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Sample records for chemically correct natural

  1. Chemical and natural stressors combined:

    DEFF Research Database (Denmark)

    Gergs, André; Zenker, Armin; Grimm, Volker

    2013-01-01

    In addition to natural stressors, populations are increasingly exposed to chemical pollutants released into the environment. We experimentally demonstrate the loss of resilience for Daphnia magna populations that are exposed to a combination of natural and chemical stressors even though effects...... vulnerability to the toxicant which acts in a size selective manner. Moreover, population vulnerability to the toxicant increases with predator size and predation intensity whereas indirect trait-mediated interactions via predator kairomones may buffer chemical effects to a certain extent. Our study...

  2. Natural products in chemical biology

    National Research Council Canada - National Science Library

    Civjan, Natanya

    2012-01-01

    .... The book begins by introducing natural products from different origins, moves on to presenting and discussing biosynthesis of various classes of natural products, and then looks at natural products...

  3. Perceptual adaptation to the correction of natural astigmatism.

    Directory of Open Access Journals (Sweden)

    Maria Vinas

    Full Text Available The visual system adjusts to changes in the environment, as well as to changes within the observer, adapting continuously to maintain a match between visual coding and visual environment. We evaluated whether the perception of oriented blur is biased by the native astigmatism, and studied the time course of the after-effects following spectacle correction of astigmatism in habitually non-corrected astigmats.We tested potential shifts of the perceptual judgments of blur orientation in 21 subjects. The psychophysical test consisted on a single interval orientation identification task in order to measure the perceived isotropic point (astigmatism level for which the image did not appear oriented to the subject from images artificially blurred with constant blur strength (B=1.5 D, while modifying the orientation of the blur according to the axis of natural astigmatism of the subjects. Measurements were performed after neutral (gray field adaptation on naked eyes under full correction of low and high order aberrations. Longitudinal measurements (up to 6 months were performed in three groups of subjects: non-astigmats and corrected and uncorrected astigmats. Uncorrected astigmats were provided with proper astigmatic correction immediately after the first session. Non-astigmats did not show significant bias in their perceived neutral point, while in astigmatic subjects the perceived neutral point was significantly biased, typically towards their axis of natural astigmatism. Previously uncorrected astigmats shifted significantly their perceived neutral point towards more isotropic images shortly (2 hours after astigmatic correction wear, and, once stabilized, remained constant after 6 months. The shift of the perceived neutral point after correction of astigmatism was highly correlated with the amount of natural astigmatism.Non-corrected astigmats appear to be naturally adapted to their astigmatism, and astigmatic correction significantly changes their

  4. Chemical osmosis in natural clayey materials

    NARCIS (Netherlands)

    Keijzer, T.J.S.

    2000-01-01

    Semipenneable properties of clayey natural materials can have a significant impact on a range of geological and geochemical processes on laboratory and field scale. The importance of chemical osmosis in semipenneable natural clays for transport of contaminants was first discussed in the

  5. Developing Formal Correctness Properties from Natural Language Requirements

    Science.gov (United States)

    Nikora, Allen P.

    2006-01-01

    This viewgraph presentation reviews the rationale of the program to transform natural language specifications into formal notation.Specifically, automate generation of Linear Temporal Logic (LTL)correctness properties from natural language temporal specifications. There are several reasons for this approach (1) Model-based techniques becoming more widely accepted, (2) Analytical verification techniques (e.g., model checking, theorem proving) significantly more effective at detecting types of specification design errors (e.g., race conditions, deadlock) than manual inspection, (3) Many requirements still written in natural language, which results in a high learning curve for specification languages, associated tools and increased schedule and budget pressure on projects reduce training opportunities for engineers, and (4) Formulation of correctness properties for system models can be a difficult problem. This has relevance to NASA in that it would simplify development of formal correctness properties, lead to more widespread use of model-based specification, design techniques, assist in earlier identification of defects and reduce residual defect content for space mission software systems. The presentation also discusses: potential applications, accomplishments and/or technological transfer potential and the next steps.

  6. Chemical and Biological Significance of Naturally Occurring ...

    African Journals Online (AJOL)

    PROF HORSFALL

    and www.bioline.org.br/j a. Chemical and Biological Significance of Naturally Occurring Additives on. African Black Soap and its Performance. IKOTUN, A. ADEBOMI; OGUNDELE, O. FISAYO; KAYODE, O. MOBOLAJI;. *AJAELU, C. JOHN. Department of Chemistry and Industrial Chemistry, Bowen Univeristy, Iwo, Nigeria.

  7. Nature-Inspired Chemical Reaction Optimisation Algorithms.

    Science.gov (United States)

    Siddique, Nazmul; Adeli, Hojjat

    2017-01-01

    Nature-inspired meta-heuristic algorithms have dominated the scientific literature in the areas of machine learning and cognitive computing paradigm in the last three decades. Chemical reaction optimisation (CRO) is a population-based meta-heuristic algorithm based on the principles of chemical reaction. A chemical reaction is seen as a process of transforming the reactants (or molecules) through a sequence of reactions into products. This process of transformation is implemented in the CRO algorithm to solve optimisation problems. This article starts with an overview of the chemical reactions and how it is applied to the optimisation problem. A review of CRO and its variants is presented in the paper. Guidelines from the literature on the effective choice of CRO parameters for solution of optimisation problems are summarised.

  8. Sequence correction of random coil chemical shifts: correlation between neighbor correction factors and changes in the Ramachandran distribution

    DEFF Research Database (Denmark)

    Kjærgaard, Magnus; Poulsen, Flemming Martin

    2011-01-01

    . The contributions from the neighboring residues are typically removed by using neighbor correction factors determined based on each residue's effect on glycine chemical shifts. Due to its unusual conformational freedom, glycine may be particularly unrepresentative for the remaining residue types. In this study, we......Random coil chemical shifts are necessary for secondary chemical shift analysis, which is the main NMR method for identification of secondary structure in proteins. One of the largest challenges in the determination of random coil chemical shifts is accounting for the effect of neighboring residues...... use random coil peptides containing glutamine instead of glycine to determine the random coil chemical shifts and the neighbor correction factors. The resulting correction factors correlate to changes in the populations of the major wells in the Ramachandran plot, which demonstrates that changes...

  9. Physical and chemical investigations on natural dyes

    Science.gov (United States)

    Acquaviva, S.; D'Anna, E.; de Giorgi, M. L.; Della Patria, A.; Baraldi, P.

    2010-09-01

    Natural dyes have been used extensively in the past for many purposes, such us to colour fibers and to produce inks, watercolours and paints, but their use declined rapidly after the discovery of synthetic colours. Nowadays we witness a renewed interest, as natural dyes are neither toxic nor polluting. In this work, physical and chemical properties of four selected dyes, namely red (Madder), yellow (Weld and Turmeric) and blue (Woad) colours, produced by means of traditional techniques at the Museo dei Colori Naturali (Lamoli, Italy), have been investigated. The chromatic properties have been studied through the reflectance spectroscopy, a non-invasive technique for the characterisation of chromaticity. Reflection spectra both from powders and egg-yolk tempera models have been acquired to provide the typical features of the dyes in the UV-vis spectral range. Moreover, to assess the feasibility of laser cleaning procedures, tempera layers were investigated after irradiation with an excimer laser. Micro Raman spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-Ray analyses have complemented the survey, returning compositional and morphological information as well. Efforts have been made to give scientific feedback to the production processes and to support the research activity in the restoration of the artworks where these dyes were employed.

  10. Physical, chemical and microbiological changes during natural ...

    African Journals Online (AJOL)

    Gowé is a traditional Beninese fermented beverage prepared from sprouted and non- prouted cereals. Due to urbanization, a new technique without any malting step has appeared in Southern Benin and is now widely used. The two techniques were compared using sorghum as the raw material. The physical, chemical and ...

  11. Chemical inhibition of NAT10 corrects defects of laminopathic cells

    Science.gov (United States)

    Larrieu, Delphine; Britton, Sébastien; Demir, Mukerrem; Rodriguez, Raphaël; Jackson, Stephen P.

    2014-01-01

    Downregulation and mutations of the nuclear-architecture proteins Lamin A and C cause misshapen nuclei and altered chromatin organization associated with cancer and laminopathies, including the premature-aging disease Hutchinson-Gilford progeria syndrome (HGPS). Here, we identified the small molecule “Remodelin” that improved nuclear architecture, chromatin organization and fitness of both human Lamin A/C depleted cells and HGPS-derived patient cells, and decreased markers of DNA damage in these cells. Using a combination of chemical, cellular and genetic approaches, we identified the acetyl-transferase protein NAT10 as the target of Remodelin that mediated nuclear shape rescue in laminopathic cells via microtubule reorganization. These findings provide insights into how NAT10 affects nuclear architecture, and suggest alternative strategies for treating laminopathies and aging. PMID:24786082

  12. [Analysis of tongue color under natural daylight based on chromatic aberration correction].

    Science.gov (United States)

    Xu, Jia-tuo; Zhang, Zhi-feng; Yan, Zhu-juan; Tu, Li-ping; Lu, Lu-ming; Shi, Mei-yu; Zhu, Feng-lan

    2009-05-01

    To establish an analytical method for tongue image acquisition under natural daylight based on L*a*b* error correction, and to observe the classification rules of tongue color using color error correction. The tongue images in 413 cases were collected under natural indoor daylight by using Nikon D70 digital SLR camera, and then the color error was adjusted by using Nikon Capture NX software correction according to Kodak Q-13 grey card. The classification and quantitative analysis of the tongue color after software correction was carried out depending on L*a*b* color space. The software correction method had good effects in adjusting the tongue color image error. The L* values of light red, deep red and cyanosis tongues decreased as compared with that of light white tongue (PL*a*b* error correction is accurate in color restoration and feasible to operate.

  13. Chemical Biology of Microbial Anticancer Natural Products

    DEFF Research Database (Denmark)

    Bladt, Tanja Thorskov; Gotfredsen, Charlotte Held

    with activity towards CLL cells in vitro. We based our screening on a combined analytical and bio-guided approach of LC-DADHRMS based dereplication, explorative solid-phase-extraction (E-SPE), and a co-culture platform of CLL and stromal cells. The activity was tracked to single compounds in seven of the most...... than 100 years. New natural products (NPs) are continually discovered and with the increase in selective biological assays, previously described compounds often also display novel bioactivities, justifying their presence in novel screening efforts. Screening and discovery of compounds with activity...... active extracts in a screening setup including 289 fungal extracts. The novel ophiobolin U was isolated together with the known ophiobolin C, H, K as well as 6-epiophiobolin G, K and N from three fungal strains in the Aspergillus section Usti, and further ophiobolins were bought from commercial sources...

  14. Natural evidence for chemical and early biological evolution

    Science.gov (United States)

    Kvenvolden, K. A.

    1974-01-01

    Oparin (1924) and Haldane (1929) have independently hypothesized that life arose under reducing conditions through an evolutionary sequence of events involving increasingly complex organic substances. The natural evidence for this hypothesis of chemical evolution is considered, giving particular attention to tangible samples which have been chemically analyzed in earth-bound laboratories. It is found that meteorites provide naturally occurring evidence in support of chemical evolution, but not of biological evolution. Studies on the early Precambrian Swaziland Sequence and the Bulawayan System of southern Africa provide evidence for very early biological evolution.

  15. Linking neuroethology to the chemical biology of natural products

    DEFF Research Database (Denmark)

    Olivera, Baldomero M.; Raghuraman, Shrinivasan; Schmidt, Eric W.

    2017-01-01

    From a biological perspective, a natural product can be defined as a compound evolved by an organism for chemical interactions with another organism including prey, predator, competitor, pathogen, symbiont or host. Natural products hold tremendous potential as drug leads and have been extensively...

  16. Chemical osmosis in natural clayey materials. Geologica Ultraiectina (196)

    NARCIS (Netherlands)

    Keijzer, T.J.S.

    2000-01-01

    Semipenneable properties of clayey natural materials can have a significant impact on a range of geological and geochemical processes on laboratory and field scale. The importance of chemical osmosis in semipenneable natural clays for transport of contaminants was first discussed in the Netherlands

  17. The thermodynamic natural path in chemical reaction kinetics

    Directory of Open Access Journals (Sweden)

    Moishe garfinkle

    2000-01-01

    Full Text Available The Natural Path approach to chemical reaction kinetics was developed to bridge the considerable gap between the Mass Action mechanistic approach and the non-mechanistic irreversible thermodynamic approach. The Natural Path approach can correlate empirical kinetic data with a high degree precision, as least equal to that achievable by the Mass-Action rate equations, but without recourse mechanistic considerations. The reaction velocities arising from the particular rate equation chosen by kineticists to best represent the kinetic behavior of a chemical reaction are the natural outcome of the Natural Path approach. Moreover, by virtue of its thermodynamic roots, equilibrium thermodynamic functions can be extracted from reaction kinetic data with considerable accuracy. These results support the intrinsic validity of the Natural Path approach.

  18. A temperature error correction method for a naturally ventilated radiation shield

    Science.gov (United States)

    Yang, Jie; Liu, Qingquan; Dai, Wei; Ding, Rrenhui

    2016-11-01

    Due to solar radiation exposure, air flowing inside a naturally ventilated radiation shield may produce a measurement error of 0.8 °C or higher. To improve the air temperature observation accuracy, a temperature error correction method is proposed. The correction method is based on a Computational Fluid Dynamics (CFD) method and a Genetic Algorithm (GA) method. The CFD method is implemented to analyze and calculate the temperature errors of a naturally ventilated radiation shield under various environmental conditions. Then, a temperature error correction equation is obtained by fitting the CFD results using the GA method. To verify the performance of the correction equation, the naturally ventilated radiation shield and an aspirated temperature measurement platform are characterized in the same environment to conduct the intercomparison. The aspirated temperature measurement platform serves as an air temperature reference. The mean temperature error given by measurements is 0.36 °C, and the mean temperature error given by correction equation is 0.34 °C. This correction equation allows the temperature error to be reduced by approximately 95%. The mean absolute error (MAE) and the root mean square error (RMSE) between the temperature errors given by the correction equation and the temperature errors given by the measurements are 0.07 °C and 0.08 °C, respectively.

  19. Unilateral zygomatic hypoplasia correction by L-shaped zygomatic osteotomy with natural coral.

    Science.gov (United States)

    Su, Ruowei; Gui, Lai; Liu, Jianfeng; Niu, Feng; Chen, Ying; Wang, Meng

    2015-05-01

    Zygomatic osteotomy is a common method of zygomatic hypoplasia correction. Natural coral is considered to be a good bone substitute. Few studies on unilateral zygomatic hypoplasia correction by zygomatic osteotomy with natural coral have been reported. This study was performed to evaluate the clinical morphological results and surgical outcomes of unilateral zygomatic hypoplasia correction by L-shaped zygomatic osteotomy with natural coral. From 1996 to 2012, a total of 42 patients with hypoplastic zygomas treated by L-shaped zygomatic osteotomy with natural coral were included in this study. Based on facial analysis results and x-ray and CT measurements, the degradation of natural coral, new bone formation, and clinical outcomes were observed and recorded. All surgical procedures achieved satisfactory results without complications. During the stabilization period of about 12 to 15 months, all natural coral blocks were completely degraded and replaced by new bone. Good mechanical strength and continuity of the new bone and good zygomatic asymmetry were achieved in each patient. No recurrence was observed during the follow-up period. L-shaped zygomatic osteotomy with natural coral is an effective method of unilateral zygomatic hypoplasia correction.

  20. Study and interpretation of the chemical characteristics of natural water

    Science.gov (United States)

    Hem, John David

    1985-01-01

    The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from human activities. Broad interrelationships among these processes and their effects can be discerned by application of principles of chemical thermodynamics. Some of the processes of solution or precipitation of minerals can be closely evaluated by means of principles of chemical equilibrium, including the law of mass action and the Nernst equation. Other processes are irreversible and require consideration of reaction mechanisms and rates. The chemical composition of the crustal rocks of the Earth and the composition of the ocean and the atmosphere are significant in evaluating sources of solutes in natural freshwater.

  1. Novel Principles and Techniques to Create a Natural Design in Female Hairline Correction Surgery.

    Science.gov (United States)

    Park, Jae Hyun

    2015-12-01

    Female hairline correction surgery is becoming increasingly popular. However, no guidelines or methods of female hairline design have been introduced to date. The purpose of this study was to create an initial framework based on the novel principles of female hairline design and then use artistic ability and experience to fine tune this framework. An understanding of the concept of 5 areas (frontal area, frontotemporal recess area, temporal peak, infratemple area, and sideburns) and 5 points (C, A, B, T, and S) is required for female hairline correction surgery (the 5A5P principle). The general concepts of female hairline correction surgery and natural design methods are, herein, explained with a focus on the correlations between these 5 areas and 5 points. A natural and aesthetic female hairline can be created with application of the above-mentioned concepts. The 5A5P principle of forming the female hairline is very useful in female hairline correction surgery.

  2. "Human Nature": Chemical Engineering Students' Ideas about Human Relationships with the Natural World

    Science.gov (United States)

    Goldman, Daphne; Assaraf, Orit Ben-Zvi; Shemesh, Julia

    2014-01-01

    While importance of environmental ethics, as a component of sustainable development, in preparing engineers is widely acknowledged, little research has addressed chemical engineers' environmental concerns. This study aimed to address this void by exploring chemical engineering students' values regarding human-nature relationships. The study was…

  3. Chemical nature of catalysts of oxide nanoparticles in environment ...

    Indian Academy of Sciences (India)

    DOI 10.1007/s12034-016-1308-6. Chemical nature of catalysts of oxide nanoparticles in environment prevailing during growth of carbon nanostructures by CCVD. M JANA1,∗, ASIL1 and S RAY1,2. 1Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247 667, India.

  4. Study and interpretation of the chemical characteristics of natural water

    Science.gov (United States)

    Hem, John David

    1970-01-01

    The chemical composition of natural water is derived from many different sources of solutes, including gases and aerosols from the atmosphere, weathering and erosion of rocks and soil, solution or precipitation reactions occurring below the land surface, and cultural effects resulting from activities of man. Some of the processes of solution or precipitation of minerals can be closely evaluated by means of principles of chemical equilibrium including the law of mass action and the Nernst equation. Other processes are irreversible and require consideration of reaction mechanisms and rates. The chemical composition of the crustal rocks of the earth and the composition of the ocean and the atmosphere are significant in evaluating sources of solutes in natural fresh water.

  5. Two-Way Chemical Communication between Artificial and Natural Cells

    Science.gov (United States)

    2017-01-01

    Artificial cells capable of both sensing and sending chemical messages to bacteria have yet to be built. Here we show that artificial cells that are able to sense and synthesize quorum signaling molecules can chemically communicate with V. fischeri, V. harveyi, E. coli, and P. aeruginosa. Activity was assessed by fluorescence, luminescence, RT-qPCR, and RNA-seq. Two potential applications for this technology were demonstrated. First, the extent to which artificial cells could imitate natural cells was quantified by a type of cellular Turing test. Artificial cells capable of sensing and in response synthesizing and releasing N-3-(oxohexanoyl)homoserine lactone showed a high degree of likeness to natural V. fischeri under specific test conditions. Second, artificial cells that sensed V. fischeri and in response degraded a quorum signaling molecule of P. aeruginosa (N-(3-oxododecanoyl)homoserine lactone) were constructed, laying the foundation for future technologies that control complex networks of natural cells. PMID:28280778

  6. Two-Way Chemical Communication between Artificial and Natural Cells.

    Science.gov (United States)

    Lentini, Roberta; Martín, Noël Yeh; Forlin, Michele; Belmonte, Luca; Fontana, Jason; Cornella, Michele; Martini, Laura; Tamburini, Sabrina; Bentley, William E; Jousson, Olivier; Mansy, Sheref S

    2017-02-22

    Artificial cells capable of both sensing and sending chemical messages to bacteria have yet to be built. Here we show that artificial cells that are able to sense and synthesize quorum signaling molecules can chemically communicate with V. fischeri, V. harveyi, E. coli, and P. aeruginosa. Activity was assessed by fluorescence, luminescence, RT-qPCR, and RNA-seq. Two potential applications for this technology were demonstrated. First, the extent to which artificial cells could imitate natural cells was quantified by a type of cellular Turing test. Artificial cells capable of sensing and in response synthesizing and releasing N-3-(oxohexanoyl)homoserine lactone showed a high degree of likeness to natural V. fischeri under specific test conditions. Second, artificial cells that sensed V. fischeri and in response degraded a quorum signaling molecule of P. aeruginosa (N-(3-oxododecanoyl)homoserine lactone) were constructed, laying the foundation for future technologies that control complex networks of natural cells.

  7. Correction of MS data for naturally occurring isotopes in isotope labelling experiments.

    Science.gov (United States)

    Millard, Pierre; Letisse, Fabien; Sokol, Serguei; Portais, Jean-Charles

    2014-01-01

    Mass spectrometry (MS) in combination with isotope labelling experiments is widely used for investigations of metabolism and other biological processes. Quantitative applications-e.g., (13)C metabolic flux analysis-require correction of raw MS data (isotopic clusters) for the contribution of all naturally abundant isotopes. This chapter describes how to perform such correction using the software IsoCor. This flexible, user-friendly software can be used to exploit any isotopic tracer, from well-known ((13)C, (15)N, (18)O, etc.) to unusual ((57)Fe, (77)Se, etc.) isotopes. It also provides options-e.g., correction for the isotopic purity of the tracer-to improve the accuracy of quantitative isotopic studies, and allows automated correction of large datasets that can be collected with modern MS methods.

  8. Correction

    CERN Multimedia

    2002-01-01

    The photo on the second page of the Bulletin n°48/2002, from 25 November 2002, illustrating the article «Spanish Visit to CERN» was published with a wrong caption. We would like to apologise for this mistake and so publish it again with the correct caption.   The Spanish delegation, accompanied by Spanish scientists at CERN, also visited the LHC superconducting magnet test hall (photo). From left to right: Felix Rodriguez Mateos of CERN LHC Division, Josep Piqué i Camps, Spanish Minister of Science and Technology, César Dopazo, Director-General of CIEMAT (Spanish Research Centre for Energy, Environment and Technology), Juan Antonio Rubio, ETT Division Leader at CERN, Manuel Aguilar-Benitez, Spanish Delegate to Council, Manuel Delfino, IT Division Leader at CERN, and Gonzalo León, Secretary-General of Scientific Policy to the Minister.

  9. The nature of chemical bonds from PNOF5 calculations.

    Science.gov (United States)

    Matxain, Jon M; Piris, Mario; Uranga, Jon; Lopez, Xabier; Merino, Gabriel; Ugalde, Jesus M

    2012-06-18

    Natural orbital functional theory (NOFT) is used for the first time in the analysis of different types of chemical bonds. Concretely, the Piris natural orbital functional PNOF5 is used. It provides a localization scheme that yields an orbital picture which agrees very well with the empirical valence shell electron pair repulsion theory (VSEPR) and Bent's rule, as well as with other theoretical pictures provided by valence bond (VB) or linear combination of atomic orbitals-molecular orbital (LCAO-MO) methods. In this context, PNOF5 provides a novel tool for chemical bond analysis. In this work, PNOF5 is applied to selected molecules that have ionic, polar covalent, covalent, multiple (σ and π), 3c-2e, and 3c-4e bonds. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Thermodynamics of natural selection II: Chemical Carnot cycles.

    Science.gov (United States)

    Smith, Eric

    2008-05-21

    This is the second in a series of three papers devoted to energy flow and entropy changes in chemical and biological processes, and to their relations to the thermodynamics of computation. In the first paper of the series, it was shown that a general-form dimensional argument from the second law of thermodynamics captures a number of scaling relations governing growth and development across many domains of life. It was also argued that models of physiology based on reversible transformations provide sensible approximations within which the second-law scaling is realized. This paper provides a formal basis for decomposing general cyclic, fixed-temperature chemical reactions, in terms of the chemical equivalent of Carnot's cycle for heat engines. It is shown that the second law relates the minimal chemical work required to perform a cycle to the Kullback-Leibler divergence produced in its chemical output ensemble from that of a Gibbs equilibrium. Reversible models of physiology are used to create reversible models of natural selection, which relate metabolic energy requirements to information gain under optimal conditions. When dissipation is added to models of selection, the second-law constraint is generalized to a relation between metabolic work and the combined energies of growth and maintenance.

  11. Natural Ores as Oxygen Carriers in Chemical Looping Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Hanjing; Siriwardane, Ranjani; Simonyi, Thomas; Poston, James

    2013-08-01

    Chemical looping combustion (CLC) is a combustion technology that utilizes oxygen from oxygen carriers (OC), such as metal oxides, instead of air to combust fuels. The use of natural minerals as oxygen carriers has advantages, such as lower cost and availability. Eight materials, based on copper or iron oxides, were selected for screening tests of CLC processes using coal and methane as fuels. Thermogravimetric experiments and bench-scale fixed-bed reactor tests were conducted to investigate the oxygen transfer capacity, reaction kinetics, and stability during cyclic reduction/oxidation reaction. Most natural minerals showed lower combustion capacity than pure CuO/Fe{sub 2}O{sub 3} due to low-concentrations of active oxide species in minerals. In coal CLC, chryscolla (Cu-based), magnetite, and limonite (Fe-based) demonstrated better reaction performances than other materials. The addition of steam improved the coal CLC performance when using natural ores because of the steam gasification of coal and the subsequent reaction of gaseous fuels with active oxide species in the natural ores. In methane CLC, chryscolla, hematite, and limonite demonstrated excellent reactivity and stability in 50-cycle thermogravimetric analysis tests. Fe{sub 2}O{sub 3}-based ores possess greater oxygen utilization but require an activation period before achieving full performance in methane CLC. Particle agglomeration issues associated with the application of natural ores in CLC processes were also studied by scanning electron microscopy (SEM).

  12. Atomic-scale chemical imaging of composition and bonding by aberration-corrected microscopy.

    Science.gov (United States)

    Muller, D A; Kourkoutis, L Fitting; Murfitt, M; Song, J H; Hwang, H Y; Silcox, J; Dellby, N; Krivanek, O L

    2008-02-22

    Using a fifth-order aberration-corrected scanning transmission electron microscope, which provides a factor of 100 increase in signal over an uncorrected instrument, we demonstrated two-dimensional elemental and valence-sensitive imaging at atomic resolution by means of electron energy-loss spectroscopy, with acquisition times of well under a minute (for a 4096-pixel image). Applying this method to the study of a La(0.7)Sr(0.3)MnO3/SrTiO3 multilayer, we found an asymmetry between the chemical intermixing on the manganese-titanium and lanthanum-strontium sublattices. The measured changes in the titanium bonding as the local environment changed allowed us to distinguish chemical interdiffusion from imaging artifacts.

  13. Pesticide Chemical Research in Toxicology: Lessons from Nature.

    Science.gov (United States)

    Casida, John E; Durkin, Kathleen A

    2017-01-17

    Pesticide researchers are students of nature, and each new compound and mechanism turns a page in the ever-expanding encyclopedia of life. Pesticides are both probes to learn about life processes and tools for pest management to facilitate food production and enhance health. In contrast to some household and industrial chemicals, pesticides are assumed to be hazardous to health and the environment until proven otherwise. About a thousand current pesticides working by more than 100 different mechanisms have helped understand many processes and coupled events. Pesticide chemical research is a major source of toxicology information on new natural products, novel targets or modes of action, resistance mechanisms, xenobiotic metabolism, selective toxicity, safety evaluations, and recommendations for safe and effective pest management. Target binding site models help define the effect of substituent changes and predict modifications for enhanced potency and safety and circumvention of resistance. The contribution of pesticide chemical research in toxicology is illustrated here with two each of the newer or most important insecticides, herbicides, and fungicides. The insecticides are imidacloprid and chlorantraniliprole acting on the nicotinic acetylcholine receptor and the ryanodine receptor Ca2+ channel, respectively. The herbicides are glyphosate that inhibits aromatic amino acid biosynthesis and mesotrione that prevents plastoquinone and carotenoid formation. The fungicides are azoxystrobin inhibiting the Qo site of the cytochrome bc1 complex and prothioconazole inhibiting the 14α-demethylase in ergosterol biosynthesis. The two target sites involved for each type of pesticide account for 27-40% of worldwide sales for all insecticides, herbicides, and fungicides. In each case, selection for resistance involving a single amino acid change in the binding site or detoxifying enzyme circumvents the pesticide chemists's structure optimization and guarantees survival of the

  14. Chemical short range order and magnetic correction in liquid manganese–gallium zero alloy

    Energy Technology Data Exchange (ETDEWEB)

    Grosdidier, B. [Laboratoire de Chimie Physique – Approche Multi-Echelle des Milieux Complexes, Institut Jean Bariol, Université de Lorraine, Institut de Chimie, Physique et Matériaux, 1 Bd Arago, 57078 Metz Cedex 3 (France); Ben Abdellah, A. [Laboratoire de Chimie Physique – Approche Multi-Echelle des Milieux Complexes, Institut Jean Bariol, Université de Lorraine, Institut de Chimie, Physique et Matériaux, 1 Bd Arago, 57078 Metz Cedex 3 (France); Innovation and Management of Industrial Systems, Abdelmalek Essaadi University, College of Sciences and Techniques of Tangier , P.O. Box 416, Postal code 90000, Tangier (Morocco); Université Internationale de Rabat, Parc Technopolis Rabat-Shore, 11100 Sala El Jadida (Morocco); Osman, S.M., E-mail: osm@squ.edu.om [Physics Department, College of Science, Sultan Qaboos University, P.O. Box 36, Postal Code 123, Al-Khod, Muscat (Oman); Ataati, J. [Innovation and Management of Industrial Systems, Abdelmalek Essaadi University, College of Sciences and Techniques of Tangier, P.O. Box 416, Postal code 90000, Tangier (Morocco); Gasser, J.G. [Laboratoire de Chimie Physique – Approche Multi-Echelle des Milieux Complexes, Institut Jean Bariol, Université de Lorraine, Institut de Chimie, Physique et Matériaux, 1 Bd Arago, 57078 Metz Cedex 3 (France)

    2015-12-15

    The Mn{sub 66}Ga{sub 34} alloy at this particular composition is known to be zero alloy in which the linear combination of the two neutron scattering lengths weighted by the atomic compositions vanish. Thus for this specific concentration, the effect of the partial structure factors S{sub NN} and S{sub NC} is cancelled by a weighted term, which value is zero. Then the measured total structure factor S(q) gives directly the concentration–concentration structure factor S{sub CC}(q). We present here the first experimental results of neutron diffraction on the Mn{sub 66}Ga{sub 34} “null matrix alloy” at 1050 °C. The main peak of the experimental S{sub CC}(q) gives a strong evidence of a hetero-atomic chemical order in this coordinated alloy. This order also appears in real space radial distribution function which is calculated by the Fourier transform of the structure factor. The degree of hetero-coordination is discussed together with other manganese-polyvalent alloys. However manganese also shows abnormal magnetic scattering in the alloy structure factor which must be corrected. This correction gives an experimental information on the mean effective spin of manganese in this liquid alloy. We present the first critical theoretical calculations of the magnetic correction factor in Mn–Ga zero-alloy based on our accurate experimental measurements of S{sub CC}(q).

  15. Using Fuzzy Optimisation Method in Calculation of Charge Burden to Correct the Chemical Composition of Metal Melt

    Directory of Open Access Journals (Sweden)

    E. Ziółkowski

    2007-07-01

    Full Text Available The article describes a mathematical model of an algorithm used in calculation of the charge burden to correct the misadjusted chemical composition of metal melt. The model assumes that the charge materials covered by calculations are characterised by a fuzzy (uncertain chemical composition. The model also assumes different yield of chemical elements from the metal melt and charge materials. The discussion is completed with an example of calculations illustrating practical application of the said algorithm.

  16. `Human nature': Chemical engineering students' ideas about human relationships with the natural world

    Science.gov (United States)

    Goldman, Daphne; Ben-Zvi Assaraf, Orit; Shemesh, Julia

    2014-05-01

    While importance of environmental ethics, as a component of sustainable development, in preparing engineers is widely acknowledged, little research has addressed chemical engineers' environmental concerns. This study aimed to address this void by exploring chemical engineering students' values regarding human-nature relationships. The study was conducted with 247 3rd-4th year chemical engineering students in Israeli Universities. It employed the New Ecological Paradigm (NEP)-questionnaire to which students added written explanations. Quantitative analysis of NEP-scale results shows that the students demonstrated moderately ecocentric orientation. Explanations to the NEP-items reveal diverse, ambivalent ideas regarding the notions embodied in the NEP, strong scientific orientation and reliance on technology for addressing environmental challenges. Endorsing sustainability implies that today's engineers be equipped with an ecological perspective. The capacity of Higher Education to enable engineers to develop dispositions about human-nature interrelationships requires adaptation of curricula towards multidisciplinary, integrative learning addressing social-political-economic-ethical perspectives, and implementing critical-thinking within the socio-scientific issues pedagogical approach.

  17. Conversion chimique du gaz naturel Chemical Conversion of Natural Gas

    Directory of Open Access Journals (Sweden)

    Chaumette P.

    2006-11-01

    Full Text Available Dans cet article sont passés en revue les travaux de recherche et développement et les procédés existants dans le domaine de la conversion chimique du gaz naturel. Les deux voies possibles, conversion directe du méthane et conversion indirecte, via le gaz de synthèse, sont présentées. Tant la préparation d'hydrocarbures utilisables comme carburants, que celle des composés de bases pour la pétrochimie ou la chimie sont évoquées. L'accent est mis sur l'étape clé du développement de chaque procédé qui, selon le produit visé, consiste en la mise au point d'un nouveau système catalytique, en un changement de la technologie du réacteur, ou en la mise au point d'une section fractionnement moins complexe. This article reviews the research and development work and the existing processes in the area of chemical conversion of natural gas. The two possible methods, direct conversion of methane and indirect conversion via synthesis gas, are discussed. The preparation of hydrocarbons that can be used as fuels and the production of building blocks for the petrochemical and chemical industries are both dealt with. The accent is placed on the key step in developing each process. Depending on the target product, this key step consists in working out a new catalytic system, changing reactor technology or engineering a less complex fractionation section.

  18. Natural selection drives chemical resistance of Datura stramonium

    Directory of Open Access Journals (Sweden)

    Adán Miranda-Pérez

    2016-04-01

    Full Text Available Plant resistance to herbivores involves physical and chemical plant traits that prevent or diminish damage by herbivores, and hence may promote coevolutionary arm-races between interacting species. Although Datura stramonium’s concentration of tropane alkaloids is under selection by leaf beetles, it is not known whether chemical defense reduces seed predation by the specialist weevil, Trichobaris soror, and if it is evolving by natural selection. We measured infestation by T. soror as well as the concentration of the plants’ two main tropane alkaloids in 278 D. stramonium plants belonging to 31 populations in central Mexico. We assessed whether the seed predator exerted preferences on the levels of both alkaloids and whether they affect plant fitness. Results show great variation across populations in the concentration of scopolamine and atropine in both leaves and seeds of plants of D. stramonium, as well as in the intensity of infestation and the proportion of infested fruits by T. soror. The concentration of scopolamine in seeds and leaves are negatively associated across populations. We found that scopolamine concentration increases plant fitness. Our major finding was the detection of a positive relationship between the population average concentrations of scopolamine with the selection differentials of scopolamine. Such spatial variation in the direction and intensity of selection on scopolamine may represent a coevolutionary selective mosaic. Our results support the view that variation in the concentration of scopolamine among-populations of D. stramonium in central Mexico is being driven, in part, by selection exerted by T. soror, pointing an adaptive role of tropane alkaloids in this plant species.

  19. Natural selection drives chemical resistance of Datura stramonium.

    Science.gov (United States)

    Miranda-Pérez, Adán; Castillo, Guillermo; Hernández-Cumplido, Johnattan; Valverde, Pedro L; Borbolla, María; Cruz, Laura L; Tapia-López, Rosalinda; Fornoni, Juan; Flores-Ortiz, César M; Núñez-Farfán, Juan

    2016-01-01

    Plant resistance to herbivores involves physical and chemical plant traits that prevent or diminish damage by herbivores, and hence may promote coevolutionary arm-races between interacting species. Although Datura stramonium's concentration of tropane alkaloids is under selection by leaf beetles, it is not known whether chemical defense reduces seed predation by the specialist weevil, Trichobaris soror, and if it is evolving by natural selection. We measured infestation by T. soror as well as the concentration of the plants' two main tropane alkaloids in 278 D. stramonium plants belonging to 31 populations in central Mexico. We assessed whether the seed predator exerted preferences on the levels of both alkaloids and whether they affect plant fitness. Results show great variation across populations in the concentration of scopolamine and atropine in both leaves and seeds of plants of D. stramonium, as well as in the intensity of infestation and the proportion of infested fruits by T. soror. The concentration of scopolamine in seeds and leaves are negatively associated across populations. We found that scopolamine concentration increases plant fitness. Our major finding was the detection of a positive relationship between the population average concentrations of scopolamine with the selection differentials of scopolamine. Such spatial variation in the direction and intensity of selection on scopolamine may represent a coevolutionary selective mosaic. Our results support the view that variation in the concentration of scopolamine among-populations of D. stramonium in central Mexico is being driven, in part, by selection exerted by T. soror, pointing an adaptive role of tropane alkaloids in this plant species.

  20. Exploring the Potential for Using Inexpensive Natural Reagents Extracted from Plants to Teach Chemical Analysis

    Science.gov (United States)

    Hartwell, Supaporn Kradtap

    2012-01-01

    A number of scientific articles report on the use of natural extracts from plants as chemical reagents, where the main objective is to present the scientific applications of those natural plant extracts. The author suggests that natural reagents extracted from plants can be used as alternative low cost tools in teaching chemical analysis,…

  1. Precipitation ensembles conforming to natural variations derived from a regional climate model using a new bias correction scheme

    Science.gov (United States)

    Kim, Kue Bum; Kwon, Hyun-Han; Han, Dawei

    2016-05-01

    This study presents a novel bias correction scheme for regional climate model (RCM) precipitation ensembles. A primary advantage of using model ensembles for climate change impact studies is that the uncertainties associated with the systematic error can be quantified through the ensemble spread. Currently, however, most of the conventional bias correction methods adjust all the ensemble members to one reference observation. As a result, the ensemble spread is degraded during bias correction. Since the observation is only one case of many possible realizations due to the climate natural variability, a successful bias correction scheme should preserve the ensemble spread within the bounds of its natural variability (i.e. sampling uncertainty). To demonstrate a new bias correction scheme conforming to RCM precipitation ensembles, an application to the Thorverton catchment in the south-west of England is presented. For the ensemble, 11 members from the Hadley Centre Regional Climate Model (HadRM3-PPE) data are used and monthly bias correction has been done for the baseline time period from 1961 to 1990. In the typical conventional method, monthly mean precipitation of each of the ensemble members is nearly identical to the observation, i.e. the ensemble spread is removed. In contrast, the proposed method corrects the bias while maintaining the ensemble spread within the natural variability of the observations.

  2. Mechanical properties of uniaxial natural fabric Grewia tilifolia reinforced epoxy based composites: Effects of chemical treatment

    CSIR Research Space (South Africa)

    Jayaramudu, J

    2014-07-01

    Full Text Available The effects of chemical treatment on the mechanical, morphological, and chemical resistance properties of uniaxial natural fabrics, Grewia tilifolia/epoxy composites, were studied. In order to enhance the interfacial bonding between the epoxy matrix...

  3. Correcting Psychotherapists' Blindsidedness: Formal Feedback as a Means of Overcoming the Natural Limitations of Therapists.

    Science.gov (United States)

    Macdonald, James; Mellor-Clark, John

    2015-01-01

    Monitoring of client progress in psychological therapy using formal outcome measures at each session has been shown to increase the effectiveness of treatment. It seems likely that this 'feedback' effect is achieved by enabling therapists to identify clients at risk of treatment failure so that therapists can pay greater attention to client difficulties, which may be hindering therapeutic work. To date, little attention has been given to understanding relevant mechanisms of formal feedback in psychological therapy. In order to understand and maximize the benefits of feedback, it is essential to explore potential mechanisms contributing to this effect. Research in social psychology may help to explain how feedback works. Findings on cognitive biases in the field of social psychology are explored and linked to preliminary findings in the field of psychotherapy research. Research on cognitive biases and expertise is congruent with indications that clinical prediction in psychotherapy is unreliable and that it may be difficult for clinicians to detect errors in their judgement as a result of a lack of clear corrective feedback. This problem is linked to the fact that clinical outcomes occur in a complex 'noisy' environment where prediction is inherently difficult. Formal feedback may derive its benefits from its ability to help correct naturally occurring biases in therapists' assessment of their work. If these biases are seen as normal, but often avoidable if feedback is used, this may pave the way to greater acceptance of formal feedback by clinicians and enhanced outcomes for clients. The use of formal feedback tools can help therapists overcome inevitable limitations in their ability to predict poor response to treatment, enhancing the likelihood of detecting and resolving client difficulties in therapy. Copyright © 2014 John Wiley & Sons, Ltd.

  4. Marked influence of the nature of the chemical bond on CP-violating signature in molecular ions HBr(+) and HI(+).

    Science.gov (United States)

    Ravaine, Boris; Porsev, Sergey G; Derevianko, Andrei

    2005-01-14

    Heavy polar molecules offer a great sensitivity to the electron electric dipole moment (EDM). To guide emerging searches for EDMs with molecular ions, we estimate the EDM-induced energy corrections for hydrogen halide ions HBr(+) and HI(+) in their respective ground X (2)Pi(3/2) states. We find that the energy corrections due to EDM for the two ions differ by an unexpectedly large factor of 15. We demonstrate that a major part of this enhancement is due to a dissimilarity in the nature of the chemical bond for the two ions: the bond that is nearly of ionic character in HBr(+) exhibits predominantly a covalent nature in HI(+). We conclude that because of this enhancement the HI(+) ion may be a potentially competitive candidate for the EDM search.

  5. Considerations of the chemical biology of microbial natural products provide an effective drug discovery strategy.

    Science.gov (United States)

    Choi, Hyukjae; Oh, Dong-Chan

    2015-09-01

    Conventional approaches to natural product drug discovery rely mainly on random searches for bioactive compounds using bioassays. These traditional approaches do not incorporate a chemical biology perspective. Searching for bioactive molecules using a chemical and biological rationale constitutes a powerful search paradigm. Here, the authors review recent examples of the discovery of bioactive natural products based on chemical and biological interactions between hosts and symbionts, and propose this method provides a more effective means of exploring natural chemical diversity and eventually of discovering new drugs.

  6. Quality not Quantity: The Role of Marine Natural Products in Drug Discovery and Reverse Chemical Proteomics

    OpenAIRE

    Piggott, Andrew M.; Peter Karuso

    2005-01-01

    Reverse chemical proteomics combines affinity chromatography with phage display and promises to be a powerful new platform technology for the isolation of natural product receptors, facilitating the drug discovery process by rapidly linking biologically active small molecules to their cellular receptors and the receptors’ genes. In this paper we review chemical proteomics and reverse chemical proteomics and show how these techniques can add value to natural products research. We also rep...

  7. Natural Attenuation of the Persistent Chemical Warfare Agent ...

    Science.gov (United States)

    Report This project studied the influence of temperature on the natural attenuation of VX from five types of porous/permeable materials: unsealed concrete, plywood, rubber escalator handrail, high density polyethylene (HDPE) plastic, and acoustic ceiling tile.

  8. Chemical nature of catalysts of oxide nanoparticles in environment ...

    Indian Academy of Sciences (India)

    Carbon nanostructures (CNS) are often grown using oxide nanoparticles as catalyst in chemical vapour deposition and these oxides are not expected to survive as such during growth. In the present study, the catalysts of cobalt- and nickel oxide-based nanoparticles of sizes varying over a range have been reduced at 575 ...

  9. Effect of natural and chemical insecticides on Hyalopterus pruni and ...

    African Journals Online (AJOL)

    Experiments were carried out to evaluate the effect of water extracts of Fagonia arabica, Salix alba and Anthmis pseudocotula and their mixtures with chemical insecticide (Malathion) on growth of. Hyalopterus pruni and characters of Armeniaca vulgaris plants and their soils. The data revealed that F.arabica extract at 20% ...

  10. Marine Natural Products: Synthesis, Niche Environments, and Chemical Probes

    OpenAIRE

    Sanchez, Laura Margaret

    2012-01-01

    This dissertation describes various aspects of marine natural product chemistry from compound discovery and elucidation to the development of lead scaffolds, and ultimately the use of natural products to probe biological questions. A wide range of techniques are utilized including solid phase peptide synthesis, novel mass spectrometry methods, and vertebrate microbiota to explore the secondary metabolic potential of intestinal flora. In addition to these techniques, various whole cell and bac...

  11. Quality not Quantity: The Role of Marine Natural Products in Drug Discovery and Reverse Chemical Proteomics

    Directory of Open Access Journals (Sweden)

    Andrew M. Piggott

    2005-06-01

    Full Text Available Reverse chemical proteomics combines affinity chromatography with phage display and promises to be a powerful new platform technology for the isolation of natural product receptors, facilitating the drug discovery process by rapidly linking biologically active small molecules to their cellular receptors and the receptors’ genes. In this paper we review chemical proteomics and reverse chemical proteomics and show how these techniques can add value to natural products research. We also report on techniques for the derivatisation of polystyrene microtitre plates with cleavable linkers and marine natural products that can be used in chemical proteomics or reverse chemical proteomics. Specifically, we have derivatised polystyrene with palau’amine and used reverse chemical proteomics to try and isolate the human receptors for this potent anticancer marine drug.

  12. Distillation of natural fatty acids and their chemical derivatives

    Science.gov (United States)

    Well over 1,000 different fatty acids are known which are natural components of fats, oils (triacylglycerols), and other related compounds. These fatty acids can have different alkyl chain lengths, 0-6 carbon-carbon double bonds possessing cis- or trans-geometry, and can contain a variety of functio...

  13. Synthetic Chemicals with Potential for Natural Attenuation (Postprint)

    Science.gov (United States)

    2012-07-01

    purposes of natural attenuation. In contrast, aerobic bacteria able to grow on nitrobenzene, nitrotoluenes , dinitrotoluenes, dinitrobenzene, nitrobenzoates...of the isomeric nitro compounds can be prob- lematic for microbial degradation. For example, the industrial synthesis of polyurethane produces large...September, 1996 (Spain, 1996). • Vinyl chloride • 1 ,2-Dibromoethane • Polychlorinated biphenyls • Nitrobenzene • Nitrotoluenes • Dinitrotoluenes

  14. 76 FR 19096 - National Starch and Chemical Company, Salisbury, Rowan County, North Carolina; Notice of Correction

    Science.gov (United States)

    2011-04-06

    ... AGENCY National Starch and Chemical Company, Salisbury, Rowan County, North Carolina; Notice of... Liability Act (CERCLA), concerning the National Starch and Chemical Company Site located in Salisbury, Rowan..., Mobile County, Alabama. The Site is located in Salisbury, Rowan County, North Carolina. DATES: The Agency...

  15. Comparative analysis of chemical similarity methods for modular natural products with a hypothetical structure enumeration algorithm.

    Science.gov (United States)

    Skinnider, Michael A; Dejong, Chris A; Franczak, Brian C; McNicholas, Paul D; Magarvey, Nathan A

    2017-08-16

    Natural products represent a prominent source of pharmaceutically and industrially important agents. Calculating the chemical similarity of two molecules is a central task in cheminformatics, with applications at multiple stages of the drug discovery pipeline. Quantifying the similarity of natural products is a particularly important problem, as the biological activities of these molecules have been extensively optimized by natural selection. The large and structurally complex scaffolds of natural products distinguish their physical and chemical properties from those of synthetic compounds. However, no analysis of the performance of existing methods for molecular similarity calculation specific to natural products has been reported to date. Here, we present LEMONS, an algorithm for the enumeration of hypothetical modular natural product structures. We leverage this algorithm to conduct a comparative analysis of molecular similarity methods within the unique chemical space occupied by modular natural products using controlled synthetic data, and comprehensively investigate the impact of diverse biosynthetic parameters on similarity search. We additionally investigate a recently described algorithm for natural product retrobiosynthesis and alignment, and find that when rule-based retrobiosynthesis can be applied, this approach outperforms conventional two-dimensional fingerprints, suggesting it may represent a valuable approach for the targeted exploration of natural product chemical space and microbial genome mining. Our open-source algorithm is an extensible method of enumerating hypothetical natural product structures with diverse potential applications in bioinformatics.

  16. Chemically reduced graphene contains inherent metallic impurities present in parent natural and synthetic graphite

    Science.gov (United States)

    Ambrosi, Adriano; Chua, Chun Kiang; Khezri, Bahareh; Sofer, Zdeněk; Webster, Richard D.; Pumera, Martin

    2012-01-01

    Graphene-related materials are in the forefront of nanomaterial research. One of the most common ways to prepare graphenes is to oxidize graphite (natural or synthetic) to graphite oxide and exfoliate it to graphene oxide with consequent chemical reduction to chemically reduced graphene. Here, we show that both natural and synthetic graphite contain a large amount of metallic impurities that persist in the samples of graphite oxide after the oxidative treatment, and chemically reduced graphene after the chemical reduction. We demonstrate that, despite a substantial elimination during the oxidative treatment of graphite samples, a significant amount of impurities associated to the chemically reduced graphene materials still remain and alter their electrochemical properties dramatically. We propose a method for the purification of graphenes based on thermal treatment at 1,000 °C in chlorine atmosphere to reduce the effect of such impurities on the electrochemical properties. Our findings have important implications on the whole field of graphene research. PMID:22826262

  17. Using alternative biological information in stock assessment: condition-corrected natural mortality of Eastern Baltic cod

    DEFF Research Database (Denmark)

    Casini, Michele; Eero, Margit; Carlshamre, Sofia

    2016-01-01

    its survival. We used results from published experimental literature linking cod condition to starvation and mortality, to estimate the annual proportion of cod close to the lethal condition level in the Eastern Baltic cod stock. Thereafter we applied these results to adjust the natural mortality (M...... M = 0.2. This method could be used for adjusting natural mortalities for other cod stocks where changes in condition are observed....

  18. Anemonefishes rely on visual and chemical cues to correctly identify conspecifics

    Science.gov (United States)

    Johnston, Nicole K.; Dixson, Danielle L.

    2017-09-01

    Organisms rely on sensory cues to interpret their environment and make important life-history decisions. Accurate recognition is of particular importance in diverse reef environments. Most evidence on the use of sensory cues focuses on those used in predator avoidance or habitat recognition, with little information on their role in conspecific recognition. Yet conspecific recognition is essential for life-history decisions including settlement, mate choice, and dominance interactions. Using a sensory manipulated tank and a two-chamber choice flume, anemonefish conspecific response was measured in the presence and absence of chemical and/or visual cues. Experiments were then repeated in the presence or absence of two heterospecific species to evaluate whether a heterospecific fish altered the conspecific response. Anemonefishes responded to both the visual and chemical cues of conspecifics, but relied on the combination of the two cues to recognize conspecifics inside the sensory manipulated tank. These results contrast previous studies focusing on predator detection where anemonefishes were found to compensate for the loss of one sensory cue (chemical) by utilizing a second cue (visual). This lack of sensory compensation may impact the ability of anemonefishes to acclimate to changing reef environments in the future.

  19. Purification process of natural graphite as anode for Li-ion batteries: chemical versus thermal

    Science.gov (United States)

    Zaghib, K.; Song, X.; Guerfi, A.; Rioux, R.; Kinoshita, K.

    The intercalation of Li ions in natural graphite that was purified by chemical and thermal processes was investigated. A new chemical process was developed that involved a mixed aqueous solution containing 30% H 2SO 4 and 30% NH xF y heated to 90 °C. The results of this process are compared to those obtained by heating the natural graphite from 1500 to 2400 °C in an inert environment (thermal process). The first-cycle coulombic efficiency of the purified natural graphite obtained by the chemical process is 91 and 84% after the thermal process at 2400 °C. Grinding the natural graphite before or after purification had no significant effect on electrochemical performance at low currents. However, grinding to a very small particle size before purification permitted optimization of the size distribution of the particles, which gives rise to a more homogenous electrode. The impurities in the graphite play a role as microabrasion agents during grinding which enhances its hardness and improves its mechanical properties. Grinding also modifies the particle morphology from a 2- to a 3-D structure (similar in shape to a potato). This potato-shaped natural graphite shows high reversible capacity at high current densities (about 90% at 1 C rate). Our analysis suggests that thermal processing is considerably more expensive than the chemical process to obtain purified natural graphite.

  20. Natural repair mechanisms in correcting pathogenic mutations in inherited skin disorders

    NARCIS (Netherlands)

    Jonkman, MF; Nuijts, MC; van Essen, AJ

    2003-01-01

    This review assesses molecular aspects of the rescue of disease-causing mutations in genodermatoses by means of naturally occurring secondary genetic phenomena. Such data have important implications for the design of gene therapy approaches for inherited skin diseases. Reversal of the phenotype

  1. 27 CFR 24.182 - Use of acid to correct natural deficiencies.

    Science.gov (United States)

    2010-04-01

    ... AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Production of Wine § 24.182 Use of acid to... natural deficiencies except that in the production of grape wine, tartaric acid may be used to reduce the... citric acid may be added to citrus fruit, juice or wine, only malic acid may be added to apples, apple...

  2. Correction to: Compositional Changes in Foliage Phenolics with Plant Age, a Natural Experiment in Boreal Forests.

    Science.gov (United States)

    Wam, Hilde Karine; Stolter, Caroline; Nybakken, Line

    2017-10-13

    The article Compositional Changes in Foliage Phenolics with Plant Age, a Natural Experiment in Boreal Forests, written by Hilde Karine Wam, Caroline Stolter and Line Nybakken, was originally published electronically on the publisher's internet portal (currently SpringerLink) on August 29, 2017 without open access.

  3. 'Ancient episteme' and the nature of fossils: a correction of a modern scholarly error.

    Science.gov (United States)

    Jordan, J M

    2016-04-01

    Beginning the nineteenth-century and continuing down to the present, many authors writing on the history of geology and paleontology have attributed the theory that fossils were inorganic formations produced within the earth, rather than by the deposition of living organisms, to the ancient Greeks and Romans. Some have even gone so far as to claim this was the consensus view in the classical period up through the Middle Ages. In fact, such a notion was entirely foreign to ancient and medieval thought and only appeared within the manifold of 'Renaissance episteme,' the characteristics of which have often been projected backwards by some historians onto earlier periods. This paper endeavors to correct this error, explain the development of the Renaissance view, describe certain ancient precedents thereof, and trace the history of the misinterpretation in the literature.

  4. Behavioral and chemical ecology of ants (Hymenoptera, Formicidae) and their natural enemies in dynamic coffee agroecosystems.

    OpenAIRE

    Mathis, Kaitlyn A.

    2015-01-01

    Social insects rank among the most ubiquitous and ecologically dominant terrestrial animals on Earth. Complex communication and social organization are two defining features of social insect societies and ants, in particular, have evolved extensive systems of chemical communication. In both natural and agricultural systems, including coffee agroecosystems, ants are important predators and often have strong and complex effects on pest species. In this dissertation, I explore how chemical comm...

  5. Natural and active chemical remediation of toxic metals, organics, and radionuclides in the aquatic environment

    Energy Technology Data Exchange (ETDEWEB)

    McPherson, G.; Pintauro, P.; O`Connor, S. [and others

    1996-05-02

    This project focuses on the chemical aspects of remediation, with the underlying theme that chemical remediation does occur naturally. Included are studies on the fate of heavy metal and organic contaminants discharged into aquatic environments; accurate assay metal contaminants partitioned into soils, water and tissue; development of novel polymeric membranes and microporous solids for the entrapment of heavy metals; and the development of hybrid chemo-enzymatic oxidative schemes for aromatics decontamination. 49 refs.

  6. The Effect of Natural and Chemical Compounds on Rooting Traits of Bougainvillea (Bougainvillea spectabilis L.

    Directory of Open Access Journals (Sweden)

    Mehran Fathi

    2017-09-01

    Full Text Available Bougainvillea (Bougainvillea spectabilis L. is an evergreen, difficult-to-root ornamental plant with plentiful applications in green spaces. One of the effective methods in plants propagation is the use of hormonal compounds such as indole butyric acid. Despite the positive effects of these hormones on rooting process, their chemical nature causing environmental risks. Thus, the use of alternative natural compounds with favorable influence to create environmental health and living creatures is important. This experiment was conducted to examine the impact of natural carbohydrate compounds and chemical hormonal compounds on the rooting traits of bougainvillea in the research greenhouse of Gorgan Agricultural Research Center and in the Horticulture Laboratory of Department of Plant Production, Gorgan University of Agriculture Science and Natural Resources, Iran in 2015-2016. The study was based on a Completely Randomized Design with six treatments (indole butyric acid (IBA, aspirin pills, LD pills, natural honey, grape syrup, and gum Arabic, each at four rates, and a control with five replications, each one including five cuttings. The natural and chemical treatments influenced rooting traits including rooting percentage, the number of primary and secondary roots, primary root length, root fresh and dry weight, and survival rate of the cuttings significantly at the 1% level. The treatments of 4000 ppm IBA and 10% grape syrup exhibited significant differences with other studied treatments, control, and displayed the best quantity and quality of the rooting. However, 20% gum Arabic and honey, 4 pills L-1 (320 mg L-1 aspirin, and 4 pills L-1 (0.72 mg L-1 LD were related to the best rooting of the cuttings as compared to other treatments and control. Given the effectiveness of natural compounds like grape syrup on the rooting of bougainvillea cuttings, because of the natural and non-chemical nature, their cost-effectiveness, organic and friendly

  7. Systems metabolic engineering of microorganisms for natural and non-natural chemicals.

    Science.gov (United States)

    Lee, Jeong Wook; Na, Dokyun; Park, Jong Myoung; Lee, Joungmin; Choi, Sol; Lee, Sang Yup

    2012-05-17

    Growing concerns over limited fossil resources and associated environmental problems are motivating the development of sustainable processes for the production of chemicals, fuels and materials from renewable resources. Metabolic engineering is a key enabling technology for transforming microorganisms into efficient cell factories for these compounds. Systems metabolic engineering, which incorporates the concepts and techniques of systems biology, synthetic biology and evolutionary engineering at the systems level, offers a conceptual and technological framework to speed the creation of new metabolic enzymes and pathways or the modification of existing pathways for the optimal production of desired products. Here we discuss the general strategies of systems metabolic engineering and examples of its application and offer insights as to when and how each of the different strategies should be used. Finally, we highlight the limitations and challenges to be overcome for the systems metabolic engineering of microorganisms at more advanced levels.

  8. Treatment of Actual Chemical Wastewater by a Heterogeneous Fenton Process Using Natural Pyrite

    OpenAIRE

    Liang Sun; Yan Li; Aimin Li

    2015-01-01

    Wastewater from chemical plants has remarkable antibiotic effects on the microorganisms in traditional biological treatment processes. An enhanced Fenton system catalyzed by natural pyrite was developed to degrade this kind of wastewater. Approximately 30% chemical oxygen demand (COD) was removed within 120 min when 50 mmol/L H2O2 and 10 g/L natural pyrite were used at initial pH from 1.8 to 7. A BOD5/COD enhancement efficiency of 210% and an acute biotoxicity removal efficiency of 84% were a...

  9. A new algorithm for least-cost path analysis by correcting digital elevation models of natural landscapes

    Science.gov (United States)

    Baek, Jieun; Choi, Yosoon

    2017-04-01

    Most algorithms for least-cost path analysis usually calculate the slope gradient between the source cell and the adjacent cells to reflect the weights for terrain slope into the calculation of travel costs. However, these algorithms have limitations that they cannot analyze the least-cost path between two cells when obstacle cells with very high or low terrain elevation exist between the source cell and the target cell. This study presents a new algorithm for least-cost path analysis by correcting digital elevation models of natural landscapes to find possible paths satisfying the constraint of maximum or minimum slope gradient. The new algorithm calculates the slope gradient between the center cell and non-adjacent cells using the concept of extended move-sets. If the algorithm finds possible paths between the center cell and non-adjacent cells with satisfying the constraint of slope condition, terrain elevation of obstacle cells existing between two cells is corrected from the digital elevation model. After calculating the cumulative travel costs to the destination by reflecting the weight of the difference between the original and corrected elevations, the algorithm analyzes the least-cost path. The results of applying the proposed algorithm to the synthetic data sets and the real-world data sets provide proof that the new algorithm can provide more accurate least-cost paths than other conventional algorithms implemented in commercial GIS software such as ArcGIS.

  10. T1-corrected fat quantification using chemical shift-based water/fat separation: application to skeletal muscle

    Science.gov (United States)

    Karampinos, Dimitrios C.; Yu, Huzanzhou; Shimakawa, Ann; Link, Thomas M.; Majumdar, Sharmila

    2011-01-01

    Chemical shift based water/fat separation, like iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL), has been proposed for quantifying intermuscular adipose tissue (IMAT). An important confounding factor in IDEAL-based IMAT quantification is the large difference in T1 between muscle and fat, which can cause significant overestimation in the fat fraction. This T1 bias effect is usually reduced by employing small flip angles. T1-correction can be performed by employing at least two different flip angles and fitting for T1 of water and fat. In the present work, a novel approach for the water/fat separation problem in a dual flip angle experiment is introduced and a new approach for the selection of the two flip angles, labeled as the unequal small flip angle approach, is developed, aiming to improve the noise efficiency of the T1-correction step relative to existing approaches. It is shown that the use of flip angles, selected such the muscle water signal is assumed to be T1-independent for the first flip angle and the fat signal is assumed to be T1-independent for the second flip angle, has superior noise performance to the use of equal small flip angles (no T1 estimation required) and the use of large flip angles (T1 estimation required). PMID:21452279

  11. Neural processing, perception, and behavioral responses to natural chemical stimuli by fish and crustaceans.

    Science.gov (United States)

    Derby, Charles D; Sorensen, Peter W

    2008-07-01

    This manuscript reviews the chemical ecology of two of the major aquatic animal models, fish and crustaceans, in the study of chemoreception. By necessity, it is restricted in scope, with most emphasis placed on teleost fish and decapod crustaceans. First, we describe the nature of the chemical world perceived by fish and crustaceans, giving examples of the abilities of these animals to analyze complex natural odors. Fish and crustaceans share the same environments and have evolved some similar chemosensory features: the ability to detect and discern mixtures of small metabolites in highly variable backgrounds and to use this information to identify food, mates, predators, and habitat. Next, we give examples of the molecular nature of some of these natural products, including a description of methodologies used to identify them. Both fish and crustaceans use their olfactory and gustatory systems to detect amino acids, amines, and nucleotides, among many other compounds, while fish olfactory systems also detect mixtures of sex steroids and prostaglandins with high specificity and sensitivity. Third, we discuss the importance of plasticity in chemical sensing by fish and crustaceans. Finally, we conclude with a description of how natural chemical stimuli are processed by chemosensory systems. In both fishes and crustaceans, the olfactory system is especially adept at mixture discrimination, while gustation is well suited to facilitate precise localization and ingestion of food. The behaviors of both fish and crustaceans can be defined by the chemical worlds in which they live and the abilities of their nervous systems to detect and identify specific features in their domains. An understanding of these worlds and the sensory systems that provide the animals with information about them provides insight into the chemical ecology of these species.

  12. Predicting the consequence of natural and chemical dispersion for oil slick size over time

    NARCIS (Netherlands)

    Marieke Zeinstra-Helfrich; Wierd Koops; Albertinka J. Murk

    2017-01-01

    In certain conditions, (part of) an oil spill can disappear from the water surface through a process called natural dispersion. One available oil spill response option is to enhance this process by addition of dispersants (chemical dispersion). An informed decision for such response requires insight

  13. Plant management in natural areas: balancing chemical, mechanical, and cultural control methods

    Science.gov (United States)

    Steven Manning; James. Miller

    2011-01-01

    After determining the best course of action for control of an invasive plant population, it is important to understand the variety of methods available to the integrated pest management professional. A variety of methods are now widely used in managing invasive plants in natural areas, including chemical, mechanical, and cultural control methods. Once the preferred...

  14. Water pollution by natural inorganic chemicals in the central part of ...

    African Journals Online (AJOL)

    The natural surface water and shallow groundwater quality in the Ethiopian Rift is influenced by excessive input of fluoride and some inorganic chemical constituents such as Li, Sr, Pb, Cu and Hg from the deep groundwater system. The surface water bodies are characterised by high fluoride, bicarbonate and chloride ...

  15. Using the Socioscientific Context of Climate Change to Teach Chemical Content and the Nature of Science

    Science.gov (United States)

    Flener-Lovitt, Charity

    2014-01-01

    A thematic course called "Climate Change: Chemistry and Controversy" was developed for upper-level non-STEM students. This course used the socioscientific context of climate change to teach chemical principles and the nature of science. Students used principles of agnotology (direct study of misinformation) to debunk climate change…

  16. Assessment of Application Technology of Natural User Interfaces in the Creation of a Virtual Chemical Laboratory

    Science.gov (United States)

    Jagodzinski, Piotr; Wolski, Robert

    2015-01-01

    Natural User Interfaces (NUI) are now widely used in electronic devices such as smartphones, tablets and gaming consoles. We have tried to apply this technology in the teaching of chemistry in middle school and high school. A virtual chemical laboratory was developed in which students can simulate the performance of laboratory activities similar…

  17. Expansion of chemical space for natural products by uncommon P450 reactions.

    Science.gov (United States)

    Zhang, Xingwang; Li, Shengying

    2017-08-30

    Covering: 2000 to 2017Cytochrome P450 enzymes (P450s) are the most versatile biocatalysts in nature. The catalytic competence of these extraordinary hemoproteins is broadly harnessed by numerous chemical defenders such as bacteria, fungi, and plants for the generation of diverse and complex natural products. Rather than the common tailoring reactions (e.g. hydroxylation and epoxidation) mediated by the majority of biosynthetic P450s, in this review, we will focus on the unusual P450 enzymes in relation to new chemistry, skeleton construction, and structure re-shaping via their own unique catalytic power or the intriguing protein-protein interactions between P450s and other proteins. These uncommon P450 reactions lead to a higher level of chemical space expansion for natural products, through which a broader spectrum of bioactivities can be gained by the host organisms.

  18. Marked influence of the nature of chemical bond on CP-violating signature in molecular ions $\\mathrm{HBr}^{+}$ and $\\mathrm{HI}^{+}$

    CERN Document Server

    Ravaine, B; Derevianko, A; Ravaine, Boris; Porsev, Sergey G.; Derevianko, Andrei

    2004-01-01

    Heavy polar molecules offer a great sensitivity to the electron Electric Dipole Moment(EDM). To guide emerging searches for EDMs with molecular ions, we estimate the EDM-induced energy corrections for hydrogen halide ions $\\mathrm{HBr}^{+}$ and $\\mathrm{HI}^{+}$ in their respective ground $X ^2\\Pi_{3/2}$ states. We find that the energy corrections due to EDM for the two ions differ by an unexpectedly large factor of fifteen. We demonstrate that a major part of this enhancement is due to a dissimilarity in the nature of the chemical bond for the two ions: the bond that is nearly of ionic character in $\\mathrm{HBr}^{+}$ exhibits predominantly covalent nature in $\\mathrm{HI}^{+}$. We conclude that because of this enhancement the HI$^+$ ion may be a potentially competitive candidate for the EDM search.

  19. Bioprospecting of Marine Invertebrates for New Natural Products — A Chemical and Zoogeographical Perspective

    Directory of Open Access Journals (Sweden)

    Ricardo Calado

    2012-08-01

    Full Text Available Bioprospecting for new marine natural products (NPs has increased significantly over the last decades, leading to an unprecedented discovery of new molecules. Marine invertebrates have been the most important source of these NPs, with researchers commonly targeting particular taxonomic groups, marine regions and/or molecules from specific chemical groups. The present review focuses on new NPs identified from marine invertebrates between 2000 and 2009, and performs a detailed analysis on: (1 the chemical groups of these NPs; (2 the association of particular chemical groups to specific marine invertebrate taxa; and (3 the yielding of molecules from the same chemical group from organisms occurring in a particular geographic region. Our survey revealed an increasing number of new terpenoids being discovered between 2000 and 2009, contrasting with the decreasing trend in the discovery of new alkaloids and aliphatic molecules. Overall, no particular association was identified between marine invertebrate taxa and chemical groups of new NPs. Nonetheless, it is worth noting that most NPs recorded from cnidarians and mollusks were terpenoids, while most NPs identified in echinoderms were aliphatic compounds or carbohydrates. The geographical trends observed in our study do not support the idea of particular chemical groups of new NPs being associated with marine invertebrates from any specific geographical region, as NPs from different chemical groups were commonly distributed worldwide.

