidative damage in rats. Rats were fed during 20 days with an olive- or a fish-oil-rich diet (15% w/w). Posterior to diet period, rats were striatally microinjected with QUIN (240 nmol/µl) or saline solution. Then, we evaluated the neurological damage, oxidative status, and gamma isoform of the peroxisome proliferator-activated receptor (PPARγ) expression. Results showed that fatty acid-rich diet, mainly by fish oil, reduced circling behavior, prevented the fall in GABA levels, increased PPARγ expression, and prevented oxidative damage in striatal tissue. In addition none of the enriched diets exerted changes neither on triglycerides or cholesterol blood levels, nor or hepatic function. This study suggests that olive- and fish-oil-rich diets exert neuroprotective effects.

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

Science.gov (United States)

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

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...

Do uric acid deposits in zooxanthellae function as eye-spots?

Directory of Open Access Journals (Sweden)

Hiroshi Yamashita

2009-07-01

Full Text Available 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.

Do uric acid deposits in zooxanthellae function as eye-spots?

Science.gov (United States)

Yamashita, Hiroshi; Kobiyama, Atsushi; Koike, Kazuhiko

2009-07-17

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.

Radiation induced crystallinity damage in poly(L-lactic acid)

CERN Document Server

Kantoglu, O

2002-01-01

The radiation-induced crystallinity damage in poly(L-lactic acid) (PLLA) in the presence of air and in vacuum, is studied. From the heat of fusion enthalpy values of gamma irradiated samples, some changes on the thermal properties were determined. To identify these changes, first the glass transition temperature (T sub g) of L-lactic acid polymers irradiated to various doses in air and vacuum have been investigated and it is found that it is independent of irradiation atmosphere and dose. The fraction of damaged units of PLLA per unit of absorbed energy has been measured. For this purpose, SAXS and differential scanning calorimetry methods were used, and the radiation yield of number of damaged units (G(-u)) is found to be 0.74 and 0.58 for PLLA samples irradiated in vacuum and air, respectively.

Phenolic acids as bioindicators of fly ash deposit revegetation

Energy Technology Data Exchange (ETDEWEB)

L. Djurdjevic; M. Mitrovic; P. Pavlovic; G. Gajic; O. Kostic [Institute for Biological Research ' Sinisa Stankovic,' Belgrade (Serbia and Montenegro). Department of Ecology

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.

Effects of acid rain and sulfur dioxide on marble dissolution

Science.gov (United States)

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.

Handbook of methods for acid-deposition studies. Laboratory analyses for soil chemistry

International Nuclear Information System (INIS)

Blume, L.J.; Schumacher, P.W.; Schaffer, K.A.; Cappo, K.A.; Papp, M.L.

1990-09-01

The handbook describes methods used to process and analyze soil samples. It is intended as a guidance document for groups involved in acid deposition monitoring activities similar to those implemented by the Aquatic Effects Research Program of the National Acid Precipitation Assessment Program. These methods were developed for use in the Direct/Delayed Response Project, a component project of the Aquatic Effects Research Program within the Office of Ecological Processes and Effects Research. The program addresses the following issues relating to the effects of acid deposition on aquatic ecosystems: The extent and magnitude of past change; The change to be expected in the future under various deposition scenarios; The maximum rates of deposition below which further change is not expected; and The rate of change or recovery of aquatic ecosystems if deposition rates are decreased. Chemical and physical parameters were measured during the Direct/Delayed Response Project and are described in the document

[Current situation and impact factors of acid deposition in main cites of Shandong Province].

Science.gov (United States)

Jia, Hong-yu; Zhang, Qiao-xian; Deng, Hong-bing; Zhao, Jing-zhu; Mu, Jin-bo; Zhang, De-zhi

2006-12-01

Based on the monitoring data for years in Shandong Province, current situation of acid rain in every city was assessed, and the temporal distribution of the dry, wet and total sulfur deposition in Jinan and Qingdao were studied. The results showed that Qingdao which had the largest precipitation acidity was the single city whose annul average precipitation pH was below 5. 60. The precipitation acidities in the main cities of Shandong Province were in a descent tendency. The total sulfur desposition in Jinan and Qingdao was basically stable or in a descent tendency, but also reached 10 t/(km(2)x a) or so. Among the total sulfur deposition flux, the dry deposition of sulfur had the greater contribution, and the contribution of SO2 dry deposition was higher than that of SO42- dry deposition. By analyzing the relation between the precipitation acidity and the SO2 discharge intensity, soil acidity and meteorological condition, the impact factors of acid precipitation in the cities of Shandong Province were revealed.

Theory of acid deposition and its application to the dew-point meter

Energy Technology Data Exchange (ETDEWEB)

Land, T.

1977-06-01

The theory of convective mass transfer is used to calculate the rate of deposition of sulphuric acid on cooled surfaces in boiler flues. The mass deposited per unit area per second is ah/c (p/sub Ag/ - p/sub As/) where h is the coefficient of convective heat transfer, c is the specific heat of the gas and a is a factor having a value of about 1.9; p/sub Ag/ and p/sub As/ are the partial pressures of sulphuric acid in the bulk of the gas and in saturated gas at the temperature of the surface. Values of p/sub A/ are tabulated against dew-point temperature and water vapour content. The theory explains how fog formation in the gas reduces the rate of acid deposition within a certain band of temperature between the acid dew-point and the water dew-point. The rate of deposition on a probe is shown to depend on the local mass flow as well as on the acid content. By contrast the dew-point depends only on the acid content. The sensitivity of the dew-point meter to changes in acid content is not very high but it is adequate for the control of combustion. A continuously recording dew-point meter is being successfully used on industrial boilers.

Characterization of the acidic cold seep emplaced jarositic Golden Deposit, NWT, Canada, as an analogue for jarosite deposition on Mars

Science.gov (United States)

Battler, Melissa M.; Osinski, Gordon R.; Lim, Darlene S. S.; Davila, Alfonso F.; Michel, Frederick A.; Craig, Michael A.; Izawa, Matthew R. M.; Leoni, Lisa; Slater, Gregory F.; Fairén, Alberto G.; Preston, Louisa J.; Banerjee, Neil R.

2013-06-01

Surficial deposits of the OH-bearing iron sulfate mineral jarosite have been observed in several places on Mars, such as Meridiani Planum and Mawrth Vallis. The specific depositional conditions and mechanisms are not known, but by comparing martian sites to analogous locations on Earth, the conditions of formation and, thus, the martian depositional paleoenvironments may be postulated. Located in a cold semi-arid desert ˜100 km east of Norman Wells, Northwest Territories, Canada, the Golden Deposit (GD) is visible from the air as a brilliant golden-yellow patch of unvegetated soil, approximately 140 m × 50 m. The GD is underlain by permafrost and consists of yellow sediment, which is precipitating from seeps of acidic, iron-bearing groundwater. On the surface, the GD appears as a patchwork of raised polygons, with acidic waters flowing from seeps in troughs between polygonal islands. Although UV-Vis-NIR spectral analysis detects only jarosite, mineralogy, as determined by X-ray diffraction and inductively coupled plasma emission spectrometry, is predominantly natrojarosite and jarosite, with hydronium jarosite, goethite, quartz, clays, and small amounts of hematite. Water pH varies significantly over short distances depending on proximity to acid seeps, from 2.3 directly above seeps, to 5.7 several m downstream from seeps within the deposit, and up to 6.5 in ponds proximal to the deposit. Visual observations of microbial filament communities and phospholipid fatty acid analyses confirm that the GD is capable of supporting life for at least part of the year. Jarosite-bearing sediments extend beneath vegetation up to 70 m out from the deposit and are mixed with plant debris and minerals presumably weathered from bedrock and glacial till. This site is of particular interest because mineralogy (natrojarosite, jarosite, hematite, and goethite) and environmental conditions (permafrost and arid conditions) at the time of deposition are conceivably analogous to jarosite

Potential research money available from the Acid Deposition Program and Alberta Environment

International Nuclear Information System (INIS)

Primus, C.L.

1992-01-01

It is exceedingly difficult to demonstrate definitive long-term changes in animal health as a result of acid-forming emissions from sour gas wells. A summary is presented of current research in Alberta, followed by the potential for research funding by the Alberta Government/Industry Acid Deposition Program (ADRP). The Alberta Environment research budget consists of four programs in addition to the ADRP: acid deposition effects research in the Athabasca oil sands; western and northern Canada long-range transport of air pollutants; departmental monitoring; and inhalation toxicology and animal health. Animal health research, although a component of the acid deposition issue, is beyond the mandate of Alberta Environment, and the ADRP members committee does not forsee becoming involved in the long-term and complex research required to address the effects of acid-forming emissions on livestock. Funds for additional animal health research must come from other government departments and agencies whose mandate covers this area

Antagonist effects of veratric acid against UVB-induced cell damages.

Science.gov (United States)

Shin, Seoung Woo; Jung, Eunsun; Kim, Seungbeom; Lee, Kyung-Eun; Youm, Jong-Kyung; Park, Deokhoon

2013-05-10

Ultraviolet (UV) radiation induces DNA damage, oxidative stress, and inflammatory processes in human epidermis, resulting in inflammation, photoaging, and photocarcinogenesis. Adequate protection of skin against the harmful effect of UV irradiation is essential. In recent years naturally occurring herbal compounds such as phenolic acids, flavonoids, and high molecular weight polyphenols have gained considerable attention as beneficial protective agents. The simple phenolic veratric acid (VA, 3,4-dimethoxybenzoic acid) is one of the major benzoic acid derivatives from vegetables and fruits and it also occurs naturally in medicinal mushrooms which have been reported to have anti-inflammatory and anti-oxidant activities. However, it has rarely been applied in skin care. This study, therefore, aimed to explore the possible roles of veratric acid in protection against UVB-induced damage in HaCaT cells. Results showed that veratric acid can attenuate cyclobutane pyrimidine dimers (CPDs) formation, glutathione (GSH) depletion and apoptosis induced by UVB. Furthermore, veratric acid had inhibitory effects on the UVB-induced release of the inflammatory mediators such as IL-6 and prostaglandin-E2. We also confirmed the safety and clinical efficacy of veratric acid on human skin. Overall, results demonstrated significant benefits of veratric acid on the protection of keratinocyte against UVB-induced injuries and suggested its potential use in skin photoprotection.

Acidic precipitation. Volume 3: Sources, deposition, and canopy interactions. Advances in environmental science

Energy Technology Data Exchange (ETDEWEB)

Lindberg, S.E.; Page, A.L.; Norton, S.A. (eds.)

1990-01-01

As has been the case with many environmental issues of the twentieth century, acidic precipitation has its origin in emissions to the atmosphere of numerous compounds from both natural and man-made sources. This volume emphasizes the atmospheric aspects of acidic precipitation and all that this term has come to include (e.g. toxic gases such as ozone, trace metals, aluminum, and oxides of nitrogen). It progresses from emissions of the precursors of acidic precipitation to their eventual deposition on environmental surfaces. The chapters describe the sources of acidic and basic airborne substances, their interactions in the atmosphere and with rain droplets, and their reactions with other airborne constituents such as aluminum and other metals. Also discussed are the use of metals as tracers of sources of the precursors of acidic precipitation and as tracers of historical deposition rates, the processes controlling the removal of airborne material as dry deposition and deposition interactions with the forest canopy, and past and future trends in atmospheric emissions and options for their abatement.

Acidic deposition: State of science and technology. Report 14. Methods for projecting future changes in surface water acid-base chemistry. Final report

International Nuclear Information System (INIS)

Thornton, K.W.; Marmorek, D.; Ryan, P.F.; Heltcher, K.; Robinson, D.

1990-09-01

The objectives of the report are to: critically evaluate methods for projecting future effects of acidic deposition on surface water acid-base chemistry; review and evaluate techniques and procedures for analyzing projection uncertainty; review procedures for estimating regional lake and stream population attributes; review the U.S. Environmental Protection Agency (EPA) Direct/Delayed Response Project (DDRP) methodology for projecting the effects of acidic deposition on future changes in surface water acid-base chemistry; and present the models, uncertainty estimators, population estimators, and proposed approach selected to project the effects of acidic deposition on future changes in surface water acid-base chemistry in the NAPAP 1990 Integrated Assessment and discuss the selection rationale

Antagonist Effects of Veratric Acid against UVB-Induced Cell Damages

Directory of Open Access Journals (Sweden)

Deokhoon Park

2013-05-01

Full Text Available Ultraviolet (UV radiation induces DNA damage, oxidative stress, and inflammatory processes in human epidermis, resulting in inflammation, photoaging, and photocarcinogenesis. Adequate protection of skin against the harmful effect of UV irradiation is essential. In recent years naturally occurring herbal compounds such as phenolic acids, flavonoids, and high molecular weight polyphenols have gained considerable attention as beneficial protective agents. The simple phenolic veratric acid (VA, 3,4-dimethoxybenzoic acid is one of the major benzoic acid derivatives from vegetables and fruits and it also occurs naturally in medicinal mushrooms which have been reported to have anti-inflammatory and anti-oxidant activities. However, it has rarely been applied in skin care. This study, therefore, aimed to explore the possible roles of veratric acid in protection against UVB-induced damage in HaCaT cells. Results showed that veratric acid can attenuate cyclobutane pyrimidine dimers (CPDs formation, glutathione (GSH depletion and apoptosis induced by UVB. Furthermore, veratric acid had inhibitory effects on the UVB-induced release of the inflammatory mediators such as IL-6 and prostaglandin-E2. We also confirmed the safety and clinical efficacy of veratric acid on human skin. Overall, results demonstrated significant benefits of veratric acid on the protection of keratinocyte against UVB-induced injuries and suggested its potential use in skin photoprotection.

Acid deposition and assessment of its critical load for the environmental health of waterbodies in a subtropical watershed, China

Science.gov (United States)

Jia, Junjie; Gao, Yang

2017-12-01

Atmospheric acidic deposition in subtropical watersheds poses an environmental risk of causing acidification of aquatic ecosystems. In this study, we evaluated the frequency of acid deposition in a subtropical forest ecosystem and the associated critical loads of acidity for a sensitive aquatic ecosystem. We found that out of 132 rainfall events, 33(25%) were acidic rainfall occurrences. Estimated wet acid deposition (2282.78 eq·ha-1·yr-1), consistent with SO42- and NH4+ deposition, was high in spring and summer and low in autumn and winter. Waterbodies surrounded by mixed wood and citrus orchard experience severe acidification, mostly from S deposition because acidic deposition exceeds the corresponding critical loads of acidity. Modifications that take acid rain deposition into consideration are needed for land-use and agricultural management strategies to improve the environmental health of waterbodies in subtropical watersheds.

Absorption characteristics of Kupravas deposit clays modified by phosphoric acid

International Nuclear Information System (INIS)

Ruplis, A.; Mezinskis, G.; Chaghuri, M.

1998-01-01

Literature data suggested that clays may be used as sorbents for waste water treatment. The surface and sorption properties of minerals changes due to the influence of acid rains. The process of recession of clay properties has been modeled in laboratory by treatment of clays with mineral acids at higher temperature that in natural conditions. The present paper is devoted to the study of influence of phosphoric acid on the sorption properties of Kupravas deposit clays. Natural clay samples and samples treated with phosphoric acid were characterized by means of x-ray diffraction an differential thermal analysis (DTA) methods These methods were used also to identify the sample of Lebanese clays. X-ray diffraction analysis data show that the samples of clays from the deposit of Kuprava contain illite and kaolinite while sample of Lebanese clay contains quartz, calcite, and montmorillonite. DTA results show characteristic features of Kuprava clays described in reference with DTA of Lebanese clay clearly demonstrate the presence of large quantity of calcite

Bismuth nanowire growth under low deposition rate and its ohmic contact free of interface damage

Directory of Open Access Journals (Sweden)

Ye Tian

2012-03-01

Full Text Available High quality bismuth (Bi nanowire and its ohmic contact free of interface damage are quite desired for its research and application. In this paper, we propose one new way to prepare high-quality single crystal Bi nanowires at a low deposition rate, by magnetron sputtering method without the assistance of template or catalyst. The slow deposition growth mechanism of Bi nanowire is successfully explained by an anisotropic corner crossing effect, which is very different from existing explanations. A novel approach free of interface damage to ohmic contact of Bi nanowire is proposed and its good electrical conductivity is confirmed by I-V characteristic measurement. Our method provides a quick and convenient way to produce high-quality Bi nanowires and construct ohmic contact for desirable devices.

Effects of acid deposition on ecosystems: Advances in the state of the science

Science.gov (United States)

Burns, Douglas A.; Fenn, Mark E.; Baron, Jill S.

2011-01-01

Chapter 2 focused on the environmental results of the ARP, presenting data from national monitoring networks on SO2 and NOx emissions, air quality, atmospheric deposition, surface water chemistry, and visibility. This chapter expands on this information by examining the most recent research into how ecosystems respond to acid deposition, especially the processes that control the recovery of ecosystems as acid deposition decreases. In Chapter 2, two general trends were discussed regarding the current recovery status of affected ecosystems: (1) these ecosystems are trending generally towards recovery, but improvements in ecosystem condition shown by surface water chemistry monitoring data thus far have been less than the improvements in deposition; and (2) ecosystem impacts and trends vary widely by geographic region, but the evidence of improvement is strongest and most evident in the Northeast. These trends are not uniform across the United States, however, and in some regions (e.g., central Appalachian Mountain region), trends in improved water quality are generally not evident. Despite the strong link in many areas between reduced emissions and reduced acidity of atmospheric deposition, the link is less clear between reduced acidity and recovery of the biological communities that live in aquatic and terrestrial ecosystems that have experienced deleterious effects from acid deposition. The recovery of these communities is proceeding at a slower pace than, for example, the improvements in stream and lake ANC would indicate. The goal of this chapter is to synthesize the science in a weightof-evidence manner to provide policy makers with tangible evidence and likely causative factors regarding ecosystem status and recovery patterns to date. This chapter serves as an update to the 2005 NAPAP RTC (NSTC, 2005), with an emphasis on scientific studies and monitoring since 2003, which was the last year for consideration of research results in the 2005 report. Several

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

Directory of Open Access Journals (Sweden)

María del Carmen Martinez

2015-01-01

Full Text Available 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.

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

Energy Technology Data Exchange (ETDEWEB)

Harris, R.E.; McKay, D.M. [Cleansorb Limited, Surrey (United Kingdom); Moses, V. [King`s College, London (United Kingdom)

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.

Acidic deposition in California: findings from a program of monitoring and effects research

Energy Technology Data Exchange (ETDEWEB)

Takemoto, B.K.; Croes, B.E.; Brown, S.M.; Motallebi, N.; Westerdahl, F.D.; Margolis, H.G.; Cahill, B.T.; Mueller, M.D.; Holmes, J.R. [California Environmental Protection Agency, Sacramento, CA (United States). Research Division

1995-12-01

California`s 14-year, 25 million dollar acidic deposition program has studied the causes and effects of acidic air pollutants. In contrast to the eastern United States where sulfur-derived (S-derived) by-products from coal combustion dominate precipitation chemistry, nitrogen-derived (N-derived) acids predominate in wet and dry deposition in California. Adverse effects on the human lung have not been observed after short-term exposures to acidity, but extended exposures to ambient acidity may pose a chronic risk. No irreversible, adverse effects on surface waters in the Sierra Nevada mountain range or to the state`s forests have been found due to extent acidic inputs. The longer-term outlook for forests is less certain because the impacts observed elsewhere occurred after decades of S and N deposition, but at lower ambient ozone levels. Ozone is the major air pollutant stressor for forests, but atmospheric N has the potential to cause adverse changes in soil nutrient cycling. Impacts on man-made materials in southern California (e.g. galvanized steel) were found to be minor. While California does not have an ambient air quality standard for acidic air pollutants, emission of precursors have declined since the 1960s due to changes in industrial practices, improvements in technology and adoption of control measures for ozone. Lowering emission from motor vehicles will be emphasized to prevent future increases in N deposition. 67 refs., 4 figs., 2 tabs.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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

Acid atmospheric deposition in a forested mountain catchment

Czech Academy of Sciences Publication Activity Database

Křeček, J.; Palán, L.; Stuchlík, Evžen

2017-01-01

Roč. 10, č. 4 (2017), s. 680-686 ISSN 1971-7458 Institutional support: RVO:60077344 Keywords : mountain water shed * spruce forests * acid atmospheric deposition * water resources recharge Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 1.623, year: 2016

Damage and recovery of skin barrier function after glycolic acid chemical peeling and crystal microdermabrasion.

Science.gov (United States)

Song, Ji Youn; Kang, Hyun A; Kim, Mi-Yeon; Park, Young Min; Kim, Hyung Ok

2004-03-01

Superficial chemical peeling and microdermabrasion have become increasingly popular methods for producing facial rejuvenation. However, there are few studies reporting the skin barrier function changes after these procedures. To evaluate objectively the degree of damage visually and the time needed for the skin barrier function to recover after glycolic acid peeling and aluminum oxide crystal microdermabrasion using noninvasive bioengineering methods. Superficial chemical peeling using 30%, 50%, and 70% glycolic acid and aluminum oxide crystal microdermabrasion were used on the volar forearm of 13 healthy women. The skin response was measured by a visual observation and using an evaporimeter, corneometer, and colorimeter before and after peeling at set time intervals. Both glycolic acid peeling and aluminum oxide crystal microdermabrasion induced significant damage to the skin barrier function immediately after the procedure, and the degree of damage was less severe after the aluminum oxide crystal microdermabrasion compared with glycolic acid peeling. The damaged skin barrier function had recovered within 24 hours after both procedures. The degree of erythema induction was less severe after the aluminum oxide crystal microdermabrasion compared with the glycolic acid peeling procedure. The degree of erythema induced after the glycolic acid peeling procedure was not proportional to the peeling solution concentration used. The erythema subsided within 1 day after the aluminum oxide crystal microdermabrasion procedure and within 4 days after the glycolic acid peeling procedure. These results suggest that the skin barrier function is damaged after the glycolic acid peeling and aluminum oxide crystal microdermabrasion procedure but recovers within 1 to 4 days. Therefore, repeating the superficial peeling procedure at 2-week intervals will allow sufficient time for the damaged skin to recover its barrier function.

Urban acid deposition. Results from the GMADS network, 1990

Energy Technology Data Exchange (ETDEWEB)

Conlan, D.E.; Longhurst, J.W.S.; Gee, D.R.; Hare, S.E.

1991-07-01

This fourth annual data report of the Greater Manchester Acid Deposition Survey (GMADS) gives results from the urban precipitation chemistry network across Greater Manchester and Warrington for 1990. Full analytical methods are described along with precision and accuracy of the methods used. The spatial variability of precipitation chemistry and deposition over this urban region was investigated using a network of twenty collectors. Concentrations of non marine sulphate, ammonium, calcium and hydrogen, and nitrogen dioxide gas concentrations all show significant spatial variability. The spatial variability of the deposition rates of non marine sulphate, nitrate, ammonium, hydrogen and calcium were significant. 40 refs., 13 figs., 9 tabs., 1 app.

Acidic deposition: State of science and technology. Report 10. Watershed and lake processes affecting surface-water acid-base chemistry. Final report

International Nuclear Information System (INIS)

Turner, R.S.; Cook, R.B.; Miegroet, H.V.; Johnson, D.W.; Elwood, J.W.

1990-09-01

The acid-base chemistry of surface waters is governed by the amount and chemistry of deposition and by the biogeochemical reactions that generate acidity or acid neutralizing capacity (ANC) along the hydrologic pathways that water follows through watersheds to streams and lakes. The amount of precipitation and it chemical loading depend on the area's climate and physiography, on it proximity to natural or industrial gaseous or particulate sources, and on local or regional air movements. Vegetation interacts with the atmosphere to enhance both wet and dry deposition of chemicals to a greater or lesser extent, depending on vegetation type. Vegetation naturally acidifies the environment in humid regions through processes of excess base cation uptake and generation of organic acids associated with many biological processes. Natural acid production and atmospheric deposition of acidic materials drive the acidification process. The lake or stream NAC represents a balance between the acidity-and ANC-generating processes that occur along different flow paths in the watershed and the relative importance of each flow path

Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols

KAUST Repository

Kravitz, Ben

2009-07-28

We used a general circulation model of Earth\\'s climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide and analyzed the resulting deposition of sulfate. When sulfur dioxide is injected into the tropical or Arctic stratosphere, the main additional surface deposition of sulfate occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions. We used critical load studies to determine the effects of this increase in sulfate deposition on terrestrial ecosystems by assuming the upper limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, neither the maximum point value of sulfate deposition of approximately 1.5 mEq m−2 a−1 nor the largest additional deposition that would result from geoengineering of approximately 0.05 mEq m−2 a−1 is enough to negatively impact most ecosystems.

Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols

KAUST Repository

Kravitz, Ben; Robock, Alan; Oman, Luke; Stenchikov, Georgiy L.; Marquardt, Allison B.

2009-01-01

We used a general circulation model of Earth's climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide and analyzed the resulting deposition of sulfate. When sulfur dioxide is injected into the tropical or Arctic stratosphere, the main additional surface deposition of sulfate occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions. We used critical load studies to determine the effects of this increase in sulfate deposition on terrestrial ecosystems by assuming the upper limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, neither the maximum point value of sulfate deposition of approximately 1.5 mEq m−2 a−1 nor the largest additional deposition that would result from geoengineering of approximately 0.05 mEq m−2 a−1 is enough to negatively impact most ecosystems.

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

Energy Technology Data Exchange (ETDEWEB)

Frei, B. (Department of Nutrition, Harvard School of Public Health, Boston, MA (Unites States))

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.

Antagonist Effects of Veratric Acid against UVB-Induced Cell Damages

OpenAIRE

Deokhoon Park; Jong-Kyung Youm; Kyung-Eun Lee; Seungbeom Kim; Eunsun Jung; Seoung Woo Shin

2013-01-01

Ultraviolet (UV) radiation induces DNA damage, oxidative stress, and inflammatory processes in human epidermis, resulting in inflammation, photoaging, and photocarcinogenesis. Adequate protection of skin against the harmful effect of UV irradiation is essential. In recent years naturally occurring herbal compounds such as phenolic acids, flavonoids, and high molecular weight polyphenols have gained considerable attention as beneficial protective agents. The simple phenolic veratric acid (VA, ...

Survival of brown trout during spring flood in DOC-rich streams in northern Sweden: the effect of present acid deposition and modelled pre-industrial water quality

International Nuclear Information System (INIS)

Laudon, Hjalmar; Poleo, Antonio B.S.; Voellestad, Leif Asbjoern; Bishop, Kevin

2005-01-01

Mortality and physiological responses in brown trout (Salmo trutta) were studied during spring snow melt in six streams in northern Sweden that differed in concentrations of dissolved organic carbon (DOC) and pH declines. Data from these streams were used to create an empirical model for predicting fish responses (mortality and physiological disturbances) in DOC-rich streams using readily accessible water chemistry parameters. The results suggest that fish in these systems can tolerate higher acidity and inorganic aluminium levels than fish in low DOC streams. But even with the relatively low contemporary deposition load, anthropogenic deposition can cause fish mortality in the most acid-sensitive surface waters in northern Sweden during spring flood. However, the results suggests that it is only in streams with high levels of organically complexed aluminium in combination with a natural pH decline to below 5.0 during the spring where current sulphur deposition can cause irreversible damage to brown trout in the region. This study support earlier studies suggesting that DOC has an ameliorating effect on physiological disturbances in humic waters but the study also shows that surviving fish recover physiologically when the water quality returns to less toxic conditions following a toxic high flow period. The physiological response under natural, pre-industrial conditions was also estimated. - High levels of complexed aluminum, at pH levels below 5.0, predisposes brown trout to sulfur-caused damage in the spring

Survival of brown trout during spring flood in DOC-rich streams in northern Sweden: the effect of present acid deposition and modelled pre-industrial water quality

Energy Technology Data Exchange (ETDEWEB)

Laudon, Hjalmar [Department of Forest Ecology, Swedish University of Agricultural Sciences, SE-901 83 Umeaa (Sweden)]. E-mail: hjalmar.laudon@sek.slu.se; Poleo, Antonio B.S. [Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway); Voellestad, Leif Asbjoern [Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway); Bishop, Kevin [Department of Environmental Assessment, Swedish University of Agricultural Sciences, SE-750 07 Uppsala (Sweden)

2005-05-01

Mortality and physiological responses in brown trout (Salmo trutta) were studied during spring snow melt in six streams in northern Sweden that differed in concentrations of dissolved organic carbon (DOC) and pH declines. Data from these streams were used to create an empirical model for predicting fish responses (mortality and physiological disturbances) in DOC-rich streams using readily accessible water chemistry parameters. The results suggest that fish in these systems can tolerate higher acidity and inorganic aluminium levels than fish in low DOC streams. But even with the relatively low contemporary deposition load, anthropogenic deposition can cause fish mortality in the most acid-sensitive surface waters in northern Sweden during spring flood. However, the results suggests that it is only in streams with high levels of organically complexed aluminium in combination with a natural pH decline to below 5.0 during the spring where current sulphur deposition can cause irreversible damage to brown trout in the region. This study support earlier studies suggesting that DOC has an ameliorating effect on physiological disturbances in humic waters but the study also shows that surviving fish recover physiologically when the water quality returns to less toxic conditions following a toxic high flow period. The physiological response under natural, pre-industrial conditions was also estimated. - High levels of complexed aluminum, at pH levels below 5.0, predisposes brown trout to sulfur-caused damage in the spring.

The Contribution from Shipping Emissions to Air Quality and Acid Deposition in Europe

International Nuclear Information System (INIS)

Derwent, Richard G.; Stevenson, David S.; Doherty, Ruth M.; Cofala, Janusz; Mechler, Reinhard; Amann, Markus; Dentener, Frank J.

2005-01-01

A global three-dimensional Lagrangian chemistry-transport model STOCHEM is used to describe the European regional acid deposition and ozone air quality impacts along the Atlantic Ocean seaboard of Europe, from the SO 2 , NO x , VOCs and CO emissions from international shipping under conditions appropriate to the year 2000. Model-derived total sulfur deposition from international shipping reaches over 200 mg S m-2 yr-1 over the southwestern approaches to the British Isles and Brittany. The contribution from international shipping to surface ozone concentrations during the summertime, peaks at about 6 ppb over Ireland, Brittany and Portugal. Shipping emissions act as an external influence on acid deposition and ozone air quality within Europe and may require control actions in the future if strict deposition and air quality targets are to be met

Deposition of LDH on plasma treated polylactic acid to reduce water permeability

KAUST Repository

Bugatti, Valeria

2013-04-01

A simple and scalable deposition process was developed to prepare polylactic acid (PLA) coatings with enhanced water barrier properties for food packaging applications. This method based on electrostatic interactions between the positively charged layers of layered double hydroxides (LDHs) modified with ionic liquids (ILs) and the negatively charged plasma treated polylactic acid leads to homogeneous, stable, and highly durable coatings. Deposition of the LDH coatings increases the surface hydrophobicity of the neat PLA, which results to a decrease in water permeability by about 35%. © 2013 Elsevier Inc.

Acidic deposition: State of science and technology. Report 9. Current status of surface-water acid-base chemistry. Final report

International Nuclear Information System (INIS)

Baker, L.A.; Kaufmann, P.R.; Brakke, D.F.; Herlihy, A.T.; Eilers, J.M.

1990-09-01

The report is based largely upon the National Surface Water Survey (NSWS), augmented by numerous smaller state and university surveys and many detailed watershed studies. In describing the current status of surface waters, the authors go far beyond the description of population statistics, although some of this is necessary, and direct their attention to the interpretation of these data. They address the question of the sources of acidity to surface waters in order to determine the relative importance of acidic deposition compared with other sources, such as naturally produced organic acids and acid mine drainage. They also examine in some detail what they call 'high interest' populations-the specific groups of lakes and streams most likely to be impacted by acidic deposition. The authors then turn to the general question of uncertainty, and finally examine low alkalinity surface waters in several other parts of the world to develop further inferences about the acid-base status of surface waters in the United States

Influence of containing of asphaltenes and naphthenic acids over organic deposition inhibitor performance

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Geiza E.; Mansur, Claudia R.E.; Pires, Renata V.; Passos, Leonardo B.; Lucas, Elizabete F. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas; Alvares, Dellyo R.S.; Gonzalez, Gaspar [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2004-07-01

Organic deposition is a serious problem confronted by the petroleum industry in Brazil and worldwide. Among the main petroleum components that may cause deposition problems are waxes and asphaltenes. This work aims at evaluating the influence of petroleum fractions (asphaltenes and naphthenic acids) on the organic deposition phenomenon as well as on organic deposition inhibitors performance. The influence of the organic fractions was evaluated by their ability to change wax crystals, to lower the pour point and to alter the initial wax appearance temperature. The efficiency of the additives was tested by pour point measurements. The results show that asphaltenes seem to act as organic deposition inhibitors, while naphthenic acids do not significantly change the system. Moreover, employing both of them produces no synergic effect. Among polymeric inhibitors, all of the chemically modified EVA copolymer presented better results than the non-modified commercial EVA copolymer. The best result was observed for EVA28C{sub 16}. (author)

Serum uric acid levels contribute to new renal damage in systemic lupus erythematosus patients.

Science.gov (United States)

Reátegui-Sokolova, C; Ugarte-Gil, Manuel F; Gamboa-Cárdenas, Rocío V; Zevallos, Francisco; Cucho-Venegas, Jorge M; Alfaro-Lozano, José L; Medina, Mariela; Rodriguez-Bellido, Zoila; Pastor-Asurza, Cesar A; Alarcón, Graciela S; Perich-Campos, Risto A

2017-04-01

This study aims to determine whether uric acid levels contribute to new renal damage in systemic lupus erythematosus (SLE) patients. This prospective study was conducted in consecutive patients seen since 2012. Patients had a baseline visit and follow-up visits every 6 months. Patients with ≥2 visits were included; those with end-stage renal disease (regardless of dialysis or transplantation) were excluded. Renal damage was ascertained using the SLICC/ACR damage index (SDI). Univariable and multivariable Cox-regression models were performed to determine the risk of new renal damage. Uric acid was included as a continuous and dichotomous (per receiving operating characteristic curve) variable. Multivariable models were adjusted for age at diagnosis, disease duration, socioeconomic status, SLEDAI, SDI, serum creatinine, baseline use of prednisone, antimalarials, and immunosuppressive drugs. One hundred and eighty-six patients were evaluated; their mean (SD) age at diagnosis was 36.8 (13.7) years; nearly all patients were mestizo. Disease duration was 7.7 (6.8) years. Follow-up time was 2.3 (1.1) years. The SLEDAI was 5.2 (4.3) and the SDI 0.8 (1.1). Uric acid levels were 4.5 (1.3) mg/dl. During follow-up, 16 (8.6%) patients developed at least one new point in the renal domain of the SDI. In multivariable analyses, uric acid levels (continuous and dichotomous) at baseline predicted the development of new renal damage (HR 3.21 (1.39-7.42), p 0.006; HR 18.28 (2.80-119.48), p 0.002; respectively). Higher uric acid levels contribute to the development of new renal damage in SLE patients independent of other well-known risk factors for such occurrence.

Terbium fluorescence as a sensitive, inexpensive probe for UV-induced damage in nucleic acids

International Nuclear Information System (INIS)

El-Yazbi, Amira F.; Loppnow, Glen R.

2013-01-01

Graphical abstract: -- Highlights: •Simple, inexpensive, mix-and-read assay for positive detection of DNA damage. •Recognition of undamaged DNA via hybridization to a hairpin probe. •Terbium(III) fluorescence reports the amount of damage by binding to ssDNA. •Tb/hairpin is a highly selective and sensitive fluorescent probe for DNA damage. -- Abstract: Much effort has been focused on developing methods for detecting damaged nucleic acids. However, almost all of the proposed methods consist of multi-step procedures, are limited, require expensive instruments, or suffer from a high level of interferences. In this paper, we present a novel simple, inexpensive, mix-and-read assay that is generally applicable to nucleic acid damage and uses the enhanced luminescence due to energy transfer from nucleic acids to terbium(III) (Tb 3+ ). Single-stranded oligonucleotides greatly enhance the Tb 3+ emission, but duplex DNA does not. With the use of a DNA hairpin probe complementary to the oligonucleotide of interest, the Tb 3+ /hairpin probe is applied to detect ultraviolet (UV)-induced DNA damage. The hairpin probe hybridizes only with the undamaged DNA. However, the damaged DNA remains single-stranded and enhances the intrinsic fluorescence of Tb 3+ , producing a detectable signal directly proportional to the amount of DNA damage. This allows the Tb 3+ /hairpin probe to be used for sensitive quantification of UV-induced DNA damage. The Tb 3+ /hairpin probe showed superior selectivity to DNA damage compared to conventional molecular beacons probes (MBs) and its sensitivity is more than 2.5 times higher than MBs with a limit of detection of 4.36 ± 1.2 nM. In addition, this probe is easier to synthesize and more than eight times cheaper than MBs, which makes its use recommended for high-throughput, quantitative analysis of DNA damage

Measurements of dry-deposition parameters for the California acid-deposition monitoring program. Final report

International Nuclear Information System (INIS)

Watson, J.G.; Chow, J.C.; Egami, R.T.; Bowen, J.L.; Frazier, C.A.

1991-06-01

The State of California monitors the concentrations of acidic gases and particles at 10 sites throughout the state. Seven sites represent urban areas (South Coast Air Basin - three sites, San Francisco Bay Area, Bakersfield, Santa Barbara, and Sacramento) and three represent forested areas (Sequoia National Park, Yosemite National Park, and Gasquet). Several sites are collocated with monitoring instruments for other air quality and forest response networks. Continuous monitors for the dry deposition network collect hourly average values for ozone, wind speed, wind direction, atmospheric stability, temperature, dew point, time of wetness, and solar radiation. A newly-designed gas/particle sampler collects daytime (6 a.m. to 6 p.m.) and nighttime (6 p.m. to 6 a.m.) samples every sixth day for sulfur dioxide, ammonia, nitrogen dioxide, and nitric acid. Particles are collected on the same day/night schedule in PM(10) and PM(2.5) size ranges, and are analyzed for mass, sulfate, nitrate, chloride, ammonium, sodium, magnesium, potassium, and calcium ions. The sampling schedule follows the regulatory schedule adopted by the EPA and ARB for suspended particulate matter. Wet deposition data are collected at or nearby the dry deposition stations. The first year of the monitoring program included installation of the network, training of technicians, acquisition and validation of data, and transfer of the sampling and analysis technology to Air Resources Board operating divisions. Data have been validated and stored for the period May, 1988 through September, 1989

In Barrett's esophagus patients and Barrett's cell lines, ursodeoxycholic acid increases antioxidant expression and prevents DNA damage by bile acids.

Science.gov (United States)

Peng, Sui; Huo, Xiaofang; Rezaei, Davood; Zhang, Qiuyang; Zhang, Xi; Yu, Chunhua; Asanuma, Kiyotaka; Cheng, Edaire; Pham, Thai H; Wang, David H; Chen, Minhu; Souza, Rhonda F; Spechler, Stuart Jon

2014-07-15

Hydrophobic bile acids like deoxycholic acid (DCA), which cause oxidative DNA damage and activate NF-κB in Barrett's metaplasia, might contribute to carcinogenesis in Barrett's esophagus. We have explored mechanisms whereby ursodeoxycholic acid (UDCA, a hydrophilic bile acid) protects against DCA-induced injury in vivo in patients and in vitro using nonneoplastic, telomerase-immortalized Barrett's cell lines. We took biopsies of Barrett's esophagus from 21 patients before and after esophageal perfusion with DCA (250 μM) at baseline and after 8 wk of oral UDCA treatment. DNA damage was assessed by phospho-H2AX expression, neutral CometAssay, and phospho-H2AX nuclear foci formation. Quantitative PCR was performed for antioxidants including catalase and GPX1. Nrf2, catalase, and GPX1 were knocked down with siRNAs. Reporter assays were performed using a plasmid construct containing antioxidant responsive element. In patients, baseline esophageal perfusion with DCA significantly increased phospho-H2AX and phospho-p65 in Barrett's metaplasia. Oral UDCA increased GPX1 and catalase levels in Barrett's metaplasia and prevented DCA perfusion from inducing DNA damage and NF-κB activation. In cells, DCA-induced DNA damage and NF-κB activation was prevented by 24-h pretreatment with UDCA, but not by mixing UDCA with DCA. UDCA activated Nrf2 signaling to increase GPX1 and catalase expression, and protective effects of UDCA pretreatment were blocked by siRNA knockdown of these antioxidants. UDCA increases expression of antioxidants that prevent toxic bile acids from causing DNA damage and NF-κB activation in Barrett's metaplasia. Elucidation of this molecular pathway for UDCA protection provides rationale for clinical trials on UDCA for chemoprevention in Barrett's esophagus. Copyright © 2014 the American Physiological Society.

Bioactivation of carboxylic acid compounds by UDP-Glucuronosyltransferases to DNA-damaging intermediates: role of glycoxidation and oxidative stress in genotoxicity.

Science.gov (United States)

Sallustio, Benedetta C; Degraaf, Yvette C; Weekley, Josephine S; Burcham, Philip C

2006-05-01

Nonenzymatic modification of proteins by acyl glucuronides is well documented; however, little is known about their potential to damage DNA. We have previously reported that clofibric acid undergoes glucuronidation-dependent bioactivation to DNA-damaging species in cultured mouse hepatocytes. The aim of this study was to investigate the mechanisms underlying such DNA damage, and to screen chemically diverse carboxylic acid drugs for their DNA-damaging potential in glucuronidation proficient murine hepatocytes. Cells were incubated with each aglycone for 18 h, followed by assessment of compound cytotoxicity using the MTT assay and evaluation of DNA damage using the Comet assay. Relative cytotoxic potencies were ketoprofen > diclofenac, benoxaprofen, nafenopin > gemfibrozil, probenecid > bezafibrate > clofibric acid. At a noncytotoxic (0.1 mM) concentration, only benoxaprofen, nafenopin, clofibric acid, and probenecid significantly increased Comet moments (P Clofibric acid and probenecid exhibited the greatest DNA-damaging potency, producing significant DNA damage at 0.01 mM concentrations. The two drugs produced maximal increases in Comet moment of 4.51 x and 2.57 x control, respectively. The glucuronidation inhibitor borneol (1 mM) abolished the induction of DNA damage by 0.5 mM concentrations of clofibric acid and probenecid. In an in vitro cell-free system, clofibric acid glucuronide was 10 x more potent than glucuronic acid in causing DNA strand-nicking, although both compounds showed similar rates of autoxidation to generate hydroxyl radicals. In cultured hepatocytes, the glycation inhibitor, aminoguanidine, and the iron chelator, desferrioxamine mesylate, inhibited DNA damage by clofibric acid, whereas the free radical scavengers Trolox and butylated hydroxytoluene, and the superoxide dismutase mimetic bis-3,5-diisopropylsalicylate had no effect. In conclusion, clinically relevant concentrations of two structurally unrelated carboxylic acids, probenecid and

The impact of nitrogen deposition on acid grasslands in the Atlantic region of Europe

Energy Technology Data Exchange (ETDEWEB)

Stevens, Carly J., E-mail: c.j.stevens@open.ac.uk [Department of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Dupre, Cecilia [Institute of Ecology, FB 2, University of Bremen, Leobener Str., DE-28359 Bremen (Germany); Dorland, Edu [Ecology and Biodiversity Group, Department of Biology, Institute of Environmental Biology, Utrecht University, PO Box 80.058, 3508 TB Utrecht (Netherlands); Gaudnik, Cassandre [University of Bordeaux 1, UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Gowing, David J.G. [Department of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Bleeker, Albert [Department of Air Quality and Climate Change, Energy Research Centre of the Netherlands, PO Box 1, 1755 ZG Petten (Netherlands); Diekmann, Martin [Institute of Ecology, FB 2, University of Bremen, Leobener Str., DE-28359 Bremen (Germany); Alard, Didier [University of Bordeaux 1, UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Bobbink, Roland [B-WARE Research Centre, Radboud University, PO Box 9010, 6525 ED Nijmegen (Netherlands); Fowler, David [NERC Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB (United Kingdom); Corcket, Emmanuel [University of Bordeaux 1, UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Mountford, J. Owen [NERC Centre for Ecology and Hydrology, MacLean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Vandvik, Vigdis [Department of Biology, University of Bergen, Box 7800, N-5020 Bergen (Norway)

2011-10-15

A survey of 153 acid grasslands from the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is changing plant species composition and soil and plant-tissue chemistry. Across the deposition gradient (2-44 kg N ha{sup -1} yr{sup -1}) grass richness as a proportion of total species richness increased whereas forb richness decreased. Soil C:N ratio increased, but soil extractable nitrate and ammonium concentrations did not show any relationship with nitrogen deposition. The above-ground tissue nitrogen contents of three plant species were examined: Agrostis capillaris (grass), Galium saxatile (forb) and Rhytidiadelphus squarrosus (bryophyte). The tissue nitrogen content of neither vascular plant species showed any relationship with nitrogen deposition, but there was a weak positive relationship between R. squarrosus nitrogen content and nitrogen deposition. None of the species showed strong relationships between above-ground tissue N:P or C:N and nitrogen deposition, indicating that they are not good indicators of deposition rate. - Highlights: > N deposition is negatively correlated with forb richness as a proportion of species richness. > Soil C:N ratio increased with increasing N deposition. > Soil extractable nitrate and ammonium were not related to nitrogen deposition. > Plant-tissue N content was not a good indicator of N deposition. - Atmospheric nitrogen deposition affects soils, plant-tissue chemistry and plant species composition in acid grasslands in the Atlantic biogeographic region of Europe.

The impact of nitrogen deposition on acid grasslands in the Atlantic region of Europe

International Nuclear Information System (INIS)

Stevens, Carly J.; Dupre, Cecilia; Dorland, Edu; Gaudnik, Cassandre; Gowing, David J.G.; Bleeker, Albert; Diekmann, Martin; Alard, Didier; Bobbink, Roland; Fowler, David; Corcket, Emmanuel; Mountford, J. Owen; Vandvik, Vigdis

2011-01-01

A survey of 153 acid grasslands from the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is changing plant species composition and soil and plant-tissue chemistry. Across the deposition gradient (2-44 kg N ha -1 yr -1 ) grass richness as a proportion of total species richness increased whereas forb richness decreased. Soil C:N ratio increased, but soil extractable nitrate and ammonium concentrations did not show any relationship with nitrogen deposition. The above-ground tissue nitrogen contents of three plant species were examined: Agrostis capillaris (grass), Galium saxatile (forb) and Rhytidiadelphus squarrosus (bryophyte). The tissue nitrogen content of neither vascular plant species showed any relationship with nitrogen deposition, but there was a weak positive relationship between R. squarrosus nitrogen content and nitrogen deposition. None of the species showed strong relationships between above-ground tissue N:P or C:N and nitrogen deposition, indicating that they are not good indicators of deposition rate. - Highlights: → N deposition is negatively correlated with forb richness as a proportion of species richness. → Soil C:N ratio increased with increasing N deposition. → Soil extractable nitrate and ammonium were not related to nitrogen deposition. → Plant-tissue N content was not a good indicator of N deposition. - Atmospheric nitrogen deposition affects soils, plant-tissue chemistry and plant species composition in acid grasslands in the Atlantic biogeographic region of Europe.

Impact of acid atmosphere deposition on soils : field monitoring and aluminum chemistry

NARCIS (Netherlands)

Mulder, J.

1988-01-01

The effect of acid atmospheric deposition on concentrations and transfer of major solutes in acid, sandy soils was studied. Emphasis was given to mobilization and transport of potentially toxic aluminum. Data on solute concentrations and fluxes in meteoric water as well as soil solutions

Acid-deposition research program. Volume 2. Effects of acid-forming emissions on soil microorganisms and microbially-mediated processes

Energy Technology Data Exchange (ETDEWEB)

Visser, S.; Danielson, R.M.; Parr, J.F.

