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Sample records for chemically modified amazon

  1. AMAZON RAINFOREST COSMETICS: CHEMICAL APPROACH FOR QUALITY CONTROL

    OpenAIRE

    Mariko Funasaki; Hileia dos Santos Barroso; Valdelira Lia Araújo Fernandes; Ingrid Sabino Menezes

    2016-01-01

    The market for natural cosmetics featuring ingredients derived from Amazon natural resources is growing worldwide. However, there is neither enough scientific basis nor quality control of these ingredients. This paper is an account of the chemical constituents and their biological activities of fourteen Amazonian species used in cosmetic industry, including açaí (Euterpe oleracea), andiroba (Carapa guianensis), bacuri (Platonia insignis), Brazil nut (Bertholletia excelsa), buriti (Mauritia vi...

  2. AMAZON RAINFOREST COSMETICS: CHEMICAL APPROACH FOR QUALITY CONTROL

    Directory of Open Access Journals (Sweden)

    Mariko Funasaki

    2016-02-01

    Full Text Available The market for natural cosmetics featuring ingredients derived from Amazon natural resources is growing worldwide. However, there is neither enough scientific basis nor quality control of these ingredients. This paper is an account of the chemical constituents and their biological activities of fourteen Amazonian species used in cosmetic industry, including açaí (Euterpe oleracea, andiroba (Carapa guianensis, bacuri (Platonia insignis, Brazil nut (Bertholletia excelsa, buriti (Mauritia vinifera or M. flexuosa, cumaru (Dipteryx odorata, cupuaçu (Theobroma grandiflorum, guarana (Paullinia cupana, mulateiro (Calycophyllum spruceanum, murumuru (Astrocaryum murumuru, patawa (Oenocarpus bataua or Jessenia bataua, pracaxi (Pentaclethra macroloba, rosewood (Aniba rosaeodora, and ucuuba (Virola sebifera. Based on the reviewed articles, we selected chemical markers for the quality control purpose and evaluated analytical methods. Even though chromatographic and spectroscopic methods are major analytical techniques in the studies of these species, molecular approaches will also be important as used in food and medicine traceability. Only a little phytochemical study is available about most of the Amazonian species and some species such as açaí and andiroba have many reports on chemical constituents, but studies on biological activities of isolated compounds and sampling with geographical variation are limited.

  3. Synthesis of chemically modified DNA.

    Science.gov (United States)

    Shivalingam, Arun; Brown, Tom

    2016-06-15

    Naturally occurring DNA is encoded by the four nucleobases adenine, cytosine, guanine and thymine. Yet minor chemical modifications to these bases, such as methylation, can significantly alter DNA function, and more drastic changes, such as replacement with unnatural base pairs, could expand its function. In order to realize the full potential of DNA in therapeutic and synthetic biology applications, our ability to 'write' long modified DNA in a controlled manner must be improved. This review highlights methods currently used for the synthesis of moderately long chemically modified nucleic acids (up to 1000 bp), their limitations and areas for future expansion. PMID:27284032

  4. Observations about chemical composition of aerosols in the Brazilian Amazon region - Case study: Biomass burning in the subequatorial Amazon region

    Science.gov (United States)

    Gioda, A.; Monteiro, I. L.; Almeida, A. C.; Hacon, S. S.; Dallacort, R.; Ignotti, E.; Godoy, J. M.; Loureiro, A. L.; Morais, F.; Artaxo, P.

    2012-04-01

    The study was carried out in two cities in the Brazilian Amazon region, Tangará da Serra (14 ° 37'10 "S, 57 ° 29'09" W, 427 m asl), located in a transition area between the Amazon biome and the Cerrado and has the characteristics of urban area in Amazon region; and Alta Floresta (9 ° 52 '32 "S, 56 ° 5' 10" W, 283 m asl) situated in the extreme north of the state of Mato Grosso (MT), both in the subequatorial Amazon region. Tangara da Serra has the largest production of sugar cane in the subequatorial Amazon region. They are located 800 km from each other. These two regions are inserted in a region with typical cycles of drought and rain that alter air pollution levels, and lies in the dispersion path of the pollution plume resulting from burnings in the Brazilian Amazon and pollution emanating from neighboring countries. Both cities have wet tropical climate with two well defined seasons: rainy summer (November to May) and dry winter (June to October). During the dry winter, biomass burnings are frequent in these regions. In 2008, the Department of the Environment has banned fires in the period from July 15 to September 15 throughout the State. In this study chemical characterization was performed for approximately 100 aerosol samples collected in each site during 2008. Fine and coarse aerosol samples collected in SFUs were analyzed by ion chromatography for determination of cations (Na+, K+, NH3+, Ca2+ and Mg2+), anions (SO42-, Cl- and NO3-) and organic acids (acetate and formiate) and also measures of black carbon (BC) (Aethalometer). The results showed that for both sites the average concentrations were quite similar for PM2.5 (16 µg/m3), PM10 (11 and 13 µg/m3) and black carbon (1.4 µg/m3 for PM2.5 and 1.6 µg/m3 for PM10). Sulfate was the predominant species in fine (45%) and coarse (26%) particles in both sites. The sulfate concentrations ranged from 0.01-1.92 µg/m3 in PM2.5 and 0.01-1.66 µg/m3 in PM10 in Tangará da Serra and 0.01-2.93 µg/m3 in PM2

  5. GoAmazon 2014/15 Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, JN [Univ. of California, Irvine, CA (United States)

    2016-04-01

    The Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS) deployment to the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility T3 site in Manacapuru, Brazil, was motivated by two main scientific objectives of the Green Ocean Amazon (GoAmazon) 2014/15 field campaign. 1) Study the interactions between anthropogenic and biogenic emissions by determining important molecular species in ambient nanoparticles. To address this, TDCIMS data will be combined with coincident measurements such as gas-phase sulfuric acid to determine the contribution of sulfuric acid condensation to nucleation and growth. We can then compare that result to TDCIMS-derived nanoparticle composition to determine the fraction of growth that can be attributed to the uptake of organic compounds. The molecular composition of sampled particles will also be used to attribute specific chemical species and mechanisms to growth, such as the condensation of low-volatility species or the oligomerization of α-dicarbonyl compounds. 2) Determine the source of new ambient nanoparticles in the Amazon. The hypothesis prior to measurements was that potassium salts formed from the evaporation of primary particles emitted by fungal spores can provide a unique and important pathway for new particle production in the Amazon basin. To explore this hypothesis, the TDCIMS recorded the mass spectra of sampled ambient particles using a protonated water cluster Chemical Ionization Mass Spectrometer (CIMS). Laboratory tests performed using potassium salts show that the TDCIMS can detect potassium with high sensitivity with this technique.

  6. Chemical and physical properties of Amazon forest soils in relation to their genesis

    Directory of Open Access Journals (Sweden)

    C. A. Quesada

    2009-04-01

    Full Text Available Soil samples were collected in six South American countries in a total of 71 different 1 ha forest plots across the Amazon Basin as part of the RAINFOR project. They were analysed for total and exchangeable cations, C, N, pH with various P fractions also determined. Physical properties were also examined and an index of soil physical quality proposed. A diverse range of soils was found. For the western areas near the Andean cordillera and the southern and northern fringes, soils tend to be distributed among the lower pedogenetic levels, while the central and eastern areas of Amazonia have more intensely weathered soils. This gives rise to a large variation of soil chemical and physical properties across the Basin, with soil properties varying predictably along a gradient of pedogenic development. Nutrient pools generally increased slightly in concentration from the youngest to the intermediate aged soils after which a gradual decline was observed with the lowest values found in the most weathered soils. Soil physical properties were strongly correlated with soil fertility, with favourable physical properties occurring in highly weathered and nutrient depleted soils and with the least weathered, more fertile soils having higher incidence of limiting physical properties. Soil phosphorus concentrations varied markedly in accordance with weathering extent and appear to exert an important influence on the nitrogen cycle of Amazon forest soils.

  7. Long-term Chemical Characterization of Submicron Aerosol Particles in the Amazon Forest - ATTO Station

    Science.gov (United States)

    Carbone, S.; Brito, J.; Rizzo, L. V.; Holanda, B. A.; Cirino, G. G.; Saturno, J.; Krüger, M. L.; Pöhlker, C.; Ng, N. L.; Xu, L.; Andreae, M. O.; Artaxo, P.

    2015-12-01

    The study of the chemical composition of aerosol particles in the Amazon forest represents a step forward to understand the strong coupling between the atmosphere and the forest. For this reason submicron aerosol particles were investigated in the Amazon forest, where biogenic and anthropogenic aerosol particles coexist at the different seasons (wet/dry). The measurements were performed at the ATTO station, which is located about 150 km northeast of Manaus. At ATTO station the Aerosol chemical speciation monitor (ACSM, Aerodyne) and the Multiangle absorption photometer (MAAP, Thermo 5012) have been operated continuously from March 2014 to July 2015. In this study, long-term measurements (near-real-time, ~30 minutes) of PM1 chemical composition were investigated for the first time in this environment.The wet season presented lower concentrations than the dry season (~5 times). In terms of chemical composition, both seasons were dominated by organics (75 and 63%) followed by sulfate (11 and 13%). Nitrate presented different ratio values between the mass-to-charges 30 to 46 (main nitrate fragments) suggesting the presence of nitrate as inorganic and organic nitrate during both seasons. The results indicated that about 75% of the nitrate signal was from organic nitrate during the dry season. In addition, several episodes with elevated amount of chloride, likely in the form of sea-salt from the Atlantic Ocean, were observed during the wet season. During those episodes, chloride comprised up to 7% of the PM1. During the dry season, chloride was also observed; however, with different volatility, which suggested that Chloride was present in different form and source. Moreover, the constant presence of sulfate and BC during the wet season might be related to biomass burning emissions from Africa. BC concentration was 2.5 times higher during the dry season. Further characterization of the organic fraction was accomplished with the positive matrix factorization (PMF), which

  8. Quality of chemically modified hemp fibers.

    Science.gov (United States)

    Kostic, Mirjana; Pejic, Biljana; Skundric, Petar

    2008-01-01

    Hemp fibers are very interesting natural material for textile and technical applications now. Applying hemp fibers to the apparel sector requires improved quality fibers. In this paper, hemp fibers were modified with sodium hydroxide solutions (5% and 18% w/v), at room and boiling temperature, for different periods of time, and both under tension and slack, in order to partially extract noncellulosic substances, and separate the fiber bundles. The quality of hemp fibers was characterised by determining their chemical composition, fineness, mechanical and sorption properties. The modified hemp fibers were finer, with lower content of lignin, increased flexibility, and in some cases tensile properties were improved. An original method for evaluation of tensile properties of hemp fibers was developed.

  9. Antitumor activity of chemical modified natural compounds

    Directory of Open Access Journals (Sweden)

    Marilda Meirelles de Oliveira

    1991-01-01

    Full Text Available Search of new activity substances starting from chemotherapeutic agents, continously appears in international literature. Perhaps this search has been done more frequently in the field of anti-tumor chemotherapy on account of the unsuccess in saving advanced stage patients. The new point in this matter during the last decade was computer aid in planning more rational drugs. In near future "the accessibility of supercomputers and emergence of computer net systems, willopen new avenues to rational drug design" (Portoghese, P. S. J. Med. Chem. 1989, 32, 1. Unknown pharmacological active compounds synthetized by plants can be found even without this eletronic devices, as tradicional medicine has pointed out in many contries, and give rise to a new drug. These compounds used as found in nature or after chemical modifications have produced successful experimental medicaments as FAA, "flavone acetic acid" with good results as inibitors of slow growing animal tumors currently in preclinical evaluation for human treatment. In this lecture some international contributions in the field of chemical modified compounds as antineoplasic drugs will be examined, particularly those done by Brazilian researches.

  10. Biomass burning aerosol over the Amazon during SAMBBA: impact of chemical composition on radiative properties

    Science.gov (United States)

    Morgan, William; Allan, James; Flynn, Michael; Darbyshire, Eoghan; Hodgson, Amy; Liu, Dantong; O'shea, Sebastian; Bauguitte, Stephane; Szpek, Kate; Langridge, Justin; Johnson, Ben; Haywood, Jim; Longo, Karla; Artaxo, Paulo; Coe, Hugh

    2014-05-01

    Biomass burning represents one of the largest sources of particulate matter to the atmosphere, resulting in a significant perturbation to the Earth's radiative balance coupled with serious impacts on public health. Globally, biomass burning aerosols are thought to exert a small warming effect but with the uncertainty being 4 times greater than the central estimate. On regional scales, the impact is substantially greater, particularly in areas such as the Amazon Basin where large, intense and frequent burning occurs on an annual basis for several months. Absorption by atmospheric aerosols is underestimated by models over South America, which points to significant uncertainties relating to Black Carbon (BC) aerosol properties. Initial results from the South American Biomass Burning Analysis (SAMBBA) field experiment, which took place during September and October 2012 over Brazil on-board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft, are presented here. Aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and a DMT Single Particle Soot Photometer (SP2). The physical, chemical and optical properties of the aerosols across the region will be characterized in order to establish the impact of biomass burning on regional air quality, weather and climate. The aircraft sampled a range of conditions including sampling of pristine Rainforest, fresh biomass burning plumes, regional haze and elevated biomass burning layers within the free troposphere. The aircraft sampled biomass burning aerosol across the southern Amazon in the states of Rondonia and Mato Grosso, as well as in a Cerrado (Savannah-like) region in Tocantins state. This presented a range of fire conditions, both in terms of their number, intensity, vegetation-type and their combustion efficiencies. Near-source sampling of fires in Rainforest environments suggested that smouldering combustion dominated, while flaming combustion dominated

  11. Chemically modified flexible strips as electrochemical biosensors.

    Science.gov (United States)

    Thota, Raju; Ganesh, V

    2014-09-21

    A flexible and disposable strip sensor for non-enzymatic glucose detection is demonstrated in this work. The strips are prepared by using chemical modification processes followed by a simple electroless deposition of copper. Essentially, polyester overhead projector (OHP) transparent films are modified with a monolayer of 3-aminopropyltrimethoxysilane (APTMS) and polyaniline (PANI) conducting polymer. Later, nanostructured copper is deposited onto this modified film. Scanning electron microscope (SEM) and X-ray diffraction (XRD) studies are used for the structural, morphological and crystallinity characterization of the modified films. Electrochemical techniques, namely cyclic voltammetry (CV) and chronoamperometry (CA), are employed for the non-enzymatic detection of glucose. These studies clearly reveal the formation of homogeneous, close-packed spherical Cu particles converged into uniform film that exhibits a good catalytic activity towards the oxidation of glucose. The Cu/PANI/APTMS/OHP sensor displays a remarkable enhancement in the oxidation current density, a very high sensitivity value of 2.8456 mA cm(-2) per mM, and a linear concentration range from 100 μM to 6.5 mM associated with glucose detection. Detection limit is estimated to be 5 μM and the response time of the sensor is determined to be less than 5 s. For comparison, similar studies are performed without PANI, namely Cu/APTMS/OHP films for glucose detection. In this case, a sensitivity value of 2.4457 mA cm(-2) per mM and a linear concentration range of 100 μM-3 mM are estimated. The higher performance characteristics observed in the case of Cu/PANI/APTMS/OHP are attributed to the synergistic effects of the conducting polymer acting as an electron facilitator and the nanostructured Cu films. These disposable, flexible and low-cost strip sensors have also been applied to the detection of glucose in clinical blood serum samples and the results obtained agree very well with the actual glucose

  12. Chemical and carbon isotope composition of Varzeas sediments and its interactions with some Amazon basin rivers

    International Nuclear Information System (INIS)

    Varzea sediment samples were collected on the banks of Amazon rivers and in the most important tributaires. The samples were taken in three different river stages. The major cations, pH, total nitrogen, total phosphorus, carbon and δ13C values were determined. The concentration of major basic cations - Ca,Mg,K e Na were greater in the main channel sediments than in the tributaires. Probably the differences in the substrats geology and erosion regimes of the basins account for this patterns, generally. The major basic cation, total phosphorus and carbon concentration were lower in the low Amazon Varzeas. Between the three differents sampling periods, pratically the elements concentration in Varzea sediment was constant. Finally, the datas showed that the most parts of Varzea carbon sediment had it's origin in the fine particulated organic matter transported by the Amazon river. (C.D.G.)

  13. Mutagenicity of chemicals in genetically modified animals

    NARCIS (Netherlands)

    Willems MI; van Benthem J; LEO

    2001-01-01

    The strategy for assessing human health risks of chemicals consists of a large number of tests in different research disciplines. Tests include acute and chronic toxicity, genotoxicity, reproduction toxicity and carcinogenicity. Genotoxic properties of chemicals are assessed in short-term in vitro

  14. Variations in chemical and physical properties of Amazon forest soils in relation to their genesis

    OpenAIRE

    C. A. Quesada; Lloyd, J; M. Schwarz; S. Patiño; Baker, T R; Czimczik, C.; Fyllas, N. M.; Martinelli, L.; G. B. Nardoto; Schmerler, J.; A. J. B. Santos; Hodnett, M. G.; Herrera, R.; Luizão, F.J.; A. Arneth

    2010-01-01

    Soil samples were collected in six South American countries in a total of 71 different 1 ha forest plots across the Amazon Basin as part of the RAINFOR project. They were analysed for total and exchangeable cations, C, N, pH with various P fractions also determined. Physical properties were also examined and an index of soil physical quality proposed. A diverse range of soils was found. For the western areas near the Andean cordillera and the southern and northern fringes, soils tend to be di...

  15. Chemical and physical properties of Amazon forest soils in relation to their genesis

    OpenAIRE

    C. A. Quesada; Lloyd, J; M. Schwarz; S. Patiño; Baker, T R; Czimczik, C.; Fyllas, N. M.; Martinelli, L.; G. B. Nardoto; Schmerler, J.; A. J. B. Santos; Hodnett, M. G.; Herrera, R.; Luizão, F.J.; A. Arneth

    2009-01-01

    Soil samples were collected in six South American countries in a total of 71 different 1 ha forest plots across the Amazon Basin as part of the RAINFOR project. They were analysed for total and exchangeable cations, C, N, pH with various P fractions also determined. Physical properties were also examined and an index of soil physical quality proposed. A diverse range of soils was found. For the western areas near the Andean cordillera and the southern and northern fringes, soils tend to be di...

  16. Aerosol Physical and Chemical Properties Before and After the Manaus Plume in the GoAmazon2014 Experiment

    Science.gov (United States)

    Artaxo, P.; Barbosa, H. M.; Ferreira De Brito, J.; Wurm, F.; Holanda, B. A.; Carbone, S.; Arana, A.; Cirino, G. G.; Souza, R. A. F. D.; Rizzo, L. V.; Martin, S. T.; Andreae, M. O.; Holben, B. N.; Schafer, J.

    2014-12-01

    As part of the GoAmazon2014 experiment, several aerosol and trace gas monitoring stations are being operated for at least one year before and after the Manaus plume. Three sites are being operated in pristine conditions, with atmospheric properties under natural biogenic conditions. These three sites called T0 are: ATTO (Amazon Tall Tower Observatory), ZF2 ecological research site and a third site called EMBRAPA. After the air masses are exposed to the Manaus plume, one site (called T2) is being operated right on the opposite side of the Negro River under the direct influence of the Manaus plume at 5 Km downwind of Manaus. Finally, at about 150 Km downwind of Manaus is the T3 Manacapuru site. Aerosol chemical composition is being analyzed using filters for fine (PM2.5) and coarse mode aerosol as well as three Aerodyne ACSM (Aerosol Chemical Speciation Monitors) instruments. Aerosol absorption is being studied with several aethalometers and MAAP (Multi Angle Absorption Photometers). Aerosol light scattering are being measured at several wavelengths using nephelometers. Aerosol size distribution is determined using scanning mobility particle sizers. The aerosol column is measures using AERONET sunphotometers before and after the Manaus plume, as well as several Lidar systems. The three sites before the Manaus plume show remarkable similar variability in aerosol concentrations and optical properties. This pattern is very different at the T2 site, with large aerosol concentrations enhancing aerosol absorption and scattering significantly. The aerosol is very oxidized before being exposed to the Manaus plume, and this pattern changes significantly for T2 and T3 sites, with a much higher presence of less oxidized aerosol. Typical ozone concentrations at mid-day before Manaus plume is a low 10-12 ppb, value that changes to 50-70 ppb for air masses suffering the influence of Manaus plume. A detailed comparison of aerosol characteristics and composition for the several

  17. [Adsorption of phenol chemicals by surfactant-modified zeolites].

    Science.gov (United States)

    Xie, Jie; Wang, Zhe; Wu, De-Yi; Li, Chun-Jie

    2012-12-01

    Two kinds of zeolites were prepared from fly ash and modified by surfactant subsequently. Surfactant-modified zeolites were studied for adsorption of phenol chemicals (phenol, p-chlorphenol, bisphenol A). It showed that the adsorption affinity of zeolite to phenol chemicals was significantly improved after surfactant modification. The adsorption isotherms of phenol chemicals were well fitted by the Langmuir isotherm. For the two surfactant-surfactant modified zeolites, the maximum adsorption amounts of phenol, p-chlorphenol, and bisphenol A calculated from the Langmuir equation were 37.7, 52.36, 90.9 mg x g(-1) and 10.7, 22.83, 56.8 mg x g(-1), respectively. When pH values of solutions were higher than the pK(a) values of phenol chemicals, the removal efficiencies were getting higher with the increase of pH values. The octanol/water partition coefficient (K(ow)) was also found to be an important factor affecting adsorption of phenol chemicals by the modified zeolites. Higher K(ow) value, which means the greater hydrophobicity of the chemicals, resulted in a higher removal.

  18. Chemically-Modified Cellulose Paper as a Microstructured Catalytic Reactor

    Directory of Open Access Journals (Sweden)

    Hirotaka Koga

    2015-01-01

    Full Text Available We discuss the successful use of chemically-modified cellulose paper as a microstructured catalytic reactor for the production of useful chemicals. The chemical modification of cellulose paper was achieved using a silane-coupling technique. Amine-modified paper was directly used as a base catalyst for the Knoevenagel condensation reaction. Methacrylate-modified paper was used for the immobilization of lipase and then in nonaqueous transesterification processes. These catalytic paper materials offer high reaction efficiencies and have excellent practical properties. We suggest that the paper-specific interconnected microstructure with pulp fiber networks provides fast mixing of the reactants and efficient transport of the reactants to the catalytically-active sites. This concept is expected to be a promising route to green and sustainable chemistry.

  19. Biosorption of uranium by chemically modified Rhodotorula glutinis

    Energy Technology Data Exchange (ETDEWEB)

    Bai Jing, E-mail: baijing@impcas.ac.c [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Yao Huijun [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Fan Fangli; Lin Maosheng [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang Lina; Ding Huajie; Lei Fuan; Wu Xiaolei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li, Xiaofei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Guo Junsheng; Qin Zhi [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2010-11-15

    The present paper reports the biosorption of uranium onto chemically modified yeast cells, Rhodotorula glutinis, in order to study the role played by various functional groups in the cell wall. Esterification of the carboxyl groups and methylation of the amino groups present in the cells were carried out by methanol and formaldehyde treatment, respectively. The uranium sorption capacity increased 31% for the methanol-treated biomass and 11% for the formaldehyde-treated biomass at an initial uranium concentration of 140 mg/L. The enhancement of uranium sorption capacity was investigated by Fourier transform infrared (FTIR) spectroscopy analysis, with amino and carboxyl groups were determined to be the important functional groups involved in uranium binding. The biosorption isotherms of uranium onto the raw and chemically modified biomass were also investigated with varying uranium concentrations. Langmuir and Freundlich models were well able to explain the sorption equilibrium data with satisfactory correlation coefficients higher than 0.9. -- Research highlights: {yields} Uranium biosorption on to chemically modified yeast cells {yields} Cells before and after uranium sorption were investigate by FTIR spectroscopy {yields} Amino and carboxyl groups were important functional groups involved in uranium binding {yields} The sorption equilibrium date of raw and chemically modified biomass fitted well with Langmuir and Freundlich models

  20. Modified NASA-Lewis Chemical Equilibrium Code for MHD applications

    Energy Technology Data Exchange (ETDEWEB)

    Sacks, R. A.; Geyer, H. K.; Grammel, S. J.; Doss, E. D.

    1979-12-01

    A substantially modified version of the NASA-Lewis Chemical Equilibrium Code has recently been developed. The modifications were designed to extend the power and convenience of the Code as a tool for performing combustor analysis for MHD systems studies. This report describes the effect of the programming details from a user point of view, but does not describe the Code in detail.

  1. Structure and biological activity of chemically modified nisin A species

    NARCIS (Netherlands)

    Rollema, Harry S.; Metzger, Jörg W.; Both, Paula; Kuipers, Oscar P.; Siezen, Roland J.

    1996-01-01

    Nisin, a 34-residue peptide bacteriocin, contains the less common amino acids lanthionine, β-methyllanthionine, dehydroalanine (Dha), and dehydrobutyrine (Dhb). Several chemically modified nisin A species were purified by reverse-phase HPLC and characterized by two-dimensional NMR and electrospray m

  2. Modified NASA-Lewis chemical equilibrium code for MHD applications

    Science.gov (United States)

    Sacks, R. A.; Geyer, H. K.; Grammel, S. J.; Doss, E. D.

    1979-01-01

    A substantially modified version of the NASA-Lewis Chemical Equilibrium Code was recently developed. The modifications were designed to extend the power and convenience of the Code as a tool for performing combustor analysis for MHD systems studies. The effect of the programming details is described from a user point of view.

  3. Influence of temperature on natural and chemically modified zeolites

    International Nuclear Information System (INIS)

    Zeolites from Nizny Hrabovec (Slovak Republic) were modified with solutions of NaOH. The changes of zeolites in the temperature range 20-1200 deg C were studied by thermal analysis (DTA, TG, ETA), X-ray analysis and REM analysis. Thermal analysis showed that the process of dehydration started between temperatures 20 and 600 deg C, over this temperature the dealumination and structural changes have taken place. X-ray analysis and REM analysis showed the structural changes of natural zeolites and gradual loss of cristallinity of the chemically modified zeolites. (author)

  4. Chemical sensors based on molecularly modified metallic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Haick, Hossam [Department of Chemical Engineering and Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, Haifa 32000 (Israel)

    2007-12-07

    This paper presents a concise, although admittedly non-exhaustive, didactic review of some of the main concepts and approaches related to the use of molecularly modified metal nanoparticles in or as chemical sensors. This paper attempts to pull together different views and terminologies used in sensors based on molecularly modified metal nanoparticles, including those established upon electrochemical, optical, surface Plasmon resonance, piezoelectric and electrical transduction approaches. Finally, this paper discusses briefly the main advantages and disadvantages of each of the presented class of sensors. (review article)

  5. Chemical Composition and Larvicidal Activity of Essential Oils Extracted from Brazilian Legal Amazon Plants against Aedes aegypti L. (Diptera: Culicidae)

    Science.gov (United States)

    Dias, Clarice Noleto; Alves, Luciana Patrícia Lima; Rodrigues, Klinger Antonio da Franca; Brito, Maria Cristiane Aranha; Rosa, Carliane dos Santos; do Amaral, Flavia Maria Mendonça; Monteiro, Odair dos Santos; Andrade, Eloisa Helena de Aguiar; Maia, José Guilherme Soares; Moraes, Denise Fernandes Coutinho

    2015-01-01

    The mosquito Aedes aegypti L. (Diptera: Culicidae) is the major vector of dengue and chikungunya fever. The lack of effective therapies and vaccines for these diseases highlights the need for alternative strategies to control the spread of virus. Therefore, this study investigated the larvicidal potential of essential oils from common plant species obtained from the Chapada das Mesas National Park, Brazil, against third instar A. aegypti larvae. The chemical composition of these oils was determined by gas chromatography coupled to mass spectrometry. The essential oils of Eugenia piauhiensis Vellaff., Myrcia erythroxylon O. Berg, Psidium myrsinites DC., and Siparuna camporum (Tul.) A. DC. were observed to be mainly composed of sesquiterpene hydrocarbons. The essential oil of Lippia gracilis Schauer was composed of oxygenated monoterpenes. Four of the five tested oils were effective against the A. aegypti larvae, with the lethal concentration (LC50) ranging from 230 to 292 mg/L after 24 h of exposure. Overall, this work demonstrated the possibility of developing larvicidal products against A. aegypti by using essential oils from the flora of the Brazilian Legal Amazon. This in turn demonstrates the potential of using natural resources for the control of disease vectors. PMID:25949264

  6. Chemical Composition and Larvicidal Activity of Essential Oils Extracted from Brazilian Legal Amazon Plants against Aedes aegypti L. (Diptera: Culicidae).

    Science.gov (United States)

    Dias, Clarice Noleto; Alves, Luciana Patrícia Lima; Rodrigues, Klinger Antonio da Franca; Brito, Maria Cristiane Aranha; Rosa, Carliane Dos Santos; do Amaral, Flavia Maria Mendonça; Monteiro, Odair Dos Santos; Andrade, Eloisa Helena de Aguiar; Maia, José Guilherme Soares; Moraes, Denise Fernandes Coutinho

    2015-01-01

    The mosquito Aedes aegypti L. (Diptera: Culicidae) is the major vector of dengue and chikungunya fever. The lack of effective therapies and vaccines for these diseases highlights the need for alternative strategies to control the spread of virus. Therefore, this study investigated the larvicidal potential of essential oils from common plant species obtained from the Chapada das Mesas National Park, Brazil, against third instar A. aegypti larvae. The chemical composition of these oils was determined by gas chromatography coupled to mass spectrometry. The essential oils of Eugenia piauhiensis Vellaff., Myrcia erythroxylon O. Berg, Psidium myrsinites DC., and Siparuna camporum (Tul.) A. DC. were observed to be mainly composed of sesquiterpene hydrocarbons. The essential oil of Lippia gracilis Schauer was composed of oxygenated monoterpenes. Four of the five tested oils were effective against the A. aegypti larvae, with the lethal concentration (LC50) ranging from 230 to 292 mg/L after 24 h of exposure. Overall, this work demonstrated the possibility of developing larvicidal products against A. aegypti by using essential oils from the flora of the Brazilian Legal Amazon. This in turn demonstrates the potential of using natural resources for the control of disease vectors. PMID:25949264

  7. Chemical Composition and Larvicidal Activity of Essential Oils Extracted from Brazilian Legal Amazon Plants against Aedes aegypti L. (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Clarice Noleto Dias

    2015-01-01

    Full Text Available The mosquito Aedes aegypti L. (Diptera: Culicidae is the major vector of dengue and chikungunya fever. The lack of effective therapies and vaccines for these diseases highlights the need for alternative strategies to control the spread of virus. Therefore, this study investigated the larvicidal potential of essential oils from common plant species obtained from the Chapada das Mesas National Park, Brazil, against third instar A. aegypti larvae. The chemical composition of these oils was determined by gas chromatography coupled to mass spectrometry. The essential oils of Eugenia piauhiensis Vellaff., Myrcia erythroxylon O. Berg, Psidium myrsinites DC., and Siparuna camporum (Tul. A. DC. were observed to be mainly composed of sesquiterpene hydrocarbons. The essential oil of Lippia gracilis Schauer was composed of oxygenated monoterpenes. Four of the five tested oils were effective against the A. aegypti larvae, with the lethal concentration (LC50 ranging from 230 to 292 mg/L after 24 h of exposure. Overall, this work demonstrated the possibility of developing larvicidal products against A. aegypti by using essential oils from the flora of the Brazilian Legal Amazon. This in turn demonstrates the potential of using natural resources for the control of disease vectors.

  8. Reduced chemically modified graphene oxide for supercapacitor electrode

    OpenAIRE

    Rajagopalan, Balasubramaniyan; Chung, Jin Suk

    2014-01-01

    An efficient active material for supercapacitor electrodes is prepared by reacting potassium hydroxide (KOH) with graphene oxide followed by chemical reduction with hydrazine. The electrochemical performance of KOH treated graphene oxide reduced for 24 h (reduced chemically modified graphene oxide, RCMGO-24) exhibits a specific capacitance of 253 F g-1 at 0.2 A g-1 in 2 M H2SO4 compared to a value of 141 F g-1 for graphene oxide reduced for 24 h (RGO-24), and good cyclic stability up to 3,000...

  9. THE INDUSTRIAL UTILIZATION OF CHEMICAL MODIFIED AGRICULTURAL RESIDUES

    Institute of Scientific and Technical Information of China (English)

    Feng Xu; Runcang Sun; Huaiyu Zhan

    2004-01-01

    Various lignocellulosic materials such as wood,agricultural and forest residues has the potential to be valuable substitute for, or complement to,commercial sorbents for removing heavy metal ions or dyes from waste water or spilled oil from inland water or sea. More than 9 million tons of straw pulp are produced annually in china, which account for about 90% of the world′s total straw pulp. However,huge quantity of remain straw is not used as industrial raw material and is burnt in the fields or on the side of road. These resources can be chemical modified such as acetylation. Modified straws have the characteristics of low cost, high capacity, quick uptake, and easy to desorb. This paper reviews the current status of the technology for modified agricultural residues, which focus on hemicellulose and cellulose. The potential of these natural sorbents in main industry is also indicated.

  10. THE INDUSTRIAL UTILIZATION OF CHEMICAL MODIFIED AGRICULTURAL RESIDUES

    Institute of Scientific and Technical Information of China (English)

    FengXu; RuncangSun; HuaiyuZhan

    2004-01-01

    Various lignocellulosic materials such as wood, agricultural and forest residues has the potential to be valuable substitute for, or complement to, commercial sorbents for removing heavy metal ions or dyes from waste water or spilled oil from inland water or sea. More than 9 million tons of straw pulp are produced annually in china, which account for about 90% of the world's total straw pulp. However, huge quantity of remain straw is not used as industrial raw material and is burnt in the fields or on the side of road. These resources can be chemical modified such as acetylation. Modified straws have the characteristics of low cost, high capacity, quick uptake, and easy to desorb. This paper reviews the current status of the technology for modified agricultural residues, which focus on hemicellulose and cellulose. The potential of these natural sorbents in main industry is also indicated.

  11. Chemical characteristics and volatile profile of genetically modified peanut cultivars.

    Science.gov (United States)

    Ng, Ee Chin; Dunford, Nurhan T; Chenault, Kelly

    2008-10-01

    Genetic engineering has been used to modify peanut cultivars for improving agronomic performance and pest resistance. Food products developed through genetic engineering have to be assessed for their safety before approval for human consumption. Preservation of desirable chemical, flavor and aroma attributes of the peanut cultivars during the genetic modifications is critical for acceptance of genetically modified peanuts (GMP) by the food industry. Hence, the main objective of this study is to examine chemical characteristics and volatile profile of GMP. The genetically modified peanut cultivars, 188, 540 and 654 were obtained from the USDA-ARS in Stillwater, Oklahoma. The peanut variety Okrun was examined as a control. The volatile analysis was performed using a gas chromatograph/mass spectrometer (GC/MS) equipped with an olfactory detector. The peanut samples were also analyzed for their moisture, ash, protein, sugar and oil compositions. Experimental results showed that the variations in nutritional composition of peanut lines examined in this study were within the values reported for existing cultivars. There were minor differences in volatile profile among the samples. The implication of this study is significant, since it shows that peanut cultivars with greater pest and fungal resistance were successfully developed without major changes in their chemical characteristics.

  12. Chemical characteristics and volatile profile of genetically modified peanut cultivars.

    Science.gov (United States)

    Ng, Ee Chin; Dunford, Nurhan T; Chenault, Kelly

    2008-10-01

    Genetic engineering has been used to modify peanut cultivars for improving agronomic performance and pest resistance. Food products developed through genetic engineering have to be assessed for their safety before approval for human consumption. Preservation of desirable chemical, flavor and aroma attributes of the peanut cultivars during the genetic modifications is critical for acceptance of genetically modified peanuts (GMP) by the food industry. Hence, the main objective of this study is to examine chemical characteristics and volatile profile of GMP. The genetically modified peanut cultivars, 188, 540 and 654 were obtained from the USDA-ARS in Stillwater, Oklahoma. The peanut variety Okrun was examined as a control. The volatile analysis was performed using a gas chromatograph/mass spectrometer (GC/MS) equipped with an olfactory detector. The peanut samples were also analyzed for their moisture, ash, protein, sugar and oil compositions. Experimental results showed that the variations in nutritional composition of peanut lines examined in this study were within the values reported for existing cultivars. There were minor differences in volatile profile among the samples. The implication of this study is significant, since it shows that peanut cultivars with greater pest and fungal resistance were successfully developed without major changes in their chemical characteristics. PMID:19000610

  13. Film forming capacity of chemically modified corn starches.

    Science.gov (United States)

    López, Olivia V; García, María A; Zaritzky, Noemí E

    2008-09-01

    Native starch can be chemically modified to improve its functionality and to expand its uses. Modified starches were characterized and the rheological behavior of filmogenic suspensions was analyzed. The film forming capacity of different chemical modified corn starches was evaluated. Acetylated starch was selected by the characteristics of the resulted films; its optimum concentration was 5% w/w since their films exhibited the lowest water vapor permeability (WVP, 1.26×10(-10)g/msPa). The effect of glycerol as plasticizer on film properties depend on its concentration, being 1.5% w/w those that allows to obtain the lowest WVP value (1.64×10(-11)g/msPa), low film solubility in water and a more compact structure than those of unplasticized films. Mechanical behavior of plasticized acetylated starch films depends on glycerol concentration, being rigid and brittle the unplasticized ones, ductile those containing 1.5% w/w of glycerol and very flexible those with a higher plasticizer content. PMID:26048223

  14. Chemically modified oligonucleotides with efficient RNase H response

    DEFF Research Database (Denmark)

    Vester, Birte; Boel, Anne Marie; Lobedanz, Sune;

    2008-01-01

    Ten different chemically modified nucleosides were incorporated into short DNA strands (chimeric oligonucleotides ON3-ON12 and ON15-ON24) and then tested for their capacity to mediate RNAse H cleavage of the complementary RNA strand. The modifications were placed at two central positions directly...... in the RNase H cleaving region. The RNA strand of duplexes with ON3, ON5 and ON12 were cleaved more efficiently than the RNA strand of the DNA:RNA control duplex. There seems to be no correlation between the thermal stability between the duplexes and RNase H cleavage....

  15. Chemically modified tetracyclines: The novel host modulating agents

    Directory of Open Access Journals (Sweden)

    Devulapalli Narasimha Swamy

    2015-01-01

    Full Text Available Periodontal pathogens and destructive host responses are involved in the initiation and progression of periodontitis. The emergence of host response modulation as a treatment concept has resulted from our improved understanding of the pathogenesis of periodontal disease. A variety of drugs have been evaluated as host modulation agents (HMA, including Non Steroidal Anti Inflammatory Drugs (NSAIDS, bisphosphonates, tetracyclines, enamel matrix proteins and bone morphogenetic proteins. Chemically modified tetracyclines (CMTs are one such group of drugs which have been viewed as potential host modulating agents by their anticollagenolytic property. The CMTs are designed to be more potent inhibitors of pro inflammatory mediators and can increase the levels of anti inflammatory mediators.

  16. Mechano-sorptive creep of Portuguese pinewood chemically modified

    Directory of Open Access Journals (Sweden)

    Barroso Lopes Duarte

    2014-03-01

    Full Text Available The effect of chemical modification on mechano-sorptive creep in bending was studied by experimental work. Stakes with 20 × 20 × 400 mm RTL of Portuguese wood species (Pinus pinaster Aiton modified with 1,3-dimethylol-4,5- dihydroxyethyleneurea (DMDHEU, m-methylated melamine resin (MMF, tetraethoxysilane (TEOS and amid wax (WA were measured under asymmetric moistening conditions over a period of 42 days (app. 1000 hours with stress level (SL of 12 MPa, according to ENV 1156.

  17. Chemically modified tetracyclines: The novel host modulating agents.

    Science.gov (United States)

    Swamy, Devulapalli Narasimha; Sanivarapu, Sahitya; Moogla, Srinivas; Kapalavai, Vasavi

    2015-01-01

    Periodontal pathogens and destructive host responses are involved in the initiation and progression of periodontitis. The emergence of host response modulation as a treatment concept has resulted from our improved understanding of the pathogenesis of periodontal disease. A variety of drugs have been evaluated as host modulation agents (HMA), including Non Steroidal Anti Inflammatory Drugs (NSAIDS), bisphosphonates, tetracyclines, enamel matrix proteins and bone morphogenetic proteins. Chemically modified tetracyclines (CMTs) are one such group of drugs which have been viewed as potential host modulating agents by their anticollagenolytic property. The CMTs are designed to be more potent inhibitors of pro inflammatory mediators and can increase the levels of anti inflammatory mediators. PMID:26392682

  18. Probing Chromatin-modifying Enzymes with Chemical Tools

    KAUST Repository

    Fischle, Wolfgang

    2016-02-04

    Chromatin is the universal template of genetic information in all eukaryotic organisms. Chemical modifications of the DNA-packaging histone proteins and the DNA bases are crucial signaling events in directing the use and readout of eukaryotic genomes. The enzymes that install and remove these chromatin modifications as well as the proteins that bind these marks govern information that goes beyond the sequence of DNA. Therefore, these so-called epigenetic regulators are intensively studied and represent promising drug targets in modern medicine. We summarize and discuss recent advances in the field of chemical biology that have provided chromatin research with sophisticated tools for investigating the composition, activity, and target sites of chromatin modifying enzymes and reader proteins.

  19. Band bending and electrical transport at chemically modified silicon surfaces

    Science.gov (United States)

    Lopinski, Greg; Ward, Tim; Hul'Ko, Oleksa; Boukherroub, Rabah

    2002-03-01

    High resolution electron energy loss spectroscopy (HREELS) and electrical transport measurements have been used to investigate how various chemical modifications give rise to band bending and alter the conductivity of Si(111) surfaces. HREELS is a sensitive probe of band bending through observations of the low frequency free carrier plasmon mode. For hydrogen terminated surfaces, prepared by the standard etch in ammonium flouride, HREELS measurements on both n and n+ substrates are consistent with nearly flat bands. Chlorination of these surfaces results in substantial upward band bending due to the strong electron withdrawing nature of the chlorine, driving the surface into inversion. The presence of this inversion layer on high resistivity n-type samples is observed through a substantial enhancement of the surface conductivity (relative to the H-terminated surface), as well as through broadening of the quasi-elastic peak in the HREELS measurements. We have also begun to examine organically modified silicon surfaces, prepared by various wet chemical reactions with the H-terminated surface. Decyl modified Si(111) surfaces are seen to exhibit a small degree of band bending, attributed to extrinsic defect states cause by a small degree of oxidation accompanying the modification reaction. The prospects of using conductivity as an in-situ monitor of the rate of these reactions will be discussed.

  20. Chemical Composition, Antioxidant, and Antimicrobial Activities of Essential Oils of Endlicheria arenosa (Lauraceae) from the Amazon.

    Science.gov (United States)

    da Silva, Joyce Kelly R; da Trindade, Rafaela C S; Maia, José Guilherme S; Setzer, William N

    2016-05-01

    The essential oils (EOs) of leaves and twigs of Endlicheria arenosa Chanderb. were obtained by hydrodistillation using a Clevenger-type apparatus and the chemical composition was determined by GC and GC-MS. In total, 47 constituents were identified and sesquiterpene hydrocarbons (77.6%) were the main compounds found in the leaf EO, such as bicyclogermacrene (42.2%), germacrene D (12.5%) and β-caryophyllene (10.1%). Limonene (33.2%), terpinen-4-ol (15.6%) and δ-cadinol (6.9%) were the predominant constituents in the EO of the twigs. Using the DPPH radical-scavenging method, the EO of the leaves showed the greater radical-scavenging activity (216.5 ± 11.6 mg Trolox equivalents (TE)/mL compared to the EO of the twigs (122.6 ± 6.8 mg TE/mL). Also, the EO of leaves displayed promising antimicrobial activity against Escherichia coli (MIC 19.5 μg x mL(-1)). The present study is the first report about evaluation of volatile oils for this species. PMID:27319154

  1. Maltodextrins from chemically modified starches. Selected physicochemical properties.

    Science.gov (United States)

    Pycia, Karolina; Juszczak, Lesław; Gałkowska, Dorota; Witczak, Mariusz; Jaworska, Grażyna

    2016-08-01

    The aim of this work was to evaluate the effect of chemical modification of starch (cross-linking and/or stabilisation) on selected rheological and functional properties of maltodextrins of dextrose equivalent of 6, 11 and 16. It was found that values of glass transition temperatures were decreasing with dextrose equivalent of maltodextrin. The highest values of glass transition temperature (TG) were determined for maltodextrin of DE 6-obtained from distarch phosphate and acetylated distarch phosphate. Increase in DE value of maltodextrin was also accompanied by decrease and increase in values of intrinsic viscosity and the critical concentration, respectively; however, there was no significant effect of kind of chemical modification of starch on the values of these parameters. Maltodextrin solutions at concentrations of from 10 to 70 % exhibited Newtonian flow behaviour. In the case of 50% solutions of maltodextrins of DE 6 the highest viscosity was produced by maltodextrin from native potato starch, while the lowest one by maltodextrin from acetylated starch. On the other hand, among the maltodextrin of DE 11 this one produced from acetylated starch showed the highest viscosity. All the maltodextrins exhibited surfactant properties in a water-air system, with the strongest effect observed for maltodextrins produced from double chemically modified starches and from acetylated starch. The surface activity was increasing with increasing of the DE value of maltodextrin. Moreover, values of surface tension were decreasing with increasing in maltodextrin concentration in the system. PMID:27112878

  2. Modelling Amperometric Biosensors Based on Chemically Modified Electrodes

    Science.gov (United States)

    Baronas, Romas; Kulys, Juozas

    2008-01-01

    The response of an amperometric biosensor based on a chemically modified electrode was modelled numerically. A mathematical model of the biosensor is based on a system of non-linear reaction-diffusion equations. The modelling biosensor comprises two compartments: an enzyme layer and an outer diffusion layer. In order to define the main governing parameters the corresponding dimensionless mathematical model was derived. The digital simulation was carried out using the finite difference technique. The adequacy of the model was evaluated using analytical solutions known for very specific cases of the model parameters. By changing model parameters the output results were numerically analyzed at transition and steady state conditions. The influence of the substrate and mediator concentrations as well as of the thicknesses of the enzyme and diffusion layers on the biosensor response was investigated. Calculations showed complex kinetics of the biosensor response, especially when the biosensor acts under a mixed limitation of the diffusion and the enzyme interaction with the substrate.

  3. 12-Tungstophosphates Immobilized on Chemically Modified Mesoporous Silica SBA-15

    Institute of Scientific and Technical Information of China (English)

    ZHU Jing; YOU Wan-sheng; ZHU Zai-ming; SUN Zhen-gang; ZHANG Lan-cui; GU Yuan-peng

    2005-01-01

    A functionalized material, PW/SBA-15m, was prepared successfully in diluted H2SO4 aqueous solutions by immobilizing 12-tungstophosphates on chemically modified mesoporous silica SBA-15 and characterized by elemental analysis, FTIR, 31P MAS NMR, XRD and TEM. The results indicate that the framework of SBA-15 and the Keggin structure of PW12O3-40 were retained, and that 23%-33%(mass fraction) of PW12O3-40 was immobilized; the PW12O3-40 anions were finely dispersed on the pore wall of SBA-15. Having been leached in ethanol at 60 ℃ for 7 h, the loss of PW12O3-40 anions was not found.

  4. Highly efficient adsorption of chlorophenols onto chemically modified chitosan

    Science.gov (United States)

    Zhou, Liang-Chun; Meng, Xiang-Guang; Fu, Jing-Wei; Yang, Yu-Chong; Yang, Peng; Mi, Chun

    2014-02-01

    A novel chemically modified chitosan CS-SA-CD with phenol and β-cyclodextrin groups was prepared. The adsorptions of phenol, 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP) on the functional chitosan from aqueous solution were investigated. CS-SA-CD exhibited excellent adsorption ability for chlorophenols especially for DCP and TCP. The maximum adsorption capacities of phenol, 2-CP, 4-CP, DCP and TCP on CS-SA-CD were 59.74, 70.52, 96.43, 315.46 and 375.94 mg/g, respectively. The scanning electron microscope and Brunauer-Emmett-Teller analyses revealed that the introduction of phenol group changed the surface morphology and surface properties of chitosan. The modified chitosan CS-SA-CD possesses larger surface areas (4.72 m2/g), pore volume (7.29 × 10-3 mL/g) and average pore diameter (59.99 Å) as compared to those of chitosan 3.27 m2/g, 2.00 × 10-3 mL/g and 15.95 Å, respectively. The enhanced adsorption of chlorophenols was also attributed to the interaction of hydrogen bond between Cl atom and sbnd OH group. The adsorption of chlorophenols on CS-SA-CD followed the pseudo-second-order kinetic model. Adsorbent could be regenerated easily and the regenerated CS-SA-CD remained 80-91% adsorption efficiency.

  5. Highly efficient adsorption of chlorophenols onto chemically modified chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Liang-Chun [Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064 (China); National Center for Packaging Material Quality Supervision and Inspection, Chengdu Institute of Product Quality Supervision and Inspection, Chengdu 610064 (China); Meng, Xiang-Guang, E-mail: mengxgchem@163.com [Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064 (China); Fu, Jing-Wei [National Center for Packaging Material Quality Supervision and Inspection, Chengdu Institute of Product Quality Supervision and Inspection, Chengdu 610064 (China); Yang, Yu-Chong; Yang, Peng; Mi, Chun [Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064 (China)

    2014-02-15

    A novel chemically modified chitosan CS-SA-CD with phenol and β-cyclodextrin groups was prepared. The adsorptions of phenol, 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (DCP) and 2,4,6-trichlorophenol (TCP) on the functional chitosan from aqueous solution were investigated. CS-SA-CD exhibited excellent adsorption ability for chlorophenols especially for DCP and TCP. The maximum adsorption capacities of phenol, 2-CP, 4-CP, DCP and TCP on CS-SA-CD were 59.74, 70.52, 96.43, 315.46 and 375.94 mg/g, respectively. The scanning electron microscope and Brunauer–Emmett–Teller analyses revealed that the introduction of phenol group changed the surface morphology and surface properties of chitosan. The modified chitosan CS-SA-CD possesses larger surface areas (4.72 m{sup 2}/g), pore volume (7.29 × 10{sup −3} mL/g) and average pore diameter (59.99 Å) as compared to those of chitosan 3.27 m{sup 2}/g, 2.00 × 10{sup −3} mL/g and 15.95 Å, respectively. The enhanced adsorption of chlorophenols was also attributed to the interaction of hydrogen bond between Cl atom and -OH group. The adsorption of chlorophenols on CS-SA-CD followed the pseudo-second-order kinetic model. Adsorbent could be regenerated easily and the regenerated CS-SA-CD remained 80–91% adsorption efficiency.

  6. Observations and Modeling of the Green Ocean Amazon 2014/15: Hydroxyl Radical (OH) Chemical Ionization Mass Spectrometer (CIMS) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Saewung [Univ. of California, Irvine, CA (United States)

    2016-05-01

    The University of California, Irvine, science team (Dr. Saewung Kim, Dr. Roger Seco, Dr. Alex Guenther, and Dr. Jim Smith) deployed a chemical ionization mass spectrometer system for hydroxyl radical (OH) and sulfuric acid quantifications. As part of the GoAmazon 2014/15 field campaign. Hydroxyl radical determines tropospheric oxidation capacity and had been expected to be very low in the pristine rain forest region such as the Brazilian Amazon because of the presence of significant levels of highly reactive biogenic volatile organic compounds and very low levels of NO, which is an OH recycling agent. However, several recent in situ OH observations provided by a laser-induced fluorescence system reported unaccountably high OH concentrations. To address this discrepancy, a series of laboratory and theoretical studies has postulated chemical reaction mechanisms of isoprene that may regenerate OH in photo-oxidation processes. Along with these efforts, potential artifacts on the laser induced fluorescence system from isoprene and its oxidation products also have been explored. Therefore, the first chemical ionization mass spectrometer observations at the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s T3 site in Manacapuru, Brazil, are expected to provide a critical experimental constraint to address uncertainty in constraining oxidation capacity over pristine rain forest environments. In addition, we deployed a National Center for Atmospheric Research (NCAR) proton transfer reaction time-of-flight mass spectrometer to characterize atmospheric volatile organic compound levels, especially isoprene and its oxidation products, which are critical input parameters for box modeling to simulate OH with different isoprene photo-oxidation schemes. As there has been no report on noticeable new particle formation events, our first in situ sulfuric acid observations in the Amazon rain forest were expected to constrain the

  7. Modelling Amperometric Biosensors Based on Chemically Modified Electrodes

    Directory of Open Access Journals (Sweden)

    Juozas Kulys

    2008-08-01

    Full Text Available The response of an amperometric biosensor based on a chemically modified electrode was modelled numerically. A mathematical model of the biosensor is based on a system of non-linear reaction-diffusion equations. The modelling biosensor comprises two compartments: an enzyme layer and an outer diffusion layer. In order to define the main governing parameters the corresponding dimensionless mathematical model was derived. The digital simulation was carried out using the finite difference technique. The adequacy of the model was evaluated using analytical solutions known for very specific cases of the model parameters. By changing model parameters the output results were numerically analyzed at transition and steady state conditions. The influence of the substrate and mediator concentrations as well as of the thicknesses of the enzyme and diffusion layers on the biosensor response was investigated. Calculations showed complex kinetics of the biosensor response, especially when the biosensor acts under a mixed limitation of the diffusion and the enzyme interaction with the substrate.

  8. Reference field effect transistor based on chemically modified ISFETs

    NARCIS (Netherlands)

    Skowronska-Ptasinska, Maria; Wal, van der Peter D.; Berg, van den Albert; Bergveld, Piet; Sudhölter, Ernst J.R.; Reinhoudt, David N.

    1990-01-01

    Different hydrophobic polymers were used for chemical modification of ion-sensitive field effect transistors (ISFETs) in order to prepare a reference FET (REFET). Chemical attachment of the polymer to the ISFET gate results in a long lifetime of the device. Properties of polyacrylate (polyACE) REFET

  9. CHEMICALLY MODIFIED FIELD-EFFECT TRANSISTORS - POTENTIOMETRIC AG+ SELECTIVITY OF PVC MEMBRANES BASED ON MACROCYCLIC THIOETHERS

    NARCIS (Netherlands)

    BRZOZKA, Z; COBBEN, PLHM; REINHOUDT, DN; EDEMA, JJH; KELLOGG, RM

    1993-01-01

    A chemically modified field-effect transistor (CHEMFET) with satisfactory Ag+ selectivity is described. The potentiometric Ag+ selectivities of CHEMFETs with plasticized PVC membranes based on macrocyclic thioethers have been determined. All the macrocyclic thioethers tested showed silver response a

  10. Antibacterial activity of Brazilian Amazon plant extracts

    OpenAIRE

    Ivana Barbosa Suffredini; Mateus Luís Barradas Paciencia; Antonio Drauzio Varella; Riad Naim Younes

    2006-01-01

    Infections caused by multiresistant bacteria are a widespread problem, especially in intensive care units. New antibiotics are necessary, and we need to search for alternatives, including natural products. Brazil is one of the hottest spots in the world in terms of biodiversity, but little is known about the chemical and pharmacological properties of most of the plants found in the Amazon rain forest and the Atlantic Forest. We screened 1,220 organic and aqueous extracts, obtained from Amazon...

  11. Modified Smith Predictor Based Control Of Cascaded Chemical Reactor

    Directory of Open Access Journals (Sweden)

    Binu P. Mathew

    2014-04-01

    Full Text Available A cascade control with modified smith predictor is used for controlling an open loop unstable time delay process. It has three controllers, one is for servo response other two are for regulatory response. For two disturbance rejection controllers an analytical design method is used by proposing closed loop complementary sensitivity function. These two controllers are PID controller cascaded with second order lead/lag filter. Setpoint tracking controller is designed by using direct synthesis method. The main advantage of this control scheme is that the servo response can be decoupled from the regulatory response.

  12. A Nonantibiotic Chemically Modified Tetracycline (CMT-3) Inhibits Intimal Thickening

    OpenAIRE

    Islam, Muzharul M.; Franco, Christopher D.; Courtman, David W.; Bendeck, Michelle P.

    2003-01-01

    Recent research has shown that the tetracycline antibiotics are pluripotent drugs that inhibit the activity of matrix metalloproteinases (MMPs) and affect many cellular functions including proliferation, migration, and matrix remodeling. We have shown that doxycycline inhibits MMP activity and intimal thickening after injury of the rat carotid artery, however we do not know whether these effects are because of the antibiotic, anti-MMP, or other actions of doxycycline. Recently, chemically mod...

  13. Stripping voltammetric behavior of technetium at various chemically modified electrodes

    International Nuclear Information System (INIS)

    In monitoring of nuclear processing plants and storage facilities the necessity arises of assaying traces of the artificial radioactive element technetium. The oxidation states IV and VII are of particular interest. Stripping voltammetry is among the methods of assay which are suited for this purpose. It allows an enhanced selectivity to be achieved by preconcentration of the analyte and of an oxidation state of the analyte, respectively, at the electrode used. This specific enrichment is successful after appropriate chemical modification of the electrode through immobilization of a Tc-specific reagent. When various approaches of chemical modification of a glassy carbon electrode were examined, the tetraphenylarsonium chloride extractant, which is highly selective with respect to technetium, proved to be the best suited reagent, capable of fixation both by ionic and by covalent bonding on an electrodeposited polymer film. For ionic immobilization the reagent was reacted to m-sulfophenyltriphenyl arsonium and then bound to a copolymer of vinylferrocene and vinylpyridine, which had been provided with cations. It was possible to enrich Tc(VII) at such an electrode and to determine it by stripping voltammetry down to a concentration of 1x10-8 M after 5 minutes enrichment time. (orig./EF)

  14. siRNAmod: A database of experimentally validated chemically modified siRNAs.

    Science.gov (United States)

    Dar, Showkat Ahmad; Thakur, Anamika; Qureshi, Abid; Kumar, Manoj

    2016-01-01

    Small interfering RNA (siRNA) technology has vast potential for functional genomics and development of therapeutics. However, it faces many obstacles predominantly instability of siRNAs due to nuclease digestion and subsequently biologically short half-life. Chemical modifications in siRNAs provide means to overcome these shortcomings and improve their stability and potency. Despite enormous utility bioinformatics resource of these chemically modified siRNAs (cm-siRNAs) is lacking. Therefore, we have developed siRNAmod, a specialized databank for chemically modified siRNAs. Currently, our repository contains a total of 4894 chemically modified-siRNA sequences, comprising 128 unique chemical modifications on different positions with various permutations and combinations. It incorporates important information on siRNA sequence, chemical modification, their number and respective position, structure, simplified molecular input line entry system canonical (SMILES), efficacy of modified siRNA, target gene, cell line, experimental methods, reference etc. It is developed and hosted using Linux Apache MySQL PHP (LAMP) software bundle. Standard user-friendly browse, search facility and analysis tools are also integrated. It would assist in understanding the effect of chemical modifications and further development of stable and efficacious siRNAs for research as well as therapeutics. siRNAmod is freely available at: http://crdd.osdd.net/servers/sirnamod. PMID:26818131

  15. Biosorption of Methylene Blue by Chemically Modified Cellulose Waste

    Institute of Scientific and Technical Information of China (English)

    JIN Yanqiao; ZHANG Yizhuan; Lü Qiufeng; CHENG Xiansu

    2014-01-01

    Citric acid modified cellulose waste (CMCW) was prepared via esterification and used as a low-cost biosorbent for the removal of methylene blue (MB) from aqueous solutions. The effects of biosorbent concentration, initial pH of MB solution, biosorption temperature, contact time, and initial MB concentration on the biosorption of MB were investigated using batch biosorption technique under static conditions. The experimental results showed that CMCW exhibited excellent biosorption characteristics for MB. The maximum biosorption capacity of MB was up to 214.5 mg/g at an adsorption temperature of 293 K. The removal rate of MB onto CMCW reached the maximum at pH>4 and the biosorption reached an equilibrium at about 50 min. The kinetic data can be described well with the pseudo-second-order model and the isotherm data was found to fit the Langmuir isotherm with a monolayer adsorption capacity of 211.42 mg/g. The biosorption appears to be controlled by chemisorption and may be involved in surface adsorption and pore diffusion during the whole biosorption process.

  16. CO2 adsorption on chemically modified activated carbon.

    Science.gov (United States)

    Caglayan, Burcu Selen; Aksoylu, A Erhan

    2013-05-15

    CO2 adsorption capacity of a commercial activated carbon was improved by using HNO3 oxidation, air oxidation, alkali impregnation and heat treatment under helium gas atmosphere. The surface functional groups produced were investigated by diffuse reflectance infrared Fourier transform spectrometer (DRIFTS). CO2 adsorption capacities of the samples were determined by gravimetric analyses for 25-200°C temperature range. DRIFTS studies revealed the formation of carboxylic acid groups on the HNO3 oxidized adsorbents. Increased aromatization and uniform distribution of the Na particles were observed on the samples prepared by Na2CO3 impregnation onto HNO3 oxidized AC support. The adsorption capacities of the nonimpregnated samples were increased by high temperature helium treatments or by increasing the adsorption temperature; both leading to decomposition of surface oxygen groups, forming sites that can easily adsorb CO2. The adsorption capacity loss due to cyclic adsorption/desorption procedures was overcome with further surface stabilization of Na2CO3 modified samples with high temperature He treatments. With Na2CO3 impregnation the mass uptakes of the adsorbents at 20 bars and 25 °C were improved by 8 and 7 folds and at 1 bar were increased 15 and 16 folds, on the average, compared to their air oxidized and nitric acid oxidized supports, respectively. PMID:23500788

  17. PET Imaging and biodistribution of chemically modified bacteriophage MS2.

    Science.gov (United States)

    Farkas, Michelle E; Aanei, Ioana L; Behrens, Christopher R; Tong, Gary J; Murphy, Stephanie T; O'Neil, James P; Francis, Matthew B

    2013-01-01

    The fields of nanotechnology and medicine have merged in the development of new imaging and drug delivery agents based on nanoparticle platforms. As one example, a mutant of bacteriophage MS2 can be differentially modified on the exterior and interior surfaces for the concurrent display of targeting functionalities and payloads, respectively. In order to realize their potential for use in in vivo applications, the biodistribution and circulation properties of this class of agents must first be investigated. A means of modulating and potentially improving the characteristics of nanoparticle agents is the appendage of PEG chains. Both MS2 and MS2-PEG capsids possessing interior DOTA chelators were labeled with (64)Cu and injected intravenously into mice possessing tumor xenografts. Dynamic imaging of the agents was performed using PET-CT on a single animal per sample, and the biodistribution at the terminal time point (24 h) was assessed by gamma counting of the organs ex vivo for 3 animals per agent. Compared to other viral capsids of similar size, the MS2 agents showed longer circulation times. Both MS2 and MS2-PEG bacteriophage behaved similarly, although the latter agent showed significantly less uptake in the spleen. This effect may be attributed to the ability of the PEG chains to mask the capsid charge. Although the tumor uptake of the agents may result from the enhanced permeation and retention (EPR) effect, selective tumor imaging may be achieved in the future by using exterior targeting groups. PMID:23214968

  18. WATER-BLOWN POLYURETHANE RIGID FOAMS MODIFIED BY CHEMICAL PLASTICATION

    Institute of Scientific and Technical Information of China (English)

    YU Ming; XU Qiang

    2006-01-01

    Water-blown polyurethane rigid foams are getting more and more attention, because the traditional blowing agent HCFC141b has already been abolished to prevent the ozone layer from destruction. However, the polyurethane rigid foams blown by water have serious defects, i.e. friability and resulting lower adhesion strength. Thus, the purpose of this study is to resolve the problems by chemical plastication. The maleate was added to polyol-premix containing water or to polyisocyanate,with both of which maleate does not react. To prove the reaction when polyol-premix and polyisocyanate were mixed, the model composite was synthesized and analyzed by IR, NMR and ESI (MS). Furthermore, a series of water-blown polyurethane rigid foams added different amount maleate were successfully prepared. By testing impact strength and adhesion strength of the foams, the actual effect of adding maleate was obtained.

  19. Theory of nanoscale friction on chemically modified graphene

    Science.gov (United States)

    Ko, Jae-Hyeon; Kim, Yong-Hyun

    2013-03-01

    Recently, it is known from FFM experiments that friction force on graphene is significantly increased by chemical modification such as hydrogenation, oxidization, and fluorination, whereas adhesion properties are altered marginally. A novel nanotribological theory on two-dimensional materials is proposed on the basis of experimental results and first-principles density-functional theory (DFT) calculations. The proposed theory indicates that the total lateral stiffness that is the proportional constant of friction force is mostly associated with the out-of-plane bending stiffness of two-dimensional materials. This contrasts to the case of three-dimensional materials, in which the shear strength of materials determines nanoscale friction. We will discuss details of DFT calculations and how to generalize the current theory to three dimensional materials.

  20. Evolution of biomass burning aerosol over the Amazon: airborne measurements of aerosol chemical composition, microphysical properties, mixing state and optical properties during SAMBBA

    Science.gov (United States)

    Morgan, W.; Allan, J. D.; Flynn, M.; Darbyshire, E.; Hodgson, A.; Liu, D.; O'Shea, S.; Bauguitte, S.; Szpek, K.; Johnson, B.; Haywood, J.; Longo, K.; Artaxo, P.; Coe, H.

    2013-12-01

    Biomass burning represents one of the largest sources of particulate matter to the atmosphere, resulting in a significant perturbation to the Earth's radiative balance coupled with serious impacts on public health. On regional scales, the impacts are substantial, particularly in areas such as the Amazon Basin where large, intense and frequent burning occurs on an annual basis for several months. Absorption by atmospheric aerosols is underestimated by models over South America, which points to significant uncertainties relating to Black Carbon (BC) aerosol properties. Initial results from the South American Biomass Burning Analysis (SAMBBA) field experiment, which took place during September and October 2012 over Brazil on-board the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft, are presented here. Aerosol chemical composition was measured by an Aerodyne Aerosol Mass Spectrometer (AMS) and a DMT Single Particle Soot Photometer (SP2). The physical, chemical and optical properties of the aerosols across the region will be characterized in order to establish the impact of biomass burning on regional air quality, weather and climate. The aircraft sampled a range of conditions including sampling of pristine Rainforest, fresh biomass burning plumes, regional haze and elevated biomass burning layers within the free troposphere. The aircraft sampled biomass burning aerosol across the southern Amazon in the states of Rondonia and Mato Grosso, as well as in a Cerrado (Savannah-like) region in Tocantins state. This presented a range of fire conditions, in terms of their number, intensity, vegetation-type and their combustion efficiencies. Near-source sampling of fires in Rainforest environments suggested that smouldering combustion dominated, while flaming combustion dominated in the Cerrado. This led to significant differences in aerosol chemical composition, particularly in terms of the BC content, with BC being enhanced in the Cerrado

  1. Equilibrium and thermodynamic studies of Cd (II) biosorption by chemically modified orange peel.

    Science.gov (United States)

    Kumar, Arbind; Kumar, Vipin

    2016-03-01

    Agricultural wastes have great potential of removing heavy metal ions from aqueous solution. Removal of Cd (II) from aqueous solutions onto chemically modified orange peel was studied at different pH, contact time, initial metal concentrations, adsorbent doses and temperature. Batch experiments were carried out under optimized conditions to evaluate the adsorption capacity of orange peel chemically modified with NaOH. The results showed that maximum adsorption capacity of modified orange peel, approximately 97.0%, was observed 3 mg 1⁻¹ of initial Cd(II) concentration pH 6 for 4 g 1⁻¹ adsorbent dosage, 200 min contact time and 298 K temperature. Adsorption efficiency of modified orange peel decreased with increase in temperature indicated exothermic nature of adsorption. A negative value of ΔG⁰(-8.59 kJ mol⁻¹) confirmed the feasibility of adsorption process and spontaneous nature of adsorption. A negative value of ΔH⁰ (-28.08 kJ mol⁻¹) indicated exothermic nature while a negative ΔS⁰ (-66.86 J K⁻¹ mol⁻¹) value suggested decrease in degree of freedom of the adsorbed species. The results showed that biosorption process of Cd(II) ions by chemically modified orange peel is feasible, spontaneous and exothermic under studied conditions. Chemically by modified orange peel investigated in the present study showed good potential for the removal of cadmium from aqueous solutions. PMID:27097438

  2. Chitosan and chemically modified chitosan beads for acid dyes sorption

    Institute of Scientific and Technical Information of China (English)

    AZLAN Kamari; WAN SAIME Wan Ngah; LAI KEN Liew

    2009-01-01

    The capabilities of chitosan and chitosan-EGDE (ethylene glycol diglycidyl ether) beads for removing Acid Red 37 (AR 37) and Acid Blue 25 (AB 25) from aqueous solution were examined. Chitosan beads were cross-linked with EGDE to enhance its chemical resistance and mechanical strength. Experiments were performed as a function of pH, agitation period and concentration of AR 37 and AB 25. It was shown that the adsorption capacities of chitosan were comparatively higher than chitosan-EGDE for both acid dyes. This is mainly because cross-linking using EGDE reduces the major adsorption sites -NH3+ on chitosan. Langmuir isotherm model showed best conformity compared to Freundlich and BET. The kinetic experimental data agreed very well to the pseudo second-order kinetic model. The desorption study revealed that after three cycles of adsorption and desorption by NaOH and HCl, both adsorbents retained their promising adsorption abilities. FT-IR analysis proved that the adsorption of acid dyes onto chitosan-based adsorbents was a physical adsorption. Results also showed that chitosan and chitosan-EGDE beads were favourable adsorbers and could be employed as low-cost alternatives for the removal of acid dyes in wastewater treatment.

  3. Evaluating Zeolite-Modified Sensors: towards a faster set of chemical sensors

    Science.gov (United States)

    Berna, A. Z.; Vergara, A.; Trincavelli, M.; Huerta, R.; Afonja, A.; Parkin, I. P.; Binions, R.; Trowell, S.

    2011-09-01

    The responses of zeolite-modified sensors, prepared by screen printing layers of chromium titanium oxide (CTO), were compared to unmodified tin oxide sensors using amplitude and transient responses. For transient responses we used a family of features, derived from the exponential moving average (EMA), to characterize chemo-resistive responses. All sensors were tested simultaneously against 20 individual volatile compounds from four chemical groups. The responses of the two types of sensors showed some independence. The zeolite-modified CTO sensors discriminated compounds better using either amplitude response or EMA features and CTO-modified sensors also responded three times faster.

  4. Modified clay minerals efficiency against chemical and biological warfare agents for civil human protection.

    Science.gov (United States)

    Plachá, Daniela; Rosenbergová, Kateřina; Slabotínský, Jiří; Kutláková, Kateřina Mamulová; Studentová, Soňa; Martynková, Gražyna Simha

    2014-04-30

    Sorption efficiencies of modified montmorillonite and vermiculite of their mono ionic Na and organic HDTMA and HDP forms were studied against chemical and biological warfare agents such as yperite and selected bacterial strains. Yperite interactions with modified clay minerals were observed through its capture in low-density polyethylene foil-modified clay composites by measuring yperite gas permeation with using chemical indication and gas chromatography methods. The antibacterial activities of synthetized organoclays were tested against selected Gram-positive and Gram-negative bacterial species in minimum inhibitory concentration tests. The obtained results showed a positive influence of modified clay minerals on the significant yperite breakthrough-time increase. The most effective material was the polyethylene-Na form montmorillonite, while the polyethylene-Na form vermiculite showed the lowest efficiency. With increasing organic cations loading in the interlayer space the montmorillonite efficiency decreased, and in the case of vermiculite an opposite effect was observed. Generally the modified montmorillonites were more effective than modified vermiculites. The HDP cations seem to be more effective compare to the HDTMA. The antibacterial activity tests confirmed efficiency of all organically modified clay minerals against Gram-positive bacteria. The confirmation of antibacterial activity against Y. pestis, plague bacteria, is the most interesting result of this part of the study.

  5. Chemical modifiers in electrothermal atomic absorption determination of Platinum and Palladium containing preparations in blood serum

    Directory of Open Access Journals (Sweden)

    Аntonina Alemasova

    2012-11-01

    Full Text Available The biological liquids matrixes influence on the characteristic masses and repeatability of Pt and Pd electrothermal atomic absorption spectroscopy (ETAAS determination was studied. The chemical modifiers dimethylglyoxime and ascorbic acid for matrix interferences elimination and ETAAS results repeatability improvement were proposed while bioliquids ETAAS analysis, and their action mechanism was discussed.

  6. Changes in soil physical and chemical properties in long term improved natural and traditional agroforestry management systems of cacao genotypes in Peruvian Amazon

    Science.gov (United States)

    Traditional slash and burn agriculture practiced in the Peruvian Amazon region is leading to soil degradation and deforestation of native forest flora. The only way to stop such destructive processes is through the adoptation of sustainable alternatives such as growing crops in agroforestry systems....