  20. Bioprospecting of marine invertebrates for new natural products - a chemical and zoogeographical perspective.

    Science.gov (United States)

    Leal, Miguel Costa; Madeira, Carolina; Brandão, Cláudio Alexandre; Puga, João; Calado, Ricardo

    2012-08-16

    Bioprospecting for new marine natural products (NPs) has increased significantly over the last decades, leading to an unprecedented discovery of new molecules. Marine invertebrates have been the most important source of these NPs, with researchers commonly targeting particular taxonomic groups, marine regions and/or molecules from specific chemical groups. The present review focuses on new NPs identified from marine invertebrates between 2000 and 2009, and performs a detailed analysis on: (1) the chemical groups of these NPs; (2) the association of particular chemical groups to specific marine invertebrate taxa; and (3) the yielding of molecules from the same chemical group from organisms occurring in a particular geographic region. Our survey revealed an increasing number of new terpenoids being discovered between 2000 and 2009, contrasting with the decreasing trend in the discovery of new alkaloids and aliphatic molecules. Overall, no particular association was identified between marine invertebrate taxa and chemical groups of new NPs. Nonetheless, it is worth noting that most NPs recorded from cnidarians and mollusks were terpenoids, while most NPs identified in echinoderms were aliphatic compounds or carbohydrates. The geographical trends observed in our study do not support the idea of particular chemical groups of new NPs being associated with marine invertebrates from any specific geographical region, as NPs from different chemical groups were commonly distributed worldwide.

  1. Effects of Jigsaw Cooperative Learning and Animation Techniques on Students' Understanding of Chemical Bonding and Their Conceptions of the Particulate Nature of Matter

    Science.gov (United States)

    Karacop, Ataman; Doymus, Kemal

    2013-04-01

    The aim of this study was to determine the effect of jigsaw cooperative learning and computer animation techniques on academic achievements of first year university students attending classes in which the unit of chemical bonding is taught within the general chemistry course and these students' learning of the particulate nature of matter of this unit. The sample of this study consisted of 115 first-year science education students who attended the classes in which the unit of chemical bonding was taught in a university faculty of education during the 2009-2010 academic year. The data collection instruments used were the Test of Scientific Reasoning, the Purdue Spatial Visualization Test: Rotations, the Chemical Bonding Academic Achievement Test, and the Particulate Nature of Matter Test in Chemical Bonding (CbPNMT). The study was carried out in three different groups. One of the groups was randomly assigned to the jigsaw group, the second was assigned to the animation group (AG), and the third was assigned to the control group, in which the traditional teaching method was applied. The data obtained with the instruments were evaluated using descriptive statistics, one-way ANOVA, and MANCOVA. The results indicate that the teaching of chemical bonding via the animation and jigsaw techniques was more effective than the traditional teaching method in increasing academic achievement. In addition, according to findings from the CbPNMT, the students from the AG were more successful in terms of correct understanding of the particulate nature of matter.

  2. Processing and stabilization of Aloe Vera leaf gel by adding chemical and natural preservatives

    Directory of Open Access Journals (Sweden)

    N. Nazemi

    2017-11-01

    Full Text Available Background and objectives: Aloe vera has been used as a medicinal herb for thousands of years. Aloe vera leaves can be separated into latex and gel which have biological effects. Aloe gel is a potent source of polysaccharides. When the gel is exposed to air, it quickly decomposes and decays and loses most of its biological activity. There are various processing techniques for sterilizing and stabilizing the gel. The aim of this study was to improve stabilization of the gel by adding some chemical and natural preservatives. Methods: The gel was obtained from Aloe vera leaves and after some processing chemical and natural preservatives were added. Chemicals included citric acid, ascorbic acid, vitamin E and potassium sorbate while natural preservatives were two essential oils derived from Cinnamomum zeylanicum and Eugenia caryophyllata. All these operations were performed under sterile conditions and they were evaluated at different temperatures and times. Appearance and taste changes of gel were studied organoleptic. Microbiological tests and some physical assays such as pH, refractometry and viscosity properties as well as determination of total sugars were measured. NMR and FT-IR analyses were performed for determining the quality of samples. Results: After data analyzing, the results showed that the samples formulated with chemical additives together with essential oils were more suitable and stable compared to the control samples after 90 days and the effective ingredient acemannan, remained stable. Conclusion: The stable gel can be considered for therapeutic properties and be used for edible and medicinal purposes.

  3. Angle-Resolved HAXPES Investigation on the Chemical Origin of Adhesion between Natural Rubber and Brass.

    Science.gov (United States)

    Ozawa, Kenichi; Kakubo, Takashi; Amino, Naoya; Mase, Kazuhiko; Ikenaga, Eiji; Nakamura, Tetsuya

    2017-09-26

    Bulk sensitivity of hard X-ray photoelectron spectroscopy (HAXPES) makes this technique suitable for chemical state analysis of bulk and deeply buried interfaces of solid materials. HAXPES is employed in the present study to examine the chemical state of adhesive interfaces between natural rubber and copper-zinc alloy, i.e., brass, while maintaining the adhesion structure in order to understand the chemical mechanism of rubber-to-brass adhesion. Angle-resolved measurements allow to distinguish between chemical species in rubber and those at the adhesive interface. We specially focus on sulfur-containing species because metal sulfides at the interface have been suggested to be crucial for adhesion. Line-shape analysis of S 1s spectra reveals that the interface that exhibits a strong adhesive property is mainly composed of copper sulfides with a predominant amount of CuS. This type of the interfacial chemical state is obtained when a rubber-bonded brass sample is subjected to vulcanization at 170 °C for 10 min. However, prolonged vulcanization leads to a partial dissolution of CuS as well as accumulation of Zn species in the form of ZnO/Zn(OH)2 and ZnS, and as a result, adhesion strength is lowered. The present study paves the way for accurate and detailed discussion on the chemical state of deeply buried interfaces through bulk sensitive in-situ measurements.

  4. Natural products as biofuels and bio-based chemicals: fatty acids and isoprenoids.

    Science.gov (United States)

    Beller, Harry R; Lee, Taek Soon; Katz, Leonard

    2015-09-23

    Although natural products are best known for their use in medicine and agriculture, a number of fatty acid-derived and isoprenoid natural products are being developed for use as renewable biofuels and bio-based chemicals. This review summarizes recent work on fatty acid-derived compounds (fatty acid alkyl esters, fatty alcohols, medium- and short-chain methyl ketones, alkanes, α-olefins, and long-chain internal alkenes) and isoprenoids, including hemiterpenes (e.g., isoprene and isopentanol), monoterpenes (e.g., limonene), and sesquiterpenes (e.g., farnesene and bisabolene).

  5. Integrating artificial with natural cells to translate chemical messages that direct E. coli behaviour

    Science.gov (United States)

    Lentini, Roberta; Santero, Silvia Perez; Chizzolini, Fabio; Cecchi, Dario; Fontana, Jason; Marchioretto, Marta; Del Bianco, Cristina; Terrell, Jessica L.; Spencer, Amy C.; Martini, Laura; Forlin, Michele; Assfalg, Michael; Serra, Mauro Dalla; Bentley, William E.; Mansy, Sheref S.

    2014-01-01

    Previous efforts to control cellular behaviour have largely relied upon various forms of genetic engineering. Once the genetic content of a living cell is modified, the behaviour of that cell typically changes as well. However, other methods of cellular control are possible. All cells sense and respond to their environment. Therefore, artificial, non-living cellular mimics could be engineered to activate or repress already existing natural sensory pathways of living cells through chemical communication. Here we describe the construction of such a system. The artificial cells expand the senses of Escherichia coli by translating a chemical message that E. coli cannot sense on its own to a molecule that activates a natural cellular response. This methodology could open new opportunities in engineering cellular behaviour without exploiting genetically modified organisms. PMID:24874202

  6. Integrating artificial with natural cells to translate chemical messages that direct E. coli behaviour.

    Science.gov (United States)

    Lentini, Roberta; Santero, Silvia Perez; Chizzolini, Fabio; Cecchi, Dario; Fontana, Jason; Marchioretto, Marta; Del Bianco, Cristina; Terrell, Jessica L; Spencer, Amy C; Martini, Laura; Forlin, Michele; Assfalg, Michael; Dalla Serra, Mauro; Bentley, William E; Mansy, Sheref S

    2014-05-30

    Previous efforts to control cellular behaviour have largely relied upon various forms of genetic engineering. Once the genetic content of a living cell is modified, the behaviour of that cell typically changes as well. However, other methods of cellular control are possible. All cells sense and respond to their environment. Therefore, artificial, non-living cellular mimics could be engineered to activate or repress already existing natural sensory pathways of living cells through chemical communication. Here we describe the construction of such a system. The artificial cells expand the senses of Escherichia coli by translating a chemical message that E. coli cannot sense on its own to a molecule that activates a natural cellular response. This methodology could open new opportunities in engineering cellular behaviour without exploiting genetically modified organisms.

  7. Degradation of non-vulcanized natural rubber - renewable resource for fine chemicals used in polymer synthesis

    Directory of Open Access Journals (Sweden)

    Alexander Fainleib

    2013-01-01

    Full Text Available In the current scenario, there is growing interest in the products of degradation of rubber (natural and synthetic for specific applications in different industry sectors, whose benefits in replacing conventionally used products are mainly related to sustainability. Since the degradation products of rubber can be used in different areas, several research groups may have the interest aroused by these products, but are not familiar with the aspects related to the chemical behavior of rubber. This review aims to bring together the key information in the published literature on the degradation of natural rubber, emphasizing metatheses reactions, oxidative damage and splitting of the double bond, in order to serve as a reference source for researchers from different fields interested in obtaining such kind of products. The structures and properties as well as additional chemical transformations resulting in oligomers of isoprene, functionalised oligomers and polymers based on both are also described.

  8. Grasping the nature of the cell interior: from Physiological Chemistry to Chemical Biology.

    Science.gov (United States)

    Kyne, Ciara; Crowley, Peter B

    2016-08-01

    Current models of the cell interior emphasise its crowded, chemically complex and dynamically organised structure. Although the chemical composition of cells is known, the cooperative intermolecular interactions that govern cell ultrastructure are poorly understood. A major goal of biochemistry is to capture these myriad interactions in vivo. We consider the landmark discoveries that have shaped this objective, starting from the vitalist framework established by early natural philosophers. Through this historical revisionism, we extract important lessons for the bioinspired chemists of today. Scientific specialisation tends to insulate seminal ideas and hamper the unification of paradigms across biology. Therefore, we call for interdisciplinary collaboration in grappling with the complex cell interior. Recent successes in integrative structural biology and chemical biology demonstrate the power of hybrid approaches. The future roles of the (bio)chemist and model systems are also discussed as starting points for in vivo explorations. © 2016 Federation of European Biochemical Societies.

  9. Phase I Focused Corrective Measures Study/Feasibility Study for the L-Area Oil and Chemical Basin (904-83G)

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, E. [Westinghouse Savannah River Company, AIKEN, SC (United States)

    1997-02-01

    This report presents the completed Resource Conservation and Recovery Act (RCRA) Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Focused Corrective Measures Study/Feasibility Study (CMS/FS) for the L-Area Oil and Chemical Basin (LAOCB)/L-Area Acid Caustic Basin (9LAACB) Solid Waste Management Unit/Operable Unit (SWMU/OU) at the Savannah River Site (SRS).

  10. Chemical Promotion of Endogenous Amounts of ABA in Arabidopsis thaliana by a Natural Product, Theobroxide.

    Science.gov (United States)

    Yamashita, Yudai; Ota, Maremichi; Inoue, Yutaka; Hasebe, Youko; Okamoto, Masanori; Inukai, Tsuyoshi; Masuta, Chikra; Sakihama, Yasuko; Hashidoko, Yasuyuki; Kojima, Mikiko; Sakakibara, Hitoshi; Inage, Yasuyuki; Takahashi, Kosaku; Yoshihara, Teruhiko; Matsuura, Hideyuki

    2016-05-01

    Plant hormones are a group of structurally diverse small compounds that orchestrate the cellular processes governing proper plant growth and environmental adaptation. To understand the details of hormonal activity, we must study not only their inherent activities but also the cross-talk among plant hormones. In addition to their use in agriculture, plant chemical activators, such as probenazole and uniconazole, have made great contributions to understand hormonal cross-talk. However, the use of plant chemical activators is limited due to the lack of activators for certain hormones. For example, to the best of our knowledge, there are only a few chemical activators previously known to stimulate the accumulation of ABA in plants, such as absinazoles and proanthocyanidins. In many cases, antagonistic effects have been examined in experiments using exogenously applied ABA, although these studies did not account for biologically relevant concentrations. In this report, it was found that a natural product, theobroxide, had potential as a plant chemical activator for stimulating the accumulation of ABA. Using theobroxide, the antagonistic effect of ABA against GAs was proved without exogenously applying ABA or using mutant plants. Our results suggest that ABA levels could be chemically controlled to elicit ABA-dependent biological phenomena. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  11. Treatment of Actual Chemical Wastewater by a Heterogeneous Fenton Process Using Natural Pyrite.

    Science.gov (United States)

    Sun, Liang; Li, Yan; Li, Aimin

    2015-10-28

    Wastewater from chemical plants has remarkable antibiotic effects on the microorganisms in traditional biological treatment processes. An enhanced Fenton system catalyzed by natural pyrite was developed to degrade this kind of wastewater. Approximately 30% chemical oxygen demand (COD) was removed within 120 min when 50 mmol/L H₂O₂ and 10 g/L natural pyrite were used at initial pH from 1.8 to 7. A BOD₅/COD enhancement efficiency of 210% and an acute biotoxicity removal efficiency of 84% were achieved. The COD removal efficiency was less sensitive to initial pH than was the classic Fenton process. Excessive amounts of pyrite and H₂O₂ did not negatively affect the pyrite Fenton system. The amount of aniline generated indicated that nitrobenzene reduction by pyrite was promoted using a low initial concentration of H₂O₂ (reduction by natural pyrite of organic molecules containing an electron-withdrawing group to electron-donating group. Thus, the Fenton-like process catalyzed by pyrite can remediate wastewater containing organic pollutants under mild reaction conditions and provide an alternative environmentally friendly method by which to reuse natural pyrite.

  12. Treatment of Actual Chemical Wastewater by a Heterogeneous Fenton Process Using Natural Pyrite

    Directory of Open Access Journals (Sweden)

    Liang Sun

    2015-10-01

    Full Text Available Wastewater from chemical plants has remarkable antibiotic effects on the microorganisms in traditional biological treatment processes. An enhanced Fenton system catalyzed by natural pyrite was developed to degrade this kind of wastewater. Approximately 30% chemical oxygen demand (COD was removed within 120 min when 50 mmol/L H2O2 and 10 g/L natural pyrite were used at initial pH from 1.8 to 7. A BOD5/COD enhancement efficiency of 210% and an acute biotoxicity removal efficiency of 84% were achieved. The COD removal efficiency was less sensitive to initial pH than was the classic Fenton process. Excessive amounts of pyrite and H2O2 did not negatively affect the pyrite Fenton system. The amount of aniline generated indicated that nitrobenzene reduction by pyrite was promoted using a low initial concentration of H2O2 (<5 mmol/L. Fluorescence excitation emission matrix analyses illustrated that H2O2 facilitated the reduction by natural pyrite of organic molecules containing an electron-withdrawing group to electron-donating group. Thus, the Fenton-like process catalyzed by pyrite can remediate wastewater containing organic pollutants under mild reaction conditions and provide an alternative environmentally friendly method by which to reuse natural pyrite.

  13. Linear analysis of carbon-13 chemical shift differences and its application to the detection and correction of errors in referencing and spin system identifications.

    Science.gov (United States)

    Wang, Liya; Eghbalnia, Hamid R; Bahrami, Arash; Markley, John L

    2005-05-01

    Statistical analysis reveals that the set of differences between the secondary shifts of the alpha- and beta-carbons for residues i of a protein (Deltadelta13C(alpha)i - Deltadelta13C(beta)i) provides the means to detect and correct referencing errors for 1H and 13C nuclei within a given dataset. In a correctly referenced protein dataset, linear regression plots of Deltadelta13C(alpha)i, Deltadelta13C(beta)i, or Deltadelta1H(alpha)i vs. (Deltadelta13C(alpha)i - Deltadelta13C(beta)i) pass through the origin from two directions, the helix-to-coil and strand-to-coil directions. Thus, linear analysis of chemical shifts (LACS) can be used to detect referencing errors and to recalibrate the 1H and 13C chemical shift scales if needed. The analysis requires only that the signals be identified with distinct residue types (intra-residue spin systems). LACS allows errors in calibration to be detected and corrected in advance of sequence-specific assignments and secondary structure determinations. Signals that do not fit the linear model (outliers) deserve scrutiny since they could represent errors in identifying signals with a particular residue, or interesting features such as a cis-peptide bond. LACS provides the basis for the automated detection of such features and for testing reassignment hypotheses. Early detection and correction of errors in referencing and spin system identifications can improve the speed and accuracy of chemical shift assignments and secondary structure determinations. We have used LACS to create a database of offset-corrected chemical shifts corresponding to nearly 1800 BMRB entries: 300 with and 1500 without corresponding three-dimensional (3D) structures. This database can serve as a resource for future analysis of the effects of amino acid sequence and protein secondary and tertiary structure on NMR chemical shifts.

  14. Charting, navigating, and populating natural product chemical space for drug discovery.

    Science.gov (United States)

    Lachance, Hugo; Wetzel, Stefan; Kumar, Kamal; Waldmann, Herbert

    2012-07-12

    Natural products are a heterogeneous group of compounds with diverse, yet particular molecular properties compared to synthetic compounds and drugs. All relevant analyses show that natural products indeed occupy parts of chemical space not explored by available screening collections while at the same time largely adhering to the rule-of-five. This renders them a valuable, unique, and necessary component of screening libraries used in drug discovery. With ChemGPS-NP on the Web and Scaffold Hunter two tools are available to the scientific community to guide exploration of biologically relevant NP chemical space in a focused and targeted fashion with a view to guide novel synthesis approaches. Several of the examples given illustrate the possibility of bridging the gap between computational methods and compound library synthesis and the possibility of integrating cheminformatics and chemical space analyses with synthetic chemistry and biochemistry to successfully explore chemical space for the identification of novel small molecule modulators of protein function.The examples also illustrate the synergistic potential of the chemical space concept and modern chemical synthesis for biomedical research and drug discovery. Chemical space analysis can map under explored biologically relevant parts of chemical space and identify the structure types occupying these parts. Modern synthetic methodology can then be applied to efficiently fill this “virtual space” with real compounds.From a cheminformatics perspective, there is a clear demand for open-source and easy to use tools that can be readily applied by educated nonspecialist chemists and biologists in their daily research. This will include further development of Scaffold Hunter, ChemGPS-NP, and related approaches on the Web. Such a “cheminformatics toolbox” would enable chemists and biologists to mine their own data in an intuitive and highly interactive process and without the need for specialized computer

  15. Effect of oxygen ion irradiation on dielectric, structural, chemical and thermoluminescence properties of natural muscovite mica.

    Science.gov (United States)

    Kaur, Sukhnandan; Singh, Surinder; Singh, Lakhwant

    2017-03-01

    Thin cleaved samples (~18µm) of natural muscovite mica were irradiated with 80MeV oxygen ion beam at fluence ranging from 1×1012 to 5×1013ion/cm2. The alterations in dielectric, structural, chemical and thermoluminescence properties of irradiated as well as pristine samples have been investigated. Dielectric constant decreases while other dielectric parameters such as dielectric loss, tanδ, ac conductivity, real and imaginary parts of electric modulus increase with increase of ion fluence. Williamson Hall investigation has been utilized to ascertain crystallite size and micro strain of pristine and irradiated samples. The XRD analysis revealed a significant increase in micro strain and dislocation density with an increase of ion fluence. The variations in dielectric properties upon irradiation are collaborated with structural modifications in the muscovite. No appreciable changes in characteristic bands (FTIR) have been observed after irradiation, indicating that natural muscovite mica is chemically stable. Natural muscovite mica has eminent applications in heavy ions dosimetry due to observation of well defined single peak at 303°C with activation energy of 1.24eV in TL spectrum. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Non-Natural Sugar Analogues: Chemical Probes for Metabolic Oligosaccharide Engineering

    Science.gov (United States)

    Aich, Udayanath; Yarema, Kevin J.

    Metabolic oligosaccharide engineering (MOE) is a rapidly growing technology emerging from the field of chemical biology that allows novel chemical functionalities to be biosynthetically installed into the carbohydrates of living cells and animals. Since pioneering efforts to modulate sialic acid display through the use of non-natural N-acetyl-D-mannosamine (ManNAc) analogues were reported 15 years ago, monosaccharide probes have been developed to manipulate N-acetyl-D-galactosamine (GalNAc), N-acetyl-D-glucosamine (GlcNAc), and fucose-containing glycans. The 'first generation' of analogues, comprised of a series of ManNAc derivatives with elongated N-acyl chains, demonstrated pathway permissivity and the ability of this methodology to impinge on biological processes ranging from pathogen binding to gene expression and cell adhesion. Later analogues have incorporated chemical function groups including ketones, azides, thiols, and alkyne not normally found in carbohydrates. These groups serve as 'tags' for the subsequent use of chemoselective ligation reactions to further elaborate the chemical properties of the cell surface and thereby greatly expand the potential of MOE technology to offer control over biological processes.

  17. Experimental Observation of the Nature of Weak Chemical Bonds in Labile Compounds.

    Science.gov (United States)

    Hashizume, Daisuke

    2017-07-01

    Accurate single-crystal X-ray diffraction data afford a total electron density distribution for crystalline materials by employing an aspherical atomic model with comparable accuracy to that of theoretical calculations. Chemical bonds and intermolecular interactions in the crystalline state are characterized based on the electron density distribution of valence electrons, as well as structural parameters. Herein, the bonding nature of weak chemical bonds in labile compounds, such as hypervalent bonds and delocalized π-bonds, is explored on the basis of electronic structures derived from experimental electron density distribution analyses. In addition, the visualization of a radicalic orbital distribution on an sp 2 -hydridized carbon atom is demonstrated. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Novel, cyclic heat dissipation method for the correction of natural temperature gradients in sap flow measurements. Part 2. Laboratory validation.

    Science.gov (United States)

    Reyes-Acosta, J Leonardo; Vandegehuchte, Maurits W; Steppe, Kathy; Lubczynski, Maciek W

    2012-07-01

    Sap flow measurements conducted with thermal dissipation probes (TDPs) are vulnerable to natural temperature gradient (NTG) bias. Few studies, however, attempted to explain the dynamics underlying the NTG formation and its influence on the sensors' signal. This study focused on understanding how the TDP signals are affected by negative and positive temperature influences from NTG and tested the novel cyclic heat dissipation (CHD) method to filter out the NTG bias. A series of three experiments were performed in which gravity-driven water flow was enforced on freshly cut stem segments of Fagus sylvatica L., while an artificial temperature gradient (ATG) was induced. The first experiment sought to confirm the incidence of the ATG on sensors. The second experiment established the mis-estimations caused by the biasing effect of the ATG on standard TDP measurements. The third experiment tested the accuracy of the CHD method to account for the ATG biasing effect, as compared with other cyclic correction methods. During experiments, sap flow measured by TDP was assessed against gravimetric measurements. The results show that negative and positive ATGs were comparable in pattern but substantially larger than field NTGs. Second, the ATG bias caused an overestimation of the standard TDP sap flux density of ∼17 cm(3) cm(-2) h(-1) by 76%, and the sap flux density of ∼2 cm(3) cm(-2) h(-1) by over 800%. Finally, the proposed CHD method successfully reduced the max. ATG bias to 25% at ∼11 cm(3) cm(-2) h(-1) and to 40% at ∼1 cm(3) cm(-2) h(-1). We concluded that: (i) the TDP method is susceptible to NTG especially at low flows; (ii) the CHD method successfully corrected the TDP signal and resulted in generally more accurate sap flux density estimates (mean absolute percentage error ranging between 11 and 21%) than standard constant power TDP method and other cyclic power methods; and (iii) the ATG enforcing system is a suitable way of re-creating NTG for future tests.

  19. Electronic structure and chemical bond nature in Cs2NpO2Cl4

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2017-01-01

    Full Text Available On the basis of the X-ray photoelectron spectroscopy data and results of theoretical calculations for the NpO2Cl4 (D4h cluster, the electronic structure and the chemical bond nature in , was done in the binding Cs2NpO2Cl4 single crystal, containing the neptunyl group NpO2 energy range of 0 eV to ~35 eV. The filled Np 5f electronic states were established to form in the valence band of Cs2NpO2Cl4. This was attributed to the direct participation of the Np 5f electrons in the chemical bonding. The Np 6p electrons were shown to participate in formation of both the inner valence band (~15 eV-~35 eV and the outer valence band (0 eV-~15 eV. The filled Np 6p and the O 2s, Cl 3s electronic shells were found to make the largest contribution to the formation of the inner valence molecular orbitals. The molecular orbitals composition and the sequence order in the binding energy range 0 eV-~35 eV in Cs2NpO2Cl4, were established. For the first time the quantitative scheme of molecular orbitals for the NpO2Cl4 cluster in the binding energy range 0 eV-~35 eV, was built. This scheme reflects neptunium close environment in the studied compound and is fundamental for both understanding the chemical bond nature in Cs2NpO2Cl4 and the interpretation of other X-ray spectra of Cs2NpO2Cl4. The contributions to the chemical binding for the NpO2Cl4 cluster were evaluated to be: the outer valence molecular orbitals contribution - 73 %, and the inner valence molecular orbitals contribution - 27 %.

  20. Linear analysis of carbon-13 chemical shift differences and its application to the detection and correction of errors in referencing and spin system identifications

    Energy Technology Data Exchange (ETDEWEB)

    Wang Liya; Eghbalnia, Hamid R., E-mail: eghbalni@nmrfam.wisc.edu; Bahrami, Arash; Markley, John L. [Biochemistry Department, National Magnetic Resonance Facility at Madison (United States)

    2005-05-15

    Statistical analysis reveals that the set of differences between the secondary shifts of the {alpha}- and {beta}-carbons for residues i of a protein ({delta}{delta}{sup 13}C{sup {alpha}}{sub i}- {delta}{delta}{sup 13}C{sup {beta}}{sub i}) provides the means to detect and correct referencing errors for {sup 1}H and {sup 13}C nuclei within a given dataset. Linear analysis of chemical shifts (LACS) can be used to detect referencing errors and to recalibrate the {sup 1}H and {sup 13}C chemical shift scales if needed. The analysis requires only that the signals be identified with distinct residue types (intra-residue spin systems). LACS allows errors in calibration to be detected and corrected in advance of sequence-specific assignments and secondary structure determinations. Signals that do not fit the linear model (outliers) deserve scrutiny since they could represent errors in identifying signals with a particular residue, or interesting features such as a cis-peptide bond. LACS provides the basis for the automated detection of such features and for testing reassignment hypotheses. Early detection and correction of errors in referencing and spin system identifications can improve the speed and accuracy of chemical shift assignments and secondary structure determinations. We have used LACS to create a database of offset-corrected chemical shifts corresponding to nearly 1800 BMRB entries: 300 with and 1500 without corresponding three-dimensional (3D) structures. This database can serve as a resource for future analysis of the effects of amino acid sequence and protein secondary and tertiary structure on NMR chemical shifts.

  1. Differences in erect sitting and natural sitting spinal alignment-insights into a new paradigm and implications in deformity correction.

    Science.gov (United States)

    Hey, Hwee Weng Dennis; Wong, Chengyuan Gordon; Lau, Eugene Tze-Chun; Tan, Kimberly-Anne; Lau, Leok-Lim; Liu, Ka-Po Gabriel; Wong, Hee-Kit

    2017-02-01

    Sitting spinal alignment is increasingly recognized as a factor influencing strategy for deformity correction. Considering that most individuals sit for longer hours in a "slumped" rather than in an erect posture, greater understanding of the natural sitting posture is warranted. This study aimed to investigate the differences in sagittal spinal alignment between two common sitting postures: a natural, patient-preferred posture; and an erect, investigator-controlled posture that is commonly used in alignment studies. This is a randomized, prospective study of 28 young, healthy patients seen in a tertiary hospital over a 6-month period. Twenty-eight patients (24 men, 4 women), with a mean age of 24 years (range 19-38), were recruited for this study. All patients with first episode of lower back pain of less than 3 months' duration were included. The exclusion criteria consisted of previous spinal surgery, radicular symptoms, red flag symptoms, previous spinal trauma, obvious spinal deformity on forward bending test, significant personal or family history of malignancy, and current pregnancy. Radiographic measurements included sagittal vertical axis (SVA), lumbar lordosis (LL), thoracolumbar angle (TL), thoracic kyphosis (TK), and cervical lordosis (CL). Standard spinopelvic parameters (pelvic incidence, pelvic tilt [PT], and sacral slope) and sagittal apex and end vertebrae were also measured. Basic patient demographics (age, gender, ethnicity) were recorded. Lateral sitting whole spine radiographs were obtained using a slot scanner in the imposed erect and the natural sitting posture. Statistical analyses of the radiographical parameters were performed comparing the two sitting postures using chi-squared tests for categorical variables and paired t tests for continuous variables. There was forward SVA shift between the two sitting postures by a mean of 2.9 cm (p<.001). There was a significant increase in CL by a mean of 11.62° (p<.001), and TL kyphosis by a mean

  2. Kinetics of Natural Attenuation: Review of the Critical Chemical Conditions and Measurements at Bore Scale

    Directory of Open Access Journals (Sweden)

    O. Atteia

    2002-01-01

    Full Text Available This paper describes the chemical conditions that should favour the biodegradation of organic pollutants. Thermodynamic considerations help to define the reaction that can occur under defined chemical conditions. The BTEX (benzene, toluene, ethylbenzene, and xylene degradation is focused on benzene, as it is the most toxic oil component and also because it has the slowest degradation rate under most field conditions. Several studies on benzene degradation allow the understanding of the basic degradation mechanisms and their importance in field conditions. The use of models is needed to interpret field data when transport, retardation, and degradation occur. A detailed comparison of two existing models shows that the limits imposed by oxygen transport must be simulated precisely to reach correct plumes shapes and dimensions, and that first-order kinetic approaches may be misleading. This analysis led us to develop a technique to measure directly biodegradation in the field. The technique to recirculate water at the borehole scale and the CO2 analysis are depicted. First results of biodegradation show that this technique is able to easily detect the degradation of 1 mg/l of hydrocarbons and that, in oxic media, a fast degradation rate of mixed fuel is observed.

  3. Natural Chemical Composition of Commercial Fish Species: Characterisation of Pangasius, Wild and Farmed Turbot and Barramundi

    Directory of Open Access Journals (Sweden)

    Monika Manthey-Karl

    2016-08-01

    Full Text Available To comply with the relevant legal requirements and correct labelling, it is necessary for business operators and inspection authorities to know the natural characteristics of the raw material. This study gives a comprehensive overview of muscle flesh composition of farmed and wild Atlantic turbot (Scophthalmus maximus and barramundi (Lates calcarifer and of farmed pangasius (Pangasianodon hypophthalmus. The proximate composition, di- and triphosphates and citric acid values are presented in order to evaluate possible indicators for a hidden treatment during processing to fillets. All moisture contents were ≤80%. Even for pangasius, protein values for deep skinned fillets of ≥18% were determined. Only small quantities of naturally occurring citric acid (up to 0.03 g·kg−1 were detectable. The lipid content was the most varying main component within the different species, ranging between 1.2% to 2.0% and 0.3% to 3.0% for farmed turbot and barramundi, respectively. Pangasius flesh had a mean lipid content of 7.8%. Trimming and separation of the red layer reduced the lipid content of the commercially sold white-flesh fillets to 2.7% to 3.5%. Fatty acids profiles, free amino acids, and minerals were analysed to show the nutritional quality of the aquaculture fish species and compared to wild turbot and barramundi. Despite some natural variation, these components can be considered as comparable.

  4. Natural Chemical Composition of Commercial Fish Species: Characterisation of Pangasius, Wild and Farmed Turbot and Barramundi

    Science.gov (United States)

    Manthey-Karl, Monika; Lehmann, Ines; Ostermeyer, Ute; Schröder, Ute

    2016-01-01

    To comply with the relevant legal requirements and correct labelling, it is necessary for business operators and inspection authorities to know the natural characteristics of the raw material. This study gives a comprehensive overview of muscle flesh composition of farmed and wild Atlantic turbot (Scophthalmus maximus) and barramundi (Lates calcarifer) and of farmed pangasius (Pangasianodon hypophthalmus). The proximate composition, di- and triphosphates and citric acid values are presented in order to evaluate possible indicators for a hidden treatment during processing to fillets. All moisture contents were ≤80%. Even for pangasius, protein values for deep skinned fillets of ≥18% were determined. Only small quantities of naturally occurring citric acid (up to 0.03 g·kg−1) were detectable. The lipid content was the most varying main component within the different species, ranging between 1.2% to 2.0% and 0.3% to 3.0% for farmed turbot and barramundi, respectively. Pangasius flesh had a mean lipid content of 7.8%. Trimming and separation of the red layer reduced the lipid content of the commercially sold white-flesh fillets to 2.7% to 3.5%. Fatty acids profiles, free amino acids, and minerals were analysed to show the nutritional quality of the aquaculture fish species and compared to wild turbot and barramundi. Despite some natural variation, these components can be considered as comparable. PMID:28231154

  5. Characterization of performance reference compound kinetics and analyte sampling rate corrections under three flow regimes using nylon organic chemical integrative samplers.

    Science.gov (United States)

    Morrison, Shane A; Belden, Jason B

    2016-09-30

    Performance reference compounds (PRCs) can be spiked into passive samplers prior to deployment. If the dissipation kinetics of PRCs from the sampler corresponds to analyte accumulation kinetics, then PRCs can be used to estimate in-situ sampling rates, which may vary depending on environmental conditions. Under controlled laboratory conditions, the effectiveness of PRC corrections on prediction accuracy of water concentrations were evaluated using nylon organic chemical integrative samplers (NOCIS). Results from PRC calibrations suggest that PRC elimination occurs faster under higher flow conditions; however, minimal differences were observed for PRC elimination between fast flow (9.3cm/s) and slow flow (5.0cm/s) conditions. Moreover, minimal differences were observed for PRC elimination from Dowex Optipore L-493; therefore, PRC corrections did not improve results for NOCIS configurations containing Dowex Optipore L-493. Regardless, results suggest that PRC corrections were beneficial for NOCIS configurations containing Oasis HLB; however, due to differences in flow dependencies of analyte sampling rates and PRC elimination rates across the investigated flow regimes, the use of multiple PRC corrections was necessary. As such, a "Best-Fit PRC" approach was utilized for Oasis HLB corrections using caffeine-(13)C3, DIA-d5, or no correction based on the relative flow dependencies of analytes and these PRCs. Although PRC corrections reduced the variability when in-situ conditions differed from laboratory calibrations (e.g. static versus moderate flow), applying PRC corrections under similar flow conditions increases variability in estimated values. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Chemical analyses of wasp-associated streptomyces bacteria reveal a prolific potential for natural products discovery.

    Directory of Open Access Journals (Sweden)

    Michael Poulsen

    2011-02-01

    Full Text Available Identifying new sources for small molecule discovery is necessary to help mitigate the continuous emergence of antibiotic-resistance in pathogenic microbes. Recent studies indicate that one potentially rich source of novel natural products is Actinobacterial symbionts associated with social and solitary Hymenoptera. Here we test this possibility by examining two species of solitary mud dauber wasps, Sceliphron caementarium and Chalybion californicum. We performed enrichment isolations from 33 wasps and obtained more than 200 isolates of Streptomyces Actinobacteria. Chemical analyses of 15 of these isolates identified 11 distinct and structurally diverse secondary metabolites, including a novel polyunsaturated and polyoxygenated macrocyclic lactam, which we name sceliphrolactam. By pairing the 15 Streptomyces strains against a collection of fungi and bacteria, we document their antifungal and antibacterial activity. The prevalence and anti-microbial properties of Actinobacteria associated with these two solitary wasp species suggest the potential role of these Streptomyces as antibiotic-producing symbionts, potentially helping defend their wasp hosts from pathogenic microbes. Finding phylogenetically diverse and chemically prolific Actinobacteria from solitary wasps suggests that insect-associated Actinobacteria can provide a valuable source of novel natural products of pharmaceutical interest.

  7. Chemical Treatment of Waste Abaca for Natural Fiber-Reinforced Geopolymer Composite

    Science.gov (United States)

    Malenab, Roy Alvin J.; Ngo, Janne Pauline S.; Promentilla, Michael Angelo B.

    2017-01-01

    The use of natural fibers in reinforced composites to produce eco-friendly materials is gaining more attention due to their attractive features such as low cost, low density and good mechanical properties, among others. This work thus investigates the potential of waste abaca (Manila hemp) fiber as reinforcing agent in an inorganic aluminosilicate material known as geopolymer. In this study, the waste fibers were subjected to different chemical treatments to modify the surface characteristics and to improve the adhesion with the fly ash-based geopolymer matrix. Definitive screening design of experiment was used to investigate the effect of successive chemical treatment of the fiber on its tensile strength considering the following factors: (1) NaOH pretreatment; (2) soaking time in aluminum salt solution; and (3) final pH of the slurry. The results show that the abaca fiber without alkali pretreatment, soaked for 12 h in Al2(SO4)3 solution and adjusted to pH 6 exhibited the highest tensile strength among the treated fibers. Test results confirmed that the chemical treatment removes the lignin, pectin and hemicellulose, as well as makes the surface rougher with the deposition of aluminum compounds. This improves the interfacial bonding between geopolymer matrix and the abaca fiber, while the geopolymer protects the treated fiber from thermal degradation. PMID:28772936

  8. Chemical Treatment of Waste Abaca for Natural Fiber-Reinforced Geopolymer Composite.

    Science.gov (United States)

    Malenab, Roy Alvin J; Ngo, Janne Pauline S; Promentilla, Michael Angelo B

    2017-05-25

    The use of natural fibers in reinforced composites to produce eco-friendly materials is gaining more attention due to their attractive features such as low cost, low density and good mechanical properties, among others. This work thus investigates the potential of waste abaca (Manila hemp) fiber as reinforcing agent in an inorganic aluminosilicate material known as geopolymer. In this study, the waste fibers were subjected to different chemical treatments to modify the surface characteristics and to improve the adhesion with the fly ash-based geopolymer matrix. Definitive screening design of experiment was used to investigate the effect of successive chemical treatment of the fiber on its tensile strength considering the following factors: (1) NaOH pretreatment; (2) soaking time in aluminum salt solution; and (3) final pH of the slurry. The results show that the abaca fiber without alkali pretreatment, soaked for 12 h in Al₂(SO₄)₃ solution and adjusted to pH 6 exhibited the highest tensile strength among the treated fibers. Test results confirmed that the chemical treatment removes the lignin, pectin and hemicellulose, as well as makes the surface rougher with the deposition of aluminum compounds. This improves the interfacial bonding between geopolymer matrix and the abaca fiber, while the geopolymer protects the treated fiber from thermal degradation.

  9. Chemical Treatment of Waste Abaca for Natural Fiber-Reinforced Geopolymer Composite

    Directory of Open Access Journals (Sweden)

    Roy Alvin J. Malenab

    2017-05-01

    Full Text Available The use of natural fibers in reinforced composites to produce eco-friendly materials is gaining more attention due to their attractive features such as low cost, low density and good mechanical properties, among others. This work thus investigates the potential of waste abaca (Manila hemp fiber as reinforcing agent in an inorganic aluminosilicate material known as geopolymer. In this study, the waste fibers were subjected to different chemical treatments to modify the surface characteristics and to improve the adhesion with the fly ash-based geopolymer matrix. Definitive screening design of experiment was used to investigate the effect of successive chemical treatment of the fiber on its tensile strength considering the following factors: (1 NaOH pretreatment; (2 soaking time in aluminum salt solution; and (3 final pH of the slurry. The results show that the abaca fiber without alkali pretreatment, soaked for 12 h in Al2(SO43 solution and adjusted to pH 6 exhibited the highest tensile strength among the treated fibers. Test results confirmed that the chemical treatment removes the lignin, pectin and hemicellulose, as well as makes the surface rougher with the deposition of aluminum compounds. This improves the interfacial bonding between geopolymer matrix and the abaca fiber, while the geopolymer protects the treated fiber from thermal degradation.

  10. Chemical communication between synthetic and natural cells: a possible experimental design.

    Directory of Open Access Journals (Sweden)

    Livia Leoni

    2013-09-01

    Full Text Available The bottom-up construction of synthetic cells is one of the most intriguing and interesting research arenas in synthetic biology. Synthetic cells are built by encapsulating biomolecules inside lipid vesicles (liposomes, allowing the synthesis of one or more functional proteins. Thanks to the in situ synthesized proteins, synthetic cells become able to perform several biomolecular functions, which can be exploited for a large variety of applications. This paves the way to several advanced uses of synthetic cells in basic science and biotechnology, thanks to their versatility, modularity, biocompatibility, and programmability. In the previous WIVACE (2012 we presented the state-of-the-art of semi-synthetic minimal cell (SSMC technology and introduced, for the first time, the idea of chemical communication between synthetic cells and natural cells. The development of a proper synthetic communication protocol should be seen as a tool for the nascent field of bio/chemical-based Information and Communication Technologies (bio-chem-ICTs and ultimately aimed at building soft-wet-micro-robots. In this contribution (WIVACE, 2013 we present a blueprint for realizing this project, and show some preliminary experimental results. We firstly discuss how our research goal (based on the natural capabilities of biological systems to manipulate chemical signals finds a proper place in the current scientific and technological contexts. Then, we shortly comment on the experimental approaches from the viewpoints of (i synthetic cell construction, and (ii bioengineering of microorganisms, providing up-to-date results from our laboratory. Finally, we shortly discuss how autopoiesis can be used as a theoretical framework for defining synthetic minimal life, minimal cognition, and as bridge between synthetic biology and artificial intelligence.

  11. Reassigning the Structures of Natural Products Using NMR Chemical Shifts Computed with Quantum Mechanics: A Laboratory Exercise

    Science.gov (United States)

    Palazzo, Teresa A.; Truong, Tiana T.; Wong, Shirley M. T.; Mack, Emma T.; Lodewyk, Michael W.; Harrison, Jason G.; Gamage, R. Alan; Siegel, Justin B.; Kurth, Mark J.; Tantillo, Dean J.

    2015-01-01

    An applied computational chemistry laboratory exercise is described in which students use modern quantum chemical calculations of chemical shifts to assign the structure of a recently isolated natural product. A pre/post assessment was used to measure student learning gains and verify that students demonstrated proficiency of key learning…

  12. Natural Populations of Shipworm Larvae Are Attracted to Wood by Waterborne Chemical Cues

    Science.gov (United States)

    Toth, Gunilla B.; Larsson, Ann I.; Jonsson, Per R.; Appelqvist, Christin

    2015-01-01

    The life cycle of many sessile marine invertebrates includes a dispersive planktonic larval stage whose ability to find a suitable habitat in which to settle and transform into benthic adults is crucial to maximize fitness. To facilitate this process, invertebrate larvae commonly respond to habitat-related chemical cues to guide the search for an appropriate environment. Furthermore, small-scale hydrodynamic conditions affect dispersal of chemical cues, as well as swimming behavior of invertebrate larvae and encounter with potential habitats. Shipworms within the family Teredinidae are dependent on terrestrially derived wood in order to complete their life cycle, but very little is known about the cues and processes that promote settlement. We investigated the potential for remote detection of settling substrate via waterborne chemical cues in teredinid larvae through a combination of empirical field and laboratory flume experiments. Natural populations of teredinid larvae were significantly more abundant close to wooden structures enclosed in plankton net compared to empty control nets, clearly showing that shipworm larvae can sense and respond to chemical cues associated with suitable settling substrate in the field. However, the flume experiments, using ecologically relevant flow velocities, showed that the boundary layer around experimental wooden panels was thin and that the mean flow velocity exceeded larval swimming velocity approximately 5 mm (≈ 25 larval body lengths) from the panel surface. Therefore, we conclude that the scope for remote detection of waterborne cues is limited and that the likely explanation for the higher abundance of shipworm larvae associated with the wooden panels in the field is a response to a cue during or after attachment on, or very near, the substrate. Waterborne cues probably guide the larva in its decision to remain attached and settle, or to detach and continue swimming and drifting until the next encounter with a solid

  13. Natural populations of shipworm larvae are attracted to wood by waterborne chemical cues.

    Directory of Open Access Journals (Sweden)

    Gunilla B Toth

    Full Text Available The life cycle of many sessile marine invertebrates includes a dispersive planktonic larval stage whose ability to find a suitable habitat in which to settle and transform into benthic adults is crucial to maximize fitness. To facilitate this process, invertebrate larvae commonly respond to habitat-related chemical cues to guide the search for an appropriate environment. Furthermore, small-scale hydrodynamic conditions affect dispersal of chemical cues, as well as swimming behavior of invertebrate larvae and encounter with potential habitats. Shipworms within the family Teredinidae are dependent on terrestrially derived wood in order to complete their life cycle, but very little is known about the cues and processes that promote settlement. We investigated the potential for remote detection of settling substrate via waterborne chemical cues in teredinid larvae through a combination of empirical field and laboratory flume experiments. Natural populations of teredinid larvae were significantly more abundant close to wooden structures enclosed in plankton net compared to empty control nets, clearly showing that shipworm larvae can sense and respond to chemical cues associated with suitable settling substrate in the field. However, the flume experiments, using ecologically relevant flow velocities, showed that the boundary layer around experimental wooden panels was thin and that the mean flow velocity exceeded larval swimming velocity approximately 5 mm (≈ 25 larval body lengths from the panel surface. Therefore, we conclude that the scope for remote detection of waterborne cues is limited and that the likely explanation for the higher abundance of shipworm larvae associated with the wooden panels in the field is a response to a cue during or after attachment on, or very near, the substrate. Waterborne cues probably guide the larva in its decision to remain attached and settle, or to detach and continue swimming and drifting until the next

  14. Effects of natural and chemically synthesized furanones on quorum sensing in Chromobacterium violaceum

    Science.gov (United States)

    Martinelli, Daniel; Grossmann, Gilles; Séquin, Urs; Brandl, Helmut; Bachofen, Reinhard

    2004-01-01

    Background Cell to cell signaling systems in Gram-negative bacteria rely on small diffusible molecules such as the N-acylhomoserine lactones (AHL). These compounds are involved in the production of antibiotics, exoenzymes, virulence factors and biofilm formation. They belong to the class of furanone derivatives which are frequently found in nature as pheromones, flavor compounds or secondary metabolites. To obtain more information on the relation between molecular structure and quorum sensing, we tested a variety of natural and chemically synthesized furanones for their ability to interfere with the quorum sensing mechanism using a quantitative bioassay with Chromobacterium violaceum CV026 for antagonistic and agonistic action. We were looking at the following questions: 1. Do these compounds affect growth? 2) Do these compounds activate the quorum sensing system of C. violaceum CV026? 3) Do these compounds inhibit violacein formation induced by the addition of the natural inducer N-hexanoylhomoserine lactone (HHL)? 4) Do these compounds enhance violacein formation in presence of HHL? Results The naturally produced N-acylhomoserine lactones showed a strong non-linear concentration dependent influence on violacein production in C. violaceum with a maximum at 3.7*10-8 M with HHL. Apart from the N-acylhomoserine lactones only one furanone (emoxyfurane) was found to simulate N-acylhomoserine lactone activity and induce violacein formation. The most effective substances acting negatively both on growth and quorum sensing were analogs and intermediates in synthesis of the butenolides from Streptomyces antibioticus. Conclusion As the regulation of many bacterial processes is governed by quorum sensing systems, the finding of natural and synthetic furanones acting as agonists or antagonists suggests an interesting tool to control and handle detrimental AHL induced effects. Some effects are due to general toxicity; others are explained by a competitive interaction for Lux

  15. Accuracy, Precision, and Reliability of Chemical Measurements in Natural Products Research

    Science.gov (United States)

    Betz, Joseph M.; Brown, Paula N.; Roman, Mark C.

    2010-01-01

    Natural products chemistry is the discipline that lies at the heart of modern pharmacognosy. The field encompasses qualitative and quantitative analytical tools that range from spectroscopy and spectrometry to chromatography. Among other things, modern research on crude botanicals is engaged in the discovery of the phytochemical constituents necessary for therapeutic efficacy, including the synergistic effects of components of complex mixtures in the botanical matrix. In the phytomedicine field, these botanicals and their contained mixtures are considered the active pharmaceutical ingredient (API), and pharmacognosists are increasingly called upon to supplement their molecular discovery work by assisting in the development and utilization of analytical tools for assessing the quality and safety of these products. Unlike single-chemical entity APIs, botanical raw materials and their derived products are highly variable because their chemistry and morphology depend on the genotypic and phenotypic variation, geographical origin and weather exposure, harvesting practices, and processing conditions of the source material. Unless controlled, this inherent variability in the raw material stream can result in inconsistent finished products that are under-potent, over-potent, and/or contaminated. Over the decades, natural products chemists have routinely developed quantitative analytical methods for phytochemicals of interest. Quantitative methods for the determination of product quality bear the weight of regulatory scrutiny. These methods must be accurate, precise, and reproducible. Accordingly, this review discusses the principles of accuracy (relationship between experimental and true value), precision (distribution of data values), and reliability in the quantitation of phytochemicals in natural products. PMID:20884340

  16. Cumulative internal dose of natural uranium in chemical industry workers and metal; Dosis interna acumulada de uranio natural en trabajadores de la industria quimica y del metal

    Energy Technology Data Exchange (ETDEWEB)

    Capelo, R.; Garcia, M. A.; Jara, R.; Galisteo, R.; Diaz-Santos, M.; Caballero, F. J.; Pereira, A.; Rosa, J. de la; Garcia, T.; Gomez-Ariza, J. L.; Alguacil, J.

    2011-07-01

    Natural uranium is a slightly radioactive element that decays slowly by emitting an alpha particle. If absorbed by the human body can cause health effects. For people who perform their work in the chemical/metallurgical or mining it would be the main source of exposure, while for the rest of the population's main source of exposure is usually the diet. The aim of this study was to measure the cumulative dose of uranium in chemical industry workers/metal.

  17. Chemical Nature and Turnover of Carbon Associated with Diagnostic Aggregate Fractions

    Science.gov (United States)

    Six, J.

    2004-12-01

    Recently, many studies have shown the importance of aggregation in controlling soil organic C dynamics and storage. Nevertheless, very few studies have characterized the chemical nature of aggregated associated C fractions to elucidate the origin and degree of microbial alteration of these C fractions. Here, I summarize several studies employing biomarker analyses for plant-derived lignin, bacterial-derived muramic acid, and fungal-derived glucosamine to aggregate associated C fractions. A comparison of different particulate organic matter (POM) fractions indicated that fine POM occluded within microaggregates-within-macroaggregates (mM) had the greatest amino sugar content, greatest ratio of glucosamine over muramic acid, and lowest phenolic CuO oxidation products. The latter result suggest that the fine POM is the most degraded POM fraction, which was confirmed by C isotope analyses. However, side chain oxidation of lignin compounds of fine POM was intermediate, suggesting an average microbial alteration of lignin. These results suggest a significant microbial contribution, especially fungal, to this relative older C fraction protected within the mM. Carbon and isotopic analyses of the mM confirmed that this structural unit within the soil protects C from fast decomposition and facilitates the long-term stabilization of C in undisturbed soil. Furthermore, amino sugar analyses indicated that microbial-derived C is stabilized in the mM, due primarily to a greater fungal-mediated improvement of soil structural stability and concurrent deposition of fungal-derived C. In conclusion, the characterizing the chemical nature and turnover of aggregate associated C fractions elucidated that the mM fraction plays an important role in the long term stabilization of C and seems to be an ideal indicator or diagnostic fraction for C sequestration potential in soils.

  18. Crayfish can distinguish between natural and chemical stimuli as assessed by cardiac and locomotor reactions.

    Science.gov (United States)

    Kuklina, Iryna; Ložek, Filip; Císař, Petr; Kouba, Antonín; Kozák, Pavel

    2018-01-06

    In this study, cardiac and locomotor activities of signal crayfish Pacifastacus leniusculus were investigated under exposure to a range of natural (i.e., odors of conspecific crayfish, predatory fish, food, and injured conspecific) and one chemical (i.e., disinfectant chloramine-T) stimuli. Crayfish locomotion was simultaneously initiated with an increase in heart rate only when affected by chloramine-T, while locomotor response was delayed in all cases (or was not manifested at all by some specimens) when disturbed by the natural stressors. The heart rate differences measured before and during the stimulation were arranged as follows: odor of conspecific crayfish (9.2 ± 7.1%) chloramine-T (41.1 ± 14.7%) < injured conspecific (51.8 ± 28.4%). Analysis of the peculiarities of crayfish heartbeat under exposure to the tested stimuli revealed complex cardiac responses as was previously observed by an electrocardiography approach, that is, a slowed heart rate followed by a delayed increase. Evaluation of the intrinsic parameters of crayfish bioindicators remains essential due to the possibility of detection of the substantial ethological responses even in motionless animals. The role and appropriateness of signal crayfish as a bioindicator of water quality is discussed; they seem to be an applicable species for this task due to their sufficient sensitivity and broad availability. In addition to providing a better understanding of stereotypic crayfish behaviors induced by common and chemical stressors, the results of this study may serve as reference data for the evaluation of crayfish suitability for water quality tests.

  19. Hydrophobic properties and chemical characterisation of natural water repellent materials in Australian sands

    Science.gov (United States)

    Franco, C. M. M.; Clarke, P. J.; Tate, M. E.; Oades, J. M.

    2000-05-01

    Water-repellency in non-wetting sands is due to hydrophobic waxes present on the surface of sand grains and contained in particulate organic matter present in these sands. This study investigates the physico-chemical characteristics of these natural waxes and compares them to waxes extracted from potential original source materials. Non-polar and polar hydrophobic wax extracts were obtained from whole non-wetting sand, and its individual constituents, and associated organic matter. These included the sand fraction, the intrinsic particulate organic matter, tree litter, eucalyptus leaves, bark, lucerne and lupin plants, and fungi and actinomycetes isolated from these sands. Waxes were characterised for their hydrophobic properties and composition of their chemical constituents. The hydrophobicities of the waxes were assessed by measuring the water-repellency induced after treating acid washed sand with wax extracts. Non-polar and polar wax extracts of the tree litter displayed hydrophobic properties that were similar to the corresponding waxes isolated from non-wetting sand and intrinsic particulate organic matter. Unlike these plant-derived waxes, the microbial wax extracts possessed different hydrophobic properties. Characterisation of the components of the extracted waxes by gas chromatography-mass spectroscopy (GC-MS) analysis revealed a strong similarity in the composition of waxes isolated from non-wetting sand, tree litter and other plant material. The major components found were unbranched and branched C16 to C36 fatty acids and their esters, alkanes, phytanols, phytanes, and sterols. Some of these components were not detected in the microbial waxes. Unextracted samples, as well as wax extracts of non-wetting sand, intrinsic particulate organic matter, tree litter and fresh plant material were further analysed by solution and solid state Nuclear Magnetic Resonance spectroscopy which revealed the relative content of the different chemical species present.

  20. Microbiological and chemical profiles of naturally fermented table olives and brines from different Italian cultivars.

    Science.gov (United States)

    Tofalo, Rosanna; Schirone, Maria; Perpetuini, Giorgia; Angelozzi, Giovanni; Suzzi, Giovanna; Corsetti, Aldo

    2012-06-01

    Six naturally fermented (Greek-style) table olives of cultivars Itrana, Peranzana, Cellina di Nardò, Nocellara del Belice and Bella di Cerignola, as well as their corresponding brines, were studied by a combined strategy consisting of chemical, microbiological and molecular analyses. In particular, organic acids, sugars, polyphenols, fatty acids, biogenic amines and cultivable microbiota were detected by standard methods. Moreover, tyramine and histamine producing bacteria were evaluated by an original approach consisting of Reverse-Transcription (RT)-qPCR. At the end of the fermentation process, mesophilic lactobacilli and yeasts in brine represented the dominating biota, ranging from 6.25 to 7.84 log CFU/ml and from 6.5 to 7.56 log CFU/ml, respectively. Enterobacteriaceae and pathogens were undetectable in all the samples. In general, table olive preparations differed in chemical composition. In particular, C16:0 and C18:2c9,12 concentrations ranged from 9.9 to 18.8 % and from 5.4 to 15.4 % of total fatty acids, respectively. The main fatty acid detected was C18:1c9 while CLAc9, t11 was present only in traces. Polyphenol concentrations greatly differentiated the final product, depending on the cultivar. A low quantity of biogenic amines was found in some samples and biogenic amines producing bacteria were rapidly detectable by RT-qPCR.

  1. Effect of the chemical impurities on the luminescence emission of natural apatites.

    Science.gov (United States)

    Roman-Lopez, J; Correcher, V; Garcia-Guinea, J; Prado-Herrero, P; Rivera, T; Lozano, I B

    2014-05-21

    This paper reports on both cathodoluminescence (CL) and blue thermoluminescence (TL) emission of well-characterized natural Spanish and Brazilian apatites [Ca5(PO4)3(OH, F, Cl)]. Chemical analyses performed by means of Electron Microprobe Analysis (EMPA) have shown the presence of trace elements that can induce CL bands. In this sense, the apatites shown emission bands peaked at 3.26, 2.86, 2.62, 2.14, 2.02 and 1.94eV are respectively linked to substitutional Ce(3+), Tb(3+), Dy(3+), Pr(3+), Sm(3+) and Mn(2+) in structural Ca(2+) positions. The 3.18eV emission band can be associated with intrinsic electron defects on oxygen of the phosphate group (PO4)(3-). The presence of (UO2)(2+) gives rise to an emission at 2.14eV. All the studied aliquots exhibit one single UV-blue TL peak that modifies the position from one sample to another (370, 256 and 268°C) probably due to (i) the variation in the crystallinity index (from 0.88 to 1.34) and (ii) successive chemical processes such as oxidation, dehydration, dehydroxylation, and fluorine ions losses due to the thermal readout. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Spin-orbit ZORA and four-component Dirac-Coulomb estimation of relativistic corrections to isotropic nuclear shieldings and chemical shifts of noble gas dimers

    DEFF Research Database (Denmark)

    Jankowska, Marzena; Kupka, Teobald; Stobiński, Leszek

    2016-01-01

    Hartree-Fock and density functional theory with the hybrid B3LYP and general gradient KT2 exchange-correlation functionals were used for non-relativistic and relativistic nuclear magnetic shielding calculations of helium, neon, argon, krypton and xenon dimers and free atoms. Relativistic correcti......Hartree-Fock and density functional theory with the hybrid B3LYP and general gradient KT2 exchange-correlation functionals were used for non-relativistic and relativistic nuclear magnetic shielding calculations of helium, neon, argon, krypton and xenon dimers and free atoms. Relativistic...... shieldings and chemical shifts are combined with non-relativistic CCSD(T) calculations using the very large polarization-consistent basis sets aug-pcSseg-4 for He, Ne and Ar, aug-pcSseg-3 for Kr and the AQZP basis set for Xe. For the dimers also zero-point vibrational corrections obtained at the CCSD......(T) level with the same basis sets were added. Best estimates of the dimer chemical shifts are generated from these nuclear magnetic shieldings and the relative importance of electron correlation, zero-point vibrational and relativistic corrections for the shieldings and chemical shifts is analyzed....

  3. Extracting chemical information from spectral data with multiplicative light scattering effects by optical path-length estimation and correction.

    Science.gov (United States)

    Chen, Zeng-Ping; Morris, Julian; Martin, Elaine

    2006-11-15

    When analyzing complex mixtures that exhibit sample-to-sample variability using spectroscopic instrumentation, the variation in the optical path length, resulting from the physical variations inherent within the individual samples, will result in significant multiplicative light scattering perturbations. Although a number of algorithms have been proposed to address the effect of multiplicative light scattering, each has associated with it a number of underlying assumptions, which necessitates additional information relating to the spectra being attained. This information is difficult to obtain in practice and frequently is not available. Thus, with a view to removing the need for the attainment of additional information, a new algorithm, optical path-length estimation and correction (OPLEC), is proposed. The methodology is applied to two near-infrared transmittance spectral data sets (powder mixture data and wheat kernel data), and the results are compared with the extended multiplicative signal correction (EMSC) and extended inverted signal correction (EISC) algorithms. Within the study, it is concluded that the EMSC algorithm cannot be applied to the wheat kernel data set due to core information for the implementation of the algorithm not being available, while the analysis of the powder mixture data using EISC resulted in incorrect conclusions being drawn and hence a calibration model whose performance was unacceptable. In contrast, OPLEC was observed to effectively mitigate the detrimental effects of physical light scattering and significantly improve the prediction accuracy of the calibration models for the two spectral data sets investigated without any additional information pertaining to the calibration samples being required.

  4. Electronic structure and chemical bond nature in Cs2PuO2Cl4

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2015-01-01

    Full Text Available X-ray photoelectron spectral analysis of dicaesiumtetrachlorodioxoplutonate (Cs2PuO2Cl4 single crystal was done in the binding energy range 0-~35 eV on the basis of binding energies and structure of the core electronic shells (~35 eV-1250 eV, as well as the relativistic discrete variation calculation results for the PuO2Cl4 (D4h. This cluster reflects Pu close environment in Cs2PuO2Cl4 containing the plutonyl group PuO2. The many-body effects due to the presence of cesium and chlorine were shown to contribute to the outer valence (0-~15 eV binding energy spectral structure much less than to the inner valence (~15 eV- ~35 eV binding energy one. The filled Pu 5f electronic states were theoretically calculated and experimentally con- firmed to present in the valence band of Cs2PuO2Cl4. It corroborates the suggestion on the direct participation of the Pu 5f electrons in the chemical bond. The Pu 6p atomic orbitals were shown to participate in formation of both the inner and the outer valence molecular orbitals (bands, while the filled Pu 6p and O 2s, Cl 3s electronic shells were found to take the largest part in formation of the inner valence molecular orbitals. The composition of molecular orbitals and the sequence order in the binding energy range 0-~35 eV in Cs2PuO2Cl4 were established. The quantitative scheme of molecular orbitals for Cs2PuO2Cl4 in the binding energy range 0-~15 eV was built on the basis of the experimental and theoretical data. It is fundamental for both understanding the chemical bond nature in Cs2PuO2Cl4 and the interpretation of other X-ray spectra of Cs2PuO2Cl4. The contributions to the chemical binding for the PuO2Cl4 cluster were evaluated to be: the contribution of the outer valence molecular orbitals -66 %, the contribution of the inner valence molecular orbitals -34 %.

  5. Chemical buffering in natural and engineered barrier systems: Thermodynamic constraints and performance assessment consequences

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, R.C.; Wei Zhou [Monitor Scientific, LLC, Denver, CO (United States)

    2000-12-01

    Thermodynamic and kinetic constraints on the chemical buffering properties of natural and engineered-barrier systems are derived in this study from theoretical descriptions, incorporated in the reaction-path model, of reversible and irreversible mass transfer in multicomponent, multiphase systems. The buffering properties of such systems are conditional properties because they refer to a specific aqueous species in a system that is open with respect to a specific reactant. The solution to a mathematical statement of this concept requires evaluation of the dependence of the activity of the buffered species on incremental changes in the overall reaction-progress variable. This dependence can be represented by a truncated Taylor's series expansion, where the values of associated derivatives are calculated using finite-difference techniques and mass-balance, charge-balance and mass-action constraints. Kinetic constraints on buffering behavior can also be described if the relation between reactant flux and reaction rate is well defined. This relation is explicit for the important case of advective groundwater flow and water-rock interaction. We apply the theoretical basis of the chemical buffering concept to processes that could affect the performance of a deep geologic repository for nuclear waste. Specifically, we focus on the likelihood that an inverse relation must exist between the buffer intensity and the migration velocity of reaction fronts in systems involving advective or diffusive mass transport. A quantitative understanding of this relation would provide the basis for evaluating the potential role of chemical buffering in achieving the isolation and retardation functions, of the EBS and geosphere in a KBS-3 repository. Our preliminary evaluation of this role considers the effects of chemical buffering on the propagation velocity of a pH front in both the near- and far field. We use a geochemical modeling technique compatible with the reaction-path model

  6. Chemical features of soils in a natural forest of West Hungary

    Science.gov (United States)

    Hofmann, Eszter; Bidló, András

    2015-04-01

    The present research focuses on the chemical results of soils formed on miocene carbonate rocks in a natural forest of West Hungary. Soil profiles derived from the Szárhalom Forest, located near the Lake Fertő, next to the city of Sopron. Six soil profiles were opened and analysed in this area. In the field the following physical parameters were evaluated from the soil profiles: transition, structure, compactness, roots, skeletal percent, colour, physical assortment, concretion and soil defect. Laboratory analysis involved the measurement of acidity, particle distribution, carbonated lime content, humus content, ammonium lactate-acetic acid soluble phosphorus- and potassium content, potassium chloride soluble calcium- and magnesium content, ethylene-diamine-tetraacetic-acid (EDTA) and diethylene-triamine-pentaacetic-acid (DTPA) soluble copper-, iron-, manganese- and zinc contents. These soils formed under a hornbeam-oak forest climate mainly and under a beech forest climate diffusely. The location and climate of the sites forms a basis of the comparison of the soils with similar base rock. The formation of the acidic and humus-rich upper layer of the soil profiles is influenced by the mineral composition and the weathering of the rocks. X-ray diffraction (Philips P W3710/PW1050 type X-ray diffractometer), thermoanalytical measurements (Mettler Toledo TGA/DSC 1 type thermogravimeter) and ICP-OES (Thermo Scientific iCAP 7000 Series) were also carried out to determine the mineral composition of the soils and the content of heavy metals. The soil samples were collected with both traditional and undisturbed (using the Kubiena box) sampling methods to enable further micromorphological investigations as well. The research is supported by the "Agroclimate-2" (VKSZ_12-1-2013-0034) joint EU-national research project. Key words: Natural forest, Miocene limestone, Mineral composition, Thermal analysis, Micromorphology

  7. Ultrasound improves chemical reduction of natural contaminant microbiota and Salmonella enterica subsp. enterica on strawberries.

    Science.gov (United States)

    do Rosário, Denes Kaic Alves; da Silva Mutz, Yhan; Peixoto, Jaqueline Moreira Curtis; Oliveira, Syllas Borburema Silva; de Carvalho, Raquel Vieira; Carneiro, Joel Camilo Souza; de São José, Jackline Freitas Brilhante; Bernardes, Patrícia Campos

    2017-01-16

    New sanitization methods have been evaluated to improve food safety and food quality and to replace chlorine compounds. However, these new methods can lead to physicochemical and sensory changes in fruits and vegetables. The present study evaluated the effects of acetic acid, peracetic acid, and sodium dodecylbenzenesulfonate isolated or combined with 5min of ultrasound treatment (40kHz, 500W) on strawberry quality over 9days of storage at 8°C. The strawberry natural contaminant microbiota (molds and yeasts, mesophilic aerobic and lactic acid bacteria), physicochemical quality (pH, total titratable acidity, total soluble solids, vitamin C, and color), sensory quality (triangle test) and inactivation of Salmonella enterica subsp. enterica intentionally inoculated onto strawberries were analyzed. Ultrasound increased the effect of all chemical compounds in the reduction of aerobic mesophilic, molds and yeasts. The best treatment for those groups of microorganisms was ultrasound combined with peracetic acid (US+PA) that reduced 1.8 and 2.0logcfu/g during 9days of storage. Bactericidal effect of peracetic acid was also improved by ultrasound inactivation of S. enterica, reaching a decimal reduction of 2.1logcfu/g. Moreover, synergistic effects were observed in contaminant natural microbiota inactivation for all tested compounds during storage, without any major physicochemical or sensory alteration to the strawberries. Therefore, ultrasound treatment can improve the effect of sanitizers that are substitutes of chlorine compounds without altering the quality of strawberries during storage. Acetic acid (PubChem CID: 176); Peracetic acid (PubChem CID: 6585); Sodium dodecylbenzenesulfonate (PubChem CID: 18372154). Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Structural determinant of chemical reactivity and potential health effects of quinones from natural products.

    Science.gov (United States)

    Tu, Tingting; Giblin, Daryl; Gross, Michael L

    2011-09-19

    Although many phenols and catechols found as polyphenol natural products are antioxidants and have putative disease-preventive properties, others have deleterious health effects. One possible route to toxicity is the bioactivation of the phenolic function to quinones that are electrophilic, redox-agents capable of modifying DNA and proteins. The structure-property relationships of biologically important quinones and their precursors may help understand the balance between their health benefits and risks. We describe a mass-spectrometry-based study of four quinones produced by oxidizing flavanones and flavones. Those with a C2-C3 double bond on ring C of the flavonoid stabilize by delocalization of an incipient positive charge from protonation and render the protonated quinone particularly susceptible to nucleophilic attack. We hypothesize that the absence of this double bond is one specific structural determinant that is responsible for the ability of quinones to modify biological macromolecules. Those quinones containing a C2-C3 single bond have relatively higher aqueous stability and longer half-lives than those with a double bond at the same position; the latter have short half-lives at or below ∼1 s. Quinones with a C2-C3 double bond show little ability to depurinate DNA because they are rapidly hydrated to unreactive species. Molecular-orbital calculations support that quinone hydration by a highly structure-dependent mechanism accounts for their chemical properties. The evidence taken together support a hypothesis that those flavonoids and related natural products that undergo oxidation to quinones and are then rapidly hydrated are unlikely to damage important biological macromolecules.

