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Sample records for chemically diverse analytes

  1. Separation and Quantification of Chemically Diverse Analytes in Neutron Irradiated Fissile Materials

    SciTech Connect

    Douglas, Matthew; Friese, Judah I.; Greenwood, Lawrence R.; Farmer, Orville T.; Thomas, Linda MP; Maiti, Tapas C.; Finn, Erin C.; Garofoli, Stephanie J.; Gassman, Paul L.; Huff, Morgan M.; Schulte, Shannon M.; Smith, Steven C.; Thomas, Kathie K.; Bachelor, Paula P.

    2009-10-01

    Quantitative measurement of fission and activation products resulting from neutron irradiation of fissile materials is of interest for applications in environmental monitoring, nuclear waste management, and national security. To overcome mass and spectral interferences, and the relative small quantities of some target analytes, an extensive series of chemical separations is necessary. Based on established separations processes involving co-precipitation, solvent extraction, and ion-exchange and extraction chromatography, we have been evaluating and optimizing a proposed sequence of separation steps to allow for the timely quantification of analytes of interest. For simplicity, much of the chemical separation development work has been performed using stable elements as surrogates for the radioactive material. We have recently evaluated the optimized procedures using an irradiated sample to examine the adequacy of separations for measurement of desired analytes by gamma spectrometry. Here we present the results of this evaluation and describe the radiochemical separations utilized.

  2. Sensor for detecting and differentiating chemical analytes

    DOEpatents

    Yi, Dechang; Senesac, Lawrence R.; Thundat, Thomas G.

    2011-07-05

    A sensor for detecting and differentiating chemical analytes includes a microscale body having a first end and a second end and a surface between the ends for adsorbing a chemical analyte. The surface includes at least one conductive heating track for heating the chemical analyte and also a conductive response track, which is electrically isolated from the heating track, for producing a thermal response signal from the chemical analyte. The heating track is electrically connected with a voltage source and the response track is electrically connected with a signal recorder. The microscale body is restrained at the first end and the second end and is substantially isolated from its surroundings therebetween, thus having a bridge configuration.

  3. Aquatic concentrations of chemical analytes compared to ...

    EPA Pesticide Factsheets

    We describe screening level estimates of potential aquatic toxicity posed by 227 chemical analytes that were measured in 25 ambient water samples collected as part of a joint USGS/USEPA drinking water plant study. Measured concentrations were compared to biological effect concentration (EC) estimates, including USEPA aquatic life criteria, effective plasma concentrations of pharmaceuticals, published toxicity data summarized in the USEPA ECOTOX database, and chemical structure-based predictions. Potential dietary exposures were estimated using a generic 3-tiered food web accumulation scenario. For many analytes, few or no measured effect data were found, and for some analytes, reporting limits exceeded EC estimates, limiting the scope of conclusions. Results suggest occasional occurrence above ECs for copper, aluminum, strontium, lead, uranium, and nitrate. Sparse effect data for manganese, antimony, and vanadium suggest that these analytes may occur above ECs, but additional effect data would be desirable to corroborate EC estimates. These conclusions were not affected by bioaccumulation estimates. No organic analyte concentrations were found to exceed EC estimates, but ten analytes had concentrations in excess of 1/10th of their respective EC: triclocarban, norverapamil, progesterone, atrazine, metolachlor, triclosan, para-nonylphenol, ibuprofen, venlafaxine, and amitriptyline, suggesting more detailed characterization of these analytes. Purpose: to provide sc

  4. Big Data Analytics in Chemical Engineering.

    PubMed

    Chiang, Leo; Lu, Bo; Castillo, Ivan

    2017-02-27

    Big data analytics is the journey to turn data into insights for more informed business and operational decisions. As the chemical engineering community is collecting more data (volume) from different sources (variety), this journey becomes more challenging in terms of using the right data and the right tools (analytics) to make the right decisions in real time (velocity). This article highlights recent big data advancements in five industries, including chemicals, energy, semiconductors, pharmaceuticals, and food, and then discusses technical, platform, and culture challenges. To reach the next milestone in multiplying successes to the enterprise level, government, academia, and industry need to collaboratively focus on workforce development and innovation. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering Volume 8 is June 7, 2017. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  5. Analytic considerations for measuring environmental chemicals in breast milk.

    PubMed Central

    Needham, Larry L; Wang, Richard Y

    2002-01-01

    The presence of environmental chemicals in human breast milk is of general concern because of the potential health consequence of these chemicals to the breast-fed infant and the mother. In addition to the mother's exposure, several features determine the presence of environmental chemicals in breast milk and their ability to be determined analytically. These include maternal factors and properties of the environmental chemical--both physical and chemical--such as its lipid solubility, degree of ionization, and molecular weight. Environmental chemicals with high lipid solubility are likely to be found in breast milk; they include polyhalogenated compounds such as polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, organochlorine insecticides, and polybrominated diphenylethers. These fat-soluble chemicals are incorporated into the milk as it is synthesized, and they must be measured in accordance with the fat content of the milk to allow for meaningful comparisons within an individual and among populations. Although the analytic approach selected to measure the environmental chemical is predominantly determined by the characteristics of the chemical, the concentration of the chemical in the milk sample and the existence of structurally similar chemicals (e.g., congeners) must be considered as well. In general, the analytic approach for measuring environmental chemicals in breast milk is similar to the approach for measuring the same chemicals in other matrices, except special considerations must be given for the relatively high fat content of milk. The continued efforts of environmental scientists to measure environmental chemicals in breast milk is important for defining the true contribution of these chemicals to public health, especially to the health of the newborn. Work is needed for identifying and quantifying additional environmental chemicals in breast milk from the general population and for developing analytic

  6. Importance of analytically verifying chemical treatments

    USGS Publications Warehouse

    Rach, J.J.; Gaikowski, M.P.; Olson, J.J.

    1997-01-01

    Hydrogen peroxide is considered a low regulatory priority compound by the U.S. Food and Drug Administration. It is used to control fungal infections on fish eggs. We studied the treatment profiles of hydrogen peroxide in Heath, McDonald egg jar, and Clark-Williamson incubators during treatments intended to deliver an effective regimen of at least 500 ??L hydrogen peroxide/L (i.e., treatments of 500 and 1,000 ??L/L) for 15 min. Hydrogen peroxide concentrations decreased with increasing distance from the influent water in both Heath and Clark-Williamson incubators. The top treatment tray (tray 2) of the Heath incubator received more than 90% of the intended regimen during the 500 ??L/L treatment, whereas at 1,000 ??L/L, all trays had hydrogen peroxide concentrations at or above 500 ??L/L for 15 min. None of the compartments in the Clark-Williamson incubator received the intended therapeutic regimen when treated at 500 ??L/L. The McDonald egg jar system distributed the intended concentration for the designated treatment period in all jars, except those located directly below the influent water. Our results indicate that dilution of therapeutants applied through certain egg incubation systems significantly decreases the efficacy of treatments and may render them ineffective. The dilution characteristics of egg incubation systems should be assessed in order to ensure proper delivery of all intended chemical concentrations and exposure regimens. Suggestions for maintaining the minimum effective concentrations in evaluated incubators are included.

  7. Analytical formulation of chemical derivatives in equilibrium plasma flows.

    PubMed

    Orsini, Alessio

    2008-12-01

    Chemical derivatives are used in the mathematical modeling of transport phenomena in equilibrium plasma flows when chemical element diffusion and mixing or demixing effects are accounted for. They measure the variation of mixture chemical composition in response to changes in element fractions, pressure, or temperature. Currently, these quantities are calculated numerically, using finite differences. This approach, other than being computationally expensive and prone to numerical error, does not provide any insight into flow physics. Our work is aimed at introducing a fully analytical method for the calculation of chemical derivatives which bypasses the computational cost. It also provides a simple means of estimating their order of magnitude.

  8. Aquatic concentrations of chemical analytes compared to ecotoxicity estimates

    EPA Science Inventory

    We describe screening level estimates of potential aquatic toxicity posed by 227 chemical analytes that were measured in 25 ambient water samples collected as part of a joint USGS/USEPA drinking water plant study. Measured concentrations were compared to biological effect concent...

  9. One species, many terpenes: matching chemical and biological diversity.

    PubMed

    Loreto, Francesco; Bagnoli, Francesca; Fineschi, Silvia

    2009-08-01

    Volatile terpenes have been proposed as chemotaxonomic markers, despite the strong environmental control on their synthesis. To clarify whether chemical profiles match biological diversity, cork oak, a monoterpene-emitting species that has been bred by humans and frequently hybridizes with other oaks, is a useful case-study. Analysis of the available genetic information in cork oak provenances suggests that volatile terpenes might indeed suitably track geographical diversity even at the intraspecific level. Phylogeographical diversity does not reflect chemical diversity in other evergreen oaks that have not been intensively bred. Breeding for productive traits might therefore drive selection for terpene diversity, in turn modulating important adaptive mechanisms against biotic and abiotic stressors.

  10. Analytical methods applied to diverse types of Brazilian propolis

    PubMed Central

    2011-01-01

    Propolis is a bee product, composed mainly of plant resins and beeswax, therefore its chemical composition varies due to the geographic and plant origins of these resins, as well as the species of bee. Brazil is an important supplier of propolis on the world market and, although green colored propolis from the southeast is the most known and studied, several other types of propolis from Apis mellifera and native stingless bees (also called cerumen) can be found. Propolis is usually consumed as an extract, so the type of solvent and extractive procedures employed further affect its composition. Methods used for the extraction; analysis the percentage of resins, wax and insoluble material in crude propolis; determination of phenolic, flavonoid, amino acid and heavy metal contents are reviewed herein. Different chromatographic methods applied to the separation, identification and quantification of Brazilian propolis components and their relative strengths are discussed; as well as direct insertion mass spectrometry fingerprinting. Propolis has been used as a popular remedy for several centuries for a wide array of ailments. Its antimicrobial properties, present in propolis from different origins, have been extensively studied. But, more recently, anti-parasitic, anti-viral/immune stimulating, healing, anti-tumor, anti-inflammatory, antioxidant and analgesic activities of diverse types of Brazilian propolis have been evaluated. The most common methods employed and overviews of their relative results are presented. PMID:21631940

  11. Analytic models of the chemical evolution of galaxies

    NASA Technical Reports Server (NTRS)

    Clayton, Donald D.

    1986-01-01

    Techniques are described for constructing analytic models of the chemical evolution of galaxies subject to infall of metal-poor material onto a maturing disk. A class of linear models is discussed which takes the star-formation rate within a defined region to be proportional to the mass of interstellar gas within that region, and the instantaneous recycling approximation is adopted. The solutions are obtained by approximately matching the infall rate to parametrized familiies of functions for which the equations are exactly soluble. The masses, the primary and secondary metallicities, and the gas concentrations of radioactive chronometers can all then be analytically expressed. Surveys of galactic abundances in location and in time can be compared to the parameter spaces of the analytic representations.

  12. A Decision Analytic Approach to Exposure-Based Chemical ...

    EPA Pesticide Factsheets

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient data are available, the hazard and exposure data necessary to assess risks adequately are unavailable for the vast majority of chemicals in commerce. The US Environmental Protection Agency has initiated the ExpoCast Program to develop tools for rapid chemical evaluation based on potential for exposure. In this context, a model is presented in which chemicals are evaluated based on inherent chemical properties and behaviorally-based usage characteristics over the chemical’s life cycle. These criteria are assessed and integrated within a decision analytic framework, facilitating rapid assessment and prioritization for future targeted testing and systems modeling. A case study outlines the prioritization process using 51 chemicals. The results show a preliminary relative ranking of chemicals based on exposure potential. The strength of this approach is the ability to integrate relevant statistical and mechanistic data with expert judgment, allowing for an initial tier assessment that can further inform targeted testing and risk management strategies. The National Exposure Research Laboratory′s (NERL′s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in suppor

  13. A Decision Analytic Approach to Exposure-Based Chemical Prioritization

    PubMed Central

    Mitchell, Jade; Pabon, Nicolas; Collier, Zachary A.; Egeghy, Peter P.; Cohen-Hubal, Elaine; Linkov, Igor; Vallero, Daniel A.

    2013-01-01

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient data are available, the hazard and exposure data necessary to assess risks adequately are unavailable for the vast majority of chemicals in commerce. The US Environmental Protection Agency has initiated the ExpoCast Program to develop tools for rapid chemical evaluation based on potential for exposure. In this context, a model is presented in which chemicals are evaluated based on inherent chemical properties and behaviorally-based usage characteristics over the chemical’s life cycle. These criteria are assessed and integrated within a decision analytic framework, facilitating rapid assessment and prioritization for future targeted testing and systems modeling. A case study outlines the prioritization process using 51 chemicals. The results show a preliminary relative ranking of chemicals based on exposure potential. The strength of this approach is the ability to integrate relevant statistical and mechanistic data with expert judgment, allowing for an initial tier assessment that can further inform targeted testing and risk management strategies. PMID:23940664

  14. Analytical Chemical Sensing in the Submillimeter/terahertz Spectral Range

    NASA Astrophysics Data System (ADS)

    Moran, Benjamin L.; Fosnight, Alyssa M.; Medvedev, Ivan R.; Neese, Christopher F.

    2012-06-01

    Highly sensitive and selective Terahertz sensor utilized to quantitatively analyze a complex mixture of Volatile Organic Compounds is reported. To best demonstrate analytical capabilities of THz chemical sensors we chose to perform analytical quantitative analysis of a certified gas mixture using a novel prototype chemical sensor that couples a commercial preconcentration system (Entech 7100A) to a high resolution THz spectrometer. We selected Method TO-14A certified mixture of 39 volatile organic compounds (VOCs) diluted to 1 part per million (ppm) in nitrogen. 26 of the 39 chemicals were identified by us as suitable for THz spectroscopic detection. Entech 7100A system is designed and marketed as an inlet system for Gas Chromatography-Mass Spectrometry (GC-MS) instruments with a specific focus on TO-14 and TO-15 EPA sampling methods. Its preconcentration efficiency is high for the 39 chemicals in the mixture used for this study and our preliminary results confirm this. Here we present the results of this study which serves as basis for our ongoing research in environmental sensing and analysis of exhaled human breath.

  15. Patterns of chemical diversity in the Mediterranean sponge Spongia lamella.

    PubMed

    Noyer, Charlotte; Thomas, Olivier P; Becerro, Mikel A

    2011-01-01

    The intra-specific diversity in secondary metabolites can provide crucial information for understanding species ecology and evolution but has received limited attention in marine chemical ecology. The complex nature of diversity is partially responsible for the lack of studies, which often target a narrow number of major compounds. Here, we investigated the intra-specific chemical diversity of the Mediterranean sponge Spongia lamella. The chemical profiles of seven populations spreading over 1200 km in the Western Mediterranean were obtained by a straightforward SPE-HPLC-DAD-ELSD process whereas the identity of compounds was assessed by comparison between HPLC-MS spectra and literature data. Chemical diversity calculated by richness and Shannon indexes differed significantly between sponge populations but not at a larger regional scale. We used factor analysis, analysis of variance, and regression analysis to examine the chemical variability of this sponge at local and regional scales, to establish general patterns of variation in chemical diversity. The abundance of some metabolites varied significantly between sponge populations. Despite these significant differences between populations, we found a clear pattern of increasing chemical dissimilarity with increasing geographic distance. Additional large spatial scale studies on the chemical diversity of marine organisms will validate the universality or exclusivity of this pattern.

  16. Patterns of Chemical Diversity in the Mediterranean Sponge Spongia lamella

    PubMed Central

    Noyer, Charlotte; Thomas, Olivier P.; Becerro, Mikel A.

    2011-01-01

    The intra-specific diversity in secondary metabolites can provide crucial information for understanding species ecology and evolution but has received limited attention in marine chemical ecology. The complex nature of diversity is partially responsible for the lack of studies, which often target a narrow number of major compounds. Here, we investigated the intra-specific chemical diversity of the Mediterranean sponge Spongia lamella. The chemical profiles of seven populations spreading over 1200 km in the Western Mediterranean were obtained by a straightforward SPE-HPLC-DAD-ELSD process whereas the identity of compounds was assessed by comparison between HPLC-MS spectra and literature data. Chemical diversity calculated by richness and Shannon indexes differed significantly between sponge populations but not at a larger regional scale. We used factor analysis, analysis of variance, and regression analysis to examine the chemical variability of this sponge at local and regional scales, to establish general patterns of variation in chemical diversity. The abundance of some metabolites varied significantly between sponge populations. Despite these significant differences between populations, we found a clear pattern of increasing chemical dissimilarity with increasing geographic distance. Additional large spatial scale studies on the chemical diversity of marine organisms will validate the universality or exclusivity of this pattern. PMID:21698108

  17. JOVIAN STRATOSPHERE AS A CHEMICAL TRANSPORT SYSTEM: BENCHMARK ANALYTICAL SOLUTIONS

    SciTech Connect

    Zhang Xi; Shia Runlie; Yung, Yuk L.