  7. Biomechanical properties of acellular sciatic nerves treated with a modified chemical method

    Institute of Scientific and Technical Information of China (English)

    Xinlong Ma; Zhao Yang; Xiaolei Sun; Jianxiong Ma; Xiulan Li; Zhenzhen Yuan; Yang Zhang; Honggang Guo

    2011-01-01

    Nerve grafts are able to adapt to surrounding biomechanical environments if the nerve graft itself exhibits appropriate biomechanical properties (load, elastic modulus, etc.). The present study was designed to determine the differences in biomechanical properties between fresh and chemically acellularized sciatic nerve grafts. Two different chemical methods were used to establish acellular nerve grafts. The nerve was chemically extracted in the Sondell method with a combination of Triton X-100 (nonionic detergent) and sodium deoxycholate (anionic detergent), and in the modified method with a combination of Triton X-200 (anionic detergent), sulfobetaine-10 (SB-10, amphoteric detergents), and sulfobetaine-16 (SB-16, amphoteric detergents). Following acellularization, hematoxylin-eosin staining and scanning electron microscopy demonstrated that the effect of acellularization via the modified method was similar to the traditional Sondell method. However, effects of demyelination and nerve fiber tube integrity were superior to the traditional Sondell method. Biomechanical testing showed that peripheral nerve graft treated using the chemical method resulted in decreased biomechanical properties (ultimate load, ultimate stress, ultimate strain, and mechanical work to fracture) compared with fresh nerves, but the differences had no statistical significance (P > 0.05). These results demonstrated no significant effect on biomechanical properties of nerves treated using the chemical method. In conclusion, nerve grafts treated via the modified method removed Schwann cells, preserved neural structures, and ensured biomechanical properties of the nerve graft, which could be more appropriate for implantation studies.

  8. Chemical functionalization of ceramic tile surfaces by silane coupling agents: polymer modified mortar adhesion mechanism implications

    Directory of Open Access Journals (Sweden)

    Alexandra Ancelmo Piscitelli Mansur

    2008-09-01

    Full Text Available Adhesion between tiles and mortars are crucial to the stability of ceramic tile systems. From the chemical point of view, weak forces such as van der Waals forces and hydrophilic interactions are expected to be developed preferably at the tiles and polymer modified Portland cement mortar interface. The main goal of this paper was to use organosilanes as primers to modify ceramic tile hydrophilic properties to improve adhesion between ceramic tiles and polymer modified mortars. Glass tile surfaces were treated with several silane derivatives bearing specific functionalities. Contact angle measurements and Fourier Transform Infrared Spectroscopy (FTIR were used for evaluating the chemical changes on the tile surface. In addition, pull-off tests were conducted to assess the effect on adhesion properties between tile and poly(ethylene-co-vinyl acetate, EVA, modified mortar. The bond strength results have clearly shown the improvement of adherence at the tile-polymer modified mortar interface, reflecting the overall balance of silane, cement and polymer interactions.

  9. Radiation-grafted, chemically modified membranes part I - Synthesis of a selective aluminum material

    Science.gov (United States)

    Bazante-Yamaguishi, Renata; Moura, Eduardo; Manzoli, José E.; Geraldo, Aurea B. C.

    2014-01-01

    Polymeric membranes were styrene grafted by irradiation methods and the obtained material was chemically modified to become aluminum selective. For this purpose, polymeric substrates of PVC (polyvinyl chloride) and PP (polypropylene) were styrene grafted mutually by gamma and electron beam irradiation. The modification process includes three basic reaction paths: Friedel-Crafts acylation, 2-methylanisole coupling and a final oxidation to achieve aluminum selectivity. Although this specific chemical modification in derivatives of polystyrene is not new, the new challenge is to obtain a selective material where original membrane characteristics (physical shape and mechanical resistance) are minimally conserved after such an aggressive treatment.

  10. Highly improved chromium (III uptake capacity in modified sugarcane bagasse using different chemical treatments

    Directory of Open Access Journals (Sweden)

    Vanessa Cristina Gonçalves Dos Santos

    2012-01-01

    Full Text Available The present paper focuses on improving chromium (III uptake capacity of sugarcane bagasse through its chemical modification with citric acid and/or sodium hydroxide. The chemical modifications were confirmed by infrared spectroscopy, with an evident peak observed at 1730 cm-1, attributed to carbonyl groups. Equilibrium was reached after 24 h, and the kinetics followed the pseudo-second-order model. The highest chromium (III maximum adsorption capacity (MAC value was found when using sugarcane bagasse modified with sodium hydroxide and citric acid (58.00 mg g-1 giving a MAC value about three times greater (20.34 mg g-1 than for raw sugarcane bagasse.

  11. Chemical modifiers in arsenic determination in biological materials by tungsten coil electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bruhn, C.G.; Huerta, V.N.; Neira, J.Y. [Departamento de Analisis Instrumental, Facultad de Farmacia, Universidad de Concepcion, P.O. Box 237, Concepcion (Chile)

    2004-01-01

    Palladium, iridium, and rhodium are evaluated as possible chemical modifiers in the determination of As in digest solutions of biological materials (human hair and clam) by tungsten coil electrothermal atomic absorption spectrophotometry (TCA-AAS). The modifier in solution was applied onto the coil and thermally pre-reduced; the pre-reduction conditions, the amount of modifier, and the thermal program were optimized. Palladium was not satisfactory, whereas Ir and Rh were effective modifiers and rendered better relative sensitivity for As by a factor of 1.4 and 1.9, respectively compared to the case without modifier. Upon optimization of thermal conditions for As in pre-reduced Ir (2.0 {mu}g) and Rh (2.0 {mu}g) modifiers and in the digest solutions of the study matrices, Rh (2.0 {mu}g) was more effective modifier and was selected as such. The mean within-day repeatability was 2.8% in consecutive measurements (25-100 {mu}g L{sup -1}) (3 cycles, each of n=6) and confirmed good short-term stability of the absorbance measurements. The mean reproducibility was 4.4% (n=20 in a 3-day period) and the detection limit (3{sigma}{sub blank}/slope) was 29 pg (n=15). The useful coil lifetime in Rh modifier was extended to 300-400 firings. Validation was by determination of As in the certified reference material (CRM) of ''Oyster tissue'' solution with a percentage relative error (E{sub rel}%) of 2% and percentage relative standard deviation (RSD%) of 3% (n=4), and by analytical recovery of As spiked in CRM of human hair [94{+-}8% (n=4)]. The methodology is simple, fast (sample readout frequency 21 h{sup -1}), reliable, of low cost, and was applied to the determination of As in hair samples of exposed and unexposed workers. (orig.)

  12. Influence of land use changes on soil physical, chemical and biological atributes in a family farming settlement in Eastern Amazon, Brazil

    Science.gov (United States)

    Cooper, Miguel; de Pierri Castilho, Selene Cristina; Camilo Bedano, José; Dominguez, Anahi; Fernanda Simões da Silva, Laura; Nascimento Delgado Oliveira, Mariana

    2014-05-01

    Soil knowledge and the changes in its attributes due to land use modifications in the Amazon region is important for decision making by family farmers. These farmers have to choose sustainable land use management practices for their survival in the region and, for soil and forest conservation. The study area is located in the Piranheira Praialta Agroextrativist Settlement Project in the county of Nova Ipixuna, Pará, Brazil. The objective of this research is to understand the relations between soil physical, chemical and biological attributes, and how these relations change with modifications in land use. This information is important for defining best management practices for family farming in the region. Two toposequences were chosen, one under native forest and the other under pasture. 40 cm pits were opened with five replicates in three landscape positions (upslope, midslope and downslope). Sampling periods were July/2012 (dry season); January/2013 (beginning of rainy season) and march/2013 (rainy season). Samples were taken for soil particle size analysis, bulk density, particle density, moisture, porosity, water retention, chemical, litter dry matter and macrofauna analysis. Statistical analysis techniques were performed uni and multivariate. No significant differences were observed in the particle size distribution of the studied soils. The soils presented sandy surface horizons with an increase of clay in depth in both land use systems. Soil bulk density values were higher in the surface horizons and, in general, in the pasture toposequence. Differences were also observed in the soil moisture content and litter dry matter which were higher under the native forest, and in the pH and organic matter values which were higher in the pasture. Higher water retention capacity was observed in the surface horizons of the forest when compared to the pasture, corroborating the higher values of macroporosity observed in the forest soils. Due to higher moisture content

  13. Research on the chemical mechanism in the polyacrylate latex modified cement system

    International Nuclear Information System (INIS)

    In this paper, the chemical mechanism in the polyacrylate latex modified cement system was investigated by Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), gel permeation chromatography (GPC) and compact pH meter. All results have shown that the chemical reactions in the polyacrylate modified system can be divided into three stages. The hydration reactions of cement can produce large amounts of Ca(OH)2 (calcium hydroxide) and lead the whole system to be alkali-rich and exothermic at the first stage. Subsequently, this environment can do great contributions to the hydrolysis of ester groups in the polyacrylate chains, resulting in the formation of carboxyl groups at the second stage. At the third stage, the final crosslinked network structure of the product was obtained by the reaction between the carboxyl groups in the polyacrylate latex chains and Ca(OH)2

  14. Research on the chemical mechanism in the polyacrylate latex modified cement system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Min [The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education and Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi' an 710072 (China); Wang, Rumin, E-mail: wangmin19@mail.nwpu.edu.cn [The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education and Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi' an 710072 (China); Zheng, Shuirong [The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education and Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi' an 710072 (China); Northwestern Polytechnical University–East China University of Science and Technology Combined Research Institute of New High Speed Railway Materials (China); Farhan, Shameel; Yao, Hao; Jiang, Hao [The Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education and Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi' an 710072 (China)

    2015-10-15

    In this paper, the chemical mechanism in the polyacrylate latex modified cement system was investigated by Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS), gel permeation chromatography (GPC) and compact pH meter. All results have shown that the chemical reactions in the polyacrylate modified system can be divided into three stages. The hydration reactions of cement can produce large amounts of Ca(OH){sub 2} (calcium hydroxide) and lead the whole system to be alkali-rich and exothermic at the first stage. Subsequently, this environment can do great contributions to the hydrolysis of ester groups in the polyacrylate chains, resulting in the formation of carboxyl groups at the second stage. At the third stage, the final crosslinked network structure of the product was obtained by the reaction between the carboxyl groups in the polyacrylate latex chains and Ca(OH){sub 2}.

  15. Sorption and desorption of Fe(III) on natural and chemically modified zeolite

    International Nuclear Information System (INIS)

    The Fe(III) uptake from aqueous solutions by natural and chemically modified zeolites was investigated using a gradual radioexchange method and AAS technique. The leachability of Fe(III) from loaded zeolites was studied too. The Fe-uptake reached the value of 60 mg x g-1 for the zeolite chemically treated with 6 mol x l-1 solution of NaOH and it is more than twelve times higher than that of the raw zeolite. The leachability of the loaded zeolite samples in water and alkaline solution was up 5%. The leachability of the same zeolites in acid solution depended on the concentration of modifying solution. The leachability at pH = 2.6 in the range 2-20% at pH = 1.9 was many times higher. The results of the radioexchange and AAS methods were compared. (author)

  16. Chemically Modified Ordered Mesoporous Carbon/Polyaniline Composites for Electrochemical Capacitors

    Institute of Scientific and Technical Information of China (English)

    KONG Ling-bin; ZHANG Jing; CAI Jian-jun; YANG Zhen-sheng; LUO Yong-chun; KANG Long

    2011-01-01

    Chemically modified ordered mesoporous carbon CMK-3 materials were prepared by means of an easy wet-oxidative method in 2 mol/L nitric acid aqueous solution. A large amount of oxygen-containing functional groups were introduced onto the CMK-3 surface. Modified CMK-3(m-CMK-3) and aniline monomer were polymerized via an in situ chemical oxidative polymerization method. Morphological characterizations of m-CMK-3/PANI (polyaniline) composites were carried out via field emission scanning electron microscopy(SEM). Their electrochemical properties were investigated with cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The m-CMK-3/PANI composites have excellent properties in capacitance, and the highest specific capacitance(SC) value was up to 489 F/g, suggesting their potential application in the electrode material for electrochemical capacitors.

  17. Adsorption and desorption of Cr(III) on natural and chemically modified Slovak zeolites

    International Nuclear Information System (INIS)

    Natural and chemically modified zeolites from the Slovak Republic and Ukraine have been investigated as the adsorbents for the uptake of Cr(III). Model water solution of low radioactivity was used. The adsorption and desorption kinetics of chromium were established with the gradual radioexchange technique (tracer 51Cr) and flame AAS. The effect of the factors studied are examined and explained. The sorption coefficient μ, distribution coefficient KD, sorption capacity Γ, sorption rate S, and leachability of Cr were calculated in neutral, alkaline and acidic aqueous solutions. The sorption capacity of the modified zeolites was found to be greater by a factor of 2 to 16 than that of the unmodified ones depending on the modifying solution applied. The leachability of chromium from loaded zeolites into the neutral solution was negligible. The leachability into alkaline and acidic solutions increased over 40%. (author)

  18. Chemically modified STM tips for atomic-resolution imaging of ultrathin NaCI films

    Institute of Scientific and Technical Information of China (English)

    Zhe Li[1; Koen Schouteden[1; Violeta lancu[1; Ewald Janssens[1; Peter Lievens[1; Chris Van Haesendonck[1; Jorge I. Cerda[2

    2015-01-01

    Cl-functionalized scanning tunneling microscopy (STM) tips are fabricated by modifying a tungsten STM tip in situ on islands of ultrathin NaCI(100) films on Au(111) surfaces. The functionalized tips are used to achieve clear atomic- resolution imaging of NaCI(100) islands. In comparison with bare metal tips, the chemically modified tips yield drastically enhanced spatial resolution as well as contrast reversal in STM topographs, implying that Na atoms, rather than C1 atoms, are imaged as protrusions. STM simulations based on a Green's function formalism reveal that the experimentally observed contrast reversal in the STM topographs is due to the highly localized character of the Cl-pz states at the tip apex. An additional remarkable characteristic of the modified tips is that in dI/dV maps, a Na atom appears as a ring with a diameter that depends crucially on the tip-sample distance.

  19. Chemically modified heparins inhibit fibrinogen-bridged indirect adhesion between tumor cells and platelets

    OpenAIRE

    Zheng, Sheng; Liu, Yan; Jiao, Yang; Min WEI; ZENG, XIANLU

    2011-01-01

    The interaction between platelets and tumor cells is critical for the hematogenous metastasis of tumor cells. We recently reported that fibrinogen was capable of bridging and enhancing the interaction of platelets and tumor cells under conditions of physical shear force. In the present study, we aimed to detect the effects of 8 chemically modified heparins on the binding of fibrinogen to platelets or tumor cells using flow cytometry assays, as well as the fibrinogen-bridged adhesion of platel...

  20. Electrodeposition of platinum and silver into chemically modified microporous silicon electrodes

    OpenAIRE

    Koda, Ryo; Fukami, Kazuhiro; Sakka, Tetsuo; Ogata, Yukio H.

    2012-01-01

    Electrodeposition of platinum and silver into hydrophobic and hydrophilic microporous silicon layers was investigated using chemically modified microporous silicon electrodes. Hydrophobic microporous silicon enhanced the electrodeposition of platinum in the porous layer. Meanwhile, hydrophilic one showed that platinum was hardly deposited within the porous layer, and a film of platinum on the top of the porous layer was observed. On the other hand, the electrodeposition of silver showed simil...

  1. Chemically modified bitumens with enhanced rheology and adhesion properties to siliceous aggregates

    OpenAIRE

    Cuadri Vega, Antonio Abad; Partal López, Pedro; Ahmad, Naveed; Grenfell, James; Airey, Gordon

    2015-01-01

    Moisture damage is one of the major premature failures that worsens the performance and shortens service life of pavements. This research assesses the effect that two chemical modifiers (thiourea and an isocyanate-functionalized castor oil prepolymer) exerts on the bitumen rheology and on the resistance to potential moisture damage of asphalt mixtures based on siliceous aggregates. Both thiourea and the isocyanate-based prepolymer improve the viscous and viscoelastic behaviours of bitumen at ...

  2. High-performance NO2 sensors based on chemically modified graphene.

    Science.gov (United States)

    Yuan, Wenjing; Liu, Anran; Huang, Liang; Li, Chun; Shi, Gaoquan

    2013-02-01

    Covalently grafting reduced graphene oxide (rGO) sheets with sulfophenyl or ethylenediamine groups can produce chemically modified graphene (CMG) for fabricating high-performance gas sensors. The NO(2) sensors based on these CMGs exhibit sensitivities 4 to 16 times higher than that of a sensor based on rGO. They also show excellent selectivity and repeatability without the aid of UV-light or thermal treatment. PMID:23139053

  3. Programming Amazon EC2

    CERN Document Server

    Vliet, Jurg

    2011-01-01

    If you plan to use Amazon Web Services to run applications in the cloud, the end-to-end approach in this book will save you needless trial and error. You'll find practical guidelines for designing and building applications with Amazon Elastic Compute Cloud (EC2) and a host of supporting AWS tools, with a focus on critical issues such as load balancing, monitoring, and automation. How do you move an existing application to AWS, or design your application so that it scales effectively? How much storage will you require? Programming Amazon EC2 not only helps you get started, it will also keep y

  4. Effect of chemical heterogeneity on photoluminescence of graphite oxide treated with S-/N-containing modifiers

    Science.gov (United States)

    Ebrahim, Amani M.; Rodríguez-Castellón, Enrique; Montenegro, José María; Bandosz, Teresa J.

    2015-03-01

    Graphite oxide (GO) obtained using Hummers method was modified by hydrothermal treatment either with sulfanilic acid or polystyrene (3-ammonium) sulfonate at 100 °C or 85 °C, respectively. Both modifiers contain sulfur in the oxidized forms and nitrogen in the reduced forms. The materials were characterized using FTIR, XPS, thermal analysis, potentiometric titration and SEM. Their photoluminescent properties and their alteration with an addition of Ag+ were also measured. As a result of these modifications nitrogen was introduced to the graphene layers as amines, imides, amides, and sulfur as sulfones and sulfonic acids. Moreover, the presence of polyaniline was detected. This significantly affected the polarity, acid-base character, and conductivity of the materials. Apparently carboxylic groups of GO were involved in the surface reactions. The modified GOs lost their layered structure and the modifications resulted in the high degree of structural and chemical heterogeneity. Photoluminescence in visible light was recorded and linked to the presence of heteroatoms. For the polystyrene (3-ammonium) sulfonate modified sample addition of Ag+ quenched the photoluminescence at low wavelength showing sensitivity as a possible optical detector. No apparent effect was found for the sulfanilic acid modified sample.

  5. Chemically modified biochar produced from conocarpus waste increases NO3 removal from aqueous solutions.

    Science.gov (United States)

    Usman, Adel R A; Ahmad, Mahtab; El-Mahrouky, Mohamed; Al-Omran, Abdulrasoul; Ok, Yong Sik; Sallam, Abdelazeem Sh; El-Naggar, Ahmed H; Al-Wabel, Mohammad I

    2016-04-01

    Biochar has emerged as a universal sorbent for the removal of contaminants from water and soil. However, its efficiency is lower than that of commercially available sorbents. Engineering biochar by chemical modification may improve its sorption efficiency. In this study, conocarpus green waste was chemically modified with magnesium and iron oxides and then subjected to thermal pyrolysis to produce biochar. These chemically modified biochars were tested for NO3 removal efficiency from aqueous solutions in batch sorption isothermal and kinetic experiments. The results revealed that MgO-biochar outperformed other biochars with a maximum NO3 sorption capacity of 45.36 mmol kg(-1) predicted by the Langmuir sorption model. The kinetics data were well described by the Type 1 pseudo-second-order model, indicating chemisorption as the dominating mechanism of NO3 sorption onto biochars. Greater efficiency of MgO-biochar was related to its high specific surface area (391.8 m(2) g(-1)) and formation of strong ionic complexes with NO3. At an initial pH of 2, more than 89 % NO3 removal efficiency was observed for all of the biochars. We conclude that chemical modification can alter the surface chemistry of biochar, thereby leading to enhanced sorption capacity compared with simple biochar. PMID:26100325

  6. Transfer of Chemically Modified Graphene with Retention of Functionality for Surface Engineering.

    Science.gov (United States)

    Whitener, Keith E; Lee, Woo-Kyung; Bassim, Nabil D; Stroud, Rhonda M; Robinson, Jeremy T; Sheehan, Paul E

    2016-02-10

    Single-layer graphene chemically reduced by the Birch process delaminates from a Si/SiOx substrate when exposed to an ethanol/water mixture, enabling transfer of chemically functionalized graphene to arbitrary substrates such as metals, dielectrics, and polymers. Unlike in previous reports, the graphene retains hydrogen, methyl, and aryl functional groups during the transfer process. This enables one to functionalize the receiving substrate with the properties of the chemically modified graphene (CMG). For instance, magnetic force microscopy shows that the previously reported magnetic properties of partially hydrogenated graphene remain after transfer. We also transfer hydrogenated graphene from its copper growth substrate to a Si/SiOx wafer and thermally dehydrogenate it to demonstrate a polymer- and etchant-free graphene transfer for potential use in transmission electron microscopy. Finally, we show that the Birch reduction facilitates delamination of CMG by weakening van der Waals forces between graphene and its substrate. PMID:26784372

  7. Self-assembled monolayer-modified block copolymers for chemical surface nanopatterning

    International Nuclear Information System (INIS)

    Research highlights: → Self-organizing PS-b-PMMA creates striped nanostructure scaffolds. → These striped nanostructures can be selectively metalized and modified using light. → Metalized stripes can be decorated with SAMs to create functional substrates. → Nanostructured surfaces thus prepared exhibit controlled wetting and recognition. - Abstract: Thin-film poly(styrene-block-methyl methacrylate) diblock copolymer (PS-b-PMMA) is used to create chemically patterned surfaces via metal deposition combined with self-assembled monolayers (SAMs) and UV exposure. We use this method to produce surfaces that are chemically striped on the scale of a few tens of nanometers. Atomic force and transmission electron microscopies are used to verify the spatially localized organization of materials, and contact angle measurements confirm the chemical tunability of these scaffolds. These surfaces may be used for arraying nanoscale objects, such as nanoparticles or biological species, or for electronic, magnetic memory or photovoltaic applications.

  8. Sensory and rheological properties of transgenically and chemically modified starch ingredients as evaluated in a food product model

    DEFF Research Database (Denmark)

    Ahmt, T.; Wischmann, Bente; Blennow, A.;

    2004-01-01

    gels with a higher tendency to retrograde and a low freeze/thaw stability as compared to starches with shorter amylopectin chains and lower phosphorous content. The textural properties of the food product model prepared from genetically and chemically modified starches were characterised by sensory......Starches derived from five genetically modified potato lines, two chemically modified potato starches and two native starches from potato and maize were subjected to physical and chemical analyses and their functionality evaluated in a milk-based food product model. The transgenic starches were...

  9. Chemical composition and corrosion protection of silane films modified with CeO2 nanoparticles

    International Nuclear Information System (INIS)

    The present work aims at understanding the role of CeO2 nanoparticles (with and without activation in cerium(III) solutions) used as fillers for hybrid silane coatings applied on galvanized steel substrates. The work reports the improved corrosion protection performance of the modified silane films and discusses the chemistry of the cerium-activated nanoparticles, the mechanisms involved in the formation of the surface coatings and its corrosion inhibition ability. The anti-corrosion performance was investigated using electrochemical impedance spectroscopy (EIS), the scanning vibrating electrode technique (SVET) and d.c. potentiodynamic polarization. The chemical composition of silanised nanoparticles and the chemical changes of the silane solutions due to the presence of additives were studied using X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance spectroscopy (NMR), respectively. The NMR and XPS data revealed that the modified silane solutions and respective coatings have enhanced cross-linking and that silane-cerium bonds are likely to occur. Electrochemical impedance spectroscopy showed that the modified coatings have improved barrier properties and the SVET measurements highlight the corrosion inhibition effect of ceria nanoparticles activated with Ce(III) ions. Potentiodynamic polarization curves demonstrate an enhanced passive domain for zinc, in the presence of nanoparticles, in solutions simulating the cathodic environment.

  10. Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers

    Science.gov (United States)

    Rodríguez-Uicab, O.; Avilés, F.; Gonzalez-Chi, P. I.; Canché-Escamilla, G.; Duarte-Aranda, S.; Yazdani-Pedram, M.; Toro, P.; Gamboa, F.; Mazo, M. A.; Nistal, A.; Rubio, J.

    2016-11-01

    Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating ("sizing"), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

  11. Evaluation of batch biosorption of chromium (vi) from aqueous solution by chemically modified polyalthia longifolia leaves

    International Nuclear Information System (INIS)

    Removal of toxic metals from surface water is a significant matter of concern. Biosorption is emerging as an economical and eco friendly methodology for the removal of toxic chemicals from waste water. Optimization of operating conditions has a large impact on the efficiency of this process. Simple untreated and chemically modified Polyalthia longifolia leaves were used to study biosorption of Cr (VI) from aqueous media within various experimental conditions and their efficiency of biosorption were compared. The effects of different conditions, such as contact time of solution with bio sorbent, temperature, pH, biosorbent dose and agitation speed for the removal of Cr (VI) were studied. It is found that acid treated Polyalthia longifolia leaves have greater biosorption capacity as compared to untreated and base treated leaves. Langmuir and Freundlich isotherms were also applied to evaluate maximum biosorption capacity of simple untreated and chemically modified Polyalthia longifolia leaves for Cr (VI). This research work is of great importance in regard of practical waste water treatment by biosorption. (author)

  12. The Use of Aryl Hydrazide Linkers for the Solid Phase Synthesis of Chemically Modified Peptides

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Y; Mitchell, A R; Camarero, J A

    2006-11-03

    Since Merrifield introduced the concept of solid phase synthesis in 1963 for the rapid preparation of peptides, a large variety of different supports and resin-linkers have been developed that improve the efficiency of peptide assembly and expand the myriad of synthetically feasible peptides. The aryl hydrazide is one of the most useful resin-linkers for the synthesis of chemically modified peptides. This linker is completely stable during Boc- and Fmoc-based solid phase synthesis and yet it can be cleaved under very mild oxidative conditions. The present article reviews the use of this valuable linker for the rapid and efficient synthesis of C-terminal modified peptides, head-to-tail cyclic peptides and lipidated peptides.

  13. Silencing of Inducible Immunoproteasome Subunit Expression by Chemically Modified siRNA and shRNA.

    Science.gov (United States)

    Gvozdeva, Olga V; Prassolov, Vladimir S; Zenkova, Marina A; Vlassov, Valentin V; Chernolovskaya, Elena L

    2016-08-01

    Overexpression of inducible subunits of immunoproteasome is related to pathogenesis of some chronic diseases. Specific inhibition of the immunosubunits may be used for the treatment of these diseases and RNA interference is one of the potent methods used in this area. We designed 2'-O-methyl modified siRNAs with selectively protected nuclease-sensitive sites, which efficiently silence LMP2, LMP7, and MECL-1 genes expression. To provide stable long-lasting inhibition of target genes, short-hairpin RNAs (shRNA) expressed by lentiviral vectors were constructed. Our results demonstrated that chemically modified siRNAs inhibited the expression of target genes with similar efficiency or with efficiency exceeding that of corresponding shRNAs and provide silencing effect for 5 days.

  14. Regional and large-scale patterns in Amazon forest structure and function are mediated by variations in soil physical and chemical properties

    Directory of Open Access Journals (Sweden)

    C. A. Quesada

    2009-04-01

    Full Text Available Forest structure and dynamics have been noted to vary across the Amazon Basin in an east-west gradient in a pattern which coincides with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates.

    To test this hypothesis and assess the importance of edaphic properties in affect forest structure and dynamics, soil and plant samples were collected in a total of 59 different forest plots across the Amazon Basin. Samples were analysed for exchangeable cations, C, N, pH with various P fractions also determined. Physical properties were also examined and an index of soil physical quality developed.

    Overall, forest structure and dynamics were found to be strongly and quantitatively related to edaphic conditions. Tree turnover rates emerged to be mostly influenced by soil physical properties whereas forest growth rates were mainly related to a measure of available soil phosphorus, although also dependent on rainfall amount and distribution. On the other hand, large scale variations in forest biomass could not be explained by any of the edaphic properties measured, nor by variation in climate.

    A new hypothesis of self-maintaining forest dynamic feedback mechanisms initiated by edaphic conditions is proposed. It is further suggested that this is a major factor determining forest disturbance levels, species composition and forest productivity on a Basin wide scale.

  15. Size-dependent mobility of gold nano-clusters during growth on chemically modified graphene

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Gavin R., E-mail: gavin.bell@warwick.ac.uk; Dawson, Peter M.; Pandey, Priyanka A.; Wilson, Neil R. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Mulheran, Paul A. [Department of Chemical and Process Engineering, University of Strathclyde, James Weir Building, 75 Montrose St., Glasgow G1 1XJ (United Kingdom)

    2014-01-01

    Gold nano-clusters were grown on chemically modified graphene by direct sputter deposition. Transmission electron microscopy of the nano-clusters on these electron-transparent substrates reveals an unusual bimodal island size distribution (ISD). A kinetic Monte Carlo model of growth incorporating a size-dependent cluster mobility rule uniquely reproduces the bimodal ISD, providing strong evidence for the mobility of large clusters during surface growth. The cluster mobility exponent of −5/3 is consistent with cluster motion via one-dimensional diffusion of gold atoms around the edges of the nano-clusters.

  16. Fast and simple purification of chemically modified hammerhead ribozymes using a lipophilic capture tag.

    OpenAIRE

    Sproat, B S; Rupp, T; Menhardt, N; Keane, D.; Beijer, B

    1999-01-01

    A new type of 5'-lipophilic capture tag is described, enabling the facile reverse phase HPLC purification of chemically modified hammerhead ribozymes (oligozymes) whilst still carrying the 2'-O-tert.-butyldimethylsilyl protection of the essential riboses. In its most convenient form, the capture tag consists of a simple diol, such as hexan-1,6-diol, which at one end is attached via a silyl residue to a highly lipophilic entity such as tocopherol (vitamin E) or cholesterol, and the other end i...

  17. Highly dispersed Pd nanoparticles on chemically modified graphene with aminophenyl groups for formic acid oxidation

    Institute of Scientific and Technical Information of China (English)

    Yang Su-Dong; Shen Cheng-Min; Tong Hao; He Wei; Zhang Xiao-Gang; Gao Hong-Jun

    2011-01-01

    A novel electrode material based on chemically modified graphene (CMG) with aminophenyl groups is covalently functionalized by a nucleophilic ring-opening reaction between the epoxy groups of graphene oxide and the aminophenyl groups of p-phenylenediamine.Palladium nanoparticles with an average diameter of 4.2 nm are deposited on the CMG by a liquid-phase borohydride reduction.The electrocatalytic activity and stability of the Pd/CMG composite towards formic acid oxidation are found to be higher than those of reduced graphene oxide and commercial carbon materials such as Vulcan XC-72 supported Pd electrocatalysts.

  18. Modified Augmented Lagrange Multiplier Methods for Large-Scale Chemical Process Optimization

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Chemical process optimization can be described as large-scale nonlinear constrained minimization. The modified augmented Lagrange multiplier methods (MALMM) for large-scale nonlinear constrained minimization are studied in this paper. The Lagrange function contains the penalty terms on equality and inequality constraints and the methods can be applied to solve a series of bound constrained sub-problems instead of a series of unconstrained sub-problems. The steps of the methods are examined in full detail. Numerical experiments are made for a variety of problems, from small to very large-scale, which show the stability and effectiveness of the methods in large-scale problems.

  19. Size-dependent mobility of gold nano-clusters during growth on chemically modified graphene

    Directory of Open Access Journals (Sweden)

    Gavin R. Bell

    2014-01-01

    Full Text Available Gold nano-clusters were grown on chemically modified graphene by direct sputter deposition. Transmission electron microscopy of the nano-clusters on these electron-transparent substrates reveals an unusual bimodal island size distribution (ISD. A kinetic Monte Carlo model of growth incorporating a size-dependent cluster mobility rule uniquely reproduces the bimodal ISD, providing strong evidence for the mobility of large clusters during surface growth. The cluster mobility exponent of −5/3 is consistent with cluster motion via one-dimensional diffusion of gold atoms around the edges of the nano-clusters.

  20. Peroxide-modified titanium dioxide: a chemical analog of putative Martian soil oxidants

    Science.gov (United States)

    Quinn, R. C.; Zent, A. P.

    1999-01-01

    Hydrogen peroxide chemisorbed on titanium dioxide (peroxide-modified titanium dioxide) is investigated as a chemical analog to the putative soil oxidants responsible for the chemical reactivity seen in the Viking biology experiments. When peroxide-modified titanium dioxide (anatase) was exposed to a solution similar to the Viking labeled release (LR) experiment organic medium, CO2 gas was released into the sample cell headspace. Storage of these samples at 10 degrees C for 48 hr prior to exposure to organics resulted in a positive response while storage for 7 days did not. In the Viking LR experiment, storage of the Martian surface samples for 2 sols (approximately 49 hr) resulted in a positive response while storage for 141 sols essentially eliminated the initial rapid release of CO2. Heating the peroxide-modified titanium dioxide to 50 degrees C prior to exposure to organics resulted in a negative response. This is similar to, but not identical to, the Viking samples where heating to approximately 46 degrees C diminished the response by 54-80% and heating to 51.5 apparently eliminated the response. When exposed to water vapor, the peroxide-modified titanium dioxide samples release O2 in a manner similar to the release seen in the Viking gas exchange experiment (GEx). Reactivity is retained upon heating at 50 degrees C for three hours, distinguishing this active agent from the one responsible for the release of CO2 from aqueous organics. The release of CO2 by the peroxide-modified titanium dioxide is attributed to the decomposition of organics by outer-sphere peroxide complexes associated with surface hydroxyl groups, while the release of O2 upon humidification is attributed to more stable inner-sphere peroxide complexes associated with Ti4+ cations. Heating the peroxide-modified titanium dioxide to 145 degrees C inhibited the release of O2, while in the Viking experiments heating to this temperature diminished but did not eliminated the response. Although the

  1. A Mechanistic Study of Chemically Modified Inorganic Membranes for Gas and Liquid Separations

    Energy Technology Data Exchange (ETDEWEB)

    Way, J Douglas

    2011-01-21

    This final report will summarize the progress made during the period August 1, 1993 - October 31, 2010 with support from DOE grant number DE-FG03-93ER14363. The objectives of the research have been to investigate the transport mechanisms in micro- and mesoporous, metal oxide membranes and to examine the relationship between the microstructure of the membrane, the membrane surface chemistry, and the separation performance of the membrane. Examples of the membrane materials under investigation are the microporous silica hollow fiber membrane manufactured by PPG Industries, chemically modified mesoporous oxide membranes, and polymer membranes containing microporous oxides (mixed matrix membranes). Analytical techniques such as NMR, FTIR and Raman spectroscopy, thermal analysis, and gas adsorption were used to investigate membrane microstructure and to probe the chemical interactions occurring at the gas-membrane interface.

  2. Two dimensional solid state NMR methods applied to whole coals and chemically modified coals

    Energy Technology Data Exchange (ETDEWEB)

    Zilm, K.W.; Webb, G.G.; Millar, J.M.

    1987-04-01

    Two dimensional NMR methods have been shown to provide a much finer accounting of the functional types present in coals than by CPMAS spectroscopy alone. The ADIPSHIFT method has been shown to be at least as quantitative as CPMAS both in theory and experimentally. The method gives reliable distributions of carbons with differing multiplicities which is useful in identifying different functionalities that overlap in chemical shift. Recent studies of a model system indicate that the connectivity of the different groups in chemically modified coals should be obtainable from solid state COSY and NOESY experiments. This type of information will provide a very accurate picture of the structure of the alkylated sites and the substitution patterns surrounding them.

  3. Free-radical-promoted conversion of graphite oxide into chemically modified graphene.

    Science.gov (United States)

    Chai, Na-Na; Zeng, Jing; Zhou, Kai-Ge; Xie, Yu-Long; Wang, Hang-Xing; Zhang, Hao-Li; Xu, Chen; Zhu, Ji-Xin; Yan, Qing-Yu

    2013-05-01

    The preparation of chemically modified graphene (CMG) generally involves the reduction of graphite oxide (GO) by using various reducing reagents. Herein, we report a free-radical-promoted synthesis of CMG, which does not require any conventional reductant. We demonstrated that the phenyl free radical can efficiently promote the conversion of GO into CMG under mild conditions and produces phenyl-functionalized CMG. This pseudo-"reduction" process is attributed to a free-radical-mediated elimination of the surface-attached oxygen-containing functionalities. This work illustrates a new strategy for preparing CMG that is alternative to the conventional means of chemical reduction. Furthermore, the phenyl-functionalized graphene shows an excellent performance as an electrode material for lithium-battery applications.

  4. Facile Synthesis of Mono-Dispersed Polystyrene (PS/Ag Composite Microspheres via Modified Chemical Reduction

    Directory of Open Access Journals (Sweden)

    Wen Zhu

    2013-12-01

    Full Text Available A modified method based on in situ chemical reduction was developed to prepare mono-dispersed polystyrene/silver (PS/Ag composite microspheres. In this approach; mono-dispersed PS microspheres were synthesized through dispersion polymerization using poly-vinylpyrrolidone (PVP as a dispersant at first. Then, poly-dopamine (PDA was fabricated to functionally modify the surfaces of PS microspheres. With the addition of [Ag(NH32]+ to the PS dispersion, [Ag(NH32]+ complex ions were absorbed and reduced to silver nanoparticles on the surfaces of PS-PDA microspheres to form PS/Ag composite microspheres. PVP acted both as a solvent of the metallic precursor and as a reducing agent. PDA also acted both as a chemical protocol to immobilize the silver nanoparticles at the PS surface and as a reducing agent. Therefore, no additional reducing agents were needed. The resulting composite microspheres were characterized by TEM, field emission scanning electron microscopy (FESEM, energy-dispersive X-ray spectroscopy (EDS, XRD, UV-Vis and surface-enhanced Raman spectroscopy (SERS. The results showed that Ag nanoparticles (NPs were homogeneously immobilized onto the PS microspheres’ surface in the presence of PDA and PVP. PS/Ag composite microspheres were well formed with a uniform and compact shell layer and were adjustable in terms of their optical property.

  5. Chemically modified inulin microparticles serving dual function as a protein antigen delivery vehicle and immunostimulatory adjuvant.

    Science.gov (United States)

    Gallovic, Matthew D; Montjoy, Douglas G; Collier, Michael A; Do, Clement; Wyslouzil, Barbara E; Bachelder, Eric M; Ainslie, Kristy M

    2016-03-01

    To develop a new subunit vaccine adjuvant, we chemically modified a naturally-occurring, immunostimulatory inulin polysaccharide to produce an acid-sensitive biopolymer (acetalated inulin, Ace-IN). Various hydrophobic Ace-IN polymers were formed into microparticles (MPs) by oil-in-water emulsions followed by solvent evaporation These Ace-IN MPs possessed tunable degradation characteristics that, unlike polyesters used in FDA-approved microparticulate formulations, had only pH-neutral hydrolytic byproducts. Macrophages were passively targeted with cytocompatible Ace-IN MPs. TNF-α production by macrophages treated with Ace-IN MPs could be altered by adjusting the polymers' chemistry. Mice immunized with Ace-IN MPs encapsulating a model ovalbumin (OVA) antigen showed higher production of anti-OVA IgG antibody levels relative to soluble antigen. The antibody titers were also comparable to an alum-based formulation. This proof-of-concept establishes the potential for chemically-modified inulin MPs to simultaneously enable dual functionality as a stimuli-controlled antigen delivery vehicle and immunostimulatory adjuvant.

  6. Determination of bisphenol A in food-simulating liquids using LCED with a chemically modified electrode.

    Science.gov (United States)

    D'Antuono, A; Dall'Orto, V C; Lo Balbo, A; Sobral, S; Rezzano, I

    2001-03-01

    Liquid chromatography with electrochemical detector (LC-ED), using a chemically modified electrode coated with a metalloporphyrin film, is reported for determination of bisphenol A (BPA) migration from polycarbonate baby bottles. The extraction process of the samples was performed according to regulations of the Southern Common Market (MERCOSUR), where certain food-simulating liquids [(A) distilled water, (B) acetic acid 3% V/V in distilled water, and (C) ethanol 15% V/V in distilled water] are defined along with controlled time and temperature conditions. The baseline obtained using the naked electrode showed a considerable drift which increased the detection limit. This effect was suppressed with the chemically modified electrode. A linear range up to 450 ppb along with a detection limit of 20 ppb for the amperometric detection technique was observed. The procedure described herein allowed lowering the detection limit of the method to 0.2 ppb. The value found for BPA in the food-simulating liquid is 1.2 ppb, which is below the tolerance limit for specific migration (4.8 ppm).

  7. Aqueous dispersions of few-layer-thick chemically modified magnesium diboride nanosheets by ultrasonication assisted exfoliation

    Science.gov (United States)

    Das, Saroj Kumar; Bedar, Amita; Kannan, Aadithya; Jasuja, Kabeer

    2015-01-01

    The discovery of graphene has led to a rising interest in seeking quasi two-dimensional allotropes of several elements and inorganic compounds. Boron, carbon’s neighbour in the periodic table, presents a curious case in its ability to be structured as graphene. Although it cannot independently constitute a honeycomb planar structure, it forms a graphenic arrangement in association with electron-donor elements. This is exemplified in magnesium diboride (MgB2): an inorganic layered compound comprising boron honeycomb planes alternated by Mg atoms. Till date, MgB2 has been primarily researched for its superconducting properties; it hasn’t been explored for the possibility of its exfoliation. Here we show that ultrasonication of MgB2 in water results in its exfoliation to yield few-layer-thick Mg-deficient hydroxyl-functionalized nanosheets. The hydroxyl groups enable an electrostatically stabilized aqueous dispersion and create a heterogeneity leading to an excitation wavelength dependent photoluminescence. These chemically modified MgB2 nanosheets exhibit an extremely small absorption coefficient of 2.9 ml mg−1 cm−1 compared to graphene and its analogs. This ability to exfoliate MgB2 to yield nanosheets with a chemically modified lattice and properties distinct from the parent material presents a fundamentally new perspective to the science of MgB2 and forms a first foundational step towards exfoliating metal borides. PMID:26041686

  8. Chemically and biologically synthesized CPP-modified gelonin for enhanced anti-tumor activity.

    Science.gov (United States)

    Shin, Meong Cheol; Zhang, Jian; David, Allan E; Trommer, Wolfgang E; Kwon, Young Min; Min, Kyoung Ah; Kim, Jin H; Yang, Victor C

    2013-11-28

    The ineffectiveness of small molecule drugs against cancer has generated significant interest in more potent macromolecular agents. Gelonin, a plant-derived toxin that inhibits protein translation, has attracted much attention in this regard. Due to its inability to internalize into cells, however, gelonin exerts only limited tumoricidal effect. To overcome this cell membrane barrier, we modified gelonin, via both chemical conjugation and genetic recombination methods, with low molecular weight protamine (LMWP), a cell-penetrating peptide (CPP) which was shown to efficiently ferry various cargoes into cells. Results confirmed that gelonin-LMWP chemical conjugate (cG-L) and recombinant gelonin-LMWP chimera (rG-L) possessed N-glycosidase activity equivalent to that of unmodified recombinant gelonin (rGel); however, unlike rGel, both gelonin-LMWPs were able to internalize into cells. Cytotoxicity studies further demonstrated that cG-L and rG-L exhibited significantly improved tumoricidal effects, with IC50 values being 120-fold lower than that of rGel. Moreover, when tested against a CT26 s.c. xenograft tumor mouse model, significant inhibition of tumor growth was observed with rG-L doses as low as 2 μg/tumor, while no detectable therapeutic effects were seen with rGel at 10-fold higher doses. Overall, this study demonstrated the potential of utilizing CPP-modified gelonin as a highly potent anticancer drug to overcome limitations of current chemotherapeutic agents. PMID:23973813

  9. Dual-tracer method to estimate coral reef response to a plume of chemically modified seawater

    Science.gov (United States)

    Maclaren, J. K.; Caldeira, K.

    2013-12-01

    We present a new method, based on measurement of seawater samples, to estimate the response of a reef ecosystem to a plume of an additive (for example, a nutrient or other chemical). In the natural environment, where there may be natural variability in concentrations, it can be difficult to distinguish between changes in concentrations that would occur naturally and changes in concentrations that result from a chemical addition. Furthermore, in the unconfined natural environment, chemically modified water can mix with waters that have not been modified, making it difficult to distinguish between effects of dilution and effects of chemical fluxes or transformations. We present a dual-tracer method that extracts signals from observations that may be affected by both natural variability and dilution. In this dual-tracer method, a substance (in our example case, alkalinity) is added to the water in known proportion to a passive conservative tracer (in our example case, Rhodamine WT dye). The resulting plume of seawater is allowed to flow over the study site. Two transects are drawn across the plume at the front and back of the study site. If, in our example, alkalinity is plotted as a function of dye concentration for the front transect, the slope of the resulting mixing line is the ratio of alkalinity to dye in the added fluid. If a similar mixing line is measured and calculated for the back transect, the slope of this mixing line will indicate the amount of added alkalinity that remains in the water flowing out of the study site per unit of added dye. The ratio of the front and back slopes indicates the fraction of added alkalinity that was taken up by the reef. The method is demonstrated in an experiment performed on One Tree Reef (Queensland, Australia) aimed at showing that ocean acidification is already affecting coral reef growth. In an effort to chemically reverse some of the changes to seawater chemistry that have occurred over the past 200 years, we added

  10. The performance of chemically and physically modified local kaolinite in methanol dehydration to dimethyl ether

    Directory of Open Access Journals (Sweden)

    Sanaa M. Solyman

    2014-09-01

    Full Text Available The catalytic activity of modified natural kaolinite as a solid acid catalyst for dimethyl ether (DME preparation was investigated by following up the conversion% of methanol and the yield% of DME. Natural kaolinite (KN was treated chemically with H2O2 (KT followed by thermal treatment at 500 °C (KC and then mechano-chemically by ball milling with and without CaSO4 (KB-Ca and KB, respectively. These samples were characterized by XRD, FTIR, SEM, HRTEM, TGA and NH3-TPD techniques. The different techniques showed that the chemical treatment of kaolinite with H2O2 resulted in partial exfoliation/delamination of kaolinite, decreased the amount of acidic sites which is accompanied by increasing their strength. Calcination only decreased the acidic strength and slightly enlarged the particle size mostly due to heat effect. Ball milling resulted in multitude randomly-oriented crystals and increased the amount of acidic sites with the same strength of KT sample. CaSO4 mostly produced ordered monocrystalline kaolinite and created new acidic sites with slightly lower strength relative to KB. The catalytic activity and selectivity depend on the reaction temperature, the space velocity and the strength of acid sites. The most active sample is KB-Ca, which gives 84% DME due to its high amount and strength of acidic sites. The different modification methods resulted in 100% selectivity for DME.

  11. REMOVAL OF Pb (II FROM AQUEOUS SOLUTION WITH ORANGE SUB-PRODUCTS CHEMICALLY MODIFIED AS BIOSORBENT

    Directory of Open Access Journals (Sweden)

    João Valdir Tadioto Miranda De Souza,

    2012-02-01

    Full Text Available The effects of chemical modification of orange peel, bagasse, and a mixture of peel and bagasse for lead ion removal from aqueous medium were evaluated. The chemical modification of biomass was carried out with sodium hydroxide and citric acid to introduce carboxylate groups on the surface of the biomass. Infrared spectra confirmed the presence of carboxylate groups at 1735 cm-1. Adsorption isotherms performed by static adsorption experiments fitted very well to the linear Langmuir and Freundlich models. The experiments were carried out at pH 5 during 500 min of shaking time. Orange modified peel (O-MP presented the highest adsorption capacity (84.5 mg g-1, notably higher than other biosorbents described in the literature. The kinetic studies showed that the process obeyed a pseudo-second-order rate expression, thus indicating a strong interaction between the biosorbent and adsorbate. It was found that the chemical modifications of sorbents promoted an adsorption energetically more spontaneous, as indicated by negative values of Gibbs free energy. On the other hand, desorption studies showed low leaching of lead ions from the biosorbent, thus confirming the strong interaction of lead ions and the biosorbent. The satisfactory maximum adsorption capacity obtained and negligible cost of biosorbent makes the sub-products of orange a reliable natural material for the removal of lead ions from aqueous effluents.

  12. The Amazon and climate

    Science.gov (United States)

    Nobre, C. A.

    1984-01-01

    The climatologies of cloudiness and precipitation for the Amazon, are reviewed and the physical causes of some of the observed features and those which are not well known are explained. The atmospheric circulation over the Amazon is discussed on the large scale tropical circulations forced by deep diabatic heating sources. Weather deforestation which leads to a reduction in evapotranspiration into the atmosphere, and a reduction in precipitation and its implicated for the gobal climate is discussed. It is indicated that a large scale clearing of tropical rainforests there would be a reduction in rainfall which would have global effects on climate and weather both in the tropical and extratropical regions.

  13. Chemically modified and nanostructured porous silicon as a drug delivery material and device

    Science.gov (United States)

    Anglin, Emily Jessica

    This thesis describes the fabrication, chemical modification, drug release, and toxicity studies of nanostructured porous silicon for the purposes of developing a smart drug delivery device. The first chapter is an introductory chapter, presenting the chemical and physical properties of porous silicon, the concepts and issues of current drug delivery devices and materials, and how porous silicon can address the issues regarding localized and controlled drug therapies. The second chapter discusses chemical modifications of nanostructured porous Si for stabilizing the material in biologically relevant media while providing an extended release of a therapeutic in vitro. This chapter also demonstrates the utility of the porous silicon optical signatures for effectively monitoring drug release from the system and its applications for development of a self-reporting drug delivery device. In chapter three, the concept of providing a triggered release of a therapeutic from porous silicon microparticles through initiation by an external stimulus is demonstrated. The microparticles are chemically modified, and the release is enhanced by a short application of ultrasound to the particulate system. The effect of ultrasound on the drug release and particle size is discussed. Chapter four presents a new method for sustaining the release of a monoclonal antibody from the porous matrix of porous SiO2. The therapeutic is incorporated into the films through electrostatic adsorption and a slow release is observed in vitro. A new method of quantifying the extent of drug loading is monitored with interferometry. The last chapter of the thesis provides a basic in vivo toxicity study of various porous Si microparticles for intraocular applications. Three types of porous Si particles are fabricated and studied in a rabbit eye model. The toxicity studies were conducted by collaborators at the Shiley Eye Center, La Jolla, CA. This work, demonstrates the feasibility of developing a self

  14. Fabrication of Rare Earth-Doped Transparent Glass Ceramic Optical Fibers by Modified Chemical Vapor Deposition

    CERN Document Server

    Blanc, Wilfried; Nguyen, Luan; Bhaktha, S N B; Sebbah, Patrick; Pal, Bishnu P; Dussardier, Bernard

    2011-01-01

    Rare earth (RE) doped silica-based optical fibers with transparent glass ceramic (TGC) core was fabricated through the well-known modified chemical vapor deposition (MCVD) process without going through the commonly used stage of post-ceramming. The main characteristics of the RE-doped oxyde nanoparticles namely, their density and mean diameter in the fibers are dictated by the concentration of alkaline earth element used as phase separating agent. Magnesium and erbium co-doped fibers were fabricated. Optical transmission in term of loss due to scattering as well as some spectroscopic characteristics of the erbium ions was studied. For low Mg content, nano-scale particles could be grown with and relatively low scattering losses were obtained, whereas large Mg-content causes the growth of larger particles resulting in much higher loss. However in the latter case, certain interesting alteration of the spectroscopic properties of the erbium ions were observed. These initial studies should be useful in incorporati...

  15. A modified next reaction method for simulating chemical systems with time dependent propensities and delays.

    Science.gov (United States)

    Anderson, David F

    2007-12-01

    Chemical reaction systems with a low to moderate number of molecules are typically modeled as discrete jump Markov processes. These systems are oftentimes simulated with methods that produce statistically exact sample paths such as the Gillespie algorithm or the next reaction method. In this paper we make explicit use of the fact that the initiation times of the reactions can be represented as the firing times of independent, unit rate Poisson processes with internal times given by integrated propensity functions. Using this representation we derive a modified next reaction method and, in a way that achieves efficiency over existing approaches for exact simulation, extend it to systems with time dependent propensities as well as to systems with delays.

  16. Genome mining expands the chemical diversity of the cyanobactin family to include highly modified linear peptides.

    Science.gov (United States)

    Leikoski, Niina; Liu, Liwei; Jokela, Jouni; Wahlsten, Matti; Gugger, Muriel; Calteau, Alexandra; Permi, Perttu; Kerfeld, Cheryl A; Sivonen, Kaarina; Fewer, David P

    2013-08-22

    Ribosomal peptides are produced through the posttranslational modification of short precursor peptides. Cyanobactins are a growing family of cyclic ribosomal peptides produced by cyanobacteria. However, a broad systematic survey of the genetic capacity to produce cyanobactins is lacking. Here we report the identification of 31 cyanobactin gene clusters from 126 genomes of cyanobacteria. Genome mining suggested a complex evolutionary history defined by horizontal gene transfer and rapid diversification of precursor genes. Extensive chemical analyses demonstrated that some cyanobacteria produce short linear cyanobactins with a chain length ranging from three to five amino acids. The linear peptides were N-prenylated and O-methylated on the N and C termini, respectively, and named aeruginosamide and viridisamide. These findings broaden the structural diversity of the cyanobactin family to include highly modified linear peptides with rare posttranslational modifications. PMID:23911585

  17. Genetic and chemical modifiers of a CUG toxicity model in Drosophila.

    Directory of Open Access Journals (Sweden)

    Amparo Garcia-Lopez

    Full Text Available Non-coding CUG repeat expansions interfere with the activity of human Muscleblind-like (MBNL proteins contributing to myotonic dystrophy 1 (DM1. To understand this toxic RNA gain-of-function mechanism we developed a Drosophila model expressing 60 pure and 480 interrupted CUG repeats in the context of a non-translatable RNA. These flies reproduced aspects of the DM1 pathology, most notably nuclear accumulation of CUG transcripts, muscle degeneration, splicing misregulation, and diminished Muscleblind function in vivo. Reduced Muscleblind activity was evident from the sensitivity of CUG-induced phenotypes to a decrease in muscleblind genetic dosage and rescue by MBNL1 expression, and further supported by the co-localization of Muscleblind and CUG repeat RNA in ribonuclear foci. Targeted expression of CUG repeats to the developing eye and brain mushroom bodies was toxic leading to rough eyes and semilethality, respectively. These phenotypes were utilized to identify genetic and chemical modifiers of the CUG-induced toxicity. 15 genetic modifiers of the rough eye phenotype were isolated. These genes identify putative cellular processes unknown to be altered by CUG repeat RNA, and they include mRNA export factor Aly, apoptosis inhibitor Thread, chromatin remodelling factor Nurf-38, and extracellular matrix structural component Viking. Ten chemical compounds suppressed the semilethal phenotype. These compounds significantly improved viability of CUG expressing flies and included non-steroidal anti-inflammatory agents (ketoprofen, muscarinic, cholinergic and histamine receptor inhibitors (orphenadrine, and drugs that can affect sodium and calcium metabolism such as clenbuterol and spironolactone. These findings provide new insights into the DM1 phenotype, and suggest novel candidates for DM1 treatments.

  18. Amazon flood wave hydraulics

    Science.gov (United States)

    Trigg, Mark A.; Wilson, Matthew D.; Bates, Paul D.; Horritt, Matthew S.; Alsdorf, Douglas E.; Forsberg, Bruce R.; Vega, Maria C.

    2009-07-01

    SummaryA bathymetric survey of 575 km of the central Amazon River and one of its tributaries, the Purus, are combined with gauged data to characterise the Amazon flood wave, and for hydraulic modelling of the main channel for the period June 1995-March 1997 with the LISFLOOD-FP and HEC-RAS hydraulic models. Our investigations show that the Amazon flood wave is subcritical and diffusive in character and, due to shallow bed slopes, backwater conditions control significant reach lengths and are present for low and high water states. Comparison of the different models shows that it is necessary to include at least the diffusion term in any model, and the RMSE error in predicted water elevation at all cross sections introduced by ignoring the acceleration and advection terms is of the order of 0.02-0.03 m. The use of a wide rectangular channel approximation introduces an error of 0.10-0.15 m on the predicted water levels. Reducing the bathymetry to a simple bed slope and with mean cross section only, introduces an error in the order of 0.5 m. These results show that when compared to the mean annual amplitude of the Amazon flood wave of 11-12 m, water levels are relatively insensitive to the bathymetry of the channel model. The implication for remote sensing studies of the central Amazon channel, such as those proposed with the Surface Water and Ocean Topography mission (SWOT), is that even relatively crude assumptions regarding the channel bathymetry will be valid in order to derive discharge from water surface slope of the main channel, as long as the mean channel area is approximately correct.

  19. Kinetic and thermodynamic studies on biosorption of Cu(Ⅱ) by chemically modified orange peel

    Institute of Scientific and Technical Information of China (English)

    FENG Ning-chuan; GUO Xue-yi; LIANG Sha

    2009-01-01

    Cu(H) biosorption by orange peel that was chemically modified with sodium hydroxide and calcium chloride was investigated. The effects of temperature, contact time, initial concentration of metal ions and pH on the biosorption of Cu( II) ions were assessed. Thermodynamic parameters including change of free energy(△G~Θ), enthalpy (△H~Θ) and entropy(△S~Θ) during the biosorption were determined. The results show that the biosorption process of Cu( II) ions by chemically treated orange peel is feasible, spontaneous and exothermic under studied conditions. Equilibrium is well described by Langmuir equation with the maximum biosorption capacity(q_m) for Cu( II) as 72.73 mg/g and kinetics is found to fit pseudo-second order type biosorption kinetics. As the temperature increases from 16 ℃ to 60 ℃, copper biosorption decreases. The loaded biosorbent is regenerated using HC1 solution for repeatedly use for five times with little loss of biosorption capacity.

  20. Efficiency of modified chemical remediation techniques for soil contaminated by organochlorine pesticides

    Science.gov (United States)

    Correa-Torres, S. N.; Kopytko, M.; Avila, S.

    2016-07-01

    This study reports the optimization of innovation chemical techniques in order to improve the remediation of soils contaminated with organochloride pesticides. The techniques used for remediation were dehalogenation and chemical oxidation in soil contaminated by pesticides. These techniques were applied sequentially and combined to evaluate the design optimize the concentration and contact time variables. The soil of this study was collect in cotton crop zone in Agustin Codazzi municipality, Colombia, and its physical properties was measure. The modified dehalogenation technique of EPA was applied on the contaminated soil by adding Sodium Bicarbonate solution at different concentrations and rates during 4, 7 and 14 days, subsequently oxidation technique was implemented by applying a solution of KMnO4 at different concentration and reaction times. Organochlorine were detected by Gas Chromatography analysis coupled Mass Spectrometry and its removals were between 85.4- 90.0% of compounds such as 4, 4’-DDT, 4,4’-DDD, 4,4-DDE, trans-Clordane y Endrin. These results demonstrate that the technique of dehalogenation with oxidation chemistry can be used for remediation soils contaminated by organochloride pesticides.

  1. Chemically and biologically modified activated carbon sorbents for the removal of lead ions from aqueous media.

    Science.gov (United States)

    Mahmoud, Mohamed E; Abdel-Fattah, Tarek M; Osman, Maher M; Ahmed, Somia B

    2012-01-01

    A method is described for hybridization of the adsorption and biosorption characteristics of chemically treated commercial activated carbon and baker's yeast, respectively, for the formation of environmental friendly multifunctional sorbents. Activated carbon was loaded with baker's yeast after acid-base treatment. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) Spectroscopy were used to characterize these sorbents. Moreover, the sorption capabilities for lead (II) ions were evaluated. A value of 90 μmol g(-1) was identified as the maximum sorption capacity of activated carbon. Acid-base treatment of activated carbon was found to double the sorption capacity (140-180 μmol g(-1)). Immobilization of baker's yeast on the surface of activated carbon sorbents was found to further improve the sorption capacity efficiency of lead to 360, 510 and 560 μmol g(-1), respectively. Several important factors such as pH, contact time, sorbent dose, lead concentration and interfering ions were examined. Lead sorption process was studied and evaluated by several adsorption isotherms and found to follow the Langmuir and BET models. The potential applications of various chemically and biologically modified sorbents and biosorbents for removal of lead from real water matrices were also investigated via multistage micro-column technique and the results referred to excellent recovery values of lead (95.0-99.0 ± 3.0-5.0 %).

  2. Surface chemical and biological characterization of flax fabrics modified with silver nanoparticles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Paladini, F., E-mail: federica.paladini@unisalento.it [Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce (Italy); Picca, R.A.; Sportelli, M.C.; Cioffi, N. [Department of Chemistry, University of Bari “Aldo Moro”, Via Orabona 4, 70126 Bari (Italy); Sannino, A.; Pollini, M. [Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce (Italy)

    2015-07-01

    Silver nanophases are increasingly used as effective antibacterial agent for biomedical applications and wound healing. This work aims to investigate the surface chemical composition and biological properties of silver nanoparticle-modified flax substrates. Silver coatings were deposited on textiles through the in situ photo-reduction of a silver solution, by means of a large-scale apparatus. The silver-coated materials were characterized through X-ray Photoelectron Spectroscopy (XPS), to assess the surface elemental composition of the coatings, and the chemical speciation of both the substrate and the antibacterial nanophases. A detailed investigation of XPS high resolution regions outlined that silver is mainly present on nanophases' surface as Ag{sub 2}O. Scanning electron microscopy and energy dispersive X-ray spectroscopy were also carried out, in order to visualize the distribution of silver particles on the fibers. The materials were also characterized from a biological point of view in terms of antibacterial capability and cytotoxicity. Agar diffusion tests and bacterial enumeration tests were performed on Gram positive and Gram negative bacteria, namely Staphylococcus aureus and Escherichia coli. In vitro cytotoxicity tests were performed through the extract method on murine fibroblasts in order to verify if the presence of the silver coating affected the cellular viability and proliferation. Durability of the coating was also assessed, thus confirming the successful scaling up of the process, which will be therefore available for large-scale production. - Highlights: • Silver nanophases are increasingly used as effective antibacterial agent for biomedical applications. • Silver coatings were deposited on textiles through the in situ photo-reduction of a silver solution. • Flax fabrics were characterized from a biological and surface chemical point of view. • Scaling up of the process was confirmed.

  3. Adhesion force interactions between cyclopentane hydrate and physically and chemically modified surfaces.

    Science.gov (United States)

    Aman, Zachary M; Sloan, E Dendy; Sum, Amadeu K; Koh, Carolyn A

    2014-12-01

    Interfacial interactions between liquid-solid and solid-solid phases/surfaces are of fundamental importance to the formation of hydrate deposits in oil and gas pipelines. This work establishes the effect of five categories of physical and chemical modification to steel on clathrate hydrate adhesive force: oleamide, graphite, citric acid ester, nonanedithiol, and Rain-X anti-wetting agent. Hydrate adhesive forces were measured using a micromechanical force apparatus, under both dry and water-wet surface conditions. The results show that the graphite coating reduced hydrate-steel adhesion force by 79%, due to an increase in the water wetting angle from 42 ± 8° to 154 ± 7°. Two chemical surface coatings (nonanedithiol and the citric acid ester) induced rapid hydrate growth in the hydrate particles; nonanedithiol increased hydrate adhesive force by 49% from the baseline, while the citric acid ester coating reduced hydrate adhesion force by 98%. This result suggests that crystal growth may enable a strong adhesive pathway between hydrate and other crystalline structures, however this effect may be negated in cases where water-hydrocarbon interfacial tension is minimised. When a liquid water droplet was placed on the modified steel surfaces, the graphite and citric acid ester became less effective at reducing adhesive force. In pipelines containing a free water phase wetting the steel surface, chemical or physical surface modifications alone may be insufficient to eliminate hydrate deposition risk. In further tests, the citric acid ester reduced hydrate cohesive forces by 50%, suggesting mild activity as a hybrid anti-agglomerant suppressing both hydrate deposition and particle agglomeration. These results demonstrate a new capability to develop polyfunctional surfactants, which simultaneously limit the capability for hydrate particles to aggregate and deposit on the pipeline wall. PMID:25332072

  4. Effect of emulsifiers on complexation and retrogradation characteristics of native and chemically modified White sorghum (Sorghum bicolor) starch

    International Nuclear Information System (INIS)

    Highlights: ► Sorghum starches were chemically modified. ► Starch–lipid complexes were studied in the presence of emulsifiers. ► Type II complexes were also detected in native and oxidized starches on adding GMS. ► Starch–lipid complexes sharply reduced retrogradation in modified starches. - Abstract: The effect of emulsifiers on complexation and retrogradation characteristics of native and chemically modified white sorghum starches was studied. Complex forming tendency of white sorghum starch with commercially available emulsifiers GMS and DATEM improved after acetylation. Presence of emulsifiers reduced λmax (wavelength of maximum absorbance) both for native and modified sorghum starches suggesting lower availability of amylose chains to complex with iodine. In native white sorghum starch (NWSS) and oxidized white sorghum starch (OWSS), both Type I and Type II starch–lipid complexes were observed on addition of 1.0% GMS prior to gelatinization. Acetylated-oxidized white sorghum starch (AOWSS) formed weakest complexes among all the modified starches. The results revealed that antistaling characteristics of modified sorghum starches were enhanced when used in combination with emulsifiers. The most prominent decline in reassociative capability among modified starches was observed for acetylated starches.

  5. Antibacterial activity of Brazilian Amazon plant extracts

    Directory of Open Access Journals (Sweden)

    Ivana Barbosa Suffredini

    2006-12-01

    Full Text Available Infections caused by multiresistant bacteria are a widespread problem, especially in intensive care units. New antibiotics are necessary, and we need to search for alternatives, including natural products. Brazil is one of the hottest spots in the world in terms of biodiversity, but little is known about the chemical and pharmacological properties of most of the plants found in the Amazon rain forest and the Atlantic Forest. We screened 1,220 organic and aqueous extracts, obtained from Amazon and Atlantic rain forest plants, against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and E. coli. Seventeen organic and aqueous extracts obtained from 16 plants showed activity against both Gram-positive bacteria. None of the extracts showed relevant activity against the Gram-negative E. coli and Pseudomonas aeruginosa.

  6. Adsorption Studies of Phenol Using Thermally and Chemically Modified Rice Husk as Adsorbents

    Directory of Open Access Journals (Sweden)

    *M. M. Yousaf

    2014-03-01

    Full Text Available Most of the Phenols are hazardous substances and some are supposed to have carcinogenic activity. Thus it is necessary to remove Phenolics and other aromatics from the aqueous ecosystem. Traditional processes for the removal of Phenolics compounds are extraction, adsorption on granulated activated carbon, steam distillation, chemical and bacterial techniques. Literature survey show a number of methods like oxidation, ion exchange, reverse osmosis, electrochemical oxidation and adsorption. Phenol removal by process like, adsorption is the best method of choice as it can remove most of phenols in simple and easy way. In recent past; agricultural by-products such as, maize cob, date stone, apricot Stones, rice bran, and bagass pith have been extensively studied and used as adsorbents for the adsorption of hazardous substances from wastewater. In the present study we tried modified rice husks as potential adsorbents for the removal of Phenol from aqueous system. Batch mode studies were carried out. Isotherm data was generated and fitted in Freundlich and Langmuir equation to explain the phenomenon of adsorption. The adsorption capacities based on Langmuir model (Qm of the 3 adsorbents were found to be 0.81 for raw husk (RH, 0.395 for the Grafted (G and 2.306 mg/g for the Charred (C. The R2 values were 0.92 for raw husk, 0.97 for grafted and 0.91 for charred husk. Based on Freundlich model the adsorption capacities (K were 2.94, 2.29 and 1.25mg/g for Raw husk, grafted husk and charred husk. The R2 values were found to be 0.72, 0.95 and 0.83 for the raw husk, grafted husk and charred husk respectively. Our result showed that modified rice husks could be used as potential adsorbents for Phenol removal from aqueous system.

  7. Recognition of RNA duplexes by chemically modified triplex-forming oligonucleotides.

    Science.gov (United States)

    Zhou, Yuan; Kierzek, Elzbieta; Loo, Zi Ping; Antonio, Meraldo; Yau, Yin Hoe; Chuah, York Wieo; Geifman-Shochat, Susana; Kierzek, Ryszard; Chen, Gang

    2013-07-01

    Triplex is emerging as an important RNA tertiary structure motif, in which consecutive non-canonical base pairs form between a duplex and a third strand. RNA duplex region is also often functionally important site for protein binding. Thus, triplex-forming oligonucleotides (TFOs) may be developed to regulate various biological functions involving RNA, such as viral ribosomal frameshifting and reverse transcription. How chemical modification in TFOs affects RNA triplex stability, however, is not well understood. Here, we incorporated locked nucleic acid, 2-thio U- and 2'-O methyl-modified residues in a series of all pyrimidine RNA TFOs, and we studied the binding to two RNA hairpin structures. The 12-base-triple major-groove pyrimidine-purine-pyrimidine triplex structures form between the duplex regions of RNA/DNA hairpins and the complementary RNA TFOs. Ultraviolet-absorbance-detected thermal melting studies reveal that the locked nucleic acid and 2-thio U modifications in TFOs strongly enhance triplex formation with both parental RNA and DNA duplex regions. In addition, we found that incorporation of 2'-O methyl-modified residues in a TFO destabilizes and stabilizes triplex formation with RNA and DNA duplex regions, respectively. The (de)stabilization of RNA triplex formation may be facilitated through modulation of van der Waals contact, base stacking, hydrogen bonding, backbone pre-organization, geometric compatibility and/or dehydration energy. Better understanding of the molecular determinants of RNA triplex structure stability lays the foundation for designing and discovering novel sequence-specific duplex-binding ligands as diagnostic and therapeutic agents targeting RNA. PMID:23658228

  8. Chemical Sensors Based on IR Spectroscopy and Surface-Modified Waveguides

    Science.gov (United States)

    Lopez, Gabriel P.; Niemczyk, Thomas

    1999-01-01

    Sol-gel processing techniques have been used to apply thin porous films to the surfaces of planar infrared (IR) waveguides to produce widely useful chemical sensors. The thin- film coating serves to diminish the concentration of water and increase the concentration of the analyte in the region probed by the evanescent IR wave. These porous films are composed of silica, and therefore, conventional silica surface modification techniques can be used to give the surface a specific functional character. The sol-gel film was surface-modified to make the film highly hydrophobic. These sensors were shown to be capable of detecting non-polar organic analytes, such as benzonitrile, in aqueous solution with detection limits in the ppb range. Further, these porous sol-gel structures allow the analytes to diffuse into and out of the films rapidly, thus reaching equilibrium in less than ten seconds. These sensors are unique because of the fact that their operation is based on the measurement of an IR absorption spectrum. Thus, these sensors are able to identify the analytes as well as measure concentration with high sensitivity. These developments have been documented in previous reports and publications. Recently, we have also targeted detection of the polar organic molecules acetone and isopropanol in aqueous solution. Polar organics are widely used in industrial and chemical processes, hence it is of interest to monitor their presence in effluents or decontamination process flows. Although large improvements in detection limits were expected with non-polar organic molecules in aqueous solutions using very hydrophobic porous sol-gel films on silicon attenuated total reflectance (Si ATR) waveguides, it was not as clear what the detection enhancements might be for polar organic molecules. This report describes the use of modified sol-gel-coated Si ATR sensors for trace detection and quantitation of small polar organic molecules in aqueous solutions. The detection of both acetone

  9. Supported liquid membrane stability in chiral resolution by chemically and physically modified membranes

    Energy Technology Data Exchange (ETDEWEB)

    Molinari, R.; Argurio, P. [Arcavata di Rende Univ. of Calabria, Arcavata di Rende, CS (Italy). Dept. of Chemical and Materials Engineering

    2001-04-01

    In the present work some stability studies on Supported Liquid Membranes (SLMs) to be used for chiral separations were realized. In particular, primary aim was to determine how a modification of the support surface influences the SLM stability. First, the procedure for support modification was optimised, making a screening of various compounds (sulphuric acid, nitric acid, chromic acid, sodium dodecyl sulphate (SDS), glycerol, oleic alcohol, propylene glycol (PPG), bovine serum albumin (BSA)) and testing their performance by means of contact angle measurements. Next, a second screening was realized by permeation tests in a stirred cell. Finally, to compare the stability of modified with unmodified support in a process of interest for chemical and/or biochemical industries, some permeation tests for resolution of DNB-DL-Leucine were realized in a re-circulation system. Results showed a better surface hydrophilization of chemically modified support and better stability of the sulphonated support. However, in operating conditions a little high stability of the unmodified support was obtained. [Italian] Nel presente lavoro sono stati realizzati degli studi di stabilita' di Membrane Liquide Supportate (SLMs) da impiegare in separazioni chirali. In particolare, obiettivo principale e' stato quello di determinare l'influenza che una modifica della superficie del supporto ha sulla stabilita' della SLM. Cosi', in un primo momento, e' stata ottimizzata le procedura di modifica del supporto, facendo una selezione tra vari composti (acido solforico, acido nitrico, acido cromico, sodio dodecil solfato (SDS), glicerolo, alcool oleico, glicole propilenico (PPG), siero di albumina bovina (BSA)) basata su misure dell'angolo di contatto. Successivamente, e' stata realizzata una seconda selezione mediante prove di permeazione in una cella agitata. Infine, con lo scopo di confrontare la stabilita' della SLM con supporto modificato rispetto

  10. Potential groundwater contribution to Amazon evapotranspiration

    Directory of Open Access Journals (Sweden)

    Y. Fan

    2010-07-01

    Full Text Available Climate and land ecosystem models simulate a dry-season vegetation stress in the Amazon forest, but observations show enhanced growth in response to higher radiation under less cloudy skies, indicating an adequate water supply. Proposed mechanisms include larger soil water store and deeper roots in nature and the ability of roots to move water up and down (hydraulic redistribution. Here we assess the importance of the upward soil water flux from the groundwater driven by capillarity. We present a map of water table depth from observations and groundwater modeling, and a map of potential capillary flux these water table depths can sustain. The maps show that the water table beneath the Amazon can be quite shallow in lowlands and river valleys (<5 m in 36% and <10 m in 60% of Amazonia. The water table can potentially sustain a capillary flux of >2.1 mm day−1 to the land surface averaged over Amazonia, but varies from 0.6 to 3.7 mm day−1 across nine study sites. Current models simulate a large-scale reduction in dry-season photosynthesis under today's climate and a possible dieback under projected future climate with a longer dry season, converting the Amazon from a net carbon sink to a source and accelerating warming. The inclusion of groundwater and capillary flux may modify the model results.