  9. A Structural Determinant of Chemical Reactivity and Potential Health Effects of Quinones from Natural Products

    Science.gov (United States)

    Tu, Tingting; Giblin, Daryl; Gross, Michael L.

    2011-01-01

    Although many phenols and catechols found as polyphenol natural products are antioxidants and have putative disease-preventive properties, others have deleterious health effects. One possible route to toxicity is the bioactivation of the phenolic function to quinones that are electrophilic, redox-agents capable of modifying DNA and proteins. The structure-property relationships of biologically important quinones and their precursors may help understand the balance between their health benefits and risks. We describe a mass-spectrometry-based study of four quinones produced by oxidizing flavanones and flavones. Those with a C2-C3 double bond on ring C of the flavonoid stabilize by delocalization an incipient positive charge from protonation and render the protonated quinone particularly susceptible to nucleophilic attack. We hypothesize that the absence of this double bond is one specific structural determinant that is responsible for the ability of quinones to modify biological macromolecules. Those quinones containing a C2-C3 single bond have relative higher aqueous stability and longer half-lives than those with a double bond at the same position; the latter have short half-lives at or below ~ 1 s. Quinones with a C2-C3 double bond show little ability to depurinate DNA because they are rapidly hydrated to unreactive species. Molecular-orbital calculations support that quinone hydration by a highly structure-dependent mechanism accounts for their chemical properties. The evidence taken together support a hypothesis that those flavonoids and related natural products that undergo oxidation to quinones and are then rapidly hydrated are unlikely to damage important biological macromolecules. PMID:21721570

  10. Effect of natural and artificial drying of leaf biomassof Psidium guajava on the content and chemical composition of essential oil

    OpenAIRE

    Elizabeth Aparecida Josefi da Silva; Vanessa Paula da Silva; Cassia Cristina Fernandes Alves; José Milton Alves; Edson Luiz Souchie; Luiz Cláudio Almeida Barbosa

    2016-01-01

    Psidium guajava L. is native to Central and South America. It is widely distributed and well adapted to Brazil, a producer of essential oils rich in terpenes. The objective of this study was to evaluate the effects of natural and artificial drying on the content and chemical composition of the essential oil of guava leaves (Psidium guajava L.) grown in Rio Verde (GO). The two treatments consisted of drying fresh leaves either naturally in the shade or artificially at 40°C. Chemical compositio...

  11. Assessment of Application Technology of Natural User Interfaces in the Creation of a Virtual Chemical Laboratory

    Science.gov (United States)

    Jagodziński, Piotr; Wolski, Robert

    2015-02-01

    Natural User Interfaces (NUI) are now widely used in electronic devices such as smartphones, tablets and gaming consoles. We have tried to apply this technology in the teaching of chemistry in middle school and high school. A virtual chemical laboratory was developed in which students can simulate the performance of laboratory activities similar to those that they perform in a real laboratory. Kinect sensor was used for the detection and analysis of the student's hand movements, which is an example of NUI. The studies conducted found the effectiveness of educational virtual laboratory. The extent to which the use of a teaching aid increased the students' progress in learning chemistry was examined. The results indicate that the use of NUI creates opportunities to both enhance and improve the quality of the chemistry education. Working in a virtual laboratory using the Kinect interface results in greater emotional involvement and an increased sense of self-efficacy in the laboratory work among students. As a consequence, students are getting higher marks and are more interested in the subject of chemistry.

  12. Extraction of CYP chemical interactions from biomedical literature using natural language processing methods.

    Science.gov (United States)

    Jiao, Dazhi; Wild, David J

    2009-02-01

    This paper proposes a system that automatically extracts CYP protein and chemical interactions from journal article abstracts, using natural language processing (NLP) and text mining methods. In our system, we employ a maximum entropy based learning method, using results from syntactic, semantic, and lexical analysis of texts. We first present our system architecture and then discuss the data set for training our machine learning based models and the methods in building components in our system, such as part of speech (POS) tagging, Named Entity Recognition (NER), dependency parsing, and relation extraction. An evaluation of the system is conducted at the end, yielding very promising results: The POS, dependency parsing, and NER components in our system have achieved a very high level of accuracy as measured by precision, ranging from 85.9% to 98.5%, and the precision and the recall of the interaction extraction component are 76.0% and 82.6%, and for the overall system are 68.4% and 72.2%, respectively.

  13. Removal of chemical oxygen demand from textile wastewater using a natural coagulant

    Energy Technology Data Exchange (ETDEWEB)

    Ramavandi, Bahman [Bushehr University of Medical Sciences, Bushehr (Iran, Islamic Republic of); Farjadfard, Sima [Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2014-01-15

    A biomaterial was successfully synthesized from Plantago ovata by using an FeCl{sub 3}-induced crude extract (FCE). The potential of FCE to act as a natural coagulant was tested for the pretreatment of real textile wastewater. Tests were performed to evaluate the effects of FCE quantity, salt concentration, and wastewater pH on chemical oxygen demand (COD) reduction during a coagulation/flocculation process. Experimental results indicated that the wastewater could be effectively treated by using a coagulation/flocculation process, where the BOD{sub 5}/COD ratio of the effluent was improved to 0.48. A low coagulant dose, 1.5mg/L, achieved a high COD removal percentage, 89%, at operational conditions of neutral pH and room temperature. The experimental data revealed that the maximum COD removal occurred at water pH<8. Increasing the salt promoted the COD removal. The settling and filterability characteristics of the sludge were also studied. Scanning electron microscopy and energy dispersive spectroscopy studies were conducted to determine the sludge structure and composition, respectively. Overall, FCE as an eco-friendly biomaterial was revealed to be a very efficient coagulant and a promising option for the removal of COD from wastewaters.

  14. Challenges and perspectives of chemical biology, a successful multidisciplinary field of natural sciences.

    Science.gov (United States)

    Rojas-Ruiz, Fernando A; Vargas-Méndez, Leonor Y; Kouznetsov, Vladimir V

    2011-03-23

    Objects, goals, and main methods as well as perspectives of chemical biology are discussed. This review is focused on the fundamental aspects of this emerging field of life sciences: chemical space, the small molecule library and chemical sensibilization (small molecule microassays).

  15. Oil Slick Fate in 3D : Predicting the influence of (natural and chemical) dispension on oil slick fate

    NARCIS (Netherlands)

    Marieke Zeinstra-Helfrich

    2016-01-01

    In certain conditions, (part of) an oil spill can disappear from the water surface through a process called natural dispersion. One available oil spill response option is to enhance this process by addition of dispersants (chemical dispersion). An informed decision for such response requires insight

  16. Changes in chemical and microbiological parameters of some varieties of Sicily olives during natural fermentation

    Directory of Open Access Journals (Sweden)

    Romeo, Flora V.

    2006-12-01

    Full Text Available The changes and features of some olive cultivars during natural fermentation in brine were examined. The cultivars were typical of Sicily: “Nocellara messinese”, “Nocellara etnea”, “Moresca”, “Ogliarola” and “Tonda iblea”. The carpological data revealed their good quality. Chemical characteristics such as reducing sugars, titratable acidity, total phenols and dry matter were also investigated. The physical and chemical changes of olives and brines throughout the process time were monitored. Sodium chloride concentration was gradually increased from 5% (w/v to 6% after 60-75 days and 7% after 90. The olives were put in brine acidified up to pH = 4. The salt concentration and pH value were necessary to favor lactic fermentation. An uniform trend of pH was measured for all the olive cultivars: a stable pH under 4.5 value was measured. The course of titratable acidity measured in fermentation brines was in  agreement with the pH trend. The concentration of total phenols in flesh olives through the brine storage and fermentation is reported and the reduction of total phenols during the brine fermentation was fast in “Tonda iblea”, “Nocellara etnea” and “Moresca” olives.To measure the degree of oleuropein disappearance, the course of hydroxytyrosol in brine was monitored. Throughout the brining period, the growth of microbial populations was revealed on selective media: lactic acid bacteria, mesophilic microorganisms, yeasts and moulds.Los cambios y las características de algunas variedades de aceitunas han sido examinados durante la fermentación natural. Las variedades estudiadas fueron las típicas de Sicilia. Las determinaciones carpológicas revelan una buena calidad de los frutos. Las características químicas (azúcares, acidez, fenoles y materia seca han sido estudiadas. El cloruro de sodio en la salmuera se aumentó gradualmente del 5% al 6% después de 60-75 días y hasta 7% después de 90 días. Las

  17. Physical-Chemical Factors Affecting the Low Quality of Natural Water in the Khibiny Massif

    Science.gov (United States)

    Mazukhina, Svetlana; Masloboev, Vladimir; Chudnenko, Konstantin; Maksimova, Viktoriia; Belkina, Natalia

    2014-05-01

    One peculiarity of the Khibiny Massif is its spatial location. Rising over 1000 m above the surrounding hilly land and thus obstructing the passage of air masses, it promotes condensation and accumulation of surface and underground water. Annual precipitation here amounts to 600-700 mm in the valleys and up to 1600 mm on mountainous plateaus. Using this water for drinking and household purposes is problematic due to excess Al and F concentrations and high pH values. Now it is known that in its profile, the Massif is represented by three hydrogeological subzones: the upper (aerated), medium and lower ones. The upper subzone spreads throughout the Massif and is affected by the local drainage network and climatic conditions. The medium subzone is permanently saturated with underground water flowing horizontally to sites of discharge at the level of local river valleys and lakes. The fissure-vein water in the lower subzone is confined to tectonic fractures and faults in the so far underexplored, deeper parts of the Massif. Being abundant, this water ascends under high pressure. At places, water has been observed spurting from as deep as 700 m, and even 960 m. In the latter case, the temperature of ascending water was higher than 18 centigrade (Hydrogeology of the USSR, V. 27, 1971). This work was undertaken to reveal the nature of the low quality of water in the Khibiny by using physical-chemical modeling (software package Selector, Chudnenko, 2010). Processes of surface and underground water formation in the Khibiny were examined within a physical-chemical model (PCM) of the "water-rock-atmosphere-hydrogen" system. In a multi-vessel model used, each vessel represented a geochemical level of the process interpreted as spatiotemporal data - ξ (Karpov, 1981). The flow reactor consisted of 4 tanks. In the first tank, water of the Kuniok River (1000 L) interacted with atmosphere and an organic substance. The resulting solution proceeded to tanks 2-4 containing with

  18. Effect of various chemical decontamination treatments on natural microflora and sensory characteristics of poultry.

    Science.gov (United States)

    del Río, Elena; Panizo-Morán, Mónica; Prieto, Miguel; Alonso-Calleja, Carlos; Capita, Rosa

    2007-04-20

    Regulation (EC) No. 853/2004 of the European Parliament and of the Council provides a legal basis permitting the use of antimicrobial treatments to remove surface contamination from poultry. This paper reports the results of research into the effects on natural microflora, pH, and sensorial characteristics achieved by dipping chicken legs (15 min, 18+/-1 degrees C) into solutions (wt/vol) of 12% trisodium phosphate (TSP), 1200 ppm acidified sodium chlorite (ASC), 2% citric acid (CA), 220 ppm peroxyacids (Inspexx 100; PA), and water. Samples were collected immediately after evisceration, subjected to the treatments listed or left untreated (control) and tested after 0, 1, 3 and 5 days of storage (3 degrees C+/-1 degrees C). For most microbial groups similar counts were observed on water-dipped and on untreated legs. All the chemical compounds were effective in reducing microbial populations throughout storage, with TSP, ASC and CA showing the strongest antimicrobial activity. The average reductions (mean+/-standard deviation) relative to untreated samples caused by chemical treatments when considering simultaneously all storage days ranged (log(10) cfu/g skin) from 0.53+/-0.83 (PA) to 1.98+/-0.62 (TSP) for mesophilic aerobic counts, from 0.11+/-0.89 (PA) to 1.27+/-1.02 (CA) (psychrotrophs), from 1.34+/-1.40 (PA) to 2.15+/-1.20 (CA) (Enterobacteriaceae), from 1.18+/-1.24 (PA) to 1.98+/-1.16 (CA) (coliforms), from 0.66+/-0.99 (PA) to 1.86+/-1.80 (TSP) (Micrococcaceae), from 0.54+/-0.74 (TSP) to 2.17+/-1.37 (CA) (enterococci), from 0.72+/-0.66 (TSP) to 2.08+/-1.60 (CA) (Brochothrix thermosphacta), from 0.78+/-1.02 (PA) to 1.99+/-0.96 (TSP) (pseudomonads), from 0.21+/-0.61 (PA) to 1.23+/-0.60 (TSP) (lactic acid bacteria), and from 1.14+/-0.89 (PA) to 1.45+/-0.61 (ASC) (moulds and yeasts). The microbial reductions throughout storage increased, decreased, or did not vary, in accordance with microbial group and chemical involved. Similar pH values were observed for

  19. Morphological/chemical imaging of demineralized dentin layer in its natural, wet state.

    Science.gov (United States)

    Wang, Yong; Yao, Xiaomei

    2010-05-01

    Measuring the structure, composition or suitability for bonding of the acid-etched dentin substrate, especially in its hydrated state, has been a formidable problem. The purpose of this study was to determine the morphological and structural profiles of the dentin demineralized layer measured in its natural wet state using environmental scanning electron microscopy (ESEM) and micro-Raman imaging. The occlusal 1/3 of the crown was removed from nine extracted, unerupted human third molars. Dentin surfaces were abraded with 600-grit SiC sandpaper under water to create smear layers. The prepared dentin surfaces were randomly selected for treatment with the self-etching agent (Adper Prompt L-Pop) or the total-etching agent 35% H(3)PO(4) gel (with/without agitation). Micro-Raman spectra and imaging were acquired at 1-1.5microm spatial resolution at positions perpendicular to the treated surfaces; since this technique is non-destructive, the same specimens were also imaged with ESEM. Specimens were kept wet throughout spectral acquisition and ESEM observations. ESEM could be used to reveal demineralized layers in acid-etched dentin, but the resolution was low and no collagen fibrils were disclosed. The detailed chemical maps/profiles of demineralized dentin layers under wet conditions could be obtained using Raman imaging. It was shown that the mineral existed in the superficial layer of all etched dentin covered with smear layers. The mineral was much easier to be removed underneath the superficial layer. The depth, degree, and profile of dentin demineralization were dependent on the types of acids (self-etching vs. total etching) and application procedures (with vs. without agitation). Most current adhesives are applied using wet bonding techniques in which the dentin is kept fully hydrated throughout the bonding. Our ability to fully characterize the hydrated, etched dentin substrates is very important for understanding bonding under in vivo conditions. 2010 Academy of

  20. Chemical generation of volatile species of copper - Optimization, efficiency and investigation of volatile species nature.

    Science.gov (United States)

    Šoukal, Jakub; Benada, Oldřich; Matoušek, Tomáš; Dědina, Jiří; Musil, Stanislav

    2017-07-18

    This work is a comprehensive study on chemical generation of volatile species (VSG) of copper for analytical atomic spectrometry. VSG was carried out in a flow injection mode in a special arrangement of the generator. Atomization in a diffusion flame atomizer (DF) with atomic absorption spectrometry detection was mostly used for VSG optimization. Inductively coupled plasma mass spectrometry (ICP-MS) was utilized to investigate generation efficiencies and feasibility of VSG system for ultratrace analysis. Concentration of individual reagents, namely of nitric acid, sodium tetrahydroborate and various reaction modifiers, was optimized with respect to generation efficiency. Triton X-100 and Antifoam B were chosen as the best combination of the modifiers owing to sixfold increase in sensitivity, decrease of tailing of measured signals and long-term repeatability. The addition of 500 μg L(-1) of Ag was found crucial to maintain identical generation efficiency at low concentrations of Cu. This phenomenon was ascribed to the change in the size of generated species. The release and generation efficiency were accurately determined as 56-58 and 31-32%, respectively. The contribution of co-generated aerosol to release and generation efficiency measured by means of Cs and Ba was found negligible, only 0.40 and 0.13%, respectively, which underlines highly efficient VSG of Cu. The nature of volatile species was investigated by various approaches. The results cannot provide the decisive evidence. However, experiments with the DF, ICP-MS and transmission electron microscopy (TEM) indicate that the generated species are not volatile in the true sense but that they are strongly associated with fine aerosol co-generated during VSG. Cu clusters or nanoparticles of very small size (< 10 nm) are presumed but the formation of metastable copper hydride cannot be conclusively excluded. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Effect of the chemical treatments on the characteristics of natural cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Sosiati, H., E-mail: hsosiati@ugm.ac.id [Nanomaterials Research Group, Integrated Research and Testing Laboratory (LPPT), Gadjah Mada University, Yogyakarta 55281 (Indonesia); Muhaimin, M.; Abdilah, P.; Wijayanti, D. A. [Department of Physics, Faculty of Mathematics and Natural of Sciences, Gadjah Mada University, Yogyakarta 55281 (Indonesia); Harsojo; Triyana, K. [Nanomaterials Research Group, Integrated Research and Testing Laboratory (LPPT), Gadjah Mada University, Yogyakarta 55281, Indonesia and Department of Physics, Faculty of Mathematics and Natural of Sciences, Gadjah Mada University, Yogyakarta 55281 (Indonesia)

    2014-09-25

    In order to characterize the morphology and size distribution of the cellulose fibers, natural cellulose from kenaf bast fibers was extracted using two chemical treatments; (1) alkali-bleaching-ultrasonic treatment and (2) alkali-bleaching-hydrolysis. Solutions of NaOH, H{sub 2}O{sub 2} and H{sub 2}SO{sub 4} were used for alkalization, bleaching and hydrolysis, respectively. The hydrolyzed fibers were centrifuged at a rotation speed of 10000 rpm for 10 min to separate the nanofibers from the microfibers. The separation was repeated in 7 steps by controlling pH of the solution in each step until neutrality was reached. Fourier transform infrared (FTIR) spectroscopy was performed on the fibers at the final step of each treatment: i.e. either ultrasonic treated- or hydrolyzed microfibers. Their FTIR spectra were compared with FTIR spectrum of a reference commercial α-cellulose. Changes in morphology and size distribution of the treated fibers were examined by scanning electron microscopy (SEM). FTIR spectra of ultrasonic treated- and hydrolyzed microfibers nearly coincided with the FTIR spectrum of commercial α-cellulose, suggesting successful extraction of cellulose. Ultrasonic treatment for 6 h resulted in a specific morphology in which cellulose nanofibers (≥100 nm) were distributed across the entire surface of cellulose microfibers (∼5 μm). Constant magnetic stirring combined with acid hydrolysis resulted in an inhomogeneous size distribution of both cellulose rods (500 nm-3 μm length, 100–200 nm diameter) and particles 100–200 nm in size. Changes in morphology of the cellulose fibers depended upon the stirring time; longer stirring time resulted in shorter fiber lengths.

  2. Evaluation of changes of decorative parameters of natural facing stone by processing of chemical and mechanical methods

    Directory of Open Access Journals (Sweden)

    Shamrai V.I.

    2016-12-01

    Full Text Available An important task of stone enterprise is management of decorative production made of natural stone. Among a number of different ways, the most common is the polishing of the stone which changing the parameters of decorative natural stone,. Therefore, the article studies methods of processing natural facing stone that affect the gloss and lightness as decorative figures. The regularities of gloss and lightness changes depending on the time polishing chrome and aluminium oxides were established. It was established that the different types of natural stone with the same textured processing have different values of gloss and lightness. The influence of chemical impregnating means to gloss and lightness of natural facing stone surface was studied and the parameters of gloss and lightness of Pokostivskiy granodiorite, according to its classification of color tone.

  3. Nature, evolution and characterisation of rhizospheric chemical exudates affecting root herbivores

    OpenAIRE

    Hiltpold Ivan; Bernklau Elisa Jo; Bjostad Louis B.; Alvarez Nadir; Miller-Struttmann Nicole E.; Lundgren Jonathan G.; Hibbard Bruce E.

    2013-01-01

    Similar to aboveground herbivores root feeding insects must locate and identify suitable resources. In the darkness of soil they mainly rely on root chemical exudations and therefore have evolved specific behaviours. Because of their impact on crop yield most of our knowledge in belowground chemical ecology is biased towards soil dwelling insect pests. Yet the increasing literature on volatile mediated interactions in the ground underpins the great importance of chemical signalling in this ec...

  4. Variation in Chemical Defense Among Natural Populations of Common Toad, Bufo bufo, Tadpoles: the Role of Environmental Factors.

    Science.gov (United States)

    Bókony, Veronika; Móricz, Ágnes M; Tóth, Zsófia; Gál, Zoltán; Kurali, Anikó; Mikó, Zsanett; Pásztor, Katalin; Szederkényi, Márk; Tóth, Zoltán; Ujszegi, János; Üveges, Bálint; Krüzselyi, Dániel; Capon, Robert J; Hoi, Herbert; Hettyey, Attila

    2016-04-01

    Defensive toxins are widespread in nature, yet we know little about how various environmental factors shape the evolution of chemical defense, especially in vertebrates. In this study we investigated the natural variation in the amount and composition of bufadienolide toxins, and the relative importance of ecological factors in predicting that variation, in larvae of the common toad, Bufo bufo, an amphibian that produces toxins de novo. We found that tadpoles' toxin content varied markedly among populations, and the number of compounds per tadpole also differed between two geographical regions. The most consistent predictor of toxicity was the strength of competition, indicating that tadpoles produced more compounds and larger amounts of toxins when coexisting with more competitors. Additionally, tadpoles tended to contain larger concentrations of bufadienolides in ponds that were less prone to desiccation, suggesting that the costs of toxin production can only be afforded by tadpoles that do not need to drastically speed up their development. Interestingly, this trade-off was not alleviated by higher food abundance, as periphyton biomass had negligible effect on chemical defense. Even more surprisingly, we found no evidence that higher predation risk enhances chemical defenses, suggesting that low predictability of predation risk and high mortality cost of low toxicity might select for constitutive expression of chemical defense irrespective of the actual level of predation risk. Our findings highlight that the variation in chemical defense may be influenced by environmental heterogeneity in both the need for, and constraints on, toxicity as predicted by optimal defense theory.

  5. Novel, cyclic heat dissipation method for the correction of natural temperature gradients in sap flow measurements. Part 1. Theory and application.

    Science.gov (United States)

    Lubczynski, Maciek W; Chavarro-Rincon, Diana; Roy, Jean

    2012-07-01

    Natural temperature gradient (NTG) can be a significant problem in thermal sap flow measurements, particularly in dry environments with sparse vegetation. To resolve this problem, we propose a novel correction method called cyclic heat dissipation (CHD) in its thermal dissipation probe (TDP) application. The CHD method is based on cyclic, switching ON/OFF power schema measurements and a three-exponential model, extrapolating measured signal to steady state thermal equilibrium. The extrapolated signal OFF represents NTG, whereas the extrapolated signal ON represents standard TDP signal, biased by NTG. Therefore, subtraction of the OFF signal from the ON signal allows defining the unbiased TDP signal, finally processed according to standard Granier calibration. The in vivo Kalahari measurements were carried out in three steps on four different tree species, first as NTG, then as standard TDP and finally in CHD mode, each step for ∼1-2 days. Afterwards, each tree was separated from its stem following modified Roberts' (1977) procedure, and CHD verification was applied. The typical NTG varying from ∼0.5 °C during night-time to -1 °C during day-time, after CHD correction, resulted in significant reduction of sap flux densities (J(p)) as compared with the standard TDP, particularly distinct for low J(p). The verification of the CHD method indicated ∼20% agreement with the reference method, largely dependent on the sapwood area estimate. The proposed CHD method offers the following advantages: (i) in contrast to any other NTG correction method, it removes NTG bias from the measured signal by using in situ, extrapolated to thermal equilibrium signal; (ii) it does not need any specific calibration making use of the standard Granier calibration; (iii) it provides a physical background to the proposed NTG correction; (iv) it allows for power savings; (v) it is not tied to TDP, and so can be adapted to other thermal methods. In its current state, the CHD data

  6. On the nature and correction of the spurious S-wise spiral galaxy winding bias in Galaxy Zoo 1

    Science.gov (United States)

    Hayes, Wayne B.; Davis, Darren; Silva, Pedro

    2017-04-01

    The Galaxy Zoo 1 catalogue displays a bias towards the S-wise winding direction in spiral galaxies, which has yet to be explained. The lack of an explanation confounds our attempts to verify the Cosmological Principle, and has spurred some debate as to whether a bias exists in the real Universe. The bias manifests not only in the obvious case of trying to decide if the universe as a whole has a winding bias, but also in the more insidious case of selecting which Galaxies to include in a winding direction survey. While the former bias has been accounted for in a previous image-mirroring study, the latter has not. Furthermore, the bias has never been corrected in the GZ1 catalogue, as only a small sample of the GZ1 catalogue was reexamined during the mirror study. We show that the existing bias is a human selection effect rather than a human chirality bias. In effect, the excess S-wise votes are spuriously 'stolen' from the elliptical and edge-on-disc categories, not the Z-wise category. Thus, when selecting a set of spiral galaxies by imposing a threshold T so that max (PS, PZ) > T or PS + PZ > T, we spuriously select more S-wise than Z-wise galaxies. We show that when a provably unbiased machine selects which galaxies are spirals independent of their chirality, the S-wise surplus vanishes, even if humans still determine the chirality. Thus, when viewed across the entire GZ1 sample (and by implication, the Sloan catalogue), the winding direction of arms in spiral galaxies as viewed from Earth is consistent with the flip of a fair coin.

  7. 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

  8. Chemical composition and natural durability of juvenile and mature heartwood of Robinia pseudoacacia L.

    Directory of Open Access Journals (Sweden)

    João V.F Latorraca

    2011-09-01

    Full Text Available The aim of this study was to characterize the properties of juvenile and mature heartwood of Robinia pseudoacacia L. (black locust. The content, the composition, and subcellular localization of heartwood extractives were studied in 14 old-grown trees from forest sites in Germany and Hungary, as well as in 16 younger trees of four clone types. Heartwood extractives (methanol and acetone extraction were analysed by HPLC-chromatography. UV microspectrophotometry was used to localize the extractives in the wood cell walls. The natural durability of juvenile and mature heartwood was analysed according to the European standard EN 350-1. Growth analyses, as well as the chemical analyses, showed that in Robinia the formation of juvenile wood is restricted to the first 10-15 years of cambial growth. In the heartwood high contents of phenolic compounds and flavonoids were present, which were in high concentrations in the cell walls of the axial parenchyma and of the vessels. In the juvenile heartwood, the content of these extractives is significantly lower than in the mature heartwood. In agree, the juvenile heartwood had a lower resistance to decay by Coniophora puteana (brown rot fungus and Coriolus versicolor (white rot fungus compared to the mature.O objetivo deste estudo foi caracterizar as propriedades da região de cerne dos lenhos juvenis e adultos de Robinia pseudoacacia L. O conteúdo, a composição, bem como a localização subcelular dos extrativos foram estudados em 14 árvores de florestas de produção na Alemanha e na Hungria, assim como em 16 árvores de quatro tipos clone. Os extrativos (metanol e acetona extração foram analisados por cromatografia-HPLC. O microespectrofotômetro de ultra violeta foi utilizado para localizar os extrativos nas paredes celulares da madeira. A durabilidade natural do lenho juvenil e adulto foi analisada de acordo com a norma europeia EN 350-1. Análises do incremento, bem como as análises qu

  9. Survey of naturally and conventionally cured commercial frankfurters, ham, and bacon for physio-chemical characteristics that affect bacterial growth.

    Science.gov (United States)

    Sullivan, Gary A; Jackson-Davis, Armitra L; Schrader, Kohl D; Xi, Yuan; Kulchaiyawat, Charlwit; Sebranek, Joseph G; Dickson, James S

    2012-12-01

    Natural and organic food regulations preclude the use of sodium nitrite/nitrate and other antimicrobials for processed meat products. Consequently, processors have begun to use natural nitrate/nitrite sources, such as celery juice/powder, sea salt, and turbinado sugar, to manufacture natural and organic products with cured meat characteristics but without sodium nitrite. The objective of this study was to compare physio-chemical characteristics that affect Clostridium perfringens and Listeria monocytogenes growth in naturally cured and traditionally cured commercial frankfurters, hams, and bacon. Correlations of specific product characteristics to pathogen growth varied between products and pathogens, though water activity, salt concentration, and product composition (moisture, protein and fat) were common intrinsic factors correlated to pathogen growth across products. Other frequently correlated traits were related to curing reactions such as % cured pigment. Residual nitrite and nitrate were significantly correlated to C. perfringens growth but only for the ham products. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Demand for natural gas from industries in Brazil: an estimate of the price elasticity, income elasticity and forecast for 2008-2012 using VEC (Vector Error Correction) Model; Demanda por gas natural no Brasil: um estudo sobre as elasticidades preco e renda de longo prazo do segmento industrial e estimativa para o periodo de 2008-2012 usando modelo VEC (Vector Error Correction)

    Energy Technology Data Exchange (ETDEWEB)

    Cabral, Renata [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Economia e Administracao; Parente, Virginia [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Eletrotecnica e Energia

    2008-07-01

    The purpose of the present study is to estimate the long-run elasticities - manly price and income - of the demand for gas natural in the industrial category. After determining that the series under study were non-stationary, we chose to use the cointegration approach, estimating a Vector Error Correction Model (VEC Model). The obtained results show that the price elasticity for industrial sector in Brazil is higher than income elasticity. Although both of then is near to one, the price elasticity is higher that one unit while income elasticity is slightly lower. Predictions for the gas natural consumption in Brazil for industrials for 2008-2012 period are also made. (author)

  11. SURFACE CHEMICAL EFFECTS ON COLLOID STABILITY AND TRANSPORT THROUGH NATURAL POROUS MEDIA

    Science.gov (United States)

    Surface chemical effects on colloidal stability and transport through porous media were investigated using laboratory column techniques. Approximately 100 nm diameter, spherical, iron oxide particles were synthesized as the mobile colloidal phase. The column packing material was ...

  12. Chemical tracers in archaeological and natural gold: Aliseda Tartessos treasure and new discovered nuggets (SW Spain)

    National Research Council Canada - National Science Library

    Garcia-Guinea, J; Correcher, V; Rojas, R M; Fierro, J L. G; Fernandez-Martin, C; López-Arce, P; Rovira-Llorens, S

    2005-01-01

    ...), thermoluminescence (TL), X-ray photoelectron spectrometry (XPS) and electron microprobe analyses (EMPA). Pieces of Aliseda treasure and the picked gold nuggets show a highly homogeneous chemical composition of trace elements namely...

  13. Identifying the nature of surface chemical modification for directed self-assembly of block copolymers

    Directory of Open Access Journals (Sweden)

    Laura Evangelio

    2017-09-01

    Full Text Available In recent years, block copolymer lithography has emerged as a viable alternative technology for advanced lithography. In chemical-epitaxy-directed self-assembly, the interfacial energy between the substrate and each block copolymer domain plays a key role on the final ordering. Here, we focus on the experimental characterization of the chemical interactions that occur at the interface built between different chemical guiding patterns and the domains of the block copolymers. We have chosen hard X-ray high kinetic energy photoelectron spectroscopy as an exploration technique because it provides information on the electronic structure of buried interfaces. The outcome of the characterization sheds light onto key aspects of directed self-assembly: grafted brush layer, chemical pattern creation and brush/block co-polymer interface.

  14. Chemical Editing of Macrocyclic Natural Products and Kinetic Profiling Reveal Slow, Tight-Binding Histone Deacetylase Inhibitors with Picomolar Affinities

    DEFF Research Database (Denmark)

    Kitir, Betül; Maolanon, Alex R.; Ohm, Ragnhild G.

    2017-01-01

    Histone deacetylases (HDACs) are validated targets for treatment of certain cancer types and play numerous regulatory roles in biology, ranging from epigenetics to metabolism. Small molecules are highly important as tool compounds for probing these mechanisms as well as for the development of new...... medicines. Therefore, detailed mechanistic information and precise characterization of the chemical probes used to investigate the effects of HDAC enzymes are vital. We interrogated Nature's arsenal of macrocyclic nonribosomal peptide HDAC inhibitors by chemical synthesis and evaluation of more than 30...... natural products and analogues. This furnished surprising trends in binding affinities for the various macrocycles, which were then exploited for the design of highly potent class I and IIb HDAC inhibitors. Furthermore, thorough kinetic investigation revealed unexpected inhibitory mechanisms of important...

  15. Oxidative regeneration of toluene-saturated natural zeolite by gaseous ozone: The influence of zeolite chemical surface characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Alejandro, Serguei [Laboratorio de Tecnologías Limpias (F. Ingeniería), Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción (Chile); Núcleo de Energías Renovables (F. Ingeniería), Universidad Católica de Temuco, Rudecindo Ortega 02950, Temuco (Chile); Valdés, Héctor, E-mail: hvaldes@ucsc.cl [Laboratorio de Tecnologías Limpias (F. Ingeniería), Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción (Chile); Manéro, Marie-Hélène [Université de Toulouse (France); INPT, UPS (France); Laboratoire de Génie Chimique, 4, Allée Emile Monso, F–31030 Toulouse (France); CNRS (France); Laboratoire de Génie Chimique, F–31030 Toulouse (France); Zaror, Claudio A. [Departamento de Ingeniería Química (F. Ingeniería), Universidad de Concepción, Concepción, Correo 3, Casilla 160–C (Chile)

    2014-06-01

    Highlights: • Surface acidity of modified natural zeolite is related to its chemical reactivity. • Brønsted acid sites are associated to toluene adsorption. • Lewis acid sites could decompose ozone generating surface active oxygen species. • Infrared spectra evidence active atomic oxygen and oxidation by-product formation. • 2NH4Z1 sample shows the highest reactivity toward adsorbed toluene. - Abstract: In this study, the effect of zeolite chemical surface characteristics on the oxidative regeneration of toluene saturated-zeolite samples is investigated. A Chilean natural zeolite (53% clinoptilolite, 40% mordenite and 7% quartz) was chemically modified by acid treatment with hydrochloric acid and by ion-exchange with ammonium sulphate. Thermal pre-treatments at 623 and 823 K were applied and six zeolite samples with different chemical surface characteristics were generated. Chemical modification of natural zeolite followed by thermal out-gassing allows distinguishing the role of acidic surface sites on the regeneration of exhausted zeolites. An increase in Brønsted acid sites on zeolite surface is observed as a result of ammonium-exchange treatment followed by thermal treatment at 623 K, thus increasing the adsorption capacity toward toluene. High ozone consumption could be associated to a high content of Lewis acid sites, since these could decompose ozone into atomic active oxygen species. Then, surface oxidation reactions could take part among adsorbed toluene at Brønsted acid sites and surface atomic oxygen species, reducing the amount of adsorbed toluene after the regenerative oxidation with ozone. Experimental results show that the presence of adsorbed oxidation by-products has a negative impact on the recovery of zeolite adsorption capacity.

  16. Total synthesis approaches to natural product derivatives based on the combination of chemical synthesis and metabolic engineering.

    Science.gov (United States)

    Kirschning, Andreas; Taft, Florian; Knobloch, Tobias

    2007-10-21

    Secondary metabolites are an extremely diverse and important group of natural products with industrial and biomedical implications. Advances in metabolic engineering of both native and heterologous secondary metabolite producing organisms have allowed the directed synthesis of desired novel products by exploiting their biosynthetic potentials. Metabolic engineering utilises knowledge of cellular metabolism to alter biosynthetic pathways. An important technique that combines chemical synthesis with metabolic engineering is mutasynthesis (mutational biosynthesis; MBS), which advanced from precursor-directed biosynthesis (PDB). Both techniques are based on the cellular uptake of modified biosynthetic intermediates and their incorporation into complex secondary metabolites. Mutasynthesis utilises genetically engineered organisms in conjunction with feeding of chemically modified intermediates. From a synthetic chemist's point of view the concept of mutasynthesis is highly attractive, as the method combines chemical expertise with Nature's synthetic machinery and thus can be exploited to rapidly create small libraries of secondary metabolites. However, in each case, the method has to be critically compared with semi- and total synthesis in terms of practicability and efficiency. Recent developments in metabolic engineering promise to further broaden the scope of outsourcing chemically demanding steps to biological systems.

  17. Endocrine-Disrupting Chemicals and Oil and Natural Gas Operations: Potential Environmental Contamination and Recommendations to Assess Complex Environmental Mixtures.

    Science.gov (United States)

    Kassotis, Christopher D; Tillitt, Donald E; Lin, Chung-Ho; McElroy, Jane A; Nagel, Susan C

    2016-03-01

    Hydraulic fracturing technologies, developed over the last 65 years, have only recently been combined with horizontal drilling to unlock oil and gas reserves previously deemed inaccessible. Although these technologies have dramatically increased domestic oil and natural gas production, they have also raised concerns for the potential contamination of local water supplies with the approximately 1,000 chemicals that are used throughout the process, including many known or suspected endocrine-disrupting chemicals. We discuss the need for an endocrine component to health assessments for drilling-dense regions in the context of hormonal and antihormonal activities for chemicals used. We discuss the literature on a) surface and groundwater contamination by oil and gas extraction operations, and b) potential human exposure, particularly in the context of the total hormonal and antihormonal activities present in surface and groundwater from natural and anthropogenic sources; we also discuss initial analytical results and critical knowledge gaps. In light of the potential for environmental release of oil and gas chemicals that can disrupt hormone receptor systems, we recommend methods for assessing complex hormonally active environmental mixtures. We describe a need for an endocrine-centric component for overall health assessments and provide information supporting the idea that using such a component will help explain reported adverse health trends as well as help develop recommendations for environmental impact assessments and monitoring programs.

  18. Oxidative regeneration of toluene-saturated natural zeolite by gaseous ozone: the influence of zeolite chemical surface characteristics.

    Science.gov (United States)

    Alejandro, Serguei; Valdés, Héctor; Manéro, Marie-Hélène; Zaror, Claudio A

    2014-06-15

    In this study, the effect of zeolite chemical surface characteristics on the oxidative regeneration of toluene saturated-zeolite samples is investigated. A Chilean natural zeolite (53% clinoptilolite, 40% mordenite and 7% quartz) was chemically modified by acid treatment with hydrochloric acid and by ion-exchange with ammonium sulphate. Thermal pre-treatments at 623 and 823K were applied and six zeolite samples with different chemical surface characteristics were generated. Chemical modification of natural zeolite followed by thermal out-gassing allows distinguishing the role of acidic surface sites on the regeneration of exhausted zeolites. An increase in Brønsted acid sites on zeolite surface is observed as a result of ammonium-exchange treatment followed by thermal treatment at 623K, thus increasing the adsorption capacity toward toluene. High ozone consumption could be associated to a high content of Lewis acid sites, since these could decompose ozone into atomic active oxygen species. Then, surface oxidation reactions could take part among adsorbed toluene at Brønsted acid sites and surface atomic oxygen species, reducing the amount of adsorbed toluene after the regenerative oxidation with ozone. Experimental results show that the presence of adsorbed oxidation by-products has a negative impact on the recovery of zeolite adsorption capacity. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Endocrine-disrupting chemicals and oil and natural gas operations: Potential environmental contamination and recommendations to assess complex environmental mixtures

    Science.gov (United States)

    Kassotis, Christopher D.; Tillitt, Donald E.; Lin, Chung-Ho; McElroy, Jane A.; Nagel, Susan C.

    2016-01-01

    Background: Hydraulic fracturing technologies, developed over the last 65 years, have only recently been combined with horizontal drilling to unlock oil and gas reserves previously deemed inaccessible. While these technologies have dramatically increased domestic oil and natural gas production, they have also raised concerns for the potential contamination of local water supplies with the approximately 1,000 chemicals used throughout the process, including many known or suspected endocrine-disrupting chemicals.Objectives: We discuss the need for an endocrine component to health assessments for drilling-dense regions in the context of hormonal and anti-hormonal activities for chemicals used.Methods: We discuss the literature on 1) surface and ground water contamination by oil and gas extraction operations, and 2) potential human exposure, particularly in context of the total hormonal and anti-hormonal activities present in surface and ground water from natural and anthropogenic sources, with initial analytical results and critical knowledge gaps discussed.Discussion: In light of the potential for environmental release of oil and gas chemicals that can disrupt hormone receptor systems, we recommend methods for assessing complex hormonally active environmental mixtures.Conclusions: We describe a need for an endocrine-centric component for overall health assessments and provide supporting information that using this may help explain reported adverse health trends as well as help develop recommendations for environmental impact assessments and monitoring programs.

  20. Effect of natural and artificial drying of leaf biomassof Psidium guajava on the content and chemical composition of essential oil

    Directory of Open Access Journals (Sweden)

    Elizabeth Aparecida Josefi da Silva

    2016-10-01

    Full Text Available Psidium guajava L. is native to Central and South America. It is widely distributed and well adapted to Brazil, a producer of essential oils rich in terpenes. The objective of this study was to evaluate the effects of natural and artificial drying on the content and chemical composition of the essential oil of guava leaves (Psidium guajava L. grown in Rio Verde (GO. The two treatments consisted of drying fresh leaves either naturally in the shade or artificially at 40°C. Chemical composition was analyzed qualitatively and quantitatively by gas coupled with mass spectrometer chromatography (GC/MS and gas chromatography using a flame ionizer (GC-FID, respectively. The method of drying changed the content and chemical composition of the essential oil of guava leaves. Drying in the shade reduced the content and altered the constituents of the essential oil, whereas drying in an oven at 40°C, despite having reduced the amounts of the constituents, exhibited the highest essential oil content and increased the concentration of certain major constituents as compared to that in the natural shade drying method. The major components found in the essential oil of leaves regardless of the drying processes were trans-caryophyllene, ?-humulene, aromadendrene, ?-selinene, and selin-11-en-4?-ol. According to reports in the literature, these compounds possess fungicidal, insecticidal, antimicrobial, and anti-inflammatory activity, among others beneficial actions.

  1. The Origin of the Natural Water Chemical Composition in the Permafrost Region of the Eastern Slope of the Polar Urals

    Directory of Open Access Journals (Sweden)

    Natalia Guseva

    2016-12-01

    Full Text Available This article presents the results of the study of water chemical composition and formation processes in the eastern slope of the Polar Ural where permafrost is widely spread. To date, this region has not been studied in detail. However, it is very important to have information on the natural waters in this region because they play a significant role in all geochemical processes, including climate formation. For this study, 107 water samples were collected from lakes, rivers and active layer waters. The studied waters are ultrafresh; total dissolved solids vary from 14 to 438 mg/L. pH ranges from 3.5 to 9.0. The chemical type of the studied waters is mostly HCO3–Ca–Mg. The geochemical environment of the studied waters contributes to the accumulation of such trace elements as Fe, Mn, Al, Ni, Au, Co, Li, Sc, Ti, Cr, Sr, Nb, Mo, Cs, La, Eu, Lu, Hg, and Se. The chemical composition peculiarities of active layer waters, rivers, lakes and waters of stone pits and exploration trenches and the description of their chemical composition formation processes are given in the present study. The water–rock interaction is a dominant process of water chemical composition formation in the studied region. The obtained results have both potential theoretical and practical applications.

  2. Communication: An improved linear scaling perturbative triples correction for the domain based local pair-natural orbital based singles and doubles coupled cluster method [DLPNO-CCSD(T)].

    Science.gov (United States)

    Guo, Yang; Riplinger, Christoph; Becker, Ute; Liakos, Dimitrios G; Minenkov, Yury; Cavallo, Luigi; Neese, Frank

    2018-01-07

    In this communication, an improved perturbative triples correction (T) algorithm for domain based local pair-natural orbital singles and doubles coupled cluster (DLPNO-CCSD) theory is reported. In our previous implementation, the semi-canonical approximation was used and linear scaling was achieved for both the DLPNO-CCSD and (T) parts of the calculation. In this work, we refer to this previous method as DLPNO-CCSD(T0) to emphasize the semi-canonical approximation. It is well-established that the DLPNO-CCSD method can predict very accurate absolute and relative energies with respect to the parent canonical CCSD method. However, the (T0) approximation may introduce significant errors in absolute energies as the triples correction grows up in magnitude. In the majority of cases, the relative energies from (T0) are as accurate as the canonical (T) results of themselves. Unfortunately, in rare cases and in particular for small gap systems, the (T0) approximation breaks down and relative energies show large deviations from the parent canonical CCSD(T) results. To address this problem, an iterative (T) algorithm based on the previous DLPNO-CCSD(T0) algorithm has been implemented [abbreviated here as DLPNO-CCSD(T)]. Using triples natural orbitals to represent the virtual spaces for triples amplitudes, storage bottlenecks are avoided. Various carefully designed approximations ease the computational burden such that overall, the increase in the DLPNO-(T) calculation time over DLPNO-(T0) only amounts to a factor of about two (depending on the basis set). Benchmark calculations for the GMTKN30 database show that compared to DLPNO-CCSD(T0), the errors in absolute energies are greatly reduced and relative energies are moderately improved. The particularly problematic case of cumulene chains of increasing lengths is also successfully addressed by DLPNO-CCSD(T).

  3. Communication: An improved linear scaling perturbative triples correction for the domain based local pair-natural orbital based singles and doubles coupled cluster method [DLPNO-CCSD(T)

    KAUST Repository

    Guo, Yang

    2018-01-04

    In this communication, an improved perturbative triples correction (T) algorithm for domain based local pair-natural orbital singles and doubles coupled cluster (DLPNO-CCSD) theory is reported. In our previous implementation, the semi-canonical approximation was used and linear scaling was achieved for both the DLPNO-CCSD and (T) parts of the calculation. In this work, we refer to this previous method as DLPNO-CCSD(T0) to emphasize the semi-canonical approximation. It is well-established that the DLPNO-CCSD method can predict very accurate absolute and relative energies with respect to the parent canonical CCSD method. However, the (T0) approximation may introduce significant errors in absolute energies as the triples correction grows up in magnitude. In the majority of cases, the relative energies from (T0) are as accurate as the canonical (T) results of themselves. Unfortunately, in rare cases and in particular for small gap systems, the (T0) approximation breaks down and relative energies show large deviations from the parent canonical CCSD(T) results. To address this problem, an iterative (T) algorithm based on the previous DLPNO-CCSD(T0) algorithm has been implemented [abbreviated here as DLPNO-CCSD(T)]. Using triples natural orbitals to represent the virtual spaces for triples amplitudes, storage bottlenecks are avoided. Various carefully designed approximations ease the computational burden such that overall, the increase in the DLPNO-(T) calculation time over DLPNO-(T0) only amounts to a factor of about two (depending on the basis set). Benchmark calculations for the GMTKN30 database show that compared to DLPNO-CCSD(T0), the errors in absolute energies are greatly reduced and relative energies are moderately improved. The particularly problematic case of cumulene chains of increasing lengths is also successfully addressed by DLPNO-CCSD(T).

  4. Communication: An improved linear scaling perturbative triples correction for the domain based local pair-natural orbital based singles and doubles coupled cluster method [DLPNO-CCSD(T)

    Science.gov (United States)

    Guo, Yang; Riplinger, Christoph; Becker, Ute; Liakos, Dimitrios G.; Minenkov, Yury; Cavallo, Luigi; Neese, Frank

    2018-01-01

    In this communication, an improved perturbative triples correction (T) algorithm for domain based local pair-natural orbital singles and doubles coupled cluster (DLPNO-CCSD) theory is reported. In our previous implementation, the semi-canonical approximation was used and linear scaling was achieved for both the DLPNO-CCSD and (T) parts of the calculation. In this work, we refer to this previous method as DLPNO-CCSD(T0) to emphasize the semi-canonical approximation. It is well-established that the DLPNO-CCSD method can predict very accurate absolute and relative energies with respect to the parent canonical CCSD method. However, the (T0) approximation may introduce significant errors in absolute energies as the triples correction grows up in magnitude. In the majority of cases, the relative energies from (T0) are as accurate as the canonical (T) results of themselves. Unfortunately, in rare cases and in particular for small gap systems, the (T0) approximation breaks down and relative energies show large deviations from the parent canonical CCSD(T) results. To address this problem, an iterative (T) algorithm based on the previous DLPNO-CCSD(T0) algorithm has been implemented [abbreviated here as DLPNO-CCSD(T)]. Using triples natural orbitals to represent the virtual spaces for triples amplitudes, storage bottlenecks are avoided. Various carefully designed approximations ease the computational burden such that overall, the increase in the DLPNO-(T) calculation time over DLPNO-(T0) only amounts to a factor of about two (depending on the basis set). Benchmark calculations for the GMTKN30 database show that compared to DLPNO-CCSD(T0), the errors in absolute energies are greatly reduced and relative energies are moderately improved. The particularly problematic case of cumulene chains of increasing lengths is also successfully addressed by DLPNO-CCSD(T).

  5. Magnesium carbide synthesis from methane and magnesium oxide - a potential methodology for natural gas conversion to premium fuels and chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, A.F.; Modestino, A.J.; Howard, J.B. [Massachusetts Institute of Technology, Cambridge, MA (United States)] [and others

    1995-12-31

    Diversification of the raw materials base for manufacturing premium fuels and chemicals offers U.S. and international consumers economic and strategic benefits. Extensive reserves of natural gas in the world provide a valuable source of clean gaseous fuel and chemical feedstock. Assuming the availability of suitable conversion processes, natural gas offers the prospect of improving flexibility in liquid fuels and chemicals manufacture, and thus, the opportunity to complement, supplement, or displace petroleum-based production as economic and strategic considerations require. The composition of natural gas varies from reservoir to reservoir but the principal hydrocarbon constituent is always methane (CH{sub 4}). With its high hydrogen-to-carbon ratio, methane has the potential to produce hydrogen or hydrogen-rich products. However, methane is a very chemically stable molecule and, thus, is not readily transformed to other molecules or easily reformed to its elements (H{sub 2} and carbon). In many cases, further research is needed to augment selectivity to desired product(s), increase single-pass conversions, or improve economics (e.g. there have been estimates of $50/bbl or more for liquid products) before the full potential of these methodologies can be realized on a commercial scale. With the trade-off between gas conversion and product selectivity, a major challenge common to many of these technologies is to simultaneously achieve high methane single-pass conversions and high selectivity to desired products. Based on the results of the scoping runs, there appears to be strong indications that a breakthrough has finally been achieved in that synthesis of magnesium carbides from MgO and methane in the arc discharge reactor has been demonstrated.

  6. Enhancement of mechanical properties and interfacial adhesion by chemical odification of natural fibre reinforced polypropylene composites

    CSIR Research Space (South Africa)

    Erasmus, E

    2008-11-01

    Full Text Available Natural fibres are often used for reinforcing thermoplastics, like polypropylene, to manufacture composite materials exhibiting numerous advantages such as high mechanical properties, low density and biodegradability. The mechanical properties of a...

  7. Marine natural products: chemical and biological potential of seaweeds and their endophytic fungi

    OpenAIRE

    Ana Lígia Leandrini de Oliveira; Rafael de Felício; Hosana Maria Debonsi

    2012-01-01

    Marine natural products have currently been recognized as the most promising source of bioactive substances for drug discovery research. In this review, extraordinary metabolites from marine algae species are illustrated, as well as approaches for their isolation and determination of their biological properties and pharmaceutical potential. Furthermore, marine endophytic microorganisms (from marine algae) are presented as a new subject for extensive investigation to find novel natural product...

  8. Marine natural products: chemical and biological potential of seaweeds and their endophytic fungi

    Directory of Open Access Journals (Sweden)

    Ana Lígia Leandrini de Oliveira

    2012-06-01

    Full Text Available Marine natural products have currently been recognized as the most promising source of bioactive substances for drug discovery research. In this review, extraordinary metabolites from marine algae species are illustrated, as well as approaches for their isolation and determination of their biological properties and pharmaceutical potential. Furthermore, marine endophytic microorganisms (from marine algae are presented as a new subject for extensive investigation to find novel natural products, which make them a potentially rich and innovative source for new drug candidates.

  9. Cinnamon (Cinnamomum zeylanicum) as an antidote or a protective agent against natural or chemical toxicities: a review.

    Science.gov (United States)

    Dorri, Mahyar; Hashemitabar, Shirin; Hosseinzadeh, Hossein

    2018-01-10

    Cinnamon (Cinnamomum zeylanicum, Lauraceae) is a food additive greatly used for its taste. However, recently this medicinal plant has been brought to attention due to its medical effects. Cinnamon has constituents such as cinnamaldehyde and cinnamic acid that offers some health benefits including antioxidant and free-radical scavenging properties, lowering of blood glucose, anti-cholesterolemic, analgesic, antimicrobial, anti-inflammatory, anti-yeast, anti-secretagogue, and anti-gastric ulcer effects. This review summarizes various in vitro and animal studies on the protective effects of cinnamon against natural and chemical toxins. These studies consider the antidotal and/or protective effects of cinnamon and its major constituents against natural toxins and chemical-induced toxicities. It has been mentioned that cinnamon and its main constituents can ameliorate the toxicity of chemical toxins in liver, kidney, blood, brain, embryo, reproductive system, heart, spleen in part through antioxidant effect, radical scavenging, reducing lipid peroxidation, anti-inflammatory, fungistatic and fungicidal activities, modulation of CK-MB, LDH, TNF-α, IL-6, mitogen-activated protein kinase (MAPK), and nuclear factor-ĸB (NF-ĸB) signaling pathways.

  10. Preparing "Chameleon Balls" from Natural Plants: Simple Handmade pH Indicator and Teaching Material for Chemical Equilibrium

    Science.gov (United States)

    Kanda, Naoki; Asano, Takayuki; Itoh, Toshiyuki; Onoda, Makoto

    1995-12-01

    Anthocyanins are found in the flowers and fruits of natural plants. Since their color depends on pH, they are sometines used as a pH indicator. Since these sequences are reversible, they are also useful in demonstrating chemical equilibrium in the repetitive color changes of anthocyanins from flowers by controlling pH conditions. We prepared the polysaccharide beads conatining water extracts of red cabbage as calcium alginate. The beads showed a clear red color under acidic conditions, turned blue at neutral pH of 7, and orange-yellow at pH of 13. This color change could be demonstrated over and over. Because the color changes of these polysaccharide beads depended darmatically on pH, junior high students in science classes called them "chameleon balls" when we demonstrated this reaction for them. In this paper we describe how polysaccharide beads, which are made from calcium alginate with natural pigments, served as a teaching tool for the chemical equilibrium of anthocyanins under different pH conditions. Preparation of the chameleon ball is very easy. The most important thing is that making the chameleon ball is great fun. The ball should therefore be viewed not only as a handmade pH indicator but also an interesting teaching tool of the chemical equilibrium reaction.

  11. Effect of chemical environment on the dynamics of water confined in calcium silicate minerals: natural and synthetic tobermorite.

    Science.gov (United States)

    Monasterio, Manuel; Gaitero, Juan J; Manzano, Hegoi; Dolado, Jorge S; Cerveny, Silvina

    2015-05-05

    Confined water in the slit mesopores of the mineral tobermorite provides an excellent model system for analyzing the dynamic properties of water confined in cement-like materials. In this work, we use broadband dielectric spectroscopy (BDS) to analyze the dynamic of water entrapped in this crystalline material. Two samples, one natural and one synthetic, were analyzed, and despite their similar structure, the motion of confined water in their zeolitic cavity displays considerably different behavior. The water dynamics splits into two different behaviors depending on the chemical nature of the otherwise identical structural environment: water molecules located in areas where the primary building units are SiO4 relax slowly compared to water molecules located in cavities built with both AlO4 and SiO4. Compared to water confined in regular porous systems, water restricted in tobermorite is slower, indicating that the mesopore structure induces high disorder in the water structure. A comparison with water confined in the C-S-H gel is also discussed in this work. The strong dynamical changes in water due to the presence of aluminum might have important implications in the chemical transport of ions within hydrated calcium silicates, a process that governs the leaching and chemical degradation of cement.

  12. Structure and chemical characteristics of natural mineral deposit Terbunskaya (Lipetsk region, Russia)

    Energy Technology Data Exchange (ETDEWEB)

    Motyleva, S., E-mail: motyleva-svetlana@mail.ru; Mertvishcheva, M. [All-Russian Horticular Institute for Breeding, Agrotechnology and Nursery Russian Academy of Agricultural Sciences, Moskow (Russian Federation); Shchuchka, R.; Gulidova, V. [Yelets state university named after I. A. Bunin, Yelets (Russian Federation)

    2015-07-22

    New knowledge about the mineralogical features Terbunsky mineral. Investigated 5 fractions isolated from the incision (2-2,5 m). Terbunskaya deposit belongs to minerals Santonian age. Scanning electron microscopy and energy dispersive analysis of fractions isolated studied in detail. In the coarse fractions found ancient organic remains of algae and micro-organisms that have been sedimented together with the mineral component during geological periods. The share of organic inclusions does not exceed 1.5%. Chemical composition confirms the presence of silicon and carbonate organisms. Advantageously proportion of minerals having a layered structure with a plurality of micro and nano pore size 600 - 80-nm and an average chemical composition (wt%): Na (0,64), Mg (0,54), Al (13.48), Si (27 57), K (2.39) Ca (0.75)

  13. Application of process simulators in chemical engineering process design -natural gas separation plant case study

    Directory of Open Access Journals (Sweden)

    Stevanović Dimitrije Ž.

    2014-01-01

    Full Text Available Software for chemical processes modeling and simulation, in the past few decades, play an important role in the development of chemical-process industry with their growing capabilities and wide range of application. Usage of process simulators in Serbia for the process design is very limited. This paper gives a brief overview of the numerous process simulators that are used in the chemical-process industry today. The conceptual design is responsible for most of the investment costs in chemical process industry. Importance of precise design on preliminary level is obvious. Wrong decisions made at the conceptual level could be carried out throughout the chain in process design to the detailed design procedures and procurement of equipment. Although preliminary design phase comprises only about 2% of the total cost of the project, it contributes significantly to the reduction of cost of the project by more than 30%. Therefore process simulators play important role in elimination of unnecessary errors in basic process design. Here is also shown a case study of parallel process simulated in different process simulators which tests the results, the reliability and usefulness of these programs in solving specific engineering tasks. Comparison of given simulation results confirm that the modern process simulators are at high level of confidence, no matter they are based on different models, equations, methods, operations, interfaces or data bases. Usage of software speeds up the arrival of optimized solution during the design and the operational procedures. Therefore software have significant impact on reducing time of pre-project phase such as research, conceptual design, and proving project abilities. It’s development lead to faster commercialization of industrial ideas. [Projekat Ministartsva nauke Republike Srbije, br. TR 34009

  14. Chemical analyses of wasp-associated streptomyces bacteria reveal a prolific potential for natural products discovery

    DEFF Research Database (Denmark)

    Poulsen, Michael; Oh, Dong-Chan; Clardy, Jon

    2011-01-01

    and solitary Hymenoptera. Here we test this possibility by examining two species of solitary mud dauber wasps, Sceliphron caementarium and Chalybion californicum. We performed enrichment isolations from 33 wasps and obtained more than 200 isolates of Streptomyces Actinobacteria. Chemical analyses of 15...... and antibacterial activity. The prevalence and anti-microbial properties of Actinobacteria associated with these two solitary wasp species suggest the potential role of these Streptomyces as antibiotic-producing symbionts, potentially helping defend their wasp hosts from pathogenic microbes. Finding...

  15. Metabolomics and Natural-Products Strategies to Study Chemical Ecology in Nematodes

    Science.gov (United States)

    Edison, Arthur S.; Clendinen, Chaevien S.; Ajredini, Ramadan; Beecher, Chris; Ponce, Francesca V.; Stupp, Gregory S.

    2015-01-01

    This review provides an overview of two complementary approaches to identify biologically active compounds for studies in chemical ecology. The first is activity-guided fractionation and the second is metabolomics, particularly focusing on a new liquid chromatography–mass spectrometry-based method called isotopic ratio outlier analysis. To illustrate examples using these approaches, we review recent experiments using Caenorhabditis elegans and related free-living nematodes. PMID:26141866

  16. Evaluation of reduced chemical kinetic mechanisms used for modeling mild combustion for natural gas

    Directory of Open Access Journals (Sweden)

    Hamdi Mohamed

    2009-01-01

    Full Text Available A numerical and parametric study was performed to evaluate the potential of reduced chemistry mechanisms to model natural gas chemistry including NOx chemistry under mild combustion mode. Two reduced mechanisms, 5-step and 9-step, were tested against the GRI-Mech3.0 by comparing key species, such as NOx, CO2 and CO, and gas temperature predictions in idealized reactors codes under mild combustion conditions. It is thus concluded that the 9-step mechanism appears to be a promising reduced mechanism that can be used in multi-dimensional codes for modeling mild combustion of natural gas.

  17. Perturbing dissimilar biomolecular targets from natural product scaffolds and focused chemical decoration

    DEFF Research Database (Denmark)

    Nielsen, John; Tung, Truong Thanh; Tim, Holm Jakobsen

    2017-01-01

    agents. On first attempt, by screening natural product sources we have successfully discovered that curcuminoids as potent inhibitors of p-type ATPases from diverse kingdoms of life including Pma1. On other attempt, the fungal metabolite fusaric acid was reported to reduce stomatal conductance in banana...

  18. Chitosan-Starch Films with Natural Extracts: Physical, Chemical, Morphological and Thermal Properties

    Directory of Open Access Journals (Sweden)

    Jessica I. Lozano-Navarro

    2018-01-01

    Full Text Available The aim of this study is to analyze the properties of a series of polysaccharide composite films, such as apparent density, color, the presence of functional groups, morphology, and thermal stability, as well as the correlation between them and their antimicrobial and optical properties. Natural antioxidants such as anthocyanins (from cranberry; blueberry and pomegranate; betalains (from beetroot and pitaya; resveratrol (from grape; and thymol and carvacrol (from oregano were added to the films. Few changes in the position and intensity of the FTIR spectra bands were observed despite the low content of extract added to the films. Due to this fact, the antioxidants were extracted and identified by spectroscopic analysis; and they were also quantified using the Folin-Denis method and a gallic acid calibration curve, which confirmed the presence of natural antioxidants in the films. According to the SEM analysis, the presence of natural antioxidants has no influence on the film morphology because the stretch marks and white points that were observed were related to starch presence. On the other hand, the TGA analysis showed that the type of extract influences the total weight loss. The overall interpretation of the results suggests that the use of natural antioxidants as additives for chitosan-starch film preparation has a prominent impact on most of the critical properties that are decisive in making them suitable for food-packing applications.

  19. Ecopharmacognosy: Exploring The Chemical And Biological Potential Of Nature For Human Health

    Directory of Open Access Journals (Sweden)

    Geoffrey A. Cordell

    2014-04-01

    Full Text Available “Why didn’t they develop natural product drugs in a sustainable manner at the beginning of this century?”  In 2035, when about 10.0 billion will inhabit Earth, will this be our legacy as the world contemplates the costs and availability of synthetic and gene-based products for primary health care?  Acknowledging the recent history of the relationship between humankind and the Earth, it is essential that the health care issues being left for our descendants be considered in terms of resources. For most people in the world, there are two vast health care “gaps”, access to quality drugs and the development of drugs for major global and local diseases.  Consequently for all of these people, plants, in their various forms, remain a primary source of health care.  In the developed countries, natural products derived from plants assume a relatively minor role in health care, as prescription and over-the-counter products, even with the widespread use of phytotherapeutical preparations.  Significantly, pharmaceutical companies have retrenched substantially in their disease areas of focus.  These research areas do not include the prevalent diseases of the middle- and lower-income countries, and important diseases of the developed world, such as drug resistance. What then is the vision for natural product research to maintain the choices of drug discovery and pharmaceutical development for future generations?  In this discussion some facets of how natural products must be involved globally, in a sustainable manner, for improving health care will be examined within the framework of the new term “ecopharmacognosy”, which invokes sustainability as the basis for research on biologically active natural products.  Access to the biome, the acquisition, analysis and dissemination of plant knowledge, natural product structure diversification, biotechnology development, strategies for natural product drug discovery, and aspects of multitarget

  20. Tuning the performance of a natural treatment process using metagenomics for improved trace organic chemical attenuation

    KAUST Repository

    Drewes, Jorg

    2014-02-01

    By utilizing high-throughput sequencing and metagenomics, this study revealed how the microbial community characteristics including composition, diversity, as well as functional genes in managed aquifer recharge (MAR) systems can be tuned to enhance removal of trace organic chemicals of emerging concern (CECs). Increasing the humic content of the primary substrate resulted in higher microbial diversity. Lower concentrations and a higher humic content of the primary substrate promoted the attenuation of biodegradable CECs in laboratory and field MAR systems. Metagenomic results indicated that the metabolic capabilities of xenobiotic biodegradation were significantly promoted for the microbiome under carbon-starving conditions. © IWA Publishing 2014.

  1. Chemical composition of natural waters of contaminated area: The case for the Imandra Lake catchment (the Kola Peninsula)

    Science.gov (United States)

    Evtyugina, Z. A.; Guseva, N. V.; Kopylova, J. G.; A, Vorobeva D.

    2016-03-01

    The study of the current chemical composition of natural waters in the eastern and western parts of the Imandra Lake catchment was performed using ion chromatography, potentiometry and inductively coupled plasma mass spectrometry. It was found that the content of trace elements in the surface water is considerably higher than that in the groundwater. The nickel and copper concentrations exceed the background levels over 19 and 2 times respectively in groundwater, and 175 and 61 times in the surface waters. These data show that the Severonikel influences negatively air and surface water.

  2. Causal knowledge extraction by natural language processing in material science: a case study in chemical vapor deposition

    Directory of Open Access Journals (Sweden)

    Yuya Kajikawa

    2006-11-01

    Full Text Available Scientific publications written in natural language still play a central role as our knowledge source. However, due to the flood of publications, the literature survey process has become a highly time-consuming and tangled process, especially for novices of the discipline. Therefore, tools supporting the literature-survey process may help the individual scientist to explore new useful domains. Natural language processing (NLP is expected as one of the promising techniques to retrieve, abstract, and extract knowledge. In this contribution, NLP is firstly applied to the literature of chemical vapor deposition (CVD, which is a sub-discipline of materials science and is a complex and interdisciplinary field of research involving chemists, physicists, engineers, and materials scientists. Causal knowledge extraction from the literature is demonstrated using NLP.

  3. Resilience of the natural phyllosphere microbiota of the grapevine to chemical and biological pesticides.

    Science.gov (United States)

    Perazzolli, Michele; Antonielli, Livio; Storari, Michelangelo; Puopolo, Gerardo; Pancher, Michael; Giovannini, Oscar; Pindo, Massimo; Pertot, Ilaria

    2014-06-01

    The phyllosphere is colonized by complex microbial communities, which are adapted to the harsh habitat. Although the role and ecology of nonpathogenic microorganisms of the phyllosphere are only partially understood, leaf microbiota could have a beneficial role in plant growth and health. Pesticides and biocontrol agents are frequently applied to grapevines, but the impact on nontarget microorganisms of the phyllosphere has been marginally considered. In this study, we investigated the effect of a chemical fungicide (penconazole) and a biological control agent (Lysobacter capsici AZ78) on the leaf microbiota of the grapevine at three locations. Amplicons of the 16S rRNA gene and of the internal transcribed spacer were sequenced for bacterial and fungal identification, respectively. Pyrosequencing analysis revealed that the richness and diversity of bacterial and fungal populations were only minimally affected by the chemical and biological treatments tested, and they mainly differed according to grapevine locations. Indigenous microbial communities of the phyllosphere are adapted to environmental and biotic factors in the areas where the grapevines are grown, and they are resilient to the treatments tested. The biocontrol properties of phyllosphere communities against downy mildew differed among grapevine locations and were not affected by treatments, suggesting that biocontrol communities could be improved with agronomic practices to enrich beneficial populations in vineyards.

  4. Chemical nature of alkaline polyphosphate boundary film at heated rubbing surfaces

    Science.gov (United States)

    Wan, Shanhong; Tieu, A. Kiet; Zhu, Qiang; Zhu, Hongtao; Cui, Shaogang; Mitchell, David R. G.; Kong, Charlie; Cowie, Bruce; Denman, John A.; Liu, Rong

    2016-05-01

    Alkaline polyphosphate has been demonstrated to be able to reduce significant wear and friction of sliding interfaces under heavy loads (>1 GPa) and elevated temperature (800 °C and above) conditions, e.g. hot metal manufacturing. The chemical composition and fine structure of polyphosphate lubricating film is not well understood as well as the role of alkaline elements within the reaction film at hot rubbing surface. This work makes use of the coupling surface analytical techniques on the alkaline polyphosphate tribofilm, XANES, TOF-SIMS and FIB/TEM. The data show the composition in gradient distribution and trilaminar structure of tribofilm: a shorter chain phosphate overlying a long chain polyphosphate that adheres onto oxide steel base through a short chain phosphate. The chemical hardness model well explains the anti-abrasive mechanism of alkaline polyphosphate at elevated temperatures and also predicts a depolymerisation and simultaneous cross-linking of the polyphosphate glass. The role of alkaline elements in the lubrication mechanism is especially explained. This work firstly serves as a basis for a detailed study of alkaline polyphosphate tribofilm at temperature over 600 °C.

  5. The nature of chemical bond in trioxide Mi-UO3

    Directory of Open Access Journals (Sweden)

    Teterin Yury A.