    2013-04-20

    We systematically investigated the solvable analytical benchmark cases in both one- and two-dimensional (1D and 2D) chemical-advective-diffusive systems. We use the stratosphere of Jupiter as an example but the results can be applied to other planetary atmospheres and exoplanetary atmospheres. In the 1D system, we show that CH{sub 4} and C{sub 2}H{sub 6} are mainly in diffusive equilibrium, and the C{sub 2}H{sub 2} profile can be approximated by modified Bessel functions. In the 2D system in the meridional plane, analytical solutions for two typical circulation patterns are derived. Simple tracer transport modeling demonstrates that the distribution of a short-lived species (such as C{sub 2}H{sub 2}) is dominated by the local chemical sources and sinks, while that of a long-lived species (such as C{sub 2}H{sub 6}) is significantly influenced by the circulation pattern. We find that an equator-to-pole circulation could qualitatively explain the Cassini observations, but a pure diffusive transport process could not. For slowly rotating planets like the close-in extrasolar planets, the interaction between the advection by the zonal wind and chemistry might cause a phase lag between the final tracer distribution and the original source distribution. The numerical simulation results from the 2D Caltech/JPL chemistry-transport model agree well with the analytical solutions for various cases.

  18. Role of natural product diversity in chemical biology.

    PubMed

    Hong, Jiyong

    2011-06-01

    Through the natural selection process, natural products possess a unique and vast chemical diversity and have been evolved for optimal interactions with biological macromolecules. Owing to their diversity, target affinity, and specificity, natural products have demonstrated enormous potential as modulators of biomolecular function, been an essential source for drug discovery, and provided design principles for combinatorial library development.

  19. Chemical diversity in the comet population

    NASA Astrophysics Data System (ADS)

    Biver, Nicolas; Bockelée-Morvan, Dominique

    2016-10-01

    For the last 3 decades, infrared and microwave techniques have enabled the detection of up to 27 parent molecules in the coma of comets. Several molecules have been detected in over 40 different comets. A large diversity of composition is seen in the sample, comprising comets of various dynamical origins. Abundances relative to water for the molecules can vary by a factor 3 to more than 10. The taxonomic study of a sample of comets in which the abundance of several molecules (e.g., HCN, CH3OH, CO, CH4, C2H6, H2S, H2CO, CH3CN, CS, . . .) has been measured does not show any clear grouping. Except for fragments of a common parent comet, every observed comet shows a different composition. The absence of any clear correlation between the volatile content of the comets and their dynamical origin (Kuiper Belt versus Oort Cloud) is consistent with a common origin for these two populations. Their diversity in composition may also suggest that radial and temporal mixing in the early proto-planetary nebula may have played an important role.

  20. Chemical Diversity in Basil (Ocimum sp.) Germplasm

    PubMed Central

    da Costa, Andréa Santos; Arrigoni-Blank, Maria de Fátima; de Carvalho Filho, José Luiz Sandes; de Santana, Aléa Dayane Dantas; Santos, Darlisson de Alexandria; Alves, Péricles Barreto; Blank, Arie Fitzgerald

    2015-01-01

    The present study aimed to chemically characterize 31 accessions and seven cultivars of basil. The percentage composition of the essential oils of the accessions and cultivars was based on the 14 most abundant constituents: 1,8-cineole, linalool, methyl chavicol, neral, nerol, geraniol, geranial, methyl cinnamate, β-bourbonene, methyl eugenol, α-trans-bergamotene, germacrene-D, epi-α-cadinol, and δ-cadinene. The genetic materials were classified into eight clusters according to the chemical composition of the essential oils: Cluster 1—mostly linalool and 1,8-cineole; Cluster 2—mostly linalool, geraniol, and α-trans-bergamotene; Cluster 3—mostly linalool, methyl chavicol, methyl cinnamate, and β-bourbonene; Cluster 4—mostly linalool, methyl chavicol, epi-α-cadinol, and α-trans-bergamotene; Cluster 5—mainly linalool, methyl eugenol, α-trans-bergamotene, and epi-α-cadinol; Cluster 6—mainly linalool, geraniol, and epi-α-cadinol; Cluster 7—mostly linalool and methyl chavicol; Cluster 8—mainly geranial and neral. PMID:25629084

  1. Chemical diversity in the comet population

    NASA Astrophysics Data System (ADS)

    Biver, Nicolas

    2015-08-01

    For the last 3 decades, infrared and microwave techniques have enabled the detection of up to 25 different parent molecules in the coma of comets. Several molecules have been detected in over 40 different comets. A large diversity of composition is seen in the sample, comprising comets of various dynamical origin. Abundances relative to water for the molecules can vary by a factor 3 to more than 10. The taxonomic study of a sample of comets in which the abundance of several molecules (e.g., HCN, CH3OH, CO, CH4, C2H6, H2S, H2CO, CH3CN, cs,...) has been measured does not show any clear grouping. Except for fragments of a common parent comet, every comet observed shows a different composition. The absence of any clear correlation between the volatile content of the comets and their dynamical origin (Kuiper Belt versus Oort Cloud) suggest that there is no clear dychotomy between two origins for the comets. Their diveristy in composition may also suggest that radial and temporal mixing in the early protoplanetary nebula may have played an important role.

  2. Lignocellulose-based analytical devices: bamboo as an analytical platform for chemical detection

    PubMed Central

    Kuan, Chen-Meng; York, Roger L.; Cheng, Chao-Min

    2015-01-01

    This article describes the development of lignocellulose-based analytical devices (LADs) for rapid bioanalysis in low-resource settings. LADs are constructed using either a single lignocellulose or a hybrid design consisting of multiple types of lignocellulose. LADs are simple, low-cost, easy to use, provide rapid response, and do not require external instrumentation during operation. Here, we demonstrate the implementation of LADs for food and water safety (i.e., nitrite assay in hot-pot soup, bacterial detection in water, and resazurin assay in milk) and urinalysis (i.e., nitrite, urobilinogen, and pH assays in human urine). Notably, we created a unique approach using simple chemicals to achieve sensitivity similar to that of commercially available immunochromatographic strips that is low-cost, and provides on-site, rapid detection, for instance, of Eschericia coli (E. coli) in water. PMID:26686576

  3. Automating the analytical laboratory via the Chemical Analysis Automation paradigm

    SciTech Connect

    Hollen, R.; Rzeszutko, C.

    1997-10-01

    To address the need for standardization within the analytical chemistry laboratories of the nation, the Chemical Analysis Automation (CAA) program within the US Department of Energy, Office of Science and Technology`s Robotic Technology Development Program is developing laboratory sample analysis systems that will automate the environmental chemical laboratories. The current laboratory automation paradigm consists of islands-of-automation that do not integrate into a system architecture. Thus, today the chemist must perform most aspects of environmental analysis manually using instrumentation that generally cannot communicate with other devices in the laboratory. CAA is working towards a standardized and modular approach to laboratory automation based upon the Standard Analysis Method (SAM) architecture. Each SAM system automates a complete chemical method. The building block of a SAM is known as the Standard Laboratory Module (SLM). The SLM, either hardware or software, automates a subprotocol of an analysis method and can operate as a standalone or as a unit within a SAM. The CAA concept allows the chemist to easily assemble an automated analysis system, from sample extraction through data interpretation, using standardized SLMs without the worry of hardware or software incompatibility or the necessity of generating complicated control programs. A Task Sequence Controller (TSC) software program schedules and monitors the individual tasks to be performed by each SLM configured within a SAM. The chemist interfaces with the operation of the TSC through the Human Computer Interface (HCI), a logical, icon-driven graphical user interface. The CAA paradigm has successfully been applied in automating EPA SW-846 Methods 3541/3620/8081 for the analysis of PCBs in a soil matrix utilizing commercially available equipment in tandem with SLMs constructed by CAA.

  4. Analytical DNA fingerprinting in lions: parentage, genetic diversity, and kinship.

    PubMed

    Gilbert, D A; Packer, C; Pusey, A E; Stephens, J C; O'Brien, S J

    1991-01-01

    The application of hypervariable minisatellite genomic families to the reconstruction of population genetic structure holds great promise in describing the demographic history and future prospects of free-ranging populations. This potential has not yet been realized due to unforeseen empirical constraints associated with the use of heterologous species probes, to theoretical limitations on the power of the procedure to track genic heterozygosity and kinship, and to the absence of extensive field studies to test genetic predictions. We combine here the technical development of feline-specific VNTR (variable number tandem repeat) families of genetic loci with the long-term demographic and behavioral observations of lion populations of the Serengeti ecosystem in East Africa. Minisatellite variation was used to quantify the extent of genetic variation in several populations that differed in their natural history and levels of inbreeding. Definitive parentage, both maternal and paternal, was assessed for 78 cubs born in 11 lion prides, permitting the assessment of precise genealogical relationships among some 200 lions. The extent of DNA restriction fragment sharing between lions was empirically calibrated with the coefficient of relatedness, r, in two different populations that had distinct demographic histories. The results suggest that reliable estimates of relative genetic diversity, of parentage, and of individual relatedness can be achieved in free-ranging populations, provided the minisatellite family is calibrated in established pedigrees for the species.

  5. Amazonian functional diversity from forest canopy chemical assembly.

    PubMed

    Asner, Gregory P; Martin, Roberta E; Tupayachi, Raul; Anderson, Christopher B; Sinca, Felipe; Carranza-Jiménez, Loreli; Martinez, Paola

    2014-04-15

    Patterns of tropical forest functional diversity express processes of ecological assembly at multiple geographic scales and aid in predicting ecological responses to environmental change. Tree canopy chemistry underpins forest functional diversity, but the interactive role of phylogeny and environment in determining the chemical traits of tropical trees is poorly known. Collecting and analyzing foliage in 2,420 canopy tree species across 19 forests in the western Amazon, we discovered (i) systematic, community-scale shifts in average canopy chemical traits along gradients of elevation and soil fertility; (ii) strong phylogenetic partitioning of structural and defense chemicals within communities independent of variation in environmental conditions; and (iii) strong environmental control on foliar phosphorus and calcium, the two rock-derived elements limiting CO2 uptake in tropical forests. These findings indicate that the chemical diversity of western Amazonian forests occurs in a regionally nested mosaic driven by long-term chemical trait adjustment of communities to large-scale environmental filters, particularly soils and climate, and is supported by phylogenetic divergence of traits essential to foliar survival under varying environmental conditions. Geographically nested patterns of forest canopy chemical traits will play a role in determining the response and functional rearrangement of western Amazonian ecosystems to changing land use and climate.

  6. Pretreatment and integrated analysis of spectral data reveal seaweed similarities based on chemical diversity.

    PubMed

    Wei, Feifei; Ito, Kengo; Sakata, Kenji; Date, Yasuhiro; Kikuchi, Jun

    2015-03-03

    Extracting useful information from high dimensionality and large data sets is a major challenge for data-driven approaches. The present study was aimed at developing novel integrated analytical strategies for comprehensively characterizing seaweed similarities based on chemical diversity. The chemical compositions of 107 seaweed and 2 seagrass samples were analyzed using multiple techniques, including Fourier transform infrared (FT-IR) and solid- and solution-state nuclear magnetic resonance (NMR) spectroscopy, thermogravimetry-differential thermal analysis (TG-DTA), inductively coupled plasma-optical emission spectrometry (ICP-OES), CHNS/O total elemental analysis, and isotope ratio mass spectrometry (IR-MS). The spectral data were preprocessed using non-negative matrix factorization (NMF) and NMF combined with multivariate curve resolution-alternating least-squares (MCR-ALS) methods in order to separate individual component information from the overlapping and/or broad spectral peaks. Integrated analysis of the preprocessed chemical data demonstrated distinct discrimination of differential seaweed species. Further network analysis revealed a close correlation between the heavy metal elements and characteristic components of brown algae, such as cellulose, alginic acid, and sulfated mucopolysaccharides, providing a componential basis for its metal-sorbing potential. These results suggest that this integrated analytical strategy is useful for extracting and identifying the chemical characteristics of diverse seaweeds based on large chemical data sets, particularly complicated overlapping spectral data.

  7. Physical and Chemical Analytical Analysis: A key component of Bioforensics

    SciTech Connect

    Velsko, S P

    2005-02-15

    The anthrax letters event of 2001 has raised our awareness of the potential importance of non-biological measurements on samples of biological agents used in a terrorism incident. Such measurements include a variety of mass spectral, spectroscopic, and other instrumental techniques that are part of the current armamentarium of the modern materials analysis or analytical chemistry laboratory. They can provide morphological, trace element, isotopic, and other molecular ''fingerprints'' of the agent that may be key pieces of evidence, supplementing that obtained from genetic analysis or other biological properties. The generation and interpretation of such data represents a new domain of forensic science, closely aligned with other areas of ''microbial forensics''. This paper describes some major elements of the R&D agenda that will define this sub-field in the immediate future and provide the foundations for a coherent national capability. Data from chemical and physical analysis of BW materials can be useful to an investigation of a bio-terror event in two ways. First, it can be used to compare evidence samples collected at different locations where such incidents have occurred (e.g. between the powders in the New York and Washington letters in the Amerithrax investigation) or between the attack samples and those seized during the investigation of sites where it is suspected the material was manufactured (if such samples exist). Matching of sample properties can help establish the relatedness of disparate incidents, and mis-matches might exclude certain scenarios, or signify a more complex etiology of the events under investigation. Chemical and morphological analysis for sample matching has a long history in forensics, and is likely to be acceptable in principle in court, assuming that match criteria are well defined and derived from known limits of precision of the measurement techniques in question. Thus, apart from certain operational issues (such as how to

  8. Origin of Chemical Diversity in Prochloron-Tunicate Symbiosis

    PubMed Central

    Lin, Zhenjian; Torres, Joshua P.; Tianero, M. Diarey; Kwan, Jason C.

    2016-01-01

    ABSTRACT Diversity-generating metabolism leads to the evolution of many different chemicals in living organisms. Here, by examining a marine symbiosis, we provide a precise evolutionary model of how nature generates a family of novel chemicals, the cyanobactins. We show that tunicates and their symbiotic Prochloron cyanobacteria share congruent phylogenies, indicating that Prochloron phylogeny is related to host phylogeny and not to external habitat or geography. We observe that Prochloron exchanges discrete functional genetic modules for cyanobactin secondary metabolite biosynthesis in an otherwise conserved genetic background. The module exchange leads to gain or loss of discrete chemical functional groups. Because the underlying enzymes exhibit broad substrate tolerance, discrete exchange of substrates and enzymes between Prochloron strains leads to the rapid generation of chemical novelty. These results have implications in choosing biochemical pathways and enzymes for engineered or combinatorial biosynthesis. IMPORTANCE While most biosynthetic pathways lead to one or a few products, a subset of pathways are diversity generating and are capable of producing thousands to millions of derivatives. This property is highly useful in biotechnology since it enables biochemical or synthetic biological methods to create desired chemicals. A fundamental question has been how nature itself creates this chemical diversity. Here, by examining the symbiosis between coral reef animals and bacteria, we describe the genetic basis of chemical variation with unprecedented precision. New compounds from the cyanobactin family are created by either varying the substrate or importing needed enzymatic functions from other organisms or via both mechanisms. This natural process matches successful laboratory strategies to engineer the biosynthesis of new chemicals and teaches a new strategy to direct biosynthesis. PMID:27037119

  9. Opportunities for synthetic biology in antibiotics: expanding glycopeptide chemical diversity.

    PubMed

    Thaker, Maulik N; Wright, Gerard D

    2015-03-20

    Synthetic biology offers a new path for the exploitation and improvement of natural products to address the growing crisis in antibiotic resistance. All antibiotics in clinical use are facing eventual obsolesce as a result of the evolution and dissemination of resistance mechanisms, yet there are few new drug leads forthcoming from the pharmaceutical sector. Natural products of microbial origin have proven over the past 70 years to be the wellspring of antimicrobial drugs. Harnessing synthetic biology thinking and strategies can provide new molecules and expand chemical diversity of known antibiotic scaffolds to provide much needed new drug leads. The glycopeptide antibiotics offer paradigmatic scaffolds suitable for such an approach. We review these strategies here using the glycopeptides as an example and demonstrate how synthetic biology can expand antibiotic chemical diversity to help address the growing resistance crisis.

  10. Chemically diverse and multifunctional hybrid organic-inorganic perovskites

    NASA Astrophysics Data System (ADS)

    Li, Wei; Wang, Zheming; Deschler, Felix; Gao, Song; Friend, Richard H.; Cheetham, Anthony K.

    2017-02-01

    Hybrid organic-inorganic perovskites (HOIPs) can have a diverse range of compositions including halides, azides, formates, dicyanamides, cyanides and dicyanometallates. These materials have several common features, including their classical ABX3 perovskite architecture and the presence of organic amine cations that occupy the A-sites. Current research in HOIPs tends to focus on metal halide HOIPs, which show promise for use in solar cells and optoelectronic devices; however, the other subclasses also exhibit a diverse range of physical properties. In this Review, we summarize the chemical variability and structural diversity of all known HOIP subclasses. We also present a comprehensive account of their intriguing physical properties, including photovoltaic and optoelectronic properties, dielectricity, magnetism, ferroelectricity, ferroelasticity and multiferroicity. Moreover, we discuss the current challenges and future opportunities in this exciting field.