  11. The chemical and catalytic properties of nanocrystalline metal oxides prepared through modified sol-gel synthesis

    Science.gov (United States)

    Carnes, Corrie Leigh

    The goal of this research was to synthesize, characterize and study the chemical properties of nanocrystalline metal oxides. Nanocrystalline (NC) ZnO, CuO, NiO, Al2O3, and the binary Al2O 3/MgO and ZnO/CuO were prepared through modified sol gel methods. These NC metal oxides were studied in comparison to the commercial (CM) metal oxides. The samples were characterized by XRD, TGA, FTIR, BET, and TEM. The NC samples were all accompanied by a significant increase in surface area and decrease in crystallite size. Several chemical reactions were studied to compare the NC samples to the CM samples. One of the reactions involved a high temperature reaction between carbon tetrachloride and the oxide to form carbon dioxide and the corresponding metal chloride. A similar high temperature reaction was conducted between the metal oxide and hydrogen sulfide to form water and the corresponding metal sulfide. A room temperature gas phase adsorption was studied where SO2 was adsorbed onto the oxide. A liquid phase adsorption conducted at room temperature was the destructive adsorption of paraoxon (a toxic insecticide). In all reactions the NC samples exhibited greater activity, destroying or adsorbing a larger amount of the toxins compared to the CM samples. To better study surface area effects catalytic reactions were also studied. The catalysis of methanol was studied over the nanocrystalline ZnO, CuO, NiO, and ZnO/CuO samples in comparison to their commercial counterparts. In most cases the NC samples proved to be more active catalysts, having higher percent conversions and turnover numbers. A second catalytic reaction was also studied, this reaction was investigated to look at the support effects. The catalysis of cyclopropane to propane was studied over Pt and Co catalysts. These catalysts were supported onto NC and CM alumina by impregnation. By observing differences in the catalytic behavior, support effects have become apparent.

  12. Enhanced forward osmosis from chemically modified polybenzimidazole (PBI) nanofiltration hollow fiber membranes with a thin wall

    KAUST Repository

    Wang, Kai Yu

    2009-04-01

    To develop high-flux and high-rejection forward osmosis (FO) membranes for water reuses and seawater desalination, we have fabricated polybenzimidazole (PBI) nanofiltration (NF) hollow fiber membranes with a thin wall and a desired pore size via non-solvent induced phase inversion and chemically cross-linking modification. The cross-linking by p-xylylene dichloride can finely tune the mean pore size and enhance the salt selectivity. High water permeation flux and improved salt selectivity for water reuses were achieved by using the 2-h modified PBI NF membrane which has a narrow pore size distribution. Cross-linking at a longer time produces even a lower salt permeation flux potentially suitable for desalination but at the expense of permeation flux due to tightened pore sizes. It is found that draw solution concentration and membrane orientations are main factors determining the water permeation flux. In addition, effects of membrane morphology and operation conditions on water and salt transport through membrane have been investigated. © 2008 Elsevier Ltd. All rights reserved.

  13. A Novel Chemically Modified Curcumin Reduces Severity of Experimental Periodontal Disease in Rats: Initial Observations

    Directory of Open Access Journals (Sweden)

    Muna S. Elburki

    2014-01-01

    Full Text Available Tetracycline-based matrix metalloproteinase- (MMP- inhibitors are currently approved for two inflammatory diseases, periodontitis and rosacea. The current study addresses the therapeutic potential of a novel pleiotropic MMP-inhibitor not based on an antibiotic. To induce experimental periodontitis, endotoxin (LPS was repeatedly injected into the gingiva of rats on one side of the maxilla; the contralateral (control side received saline injections. Two groups of rats were treated by daily oral intubation with a chemically modified curcumin, CMC 2.24, for two weeks; the control groups received vehicle alone. After sacrifice, gingiva, blood, and maxilla were collected, the jaws were defleshed, and periodontal (alveolar bone loss was quantified morphometrically and by μ-CT scan. The gingivae were pooled per experimental group, extracted, and analyzed for MMPs (gelatin zymography; western blot and for cytokines (e.g., IL-1β; ELISA; serum and plasma samples were analyzed for cytokines and MMP-8. The LPS-induced pathologically excessive bone loss was reduced to normal levels based on either morphometric (P=0.003 or μ-CT (P=0.008 analysis. A similar response was seen for MMPs and cytokines in the gingiva and blood. This initial study, on a novel triketonic zinc-binding CMC, indicates potential efficacy on inflammatory mediators and alveolar bone loss in experimental periodontitis and warrants future therapeutic and pharmacokinetic investigations.

  14. Chemically modified peptide scaffolds target the CFTR-associated ligand PDZ domain.

    Directory of Open Access Journals (Sweden)

    Jeanine F Amacher

    Full Text Available PDZ domains are protein-protein interaction modules that coordinate multiple signaling and trafficking pathways in the cell and that include active therapeutic targets for diseases such as cancer, cystic fibrosis, and addiction. Our previous work characterized a PDZ interaction that restricts the apical membrane half-life of the cystic fibrosis transmembrane conductance regulator (CFTR. Using iterative cycles of peptide-array and solution-binding analysis, we targeted the PDZ domain of the CFTR-Associated Ligand (CAL, and showed that an engineered peptide inhibitor rescues cell-surface expression of the most common CFTR disease mutation ΔF508. Here, we present a series of scaffolds containing chemically modifiable side chains at all non-motif positions along the CAL PDZ domain binding cleft. Concordant equilibrium dissociation constants were determined in parallel by fluorescence polarization, isothermal titration calorimetry, and surface plasmon resonance techniques, confirming robust affinity for each scaffold and revealing an enthalpically driven mode of inhibitor binding. Structural studies demonstrate a conserved binding mode for each peptide, opening the possibility of combinatorial modification. Finally, we diversified one of our peptide scaffolds with halogenated substituents that yielded modest increases in binding affinity. Overall, this work validates our approach and provides a stereochemical foundation for further CAL inhibitor design and screening.

  15. Application of chemically modified beach sand as low cost efficient adsorbent for dye removal

    Directory of Open Access Journals (Sweden)

    Reza Ansari

    2013-10-01

    Full Text Available In the current work, beach sand (BS and beach sand coated with polyaniline (BS/Pani were used as an efficient green adsorbent for dye removal from aqueous solutions. Methylene blue (MB was chosen as a test probe for the evaluation of the selected adsorbents for dye removal efficiency. The adsorption experiments were carried out in batch system and the effect of some important empirical parameters affecting adsorption processes were then investigated. The experimental data were also analyzed by Langmuir and Freundlich adsorption models. Based on the correlation coefficient values obtained (R2, it was found that equilibrium data for both adsorbents fitted well with both models. Adsorption data were also examined by pseudo-first-order and pseudo-second-order models and their respective rate constants were estimated. It was found that sorption of MB dye onto BS/Pani is fitted very well with pseudo-second-order kinetic model. Using the equilibrium concentration constants obtained at different temperatures, important thermodynamic parameters of the sorption process were calculated. It was found that the chemically modified beach sand is an effective and low cost adsorbent for dye removal from aqueous solutions.

  16. A novel chemically modified curcumin reduces severity of experimental periodontal disease in rats: initial observations.

    Science.gov (United States)

    Elburki, Muna S; Rossa, Carlos; Guimaraes, Morgana R; Goodenough, Mark; Lee, Hsi-Ming; Curylofo, Fabiana A; Zhang, Yu; Johnson, Francis; Golub, Lorne M

    2014-01-01

    Tetracycline-based matrix metalloproteinase- (MMP-) inhibitors are currently approved for two inflammatory diseases, periodontitis and rosacea. The current study addresses the therapeutic potential of a novel pleiotropic MMP-inhibitor not based on an antibiotic. To induce experimental periodontitis, endotoxin (LPS) was repeatedly injected into the gingiva of rats on one side of the maxilla; the contralateral (control) side received saline injections. Two groups of rats were treated by daily oral intubation with a chemically modified curcumin, CMC 2.24, for two weeks; the control groups received vehicle alone. After sacrifice, gingiva, blood, and maxilla were collected, the jaws were defleshed, and periodontal (alveolar) bone loss was quantified morphometrically and by μ-CT scan. The gingivae were pooled per experimental group, extracted, and analyzed for MMPs (gelatin zymography; western blot) and for cytokines (e.g., IL-1β; ELISA); serum and plasma samples were analyzed for cytokines and MMP-8. The LPS-induced pathologically excessive bone loss was reduced to normal levels based on either morphometric (P = 0.003) or μ-CT (P = 0.008) analysis. A similar response was seen for MMPs and cytokines in the gingiva and blood. This initial study, on a novel triketonic zinc-binding CMC, indicates potential efficacy on inflammatory mediators and alveolar bone loss in experimental periodontitis and warrants future therapeutic and pharmacokinetic investigations. PMID:25104884

  17. Removal of heavy metals from aqueous phases using chemically modified waste Lyocell fiber.

    Science.gov (United States)

    Bediako, John Kwame; Wei, Wei; Kim, Sok; Yun, Yeoung-Sang

    2015-12-15

    In this study, an outstanding performance of chemically modified waste Lyocell for heavy metals treatment is reported. The sorbent, which was prepared by a simple and concise method, was able to bind heavy metals such as Pb(II), Cu(II) and Cd(II), with very high efficiencies. The binding mechanisms were studied through adsorption and standard characterization tests such as scanning electron microscopy, energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction analyses. Adsorption kinetics was very fast and attained equilibrium within 5 min in all metals studied. The maximum single metal uptakes were 531.29±0.28 mg/g, 505.64±0.21 mg/g, and 123.08±0.26 mg/g for Pb(II), Cd(II) and Cu(II), respectively. In ternary metal systems, Cu(II) selectivity was observed and the underlying factors were discussed. The sorbent by its nature, could be very effective in treating large volumes of wastewater with the contact of very little amount.

  18. Changes in the Chemical Composition and Decay Resistance of Thermally-Modified Hevea brasiliensis Wood.

    Science.gov (United States)

    Severo, Elias Taylor Durgante; Calonego, Fred Willians; Sansígolo, Cláudio Angeli; Bond, Brian

    2016-01-01

    In this study the effect of thermal treatment on the equilibrium moisture content, chemical composition and biological resistance to decay fungi of juvenile and mature Hevea brasiliensis wood (rubber wood) was evaluated. Samples were taken from a 53-year-old rubber wood plantation located in Tabapuã, Sao Paulo, Brazil. The samples were thermally-modified at 180°C, 200°C and 220°C. Results indicate that the thermal modification caused: (1) a significant increase in the extractive content and proportional increase in the lignin content at 220°C; (2) a significant decrease in the equilibrium moisture content, holocelluloses, arabinose, galactose and xylose content, but no change in glucose content; and (3) a significant increase in wood decay resistance against both Pycnoporus sanguineus (L.) Murrill and Gloeophyllum trabeum (Pers.) Murrill decay fungi. The greatest decay resistance was achieved from treatment at 220°C which resulted in a change in wood decay resistance class from moderately resistant to resistant. Finally, this study also demonstrated that the influence of thermal treatment in mature wood was lower than in juvenile wood. PMID:26986200

  19. Removal of Cu(II) from aqueous solutions using chemically modified chitosan

    International Nuclear Information System (INIS)

    Chemically modified chitosan namely epichlorohydrin cross-linked xanthate chitosan (ECXCs) has been used for the removal of Cu(II) ions from aqueous medium. The influence of various operating parameters such as pH, temperature, sorbent dosage, initial concentration of Cu(II) ions and contact time on the adsorption capacity of ECXCs has been investigated. Thermodynamic parameters namely ΔGo, ΔHo and ΔSo of the Cu(II) adsorption process have been calculated. Differential anodic stripping voltammetric technique was used to determine the concentration of Cu(II) in the test solution before and after adsorption. The nature of the possible adsorbent-metal ion interactions was studied by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The studies showed that the adsorption of Cu(II) on ECXCs strongly depends on pH and temperature. The maximum adsorption capacity was observed at pH 5.0 and the adsorption capacity of ECXCs increased with increasing temperature indicating the endothermic nature of adsorption process. Langmuir and Freundlich adsorption equations were used to fit the experimental data. The adsorption process is found to follow the pseudo-second-order kinetic model. The maximum adsorption capacity was found to be 43.47 mg g-1 from the Langmuir isotherm model at 50 deg. C. During desorption studies 97-100% of adsorbed copper ion is released into solution in presence of 1N EDTA, HCl and H2SO4.

  20. Chemically modified graphene films for high-performance optical NO2 sensors.

    Science.gov (United States)

    Xing, Fei; Zhang, Shan; Yang, Yong; Jiang, Wenshuai; Liu, Zhibo; Zhu, Siwei; Yuan, Xiaocong

    2016-08-01

    Various graphene-based gas sensors that operate based on the electrical properties of graphene have been developed for accurate detection of gas components. However, electronic graphene-based gas sensors are unsafe under explosive atmospheres and sensitive to electromagnetic interference. Here, a novel optical graphene-based gas sensor for NO2 detection is established based on surface chemical modification of high-temperature-reduced graphene oxide (h-rGO) films with sulfo groups. Sulfo group-modified h-rGO (S-h-rGO) films with a thickness of several nanometers exhibit excellent performance in NO2 detection at room temperature and atmospheric pressure based on the polarization absorption effect of graphene. Initial slope analysis of the S-h-rGO sensor indicates that it has a limit of detection of 0.28 ppm and a response time of 300 s for NO2 gas sensing. Furthermore, the S-h-rGO sensor also possesses the advantages of good linearity, reversibility, selectivity, non-contact operation, low cost and safety. This novel optical gas sensor has the potential to serve as a general platform for the selective detection of a variety of gases with high performance. PMID:27265308

  1. Adhesion-dependent negative friction coefficient on chemically modified graphite at the nanoscale

    Science.gov (United States)

    Deng, Zhao; Smolyanitsky, Alex; Li, Qunyang; Feng, Xi-Qiao; Cannara, Rachel J.

    2012-12-01

    From the early tribological studies of Leonardo da Vinci to Amontons’ law, friction has been shown to increase with increasing normal load. This trend continues to hold at the nanoscale, where friction can vary nonlinearly with normal load. Here we present nanoscale friction force microscopy (FFM) experiments for a nanoscale probe tip sliding on a chemically modified graphite surface in an atomic force microscope (AFM). Our results demonstrate that, when adhesion between the AFM tip and surface is enhanced relative to the exfoliation energy of graphite, friction can increase as the load decreases under tip retraction. This leads to the emergence of an effectively negative coefficient of friction in the low-load regime. We show that the magnitude of this coefficient depends on the ratio of tip-sample adhesion to the exfoliation energy of graphite. Through both atomistic- and continuum-based simulations, we attribute this unusual phenomenon to a reversible partial delamination of the topmost atomic layers, which then mimic few- to single-layer graphene. Lifting of these layers with the AFM tip leads to greater deformability of the surface with decreasing applied load. This discovery suggests that the lamellar nature of graphite yields nanoscale tribological properties outside the predictive capacity of existing continuum mechanical models.

  2. Chemically modified tetracyclines: Novel therapeutic agents in the management of chronic periodontitis

    Directory of Open Access Journals (Sweden)

    Rupali Agnihotri

    2012-01-01

    Full Text Available Chronic periodontitis is a complex infection initiated by gram-negative bacteria which destroy the supporting structures of the tooth. Recently, it has been recognized that it is the host response to bacterial infection which causes greater destruction of the connective tissue elements, periodontal ligament and alveolar bone in periodontitis. This has led to the development of various host modulating approaches to target cells and their destructive mediators involved in tissue degradation. Chemically modified tetracyclines (CMTs are derivatives of tetracycline group of drugs which lack antimicrobial action but have potent host modulating affects. They inhibit pathologically elevated matrix metal loproteinases, pro-inflammtory cytokines and other destructive mediators. Bone resorption is also suppressed due to their combined anti-proteinase and apoptotic affects on osteoblasts and osteoclasts, respectively. Development of resistant bacteria and gastrointestinal toxicity seen with parent tetracyclines is not produced by CMTs. Hence, CMTs are viewed as potential therapeutic agents in the management of chronic diseases like periodontitis that involve destruction of connective tissue and bone.

  3. Fretting Wear Behavior of Medium Carbon Steel Modified by Low Temperature Gas Multi-component Thermo-chemical Treatment

    Institute of Scientific and Technical Information of China (English)

    LUO Jun; ZHENG Jianfeng; PENG Jinfang; HE Liping; ZHU Minhao

    2010-01-01

    The introduction of surface engineering is expected to be an effective strategy against fretting damage. A large number of studies show that the low gas multi-component (such as carbon, nitrogen, sulphur and oxygen, etc) thermo-chemical treatment(LTGMTT) can overcome the brittleness of nitriding process, and upgrade the surface hardness and improve the wear resistance and fatigue properties of the work-pieces significantly. However, there are few reports on the anti-fretting properties of the LTGMTT modified layer up to now, which limits the applications of fretting. So this paper discusses the fretting wear behavior of modified layer on the surface of LZ50 (0.48%C) steel prepared by low temperature gas multi-component thermo-chemical treatment (LTGMTT) technology. The fretting wear tests of the modified layer flat specimens and its substrate (LZ50 steel) against 52100 steel balls with diameter of 40 mm are carried out under normal load of 150 N and displacement amplitudes varied from 2 μm to 40 μm. Characterization of the modified layer and dynamic analyses in combination with microscopic examinations were performed through the means of scanning electron microscope(SEM), optical microscope(OM), X-ray diffraction(XRD) and surface profilometer. The experimental results showed that the modified layer with a total thickness of 60 μm was consisted of three parts, i.e., loose layer, compound layer and diffusion layer. Compared with the substrate, the range of the mixed fretting regime(MFR) of the LTGMTT modified layer diminished, and the slip regime(SR) of the modified layer shifted to the direction of smaller displacement amplitude. The coefficient of friction(COF) of the modified layer was lower than that of the substrate in the initial stage. For the modified layer, the damage in partial slip regime(PSR) was very slight. The fretting wear mechanism of the modified layer both in MFR and SR was abrasive wear and delamination. The modified layer presented better wear

  4. Deforestation in the Brazilian Amazon

    NARCIS (Netherlands)

    Boekhout van Solinge, T.

    2015-01-01

    This essay takes a (green) criminological and multidisciplinary perspective on deforestation in the Brazilian Amazon, by focusing on the crimes and damages that are associated with Amazonian deforestation. The analysis and results are partly based on longer ethnographic stays in North Brazil (Amazon

  5. Isoprene photochemistry over the Amazon rainforest

    Science.gov (United States)

    Liu, Yingjun; Brito, Joel; Dorris, Matthew R.; Rivera-Rios, Jean C.; Seco, Roger; Bates, Kelvin H.; Artaxo, Paulo; Duvoisin, Sergio; Keutsch, Frank N.; Kim, Saewung; Goldstein, Allen H.; Guenther, Alex B.; Manzi, Antonio O.; Souza, Rodrigo A. F.; Springston, Stephen R.; Watson, Thomas B.; McKinney, Karena A.; Martin, Scot T.

    2016-05-01

    Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK + MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4-0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. A value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (Amazon rainforest.

  6. Direct determination of cadmium in Orujo spirit samples by electrothermal atomic absorption spectrometry: Comparative study of different chemical modifiers

    Energy Technology Data Exchange (ETDEWEB)

    Vilar Farinas, M. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Barciela Garcia, J. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Garcia Martin, S. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Pena Crecente, R. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain); Herrero Latorre, C. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Ciencias, Universidad de Santiago de Compostela, Campus de Lugo, 27002 Lugo (Spain)]. E-mail: cherrero@lugo.usc.es

    2007-05-22

    In this work, several analytical methods are proposed for cadmium determination in Orujo spirit samples using electrothermal atomic absorption spectrometry (ETAAS). Permanent chemical modifiers thermally coated on the platforms inserted in pyrolytic graphite tubes (such as W, Ir, Ru, W-Ir and W-Ru) were comparatively studied in relation to common chemical modifier mixtures [Pd-Mg(NO{sub 3}){sub 2} and (NH{sub 4})H{sub 2}PO{sub 4}-Mg(NO{sub 3}){sub 2}] for cadmium stabilization. Different ETAAS Cd determination methods based on the indicated modifiers have been developed. In each case, pyrolysis and atomization temperatures, atomization shapes, characteristic masses and detection limits as well as other analytical characteristics have been determined. All the assayed modifiers (permanent and conventional) were capable of achieving the appropriate stabilization of the analyte, with the exception of Ru and W-Ru. Moreover, for all developed methods, recoveries (99-102%) and precision (R.S.D. lower than 10%) were acceptable. Taking into account the analytical performance (best detection limit LOD = 0.01 {mu}g L{sup -1}), the ETAAS method based on the use of W as a permanent modifier was selected for further direct Cd determinations in Orujo samples from Galicia (NW Spain). The chosen method was applied in the determination of the Cd content in 38 representative Galician samples. The cadmium concentrations ranged

  7. Chemically modified carbon nanotubes as material enhanced laser desorption ionisation (MELDI) material in protein profiling

    International Nuclear Information System (INIS)

    Biomarkers play a potential role in the early detection and diagnosis of a disease. Our aim is to derivatize carbon nanotubes for exploration of the differences in human body fluids e.g. serum, through matrix assisted laser desorption ionisation/time of flight mass spectrometry (MALDI/TOF-MS) that can be related to disease and subsequently to be employed in the biomarker discovery process. This application we termed as the material enhanced laser desorption ionisation (MELDI). The versatility of this technology is meant to increase the amount of information from biological samples on the protein level, which will have a major impact to serve the cause of diagnostic markers. Serum peptides and proteins are immobilized on derivatized carbon nanotubes, which function as binding material. Protein-loaded suspension is placed on a stainless steel target or buckypaper on aluminum target for direct analysis with MALDI-MS. The elution method to wash the bound proteins from carbon nanotubes was employed to compare with the direct analysis procedure. Elution is carried out by MALDI matrix solution to get them out of the entangled nanotubes, which are difficult to desorb by laser due to the complex nanotube structures. The advantage of these optimized methods compared to the conventional screening methods is the improved sensitivity, selectivity and the short analysis time without prior albumin and immunoglobulin depletion. The comparison of similarly modified diamond and carbon nanotubes exhibit differences in their nature to bind the proteins out of serum due to the differences in their physical characteristics. Infrared (IR) spectroscopy provided hint for the presence of tertiary amine peak at the crucial chemical step of iminodiacetic acid addition to acid chloride functionality on carbon nanotubes. Atomic absorption spectroscopy (AAS) was utilized to quantitatively measure the copper capacity of these derivatized carbon nanotubes which is a direct measure of capacity of

  8. Chemically modified carbon nanotubes as material enhanced laser desorption ionisation (MELDI) material in protein profiling

    Energy Technology Data Exchange (ETDEWEB)

    Najam-ul-Haq, M. [Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innrain 52a, A-6020 Innsbruck (Austria); Rainer, M. [Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innrain 52a, A-6020 Innsbruck (Austria); Schwarzenauer, T. [Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innrain 52a, A-6020 Innsbruck (Austria); Huck, C.W. [Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innrain 52a, A-6020 Innsbruck (Austria)]. E-mail: christian.w.huck@uibk.ac.at; Bonn, G.K. [Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innrain 52a, A-6020 Innsbruck (Austria)

    2006-03-02

    Biomarkers play a potential role in the early detection and diagnosis of a disease. Our aim is to derivatize carbon nanotubes for exploration of the differences in human body fluids e.g. serum, through matrix assisted laser desorption ionisation/time of flight mass spectrometry (MALDI/TOF-MS) that can be related to disease and subsequently to be employed in the biomarker discovery process. This application we termed as the material enhanced laser desorption ionisation (MELDI). The versatility of this technology is meant to increase the amount of information from biological samples on the protein level, which will have a major impact to serve the cause of diagnostic markers. Serum peptides and proteins are immobilized on derivatized carbon nanotubes, which function as binding material. Protein-loaded suspension is placed on a stainless steel target or buckypaper on aluminum target for direct analysis with MALDI-MS. The elution method to wash the bound proteins from carbon nanotubes was employed to compare with the direct analysis procedure. Elution is carried out by MALDI matrix solution to get them out of the entangled nanotubes, which are difficult to desorb by laser due to the complex nanotube structures. The advantage of these optimized methods compared to the conventional screening methods is the improved sensitivity, selectivity and the short analysis time without prior albumin and immunoglobulin depletion. The comparison of similarly modified diamond and carbon nanotubes exhibit differences in their nature to bind the proteins out of serum due to the differences in their physical characteristics. Infrared (IR) spectroscopy provided hint for the presence of tertiary amine peak at the crucial chemical step of iminodiacetic acid addition to acid chloride functionality on carbon nanotubes. Atomic absorption spectroscopy (AAS) was utilized to quantitatively measure the copper capacity of these derivatized carbon nanotubes which is a direct measure of capacity of

  9. Electrochemical impedance spectroscopy for graphene surface modification and protein translocation through the chemically modified graphene nanopore

    Science.gov (United States)

    Tiwari, Purushottam; Shan, Yuping; Wang, Xuewen; Darici, Yesim; He, Jin

    2014-03-01

    The multilayer graphene surface has been modified using mercaptohexadecanoic acid (MHA) and 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-750] (DPPE-PEG750). The surface modifications are evaluated using electrochemical impedance spectroscopy (EIS). EIS measurements show the better graphene surface passivation with DPPE-PEG750 than with MHA. After modification with ferritin, the MHA modified surface shows greater charge transfer resistance (Rct) change than DPPE-PEG750 modified surface. Based on these results the translocations of ferritin through modified graphene nanopore with diameter 5-20 nm are studied. The translocation is more successful through DPPE-PEG750 modified graphene nanopore. This concludes that that the attachment of ferritin to DPPE-PEG750 modified graphene nanopore is not significant compared to MHA modified pore for the ferritin translocation hindrance. These results nicely correlate with the EIS data for respective Rct change of ferritin modified surfaces. P. Tiwari would like to thank FIU School of Integrated Science & Humanity, College Arts & Sciences for the research assistantship.

  10. Chemical characterization and oxidative stability of the oils from three morphotypes of Mauritia flexuosa L.f, from the Peruvian Amazon

    OpenAIRE

    Mancini-Filho, Jorge; Paván Torres, Rosángela; Sotero Solís, Víctor; Vásquez-Ocmín, Pedro G.; Freitas Alvarado, Luis

    2010-01-01

    Three morphotypes of aguaje Mauritia flexuosa were tested, classified by the color of their mesocarpium: “color”, “shambo” and “amarillo”, collected from different areas near the city of Iquitos, Peru. Also, physical-chemical analyses of the mesocarpium were performed, such as the characterization of fatty acids by gas chromatography, determination of β- carotene y α – tocopherol by high efficiency liquid chromatography system in normal and reverse phase and the determination of oxidation ind...

  11. Changes in soil physical and chemical properties in long term improved natural and traditional agroforestry management systems of cacao genotypes in Peruvian Amazon.

    Science.gov (United States)

    Arévalo-Gardini, Enrique; Canto, Manuel; Alegre, Julio; Loli, Oscar; Julca, Alberto; Baligar, Virupax

    2015-01-01

    Growing cacao (Theobroma cacao L.) in an agroforestry system generates a productive use of the land, preserves the best conditions for physical, chemical and biological properties of tropical soils, and plays an important role in improving cacao production and fertility of degraded tropical soils. The aim of this study was to evaluate the impact of two long term agroforestry systems of cacao management on soil physical and chemical properties in an area originally inhabited by 30 years old native secondary forest (SF). The two agroforestry systems adapted were: improved natural agroforestry system (INAS) where trees without economic value were selectively removed to provide 50% shade and improved traditional agroforestry system (ITAS) where all native trees were cut and burnt in the location. For evaluation of the changes of soil physical and chemical properties with time due to the imposed cacao management systems, plots of 10 cacao genotypes (ICS95, UF613, CCN51, ICT1112, ICT1026, ICT2162, ICT2171, ICT2142, H35, U30) and one plot with a spontaneous hybrid were selected. Soil samples were taken at 0-20, 20-40 and 40-60 cm depths before the installation of the management systems (2004), and then followed at two years intervals. Bulk density, porosity, field capacity and wilting point varied significantly during the years of assessment in the different soil depths and under the systems assessed. Soil pH, CEC, exchangeable Mg and sum of the bases were higher in the INAS than the ITAS. In both systems, SOM, Ext. P, K and Fe, exch. K, Mg and Al+H decreased with years of cultivation; these changes were more evident in the 0-20 cm soil depth. Overall improvement of SOM and soil nutrient status was much higher in the ITAS than INAS. The levels of physical and chemical properties of soil under cacao genotypes showed a marked difference in both systems.

  12. Chemical elements in pearl oysters (Paxyodon ponderosus), phytoplankton and estuarine sediments from eastern Amazon (Northern Brazil): Bioaccumulation factors and trophic transfer factors

    Science.gov (United States)

    Vilhena, Maria P. S. P.; Costa, Marcondes L.; Berrêdo, José F.; Paiva, Rosildo S.; Souza, Crisvaldo C. S.

    2016-04-01

    The current study was conducted near Barcarena County, which is a mid-sized urban center where aluminum ore processing industries (bauxite) and Vila do Conde cargo terminal are located. It aims to discuss the bioaccumulation factors as well as factors related to the trophic transfer of chemical elements in water, oyster, phytoplankton and bottom sediments from an estuary in the Brazilian Northern coast. The bioaccumulation factor (BAF), trophic transfer factor (TTF) and biota-sediment-water were used to correlate the contents of chemical elements found in organisms. The sediment, surface water, phytoplankton and pearl oysters chemical composition was analyzed by ICP-OES and ICP-MS. Pearl oysters showed K, Ca, Mg, P, Mn, Fe, Zn, Al, Ba and Pb accumulation, which concentration increase is associated with their diet (phytoplankton). Al concentrations are 14 times higher in pearl oysters (Paxyodon ponderosus), assuming that they are associated with wastewater emissions and with industrialization processes in the area. BAF and BSAF values are 1000 times higher than the metal concentrations in water and bioavailable fraction concentrations. The oyster-phytoplankton trophic transfer factor indicates that P, Ba, Ca, Na, Cd and Zn showed the largest transfers (from 5 to 19). These trophic transfers may be sufficient to cause significant ecotoxicological effects on the region biota.

  13. Utilization of chemically modified citrus reticulata peels for biosorptive removal of acid yellow-73 dye from water

    International Nuclear Information System (INIS)

    Textile effluents contain several varieties of natural and synthetic dyes, which are non-biodegradable. Acid Yellow-73 is one of them. In this research work, adsorptive removal of this dye was investigated using chemically modified Citrus reticulata peels, in batch mode. It was noted that adsorption of dye on Citrus reticulata peels increased by increasing contact time and decreased in basic pH conditions. Langmuir and Freundlich isothermal models were followed by equilibrium data, but the first isotherm fitted the data better, showing that chemisorption occurred more as compared to physiosorption, showing maximum adsorption capacity 96.46 mg.g-1.L-1. The thermodynamic study showed that adsorption of Acid Yellow-73 on chemically modified Citrus reticulata peels was favorable in nature, following pseudo-second order kinetics. (author)

  14. Applicability of Vacuum Impregnation to Modify Physico-Chemical, Sensory and Nutritive Characteristics of Plant Origin Products—A Review

    OpenAIRE

    Elżbieta Radziejewska-Kubzdela; Róża Biegańska-Marecik; Marcin Kidoń

    2014-01-01

    Vacuum impregnation is a non-destructive method of introducing a solution with a specific composition to the porous matrices of fruit and vegetables. Mass transfer in this process is a result of mechanically induced differences in pressure. Vacuum impregnation makes it possible to fill large volumes of intercellular spaces in tissues of fruit and vegetables, thus modifying physico-chemical properties and sensory attributes of products. This method may be used, e.g., to reduce pH and water act...

  15. Impact of chemically-modified tetracycline 3 on intertwined physiological, biochemical, and inflammatory networks in porcine sepsis/ARDS

    OpenAIRE

    Sadowsky, David; Nieman, Gary; Barclay, Derek; Mi, Qi; Zamora, Ruben; Constantine, Gregory; Golub, Lorne; Lee, Hsi-Ming; Roy, Shreyas; Gatto, Louis A; Vodovotz, Yoram

    2015-01-01

    Sepsis can lead to multiple organ dysfunction, including the Acute Respiratory Distress Syndrome (ARDS), due to intertwined, dynamic changes in inflammation and organ physiology. We have demonstrated the efficacy of Chemically-Modified Tetracycline 3 (CMT-3) at reducing inflammation and ameliorating pathophysiology in the setting of a clinically realistic porcine model of ARDS. Here, we sought to gain insights into the derangements that characterize sepsis/ARDS and the possible impact of CMT-...

  16. Physicochemical properties, morphological and X-ray pattern of chemically modified white sorghum starch. (Bicolor-Moench)

    OpenAIRE

    Olayinka, O. O.; Adebowale, K. O.; Olu-Owolabi, I. B.

    2011-01-01

    Starch isolated from white sorghum was subjected to chemical modifications like oxidation, acetylation and acid thinning. Proximate composition of these, such as crude protein, crude fat, moisture content and ash content were studied. Wide angle X-ray diffractograms showed typical ‘A’ pattern characteristic of cereal starches, but significant differences were observed between the X-ray pattern of native and modified starches. Scanning electron microscopy revealed round and polygonal shapes fo...

  17. Chemically modified graphite felt as an efficient cathode in electro-Fenton for p-nitrophenol degradation

    International Nuclear Information System (INIS)

    Highlights: • Chemically modified graphite felt was prepared using ethanol and hydrazine hydrate as reagents. • Carbon nanoparticles with functional groups were deposited on the surface after modification. • The electrochemical activity for ORR and H2O2 generation on the modified electrode was improved. • The cathode modification effictively improved the EF performance for pollutant degradation. - Abstract: A simple method with low-cost chemical reagents ethanol and hydrazine hydrate was used to modify graphite felt as the cathode for electro-Fenton (EF) application, using p-nitrophenol (p-Np) as the model pollutant. Characterized by scanning electron microscope, contact angle, Raman spectrum and X-ray photoelectron spectroscopy, the morphology and surface physicochemical properties after modification were observed considerably changed. After modification, some nanoparticles and oxygen and nitrogen-containing functional groups appeared on the cathode surface, which greatly improved the surface hydrophilic property and the electrocatalytic activity for oxygen reduction reaction. The effects led to the hydrogen peroxide accumulation on the modified cathode markedly increased to 175.8 mg L−1, while that on the unmodified one was only 67.5 mg L−1. p-Np of initial 50 mg L−1 could be completely removed by EF using the modified cathode, and the mineralization ratio reached 51.4%, more than 2 times of the pristine one. After 10 cycles, the mineralization ratio of the modified cathode was still above 45%, suggesting that the modification method can provide an effective approach to improve EF performance, and thus benefits to promote its environmental applications

  18. Amazon: Is Profitability a Possibility?

    Directory of Open Access Journals (Sweden)

    Brett DENNIS

    2014-06-01

    Full Text Available In today’s society, companies seem to all be following the same trend; growth in profitability at all cost. Higher profits, for the most part, leads to more investors and more potential financing. Amazon.com appears to be breaking that trend, however. Their strategy seems to be growth, but not in profits. We would like to look into how and why Amazon is growing at such a fast pace, while their profits are staying steady at a very low level. Is profitability a possibility for Amazon? We believe that a marginal increase in price could accomplish just that, with a minimal impact to consumers.

  19. Renewable resources as reinforcement of polymeric matrices: composites based on phenolic thermosets and chemically modified sisal fibers.

    Science.gov (United States)

    Megiatto, Jackson D; Oliveira, Franciéli B; Rosa, Derval S; Gardrat, Christian; Castellan, Alain; Frollini, Elisabete

    2007-09-11

    Lignocellulosic materials can significantly contribute to the development of composites, since it is possible to chemically and/or physically modify their main components, cellulose, hemicelluloses and lignin. This may result in materials more stable and with more uniform properties. It has previously been shown that chemically modified sisal fibers by ClO(2) oxidation and reaction with FA and PFA presented a thin coating layer of PFA on their surface. FA and PFA were chosen as reagents because these alcohols can be obtained from renewable sources. In the present work, the effects of the polymeric coating layer as coupling agent in phenolic/sisal fibers composites were studied. For a more detailed characterization of the fibers, IGC was used to evaluate the changes that occurred at the sisal fibers surface after the chemical modifications. The dispersive and acid-base properties of untreated and treated sisal fibers surfaces were determined. Biodegradation experiments were also carried out. In a complementary study, another PFA modification was made on sisal fibers, using K2Cr2O(7) as oxidizing agent. In this case the oxidation effects involve mainly the cellulose polymer instead of lignin, as observed when the oxidation was carried out with ClO(2). The SEM images showed that the oxidation of sisal fibers followed by reaction with FA or PFA favored the fiber/phenolic matrix interaction at the interface. However, because the fibers were partially degraded by the chemical treatment, the impact strength of the sisal-reinforced composites decreased. By contrast, the chemical modification of fibers led to an increase of the water diffusion coefficient and to a decrease of the water absorption of the composites reinforced with modified fibers. The latter property is very important for certain applications, such as in the automotive industry. PMID:17676656

  20. Sulfur Fixation by Chemically Modified Red Mud Samples Containing Inorganic Additives: A Parametric Study

    OpenAIRE

    Liu, Yang; LI Yang; Zhou, Feng-shan; Hu, Ying-mo; Zhang, Yi-he

    2016-01-01

    Sulfur retention ability of Bayer red mud from alumina plant was investigated. Bayer red mud modified by fusel salt and waste mother liquor of sodium ferrocyanide as the main sulfur fixation agent and the calcium based natural mineral materials as servicing additives; the experimental results showed the following: (1) Through 10 wt% waste mother liquor of sodium ferrocyanide modifying Bayer red mud, sulfur fixation rate can increase by 13 wt%. (2) Magnesium oxide can obviously improve the sul...

  1. Proximate analysis for amazon biomass

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Antonio Geraldo de Paula; Feitosa Netto, Genesio Batista; Nogueira, Manoel Fernandes Martins; Coutinho, Manoel Fernandes Martins; Coutinho, Hebert Willian Martins; Rendeiro, Goncalo [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Lab. de Engenharia Mecanica (LABGAS)], e-mail: ageraldo@ufpa.br, e-mail: mfmn@ufpa.br, e-mail: rendeiro@ufpa.br

    2006-07-01

    In order to asses the potentiality of Amazon biomass to generate power, either to supply electric energy to the grid or as fuel to plants supplying power for off-grid location, data for their proximate analysis must be available. A literature review on the subject indicated a lack of information and data concerning typical Amazon rain forest species. This work aimed to characterize (proximate analysis) 80 Amazon species in order to evaluate the energy resource from woody biomass wastes in Amazon region. Higher Heating Value, Carbon, Volatile and Ash contents were measured in a dry basis. The measurements were performed obeying the following Brazilian standards, NBR 6923, NBR 8112, NBR 8633, NBR 6922. (author)

  2. Removal of heavy metals from water by zeolite mineral chemically modified. Mercury as a particular case

    International Nuclear Information System (INIS)

    Research works on the removal of mercury from water by zeolite minerals show that a small quantity of this element is sorbed. In this work the mercury sorption from aqueous solutions in the presence and absence of Cu(l l), Ni(l l) and/or Zn(l l) by a Mexican zeolite mineral, natural and modified by cisteaminium chloride or cistaminium dichloride, was investigated in acidic p H. The zeolite minerals were characterized by X- Ray diffraction Ftir, scanning electron microscopy and semiquantitative elemental analysis (EDS), surface area analysis (BET) and thermogravimetric analysis (TGA). Mercury from aqueous solutions was quantified by Atomic absorption spectroscopy. The amount of sulphur on the zeolite samples treated with Na CI and modified with cisteaminium chloride (0.375 mmol/g) or cistaminium dichloride(0.475 mmol/g) was found to be higher than that of the zeolite minerals modified with cisteaminium chloride and cistaminium dichloride without treating them with Na CI. The amount of sulphur on the zeolite minerals modified with thiourea was the lowest. The diffusion coefficients and sorption isotherms for mercury were determined in the natural, treated with Na CI and, treated with Na CI and then modified with the cisteaminium chloride or cistaminium dichloride zeolite samples. The retention of mercury was the highest for the zeolite minerals treated Na CI and then modified with cisteaminium chloride or cistaminium dichloride, with adsorption capacity of 0.0511 and 0.0525 mmol Hg/g, respectively. In this research work, it was found that the retention of mercury by the modified minerals was not affected by the presence of Cu (Il), Zn(l l) y Ni (I l) under the experimental conditions. (Author)

  3. HIGHLY EFFECTIVE CHEMICAL MODIFIERS FOR PRODUCTION OF CONCRETES WITH PRE-SET PROPERTIES

    Directory of Open Access Journals (Sweden)

    Tkach Evgeniya Vladimirovna

    2012-10-01

    Full Text Available The paper demonstrates the application of industrial by-products and recycled materials. Waterproofing admixtures improve the structure and the properties of the cement stone. Development and preparation of highly effective waterproofing modifiers of durable effect, as well as development of the process procedure parameters, including mixing, activation, heat treatment, etc. are to be implemented. The composition of waterproofing modifiers is to be fine-tuned to synergize the behaviour of various ingredients of cement systems to assure the substantial improvement of their strength, freeze- and corrosion resistance. Multi-functional waterproofing admixtures were used to produce highly effective modified concretes. The key idea of the new method of modifying cement-based building materials is that the waterproofing admixture concentration is to exceed 10% of the weight of the binding agent within the per-unit weight of the cement stone, given that its strength does not deteriorate. GKM-type modifier coupled with organo-mineral waterproofing admixture concentration agent GT-M may be recommended for mass use in the manufacturing of hydraulic concrete and reinforced concrete products. Overview of their practical implementation has proven that waterproofing modifier GKM-S, if coupled with waterproofing admixture concentration agent GT-M, improves the corrosion control inside the cement stone and makes it possible to manufacture durable concrete and reinforced concrete products that demonstrate pre-set physical and processing behaviour. Comprehensive concrete modification by modifier GKM-S and waterproofing admixture concentration agent GT-M may be regarded as one of the most ambitious methods of production of highly effective waterproof concretes.

  4. Analogical reasoning in amazons.

    Science.gov (United States)

    Obozova, Tanya; Smirnova, Anna; Zorina, Zoya; Wasserman, Edward

    2015-11-01

    Two juvenile orange-winged amazons (Amazona amazonica) were initially trained to match visual stimuli by color, shape, and number of items, but not by size. After learning these three identity matching-to-sample tasks, the parrots transferred discriminative responding to new stimuli from the same categories that had been used in training (other colors, shapes, and numbers of items) as well as to stimuli from a different category (stimuli varying in size). In the critical testing phase, both parrots exhibited reliable relational matching-to-sample (RMTS) behavior, suggesting that they perceived and compared the relationship between objects in the sample stimulus pair to the relationship between objects in the comparison stimulus pairs, even though no physical matches were possible between items in the sample and comparison pairs. The parrots spontaneously exhibited this higher-order relational responding without having ever before been trained on RMTS tasks, therefore joining apes and crows in displaying this abstract cognitive behavior. PMID:26084679

  5. Chemical characterization and oxidative stability of the oils from three morphotypes of Mauritia flexuosa L.f, from the Peruvian Amazon

    Directory of Open Access Journals (Sweden)

    Mancini-Filho, Jorge

    2010-12-01

    Full Text Available Three morphotypes of aguaje Mauritia flexuosa were tested, classified by the color of their mesocarpium: “color”, “shambo” and “amarillo”, collected from different areas near the city of Iquitos, Peru. Also, physical-chemical analyses of the mesocarpium were performed, such as the characterization of fatty acids by gas chromatography, determination of β- carotene y α – tocopherol by high efficiency liquid chromatography system in normal and reverse phase and the determination of oxidation induction time in the Rancimat apparatus. Proximate, mineral and fatty acid analyses were done on the seeds. The aguaje mesocarpium is rich in oleic oil (“amarillo”: 75.63% ± 0.31, β-carotene (“amarillo”: 342.42ug/g ± 0.71 and α- tocopherol (“color”: 685.81mg/L ± 1.04, plus the morphotype “color” has a superior oxidation induction time compared to other morphotypes with 6.91 ± 0.01. The aguaje seed contains significant amounts of ω6 (linoleic oil in “shambo” with 36.04 ± 0.09%. The results indicate that these oils, regardless their classification, contain important chemical compounds that give them a special nutritive value.Se estudiaron tres morfotipos de aguaje Mauritia flexuosa L. f., clasificados por el color del mesocarpio: “color”, “shambo” y “amarillo”, recogidos de localidades cercanas a la ciudad de Iquitos- Perú. Del mismo modo a partir del mesocarpio se realizaron los análisis fisicoquímicos, la caracterización de los ácidos grasos por cromatografía gaseosa, la determinación de β-caroteno y α– tocoferol por cromatografía líquida de alta eficiencia (HPLC fase reversa y normal y la determinación del tiempo de inducción de la oxidación en el equipo de Rancimat. A partir de la semilla se realizaron los análisis centesimales, de minerales y ácidos grasos. Los mesocarpios de aguaje son ricos en ácido oleico (amarillo: 75.63% ± 0.31, β-caroteno (amarillo: 342.42 ug/g ± 0.71 y

  6. Remote tropical and sub-tropical responses to Amazon deforestation

    Science.gov (United States)

    Badger, Andrew M.; Dirmeyer, Paul A.

    2016-05-01

    Replacing natural vegetation with realistic tropical crops over the Amazon region in a global Earth system model impacts vertical transport of heat and moisture, modifying the interaction between the atmospheric boundary layer and the free atmosphere. Vertical velocity is decreased over a majority of the Amazon region, shifting the ascending branch and modifying the seasonality of the Hadley circulation over the Atlantic and eastern Pacific oceans. Using a simple model that relates circulation changes to heating anomalies and generalizing the upper-atmosphere temperature response to deforestation, agreement is found between the response in the fully-coupled model and the simple solution. These changes to the large-scale dynamics significantly impact precipitation in several remote regions, namely sub-Saharan Africa, Mexico, the southwestern United States and extratropical South America, suggesting non-local climate repercussions for large-scale land use changes in the tropics are possible.

  7. Chemically Modified Starch; Allyl- and Epoxy-Starch Derivatives: Their Synthesis and Characterization

    NARCIS (Netherlands)

    Franssen, M.C.R.; Boeriu, C.

    2014-01-01

    Both native and modified starches, such as starch that is pregelatinized, extruded, acid-converted, cross-linked, and substituted, are widely used in industry. This chapter describes a mild two-step process for the synthesis of novel, highly reactive granular epoxy-starch derivatives. Via this metho

  8. Sulfur Fixation by Chemically Modified Red Mud Samples Containing Inorganic Additives: A Parametric Study

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-01-01

    Full Text Available Sulfur retention ability of Bayer red mud from alumina plant was investigated. Bayer red mud modified by fusel salt and waste mother liquor of sodium ferrocyanide as the main sulfur fixation agent and the calcium based natural mineral materials as servicing additives; the experimental results showed the following: (1 Through 10 wt% waste mother liquor of sodium ferrocyanide modifying Bayer red mud, sulfur fixation rate can increase by 13 wt%. (2 Magnesium oxide can obviously improve the sulfur fixation performance of Bayer red mud and up to a maximum sulfur fixation rate of 47 wt% at adding 1 wt% magnesium oxide. (3 Dolomite enhanced the sulfur fixation performances with the sulfur fixation rate of 68 wt% in optimized condition. (4 Vermiculite dust reduced sulfur dioxide during the fixed-sulfur process of modified Bayer red mud, and the desulphurization ration could reach up to a maximum 76 wt% at 950°C. (5 An advanced three-component sulfur fixation agent was investigated, in which the optimized mass ratio of modified Bayer red mud, dolomite, and vermiculite dust was 70 : 28 : 2 in order, and its sulfur fixation efficiency has reached to a maximum 87 wt% under its 20 wt% dosage in the coal.

  9. Durable nitrate-selective chemically modified field effect transistors based on new polysiloxane membranes

    NARCIS (Netherlands)

    Antonisse, Martijn M.G.; Lugtenberg, Ronnie J.W.; Egberink, Richard J.M.; Engbersen, Johan F.J.; Reinhoudt, David N.

    1996-01-01

    Polysiloxane copolymers with different amounts and types of substituents have been synthesized and characterized. Polar substituents determine the polarity and methacrylate groups allow cross-linking and covalent binding of electroactive species. These chemically well-defined homogeneous polymers ha

  10. Fabrication and characterization of indium sulfide thin films deposited on SAMs modified substrates surfaces by chemical bath deposition

    International Nuclear Information System (INIS)

    In an effort to explore the optoelectronic properties of nanostructured indium sulfide (In2S3) thin films for a wide range of applications, the In2S3 thin films were successfully deposited on the APTS layers (-NH2-terminated) modified ITO glass substrates using the chemical bath deposition technique. The surface morphology, structure and composition of the resultant In2S3 thin films were characterized by FESEM, XRD, and XPS, respectively. Also, the correlations between the optical properties, photocurrent response and the thickness of thin films were established. According to the different deposition mechanisms on the varying SAMs terminational groups, the positive and negative micropatterned In2S3 thin films were successfully fabricated on modified Si substrates surface combining with the ultraviolet lithography process. This offers an attractive opportunity to fabricate patterned In2S3 thin films for controlling the spatial positioning of functional materials in microsystems.

  11. A radiobiological approach to cancer treatment. Possible chemical and physical agents modifying radiosensitivity in comparison with high LET radiations

    International Nuclear Information System (INIS)

    Biological characteristics of high LET radiations are summarized to be low oxygen enhancement ratio, high RBE, low repair and low cell cycle dependency of radiosensitivity. Various chemical modifiers of radiosensitivity and radiological effect of hyperthermia are classified into these four properties. It is evident that we have now various means to mimic high LET radiations as far as biological response is concerned though some of them are still in experimental stage. Among them, the means to cope with hypoxia and repair which are assumed to be the most important causes of radioresistance of human tumors are discussed in some detail. It is expected that through the present seminar we would have consensus to concentrate our effort of development for new modifying means available and useful in developing countries. (author)

  12. A noninterventional study documenting use and success of implants with a new chemically modified titanium surface in daily dental practice.

    Science.gov (United States)

    Luongo, Giuseppe; Oteri, Giacomo

    2010-01-01

    A new chemically modified titanium surface, SLActive, has recently been developed. The results obtained in controlled clinical trials indicate that this implant can be safely used and that it offers predictable results. The goal of this noninterventional study was to verify that the success rates of implants used in daily dental practice are comparable to those reported in controlled clinical trials. This study was a prospective, noninterventional study using implants with a chemically modified surface according to the daily dental practice procedures applied by private practitioners. The choice of the implantation procedure and the loading protocol were the responsibility of the investigator and were chosen according to the patient's needs. Thirty clinical centers actively participated in this study, and 226 patients were treated, of which, 8 patients were lost to follow-up. Because of the noninterventional design of the study, the patients were not selected according to strictly defined inclusion/exclusion criteria. Thus, the study included individuals with risk factors such as smoking (24%), untreated gingivitis or periodontitis (9%), and bruxism (6%). The implants were equally distributed between mandible (46%) and maxilla (54%). A bone augmentation procedure was done in 31% of the cases. Early loading (functional loading between 48 hours and 3 months after implant insertion) was applied most frequently (48%), followed by the conventional loading protocol (3 to 6 months after implant placement, 34%). Immediate restoration and immediate loading were rare (7% and 2%, respectively). Of 276 implants inserted and documented, 5 implants failures were reported, all of which were associated with a sinus floor augmentation procedure. The survival rate was 98.2% at the 1-year follow-up visit. The results showed that implants with a chemically modified surface can be successfully restored with success rates similar to those reported in formal clinical trials under more

  13. Interpenetrating polymer networks based on polyol modified castor oil polyurethane and poly(2-hydroxyethylmethacrylate): Synthesis, chemical, mechanical and thermal properties

    Indian Academy of Sciences (India)

    K Prashantha; K Vasanth Kumar Pai; B S Sherigara; S Prasannakumar

    2001-10-01

    Interpenetrating polymer networks (IPNs) of glycerol modified castor oil polyurethane (GC–PU) and poly[2-hydroxyethylmethacrylate] (PHEMA) were synthesized using benzoyl peroxide as initiator and N,N-methylene bis acrylamide as crosslinker. GC–PU/PHEMA interpenetrating polymer networks were obtained by transfer moulding. These were characterized with respect to their resistance to chemical reagents and mechanical properties such as tensile strength, per cent elongation and shore A hardness. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were undertaken for thermal characterization. The changes in NCO/OH ratio and GC–PU/PHEMA composition on the properties of the IPNs were studied.

  14. Biosorption of Cu (II onto chemically modified waste mycelium of Aspergillus awamori: Equilibrium, kinetics and modeling studies

    Directory of Open Access Journals (Sweden)

    ZDRAVKA VELKOVA

    2012-01-01

    Full Text Available The biosorption potential of chemically modified waste mycelium of industrial xylanase-producing strain Aspergillus awamori for Cu (II removal from aqueous solutions was evaluated. The influence of pH, contact time and initial Cu (II concentration on the removal efficiency was evaluated. Maximum biosorption capacity was reached by sodium hydroxide treated waste fungal mycelium at pH 5.0. The Langmuir adsorption equation matched very well the adsorption equilibrium data in the studied conditions. The process kinetic followed the pseudo-firs order model.

  15. Removal of Chlorinated Chemicals in H2 Feedstock Using Modified Activated Carbon

    Directory of Open Access Journals (Sweden)

    Prapaporn Luekittisup

    2015-01-01

    Full Text Available Activated carbon (GAC was impregnated by sodium and used as adsorbent to remove chlorinated hydrocarbon (CHC gases contaminated in H2 feedstock. The adsorption was carried out in a continuous packed-bed column under the weight hourly space velocity range of 0.8–1.0 hr−1. The adsorption capacity was evaluated via the breakthrough curves. This modified GAC potentially adsorbed HCl and VCM of 0.0681 gHCl/gadsorbent and 0.0026 gVCM/gadsorbent, respectively. It showed higher adsorption capacity than SiO2 and Al2O3 balls for both organic and inorganic CHCs removal. In addition, the kinetic adsorption of chlorinated hydrocarbons on modified GAC fit well with Yoon-Nelson model.

  16. Determination of vanadium in mussels by electrothermal atomic absorption spectrometry without chemical modifiers

    Energy Technology Data Exchange (ETDEWEB)

    Saavedra, Y.; Fernandez, P. [Centro de Control do Medio Marino, Peirao de Vilaxoan s/n, Vilagarcia de Arousa, 36611 Pontevedra (Spain); Gonzalez, A. [Departamento de Quimica Analitica, Nutricion y Bromatologia, Facultad de Quimica, 15706, Santiago de Compostela (Spain)

    2004-05-01

    A method was developed for the quantitative determination of total vanadium concentration in mussels via electrothermal atomic absorption spectrometry (ETAAS). After the microwave digestion of the samples, a program using temperatures of 1600 C and 2600 C for ashing and atomization respectively, without any matrix modifiers, allowed us to obtain results that were satisfactory since they agreed closely with certified reference material values. The detection limit was 0.03 mg kg{sup -1} (dry weight), indicating that the method is suitable for the analysis of mussel samples. This determination was compared with matrix modifiers that have been reported previously. The method was applied to various cultivated and wild mussels from the Galician coast, yielding levels below 1 mg kg{sup -1} (wet weight). (orig.)

  17. Rheological behaviour of polymer-modified bituminous mastics : a comparative analysis between physical and chemical modification

    OpenAIRE

    Shivokhin, Maxim; García Morales, Moisés; Partal López, Pedro; Cuadri Vega, Antonio Abad; Gallegos Montes, Críspulo

    2012-01-01

    Mastic, a bitumen/filler blend which naturally forms when bitumen is mixed with aggregates is the actual product used to bind coarse mineral particles in the asphalt mixtures. As a result, the characterisation of mastics is essential to improve the understanding of the response and performance of asphalt concrete pavements. On the other hand, the lack of experimental data concerning the behaviour of mastics and, above all, polymer-modified mastics has been lately claimed. In that sense, this ...

  18. High-affinity triplex targeting of double stranded DNA using chemically modified peptide nucleic acid oligomers

    OpenAIRE

    Hansen, Mads E.; Bentin, Thomas; Nielsen, Peter E.

    2009-01-01

    While sequence-selective dsDNA targeting by triplex forming oligonucleotides has been studied extensively, only very little is known about the properties of PNA–dsDNA triplexes—mainly due to the competing invasion process. Here we show that when appropriately modified using pseudoisocytosine substitution, in combination with (oligo)lysine or 9-aminoacridine conjugation, homopyrimidine PNA oligomers bind complementary dsDNA targets via triplex formation with (sub)nanomolar affinities (at pH 7....

  19. Thrombin Binding Aptamer, More than a Simple Aptamer: Chemically Modified Derivatives and Biomedical Applications

    OpenAIRE

    Aviñó, Anna Maria; Eritja Casadellà, Ramón; Fàbrega, Carme; Tintoré, María

    2012-01-01

    The thrombin binding aptamer (TBA) is a well characterized chair-like, antiparallel quadruplex structure that binds specifically to thrombin at nanomolar concentrations and therefore it has interesting anticoagulant properties. In this article we review the research involved in the development of new TBA derivatives with improved anticoagulant properties as well as the use of the TBA as a model compound for the study of quadruplex structures. Specifically, we describe the impact of modified n...

  20. Chemically-modified graphene sheets as an active layer for eco-friendly metal electroplating on plastic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Joon-Suk; Hwang, Taeseon; Nam, Gi-Yong; Hong, Jung-Pyo [Department of Polymer Science and Engineering, Sungkyunkwan University, Chunchun-dong, Jangan-gu, Suwon, 440-746 (Korea, Republic of); Bae, Ah-Hyun; Son, Sang-Ik; Lee, Geun-Ho; Sung, Hak kyung [Manufacturing Tech. Center, Samsung Electronics Co., Ltd., Maetan-dong, Yeongtong-gu, Suwon, 443-742 (Korea, Republic of); Choi, Hyouk Ryeol; Koo, Ja Choon [School of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of); Nam, Jae-Do, E-mail: jdnam@skku.edu [Department of Polymer Science and Engineering, Sungkyunkwan University, Chunchun-dong, Jangan-gu, Suwon, 440-746 (Korea, Republic of); Department of Energy Science, Sungkyunkwan University, Suwon (Korea, Republic of)

    2012-10-30

    Eco-friendly nickel (Ni) electroplating was carried out on a plastic substrate using chemically modified graphene sheets as an active and conductive layer to initiate electroplating without using conventional pre-treatment or electroless metal-seeding processes. A graphene oxide (GO) solution was self-assembled on a polyethylene terephthalate (PET) film followed by evaporation to give GO layers (thickness around 6.5 {mu}m) on PET (GO/PET) film. Then, the GO/PET film was chemically and thermally reduced to convert the GO layers to reduced graphene oxide (RGO) layers on the PET substrate. The RGO-coated PET (RGO/PET) film showed the sheet resistance of 100 {Omega} per square. On RGO/PET film, Ni electroplating was conducted under the constant-current condition and the entire surface of the PET film was completely metalized with Ni without any voids.

  1. Physical, chemical and sensory changes in irradiated fresh pork packaged in modified atmosphere

    International Nuclear Information System (INIS)

    The effects of irradiation dose (0, 0.5 and 1.0 kGy), headspace oxygen (0, 10 and 20% O2 balance nitrogen) and storage temperature (5, 15 and 25 degrees C) on the physical, chemical and sensory changes in fresh pork were studied using factorial design experiments. Irradiation in the absence of oxygen extended the sensory shelf life of pork from 9 to 26 days at 5 degrees C and from 2 to 2 days at 25 degrees C. Oxygen in the package headspace combined with irradiation adversely affected physical, chemical and sensory characteristics of the end product

  2. [Research progress in chemical communication among insect-resistant genetically modified plants, insect pests and natural enemies].

    Science.gov (United States)

    Liu, Qing-Song; Li, Yun-He; Chen, Xiu-Ping; Peng, Yu-Fa

    2014-08-01

    Semiochemicals released by plants or insects play an important role in the communication among plants, phytophagous insects and their natural enemies. They thus form a chemical information network which regulates intra- and inter-specific behaviors and sustains the composition and structure of plant and insect communities. The application of insect-resistant genetically modified (IRGM) crops may affect the chemical communication within and among the tritrophic levels, and thus cause disturbances to the biotic community structure and the stability of the farmland ecosystem. This has raised concerns about the environmental safety of IRGM crops and triggered research worldwide. In the current article we provided a brief summary of the chemical communication among plants, herbivores and natural enemies; analyzed the potential of IRGM crops to affect the chemical communication between plants and arthropods and the related mechanisms; and discussed the current research progress and the future prospects in this field. We hope that this will promote the research in this field by Chinese scientists and increase our understanding of the potential effects of growing of IRGM crops on the arthropod community structure.

  3. Chemically Modified Chitosan Beads as Molecularly Imprinted Polymer Matrix for Adsorptive Separation of Proteins

    Institute of Scientific and Technical Information of China (English)

    Tian Ying GUO; Yong Qing XIA; Guang Jie HAO; Bang Hua ZHANG

    2004-01-01

    In a phosphate buffer, a hemoglobin (Hb)-imprinted polymer complex was prepared using maleic anhydride (MAH) modified chitosan beads as matrix, acrylamide (AM) as functional monomer, N,N-methylenebisacrylamide (MBA) as cross-linker and potassiumpersulfate (KPS)/sodium hydrogen sulfite (NaHSO3) as initiators. Langmuir analysis showed that an equal class of adsorption was formed in the molecular imprinting polymer (MIP), and the MIP has high adsorption capacity and selectivity for the imprinted molecule. The MIP can be reused and the recovery was approximately 100% at low concentration.

  4. Structure and Electrical Study of New Chemically Modified Poly(vinyl chloride

    Directory of Open Access Journals (Sweden)

    F. Ammari

    2015-01-01

    Full Text Available The aim of this work was to study the structural and electrical properties of a new polymer obtained by functionalization of a commercial poly(vinyl chloride (PVC (Mw = 48000 by grafting aminoalkyl and aminoaryl groups. Modified poly(vinyl chloride was prepared in two steps. The structural properties of the polymer were systematically investigated by varieties of techniques as differential scanning calorimetric (DSC, thermogravimetry analysis (TG, X-ray diffraction (XRD, and Fourier transform infrared (FTIR spectroscopy. The electrical properties of the polymer were studied by electrochemical impedance spectroscopy (EIS.

  5. Biosorption of stable cesium by chemically modified biomass of Sargassum glaucescens and Cystoseira indica in a continuous flow system

    International Nuclear Information System (INIS)

    Pretreatment of biosorbents have been suggested to modify the surface characteristics which could improve biosorption process. Stable cesium biosorption was studied in continuous fixed-bed column by chemically modified biosorbents. Two kinds of brown algae (Sargassum glaucescens and Cystoseira indica) were treated with chemical agents including formaldehyde (FA), glutaraldehyde (GA), potassium hexacyanoferrate (HCF), FA and HCF, and GA and HCF. The highest biosorption capacity (BC) was obtained from C. indica treated with FA (63.5 mg Cs/g biomass) and S. glaucescens treated with FA and HCF (62 mg Cs/g biomass). To study the effect of the best treatments on the BC, the concentration of each treatment agent was decreased. With decreasing FA agent for C. indica treatment, the BC dropped. Treatment of 1 g S. glaucescens biomass with 2.2 g FA and then 0.18 g HCF resulted in the highest BC (73.08 mg Cs/g dry biomass) which was 35.8 times higher than intact S. glaucescens

  6. Adsorption of hexavalent chromium from synthetic and electroplating effluent on chemically modified Swietenia mahagoni shell in a packed bed column.

    Science.gov (United States)

    Rangabhashiyam, S; Nandagopal, M S Giri; Nakkeeran, E; Selvaraju, N

    2016-07-01

    Packed bed column studies were carried out to evaluate the performance of chemically modified adsorbents for the sequestration of hexavalent chromium from synthetic and electroplating industrial effluent. The effects of parameters such as bed height (3-9 cm), inlet flow rate (5-15 mL/min), and influent Cr(VI) concentration (50-200 mg/L) on the percentage removal of Cr(VI) and the adsorption capacity of the adsorbents in a packed bed column were investigated. The breakthrough time increased with increasing bed height and decreased with the increase of inlet flow rate and influent Cr(VI) concentration. The adsorption column models such as Thomas, Adams-Bohart, Yoon-Nelson, and bed depth service time (BDST) were successfully correlated with the experimental data. The Yoon-Nelson and BDST model showed good agreement with the experimental data for all the studied parameter conditions. Results of the present study indicated that the chemically modified Swietenia mahagoni shell can be used as an adsorbent for the removal of Cr(VI) from industrial wastewater in a packed bed column. PMID:27312254

  7. Thermo-chemical characterization of a Al nanoparticle and NiO nanowire composite modified by Cu powder

    International Nuclear Information System (INIS)

    Highlights: • First study on the copper modified powder-type Al nanoparticle and NiO nanowire composites. • Experimental findings were unique in identifying the AlNi formation and comparing with the Al/CuO thermite. • Potential applications in material joining and bonding. - Abstract: Thermo-chemical properties of the Al nanoparticle and NiO nanowire composites modified by the micro-sized copper additive were investigated experimentally. Their onset temperatures of ignition and energy release data per mass were characterized using differential thermal analysis measurements. These microstructures and chemical compositions of reaction products were analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The fuel-rich Al/NiO/Cu composites produced two types of metallic spheres. Copper spheres were formed from melting and solidification of the copper additive, while AlNi composite spheres were identified by the energy dispersive X-ray spectroscopy and X-ray diffraction analyses. It was found that the amount of the copper additive did not significantly influence the onset temperature of thermite peaks, but caused a dramatic change in energy release. The aforementioned ignition and energetic properties were compared with these from the Al nanoparticle and CuO nanowire composites

  8. Biosorption of stable cesium by chemically modified biomass of Sargassum glaucescens and Cystoseira indica in a continuous flow system

    Energy Technology Data Exchange (ETDEWEB)

    Dabbagh, R. [Nuclear Science Research School, Nuclear Science Technology Research Institute, Tehran (Iran, Islamic Republic of)], E-mail: rdabagh@yahoo.com; Ebrahimi, M.; Aflaki, F.; Ghafourian, H.; Sahafipour, M.H. [Nuclear Science Research School, Nuclear Science Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2008-11-30

    Pretreatment of biosorbents have been suggested to modify the surface characteristics which could improve biosorption process. Stable cesium biosorption was studied in continuous fixed-bed column by chemically modified biosorbents. Two kinds of brown algae (Sargassum glaucescens and Cystoseira indica) were treated with chemical agents including formaldehyde (FA), glutaraldehyde (GA), potassium hexacyanoferrate (HCF), FA and HCF, and GA and HCF. The highest biosorption capacity (BC) was obtained from C. indica treated with FA (63.5 mg Cs/g biomass) and S. glaucescens treated with FA and HCF (62 mg Cs/g biomass). To study the effect of the best treatments on the BC, the concentration of each treatment agent was decreased. With decreasing FA agent for C. indica treatment, the BC dropped. Treatment of 1 g S. glaucescens biomass with 2.2 g FA and then 0.18 g HCF resulted in the highest BC (73.08 mg Cs/g dry biomass) which was 35.8 times higher than intact S. glaucescens.

  9. Thermo-chemical characterization of a Al nanoparticle and NiO nanowire composite modified by Cu powder

    Energy Technology Data Exchange (ETDEWEB)

    Bohlouli-Zanjani, Golnaz [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1 (Canada); Wen, John Z., E-mail: john.wen@uwaterloo.ca [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1 (Canada); Hu, Anming [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1 (Canada); Persic, John [Microbonds Inc., 151 Amber St., Unit 12, Markham, ON L3R 3B3 (Canada); Ringuette, Sophie [Defence Research and Development Canada – Valcartier, 2459 Pie-XI Blvd North, Quebec, QC G3K1Y1 (Canada); Zhou, Y. Norman [Department of Mechanical and Mechatronics Engineering, University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1 (Canada)

    2013-11-20

    Highlights: • First study on the copper modified powder-type Al nanoparticle and NiO nanowire composites. • Experimental findings were unique in identifying the AlNi formation and comparing with the Al/CuO thermite. • Potential applications in material joining and bonding. - Abstract: Thermo-chemical properties of the Al nanoparticle and NiO nanowire composites modified by the micro-sized copper additive were investigated experimentally. Their onset temperatures of ignition and energy release data per mass were characterized using differential thermal analysis measurements. These microstructures and chemical compositions of reaction products were analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The fuel-rich Al/NiO/Cu composites produced two types of metallic spheres. Copper spheres were formed from melting and solidification of the copper additive, while AlNi composite spheres were identified by the energy dispersive X-ray spectroscopy and X-ray diffraction analyses. It was found that the amount of the copper additive did not significantly influence the onset temperature of thermite peaks, but caused a dramatic change in energy release. The aforementioned ignition and energetic properties were compared with these from the Al nanoparticle and CuO nanowire composites.

  10. Enhancing adsorption capacity of toxic malachite green dye through chemically modified breadnut peel: equilibrium, thermodynamics, kinetics and regeneration studies.

    Science.gov (United States)

    Chieng, Hei Ing; Lim, Linda B L; Priyantha, Namal

    2015-01-01

    Breadnut skin, in both its unmodified (KS) and base-modified (BM-KS) forms, was investigated for its potential use as a low-cost adsorbent for the removal of toxic dye, malachite green (MG). Characterization of the adsorbents was carried out using scanning electron microscope, X-ray fluorescence and Fourier transform infra-red spectroscopy. Batch adsorption experiments, carried out under optimized conditions, for the adsorption of MG were fitted using five isotherm models (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Sips) and six error functions to determine the best-fit model. The adsorption capacity was greatly enhanced when breadnut skin was chemically modified with NaOH, leading to an adsorption capacity of 353.0 mg g(-1), that was far superior to most reported adsorbents for the removal of MG. Thermodynamics studies indicated that the adsorption of MG was spontaneous on KS and BM-KS, and the reactions were endothermic and exothermic, respectively. Kinetics studies showed that both followed the pseudo-second order. Regeneration experiments on BM-KS indicated that its adsorption capacity was still maintained at>90% even after five cycles. It can be concluded that NaOH-modified breadfruit skin has great potential to be utilized in real-life application as a low-cost adsorbent for the removal of MG in wastewater treatment.