    2002-01-01

    Full Text Available Low-energy X-ray photoelectron and conversion electron spectra from uranium trioxide were measured, and calculations were done for the [UO2O4]-6 (D4b cluster which reflects the structure of uranium close environment in MI-UO3 in the non-relativistic and relativistic Xa-DVM approximation. This enabled a satisfactory qualitative and in some cases quantitative agreement between the experimental and theoretical data, and interpretation of such spectra. Despite the traditional opinion that before participation in the chemical binding, the U5f electrons could be promoted to the higher (for example - U6d levels, it was theoretically proved and experimentally confirmed that the U5f electrons (about two U5f electrons are able to participate directly in the chemical bond formation in uranium trioxide. The filled U5f states proved to be localized in the outer valence molecular orbitals energy range 4-9 eV, while the vacant U5f states were generally localized in the low-energy range (0-6 eV above zero. It was experimentally shown that U6p electrons not only participate effectively in the inner valence molecular orbital formation but also participate strongly (more than 1 U6p electron in the formation of die filled outer valence molecular orbitals.

  6. In vitro activity of natural and chemical products on sporulation of Eimeria species oocysts of chickens.

    Science.gov (United States)

    Gadelhaq, Sahar M; Arafa, Waleed M; Abolhadid, Shawky M

    2018-02-15

    This study was designed to investigate the ability of two herbal extracts and different chemical substances to inhibit or disrupt sporulation of Eimeria species oocysts of the chickens. The two herbal extracts were Allium sativum (garlic) and Moringa olifiera while the chemical substances included commercial disinfectants and diclazuril. Field isolates of Eimeria oocysts were propagated in chickens to obtain a continuous source of oocysts. The collected unsporulated oocysts (10 5 oocysts/5 ml) were dispensed into 5 cm Petri dish. Three replicates were used for each treatment. The treated oocysts were incubated for 48 h at 25-29 °C and 80% relative humidity. The results showed that herbal extracts, the commercial recommended dose of Dettol, TH4, Phenol, Virkon ® S, and Diclazuril 20% have no effect on the sporulation. While Sodium hypochlorite showed a significant degree of sporulation inhibition reached to 49.67%. Moreover, 70% ethanol, and 10% formalin showed 100% sporulation inhibition. It was concluded that 70% ethanol and 10% formalin are the most effective methods to inhibit Eimeria species sporulation. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Natural Gas Residual Fluids: Sources, Endpoints, and Organic Chemical Composition after Centralized Waste Treatment in Pennsylvania.

    Science.gov (United States)

    Getzinger, Gordon J; O'Connor, Megan P; Hoelzer, Kathrin; Drollette, Brian D; Karatum, Osman; Deshusses, Marc A; Ferguson, P Lee; Elsner, Martin; Plata, Desiree L

    2015-07-21

    Volumes of natural gas extraction-derived wastewaters have increased sharply over the past decade, but the ultimate fate of those waste streams is poorly characterized. Here, we sought to (a) quantify natural gas residual fluid sources and endpoints to bound the scope of potential waste stream impacts and (b) describe the organic pollutants discharged to surface waters following treatment, a route of likely ecological exposure. Our findings indicate that centralized waste treatment facilities (CWTF) received 9.5% (8.5 × 10(8) L) of natural gas residual fluids in 2013, with some facilities discharging all effluent to surface waters. In dry months, discharged water volumes were on the order of the receiving body flows for some plants, indicating that surface waters can become waste-dominated in summer. As disclosed organic compounds used in high volume hydraulic fracturing (HVHF) vary greatly in physicochemical properties, we deployed a suite of analytical techniques to characterize CWTF effluents, covering 90.5% of disclosed compounds. Results revealed that, of nearly 1000 disclosed organic compounds used in HVHF, only petroleum distillates and alcohol polyethoxylates were present. Few analytes targeted by regulatory agencies (e.g., benzene or toluene) were observed, highlighting the need for expanded and improved monitoring efforts at CWTFs.

  8. The influence of natural factors on the concentrations of chemical elements in urban soils

    Science.gov (United States)

    Alekseenko, Alexey; Alekseenko, Vladimir

    2013-04-01

    The statistically treated results of more than 10 000 soil samples analyses for 25 elements were used during the work preparing. For estimating the total influence of natural factors on the global level we could consider the average concentrations in urban soils (the Clarke numbers of urban soils) with the average concentrations in the Earth crust and Earth soils. The analysis showed the heredity of general properties of elements concentrations from the Earth crust. However the higher concentrations of As, Cd, Cs, Mo, N, S, Ti and V in the soils of cities are explained by the combined effects of processes of soil formation and human impact, and Zn, Pb, Ba, Sr, Ca, Hg, B - by the prevailing human impact. On the regional level the natural factors influence was estimated by the comparing of soils of cities with the equal technogenic impact and number of population, but located in different geographical and climate zones. The common conformities with law were not found out, but the mentioned factors had an effect on the elements concentrations. The valuation of natural factors influence in the soils of one city was carried out by comparison the urban landscapes soils, which differ only in one characteristic. Geomorphologic peculiarities had the doubtless influence on the background concentrations of Pb, Sr, Ag, Zn, Yb, Co, Sn, Cr. etc., but in every case the connection of maximum and minimum background concentrations of the specific elements with the certain geomorphologic structures depended on number of building storeys, location of industrial zones, parks, etc. The certain associations of plants were also affected the background elements concentrations in soils of several cities. The increased concentrations of elements were more often detected - other things being equal - in the landscapes with mixed decorative fruit and berry plant association (?u, Pb, Co, Mn, Ti, Sr), less often - with agricultural fruit and berry plant association (Zn, Ag, Sn, Ba, Cr). In parks

  9. Immobilizing of catalyst using Bayah's natural zeolite to reduce the chemical oxygen demand (COD) and total organic carbon (TOC)

    Science.gov (United States)

    Jayanudin, Kustiningsih, Indar; Sari, Denni Kartika

    2017-05-01

    Indonesia is rich of natural minerals, many of which had not been widely used. One potential natural mineral is zeolite from Bayah Banten that can be used to support catalyst in the process of waste degradation. The purpose of this research is to characterize the Bayah's zeolite and to figure out the effectiveness of the zeolite as supporting agent to the Fe catalyst in the process of phenol degradation, with the main purposes are to reduce the Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC). This research consists of three steps, activation of natural zeolite using 1M, 2M, and 3M NaOH solution, impregnation process with 0.025M, 0.05 M and 0.075M Fe(NO3)3.9H2O solution, and calcination at 500°C. Bayah's natural zeolite was characterize using Brauner-Emmet-Teller (BET) for its pore area, X-ray Fluorescence (XRF) for analyzing zeolite's component before and after activation process and after impregnation process, and Scanning Electron Microscope (SEM) for analyzing zeolite's morphology. The result showed that the highest pore area was 9Å, Fe metal from Fe(NO3)3.9H2O 0,075 M solution remained in zeolite pore was 7,73%, the reduction of COD and TOC was yielded at H2O2: phenol ratio of 1 : 6.

  10. Effects of chemical elements in the trophic levels of natural salt marshes.

    Science.gov (United States)

    Kamiński, Piotr; Barczak, Tadeusz; Bennewicz, Janina; Jerzak, Leszek; Bogdzińska, Maria; Aleksandrowicz, Oleg; Koim-Puchowska, Beata; Szady-Grad, Małgorzata; Klawe, Jacek J; Woźniak, Alina

    2016-06-01

    The relationships between the bioaccumulation of Na, K, Ca, Mg, Fe, Zn, Cu, Mn, Co, Cd, and Pb, acidity (pH), salinity (Ec), and organic matter content within trophic levels (water-soil-plants-invertebrates) were studied in saline environments in Poland. Environments included sodium manufactures, wastes utilization areas, dumping grounds, and agriculture cultivation, where disturbed Ca, Mg, and Fe exist and the impact of Cd and Pb is high. We found Zn, Cu, Mn, Co, and Cd accumulation in the leaves of plants and in invertebrates. Our aim was to determine the selectivity exhibited by soil for nutrients and heavy metals and to estimate whether it is important in elucidating how these metals are available for plant/animal uptake in addition to their mobility and stability within soils. We examined four ecological plant groups: trees, shrubs, minor green plants, and water macrophytes. Among invertebrates, we sampled breastplates Malacostraca, small arachnids Arachnida, diplopods Diplopoda, small insects Insecta, and snails Gastropoda. A higher level of chemical elements was found in saline polluted areas (sodium manufactures and anthropogenic sites). Soil acidity and salinity determined the bioaccumulation of free radicals in the trophic levels measured. A pH decrease caused Zn and Cd to increase in sodium manufactures and an increase in Ca, Zn, Cu, Cd, and Pb in the anthropogenic sites. pH increase also caused Na, Mg, and Fe to increase in sodium manufactures and an increase in Na, Fe, Mn, and Co in the anthropogenic sites. There was a significant correlation between these chemical elements and Ec in soils. We found significant relationships between pH and Ec, which were positive in saline areas of sodium manufactures and negative in the anthropogenic and control sites. These dependencies testify that the measurement of the selectivity of cations and their fluctuation in soils provide essential information on the affinity and binding strength in these environments. The

  11. The Chemical Nature of Mercury in Human Brain Following Poisoning or Environmental Exposure

    Science.gov (United States)

    2010-01-01

    Methylmercury is among the most potentially toxic species to which human populations are exposed, both at high levels through poisonings and at lower levels through consumption of fish and other seafood. However, the molecular mechanisms of methylmercury toxicity in humans remain poorly understood. We used synchrotron X-ray absorption spectroscopy (XAS) to study mercury chemical forms in human brain tissue. Individuals poisoned with high levels of methylmercury species showed elevated cortical selenium with significant proportions of nanoparticulate mercuric selenide plus some inorganic mercury and methylmercury bound to organic sulfur. Individuals with a lifetime of high fish consumption showed much lower levels of mercuric selenide and methylmercury cysteineate. Mercury exposure did not perturb organic selenium levels. These results elucidate a key detoxification pathway in the central nervous system and provide new insights into the appropriate methods for biological monitoring. PMID:22826746

  12. Chemical Components and Pharmacological Activities of Terpene Natural Products from the Genus Paeonia.

    Science.gov (United States)

    Zhao, Dan-Dan; Jiang, Li-Li; Li, Hong-Yi; Yan, Peng-Fei; Zhang, Yan-Long

    2016-10-13

    Paeonia is the single genus of ca. 33 known species in the family Paeoniaceae, found in Asia, Europe and Western North America. Up to now, more than 180 compounds have been isolated from nine species of the genus Paeonia, including terpenes, phenols, flavonoids, essential oil and tannins. Terpenes, the most abundant naturally occurring compounds, which accounted for about 57% and occurred in almost every species, are responsible for the observed in vivo and in vitro biological activities. This paper aims to give a comprehensive overview of the recent phytochemical and pharmacological knowledge of the terpenes from Paeonia plants, and enlighten further drug discovery research.

  13. Chemical Components and Pharmacological Activities of Terpene Natural Products from the Genus Paeonia

    Directory of Open Access Journals (Sweden)

    Dan-Dan Zhao

    2016-10-01

    Full Text Available Paeonia is the single genus of ca. 33 known species in the family Paeoniaceae, found in Asia, Europe and Western North America. Up to now, more than 180 compounds have been isolated from nine species of the genus Paeonia, including terpenes, phenols, flavonoids, essential oil and tannins. Terpenes, the most abundant naturally occurring compounds, which accounted for about 57% and occurred in almost every species, are responsible for the observed in vivo and in vitro biological activities. This paper aims to give a comprehensive overview of the recent phytochemical and pharmacological knowledge of the terpenes from Paeonia plants, and enlighten further drug discovery research.

  14. Evaluation of some microbial agents, natural and chemical compounds for controlling tomato leaf miner, Tuta absoluta (Meyrick (Lepidoptera: Gelechiidae

    Directory of Open Access Journals (Sweden)

    Abd El-Ghany Nesreen M.

    2016-12-01

    Full Text Available Solanaceous plants have a great economic impact in Egypt. These groups of plants include potatoes, tomatoes and eggplants. The new invasive pest of tomatoes, Tuta absoluta (Meyrick causes the greatest crop losses which can range from 60 to 100%. After its detection in Egypt during the last half of 2009, it spread quickly to all provinces in the country. We aiming to propose a sustainable control program for this devastating pest. In this research we tested three groups of control agents. The first was microbial and natural, the second - plant extracts and the third - chemical insecticides. Our results showed that the impact of T. absoluta can be greatly reduced by the use of sustainable control measures represented by different insecticide groups. Bioassay experiments showed that this devastating pest can be controlled with some compounds that give high mortality rates. Of these compounds, spinosad and Beauveria bassiana, microbial control agents, followed by azadirachtin, gave the best results in controlling T. absoluta. Of the chemical insecticides, lambda-cyhalotrin was the most effective, followed by lufenuron and profenofos. In conclusion we encourage farmers to use microbial and natural control measures in combating the tomato leafminer, T. absoluta, in Integrated Pest Mangement (IPM programs.

  15. Thermodynamics and sorption characteristics of Zn(II) onto natural and chemically modified zeolites for agricultural and environmental using

    Science.gov (United States)

    Saltali, K.; Tazebay, N.; Kaya, M.

    2017-10-01

    Zeolites with high porous and cation exchange capacity have been widely used for agricultural and environmental purposes. This study was conducted to assess the thermodynamics and sorption characteristics of chemically modified zeolite (CMZ) from obtained natural zeolite (NZ), and to compare its properties. At first step of the sorption experiment, effects of pH, slurry concentration, stirring time, and heat on Zn removal were determined. Linear Langmuir isotherm was well fitted to data, and maximum sorption capacities ( q max) were calculated as 20.87 and 33.44 mg/g for NZ and CMZ, respectively. Dubinin-Redushkevich (D-R) isotherm showed that the adsorption process was probably controlled by chemical ion-exchange mechanism. The solubility of zinc DTPA should be so directly related to the model of D-R model. Therefore, zeolites can be used as carrier Zn in soils with insufficient zinc arid and semiarid regions. Enthalpy (Δ H°) and entropy (Δ S°) values were positive. The change values of Gibbs free energy (Δ G°) illustrated that the sorption of Zn ions onto zeolites was feasible and spontaneous. From the obtained results, it could be concluded that chemical modification increased q max value of NZ, and the findings indicate clearly the possibility of using NZ and CMZ as Zn carrier in agricultural and also environmental treatments.

  16. Investigation of chemical modifiers for the determination of lead in fertilizers and limestone using graphite furnace atomic absorption spectrometry with Zeeman-effect background correction and slurry sampling

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Aline R. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq–INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Becker, Emilene M.; Dessuy, Morgana B. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Vale, Maria Goreti R., E-mail: mgrvale@ufrgs.br [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 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); Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil)

    2014-02-01

    In this work, chemical modifiers in solution (Pd/Mg, NH{sub 4}H{sub 2}PO{sub 4} and NH{sub 4}NO{sub 3}/Pd) were compared with permanent modifiers (Ir and Ru) for the determination of lead in fertilizer and limestone samples using slurry sampling and graphite furnace atomic absorption spectrometry with Zeeman-effect background correction. The analytical line at 283.3 nm was used due to some spectral interference observed at 217.0 nm. The NH{sub 4}H{sub 2}PO{sub 4} was abandoned due to severe spectral interference even at the 283.3-nm line. For Pd/Mg and NH{sub 4}NO{sub 3}/Pd the optimum pyrolysis and atomization temperatures were 900 °C and 1900 °C, respectively. For Ru and Ir, the integrated absorbance signal was stable up to pyrolysis temperatures of 700 °C and 900 °C, respectively, and up to atomization temperature of 1700 °C. The limit of detection (LOD) was 17 ng g{sup −1} using Pd/Mg and 29 ng g{sup −1} using NH{sub 4}NO{sub 3}/Pd. Among the permanent modifiers investigated, the LOD was 22 ng g{sup −1} Pb for Ir and 10 ng g{sup −1} Pb for Ru. The accuracy of the method was evaluated using the certified reference material NIST SRM 695. Although Ru provided lower LOD, which can be attributed to a lower blank signal, only the modifiers in solution showed concordant values of Pb concentration for the NIST SRM 695 and the most of analyzed samples. Moreover, the Pd/Mg modifier provided the highest sensitivity and for this reason it is more suitable for the determination of Pb in fertilizers samples in slurry; besides this it presented a better signal-to-noise ratio than NH{sub 4}NO{sub 3}/Pd. - Highlights: • Lead has been determined in fertilizers using slurry sampling GF AAS. • The mixture of palladium and magnesium nitrates was found to be the ideal chemical modifier. • Calibration could be carried out against aqueous standard solutions. • The proposed method is much faster than the EPA method, which includes sample digestion.

  17. Evaluation of soluble corn fiber on chemical composition and nitrogen-corrected true metabolizable energy and its effects on in vitro fermentation and in vivo responses in dogs.

    Science.gov (United States)

    Panasevich, M R; Kerr, K R; Serao, M C Rossoni; de Godoy, M R C; Guérin-Deremaux, L; Lynch, G L; Wils, D; Dowd, S E; Fahey, G C; Swanson, K S; Dilger, R N

    2015-05-01

    Dietary fermentable fiber is known to benefit intestinal health of companion animals. Soluble corn fiber (SCF) was evaluated for its chemical composition, nitrogen-corrected true ME (TMEn) content, in vitro digestion and fermentation characteristics, and in vivo effects on nutrient digestibility, fecal fermentation end products, and modulation of the fecal microbiome of dogs. Soluble corn fiber contained 78% total dietary fiber, all present as soluble dietary fiber; 56% was low molecular weight soluble fiber (did not precipitate in 95% ethanol). The SCF also contained 26% starch and 8% resistant starch and had a TMEn value of 2.6 kcal/g. Soluble corn fiber was first subjected to in vitro hydrolytic-enzymatic digestion to determine extent of digestibility and then fermented using dog fecal inoculum, with fermentative outcomes measured at 0, 3, 6, 9, and 12 h. Hydrolytic-enzymatic digestion of SCF was only 7%. In vitro fermentation showed increased (P Fermentability of SCF was higher (P fermentation end products and permit a microbiome analysis. For microbiome analysis, extraction of DNA was followed by amplification of the V4 to V6 variable region of the 16S rRNA gene using barcoded primers. Sequences were classified into taxonomic levels using a nucleotide basic local alignment search tool (BLASTn) against a curated GreenGenes database. Few changes in nutrient digestibility or fecal fermentation end products or stool consistency were observed, and no appreciable modulation of the fecal microbiome occurred. In conclusion, SCF was fermentable in vitro, but higher dietary concentrations may be necessary to elicit potential in vivo responses.

  18. IMPROVING POSTHARVEST VASE-LIFE AND QUALITY OF CUT GERBERA FLOWERS USING NATURAL AND CHEMICAL PRESERVATIVES

    Directory of Open Access Journals (Sweden)

    Mehrdad Jafarpour

    2015-06-01

    Full Text Available Gerbera is one of ten popular cut flowers in the world which occupies the forth place according to the global trends in floriculture. Hence, this study aimed to investigate the effects of chemical, hormonal and essential oil substances in preservative solutions to improve its postharvest qualitative characteristics. Two pulse treatments including distilled water (pulse1 and 4% CaCl2 + 3% sucrose (pulse2 for 24 hour were applied before long-time treatments. Long-time treatments were comprised of (1 Hormonal treatments: 0, 25, 30 mg*l-1 Gibberellic acid, 0, 150, 250 mg*l-1 Benzyl adenine and 0, 100, 200 mg*l-1 5-Sulfosalicylic acid (2 Chemical treatments: 0, 0.4, 0.8 mM Silver thiosulphate, 0, 5, 10 mg*l-1 Nano-silver particles, 0, 4, 6 mM Aminooxy acetic acid and 0, 200 and 400 mg*l-1 8-hydroxyquinoline sulphate (3 Essential oils: Thymus essential oil and Stevia essential oils (0, 0.1 and 0.2 mg*l-1. Data were subjected to analysis of variance based on the factorial experiment model in the layout completely randomized design. Mean comparison was performed using the Duncan’s multiple range test. Parameters of fresh weight, stem bending, capitulum diameter, carotenoid pigments of petal and vase-life longevity were evaluated during 12 days. The highest fresh weight was obtained when cut flowers were held in a solution containing pulse1 + 250 mg*l-1 BA. Among all treatments, 8-HQS treatment showed the best effects on preventing stem bending, increasing capitulum diameter and also on prolonging of vase-life, but nonetheless, the effects of pulse treatments and 8-HQS concentrations were insignificant. To conclude, 200 mg*l-1 8-HQS without pulse treatment has the potential to be used as a commercial preservative solution to improve the keeping quality and vase-life of this important cut flower.

  19. Experimental and quantum chemical studies on poriferasterol - A natural phytosterol isolated from Cassia sophera Linn. (Caesalpiniaceae)

    Science.gov (United States)

    Brahmachari, Goutam; Mondal, Avijit; Nayek, Nayana; Kumar, Abhishek; Srivastava, Ambrish Kumar; Misra, Neeraj

    2017-09-01

    Poriferasterol, a biologically relevant phytosterol, has been isolated and identified first-time from Cassia sophera Linn. (family: Caesalpiniaceae) based on detailed spectral studies. Exhaustive theoretical studies on the molecular structure, vibrational spectra, HOMO, LUMO, MESP surfaces and reactivity descriptor of this plant-derived natural molecule have been performed. The experimentally observed FT-IR spectrum of the title compound has been compared with spectral data obtained by DFT-B3LYP/6-311 + G (d,p) method. The UV-visible spectrum of the title compound has also been recorded and the electronic properties, such as frontier orbitals and band gap energy are measured by TD-DFT approach. The 1H and 13C NMR spectrum has been calculated by using the gauge independent atomic orbital method and compared with the observed data.

  20. Chemical and isotopic composition of natural waters in the Jizuki-yama landslide area, Nagano Prefecture

    Energy Technology Data Exchange (ETDEWEB)

    Yoshioka, Ryuma; Mashima, Kiyotaka; Koizumi, Naoji

    1988-10-01

    A large-scale landslide took place at a southeastern slope of Mt. Jizuki, Nagano Prefecture, on July 26, 1985. It has been said that landslide is closely related to the hydrological and hydrogeochemical nature of groundwater involved. To investigate the weathering mechanism and the origin of groundwater, we collected and analyzed water samples from the large-scale landslide area. The following facts can be pointed out: (1) weather-rock interaction is remarkably active in the landslide area, (2) most of the waters from the landslide area are in equilibrium with Na-montmorillonite (3) immediately after the landslide occurred bicarbonate and sodium ions are dominant, but sulfate and sodium ions become dominant with time, and (4) groundwater passing through horizontally drilled holes dose not effectively drain off to stabilize a slope in the landslide area. And our hypothesis on the mechanism for the formation of sodium sulfate type water is also presented.

  1. Chemical composition of natural colophony from Pinus brutia and comparison with synthetic colophony.

    Science.gov (United States)

    Gören, Ahmet C; Bilsel, Gökhan; Oztürk, Alp Hakan; Topçu, Gülaçti

    2010-11-01

    The compositions of colophony resins obtained from Pinus brutia Ten trees by three different methods (acid paste, carved hole and scraping) from Ayvacik, Gökova and Kemalpaşa in Turkey were analyzed by capillary GC-MS. The main components were the monoterpenes alpha-pinene, beta-pinene, and delta3-carene, and the diterpenic resin acids palustric, abietic, kaur-9(11)-16-en-18-oic and neoabietic acid. The synthetic colophony resins exhibited similar contents to those of the natural resins obtained from the Gökova and Kemalpaşa regions of Turkey. However, colophony resins from Ayvacik exhibited only half the diterpenic acid content as those of the Gökova and Kemalpaşa resins. Out of the three techniques, the carved hole method caused rather different percentages in the constituents of the essential oils.

  2. The nature of resonance-assisted hydrogen bonds: a quantum chemical topology perspective.

    Science.gov (United States)

    Guevara-Vela, José Manuel; Romero-Montalvo, Eduardo; Costales, Aurora; Pendás, Ángel Martín; Rocha-Rinza, Tomás

    2016-10-14

    Resonance Assisted Hydrogen Bonds (RAHBs) are particularly strong H-Bonds (HBs) which are relevant in several fields of chemistry. The traditional explanation for the occurrence of these HBs is built on mesomeric structures evocative of electron delocalisation in the system. Nonetheless, there are several theoretical studies which have found no evidence of such electron delocalisation. We considered the origin of RAHBs by employing Quantum Chemical Topology tools, more specifically, the Quantum Theory of Atoms in Molecules (QTAIM) and the Interacting Quantum Atoms energy partition. Our results indicate that the π-conjugated bonds allow for a larger adjustment of electron density throughout the H-bonded system as compared with non-conjugated carbonyl molecules. This rearrangement of charge distribution is a response to the electric field due to the H atom involved in the hydrogen bonding of the considered compounds. As opposed to the usual description of RAHB interactions, these HBs lead to a larger electron localisation in the system, and concomitantly to larger QTAIM charges which in turn lead to stronger electrostatic, polarization and charge transfer components of the interaction. Overall, the results presented here offer a new perspective on the cause of strengthening of these important interactions.

  3. Hydraulic Behavior and Chemical Characterization of Lapilli as Material for Natural Filtering of Slurry

    Directory of Open Access Journals (Sweden)

    Nereida Falcón-Cardona

    2015-06-01

    Full Text Available Livestock effluents are a beneficial nutrient supply for crops, whereby their use is critical to ensure the sustainability of the farms global management. However, they can cause serious ecological problems if misused, polluting soils and groundwater. Combining “soft technology” and local materials is a low cost solution in terms of finance and energy. The REAGUA project (REuso AGUA, Water reuse in Spanish analyzes the possibility of using “picon” (lapilli as a material for the treatment of liquid manure from ruminants, for later use in subsurface drip irrigation system to produce forage and biofuels, in which the soil acts as a subsequent advanced treatment. A three-phase system, in which the effluent was poured with a vertical subsurface flow in an unsaturated medium, is designed. In order to determine the management conditions that optimize the filter, it was necessary to characterize the hydraulic behavior of lapilli and its ability to remove substances. Using three lapilli-filled columns, unsaturated flux, and a ruminant effluent, the reduction of chemical oxygen demand (COD, biochemical oxygen demand after 5 days (BOD5 and ammonia, phosphorus and suspension solids (SS obtained was over 80%, 90%, and 95% respectively, assumable values for irrigation.

  4. Surface chemical effects on colloid stability and transport through natural porous media

    Science.gov (United States)

    Puls, Robert W.; Paul, Cynthia J.; Clark, Donald A.

    1993-01-01

    Surface chemical effects on colloidal stability and transport through porous media were investigated using laboratory column techniques. Approximately 100 nm diameter, spherical, iron oxide particles were synthesized as the mobile colloidal phase. The column packing material was retrieved from a sand and gravel aquifer on Cape Cod, MA. Previous studies have indicated enhanced stability and transport of iron oxide particles due to specific adsorption of some inorganic anions on the iron oxide surface. This phenomenon was further evaluated with an anionic surfactant, sodium dodecyl sulfate. Surfactants constitute a significant mass of the contaminant loading at the Cape Cod site and their presence may contribute to colloidal transport as a significant transport mechanism at the site. Other studies at the site have previously demonstrated the occurrence of this transport mechanism for iron phosphate particles. Photon correlation spectroscopy, micro-electrophoretic mobility, and scanning electron microscopy were used to evaluate particle stability, mobility and size. Adsorption of negatively charged organic and inorganic species onto the surface of the iron oxide particles was shown to significantly enhance particle stability and transport through alterations of the electrokinetic properties of the particle surface. Particle breakthrough generally occurred simultaneously with tritiated water, a conservative tracer. The extent of particle breakthrough was primarily dependent upon colloidal stability and surface charge.

  5. Chemical Polymorphism of Origanum compactum Grown in All Natural Habitats in Morocco.

    Science.gov (United States)

    Aboukhalid, Kaoutar; Lamiri, Abdeslam; Agacka-Mołdoch, Monika; Doroszewska, Teresa; Douaik, Ahmed; Bakha, Mohamed; Casanova, Joseph; Tomi, Félix; Machon, Nathalie; Faiz, Chaouki Al

    2016-09-01

    Origanum compactum L. (Lamiaceae) is one of the most important medicinal species in term of ethnobotany in Morocco. It is considered as a very threatened species as it is heavily exploited. Its domestication remains the most efficient way to safeguard it for future generations. For this purpose, wide evaluation of the existing variability in all over the Moroccan territory is required. The essential oils of 527 individual plants belonging to 88 populations collected from the whole distribution area of the species in Morocco were analyzed by GC/MS. The dominant constituents were carvacrol (0 - 96.3%), thymol (0 - 80.7%), p-cymene (0.2 - 58.6%), γ-terpinene (0 - 35.2%), carvacryl methyl ether (0 - 36.2%), and α-terpineol (0 - 25.8%). While in the Middle Atlas region and the Central Morocco mainly carvacrol type samples were found, much higher chemotypic diversity was encountered within samples from the north part of Morocco (occidental and central Rif regions). The high chemical polymorphism of plants offers a wide range for selection of valuable chemotypes, as a part of breeding and domestication programs of this threatened species. © 2016 Wiley-VHCA AG, Zürich.

  6. Chemical and physicochemical characterization of porous hydroxyapatite ceramics made of natural bone.

    Science.gov (United States)

    Joschek, S; Nies, B; Krotz, R; Göferich, A

    2000-08-01

    The properties of a porous hydroxyapatite ceramic produced by sintering of bovine bone were investigated by using a number of physicochemical methods such as scanning electron microscopy (SEM), SEM in combination with energy dispersive X-ray spectroscopy (SEM-EDX), mercury intrusion porosimetry, krypton-adsorption, contact angle measurements, wide angle X-ray diffraction. Fourier transform infrared spectroscopy, thermal analysis, inductively coupled plasma optical atom emissions spectroscopy and flame atomic absorption spectroscopy. The results indicate that there are considerable differences between the ceramic and native bone. However, the most important properties with respect to the use of such ceramics as a biomaterial for filling bone defects namely the high porosity (> or = 57 +/- 2%) and the interconnecting pore system are maintained. While macropores with an average diameter of approx. 300 microm contribute 97% to porosity, micropores with an average diameter of 1.3 microm account for only 3% of the total porosity. The surface area was found to be approx. 0.1 m2/g. The contact angles of water (44.6 +/- 15.4 degrees, n = 5) and tetrahydrofurane (10 degrees) allow the processing of the ceramic to a drug carrier by incubation with aqueous or organic drug solutions. The ceramic is highly crystalline with crystal sizes of 1-7 microm and contains crystal bridges. The investigation of its chemical composition revealed small amounts of other inorganic compounds such as Ca4O(PO4)2, NaCaPO4, Ca3(PO4)2, CaO, and MgO. Besides trace amounts of aluminum, iron, magnesium, potassium, silica, sodium, vanadium and zinc it contains probably carbonated apatite.

  7. The online assignment of the absolute configuration of natural products: HPLC-CD in combination with quantum chemical CD calculations.

    Science.gov (United States)

    Bringmann, Gerhard; Gulder, Tobias A M; Reichert, Matthias; Gulder, Tanja

    2008-05-15

    The application of modern online methods, e.g., HPLC-MS/MS and HPLC-NMR, allows the elucidation of constitutions and relative configurations of new natural products directly from crude extracts. To additionally establish the full absolute configurations of such secondary metabolites without the necessity of first isolating the compounds, we have introduced HPLC-CD coupling (CD = circular dichroism) into natural product analysis, taking advantage of the different chiroptical properties of stereoisomers, in particular of enantiomers. In combination with quantum chemical CD calculations this method allows the stereochemical characterization of (even structurally unprecedented) chiral molecules, thus avoiding the--often risky--merely empirical assignment by comparison with the CD spectra of related compounds with known absolute stereostructures, or by other methods such as, e.g., the exciton chirality approach. This review presents the experimental requirements for the hyphenation and the theoretical background of the calculation of UV and CD spectra, which is then exemplified by some recent HPLC-CD applications to the elucidation of absolute configurations of most diverse compounds of mainly natural origin. Copyright 2007 Wiley-Liss, Inc.

  8. Ultrafiltration separation of aquatic natural organic matter: chemical probes for quality assurance.

    Science.gov (United States)

    Revchuk, Alex D; Suffet, I H Mel

    2009-08-01

    Characterization of molecular size of natural organic matter (NOM) is a valuable tool when assessing its effect on the performance of water treatment systems as well as its geochemical origin. Size fractionation can be accomplished by ultrafiltration (UF). Unfortunately, membrane manufacturing generates a range of pore sizes. Many membrane manufacturers use molecular weight cutoff (MWCO) metric based on a 90% retention of given solute after specified duration of filtration. The objective of this study was to characterize the ability of different commercially available UF membranes to separate different size fractions of NOM. The UF membranes characterized were YM (regenerated cellulose, negatively charged) and PB (polyethersulfone, negatively charged) product lines by Millipore. The probes used to represent the size, shape and charge of NOM were polymers (polyethylene glycols (PEGs), dextrans, polystyrene sulfonates (PSSs)), dyes (bromocresol green, congo red, methyl red, methyl orange) and biological molecules (vitamin B-12 and bacitracin). The results show that MWCO definition does not hold for membranes of 5kDa and 10kDa pore openings using most polymers and dyes. The MWCO definition holds for 1kDa membrane for all tested probes. Under natural water conditions PSSs assume random coil configurations that are nearly identical to Suwannee fulvic acid. The results show that PSS agrees with stated MWCOs. The study demonstrates that ultrafiltration is not a simple mechanical sieving process, but that charges on the membrane and the constituent play a significant role in the rejection process. Effective probe size was increased seven- to fourteen-fold by charge interactions between the negative probes and negatively charged membrane. Uncharged molecules larger than specified MWCOs are able to pass through pores (PEGs), while small charged molecules (dyes) do not pass. For probes with low or neutral charges, shape becomes an important factor, with globular being favored

  9. A naturally occurring diatom frustule as a SERS substrate for the detection and quantification of chemicals

    Science.gov (United States)

    Chamuah, Nabadweep; Chetia, Lakhi; Zahan, Nashrat; Dutta, Sibasish; Ahmed, Gazi A.; Nath, Pabitra

    2017-05-01

    Naturally occurring photonic crystal structures play an important role in different fields of application. Herein, we exploit the periodic pore pattern of a diatom frustule and demonstrate surface-enhanced Raman scattering (SERS) using its structure as a template for the SERS substrate. Gold nanoparticles (AuNPs) were initially allowed to self-assemble on the surface and inside the pores of the diatoms. The enhancement in the localized surface plasmon resonance (LSPR) field magnitude for the assembled AuNPs on the diatom frustule were studied using simulation software. For the proposed SERS substrate, an average field enhancement of the order of 108 magnitude was observed. We demonstrate the operation of the designed substrate for the detection and quantification of Raman signals from two Raman active samples, namely malachite green (MG) and fluoride concentrations in drinking water. Using the proposed SERS substrate, an MG concentration as low as 1 nM with a relative standard deviation (RSD) of 7.57% and a fluoride concentration of 100 nM with an RSD of 17.26% could be measured with the Raman spectrometer. We envision that the proposed technique could emerge as an inexpensive alternative fabrication method of SERS substrates which can produce an enhanced LSPR field magnitude and scatter intense Raman signals from Raman active samples.

  10. On the nature of the reaction intermediate in the HIV-1 protease: a quantum chemical study

    Science.gov (United States)

    Carnevale, V.; Raugei, S.; Piana, S.; Carloni, P.

    2008-07-01

    Several mechanistic aspects of Aspartic Proteases' enzymatic reaction are currently highly controversial. There is general consensus that the first step of the reaction involves a nucleophilic attack of a water molecule to the substrate carbonyl carbon with subsequent formation of a metastable intermediate (INT). However, the exact nature of this intermediate is subject of debate. While ab initio and QM/MM calculations predict that INT is a neutral gem-diol specie, empirical valence bond calculations suggest that the protein frame can stabilize a charged oxyanion intermediate. Here the relative stability of the gem diol and oxyanion intermediate is calculated by performing density functional and post-Hartree-Fock calculations. The robustness of the results is assessed by increasing the size of the system and of the basis set and by performing QM/MM calculations that explicitly include protein/solvent electrostatic effects. Our results suggest that the neutral gem-diol intermediate is 20-30 kcal/mol more stable than the charged oxyanion. It is therefore concluded that only the neutral specie is populated during the enzymatic reaction.

  11. Methyl chloride via oxyhydrochlorination of methane: A building block for chemicals and fuels from natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Benson, R.L.; Brown, S.S.D.; Ferguson, S.P.; Jarvis, R.F. Jr. [Dow Corning Corp., Carrollton, KY (United States)

    1995-12-31

    The objectives of this program are to (a) develop a process for converting natural gas to methyl chloride via an oxyhydrochlorination route using highly selective, stable catalysts in a fixed-bed, (b) design a reactor capable of removing the large amount of heat generated in the process so as to control the reaction, (c) develop a recovery system capable of removing the methyl chloride from the product stream and (d) determine the economics and commercial viability of the process. The general approach has been as follows: (a) design and build a laboratory scale reactor, (b) define and synthesize suitable OHC catalysts for evaluation, (c) select first generation OHC catalyst for Process Development Unit (PDU) trials, (d) design, construct and startup PDU, (e) evaluate packed bed reactor design, (f) optimize process, in particular, product recovery operations, (g) determine economics of process, (h) complete preliminary engineering design for Phase II and (i) make scale-up decision and formulate business plan for Phase II. Conclusions regarding process development and catalyst development are presented.

  12. natural

    Directory of Open Access Journals (Sweden)

    Elías Gómez Macías

    2006-01-01

    Full Text Available Partiendo de óxido de magnesio comercial se preparó una suspensión acuosa, la cual se secó y calcinó para conferirle estabilidad térmica. El material, tanto fresco como usado, se caracterizó mediante DRX, área superficial BET y SEM-EPMA. El catalizador mostró una matriz de MgO tipo periclasa con CaO en la superficie. Las pruebas de actividad catalítica se efectuaron en lecho fijo empacado con partículas obtenidas mediante prensado, trituración y clasificación del material. El flujo de reactivos consistió en mezclas gas natural-aire por debajo del límite inferior de inflamabilidad. Para diferentes flujos y temperaturas de entrada de la mezcla reactiva, se midieron las concentraciones de CH4, CO2 y CO en los gases de combustión con un analizador de gases tipo infrarrojo no dispersivo (NDIR. Para alcanzar conversión total de metano se requirió aumentar la temperatura de entrada al lecho a medida que se incrementó el flujo de gases reaccionantes. Los resultados obtenidos permiten desarrollar un sistema de combustión catalítica de bajo costo con un material térmicamente estable, que promueva la alta eficiencia en la combustión de gas natural y elimine los problemas de estabilidad, seguridad y de impacto ambiental negativo inherentes a los procesos de combustión térmica convencional.

  13. Apoptotic role of natural isothiocyanate from broccoli (Brassica oleracea italica) in experimental chemical lung carcinogenesis.

    Science.gov (United States)

    Kalpana Deepa Priya, D; Gayathri, R; Gunassekaran, G R; Murugan, S; Sakthisekaran, D

    2013-05-01

    Sulforaphane (SFN) [1-isothiocyanato-4-(methylsulfinyl)butane] is a naturally occurring isothiocyanate found in cruciferous vegetables such as broccoli [Brassica oleracea L. var. italica Plenck. (Brassicaceae)]. Since it is among the most potent bioactive components with antioxidant and antitumor properties, it has received intense attention in the recent years for its chemopreventive properties. The present work determined the rehabilitating role in alleviating the oxidative damage caused by benzo(a)pyrene [B(a)P] to biomolecules and the apoptotic cascade mediated by orally administered isothiocyanate-SFN (9 µmol/mouse/day) against B(a)P (100 mg/kg body weight, i.p.) induced pulmonary carcinogenesis in Swiss albino mice. Oxidative damage was assessed by measuring lipid peroxidation, 8-hydroxydeoxyguanosine, hydrogen peroxide (H2O2) production, glycoprotein components, protein carbonyl levels and DNA-protein crosslinks. DNA fragmentation by agarose gel electrophoresis and caspase-3 activity by ELISA proved apoptotic induction by SFN along with the protein expression of Bcl-2, Bax and Cyt c. SFN treatment was found to decrease the H2O2 production (p < 0.001) in cancer induced animals, proving its antioxidant potential. Apoptosis was induced by increasing the release of Cyt c (p < 0.001) from mitochondria, decreasing and increasing the expression of Bcl-2 (p < 0.01) and Bax (p < 0.001), respectively. Caspase-3 activity was also enhanced (p < 0.001) which leads to DNA fragmentation in SFN treated groups. Our results reflect the rehabilitating role of SFN in B(a)P induced lung carcinogenesis.

  14. Shell structure of natural rubber particles: evidence of chemical stratification by electrokinetics and cryo-TEM.

    Science.gov (United States)

    Rochette, Christophe N; Crassous, Jérôme J; Drechsler, Markus; Gaboriaud, Fabien; Eloy, Marie; de Gaudemaris, Benoît; Duval, Jérôme F L

    2013-11-26

    The interfacial structure of natural rubber (NR) colloids is investigated by means of cryogenic transmission electron microscopy (cryo-TEM) and electrokinetics over a broad range of KNO3 electrolyte concentrations (4-300 mM) and pH values (1-8). The asymptotic plateau value reached by NR electrophoretic mobility (μ) in the thin double layer limit supports the presence of a soft (ion- and water-permeable) polyelectrolytic type of layer located at the periphery of the NR particles. This property is confirmed by the analysis of the electron density profile obtained from cryo-TEM that evidences a ∼2-4 nm thick corona surrounding the NR polyisoprene core. The dependence of μ on pH and salt concentration is further marked by a dramatic decrease of the point of zero electrophoretic mobility (PZM) from 3.6 to 0.8 with increasing electrolyte concentration in the range 4-300 mM. Using a recent theory for electrohydrodynamics of soft multilayered particles, this "anomalous" dependence of the PZM on electrolyte concentration is shown to be consistent with a radial organization of anionic and cationic groups across the peripheral NR structure. The NR electrokinetic response in the pH range 1-8 is indeed found to be equivalent to that of particles surrounded by a positively charged ∼3.5 nm thick layer (mean dissociation pK ∼ 4.2) supporting a thin and negatively charged outermost layer (0.6 nm in thickness, pK ∼ 0.7). Altogether, the strong dependence of the PZM on electrolyte concentration suggests that the electrostatic properties of the outer peripheral region of the NR shell are mediated by lipidic residues protruding from a shell containing a significant amount of protein-like charges. This proposed NR shell interfacial structure questions previously reported NR representations according to which the shell consists of either a fully mixed lipid-protein layer, or a layer of phospholipids residing exclusively beneath an outer proteic film.

  15. Effect of methionine and cysteine deprivation on growth of different natural isolates of Lactobacillus spp. in chemically defined media

    Directory of Open Access Journals (Sweden)

    Lozo Jelena

    2008-01-01

    Full Text Available The purpose of this study was to determine the ability of natural isolates of lactobacilli from different ecological niches to grow in a chemically defined medium in the presence or absence of sulphur-containing amino acids, methionine and/or cysteine. The obtained results indicate that cysteine is essential for growth of L. paracasei subsp. paracasei BGHN14 and BGSJ2-8, while methionine is essential for isolates BGHN40, BGCG31, and BGHV54T of the species L. plantarum. Methionine is also essential for growth of L. rhamnosus BGHV58T. Other analyzed strains, such as L. plantarum BGSJ3-18, BGZB19, BGHV52Ta, and BGHV43T, require the presence of both amino acids for their growth.

  16. The Fragment Molecular Orbital Method Reveals New Insight into the Chemical Nature of GPCR-Ligand Interactions.

    Science.gov (United States)

    Heifetz, Alexander; Chudyk, Ewa I; Gleave, Laura; Aldeghi, Matteo; Cherezov, Vadim; Fedorov, Dmitri G; Biggin, Philip C; Bodkin, Mike J

    2016-01-25

    Our interpretation of ligand-protein interactions is often informed by high-resolution structures, which represent the cornerstone of structure-based drug design. However, visual inspection and molecular mechanics approaches cannot explain the full complexity of molecular interactions. Quantum Mechanics approaches are often too computationally expensive, but one method, Fragment Molecular Orbital (FMO), offers an excellent compromise and has the potential to reveal key interactions that would otherwise be hard to detect. To illustrate this, we have applied the FMO method to 18 Class A GPCR-ligand crystal structures, representing different branches of the GPCR genome. Our work reveals key interactions that are often omitted from structure-based descriptions, including hydrophobic interactions, nonclassical hydrogen bonds, and the involvement of backbone atoms. This approach provides a more comprehensive picture of receptor-ligand interactions than is currently used and should prove useful for evaluation of the chemical nature of ligand binding and to support structure-based drug design.

  17. Targeting apoptosis pathways by natural compounds in cancer: marine compounds as lead structures and chemical tools for cancer therapy.

    Science.gov (United States)

    von Schwarzenberg, Karin; Vollmar, Angelika M

    2013-05-28

    Natural compounds derived from marine organisms have shown a wide variety of anti-tumor effects and a lot of attention has been drawn to further development of the isolated compounds. A vast quantity of individual chemical structures from different organisms has shown a variety of apoptosis inducing mechanisms in a variety of tumor cells. The bis-steroidal cephalostatin 1 for example, induces apoptosis via activation of caspases whereas the polyketide discodermolide inhibits cell growth by binding to and stabilizing microtubule and salisporamide A, the product of an actinobacterial strain, is an inhibitor of the proteasome. This great variety of mechanisms of action can help to overcome the multitude of resistances exhibited by different tumor specimens. Products from marine organisms and their synthetic derivates are therefore an important source for new therapeutics for single agent or combined therapy with other chemotherapeutics to support the struggle against cancer. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  18. Epilithic algae distribution along a chemical gradient in a naturally acidic river, Río Agrio (Patagonia, Argentina).

    Science.gov (United States)

    Baffico, Gustavo D

    2010-04-01

    The epilithic algae distribution along a pH gradient and the relationship between the chemical gradient and biomass development were studied in Río Agrio, a naturally acidic river located in Patagonia (Argentina). The epilithic community was monitored during the summer of three consecutive years in sites located above and below the entrance of tributaries. The epilithic community showed differences between sites based on the chemical composition of the water and the precipitates that appear on the streambed of the river. The lowest biomass, diversity, and number of species were found at the most extreme part of the river in terms of pH (ca. 2) and element concentrations. Euglena mutabilis was the dominant species in this section of the river. As pH increased (ca. 3), the community changed to be dominated by filamentous green algae (Ulothrix spp., Mougeotia sp., Klebsormidium sp.) showing luxuriant growths in terms of biomass. With the inflow of a neutral tributary, the pH of Río Agrio increased above 3, and the precipitates of orange-red iron hydroxides appeared. The algal community was not affected by these precipitates or the low P concentrations, along the next 30 km of river downstream from this site. The apparent physical stress that the precipitates impose on algae is in fact a dynamic reservoir of P because diel cycle of Fe could be promoting precipitation and redissolution processes that binds and releases P from these precipitates. Where the pH increased above 6, precipitates of aluminum hydroxides appeared. At this site, the epilithic biomass and density decreased, some algae species changed, but the diversity and the number of species in general remained consistent with the upstream values. The physical stress of the Al precipitates on the algae is added to the chemical stress that represents the sequestering of P in these precipitates that are not redissolved, resulting P a limiting nutrient for algae growth.

  19. Chemical diversity of the natural populations of Dalmatian pyrethrum (Tanacetum cinerariifolium (TREVIR.) SCH.BIP.) in Croatia.

    Science.gov (United States)

    Grdiša, Martina; Babić, Sandra; Periša, Martina; Carović-Stanko, Klaudija; Kolak, Ivan; Liber, Zlatko; Jug-Dujaković, Marija; Satovic, Zlatko

    2013-03-01

    Dalmatian pyrethrum (Tanacetum cinerariifolium (TREVIR.) SCH.BIP.) is a plant species endemic to the east Adriatic coast. The bioactive substance of Dalmatian pyrethrum is a natural insecticide, pyrethrin, a mixture of six active components (pyrethrins I and II, cinerins I and II, and jasmolins I and II). The insecticidal potential of pyrethrin was recognized decades ago, and dried and ground flowers have traditionally been used in Croatian agriculture and households. A total of 25 Dalmatian pyrethrum populations from Croatia were studied to determine the pyrethrin content and composition, and to identify distinct chemotypes. The total pyrethrin content ranged from 0.36 to 1.30% (dry flower weight; DW) and the pyrethrin I/pyrethrin II ratio ranged from 0.64 to 3.33%. The statistical analyses revealed that the correlations between the percentage of pyrethrin I and of all the other components were significant and negative. The total pyrethrin content was positively correlated with the percentage of pyrethrin I and negatively correlated with cinerin II. The multivariate analysis of the chemical variability enabled the identification of five chemotypes among 25 Dalmatian pyrethrum populations. The chemical characterization of indigenous Dalmatian pyrethrum populations may serve as a good background for future breeding and agricultural exploitation. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

  20. Accounting for natural organic matter in aqueous chemical equilibrium models: a review of the theories and applications

    Science.gov (United States)

    Dudal, Yves; Gérard, Frédéric

    2004-08-01

    Soil organic matter consists of a highly complex and diversified blend of organic molecules, ranging from low molecular weight organic acids (LMWOAs), sugars, amines, alcohols, etc., to high apparent molecular weight fulvic and humic acids. The presence of a wide range of functional groups on these molecules makes them very reactive and influential in soil chemistry, in regards to acid-base chemistry, metal complexation, precipitation and dissolution of minerals and microbial reactions. Out of these functional groups, the carboxylic and phenolic ones are the most abundant and most influential in regards to metal complexation. Therefore, chemical equilibrium models have progressively dealt with organic matter in their calculations. This paper presents a review of six chemical equilibrium models, namely N ICA-Donnan, E Q3/6, G EOCHEM, M INTEQA2, P HREEQC and W HAM, in light of the account they make of natural organic matter (NOM) with the objective of helping potential users in choosing a modelling approach. The account has taken various faces, mainly by adding specific molecules within the existing model databases (E Q3/6, G EOCHEM, and P HREEQC) or by using either a discrete (W HAM) or a continuous (N ICA-Donnan and M INTEQA2) distribution of the deprotonated carboxylic and phenolic groups. The different ways in which soil organic matter has been integrated into these models are discussed in regards to the model-experiment comparisons that were found in the literature, concerning applications to either laboratory or natural systems. Much of the attention has been focused on the two most advanced models, W HAM and N ICA-Donnan, which are able to reasonably describe most of the experimental results. Nevertheless, a better knowledge of the humic substances metal-binding properties is needed to better constrain model inputs with site-specific parameter values. This represents the main axis of research that needs to be carried out to improve the models. In addition to

  1. WDS versus silicon drift detector EDS: a case report for the comparison of quantitative chemical analyses of natural silicate minerals.

    Science.gov (United States)

    Cubukçu, H Evren; Ersoy, Orkun; Aydar, Erkan; Cakir, Uner

    2008-01-01

    Electron probe microanalysis (EPMA) is an essential analytical approach to determine elemental concentrations of various solid specimens quantitatively in mineralogical, petrological and materials research. Either wavelength dispersive X-ray (WDS) or energy dispersive X-ray (EDS) spectrometric techniques can collect the characteristic X-rays generated from each element in the specimen by an incident electron beam in order to define chemical constituents. Although WDS has been the preferred technique because of its higher spectral resolution and ability to detect trace elements, new generation EDS systems with silicon drift detectors (SDD), equipped with thin windows and integrated digital processing electronics, are claimed to approach the WDS throughput. In this study, we compared the analytical capability of a SDD EDS system with respect to WDS equipped systems on natural silicate minerals. For this purpose, natural rock samples, in which the silicate minerals present had already been analysed by various WDS systems, were chosen to compare these results with the ones acquired with a SDD EDS system. SDD EDS yielded satisfactory results for major elements (Na, Mg, Al, Si, K, Ca, Ti, Mn and Fe) compared with the results of the same minerals obtained by various WDS systems.

  2. The toxicity of chemical pollutants in dynamic natural systems: the challenge of integrating environmental factors and biological complexity.

    Science.gov (United States)

    Fischer, Beat B; Pomati, Francesco; Eggen, Rik I L

    2013-04-01

    The dynamics of abiotic and biotic environmental factors, like temperature and predation, can strongly influence the effects of anthropogenic chemical pollutants in natural systems. Responses to toxicants and their interactions with environmental factors can occur at varying temporal scales and at different levels of biological complexity (from cells to organisms, populations, communities and ecosystems). Environmental factors may affect tolerance to toxic pollutants under non-stressful conditions, and cause adverse multiple stressor effects under stressful conditions. Adaptive processes, however, have the potential to either mitigate (by co-tolerance) or increase (due to associated costs) the sensitivity of individuals, populations, and communities to pollutants through selection and evolution of traits (at the individual and population levels) and changes in species composition (at the community level). Responses to such multiple stressor effects on different biological levels and temporal scales are not considered in current risk assessment practices. We suggest that these effects should and can be addressed by: (i) designing ecotoxicological experiments with temporal exposure patterns that accommodate adaptive processes, (ii) using trait-based approaches to assess biological responses and natural selection in an integrated manner, and (iii) using energy allocation models to link responses at different levels of biological organization. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Impact of the changes in the chemical composition of pore water on chemical and physical stability of natural clays. A review of natural cases and related laboratory experiments and the ideas on natural analogues for bentonite erosion/non-erosion

    Energy Technology Data Exchange (ETDEWEB)

    Puura, Erik (Eridicon OUe, Tartu (Estonia)); Kirsimaee, Kalle (Univ. of Tartu, Inst. of Ecology and Earth Sciences, Tartu (Estonia))

    2010-01-15

    A scientific literature survey was compiled with the specific objective to find information for smectite mobilization and/or retention in natural clay formations caused by contact with water with low ionic concentrations such as can be expected during and after an ice age. Evidence was sought if smectite particles are lost from the clay to the water and if accessory minerals that remain could form a growing filter slowing down or stopping further loss of smectite. Bentonites are present in geological layers for hundreds of millions of years. There is limited exchange with surrounding layers, eg K transported into the bentonite layer from surrounding shale layers leading to the increased illite % in smectite-illite of the bentonite. Another process is silicification of surrounding layers leading to lowered permeability of surrounding rocks. Geological literature data on historical bentonites do not consider colloid formation in low ionic strength water as relevant mechanism for smectite mobilization. However there are no studied cases where this could be a relevant mechanism (as proposed by colloid release scenario). Soil researchers have studied the mechanism of colloid release in laboratory experiments and have found that there has to be an abrupt change in infiltrating water quality leading to 'osmotic explosion'. Clogging the pores in the lower part of the soil column has followed, leading to dramatic decrease of hydraulic conductivity in vertical profile and increased surface runoff. So, although limited, there are literature evidences of clay colloids release from bentonites/smectites caused by low-ionic circumneutral water. The geological settings to look for natural analogue studies include (1) Bentonite/smectite similar to what is used in repository. (2) Water similar to the composition of glacial meltwater. (3) Scenario similar to what is proposed in the bentonite erosion project. The problem related to the study of historical bentonite profiles

  4. Low Cost Chemical Feedstocks Using an Improved and Energy Efficient Natural Gas Liquid (NGL) Removal Process, Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Howard, S.; Lu, Yingzhong

    2012-08-10

    The overall objective of this project is to develop a new low-cost and energy efficient Natural Gas Liquid (NGL) recovery process - through a combination of theoretical, bench-scale and pilot-scale testing - so that it could be offered to the natural gas industry for commercialization. The new process, known as the IROA process, is based on U.S. patent No. 6,553,784, which if commercialized, has the potential of achieving substantial energy savings compared to currently used cryogenic technology. When successfully developed, this technology will benefit the petrochemical industry, which uses NGL as feedstocks, and will also benefit other chemical industries that utilize gas-liquid separation and distillation under similar operating conditions. Specific goals and objectives of the overall program include: (i) collecting relevant physical property and Vapor Liquid Equilibrium (VLE) data for the design and evaluation of the new technology, (ii) solving critical R&D issues including the identification of suitable dehydration and NGL absorbing solvents, inhibiting corrosion, and specifying proper packing structure and materials, (iii) designing, construction and operation of bench and pilot-scale units to verify design performance, (iv) computer simulation of the process using commercial software simulation platforms such as Aspen-Plus and HYSYS, and (v) preparation of a commercialization plan and identification of industrial partners that are interested in utilizing the new technology. NGL is a collective term for C2+ hydrocarbons present in the natural gas. Historically, the commercial value of the separated NGL components has been greater than the thermal value of these liquids in the gas. The revenue derived from extracting NGLs is crucial to ensuring the overall profitability of the domestic natural gas production industry and therefore of ensuring a secure and reliable supply in the 48 contiguous states. However, rising natural gas prices have dramatically reduced

  5. Pharmaceuticals May Disrupt Natural Chemical Information Flows and Species Interactions in Aquatic Systems: Ideas and Perspectives on a Hidden Global Change.

    Science.gov (United States)

    Van Donk, Ellen; Peacor, Scott; Grosser, Katharina; De Senerpont Domis, Lisette N; Lürling, Miquel

    Pharmaceuticals consumption by humans and animals is increasing substantially, leading to unprecedented levels of these compounds in aquatic environments worldwide. Recent findings that concentrations reach levels that can directly have negative effects on organisms are important per se, but also sound an alarm for other potentially more pervasive effects that arise from the interconnected nature of ecological communities. Aquatic organisms use chemical cues to navigate numerous challenges, including the location of mates and food, and the avoidance of natural enemies. Low concentrations of pharmaceuticals can disrupt this "smellscape" of information leading to maladaptive responses. Furthermore, direct effects of pharmaceuticals on the traits and abundance of one species can cascade through a community, indirectly affecting other species. We review mechanisms by which pharmaceuticals in surface waters can disrupt natural chemical information flows and species interactions. Pharmaceuticals form a new class of chemical threats, which could have far-reaching implications for ecosystem functioning and conservation management.

  6. VirtualToxLab — A platform for estimating the toxic potential of drugs, chemicals and natural products

    Energy Technology Data Exchange (ETDEWEB)

    Vedani, Angelo, E-mail: angelo.vedani@unibas.ch [Biographics Laboratory 3R, Klingelbergstrasse 50, 4056 Basel (Switzerland); Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel (Switzerland); Dobler, Max [Biographics Laboratory 3R, Klingelbergstrasse 50, 4056 Basel (Switzerland); Smieško, Martin [Department of Pharmaceutical Sciences, University of Basel, Klingelbergstrasse 50, 4056 Basel (Switzerland)

    2012-06-01

    The VirtualToxLab is an in silico technology for estimating the toxic potential (endocrine and metabolic disruption, some aspects of carcinogenicity and cardiotoxicity) of drugs, chemicals and natural products. The technology is based on an automated protocol that simulates and quantifies the binding of small molecules towards a series of proteins, known or suspected to trigger adverse effects. The toxic potential, a non-linear function ranging from 0.0 (none) to 1.0 (extreme), is derived from the individual binding affinities of a compound towards currently 16 target proteins: 10 nuclear receptors (androgen, estrogen α, estrogen β, glucocorticoid, liver X, mineralocorticoid, peroxisome proliferator-activated receptor γ, progesterone, thyroid α, and thyroid β), four members of the cytochrome P450 enzyme family (1A2, 2C9, 2D6, and 3A4), a cytosolic transcription factor (aryl hydrocarbon receptor) and a potassium ion channel (hERG). The interface to the technology allows building and uploading molecular structures, viewing and downloading results and, most importantly, rationalizing any prediction at the atomic level by interactively analyzing the binding mode of a compound with its target protein(s) in real-time 3D. The VirtualToxLab has been used to predict the toxic potential for over 2500 compounds: the results are posted on (http://www.virtualtoxlab.org). The free platform — the OpenVirtualToxLab — is accessible (in client–server mode) over the Internet. It is free of charge for universities, governmental agencies, regulatory bodies and non-profit organizations. -- Highlights: ► In silico technology for estimating the toxic potential of drugs and chemicals. ► Simulation of binding towards 16 proteins suspected to trigger adverse effects. ► Mechanistic interpretation and real-time 3D visualization. ► Accessible over the Internet. ► Free of charge for universities, governmental agencies, regulatory bodies and NPOs.

  7. In vitro antimicrobial activity of auxiliary chemical substances and natural extracts on Candida albicans and Enterococcus faecalis in root canals

    Science.gov (United States)

    VALERA, Marcia Carneiro; MAEKAWA, Lilian Eiko; de OLIVEIRA, Luciane Dias; JORGE, Antonio Olavo Cardoso; SHYGEI, Érika; CARVALHO, Cláudio Antonio Talge

    2013-01-01

    Objective: The aim of this study was to evaluate the antimicrobial activity of auxiliary chemical substances and natural extracts on Candida albicans and Enterococcus faecalis inoculated in root canals. Material and Methods: Seventy-two human tooth roots were contaminated with C. albicans and E. faecalis for 21 days. The groups were divided according to the auxiliary chemical substance into: G1) 2.5% sodium hypochlorite (NaOCl), G2) 2% chlorhexidine gel (CHX), G3) castor oil, G4) glycolic Aloe vera extract, G5) glycolic ginger extract, and G6) sterile saline (control). The samples of the root canal were collected at different intervals: confirmation collection, at 21 days after contamination; 1st collection, after instrumentation; and 2nd collection, seven days after instrumentation. Microbiological samples were grown in culture medium and incubated at 37º C for 48 hours. Results: The results were submitted to the Kruskal-Wallis and Dunn (5%) statistical tests. NaOCl and CHX completely eliminated the microorganisms of the root canals. Castor oil and ginger significantly reduced the number of CFU of the tested bacteria. Reduction of CFU/mL at the 1st and 2nd collections for groups G1, G2, G3 and G4 was greater in comparison to groups G5 and G6. Conclusion: It was concluded that 2.5% sodium hypochlorite and 2% chlorhexidine gel were more effective in eliminating C. albicans and E. faecalis, followed by the castor oil and glycolic ginger extract. The Aloe vera extract showed no antimicrobial activity. PMID:23739849

  8. Effects of Sterilization on the Physico-Chemical Properties of Natural Sediments From the Oak Ridge Reservation

    Energy Technology Data Exchange (ETDEWEB)

    Bank, T.L.; Kukkadapu, R.K.; Madden, A.S.; Ginder-Vogel, M.A.; Baldwin, M.E.; Jardine, P.M.

    2009-04-29

    Batch U(VI) sorption/reduction experiments were completed on sterilized and non-sterilized sediment samples to elucidate biological and geochemical reduction mechanisms. Results from X-ray absorption near-edge structure (XANES) spectroscopy revealed that {gamma}-sterilized sediments were actually better sorbents of U(VI), despite the absence of any measurable biological activity. These results indicate that {gamma}-irradiation induced significant physico-chemical changes in the sediment which is contrary to numerous other studies identifying {gamma}-sterilization as an effective and minimally invasive technique. To identify the extent and method of alteration of the soil as a result of {gamma}-sterilization, untreated soil samples, physically separated size fractions, and chemically extracted fractions of the soil were analyzed pre- and post-sterilization. The effects of sterilization on mineralogy, pH, natural organic matter (NOM), cation exchange capacity (CEC), and iron oxidation state were determined. Results indicated that major mineralogy of the clay and whole sediment samples was unchanged. Sediment pH decreased only slightly with {gamma}-irradiation; however, irradiation produced a significant decrease in CEC of the untreated sediments and affected both the organic and inorganic fractions. Moessbauer spectra of non-sterile and {gamma}-sterilized sediments measured more reduced iron present in {gamma}-sterilized sediments compared to non-sterile samples. Our results suggest that sterilization by {gamma}-irradiation induced iron reduction that may have increased the sorption and/or reduction of U(VI) onto these sediments. However, Moessbauer and batch sorption data are somewhat contradictory, the former indicates that the iron oxide or iron hydroxide minerals are more significantly reduced while the later indicates that reduced clay minerals account for greater sorption of U(VI).

  9. In vitro antimicrobial activity of auxiliary chemical substances and natural extracts on Candida albicans and Enterococcus faecalis in root canals

    Directory of Open Access Journals (Sweden)

    Marcia Carneiro Valera

    2013-04-01

    Full Text Available Objective: The aim of this study was to evaluate the antimicrobial activity of auxiliary chemical substances and natural extracts on Candida albicans and Enterococcus faecalis inoculated in root canals. Material and Methods: Seventy-two human tooth roots were contaminated with C. albicans and E. faecalis for 21 days. The groups were divided according to the auxiliary chemical substance into: G1 2.5% sodium hypochlorite (NaOCl, G2 2% chlorhexidine gel (CHX, G3 castor oil, G4 glycolic Aloe vera extract, G5 glycolic ginger extract, and G6 sterile saline (control. The samples of the root canal were collected at different intervals: confirmation collection, at 21 days after contamination; 1st collection, after instrumentation; and 2nd collection, seven days after instrumentation. Microbiological samples were grown in culture medium and incubated at 37°C for 48 hours. Results: The results were submitted to the Kruskal-Wallis and Dunn (5% statistical tests. NaOCl and CHX completely eliminated the microorganisms of the root canals. Castor oil and ginger significantly reduced the number of CFU of the tested bacteria. Reduction of CFU/mL at the 1st and 2nd collections for groups G1, G2, G3 and G4 was greater in comparison to groups G5 and G6. Conclusion: It was concluded that 2.5% sodium hypochlorite and 2% chlorhexidine gel were more effective in eliminating C. albicans and E. faecalis, followed by the castor oil and glycolic ginger extract. The Aloe vera extract showed no antimicrobial activity.

  10. An Introduction to the Foundations of Chemical Information Theory. Tarski–Lesniewski Logical Structures and the Organization of Natural Sorts and Kinds

    Directory of Open Access Journals (Sweden)

    Jerry L. R. Chandler

    2017-01-01

    Full Text Available Organic mathematics is an applied mathematics of philosophical atomism. The order of the chemical elements in the table of elements is the source of order for the logical operations of addition and subtraction of atomic numbers. The inverse square laws of physics are the source of organization of subatomic structures of chemical atoms (atomic and molecular structures. These facts are foundational to the logic of the chemical sciences and are therefore the scientific basis for chemical information theory. The theories and facts of the chemical sciences are so perplex that several forms of symbolic representations are necessary to communicate the broad range of scientific concepts used to inquire into the nature of natural sorts and kinds. The logics proposed by Tarski, Lesniewski and Malatesta are applied to the construction of a numerical “spine” of perplex numbers representing atomic numbers as meta-symbols in meta-languages. The orbital angular momenta of certain collections of electrical particles (also known as “handedness” are critical components in constructing the logical propositions of the perplex number “spine”. Biological communication channels can function if and only if the natural sorts and kinds are consistent with the matching patterns of the optical isomers. The terms spinners and twisters are introduced to express the electro-mechanical torques necessary for encoding chemical information. This hypothesis can be tested by several categories of experiments, including clinical pharmaco-dynamics and clinical toxico-dynamics of dissymmetric isomers of different sorts and kinds.

  11. Biological effects of some natural and chemical compounds on the potato tuber moth, Phthorimaea operculella Zell. (Lepidoptera:Gelechiidae)

    Science.gov (United States)

    Sharaby, Aziza; Abdel-Rahman, H.; Moawad, S.

    2009-01-01

    The olfactory reaction of larvae and moths was investigated towards 18 oils (6 natural oils and 12 commercial chemical oils). Some of these oils such as peppermint and camphor (natural oils) and eugenol and camphene (commercial oils) were repellent to both larvae and moths. Other oils such as strawberry and d-limonene were attractive to both larvae and moths. Some of the repellent oils were, therefore, tested for their effect on certain biological aspects of the insects. Eugenol and peppermint oils, each at the 0.01% conc., caused a significant depression in the fecundity of moth and decreased the percentage of egg hatchability. Eugenol oil was much more effective than peppermint oil at 1%. Dried (leaves, fruits or seeds) powder of 14 different plants species were tested in different concentrations with talcum powder (carrier material) against egg deposition. The results indicated that dried powders of Allium cepa, Curcuma longa, Colocasia antiqurum, Ocimum basilicum. Dodonaea viscose and Thuja orientalis played a highly significant role in reducing egg deposition. The most impressive effect was displayed by powders of D. viscose and A. cepa, which caused the highest depression in egg deposition as well as in the emerging offsprings. Ethanolic extracts of 11 plants indicated that extracts of Pithuranthos tortosus and Iphiona scabra caused the maximum inhibition of egg hatchability, followed by C. longa, Citrullus colocynthia and T. orientalis. Ethanolic extracts of Schinus terebenthiflius (leaves) and I. scabra caused the highest depression in the deposited eggs, as they played a remarkable role as ovipositor deterrents. The majority of the plant extracts at 1% conc. could protect potato tubers at different intervals according to the calculated tuber damage index as follows: Iphiopna > Pithuranthos > Curcuma > Schinus (fruits) Thuja > Schinus (leaves) > Dodonaea > Citrullus. PMID:23961036

  12. MHD Natural Convection Flow of Casson Nanofluid over Nonlinearly Stretching Sheet Through Porous Medium with Chemical Reaction and Thermal Radiation.