  11. "Diversomers": an approach to nonpeptide, nonoligomeric chemical diversity.

    PubMed Central

    DeWitt, S H; Kiely, J S; Stankovic, C J; Schroeder, M C; Cody, D M; Pavia, M R

    1993-01-01

    Solid-phase chemistry, organic synthesis, and an apparatus for multiple, simultaneous synthesis have been combined to generate libraries of organic compounds ("diversomers"). Arrays of compounds were synthesized over two to three steps incorporating chemically diverse building blocks on a polystyrene-based solid support in a multiple, simultaneous manner. The generality of this approach is illustrated by the syntheses of dipeptides, hydantoins, and benzodiazepines. PMID:8394002

  12. Safety in the Chemical Laboratory. Safety in the Analytical Laboratory.

    ERIC Educational Resources Information Center

    Ewing, Galen W.

    1990-01-01

    Safety issues specifically related to the analytical laboratory are discussed including hazardous reagents, transferring samples, cleaning apparatus, eye protection, and equipment damage. Special attention is given to techniques which not only endanger the technician but also endanger expensive equipment. (CW)

  13. CTEPP NC DATA ANALYTICAL RESULTS ORGANIZED BY CHEMICAL AND MEDIA

    EPA Science Inventory

    This data set contains the field sample data by chemical and matrix. The data are organized at the sample, chemical level.

    The Children’s Total Exposure to Persistent Pesticides and Other Persistent Pollutant (CTEPP) study was one of the largest aggregate exposure studies of y...

  14. Covering chemical diversity of genetically-modified tomatoes using metabolomics for objective substantial equivalence assessment.

    PubMed

    Kusano, Miyako; Redestig, Henning; Hirai, Tadayoshi; Oikawa, Akira; Matsuda, Fumio; Fukushima, Atsushi; Arita, Masanori; Watanabe, Shin; Yano, Megumu; Hiwasa-Tanase, Kyoko; Ezura, Hiroshi; Saito, Kazuki

    2011-02-16

    As metabolomics can provide a biochemical snapshot of an organism's phenotype it is a promising approach for charting the unintended effects of genetic modification. A critical obstacle for this application is the inherently limited metabolomic coverage of any single analytical platform. We propose using multiple analytical platforms for the direct acquisition of an interpretable data set of estimable chemical diversity. As an example, we report an application of our multi-platform approach that assesses the substantial equivalence of tomatoes over-expressing the taste-modifying protein miraculin. In combination, the chosen platforms detected compounds that represent 86% of the estimated chemical diversity of the metabolites listed in the LycoCyc database. Following a proof-of-safety approach, we show that % had an acceptable range of variation while simultaneously indicating a reproducible transformation-related metabolic signature. We conclude that multi-platform metabolomics is an approach that is both sensitive and robust and that it constitutes a good starting point for characterizing genetically modified organisms.

  15. Covering Chemical Diversity of Genetically-Modified Tomatoes Using Metabolomics for Objective Substantial Equivalence Assessment

    PubMed Central

    Hirai, Tadayoshi; Oikawa, Akira; Matsuda, Fumio; Fukushima, Atsushi; Arita, Masanori; Watanabe, Shin; Yano, Megumu; Hiwasa-Tanase, Kyoko; Ezura, Hiroshi; Saito, Kazuki

    2011-01-01

    As metabolomics can provide a biochemical snapshot of an organism's phenotype it is a promising approach for charting the unintended effects of genetic modification. A critical obstacle for this application is the inherently limited metabolomic coverage of any single analytical platform. We propose using multiple analytical platforms for the direct acquisition of an interpretable data set of estimable chemical diversity. As an example, we report an application of our multi-platform approach that assesses the substantial equivalence of tomatoes over-expressing the taste-modifying protein miraculin. In combination, the chosen platforms detected compounds that represent 86% of the estimated chemical diversity of the metabolites listed in the LycoCyc database. Following a proof-of-safety approach, we show that % had an acceptable range of variation while simultaneously indicating a reproducible transformation-related metabolic signature. We conclude that multi-platform metabolomics is an approach that is both sensitive and robust and that it constitutes a good starting point for characterizing genetically modified organisms. PMID:21359231

  16. Effect-Based Screening Methods for Water Quality Characterization Will Augment Conventional Analyte-by-Analyte Chemical Methods in Research As Well As Regulatory Monitoring

    EPA Science Inventory

    Conventional approaches to water quality characterization can provide data on individual chemical components of each water sample. This analyte-by-analyte approach currently serves many useful research and compliance monitoring needs. However these approaches, which require a ...

  17. Analytical verification of waterborne chemical treatment regimens in hatchery raceways

    USGS Publications Warehouse

    Rach, J.J.; Ramsay, R.T.

    2000-01-01

    Chemical therapy for control and prevention of fish diseases is a necessary and common practice in aquaculture. Many factors affect the accuracy of a chemical treatment application, such as the functioning of the chemical delivery system, calculation of chemical quantities to be delivered, water temperature, geometry of the culture unit, inlet-outlet structure, the influence of aerators, wind movement, and measurement of water volumes and flow rates. Three separate trials were conducted at the Osceola Fish Hatchery, a facility of the Wisconsin Department of Natural Resources, evaluating the accuracy of flow-through hydrogen peroxide treatments applied to 1, 3, or 9 raceways that were connected in series. Raceways were treated with 50 or 75 ??L/L of hydrogen peroxide for 30 min. Chemical concentrations were determined titrimetrically. The target treatment regimen was not realized in any of the applications. Chemical concentrations dropped and exposure times increased with each additional raceway treated in series. Single introduction of a therapeutant to more than three raceways in series is not recommended. Factors that interfered with the accuracy of the treatments were culture unit configuration, aeration, and flow rates. Several treatment modifications were identified that would result in more accurate chemical treatments.

  18. Propolis volatile compounds: chemical diversity and biological activity: a review

    PubMed Central

    2014-01-01

    Propolis is a sticky material collected by bees from plants, and used in the hive as building material and defensive substance. It has been popular as a remedy in Europe since ancient times. Nowadays, propolis use in over-the-counter preparations, “bio”-cosmetics and functional foods, etc., increases. Volatile compounds are found in low concentrations in propolis, but their aroma and significant biological activity make them important for propolis characterisation. Propolis is a plant-derived product: its chemical composition depends on the local flora at the site of collection, thus it offers a significant chemical diversity. The role of propolis volatiles in identification of its plant origin is discussed. The available data about chemical composition of propolis volatiles from different geographic regions are reviewed, demonstrating significant chemical variability. The contribution of volatiles and their constituents to the biological activities of propolis is considered. Future perspectives in research on propolis volatiles are outlined, especially in studying activities other than antimicrobial. PMID:24812573

  19. Single-Molecule Electronics: Chemical and Analytical Perspectives

    NASA Astrophysics Data System (ADS)

    Nichols, Richard J.; Higgins, Simon J.

    2015-07-01

    It is now possible to measure the electrical properties of single molecules using a variety of techniques including scanning probe microcopies and mechanically controlled break junctions. Such measurements can be made across a wide range of environments including ambient conditions, organic liquids, ionic liquids, aqueous solutions, electrolytes, and ultra high vacuum. This has given new insights into charge transport across molecule electrical junctions, and these experimental methods have been complemented with increasingly sophisticated theory. This article reviews progress in single-molecule electronics from a chemical perspective and discusses topics such as the molecule-surface coupling in electrical junctions, chemical control, and supramolecular interactions in junctions and gating charge transport. The article concludes with an outlook regarding chemical analysis based on single-molecule conductance.

  20. Single-Molecule Electronics: Chemical and Analytical Perspectives.

    PubMed

    Nichols, Richard J; Higgins, Simon J

    2015-01-01

    It is now possible to measure the electrical properties of single molecules using a variety of techniques including scanning probe microcopies and mechanically controlled break junctions. Such measurements can be made across a wide range of environments including ambient conditions, organic liquids, ionic liquids, aqueous solutions, electrolytes, and ultra high vacuum. This has given new insights into charge transport across molecule electrical junctions, and these experimental methods have been complemented with increasingly sophisticated theory. This article reviews progress in single-molecule electronics from a chemical perspective and discusses topics such as the molecule-surface coupling in electrical junctions, chemical control, and supramolecular interactions in junctions and gating charge transport. The article concludes with an outlook regarding chemical analysis based on single-molecule conductance.

  1. A Decision Analytic Approach to Exposure-Based Chemical Prioritization

    EPA Science Inventory

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient d...

  2. 40 CFR 141.24 - Organic chemicals, sampling and analytical requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Organic chemicals, sampling and... Requirements § 141.24 Organic chemicals, sampling and analytical requirements. (a)-(d) (e) Analyses for the... and 515.1 are in Methods for the Determination of Organic Compounds in Drinking Water,...

  3. 40 CFR 141.24 - Organic chemicals, sampling and analytical requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Organic chemicals, sampling and... Requirements § 141.24 Organic chemicals, sampling and analytical requirements. (a)-(d) (e) Analyses for the... and 515.1 are in Methods for the Determination of Organic Compounds in Drinking Water,...

  4. 40 CFR 141.24 - Organic chemicals, sampling and analytical requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Organic chemicals, sampling and... Requirements § 141.24 Organic chemicals, sampling and analytical requirements. (a)-(d) (e) Analyses for the... and 515.1 are in Methods for the Determination of Organic Compounds in Drinking Water,...

  5. 40 CFR 141.24 - Organic chemicals, sampling and analytical requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Organic chemicals, sampling and... Requirements § 141.24 Organic chemicals, sampling and analytical requirements. (a)-(d) (e) Analyses for the... and 515.1 are in Methods for the Determination of Organic Compounds in Drinking Water,...

  6. Menagerie of Viruses: Diverse Chemical Sequences or Simple Electrostatics?

    NASA Astrophysics Data System (ADS)

    Muthukumar, M.

    2008-03-01

    The genome packing in hundreds of viruses is investigated by analyzing the chemical sequences of the genomes and the corresponding capsid proteins, in combination with experimental facts on the structures of the packaged genomes. Based on statistical mechanics arguments and computer simulations, we have derived a universal model, based simply on non-specific electrostatic interactions. Our model is able to predict the essential aspects of genome packing in diversely different viruses, such as the genome size and its density distribution. Our result is in contrast to the long-held view that specific interactions between the sequenced amino acid residues and the nucleotides of the genome control the genome packing. Implications of this finding in the evolution and biotechnology will be discussed.

  7. Chemically diverse, episodic volcanism offshore southern and peninsular California

    SciTech Connect

    Davis, A.S.; Gunn, S.H. ); Bohrson, W.A. . Dept. Earth and Space Sciences)

    1993-04-01

    Volcanic rocks recovered from eight seamounts offshore southern and peninsular California are chemically diverse. Compositions of lavas from seven small to moderately sized seamounts between 30.5[degree] and 34.0 N latitudes include low-K[sub 2]O tholeiitic, transitional, and mildly to moderately alkalic basalt. Volcanic rocks from the upper part of the much larger and morphologically complex edifice of Rocas Alijos, offshore central Baja California at about 25.0 N latitude, are highly differentiated trachyandesite and trachyte. The low-K[sub 2]O basalts are MORB-like with low abundances of incompatible elements and lower [sup 87]Sr/[sup 86]Sr and higher [sup 143]Nd/[sup 144]Nd ratios than MORB from the East Pacific Rise. The alkalic compositions have higher abundances of incompatible elements and isotopic data indicate more variably enriched mantle sources than those of seamounts near the East Pacific Rise, but the compositions of all samples are within the mantle array defined by other ocean-island basalts. [sup 40]Ar/[sup 39]Ar laser fusion ages for the seamounts span a large range. MORB-like lava from one of the northern edifices is as old as the underlying oceanic crust ([approximately]23 Ma), indicating that it originated at a spreading center. Other seamount lava ages are much younger (16.6--9.1 Ma) than the underlying oceanic crust. The trachytes from Rocas Alijos are less than 300,000 years old, indicating that the last volcanism on this large edifice occurred recently. The region offshore southern and peninsular California is tectonically complex and has many volcanic edifices of varying sizes, shapes, and orientations. The data available for volcanic rocks from this region suggest that the seamounts formed from multiple episodes of chemically diverse volcanism occurring sporadically from early Miocene to Recent.

  8. State-of-the-Art of (Bio)Chemical Sensor Developments in Analytical Spanish Groups

    PubMed Central

    Plata, María Reyes; Contento, Ana María; Ríos, Angel

    2010-01-01

    (Bio)chemical sensors are one of the most exciting fields in analytical chemistry today. The development of these analytical devices simplifies and miniaturizes the whole analytical process. Although the initial expectation of the massive incorporation of sensors in routine analytical work has been truncated to some extent, in many other cases analytical methods based on sensor technology have solved important analytical problems. Many research groups are working in this field world-wide, reporting interesting results so far. Modestly, Spanish researchers have contributed to these recent developments. In this review, we summarize the more representative achievements carried out for these groups. They cover a wide variety of sensors, including optical, electrochemical, piezoelectric or electro-mechanical devices, used for laboratory or field analyses. The capabilities to be used in different applied areas are also critically discussed. PMID:22319260

  9. State-of-the-art of (bio)chemical sensor developments in analytical Spanish groups.

    PubMed

    Plata, María Reyes; Contento, Ana María; Ríos, Angel

    2010-01-01

    (Bio)chemical sensors are one of the most exciting fields in analytical chemistry today. The development of these analytical devices simplifies and miniaturizes the whole analytical process. Although the initial expectation of the massive incorporation of sensors in routine analytical work has been truncated to some extent, in many other cases analytical methods based on sensor technology have solved important analytical problems. Many research groups are working in this field world-wide, reporting interesting results so far. Modestly, Spanish researchers have contributed to these recent developments. In this review, we summarize the more representative achievements carried out for these groups. They cover a wide variety of sensors, including optical, electrochemical, piezoelectric or electro-mechanical devices, used for laboratory or field analyses. The capabilities to be used in different applied areas are also critically discussed.

  10. Interfacial characterization and analytical applications of chemically-modified surfaces

    SciTech Connect

    Wang, Jianhong

    1998-02-23

    The goal of this work is to explore several new strategies and approaches to the surface modification and the microscopic characterization of interfaces in the areas mainly targeting sensor technologies that are of interest to environmental control or monitoring, and scanning probe microscopies techniques that can monitor interfacial chemical reactions in real time. Centered on the main theme, four specific topics are presented as four chapters in this dissertation following the general introduction. Chapter 1 describes the development of two immobilization schemes for covalently immobilizing fluoresceinamine at cellulose acetate and its application as a pH sensing film. Chapter 2 investigates the applicability of SFM to following the base-hydrolysis of a dithio-bis(succinimidylundecanoate) monolayer at gold in situ. Chapter 3 studies the mechanism for the accelerated rate of hydrolysis of the dithio-bis(succinimidylundecanoate) monolayer at Au(111) surface. Chapter 4 focuses on the development of an electrochemical approach to the elimination of chloride interference in Chemical Oxygen Demand (COD) analysis of waste water. The procedures, results and conclusions are described in each chapter. This report contains the introduction, references, and general conclusions. Chapters have been processed separately for inclusion on the data base. 95 refs.

  11. Statistical Data Analyses of Trace Chemical, Biochemical, and Physical Analytical Signatures

    SciTech Connect

    Udey, Ruth Norma

    2013-01-01

    Analytical and bioanalytical chemistry measurement results are most meaningful when interpreted using rigorous statistical treatments of the data. The same data set may provide many dimensions of information depending on the questions asked through the applied statistical methods. Three principal projects illustrated the wealth of information gained through the application of statistical data analyses to diverse problems.

  12. Analytical methods for a national study of chemical residues in fish. 2. Pesticides and polychlorinated biphenyls

    SciTech Connect

    Marquis, P.J.; Hanson, R.L.; Larsen, M.L.; DeVita, W.M.; Butterworth, B.C.

    1994-01-01

    Analytical methods and a quality assurance plan have been developed to determine the concentration of a select group of bioaccumulatable chemicals in fish tissue. The analytes include Polychlorinated biphenyls (PCBs) and 21 pesticides and industrial chemicals. The methodology has been used to conduct a survey of chemical contaminants in fish from nearly 400 major watersheds in the United States. The methodology consists of the preparation of a single extract via soxhlet extraction, gel permeation and silica gel chromatography and quantification by HRGC/LRMS. The minimum level of detection for most analytes is near 1 ng/g. Rigorous quality assurance/quality control criteria have been developed to assure the generation of high quality data.

  13. The delayed contribution of low and intermediate mass stars to chemical galactic enrichment: An analytical approach

    NASA Astrophysics Data System (ADS)

    Franco, I.; Carigi, L.