1987-02-01

The interactions of soil physical, chemical, and biological processes are ultimately expressed in a soil's fertility and its capacity for plant production. Consequently, much of the research conducted to date regarding the impact of acid-forming pollutants on soil properties has been geared towards possible effects on plant productivity. This trend continues in this paper where the effects of acidic deposition on microbial communities are reviewed in relation to potential impact on plant growth. The objectives of the review are to discuss: (1) The effects of acid-forming emissions (primarily S-containing pollutants) on microbial community structure with emphasis on qualitative and quantitative aspects; (2) The effects of acidic deposition on microbially mediated processes (i.e., community functions); (3) Acidification effects of pollutants on symbiotic and disease-causing microorganisms. The symbionts discussed include ectomycorrhizal fungi, vesicular-arbuscular mycorrhizal fungi, and N/sub 2/-fixing bacteria, particularly Rhizobium, while the disease-causing microorganisms will include those responsible for foliage, stem, and root diseases.

Intensified Vegetation Water Use due to Soil Calcium Leaching under Acid Deposition

Science.gov (United States)

Lanning, M.; Wang, L.; Scanlon, T. M.; Vadeboncoeur, M. A.; Adams, M. B.; Epstein, H. E.; Druckenbrod, D.

2017-12-01

Despite the important role vegetation plays in the global water cycle, the exact controls of vegetation water use, especially the role of soil biogeochemistry, remain elusive. Nitrate and sulfate deposition from fossil fuel burning has caused significant soil acidification, leading to the leaching of soil base cations. From a physiological perspective, plants require various soil cations as signaling and regulatory ions as well as integral parts of structural molecules; a depletion of soil cations can cause reduced productivity and abnormal responses to environmental change. A deficiency in calcium could also potentially prolong stomatal opening, leading to increased transpiration until enough calcium had been acquired to stimulate stomatal closure. Based on the plant physiology and the nature of acidic deposition, we hypothesize that depletion of the soil calcium supply, induced by acid deposition, would intensify vegetation water use at the watershed scale. We tested this hypothesis by analyzing a long-term and unique data set (1989-2012) of soil lysimeter data along with stream flow and evapotranspiration data at the Fernow Experimental Forest. We show that depletion of soil calcium by acid deposition can intensify vegetation water use ( 10% increase in evapotranspiration and depletion in soil water) for the first time. These results are critical to understanding future water availability, biogeochemical cycles, and surficial energy flux and may help reduce uncertainties in terrestrial biosphere models.

Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York

Science.gov (United States)

Sullivan, Timothy J.; Lawrence, Gregory B.; Bailey, Scott W.; McDonnell, Todd C.; McPherson, G.T.

2013-01-01

This study documents the effects of acidic deposition and soil acid-base chemistry on the growth, regeneration, and canopy condition of sugar maple (SM) trees in the Adirondack Mountains of New York. Sugar maple is the dominant canopy species throughout much of the northern hardwood forest in the State. A field study was conducted in 2009 in which 50 study plots within 20 small Adirondack watersheds were sampled and evaluated for soil acid-base chemistry and SM growth, canopy condition, and regeneration. Atmospheric sulfur (S) and nitrogen (N) deposition were estimated for each plot. Trees growing on soils with poor acid-base chemistry (low exchangeable calcium and % base saturation) that receive relatively high levels of atmospheric S and N deposition exhibited little to no SM seedling regeneration, decreased canopy condition, and short-to long-term growth declines compared with study plots having better soil condition and lower levels of atmospheric deposition. These results suggest that the ecosystem services provided by SM in the western and central Adirondack Mountain region, including aesthetic, cultural, and monetary values, are at risk from ongoing soil acidification caused in large part by acidic deposition.

Poly(aniline-co-m-aminobenzoic acid) deposited on poly(vinyl ...

Indian Academy of Sciences (India)

Abstract. In this work, we have deposited poly(aniline-co-m-aminobenzoic acid) on poly(vinyl alcohol) (PVA) by in situ ... along the polyaniline (PANI) chain results in self dop- ing of PANI and ..... The value of electrical conductivity is found to be ...

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

Energy Technology Data Exchange (ETDEWEB)

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)

Acid deposition: a select review 1852-1990. 2. Effects on materials and health; abatement strategies and programmes

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S.; Raper, D.W.; Lee, D.S.; Heath, B.A.; Conlan, B.; King, H.J. (Manchester Metropolitan University, Manchester (United Kingdom). Atmospheric Research and Information Centre)

1993-10-01

Part 2 of this review is concerned with the impact of acid deposits and their precursors on materials and human health, and with the control technologies and programmes introduced as a consequence of the environmental impacts of acid deposition. 269 refs., 8 figs., 8 tabs.

Effect of humic acid on the underpotential deposition-stripping voltammetry of copper in acetic acid soil extract solutions at mercaptoacetic acid-modified gold electrodes

Energy Technology Data Exchange (ETDEWEB)

Herzog, Gregoire; Beni, Valerio; Dillon, Patrick H.; Barry, Thomas; Arrigan, Damien W.M

2004-05-24

Electrochemical measurements were undertaken for the investigation of the underpotential deposition-stripping process of copper at bare and modified gold electrodes in 0.11 M acetic acid, the first fraction of the European Union's Bureau Communautaire de References (BCR) sequential extraction procedure for fractionating metals within soils and sediments. Gold electrodes modified with mercaptoacetic acid showed higher sensitivity for the detection of copper than bare gold electrodes, both in the absence and in the presence of humic acid in acetic acid solutions, using the underpotential deposition-stripping voltammetry (UPD-SV) method. In the presence of 50 mg l{sup -1} of humic acid, the mercaptoacetic acid modified electrode proved to be 1.5 times more sensitive than the bare gold electrode. The mercaptoacetic acid monolayer formed on the gold surface provided efficient protection against the adsorption of humic acid onto the gold electrode surface. Variation of the humic acid concentration in the solution showed little effect on the copper stripping signal at the modified electrode. UPD-SV at the modified electrode was applied to the analysis of soil extract samples. Linear correlation of the electrochemical results with atomic spectroscopic results yielded the straight-line equation y ({mu}g l{sup -1}) = 1.10x - 44 (ppb) (R=0.992, n=6), indicating good agreement between the two methods.

Influence of Humic Acid on the Transport and Deposition of Colloidal Silica under Different Hydrogeochemical Conditions

Directory of Open Access Journals (Sweden)

Jingjing Zhou

2016-12-01

Full Text Available The transport and deposition of colloids in aquifers plays an important role in managed aquifer recharge (MAR schemes. Here, the processes of colloidal silica transport and deposition were studied by displacing groundwater with recharge water. The results showed that significant amounts of colloidal silica transport occurred when native groundwater was displaced by HA solution. Solution contains varying conditions of ionic strength and ion valence. The presence of humic acid could affect the zeta potential and size of the colloidal silica, which led to obvious colloidal silica aggregation in the divalent ion solution. Humic acid increased colloidal silica transport by formation of non-adsorbing aqueous phase silica–HA complexes. The experimental and modeling results showed good agreement, indicating that the essential physics were accurately captured by the model. The deposition rates were less than 10−8 s−1 in deionized water and monovalent ion solution. Moreover, the addition of Ca2+ and increase of IS resulted in the deposition rates increasing by five orders of magnitude to 10−4 s−1. In all experiments, the deposition rates decreased in the presence of humic acid. Overall, the promotion of humic acid in colloidal silica was strongly associated with changes in water quality, indicating that they should receive greater attention during MAR.

A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?

Science.gov (United States)

Pannatier, Elisabeth Graf; Thimonier, Anne; Schmitt, Maria; Walthert, Lorenz; Waldner, Peter

2011-03-01

Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.

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

Energy Technology Data Exchange (ETDEWEB)

Baedecker, P.A.; Reddy, M.M.; Reimann, K.J.; Sciammarella, C.A. (US Geological Survey, Reston, VA (USA))

1992-06-01

Test briquettes and slabs of freshly quarried limestone and marble have been exposed to the environment to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulphur dioxide, and nitrogen oxides on stone erosion. Erosion due to grain loss did not seem to be influenced by rainfall acidity, but may be influenced by dry deposition of sulphur dioxide between rainfall events. Chemical analyses of the run-off solutions suggest that around 30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulphur dioxide and nitric acid between rain events. The remaining 70% of erosion by dissolution is accounted for by the solubility of carbonate stone in 'clean' rain. 17 refs., 4 figs., 7 tabs.

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

International Nuclear Information System (INIS)

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

1995-01-01

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

[Nickel exposure to A549 cell damage and L-ascorbic acid interference effect].

Science.gov (United States)

Fu, Yao; Wang, Yue; Dan, Han; Zhang, Lin; Ma, Wenhan; Pan, Yulin; Wu, Yonghui

2015-05-01

Studying different concentrations of nickel smelting smoke subjects of human lung adenocarcinoma cells (A549) carcinogenic effects, discusses the influence of L-ascorbic acid protection. The A549 cells were divided into experimental and L-ascorbic acid in the intervention group. Plus exposure group concentration of nickel refining dusts were formulated 0.00, 6.25, 12.50, 25.00, 50.00, 100.00 µg/ml suspension, the intervention group on the basis of the added exposure group containing L-ascorbic acid (100 mmol/L), contact 24 h. Detection of cell viability by MTT assay. When the test substance concentration select 0.00, 25.00, 50.00, 100.00 µg/ml experiment for internal Flou-3 fluorescent probe to detect cell Ca²⁺ concentration, within DCFH-DA detect intracellular reactive oxygen (ROS) content, real-time quantitative PCR (real time, in the RT-PCR) was used to detect cell HIF-1α gene expression. With the increase of concentration, subjects increased cell growth inhibition rate, intracellular Ca²⁺ concentration increases, ROS content increased, HIF-1α gene expression increased, differences were statistically significant (P nickel exposure damage to cells. With subjects following exposure to nickel concentration increased, its effect on A549 cell damage increases, L-ascorbic acid cell damage caused by nickel has certain protective effect.

Dietary Berries and Ellagic Acid Prevent Oxidative DNA Damage and Modulate Expression of DNA Repair Genes

Directory of Open Access Journals (Sweden)

Ramesh C. Gupta

2008-03-01

Full Text Available DNA damage is a pre-requisite for the initiation of cancer and agents that reduce this damage are useful in cancer prevention. In this study, we evaluated the ability of whole berries and berry phytochemical, ellagic acid to reduce endogenous oxidative DNA damage. Ellagic acid was selected based on > 95% inhibition of 8-oxodeoxyguosine (8-oxodG and other unidentified oxidative DNA adducts induced by 4-hydroxy-17B;-estradiol and CuCl2 in vitro. Inhibition of the latter occurred at lower concentrations (10 u(microM than that for 8-oxodG (100 u(microM. In the in vivo study, female CD-1 mice (n=6 were fed either a control diet or diet supplemented with ellagic acid (400 ppm and dehydrated berries (5% w/w with varying ellagic acid contents -- blueberry (low, strawberry (medium and red raspberry (high, for 3 weeks. Blueberry and strawberry diets showed moderate reductions in endogenous DNA adducts (25%. However, both red raspberry and ellagic acid diets showed a significant reduction of 59% (p < 0.001 and 48% (p < 0.01, respectively. Both diets also resulted in a 3-8 fold over-expression of genes involved in DNA repair such as xeroderma pigmentosum group A complementing protein (XPA, DNA excision repair protein (ERCC5 and DNA ligase III (DNL3. These results suggest that red raspberry and ellagic acid reduce endogenous oxidative DNA damage by mechanisms which may involve increase in DNA repair.

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

Science.gov (United States)

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

Effects of branched-chain amino acids supplementation on both plasma amino acids concentration and muscle energetics changes resulting from muscle damage: A randomized placebo controlled trial.

Science.gov (United States)

Fouré, Alexandre; Nosaka, Kazunori; Gastaldi, Marguerite; Mattei, Jean-Pierre; Boudinet, Hélène; Guye, Maxime; Vilmen, Christophe; Le Fur, Yann; Bendahan, David; Gondin, Julien

2016-02-01

Branched-chain amino acids promote muscle-protein synthesis, reduce protein oxidation and have positive effects on mitochondrial biogenesis and reactive oxygen species scavenging. The purpose of the study was to determine the potential benefits of branched-chain amino acids supplementation on changes in force capacities, plasma amino acids concentration and muscle metabolic alterations after exercise-induced muscle damage. (31)P magnetic resonance spectroscopy and biochemical analyses were used to follow the changes after such damage. Twenty six young healthy men were randomly assigned to supplemented branched-chain amino acids or placebo group. Knee extensors maximal voluntary isometric force was assessed before and on four days following exercise-induced muscle damage. Concentrations in phosphocreatine [PCr], inorganic phosphate [Pi] and pH were measured during a standardized rest-exercise-recovery protocol before, two (D2) and four (D4) days after exercise-induced muscle damage. No significant difference between groups was found for changes in maximal voluntary isometric force (-24% at D2 and -21% at D4). Plasma alanine concentration significantly increased immediately after exercise-induced muscle damage (+25%) in both groups while concentrations in glycine, histidine, phenylalanine and tyrosine decreased. No difference between groups was found in the increased resting [Pi] (+42% at D2 and +34% at D4), decreased resting pH (-0.04 at D2 and -0.03 at D4) and the slower PCr recovery rate (-18% at D2 and -24% at D4). The damaged muscle was not able to get benefits out of the increased plasma branched-chain amino acids availability to attenuate changes in indirect markers of muscle damage and muscle metabolic alterations following exercise-induced muscle damage. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Effects of acid and alkaline based surface preparations on spray deposited cerium based conversion coatings on Al 2024-T3

Energy Technology Data Exchange (ETDEWEB)

Pinc, W. [Department of Materials Science Engineering, Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65409 (United States)], E-mail: wrphw5@mst.edu; Geng, S.; O' Keefe, M.; Fahrenholtz, W.; O' Keefe, T. [Department of Materials Science Engineering, Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65409 (United States)

2009-01-15

Cerium based conversion coatings were spray deposited on Al 2024-T3 and characterized to determine the effect of surface preparation on the deposition rate and surface morphology. It was found that activation of the panel using a 1-wt.% sulfuric acid solution increased the coating deposition rate compared to alkaline cleaning alone. Analysis of the surface morphology of the coatings showed that the coatings deposited on the acid treated panels exhibited fewer visible cracks compared to coatings on alkaline cleaned panels. Auger electron spectroscopy depth profiling showed that the acid activation decreased the thickness of the aluminum oxide layer and the concentration of magnesium on the surface of the panels compared to the alkaline treatment. Additionally, acid activation increased the copper concentration at the surface of the aluminum substrate. Based on the results, the acid based surface treatment appeared to expose copper rich intermetallics, thus increasing the number of cathodic sites on the surface, which led to an overall increase in the deposition rate.

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

Directory of Open Access Journals (Sweden)

Karen S. Bishop

2015-01-01

Full Text Available 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.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

Science.gov (United States)

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.

Differences in functional traits between invasive and native Amaranthus species under simulated acid deposition with a gradient of pH levels

Science.gov (United States)

Wang, Congyan; Wu, Bingde; Jiang, Kun; Zhou, Jiawei

2018-05-01

Co-occurring invasive plant species (invaders hereafter) and natives receive similar or even the same environmental selection pressures. Thus, the differences in functional traits between natives and invaders have become widely recognized as a major driving force of the success of plant invasion. Meanwhile, increasing amounts of acid are deposited into ecosystems. Thus, it is important to elucidate the potential effects of acid deposition on the functional traits of invaders in order to better understand the potential mechanisms for the successful invasion. This study aims to address the differences in functional traits between native red amaranth (Amaranthus tricolor L.; amaranth hereafter) and invasive redroot pigweed (A. retroflexus L.; pigweed hereafter) under simulated acid deposition with a gradient of pH levels. Pigweed was significantly taller than amaranth under most treatments. The greater height of pigweed can lead to greater competitive ability for resource acquisition, particularly for sunlight. Leaf shape index of pigweed was also significantly greater than that of amaranth under all treatments. The greater leaf shape index of pigweed can enhance the efficiency of resource capture (especially sunlight capture) via adjustments to leaf shape and size. Thus, the greater height and leaf shape index of pigweed can significantly enhance its competitive ability, especially under acid deposition. Acid deposition of pH 5.6 significantly increased amaranth leaf width in the co-cultivation due to added nutrients. The pH 4.5 acid deposition treatment significantly increased the specific leaf area of amaranth in the monoculture compared with the pH 5.6 acid deposition treatment and the control. The main mechanism explaining this pattern may be due to acid deposition mediating a hormesis effect on plants, promoting plant growth. The values of the relative competition intensity between amaranth and pigweed for most functional traits were lower than zero under most

Deposition of LDH on plasma treated polylactic acid to reduce water permeability

KAUST Repository

Bugatti, Valeria; Livi, Sebastien; Hayrapetyan, Suren; Wang, Yue; Estevez, Luis; Vittoria, Vittoria; Giannelis, Emmanuel P.

2013-01-01

A simple and scalable deposition process was developed to prepare polylactic acid (PLA) coatings with enhanced water barrier properties for food packaging applications. This method based on electrostatic interactions between the positively charged

Effect of Time and Deposition Method on Quality of Phosphonic Acid Modifier Self-Assembled Monolayers on Indium Zinc Oxide

Energy Technology Data Exchange (ETDEWEB)

Sang, Lingzi; Knesting, Kristina M.; Bulusu, Anuradha; Sigdel, Ajaya K.; Giordano, Anthony J.; Marder, Seth R.; Berry, Joseph J.; Graham, Samuel; Ginger, David S.; Pemberton, Jeanne E.

2016-12-15

Phosphonic acid (PA) self-assembled monolayers (SAMs) are utilized at critical interfaces between transparent conductive oxides (TCO) and organic active layers in organic photovoltaic devices (OPVs). The effects of PA deposition method and time on the formation of close-packed, high-quality monolayers is investigated here for SAMs fabricated by solution deposition, micro-contact printing, and spray coating. The solution deposition isotherm for pentafluorinated benzylphosphonic acid (F5BnPA) on indium-doped zinc oxide (IZO) is studied using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS) at room temperature as a model PA/IZO system. Fast surface adsorption occurs within the first min; however, well-oriented high-quality SAMs are reached only after -48 h, presumably through a continual process of molecular adsorption/desorption and monolayer filling accompanied by molecular reorientation. Two other rapid, soak-free deposition techniques, micro-contact printing and spray coating, are also explored. SAM quality is compared for deposition of phenyl phosphonic acid (PPA), F13-octylphosphonic acid (F13OPA), and pentafluorinated benzyl phosphonic acid (F5BnPA) by solution deposition, micro-contact printing and spray coating using PM-IRRAS. In contrast to micro-contact printing and spray coating techniques, 48-168 h solution deposition at both room temperature and 70 degrees C result in contamination- and surface etch-free close-packed monolayers with good reproducibility. SAMs fabricated by micro-contact printing and spray coating are much less well ordered.

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

Energy Technology Data Exchange (ETDEWEB)

Kuperman, R.G. [Argonne National Lab., IL (United States). Environmental Assessment Div.

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.

Acid rain and nitrogen deposition in a sub-tropical watershed (Piracicaba): ecosystem consequences

International Nuclear Information System (INIS)

Krusche, A.V.; Camargo, P.B. de; Cerri, C.E.; Ballester, M.V.; Lara, L.B.L.S.; Victoria, R.L.; Martinelli, L.A.

2003-01-01

Poorly buffered sandy soils may result in acidification problems for forests in this basin. - High levels of wet N and acidic deposition were measured in southeast Brazil. In this study we addressed the sensitivity of water bodies and soils to acidification and N deposition in the Piracicaba River basin (12,400 km 2 ). Average acid neutralization capacity (ANC) at 23 river sampling sites varied from 350 to 1800 μeq l -1 . Therefore, rivers and streams in the Piracicaba basin are well buffered, if the lower limit of 200 μeq l -1 is assumed as an indication of poorly buffered waters. ANC is increased by untreated wastewaters discarded into rivers and streams of the region. Average NO 3 concentrations varied from 20 to 70 μeq l -1 . At the most polluted river sites, NO 3 concentration is not highest, however, probably due to NO 3 reduction and denitrification. Most of the nitrogen in streams is also provided by wastewaters and not by wet deposition. The majority of the soils in the basin, however, are acidic with a low base cation content and high aluminum concentration. Therefore, soils in this basin are poorly buffered and, in areas of forest over sandy soils, acidification may be a problem

Effect of time and deposition method on quality of phosphonic acid modifier self-assembled monolayers on indium zinc oxide

Energy Technology Data Exchange (ETDEWEB)

Sang, Lingzi [Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721 (United States); Knesting, Kristina M. [Department of Chemistry, University of Washington, Seattle, WA 98195-1700 (United States); Bulusu, Anuradha [School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Sigdel, Ajaya K. [National Renewable Energy Laboratory, Golden, CO 80401 (United States); Giordano, Anthony J.; Marder, Seth R. [School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); Berry, Joseph J. [National Renewable Energy Laboratory, Golden, CO 80401 (United States); Graham, Samuel [School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Ginger, David S. [Department of Chemistry, University of Washington, Seattle, WA 98195-1700 (United States); Pemberton, Jeanne E., E-mail: pembertn@email.arizona.edu [Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721 (United States)

2016-12-15

Highlights: • Deposition of phosphonic acid monolayers on oxides from ethanol solutions occurs by rapid adsorption within 10 s with slower equilibration complete in 48 h. • The slower equilibration step involves molecular reorientation and vacancy filling on the oxide surface. • Soak-free deposition by spray coating and microcontact printing do not provide reproducible, fully-covered, uniform monolayers without substrate etching. • Adjustments to exposure time, substrate temperature, and solution/substrate contact efficiency are necessary to optimize soak-free methods. - Abstract: Phosphonic acid (PA) self-assembled monolayers (SAMs) are utilized at critical interfaces between transparent conductive oxides (TCO) and organic active layers in organic photovoltaic devices (OPVs). The effects of PA deposition method and time on the formation of close-packed, high-quality monolayers is investigated here for SAMs fabricated by solution deposition, micro-contact printing, and spray coating. The solution deposition isotherm for pentafluorinated benzylphosphonic acid (F{sub 5}BnPA) on indium-doped zinc oxide (IZO) is studied using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS) at room temperature as a model PA/IZO system. Fast surface adsorption occurs within the first min; however, well-oriented high-quality SAMs are reached only after ∼48 h, presumably through a continual process of molecular adsorption/desorption and monolayer filling accompanied by molecular reorientation. Two other rapid, soak-free deposition techniques, micro-contact printing and spray coating, are also explored. SAM quality is compared for deposition of phenyl phosphonic acid (PPA), F{sub 13}-octylphosphonic acid (F{sub 13}OPA), and pentafluorinated benzyl phosphonic acid (F{sub 5}BnPA) by solution deposition, micro-contact printing and spray coating using PM-IRRAS. In contrast to micro-contact printing and spray coating techniques, 48–168 h solution

Foliar loading and metabolic assimilation of dry deposited nitric acid air pollutants by trees

Science.gov (United States)

Pamela E. Padgett; Hillary Cook; Andrzej Bytnerowicz; Robert L. Heath

2009-01-01

Dry deposition of nitric acid vapor (HNO(3)) is a major contributor to eutrophication of natural ecosystems. Although soil fertilization by nitrogen deposition is considered to be the primary pathway for changes in plant nutrient status and shifts in ecological structure, the aerial portion of plants offer many times the surface area in which to...

Acidification and Acid Rain

Science.gov (United States)

Norton, S. A.; Veselã½, J.

2003-12-01

endangers the existing biota. Concerns about acid (or acidic) rain in its modern sense were publicized by the Swedish soil scientist Svante Odén (1968). He argued, initially in the Swedish press, that long-term increases in the atmospheric deposition of acid could lower the pH of surface waters, cause a decline in fish stocks, deplete soils of nutrients, and accelerate damage to materials. By the 1970s, acidification of surface waters was reported in many countries in Europe as well as in North America. The late twentieth-century rush to understand the impact of acid rain was driven by: (i) reports of damaged or threatened freshwater fisheries and (ii) damaged forests. Perhaps the earliest linkage between acidic surface water and damage to fish was made by Dahl (1921) in southern Norway. There, spring runoff was sufficiently acidic to kill trout. It was not until the 1970s that a strong link was established between depressed pH, mobilization of aluminum from soil, and fish status ( Schofield and Trojnar,1980). The relationship between acidification of soils and forest health started with hypotheses in the 1960s and has slowly developed. Acid rain enhances the availability of some nutrients (e.g., nitrogen), and may either enhance or diminish the availability of others (e.g., calcium, magnesium, potassium, and phosphorus). Damage to anthropogenic structures, human health, and visibility have also raised concerns. The history of these early developments was summarized by Cowling (1982). Since the 1970s, sulfur and nitrogen emissions to the atmosphere have been reduced by 50-85% and 0-30%, respectively, both in North America and Europe. The emission reductions have occurred as a consequence of knowledge gained and economic factors. While recovery of water quality is underway in some areas, problems of acidification persist, and are now complicated by the effects of climate change ( Schindler, 1997).

Sulfuric acid dissolution of the Chashma-Sang deposit's green clays

International Nuclear Information System (INIS)

Mirzoev, D.Kh.; Boboev, Kh.E.; Pulatov, M.S.; Mirsaidov, U.M.

2005-01-01

Present article is presenting the results of the roentgen phase, thermodynamic and physical-chemical investigations of the green clays of the Chashma-Sang deposit of the Republic of Tajikistan. It is presented mineralogical and chemical composition of the mineral raw materials. Kinetic of decomposition of the oxides of aluminum and iron on temperature, time and concentration of the sulfuric acid has been investigated

U(VI) speciation and reduction in acid chloride fluids in hydrothermal conditions: from transport to deposition of uranium in unconformity-related deposits

International Nuclear Information System (INIS)

Dargent, Maxime

2014-01-01

Circulations of acidic chloride brines in the earth's crust are associated with several types of uranium deposits, particularly unconformity-related uranium (URU) deposits. The spectacular high grade combined with the large tonnage of these deposits is at the origin of the key questions concerning the geological processes responsible for U transport and precipitation. The aim of this work is to performed experimental studies of U(VI) speciation and its reduction to U(IV) subsequently precipitation to uraninite under hydrothermal condition. About uranium transport, the study of U(VI) speciation in acidic brines at high temperature is performed by Raman and XAS spectroscopy, showing the coexistence of several uranyl chloride complexes UO 2 Cl n 2-n (n = 0 - 5). From this study, complexation constants are proposed. The strong capability of chloride to complex uranyl is at the origin of the transport of U(VI) at high concentration in acidic chloride brines. Concerning uranium precipitation, the reactivity of four potential reductants under conditions relevant for URU deposits genesis is investigated: H 2 , CH 4 , Fe(II) and the C-graphite. The kinetics of reduction reaction is measured as a function of temperature, salinity, pH and concentration of reductant. H 2 , CH 4 , and the C-graphite are very efficient while Fe(II) is not able to reduce U(VI) in same conditions. The duration of the mineralizing event is controlled by (i) the U concentration in the ore-forming fluids and (ii) by the generation of gaseous reductants, and not by the reduction kinetics. These mobile and efficient gaseous reductant could be at the origin of the extremely focus and massive character of ore in URU deposits. Finally, first partition coefficients uraninite/fluid of trace elements are obtained. This last part opens-up new perspectives on (i) REE signatures interpretation for a given type of uranium deposit (ii) and reconstruction of mineralizing fluids composition. (author) [fr

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

Science.gov (United States)

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.

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

Energy Technology Data Exchange (ETDEWEB)

Morgan, D.O.; Robinson, A.T.; Allen, D.A.; Picton, D.J.; Thornton, D.A. [TCS, Serco, Rutherford House, Olympus Park, Quedgeley, Gloucester, Gloucestershire GL2 4NF (United Kingdom); Shaw, S.E. [EDF Energy, Barnet Way, Barnwood, Gloucester GL4 3RS (United Kingdom)

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)

The response of soil solution chemistry in European forests to decreasing acid deposition.

Science.gov (United States)

Johnson, James; Graf Pannatier, Elisabeth; Carnicelli, Stefano; Cecchini, Guia; Clarke, Nicholas; Cools, Nathalie; Hansen, Karin; Meesenburg, Henning; Nieminen, Tiina M; Pihl-Karlsson, Gunilla; Titeux, Hugues; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Waldner, Peter; Jonard, Mathieu

2018-03-31

Acid deposition arising from sulphur (S) and nitrogen (N) emissions from fossil fuel combustion and agriculture has contributed to the acidification of terrestrial ecosystems in many regions globally. However, in Europe and North America, S deposition has greatly decreased in recent decades due to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Al tot ) and dissolved organic carbon were determined for the period 1995-2012. Plots with at least 10 years of observations from the ICP Forests monitoring network were used. Trends were assessed for the upper mineral soil (10-20 cm, 104 plots) and subsoil (40-80 cm, 162 plots). There was a large decrease in the concentration of sulphate (SO42-) in soil solution; over a 10-year period (2000-2010), SO42- decreased by 52% at 10-20 cm and 40% at 40-80 cm. Nitrate was unchanged at 10-20 cm but decreased at 40-80 cm. The decrease in acid anions was accompanied by a large and significant decrease in the concentration of the nutrient base cations: calcium, magnesium and potassium (Bc = Ca 2+  + Mg 2+  + K + ) and Al tot over the entire dataset. The response of soil solution acidity was nonuniform. At 10-20 cm, ANC increased in acid-sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40-80 cm, ANC remained unchanged in acid-sensitive soils (base saturation ≤20%, pHCaCl2 ≤ 4.5) and decreased in better-buffered soils (base saturation >20%, pHCaCl2 > 4.5). In addition, the molar ratio of Bc to Al tot either did not change or decreased. The results suggest a long-time lag between emission abatement and changes in soil solution acidity and underline the importance of long-term monitoring in evaluating ecosystem response to decreases in deposition. © 2018 John Wiley & Sons

Causes and avoidance of container damages by means of biocorrosion; Ursachen und Vermeidung von Behaelterschaeden durch Biokorrosion

Energy Technology Data Exchange (ETDEWEB)

Kuever, Jan [Amtliche Materialpruefungsanstalt Bremen (MPA), Bremen (Germany)

2011-07-01

The contribution under consideration deals with the causes and prevention of vessel damages due to corrosion by microorganisms (MIC, microbially induced corrosion) in the presence and absence of oxygen. In particular, the microbially induced corrosion by sulfate-reducing bacteria and the formation of sulfuric acid by microorganisms are described. Consequential damage caused by microorganisms are inactivation of filters and catalysts, degradation products from the fermentation process and deposits in the pipe system.

4.3. Decomposition of danburite concentrate of Ak-Arkar Deposit by nitric acid

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Kurbonov, A.S.; Mamatov, E.D.

2015-01-01

Present article is devoted to decomposition of danburite concentrate of Ak-Arkar Deposit by nitric acid. The influence of temperature on reaction process was studied. The dependence of extraction rate of oxides (B 2 O 3 , Al 2 O 3 , Fe 2 O 3 and Ca O) at nitric acid processing on temperature ranges from 25 to 95 deg C was defined. The dependence of extraction rate of oxides (B 2 O 3 , Al 2 O 3 , Fe 2 O 3 and Ca O) at nitric acid processing on process duration (5-60 minutes) was defined as well. The optimal conditions of decomposition of danburite concentrate by nitric acid were proposed.

Analysis of leachability for a sandstone uranium deposite with high acid consumption and sensitivities in Inner Mongolia

International Nuclear Information System (INIS)

Cheng Wei; Miao Aisheng; Li Jianhua; Zhou Lei; Chang Jingtao

2014-01-01

In-situ Leaching adaptability of a ground water oxidation zone type sandstone uranium deposit from Inner Mongolia is studied. The ore of the uranium deposit has high acid consumption and sensitivities in in-situ leaching. The leaching process with agent of CO_2 + O_2 and adjusting concentration of HCO_3"- can be suitable for the deposit. (authors)

Effect of N deposition on tree amino acid concentrations in two Sphagnum species

Energy Technology Data Exchange (ETDEWEB)

Karsisto, M; Kitunen, V [Finnish Forest Research Inst., Vantaa (Finland). Vantaa Research Centre; Jauhiainen, J [Joensuu Univ. (Finland). Dept. of Biology; Vasander, H [Helsinki Univ. (Finland). Dept. of Forest Ecology

1997-12-31

Nitrogen saturation of ecosystems occurs when the availability of nitrogen is not a growth limiting factor. This situation can be reached through fertilisation or by nitrogen deposition. Prolonged nitrogen saturation may overload the ecosystem and cause changes in the vigour and eventually in the composition of plant communities. But before this stage is reached, certain changes in nitrogen metabolism occur. These changes can be used as an early warning of nitrogen overload to ecosystems. A change in the amino acid pool of plants has been used as an indication of various kind of stress, including, temperature, nutrient imbalance, shading, drought or excess water. It has been postulated that such stresses have an effect on protein synthesis but not on the nitrogen uptake of plants. The result is an increase in the concentration of NH{sub 4}{sup +} ions in plant cells, which may have toxic effects to the plant and the processes that assimilate the free NH{sub 4}{sup +} ions. One of such process is the synthesis of amino acids, especially those containing a significant proportion of nitrogen, e.g. arginine, glutamine and asparagine. This study about the quantification of amino acids in two species of Sphagnum mosses is part of a larger study, the aim of which is to clarify how a number of Sphagnum species will cope with climatic change and nitrogen deposition. Sphagna are the most important members of the peat forming communities in the boreal zone. Sphagnum communities are formed by species specialised to grow in conditions of low nutrient availability, mainly provided via deposition. The present structure and composition of mire communities may be endangered due to elevated levels of nitrogen deposition that have persisted over the last few decades. (20 refs.)

Effect of N deposition on tree amino acid concentrations in two Sphagnum species

Energy Technology Data Exchange (ETDEWEB)

Karsisto, M.; Kitunen, V. [Finnish Forest Research Inst., Vantaa (Finland). Vantaa Research Centre; Jauhiainen, J. [Joensuu Univ. (Finland). Dept. of Biology; Vasander, H. [Helsinki Univ. (Finland). Dept. of Forest Ecology

1996-12-31

Nitrogen saturation of ecosystems occurs when the availability of nitrogen is not a growth limiting factor. This situation can be reached through fertilisation or by nitrogen deposition. Prolonged nitrogen saturation may overload the ecosystem and cause changes in the vigour and eventually in the composition of plant communities. But before this stage is reached, certain changes in nitrogen metabolism occur. These changes can be used as an early warning of nitrogen overload to ecosystems. A change in the amino acid pool of plants has been used as an indication of various kind of stress, including, temperature, nutrient imbalance, shading, drought or excess water. It has been postulated that such stresses have an effect on protein synthesis but not on the nitrogen uptake of plants. The result is an increase in the concentration of NH{sub 4}{sup +} ions in plant cells, which may have toxic effects to the plant and the processes that assimilate the free NH{sub 4}{sup +} ions. One of such process is the synthesis of amino acids, especially those containing a significant proportion of nitrogen, e.g. arginine, glutamine and asparagine. This study about the quantification of amino acids in two species of Sphagnum mosses is part of a larger study, the aim of which is to clarify how a number of Sphagnum species will cope with climatic change and nitrogen deposition. Sphagna are the most important members of the peat forming communities in the boreal zone. Sphagnum communities are formed by species specialised to grow in conditions of low nutrient availability, mainly provided via deposition. The present structure and composition of mire communities may be endangered due to elevated levels of nitrogen deposition that have persisted over the last few decades. (20 refs.)

Atgl gene deletion predisposes to proximal tubule damage by impairing the fatty acid metabolism

International Nuclear Information System (INIS)

Chen, Wen; Zhang, Qiong; Cheng, Shiwu; Huang, Jie; Diao, Ge; Han, Jian

2017-01-01

Fibrosis is the final common pathway of chronic kidney disease (CKD). Normal lipid metabolism is integral to renal physiology, and disturbances of renal lipid metabolism are increasingly being linked with CKD, including the fibrosis. Adipose triglyceride lipase (ATGL) is the rate-limiting enzyme of lipolysis. In the present study, we used Atgl −/− mice to investigate whether ATGL played a role in the regulation of proximal convoluted tubule (PCT) lipid metabolism and renal fibrosis development. ATGL deficiency led to lipid vacuolation of PCT and tubulointerstitial fibrosis, accompanied by massive albuminuria and decreased creatinine clearance rate (Ccr). In vitro experiments indicated that inhibition of ATGL in proximal tubular cell line HK-2 promoted intracellular lipid deposition, reactive oxygen species (ROS) accumulation and cell apoptosis. Both in vitro and in vivo experiments showed that ATGL inhibition decreased the renal peroxisome proliferator-activated receptorα(PPARα) expression, which implied the suppressed lipid metabolism. The antioxidant N-acetylcysteine (NAC) could partially reverse the effect of ROS accumulation and cell apoptosis, but could not restore the PPARαdecrease. These data raise the possibility that ATGL deficiency could impair the renal fatty acid metabolism though inhibiting PPARαexpression, which may lead to lipid deposition and cell apoptosis of PCT, and finally contribute to the renal fibrosis and dysfunction. - Highlights: • Atgl −/− mice develop tubulointerstitial damage and renal dysfunction. • ATGL deficiency results in lipid accumulation and apoptosis of proximal tubular cells. • ROS scavenger alleviates the ATGL-knockdown mediated lipid accumulation and apoptosis. • PPARαdown-regulation is the reason of ROS elevating in ATGL-knockdown HK-2 cells.

Enhancement of laser induced damage threshold of fused silica by acid etching combined with UV laser conditioning

International Nuclear Information System (INIS)

Chen Meng; Xiang Xia; Jiang Yong; Zu Xiaotao; Yuan Xiaodong; Zheng Wanguo; Wang Haijun; Li Xibin; Lu Haibing; Jiang Xiaodong; Wang Chengcheng

2010-01-01

Acid etching combined with UV laser conditioning is developed to enhance the laser induced damage threshold (LIDT) of fused silica. Firstly, the fused silica is etched for 1 ∼ 100 min with a buffered 1% HF solution. After acid etching, its transmittance, surface roughness and LIDT are measured. The results reveal that the fused silica has the highest LIDT and transmittance after etching for 10 min. Then UV laser (355 nm) conditioning is adopted to process the 10-min-etched fused silica. When the laser fluence is below 60% of fused silica's zero probability damage threshold, the LIDT increases gradually with the increase of laser conditioning fluence. However, the LIDT rapidly decreases to be lower than the threshold of the 10-min-etched fused silica when the conditioning fluence is up to 80% of the threshold. Proper acid etching and laser conditioning parameters will effectively enhance the laser damage resistance of fused silica. (authors)

Repair of oxidative DNA damage by amino acids.

Science.gov (United States)

Milligan, J R; Aguilera, J A; Ly, A; Tran, N Q; Hoang, O; Ward, J F

2003-11-01

Guanyl radicals, the product of the removal of a single electron from guanine, are produced in DNA by the direct effect of ionizing radiation. We have produced guanyl radicals in DNA by using the single electron oxidizing agent (SCN)2-, itself derived from the indirect effect of ionizing radiation via thiocyanate scavenging of OH. We have examined the reactivity of guanyl radicals in plasmid DNA with the six most easily oxidized amino acids cysteine, cystine, histidine, methionine, tryptophan and tyrosine and also simple ester and amide derivatives of them. Cystine and histidine derivatives are unreactive. Cysteine, methionine, tyrosine and particularly tryptophan derivatives react to repair guanyl radicals in plasmid DNA with rate constants in the region of approximately 10(5), 10(5), 10(6) and 10(7) dm3 mol(-1) s(-1), respectively. The implication is that amino acid residues in DNA binding proteins such as histones might be able to repair by an electron transfer reaction the DNA damage produced by the direct effect of ionizing radiation or by other oxidative insults.

Influence of acidic atmospheric deposition on soil solution composition in the Daniel Boone National Forest, Kentucky, USA

Science.gov (United States)

C.D. Barton; A.D. Karathanasis; G. Chalfant

2002-01-01

Acid atmosperic depositoin may enter an environmental ecosystem in a variety of forms and pathways, but the most common components include sulfuric and nitric acids formed when rainwater interacts with sulfur (SO3) and nitrogen (NO3) emmissions. For many soils and watersheds sensitive to acid deposition, the predominant...

Atmospheric dry and wet deposition of sulphur and nitrogen species and assessment of critical loads of acidic deposition exceedance in South Africa

Directory of Open Access Journals (Sweden)

Stuart J. Piketh

2011-03-01

Full Text Available We tested the hypothesis that acidic atmospheric pollution deposition, originating from the South African central industrial area, poses an environmental threat across a larger region within the dispersal footprint. A network of 37 passive monitoring sites to measure SO₂ and NO₂ was operated from August 2005 to September 2007. The area extended over the entire northern and eastern interior of South Africa. Monitoring locations were chosen to avoid direct impacts from local sources such as towns, mines and highways. Dry deposition rates of SO₂ and NO₂ were calculated from the measured concentrations. Concentrations of sulphur and nitrogen species in wet deposition from a previous study were used in conjunction with measured rainfall for the years 2006 and 2007 to estimate the wet deposition over the region. The calculated total (non-organic acidic deposition formed the basis for an assessment of exceedance of critical loads based on sensitivity of the regional soils. Regional soil sensitivity was determined by combining two major soil attributes available in the World Inventory of Soil Emission Potentials (International Soil Reference and Information Centre. Results indicate that certain parts of the central pollution source area on the South African Highveld have the potential for critical load exceedance, while limited areas downwind show lower levels of exceedance. Areas upwind and remote areas up and downwind, including forested areas of the Drakensberg escarpment, do not show any exceedance of the critical loads.

A conceptual framework: Redefining forest soil's critical acid loads under a changing climate

International Nuclear Information System (INIS)

McNulty, Steven G.; Boggs, Johnny L.

2010-01-01

Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it is believed to potentially impair forest health. The excess over the critical soil acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical soil acid load applies to exposure of the soil to a single, long-term pollutant (i.e., acidic deposition). However, ecosystems can be simultaneously under multiple ecosystem stresses and a single critical soil acid load level may not accurately reflect ecosystem health risk when subjected to multiple, episodic environmental stress. For example, the Appalachian Mountains of western North Carolina receive some of the highest rates of acidic deposition in the eastern United States, but these levels are considered to be below the critical acid load (CAL) that would cause forest damage. However, the area experienced a moderate three-year drought from 1999 to 2002, and in 2001 red spruce (Picea rubens Sarg.) trees in the area began to die in large numbers. The initial survey indicated that the affected trees were killed by the southern pine beetle (Dendroctonus frontalis Zimm.). This insect is not normally successful at colonizing these tree species because the trees produce large amounts of oleoresin that exclude the boring beetles. Subsequent investigations revealed that long-term acid deposition may have altered red spruce forest structure and function. There is some evidence that elevated acid deposition (particularly nitrogen) reduced tree water uptake potential, oleoresin production, and caused the trees to become more susceptible to insect colonization during the drought period

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

Science.gov (United States)

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

Chromium-induced membrane damage: protective role of ascorbic acid.

Science.gov (United States)

Dey, S K; Nayak, P; Roy, S

2001-07-01

Importance of chromium as environmental toxicant is largely due to impact on the body to produce cellular toxicity. The impact of chromium and their supplementation with ascorbic acid was studied on plasma membrane of liver and kidney in male Wistar rats (80-100 g body weight). It has been observed that the intoxication with chromium (i.p.) at the dose of 0.8 mg/100 g body weight per day for a period of 28 days causes significant increase in the level of cholesterol and decrease in the level of phospholipid of both liver and kidney. The alkaline phosphatase, total ATPase and Na(+)-K(+)-ATPase activities were significantly decreased in both liver and kidney after chromium treatment, except total ATPase activity of kidney. It is suggested that chromium exposure at the present dose and duration induce for the alterations of structure and function of both liver and kidney plasma membrane. Ascorbic acid (i.p. at the dose of 0.5 mg/100 g body weight per day for period of 28 days) supplementation can reduce these structural changes in the plasma membrane of liver and kidney. But the functional changes can not be completely replenished by the ascorbic acid supplementation in response to chromium exposure. So it is also suggested that ascorbic acid (nutritional antioxidant) is useful free radical scavenger to restrain the chromium-induced membrane damage.

Impact of acid atmospheric deposition on soils : quantification of chemical and hydrologic processes

NARCIS (Netherlands)

Grinsven, van J.J.M.

1988-01-01

Atmospheric deposition of SO _x , NOx and NHx will cause major changes in the chemical composition of solutions in acid soils, which may affect the biological functions of the soil. This thesis deals with quantification of soil acidification by means of chemical

Renal-protective and ameliorating impacts of omega-3 fatty acids against aspartame damaged MDCK cells.

Science.gov (United States)

Pandurangan, Muthuraman; Enkhtaivan, Gansukh; Veerappan, Muthuviveganandavel; Mistry, Bhupendra; Patel, Rahul; Moon, So Hyun; Nagajyothi, Patnamsetty Chidanandha; Kim, Doo Hwan

2017-11-01

Aspartame is widely used artificial sweeteners as food additives. Several researchers have pointed that the controversial report on the use of aspartame over more than decades. Omega-3 fatty acids are essential and unsaturated fatty acids, and it plays a remarkable role in vision, intelligence, neural development, and metabolism of neurotransmitters. Therefore, the present study was aimed to investigate the effect of omega-3 fatty acids on aspartame treated renal cells. Experimental groups were divided into three such as sham control, aspartame treated, and aspartame with omega-3 fatty acids. Cell viability was determined by sulforhodamine-b assay and flow cytometric analysis. The experimental results showed that the aspartame induced altered cell viability were reduced following treatment of aspartame with omega-3 fatty acids. Altered cell morphology was recovered by omega-3 fatty acids. DNA damage appeared in the highest concentration of aspartame used in this study. DNA damage characteristics such as comet tail and tiny head sections did not appear in the omega-3 fatty acids treated cells. Several microvilli and vesicular structures were found in aspartame treated cells. Altered morphology such as rounding, microvilli, and formation of dome-like structures did not appear in the omega-3 fatty acids with aspartame treated cells. Caspase-3 mRNA and protein expression were increased in aspartame treated cells, and these levels were reduced following omega-3 fatty acids treatment. Taking all these data together, it is suggested that the omega-3 fatty acids may be a therapeutic agent to reduce the aspartame induced biochemical and morphological alterations in normal renal cells. © 2017 BioFactors, 43(6):847-857, 2017. © 2017 International Union of Biochemistry and Molecular Biology.

Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York

Science.gov (United States)

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.

Long-term changes in soil and stream chemistry across an acid deposition gradient in the northeastern United States

Science.gov (United States)

Siemion, Jason; McHale, Michael; Lawrence, Gregory B.; Burns, Douglas A.; Antidormi, Michael

2018-01-01

Declines in acidic deposition across Europe and North America have led to decreases in surface water acidity and signs of chemical recovery of soils from acidification. To better understand the link between recovery of soils and surface waters, chemical trends in precipitation, soils, and streamwater were investigated in three watersheds representing a depositional gradient from high to low across the northeastern United States. Significant declines in concentrations of H+ (ranging from −1.2 to −2.74 microequivalents [μeq] L−1 yr−1), NO3− (ranging from −0.6 to −0.84 μeq L−1 yr−1), and SO42− (ranging from −0.95 to −2.13 μeq L−1 yr−1) were detected in precipitation in the three watersheds during the period 1999 to 2013. Soil chemistry in the A horizon of the watershed with the greatest decrease in deposition showed significant decreases in exchangeable Al and increases in exchangeable bases. Soil chemistry did not significantly improve during the study in the other watersheds, and base saturation in the Oa and upper B horizons significantly declined in the watershed with the smallest decrease in deposition. Streamwater SO42−concentrations significantly declined in all three streams (ranging from −2.01 to −2.87 μeq L−1 yr−1) and acid neutralizing capacity increased (ranging from 1.38 to 1.60 μeq L−1 yr−1) in the two streams with the greatest decreases in deposition. Recovery of soils has likely been limited by decades of acid deposition that have leached base cations from soils with base-poor parent material.