    Science.gov (United States)

    Ullah, Imran; Khan, Ilyas; Shafie, Sharidan

    2016-12-01

    In the present work, the effects of chemical reaction on hydromagnetic natural convection flow of Casson nanofluid induced due to nonlinearly stretching sheet immersed in a porous medium under the influence of thermal radiation and convective boundary condition are performed numerically. Moreover, the effects of velocity slip at stretching sheet wall are also examined in this study. The highly nonlinear-coupled governing equations are converted to nonlinear ordinary differential equations via similarity transformations. The transformed governing equations are then solved numerically using the Keller box method and graphical results for velocity, temperature, and nanoparticle concentration as well as wall shear stress, heat, and mass transfer rate are achieved through MATLAB software. Numerical results for the wall shear stress and heat transfer rate are presented in tabular form and compared with previously published work. Comparison reveals that the results are in good agreement. Findings of this work demonstrate that Casson fluids are better to control the temperature and nanoparticle concentration as compared to Newtonian fluid when the sheet is stretched in a nonlinear way. Also, the presence of suspended nanoparticles effectively promotes the heat transfer mechanism in the base fluid.

  13. Analysis of Combined Cycle Power Plants with Chemical Looping Reforming of Natural Gas and Pre-Combustion CO2 Capture

    Directory of Open Access Journals (Sweden)

    Shareq Mohd Nazir

    2018-01-01

    Full Text Available In this paper, a gas-fired combined cycle power plant subjected to a pre-combustion CO2 capture method has been analysed under different design conditions and different heat integration options. The power plant configuration includes the chemical looping reforming (CLR of natural gas (NG, water gas shift (WGS process, CO2 capture and compression, and a hydrogen fuelled combined cycle to produce power. The process is denoted as a CLR-CC process. One of the main parameters that affects the performance of the process is the pressure for the CLR. The process is analysed at different design pressures for the CLR, i.e., 5, 10, 15, 18, 25 and 30 bar. It is observed that the net electrical efficiency increases with an increase in the design pressure in the CLR. Secondly, the type of steam generated from the cooling of process streams also effects the net electrical efficiency of the process. Out of the five different cases including the base case presented in this study, it is observed that the net electrical efficiency of CLR-CCs can be improved to 46.5% (lower heating value of NG basis by producing high-pressure steam through heat recovery from the pre-combustion process streams and sending it to the Heat Recovery Steam Generator in the power plant.

  14. The facts that the physical-chemical properties of modern tablets distinguish them from natural food lumps

    Science.gov (United States)

    Urakov, A.; Urakova, N.; Reshetnikov, A.; Kopylov, M.; Kasatkin, A.; Baymurzin, D.; Gabdrafikov, R.

    2017-02-01

    It was found that pharmaceutical companies produce drugs in tablet form, physical or physical-chemical properties that are radically different from those of the properties of natural food lumps, in that adult converts food in our mouth before swallowing. It was shown that the conventional shape, color, size, volume, specific gravity, hardness, osmotic and acid activity of modern tablets impair the physical and physicochemical properties of the liquid contents of the stomach is much stronger than such “building” materials, such as chalk, clay, sand, river pebbles and gravel. The results showed, that the value of the specific hardness, deforming tablets, can distinguish modern tablets from each other by more than 5000 times. Therefore, introduction tablets inside without information of ability injuring their action leads to the fact that soft and “unsalted” tablets almost nothing damage, and too “salty” and solid tablets damage the gums, lips, tongue, teeth and dental structures. To reduce the traumatic action tablets offered standardize osmoticity, corrosion and hardness within the range of safe values for soft and hard tissues of the oral cavity and improve standard introduction of tablets in the mouth.

  15. Chemical modification

    Science.gov (United States)

    R. M. Rowell

    2004-01-01

    Wood is a hygroscopic resource that was designed to perform, in nature, in a wet environment. Nature is programmed to recycle wood in a timely way through biological, thermal, aqueous, photochemical, chemical, and mechanical degradations. In simple terms, nature builds wood from carbon dioxide and water and has all the tools to recycle it back to the starting chemicals...

  16. Correct Models

    OpenAIRE

    Blacher, René

    2010-01-01

    Ce rapport complete les deux rapports précédents et apporte une explication plus simple aux résultats précédents : à savoir la preuve que les suites obtenues sont aléatoires.; In previous reports, we have show how to transform a text $y_n$ in a random sequence by using functions of Fibonacci $T_q$. Now, in this report, we obtain a clearer result by proving that $T_q(y_n)$ has the IID model as correct model. But, it is necessary to define correctly a correct model. Then, we study also this pro...

  17. [Clinical significance of corrected sinus node recovery time and natural and unnatural history of sinus node dysfunctions. A four-year prospective follow-up of 101 cases].

    Science.gov (United States)

    Raviele, A; Di Pede, F; Zuin, G; Callegari, E; Delise, P; Pascotto, P; D'Este, D; Dainese, F; Piccolo, E

    1982-01-01

    The clinical significance of corrected sinus node recovery time (CSNRT) and the natural and unnatural history of sinus node dysfunctions are not completely known. To gain some insight into this problem, 101 patients (pts) (54M, 47F, mean age +/- SD = 62.02 yrs +/- 14.42) with clinical and ECG signs of definite or suspected sick sinus syndrome (SSS) underwent an electrophysiologic study and then were prospectively followed for a mean period of 44.36 months +/- 18.96 (range: 2-78 months). The pts were divided into two groups: 1) Group A: 68 pts with prolonged CSNRT (greater than 500 msec); 2) Group B: 33 pts with normal CSNRT. Thirty-three pts of Group A (48.5%) and 2 pts of Group B (6.1%) received VVI pacemaker implantation (PM) immediately after the electrophysiologic study. The following results were obtained: 1) Pts of Group A showed a higher prevalence of organic heart disease and of ECG signs of definite SSS than pts of Group B. (p less than 0.05). Moreover, the higher the CSNRT in Group A pts, the more severe the ECG abnormalities of SSS. 2) Pts without PM, both of Group A and Group B, noted during the follow-up period a disappearance of neurological symptoms (syncopes and/or dizziness) and of ECG abnormalities of SSS in more than 50% of the cases. However, this was less evident in Group A pts compared with Group B pts (53.8% vs 78.6% regarding neurological symptoms and 54.3% vs 74.1% regarding ECG abnormalities of SSS) as well as in pts with organic heart disease in comparison with those with primitive SSS. Moreover, the number of pts who needed PM implantation during the follow-up period due to the worsening of clinical and ECG signs of SSS were higher in Group A than in Group B (20% vs 6.5%). The occurrence of cardiac death among the pts without PM was similar in pts of Group A (8.5%) and in those of Group B (9.7%). One pt of Group A without PM died suddenly (less than 1 hour). 3) Pts who required PM implantation were older (p less than 0.01) and showed a

  18. Assessment of multiple sources of anthropogenic and natural chemical inputs to a morphologically complex basin, Lake Mead, USA

    Science.gov (United States)

    Rosen, Michael R.; Van Metre, P.C.

    2010-01-01

    Lakes with complex morphologies and with different geologic and land-use characteristics in their sub-watersheds could have large differences in natural and anthropogenic chemical inputs to sub-basins in the lake. Lake Mead in southern Nevada and northern Arizona, USA, is one such lake. To assess variations in chemical histories from 1935 to 1998 for major sub-basins of Lake Mead, four sediment cores were taken from three different parts of the reservoir (two from Las Vegas Bay and one from the Overton Arm and Virgin Basin) and analyzed for major and trace elements, radionuclides, and organic compounds. As expected, anthropogenic contaminant inputs are greatest to Las Vegas Bay reflecting inputs from the Las Vegas urban area, although concentrations are low compared to sediment quality guidelines and to other USA lakes. One exception to this pattern was higher Hg in the Virgin Basin core. The Virgin Basin core is located in the main body of the lake (Colorado River channel) and is influenced by the hydrology of the Colorado River, which changed greatly with completion of Glen Canyon Dam upstream in 1963. Major and trace elements in the core show pronounced shifts in the early 1960s and, in many cases, gradually return to concentrations more typical of pre-1960s by the 1980s and 1990s, after the filling of Lake Powell. The Overton Arm is the sub-basin least effected by anthropogenic contaminant inputs but has a complex 137Cs profile with a series of large peaks and valleys over the middle of the core, possibly reflecting fallout from nuclear tests in the 1950s at the Nevada Test Site. The 137Cs profile suggests a much greater sedimentation rate during testing which we hypothesize results from greatly increased dust fall on the lake and Virgin and Muddy River watersheds. The severe drought in the southwestern USA during the 1950s might also have played a role in variations in sedimentation rate in all of the cores. ?? 2009.

  19. Nitric oxide and nitrous oxide turnover in natural and engineered microbial communities: biological pathways, chemical reactions, and novel technologies

    Science.gov (United States)

    Schreiber, Frank; Wunderlin, Pascal; Udert, Kai M.; Wells, George F.

    2012-01-01

    Nitrous oxide (N2O) is an environmentally important atmospheric trace gas because it is an effective greenhouse gas and it leads to ozone depletion through photo-chemical nitric oxide (NO) production in the stratosphere. Mitigating its steady increase in atmospheric concentration requires an understanding of the mechanisms that lead to its formation in natural and engineered microbial communities. N2O is formed biologically from the oxidation of hydroxylamine (NH2OH) or the reduction of nitrite (NO−2) to NO and further to N2O. Our review of the biological pathways for N2O production shows that apparently all organisms and pathways known to be involved in the catabolic branch of microbial N-cycle have the potential to catalyze the reduction of NO−2 to NO and the further reduction of NO to N2O, while N2O formation from NH2OH is only performed by ammonia oxidizing bacteria (AOB). In addition to biological pathways, we review important chemical reactions that can lead to NO and N2O formation due to the reactivity of NO−2, NH2OH, and nitroxyl (HNO). Moreover, biological N2O formation is highly dynamic in response to N-imbalance imposed on a system. Thus, understanding NO formation and capturing the dynamics of NO and N2O build-up are key to understand mechanisms of N2O release. Here, we discuss novel technologies that allow experiments on NO and N2O formation at high temporal resolution, namely NO and N2O microelectrodes and the dynamic analysis of the isotopic signature of N2O with quantum cascade laser absorption spectroscopy (QCLAS). In addition, we introduce other techniques that use the isotopic composition of N2O to distinguish production pathways and findings that were made with emerging molecular techniques in complex environments. Finally, we discuss how a combination of the presented tools might help to address important open questions on pathways and controls of nitrogen flow through complex microbial communities that eventually lead to N2O build

  20. Nitric oxide and nitrous oxide turnover in natural and engineered microbial communities: biological pathways, chemical reactions and novel technologies

    Directory of Open Access Journals (Sweden)

    Frank eSchreiber

    2012-10-01

    Full Text Available Nitrous oxide (N2O is an environmentally important atmospheric trace gas because it is an effective greenhouse gas and it leads to ozone depletion through photo-chemical nitric oxide (NO production in the stratosphere. Mitigating its steady increase in atmospheric concentration requires an understanding of the mechanisms that lead to its formation in natural and engineered microbial communities. N2O is formed biologically from the oxidation of hydroxylamine (NH2OH or the reduction of nitrite (NO2- to NO and further to N2O. Our review of the biological pathways for N2O production shows that apparently all organisms and pathways known to be involved in the catabolic branch of microbial N-cycle have the potential to catalyze the reduction of NO2- to NO and the further reduction of NO to N2O, while N2O formation from NH2OH is only performed by ammonia oxidizing bacteria. In addition to biological pathways, we review important chemical reactions that can lead to NO and N2O formation due to the reactivity of NO2-, NH2OH and nitroxyl (HNO. Moreover, biological N2O formation is highly dynamic in response to N-imbalance imposed on a system. Thus, understanding NO formation and capturing the dynamics of NO and N2O build-up are key to understand mechanisms of N2O release. Here, we discuss novel technologies that allow experiments on NO and N2O formation at high temporal resolution, namely NO and N2O microelectrodes and the dynamic analysis of the isotopic signature of N2O with quantum cascade laser based absorption spectroscopy. In addition, we introduce other techniques that use the isotopic composition of N2O to distinguish production pathways and findings that were made with emerging molecular techniques in complex environments. Finally, we discuss how a combination of the presented tools might help to address important open questions on pathways and controls of nitrogen flow through complex microbial communities that eventually lead to N2O build-up.

  1. Effects of Jigsaw Cooperative Learning and Animation Techniques on Students' Understanding of Chemical Bonding and Their Conceptions of the Particulate Nature of Matter

    Science.gov (United States)

    Karacop, Ataman; Doymus, Kemal

    2013-01-01

    The aim of this study was to determine the effect of jigsaw cooperative learning and computer animation techniques on academic achievements of first year university students attending classes in which the unit of chemical bonding is taught within the general chemistry course and these students' learning of the particulate nature of matter of this…

  2. Short-Term and Long-Term Biological Effects of Chronic Chemical Contamination on Natural Populations of a Marine Bivalve.

    Science.gov (United States)

    Breitwieser, Marine; Viricel, Amélia; Graber, Marianne; Murillo, Laurence; Becquet, Vanessa; Churlaud, Carine; Fruitier-Arnaudin, Ingrid; Huet, Valérie; Lacroix, Camille; Pante, Eric; Le Floch, Stéphane; Thomas-Guyon, Hélène

    2016-01-01

    Understanding the effects of chronic chemical contamination on natural populations of marine organisms is complex due to the combined effects of different types of pollutants and environmental parameters that can modulate the physiological responses to stress. Here, we present the effects of a chronic contamination in a marine bivalve by combining multiple approaches that provide information on individual and population health. We sampled variegated scallops (Mimachlamys varia) at sites characterized by different contaminants and contamination levels to study the short and long-term (intergenerational) responses of this species to physiological stress. We used biomarkers (SOD, MDA, GST, laccase, citrate synthase and phosphatases) as indicators of oxidative stress, immune system alteration, mitochondrial respiration and general metabolism, and measured population genetic diversity at each site. In parallel, concentration of 14 trace metals and 45 organic contaminants (PAHs, PCBs, pesticides) in tissues were measured. Scallops were collected outside and during their reproductive season to investigate temporal variability in contaminant and biomarker levels. Our analyses revealed that the levels of two biomarkers (Laccase-type phenoloxidase and malondialdehyde) were significantly correlated with Cd concentration. Additionally, we observed significant seasonal differences for four of the five biomarkers, which is likely due to the scallop reproductive status at time of sampling. As a source of concern, a location that was identified as a reference site on the basis of inorganic contaminant levels presented the same level of some persistent organic pollutants (DDT and its metabolites) than more impacted sites. Finally, potential long-term effects of heavy metal contamination were observed for variegated scallops as genetic diversity was depressed in the most polluted sites.

  3. Short-Term and Long-Term Biological Effects of Chronic Chemical Contamination on Natural Populations of a Marine Bivalve.

    Directory of Open Access Journals (Sweden)

    Marine Breitwieser

    Full Text Available Understanding the effects of chronic chemical contamination on natural populations of marine organisms is complex due to the combined effects of different types of pollutants and environmental parameters that can modulate the physiological responses to stress. Here, we present the effects of a chronic contamination in a marine bivalve by combining multiple approaches that provide information on individual and population health. We sampled variegated scallops (Mimachlamys varia at sites characterized by different contaminants and contamination levels to study the short and long-term (intergenerational responses of this species to physiological stress. We used biomarkers (SOD, MDA, GST, laccase, citrate synthase and phosphatases as indicators of oxidative stress, immune system alteration, mitochondrial respiration and general metabolism, and measured population genetic diversity at each site. In parallel, concentration of 14 trace metals and 45 organic contaminants (PAHs, PCBs, pesticides in tissues were measured. Scallops were collected outside and during their reproductive season to investigate temporal variability in contaminant and biomarker levels. Our analyses revealed that the levels of two biomarkers (Laccase-type phenoloxidase and malondialdehyde were significantly correlated with Cd concentration. Additionally, we observed significant seasonal differences for four of the five biomarkers, which is likely due to the scallop reproductive status at time of sampling. As a source of concern, a location that was identified as a reference site on the basis of inorganic contaminant levels presented the same level of some persistent organic pollutants (DDT and its metabolites than more impacted sites. Finally, potential long-term effects of heavy metal contamination were observed for variegated scallops as genetic diversity was depressed in the most polluted sites.

  4. The nature of alarm communication in Constrictotermes cyphergaster (Blattodea: Termitoidea: Termitidae): the integration of chemical and vibroacoustic signals.

    Science.gov (United States)

    Cristaldo, Paulo F; Jandák, Vojtĕch; Kutalová, Kateřina; Rodrigues, Vinícius B; Brothánek, Marek; Jiříček, Ondřej; DeSouza, Og; Šobotník, Jan

    2015-11-04

    Alarm signalling is of paramount importance to communication in all social insects. In termites, vibroacoustic and chemical alarm signalling are bound to operate synergistically but have never been studied simultaneously in a single species. Here, we inspected the functional significance of both communication channels in Constrictotermes cyphergaster (Termitidae: Nasutitermitinae), confirming the hypothesis that these are not exclusive, but rather complementary processes. In natural situations, the alarm predominantly attracts soldiers, which actively search for the source of a disturbance. Laboratory testing revealed that the frontal gland of soldiers produces a rich mixture of terpenoid compounds including an alarm pheromone. Extensive testing led to identification of the alarm pheromone being composed of abundant monoterpene hydrocarbons (1S)-α-pinene and myrcene, along with a minor component, (E)-β-ocimene. The vibratory alarm signalling consists of vibratory movements evidenced as bursts; a series of beats produced predominantly by soldiers. Exposing termite groups to various mixtures containing the alarm pheromone (crushed soldier heads, frontal gland extracts, mixture of all monoterpenes, and the alarm pheromone mixture made of standards) resulted in significantly higher activity in the tested groups and also increased intensity of the vibratory alarm communication, with the responses clearly dose-dependent. Lower doses of the pheromone provoked higher numbers of vibratory signals compared to higher doses. Higher doses induced long-term running of all termites without stops necessary to perform vibratory behaviour. Surprisingly, even crushed worker heads led to low (but significant) increases in the alarm responses, suggesting that other unknown compound in the worker's head is perceived and answered by termites. Our results demonstrate the existence of different alarm levels in termites, with lower levels being communicated through vibratory signals, and

  5. The nature of alarm communication in Constrictotermes cyphergaster (Blattodea: Termitoidea: Termitidae: the integration of chemical and vibroacoustic signals

    Directory of Open Access Journals (Sweden)

    Paulo F. Cristaldo

    2015-12-01

    Full Text Available Alarm signalling is of paramount importance to communication in all social insects. In termites, vibroacoustic and chemical alarm signalling are bound to operate synergistically but have never been studied simultaneously in a single species. Here, we inspected the functional significance of both communication channels in Constrictotermes cyphergaster (Termitidae: Nasutitermitinae, confirming the hypothesis that these are not exclusive, but rather complementary processes. In natural situations, the alarm predominantly attracts soldiers, which actively search for the source of a disturbance. Laboratory testing revealed that the frontal gland of soldiers produces a rich mixture of terpenoid compounds including an alarm pheromone. Extensive testing led to identification of the alarm pheromone being composed of abundant monoterpene hydrocarbons (1S-α-pinene and myrcene, along with a minor component, (E-β-ocimene. The vibratory alarm signalling consists of vibratory movements evidenced as bursts; a series of beats produced predominantly by soldiers. Exposing termite groups to various mixtures containing the alarm pheromone (crushed soldier heads, frontal gland extracts, mixture of all monoterpenes, and the alarm pheromone mixture made of standards resulted in significantly higher activity in the tested groups and also increased intensity of the vibratory alarm communication, with the responses clearly dose-dependent. Lower doses of the pheromone provoked higher numbers of vibratory signals compared to higher doses. Higher doses induced long-term running of all termites without stops necessary to perform vibratory behaviour. Surprisingly, even crushed worker heads led to low (but significant increases in the alarm responses, suggesting that other unknown compound in the worker's head is perceived and answered by termites. Our results demonstrate the existence of different alarm levels in termites, with lower levels being communicated through

  6. Chemical reactivity of C-F bonds attached to graphene with diamines depending on their nature and location.

    Science.gov (United States)

    Li, Baoyin; He, Taijun; Wang, Zaoming; Cheng, Zheng; Liu, Yang; Chen, Teng; Lai, Wenchuan; Wang, Xu; Liu, Xiangyang

    2016-06-29

    The attachment of fluorine to graphene is a facile means to activate the carbon bonds for subsequent covalent bonding to other molecules for the preparation of desired graphene derivatives. Therefore, an insight into the chemical reactivity of fluorinated graphene (FG) is very essential to enable precise control of the composition and structure of the final products. In this study, FG has been treated with various mass amounts of poly(oxypropylene)diamine (PEA) ranging from starvation to saturation to explore the dependence of a substitution reaction of diamines on the nature and location (attached onto the basal planes or along defects or edges) of C-F bonds. X-ray photoelectron spectroscopy directly tracked the atomic percentage of fluorine present and the carbon 1s bonding state, showing that the grafting ratio of diamines gradually increases with increased diamine mass ratio. The varying of the types and orientation of C-F bonds characterized by polarized attenuated total reflectance Fourier transform infrared spectroscopy indicates that "covalent" C-F bonds are more sensitive to the substitution reaction of diamines than ''semi-ionic'' C-F bonds, and the C-F bonds attached onto basal planes more preferably participate in the functionalization reaction of diamines than that of C-F bonded on non-coplanar regions (edges or defects). The one-dimensional expansion along the graphene c-axis shown by wide angle X-ray diffraction provides further evidence on the preferred functionalization reaction of C-F attached on the basal planes, resulting in a change of the average intersheet distance by various magnitudes.

  7. The nature of alarm communication in Constrictotermes cyphergaster (Blattodea: Termitoidea: Termitidae): the integration of chemical and vibroacoustic signals

    Science.gov (United States)

    Cristaldo, Paulo F.; Jandák, Vojtĕch; Kutalová, Kateřina; Rodrigues, Vinícius B.; Brothánek, Marek; Jiříček, Ondřej; DeSouza, Og; Šobotník, Jan

    2015-01-01

    ABSTRACT Alarm signalling is of paramount importance to communication in all social insects. In termites, vibroacoustic and chemical alarm signalling are bound to operate synergistically but have never been studied simultaneously in a single species. Here, we inspected the functional significance of both communication channels in Constrictotermes cyphergaster (Termitidae: Nasutitermitinae), confirming the hypothesis that these are not exclusive, but rather complementary processes. In natural situations, the alarm predominantly attracts soldiers, which actively search for the source of a disturbance. Laboratory testing revealed that the frontal gland of soldiers produces a rich mixture of terpenoid compounds including an alarm pheromone. Extensive testing led to identification of the alarm pheromone being composed of abundant monoterpene hydrocarbons (1S)-α-pinene and myrcene, along with a minor component, (E)-β-ocimene. The vibratory alarm signalling consists of vibratory movements evidenced as bursts; a series of beats produced predominantly by soldiers. Exposing termite groups to various mixtures containing the alarm pheromone (crushed soldier heads, frontal gland extracts, mixture of all monoterpenes, and the alarm pheromone mixture made of standards) resulted in significantly higher activity in the tested groups and also increased intensity of the vibratory alarm communication, with the responses clearly dose-dependent. Lower doses of the pheromone provoked higher numbers of vibratory signals compared to higher doses. Higher doses induced long-term running of all termites without stops necessary to perform vibratory behaviour. Surprisingly, even crushed worker heads led to low (but significant) increases in the alarm responses, suggesting that other unknown compound in the worker's head is perceived and answered by termites. Our results demonstrate the existence of different alarm levels in termites, with lower levels being communicated through vibratory

  8. If You Don't Have a Good Laboratory, Find a Good Volcano: Mount Vesuvius as a Natural Chemical Laboratory in Eighteenth-Century Italy.

    Science.gov (United States)

    Guerra, Corinna

    2015-08-01

    This essay that examines the role of the volcano as a chemical site in the late eighteenth century, as the "new chemistry" spread throughout the southern Italian Kingdom of Naples, resulting in lively debates. In Naples itself, these scientific debates were not confined to academies, courts, and urban spaces. In the absence of well-equipped chemical laboratories, Neapolitan scholars also carried out research on chemistry on the slopes of Mount Vesuvius, a natural site that furnished them with all the tools and substances necessary for practising chemistry. By examining various Neapolitan publications on Vesuvius and the chemical reactions and products associated with its periodic eruptions, I argue that the volcano's presence contributed to a distinctive, local approach to chemical theory and practice. Several case studies examine the ways in which proximity to Vesuvius was exploited by Neapolitan scholars as they engaged with the new chemistry, including Giuseppe Vairo, Michele Ferrara, Francesco Semmola, and Emanuele Scotti.

  9. Publisher Correction

    DEFF Research Database (Denmark)

    Flachsbart, Friederike; Dose, Janina; Gentschew, Liljana

    2018-01-01

    The original version of this Article contained an error in the spelling of the author Robert Häsler, which was incorrectly given as Robert Häesler. This has now been corrected in both the PDF and HTML versions of the Article....

  10. High-performance liquid chromatographic separation of natural and synthetic desulphoglucosinolates and their chemical validation by UV, NMR and chemical ionisation-MS methods.

    Science.gov (United States)

    Kiddle, G; Bennett, R N; Botting, N P; Davidson, N E; Robertson, A A; Wallsgrove, R M

    2001-01-01

    Methods are described for the optimised extraction, desulphation and HPLC separation of desulphoglucosinolates. These methods provide rapid separation, identification and quantitative measurements of glucosinolates extracted from Brassica napus L and related crops, of unusual glucosinolates found in crucifer weed species, and also of synthetic alkylglucosinolates. The desulphoglucosinolates used in these studies were either chemically synthesised (at least one example from each major structural class), or purified from various plant sources. Validation of the identities of the desulphoglucosinolates was by comparison of retention times with standards, and by UV, 1H- and 13C-NMR and chemical ionisation MS analysis. A list of useful species, and the specific tissues, from which high concentrations of standards can be extracted is included.

  11. ICT: isotope correction toolbox.

    Science.gov (United States)

    Jungreuthmayer, Christian; Neubauer, Stefan; Mairinger, Teresa; Zanghellini, Jürgen; Hann, Stephan

    2016-01-01

    Isotope tracer experiments are an invaluable technique to analyze and study the metabolism of biological systems. However, isotope labeling experiments are often affected by naturally abundant isotopes especially in cases where mass spectrometric methods make use of derivatization. The correction of these additive interferences--in particular for complex isotopic systems--is numerically challenging and still an emerging field of research. When positional information is generated via collision-induced dissociation, even more complex calculations for isotopic interference correction are necessary. So far, no freely available tools can handle tandem mass spectrometry data. We present isotope correction toolbox, a program that corrects tandem mass isotopomer data from tandem mass spectrometry experiments. Isotope correction toolbox is written in the multi-platform programming language Perl and, therefore, can be used on all commonly available computer platforms. Source code and documentation can be freely obtained under the Artistic License or the GNU General Public License from: https://github.com/jungreuc/isotope_correction_toolbox/ {christian.jungreuthmayer@boku.ac.at,juergen.zanghellini@boku.ac.at} Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  12. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment of jaws ... out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment of jaws ...

  13. Correction note.

    Science.gov (United States)

    2014-12-01

    Correction note for Sanders, M., Calam, R., Durand, M., Liversidge, T. and Carmont, S. A. (2008), Does self-directed and web-based support for parents enhance the effects of viewing a reality television series based on the Triple P - Positive Parenting Programme?. Journal of Child Psychology and Psychiatry, 49: 924-932. doi: 10.1111/j.1469-7610.2008.01901.x. © 2014 Association for Child and Adolescent Mental Health.

  14. TREATMENT OF HYDROCARBON, ORGANIC RESIDUE AND PRODUCTION CHEMICAL DAMAGE MECHANISMS THROUGH THE APPLICATION OF CARBON DIOXIDE IN NATURAL GAS STORAGE WELLS

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence J. Pekot; Ron Himes

    2004-05-31

    Core specimens and several material samples were collected from two natural gas storage reservoirs. Laboratory studies were performed to characterize the samples that were believed to be representative of a reservoir damage mechanism previously identified as arising from the presence of hydrocarbons, organic residues or production chemicals. A series of laboratory experiments were performed to identify the sample materials, use these materials to damage the flow capacity of the core specimens and then attempt to remove or reduce the induced damage using either carbon dioxide or a mixture of carbon dioxide and other chemicals. Results of the experiments showed that pure carbon dioxide was effective in restoring flow capacity to the core specimens in several different settings. However, in settings involving asphaltines as the damage mechanism, both pure carbon dioxide and mixtures of carbon dioxide and other chemicals provided little effectiveness in damage removal.

  15. The role and prospects of development of certified reference materials of chemical composition of natural and man-made environments in geoanalysis

    Directory of Open Access Journals (Sweden)

    I. E. Vasileva

    2016-01-01

    Full Text Available Emergence of requirements in the certified reference materials (CRMs to perform chemical analysis of natural and man-made environments (geoanalysis; and formation of requirements to accuracy of results and quality management systems analysis are shown in the historical aspect. Creation of the multi-parameter CRMs of composition, size and quantity of mineral phases for geoanalysis are presented as new outlook.

  16. Chemical correction of pre-mRNA splicing defects associated with sequestration of muscleblind-like 1 protein by expanded r(CAG) transcripts

    Science.gov (United States)

    Kumar, Amit; Parkesh, Raman; Sznajder, Lukasz J.; Childs-Disney, Jessica; Sobczak, Krzysztof; Disney, Matthew D.

    2012-01-01

    Recently, it was reported that expanded r(CAG) triplet repeats (r(CAG)exp) associated with untreatable neurological diseases cause pre-mRNA mis-splicing likely due to sequestration of muscleblind-like 1 (MBNL1) splicing factor. Bioactive small molecules that bind the 5’CAG/3’GAC motif found in r(CAG)exp hairpin structure were identified by using RNA binding studies and virtual screening/chemical similarity searching. Specifically, a benzylguanidine-containing small molecule was found to improve pre-mRNA alternative splicing of MBNL1-sensitive exons in cells expressing the toxic r(CAG)exp. The compound was identified by first studying the binding of RNA 1×1 nucleotide internal loops to small molecules known to have affinity for nucleic acids. Those studies identified 4',6-diamidino-2-phenylindole (DAPI) as a specific binder to RNAs with the 5’CAG/3’GAC motif. DAPI was then used as a query molecule in a shape- and chemistry alignment-based virtual screen to identify compounds with improved properties, which identified 4-guanidinophenyl 4-guanidinobenzoate as small molecule capable of improving pre-mRNA splicing defects associated with the r(CAG)exp-MBNL1 complex. This compound may facilitate the development of therapeutics to treat diseases caused by r(CAG)exp and could serve as a useful chemical tool to dissect the mechanisms of r(CAG)exp toxicity. The approach used in these studies, defining the small RNA motifs that bind known nucleic acid binders and then using virtual screening to optimize them for bioactivity, may be generally applicable for designing small molecules that target other RNAs in human genomic sequence. PMID:22252896

  17. Chemical correction of pre-mRNA splicing defects associated with sequestration of muscleblind-like 1 protein by expanded r(CAG)-containing transcripts.

    Science.gov (United States)

    Kumar, Amit; Parkesh, Raman; Sznajder, Lukasz J; Childs-Disney, Jessica L; Sobczak, Krzysztof; Disney, Matthew D

    2012-03-16

    Recently, it was reported that expanded r(CAG) triplet repeats (r(CAG)(exp)) associated with untreatable neurological diseases cause pre-mRNA mis-splicing likely due to sequestration of muscleblind-like 1 (MBNL1) splicing factor. Bioactive small molecules that bind the 5'CAG/3'GAC motif found in r(CAG)(exp) hairpin structure were identified by using RNA binding studies and virtual screening/chemical similarity searching. Specifically, a benzylguanidine-containing small molecule was found to improve pre-mRNA alternative splicing of MBNL1-sensitive exons in cells expressing the toxic r(CAG)(exp). The compound was identified by first studying the binding of RNA 1 × 1 nucleotide internal loops to small molecules known to have affinity for nucleic acids. Those studies identified 4',6-diamidino-2-phenylindole (DAPI) as a specific binder to RNAs with the 5'CAG/3'GAC motif. DAPI was then used as a query molecule in a shape- and chemistry alignment-based virtual screen to identify compounds with improved properties, which identified 4-guanidinophenyl 4-guanidinobenzoate, a small molecule that improves pre-mRNA splicing defects associated with the r(CAG)(exp)-MBNL1 complex. This compound may facilitate the development of therapeutics to treat diseases caused by r(CAG)(exp) and could serve as a useful chemical tool to dissect the mechanisms of r(CAG)(exp) toxicity. The approach used in these studies, defining the small RNA motifs that bind small molecules with known affinity for nucleic acids and then using virtual screening to optimize them for bioactivity, may be generally applicable for designing small molecules that target other RNAs in the human genomic sequence.

  18. IMPLICATIONS OF GLOBAL CLIMATE CHANGE FOR THE ASSESSMENT AND MANAGEMENT OF HUMAN HEALTH RISKS OF CHEMICALS IN THE NATURAL ENVIRONMENT

    Science.gov (United States)

    Balbus, John M; Boxall, Alistair BA; Fenske, Richard A; McKone, Thomas E; Zeise, Lauren

    2013-01-01

    Global climate change (GCC) is likely to alter the degree of human exposure to pollutants and the response of human populations to these exposures, meaning that risks of pollutants could change in the future. The present study, therefore, explores how GCC might affect the different steps in the pathway from a chemical source in the environment through to impacts on human health and evaluates the implications for existing risk-assessment and management practices. In certain parts of the world, GCC is predicted to increase the level of exposure of many environmental pollutants due to direct and indirect effects on the use patterns and transport and fate of chemicals. Changes in human behavior will also affect how humans come into contact with contaminated air, water, and food. Dietary changes, psychosocial stress, and coexposure to stressors such as high temperatures are likely to increase the vulnerability of humans to chemicals. These changes are likely to have significant implications for current practices for chemical assessment. Assumptions used in current exposure-assessment models may no longer apply, and existing monitoring methods may not be robust enough to detect adverse episodic changes in exposures. Organizations responsible for the assessment and management of health risks of chemicals therefore need to be more proactive and consider the implications of GCC for their procedures and processes. Environ. Toxicol. Chem. 2013;32:62–78. © 2012 SETAC PMID:23147420

  19. Implications of global climate change for the assessment and management of human health risks of chemicals in the natural environment.

    Science.gov (United States)

    Balbus, John M; Boxall, Alistair B A; Fenske, Richard A; McKone, Thomas E; Zeise, Lauren

    2013-01-01

    Global climate change (GCC) is likely to alter the degree of human exposure to pollutants and the response of human populations to these exposures, meaning that risks of pollutants could change in the future. The present study, therefore, explores how GCC might affect the different steps in the pathway from a chemical source in the environment through to impacts on human health and evaluates the implications for existing risk-assessment and management practices. In certain parts of the world, GCC is predicted to increase the level of exposure of many environmental pollutants due to direct and indirect effects on the use patterns and transport and fate of chemicals. Changes in human behavior will also affect how humans come into contact with contaminated air, water, and food. Dietary changes, psychosocial stress, and coexposure to stressors such as high temperatures are likely to increase the vulnerability of humans to chemicals. These changes are likely to have significant implications for current practices for chemical assessment. Assumptions used in current exposure-assessment models may no longer apply, and existing monitoring methods may not be robust enough to detect adverse episodic changes in exposures. Organizations responsible for the assessment and management of health risks of chemicals therefore need to be more proactive and consider the implications of GCC for their procedures and processes. Copyright © 2012 SETAC.

  20. Natural and pre-treatments induced variability in the chemical composition and morphology of lichens and mosses selected for active monitoring of airborne elements

    Energy Technology Data Exchange (ETDEWEB)

    Adamo, P. [Dipartimento di Scienze del Suolo, della Pianta, dell' Ambiente e delle Produzioni Animali, Universita di Napoli Federico II, Via Universita 100, I-80055 Portici (Italy)], E-mail: adamo@unina.it; Bargagli, R. [Dipartimento di Scienze Ambientali, Universita di Siena, Via P.A. Mattioli 4, I-53100 Siena (Italy); Giordano, S. [Dipartimento di Biologia Strutturale e Funzionale, Universita di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126 Naples (Italy); Modenesi, P. [DIP.TE.RIS, Universita di Genova, Corso Dogali 1/m, I-16136 Genova (Italy); Monaci, F. [Dipartimento di Scienze Ambientali, Universita di Siena, Via P.A. Mattioli 4, I-53100 Siena (Italy); Pittao, E. [Dipartimento di Biologia, Universita degli Studi di Trieste, Via L. Giorgieri 10, I-34127 Trieste (Italy); Spagnuolo, V. [Dipartimento di Biologia Strutturale e Funzionale, Universita di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126 Naples (Italy); Tretiach, M. [Dipartimento di Biologia, Universita degli Studi di Trieste, Via L. Giorgieri 10, I-34127 Trieste (Italy)

    2008-03-15

    To enhance the reliability of the moss and lichen transplant technique for active biomonitoring of trace metals in urban environments, we evaluated the natural variability in the chemical composition of the (epilithic and epiphytic) moss Hypnum cupressiforme and the epiphytic lichen Pseudevernia furfuracea from two reference areas in NE Italy. Green shoots of epilithic mosses and lobes of epiphytic lichens from larch branches showed rather homogenous composition and were selected for the exposure in nylon bags. As different physico-chemical pre-treatments are usually applied to selected cryptogamic material before its exposure, we also evaluated the effects of oven-drying at 120 deg. C for 24 h, washing in 1 N HNO{sub 3} solution, and in 0.5% NH{sub 4} oxalate solution at 85 deg. C for 15 h on the chemical composition and morphology of water-washed moss shoots and lichen lobes. Pre-treatments remarkably changed the chemical composition of selected materials but not their surface morphology. - Water-washed and oven-dried moss shoots and lichen lobes have adequate chemical and morphological homogeneity to be used as active biomonitors of trace element atmospheric deposition.

  1. Long-term correction of murine lipoprotein lipase deficiency with AAV1-mediated gene transfer of the naturally occurring LPL(S447X) beneficial mutation.

    Science.gov (United States)

    Ross, Colin J D; Twisk, Jaap; Meulenberg, Janneke M; Liu, Guoqing; van den Oever, Karin; Moraal, Ewoud; Hermens, Wim T; Rip, Jaap; Kastelein, John J P; Kuivenhoven, Jan Albert; Hayden, Michael R

    2004-09-01

    Human lipoprotein lipase (LPL) deficiency causes profound hypertriglyceridemia and life-threatening pancreatitis. We recently developed an adult murine model for LPL deficiency: LPL -/- mice display grossly elevated plasma triglyceride (TG) levels (>200-fold) and very low high-density lipoprotein cholesterol (HDL-C AAV1-LPL(S447X)) in muscle for the treatment of LPL deficiency. Intramuscular administration of AAV1-LPL(S447X) resulted in dose-dependent expression of hLPL protein and LPL activity (up to 33% of normal murine levels) in postheparin plasma. Remarkably, visible hyperlipidemia was resolved within 1 week; plasma TG was reduced to near-normal levels (from 99.0 to 1.8 mmol/L), and plasma HDL-C was increased 6-fold (from 0.2 to 1.1 mmol/L). At 8 months after administration of AAV1-LPL(S447X), an intravenous lipid challenge showed efficient, near-normal clearance of plasma TG. Histologic analyses of injected muscle further indicated that abnormal muscle morphology observed in LPL -/- mice was reversed after treatment. Expression of therapeutic levels of LPL(S447X), and the subsequent beneficial effect on plasma lipid levels, has lasted for more than 1 year. We therefore conclude that AAV1-mediated transfer of LPL(S447X) into murine skeletal muscle results in long-term near-correction of dyslipidemia associated with LPL deficiency.

  2. Mimicking natural cell environments: design, fabrication and application of bio-chemical gradients on polymeric biomaterial substrates

    NARCIS (Netherlands)

    Benetti, Edmondo Maria; Klein Gunnewiek, Michel; van Blitterswijk, Clemens; Vancso, Gyula J.; Moroni, Lorenzo

    2016-01-01

    Gradients of biomolecules on synthetic, solid substrates can efficiently mimic the natural, graded variation of properties of the extracellular matrix (ECM). Such gradients represent accessible study platforms for the understanding of cellular activities, and they also provide functional supports

  3. Using a Total Environment Framework (Built, Natural, Social Environments) to Assess Life-long Health Effects of Chemical Exposures

    Science.gov (United States)

    EPAseeks applications for research on how pollution affects human health in the context of the total environment – built, natural, and social environments interacting together with inherent characteristics and interactions.

  4. Technology diffusion of a different nature: Applications of nuclear safeguards technology to the chemical weapons verification regime

    Energy Technology Data Exchange (ETDEWEB)

    Kadner, S.P. [Aquila Technologies Group, Inc., Albuquerque, NM (United States); Reisman, A. [Brookhaven National Lab., Upton, NY (United States); Turpen, E. [Aquila Technologies Group, Inc., Cambridge, MA (United States)

    1996-10-01

    The following discussion focuses on the issue of arms control implementation from the standpoint of technology and technical assistance. Not only are the procedures and techniques for safeguarding nuclear materials undergoing substantial changes, but the implementation of the Chemical Weapons Convention (CWC) and the Biological Weapons Convention (BWC) will give rise to technical difficulties unprecedented in the implementation of arms control verification. Although these regimes present new challenges, an analysis of the similarities between the nuclear and chemical weapons non-proliferation verification regimes illustrates the overlap in technological solutions. Just as cost-effective and efficient technologies can solve the problems faced by the nuclear safeguards community, these same technologies offer solutions for the CWC safeguards regime. With this in mind, experts at the Organization for the Prohibition of Chemical Weapons (OPCW), who are responsible for verification implementation, need to devise a CWC verification protocol that considers the technology already available. The functional similarity of IAEA and the OPCW, in conjunction with the technical necessities of both verification regimes, should receive attention with respect to the establishment of a technical assistance program. Lastly, the advanced status of the nuclear and chemical regime vis-a-vis the biological non-proliferation regime can inform our approach to implementation of confidence building measures for biological weapons.

  5. Protein structure similarity clustering (PSSC) and natural product structure as inspiration sources for drug development and chemical genomics

    NARCIS (Netherlands)

    Dekker, Frank J; Koch, Marcus A; Waldmann, Herbert; Dekker, Frans

    Finding small molecules that modulate protein function is of primary importance in drug development and in the emerging field of chemical genomics. To facilitate the identification of such molecules, we developed a novel strategy making use of structural conservatism found in protein domain

  6. Revisiting the Chemistry Triplet: Drawing upon the Nature of Chemical Knowledge and the Psychology of Learning to Inform Chemistry Education

    Science.gov (United States)

    Taber, Keith S.

    2013-01-01

    Much scholarship in chemical education draws upon the model of there being three "levels" at which the teaching and learning of chemistry operates, a notion which is often represented graphically in terms of a triangle with the apices labelled as macroscopic, submicroscopic and symbolic. This model was proposed by Johnstone who argued that…

  7. Calculating correct compilers

    OpenAIRE

    Bahr, Patrick; Hutton, Graham

    2015-01-01

    In this article we present a new approach to the problem of calculating compilers. In particular, we develop a simple but general technique that allows us to derive correct compilers from high- level semantics by systematic calculation, with all details of the implementation of the compilers falling naturally out of the calculation process. Our approach is based upon the use of standard equational reasoning techniques, and has been applied to calculate compilers for a wide range of language f...

  8. Aerial Photography and Imagery, Ortho-Corrected, 1998 Fly Over - 6" Pixel Resolution - Natural Color - Tiff w/ World File - Nad83, Nevada State Plane, West Zone, US Foot - Broken up by Custom Grid, Published in 1998, City of Carson City Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Aerial Photography and Imagery, Ortho-Corrected dataset current as of 1998. 1998 Fly Over - 6" Pixel Resolution - Natural Color - Tiff w/ World File - Nad83, Nevada...

  9. Aerial Photography and Imagery, Ortho-Corrected, Digital orthophographs (DOPs) were derived from natural color aerial photographs taken in the spring of 2005. The DOP scale is 1:2400 (1" = 200') rectified to 12" pixels., Published in 2005, 1:2400 (1in=200ft) scale, Manitowoc County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Aerial Photography and Imagery, Ortho-Corrected dataset current as of 2005. Digital orthophographs (DOPs) were derived from natural color aerial photographs taken in...

  10. Chemically exfoliated Mo S2 layers: Spectroscopic evidence for the semiconducting nature of the dominant trigonal metastable phase

    Science.gov (United States)

    Pal, Banabir; Singh, Anjali; Sharada, G.; Mahale, Pratibha; Kumar, Abhinav; Thirupathaiah, S.; Sezen, H.; Amati, M.; Gregoratti, Luca; Waghmare, Umesh V.; Sarma, D. D.

    2017-11-01

    A metastable trigonal phase, existing only as small patches on a chemically exfoliated few-layered, thermodynamically stable 1 H phase of Mo S2 , is believed to critically influence the properties of Mo S2 -based devices. The electronic structure of this metastable phase is little understood in the absence of a direct experimental investigation of its electronic properties, complicated further by conflicting claims from theoretical investigations. We address this issue by investigating the electronic structure of this minority phase in chemically exfoliated Mo S2 few-layered systems by enhancing its contributions with the use of highly spatially resolved (≤120 nm resolution) photoemission spectroscopy and Raman spectroscopy in conjunction with state-of-the-art electronic structure calculations. Based on these results, we establish that the ground state of this phase, arrived at by the chemical exfoliation of Mo S2 using the usual Li intercalation technique, is a small gap (˜90 ±40 meV ) semiconductor in contrast to most claims in the literature; we also identify the specific trigonal structure it has among many suggested ones.

  11. TREATMENT OF HYDROCARBON, ORGANIC RESIDUE AND PRODUCTION CHEMICAL DAMAGE MECHANISMS THROUGH THE APPLICATION OF CARBON DIOXIDE IN NATURAL GAS STORAGE WELLS

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence J. Pekot

    2004-06-30

    Two gas storage fields were studied for this project. Overisel field, operated by Consumer's Energy, is located near the town of Holland, Michigan. Huntsman Storage Unit, operated by Kinder Morgan, is located in Cheyenne County, Nebraska near the town of Sidney. Wells in both fields experienced declining performance over several years of their annual injection/production cycle. In both fields, the presence of hydrocarbons, organic materials or production chemicals was suspected as the cause of progressive formation damage leading to the performance decline. Core specimens and several material samples were collected from these two natural gas storage reservoirs. Laboratory studies were performed to characterize the samples that were believed to be representative of a reservoir damage mechanism previously identified as arising from the presence of hydrocarbons, organic residues or production chemicals. A series of laboratory experiments were performed to identify the sample materials, use these materials to damage the flow capacity of the core specimens and then attempt to remove or reduce the induced damage using either carbon dioxide or a mixture of carbon dioxide and other chemicals. Results of the experiments showed that pure carbon dioxide was effective in restoring flow capacity to the core specimens in several different settings. However, in settings involving asphaltines as the damage mechanism, both pure carbon dioxide and mixtures of carbon dioxide and other chemicals provided little effectiveness in damage removal.

  12. Studies on the chemical resistance and mechanical properties of natural polyalthia cerasoides woven fabric/glass hybridized epoxy composites

    CSIR Research Space (South Africa)

    Jayaramudu, J

    2015-01-01

    Full Text Available In the present work, natural Polyalthiacerasoide woven fabrics were extracted from the bark of the tree and using these woven fabrics/glass fibre as reinforcements and epoxy as matrix the hybrid composites were prepared by the hand lay-up technique...

  13. To Avoid Chasing Incorrect Chemical Structures of Chiral Compounds: Raman Optical Activity and Vibrational Circular Dichroism Spectroscopies.

    Science.gov (United States)

    Polavarapu, Prasad L; Covington, Cody L; Raghavan, Vijay

    2017-09-20

    A chemical structure (CS) identifies the connectivities between atoms, and the nature of those connections, for a given elemental composition. For chiral molecules, in addition to the identification of CS, the identification of the correct absolute configuration (AC) is also needed. Several chiral natural products are known whose CSs were initially misidentified and later corrected, and these errors were often discovered during the total synthesis of natural products. In this work, we present a new and convenient approach that can be used with Raman optical activity (ROA) and vibrational circular dichroism (VCD) spectroscopies, to distinguish between the correct and incorrect CSs of chiral compounds. This approach involves analyzing the spectral similarity overlap between experimental spectra and those predicted with advanced quantum chemical theories. Significant labor needed for establishing the correct CSs via chemical syntheses of chiral natural products can thus be avoided. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Comparative molecular field analysis (CoMFA) model using a large diverse set of natural, synthetic and environmental chemicals for binding to the androgen receptor.

    Science.gov (United States)

    Hong, H; Fang, H; Xie, Q; Perkins, R; Sheehan, D M; Tong, W

    2003-01-01

    A large number of natural, synthetic and environmental chemicals are capable of disrupting the endocrine systems of experimental animals, wildlife and humans. These so-called endocrine disrupting chemicals (EDCs), some mimic the functions of the endogenous androgens, have become a concern to the public health. Androgens play an important role in many physiological processes, including the development and maintenance of male sexual characteristics. A common mechanism for androgen to produce both normal and adverse effects is binding to the androgen receptor (AR). In this study, we used Comparative Molecular Field Analysis (CoMFA), a three-dimensional quantitative structure-activity relationship (3D-QSAR) technique, to examine AR-ligand binding affinities. A CoMFA model with r2 = 0.902 and q2 = 0.571 was developed using a large training data set containing 146 structurally diverse natural, synthetic, and environmental chemicals with a 10(6)-fold range of relative binding affinity (RBA). By comparing the binding characteristics derived from the CoMFA contour map with these observed in a human AR crystal structure, we found that the steric and electrostatic properties encoded in this training data set are necessary and sufficient to describe the RBA of AR ligands. Finally, the CoMFA model was challenged with an external test data set; the predicted results were close to the actual values with average difference of 0.637 logRBA. This study demonstrates the utility of this CoMFA model for real-world use in predicting the AR binding affinities of structurally diverse chemicals over a wide RBA range.

  15. Theoretical derivation of flow laws for quartz dislocation creep: Comparisons with experimental creep data and extrapolation to natural conditions using water fugacity corrections

    Science.gov (United States)

    Fukuda, Jun-ichi; Shimizu, Ichiko

    2017-08-01

    We theoretically derived flow laws for quartz dislocation creep using climb-controlled dislocation creep models and compared them with available laboratory data for quartz plastic deformation. We assumed volume diffusion of oxygen-bearing species along different crystallographic axes (//c, ⊥R, and ⊥c) of α-quartz and β-quartz, and pipe diffusion of H2O, to be the elementary processes of dislocation climb. The relationships between differential stress (σ) and strain rate (ɛ>˙) are written as ɛ>˙∝σ3Dv and ɛ>˙∝σ5Dp for cases controlled by volume and pipe diffusion, respectively, where Dv and Dp are coefficients of diffusion for volume and pipe diffusion. In previous experimental work, there were up to 1.5 orders of magnitude difference in the water fugacity values in experiments that used either gas-pressure-medium or solid-pressure-medium deformation apparatus. Therefore, in both the theories and flow laws, we included water fugacity effects as modified preexponential factors and water fugacity terms. Previous experimental data were obtained mainly in the β-quartz field and are highly consistent with the volume-diffusion-controlled dislocation creep models of β-quartz involving the water fugacity term. The theory also predicts significant effects for the transition of α-β quartz under crustal conditions. Under experimental pressure and temperature conditions, the flow stress of pipe-diffusion-controlled dislocation creep is higher than that for volume-diffusion-controlled creep. Extrapolation of the flow laws to natural conditions indicates that the contributions of pipe diffusion may dominate over volume diffusion under low-temperature conditions of the middle crust around the brittle-plastic transition zone.

  16. Monitoring and physical-chemical modeling of conditions of natural surface and underground waters forming in the Kola North.

    Science.gov (United States)

    Mazukhina, Svetlana I; Masloboev, Vladimir A; Chudnenko, Konstantin V; Bychinsky, Valeriy A; Svetlov, Anton V; Muraviev, Sergey V

    2012-01-01

    Processes of surface and underground water forming in the Khibiny massif have been studied using a physical-chemical model of the "water-rock-atmosphere-organic substance" system. The obtained model solutions are indicative of the fact that formation of surface and underground water of the Khibiny massif takes place on the whole in the framework of the considered system without attracting a hypothetical outside source of pollutants. The results are of practical and methodological importance for assessment of prediction of the man-induced impact on water systems in conditions of Subarctic.

  17. Lessons from the past and charting the future of marine natural products drug discovery and chemical biology.

    Science.gov (United States)

    Gerwick, William H; Moore, Bradley S

    2012-01-27

    Marine life forms are an important source of structurally diverse and biologically active secondary metabolites, several of which have inspired the development of new classes of therapeutic agents. These success stories have had to overcome difficulties inherent to natural products-derived drugs, such as adequate sourcing of the agent and issues related to structural complexity. Nevertheless, several marine-derived agents are now approved, most as "first-in-class" drugs, with five of seven appearing in the past few years. Additionally, there is a rich pipeline of clinical and preclinical marine compounds to suggest their continued application in human medicine. Understanding of how these agents are biosynthetically assembled has accelerated in recent years, especially through interdisciplinary approaches, and innovative manipulations and re-engineering of some of these gene clusters are yielding novel agents of enhanced pharmaceutical properties compared with the natural product. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. On the chemical nature of boundary lubrication of stainless steel by chlorine - and sulfur-containing EP-additives

    DEFF Research Database (Denmark)

    Petrushina, Irina; Christensen, Erik; Bergqvist, Rene Stig

    2000-01-01

    The nature of the extreme pressure CEP) effect of the dialkylpolysulfides and chlorinated paraffins during the ironing of stainless steel AISI 304 has been studied. A strip reduction test was used in combination with differential thermal analysis (DTA), profilometry, X-ray photoelectron spectrosc......The nature of the extreme pressure CEP) effect of the dialkylpolysulfides and chlorinated paraffins during the ironing of stainless steel AISI 304 has been studied. A strip reduction test was used in combination with differential thermal analysis (DTA), profilometry, X-ray photoelectron...... steel strips were examined before and after strip reduction by use of AES sputter profiling. Results imply that the chlorine containing lubricant enforces the formation of a thick oxide layer. (C) 2000 Elsevier Science S.A. All rights reserved....

  19. Expanding the chemical diversity of natural esters by engineering a polyketide-derived pathway into Escherichia coli.

    Science.gov (United States)

    Menendez-Bravo, Simón; Comba, Santiago; Sabatini, Martín; Arabolaza, Ana; Gramajo, Hugo

    2014-07-01

    Microbial fatty acid (FA)-derived molecules have emerged as promising alternatives to petroleum-based chemicals for reducing dependence on fossil hydrocarbons. However, native FA biosynthetic pathways often yield limited structural diversity, and therefore restricted physicochemical properties, of the end products by providing only a limited variety of usually linear hydrocarbons. Here we have engineered into Escherichia coli a mycocerosic polyketide synthase-based biosynthetic pathway from Mycobacterium tuberculosis and redefined its biological role towards the production of multi-methyl-branched-esters (MBEs) with novel chemical structures. Expression of FadD28, Mas and PapA5 enzymes enabled the biosynthesis of multi-methyl-branched-FA and their further esterification to an alcohol. The high substrate tolerance of these enzymes towards different FA and alcohol moieties resulted in the biosynthesis of a broad range of MBE. Further metabolic engineering of the MBE producer strain coupled this system to long-chain-alcohol biosynthetic pathways resulting in de novo production of branched wax esters following addition of only propionate. Copyright © 2014 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  20. Chemical constituents of fine particulate air pollution and pulmonary function in healthy adults: The Healthy Volunteer Natural Relocation study

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shaowei; Deng, Furong; Hao, Yu [Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, Beijing (China); Shima, Masayuki [Department of Public Health, Hyogo College of Medicine, Hyogo (Japan); Wang, Xin; Zheng, Chanjuan; Wei, Hongying; Lv, Haibo; Lu, Xiuling; Huang, Jing; Qin, Yu [Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, Beijing (China); Guo, Xinbiao, E-mail: guoxb@bjmu.edu.cn [Department of Occupational and Environmental Health Sciences, Peking University School of Public Health, Beijing (China)

    2013-09-15

    Highlights: • Study subjects relocated between areas with different air pollution contents. • PM{sub 2.5} showed the most consistent inverse associations with pulmonary function. • Cu, Cd, As and Sn were consistently associated with reduced pulmonary function. • Carbonaceous fractions, SO{sub 4}{sup 2−} and Sb were also associated with pulmonary function. • Sources may include traffic, industry, coal burning, and long range transported dust. -- Abstract: The study examined the associations of 32 chemical constituents of particulate matter with an aerodynamic diameter ≤2.5 μm (PM{sub 2.5}) with pulmonary function in a panel of 21 college students. Study subjects relocated from a suburban area to an urban area with changing ambient air pollution levels and contents in Beijing, China, and provided daily morning/evening peak expiratory flow (PEF) and forced expiratory volume in 1 s (FEV{sub 1}) measurements over 6 months in three study periods. There were significant reductions in evening PEF and morning/evening FEV{sub 1} associated with various air pollutants and PM{sub 2.5} constituents. Four PM{sub 2.5} constituents (copper, cadmium, arsenic and stannum) were found to be most consistently associated with the reductions in these pulmonary function measures. These findings provide clues for the respiratory effects of specific particulate chemical constituents in the context of urban air pollution.

  1. Diallyl disulphide as natural organosulphur friction modifier via the in-situ tribo-chemical formation of tungsten disulphide

    Science.gov (United States)

    Rodríguez Ripoll, Manel; Totolin, Vladimir; Gabler, Christoph; Bernardi, Johannes; Minami, Ichiro

    2018-01-01

    The present work shows a novel method for generating in-situ low friction tribofilms containing tungsten disulphide in lubricated contacts using diallyl disulphide as sulphur precursor. The approach relies on the tribo-chemical interaction between the diallyl disulphide and a surface containing embedded sub-micrometer tungsten carbide particles. The results show that upon sliding contact between diallyl disulphide and the tungsten-containing surface, the coefficient of friction drops to values below 0.05 after an induction period. The reason for the reduction in friction is due to tribo-chemical reactions that leads to the in-situ formation of a complex tribofilm that contains iron and tungsten components. X-ray photoelectron spectroscopy analyses indicate the presence of tungsten disulphide at the contact interface, thus justifying the low coefficient of friction achieved during the sliding experiments. It was proven that the low friction tribofilms can only be formed by the coexistence of tungsten and sulphur species, thus highlighting the synergy between diallyl disulphide and the tungsten-containing surface. The concept of functionalizing surfaces to react with specific additives opens up a wide range of possibilities, which allows tuning on-site surfaces to target additive interactions.

  2. Chemical and Biological Aspects of the Natural 1,4-Benzoquinone Embelin and its (semi-)Synthetic Derivatives.

    Science.gov (United States)

    Shuveksh, Priti Singh; Ahmed, Khursheed; Padhye, Subhash; Schobert, Rainer; Biersack, Bernhard

    2017-01-01

    Like the impressive biological properties of embelin, its chemical aspects have raised the interest of scientists in the field as well. A detailed understanding of the chemistry of embelin is necessary to fully exploit it medicinally. Search for embelin isolation and its chemical modifications was carried out using web-based literature searching tools such as Pubmed and Scifinder. Pertinent literature is covered up to 2016. Structures of bioactive embelin derivatives are provided. Pure embelin, obtained from Embelia ribes berries extraction or by total synthesis, was applied for a number of biological assays. Semi-synthetic and total synthetic approaches led to new high affinity embelin-derived inhibitors of crucial protein targets and to new embelin derivatives with improved pharmacological properties (e.g., with better water-solubility or as applications for drug carrier systems). This review provides a summary of the rich chemistry of embelin and the latest developments in the field of optimized (semi-)synthetic embelin derivatives including their biological activities. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Chemical constituents of fine particulate air pollution and pulmonary function in healthy adults: the Healthy Volunteer Natural Relocation study.

    Science.gov (United States)

    Wu, Shaowei; Deng, Furong; Hao, Yu; Shima, Masayuki; Wang, Xin; Zheng, Chanjuan; Wei, Hongying; Lv, Haibo; Lu, Xiuling; Huang, Jing; Qin, Yu; Guo, Xinbiao

    2013-09-15

    The study examined the associations of 32 chemical constituents of particulate matter with an aerodynamic diameter ≤2.5 μm (PM₂.₅) with pulmonary function in a panel of 21 college students. Study subjects relocated from a suburban area to an urban area with changing ambient air pollution levels and contents in Beijing, China, and provided daily morning/evening peak expiratory flow (PEF) and forced expiratory volume in 1s (FEV₂₁) measurements over 6 months in three study periods. There were significant reductions in evening PEF and morning/evening FEV₂₁ associated with various air pollutants and PM₂.₅ constituents. Four PM₂.₅ constituents (copper, cadmium, arsenic and stannum) were found to be most consistently associated with the reductions in these pulmonary function measures. These findings provide clues for the respiratory effects of specific particulate chemical constituents in the context of urban air pollution. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Effect of the natural winemaking process applied at industrial level on the microbiological and chemical characteristics of wine.

    Science.gov (United States)

    Sannino, Ciro; Francesca, Nicola; Corona, Onofrio; Settanni, Luca; Cruciata, Margherita; Moschetti, Giancarlo

    2013-09-01

    The composition of yeast and lactic acid bacteria (LAB) communities and the chemical evolution of the large-scale commercial vinification of Catarratto IGT Sicilia, carried out under the biological regime, was followed from grape harvest until bottling. Simultaneously to the maximum growth of yeasts, LAB counts reached high level of concentration (6-7 log CFU mL(-1)) during the first steps of the alcoholic fermentation. Yeast identification was determined applying different molecular methods. The highest species biodiversity was observed on grape and must samples taken soon after pressing. Saccharomyces cerevisiae was detected at dominant concentrations during the entire winemaking process. LAB cultures were grouped and identified by a combined phenotypic and genotypic approach. Leuconostoc mesenteroides, Lactobacillus hilgardii and Lactobacillus plantarum species were identified; the last was the main LAB recognized during vinification. The winemaking process was also chemically monitored. The alcoholic content was approximately 12.67% (v v(-1)) at bottling; pH, volatile acidity and total acidity showed a moderate increase during vinification. Tartaric, citric and malic acids decreased until bottling, while lactic acid showed a rapid increase at the end of maceration and bottling. Trans-caffeil tartaric acid was the most abundant phenolic compound and volatile organic compounds (VOC) were mainly represented by isoamylic alcohol, isobutanol, ethyl acetate and octanoic acid. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  5. Lessons from the Past and Charting the Future of Marine Natural Products Drug Discovery and Chemical Biology

    OpenAIRE

    Gerwick, William H.; Moore, Bradley S.

    2012-01-01

    Marine life forms are an important source of structurally-diverse and biologically-active secondary metabolites, several of which have inspired the development of new classes of therapeutic agents. These success stories have had to overcome difficulties inherent to natural products-derived drugs, such as adequate sourcing of the agent and issues related to structural complexity. Nevertheless, several marine-derived agents are now approved, most as `first-in-class' drugs, with 5 of 7 appearing...

  6. Physical Nature of the Processes in Structure Forming, Phase and Chemical Composition of pipe Permanent Joints when MMA Welding

    Science.gov (United States)

    Il'yaschenko, D. P.; Chinakhov, D. A.; Danilov, V. I.; Sadykov, I. D.

    2016-04-01

    The paper outlines peculiarities of structure formation, phase and chemical composition in regard to heat content in molten electrode metal beads when pipe steel (steel 09G2S) welding using power sources with various energy characteristics. Mathematical calculations indicate an inverter power source provides minor heat content into the bead of electrode metal when welding. Experimental research has pointed at 4-9 % increase in impact strength of joints produced using an inverter power source in comparison with samples produced applying a diode rectifier. The following factors can possibly give rise to the increasing impact strength: difference in microstructures of weld joints, up to 50% shortening ferritic plates in metal of weld joint, change in dimensions of ferritic grains in the heat-affected zone by as much as 17.5 %, and decrease in the extent of heat-affected zone by 50%.

  7. Operation of the NETL Chemical Looping Reactor with Natural Gas and a Novel Copper-Iron Material

    Energy Technology Data Exchange (ETDEWEB)

    Bayham, Sanuel [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Straub, Doug [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Weber, Justin [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    2017-02-01

    As part of the U.S. Department of Energy’s Advanced Combustion Program, the National Energy Technology Laboratory’s Research and Innovation Center (NETL R&IC) is investigating the feasibility of a novel combustion concept in which the GHG emissions can be significantly reduced. This concept involves burning fuel and air without mixing these two reactants. If this concept is technically feasible, then CO2 emissions can be significantly reduced at a much lower cost than more conventional approaches. This indirect combustion concept has been called Chemical Looping Combustion (CLC) because an intermediate material (i.e., a metaloxide) is continuously cycled to oxidize the fuel. This CLC concept is the focus of this research and will be described in more detail in the following sections.

  8. Interactions among chemical components of Cocoa tea (Camellia ptilophylla Chang), a naturally low caffeine-containing tea species.

    Science.gov (United States)

    Lin, Xiaorong; Chen, Zhongzheng; Zhang, Yuanyuan; Gao, Xiong; Luo, Wei; Li, Bin

    2014-06-01

    In the 1980s, a novel tea species, Cocoa tea (Camellia ptilophylla Chang), was discovered in Southern China with surprisingly low caffeine content (0.2% by dry weight). Although its health promoting characteristics have been known for a while, a very limited amount of scientific research has been focused on Cocoa tea. Herein, a systematic study on Cocoa tea and its chemical components, interactions and bioactivities was performed. YD tea (Yunnan Daye tea, Camellia sinensis), a tea species with a high caffeine content (5.8% by dry weight), was used as a control. By UV-Vis spectrometry, High Performance Liquid Chromatography (HPLC), and Flame Atomic Absorption Spectrometry (FAAS) for chemical composition analysis, C-2 epimeric isomers of tea catechins and theobromine were found to be the major catechins and methylxanthine in Cocoa tea, respectively. More gallated catechins, methylxanthines, and proteins were detected in Cocoa tea compared with YD tea. Moreover, the tendency of major components in Cocoa tea for precipitation was significantly higher than that in YD tea. Catechins, methylxanthines, proteins, iron, calcium, and copper were presumed to be the origins of molecular interactions in Cocoa tea and YD tea. The interactions between catechins and methylxanthines were highly related to the galloyl moiety in catechins and methyl groups in methylxanthines. In vitro anti-inflammatory activity assays revealed that Cocoa tea was a more potent inhibitor of nitric oxide (NO) in lipopolysaccharide (LPS)-stimulated macrophage cells (RAW 264.7) than YD tea. This study constructs a solid phytochemical foundation for further research on the mechanisms of molecular interactions and the integrated functions of Cocoa tea.

  9. Blood pressure changes and chemical constituents of particulate air pollution: results from the healthy volunteer natural relocation (HVNR) study.

    Science.gov (United States)

    Wu, Shaowei; Deng, Furong; Huang, Jing; Wang, Hongyi; Shima, Masayuki; Wang, Xin; Qin, Yu; Zheng, Chanjuan; Wei, Hongying; Hao, Yu; Lv, Haibo; Lu, Xiuling; Guo, Xinbiao

    2013-01-01

    Elevated blood pressure (BP) has been associated with particulate matter (PM) air pollution, but associations with PM chemical constituents are still uncertain. We investigated associations of BP with various chemical constituents of fine PM (PM2.5) during 460 repeated visits among a panel of 39 university students. Resting BP was measured using standardized methods before and after the university students relocated from a suburban campus to an urban campus with different air pollution contents in Beijing, China. Air pollution data were obtained from central monitors close to student residences. We used mixed-effects models to estimate associations of various PM2.5 constituents with systolic BP (SBP), diastolic BP (DBP), and pulse pressure. An interquartile range increase of 51.2 μg/m3 in PM2.5 was associated with a 1.08-mmHg (95% CI: 0.17, 1.99) increase in SBP and a 0.96-mmHg (95% CI: 0.31, 1.61) increase in DBP on the following day. A subset of PM2.5 constituents, including carbonaceous fractions (organic carbon and elemental carbon), ions (chloride and fluoride), and metals/metalloid elements (nickel, zinc, magnesium, lead, and arsenic), were found to have robust positive associations with different BP variables, though robust negative associations of manganese, chromium, and molybdenum with SBP or DBP also were observed. Our results support relationships between specific PM2.5 constituents and BP. These findings have potential implications for the development of pollution abatement strategies that maximize public health benefits.