  11. Thermogravimetric Analysis of Modified Hematite by Methane (CH{sub 4}) for Chemical-Looping Combustion: A Global Kinetics Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Monazam, Esmail R; Breault, Ronald W; Siriwardane, Ranjani; Miller, Duane D

    2013-10-01

    Iron oxide (Fe{sub 2}O{sub 3}) or in its natural form (hematite) is a potential material to capture CO{sub 2} through the chemical-looping combustion (CLC) process. It is known that magnesium (Mg) is an effective methyl cleaving catalyst and as such it has been combined with hematite to assess any possible enhancement to the kinetic rate for the reduction of Fe{sub 2}O{sub 3} with methane. Therefore, in order to evaluate its effectiveness as a hematite additive, the behaviors of Mg-modified hematite samples (hematite –5% Mg(OH){sub 2}) have been analyzed with regard to assessing any enhancement to the kinetic rate process. The Mg-modified hematite was prepared by hydrothermal synthesis. The reactivity experiments were conducted in a thermogravimetric analyzer (TGA) using continuous stream of CH{sub 4} (5, 10, and 20%) at temperatures ranging from 700 to 825 {degrees}C over ten reduction cycles. The mass spectroscopy analysis of product gas indicated the presence of CO{sub 2}, H{sub 2}O, H{sub 2} and CO in the gaseous product. The kinetic data at reduction step obtained by isothermal experiments could be well fitted by two parallel rate equations. The modified hematite samples showed higher reactivity as compared to unmodified hematite samples during reduction at all investigated temperatures.

  12. Biosorption of heavy metals from aqueous solutions by chemically modified orange peel

    International Nuclear Information System (INIS)

    Equilibrium, thermodynamic and kinetic studies were carried out for the biosorption of Pb2+, Cd2+ and Ni2+ ions from aqueous solution using the grafted copolymerization-modified orange peel (OPAA). Langmuir and Freundlich isotherm models were applied to describe the biosorption of the metal ions onto OPAA. The influences of pH and contact time of solution on the biosorption were studied. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. According to the Langmuir equation, the maximum uptake capacities for Pb2+, Cd2+ and Ni2+ ions were 476.1, 293.3 and 162.6 mg g-1, respectively. Compared with the unmodified orange peel, the biosorption capacity of the modified biomass increased 4.2-, 4.6- and 16.5-fold for Pb2+, Cd2+ and Ni2+, respectively. The kinetics for Pb2+, Cd2+ and Ni2+ ions biosorption followed the pseudo-second-order kinetics. The free energy changes (ΔGo) for Pb2+, Cd2+ and Ni2+ ions biosorption process were found to be -3.77, -4.99 and -4.22 kJ mol-1, respectively, which indicates the spontaneous nature of biosorption process. FTIR demonstrated that carboxyl and hydroxyl groups were involved in the biosorption of the metal ions. Desorption of Pb2+, Cd2+ and Ni2+ ions from the biosorbent was effectively achieved in a 0.05 mol L-1 HCl solution.

  13. Catalytic activity of platinum on ruthenium electrodes with modified (electro)chemical states.

    Science.gov (United States)

    Park, Kyung-Won; Sung, Yung-Eun

    2005-07-21

    Using Pt on Ru thin-film electrodes with various (electro)chemical states designed by the sputtering method, the effect of Ru states on the catalytic activity of Pt was investigated. The chemical and electrochemical properties of Pt/Ru thin-film samples were confirmed by X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry. In addition, Pt nanoparticles on Ru metal or oxide for an actual fuel cell system showed an effect of Ru states on the catalytic activity of Pt in methanol electrooxidation. Finally, it was concluded that such an enhancement of methanol electrooxidation on the Pt is responsible for Ru metallic and/or oxidation sites compared to pure Pt without any Ru state. PMID:16852701

  14. The optimal one dimensional periodic table: a modified Pettifor chemical scale from data mining

    Science.gov (United States)

    Glawe, Henning; Sanna, Antonio; Gross, E. K. U.; Marques, Miguel A. L.

    2016-09-01

    Starting from the experimental data contained in the inorganic crystal structure database, we use a statistical analysis to determine the likelihood that a chemical element A can be replaced by another B in a given structure. This information can be used to construct a matrix where each entry (A,B) is a measure of this likelihood. By ordering the rows and columns of this matrix in order to reduce its bandwidth, we construct a one-dimension ordering of the chemical elements, analogous to the famous Pettifor scale. The new scale shows large similarities with the one of Pettifor, but also striking differences, especially in what comes to the ordering of the non-metals.

  15. Mixing in the Amazon estuary

    Science.gov (United States)

    Bezerra, M. O.

    2010-05-01

    The research area of this work is located at the estuary of the Amazon River (Brazil), near the river mouth. The results of air movement analysis on the surface atmospheric circulation over the Mouth of the Amazonas River, salinity and temperature measures as well as measurements of currents, carried out along a longitudinal section in the navigation canal region of the Northern Bar of the Amazon River (Barra Norte do Rio Amazonas) in June 2006, during the river flood season in the quadrature tide. The dynamics effects affect hydrodynamic,meteorological and hydrographical parameters at the river mouth. The conclusion drawn include that: a) the saline wedge-type stratification can be detected approximately 100km away from the mouth of the Amazon River during the end of the rainy season in the quadrature tide; b) probably, at the Amazon estuary the quadrature entrainment processes are dominant and they are the ones responsible for increased salinity detected in the surface layer, whereas turbulence scattering mixing is not so important. c) The large flow of fresh water from the Amazon River at the end of the rainy season implies the displacement of the saline front position over the internal Amazon continental platform, and d) The tidal wave shows a positive asymmetry in the canal, with floods lasting less than in the ebb tide. This asymmetry decreases towards the ocean, eventually becoming reversed in the presence of a saline wedge. The speeds, however, have a negative asymmetry, with more intense ebb tides, due to the river flow and is more evident by the existence of quadrature tides.

  16. Cellular RNA is chemically modified by exposure to air pollution mixtures.

    Science.gov (United States)

    Baldridge, Kevin C; Zavala, Jose; Surratt, Jason; Sexton, Kenneth G; Contreras, Lydia M

    2015-01-01

    RNAs are more susceptible to modifications than DNA, and chemical modifications in RNA have an effect on their structure and function. This study aimed to characterize chemical effects on total RNA in human A549 lung cells after exposure to elevated levels of major secondary air pollutants commonly found in urban locations, including ozone (O3), acrolein (ACR) and methacrolein (MACR). Enzyme-linked immunosorbent assays (ELISA) were used to measure levels of interleukin (IL)-8 in the growth media and 8-oxoguanine (8OG) levels in total cellular RNA, and lactate dehydrogenase (LDH) in the growth media was measured by a coupled enzymatic assay. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure levels of microRNA 10b (miR-10b). The study found that 1-h exposure to all tested pollutant mixtures consistently caused significant increases in the levels of 8OG in total RNA. In the case of 4 ppm O3 exposures, measured levels of IL-8, LDH and miR-10b each showed consistent trends between two independent trials, but varied among these three targets. After 1-h exposures to an ACR+MACR mixture, measured levels of IL-8, LDH and miR-10b showed variable results. For mixtures of O3+ACR+MACR, IL-8 measurements showed no change; miR-10b and LDH showed variable results. The results indicate that short-term high-concentration exposures to air pollution can cause RNA chemical modifications. Chemical modifications in RNAs could represent more consistent markers of cellular stress relative to other inflammation markers, such as IL-8 and LDH, and provide a new biomarker endpoint for mechanistic studies in toxicity of air pollution exposure.

  17. Recognition of RNA duplexes by chemically modified triplex-forming oligonucleotides

    OpenAIRE

    Zhou, Yuan; Kierzek, Elzbieta; Loo, Zi Ping; Antonio, Meraldo; Yau, Yin Hoe; Chuah, York Wieo; Geifman-Shochat, Susana; Kierzek, Ryszard; Chen, Gang

    2013-01-01

    Triplex is emerging as an important RNA tertiary structure motif, in which consecutive non-canonical base pairs form between a duplex and a third strand. RNA duplex region is also often functionally important site for protein binding. Thus, triplex-forming oligonucleotides (TFOs) may be developed to regulate various biological functions involving RNA, such as viral ribosomal frameshifting and reverse transcription. How chemical modification in TFOs affects RNA triplex stability, however, is n...

  18. Radiation chemical and photochemical study of Z-DNA modified by 2-aminopurine and 8- bromodeoxyguanosine

    International Nuclear Information System (INIS)

    DNA is able to take a number of local conformations. (CG) n repeats have the highest potential to Z-DNA which has a left-handed zig-zag backbone and unusual syn-conformation purine base. Because of the polymorphic nature of dinucleotide repeats, it seems possible that Z-DNA forming sequences may provide a source of genetic variation if they occur in regions that are important for the regulation of gene activity. Here, we investigated structural properties of Z-DNA compared with those of B-DNA with respects to one-electron attachment reaction of 8-bromodeoxyguanosine (dBrG) and fluorescence properties of 2-aminopurine (Ap). To investigate one-electron attachment reaction of Z-DNA, we synthesized oligodeoxynucleotides modified by dBrG in which syn-conformation deoxyguanosine was stabilized by steric repulsion between 8-bromo group of dBrG and sugar moiety in Z-DNA. Debromination from the dBrG modified oligodeoxynucleotides occurred from the one-electron attachment during the gamma-ray irradiation. The structural dependence of B- and Z-DNA was observed in the one-electron attachment reaction. Interestingly, the higher conversion of dBrG were observed in the Z-DNA than in the B-DNA. Since the solvent accessibility to purine base in Z-DNA increases compared with that in B-DNA, it is suggested that the electron attachment is enhanced in Z-DNA than in B-DNA. Next we studied the fluorescence properties of Ap in left-handed Z-DNA and compared with those in B-DNA. Since photoexcited adenine analogue Ap can serve as a sensitive probe of DNA structural dynamics, we synthesized Ap- and dBrG-modified oligodeoxynucleotides. Higher intensity was observed in the steady-state fluorescence of Ap in Z-DNA than in B-DNA. A new peak at 275 nm was observed in the excitation spectrum measured at the Ap emission wavelength 370 nm in Z-DNA. This has been explained by the energy transfer from the excited nucleobases to Ap. It is found that Ap is a useful fluorescence probe of Z-DNA

  19. Comparison of Chemical Modifiers for Simultaneous Determination of Different Selenium-Compounds in Serum and Urine by Zeeman-Effect Electrothermal Atomic-Absorption Spectrometry

    DEFF Research Database (Denmark)

    Johannessen, J.K.; Gammelgaard, Bente; Jons, O.;

    1993-01-01

    The thermal stability of selenite, selenate, selenomethionine and trimethylselenonium was studied using different chemical modifiers in various amounts. The normally recommended amounts of nickel nitrate, magnesium nitrate, copper nitrate, copper nitrate mixed with magnesium nitrate, palladium...... equally, while the sensitivity of trimethylselenonium was only 55% using palladium and 85% using palladium and magnesium nitrate. These chemical modifiers were used for the determination of selenium in serum. In aqueous solution, addition of 11 mug of Pd + 1128 mug of Mg(NO3)2 resulted in an equal...... Stabilization of selenite, selenate and trimethylselenonium, while the sensitivity of selenomethionine was 15% higher. This chemical modifier was not applicable to serum and urine, as a white layer accumulated in the graphite tube during the experiments. Using the modifier containing 7.5 mug of Pd + 5 mug of Mg...

  20. High-affinity triplex targeting of double stranded DNA using chemically modified peptide nucleic acid oligomers

    DEFF Research Database (Denmark)

    Hansen, Mads E; Bentin, Thomas; Nielsen, Peter E

    2009-01-01

    While sequence-selective dsDNA targeting by triplex forming oligonucleotides has been studied extensively, only very little is known about the properties of PNA-dsDNA triplexes-mainly due to the competing invasion process. Here we show that when appropriately modified using pseudoisocytosine...... substitution, in combination with (oligo)lysine or 9-aminoacridine conjugation, homopyrimidine PNA oligomers bind complementary dsDNA targets via triplex formation with (sub)nanomolar affinities (at pH 7.2, 150 mM Na(+)). Binding affinity can be modulated more than 1000-fold by changes in pH, PNA oligomer...... length, PNA net charge and/or by substitution of pseudoisocytosine for cytosine, and conjugation of the DNA intercalator 9-aminoacridine. Furthermore, 9-aminoacridine conjugation also strongly enhanced triplex invasion. Specificity for the fully matched target versus one containing single centrally...

  1. Physico-chemical characteristics of nano-organo bentonite prepared using different organo-modifiers

    Directory of Open Access Journals (Sweden)

    A.M. Motawie

    2014-09-01

    Full Text Available Different types of nano-organo bentonite (NOB were prepared from the Egyptian Bentonite (EB. EB was characterized by energy dispersive X-ray EDX. It was purified from different impurities using a conventional method via the treatment with HCl and distilled water. The modification of the clay was carried out using different types of organo-modifiers namely; hexadecyl trimethyl ammonium bromide (HTAB, 3-aminopropyltriethoxysilane (Silane, octadecylamine (ODA, and dodecylamine (DDA. The cation exchange capacity (CEC was measured for pristine bentonite after and before modification. The NB was characterized by FTIR, XRD, TEM, and TGA techniques. The obtained results indicated that variation of the interlayer space gallery was effected by the type of the penetrator used.

  2. Biosorption of heavy metals from aqueous solutions by chemically modified orange peel

    Energy Technology Data Exchange (ETDEWEB)

    Feng Ningchuan [School of Basic Medical Science, Ningxia Medical University, Yinchuan 750004 (China); Guo Xueyi, E-mail: xyguo@mail.csu.edu.cn [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); Liang Sha [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); Zhu Yanshu; Liu Jianping [School of Basic Medical Science, Ningxia Medical University, Yinchuan 750004 (China)

    2011-01-15

    Equilibrium, thermodynamic and kinetic studies were carried out for the biosorption of Pb{sup 2+}, Cd{sup 2+} and Ni{sup 2+} ions from aqueous solution using the grafted copolymerization-modified orange peel (OPAA). Langmuir and Freundlich isotherm models were applied to describe the biosorption of the metal ions onto OPAA. The influences of pH and contact time of solution on the biosorption were studied. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. According to the Langmuir equation, the maximum uptake capacities for Pb{sup 2+}, Cd{sup 2+} and Ni{sup 2+} ions were 476.1, 293.3 and 162.6 mg g{sup -1}, respectively. Compared with the unmodified orange peel, the biosorption capacity of the modified biomass increased 4.2-, 4.6- and 16.5-fold for Pb{sup 2+}, Cd{sup 2+} and Ni{sup 2+}, respectively. The kinetics for Pb{sup 2+}, Cd{sup 2+} and Ni{sup 2+} ions biosorption followed the pseudo-second-order kinetics. The free energy changes ({Delta}G{sup o}) for Pb{sup 2+}, Cd{sup 2+} and Ni{sup 2+} ions biosorption process were found to be -3.77, -4.99 and -4.22 kJ mol{sup -1}, respectively, which indicates the spontaneous nature of biosorption process. FTIR demonstrated that carboxyl and hydroxyl groups were involved in the biosorption of the metal ions. Desorption of Pb{sup 2+}, Cd{sup 2+} and Ni{sup 2+} ions from the biosorbent was effectively achieved in a 0.05 mol L{sup -1} HCl solution.

  3. Investigation of the biofouling properties of several algae on different textured chemical modified silicone surfaces

    International Nuclear Information System (INIS)

    Highlights: • Engineered pillars, pits and grooves spaced 3–12 μm apart were fabricated on siloxane modified acrylic resin films. • The effect of feature size, geometry, and wettability on the settlement of different algae was evaluated. • The feature size and geometry displayed a substantial correlation with the antifouling properties. • A comparatively physical fouling deterrent mechanism was analyzed. - Abstract: Engineered pillars, pits and grooves spaced 3, 6, 9 and 12 μm apart were fabricated on siloxane modified acrylic resin films. The effect of feature size, geometry, and wettability on the settlement of different algae was evaluated. These films showed various antifouling performances to Ulothrix, Closterium and Navicula. For Navicula (length: 10–12 μm), the feature size and geometry displayed a substantial correlation with the antifouling properties. The film with pillars spaced 3 μm reduced Navicula settlement by 73% compared to the control surface. For Closterium (length: 45–55 μm), their responses were governed by the same underlying thermodynamic principles as wettability, the largest reduction in Closterium, 81%, was obtained on the surface with grooves spaced 12 μm apart. For Ulothrix (length: 5–8 mm), the surface also showed the best antifouling performance, the reduction ratio of the settlement on the surface with grooves spaced 12 μm apart could even reach 92%. At last, physical fouling deterrent mechanisms for the films with various textures were analyzed in detail. The feature size and geometry display a substantial correlation with the antifouling properties when the size of fouling algae is close to the textures. With the increasing size for algae, antifouling performance was getting better on surface with pillars or grooves because the algae are bridged between two or more features other than stabilizing its entire mass on one single feature or able to settle between features

  4. Investigation of the biofouling properties of several algae on different textured chemical modified silicone surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jihai [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, Wenjie, E-mail: zhaowj@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Peng, Shusen; Zeng, Zhixiang; Zhang, Xin [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wu, Xuedong, E-mail: xdwu@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Xue, Qunji [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2014-08-30

    Highlights: • Engineered pillars, pits and grooves spaced 3–12 μm apart were fabricated on siloxane modified acrylic resin films. • The effect of feature size, geometry, and wettability on the settlement of different algae was evaluated. • The feature size and geometry displayed a substantial correlation with the antifouling properties. • A comparatively physical fouling deterrent mechanism was analyzed. - Abstract: Engineered pillars, pits and grooves spaced 3, 6, 9 and 12 μm apart were fabricated on siloxane modified acrylic resin films. The effect of feature size, geometry, and wettability on the settlement of different algae was evaluated. These films showed various antifouling performances to Ulothrix, Closterium and Navicula. For Navicula (length: 10–12 μm), the feature size and geometry displayed a substantial correlation with the antifouling properties. The film with pillars spaced 3 μm reduced Navicula settlement by 73% compared to the control surface. For Closterium (length: 45–55 μm), their responses were governed by the same underlying thermodynamic principles as wettability, the largest reduction in Closterium, 81%, was obtained on the surface with grooves spaced 12 μm apart. For Ulothrix (length: 5–8 mm), the surface also showed the best antifouling performance, the reduction ratio of the settlement on the surface with grooves spaced 12 μm apart could even reach 92%. At last, physical fouling deterrent mechanisms for the films with various textures were analyzed in detail. The feature size and geometry display a substantial correlation with the antifouling properties when the size of fouling algae is close to the textures. With the increasing size for algae, antifouling performance was getting better on surface with pillars or grooves because the algae are bridged between two or more features other than stabilizing its entire mass on one single feature or able to settle between features.

  5. UV Spectral Analysis of the Chemical Modification and Photolysis of Acetylacetone Modified Alumina Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    Chengbin JING; Xiujian ZHAO; Haizheng TAO; Xina WANG; Aiyun LIU

    2004-01-01

    Acetylacetone was firstly introduced into the aqueous media with the presence of aluminum sec-butoxide and peptizator. It was confirmed that the UV (ultraviolet) absorption band of acetylacetone underwent 14 nm of red-shift due to the formation of the six-membered ring of the complex between alumina and acetylacetone in the aqueous solution. It was also found that the chemical modification can be dissociated by the UV irradiation with a wavelength shorter than 286 nm as a result of the excitation of π-π* transition in the complex.

  6. Edge Effects on the Electronic Structures of Chemically Modified Armchair Graphene Nanoribbons

    OpenAIRE

    Ren, Hao; Li, Qunxiang; Su, Haibin; Shi, Q. W.; Chen, Jie; Yang, Jinlong

    2007-01-01

    In this paper, we apply the first-principle theory to explore how the electronic structures of armchair graphene nanoribbons (AGNRs) are affected by chemical modifications. The edge addends include H, F, N, NH$_{2}$, and NO$_{2}$. Our theoretical results show that the energy gaps are highly tunable by controlling the widths of AGNRs and addends. The most interesting finding is that N-passivated AGNRs with various widths are metallic due to the unique electronic features of N-N bonds. This pro...

  7. Modifying the effects of fast neutrons in rice seeds by post-treatment with chemical mutagens

    International Nuclear Information System (INIS)

    Dormant rice seeds were exposed to 290-1160 rad of neutrons, dehulled and then soaked in buffered aqueous solutions of either 0.03M EMS or 0.005M MMS for 15h at 30 deg. C. The neutron plus EMS treatment did not affect seedling height and seedset as much as did the neutron plus MMS treatment, which caused marked reductions over those due to neutrons alone. The mutation frequency (Msp) in all neutron doses was slightly to markedly increased by EMS, and reduced by MMS. Neutrons + EMS was found to be an efficient mutagenic combination whereas neutrons + MMS was inefficient (Msp/I). Differences in the synergistic effects of these combined treatments may be due to the specific biological action of the chemicals as determined by their physical properties. An idea that the chemicals may have acted essentially as selective factors for survival of neutron-damage or mutated tiller initials is briefly discussed. (author). 26 refs, 3 tabs

  8. GoAmazon – Scaling Amazon Carbon Water Couplings

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Manvendra Krishna [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-06

    Forests soak up 25% of the carbon dioxide (CO2) emitted by anthropogenic fossil energy use (10 Gt C y-1) moderating its atmospheric accumulation. How this terrestrial CO2 uptake will evolve with climate change in the 21st century is largely unknown. Rainforests are the most active ecosystems with the Amazon basin storing 120 Gt C as biomass and exchanging 18 Gt C y-1 of CO2 via photosynthesis and respiration and fixing carbon at 2-3 kg C m-2 y-1. Furthermore, the intense hydrologic and carbon cycles are tightly coupled in the Amazon where about half of the water is recycled by evapotranspiration and the other half imported from the ocean by Northeasterly trade winds. Climate models predict a drying in the Amazon with reduced carbon uptake while observationally guided assessments indicate sustained uptake. We will resolve this huge discrepancy in the size and sign of the future Amazon carbon cycle by performing the first simultaneous regional scale high frequency measurements of atmospheric CO2, H2O, HOD, CH4, N2O and CO at the T3 site in Manacupuru, Brazil as part of DOE's GoAmazon project. Our data will be used to inform and develop DOE's CLM on the tropical carbon-water couplings at the appropriate grid scale (10-50km). Our measurements will also validate the CO2 data from Japan's GOSAT and NASA's imminent OCO-2 satellite (launch date July 2014).

  9. Comparações entre as propriedades químicas de solos das regiões da floresta amazônica e do cerrado do Brasil Central Comparisons of chemical properties of forest (Amazon region and savanna soils (central region of Brazil

    Directory of Open Access Journals (Sweden)

    J.L.I. Demattê

    1993-09-01

    e para os solos argilosos a muito argilosos, o teor de carbono orgânico é sempre mais elevado na região de cerrado. Não houve diferenças significativas entre o teor de carbono orgânico dos solos com vegetação de cerrado e cerradão. Por outro lado, o teor de carbono orgânico dos latossolos da região Amazônica é mais elevado do que dos PVA.Chemical properties were studied in soil samples from two main fisiographic regions of Brazil: the Amazon region represented by the tropical rain forests and the Brazilian central region represented by the savanna (cerrado vegetation. For this study 17 profiles were selected from the Triângulo Mineiro area: 6 profiles from Goias state, and 5 profiles from the south eastern part of the Mato Grosso State. Most of the profiles are oxisols from medium to clayey texture. For the Amazon region 76 profiles were selected (38 oxisols and 38 ultisols located from Para to Acre States. The following depths were selected: 0-10 cm; 10-40 cm; 40-80 cm and 80-100 cm. The litter layer was not studied. The savanna region has soil in a more advanced weathered stage than the Amazon region. The Ki index of savanna soils varies from 6.0 to 1.5 and of Amazon soils the variation is from 1.3 to 2.5 that included Oxisols (Ki from 1.3 to 2.0 and Ultisols (Ki above 2.0. This indicates that the clay mineralogy of savanna soils is represented by an oxidic mineralogy that is more stable than in the Amazon region represented by a caulinitic mineralogy with 2:1 contribution. The Amazon soils are more acid and present exchangeable At in higher amounts than savanna soils with a direct effect on chemical management. Soils pH correction requires more lime in Amazon soils than in the savanna. The are great differences in both regions between base saturation and pH index. In Amazon soils the pH increase follows the base saturation while this does not occur in savanna soils. In sandy soils the organic carbon is higher in Amazon for all depths studied. In

  10. NOx Direct Decomposition: Potentially Enhanced Thermodynamics and Kinetics on Chemically Modified Ferroelectric Surfaces

    Science.gov (United States)

    Kakekhani, Arvin; Ismail-Beigi, Sohrab

    2014-03-01

    NOx are regulated pollutants produced during automotive combustion. As part of an effort to design catalysts for NOx decomposition that operate in oxygen rich environment and permit greater fuel efficiency, we study chemistry of NOx on (001) ferroelectric surfaces. Changing the polarization at such surfaces modifies electronic properties and leads to switchable surface chemistry. Using first principles theory, our previous work has shown that addition of catalytic RuO2 monolayer on ferroelectric PbTiO3 surface makes direct decomposition of NO thermodynamically favorable for one polarization. Furthermore, the usual problem of blockage of catalytic sites by strong oxygen binding is overcome by flipping polarization that helps desorb the oxygen. We describe a thermodynamic cycle for direct NO decomposition followed by desorption of N2 and O2. We provide energy barriers and transition states for key steps of the cycle as well as describing their dependence on polarization direction. We end by pointing out how a switchable order parameter of substrate,in this case ferroelectric polarization, allows us to break away from some standard compromises for catalyst design(e.g. the Sabatier principle). This enlarges the set of potentially catalytic metals. Primary support from Toyota Motor Engineering and Manufacturing, North America, Inc.

  11. Chemically modified glasses for analysis of hydrogen isotopes by gas chromatography

    International Nuclear Information System (INIS)

    An extensive experimental research has been carried out by gas chromatographic runs in order to identify the most suitable adsorbents and define the best operated conditions for selective separation and analysis of hydrogen isotopes in near real-time (i.e. less than 10 min.). Preparation and operation procedures of chromatographic column for hydrogen isotope separation have been examined. This is one of the main requirements of the tritium separation from heavy water of CANDU reactor and of the tritium fuel cycle in D-T fusion reactors. This paper describes the preparation of absorbent materials utilised as stationary phase in the gas-chromatographic column for hydrogen isotope separation and treatment (activation) of stationary phase. Modified thermoresisting glass with Fe(NH4)2(SO4)2 6H2O and Cr2O3, respectively, have been experimentally investigated at 77 K for H2, HD, and D2 separation and the results of chromatographic runs are also reported and discussed. The hydrogen operating conditions of the adsorbent column Fe (III)/glass and Cr2O3/glass, i.e. granulometry, column length, pressure-drop along the column, carrier gas flow rate, sample volume have been study by means of the analysis of the retention times, separation factors and HETP. (authors)

  12. Amazon Fund: financing deforestation avoidance

    Directory of Open Access Journals (Sweden)

    Jacques Marcovitch

    2014-06-01

    Full Text Available The Amazon Fund, created in 2008 by the Brazilian Federal Government, is managed by Banco Nacional de Desenvolvimento Econômico e Social (BNDES. It is a pioneering initiative to fundraise and manage financial resources to cut back deforestation and support sustainable development for 30 million inhabitants in the Amazon Biome. The Amazon Fund has already received more than R$ 1.7 billion in grants (about USD 787 million. This essay analyzes the Amazon Fund's governance and management with focus on its operation and from its stakeholders' perspectives. A combination of research methods includes: documental research, in-depth interviews, and speech analysis. The study offers a comparative analysis of strengths and weaknesses related to its governance. Furthermore, it proposes ways to improve its management towards greater effectiveness. The essay also includes an assessment of the government of Norway, a major donor to the fund. The governments of Norway and Germany, in partnership with Brazil, reveal how important it is to experiment with new means of international cooperation to successfully reduce greenhouse gas emissions through rainforest preservation.

  13. Monitoring the Amazon plume northwestward transport along Lagrangian pathways

    Science.gov (United States)

    Fournier, Severine; Gaultier, Lucile; Vandemark, Douglas; Lee, Tong; Gierach, Michelle

    2016-04-01

    Large rivers are important to marine air-sea interactions and local biogeochemistry. By modifying the local and regional sea surface salinity (SSS), the freshwater inputs associated with major river plumes cause the formation of a layer near the surface with salinity stratification but near-uniform temperature, known as the barrier layer (BL). The BL prevent exchanges between the warm mixed layer and the cold ocean interior, and thus affect the vertical mixing of heat between the mixed layer and the thermocline. This can have an important impact on air-sea interactions such as hurricanes intensification. Our study focuses on the Amazon and Orinoco rivers, respectively the first and fourth world's largest rivers in terms of discharge. Amazon-Orinoco waters are carried northwestward by the North Brazilian Current (NBC) during the first part of the year and then eastward along the North Equatorial Counter Current. The hurricane season in the tropical Atlantic extends from June through November, the period of Amazon-Orinoco plume maximum northwestward extension, on a hurricane route. Being able to monitor the spatial and temporal dispersal of the Amazon and Orinoco river plumes is therefore important to better understand their impact on barrier layer thickness and SST variation at seasonal to interannual time scales. Variations from year to year in spatial extent of the plume may result from several processes including changes in Amazon discharge, ocean advection, turbulent mixing, and wind field. Satellite remote sensing data provide several means to visualize the surface dispersal of the Amazon plume, with ocean color data being the first to track it in the tropical Atlantic ocean further than 1000 km from shore. With the launches of the ESA Soil Moisture and Ocean Salinity (SMOS) and the NASA Aquarius/SAC-D missions, we are now able to use the SSS observations in combination with ocean color, altimetry and sea surface temperature observations to track surface plume

  14. Applicability of Vacuum Impregnation to Modify Physico-Chemical, Sensory and Nutritive Characteristics of Plant Origin Products—A Review

    Directory of Open Access Journals (Sweden)

    Elżbieta Radziejewska-Kubzdela

    2014-09-01

    Full Text Available Vacuum impregnation is a non-destructive method of introducing a solution with a specific composition to the porous matrices of fruit and vegetables. Mass transfer in this process is a result of mechanically induced differences in pressure. Vacuum impregnation makes it possible to fill large volumes of intercellular spaces in tissues of fruit and vegetables, thus modifying physico-chemical properties and sensory attributes of products. This method may be used, e.g., to reduce pH and water activity of the product, change its thermal properties, improve texture, color, taste and aroma. Additionally, bioactive compounds may be introduced together with impregnating solutions, thus improving health-promoting properties of the product or facilitating production of functional food.

  15. Applicability of vacuum impregnation to modify physico-chemical, sensory and nutritive characteristics of plant origin products--a review.

    Science.gov (United States)

    Radziejewska-Kubzdela, Elżbieta; Biegańska-Marecik, Róża; Kidoń, Marcin

    2014-01-01

    Vacuum impregnation is a non-destructive method of introducing a solution with a specific composition to the porous matrices of fruit and vegetables. Mass transfer in this process is a result of mechanically induced differences in pressure. Vacuum impregnation makes it possible to fill large volumes of intercellular spaces in tissues of fruit and vegetables, thus modifying physico-chemical properties and sensory attributes of products. This method may be used, e.g., to reduce pH and water activity of the product, change its thermal properties, improve texture, color, taste and aroma. Additionally, bioactive compounds may be introduced together with impregnating solutions, thus improving health-promoting properties of the product or facilitating production of functional food. PMID:25244012

  16. Effect of chemically converted graphene as an electrode interfacial modifier on device-performances of inverted organic photovoltaic cells

    International Nuclear Information System (INIS)

    This study examined the effects of chemically converted graphene (CCG) materials as a metal electrode interfacial modifier on device-performances of inverted organic photovoltaic cells (OPVs). As CCG materials for interfacial layers, a conventional graphene oxide (GO) and reduced graphene oxide (rGO) were prepared, and their functions on OPV-performances were compared. The inverted OPVs with CCG materials showed all improved cell-efficiencies compared with the OPVs with no metal/bulk-heterojunction (BHJ) interlayers. In particular, the inverted OPVs with reduction form of GO showed better device-performances than those with GO and better device-stability than poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)-based inverted solar cells, showing that the rGO can be more desirable as a metal/BHJ interfacial material for fabricating inverted-configuration OPVs. (paper)

  17. Interaction of plasma-generated water cluster ions with chemically-modified Si surfaces investigated by infrared absorption spectroscopy

    Directory of Open Access Journals (Sweden)

    Ayumi Hirano-Iwata

    2016-03-01

    Full Text Available We have investigated the interaction of water cluster ions generated by discharge plasma, with chemically modified Si surfaces using infrared absorption spectroscopy in the multiple internal reflection geometry. We observe that water cluster ions readily adsorb on SiO2-covered Si surfaces to form water droplets. We demonstrate that positively- and negatively-charged cluster ions adsorb on the SiO2-covered Si surface in different manners, indicating ionic interaction of the water droplets with the negatively-charged SiO2 surface. Water droplets formed on the protein-coated surface rupture the amide bond of the proteins, suggesting the function of protein decomposition of water cluster ions.

  18. Surface charge, electroosmotic flow and DNA extension in chemically modified thermoplastic nanoslits and nanochannels.

    Science.gov (United States)

    Uba, Franklin I; Pullagurla, Swathi R; Sirasunthorn, Nichanun; Wu, Jiahao; Park, Sunggook; Chantiwas, Rattikan; Cho, Yoon-Kyoung; Shin, Heungjoo; Soper, Steven A

    2015-01-01

    Thermoplastics have become attractive alternatives to glass/quartz for microfluidics, but the realization of thermoplastic nanofluidic devices has been slow in spite of the rather simple fabrication techniques that can be used to produce these devices. This slow transition has in part been attributed to insufficient understanding of surface charge effects on the transport properties of single molecules through thermoplastic nanochannels. We report the surface modification of thermoplastic nanochannels and an assessment of the associated surface charge density, zeta potential and electroosmotic flow (EOF). Mixed-scale fluidic networks were fabricated in poly(methylmethacrylate), PMMA. Oxygen plasma was used to generate surface-confined carboxylic acids with devices assembled using low temperature fusion bonding. Amination of the carboxylated surfaces using ethylenediamine (EDA) was accomplished via EDC coupling. XPS and ATR-FTIR revealed the presence of carboxyl and amine groups on the appropriately prepared surfaces. A modified conductance equation for nanochannels was developed to determine their surface conductance and was found to be in good agreement with our experimental results. The measured surface charge density and zeta potential of these devices were lower than glass nanofluidic devices and dependent on the surface modification adopted, as well as the size of the channel. This property, coupled to an apparent increase in fluid viscosity due to nanoconfinement, contributed to the suppression of the EOF in PMMA nanofluidic devices by an order of magnitude compared to the micro-scale devices. Carboxylated PMMA nanochannels were efficient for the transport and elongation of λ-DNA while these same DNA molecules were unable to translocate through aminated nanochannels. PMID:25369728

  19. Rehabilitation of irradiated patients with chemically modified and conventional SLA implants: five-year follow-up.

    Science.gov (United States)

    Nack, C; Raguse, J-D; Stricker, A; Nelson, K; Nahles, S

    2015-01-01

    The aim of this study is to evaluate the clinical and radiological parameters of standard SLA surface implants compared to chemically modified hydrophilic SLActive implants in irradiated patients after the initial 12-month loading period up to 5 years. Twenty patients with a mean age of 61·1 years were treated with dental implants after ablative surgery and radio-chemotherapy of oral cancer. All patients were non-smokers. The placement of 102 implants (50 SLA, 52 SLActive) was performed bilaterally according to a split-mouth design. Mean crestal bone changes were evaluated using standardised orthopantomographies and clinical parameters. Data were analysed using a Kaplan-Meier curve, Mann-Whitney U-test and two-factorial non-parametric analysis. The average observation period was 60 months. The amount of bone loss at the implant shoulder of SLA implants was mesial and distal 0·7 mm. The SLActive implants displayed a bone loss of mesial 0·6 mm as well as distal 0·7 mm after 5 years. Two SLA implants were lost before loading. One patient lost five implants due to recurrence of a tumour. The overall cumulative 12-month, 3-year and 5-year survival rate of SLA implants was 92%, 80% and 75·8% and of SLActive implants 94·2%, 78·8% and 74·4%, respectively. Eighteen implants were considered lost because the patients had died. Sandblasted acid-etched implants with or without a chemically modified surface can be used in irradiated patients with a high predictability of success. Lower implant survival rates in patients with irradiated oral cancer may be associated with systemic effects rather than peri-implantitis.

  20. Fabrication and characterization of indium sulfide thin films deposited on SAMs modified substrates surfaces by chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Meng Xu [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou, 730050 (China); Lu Yongjuan; Zhang Xiaoliang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Graduate School of Chinese Academy of Sciences, Beijing, 10049 (China); Yang Baoping [College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou, 730050 (China); Yi Gewen [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Jia Junhong, E-mail: jhjia@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

    2011-11-01

    In an effort to explore the optoelectronic properties of nanostructured indium sulfide (In{sub 2}S{sub 3}) thin films for a wide range of applications, the In{sub 2}S{sub 3} thin films were successfully deposited on the APTS layers (-NH{sub 2}-terminated) modified ITO glass substrates using the chemical bath deposition technique. The surface morphology, structure and composition of the resultant In{sub 2}S{sub 3} thin films were characterized by FESEM, XRD, and XPS, respectively. Also, the correlations between the optical properties, photocurrent response and the thickness of thin films were established. According to the different deposition mechanisms on the varying SAMs terminational groups, the positive and negative micropatterned In{sub 2}S{sub 3} thin films were successfully fabricated on modified Si substrates surface combining with the ultraviolet lithography process. This offers an attractive opportunity to fabricate patterned In{sub 2}S{sub 3} thin films for controlling the spatial positioning of functional materials in microsystems.

  1. A reagentless enzymatic fluorescent biosensor for glucose based on upconverting glasses, as excitation source, and chemically modified glucose oxidase.

    Science.gov (United States)

    Del Barrio, Melisa; Cases, Rafael; Cebolla, Vicente; Hirsch, Thomas; de Marcos, Susana; Wilhelm, Stefan; Galbán, Javier

    2016-11-01

    Upon near-infrared excitation Tm(3+)+Yb(3+) doped fluorohafnate glasses present upconversion properties and emit visible light. This property permits to use these glasses (UCG) as excitation sources for fluorescent optical biosensors. Taking this into account, in this work a fluorescent biosensor for glucose determination is designed and evaluated. The biosensor combines the UCG and the fluorescence of the enzyme glucose oxidase chemically modified with a fluorescein derivative (GOx-FS), whose intensity is modified during the enzymatic reaction with glucose. Optical parameters have been optimized and a mathematical model describing the behavior of the analytical signal is suggested. Working in FIA mode, the biosensor responds to glucose concentrations up to, at least, 15mM with a limit of detection of 1.9mM. The biosensor has a minimum lifetime of 9 days and has been applied to glucose determination in drinks. The applicability of the sensor was tested by glucose determination in two fruit juices. PMID:27591654

  2. Seroprevalence of Toxoplasma gondii in free-living Amazon River dolphins (Inia geoffrensis) from central Amazon, Brazil.

    Science.gov (United States)

    Santos, P S; Albuquerque, G R; da Silva, V M F; Martin, A R; Marvulo, M F V; Souza, S L P; Ragozo, A M A; Nascimento, C C; Gennari, S M; Dubey, J P; Silva, J C R

    2011-12-29

    Toxoplasma gondii is an important pathogen in aquatic mammals and its presence in these animals may indicate the water contamination of aquatic environment by oocysts. Serum samples from 95 free-living Amazon River dolphins (Inia geoffrensis) from the Mamirauá Sustainable Development Reserve (RDSM), Tefé, Amazonas, Central Amazon, Brazil were tested for T. gondii antibodies using the modified agglutination test (MAT). Antibodies (MAT ≥ 25) to T. gondii were found in 82 (86.3%) dolphins with titers of 1:25 in 24, 1:50 in 56, and 1:500 in 2. Results suggest a high level contamination of the aquatic environment of the home range of these animals. PMID:21764516

  3. Biomimetic Deposition of Apatite on Surface Chemically Modified Porous NiTi Shapememory Alloy

    Science.gov (United States)

    Wu, S. L.; Liu, X. M.; Chung, C. Y.; Chu, Paul K.; Chan, Y. L.; Yeung, K. W. K.; Chu, C. L.

    Porous NiTi shape memory alloy (SMA) with 48% porosity and an average pore size of 50-800 μm was synthesized by capsule-free hot isostatic pressing (CF-HIP). To enhance the surface bioactivity, the porous NiTi SMA was subjected to H2O2 and subsequent NaOH treatment. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analyses revealed that a porous sodium titanate (Na2TiO3) film had formed on the surface of the porous NiTi SMA. An apatite layer was deposited on this film after immersion in simulated body fluid at 37°C, while no apatite could be found on the surface of the untreated porous NiTi SMA. The formation of the apatite layer infers that the bioactivity of the porous NiTi SMA may be enhanced by surface chemical treatment, which is favorable for its application as bone implants.

  4. Synthesis and Self-Assembly of Gold Nanoparticles by Chemically Modified Polyol Methods under Experimental Control

    International Nuclear Information System (INIS)

    In our present research, bottom-up self-assembly of gold (Au) nanoparticles on a flat copper (Cu) substrate is performed by a facile method. The very interesting evidence of self-assembly of Au nanoparticles on the top of the thin assembled layer was observed by scanning electron microscopy (SEM). We had discovered one of the most general and simple methods for the self-assembly of metal nanoparticles. The general physical and chemical mechanisms of the evaporation process of the solvents can be used for self-assembly of the as-prepared nanoparticles. The important roles of molecules of the used solvents are very critical to self-assembly of the as-prepared Au nanoparticles in the case without using any polymers for those processes. It is clear that self-assembly of such one nano system of the uniform Au nanoparticles is fully examined. Finally, an exciting surface plasmon resonance (SPR) phenomenon of the pure Au nanoparticles in the solvent was fully discovered in their exciting changes of the narrow and large SPR bands according to synthesis time. The SPR was considered as the collective oscillation of valence electrons of the surfaces of the pure Au nanoparticles in the solvent by incident ultraviolet-visible light. Then, the frequency of light photons matches the frequency of the oscillation of surface electrons of the Au nanoparticles that are excited.

  5. The chemical synthesis of α-conotoxins and structurally modified analogs with enhanced biological stability.

    Science.gov (United States)

    Banerjee, Jayati; Gyanda, Reena; Chang, Yi-Pin; Armishaw, Christopher J

    2013-01-01

    α-Conotoxins are peptide neurotoxins isolated from the venom ducts of carnivorous marine cone snails that exhibit exquisite pharmacological potency and selectivity for various nicotinic acetylcholine receptor subtypes. As such, they are important research tools and drug leads for treating various diseases of the central nervous system, including pain and tobacco addiction. Despite their therapeutic potential, the chemical synthesis of α-conotoxins for use in structure-activity relationship studies is complicated by the possibility of three disulfide bond isomers, where inefficient folding methods can lead to a poor recovery of the pharmacologically active isomer. In order to achieve higher yields of the native isomer, especially in high-throughput syntheses it is necessary to select appropriate oxidative folding conditions. Moreover, the poor biochemical stability exhibited by α-conotoxins limits their general therapeutic applicability in vivo. Numerous strategies to enhance their stability including the substitution of disulfide bond with diselenide bond and N-to-C cyclization via an oligopeptide spacer have successfully overcome these limitations. This chapter describes methods for performing both selective and nonselective disulfide bond oxidation strategies for controlling the yields and formation of α-conotoxin disulfide bond isomers, as well as methods for the production of highly stable diselenide-containing and N-to-C cyclized conotoxin analogs. PMID:24014431

  6. Enhanced compatibility of chemically modified titanium surface with periodontal ligament cells

    Science.gov (United States)

    Kado, T.; Hidaka, T.; Aita, H.; Endo, K.; Furuichi, Y.

    2012-12-01

    A simple chemical modification method was developed to immobilize cell-adhesive molecules on a titanium surface to improve its compatibility with human periodontal ligament cells (HPDLCs).The polished titanium disk was immersed in 1% (v/v) p-vinylbenzoic acid solution for 2 h to introduce carboxyl groups onto the surface. After rinsing with distilled deionized water, the titanium disk was dipped into 1.47% 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide solution containing 0.1 mg/ml Gly-Arg-Gly-Asp-Ser (GRGDS), human plasma fibronectin (pFN), or type I collagen from calf skin (Col) to covalently immobilize the cell-adhesive molecules on the titanium surface via formation of peptide bonds. X-ray photoelectron spectroscopy analyses revealed that cell-adhesive molecules were successfully immobilized on the titanium surfaces. The Col-immobilized titanium surface revealed higher values regarding nano rough characteristics than the as-polished titanium surface under scanning probe microscopy. The number of HPDLCs attached to both the pFN- and Col-immobilized titanium surfaces was twice that attached to the as-polished titanium surfaces. The cells were larger with the cellular processes that stretched to a greater extent on the pFN- and Col-immobilized titanium surfaces than on the as-polished titanium surface (p < 0.05). HPDLCs on the Col-immobilized titanium surfaces showed more extensive expression of vinculin at the tips of cell projections and more contiguously along the cell outline than on the as-polished, GRGDS-immobilized and pFN-immobilized titanium surfaces. It was concluded that cell-adhesive molecules successfully immobilized on the titanium surface and improved the compatibility of the surface with HPDLCs. The Col-immobilized titanium surface could be used for forming ligament-like tissues around titanium dental implants.

  7. Phase Stability of Ce-Modified La2Zr2O7 Coatings and Chemical Compatibility with YSZ

    Science.gov (United States)

    Wu, Qiong; Ji, Xiaojuan; Peng, Haoran; Ren, Xianjing; Yu, Yueguang

    2016-04-01

    Ce-modified La2Zr2O7 powders, i.e., La2Zr2O7 (LZ), La2(Zr0.7Ce0.3)2O7 (LZ7C3), and La2(Zr0.3Ce0.7)2O7 (LZ3C7), were used to produce thermal barrier coatings by atmospheric plasma spray process. The chemical compatibility of the CeO2-doped La2Zr2O7 with the traditional YSZ was investigated in LZ-YSZ powder mixtures and LZ-YSZ bilayer coatings by x-ray diffraction and scanning electron microscope. The powder mixtures and coatings were aged at 1200 and 1300 °C for 100 h. The results showed that LZ and LZ7C3 presented single pyrochlore structure after the heat treatments at both 1200 and 1300 °C. For LZ3C7, however, fluorite structure was observed at 1300 °C, indicating a poor phase stability of LZ3C7 at the elevated temperature. The results further showed that La2(Zr0.3Ce0.7)2O7 reacted with YSZ in the bilayer ceramic coatings due to the diffusion of cerium, zirconium, and yttrium. While for La2Zr2O7(LZ) and La2(Zr0.7Ce0.3)2O7, a better chemical compatibility with YSZ was shown.

  8. A genotype of modified vaccinia Ankara (MVA) that facilitates replication in suspension cultures in chemically defined medium.

    Science.gov (United States)

    Jordan, Ingo; Horn, Deborah; John, Katrin; Sandig, Volker

    2013-01-21

    While vectored vaccines, based on hyperattenuated viruses, may lead to new treatment options against infectious diseases and certain cancers, they are also complex products and sometimes difficult to provide in sufficient amount and purity. To facilitate vaccine programs utilizing host-restricted poxviruses, we established avian suspension cell lines (CR and CR.pIX) and developed a robust, chemically defined, culturing process for production of this class of vectors. For one prominent member, modified vaccinia Ankara (MVA), we now describe a new strain that appears to replicate to greater yields of infectious units, especially in the cell-free supernatant of cultures in chemically defined media. The new strain was obtained by repeated passaging in CR suspension cultures and, consistent with reports on the exceptional genetic stability of MVA, sequencing of 135 kb of the viral genomic DNA revealed that only three structural proteins (A3L, A9L and A34R) each carry a single amino acid exchange (H639Y, K75E and D86Y, respectively). Host restriction in a plaque-purified isolate of the new genotype appears to be maintained in cell culture. Processing towards an injectable vaccine preparation may be simplified with this strain as a complete lysate, containing the main burden of host cell contaminants, may not be required anymore to obtain adequate yields.

  9. A chemically modified [alpha]-amylase with a molten-globule state has entropically driven enhanced thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, Khawar Sohail; Poljak, Anne; De Francisci, Davide; Guerriero, Gea; Pilak, Oliver; Burg, Dominic; Raftery, Mark J.; Parkin, Don M.; Trewhella, Jill; Cavicchioli, Ricardo (Sydney); (New South)

    2010-11-15

    The thermostability properties of TAA were investigated by chemically modifying carboxyl groups on the surface of the enzyme with AMEs. The TAA{sub MOD} exhibited a 200% improvement in starch-hydrolyzing productivity at 60 C. By studying the kinetic, thermodynamic and biophysical properties, we found that TAA{sub MOD} had formed a thermostable, MG state, in which the unfolding of the tertiary structure preceded that of the secondary structure by at least 20 C. The X-ray crystal structure of TAA{sub MOD} revealed no new permanent interactions (electrostatic or other) resulting from the modification. By deriving thermodynamic activation parameters of TAA{sub MOD}, we rationalised that thermostabilisation have been caused by a decrease in the entropy of the transition state, rather than being enthalpically driven. Far-UV CD shows that the origin of decreased entropy may have arisen from a higher helical content of TAA{sub MOD}. This study provides new insight into the intriguing properties of an MG state resulting from the chemical modification of TAA.

  10. Electron Transfer Reactivity Patterns at Chemically Modified Electrodes: Fundamentals and Application to the Optimization of Redox Recycling Amplification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Bergren, Adam Johan [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    Electroanalytical chemistry is often utilized in chemical analysis and Fundamental studies. Important advances have been made in these areas since the advent of chemically modified electrodes: the coating of an electrode with a chemical film in order to impart desirable, and ideally, predictable properties. These procedures enable the exploitation of unique reactivity patterns. This dissertation presents studies that investigate novel reaction mechanisms at self-assembled monolayers on gold. In particular, a unique electrochemical current amplification scheme is detailed that relies on a selective electrode to enable a reactivity pattern that results in regeneration of the analyte (redox recycling). This regenerating reaction can occur up to 250 times for each analyte molecule, leading to a notable enhancement in the observed current. The requirements of electrode selectivity and the resulting amplification and detection limit improvements are described with respect to the heterogeneous and homogeneous electron transfer rates that characterize the system. These studies revealed that the heterogeneous electrolysis of the analyte should ideally be electrochemically reversible, while that for the regenerating agent should be held to a low level. Moreover, the homogeneous reaction that recycles the analyte should occur at a rapid rate. The physical selectivity mechanism is also detailed with respect to the properties of the electrode and redox probes utilized. It is shown that partitioning of the analyte into/onto the adlayer leads to the extraordinary selectivity of the alkanethiolate monolayer modified electrode. Collectively, these studies enable a thorough understanding of the complex electrode mechanism required for successful redox recycling amplification systems, Finally, in a separate (but related) study, the effect of the akyl chain length on the heterogeneous electron transfer behavior of solution-based redox probes is reported, where an odd-even oscillation

  11. Enhanced compatibility of chemically modified titanium surface with periodontal ligament cells

    Energy Technology Data Exchange (ETDEWEB)

    Kado, T.; Hidaka, T. [Division of Periodontology and Endodontology, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293 (Japan); Aita, H. [Division of Occlusion and Removable Prosthodontics, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293 (Japan); Endo, K. [Division of Biomaterials and Bioengineering, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293 (Japan); Furuichi, Y., E-mail: furuichi@hoku-iryo-u.ac.jp [Division of Periodontology and Endodontology, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, 1757 Kanazawa, Ishikari-Tobetsu, Hokkaido 061-0293 (Japan)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer Cell-adhesive molecules were covalently immobilized on a Ti surface. Black-Right-Pointing-Pointer Immobilized cell-adhesive molecules maintained native function on the Ti surface. Black-Right-Pointing-Pointer Immobilized collagen enhanced adhesion of periodontal ligament cells to the Ti. - Abstract: A simple chemical modification method was developed to immobilize cell-adhesive molecules on a titanium surface to improve its compatibility with human periodontal ligament cells (HPDLCs).The polished titanium disk was immersed in 1% (v/v) p-vinylbenzoic acid solution for 2 h to introduce carboxyl groups onto the surface. After rinsing with distilled deionized water, the titanium disk was dipped into 1.47% 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide solution containing 0.1 mg/ml Gly-Arg-Gly-Asp-Ser (GRGDS), human plasma fibronectin (pFN), or type I collagen from calf skin (Col) to covalently immobilize the cell-adhesive molecules on the titanium surface via formation of peptide bonds. X-ray photoelectron spectroscopy analyses revealed that cell-adhesive molecules were successfully immobilized on the titanium surfaces. The Col-immobilized titanium surface revealed higher values regarding nano rough characteristics than the as-polished titanium surface under scanning probe microscopy. The number of HPDLCs attached to both the pFN- and Col-immobilized titanium surfaces was twice that attached to the as-polished titanium surfaces. The cells were larger with the cellular processes that stretched to a greater extent on the pFN- and Col-immobilized titanium surfaces than on the as-polished titanium surface (p < 0.05). HPDLCs on the Col-immobilized titanium surfaces showed more extensive expression of vinculin at the tips of cell projections and more contiguously along the cell outline than on the as-polished, GRGDS-immobilized and pFN-immobilized titanium surfaces. It was concluded that cell-adhesive molecules successfully

  12. Enhancement of uranium(VI) biosorption by chemically modified marine-derived mangrove endophytic fungus Fusarium sp. ZZF51

    International Nuclear Information System (INIS)

    Fusarium sp. ZZF51, mangrove endophytic fungus originated from South China Sea coast, was chemically modified by formaldehyde, methanol and acetic acid to enhance its affinity of uranium(VI) from waste water. The influencing factors about uranium(VI) adsorption such as contact time, solution pH, the ratio of solid/liquid (S/L) and initial uranium(VI) concentration were investigated, and the suitable adsorption isotherm and kinetic models were determined. In addition, the biosorption mechanism was also discussed by FTIR analysis. Experimental results show that the maximum biosorption capacity of formaldehyde-treated biomass for uranium(VI) at the optimized condition of pH 6.0, S/L 0.6 and equilibrium time 90 min is 318.04 mg g-1, and those of methanol-treated and HAc-treated biomass are 311.95 and 351.67 mg g-1 at the same pH and S/L values but different equilibrium time of 60 and 90 min, respectively. Thus the maximum biosorption capacity of the three kind of modified biomass have greatly surpassed that of the raw biomass (21.42 mg g-1). The study of kinetic exhibits a high level of compliance with the Lagergren's pseudo-second-order kinetic models. Langumir and Freundlich models have proved to be well able to explain the sorption equilibrium with the satisfactory correlation coefficients higher than 0.96. FTIR analysis reveals that the carboxyl, amino and hydroxyl groups on the cell wall of Fusarium sp. ZZF51 play an important role in uranium(VI) biosorption process. (author)

  13. Cobalt as chemical modifier to improve chromium sensitivity and minimize matrix effects in tungsten coil atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Sidnei G. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P.O. Box 676, São Carlos, SP 13560-970 (Brazil); Donati, George L., E-mail: georgedonati@yahoo.com.br [Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109 (United States); Santos, Luana N. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P.O. Box 676, São Carlos, SP 13560-970 (Brazil); Jones, Bradley T. [Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109 (United States); Nóbrega, Joaquim A. [Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P.O. Box 676, São Carlos, SP 13560-970 (Brazil)

    2013-05-30

    Graphical abstract: -- Highlights: •Charge transfer reactions increase the population of Cr{sup +}. •Chromium ions and electrons recombine to form excited-state Cr atoms. •A 10-fold improvement in LOD is observed for Cr emission measurements. •The two-step ionization/excitation mechanism improves sensitivity and accuracy. •High concentrations of Co also minimize matrix effects. -- Abstract: Cobalt is used as chemical modifier to improve sensitivity and minimize matrix effects in Cr determinations by tungsten coil atomic emission spectrometry (WCAES). The atomizer is a tungsten filament extracted from microscope light bulbs. A solid-state power supply and a handheld CCD-based spectrometer are also used in the instrumental setup. In the presence of 1000 mg L{sup −1} Co, WCAES limit of detection for Cr (λ = 425.4 nm) is calculated as 0.070 mg L{sup −1}; a 10-fold improvement compared to determinations without Co modifier. The mechanism involved in such signal enhancement is similar to the one observed in ICP OES and ICP-MS determinations of As and Se in the presence of C. Cobalt increases the population of Cr{sup +} by charge transfer reactions. In a second step, Cr{sup +}/e{sup −} recombination takes place, which results in a larger population of excited-state Cr atoms. This alternative excitation route is energetically more efficient than heat transfer from atomizer and gas phase to analyte atoms. A linear dynamic range of 0.25–10 mg L{sup −1} and repeatability of 3.8% (RSD, n = 10) for a 2.0 mg L{sup −1} Cr solution are obtained with this strategy. The modifier high concentration also contributes to improving accuracy due to a matrix-matching effect. The method was applied to a certified reference material of Dogfish Muscle (DORM-2) and no statistically significant difference was observed between determined and certified Cr values at a 95% confidence level. Spike experiments with bottled water samples resulted in recoveries between 93% and

  14. Caracterização física e química de terras pretas arqueológicas e de solos não antropogênicos na região de Manicoré, Amazonas = Physical and chemical characterization of archaeological dark earths and nonanthropogenic soils the Manicore region, Amazon.

    Directory of Open Access Journals (Sweden)

    Marcelo Dayron Rodrigues Soares

    2012-08-01

    Full Text Available Os solos predominantes na região Amazônica pertencem à classe dos Latossolos e Argissolos, caracterizado por seu alto grau de intemperismo e baixa fertilidade natural, em contraste, ocorrem às terras pretas arqueológicas com elevada fertilidade natural e alto teor de matéria orgânica. Objetivou-se com este estudo caracterizar quanto aos atributos físicos e químicos as terras pretas arqueológicas e os solos não antropogênicos da região de Manicoré, AM. Foram amostrados quatro sítios de Terras Pretas Arqueológicas e quatro solos não antropogênicos distribuídos na região de Manicoré, sul do Amazonas. Nesses locais foram abertas trincheiras e os perfis foram caracterizados morfologicamente e coletados por horizonte. Foramrealizadas análises físicas (textura e densidade do solo e químicas (pH em água, Ca, Mg, K, e Al trocáveis, P disponível, e C orgânico. Os valores de pH, carbono orgânico, soma de bases e V% das terras pretas arqueológicas foram superiores aos observados para solos não antropogênicos da região de Manicoré, AM. Os solos não antropogênicos apresentaram maiores valores de densidade do solo quando comparados às áreas de terra preta arqueológica. Os maiores teores de matéria orgânica do solo foram encontrados nas áreas de terra preta arqueológica. As terras pretas arqueológicas deste estudo apresentam atributos químicos e físico-químicos superiores aos solos não antropogênicos, conferindo-lhes maior fertilidade.The predominant soils in the Amazon region belong to the class of Oxisols and Ultisols, characterized by its high degree of weathering and low natural fertility, in contrast, occur at Archaeological Dark Earths soils with high fertility and high organic matter content. The aim of this study was the physical and chemical characterization of archaeological dark earths and non-anthropogenic soils in the southern Amazon. Four archaeological sites with dark earths and four non

  15. Chemically modified ion-sensitive field-effect transistors: elimination of the liquid juction potential in a double sensor flow-injection analysis cell

    NARCIS (Netherlands)

    Cobben, Peter L.H.M.; Egberink, Richard J.M.; Bomer, J.G.; Schouwenaar, Robert; Brzozka, Zbigniew; Bergveld, Piet; Reinhoudt, David N.; Bos, Martinus

    1993-01-01

    A flow-through cell was designed that can be used for flow-injection analysis with two chemically modified ion-sensitive field-effect transistors (CHEMFETs) in close proximity. This offers the possibility of a differential measurement without influence of the liquid junction potential. The different

  16. Comparison of adsorption of Cd(II and Pb(II ions on pure and chemically modified fly ashes

    Directory of Open Access Journals (Sweden)

    Sočo Eleonora

    2016-06-01

    Full Text Available The study investigates chemical modifications of coal fly ash (FA treated with HCl or NH4HCO3 or NaOH or Na2edta, based on the research conducted to examine the behaviour of Cd(II and Pb(II ions adsorbed from water solution on treated fly ash. In laboratory tests, the equilibrium and kinetics were examined applying various temperatures (293 - 333 K and pH (2 - 11 values. The maximum Cd(II and Pb(II ions adsorption capacity obtained at 293 K, pH 9 and mixing time 2 h from the Langmuir model can be grouped in the following order: FA-NaOH > FA-NH4HCO3 > FA > FA-Na2edta > FA-HCl. The morphology of fly ash grains was examined via small-angle X-ray scattering (SAXS and images of scanning electron microscope (SEM. The adsorption kinetics data were well fitted by a pseudo-second-order rate model but showed a very poor fit for the pseudofirst order model. The intra-particle model also revealed that there are two separate stages in the sorption process, i.e. the external diffusion and the inter-particle diffusion. Thermodynamics parameters such as free energy, enthalpy and entropy were also determined. A laboratory test demonstrated that the modified coal fly ash worked well for the Cd(II and Pb(II ion uptake from polluted waters.

  17. Physical characteristics of chemically modified starch from potatoes, evaluated by X-ray diffraction, SEM and NMR

    International Nuclear Information System (INIS)

    The aim of this study was to compare the physical characteristics of chemically modified starch by cross-linking and methylation in order to observe the changes occurred in the molecule which could give it a positive and specific application. The physical characteristics were evaluated by morphometric analysis using analytical methods as scanning electron microscopy, x-ray diffraction and nuclear magnetic resonance in solid state. The results point for all the evaluated characteristics that the cross-linked starch from potato maintains a granular size and shape similar to native starch, through some granules were affected since they presented cracks and outlet of internal material; the introduction of phosphate groups in the molecule is evident in the NMR spectra: the methylated starch from potato changed in a drastic way the structure of granules since the size increased from 9 to 53 μm of the native starch to 44 to 181 μm for the methylated, the X-ray spectra shows a formation of crystals, banishing the characteristic standard type B, likewise with NMR a modification of starch was observed due to the presence of methyl groups. (Author)

  18. COL-3, a chemically modified tetracycline, inhibits lipopolysaccharide-induced microglia activation and cytokine expression in the brain.

    Science.gov (United States)

    Edan, Rawan Abdulhameed; Luqmani, Yunus A; Masocha, Willias

    2013-01-01

    Microglia activation results in release of proinflammatory molecules including cytokines, which contribute to neuronal damage in the central nervous system (CNS) if not controlled. Tetracycline antibiotics such as minocycline inhibit microglial activation and cytokine expression during CNS inflammation. In the present study we found that administration of chemically modified tetracycline-3 (COL-3), inhibits lipopolysaccharide (LPS)-induced microglial and p38 MAPK activation, as well as the increase in TNF-α, but not IL-1β expression, in the brains of BALB/c mice. COL-3 has been described to have no antibacterial activity. We observed that COL-3 had no activity against a Gram-negative bacteria, Escherichia coli; however surprisingly, COL-3 had antibacterial activity against a Gram-positive bacteria Staphylococcus aureus, with a minimum inhibitory concentration of 1 mg/ml. Our data show that COL-3 has some antibacterial activity against S. aureus, inhibits LPS-induced neuroinflammation, and displays potential as a therapeutic agent for treatment of conditions involving CNS inflammation.

  19. Optical properties of carbon nanostructures produced by laser irradiation on chemically modified multi-walled carbon nanotubes

    Science.gov (United States)

    Santiago, Enrique Vigueras; López, Susana Hernández; Camacho López, Marco A.; Contreras, Delfino Reyes; Farías-Mancilla, Rurik; Flores-Gallardo, Sergio G.; Hernández-Escobar, Claudia A.; Zaragoza-Contreras, E. Armando

    2016-10-01

    This research focused on the nanosecond (Nd: YAG-1064 nm) laser pulse effect on the optical and morphological properties of chemically modified multi-walled carbon nanotubes (MWCNT). Two suspensions of MWCNT in tetrahydrofuran (THF) were prepared, one was submitted to laser pulses for 10 min while the other (blank) was only mechanically homogenized during the same time. Following the laser irradiation, the suspension acquired a yellow-amber color, in contrast to the black translucent appearance of the blank. UV-vis spectroscopy confirmed this observation, showing the blank a higher absorption. Additionally, photoluminescence measurements exhibited a broad blue-green emission band both in the blank and irradiated suspension when excited at 369 nm, showing the blank a lower intensity. However, a modification in the excitation wavelength produced a violet to green tuning in the irradiated suspension, which did not occur in the blank. Lastly, the electron microscopy analysis of the treated nanotubes showed the abundant formation of amorphous carbon, nanocages, and nanotube unzipping, exhibiting the intense surface modification produced by the laser pulse. Nanotube surface modification and the coexistence with the new carbon nanostructures were considered as the conductive conditions for optical properties modification.

  20. Transcriptionally active and inactive genes are similarly modified by chemical carcinogens or X-ray in normal human fibroblasts

    International Nuclear Information System (INIS)

    Chemical carcinogens and ionizing radiation induce DNA modifications and strand breaks in cells. This damage is reported to be affected by chromatin proteins or chromatin of a higher structure order. To compare the sensitivity of transcriptionally active and inactive genes on chromatin toward DNA-damaging agents, we treated normal human fibroblasts (WI-38) cells with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), X-ray, 4-hydroxyaminoquinoline 1-oxide or N-acetoxy-2-acetylaminofluorene, and high molecular weight DNA was isolated. After digestion with EcoRI to completion, the DNA was electrophoresed on an alkaline agarose gel, blotted on a nitrocellulose filter and hybridized with a transcriptionally active gene probe (human type I(α2) procollagen gene) or an inactive gene probe (human β-globin gene). The results show that both genes are similarly modified by these agents. Repair of DNA damage caused by MNNG also occurred similarly in collagen and β-globin genes after removal of MNNG. (Auth.)

  1. Glassy carbon electrode modified with a graphene oxide/poly(o-phenylenediamine) composite for the chemical detection of hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Van Hoa [School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 712-749 (Korea, Republic of); Department of Chemistry, Nha Trang University, 2 Nguyen Dinh Chieu, Nha Trang (Viet Nam); Tran, Trung Hieu [School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 712-749 (Korea, Republic of); Shim, Jae-Jin, E-mail: jjshim@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 712-749 (Korea, Republic of)

    2014-11-01

    Conducting poly(o-phenylenediamine) (POPD)/graphene oxide (GO) composites were prepared using a facile and efficient method involving the in-situ polymerization of OPD in the presence of GO in an aqueous medium. Copper sulfate was used as an oxidative initiator for the polymerization of OPD. Scanning electron microscopy and transmission electron microscopy images showed that POPD microfibrils were formed and distributed relatively uniformly with GO sheets in the obtained composites. X-ray diffraction results revealed the highly crystal structure of POPD. This composite exhibited good catalytic activity and stability. These results highlight the potential applications of POPD/GO composites as excellent electrochemical sensors. The composites were used to modify glass carbon electrodes for the chemical detection of hydrogen peroxide in aqueous media. - Highlights: • Graphene oxide/poly(o-phenylenediamine) composites were prepared efficiently. • POPD microfibrils were distributed relatively uniformly with GO sheets. • The composite exhibited good catalytic activity and stability for H{sub 2}O{sub 2} sensing.

  2. Improved properties of chemically modified graphene/poly(methyl methacrylate nanocomposites via a facile in-situ bulk polymerization

    Directory of Open Access Journals (Sweden)

    X. Y. Yuan

    2012-10-01

    Full Text Available The nanosheet of graphene was chemically modified by long alkyl chain for enhanced compatibility with polymer matrix and graphene/poly(methyl methacrylate (PMMA nanocomposites with homogeneous dispersion of the nanosheets and enhanced nanofiller-matrix interfacial interaction were fabricated via a facile in-situ bulk polymerization. The nanocomposites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy and thermogravimetry. The results showed that the graphene nanosheets were fully exfoliated in PMMA matrix and the thermal and mechanical properties of the nanocomposites were significantly improved at low graphene loadings. Large shifts of 15°C in the glass transition temperature and 27°C improvement of onset thermal degradation temperature were achieved with graphene loading as low as 0.07 wt%. A 67% increase in tensile strength was also observed by the addition of only 0.5 wt% graphene. The method used in this study provided a novel route to other graphene-based polymers.

  3. Eletrodos quimicamente modificados aplicados à eletroanálise: uma breve abordagem Chemically modified electrodes applyes to electroanalysis: a brief presentation

    Directory of Open Access Journals (Sweden)

    Maria de Fátima Brito Souza

    1997-04-01

    Full Text Available Chemically modified electrodes (CMEs have been subject of considerable attention since its inception about 23 years ago. CMEs result of a deliberate immobilization of a modifier agent onto the electrode surface obtained through chemical reactions, chemisorption, composite formation or polymer coating. This immobilization seeks transfer the physicochemical properties of the modifier to the electrode surface and thus to dictate and control the behavior of the electrode/solution interface. In recent years the interest in CMEs has increased particularly to enhance the sensitivity and/or the selectivity of electroanalytical techniques. In general higher sensitivity and/or selectivity may be achieved by exploiting one or more of the following phenomena: electrocatalysis, preconcentration and interferents exclusion. This paper deals with the application of CMEs in electroanalysis, including a brief presentation of the more general procedures that have been employed for the modification of electrode surfaces.

  4. Influence of the nycthemeral cycle on the roosting behaviour of the Orange-winged Amazon

    OpenAIRE

    Leiliany N. de Moura; Maria Luisa da Silva; Jacques M. E. Vielliard

    2012-01-01

    Environmental stimuli exert important effects on the expression of the endogenous rhythms. Daily movements of groups of parrots in response to the light/dark cycle have been studied by several researchers. However, the factors modifying the intrinsic rhythmicity of this behaviour remain little known. This study describes how the nychthemeral/circadian periodicity of roost daily movements of the Orange-winged Amazon Amazona amazonica is modified by weather factors. Numbers of parrots arriving ...

  5. Determinação dos hidrocarbonetos saturados e policíclicos aromáticos presentes no material particulado da atmosfera amazônica Chemical composition of aerosol collected in the amazon forest

    Directory of Open Access Journals (Sweden)

    Pérola de Castro Vasconcellos

    1998-07-01

    Full Text Available It was identified and quantified several organic compounds in the atmosphere of a site into Amazon Basin with high impact of biomass burning emission. It was important to know the particulate matter composition with respect to n-alkanes and PAH associated with the particulate matter because they provided indication on the main sources contributing to airborne particles, the contribution of natural vs. man-made emission and the aging of the particles. The main classes of compounds observed were n-alkanes, PAH and nitro-PAH. It was observed the formation of nitro-PAH from photochemical reactions. The aerosol mass concentration is mainly associated with fluoranthene, pyrene and benzo(ghiperylene. Environmental and direct emissions samples (flaming and smoldering were collected and analysed.

  6. Rethinking the strategy of Amazon.com

    NARCIS (Netherlands)

    Heng, Michael S.H.

    2001-01-01

    The strategic challenge facing Amazon.com is that it is not able to convincethe investment community that it is able to generate profits in the long run. The doubtof investors is well grounded. This paper argues that Amazon should make a strategicshift to operate as a provider of technical services

  7. Confluence of the Amazon and Topajos Rivers, Brazil, South America

    Science.gov (United States)

    1991-01-01

    This view shows the confluence of the Amazon and the Topajos Rivers at Santarem, Brazil (2.0S, 55.0W). The Am,azon flows from lower left to upper right of the photo. Below the river juncture of the Amazon and Tapajos, there is considerable deforestation activity along the Trans-Amazon Highway.