Protective effect of 4-coumaric acid from UVB ray damage in the rabbit eye.

Science.gov (United States)

Lodovici, Maura; Caldini, Silvia; Morbidelli, Lucia; Akpan, Victor; Ziche, Marina; Dolara, Piero

2009-01-08

UV-induced oxidation damage seems to play a major role in a number of specific pathological conditions of intraocular tissues, such as cataract formation and retinal degeneration. Therefore, antioxidant and/or scavenger compounds might protect the eyes from UV-induced cellular damage. We previously reported that 4-coumaric acid (4-CA) is able to protect rabbit corneal-derived cells (SIRC) from UVB-induced oxidation damage. In this study we evaluated the protective effect of 4-CA against UVB-induced cell damage in rabbit cornea in vivo. Twelve male New Zealand albino rabbits were used; four rabbits were used as a control and received vehicle in one eye and 4-CA acid in the contralateral eye; eight rabbits were exposed to UVB rays (79.2mJ/cm(2)) and three days before to UV exposure each animal received 1 drop/day of vehicle in one eye and 1 drop/day of vehicle containing 4-CA (164ng) in the contralateral eye. Corneal and sclera tissues were removed and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) levels were measured. Superoxide dismutase (SOD) and xanthine oxidase (XO) activities were determined in aqueous humour. UVB-induced vessel hyper-reactivity was strongly reduced at 4 and 24h after UVB exposure after local treatment with 4-CA, 8-oxodGuo levels, a marker of oxidative DNA damage, were significantly increased (Peyes. Our results indicate that the administration of 4-CA protects eye tissues, thus reducing the harmful effect of UVB radiation at low concentration, probably through its free radical scavenging and antioxidant properties. Therefore, 4-CA may be useful in protecting the eye from free radical damage following UVB exposure from sunlight, UV lamps and welding torches.

Acid Deposition Maps in Spain

International Nuclear Information System (INIS)

Artinano, B.; Cabal, H.; Garcia, C.

1998-01-01

Animal and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To do this, updated databases with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5x5 Km 2 grid which allow to assess the methodology used in Europe to obtain the maps of excedances over the critical loads of pollutants. (Author) 32 refs

Acid rain attack on outdoor sculpture in perspective

Science.gov (United States)

Livingston, Richard A.

2016-12-01

A major concern motivating research in acid rain materials effects has been the potential for damage to cultural heritage, particularly outdoor marble and bronze sculpture. However, a combination of field and laboratory studies has failed to show a correlation between rain pH and loss of materials. In order to understand this counterintuitive lack of acid rain effect, an aqueous geochemical modeling approach was used to analyze rain runoff chemistry for the relative importance of acid rain neutralization, dry deposition, and in the case of marble, natural carbonate dissolution. This approach involved the development of pH - SO42- phase diagrams for marble (calcium carbonate) and bronze (copper) under ambient environmental conditions. This then enabled reaction path modeling of the acid neutralization process using the pH range typically found in wet deposition (3.5-6). The results were for marble that the theoretical maximum amount of Ca2+ ion that could be lost due acid rain neutralization would be 0.158 mmol/l compared to 10.5 mmol/l by dry deposition, and for bronze, the Cu2+ ion losses would be 0.21 mmol/l and 47.3 mmol/l respectively. Consequently dry deposition effects on these materials have the potential to dominate over wet deposition effects. To test these predictions the geochemical models were applied to examples of data sets from mass balance (runoff vs rainfall) studies on a marble statue in New York City and some bronze memorial plaques at Gettysburg PA. Although these data sets were collected in the early 1980s they remain valid for demonstrating the mass balance method. For the marble statue, the mean Ca2+ losses by dry deposition was about 69% of the total compared 0.3% for acid rain neutralization, which was less than the natural carbonate dissolution losses of 0.8%. For the bronze, the mean Cu2+ losses were 70.6% by SO42- dry deposition and 23% by NO3- dry deposition compared to 6.4% by acid rain neutralization. Thus for both cases the wet

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

Science.gov (United States)

Baedecker, Philip A.; Reddy, Michael M.; Reimann, Karl J.; Sciammarella, Cesar A.

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 μm yr -1 for marble, and from ˜ 25 to ˜ 45 μm 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

Nutritional Manipulation of Primate Retinas, V: Effects of Lutein, Zeaxanthin, and n–3 Fatty Acids on Retinal Sensitivity to Blue-Light–Induced Damage

Science.gov (United States)

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

Laser damage studies on MgF2 thin films

International Nuclear Information System (INIS)

Protopapa, Maria Lucia; De Tomasi, Ferdinando; Perrone, Maria Rita; Piegari, Angela; Masetti, Enrico; Ristau, Detlev; Quesnel, Etienne; Duparre, Angela

2001-01-01

The results of laser damage studies performed at 248 nm (KrF excimer laser) on MgF 2 thin films deposited by different techniques (electron-beam evaporation, thermal boat evaporation, and ion-beam sputtering) on fused silica and CaF 2 substrates are presented. We find that the films deposited on CaF 2 substrates by the electron-beam evaporation technique present the highest damage threshold fluence (9 J/cm2). The photoacoustic (PA) beam deflection technique was employed, in addition to microscopical inspection, to determine laser damage fluences. We confirm, by scanning electron microscopy analysis of the damaged spots, the capability of the PA technique to provide information on the mechanisms leading to damage. The dependence of both laser damage fluence and damage morphology on the film deposition technique, as well as on the film substrate, is discussed

1.6. The kinetics of hydrochloric acid decomposition of argillite of Chashma-Sang Deposit

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Mirzoev, D.Kh.; Boboev, Kh.E.

2016-01-01

Present article of book is devoted to kinetics of hydrochloric acid decomposition of argillite of Chashma-Sang Deposit. It was defined that with temperature increasing the extraction rate of Al_2O_3 and Fe_2O_3 increases. The dependence of extraction rate of Al_2O_3 and Fe_2O_3 on process duration at hydrochloric acid decomposition of argillite was studied. The activation energy of the process was defined.

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

Science.gov (United States)

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.

The effects of topically applied glycolic acid and salicylic acid on ultraviolet radiation-induced erythema, DNA damage and sunburn cell formation in human skin.

Science.gov (United States)

Kornhauser, Andrija; Wei, Rong-Rong; Yamaguchi, Yuji; Coelho, Sergio G; Kaidbey, Kays; Barton, Curtis; Takahashi, Kaoruko; Beer, Janusz Z; Miller, Sharon A; Hearing, Vincent J

2009-07-01

alpha-Hydroxy acids (alphaHAs) are reported to reduce signs of aging in the skin and are widely used cosmetic ingredients. Several studies suggest that alphaHA can increase the sensitivity of skin to ultraviolet radiation. More recently, beta-hydroxy acids (betaHAs), or combinations of alphaHA and betaHA have also been incorporated into antiaging skin care products. Concerns have also arisen about increased sensitivity to ultraviolet radiation following use of skin care products containing beta-HA. To determine whether topical treatment with glycolic acid, a representative alphaHA, or with salicylic acid, a betaHA, modifies the short-term effects of solar simulated radiation (SSR) in human skin. Fourteen subjects participated in this study. Three of the four test sites on the mid-back of each subject were treated daily Monday-Friday, for a total of 3.5 weeks, with glycolic acid (10%), salicylic acid (2%), or vehicle (control). The fourth site received no treatment. After the last treatment, each site was exposed to SSR, and shave biopsies from all four sites were obtained. The endpoints evaluated in this study were erythema (assessed visually and instrumentally), DNA damage and sunburn cell formation. Treatment with glycolic acid resulted in increased sensitivity of human skin to SSR, measured as an increase in erythema, DNA damage and sunburn cell formation. Salicylic acid did not produce significant changes in any of these biomarkers. Short-term topical application of glycolic acid in a cosmetic formulation increased the sensitivity of human skin to SSR, while a comparable treatment with salicylic acid did not.

Laboratory study on leaching of a sandstone-type uranium deposit for acid in-situ leaching

International Nuclear Information System (INIS)

Wen Zhenqian; Yao Yixuan; Zheng Jianping; Jiang Yan; Cui Xin; Xing Yongguo; Hao Jinting; Tang Huazhang

2013-01-01

Ore samples were took from in-situ leaching experiment boreholes in a sandstone-type uranium deposit. Technological mineralogy study, agitating leaching and column leaching experiments were carried. The results show that the content of minerals consuming acid and deoxidized minerals is low. When sulfuric acid concentration was 1O g/L, initial uranium content was 0.0224%, and liquid-to-solid ratio was l.91, leaching rate of column leaching experiments is 89.19%, acid consumption is 8.2 kg/t ore, acid consumption is 41.88 t/tU. Acid leaching, technology is recommend for field in-situ leaching experiment, sulfuric acid concentration in confecting solution is 10 g/L, and oxidizing agent is needless during leaching process. (authors)

Changing public interest in, and awareness of, acid deposition: some evidence from the UK

International Nuclear Information System (INIS)

Longhurst, J.W.S.; Bantock, J.; Hare, S.E.; Conlan, D.E.

1995-01-01

It is fundamental that the general public have access to usable environmental information on which they can base their decisions. Since 1984 the Atmospheric Research and Information Centre (ARIC) has operated a public information programme for the UK on the subject of acid deposition. The objective of the programme is to disseminate information on acid deposition without advocacy. ARIC provides enquiries with a broad range of authoritative and accurate facts and opinions from a wide range of parties from all sides of the debate. These sources include pressure groups, governmental bodies and industrialists from the UK and overseas. By deconstructing complex technical material and reassembling it for dissemination in a user friendly form, ARIC assists those receiving information to obtain a balanced perspective. This enables personal decision making within the context of the fullest information resource ARIC is able to provide. 8 refs., 4 tabs

Changing public interest in, and awareness of, acid deposition: some evidence from the UK

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S.; Bantock, J.; Hare, S.E.; Conlan, D.E. [Manchester Metropolitan University, Manchester (United Kingdom). Dept. of Environmental and Geographical Sciences

1995-12-01

It is fundamental that the general public have access to usable environmental information on which they can base their decisions. Since 1984 the Atmospheric Research and Information Centre (ARIC) has operated a public information programme for the UK on the subject of acid deposition. The objective of the programme is to disseminate information on acid deposition without advocacy. ARIC provides enquiries with a broad range of authoritative and accurate facts and opinions from a wide range of parties from all sides of the debate. These sources include pressure groups, governmental bodies and industrialists from the UK and overseas. By deconstructing complex technical material and reassembling it for dissemination in a user friendly form, ARIC assists those receiving information to obtain a balanced perspective. This enables personal decision making within the context of the fullest information resource ARIC is able to provide. 8 refs., 4 tabs.

The response of soil and stream chemistry to decreases in acid deposition in the Catskill Mountains, New York, USA.

Science.gov (United States)

McHale, Michael R; Burns, Douglas A; Siemion, Jason; Antidormi, Michael R

2017-10-01

The Catskill Mountains have been adversely impacted by decades of acid deposition, however, since the early 1990s, levels have decreased sharply as a result of decreases in emissions of sulfur dioxide and nitrogen oxides. This study examines trends in acid deposition, stream-water chemistry, and soil chemistry in the southeastern Catskill Mountains. We measured significant reductions in acid deposition and improvement in stream-water quality in 5 streams included in this study from 1992 to 2014. The largest, most significant trends were for sulfate (SO 4 2- ) concentrations (mean trend of -2.5 μeq L -1 yr -1 ); hydrogen ion (H + ) and inorganic monomeric aluminum (Al im ) also decreased significantly (mean trends of -0.3 μeq L -1 yr -1 for H + and -0.1 μeq L -1 yr -1 for Al im for the 3 most acidic sites). Acid neutralizing capacity (ANC) increased by a mean of 0.65 μeq L -1 yr -1 for all 5 sites, which was 4 fold less than the decrease in SO 4 2- concentrations. These upward trends in ANC were limited by coincident decreases in base cations (-1.3 μeq L -1 yr -1 for calcium + magnesium). No significant trends were detected in stream-water nitrate (NO 3 - ) concentrations despite significant decreasing trends in NO 3 - wet deposition. We measured no recovery in soil chemistry which we attributed to an initially low soil buffering capacity that has been further depleted by decades of acid deposition. Tightly coupled decreasing trends in stream-water silicon (Si) (-0.2 μeq L -1 yr -1 ) and base cations suggest a decrease in the soil mineral weathering rate. We hypothesize that a decrease in the ionic strength of soil water and shallow groundwater may be the principal driver of this apparent decrease in the weathering rate. A decreasing weathering rate would help to explain the slow recovery of stream pH and ANC as well as that of soil base cations. Published by Elsevier Ltd.

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

Science.gov (United States)

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.

Critical Loads of Acid Deposition for Wilderness Lakes in the Sierra Nevada (California) Estimated by the Steady-State Water Chemistry Model

Science.gov (United States)

Glenn D. Shaw; Ricardo Cisneros; Donald Schweizer; James O. Sickman; Mark E. Fenn

2014-01-01

Major ion chemistry (2000-2009) from 208 lakes (342 sample dates and 600 samples) in class I and II wilderness areas of the Sierra Nevada was used in the Steady-State Water Chemistry (SSWC) model to estimate critical loads for acid deposition and investigate the current vulnerability of high elevation lakes to acid deposition. The majority of the lakes were dilute (...

Antibacterial Effect of Gallic Acid against Aeromonas hydrophila and Aeromonas sobria Through Damaging Membrane Integrity.

Science.gov (United States)

Lu, Jing; Wang, Zhenning; Ren, Mengrou; Huang, Guoren; Fang, Baochen; Bu, Xiujuan; Liu, Yanhui; Guan, Shuang

In the study, we investigated the antibacterial activity and mechanism of gallic acid against Aeromonas hydrophila and Aeromonas sobria. Gallic acid showed strong antimicrobial activity against the two bacteria. Furthermore, the antibacterial mechanism of gallic acid (0, 3, 6, 12 mM) was performed by membrane integrity assay and scanning electron microscopy (SEM) assay. The results showed that gallic acid notably increased the released material absorption value at 260, 280 nm and electric conductivity in a dose-dependent manner. Moreover, the SEM assay showed that gallic acid induced severe shrink of bacterial intima and irregular morphology in a dose-dependent manner. The SDS-PAGE profiles further confirmed that gallic acid could damage bacterial cells. These results indicated gallic acid exhibited antibacterial effect by destroying membrane integrity of A. hydrophila and A. sobria. Hence, gallic acid has great potential as a new natural food preservative in food fresh-keeping and storage.

Distribution and Orientation of Carbon Fibers in Polylactic Acid Parts Produced by Fused Deposition Modeling

DEFF Research Database (Denmark)

Hofstätter, Thomas; W. Gutmann, Ingomar; Koch, Thomas

2016-01-01

The aim of this paper is the understanding of the fiber orientation by investigations in respect to the inner configuration of a polylactic acid matrix reinforced with short carbon fibers after a fused deposition modeling extrusion process. The final parts were analyzed by X-ray, tomography......, and magnetic resonance imaging allowing a resolved orientation of the fibers and distribution within the part. The research contributes to the understanding of the fiber orientation and fiber reinforcement of fused deposition modeling parts in additive manufacturing....

UDP-glucuronosyltransferase-dependent bioactivation of clofibric acid to a DNA-damaging intermediate in mouse hepatocytes.

Science.gov (United States)

Ghaoui, Roula; Sallustio, Benedetta C; Burcham, Philip C; Fontaine, Frank R

2003-05-06

Glucuronidation of a number of carboxyl-containing drugs generates reactive acyl glucuronide metabolites. These electrophilic species alkylate cell proteins and may be implicated in the pathogenesis of a number of toxic syndromes seen in patients receiving the parent aglycones. Whether acyl glucuronides also attack nuclear DNA is unknown, although the acyl glucuronide formed from clofibric acid was recently found to decrease the transfection efficiency of phage DNA and generate strand breaks in plasmid DNA in vitro. To determine if such a DNA damage occurs within a cellular environment, the comet assay (i.e. single-cell gel electrophoresis) was used to detect DNA lesions in the nuclear genome of isolated mouse hepatocytes cultured with clofibric acid. Overnight exposure to 50 microM and higher concentrations of clofibric acid produced concentration-dependent increases in the comet areas of hepatocyte nuclei, with 1 mM clofibrate producing a 3.6-fold elevation over controls. These effects closely coincided with culture medium concentrations of the glucuronide metabolite formed from clofibric acid, 1-O-beta-clofibryl glucuronide. Consistent with a role for glucuronidation in the DNA damage observed, the glucuronidation inhibitor borneol diminished glucuronide formation from 100 microM clofibrate by 98% and returned comet areas to baseline levels. Collectively, these results suggest that the acyl glucuronide formed from clofibric acid is capable of migrating from its site of formation within the endoplasmic reticulum to generate strand nicks in nuclear DNA.

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

Science.gov (United States)

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.

Effects of decreasing acid deposition and climate change on acid extremes in an upland stream

Directory of Open Access Journals (Sweden)

C. D. Evans

2008-03-01

Full Text Available This study assesses the major chemical processes leading to acid extremes in a small, moorland stream in mid-Wales, UK, which has been monitored since 1979. Results suggest that base cation (mainly calcium dilution, the "sea-salt effect", and elevated nitrate pulses, are the major causes of seasonal/episodic minima in acid neutralising capacity (ANC, and that the relative importance of these drivers has remained approximately constant during 25 years of decreasing acid deposition and associated long-term chemical recovery. Many of the chemical variations causing short-term reductions in stream acidity, particularly base cation dilution and organic acid increases, are closely related to changes in water-flowpath and therefore to stream discharge. Changes in the observed pH-discharge relationship over time indicate that high-flow pH has increased more rapidly than mean-flow pH, and therefore that episodes have decreased in magnitude since 1980. However a two-box application of the dynamic model MAGIC, whilst reproducing this trend, suggests that it will not persist in the long term, with mean ANC continuing to increase until 2100, but the ANC of the upper soil (the source of relatively acid water during high-flow episodes stabilising close to zero beyond 2030. With climate change predicted to lead to an increase in maximum flows in the latter half of the century, high-flow related acid episodes may actually become more rather than less severe in the long term, although the model suggests that this effect may be small. Two other predicted climatic changes could also detrimentally impact on acid episodes: increased severity of winter "sea-salt" episodes due to higher wind speeds during winter storms; and larger sulphate pulses due to oxidation of reduced sulphur held in organic soils, during more extreme summer droughts. At the Gwy, the near-coastal location and relatively small extent of peat soils suggest that sea-salt episodes may have the

Citric acid enhances the phytoextraction of manganese and plant growth by alleviating the ultrastructural damages in Juncus effusus L

Energy Technology Data Exchange (ETDEWEB)

Najeeb, U.; Xu, L.; Ali, Shafaqat [Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China); Jilani, Ghulam, E-mail: jilani@uaar.edu.pk [Department of Soil Science, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Punjab 46300 (Pakistan); Gong, H.J. [Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China); Shen, W.Q. [The University of Nottingham at Ningbo, Ningbo 315100 (China); Zhou, W.J., E-mail: wjzhou@zju.edu.cn [Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029 (China)

2009-10-30

Chelate-assisted phytoextraction by high biomass producing plant species enhances the removal of heavy metals from polluted environments. In this regard, Juncus effusus a wetland plant has great potential. This study evaluated the effects of elevated levels of manganese (Mn) on the vegetative growth, Mn uptake and antioxidant enzymes in J. effusus. We also studied the role of citric acid and EDTA on improving metal accumulation, plant growth and Mn toxicity stress alleviation. Three-week-old plantlets of J. effusus were subjected to various treatments in the hydroponics as: Mn (50, 100 and 500 {mu}M) alone, Mn (500 {mu}M) + citric acid (5 mM), and Mn (500 {mu}M) + EDTA (5 mM). After 2 weeks of treatment, higher Mn concentrations significantly reduced the plant biomass and height. Both citric acid and EDTA restored the plant height as it was reduced at the highest Mn level. Only the citric acid (but not EDTA) was able to recover the plant biomass weight, which was also obvious from the microscopic visualization of mesophyll cells. There was a concentration dependent increase in Mn uptake in J. effusus plants, and relatively more deposition in roots compared to aerial parts. Although both EDTA and citric acid caused significant increase in Mn accumulation; however, the Mn translocation was enhanced markedly by EDTA. Elevated levels of Mn augmented the oxidative stress, which was evident from changes in the activities of antioxidative enzymes in plant shoots. Raised levels of lipid peroxidation and variable changes in the activities of antioxidant enzymes were recorded under Mn stress. Electron microscopic images revealed several modifications in the plants at cellular and sub-cellular level due to the oxidative damage induced by Mn. Changes in cell shape and size, chloroplast swelling, increased number of plastoglobuli and disruption of thylakoid were noticed. However, these plants showed a high degree of tolerance against Mn toxicity stress, and it removed

Citric acid enhances the phytoextraction of manganese and plant growth by alleviating the ultrastructural damages in Juncus effusus L

International Nuclear Information System (INIS)

Najeeb, U.; Xu, L.; Ali, Shafaqat; Jilani, Ghulam; Gong, H.J.; Shen, W.Q.; Zhou, W.J.

2009-01-01

Chelate-assisted phytoextraction by high biomass producing plant species enhances the removal of heavy metals from polluted environments. In this regard, Juncus effusus a wetland plant has great potential. This study evaluated the effects of elevated levels of manganese (Mn) on the vegetative growth, Mn uptake and antioxidant enzymes in J. effusus. We also studied the role of citric acid and EDTA on improving metal accumulation, plant growth and Mn toxicity stress alleviation. Three-week-old plantlets of J. effusus were subjected to various treatments in the hydroponics as: Mn (50, 100 and 500 μM) alone, Mn (500 μM) + citric acid (5 mM), and Mn (500 μM) + EDTA (5 mM). After 2 weeks of treatment, higher Mn concentrations significantly reduced the plant biomass and height. Both citric acid and EDTA restored the plant height as it was reduced at the highest Mn level. Only the citric acid (but not EDTA) was able to recover the plant biomass weight, which was also obvious from the microscopic visualization of mesophyll cells. There was a concentration dependent increase in Mn uptake in J. effusus plants, and relatively more deposition in roots compared to aerial parts. Although both EDTA and citric acid caused significant increase in Mn accumulation; however, the Mn translocation was enhanced markedly by EDTA. Elevated levels of Mn augmented the oxidative stress, which was evident from changes in the activities of antioxidative enzymes in plant shoots. Raised levels of lipid peroxidation and variable changes in the activities of antioxidant enzymes were recorded under Mn stress. Electron microscopic images revealed several modifications in the plants at cellular and sub-cellular level due to the oxidative damage induced by Mn. Changes in cell shape and size, chloroplast swelling, increased number of plastoglobuli and disruption of thylakoid were noticed. However, these plants showed a high degree of tolerance against Mn toxicity stress, and it removed substantial

Effects of formic acid hydrolysis on the quantitative analysis of radiation-induced DNA base damage products assayed by gas chromatography/mass spectrometry

International Nuclear Information System (INIS)

Swarts, S.G.; Smith, G.S.; Miao, L.; Wheeler, K.T.

1996-01-01

Gas chromatography/mass spectrometry (GC/ MS-SIM) is an excellent technique for performing both qualitative and quantitative analysis of DNA base damage products that are formed by exposure to ionizing radiation or by the interaction of intracellular DNA with activated oxygen species. This technique commonly uses a hot formic acid hydrolysis step to degrade the DNA to individual free bases. However, due to the harsh nature of this degradation procedure, the quantitation of DNA base damage products may be adversely affected. Consequently, we examined the effects of various formic acid hydrolysis procedures on the quantitation of a number of DNA base damage products and identified several factors that can influence this quantitation. These factors included (1) the inherent acid stabilities of both the lesions and the internal standards; (2) the hydrolysis temperature; (3) the source and grade of the formic acid; and (4) the sample mass during hydrolysis. Our data also suggested that the N, O-bis (trimethylsilyl)trifluoroacetamide (BSTFA) derivatization efficiency can be adversely affected, presumably by trace contaminants either in the formic acid or from the acid-activated surface of the glass derivatization vials. Where adverse effects were noted, modifications were explored in an attempt to improve the quantitation of these DNA lesions. Although experimental steps could be taken to minimize the influence of these factors on the quantitation of some base damage products, no single procedure solved the quantitation problem for all base lesions. However, a significant improvement in the quantitation was achieved if the relative molecular response factor (RMRF) values for these lesions were generated with authentic DNA base damage products that had been treated exactly like the experimental samples. (orig.)

The response of soil and stream chemistry to decreases in acid deposition in the Catskill Mountains, New York, USA

Science.gov (United States)

McHale, Michael; Burns, Douglas A.; Siemion, Jason; Antidormi, Michael

2017-01-01

The Catskill Mountains have been adversely impacted by decades of acid deposition, however, since the early 1990s, levels have decreased sharply as a result of decreases in emissions of sulfur dioxide and nitrogen oxides. This study examines trends in acid deposition, stream-water chemistry, and soil chemistry in the southeastern Catskill Mountains. We measured significant reductions in acid deposition and improvement in stream-water quality in 5 streams included in this study from 1992 to 2014. The largest, most significant trends were for sulfate (SO42−) concentrations (mean trend of −2.5 μeq L−1 yr−1); hydrogen ion (H+) and inorganic monomeric aluminum (Alim) also decreased significantly (mean trends of −0.3 μeq L−1 yr−1 for H+ and −0.1 μeq L−1 yr−1 for Alim for the 3 most acidic sites). Acid neutralizing capacity (ANC) increased by a mean of 0.65 μeq L−1 yr−1 for all 5 sites, which was 4 fold less than the decrease in SO42−concentrations. These upward trends in ANC were limited by coincident decreases in base cations (−1.3 μeq L−1 yr−1 for calcium + magnesium). No significant trends were detected in stream-water nitrate (NO3−) concentrations despite significant decreasing trends in NO3− wet deposition. We measured no recovery in soil chemistry which we attributed to an initially low soil buffering capacity that has been further depleted by decades of acid deposition. Tightly coupled decreasing trends in stream-water silicon (Si) (−0.2 μeq L−1 yr−1) and base cations suggest a decrease in the soil mineral weathering rate. We hypothesize that a decrease in the ionic strength of soil water and shallow groundwater may be the principal driver of this apparent decrease in the weathering rate. A decreasing weathering rate would help to explain the slow recovery of stream pH and ANC as well as that of soil base cations.

Hexanoic Acid Treatment Prevents Systemic MNSV Movement in Cucumis melo Plants by Priming Callose Deposition Correlating SA and OPDA Accumulation

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Emma Fernández-Crespo

2017-10-01

Full Text Available Unlike fungal and bacterial diseases, no direct method is available to control viral diseases. The use of resistance-inducing compounds can be an alternative strategy for plant viruses. Here we studied the basal response of melon to Melon necrotic spot virus (MNSV and demonstrated the efficacy of hexanoic acid (Hx priming, which prevents the virus from systemically spreading. We analysed callose deposition and the hormonal profile and gene expression at the whole plant level. This allowed us to determine hormonal homeostasis in the melon roots, cotyledons, hypocotyls, stems and leaves involved in basal and hexanoic acid-induced resistance (Hx-IR to MNSV. Our data indicate important roles of salicylic acid (SA, 12-oxo-phytodienoic acid (OPDA, jasmonic-isoleucine, and ferulic acid in both responses to MNSV. The hormonal and metabolites balance, depending on the time and location associated with basal and Hx-IR, demonstrated the reprogramming of plant metabolism in MNSV-inoculated plants. The treatment with both SA and OPDA prior to virus infection significantly reduced MNSV systemic movement by inducing callose deposition. This demonstrates their relevance in Hx-IR against MNSV and a high correlation with callose deposition. Our data also provide valuable evidence to unravel priming mechanisms by natural compounds.

Assessing future economic impacts of acidic deposition on the recreational fishery of eastern Canada

International Nuclear Information System (INIS)

1990-01-01

A study was carried out to assess the socio-economic impacts and net economic value effects related to potential reduction in acidic deposition on the sports fishery of eastern Canada. Impacts and net economic effects that would have occurred from 1950 to 1985 if emission/deposition controls were in place are measured. Impacts and net economic effects that will occur from 1986 to 2021 if controls are put in place in the future are also measured. The study incorporated the latest data describing the relationship of acidic deposition to lake pH levels and ultimate impact on fish survival, and applies a spatial analysis system to model changes in sport fish availability with respect to pH changes and fish survival responses. It was found that if emission controls were put in place beginning in 1950 the Canadian economy would have accrued $4.3 billion in net economic value from 1950 to 1985 inclusive. The 1986 value of the historical stream of losses that occurred because controls were not put in place is $24 billion assuming a 10% rate of return. If controls were put in place in the future, net economic value to Canada due to increased angler activity would be $4.2 billion for the period 1986-2021. The value in 1986 would be $925 million. 9 figs., 34 tabs

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystem

Energy Technology Data Exchange (ETDEWEB)

Schuurkes, J.A.A.R.; Heck, I.C.C; Hesen, P.L.G.M.; Leuven, R.S.E.W.; Roelofs, J.G.M.

1986-11-01

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H/sub 2/SO/sub 4/ and nitrate, and rain water containing ammonium sulphate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulphate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulphate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH 3.8. Under acidified conditions, ammonium sulphate deposition led to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H/sub 2/SO/sub 4/ deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr, the acidification of water appeared to be coupled with changes in alkalinity, sulphate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH/sub 3/-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulphate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters. 10 references.

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystems

Energy Technology Data Exchange (ETDEWEB)

Schuurkes, J.A.; Heck, I.C.; Hesen, P.L.; Leuven, R.S.; Roelofs, J.G.

1986-11-01

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H/sub 2/SO/sub 4/ and nitrate, and rain water containing ammonium sulfate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulfate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulfate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH = 3.8. Under acidified conditions, ammonium sulfate deposition lead to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H/sub 2/SO/sub 4/ deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr. The acidification of water appeared to be coupled with changes in alkalinity, sulfate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH/sub 3/-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulfate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters. 10 refs.

Polymer deposition morphology by electrospray deposition - Modifications through distance variation

International Nuclear Information System (INIS)

Altmann, K.; Schulze, R.-D.; Friedrich, J.

2014-01-01

Electrospray deposition (ESD) of highly diluted polymers was examined with regard to the deposited surface structure. Only the flight distance (flight time) onto the resulting deposited surface was varied from 20 to 200 mm. An apparatus without any additional heating or gas flows was used. Polyacrylic acid (PAA) and polyallylamine (PAAm) in methanol were deposited on Si wafers. The polymer layers were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, derivatization reactions and Fourier transform infrared spectroscopy using a grazing incidence unit. SEM images illustrated the changing structures of PAA and PAAm. For PAA the deposited structure changed from a smooth film (20 mm) to a film with individual droplets on the coated surface (100 mm and 200 mm), while for PAAm individual droplets can be seen at all distances. The ESD process with cascades of splitting droplets slows down for PAA after distances greater than 40 mm. In contrast, the ESD process for PAAm is nearly stopped within the first flight distance of 20 mm. Residual solvent analysis showed that most of the solvent evaporated within the first 20 mm capillary-sample distance. - Highlights: • We deposited polyacrylic acid and polyallylamine by electrospray ionization (ESI). • The morphology in dependence of flight distance (20 mm to 200 mm) was analyzed. • The amount of residual solvent after deposition was determined. • ESI-process slows down for polyacrylic acid after 40 mm flight distance. • ESI-Process is complete for polyallylamine within the first 20 mm

Effects of deposition rates on laser damage threshold of TiO2/SiO2 high reflectors

International Nuclear Information System (INIS)

Yao Jianke; Xu Cheng; Ma Jianyong; Fang Ming; Fan Zhengxiu; Jin Yunxia; Zhao Yuanan; He Hongbo; Shao Jianda

2009-01-01

TiO 2 single layers and TiO 2 /SiO 2 high reflectors (HR) are prepared by electron beam evaporation at different TiO 2 deposition rates. It is found that the changes of properties of TiO 2 films with the increase of rate, such as the increase of refractive index and extinction coefficient and the decrease of physical thickness, lead to the spectrum shift and reflectivity bandwidth broadening of HR together with the increase of absorption and decrease of laser-induced damage threshold. The damages are found of different morphologies: a shallow pit to a seriously delaminated and deep crater, and the different amorphous-to-anatase-to-rutile phase transition processes detected by Raman study. The frequency shift of Raman vibration mode correlates with the strain in film. Energy dispersive X-ray analysis reveals that impurities and non-stoichiometric defects are two absorption initiations resulting to the laser-induced transformation.

The effect of pomegranate seed oil and grapeseed oil on cis-9, trans-11 CLA (rumenic acid), n-3 and n-6 fatty acids deposition in selected tissues of chickens.

Science.gov (United States)

Białek, A; Białek, M; Lepionka, T; Kaszperuk, K; Banaszkiewicz, T; Tokarz, A

2018-04-23

The aim of this study was to determine whether diet modification with different doses of grapeseed oil or pomegranate seed oil will improve the nutritive value of poultry meat in terms of n-3 and n-6 fatty acids, as well as rumenic acid (cis-9, trans-11 conjugated linoleic acid) content in tissues diversified in lipid composition and roles in lipid metabolism. To evaluate the influence of applied diet modification comprehensively, two chemometric methods were used. Results of cluster analysis demonstrated that pomegranate seed oil modifies fatty acids profile in the most potent way, mainly by an increase in rumenic acid content. Principal component analysis showed that regardless of type of tissue first principal component is strongly associated with type of deposited fatty acid, while second principal component enables identification of place of deposition-type of tissue. Pomegranate seed oil seems to be a valuable feed additive in chickens' feeding. © 2018 Blackwell Verlag GmbH.

VALUING ACID MINE DRAINAGE REMEDIATION OF IMPAIRED WATERWAYS IN WEST VIRGINIA: A HEDONIC MODELING APPROACH

Science.gov (United States)

States with active and abandoned mines face large private and public costs to remediate damage to streams and rivers from acid mine drainage (AMD), the metal rich runoff flowing primarily from abandoned mines and surface deposits of mine waste. AMD can lower stream and river pH ...

Maternal Docosahexaenoic Acid Increases Adiponectin and Normalizes IUGR-Induced Changes in Rat Adipose Deposition

Directory of Open Access Journals (Sweden)

Heidi N. Bagley

2013-01-01

Full Text Available Intrauterine growth restriction (IUGR predisposes to obesity and adipose dysfunction. We previously demonstrated IUGR-induced increased visceral adipose deposition and dysregulated expression of peroxisome proliferator activated receptor-γ2 (PPARγ2 in male adolescent rats, prior to the onset of obesity. In other studies, activation of PPARγ increases subcutaneous adiponectin expression and normalizes visceral adipose deposition. We hypothesized that maternal supplementation with docosahexaenoic acid (DHA, a PPARγ agonist, would normalize IUGR adipose deposition in association with increased PPARγ, adiponectin, and adiponectin receptor expression in subcutaneous adipose. To test these hypotheses, we used a well-characterized model of uteroplacental-insufficiency-(UPI- induced IUGR in the rat with maternal DHA supplementation. Our primary findings were that maternal DHA supplementation during rat pregnancy and lactation (1 normalizes IUGR-induced changes in adipose deposition and visceral PPARγ expression in male rats and (2 increases serum adiponectin, as well as adipose expression of adiponectin and adiponectin receptors in former IUGR rats. Our novel findings suggest that maternal DHA supplementation may normalize adipose dysfunction and promote adiponectin-induced improvements in metabolic function in IUGR.

Maternal docosahexaenoic acid increases adiponectin and normalizes IUGR-induced changes in rat adipose deposition.

Science.gov (United States)

Bagley, Heidi N; Wang, Yan; Campbell, Michael S; Yu, Xing; Lane, Robert H; Joss-Moore, Lisa A

2013-01-01

Intrauterine growth restriction (IUGR) predisposes to obesity and adipose dysfunction. We previously demonstrated IUGR-induced increased visceral adipose deposition and dysregulated expression of peroxisome proliferator activated receptor- γ 2 (PPAR γ 2) in male adolescent rats, prior to the onset of obesity. In other studies, activation of PPAR γ increases subcutaneous adiponectin expression and normalizes visceral adipose deposition. We hypothesized that maternal supplementation with docosahexaenoic acid (DHA), a PPAR γ agonist, would normalize IUGR adipose deposition in association with increased PPAR γ , adiponectin, and adiponectin receptor expression in subcutaneous adipose. To test these hypotheses, we used a well-characterized model of uteroplacental-insufficiency-(UPI-) induced IUGR in the rat with maternal DHA supplementation. Our primary findings were that maternal DHA supplementation during rat pregnancy and lactation (1) normalizes IUGR-induced changes in adipose deposition and visceral PPAR γ expression in male rats and (2) increases serum adiponectin, as well as adipose expression of adiponectin and adiponectin receptors in former IUGR rats. Our novel findings suggest that maternal DHA supplementation may normalize adipose dysfunction and promote adiponectin-induced improvements in metabolic function in IUGR.

Effect of acid deposition on Nanshan forest at Chongging in China

International Nuclear Information System (INIS)

Xu Xiaolei; Ogura, Norio

1992-01-01

Chongqing is the city where atmospheric pollution is severest in China, and the pH of rainwater has been measured every year since 1981, which is close to 4.0 now. In 1982, the decline of Pinus massoniana in Nanshan district in southeast Chongqing has occurred. The decline phenomena of this forest attracted attention also in foreign countries, and the various studies on its causes have been carried out, consequently, the main cause was presumed to be the compound effect of acid rain, acid mist and the damage by insects. It was clarified by the recent research that the dry and wet acid fallouts mainly composed of SO 2 are one of the important causes that brought about the decline of Pinus massoniana in Nanshan. The forest area in Nanshan is about 2000 ha, and almost the simple forest of Pinus massoniana that distributes at the elevation from 400 to 1400 m. The withering of a small number began to occur in 1982, but thereafter, the area of withering increased rapidly, and reached 41.8% of the total forest area in July, 1983. The decline still continues now. The direct effect of acid fallout to Nanshan forest and the indirect effect through soil are reported in this paper. (K.I.)

Stability of sputter deposited ZnO:Cr films against acids

International Nuclear Information System (INIS)

Shinoda, Makoto; Nishide, Toshikazu; Sawada, Yutaka; Hosaka, Masato; Matsumoto, Toshihiko.

1993-01-01

ZnO:Cr films were deposited on water-cooled soda-lime glass substrates at room temperature in an Ar atmosphere by rf magnetron sputtering of a ZnO target on which Cr chips were placed. The films exhibited extraordinary stability against acids such as HCl or HNO 3 , and also high resistivities similar to those of ZnO films. The addition of Cr suppressed the growth of ZnO grains which resulted in the formation of a dense film with a smooth surface. The stability and high resistivity displayed by the ZnO:Cr films can be attributed to the formation of a chromium-oxide-rich grain boundary. (author)

Zinc deposition and dissolution in methanesulfonic acid onto a carbon composite electrode as the negative electrode reactions in a hybrid redox flow battery

International Nuclear Information System (INIS)

Leung, P.K.; Ponce-de-Leon, C.; Low, C.T.J.; Walsh, F.C.

2011-01-01

Highlights: → Use methanesulfonic acid to avoid dendrite formation during a long (>4 h) zinc electrodeposition. → Electrochemical characterization of Zn(II) deposition and its morphology using methanesulfonic acid solutions. → Use of additives to improve the efficiency of zinc deposition and dissolution as the half cell reaction of a redox flow battery. - Abstract: Electrodeposition and dissolution of zinc in methanesulfonic acid were studied as the negative electrode reactions in a hybrid redox flow battery. Cyclic voltammetry at a rotating disk electrode was used to characterize the electrochemistry and the effect of process conditions on the deposition and dissolution rate of zinc in aqueous methanesulfonic acid. At a sufficiently high current density, the deposition process became a mass transport controlled reaction. The diffusion coefficient of Zn 2+ ions was 7.5 x 10 -6 cm 2 s -1 . The performance of the zinc negative electrode in a parallel plate flow cell was also studied as a function of Zn 2+ ion concentration, methanesulfonic acid concentration, current density, electrolyte flow rate, operating temperature and the addition of electrolytic additives, including potassium sodium tartarate, tetrabutylammonium hydroxide, and indium oxide. The current-, voltage- and energy efficiencies of the zinc-half cell reaction and the morphologies of the zinc deposits are also discussed. The energy efficiency improved from 62% in the absence of additives to 73% upon the addition of 2 x 10 -3 mol dm -3 of indium oxide as a hydrogen suppressant. In aqueous methanesulfonic acid with or without additives, there was no significant dendrite formation after zinc electrodeposition for 4 h at 50 mA cm -2 .

Anti-inflammatory and ameliorative effects of gallic acid on fluoxetine-induced oxidative stress and liver damage in rats.

Science.gov (United States)

Karimi-Khouzani, Omid; Heidarian, Esfandiar; Amini, Sayed Asadollah

2017-08-01

Fluoxetine-induced liver damage is a cause of chronic liver disease. In the present study the hepatoprotective effects of gallic acid against fluoxetine-induced liver damage were examined. Forty-eight male rats were divided into six groups as follow: group 1, the control group; group 2, rats receiving fluoxetine (24mg/kg bw daily, po) without treatment; group 3, rats receiving 24mg/kg bw fluoxetine, treated with 50mg/kg bw silymarin and groups 4, 5, and 6 in which gallic acid (50, 100, and 200mg/kg bw, po, respectively) was prescribed after the consumption of fluoxetine. The histopathological changes of hepatic tissues were checked out. Fluoxetine caused a significant increase in the levels of serum glutamate oxaloacetate transaminase (GOT), serum glutamate pyruvate transaminase (GPT), lipid profiles, urea, fasting blood sugar (FBS), creatinine (Cr), protein carbonyl (PC) content, malondialdehyde (MDA), and liver TNF-α as an inflammatory element. Also, the obtained results of group 2 revealed a significant decline in ferric reducing ability of plasma (FRAP), liver catalase (CAT), superoxide dismutase (SOD), and vitamin C levels. The treatment with gallic acid showed significant ameliorations in abnormalities of fluoxetine-induced liver injury as represented by the improvement of hepatic CAT, SOD activities, vitamin C levels, serum biochemical parameters, and histopathological changes, in addition to the recovery of antioxidant defense system status. Gallic acid has inhibitory effects on fluoxetine-induced liver damage. The effect of gallic acid is derived from free radical scavenging properties and the anti-inflammatory effect related to TNF-α. Copyright © 2017. Published by Elsevier Urban & Partner Sp. z o.o.

Post-processing of fused silica and its effects on damage resistance to nanosecond pulsed UV lasers.

Science.gov (United States)

Ye, Hui; Li, Yaguo; Zhang, Qinghua; Wang, Wei; Yuan, Zhigang; Wang, Jian; Xu, Qiao

2016-04-10

HF-based (hydrofluoric acid) chemical etching has been a widely accepted technique to improve the laser damage performance of fused silica optics and ensure high-power UV laser systems at designed fluence. Etching processes such as acid concentration, composition, material removal amount, and etching state (etching with additional acoustic power or not) may have a great impact on the laser-induced damage threshold (LIDT) of treated sample surfaces. In order to find out the effects of these factors, we utilized the Taguchi method to determine the etching conditions that are helpful in raising the LIDT. Our results show that the most influential factors are concentration of etchants and the material etched away from the viewpoint of damage performance of fused silica optics. In addition, the additional acoustic power (∼0.6  W·cm-2) may not benefit the etching rate and damage performance of fused silica. Moreover, the post-cleaning procedure of etched samples is also important in damage performances of fused silica optics. Different post-cleaning procedures were, thus, experiments on samples treated under the same etching conditions. It is found that the "spraying + rinsing + spraying" cleaning process is favorable to the removal of etching-induced deposits. Residuals on the etched surface are harmful to surface roughness and optical transmission as well as laser damage performance.

Spatial characterization of acid rain stress in Canadian Shield Lakes

Science.gov (United States)

Tanis, Fred J.

1987-01-01

The acidification of lake waters from airborne pollution is of continental proportions both in North America and Europe. A major concern of the acid rain problem is the cumulative ecosystem damage to lakes and forest. The number of lakes affected in northeastern U.S. and on the Canadian Shield is though to be enormous. How seasonal changes in lake transparency are related to annual acidic load was examined. The relationship between variations in lake acidification and ecophysical units was also examined. The utility of Thematic Mapper based observations to measure seasonal changes in the optical transparency in acid lakes was investigated. The potential for this optical response is related to a number of local ecophysical factors with bedrock geology being, perhaps, the most important. Other factors include sulfate deposition, vegetative cover, and terrain drainage/relief. The area of southern Ontario contains a wide variety of geologies from the most acid rain sensitive granite quartzite types to the least sensitive limestone dolomite sediments. Annual sulfate deposition ranges from 1.0 to 4.0 grams/sq m.

Nucleosome acidic patch promotes RNF168- and RING1B/BMI1-dependent H2AX and H2A ubiquitination and DNA damage signaling.

Directory of Open Access Journals (Sweden)

Justin W Leung

2014-03-01

Full Text Available Histone ubiquitinations are critical for the activation of the DNA damage response (DDR. In particular, RNF168 and RING1B/BMI1 function in the DDR by ubiquitinating H2A/H2AX on Lys-13/15 and Lys-118/119, respectively. However, it remains to be defined how the ubiquitin pathway engages chromatin to provide regulation of ubiquitin targeting of specific histone residues. Here we identify the nucleosome acid patch as a critical chromatin mediator of H2A/H2AX ubiquitination (ub. The acidic patch is required for RNF168- and RING1B/BMI1-dependent H2A/H2AXub in vivo. The acidic patch functions within the nucleosome as nucleosomes containing a mutated acidic patch exhibit defective H2A/H2AXub by RNF168 and RING1B/BMI1 in vitro. Furthermore, direct perturbation of the nucleosome acidic patch in vivo by the expression of an engineered acidic patch interacting viral peptide, LANA, results in defective H2AXub and RNF168-dependent DNA damage responses including 53BP1 and BRCA1 recruitment to DNA damage. The acidic patch therefore is a critical nucleosome feature that may serve as a scaffold to integrate multiple ubiquitin signals on chromatin to compose selective ubiquitinations on histones for DNA damage signaling.

Radiation-induced electron migration in nucleic acids

International Nuclear Information System (INIS)

Fuciarelli, A.F.; Sisk, E.C.; Miller, J.H.; Zimbrick, J.D.

1994-01-01

Radiation-induced electron migration along DNA is a mechanism by which randomly produced stochastic energy deposition events can lead to non-random types of damage along DNA manifested distal to the sites of the initial energy deposition. Radiation-induced electron migration in nucleic acids has been examined using oligonucleotides containing 5-bromouracil (5-BrU). Interaction of 5-BrU with solvated electrons results in release of bromide ions and formation of uracil-5-yl radicals. Monitoring either bromide ion release or uracil formation provides an opportunity to study electron migration processes in model nucleic acid systems. Using this approach we have discovered that electron migration along oligonucleotides is significantly influenced by the base sequence and strandedness. Migration along 7 base pairs in oligonucleotides containing guanine bases was observed for oligonucleotides irradiated in solution, which compares with mean migration distances of 6-10 bp for Escherichia coli DNA irradiated in solution and 5.5 bp for E. coli DNA irradiated in cells. Evidence also suggests that electron migration can occur preferentially in the 5' to 3' direction along a double-stranded oligonucleotide containing a region of purine bases adjacent to the 5-BrU moiety. Our continued efforts will provide information regarding the contribution of electron transfer along DNA to formation of locally multiply damaged sites created in DNA by exposure to ionizing radiation. (Author)

4.2. The kinetics of nitric acid decomposition of calcined borosilicate raw material of Ak-Arkhar Deposit

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Kurbonov, A.S.; Mamatov, E.D.