  10. Sequential chemical treatment of radium species in TENORM waste sludge produced from oil and natural gas production.

    Science.gov (United States)

    El Afifi, E M; Awwad, N S; Hilal, M A

    2009-01-30

    This paper is dedicated to the treatment of sludge occurring in frame of the Egyptian produced from oil and gas production. The activity levels of three radium isotopes: Ra-226 (of U-series), Ra-228 and Ra-224 (of Th-series) in the solid TENORM waste (sludge) were first evaluated and followed by a sequential treatment for all radium species (fractions) presented in TENORM. The sequential treatment was carried out based on two approaches 'A' and 'B' using different chemical solutions. The results obtained indicate that the activity levels of all radium isotopes (Ra-226, Ra-228 and Ra-224) of the environmental interest in the TENORM waste sludge were elevated with regard to exemption levels established by IAEA [International Atomic Energy Agency (IAEA), International basic safety standards for the protection against ionizing radiation and for the safety of radiation sources. GOV/2715/Vienna, 1994]. Each approach of the sequential treatment was performed through four steps using different chemical solutions to reduce the activity concentration of radium in a large extent. Most of the leached radium was found as an oxidizable Ra species. The actual removal % leached using approach B was relatively efficient compared to A. It is observed that the actual removal percentages (%) of Ra-226, Ra-228 and Ra-224 using approach A are 78+/-2.8, 64.8+/-4.1 and 76.4+/-5.2%, respectively. Whereas in approach A, the overall removal % of Ra-226, Ra-228 and Ra-228 was increased to approximately 91+/-3.5, 87+/-4.1 and 90+/-6.2%, respectively.

  11. A rapid and high-precision method for sulfur isotope δ(34)S determination with a multiple-collector inductively coupled plasma mass spectrometer: matrix effect correction and applications for water samples without chemical purification.

    Science.gov (United States)

    Lin, An-Jun; Yang, Tao; Jiang, Shao-Yong

    2014-04-15

    Previous studies have indicated that prior chemical purification of samples, although complex and time-consuming, is essential in obtaining precise and accurate results for sulfur isotope ratios using multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). In this study, we introduce a new, rapid and precise MC-ICP-MS method for sulfur isotope determination from water samples without chemical purification. The analytical work was performed on an MC-ICP-MS instrument with medium mass resolution (m/Δm ~ 3000). Standard-sample bracketing (SSB) was used to correct samples throughout the analytical sessions. Reference materials included an Alfa-S (ammonium sulfate) standard solution, ammonium sulfate provided by the lab of the authors and fresh seawater from the South China Sea. A range of matrix-matched Alfa-S standard solutions and ammonium sulfate solutions was used to investigate the matrix (salinity) effect (matrix was added in the form of NaCl). A seawater sample was used to confirm the reliability of the method. Using matrix-matched (salinity-matched) Alfa-S as the working standard, the measured δ(34)S value of AS (-6.73 ± 0.09‰) was consistent with the reference value (-6.78 ± 0.07‰) within the uncertainty, suggesting that this method could be recommended for the measurement of water samples without prior chemical purification. The δ(34)S value determination for the unpurified seawater also yielded excellent results (21.03 ± 0.18‰) that are consistent with the reference value (20.99‰), thus confirming the feasibility of the technique. The data and the results indicate that it is feasible to use MC-ICP-MS and matrix-matched working standards to measure the sulfur isotopic compositions of water samples directly without chemical purification. In comparison with the existing MC-ICP-MS techniques, the new method is better for directly measuring δ(34)S values in water samples with complex matrices; therefore, it can

  12. The electronic nature of the 1,4-β-glycosidic bond and its chemical environment: DFT insights into cellulose chemistry.

    Science.gov (United States)

    Loerbroks, Claudia; Rinaldi, Roberto; Thiel, Walter

    2013-11-25

    The molecular understanding of the chemistry of 1,4-β-glucans is essential for designing new approaches to the conversion of cellulose into platform chemicals and biofuels. In this endeavor, much attention has been paid to the role of hydrogen bonding occurring in the cellulose structure. So far, however, there has been little discussion about the implications of the electronic nature of the 1,4-β-glycosidic bond and its chemical environment for the activation of 1,4-β-glucans toward acid-catalyzed hydrolysis. This report sheds light on these central issues and addresses their influence on the acid hydrolysis of cellobiose and, by analogy, cellulose. The electronic structure of cellobiose was explored by DFT at the BB1 K/6-31++G(d,p) level. Natural bond orbital (NBO) analysis was performed to grasp the key bonding concepts. Conformations, protonation sites, and hydrolysis mechanisms were examined. The results for cellobiose indicate that cellulose is protected against hydrolysis not only by its supramolecular structure, as currently accepted, but also by its electronic structure, in which the anomeric effect plays a key role. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Non-disturbing characterization of natural organic matter (NOM) contained in clay rock pore water by mass spectrometry using electrospray and atmospheric pressure chemical ionization modes.

    Science.gov (United States)

    Huclier-Markai, Sandrine; Landesman, Catherine; Rogniaux, Hélène; Monteau, Fabrice; Vinsot, Agnes; Grambow, Bernd

    2010-01-01

    We have investigated the composition of the mobile natural organic matter (NOM) present in Callovo-Oxfodian pore water using electrospray ionization mass spectrometry (ESI-MS), atmospheric pressure chemical ionization mass spectrometry (APCI-MS) and emission-excitation matrix (EEM) spectroscopy. The generation of knowledge of the composition, structure and size of mobile NOM is necessary if one wants to understand the interactions of these compounds with heavy metals/radionuclides, in the context of environmental studies, and particularly how the mobility of these trace elements is affected by mobile NOM. The proposed methodology is very sensitive in unambiguously identifying the in situ composition of dissolved NOM in water even at very low NOM concentration, due to innovative non-disturbing water sampling and ionization (ESI/APCI-MS) techniques. It was possible to analyze a quite exhaustive inventory of the small organic compounds of clay pore water without proceeding to any chemical treatment at naturally occurring concentration levels. The structural features observed were mainly acidic compounds and fatty acids as well as aldehydes and amino acids. Copyright 2009 John Wiley & Sons, Ltd.

  14. Evolution of Chemical Diversity in a Group of Non-Reduced Polyketide Gene Clusters: Using Phylogenetics to Inform the Search for Novel Fungal Natural Products

    Directory of Open Access Journals (Sweden)

    Kurt Throckmorton

    2015-09-01

    Full Text Available Fungal polyketides are a diverse class of natural products, or secondary metabolites (SMs, with a wide range of bioactivities often associated with toxicity. Here, we focus on a group of non-reducing polyketide synthases (NR-PKSs in the fungal phylum Ascomycota that lack a thioesterase domain for product release, group V. Although widespread in ascomycete taxa, this group of NR-PKSs is notably absent in the mycotoxigenic genus Fusarium and, surprisingly, found in genera not known for their secondary metabolite production (e.g., the mycorrhizal genus Oidiodendron, the powdery mildew genus Blumeria, and the causative agent of white-nose syndrome in bats, Pseudogymnoascus destructans. This group of NR-PKSs, in association with the other enzymes encoded by their gene clusters, produces a variety of different chemical classes including naphthacenediones, anthraquinones, benzophenones, grisandienes, and diphenyl ethers. We discuss the modification of and transitions between these chemical classes, the requisite enzymes, and the evolution of the SM gene clusters that encode them. Integrating this information, we predict the likely products of related but uncharacterized SM clusters, and we speculate upon the utility of these classes of SMs as virulence factors or chemical defenses to various plant, animal, and insect pathogens, as well as mutualistic fungi.

  15. Influence of the natural Rio Negro water on the toxicological effects of a crude oil and its chemical dispersion to the Amazonian fish Colossoma macropomum.

    Science.gov (United States)

    Sadauskas-Henrique, Helen; Braz-Mota, Susana; Duarte, Rafael Mendonça; de Almeida-Val, Vera Maria Fonseca

    2016-10-01

    The increment in crude oil exploitation over the last decades has considerably increased the risk of polycyclic aromatic hydrocarbon (PAH) contamination to Amazonian aquatic environments, especially for the black water environments such as the Rio Negro. The present work was designed to evaluate the acute toxicity of the Urucu crude oil (CO), the chemically dispersed Urucu crude oil (CO + D), and the dispersant alone (D) to the Amazonian fish Colossoma macropomum. Acute toxicity tests were performed, using a more realistic approach, where fish were acclimated to both groundwater (GW), used as internal control, and natural Rio Negro water (RNW) and exposed to CO, CO + D and D. Then, biomarkers such as ethoxyresorufin-O-deethylase (EROD), superoxide dismutase (SOD), lipid peroxidation (LPO), serum sorbitol dehydrogenase (s-SDH) in liver, DNA damage in blood cells, and the presence of the benzo[a]pyrene-type, pyrene-type, and naphthalene-type metabolites in fish bile were assessed. Fish exposed to CO and CO + D, at both water types tested, presented increased biomarker responses and higher PAH-type metabolites in the bile. However, fish exposed to these treatments after the acclimation to RNW increased the levels of LPO, s-SDH (hepatotoxicity), DNA damage in blood cells (genotoxicity), and benzo[a]pyrene-type metabolites when compared to fish in GW. Our data suggests that some physicochemical properties of Rio Negro water (i.e., presence of natural organic matter (NOM)) might cause mild chemical stress responses in fish, which can make it more susceptible to oxidative stress following exposure to crude oil, particularly to those chemically dispersed.

  16. Operation of the NETL Chemical Looping Reactor with Natural Gas and a Novel Copper-Iron Material

    Energy Technology Data Exchange (ETDEWEB)

    Straub, Douglas [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Bayham, Samuel [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Weber, Justin [National Energy Technology Lab. (NETL), Morgantown, WV (United States)

    2017-02-21

    The proposed Clean Power Plan requires CO2 emission reductions of 30% by 2030 and further reductions are targeted by 2050. The current strategies to achieve the 30% reduction targets do not include options for coal. However, the 2016 Annual Energy Outlook suggests that coal will continue to provide more electricity than renewable sources for many regions of the country in 2035. Therefore, cost effective options to reduce greenhouse gas emissions from fossil fuel power plants are vital in order to achieve greenhouse gas reduction targets beyond 2030. As part of the U.S. Department of Energy’s Advanced Combustion Program, the National Energy Technology Laboratory’s Research and Innovation Center (NETL R&IC) is investigating the feasibility of a novel combustion concept in which the GHG emissions can be significantly reduced. This concept involves burning fuel and air without mixing these two reactants. If this concept is technically feasible, then CO2 emissions can be significantly reduced at a much lower cost than more conventional approaches. This indirect combustion concept has been called Chemical Looping Combustion (CLC) because an intermediate material (i.e., a metal-oxide) is continuously cycled to oxidize the fuel. This CLC concept is the focus of this research and will be described in more detail in the following sections. The solid material that is used to transport oxygen is called an oxygen carrier material. The cost, durability, and performance of this material is a key issue for the CLC technology. Researchers at the NETL R&IC have developed an oxygen carrier material that consists of copper, iron, and alumina. This material has been tested extensively using lab scale instruments such as thermogravimetric analysis (TGA), scanning electron microscopy (SEM), mechanical attrition (ASTM D5757), and small fluidized bed reactor tests. This report will describe the results from a realistic, circulating, proof-of-concept test that was

  17. Chemical and biological explorations of the electrophilic reactivity of the bioactive marine natural product halenaquinone with biomimetic nucleophiles.

    Science.gov (United States)

    Wang, Jiayi; Bourguet-Kondracki, Marie-Lise; Longeon, Arlette; Dubois, Joëlle; Valentin, Alexis; Copp, Brent R

    2011-02-15

    The electrophilic reactivity of the bioactive marine sponge natural product halenaquinone has been investigated by reaction with the biomimetic nucleophiles N-acetyl-L-cysteine and N(α)-acetyl-L-lysine. While cysteine reacted at the vacant quinone positions C-14 and C-15, lysine was found to react preferentially at the keto-furan position C-1. A small library of analogues was prepared by reaction of halenaquinone with primary amines, and evaluated against a range of biological targets including phospholipase A(2), farnesyltransferases (FTases) and Plasmodium falciparum. Geranylamine analogue 11 exhibited the most potent activity towards FTases (IC(50) 0.017-0.031 μM) and malaria (IC(50) 0.53-0.62 μM). Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. The Effects of Environmental Exposure on the Optical, Physical, and Chemical Properties of Manufactured Fibers of Natural Origin.

    Science.gov (United States)

    Brinsko, Kelly M; Sparenga, Sebastian; King, Meggan

    2016-09-01

    Manufactured fibers derived from natural origins include viscose rayon, azlon, and polylactic acid (PLA). A 2-year study was conducted to document any changes these fibers undergo as a result of exposure to various environmental conditions. Fabric swatches representing each fiber type were exposed to freshwater, saltwater, heat, cold, ultraviolet light, or composter conditions. Fibers from the swatches were periodically analyzed using polarized light microscopy and Fourier transform infrared microspectroscopy. Fiber solubility and melting-point behavior were measured every 6 months. Except for the complete degradation of viscose rayon in the composter, saltwater, and freshwater environs, no changes in the optical properties, infrared spectra, solubility, or melting points of the remaining fibers in any of the environments were observed. However, microscopic morphological changes were observed in fibers from two azlon swatches submerged in freshwater and saltwater, two PLA swatches exposed to ultraviolet light, and two viscose rayon swatches exposed to ultraviolet light. © 2016 American Academy of Forensic Sciences.

  19. From DNA Sequences to Chemical Structures – Methods for Mining Microbial Genomic and Metagenomic Data Sets for New Natural Products

    Directory of Open Access Journals (Sweden)

    Jurica Zucko

    2010-01-01

    Full Text Available Rapid mining of large genomic and metagenomic data sets for modular polyketide synthases, non-ribosomal peptide synthetases and hybrid polyketide synthase/non-ribosomal peptide synthetase biosynthetic gene clusters has been achieved using the generic computer program packages ClustScan and CompGen. These program packages perform the annotation with the hierarchical structuring into polypeptides, modules and domains, as well as storage and graphical presentations of the data. This aims to achieve the most accurate predictions of the activities and specificities of catalytically active domains that can be made with present knowledge, leading to a prediction of the most likely chemical structures produced by these enzymes. The program packages also allow generation of novel clusters by homologous recombination of the annotated genes in silico. ClustScan and CompGen were used to construct a custom database of known compounds (CSDB and of predicted entirely novel recombinant products (r-CSDB that can be used for in silico screening with computer aided drug design technology. The use of these programs has been exemplified by analysing genomic sequences from terrestrial prokaryotes and eukaryotic microorganisms, a marine metagenomic data set and a newly discovered example of a 'shared metabolic pathway' in marine-microbial endosymbiosis.

  20. Smooth perfluorinated surfaces with different chemical and physical natures: their unusual dynamic dewetting behavior toward polar and nonpolar liquids.

    Science.gov (United States)

    Cheng, Dalton F; Masheder, Benjamin; Urata, Chihiro; Hozumi, Atsushi

    2013-09-10

    The effects of surface chemistry and the mobility of surface-tethered functional groups of various perfluorinated surfaces on their dewetting behavior toward polar (water) and nonpolar (n-hexadecane, n-dodecane, and n-decane) liquids were investigated. In this study, three types of common smooth perfluorinated surfaces, that is, a perfluoroalkylsilane (heptadecafluoro-1,1,2,2-tetrahydrooctyl-dimethylchlorosilane, FAS17) monomeric layer, an amorphous fluoropolymer film (Teflon AF 1600), and a perfluorinated polyether (PFPE)-terminated polymer brush film (Optool DSX), were prepared and their static/dynamic dewetting characteristics were compared. Although the apparent static contact angles (CAs) of these surfaces with all probe liquids were almost identical to each other, the ease of movement of liquid drops critically depended on the physical (solidlike or liquidlike) natures of the substrate surface. CA hysteresis and substrate tilt angles (TAs) of all probe liquids on the Optool DSX surface were found to be much lower than those of Teflon AF1600 and FAS17 surfaces due to its physical polymer chain mobility at room temperature and the resulting liquidlike nature. Only 6.0° of substrate incline was required to initiate movement for a small drop (5 μL) of n-decane, which was comparable to the reported substrate TA value (5.3°) for a superoleophobic surface (θ(S) > 160°, textured perfluorinated surface). Such unusual dynamic dewetting behavior of the Optool DSX surface was also markedly enhanced due to the significant increase in the chain mobility of PFPE by moderate heating (70 °C) of the surface, with substrate TA reducing to 3.0°. CA hysteresis and substrate TAs rather than static CAs were therefore determined to be of greater consequence for the estimation of the actual dynamic dewetting behavior of alkane probe liquids on these smooth perfluorinated surfaces. Their dynamic dewettability toward alkane liquids is in the order of Optool DSX > Teflon AF1600

  1. Glycosyltransferase cascades made fit for chemical production: Integrated biocatalytic process for the natural polyphenol C-glucoside nothofagin.

    Science.gov (United States)

    Schmölzer, Katharina; Lemmerer, Martin; Nidetzky, Bernd

    2018-03-01

    Glycosyltransferase cascades are promising tools of biocatalysis for natural product glycosylation, but their suitability for actual production remains to be shown. Here, we demonstrate at a scale of 100 g isolated product the integrated biocatalytic production of nothofagin, the natural 3'-C-β-D-glucoside of the polyphenol phloretin. A parallel reaction cascade involving coupled C-glucosyltransferase and sucrose synthase was optimized for the one-pot glucosylation of phloretin from sucrose via an UDP/UDP-glucose shuttle. Inclusion complexation with the highly water soluble 2-hydroxypropyl-β-cyclodextrin pushed the phloretin solubility to its upper practical limit (∼120 mM) and so removed the main bottleneck on an efficient synthesis of nothofagin. The biotransformation thus intensified had excellent performance metrics of 97% yield and ∼50 gproduct /L at a space-time yield of 3 g/L/hr. The UDP-glucose was regenerated up to ∼220 times. A scalable downstream process for efficient recovery of nothofagin (≥95% purity; ≥65% yield) was developed. A tailored anion-exchange chromatography at pH 8.5 was used for capture and initial purification of the product. Recycling of the 2-hydroxypropyl-β-cyclodextrin would also be possible at this step. Product precipitation at a lowered pH of 6.0 and re-dissolution in acetone effectively replaced desalting by size exclusion chromatography in the final step of nothofagin purification. This study therefore, reveals the potential for process intensification in the glycosylation of polyphenol acceptors by glycosyltransferase cascades. It demonstrates that, with up- and downstream processing carefully optimized and suitably interconnected, a powerful biocatalytic technology becomes available for the production of an important class of glycosides difficult to prepare otherwise. © 2017 Wiley Periodicals, Inc.

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

    Directory of Open Access Journals (Sweden)

    Enrique Arévalo-Gardini

    Full Text Available 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.

  3. 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.

  4. Selecting the best AOP for isoxazolyl penicillins degradation as a function of water characteristics: Effects of pH, chemical nature of additives and pollutant concentration.

    Science.gov (United States)

    Villegas-Guzman, Paola; Silva-Agredo, Javier; Florez, Oscar; Giraldo-Aguirre, Ana L; Pulgarin, Cesar; Torres-Palma, Ricardo A

    2017-04-01

    To provide new insights toward the selection of the most suitable AOP for isoxazolyl penicillins elimination, the degradation of dicloxacillin, a isoxazolyl penicillin model, was studied using different advanced oxidation processes (AOPs): ultrasound (US), photo-Fenton (UV/H2O2/Fe2+) and TiO2 photocatalysis (UV/TiO2). Although all processes achieved total removal of the antibiotic and antimicrobial activity, and increased the biodegradability level of the solutions, significant differences concerning the mineralization extend, the pH of the solution, the pollutant concentration and the chemical nature of additives were found. UV/TiO2 reached almost complete mineralization; while ∼10% mineralization was obtained for UV/H2O2/Fe2+ and practically zero for US. Effect of initial pH, mineral natural water and the presence of organic (glucose, 2-propanol and oxalic acid) were then investigated. UV/H2O2/Fe2+ and US processes were improved in acidic media, while natural pH favored UV/TiO2 system. According to both the nature of the added organic compound and the process, inhibition, no effect or enhancement of the degradation rate was observed. The degradation in natural mineral water showed contrasting results according to the antibiotic concentration: US process was enhanced at low concentration of dicloxacillin followed by detrimental effects at high substrate concentrations. A contrary effect was observed during photo-Fenton, while UV/TiO2 was inhibited in all of cases. Finally, a schema illustrating the enhancement or inhibiting effects of water matrix is proposed as a tool for selecting the best process for isoxazolyl penicillins degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Differential effects of natural palm oil, chemically- and enzymatically-modified palm oil on weight gain, blood lipid metabolites and fat deposition in a pediatric pig model.

    Science.gov (United States)

    Ponnampalam, Eric N; Lewandowski, Paul; Nesaratnam, Kalanithi; Dunshea, Frank R; Gill, Harsharn

    2011-05-18

    Increasing prevalence of obesity and overweight in the Western world, continue to be a major health threat and is responsible for increased health care costs. Dietary intervention studies show a strong positive association between saturated fat intake and the development of obesity and cardiovascular disease. This study investigated the effect of positional distribution of palmitic acid (Sn-1, 2 & 3) of palm oil on cardiovascular health and development of obesity, using weaner pigs as a model for young children. Male and female weaner piglets were randomly allocated to 4 dietary treatment groups: 1) pork lard (LRD); 2) natural palm olein (NPO); 3) chemically inter-esterified PO (CPO) and 4) enzymatically inter-esterified PO (EnPO) as the fat source. Diets were formulated with 11% lard or with palm olein in order to provide 31% of digestible energy from fat in the diet and were balanced for cholesterol, protein and energy across treatments. From 8 weeks onwards, pigs on EnPO diet gained (Pweight than all other groups. Feed conversion efficiency (feed to gain) over the 12 week experimental period did not vary between treatment groups. Plasma LDL-C content and LDL-C/HDL-C ratio in pigs fed natural PO tended to be lower compared to all other diets. The natural PO lowered (Passociated with lower (Pweight gain or blood lipid parameters was observed between sexes. The observations on plasma TG, muscle and adipose tissue saturated fatty acid contents and back fat (subcutaneous) thickness suggest that natural palm oil may reduce deposition of body fat. In addition, dietary supplementation with natural palm oil containing palmitic acid at different positions in meat producing animals may lead to the production of meat and meat products with lower saturated fats. An increase in fat content and a decrease in lean content in female pigs resulted in an increased body fat:lean ratio but gender had no effect on blood lipid parameters or insulin concentrations.

  6. Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors.

    Science.gov (United States)

    Bonnineau, Chloé; Sague, Irene Gallardo; Urrea, Gemma; Guasch, Helena

    2012-05-01

    In multiple stress situations, the co-occurrence of environmental and chemical factors can influence organisms' ability to cope with toxicity. In this context, the influence of light adaptation on the response of freshwater biofilms to sudden light changes or to herbicides exposure was investigated by determining various parameters: diatom community composition, photosynthetic parameters, chlorophyll a content, antioxidant enzyme activities. Biofilms were grown in microcosms under sub-optimal, saturating, and high light intensities and showed already described characteristics of shade/light adaptation (community structure, photosynthetic adaptation, etc.). Light history modulated antioxidant and photosynthetic responses of biofilms to the stress caused by short-term exposure to sudden light changes or to herbicides. First biofilms adapted to sub-optimal light intensity (shade-adapted) were found to be more sensitive to an increase in light intensity than high-light adapted ones to a reduction in light intensity. Second, while light history influenced biofilms' response to glyphosate, it had little influence on biofilms' response to copper and none on its response to oxyfluorfen. Indeed glyphosate exposure led to a stronger decrease in photosynthetic efficiency of shade-adapted biofilms (EC(50) = 11.7 mg L(-1)) than of high-light adapted communities (EC(50) = 35.6 mg L(-1)). Copper exposure led to an activation of ascorbate peroxidase (APX) in biofilms adapted to sub-optimal and saturating light intensity while the protein content decreased in all biofilms exposed to copper. Oxyfluorfen toxicity was independent of light history provoking an increase in APX activity. In conclusion this study showed that both previous exposure to contaminants and physical habitat characteristics might influence community tolerance to disturbances strongly.

  7. A natural analogue for high-level waste in tuff: Chemical analysis and modeling of the Valles site

    Energy Technology Data Exchange (ETDEWEB)

    Stockman, H.W.; Krumhansl, J.L.; Ho, C.K. [Sandia National Labs., Albuquerque, NM (United States); Kovach, L. [US Nuclear Regulatory Commission, Washington, DC (United States); McConnell, V.S. [Univ. of Alaska, Fairbanks, AK (United States)

    1995-03-01

    The contact between an obsidian flow and a steep-walled tuff canyon was examined as an analogue for a high-level waste repository. The analogue site is located in the Valles Caldera in New Mexico, where a massive obsidian flow filled a paleocanyon in the Battleship Rock Tuff. The obsidian flow provided a heat source, analogous to waste panels or an igneous intrusion in a repository, and caused evaporation and migration of water. The tuff and obsidian samples were analyzed for major and trace elements and mineralogy by INAA, XRF, x-ray diffraction, and scanning electron microscopy and electron microprobe. Samples were also analyzed for D/H and {sup 39}Ar/{sup 40}Ar isotopic composition. Overall, the effects of the heating event seem to have been slight and limited to the tuff nearest the contact. There is some evidence of devitrification and migration of volatiles in the tuff within 10 m of the contact, but variations in major and trace element chemistry are small and difficult to distinguish from the natural (pre-heating) variability of the rocks.

  8. Biological and chemical evaluation of sewage water pollution in the Rietvlei nature reserve wetland area, South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Oberholster, P.J. [CSIR Natural Resources and the Environment, P.O. Box 395, Pretoria 0001 (South Africa)], E-mail: anna.oberholster@up.ac.za; Botha, A.-M. [Department of Genetics, University of Pretoria, Hillcrest, Pretoria ZA002 (South Africa); Cloete, T.E. [Department of Microbiology and Plant Pathology, University of Pretoria, Hillcrest, Pretoria ZA002 (South Africa)

    2008-11-15

    Macroinvertebrate communities in Rietvlei nature reserve wetland area and their relationship with water quality were studied with the aim to evaluate their use as potential indicators of pollution. Sampling locations were selected to include outlets from swage effluent, agricultural and informal residential runoff. A large increase in nutrient concentrations was observed downstream from discharged treated sewage with an associated decrease in species richness. Bioassays performed included: Daphnia magna, Hydra attenuate, Lactuca sativa, Allium cepa and Pyxicephalus adspersus. The highest percentage of lethality response to a screen (100% concentration) of sampled wetland water by test specimens were observed at the point source input of the Hartbeespoort treated sewage plant. Data generated from the AUSRIVAS method and multitrophic level bioassays revealed the deterioration of the wetland possibly due to factors such as increasing urbanization, industrialization, agriculture runoff and rapid human settlement in the Hennops River catchment area and its principal tributaries. - Bioassays confirmed the degradation of a freshwater wetland system due to effluent from a variety of sources.

  9. ["The Society for letters and natural science" The young Ole H. Mynster and the chemical revolution around 1800].

    Science.gov (United States)

    Hansen, Sven Erik

    2015-01-01

    Ole H. Mynster (1772-1818) was a stepson of the leading physician at the Royal Frederik Hospital in Copenhagen. At an early age he became fond of zoology and mineralogy. He created "societies" in Enlightenment-style for boys and young people with lectures and collections. Later on a circle of talented young students, scientists and poets met in his small room at the hospital. Some of them with Ole Mynster as the head set up a modern scientific journal, Physicalsk, oeconomisk og medicochirurgisk Bibliotek for Danmark og Norge which encouraged the introduction of antiphlogistic chemistry. Ole Mynster became physician at the Royal Frederik Hospital and lecturer in clinical pharmacology. He wrote the first book in Danish on pharmacology based upon chemistry. In their memoirs, prominent members of his circle have told about him, and his son F.L. Mynster has written a draft for a biography. An overview of the activities within natural science and medicine of the young Ole Hieronymus Mynster is presented.

  10. Interim report task 2: performance testing - task 2.4: natural mineral analog studies physical and chemical characteristics of brannerite in natural systems to Lawrence Livermore National Laboratory under contract B345772

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, G R; Colella, M; Leung, S H F

    2000-04-30

    To investigate the long-term alteration behavior of brannerite, we have undertaken a study of 13 natural samples from various geological environments, including granites, granitic pegmatites, quartz veins, and placer deposits. Literature data and U-Th-Pb chemical dating carried out in this work indicate that the samples range in age from approximately 20 Ma to 1580 Ma. Where independent age data or estimates are available for comparison, the U-Th-Pb chemical ages are in reasonable agreement for the younger samples, but the older samples tend to show evidence for Pb loss (up to about 80%), a common feature of metamict Nb, Ta, and Ti oxide minerals. Our results show that many of the samples exhibit only minor alteration, usually within small patches, microfractures, or around the rims of the brannerite crystals. Other samples consist of variable amounts of unaltered and altered brannerite. Heavily altered samples may contain anatase and thorite as fine-grained alteration products. Certain samples exhibited fracturing of the associated rock matrix or mineral phase in the immediate vicinity of the brannerite grains. These fractures contain U bearing material and indicate that some U migrated locally from the source brannerite.

  11. NMR fingerprints of the drug-like natural-product space identify iotrochotazine A: a chemical probe to study Parkinson's disease.

    Science.gov (United States)

    Grkovic, Tanja; Pouwer, Rebecca H; Vial, Marie-Laure; Gambini, Luca; Noël, Alba; Hooper, John N A; Wood, Stephen A; Mellick, George D; Quinn, Ronald J

    2014-06-10

    The NMR spectrum of a mixture of small molecules is a fingerprint of all of its components. Herein, we present an NMR fingerprint method that takes advantage of the fact that fractions contain simplified NMR profiles, with minimal signal overlap, to allow the identification of unique spectral patterns. The approach is exemplified in the identification of a novel natural product, iotrochotazine A (1), sourced from an Australian marine sponge Iotrochota sp. Compound 1 was used as a chemical probe in a phenotypic assay panel based on human olfactory neurosphere-derived cells (hONS) from idiopathic Parkinson's disease patients. Compound 1 at 1 μM was not cytotoxic but specifically affected the morphology and cellular distribution of lysosomes and early endosomes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. 40 CFR 68.195 - Required corrections.

    Science.gov (United States)

    2010-07-01

    ...) CHEMICAL ACCIDENT PREVENTION PROVISIONS Risk Management Plan § 68.195 Required corrections. The owner or... accident history information—For any accidental release meeting the five-year accident history reporting...

  13. Utilization of wastewater originated from naturally fermented virgin coconut oil manufacturing process for bioextract production: physico-chemical and microbial evolution.

    Science.gov (United States)

    Tripetchkul, Sudarut; Kusuwanwichid, Sasithorn; Koonsrisuk, Songpon; Akeprathumchai, Saengchai

    2010-08-01

    Production of virgin coconut oil via natural fermentation has led to large amount of wastes being generated, i.e., coconut pulp and wastewater containing coconut crème. Objective of this study is to gain more insight into the feasibility of utilization of such wastes as raw materials together with several types of wastes such as fish waste and/or pineapple peel for bioextract production. Chemical, physico-chemical and biological changes including phytotoxicity of the fermented mixture were closely monitored. Physical observation suggested that fermentation of bioextract obtained with fish waste appeared to be complete within the first month of fermentation while bioextract obtained using pineapple waste seemed to be complete after 8 months post-fermentation. Fermentation broth is of blackish color with alcoholic as well as acidic odour with no gas bubble and/or yeast film present on top of the surface. During the whole fermentation interval, several attributes of both bioextracts, e.g., pH, chemical oxygen demand (COD) and organic acids, were statistically different. Further, the total bacteria and lactic acid bacteria present in pineapple bioextract were statistically higher than those of the fish bioextract (ppineapple bioextracts, respectively. In addition, qualities of both bioextracts conformed well with those specified by the Thai standard for liquid biofertilizer after 1 month fermentation. Results further showed that wastewater derived from virgin coconut oil manufacturing process could effectively be employed together with other types of wastes such as fish waste and pineapple peel for bioextract production. However, for the best bioextract quality, fermentation should be carefully planned since over fermentation led to bioextract of low qualities. Copyright 2010 Elsevier Ltd. All rights reserved.

  14. 78 FR 75449 - Miscellaneous Corrections; Corrections

    Science.gov (United States)

    2013-12-12

    ... cross- references, correcting grammatical errors, revising language for clarity and consistency, and... practice. Specifically, these amendments are to correct grammatical errors and to revise cross-references.... The final rule contained minor errors in grammar, punctuation, and referencing. This document corrects...

  15. Hygienic and microbiological influences exerted on natural water biotopes by algae and the growth of water plants. 2. Communication: improvement of the chemical and bacteriological water quality by the natural growth of aquatic plants (author's transl)

    Energy Technology Data Exchange (ETDEWEB)

    Graef, W.; Kersch, D.; Pawlofsky, C.M.

    1981-12-01

    For a natural pond, whose waters are used for recreational purposes (swimming) and are subject to waste water inflow, the biological purifying function of a zone overgrown with reeds and aquatic plants was ascertained by means of chemical and bacteriological water quality parameters. In the years from 1975 to 1980 the contents of ammonia, nitrites, nitrates, phosphates and chlorides as well as the colony counts (CFU/ml), the coli titres and the content of fruiting myxobacteria were determined from water samples, both during the lush-growth summer period and the low-growth winter season. The location of the 6 sampling points systematically extended from the sewage outlet via the tributary ditch, in front of and behind the natural growth zone as far as the swimming waters. The test series showed - that in the tributary ditch and especially during the passage through the upper water zone densely overgrown with aquatic plants, the proportion of degradable nitrogen compounds and phosphates is distinctly reduced beyond the extent of reduction by dilution processes, - that the colony counts in the effluent water as well as the content of E. coli and of the fruiting myxobacteria, which act as indirect faecal indicator, are also reduced considerably, - that the biological purifying of the vegetation zone is definitely higher in summer than during the low-growth winter months. From this the conclusion can be drawn that for maintaining and furthering an adequate water quality of recreational waters compromised by waste water, the preservation of the naturally growing aquatic plants both in the water itself and on the banks is absolutely necessary.

  16. Determining the order of deposition of natural latent fingerprints and laser printed ink using chemical mapping with secondary ion mass spectrometry.

    Science.gov (United States)

    Attard Montalto, Nicola; Ojeda, Jesús J; Jones, Benjamin J

    2013-03-01

    Time-of-flight secondary ion mass spectrometry (ToF-SIMS) chemical mapping was used to investigate the order of deposition of natural latent fingerprints and laser printed ink on paper. This feasibility study shows that sodium, potassium and C(3)H(5) positive ions were particularly abundant endogenous components of the natural fingerprints and also present in the paper examined, but were mostly absent in the laser printed ink. Mapping of these ions enables the observation of friction ridges from latent prints on the ink surface, only when a fingerprint was deposited above the layer of ink. As a demonstration of proof of concept, blind testing of 21 samples from three donors resulted in a 100% success rate. The sensitivity of this technique was investigated within this trial through the examination of up to fifth depletion fingerprints and ageing of up to 28 days. Migration of fingerprint and paper components to the ink surface, although observed with increased ageing time, was not found to compromise determination of the deposition sequence. Copyright © 2012. Published by Elsevier Ireland Ltd.

  17. Differential effects of natural palm oil, chemically- and enzymatically-modified palm oil on weight gain, blood lipid metabolites and fat deposition in a pediatric pig model

    Science.gov (United States)

    2011-01-01

    Background Increasing prevalence of obesity and overweight in the Western world, continue to be a major health threat and is responsible for increased health care costs. Dietary intervention studies show a strong positive association between saturated fat intake and the development of obesity and cardiovascular disease. This study investigated the effect of positional distribution of palmitic acid (Sn-1, 2 & 3) of palm oil on cardiovascular health and development of obesity, using weaner pigs as a model for young children. Methods Male and female weaner piglets were randomly allocated to 4 dietary treatment groups: 1) pork lard (LRD); 2) natural palm olein (NPO); 3) chemically inter-esterified PO (CPO) and 4) enzymatically inter-esterified PO (EnPO) as the fat source. Diets were formulated with 11% lard or with palm olein in order to provide 31% of digestible energy from fat in the diet and were balanced for cholesterol, protein and energy across treatments. Results From 8 weeks onwards, pigs on EnPO diet gained (P palm oil may reduce deposition of body fat. In addition, dietary supplementation with natural palm oil containing palmitic acid at different positions in meat producing animals may lead to the production of meat and meat products with lower saturated fats. An increase in fat content and a decrease in lean content in female pigs resulted in an increased body fat:lean ratio but gender had no effect on blood lipid parameters or insulin concentrations. PMID:21586170

  18. Correcting ligands, metabolites, and pathways

    Directory of Open Access Journals (Sweden)

    Vriend Gert

    2006-11-01

    Full Text Available Abstract Background A wide range of research areas in bioinformatics, molecular biology and medicinal chemistry require precise chemical structure information about molecules and reactions, e.g. drug design, ligand docking, metabolic network reconstruction, and systems biology. Most available databases, however, treat chemical structures more as illustrations than as a datafield in its own right. Lack of chemical accuracy impedes progress in the areas mentioned above. We present a database of metabolites called BioMeta that augments the existing pathway databases by explicitly assessing the validity, correctness, and completeness of chemical structure and reaction information. Description The main bulk of the data in BioMeta were obtained from the KEGG Ligand database. We developed a tool for chemical structure validation which assesses the chemical validity and stereochemical completeness of a molecule description. The validation tool was used to examine the compounds in BioMeta, showing that a relatively small number of compounds had an incorrect constitution (connectivity only, not considering stereochemistry and that a considerable number (about one third had incomplete or even incorrect stereochemistry. We made a large effort to correct the errors and to complete the structural descriptions. A total of 1468 structures were corrected and/or completed. We also established the reaction balance of the reactions in BioMeta and corrected 55% of the unbalanced (stoichiometrically incorrect reactions in an automatic procedure. The BioMeta database was implemented in PostgreSQL and provided with a web-based interface. Conclusion We demonstrate that the validation of metabolite structures and reactions is a feasible and worthwhile undertaking, and that the validation results can be used to trigger corrections and improvements to BioMeta, our metabolite database. BioMeta provides some tools for rational drug design, reaction searches, and

  19. Differential effects of natural palm oil, chemically- and enzymatically-modified palm oil on weight gain, blood lipid metabolites and fat deposition in a pediatric pig model

    Directory of Open Access Journals (Sweden)

    Dunshea Frank R

    2011-05-01

    Full Text Available Abstract Background Increasing prevalence of obesity and overweight in the Western world, continue to be a major health threat and is responsible for increased health care costs. Dietary intervention studies show a strong positive association between saturated fat intake and the development of obesity and cardiovascular disease. This study investigated the effect of positional distribution of palmitic acid (Sn-1, 2 & 3 of palm oil on cardiovascular health and development of obesity, using weaner pigs as a model for young children. Methods Male and female weaner piglets were randomly allocated to 4 dietary treatment groups: 1 pork lard (LRD; 2 natural palm olein (NPO; 3 chemically inter-esterified PO (CPO and 4 enzymatically inter-esterified PO (EnPO as the fat source. Diets were formulated with 11% lard or with palm olein in order to provide 31% of digestible energy from fat in the diet and were balanced for cholesterol, protein and energy across treatments. Results From 8 weeks onwards, pigs on EnPO diet gained (P Conclusions The observations on plasma TG, muscle and adipose tissue saturated fatty acid contents and back fat (subcutaneous thickness suggest that natural palm oil may reduce deposition of body fat. In addition, dietary supplementation with natural palm oil containing palmitic acid at different positions in meat producing animals may lead to the production of meat and meat products with lower saturated fats. An increase in fat content and a decrease in lean content in female pigs resulted in an increased body fat:lean ratio but gender had no effect on blood lipid parameters or insulin concentrations.

  20. Iodine distribution in natural waters of different chemical composition in relation to water-bearing soils and rocks and water fractions in areas subjected to radioiodine contamination

    Science.gov (United States)

    Kolmykova, Liudmila; Korobova, Elena

    2017-04-01

    Iodine is an essential microelement required for normal functioning of thyroid gland. Natural deficiency of stable iodine is compensated by its active intake by thyroid and provokes its higher irradiation in case of radiation accidents and contamination of the environment by radioiodine isotopes. The bioavailability of both stable and radioactive iodine and the specificity of its uptake by living organisms largely depends on geochemical parameters of the environment related to natural conditions of water migration. The goal of the study was to investigate spatial distribution of iodine in natural water of different chemical composition in relation to typical water-bearing soils and rocks and water fractions in Bryansk areas subjected to radioiodine contamination after the Chernobyl accident and to evaluate contribution of this factor to the occurrence of endemic thyroid diseases among local population inhabiting geochemically different areas of fluvioglacial and loess-like sedimentary rocks. The highest content of iodine (Me=13.3 µg/l) was observed in surface water of landscapes with H-Ca, Ca and H-Ca-Fe classes of water migration. The lowest microelement level (Me=5.25 µg/l) was noted in groundwater of landscapes with H, H-Fe classes of water migration in areas of Paleogene water bearing rocks. Regardless of the type of source and class of water migration up to 90% of the total content of iodide is present in the fraction membrane filtration). Up to 50% of iodine pass to solution containing particles water in areas of loess-like sedimentary rocks hosts the highest levels of iodine where its associated with calcium mineral aquatic complexes and the suspended particles. The obtained data is believed to be useful in explanation of mobility and intake of iodine and its radioactive analogues by rural population living in different geochemical conditions and using local drinking waters. The data should be accounted of in planning prophylactics of endemic diseases and

  1. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... and Craniofacial Surgery Cleft Lip/Palate and Craniofacial Surgery A cleft lip may require one or more ... find out more. Corrective Jaw Surgery Corrective Jaw Surgery Orthognathic surgery is performed to correct the misalignment ...

  2. Storm water runoff measurements of copper from a naturally patinated roof and from a parking space. Aspects on environmental fate and chemical speciation.

    Science.gov (United States)

    Odnevall Wallinder, I; Hedberg, Y; Dromberg, P

    2009-12-01

    Release of copper from a naturally aged copper roof on a shopping centre building in a suburban site of Stockholm has been measured during different rain events after its interaction with the internal drainage system and storm drains made of cast iron and concrete. Concentrations of copper removed by means of urban storm water from a nearby parking space have been determined for comparison. Predictions and measurements of the chemical speciation of released copper are discussed compared to the total concentration, and to threshold values for freshwater and drinking water. The results clearly illustrate that the major part of the released copper from the roof is readily retained already during transport through the internal drainage system of the building, a pathway that also changes the chemical speciation of released copper and its bioavailable fraction. Most copper, not retained by cast iron and concrete surfaces, was strongly complexed to organic matter. The median concentration of free cupric ions and weak copper complexes was less than, or within the range of reported no effect concentrations, NOECs, of copper in surface waters. The parking space contributed with significantly higher and time-dependent concentrations of total copper compared to measured concentrations of copper from the roof after the interaction with the drainage system. Most copper in the surface runoff water was strongly complexed with organic matter, hence reducing the bioavailable fraction significantly to concentrations within the NOEC range. Dilution with other sources of urban storm water will reduce the released concentration of copper even further. The results illustrate that already the internal drainage system and the storm drains made of cast iron and concrete act as efficient sinks for released copper which means that any installation of additional infiltration devices is redundant.

  3. Intermolecular CH···O/N H-bonds in the biologically important pairs of natural nucleobases: a thorough quantum-chemical study.

    Science.gov (United States)

    Brovarets', Ol'ha O; Yurenko, Yevgen P; Hovorun, Dmytro M

    2014-01-01

    This study aims to cast light on the physico-chemical nature and energetic of the non-conventional CH···O/N H-bonds in the biologically important natural nucleobase pairs using a comprehensive quantum-chemical approach. As a whole, the 36 biologically important pairs, involving canonical and rare tautomers of nucleobases, were studied by means of all available up-to-date state-of-the-art quantum-chemical techniques along with quantum theory "Atoms in molecules" (QTAIM), Natural Bond Orbital (NBO) analysis, Grunenberg's compliance constants theory, geometrical and vibrational analyses to identify the CH···O/N interactions, reveal their physico-chemical nature and estimate their strengths as well as contribution to the overall base-pairs stability. It was shown that all the 38 CH···O/N contacts (25 CH···O and 13 CH···N H-bonds) completely satisfy all classical geometrical, electron-topological, in particular Bader's and "two-molecule" Koch and Popelier's, and vibrational criteria of H-bonding. The positive values of Grunenberg's compliance constants prove that the CH···O/N contacts in nucleobase pairs are stabilizing interactions unlike electrostatic repulsion and anti-H-bonds. NBO analysis indicates the electron density transfer from the lone electron pair of the acceptor atom (O/N) to the antibonding orbital corresponding to the donor group σ(∗)(CH). Moreover, significant increase in the frequency of the out-of-plane deformation modes γ (CH) under the formation of the CH···O (by 17.2÷81.3/10.8÷84.7 cm(-1)) and CH···N (by 32.7÷85.9/9.0÷77.9 cm(-1)) H-bonds at the density functional theory (DFT)/second-order Møller-Plesset (MP2) levels of theory, respectively, and concomitant changes of their intensities can be considered as reliable indicators of H-bonding. The strengths of the CH···O/N interactions, evaluated by means of Espinosa-Molins-Lecomte formula, lie within the range 0.45÷3.89/0.62÷4.10 kcal/mol for the CH

  4. A natural orbital analysis of the long range behavior of chemical bonding and van der Waals interaction in singlet H2: the issue of zero natural orbital occupation numbers.

    Science.gov (United States)

    Sheng, X W; Mentel, Ł M; Gritsenko, O V; Baerends, E J

    2013-04-28

    This paper gives a natural orbital (NO) based analysis of the van der Waals interaction in (singlet) H2 at long distance. The van der Waals interaction, even if not leading to a distinct van der Waals well, affects the shape of the interaction potential in the van der Waals distance range of 5-9 bohrs and can be clearly distinguished from chemical bonding effects. In the NO basis the van der Waals interaction can be quantitatively covered with, apart from the ground state configurations (1σ(g))(2) and (1σ(u))(2), just the 4 configurations (2σ(g))(2) and (2σ(u))(2), and (1π(u))(2) and (1π(g))(2). The physics of the dispersion interaction requires and explains the peculiar relatively large positive CI coefficients of the doubly excited electron configurations (2σ(u))(2) and (1π(g))(2) (the occupancy amplitudes of the 2σ(u) and 1π(gx, y) NOs) in the distance range 5-9 bohrs, which have been observed before by Cioslowski and Pernal [Chem. Phys. Lett. 430, 188 (2006)]. We show that such positive occupancy amplitudes do not necessarily lead to the existence of zero occupation numbers at some H-H distances.

  5. Comparison of Fe-Al-modified natural materials by an electrochemical method and chemical precipitation for the adsorption of F- and As(V).

    Science.gov (United States)

    Vázquez Mejía, G; Martínez-Miranda, V; Fall, C; Linares-Hernández, I; Solache-Ríos, M

    2016-01-01

    The adsorption of fluoride and arsenic ions by modified natural materials may have an impact on the removal of F- and As(V) from waters. In this work, a zeolitic material and pozzolan (commonly known as pumicite) were modified with aluminium an iron by an electrochemical method and chemical precipitation, respectively. The adsorbents were characterized by X-ray diffraction, scanning electron microscopy with energy X-ray disperse spectroscopy analysis and the point of zero charge (pHzpc). F- and As(V) adsorption properties of both materials were investigated. Adsorption kinetic data were best fitted to pseudo-second-order model and equilibrium data to the Langmuir isotherm model. The highest F- and As(V) sorption capacities were obtained for modified zeolitic (0.866 mg/g) and pozzolan (3.35 mg/g) materials, respectively, with initial F- or As(V) concentrations of 10 mg/L. It was found that the unmodified materials did not show either adsorption of F- ions or As(V), which indicated that Al and Fe in the adsorbents are responsible for the adsorption of these ions. In general, both modified materials show similar capacities for the adsorption of F- and As(V).

  6. Mineralogical, chemical and K-Ar isotopic changes in Kreyenhagen Shale whole rocks and clay fractions during natural burial and hydrous-pyrolysis experimental maturation

    Science.gov (United States)

    Clauer, N.; Lewan, M. D.; Dolan, M. P.; Chaudhuri, S.; Curtis, J. B.

    2014-04-01

    Progressive maturation of the Eocene Kreyenhagen Shale from the San Joaquin Basin of California was studied by combining mineralogical and chemical analyses with K-Ar dating of whole rocks and clay fractions from naturally buried samples and laboratory induced maturation by hydrous pyrolysis of an immature outcrop sample. The K-Ar age decreases from 89.9 ± 3.9 and 72.4 ± 4.2 Ma for the outcrop whole rock and its bitumen. This hindrance is interpreted to result from bitumen impregnating the smectite interlayer sites and rock matrix. Bitumen remains in the clay fraction to fully expand or collapse once bitumen generation from the thermal decomposition of the kerogen is completed, and by almost invariable K-Ar ages confirming for the lack of any K supply and/or radiogenic 40Ar removal. This suggests that once bitumen impregnates the porosity of a progressively maturing source rock, the pore system is no longer wetted by water and smectite to illite conversion ceases. Experimental attempts to evaluate the smectite conversion to illite should preferentially use low-TOC rocks to avoid inhibition of the reaction by bitumen impregnation.

  7. Modification of chemical and conformational properties of natural organic matter by click chemistry as revealed by ESI-Orbitrap mass spectrometry.

    Science.gov (United States)

    Nebbioso, Antonio; Piccolo, Alessandro

    2015-11-01

    A click reaction is reported here for the first time as a useful technique to control the conformational stability of natural organic matter (NOM) suprastructures. Click conjugates were successfully formed between a previously butynylated NOM hydrophobic fraction and a hydrophilic polyethylene glycol (PEG)-amino chain. The click products were shown by size exclusion chromatography (HPSEC) hyphenated with Orbitrap mass spectrometry (MS) in electrospray ionization (ESI) (+), while precursors were visible in ESI (-). Despite their increase in molecular weight, HPSEC elution of click conjugates occurred after that of precursors, thus showing their departure from the NOM supramolecular association. This indicates that the click-conjugated NOM molecules were varied in their hydrophilic and cationic character and lost the capacity to accommodate in the original hydrophobic suprastructures. The most abundant product had the C16H30O5N4 formula, a click conjugate of butanoic acid, while other products were short-chained (C4-C8) linear unsaturated and hydroxylated carboxylic acids. Tandem MS revealed formation of triazole rings in clicked conjugates and their two fragmentations at the ester and the C-N alkyl-aryl bonds. The behavior of NOM molecules modified by click chemistry confirms that hydrophobicity and ionic charge of humic molecules play a pivotal role in stabilizing intermolecular forces in NOM. Moreover, the versatility of the click reaction may become useful to decorate NOM molecules with a variety of substrates, in order to alter NOM conformational and chemical properties and diversify its applications in the environment.

  8. Chemical Compositions of the Peel Essential Oil of Citrus aurantium and its Natural Larvicidal Activity against the Malaria Vector Anopheles stephensi (Diptera: Culicidae in Comparison with Citrus paradisi

    Directory of Open Access Journals (Sweden)

    Alireza Sanei-Dehkordi

    2016-10-01

    Full Text Available Background: Recently, essential oils and extracts derived from plants have received much interest as potential bioactive agents against mosquito vectors.Methods: The essential oils extract from fresh peel of ripe fruit of Citrus aurantium and Citrus paradisi were tested against mosquito vector Anopheles stephensi (Diptera: Culicidae under laboratory condition. Then chemical com­position of the essential oil of C. aurantium was analyzed using gas chromatography-mass spectrometry (GC–MS.Results: The essential oils obtained from C. aurantium, and C. paradisi showed good larviciding effect against An. stephensi with LC50 values 31.20 ppm and 35.71 ppm respectively. Clear dose response relationships were established with the highest dose of 80 ppm plant extract evoking almost 100% mortality. Twenty-one (98.62% constituents in the leaf oil were identified. The main constituent of the leaf oil was Dl-limonene (94.81.Conclusion: The results obtained from this study suggest that the limonene of peel essential oil of C. aurantium is promising as larvicide against An. stephensi larvae and could be useful in the search for new natural larvicidal compounds.

  9. EDITORIAL: Politically correct physics?

    Science.gov (United States)

    Pople Deputy Editor, Stephen

    1997-03-01

    If you were a caring, thinking, liberally minded person in the 1960s, you marched against the bomb, against the Vietnam war, and for civil rights. By the 1980s, your voice was raised about the destruction of the rainforests and the threat to our whole planetary environment. At the same time, you opposed discrimination against any group because of race, sex or sexual orientation. You reasoned that people who spoke or acted in a discriminatory manner should be discriminated against. In other words, you became politically correct. Despite its oft-quoted excesses, the political correctness movement sprang from well-founded concerns about injustices in our society. So, on balance, I am all for it. Or, at least, I was until it started to invade science. Biologists were the first to feel the impact. No longer could they refer to 'higher' and 'lower' orders, or 'primitive' forms of life. To the list of undesirable 'isms' - sexism, racism, ageism - had been added a new one: speciesism. Chemists remained immune to the PC invasion, but what else could you expect from a group of people so steeped in tradition that their principal unit, the mole, requires the use of the thoroughly unreconstructed gram? Now it is the turn of the physicists. This time, the offenders are not those who talk disparagingly about other people or animals, but those who refer to 'forms of energy' and 'heat'. Political correctness has evolved into physical correctness. I was always rather fond of the various forms of energy: potential, kinetic, chemical, electrical, sound and so on. My students might merge heat and internal energy into a single, fuzzy concept loosely associated with moving molecules. They might be a little confused at a whole new crop of energies - hydroelectric, solar, wind, geothermal and tidal - but they could tell me what devices turned chemical energy into electrical energy, even if they couldn't quite appreciate that turning tidal energy into geothermal energy wasn't part of the

  10. Human exposure to unconventional natural gas development: A public health demonstration of periodic high exposure to chemical mixtures in ambient air.

    Science.gov (United States)

    Brown, David R; Lewis, Celia; Weinberger, Beth I

    2015-01-01

    Directional drilling and hydraulic fracturing of shale gas and oil bring industrial activity into close proximity to residences, schools, daycare centers and places where people spend their time. Multiple gas production sources can be sited near residences. Health care providers evaluating patient health need to know the chemicals present, the emissions from different sites and the intensity and frequency of the exposures. This research describes a hypothetical case study designed to provide a basic model that demonstrates the direct effect of weather on exposure patterns of particulate matter smaller than 2.5 microns (PM2.5) and volatile organic chemicals (VOCs). Because emissions from unconventional natural gas development (UNGD) sites are variable, a short term exposure profile is proposed that determines 6-hour assessments of emissions estimates, a time scale needed to assist physicians in the evaluation of individual exposures. The hypothetical case is based on observed conditions in shale gas development in Washington County, Pennsylvania, and on estimated emissions from facilities during gas development and production. An air exposure screening model was applied to determine the ambient concentration of VOCs and PM2.5 at different 6-hour periods of the day and night. Hourly wind speed, wind direction and cloud cover data from Pittsburgh International Airport were used to calculate the expected exposures. Fourteen months of daily observations were modeled. Higher than yearly average source terms were used to predict health impacts at periods when emissions are high. The frequency and intensity of exposures to PM2.5 and VOCs at a residence surrounded by three UNGD facilities was determined. The findings show that peak PM2.5 and VOC exposures occurred 83 times over the course of 14 months of well development. Among the stages of well development, the drilling, flaring and finishing, and gas production stages produced higher intensity exposures than the

  11. Comparison of Chemical Profiles, Anti-Inflammatory Activity, and UPLC-Q-TOF/MS-Based Metabolomics in Endotoxic Fever Rats between Synthetic Borneol and Natural Borneol

    Directory of Open Access Journals (Sweden)

    Liang Zou

    2017-08-01

    Full Text Available Natural borneol (NB, called “Bingpian” is an important traditional Chinese medicine to restore consciousness, remove heat and relieve pain, all of which are inflammation-related diseases. Recently, due to the limited source of NB, synthetic borneol (SB is widely used as a substitute for NB in clinics. However, little is known about the effects of SB instead of NB. Herein, the aim of the present study was to compare NB and SB on chemical profiles by gas chromatography-mass spectrometer (GC-MS analysis, anti-inflammatory activity in lipopolysaccharide (LPS-induced RAW 264.7 macrophages, and ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS metabolomic approaches in endotoxic fever induced in rats. Results showed that, in total, 13 volatile components could be identified in NB and SB by GC-MS analysis, in which a significant difference between them still existed. The main constituents in SB were iso-borneol and borneol, while borneol contributes to 98.96% of the amount in NB. Additionally, both NB and SB exhibited remarkable anti-inflammatory effects to reduce the level of inflammatory factors including NO, TNF-α and IL-6 in LPS-induced RAW 264.7 macrophages, and lower the high body temperature in rats with endotoxic fever induced by LPS. Moreover, it seems that NB exhibited higher efficacy than SB. The unequal bioactive efficiency between NB and SB was also indicated by means of non-targeting metabolomics. Based on UPLC-Q-TOF/MS technology, 12 biomarkers in the serum of fever rats were identified. Pathway analysis revealed that the anti-fever effect of NB and SB was related to regulating the abnormal glycerophospholipid, linoleic acid and alpha-linoleic acid metabolism pathways in the fever model. Results indicated that there was still a great difference between NB and SB involving chemical constituents, anti-inflammation activity and the ability to regulate the abnormal metabolism pathways of

  12. Chemical nature of soil humified fractions and their bioactivity Natureza química do húmus do solo e sua bioatividade

    Directory of Open Access Journals (Sweden)

    Luciano Pasqualoto Canellas

    2004-03-01

    Full Text Available The aim of this work was to evaluate the humus composition from an Ultisol from Campos dos Goytacazes, RJ, Brazil. Soil samples of four depths (0-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.40 m and its chemical nature were analysed by elemental composition, E4/E6 ratios and Fourier transformed infrared spectroscopy. The bioactivity of these humified substances was evaluated through their action on maize root growth and H+-ATPase activity of roots microsomes. In topsoil, the content of high condensed alkaline soluble humic substances is greater than that found in the subsuperficial layers. The chemical nature of humic and fulvic acids also varied with the soil depth. The humic acids isolated from the soil samples exhibited higher bioactivity compared with the fulvic acids. Moreover, the results suggest that more condensed humic substances can promote highest stimulation of the microsomal H+-ATPases from maize roots. These data reinforce the concept that the activity of the H+ pumps can be used as a biochemical marker for evaluation of humic substances bioactivity.O objetivo deste trabalho foi avaliar a composição do húmus de um Argissolo Amarelo de Campos dos Goytacazes, RJ, Brasil. Amostras de solo de quatro profundidades (0-0,05, 0,05-0,10, 0,10-0,20 e 0,20-0,40 m foram analisados mediante o fracionamento químico da matéria orgânica. As frações ácidos húmicos e fúlvicos foram extraídas e sua natureza química avaliada por meio da composição elementar, relação E4/E6 e espectroscopia de infravermelho transformada de Fourier. A bioatividade das substâncias húmicas foi avaliada mediante sua ação sobre o crescimento radicular de plântulas de milho e atividade da H+-ATPase da fração microssomal das raízes. Os resultados mostraram que é maior o conteúdo de substâncias húmicas alcalino solúveis mais condensadas na camada superficial do solo. A natureza química dos ácidos húmicos e fúlvicos também variou com a profundidade

  13. Cob(I)alamin: insight into the nature of electronically excited states elucidated via quantum chemical computations and analysis of absorption, CD and MCD data.

    Science.gov (United States)

    Kornobis, Karina; Ruud, Kenneth; Kozlowski, Pawel M

    2013-02-07

    The nature of electronically excited states of the super-reduced form of vitamin B(12) (i.e., cob(I)alamin or B(12s)), a ubiquitous B(12) intermediate, was investigated by performing quantum-chemical calculations within the time-dependent density functional theory (TD-DFT) framework and by establishing their correspondence to experimental data. Using response theory, the electronic absorption (Abs), circular dichroism (CD) and magnetic CD (MCD) spectra of cob(I)alamin were simulated and directly compared with experiment. Several issues have been taken into considerations while performing the TD-DFT calculations, such as strong dependence on the applied exchange-correlation (XC) functional or structural simplification imposed on the cob(I)alamin. In addition, the low-lying transitions were also validated by performing CASSCF/MC-XQDPT2 calculations. By comparing computational results with existing experimental data a new level of understanding of electronic excitations has been established at the molecular level. The present study extends and confirms conclusions reached for other cobalamins. In particular, the better performance of the BP86 functional, rather than hybrid-type, was observed in terms of the excitations associated with both Co d and corrin π localized transitions. In addition, the lowest energy band was associated with multiple metal-to-ligand charge transfer excitations as opposed to the commonly assumed view of a single π → π* transition followed by vibrational progression. Finally, the use of the full cob(I)alamin structure, instead of simplified molecular models, shed new light on the spectral analyses of cobalamin systems and revealed new challenges of this approach related to long-range charge transfer excitations involving side chains.

  14. NWS Corrections to Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Form B-14 is the National Weather Service form entitled 'Notice of Corrections to Weather Records.' The forms are used to make corrections to observations on forms...

  15. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... Jaw Surgery Download Download the ebook for further information Corrective jaw, or orthognathic surgery is performed by ... your treatment. Correction of Common Dentofacial Deformities ​ ​ The information provided here is not intended as a substitute ...

  16. Benzene; high level quantum chemical calculations, gas electron diffraction pattern recorded on Fuji imaging plates and a method to explore systematic discrepancies which was used to determine an improved sector correction

    Science.gov (United States)

    Gundersen, Snefrid; Samdal, Svein; Strand, Tor G.; Volden, Hans V.

    2007-04-01

    The C sbnd C bond distance in molecular benzene is used by several electron diffraction groups to calibrate the electron wavelength in a gas electron diffraction experiment. It is therefore important to compare the applied ra value against the currently best available ab initio re result. A high level CCSD(T = Full)/cc-pVTZ calculation, which has proven to give re distances close to the experimental values, gave re(C sbnd C) = 1.392 Å. When our wavelength calibration distance ra(C sbnd C) = 1.3975 Å is corrected for atomic displacements in the curvilinear approach and for anharmonic vibrations, it matches exactly the calculated re(C sbnd C) value. From a B3LYP/cc-pVTZ molecular force field the distance correction terms ( dhn) and the root-mean-square vibration amplitudes were computed both in the linear and the curvilinear approximations. Gas electron diffraction intensities for benzene were registered on Fuji imaging plates. The data are very reproducible and revealed that systematic discrepancies might be present. A method to investigate systematic errors in electron diffraction is proposed. A multiplicative correction likely due to very small errors in the applied sector correction could be estimated. Applying this new correction the agreement is improved due to the high reproducibility of the imaging plates, however, hardly all systematic errors are removed. The agreement is very good and the errors left are unlikely to be caused by the Fuji imaging plate system.

  17. Dissolved Organic In Natural and Polluted Waters: Methodology and Results of Running Control of Chemical Oxygen Demand (cod) For The Inland and Marine Aquatic System

    Science.gov (United States)

    Melentyev, K. V.; Worontsov, A. M.

    Current control of dissolved organic matter in natural and waste waters is the definition traditionally of chemical oxygen demand (COD) -- one of the basic parameters of quality of water. According to the International Standard (ISO 6060), it requires not less than one hour, while in many cases the operative information about amount of dissolved organic matter in aquatic environments have importance for prevention of an emergency. The standard method is applicable to waters with meaning of COD above 30 mg O2/l and, as the chloride ion prevents, it could be difficult for assessment of organic matter in sea water. Besides it is based on dichromate oxidation of the sum of organic substances in strong acid conditions at the presence of silver and mercury, that resulted in formation toxic pollutants. Till now attempts of automation of the COD definition in aquatic system were limited, basically, to duplication of the technology submitted the above standard (automatic COD analyzers "SERES Co."-- France, or "Tsvet Co." - Russia). The system of ozone-chemiluminescence automatic control of organic matter in water (CS COD) is offered and designed. Its based on the ozone oxidation of these substances in flowing water system and measurement arising from luminescent effects. CS COD works in real time. An instrument uses for reaction the atmospheric air, doesn't require fill of reagents and doesn't make new toxic pollutants. The system was tested in laboratory, and biochemical control of organic matter in water samples gathered from the river Neva and other polluted inland water areas and basins in St. Petersburg region was fulfilled (distilled water was used as "zero" media). The results of systematization of these measurements are presented. The new special ozone generator and flowing reactor for real-time running control of different waters in natural conditions were developed, and several series of large - scale field experiments onboard research ship were provided

  18. Corrective Action Investigation Plan for Corrective Action Unit 204: Storage Bunkers, Nevada Test Site, Nevada (December 2002, Revision No.: 0), Including Record of Technical Change No. 1

    Energy Technology Data Exchange (ETDEWEB)

    NNSA/NSO

    2002-12-12

    The Corrective Action Investigation Plan contains the U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office's approach to collect the data necessary to evaluate corrective action alternatives appropriate for the closure of Corrective Action Unit (CAU) 204 under the Federal Facility Agreement and Consent Order. Corrective Action Unit 204 is located on the Nevada Test Site approximately 65 miles northwest of Las Vegas, Nevada. This CAU is comprised of six Corrective Action Sites (CASs) which include: 01-34-01, Underground Instrument House Bunker; 02-34-01, Instrument Bunker; 03-34-01, Underground Bunker; 05-18-02, Chemical Explosives Storage; 05-33-01, Kay Blockhouse; 05-99-02, Explosive Storage Bunker. Based on site history, process knowledge, and previous field efforts, contaminants of potential concern for Corrective Action Unit 204 collectively include radionuclides, beryllium, high explosives, lead, polychlorinated biphenyls, total petroleum hydrocarbons, silver, warfarin, and zinc phosphide. The primary question for the investigation is: ''Are existing data sufficient to evaluate appropriate corrective actions?'' To address this question, resolution of two decision statements is required. Decision I is to ''Define the nature of contamination'' by identifying any contamination above preliminary action levels (PALs); Decision II is to ''Determine the extent of contamination identified above PALs. If PALs are not exceeded, the investigation is completed. If PALs are exceeded, then Decision II must be resolved. In addition, data will be obtained to support waste management decisions. Field activities will include radiological land area surveys, geophysical surveys to identify any subsurface metallic and nonmetallic debris, field screening for applicable contaminants of potential concern, collection and analysis of surface and subsurface soil samples from biased locations

  19. Physico-chemical characterization of natural fermentation process of Conservolea and Kalamàta table olives and developement of a protocol for the pre-selection of fermentation starters.

    Science.gov (United States)

    Bleve, Gianluca; Tufariello, Maria; Durante, Miriana; Grieco, Francesco; Ramires, Francesca Anna; Mita, Giovanni; Tasioula-Margari, Maria; Logrieco, Antonio Francesco

    2015-04-01

    Table olives are one of the most important traditional fermented vegetables in Europe and their world consumption is constantly increasing. Conservolea and Kalamàta are the most important table olives Greek varieties. In the Greek system, the final product is obtained by spontaneous fermentations, without any chemical debittering treatment. This natural fermentation process is not predictable and strongly influenced by the physical-chemical conditions and by the presence of microorganisms contaminating the olives. Natural fermentations of Conservolea and Kalamàta cultivars black olives were studied in order to determine microbiological, biochemical and chemical evolution during the process. Following the process conditions generally used by producers, in both cultivars, yeasts were detected throughout the fermentation, whereas lactic acid bacteria (LAB) appeared in the last staged of the process. A new optimized specific protocol was developed to select autochthonous yeast and LAB isolates that can be good candidates as starters. These microorganisms were pre-selected for their ability to adapt to model brines, to have beta-glucosidase activity, not to produce biogenic amines. Chemical compounds deriving by microbiological activities and associated to the three different phases (30, 90 and 180 days) of the fermentation process were identified and were proposed as chemical descriptors to follow the fermentation progress. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Coupling chemical oxidation and biostimulation: Effects on the natural attenuation capacity and resilience of the native microbial community in alkylbenzene-polluted soil

    NARCIS (Netherlands)

    Martínez-Pascual, E.; Grotenhuis, J.T.C.; Solanas, A.M.; Viñas, M.

    2015-01-01

    Coupling chemical oxidation with bioremediation could be a cost-effective system to cope with soil and groundwater pollution. However, the effects of chemical oxidation on autochthonous microbial communities are scarcely known. A detailed analysis that considers both the efficiency of the two

  1. Development of soil-cement blocks with three interventions: natural soil, soil corrected with sand and soil more phase change materials (PCMs); Desenvolvimento de blocos solo-cimento com tres intervencoes: solo natural, solo corrigido com areia e solo mais materiais de mudanca de fase (MMFs)

    Energy Technology Data Exchange (ETDEWEB)

    Dantas, Valter Bezerra; Gomes, Uilame Umbelino; Reis, Edmilson Pedreira; Valcacer, Samara Melo; Silva, A.S., E-mail: valter.fisic@hotmail.com, E-mail: umbelino@dfte.ufrn.br, E-mail: pedreira.reis@ig.com.br, E-mail: gmarinho@ct.ufrn.br, E-mail: samaravalcacer@hotamil.com, E-mail: ariadness2@yahoo.com.br [Universidade Federal do Rio Grande do Norte (PPGCEM/UFRN), Natal, RN (Brazil). Departamento de Fisica Teorica e Experimental. Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

    2014-07-01

    In this work, the results of characterization tests of soil samples collected in Mossoro-RN, UFERSA-RN Campus, located approximately 20 meters high, and {sup 5} ° 12'34.68 south latitude and 37 ° 19'5.74 {sup w}est longitude, with the purpose of producing soil-cement for the manufacture of pressed blocks with good resistance to compression and thermal stability. The following tests were performed: granulometry, plasticity limit, liquidity limit, particle size correction, scanning electron microscopy (SEM), X-ray fluorescence. In this soil, based on the results of the granulometric analysis, 10% of medium sand with 3% and 5% of eicosane paraffin and 10% of medium sand with 3% and 5% of paraffin 120 / 125F were added, forming analysis compositions, standard soil-cement block and natural soil-cement block with addition of 10% medium sand and 0% paraffin. Paraffins are referred to as PCMs (Phase Change Material). The contrasting effect between the different dosages on the compressive strength values of the soil-cement blocks was observed. The objective is to create new materials that give the block quality equal to or higher than the recommendations of ABNT norms, and that offer greater thermal comfort in the constructions. Soil particles of different sizes were added to 8% (by weight) of cement, and about 9.20% of water added to the mixture.