    2008-10-01

    We find a new analytical solution for the chemical evolution equations, taking into account the delayed contribution of all low and intermediate mass stars (LIMS) as one representative star that enriches the interstellar medium. This solution is built only for star formation rate proportional to the gas mass in a closed box model. We obtain increasing C/O and N/O ratios with increasing O/H, behavior impossible to match with the Instantaneous Recycling Approximation (IRA). Our results, obtained by two analytical equations, are very similar to those found by numerical models that consider the lifetimes of each star. This delayed model reproduces successfully the evolution of the C/O-O/H and Y - O relations in the solar vicinity. This analytical approximation is a useful tool to study the chemical evolution of elements produced by LIMS when a galactic chemical evolutionary code is not available.

  14. A results-based process for evaluation of diverse visual analytics tools

    NASA Astrophysics Data System (ADS)

    Rubin, Gary; Berger, David H.

    2013-05-01

    With the pervasiveness of still and full-motion imagery in commercial and military applications, the need to ingest and analyze these media has grown rapidly in recent years. Additionally, video hosting and live camera websites provide a near real-time view of our changing world with unprecedented spatial coverage. To take advantage of these controlled and crowd-sourced opportunities, sophisticated visual analytics (VA) tools are required to accurately and efficiently convert raw imagery into usable information. Whether investing in VA products or evaluating algorithms for potential development, it is important for stakeholders to understand the capabilities and limitations of visual analytics tools. Visual analytics algorithms are being applied to problems related to Intelligence, Surveillance, and Reconnaissance (ISR), facility security, and public safety monitoring, to name a few. The diversity of requirements means that a onesize- fits-all approach to performance assessment will not work. We present a process for evaluating the efficacy of algorithms in real-world conditions, thereby allowing users and developers of video analytics software to understand software capabilities and identify potential shortcomings. The results-based approach described in this paper uses an analysis of end-user requirements and Concept of Operations (CONOPS) to define Measures of Effectiveness (MOEs), test data requirements, and evaluation strategies. We define metrics that individually do not fully characterize a system, but when used together, are a powerful way to reveal both strengths and weaknesses. We provide examples of data products, such as heatmaps, performance maps, detection timelines, and rank-based probability-of-detection curves.

  15. The impact of plant chemical diversity on plant-herbivore interactions at the community level.

    PubMed

    Salazar, Diego; Jaramillo, Alejandra; Marquis, Robert J

    2016-08-01

    Understanding the role of diversity in ecosystem processes and species interactions is a central goal of ecology. For plant-herbivore interactions, it has been hypothesized that when plant species diversity is reduced, loss of plant biomass to herbivores increases. Although long-standing, this hypothesis has received mixed support. Increasing plant chemical diversity with increasing plant taxonomic diversity is likely to be important for plant-herbivore interactions at the community level, but the role of chemical diversity is unexplored. Here we assess the effect of volatile chemical diversity on patterns of herbivore damage in naturally occurring patches of Piper (Piperaceae) shrubs in a Costa Rican lowland wet forest. Volatile chemical diversity negatively affected total, specialist, and generalist herbivore damage. Furthermore, there were differences between the effects of high-volatility and low-volatility chemical diversity on herbivore damage. High-volatility diversity reduced specialist herbivory, while low-volatility diversity reduced generalist herbivory. Our data suggest that, although increased plant diversity is expected to reduce average herbivore damage, this pattern is likely mediated by the diversity of defensive compounds and general classes of anti-herbivore traits, as well as the degree of specialization of the herbivores attacking those plants.

  16. Calcification of coccolithophores in diverse chemical oceanic settings

    NASA Astrophysics Data System (ADS)

    Beaufort, L.; Ruiz-Pino, D.; Metzl, N.; Goyet, C.

    2008-12-01

    The constant release of carbon in the atmosphere from human activity induces ocean acidification, with potential threat for calcifying organisms such as coccolithophores. The effect of acidification on Coccolithophores is not yet clearly understood: Culture experiments appears to show complex results and may induce opposite conclusions on the calcification response of the algae to an increase of pCO2 at the species level (for E. huxleyi compare Riebesell (2000) and Iglesias-Rodriguez et al. (2008)) or depending of the species (Langer et al., 2006). Natural oceanic environment offers an excellent laboratory to test the response of coccolithophores to various chemical settings. It is for example possible to sample a large spectrum of alkalinity or of carbonate saturation state conditions in the present surface ocean. Here we present estimation of the degree of calcification of important coccolithophore taxa in 170 water samples collected in diverse oceanic settings (Patagonian Shelf, Southern Indian Ocean, and Tropical Pacific Ocean). In this water collection, temperature, alkalinity, and pH ranged from 3 to 31° C, 2108 to 2418 μmole kg-1 and 7.6 to 8.2 respectively. The calcite weight of the coccoliths and of the coccospheres of Gephyrocapsa sp and of Emiliania huxleyi was estimated using automated pattern recognition and automated morphometry software. The results indicate that the degree of calcification of these species strongly depends on alkalinity, temperature and calcite saturation state. In area of high alkalinity, high temperature, and high calcite saturation state, these coccolithophores secrete the heaviest coccospheres and coccoliths. The facts that in the Chilean upwelling, where pH was the lowest, the mean coccolith weights are in the average of the global distribution and that the mean lightest and mean heaviest coccoliths are found both at higher pH, indicate that the effect of pH on its studied range is not a critical parameter that can be studied

  17. [Analytical evaluation of significant chemical and physico-chemical parameters in water for human consumption].

    PubMed

    Ferrara, L; Forgione, P; Imperatrice, M L; Liguori, M; Menna, A; Schettino, O

    1993-03-01

    A quality control of drinking water has been performed in hospitals and schools located in the Vomero-Area of Naples. Some chemical pollutants (iron, manganese, ammonia nitrogen, nitrite, nitrate, fluoride) as well as chemical and physical parameters (hardness, pH, electric conductivity, chloride, cations) have been periodically analyzed from Autumn 1991 to Summer 1992.

  18. 75 years of the Division of Analytical Chemistry of the American Chemical Society.

    PubMed

    Hirsch, Roland F

    2013-04-02

    The Division of Analytical Chemistry is celebrating the 75th anniversary of its founding in 1938. We celebrate the continuing high importance of our discipline for all aspects of chemical science and for its applications in so many aspects of everyday life. We especially celebrate the accomplishments of our fellow analytical chemists through the years, and the impact we have had on the profession. This article is a short history of the Division within the context of the parallel development of our profession and our science.

  19. Chemical and Analytical Sciences Division progress report for the period January 1, 1993--December 31, 1994

    SciTech Connect

    Poutsma, M.L.

    1995-06-01

    This report provides brief summaries of progress in the Chemical and Analytical Sciences Division (CASD) during 1993 and 1994. The first four chapters, which cover the research mission, are organized to mirror the major organizational units of the division and indicate the scope of the research portfolio. These divisions are the Analytical Spectroscopy Section, Nuclear and Radiochemistry Section, Organic Chemistry Section, and Physical and Materials Chemistry Section. The fifth and sixth chapters summarize the support activities within CASD that are critical for research progress. Finally, the appendices indicate the productivity and recognition of the staff in terms of various forms of external publications, professional activities, and awards.

  20. Chemical multi-contamination drives benthic prokaryotic diversity in the anthropized Toulon Bay.

    PubMed

    Misson, Benjamin; Garnier, Cédric; Lauga, Béatrice; Dang, Duc Huy; Ghiglione, Jean-François; Mullot, Jean-Ulrich; Duran, Robert; Pringault, Olivier

    2016-06-15

    Investigating the impact of human activities on marine coastal ecosystems remains difficult because of the co-occurrence of numerous natural and human-induced gradients. Our aims were (i) to evaluate the links between the chemical environment as a whole and microbial diversity in the benthic compartment, and (ii) to compare the contributions of anthropogenic and natural chemical gradients to microbial diversity shifts. We studied surface sediments from 54 sampling sites in the semi-enclosed Toulon Bay (NW Mediterranean) exposed to high anthropogenic pressure. Previously published chemical data were completed by new measurements, resulting in an in depth geochemical characterization by 29 representative environmental variables. Bacterial and archaeal diversity was assessed by terminal restriction fragment length polymorphism profiling on a selection of samples distributed along chemical gradients. Multivariate statistical analyses explained from 45% to 80% of the spatial variation in microbial diversity, considering only the chemical variables. A selection of trace metals of anthropogenic origin appeared to be strong structural factors for both bacterial and archaeal communities. Bacterial terminal restriction fragment (T-RF) richness correlated strongly with both anthropogenic and natural chemical gradients, whereas archaeal T-RF richness demonstrated fewer links with chemical variables. No significant decrease in diversity was evidenced in relation to chemical contamination, suggesting a high adaptive potential of benthic microbial communities in Toulon Bay.

  1. Do multiple herbivores maintain chemical diversity of Scots pine monoterpenes?

    PubMed

    Iason, Glenn R; O'Reilly-Wapstra, Julianne M; Brewer, Mark J; Summers, Ron W; Moore, Ben D

    2011-05-12

    A central issue in our understanding of the evolution of the diversity of plant secondary metabolites (PSMs) is whether or not compounds are functional, conferring an advantage to the plant, or non-functional. We examine the hypothesis that the diversity of monoterpene PSMs within a plant species (Scots pine Pinus sylvestris) may be explained by different compounds acting as defences against high-impact herbivores operating at different life stages. We also hypothesize that pairwise coevolution, with uncorrelated interactions, is more likely to result in greater PSM diversity, than diffuse coevolution. We tested whether up to 13 different monoterpenes in Scots pine were inhibitory to herbivory by slugs (Arion ater), bank voles (Clethrionomys glareolus), red deer (Cervus elaphus) and capercaillie (Tetrao urogallus), each of which attack trees at a different life stage. Plants containing more α-pinene were avoided by both slugs and capercaillie, which may act as reinforcing selective agents for this dominant defensive compound. Herbivory by red deer and capercaillie were, respectively, weakly negatively associated with δ(3)-carene, and strongly negatively correlated with the minor compound β-ocimene. Three of the four herbivores are probably contributory selective agents on some of the terpenes, and thus maintain some, but by no means all, of the phytochemical diversity in the species. The correlated defensive function of α-pinene against slugs and capercaillie is consistent with diffuse coevolutionary processes.

  2. AIScore chemically diverse empirical scoring function employing quantum chemical binding energies of hydrogen-bonded complexes.

    PubMed

    Raub, Stephan; Steffen, Andreas; Kämper, Andreas; Marian, Christel M

    2008-07-01

    In this work we report on a novel scoring function that is based on the LUDI model and focuses on the prediction of binding affinities. AIScore extends the original FlexX scoring function using a chemically diverse set of hydrogen-bonded interactions derived from extensive quantum chemical ab initio calculations. Furthermore, we introduce an algorithmic extension for the treatment of multifurcated hydrogen bonds (XFurcate). Charged and resonance-assisted hydrogen bond energies and hydrophobic interactions as well as a scaling factor for implicit solvation were fitted to experimental data. To this end, we assembled a set of 101 protein-ligand complexes with known experimental binding affinities. Tightly bound water molecules in the active site were considered to be an integral part of the binding pocket. Compared to the original FlexX scoring function, AIScore significantly improves the prediction of the binding free energies of the complexes in their native crystal structures. In combination with XFurcate, AIScore yields a Pearson correlation coefficient of R P = 0.87 on the training set. In a validation run on the PDBbind test set we achieved an R P value of 0.46 for 799 attractively scored complexes, compared to a value of R P = 0.17 and 739 bound complexes obtained with the FlexX original scoring function. The redocking capability of AIScore, on the other hand, does not fully reach the good performance of the original FlexX scoring function. This finding suggests that AIScore should rather be used for postscoring in combination with the standard FlexX incremental ligand construction scheme.

  3. Prioritization of chemicals in the aquatic environment based on risk assessment: analytical, modeling and regulatory perspective.

    PubMed

    Guillén, D; Ginebreda, A; Farré, M; Darbra, R M; Petrovic, M; Gros, M; Barceló, D

    2012-12-01

    The extensive and intensive use of chemicals in our developed, highly technological society includes more than 100,000 chemical substances. Significant scientific evidence has lead to the recognition that their improper use and release may result in undesirable and harmful side-effects on both the human and ecosystem health. To cope with them, appropriate risk assessment processes and related prioritization schemes have been developed in order to provide the necessary scientific support for regulatory procedures. In the present paper, two of the elements that constitute the core of risk assessment, namely occurrence and hazard effects, have been discussed. Recent advances in analytical chemistry (sample pre-treatment and instrumental equipment, etc.) have allowed for more comprehensive monitoring of environmental pollution reaching limits of detection up to sub ng L(-1). Alternative to analytical measurements, occurrence models can provide risk managers with a very interesting approach for estimating environmental concentrations from real or hypothetical scenarios. The most representative prioritization schemes used for issuing lists of concerning chemicals have also been examined and put in the context of existing environmental policies for protection strategies and regulations. Finally, new challenges in the field of risk-assessment have been outlined, including those posed by new materials (i.e., nanomaterials), transformation products, multi-chemical exposure, or extension of the risk assessment process to the whole ecosystem.

  4. Chemical Diversity in Lippia alba (Mill.) N. E. Brown Germplasm

    PubMed Central

    Camêlo, Lídia Cristina Alves; Pinheiro, José Baldin; Andrade, Thiago Matos; Alves, Péricles Barreto

    2015-01-01

    The aim of this study was to perform chemical characterization of Lippia alba accessions from the Active Germplasm Bank of the Federal University of Sergipe. A randomized block experimental design with two replications was applied. The analysis of the chemical composition of the essential oils was conducted using a gas chromatograph coupled to a mass spectrometer. The chemical composition of the essential oils allowed the accessions to be allocated to the following six groups: group 1: linalool, 1,8-cineole, and caryophyllene oxide; group 2: linalool, geranial, neral, 1,8-cineol, and caryophyllene oxide; group 3: limonene, carvone, and sabinene; group 4: carvone, limonene, g-muurolene, and myrcene; group 5: neral, geranial, and caryophyllene oxide; and group 6: geranial, neral, o-cymene, limonene, and caryophyllene oxide. PMID:26075292

  5. Chemical Diversity in Lippia alba (Mill.) N. E. Brown Germplasm.

    PubMed

    Blank, Arie Fitzgerald; Camêlo, Lídia Cristina Alves; Arrigoni-Blank, Maria de Fátima; Pinheiro, José Baldin; Andrade, Thiago Matos; Niculau, Edenilson dos Santos; Alves, Péricles Barreto

    2015-01-01

    The aim of this study was to perform chemical characterization of Lippia alba accessions from the Active Germplasm Bank of the Federal University of Sergipe. A randomized block experimental design with two replications was applied. The analysis of the chemical composition of the essential oils was conducted using a gas chromatograph coupled to a mass spectrometer. The chemical composition of the essential oils allowed the accessions to be allocated to the following six groups: group 1: linalool, 1,8-cineole, and caryophyllene oxide; group 2: linalool, geranial, neral, 1,8-cineol, and caryophyllene oxide; group 3: limonene, carvone, and sabinene; group 4: carvone, limonene, g-muurolene, and myrcene; group 5: neral, geranial, and caryophyllene oxide; and group 6: geranial, neral, o-cymene, limonene, and caryophyllene oxide.

  6. Demonstrating Chemical and Analytical Concepts in the Undergraduate Laboratory Using Capillary Electrophoresis and Micellar Electrokinetic Chromatography

    NASA Astrophysics Data System (ADS)

    Palmer, Christopher P.

    1999-11-01

    This paper describes instrumental analysis laboratory exercises that utilize capillary electrophoresis and micellar electrokinetic chromatography to demonstrate several analytical and chemical principles. Alkyl parabens (4-hydroxy alkyl benzoates), which are common ingredients in cosmetic formulations, are separated by capillary electrophoresis. The electrophoretic mobilities of the parabens can be explained on the basis of their relative size. 3-Hydroxy ethylbenzoate is also separated to demonstrate the effect of substituent position on the acid dissociation constant and the effect this has on electrophoretic mobility. Homologous series of alkyl benzoates and alkyl phthalates (common plasticizers) are separated by micellar electrokinetic chromatography at four surfactant concentrations. This exercise demonstrates the separation mechanism of micellar electrokinetic chromatography, the concept of chromatographic phase ratio, and the concepts of micelle formation. A photodiode array detector is used in both exercises to demonstrate the advantages and limitations of the detector and to demonstrate the effect of pH and substituent position on the spectra of the analytes.

  7. An Analytical Investigation of Three General Methods of Calculating Chemical-Equilibrium Compositions

    NASA Technical Reports Server (NTRS)

    Zeleznik, Frank J.; Gordon, Sanford

    1960-01-01

    The Brinkley, Huff, and White methods for chemical-equilibrium calculations were modified and extended in order to permit an analytical comparison. The extended forms of these methods permit condensed species as reaction products, include temperature as a variable in the iteration, and permit arbitrary estimates for the variables. It is analytically shown that the three extended methods can be placed in a form that is independent of components. In this form the Brinkley iteration is identical computationally to the White method, while the modified Huff method differs only'slightly from these two. The convergence rates of the modified Brinkley and White methods are identical; and, further, all three methods are guaranteed to converge and will ultimately converge quadratically. It is concluded that no one of the three methods offers any significant computational advantages over the other two.