2015-01-01

Present article is devoted to kinetics of nitric acid decomposition of calcined borosilicate raw material of Ak-Arkhar Deposit. The dependence of nitric acid decomposition of calcined boric raw material for extraction of boron oxide on temperature (20-100 deg C) and process duration (15-60 minutes) was defined. It was defined that at temperature increasing the extraction rate of boron oxide increases from 20.8 to 78.6%.

Dendrochemical evidence for soil recovery from acidic deposition in forests of the northeastern U.S. with comparisons to the southeastern U.S. and Russia

Science.gov (United States)

Walter C. Shortle; Kevin T. Smith; Andrei G. Lapenis

2017-01-01

A soil resampling approach has detected an early stage of recovery in the cation chemistry of spruce forest soil due to reductions in acid deposition. That approach is limited by the lack of soil data and archived soil samples prior to major increases in acid deposition during the latter half of the 20th century. An alternative approach is the dendrochemical analysis...

Supercritical synthesis and in situ deposition of PbS nanocrystals with oleic acid passivation for quantum dot solar cells

Energy Technology Data Exchange (ETDEWEB)

Tavakoli, M.M. [Department of Materials Science and Engineering, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of); Simchi, A., E-mail: simchi@sharif.edu [Department of Materials Science and Engineering, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of); Aashuri, H. [Department of Materials Science and Engineering, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of)

2015-04-15

Colloidal quantum dot solar cells have recently attracted significant attention due to their low-processing cost and surging photovoltaic performance. In this paper, a novel, reproducible, and simple solution-based process based on supercritical fluid toluene is presented for in situ growth and deposition PbS nanocrystals with oleic-acid passivation. A lead precursor containing sulfur was mixed with oleic acid in toluene and processed in a supercritical fluid condition at different temperatures of 140, 270 and 330 °C for 20 min. The quantum dots were deposited on a fluorine-doped tin oxide glass substrate inside the supercritical reactor. Transmission electron microscopy, X-ray diffraction, absorption and dynamic light scattering showed that the nanocrystals processed at the supercritical condition (330 °C) are fully crystalline with a narrow size distribution of ∼3 nm with an absorption wavelength of 915 nm (bandgap of 1.3 eV). Fourier transform infrared spectroscopy indicated that the PbS quantum dots are passivated by oleic acid molecules during the growth. Photovoltaic characteristics of Schottky junction solar cells showed an improvement over devices prepared by spin-coating. - Highlights: • Supercritical fluid processing and in situ deposition of PbS QDs are presented. • The prepared nanocrystals are mono-dispersed with an optical bandgap of 1.3 eV. • Photovoltaic performance of the in situ deposited nanocrystals is reported. • An improved PV performance compared to spin coated Schottky solar cells is shown.

Protective effect of 4-coumaric acid from UVB ray damage in the rabbit eye

International Nuclear Information System (INIS)

Lodovici, Maura; Caldini, Silvia; Morbidelli, Lucia; Akpan, Victor; Ziche, Marina; Dolara, Piero

2009-01-01

UV-induced oxidation damage seems to play a major role in a number of specific pathological conditions of intraocular tissues, such as cataract formation and retinal degeneration. Therefore, antioxidant and/or scavenger compounds might protect the eyes from UV-induced cellular damage. We previously reported that 4-coumaric acid (4-CA) is able to protect rabbit corneal-derived cells (SIRC) from UVB-induced oxidation damage. In this study we evaluated the protective effect of 4-CA against UVB-induced cell damage in rabbit cornea in vivo. Twelve male New Zealand albino rabbits were used; four rabbits were used as a control and received vehicle in one eye and 4-CA acid in the contralateral eye; eight rabbits were exposed to UVB rays (79.2 mJ/cm 2 ) and three days before to UV exposure each animal received 1 drop/day of vehicle in one eye and 1 drop/day of vehicle containing 4-CA (164 ng) in the contralateral eye. Corneal and sclera tissues were removed and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) levels were measured. Superoxide dismutase (SOD) and xanthine oxidase (XO) activities were determined in aqueous humour. UVB-induced vessel hyper-reactivity was strongly reduced at 4 and 24 h after UVB exposure after local treatment with 4-CA, 8-oxodGuo levels, a marker of oxidative DNA damage, were significantly increased (P < 0.05) in sclera and cornea by UVB irradiation, but when 4-CA was administered to the conjunctiva in a buffered solution once a day for 3 d before and 6 d after UVB exposure, levels of 8-oxodGuo were similar to controls and significantly reduced (P < 0.05) compared to UVB-treated corneas. XO activity in the aqueous humour was significantly increased. The administration of 4-CA for 3 d before and 6 d after UVB irradiation induced a small but significant (P < 0.05) reduction of XO compared with control eyes. Our results indicate that the administration of 4-CA protects eye tissues, thus reducing the harmful effect of UVB radiation at low

Metallization on FDM Parts Using the Chemical Deposition Technique

Directory of Open Access Journals (Sweden)

Azhar Equbal

2014-08-01

Full Text Available Metallization of ABS (acrylonitrile-butadiene-styrene parts has been studied on flat part surfaces. These parts are fabricated on an FDM (fused deposition modeling machine using the layer-wise deposition principle using ABS as a part material. Electroless copper deposition on ABS parts was performed using two different surface preparation processes, namely ABS parts prepared using chromic acid for etching and ABS parts prepared using a solution mixture of sulphuric acid and hydrogen peroxide (H2SO4/H2O2 for etching. After surface preparations using these routes, copper (Cu is deposited electrolessly using four different acidic baths. The acidic baths used are 5 wt% CuSO4 (copper sulfate with 15 wt% of individual acids, namely HF (hydrofluoric acid, H2SO4 (sulphuric acid, H3PO4 (phosphoric acid and CH3COOH (acetic acid. Cu deposition under different acidic baths used for both the routes is presented and compared based on their electrical performance, scanning electron microscopy (SEM and energy dispersive X-ray spectrometry (EDS. The result shows that chromic acid etched samples show better electrical performance and Cu deposition in comparison to samples etched via H2SO4/H2O2.

Responses of soil N-fixing bacteria communities to invasive plant species under different types of simulated acid deposition

Science.gov (United States)

Wang, Congyan; Zhou, Jiawei; Jiang, Kun; Liu, Jun; Du, Daolin

2017-06-01

Biological invasions have incurred serious threats to native ecosystems in China, and soil N-fixing bacteria communities (SNB) may play a vital role in the successful plant invasion. Meanwhile, anthropogenic acid deposition is increasing in China, which may modify or upgrade the effects that invasive plant species can cause on SNB. We analyzed the structure and diversity of SNB by means of new generation sequencing technology in soils with different simulated acid deposition (SAD), i.e., different SO4 2- to NO3 - ratios, and where the invasive ( Amaranthus retroflexus L.) and the native species ( Amaranthus tricolor L.) grew mixed or isolated for 3 months. A. retroflexus itself did not exert significant effects on the diversity and richness of SNB but did it under certain SO4 2- to NO3 - ratios. Compared to soils where the native species grew isolated, the soils where the invasive A. retroflexus grew isolated showed lower relative abundance of some SNB classes under certain SAD treatments. Some types of SAD can alter soil nutrient content which in turn could affect SNB diversity and abundance. Specifically, greater SO4 2- to NO3 - ratios tended to have more toxic effects on SNB likely due to the higher exchange capacity of hydroxyl groups (OH-) between SO4 2- and NO3 -. As a conclusion, it can be expected a change in the structure of SNB after A. retroflexus invasion under acid deposition rich in sulfuric acid. This change may create a plant soil feedback favoring future A. retroflexus invasions.

Nitrogen deposition and grass encroachment in calcareous and acidic Grey dunes (H2130) in NW-Europe

NARCIS (Netherlands)

Kooijman, A.M.; van Til, M.; Noordijk, E.; Remke, E.; Kalbitz, K.

We present an overview of high nitrogen deposition effects on coastal dune grasslands in NW-Europe (H2130), especially concerning grass encroachment in calcareous and acidic Grey Dunes. The problem is larger than previously assumed, because critical loads are still too high, and extra N-input from

Urban wet deposition nitrate: a comparison to non-urban deposition

International Nuclear Information System (INIS)

Schultz, J.A.M.

1994-01-01

The concentration of nitrate in both wet and dry deposition has both increased historically and currently, and recently parallels emissions in NO x . Since NO x is produced in amounts comparable to SO 2 , it is an important contributor to acid deposition, and is produced in higher amounts in urban areas due to concentrated sources. Prior to to this study, national acid deposition monitoring networks in the United States have been and remain established in non-urban areas. This research study consisted of a comparison of precipitation sampling and analysis of wet deposition nitrate and pH for each deposition event in each of two urban sites over a 15 mo period. Also, a comparison of urban data and data generated at a nearby non-urban NADP site was made by examination of both monthly and seasonal data. This research suggests that national monitoring programs should consider inclusion of urban and non-urban monitoring sites in order to achieve a more representative regional assessment. 24 refs., 2 figs., 2 tabs

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

International Nuclear Information System (INIS)

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

2009-01-01

Malignant transformation was demonstrated in UROtsa cells following 52-weeks of exposure to 50 nM monomethylarsonous acid (MMA 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 III [URO-MSC(+)] and after subsequent removal of MMA III [URO-MSC(-)] following chronic, low-level exposure. In the presence of MMA 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 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 III exposure, suggesting the presence of MMA 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 III results in: the induction of DNA damage that remains elevated upon removal of MMA III ; increased levels of ROS that play a role in MMA III induced-DNA damage; and decreased PARP activity in the presence of MMA III .

Application of a complex transport problem for simulating an acid rain episode in Europe. Anwendung eines komplexen Ausbreitungsmodells zur Simulation einer Episode saurer Deposition ueber Europa

Energy Technology Data Exchange (ETDEWEB)

Stern, R; Scherer, B

1989-04-01

For the first time in Europe, a comprehensive Eulerian regional tropospheric transport, transformation and removal model has been applied to an european wide acid deposition episode. This model, the Transport And Deposition of Acidifying Pollutants (TADAP) model incorporated detailed knowledge of the relevant physicochemical processes which lead to the formation of photochemical oxidants and acidifying pollutants. The EUROPA-model (EUM) of the German Weather Service, a limited area numerical weather prediction model, has been used to derive the total meteorological cloud variables. The application of the EUM/TADAP-modelling system to a 20 day-wintertime acid deposition episode in Europe showed that it is possible to model the principal features of the acid deposition system. In general, there is reasonable agreement between observed and predicted concentration and deposition patterns. Most discrepancies from observed trends can be explained by deviations between the modelled and the actual meteorology. First sensitivity studies with TADAP directed to reveal the influence of emission changes on the acid deposition system showed that there are considerable non-proportionalities between depositions of secondary pollutants and the emissions of the respective precursors. The nonlinearities arise due to the chemical coupling of the SO{sub x}/No{sub x}/VOC-system. This makes the design of control strategies to a highly complex task. Strategies developed to tackle different air pollution problems can therefore not be looked upon independently. (orig.) With 47 refs., 42 figs.

Characterization of heavy metal desorption from road-deposited sediment under acid rain scenarios.

Science.gov (United States)

Zhao, Bo; Liu, An; Wu, Guangxue; Li, Dunzhu; Guan, Yuntao

2017-01-01

Road-deposited sediments (RDS) on urban impervious surfaces are important carriers of heavy metals. Dissolved heavy metals that come from RDS influenced by acid rain, are more harmful to urban receiving water than particulate parts. RDS and its associated heavy metals were investigated at typical functional areas, including industrial, commercial and residential sites, in Guangdong, Southern China, which was an acid rain sensitive area. Total and dissolved heavy metals in five particle size fractions were analyzed using a shaking method under acid rain scenarios. Investigated heavy metals showed no difference in the proportion of dissolved fraction in the solution under different acid rain pHs above 3.0, regardless of land use. Dissolved loading of heavy metals related to organic carbon content were different in runoff from main traffic roads of three land use types. Coarse particles (>150μm) that could be efficiently removed by conventional street sweepers, accounted for 55.1%-47.1% of the total dissolved metal loading in runoff with pH3.0-5.6. The obtained findings provided a significant scientific basis to understand heavy metal release and influence of RDS grain-size distribution and land use in dissolved heavy metal pollution affected by acid rain. Copyright © 2016. Published by Elsevier B.V.

Lipoic acid in combination with a chelator ameliorates lead-induced peroxidative damages in rat kidney

Energy Technology Data Exchange (ETDEWEB)

Sivaprasad, R.; Nagaraj, M.; Varalakshmi, P. [Department of Medical Biochemistry, University of Madras (Taramani), Chennai 600 113 (India)

2002-08-01

The deleterious effect of lead has been attributed to lead-induced oxidative stress with the consequence of lipid peroxidation. The present study was designed to investigate the combined effect of DL-{alpha}-lipoic acid (LA) and meso-2,3-dimercaptosuccinic acid (DMSA) on lead-induced peroxidative damages in rat kidney. The increase in peroxidated lipids in lead-poisoned rats was accompanied by alterations in antioxidant defence systems. Lead acetate (Pb, 0.2%) was administered in drinking water for 5 weeks to induce lead toxicity. LA (25 mg/kg body weight per day i.p) and DMSA (20 mg/kg body weight per day i.p) were administered individually and also in combination during the sixth week. Nephrotoxic damage was evident from decreases in the activities of {gamma}-glutamyl transferase and N-acetyl {beta}-D-glucosaminidase, which were reversed upon combined treatment with LA and DMSA. Rats subjected to lead intoxication showed a decline in the thiol capacity of the cell, accompanied by high malondialdehyde levels along with lowered activities of catalase, superoxide dismutase, glutathione peroxidase and glutathione metabolizing enzymes (glutathione reductase, glucose-6-phosphate dehydrogenase, glutathione-S-transferase). Supplementation with LA as a sole agent showed considerable changes over oxidative stress parameters. The study has highlighted the combined effect of both drugs as being more effective in reversing oxidative damage by bringing about an improvement in the reductive status of the cell. (orig.)

Influence of hydrofluoric acid treatment on electroless deposition of Au clusters

Directory of Open Access Journals (Sweden)

Rachela G. Milazzo

2017-01-01

Full Text Available The morphology of gold nanoparticles (AuNPs deposited on a (100 silicon wafer by simple immersion in a solution containing a metal salt and hydrofluoric acid (HF is altered by HF treatment both before and after deposition. The gold clusters are characterized by the presence of flat regions and quasispherical particles consistent with the layer-by-layer or island growth modes, respectively. The cleaning procedure, including HF immersion prior to deposition, affects the predominantly occurring gold structures. Flat regions, which are of a few tens of nanometers long, are present after immersion for 10 s. The three-dimensional (3D clusters are formed after a cleaning procedure of 4 min, which results in a large amount of spherical particles with a diameter of ≈15 nm and in a small percentage of residual square layers of a few nanometers in length. The samples were also treated with HF after the deposition and we found out a general thickening of flat regions, as revealed by TEM and AFM analysis. This result is in contrast to the coalescence observed in similar experiments performed with Ag. It is suggested that the HF dissolves the silicon oxide layer formed on top of the thin flat clusters and promotes the partial atomic rearrangement of the layered gold atoms, driven by a reduction of the surface energy. The X-ray diffraction investigation indicated changes in the crystalline orientation of the flat regions, which partially lose their initially heteroepitaxial relationship with the substrate. A postdeposition HF treatment for almost 70 s has nearly the same effect of long duration, high temperature annealing. The process presented herein could be beneficial to change the spectral response of nanoparticle arrays and to improve the conversion efficiency of hybrid photovoltaic devices.

Low Protein Diet Inhibits Uric Acid Synthesis and Attenuates Renal Damage in Streptozotocin-Induced Diabetic Rats

Directory of Open Access Journals (Sweden)

Jianmin Ran

2014-01-01

Full Text Available Aim. Several studies indicated that hyperuricemia may link to the worsening of diabetic nephropathy (DN. Meanwhile, low protein diet (LPD retards exacerbation of renal damage in chronic kidney disease. We then assessed whether LPD influences uric acid metabolism and benefits the progression of DN in streptozotocin- (STZ- induced diabetic rats. Methods. STZ-induced and control rats were both fed with LPD (5% and normal protein diet (18%, respectively, for 12 weeks. Vital signs, blood and urinary samples for UA metabolism were taken and analyzed every 3 weeks. Kidneys were removed at the end of the experiment. Results. Diabetic rats developed into constantly high levels of serum UA (SUA, creatinine (SCr and 24 h amounts of urinary albumin excretion (UAE, creatintine (UCr, urea nitrogen (UUN, and uric acid (UUA. LPD significantly decreased SUA, UAE, and blood glucose, yet left SCr, UCr, and UUN unchanged. A stepwise regression showed that high UUA is an independent risk factor for DN. LPD remarkably ameliorated degrees of enlarged glomeruli, proliferated mesangial cells, and hyaline-degenerated tubular epithelial cells in diabetic rats. Expression of TNF-α in tubulointerstitium significantly decreased in LPD-fed diabetic rats. Conclusion. LPD inhibits endogenous uric acid synthesis and might accordingly attenuate renal damage in STZ-induced diabetic rats.

A new approach to assess the chemical composition of powder deposits damaging the stone surfaces of historical monuments.

Science.gov (United States)

Fermo, Paola; Turrion, Raquel Gonzalez; Rosa, Mario; Omegna, Alessandra

2015-04-01

The issue of conservation of the monumental heritage worldwide is mainly related to atmospheric pollution that causes the degradation of stone surfaces. The powder deposits present on the stone monuments reflect the composition of the aerosol particulate matter (PM) to which the surfaces are exposed, so the chemical characterization of the outermost damaged layers is necessary in order to adopt mitigation measurements to reduce PM emissions. In the present paper, a new analytical approach is proposed to investigate the chemical composition of powder deposits present on Angera stone, a dolomitic rock used in the Richini courtyard, a masterpiece of Lombard Baroque and placed in Milan. Inorganic and organic components present in these deposits have been analyzed by IC (ion chromatography) and a new approach mainly bases on thermal analyses, respectively. Gypsum is the main inorganic constituent indicating a composition similar to that of black crusts, hard black patina covering the degraded building surfaces. Ammonium nitrate present in the powder is able to react with the stone substrate to form magnesium nitrate which can migrate into the porous stone. The carbonaceous fraction powder deposits (i.e. OC = Organic Carbon and EC = Elemental Carbon) have been quantified by a new simple thermal approach based on carbon hydrogen nitrogen (CHN) analysis. The presence of high concentration of EC confirms that the powder deposits are evolving to black crust. Low values of water-soluble organic carbon (WSOC, determined by total organic carbon-TOC), with respect to what is normally found in PM, may indicate a migration process of organic substances into the stone with a worsening of the conservation conditions. The presence of heavy metals of anthropogenic origin and acting as catalysts in the black crust formation process has been highlighted by SEM-EDS (electron microscopy coupled with an energy dispersive spectrometer) as well.

Effects of multiple stresses hydropower, acid deposition and climate change on water chemistry and salmon populations in the River Otra, Norway.

Science.gov (United States)

Wright, Richard F; Couture, Raoul-Marie; Christiansen, Anne B; Guerrero, José-Luis; Kaste, Øyvind; Barlaup, Bjørn T

2017-01-01

Many surface waters in Europe suffer from the adverse effects of multiple stresses. The Otra River, southernmost Norway, is impacted by acid deposition, hydropower development and increasingly by climate change. The river holds a unique population of land-locked salmon and anadromous salmon in the lower reaches. Both populations have been severely affected by acidification. The decrease in acid deposition since the 1980s has led to partial recovery of both populations. Climate change with higher temperatures and altered precipitation can potentially further impact fish populations. We used a linked set of process-oriented models to simulate future climate, discharge, and water chemistry at five sub-catchments in the Otra river basin. Projections to year 2100 indicate that future climate change will give a small but measureable improvement in water quality, but that additional reductions in acid deposition are needed to promote full restoration of the fish communities. These results can help guide management decisions to sustain key salmon habitats and carry out effective long-term mitigation strategies such as liming. The Otra River is typical of many rivers in Europe in that it fails to achieve the good ecological status target of the EU Water Framework Directive. The programme of measures needed in the river basin management plan necessarily must consider the multiple stressors of acid deposition, hydropower, and climate change. This is difficult, however, as the synergistic and antagonistic effects are complex and challenging to address with modelling tools currently available. Copyright © 2016 Elsevier B.V. All rights reserved.

Vacuum thermal evaporation of polyaniline doped with camphor sulfonic acid

Energy Technology Data Exchange (ETDEWEB)

Boyne, Devon; Menegazzo, Nicola; Pupillo, Rachel C.; Rosenthal, Joel; Booksh, Karl S., E-mail: kbooksh@udel.edu [Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716 (United States)

2015-05-15

Intrinsically conducting polymers belong to a class of organic polymers with intriguing electronic and physical properties specifically for electro-optical applications. Significant interest into doped polyaniline (PAni) can be attributed to its high conductivity and environmental stability. Poor dissolution in most solvents has thus far hindered the successful integration of PAni into commercial applications, which in turn, has led to the investigations of various deposition and acidic doping methods. Physical vapor deposition methods, including D.C. magnetron sputtering and vacuum thermal evaporation, have shown exceptional control over physical film properties (thickness and morphology). However, resulting films are less conductive than films deposited by conventional methods (i.e., spin and drop casting) due to interruption of the hyperconjugation of polymer chains. Specifically, vacuum thermal evaporation requires a postdoping process, which results in incorporation of impurities and oxidation of surface moieties. In this contribution, thermally evaporated films, sequentially doped by vacuum evaporation of an organic acid (camphorsulfonic acid, CSA) is explored. Spectroscopic evidence confirms the successful doping of PAni with CSA while physical characterization (atomic force microscopy) suggests films retain good morphology and are not damaged by the doping process. The procedure presented herein also combines other postpreparation methods in an attempt to improve conductivity and/or substrate adhesion.

Effects of acid deposition on dissolution of carbonate stone during summer storms in the Adirondack Mountains, New York, 1987-89

Science.gov (United States)

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

Amelioration of both early and late radiation-induced damage to pig skin by essential fatty acids

International Nuclear Information System (INIS)

Hopewell, J.W.; Van den Aardweg, G.J.M.J.; Morris, G.M.

1994-01-01

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 β-rays from 22.5 mm diameter 90 Sr/ 90 Y plaques at a dose rate of ∼3 Gy/min. Essential fatty acids were administered orally in the form of two open-quotes activeclose 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 placeboclose 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 activeclose 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 β-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

Is Branched-Chain Amino Acids Supplementation an Efficient Nutritional Strategy to Alleviate Skeletal Muscle Damage? A Systematic Review

Directory of Open Access Journals (Sweden)

Alexandre Fouré

2017-09-01

Full Text Available Amino acids and more precisely, branched-chain amino acids (BCAAs, are usually consumed as nutritional supplements by many athletes and people involved in regular and moderate physical activities regardless of their practice level. BCAAs have been initially shown to increase muscle mass and have also been implicated in the limitation of structural and metabolic alterations associated with exercise damage. This systematic review provides a comprehensive analysis of the literature regarding the beneficial effects of BCAAs supplementation within the context of exercise-induced muscle damage or muscle injury. The potential benefit of a BCAAs supplementation was also analyzed according to the supplementation strategy—amount of BCAAs, frequency and duration of the supplementation—and the extent of muscle damage. The review protocol was registered prospectively with Prospective Register for Systematic Reviews (registration number CRD42017073006 and followed Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Literature search was performed from the date of commencement until August 2017 using four online databases (Medline, Cochrane library, Web of science and ScienceDirect. Original research articles: (i written in English; (ii describing experiments performed in Humans who received at least one oral BCAAs supplementation composed of leucine, isoleucine and valine mixture only as a nutritional strategy and (iii reporting a follow-up of at least one day after exercise-induced muscle damage, were included in the systematic review analysis. Quality assessment was undertaken independently using the Quality Criteria Checklist for Primary Research. Changes in indirect markers of muscle damage were considered as primary outcome measures. Secondary outcome measures were the extent of change in indirect markers of muscle damage. In total, 11 studies were included in the analysis. A high heterogeneity was found regarding the

Changes in LDL fatty acid composition as a response to olive oil treatment are inversely related to lipid oxidative damage: The EUROLIVE study

DEFF Research Database (Denmark)

Cicero, Arrigo F G; Nascetti, Simona; López-Sabater, Maria C

2008-01-01

The aim of our study was to assess the changes in the fatty acid composition of low density lipoproteins (LDL) after sustained consumption of olive oil at real-life doses (25 mL/day) and their relationship with lipid oxidative damage.......The aim of our study was to assess the changes in the fatty acid composition of low density lipoproteins (LDL) after sustained consumption of olive oil at real-life doses (25 mL/day) and their relationship with lipid oxidative damage....

Comparison of gate dielectric plasma damage from plasma-enhanced atomic layer deposited and magnetron sputtered TiN metal gates

Energy Technology Data Exchange (ETDEWEB)

Brennan, Christopher J.; Neumann, Christopher M.; Vitale, Steven A., E-mail: steven.vitale@ll.mit.edu [Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts 02420 (United States)

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.

USGS Tracks Acid Rain

Science.gov (United States)

Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

1995-01-01

The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

Prostacyclin production in rabbit arteries in situ: inhibition by arachidonic acid-induced endothelial cell damage or by low-dose aspirin.

Science.gov (United States)

Ingerman-Wojenski, C; Silver, M J; Smith, J B; Nissenbaum, M; Sedar, A W

1981-04-01

The central artery of the rabbit ear was perfused in situ and effluent fractions from the artery were assayed for 6-keto-prostaglandin F1 alpha (6-K-PGF1 alpha) and thromboxane B2 (TxB2), the stable metabolites of prostacyclin (PGI2) and TxA2, using specific radioimmunoassays. These metabolites of arachidonic acid (AA) were not detected in the effluent during infusion of Tyrode's solution but both metabolites were detected when small amounts of AA were infused into the artery. Examination of the arteries by scanning electron microscopy revealed that high concentrations of AA which caused a short burst of 6-K-PGF1 alpha and TxB2 production damaged the endothelial cells while lower concentrations which stimulated continuous production did not cause damage. When a non-damaging concentration of AA was infused into an artery that had previously received a damaging concentration, PG production was greatly reduced. Pretreatment of the rabbits with 4 mg/kg acetyl-salicylic acid (ASA) inhibited 6-K-PGF1 alpha production by the rabbit ear artery in response to AA and 70% inhibition was still evident 18 hours after ASA.

Characterization of damaging in apatitic materials irradiated with heavy ions and thermally annealed

International Nuclear Information System (INIS)

Tisserand, R.

2004-12-01

Some minerals belonging to the family of apatite are seen to be potential candidates for use as conditioning matrices or transmutation targets for high level nuclear waste management. Indeed, studies of natural nuclear reactors (Oklo) highlighted the strong ability of these minerals to anneal irradiation damage. In order to determine the global behaviour of these materials, we performed a fundamental study on the evolution of irradiation damage induced by various heavy ions in two apatites: a natural phospho-calcic fluor-apatite from Durango and a synthetic sintered mono-silicated fluor-apatite, called britholite. The damage in these materials was measured by using channelling R.B.S. and X-ray diffraction respectively and by determining an amorphization effective radius Re. The results revealed a similar behaviour for both apatites according to the electronic energy deposit at the entrance of the material. In addition, the effect of an isothermal annealing at 300 C was quantified on a mono-silicated britholite previously irradiated with Kr ions. We highlighted in this case the return of the lattice parameters to their initial values, followed by a partial and slow rebuilding of the crystalline lattice versus the annealing time. Finally, we followed the changes in the morphology of etch pits in the Durango fluor-apatite after acid dissolution as a function of the energy deposit by the ions. We showed that the influence of crystallography leads quickly to opening angles close to 30 degrees. The calculation of etching velocities within the irradiated material highlighted that there is a range of deposit energy where the velocity ratio increases strongly before becoming constant. (author)

National Acid Precipitation Assessment Program Report to Congress: An Integrated Assessment

Energy Technology Data Exchange (ETDEWEB)

Uhart, M.; et al,

2005-08-01

Under Title IX of the 1990 Clean Air Act Amendments, Congress reauthorized the National Acid Precipitation Assessment Program (NAPAP) to continue coordinating acid rain research and monitoring, as it had done during the previous decade, and to provide Congress with periodic reports. In particular, Congress asked NAPAP to assess all available data and information to answer two questions: (1) What are the costs, benefits, and effectiveness of Title IV? This question addresses the costs and economic impacts of complying with the Acid Rain Program as well as benefit analyses associated with the various human health and welfare effects, including reduced visibility, damages to materials and cultural resources, and effects on ecosystems. (2) What reductions in deposition rates are needed to prevent adverse ecological effects? This complex questions addresses ecological systems and the deposition levels at which they experience harmful effects. The results of the assessment of the effects of Title IV and of the relationship between acid deposition rates and ecological effects were to be reported to Congress quadrennially, beginning with the 1996 report to Congress. The objective of this Report is to address the two main questions posed by Congress and fully communicate the results of the assessment to decision-makers. Given the primary audience, most of this report is not written as a technical document, although information supporting the conclusions is provided along with references.

Analysis of laser energy deposition leading to damage and ablation of HfO{sub 2} and Nb{sub 2}O{sub 5} single layers submitted to 500 fs pulses at 1030 and 343 nm

Energy Technology Data Exchange (ETDEWEB)

Douti, Dam-Be; Begou, Thomas; Lemarchand, Fabien; Lumeau, Julien; Commandre, Mireille; Gallais, Laurent [Aix-Marseille Universite, CNRS, Centrale Marseille, Institut Fresnel UMR 7249, Marseille (France)

2016-07-15

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. (orig.)

Progress Toward Meeting NIF Specifications for Vapor Deposited Polyimide Ablator Coatings

International Nuclear Information System (INIS)

Letts, Stephan A.; Anthamatten, Mitchell; Buckley, Steven R.; Fearon, Evelyn; Nissen, April E.H.; Cook, Robert C.

2004-01-01

We are developing an evaporative coating technique for deposition of thick polyimide (PI) ablator layers on ICF targets. The PI coating technique utilizes stoichiometrically controlled fluxes from two Knudsen cell evaporators containing a dianhydride and a diamine to deposit a polyamic acid (PAA) coating. Heating the PAA coating to 300 deg. C converts the PAA coating to a polyimide. Coated shells are rough due to particles on the substrate mandrels and from damage to the coating caused by the agitation used to achieve a uniform coating. We have developed a smoothing process that exposes an initially rough PAA coated shell to solvent vapor using gas levitation. We found that after smoothing the coatings developed a number of wide (low-mode) defects. We have identified two major contributors to low-mode roughness: surface hydrolysis, and deformation during drying/curing. By minimizing air exposure prior to vapor smoothing, avoiding excess solvent sorption during vapor smoothing, and using slow drying we are able to deposit and vapor smooth coatings 160 μm thick with a surface roughness less than 20 nm RMS

The omega-3 fatty acid, eicosapentaenoic acid (EPA, prevents the damaging effects of tumour necrosis factor (TNF-alpha during murine skeletal muscle cell differentiation

Directory of Open Access Journals (Sweden)

Pearson Stephen

2008-07-01

Full Text Available Abstract Background Eicosapentaenoic acid (EPA is a ώ-3 polyunsaturated fatty acid with anti-inflammatory and anti-cachetic properties that may have potential benefits with regards to skeletal muscle atrophy conditions where inflammation is present. It is also reported that pathologic levels of the pro-inflammatory cytokine tumour necrosis factor (TNF-α are associated with muscle wasting, exerted through inhibition of myogenic differentiation and enhanced apoptosis. These findings led us to hypothesize that EPA may have a protective effect against skeletal muscle damage induced by the actions of TNF-α. Results The deleterious effects of TNF-α on C2C12 myogenesis were completely inhibited by co-treatment with EPA. Thus, EPA prevented the TNF-mediated loss of MyHC expression and significantly increased myogenic fusion (p p p p p p Conclusion In conclusion, EPA has a protective action against the damaging effects of TNF-α on C2C12 myogenesis. These findings support further investigations of EPA as a potential therapeutic agent during skeletal muscle regeneration following injury.

Ester Sensing with Poly (Aniline-co-m-aminobenzoic Acid Deposited on Poly (Vinyl Alcohol

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S. ADHIKARI

2011-02-01

Full Text Available Poly (aniline-co-m-aminobenzoic acid was deposited on poly (vinyl alcohol film by in situ oxidative polymerization of the monomers aniline and m-aminobenzoic acid. Sensing experiments were performed on the composite film with the injection of various concentrations of hexenyl acetate and hexenyl butyrate at room temperature. The sensor responded rapidly and reversibly in the presence of hexenyl acetate and hexenyl butyrate vapors which was detected by resistance change of the composite film upon exposure to the vapor. Selectivity tests revealed that the sensor selectively responded to hexenyl butyrate compared to hexenyl acetate. The sensing response has been explained on the basis of FT-IR spectroscopic analysis of the polymer film before and after exposure to the ester vapor.

Alkali production associated with malolactic fermentation by oral streptococci and protection against acid, oxidative, or starvation damage.

Science.gov (United States)

Sheng, Jiangyun; Baldeck, Jeremiah D; Nguyen, Phuong T M; Quivey, Robert G; Marquis, Robert E

2010-07-01

Alkali production by oral streptococci is considered important for dental plaque ecology and caries moderation. Recently, malolactic fermentation (MLF) was identified as a major system for alkali production by oral streptococci, including Streptococcus mutans. Our major objectives in the work described in this paper were to further define the physiology and genetics of MLF of oral streptococci and its roles in protection against metabolic stress damage. L-Malic acid was rapidly fermented to L-lactic acid and CO(2) by induced cells of wild-type S. mutans, but not by deletion mutants for mleS (malolactic enzyme) or mleP (malate permease). Mutants for mleR (the contiguous regulator gene) had intermediate capacities for MLF. Loss of capacity to catalyze MLF resulted in loss of capacity for protection against lethal acidification. MLF was also found to be protective against oxidative and starvation damage. The capacity of S. mutans to produce alkali from malate was greater than its capacity to produce acid from glycolysis at low pH values of 4 or 5. MLF acted additively with the arginine deiminase system for alkali production by Streptococcus sanguinis, but not with urease of Streptococcus salivarius. Malolactic fermentation is clearly a major process for alkali generation by oral streptococci and for protection against environmental stresses.

Alkali production associated with malolactic fermentation by oral streptococci and protection against acid, oxidative, or starvation damage

Science.gov (United States)

Sheng, Jiangyun; Baldeck, Jeremiah D.; Nguyen, Phuong T.M.; Quivey, Robert G.; Marquis, Robert E.

2011-01-01

Alkali production by oral streptococci is considered important for dental plaque ecology and caries moderation. Recently, malolactic fermentation (MLF) was identified as a major system for alkali production by oral streptococci, including Streptococcus mutans. Our major objectives in the work described in this paper were to further define the physiology and genetics of MLF of oral streptococci and its roles in protection against metabolic stress damage. l-Malic acid was rapidly fermented to l-lactic acid and CO2 by induced cells of wild-type S. mutans, but not by deletion mutants for mleS (malolactic enzyme) or mleP (malate permease). Mutants for mleR (the contiguous regulator gene) had intermediate capacities for MLF. Loss of capacity to catalyze MLF resulted in loss of capacity for protection against lethal acidification. MLF was also found to be protective against oxidative and starvation damage. The capacity of S. mutans to produce alkali from malate was greater than its capacity to produce acid from glycolysis at low pH values of 4 or 5. MLF acted additively with the arginine deiminase system for alkali production by Streptococcus sanguinis, but not with urease of Streptococcus salivarius. Malolactic fermentation is clearly a major process for alkali generation by oral streptococci and for protection against environmental stresses. PMID:20651853

Fat, oil and grease deposits in sewers: characterisation of deposits and formation mechanisms.

Science.gov (United States)

Williams, J B; Clarkson, C; Mant, C; Drinkwater, A; May, E

2012-12-01

Fat, oil and grease deposits (FOG) in sewers are a major problem and can cause sewer overflows, resulting in environmental damage and health risks. Often simplistically portrayed as cooling of fats, recent research has suggested that saponification may be involved in FOG formation. However there are still questions about the mechanisms effecting transformations in sewers and the role and source of metal cations involved in saponification. This study characterises FOG deposits from pumping stations, sewers and sewage works from different water hardness zones across the UK. The sites all had previous problems with FOG and most catchments contained catering and food preparation establishments. The FOG deposits were highly variable with moisture content ranging from 15 to 95% and oil content from 0 to 548 mg/g. Generally the pumping stations had lower moisture content and higher fat content, followed by the sewers then the sewage works. The water in contact with the FOG had high levels of oil (mean of about 800 mg/L) and this may indicate poor kitchen FOG management practices. FOG fatty acid profiles showed a transformation from unsaturated to saturated forms compared to typical cooking oils. This seems to relate to ageing in the sewer network or the mechanism of formation, as samples from pumping stations had higher proportions of C18:1 compared to C16. This may be due to microbial transformations by bacteria such as Clostridium sp. in a similar process to adipocere formation. There was an association between water hardness and increased Ca levels in FOG along with harder deposits and higher melting points. A link between FOG properties and water hardness has not been previously reported for field samples. This may also be due to microbial processes, such as biocalcification. By developing the understanding of these mechanisms it may be possible to more effectively control FOG deposits, especially when combined with promotion of behavioural change. Copyright © 2012

No effect of short-term amino acid supplementation on variables related to skeletal muscle damage in 100 km ultra-runners - a randomized controlled trial

Directory of Open Access Journals (Sweden)

Rosemann Thomas

2011-04-01

Full Text Available Abstract 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.

Damage of guinea pig heart and arteries by a trioleate-enriched diet and of cultured cardiomyocytes by oleic acid.

Directory of Open Access Journals (Sweden)

Josef Krieglstein

2010-03-01

Full Text Available Mono-unsaturated fatty acids (MUFAs like oleic acid have been shown to cause apoptosis of cultured endothelial cells by activating protein phosphatase type 2C alpha and beta (PP2C. The question arises whether damage of endothelial or other cells could be observed in intact animals fed with a trioleate-enriched diet.Dunkin-Hartley guinea pigs were fed with a trioleate-enriched diet for 5 months. Advanced atherosclerotic changes of the aorta and the coronary arteries could not be seen but the arteries appeared in a pre-atherosclerotic stage of vascular remodelling. However, the weight and size of the hearts were lower than in controls and the number of apoptotic myocytes increased in the hearts of trioleate-fed animals. To confirm the idea that oleic acid may have caused this apoptosis by activation of PP2C, cultured cardiomyocytes from guinea pigs and mice were treated with various lipids. It was demonstrable that oleic acid dose-dependently caused apoptosis of cardiomyocytes from both species, yet, similar to previous experiments with cultured neurons and endothelial cells, stearic acid, elaidic acid and oleic acid methylester did not. The apoptotic effect caused by oleic acid was diminished when PP2C alpha and beta were downregulated by siRNA showing that PP2C was causally involved in apoptosis caused by oleic acid.The glycerol trioleate diet given to guinea pigs for 5 months did not cause marked atherosclerosis but clearly damaged the hearts by activating PP2C alpha and beta. The diet used with 24% (wt/wt glycerol trioleate is not comparable to human diets. The detrimental role of MUFAs for guinea pig heart tissue in vivo is shown for the first time. Whether it is true for humans remains to be shown.

Impact of the Fused Deposition (FDM) Printing Process on Polylactic Acid (PLA) Chemistry and Structure

OpenAIRE

Michael Arthur Cuiffo; Jeffrey Snyder; Alicia M. Elliott; Nicholas Romero; Sandhiya Kannan; Gary P. Halada

2017-01-01

Polylactic acid (PLA) is an organic polymer commonly used in fused deposition (FDM) printing and biomedical scaffolding that is biocompatible and immunologically inert. However, variations in source material quality and chemistry make it necessary to characterize the filament and determine potential changes in chemistry occurring as a result of the FDM process. We used several spectroscopic techniques, including laser confocal microscopy, Fourier transform infrared (FTIR) spectroscopy and pho...

Heat deposition, damage, and tritium breeding characteristics in thick liquid wall blanket concepts

International Nuclear Information System (INIS)

Youssef, M.Z.; Abdou, M.A.

2000-01-01

The advanced power extraction (APEX) study aims at exploring new and innovative blanket concepts that can efficiently extract power from fusion devices with high neutron wall load. Among the concepts under investigation is the free liquid FW/liquid blanket concept in which a fast flowing liquid FW (∼2-3 cm) is followed by thick flowing blanket (B) of ∼40-50 cm thickness with minimal amount of structure. The liquid FW/B are contained inside the vacuum vessel (VV) with a shielding zone (S) located either behind the VV and outside the vacuum boundary (case A) or placed after the FW/B and inside the VV (case B). In this paper we investigate the nuclear characteristics of this concept in terms of: (1) attenuation capability of the liquid FW/B/S and protection of the VV and magnet against radiation damage; (2) profiles of tritium production rate and tritium breeding ratio (TBR) for several liquid candidates; and (3) profiles of heat deposition rate and power multiplication. The candidate liquid breeders considered are Li, Flibe, Li-Sn, and Li-Pb. Parameters varied are (1) FW/B thickness, L, (2) Li-6 enrichment and (3) thickness of the shield

The impact of acid deposition and forest harvesting on lakes and their forested catchments in south central Ontario: a critical loads approach

Directory of Open Access Journals (Sweden)

S. A. Watmough

2002-01-01

Full Text Available The impact of acid deposition and tree harvesting on three lakes and their representative sub-catchments in the Muskoka-Haliburton region of south-central Ontario was assessed using a critical loads approach. As nitrogen dynamics in forest soils are complex and poorly understood, for simplicity and to allow comparison among lakes and their catchments, CLs (A for both lakes and forest soils were calculated assuming that nitrate leaching from catchments will not change over time (i.e. a best case scenario. In addition, because soils in the region are shallow, base cation weathering rates for the representative sub-catchments were calculated for the entire soil profile and these estimates were also used to calculate critical loads for the lakes. These results were compared with critical loads obtained by the Steady State Water Chemistry (SSWC model. Using the SSWC model, critical loads for lakes were between 7 and 19 meq m-2yr-1 higher than those obtained from soil measurements. Lakes and forests are much more sensitive to acid deposition if forests are harvested, but two acid-sensitive lakes had much lower critical loads than their respective forested sub-catchments implying that acceptable acid deposition levels should be dictated by the most acid-sensitive lakes in the region. Under conditions that assume harvesting, the CL (A is exceeded at two of the three lakes and five of the six sub-catchments assessed in this study. However, sulphate export from catchments greatly exceeds input in bulk deposition and, to prevent lakes from falling below the critical chemical limit, sulphate inputs to lakes must be reduced by between 37% and 92% if forests are harvested. Similarly, sulphate leaching from forested catchments that are harvested must be reduced by between 16 and 79% to prevent the ANC of water draining the rooting zone from falling below 0 μeq l-1. These calculations assume that extremely low calcium leaching losses (9–27 μeq l-1 from

Inhibitors of acid secretion can benefit gastric wound repair independent of luminal pH effects on the site of damage

Science.gov (United States)

Demitrack, Elise S; Aihara, Eitaro; Kenny, Susan; Varro, Andrea; Montrose, Marshall H

2012-01-01

Background and aims The authors’ goal was to measure pH at the gastric surface (pHo) to understand how acid secretion affects the repair of microscopic injury to the gastric epithelium. Methods Microscopic gastric damage was induced by laser light, during confocal/two-photon imaging of pH-sensitive dyes (Cl-NERF, BCECF) that were superfused over the mucosal surface of the exposed gastric corpus of anaesthetised mice. The progression of repair was measured in parallel with pHo. Experimental conditions included varying pH of luminal superfusates, and using omeprazole (60 mg/kg ip) or famotidine (30 mg/kg ip) to inhibit acid secretion. Results Similar rates of epithelial repair and resting pHo values (~pH 4) were reported in the presence of luminal pH 3 or pH 5. Epithelial repair was unreliable at luminal pH 2 and pHo was lower (2.5±0.2, P pH 3). Epithelial repair was slower at luminal pH 7 and pHo was higher (6.4±0.1, PpH 3 or pH 7, omeprazole reduced maximal damage size and accelerated epithelial repair, although only at pH 3 did omeprazole further increase surface pH above the level caused by imposed damage. At luminal pH 7, famotidine also reduced maximal damage size and accelerated epithelial repair. Neither famotidine nor omeprazole raised plasma gastrin levels during the time course of the experiments. Conclusions Epithelial repair in vivo is affected by luminal pH variation, but the beneficial effects of acutely blocking acid secretion extend beyond simply raising luminal and/or surface pH. PMID:21997560

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

Energy Technology Data Exchange (ETDEWEB)

Rezaee, Mohammad, E-mail: Mohammad.Rezaee@USherbrooke.ca; Hunting, Darel J.; Sanche, Léon [Groupe en Sciences des Radiations, Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4 (Canada)

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

Atomic-Layer-Deposited Transparent Electrodes for Silicon Heterojunction Solar Cells

International Nuclear Information System (INIS)

Demaurex, Benedicte; Seif, Johannes P.; Smit, Sjoerd; Macco, Bart; Kessels, W. M.; Geissbuhler, Jonas; De Wolf, Stefaan; Ballif, Christophe

2014-01-01

We examine damage-free transparent-electrode deposition to fabricate high-efficiency amorphous silicon/crystalline silicon heterojunction solar cells. Such solar cells usually feature sputtered transparent electrodes, the deposition of which may damage the layers underneath. Using atomic layer deposition, we insert thin protective films between the amorphous silicon layers and sputtered contacts and investigate their effect on device operation. We find that a 20-nm-thick protective layer suffices to preserve, unchanged, the amorphous silicon layers beneath. Insertion of such protective atomic-layer-deposited layers yields slightly higher internal voltages at low carrier injection levels. However, we identify the presence of a silicon oxide layer, formed during processing, between the amorphous silicon and the atomic-layer-deposited transparent electrode that acts as a barrier, impeding hole and electron collection

Stream chemistry in the eastern United States. 2. Current sources of acidity in acidic and low acid-neutralizing-capacity streams

International Nuclear Information System (INIS)

Herlihy, A.T.; Kaufmann, P.R.; Mitch, M.E.