  2. The chemical life(1).

    Science.gov (United States)

    Hodges, Nathan

    2015-01-01

    You write this narrative autoethnography to open up a conversation about our chemical lives. You go through your day with chemical mindfulness, questioning taken-for-granted ideas about natural and artificial, healthy and unhealthy, dependency and addiction, trying to understand the chemical messages we consume through the experiences of everyday life. You reflect on how messages about chemicals influence and structure our lives and why some chemicals are celebrated and some are condemned. Using a second-person narrative voice, you show how the personal is relational and the chemical is cultural. You write because you seek a connection, a chemical bond.

  3. Corrective Action Investigation Plan for Corrective Action Unit 371: Johnnie Boy Crater and Pin Stripe Nevada Test Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Matthews

    2009-02-01

    Corrective Action Unit (CAU) 371 is located in Areas 11 and 18 of the Nevada Test Site, which is approximately 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 371 is comprised of the two corrective action sites (CASs) listed below: • 11-23-05, Pin Stripe Contamination Area • 18-45-01, U-18j-2 Crater (Johnnie Boy) These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on November 19, 2008, by representatives of the Nevada Division of Environmental Protection; U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office; Stoller-Navarro Joint Venture; and National Security Technologies, LLC. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 371. Appendix A provides a detailed discussion of the DQO methodology and the DQOs specific to each CAS. The scope of the corrective action investigation for CAU 371 includes the following activities: • Move surface debris and/or materials, as needed, to facilitate sampling. • Conduct radiological surveys. • Measure in situ external dose rates using thermoluminescent dosimeters or other dose measurement devices. • Collect and submit environmental samples for laboratory analysis to determine internal dose rates. • Combine internal and external dose rates to determine whether total

  4. Natural ventilation for free stall dairy barns

    OpenAIRE

    Gay, Susan Wood

    2009-01-01

    Natural ventilation is a result of a combination good construction, correct temperature, humidity control, air exchange. This publication discusses how to achieve natural ventilation in your structure.

  5. Cultivated strains of Agaricus bisporus and A.brasiliensis: chemical characterization and evaluation of antioxidant and antimicrobial properties for the final healthy product – natural preservatives in yoghurt

    NARCIS (Netherlands)

    Stojkovic, D.S.; Reis, F.S.; Glamoclija, J.; Ciric, A.; Barros, L.; Griensven, van L.J.L.D.; Ferreira, I.C.F.R.; Sokovic, M.

    2014-01-01

    Agaricus bisporus (J. E. Lange) Emil J. Imbach and Agaricus brasiliensis Wasser, M. Didukh, Amazonas & Stamets are edible mushrooms. We chemically characterized these mushrooms for nutritional value, hydrophilic and lipophilic compounds. The antioxidant and antimicrobial activities of methanolic

  6. The Relevance of Second Language Acquisition Theory to the Written Error Correction Debate

    Science.gov (United States)

    Polio, Charlene

    2012-01-01

    The controversies surrounding written error correction can be traced to Truscott (1996) in his polemic against written error correction. He claimed that empirical studies showed that error correction was ineffective and that this was to be expected "given the nature of the correction process and "the nature of language learning" (p. 328, emphasis…

  7. Multiple boron-boron bonds in neutral molecules: an insight from the extended transition state method and the natural orbitals for chemical valence scheme.

    Science.gov (United States)

    Mitoraj, Mariusz P; Michalak, Artur

    2011-03-21

    We have analyzed the character of B═B and B≡B bonds in the neutral molecules of general form: LHB═BHL (2-L) and LB≡BL (3-L), for various ancillary ligands L attached to the boron center, based on a recently developed method that combines the extended transition state scheme with the theory of natural orbitals for chemical valence (ETS-NOCV). In the case of molecules with the B═B bond, 2-L, we have included L = PMe(3), PF(3), PCl(3), PH(3), C(3)H(4)N(2)═C(NHCH)(2), whereas for molecules containing the B≡B connection, 3-L, the following ligands were considered L = CO, PMe(3), PCl(3), (Me(2)NCH(2)CH(2)O)(2)Ge. The results led us to conclude that use of phosphorus ligands leads to strengthening of the B═B bond by 6.4 kcal/mol (for 2-PMe(3)), by 4.4 (for 2-PF(3)) and by 9.2 (for 2-PH(3)), when compared to a molecule developed on the experimental basis, 2-C(3)H(4)N(2) (ΔE(total) = -118.3 kcal/mol). The ETS scheme has shown that all contributions, that is, (i) orbital interaction ΔE(orb), (ii) Pauli repulsion ΔE(Pauli), and (iii) electrostatic stabilization ΔE(elstat), are important in determining the trend in the B═B bond energies, ΔE(total). ETS-NOCV results revealed that both σ(B═B) and π(B═B) contributions are responsible for the changes in ΔE(orb) values. All considered molecules of the type LB≡BL, 3-L, exhibit a stronger B≡B bond when compared to a double B═B connection in 2-L (|ΔE(total)| is lower by 11.8-42.5 kcal/mol, depending on the molecule). The main reason is a lower Pauli repulsion contribution noted for 3-CO, 3-PMe(3), and 3-PCl(3) molecules. In addition, in the case of 3-PMe(3) and 3-PCl(3), the orbital interaction term is more stabilizing; however, the effect is less pronounced compared to the drop in the Pauli repulsion term. In all of the systems with double and triple boron-boron bonds, the electronic factor (ΔE(orb)) dominates over the electrostatic contribution (ΔE(elstat)). Finally, the strongest B

  8. Teaching in Correctional Settings

    Science.gov (United States)

    de Koning, Mireille; Striedinger, Angelika

    2009-01-01

    In early 2009, Education International conducted a study amongst its member organisations on education in correctional settings in their respective countries. Findings reveal that education in correctional settings and the conditions of teachers working in them vary greatly between regions. Generally speaking, in most regions, but specifically in…

  9. Investigating the chemical and morphological evolution of GaAs capped InAs/InP quantum dots emitting at 1.5μm using aberration-corrected scanning transmission electron microscopy

    DEFF Research Database (Denmark)

    Kadkhodazadeh, Shima; Semenova, Elizaveta; Yvind, Kresten

    2011-01-01

    The emission wavelength of InAs quantum dots grown on InP has been shown to shift to the technologically desirable 1.5μm with the deposition of 1–2 monolayers of GaAs on top of the quantum dots. Here, we use aberration-corrected scanning transmission electron microscopy to investigate morphological...... and compositional changes occurring to the quantum dots as a result of the deposition of 1.7 monolayers of GaAs on top of them, prior to complete overgrowth with InP. The results are compared with theoretical models describing the overgrowth process....

  10. The Nature of the Interplay among Components of Pedagogical Content Knowledge in Reaction Rate and Chemical Equilibrium Topics of Novice and Experienced Chemistry Teachers

    Science.gov (United States)

    Akin, Fatma Nur; Uzuntiryaki-Kondakci, Esen

    2018-01-01

    We examined the interactions among pedagogical content knowledge (PCK) components of novice and experienced chemistry teachers in teaching reaction rate and chemical equilibrium topics in this qualitative multiple-case design study. For this aim, three chemistry teachers who had different levels of teaching experience in chemistry teaching were…

  11. FISICO: Fast Image SegmentatIon COrrection.

    Directory of Open Access Journals (Sweden)

    Waldo Valenzuela

    Full Text Available In clinical diagnosis, medical image segmentation plays a key role in the analysis of pathological regions. Despite advances in automatic and semi-automatic segmentation techniques, time-effective correction tools are commonly needed to improve segmentation results. Therefore, these tools must provide faster corrections with a lower number of interactions, and a user-independent solution to reduce the time frame between image acquisition and diagnosis.We present a new interactive method for correcting image segmentations. Our method provides 3D shape corrections through 2D interactions. This approach enables an intuitive and natural corrections of 3D segmentation results. The developed method has been implemented into a software tool and has been evaluated for the task of lumbar muscle and knee joint segmentations from MR images.Experimental results show that full segmentation corrections could be performed within an average correction time of 5.5±3.3 minutes and an average of 56.5±33.1 user interactions, while maintaining the quality of the final segmentation result within an average Dice coefficient of 0.92±0.02 for both anatomies. In addition, for users with different levels of expertise, our method yields a correction time and number of interaction decrease from 38±19.2 minutes to 6.4±4.3 minutes, and 339±157.1 to 67.7±39.6 interactions, respectively.

  12. Corrective camouflage in pediatric dermatology.

    Science.gov (United States)

    Tedeschi, Aurora; Dall'Oglio, Federica; Micali, Giuseppe; Schwartz, Robert A; Janniger, Camila K

    2007-02-01

    Many dermatologic diseases, including vitiligo and other pigmentary disorders, vascular malformations, acne, and disfiguring scars from surgery or trauma, can be distressing to pediatric patients and can cause psychological alterations such as depression, loss of self-esteem, deterioration of quality of life, emotional distress, and, in some cases, body dysmorphic disorder. Corrective camouflage can help cover cutaneous unaesthetic disorders using a variety of water-resistant and light to very opaque products that provide effective and natural coverage. These products also can serve as concealers during medical treatment or after surgical procedures before healing is complete. Between May 2001 and July 2003. corrective camouflage was used on 15 children and adolescents (age range, 7-16 years; mean age, 14 years). The majority of patients were girls. Six patients had acne vulgaris; 4 had vitiligo; 2 had Becker nevus; and 1 each had striae distensae, allergic contact dermatitis. and postsurgical scarring. Parents of all patients were satisfied with the cosmetic cover results. We consider corrective makeup to be a well-received and valid adjunctive therapy for use during traditional long-term treatment and as a therapeutic alternative in patients in whom conventional therapy is ineffective.

  13. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... can also invite bacteria that lead to gum disease. Click here to find out more. Who We ... can also invite bacteria that lead to gum disease. Click here to find out more. Corrective Jaw ...

  14. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... surgery, orthognathic surgery is performed to correct functional problems. Jaw Surgery can have a dramatic effect on ... without straining Chronic mouth breathing Sleep apnea (breathing problems when sleeping, including snoring) Your dentist, orthodontist and ...

  15. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... anesthesia, all forms of sedation and general anesthesia. Click here to find out more. Cleft Lip/Palate ... depending on the extent of the repair needed. Click here to find out more. Corrective Jaw Surgery ...

  16. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... for corrective jaw surgery: Difficulty chewing, or biting food Difficulty swallowing Chronic jaw or jaw joint (TMJ) ... a long-term commitment for you and your family, and will try to realistically estimate the time ...

  17. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... to correct a wide range of minor and major skeletal and dental irregularities, including the misalignment of ... including snoring) Your dentist, orthodontist and OMS will work together to determine whether you are a candidate ...

  18. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... find out more. Wisdom Teeth Management Wisdom Teeth Management An impacted ... and maxillofacial surgeon (OMS) to correct a wide range of minor and major skeletal and dental irregularities, ...

  19. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... Corrective Jaw Surgery Dental and Soft Tissue Surgery Dental Implant Surgery Facial Cosmetic Surgery Head, Neck and Oral Pathology Obstructive Sleep Apnea TMJ and Facial Pain Treatment of Facial Injury Wisdom Teeth Management Procedures ...

  20. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... It can also invite bacteria that lead to gum disease. Click here to find out more. Who We ... It can also invite bacteria that lead to gum disease. Click here to find out more. Corrective Jaw ...

  1. Corrective Action Investigation Plan for Corrective Action Unit 563: Septic Systems, Nevada Test Site, Nevada, with Errata Sheet, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Alfred Wickline

    2007-01-01

    Corrective Action Unit 563, Septic Systems, is located in Areas 3 and 12 of the Nevada Test Site, which is 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 563 is comprised of the four corrective action sites (CASs) below: • 03-04-02, Area 3 Subdock Septic Tank • 03-59-05, Area 3 Subdock Cesspool • 12-59-01, Drilling/Welding Shop Septic Tanks • 12-60-01, Drilling/Welding Shop Outfalls These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation (CAI) before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document.

  2. The use of natural abundance stable isotopic ratios to indicate the presence of oxygen-containing chemical linkages between cellulose and lignin in plant cell walls.

    Science.gov (United States)

    Zhou, Youping; Stuart-Williams, Hilary; Farquhar, Graham D; Hocart, Charles H

    2010-06-01

    Qualitative and quantitative understanding of the chemical linkages between the three major biochemical components (cellulose, hemicellulose and lignin) of plant cell walls is crucial to the understanding of cell wall structure. Although there is convincing evidence for chemical bonds between hemicellulose and lignin and the absence of chemical bonds between hemicellulose and cellulose, there is no conclusive evidence for the presence of covalent bonds between cellulose and lignin. This is caused by the lack of selectivity of current GC/MS-, NMR- and IR-based methods for lignin characterisation as none of these techniques directly targets the possible ester and ether linkages between lignin and cellulose. We modified the widely-accepted "standard" three-step extraction method for isolating cellulose from plants by changing the order of the steps for hemicellulose and lignin removal (solubilisation with concentrated NaOH and oxidation with acetic acid-containing NaClO(2), respectively) so that cellulose and lignin could be isolated with the possible chemical bonds between them intact. These linkages were then cleaved with NaClO(2) reagent in aqueous media of contrasting (18)O/(16)O ratios. We produced cellulose with higher purity (a lower level of residual hemicellulose and no detectable lignin) than that produced by the "standard" method. Oxidative artefacts may potentially be introduced at the lignin removal stage; but testing showed this to be minimal. Cellulose samples isolated from processing plant-derived cellulose-lignin mixtures in media of contrasting (18)O/(16)O ratios were compared to provide the first quantitative evidence for the presence of oxygen-containing ester and ether bonds between cellulose and lignin in Zea mays leaves. However, no conclusive evidence for the presence or lack of similar bonds in Araucaria cunninghamii wood was obtained. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. A method for the determination of the surface tension of cellulosic fibres in their natural state and its relation with chemical composition

    NARCIS (Netherlands)

    Hazendonk, van J.M.; Putten, van der I.C.; Keurentjes, J.T.F.

    1995-01-01

    The surface tensions of several natural cellulosic fibres like flax, hemp, kenaf and cotton and a synthetic cellulosic fibre have been determined using the so-called floating test. This method determines the liquid surface tension δF at which fibres placed on a liquid surface remain just floating.

  4. Antimycobacterial natural products from Moroccan medicinal plants: Chemical composition, bacteriostatic and bactericidal profile of Thymus satureioides and Mentha pulegium essential oils

    Directory of Open Access Journals (Sweden)

    Marwa Chraibi

    2016-10-01

    Conclusions: It is clearly evident from the results obtained that the Moroccan medicinal plants have great potential to be used as anti-tuberculosis agents. These findings may help scientists to undertake several research projects to discover useful natural product as new anti-tuberculosis drug.

  5. Agenesia isolada da artéria pulmonar direita ou esquerda: avaliação da evolução natural e a longo prazo, após intervenção corretiva Isolated unilateral pulmonary artery agenesis: evaluation of natural and long term evolution after corrective surgery

    Directory of Open Access Journals (Sweden)

    Edmar Atik

    2006-10-01

    hemoptysis in adults. Interventions such as pulmonary artery reconstruction and lobectomies were performed in 17% of the cases. We analyzed four of these cases, two in natural evolution and two with late term PH regression after surgical correction. METHODS: Three 22,10 and 35 month old male children and one 20 month old female child were included in the study. The 22 month old presented right-sided heart failure (RHF and cyanosis; the 10 month old presented RHF and the other two presented exertion fatigue. All had PH symptoms, right ventricular strain on the EKG and cardiomegaly. Cardiac catheterization showed systemic pressures in the contralateral pulmonary artery, with right-sided agenesis in three of the children and left-sided agenesis in one child. RESULTS: Surgical correction of pulmonary artery continuity was possible in the 22 month old and 10 month old using a 7mm diameter Goretex conduit between the pulmonary arteries up to the hypoplastic contralateral pulmonary hilum. There was early and late regression of the PH signs and the children remained stable during follow-up to the ages of 7 and 2.5 years, respectively. The pressure ratio between the left and right ventricles was 30 and 40%, in both cases. Pulmonary perfusion increased from 8 to 44% and from 8 to 23%, in the two cases. The same procedure was scheduled for the other patients. CONCLUSION: This technique has become the operation of choice for similar cases, that are rarely described in literature, even in the presence of severe PH and contralateral pulmonary artery hypoplasia.

  6. Relativistic Scott correction for atoms and molecules

    DEFF Research Database (Denmark)

    Solovej, Jan Philip; Sørensen, Thomas Østergaard; Spitzer, Wolfgang Ludwig

    2010-01-01

    We prove the first correction to the leading Thomas-Fermi energy for the ground state energy of atoms and molecules in a model where the kinetic energy of the electrons is treated relativistically. The leading Thomas-Fermi energy, established in [25], as well as the correction given here, are of ......We prove the first correction to the leading Thomas-Fermi energy for the ground state energy of atoms and molecules in a model where the kinetic energy of the electrons is treated relativistically. The leading Thomas-Fermi energy, established in [25], as well as the correction given here......, are of semiclassical nature. Our result on atoms and molecules is proved from a general semiclassical estimate for relativistic operators with potentials with Coulomb-like singularities. This semiclassical estimate is obtained using the coherent state calculus introduced in [36]. The paper contains a unified treatment...

  7. Accurate ab initio calculations of O-HO and O-H(-)O proton chemical shifts: towards elucidation of the nature of the hydrogen bond and prediction of hydrogen bond distances.

    Science.gov (United States)

    Siskos, Michael G; Tzakos, Andreas G; Gerothanassis, Ioannis P

    2015-09-07

    The inability to determine precisely the location of labile protons in X-ray molecular structures has been a key barrier to progress in many areas of molecular sciences. We report an approach for predicting hydrogen bond distances beyond the limits of X-ray crystallography based on accurate ab initio calculations of O-HO proton chemical shifts, using a combination of DFT and contactor-like polarizable continuum model (PCM). Very good linear correlation between experimental and computed (at the GIAO/B3LYP/6-311++G(2d,p) level of theory) chemical shifts were obtained with a large set of 43 compounds in CHCl3 exhibiting intramolecular O-HO and intermolecular and intramolecular ionic O-H(-)O hydrogen bonds. The calculated OH chemical shifts exhibit a strong linear dependence on the computed (O)HO hydrogen bond length, in the region of 1.24 to 1.85 Å, of -19.8 ppm Å(-1) and -20.49 ppm Å(-1) with optimization of the structures at the M06-2X/6-31+G(d) and B3LYP/6-31+G(d) level of theory, respectively. A Natural Bond Orbitals (NBO) analysis demonstrates a very good linear correlation between the calculated (1)H chemical shifts and (i) the second-order perturbation stabilization energies, corresponding to charge transfer between the oxygen lone pairs and σ antibonding orbital and (ii) Wiberg bond order of the O-HO and O-H(-)O hydrogen bond. Accurate ab initio calculations of O-HO and O-H(-)O (1)H chemical shifts can provide improved structural and electronic description of hydrogen bonding and a highly accurate measure of distances of short and strong hydrogen bonds.

  8. Comparison between physico-chemical properties of the technical Cashew Nut Shell Liquid (CNSL and those natural extracted from solvent and pressing

    Directory of Open Access Journals (Sweden)

    Francisco H. A Rodrigues

    2011-01-01

    Full Text Available Cashew nut shell liquid (CNSL is a by-product of the cashew kernel industry, applied mainly to produce polymeric derivatives. The technical CNSL (CNSLT was obtained industrially, extracted by roasting the cashew nut shells at temperatures between 180 and 200 ºC. Two methods were used to produce natural CNSL. For the extraction of CNSLNP, the cashew nut shells were pressed at room temperature. CNSLNS was extracted in hexane at room temperature and recovered at 50 ºC. A comparison was made of the composition determined by HPLC and properties generated by viscosity measurements and also by TG, DSC and IPDT (integral procedural decomposition temperature. Natural CNSLs displayed higher content of cardol and anacardic acid and lower percentage of cardanol than CNSLT. The higher content of cardanol in CNSLNS was the major difference between natural CNSLs. CNSLNP had higher levels of impurity, higher viscosity, lower thermoxidative stabilities and lower ebullition temperature. The CNSL obtained by cold solvent extraction and recovery at 50 ºC better preserves the original properties of the liquid.

  9. Fluid dynamics, particulate segregation, chemical processes, and natural ore analog discussions that relate to the potential for criticality in Hanford tanks

    Energy Technology Data Exchange (ETDEWEB)

    Barney, G.S.

    1996-09-27

    This report presents an in-depth review of the potential for nuclear criticality to occur in Hanford defense waste tanks during past, current and future safe storage and maintenance operations. The report also briefly discusses the potential impacts of proposed retrieval activities, although retrieval was not a main focus of scope. After thorough review of fluid dynamic aspects that focus on particle segregation, chemical aspects that focus on solubility and adsorption processes that might concentrate plutonium and/or separate plutonium from the neutron absorbers in the tank waste, and ore-body formation and mining operations, the interdisciplinary team has come to the conclusion that there is negligible risk of nuclear critically under existing storage conditions in Hanford site underground waste storage tanks. Further, for the accident scenarios considered an accidental criticality is incredible.

  10. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  11. Variation of Chemical Composition in Flowers and Leaves Essential Oils Among Natural Population of Tunisian Glebionis coronaria (L.) Tzvelev (Asteraceae).

    Science.gov (United States)

    Haouas, Dalila; Cioni, Pier Luigi; Flamini, Guido; Ben Halima-Kamel, Monia; Ben Hamouda, Mohamed Habib

    2016-10-01

    The aim of this study was to assess the percentage and constituents variations in flowers and leaves essential oil of three Glebionis coronaria (L.) Tzvelev population, growing wildly in three different ecotypes (Utique, M'saken, and Sahara Lektar) in Tunisia. The chemical compositions of these essential oils were analyzed by the GC and GC/MS systems. Qualitative and quantitative differences were recorded between essential oils extracted from plants collected from the three geographical provinces and between organs of the same plant (leaves and flowers). In fact, 161 components representing 87.2 - 96.5% of the whole oils were identified. Myrcene (3.2 - 35.7%), (Z)-β-ocimene (0.6 - 23.0%), camphor (0.6 - 17.2%), cis-chrysanthenol (0 - 6.9%), cis-chrysanthenyl acetate (1.1 - 17.9%), isobornyl acetate (1.6 - 3.5%), (E)-β-farnesene (0 - 6.0%), germacrene D (0 - 8.7%), and (E,E)-α-farnesene (0.7 - 12.4%) were the predominant components in the oils. These major constituents occur in different amounts depending on the organs (leaves or flowers) and the geographical origin of the plant. The chemotaxonomic usefulness of these data was discussed according to results of principal component analysis (PCA). The scores, together with the loadings, revealed a different chemical pattern for each population. © 2016 Wiley-VHCA AG, Zürich.

  12. Modulation of chemical dermal absorption by 14 natural products: a quantitative structure permeation analysis of components often found in topical preparations.

    Science.gov (United States)

    Muhammad, Faqir; Jaberi-Douraki, Majid; de Sousa, Damião Pergentino; Riviere, Jim E

    2017-09-01

    A large number of cosmetics and topical pharmaceuticals contain compounds of natural origin. There is a rising concern if these compounds can interact with the activity of other topically applied components in these formulations. The current study demonstrates modulation of dermal absorption of model components often found in topical preparations (14C caffeine and 14C salicylic acid) by a set of 14 compounds of natural origin using a flow through in vitro porcine skin diffusion system. The parameters of flux and permeability were calculated and quantitative structure permeation relationship (QSPR) analysis conducted on different molecular descriptors of modulator compounds. Terpinyl acetate was the greatest permeability/flux enhancer for caffeine followed by s-perillyl acetate and limonene 1,2-epoxide. The permeability/flux of salicylic acid was highest with hydroxycitronellal followed by limonene 1,2-epoxide and s-perillyl acetate. The optimum descriptors using stepwise regression analysis for predicting additive modulation on penetrant permeability/flux were polar surface area, log P for caffeine and Henry's Law constant, number of freely rotatable bonds, and water solubility for salicylic acid. In parallel with the experimental techniques, a novel mathematical model was developed to estimate the permeability coefficients and improve the stepwise regression analysis for assessing modulator effects. The r2 values significantly increased for multicomponent QSPR models. Notably, limonene 1,2-epoxide and s-perillyl acetate were excellent enhancers for both caffeine and salicylic acid. These results confirm that some natural products incorporated into topical formulations will enhance absorption of other components which could affect their safety and efficacy profiles.

  13. Deciphering the "chemical" nature of the exotic isotopes of hydrogen by the MC-QTAIM analysis: the positively charged muon and the muonic helium as new members of the periodic table.

    Science.gov (United States)

    Goli, Mohammad; Shahbazian, Shant

    2014-04-14

    This report is a primarily survey on the chemical nature of some exotic species containing the positively charged muon and the muonic helium, i.e., the negatively charged muon plus helium nucleus, as exotic isotopes of hydrogen, using the newly developed multi-component quantum theory of atoms in molecules (MC-QTAIM) analysis, employing ab initio non-Born-Oppenhiemer wavefunctions. Accordingly, the "atoms in molecules" analysis performed on various asymmetric exotic isotopomers of the hydrogen molecule, recently detected experimentally [Science, 2011, 331, 448], demonstrates that both the exotic isotopes are capable of forming atoms in molecules and retaining the identity of hydrogen atoms. Various derived properties of atomic basins containing the muonic helium cast no doubt that apart from its short life time, it is a heavier isotope of hydrogen while the properties of basins containing the positively charged muon are more remote from those of the orthodox hydrogen basins, capable of appreciable donation of electrons as well as large charge polarization. However, with some tolerance, they may also be categorized as hydrogen basins though with a smaller electronegativity. All in all, the present study also clearly demonstrates that the MC-QTAIM analysis is an efficient approach to decipher the chemical nature of species containing exotic constituents, which are difficult to elucidate by experimental and/or alternative theoretical schemes.

  14. Microorganisms and Chemical Pollution

    Science.gov (United States)

    Alexander, M.

    1973-01-01

    Discusses the importance of microorganisms in chemical pollution and pollution abatement. Selected chemical pollutants are chosen to illustrate that microorganisms synthesize hazardous substances from reasonably innocuous precursors, while others act as excellent environmental decontaminating agents by removing undesirable natural and synthetic…

  15. Model Correction Factor Method

    DEFF Research Database (Denmark)

    Christensen, Claus; Randrup-Thomsen, Søren; Morsing Johannesen, Johannes

    1997-01-01

    The model correction factor method is proposed as an alternative to traditional polynomial based response surface techniques in structural reliability considering a computationally time consuming limit state procedure as a 'black box'. The class of polynomial functions is replaced by a limit stat...

  16. Correction to ATel 10681

    Science.gov (United States)

    Wang, Xiaofeng

    2017-08-01

    We report a correction to the spectroscopic classification of two optical transients announced in ATel #10681. In the main text of the telegram, SN 2017giq and MASTER OT J033744.97+723159.0 should be classified as type Ic and type IIb supernovae, respectively, which were reversed in the original report. We apologize for any confusion caused by this typo error.

  17. Corrective Jaw Surgery

    Medline Plus

    Full Text Available ... can also invite bacteria that lead to gum disease. Click here to find out more. Who We Are Find a Surgeon News Videos Contact Administration of Anesthesia Cleft Lip/Palate and Craniofacial Surgery Corrective Jaw Surgery Dental and Soft Tissue Surgery Dental Implant Surgery Facial ...

  18. Error Correcting Codes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 10. Error Correcting Codes How Numbers Protect Themselves. Priti Shankar. Series Article Volume 1 ... Author Affiliations. Priti Shankar1. Department of Computer Science and Automation, Indian Institute of Science, Bangalore 560 012, India ...

  19. Error Correcting Codes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 3. Error Correcting Codes - Reed Solomon Codes. Priti Shankar. Series Article Volume 2 Issue 3 March 1997 pp 33-47. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/03/0033-0047 ...

  20. Text Induced Spelling Correction

    NARCIS (Netherlands)

    Reynaert, M.W.C.

    2004-01-01

    We present TISC, a language-independent and context-sensitive spelling checking and correction system designed to facilitate the automatic removal of non-word spelling errors in large corpora. Its lexicon is derived from a very large corpus of raw text, without supervision, and contains word

  1. Correctness of concurrent processes

    NARCIS (Netherlands)

    E.R. Olderog (Ernst-Rüdiger)

    1989-01-01

    textabstractA new notion of correctness for concurrent processes is introduced and investigated. It is a relationship P sat S between process terms P built up from operators of CCS [Mi 80], CSP [Ho 85] and COSY [LTS 79] and logical formulas S specifying sets of finite communication sequences as in

  2. 10. Correctness of Programs

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 4. Algorithms - Correctness of Programs. R K Shyamasundar. Series Article Volume 3 ... Author Affiliations. R K Shyamasundar1. Computer Science Group, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India.

  3. Refraction corrections for surveying

    Science.gov (United States)

    Lear, W. M.

    1980-01-01

    Optical measurements of range and elevation angles are distorted by refraction of Earth's atmosphere. Theoretical discussion of effect, along with equations for determining exact range and elevation corrections, is presented in report. Potentially useful in optical site surveying and related applications, analysis is easily programmed on pocket calculator. Input to equation is measured range and measured elevation; output is true range and true elevation.

  4. Error Correcting Codes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 1. Error Correcting Codes The Hamming Codes. Priti Shankar. Series Article Volume 2 Issue 1 January ... Author Affiliations. Priti Shankar1. Department of Computer Science and Automation, Indian Institute of Science, Bangalore 560 012, India ...

  5. Issues in Correctional Training and Casework. Correctional Monograph.

    Science.gov (United States)

    Wolford, Bruce I., Ed.; Lawrenz, Pam, Ed.

    The eight papers contained in this monograph were drawn from two national meetings on correctional training and casework. Titles and authors are: "The Challenge of Professionalism in Correctional Training" (Michael J. Gilbert); "A New Perspective in Correctional Training" (Jack Lewis); "Reasonable Expectations in Correctional Officer Training:…

  6. Accumulation of Dechlorane Plus flame retardant in terrestrial passerines from a nature reserve in South China: the influences of biological and chemical variables.

    Science.gov (United States)

    Peng, Ying; Wu, Jiang-Ping; Tao, Lin; Mo, Ling; Zheng, Xiao-Bo; Tang, Bin; Luo, Xiao-Jun; Mai, Bi-Xian

    2015-05-01

    Although a number of studies have addressed the bioaccumulation of Dechlorane Plus (DP) flame retardant in wildlife, few data are available on terrestrial organisms. This study examined the presence of DP isomers in the muscle tissue of seven terrestrial resident passerine species, i.e., the great tit (Parus major), the oriental magpie-robin (Copsychus saularis), the red-whiskered bulbul (Pycnonotus jocosus), the light-vented bulbul (Pycnonotus sinensis), the streak-breasted scimitar babbler (Pomatorhinus ruficollis), the long-tailed shrike (Lanius schach), and the orange-headed thrush (Zoothera citrina), from a national nature reserve located in South China. The ∑DP (sum of syn-DP and anti-DP) concentrations ranged from 1.2 to 104 ng/g lipid weight, with significantly higher levels in insectivorous birds than in omnivorous birds. The overall exposure to DP isomers of the current passerines may be attributed to the intensive release of this pollutant from electronic waste recycling sites and industrial zones in the vicinity of the nature reserve. Species-specific DP isomeric profiles were also found, with significantly greater fanti values (the isomer fractions of anti-DP) in the red-whiskered bulbul and the oriental magpie-robin. Additionally, the fanti values were significantly negatively correlated to ∑DP concentrations for the individual bird samples, suggesting the influence of DP concentrations on the isomeric profiles. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Structural confirmation, single X-ray crystallographic behavior, molecular docking and other physico-chemical properties of gerberinol, a natural dimethyl dicoumarol from Gerbera lanuginosa Benth. (Compositae)

    Science.gov (United States)

    Brahmachari, Goutam; Das, Saktipada; Kumar, Abhishek; Misra, Neeraj; Sharma, Sakshi; Gupta, Vivek K.

    2017-05-01

    The proposed structure of gerberinol (1), a naturally occurring dimethyl dicoumarol, has been conclusively established on the basis of its detailed spectral and single crystal X-ray analyses. The compound, C21H16O6, crystallizes in the monoclinic space group P21/c with the following unit-cell parameters: a = 14.0884(14), b = 15.1746(15), c = 7.6392(8)Å, α = 90.00°, β = 98.949(4)°, γ = 90.00° and Z = 4. The crystal structure was solved by direct methods using single-crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R-value of 11.43 for 2377 observed reflections. Exhaustive theoretical studies on the molecular structure, vibrational spectra, HOMO, LUMO, MESP surfaces, and molecular docking of this plant-derived natural molecule have also been performed. The equilibrium geometry of the title compound has been obtained and analyzed using DFT-B3LYP/6-311 + G(d,p) method. Molecular docking study of the molecule for predicting its possible biological activities revealed that the compound might be a potent antimicrobial, neurodegenerative and anticancer agent as evidenced from its excellent FF (full fitness) score for 1FUJ and 1ZX1 enzymes.

  8. Inflation from nilpotent Kaehler corrections

    Energy Technology Data Exchange (ETDEWEB)

    McDonough, Evan [McGill Univ. Montreal, QC (Canada); Scalisi, Marco [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2016-09-15

    We develop a new class of supergravity cosmological models where inflation is induced by terms in the Kaehler potential which mix a nilpotent superfield S with a chiral sector Φ. As the new terms are non-(anti)holomorphic, and hence cannot be removed by a Kaehler transformation, these models are intrinsically Kaehler potential driven. Such terms could arise for example due to a backreaction of an anti-D3 brane on the string theory bulk geometry. We show that this mechanism is very general and allows for a unified description of inflation and dark energy, with controllable SUSY breaking at the vacuum. When the internal geometry of the bulk field is hyperbolic, we prove that small perturbative Kaehler corrections naturally lead to α-attractor behaviour, with inflationary predictions in excellent agreement with the latest Planck data.

  9. A theory for the origin of a self-replicating chemical system. I - Natural selection of the autogen from short, random oligomers

    Science.gov (United States)

    White, D. H.

    1980-01-01

    A general theory is presented for the origin of a self-replicating chemical system, termed an autogen, which is capable of both crude replication and translation (protein synthesis). The theory requires the availability of free energy and monomers to the system, a significant background low-yield synthesis of kinetically stable oligopeptides and oligonucleotides, the localization of the oligomers, crude oligonucleotide selectivity of amino acids during oligopeptide synthesis, crude oligonucleotide replication, and two short peptide families which catalyze replication and translation, to produce a localized group of at least one copy each of two protogenes and two protoenzymes. The model posits a process of random oligomerization, followed by the random nucleation of functional components and the rapid autocatalytic growth of the functioning autogen to macroscopic amounts, to account for the origin of the first self-replicating system. Such a process contains steps of such high probability and short time periods that it is suggested that the emergence of an autogen in a laboratory experiment of reasonable time scale may be possible.

  10. Accumulation of Dechlorane Plus flame retardant in terrestrial passerines from a nature reserve in South China: The influences of biological and chemical variables

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Ying [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Wu, Jiang-Ping, E-mail: jpwu@gig.ac.cn [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Tao, Lin [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Mo, Ling [Hainan Research Academy of Environmental Sciences, Haikou 571126 (China); Zheng, Xiao-Bo; Tang, Bin [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Luo, Xiao-Jun; Mai, Bi-Xian [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2015-05-01

    Although a number of studies have addressed the bioaccumulation of Dechlorane Plus (DP) flame retardant in wildlife, few data are available on terrestrial organisms. This study examined the presence of DP isomers in the muscle tissue of seven terrestrial resident passerine species, i.e., the great tit (Parus major), the oriental magpie-robin (Copsychus saularis), the red-whiskered bulbul (Pycnonotus jocosus), the light-vented bulbul (Pycnonotus sinensis), the streak-breasted scimitar babbler (Pomatorhinus ruficollis), the long-tailed shrike (Lanius schach), and the orange-headed thrush (Zoothera citrina), from a national nature reserve located in South China. The ∑DP (sum of syn-DP and anti-DP) concentrations ranged from 1.2 to 104 ng/g lipid weight, with significantly higher levels in insectivorous birds than in omnivorous birds. The overall exposure to DP isomers of the current passerines may be attributed to the intensive release of this pollutant from electronic waste recycling sites and industrial zones in the vicinity of the nature reserve. Species-specific DP isomeric profiles were also found, with significantly greater f{sub anti} values (the isomer fractions of anti-DP) in the red-whiskered bulbul and the oriental magpie-robin. Additionally, the f{sub anti} values were significantly negatively correlated to ∑DP concentrations for the individual bird samples, suggesting the influence of DP concentrations on the isomeric profiles. - Highlights: • We investigated the occurrence of DP in seven species of terrestrial passerines. • Insectivorous birds accumulated higher ∑DP concentrations than omnivorous birds. • Inter-species differences in the f{sub anti} values were observed. • The f{sub anti} values were significantly correlated to DP concentrations.

  11. 75 FR 17055 - Gray's Reef National Marine Sanctuary Regulations on the Use of Spearfishing Gear; Correction

    Science.gov (United States)

    2010-04-05

    ... notice corrects the grammatical error in Part 922.92 (a)(11)(iii) by adding the word ``it'' to the... requirements because it is unnecessary. This rule corrects a grammatical error in the regulations that does not... necessary due to the minimal nature of the correcting amendment. This rule corrects a grammatical error in...

  12. A comprehensive study of the toxicity of natural multi-contaminated sediments: New insights brought by the use of a combined approach using the medaka embryo-larval assay and physico-chemical analyses.

    Science.gov (United States)

    Barjhoux, Iris; Clérandeau, Christelle; Menach, Karyn Le; Anschutz, Pierre; Gonzalez, Patrice; Budzinski, Hélène; Morin, Bénédicte; Baudrimont, Magalie; Cachot, Jérôme

    2017-08-01

    Sediment compartment is a long term sink for pollutants and a secondary source of contamination for aquatic species. The abiotic factors controlling the bioavailability and thus the toxicity of complex mixtures of pollutants accumulated in sediments are poorly documented. To highlight the different factors influencing sediment toxicity, we identified and analyzed the physico-chemical properties, micro-pollutant contents, and toxicity level of six contrasted sediments in the Lot-Garonne continuum. Sediment toxicity was evaluated using the recently described Japanese medaka (Oryzias latipes) embryo-larval assay with direct exposure to whole sediment (MELAc). Multiple toxicity endpoints including embryotoxicity, developmental defects and DNA damage were analyzed in exposed embryos. Chemical analyses revealed significant variations in the nature and contamination profile of sediments, mainly impacted by metallic trace elements and, unexpectedly, polycyclic aromatic hydrocarbons. Exposure to sediments induced different toxic impacts on medaka early life stages when compared with the reference site. Principal component analysis showed that the toxic responses following exposure to sediments from the Lot River and its tributary were associated with micro-pollutant contamination: biometric measurements, hatching success, genotoxicity, craniofacial deformities and yolk sac malabsorption were specifically correlated to metallic and organic contaminants. Conversely, the main biological responses following exposure to the Garonne River sediments were more likely related to their physico-chemical properties than to their contamination level. Time to hatch, cardiovascular injuries and spinal deformities were correlated to organic matter content, fine particles and dissolved oxygen levels. These results emphasize the necessity of combining physico-chemical analysis of sediment with toxicity assessment to accurately evaluate the environmental risks associated with sediment

  13. Biossorção de cobre utilizando-se o mesocarpo e o endocarpo da macadâmia natural e quimicamente tratados Biosorption of copper using the mesocarp and endocarp of natural and chemically treated macadamia

    Directory of Open Access Journals (Sweden)

    Naiza V. Boas

    2012-12-01

    Full Text Available Objetivou-se, neste trabalho, analisar a eficiência de resíduos de macadâmia (mesocarpo e endocarpo com e sem modificações químicas na biossorção de íons cobre II. As modificações químicas no biossorvente foram realizadas com hidróxido de sódio (NaOH e com NaOH mais ácido cítrico e comprovadas por espectroscopia na região do infravermelho, pela presença dos picos em 1710 e 1420 cm-1 como também pela microscopia eletrônica de varredura (MEV observando-se aumento da rugosidade na superfície. Os melhores resultados de biossorção foram para o mesocarpo modificado com NaOH, em pH igual a 5. O tempo de equilíbrio adsorvente-adsorbato foi de 140 min; além disto, o sistema seguiu um modelo cinético de pseudo-segunda ordem e a capacidade máxima de biossorção foi de 28,82 mg g-1. As isotermas para os resíduos modificados com NaOH seguiram o modelo de Langmuir e as modificadas com ácido se ajustaram ao modelo de Freundlich. Constatou-se que o processo de biossorção foi espontâneo energeticamente devido aos valores negativos para a energia de Gibbs. Comprovou-se, então, que o adsorvente possui alta capacidade de dessorção; assim, este material poderá ser novamente reutilizado; portanto, este resíduo poderá, futuramente equipar, filtros para remoção de Cu2+.The objective was to analyze the efficiency of macadamia waste with and without chemical changes in biosorption of copper II (Cu2+. The chemical changes in the biosorbent with sodium hydroxide (NaOH and with NaOH and citric acid were evidenced by infrared spectroscopy by the appearance of peaks in 1710 and 1420 cm-1 and by scanning electron microscopy, observed an increase of roughness on the surface. The best results of the adsorption were observed in mesocarp modified with NaOH, in pH equal to 5. An equilibrium time adsorbent - adsorbate was 140 min, in addition, the system followed a kinetic model of pseudo-second order and the maximum adsorption capacity was

  14. Correction of refractive errors

    Directory of Open Access Journals (Sweden)

    Vladimir Pfeifer

    2005-10-01

    Full Text Available Background: Spectacles and contact lenses are the most frequently used, the safest and the cheapest way to correct refractive errors. The development of keratorefractive surgery has brought new opportunities for correction of refractive errors in patients who have the need to be less dependent of spectacles or contact lenses. Until recently, RK was the most commonly performed refractive procedure for nearsighted patients.Conclusions: The introduction of excimer laser in refractive surgery has given the new opportunities of remodelling the cornea. The laser energy can be delivered on the stromal surface like in PRK or deeper on the corneal stroma by means of lamellar surgery. In LASIK flap is created with microkeratome in LASEK with ethanol and in epi-LASIK the ultra thin flap is created mechanically.

  15. Hydro-chemical detection of permafrost degradation in the Eastern European Alps - Implications for geomorphological process studies and natural hazard assessment

    Science.gov (United States)

    Kraushaar, Sabine; Kamleitner, Sarah; Czarnowsky, Verena; Blöthe, Jan; Morche, David; Knöller, Kay; Lachner, Johannes

    2017-04-01

    The Gepatschferner glacier in the Upper Kaunertal valley is one of the fastest melting glaciers in the Eastern European Alps. With a retreat rate of around 110 m a-1 since the hydrological year 2012/ 2013, unconsolidated sediments of steep lateral moraines have been exposed to erosion, from which nowadays episodic and perennial springs well. We hypothesize that the springs indicate the melt out of dead ice lenses in areas below 2500 m, causing a potential significant morphological change in the moraines and a decrease of slope stability in the proglacial long after glacier retreat. However, permafrost degradation has not been considered so far in contemporary erosion measurements. The present study aims to identify the spring water's origin and displays first attempts of quantifying thermal erosion, which describes the matrix volume loss due to melting and drainage of ice water. Samples were routinely analyzed for temperature, electrical conductivity, δ2H, and δ18O. Results support the hypothesis that certain springs derive from melting ice of similar isotopic signature as the glacier. In a second step, chosen samples were examined for the long-lived anthropogenic nuclide 129I. Since the 1950s the atmospheric abundance of 129I has significantly increased. Its occurrence in the water samples hints a surface contact of the waters in the last 65 years. Springs of ice origin show little 129I content and are believed to derive from dead ice by the glacier. First electric resistivity measurements support the hydro-chemical results and suggest the existence of ice lenses in the subsurface. Ice ablation and discharge measurements allowed first estimates of the thermal erosion volume caused by the melt out and drainage of ice lenses.

  16. Predicting autoignition characteristics of premixed natural gas mixture under lean conditions by using a detailed chemical kinetics model; Kagaku hanno sokudoron wo koryoshita tennen gas kihaku yokongoki no jiko chakka tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, T.; Ikeda, T.; Kusaka, J.; Daisho, Y. [Waseda University, Tokyo (Japan)

    1998-10-15

    Study was made on autoignition characteristics of natural gas by using a detailed chemical kinetics model. An engine is being watched which is featured by autoignition by compressing homogeneous lean premixture of air and natural gas as clean alternative fuel. However, because natural gas is composed of major methane, and minor ethane, propane and butane, autoignition is difficult, while rapid pressure rise is predicted at autoignition. Intake temperature rise and compression ratio rise bring autoignition timing forward by rising temperature in a cylinder. The effect of an air excess ratio on ignition timing and autoignition region is small under constant intake pressure and smaller air excess ratios, because of the negation between an effect bringing ignition timing forward by increase in fuel concentration and an effect delaying ignition timing by increase in polyatomic molecules in the premixture. Since combustion starts from n-butane, ignition timing is delayed with an increase in methane ratio. Although the feasibility of compressive ignition combustion using the lean premixture was confirmed, measures against excess pressure rise rates are necessary. 7 refs., 8 figs., 3 tabs.

  17. 'Pharmaceutical and chemical personal care products determination in natural and residual waters; Determinaciond e farmacos y productos quimicos de cuidado personal (PPcps) en aguas naturales y residuales

    Energy Technology Data Exchange (ETDEWEB)

    Jordi, R.; Gomez, M.; Vazquez, M. J.

    2004-07-01

    A quantitative, selected and sensitive method on liquid-liquid extraction (LLE)coupled to analysis by gas chromatography/mass spectrometry (GC/MS) is described for analysis of a selected group of chemicals compounds used as pharmaceuticals and personal care products (PPcPs). They are considered as persistent-emergent pollutants in natural and residual waters. The studied PPCPs- ibuprofen, diclofenac, benzafibrate, diazepan, carbamazepine, galaxolide, tonalide, celestolide, traseolide and cashmeran-are representative for three categories of PPCPs: acids and neutrals pahrmaceuticals and polycyclic synthetic musk, all of them with wide use. The effectiveness of the proposed method was higher than 90% in three different matrix, quantification limits, were at order of ng/L range. The estimated uncertainty was about 23% for all compounds. to asses the performance of the method, natural and wastewaters were analyzed. the obtained results showed that galaxolide, tonalide, ibuprofen, benzafibrate are the most frequently PPCP identified in these waters. Currently, concentrations found in the wastewater are ten times higher than those found in natural waters. No PPCP or very low concentrations were found in the tap water samples analyzed. (Author) 13 refs.

  18. [Correct contact lens hygiene].

    Science.gov (United States)

    Blümle, S; Kaercher, T; Khaireddin, R

    2013-06-01

    Although contact lenses have long been established in ophthalmology, practical aspects of handling contact lenses is becoming increasingly less important in the clinical training as specialist for ophthalmology. Simultaneously, for many reasons injuries due to wearing contact lenses are increasing. In order to correct this discrepancy, information on contact lenses and practical experience with them must be substantially increased from a medical perspective. This review article deals with the most important aspects for prevention of complications, i.e. contact lens hygiene.

  19. Studies on chemical structure modification and biology of a natural product, gambogic acid (I): Synthesis and biological evaluation of oxidized analogues of gambogic acid.

    Science.gov (United States)

    Wang, Jinxin; Zhao, Li; Hu, Yang; Guo, Qinglong; Zhang, Lei; Wang, Xiaojian; Li, Nianguang; You, Qidong

    2009-06-01

    Gambogic acid (GA), a natural product, exhibits high potency in inhibiting cancer cell growth through the effective induction of apoptosis. In order to investigate the structure-activity relationships of GA derivatives, 11 oxidized derivatives of GA were synthesized. Some of them showed strong inhibitory effects on HT-29, Bel-7402, BGC-823, A549, and SKOV 3 cell lines. Moreover, in this paper the cellular growth inhibitor 39-hydroxy-6-methoxy-gambogic acid methyl ester (10) was identified as a HepG2 cell apoptosis inhibitor through Annexin-V/PI double staining assay and the expression of the related apoptotic proteins (Bax and Bcl-2). Compound 10 may serve as a potential lead compound for the development of new anticancer drugs. Further SAR studies of GA derivatives indicated that modification of carbon-carbon double bond at C-32/33 or C-37/38 and of the methyl groups at C-39/C-35 can improve antitumor activity.

  20. Effect of different drying techniques on flowability characteristics and chemical properties of natural carbohydrate-protein Gum from durian fruit seed

    Directory of Open Access Journals (Sweden)

    Mirhosseini Hamed

    2013-01-01

    Full Text Available Abstract Background A natural carbohydrate biopolymer was extracted from the agricultural biomass waste (durian seed. Subsequently, the crude biopolymer was purified by using the saturated barium hydroxide to minimize the impurities. Finally, the effect of different drying techniques on the flow characteristics and functional properties of the purified biopolymer was investigated. The present study elucidated the main functional characteristics such as flow characteristics, water- and oil-holding capacity, solubility, and foaming capacity. Results In most cases except for oven drying, the bulk density decreased, thus increasing the porosity. This might be attributed to the increase in the inter-particle voids of smaller sized particles with larger contact surface areas per unit volume. The current study revealed that oven-dried gum and freeze-dried gum had the highest and lowest compressibility index, thus indicating the weakest and strongest flowability among all samples. In the present work, the freeze-dried gum showed the lowest angle of repose, bulk, tapped and true density. This indicates the highest porosity degree of freeze dried gum among dried seed gums. It also exhibited the highest solubility, and foaming capacity thus providing the most desirable functional properties and flow characteristics among all drying techniques. Conclusion The present study revealed that freeze drying among all drying techniques provided the most desirable functional properties and flow characteristics for durian seed gum.

  1. Taking advantage of natural gas for the energy and fuel supply for the Brazilian energy intensive industries: aluminium, siderurgy and chemical products; O aproveitamento do gas natural para o suprimento de energia e combustivel para as industrias energointensivas brasileiras: aluminio, siderurgia e produtos quimicos

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Jose Fernando Leme [Universidade Sao Paulo (USP), SP (Brazil). Programa Interunidades de Pos Graduacao em Energia]. E-mail: romero@iee.usp.br

    2006-07-01

    This work intend to analyse natural gas success in the energy generation for siderurgy industry, aluminium and basic organic chemical products. There is a necessity to inform economy-policy and the energy policy relationship, showing the Brazilian State actuation in the economic development mechanism and electric energy supply. Cast iron and iron, metals and no-irons are considered as electric intensives and energy intensives industry activities. These are sectors that produce merchandises for exportation and spend many quantities of electrical energy for each produced physical unity of law aggregate economic value. (author)

  2. Youth in Colleges and in Corrections: Institutional Influences

    Science.gov (United States)

    Newcomb, Theodore M.

    1978-01-01

    Findings concerning characteristics of recently arrived youth and of longtimers in colleges and in correctional institutions are compared. It is noted that coercion both on entering a correctional institution and thereafter, has much to do with the nature and degree of peer influence therin. (Author/AM)

  3. Repeated applications of compost and manure mainly affect the size and chemical nature of particulate organic matter in a loamy soil after 8 years

    Science.gov (United States)

    Peltre, Clement; Dignac, Marie-France; Doublet, Jeremy; Plante, Alain; Houot, Sabine

    2013-04-01

    Land application of exogenous organic matter (EOM) of residual origin can help to maintain or increase soil organic carbon (SOC) stocks. However, it remains necessary to quantify and predict the soil C accumulation and to determine under which form the C accumulates. Changes to the chemical composition of soil organic matter (SOM) after repeated applications of composts and farmyard manure were investigated in a field experiment (Qualiagro experiment, Ile-de-France) after 8 years of applications of green waste and sludge compost (GWS), municipal solid waste compost (MSW), biowaste compost (BIOW) or farmyard manure (FYM). The soil was fractionated into particulate organic matter >50 µm (POM), a heavy fraction >50 µm and a 0-50 µm fraction demineralized with hydrofluoric acid (HF). Repeated EOM applications significantly increased total SOC stocks, the C amount in the POM fraction and to a less extent in the 0-50 µm fraction compared to the reference treatment. Compost applications accumulated C preferentially under the form of coarse organic matter of size >50 µm, whereas the FYM accumulated similar C proportions of size >50 µm and 0-50 µm, which was attributed to the presence in the FYM of a fraction of labile C stimulating microbial activity and producing humified by-products together with a fraction of stabilized C directly alimenting the humified fraction of SOC. Pyrolysis-GC/MS and DRIFT spectroscopy revealed enrichment in lignin in the POM fractions of amended soils with GWS, BIOW and FYM. In the soil receiving MSW compost, the pyrolysate of the POM fraction revealed the presence of plastics originating from the MSW compost. A lower C mineralization during laboratory incubation was found for the POM fractions of amended soils compared with the POM from reference soil. This feature was related to a lower ratio of (furfural+acetic acid) / pyrole pyrolysis products in POM of amended vs. reference plots, indicating a higher degree of recalcitrance.. The POM

  4. The Nature of the Chemical Process. 1. Symmetry Evolution – Revised Information Theory, Similarity Principle and Ugly Symmetry

    Directory of Open Access Journals (Sweden)

    Shu-Kun Lin

    2001-03-01

    Full Text Available Abstract: Symmetry is a measure of indistinguishability. Similarity is a continuous measure of imperfect symmetry. Lewis' remark that “gain of entropy means loss of information” defines the relationship of entropy and information. Three laws of information theory have been proposed. Labeling by introducing nonsymmetry and formatting by introducing symmetry are defined. The function L ( L=lnw, w is the number of microstates, or the sum of entropy and information, L=S+I of the universe is a constant (the first law of information theory. The entropy S of the universe tends toward a maximum (the second law law of information theory. For a perfect symmetric static structure, the information is zero and the static entropy is the maximum (the third law law of information theory. Based on the Gibbs inequality and the second law of the revised information theory we have proved the similarity principle (a continuous higher similarity−higher entropy relation after the rejection of the Gibbs paradox and proved the Curie-Rosen symmetry principle (a higher symmetry−higher stability relation as a special case of the similarity principle. The principles of information minimization and potential energy minimization are compared. Entropy is the degree of symmetry and information is the degree of nonsymmetry. There are two kinds of symmetries: dynamic and static symmetries. Any kind of symmetry will define an entropy and, corresponding to the dynamic and static symmetries, there are static entropy and dynamic entropy. Entropy in thermodynamics is a special kind of dynamic entropy. Any spontaneous process will evolve towards the highest possible symmetry, either dynamic or static or both. Therefore the revised information theory can be applied to characterizing all kinds of structural stability and process spontaneity. Some examples in chemical physics have been given. Spontaneous processes of all kinds of molecular

  5. Transition-state theory and dynamical corrections

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Hansen, Flemming Yssing

    2002-01-01

    . The correction factor due to non-adiabatic dynamics is considered in relation to the non-activated dissociative sticking of N-2 on Fe(111). For this process, conventional transition-state theory gives a sticking probability which is about 10 times too large (at T = 300 K). We estimate that the sticking......We consider conventional transition-state theory, and show how quantum dynamical correction factors can be incorporated in a simple fashion, as a natural extension of the fundamental formulation. Corrections due to tunneling and non-adiabatic dynamics are discussed, with emphasis on the latter...... probability is reduced by a factor of 2 due to non-adiabatic dynamics....

  6. Análise química de pigmentos minerais naturais de Itabirito (MG Chemical analysis on natural mineral pigments from Itabirito (MG

    Directory of Open Access Journals (Sweden)

    A. R. P. Pereira

    2007-03-01

    Full Text Available Este trabalho tem o propósito de estudar composições e aplicações de pigmentos de Minas Gerais. Foi realizado um estudo qualitativo e quantitativo de pigmentos naturais coletados na região de Itabirito. As amostras foram denominadas segundo o Sistema Munsell de Cores e apresentaram composições variadas. Os minerais identificados por difração de raios X e confirmados por microscopia eletrônica de varredura (MEV foram a caulinita, ilita, talco e hematita, característicos da região. Análises de espectroscopia dispersiva de energia (EDS produziram resultados semi-quantitativos dos elementos presentes. A termogravimetria indicou pequena perda de massa, referente à umidade das amostras. A análise térmica diferencial indicou uma quantidade maior de caulinita no pigmento vermelho em relação aos demais. O teor de ferro presente nas amostras foi determinado por análise volumétrica e por espectrofotometria por absorção molecular na região do ultravioleta-visível. Os pigmentos apresentaram boa estabilidade térmica indicando a sua potencialidade de aplicação em peças cerâmicas.This work has the purpose of studying compositions and applications of natural pigments found in Minas Gerais. A qualitative and quantitative study of some pigments collected in the region of Itabirito was carried out. The samples were named according to Munsell Color System and presented a variety of compositions. The minerals identified by X-ray diffraction and confirmed by scanning electronic microscopy (SEM were kaolinite, illite, talc and hematite, characteristic from this region. Analyses by energy dispersive spectroscopy (EDS produced semi-quantitative results of the elements present in the samples. Thermogravimetry indicated small weight loss referring to the humidity of the samples. Differential thermal analysis indicated a large amount of kaolinite in the red pigment when compared with the others. The iron content presents in the samples was

  7. Brain Image Motion Correction

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Benjaminsen, Claus; Larsen, Rasmus

    2015-01-01

    The application of motion tracking is wide, including: industrial production lines, motion interaction in gaming, computer-aided surgery and motion correction in medical brain imaging. Several devices for motion tracking exist using a variety of different methodologies. In order to use such devices...... offset and tracking noise in medical brain imaging. The data are generated from a phantom mounted on a rotary stage and have been collected using a Siemens High Resolution Research Tomograph for positron emission tomography. During acquisition the phantom was tracked with our latest tracking prototype...

  8. Turbulence compressibility corrections

    Science.gov (United States)

    Coakley, T. J.; Horstman, C. C.; Marvin, J. G.; Viegas, J. R.; Bardina, J. E.; Huang, P. G.; Kussoy, M. I.

    1994-01-01

    The basic objective of this research was to identify, develop and recommend turbulence models which could be incorporated into CFD codes used in the design of the National AeroSpace Plane vehicles. To accomplish this goal, a combined effort consisting of experimental and theoretical phases was undertaken. The experimental phase consisted of a literature survey to collect and assess a database of well documented experimental flows, with emphasis on high speed or hypersonic flows, which could be used to validate turbulence models. Since it was anticipated that this database would be incomplete and would need supplementing, additional experiments in the NASA Ames 3.5-Foot Hypersonic Wind Tunnel (HWT) were also undertaken. The theoretical phase consisted of identifying promising turbulence models through applications to simple flows, and then investigating more promising models in applications to complex flows. The complex flows were selected from the database developed in the first phase of the study. For these flows it was anticipated that model performance would not be entirely satisfactory, so that model improvements or corrections would be required. The primary goals of the investigation were essentially achieved. A large database of flows was collected and assessed, a number of additional hypersonic experiments were conducted in the Ames HWT, and two turbulence models (kappa-epsilon and kappa-omega models with corrections) were determined which gave superior performance for most of the flows studied and are now recommended for NASP applications.

  9. Natural Colorants: Food Colorants from Natural Sources.

    Science.gov (United States)

    Sigurdson, Gregory T; Tang, Peipei; Giusti, M Mónica

    2017-02-28

    The color of food is often associated with the flavor, safety, and nutritional value of the product. Synthetic food colorants have been used because of their high stability and low cost. However, consumer perception and demand have driven the replacement of synthetic colorants with naturally derived alternatives. Natural pigment applications can be limited by lower stability, weaker tinctorial strength, interactions with food ingredients, and inability to match desired hues. Therefore, no single naturally derived colorant can serve as a universal alternative for a specified synthetic colorant in all applications. This review summarizes major environmental and biological sources for natural colorants as well as nature-identical counterparts. Chemical characteristics of prevalent pigments, including anthocyanins, carotenoids, betalains, and chlorophylls, are described. The possible applications and hues (warm, cool, and achromatic) of currently used natural pigments, such as anthocyanins as red and blue colorants, and possible future alternatives, such as purple violacein and red pyranoanthocyanins, are also discussed.

  10. CTE Corrections for WFPC2 and ACS

    Science.gov (United States)

    Dolphin, Andrew

    2003-07-01

    The error budget for optical broadband photometry is dominated by three factors: CTE corrections, long-short anomaly corrections, and photometric zero points. Questions about the dependencies of the CTE have largely been resolved, and my CTE corrections have been included in the WFPC2 handbook and tutorial. What remains to be done is the determination of the "final" CTE correction at the end of the WFPC2 mission, which will increase the accuracy of photometry obtained in the final few cycles. The long-short anomaly is still the subject of much debate, as it remains unclear whethere or not this effect is real and, if so, what its size and nature is. Photometric zero points have likewise varied by over 0.05 magnitudes in the literature, and will likely remain unresolved until the long-short anomaly is addressed {given that most calibration exposures are short while most science exposures are long}. It is also becoming apparent that similar issues will affect the accuracy of ACS photometry, and consequently that an ACS CTE study analogous to my WFPC2 work would significantly improve the calibration of ACS. I therefore propose to use archival WFPC2 images of omega Cen and ACS images of 47 Tuc to continue my HST calibration work. I also propose to begin work on "next-generation" CTE corrections, in which corrections are applied to the images based on accurate charge-trapping models rather than to the reduced photometry. This technique will allow for more accurate CTE corrections in certain cases {such as a star above a bright star or on a variable background}, improved PSF-fitting photometry of faint stars, and image restoration for accurate analysis of extended objects.

  11. Comparison at Necropsy of Heart Weight in Women Aged 20 to 29 Years With Fatal Trauma or Chemical Intoxication Versus Fatal Natural Cause (A Search for the Normal Adult Heart Weight).

    Science.gov (United States)

    Blackbourne, Brian D; Vasudevan, Anupama; Roberts, William C

    2017-03-01

    The present obesity epidemic makes determining the normal heart weight in adults difficult. This study examines the heart weight at autopsy in 104 women aged 20 to 29 years who died in 1978 to 1980 before the overweight epidemic ensued. Of the 104 cases, the hearts weighed ≤300 g in 86 (83%) and >300 g in 18 (17%). Of the 67 cases dying from an unnatural cause (trauma or chemical intoxication), only 3 (4%) had hearts weighing >300 g; of the 37 patients dying from a variety of natural causes, 15 (41%) had hearts weighing >300 g (p hearts in them ranged from 120 to 400 g (mean 262 ± 51; median 257 g); of the 22 cases (21%) in whom the BMI was >25 kg/m2, the hearts ranged from 230 to 850 g (mean 351 ± 142; median 300 g). In conclusion, the cases dying from an unnatural cause had smaller mean heart weights than those women dying from a natural cause and those with a normal BMI (≤25 kg/m2) had smaller mean heart weights than those with a BMI >25 kg/m2. The normal heart weight in young women dying from an unnatural cause with few exceptions is <300 g. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Holographic corrections to meson scattering amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Armoni, Adi; Ireson, Edwin, E-mail: 746616@swansea.ac.uk

    2017-06-15

    We compute meson scattering amplitudes using the holographic duality between confining gauge theories and string theory, in order to consider holographic corrections to the Veneziano amplitude and associated higher-point functions. The generic nature of such computations is explained, thanks to the well-understood nature of confining string backgrounds, and two different examples of the calculation in given backgrounds are used to illustrate the details. The effect we discover, whilst only qualitative, is re-obtainable in many such examples, in four-point but also higher point amplitudes.

  13. The biological correction is the new way of preservation of the Face of the Earth

    Science.gov (United States)

    Popov, Alexander

    2014-05-01

    The major links of terrestrial ecosystems functioning are: composted organic material with mull humus type, nitrogen-fixing microorganisms and litholytic organisms, which capable of active biological weathering of minerals and/or rock in the soil. Now the main ways of influence on plant-soil system functioning are physical and chemical correction. Physical correction is the system of different soil cultivation and land reclamation. It directed on creation and maintenance of favorable water, thermal and air regimes and also the biological activity of soils for crops. Although the general tendency of agriculture is minimized of tillage (strip-till, mini-till and no-till), nevertheless the intensive cultivation is widely used in modern agriculture. Chemical correction is the agriculture chemicalixation. It directed on regulation of plant producing by replenishment of plant, mineral nutrition elements in soils, by foliar nutrition using water solutions of macro- and microelements, and by regulation of acidic and salt soil regimes. In this case the plant protection against the pests and infections is carried out by various pesticides. This way of correction is completely realized in agriculture, but it doesn't consider the natural laws due to plants together with the soil from the interconnected and interdependent system. The continuing increase of agriculture chemicalixation simultaneously with a repeated tillage is led to loss of the major links of plant-soil systems functioning and to the degradation of a soil cover. Such way of plant productivity is a deadlock. New evolutionary way of preservation of the Face of the Earth is biological correction of plant-soil system functioning. A gist of this correction is the replenishment of the lost plant-soil system links. Biological correction leans on scientific achievements of modern biotechnologies, such as: vermicomposting, microbiologic specimens, physiologically active substances, biological agents of plant protection

  14. 75 FR 16516 - Dates Correction

    Science.gov (United States)

    2010-04-01

    ... From the Federal Register Online via the Government Publishing Office ] NATIONAL ARCHIVES AND RECORDS ADMINISTRATION Office of the Federal Register Dates Correction Correction In the Notices section... through 15499, the date at the top of each page is corrected to read ``Monday, March 29, 2010''. This...

  15. 77 FR 39899 - Technical Corrections

    Science.gov (United States)

    2012-07-06

    ..., correcting authority citations and typographical and spelling errors, and making other edits and conforming... I office; correcting typographical and spelling errors; and making other edits and conforming...).'' Correct Typographical Error. In Sec. 73.55(i)(4)(ii)(G), the word ``the'' was omitted due to a clerical...

  16. Job Satisfaction in Correctional Officers.

    Science.gov (United States)

    Diehl, Ron J.

    For more than a decade, correctional leaders throughout the country have attempted to come to grips with the basic issues involved in ascertaining and meeting the needs of correctional institutions. This study investigated job satisfaction in 122 correctional officers employed in both rural and urban prison locations for the State of Kansas…

  17. 78 FR 34245 - Miscellaneous Corrections

    Science.gov (United States)

    2013-06-07

    ... office, correcting and adding missing cross-references, correcting grammatical errors, revising language... grammatical errors, revising language for clarity and consistency, and specifying metric units. This document... Correct Grammatical Error. In Sec. 73.6, paragraph (a) is revised to replace the colon at the end of the...

  18. Agrosearch 2015. Corrected

    African Journals Online (AJOL)

    caryophyllene (11.8%), terpinolene (9.8%) and 1, 8-cineole (7.3%). The extracts of the leaves of H. suaveolens are nematicidal and holds promise as a natural bio-degradable alternative crop protectant against Heterodera sacchari. Key words: Heterodera sacchari, dichloromethane, essential oil,Hyptis suaveolens.

  19. Anomaly corrected heterotic horizons

    Energy Technology Data Exchange (ETDEWEB)

    Fontanella, A.; Gutowski, J.B. [Department of Mathematics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Papadopoulos, G. [Department of Mathematics, King’s College London,Strand, London WC2R 2LS (United Kingdom)

    2016-10-21

    We consider supersymmetric near-horizon geometries in heterotic supergravity up to two loop order in sigma model perturbation theory. We identify the conditions for the horizons to admit enhancement of supersymmetry. We show that solutions which undergo supersymmetry enhancement exhibit an sl(2,ℝ) symmetry, and we describe the geometry of their horizon sections. We also prove a modified Lichnerowicz type theorem, incorporating α{sup ′} corrections, which relates Killing spinors to zero modes of near-horizon Dirac operators. Furthermore, we demonstrate that there are no AdS{sub 2} solutions in heterotic supergravity up to second order in α{sup ′} for which the fields are smooth and the internal space is smooth and compact without boundary. We investigate a class of nearly supersymmetric horizons, for which the gravitino Killing spinor equation is satisfied on the spatial cross sections but not the dilatino one, and present a description of their geometry.