  8. Analytical Chemistry with Silica Sol-Gels: Traditional Routes to New Materials for Chemical Analysis

    NASA Astrophysics Data System (ADS)

    Walcarius, Alain; Collinson, Maryanne M.

    2009-07-01

    The versatility of sol-gel chemistry enables us to generate a wide range of silica and organosilica materials with controlled structure, composition, morphology and porosity. These materials’ hosting and recognition properties, as well as their wide-open structures containing many easily accessible active sites, make them particularly attractive for analytical purposes. In this review, we summarize the importance of silica sol-gels in analytical chemistry by providing examples from the separation sciences, optical and electrochemical sensors, molecular imprinting, and biosensors. Recent work suggests that manipulating the structure and composition of these materials at different scales (from molecular to macromolecular states and/or from micro- to meso- and/or macroporous levels) promises to generate chemical and biochemical sensing devices with improved selectivity and sensitivity.

  9. Analytical technique to address terrorist threats by chemical weapons of mass destruction

    NASA Astrophysics Data System (ADS)

    Dempsey, Patrick M.

    1997-01-01

    Terrorism is no longer an issue without effect on the American mind. We now live with the same concerns and fears that have been commonplace in other developed and third world countries for a long time. Citizens of other countries have long lived with the specter of terrorism and now the U.S. needs to be concerned and prepared for terrorist activities.T he terrorist has the ability to cause great destructive effects by focusing their effort on unaware and unprepared civilian populations. Attacks can range from simple explosives to sophisticated nuclear, chemical and biological weapons. Intentional chemical releases of hazardous chemicals or chemical warfare agents pose a great threat because of their ready availability and/or ease of production, and their ability to cause widespread damage. As this battlefront changes from defined conflicts and enemies to unnamed terrorists, we must implement the proper analytical tools to provide a fast and efficient response. Each chemical uses in a terrorists weapon leaves behind a chemical signature that can be used to identify the materials involved and possibly lead investigators to the source and to those responsible. New tools to provide fast and accurate detection for battlefield chemical and biological agent attack are emerging. Gas chromatography/mass spectrometry (GC/MS) is one of these tools that has found increasing use by the military to respond to chemical agent attacks. As the technology becomes smaller and more portable, it can be used by law enforcement personnel to identify suspected terrorist releases and to help prepare the response; define contaminated areas for evacuation and safety concerns, identify the proper treatment of exposed or affected civilians, and suggest decontamination and cleanup procedures.

  10. Litter chemistry and chemical diversity drive ecosystem processes in forest ponds.

    PubMed

    Stoler, Aaron B; Burke, David J; Relyea, Rick A

    2016-07-01

    Research suggests that a positive relationship exists between diversity and ecological function, yet the multi-trophic effects of biodiversity remain poorly understood. The resource complementarity hypothesis suggests that increasing the trait diversity of resources provides a more complete diet for consumers, elevating consumer feeding rates. Whereas previous tests of this mechanism have measured trait diversity as the variation of single traits or the richness of functional groups, we employed a multivariate trait index to manipulate the chemical diversity of temperate tree litter species in outdoor pond mesocosms. We inoculated outdoor mesocosms with diverse and multi-trophic communities of microbial and macro-consumer species that rely on leaf litter for energy and nutrients. Litter was provided at three levels of chemical trait diversity, a constant level of species richness, and an equal representation of all litter species. Over three months, we measured more than 65 responses, and assessed the effects of litter chemical diversity and chemical trait means (i.e., community-weighted means). We found that litter chemical diversity positively correlated with decomposition rate of leaf litter, but had no effect on biomass or density of producers and consumers. However, the pond communities often responded to chemical trait means, particularly those related to nutrients, structure, and defense. Our results suggest that resource complementarity does have some effect on the release of energy and nutrients from decomposing substrates in forest ponds, but does not have multi-trophic effects. Our results further suggest that loss of tree biodiversity could affect forest ecosystem functionality, and particularly the processes occurring in and around ponds and wetlands.

  11. Diversity-oriented synthetic strategy for developing a chemical modulator of protein-protein interaction

    NASA Astrophysics Data System (ADS)

    Kim, Jonghoon; Jung, Jinjoo; Koo, Jaeyoung; Cho, Wansang; Lee, Won Seok; Kim, Chanwoo; Park, Wonwoo; Park, Seung Bum

    2016-10-01

    Diversity-oriented synthesis (DOS) can provide a collection of diverse and complex drug-like small molecules, which is critical in the development of new chemical probes for biological research of undruggable targets. However, the design and synthesis of small-molecule libraries with improved biological relevance as well as maximized molecular diversity represent a key challenge. Herein, we employ functional group-pairing strategy for the DOS of a chemical library containing privileged substructures, pyrimidodiazepine or pyrimidine moieties, as chemical navigators towards unexplored bioactive chemical space. To validate the utility of this DOS library, we identify a new small-molecule inhibitor of leucyl-tRNA synthetase-RagD protein-protein interaction, which regulates the amino acid-dependent activation of mechanistic target of rapamycin complex 1 signalling pathway. This work highlights that privileged substructure-based DOS strategy can be a powerful research tool for the construction of drug-like compounds to address challenging biological targets.

  12. Chemical and structural diversity of siRNA molecules.

    PubMed

    Nawrot, Barbara; Sipa, Katarzyna

    2006-01-01

    Short interfering RNAs (siRNAs) are 21-23 nt long double-stranded oligoribonucleotides which in mammalian cells exhibit a potency for sequence-specific gene silencing via an RNA interference (RNAi) pathway. It has been already proven that exogenous, chemically synthesized siRNA molecules are effective inhibitors of gene expression and are widely applied for analysis of protein function and proteomics-based target identification. Moreover, since their discovery siRNA molecules have been implemented as potential candidates for therapeutic applications. Variously modified siRNA molecules containing sugar modifications (2'-OMe, -F, -O-allyl, -amino, orthoesters and LNA analogues), internucleotide phospodiester bond modifications (phosphorothioates, boranophosphates), base modifications (s(2)U) as well as 3'-terminal cholesterol-conjugated constructs were investigated as potential candidates for effective inhibition of gene expression. This chapter reviews an impact of chemical and structural modifications of siRNA molecules on their serum and thermal stability, cellular and in vivo activity, cellular uptake, biodistribution and cytotoxicity. Functional analysis of chemically modified siRNA molecules allows for better understanding of the mechanism of the RNA interference process as well as demonstrates immense efforts in optimizing in vivo potency of siRNA molecules for RNAi-based drug design.

  13. DIVERSITY OF TYPE Ia SUPERNOVAE IMPRINTED IN CHEMICAL ABUNDANCES

    SciTech Connect

    Tsujimoto, Takuji; Shigeyama, Toshikazu

    2012-12-01

    A time delay of Type Ia supernova (SN Ia) explosions hinders the imprint of their nucleosynthesis on stellar abundances. However, some occasional cases give birth to stars that avoid enrichment of their chemical compositions by massive stars and thereby exhibit an SN-Ia-like elemental feature including a very low [Mg/Fe] ( Almost-Equal-To - 1). We highlight the elemental feature of Fe-group elements for two low-Mg/Fe objects detected in nearby galaxies, and propose the presence of a class of SNe Ia that yield the low abundance ratios of [Cr, Mn, Ni/Fe]. Our novel models of chemical evolution reveal that our proposed class of SNe Ia (slow SNe Ia) is associated with ones exploding on a long timescale after their stellar birth and give a significant impact on the chemical enrichment in the Large Magellanic Cloud (LMC). In the Galaxy, on the other hand, this effect is unseen due to the overwhelming enrichment by the major class of SNe Ia that explode promptly (prompt SNe Ia) and eject a large amount of Fe-group elements. This nicely explains the different [Cr, Mn, Ni/Fe] features between the two galaxies as well as the puzzling feature seen in the LMC stars exhibiting very low Ca but normal Mg abundances. Furthermore, the corresponding channel of slow SN Ia is exemplified by performing detailed nucleosynthesis calculations in the scheme of SNe Ia resulting from a 0.8 + 0.6 M{sub Sun} white dwarf merger.

  14. Studies on the chemical stability and functional group compatibility of the benzoin photolabile safety-catch linker using an analytical construct.

    PubMed

    Cano, Montserrat; Ladlow, Mark; Balasubramanian, Shankar

    2002-01-01

    A chemical stability study of the benzoin photolabile safety-catch linker (BPSC) has been carried out using a dual-linker analytical construct to establish its compatibility with a range of commonly employed solid-phase reaction conditions. As a result of this study, the dithiane-protected benzoin linker was shown to be reactive only toward strong acids and fluoride nucleophile. Furthermore, a scan of diverse functional groups thought to be unstable toward the safety-catch removal conditions has also been carried out. These data should provide assistance in future utilization of the BPSC for syntheses.

  15. Chemical diversity and antiviral potential in the pantropical Diospyros genus.

    PubMed

    Peyrat, Laure-Anne; Eparvier, Véronique; Eydoux, Cécilia; Guillemot, Jean-Claude; Stien, Didier; Litaudon, Marc

    2016-07-01

    A screening using a dengue replicon virus-cell-based assay was performed on 3563 ethyl acetate (EtOAc) extracts from different parts of 1500 plants. The screening led to the selection of species from the genus Diospyros (Ebenaceae), among which 25 species distributed in tropical areas showed significant inhibitory activity on dengue virus replication. A metabolic analysis was conducted from the UPLC-HRMS profiles of 33 biologically active and inactive plant extracts, and their metabolic proximity is presented in the form of a dendrogram. The results of the study showed that chemical similarity is not related to plant species or organ. Overall, metabolomic profiling allowed us to define large groups of extracts, comprising both active and inactive ones. Closely related profiles from active extracts might indicate that the common major components of these extracts were responsible for the antiviral activity, while the comparison of chemically similar active and inactive extracts, will permit to find compounds of interest. Eventually, the phytochemical investigation of Diospyros glans bark EtOAc extract afforded usnic acid and 7 known ursane- and lupane-type triterpenoids, among which 5 were found significantly active against dengue virus replication. The inhibitory potency of these compounds was also evaluated on a DENV-NS5 RNA-dependant RNA polymerase assay.

  16. Acid-Base Chemistry of White Wine: Analytical Characterisation and Chemical Modelling

    PubMed Central

    Prenesti, Enrico; Berto, Silvia; Toso, Simona; Daniele, Pier Giuseppe

    2012-01-01

    A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids) with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture), ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic “wine” especially adapted for testing. PMID:22566762

  17. Acid-base chemistry of white wine: analytical characterisation and chemical modelling.

    PubMed

    Prenesti, Enrico; Berto, Silvia; Toso, Simona; Daniele, Pier Giuseppe

    2012-01-01

    A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids) with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture), ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic "wine" especially adapted for testing.

  18. Chemical diversity in Indian oregano (Origanum vulgare L.).

    PubMed

    Verma, Ram S; Padalia, Rajendra C; Chauhan, Amit; Verma, Rajesh K; Yadav, Ajai K; Singh, Hemendra P

    2010-08-01

    The terpenoid composition of the essential oils of 17 different populations of Origanum vulgare L., collected from wild populations and subsequently grown under similar conditions in the sub-temperate region of the Western Himalaya, was studied. Analysis by GC (RI) and GC/MS allowed the identification of 51 components, representing 90.15 to 99.94% of the total oil. The two classes of the phenolic compounds and the monoterpenoids were predominant in all the essential oils. On the basis of the major constituents, i.e., marker compounds, and by comparison of the results with previous reports, new chemotypes could be identified. Principal component analysis was performed to determine the chemical variability within the different populations of O. vulgare collected and grown under similar conditions. Based on the marker compounds, six chemotypes with significant variations in their terpenoid profile were noticed within the 17 populations.

  19. Study of sensory diversity and redundancy to encode for chemical mixtures

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Gálvez, Agustín; Fernandez, Luis; Marco, Santiago

    2011-09-01

    Inspired by sensory diversity and redundancy at the olfactory epithelium, we have built a large chemical sensor array based on commercial MOX sensors. Different sensor families along with temperature modulation accounts for sensory diversity, whereas sensors of the same family combined with different load resistors provide redundancy to the system. To study the encoding of odor mixtures, a data collection consisting on the response of the array to 3 binary mixtures of ethanol, acetone, and butanone with 18 different concentration ratios is obtained.

  20. Genetic and chemical diversity of high mucilaginous plants of Sida complex by ISSR markers and chemical fingerprinting.

    PubMed

    Thul, Sanjog T; Srivastava, Ankit K; Singh, Subhash C; Shanker, Karuna

    2011-09-01

    A method was developed based on multiple approaches wherein DNA and chemical analysis was carried out toward differentiation of important species of Sida complex that is being used for commercial preparation. Isolated DNA samples were successfully performed through PCR amplification using ISSR markers and degree of genetic diversity among the different species of Sida is compared with that of chemical diversity. For genetic fingerprint investigation, selected 10 ISSR primers generating reproducible banding patterns were used. Among the total of 63 amplicons, 62 were recorded as polymorphic, genetic similarity index deduced from ISSR profiles ranged from 12 to 51%. Based on similarity index, S. acuta and S. rhombifolia found to be most similar (51%). High number of species-specific bands played pivotal role to delineate species at genetic level. Investigation based on HPTLC fingerprints analysis revealed 23 bands representing to characteristic chemicals and similarity index ranged from 73 to 91%. Prominent distinguishable bands were observed only in S. acuta, while S. cordifolia and S. rhombifolia shared most bands making them difficult to identify on chemical fingerprint basis. This report summarizes the genotypic and chemotypic diversity and the use of profiles for authentication of species of Sida complex.

  1. The diverse biological properties of the chemically inert noble gases.

    PubMed

    Winkler, David A; Thornton, Aaron; Farjot, Géraldine; Katz, Ira

    2016-04-01

    The noble gases represent an intriguing scientific paradox. They are extremely inert chemically but display a remarkable spectrum of clinically useful biological properties. Despite a relative paucity of knowledge of their mechanisms of action, some of the noble gases have been used successfully in the clinic. Studies with xenon have suggested that the noble gases as a class may exhibit valuable biological properties such as anaesthesia; amelioration of ischemic damage; tissue protection prior to transplantation; analgesic properties; and a potentially wide range of other clinically useful effects. Xenon has been shown to be safe in humans, and has useful pharmacokinetic properties such as rapid onset, fast wash out etc. The main limitations in wider use are that: many of the fundamental biochemical studies are still lacking; the lighter noble gases are likely to manifest their properties only under hyperbaric conditions, impractical in surgery; and administration of xenon using convectional gaseous anaesthesia equipment is inefficient, making its use very expensive. There is nonetheless a significant body of published literature on the biochemical, pharmacological, and clinical properties of noble gases but no comprehensive reviews exist that summarize their properties and the existing knowledge of their models of action at the molecular (atomic) level. This review provides such an up-to-date summary of the extensive, useful biological properties of noble gases as drugs and prospects for wider application of these atoms.

  2. Genetic diversity and chemical polymorphism of some Thymus species.

    PubMed

    Rustaiee, Ali Reza; Yavari, Alireza; Nazeri, Vahideh; Shokrpour, Majid; Sefidkon, Fatemeh; Rasouli, Musa

    2013-06-01

    To ascertain whether there are chemical and genetic relationships among some Thymus species and also to determine correlation between these two sets of data, the essential-oil composition and genetic variability of six populations of Thymus including: T. daenensis ČELAK. (two populations), T. fallax FISCH. & C.A.MEY., T. fedtschenkoi RONNIGER, T. migricus KLOKOV & DES.-SHOST., and T. vulgaris L. were analyzed by GC and GC/MS, and also by randomly amplified polymorphic DNA (RAPD). Thus, 27 individuals were analyzed using 16 RAPD primers, which generated 264 polymorphic scorable bands and volatiles isolated by distillation extraction were subjected to GC and GC/MS analyses. The yields of oils ranged from 2.1 to 3.8% (v/w), and 34 components were identified, amounting to a total percentage of 97.8-99.9%. RAPD Markers allowed a perfect distinction between the different species based on their distinctive genetic background. However, they did not show identical clustering with the volatile-oil profiles.