  8. Investigation of chemical modifiers for sulfur determination in diesel fuel samples by high-resolution continuum source graphite furnace molecular absorption spectrometry using direct analysis

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Charles S. [Instituto Federal Sul-rio-grandense, Câmpus Pelotas, Pelotas, RS (Brazil); Universidade Federal do Rio Grande do Sul, Instituto de Química, Porto Alegre, RS (Brazil); Vale, Maria Goreti R. [Universidade Federal do Rio Grande do Sul, Instituto de Química, Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Welz, Bernhard [Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Universidade Federal de Santa Catarina, Departamento de Química, Florianópolis, SC (Brazil); Andrade, Jailson B. [Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Dessuy, Morgana B., E-mail: mbdessuy@ufrgs.br [Universidade Federal do Rio Grande do Sul, Instituto de Química, Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil)

    2015-06-01

    High-resolution continuum source graphite furnace molecular absorption spectrometry has been applied for sulfur determination in diesel fuel. The sharp rotational lines of the carbon monosulfide molecule (formed during the vaporization step) were used to measure the absorbance. The analytical line at 258.056 nm was monitored using the sum of three pixels. Different chemical modifiers were investigated and the mixture of palladium and magnesium was used as chemical modifier in combination with iridium as permanent modifier. L-Cysteine was chosen as sulfur standard and the calibration was done against aqueous standard solutions. The proposed method was applied for the analyses of four diesel samples: two S10 samples and two S500 samples. The trueness of the method was checked with a certified reference material (CRM) of sulfur in diesel fuel (NIST 2724b). Accurate results, for samples and CRM, were achieved after a dilution with propan-1-ol. The following figures of merit were obtained: characteristic mass of 17 ± 3 ng, limit of detection and limit of quantification of 1.4 mg kg{sup −1} and 4.7 mg kg{sup −1}, respectively. - Highlights: • Ir, Ru and Zr were investigated as permanent modifiers. • Ca, Mg, Pd and Pd/Mg were investigated as modifiers in solution. • Indirect determination of sulfur monitoring the molecular absorbance of the CS • Direct analysis of diesel samples using a dilution in propan-1-ol.

  9. A Standardized Chemically Modified Curcuma longa Extract Modulates IRAK-MAPK Signaling in Inflammation and Potentiates Cytotoxicity.

    Science.gov (United States)

    Rana, Minakshi; Maurya, Preeti; Reddy, Sukka S; Singh, Vishal; Ahmad, Hafsa; Dwivedi, Anil K; Dikshit, Madhu; Barthwal, Manoj K

    2016-01-01

    The TLR/IL-1R pathway is a critical signaling module that is misregulated in pathologies like inflammation and cancer. Extracts from turmeric (Curcuma longa L.) enriched in curcumin and carbonyls like turmerones have been shown to exert potent anti-inflammatory effects. The present study evaluated the anti-inflammatory activity, cytotoxic effect and the underlying mechanism of a novel chemically modified, non-carbonyl compound enriched Curcuma longa L. (C. longa) extract (CMCE). CMCE (1 or 10 μg/mL; 14 h) significantly decreased LPS (50-100 ng/mL) induced TNF-α and IL-1β production in THP-1 cells, human, and mouse whole blood as measured by ELISA. LPS-induced IRAK1, MAPK activation, TLR4 expression, TLR4-MyD88 interaction, and IκBα degradation were significantly reduced in CMCE pre-treated THP-1 cells as assessed by Western blotting. CMCE (30, 100, and 300 mg/kg; 10 days p.o.) pre-treated and LPS (10 mg/kg) challenged Swiss mice exhibited attenuated plasma TNF-α, IL-1β, nitrite, aortic iNOS expression, and vascular dysfunction. In a PI permeability assay, cell lines derived from acute myeloid leukemia were most sensitive to the cytotoxic effects of CMCE. Analysis of Sub-G1 phase, Annexin V-PI positivity, loss of mitochondrial membrane potential, increased caspase-3, and PARP-1 activation confirmed CMCE induced apoptosis in HL-60 cells. IRAK inhibition also sensitized HL-60 cells to CMCE induced cytotoxicity. The present study defines the mechanism underlying the action of CMCE and suggests a therapeutic potential for its use in sepsis and leukemia.

  10. A Standardized Chemically Modified Curcuma longa Extract Modulates IRAK-MAPK Signaling in Inflammation and Potentiates Cytotoxicity

    Directory of Open Access Journals (Sweden)

    Minakshi Rana

    2016-07-01

    Full Text Available The TLR/IL-1R pathway is a critical signaling module that is misregulated in pathologies like inflammation and cancer. Extracts from turmeric (Curcuma longa L. enriched in curcumin and carbonyls like turmerones have been shown to exert potent anti-inflammatory effects. The present study evaluated the anti-inflammatory activity, cytotoxic effect and the underlying mechanism of a novel chemically modified, non-carbonyl compound enriched Curcuma longa L. (C. longa extract (CMCE. CMCE (1 or 10 µg/mL; 14 h significantly decreased LPS (50-100 ng/mL induced TNF-α and IL-1β production in THP-1 cells, human, and mouse whole blood as measured by ELISA. LPS-induced IRAK1, MAPK activation, TLR4 expression, TLR4-MyD88 interaction and IκBα degradation were significantly reduced in CMCE pre-treated THP-1 cells as assessed by Western blotting. CMCE (30, 100 and 300 mg/kg; 10 days p.o. pre-treated and LPS (10 mg/kg challenged Swiss mice exhibited attenuated plasma TNF-α, IL-1β, nitrite, aortic iNOS expression and vascular dysfunction. In a PI permeability assay, cell lines derived from acute myeloid leukemia were most sensitive to the cytotoxic effects of CMCE. Analysis of Sub-G1 phase, Annexin V-PI positivity, loss of mitochondrial membrane potential, increased caspase-3 and PARP-1 activation confirmed CMCE induced apoptosis in HL-60 cells. IRAK inhibition also sensitized HL-60 cells to CMCE induced cytotoxicity. The present study defines the mechanism underlying the action of CMCE and suggests a therapeutic potential for its use in sepsis and leukemia.

  11. A Standardized Chemically Modified Curcuma longa Extract Modulates IRAK-MAPK Signaling in Inflammation and Potentiates Cytotoxicity.

    Science.gov (United States)

    Rana, Minakshi; Maurya, Preeti; Reddy, Sukka S; Singh, Vishal; Ahmad, Hafsa; Dwivedi, Anil K; Dikshit, Madhu; Barthwal, Manoj K

    2016-01-01

    The TLR/IL-1R pathway is a critical signaling module that is misregulated in pathologies like inflammation and cancer. Extracts from turmeric (Curcuma longa L.) enriched in curcumin and carbonyls like turmerones have been shown to exert potent anti-inflammatory effects. The present study evaluated the anti-inflammatory activity, cytotoxic effect and the underlying mechanism of a novel chemically modified, non-carbonyl compound enriched Curcuma longa L. (C. longa) extract (CMCE). CMCE (1 or 10 μg/mL; 14 h) significantly decreased LPS (50-100 ng/mL) induced TNF-α and IL-1β production in THP-1 cells, human, and mouse whole blood as measured by ELISA. LPS-induced IRAK1, MAPK activation, TLR4 expression, TLR4-MyD88 interaction, and IκBα degradation were significantly reduced in CMCE pre-treated THP-1 cells as assessed by Western blotting. CMCE (30, 100, and 300 mg/kg; 10 days p.o.) pre-treated and LPS (10 mg/kg) challenged Swiss mice exhibited attenuated plasma TNF-α, IL-1β, nitrite, aortic iNOS expression, and vascular dysfunction. In a PI permeability assay, cell lines derived from acute myeloid leukemia were most sensitive to the cytotoxic effects of CMCE. Analysis of Sub-G1 phase, Annexin V-PI positivity, loss of mitochondrial membrane potential, increased caspase-3, and PARP-1 activation confirmed CMCE induced apoptosis in HL-60 cells. IRAK inhibition also sensitized HL-60 cells to CMCE induced cytotoxicity. The present study defines the mechanism underlying the action of CMCE and suggests a therapeutic potential for its use in sepsis and leukemia. PMID:27504095

  12. Biosorption of cesium by native and chemically modified biomass of marine algae: introduce the new biosorbents for biotechnology applications

    Energy Technology Data Exchange (ETDEWEB)

    Jalali-Rad, R. [Department of Biotechnology, Nuclear Research Center, Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of)]. E-mail: rjalali@aeoi.org.ir; Ghafourian, H. [Department of Biotechnology, Nuclear Research Center, Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of); Asef, Y. [Department of Biotechnology, Nuclear Research Center, Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of); Dalir, S.T. [Department of Biotechnology, Nuclear Research Center, Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of); Sahafipour, M.H. [Department of Biotechnology, Nuclear Research Center, Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of); Gharanjik, B.M. [Offshore Fisheries Research Center, Chabahar (Iran, Islamic Republic of)

    2004-12-10

    Biosorption batch experiments were conducted to determine the cesium binding ability of native biomass and chemically modified biosorbents derived from marine algae, namely ferrocyanide algal sorbents type 1 and type 2 (FASs1 and FASs2). The applicability of the Langmuir and Freundlich isotherms for representation of the experimental data was investigated. The cesium sorption performances of the various types of sorbents were compared using the maximum capacities (q{sub max} values) obtained from fitting the Langmuir isotherm to the values calculated from the sorption experiments, which FASs type 1 and type 2 showed better sorption performances for cesium. FASs1 and FASs2 derived from formaldehyde and glutaraldehyde crosslinked Padina australis exhibited lower sorption capacities than those prepared from the non-crosslinked one. Most of the cesium ions were bound to FASs1, derived from Sargassum glaucescens and P. australis, in <2 min and equilibrium reached within the first 30 min of contact. Biosorption of cesium by FASs1 derived from P. australis and Cystoseria indica was constantly occurred at a wide range of pH, between 1 and 10, and the highest removal took place at pH 4. The presence of sodium and potassium at 0.5 and 1 mM did not inhibit cesium biosorption by algae biomass. The maximum cesium uptake was acquired using the large particles of FAS2 originated from S. glaucescens (2-4 mm). Desorption of cesium from the metal-laden FASs1 (from P. australis, S. glaucescens and Dictyota indica) was completely achieved applying 0.5 and 1 M NaOH and KOH, although the cesium sorption capacity of the biosorbents (from C. indica and S. glaucescens) decreased by 46-51% after 9 sorption-desorption cycles.

  13. Getting started With Amazon Redshift

    CERN Document Server

    Bauer, Stefan

    2013-01-01

    Getting Started With Amazon Redshift is a step-by-step, practical guide to the world of Redshift. Learn to load, manage, and query data on Redshift.This book is for CIOs, enterprise architects, developers, and anyone else who needs to get familiar with RedShift. The CIO will gain an understanding of what their technical staff is working on; the technical implementation personnel will get an in-depth view of the technology, and what it will take to implement their own solutions.

  14. Equity valuation : Amazon.com

    OpenAIRE

    Carvalho, Pedro José Simões

    2014-01-01

    This dissertation is performed towards the final goal of achieving a value for Amazon.com. For this, all the relevant methods were explored and described, in order to check/choose which ones were the most appropriate. For this evaluation it was chosen the APV method and multiple valuations. After the valuation a VAR analysis was performed and a comparison with the reports released from investment banks was done. The target price achieved was 376.78 euros giving a BUY/ HOLD r...

  15. Amazon SimpleDB LITE

    CERN Document Server

    Chaganti, Prabhakar

    2011-01-01

    This focused book is an extracted LITE version of Packt's full: Amazon SimpleDB Developer Guide. It concentrates on getting a grounding in the value of SimpleDB, and shows how to set up an AWS account, enable a SimpleDB service for the account, and install and set up libraries for Java, PHP, and Python. If you are a developer wanting to get to grips with a primer into SimpleDB, then this book is for you. You do not need to know anything about SimpleDB to read and learn from this book, and no basic knowledge is strictly necessary.

  16. Activation of the ERK1/2 Signaling Pathway during the Osteogenic Differentiation of Mesenchymal Stem Cells Cultured on Substrates Modified with Various Chemical Groups

    Directory of Open Access Journals (Sweden)

    Bing Bai

    2013-01-01

    Full Text Available The current study examined the influence of culture substrates modified with the functional groups –OH, –COOH, –NH2, and –CH3 using SAMs technology, in conjunction with TAAB control, on the osteogenic differentiation of rabbit BMSCs. The CCK-8 assay revealed that BMSCs exhibited substrate-dependent cell viability. The cells plated on –NH2- and –OH-modified substrates were well spread and homogeneous, but those on the –COOH- and –CH3-modified substrates showed more rounded phenotype. The mRNA expression of BMSCs revealed that –NH2-modified substrate promoted the mRNA expression and osteogenic differentiation of the BMSCs. The contribution of ERK1/2 signaling pathway to the osteogenic differentiation of BMSCs cultured on the –NH2-modified substrate was investigated in vitro. The –NH2-modified substrate promoted the expression of integrins; the activation of FAK and ERK1/2. Inhibition of ERK1/2 activation by PD98059, a specific inhibitor of the ERK signaling pathway, blocked ERK1/2 activation in a dose-dependent manner, as revealed for expression of Cbfα-1 and ALP. Blockade of ERK1/2 phosphorylation in BMSCs by PD98059 suppressed osteogenic differentiation on chemical surfaces. These findings indicate a potential role for ERK in the osteogenic differentiation of BMSCs on surfaces modified by specific chemical functional groups, indicating that the microenvironment affects the differentiation of BMSCs. This observation has important implications for bone tissue engineering.

  17. How many more dams in the Amazon?

    International Nuclear Information System (INIS)

    The Amazon watershed harbors a megadiversity of terrestrial and aquatic plants and animals. Mechanisms that sustain this biodiversity are the water level fluctuations the fluvial dynamics and the intense gene flux due to permanent integration of climatological, geomorphological and biological components of the system. The construction of hydroelectric reservoirs to support economic development of Brazil and other countries that share the Amazon basin will interfere with the ecological dynamics of this ecosystem changing the hydrological, hydrosocial and fundamental processes. Furthermore the construction of Andean reservoirs can disrupt the connectivity with the lower Amazon ecosystem. Principles of ecohydrologies, ecological engineering and preservation of key river basins, have to be applied in order to optimize energy production and promote conservation practices. Long term planning and integration of countries that share the Amazon basin is a strategic decision to control and develop the hydropower exploitation in the region. - Highlights: • The Amazon basin is an ecosystem of megadiversity. • The demand for energy threatens this ecosystem. • Climate, water, forests and floodplain interacts in the Amazon basin. • Dams in the Amazon basin will impact the hydrological and biological systems. • Ecohydrological principles and ecological engineering technology are necessary

  18. Preparation and use of chemically modified MCM-41 and silica gel as selective adsorbents for Hg(II) ions

    International Nuclear Information System (INIS)

    Adsorbents for Hg(II) ion extraction were prepared using amorphous silica gel and ordered MCM-41. Grafting with 2-(3-(2-aminoethylthio)propylthio)ethanamine was used to functionalize the silica. The functionalized adsorbents were characterized by nitrogen adsorption, X-ray diffraction, 13C MAS NMR spectroscopy and thermogravimetric analysis. The adsorption properties of the modified silica gel and MCM-41 were compared using batch method. The effect of pH, stirring time, ionic strength and foreign ions were studied. The extraction of Hg(II) ions occurred rapidly with the modified MCM-41 and the optimal pH range for the extraction by the modified materials was pH 4-7. Foreign ions, especially Cl- had some effect on the extraction efficiency of the modified silica gel and the modified MCM-41. The adsorption behavior of both adsorbents could be described by a Langmuir model at 298 K, and the maximum adsorption capacity of the modified silica gel and MCM-41 at pH 3 was 0.79 and 0.70 mmol g-1, respectively. The modified MCM-41 showed a larger Langmuir constant than that of the modified silica gel, indicating a better ability for Hg(II) ion adsorption. The results indicate that the structure of the materials affects the adsorption behavior. These materials show a potential for the application as effective and selective adsorbents for Hg(II) removal from water

  19. Carbon Tetrachloride Emissions from the Amazon Forest

    Science.gov (United States)

    Jardine, K.; Chambers, J. Q.; Higuchi, N.; Jardine, A. B.; Martin, S. T.; Manzi, A. O.

    2014-12-01

    As a chemically inert greenhouse gas in the troposphere with lifetimes up to 50 years but active in ozone destruction in the stratosphere, carbon tetrachloride (CCl4) plays a major role in the atmospheric chlorine budget and is widely considered strictly of anthropogenic origin deriving from numerous industrial processes and products. However, satellite remote sensing studies have shown higher concentrations at the Equator, and earlier work has suggested possible biogenic sources. Here we present highly vertically-resolved atmospheric gradients of CCl4 within and above a primary rainforest ecosystem from three towers in the Central Amazon. The observed buildup of CCl4 mixing ratios near the top of the main canopies provides new evidence for a potentially large biogenic source from the Basin. By demonstrating the need to represent tropical forests as biogenic sources of CCl4, our study may help narrow the gap between remote sensing observations of CCl4 and emission, chemistry, and transport models and therefore lead to improved predictions of its role in atmospheric chemistry and climate.

  20. Review of long-term adverse effects associated with the use of chemically-modified animal and nonanimal source hyaluronic acid dermal fillers

    OpenAIRE

    Edwards, Paul

    2008-01-01

    Paul C Edwards1, John E Fantasia21Associate Professor (Clinical), Department of Periodontics and Oral Medicine, Pathology and Oncology, University of Michigan School of Dentistry, Ann Arbor MI, USA; 2Chief, Division of Oral Pathology, Department of Dental Medicine, Long Island Jewish Medical Center, New Hyde Park, NY, USAAbstract: Although only recently introduced, chemically-modified hyaluronic acid dermal fillers have gained widespread acceptance as “redefining” dermal f...

  1. Review of long-term adverse effects associated with the use of chemically-modified animal and nonanimal source hyaluronic acid dermal fillers

    OpenAIRE

    Edwards, Paul C.; John E Fantasia

    2007-01-01

    Paul C Edwards1, John E Fantasia21Associate Professor (Clinical), Department of Periodontics and Oral Medicine, Pathology and Oncology, University of Michigan School of Dentistry, Ann Arbor MI, USA; 2Chief, Division of Oral Pathology, Department of Dental Medicine, Long Island Jewish Medical Center, New Hyde Park, NY, USAAbstract: Although only recently introduced, chemically-modified hyaluronic acid dermal fillers have gained widespread acceptance as “redefining” dermal f...

  2. Preparation, Biodegradation of Coconut Oil Driven Chemically Modified Bovine Serum Albumin Microparticles of Encapsulated Cicer arietinum Amylase and Study of Their Application in Washing Detergents

    OpenAIRE

    Kirti Rani; Vartika Mehta

    2014-01-01

    In present work, Cicer arietinum amylase was encapsulated by emulsification through covalent coupling by glutaraldehyde into chemically modified bovine serum albumin. Biodegradation of coconut oil driven emulsified bovine serum albumin encapsulated Cicer arietinum amylase was carried out by the alkaline protease for its controlled and sustained release of encapsulated enzyme from prepared microparticles of encapsulated Cicer arietinum amylase and its stability increased up to 6 months as comp...

  3. Preparation, Biodegradation of Coconut Oil Driven Chemically Modified Bovine Serum Albumin Microparticles of Encapsulated Cicer arietinum Amylase and Study of Their Application in Washing Detergents

    Directory of Open Access Journals (Sweden)

    Kirti Rani

    2014-10-01

    Full Text Available In present work, Cicer arietinum amylase was encapsulated by emulsification through covalent coupling by glutaraldehyde into chemically modified bovine serum albumin. Biodegradation of coconut oil driven emulsified bovine serum albumin encapsulated Cicer arietinum amylase was carried out by the alkaline protease for its controlled and sustained release of encapsulated enzyme from prepared microparticles of encapsulated Cicer arietinum amylase and its stability increased up to 6 months as compared to free enzyme. Its biodegradation was carried out by the using different concentration of alkaline protease (5U, 10U, 15U, 20U, 25U, 30U, 35U, 40U. Further, this coconut oil driven chemically modified bovine serum albumin microparticles of encapsulated Cicer arietinum amylase with alkaline protease were used with detergents for washing of stained cloths which have rust, gel pen ink, grease and chocolate strains. These chosen strains are very commonly present on uniforms of school going children which are very tough upon drying, hence, not to be easily vanish with well known brand detergents upon in one wash. But, the mixture solution of coconut oil driven chemically modified bovine serum albumin microparticles of encapsulated Cicer arietinum amylase along with alkaline protease were used with detergents powder for washing of these dry tough strains (rust, gel pen ink, grease and chocolate strains leads to vanishing these strains very fast with absolute clear results were found as compared to results of washing of stained cloths with detergents only.

  4. Biomarkers of Mercury Exposure in the Amazon

    OpenAIRE

    Nathália Santos Serrão de Castro; Marcelo de Oliveira Lima

    2014-01-01

    Mercury exposure in the Amazon has been studied since the 1980s decade and the assessment of human mercury exposure in the Amazon is difficult given that the natural occurrence of this metal is high and the concentration of mercury in biological samples of this population exceeds the standardized value of normality established by WHO. Few studies have focused on the discovery of mercury biomarkers in the region's population. In this way, some studies have used genetics as well as immunologica...

  5. Modeling Amazon Deforestation for Policy Purposes

    OpenAIRE

    Granger, Clive W.J.; Lykke E. Andersen

    2006-01-01

    Brazil has long ago removed most of the perverse government incentives that stimulated massive deforestation in the Amazon in the 70s and 80s, but one highly controversial policy remains: Road building. While data is now abundantly available due to the constant satellite surveillance of the Amazon, the analytical methods typically used to analyze the impact of roads on natural vegetation cover are methodologically weak and not very helpful to guide public policy. This paper discusses the resp...

  6. Archaeometric study of Amazon ceramic

    International Nuclear Information System (INIS)

    There is no evidence of urban civilization in Brazilian prehistory; most inhabitants lived in tribal organization, probably with regional economic integration among several independent tribes. There are few evidences of seasonal migrations between the coast and the inland of southern Brazil. Some specialized horticulturists competed among themselves but other groups lived more isolatedly and probably peacefully, in the upper interfluvial regions. The chiefdom system is supposed to have existed only along the Amazon River. In this region, some pottery makers may have been specialized craftsmen and finest ceramics, that should have been exported from one village/region to another, can be found. In this study we tested some limited possibilities in three different cultural and regional contexts to see if application of analytic analysis in economically and politically 'simple' societies should give any results. (author)

  7. Bold enterprise in Amazon basin

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, D.

    1980-08-30

    The aim of the Jari project in Brazil is to produce food and forest products for world markets by developing a 15,000 square km tract in the Amazon basin. A pumpmill and power plant came on stream in 1979 and since then have been meeting production targets of high quality bleached pulp. The key to the success of the project has been the introduction of a fast-growing hardwood native to S.E. Asia- Gmelina arborea which reaches a height of 30 m after 10 years, and is suitable for most wood products: pulp, sawn timber, veneer, plywood and particleboard. It is stated that preparations are under-way to introduce Jari hardwood to European markets.

  8. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  9. Green Ocean Amazon 2014/15 Terrestrial Ecosystem Project (Geco) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Jardine, Kolby [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-06-01

    In conjunction with the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility GoAmazon campaign, the Terrestrial Ecosystem Science (TES)-funded Green Ocean Amazon (GoAmazon 2014/15) terrestrial ecosystem project (Geco) was designed to: • evaluate the strengths and weaknesses of leaf-level algorithms for biogenic volatile organic compounds (BVOCs) emissions in Amazon forests near Manaus, Brazil, and • conduct mechanistic field studies to characterize biochemical and physiological processes governing leaf- and landscape-scale tropical forest BVOC emissions, and the influence of environmental drivers that are expected to change with a warming climate. Through a close interaction between modeling and observational activities, including the training of MS and PhD graduate students, post-doctoral students, and technicians at the National Institute for Amazon Research (INPA), the study aimed at improving the representation of BVOC-mediated biosphere-atmosphere interactions and feedbacks under a warming climate. BVOCs can form cloud condensation nuclei (CCN) that influence precipitation dynamics and modify the quality of down welling radiation for photosynthesis. However, our ability to represent these coupled biosphere-atmosphere processes in Earth system models suffers from poor understanding of the functions, identities, quantities, and seasonal patterns of BVOC emissions from tropical forests as well as their biological and environmental controls. The Model of Emissions of Gases and Aerosols from Nature (MEGAN), the current BVOC sub-model of the Community Earth System Model (CESM), was evaluated to explore mechanistic controls over BVOC emissions. Based on that analysis, a combination of observations and experiments were studied in forests near Manaus, Brazil, to test existing parameterizations and algorithm structures in MEGAN. The model was actively modified as needed to improve tropical BVOC emission simulations on

  10. Enzymatically hydrolysed, acetylated and dually modified corn starch: physico-chemical, rheological and nutritional properties and effects on cake quality.

    Science.gov (United States)

    Sahnoun, Mouna; Ismail, Nouha; Kammoun, Radhouane

    2016-01-01

    Corn starch was treated by enzymatic hydrolysis with Aspergillus oryzae S2 α-amylase, acetylation with vinyl acetate, and dual modification. The dual modified starch displayed a higher substitution degree than the acetylated starch and lower reducing sugar content than the hydrolysed starch. The results revealed that the cooling viscosity and amylose content of those products decrease (P cake formulations at 5 and 10 % concentrations on a wheat flour basis and compared to native starch. The results revealed that when applied at 5 % concentrations, the modified starches reduced the hardness, cohesion, adhesion and chewiness of baked cakes and enhanced their elasticity, volume, height, crust color, and appearance as compared to native starch. These effects were more pronounced for the cake incorporating the dually modified starch.

  11. The Amazon Tall Tower Observatory (ATTO in the remote Amazon Basin: overview of first results from ecosystem ecology, meteorology, trace gas, and aerosol measurements

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2015-04-01

    Full Text Available The Amazon Basin plays key roles in the carbon and water cycles, climate change, atmospheric chemistry, and biodiversity. It already has been changed significantly by human activities, and more pervasive change is expected to occur in the next decades. It is therefore essential to establish long-term measurement sites that provide a baseline record of present-day climatic, biogeochemical, and atmospheric conditions and that will be operated over coming decades to monitor change in the Amazon region as human perturbations increase in the future. The Amazon Tall Tower Observatory (ATTO has been set up in a pristine rain forest region in the central Amazon Basin, about 150 km northeast of the city of Manaus. An ecological survey including a biodiversity assessment has been conducted in the forest region surrounding the site. Two 80 m towers have been operated at the site since 2012, and a 325 m tower is nearing completion in mid-2015. Measurements of micrometeorological and atmospheric chemical variables were initiated in 2012, and their range has continued to broaden over the last few years. The meteorological and micrometeorological measurements include temperature and wind profiles, precipitation, water and energy fluxes, turbulence components, soil temperature profiles and soil heat fluxes, radiation fluxes, and visibility. A tree has been instrumented to measure stem profiles of temperature, light intensity, and water content in cryptogamic covers. The trace gas measurements comprise continuous monitoring of carbon dioxide, carbon monoxide, methane, and ozone at 5 to 8 different heights, complemented by a variety of additional species measured during intensive campaigns (e.g., VOC, NO, NO2, and OH reactivity. Aerosol optical, microphysical, and chemical measurements are made above the canopy as well as in the canopy space. They include light scattering and absorption, aerosol fluorescence, number and volume size distributions, chemical

  12. [Effects of Different Modifier Concentrations on Lead-Zinc Tolerance, Subcellular Distribution and Chemical Forms for Four Kinds of Woody Plants].

    Science.gov (United States)

    Chen, Yong-hua; Zhang, Fu-yun; Wu, Xiao-fu; Liang, Xi; Yuan, Si-wen

    2015-10-01

    Four kinds of lead-zinc tolerant woody plants: Nerium oleander, Koelreuteria paniculata, Paulownia and Boehmeria were used as materials to estimate their enrichment and transferable capacity of lead (Pb) and zinc (Zn) and analyze the subcellular distribution and chemical speciation of Zn and Ph in different parts of plants, under different modifier concentrations (CK group: 100% lead-zinc slag plus a small amount of phosphate fertilizer, improved one: 85% of lead-zinc slag ± 10% peat ± 5% bacterial manure plus a small amount of phosphate fertilizer, improved two: 75% lead-zinc slag ± 20% peat ± 5% bacterial manure ± a small amount of phosphate). Results showed that: (1) The content of Pb, Zn in matrix after planting four kinds of plants was lower than before, no significant difference between improved one and improved two of Nerium oleander and Boehmeria was found, but improved two was better than improved one of Paulownia, while improved one was better than improved two of Koelreuteria paniculata; Four plants had relatively low aboveground enrichment coefficient of Pb and Zn, but had a high transfer coefficient, showed that the appropriate modifier concentration was able to improve the Pb and Zn enrichment and transfer ability of plants. (2) In subcellular distribution, most of Pb and Zn were distributed in plant cell wall components and soluble components while the distribution in cell organelles such as mitochondria, chloroplasts and nucleus component were less. Compared with CK group, two improved group made soluble components of the cell walls of Pb fixation and retention of zinc role in the enhancement. (3) As for the chemical forms of Pb and Zn in plants, the main chemical forms of Pb were hydrochloric acid, sodium chloride and ethanol extractable forms, while other chemical form contents were few, the main chemical forms of Zn were different based on plant type. Compared with CK group, the proportion of the active Pb chemical form in different plant

  13. Chemically modified polymeric resins for separation of cations, organic acids, and small polar moleculea by high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J.B.

    1993-07-01

    This thesis is divided into 4 parts: a review, ion chromatography of metal cations on carboxylic resins, separation of hydrophilic organic acids and small polar compounds on macroporous resin columns, and use of eluent modifiers for liquid chromatographic separation of carboxylic acids using conductivity detection.

  14. Enzymatically hydrolysed, acetylated and dually modified corn starch: physico-chemical, rheological and nutritional properties and effects on cake quality.

    Science.gov (United States)

    Sahnoun, Mouna; Ismail, Nouha; Kammoun, Radhouane

    2016-01-01

    Corn starch was treated by enzymatic hydrolysis with Aspergillus oryzae S2 α-amylase, acetylation with vinyl acetate, and dual modification. The dual modified starch displayed a higher substitution degree than the acetylated starch and lower reducing sugar content than the hydrolysed starch. The results revealed that the cooling viscosity and amylose content of those products decrease (P oil absorption capacity was observed for the acetylated starch and, which was less pronounced for the enzymatically hydrolysed starch but more pronounced for the enzymatically hydrolysed acetylated product. The latter product underwent an increase in resistant starch content, which is induced by a rise in hydrolysis time to attain about 67 % after 1 h of reaction. The modified starch samples were added to cake formulations at 5 and 10 % concentrations on a wheat flour basis and compared to native starch. The results revealed that when applied at 5 % concentrations, the modified starches reduced the hardness, cohesion, adhesion and chewiness of baked cakes and enhanced their elasticity, volume, height, crust color, and appearance as compared to native starch. These effects were more pronounced for the cake incorporating the dually modified starch. PMID:26787967

  15. Rheological and chemical evaluation on the ageing properties of SBS polymer modified bitumen: From the laboratory to the field

    NARCIS (Netherlands)

    Liu, G.; Nielsen, E.; Komacka, J.; Greet, L.; Ven, M.V.D.

    2014-01-01

    This study investigated the ageing properties of the styrene-butadiene- styrene polymer modified bitumen (SBS PMB) from the laboratory to the field. The virgin SBS PMB had been kept for 23 years and its field-aged binder was extracted from the reclaimed stone matrix asphalt (SMA) after the 22-year s

  16. Iron cycling in the Amazon River Basin: the isotopic perspective

    Science.gov (United States)

    Poitrasson, Franck; Vieira, Lucieth; Mulholland, Daniel; Seyler, Patrick; Sondag, Francis; Allard, Thierry

    2014-05-01

    With the global climate change and increasing anthropic pressure on nature, it is important to find new indicators of the response of complex systems like the Amazon River Basin. In particular, new tracers like iron isotopes may tell us much on processes such as the chemical exchanges between rivers, soils and the biosphere. Pioneering studies revealed that for some river waters, large δ57Fe fractionations are observed between the suspended and dissolved load (Bergquist and Boyle, 2006), and isotopic variations were also recognized on the suspended matter along the hydrological cycle (Ingri et al., 2006). On land, soil studies from various locations have shown that δ57Fe signatures depend mostly on the weathering regime (Fantle and DePaolo, 2004; Emmanuel et al., 2005; Wiederhold et al., 2007; Poitrasson et al., 2008). It thus seems that Fe isotopes could become an interesting new tracer of the exchanges between soils, rivers and the biosphere. We therefore conducted Fe isotope surveys through multidisciplinary field missions on rivers from the Amazon Basin. It was confirmed that acidic, organic-rich black waters show strong Fe isotope fractionation between particulate and dissolved loads. Furthermore, this isotopic fractionation varies along the hydrological cycle, like previously uncovered in boreal waters suspended matter. In contrast, unfiltered waters show very little variation with time. It was also found that Fe isotopes remain a conservative tracer even in the case of massive iron loss during the mixing of chemically contrasted waters such as the Negro and Solimões tributaries of the Amazon River. Given that >95% of the Fe from the Amazon River is carried as detrital materials, our results lead to the conclusion that the Fe isotope signature delivered to the Atlantic Ocean is undistinguishable from the continental crust value, in contrast to previous inferences. The results indicate that Fe isotopes in rivers represent a promising indicator of the

  17. Modelling sustainable international tourism demand to the Brazilian Amazon

    NARCIS (Netherlands)

    J.A. Divino (Jose Angelo); M.J. McAleer (Michael)

    2008-01-01

    textabstractThe Amazon rainforest is one of the world’s greatest natural wonders and holds great importance and significance for the world’s environmental balance. Around 60% of the Amazon rainforest is located in the Brazilian territory. The two biggest states of the Amazon region are Amazonas (the

  18. Business as Usual: Amazon.com and the Academic Library

    Science.gov (United States)

    Van Ullen, Mary K.; Germain, Carol Anne

    2002-01-01

    In 1999, Steve Coffman proposed that libraries form a single interlibrary loan based entity patterned after Amazon.com. This study examined the suitability of Amazon.com's Web interface and record enhancements for academic libraries. Amazon.com could not deliver circulating monographs in the University at Albany Libraries' collection quickly…

  19. Electron transfer modifies chemical properties of C70 fullerene surface: an ab initio molecular dynamics study of C70O3 molozonides doped with light atoms

    OpenAIRE

    Morrison, Carole; Bil, Andrzej; Hutter, Jurg

    2014-01-01

    Light metal atoms such as Li, K (electronic state 2S 1/2) or Ca (1S0) encapsulated in a C 70 cage considerably modifies the chemical properties of the fullerene surface due to metal-to-cage electron transfer. H-doped and anion ozonide systems were also considered to validate the electron transfer hypothesis. The relative stabilities of the eight isomers of the C 70O3 molozonide series at room temperature depend on the identity of the endohedral guest, as was the preferred channel for thermal ...

  20. Modelling conservation in the Amazon basin

    Science.gov (United States)

    Soares-Filho, Britaldo Silveira; Nepstad, Daniel Curtis; Curran, Lisa M.; Cerqueira, Gustavo Coutinho; Garcia, Ricardo Alexandrino; Ramos, Claudia Azevedo; Voll, Eliane; McDonald, Alice; Lefebvre, Paul; Schlesinger, Peter

    2006-03-01

    Expansion of the cattle and soy industries in the Amazon basin has increased deforestation rates and will soon push all-weather highways into the region's core. In the face of this growing pressure, a comprehensive conservation strategy for the Amazon basin should protect its watersheds, the full range of species and ecosystem diversity, and the stability of regional climates. Here we report that protected areas in the Amazon basin-the central feature of prevailing conservation approaches-are an important but insufficient component of this strategy, based on policy-sensitive simulations of future deforestation. By 2050, current trends in agricultural expansion will eliminate a total of 40% of Amazon forests, including at least two-thirds of the forest cover of six major watersheds and 12 ecoregions, releasing 32 +/- 8Pg of carbon to the atmosphere. One-quarter of the 382 mammalian species examined will lose more than 40% of the forest within their Amazon ranges. Although an expanded and enforced network of protected areas could avoid as much as one-third of this projected forest loss, conservation on private lands is also essential. Expanding market pressures for sound land management and prevention of forest clearing on lands unsuitable for agriculture are critical ingredients of a strategy for comprehensive conservation.

  1. Advance in researches on chemically modified starch used in food%变性淀粉在食品中的应用研究进展

    Institute of Scientific and Technical Information of China (English)

    张静静; 梁艳; 宫丽华; 崔波

    2014-01-01

    Starch has become a kind of important industrial raw material as renewable natural resources . Because many inherent qualities of the original starch( infusibility in cold water,instability of paste liquid in acid,heat and shearing action)limit its industrial application.So people developed modified technology according to the starch structure and physical and chemical properties ,named modified starch .With many good properties of the modified starch ,its application in food industry is becoming more and more widely at home and abroad.This paper introduces preparation methods of modified starch,domain,and prospects the development of modified starch.%淀粉作为一种可再生的天然资源,已成为重要的工业原料。由于原淀粉的许多固有性质(冷水不溶性,糊液在酸、热、剪切作用下不稳定)限定了淀粉的工业应用,人们根据淀粉的结构和理化性质开发了淀粉的变性技术,即变性淀粉。随着变性淀粉诸多优良性质的显现,其在国内外食品行业的应用也越来越广泛。本文介绍了变性淀粉的制备方法及应用领域,并对变性淀粉的发展做了展望。

  2. Smoke Invigoration Versus Inhibition of Clouds over the Amazon

    Science.gov (United States)

    Koren, Ilan; Martins, J. Vanderlei; Lorraine, A. Remer; Afargan, Hila

    2008-01-01

    The effect of anthropogenic aerosols on clouds is one of the most important and least understood aspects of human-induced climate change. Small changes in the amount of cloud coverage can produce a climate forcing equivalent in magnitude and opposite in sign to that caused by anthropogenic greenhouse gases, and changes in cloud height can shift the effect of clouds from cooling to warming. Focusing on the Amazon, we show a smooth transition between two opposing effects of aerosols on clouds: the microphysical and the radiative. We show how a feedback between the optical properties of aerosols and the cloud fraction can modify the aerosol forcing, changing the total radiative energy and redistributing it over the atmospheric column.

  3. Cloud Condensation Nuclei Activity of Aerosols during GoAmazon 2014/15 Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Martin, S. T. [Harvard Univ., Cambridge, MA (United States); Kleinman, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Thalman, R. M. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-03-01

    Aerosol indirect effects, which represent the impact of aerosols on climate through influencing the properties of clouds, remain one of the main uncertainties in climate predictions (Stocker et al. 2013). Reducing this large uncertainty requires both improved understanding and representation of aerosol properties and processes in climate models, including the cloud activation properties of aerosols. The Atmospheric System Research (ASR) science program plan of January 2010 states that: “A key requirement for simulating aerosol-cloud interactions is the ability to calculate cloud condensation nuclei and ice nuclei (CCN and IN, respectively) concentrations as a function of supersaturation from the chemical and microphysical properties of the aerosol.” The Observations and Modeling of the Green Ocean Amazon (GoAmazon 2014/15) study seeks to understand how aerosol and cloud life cycles are influenced by pollutant outflow from a tropical megacity (Manaus)—in particular, the differences in cloud-aerosol-precipitation interactions between polluted and pristine conditions. One key question of GoAmazon2014/5 is: “What is the influence of the Manaus pollution plume on the cloud condensation nuclei (CCN) activities of the aerosol particles and the secondary organic material in the particles?” To address this question, we measured size-resolved CCN spectra, a critical measurement for GoAmazon2014/5.

  4. Chemically modified carbon paste and membrane sensors for the determination of benzethonium chloride and some anionic surfactants (SLES, SDS, and LABSA): Characterization using SEM and AFM.

    Science.gov (United States)

    Issa, Yousry M; Mohamed, Sabrein H; Baset, Mohamed Abd-El

    2016-08-01

    Chemically modified carbon-paste (CMCP) and membrane- sensors based on incorporating benzothonium-tetraphenylborate (BT-TPB) were constructed for the analysis of benzethonium chloride, and some other surfactants such as sodium lauryl ether sulphate (SLES), sodium dodecyl sulphate (SDS), and linear alkylbenzene sulphonic acid (LABSA). All sensors showed good sensitivity and reverse wide linearity over a concentration range of 5.97×10(-7) to 1.00×10(-3) and 5.96×10(-7) to 3.03×10(-3)molL(-1) with limit of detection of 3.92×10(-7)and 3.40×10(-7)molL(-1) for membrane and chemically modified carbon paste sensors, respectively, with respect to benzethonium chloride (BT.Cl). They could be used over a wide pH range of 2.0-10.0. The thermal coefficients of membrane and CMCP sensors are 5.40×10(-4), 1.17×10(-4)V/°C, respectively. The sensors indicated a wide selectivity over different inorganic cations. The effect of soaking on the surface morphology of the membrane sensor was studied using EDX-SEM and AFM techniques. The response time was shampoo, Touri(®) dishwashing liquid, and waste water). The statistical analysis of the obtained data was studied. PMID:27216669

  5. Study of the roles of chemical modifiers in determining boron using graphite furnace atomic absorption spectrometry and optimization of the temperature profile during atomization

    International Nuclear Information System (INIS)

    The measurement conditions for determining boron using graphite furnace–atomic absorption spectrometry (GF-AAS) were investigated. Differences in the boron absorbance profiles were found using three different commercially available GF-AAS instruments when the graphite atomizers in them were not tuned. The boron absorbances found with and without adjusting the graphite atomizers suggested that achieving an adequate absorbance for the determination of boron requires a sharp temperature profile that overshoots the target temperature during the atomization process. Chemical modifiers that could improve the boron absorbance without the need for using coating agents were tested. Calcium carbonate improved the boron absorbance but did not suppress variability in the peak height. Improvement of boron absorbance was comparatively less using iron nitrate or copper nitrate than using calcium carbonate, but variability in the peak height was clearly suppressed using iron nitrate or copper nitrate. The limit of detection was 0.0026 mg L−1 when iron nitrate was used. It appears that iron nitrate is a useful new chemical modifier for the quick and simple determination of boron using GF-AAS. (author)

  6. Use of sodium tungstate as a permanent chemical modifier for slurry sampling electrothermal atomic absorption spectrometric determination of indium in soils

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Garcia, Ignacio; Rivas, Ricardo E.; Hernandez-Cordoba, Manuel [University of Murcia, Department of Analytical Chemistry, Faculty of Chemistry, Murcia (Spain)

    2008-06-15

    A number of chemical modifiers have been assessed for the direct determination of indium in soils using electrothermal atomic absorption spectrometry and slurry sampling. The best results were obtained when the graphite atomizer was impregnated with sodium tungstate, which acts as a permanent chemical modifier. Slurries were prepared by suspending 100 mg sample in a solution containing 1% (v/v) concentrated nitric acid and 10% (v/v) concentrated hydrofluoric acid and then 15-{mu}L aliquots were directly introduced into the atomizer. Standard indium solutions prepared in the suspension medium in the range 4-80 {mu}g L{sup -1} indium were used for calibration. The relative standard deviation for ten consecutive measurements of a 40 {mu}g L{sup -1} indium solution was 2.8%. The limit of detection in soils was 0.1 {mu}g g{sup -1}. The reliability of the procedures was confirmed by analysing two standard reference materials and by using an alternative procedure. (orig.)

  7. Electrochemical properties of the hexacyanoferrate(II)–ruthenium(III) complex immobilized on silica gel surface chemically modified with zirconium(IV) oxide

    Energy Technology Data Exchange (ETDEWEB)

    Panice, Lucimara B.; Oliveira, Elisangela A. de; Filho, Ricardo A.D. Molin; Oliveira, Daniela P. de [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Lazarin, Angélica M., E-mail: amlazarin2@uem.br [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Andreotti, Elza I.S.; Sernaglia, Rosana L. [Departamento de Química, Universidade Estadual de Maringá, Av. Colombo, 5790, 87020-900 Maringá, PR (Brazil); Gushikem, Yoshitaka [Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, 13084-971 Campinas, São Paulo (Brazil)

    2014-10-15

    Highlights: • The cyano-bridged mixed valence ruthenium composite material was synthesized. • This newly synthesized compound was incorporated into a carbon paste electrode. • The electrode did not show significant changes in response after six months of use. • The modified electrode is very stable and reproducible. • The electrode sensor was successfully applied for ascorbic acid determination. - Abstract: The chemically modified silica gel with zirconium(IV) oxide was used to immobilize the [Fe(CN){sub 6}]{sup 4−} complex ion initially. The reaction of this material with [Ru(edta)H{sub 2}O]{sup −} complex ion formed the immobilized cyano-bridged mixed valence ruthenium complex, (≡Zr){sub 5}[(edta)RuNCFe(CN){sub 5}]. This material was incorporated into a carbon paste electrode and, its electrochemical properties were investigated. However, for an ascorbic acid solution, an enhancement of the anodic peak current was detected due to electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, with a good repeatability. The modified electrode is very stable and reproducible. The sensor was applied for ascorbic acid determination in pharmaceutical preparation with success.

  8. Application of chemical modified starch in adhesives%经化学改性后淀粉在胶粘剂中的应用

    Institute of Scientific and Technical Information of China (English)

    姜青松; 黄庆东; 李广源; 韦志福; 李军生; 胡孝勇

    2015-01-01

    The starch adhesives is a kind of environment friendly and renewable biomass products, which have broad application prospects. Starch has the disadvantages of low bond strength, poor water resistance, slow drying rate, etc,. and needs to be modified. In this paper, using the oxidation, esterification, crosslinking and grafting as the chemical methods to modify starch, the applications of the modified starch in adhesives and their development trend were reviewed.%淀粉胶粘剂是一种环保型、可再生型生物质产品,具有广阔应用前景。淀粉具有粘接强度低、耐水性差、干燥速度慢等缺点,需对其进行化学改性。本文综述了淀粉经氧化、酯化、交联化、接枝化等化学手段改性后在胶粘剂中的应用以及发展趋势。

  9. Greenhouse problem in the Amazon jungle clearing

    International Nuclear Information System (INIS)

    This paper discusses the contribution of Amazon jungle clearing to the greenhouse problem and makes an assessment of long-run prospects. The introductory sections pose the problem from both international and Brazilian perspectives. The next section describes major features of the Amazonia ecosystems and presents methods and evidence on deforestation and on its impact on carbon dioxide emissions. Based upon cross-section information for a sample of municipalities in the Brazilian Amazon, the following section estimates elasticities of deforestation in relation to major economic factors- government policies included- and uses them to make projections for the future pace of deforestation. The last section discusses policy alternatives to slow down forest conversion

  10. Institutions and sustainable development in Amazon region

    OpenAIRE

    Bastos, Ana Paula; Monteiro, Maurilio

    2011-01-01

    This article analyses recent efforts to create a different institutional framework in Pará State, Brazilian Amazon to promote sustainable development. The region is economically peripheral to capitalism. Historically, Amazon river delta has been used as source of raw materials since XVII century, but only from the 1970’s, when roads were built, is been massively occupied by frontier activities like timber, mining, cattle and more recently soya beans. The economy is driven by primary a...

  11. Rethinking the strategy of Amazon.com

    OpenAIRE

    Heng, Michael S.H.

    2001-01-01

    The strategic challenge facing Amazon.com is that it is not able to convince the investment community that it is able to generate profits in the long run. The doubt of investors is well grounded. This paper argues that Amazon should make a strategic shift to operate as a provider of technical services and business consulting in the area of business-to-consumer e-commerce. At the same time it should reduce the range of the items sold on-line to, say, books and CDs, and treat this part of its b...

  12. Electrochemical behavior of folic acid at calixarene based chemically modified electrodes and its determination by adsorptive stripping voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Vaze, Vishwanath D. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India); Srivastava, Ashwini K. [Department of Chemistry, University of Mumbai, Vidyanagari, Santacruz (East), Mumbai 400098 (India)], E-mail: aksrivastava@chem.mu.ac.in

    2007-12-31

    Voltammetric behavior of folic acid at plain carbon paste electrode and electrode modified with calixarenes has been studied. Two peaks for irreversible oxidation were observed. Out of the three calixarenes chosen for modification of the electrodes, p-tert-butyl-calix[6]arene modified electrode (CME-6) was found to have better sensitivity for folic acid. Chronocoulometric and differential pulse voltammetric studies reveal that folic acid can assemble at CME-6 to form a monolayer whose electron transfer rate is 0.00273 s{sup -1} with 2-electron/2-proton transfer for the peak at +0.71 V against SCE. An adsorption equilibrium constant of 5 x 10{sup 3} l/mol for maximum surface coverage of 2.89 x 10{sup -10} mol/cm{sup 2} was obtained. The current is found to be rectilinear with concentration by differential pulse voltammetry. However, linearity in the lower range of concentration 8.79 x 10{sup -12} M to 1.93 x 10{sup -9} M with correlation coefficient of 0.9920 was achieved by adsorptive stripping voltammetry. The limit of detection obtained was found to be 1.24 x 10{sup -12} M. This method was used for the determination of folic acid in a variety of samples, viz. serum, asparagus, spinach, oranges and multivitamin preparations.

  13. Chemical modification of poly(ethylene terephthalate) and immobilization of the selected enzymes on the modified film

    International Nuclear Information System (INIS)

    Poly(ethylene terephthalate) (PET) film was modified by reaction with hydrazine (HD), ethylenediamine (EDA), 1,2-diaminopropane (1,2-DAP) and 1,3-diaminopropane (1,3-DAP). The maximal amount of amine functionalities introduced in the chosen conditions on the surface was found as 0.07, 3.35, 0.76 and 1.99 nmol cm-2 for HD, EDA, 1,2-DAP and 1,3-DAP respectively. During the modification process etching of the sample and an increase of stiffness takes place. FTIR-ATR spectra prove that the surface chemistry after modification in amine solution is very complex. The lack of clear correlation between the surface tension and surface concentration of amine functionalities seems to confirm that. For immobilization purpose invertase, laccase and tyrosinase were used. The amount of covalently attached proteins at first increases with the increase of surface concentration of amine groups but after reaching a certain level of amine groups, decrease of the immobilization level was observed. All enzymes tested showed highest activity for a moderate level of aminolysis and this activity had the highest values for EDA-modified PET.

  14. Chemical modification of poly(ethylene terephthalate) and immobilization of the selected enzymes on the modified film

    Energy Technology Data Exchange (ETDEWEB)

    Irena, Gancarz, E-mail: irena.gancarz@pwr.wroc.pl [Department of Chemistry, Wroclaw University of Technology, 50-370 Wroclaw (Poland); Jolanta, Bryjak; Karolina, Zynek [Department of Chemistry, Wroclaw University of Technology, 50-370 Wroclaw (Poland)

    2009-07-15

    Poly(ethylene terephthalate) (PET) film was modified by reaction with hydrazine (HD), ethylenediamine (EDA), 1,2-diaminopropane (1,2-DAP) and 1,3-diaminopropane (1,3-DAP). The maximal amount of amine functionalities introduced in the chosen conditions on the surface was found as 0.07, 3.35, 0.76 and 1.99 nmol cm{sup -2} for HD, EDA, 1,2-DAP and 1,3-DAP respectively. During the modification process etching of the sample and an increase of stiffness takes place. FTIR-ATR spectra prove that the surface chemistry after modification in amine solution is very complex. The lack of clear correlation between the surface tension and surface concentration of amine functionalities seems to confirm that. For immobilization purpose invertase, laccase and tyrosinase were used. The amount of covalently attached proteins at first increases with the increase of surface concentration of amine groups but after reaching a certain level of amine groups, decrease of the immobilization level was observed. All enzymes tested showed highest activity for a moderate level of aminolysis and this activity had the highest values for EDA-modified PET.

  15. Chemical modification of poly(ethylene terephthalate) and immobilization of the selected enzymes on the modified film

    Science.gov (United States)

    Irena, Gancarz; Jolanta, Bryjak; Karolina, Zynek

    2009-07-01

    Poly(ethylene terephthalate) (PET) film was modified by reaction with hydrazine (HD), ethylenediamine (EDA), 1,2-diaminopropane (1,2-DAP) and 1,3-diaminopropane (1,3-DAP). The maximal amount of amine functionalities introduced in the chosen conditions on the surface was found as 0.07, 3.35, 0.76 and 1.99 nmol cm -2 for HD, EDA, 1,2-DAP and 1,3-DAP respectively. During the modification process etching of the sample and an increase of stiffness takes place. FTIR-ATR spectra prove that the surface chemistry after modification in amine solution is very complex. The lack of clear correlation between the surface tension and surface concentration of amine functionalities seems to confirm that. For immobilization purpose invertase, laccase and tyrosinase were used. The amount of covalently attached proteins at first increases with the increase of surface concentration of amine groups but after reaching a certain level of amine groups, decrease of the immobilization level was observed. All enzymes tested showed highest activity for a moderate level of aminolysis and this activity had the highest values for EDA-modified PET.

  16. Novel epoxy-silicone thermolytic transparent packaging adhesives chemical modified by ZnO nanowires for HB LEDs

    International Nuclear Information System (INIS)

    A novel high transparent thermolytic epoxy-silicone for high-brightness light-emitting diode (HB-LED) is introduced, which was synthesized by polymerization using silicone matrix via diglycidyl ether bisphenol-A epoxy resin (DGEBA) as reinforcing agent, and filling ZnO nanowires to modify thermal conductivity and control refractive index of the hybrid material. The interactions of ZnO nanowires with polymers are mediated by the ligands attached to the nanoparticles. Thus, the ligands markedly influence the properties of ZnO nanowires/epoxy-silicone composites. The refractive indices of the prepared hybrid adhesives can be tuned by the ZnO nanowires from 1.4711 to 1.5605. Light transmittance can be increased by 20% from 80 to 95%. The thermal conductivity of the transparent packaging adhesives is 0.89-0.90 W/mK.

  17. Novel epoxy-silicone thermolytic transparent packaging adhesives chemical modified by ZnO nanowires for HB LEDs

    Energy Technology Data Exchange (ETDEWEB)

    He Ying, E-mail: yinghe@staff.shu.edu.c [Shanghai University, Department of Polymer Materials, School of Materials Science and Engineering (China); Wang Junan [Shanghai University, Institute of Materials, School of Materials Science and Engineering (China); Pei Changlong; Song Jizhong; Zhu Di; Chen Jie [Shanghai University, Department of Polymer Materials, School of Materials Science and Engineering (China)

    2010-10-15

    A novel high transparent thermolytic epoxy-silicone for high-brightness light-emitting diode (HB-LED) is introduced, which was synthesized by polymerization using silicone matrix via diglycidyl ether bisphenol-A epoxy resin (DGEBA) as reinforcing agent, and filling ZnO nanowires to modify thermal conductivity and control refractive index of the hybrid material. The interactions of ZnO nanowires with polymers are mediated by the ligands attached to the nanoparticles. Thus, the ligands markedly influence the properties of ZnO nanowires/epoxy-silicone composites. The refractive indices of the prepared hybrid adhesives can be tuned by the ZnO nanowires from 1.4711 to 1.5605. Light transmittance can be increased by 20% from 80 to 95%. The thermal conductivity of the transparent packaging adhesives is 0.89-0.90 W/mK.

  18. Selective catalytic conversion of ethanol to basic chemicals over phosphorus-modified H-ZSM-5 zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Danilina, N.; Reschetilowski, W. [Technische Univ. Dresden (Germany). Inst. fuer Technische Chemie; Toufar, H. [TRICAT Zeolites, Bitterfeld (Germany)

    2006-07-01

    The activity and selectivity of unmodified and phosphorus-modified H-ZSM-5 zeolites (Si/Al = 11) in the conversion of ethanol was studied. The post-synthesis modification of H-ZSM-5 was done using phosphoric acid; the phosphorus loading was varied between 0.33 and 1.3 wt.-%. The catalytic tests were performed at 450 C and under atmospheric pressure in a plug-flow reactor. All catalyst samples were characterized with XRD, AAS, EDX, IR, and 31P MAS NMR. The acidic properties were determined with in situ FTIR measurements of temperature-programmed ammonia-desorption. The incorporation of phosphorus in H-ZSM-5 zeolites by post-synthesis modification leads to highly active and selective catalysts for the conversion of ethanol to aromatics. The conversion of ethanol increases to up to 100 % and the selectivity to aromatics to maximally 80 wt.-%. (orig.)

  19. Chemically modified polymeric resins for solid-phase extraction and group separation prior to analysis by liquid or gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, L.W.

    1993-07-01

    Polystyrene divinylbenzene was modified by acetyl, sulfonic acid, and quaternary ammonium groups. A resin functionalized with an acetyl group was impregnated in a PTFE membrane and used to extract and concentrate phenolic compounds from aqueous samples. The acetyl group created a surface easily wetted, making it an efficient adsorbent for polar compounds in water. The membrane stabilized the resin bed. Partially sulfonated high surface area resins are used to extract and group separate an aqueous mixture of neutral and basic organics; the bases are adsorbed electrostatically to the sulfonic acid groups, while the neutraons are adsorbed hydrophobically. A two-step elution is then used to separate the two fractions. A partially functionalized anion exchange resin is used to separate organic acids and phenols from neutrals in a similar way. Carboxylic acids are analyzed by HPLC and phenols by GC.

  20. Nano-hydroxyapatite colloid suspension coated on chemically modified porous silicon by cathodic bias: a suitable surface for cell culture

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Alejandra [Escuela de Quimica, Universidad de Costa Rica, 2060 (Costa Rica); Centro de Electroquimica y Energia Quimica de la Universidad de Costa Rica (CELEQ), Universidad de Costa Rica, 2060 (Costa Rica); Gonzalez, Jerson [Escuela de Quimica, Universidad de Costa Rica, 2060 (Costa Rica); Garcia-Pineres, Alfonso [Escuela de Quimica, Universidad de Costa Rica, 2060 (Costa Rica); Centro de Investigacion en Biologia Celular y Molecular (CIBCM), Universidad de Costa Rica, 2060 (Costa Rica); Montero, Mavis L. [Escuela de Quimica, Universidad de Costa Rica, 2060 (Costa Rica); Centro de Electroquimica y Energia Quimica de la Universidad de Costa Rica (CELEQ), Universidad de Costa Rica, 2060 (Costa Rica); Centro de Ciencia e Ingenieria en Materiales (CICIMA), Universidad de Costa Rica, 2060 (Costa Rica)

    2011-06-15

    The properties of porous silicon make it an interesting material for biological applications. However, porous silicon is not an appropriate surface for cell growth. Surface modification is an alternative that could afford a bioactive material. In this work, we report a method to yield materials by modification of the porous silicon surface with hydroxyapatite of nanometric dimensions, produced using an electrochemical process and coated on macroporous silicon substrates by cathodic bias. The chemical nature of the calcium phosphate deposited on the substrates after the experimental process and the amount of cell growth on these surfaces were characterized. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Organofunctionalized Amazon smectite for dye removal from aqueous medium-Kinetic and thermodynamic adsorption investigations

    International Nuclear Information System (INIS)

    The objective of this study is to examine the adsorption behavior of Sumifix Brilliant Orange 3R textile dye from aqueous solution on smectite sample, an abundant Amazon clay. The original smectite clay mineral has been collected from Amazon region, Brazil. The compound 2-aminomethylpyridine was anchored onto smectite surface by heterogeneous route. The ability of these materials to remove the Sumifix Brilliant Orange 3R textile dye from aqueous solution was followed by a series of adsorption isotherms, using a batchwise process. The maximum number of moles adsorbed was determined to be 1.26 and 2.07 mmol g-1 for natural and modified clay samples, respectively. The energetic effects caused by dye cations adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such dye-nitrogen interactions.

  2. Suspected Lead Poisoning in an Amazon Parrot

    OpenAIRE

    McDonald, Lawrence J.

    1986-01-01

    A double yellow headed Amazon parrot (Amazona ochrocephala tresmariae) of unknown age and sex was examined for an acute onset of anorexia, listlessness, central nervous system signs and diarrhea. A tentative diagnosis of lead toxicosis was achieved based on radiographs, clinical pathology and response to therapy. Chelation therapy (Calcium EDTA) and supportive measures resulted in an uneventful recovery.

  3. Does the Amazon suffer from BSE prevention?

    NARCIS (Netherlands)

    Elferink, E.V.; Nonhebel, S.; Schoot Uiterkamp, A.J.M.

    2007-01-01

    In the last decade, large-scale production of soybeans has been a major driver of the enhanced deforestation in the Brazilian Amazon. We show that these soybeans are mainly exported to the EU to substitute for the BSE related banned meat and bone meal in livestock feed. This strongly suggests a link

  4. Amazon Flooded Forest. Teacher Resource Guide.

    Science.gov (United States)

    Duvall, Todd

    This teacher's resource guide was created to accompany the Amazon Flooded Forest exhibit at the Oregon Zoo. The enclosed lessons and activities are designed to extend into several aspects of daily curriculum including science, math, reading, writing, speaking, and geography. The materials are intended for use in grades 3-6 although most activities…

  5. Deforestation crimes and conflicts in the Amazon

    NARCIS (Netherlands)

    Boekhout van Solinge, T.

    2010-01-01

    This article explores and explains deforestation of the Brazilian Amazon rainforest. It primarily takes a green criminological perspective and looks at the harm that is inflicted on many of the Amazon’s inhabitants, including indigenous populations such as ‘uncontacted’ tribes of hunters-gatherers,

  6. Application of Nation/Cobalt Hexacyanoferrate Chemically Modified Electrodes for the Determination of Electroinactive Cations by Ion Chromatography

    Institute of Scientific and Technical Information of China (English)

    XU,Ji-Ming(徐继明); XIAN,Yue-Zhong(鲜跃仲); SHI,Guo-Yue(施国跃); LI,Jin-Hua(李金花); JIN Li-Tong(金利通)

    2002-01-01

    An amperometric detector based on the chemical modification of Nafion and cobalt(H) hexacyanoferrate(Ⅱ, Ⅲ) thin film (Nafion/Co-CN-Fe) onto a glassy carbon (GC) electrode was firslly developed for the determination of electroinactive cations (Li+, Na+, K+, Rb+, Cs+ and NH4+) in single column ion chromatography. A set of well-defined peaks of electroinactive cation was obtained. The relative standard deviations (RSDs)of - peak height (nA) for these cations were all below 3.8%. The cations were detected conveniently in the linear concentration range of 6.0× 10-6-5.0 × 10-3 mol/L and their correlation coefficients were all above 0.99. Tne detection limiits of the cations were 9.2 × 10- 6 mol/L for Li + , 3.4 ×10-6 mol/L for Na+ , 6.3 × 10-7 mol/L for K+ , 7.8 × 10-7 mol/L for Rb+ , 6.2 × 10-7 mol/L for Cs+ and 6.2 × 10-6 mol/L for NH4+ , at a signal-noise ratio of 3. The method was quick, sensitive, simple and was successfully applied to the analysis of rainwater samples. The electrode was stable for a 2 week period of operation with no evidence of chemical or mechanical deterioration.

  7. Application of Nafion/Cobalt Hexacyanoferrate Chemically Modified Electrodes for the Determination of Electroinactive Cations by Ion Chromatography

    Institute of Scientific and Technical Information of China (English)

    徐继明; 鲜跃仲; 等

    2002-01-01

    An amperometric detector based on the chemical modification of Nafion and cobalt(Ⅱ) hexacyanoferrate(Ⅱ,Ⅲ)thin film (Nafion /Co-CN-Fe) onto a glassy carbon(GC) electrode was firstly developed for the determination of electroinactive cations (Li+,Na+,K+,Rb+,Cs+,and NH4+)in single column ion cgrinatography,A set of well-defined peaks of electroinactive cation was obtained ,The relative standard deviations (RSDs) of chromatographic peak height(nA) for these cations were all below 3.8% .The cations were detected convenivently in the linear concentration ragne of 6.0×10-6--5.0×10-3 mol/L and their correlation coefficients were all above 0.99 .The detection limits of the cations were 9.2×107 mol/L for K+,7.8×107mol/L for Rb+,6.2×107mol/L for Cs+ and 6.2×106mol/L for NH4+ ,at a signal-noise ratio of 3. The method was quick,sensitive,simple and was successfully applied to the analysis of rainwater samples,The electrode was stable for a 2 week period of operation with no evidence of chemical of mechanical deterioration.

  8. Radium removal from aqueous solutions by adsorption on non-treated and chemically modified biomass by-product

    International Nuclear Information System (INIS)

    The adsorption efficiency of a biomass by-product (olive cake) regarding the removal of radium (226Ra) from aqueous solutions has been investigated prior and after its chemical treatment. The chemical treatment of the biomass by-product included phosphorylation and MnO2-coating. The separation/removal efficiency has been studied as a function of pH, salinity (NaCl) and calcium ion concentration (Ca2+) in solution. Evaluation of the experimental data shows clearly that the phosphorylated biomass by-product presents the highest adsorption capacity and efficiency followed by the MnO2-coated material and the non-treated biomass by-product. However, regarding the effect of salinity and the presence of competitive cations (e.g. Ca2+) on the adsorption/removal efficiency, the MnO2-coated material shows the lowest decline in efficiency (only 2 % of the relative adsorption efficiency) followed by the non-treated and the phosphorylated biomass by-product. The results of the present study indicate that depending on the physicochemical characteristics of the radium-contaminated water, all three types of the biomass by-product could be effectively used for the treatment of radium-contaminated waters. Nevertheless, the MnO2-coated material is expected to be the most effective adsorbent and an alternative to MnO2 resins for the treatment of environmentally relevant waters. (author)

  9. Lateritinga project: a geochemical orientation study for Amazon lateritic

    International Nuclear Information System (INIS)

    The aim of this project is the development of systematic geochemical orientation survey in lateritic weathered terrain, like those form Amazon Region. The main selected targets (sheets) are: Turiacu, Cajuapara and Serra dos Carajas, with 690 samples collected (soils and lateritic rocks). For the Aurizona-Serra do Pirocaua target (Turiacu sheet), within the purpose of this work, 49 samples were collected in a 100x 200m regular grid. From all samples the fraction minor than 200 mesh was taken to analyses (by XRF, AA, OES, ICP and fire assay) for SiO sub(2), Fe sub(2) O sub(3), TiO sub(2), P sub(2) O sub(5), Sr, Ba, Y, Nb, Zr, Ga, Sc, Ni, Co, Cr, Cu, Mn, V, As, Bi, Pt, Pd, Th, Au and REE, as well for their mineralogy by XRD. The chemical results were submitted to statistical treatment with the Geoquant-software for IBM-compatible microcomputer. (author)

  10. Chemical analyses of hydroxyapatite formation on SAM surfaces modified with COOH, NH(2), CH(3), and OH functions.

    Science.gov (United States)

    Hirata, Isao; Akamatsu, Mai; Fujii, Eri; Poolthong, Suchit; Okazaki, Masayuki

    2010-08-01

    Hydroxyapatite formation was examined at the surface of self-assembled monolayers (SAMs) modified with four functional groups, -COOH, -NH(2), -CH(3), and -OH. For COOH-SAM and NH(2)-SAM, scanning electron spectroscopic observation showed that flake-like sheet crystals covered the whole wafer and small broccoli-like crystals were observed occasionally on the flake-like crystal base layer. For CH(3)-SAM and OH-SAM, no flake-like sheet crystals were observed; broccoli-like crystals were observed in a dispersed manner for CH(3)-SAM, but in localized spots for OH-SAM. X-ray diffraction patterns showed a strong apatite pattern oriented toward the c-axis direction for COOH-SAM. ESCA analysis revealed distinct Ca, P, O peaks for COOH-, NH(2)-, CH(3)-, and OH-SAM. Surface plasmon resonance (SPR) analysis indicated that during the supply of supersaturated calcium phosphate solution, the deposition of precipitates increased monotonically with time for COOH-SAM, increased slightly for NH(2)-SAM, but little increase in deposition was detected for CH(3)-SAM and OH-SAM.

  11. The Role of Genotypes That Modify the Toxicity of Chemical Mutagens in the Risk for Myeloproliferative Neoplasms

    Directory of Open Access Journals (Sweden)

    Carol Ann Gross-Davis

    2015-02-01

    Full Text Available Background: The etiology of myeloproliferative neoplasms (MPN (polycythemia vera; essential thrombocythemia; primary myelofibrosis is unknown, however they are associated with a somatic mutation—JAK2 V617F—suggesting a potential role for environmental mutagens. Methods: We conducted a population-based case-control study in three rural Pennsylvania counties of persons born 1921–1968 and residing in the area between 2000–2008. Twenty seven MPN cases and 292 controls were recruited through random digit dialing. Subjects were genotyped and odds ratios estimated for a select set of polymorphisms in environmentally sensitive genes that might implicate specific environmental mutagens if found to be associated with a disease. Results: The presence of NAT2 slow acetylator genotype, and CYP1A2, GSTA1, and GSTM3 variants were associated with an average 3–5 fold increased risk. Conclusions: Exposures, such as to aromatic compounds, whose toxicity is modified by genotypes associated with outcome in our analysis may play a role in the environmental etiology of MPNs.

  12. Chemically modified tetracycline (COL-3) improves survival if given 12 but not 24 hours after cecal ligation and puncture.

    Science.gov (United States)

    Halter, Jeffrey M; Pavone, Lucio A; Steinberg, Jay M; Gatto, Louis A; DiRocco, Joseph; Landas, Steve; Nieman, Gary F

    2006-12-01

    Sepsis can result in excessive and maladaptive inflammation that is responsible for more than 215,00 deaths per year in the United State alone. Current strategies for reducing the morbidity and mortality associated with sepsis rely on treatment of the syndrome rather than prophylaxis. We have been investigating a modified tetracycline, COL-3, which can be given prophylactically to patients at high risk for developing sepsis. Our group has shown that COL-3 is very effect at preventing the sequelae of sepsis if given before or immediately after injury in both rat and porcine sepsis models. In this study, we wanted to determine the "treatment window" for COL-3 after injury at which it remains protective. Sepsis was induced by cecal ligation and puncture (CLP). Rats were anesthetized and placed into five groups: CLP (n = 20) = CLP without COL-3, sham (n = 5) = surgery without CLP or COL-3, COL3@6h (n = 10) = COL-3 given by gavage 6 h after CLP, COL3@12h (n = 10) = COL-3 given by gavage 12 h after CLP, and COL3@24h (n = 20) = COL-3 given by gavage 24 h after CLP. COL-3 that was given at 6 and 12 h after CLP significantly improved survival as compared with the CLP and the CLP@24h groups. Improved survival was associated with a significant improvement in lung pathology assessed morphologically. These data suggest that COL-3 can be given up to 12 h after trauma and remain effective.

  13. Long-Term Performance of Chemically and Physically Modified Activated Carbons in Air Cathodes of Microbial Fuel Cells

    KAUST Repository

    Zhang, Xiaoyuan

    2014-07-31

    © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Activated carbon (AC) is a low-cost and effective catalyst for oxygen reduction in air cathodes of microbial fuel cells (MFCs), but its performance must be maintained over time. AC was modified by three methods: 1)pyrolysis with iron ethylenediaminetetraacetic acid (AC-Fe), 2)heat treatment (AC-heat), and 3)mixing with carbon black (AC-CB). The maximum power densities after one month with these AC cathodes were 35% higher with AC-Fe (1410±50mW m-2) and AC-heat (1400±20mW m-2), and 16% higher with AC-CB (1210±30mW m-2) than for plain AC (1040±20mW m-2), versus 1270±50mW m-2 for a Pt control. After 16months, the Pt cathodes produced only 250±10mW m-2. However, the AC-heat and AC-CB cathodes still produced 960-970mW m-2, whereas plain AC produced 860±60mW m-2. The performance of the AC cathodes was restored to >85% of the initial maximum power densities by cleaning with a weak acid solution. Based on cost considerations among the AC materials, AC-CB appears to be the best choice for long-term performance.

  14. Metalorganic chemical vapor deposition of anatase titanium dioxide on Si: Modifying the interface by pre-oxidation

    Science.gov (United States)

    Sandell, A.; Andersson, M. P.; Johansson, M. K.-J.; Karlsson, P. G.; Alfredsson, Y.; Schnadt, J.; Siegbahn, H.; Uvdal, P.

    2003-04-01

    The formation of TiO 2 films on clean and pre-oxidized Si(1 1 1) through chemical vapor deposition of titanium(IV) isopropoxide (TTIP) in ultra-high vacuum has been examined by synchrotron radiation photoelectron spectroscopy, X-ray absorption spectroscopy (XAS) and scanning tunneling microscopy. In both cases, TTIP deposition at 500 °C eventually results in an anatase TiO 2 film with a carbon-free surface and the surface morphology of the anatase films is very similar. By using a novel way of combining photoemission and XAS data, it is demonstrated that the two situations have substantially different interfacial properties. Pre-oxidation of the surface at 500 °C passivates the surface so that the thickness of the amorphous TiSi xO y interface layer decreases from 30-35 to 15-25 Å and eliminates the formation of interfacial carbon completely.

  15. Effect of calf feeding regimes and diet EDTA on physico-chemical characteristics of veal stored under modified atmospheres.