  20. Cool Cluster Correctly Correlated

    Energy Technology Data Exchange (ETDEWEB)

    Varganov, Sergey Aleksandrovich [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    Atomic clusters are unique objects, which occupy an intermediate position between atoms and condensed matter systems. For a long time it was thought that physical and chemical properties of atomic dusters monotonically change with increasing size of the cluster from a single atom to a condensed matter system. However, recently it has become clear that many properties of atomic clusters can change drastically with the size of the clusters. Because physical and chemical properties of clusters can be adjusted simply by changing the cluster's size, different applications of atomic clusters were proposed. One example is the catalytic activity of clusters of specific sizes in different chemical reactions. Another example is a potential application of atomic clusters in microelectronics, where their band gaps can be adjusted by simply changing cluster sizes. In recent years significant advances in experimental techniques allow one to synthesize and study atomic clusters of specified sizes. However, the interpretation of the results is often difficult. The theoretical methods are frequently used to help in interpretation of complex experimental data. Most of the theoretical approaches have been based on empirical or semiempirical methods. These methods allow one to study large and small dusters using the same approximations. However, since empirical and semiempirical methods rely on simple models with many parameters, it is often difficult to estimate the quantitative and even qualitative accuracy of the results. On the other hand, because of significant advances in quantum chemical methods and computer capabilities, it is now possible to do high quality ab-initio calculations not only on systems of few atoms but on clusters of practical interest as well. In addition to accurate results for specific clusters, such methods can be used for benchmarking of different empirical and semiempirical approaches. The atomic clusters studied in this work contain from a few atoms

  1. Corrective Action Investigation Plan for Corrective Action Unit 571: Area 9 Yucca Flat Plutonium Dispersion Sites, Nevada National Security Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Bernadine; Matthews, Patrick

    2013-07-01

    CAU 571 is a grouping of sites where there has been a suspected release of contamination associated with nuclear testing. This document describes the planned investigation of CAU 571, which comprises the following corrective action sites (CASs): • 09-23-03, Atmospheric Test Site S-9F • 09-23-04, Atmospheric Test Site T9-C • 09-23-12, Atmospheric Test Site S-9E • 09-23-13, Atmospheric Test Site T-9D • 09-45-01, Windrows Crater These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives (CAAs). Additional information will be obtained by conducting a corrective action investigation before evaluating CAAs and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable CAAs that will be presented in the investigation report. The sites will be investigated based on the data quality objectives (DQOs) developed on March 6, 2013, by representatives of the Nevada Division of Environmental Protection and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (now the Nevada Field Office). The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 571. The site investigation process will also be conducted in accordance with the Soils Activity Quality Assurance Plan, which establishes requirements, technical planning, and general quality practices to be applied to this activity. The potential contamination sources associated with CAU 571 CASs are from nuclear testing activities. The DQO process resulted in an assumption that total effective dose (TED) within a default contamination boundary exceeds the final action level (FAL) and requires corrective action. The presence and nature of contamination outside the default

  2. Rulison Site corrective action report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    Project Rulison was a joint US Atomic Energy Commission (AEC) and Austral Oil Company (Austral) experiment, conducted under the AEC`s Plowshare Program, to evaluate the feasibility of using a nuclear device to stimulate natural gas production in low-permeability gas-producing geologic formations. The experiment was conducted on September 10, 1969, and consisted of detonating a 40-kiloton nuclear device at a depth of 2,568 m below ground surface (BGS). This Corrective Action Report describes the cleanup of petroleum hydrocarbon- and heavy-metal-contaminated sediments from an old drilling effluent pond and characterization of the mud pits used during drilling of the R-EX well at the Rulison Site. The Rulison Site is located approximately 65 kilometers (40 miles) northeast of Grand Junction, Colorado. The effluent pond was used for the storage of drilling mud during drilling of the emplacement hole for the 1969 gas stimulation test conducted by the AEC. This report also describes the activities performed to determine whether contamination is present in mud pits used during the drilling of well R-EX, the gas production well drilled at the site to evaluate the effectiveness of the detonation in stimulating gas production. The investigation activities described in this report were conducted during the autumn of 1995, concurrent with the cleanup of the drilling effluent pond. This report describes the activities performed during the soil investigation and provides the analytical results for the samples collected during that investigation.

  3. WATER POLLUTION BY NATURAL INORGANIC CHEMICALS IN ...

    African Journals Online (AJOL)

    very wide plain areas and is constituted by narrow belts of parallel faulting, sunken strips of land between a ... enrichment in the geothermal systems is attributed to the reaction of dissolved carbon dioxide with the rocks to .... for the enrichment of fluoride and chloride in acidic volcanic rocks. In line with above observation ...

  4. CHEMICAL TOXICITY OF URANIUM

    Directory of Open Access Journals (Sweden)

    Sermin Cam

    2007-06-01

    Full Text Available Uranium, occurs naturally in the earth’s crust, is an alpha emitter radioactive element from the actinide group. For this reason, U-235 and U-238, are uranium isotopes with long half lives, have got radiological toxicity. But, for natural-isotopic-composition uranium (NatU, there is greater risk from chemical toxicity than radiological toxicity. When uranium is get into the body with anyway, also its chemical toxicity must be thought. [TAF Prev Med Bull 2007; 6(3.000: 215-220

  5. Natural Childbirth

    Science.gov (United States)

    ... cold, ice Cold, Ice, and Snow Safety Natural Childbirth KidsHealth > For Parents > Natural Childbirth Print A A ... the pain, extremely empowering and rewarding. About Natural Childbirth Natural childbirth is a "low-tech" way of ...

  6. Siderophores of Stenotrophomonas maltophilia: detection and determination of their chemical nature Sideróforos de Stenotrophomonas maltophilia: detección y determinación de su naturaleza química

    Directory of Open Access Journals (Sweden)

    Carlos A. García

    2012-09-01

    Full Text Available Stenotrophomonas maltophilia is an emerging nosocomial pathogen. Despite the broad spectrum of syndromes associated with S. maltophilia infections, little is known about its virulence factors, including siderophore production. The aims of this work were to detect S. maltophilia siderophores and to determine their chemical nature. We studied 31 S. maltophilia isolates from device-associated infections, recovered over the period 2006-2011 at Hospital de Clínicas José de San Martin, Buenos Aires, Argentina, and the strain K279a, whose genome has been fully sequenced. The production of siderophores was screened by the chrome azurol S (CAS agar assay, previously modified to detect siderophores in this species. When grown on modified CAS agar plates, all the clinical isolates and K279a were CAS-positive for siderophore production. In order to determine the chemical nature of siderophores, the Csáky (hydroxamate-type and Arnow (catechol-type assays were used. All S. maltophilia isolates produced catechol-type siderophores, but hydroxamate-type siderophores were not detected.Stenotrophomonas maltophilia es un patógeno nosocomial emergente. A pesar de la variedad de infecciones que produce, poco se conoce acerca de sus factores de virulencia, incluida la producción de sideróforos. Nuestros objetivos fueron detectar sideróforos de S. maltophilia y determinar su naturaleza química. Se estudiaron 31 aislamientos provenientes de infecciones asociadas al uso de dispositivos médicos y la cepa K279a, cuyo genoma ha sido completamente secuenciado. Los aislamientos provenientes de infecciones se obtuvieron de pacientes asistidos en el Hospital de Clínicas José de San Martín (Buenos Aires, Argentina en el período 2006- 2011. Como método de tamizaje se empleó la técnica chrome azurol S (CAS en placa, luego de implementar una modificación para detectar sideróforos en esta especie. Dicha modificación permitió detectar la producción de sider

  7. Corrective Action Investigation plan for Corrective Action Unit 546: Injection Well and Surface Releases, Nevada Test Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Alfred Wickline

    2008-03-01

    Corrective Action Unit (CAU) 546 is located in Areas 6 and 9 of the Nevada Test Site, which is approximately 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 546 is comprised of two Corrective Action Sites (CASs) listed below: •06-23-02, U-6a/Russet Testing Area •09-20-01, Injection Well These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation (CAI) before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on November 8, 2007, by representatives of the Nevada Division of Environmental Protection and U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office. The DQO process has been used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 546.

  8. Corrective Action Investigation Plan for Corrective Action Unit 560: Septic Systems, Nevada Test Site, Nevada with ROTC1, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Grant Evenson

    2008-05-01

    Corrective Action Unit (CAU) 560 is located in Areas 3 and 6 of the Nevada Test Site, which is approximately 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 560 is comprised of the seven corrective action sites (CASs) listed below: • 03-51-01, Leach Pit • 06-04-02, Septic Tank • 06-05-03, Leach Pit • 06-05-04, Leach Bed • 06-59-03, Building CP-400 Septic System • 06-59-04, Office Trailer Complex Sewage Pond • 06-59-05, Control Point Septic System These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on January 22, 2008, by representatives from the Nevada Division of Environmental Protection; U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office; Stoller-Navarro Joint Venture; and National Security Technologies, LLC. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 560.

  9. Corrective Action Investigation Plan for Corrective Action Unit 556: Dry Wells and Surface Release Points Nevada Test Site, Nevada (Draft), Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Grant Evenson

    2007-02-01

    Corrective Action Unit  (CAU) 556, Dry Wells and Surface Release Points, is located in Areas 6 and 25 of the Nevada Test Site, 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 556 is comprised of four corrective action sites (CASs) listed below: •06-20-04, National Cementers Dry Well •06-99-09, Birdwell Test Hole •25-60-03, E-MAD Stormwater Discharge and Piping •25-64-01, Vehicle Washdown and Drainage Pit These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document.

  10. Scientific pluralism and the Chemical Revolution.

    Science.gov (United States)

    Kusch, Martin

    2015-02-01

    In a number of papers and in his recent book, Is Water H2O? Evidence, Realism, Pluralism (2012), Hasok Chang has argued that the correct interpretation of the Chemical Revolution provides a strong case for the view that progress in science is served by maintaining several incommensurable "systems of practice" in the same discipline, and concerning the same region of nature. This paper is a critical discussion of Chang's reading of the Chemical Revolution. It seeks to establish, first, that Chang's assessment of Lavoisier's and Priestley's work and character follows the phlogistonists' "actors' sociology"; second, that Chang simplifies late-eighteenth-century chemical debates by reducing them to an alleged conflict between two systems of practice; third, that Chang's evidence for a slow transition from phlogistonist theory to oxygen theory is not strong; and fourth, that he is wrong to assume that chemists at the time did not have overwhelming good reasons to favour Lavoisier's over the phlogistonists' views. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Chemical use

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of research and activities related to chemical use on Neal Smith National Wildlife Refuge between 1992 and 2009. The chemicals used on the Refuge...

  12. Processor register error correction management

    Energy Technology Data Exchange (ETDEWEB)

    Bose, Pradip; Cher, Chen-Yong; Gupta, Meeta S.

    2016-12-27

    Processor register protection management is disclosed. In embodiments, a method of processor register protection management can include determining a sensitive logical register for executable code generated by a compiler, generating an error-correction table identifying the sensitive logical register, and storing the error-correction table in a memory accessible by a processor. The processor can be configured to generate a duplicate register of the sensitive logical register identified by the error-correction table.

  13. Estimation of the influence that natural fires have on air pollution in the region of Moscow megalopolis based on the combined use of chemical transport model and measurement data

    Science.gov (United States)

    Konovalov, I. B.; Beekmann, M.; Kuznetsova, I. N.; Glazkova, A. A.; Vasil'Eva, A. V.; Zaripov, R. B.

    2011-08-01

    Satellite measurements of the fire radiation power, measurements of atmospheric pollution in the network of GPU Mosekomonitoring stations, and the modern CHIMERE chemical transport model (CHIMERE CTM) are used for estimating the influence that forest fires have on the air pollution level in the Moscow megalopolis region during the summer of 2007. The method by which the radiation power caused by natural fires determined from satellite measurements is converted into emissions of individual model species is described. General problems related to the optimization of estimates of fire emission and the effects caused by them based on the combined use of measurement data on the composition of the atmosphere and the CTM are considered using a concrete example. It is shown, in particular, that the use of the standard least squares method for the optimization of fire emissions from leads in the general case to obtaining biased (underestimated) estimates. The results of calculations consistent with measurements show that forest fires near Moscow can occasionally be responsible for a considerable part of the air pollution observed in Moscow and its vicinities, and they can be the main reason for the high level of atmospheric pollution in some neighboring regions.

  14. Effect of the natural and artificial drying of leaf biomass Piper hispidinervum on the chemical composition of the essential oilEfeito da secagem natural e artificial da biomassa foliar de Piper hispidinervum na composição química do óleo essencial

    Directory of Open Access Journals (Sweden)

    Marília Pereira Machado

    2013-03-01

    Full Text Available Piper hispidinervum C.DC. is a plant native to the Amazon region, produces an essential oil rich in safrole. The aim of this study was to evaluate the effect of different methods of drying biomass in chemical composition of the essential oil of P. hispidinervum cultivated in Morretes (PR. The treatments were: fresh leaves; natural drying for 6 and 12 days; oven drying at 40°C for 6 and 12 days. The essential oil was extracted by hydrodistillation from samples of 50 g of each treatment in triplicate. The chemical composition of essential oil was performed by gas chromatography coupled to mass spectrometer (GC/ MS. The experimental design was completely randomized design with three replication and four plants per plot. Data were subjected to analysis of variance. The type and drying time changes the chemical composition of the essential oil of P. hispidinervum. The dried at 40°C for 12 days reduce the amount of essential oil components, but with increasing content of safrole. Piper hispidinervum C.DC. é uma planta nativa da Amazônia, produtora de óleo essencial rico em safrol. O objetivo do presente trabalho foi avaliar o efeito de diferentes métodos de secagem da biomassa folia de pimenta longa (P. hispidinervum, cultivada em Morretes (PR, na composição química do óleo essencial. Os tratamentos avaliados foram: folhas frescas; secagem natural por 6 e 12 dias; secagem em estufa à 40°C por 6 e 12 dias. O óleo essencial foi extraído por hidrodestilação a partir de amostras de 50 g de cada tratamento em triplicata. A determinação da composição química do óleo essencial foi realizada por cromatografia gasosa acoplada ao espectrômetro de massa (GC/MS. O delineamento experimental foi inteiramente casualizado, com três repetições e quatro plantas por parcela. Os dados obtidos foram submetidos à análise de variância. O tipo e tempo de secagem alteram a constituição química do óleo essencial de pimenta-longa. A secagem em

  15. Program Derivation by Correctness Enhacements

    Directory of Open Access Journals (Sweden)

    Nafi Diallo

    2016-06-01

    Full Text Available Relative correctness is the property of a program to be more-correct than another program with respect to a given specification. Among the many properties of relative correctness, that which we found most intriguing is the property that program P' refines program P if and only if P' is more-correct than P with respect to any specification. This inspires us to reconsider program derivation by successive refinements: each step of this process mandates that we transform a program P into a program P' that refines P, i.e. P' is more-correct than P with respect to any specification. This raises the question: why should we want to make P' more-correct than P with respect to any specification, when we only have to satisfy specification R? In this paper, we discuss a process of program derivation that replaces traditional sequence of refinement-based correctness-preserving transformations starting from specification R by a sequence of relative correctness-based correctness-enhancing transformations starting from abort.

  16. Rank Modulation for Translocation Error Correction

    CERN Document Server

    Farnoud, Farzad; Milenkovic, Olgica

    2012-01-01

    We consider rank modulation codes for flash memories that allow for handling arbitrary charge drop errors. Unlike classical rank modulation codes used for correcting errors that manifest themselves as swaps of two adjacently ranked elements, the proposed \\emph{translocation rank codes} account for more general forms of errors that arise in storage systems. Translocations represent a natural extension of the notion of adjacent transpositions and as such may be analyzed using related concepts in combinatorics and rank modulation coding. Our results include tight bounds on the capacity of translocation rank codes, construction techniques for asymptotically good codes, as well as simple decoding methods for one class of structured codes. As part of our exposition, we also highlight the close connections between the new code family and permutations with short common subsequences, deletion and insertion error-correcting codes for permutations and permutation arrays.

  17. Black Holes, Holography, and Quantum Error Correction

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    How can it be that a local quantum field theory in some number of spacetime dimensions can "fake" a local gravitational theory in a higher number of dimensions?  How can the Ryu-Takayanagi Formula say that an entropy is equal to the expectation value of a local operator?  Why do such things happen only in gravitational theories?  In this talk I will explain how a new interpretation of the AdS/CFT correspondence as a quantum error correcting code provides satisfying answers to these questions, and more generally gives a natural way of generating simple models of the correspondence.  No familiarity with AdS/CFT or quantum error correction is assumed, but the former would still be helpful.  

  18. Clean slate corrective action investigation plan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    The Clean Slate sites discussed in this report are situated in the central portion of the Tonopah Test Range (TTR), north of the Nevada Test Site (NTS) on the northwest portion of the Nellis Air Force Range (NAFR) which is approximately 390 kilometers (km) (240 miles [mi]) northwest of Las Vegas, Nevada. These sites were the locations for three of the four Operation Roller Coaster experiments. These experiments evaluated the dispersal of plutonium in the environment from the chemical explosion of a plutonium-bearing device. Although it was not a nuclear explosion, Operation Roller Coaster created some surface contamination which is now the subject of a corrective action strategy being implemented by the Nevada Environmental Restoration Project (NV ERP) for the U.S. Department of Energy (DOE). Corrective Action Investigation (CAI) activities will be conducted at three of the Operation Roller Coaster sites. These are Clean Slate 1 (CS-1), Clean Slate 2 (CS-2), and Clean Slate 3 (CS-3) sites, which are located on the TTR. The document that provides or references all of the specific information relative to the various investigative processes is called the Corrective Action Investigation Plan (CAIP). This CAIP has been prepared for the DOE Nevada Operations Office (DOE/NV) by IT Corporation (IT).

  19. Corrective measures evaluation report for Tijeras Arroyo groundwater.

    Energy Technology Data Exchange (ETDEWEB)

    Witt, Johnathan L (North Wind, Inc., Idaho Falls, ID); Orr, Brennon R. (North Wind, Inc., Idaho Falls, ID); Dettmers, Dana L. (North Wind, Inc., Idaho Falls, ID); Hall, Kevin A. (North Wind, Inc., Idaho Falls, ID); Howard, M. Hope (North Wind, Inc., Idaho Falls, ID)

    2005-08-01

    This Corrective Measures Evaluation report was prepared as directed by a Compliance Order on Consent issued by the New Mexico Environment Department to document the process of selecting the preferred remedial alternative for Tijeras Arroyo Groundwater. Supporting information includes background concerning the site conditions and potential receptors and an overview of work performed during the Corrective Measures Evaluation. The evaluation of remedial alternatives included identifying and describing four remedial alternatives, an overview of the evaluation criteria and approach, comparing remedial alternatives to the criteria, and selecting the preferred remedial alternative. As a result of the Corrective Measures Evaluation, monitored natural attenuation of the contaminants of concern (trichloroethene and nitrate) is the preferred remedial alternative for implementation as the corrective measure for Tijeras Arroyo Groundwater. Design criteria to meet cleanup goals and objectives and the corrective measures implementation schedule for the preferred remedial alternative are also presented.

  20. Diamagnetic Corrections and Pascal's Constants

    Science.gov (United States)

    Bain, Gordon A.; Berry, John F.

    2008-01-01

    Measured magnetic susceptibilities of paramagnetic substances must typically be corrected for their underlying diamagnetism. This correction is often accomplished by using tabulated values for the diamagnetism of atoms, ions, or whole molecules. These tabulated values can be problematic since many sources contain incomplete and conflicting data.…

  1. Unpacking Corrections in Mobile Instruction

    DEFF Research Database (Denmark)

    Levin, Lena; Cromdal, Jakob; Broth, Mathias

    2017-01-01

    This article deals with the organisation of correction in mobile instructional settings. Five sets of video data (>250 h) documenting how learners were instructed to fly aeroplanes, drive cars and ride bicycles in real life traffic were examined to reveal some common features of correction exchan...

  2. Space mapping and defect correction

    NARCIS (Netherlands)

    Echeverría, D.; Hemker, P.W.

    2005-01-01

    In this paper we show that space-mapping optimization can be understood in the framework of defect correction. Then, space-mapping algorithms can be seen as special cases of defect correction iteration. In order to analyze the properties of space mapping and the space-mapping function, we introduce

  3. Correctional Officers With Case Loads

    Science.gov (United States)

    Ward, Richard J.; Vandergoot, David

    1977-01-01

    The Maryland Division of Correction has implemented an innovative program that permits correctional officers to combine counseling case-management functions with their custory functions. Basically, the program relies on the quality of individual programming that results from the close personal, working relationship developed between officer and…

  4. Food systems in correctional settings

    DEFF Research Database (Denmark)

    Smoyer, Amy; Kjær Minke, Linda

    Food is a central component of life in correctional institutions and plays a critical role in the physical and mental health of incarcerated people and the construction of prisoners' identities and relationships. An understanding of the role of food in correctional settings and the effective mana......, including a case study of food-related innovation in the Danish correctional system. It offers specific conclusions for policy-makers, administrators of correctional institutions and prison-food-service professionals, and makes proposals for future research.......Food is a central component of life in correctional institutions and plays a critical role in the physical and mental health of incarcerated people and the construction of prisoners' identities and relationships. An understanding of the role of food in correctional settings and the effective...... management of food systems may improve outcomes for incarcerated people and help correctional administrators to maximize their health and safety. This report summarizes existing research on food systems in correctional settings and provides examples of food programmes in prison and remand facilities...

  5. author's correction 1..1

    Indian Academy of Sciences (India)

    B Indian Academy of Sciences. Author's correction. Cullin-5 and cullin-2 play a role in the development of neuromuscular junction and the female germ line of Drosophila. Champakali Ayyub. J. Genet. 90, 239Y249. The correct figure 5A is as follows: Journal of Genetics, Vol. 90, No. 3, December 2011. 519.

  6. Jet Energy Corrections at CMS

    CERN Document Server

    Santocchia, Attilio

    2009-01-01

    Many physics measurements in CMS will rely on the precise reconstruction of Jets. Correction of the raw jet energy measured by the CMS detector will be a fundamental step for most of the analysis where hadron activity is investigated. Jet correction plans in CMS have been widely studied for different conditions: at stat-up simulation tuned on test-beam data will be used. Then data-driven methods will be available and finally, simulation tuned on collision data will give us the ultimate procedure for calculating jet corrections. Jet transverse energy is corrected first for pile-up and noise offset; correction for the response of the calorimeter as a function of jet pseudorapidity relative to the barrel comes afterwards and correction for the absolute response as a function of transverse momentum in the barrel is the final standard sub-correction applied. Other effects like flavour and parton correction will be optionally applied on the Jet $E_T$ depending on the measurement requests. In this paper w...

  7. GUP parameter from quantum corrections to the Newtonian potential

    Energy Technology Data Exchange (ETDEWEB)

    Scardigli, Fabio, E-mail: fabio@phys.ntu.edu.tw [Dipartimento di Matematica, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano (Italy); Department of Applied Mathematics, University of Waterloo, Ontario N2L 3G1 (Canada); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Lambiase, Gaetano, E-mail: lambiase@sa.infn.it [Dipartimento di Fisica “E.R. Caianiello”, Universita' di Salerno, I-84084 Fisciano (Italy); INFN – Gruppo Collegato di Salerno (Italy); Vagenas, Elias C., E-mail: elias.vagenas@ku.edu.kw [Theoretical Physics Group, Department of Physics, Kuwait University, P.O. Box 5969, Safat 13060 (Kuwait)

    2017-04-10

    We propose a technique to compute the deformation parameter of the generalized uncertainty principle by using the leading quantum corrections to the Newtonian potential. We just assume General Relativity as theory of Gravitation, and the thermal nature of the GUP corrections to the Hawking spectrum. With these minimal assumptions our calculation gives, to first order, a specific numerical result. The physical meaning of this value is discussed, and compared with the previously obtained bounds on the generalized uncertainty principle deformation parameter.

  8. Natural gas monthly, March 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    The March 1998 edition of the Natural Gas Monthly highlights activities, events, and analyses associated with the natural gas industry. Volume and price data are presented for natural gas production, distribution, consumption, and interstate pipeline activities. Producer-related activities and underground storage data are also reported. This report also features an article on the correction of errors in the drilling activity estimates series, and in-depth drilling activity data. 6 figs., 28 tabs.

  9. 77 FR 4228 - Technical Amendments and Corrections to DEA Regulations

    Science.gov (United States)

    2012-01-27

    ... Comprehensive Drug Abuse Prevention and Control Act of 1970, often referred to as the Controlled Substances Act..., standardization of ``a.k.a.'' names for substances listed under ``anabolic steroids,'' and correcting the spelling of four of the chemical names for substances listed under ``anabolic steroid'': boldenone...

  10. 76 FR 14818 - Chemical Testing

    Science.gov (United States)

    2011-03-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY Coast Guard 46 CFR Part 16 Chemical Testing CFR Correction In Title 46 of the Code of Federal Regulations, Parts 1 to 40, revised as of October 1, 2010, on page 254, in Sec. 16.105, in the definition of...

  11. Natural minimal dark matter

    CERN Document Server

    Fabbrichesi, Marco

    2016-01-01

    We show how the Higgs boson mass is protected from the potentially large corrections due to the introduction of minimal dark matter if the new physics sector is made supersymmetric. The fermionic dark matter candidate (a 5-plet of $SU(2)_L$) is accompanied by a scalar state. The weak gauge sector is made supersymmetric and the Higgs boson is embedded in a supersymmetric multiplet. The remaining standard model states are non-supersymmetric. Non vanishing corrections to the Higgs boson mass only appear at three-loop level and the model is natural for dark matter masses up to 15 TeV--a value larger than the one required by the cosmological relic density. The construction presented stands as an example of a general approach to naturalness that solves the little hierarchy problem which arises when new physics is added beyond the standard model at an energy scale around 10 TeV.

  12. Quantum correction to the entropy of noncommutative BTZ black hole

    Science.gov (United States)

    Anacleto, M. A.; Brito, F. A.; Cavalcanti, A. G.; Passos, E.; Spinelly, J.

    2018-02-01

    In this paper we consider the generalized uncertainty principle (GUP) in the tunneling formalism via Hamilton-Jacobi method to determine the quantum-corrected Hawking temperature and entropy for noncommutative BTZ black hole. In our results we obtain several types of corrections including the expected logarithmic correction to the area entropy associated with the noncommutative BTZ black holes. We also show that the area entropy product of the noncommutative BTZ black holes is dependent on mass and by analyzing the nature of the specific heat capacity we have observed that the noncommutative BTZ black hole is stable at some range of parameters.

  13. [Chemical weapons and chemical terrorism].

    Science.gov (United States)

    Nakamura, Katsumi

    2005-10-01

    Chemical Weapons are kind of Weapons of Mass Destruction (WMD). They were used large quantities in WWI. Historically, large quantities usage like WWI was not recorded, but small usage has appeared now and then. Chemical weapons are so called "Nuclear weapon for poor countrys" because it's very easy to produce/possession being possible. They are categorized (1) Nerve Agents, (2) Blister Agents, (3) Cyanide (blood) Agents, (4) Pulmonary Agents, (5) Incapacitating Agents (6) Tear Agents from the viewpoint of human body interaction. In 1997 the Chemical Weapons Convention has taken effect. It prohibits chemical weapons development/production, and Organization for the Prohibition of Chemical Weapons (OPCW) verification regime contributes to the chemical weapons disposal. But possibility of possession/use of weapons of mass destruction by terrorist group represented in one by Matsumoto and Tokyo Subway Sarin Attack, So new chemical terrorism countermeasures are necessary.

  14. Corrective Action Investigation Plan for Corrective Action Unit 145: Wells and Storage Holes, Nevada Test Site, Nevada, Rev. No.: 0

    Energy Technology Data Exchange (ETDEWEB)

    David A. Strand

    2004-09-01

    This Corrective Action Investigation Plan (CAIP) contains project-specific information for conducting site investigation activities at Corrective Action Unit (CAU) 145: Wells and Storage Holes. Information presented in this CAIP includes facility descriptions, environmental sample collection objectives, and criteria for the selection and evaluation of environmental samples. Corrective Action Unit 145 is located in Area 3 of the Nevada Test Site, which is 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 145 is comprised of the six Corrective Action Sites (CASs) listed below: (1) 03-20-01, Core Storage Holes; (2) 03-20-02, Decon Pad and Sump; (3) 03-20-04, Injection Wells; (4) 03-20-08, Injection Well; (5) 03-25-01, Oil Spills; and (6) 03-99-13, Drain and Injection Well. These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation (CAI) prior to evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document. One conceptual site model with three release scenario components was developed for the six CASs to address all releases associated with the site. The sites will be investigated based on data quality objectives (DQOs) developed on June 24, 2004, by representatives of the Nevada Division of Environmental Protection; U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office; Stoller-Navarro Joint Venture; and Bechtel Nevada. The DQOs process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 145.

  15. Chemical Analysis of Tire Traces in Traffic Accidents Investigation

    Directory of Open Access Journals (Sweden)

    Line Gueissaz

    2015-01-01

    Full Text Available The aim of the forensic investigation of traffic accidents is to help establish the nature and/or the circumstances of the event. This might be done with the purpose of determining the legal responsibilities of each person involved or to provide families, with a reconstruction of the events, to help understand why their relatives were injured or killed. A methodology for the comparison of chemical profiles of tire traces and tire tread samples obtained by pyrolysis-gas chromatography/mass spectrometry has been developed. Chemical profiles are represented by relative abundances of 86 compounds. The variability of the tread within and between 12 tires was assessed. Considering the level of the source as "brand and model" the intra-variability was found to be smaller than the inter-variability, leading to the complete discrimination of the 12 tires of the sample set. Braking tests were carried out on a racetrack in order to produce tire traces which origin was known. The results obtained with a supervised classification method showed that more than 94% of the replicates of the traces were correctly assigned to the class membership (i.e., brand and model of the tire at their origin. These results support that the chemical profile of one trace does not differ from the chemical profile of the tire at its origin but differs generally from the other chemical profiles of the sample set.

  16. Protein Chemical Shift Prediction

    CERN Document Server

    Larsen, Anders S

    2014-01-01

    The protein chemical shifts holds a large amount of information about the 3-dimensional structure of the protein. A number of chemical shift predictors based on the relationship between structures resolved with X-ray crystallography and the corresponding experimental chemical shifts have been developed. These empirical predictors are very accurate on X-ray structures but tends to be insensitive to small structural changes. To overcome this limitation it has been suggested to make chemical shift predictors based on quantum mechanical(QM) calculations. In this thesis the development of the QM derived chemical shift predictor Procs14 is presented. Procs14 is based on 2.35 million density functional theory(DFT) calculations on tripeptides and contains corrections for hydrogen bonding, ring current and the effect of the previous and following residue. Procs14 is capable at performing predictions for the 13CA, 13CB, 13CO, 15NH, 1HN and 1HA backbone atoms. In order to benchmark Procs14, a number of QM NMR calculatio...

  17. Chemical evolution and life

    Directory of Open Access Journals (Sweden)

    Malaterre Christophe

    2015-01-01

    Full Text Available In research on the origins of life, the concept of “chemical evolution” aims at explaining the transition from non-living matter to living matter. There is however strong disagreement when it comes to defining this concept more precisely, and in particular with reference to a chemical form of Darwinian evolution: for some, chemical evolution is nothing but Darwinian evolution applied to chemical systems before life appeared; yet, for others, it is the type of evolution that happened before natural selection took place, the latter being the birthmark of living systems. In this contribution, I review the arguments defended by each side and show how both views presuppose a dichotomous definition of “life”.

  18. Chemical Composition

    Science.gov (United States)

    May, Willie; Cavanagh, Richard; Turk, Gregory; Winchester, Michael; Travis, John; Smith, Melody; Derose, Paul; Choquette, Steven; Kramer, Gary; Sieber, John; Greenberg, Robert; Lindstrom, Richard; Lamaze, George; Zeisler, Rolf; Schantz, Michele; Sander, Lane; Phinney, Karen; Welch, Michael; Vetter, Thomas; Pratt, Kenneth; Scott, John; Small, John; Wight, Scott; Stranick, Stephan

    Measurements of the chemical compositions of materials and the levels of certain substances in them are vital when assessing and improving public health, safety and the environment, are necessary to ensure trade equity, and are required when monitoring and improving industrial products and services. Chemical measurements play a crucial role in most areas of the economy, including healthcare, food and nutrition, agriculture, environmental technologies, chemicals and materials, instrumentation, electronics, forensics, energy, and transportation.

  19. Better than Nature: Nicotinamide Biomimetics That Outperform Natural Coenzymes

    NARCIS (Netherlands)

    Knaus, T.; Paul, C.E.; Levy, C.W.; de Vries, S.; Mutti, F.G.; Hollmann, F.; Scrutton, N.S.

    2016-01-01

    The search for affordable, green biocatalytic processes is a challenge for chemicals manufacture. Redox biotransformations are potentially attractive, but they rely on unstable and expensive nicotinamide coenzymes that have prevented their widespread exploitation. Stoichiometric use of natural

  20. Chemical oceanography

    National Research Council Canada - National Science Library

    Millero, F.J

    1996-01-01

    Chemical Oceanography presents a comprehensive examination of the chemistry of oceans through discussions of such topics as descriptive physical oceanography, the composition of seawater and the major...

  1. Effect of water table variations and input of natural organic matter on the cycles of C and N, and mobility of As, Zn and Cu from a soil impacted by the burning of chemical warfare agents: A mesocosm study.

    Science.gov (United States)

    Thouin, Hugues; Battaglia-Brunet, Fabienne; Gautret, Pascale; Le Forestier, Lydie; Breeze, Dominique; Séby, Fabienne; Norini, Marie-Paule; Dupraz, Sebastien

    2017-10-01

    A mesocosm study was conducted to assess the impact of water saturation episodes and of the input of bioavailable organic matter on the biogeochemical cycles of C and N, and on the behavior of metal(loid)s in a soil highly contaminated by the destruction of arsenical shells. An instrumented mesocosm was filled with contaminated soil taken from the "Place-à-Gaz" site. Four cycles of dry and wet periods of about one month were simulated for 276days. After two dry/wet cycles, organic litter sampled on the site was added above the topsoil. The nitrogen cycle was the most impacted by the wet/dry cycles, as evidenced by a denitrification microbial process in the saturated level. The concentrations of the two most mobile pollutants, Zn and As, in the soil water and in the mesocosm leachate were, respectively, in the 0.3-1.6mM and 20-110μM ranges. After 8months of experiment, about 83g·m -3 of Zn and 3.5g·m -3 of As were leached from the soil. These important quantities represent cycles had no major effect on Zn mobility. However, soil saturation induced the immobilization of As by trapping As V but enhanced As III mobility. These phenomena were amplified by the presence of bioavailable organic matter. The study showed that the natural deposition of forest organic litter allowed a part of the soil's biological function to be restored but did not immobilize all the Zn and As, and even contributed to transport of As III to the surrounding environment. The main hazard of this type of site, contaminated by organo-arsenic chemical weapons, is the constitution of a stock of As that may leach into the surrounding environment for several hundred years. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Integrating ecotoxicity and chemical approaches to compare the effects of ZnO nanoparticles, ZnO bulk, and ZnCl2 on plants and microorganisms in a natural soil.

    Science.gov (United States)

    García-Gómez, C; Babin, M; Obrador, A; Álvarez, J M; Fernández, M D

    2015-11-01

    This work compared the toxicity of ZnO nanoparticles (ZnO-NPs), ZnO bulk, and ZnCl2 on microbial activity (C and N transformations and dehydrogenase and phosphatase activities) and their uptake and toxic effects (emergence, root elongation, and shoot growth) on three plant species namely wheat, radish, and vetch in a natural soil at 1000 mg Zn kg(-1). Additionally, plants were also tested at 250 mg Zn kg(-1). The effects of the chemical species on Zn extractability in soil were studied by performing single and sequential extractions. ZnCl2-1000 presented the highest toxicity for both taxonomic groups. For microorganisms, ZnO-NPs demonstrated adverse effects on all measured parameters, except on N transformations. The effects of both ZnO forms were similar. For plants, ZnO-NPs affected the growth of more plant species than ZnO bulk, although the effects were small in all cases. Regarding accumulation, the total Zn amounts were higher in plants exposed to ZnO-NP than those exposed to ZnO bulk, except for vetch shoots. The soil sequential extraction revealed that the Zn concentration in the most labile forms (water soluble (WS) and exchangeable (EX)) was similar in soil treated with ZnO (NP and bulk) and lower than that of ZnCl2-treated soil, indicating the higher availability of the ionic forms. The strong correlations obtained between WS-Zn fraction and the Zn concentrations in the roots, shoots, and the effects on shoot weight show the suitability of this soil extraction method for predicting bioavailable Zn soil for the three plant species when it was added as ZnO-NPs, ZnO bulk, or ZnCl2. In this work, the hazard associated with the ZnO-NPs was similar to ZnO bulk in most cases.

  3. Corrective Action Investigation Plan for Corrective Action Unit 573: Alpha Contaminated Sites, Nevada National Security Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, Patrick

    2014-05-01

    Corrective Action Unit (CAU) 573 is located in Area 5 of the Nevada National Security Site, which is approximately 65 miles northwest of Las Vegas, Nevada. CAU 573 is a grouping of sites where there has been a suspected release of contamination associated with non-nuclear experiments and nuclear testing. This document describes the planned investigation of CAU 573, which comprises the following corrective action sites (CASs): • 05-23-02, GMX Alpha Contaminated Area • 05-45-01, Atmospheric Test Site - Hamilton These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives.

  4. Errors in Chemical Sensor Measurements

    Directory of Open Access Journals (Sweden)

    Artur Dybko

    2001-06-01

    Full Text Available Various types of errors during the measurements of ion-selective electrodes, ionsensitive field effect transistors, and fibre optic chemical sensors are described. The errors were divided according to their nature and place of origin into chemical, instrumental and non-chemical. The influence of interfering ions, leakage of the membrane components, liquid junction potential as well as sensor wiring, ambient light and temperature is presented.

  5. Linear network error correction coding

    CERN Document Server

    Guang, Xuan

    2014-01-01

    There are two main approaches in the theory of network error correction coding. In this SpringerBrief, the authors summarize some of the most important contributions following the classic approach, which represents messages by sequences?similar to algebraic coding,?and also briefly discuss the main results following the?other approach,?that uses the theory of rank metric codes for network error correction of representing messages by subspaces. This book starts by establishing the basic linear network error correction (LNEC) model and then characterizes two equivalent descriptions. Distances an

  6. Correction tool for Active Shape Model based lumbar muscle segmentation.

    Science.gov (United States)

    Valenzuela, Waldo; Ferguson, Stephen J; Ignasiak, Dominika; Diserens, Gaelle; Vermathen, Peter; Boesch, Chris; Reyes, Mauricio

    2015-08-01

    In the clinical environment, accuracy and speed of the image segmentation process plays a key role in the analysis of pathological regions. Despite advances in anatomic image segmentation, time-effective correction tools are commonly needed to improve segmentation results. Therefore, these tools must provide faster corrections with a low number of interactions, and a user-independent solution. In this work we present a new interactive correction method for correcting the image segmentation. Given an initial segmentation and the original image, our tool provides a 2D/3D environment, that enables 3D shape correction through simple 2D interactions. Our scheme is based on direct manipulation of free form deformation adapted to a 2D environment. This approach enables an intuitive and natural correction of 3D segmentation results. The developed method has been implemented into a software tool and has been evaluated for the task of lumbar muscle segmentation from Magnetic Resonance Images. Experimental results show that full segmentation correction could be performed within an average correction time of 6±4 minutes and an average of 68±37 number of interactions, while maintaining the quality of the final segmentation result within an average Dice coefficient of 0.92±0.03.

  7. Higher order QCD corrections in small x physics

    Energy Technology Data Exchange (ETDEWEB)

    Chachamis, G.

    2006-11-15

    We study higher order QCD corrections in small x Physics. The numerical implementation of the full NLO photon impact factor is the remaining necessary piece for the testing of the NLO BFKL resummation against data from physical processes, such as {gamma}{sup *}{gamma}{sup *} collisions. We perform the numerical integration over phase space for the virtual corrections to the NLO photon impact factor. This, along with the previously calculated real corrections, makes feasible in the near future first estimates for the {gamma}*{gamma}* total cross section, since the convolution of the full impact factor with the NLO BFKL gluon Green's function is now straightforward. The NLO corrections for the photon impact factor are sizeable and negative. In the second part of this thesis, we estimate higher order correction to the BK equation. We are mainly interested in whether partonic saturation delays or not in rapidity when going beyond the leading order. In our investigation, we use the so called 'rapidity veto' which forbid two emissions to be very close in rapidity, to 'switch on' higher order corrections to the BK equation. From analytic and numerical analysis, we conclude that indeed saturation does delay in rapidity when higher order corrections are taken into account. In the last part, we investigate higher order QCD corrections as additional corrections to the Electroweak (EW) sector. The question of whether BFKL corrections are of any importance in the Regge limit for the EW sector seems natural; although they arise in higher loop level, the accumulation of logarithms in energy s at high energies, cannot be dismissed without an investigation. We focus on the process {gamma}{gamma}{yields}ZZ. We calculate the pQCD corrections in the forward region at leading logarithmic (LL) BFKL accuracy, which are of the order of few percent at the TeV energy scale. (orig.)

  8. Development of a Drosophila cell-based error correction assay

    Directory of Open Access Journals (Sweden)

    Jeffrey D. Salemi

    2013-07-01

    Full Text Available Accurate transmission of the genome through cell division requires microtubules from opposing spindle poles to interact with protein super-structures called kinetochores that assemble on each sister chromatid. Most kinetochores establish erroneous attachments that are destabilized through a process called error correction. Failure to correct improper kinetochore-microtubule (kt-MT interactions before anaphase onset results in chromosomal instability (CIN, which has been implicated in tumorigenesis and tumor adaptation. Thus, it is important to characterize the molecular basis of error correction to better comprehend how CIN occurs and how it can be modulated. An error correction assay has been previously developed in cultured mammalian cells in which incorrect kt-MT attachments are created through the induction of monopolar spindle assembly via chemical inhibition of kinesin-5. Error correction is then monitored following inhibitor wash out. Implementing the error correction assay in Drosophila melanogaster S2 cells would be valuable because kt-MT attachments are easily visualized and the cells are highly amenable to RNAi and high-throughput screening. However, Drosophila kinesin-5 (Klp61F is unaffected by available small molecule inhibitors. To overcome this limitation, we have rendered S2 cells susceptible to kinesin-5 inhibitors by functionally replacing Klp61F with human kinesin-5 (Eg5. Eg5 expression rescued the assembly of monopolar spindles typically caused by Klp61F depletion. Eg5-mediated bipoles collapsed into monopoles due to the activity of kinesin-14 (Ncd when treated with the kinesin-5 inhibitor S-trityl-L-cysteine (STLC. Furthermore, bipolar spindles reassembled and error correction was observed after STLC wash out. Importantly, error correction in Eg5-expressing S2 cells was dependent on the well-established error correction kinase Aurora B. This system provides a powerful new cell-based platform for studying error correction and

  9. Chemical Reaction: Diagnosis and Towards Remedy of ...

    African Journals Online (AJOL)

    Experience and literature show that most high school students do not have the correct mental models of coefficients and subscripts in chemical reactions. To contribute towards the conceptual reconstruction of scientific mental models of coefficients and subscripts in a chemical reaction a new teaching-learning strategy is ...

  10. Chemical intolerance

    DEFF Research Database (Denmark)

    Dantoft, Thomas Meinertz; Andersson, Linus; Nordin, Steven

    2015-01-01

    Chemical intolerance (CI) is a term used to describe a condition in which the sufferer experiences a complex array of recurrent unspecific symptoms attributed to low-level chemical exposure that most people regard as unproblematic. Severe CI constitutes the distinguishing feature of multiple...

  11. Libertarian Anarchism Is Apodictically Correct

    OpenAIRE

    Redford, James

    2011-01-01

    James Redford, "Libertarian Anarchism Is Apodictically Correct", Social Science Research Network (SSRN), Dec. 15, 2011, 9 pp., doi:10.2139/ssrn.1972733. ABSTRACT: It is shown that libertarian anarchism (i.e., consistent liberalism) is unavoidably true.

  12. Vieillissement du polyamide 11 utilisé dans les conduites flexibles : influence de la composition du fluide transporté Influence of the Chemical Nature of the Environment on the Aging of Polyamide 11 Used for Offshore Flexible Pipes

    Directory of Open Access Journals (Sweden)

    Ubrich E.

    2006-11-01

    émontrée et a pu être attribuée à certains types d'hydrocarbures dont la nature a été précisée. Les résultats obtenus ont permis de conclure que le phénomène principal mis en jeu au cours du vieillissement est une hydrolyse causée par l'eau absorbée dans le matériau et qui entraîne une coupure des chaînes macromoléculaires et la fragilisation du polymère. 3 D'étendre l'application du modèle établi avec des coupes gazoles au cas d'un vieillissement dans un pétrole brut et de vérifier son caractère prédictif. Polyamide 11 is used as a leakproof sheath inside flexible flowlines for petroleum products. Under some operating conditions, this polymer undergoes a degradation of its original physicochemical and mechanical properties, which may be assimilated with a phenomenon of aging. Material exchanges occur between polyamide 11 and the fluid transported. The components present in the fluid (water, hydrocarbons may be absorbed, and the principal additive of the material (the plasticizer is extracted. This study was carried out to determine the influence of the composition of the chemical environment of aging on the properties of polyamide 11. In the first phase, a new analysis method was developed for quantifying diffusing materials in polyamide 11. Effectively, several techniques can be used for determining such materials. However, interference problems may be encountered when the polymer is in contact with oil containing sulfur-bearing products. Likewise, none of these techniques is capable of simultaneously making a complete analysis of all the materials. The principle of the method developed consists in performing a thermodesorption of the different materials present in the polymer and in analyzing them on line by medium-resolution mass spectrometry (resolution = 3000. This resolution is also capable of determining the distribution, by chemical families, of the hydrocarbons absorbed. The method was checked with aged polyamide 11 samples containing either

  13. Corrective Action Investigation Plan for Corrective Action Unit 374: Area 20 Schooner Unit Crater Nevada Test Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Matthews

    2010-02-01

    Corrective Action Unit 374 is located in Areas 18 and 20 of the Nevada Test Site, which is approximately 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 374 comprises the five corrective action sites (CASs) listed below: • 18-22-05, Drum • 18-22-06, Drums (20) • 18-22-08, Drum • 18-23-01, Danny Boy Contamination Area • 20-45-03, U-20u Crater (Schooner) These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives (CAAs). Additional information will be obtained by conducting a corrective action investigation before evaluating CAAs and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable CAAs that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on October 20, 2009, by representatives of the Nevada Division of Environmental Protection and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 374.

  14. Error correcting coding for OTN

    DEFF Research Database (Denmark)

    Justesen, Jørn; Larsen, Knud J.; Pedersen, Lars A.

    2010-01-01

    Forward error correction codes for 100 Gb/s optical transmission are currently receiving much attention from transport network operators and technology providers. We discuss the performance of hard decision decoding using product type codes that cover a single OTN frame or a small number...... of such frames. In particular we argue that a three-error correcting BCH is the best choice for the component code in such systems....

  15. Beam Trajectory Correction for SNS

    CERN Document Server

    Chu, Chungming

    2005-01-01

    Automated beam trajectory correction with dipole correctors is developed and tested during the Spallation Neutron Source warm linac commissioning periods. The application is based on the XAL Java framework with newly developed optimization tools. Also, dipole corrector polarities and strengths, and beam position monitor (BPM) polarities were checked by an orbit difference program. The on-line model is used in both the trajectory correction and the orbit difference applications. Experimental data for both applications will be presented.

  16. Quantum error correction for beginners

    Science.gov (United States)

    Devitt, Simon J.; Munro, William J.; Nemoto, Kae

    2013-07-01

    Quantum error correction (QEC) and fault-tolerant quantum computation represent one of the most vital theoretical aspects of quantum information processing. It was well known from the early developments of this exciting field that the fragility of coherent quantum systems would be a catastrophic obstacle to the development of large-scale quantum computers. The introduction of quantum error correction in 1995 showed that active techniques could be employed to mitigate this fatal problem. However, quantum error correction and fault-tolerant computation is now a much larger field and many new codes, techniques, and methodologies have been developed to implement error correction for large-scale quantum algorithms. In response, we have attempted to summarize the basic aspects of quantum error correction and fault-tolerance, not as a detailed guide, but rather as a basic introduction. The development in this area has been so pronounced that many in the field of quantum information, specifically researchers who are new to quantum information or people focused on the many other important issues in quantum computation, have found it difficult to keep up with the general formalisms and methodologies employed in this area. Rather than introducing these concepts from a rigorous mathematical and computer science framework, we instead examine error correction and fault-tolerance largely through detailed examples, which are more relevant to experimentalists today and in the near future.

  17. Chemical safety: asking the right questions

    Energy Technology Data Exchange (ETDEWEB)

    Whyte, Helena M [Los Alamos National Laboratory; Quigley, David [Y-12/NSC; Simmons, Fred [SRS; Freshwater, David [DOE/NNSA; Robertson, Janeen [LLNL

    2008-01-01

    Recent reports have shown that, despite efforts to the contrary, chemical accidents continue to occur at an unacceptable rate and there is no evidence that this rate is decreasing. Based on this observation, one can conclude that previous analyses have not accurately identified and implemented appropriate fixes to eliminate identified root causes for chemical events. Based on this, it is time to reevaluate chemical accident data with a fresh eye and determine (a) what corrective actions have already been identified but have not been implemented, (b) what other root causes may be involved, and (c) what new corrective actions should be taken to eliminate these newly identified root causes.

  18. Natural product as a source of prodrug

    Directory of Open Access Journals (Sweden)

    Jagannathan Padmavathy

    2017-06-01

    Full Text Available The natural products are the chemical constituents that are generated from the living organism. The natural products are isolated from the plants, animals, and microorganisms which are used in drug design and drug discovery. Natural product is then modified by chemical synthesis as either total or semi-synthetic way. The natural products show various pharmacological activity which can be used for the treatment of a variety of diseases. Natural products could be regarded as a source of quantifiable and chemically pure known products and also natural products can be utilized as complex mixtures subjected to chemical variability. The present review article adds up the prodrugs from natural products as well as prodrugs developed from the natural products.

  19. Hazardous Chemicals

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

    Chemicals are a part of our daily lives, providing many products and modern conveniences. With more than three decades of experience, The Centers for Disease Control and Prevention (CDC) has been in the forefront of efforts to protect and assess people's exposure to environmental and hazardous chemicals. This report provides information about hazardous chemicals and useful tips on how to protect you and your family from harmful exposure.  Created: 4/10/2007 by CDC National Center for Environmental Health.   Date Released: 4/13/2007.

  20. Mitral Valve Repair: The French Correction Versus the American Correction.

    Science.gov (United States)

    Schubert, Sarah A; Mehaffey, James H; Charles, Eric J; Kron, Irving L

    2017-08-01

    Degenerative mitral valve disease causing mitral regurgitation is the most common organic valve pathology and is classified based on leaflet motion. The "French correction" mitral valve repair method restores normal valvular anatomy with extensive leaflet resection, chordal manipulation, and rigid annuloplasty. The American correction attempts to restore normal valve function through minimal leaflet resection, flexible annuloplasty, and use of artificial chordae. These differing methods of mitral valve repair reflect an evolution in principles, but both require understanding of the valve pathology and correction of leaflet prolapse and annular dilatation. Adhering to those unifying principles and ensuring that no patient leaves the operating room with significant persistent mitral regurgitation produces durable results and satisfactory patient outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Chemical Peel

    Science.gov (United States)

    ... complications in chemical peeling. Journal of Cutaneous and Aesthetic Surgery. 2010;3:186. Langsdon PR, et al. ... Discovery's Edge Magazine Search Publications Training Grant Positions Education Mayo Clinic College of Medicine and Science Mayo ...

  2. Chemical carcinogens

    National Research Council Canada - National Science Library

    Searle, Charles E

    1976-01-01

    Cancer causing agents are now known to exist throughout the environment-in polluted air and tobacco smoke, in various plants and foods, and in many chemicals that are used in industry and laboratories...

  3. Chemical Carcinogenesis

    OpenAIRE

    Oliveira, Paula A.; Aura Colaço; Raquel Chaves; Henrique Guedes-Pinto; Luis F. De-La-Cruz P.; Carlos Lopes

    1980-01-01

    The use of chemical compounds benefits society in a number of ways. Pesticides, for instance, enable foodstuffs to be produced in sufficient quantities to satisfy the needs of millions of people, a condition that has led to an increase in levels of life expectancy. Yet, at times, these benefits are offset by certain disadvantages, notably the toxic side effects of the chemical compounds used. Exposure to these compounds can have varying effects, ranging from instant death to a gradual process...

  4. The relativistic Scott correction for atoms and molecules

    DEFF Research Database (Denmark)

    Solovej, Jan Philip; Sørensen, Thomas Østergaard; Spitzer, Wolfgang L.

    We prove the first correction to the leading Thomas-Fermi energy for the ground state energy of atoms and molecules in a model where the kinetic energy of the electrons is treated relativistically. The leading Thomas-Fermi energy, established in [25], as well as the correction given here are of s......We prove the first correction to the leading Thomas-Fermi energy for the ground state energy of atoms and molecules in a model where the kinetic energy of the electrons is treated relativistically. The leading Thomas-Fermi energy, established in [25], as well as the correction given here...... are of semi-classical nature. Our result on atoms and molecules is proved from a general semi-classical estimate for relativistic operators with potentials with Coulomb-like singularities. This semi-classical estimate is obtained using the coherent state calculus introduced in [36]. The paper contains...

  5. Physical nature of interactions in Zn(II) complexes with 2,2'-bipyridyl: quantum theory of atoms in molecules (QTAIM), interacting quantum atoms (IQA), noncovalent interactions (NCI), and extended transition state coupled with natural orbitals for chemical valence (ETS-NOCV) comparative studies.

    Science.gov (United States)

    Cukrowski, Ignacy; de Lange, Jurgens H; Mitoraj, Mariusz

    2014-01-23

    In the present account factors determining the stability of ZnL, ZnL2, and ZnL3 complexes (L = bpy, 2,2′-bipyridyl) were characterized on the basis of various techniques: the quantum theory of atoms in molecules (QTAIM), energy decomposition schemes based on interacting quantum atoms (IQA), and extended transition state coupled with natural orbitals for chemical valence (ETS-NOCV). Finally, the noncovalent interactions (NCI) index was also applied. All methods consistently indicated that the strength of the coordination bonds, Zn–O and Zn–N, decreases from ZnL to ZnL3. Importantly, it has been identified that the strength of secondary intramolecular heteropolar hydrogen bonding interactions, CH···O and CH···N, increases when going from ZnL to ZnL3. A similar trend appeared to be valid for the π-bonding as well as electrostatic stabilization. In addition to the above leading bonding contributions, all techniques suggested the existence of very subtle, but non-negligible additional stabilization from the CH···HC electronic exchange channel; these interactions are the weakest among all considered here. From IQA it was found that the local diatomic interaction energy, Eint(H,H), amounts at HF to −2.5, −2.7, and −2.9 kcal mol(–1) for ZnL, ZnL2, and ZnL3, respectively (−2.1 kcal mol(–1) for ZnL at MP2). NOCV-based deformation density channels showed that formation of CH--HC contacts in Zn complexes causes significant polarization of σ(C–H) bonds, which accordingly leads to charge accumulation in the CH···HC bay region. Charge depletion from σ(C–H) bonds was also reflected in the calculated spin–spin (1)J(C–H) coupling constants, which decrease from 177.06 Hz (ZnL) to 173.87 Hz (ZnL3). This last result supports our findings of an increase in the local electronic CH···HC stabilization from ZnL to ZnL3 found from QTAIM, IQA, and ETS-NOCV. Finally, this work unites for the first time the results from four methods that are widely

  6. PLURALIZING NATURE

    DEFF Research Database (Denmark)

    Clemmensen, Thomas Juel

    2014-01-01

    not necessary mean planning for a one common nature. As exemplified by the River Aire Re-naturalization Project (2002-2015), landscape architecture might provide an alternative approach to nature restoration that is more site specific and allows for multiple interpretations to coexist. In the presentation...

  7. The role of error correction in communicative second language teaching

    Directory of Open Access Journals (Sweden)

    H. Ludolph Botha

    2013-02-01

    Full Text Available According to recent rese~rch, correction of errors in both oral and written communication does little to a~d language proficiency in the second language. In the Natural Approach of Krashen and Terrell the emphasis is on the acquisition of informal communication. Because the message and the understanding of the message remain of utmost importance, error correction is avoided. In Suggestopedia where the focus is also on communication, error correction is avoided as it inhibits the pupil. Onlangse navorsing het getoon dat die verbetering van foute in beide mondelinge en skriftelike kommunikasie min bydra tot beter taalvaardigheid in die tweede taal. In die Natural Approach van Krashen en Terrell val die klem op die verwerwing van informele kommunikasie, want die boodskap en die verstaan daarvan bly verreweg die belangrikste; die verbetering van foute word vermy. In Suggestopedagogiek, waar die klem ook op kommunikasie val, word die verbetering van foute vermy omdat dit die leerling beperk.

  8. Dissemination of original NMR data enhances reproducibility and integrity in chemical research.

    Science.gov (United States)

    Bisson, Jonathan; Simmler, Charlotte; Chen, Shao-Nong; Friesen, J Brent; Lankin, David C; McAlpine, James B; Pauli, Guido F

    2016-08-25

    The notion of data transparency is gaining a strong awareness among the scientific community. The availability of raw data is actually regarded as a fundamental way to advance science by promoting both integrity and reproducibility of research outcomes. Particularly, in the field of natural product and chemical research, NMR spectroscopy is a fundamental tool for structural elucidation and quantification (qNMR). As such, the accessibility of original NMR data, i.e., Free Induction Decays (FIDs), fosters transparency in chemical research and optimizes both peer review and reproducibility of reports by offering the fundamental tools to perform efficient structural verification. Although original NMR data are known to contain a wealth of information, they are rarely accessible along with published data. This viewpoint discusses the relevance of the availability of original NMR data as part of good research practices not only to promote structural correctness, but also to enhance traceability and reproducibility of both chemical and biological results.

  9. Chemical carcinogenesis.

    Science.gov (United States)

    Oliveira, Paula A; Colaço, Aura; Chaves, Raquel; Guedes-Pinto, Henrique; De-La-Cruz P, Luis F; Lopes, Carlos

    2007-12-01

    The use of chemical compounds benefits society in a number of ways. Pesticides, for instance, enable foodstuffs to be produced in sufficient quantities to satisfy the needs of millions of people, a condition that has led to an increase in levels of life expectancy. Yet, at times, these benefits are offset by certain disadvantages, notably the toxic side effects of the chemical compounds used. Exposure to these compounds can have varying effects, ranging from instant death to a gradual process of chemical carcinogenesis. There are three stages involved in chemical carcinogenesis. These are defined as initiation, promotion and progression. Each of these stages is characterised by morphological and biochemical modifications and result from genetic and/or epigenetic alterations. These genetic modifications include: mutations in genes that control cell proliferation, cell death and DNA repair--i.e. mutations in proto-oncogenes and tumour suppressing genes. The epigenetic factors, also considered as being non-genetic in character, can also contribute to carcinogenesis via epigenetic mechanisms which silence gene expression. The control of responses to carcinogenesis through the application of several chemical, biochemical and biological techniques facilitates the identification of those basic mechanisms involved in neoplasic development. Experimental assays with laboratory animals, epidemiological studies and quick tests enable the identification of carcinogenic compounds, the dissection of many aspects of carcinogenesis, and the establishment of effective strategies to prevent the cancer which results from exposure to chemicals.

  10. Corrective Action Investigation Plan for Corrective Action Unit 447: Project Shoal Area, Nevada Subsurface Site

    Energy Technology Data Exchange (ETDEWEB)

    DOE/NV

    1998-11-01

    This Corrective Action Investigation Plan (CAIP) describes the US Department of Energy's (DOE's) continued environmental investigation of the subsurface Project Shoal Area (PSA) Corrective Action Unit (CAU) 447. The PSA is located in the Sand Springs Mountains in Churchill County, Nevada, about 48 kilometers (km) (30 miles [mi]) southeast of Fallon, Nevada. Project Shoal was part of the Vela Uniform Program which was conducted to improve the US' ability to detect, identify, and locate underground nuclear detonations. The test consisted of detonating a 12-kiloton nuclear device deep underground in granitic rock to determine whether seismic waves produced by an underground nuclear test could be differentiated from seismic waves produced by a naturally occurring earthquake. The test was a joint effort conducted by the US Atomic Energy Commission (AEC) and the US Department of Defense (DoD) in October 1963 (AEC, 1964).

  11. Corrective Action Investigation Plan for Corrective Action Unit 139: Waste Disposal Sites, Nevada Test Site, Nevada, Rev. No.: 0

    Energy Technology Data Exchange (ETDEWEB)

    Grant Evenson

    2006-04-01

    Corrective Action Unit (CAU) 139 is located in Areas 3, 4, 6, and 9 of the Nevada Test Site, which is 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 139 is comprised of the seven corrective action sites (CASs) listed below: (1) 03-35-01, Burn Pit; (2) 04-08-02, Waste Disposal Site; (3) 04-99-01, Contaminated Surface Debris; (4) 06-19-02, Waste Disposal Site/Burn Pit; (5) 06-19-03, Waste Disposal Trenches; (6) 09-23-01, Area 9 Gravel Gertie; and (7) 09-34-01, Underground Detection Station. These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives with the exception of CASs 09-23-01 and 09-34-01. Regarding these two CASs, CAS 09-23-01 is a gravel gertie where a zero-yield test was conducted with all contamination confined to below ground within the area of the structure, and CAS 09-34-01 is an underground detection station where no contaminants are present. Additional information will be obtained by conducting a corrective action investigation (CAI) before evaluating corrective action alternatives and selecting the appropriate corrective action for the other five CASs where information is insufficient. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on January 4, 2006, by representatives of the Nevada Division of Environmental Protection; U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office; Stoller-Navarro Joint Venture; and Bechtel Nevada. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 139.

  12. Effect of chemical heterogeneity of biodegradable polymers on surface energy: A static contact angle analysis of polyester model films

    Energy Technology Data Exchange (ETDEWEB)

    Belibel, R.; Avramoglou, T. [INSERM U1148, Laboratory for Vascular Translational Science (LVTS), Institut Galilée, Université Paris 13, Sorbonne Paris Cité, 99 Avenue Jean-Baptiste Clément, Villetaneuse F-93430 (France); Garcia, A. [CNRS UPR 3407, Laboratoire des Sciences des Procédés et des Matériau, Institut Galilée, Université Paris 13, Sorbonne Paris Cité, 99 Avenue Jean-Baptiste Clément, Villetaneuse F-93430 (France); Barbaud, C. [INSERM U1148, Laboratory for Vascular Translational Science (LVTS), Institut Galilée, Université Paris 13, Sorbonne Paris Cité, 99 Avenue Jean-Baptiste Clément, Villetaneuse F-93430 (France); Mora, L., E-mail: Laurence.mora@univ-paris13.fr [INSERM U1148, Laboratory for Vascular Translational Science (LVTS), Institut Galilée, Université Paris 13, Sorbonne Paris Cité, 99 Avenue Jean-Baptiste Clément, Villetaneuse F-93430 (France)

    2016-02-01

    Biodegradable and bioassimilable poly((R,S)-3,3 dimethylmalic acid) (PDMMLA) derivatives were synthesized and characterized in order to develop a new coating for coronary endoprosthesis enabling the reduction of restenosis. The PDMMLA was chemically modified to form different custom groups in its side chain. Three side groups were chosen: the hexyl group for its hydrophobic nature, the carboxylic acid and alcohol groups for their acid and neutral hydrophilic character, respectively. The sessile drop method was applied to characterize the wettability of biodegradable polymer film coatings. Surface energy and components were calculated. The van Oss approach helped reach not only the dispersive and polar acid–base components of surface energy but also acid and basic components. Surface topography was quantified by atomic force microscopy (AFM) and subnanometer average values of roughness (Ra) were obtained for all the analyzed surfaces. Thus, roughness was considered to have a negligible effect on wettability measurements. In contrast, heterogeneous surfaces had to be corrected by the Cassie–Baxter equation for copolymers (10/90, 20/80 and 30/70). The impact of this correction was quantified for all the wettability parameters. Very high relative corrections (%) were found, reaching 100% for energies and 30% for contact angles. - Highlights: • We develop different polymers with various chemical compositions. • Wettability properties were calculated using Cassie corrected contact angles. • Percentage of acid groups in polymers is directly correlated to acid part of SFE. • Cassie corrections are necessary for heterogeneous polymers.

  13. Correction

    Directory of Open Access Journals (Sweden)

    Laergaard Simon

    1996-11-01

    Full Text Available In the paper Muhlenbergia cleefii sp.nov., a new grass from the high Andes of Colombia, Caldasia 17(82-85: 409-412. 1995, an orthographic error was unfortunately introduced and the epithet was speIled "cleefi" (except at one place in the general text.

  14. Correction.

    Science.gov (United States)

    2015-03-01

    In the January 2015 issue of Cyberpsychology, Behavior, and Social Networking (vol. 18, no. 1, pp. 3–7), the article "Individual Differences in Cyber Security Behaviors: An Examination of Who Is Sharing Passwords." by Prof. Monica Whitty et al., has an error in wording in the abstract. The sentence in question was originally printed as: Contrary to our hypotheses, we found older people and individuals who score high on self-monitoring were more likely to share passwords. It should read: Contrary to our hypotheses, we found younger people and individuals who score high on self-monitoring were more likely to share passwords. The authors wish to apologize for the error.

  15. Correction

    Science.gov (United States)

    1999-11-01

    Synsedimentary deformation in the Jurassic of southeastern Utah—A case of impact shaking? COMMENT Geology, v. 27, p. 661 (July 1999) The sentence on p. 661, first column, second paragraph, line one, should read: The 1600 m of Pennsylvania Paradox Formation is 75 90% salt in Arches National Park. The sentence on p. 661, second column, third paragraph, line seven, should read: This high-pressured ydrothermal solution created the clastic dikes, chert nodules from reprecipitated siliceous cement that have been called “siliceous impactites” (Kriens et al., 1997), and much of the present structure at Upheaval Dome by further faulting.

  16. Correction

    CERN Document Server

    2007-01-01

    From left to right: Luis, Carmen, Mario, Christian and José listening to speeches by theorists Alvaro De Rújula and Luis Alvarez-Gaumé (right) at their farewell gathering on 15 May.We unfortunately cut out a part of the "Word of thanks" from the team retiring from Restaurant No. 1. The complete message is published below: Dear friends, You are the true "nucleus" of CERN. Every member of this extraordinary human mosaic will always remain in our affections and in our thoughts. We have all been very touched by your spontaneous generosity. Arrivederci, Mario Au revoir,Christian Hasta Siempre Carmen, José and Luis PS: Lots of love to the theory team and to the hidden organisers. So long!

  17. String-Corrected Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Hubeny, V.

    2005-01-12

    We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect--the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive. The magnitude of this effect is related to the size of the compactification manifold.

  18. Should diastasis recti be corrected?

    Science.gov (United States)

    Nahas, F X; Augusto, S M; Ghelfond, C

    1997-01-01

    The plication of the anterior rectus sheath is a procedure that is performed by most surgeons during abdominoplasty. A main concern is whether the correction of recti diastasis is really effective and if it is stable. In order to verify the position of the rectus muscle, a CT-scan was used in 14 patients who underwent abdominoplasty with rectus plication to compare the preoperative situation of these muscles with their position 3 weeks and 6 months postoperatively. None of these patients had had previous abdominal surgery. The recti diastasis was corrected with a two-layer 2-0 Nylon suture. A dynamometer was used to measure the resistance force of the anterior aponeurosis of the rectus. In all cases the CT data shows that correction of the diastasis was achieved completely after 6 months.

  19. Delegation in Correctional Nursing Practice.

    Science.gov (United States)

    Tompkins, Frances

    2016-07-01

    Correctional nurses face daily challenges as a result of their work environment. Common challenges include availability of resources for appropriate care delivery, negotiating with custody staff for access to patients, adherence to scope of practice standards, and working with a varied staffing mix. Professional correctional nurses must consider the educational backgrounds and competency of other nurses and assistive personnel in planning for care delivery. Budgetary constraints and varied staff preparation can be a challenge for the professional nurse. Adequate care planning requires understanding the educational level and competency of licensed and unlicensed staff. Delegation is the process of assessing patient needs and transferring responsibility for care to appropriately educated and competent staff. Correctional nurses can benefit from increased knowledge about delegation. © The Author(s) 2016.

  20. "LEPTOP" electroweak corrections at LEP1

    CERN Document Server

    Novikov, V; Vysotsky, M I

    1995-01-01

    This work discusses parameters of the electroweak Lagrangian, coupling constants, the alpha Born approximation, W mass, Z mass, Z decays, one-loop electroweak corrections, electroweak corrections for the "gluon-free" observables, gluonic corrections to electroweak loops. (12 refs).