  3. Adsorption-desorption noise in plasmonic chemical/biological sensors in multiple analyte environment

    NASA Astrophysics Data System (ADS)

    Jakšić, Olga; Jakšić, Zoran; Matović, Jovan

    2009-05-01

    We analyzed the intrinsic noise of plasmonic sensors caused by the adsorption-desorption of gaseous analytes on the sensor surface. We analyzed a general situation when there is a larger number of different species in the environment. We developed our model and applied it to calculate various analyte mixtures, including some environmental pollutants, toxic and dangerous substances. The spectral density of mean square refractive index fluctuations follows a dependence similar to that of generation-recombination noise in photodetectors, flat at lower frequencies and sharply decreasing at higher. Some of the calculated noise levels are well within the detection range of conventional surface plasmon resonance sensors. One of the obvious conclusions is that AD noise may be an important limiting factor in monitoring process kinetics by nanoplasmonic sensors. An AD noise peak is observed in temperature dependence of mean square refractive index fluctuations, thus sensor operating temperature may be optimized to obtain larger signal to noise ratio. A significant property of AD noise is its increase with the plasmon sensor area decrease, which means that it will be even more pronounced in modern nanoplasmonic devices. Our consideration is valid both for conventional surface plasmon resonance devices and for general nanoplasmonic devices. This research could be of importance in diverse areas such as environmental sensing, homeland security, forensic applications, life sciences, etc.

  4. Evolution of Chemical Diversity in Echinocandin Lipopeptide Antifungal Metabolites

    PubMed Central

    Yue, Qun; Chen, Li; Zhang, Xiaoling; Li, Kuan; Sun, Jingzu; Liu, Xingzhong

    2015-01-01

    The echinocandins are a class of antifungal drugs that includes caspofungin, micafungin, and anidulafungin. Gene clusters encoding most of the structural complexity of the echinocandins provided a framework for hypotheses about the evolutionary history and chemical logic of echinocandin biosynthesis. Gene orthologs among echinocandin-producing fungi were identified. Pathway genes, including the nonribosomal peptide synthetases (NRPSs), were analyzed phylogenetically to address the hypothesis that these pathways represent descent from a common ancestor. The clusters share cooperative gene contents and linkages among the different strains. Individual pathway genes analyzed in the context of similar genes formed unique echinocandin-exclusive phylogenetic lineages. The echinocandin NRPSs, along with the NRPS from the inp gene cluster in Aspergillus nidulans and its orthologs, comprise a novel lineage among fungal NRPSs. NRPS adenylation domains from different species exhibited a one-to-one correspondence between modules and amino acid specificity that is consistent with models of tandem duplication and subfunctionalization. Pathway gene trees and Ascomycota phylogenies are congruent and consistent with the hypothesis that the echinocandin gene clusters have a common origin. The disjunct Eurotiomycete-Leotiomycete distribution appears to be consistent with a scenario of vertical descent accompanied by incomplete lineage sorting and loss of the clusters from most lineages of the Ascomycota. We present evidence for a single evolutionary origin of the echinocandin family of gene clusters and a progression of structural diversification in two fungal classes that diverged approximately 290 to 390 million years ago. Lineage-specific gene cluster evolution driven by selection of new chemotypes contributed to diversification of the molecular functionalities. PMID:26024901

  5. Analytical Capability of Defocused µ-SORS in the Chemical Interrogation of Thin Turbid Painted Layers

    PubMed Central

    Realini, Marco; Botteon, Alessandra; Colombo, Chiara; Noll, Sarah; Elliott, Stephen R.; Matousek, Pavel

    2016-01-01

    A recently developed micrometer-scale spatially offset Raman spectroscopy (μ-SORS) method provides a new analytical capability for investigating non-destructively the chemical composition of sub-surface, micrometer-scale thickness, diffusely scattering layers at depths beyond the reach of conventional confocal Raman microscopy. Here, we demonstrate experimentally, for the first time, the capability of μ-SORS to determine whether two detected chemical components originate from two separate layers or whether the two components are mixed together in a single layer. Such information is important in a number of areas, including conservation of cultural heritage objects, and is not available, for highly turbid media, from conventional Raman microscopy, where axial (confocal) scanning is not possible due to an inability to facilitate direct imaging within the highly scattering sample. This application constitutes an additional capability for μ-SORS in addition to its basic capacity to determine the overall chemical make-up of layers in a turbid system. PMID:26767641

  6. Exploring the role of quantum chemical descriptors in modeling acute toxicity of diverse chemicals to Daphnia magna.

    PubMed

    Reenu; Vikas

    2015-09-01

    Various quantum-mechanically computed molecular and thermodynamic descriptors along with physico-chemical, electrostatic and topological descriptors are compared while developing quantitative structure-activity relationships (QSARs) for the acute toxicity of 252 diverse organic chemicals towards Daphnia magna. QSAR models based on the quantum-chemical descriptors, computed with routinely employed advanced semi-empirical and ab-initio methods, along with the electron-correlation contribution (CORR) of the descriptors, are analyzed for the external predictivity of the acute toxicity. The models with reliable internal stability and external predictivity are found to be based on the HOMO energy along with the physico-chemical, electrostatic and topological descriptors. Besides this, the total energy and electron-correlation energy are also observed as highly reliable descriptors, suggesting that the intra-molecular interactions between the electrons play an important role in the origin of the acute toxicity, which is in fact an unexplored phenomenon. The models based on quantum-chemical descriptors such as chemical hardness, absolute electronegativity, standard Gibbs free energy and enthalpy are also observed to be reliable. A comparison of the robust models based on the quantum-chemical descriptors computed with various quantum-mechanical methods suggests that the advanced semi-empirical methods such as PM7 can be more reliable than the ab-initio methods which are computationally more expensive.

  7. Metabolite induction via microorganism co-culture: a potential way to enhance chemical diversity for drug discovery.

    PubMed

    Bertrand, Samuel; Bohni, Nadine; Schnee, Sylvain; Schumpp, Olivier; Gindro, Katia; Wolfender, Jean-Luc

    2014-11-01

    Microorganisms have a long track record as important sources of novel bioactive natural products, particularly in the field of drug discovery. While microbes have been shown to biosynthesize a wide array of molecules, recent advances in genome sequencing have revealed that such organisms have the potential to yield even more structurally diverse secondary metabolites. Thus, many microbial gene clusters may be silent under standard laboratory growth conditions. In the last ten years, several methods have been developed to aid in the activation of these cryptic biosynthetic pathways. In addition to the techniques that demand prior knowledge of the genome sequences of the studied microorganisms, several genome sequence-independent tools have been developed. One of these approaches is microorganism co-culture, involving the cultivation of two or more microorganisms in the same confined environment. Microorganism co-culture is inspired by the natural microbe communities that are omnipresent in nature. Within these communities, microbes interact through signaling or defense molecules. Such compounds, produced dynamically, are of potential interest as new leads for drug discovery. Microorganism co-culture can be achieved in either solid or liquid media and has recently been used increasingly extensively to study natural interactions and discover new bioactive metabolites. Because of the complexity of microbial extracts, advanced analytical methods (e.g., mass spectrometry methods and metabolomics) are key for the successful detection and identification of co-culture-induced metabolites. This review focuses on co-culture studies that aim to increase the diversity of metabolites obtained from microbes. The various strategies are summarized with a special emphasis on the multiple methods of performing co-culture experiments. The analytical approaches for studying these interaction phenomena are discussed, and the chemical diversity and biological activity observed among the

  8. Chiral Separation of G-type Chemical Warfare Nerve Agents via Analytical Supercritical Fluid Chromatography

    PubMed Central

    Kasten, Shane A; Zulli, Steven; Jones, Jonathan L; Dephillipo, Thomas; Cerasoli, Douglas M

    2014-01-01

    Chemical warfare nerve agents (CWNAs) are extremely toxic organophosphorus compounds that contain a chiral phosphorus center. Undirected synthesis of G-type CWNAs produces stereoisomers of tabun, sarin, soman, and cyclosarin (GA, GB, GD, and GF, respectively). Analytical-scale methods were developed using a supercritical fluid chromatography (SFC) system in tandem with a mass spectrometer for the separation, quantitation, and isolation of individual stereoisomers of GA, GB, GD, and GF. Screening various chiral stationary phases (CSPs) for the capacity to provide full baseline separation of the CWNAs revealed that a Regis WhelkO1 (SS) column was capable of separating the enantiomers of GA, GB, and GF, with elution of the P(+) enantiomer preceding elution of the corresponding P(–) enantiomer; two WhelkO1 (SS) columns had to be connected in series to achieve complete baseline resolution. The four diastereomers of GD were also resolved using two tandem WhelkO1 (SS) columns, with complete baseline separation of the two P(+) epimers. A single WhelkO1 (RR) column with inverse stereochemistry resulted in baseline separation of the GD P(–) epimers. The analytical methods described can be scaled to allow isolation of individual stereoisomers to assist in screening and development of countermeasures to organophosphorus nerve agents. Chirality 26:817–824, 2014. © 2014 The Authors. Chirality published by John Wiley Periodicals, Inc. PMID:25298066

  9. Chiral separation of G-type chemical warfare nerve agents via analytical supercritical fluid chromatography.

    PubMed

    Kasten, Shane A; Zulli, Steven; Jones, Jonathan L; Dephillipo, Thomas; Cerasoli, Douglas M

    2014-12-01

    Chemical warfare nerve agents (CWNAs) are extremely toxic organophosphorus compounds that contain a chiral phosphorus center. Undirected synthesis of G-type CWNAs produces stereoisomers of tabun, sarin, soman, and cyclosarin (GA, GB, GD, and GF, respectively). Analytical-scale methods were developed using a supercritical fluid chromatography (SFC) system in tandem with a mass spectrometer for the separation, quantitation, and isolation of individual stereoisomers of GA, GB, GD, and GF. Screening various chiral stationary phases (CSPs) for the capacity to provide full baseline separation of the CWNAs revealed that a Regis WhelkO1 (SS) column was capable of separating the enantiomers of GA, GB, and GF, with elution of the P(+) enantiomer preceding elution of the corresponding P(-) enantiomer; two WhelkO1 (SS) columns had to be connected in series to achieve complete baseline resolution. The four diastereomers of GD were also resolved using two tandem WhelkO1 (SS) columns, with complete baseline separation of the two P(+) epimers. A single WhelkO1 (RR) column with inverse stereochemistry resulted in baseline separation of the GD P(-) epimers. The analytical methods described can be scaled to allow isolation of individual stereoisomers to assist in screening and development of countermeasures to organophosphorus nerve agents.

  10. Statistically testing the validity of analytical and computational approximations to the chemical master equation.

    PubMed

    Jenkinson, Garrett; Goutsias, John

    2013-05-28

    The master equation is used extensively to model chemical reaction systems with stochastic dynamics. However, and despite its phenomenological simplicity, it is not in general possible to compute the solution of this equation. Drawing exact samples from the master equation is possible, but can be computationally demanding, especially when estimating high-order statistical summaries or joint probability distributions. As a consequence, one often relies on analytical approximations to the solution of the master equation or on computational techniques that draw approximative samples from this equation. Unfortunately, it is not in general possible to check whether a particular approximation scheme is valid. The main objective of this paper is to develop an effective methodology to address this problem based on statistical hypothesis testing. By drawing a moderate number of samples from the master equation, the proposed techniques use the well-known Kolmogorov-Smirnov statistic to reject the validity of a given approximation method or accept it with a certain level of confidence. Our approach is general enough to deal with any master equation and can be used to test the validity of any analytical approximation method or any approximative sampling technique of interest. A number of examples, based on the Schlögl model of chemistry and the SIR model of epidemiology, clearly illustrate the effectiveness and potential of the proposed statistical framework.

  11. Can phylogeny predict chemical diversity and potential medicinal activity of plants? A case study of Amaryllidaceae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During evolution, plants and other organisms have developed a diversity of chemical defences, leading to the evolution of various groups of specialized metabolites selected for their endogenous biological function. A correlation between phylogeny and biosynthetic pathways could offer a predictive ap...

  12. Using the gini coefficient to measure the chemical diversity of small-molecule libraries.

    PubMed

    Weidlich, Iwona E; Filippov, Igor V

    2016-08-15

    Modern databases of small organic molecules contain tens of millions of structures. The size of theoretically available chemistry is even larger. However, despite the large amount of chemical information, the "big data" moment for chemistry has not yet provided the corresponding payoff of cheaper computer-predicted medicine or robust machine-learning models for the determination of efficacy and toxicity. Here, we present a study of the diversity of chemical datasets using a measure that is commonly used in socioeconomic studies. We demonstrate the use of this diversity measure on several datasets that were constructed to contain various congeneric subsets of molecules as well as randomly selected molecules. We also apply our method to a number of well-known databases that are frequently used for structure-activity relationship modeling. Our results show the poor diversity of the common sources of potential lead compounds compared to actual known drugs. © 2016 Wiley Periodicals, Inc.

  13. Standardization of chemical analytical techniques for pyrolysis bio-oil: history, challenges, and current status of methods: Bio-oil Analytical Standardization

    SciTech Connect

    Ferrell, Jack R.; Olarte, Mariefel V.; Christensen, Earl D.; Padmaperuma, Asanga B.; Connatser, Raynella M.; Stankovikj, Filip; Meier, Dietrich; Paasikallio, Ville

    2016-07-05

    In this perspective, we discuss the standardization of analytical techniques for pyrolysis bio-oils, including the current status of methods, and our opinions on future directions. First, the history of past standardization efforts is summarized, and both successful and unsuccessful validation of analytical techniques highlighted. The majority of analytical standardization studies to-date has tested only physical characterization techniques. Here, we present results from an international round robin on the validation of chemical characterization techniques for bio-oils. Techniques tested included acid number, carbonyl titrations using two different methods (one at room temperature and one at 80 degrees C), 31P NMR for determination of hydroxyl groups, and a quantitative gas chromatography-mass spectrometry (GC-MS) method. Both carbonyl titration and acid number methods have yielded acceptable inter-laboratory variabilities. 31P NMR produced acceptable results for aliphatic and phenolic hydroxyl groups, but not for carboxylic hydroxyl groups. As shown in previous round robins, GC-MS results were more variable. Reliable chemical characterization of bio-oils will enable upgrading research and allow for detailed comparisons of bio-oils produced at different facilities. Reliable analytics are also needed to enable an emerging bioenergy industry, as processing facilities often have different analytical needs and capabilities than research facilities. We feel that correlations in reliable characterizations of bio-oils will help strike a balance between research and industry, and will ultimately help to determine metrics for bio-oil quality. Finally, the standardization of additional analytical methods is needed, particularly for upgraded bio-oils.

  14. Predicting carcinogenicity of diverse chemicals using probabilistic neural network modeling approaches

    SciTech Connect

    Singh, Kunwar P.; Gupta, Shikha; Rai, Premanjali

    2013-10-15

    Robust global models capable of discriminating positive and non-positive carcinogens; and predicting carcinogenic potency of chemicals in rodents were developed. The dataset of 834 structurally diverse chemicals extracted from Carcinogenic Potency Database (CPDB) was used which contained 466 positive and 368 non-positive carcinogens. Twelve non-quantum mechanical molecular descriptors were derived. Structural diversity of the chemicals and nonlinearity in the data were evaluated using Tanimoto similarity index and Brock–Dechert–Scheinkman statistics. Probabilistic neural network (PNN) and generalized regression neural network (GRNN) models were constructed for classification and function optimization problems using the carcinogenicity end point in rat. Validation of the models was performed using the internal and external procedures employing a wide series of statistical checks. PNN constructed using five descriptors rendered classification accuracy of 92.09% in complete rat data. The PNN model rendered classification accuracies of 91.77%, 80.70% and 92.08% in mouse, hamster and pesticide data, respectively. The GRNN constructed with nine descriptors yielded correlation coefficient of 0.896 between the measured and predicted carcinogenic potency with mean squared error (MSE) of 0.44 in complete rat data. The rat carcinogenicity model (GRNN) applied to the mouse and hamster data yielded correlation coefficient and MSE of 0.758, 0.71 and 0.760, 0.46, respectively. The results suggest for wide applicability of the inter-species models in predicting carcinogenic potency of chemicals. Both the PNN and GRNN (inter-species) models constructed here can be useful tools in predicting the carcinogenicity of new chemicals for regulatory purposes. - Graphical abstract: Figure (a) shows classification accuracies (positive and non-positive carcinogens) in rat, mouse, hamster, and pesticide data yielded by optimal PNN model. Figure (b) shows generalization and predictive

  15. An analytic model of axisymmetric mantle plume due to thermal and chemical diffusion

    NASA Technical Reports Server (NTRS)

    Liu, Mian; Chase, Clement G.

    1990-01-01

    An analytic model of axisymmetric mantle plumes driven by either thermal diffusion or combined diffusion of both heat and chemical species from a point source is presented. The governing equations are solved numerically in cylindrical coordinates for a Newtonian fluid with constant viscosity. Instead of starting from an assumed plume source, constraints on the source parameters, such as the depth of the source regions and the total heat input from the plume sources, are deduced using the geophysical characteristics of mantle plumes inferred from modelling of hotspot swells. The Hawaiian hotspot and the Bermuda hotspot are used as examples. Narrow mantle plumes are expected for likely mantle viscosities. The temperature anomaly and the size of thermal plumes underneath the lithosphere can be sensitive indicators of plume depth. The Hawaiian plume is likely to originate at a much greater depth than the Bermuda plume. One suggestive result puts the Hawaiian plume source at a depth near the core-mantle boundary and the source of the Bermuda plume in the upper mantle, close to the 700 km discontinuity. The total thermal energy input by the source region to the Hawaiian plume is about 5 x 10(10) watts. The corresponding diameter of the source region is about 100 to 150 km. Chemical diffusion from the same source does not affect the thermal structure of the plume.