    Science.gov (United States)

    Gariépy, C; Delaquis, P J; Pommier, S; De Passillé, A M; Fortin, J; Lapierre, H

    1998-05-01

    Physico-chemical characteristics of veal from 30 calves allotted to five different rations with respect to iron bioavailability were evaluated at packaging and after 2 and 4 weeks of storage under both 100% CO(2) and 100% N(2). The five diets were 'Milk', 'Grain', 'Mix' (combination of Milk and Grain) and 'Mix + EDTA' and 'Grain + EDTA' where 15 mg EDTA were added per mg Fe in the feed concentrate. Diet EDTA was generally more influential on veal quality than storage treatments. The chelator caused an unexpected pH drop in veal stored four weeks irrespective of storage conditions (p ≤ 0.05). However, the colour, texture and flavour of meat from animals fed EDTA in the Grain- and Mix-ration was equivalent to that of Milk-fed veal (p ≤ 0.05). The EDTA treatments also improved the appearance of veal under anoxic atmospheres. Upon storage however, the chelator increased veal drip losses (p ≤ 0.05) and also cooking losses from Grain-fed calves (p ≤ 0.05). Packaging under CO(2) decreased pH (p ≤ 0.05) and increased drip losses (p ≤ 0.05) but did not alter other physico-chemical parameters. Dietary treatments had no effect on shear forces (p > 0.05) which decreased after two weeks in storage (p ≤ 0.05) independent of gas atmospheres. Overall, the quality characteristics of pale veal were obtained following addition of EDTA in Grain- and Mix-fed animals and were maintained in storage. This approach looks promising for the veal industry but warrants further research. PMID:22063188

  16. Extracellular biosynthesis of gadolinium oxide (Gd2O3 nanoparticles, their biodistribution and bioconjugation with the chemically modified anticancer drug taxol

    Directory of Open Access Journals (Sweden)

    Shadab Ali Khan

    2014-03-01

    Full Text Available As a part of our programme to develop nanobioconjugates for the treatment of cancer, we first synthesized extracellular, protein-capped, highly stable and well-dispersed gadolinium oxide (Gd2O3 nanoparticles by using thermophilic fungus Humicola sp. The biodistribution of the nanoparticles in rats was checked by radiolabelling with Tc-99m. Finally, these nanoparticles were bioconjugated with the chemically modified anticancer drug taxol with the aim of characterizing the role of this bioconjugate in the treatment of cancer. The biosynthesized Gd2O3 nanoparticles were characterized by UV–vis spectroscopy, transmission electron microscopy (TEM, X-ray diffraction (XRD and X-ray photoemission spectroscopy (XPS. The Gd2O3–taxol bioconjugate was confirmed by UV–vis spectroscopy and fluorescence microscopy and was purified by using high performance liquid chromatography (HPLC.

  17. Determination of vanadium(V) by direct automatic potentiometric titration with EDTA using a chemically modified electrode as a potentiometric sensor.

    Science.gov (United States)

    Quintar, S E; Santagata, J P; Cortinez, V A

    2005-10-15

    A chemically modified electrode (CME) was prepared and studied as a potentiometric sensor for the end-point detection in the automatic titration of vanadium(V) with EDTA. The CME was constructed with a paste prepared by mixing spectral-grade graphite powder, Nujol oil and N-2-naphthoyl-N-p-tolylhydroxamic acid (NTHA). Buffer systems, pH effects and the concentration range were studied. Interference ions were separated by applying a liquid-liquid extraction procedure. The CME did not require any special conditioning before using. The electrode was constructed with very inexpensive materials and was easily made. It could be continuously used, at least two months without removing the paste. Automatic potentiometric titration curves were obtained for V(V) within 5 x 10(-5) to 2 x 10(-3)M with acceptable accuracy and precision. The developed method was applied to V(V) determination in alloys for hip prosthesis. PMID:18970248

  18. The Enhanced Physico-Chemical and Electrochemical Properties for Surface Modified NiO Cathode for Molten Carbonate Fuel Cells (MCFCs)

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hee Seon; Kim, Keon [Korea Univ., Seoul (Korea, Republic of); Yi, Cheolwoo [Sungshin Women' s Univ., Seoul (Korea, Republic of)

    2014-05-15

    The nickel oxide, the most widely used cathode material for the molten carbonate fuel cell (MCFC), has several disadvantages including NiO dissolution, poor mechanical strength, and corrosion phenomena during MCFC operation. The surface modification of NiO with lanthanum maintains the advantages, such as performance and stability, and suppresses the disadvantages of NiO cathode because the modification results in the formation of LaNiO{sub 3} phase which has high conductivity, stability, and catalytic activity. As a result, La-modified NiO cathode shows low NiO dissolution, high degree of lithiation, and mechanical strength, and high cell performance and catalytic activity in comparison with the pristine NiO. These enhanced physico-chemical and electrochemical properties and the durability in marine environment allow MCFC to marine application as a auxiliary propulsion system.

  19. Review of long-term adverse effects associated with the use of chemically-modified animal and nonanimal source hyaluronic acid dermal fillers

    Directory of Open Access Journals (Sweden)

    Paul C Edwards

    2007-01-01

    Full Text Available Paul C Edwards1, John E Fantasia21Associate Professor (Clinical, Department of Periodontics and Oral Medicine, Pathology and Oncology, University of Michigan School of Dentistry, Ann Arbor MI, USA; 2Chief, Division of Oral Pathology, Department of Dental Medicine, Long Island Jewish Medical Center, New Hyde Park, NY, USAAbstract: Although only recently introduced, chemically-modified hyaluronic acid dermal fillers have gained widespread acceptance as “redefining” dermal fillers in the fields of dermatology and cosmetic facial surgery. Although hyaluronic acid-based dermal fillers have a low overall incidence of long term side effects, occasional adverse outcomes, ranging from chronic lymphoplasmacytic inflammatory reactions to classic foreign body-type granulomatous reactions have been documented. These long-term adverse events are reviewed.Keywords: hyaluronic acid, Restylane®, Hylaform®, injectable dermal filler, foreign body reaction, granuloma

  20. Electron transfer modifies chemical properties of C70 fullerene surface: An ab initio molecular dynamics study of C70O3 molozonides doped with light atoms

    Science.gov (United States)

    Bil, Andrzej; Hutter, Jürg; Morrison, Carole A.

    2014-06-01

    Light metal atoms such as Li, K (electronic state 2S1/2) or Ca (1S0) encapsulated in a C70 cage considerably modifies the chemical properties of the fullerene surface due to metal-to-cage electron transfer. H-doped and anion ozonide systems were also considered to validate the electron transfer hypothesis. The relative stabilities of the eight isomers of the C70O3 molozonide series at room temperature depend on the identity of the endohedral guest, as was the preferred channel for thermal decomposition. No electron transfer was observed for the complex N@C70 where the fullerene acts as an inert container for the 4S3/2 radical.

  1. Fatigue behavior of Ti-6Al-4V alloy in saline solution with the surface modified at a micro- and nanoscale by chemical treatment.

    Science.gov (United States)

    Claros, Cesar Adolfo Escobar; Oliveira, Diego Pedreira; Campanelli, Leonardo Contri; Pereira da Silva, Paulo Sergio Carvalho; Bolfarini, Claudemiro

    2016-10-01

    This work evaluated the influence of the surface modification using acid etching combined with alkaline treatment on the fatigue strength of Ti-6Al-4V ELI alloy. The topography developed by chemical surface treatments (CST) was examined by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Increased roughness and effective surface area were investigated and compared with the Ti-6Al-4V samples without modification. Surface composition was analyzed by energy dispersive X-ray spectroscopy (EDS). Axial fatigue resistance of polished and modified surfaces was determined by stepwise load increase tests and staircase test method. Light microscopy and SEM were employed to examine the fracture surface of the tested specimens. According to the results, a similar fatigue behavior was found and a negligible difference in the fatigue crack nucleation was observed for the Ti-6Al-4V with CST in comparison to the samples without treatment. PMID:27287139

  2. Low temperature deposition and effect of plasma power on tin oxide thin films prepared by modified plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    This work presents low temperature (200 and 300 deg. C) thin film deposition of tin oxide (SnO2) using modified plasma enhanced chemical vapor deposition as a function of radio frequency power (100 - 500 W). Stannic chloride (SnCl4) was used as precursor and oxygen (O2, 300 SCCM) as reactant gas. Fine granular morphology was observed with tetragonal rutile structure grown along the [110] direction, at all the deposition conditions. Higher plasma power resulted in smoother morphology, improved crystallinity, and enhanced conductivity. Electrical resistivity value of as low as ∼0.01 Ω cm was obtained at the deposition temperature of 300 deg. C and 250 W of plasma power

  3. Cysteine-10 on 17 β -Hydroxysteroid Dehydrogenase 1 Has Stabilizing Interactions in the Cofactor Binding Region and Renders Sensitivity to Sulfhydryl Modifying Chemicals.

    Science.gov (United States)

    Nashev, Lyubomir G; Atanasov, Atanas G; Baker, Michael E; Odermatt, Alex

    2013-01-01

    17 β -Hydroxysteroid dehydrogenase type 1 (17 β -HSD1) catalyzes the conversion of estrone to the potent estrogen estradiol. 17 β -HSD1 is highly expressed in breast and ovary tissues and represents a prognostic marker for the tumor progression and survival of patients with breast cancer and other estrogen-dependent tumors. Therefore, the enzyme is considered a promising drug target against estrogen-dependent cancers. For the development of novel inhibitors, an improved understanding of the structure-function relationships is essential. In the present study, we examined the role of a cysteine residue, Cys(10), in the Rossmann-fold NADPH binding region, for 17 β -HSD1 function and tested the sensitivity towards sulfhydryl modifying chemicals. 3D structure modeling revealed important interactions of Cys(10) with residues involved in the stabilization of amino acids of the NADPH binding pocket. Analysis of enzyme activity revealed that 17 β -HSD1 was irreversibly inhibited by the sulfhydryl modifying agents N-ethylmaleimide (NEM) and dithiocarbamates. Preincubation with increasing concentrations of NADPH protected 17 β -HSD1 from inhibition by these chemicals. Cys(10)Ser mutant 17 β -HSD1 was partially protected from inhibition by NEM and dithiocarbamates, emphasizing the importance of Cys(10) in the cofactor binding region. Substitution of Cys(10) with serine resulted in a decreased protein half-life, without significantly altering kinetic properties. Despite the fact that Cys(10) on 17 β -HSD1 seems to have limited potential as a target for new enzyme inhibitors, the present study provides new insight into the structure-function relationships of this enzyme. PMID:24348564

  4. Cysteine-10 on 17β-Hydroxysteroid Dehydrogenase 1 Has Stabilizing Interactions in the Cofactor Binding Region and Renders Sensitivity to Sulfhydryl Modifying Chemicals

    Directory of Open Access Journals (Sweden)

    Lyubomir G. Nashev

    2013-01-01

    Full Text Available 17β-Hydroxysteroid dehydrogenase type 1 (17β-HSD1 catalyzes the conversion of estrone to the potent estrogen estradiol. 17β-HSD1 is highly expressed in breast and ovary tissues and represents a prognostic marker for the tumor progression and survival of patients with breast cancer and other estrogen-dependent tumors. Therefore, the enzyme is considered a promising drug target against estrogen-dependent cancers. For the development of novel inhibitors, an improved understanding of the structure-function relationships is essential. In the present study, we examined the role of a cysteine residue, Cys10, in the Rossmann-fold NADPH binding region, for 17β-HSD1 function and tested the sensitivity towards sulfhydryl modifying chemicals. 3D structure modeling revealed important interactions of Cys10 with residues involved in the stabilization of amino acids of the NADPH binding pocket. Analysis of enzyme activity revealed that 17β-HSD1 was irreversibly inhibited by the sulfhydryl modifying agents N-ethylmaleimide (NEM and dithiocarbamates. Preincubation with increasing concentrations of NADPH protected 17β-HSD1 from inhibition by these chemicals. Cys10Ser mutant 17β-HSD1 was partially protected from inhibition by NEM and dithiocarbamates, emphasizing the importance of Cys10 in the cofactor binding region. Substitution of Cys10 with serine resulted in a decreased protein half-life, without significantly altering kinetic properties. Despite the fact that Cys10 on 17β-HSD1 seems to have limited potential as a target for new enzyme inhibitors, the present study provides new insight into the structure-function relationships of this enzyme.

  5. Incorporation of post-translational modified amino acids as an approach to increase both chemical and biological diversity of conotoxins and conopeptides.

    Science.gov (United States)

    Espiritu, Michael J; Cabalteja, Chino C; Sugai, Christopher K; Bingham, Jon-Paul

    2014-01-01

    Bioactive peptides from Conus venom contain a natural abundance of post-translational modifications that affect their chemical diversity, structural stability, and neuroactive properties. These modifications have continually presented hurdles in their identification and characterization. Early endeavors in their analysis relied on classical biochemical techniques that have led to the progressive development and use of novel proteomic-based approaches. The critical importance of these post-translationally modified amino acids and their specific assignment cannot be understated, having impact on their folding, pharmacological selectivity, and potency. Such modifications at an amino acid level may also provide additional insight into the advancement of conopeptide drugs in the quest for precise pharmacological targeting. To achieve this end, a concerted effort between the classical and novel approaches is needed to completely elucidate the role of post-translational modifications in conopeptide structure and dynamics. This paper provides a reflection in the advancements observed in dealing with numerous and multiple post-translationally modified amino acids within conotoxins and conopeptides and provides a summary of the current techniques used in their identification.

  6. Metal modified graphite. An innovative material for systems converting electro-chemical energy; Metallmodifizierter Graphit. Ein innovativer Werkstoff fuer Systeme zur elektrochemischen Energieumwandlung

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Peter

    2007-07-23

    The work deals with metal modification of graphite electrodes in a water-acid electrolyte solution. The target is to improve the catalytic properties of graphite electrodes as they are applied in redox storage batteries for storing electric energy. Different carbon and graphite materials were used and coated electro-chemically with different metals. After being coated with metal the graphite and carbon electrodes were investigated in terms of changing their catalytic properties by means of impedance measurements. It was shown, a metal coating without a prior activation with electro-chemical oxidation-reduction cycles only results in a low or zero increase of the catalytic properties. Investigations at the electrode material glass carbon showed, a prior activation of the electrode surface by means of electro-chemical oxidation-reduction cycles decreases the penetration resistance. The activation of the glass carbon surface prior to the surface coating with metal is favourable to the electro-chemical properties of the metal-modified electrode. All carbon types, which were used in this work, could be activated at a different level by means of electro-chemical oxidation-reduction cycles depending on the carbon type. The investigations further showed that the edge levels of the carbon were activated by means of the electro-chemical oxidation-reduction cycles. The metal precipitation favourably occurs at the activated positions. (orig.) [German] Die Arbeit befasst sich mit der Metallmodifizierung von Graphitelektroden in waessriger saurer Elektrolytloesung. Ziel ist es die katalytischen Eigenschaften von Graphitelektroden wie sie in Redoxspeicherbatterien zur Speicherung von elektrischer Energie eingesetzt werden zu verbessern. Fuer die Untersuchungen wurden unterschiedliche Kohlenstoff und Graphitmaterialien eingesetzt, die elektrochemisch mit verschiedenen Metallen belegt wurden. Die Graphit- und Kohlenstoffelektroden wurden nach der Metallbelegung durch

  7. Geochemistry of the Congo and Amazon river systems. Boron isotopic geochemistry in corals. Continental erosion and ocean pH

    International Nuclear Information System (INIS)

    Two main geological processes control the CO2 concentration in the atmosphere at a geological time scale: CO2 outgasing from the interior of the Earth and CO2 consumption by continental weathering. In the thesis, we initiate two different directions that can be useful to constraint the past climate evolution models. The first one is the extensive study of the largest rivers of the world using the classical geochemical analyses (major and trace elements, Sr-Nd-Pb isotopes) and modelling approaches. The study case of this thesis are the Congo and Amazon Basin. In particular, the coupling between chemical and physical erosion is examined and related to the hydrologic and tectonic parameters. Relief, thus tectonics appear to best control CO2 consumption by rock weathering. The second part of the work is devoted to the measurement of boron isotopic ratio in corals because it may be used as a proxy for paleo-ocean pH. It could thus bring important pieces of information on the global C cycle and climate evolution. The technical part is extensively described and the method applied to the corals from the last interglacial period. Our conclusion is that corals are likely to be influence by early diagenetic changes that modify the boron isotopic composition of corals. We thus propose a test to select the samples. (author)

  8. Prostaglandins can modify gamma-radiation and chemical induced cytotoxicity and genetic damage in vitro and in vivo

    International Nuclear Information System (INIS)

    The effect of prostaglandin E1, E2, and F2 alpha on gamma-radiation, benzo(a)pyrene and diphenylhydantoin-induced cytotoxicity in vivo and genotoxicity in vitro was investigated. Prostaglandin E1 prevented both cytotoxic and genotoxic actions of all the three agents, where as both PGE2 and PGF2 alpha were ineffective. In fact, it was seen that both PGE2 and PGF2 alpha are genotoxic by themselves. Gamma-linolenic acid and dihomogamma-linolenic acid, the precursor of PGE1 were also as protective as that of PGE1, where as arachidonic acid, the precursor of 2 series PGs, has genotoxic actions to human lymphocytes in vitro. These results suggest that prostaglandins and their precursors can determine the susceptibility of cells to cytotoxic and genotoxic actions of chemicals and radiation. This study is particularly interesting since, it is known that some tumor cells contain excess of PGE2 and PGF2 alpha and many carcinogens can augment the synthesis of 2 series of PGs

  9. Photocatalysis-triggered ion rectification in artificial nanochannels based on chemically modified asymmetric TiO2 nanotubes.

    Science.gov (United States)

    Hu, Ziying; Zhang, Qianqian; Gao, Jun; Liu, Zhaoyue; Zhai, Jin; Jiang, Lei

    2013-04-16

    Ion rectification is one of the important characteristics of biological ion channels. Inspired by the function of biological ion channels, creation of artificial nanochannels that show analogous ion rectification characteristics has attracted a great interest recently. Herein, we demonstrate a new type of artificial solid-state nanochannel with ion rectification characteristics. The creation of artificial nanochannels includes the formation of asymmetric TiO2 nanotubes by electrochemical anodization of Ti metal, followed by chemical modification with octadecyltrimethoxysilane (OTS) molecules. The carboxylic groups are introduced onto the tip side of TiO2 nanotubes via photocatalytic decomposition of OTS molecules by TiO2 photocatalysis under ultraviolet light. When the radius of tip side of TiO2 nanotubular channels is comparable to the thickness of electric double layer, the negatively charged surface in neutral electrolyte in combination with the asymmetric pore geometry contributes to the ion rectification characteristics. Compared with previous artificial nanochannels, our new type of artificial nanochannel is more facile to fabricate and behaves as a diode that rectifies the ion transport, which also shows some other potential applications, such as sensor and separation materials.

  10. Coal-smoke pollution modifies physio-chemical characteristics of tissues during the ontogeny of Peristrophe bicalyculata

    Energy Technology Data Exchange (ETDEWEB)

    Nighat, F.; Iqbal, M. [Jamia Hamdard, New Delhi (India). Dept. of Botany

    2008-12-15

    Coal-smoke emissions of a thermal power plant affected the physio-chemical status of Peristrophe bicalyculata (Reth) Nees, as observed at the pre-flowering, flowering and post-flowering stages of plant growth. The nitrate level was raised while nitrate reductase activity, and the soluble protein content of leaf declined heavily at the polluted site during different stages of plant growth, compared to the control. The rate of photosynthesis also decreased under the pollution stress. Sugar level in root, stem and leaves increased with growing age of the plant but was always lower at the polluted site than at the reference site. In roots, the difference was marginal till flowering stage and quite conspicuous afterwards; stems showed a reverse pattern of variation. Sulphur content was higher at the polluted site in all the organs and at each stage of the plant life. The Zn and Fe concentrations were reduced in all plant parts under the pollution stress. Copper content in root was consistently low at the polluted site. In the stem and leaves, however, it was almost equal on both the sites at the pre-flowering stage but showed a wide difference during the later part of plant ontogeny.

  11. Boron Nitride Nanosheets (BNNSs) Chemically Modified by "Grafting-From" Polymerization of Poly(caprolactone) for Thermally Conductive Polymer Composites.

    Science.gov (United States)

    Lee, Jinseong; Jung, Haejong; Yu, Seunggun; Man Cho, Suk; Tiwari, Vimal K; Babu Velusamy, Dhinesh; Park, Cheolmin

    2016-07-01

    To meet the growing demand for rapid heat dissipation in electronic devices to ensure their reliable performance with a high level of safety, many polymer composites with thermally conductive but electrically insulating 2D boron nitride nanosheets (BNNSs) are being developed. Here we present an efficient way to enhance the thermal conductivity (TC) of a polymer composite by means of "grafting-from" polymerization of a poly(caprolactone) (PCL) onto BNNSs. The BNNSs, which were exfoliated from bulk BN by means of ultra-sonication, were prepared by means of radical oxidation. These oxidized BNNSs (oxi-BNNSs) were employed as initiators for subsequent ring-opening polymerization of PCL, which successfully resulted in PCL chemically grafted onto BNNSs (PCL-g-BNNSs). The excellent dispersion of PCL-g-BNNSs in common solvents allowed us to readily fabricate a polymer composite that contained PCL-g-BNNSs embedded in a PCL matrix, and the composite showed TC values that were five and nine times greater in the out-of-plane and in-plane mode, respectively, than those of pristine PCL. PMID:27283727

  12. Mechanical properties of carbon-modified silicon oxide barrier films deposited by plasma enhanced chemical vapor deposition on polymer substrates

    Energy Technology Data Exchange (ETDEWEB)

    Bieder, A. [Institute of Process Engineering, ETH Zurich, CH-8092 Zurich (Switzerland); Gondoin, V. [Institute of Process Engineering, ETH Zurich, CH-8092 Zurich (Switzerland); Leterrier, Y. [Laboratoire de Technologie des Composites et Polymeres (LTC), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Tornare, G. [Laboratoire de Technologie des Composites et Polymeres (LTC), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Rohr, Ph. Rudolf von [Institute of Process Engineering, ETH Zurich, CH-8092 Zurich (Switzerland)]. E-mail: vonrohr@ipe.mavt.ethz.ch; Manson, J.-A. E. [Laboratoire de Technologie des Composites et Polymeres (LTC), Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

    2007-05-07

    Cohesive and adhesive properties of silicon oxide barrier coatings deposited from an oxygen/hexamethyldisiloxane gas mixture by plasma enhanced chemical vapor deposition, with controlled incorporation of carbon on 12 {mu}m thick polyethylene terephtalate films were investigated. The reactor was equipped with a 2.45 GHz slot antenna plasma source and a 13.56 MHz-biased substrate holder. The two plasma sources were operated separately or in a dual mode. It was found that no or negligible internal stresses were introduced in the silicon oxide coatings as long as the increase of energy experienced by the film was compensated by the densification of the oxide. For a range of process parameters and carbon content on the changes of the crack onset strain, adhesion, and cohesion were found to be similar. Generally a high crack onset strain or good adhesion and cohesion were measured for films with an increased carbon content, although this was obtained at the expense of the gas barrier performance. Promising approaches towards high-barrier thin films with good mechanical integrity are proposed, based on coatings with a gradient in the carbon content and in the mechanical properties, on nano-composite laminates, and on organo-silane treatments.

  13. Selective adsorption of molybdenum(VI) from Mo-Re bearing effluent by chemically modified astringent persimmon.

    Science.gov (United States)

    Xiong, Ying; Wang, Haitao; Lou, Zhenning; Shan, Weijun; Xing, Zhiqiang; Deng, Guichun; Wu, Dongbei; Fang, Dawei; Biswas, Biplob Kumar

    2011-02-28

    Astringent persimmon was chemically cross-linked by formaldehyde to obtain a novel kind of adsorption gel, which was named as APF gel. The adsorption behaviors of Mo(VI) and Re(VII) along with other coexisting metals onto the APF gel were studied in the present paper. The APF gel was found to be effective for the adsorption of Mo(VI) while the gel is almost completely inert toward rhenium and calcium over the whole hydrochloric acid concentration region. The APF gel has a low affinity for iron, copper, lead, nickel, manganese and zinc ions when the concentration of HCl is higher than 1 mol/L. The gel exhibited selectivity only for Mo(VI) with a remarkably high adsorption capacity 1.05 mol/kg, and the adsorption behavior obeys the Langmuir model. According to the thermodynamic and kinetic studies, the endothermic adsorption process followed pseudo-second order kinetics. Also, its excellent adsorption characteristics for Mo(VI) were confirmed by the adsorption and elution tests using a column packed with the APF gel. The result provides a new approach for the recovery of Mo(VI) from a industrial waste effluent.

  14. Potassium selective chemically modified field effect transistors based on AlGaN/GaN two-dimensional electron gas heterostructures.

    Science.gov (United States)

    Alifragis, Y; Volosirakis, A; Chaniotakis, N A; Konstantinidis, G; Adikimenakis, A; Georgakilas, A

    2007-06-15

    We investigate the use of the AlGaN/GaN high electron mobility transistor (HEMT) as a novel transducer for the development of ion-selective chemically modified HEMT sensors (ChemHEMTs). For this, polyvinyl chloride (PVC) membrane doped with ion-selective ionophores is deposited onto the area of the gate for the chemical recognition step, while the AlGaN/GaN HEMT is used as the transducer. In particular, the use of a valinocycin doped membrane with thickness of 50 microm generates a sensor with excellent analytical characteristics for the monitoring of K(+). The K(+)-ChemHEMT has sensitivity of 52.4 mV/pK(+)in the linear range of 10(-5) to 10(-2)M, while the detection limit is in the order of 3.1 x 10(-6)M. Also, the sensor shows selectivity similar to valinomycin-based ISEs, while the signal stability over time and the measurement to measurement reproducibility are very good.

  15. People, soil and manioc interactions in the upper Amazon region

    OpenAIRE

    Peña Venegas, C.P.

    2015-01-01

    Abstract Clara Patricia Peña Venegas (2015). People, soil and manioc interactions in the upper Amazon region. PhD thesis, Wageningen University, The Netherlands, with summaries in English and Dutch, 210 pp. The presence of anthropogenic soils, or Amazonian Dark   Earths (ADE), fuels the debate about how pristine the Amazon ecosystem actually is, and about the degree to which humans affected Amazonian diversity in the past. Most upland soils of the Amazon region are very acid,...

  16. Chemodiversity of dissolved organic matter in the Amazon Basin

    Science.gov (United States)

    Gonsior, Michael; Valle, Juliana; Schmitt-Kopplin, Philippe; Hertkorn, Norbert; Bastviken, David; Luek, Jenna; Harir, Mourad; Bastos, Wanderley; Enrich-Prast, Alex

    2016-07-01

    Regions in the Amazon Basin have been associated with specific biogeochemical processes, but a detailed chemical classification of the abundant and ubiquitous dissolved organic matter (DOM), beyond specific indicator compounds and bulk measurements, has not yet been established. We sampled water from different locations in the Negro, Madeira/Jamari and Tapajós River areas to characterize the molecular DOM composition and distribution. Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) combined with excitation emission matrix (EEM) fluorescence spectroscopy and parallel factor analysis (PARAFAC) revealed a large proportion of ubiquitous DOM but also unique area-specific molecular signatures. Unique to the DOM of the Rio Negro area was the large abundance of high molecular weight, diverse hydrogen-deficient and highly oxidized molecular ions deviating from known lignin or tannin compositions, indicating substantial oxidative processing of these ultimately plant-derived polyphenols indicative of these black waters. In contrast, unique signatures in the Madeira/Jamari area were defined by presumably labile sulfur- and nitrogen-containing molecules in this white water river system. Waters from the Tapajós main stem did not show any substantial unique molecular signatures relative to those present in the Rio Madeira and Rio Negro, which implied a lower organic molecular complexity in this clear water tributary, even after mixing with the main stem of the Amazon River. Beside ubiquitous DOM at average H / C and O / C elemental ratios, a distinct and significant unique DOM pool prevailed in the black, white and clear water areas that were also highly correlated with EEM-PARAFAC components and define the frameworks for primary production and other aspects of aquatic life.

  17. Acid rain in an Amazon rainforest

    OpenAIRE

    Haines, Bruce; Jordan, Carl; Clark, Howard; Clark, Kathleen E.

    2011-01-01

    Acid rain is reported from the Amazon territory of Venezuela. The volume weighted average pHwas 4.7 for 70 storms sampled from January 1979 through February 1980. At this location,remote from point sources of industrial pollution, acid rain might result from naturalbiogeochemical processes in the rainforest, from global atmospheric pollution, or from somecombination of natural and polliition processes.DOI: 10.1111/j.1600-0889.1983.tb00011.x

  18. Health Concerns in the Amazon Region

    Centers for Disease Control (CDC) Podcasts

    2009-04-09

    Residents of the Amazon region of South America contend with a number of health threats - from mosquito-borne diseases to difficulty accessing doctors and healthcare facilities in such a vast area. This podcast helps explore some of the health issues in the region and what's being done to address them.  Created: 4/9/2009 by Emerging Infectious Diseases.   Date Released: 4/9/2009.

  19. Estimating Timber Depreciation in the Brazilian Amazon

    OpenAIRE

    Ronaldo Seroa da Motta; Claudio Ferraz

    2015-01-01

    This study applies distinct methodological forest accounting approaches, following Vincent and Hartwick (1997) lines, to estimate economic depreciation of timber exploitation in the Brazilian Amazon region. Although our results may be not definitive ones due to data availability problems, this exercise has proved to bring about issues which, though are theoretical and methodologically fully recognised, are not always revealed in other regional studies. High timber stocks, lack of well defined...

  20. Physicochemical parameters of Amazon Melipona honey

    OpenAIRE

    Ligia Bicudo de Almeida-Muradian; Adriana Hitomi Matsuda; Deborah Helena Markowicz Bastos

    2007-01-01

    Stingless bees produce a honey that is different from the Apis honey in terms of composition. There aren't enough data to establish quality control parameters for this product, mainly due to lack of research results. The aim of this work is to evaluate some physicochemical parameters that can be used for the characterization and for the quality control of the Meliponinae honey. Four different samples were collected in the Amazon region of Brazil in 2004 (Melipona compressipes manaoense bee an...

  1. Deforestation crimes and conflicts in the Amazon

    OpenAIRE

    Boekhout van Solinge, T.

    2010-01-01

    This article explores and explains deforestation of the Brazilian Amazon rainforest. It primarily takes a green criminological perspective and looks at the harm that is inflicted on many of the Amazon’s inhabitants, including indigenous populations such as ‘uncontacted’ tribes of hunters-gatherers, the oldest human societies. The green criminological perspective also implies that the definition of victimisation is being enlarged: not only (future) humans, but also non-humans can be considered...

  2. Petrobras eyes LNG project in Amazon region

    International Nuclear Information System (INIS)

    The Brazilian state oil company has proved gas reserves in the Rio Urucu area of the Amazon jungle totaling 1.84 tcf. That compares with 3.08 tcf contained in the offshore Campos basin, source of most of Brazil's oil and gas production. The environmentally sensitive Urucu region is one of the most dense, remote jungles in the world. Because of environmental concerns about pipelines in the rain forest and a government emphasis on boosting the natural gas share of Brazil's energy mix, a small liquefied natural gas project is shaping up as the best option for developing and marketing Urucu gas. The amazon campaign underscores a government initiative to boost Brazilian consumption of natural gas. In Brazil natural gas accounts for only 4% of primary energy consumption. Some years ago, the government set an official goal of boosting the gas share of the primary energy mix to 10% by 2000. The paper discusses current drilling activities, gas production and processing, the logistics of the upper Amazon, and gas markets

  3. Chagas disease and globalization of the Amazon.

    Science.gov (United States)

    Briceño-León, Roberto

    2007-01-01

    The increasing number of autochthonous cases of Chagas disease in the Amazon since the 1970s has led to fear that the disease may become a new public health problem in the region. This transformation in the disease's epidemiological pattern in the Amazon can be explained by environmental and social changes in the last 30 years. The current article draws on the sociological theory of perverse effects to explain these changes as the unwanted result of the shift from the "inward" development model prevailing until the 1970s to the "outward" model that we know as globalization, oriented by industrial forces and international trade. The current article highlights the implementation of five new patterns in agriculture, cattle-raising, mining, lumbering, and urban occupation that have generated changes in the environment and the traditional indigenous habitat and have led to migratory flows, deforestation, sedentary living, the presence of domestic animals, and changes in the habitat that facilitate colonization of human dwellings by vectors and the domestic and work-related transmission of the disease. The expansion of Chagas disease is thus a perverse effect of the globalization process in the Amazon. PMID:17308715

  4. Chemically modified carbon paste and membrane sensors for the determination of benzethonium chloride and some anionic surfactants (SLES, SDS, and LABSA): Characterization using SEM and AFM.

    Science.gov (United States)

    Issa, Yousry M; Mohamed, Sabrein H; Baset, Mohamed Abd-El

    2016-08-01

    Chemically modified carbon-paste (CMCP) and membrane- sensors based on incorporating benzothonium-tetraphenylborate (BT-TPB) were constructed for the analysis of benzethonium chloride, and some other surfactants such as sodium lauryl ether sulphate (SLES), sodium dodecyl sulphate (SDS), and linear alkylbenzene sulphonic acid (LABSA). All sensors showed good sensitivity and reverse wide linearity over a concentration range of 5.97×10(-7) to 1.00×10(-3) and 5.96×10(-7) to 3.03×10(-3)molL(-1) with limit of detection of 3.92×10(-7)and 3.40×10(-7)molL(-1) for membrane and chemically modified carbon paste sensors, respectively, with respect to benzethonium chloride (BT.Cl). They could be used over a wide pH range of 2.0-10.0. The thermal coefficients of membrane and CMCP sensors are 5.40×10(-4), 1.17×10(-4)V/°C, respectively. The sensors indicated a wide selectivity over different inorganic cations. The effect of soaking on the surface morphology of the membrane sensor was studied using EDX-SEM and AFM techniques. The response time was sensors were successfully applied for the potentiometric determination of the pure BT.Cl solution. They were also used for the determination of its pharmaceutical formulation Dermoplast(®) antibacterial spray (20% benzocaine+0.2% benzethonium chloride) with recovery values ranging from 97.54±1.70 to 101.25±1.12 and from 96.32±2.49 to 101.23±2.15%. The second goal of these sensors is the potentiometric determination of different surfactants such as SLES, SDS, and LABSA with good recovery values using BT.Cl as a titrant in their pure forms, and in samples containing one of them (shampoo, Touri(®) dishwashing liquid, and waste water). The statistical analysis of the obtained data was studied.

  5. Effect of modified atmosphere and vacuum packaging on selected chemical parameters of rainbow trout (Oncorhynchus mykiss and carp (Cyprinus carpio cuts freshness

    Directory of Open Access Journals (Sweden)

    Babić Jelena A.

    2014-01-01

    Full Text Available The purpose of food packing in modified atmosphere is to extend its sustainability by preventing both biochemical processes and growth of spoilage bacteria. Gases or their mixtures which are mostly used in the modified atmosphere food packing technology are carbon-dioxide (CO2, oxygen (O2 and nitrogen (N2. The aim of our research was to examine the influence of packaging in modified atmosphere and vacuum on the total volatile basic nitrogen (TVB-N content and pH in muscle of rainbow trout (Oncorhynchus mykiss and common carp (Cyprinus carpio, as well as to determine the most suitable gas mixtures for packing of these freshwater species. Three sample groups of trout and carp cuts were investigated. The first two groups were packaged in modified atmosphere with different gas ratios: 60%CO2+40%N2 (I group and 40%CO2+60%N2 (II group, whereas the samples from third, control group, (III group were vacuum packaged. During trials samples were stored in refrigerator at +3°C. Determination of TVB-N and pH was performed on 1st, 7th and 14th day of storage. The obtained results indicate that the investigated mixtures of gases and vacuum as well had a significant influence on the values of TVB-N in trout and carp cuts samples. The lowest increase in TVB-N was established in trout and carp cuts samples from the group I, whereas the highest increase was established in samples from group III. Statistical significant difference (p < 0,001 between the average values of TVB-N for trout (I group: 18,17 ± 0,93; II group: 20,90 ± 0,81 and III group: 36,18 ± 2,65 mg N/100 g and carp cuts (I group: 26,74 ± 1,48; II group: 30,02 ± 0,31 and III group: 35,10 ± 1,75 mg N/100 g was established on 14th day. The lowest pH value was established in samples packaged in modified atmosphere with 60% CO2 +40% N2 (I group. On 14th day of testing the obtained value was 6,15 ± 0,09 for trout and 5,94 ± 1,11 for carp samples. Increase in pH value in trout samples packed in

  6. Introduction: Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5)

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Scot T.; Artaxo, Paulo; Machado, L.A. T.; Manzi, A.; Souza, Rodrigo A.; Schumacher, Courtney; Wang, J.; Andreae, M. O.; Barbosa, Henrique; Fan, Jiwen; Fisch, G.; Goldstein, Allen H.; Guenther, A.; Jimenez, J. L.; Poschl, U.; Silva Dias, Maria Assuncao F.; Smith, J. N.; Wendisch, Manfred

    2016-04-19

    The Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) Experiment was carried out in the environs of Manaus, Brazil, in the central region of the Amazon basin during two years from 1 January 2014 through 31 December 2015. The experiment focused on the complex interactions among vegetation, atmospheric chemistry, and aerosol production on the one hand and their connections to aerosols, clouds, and precipitation on the other. The objective was to understand and quantify these linked processes, first under natural conditions to obtain a baseline and second when altered by the effects of human activities. To this end, the pollution plume from the Manaus metropolis, superimposed on the background conditions of the central Amazon basin, served as a natural laboratory. The present paper, as Introduction to the GoAmazon2014/5 Special Issue, presents the context and motivation of the GoAmazon2014/5 Experiment. The nine research sites, including the characteristics and instrumentation of each site, are presented. The sites range from time point zero (T0) upwind of the pollution, to T1 in the midst of the pollution, to T2 just downwind of the pollution, to T3 furthest downwind of the pollution (70 km). In addition to the ground sites, a low-altitude G-159 Gulfstream I (G1) observed the atmospheric boundary layer and low clouds, and a high-altitude Gulfstream G550 (HALO) operated in the free troposphere. During the two- year experiment, two Intensive Operating Periods (IOP1 and IOP2) also took place that included additional specialized research instrumentation at the ground sites as well as flights of the two aircraft. GoAmazon2014/5 IOP1 was carried out from 1 February to 31 March 2014 in the wet season. GoAmazon2014/5 IOP2 was conducted from 15 August to 15 October 2014 in the dry season. The G1 aircraft flew during both IOP1 and IOP2, and the HALO aircraft flew during IOP2. In the context of the Amazon basin, the two IOPs also correspond to the clean and

  7. Introduction: Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5)

    Science.gov (United States)

    Martin, S. T.; Artaxo, P.; Machado, L. A. T.; Manzi, A. O.; Souza, R. A. F.; Schumacher, C.; Wang, J.; Andreae, M. O.; Barbosa, H. M. J.; Fan, J.; Fisch, G.; Goldstein, A. H.; Guenther, A.; Jimenez, J. L.; Pöschl, U.; Silva Dias, M. A.; Smith, J. N.; Wendisch, M.

    2016-04-01

    The Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) Experiment was carried out in the environs of Manaus, Brazil, in the central region of the Amazon basin for 2 years from 1 January 2014 through 31 December 2015. The experiment focused on the complex interactions among vegetation, atmospheric chemistry, and aerosol production on the one hand and their connections to aerosols, clouds, and precipitation on the other. The objective was to understand and quantify these linked processes, first under natural conditions to obtain a baseline and second when altered by the effects of human activities. To this end, the pollution plume from the Manaus metropolis, superimposed on the background conditions of the central Amazon basin, served as a natural laboratory. The present paper, as the introduction to the special issue of GoAmazon2014/5, presents the context and motivation of the GoAmazon2014/5 Experiment. The nine research sites, including the characteristics and instrumentation of each site, are presented. The sites range from time point zero (T0) upwind of the pollution, to T1 in the midst of the pollution, to T2 just downwind of the pollution, to T3 furthest downwind of the pollution (70 km). In addition to the ground sites, a low-altitude G-159 Gulfstream I (G-1) observed the atmospheric boundary layer and low clouds, and a high-altitude Gulfstream G550 (HALO) operated in the free troposphere. During the 2-year experiment, two Intensive Operating Periods (IOP1 and IOP2) also took place that included additional specialized research instrumentation at the ground sites as well as flights of the two aircraft. GoAmazon2014/5 IOP1 was carried out from 1 February to 31 March 2014 in the wet season. GoAmazon2014/5 IOP2 was conducted from 15 August to 15 October 2014 in the dry season. The G-1 aircraft flew during both IOP1 and IOP2, and the HALO aircraft flew during IOP2. In the context of the Amazon basin, the two IOPs also correspond to the clean and

  8. Spectrofluorimetric determination of stoichiometry and association constants of the complexes of harmane and harmine with beta-cyclodextrin and chemically modified beta-cyclodextrins.

    Science.gov (United States)

    Martín, L; León, A; Olives, A I; Del Castillo, B; Martín, M A

    2003-06-13

    The association characteristics of the inclusion complexes of the beta-carboline alkaloids harmane and harmine with beta-cyclodextrin (beta-CD) and chemically modified beta-cyclodextrins such as hydroxypropyl-beta-cyclodextrin (HPbeta-CD), 2,3-di-O-methyl-beta-cyclodextrin (DMbeta-CD) and 2,3,6-tri-O-methyl-beta-cyclodextrin (TMbeta-CD) are described. The association constants vary from 112 for harmine/DMbeta-CD to 418 for harmane/HPbeta-CD. The magnitude of the interactions between the host and the guest molecules depends on the chemical and geometrical characteristics of the guest molecules and therefore the association constants vary for the different cyclodextrin complexes. The steric hindrance is higher in the case of harmine due to the presence of methoxy group on the beta-carboline ring. The association obtained for the harmane complexes is stronger than the one observed for harmine complexes except in the case of harmine/TMbeta-CD. Important differences in the association constants were observed depending on the experimental variable used in the calculations (absolute value of fluorescence intensity or the ratio between the fluorescence intensities corresponding to the neutral and cationic forms). When fluorescence intensity values were considered, the association constants were higher than when the ratio of the emission intensity for the cationic and neutral species was used. These differences are a consequence of the co-existence of acid-base equilibria in the ground and in excited states together with the complexation equilibria. The existence of a proton transfer reaction in the excited states of harmane or harmine implies the need for the experimental dialysis procedure for separation of the complexes from free harmane or harmine. Such methodology allows quantitative results for stoichiometry determinations to be obtained, which show the existence of both 1:1 and 1:2 beta-carboline alkaloid:CD complexes with different solubility properties.

  9. Composition and formation of organic aerosol particles in the Amazon

    Science.gov (United States)

    Pöhlker, C.; Wiedemann, K.; Sinha, B.; Shiraiwa, M.; Gunthe, S. S.; Artaxo, P.; Gilles, M. K.; Kilcoyne, A. L. D.; Moffet, R. C.; Smith, M.; Weigand, M.; Martin, S. T.; Pöschl, U.; Andreae, M. O.

    2012-04-01

    We applied scanning transmission X-ray microscopy with near edge X-ray absorption fine structure (STXM-NEXAFS) analysis to investigate the morphology and chemical composition of aerosol samples from a pristine tropical environment, the Amazon Basin. The samples were collected in the Amazonian rainforest during the rainy season and can be regarded as a natural background aerosol. The samples were found to be dominated by secondary organic aerosol (SOA) particles in the fine and primary biological aerosol particles (PBAP) in the coarse mode. Lab-generated SOA-samples from isoprene and terpene oxidation as well as pure organic compounds from spray-drying of aqueous solution were measured as reference samples. The aim of this study was to investigate the microphysical and chemical properties of a tropical background aerosol in the submicron size range and its internal mixing state. The lab-generated SOA and pure organic compounds occurred as spherical and mostly homogenous droplet-like particles, whereas the Amazonian SOA particles comprised a mixture of homogeneous droplets and droplets having internal structures due to atmospheric aging. In spite of the similar morphological appearance, the Amazon samples showed considerable differences in elemental and functional group composition. According to their NEXAFS spectra, three chemically distinct types of organic material were found and could be assigned to the following three categories: (1) particles with a pronounced carboxylic acid (COOH) peak similar to those of laboratory-generated SOA particles from terpene oxidation; (2) particles with a strong hydroxy (COH) signal similar to pure carbohydrate particles; and (3) particles with spectra resembling a mixture of the first two classes. In addition to the dominant organic component, the NEXAFS spectra revealed clearly resolved potassium (K) signals for all analyzed particles. During the rainy season and in the absence of anthropogenic influence, active biota is

  10. Green Leaf Volatile Emissions during High Temperature and Drought Stress in a Central Amazon Rainforest

    Directory of Open Access Journals (Sweden)

    Kolby J. Jardine

    2015-09-01

    Full Text Available Prolonged drought stress combined with high leaf temperatures can induce programmed leaf senescence involving lipid peroxidation, and the loss of net carbon assimilation during early stages of tree mortality. Periodic droughts are known to induce widespread tree mortality in the Amazon rainforest, but little is known about the role of lipid peroxidation during drought-induced leaf senescence. In this study, we present observations of green leaf volatile (GLV emissions during membrane peroxidation processes associated with the combined effects of high leaf temperatures and drought-induced leaf senescence from individual detached leaves and a rainforest ecosystem in the central Amazon. Temperature-dependent leaf emissions of volatile terpenoids were observed during the morning, and together with transpiration and net photosynthesis, showed a post-midday depression. This post-midday depression was associated with a stimulation of C5 and C6 GLV emissions, which continued to increase throughout the late afternoon in a temperature-independent fashion. During the 2010 drought in the Amazon Basin, which resulted in widespread tree mortality, green leaf volatile emissions (C6 GLVs were observed to build up within the forest canopy atmosphere, likely associated with high leaf temperatures and enhanced drought-induced leaf senescence processes. The results suggest that observations of GLVs in the tropical boundary layer could be used as a chemical sensor of reduced ecosystem productivity associated with drought stress.

  11. Modified DLC coatings prepared in a large-scale reactor by dual microwave/pulsed-DC plasma-activated chemical vapour deposition

    International Nuclear Information System (INIS)

    Diamond-Like Carbon (DLC) films find abundant applications as hard and protective coatings due to their excellent mechanical and tribological performances. The addition of new elements to the amorphous DLC matrix tunes the properties of this material, leading to an extension of its scope of applications. In order to scale up their production to a large plasma reactor, DLC films modified by silicon and oxygen additions have been grown in an industrial plant of 1m3 by means of pulsed-DC plasma-activated chemical vapour deposition (PACVD). The use of an additional microwave (MW) source has intensified the glow discharge, partly by electron cyclotron resonance (ECR), accelerating therefore the deposition process. Hence, acetylene, tetramethylsilane (TMS) and hexamethyldisiloxane (HMDSO) constituted the respective gas precursors for the deposition of a-C:H (DLC), a-C:H:Si and a-C:H:Si:O films by dual MW/pulsed-DC PACVD. This work presents systematic studies of the deposition rate, hardness, adhesion, abrasive wear and water contact angle aimed to optimize the technological parameters of deposition: gas pressure, relative gas flow of the monomers and input power. This study has been completed with measures of the atomic composition of the samples. Deposition rates around 1 μm/h, typical for standard processes held in the large reactor, were increased about by a factor 10 when the ionization source has been operated in ECR mode

  12. Amazon soils : a reconnaissance of the soils of the Brazilian Amazon region

    NARCIS (Netherlands)

    Sombroek, W.G.

    1966-01-01

    The study deals with soils of the Brazilian part of the Amazon basin. Most soils are Latosols, some with soft or hardened plinthite. The Latosols are characterized by a latosolic B horizon as defined in Brazil.Plinthite, its formation and morphology were extensively described. Five main types of har

  13. Preparation and rechargeability of chemical modified manganese dioxide%化学改性MnO2的制备及可充性

    Institute of Scientific and Technical Information of China (English)

    郭炳焜; 杨子运; 李新海; 徐徽; 刘丽英

    2001-01-01

    制备可充锌锰电池的关键技术之一是提高MnO2的可逆性。采用化学沉淀氧化法制备改性MnO2。研究了锰盐、掺杂物质、氧化剂、温度等对MnO2可逆性的影响。采用模拟电池及微电极技术研究MnO2的充放电性能,结合XRD、SEM检测改性MnO2的晶形和形貌。实验结果表明,当以Bi(NO3)3为掺杂物质时,制备改性MnO2的优化工艺条件是:n(Mn)/n(Bi)(摩尔比)为6~10,氧化剂用NaClO,锰盐可用Mn(NO3)2或MnSO4,25 ℃,反应时间10~15 h。所得改性MnO2呈疏松微晶粒状,是以β-MnOOH为主的β-MnOOH与β-BiOOH的混合晶相。该样品经第10次循环充放电后,其放电容量为初始放电容量的121%,10次累积放电容量是电解MnO2(EMD)的3倍。表明掺Bi3+对改善MnO2的可逆性和提高放电容量有重要作用。%Enhancing the invertibility of MnO2 was one of key technologies of preparing chargeable Zn-MnO2 battery. Chemical deposition oxidation was adopted to prepare modified MnO2 and manganic compounds, adulterants, oxidants, humidity effected to invertibility of MnO2 were studied. Charge and discharge capability of MnO2 was studied by adopting simulation cell and microelectrode. Crystal and shape of modified MnO2 were detected by XRD and SEM. The results show that the optimal technological conditions for preparing modified MnO2 by using Bi(NO3)3 as adulterant is as following: mole ratio of n(Mn)/n(Bi) is 6~10, oxidant is NaClO, manganic compound is Mn(NO3)3 or MnSO4, temperature is 25 ℃, reaction time is 10~15 h. The modified MnO2 is loosen micro-crystal powder, which is mixture of β-MnOOH with a little β-BiOOH. The powders discharge capability is 121% of initial discharge capability after the tenth charge and discharge cycle. The cumulate discharge capability of the tenth charge and discharge cycle is triple electrolyze MnO2

  14. Relationship between water transparency and physical-chemical variables in lakes of the western Amazon, Brazil=Variações entre transparência de água e variáveis físico-químicas em lagos da Amazônia Ocidental, Brasil

    Directory of Open Access Journals (Sweden)

    Giselle Vanessa Trevisan

    2012-01-01

    Full Text Available Water transparency is one of the main indicators of seasonal changes from the water level in lacustrine systems, but other environmental spatial and temporal variables can act jointly on water transparency. The diagnosis of interactions among physical-chemical variables and water transparency can be made by fitting statistical models based on multiple regression analysis. The objective of this study is to evaluate the set of limnologic variables that best predict the seasonal variation in water transparency in lakes of the western Amazon. These data were collected in both the drought and flood seasons in 78 lakes of the Mamirauá Reserve for Sustainable Development (RDSM. The delineation of the sampling followed the choice of variables, the analysis of premises imposed by the linear regression model and the validation of the model. The variables that best fitted the model were: water level, bottom temperature, conductivity, and pH for both seasons analyzed (R2 = 0.64. The resulting model suggests that the physical-chemical variables influence the re-suspension process and sedimentation of particulate material together with the seasonal variation of the water level at the lake system of RDSM.A transparência da água é um dos principais indicadores das flutuações sazonais do nível d’água em sistemas lacustres, porém outras variáveis ambientais espaço-temporais podem, conjuntamente, atuar sobre a transparência da água. O diagnóstico das interações entre variáveis físico-químicas e a transparência da água pode ser delineado pelo ajuste de modelos estatísticos fundamentados em análise de regressão múltipla. O presente estudo teve como objetivo avaliar o conjunto de variáveis limnológicas que melhor prediz a variação sazonal da transparência da água em lagos na Amazônia Ocidental. Os dados foram coletados durante os períodos de seca e cheia em 78 lagos da Reserva de Desenvolvimento Sustentável Mamirauá (RDSM. O

  15. Green Ocean Amazon 2014/15 – Scaling Amazon Carbon Water Couplings Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, Manvendra [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parket, Harrison [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Myers, Katherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rahn, Thom [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Christoffersson, B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wunch, Debra [California Inst. of Technology (CalTech), Pasadena, CA (United States); Wennberg, Paul [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2016-08-01

    Forests soak up 25% of the carbon dioxide (CO2) emitted by anthropogenic fossil energy use (10 Gt C y-1), moderating its atmospheric accumulation. How this terrestrial CO2 uptake will evolve with climate change in the 21st Century is largely unknown. Rainforests are the most active ecosystems, with the Amazon basin storing 120 Gt C as biomass and exchanging 18 Gt C y-1 of CO2 via photosynthesis and respiration and fixing carbon at 2-3 kg C m-2 y-1. Furthermore, the intense hydrologic and carbon cycles are tightly coupled in the Amazon where about half of the water is recycled by evapotranspiration and the other half imported from the ocean by Northeasterly trade winds. Climate models predict a drying in the Amazon with reduced carbon uptake while observationally guided assessments indicate sustained uptake. We set out to resolve this huge discrepancy in the size and sign of the future Amazon carbon cycle by performing the first simultaneous regional-scale high-frequency measurements of atmospheric CO2, H2O, HOD, CH4, N2O, and CO at the T3 site in Manacupuru, Brazil, as part of DOE's GoAmazon 2014/15 project. Our data will be used to inform and develop DOE's Community Land Model (CLM) on the tropical carbon-water couplings at the appropriate grid scale (10-50 km). Our measurements will also validate the CO2 data from Japan's Greenhouse gases Observing Satellite (GOSAT) and NASA's Orbiting Carbon Observatory (OCO)-2 satellite (launched in July, 2014). Our data addresses these science questions: 1. How does ecosystem heterogeneity and climate variability influence the rainforest carbon cycle? 2. How well do current tropical ecosystem models simulate the observed regional carbon cycle? 3. Does nitrogen deposition (from the Manaus, Brazil, plume) enhance rainforest carbon uptake?

  16. Proliferation of Hydroelectric Dams in the Andean Amazon and Implications for Andes-Amazon Connectivity

    Science.gov (United States)

    Finer, Matt; Jenkins, Clinton N.

    2012-01-01

    Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1) There is a critical need for further strategic regional and basin scale evaluation of dams. 2) There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3) Reconsideration of hydropower as a low-impact energy source in the Neotropics. PMID:22529979

  17. Proliferation of hydroelectric dams in the Andean Amazon and implications for Andes-Amazon connectivity.

    Directory of Open Access Journals (Sweden)

    Matt Finer

    Full Text Available Due to rising energy demands and abundant untapped potential, hydropower projects are rapidly increasing in the Neotropics. This is especially true in the wet and rugged Andean Amazon, where regional governments are prioritizing new hydroelectric dams as the centerpiece of long-term energy plans. However, the current planning for hydropower lacks adequate regional and basin-scale assessment of potential ecological impacts. This lack of strategic planning is particularly problematic given the intimate link between the Andes and Amazonian flood plain, together one of the most species rich zones on Earth. We examined the potential ecological impacts, in terms of river connectivity and forest loss, of the planned proliferation of hydroelectric dams across all Andean tributaries of the Amazon River. Considering data on the full portfolios of existing and planned dams, along with data on roads and transmission line systems, we developed a new conceptual framework to estimate the relative impacts of all planned dams. There are plans for 151 new dams greater than 2 MW over the next 20 years, more than a 300% increase. These dams would include five of the six major Andean tributaries of the Amazon. Our ecological impact analysis classified 47% of the potential new dams as high impact and just 19% as low impact. Sixty percent of the dams would cause the first major break in connectivity between protected Andean headwaters and the lowland Amazon. More than 80% would drive deforestation due to new roads, transmission lines, or inundation. We conclude with a discussion of three major policy implications of these findings. 1 There is a critical need for further strategic regional and basin scale evaluation of dams. 2 There is an urgent need for a strategic plan to maintain Andes-Amazon connectivity. 3 Reconsideration of hydropower as a low-impact energy source in the Neotropics.

  18. THE IMPACTS OF LOCAL DEMANDS, URBANIZATION AND AMAZONIAN METROPOLITAN REGIONS OVER DEFORESTATION ON BRAZILIAN AMAZON

    OpenAIRE

    Castelani, Sergio; GUILHOTO, Joaquim; Igliori, Danilo

    2013-01-01

    The paper estimates how much of the Amazon deforestation is due to the consumption of goods and services from households who live within the Amazon region itself, comparing it to deforestation driven by consumers who live outside Amazon. As the Brazilian Amazon contains 5 big Metropolitan Regions, and in order to take into account this referred urbanization process, it not only compared the effects of demand vectors from within and outside Brazilian Amazon, but also with the isolated effects ...

  19. Mapping fire events in the transition of Amazon and Cerrado biome using remote sensing

    Science.gov (United States)

    Antunes Daldegan, G.; Roberts, D. A.; Peterson, S.; Ribeiro, F.

    2015-12-01

    Abstract to AGU Fire is considered one of the determinant factors that have shaped Cerrado biome, the Brazilian Savanna, considered the most biodiverse savanna in the world. At the same time, fire has not acted a major role during the evolution of the Amazon Forest due to the strong capacity it has to resist burning. Recently, with the expansion of the agricultural activities in the central Brazil, about 49% of the Cerrado has been converted to other uses and as deforestation vector runs towards the Amazon Forest it modifies the natural moist microclimate in the edges of the forest, increasing the likelihood of wildfires. Every year these ecosystems suffer with several fire events responsible for large burned areas, causing losses of biomass, biodiversity, soil nutrients, and releasing tons of CO2 that help climate change. The occurrence of fires has a direct relationship with the climate of the central portion of the south american continent, charaterized by a two seasons regime, wet and dry, each one lasting around 6 months. In this region is located the ecotone of these two majors Brazilians ecosystems. In the Cerrado biome fire is often used to manage pasture, stimulating the regrowth of natural grasses used as pasture and also to open new areas for agriculture. There are researches showing that people have been traditionally using fire as a lower cost way to manage their lands for different purposes. In the Amazon forest the cycle of deforestation started around the 60's with incentives from the federal government to populate the region in the middle of the last century, and most recently by the progress of the commodities prices, such as soybean and sugar-cane, that has occupied vast areas of the Cerrado and is marching towards the forest. In the Amazon, fire is frequently used to further open the areas that were previously logged selectively and then converted to agricultural uses.Given the ecological importance of the Amazon Forest and Cerrado biome and the

  20. Characterization of Organic Matter under Different Pedoenvironments in the Viruá National Park, in Northern Amazon

    OpenAIRE

    José Frutuoso do Vale Júnior; Steven Nicodem; Valdinar Ferreira Melo; Sandra Catia Pereira Uchôa; Diego Lima de Sousa Cruz

    2016-01-01

    ABSTRACT Soil organic matter (SOM) fractions result from a variety of environmental processes, which affect incorporation and production rates, decomposition, alteration, and/or mineralization of organic matter. The aim of this study was to characterize SOM under the environments of rain forest, wooded campinarana (grasslands), arboreal-shrubby campinarana, grassy-woody campinarana, and pioneer plants of the Viruá National Park, in the north of the Brazilian Amazon. After chemical and physica...

  1. Use of intertidal areas by shrimps (Decapoda) in a brazilian Amazon estuary

    OpenAIRE

    HEBERT A. SAMPAIO; Jussara M. Martinelli-Lemos

    2014-01-01

    The present work investigated the occupation and the correlation of the shrimp abundance in relation to environmental variables in different habitats (mangroves, salt marshes and rocky outcrops) in an Amazon estuary. The collections were made in August and November 2009, at low syzygy tide on Areuá Beach, situated in the Extractive Reserve of Mãe Grande de Curuçá, Pará, Brazil totaling 20 pools. In each environment, we recorded the physical-chemical factors (pH, salinity, and temperature) and...

  2. Patents on periphery of the Amazon rainforest.

    Science.gov (United States)

    de Moura, Emanoel G; Araújo, José R G; Monroe, Paulo H M; de O Nascimento, Ivaneide; Aguiar, Alana C F

    2009-06-01

    In the humid tropics, on the edges of the Amazon forest, the technological challenges to establishing and maintaining productive and sustainable agricultural systems have yet to be overcome. The groups involved in agriculture in the north of Brazil still engage in the practice of slash and burn in order to prepare and fertilize the soil. This produces negative effects for the local and global environment, without the counter-effect of providing social benefits to rural communities. Whether this process continues is of fundamental importance to many countries because it means that slash and burn agriculture is advancing on the Amazon rainforest, with a negative effect on every dimension of national policy. Beyond social political problems the biggest challenge for researchers in the field of tropical agriculture is to offer technological alternatives that can sustain agriculture in soils derived from sedimentary rocks that have been subjected to a high degree of weathering. In this article patented information is also discussed. Experiments undertaken in this region recommend taking advantage of the rapid growth of plants in the tropics. We aimed at proposing a suitable alternative system for a sustainable soil management in the particular conditions of humid tropics, named as "no-till in alley cropping using tree leguminous mulch." This system offers the advantages of: bringing together, in the same space and at the same time, the processes of cultivation and the regeneration of soil fertility. PMID:20653534

  3. Copepods and fishes in the Brazilian Amazon

    Science.gov (United States)

    Thatcher, Vernon E.

    1998-06-01

    The Amazon basin comprises the largest river ecosystem in the world (7 million km 2) with annual high and low water peaks and a constant temperature near 29°C. Some 2000 fish species and 40 species of free-living copepods are known to occur in Amazonia. The free-living forms serve as food for most larval fishes and some adults, but they also transmit several parasites including representatives of the nematode family Camallanidae. About three dozen species of parasitic copepods have been described from the Brazilian Amazon. Females of Amazonian parasitic copepods are found on skin, gill filaments, gill rakers or within the nasal fossae. Parasitic copepods are found on fishes that are from a few millimeters long up to those over 2 m in length and they are usually quite host specific. All have body pigmentation in different patterns and colors (frequently blues, such as cerulean, cobalt, spectrum, smalt or campanula). It is suggested that the coloration serves to attract specific host fish. Copepods have evolved adaptations for attachment and feeding, especially in the second antennae and endopods. Examples of progenesis, phoresis and commensalism are shown. Some species produce pathology such as a tourniquet effect, hyperplasia, blood loss and anemia, and can kill fishes by limiting their respiration.

  4. Spectrometry of pasture condition and biogeochemistry in the central Amazon

    Science.gov (United States)

    Asner, Gregory P.; Townsend, Alan R.; Bustamante, Mercedes M. C.

    Regional analyses of Amazon cattle pasture biogeochemistry are difficult due to the complexity of human, edaphic, biotic and climatic factors and persistent cloud cover in satellite observations. We developed a method to estimate key biophysical properties of Amazon pastures using hyperspectral reflectance data and photon transport inverse modeling. Remote estimates of live and senescent biomass were strongly correlated with plant-available forms of soil phosphorus and calcium. These results provide a basis for monitoring pasture condition and biogeochemistry in the Amazon Basin using spaceborne hyperspectral sensors.

  5. Diversity of palm uses in the western Amazon

    DEFF Research Database (Denmark)

    Paniagua Zambrana, N.Y.; Byg, A.; Svenning, J.-C.;

    2007-01-01

    Abstract  We used palm knowledge to understand the interaction between people and the rainforests and the factors that influence this dynamic process. We interviewed 278 informants in 12 villages in the Pastaza and Madidi areas of the western Amazon basin. Together they used 38 different palm......, the great variation in the knowledge they possess, and the fact that the differences between villages is so great, are important elements to consider when developing management plans for the sustainable use of the rainforest resources in the western Amazon. Keywords  Local knowledge - Palms - Western Amazon...

  6. Observational Constraints on Terpene Oxidation with and without Anthropogenic Influence in the Amazon using Speciated Measurements from SV-TAG

    Science.gov (United States)

    Yee, L.; Isaacman, G. A.; Kreisberg, N. M.; Liu, Y.; McKinney, K. A.; de Sá, S. S.; Martin, S. T.; Alexander, M. L.; Palm, B. B.; Hu, W.; Campuzano Jost, P.; Day, D. A.; Jimenez, J. L.; Viegas, J.; Springston, S. R.; Wurm, F.; Ferreira De Brito, J.; Artaxo, P.; Manzi, A. O.; Machado, L.; Longo, K.; Oliveira, M. B.; Souza, R. A. F. D.; Hering, S. V.; Goldstein, A. H.

    2014-12-01

    Biogenic volatile organic compounds (BVOCs) from the Amazon forest represent the largest regional source of organic carbon emissions to the atmosphere. These BVOC emissions dominantly consist of volatile and semi-volatile terpenoid compounds that undergo chemical transformations in the atmosphere to form oxygenated condensable gases and secondary organic aerosol (SOA). However, the oxidation pathways of these compounds are still not well understood, and are expected to differ significantly between "pristine" conditions, as is common in Amazonia, and polluted conditions caused by emissions from growing cities. Our focus is to elucidate how anthropogenic emissions influence BVOC chemistry and BSOA formation through speciated measurements of their oxidation products. We have deployed the Semi-Volatile Thermal desorption Aerosol Gas Chromatograph (SV-TAG) at the rural T3 site located west of the urban center of Manaus, Brazil as part of the Green Ocean Amazon (GoAmazon) 2014 field campaign to measure hourly concentrations of semi-volatile BVOCs and their oxidation products during the wet and dry seasons. Primary BVOC concentrations measured by the SV-TAG include sesquiterpenes and diterpenes, which have rarely been speciated with high time-resolution. We observe sesquiterpenes to be anti-correlated with ozone, indicative of sesquiterpene oxidation playing a major role in the regional oxidant budget. The role of sesquiterpenes in atmospheric SOA formation are of interest due to their high aerosol yields and high reactivity with ozone, relative to more commonly measured BVOCs (e.g. monoterpenes). We explore relative concentrations of sesquiterpenes and monoterpenes and their roles as precursors to SOA formation by combining SV-TAG measurements with those from an additional suite of VOC and particle measurements deployed in the Amazon. We also report the first ever hourly observations of the gas-particle partitioning of speciated terpene oxidation products in the Amazon

  7. Comparison of palladium chemical modifiers for the determination of selenium in plasma by Zeeman-effect background corrected electrothermal atomic absorption spectrometry

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Jons, O.

    1997-01-01

    , It was not possible to stabilize trimethylselenonium to the same extent with this modifier, Peak shapes and appearance times of the atomization signals were equal for the four selenium species with this modifier, The addition of 20 mu g of palladium was used for the analysis of the serum reference material Seronorm...

  8. Potential groundwater contribution to Amazon evapotranspiration

    Directory of Open Access Journals (Sweden)

    Y. Fan

    2010-10-01

    Full Text Available Climate and land ecosystem models simulate a dry-season vegetation stress in the Amazon forest, but observations do not support these results, indicating adequate water supply. Proposed mechanisms include larger soil water store and deeper roots in nature and the ability of roots to move water up and down (hydraulic redistribution, both absent in the models. Here we provide a first-order assessment of the potential importance of the upward soil water flux from the groundwater driven by capillarity. We present a map of equilibrium water table depth from available observations and a groundwater model simulation constrained by these observations. We then present a map of maximum capillary flux these water table depths, combined with the fine-textured soils in the Amazon, can potentially support. The maps show that the water table beneath the Amazon can be shallow in lowlands and river valleys (<5 m in 36% and <10 m in 60% of Amazonia. These water table depths can potentially accommodate a maximum capillary flux of 2.1 mm day−1 to the land surface averaged over Amazonia, but varies from 0.6 to 3.7 mm day−1 across nine study sites.

    We note that the results presented here are based on limited observations and simple equilibrium model calculations, and as such, have important limitations and must be interpreted accordingly. The potential capillary fluxes are not indicative of their contribution to the actual evapotranspiration, and they are only an assessment of the possible rate at which this flux can occur, to illustrate the power of soil capillary force acting on a shallow water table in fine textured soils. They may over-estimate the actual flux where the surface soils remain moist. Their contribution to the actual evapotranspiration can only be assessed through fully coupled model simulation of the dynamic feedbacks between soil water and groundwater with sub-daily climate forcing. The equilibrium water table

  9. Current Characterization at the Amazon estuary

    Science.gov (United States)

    Bezerra, M. O.

    2009-04-01

    At the estuary there are several mechanisms that cause turbulence: influence of solid contours (estuary bottom and shores), speed vertical shearing (fluid inside), wind shearing stress (free surface) and surface and internal gravity waves. Turbulence intensity controls vertical distribution of estuary water mass property concentration. As flow into the estuary takes place during the transition or turbulent regimen, produced by small space and time scale movements, entrainment, turbulent scattering and advection are the processes responsible for fresh water mixing up with the sea and for local salinity variation, as well as for concentration of natural properties and man-made ones. According to this focus, we shall describe general circulation, conveyance and mixing characteristics of the Amazon low estuary waters. Amazon estuary shows unusual characteristics: it is of vast length and enormous outflow. It is extremely wide - 150 Km - and its discharge into the Atlantic amounts to 180,000 m3s-1 (Otman, 1968, Figueiredo et al, 1991), which means 18% of all water discharged by rivers into oceans; this is the largest punctual source of fresh water for oceans (Milliman and Meade, 1983). Maximum outflow is 2.5 x 105 m3s-1, and it happens at the end of May. Minimum outflow is 1.2 x 105 m3 s-1, and it takes place in November. At Amazon River, the Mixing Zone occurs where the Coastal Zone usually is. The reason for that is the extension of fresh water plume moves Northeast for over 1000 Km (Gibbs, 1970; Muller-Karger et al 1988). This is the most extensive estuarine plume ever found in the ocean. During low fluvial discharge (June-November) plume reaches 300 Km; however, on high discharge (November-May) plume reaches 500 Km. Plume already is 3 to 10 m thick and 80 to 300 Km wide (Lentz and Limeburner, 1995). From June to January plume moves towards Africa, from whence 70% of it goes east carried by North Brazil Current retroflection and 30% goes towards the Caribbean. From

  10. Remote sensing in forestry: Application to the Amazon region

    Science.gov (United States)

    Dejesusparada, N. (Principal Investigator); Tardin, A. T.; Dossantos, A.; Filho, P. H.; Shimabukuro, Y. E.

    1981-01-01

    The utilization of satellite remote sensing in forestry is reviewed with emphasis on studies performed for the Brazilian Amazon Region. Timber identification, deforestation, and pasture degradation after deforestation are discussed.

  11. Evidence of Apeu Virus Infection in Wild Monkeys, Brazilian Amazon.

    Science.gov (United States)

    Oliveira, Danilo B; Luiz, Ana Paula Moreira Franco; Fagundes, Alexandre; Pinto, Carla Amaral; Bonjardim, Cláudio A; Trindade, Giliane S; Kroon, Erna G; Abrahão, Jônatas S; Ferreira, Paulo C P

    2016-03-01

    Orthobunyaviruses are arboviruses in which at least 30 members are human pathogens. The members of group C orthobunyaviruses were first isolated in the Brazilian Amazon in 1950, since that time little information is accumulated about ecology and the medical impact of these virus groups in Brazil. Herein, we describe the evidence of Apeu virus (APEUV; an Orthobunyavirus member) infection in wild monkeys from the Brazilian Amazon forest. APEUV was detected by using a neutralizing antibody in serum and its RNA, suggesting past and acute infection of Amazonian monkeys by this virus. These results altogether represent an important contribution of orthobunyavirus ecology in the Amazon and an update about recent circulation and risk for humans with expansion of the cities to Amazon forest.

  12. Efficient generation of volatile species for cadmium analysis in seafood and rice samples by a modified chemical vapor generation system coupled with atomic fluorescence spectrometry

    International Nuclear Information System (INIS)

    Highlights: • We develop a modified chemical vapor generation method coupled with AFS for the determination of cadmium. • The response of Cd could be increased at least four-fold compared to conventional thiourea and Co(II) system. • A simple mixing sequences experiment is designed to study the reaction mechanism. • The interference of transition metal ions can be easily eliminated by adding DDTC. • The method is successfully applied in seafood samples and rice samples. - Abstract: A vapor generation procedure to determine Cd by atomic fluorescence spectrometry (AFS) has been established. Volatile species of Cd are generated by following reaction of acidified sample containing Fe(II) and L-cysteine (Cys) with sodium tetrahydroborate (NaBH4). The presence of 5 mg L−1 Fe(II) and 0.05% m/v Cys improves the efficiency of Cd vapor generation substantially about four-fold compared with conventional thiourea and Co(II) system. Three experiments with different mixing sequences and reaction times are designed to study the reaction mechanism. The results document that the stability of Cd(II)–Cys complexes is better than Cys–THB complexes (THB means NaBH4) while the Cys–THB complexes have more contribution to improve the Cd vapor generation efficiency than Cd(II)–Cys complexes. Meanwhile, the adding of Fe(II) can catalyze the Cd vapor generation. Under the optimized conditions, the detection limit of Cd is 0.012 μg L−1; relative standard deviations vary between 0.8% and 5.5% for replicate measurements of the standard solution. In the presence of 0.01% DDTC, Cu(II), Pb(II) and Zn(II) have no significant influence up to 5 mg L−1, 10 mg L−1and 10 mg L−1, respectively. The accuracy of the method is verified through analysis of the certificated reference materials and the proposed method has been applied in the determination of Cd in seafood and rice samples

  13. Efficient generation of volatile species for cadmium analysis in seafood and rice samples by a modified chemical vapor generation system coupled with atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xin-an, E-mail: 13087641@qq.com; Chi, Miao-bin, E-mail: 1161306667@qq.com; Wang, Qing-qing, E-mail: wangqq8812@163.com; Zhang, Wang-bing, E-mail: ahutwbzh@163.com

    2015-04-15

    Highlights: • We develop a modified chemical vapor generation method coupled with AFS for the determination of cadmium. • The response of Cd could be increased at least four-fold compared to conventional thiourea and Co(II) system. • A simple mixing sequences experiment is designed to study the reaction mechanism. • The interference of transition metal ions can be easily eliminated by adding DDTC. • The method is successfully applied in seafood samples and rice samples. - Abstract: A vapor generation procedure to determine Cd by atomic fluorescence spectrometry (AFS) has been established. Volatile species of Cd are generated by following reaction of acidified sample containing Fe(II) and L-cysteine (Cys) with sodium tetrahydroborate (NaBH{sub 4}). The presence of 5 mg L{sup −1} Fe(II) and 0.05% m/v Cys improves the efficiency of Cd vapor generation substantially about four-fold compared with conventional thiourea and Co(II) system. Three experiments with different mixing sequences and reaction times are designed to study the reaction mechanism. The results document that the stability of Cd(II)–Cys complexes is better than Cys–THB complexes (THB means NaBH{sub 4}) while the Cys–THB complexes have more contribution to improve the Cd vapor generation efficiency than Cd(II)–Cys complexes. Meanwhile, the adding of Fe(II) can catalyze the Cd vapor generation. Under the optimized conditions, the detection limit of Cd is 0.012 μg L{sup −1}; relative standard deviations vary between 0.8% and 5.5% for replicate measurements of the standard solution. In the presence of 0.01% DDTC, Cu(II), Pb(II) and Zn(II) have no significant influence up to 5 mg L{sup −1}, 10 mg L{sup −1}and 10 mg L{sup −1}, respectively. The accuracy of the method is verified through analysis of the certificated reference materials and the proposed method has been applied in the determination of Cd in seafood and rice samples.