1991-01-01

The authors examined anion composition in National Stream Survey (NSS) data in order to evaluate the most probable sources of current acidity in acidic and low acid neutralizing capacity (ANC) streams in the eastern United States. Acidic streams that had almost no organic influence (less than 10% of total anions) and sulfate and nitrate concentrations indicative of evaporative concentration of atmospheric deposition were classified as acidic due to acidic deposition. These acidic streams were located in small forested watersheds in the Mid-Atlantic Highlands (an estimated 1950 km of stream length) and in the Mid-Atlantic Coastal Plain (1250 km). Acidic streams affected primarily by acidic deposition but also influenced by naturally occurring organic anions accounted for another 1180 km of acidic stream length and were located in the New Jersey Pine Barrens, plateau tops in the Mid-Atlantic and Southeast Highlands, and the Florida Panhandle. The total length of streams acidic due to acid mine drainage in the NSS (4590 km) was about the same as the total length of acidic streams likely affected by acidic deposition (4380 km). Acidic streams whose acid anion composition was dominated by organics were located in Florida and the Mid-Atlantic Coastal Plain. In Florida, most of the acidic streams were organic dominated, whereas about half of the streams in the Mid-Atlantic Coastal Plain were organic dominated. Organic-dominated acidic streams were not observed in the Mid-Atlantic and Southeast Highlands

Protective effects of rosmarinic acid on sepsis-induced DNA damage in the liver of Wistar albino rats

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Hatice Gul Goktas

2015-06-01

Full Text Available Sepsis is an imbalance between pro and anti-inflammatory responses. Sepsis induced multiple organ failure that is associated with mortality is characterized by liver, renal, cardiovascular and pulmonary dysfunction and reactive oxygen species (ROS are believed to be involved in the development of sepsis. Plant polyphenols may act as antioxidants by different mechanisms such as free radical scavenging, metal chelation and protein binding. Data indicates possible beneficial effects of plant derived phenolic compounds against sepsis. Rosmarinic acid (RA (α-O-caffeoyl-3,4-dihydroxyphenyllactic acid is a phenolic compound commonly found in various plants such as Rosmarinus officinalis (rosemary, Origanum vulgare (oregano, Thymus vulgaris (thyme, Mentha spicata (spearmint, Perilla frutescens (perilla, Ocimum basilicum (sweet basil and several other medicinal plants. It has been shown that RA has many biological activities including antioxidant, anti-inflammatory, antiallergic, anticancer and actimicrobial and is widely used in cosmetic and food industry. In the present study, we aimed to determine the protective effects of RA against the oxidative DNA damage induced by sepsis in Wistar albino rats. The rats were divided into four groups; sham, sepsis induced, RA-treated, RA treated and sepsis induced groups. Wistar rats were subjected to sepsis by cecal ligation puncture. The liver tissues were carefully dissected from their attachments and totally excised. The concentrations of the hepatic tissue cells were adjusted to approximately 2 x 106 cells/ml. Standard and formamidopyrimidine-DNA glycosylase (Fpg modified comet assay described by Singh et al were used. There were no statistically significant differences in terms of tail length, tail intensity and tail moment between the sham group and the RA-treated groups (p>0.05. The DNA damage was found significantly higher in the sepsis-induced group compared to the sham group (p0.05, and the DNA damage

Quantitative assessment of the ion-beam irradiation induced direct damage of nucleic acid bases through FTIR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Huang, Qing, E-mail: huangq@ipp.ac.cn [Key Laboratory of Ion Beam Bio-engineering, Institute of Technical Biology and Agriculture Engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); University of Science and Technology of China, Hefei 230029, Anhui (China); Su, Xi; Yao, Guohua; Lu, Yilin; Ke, Zhigang; Liu, Jinghua; Wu, Yuejin; Yu, Zengliang [Key Laboratory of Ion Beam Bio-engineering, Institute of Technical Biology and Agriculture Engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China)

2014-07-01

Energetic particles exist ubiquitously in nature, and when they hit DNA molecules in organisms, they may induce critical biological effects such as mutation. It is however still a challenge to measure directly and quantitatively the damage imposed by the energetic ions on target DNA molecules. In this work we attempted to employ Fourier transformation infrared (FTIR) spectroscopy to assess the ion-induced direct damage of four nucleic acid bases, namely, thymine (T), cytosine (C), guanine (G), and adenine (A), which are the building blocks of DNA molecules. The samples were prepared as thin films, irradiated by argon ion-beams at raised ion fluences, and in the meantime measured by FTIR spectroscopy for the damage in a quasi-in-situ manner. It was found that the low-energy ion-beam induced radiosensitivity of the four bases shows the sequence G > T > C > A, wherein the possible mechanism was also discussed.

Effects of Acidic Deposition and Soil Acidification on Sugar Maple Trees in the Adirondack Mountains, New York

Science.gov (United States)

T. J. Sullivan; G. B. Lawrence; S. W. Bailey; T. C. McDonnell; C. M. Beier; K. C. Weathers; G. T. McPherson; D. A. Bishop

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...

Evidence for fat, oil, and grease (FOG) deposit formation mechanisms in sewer lines.

Science.gov (United States)

He, Xia; Iasmin, Mahbuba; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J; de los Reyes, Francis L

2011-05-15

The presence of hardened and insoluble fats, oil, and grease (FOG) deposits in sewer lines is a major cause of line blockages leading to sanitary sewer overflows (SSOs). Despite the central role that FOG deposits play in SSOs, little is known about the mechanisms of FOG deposit formation in sanitary sewers. In this study, FOG deposits were formed under laboratory conditions from the reaction between free fatty acids and calcium chloride. The calcium and fatty acid profile analysis showed that the laboratory-produced FOG deposit displayed similar characteristics to FOG deposits collected from sanitary sewer lines. Results of FTIR analysis showed that the FOG deposits are metallic salts of fatty acid as revealed by comparisons with FOG deposits collected from sewer lines and pure calcium soaps. Based on the data, we propose that the formation of FOG deposits occurs from the aggregation of excess calcium compressing the double layer of free fatty acid micelles and a saponification reaction between aggregated calcium and free fatty acids.

BDS thin film damage competition

Science.gov (United States)

Stolz, Christopher J.; Thomas, Michael D.; Griffin, Andrew J.

2008-10-01

A laser damage competition was held at the 2008 Boulder Damage Symposium in order to determine the current status of thin film laser resistance within the private, academic, and government sectors. This damage competition allows a direct comparison of the current state-of-the-art of high laser resistance coatings since they are all tested using the same damage test setup and the same protocol. A normal incidence high reflector multilayer coating was selected at a wavelength of 1064 nm. The substrates were provided by the submitters. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials, and layer count will also be shared.

Prevention of iron- and copper-mediated DNA damage by catecholamine and amino acid neurotransmitters, L-DOPA, and curcumin: metal binding as a general antioxidant mechanism.

Science.gov (United States)

García, Carla R; Angelé-Martínez, Carlos; Wilkes, Jenna A; Wang, Hsiao C; Battin, Erin E; Brumaghim, Julia L

2012-06-07

Concentrations of labile iron and copper are elevated in patients with neurological disorders, causing interest in metal-neurotransmitter interactions. Catecholamine (dopamine, epinephrine, and norepinephrine) and amino acid (glycine, glutamate, and 4-aminobutyrate) neurotransmitters are antioxidants also known to bind metal ions. To investigate the role of metal binding as an antioxidant mechanism for these neurotransmitters, L-dihydroxyphenylalanine (L-DOPA), and curcumin, their abilities to prevent iron- and copper-mediated DNA damage were quantified, cyclic voltammetry was used to determine the relationship between their redox potentials and DNA damage prevention, and UV-vis studies were conducted to determine iron and copper binding as well as iron oxidation rates. In contrast to amino acid neurotransmitters, catecholamine neurotransmitters, L-DOPA, and curcumin prevent significant iron-mediated DNA damage (IC(50) values of 3.2 to 18 μM) and are electrochemically active. However, glycine and glutamate are more effective at preventing copper-mediated DNA damage (IC(50) values of 35 and 12.9 μM, respectively) than L-DOPA, the only catecholamine to prevent this damage (IC(50) = 73 μM). This metal-mediated DNA damage prevention is directly related to the metal-binding behaviour of these compounds. When bound to iron or copper, the catecholamines, amino acids, and curcumin significantly shift iron oxidation potentials and stabilize Fe(3+) over Fe(2+) and Cu(2+) over Cu(+), a factor that may prevent metal redox cycling in vivo. These results highlight the disparate antioxidant activities of neurotransmitters, drugs, and supplements and highlight the importance of considering metal binding when identifying antioxidants to treat and prevent neurodegenerative disorders.

Protein and lipid deposition rates in male broiler chickens : separate responses to amino acids and protein-free energy

NARCIS (Netherlands)

Eits, R.M.; Kwakkel, R.P.; Verstegen, M.W.A.; Stoutjesdijk, P.; Greef, de K.H.

2002-01-01

Two experiments of similar design were conducted with male broiler chickens over two body weight ranges, 200 to 800 g in Experiment 1 and 800 to 1,600 g in Experiment 2. The data were used to test the hypothesis that protein deposition rate increases (linearly) with increasing amino acid intake,

Danburite decomposition by hydrochloric acid

International Nuclear Information System (INIS)

Mamatov, E.D.; Ashurov, N.A.; Mirsaidov, U.

2011-01-01

Present article is devoted to decomposition of danburite of Ak-Arkhar Deposit of Tajikistan by hydrochloric acid. The interaction of boron containing ores of Ak-Arkhar Deposit of Tajikistan with mineral acids, including hydrochloric acid was studied. The optimal conditions of extraction of valuable components from danburite composition were determined. The chemical composition of danburite of Ak-Arkhar Deposit was determined as well. The kinetics of decomposition of calcined danburite by hydrochloric acid was studied. The apparent activation energy of the process of danburite decomposition by hydrochloric acid was calculated.

Leaching of cell wall components caused by acid deposition on fir needles and trees

Energy Technology Data Exchange (ETDEWEB)

Shigihara, Ado [Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan)], E-mail: r200670202@kanagawa-u.ac.jp; Matsumoto, Kiyoshi [Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan); Sakurai, Naoki [Faculty of Integrated Arts and Science, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, 739-8521 (Japan); Igawa, Manabu [Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan)

2008-07-15

Virgin fir forests have been declining since the 1960s at Mt. Oyama, which is located at the eastern edge of the Tanzawa Mountains and adjacent to the Kanto plain in Japan. An acid fog frequently occurs in the mountains. We collected throughfall and stemflow under fir trees and rainfall every week during January-December 2004 at Mt. Oyama to clarify the influence of acid fog on the decline of fir (Abies firma) needles. In relation to throughfall and stemflow, D-mannose, D-galactose, and D-glucose are the major neutral sugar components; only D-glucose is a major component of rainfall. The correlation coefficient between the total neutral sugars and uronic acid (as D-galacturonic acid), which is a key component of the cross-linking between pectic polysaccharides, was high except for rainfall. The leached amount of calcium ion, neutral sugars, uronic acid, and boron is related to the nitrate ion concentration in throughfall. Results of a laboratory exposure experiment using artificial fog water simulating the average composition of fog water observed at Mt. Oyama (simulated acid fog: SAF) on the fir seedling needles also shows a large leaching of these components from the cell walls of fir needles. The leaching amount increased concomitantly with decreasing pH of the SAF solution. We also observed that a dimeric rhamnogalacturonan II-borate complex (dRG-II-B) that exists in the cell wall as pectic polysaccharide was converted to monomeric RG-II (mRG-II) by the leaching of calcium ion and boron. Results not only of field observations but also those of laboratory experiments indicate a large effect of acid depositions on fir needles.

Transcriptomic Analysis Identifies Candidate Genes Related to Intramuscular Fat Deposition and Fatty Acid Composition in the Breast Muscle of Squabs (Columba

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Manhong Ye

2016-07-01

Full Text Available Despite the fact that squab is consumed throughout the world because of its high nutritional value and appreciated sensory attributes, aspects related to its characterization, and in particular genetic issues, have rarely been studied. In this study, meat traits in terms of pH, water-holding capacity, intramuscular fat content, and fatty acid profile of the breast muscle of squabs from two meat pigeon breeds were determined. Breed-specific differences were detected in fat-related traits of intramuscular fat content and fatty acid composition. RNA-Sequencing was applied to compare the transcriptomes of muscle and liver tissues between squabs of two breeds to identify candidate genes associated with the differences in the capacity of fat deposition. A total of 27 differentially expressed genes assigned to pathways of lipid metabolism were identified, of which, six genes belonged to the peroxisome proliferator-activated receptor signaling pathway along with four other genes. Our results confirmed in part previous reports in livestock and provided also a number of genes which had not been related to fat deposition so far. These genes can serve as a basis for further investigations to screen markers closely associated with intramuscular fat content and fatty acid composition in squabs. The data from this study were deposited in the National Center for Biotechnology Information (NCBI’s Sequence Read Archive under the accession numbers SRX1680021 and SRX1680022. This is the first transcriptome analysis of the muscle and liver tissue in Columba using next generation sequencing technology. Data provided here are of potential value to dissect functional genes influencing fat deposition in squabs.

Role of salicylic acid in alleviating oxidative damage in rice roots (Oryza sativa) subjected to cadmium stress

International Nuclear Information System (INIS)

Guo, B.; Liang, Y.C.; Zhu, Y.G.; Zhao, F.J.

2007-01-01

Time-dependent changes in enzymatic and non-enzymatic antioxidants, and lipid peroxidation were investigated in roots of rice (Oryza sativa) grown hydroponically with Cd, with or without pretreatment of salicylic acid (SA). Exposure to 50 μM Cd significantly decreased root growth, and activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), but increased the concentrations of H 2 O 2 , malondialdehyde (MDA), ascorbic acid (AsA), glutathione (GSH) and non-protein thiols (NPT). However, pretreatment with 10 μM SA enhanced the activities of antioxidant enzymes and the concentrations of non-enzymatic antioxidants, but lowered the concentrations of H 2 O 2 and MDA in the Cd-stressed rice compared with the Cd treatment alone. Pretreatment with SA alleviated the Cd-induced inhibition of root growth. The results showed that pretreatment with SA enhanced the antioxidant defense activities in Cd-stressed rice, thus alleviating Cd-induced oxidative damage and enhancing Cd tolerance. The possible mechanism of SA-induced H 2 O 2 signaling in mediating Cd tolerance was discussed. - Pretreatment with SA enhanced the antioxidant defense activities in Cd-stressed rice, thus alleviating Cd-induced oxidative damage and enhancing Cd tolerance

Folic acid and safflower oil supplementation interacts and protects embryos from maternal diabetes-induced damage.

Science.gov (United States)

Higa, R; Kurtz, M; Mazzucco, M B; Musikant, D; White, V; Jawerbaum, A

2012-05-01

Maternal diabetes increases the risk of embryo malformations. Folic acid and safflower oil supplementations have been shown to reduce embryo malformations in experimental models of diabetes. In this study we here tested whether folic acid and safflower oil supplementations interact to prevent embryo malformations in diabetic rats, and analyzed whether they act through the regulation of matrix metalloproteinases (MMPs), their endogenous inhibitors (TIMPs), and nitric oxide (NO) and reactive oxygen species production. Diabetes was induced by streptozotocin administration prior to mating. From Day 0.5 of pregnancy, rats did or did not receive folic acid (15 mg/kg) and/or a 6% safflower oil-supplemented diet. Embryos and decidua were explanted on Day 10.5 of gestation for further analysis of embryo resorptions and malformations, MMP-2 and MMP-9 activities, TIMP-1 and TIMP-2 levels, NO production and lipid peroxidation. Maternal diabetes induced resorptions and malformations that were prevented by folic acid and safflower oil supplementation. MMP-2 and MMP-9 activities were increased in embryos and decidua from diabetic rats and decreased with safflower oil and folic acid supplementations. In diabetic animals, the embryonic and decidual TIMPs were increased mainly with safflower oil supplementation in decidua and with folic acid in embryos. NO overproduction was decreased in decidua from diabetic rats treated with folic acid alone and in combination with safflower oil. These treatments also prevented increases in embryonic and decidual lipid peroxidation. In conclusion, folic acid and safflower oil supplementations interact and protect the embryos from diabetes-induced damage through several pathways related to a decrease in pro-inflammatory mediators.

Zurampic Protects Pancreatic β-Cells from High Uric Acid Induced-Damage by Inhibiting URAT1 and Inactivating the ROS/AMPK/ERK Pathways

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Ying Xin

2018-05-01

Full Text Available Background/Aims: Zurampic is a US FDA approved drug for treatment of gout. However, the influence of Zurampic on pancreatic β-cells remains unclear. The study aimed to evaluate the effects of Zurampic on high uric acid-induced damage of pancreatic β-cells and the possible underlying mechanisms. Methods: INS-1 cells and primary rat islets were stimulated with Zurampic and the mRNA expression of urate transporter 1 (URAT1 was assessed by qRT-PCR. Cells were stimulated with uric acid or uric acid plus Zurampic, and cell viability, apoptosis and ROS release were measured by MTT and flow cytometry assays. Western blot analysis was performed to evaluate the expressions of active Caspase-3 and phosphorylation of AMPK and ERK. Finally, cells were stimulated with uric acid or uric acid plus Zurampic at low/high level of glucose (2.8/16.7 mM glucose, and the insulin release was assessed by ELISA. Results: mRNA expression of URAT1 was decreased by Zurampic in a dose-dependent manner. Uric acid decreased cell viability, promoted cell apoptosis and induced ROS release. Uric acid-induced alterations could be reversed by Zurampic. Activation of Caspase-3 and phosphorylation of AMPK and ERK were enhanced by uric acid, and the enhancements were reversed by Zurampic. Decreased phosphorylation of AMPK and ERK, induced by Zurampic, was further reduced by adding inhibitor of AMPK or ERK. Besides, uric acid inhibited high glucose-induced insulin secretion and the inhibition was rescued by Zurampic. Conclusions: Zurampic has a protective effect on pancreatic β-cells against uric acid induced-damage by inhibiting URAT1 and inactivating the ROS/AMPK/ERK pathway.

Biologically relevant oxidants and terminology, classification and nomenclature of oxidatively generated damage to nucleobases and 2-deoxyribose in nucleic acids

DEFF Research Database (Denmark)

Cadet, Jean; Loft, Steffen; Olinski, Ryszard

2012-01-01

A broad scientific community is involved in investigations aimed at delineating the mechanisms of formation and cellular processing of oxidatively generated damage to nucleic acids. Perhaps as a consequence of this breadth of research expertise, there are nomenclature problems for several of the ...

Deposition of lignin droplets produced during dilute acid pretreatment of maize stems retards enzymatic hydrolysis of cellulose.

Science.gov (United States)

Selig, Michael J; Viamajala, Sridhar; Decker, Stephen R; Tucker, Melvin P; Himmel, Michael E; Vinzant, Todd 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 130 degrees C, and that they can deposit back onto the surface of residual biomass. The deposition of droplets produced under certain pretreatment conditions (acidic pH; T > 150 degrees C) 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.

Protective effects of folic acid on DNA damage and DNA methylation levels induced by N-methyl- N'-nitro- N-nitrosoguanidine in Kazakh esophageal epithelial cells.

Science.gov (United States)

Chen, Y; Feng, H; Chen, D; Abuduwaili, K; Li, X; Zhang, H

2018-01-01

The protective effects of folic acid on DNA damage and DNA methylation induced by N-methyl- N'-nitro- N-nitrosoguanidine (MNNG) in Kazakh esophageal epithelial cells were investigated using a 3 × 3 factorial design trial. The cells were cultured in vitro and exposed to media containing different concentrations of folic acid and MNNG, after which growth indices were detected. DNA damage levels were measured using comet assays, and genome-wide DNA methylation levels (MLs) were measured using high-performance liquid chromatography. The DNA methylation of methylenetetrahydrofolate reductase (MTHFR) and folate receptor- α (FR α) genes was detected by bisulfite sequencing polymerase chain reaction (PCR). The results showed significant increases in tail DNA concentration, tail length, and Olive tail moment ( p methylation frequencies of MTHFR and FR α genes. In particular, significant differences were observed in the promoter regions of both genes ( p methylation in Kazakh esophageal epithelial cells upon MNNG exposure. Thus, sufficient folic acid levels could play a protective role against the damage induced by this compound.

2.4. The kinetics of hydrochloric-acid decomposition of calcined concentrate of boron raw material of Ak-Arkhar Deposit

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Kurbonov, A.S.; Mamatov, E.D.

2015-01-01

Present article is devoted to kinetics of hydrochloric-acid decomposition of calcined concentrate of boron raw material of Ak-Arkhar Deposit. The experimental data of dependence of hydrochloric-acid decomposition of calcined boron raw material for boron oxide extraction on temperature (20-80 deg C) and process duration (15-60 min) were considered. It was defined that at temperature increasing the boron oxide extraction from borosilicate raw material increases from 24.1 till 86.8%. The constants of decomposition rate of boron raw material were calculated.

The response of gene expression associated with lipid metabolism, fat deposition and fatty acid profile in the longissimus dorsi muscle of Gannan yaks to different energy levels of diets.

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Chao Yang

Full Text Available The energy available from the diet, which affects fat deposition in vivo, is a major factor in the expression of genes regulating fat deposition in the longissimus dorsi muscle. Providing high-energy diets to yaks might increase intramuscular fat deposition and fatty acid concentrations under a traditional grazing system in cold seasons. A total of fifteen adult castrated male yaks with an initial body weight 274.3 ± 3.14 kg were analyzed for intramuscular adipose deposition and fatty acid composition. The animals were divided into three groups and fed low-energy (LE: 5.5 MJ/kg, medium-energy (ME: 6.2 MJ/kg and high-energy (HE: 6.9 MJ/kg diets, respectively. All animals were fed ad libitum twice daily at 08:00-09:00 am and 17:00-18:00 pm and with free access to water for 74 days, including a 14-d period to adapt to the diets and the environment. Intramuscular fat (IMF content, fatty acid profile and mRNA levels of genes involved in fatty acid synthesis were determined. The energy levels of the diets significantly (P<0.05 affected the content of IMF, total SFA, total MUFA and total PUFA. C16:0, C18:0 and C18:1n9c account for a large proportion of total fatty acids. Relative expression of acetyl-CoA carboxylase (ACACA, fatty acid synthase (FASN, stearoyl-CoA desaturase (SCD, sterol regulatory element-binding protein-1c (SREBP-1c, peroxisome proliferator-activated receptor γ (PPARγ and fatty acid-binding protein 4 (FABP4 was greater in HE than in LE yaks (P<0.05. Moreover, ME yaks had higher (P<0.05 mRNA expression levels of PPARγ, ACACA, FASN, SCD and FABP4 than did the LE yaks. The results demonstrate that the higher energy level of the diets increased IMF deposition and fatty acid content as well as increased intramuscular lipogenic gene expression during the experimental period.

Modeling of damage generation mechanisms in silicon at energies below the displacement threshold

International Nuclear Information System (INIS)

Santos, Ivan; Marques, Luis A.; Pelaz, Lourdes

2006-01-01

We have used molecular dynamics simulation techniques to study the generation of damage in Si within the low-energy deposition regime. We have demonstrated that energy transfers below the displacement threshold can produce a significant amount of damage, usually neglected in traditional radiation damage calculations. The formation of amorphous pockets agrees with the thermal spike concept of local melting. However, we have found that the order-disorder transition is not instantaneous, but it requires some time to reach the appropriate kinetic-potential energy redistribution for melting. The competition between the rate of this energy redistribution and the energy diffusion to the surrounding atoms determines the amount of damage generated by a given deposited energy. Our findings explain the diverse damage morphology produced by ions of different masses

Pristanic acid provokes lipid, protein, and DNA oxidative damage and reduces the antioxidant defenses in cerebellum of young rats.

Science.gov (United States)

Busanello, Estela Natacha Brandt; Lobato, Vannessa Gonçalves Araujo; Zanatta, Ângela; Borges, Clarissa Günther; Tonin, Anelise Miotti; Viegas, Carolina Maso; Manfredini, Vanusa; Ribeiro, César Augusto João; Vargas, Carmen Regla; de Souza, Diogo Onofre Gomes; Wajner, Moacir

2014-12-01

Zellweger syndrome (ZS) and some peroxisomal diseases are severe inherited disorders mainly characterized by neurological symptoms and cerebellum abnormalities, whose pathogenesis is poorly understood. Biochemically, these diseases are mainly characterized by accumulation of pristanic acid (Prist) and other fatty acids in the brain and other tissues. In this work, we evaluated the in vitro influence of Prist on redox homeostasis by measuring lipid, protein, and DNA damage, as well as the antioxidant defenses and the activities of aconitase and α-ketoglutarate dehydrogenase in cerebellum of 30-day-old rats. The effect of Prist on DNA damage was also evaluated in blood of these animals. Some parameters were also evaluated in cerebellum from neonatal rats and in cerebellum neuronal cultures. Prist significantly increased malondialdehyde (MDA) levels and carbonyl formation and reduced sulfhydryl content and glutathione (GSH) concentrations in cerebellum of young rats. It also caused DNA strand damage in cerebellum and induced a high micronuclei frequency in blood. On the other hand, this fatty acid significantly reduced α-ketoglutarate dehydrogenase and aconitase activities in rat cerebellum. We also verified that Prist-induced increase of MDA levels was totally prevented by melatonin and attenuated by α-tocopherol but not by the nitric oxide synthase inhibitor N(ω)-nitro-L-arginine methyl ester, indicating the involvement of reactive oxygen species in this effect. Cerebellum from neonate rats also showed marked alterations of redox homeostasis, including an increase of MDA levels and a decrease of sulfhydryl content and GSH concentrations elicited by Prist. Finally, Prist provoked an increase of dichlorofluorescein (DCFH) oxidation in cerebellum-cultivated neurons. Our present data indicate that Prist compromises redox homeostasis in rat cerebellum and blood and inhibits critical enzymes of the citric acid cycle that are susceptible to free radical attack. The

Ion assistance effects on electron beam deposited MgF sub 2 films

CERN Document Server

Alvisi, M; Della Patria, A; Di Giulio, M; Masetti, E; Perrone, M R; Protopapa, M L; Tepore, A

2002-01-01

Thin films of MgF sub 2 have been deposited by the ion-assisted electron-beam evaporation technique in order to find out the ion beam parameters leading to films of high laser damage threshold whose optical properties are stable under uncontrolled atmosphere conditions. It has been found that the ion-assisted electron-beam evaporation technique allows getting films with optical properties (refraction index and extinction coefficient) of high environmental stability by properly choosing the ion-source voltage and current. But, the laser damage fluence at 308 nm was quite dependent on the assisting ion beam parameters. Larger laser damage fluences have been found for the films deposited by using assisting ion beams delivered at lower anode voltage and current values. It has also been found that the films deposited without ion assistance were characterized by the highest laser damage fluence (5.9 J/cm sup 2) and the lowest environmental stability. The scanning electron microscopy analysis of the irradiated areas...

Electrodeposition of ruthenium, rhodium and palladium from nitric acid and ionic liquid media: Recovery and surface morphology of the deposits

Energy Technology Data Exchange (ETDEWEB)

Jayakumar, M.; Venkatesan, K.A.; Sudha, R. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India); Srinivasan, T.G., E-mail: tgs@igcar.gov.com [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India); Vasudeva Rao, P.R. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India)

2011-07-15

Research highlights: {yields} Platinum group metals are man-made noble metals. {yields} Electrochemical recovery of fission platinoids. {yields} Recovery from nitric acid medium. {yields} Recovery from ionic liquid medium. {yields} Platinoids with exotic surface morphologies. - Abstract: Electrodeposition is a promising technique for the recovery of platinum group metals with unique surface morphologies. The electrodeposition of palladium, ruthenium and rhodium from aqueous nitric acid, and non-aqueous 1-butyl-3-methylimidazolium chloride ionic liquid medium was studied at stainless steel electrode. The surface morphology and elemental composition of the resultant deposit were probed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analysis. Deposits with diverse surface morphologies and metal compositions were obtained by varying the composition of the electrolytic medium and applied potential. The results demonstrate the possibility of tailoring the morphologies of PGMs by controlling the composition and potential needed for electrodeposition.

Effects of the ion-solid interaction in glow discharge vapour deposition polymerization of pyromellitic dianhydride

International Nuclear Information System (INIS)

Maggioni, G.; Carturan, S.; Rigato, V.; Pieri, U.

2000-01-01

Low energy He ion bombardment of pyromellitic dianhydride monomer used in glow discharge vapour deposition polymerization (GDVDP) of polyimide coatings and its effects on the film deposition process have been studied. The sublimation of the monomer molecules and the simultaneous formation of a damaged, carbon-rich surface layer on the target are discussed from a theoretical point of view based on simulations of the ion-solid interaction. Optical emission and mass spectrometry have been used to analyse the species emitted from the target. In order to study the time evolution of the PMDA target damage, the deposition rate of monomer molecules has been monitored. FT-IR spectroscopy has been used to determine the molecular damaging of the target monomer and deposited films

Acid Rain

Science.gov (United States)

Bricker, Owen P.; Rice, Karen C.

1995-01-01

Although acid rain is fading as a political issue in the United States and funds for research in this area have largely disappeared, the acidity of rain in the Eastern United States has not changed significantly over the last decade, and it continues to be a serious environmental problem. Acid deposition (commonly called acid rain) is a term applied to all forms of atmospheric deposition of acidic substances - rain, snow, fog, acidic dry particulates, aerosols, and acid-forming gases. Water in the atmosphere reacts with certain atmospheric gases to become acidic. For example, water reacts with carbon dioxide in the atmosphere to produce a solution with a pH of about 5.6. Gases that produce acids in the presence of water in the atmosphere include carbon dioxide (which converts to carbonic acid), oxides of sulfur and nitrogen (which convert to sulfuric and nitric acids}, and hydrogen chloride (which converts to hydrochloric acid). These acid-producing gases are released to the atmosphere through natural processes, such as volcanic emissions, lightning, forest fires, and decay of organic matter. Accordingly, precipitation is slightly acidic, with a pH of 5.0 to 5.7 even in undeveloped areas. In industrialized areas, most of the acid-producing gases are released to the atmosphere from burning fossil fuels. Major emitters of acid-producing gases include power plants, industrial operations, and motor vehicles. Acid-producing gases can be transported through the atmosphere for hundreds of miles before being converted to acids and deposited as acid rain. Because acids tend to build up in the atmosphere between storms, the most acidic rain falls at the beginning of a storm, and as the rain continues, the acids "wash out" of the atmosphere.

Factors affecting the long-term response of surface waters to acidic deposition: state-of-the-science

Energy Technology Data Exchange (ETDEWEB)

Turner, R.S.; Johnson, D.W.; Elwood, J.N.; Van Winkle, W.; Clapp, R.B.; Jones, M.L.; Marmarek, D.R.; Thornton, K.W.; Gherinig, S.A.; Schnoor, J.L.

1986-01-01

Recent intensive study of the causes of surface water acidification has led to numerous hypothesized controlling mechanisms. Among these are the salt-effect reduction of alkalinity, the base cation buffering and sulfate adsorption capacities of soils, availability of weatherable minerals (weathering rates), depth of till, micropore flow, and type of forest cover. Correlative and predictive models have been developed to show the relationships (if any) between hypothesized controlling mechanisms and surface water acidity, and to suggest under what conditions additional surface water might become acid. This document (Part A) is a review of our current knowledge of factors and processes controlling soil and surface water acidification, as well as an assessment of the adequacy of that knowledge for making predictions of future acidification. Section 2 is a data extensive, conceptual overview of how watersheds function. Section 3 is a closer look at the theory and evidence for the key hypotheses. Section 4 is a review of existing methods of assessing system response to acidic deposition.

Concentrations, Deposition, and Effects of Nitrogenous Pollutants in Selected California Ecosystems

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Andrzej Bytnerowicz

2001-01-01

Full Text Available Atmospheric deposition of nitrogen (N in California ecosystems is ecologically significant and highly variable, ranging from about 1 to 45 kg/ha/year. The lowest ambient concentrations and deposition values are found in the eastern and northern parts of the Sierra Nevada Mountains and the highest in parts of the San Bernardino and San Gabriel Mountains that are most exposed to the Los Angeles air pollution plume. In the Sierra Nevada Mountains, N is deposited mostly in precipitation, although dry deposition may also provide substantial amounts of N. On the western slopes of the Sierra Nevada, the majority of airborne N is in reduced forms as ammonia (NH3 and particulate ammonium (NH4+ from agricultural activities in the California Central Valley. In southern California, most of the N air pollution is in oxidized forms as nitrogen oxides (NOx, nitric acid (HNO3, and particulate nitrate (NO3– resulting from fossil fuel combustion and subsequent complex photochemical reactions. In southern California, dry deposition of gases and particles provides most (up to 95% of the atmospheric N to forests and other ecosystems. In the mixed-conifer forest zone, elevated deposition of N may initially benefit growth of vegetation, but chronic effects may be expressed as deterioration of forest health and sustainability. HNO3 vapor alone has a potential for toxic effects causing damage of foliar surfaces of pines and oaks. In addition, dry deposition of predominantly HNO3 has lead to changes in vegetation composition and contamination of ground- and stream water where terrestrial N loading is high. Long-term, complex interactions between N deposition and other environmental stresses such as elevated ozone (O3, drought, insect infestations, fire suppression, or intensive land management practices may affect water quality and sustainability of California forests and other ecosystems.

Deposition of Coating to Protect Waste Water Reservoir in Acidic Solution by Arc Thermal Spray Process

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Han-Seung Lee

2018-01-01

Full Text Available The corrosion characteristics of 304 stainless steel (SS and titanium (Ti coatings deposited by the arc thermal spray process in pH 4 solution were assessed. The Ti-sprayed coating exhibits uniform, less porous, and adherent coating morphology compared to the SS-sprayed coating. The electrochemical study, that is, electrochemical impedance spectroscopy (EIS, revealed that as exposure periods to solution were increased, the polarization resistance (Rp decreased and the charge transfer resistance (Rct increased owing to corrosion of the metallic surface and simultaneously at the same time the deposition of oxide films/corrosion on the SS-sprayed surface, while Ti coating transformed unstable oxides into the stable phase. Potentiodynamic studies confirmed that both sprayed coatings exhibited passive tendency attributed due to the deposition of corrosion products on SS samples, whereas the Ti-sprayed sample formed passive oxide films. The Ti coating reduced the corrosion rate by more than six times compared to the SS coating after 312 h of exposure to sulfuric acid- (H2SO4- contaminated water solution, that is, pH 4. Scanning electron microscope (SEM results confirmed the uniform and globular morphology of the passive film on the Ti coating resulting in reduced corrosion. On the other hand, the corrosion products formed on SS-sprayed coating exhibit micropores with a net-like microstructure. X-ray diffraction (XRD revealed the presence of the composite oxide film on Ti-sprayed samples and lepidocrocite (γ-FeOOH on the SS-coated surface. The transformation of TiO and Ti3O into TiO2 (rutile and anatase and Ti3O5 after 312 h of exposure to H2SO4 acid reveals the improved corrosion resistance properties of Ti-sprayed coating.

Effect of PW12–GPK on the acid characteristics of Ni-, Pd- and Pt- catalysts deposited onto pillared Al montmorillonite

Directory of Open Access Journals (Sweden)

D. Zhumadullaev

2012-03-01

Full Text Available Acid characteristics of Ni-, Pd-, Pt- catalyzers , deposited to Al pillared CaH montmorillonite modified by heteropolyacid H3PW12O40·xH2O (PW12 by ammonia thermoadsorbtion method has been studied.

Radiation damage to nucleoprotein complexes in macromolecular crystallography

International Nuclear Information System (INIS)

Bury, Charles; Garman, Elspeth F.; Ginn, Helen Mary; Ravelli, Raimond B. G.; Carmichael, Ian; Kneale, Geoff; McGeehan, John E.

2015-01-01

Quantitative X-ray induced radiation damage studies employing a model protein–DNA complex revealed a striking partition of damage sites. The DNA component was observed to be far more resistant to specific damage compared with the protein. Significant progress has been made in macromolecular crystallography over recent years in both the understanding and mitigation of X-ray induced radiation damage when collecting diffraction data from crystalline proteins. In contrast, despite the large field that is productively engaged in the study of radiation chemistry of nucleic acids, particularly of DNA, there are currently very few X-ray crystallographic studies on radiation damage mechanisms in nucleic acids. Quantitative comparison of damage to protein and DNA crystals separately is challenging, but many of the issues are circumvented by studying pre-formed biological nucleoprotein complexes where direct comparison of each component can be made under the same controlled conditions. Here a model protein–DNA complex C.Esp1396I is employed to investigate specific damage mechanisms for protein and DNA in a biologically relevant complex over a large dose range (2.07–44.63 MGy). In order to allow a quantitative analysis of radiation damage sites from a complex series of macromolecular diffraction data, a computational method has been developed that is generally applicable to the field. Typical specific damage was observed for both the protein on particular amino acids and for the DNA on, for example, the cleavage of base-sugar N 1 —C and sugar-phosphate C—O bonds. Strikingly the DNA component was determined to be far more resistant to specific damage than the protein for the investigated dose range. At low doses the protein was observed to be susceptible to radiation damage while the DNA was far more resistant, damage only being observed at significantly higher doses

The smog-fog-smog cycle and acid deposition

Science.gov (United States)

Pandis, Spyros N.; Seinfeld, John H.; Pilinis, Christodoulos

1990-10-01

A model including descriptions of aerosol and droplet microphysics, gas and aqueous-phase chemistry, and deposition is used to study the transformation of aerosol to fog droplets and back to aerosol in an urban environment. Fogs in polluted environments have the potential to increase aerosol sulfate concentrations but at the same time to cause reductions in the aerosol concentration of nitrate, chloride, ammonium and sodium and well as in the total aerosol mass concentration. The sulfate produced during fog episodes favors the aerosol particles that have access to most of the fog liquid water which are usually the large particles. Aerosol scavenging efficiencies of around 80 percent are calculated for urban fogs. Sampling and subsequent mixing of fog droplets of different sizes may result in measured concentrations that are not fully representative of the fogwater chemical composition and can introduce errors in the reported values of the ionic species deposition velocities. Differences in the major ionic species deposition velocities can be explained by their distribution over the droplet size spectrum and can be correlated with the species average diameter. Two different expressions are derived for use in fog models for the calculation of the liquid water deposition velocity during fog growth and dissipation stages.

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

Directory of Open Access Journals (Sweden)

Teresa G. Valencak

2016-01-01

Full Text Available 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.

Rubber acid damage in fire hoses

Energy Technology Data Exchange (ETDEWEB)

Thaysen, A C; Bunker, H J; Adams, M E

1945-03-17

Hose failure observed in rubber-lined fire hoses may be due to sulfuric acid formed from sulfur present in hoses when they are not properly dried. Microorganisms were observed in numerous samples of hose liquid and as a result of the experiments which were carried it was concluded that: the production of rubber acid in hose is due to the activity of sulfur-oxidizing bacteria of the Thiobacterium thiooxidans group. Such acid will invariably be formed when the hoses are stored with the linings wet, when the responsible bacteria are present and when the free sulfur content of the hoses exceeds 0.1 precent. The alternative of preventing the introduction of the causal bacteria does not appear practical since the water used in fire-fighting in the London district is taken from static supplies.

Thin film femtosecond laser damage competition

Science.gov (United States)

Stolz, Christopher J.; Ristau, Detlev; Turowski, Marcus; Blaschke, Holger

2009-10-01

In order to determine the current status of thin film laser resistance within the private, academic, and government sectors, a damage competition was started at the 2008 Boulder Damage Symposium. This damage competition allows a direct comparison of the current state of the art of high laser resistance coatings since they are tested using the same damage test setup and the same protocol. In 2009 a high reflector coating was selected at a wavelength of 786 nm at normal incidence at a pulse length of 180 femtoseconds. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials and layer count, and spectral results will also be shared.

Mitigation of Debris Flow Damage--­ A Case Study of Debris Flow Damage

Science.gov (United States)

Lin, J. C.; Jen, C. H.

Typhoon Toraji caused more than 30 casualties in Central Taiwan on the 31st July 2001. It was the biggest Typhoon since the Chi-Chi earthquake of 1999 with huge amounts of rainfall. Because of the influence of the earthquake, loose debris falls and flows became major hazards in Central Taiwan. Analysis of rainfall data and sites of slope failure show that damage from these natural hazards were enhanced as a result of the Chi-Chi earthquake. Three main types of hazard occurred in Central Taiwan: land- slides, debris flows and gully erosion. Landslides occurred mainly along hill slopes and banks of channels. Many dams and houses were destroyed by flooding. Debris flows occurred during typhoon periods and re-activated ancient debris depositions. Many new gullies were therefore developed from deposits loosened and shaken by the earthquake. This paper demonstrates the geological/geomorphological background of the hazard area, and reviews methods of damage mitigation in central Taiwan. A good example is Hsi-Tou, which had experienced no gully erosion for more than 40 years. The area experienced much gully erosion as a result of the combined effects of earth- quake and typhoon. Although Typhoon Toraji produced only 30% of the rainfall of Typhoon Herb of 1996, it caused more damage in the Hsi-Tou area. The mitigation of debris flow hazards in Hsi-tou area is discussed in this paper.

Effect of heat treatment on the characteristics of tool steel deposited by the directed energy deposition process

Science.gov (United States)

Park, Jun Seok; Lee, Min-Gyu; Cho, Yong-Jae; Sung, Ji Hyun; Jeong, Myeong-Sik; Lee, Sang-Kon; Choi, Yong-Jin; Kim, Da Hye

2016-01-01

The directed energy deposition process has been mainly applied to re-work and the restoration of damaged steel. Differences in material properties between the base and the newly deposited materials are unavoidable, which may affect the mechanical properties and durability of the part. We investigated the effect of heat treatment on the characteristics of tool steel deposited by the DED process. We prepared general tool steel materials of H13 and D2 that were deposited onto heat-treated substrates of H13 and D2, respectively, using a direct metal tooling process. The hardness and microstructure of the deposited steel before and after heat treatment were investigated. The hardness of the deposited H13 steel was higher than that of wrought H13 steel substrate, while that of the deposited D2 was lower than that of wrought D2. The evolution of the microstructures by deposition and heat treatment varied depending on the materials. In particular, the microstructure of the deposited D2 steel after heat treatment consisted of fine carbides in tempered martensite and it is expected that the deposited D2 steel will have isotropic properties and high hardness after heat treatment.

Whole-lake algal responses to a century of acidic industrial deposition on the Canadian Shield

International Nuclear Information System (INIS)

Vinebrooke, R.D.; Dixit, S.S.; Graham, M.D.; Gunn, J.M.; Chen, Y.-W.; Belzile, N.

2002-01-01

A century of cultural acidification is hypothesized to have altered algal community structure in boreal lakes. To date, this hypothesis has remained untested because of both the lack of data predating the onset of industrial pollution and incomplete estimates of whole-lake algal community structure. High-pressure liquid chromatography (HPLC) of sedimentary pigments was used to quantify whole-lake algal responses to acid deposition in six boreal lakes located in Killarney Park, Ontario, Canada. Concomitant significant increases in chlorophyll and carotenoid concentrations, diatom-inferred lake acidity, and metal levels since 1900 suggested that algal abundances in four acidified lakes and one small, circumneutral lake were enhanced by aerial pollution. An alternate explanation is that increased acidity and underwater light availability in the acidified lakes shifted algal abundance towards phytobenthos and deepwater phytoplankton, whose pigment signatures were better preserved in the sediments. Taxonomically diagnostic pigment stratigraphies were consistent with shifts in algal community structure towards filamentous green phytobenthos and deepwater phytoflagellates in the acidified lakes. Our findings suggest that decades of aerial pollution have altered the base of foodwebs in boreal lakes, potentially rendering them less resilient to other environmental stressors. (author)

Plasma membrane damage detected by nucleic acid leakage

International Nuclear Information System (INIS)

Fortunati, E.; Bianchi, V.

1989-01-01

Among the indicators of membrane damage, the leakage of intracellular components into the medium is the most directly related to the perturbations of the membrane molecular organization. The extent of the damage can be evaluated from the size of the released components. We have designed a protocol for the detection of membrane leakage based on the preincubation of cells with tritiated adenine for 24 h, followed by a 24-h chase in nonradioactive medium. The treatment takes place when the distribution of the precursor among its end products has reached the plateau, and thus the differences of radioactivity in the fractions obtained from the control and treated cultures (medium, nucleotide pool, RNA, DNA) correspond to actual quantitative variations induced by the test chemical. Aliquots of the medium are processed to determine which percentage of the released material is macromolecular, in order to distinguish between mild and severe membrane damage. The origin of the extracellular radioactivity can be recognized from the variations of RNA counts in the treated cells. DNA radioactivity is used to evaluate the number of cells that remain attached to the plates in the different conditions of treatment. By this means, generalized permeabilization of membranes to macromolecules is distinguished from complete solubilization of only a subpopulation of cells. We present some examples of application of the protocol with detergents (LAS, SDS, Triton X-100) and with Cr(VI), which damages cell membranes by a different mechanism of action

Comparison of the Al back contact deposited by sputtering, e-beam, or thermal evaporation for inverted perovskite solar cells

Science.gov (United States)

Wahl, Tina; Hanisch, Jonas; Ahlswede, Erik

2018-04-01

In this work, we present inverted perovskite solar cells with Al top electrodes, which were deposited by three different methods. Besides the widely used thermal evaporation of Al, we also used the industrially important high deposition rate processes sputtering and electron beam evaporation for aluminium electrodes and examined the influence of the deposition method on the solar cell performance. The current-voltage characteristics of as grown solar cells with sputtered and e-beam Al electrode show an s-shape due to damage done to the organic electronic transport layers (ETL) during Al deposition. It can be cured by a short annealing step at a moderate temperature so that fill factors  >60% and power conversion efficiencies of almost 12% with negligible hysteresis can be achieved. While solar cells with thermally evaporated Al electrode do not show an s-shape, they also exhibit a clear improvement after a short annealing step. In addition, we varied the thickness of the ETL consisting of a double layer ([6,6]-Phenyl-C61-butyric acid methyl ester and bathocuproine) and investigated the influence on the solar cell parameters for the three different Al deposition methods, which showed distinct dependencies on ETL thickness.

Ion-assisted deposition of thin films

International Nuclear Information System (INIS)

Barnett, S.A.; Choi, C.H.; Kaspi, R.; Millunchick, J.M.

1993-01-01

Recent work on low-energy ion-assisted deposition of epitaxial films is reviewed. Much of the recent interest in this area has been centered on the use of very low ion energies (∼ 25 eV) and high fluxes (> 1 ion per deposited atom) obtained using novel ion-assisted deposition techniques. These methods have been applied in ultra-high vacuum, allowing the preparation of high-purity device-quality semiconductor materials. The following ion-surface interaction effects during epitaxy are discussed: improvements in crystalline perfection during low temperature epitaxy, ion damage, improved homogeneity and properties in III-V alloys grown within miscibility gaps, and changes in nucleation mechanism during heteroepitaxial growth

Antiretroviral therapy-induced insulin resistance and oxidative deoxy nucleic acid damage in human immunodeficiency virus-1 patients

Directory of Open Access Journals (Sweden)

Vaishali Kolgiri Honnapurmath

2017-01-01

Full Text Available Background and Objectives: Insulin resistance (IR is frequent in human immunodeficiency virus (HIV infection and may be related to antiretroviral therapy (ART. Increased oxidative stress parameters and carbonyl protein are linked to insulin sensitivity. The present study is aimed to determine IR, its association with oxidative deoxy nucleic acid (DNA damage in HIV-1-infected patients with different ART status. Materials and Methods: In this case–control study, a total 600 subjects were included. We used plasma levels of the oxidized base, 8-hydroxy-2-deoxyguanosine (8-OHdG, as our biomarker of oxidative DNA damage. 8-OHdG was measured with the highly sensitive 8-OHdG check enzyme-linked immunosorbent assay kit. IR was determined using homeostasis model assessment. Results: All subjects were randomly selected and grouped as HIV-negative (control group (n = 300, HIV-positive without ART (n = 100, HIV-positive with ART first line (n = 100, and HIV-positive with ART second line (n = 100. IR and oxidative DNA damage were significantly higher in HIV-positive patients with second-line ART and HIV-positive patients with first-line ART than ART-naive patients. In a linear regression analysis, increased IR was positively associated with the increased DNA damage (odds ratio: 3.052, 95% confidence interval: 2.595–3.509 P < 0.001. Interpretation and Conclusions: In this study, we observed that ART plays a significant role in the development of IR and oxidative DNA damage in HIV-positive patients taking ART. Awareness and knowledge of these biomarkers may prove helpful to clinicians while prescribing ART to HIV/AIDS patients. Larger studies are warranted to determine the exact role of ART in the induction of IR and DNA damage.