  16. Chemical and mineralogical characterizations of LD converter steel slags: A multi-analytical techniques approach

    SciTech Connect

    Waligora, J.; Bulteel, D.; Degrugilliers, P.; Damidot, D.; Potdevin, J.L.; Measson, M.

    2010-01-15

    The use of LD converter steel slags (coming from Linz-Donawitz steelmaking process) as aggregates in road construction can in certain cases lead to dimensional damage due to a macroscopic swelling that is the consequence of chemical reactions. The aim of this study was to couple several analytical techniques in order to carefully undertake chemical and mineralogical characterizations of LD steel slags and identify the phases that are expected to be responsible for their instability. Optical microscopy, scanning electron microscopy and electron probe microanalyses revealed that LD steel slags mainly contain calcium silicates, dicalcium ferrites, iron oxides and lime. However, as a calcium silicate phase is heterogeneous, Raman microspectrometry and transmitted electron microscopy had to be used to characterize it more precisely. Results showed that lime is present under two forms in slag grains: some nodules observed in the matrix whose size ranges from 20 to 100 {mu}m and some micro-inclusions, enclosed in the heterogeneous calcium silicate phase whose size ranges from 1 to 3 {mu}m. It was also established that without the presence of magnesia, lime is expected to be the only phase responsible for LD steel slags instability. Nevertheless, the distribution of lime between nodules and micro-inclusions may play a major role and could explain that similar amounts of lime can induce different instabilities. Thus, it appears that lime content of LD steel slags is not the only parameter to explain their instability.

  17. A Simplified Analytic Investigation of the Riverside Effects of Sediment Diversions

    DTIC Science & Technology

    2013-09-01

    demonstrated that the river bed consists of a sand layer of variable thickness, underlain by erosion resistant strata (either relict glacial deposits...CHETN-VII-13 September 2013 14  Short term effects include the redistribution of sediment by erosion upstream of the diversion to deposition...does change, such that it is larger for erosional conditions and smaller for depositional conditions. But, for simplicity, the equilibrium value of r

  18. Dynamic-chemical evolution of the early protoplanetary disk and chemical diversity of asteroids

    NASA Astrophysics Data System (ADS)

    Nagahara, Hiroko

    2015-08-01

    Evolution of a protoplanetary disk is dynamic, where angular momentum is transported outward whereas masses are inward. Although the overall material transport is inward, a significant amount of outward transporation occurs due to diffusion, which resulted in mixing of materials with different degree of thermal processing.In the present study, we investigate the mixing of materials in a protoplanetary disk by combining fluid dynamics and themodynamics, and discuss the chemical evolution of the disk as a function of time and space and the conditions to generate chemical heterogeneity in the 2-4 AU within 106 years.The essence of the model is of a standard disk evolution model, which is combined with particle tracking model by Ciesla (2010). It enables us to track all the movement of individual particles. The chemical composition of dust particles is assumed with chemical equilibrium calculation. Summing up the number of grains with different chemical compositions, we trace the temporal and spatial change of chemical composition of the disk.The results show that some fraction of dust grains were transported to ~13AU after 105 years, ~50 AU after 5x105 years, and ~100 AU after a million years, though the most of them were fallen into the proto-sun. The flux of inward and outward dust transportation is significant within 105 years. The chemical composition of the disk is relatively enriched in refractory elements due to the outward transport of significant amounts of grains heated to high temperatures, and more heterogeneous at the early stage due to various degree of mixing of high temperature and low temperature components. It becomes homogeneous with unfractionated composition with time.Carbonaceous chondrites are thought to be fragments of asteroids, which are remnants of planetesimals. The chemical composition of carbonaceous chondrites are successfully reproduced with the present model, but only at the early stage of disk evolution (<105 years) unless the disk

  19. Phylogenetic and chemical diversity of fungal endophytes isolated from Silybum marianum (L) Gaertn. (milk thistle)

    PubMed Central

    Raja, Huzefa A.; Kaur, Amninder; El-Elimat, Tamam; Figueroa, Mario; Kumar, Rahul; Deep, Gagan; Agarwal, Rajesh; Faeth, Stanley H.; Cech, Nadja B.; Oberlies, Nicholas H.

    2015-01-01

    Use of the herb milk thistle (Silybum marianum) is widespread, and its chemistry has been studied for over 50 years. However, milk thistle endophytes have not been studied previously for their fungal and chemical diversity. We examined the fungal endophytes inhabiting this medicinal herb to determine: (1) species composition and phylogenetic diversity of fungal endophytes; (2) chemical diversity of secondary metabolites produced by these organisms; and (3) cytotoxicity of the pure compounds against the human prostate carcinoma (PC-3) cell line. Forty-one fungal isolates were identified from milk thistle comprising 25 operational taxonomic units based on BLAST search via GenBank using published authentic sequences from nuclear ribosomal internal transcribed spacer sequence data. Maximum likelihood analyses of partial 28S rRNA gene showed that these endophytes had phylogenetic affinities to four major classes of Ascomycota, the Dothideomycetes, Sordariomycetes, Eurotiomycetes, and Leotiomycetes. Chemical studies of solid–substrate fermentation cultures led to the isolation of four new natural products. In addition, 58 known secondary metabolites, representing diverse biosynthetic classes, were isolated and characterized using a suite of nuclear magnetic resonance and mass spectrometry techniques. Selected pure compounds were tested against the PC-3 cell line, where six compounds displayed cytotoxicity. PMID:26000195

  20. Chemical composition of inks of diverse marine molluscs suggests convergent chemical defenses.

    PubMed

    Derby, Charles D; Kicklighter, Cynthia E; Johnson, P M; Zhang, Xu

    2007-05-01

    Some marine molluscs, notably sea hares, cuttlefish, squid, and octopus, release ink when attacked by predators. The sea hare Aplysia californica releases secretions from the ink gland and opaline gland that protect individuals from injury or death from predatory spiny lobsters through a combination of mechanisms that include chemical deterrence, sensory disruption, and phagomimicry. The latter two mechanisms are facilitated by millimolar concentrations of free amino acids (FAA) in sea hare ink and opaline, which stimulate the chemosensory systems of predators, ultimately leading to escape by sea hares. We hypothesize that other inking molluscs use sensory disruption and/or phagomimicry as a chemical defense. To investigate this, we examined concentrations of 21 FAA and ammonium in the defensive secretions of nine species of inking molluscs: three sea hares (Aplysia californica, Aplysia dactylomela, Aplysia juliana) and six cephalopods (cuttlefish: Sepia officinalis; squid: Loligo pealei, Lolliguncula brevis, Dosidicus gigas; octopus: Octopus vulgaris, Octopus bimaculoides). We found millimolar levels of total FAA and ammonium in these secretions, and the FAA in highest concentration were taurine, aspartic acid, glutamic acid, alanine, and lysine. Crustaceans and fish, which are major predators of these molluscs, have specific receptor systems for these FAA. Our chemical analysis supports the hypothesis that inking molluscs have the potential to use sensory disruption and/or phagomimicry as a chemical defense.

  1. Spatio-temporal analysis of industrial composition with IVIID: an interactive visual analytics interface for industrial diversity

    NASA Astrophysics Data System (ADS)

    Mack, Elizabeth A.; Zhang, Yifan; Rey, Sergio; Maciejewski, Ross

    2014-04-01

    The industrial composition of places has received considerable attention because of the widespread belief that industrial diversity buffers regional economies from economic shocks. Subsequently, a variety of toolkits and indices have been developed with the goal of better capturing the compositional dynamics of regions. Although useful, a key drawback of these indices is their static nature, which limits the utility of these indices in a space-time context. This paper provides an overview of and applications of an interface called interactive visualization tool for indices of industrial diversity, which is a visual analytics tool developed specifically for the analysis and visualization of local measures of industrial composition for areal data. This overview will include a discussion of its key features, as well as a demonstration of the utility of the interface in exploring questions surrounding diversity and the dynamic nature of composition through space and time. A focus of this demonstration is to highlight how the interactivity and query functionality of this interface overcome several of the obstacles to understanding composition through space and time that prior toolkits and comparative static approaches have been unable to address.

  2. Multidimensional metrics of niche space for use with diverse analytical techniques

    PubMed Central

    Bowes, Rachel E.; Thorp, James H.; Reuman, Daniel C.

    2017-01-01

    Multidimensional data are integral to many community-ecological studies and come in various forms, such as stable isotopes, compound specific analyses (e.g., amino acids and fatty acids), and both biodiversity and life history traits. Scientists employing such data often lack standardized metrics to evaluate communities in niche space where more than 2 dimensions are involved. To alleviate this problem, we developed a graphing and analytical approach for use with more than two variables, based on previously established stable isotope bi-plot metrics. We introduce here our community metrics as R scripts. By extending the original metrics to multiple dimensions, we created n-dimensional plots and metrics to characterize any set of quantitative measurements of a community. We demonstrate the utility of these metrics using stable isotope data; however, the approaches are applicable to many types of data. The resulting metrics provide more and better information compared to traditional analytic frameworks. The approach can be applied in many branches of community ecology, and it offers accessible metrics to quantitatively analyze the structure of communities across ecosystems and through time. PMID:28145524

  3. Diversity-oriented synthetic strategy for developing a chemical modulator of protein–protein interaction

    PubMed Central

    Kim, Jonghoon; Jung, Jinjoo; Koo, Jaeyoung; Cho, Wansang; Lee, Won Seok; Kim, Chanwoo; Park, Wonwoo; Park, Seung Bum

    2016-01-01

    Diversity-oriented synthesis (DOS) can provide a collection of diverse and complex drug-like small molecules, which is critical in the development of new chemical probes for biological research of undruggable targets. However, the design and synthesis of small-molecule libraries with improved biological relevance as well as maximized molecular diversity represent a key challenge. Herein, we employ functional group-pairing strategy for the DOS of a chemical library containing privileged substructures, pyrimidodiazepine or pyrimidine moieties, as chemical navigators towards unexplored bioactive chemical space. To validate the utility of this DOS library, we identify a new small-molecule inhibitor of leucyl-tRNA synthetase–RagD protein–protein interaction, which regulates the amino acid-dependent activation of mechanistic target of rapamycin complex 1 signalling pathway. This work highlights that privileged substructure-based DOS strategy can be a powerful research tool for the construction of drug-like compounds to address challenging biological targets. PMID:27774980

  4. Limited Influence of Oxygen on the Evolution of Chemical Diversity in Metabolic Networks

    PubMed Central

    Takemoto, Kazuhiro; Yoshitake, Ikumi

    2013-01-01

    Oxygen is thought to promote species and biomolecule diversity. Previous studies have suggested that oxygen expands metabolic networks by acquiring metabolites with different chemical properties (higher hydrophobicity, for example). However, such conclusions are typically based on biased evaluation, and are therefore non-conclusive. Thus, we re-investigated the effect of oxygen on metabolic evolution using a phylogenetic comparative method and metadata analysis to reduce the bias as much as possible. Notably, we found no difference in metabolic network expansion between aerobes and anaerobes when evaluating phylogenetic relationships. Furthermore, we showed that previous studies have overestimated or underestimated the degrees of differences in the chemical properties (e.g., hydrophobicity) between oxic and anoxic metabolites in metabolic networks of unicellular organisms; however, such overestimation was not observed when considering the metabolic networks of multicellular organisms. These findings indicate that the contribution of oxygen to increased chemical diversity in metabolic networks is lower than previously thought; rather, phylogenetic signals and cell-cell communication result in increased chemical diversity. However, this conclusion does not contradict the effect of oxygen on metabolic evolution; instead, it provides a deeper understanding of how oxygen contributes to metabolic evolution despite several limitations in data analysis methods. PMID:24958261

  5. A combined analytical solution for Chemical Exchange Saturation Transfer and semi-solid Magnetization Transfer

    PubMed Central

    Zaiss, Moritz; Zu, Zhongliang; Xu, Junzhong; Schuenke, Patrick; Gochberg, Daniel F.; Gore, John C.; Ladd, Mark E.; Bachert, Peter

    2015-01-01

    Off-resonant radiofrequency irradiation in tissue indirectly lowers the water signal by saturation transfer processes: On the one hand, there are selective chemical exchange saturation transfer (CEST) effects originating from exchanging endogenous protons resonating a few ppm from water; on the other hand, there is the broad semi-solid magnetization transfer (MT) originating from immobile protons associated with the tissue matrix with kHz line-widths. Recently it was shown that endogenous CEST contrasts can be strongly affected by the MT background so that corrections are needed to derive accurate estimates of CEST effects. Herein we show that a full analytical solution of the underlying Bloch-McConnell equations for both MT and CEST provides insights into their interaction and suggests a simple means to isolate their effects. The presented analytical solution, based on the eigenspace solution of the Bloch-McConnell equations, extends previous treatments by allowing arbitrary line-shapes for the semi-solid MT effects and simultaneously describing multiple CEST pools in the presence of a large MT pool for arbitrary irradiation. The structure of the model indicates that semi-solid MT and CEST effects basically add up inversely in determining the steady-state Z-spectrum, as previously shown for direct saturation and CEST effects. Implications for existing previous CEST analyses in the presence of a semi-solid MT are studied and discussed. It turns out that to accurately quantify CEST contrast, a good reference Z-value, the observed longitudinal relaxation rate of water, and the semi-solid MT pool size fraction, must all be known. PMID:25504828

  6. Formation of Metal-Adducted Analyte Ions by Flame-Induced Atmospheric Pressure Chemical Ionization Mass Spectrometry.

    PubMed

    Cheng, Sy-Chyi; Wang, Chin-Hsiung; Shiea, Jentaie

    2016-05-17

    A flame-induced atmospheric pressure chemical ionization (FAPCI) source, consisting of a miniflame, nebulizer, and heated tube, was developed to ionize analytes. The ionization was performed by reacting analytes with a charged species generated in a flame. A stainless steel needle deposited with saturated alkali chloride solution was introduced into the mini oxyacetylene flame to generate alkali ions, which were reacted with analytes (M) generated in a heated nebulizer. The alkali-adducted 18-crown-6 ether ions, including (M + Li)(+), (M + Na)(+), (M + K)(+), (M + Rb)(+), and (M + Cs)(+), were successfully detected on the FAPCI mass spectra when the corresponding alkali chloride solutions were separately introduced to the flame. When an alkali chloride mixture was introduced, all alkali-adducted analyte ions were simultaneously detected. Their intensity order was as follows: (M + Cs)(+) > (M + Rb)(+) > (M + K)(+) > (M + Na)(+) > (M + Li)(+), and this trend agreed with the lattice energies of alkali chlorides. Besides alkali ions, other transition metal ions such as Ni(+), Cu(+), and Ag(+) were generated in a flame for analyte ionization. Other than metal ions, the reactive species generated in the fossil fuel flame could also be used to ionize analytes, which formed protonated analyte ions (M + H)(+) in positive ion mode and deprotonated analyte ions (M - H)(-) in negative ion mode.