  14. The impact of Amazonian deforestation on Amazon basin rainfall

    OpenAIRE

    Spracklen, DV; Garcia-Carreras, L.

    2015-01-01

    We completed a meta-analysis of regional and global climate model simulations (n=96) of the impact of Amazonian deforestation on Amazon basin rainfall. Across all simulations, mean (±1σ) change in annual mean Amazon basin rainfall was -12±11%. Variability in simulated rainfall was not explained by differences in model resolution or surface parameters. Across all simulations we find a negative linear relationship between rainfall and deforestation extent, although individual studies often simu...

  15. Reserves Protect against Deforestation Fires in the Amazon

    OpenAIRE

    J Marion Adeney; Christensen, Norman L.; Pimm, Stuart L

    2009-01-01

    BACKGROUND: Reserves are the principal means to conserve forests and biodiversity, but the question of whether reserves work is still debated. In the Amazon, fires are closely linked to deforestation, and thus can be used as a proxy for reserve effectiveness in protecting forest cover. We ask whether reserves in the Brazilian Amazon provide effective protection against deforestation and consequently fires, whether that protection is because of their location or their legal status, and whether...

  16. Declining fertility on the frontier: the Ecuadorian Amazon

    OpenAIRE

    Carr, David L.; Pan, William K. Y.; Bilsborrow, Richard E.

    2006-01-01

    This paper examines farm and household characteristics associated with a rapid fertility decline in a forest frontier of the Ecuadorian Amazon. The Amazon basin and other rainforests in the tropics are among the last frontiers in the ongoing global fertility transition. The pace of this transition along agricultural frontiers will likely have major implications for future forest transitions, rural development, and ultimately urbanization in frontier areas. The study here is based upon data fr...

  17. Sensitivity of the Amazon rainforest to convective storms

    Science.gov (United States)

    Negron Juarez, R. I.; Chambers, J. Q.; Rifai, S. W.; Urquiza Munoz, J. D.; Tello, R.; Alegria Munoz, W.; Marra, D.; Ribeiro, G.; Higuchi, N.

    2012-12-01

    The Amazon rainforest is the largest contiguous continental tropical forest in the world and is a world center of carbon storage, biodiversity, biogeochemical cycles and biogeophysical processes that affect the Earth climate system. Yet anthropogenic activities have produced changes in the forest-climate system. Consequently, an increase in rainfall in both the Western and Central Amazon and a decrease in the Eastern Amazon are expected due to these anthropogenic activities. While the projected decrease in rainfall has been discussed under the context of drought, deforestation, and fires, the effect of an increase in rainfall, and associated convective processes, on forest ecosystems has been overlooked. Across the Amazon rainforest, Western Amazonia has the highest precipitation rates, wood productivity, soil fertility, recruitment and mortality rates. Yet our field-measured tree mortality data from blowdowns that occurred in Western and Central Amazonia do not show a statistical difference in tree mortality between these regions. However, downburst velocities associated with these disturbances were calculated to be lower in Western Amazonia than in the Central Amazon. This suggests the Western Amazon is more highly sensitive to intense convective systems. This result is particularly relevant given the expected increase in rainfall in the Western and Central Amazon. The increase in rainfall is associated with more intense convective systems that in turn imply an increase in low level jet stream (LLJ) intensity east of the Andes. The presence of the LLJ is the main cause of squall lines and an increase in LLJ intensity will therefore cause increased propagation of squall lines into the Amazon basin. More frequent and active squall lines have the potential to increase the intensity and frequency of downbursts responsible for large forest blowdowns that will affect the biogeophysical feedbacks on the forest ecosystem and carbon budget.

  18. Amazon's Profit Falls, but Beats Expectations,as Company Invests

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Fpr Amazon.com, down is the new up.The Internet retailer said Tuesday that its second-quarter profit dropped by 8 percent, which might seem like bad news.But the decline was not nearly as much as Amazon, or analysts, had expected, and the profit was being sacrificed for what the company said was a good cause, new investments in technology and warehouses.Revenue continued to be strong, rising 51 percent.

  19. Cartography of affections in the Bragantine Amazon

    Directory of Open Access Journals (Sweden)

    Ênio José da Costa Brito

    2015-07-01

    Full Text Available This communication synthetically presents some elements of Jerônimo Silva e Silva’s ethnographic research. Actually it is the outlines of his doctoral thesis Cartography of affections in the encantaria: religious masters narratives from Bragantine Amazon. Silva lines out an ethnography via a cartographic flow having in mind to capture its live forces or movers. Using hermeneutics data from these narratives and living with some religious agents in situ – Pajé-Exorcista Cristino, Pajé Edvaldo, Mãe Terezinha, Mãe Lourdes, Rezadeira Luiza, Mãe Ana e Experiente Zé Maria – he unveils a plurality of relationships between people and incantation. Using some local technical concepts like corda (rope, linha (line, viração (breeze he discloses a rich social complexity in this religion of the incantation.

  20. Fog and rain in the Amazon.

    Science.gov (United States)

    Anber, Usama; Gentine, Pierre; Wang, Shuguang; Sobel, Adam H

    2015-09-15

    The diurnal and seasonal water cycles in the Amazon remain poorly simulated in general circulation models, exhibiting peak evapotranspiration in the wrong season and rain too early in the day. We show that those biases are not present in cloud-resolving simulations with parameterized large-scale circulation. The difference is attributed to the representation of the morning fog layer, and to more accurate characterization of convection and its coupling with large-scale circulation. The morning fog layer, present in the wet season but absent in the dry season, dramatically increases cloud albedo, which reduces evapotranspiration through its modulation of the surface energy budget. These results highlight the importance of the coupling between the energy and hydrological cycles and the key role of cloud albedo feedback for climates over tropical continents. PMID:26324902

  1. Bold enterprise in Amazon basin. [Gmelina arborea

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, D.

    1980-08-30

    The aim of the Jari project in Brazil is to produce food and forest products for world markets by developing a 15,000 square km tract in the Amazon basin. A pulpmill and power plant came on stream in 1979 and since then have been meeting production targets of high quality bleached pulp. The key to the success of the project has been the introduction of a fast-growing hardwood native to S.E. Asia, Gmelina arborea, which reaches a height of 30 m after 10 years, and is suitable for most wood products, pulp, sawn timber, veneer, plywood, and particleboard. It is stated that preparations are under-way to introduce Jari hardwood to European markets.

  2. Amazon River dissolved load: temporal dynamics and annual budget from the Andes to the ocean.

    Science.gov (United States)

    Moquet, Jean-Sébastien; Guyot, Jean-Loup; Crave, Alain; Viers, Jérôme; Filizola, Naziano; Martinez, Jean-Michel; Oliveira, Tereza Cristina; Sánchez, Liz Stefanny Hidalgo; Lagane, Christelle; Casimiro, Waldo Sven Lavado; Noriega, Luis; Pombosa, Rodrigo

    2016-06-01

    The aim of the present study is to estimate the export fluxes of major dissolved species at the scale of the Amazon basin, to identify the main parameters controlling their spatial distribution and to identify the role of discharge variability in the variability of the total dissolved solid (TDS) flux through the hydrological cycle. Data are compiled from the monthly hydrochemistry and daily discharge database of the "Programa Climatologico y Hidrologico de la Cuenca Amazonica de Bolivia" (PHICAB) and the HYBAM observatories from 34 stations distributed over the Amazon basin (for the 1983-1992 and 2000-2012 periods, respectively). This paper consists of a first global observation of the fluxes and temporal dynamics of each geomorphological domain of the Amazon basin. Based on mean interannual monthly flux calculations, we estimated that the Amazon basin delivered approximately 272 × 10(6) t year(-1) (263-278) of TDS during the 2003-2012 period, which represents approximately 7 % of the continental inputs to the oceans. This flux is mainly made up by HCO3, Ca and SiO2, reflecting the preferential contributions of carbonate and silicate chemical weathering to the Amazon River Basin. The main tributaries contributing to the TDS flux are the Marañon and Ucayali Rivers (approximately 50 % of the TDS production over 14 % of the Amazon basin area) due to the weathering of carbonates and evaporites drained by their Andean tributaries. An Andes-sedimentary area-shield TDS flux (and specific flux) gradient is observed throughout the basin and is first explained by the TDS concentration contrast between these domains, rather than variability in runoff. This observation highlights that, under tropical context, the weathering flux repartition is primarily controlled by the geomorphological/geological setting and confirms that sedimentary areas are currently active in terms of the production of dissolved load. The log relationships of concentration vs discharge have

  3. Dimethyl sulfide in the Amazon rain forest

    Science.gov (United States)

    Jardine, K.; Yañez-Serrano, A. M.; Williams, J.; Kunert, N.; Jardine, A.; Taylor, T.; Abrell, L.; Artaxo, P.; Guenther, A.; Hewitt, C. N.; House, E.; Florentino, A. P.; Manzi, A.; Higuchi, N.; Kesselmeier, J.; Behrendt, T.; Veres, P. R.; Derstroff, B.; Fuentes, J. D.; Martin, S. T.; Andreae, M. O.

    2015-01-01

    Surface-to-atmosphere emissions of dimethyl sulfide (DMS) may impact global climate through the formation of gaseous sulfuric acid, which can yield secondary sulfate aerosols and contribute to new particle formation. While oceans are generally considered the dominant sources of DMS, a shortage of ecosystem observations prevents an accurate analysis of terrestrial DMS sources. Using mass spectrometry, we quantified ambient DMS mixing ratios within and above a primary rainforest ecosystem in the central Amazon Basin in real-time (2010-2011) and at high vertical resolution (2013-2014). Elevated but highly variable DMS mixing ratios were observed within the canopy, showing clear evidence of a net ecosystem source to the atmosphere during both day and night in both the dry and wet seasons. Periods of high DMS mixing ratios lasting up to 8 h (up to 160 parts per trillion (ppt)) often occurred within the canopy and near the surface during many evenings and nights. Daytime gradients showed mixing ratios (up to 80 ppt) peaking near the top of the canopy as well as near the ground following a rain event. The spatial and temporal distribution of DMS suggests that ambient levels and their potential climatic impacts are dominated by local soil and plant emissions. A soil source was confirmed by measurements of DMS emission fluxes from Amazon soils as a function of temperature and soil moisture. Furthermore, light- and temperature-dependent DMS emissions were measured from seven tropical tree species. Our study has important implications for understanding terrestrial DMS sources and their role in coupled land-atmosphere climate feedbacks.

  4. Chagas disease in the Amazon Region

    Directory of Open Access Journals (Sweden)

    Hugo Marcelo Aguilar

    2007-10-01

    Full Text Available The risk that Chagas disease becomes established as a major endemic threat in Amazonia (the world's largest tropical biome, today inhabited by over 30 million people relates to a complex set of interacting biological and social determinants. These include intense immigration from endemic areas (possibly introducing parasites and vectors, extensive landscape transformation with uncontrolled deforestation, and the great diversity of wild Trypanosoma cruzi reservoir hosts and vectors (25 species in nine genera, which maintain intense sylvatic transmission cycles. Invasion of houses by adventitious vectors (with infection rates > 60% is common, and focal adaptation of native triatomines to artificial structures has been reported. Both acute (~ 500 and chronic cases of autochthonous human Chagas disease have been documented beyond doubt in the region. Continuous, low-intensity transmission seems to occur throughout the Amazon, and generates a hypoendemic pattern with seropositivity rates of ~ 1-3%. Discrete foci also exist in which transmission is more intense (e.g., in localized outbreaks probably linked to oral transmission and prevalence rates higher. Early detection-treatment of acute cases is crucial for avoiding further dispersion of endemic transmission of Chagas disease in Amazonia, and will require the involvement of malaria control and primary health care systems. Comprehensive eco-epidemiological research, including prevalence surveys or the characterization of transmission dynamics in different ecological settings, is still needed. The International Initiative for Chagas Disesae Surveillance and Prevention in the Amazon provides the framework for building up the political and scientific cooperation networks required to confront the challenge of preventing Chagas disease in Amazonia.

  5. YERSINIA PSEUDOTUBERCULOSIS, SEROGROUP O:1A, INFECTION IN TWO AMAZON PARROTS (AMAZONA AESTIVA AND AMAZONA ORATRIX) WITH HEPATIC HEMOSIDEROSIS.

    Science.gov (United States)

    Galosi, Livio; Farneti, Silvana; Rossi, Giacomo; Cork, Susan Catherine; Ferraro, Stefano; Magi, Gian Enrico; Petrini, Stefano; Valiani, Andrea; Cuteri, Vincenzo; Attili, Anna-Rita

    2015-09-01

    Necropsies were conducted on a female blue-fronted Amazon (Amazona aestiva) and a female yellow-headed Amazon (Amazona oratrix) that died after depression, ruffled feathers, diarrhea, and biliverdin in the urine. Gross and microscopic examinations revealed multifocal necrosis in the liver, spleen, lungs, kidneys, intestines, and heart caused by acute bacteremia. Yersinia pseudotuberculosis, serogroup O:1a, was isolated by culturing from the visceral lesions in the liver, intestines, and spleen. Virulence gene analysis showed the presence of the inv gene and the complete pathogenicity island: IS100, psn, yptE, irp1, irp2 ybtP-ybtQ, ybtX-ybtS, and int asnT-Int. Histopathologic findings and chemical analysis also demonstrated hepatic hemosiderosis. As has been demonstrated in other species, hemosiderosis may predispose Amazona spp. to systemic infection with Y. pseudotuberculosis after enteric disease. PMID:26352966

  6. Trace elements in aerosols from background air pollution monitoring stations in the Amazon Basin using nuclear-related techniques

    International Nuclear Information System (INIS)

    In order to study the natural release of aerosol particles by the Amazon Basin tropical rain forest, the composition and size distribution of biogenic aerosol particles were analyzed. The role of the atmospheric emissions from the Amazon Basin rain forest in the global atmosphere will be investigated. The atmosphere was studied in long-term sampling stations in three different locations. The elemental composition of aerosol particles released during biomass burning was also measured in several different ecosystems, from primary forest to Savannah. One of the main focuses was to identify and quantify important physical and chemical processes in the generation, transformation and deposition of aerosol particles. Also important was to obtain a better understanding of natural aerosol sources concerning identification, their characteristics and strength, to be able to understand the natural chemistry in the atmosphere on a global scale. 36 refs, 3 figs, 3 tabs

  7. 化学改性氧化石墨烯交联的聚酰亚胺气凝胶%Polyimide Aerogels Crosslinked with Chemically Modified Graphene Oxide

    Institute of Scientific and Technical Information of China (English)

    梁祎; 卢赟; 姚维尚; 张学同

    2015-01-01

    聚酰亚胺(PI)气凝胶是一类密度低、机械性能好、隔热性能优异的多孔材料,通常使用昂贵的化学交联剂进行交联.氧化石墨烯(GO)是近年来广受关注的用于聚合物增强的纳米功能填料.以前报道的PI/GO复合材料多是纤维或膜的形式.为了获得PI/GO复合气凝胶,本文采用化学改性氧化石墨烯(m-GO)替代1,3,5-三(4-氨基苯氧基)苯(TAB)等常规的交联剂,使之与4,4′-二氨基二苯基醚(ODA)和3,3′,4,4′-联苯四羧酸二酐(BPDA)反应,制得了m-GO交联的PI气凝胶. GO的化学改性通过其与过量ODA在水热条件下反应实现.通过扫描电子显微镜(SEM)研究了PI/m-GO气凝胶的微观结构.分别通过氮气吸脱附测试、热重分析和热线法研究了m-GO对气凝胶的孔特性、热稳定性和热导率的影响.测试结果表明,所获得的PI/m-GO气凝胶保持了高的孔隙率、热稳定性和绝热性.压缩测试结果显示,与采用1.8%(质量分数, w)的TAB进行交联的PI气凝胶相比,仅用0.6%(w)的m-GO交联所获得的气凝胶具有更高的比杨氏模量(杨氏模量/密度)、比屈服强度(屈服强度/密度)和更小的体积收缩率.%Polyimide (PI) aerogels, which are general y crosslinked using expensive chemical crosslinking agents, are novel porous materials with high strength, high heat resistance, high porosity, and low density. Graphene oxide (GO) is a functional nanofil er that has aroused wide interest in recent years. The reported PI/GO composites have mostly been in the form of fibers and films. In this study, PI/GO composite aerogels were obtained using chemical y modified graphene oxide (m-GO) as the crosslinking agent, instead of traditional ones such as 1,3,5-triaminophenoxybenzene (TAB), by reaction with 4,4′-oxydianiline (ODA) and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA). The chemical modification of GO was achieved by reacting GO with excess ODA using a hydrothermal method. The

  8. Noble metals as permanent chemical modifiers for the determination of mercury in environmental reference materials using solid sampling graphite furnace atomic absorption spectrometry and calibration against aqueous standards

    Science.gov (United States)

    da Silva, Alessandra Furtado; Welz, Bernhard; Curtius, Adilson J.

    2002-12-01

    Iridium, palladium, rhodium and ruthenium, thermally deposited on the platform, were investigated as permanent modifiers for the determination of mercury in ash, sludge, marine and river sediment reference materials, ground to a particle size of 50 μm, using solid sampling graphite furnace atomic absorption spectrometry. A total mass of 250 μg of each modifier was applied using 25 injections of 20 μl of modifier solution (500 mg l -1), and executing a temperature program for modifier conditioning after each injection. The performance of palladium was found to be most consistent, taking the characteristic mass as the major criterion, resulting in an excellent correlation between the measured integrated absorbance values and the certified mercury contents. Mercury was found to be lost in part from aqueous solutions during the drying stage in the presence of all the investigated permanent modifiers, as well as in the presence of the palladium and magnesium nitrates modifier added in solution. A loss-free determination of mercury in aqueous solutions could be reached only after the addition of potassium permanganate, which finally made possible the use of aqueous standards for the direct analysis of solid samples. A characteristic mass of 55-60 pg Hg was obtained for the solid samples, using Pd as a permanent modifier, and also in aqueous solutions after the addition of permanganate. The results obtained for mercury in ash, sludge and sediment reference materials, using direct solid sapling and calibration against aqueous standards, as well as the detection limit of 0.2 mg kg -1 were satisfactory for a routine procedure.

  9. Noble metals as permanent chemical modifiers for the determination of mercury in environmental reference materials using solid sampling graphite furnace atomic absorption spectrometry and calibration against aqueous standards

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Alessandra Furtado da; Welz, Bernhard; Curtius, Adilson J

    2002-12-02

    Iridium, palladium, rhodium and ruthenium, thermally deposited on the platform, were investigated as permanent modifiers for the determination of mercury in ash, sludge, marine and river sediment reference materials, ground to a particle size of 50 {mu}m, using solid sampling graphite furnace atomic absorption spectrometry. A total mass of 250 {mu}g of each modifier was applied using 25 injections of 20 {mu}l of modifier solution (500 mg l{sup -1}), and executing a temperature program for modifier conditioning after each injection. The performance of palladium was found to be most consistent, taking the characteristic mass as the major criterion, resulting in an excellent correlation between the measured integrated absorbance values and the certified mercury contents. Mercury was found to be lost in part from aqueous solutions during the drying stage in the presence of all the investigated permanent modifiers, as well as in the presence of the palladium and magnesium nitrates modifier added in solution. A loss-free determination of mercury in aqueous solutions could be reached only after the addition of potassium permanganate, which finally made possible the use of aqueous standards for the direct analysis of solid samples. A characteristic mass of 55-60 pg Hg was obtained for the solid samples, using Pd as a permanent modifier, and also in aqueous solutions after the addition of permanganate. The results obtained for mercury in ash, sludge and sediment reference materials, using direct solid sapling and calibration against aqueous standards, as well as the detection limit of 0.2 mg kg{sup -1} were satisfactory for a routine procedure.

  10. Trace elements and radionuclides in the Connecticut River and Amazon River estuary

    International Nuclear Information System (INIS)

    The Connecticut River, its estuary, and the Amazon River estuary were studied to elucidate some of the processes which control river water chemistry and the flux of elements to the sea. The approach taken was to identify inputs to the Connecticut River and to investigate geochemical processes which modify the dissolved load. The form and quantity of nuclides which are in turn supplied to the estuary are altered by processes unique to that transition zone to the ocean. The Connecticut River estuary was sampled on a seasonal basis to investigate the role of the estuary in controlling the flux of elements to the sea. The knowledge gained from the Connecticut River study was applied to the quantitatively more significant Amazon River estuary. There a variety of samples were analyzed to understand the processes controlling the single greatest flux of elements to the Atlantic Ocean. The results indicate that estimates of the total flux of nuclides to the oceans can best be calculated based on groundwater inputs. Unless significant repositories for nuclides exist in the river-estuarine system, the groundwater flux of dissolved nuclides is that which will eventually be delivered to the ocean despite the reactions which were shown to occur in both rivers and estuaries. 153 references, 63 figures, 28 tables

  11. 77 FR 14852 - Advanced Growing Systems, Inc., Advantage Capital Development Corp., Amazon Biotech, Inc...

    Science.gov (United States)

    2012-03-13

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Advanced Growing Systems, Inc., Advantage Capital Development Corp., Amazon Biotech, Inc., Andover... of current and accurate information concerning the securities of Amazon ] Biotech, Inc. because...

  12. Aircraft measurements of aerosol properties during GoAmazon - G1 and HALO inter-comparison

    Science.gov (United States)

    Mei, F.; Cecchini, M. A.; Wang, J.; Tomlinson, J. M.; Comstock, J. M.; Hubbe, J. M.; Pekour, M. S.; Machado, L.; Wendisch, M.; Longo, K.; Martin, S. T.; Schmid, B.; Weinzierl, B.; Krüger, M. L.; Zöger, M.

    2015-12-01

    Currently, the indirect effects of atmospheric aerosols remain the most uncertain components in forcing of climate change over the industrial period (IPCC, 2013). This large uncertainty is partially a result of our incomplete understanding of the ability of particles to form cloud droplets under atmospherically relevant supersaturations. One objective of the US Department of Energy (DOE) Green Ocean Amazon Project (GoAmazon2014/5) is to understand the influence of the emission from Manaus, a tropical megacity, on aerosol size, concentration, and chemical composition, and their impact on cloud condensation nuclei (CCN) spectrum. The GoAmazon2014/5 study was an international campaign with the collaboration efforts from US, Brazil and Germany. During the intensive operation period, in the dry season (Sep. 1st - Oct. 10th, 2014), aerosol concentration, size distributions, and CCN spectra, both under pristine conditions and inside the Manaus plume, were characterized in-situ from the DOE Gulfstream-1 (G-1) research aircraft and German HALO aircraft during 4 coordinated flights on Sep. 9th, Sep. 16th, Sep 21st and Oct. 1st, 2014. During those four flights, aerosol number concentrations and CCN concentrations at two supersaturations (0.25% and 0.5%) were measured by condensation particle counters (CPCs) and a DMT dual column CCN counter onboard both G-1 and HALO. Aerosol size distribution was also measured by a Fast Integrated Mobility Spectrometer (FIMS) aboard the G-1 and is compared with the size distribution from Ultra High Sensitivity Aerosol Spectrometer - Airborne (UHSAS-A, DMT), which were deployed both on the G-1 and the HALO. Good agreement between the aerosol properties measured from the two aircraft has been achieved. The vertical profiles of aerosol size distribution and CCN spectrum will be discussed.

  13. The ceramic artifacts in archaeological black earth (terra preta) from lower Amazon region, Brazil: mineralogy Artefatos cerâmicos em sítios arqueológios com terra preta na região do baixo Amazonas, Brasil: mineralogia

    OpenAIRE

    Marcondes Lima da Costa; Dirse Clara Kern; Alice Helena Eleotério Pinto; Jorge Raimundo da Trindade Souza

    2004-01-01

    Several archaeological black earth (ABE) sites occur in the Amazon region. They contain fragments of ceramic artifacts, which are very important for the archaeological purpose. In order to improve the archaeological study in the region we carried out a detailed mineralogical and chemical study of the fragments of ceramic artifacts found in the two ABE sites of Cachoeira-Porteira, in the Lower Amazon Region. Their ceramics comprise the following tempers: cauixi, cariapé, sand, sand +feldspars,...

  14. Programming Amazon Web Services S3, EC2, SQS, FPS, and SimpleDB

    CERN Document Server

    Murty, James

    2009-01-01

    With this book, you'll learn how companies can take advantage of Amazon Web Services (AWS) to rent" computing power, data storage and bandwidth on Amazon's vast network infrastructure. Programming Amazon Web Services gives developers the background and technical detail they need for using Amazon's subscription-based Simple Storage Service (S3), Elastic Compute Cloud (EC2), Simple Queue Service (SQS), Flexible Payments Service (FPS), and SimpleDB to build web-scale business applications. "

  15. Regional nitrous oxide flux in Amazon basin

    International Nuclear Information System (INIS)

    Nitrous oxide (N2O) is the third most important anthropogenic greenhouse gas. Globally, the main sources of N2O are nitrification and denitrification in soils. About two thirds of the soil emissions occur in the tropics and approximately 20% originate in wet rain forest ecosystems, like the Amazon forest. The work presented here involves aircraft vertical profiles of N2O from the surface to 4 km over two sites in the Eastern and Central Amazon: Tapajos National Forest (2000-2009) and Cuieiras Biologic Reserve (2004-2007), and the estimation of N2O fluxes for regions upwind of these sites using two methods: Column Integration Technique and Inversion Model - FLEXPART. To our knowledge, these regional scale N2O measurements in Amazonia are unique and represent a new approach to looking regional scale emissions. For the both methods, the fluxes upwind of Cuieiras Biologic Reserve exhibited little seasonality, and the annual mean was 1.9 ±1.6 mgN2Om-2day-1 for the Column Integration Technique and 2.3±0.9 mgN2Om-2day-1 for Inversion Model - FLEXPART. For fluxes upwind of Tapajos Nacional Forest, the Inversion Model - FLEXPART presented about half (0.9±1.7 mgN2Om-2day-1) of the Column Integration Technique (2.0±1.1 mgN2Om-2day-1) for the same period (2004-2008). One reason could be because the inversion model does not consider anthropic activities, once it had a good representation for less impacted area. Both regions presented similar emission during wet season. By Column Integration Technique, fluxes upwind Tapajos Nacional Forest were similar for dry and wet seasons. The dry season N2O fluxes exhibit significant correlations with CO fluxes, indicating a larger than expected source of N2O from biomass burning. The average CO:N2O ratio for all 38 profiles sampled during the dry season was 82±69 mol CO:molN2O and suggests a larger biomass burning contribution to the global N2O budget than previously reported. (author)

  16. Carbon Emissions from Deforestation in the Brazilian Amazon Region

    Science.gov (United States)

    Potter, C.; Klooster, S.; Genovese, V.

    2009-01-01

    A simulation model based on satellite observations of monthly vegetation greenness from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000-2002. The NASA-CASA (Carnegie Ames Stanford Approach) model estimates of annual forest production were used for the first time as the basis to generate a prediction for the standing pool of carbon in above-ground biomass (AGB; gC/sq m) for forested areas of the Brazilian Amazon region. Plot-level measurements of the residence time of carbon in wood in Amazon forest from Malhi et al. (2006) were interpolated by inverse distance weighting algorithms and used with CASA to generate a new regional map of AGB. Data from the Brazilian PRODES (Estimativa do Desflorestamento da Amazonia) project were used to map deforested areas. Results show that net primary production (NPP) sinks for carbon varied between 4.25 Pg C/yr (1 Pg=10(exp 15)g) and 4.34 Pg C for the region and were highest across the eastern and northern Amazon areas, whereas deforestation sources of CO2 flux from decomposition of residual woody debris were higher and less seasonal in the central Amazon than in the eastern and southern areas. Increased woody debris from past deforestation events was predicted to alter the net ecosystem carbon balance of the Amazon region to generate annual CO2 source fluxes at least two times higher than previously predicted by CASA modeling studies. Variations in climate, land cover, and forest burning were predicted to release carbon at rates of 0.5 to 1 Pg C/yr from the Brazilian Amazon. When direct deforestation emissions of CO2 from forest burning of between 0.2 and 0.6 Pg C/yr in the Legal Amazon are overlooked in regional budgets, the year-to-year variations in this net biome flux may appear to be large, whereas our model results implies net biome fluxes had actually been relatively consistent from

  17. Methane emissions from floodplain trees of the Amazon basin

    Science.gov (United States)

    Pangala, Sunitha; Bastviken, David; Enrich-Prast, Alex; Gauci, Vincent

    2016-04-01

    Wetlands are the largest source of methane to the atmosphere, but emission estimates are highly uncertain leading to large discrepancies between emission inventories and much larger estimates of the Amazon methane source derived at larger scales. We examined methane emissions from all emission pathways including aquatic surfaces, emergent soils and herbaceous vegetation and more than 2000 trees from 13 locations across the central Amazon floodplain in 2014. Our data are the first measurements of stem emission from emergent portions of inundated trees in the Amazon and they demonstrate that regionally, tree stems are the dominant means of emissions for soil produced methane to the atmosphere. Emissions via the range of egress pathways varied substantially between sample locations and water-table exerted some control over emissions from ~2m below the soil surface upto 0.5-1m of inundation. Higher water (upto ~10m of inundation) exerted no further control over emissions. Applying our measurements to models of whole tree emission and scaling to the entire Amazon lowland basin demonstrates the significant contribution of trees to regional emissions that can close the Amazon basin methane budget.

  18. Spatiotemporal variability of methane over the Amazon from satellite observations

    Science.gov (United States)

    Ribeiro, Igor Oliveira; de Souza, Rodrigo Augusto Ferreira; Andreoli, Rita Valéria; Kayano, Mary Toshie; Costa, Patrícia dos Santos

    2016-07-01

    The spatiotemporal variability of the greenhouse gas methane (CH4) in the atmosphere over the Amazon is studied using data from the space-borne measurements of the Atmospheric Infrared Sounder on board NASA's AQUA satellite for the period 2003-12. The results show a pronounced variability of this gas over the Amazon Basin lowlands region, where wetland areas occur. CH4 has a well-defined seasonal behavior, with a progressive increase of its concentration during the dry season, followed by a decrease during the wet season. Concerning this variability, the present study indicates the important role of ENSO in modulating the variability of CH4 emissions over the northern Amazon, where this association seems to be mostly linked to changes in flooded areas in response to ENSO-related precipitation changes. In this region, a CH4 decrease (increase) is due to the El Niño-related (La Niña-related) dryness (wetness). On the other hand, an increase (decrease) in the biomass burning over the southeastern Amazon during very dry (wet) years explains the increase (decrease) in CH4 emissions in this region. The present analysis identifies the two main areas of the Amazon, its northern and southeastern sectors, with remarkable interannual variations of CH4. This result might be useful for future monitoring of the variations in the concentration of CH4, the second-most important greenhouse gas, in this area.

  19. The impact of Amazonian deforestation on Amazon basin rainfall

    Science.gov (United States)

    Spracklen, D. V.; Garcia-Carreras, L.

    2015-11-01

    We completed a meta-analysis of regional and global climate model simulations (n = 96) of the impact of Amazonian deforestation on Amazon basin rainfall. Across all simulations, mean (±1σ) change in annual mean Amazon basin rainfall was -12 ± 11%. Variability in simulated rainfall was not explained by differences in model resolution or surface parameters. Across all simulations we find a negative linear relationship between rainfall and deforestation extent, although individual studies often simulate a nonlinear response. Using the linear relationship, we estimate that deforestation in 2010 has reduced annual mean rainfall across the Amazon basin by 1.8 ± 0.3%, less than the interannual variability in observed rainfall. This may explain why a reduction in Amazon rainfall has not consistently been observed. We estimate that business-as-usual deforestation (based on deforestation rates prior to 2004) would lead to an 8.1 ± 1.4% reduction in annual mean Amazon basin rainfall by 2050, greater than natural variability.

  20. Green Ocean Amazon (GoAmazon) 2014/15. Semi-Volatile Thermal Desorption Aerosol Gas Chromatograph (SVTAG) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, A. H. [Univ. of California, Berkeley, CA (United States); Yee, L. D. [Univ. of California, Berkeley, CA (United States); Issacman-VanWertz, G. [Univ. of California, Berkeley, CA (United States); Wernis, R. A. [Univ. of California, Berkeley, CA (United States)

    2016-03-01

    In areas where biogenic emissions are oxidized in the presence of anthropogenic pollutants such as SO2, NOx, and black carbon, it has become increasingly apparent that secondary organic aerosol (SOA) formation from biogenic volatile organic compounds (VOCs) is substantially enhanced. Research is urgently needed to elucidate fundamental processes of natural and anthropogenically influenced VOC oxidation and the contribution of these processes to SOA formation. GoAmazon 2014/15 afforded study of the chemical transformations in the region downwind of Manaus, Brazil, where local biogenic VOC emissions are high, and their chemical oxidation can be studied both inside and outside of the urban plume to differentiate the role of anthropogenic influence on secondary aerosol formation during oxidation of these natural VOC emissions. To understand the connection between primary biogenic VOC emissions and their secondary products that form aerosols, we made time-resolved molecular level measurements by deploying a Semi-Volatile Thermal Desorption Aerosol Gas Chromatograph (SV-TAG) and a sequential filter sampler during two intensive operational periods (IOPs) of the GoAmazon 2014/15 field campaign. The SV-TAG measured semi-volatile organic compounds in both the gas and particle phases and the sequential filter sampler collected aerosols on quartz fiber filters in four-hour increments used for offline analysis. SV-TAG employed novel online derivatization that provided chemical speciation of highly oxygenated or functionalized compounds that comprise a substantial fraction of secondary organic aerosols, yet are poorly characterized. It also provided partitioning of these compounds between the vapor and particle phases at sufficient time resolution to define the importance of competing atmospheric processes. These measurements were supported by offline analysis of the filters using two-dimensional gas chromatography (GC x GC) with high-resolution time-of-flight mass spectrometry

  1. Modified cyanobacteria

    Science.gov (United States)

    Vermaas, Willem F J.

    2014-06-17

    Disclosed is a modified photoautotrophic bacterium comprising genes of interest that are modified in terms of their expression and/or coding region sequence, wherein modification of the genes of interest increases production of a desired product in the bacterium relative to the amount of the desired product production in a photoautotrophic bacterium that is not modified with respect to the genes of interest.

  2. Physicochemical parameters of Amazon Melipona honey

    Directory of Open Access Journals (Sweden)

    Ligia Bicudo de Almeida-Muradian

    2007-06-01

    Full Text Available Stingless bees produce a honey that is different from the Apis honey in terms of composition. There aren't enough data to establish quality control parameters for this product, mainly due to lack of research results. The aim of this work is to evaluate some physicochemical parameters that can be used for the characterization and for the quality control of the Meliponinae honey. Four different samples were collected in the Amazon region of Brazil in 2004 (Melipona compressipes manaoense bee and Melipona seminigra merribae bee. Honey analyses were performed as described by the official methods. The mean results were: moisture (30.13%, pH (3.65, acidity (24.57 mEq/kg, water activity (0.75, fructose (31.91%, glucose (29.30% and sucrose (0.19%. These results reinforce the need for a specific regulation for stingless bee honey. This will only be feasible when enough data is available to establish upper and lower limits for the physicochemical parameters used for quality control.

  3. Rickettsial Disease in the Peruvian Amazon Basin.

    Science.gov (United States)

    Kocher, Claudine; Morrison, Amy C; Leguia, Mariana; Loyola, Steev; Castillo, Roger M; Galvez, Hugo A; Astete, Helvio; Flores-Mendoza, Carmen; Ampuero, Julia S; Bausch, Daniel G; Halsey, Eric S; Cespedes, Manuel; Zevallos, Karine; Jiang, Ju; Richards, Allen L

    2016-07-01

    Using a large, passive, clinic-based surveillance program in Iquitos, Peru, we characterized the prevalence of rickettsial infections among undifferentiated febrile cases and obtained evidence of pathogen transmission in potential domestic reservoir contacts and their ectoparasites. Blood specimens from humans and animals were assayed for spotted fever group rickettsiae (SFGR) and typhus group rickettsiae (TGR) by ELISA and/or PCR; ectoparasites were screened by PCR. Logistic regression was used to determine associations between patient history, demographic characteristics of participants and symptoms, clinical findings and outcome of rickettsial infection. Of the 2,054 enrolled participants, almost 2% showed evidence of seroconversion or a 4-fold rise in antibody titers specific for rickettsiae between acute and convalescent blood samples. Of 190 fleas (Ctenocephalides felis) and 60 ticks (Rhipicephalus sanguineus) tested, 185 (97.4%) and 3 (5%), respectively, were positive for Rickettsia spp. Candidatus Rickettsia asemboensis was identified in 100% and 33% of the fleas and ticks tested, respectively. Collectively, our serologic data indicates that human pathogenic SFGR are present in the Peruvian Amazon and pose a significant risk of infection to individuals exposed to wild, domestic and peri-domestic animals and their ectoparasites.

  4. Rickettsial Disease in the Peruvian Amazon Basin.

    Science.gov (United States)

    Kocher, Claudine; Morrison, Amy C; Leguia, Mariana; Loyola, Steev; Castillo, Roger M; Galvez, Hugo A; Astete, Helvio; Flores-Mendoza, Carmen; Ampuero, Julia S; Bausch, Daniel G; Halsey, Eric S; Cespedes, Manuel; Zevallos, Karine; Jiang, Ju; Richards, Allen L

    2016-07-01

    Using a large, passive, clinic-based surveillance program in Iquitos, Peru, we characterized the prevalence of rickettsial infections among undifferentiated febrile cases and obtained evidence of pathogen transmission in potential domestic reservoir contacts and their ectoparasites. Blood specimens from humans and animals were assayed for spotted fever group rickettsiae (SFGR) and typhus group rickettsiae (TGR) by ELISA and/or PCR; ectoparasites were screened by PCR. Logistic regression was used to determine associations between patient history, demographic characteristics of participants and symptoms, clinical findings and outcome of rickettsial infection. Of the 2,054 enrolled participants, almost 2% showed evidence of seroconversion or a 4-fold rise in antibody titers specific for rickettsiae between acute and convalescent blood samples. Of 190 fleas (Ctenocephalides felis) and 60 ticks (Rhipicephalus sanguineus) tested, 185 (97.4%) and 3 (5%), respectively, were positive for Rickettsia spp. Candidatus Rickettsia asemboensis was identified in 100% and 33% of the fleas and ticks tested, respectively. Collectively, our serologic data indicates that human pathogenic SFGR are present in the Peruvian Amazon and pose a significant risk of infection to individuals exposed to wild, domestic and peri-domestic animals and their ectoparasites. PMID:27416029

  5. Rickettsial Disease in the Peruvian Amazon Basin

    Science.gov (United States)

    Kocher, Claudine; Morrison, Amy C.; Leguia, Mariana; Loyola, Steev; Castillo, Roger M.; Galvez, Hugo A.; Astete, Helvio; Flores-Mendoza, Carmen; Ampuero, Julia S.; Bausch, Daniel G.; Halsey, Eric S.; Cespedes, Manuel; Zevallos, Karine; Jiang, Ju; Richards, Allen L.

    2016-01-01

    Using a large, passive, clinic-based surveillance program in Iquitos, Peru, we characterized the prevalence of rickettsial infections among undifferentiated febrile cases and obtained evidence of pathogen transmission in potential domestic reservoir contacts and their ectoparasites. Blood specimens from humans and animals were assayed for spotted fever group rickettsiae (SFGR) and typhus group rickettsiae (TGR) by ELISA and/or PCR; ectoparasites were screened by PCR. Logistic regression was used to determine associations between patient history, demographic characteristics of participants and symptoms, clinical findings and outcome of rickettsial infection. Of the 2,054 enrolled participants, almost 2% showed evidence of seroconversion or a 4-fold rise in antibody titers specific for rickettsiae between acute and convalescent blood samples. Of 190 fleas (Ctenocephalides felis) and 60 ticks (Rhipicephalus sanguineus) tested, 185 (97.4%) and 3 (5%), respectively, were positive for Rickettsia spp. Candidatus Rickettsia asemboensis was identified in 100% and 33% of the fleas and ticks tested, respectively. Collectively, our serologic data indicates that human pathogenic SFGR are present in the Peruvian Amazon and pose a significant risk of infection to individuals exposed to wild, domestic and peri-domestic animals and their ectoparasites. PMID:27416029

  6. Amazonian dark Earth and plant species from the Amazon region contribute to shape rhizosphere bacterial communities.

    Science.gov (United States)

    Barbosa Lima, Amanda; Cannavan, Fabiana Souza; Navarrete, Acacio Aparecido; Teixeira, Wenceslau Geraldes; Kuramae, Eiko Eurya; Tsai, Siu Mui

    2015-05-01

    Amazonian Dark Earths (ADE) or Terra Preta de Índio formed in the past by pre-Columbian populations are highly sustained fertile soils supported by microbial communities that differ from those extant in adjacent soils. These soils are found in the Amazon region and are considered as a model soil when compared to the surrounding and background soils. The aim of this study was to assess the effects of ADE and its surrounding soil on the rhizosphere bacterial communities of two leguminous plant species that frequently occur in the Amazon region in forest sites (Mimosa debilis) and open areas (Senna alata). Bacterial community structure was evaluated using terminal restriction fragment length polymorphism (T-RFLP) and bacterial community composition by V4 16S rRNA gene region pyrosequencing. T-RFLP analysis showed effect of soil types and plant species on rhizosphere bacterial community structure. Differential abundance of bacterial phyla, such as Acidobacteria, Actinobacteria, Verrucomicrobia, and Firmicutes, revealed that soil type contributes to shape the bacterial communities. Furthermore, bacterial phyla such as Firmicutes and Nitrospira were mostly influenced by plant species. Plant roots influenced several soil chemical properties, especially when plants were grown in ADE. These results showed that differences observed in rhizosphere bacterial community structure and composition can be influenced by plant species and soil fertility due to variation in soil attributes. PMID:25103911

  7. GoAmazon2014/15. Oxidation Flow Reactor Final Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, J. L. [Univ. of Colorado, Boulder, CO (United States); Day, D. A. [Univ. of Colorado, Boulder, CO (United States); Hu, W. [Univ. of Colorado, Boulder, CO (United States); Palm, B. B. [Univ. of Colorado, Boulder, CO (United States); Campuzano-Jost, P. [Univ. of Colorado, Boulder, CO (United States)

    2016-03-01

    The primary goal of the Green Ocean Amazon (GoAmazon2014/5) field campaign was to measure and mechanistically understand the formation of particle number and mass in a region affected by large tropical rainforest biogenic emissions and sometimes anthropogenic influence from a large urban center. As part of the two intensive operational periods (IOPs) and in collaboration with Pacific Northwest National Laboratory (PNNL) and Harvard, the Jimenez Group proposed to deploy a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS), Thermal Denuder (TD), Scanning Mobility Particle Size (SMPS), two oxidation flow reactors (OFR; including supporting O3, CO/CO2/CH4, RH analyzers), and a high volume filter sampler (MCV) for the measurement of gas and aerosol chemical, physicochemical, and volatility properties. The two IOPs were conducted during the wet season (February to March, 2014) and dry season (August to October, 2014). This proposal was part of a collaborative proposal involving other university and government laboratories.

  8. Observations and Modeling of the Green Ocean Amazon (GOAMAZON). Particulate Matter and Gases Final Campaign Summary

    Energy Technology Data Exchange (ETDEWEB)

    Godoi, R. H.M. [Atmospheric Radiation Measurement (ARM), Climate Research Facility , Washington, DC (United States); Federal Univ. of Parana (Brazil); Barbosa, C. G.G. [Atmospheric Radiation Measurement (ARM), Climate Research Facility , Washington, DC (United States); Federal Univ. of Parana (Brazil); Kurzlop, P. [Atmospheric Radiation Measurement (ARM), Climate Research Facility , Washington, DC (United States); Souza, R. A.F. [Atmospheric Radiation Measurement (ARM), Climate Research Facility , Washington, DC (United States); Amazonas State Univ. (Brazil); Paralovo, S. L. [Atmospheric Radiation Measurement (ARM), Climate Research Facility , Washington, DC (United States); Federal Univ. of Parana (Brazil); Carneiro, I. P. S. [Atmospheric Radiation Measurement (ARM), Climate Research Facility , Washington, DC (United States)

    2016-03-01

    Because of their proven adverse effects on human health and vegetation, and also considering their influence over the local and regional climate, inhalable fine particles (PM2.5) and NO2, SO2, and O3 have been collected at the ARM site located in Manacapuru, Amazon, Brazil, as a part of the GoAmazon 2014/5 project. PM2.5 samples were analyzed through gravimetry, black carbon transmittance, elemental composition by energy dispersive x-ray fluorescence, and ionic concentration (cations) by ion chromatography. NO2 and SO2 samples were analyzed by ion chromatography, whereas O3 samples were analyzed through ultraviolet-vis spectrophotometry. Sampling of both particulate and gaseous pollutants took place during the two intensive operation periods (IOP1 from February to March 2014, and IOP2 from August to October 2014). Results are interpreted both separately and as a whole with the specific goal of identifying compounds that could affect the population’s health and/or could act as cloud condensation nuclei. Chemical analysis supports the elucidation of the possible origins, transport mechanisms, health effects, and main effects of the assessed pollutants in those environments

  9. Radiation and chemical interactions producing cellular and subcellular damage and their repair. Coordinated programme on improvement in radiotherapy of cancer using modifiers of radiosensitivity of cells

    International Nuclear Information System (INIS)

    As a result of biochemical studies on the DNA repair of damages induced by ionizing radiation as well as on the radiosensitization with chemicals containing halogen atoms, it was suggested that inhibition of the post-irradiation repair by chemical factors may be useful in improving the radiotherapy. It was possbile to prepare an in vitro repair system in combination with transforming DNA of Bacillus subtilis as well as human placenta extracts; it was shown that certain radiosensitizers worked actually as repair inhibitors in this in vitro system

  10. Assessing the Amazon Cloud Suitability for CLARREO's Computational Needs

    Science.gov (United States)

    Goldin, Daniel; Vakhnin, Andrei A.; Currey, Jon C.

    2015-01-01

    In this document we compare the performance of the Amazon Web Services (AWS), also known as Amazon Cloud, with the CLARREO (Climate Absolute Radiance and Refractivity Observatory) cluster and assess its suitability for computational needs of the CLARREO mission. A benchmark executable to process one month and one year of PARASOL (Polarization and Anistropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar) data was used. With the optimal AWS configuration, adequate data-processing times, comparable to the CLARREO cluster, were found. The assessment of alternatives to the CLARREO cluster continues and several options, such as a NASA-based cluster, are being considered.

  11. Beginning Amazon Web Services with Node.js

    CERN Document Server

    Shackelford, Adam

    2015-01-01

    Beginning Amazon Web Services with Node.js teaches any novice Node.js developer to configure, deploy, and maintain scalable small to large scale Node.js applications in Amazon Web Services. Hosting a Node.js application in a production environment usually means turning to PaaS hosting, but this approach brings problems. Deploying Node.js directly to AWS solves the problems you encounter in these situations, enabling you to cut out the middle man. You will begin with a basic RESTful web service in Node.js, using the popular Express.js framework, pre-built and ready to run in your local env

  12. Osteoma in a blue-fronted Amazon parrot (Amazona aestiva).

    Science.gov (United States)

    Cardoso, João Felipe Rito; Levy, Marcelo Guilherme Bezerra; Liparisi, Flavia; Romão, Mario Antonio Pinto

    2013-09-01

    Osteoma is an uncommon bone formation documented in avian species and other animals. A blue-fronted Amazon parrot (Amazona aestiva) with clinical respiratory symptoms was examined because of a hard mass present on the left nostril. Radiographs suggested a bone tumor, and the mass was surgically excised. Histopathologic examination revealed features of an osteoma. To our knowledge, this is the first description of an osteoma in a blue-fronted Amazon parrot. Osteoma should be considered as a differential diagnosis in birds with respiratory distress and swelling of the nostril.

  13. Amazon Forests’ Response to Droughts: A Perspective from the MAIAC Product

    Directory of Open Access Journals (Sweden)

    Jian Bi

    2016-04-01

    Full Text Available Amazon forests experienced two severe droughts at the beginning of the 21st century: one in 2005 and the other in 2010. How Amazon forests responded to these droughts is critical for the future of the Earth’s climate system. It is only possible to assess Amazon forests’ response to the droughts in large areal extent through satellite remote sensing. Here, we used the Multi-Angle Implementation of Atmospheric Correction (MAIAC Moderate Resolution Imaging Spectroradiometer (MODIS vegetation index (VI data to assess Amazon forests’ response to droughts, and compared the results with those from the standard (Collection 5 and Collection 6 MODIS VI data. Overall, the MAIAC data reveal more realistic Amazon forests inter-annual greenness dynamics than the standard MODIS data. Our results from the MAIAC data suggest that: (1 the droughts decreased the greenness (i.e., photosynthetic activity of Amazon forests; (2 the Amazon wet season precipitation reduction induced by El Niño events could also lead to reduced photosynthetic activity of Amazon forests; and (3 in the subsequent year after the water stresses, the greenness of Amazon forests recovered from the preceding decreases. However, as previous research shows droughts cause Amazon forests to reduce investment in tissue maintenance and defense, it is not clear whether the photosynthesis of Amazon forests will continue to recover after future water stresses, because of the accumulated damages caused by the droughts.

  14. Land use change sector contribution to the carbon historical emissions and the sustainability. Case study of the Brazilian Legal Amazon

    Energy Technology Data Exchange (ETDEWEB)

    Muylaert de Araujo, Maria Silvia [Energy and Environment Planning Program/COPPE/UFRJ, Cidade Universitaria, Centro de Tecnologia, Bloco C, sala 211, Ilha do Fundao, CEP: 21945-970, Caixa Postal: 68501, Rio de Janeiro, RJ (Brazil); Silva, Corbiniano [IVIG/COPPE/UFRJ, Cidade Universitaria, Centro de Tecnologia, Bloco I, sala 129, Ilha do Fundao, CEP: 21945-970, Caixa Postal: 68501, Rio de Janeiro, RJ (Brazil); Campos, Christiano Pires de [Petrobras Research Center, CENPES Cidade Universitaria, Ilha do Fundao, Rio de Janeiro, RJ (Brazil)

    2009-04-15

    The paper presents 5 methodological aspects for the historic land use change accountability to compare 2 databases: the Historical Database on the Global Environment of RIVM, National Institute of Public Health and the Environment, adapted by the IVIG, International Virtual Institute of Global Change of the Federal University of Rio de Janeiro, named HYDE/IVIG and the Brazilian National Institute of Spatial Research database, named INPE database. The 5 aspects here considered are geographic limits; scale; basic methodology; deforestation concept; vegetal classification. It also presents their importance for the results of the calculus of deforested areas in the Brazilian Legal Amazon case. The use of the 2 databases information for carbon emissions calculation showed to be useful in terms of magnitude but not for qualitative analysis. The calculus of deforested areas is approximately similar for the period analyzed. According to HYDE/IVIG, the Brazilian Legal Amazon land use changes representing agriculture and pasture lands, account 422,070 km{sup 2}, between 1750 and 1990 and the natural areas modified were originally classified as 3 types: tropical forest, wooded tropical forest and savanna. According to INPE, the cumulative Brazilian Legal Amazon deforestation until 1990 accounts 415,000 km{sup 2} and the natural areas modified were originally classified as 9 types. It means that different carbon contents by unit of deforestation have to be taken into account for the carbon emissions calculus. These numbers show the compatibility of the databases in terms of magnitude but the quality of the information present huge differences. (author)

  15. Viruses and bacteria in floodplain lakes along a major Amazon tributary respond to distance to the Amazon River

    Directory of Open Access Journals (Sweden)

    Rafael Marques Almeida

    2015-03-01

    Full Text Available Because of the massive water volume of the Amazon River, the Amazon tributaries have their water backed up by hundreds of kilometers upstream their mouth. This backwater effect is part of the complex hydrodynamics of Amazonian surface waters, which in turn drives the variation in concentrations of organic matter and nutrients, and also regulates planktonic communities such as viruses and bacteria. Viruses and bacteria are commonly tightly coupled, and their ecological role in aquatic food webs has been increasingly recognized. Here, we surveyed viral and bacterial abundances in 26 floodplain lakes along the Trombetas River, the largest clear-water tributary of the Amazon River’s north margin. We correlated viral and bacterial abundances with temperature, pH, dissolved inorganic carbon, dissolved organic carbon (DOC, phosphorus, nitrogen, turbidity, water transparency, partial pressure of carbon dioxide (pCO2, phytoplankton abundance and distance from the lake mouth until the confluence of the Trombetas with the Amazon River. We hypothesized that both bacterial and viral abundances would change along a latitudinal gradient, as the backwater effect becomes more intense with increased proximity to the Amazon River; different flood duration and intensity among lakes and waters with contrasting sources would cause spatial variation. Our measurements were performed during the low water period, when floodplain lakes are in their most lake-like conditions. Viral and bacterial abundances, DOC, pCO2 and water transparency increased as distance to the Amazon River increased. Most viruses were bacteriophages, as viruses were strongly linked to bacteria, but not to phytoplankton. We suggest that bacterial abundances increase in response to DOC quantity and possibly quality, consequently leading to increased viral abundances. Our results highlight that hydrodynamics plays a key role in the regulation of planktonic viral and bacterial communities in

  16. Biomedical cloud computing with Amazon Web Services.

    Science.gov (United States)

    Fusaro, Vincent A; Patil, Prasad; Gafni, Erik; Wall, Dennis P; Tonellato, Peter J

    2011-08-01

    In this overview to biomedical computing in the cloud, we discussed two primary ways to use the cloud (a single instance or cluster), provided a detailed example using NGS mapping, and highlighted the associated costs. While many users new to the cloud may assume that entry is as straightforward as uploading an application and selecting an instance type and storage options, we illustrated that there is substantial up-front effort required before an application can make full use of the cloud's vast resources. Our intention was to provide a set of best practices and to illustrate how those apply to a typical application pipeline for biomedical informatics, but also general enough for extrapolation to other types of computational problems. Our mapping example was intended to illustrate how to develop a scalable project and not to compare and contrast alignment algorithms for read mapping and genome assembly. Indeed, with a newer aligner such as Bowtie, it is possible to map the entire African genome using one m2.2xlarge instance in 48 hours for a total cost of approximately $48 in computation time. In our example, we were not concerned with data transfer rates, which are heavily influenced by the amount of available bandwidth, connection latency, and network availability. When transferring large amounts of data to the cloud, bandwidth limitations can be a major bottleneck, and in some cases it is more efficient to simply mail a storage device containing the data to AWS (http://aws.amazon.com/importexport/). More information about cloud computing, detailed cost analysis, and security can be found in references.

  17. Jotï ecogony, Venezuelan Amazon

    Science.gov (United States)

    Zent, Egleé L.

    2013-03-01

    The current environmental crisis permeates the discourse and concerns of people all over the world. Consideration of diverse environmental ethics showing the alternative ways in which people conceptualize and relate to nature and natural resources are critical for bringing about more sustainable human behaviors. After a brief review of Western historical notions of nature, this work explores the ecogony, or causal reasons, that trigger the behavior of the Jotï, an Amerindian people of the Venezuelan Amazon, with other entities and the forest that they inhabit. The analysis presented synthesizes 15 years of transdisciplinary ethno-ecological research comprising quantitative and qualitative methods (collection of herbarium voucher specimens, floristic inventories in forest plots, structured interviews focused on plot vegetation, semi-structured interviews of life-histories, participant observation, time allocation studies, food resource accounting, focal person following observations, garden crop inventories and censuses, mapping of wild resource harvest locations, among others). Jotï pragmatic and ideological tenets generate a distinctive environmental ethics based on ecogonic nodes. Notions of interdependence, humanity and person are articulated on a daily basis through several dynamics: (1) hyper-awareness of all living things’ dependence on each other and other elements of the biophysical environment at macroscales and microscales, (2) the construction of human spiritual, conscious, physical and agentive constituents from a variety of diverse botanical and zoological species and mineral components of their homeland, and (3) an understanding of the aggregate surroundings, including a significant portion of the biotic and abiotic components, as potential subjects with awareness, creativity and moral stances. This condition of interdependence confers rights and duties on all the parts. Jotï horizontal communications with and among life-forms sustain their

  18. Amazon forest response to repeated droughts

    Science.gov (United States)

    Feldpausch, T. R.; Phillips, O. L.; Brienen, R. J. W.; Gloor, E.; Lloyd, J.; Lopez-Gonzalez, G.; Monteagudo-Mendoza, A.; Malhi, Y.; Alarcón, A.; Álvarez Dávila, E.; Alvarez-Loayza, P.; Andrade, A.; Aragao, L. E. O. C.; Arroyo, L.; Aymard C., G. A.; Baker, T. R.; Baraloto, C.; Barroso, J.; Bonal, D.; Castro, W.; Chama, V.; Chave, J.; Domingues, T. F.; Fauset, S.; Groot, N.; Honorio Coronado, E.; Laurance, S.; Laurance, W. F.; Lewis, S. L.; Licona, J. C.; Marimon, B. S.; Marimon-Junior, B. H.; Mendoza Bautista, C.; Neill, D. A.; Oliveira, E. A.; Oliveira dos Santos, C.; Pallqui Camacho, N. C.; Pardo-Molina, G.; Prieto, A.; Quesada, C. A.; Ramírez, F.; Ramírez-Angulo, H.; Réjou-Méchain, M.; Rudas, A.; Saiz, G.; Salomão, R. P.; Silva-Espejo, J. E.; Silveira, M.; Steege, H.; Stropp, J.; Terborgh, J.; Thomas-Caesar, R.; Heijden, G. M. F.; Vásquez Martinez, R.; Vilanova, E.; Vos, V. A.

    2016-07-01

    The Amazon Basin has experienced more variable climate over the last decade, with a severe and widespread drought in 2005 causing large basin-wide losses of biomass. A drought of similar climatological magnitude occurred again in 2010; however, there has been no basin-wide ground-based evaluation of effects on vegetation. We examine to what extent the 2010 drought affected forest dynamics using ground-based observations of mortality and growth from an extensive forest plot network. We find that during the 2010 drought interval, forests did not gain biomass (net change: -0.43 Mg ha-1, confidence interval (CI): -1.11, 0.19, n = 97), regardless of whether forests experienced precipitation deficit anomalies. This contrasted with a long-term biomass sink during the baseline pre-2010 drought period (1998 to pre-2010) of 1.33 Mg ha-1 yr-1 (CI: 0.90, 1.74, p basin-wide impact of the 2010 drought on tree growth rates across Amazonia, which was related to the strength of the moisture deficit. This impact differed from the drought event in 2005 which did not affect productivity. Based on these ground data, live biomass in trees and corresponding estimates of live biomass in lianas and roots, we estimate that intact forests in Amazonia were carbon neutral in 2010 (-0.07 Pg C yr-1 CI:-0.42, 0.23), consistent with results from an independent analysis of airborne estimates of land-atmospheric fluxes during 2010. Relative to the long-term mean, the 2010 drought resulted in a reduction in biomass carbon uptake of 1.1 Pg C, compared to 1.6 Pg C for the 2005 event.

  19. Biomedical cloud computing with Amazon Web Services.

    Directory of Open Access Journals (Sweden)

    Vincent A Fusaro

    2011-08-01

    Full Text Available In this overview to biomedical computing in the cloud, we discussed two primary ways to use the cloud (a single instance or cluster, provided a detailed example using NGS mapping, and highlighted the associated costs. While many users new to the cloud may assume that entry is as straightforward as uploading an application and selecting an instance type and storage options, we illustrated that there is substantial up-front effort required before an application can make full use of the cloud's vast resources. Our intention was to provide a set of best practices and to illustrate how those apply to a typical application pipeline for biomedical informatics, but also general enough for extrapolation to other types of computational problems. Our mapping example was intended to illustrate how to develop a scalable project and not to compare and contrast alignment algorithms for read mapping and genome assembly. Indeed, with a newer aligner such as Bowtie, it is possible to map the entire African genome using one m2.2xlarge instance in 48 hours for a total cost of approximately $48 in computation time. In our example, we were not concerned with data transfer rates, which are heavily influenced by the amount of available bandwidth, connection latency, and network availability. When transferring large amounts of data to the cloud, bandwidth limitations can be a major bottleneck, and in some cases it is more efficient to simply mail a storage device containing the data to AWS (http://aws.amazon.com/importexport/. More information about cloud computing, detailed cost analysis, and security can be found in references.

  20. Jotï ecogony, Venezuelan Amazon

    International Nuclear Information System (INIS)

    The current environmental crisis permeates the discourse and concerns of people all over the world. Consideration of diverse environmental ethics showing the alternative ways in which people conceptualize and relate to nature and natural resources are critical for bringing about more sustainable human behaviors. After a brief review of Western historical notions of nature, this work explores the ecogony, or causal reasons, that trigger the behavior of the Jotï, an Amerindian people of the Venezuelan Amazon, with other entities and the forest that they inhabit. The analysis presented synthesizes 15 years of transdisciplinary ethno-ecological research comprising quantitative and qualitative methods (collection of herbarium voucher specimens, floristic inventories in forest plots, structured interviews focused on plot vegetation, semi-structured interviews of life-histories, participant observation, time allocation studies, food resource accounting, focal person following observations, garden crop inventories and censuses, mapping of wild resource harvest locations, among others). Jotï pragmatic and ideological tenets generate a distinctive environmental ethics based on ecogonic nodes. Notions of interdependence, humanity and person are articulated on a daily basis through several dynamics: (1) hyper-awareness of all living things’ dependence on each other and other elements of the biophysical environment at macroscales and microscales, (2) the construction of human spiritual, conscious, physical and agentive constituents from a variety of diverse botanical and zoological species and mineral components of their homeland, and (3) an understanding of the aggregate surroundings, including a significant portion of the biotic and abiotic components, as potential subjects with awareness, creativity and moral stances. This condition of interdependence confers rights and duties on all the parts. Jotï horizontal communications with and among life-forms sustain their

  1. Differentiation in the fertility of Inceptisols as related to land use in the upper Solimões river region, western Amazon.

    Science.gov (United States)

    Moreira, Fatima Maria de Souza; Nóbrega, Rafaela Simão Abrahão; Jesus, Ederson da Conceição; Ferreira, Daniel Furtado; Pérez, Daniel Vidal

    2009-12-20

    The Upper Solimões river region, western Amazon, is the homeland of indigenous populations and contains small-scale agricultural systems that are important for biodiversity conservation. Although traditional slash-and-burn agriculture is being practiced over many years, deforestation there is relatively small compared to other Amazon regions. Pastures are restricted to the vicinity of cities and do not spread to the small communities along the river. Inceptisols are the main soil order (>90%) in the area and have unique attributes including high Al content and high cation exchange capacity (CEC) due to the enrichment of the clay fraction with 2:1 secondary aluminosilicates. Despite its importance, few studies have focussed on this soil order when considering land use effects on the fertility of Amazon soils. Thus, the objective of this study was to evaluate changes in soil fertility of representative land use systems (LUSs) in the Upper Solimões region, namely: primary rainforest, old secondary forest, young secondary forest, agroforestry, pasture and agriculture. LUSs were significantly differentiated by the chemical attributes of their topsoil (0-20 cm). Secondary forests presented soil chemical attributes more similar to primary rainforest areas, while pastures exhibited the highest dissimilarity from all the other LUSs. As a whole, soil chemical changes among Inceptisols dominated LUSs showed patterns that were distinct from those reported from other Amazon soils like Oxisols and Ultisols. This is probably related to the presence of high-activity clays enriched in exchangeable aluminum that heavily influenced the soil chemical reactions over the expected importance of organic matter found in most studies conducted over Oxisol and Ultisol. PMID:19853281

  2. Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

    Science.gov (United States)

    Razavizadeh, Mahmoud; Jamshidi, Masoud

    2016-08-01

    Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

  3. Microbial fuel cell anode modified by chemical oxidation%化学氧化改性微生物燃料电池阳极

    Institute of Scientific and Technical Information of China (English)

    周宇; 刘中良; 侯俊先; 杨斯琦; 李艳霞; 邱文革

    2015-01-01

    浓HNO3和酸性K2Cr2O7都具有一定的氧化性,分别利用浓HNO3和酸性K2Cr2O7对阳极碳布进行氧化改性处理。通过红外光谱测试显示,碳布表面附着了羟基(—OH)和羧基(—COOH)。通过扫描电镜观察,碳布经过氧化改性后表面明显变粗糙。同时,循环伏安曲线(CV)和交流阻抗曲线(EIS)测试表明,经过改性后的碳布具有良好的电化学特性。分别以经过浓HNO3和酸性K2Cr2O7改性处理后的碳布作为微生物燃料电池(MFC)的阳极,获得的最大功率密度分别为291.11 mW·m−2和438.08 mW·m−2,比未经过改性处理的碳布阳极的功率密度分别提升了21%和82%。%Oxidants of nitric acid and acidic potassium dichromate were used to modify anode carbon cloths. Modification was completed by first putting the carbon cloth into nitric acid or acidic potassium dichromate at a given temperature, soaking for 30 min and then rinsing with de-ionized water until no variation in pH and finally putting into a vacuum dryer, drying for 12 h. Fourier transform infrared spectroscopy measurements indicated that many hydroxyls and carboxyls were attached on the carbon cloth surface after modification. SEM results showed that the surface of carbon cloth became rougher than the unmodified one. In addition, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements demonstrated that both modified anodes had excellent electrochemical properties. Using the modified carbon cloths as microbial fuel cell (MFC) anodes respectively, such MFCs yielded maximum power densities of 291.11 mW·m−2 and 438.08 mW·m−2, 21%and 82%higher than that of the MFC with unmodified carbon cloth anode respectively.

  4. Deforestation in the Brazilian Amazon: A Classroom Project.

    Science.gov (United States)

    Nijman, Jan; Hill, A. David

    1991-01-01

    Presents a classroom project dealing with tropical deforestation in the Brazilian Amazon. Addresses environmental consequences and economic, social, and political causes. Involves both lectures and individual research and reports by student groups on deforestation causes. Includes a note-playing activity in which students make recommendations for…

  5. Extreme Drought Events Revealed in Amazon Tree Ring Records

    Science.gov (United States)

    Jenkins, H. S.; Baker, P. A.; Guilderson, T. P.

    2010-12-01

    The Amazon basin is a center of deep atmospheric convection and thus acts as a major engine for global hydrologic circulation. Yet despite its significance, a full understanding of Amazon rainfall variability remains elusive due to a poor historical record of climate. Temperate tree rings have been used extensively to reconstruct climate over the last thousand years, however less attention has been given to the application of dendrochronology in tropical regions, in large part due to a lower frequency of tree species known to produce annual rings. Here we present a tree ring record of drought extremes from the Madre de Dios region of southeastern Peru over the last 190 years. We confirm that tree ring growth in species Cedrela odorata is annual and show it to be well correlated with wet season precipitation. This correlation is used to identify extreme dry (and wet) events that have occurred in the past. We focus on drought events identified in the record as drought frequency is expected to increase over the Amazon in a warming climate. The Cedrela chronology records historic Amazon droughts of the 20th century previously identified in the literature and extends the record of drought for this region to the year 1816. Our analysis shows that there has been an increase in the frequency of extreme drought (mean recurrence interval = 5-6 years) since the turn of the 20th century and both Atlantic and Pacific sea surface temperature (SST) forcing mechanisms are implicated.

  6. Commons management and ecotourism: Ethnographic evidence from the Amazon

    NARCIS (Netherlands)

    Stronza, Amanda Lee

    2010-01-01

    TThe paper evaluates the relationship between ecotourism and commons management. Social and economic impacts of ecotourism in an indigenous village in the Peruvian Amazon are considered in relation to opportunities for collective action to manage common pool resources, including wildlife, forests, a

  7. People, soil and manioc interactions in the upper Amazon region

    NARCIS (Netherlands)

    Peña Venegas, C.P.

    2015-01-01

    Abstract Clara Patricia Peña Venegas (2015). People, soil and manioc interactions in the upper Amazon region. PhD thesis, Wageningen University, The Netherlands, with summaries in English and Dutch, 210 pp. The presence of anthropogenic soils, or Amazonian Dark   Ea

  8. The Amazon region: tropical deforestation, biogeochemical cycles and the climate

    NARCIS (Netherlands)

    Kabat, P.; Andreae, M.O.; Silva-Dias, M.A.; Veraart, J.A.; Brink, N.J.

    2003-01-01

    The biogeochemical cycling of carbon, water, energy, aerosols, and trace gases in the Amazon Basin, and the interactions between deforestation, rainfall and climate were all investigated in this programme as a part of an integrated cluster of inter-linked and complementary research projects. These i

  9. Future of oil and gas development in the western Amazon

    International Nuclear Information System (INIS)

    The western Amazon is one of the world’s last high-biodiversity wilderness areas, characterized by extraordinary species richness and large tracts of roadless humid tropical forest. It is also home to an active hydrocarbon (oil and gas) sector, characterized by operations in extremely remote areas that require new access routes. Here, we present the first integrated analysis of the hydrocarbon sector and its associated road-building in the western Amazon. Specifically, we document the (a) current panorama, including location and development status of all oil and gas discoveries, of the sector, and (b) current and future scenario of access (i.e. access road versus roadless access) to discoveries. We present an updated 2014 western Amazon hydrocarbon map illustrating that oil and gas blocks now cover 733 414 km2, an area much larger than the US state of Texas, and have been expanding since the last assessment in 2008. In terms of access, we documented 11 examples of the access road model and six examples of roadless access across the region. Finally, we documented 35 confirmed and/or suspected untapped hydrocarbon discoveries across the western Amazon. In the Discussion, we argue that if these reserves must be developed, use of the offshore inland model—a method that strategically avoids the construction of access roads—is crucial to minimizing ecological impacts in one of the most globally important conservation regions. (letter)

  10. Mimivirus Circulation among Wild and Domestic Mammals, Amazon Region, Brazil

    OpenAIRE

    Dornas, Fábio P.; Rodrigues, Felipe P.; Boratto, Paulo V.M.; Silva, Lorena C. F.; Ferreira, Paulo C. P.; Bonjardim, Cláudio A.; Trindade, Giliane S; Kroon, Erna G.; La Scola, Bernard; Abrahão, Jônatas S

    2014-01-01

    To investigate circulation of mimiviruses in the Amazon Region of Brazil, we surveyed 513 serum samples from domestic and wild mammals. Neutralizing antibodies were detected in 15 sample pools, and mimivirus DNA was detected in 9 pools of serum from capuchin monkeys and in 16 pools of serum from cattle.