Pharmacology of post-irradiation damage of blood capillaries

International Nuclear Information System (INIS)

Pospisil, J.; Pouckova, P.

1979-01-01

Available literature data are summed up on the effect of a number of substances on irradiation damage to blood capillaries. The substances include vitamins, bioflavonoids, serotonine, histamine, bradykinin, ACTH, adrenal hormones, vasopressin, estrogens, prostaglandins, escin 1-butanol, diisopropylfluorophosphate, phenoxybenzamine, 1,4-dihydroxybenzenesulphonic acid derivatives, and xi-aminohexanoic acid. The data include the effects of the substances administered before and after irradiation on blood capillary damage and on mortality. (Ha)

Atmospheric concentrations and deposition of oxidised sulfur and nitrogen species at Petaling Jaya, Malaysia, 1993-1998

Energy Technology Data Exchange (ETDEWEB)

Ayers, G.P.; Gillett, R.W.; Manins, P.C. [CSIRO Atmospheric Research, Aspendale, VIC (Australia); Peng Leong Chow; Fook Lim Sze [Malaysian Meteorological Service, Petaling Jaya (Malaysia); Kong Cheah Wai [Tenaga Nasional R and D Berhad, Kajang (Malaysia)

2000-02-01

Wet-only rainwater composition, acid-precursor gas mixing ratios and aerosol loading were determined from weekly-averaged samples at Petaling Jaya, Malaysia, over the five year period from March 1993 to March 1998. Annual deposition fluxes of acidic sulfur and nitrogen species estimated from these data show this site to be heavily impacted by acidic deposition, with total oxidised sulfur plus nitrogen deposition in the range 277-480 meq m{sup -2} yr{sup -1}. Average contributions were 56% as sulfur species, 44% as nitrogen species, with wet deposition in this region of high rainfall accounting for 67% of total deposition. Thus total acid deposition fluxes were equivalent to levels that provided motivation for emissions reduction programs in both Europe and North America. The possibility of adverse environmental effects in Malaysia caused by acid deposition therefore merits serious consideration and assessment.

Uptake of raft components into amyloid β-peptide aggregates and membrane damage.

Science.gov (United States)

Sasahara, Kenji; Morigaki, Kenichi; Mori, Yasuko

2015-07-15

Amyloid aggregation and deposition of amyloid β-peptide (Aβ) are pathologic characteristics of Alzheimer's disease (AD). Recent reports have shown that the association of Aβ with membranes containing ganglioside GM1 (GM1) plays a pivotal role in amyloid deposition and the pathogenesis of AD. However, the molecular interactions responsible for membrane damage associated with Aβ deposition are not fully understood. In this study, we microscopically observed amyloid aggregation of Aβ in the presence of lipid vesicles and on a substrate-supported planar membrane containing raft components and GM1. The experimental system enabled us to observe lipid-associated aggregation of Aβ, uptake of the raft components into Aβ aggregates, and relevant membrane damage. The results indicate that uptake of raft components from the membrane into Aβ deposits induces macroscopic heterogeneity of the membrane structure. Copyright © 2015 Elsevier Inc. All rights reserved.

Prevention Effect of Poly-Gamma-Glutamic Acid on Tissue Damage Induced by Gamma Irradiation as a Natural Cross-Linker

Energy Technology Data Exchange (ETDEWEB)

Kim, Jaehun; Sung, Nakyun; Kim, Jeongsoo; Jo, Euri; Choi, Jongil; Park, Jongheum; Lee, Juwoon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Kwangwon [Eulji Univ. Hospital, Daejeon (Korea, Republic of); Kwon, Jungkee [Chonbuk National Univ., Jeonju (Korea, Republic of); Kim, Taewoon [Jeonbuk Technopark, Jeonju (Korea, Republic of)

2012-03-15

This study was to determine the prevention effect of poly-gamma-glutamic acid (PGA) on tissue damage induced by gamma irradiation for development of xenograft. PGA (MW 2000 kDa) extracted from permeated soy bean (natto) was used in this study as natural compound, and glutaraldehyde (GA) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) were used as a control, chemical based cross-linking agents. GA, EDC and PGA treated porcine tendons were gamma-irradiated at the dose of 30 kGy. Prevention effects against tissue damage were measured as the result of tensile strength, hydroxyproline contents and tissue morphological analysis. Tensile of porcine tendon was remarkably decreased by gamma irradiation, but increased in PGA treated group. Morphological analysis showed that collagen structure was broken by gamma irradiation, but attenuated by PGA treatment. Base on the results, it demonstrated that gamma irradiation can induce severe alteration of porcine tendon, but PGA can effectively improve the tissue damage.

Prevention Effect of Poly-Gamma-Glutamic Acid on Tissue Damage Induced by Gamma Irradiation as a Natural Cross-Linker

International Nuclear Information System (INIS)

Kim, Jaehun; Sung, Nakyun; Kim, Jeongsoo; Jo, Euri; Choi, Jongil; Park, Jongheum; Lee, Juwoon; Lee, Kwangwon; Kwon, Jungkee; Kim, Taewoon

2012-01-01

This study was to determine the prevention effect of poly-gamma-glutamic acid (PGA) on tissue damage induced by gamma irradiation for development of xenograft. PGA (MW 2000 kDa) extracted from permeated soy bean (natto) was used in this study as natural compound, and glutaraldehyde (GA) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) were used as a control, chemical based cross-linking agents. GA, EDC and PGA treated porcine tendons were gamma-irradiated at the dose of 30 kGy. Prevention effects against tissue damage were measured as the result of tensile strength, hydroxyproline contents and tissue morphological analysis. Tensile of porcine tendon was remarkably decreased by gamma irradiation, but increased in PGA treated group. Morphological analysis showed that collagen structure was broken by gamma irradiation, but attenuated by PGA treatment. Base on the results, it demonstrated that gamma irradiation can induce severe alteration of porcine tendon, but PGA can effectively improve the tissue damage

Over-expression of heme oxygenase-1 promotes oxidative mitochondrial damage in rat astroglia.

Science.gov (United States)

Song, Wei; Su, Haixiang; Song, Sisi; Paudel, Hemant K; Schipper, Hyman M

2006-03-01

Glial heme oxygenase-1 is over-expressed in the CNS of subjects with Alzheimer disease (AD), Parkinson disease (PD) and multiple sclerosis (MS). Up-regulation of HO-1 in rat astroglia has been shown to facilitate iron sequestration by the mitochondrial compartment. To determine whether HO-1 induction promotes mitochondrial oxidative stress, assays for 8-epiPGF(2alpha) (ELISA), protein carbonyls (ELISA) and 8-OHdG (HPLC-EC) were used to quantify oxidative damage to lipids, proteins, and nucleic acids, respectively, in mitochondrial fractions and whole-cell compartments derived from cultured rat astroglia engineered to over-express human (h) HO-1 by transient transfection. Cell viability was assessed by trypan blue exclusion and the MTT assay, and cell proliferation was determined by [3H] thymidine incorporation and total cell counts. In rat astrocytes, hHO-1 over-expression (x 3 days) resulted in significant oxidative damage to mitochondrial lipids, proteins, and nucleic acids, partial growth arrest, and increased cell death. These effects were attenuated by incubation with 1 microM tin mesoporphyrin, a competitive HO inhibitor, or the iron chelator, deferoxamine. Up-regulation of HO-1 engenders oxidative mitochondrial injury in cultured rat astroglia. Heme-derived ferrous iron and carbon monoxide (CO) may mediate the oxidative modification of mitochondrial lipids, proteins and nucleic acids in these cells. Glial HO-1 hyperactivity may contribute to cellular oxidative stress, pathological iron deposition, and bioenergetic failure characteristic of degenerating and inflamed neural tissues and may constitute a rational target for therapeutic intervention in these conditions. Copyright 2005 Wiley-Liss, Inc.

Effect of glycerin and formic acid in the efficiency of deposit on Zn-Ni, obtained by electrodeposition; Efeito da glicerina e do acido formico na eficiencia de deposito da liga Zn-Ni, obtido atraves de eletrodeposicao

Energy Technology Data Exchange (ETDEWEB)

Pedroza, G.A.G.; Souza, C.A.C.; Lima, L.R.P.A.; Ferreira, D.M. [Universidade Federal da Bahia - Escola Politecnica, BA (Brazil)

2010-07-01

Additives are added to the electrodeposition of metal coatings to improve the characteristics of the deposit. However, the objective was to investigate the effect of adding glycerin and formic acid in the deposition efficiency and deposit structure of zinc-nickel alloy obtained by electrodeposition. The depositions were made at a galvanostatic current density of 10 mA/cm{sup 2} to obtain a deposit of about 5 mm in thickness. The deposition efficiency was determined through measures of mass, chemical composition of the deposit in the presence and absence of additives was examined by X-ray Spectrometer Fluorescence (XRF) and surface characterization of coatings was performed by Scanning Electron Microscopy (SEM). The high levels of glycerin (0,07 M) and formic acid (0,26 M) in bath deposition increased the deposition efficiency of around 10% to 12% by mass, respectively. (author)

Relationship between cross section measurements and understanding radiation induced damage to biomolecules

International Nuclear Information System (INIS)

DuBois, R.D.; Braby, L.A.

1993-10-01

Experimental research performed at the Pacific Northwest Laboratory relating to energy deposition by energetic charged particles is described. How cross section data obtained from gaseous- and condensed-phase studies are related to understanding damage to biomolecules is discussed. Studies to date stress the need for information about energy deposition in individual interactions and show that multiple ionization may play a very significant role in biological damage. Current efforts to relate this gas-phase information to condensed-phase processes and biologically relevant targets are outlined

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

Science.gov (United States)

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

Photocatalytic activity of tin-doped TiO{sub 2} film deposited via aerosol assisted chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Chua, Chin Sheng, E-mail: cschua@simtech.a-star.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore); Tan, Ooi Kiang; Tse, Man Siu [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Ding, Xingzhao [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore)

2013-10-01

Tin-doped TiO{sub 2} films are deposited via aerosol assisted chemical vapor deposition using a precursor mixture composing of titanium tetraisopropoxide and tetrabutyl tin. The amount of tin doping in the deposited films is controlled by the volume % concentration ratio of tetrabutyl tin over titanium tetraisopropoxide in the mixed precursor solution. X-ray diffraction analysis results reveal that the as-deposited films are composed of pure anatase TiO{sub 2} phase. Red-shift in the absorbance spectra is observed attributed to the introduction of Sn{sup 4+} band states below the conduction band of TiO{sub 2}. The effect of tin doping on the photocatalytic property of TiO{sub 2} films is studied through the degradation of stearic acid under UV light illumination. It is found that there is a 10% enhancement on the degradation rate of stearic acid for the film with 3.8% tin doping in comparison with pure TiO{sub 2} film. This improvement of photocatalytic performance with tin incorporation could be ascribed to the reduction of electron-hole recombination rate through charge separation and an increased amount of OH radicals which are crucial for the degradation of stearic acid. Further increase in tin doping results in the formation of recombination site and large anatase grains, which leads to a decrease in the degradation rate. - Highlights: ► Deposition of tin-doped TiO{sub 2} film via aerosol assisted chemical vapor deposition ► Deposited anatase films show red-shifted in UV–vis spectrum with tin-dopants. ► Photoactivity improves at low tin concentration but reduces at higher concentration. ► Improvement in photoactivity due to bandgap narrowing from Sn{sup 4+} band states ► Maximum photoactivity achieved occurs for films with 3.8% tin doping.

Insights into cadmium induced physiological and ultra-structural disorders in Juncus effusus L. and its remediation through exogenous citric acid

International Nuclear Information System (INIS)

Najeeb, Ullah; Jilani, Ghulam; Ali, Shafaqat; Sarwar, Muhammad; Xu Ling; Zhou, Weijun

2011-01-01

This study appraised cadmium (Cd) toxicity stress in wetland plant Juncus effusus, and explored its potential for Cd phytoextraction through chelators (citric acid and EDTA). Cadmium altered morphological and physiological attributes of J. effusus as reflected by growth retardation. Citric acid in the presence of 100 μM Cd significantly countered Cd toxicity by improving plant growth. Elevated Cd concentrations reduced translocation factor that was increased under application of both chelators. Citric acid enhanced Cd accumulation, while EDTA reduced its uptake. Cadmium induced oxidative stress modified the antioxidative enzyme activity. Both levels of citric acid (2.5 and 5.0 mM) and lower EDTA concentration (2.5 mM) helped plants to overcome oxidative stress by enhancing their antioxidative enzyme activities. Cadmium damaged the root cells through cytoplasmic shrinkage and metal deposition. Citric acid restored structure and shape of root cells and eliminated plasmolysis; whereas, EDTA exhibited no positive effect on it. Shoot cells remained unaffected under Cd treatment alone or with citric acid except for chloroplast swelling. Only EDTA promoted starch accumulation in chloroplast reflecting its negative impact on cellular structure. It concludes that Cd and EDTA induce structural and morphological damage in J. effusus; while, citric acid ameliorates Cd toxicity stress.

Insights into cadmium induced physiological and ultra-structural disorders in Juncus effusus L. and its remediation through exogenous citric acid

Energy Technology Data Exchange (ETDEWEB)

Najeeb, Ullah [Institute of Crop Science, Zhejiang University, Hangzhou 310029 (China); Crop Sciences Institute, National Agriculture Research Centre, Islamabad 45500 (Pakistan); Jilani, Ghulam, E-mail: jilani@uaar.edu.pk [Department of Soil Science, PMAS Arid Agriculture University, Rawalpindi, Punjab 46300 (Pakistan); Ali, Shafaqat [Institute of Crop Science, Zhejiang University, Hangzhou 310029 (China); Sarwar, Muhammad [Land Resources Research Institute, National Agriculture Research Centre, Islamabad 45500 (Pakistan); Xu Ling [Institute of Crop Science, Zhejiang University, Hangzhou 310029 (China); Zhou, Weijun, E-mail: wjzhou@zju.edu.cn [Institute of Crop Science, Zhejiang University, Hangzhou 310029 (China)

2011-02-15

This study appraised cadmium (Cd) toxicity stress in wetland plant Juncus effusus, and explored its potential for Cd phytoextraction through chelators (citric acid and EDTA). Cadmium altered morphological and physiological attributes of J. effusus as reflected by growth retardation. Citric acid in the presence of 100 {mu}M Cd significantly countered Cd toxicity by improving plant growth. Elevated Cd concentrations reduced translocation factor that was increased under application of both chelators. Citric acid enhanced Cd accumulation, while EDTA reduced its uptake. Cadmium induced oxidative stress modified the antioxidative enzyme activity. Both levels of citric acid (2.5 and 5.0 mM) and lower EDTA concentration (2.5 mM) helped plants to overcome oxidative stress by enhancing their antioxidative enzyme activities. Cadmium damaged the root cells through cytoplasmic shrinkage and metal deposition. Citric acid restored structure and shape of root cells and eliminated plasmolysis; whereas, EDTA exhibited no positive effect on it. Shoot cells remained unaffected under Cd treatment alone or with citric acid except for chloroplast swelling. Only EDTA promoted starch accumulation in chloroplast reflecting its negative impact on cellular structure. It concludes that Cd and EDTA induce structural and morphological damage in J. effusus; while, citric acid ameliorates Cd toxicity stress.

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

Science.gov (United States)

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.

RBS and NRA damage analysis on PFA films bombarded with hydrogen

International Nuclear Information System (INIS)

Parada, Marco A.; Petchevist, Paulo C.D.; Minamisawa, Renato A.; Almeida, Adelaide de; Muntele, Claudiu I.; Zimmerman, Robert L.; Ila, Daryush

2005-01-01

The fluoropolymer PFA (Tetrafluoroethylene-per-fluoromethoxy ethylene) is a conventional thermoplastic used in civil engineering applications such as anti-adherent coatings and concrete additives. It is also candidate materials for radiation dosimetry with applications in medical physics. When such a polymer is exposed to ionizing radiation, it can suffers damages that depend on the type, energy, and intensity of the radiation. We present results on the damage caused by 1 MeV protons at fluences of 10 13 , 10 14 , 10 15 , and 10 16 protons/cm 2 . The energy deposited during such hydrogen bombardment breaks the polymeric chains with the release of fluorine in amounts directly proportional to the amount of deposited energy. Virgin samples were first analyzed by RBS. Subsequent damage was then profiled by monitoring the alpha emission spectrum, resulting from the nuclear reaction: 19 F(p,αγ) 16 O induced by 1.38 MeV protons on the remaining fluorine content of damaged polymer samples. (author)

New insight into silica deposition in horsetail (Equisetum arvense

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Exley Christopher

2011-07-01

Full Text Available Abstract Background The horsetails (Equisetum sp are known biosilicifiers though the mechanism underlying silica deposition in these plants remains largely unknown. Tissue extracts from horsetails grown hydroponically and also collected from the wild were acid-digested in a microwave oven and their silica 'skeletons' visualised using the fluor, PDMPO, and fluorescence microscopy. Results Silica deposits were observed in all plant regions from the rhizome through to the stem, leaf and spores. Numerous structures were silicified including cell walls, cell plates, plasmodesmata, and guard cells and stomata at varying stages of differentiation. All of the major sites of silica deposition in horsetail mimicked sites and structures where the hemicellulose, callose is known to be found and these serendipitous observations of the coincidence of silica and callose raised the possibility that callose might be templating silica deposition in horsetail. Hydroponic culture of horsetail in the absence of silicic acid resulted in normal healthy plants which, following acid digestion, showed no deposition of silica anywhere in their tissues. To test the hypothesis that callose might be templating silica deposition in horsetail commercially available callose was mixed with undersaturated and saturated solutions of silicic acid and the formation of silica was demonstrated by fluorimetry and fluorescence microscopy. Conclusions The initiation of silica formation by callose is the first example whereby any biomolecule has been shown to induce, as compared to catalyse, the formation of silica in an undersaturated solution of silicic acid. This novel discovery allowed us to speculate that callose and its associated biochemical machinery could be a missing link in our understanding of biosilicification.

Ascorbic acid (AA) metabolism in protection against radiation damage

International Nuclear Information System (INIS)

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

1986-01-01

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 14 C-AA and 1 mM thiourea (to slow spontaneous oxidation of AA). Aliquots were assayed by HPLC and scintillation spectrometry to identify the 14 C-label. Samples exposed to Cobalt-60 radiation had a half time of AA decay of 30 minutes) indicating that AA scavenges radiation-induced free radicals and forms the ascorbate free radical (AFR). Pairs of 14 C-AFR disproportionate, with the net effect of 14 C-dehydroascorbic acid formation from 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 0 C in the presence of 15 μM 14 C-AA. Samples of supernatant maintained at 100 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

Lipase biofilm deposited by Matrix Assisted Pulsed Laser Evaporation technique

International Nuclear Information System (INIS)

Aronne, Antonio; Bloisi, Francesco; Calabria, Raffaela; Califano, Valeria; Depero, Laura E.; Fanelli, Esther; Federici, Stefania; Massoli, Patrizio; Vicari, Luciano R.M.

2015-01-01

Highlights: • A lipase film was deposited with Matrix Assisted Pulsed Laser Evaporation technique. • FTIR spectra show that laser irradiation do not damage lipase molecule. • Laser fluence controls the characteristics of complex structure generated by MAPLE. - Abstract: Lipase is an enzyme that finds application in biodiesel production and for detection of esters and triglycerides in biosensors. Matrix Assisted Pulsed Laser Evaporation (MAPLE), a technique derived from Pulsed Laser Deposition (PLD) for deposition of undamaged biomolecules or polymers, is characterized by the use of a frozen target obtained from a solution/suspension of the guest material (to be deposited) in a volatile matrix (solvent). The presence of the solvent avoids or at least reduces the potential damage of guest molecules by laser radiation but only the guest material reaches the substrate in an essentially solvent-free deposition. MAPLE can be used for enzymes immobilization, essential for industrial application, allowing the development of continuous processes, an easier separation of products, the reuse of the catalyst and, in some cases, enhancing enzyme properties (pH, temperature stability, etc.) and catalytic activity in non-aqueous media. Here we show that MAPLE technique can be used to deposit undamaged lipase and that the complex structure (due to droplets generated during extraction from target) of the deposited material can be controlled by changing the laser beam fluence

Lipase biofilm deposited by Matrix Assisted Pulsed Laser Evaporation technique

Energy Technology Data Exchange (ETDEWEB)

Aronne, Antonio [Department of Chemical Engineering, Materials and Industrial Production, University of Naples “Federico II”, Napoli (Italy); Bloisi, Francesco, E-mail: bloisi@na.infn.it [SPIN – CNR, Naples (Italy); Department of Physics, University of Naples “Federico II”, Napoli (Italy); Calabria, Raffaela; Califano, Valeria [Istituto Motori – CNR, Naples (Italy); Depero, Laura E. [Department of Mechanical and Industrial Engineering, University of Brescia, Brescia (Italy); Fanelli, Esther [Department of Chemical Engineering, Materials and Industrial Production, University of Naples “Federico II”, Napoli (Italy); Federici, Stefania [Department of Mechanical and Industrial Engineering, University of Brescia, Brescia (Italy); Massoli, Patrizio [Istituto Motori – CNR, Naples (Italy); Vicari, Luciano R.M. [SPIN – CNR, Naples (Italy); Department of Physics, University of Naples “Federico II”, Napoli (Italy)

2015-05-01

Highlights: • A lipase film was deposited with Matrix Assisted Pulsed Laser Evaporation technique. • FTIR spectra show that laser irradiation do not damage lipase molecule. • Laser fluence controls the characteristics of complex structure generated by MAPLE. - Abstract: Lipase is an enzyme that finds application in biodiesel production and for detection of esters and triglycerides in biosensors. Matrix Assisted Pulsed Laser Evaporation (MAPLE), a technique derived from Pulsed Laser Deposition (PLD) for deposition of undamaged biomolecules or polymers, is characterized by the use of a frozen target obtained from a solution/suspension of the guest material (to be deposited) in a volatile matrix (solvent). The presence of the solvent avoids or at least reduces the potential damage of guest molecules by laser radiation but only the guest material reaches the substrate in an essentially solvent-free deposition. MAPLE can be used for enzymes immobilization, essential for industrial application, allowing the development of continuous processes, an easier separation of products, the reuse of the catalyst and, in some cases, enhancing enzyme properties (pH, temperature stability, etc.) and catalytic activity in non-aqueous media. Here we show that MAPLE technique can be used to deposit undamaged lipase and that the complex structure (due to droplets generated during extraction from target) of the deposited material can be controlled by changing the laser beam fluence.

Effect of Salicylic Acid on Alleviating of Electrolyte Leakage and Flower Organ Damage in Apricot (Prunus armeniaca L. cv. ‘Shahroudi’

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Morteza ALIREZAIE NOGHONDAR

2013-02-01

Full Text Available One of the most important limiting factors in spread of apricot in Iran is late spring frost, which damages flower bud and decrease total yield of crop. It has been found that salicylic acid (SA plays a beneficial role during plant response to chilling and freezing stresses. To evaluate the effects of salicylic acid on alleviating of cold stress, the flower buds (FBs of Prunus armeniaca L. cv. ‘Shahroudi’ were sprayed at pink cluster stage with SA at 4 levels (0, 0.5, 1 and 2 mM and were then exposed to artificial cold stress (4 h at -4°C or without cold stress (+ 25. Experimental attributes including electrolyte leakage of FBs and percentage of damage (PD of pistil, anthers and petals to temperature treatments were determined. The results showed that at -4°C the lowest and highest PD and EL of FBs were observed in application of 0.5 and 0 mM SA, respectively. The highest and lowest PD of flower organ and EL were obtained in application of 0 and 2 mM SA, respectively at +25°C. Based on the results of this experiment, SA alleviates the negative effect of cold stress on electrolyte leakage and flower organ damages in apricot cv. ‘Shahroudi’, depending on the concentrations of SA used.

Treatment of acid drainage in uranium deposit by means of a natural wetland

International Nuclear Information System (INIS)

Grudeva, V.I.; Stoyanova, A.D.; Grudev, S.N.

2004-01-01

Acid drainage waters generated in the uranium deposit G-1, Western Bulgaria, were treated by means of a natural wetland located in the deposit. The waters had a pH in the range of about 2.4-3.9 and contained uranium and radium radionuclides, heavy metals (copper, zinc , cadmium, iron, manganese) arsenic and sulfates in concentrations usually much higher than the relevant permissible levels for waters intended for use in agriculture and/or industry. The wetland was characterized by abundant and emergent vegetation and a diverse microflora. Typha latifolia, Typha augustifolia and Potamogeton australis were the main plant species in the wetland but representatives of the genera Scirpus, Juncus, Elepchoris, Potamogeton, Carex and Poa as well as different algae were also present. The water flows through the wetland varied in the range at about 0.2-1,2 l/s reflecting water residence times in the wetland of about 10-50 hours. An efficient water cleanup took place in the wetland even during the cold winter months at ambient temperatures close to 0 o C. The removal of pollutants was due to different processes but the microbial dissimilatory sulphate reduction and the sorption of pollutants on organic matter (living and dead plant and microbial biomass) and clays present in the wetland played the main role. (author)

Biosensor Applications of MAPLE Deposited Lipase

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Valeria Califano

2014-10-01

Full Text Available Matrix Assisted Pulsed Laser Evaporation (MAPLE is a thin film deposition technique derived from Pulsed Laser Deposition (PLD for deposition of delicate (polymers, complex biological molecules, etc. materials in undamaged form. The main difference of MAPLE technique with respect to PLD is the target: it is a frozen solution or suspension of the (guest molecules to be deposited in a volatile substance (matrix. Since laser beam energy is mainly absorbed by the matrix, damages to the delicate guest molecules are avoided, or at least reduced. Lipase, an enzyme catalyzing reactions borne by triglycerides, has been used in biosensors for detection of β-hydroxyacid esters and triglycerides in blood serum. Enzymes immobilization on a substrate is therefore required. In this paper we show that it is possible, using MAPLE technique, to deposit lipase on a substrate, as shown by AFM observation, preserving its conformational structure, as shown by FTIR analysis.

An Evaluation of the Role of Ozone, Acid Deposition, and other Airborne Pollutants in the Forests of Eastern North America

Science.gov (United States)

J.H.B. Garner; Terry Pagano; Ellis B. Cowling

1989-01-01

Existing knowledge on air pollutants that occur in the forests of eastern North America is summarized and interpreted.Resolution is sought to the conflict between the prevailing scientific judgment that ozone and other oxidants are most likely to be damaging eastern forests and the prevailing public perception that acidic and acidifying substances are the most likely...

Evaluation of physical and chemical properties and their interactions in fat, oil, and grease (FOG) deposits.

Science.gov (United States)

Gross, Martin A; Jensen, Jeanette L; Gracz, Hanna S; Dancer, Jens; Keener, Kevin M

2017-10-15

Fat, oil and grease (FOG) blockages in sewer systems are a substantial problem in the United States. It has been estimated that over 50% of sewer overflows are a result of FOG blockages. In this work, a thorough laboratory study was undertaken to examine key variables that contribute to FOG deposit formation under controlled conditions. Physical and chemical properties and their interactions were evaluated and conditions that generated deposits that mimicked field FOG deposits were identified. It was found that 96 of the of 128 reaction conditions tested in the laboratory formed FOG deposits with similar physical and chemical characteristics as field FOG deposits. It was also found that FOG deposits can be created through fatty acid crystallization and not just saponification. Furthermore FOG deposits were found to be more complex than previously documented and contain free fatty acids, fatty acid metal salts, triacylglycerol's, diacylglycerol's and, monoacylglycerol's. Lastly it was found that FOG deposits that only contained saturated fatty acids were on average 2.1 times higher yield strength than deposits that contained unsaturated fatty acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photoelectrocatalytic degradation of oxalic acid by spray deposited nanocrystalline zinc oxide thin films

International Nuclear Information System (INIS)

Shinde, S.S.; Shinde, P.S.; Sapkal, R.T.; Oh, Y.W.; Haranath, D.; Bhosale, C.H.; Rajpure, K.Y.

2012-01-01

Highlights: ► Influence of substrate temperature onto the physico-chemical properties. ► Photochemical, structural, luminescent, optoelectrical and thermal properties. ► The kinetics of oxalic acid degradation with reaction mechanism. ► Extent of mineralization by COD and TOC. - Abstract: The high quality nano-crystalline zinc oxide thin films are deposited onto corning glasses by spray pyrolysis technique. The influence of reaction temperature onto their photoelectrochemical, structural, morphological, optoelectronic, luminescence and thermal properties has been investigated. The structural characteristics studied by X-ray diffractometry has complemented by resistivity measurements and UV–Vis spectroscopy. The photoelectrochemical activity shows enhancement in short circuit current (I sc = 0.357 mA) and open circuit voltage (V oc = 0.48 V). Direct band gap calculated by considering R and T values of ZnO thin films increases from 3.14–3.21 eV exhibiting a slight blue shift in band edge. Three characteristic luminescence peaks having near band-edge, blue and green emission are observed in the photoluminescence spectra. The specific heat and thermal conductivity study shows the phonon conduction behavior is dominant in films. Photocatalytic degradation of oxalic acid followed with reaction mechanism by using zinc oxide photoelectrode under solar illumination has been investigated.

The development of an approach to assess critical loads of acidity for woodland habitats in Great Britain

Directory of Open Access Journals (Sweden)

S. J. Langan

2004-01-01

Full Text Available Alongside other countries that are signatories to the UNECE Convention Long Range Transboundary on Air Pollution, the UK is committed to reducing the impact of air pollution on the environment. To advise and guide this policy in relation to atmospheric emissions of sulphur and nitrogen, a critical load approach has been developed. To assess the potential impact of these pollutants on woodland habitats a steady state, simple mass balance model has been parameterised. For mineral soils, a Ca:Al ratio in soil solution has been used as the critical load indicator for potential damage. For peat and organic soils critical loads have been set according to a pH criterion. Together these approaches have been used with national datasets to examine the potential scale of acidification in woodland habitats across the UK. The results can be mapped to show the spatial variability in critical loads of the three principal woodland habitat types (managed coniferous, managed broadleaved/ mixed woodland and unmanaged woodland. The results suggest that there is a wide range of critical loads. The most sensitive (lowest critical loads are associated with managed coniferous followed by unmanaged woodland on peat soils. Calculations indicate that at steady state, acid deposition inputs reported for 1995–1997 result in a large proportion of all the woodland habitats identified receiving deposition loads in excess of their critical load; i.e. critical loads are exceeded. These are discussed in relation to future modelled depositions for 2010. Whilst significant widespread negative impacts of such deposition on UK woodland habitats have not been reported, the work serves to illustrate that if acid deposition inputs were maintained and projected emissions reductions not achieved, the long-term sustainability of large areas of woodland in the UK could be compromised. Keywords: critical loads, acid deposition, acidification, woodland, simple mass balance model

Interactive Effects of Jasmonic Acid, Salicylic Acid, and Gibberellin on Induction of Trichomes in Arabidopsis1

Science.gov (United States)

Traw, M. Brian; Bergelson, Joy

2003-01-01

Leaf trichomes protect plants from attack by insect herbivores and are often induced following damage. Hormonal regulation of this plant induction response has not been previously studied. In a series of experiments, we addressed the effects of artificial damage, jasmonic acid, salicylic acid, and gibberellin on induction of trichomes in Arabidopsis. Artificial damage and jasmonic acid caused significant increases in trichome production of leaves. The jar1-1 mutant exhibited normal trichome induction following treatment with jasmonic acid, suggesting that adenylation of jasmonic acid is not necessary. Salicylic acid had a negative effect on trichome production and consistently reduced the effect of jasmonic acid, suggesting negative cross-talk between the jasmonate and salicylate-dependent defense pathways. Interestingly, the effect of salicylic acid persisted in the nim1-1 mutant, suggesting that the Npr1/Nim1 gene is not downstream of salicylic acid in the negative regulation of trichome production. Last, we found that gibberellin and jasmonic acid had a synergistic effect on the induction of trichomes, suggesting important interactions between these two compounds. PMID:14551332

LSD and Genetic Damage

Science.gov (United States)

Dishotsky, Norman I.; And Others

1971-01-01

Reviews studies of the effects of lysergic acid diethylamide (LSD) on man and other organisms. Concludes that pure LSD injected in moderate doses does not cause chromosome or detectable genetic damage and is not a teratogen or carcinogen. (JM)

1987 wet deposition temporal and spatial patterns in North America

Energy Technology Data Exchange (ETDEWEB)

Simpson, J.C.; Olsen, A.R.

1990-03-01

The focus of this report is on North American wet deposition temporal patterns from 1979 to 1987 and spatial patterns for 1987. The report investigates the patterns of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. Data are from the Acid Deposition System (ADS) for the statistical reporting of North American deposition data which includes the National Atmospheric Deposition Program/National Trends Network (NADP/NTN), the MAP3S precipitation chemistry network, the Utility Acid Precipitation Study Program (UAPSP), the Canadian Precipitation Monitoring Network (CAPMoN), and the daily and 4-weekly Acidic Precipitation in Ontario Study (APIOS-D and APIOS-C). Mosaic maps, based on surface estimation using kriging, display concentration and deposition spatial patterns of pH, hydrogen, sulfate, nitrate, ammonium, and calcium ion species for 1987 annual, winter, and summer periods. The temporal pattern analyses use a subset of 39 sites over a 9-year (1979--1987) period and an expanded subset of 140 sites with greater spatial coverage over a 6-year (1982--1987) period. 68 refs., 15 figs., 15 tabs.

MRI Overestimates Excitotoxic Amygdala Lesion Damage in Rhesus Monkeys

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Benjamin M. Basile

2017-06-01

Full Text Available Selective, fiber-sparing excitotoxic lesions are a state-of-the-art tool for determining the causal contributions of different brain areas to behavior. For nonhuman primates especially, it is advantageous to keep subjects with high-quality lesions alive and contributing to science for many years. However, this requires the ability to estimate lesion extent accurately. Previous research has shown that in vivo T2-weighted magnetic resonance imaging (MRI accurately estimates damage following selective ibotenic acid lesions of the hippocampus. Here, we show that the same does not apply to lesions of the amygdala. Across 19 hemispheres from 13 rhesus monkeys, MRI assessment consistently overestimated amygdala damage as assessed by microscopic examination of Nissl-stained histological material. Two outliers suggested a linear relation for lower damage levels, and values of unintended amygdala damage from a previous study fell directly on that regression line, demonstrating that T2 hypersignal accurately predicts damage levels below 50%. For unintended damage, MRI estimates correlated with histological assessment for entorhinal cortex, perirhinal cortex and hippocampus, though MRI significantly overestimated the extent of that damage in all structures. Nevertheless, ibotenic acid injections routinely produced extensive intentional amygdala damage with minimal unintended damage to surrounding structures, validating the general success of the technique. The field will benefit from more research into in vivo lesion assessment techniques, and additional evaluation of the accuracy of MRI assessment in different brain areas. For now, in vivo MRI assessment of ibotenic acid lesions of the amygdala can be used to confirm successful injections, but MRI estimates of lesion extent should be interpreted with caution.

Uranium deposits associated to tertiary acid volcanism of the Pena Blanca Sierra (Chihuahua, Mexico)

International Nuclear Information System (INIS)

Aniel, B.

1986-12-01

The uraniferous deposits located in the Sierra de Pena Blanca (Chihuahua, Mexico) are the consequence of successive events that modified acid volcanic rocks. The devitrification of the Nopal Formation, vitroclastic tuffs, is esential in the cooling history because it releases uranium that becomes available. The uranium present in fluids as uranylcarbonate complexes, precipitate along the lamellea of hematite (exsolutions of the ilmenites). The presence of sulfur causes the destabilization of the ilmenites with uranium oxide (pitchblende - titanium oxide - pyrite), the pseudomorph of magnetites (pitchblende - pyrite) and the transformation of hematite into pyrite. The silice coming from the kaolinization of feldspars recristallizes as microcristalline quartz so that the rock appears compact. Fractures cause the uplifting of the lower unit of Nopal formation. It has been altered to montmorillonite. A carbonatation of this tuff has been observed and these two types of alteration occur after kaolinization. The Escuadra formation overlies the Nopal formation. The deposition takes place on an eroded basement where a soil developed. The two formations will together undergo transformations due to the saturation level and the primary ore will be only oxidized or oxidized, transported and reconcentrated. Late and localized thermal activities have been observed and may be the result of tectonic movements occurring after the supergene modification [fr

Citric acid improves lead (pb) phytoextraction in brassica napus L. by mitigating pb-induced morphological and biochemical damages.

Science.gov (United States)

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. Copyright © 2014 Elsevier Inc. All rights reserved.

Mechanisms of fat, oil and grease (FOG) deposit formation in sewer lines.

Science.gov (United States)

He, Xia; de los Reyes, Francis L; Leming, Michael L; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J

2013-09-01

FOG deposits in sewer systems have recently been shown to be metallic salts of fatty acids. However, the fate and transport of FOG deposit reactant constituents and the complex interactions during the FOG deposit formation process are still largely unknown. In this study, batch tests were performed to elucidate the mechanisms of FOG deposit formation that lead to sanitary sewer overflows (SSOs). We report the first formation of FOG deposits on a concrete surface under laboratory conditions that mimic the formation of deposits in sewer systems. Results showed that calcium, the dominant metal in FOG deposits, can be released from concrete surfaces under low pH conditions and contribute to the formation process. Small amounts of additional oil to grease interceptor effluent substantially facilitated the air/water or pipe surface/water interfacial reaction between free fatty acids and calcium to produce surface FOG deposits. Tests of different fatty acids revealed that more viscous FOG deposit solids were formed on concrete surfaces, and concrete corrosion was accelerated, in the presence of unsaturated FFAs versus saturated FFAs. Based on all the data, a comprehensive model was proposed for the mechanisms of FOG deposit formation in sewer systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

Physicochemical aspects of decomposition of silica-alumina ores of argillites and green clays of Chashma-Sang Deposit of the Republic of Tajikistan by hydrochloric and nitric acids

International Nuclear Information System (INIS)

Kayumov, A.M.

2018-01-01

The purpose of work is to study the processes of decomposition of silica-alumina ores of argillites and green clays of Chashma-Sang Deposit of the Republic of Tajikistan by hydrochloric and nitric acids in temperature interval 20-98 deg C with the using of methods of selective extraction of valuable materials; elaboration of rational conditions of decomposition of raw material. Physicochemical properties of initial aluminium comprising ores, intermediate and final products of processing of argillites and green clays have been studied. Kinetic parameters of processes at acidic decomposition of argillites and green clays have been studied as well. The kinetic parameters of processes of decomposition of green clays and argillites by nitric and hydrochloric acids have been calculated. The flowsheet of complex processing of green clays and argillites of Chashma-Sang Deposit has been elaborated.

Manual resurfacing and trichloroacetic acid for the treatment of patients with widespread actinic damage. Clinical and histologic observations.

Science.gov (United States)

Cooley, J E; Casey, D L; Kauffman, C L

1997-05-01

A facial resurfacing regimen combining manual abrasion of the skin and 25% trichloroacetic acid has been reported to produce excellent results, but the histologic depth of injury produced by this technique has not been studied. To describe our experience with this technique treating patients with extensive actinic damage and to determine the histologic depth of injury produced. We treated 40 patients using manual resurfacing and trichloroacetic acid, primarily for widespread actinic keratoses. Resurfacing tools included silicone carbide sandpaper, drywall screen, electrocautery tip cleaners, abrasive pads, scalpel blades, and curettes. Four patients underwent sequential biopsies to evaluate the depth of wounding using this technique. Manual resurfacing combined with trichloroacetic acid consistently produced excellent cosmetic results and nearly complete eradication of actinic keratoses. Histologically, treated areas showed replacement of the dermal elastotic band by newly formed collagen, a significantly deeper level of wounding than the Jessner's/35% trichloroacetic acid peel. There was no evidence for foreign body granulomas clinically or histologically as a result of the abrasive materials. The deeper level of this peel explains the improved cosmetic outcome and greater eradication of actinic keratoses. This treatment is particularly well suited for patients with extensive photodamage and widespread actinic keratoses.

Rapid Deposition of Oxidized Biogenic Compounds to a Temperate Forest

Science.gov (United States)

Nguyen, Tran B.; Crounse, John D.; Teng, Alex P.; St. Clair, Jason M.; Paulot, Fabien; Wolfe, Glenn M.; Wennberg, Paul O.

2015-01-01

We report fluxes and dry deposition velocities for 16 atmospheric compounds above a southeastern United States forest, including: hydrogen peroxide (H2O2), nitric acid (HNO3), hydrogen cyanide (HCN), hydroxymethyl hydroperoxide, peroxyacetic acid, organic hydroxy nitrates, and other multifunctional species derived from the oxidation of isoprene and monoterpenes. The data suggest that dry deposition is the dominant daytime sink for small, saturated oxygenates. Greater than 6 wt %C emitted as isoprene by the forest was returned by dry deposition of its oxidized products. Peroxides account for a large fraction of the oxidant flux, possibly eclipsing ozone in more pristine regions. The measured organic nitrates comprise a sizable portion (15%) of the oxidized nitrogen input into the canopy, with HNO3 making up the balance. We observe that water-soluble compounds (e.g., strong acids and hydroperoxides) deposit with low surface resistance whereas compounds with moderate solubility (e.g., organic nitrates and hydroxycarbonyls) or poor solubility (e.g., HCN) exhibited reduced uptake at the surface of plants. To first order, the relative deposition velocities of water-soluble compounds are constrained by their molecular diffusivity. From resistance modeling, we infer a substantial emission flux of formic acid at the canopy level (approx. 1 nmol m(exp.-2)·s(exp.-1)). GEOS-Chem, awidely used atmospheric chemical transport model, currently underestimates dry deposition for most molecules studied in this work. Reconciling GEOS-Chem deposition velocities with observations resulted in up to a 45% decrease in the simulated surface concentration of trace gases.

2-Aminopurine hairpin probes for the detection of ultraviolet-induced DNA damage

International Nuclear Information System (INIS)

El-Yazbi, Amira F.; Loppnow, Glen R.

2012-01-01

Highlights: ► Molecular beacon with 2AP bases detects DNA damage in a simple mix-and-read assay. ► Molecular beacons with 2AP bases detect damage at a 17.2 nM limit of detection. ► The 2AP molecular beacon is linear over a 0–3.5 μM concentration range for damage. - Abstract: Nucleic acid exposure to radiation and chemical insults leads to damage and disease. Thus, detection and understanding DNA damage is important for elucidating molecular mechanisms of disease. However, current methods of DNA damage detection are either time-consuming, destroy the sample, or are too specific to be used for generic detection of damage. In this paper, we develop a fluorescence sensor of 2-aminopurine (2AP), a fluorescent analogue of adenine, incorporated in the loop of a hairpin probe for the quantification of ultraviolet (UV) C-induced nucleic acid damage. Our results show that the selectivity of the 2AP hairpin probe to UV-induced nucleic acid damage is comparable to molecular beacon (MB) probes of DNA damage. The calibration curve for the 2AP hairpin probe shows good linearity (R 2 = 0.98) with a limit of detection of 17.2 nM. This probe is a simple, fast and economic fluorescence sensor for the quantification of UV-induced damage in DNA.

Air pollution: Tropospheric ozone, and wet deposition of sulfate and inorganic nitrogen

Science.gov (United States)

John W. Coulston

2009-01-01

The influence of air pollutants on ecosystems in the United States is an important environmental issue. The term “air pollution” encompasses a wide range of topics, but acid deposition and ozone are primary concerns in the context of forest health. Acid deposition partially results from emissions of sulfur dioxide, nitrogen oxides, and ammonia that are deposited in wet...

Selective Electroless Silver Deposition on Graphene Edges

DEFF Research Database (Denmark)

Durhuus, D.; Larsen, M. V.; Andryieuski, Andrei

2015-01-01

We demonstrate a method of electroless selective silver deposition on graphene edges or between graphene islands without covering the surface of graphene. Modifications of the deposition recipe allow for decoration of graphene edges with silver nanoparticles or filling holes in damaged graphene...... on silica substrate and thus potentially restoring electric connectivity with minimal influence on the overall graphene electrical and optical properties. The presented technique could find applications in graphene based transparent conductors as well as selective edge functionalization and can be extended...

Inter- and intra-annual chemical variability during the ice-free season in lakes with different flushing rates and acid deposition histories.

Science.gov (United States)

Arnott, Shelley E; Dillon, Peter J; Somers, Keith; Keller, Bill

2003-01-01

Quantifying chemical variability in different lake types is important for the assessment of both chemical and biological responses to environmental change. For monitoring programs that emphasize a large number of lakes at the expense of frequent samples, high variability may influence how representative single samples are of the average conditions of individual lakes. Intensive temporal data from long-term research sites provide a unique opportunity to assess chemical variability in lakes with different characteristics. We compared the intra- and inter-annual variability of four acidification related variables (Gran alkalinity, pH, sulphate concentration, and total base cation concentration) in four lakes with different flushing rates and acid deposition histories. Variability was highest in lakes with high flushing rates and was not influenced by historic acid deposition in our study lakes. This has implications for the amount of effort required in monitoring programs. Lakes with high flushing rates will require more frequent sampling intervals than lakes with low flushing rates. Consideration of specific lake types should be included in the design of monitoring programs.

Advanced zirconia-coated carbonyl-iron particles for acidic magnetorheological finishing of chemical-vapor-deposited ZnS and other IR materials

Science.gov (United States)

Salzman, S.; Giannechini, L. J.; Romanofsky, H. J.; Golini, N.; Taylor, B.; Jacobs, S. D.; Lambropoulos, J. C.

2015-10-01

We present a modified version of zirconia-coated carbonyl-iron (CI) particles that were invented at the University of Rochester in 2008. The amount of zirconia on the coating is increased to further protect the iron particles from corrosion when introduced to an acidic environment. Five low-pH, magnetorheological (MR) fluids were made with five acids: acetic, hydrochloric, nitric, phosphoric, and hydrofluoric. All fluids were based on the modified zirconia-coated CI particles. Off-line viscosity and pH stability were measured for all acidic MR fluids to determine the ideal fluid composition for acidic MR finishing of chemical-vapor-deposited (CVD) zinc sulfide (ZnS) and other infrared (IR) optical materials, such as hot-isostatic-pressed (HIP) ZnS, CVD zinc selenide (ZnSe), and magnesium fluoride (MgF2). Results show significant reduction in surface artifacts (millimeter-size, pebble-like structures on the finished surface) for several standard-grade CVD ZnS substrates and good surface roughness for the non-CVD MgF2 substrate when MR finished with our advanced acidic MR fluid.

DNA damage by Auger emitters

International Nuclear Information System (INIS)

Martin, R.F.; d'Cunha, Glenn; Gibbs, Richard; Murray, Vincent; Pardee, Marshall; Allen, B.J.

1988-01-01

125 I atoms can be introduced at specific locations along a defined DNA target molecule, either by site-directed incorporation of an 125 I-labelled deoxynucleotide or by binding of an 125 I-labelled sequence-selective DNA ligand. After allowing accumulation of 125 I decay-induced damage to the DNA, application of DNA sequencing techniques enables positions of strand breaks to be located relative to the site of decay, at a resolution corresponding to the distance between adjacent nucleotides [0.34 nm]. Thus, DNA provides a molecular framework to analyse the extent of damage following [averaged] individual decay events. Results can be compared with energy deposition data generated by computer-simulation methods developed by Charlton et al. The DNA sequencing technique also provides information about the chemical nature of the termini of the DNA chains produced following Auger decay-induced damage. In addition to reviewing the application of this approach to the analysis of 125 I decay induced DNA damage, some more recent results obtained by using 67 Ga are also presented. (author)

Monosodium urate crystal deposition associated with the progress of radiographic grade at the sacroiliac joint in axial SpA: a dual-energy CT study.

Science.gov (United States)

Zhu, Junqing; Li, Aiwu; Jia, Ertao; Zhou, Yi; Xu, Juan; Chen, Shixian; Huang, Yinger; Xiao, Xiang; Li, Juan

2017-05-02

Previous studies have revealed that ankylosing spondylitis (AS), as the progenitor of axial spondyloarthritis (AxSpA), has been characterized by the insidiously progressive nature of sacroiliitis and spondylitis. Dual-energy computed tomography (DECT) has recently been used to analyse the deposition of monosodium urate (MSU) crystals with higher sensitivity and specificity. However, it remains unclear whether the existence of the MSU crystal deposition detected by DECT at the sacroiliac joint in patients with AxSpA also is associated with the existing structural damage. Here, we performed this study to show the DECT MSU crystal deposits in AxSpA patients without coexisting gout and to ascertain the relationship between the MSU crystal deposition and the structural joint damage of sacroiliac joints. One hundred and eighty-six AxSpA patients without coexisting gout were recruited. The plain radiographs of the sacroiliac joint were obtained, along with the DECT scans at the pelvis and the clinical variables. All statistics based on the left or right sacroiliac joint damage grading (0-4) were calculated independently. Bivariate analysis and ordinal logistic regression was performed between the clinical features and radiographic grades at the sacroiliac joint. At the pelvis, large quantities of MSU crystal deposition were found in patients with AxSpA. The average MSU crystal volume at the left sacroiliac joint, the right sacroiliac joint, and the pelvis were 0.902 ± 1.345, 1.074 ± 1.878, and 5.272 ± 9.044 cm 3 , values which were correlated with serum uric acid concentrations (r = 0.727, 0.740, 0.896; p sacroiliac joint damage. Further, the AxSpA duration, BASFI score, and the volume of MSU crystal at both sides of sacroiliac joint were associated with the progress of radiographic grade at the sacroiliac joints in the ordinal logistic models (left AOR = 1.180, 3.800, 1.920; right AOR = 1.190, 3.034, 1.418; p sacroiliac joint is associated

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

Science.gov (United States)

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.

Chemical and mineralogical changes of waste and tailings from the Murgul Cu deposit (Artvin, NE Turkey): implications for occurrence of acid mine drainage.

Science.gov (United States)

Sağlam, Emine Selva; Akçay, Miğraç

2016-04-01

Being one of the largest copper-producing resources in Turkey, the Murgul deposit has been a source of environmental pollution for very long time. Operated through four open pits with an annual production of about 3 million tons of ore at an average grade of about 0.5% Cu, the deposit to date has produced an enormous pile of waste (exceeding 100 million tons) with tailings composed of 36 % SiO2, 39% Fe2O3 and 32% S, mainly in the form of pyrite and quartz. Waters in the vicinity of the deposit vary from high acid-acid (2.71-3.85) and high-extremely metal rich (34.48-348.12 mg/l in total) in the open pits to near neutral (6.51-7.83) and low metal (14.39-973.52 μg/l in total) in downstream environments. Despite low metal contents and near neutral pH levels of the latter, their suspended particle loads are extremely high and composed mainly of quartz and clay minerals with highly elevated levels of Fe (3.5 to 24.5% Fe2O3; 11% on average) and S (0.5 to 20.6% S; 7% on average), showing that Fe is mainly in the form of pyrite and lesser hematite. They also contain high concentrations of As, Au, Ba, Cu, Pb, and Zn. Waters collected along the course of polluted drainages are supersaturated with respect to Fe phases such as goethite, hematite, maghemite, magnetite, schwertmannite and ferrihydrite. Secondary phases such as Fe-sulphates are only found near the pits, but not along the streams due to neutral pH conditions, where pebbles are covered and cemented by Fe-oxides and hydroxides indicating that oxidation of pyrite has taken place especially at times of low water load. It follows, then, that the pyrite-rich sediment load of streams fed by the waste of the Murgul deposit is currently a big threat to the aquatic life and environment and will continue to be so even after the closure of the deposit. In fact, the oxidation will be enhanced and acidity increased due to natural conditions, which necessitates strong remedial actions to be taken.

Effects and quantification of acid runoff from sulfide-bearing rock deposited during construction of Highway E18, Norway

Science.gov (United States)

Hindar, Atle; Nordstrom, D. Kirk

2015-01-01

The Highway E18 between the cities of Grimstad and Kristiansand, southern Norway, constructed in the period 2006–2009, cuts through sulfide-bearing rock. The geology of this area is dominated by slowly-weathering gneiss and granites, and oxidation of fresh rock surfaces can result in acidification of surface water. Sulfide-containing rock waste from excavations during construction work was therefore deposited in three waste rock deposits off-site. The deposits consist of 630,000–2,360,000 metric tons of waste rock material. Shell sand and limestone gravel were added in layers in adequate amounts to mitigate initial acid runoff in one of the deposits. The shell sand addition was not adequate in the two others. The pH in the effluents from these two was reduced from 4.9–6.5 to 4.0–4.6, and Al concentrations increased from below 0.4 mg/L to 10–20 mg/L. Stream concentrations of trace metals increased by a factor of 25–400, highest for Ni, and then in decreasing order for Co, Mn, Cd, Zn and Cu. Concentrations of As, Cr and Fe remained unchanged. Ratios of Co/Ni and Cd/Zn indicate that the metal sources for these pair of metals are sphalerite and pyrite, respectively. Based on surveys and established critical limits for Al, surface waters downstream became toxic to fish and invertebrates. The sulfur release rates were remarkably stable in the monitoring period at all three sites. Annual sulfur release was 0.1–0.4% of the total amount of sulfur in the deposit, indicating release periods of 250–800 years. Precipitates of Al-hydroxysulfates, well-known from mining sites, were found at the base of the deposits, in streams and also along the ocean shore-line. The effects of added neutralization agents in the deposits and in treatment areas downstream gradually decreased, as indicated by reduced stream pH over time. Active measures are needed to avoid harmful ecological effects in the future.

RBS and NRA damage analysis on PFA films bombarded with hydrogen

Energy Technology Data Exchange (ETDEWEB)

Parada, Marco A.; Petchevist, Paulo C.D.; Minamisawa, Renato A.; Almeida, Adelaide de [Sao Paulo Univ., SP (Brazil). Inst. de Fisica]. E-mail: dalmeida@ffclrp.usp.br; Muntele, Claudiu I.; Zimmerman, Robert L.; Ila, Daryush [A and M University, Normal, AL (United States). Center for Irradiation of Materials]. E-mail: ila@cim.aamu.edu

2005-07-01

The fluoropolymer PFA (Tetrafluoroethylene-per-fluoromethoxy ethylene) is a conventional thermoplastic used in civil engineering applications such as anti-adherent coatings and concrete additives. It is also candidate materials for radiation dosimetry with applications in medical physics. When such a polymer is exposed to ionizing radiation, it can suffers damages that depend on the type, energy, and intensity of the radiation. We present results on the damage caused by 1 MeV protons at fluences of 10{sup 13}, 10{sup 14}, 10{sup 15}, and 10{sup 16} protons/cm{sup 2}. The energy deposited during such hydrogen bombardment breaks the polymeric chains with the release of fluorine in amounts directly proportional to the amount of deposited energy. Virgin samples were first analyzed by RBS. Subsequent damage was then profiled by monitoring the alpha emission spectrum, resulting from the nuclear reaction: {sup 19}F(p,{alpha}{gamma}){sup 16}O induced by 1.38 MeV protons on the remaining fluorine content of damaged polymer samples. (author)

Multi-material poly(lactic acid) scaffold fabricated via fused deposition modeling and direct hydroxyapatite injection as spacers in laminoplasty

Science.gov (United States)

Syuhada, Ghifari; Ramahdita, Ghiska; Rahyussalim, A. J.; Whulanza, Yudan

2018-02-01

Nowadays, additive manufacturing method has been used extensively to realize any product with specific attributes rather than the conventional subtractive manufacturing method. For instance, the additive manufacturing has enable us to construct a product layer-by-layer by successively depositing several materials in one session and one platform. This paper studied the properties of a 3D printed scaffold fabricated through Poly(Lactic-acid) (PLA) deposition modelling in combination with injectable hydroxyapatite (HA)/alginate as cell carrier. The scaffold was designed to serve as a spacer in cervical laminoplasty. Therefore, a series of test were conducted to elaborate the mechanical property, porosity and in-vitro toxicity testing. The results showed that the method is reliable to fabricate the scaffold as desired although the toxicity test needs more confirmation.

Gamma Amino Butyric Acid Attenuates Liver and Kidney Damage Associated with Insulin Alteration in γ-Irradiated and Streptozotocin-Treated Rats

International Nuclear Information System (INIS)

Saada, H.N.; Eltahawy, N.A.; Hammad, A.S.; Morcos, N.Y.S.

2016-01-01

Gamma aminobutyric acid (GABA) is one of the inhibitory neurotransmitters that may have the ability to relive the intensity of stress. The aim of the current study was to evaluate the role of γ-amino butyric acid (GABA) in modulating insulin disturbance associated with liver and kidney damage in γ-irradiated and streptozotocin-treated rats. Irradiation was performed by whole body exposure to 6 Gy from a Cs-137 source. Streptozotocin (STZ) was administered in a single intraperitoneal dose (60 mg/kg body weight). GABA (200 mg/Kg body weight/day) was administered daily via gavages during 3 weeks to γ-irradiated and STZ-treated-rats. The results obtained showed that γ-irradiation induced hyperglycemia, hyperinsulinaemia and insulin resistance (similar to type 2 Diabetes), while STZ-treatment produced hyperglycemia, insulin deficiency with no insulin resistance detected (similar to type 1 Diabetes). In both cases, significant increases of alanine amino transferase (ALT) and aspartate amino transferase (AST) activities, urea and creatinine levels were recorded in the serum. These changes were associated with oxidative damage to the liver and kidney tissues notified by significant decreases of superoxide dismutase (SOD ), catalase and glutathione peroxidase ( GSH-Px) activities in parallel to significant increases of malondialdehyde (MDA) and advanced oxidation protein products ( AOPP) levels. The administration of GABA to irradiated as well as STZ-treated rats regulated insulin and glucose levels, minimized oxidative stress and reduced the severity of liver and kidney damage. It could be concluded that GABA could be a useful adjunct to reduce some metabolic complications associated with insulin deficiency and insulin resistance

Supplementation with beta-hydroxy-beta-methylbutyrate (HMB) and alpha-ketoisocaproic acid (KIC) reduces signs and symptoms of exercise-induced muscle damage in man.

Science.gov (United States)

van Someren, Ken A; Edwards, Adam J; Howatson, Glyn

2005-08-01

This study examined the effects of beta-hydroxyl-beta-methylbutyrate (HMB) and alpha-ketoisocaproic acid (KIC) supplementation on signs and symptoms of exercise-induced muscle damage following a single bout of eccentrically biased resistance exercise. Six non-resistance trained male subjects performed an exercise protocol designed to induce muscle damage on two separate occasions, performed on the dominant or non-dominant arm in a counter-balanced crossover design. Subjects were assigned to an HMB/KIC (3 g HMB and 0.3 g alpha-ketoisocaproic acid, daily) or placebo treatment for 14 d prior to exercise in the counter-balanced crossover design. One repetition maximum (1RM), plasma creatine kinase activity (CK), delayed onset muscle soreness (DOMS), limb girth, and range of motion (ROM) were determined pre-exercise, at 1h, 24 h, 48 h, and 72 h post-exercise. DOMS and the percentage changes in 1RM, limb girth, and ROM all changed over the 72 h period (P HMB//IC supplementation attenuated the CK response, the percentage decrement in 1RM, and the percentage increase in limb girth (P HMB/KIC treatment. In conclusion, 14 d of HMB and KIC supplementation reduced signs and symptoms of exercise-induced muscle damage in non-resistance trained males following a single bout of eccentrically biased resistance exercise.

Piper sarmentosum is comparable to glycyrrhizic acid in reducing visceral fat deposition in adrenalectomised rats given dexamethasone.

Science.gov (United States)

Fairus, A; Ima Nirwana, S; Elvy Suhana, M R; Tan, M H; Santhana, R; Farihah, H S

2013-01-01

Visceral obesity may be due to the dysregulation of cortisol production or metabolism that lead to metabolic disease. In adipose tissue, the enzyme 11beta-hydroxysteroid dehydrogenase type 1 regulates cortisol metabolism (11beta-HSD1). A previous study showed an increase in the visceral fat deposition in adrenalectomised rats given intramuscular dexamethasone. Glycyrrhizic acid (GCA) has been shown to reduce fat deposition because it is a known potent inhibitor of the 11beta-HSD1 enzyme. Piper sarmentosum (PS) is an edible medicinal plant commonly used in Asia as traditional medicine for treating diabetes, hypertension and joint pains. In this study, we determined the effects of PS extract on the disposition and morphology of perirenal adipocytes of adrenalectomised rats given intramuscular dexamethasone. A total of 21 male Spraque Dawley rats were adrenalectomised and given intramuscular dexamethasone, 120 μg/kg/day. These rats were further divided into three groups: adrenalectomised control (ADR+Dexa; n=7), GCA-treated (ADR+Dexa+GCA; dose=240 mg/kg/day; n=7) and PS-treated (ADR+Dexa+PS; dose=125 mg/kg/day; n=7) groups. The various treatments were given via gastric gavage following 2 weeks of adrenalectomy. Treatment with PS extract for 8 weeks showed decreased deposition of perirenal adipocytes which was similar to the GCA-treated group. However, PS-treated rats had thinner adipocyte membrane compared with that of the GCA-treated group. In conclusion, PS extract decreased perirenal fat deposition and reduced the diameter of the adipocyte membrane. However, the mechanisms of action needed further study.

Actual implications of industrial smoke damage to forests

Energy Technology Data Exchange (ETDEWEB)

Zieger, E

1955-01-01

General problems of smoke-induced damages, diagnosis, and control methods are reviewed. Damages caused by etching of leaves and needles are mostly of an acute and local character. Damages due to disturbed assimilation, caused primarily by sulfur dioxide, are of the greatest importance economically. Sulfur dioxide is less harmful in winter and during night hours. Acids and sulfur dioxide both turn the soil acid, and affect the edaphon. Such damages are primarily of chronic character. Different diagnostic methods such as plant, soil, and air analyses should be combined to obtain reliable results. Due to the complexity of the processes involved in smoke damages, biological tests are best in diagnosis. The sunlight test exploits the fact that branches cut from smoke-damaged trees lose their needles more readily than such from intact trees. Haertels turbidity test is based on the increased wax secretion by smoke-damaged needles. The appraisal of damages is made by evaluation of the economic losses after the limitation of the smoke-affected area. The possible control measures in forestry are the breeding of smoke-resistant species and liming, while the pollution control techniques presently available in industry are unsatisfactory, the major problems being caused by sulfur dioxide. Standardization of thresholds and maximum allowable concentrations, as well as cooperation of forestry and industries are imperative. 12 references.

Atmospheric deposition and canopy exchange processes in alpine forest ecosystems (northern Italy)

Energy Technology Data Exchange (ETDEWEB)

Balestrini, R. [Water Research Institute, Brugherio (Italy); Tagliaferri, A. [Regional Forestry Board (Italy)

2001-07-01

Throughfall and bulk precipitation chemistry were studied for five years (June 1994-May 1999) at two high elevation forest sites (Val Gerola and Val Masino) which were known to differ in terms of tree health, as assessed by live crown condition. The ion concentration of bulk precipitation samples did not differ significantly between sites, except for Mg{sup 2+}, while the throughfall concentrations differed in the measured values of H{sup +}, N-NO{sub 3}{sup -}, Cl{sup -}, Na{sup +}, K{sup +}, DOC and weak organic acids. The results of the application of the canopy exchange model indicated a higher contribution from the dry deposition of N-NO{sub 3}{sup -}, N-NH{sub 4}{sup +} and H{sup +} at Val Gerola, where the damage symptoms were more evident. In addition, the canopy leaching of Ca{sup 2+}, K{sup +} and weak organic acids were 47%, 21% and 27% higher at Val Gerola than at Val Masino. Annual SO{sub 4}{sup 2-} deposition fluxes (21.3kg ha{sup -1}yr{sup -1} at Val Masino and 23.6kgha{sup -1}yr{sup -1} at Val Gerola) were similar to those reported for moderately polluted European and U.S. sites. Annual N loads were 13.6 and 13.1kgha{sup -1}yr{sup -1} in the bulk input, and 15.0 and 18.0kgha{sup -1}yr{sup -1} in throughfall inputs, at Val Masino and Val Gerola, respectively. The contribution of the organic fraction to the total N atmospheric deposition load is significant, constituting 17% of the bulk flux and 40% of the throughfall flux. Measured nitrogen loads exceed the critical nutrient loads by several kgNha{sup -1} at both stations. In particular the nitrogen throughfall load at Val Gerola was about 3 times higher than the critical values. (author)

The Coupling Effect Research of Ash Deposition and Condensation in Low Temperature Flue Gas

Directory of Open Access Journals (Sweden)

Lei Ma

2016-01-01

Full Text Available Ash deposition is a key factor that deteriorates the heat transfer performance and leads to higher energy consumption of low pressure economizer working in low temperature flue gas. In order to study the ash deposition of heat exchange tubes in low temperature flue gas, two experiments are carried out with different types of heat exchange tubes in different flue gas environments. In this paper, Nusselt Number Nu and fouling factor ε are calculated to describe the heat transfer characteristics so as to study the ash deposition condition. The scanning electron microscope (SEM is used for the analysis of ash samples obtained from the outer wall of heat exchange tubes. The dynamic process of ash deposition is studied under different temperatures of outer wall. The results showed that ash deposition of heat exchanger will achieve a stable state in constant flue gas environment. According to the condition of condensation of acid vapor and water vapor, the process of ash deposition can be distinguished as mere ash deposition, acid-ash coupling deposition, and acid-water-ash coupling deposition.

Genetic effects from internally deposited radionuclides

International Nuclear Information System (INIS)

Anon.

1987-01-01

It was learned in the late 1920's that ionizing radiation could produce genetic effects such as gene mutations and chromosome aberrations. However, at least until 1945, the focus on interest in radiation protection was primarily on somatic effects manifested in the individual exposed. Studies of the genetic effects of radiation using drosophila, however, refocused attention on effects transmitted to the exposed individuals offspring and concern over fallout in the 1950's resulted in efforts to estimate the genetic effects from exposure of human populations to internally deposited radionuclides. No human populations have been identified with burdens of internally deposited radioactive materials which have been shown to produce evidence of transmissible genetic damage. As a result, the research approach has been one in which macromolecular, cellular, and whole animal genetic studies have been combined to estimate genetic effects on humans following the deposition of radioactive materials in the body. The purpose of this report is to update the information available from animal and cellular experiments that relates genetic effects to deposited activity and dose from internally deposited radioactive materials

Amelioration of radiation induced DNA damage and biochemical alterations by Punica Granatum (L) extracts and synthetic ellagic acid in Swiss albino mice

International Nuclear Information System (INIS)

Satheesh Kumar Bhandary, B.; Sharmila, K.P.; Suchetha Kumari, N.; Vadisha Bhat, S.; Sherly, Sharmila; Sanjeev, Ganesh

2013-01-01

Radiation therapy has been used in cancer treatment for many decades; Although effective in killing tumor cells, ROS produced in radiotherapy threaten the integrity and survival of surrounding normal cells. ROS are scavenged by radioprotectors before they can interact with biochemical molecules, thus reducing harmful effects of radiation. The pomegranate, Punica granatum L., an ancient, mystical, and highly distinctive fruit, is the predominant member of the Punicaceae family. It is used in several systems of medicine for a variety of ailments. The objective of the present study was to investigate the protective effects of ethanolic extracts of pomegranate whole fruit (EPWF) and seeds (EPS) and Synthetic Ellagic acid (EA) against Electron Beam Radiation (EBR) induced DNA damage and biochemical alterations in Swiss Albino mice. The extracts and synthetic compound were assessed for its radical scavenging property by DPPH radical scavenging and Ferric Reducing Antioxidant Power assays. The animals were treated with 200 mg/kg body wt. of pomegranate extracts and Ellagic acid for 15 days before exposure to 6 Gy of EBR. Radiation induced DNA damage was assessed by comet assay in the peripheral blood lymphocytes of mice. The biochemical estimations were carried out in the serum and RBC lysate of the animals. The plant extracts and synthetic compound exhibited good radical scavenging and reducing properties.The pretreated animals before irradiation caused a reduction in the comet length, olive tail moment, % DNA in tail when compared to irradiated group. The biochemical parameters such as lipid peroxidation was significantly depleted in the treated groups when compared to irradiated group followed by significant elevation in reduced glutathione. Our findings indicate the ameliorating effects of pomegranate extracts and synthetic ellagic acid on radiation induced DNA damage and biochemical changes in mice may be due to its free radical scavenging and increased antioxidant

Correlating optical damage threshold with intrinsic defect populations in fused silica as a function of heat treatment temperature

Energy Technology Data Exchange (ETDEWEB)

Shen, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Matthews, M. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Elhadj, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Miller, P. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nelson, A. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hamilton, J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2013-04-03

Here, chemical vapor deposition (CVD) is used for the production of fused silica optics in high-power laser applications. However, relatively little is known about the ultraviolet laser damage threshold of CVD films and how they relate to intrinsic defects produced during deposition. We present here a study relating structural and electronic defects in CVD films to 355 nm pulsed-laser damage threshold as a function of post-deposition annealing temperature (T_HT). Plasma-enhanced CVD based on SiH₄/N₂O under oxygen-rich conditions was used to deposit 1.5, 3.1 and 6.4 µm thick films on etched SiO2 substrates. Rapid annealing was performed using a scanned CO2 laser beam up to T_HT ~ 2100 K. The films were then characterized using x-ray photoemission spectroscopy, Fourier transform infrared spectroscopy (FTIR) and photoluminescence spectroscopy. A gradual transition in the damage threshold of annealed films was observed for T_HT values up to 1600 K, correlating with a decrease in non-bridging silanol and oxygen deficient centres. An additional sharp transition in damage threshold also occurs at ~1850 K indicating substrate annealing. Based on our results, a mechanism for damage-related defect annealing is proposed, and the potential of using high-T_HT CVD SiO₂ to mitigate optical damage is also discussed.

Responses of Soil Acid Phosphomonoesterase Activity to Simulated Nitrogen Deposition in Three Forests of Subtropical China

Institute of Scientific and Technical Information of China (English)

HUANG Wen-Juan; LIU Shi-Zhong; CHU Guo-Wei; ZHANG De-Qiang; LI Yue-Lin; LU Xian-Kai; ZHANG Wei; HUANG Juan; D. OTIENO; Z. H. XU; LIU Ju-Xiu

2012-01-01

Soil acid phosphomonoesterase activity (APA) plays a vital role in controlling phosphorus (P) cycling and reflecting the current degree of P limitation Responses of soil APA to elevating nitrogen (N) deposition are important because of their potential applications in addressing the relationship between N and P in forest ecosystems.A study of responses of soll APA to simulated N deposition was conducted in three succession forests of subtropical China.The three forests include a Masson pine (Pinus massoniana) forest (MPF)—pioneer community,a coniferous and broad-leaved mixed forest (MF)—transition community and a monsoon evergreen broadleaved forest (MEBF)—climax community.Four N treatments were designed for MEBF:control (without N added),low-N (50 kg N ha-1 year-1),and medium-N (100 kg N ha-1 year-1) and high-N (150 kg N ha-1 year-1),and only three N treatments (i.e.,control,low-N,mediun-N) were established for MPF and MF.Results showed that soil APA was highest in MEBF.followed by MPF and MF.Soil APAs in both MPF and MF were not influenced by low-N treatments but depressed in medium-N trcatments.However,soil APA in MEBF exhibited negative responses to high N additions,indicating that the environment of enhanced N depositions would reduce P supply for the mature forest ecosystem.Soil APA and its responses to N additions in subtropical forests were closely related to the succession stages in the forests.

The law concerning indemnification of nuclear damage

International Nuclear Information System (INIS)

1977-01-01

This Law aims at determining the basic system concerning indemnification for nuclear damage caused by the operation of reactors, fabrication, reprocessing and use of nuclear fuel materials as well as the transportation, storing or disposal of such materials or those contaminated by such materials (including fission products) accompanying these operations in view of protecting the sufferers and contributing to the wholesome development of atomic energy enterprises. The ''nuclear damage'' referred to in this Law is the damages caused by the action during the process of fission of nuclear fuel materials or the action of radiation or the poisonous action of said nuclear fuel materials or matters contaminated by said materials (those causing poisoning or deuteropathy in human bodies by taking in or inhaling such materials). Upon giving nuclear damage by the operation of reactors and others, the atomic energy entrepreneurs concerned are responsible for indemnifying the damage. Atomic energy entrepreneurs should not operate reactors without first taking the measures for indemnifying nuclear damages. Said measures are conclusion of nuclear damage indemnification responsibility insurance contract and nuclear damage indemnification contract or deposit, by which 6,000 million yen may be earmarked for such indemnification per factory, place of business or nuclear ship

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat transfer surfaces

International Nuclear Information System (INIS)

Burgmayer, P.; Crovetto, R.; Turner, C.; Klimas, S.

1998-01-01

The effectiveness of three different dispersants - a polyphosphonic acid (PIPPA); a polymethacrylic acid (PMA); and a hydroxyethylidene methacrylic acid (HEME) - at controlling magnetite deposition has been examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products with a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using a 59-Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any impact on deposition under single-phase forced-convective flow. (author)

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat-transfer surfaces

International Nuclear Information System (INIS)

Burgmayer, P.; Crovetto, R.; Turner, C.; Klimas, S.J.

1999-07-01

The effectiveness of 3 different dispersants-a polyphosphonic acid (PIPPA), a polymethacrylic acid (PMA), and a hydroxyethylidene methacrylic acid (HEME)-at controlling magnetite deposition was examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products of a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using an 59 Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any effect on deposition under single-phase forced-convective flow. (author)

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat transfer surfaces

Energy Technology Data Exchange (ETDEWEB)

Burgmayer, P.; Crovetto, R. [Betz Dearborn Labs., Revose, PA (United States); Turner, C.; Klimas, S. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

1998-07-01

The effectiveness of three different dispersants - a polyphosphonic acid (PIPPA); a polymethacrylic acid (PMA); and a hydroxyethylidene methacrylic acid (HEME) - at controlling magnetite deposition has been examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products with a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using a 59-Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any impact on deposition under single-phase forced-convective flow. (author)

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat-transfer surfaces

Energy Technology Data Exchange (ETDEWEB)

Burgmayer, P.; Crovetto, R. [Betz Dearborn Labs., Revose, PA (United States); Turner, C.; Klimas, S.J

1999-07-01

The effectiveness of 3 different dispersants-a polyphosphonic acid (PIPPA), a polymethacrylic acid (PMA), and a hydroxyethylidene methacrylic acid (HEME)-at controlling magnetite deposition was examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products of a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using an {sup 59}Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any effect on deposition under single-phase forced-convective flow. (author)

Exercise-induced muscle damage is reduced in resistance-trained males by branched chain amino acids: a randomized, double-blind, placebo controlled study

Directory of Open Access Journals (Sweden)

Howatson Glyn

2012-07-01

Full Text Available Abstract Background It is well documented that exercise-induced muscle damage (EIMD decreases muscle function and causes soreness and discomfort. Branched-chain amino acid (BCAA supplementation has been shown to increase protein synthesis and decrease muscle protein breakdown, however, the effects of BCAAs on recovery from damaging resistance training are unclear. Therefore, the aim of this study was to examine the effects of a BCAA supplementation on markers of muscle damage elicited via a sport specific bout of damaging exercise in trained volunteers. Methods Twelve males (mean ± SD age, 23 ± 2 y; stature, 178.3 ± 3.6 cm and body mass, 79.6 ± 8.4 kg were randomly assigned to a supplement (n = 6 or placebo (n = 6 group. The damaging exercise consisted of 100 consecutive drop-jumps. Creatine kinase (CK, maximal voluntary contraction (MVC, muscle soreness (DOMS, vertical jump (VJ, thigh circumference (TC and calf circumference (CC were measured as markers of muscle damage. All variables were measured immediately before the damaging exercise and at 24, 48, 72 and 96 h post-exercise. Results A significant time effect was seen for all variables. There were significant group effects showing a reduction in CK efflux and muscle soreness in the BCAA group compared to the placebo (P Conclusion The present study has shown that BCAA administered before and following damaging resistance exercise reduces indices of muscle damage and accelerates recovery in resistance-trained males. It seems likely that BCAA provided greater bioavailablity of substrate to improve protein synthesis and thereby the extent of secondary muscle damage associated with strenuous resistance exercise. Clinical Trial Registration Number: NCT01529281.

Determination of furan precursors and some thermal damage markers in baby foods: ascorbic acid, dehydroascorbic acid, hydroxymethylfurfural and furfural.

Science.gov (United States)

Mesías-García, Marta; Guerra-Hernández, Eduardo; García-Villanova, Belén

2010-05-26

The presence of ascorbic acid (AA), vitamin C (AA + dehydroascorbic acid (DHAA)) and furfural as potential precursors of furan in commercial fruit and vegetable jarred baby food was studied. Hydroxymethylfurfural (HMF) was also determined and used, together with furfural levels, as markers of thermal damage. AA, calculated DHAA and vitamin C values ranged between 22.4 and 103, 2.9 and 13.8, and 32.1 and 113.2 mg/100 g, respectively, in fruit-based baby food. However, no trace of AA was found in the vegetable-based baby food samples tested, probably because these samples are not enriched in vitamin C and the content of this vitamin in fresh vegetables is destroyed during processing. Furfural values ranged from not detected to 236 microg/100 g, being higher in vegetable samples than in fruit samples possibly because of greater AA degradation favored by a higher pH in the vegetable samples. HMF values (range: not detected-959 microg/100 g), however, were higher in the fruit samples, probably due to greater carbohydrate content degradation and as a consequence of the Maillard reaction, favored by a lower pH in these samples. According to these results, HMF would be the optimum indicator of thermal treatment for fruits, and furfural for vegetables. The higher furfural content of vegetable baby food could be considered an index of greater AA degradation and, therefore, the furan content might be higher in this kind of sample than in fruit-based baby food.

Characterization of chemically deposited low-cost 2-6 thin films solar cells : modifying effects with catalytic silicotungstic acid (STA)

Energy Technology Data Exchange (ETDEWEB)

Petuenju, E.N.; Savadogo, O. [Ecole Polytechnique de Montreal, Montreal, PQ (Canada). Laboratoire de nouveaux materiaux pour l' energie et l' electrochimie

2008-07-01

This paper described some properties of cadmium sulphide (CdS) thin films that were chemically deposited on a silicon wafer for solar cell and optoelectronic applications. The as-deposited films were thermally annealed and characterized through structural, electrical, optical, and spectroscopic methods. The modifying effects of silicotungstic acid (STA) showed promising characteristics for various applications, including X- and gamma-ray detector devices. The films were characterized by X-rays Photoelectron Spectroscopy, Scanning Electron Microscopy, X-ray Diffraction, and Photoluminescence. Ellipsometry measurements were used to determine the thickness of the sample. The study showed that there is no significant effect of the addition of 10-4 M of STA on the thickness of the film. This might be due to the low concentration of STA. No significant difference was noted for samples deposited with and without STA. In both cases the crystallite size of the sample was estimated to be lower than 1.5 microns. The CdS/Si and CdS(STA)/Si samples were annealed at 360 degrees C for 12 hours. The samples prepared with and without STA had the same structure. CdS deposited without and STA exhibited a mixed hexagonal and cubic structure, most likely because the annealing temperature of the sample was very close to the transition temperature of the cubic structure to the hexagonal structure. 3 refs., 1 tab., 3 figs.

Deoxyribonucleic Acid Damage and Repair: Capitalizing on Our Understanding of the Mechanisms of Maintaining Genomic Integrity for Therapeutic Purposes

Directory of Open Access Journals (Sweden)

Jolene Michelle Helena

2018-04-01

Full Text Available Deoxyribonucleic acid (DNA is the self-replicating hereditary material that provides a blueprint which, in collaboration with environmental influences, produces a structural and functional phenotype. As DNA coordinates and directs differentiation, growth, survival, and reproduction, it is responsible for life and the continuation of our species. Genome integrity requires the maintenance of DNA stability for the correct preservation of genetic information. This is facilitated by accurate DNA replication and precise DNA repair. DNA damage may arise from a wide range of both endogenous and exogenous sources but may be repaired through highly specific mechanisms. The most common mechanisms include mismatch, base excision, nucleotide excision, and double-strand DNA (dsDNA break repair. Concurrent with regulation of the cell cycle, these mechanisms are precisely executed to ensure full restoration of damaged DNA. Failure or inaccuracy in DNA repair contributes to genome instability and loss of genetic information which may lead to mutations resulting in disease or loss of life. A detailed understanding of the mechanisms of DNA damage and its repair provides insight into disease pathogeneses and may facilitate diagnosis and the development of targeted therapies.

Depth distribution of displacement damage in α-iron under triple beam ion irradiation

International Nuclear Information System (INIS)

Horton, L.L.; Bentley, J.; Jesser, W.A.

1981-01-01

The depth dependence of the defect structures was determined for iron irradiated at 850 0 K with 4 MeV Fe 2+ and energetic helium and deuteron ions to 10 dpa and fusion levels of helium and deuterium. From the damage profiles, a sectioning depth of 0.9 μm was selected for studies of iron and bcc iron alloys, such as ferritic steels, utilizing similar irradiation parameters. A comparison of the experimental damage profile to the deposited energy and deposited ion profiles calculated by E-DEP-1 indicated a possible overestimate of the LSS stopping power of at least 22%

Formulation of porous poly(lactic-co-glycolic acid) microparticles by electrospray deposition method for controlled drug release

Energy Technology Data Exchange (ETDEWEB)

Hao, Shilei; Wang, Yazhou; Wang, Bochu, E-mail: wangbc2000@126.com; Deng, Jia; Zhu, Liancai; Cao, Yang

2014-06-01

In the present study, the electrospray deposition was successfully applied to prepare the porous poly(lactic-co-glycolic acid) (PLGA) microparticles by one-step processing. Metronidazole was selected as the model drug. The porous PLGA microparticles had high drug loading and low density, and the porous structure can be observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The production time has been shortened considerably compared with that of the traditional multi-emulsion method. In addition, no chemical reaction occurred between the drug and polymer in the preparation of porous microparticles, and the crystal structure of drug did not change after entrapment into the porous microparticles. The porous microparticles showed a sustained release in the simulated gastric fluid, and the release followed non-Fickian or case II transport. Furthermore, porous microparticles showed a slight cytotoxicity in vitro. The results indicated that electrospray deposition is a good technique for preparation of porous microparticles, and the low-density porous PLGA microparticles has a potential for the development of gastroretentive systems or for pulmonary drug delivery. - Highlights: • The porous PLGA microparticles were successfully prepared by the electrospray deposition method at one step. • The porous microparticles had high loading capacity and low density. • The microparticle showed a sustained release in the simulated gastric liquid. • The microparticles showed a slight cytotoxicity in vitro.

Formulation of porous poly(lactic-co-glycolic acid) microparticles by electrospray deposition method for controlled drug release

International Nuclear Information System (INIS)

Hao, Shilei; Wang, Yazhou; Wang, Bochu; Deng, Jia; Zhu, Liancai; Cao, Yang

2014-01-01

In the present study, the electrospray deposition was successfully applied to prepare the porous poly(lactic-co-glycolic acid) (PLGA) microparticles by one-step processing. Metronidazole was selected as the model drug. The porous PLGA microparticles had high drug loading and low density, and the porous structure can be observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The production time has been shortened considerably compared with that of the traditional multi-emulsion method. In addition, no chemical reaction occurred between the drug and polymer in the preparation of porous microparticles, and the crystal structure of drug did not change after entrapment into the porous microparticles. The porous microparticles showed a sustained release in the simulated gastric fluid, and the release followed non-Fickian or case II transport. Furthermore, porous microparticles showed a slight cytotoxicity in vitro. The results indicated that electrospray deposition is a good technique for preparation of porous microparticles, and the low-density porous PLGA microparticles has a potential for the development of gastroretentive systems or for pulmonary drug delivery. - Highlights: • The porous PLGA microparticles were successfully prepared by the electrospray deposition method at one step. • The porous microparticles had high loading capacity and low density. • The microparticle showed a sustained release in the simulated gastric liquid. • The microparticles showed a slight cytotoxicity in vitro

Structural and surface morphological studies of long chain fatty acid thin films deposited by Langmuir-Blodgett technique

Energy Technology Data Exchange (ETDEWEB)

Das, Nayan Mani, E-mail: nayanmanidas3@gmail.com [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Roy, Dhrubojyoti [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Gupta, Mukul [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India); Gupta, P.S. [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India)

2012-12-15

In the present work we aim to study the structural and surface morphological characteristics of divalent cation (cadmium ion, Cd{sup 2+}) induced thin mono- to multilayer films of fatty acids such as arachidic acid and stearic acid prepared by the Langmuir-Blodgett (LB) technique. These ultra thin films of various numbers of layers were studied by X-ray diffraction (XRD), X-ray reflectivity (XRR) and Atomic Force Microscopy (AFM). In this specific Y-type deposition, it was found that as the individual layer thickness increases, the corresponding layer by layer interfacial electron density of the thin films decreases. Since the fatty acid chain tries to maintain its minimum value of cross-sectional area, tilting occurs with respect to its nearest neighbor. The tilt angle calculated for 9 layers of cadmium arachidate (CdA{sub 2}) and cadmium stearate (CdSt{sub 2}) are 18 Degree-Sign and 19.5 Degree-Sign , respectively. An asymmetric air gap of thickness {approx}3 A was also seen between the tail parts of 2 molecular chains. The RMS roughness and average height factors calculated through AFM studies show non-uniform surface morphology of both CdA{sub 2} and CdSt{sub 2}, although the calculated topographic variations were found to have more irregularity in case of CdSt{sub 2} than in case of CdA{sub 2}.

The effects of dietary boric acid and borax supplementation on lipid peroxidation, antioxidant activity, and DNA damage in rats.

Science.gov (United States)

Ince, Sinan; Kucukkurt, Ismail; Cigerci, Ibrahim Hakki; Fatih Fidan, A; Eryavuz, Abdullah

2010-07-01

The aims of this study were to clarify the effects of high dietary supplementation with boric acid and borax, called boron (B) compounds, on lipid peroxidation (LPO), antioxidant activity, some vitamin levels, and DNA damage in rats. Thirty Sprague Dawley male rats were divided into three equal groups: the animals in the first group (control) were fed with a standard rodent diet containing 6.4 mg B/kg, and the animals in the experimental group were fed with a standard rodent diet added with a supra-nutritional amount of boric acid and borax (100 mg B/kg) throughout the experimental period of 28 days. The B compounds decreased malondialdehyde (MDA), DNA damage, the protein carbonyl content (PCO) level in blood, and glutathione (GSH) concentration in the liver, Cu-Zn superoxide dismutase (SOD), and catalase (CAT) activity in the kidney. The B compounds increased GSH concentration in blood and the vitamin C level in plasma. Consequently, our results demonstrate that B supplementation (100 mg/kg) in diet decreases LPO, and enhances the antioxidant defense mechanism and vitamin status. There are no differences in oxidant/antioxidant balance and biochemical parameters except for serum vitamin A and liver GSH concentration, between the boron compounds used in this study. Crown Copyright 2010. Published by Elsevier GmbH. All rights reserved.

Intensification of ultraviolet-induced dermal damage by infrared radiation

International Nuclear Information System (INIS)

Kligman, L.H.

1982-01-01

To assess the role of IR in actinic damage to the dermis, albino guinea pigs were irradiated for 45 weeks with UV-B and UV-A, with and without IR. Control animals received IR only or no irradiation at all. Unirradiated dermis contains small amounts of elastic fibers in the upper dermis with greater depositions around follicles and sebaceous glands. After irradiation with UV, the fibers became more numerous, thicker, and more twisted; IR alone producd many fine, feathery fibers. The addition of IR to UV resulted in dense matlike elastic fiber depositions that exceeded what was observed with either irradiation alone. In combination or alone UV and IR radiation produced a large increase in ground substance, a finding also seen in actinically damaged human skin. Infrared radiation, in the physiologic range, though pleasant is not innocuous. (orig./MG) [de

Damaged-self recognition as a general strategy for injury detection

OpenAIRE

Heil, Martin

2012-01-01

Plants perceive endogenous molecules or their fragments as signals of danger when these appear at increased concentrations in the extracellular space, and they respond with increased endogenous levels of jasmonic acid. The wound hormone jasmonic acid represents a central player in the induced resistance of plants to herbivore feeding and infection by necrotrophic pathogens. This ‘damaged self recognition’ mechanism of plants exhibits astonishing similarities to the perception of ‘damage-assoc...

Low-fluorine Stockwork Molybdenite Deposits

Science.gov (United States)

Ludington, Steve; Hammarstrom, Jane; Piatak, Nadine M.

2009-01-01

Low-fluorine stockwork molybdenite deposits are closely related to porphyry copper deposits, being similar in their tectonic setting (continental volcanic arc) and the petrology (calc-alkaline) of associated igneous rock types. They are mainly restricted to the Cordillera of western Canada and the northwest United States, and their distribution elsewhere in the world may be limited. The deposits consist of stockwork bodies of molybdenite-bearing quartz veinlets that are present in and around the upper parts of intermediate to felsic intrusions. The deposits are relatively low grade (0.05 to 0.2 percent Mo), but relatively large, commonly >50 million tons. The source plutons for these deposits range from granodiorite to granite in composition; the deposits primarily form in continental margin subduction-related magmatic arcs, often concurrent with formation of nearby porphyry copper deposits. Oxidation of pyrite in unmined deposits or in tailings and waste rock during weathering can lead to development of acid-rock drainage and limonite-rich gossans. Waters associated with low-fluorine stockwork molybdenite deposits tend to be nearly neutral in pH; variable in concentrations of molybdenum (10,000 ug/L); below regulatory guidelines for copper, iron, lead, zinc, and mercury; and locally may exceed guidelines for arsenic, cadmium, and selenium.

The role of membrane cholesterol in determining bile acid cytotoxicity and cytoprotection of ursodeoxycholic acid

Science.gov (United States)

Zhou, Yong; Doyen, Rand; Lichtenberger, Lenard M.

2013-01-01

In cholestatic liver diseases, the ability of hydrophobic bile acids to damage membranes of hepatocytes/ductal cells contributes to their cytotoxicity. However, ursodeoxycholic acid (UDC), a hydrophilic bile acid, is used to treat cholestasis because it protects membranes. It has been well established that bile acids associate with and solubilize free cholesterol (CHOL) contained within the lumen of the gallbladder because of their structural similarities. However, there is a lack of understanding of how membrane CHOL, which is a well-established membrane stabilizing agent, is involved in cytotoxicity of hydrophobic bile acids and the cytoprotective effect of UDC. We utilized phospholipid liposomes to examine the ability of membrane CHOL to influence toxicity of individual bile acids, such as UDC and the highly toxic sodium deoxycholate (SDC), as well as the cytoprotective mechanism of UDC against SDC-induced cytotoxicity by measuring membrane permeation and intramembrane dipole potential. The kinetics of bile acid solubilization of phosphatidylcholine liposomes containing various levels of CHOL was also characterized. It was found that the presence of CHOL in membranes significantly reduced the ability of bile acids to damage synthetic membranes. UDC effectively prevented damaging effects of SDC on synthetic membranes only in the presence of membrane CHOL, while UDC enhances the damaging effects of SDC in the absence of CHOL. This further demonstrates that the cytoprotective effects of UDC depend upon the level of CHOL in the lipid membrane. Thus, changes in cell membrane composition, such as CHOL content, potentially influence the efficacy of UDC as the primary drug used to treat cholestasis. PMID:19150330

Hydrochloric acid poisoning

Science.gov (United States)

Hydrochloric acid is a clear, poisonous liquid. It is highly corrosive, which means it immediately causes severe damage, such ... poisoning due to swallowing or breathing in hydrochloric acid. This article is for information only. Do NOT ...

Deposition of acidifying compounds

International Nuclear Information System (INIS)

Fowler, D.; Cape, J.N.; Sutton, M.A.; Mourne, R.; Hargreaves, K.J.; Duyzer, J.H.; Gallagher, M.W.

1992-01-01

Inputs of acidifying compounds to terrestrial ecosystems include deposition of the gases NO 2 , NO, HNO 2 , HNO 3 , NH 3 and SO 2 and the ions NO 3- , NH 4+ , SO 4 2- and H + in precipitation, cloud droplets and particles. Recent research has identified particular ecosystems and regions in which terrestrial effects are closely linked with specific deposition processes. This review paper identifies areas in which important developments have occurred during the last five years and attempts to show which aspects of the subject are most important for policy makers. Amongst the conclusions drawn, the authors advise that current uncertainties in estimates of S and N inputs by dry deposition should be incorporated in critical load calculations, and that, in regions dominated by wet deposition, spatial resolution of total inputs should be improved to match the current scales of information on landscape sensitivity to acidic inputs. 44 refs., 9 figs

Acid Deposition Maps in Spain; Mapas de Deposito Acido en Espana

Energy Technology Data Exchange (ETDEWEB)

Artinano, B; Cabal, H; Garcia, C

1998-07-01

Animal and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To do this, updated databases with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5x5 Km{sup 2} grid which allow to assess the methodology used in Europe to obtain the maps of excedances over the critical loads of pollutants. (Author) 32 refs.

Acid Deposition Maps in Spain; Mapas de Deposito Acido en Espana

Energy Technology Data Exchange (ETDEWEB)

Artinano, B.; Cabal, H.; Garcia, C. [CIEMAT. Madrid (Spain)

1998-12-31

Annual and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To de this, updated database with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5 x 5 km``2 grid which allow to assess the methodology used in Europe to obtain the maps of excedance over the critical loads of pollutants. (Author) 32 refs.

Modelling regional response of lakewater chemistry to changes in acidic deposition: the MAGIC model applied to lake surveys in southernmost Norway 1974-1986-1995

Directory of Open Access Journals (Sweden)

B. J. Cosby

1998-01-01

Full Text Available Two methods for modelling regional responses of lake water quality to changes in acidic deposition in southernmost Norway were examined. Both methods are based upon the MAGIC model but differ in mode of regional application; one uses site-specific while the other uses Monte-Carlo methods for model calibration. The simulations of regional responses from both methods were compared with observed responses based on data from three lake surveys in southernmost Norway conducted in 1974, 1986 and 1995. The regional responses of the two modelling approaches were quite similar and agreed well with the observed regional distributions of lakewater chemistry variables. From 1974 to 1986 the observed data indicated that despite a decline of approximately 10% in sulphate (SO4 deposition, the mean acid neutralizing capacity (ANC of lakes in southernmost Norway declined by approximately 6 μeq l-1. Both modelling approaches simulated no change or a very small decline in mean ANC for that period. From 1986 to 1995 the observed data indicated that, in response to an approximate 40% decline in SO4 deposition, the mean ANC of lakes in southernmost Norway increased by 11-16 μeq l-1. The modelling approaches simulated increases of 9-10 μeq l-1 in mean ANC for the same period. Both simulations and observations indicate that > 65% of lakes in southernmost Norway were acidic in 1974 and 1995. Both simulation methods predict that >65% of the lakes in southernmost Norway will have positive ANC values within 10 years of reductions of SO4 deposition to 20% of 1974 levels. Of the two regionalization methods the site-specific method appears preferable, because whereas the Monte-Carlo method gives results for a region as a whole, the site-specific method also reveals patterns within the region. The maintenance of a one-to-one correspondence between simulated and observed systems means that simulation results can be mapped for a geographically explicit presentation of model

Acid rain publications by the U.S. Fish and Wildlife Service, 1979-1989

Science.gov (United States)

Villella, Rita F.