  11. Mimivirus circulation among wild and domestic mammals, Amazon Region, Brazil.

    Science.gov (United States)

    Dornas, Fábio P; Rodrigues, Felipe P; Boratto, Paulo V M; Silva, Lorena C F; Ferreira, Paulo C P; Bonjardim, Cláudio A; Trindade, Giliane S; Kroon, Erna G; La Scola, Bernard; Abrahão, Jônatas S

    2014-03-01

    To investigate circulation of mimiviruses in the Amazon Region of Brazil, we surveyed 513 serum samples from domestic and wild mammals. Neutralizing antibodies were detected in 15 sample pools, and mimivirus DNA was detected in 9 pools of serum from capuchin monkeys and in 16 pools of serum from cattle. PMID:24564967

  12. Staphylococcus aureus causing tropical pyomyositis, Amazon Basin, Peru.

    NARCIS (Netherlands)

    Garcia, C.; Hallin, M.; Deplano, A.; Denis, O.; Sihuincha, M.; Groot, R. de; Gotuzzo, E.; Jacobs, J.

    2013-01-01

    We studied 12 Staphylococcus aureus isolates causing tropical pyomyositis in the Amazon Basin of Peru. All isolates were methicillin-susceptible; 11 carried Panton-Valentine leukocidin-encoding genes, and 5 belonged to multilocus sequence type 25 and possessed an extensive set of enterotoxins. Our f

  13. Andes hantavirus variant in rodents, southern Amazon Basin, Peru.

    Science.gov (United States)

    Razuri, Hugo; Tokarz, Rafal; Ghersi, Bruno M; Salmon-Mulanovich, Gabriela; Guezala, M Claudia; Albujar, Christian; Mendoza, A Patricia; Tinoco, Yeny O; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah; Nichol, Stuart T; Hirschberg, David L; Lipkin, W Ian; Bausch, Daniel G; Montgomery, Joel M

    2014-02-01

    We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.

  14. Aerosol retrieval from OMI: Applications to the amazon bassin

    NARCIS (Netherlands)

    Curier, R.L.; Veefkind, J.P.; Veilhmann, B.; Braak, R.; Torres, O.; Leeuw, G.de

    2007-01-01

    We present the aerosol optical depth retrieved from OMI measurements using the multi-wavelengthm algorithm for two different environments: over Western Europe where the aerosols are weakly absorbing and over the Amazon basin where aerosol optical properties are governed by biomass burning. The resul

  15. Mayaro virus infection, Amazon Basin region, Peru, 2010-2013.

    Science.gov (United States)

    Halsey, Eric S; Siles, Crystyan; Guevara, Carolina; Vilcarromero, Stalin; Jhonston, Erik J; Ramal, Cesar; Aguilar, Patricia V; Ampuero, Julia S

    2013-11-01

    During 2010-2013, we recruited 16 persons with confirmed Mayaro virus infection in the Peruvian Amazon to prospectively follow clinical symptoms and serologic response over a 12-month period. Mayaro virus infection caused long-term arthralgia in more than half, similar to reports of other arthritogenic alphaviruses.

  16. Placentation in dolphins from the Amazon River Basin

    DEFF Research Database (Denmark)

    da Silva, Vera M F; Carter, Anthony M; Ambrosio, Carlos E;

    2007-01-01

    A recent reassessment of the phylogenetic affinities of cetaceans makes it timely to compare their placentation with that of the artiodactyls. We studied the placentae of two sympatric species of dolphin from the Amazon River Basin, representing two distinct families. The umbilical cord branched...

  17. Backwater effects in the Amazon River basin of Brazil

    Science.gov (United States)

    Meade, R.H.; Rayol, J.M.; Da Conceicao, S.C.; Natividade, J.R.G.

    1991-01-01

    The Amazon River mainstem of Brazil is so regulated by differences in the timing of tributary inputs and by seasonal storage of water on floodplains that maximum discharges exceed minimum discharges by a factor of only 3. Large tributaries that drain the southern Amazon River basin reach their peak discharges two months earlier than does the mainstem. The resulting backwater in the lowermost 800 km of two large southern tributaries, the Madeira and Puru??s rivers, causes falling river stages to be as much as 2-3 m higher than rising stages at any given discharge. Large tributaries that drain the northernmost Amazon River basin reach their annual minimum discharges three to four months later than does the mainstem. In the lowermost 300-400 km of the Negro River, the largest northern tributary and the fifth largest river in the world, the lowest stages of the year correspond to those of the Amazon River mainstem rather than to those in the upstream reaches of the Negro River. ?? 1991 Springer-Verlag New York Inc.

  18. Kindling: The Amazon e-Reader as an Educational Tool

    Science.gov (United States)

    Brezicki, Colin

    2011-01-01

    The revolutionary electronic reading device, Amazon's Kindle, is already obsolete. Such is the breakneck speed of technology that the machine touted to spell the death of printed books is already heading for the scrap heap, replaced by e-readers like the iPad that access the Internet, make phone calls, download movies, and connect users with all…

  19. Long-term decline of the Amazon carbon sink

    Science.gov (United States)

    Brienen, R. J. W.; Phillips, O. L.; Feldpausch, T. R.; Gloor, E.; Baker, T. R.; Lloyd, J.; Lopez-Gonzalez, G.; Monteagudo-Mendoza, A.; Malhi, Y.; Lewis, S. L.; Vásquez Martinez, R.; Alexiades, M.; Álvarez Dávila, E.; Alvarez-Loayza, P.; Andrade, A.; Aragão, L. E. O. C.; Araujo-Murakami, A.; Arets, E. J. M. M.; Arroyo, L.; Aymard C., G. A.; Bánki, O. S.; Baraloto, C.; Barroso, J.; Bonal, D.; Boot, R. G. A.; Camargo, J. L. C.; Castilho, C. V.; Chama, V.; Chao, K. J.; Chave, J.; Comiskey, J. A.; Cornejo Valverde, F.; da Costa, L.; de Oliveira, E. A.; di Fiore, A.; Erwin, T. L.; Fauset, S.; Forsthofer, M.; Galbraith, D. R.; Grahame, E. S.; Groot, N.; Hérault, B.; Higuchi, N.; Honorio Coronado, E. N.; Keeling, H.; Killeen, T. J.; Laurance, W. F.; Laurance, S.; Licona, J.; Magnussen, W. E.; Marimon, B. S.; Marimon-Junior, B. H.; Mendoza, C.; Neill, D. A.; Nogueira, E. M.; Núñez, P.; Pallqui Camacho, N. C.; Parada, A.; Pardo-Molina, G.; Peacock, J.; Peña-Claros, M.; Pickavance, G. C.; Pitman, N. C. A.; Poorter, L.; Prieto, A.; Quesada, C. A.; Ramírez, F.; Ramírez-Angulo, H.; Restrepo, Z.; Roopsind, A.; Rudas, A.; Salomão, R. P.; Schwarz, M.; Silva, N.; Silva-Espejo, J. E.; Silveira, M.; Stropp, J.; Talbot, J.; Ter Steege, H.; Teran-Aguilar, J.; Terborgh, J.; Thomas-Caesar, R.; Toledo, M.; Torello-Raventos, M.; Umetsu, R. K.; van der Heijden, G. M. F.; van der Hout, P.; Guimarães Vieira, I. C.; Vieira, S. A.; Vilanova, E.; Vos, V. A.; Zagt, R. J.

    2015-03-01

    Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.

  20. Modification of Atmospheric Circulations and Transports due to Amazon Deforestation

    Science.gov (United States)

    Badger, A.; Dirmeyer, P.

    2013-12-01

    Land-use change (LUC) has generally been considered a local environmental issue, but it is now becoming a force of global importance. LUC occurs on local scales, with real world social and economic benefits, that can potentially cause ecological degradation. Large-scale LUC, such as deforestation in the Amazon, can have a significant local affect on the climate and has the potential to impact the regional and global climate systems. Previous climate modeling studies have shown non-local responses due to Amazon deforestation, however, a common flaw in these studies is the use of prescribed ocean conditions, which can dampen the global response. Using fully coupled modeling simulations with the Community Earth System Model version 1.2.0, the Amazon rainforest has been replaced with a distribution of representative tropical crops. The degree of modification to the general circulation due to heating anomalies in the tropics as a response to the removal of the Amazon rainforest is quantified. Most notably, modifications to the Hadley and Walker circulations, the two fundamental circulations mediating the climate at low latitudes, occur. Coupling these circulation changes with sensible heat and latent heat fluxes, atmospheric transports of heat and moisture are affected both regionally and globally.

  1. Learning big data with Amazon Elastic MapReduce

    CERN Document Server

    Singh, Amarkant

    2014-01-01

    This book is aimed at developers and system administrators who want to learn about Big Data analysis using Amazon Elastic MapReduce. Basic Java programming knowledge is required. You should be comfortable with using command-line tools. Prior knowledge of AWS, API, and CLI tools is not assumed. Also, no exposure to Hadoop and MapReduce is expected.

  2. A chemical strategy to improve the fluorescence environments of erbium-ions doped into organically modified hybrid glasses for laser amplifier applications

    International Nuclear Information System (INIS)

    Bridged polysilsesquioxanes, a class of hybrid organic/inorganic siloxanes, are employed to manipulate the fluorescence environments of rare-earth metal ions. The performance of silsequioxanes containing rare-earth ions in optical devices significantly relies on host materials' properties. We have developed organically modified fluoroalkylene-bridged polysilsesquioxanes doped with Er3+/CdSe nano-particles. Solid state silicon NMR analysis of undoped xerogels indicate an enhanced condensation in fluorinated xerogel compared to that of alkylene-bridged silsesquioxanes. Fluoroalkylene-bridged xerogel containing Er3+-ions shows significantly reduced absorptions at the 1540 nm by reducing amounts of uncondensed hydroxyl groups. The presence of CdSe nano-particles influences the fluorescence environment of Er3+-ions in different glassy hosts, resulting in the increased fluorescence intensity

  3. Achieving zero deforestation in the Brazilian Amazon: What is missing?

    Directory of Open Access Journals (Sweden)

    Paulo Moutinho

    2016-09-01

    Full Text Available Abstract Amazon deforestation causes severe climatic and ecological disruptions, with negative consequences for the livelihood of forest-dependent peoples. To avoid further disruptions, Brazil will need to take bold steps to eliminate both illegal and legal Amazon deforestation over the short term. Amazon deforestation declined by 70% between 2005 and 2014 due to drops in commodity prices and interventions by federal and state governments, such as law enforcement campaigns and credit restrictions for landowners who deforest illegally. Despite these impressive achievements, Brazil still deforests 5,000 km2 of Amazonian forests each year. How then will Brazil eliminate Amazon deforestation altogether if the country is only committed to cut illegal deforestation by 2030—as stated in its Intended Nationally Determined Contributions (iNDC to the 2015 climate change treaty meeting in Paris? Here we provide an analysis of the major socio-economic-political threats that could constrain Brazil from achieving its current goals. We then propose six fundamental strategies to help Brazil achieve a more ambitious goal to eliminate all major legal and illegal Amazon deforestation. These strategies involve bringing social and environmental safeguards to the infrastructure plans in the region, consolidating and expanding positive incentives for the production of sustainable commodities, establishing a new policy to guarantee the social and environmental sustainability of rural settlements, fully implementing the national legislation protecting forests (the Forest Code, protecting the land rights of indigenous people and traditional communities, and expanding the existing network of protected areas, allocating the 80 million hectares of not designated public forests as protected areas or areas for sustainable use of timber and non-timber forest products. The implementation of these strategies however depends on the formulation of a new development paradigm that

  4. Seroprevalence of Toxoplasma gondii in free-living Amazon river dolphins (Inia geoffrensis) from central Amazon, Brazil

    Science.gov (United States)

    Toxoplasma gondii is an important pathogen in aquatic mammals and its presence in these animals may indicate water contamination of aquatic environment by oocysts. Serum samples from 95 dolphins from free-living Amazon River dolphins (Inia geoffrensis) from Sustainable Development Reserve Mamirauá (...

  5. Seroprevalence of Toxoplasma gondii in free-living amazon river dolphins (Inia geoffrensis) from central Amazon, Brazil

    Science.gov (United States)

    Toxoplasma gondii is an important pathogen in aquatic mammals and its presence in these animals may indicate water contamination of aquatic environment by oocysts. Serum samples from 95 dolphins from free-living Amazon River dolphins (Inia geoffrensis) from Sustainable Development Reserve Mamirauá (...

  6. Ecological diversity of Trypanosoma cruzi transmission in the Amazon basin. The main scenaries in the Brazilian Amazon.

    Science.gov (United States)

    Coura, J R; Junqueira, A C V

    2015-11-01

    The ecological diversity of Trypanosoma cruzi transmission in the Brazilian Amazon region is directly interlinked with the parasite's extensive reservoir, composed of 33 species of wild mammals within the following orders: Marsupialia, Chiroptera, Rodentia, Xenarthra, Carnivora and Primates; and of 16 species of wild triatomines, of which ten may be infected with T. cruzi. Four scenarios for the diversity of T. cruzi transmission in the Brazilian Amazon region are evident: (i) T. cruzi transmission between vectors and wild mammals, which is characterized as a wild enzooty encompassing the entire Amazon basin; (ii) accidental T. cruzi transmission from vectors and wild mammals to humans, when they invade the wild ecotope or when these vectors and wild mammals invade human homes; (iii) occupational Chagas disease among piassava (Leopoldinia piassaba) palm fiber gatherers, transmitted by the vector Rhodnius brethesi, for which these palm trees are the specific ecotope; (IV) oral T. cruzi transmission to humans through food contamination, particularly in juices from plants such as assai, which today is considered to be endemic in the Brazilian Amazon region, with more than 1500 cases notified.

  7. Late Miocene onset of the Amazon River and the Amazon deep-sea fan: Evidence from the Foz do Amazonas Basin

    NARCIS (Netherlands)

    J. Figueiredo; C. Hoorn; P. van der Ven; E. Soares

    2009-01-01

    New biostratigraphic, isotopic, and well log data from exploration wells on the outer continental shelf and uppermost Amazon deep-sea fan, Brazil, reveal that the Amazon River was initiated as a transcontinental river between 11.8 and 11.3 Ma ago (middle to late Miocene), and reached its present sha

  8. New sediment budget calculations for the submarine Amazon Delta indicates enhanced modern sediment fluxes of the Amazon system

    Science.gov (United States)

    Schwenk, T.; Haberkern, J.; Mulitza, S.; Chiessi, C. M.

    2013-12-01

    The submarine Amazon Delta is one major sink in the Amazon source-to-sink system. It is estimated, that the Amazon transports around 1200 Mt/yr. Around 50% of this river sediment load, namely 400 - 800 Mt/yr, is stored on the submarine delta, leading to sedimentation rates of decimeters per year (Nittrouer et al., 1995). The majority of the remaining sediments is deposited on the lower delta plain of the Amazon, but another significant portion is accumulated at the Amapa shoreline or is bypassed further northwestwards. These sediment budget calculations are mainly based on radioisotopic profiles measured at sediment cores in the frame of the AmasSeds project, which was carried out in the 1980ties and 1990ties (Nittrouer et al., 1995). Here we present another approach for calculating mass fluxes in the Amazon system. Within the Project AMADEUS, a cooperation between the MARUM, Bremen, Germany and the University Sao Paulo, Brazil, high-resolution seismic multichannel seismic data and sediment echosounder data (PARASOUND) were collected during Cruise MSM20/3 in February/March 2012. Main emphases of the surveying were set to the forset and bottomset of the delta, where most of the accretion occurs. A special outcome of the new data is the comparison with PARASOUND data collected in 1996 during Cruise M34/4. Due to several crossing points of both data sets it is now possible to carry out direct measurements of the accumulation during these 16 years. Another time horizon is a prominent unconformity spreading over the submarine delta, since the sedimentation on top of this unconformity had been dated to start roughly 100 yrs ago (Sommerfield et al., 1995). Mapping of this unconformity as well as the reflector representing the seafloor of 1996 gives the opportunity to calculate volumes and mass of the sediment stored within the survey area for two different time spans. First calculations show, that the sediment accumulation on the submarine delta since 1996 is

  9. Contribution to the study of physico-chemical properties of surfaces modified by laser treatment. Application to the enhancement of localized corrosion resistance of stainless steels

    International Nuclear Information System (INIS)

    Metallic materials are more and more used in severe conditions with particularly strong request for improving their behavior in aggressive environment and especially over long periods. The objective of this PhD work is to estimate the potentiality of a laser surface melting treatment on the improvement of the stainless steel 304L corrosion resistance, surface treatments by laser can be revisited on the basis of a recent change in the laser technology. In the frame of this work, a nano-pulsed laser fiber was chosen: it allows the treated surface to be melted for few microns in depth, followed by an ultra-fast solidification occurring with cooling rates up to 1011 K/s. The combination of these processes leads to the elimination of the surface defects, the formation (trapping) of metastable phases, the segregation of chemical elements and the growth of a new oxide layer which properties are governed by the laser parameters. To correlate these latter to the electrochemical reactivity of the surface, the influence of two laser parameters on the physico-chemical properties of the surface was studied: the laser power and the overlap of the laser impacts. To support this approach, the pitting corrosion resistance of the samples was determined by standard electrochemical tests. For specific laser parameters, the pitting potential of a 304L stainless steel was increased by more than 500 mV corresponding to an important enhancement in localized corrosion resistance in chloride environment. The interdependence of the different phenomena resulting from the laser treatment lead to a quite complex prioritization of their role on the sensibility of the 304L. However, it was demonstrated that the nature of the thermal oxide formed during the laser surface melting and the induced defects are first-order parameters for the initiation of pits. (author)

  10. Estudo teórico de propriedades ópticas não-lineares de nanotubos de carbono de parede única quimicamente modificados Theoretical analysis of non-linear optical properties for chemically modified single wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Antônio M. Da Silva Jr.

    2009-01-01

    Full Text Available Structure and first hyperpolarizability for a series of armchair a(5,5 chemically modified carbon nanotubes (CNT were calculated at semiempirical and density functional levels of theory. The 4,4´-substituted stilbenes were selected as chromophore with substituents at position 4´ set to X=NO2, H, Cl, OH and NH2. The calculated values for static first hyperpolarizability (β were almost linearly dependent on the electronic effect of the group X, increasing from NO2 to NH2. At DFT level the effect of inserting the chromophore in the CNT surface was to enhance the β value up to 70% relative to the free 4,4´-substituted stilbene.

  11. The Late Miocene paleogeography of the Amazon Basin and the evolution of the Amazon River system

    Science.gov (United States)

    Latrubesse, Edgardo M.; Cozzuol, Mario; da Silva-Caminha, Silane A. F.; Rigsby, Catherine A.; Absy, Maria Lucia; Jaramillo, Carlos

    2010-05-01

    basin, and became instead an erosional area that contributed sediments to the Amazon fluvial system. At that time, the lowland fluvial systems of southwestern Amazonia (the Purus, Jurua and Javarí basins) become isolated from the Andes by the newly formed north-flowing Ucayali system and south-east flowing Madre de Dios System. It was during the early Pliocene that the Amazon fluvial system integrated regionally and acquired its present appearance, and also when it started to drain water and sediments on a large scale to the Atlantic Ocean.

  12. O emprego de quitosana quimicamente modificada com anidrido succínico na adsorção de azul de metileno The use of chemical modified chitosam with succinic anhydride in the methylene blue adsorption

    Directory of Open Access Journals (Sweden)

    Ilauro S. Lima

    2006-06-01

    Full Text Available The adsorption capacity of alpha-chitosan and its modified form with succinic anhydride was compared with the traditional adsorbent active carbon by using the dye methylene blue, employed in the textile industry. The isotherms for both biopolymers were classified as SSA systems in the Giles model, more specifically in L class and subgroup 3. The dye concentration in the supernatant in the adsorption assay was determined through electronic spectroscopy. By calorimetric titration thermodynamic data of the interaction between methyene blue and the chemically modified chitosan at the solid/liquid interface were obtained. The enthalpy of the dye/chitosan interaction gave 2.47 ± 0.02 kJ mol-1 with an equilibrium constant of 7350 ± 10 and for the carbon/dye interaction this constant gave 5951 ± 8. The spontaneity of these adsorptions are reflected by the free Gibbs energies of -22.1 ± 0.4 and -21.5 ± 0.2 kJ mol-1, respectively, found for these systems. This new adsorbent derived from a natural polysaccharide is as efficient as activated carbon. However 97% of the bonded dye can be eluted by sodium chloride solution, while this same operation elutes only 42% from carbon. Chitosan is efficient in dye removal with the additional advantage of being cheap, non-toxic, biocompatible and biodegradable.

  13. Inclusion Behavior of Chemical Modified β-cyclodextrin in Alcohol/Water Mixed Solvents%化学修饰环糊精在醇/水混合溶剂中的包结行为

    Institute of Scientific and Technical Information of China (English)

    解宏智; 吴世康

    2000-01-01

    A comparative study on the fluorescence behavior of the chemical modified β -cyclodextrin appended a N,N-dimethylamino-chalcone group (DMAC-CD) and the non-modified β-CD mixed with free dimethylamino-chalcone (DMAC+ CD) in alcohol/water mixed solvents have been carried out in this work.The fluorescence data obtained— — maximum peak wavelength and emission intensity— — indicates that the inclusion behavior of the above-mentioned systems is obviously different in mixed alcohol/water solvents.The solvent-induced multi-component complex formation and dissociation and the effect of polarity and size of alcohol used have been also studied carefully by variation of the fluorescence spectroscopic characters.The result indicates that the self-inclusion complex of DMAC-CD has a higher stability in mixed alcohol/water solvents than that in the DMAC + β -CD system.The obtained results and the observed phenomena have been discussed in details.

  14. A novel thin-layer amperometric detector based on chemically modified ring-disc electrode and its application for simultaneous measurements of nitric oxide and nitrite in rat brain combined with in vivo microdialysis.

    Science.gov (United States)

    Mao, L; Shi, G; Tian, Y; Liu, H; Jin, L; Yamamoto, K; Tao, S; Jin, J

    1998-08-01

    A novel thin-layer amperometric detector (TLAD) based on chemically modified ring-disc electrode and its application for simultaneous measurements of nitric oxide (NO) and nitrite (NO(2)(-)) in rat brain were demonstrated in this work. The ring-disc electrode was simultaneously sensitive to nitric oxide (NO) and nitrite (NO(2)(-)) by modifying its inner disc with electropolymerized film of cobalt(II) tetraaminophthalocyanine (polyCoTAPc)/Nafion and its outer ring with poly(vinylpyridine) (PVP), respectively. The ring-disc electrode was used to constitute a novel TLAD in radial flow cell for simultaneous measurements of NO and NO(2)(-) in rat brain combined with techniques of high performance liquid chromatography (HPLC) and in vivo microdialysis. It was found that the basal concentration of NO in the caudate nucleus of rat brain is lower than 1.0x10(-7) mol l(-1), NO(2)(-) concentration is 5.0x10(-7) mol l(-1) and NO exists in brain maybe mainly in the form of its decomposed product. PMID:18967286

  15. Changes in the microbiological and chemical characteristics of white bread during storage in paper packages modified with Ag/TiO2-SiO2, Ag/N-TiO2 or Au/TiO2.

    Science.gov (United States)

    Peter, Anca; Mihaly-Cozmuta, Leonard; Mihaly-Cozmuta, Anca; Nicula, Camelia; Ziemkowska, Wanda; Basiak, Dariusz; Danciu, Virginia; Vulpoi, Adriana; Baia, Lucian; Falup, Anca; Craciun, Grigore; Ciric, Alexandru; Begea, Mihaela; Kiss, Claudia; Vatuiu, Daniela

    2016-04-15

    Microbiological and chemical characteristics of white bread during storage in paper-packages modified with Ag/TiO2-SiO2, Ag/N-TiO2 or Au/TiO2 were investigated. The whiteness and the water retention of the modified packages were slightly superior to those exhibited by the reference sample, as the color of the composite was lighter. The water retention was very good especially for the Ag/TiO2-SiO2-paper. These improvements can be associated with the high specific surface area and with the low agglomeration tendency of Ag nanoparticles in comparison with the Au ones. The preservation activity of the composites for the bread storage is positively influenced by photoactivity and presence of nano-Ag. Packages Ag/TiO2-SiO2-paper and Ag/N-TiO2-paper can find their applicability for extending the shelf life of bread by 2 days as compared with the unmodified paper-package. No influence of the Au/TiO2 on the extending the shelf life of bread was observed. PMID:26617018

  16. New Inorganic-organic Hybrid Compound Containing One Dimensional Keggin Polyoxometalate[SiW11O39Co]6- Chains:Preparation,Characterization and Application in Chemically Bulk-modified Electrode

    Institute of Scientific and Technical Information of China (English)

    WANG Xiu-li; LIN Hong-yan; LIU Guo-cheng; CHEN Bao-kuan; BI Yan-feng

    2008-01-01

    A new inorganic-organic hybrid compound based on polyoxometalate and organic ligand formulated as (H2bpp)3[SiW11O39Co]~2H2O(1)[bpp=1,3-bis(4-pyridyl)propane]was hydrothermally synthesized and structurally characterized by elemental analysis,single-crystal X-ray diffraction,IR,TG,and cyclic voltammetry.Single-crystal X-ray diffraction analysis reveals that compound 1 consists of interesting cobalt-monosubstituted POMs one dimensional chain together with protonated bpp ligands.Additionally,the polyoxoanions combined with the discrete organic substrates by hydrogen bond interactions to afford a supramolecular 3D network structure.The hybrid compound 1 was used as a bulk modifier to fabricate a three-dimensional chemically modified carbon paste electrode(1-CPE)by direct mixing.The electrochemical behavior and electrocatalysis of 1-CPE were studied in detail.The results indicate that 1-CPE has good electrocatalytic activities toward the reduction of nitrite or bromate in 1mol/L H2SO4 aqueous solution.1-CPE shows remarkable stability that can be ascribed to the insolubility of compound 1 and the supramolecular interactions existed between 1D POM anion chains and organic ligand bpp,which is very important for practical applications in electrode modification.

  17. Changes in the microbiological and chemical characteristics of white bread during storage in paper packages modified with Ag/TiO2-SiO2, Ag/N-TiO2 or Au/TiO2.

    Science.gov (United States)

    Peter, Anca; Mihaly-Cozmuta, Leonard; Mihaly-Cozmuta, Anca; Nicula, Camelia; Ziemkowska, Wanda; Basiak, Dariusz; Danciu, Virginia; Vulpoi, Adriana; Baia, Lucian; Falup, Anca; Craciun, Grigore; Ciric, Alexandru; Begea, Mihaela; Kiss, Claudia; Vatuiu, Daniela

    2016-04-15

    Microbiological and chemical characteristics of white bread during storage in paper-packages modified with Ag/TiO2-SiO2, Ag/N-TiO2 or Au/TiO2 were investigated. The whiteness and the water retention of the modified packages were slightly superior to those exhibited by the reference sample, as the color of the composite was lighter. The water retention was very good especially for the Ag/TiO2-SiO2-paper. These improvements can be associated with the high specific surface area and with the low agglomeration tendency of Ag nanoparticles in comparison with the Au ones. The preservation activity of the composites for the bread storage is positively influenced by photoactivity and presence of nano-Ag. Packages Ag/TiO2-SiO2-paper and Ag/N-TiO2-paper can find their applicability for extending the shelf life of bread by 2 days as compared with the unmodified paper-package. No influence of the Au/TiO2 on the extending the shelf life of bread was observed.

  18. Evaluation of chemically modified Ti–5Mo–3Fe alloy surface: Electrochemical aspects and in vitro bioactivity on MG63 cells

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A. Madhan [Center of Research Excellence in Corrosion, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Sudhagar, P. [Energy Materials Laboratory, WCU Program Department of Energy Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Ramakrishna, Suresh [Graduate School of Biomedical Science and Engineering/College of Medicine, Hanyang University, Sungdong-gu, Seoul (Korea, Republic of); Kang, Yong Soo [Energy Materials Laboratory, WCU Program Department of Energy Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Hyongbum [Graduate School of Biomedical Science and Engineering/College of Medicine, Hanyang University, Sungdong-gu, Seoul (Korea, Republic of); Gasem, Zuhair M. [Center of Research Excellence in Corrosion, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Rajendran, N., E-mail: nrajendran@annauniv.edu [Department of Chemistry, Anna University, Chennai (India)

    2014-07-01

    Ti–5Mo–3Fe (TMF) alloy is a newly developed β-titanium alloy with low modulus, and it has been deemed as suitable material for dental or orthopaedic implant. The aim of the present study is to evaluate the effect of alkali and hydrogen peroxide treatment on the corrosion and biological performance of TMF surface. The phases, morphology with chemical composition and topography of the treated surface were examined by X-ray diffraction, scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDAX) analysis and atomic force microscopy (AFM), respectively. Micro hardness of treated substrates was measured using Vicker's micro hardness method. The electrochemical studies were carried out using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) measurements. In order to describe the bio-activity, contact angle measurements, in vitro characterisation and cell culture studies were performed for treated TMF surfaces in simulated body fluid (SBF) and MG63 cells. All these observations showed that the NaOH treatment is the most appropriate method for TMF alloy which exhibited superior biocompatibility and enhanced corrosion protection performance due to their hydrophilic, smooth, compact porous surface morphology than that of other substrates.

  19. Biogenic cloud nuclei in the central Amazon during the transition from wet to dry season

    Science.gov (United States)

    Whitehead, James D.; Darbyshire, Eoghan; Brito, Joel; Barbosa, Henrique M. J.; Crawford, Ian; Stern, Rafael; Gallagher, Martin W.; Kaye, Paul H.; Allan, James D.; Coe, Hugh; Artaxo, Paulo; McFiggans, Gordon

    2016-08-01

    The Amazon basin is a vast continental area in which atmospheric composition is relatively unaffected by anthropogenic aerosol particles. Understanding the properties of the natural biogenic aerosol particles over the Amazon rainforest is key to understanding their influence on regional and global climate. While there have been a number of studies during the wet season, and of biomass burning particles in the dry season, there has been relatively little work on the transition period - the start of the dry season in the absence of biomass burning. As part of the Brazil-UK Network for Investigation of Amazonian Atmospheric Composition and Impacts on Climate (BUNIAACIC) project, aerosol measurements, focussing on unpolluted biogenic air masses, were conducted at a remote rainforest site in the central Amazon during the transition from wet to dry season in July 2013. This period marks the start of the dry season but before significant biomass burning occurs in the region. Median particle number concentrations were 266 cm-3, with size distributions dominated by an accumulation mode of 130-150 nm. During periods of low particle counts, a smaller Aitken mode could also be seen around 80 nm. While the concentrations were similar in magnitude to those seen during the wet season, the size distributions suggest an enhancement in the accumulation mode compared to the wet season, but not yet to the extent seen later in the dry season, when significant biomass burning takes place. Submicron nonrefractory aerosol composition, as measured by an aerosol chemical speciation monitor (ACSM), was dominated by organic material (around 81 %). Aerosol hygroscopicity was probed using measurements from a hygroscopicity tandem differential mobility analyser (HTDMA), and a quasi-monodisperse cloud condensation nuclei counter (CCNc). The hygroscopicity parameter, κ, was found to be low, ranging from 0.12 for Aitken-mode particles to 0.18 for accumulation-mode particles. This was consistent

  20. Radiation sensitizations at DNA-level by chemical and biological agents. Coordinated programme on improvement of radiotherapy of cancer using modifiers of radiosensitivity of cells

    International Nuclear Information System (INIS)

    Radiation sensitization by chemical agents at DNA level is discussed. Procaine, Halothan and Metronidazole showed no significant effect on unscheduled DNA synthesis (UDS) in mouse spleen cells, investigated by autoradiography and no effect on rejoining of DNA single strand breaks after gamma or UV irradiation. Oxyphenbutazon and prednisolone reduced the replicative DNA synthesis in vitro and in vivo but there was only little effect on DNA repair in the in vivo experiments. These two substances showed also a small reduction in poly(ADP-ribose) synthesis (PAR synthesis). 5-methoxypsoralen (5-MOP) and 8-methoxypsoralen (8-MOP) in combination with UV irradiation showed that 5-MOP was more toxic than mutagen, but induced much less DNA crosslinks than 8-MOP. Autoradiographic studies of radiation sensitization by biological agents showed significant inhibition of UDS in Yoshida tumor cells after acute mycoplasma infection in rats. Nucleoid sedimentation studies showed only in the case of Yoshida tumor cells after mycoplasma infection a dramatic effect in the sedimentation behaviour. Sensitization of cells by changing chromatin structure was also studied. Benzamide, 3-NH2-benzamide, 3-Methoxybenzamide, Spermine, Theophyllin and Caffeine were tested in different concentrations on replicative DNA synthesis, UDS after UV irradiation and PAR synthesis Chinese hamster ovary cells. 5-Methoxybenzamide was the strongest sensitizer and inhibitor of the PAR synthesis, and was used in further experiments. Results of KFA Juelich on sensitization of a mamma-adenocarcinoma EO 771 on C57 B1 mice are given. Replicative DNA synthesis, DNA repair and PAR synthesis were compared in spleen cells and adenocarcinoma cells after treatment with 5-Methoxybenzamide. An inhibitory effect on UDS could be shown only in adenocarcinoma cells but not in the mice spleen cells

  1. International media spotlight on the Amazon roams, but rarely enlightens

    Directory of Open Access Journals (Sweden)

    Jeff Tollefson

    2015-07-01

    Full Text Available Abstract The international media has played a powerful role by highlighting problems in the Brazilian Amazon, projecting the views of scientists and activists and projecting data from Brazil’s satellite monitoring program to throughout society. Journalists have also told powerful stories about violence and corruption and put pressure on both the Brazilian government and the agribusiness industry. But very few have attempted to explain the forces at work in the Brazilian Amazon today, despite the fact that the drop in deforestation, if sustained, would represent perhaps a singular environmental success story that could have repercussions across the world. If the goal of the media is to seek and promote understanding in the midst of confusion and debate, journalists must engage on a deeper level.

  2. Atmospheric turbulence within and above an Amazon forest

    CERN Document Server

    Ramos, F M; Sá, L D A; Rosa, R R; Ramos, Fernando M.; Bolzan, Mauricio J. A.; Sa, Leonardo D. A.; Rosa, Reinaldo R.

    2004-01-01

    In this paper, we discuss the impact of a rain forest canopy on the statistical characteristics of atmospheric turbulence. This issue is of particular interest for understanding on how the Amazon terrestrial biosphere interact with the atmosphere. For this, we used a probability density function model of velocity and temperature differences based on Tsallis' non-extensive thermostatistics. We compared theoretical results with experimental data measured in a 66 m micrometeorological tower, during the wet-season campaign of the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA). Particularly, we investigated how the value of the entropic parameter is affected when one moves into the canopy, or when one passes from day/unstable to night/stable conditions. We show that this new approach provides interesting insights on turbulence in a complex environment such as the Amazon forest.

  3. ANALISIS E-BISNIS TERHADAP AMAZON DAN AQUARELLE

    Directory of Open Access Journals (Sweden)

    Agustinna Yosanny

    2010-11-01

    Full Text Available The internet and digital world is one thing that needs to be taken into account by the Company. Business through Internet, known as e-business, is another way to increase the relation between company and customers or prospective customers. Analysis from the view point of customers and the integration of technologies was conducted on 2 examples sites that well known in doing online business but have different history on how it started the e-commerce. They are Amazon and Aquarelle. By comparing the two sites, the characteristics of e-commerce sites could be studied. As a result, there are striking differences between these two sites, where Amazon is more oriented to sales, while Aquarelle more on customer-oriented impact to the design and implementation of their e-business.

  4. Neutrons, radiation and archaeology: a multi analytical case study of incised rim tradition ceramics in Central Amazon

    International Nuclear Information System (INIS)

    This thesis is an interdisciplinary archaeometric study involving archaeological ceramic material from two large archaeological sites in Central Amazon, namely Lago Grande and Osvaldo, on the confluence region of Negro and Solimoes rivers. It was tested a hypothesis about the existence of an exchange network between the former inhabitants of those sites, focusing on material and/or technological exchange. That hypothesis has implications for archaeological theories of human occupation of the pre-colonial Central Amazon, which try to relativise the role of ecological difficulties of the tropical forest as a limiting factor for the emergence of social complexity in the region. The physical-chemical characterization of potsherds and clay samples near the sites was carried out by: instrumental neutron activation analysis (INAA) to determine the elemental chemical composition; electron paramagnetic resonance (EPR) to determine the firing temperature; X-ray diffraction (XRD) to determine the mineralogical composition; and dating by optically stimulated luminescence (OSL). Previous studies showed that Osvaldo and Lago Grande were occupied by people which produced pottery classified in the Manacapuru and Paredao phases, subclasses of the Incised Rim Tradition, around the 5-10th and 7-12th centuries BC, respectively. INAA results were analyzed by multivariate statistical methods, whereby two chemical groups of pottery were defined for each archaeological site. Significant variation in firing temperatures and mineralogical composition were not identified for such groups. By integration of the results with archaeological data, the superposition between pairs of chemical groups was interpreted as a correlate of an ancient exchange network, although it was not possible to define if it existed exclusively between Lago Grande and Osvaldo. On the contrary, it was suggested that Lago Grande participated in a more extensive exchange network by comparison of two chemical groups

  5. Contribution of regional sources to atmospheric methane over the Amazon Basin in 2010 and 2011

    Science.gov (United States)

    Wilson, Chris; Gloor, Manuel; Gatti, Luciana V.; Miller, John B.; Monks, Sarah A.; McNorton, Joey; Bloom, A. Anthony; Basso, Luana S.; Chipperfield, Martyn P.

    2016-03-01

    We present an assessment of methane (CH4) atmospheric concentrations over the Amazon Basin for 2010 and 2011 using a 3-D atmospheric chemical transport model, two wetland emission models, and new observations made during biweekly flights made over four locations within the basin. We attempt to constrain basin-wide CH4 emissions using the observations, and since 2010 was an unusually dry year, we assess the effect of this drought on Amazonian methane emissions. We find that South American emissions contribute up to 150 ppb to concentrations at the sites, mainly originating from within the basin. Our atmospheric model simulations agree reasonably well with measurements at three of the locations (0.28 ≤ r2 ≤ 0.63, mean bias ≤ 9.5 ppb). Attempts to improve the simulated background CH4 concentration through analysis of simulated and observed sulphur hexafluoride concentrations do not improve the model performance, however. Through minimisation of seasonal biases between the simulated and observed atmospheric concentrations, we scale our prior emission inventories to derive total basin-wide methane emissions of 36.5-41.1 Tg(CH4)/yr in 2010 and 31.6-38.8 Tg(CH4)/yr in 2011. These totals suggest that the Amazon contributes significantly (up to 7%) to global CH4 emissions. Our analysis indicates that factors other than precipitation, such as temperature variations or tree mortality, may have affected microbial emission rates. However, given the uncertainty of our emission estimates, we cannot say definitively whether the noncombustion emissions from the region were different in 2010 and 2011, despite contrasting meteorological conditions between the two years.

  6. Kinetics and equilibrium studies on biosorption of cadmium, lead, and nickel ions from aqueous solutions by intact and chemically modified brown algae

    International Nuclear Information System (INIS)

    Research highlights: → The present study deals with the evaluation of biosorptive removal of Cd (II), Ni (II) and Pb (II) ions by both intact and pre-treated brown marine algae: Cystoseira indica, Sargassum glaucescens, Nizimuddinia zanardini and Padina australis treated with formaldehyde (FA), glutaraldehyde (GA), polyethylene imine (PEI), calcium chloride (CaCl2) and hydrochloric acid (HCl). From the results obtained, chemically modification leads to higher capacity of biosorption. → The equilibrium experimental data were tested using the most common isotherms. The results are best fitted by the Freundlich model among two-parameter models and the Toth, Khan and Radke-Prausnitz models among three-parameter isotherm models for Cd (II), Ni (II) and Pb (II), respectively. → One-way ANOVA and one sample t-tests were performed on experimental data to evaluate the statistical significance of biosorption capacities after five cycles of sorption and desorption. → The kinetic data were fitted by models including pseudo-first-order and pseudo-second-order. From the results obtained, the pseudo-second-order kinetic model describes best the biosorption of cadmium, nickel and lead ions. - Abstract: The present study deals with the evaluation of biosorptive removal of Cd (II), Ni (II) and Pb (II) ions by both intact and pre-treated brown marine algae: Cystoseira indica, Sargassum glaucescens, Nizimuddinia zanardini and Padina australis treated with formaldehyde (FA), glutaraldehyde (GA), polyethylene imine (PEI), calcium chloride (CaCl2) and hydrochloric acid (HCl). Batch shaking adsorption experiments were performed in order to examine the effects of pH, contact time, biomass concentration, biomass treatment and initial metal concentration on the removal process. The optimum sorption conditions for each heavy metal are presented. One-way ANOVA and one sample t-tests were performed on experimental data to evaluate the statistical significance of biosorption capacities

  7. Kinetics and equilibrium studies on biosorption of cadmium, lead, and nickel ions from aqueous solutions by intact and chemically modified brown algae

    Energy Technology Data Exchange (ETDEWEB)

    Montazer-Rahmati, Mohammad Mehdi, E-mail: mrahmati@ut.ac.ir [School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box: 11155-4563, Tehran 4563 (Iran, Islamic Republic of); Rabbani, Parisa; Abdolali, Atefeh [School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box: 11155-4563, Tehran 4563 (Iran, Islamic Republic of); Keshtkar, Ali Reza [Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of)

    2011-01-15

    Research highlights: {yields} The present study deals with the evaluation of biosorptive removal of Cd (II), Ni (II) and Pb (II) ions by both intact and pre-treated brown marine algae: Cystoseira indica, Sargassum glaucescens, Nizimuddinia zanardini and Padina australis treated with formaldehyde (FA), glutaraldehyde (GA), polyethylene imine (PEI), calcium chloride (CaCl{sub 2}) and hydrochloric acid (HCl). From the results obtained, chemically modification leads to higher capacity of biosorption. {yields} The equilibrium experimental data were tested using the most common isotherms. The results are best fitted by the Freundlich model among two-parameter models and the Toth, Khan and Radke-Prausnitz models among three-parameter isotherm models for Cd (II), Ni (II) and Pb (II), respectively. {yields} One-way ANOVA and one sample t-tests were performed on experimental data to evaluate the statistical significance of biosorption capacities after five cycles of sorption and desorption. {yields} The kinetic data were fitted by models including pseudo-first-order and pseudo-second-order. From the results obtained, the pseudo-second-order kinetic model describes best the biosorption of cadmium, nickel and lead ions. - Abstract: The present study deals with the evaluation of biosorptive removal of Cd (II), Ni (II) and Pb (II) ions by both intact and pre-treated brown marine algae: Cystoseira indica, Sargassum glaucescens, Nizimuddinia zanardini and Padina australis treated with formaldehyde (FA), glutaraldehyde (GA), polyethylene imine (PEI), calcium chloride (CaCl{sub 2}) and hydrochloric acid (HCl). Batch shaking adsorption experiments were performed in order to examine the effects of pH, contact time, biomass concentration, biomass treatment and initial metal concentration on the removal process. The optimum sorption conditions for each heavy metal are presented. One-way ANOVA and one sample t-tests were performed on experimental data to evaluate the statistical

  8. Predictive Modelling of Contagious Deforestation in the Brazilian Amazon

    OpenAIRE

    Rosa, Isabel M. D.; Drew Purves; Carlos Souza; Ewers, Robert M.

    2013-01-01

    Tropical forests are diminishing in extent due primarily to the rapid expansion of agriculture, but the future magnitude and geographical distribution of future tropical deforestation is uncertain. Here, we introduce a dynamic and spatially-explicit model of deforestation that predicts the potential magnitude and spatial pattern of Amazon deforestation. Our model differs from previous models in three ways: (1) it is probabilistic and quantifies uncertainty around predictions and parameters; (...

  9. Clay mineral composition of river sediments in the Amazon Basin

    OpenAIRE

    Guyot, Jean-Loup; Jouanneau, J.M.; Soares, L; Boaventura, G.R.; Maillet, N; Lagane, Christelle

    2007-01-01

    Clay minerals are important in evaluating the maturity of suspended sediments, weathering intensity and source area. However, there are processes that can change the mineral assemblage such as river transportation, deposition, remobilization and tributary inputs. In terms of water discharge and sediment yield, the Amazon is one of the largest rivers in the world. Most of the suspended sediments come from the Andes, crossing the lowlands before reaching the ocean. This study measures the spati...

  10. Amazon surveillance system (SIVAM): U.S. and Brazilian cooperation

    OpenAIRE

    Wittkoff, E. Peter

    1999-01-01

    Approved for public release; distribution is unlimited The thesis will demonstrate bow Brazil's System for Surveillance of the Amazon (SIVAM) increases bilateral linkages in Brazilian-U.S. relations within the framework of the international relations theory of complex interdependence; The thesis's central theme is that SIVAM might benefit U.S. national security interests in Latin America, especially in counter-drug operations. For example, an opportunity for greater cooperation between the...

  11. Reserves protect against deforestation fires in the Amazon.

    Directory of Open Access Journals (Sweden)

    J Marion Adeney

    Full Text Available BACKGROUND: Reserves are the principal means to conserve forests and biodiversity, but the question of whether reserves work is still debated. In the Amazon, fires are closely linked to deforestation, and thus can be used as a proxy for reserve effectiveness in protecting forest cover. We ask whether reserves in the Brazilian Amazon provide effective protection against deforestation and consequently fires, whether that protection is because of their location or their legal status, and whether some reserve types are more effective than others. METHODOLOGY/PRINCIPAL FINDINGS: Previous work has shown that most Amazonian fires occur close to roads and are more frequent in El Niño years. We quantified these relationships for reserves and unprotected areas by examining satellite-detected hot pixels regressed against road distance across the entire Brazilian Amazon and for a decade with 2 El Niño-related droughts. Deforestation fires, as measured by hot pixels, declined exponentially with increasing distance from roads in all areas. Fewer deforestation fires occurred within protected areas than outside and the difference between protected and unprotected areas was greatest near roads. Thus, reserves were especially effective at preventing these fires where they are known to be most likely to burn; but they did not provide absolute protection. Even within reserves, at a given distance from roads, there were more deforestation fires in regions with high human impact than in those with low impact. The effect of El Niño on deforestation fires was greatest outside of reserves and near roads. Indigenous reserves, limited-use reserves, and fully protected reserves all had fewer fires than outside areas and did not appear to differ in their effectiveness. CONCLUSIONS/SIGNIFICANCE: Taking time, regional factors, and climate into account, our results show that reserves are an effective tool for curbing destructive burning in the Amazon.

  12. Climate change, deforestation and the fate of Amazon

    Directory of Open Access Journals (Sweden)

    Alberti G

    2008-03-01

    Full Text Available Climate change, deforestation and the fate of Amazon. Understanding and mitigation the impact of the increasing population and global economic activities on tropical forests is one of the greatest challenges for scientists and policy makers. A summary of some of the latest findings and thinking on this topic has been reported by Malhi and colleagues in a recent paper published on Science. An overview and comments on this paper is herein proposed.

  13. Does Land Tenure Insecurity Drive Deforestation in the Brazilian Amazon?

    OpenAIRE

    Claudio ARAUJO; Araujo Bonjean, Catherine; Combes, Jean-Louis; Combes Motel, Pascale; Eustaquio J. REIS

    2011-01-01

    The purpose of this paper is to highlight the detrimental impact of land tenure insecurity on deforestation in the Brazilian Amazon. It is related to recent controversies about the detrimental impact of land laws on deforestation, which seem to legitimize land encroachments. The latter is mainly the result of land tenure insecurity which is a key characteristic of this region and results from a long history of interactions between rural social unrest and land reforms or land laws. A simple mo...

  14. Climate change, deforestation and the fate of Amazon

    OpenAIRE

    Alberti G

    2008-01-01

    Climate change, deforestation and the fate of Amazon. Understanding and mitigation the impact of the increasing population and global economic activities on tropical forests is one of the greatest challenges for scientists and policy makers. A summary of some of the latest findings and thinking on this topic has been reported by Malhi and colleagues in a recent paper published on Science. An overview and comments on this paper is herein proposed.

  15. Naming and Shaming for Conservation: Evidence from the Brazilian Amazon

    OpenAIRE

    Elías Cisneros; Sophie Lian Zhou; Jan Börner

    2015-01-01

    Deforestation in the Brazilian Amazon has dropped substantially after a peak of over 27 thousand square kilometers in 2004. Starting in 2008, the Brazilian Ministry of the Environment has regularly published blacklists of critical districts with high annual forest loss. Farms in blacklisted districts face additional administrative hurdles to obtain authorization for clearing forests. In this paper we add to the existing literature on evaluating the Brazilian anti-deforestation policies by spe...

  16. Property rights and deforestation in the Brazilian Amazon

    OpenAIRE

    Claudio ARAUJO; Araujo Bonjean, Catherine; Combes, Jean-Louis; Combes Motel, Pascale; Eustaquio J. REIS

    2011-01-01

    This paper focuses on the impact of property rights insecurity on deforestation in the Brazilian Legal Amazon. Deforestation is considered as a risk management strategy: property rights insecurity reduces the present value of forests and fosters forest conversion into agricultural and pasture lands. Moreover, deforestation is the consequence of strategic interactions between landowners and squatters. Landowners clear the forest preventively in order to assert the productive use of land and to...

  17. SUGAR CANE EXPANSION: DOES IT CONTRIBUTE TO AMAZON DEFORESTATION?

    OpenAIRE

    Castro, Eduardo Rodrigues de; Teixeira, Erly Cardoso; Valdes, Constanza

    2012-01-01

    The aim of this study is to investigate the direct and indirect impacts of sugarcane expansion on deforestation in the Brazilian Amazon from 2001 to 2008. The analysis is based on the multi-output production theory where the annual agricultural acreage represents the Production Possibility Frontier. It assumes that agricultural area is limited and any agricultural expansion occurs over traditional agricultural areas displacing some crops and pushing them to the agricultural frontier, where fo...

  18. Influence Deforestation on Hydrological Cycle at Amazon Basin

    Science.gov (United States)

    Cohen, J. C.; Beltrao, J.; Gandu, A. W.

    2007-05-01

    The last three decades, the Amazon Basin has been affected for the occupation with consequence large deforestation. The principal area deforested is located from Maranhao state to Rondonia state. This area is common called "Arc Deforestation", and representing the transition between two important Brazilian ecosystems, Amazon Forest and Savanna Region. Theses ecosystems have precious biodiversity, and it has population about 10.331.000. The objective of this work was to evaluate the impact of arc deforestation on the hydrological cycle at Amazon basin, using BRAMS (Brazilian developments on the Regional Atmospheric Modeling System) including a model of dynamic vegetation, called GEMTM (General Energy and Mass Transport Model). In this study, numerical simulations were performed with a high spatial resolution regional model that allows capture some mesoscale aspects associated to the land used, topography, coastlines and large rivers. In order to predict the impact of the arc deforestation over the hydrological cycle, it was run two model simulations, conducted over a one-year period. In the first simulation, designated "control", it was used the scenarios derived from Soares Filho (2002), for the year 2002, in governance situation. In the second simulation called "deforestation", it was used the scenarios for the 2050, derived from results of Soares-Filho with governance, too. The higher-resolution regional modeling revealed important features of the deforestation process, displaying some associated mesoscale effects that are not typically represented in similar Global Circulation Model simulations. Near coastal zones and along large rivers, deforestation resulted in reduced precipitation. However, it was predicted increased precipitation over mountainous areas, especially on mountain slopes facing river valleys. Then, these higher-resolution simulations showed that, in general, orography, coastline profile and large river distribution play important roles in

  19. On indigeneity, change, and representation in the northeastern Ecuadorian Amazon

    OpenAIRE

    Gabriela Valdivia

    2005-01-01

    Neoliberal reforms throughout Latin America are intended to promote development by opening up economies and encouraging market-oriented practices. These reforms have deeply affected the lives of indigenous peoples and their relationship with extralocal actors. Today, in the Ecuadorian Amazon, some indigenous peoples participate in oil-extraction negotiations, tourism, and intensive cattle ranching and agriculture as part of increased market integration. In the midst of these changes, question...

  20. Cropland expansion changes deforestation dynamics in the southern Brazilian Amazon

    OpenAIRE

    Douglas C. Morton; DeFries, Ruth S.; Shimabukuro, Yosio E.; Liana O. Anderson; ARAI Egidio; del Bon Espirito-Santo, Fernando; Freitas, Ramon; Morisette, Jeff

    2006-01-01

    Intensive mechanized agriculture in the Brazilian Amazon grew by >3.6 million hectares (ha) during 2001–2004. Whether this cropland expansion resulted from intensified use of land previously cleared for cattle ranching or new deforestation has not been quantified and has major implications for future deforestation dynamics, carbon fluxes, forest fragmentation, and other ecosystem services. We combine deforestation maps, field surveys, and satellite-based information on vegetation phenology to...

  1. On the sources of hydrological prediction uncertainty in the Amazon

    OpenAIRE

    R. C. D. Paiva; Collischonn, W.; Bonnet, M.P.; L. G. G. de Gonçalves

    2012-01-01

    Recent extreme events in the Amazon River basin and the vulnerability of local population motivate the development of hydrological forecast systems (HFSs) using process based models for this region. In this direction, the knowledge of the source of errors in HFSs may guide the choice on improving model structure, model forcings or developing data assimilation (DA) systems for estimation of initial model states. We evaluate the relative importance of hydrologic initial conditions (ICs) an...

  2. Land inequality and deforestation in the Brazilian Amazon

    OpenAIRE

    Albuquerque Sant'Anna, André

    2012-01-01

    The aim of this paper is to demonstrate the relationship between land inequality and deforestation in the Brazilian Amazon. Therefore, it is developed an occupational choice model where an individual decides whether to become a farmer in an already established place or to move in search of economic opportunities and land to clear at the agricultural frontier. This model provides theoretical predictions that are tested empirically. Based on data from 515 municipalities, this paper estimates a ...

  3. Contrasting Strategies of Tree Function in a Seasonal Amazon Rainforest

    Science.gov (United States)

    Ivanov, V. Y.; Oliveira, R.; Agee, E.; Brum, M., Jr.; Saleska, S. R.; Fatichi, S.; Ewing, G.

    2015-12-01

    The increased frequency and severity of drought conditions in the Amazon Basin region have emphasized the question of rainforest vulnerability and resilience to heat and drought-induced stresses. However, what emerges from much research is that the impacts of droughts, essential controlling factors of the rainforest function, and variability of tree-scale strategies are yet to be fully understood. We present here a preliminary analysis of hydraulic relations of a seasonal Amazon rainforest using a set of ecohydrologic data collected through the GoAmazon project over dry and wet seasons. Expressions of different hydraulic strategies are identified that convey different implications for tree resilience during short- (diurnal) and longer-term (seasonal) stress periods. These hydraulic strategies appear to be inter-related with the tree growth and non-structural carbohydrate dynamics, contributing to the understanding of trait coordination at the whole-plant scale. Integration of individual responses is conducted over a range of wood density and exposure conditions. The results of this research thus shed light on the implication of variations in the rainforest function for future stresses, vital for predictive models of ecosystem dynamics of next generation.

  4. Large-scale Modeling of Inundation in the Amazon Basin

    Science.gov (United States)

    Luo, X.; Li, H. Y.; Getirana, A.; Leung, L. R.; Tesfa, T. K.

    2015-12-01

    Flood events have impacts on the exchange of energy, water and trace gases between land and atmosphere, hence potentially affecting the climate. The Amazon River basin is the world's largest river basin. Seasonal floods occur in the Amazon Basin each year. The basin being characterized by flat gradients, backwater effects are evident in the river dynamics. This factor, together with large uncertainties in river hydraulic geometry, surface topography and other datasets, contribute to difficulties in simulating flooding processes over this basin. We have developed a large-scale inundation scheme in the framework of the Model for Scale Adaptive River Transport (MOSART) river routing model. Both the kinematic wave and the diffusion wave routing methods are implemented in the model. A new process-based algorithm is designed to represent river channel - floodplain interactions. Uncertainties in the input datasets are partly addressed through model calibration. We will present the comparison of simulated results against satellite and in situ observations and analysis to understand factors that influence inundation processes in the Amazon Basin.

  5. Oil frontiers and indigenous resistance in the Peruvian Amazon

    Energy Technology Data Exchange (ETDEWEB)

    Orta-Martinez, Marti [ICTA, Universitat Autonoma de Barcelona, 08193 Barcelona (Spain); Finer, Matt [Save America' s Forests, 4 Library Court. NW, Washington DC 20003 (United States)

    2010-12-15

    The Peruvian Amazon is culturally and biologically one of the most diverse regions on Earth. Since the 1920s oil exploration and extraction in the region have threatened both biodiversity and indigenous peoples, particularly those living in voluntary isolation. We argue that the phenomenon of peak oil, combined with rising demand and consumption, is now pushing oil extraction into the most remote corners of the world. Modern patterns of production and consumption and high oil prices are forcing a new oil exploratory boom in the Peruvian Amazon. While conflicts spread on indigenous territories, new forms of resistance appear and indigenous political organizations are born and become more powerful. The impacts of oil exploration and exploitation and indigenous resistance throughout the oil history of the Peruvian Amazon are reviewed here, focusing on the Achuar people in Rio Corrientes. The driving forces, impacts, and responses to the current oil exploration boom are analyzed from an environmental justice perspective. We conclude that, in a context of peak oil and growing global demand for oil, such devastating effects for minor quantities of oil are likely to increase and impact other remote parts of the world. (author)

  6. Deforestation, floodplain dynamics, and carbon biogeochemistry in the Amazon Basin

    Science.gov (United States)

    Bryan, M. L.; Dunne, T.; Richey, J.; Melack, J.; Simonett, D. S.; Woodwell, G.

    1984-01-01

    Three aspects of the physical geographic environment of the Amazon Basin are considered: (1) deforestation and reforestation, (2) floodplain dynamics, and (3) fluvial geomorphology. Three independent projects are coupled in this experiment to improve the in-place research and to ensure that the Shuttle Imaging Radar-B (SIR-B) experiment stands on a secure base of ongoing work. Major benefits to be obtained center on: (1) areal and locational information, (2) data from various depression angles, and (3) digital radar signatures. Analysis will be conducted for selected sites to define how well SIR-B data can be used for: (1) definition of extent and location of deforestation in a tropical moist forest, (2) definition and quantification of the nature of the vegetation and edaphic conditions on the (floodplain) of the Amazon River, and (3) quantification of the accuracy with which the geometry and channel shifting of the Amazon River may be mapped using SIR-B imagery in conjunction with other remote sensing data.

  7. North Tropical Atlantic influence on western Amazon fire season variability

    Science.gov (United States)

    Fernandes, Katia; Baethgen, Walter; Bernardes, Sergio; DeFries, Ruth; DeWitt, David G.; Goddard, Lisa; Lavado, Waldo; Lee, Dong Eun; Padoch, Christine; Pinedo-Vasquez, Miguel; Uriarte, Maria

    2011-06-01

    The prevailing wet climate in the western Amazon is not favorable to the natural occurrence of fires. Nevertheless, the current process of clearing of humid forests for agriculture and cattle ranching has increased the vulnerability of the region to the spread of fires. Using meteorological stations precipitation and the Moderate Resolution Spectroradiometer (MODIS) Active-Fires (AF) during 2000-2009, we show that fire anomalies vary closely with July-August-September (JAS) precipitation variability as measured by the Standardized Precipitation Index (SPI). The precipitation variability is, in turn, greatly determined by sea surface temperature (SST) anomalies in the North Tropical Atlantic (NTA). We develop a linear regression model to relate local fire activity to an index of the NTA-SST. By using seasonal forecasts of SST from a coupled model, we are able to predict anomalous JAS fire activity as early as April. We applied the method to predict the severe 2010 JAS season, which indicated strongly positive seasonal fire anomalies within the 95% prediction confidence intervals in most western Amazon. The spatial distribution of predicted SPI was also in accordance with observed precipitation anomalies. This three months lead time precipitation and fire prediction product in the western Amazon could help local decision makers to establish an early warning systems or other appropriate course of action before the fire season begins.

  8. Artisanal fisheries of the Xingu River basin in Brazilian Amazon.

    Science.gov (United States)

    Isaac, V J; Almeida, M C; Cruz, R E A; Nunes, L G

    2015-08-01

    The present study characterises the commercial fisheries of the basin of the Xingu River, a major tributary of the Amazon River, between the towns of Gurupá (at the mouth of the Amazon) and São Félix do Xingu. Between April, 2012, and March, 2014, a total of 23,939 fishing trips were recorded, yielding a total production of 1,484 tons of fish, harvested by almost three thousand fishers. The analysis of the catches emphasizes the small-scale and artisanal nature of the region's fisheries, with emphasis on the contribution of the motorised canoes powered by "long-tail" outboard motors. Larger motorboats operate only at the mouth of the Xingu and on the Amazon. Peacock bass (Cichla spp.), croakers (Plagioscion spp.), pacu (a group containing numerous serrasalmid species), aracu (various anostomids), and curimatã (Prochilodus nigricans) together contributed more than 60% of the total catch. Mean catch per unit effort was 18 kg/fisher-1.day-1, which varied among fishing methods (type of vessel and fishing equipment used), river sections, and time of the year. In most cases, yields varied little between years (2012 and 2013). The technical database provided by this study constitutes an important resource for the regulation of the region's fisheries, as well as for the evaluation of future changes resulting from the construction of the Belo Monte dam on the Xingu River.

  9. Ballast water: a threat to the Amazon Basin.

    Science.gov (United States)

    Pereira, Newton Narciso; Botter, Rui Carlos; Folena, Rafael Dompieri; Pereira, José Pinheiro Fragoso Neto; da Cunha, Alan Cavalcanti

    2014-07-15

    Ballast water exchange (BWE) is the most efficient measure to control the invasion of exotic species from ships. This procedure is being used for merchant ships in national and international voyages. The ballast water (BW) salinity is the main parameter to evaluate the efficacy of the mid-ocean ballast water exchange. The vessels must report to the Port State Control (PSC), via ballast water report (BWR), where and how the mid-ocean BWE was performed. This measure allows the PSC to analyze this information before the ship arrives at the port, and to decide whether or not it should berth. Ship BW reporting forms were collected from the Captaincy of Santana and some ships were visited near the Port of Santana, located in Macapá (Amazon River), to evaluate the BW quality onboard. We evaluated data submitted in these BWR forms and concluded that the BWE efficacy might be compromised, because data contained in these BWR indicate that some ships did not change their BW. We found mistakes in filling the BWR forms and lack of information. Moreover, these ships had discharged BW with high level of salinity, Escherichia coli and total coliforms into the Amazon River. We concluded that the authorities of the Amazon Region need to develop more efficient proceedings to evaluate the ballast water reporting forms and BW quality, as there is potential risk of future invasion of exotic species in Brazilian ports.

  10. Estimation of the evapotranspiration in the Amazon Basin

    International Nuclear Information System (INIS)

    The establishment of a water balance for the Amazon Basin constitutes a problem of difficult solution, not only on the account of its extension and characteristics, but also for lack of sufficient meteorological and hydrological data. In an attempt to estimate the magnitude of the main components of the water balance, a study was made with data from the Brazilian Amazon Region and from some observation stations in other countries. An energy balance was made and based on this balance the water balance of the region was established, having the Penman method been adapted to forest conditions. The data obtained indicate that 90% of the evaportranspiration is due to the energy balance. The evaportranspiration in this area should be very close to the potential evaportranspiration, and the average found was of the order of 4mm/day, i.e., 1460mm/year. As a first approximation it was found that the Amazon Basin system receives 14,4X1012m3 water/year through precipitation, this total being balanced by a surface discharge of 5,5 x1012m3 /year and an evaportranspiration of 8,9x1012m3/year. Since transpiration by plants represents 61,8% of the water balance, all seems to indicate that intensive deforestation shall bring about alterations of the hydrological cycle

  11. Use of filter papers to determine seroprevalence of Toxoplasma gondii among hunted ungulates in remote Peruvian Amazon.

    Science.gov (United States)

    Aston, Emily J; Mayor, Pedro; Bowman, Dwight D; Mohammed, Hussni O; Liotta, Janice L; Kwok, Oliver; Dubey, J P

    2014-04-01

    Toxoplasmosis is a zoonosis caused by the protozoan Toxoplasma gondii, and it is found worldwide. To determine whether ungulates are reservoirs of T. gondii in an isolated and remote region of the northeastern Peruvian Amazon, antibodies to T. gondii were determined in 5 species of ungulates by the modified agglutination test (MAT). These animals were hunted by subsistence hunters along the Yavarí-Mirín River, in the northeastern Peruvian Amazon. Blood samples were collected by hunters on filter papers. For determination of T. gondii antibodies, blood was eluted from filter papers, and a titer of 1:25 was considered indicative of exposure to T. gondii. Antibodies to T. gondii were found in 26 (31.0%) peccaries (Pecari tajacu, Tayassu pecari), six (17.1%) brocket deer (Mazama americana, Mazama gouazoubira), and four (40.0%) lowland tapir (Tapirus terrestris). We also introduced a modification to the MAT protocol that allows the extraction of fluid samples from several types of laboratory-grade filter paper, thus enabling researchers to easily adapt their approaches to the materials presented to them.

  12. Observations and Modeling of the Green Ocean Amazon 2014/15. Nanoparticle Size Distribution (NPSD) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Kuang, C [Brookhaven National Lab. (BNL), Upton, NY (United States); Artaxo, P [University of Sao Paulo (Brazil); Martin, S [Harvard Univ., Cambridge, MA (United States); Wang, J [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-04-01

    Aerosol nucleation and initial growth were investigated during the Green Ocean Amazon (GoAmazon) 2014/15 campaign. Aerosol sampling occurred during the wet and dry seasons of 2014, and took place at the T3 measurement site, downwind of the city of Manaus, Brazil. Characterization of the aerosol size distribution from 10 to 500 nm was accomplished through the deployment of a conventional Scanning Mobility Particle Spectrometer (SMPS) and a fine condensation particle counter (> 10 nm). In order to directly measure aerosol nucleation and initial growth, a Nano SMPS (1.5-20 nm) was also deployed, consisting of a condensation particle counter-based electrical mobility spectrometer that was modified for the detection of sub-3 nm aerosol. Measurements of the aerosol size distribution from 1.5 nm to 10 nm were obtained during the first observational period, and from 3 nm to 15 nm during the second observational period. Routine, stable measurement in this size range was complicated due to persistent water condensation in the Nano SMPS and diffusional transport losses

  13. Methane emissions from floodplains in the Amazon Basin: challenges in developing a process-based model for global applications

    Science.gov (United States)

    Ringeval, B.; Houweling, S.; van Bodegom, P. M.; Spahni, R.; van Beek, R.; Joos, F.; Röckmann, T.

    2014-03-01

    Tropical wetlands are estimated to represent about 50% of the natural wetland methane (CH4) emissions and explain a large fraction of the observed CH4 variability on timescales ranging from glacial-interglacial cycles to the currently observed year-to-year variability. Despite their importance, however, tropical wetlands are poorly represented in global models aiming to predict global CH4 emissions. This publication documents a first step in the development of a process-based model of CH4 emissions from tropical floodplains for global applications. For this purpose, the LPX-Bern Dynamic Global Vegetation Model (LPX hereafter) was slightly modified to represent floodplain hydrology, vegetation and associated CH4 emissions. The extent of tropical floodplains was prescribed using output from the spatially explicit hydrology model PCR-GLOBWB. We introduced new plant functional types (PFTs) that explicitly represent floodplain vegetation. The PFT parameterizations were evaluated against available remote-sensing data sets (GLC2000 land cover and MODIS Net Primary Productivity). Simulated CH4 flux densities were evaluated against field observations and regional flux inventories. Simulated CH4 emissions at Amazon Basin scale were compared to model simulations performed in the WETCHIMP intercomparison project. We found that LPX reproduces the average magnitude of observed net CH4 flux densities for the Amazon Basin. However, the model does not reproduce the variability between sites or between years within a site. Unfortunately, site information is too limited to attest or disprove some model features. At the Amazon Basin scale, our results underline the large uncertainty in the magnitude of wetland CH4 emissions. Sensitivity analyses gave insights into the main drivers of floodplain CH4 emission and their associated uncertainties. In particular, uncertainties in floodplain extent (i.e., difference between GLC2000 and PCR-GLOBWB output) modulate the simulated emissions by a

  14. Could the STARS detect deforestation in the Brazilian Amazon?

    Science.gov (United States)

    Mello, M. P.; Trabaquini, K.; Rudorff, B. F.; Oliveira, J. C.

    2013-05-01

    The Brazilian National Institute for Space Research (INPE) has been monitoring the Brazilian Legal Amazon deforestation through the PRODES project since 1988, providing yearly deforestation maps based on about 60 m spatial resolution. Additionally, INPE's Real Time Deforestation Detection System (DETER) has monthly indicating, based on high temporal resolution satellite data, where and when the forest is being felled. However, those monitoring processes are mainly based on visual interpretation, which is accurate but a hard and time consuming task. The Spectral-Temporal Analysis by Response Surface (STARS), which synthesizes the full information content of a multitemporal-multispectral remote sensing image dataset to represent the spectral variation over time of features on the Earth's surface, comes as an alternative for applications in land cover change detection, such as deforestation in the Brazilian Amazon. Thus, since deforestation process presents particular spectral changes over time, spectral-temporal response surfaces could be fitted to describe its change patterns, allowing to detect deforested areas. In this context, this work aims to apply the STARS to detect deforestation in the Brazilian Amazon, using Landsat-5 multitemporal-multispectral images. Four georeferenced images covering about 3.400 square kilometres within the Mato Grosso State, Brazil (13°17'S; 55°50'W to 14°20'S; 55°10'W) were used: one Multispectral Scanner (MSS) image from 1980 (bands 4, 5, 6 and 7 - 60 m spatial resolution); and three Thematic Mapper (TM) images from 1990, 2000 and 2010 (bands 1, 2, 3, 4, 5 and 7 - 30 m spatial resolution). The MSS image was resampled to 30 m to match the TM spatial resolution. All images were then used as input for STARS resulting in a Multi-Coefficient Image (MCI) with 10 synthetic bands formed by the 10 fitted coefficients of a Polynomial Trend Surface (PTS) model with degree equal to three. The MCI was used as input for a decision tree (DT

  15. Election-driven weakening of deforestation control in the Brazilian Amazon

    NARCIS (Netherlands)

    Rodrigues-Filho, S.; Verburg, R.W.; Lindoso, D.; Debortoli, N.; Bursztyn, M.; Vilhena, A.M.G.

    2015-01-01

    Commodity prices, exchange rate, infrastructural projects and migration patterns are known and important drivers of Amazon deforestation, but cannot solely explain the high rates observed in 1995 and 2003–2004 in six Brazilian Amazon states. Deforestation predictions using those widely applied drive

  16. Vibrio cholerae O1 from superficial water of the Tucunduba Stream, Brazilian Amazon

    OpenAIRE

    Sá, L.L.C.; Vale, E.R.V.; Garza, D.R.; A.C.P. Vicente

    2012-01-01

    Isolation and genetic characterization of an environmental Vibrio cholerae O1 from the Amazon is reported. This strain lacks two major virulence factors - CTX and TCP - but carries other genes related to virulence. Genetic similarity with epidemic strains is evaluated and the importance of V. cholerae surveillance in the Amazon is emphasized.

  17. Effects of environmental change on malaria in the Amazon region of Brazil

    NARCIS (Netherlands)

    Takken, W.; Tarso Vilarinhos, de P.; Schneider, P.; Santos, dos F.

    2003-01-01

    Malaria is endemic in Brazil, affecting mostly the Amazon states. Whereas 50 years ago good progress was made towards its control, since the opening up of the Amazon region for forestry, agriculture and livestock activities, the disease has rapidly increased in incidence, peaking to >500,000 case

  18. Transforming Data: An Ethnography of Scientific Data from the Brazilian Amazon

    DEFF Research Database (Denmark)

    Walford, Antonia Caitlin

    This thesis is an ethnography of scientific data produced by a Brazil-led scientific project in the Brazilian Amazon. It describes how the researchers and technicians make data about the Amazon forest, and how this data in turn generates different scientific communities, scientific subjectivities...

  19. Election-driven weakening of deforestation control in the Brazilian Amazon.

    NARCIS (Netherlands)

    Rodrigues-Filho, S; Verburg, R.W.; Bursztyn, M; Lindoso, D; Debortoli, N

    2015-01-01

    Commodity prices, exchange rate, infrastructural projects and migration patterns are known and important drivers of Amazon deforestation, but cannot solely explain the high rates observed in 1995 and 2003–2004 in six Brazilian Amazon states. Deforestation predictions using those widely applied drive

  20. Atmospheric correction analysis on LANDSAT data over the Amazon region. [Manaus, Brazil

    Science.gov (United States)

    Parada, N. D. J. (Principal Investigator); Dias, L. A. V.; Dossantos, J. R.; Formaggio, A. R.

    1983-01-01

    The Amazon Region natural resources were studied in two ways and compared. A LANDSAT scene and its attributes were selected, and a maximum likelihood classification was made. The scene was atmospherically corrected, taking into account Amazonic peculiarities revealed by (ground truth) of the same area, and the subsequent classification. Comparison shows that the classification improves with the atmospherically corrected images.