1989-01-01

Pollution of aquatic and terrestrial ecosystems has been a concern to society since the burning of fossil fuels began in the industrial revolution. In the past decade or so, this concern has been heightened by evidence that chemical transformation in the atmosphere of combustion by-products and subsequent long-range transport can cause environmental damage in remote areas. The extent of this damage and the rates of ecological recovery were largely unknown. "Acid rain" became the environmental issue of the 1980's. To address the increasing concerns of the public, in 1980 the Federal government initiated a 10-year interagency research program to develop information that could be used by the President and the Congress in making decisions for emission controls. The U.S. Fish and Wildlife Service has been an active participant in acid precipitation research. The Service provided support to a number of scientific conferences and forums, including the Action Seminar on Acid Precipitation held in Toronto, Canada, in 1979, an international symposium on Acidic Precipitation and Fishery Impacts in Northeastern North America in 1981, and a symposium on Acidic Precipitation and Atmospheric Deposition: A Western Perspective in 1982. These meetings as well as the growing involvement with the government's National Acidic Precipitation Assessment Program placed the Service in the lead in research on the biological effects of acidic deposition. Research projects have encompassed water chemistry, aquatic invertebrates, amphibians, fish, and waterfowl. Water quality surveys have been conducted to help determine the extent of acid precipitation effects in the northeast, Middle Atlantic, and Rocky Mountain regions. In addition to lake and stream studies, research in wetland and some terrestrial habitats has also been conducted. Specific projects have addressed important sport species such as brook trout (Salvelinus fontinalis), Atlantic salmon (Salmo salar), and striped bass (Morone

Reconnaissance map showing thickness of volcanic ash deposits in the greater Hilo area, Hawaii

Science.gov (United States)

Buchanan-Banks, Jane M.

1983-01-01

This study was undertaken to determine the thickness and distribution of volcanic ash deposits in the greater Hilo area, Hawaii, as a step toward evaluating their susceptibility to failure during earthquake shaking. On several occasions their instability has resulted in serious damage. For example, the 1868 earthquake (m=7+), following a prolonged rainy period, caused a debris flow of hillside ash deposits that killed 31 people in Wood Valley (Bringham, 1869). The 1973 Honomu earthquake (m=6.2) resulted in more damage from shaking to areas underlain by ash deposits in the older part of Hilo than in other areas, and soil slips in ash, as well as rockfalls, were common along the roads north of town (Nielsen and others, 1977). 

Cluster Deposition and Implantation on/in Graphite

DEFF Research Database (Denmark)

Popok, Vladimir

2013-01-01

is chosen for surface experiments because it is a good model material; it has an atomically smooth surface that makes it easy to resolve very small deposited clusters or damaged areas. Layered structure of graphite with strong covalent bonds in the graphene sheets and very week van der Waals interactions...

Effects of acid deposition on Dutch forest ecosystems

NARCIS (Netherlands)

Vries, de W.; Leeters, E.E.J.M.; Hendriks, C.M.A.

1995-01-01

Effects of elevated sulphur and nitrogen deposition on the solution chemistry of Dutch forest soils are mainly manifested by increased aluminium concentrations, associated with increased concentrations of sulphate and nitrate. Critical aluminium/base cation ratios are often exceeded below 20 cm soil

Protective Effect of Alpha Lipoic Acid on Rat Sciatic Nerve Ischemia Reperfusion Damage

Directory of Open Access Journals (Sweden)

Ozan Turamanlar

2015-06-01

Full Text Available Background: Alpha lipoic acid is a potent antioxidant that plays numerous roles in human health. This study examined the effect of ALA on rat sciatic nerve ischemia reperfusion damage. Aims: Protective effect of alpha lipoic acid (ALA on sciatic nerve following ischemia-reperfusion in rats was investigated by using light microscopy and biochemical methods. Provided that the protective effect of ALA on sciatic nerve is proven, we think the damage to the sciatic nerve that has already occurred or might occur in patients for various reasons maybe prevented or stopped by giving ALA in convenient doses. Study Design: Animal experiment. Methods: Forty-two adult male Sprague-Dawley rats (250-300 grams were used in this study. Rats were randomly divided into six groups including one control (Group 1, one sham (Group 2, two ischemia-reperfusion (Groups 3 and 4 and two treatment groups (Groups5 and 6. Doses of 60 and 100 mg/kg ALA were given (Group 5 and 6 intra peritoneally twice, 1 and 24 hours before the ischemia to each treatment group. Ischemia was carried out the abdominal aorta starting from the distal part of the renal vein for two hours followed by reperfusion for three hours. In immunohistochemical methods, fibronectin immunoreactivity was analyzed. For biochemical analyses, the tissues were taken in eppendorf microtubes and superoxide dismutase (SOD and glutathione peroxidase (GSHPx enzyme activities as well as malondialdehyde (MDA and nitricoxide (NO levels were measured. Results: Fibronectin was observed to have increased significantly in the ischemia group; on the other hand, it was observed to have decreased in parallel to the doses in the ALA groups. Biochemical studies showed that SOD and GSHPx declined with ischemia-reperfusion, but the activities of these enzymes were increased in the treatment groups in parallel with the dose. It was found that increased MDA levels with ischemia-reperfusion were decreased in parallel with ALA dose

Simulation of damage to tokamaks plasma facing components during intense abnormal power deposition

International Nuclear Information System (INIS)

Genco, F.; Hassanein, A.

2014-01-01

Highlights: • HEIGHTS-PIC a new technique based on particle in cell method to study disruptions events, ELMS and VDE is benchmarked in this paper with the use of the MK-200 experiments. • Disruptions simulations results for erosion and erosion rate are proposed showing good agreement with published experimental available data for such conditions. • Results are also compared with other published results produced by FOREV1/FOREV2 computer package and the original HEIGHTS computer package. • Accuracy of the simulations results is proposed with specific aim to address the use of number of super particles adopted versus computational time. - Abstract: Intense power deposition on plasma facing components (PFC) is expected in tokamaks during loss of confinement events such as disruptions, vertical displacement events (VDE), runaway electrons (RE), or during normal operating conditions such as edge-localized modes (ELM). These highly energetic events are damaging enough to hinder long term operation and may not be easily mitigated without loss of structural or functional performance of the PFC. Surface erosion, melted/ablated-vaporized material splashing, and material transport into the bulk plasma are reliability-threatening for the machine and system performance. A novel particle-in-cell (PIC) technique has been developed and integrated into the existing HEIGHTS package in order to obtain a global view of the plasma evolution upon energy impingement. This newly developed PIC technique is benchmarked against plasma gun experimental data, the original HEIGHTS computer package, and laser experiments. Benchmarking results are shown in this paper for various relevant reactor and experimental devices. The evolution of the plasma vapor cloud is followed temporally and results are explained and commented as a function of the computational time needed and the accuracy of the calculation

Laser-induced damage to thin film dielectric coatings

International Nuclear Information System (INIS)

Walker, T.W.

1980-01-01

The laser-induced damage thresholds of dielectric thin film coatings have been found to be more than an order of magnitude lower than the bulk material damage thresholds. Prior damage studies have been inconclusive in determining the damage mechanism which is operative in thin films. A program was conducted in which thin film damage thresholds were measured as a function of laser wavelength (1.06 μm, 0.53 μm, 0.35 μm and 0.26 μm), laser pulse length (5 and 15 nanoseconds), film materials and film thickness. The large matrix of data was compared to predictions given by avalanche ionization, multiphoton ionization and impurity theories of laser damage. When Mie absorption cross-sections and the exact thermal equations were included into the impurity theory excellent agreement with the data was found. The avalanche and multiphoton damage theories could not account for most parametric variations in the data. For example, the damage thresholds for most films increased as the film thickness decreased and only the impurity theory could account for this behavior. Other observed changes in damage threshold with changes in laser wavelength, pulse length and film material could only be adequately explained by the impurity theory. The conclusion which results from this study is that laser damage in thin film coatings results from absorbing impurities included during the deposition process

Molecular dynamics characterization of as-implanted damage in silicon

International Nuclear Information System (INIS)

Santos, Ivan; Marques, Luis A.; Pelaz, Lourdes; Lopez, Pedro; Aboy, Maria; Barbolla, Juan

2005-01-01

We have analyzed the as-implanted damage produced in silicon by B, Si and Ge ions using molecular dynamics (MD) simulations. Implantations were carried out at 50 K to avoid damage migration and annealing. In order to make a statistical study of the damage features, we have simulated hundreds of independent cascades for each ion for the same nuclear deposited energy. We have obtained that the average number of displaced atoms (DA) from perfect lattice positions and the size of defect clusters formed increases with ion mass. This dependence has not been obtained from equivalent binary collisions simulations. This indicates that multiple interactions play an important role in the generation of damage. Amorphous regions are directly formed during the collisional phase of the cascade of Ge and Si ions

Molecular dynamics characterization of as-implanted damage in silicon

Energy Technology Data Exchange (ETDEWEB)

Santos, Ivan [Dpto. de Electricidad y Electronica, Universidad de Valladolid, E.T.S.I. Telecomunicaciones, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)]. E-mail: ivasan@ele.uva.es; Marques, Luis A. [Dpto. de Electricidad y Electronica, Universidad de Valladolid, E.T.S.I. Telecomunicaciones, Campus Miguel Delibes s/n, 47011 Valladolid (Spain); Pelaz, Lourdes [Dpto. de Electricidad y Electronica, Universidad de Valladolid, E.T.S.I. Telecomunicaciones, Campus Miguel Delibes s/n, 47011 Valladolid (Spain); Lopez, Pedro [Dpto. de Electricidad y Electronica, Universidad de Valladolid, E.T.S.I. Telecomunicaciones, Campus Miguel Delibes s/n, 47011 Valladolid (Spain); Aboy, Maria [Dpto. de Electricidad y Electronica, Universidad de Valladolid, E.T.S.I. Telecomunicaciones, Campus Miguel Delibes s/n, 47011 Valladolid (Spain); Barbolla, Juan [Dpto. de Electricidad y Electronica, Universidad de Valladolid, E.T.S.I. Telecomunicaciones, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)

2005-12-05

We have analyzed the as-implanted damage produced in silicon by B, Si and Ge ions using molecular dynamics (MD) simulations. Implantations were carried out at 50 K to avoid damage migration and annealing. In order to make a statistical study of the damage features, we have simulated hundreds of independent cascades for each ion for the same nuclear deposited energy. We have obtained that the average number of displaced atoms (DA) from perfect lattice positions and the size of defect clusters formed increases with ion mass. This dependence has not been obtained from equivalent binary collisions simulations. This indicates that multiple interactions play an important role in the generation of damage. Amorphous regions are directly formed during the collisional phase of the cascade of Ge and Si ions.

Long-term intake of a high-protein diet increases liver triacylglycerol deposition pathways and hepatic signs of injury in rats.

Science.gov (United States)

Díaz-Rúa, Rubén; Keijer, Jaap; Palou, Andreu; van Schothorst, Evert M; Oliver, Paula

2017-08-01

Intake of high-protein (HP) diets has increased over the last years, mainly due to their popularity for body weight control. Liver is the main organ handling ingested macronutrients and it is associated with the beginning of different pathologies. We aimed to deepen our knowledge on molecular pathways affected by long-term intake of an HP diet. We performed a transcriptome analysis on liver of rats chronically fed with a casein-rich HP diet and analyzed molecular parameters related to liver injury. Chronic increase in the dietary protein/carbohydrate ratio up-regulated processes related with amino acid uptake/metabolism and lipid synthesis, promoting a molecular environment indicative of hepatic triacylglycerol (TG) deposition. Moreover, changes in expression of genes involved in acid-base maintenance and oxidative stress indicate alterations in the pH balance due to the high acid load of the diet, which has been linked to liver/health damage. Up-regulation of immune-related genes was also observed. In concordance with changes at gene expression level, we observed increased liver TG content and increased serum markers of hepatic injury/inflammation (aspartate transaminase, C-reactive protein and TNF-alpha). Moreover, the HP diet strongly increased hepatic mRNA and protein levels of HSP90, a marker of liver injury. Thus, we show for the first time that long-term consumption of an HP diet, resulting in a high acid load, results in a hepatic transcriptome signature reflecting increased TG deposition and increased signs of health risk (increased inflammation, alterations in the acid-base equilibrium and oxidative stress). Persistence of this altered metabolic status could have unhealthy consequences. Copyright © 2017 Elsevier Inc. All rights reserved.

Investigating the effects of dietary folic acid on sperm count, DNA damage and mutation in Balb/c mice

International Nuclear Information System (INIS)

Swayne, Breanne G.; Kawata, Alice; Behan, Nathalie A.; Williams, Andrew; Wade, Mike G.; MacFarlane, Amanda J.; Yauk, Carole L.

2012-01-01

To date, fewer than 50 mutagens have been studied for their ability to cause heritable mutations. The majority of those studied are classical mutagens like radiation and anti-cancer drugs. Very little is known about the dietary variables influencing germline mutation rates. Folate is essential for DNA synthesis and methylation and can impact chromatin structure. We therefore determined the effects of folic acid-deficient (0 mg/kg), control (2 mg/kg) and supplemented (6 mg/kg) diets in early development and during lactation or post-weaning on mutation rates and chromatin quality in sperm of adult male Balb/c mice. The sperm chromatin structure assay and mutation frequencies at expanded simple tandem repeats (ESTRs) were used to evaluate germline DNA integrity. Treatment of a subset of mice fed the control diet with the mutagen ethylnitrosourea (ENU) at 8 weeks of age was included as a positive control. ENU treated mice exhibited decreased cauda sperm counts, increased DNA fragmentation and increased ESTR mutation frequencies relative to non-ENU treated mice fed the control diet. Male mice weaned to the folic acid deficient diet had decreased cauda sperm numbers, increased DNA fragmentation index, and increased ESTR mutation frequency. Folic acid deficiency in early development did not lead to changes in sperm counts or chromatin integrity in adult mice. Folic acid supplementation in early development or post-weaning did not affect germ cell measures. Therefore, adequate folic acid intake in adulthood is important for preventing chromatin damage and mutation in the male germline. Folic acid supplementation at the level achieved in this study does not improve nor is it detrimental to male germline chromatin integrity.

Investigating the effects of dietary folic acid on sperm count, DNA damage and mutation in Balb/c mice

Energy Technology Data Exchange (ETDEWEB)

Swayne, Breanne G.; Kawata, Alice [Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, K1A 0K9 (Canada); Behan, Nathalie A. [Nutrition Research Division, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, K1A 0K9 (Canada); Williams, Andrew; Wade, Mike G. [Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, K1A 0K9 (Canada); MacFarlane, Amanda J. [Nutrition Research Division, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, K1A 0K9 (Canada); Yauk, Carole L., E-mail: carole.yauk@hc-sc.ga.ca [Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, K1A 0K9 (Canada)

2012-09-01

To date, fewer than 50 mutagens have been studied for their ability to cause heritable mutations. The majority of those studied are classical mutagens like radiation and anti-cancer drugs. Very little is known about the dietary variables influencing germline mutation rates. Folate is essential for DNA synthesis and methylation and can impact chromatin structure. We therefore determined the effects of folic acid-deficient (0 mg/kg), control (2 mg/kg) and supplemented (6 mg/kg) diets in early development and during lactation or post-weaning on mutation rates and chromatin quality in sperm of adult male Balb/c mice. The sperm chromatin structure assay and mutation frequencies at expanded simple tandem repeats (ESTRs) were used to evaluate germline DNA integrity. Treatment of a subset of mice fed the control diet with the mutagen ethylnitrosourea (ENU) at 8 weeks of age was included as a positive control. ENU treated mice exhibited decreased cauda sperm counts, increased DNA fragmentation and increased ESTR mutation frequencies relative to non-ENU treated mice fed the control diet. Male mice weaned to the folic acid deficient diet had decreased cauda sperm numbers, increased DNA fragmentation index, and increased ESTR mutation frequency. Folic acid deficiency in early development did not lead to changes in sperm counts or chromatin integrity in adult mice. Folic acid supplementation in early development or post-weaning did not affect germ cell measures. Therefore, adequate folic acid intake in adulthood is important for preventing chromatin damage and mutation in the male germline. Folic acid supplementation at the level achieved in this study does not improve nor is it detrimental to male germline chromatin integrity.

Defect control in room temperature deposited cadmium sulfide thin films by pulsed laser deposition

International Nuclear Information System (INIS)

Hernandez-Como, N.; Martinez-Landeros, V.; Mejia, I.; Aguirre-Tostado, F.S.; Nascimento, C.D.; Azevedo, G. de M; Krug, C.; Quevedo-Lopez, M.A.

2014-01-01

The control of defects in cadmium sulfide thin films and its impact on the resulting CdS optical and electrical characteristics are studied. Sulfur vacancies and cadmium interstitial concentrations in the CdS films are controlled using the ambient pressure during pulsed laser deposition. CdS film resistivities ranging from 10 −1 to 10 4 Ω-cm are achieved. Hall Effect measurements show that the carrier concentration ranges from 10 19 to 10 13 cm −3 and is responsible for the observed resistivity variation. Hall mobility varies from 2 to 12 cm 2 /V-s for the same pressure regime. Although the energy bandgap remains unaffected (∼ 2.42 eV), the optical transmittance is reduced due to the increase of defects in the CdS films. Rutherford back scattering spectroscopy shows the dependence of the CdS films stoichiometry with deposition pressure. The presence of CdS defects is attributed to more energetic species reaching the substrate, inducing surface damage in the CdS films during pulsed laser deposition. - Highlights: • CdS thin films deposited by pulsed laser deposition at room temperature. • The optical, electrical and structural properties were evaluated. • Carrier concentration ranged from 10 19 to 10 13 cm −3 . • The chemical composition was studied by Rutherford back scattering. • The density of sulfur vacancies and cadmium interstitial was varied

Ecological ranges for the pH and NO3 of syntaxa: a new basis for the estimation of critical loads for acid and nitrogen deposition

NARCIS (Netherlands)

Wamelink, G.W.W.; Goedhart, P.W.; Malinowska, A.H.; Frissel, J.Y.; Wegman, R.M.A.; Slim, P.A.; Dobben, van H.F.

2011-01-01

Question: Can the abiotic ranges of syntaxonomic units (associations) in terms of pH and nitrate concentration be estimated and then in principle be used to estimate critical loads for acid and nitrogen deposition? Location: Europe. Methods: Using splines, abiotic ranges of syntaxonomic units were

Use of soil-streamwater relationships to assess regional patterns of acidic deposition effects in the northeastern USA

Science.gov (United States)

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. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

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

International Nuclear Information System (INIS)

Mahgoub, Afaf; El-Medany, Azza; Mustafa, Ali; Arafah, Maha; Moursi, Mahmoud

2005-01-01

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 (TNFα) in colonic tissues. Inflammation following acetic acid instillation was characterized by oedema, diffuse inflammatory cell infiltration and necrosis. Increase in MPO, NOS and TNFα 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 TNFα 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

Preventing Ultraviolet Light-Induced Damage: The Benefits of Antioxidants

Science.gov (United States)

Yip, Cheng-Wai

2007-01-01

Extracts of fruit peels contain antioxidants that protect the bacterium "Escherichia coli" against damage induced by ultraviolet light. Antioxidants neutralise free radicals, thus preventing oxidative damage to cells and deoxyribonucleic acid. A high survival rate of UV-exposed cells was observed when grapefruit or grape peel extract was…

Effects of carotenoids on damage of biological lipids induced by gamma irradiation

International Nuclear Information System (INIS)

Saito, Takeshi; Fujii, Noriko

2014-01-01

Carotenoids are considered to be involved in the radioresistant mechanisms of radioresistant bacteria. In these bacterial cells, carotenoids are present in biological lipids, and therefore may be related to the radiation-induced damage of lipids. However, only limited data are available for the role of carotenoids in such damage. In this study, we irradiated an α-linolenic acid–benzene solution with gamma rays and analyzed the resulting oxidative degradation and peroxidation damage in the presence or absence of two typical carotenoids: β-carotene and astaxanthin. The analyses revealed that oxidative degradation and peroxidation of α-linolenic acid, as evaluated by the amount of malondialdehyde and conjugated diene formed, respectively, increased in a dose-dependent manner. Moreover, 8.5×10 −3 M β-carotene inhibited gamma radiation-induced oxidative degradation of α-linolenic acid, whereas 5.0×10 −5 and 5.0×10 −6 M β-carotene, and 5.0×10 −7 and 5.0×10 −8 M astaxanthin promoted degradation. In contrast, neither β-carotene nor astaxanthin affected peroxidation of α-linolenic acid. These results suggest that an optimum concentration of carotenoids in radioresistant bacteria protects biological lipid structures from radiation-induced damage. - Highlights: • Gamma radiation dose-dependently increases degradation levels of α-linolenic acid. • Gamma radiation dose-dependently increases peroxidation levels of α-linolenic acid. • An optimum concentration of carotenoids inhibits degradation of α-linolenic acid. • Relatively low concentrations of carotenoids promote degradation of α-linolenic acid. • Carotenoids do not affect the peroxidation level of α-linolenic acid

Mechanism research on coupling effect between dew point corrosion and ash deposition

International Nuclear Information System (INIS)

Wang, Yun-Gang; Zhao, Qin-Xin; Zhang, Zhi-Xiang; Zhang, Zhi-Chao; Tao, Wen-Quan

2013-01-01

In order to study the coupling mechanism between ash deposition and dew point corrosion, five kinds of tube materials frequently used as anti-dew point corrosion materials were selected as research objects. Dew point corrosion and ash deposition experiments were performed with a new type experimental device in a Chinese thermal power plant. The microstructures of the materials and the composition of ash deposition were analyzed by X-ray diffraction (XRD) and Energy Dispersive Spectrometer (EDS). The results showed that the ash deposition layer could be divided into non-condensation zone, the main condensation zone and the secondary condensation zone. The acid vapor condensed in the main condensation zone rather than directly on the tube wall surface. The dew point corrosion mainly is oxygen corrosion under the condition of the viscosity ash deposition, and the corrosion products are composed of the ash and acid reaction products in the outer layer, iron sulfate in the middle layer, and iron oxide in the inner layer. The innermost layer is the main corrosion layer. With the increase of the tube wall temperature, the ash deposition changes from the viscosity ash deposition to the dry loose ash deposition, the ash deposition rate decreases dramatically and dew point corrosion is alleviated efficiently. The sulfuric dew point corrosion resistance of the five test materials is as follows: 316L > ND > Corten>20G > 20 steel. -- Highlights: ► Dew point corrosion and ash deposition tests of five materials were performed. ► Acid vapor condensed in the ash deposit rather than directly on the tube surface. ► Dew point corrosion resistance is as follow: 316L > ND > Corten>20G > 20 steel. ► Dew point corrosion mainly is oxygen corrosion under viscosity ash deposition

Acid rain science and politics in Japan: a history of knowledge and action toward sustainability

Energy Technology Data Exchange (ETDEWEB)

Ken Wilkening

2004-07-01

This is a pioneering work in environmental and Asian history as well as an in-depth analysis of the influence of science on domestic and international environmental politics. The book is composed of the following chapters. Chapter 2 introduces the general set of concepts used to analyze the science-politics nexus. These concepts are employed in the remainder of the book to track and explain the relationship between science and policy related to the acid deposition problem in Japan. Chapter 3 discusses nature, culture, and the acid deposition problem in Japan. It begins with a brief introduction to the acid deposition problem in general. It continues with an overview of elements of Japan's natural environment and culture that are relevant to its acid deposition problems. This is followed by a quick sketch of the history of science in Japan, which in turn serves as a preamble for describing in the final section the environmental and acid deposition chronologies used to organize analysis of Japan's acid deposition history. The swath of history between 1868 and the present (circa 2000) is divided into five environmental eras and six acid deposition periods. Chapters 4-9 discuss in detail each of the six acid deposition periods. Chapter 10 synthesizes and summarizes what was learned in the process of analyzing Japan's acid deposition history, and draws lessons that might be applied to the challenge of creating sustainable societies in Japan, Asia, and the rest of the world. An appendix describes the present state of acid deposition science in Japan.

Water availability drives gas exchange and growth of trees in northeastern US, not elevated CO2 and reduced acid deposition.

Science.gov (United States)

Levesque, Mathieu; Andreu-Hayles, Laia; Pederson, Neil

2017-04-10

Dynamic global vegetation models (DGVM) exhibit high uncertainty about how climate change, elevated atmospheric CO 2 (atm. CO 2 ) concentration, and atmospheric pollutants will impact carbon sequestration in forested ecosystems. Although the individual roles of these environmental factors on tree growth are understood, analyses examining their simultaneous effects are lacking. We used tree-ring isotopic data and structural equation modeling to examine the concurrent and interacting effects of water availability, atm. CO 2 concentration, and SO 4 and nitrogen deposition on two broadleaf tree species in a temperate mesic forest in the northeastern US. Water availability was the strongest driver of gas exchange and tree growth. Wetter conditions since the 1980s have enhanced stomatal conductance, photosynthetic assimilation rates and, to a lesser extent, tree radial growth. Increased water availability seemingly overrides responses to reduced acid deposition, CO 2 fertilization, and nitrogen deposition. Our results indicate that water availability as a driver of ecosystem productivity in mesic temperate forests is not adequately represented in DGVMs, while CO 2 fertilization is likely overrepresented. This study emphasizes the importance to simultaneously consider interacting climatic and biogeochemical drivers when assessing forest responses to global environmental changes.

Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

Energy Technology Data Exchange (ETDEWEB)

Provine, J., E-mail: jprovine@stanford.edu; Schindler, Peter; Kim, Yongmin; Walch, Steve P.; Kim, Hyo Jin [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Kim, Ki-Hyun [Manufacturing Technology Center, Samsung Electronics, Suwon, Gyeonggi-Do (Korea, Republic of); Prinz, Fritz B. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

2016-06-15

The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiN{sub x}), particularly for use a low k dielectric spacer. One of the key material properties needed for SiN{sub x} 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 SiN{sub x} and evaluate the film’s WER in 100:1 dilutions of HF in H{sub 2}O. The remote plasma capability available in PEALD, enabled controlling the density of the SiN{sub x} 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 SiN{sub x} of 6.1 Å/min, which is similar to WER of SiN{sub x} from LPCVD reactions at 850 °C.

Boosting the performance of Pt electro-catalysts toward formic acid electro-oxidation by depositing sub-monolayer Au clusters

International Nuclear Information System (INIS)

Bi Xuanxuan; Wang Rongyue; Ding Yi

2011-01-01

Highlights: → Au decoration on Pt nanoparticles simultaneously increases the activity and stability. → Sub-monolayer Au decoration changes the reaction path and results in the activity improvement. → Increasing the Au coverage will increase the specific activity. → Proper Au coverage results in a maximum mass specific activity. - Abstract: CO poisoning is the main obstacle to the application of Pt nanoparticles as anode catalysts in direct formic acid fuel cells (DFAFCs). Significant types of Pt alloys have been investigated, which often demonstrate evidently improved catalytic performance governed by difference mechanisms. By using a well-known electrochemical technique of under potential deposition and in situ redox replacement, sub-monolayer Au clusters are deposited onto Pt nanoparticle surfaces in a highly controlled manner, generating a unique surface alloy structure. Under optimum conditions, the modified Pt nanoparticles can exhibit greatly enhanced specific activity (up to 23-fold increase) at potential of -0.2 V vs. MSE toward formic acid electro-oxidation (FAEO). Interestingly, the mass specific activity can also be improved by a factor of 2.3 at potential of -0.35 V vs. MSE although significant amount of surface Pt atoms are covered by the overlayer Au clusters. The much enhanced catalytic activity can be ascribed to a Pt surface ensemble effect, which induces change of the reaction path. Moreover, the sub-monolayer Au coating on the surface also contributes to the enhanced catalyst durability by inhibiting the Pt oxidation. These results show great potential to rationally design more active and stable nanocatalysts by modifying the Pt surface with otherwise inactive materials.

Dose effects on damage of thymidylic acid and its components irradiated by A N+ ion beam

International Nuclear Information System (INIS)

Shao Chunlin; Yu Zengliang

1996-08-01

Research into damage of DNA components is an important field in mechanism study to the low energy ion beam irradiation. It was found that the UV difference spectra of irradiated thymine (T) had two positive peaks caused by the changes of π electron conjugation of the pyrimidine ring, and that the residual activity of T sample irradiated by a N + ion beam was not influenced by treatments of acid and alkali as well as heat. In addition, the residual activities of irradiated thymidine (dTR) and thymidine 5'-phosphate (5'-dTMP) with and without treating of strong acid and strong alkali were also measured. With UV absorption spectrophotometry, the yield of T released from the irradiated samples of dTR and 5'-dTMP and the residual concentration of these target molecules were deduced, and it was found that the yield of T increased when the solution of the irradiated dTR sample was treated by heat but decreased when this solution was treated by acid and alkali for these treatments splitting T-S or T-S-P. On the other hand, the yield of inorganic phosphate released from the irradiated 5'-dTMP was investigated and found that it was increased by the treatment of alkali and that the increase degree was depended on the time scale of the treatment. Moreover, G(Pi) of the irradiated 5'-dTMP non-linearly decreased with increasing dose. (10 figs.)

STING-IRF3 Triggers Endothelial Inflammation in Response to Free Fatty Acid-Induced Mitochondrial Damage in Diet-Induced Obesity

Science.gov (United States)

Mao, Yun; Luo, Wei; Zhang, Lin; Wu, Weiwei; Yuan, Liangshuai; Xu, Hao; Song, Juhee; Fujiwara, Keigi; Abe, Jun-ichi; LeMaire, Scott A.; Wang, Xing Li; Shen, Ying. H.

2017-01-01

Objective Metabolic stress in obesity induces endothelial inflammation and activation, which initiates adipose tissue inflammation, insulin resistance, and cardiovascular diseases. However, the mechanisms underlying endothelial inflammation induction are not completely understood. Stimulator of interferon genes (STING) is an important molecule in immunity and inflammation. In the present study, we sought to determine the role of STING in palmitic acid (PA)-induced endothelial activation/inflammation. Approach and Results In cultured endothelial cells, PA treatment activated STING, as indicated by its perinuclear translocation and binding to interferon regulatory factor 3 (IRF3), leading to IRF3 phosphorylation and nuclear translocation. The activated IRF3 bound to the promoter of intercellular adhesion molecule 1 (ICAM-1) and induced ICAM-1 expression and monocyte–endothelial cell adhesion. When analyzing the upstream signaling, we found that PA activated STING by inducing mitochondrial damage. PA treatment caused mitochondrial damage and leakage of mitochondrial DNA (mtDNA) into the cytosol. Through the cytosolic DNA sensor cyclic GMP-AMP synthase (cGAS), the mitochondrial damage and leaked cytosolic mtDNA activated the STING-IRF3 pathway and increased ICAM-1 expression. In mice with diet-induced obesity, the STING-IRF3 pathway was activated in adipose tissue. However, STING deficiency (Stinggt/gt) partially prevented diet-induced adipose tissue inflammation, obesity, insulin resistance, and glucose intolerance. Conclusions The mitochondrial damage-cGAS-STING-IRF3 pathway is critically involved in metabolic stress-induced endothelial inflammation. STING may be a potential therapeutic target for preventing cardiovascular diseases and insulin resistance in obese individuals. PMID:28302626

Zinc-Nickel Codeposition in Sulfate Solution Combined Effect of Cadmium and Boric Acid

Directory of Open Access Journals (Sweden)

Y. Addi

2011-01-01

Full Text Available The combined effect of cadmium and boric acid on the electrodeposition of zinc-nickel from a sulfate has been investigated. The presence of cadmium ion decreases zinc in the deposit. In solution, cadmium inhibits the zinc ion deposition and suppresses it when deposition potential value is more negative than −1.2 V. Low concentration of CdSO4 reduces the anomalous nature of Zn-Ni deposit. Boric acid decreases current density and shifts potential discharge of nickel and hydrogen to more negative potential. The combination of boric acid and cadmium increases the percentage of nickel in the deposit. Boric acid and cadmium.

Protective function of complement against alcohol-induced rat liver damage.

Science.gov (United States)

Bykov, Igor L; Väkevä, Antti; Järveläinen, Harri A; Meri, Seppo; Lindros, Kai O

2004-11-01

The complement system can promote tissue damage or play a homeostatic role in the clearance and disposal of damaged tissue. We assessed the role of the terminal complement pathway in alcohol-induced liver damage in complement C6 (C6-/-) genetically deficient rats. C6-/- and corresponding C6+/+ rats were continuously exposed to ethanol by feeding ethanol-supplemented liquid diet for six weeks. Liver samples were analyzed for histopathology and complement component deposition by immunofluorescence microscopy. Prostaglandin E receptors and cytokine mRNA levels were analyzed by RT-PCR and plasma cytokines by ELISA. Deposition of complement components C1, C3, C8 and C9 was observed in C6+/+ rats, but not in C6-/- animals. The histopathological changes, the liver weight increase and the elevation of the plasma pro-/anti-inflammatory TNF-alpha/IL-10 ratio were, on the other hand, more marked in C6-/- rats. Furthermore, ethanol enhanced the hepatic mRNA expression of the prostaglandin E receptors EP2R and EP4R exclusively in the C6-/- rats. Our results indicate that a deficient terminal complement pathway predisposes to tissue injury and promotes a pro-inflammatory cytokine response. This suggests that an intact complement system has a protective function in the development of alcoholic liver damage.

Structural and Biochemical Changes in Salicylic-Acid-Treated Date Palm Roots Challenged with Fusarium oxysporum f. sp. albedinis

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Abdelhi Dihazi

2011-01-01

Full Text Available Histochemical and ultrastructural analyses were carried out to assess structural and biochemical changes in date palm roots pretreated with salicylic acid (SA then inoculated with Fusarium oxysporum f. sp. albedinis (Foa. Flavonoids, induced proteins, and peroxidase activity were revealed in root tissues of SA-treated plants after challenge by Foa. These reactions were closely associated with plant resistance to Foa. Host reactions induced after inoculation of SA-treated plants with Foa included the plugging of intercellular spaces, the deposition of electron-dense materials at the sites of pathogen penetration, and several damages to fungal cells. On the other hand, untreated inoculated plants showed marked cell wall degradation and total cytoplasm disorganization, indicating the protective effects provided by salicylic acid in treated plants.

Influence of standing-wave electric field pattern on the laser damage resistance of HfO sub 2 thin films

CERN Document Server

Protopapa, M L; De Tomasi, F; Di Giulio, M; Perrone, M R; Scaglione, S

2002-01-01

The standing-wave electric field pattern that forms inside an optical coating as a consequence of laser irradiation is one of the factors influencing the coating laser-induced damage threshold. The influence of the standing-wave electric field profile on the damage resistance to ultraviolet radiation of hafnium dioxide (HfO sub 2) thin films was investigated in this work. To this end, HfO sub 2 thin films of different thicknesses deposited by the electron beam evaporation technique at the same deposition conditions were analyzed. Laser damage thresholds of the samples were measured at 308 nm (XeCl laser) by the photoacoustic beam deflection technique and microscopic inspections. The dependence of the laser damage threshold on the standing-wave electric field pattern was analyzed.

Silicon Nitride Deposition for Flexible Organic Electronic Devices by VHF (162 MHz)-PECVD Using a Multi-Tile Push-Pull Plasma Source.

Science.gov (United States)

Kim, Ki Seok; Kim, Ki Hyun; Ji, You Jin; Park, Jin Woo; Shin, Jae Hee; Ellingboe, Albert Rogers; Yeom, Geun Young

2017-10-19

Depositing a barrier film for moisture protection without damage at a low temperature is one of the most important steps for organic-based electronic devices. In this study, the authors investigated depositing thin, high-quality SiN x film on organic-based electronic devices, specifically, very high-frequency (162 MHz) plasma-enhanced chemical vapor deposition (VHF-PECVD) using a multi-tile push-pull plasma source with a gas mixture of NH 3 /SiH 4 at a low temperature of 80 °C. The thin deposited SiN x film exhibited excellent properties in the stoichiometry, chemical bonding, stress, and step coverage. Thin film quality and plasma damage were investigated by the water vapor transmission rate (WVTR) and by electrical characteristics of organic light-emitting diode (OLED) devices deposited with SiN x , respectively. The thin deposited SiN x film exhibited a low WVTR of 4.39 × 10 -4  g (m 2 · day) -1 for a single thin (430 nm thick) film SiN x and the electrical characteristics of OLED devices before and after the thin SiN x film deposition on the devices did not change, which indicated no electrical damage during the deposition of SiN x on the OLED device.

Effect of astaxanthin in combination with alpha-tocopherol or ascorbic acid against oxidative damage in diabetic ODS rats.

Science.gov (United States)

Nakano, Masako; Onodera, Aya; Saito, Emi; Tanabe, Miyako; Yajima, Kazue; Takahashi, Jiro; Nguyen, Van Chuyen

2008-08-01

The present study was performed to investigate the effect of astaxanthin in combination with other antioxidants against oxidative damage in streptozotocin (STZ)-induced diabetic Osteogenic Disorder Shionogi (ODS) rats. Diabetic-ODS rats were divided into five groups: control, astaxanthin, ascorbic acid, alpha-tocopherol, and tocotrienol. Each of the four experimental groups was administered a diet containing astaxanthin (0.1 g/kg), in combination with ascorbic acid (3.0 g/kg), alpha-tocopherol (0.1 g/kg), or tocotrienol (0.1 g/kg) for 20 wk. The effects of astaxanthin with other antioxidants on lipid peroxidation, urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) excretion, serum creatinine (Cr) level, creatinine clearance (Ccr), and urinary protein content were assessed. The serum lipid peroxide levels and chemiluminescent (CL) intensity in the liver of the alpha-tocopherol and tocotrienol groups were significantly reduced in comparison to that of the control group. In the alpha-tocopherol group, urinary 8-OHdG excretion, serum Cr level, Ccr, urinary albumin excretion, and urinary protein concentration were significantly decreased as compared with those in the control group. Additionally, the CL intensity in the kidney of the alpha-tocopherol group was significantly lower, but that of the ascorbic acid group was significantly higher than that in the control group. These results indicate that dietary astaxanthin in combination with alpha-tocopherol has an inhibitory effect on oxidative stress. On the other hand, our study suggests that excessive ascorbic acid intake increases lipid peroxidation in diabetic rats.

Pollution Damage and Protection of Asian Hair

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Xin Qu

2018-02-01

Full Text Available Cigarette smoke was used to simulate a polluted environment and an experiment was performed to reveal how virgin and bleached hair are damaged by a polluted environment. The dry/wet combability, surface contact angle, tryptophan content, and cuticle morphology of the smoke exposed hair were evaluated, and compared to unexposed virgin hair. The results showed that pollution exposure can cause significant chemical damage to hair. In particular, virgin hair exposure to pollution can cause damage to the hair cuticles (higher wet/dry combing, protein degradation, and a more hydrophilic hair surface. The experiment also demonstrated that the styling polymer, polyimide-1 (isobutylene/dimethyl amino propyl maleimide/ethoxylated maleimide/maleic acid copolymer, can provide effective protection against such hair damage.

Spectroellipsometric detection of silicon substrate damage caused by radiofrequency sputtering of niobium oxide

Science.gov (United States)

Lohner, Tivadar; Serényi, Miklós; Szilágyi, Edit; Zolnai, Zsolt; Czigány, Zsolt; Khánh, Nguyen Quoc; Petrik, Péter; Fried, Miklós

2017-11-01

Substrate surface damage induced by deposition of metal atoms by radiofrequency (rf) sputtering or ion beam sputtering onto single-crystalline silicon (c-Si) surface has been characterized earlier by electrical measurements. The question arises whether it is possible to characterize surface damage using spectroscopic ellipsometry (SE). In our experiments niobium oxide layers were deposited by rf sputtering on c-Si substrates in gas mixture of oxygen and argon. Multiple angle of incidence spectroscopic ellipsometry measurements were performed, a four-layer optical model (surface roughness layer, niobium oxide layer, native silicon oxide layer and ion implantation-amorphized silicon [i-a-Si] layer on a c-Si substrate) was created in order to evaluate the spectra. The evaluations yielded thicknesses of several nm for the i-a-Si layer. Better agreement could be achieved between the measured and the generated spectra by inserting a mixed layer (with components of c-Si and i-a-Si applying the effective medium approximation) between the silicon oxide layer and the c-Si substrate. High depth resolution Rutherford backscattering (RBS) measurements were performed to investigate the interface disorder between the deposited niobium oxide layer and the c-Si substrate. Atomic resolution cross-sectional transmission electron microscopy investigation was applied to visualize the details of the damaged subsurface region of the substrate.

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

Science.gov (United States)

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

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

Directory of Open Access Journals (Sweden)

Gaëtan Gruel

Full Text Available 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

Endoplasmic reticulum stress involved in high-fat diet and palmitic acid-induced vascular damages and fenofibrate intervention

Energy Technology Data Exchange (ETDEWEB)

Lu, Yunxia, E-mail: wwwdluyx@sina.com [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); The Comprehensive Laboratory, Anhui Medical University, Hefei, Anhui 230032 (China); Cheng, Jingjing [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Chen, Li [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Department of Medical Laboratory, Anhui Provincial Hospital, Hefei, Anhui 230001 (China); Li, Chaofei; Chen, Guanjun [Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui 230032 (China); Gui, Li [The Comprehensive Laboratory, Anhui Medical University, Hefei, Anhui 230032 (China); Shen, Bing [Department of Physiology, Anhui Medical University, Hefei, Anhui 230032 (China); Zhang, Qiu [Department of Endocrinology, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022 (China)

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

Molecular weight evaluation of poly-dimethylsiloxane on solid surfaces using silver deposition/TOF-SIMS

Science.gov (United States)

Inoue, Masae; Murase, Atsushi

2004-06-01

Molecular ions include information about end groups, functional groups and molecular weight. A method for directly detecting this in the high-mass region of the spectrum (>1000 amu) from poly-dimethylsiloxane (PDMS) on a solid surface was investigated. It was found that a TOF-SIMS analysis of silver-deposited surfaces (silver deposition/TOF-SIMS) is useful for this purpose. Two methods for silver deposition, the diode sputtering method and the vacuum evaporation coating method, were tried. The former required the sample to be cooled so as to prevent the damage of the sample surface due to thermal oxidation; the latter caused no damage to sample surfaces at room temperature. Using silver deposition/TOF-SIMS analysis, silver-cationized quasi-molecular ions were clearly detected from PDMS on solid surfaces and their images were observed without the interference of deposited silver. By applying to the analysis of paint defects, etc., it was confirmed that this technique is useful to analyze practical industrial materials. Silver-cationized ions were detected not only from PDMS, but also from other organic materials, such as some kinds of lubricant additives and fluorine oils on solid surfaces. Therefore, silver deposition/TOF-SIMS was proved to be useful for the analysis of thin substances on solid surfaces.

Laser detritiation and co-deposited layer characterisation for future ITER Installation

International Nuclear Information System (INIS)

Semerok, Alexandre; Brygo, Francois; Fomichev, Sergey V.; Champonnois, Francois; Weulersse, Jean-Marc; Thro, Pierre-Yves; Fichet, Pascal; Grisolia, Christian

2006-01-01

The experimental equipment in combination with pulsed Nd-YAG lasers was developed and applied to investigate co-deposited layer characterisation and ablation. Heating and ablation regimes were distinguished by ablation threshold fluence that was determined experimentally for graphite samples from TexTor (Germany) and TORE SUPRA (France) tokamaks. With 100 ns pulses, the ablation threshold for graphite substrate (2.5±0.5 J/cm 2 ) was much higher than the one for co-deposited layer (0.4±0.1 J cm -2 ). These threshold features are very promising to ensure self-controlled laser cleaning without substrate surface damage. The obtained optimal conditions (laser fluence F=1-2 J/cm 2 , 10-20 kHz repetition rate) were applied for co-deposited layer cleaning. The TexTor 50 μm thickness layer was almost completely removed after a single scanning without any damage of the graphite substrate. Cleaning rate of 0.2 m 2 /hour was demonstrated experimentally for 20 W mean laser power. A theoretical model of a complex surface heating (graphite or metal with a co-deposited layer) was developed to explain the experimental results and to obtain laser cleaning optimisation. A good agreement of the theoretical data with the experimental results was obtained. The studies on LIBS method for co-deposited layer characterisation have determined the analytical spectral lines for hydrogen, carbon, and other impurities (B, Fe, Si, and Cu) in TexTor graphite tile. The obtained results should be regarded optimistic for co-deposited layers characterisation by LIBS method. The development of certain laser methods and their application for in-situ detritiation and co-deposited layer characterisation are presented and discussed. (authors)

Self-Healing Characteristics of Damaged Rock Salt under Different Healing Conditions

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Lin Li

2013-08-01

Full Text Available Salt deposits are commonly regarded as ideal hosts for geologic energy reservoirs. Underground cavern construction-induced damage in salt is reduced by self-healing. Thus, studying the influencing factors on such healing processes is important. This research uses ultrasonic technology to monitor the longitudinal wave velocity variations of stress-damaged rock salts during self-recovery experiments under different recovery conditions. The influences of stress-induced initial damage, temperature, humidity, and oil on the self-recovery of damaged rock salts are analyzed. The wave velocity values of the damaged rock salts increase rapidly during the first 200 h of recovery, and the values gradually increase toward stabilization after 600 h. The recovery of damaged rock salts is subjected to higher initial damage stress. Water is important in damage recovery. The increase in temperature improves damage recovery when water is abundant, but hinders recovery when water evaporates. The presence of residual hydraulic oil blocks the inter-granular role of water and restrains the recovery under triaxial compression. The results indicate that rock salt damage recovery is related to the damage degree, pore pressure, temperature, humidity, and presence of oil due to the sealing integrity of the jacket material.

Defect control in room temperature deposited cadmium sulfide thin films by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Hernandez-Como, N. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Martinez-Landeros, V. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Centro de Investigación en Materiales Avanzados, Monterrey, Nuevo Leon, 66600, México (Mexico); Mejia, I. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Aguirre-Tostado, F.S. [Centro de Investigación en Materiales Avanzados, Monterrey, Nuevo Leon, 66600, México (Mexico); Nascimento, C.D.; Azevedo, G. de M; Krug, C. [Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91509-900 (Brazil); Quevedo-Lopez, M.A., E-mail: mquevedo@utdallas.edu [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States)

2014-01-01

The control of defects in cadmium sulfide thin films and its impact on the resulting CdS optical and electrical characteristics are studied. Sulfur vacancies and cadmium interstitial concentrations in the CdS films are controlled using the ambient pressure during pulsed laser deposition. CdS film resistivities ranging from 10{sup −1} to 10{sup 4} Ω-cm are achieved. Hall Effect measurements show that the carrier concentration ranges from 10{sup 19} to 10{sup 13} cm{sup −3} and is responsible for the observed resistivity variation. Hall mobility varies from 2 to 12 cm{sup 2}/V-s for the same pressure regime. Although the energy bandgap remains unaffected (∼ 2.42 eV), the optical transmittance is reduced due to the increase of defects in the CdS films. Rutherford back scattering spectroscopy shows the dependence of the CdS films stoichiometry with deposition pressure. The presence of CdS defects is attributed to more energetic species reaching the substrate, inducing surface damage in the CdS films during pulsed laser deposition. - Highlights: • CdS thin films deposited by pulsed laser deposition at room temperature. • The optical, electrical and structural properties were evaluated. • Carrier concentration ranged from 10{sup 19} to 10{sup 13} cm{sup −3}. • The chemical composition was studied by Rutherford back scattering. • The density of sulfur vacancies and cadmium interstitial was varied.