  7. HIV diversity and drug resistance from plasma and non-plasma analytes in a large treatment programme in western Kenya

    PubMed Central

    Kantor, Rami; DeLong, Allison; Balamane, Maya; Schreier, Leeann; Lloyd, Robert M; Injera, Wilfred; Kamle, Lydia; Mambo, Fidelis; Muyonga, Sarah; Katzenstein, David; Hogan, Joseph; Buziba, Nathan; Diero, Lameck

    2014-01-01

    Introduction Antiretroviral resistance leads to treatment failure and resistance transmission. Resistance data in western Kenya are limited. Collection of non-plasma analytes may provide additional resistance information. Methods We assessed HIV diversity using the REGA tool, transmitted resistance by the WHO mutation list and acquired resistance upon first-line failure by the IAS–USA mutation list, at the Academic Model Providing Access to Healthcare (AMPATH), a major treatment programme in western Kenya. Plasma and four non-plasma analytes, dried blood-spots (DBS), dried plasma-spots (DPS), ViveSTTM-plasma (STP) and ViveST-blood (STB), were compared to identify diversity and evaluate sequence concordance. Results Among 122 patients, 62 were treatment-naïve and 60 treatment-experienced; 61% were female, median age 35 years, median CD4 182 cells/µL, median viral-load 4.6 log10 copies/mL. One hundred and ninety-six sequences were available for 107/122 (88%) patients, 58/62 (94%) treatment-naïve and 49/60 (82%) treated; 100/122 (82%) plasma, 37/78 (47%) attempted DBS, 16/45 (36%) attempted DPS, 14/44 (32%) attempted STP from fresh plasma and 23/34 (68%) from frozen plasma, and 5/42 (12%) attempted STB. Plasma and DBS genotyping success increased at higher VL and shorter shipment-to-genotyping time. Main subtypes were A (62%), D (15%) and C (6%). Transmitted resistance was found in 1.8% of plasma sequences, and 7% combining analytes. Plasma resistance mutations were identified in 91% of treated patients, 76% NRTI, 91% NNRTI; 76% dual-class; 60% with intermediate-high predicted resistance to future treatment options; with novel mutation co-occurrence patterns. Nearly 88% of plasma mutations were identified in DBS, 89% in DPS and 94% in STP. Of 23 discordant mutations, 92% in plasma and 60% in non-plasma analytes were mixtures. Mean whole-sequence discordance from frozen plasma reference was 1.1% for plasma-DBS, 1.2% plasma-DPS, 2.0% plasma-STP and 2.3% plasma

  8. Synthesis and chemical diversity analysis of bicyclo[3.3.1]non-3-en-2-ones

    PubMed Central

    Hammill, Jared T.; Contreras-García, Julia; Virshup, Aaron M.; Beratan, David; Yang, Weitao

    2010-01-01

    Functionalized bicyclo[3.3.1]non-3-en-2-ones are obtained from commercially available phenols by a hypervalent iodine oxidation, enone epoxidation, epoxide thiolysis, and intramolecular aldol reaction sequence. Reaction optimization studies identified room temperature as well as microwave-mediated procedures, providing moderate to good yields (57%-88%) in the thiophenol-mediated epoxide opening and intramolecular aldol reaction. In addition, the isolation of a key intermediate and in situ NMR studies supported the mechanistic hypothesis. The bicyclic ring products occupy novel chemical space according to ChemGPS and Chemaxon chemical diversity and cheminformatics analyses. PMID:20798897

  9. Chemical diversity as a function of temperature in six northern diatom species.

    PubMed

    Huseby, Siv; Degerlund, Maria; Eriksen, Gunilla K; Ingebrigtsen, Richard A; Eilertsen, Hans Chr; Hansen, Espen

    2013-10-30

    In this study, we investigate how metabolic fingerprints are related to temperature. Six common northern temperate diatoms (Attheya longicornis, Chaetoceros socialis, Chaetoceros furcellatus, Porosira glacialis, Skeletonema marinoi, and Thalassiosira gravida) were cultivated at two different temperatures, 0.5 and 8.5 °C. To exclude metabolic variations due to differences in growth rates, the growth rates were kept similar by performing the experiments under light limited conditions but in exponential growth phase. Growth rates and maximum quantum yield of photosynthesis were measured and interpreted as physiological variables, and metabolic fingerprints were acquired by high-resolution mass spectrometry. The chemical diversity varied substantially between the two temperatures for the tested species, ranging from 31% similarity for C. furcellatus and P. glacialis to 81% similarity for A. longicornis. The chemical diversity was generally highest at the lowest temperature.

  10. Chemical screening: a simple approach to visualizing Streptomyces diversity for drug discovery and further research.

    PubMed

    Taddei, Antonieta; Valderrama, Margaret; Giarrizzo, Juan; Rey, Maikahl; Castelli, Cristina

    2006-04-01

    The morphological and biochemical characteristics of Streptomyces species tend to be very similar, and thus the elucidation of their diversity is both time- and money-consuming. Here we evaluated various streptomycetes isolates using a chemical screening approach in order to establish their secondary metabolite patterns, thereby avoiding the possible discounting of morphologically similar strains. Results demonstrated that each isolate presented a unique pattern of secondary metabolites independently of their morphological and biochemical characteristics. We also established the enormous diversity in metabolic products among our isolates, and thus many potentially new metabolites may be studied in further research. Our results indicate that chemical screening is a simple selection method for recognizing the specific fingerprint of each isolate, highlighting the particular metabolic characteristics of each with respect to the other studied strains.

  11. Use of a biosynthetic intermediate to explore the chemical diversity of pseudo-natural fungal polyketides

    NASA Astrophysics Data System (ADS)

    Asai, Teigo; Tsukada, Kento; Ise, Satomi; Shirata, Naoki; Hashimoto, Makoto; Fujii, Isao; Gomi, Katsuya; Nakagawara, Kosuke; Kodama, Eiichi N.; Oshima, Yoshiteru

    2015-09-01

    The structural complexity and diversity of natural products make them attractive sources for potential drug discovery, with their characteristics being derived from the multi-step combination of enzymatic and non-enzymatic conversions of intermediates in each biosynthetic pathway. Intermediates that exhibit multipotent behaviour have great potential for use as starting points in diversity-oriented synthesis. Inspired by the biosynthetic pathways that form complex metabolites from simple intermediates, we developed a semi-synthetic process that combines heterologous biosynthesis and artificial diversification. The heterologous biosynthesis of fungal polyketide intermediates led to the isolation of novel oligomers and provided evidence for ortho-quinonemethide equivalency in their isochromene form. The intrinsic reactivity of the isochromene polyketide enabled us to access various new chemical entities by modifying and remodelling the polyketide core and through coupling with indole molecules. We thus succeeded in generating exceptionally diverse pseudo-natural polyketides through this process and demonstrated an advanced method of using biosynthetic intermediates.

  12. Analytical model of chemical phase and formation of DSB in chromosomes by ionizing radiation.

    PubMed

    Barilla, Jiří; Lokajíček, Miloš; Pisaková, Hana; Simr, Pavel

    2013-03-01

    Mathematical analytical model of the processes running in individual radical clusters during the chemical phase (under the presence of radiomodifiers) proposed by us earlier has been further developed and improved. It has been applied to the data presented by Blok and Loman characterizing the oxygen effect in SSB and DSB formation (in water solution and at low-LET radiation) also in the region of very small oxygen concentrations, which cannot be studied with the help of experiments done with living cells. In this new analysis the values of all reaction rates and diffusion parameters known from literature have been made use of. The great increase of SSB and DSB at zero oxygen concentration may follow from the fact that at small oxygen concentrations the oxygen absorbs other radicals while at higher concentrations the formation of oxygen radicals prevails. It explains the double oxygen effect found already earlier by Ewing. The model may be easily extended to include also the effects of other radiomodifiers present in medium during irradiation.

  13. Odor intensity and characterization of jet exhaust and chemical analytical measurements

    NASA Technical Reports Server (NTRS)

    Kendall, D. A.; Levins, P. L.

    1973-01-01

    Odor and chemical analyses were carried out on the exhaust samples from a J-57 combustor can operated over a range of inlet conditions, and with several fuel types and nozzle modifications. The odor characteristics and total intensity of odor for each exhaust were determined over a range of dilutions to allow for a least squares determination of the intensity at 1,000 to 1 dilutions. Analytical measures included the concentration of total hydrocarbons and the concentrations of aromatic organic species and oxygenated organic species from collected samples which were taken concurrently. A correlation was found between the concentration of the odorous oxygenated fraction and the total intensity of aroma. Inlet operating conditions and nozzle modifications which increase the efficiency of combustion as measured by exhaust gas analyses reduce the odor intensity and the quantity of oxygenates in the exhaust. The type of fuel burned altered the intensity of odor in relation to the quantity of oxygenates produced and, in some instances, changed the odor character.

  14. Diversity synthesis of tetrahydroprotoberberines glycosides by combined chemical and microbial catalysis.

    PubMed

    Ge, Hai-Xia; Zhang, Jian; Qian, Kun; Yu, Bo-Yang; Chen, Xiao-Ping

    2016-10-01

    The present study was designed to construct the structurally diverse library of tetrahydroprotoberberines (THPBs) by combining the methods of chemical nonselective demethylation and microbial glycosylation. HPLC-MS/MS analyses tentatively identified 12 de-methylated and 9 glycosylated derivates of THPBs and 5 rarely oxidized glycosides of THPBs in the library. Through this effort, we achieved not only a variety of the THPBs and their glycosides but also tested the catalytic characteristics and capabilities of G. deliquescens NRRL 1086.

  15. Reflectance Infrared Spectroscopy on Operating Surface Acoustic Wave Chemical Sensors During Exposure to Gas-Phase Analytes

    SciTech Connect

    Hierlemann, A.; Hill, M.; Ricco, A.J.; Staton, A.W.; Thomas, R.C.

    1999-01-11

    We have developed instrumentation to enable the combination of surface acoustic wave (SAW) sensor measurements with direct, in-situ molecular spectroscopic measurements to understand the response of the SAW sensors with respect to the interfacial chemistry of surface-confined sensing films interacting with gas-phase analytes. Specifically, the instrumentation and software was developed to perform in-situ Fourier-transform infrared external-reflectance spectroscopy (FTIR-ERS) on operating SAW devices during dosing of their chemically modified surfaces with analytes. By probing the surface with IR spectroscopy during gas exposure, it is possible to understand in unprecedented detail the interaction processes between the sorptive SAW coatings and the gaseous analyte molecules. In this report, we provide details of this measurement system, and also demonstrate the utility of these combined measurements by characterizing the SAW and FTIR-ERS responses of organic thin-film sensor coatings interacting with gas-phase analytes.

  16. Meta-analytic evidence for a superordinate cognitive control network subserving diverse executive functions

    PubMed Central

    Laird, Angela R.; Ray, Kimberly L.; Dean, Y. Monica; Glahn, David C.; Carter, Cameron S.

    2013-01-01

    Classic cognitive theory conceptualizes executive functions as involving multiple specific domains, including initiation, inhibition, working memory, flexibility, planning, and vigilance. Lesion and neuroimaging experiments over the past two decades have suggested that both common and unique processes contribute to executive functions during higher cognition. It has been suggested that a superordinate fronto–cingulo–parietal network supporting cognitive control may also underlie a range of distinct executive functions. To test this hypothesis in the largest sample to date, we used quantitative meta-analytic methods to analyze 193 functional neuroimaging studies of 2,832 healthy individuals, ages 18–60, in which performance on executive function measures was contrasted with an active control condition. A common pattern of activation was observed in the prefrontal, dorsal anterior cingulate, and parietal cortices across executive function domains, supporting the idea that executive functions are supported by a superordinate cognitive control network. However, domain-specific analyses showed some variation in the recruitment of anterior prefrontal cortex, anterior and midcingulate regions, and unique subcortical regions such as the basal ganglia and cerebellum. These results are consistent with the existence of a superordinate cognitive control network in the brain, involving dorsolateral prefrontal, anterior cingulate, and parietal cortices, that supports a broad range of executive functions. PMID:22282036

  17. Modeling the binding affinity of structurally diverse industrial chemicals to carbon using the artificial intelligence approaches.

    PubMed

    Gupta, Shikha; Basant, Nikita; Rai, Premanjali; Singh, Kunwar P

    2015-11-01

    Binding affinity of chemical to carbon is an important characteristic as it finds vast industrial applications. Experimental determination of the adsorption capacity of diverse chemicals onto carbon is both time and resource intensive, and development of computational approaches has widely been advocated. In this study, artificial intelligence (AI)-based ten different qualitative and quantitative structure-property relationship (QSPR) models (MLPN, RBFN, PNN/GRNN, CCN, SVM, GEP, GMDH, SDT, DTF, DTB) were established for the prediction of the adsorption capacity of structurally diverse chemicals to activated carbon following the OECD guidelines. Structural diversity of the chemicals and nonlinear dependence in the data were evaluated using the Tanimoto similarity index and Brock-Dechert-Scheinkman statistics. The generalization and prediction abilities of the constructed models were established through rigorous internal and external validation procedures performed employing a wide series of statistical checks. In complete dataset, the qualitative models rendered classification accuracies between 97.04 and 99.93%, while the quantitative models yielded correlation (R(2)) values of 0.877-0.977 between the measured and the predicted endpoint values. The quantitative prediction accuracies for the higher molecular weight (MW) compounds (class 4) were relatively better than those for the low MW compounds. Both in the qualitative and quantitative models, the Polarizability was the most influential descriptor. Structural alerts responsible for the extreme adsorption behavior of the compounds were identified. Higher number of carbon and presence of higher halogens in a molecule rendered higher binding affinity. Proposed QSPR models performed well and outperformed the previous reports. A relatively better performance of the ensemble learning models (DTF, DTB) may be attributed to the strengths of the bagging and boosting algorithms which enhance the predictive accuracies. The

  18. Fading correlation and analytical performance evaluation of the space-diversity free-space optical communications system

    NASA Astrophysics Data System (ADS)

    Yang, G.; Khalighi, M. A.; Bourennane, S.; Ghassemlooy, Z.

    2014-03-01

    This paper investigates fading correlation in space-diversity free-space optical (FSO) communication systems and its effect on the link performance. We firstly evaluate the fading correlation in multiple-aperture FSO systems using wave-optics simulations. The influence of different system parameters including the link distance and aperture spacing is illustrated under realistic beam propagation conditions. In particular, we show that, at relatively large link distances where the scattering disk is much larger than the receiver aperture size, the fading correlation coefficient is almost independent of the apertures’ diameter and depends only on the apertures’ edge separation. To investigate the impact of fading correlation on the system’s performance, we propose an analytical approach to evaluate the performance of the space-diversity FSO system over a correlated Gamma-Gamma (ΓΓ) fading channel. Our approach is based on approximating the sum of arbitrarily correlated ΓΓ random variables by an α-μ distribution. To validate the accuracy of this method, we evaluate the average bit-error-rate (BER) performance for the case of a multiple-aperture FSO system and compare it with the BER results obtained via Monte Carlo simulations.

  19. Chemical and genetic diversity of high-seed-yield sorghum (Sorghum bicolor M.) germplasms.

    PubMed

    Ryu, J; Im, S B; Kwon, S J; Ahn, J W; Jeong, S W; Kang, S Y

    2016-09-02

    This study evaluated the chemical and genetic diversity of high-seed-yield sorghum germplasms from Korea, the United States, and South Africa. We identified significant differences in the chemical contents of whole plants at the heading stage in all cultivars, including differences in crude protein, fat, fiber, ash, neutral detergent fiber, acid detergent fiber, mineral, and fatty acid contents. Our results suggest that Banwoldang is the most appropriate cultivar for roughage because of its high protein yield. We identified significant differences in the tannin, flavonoid, amylose, mineral, crude fat, fatty acid, and 3-deoxyanthocyanin contents in the whole grain from all cultivars, but not in the mineral or crude fat contents. Tannin levels were generally low. IS645 contained the highest levels of flavonoids and linolenic acid compounds, and Moktak had the highest amylose and deoxyanthocyanidin content in the grain. To assess genetic diversity, we used 10 simple sequence repeat (SSR) primer sets to identify 38 alleles with 3-8 alleles per locus. Based on phylogenetic analysis of the SSR markers, the sorghum cultivars were divided into three major groups. Comparison of clusters based on chemical compositions with those based on SSRs showed that the groups formed by the three native Korean cultivars clustered similarly in molecular dendrograms. Association analysis was conducted for the 10 SSR marker; 48 chemical and growth traits were present for two marker traits (seed color and whole plant fatty acid content) with significant marker-trait associations. These markers could be used to select sorghum cultivars for breeding programs.

  20. Multispecies QSAR modeling for predicting the aquatic toxicity of diverse organic chemicals for regulatory toxicology.

    PubMed

    Singh, Kunwar P; Gupta, Shikha; Kumar, Anuj; Mohan, Dinesh

    2014-05-19

    The research aims to develop multispecies quantitative structure-activity relationships (QSARs) modeling tools capable of predicting the acute toxicity of diverse chemicals in various Organization for Economic Co-operation and Development (OECD) recommended test species of different trophic levels for regulatory toxicology. Accordingly, the ensemble learning (EL) approach based classification and regression QSAR models, such as decision treeboost (DTB) and decision tree forest (DTF) implementing stochastic gradient boosting and bagging algorithms were developed using the algae (P. subcapitata) experimental toxicity data for chemicals. The EL-QSAR models were successfully applied to predict toxicities of wide groups of chemicals in other test species including algae (S. obliguue), daphnia, fish, and bacteria. Structural diversity of the selected chemicals and those of the end-point toxicity data of five different test species were tested using the Tanimoto similarity index and Kruskal-Wallis (K-W) statistics. Predictive and generalization abilities of the constructed QSAR models were compared using statistical parameters. The developed QSAR models (DTB and DTF) yielded a considerably high classification accuracy in complete data of model building (algae) species (97.82%, 99.01%) and ranged between 92.50%-94.26% and 92.14%-94.12% in four test species, respectively, whereas regression QSAR models (DTB and DTF) rendered high correlation (R(2)) between the measured and model predicted toxicity end-point values and low mean-squared error in model building (algae) species (0.918, 0.15; 0.905, 0.21) and ranged between 0.575 and 0.672, 0.18-0.51 and 0.605-0.689 and 0.20-0.45 in four different test species. The developed QSAR models exhibited good predictive and generalization abilities in different test species of varied trophic levels and can be used for predicting the toxicities of new chemicals for screening and prioritization of chemicals for regulation.

  1. Predicting acute aquatic toxicity of structurally diverse chemicals in fish using artificial intelligence approaches.

    PubMed

    Singh, Kunwar P; Gupta, Shikha; Rai, Premanjali

    2013-09-01

    The research aims to develop global modeling tools capable of categorizing structurally diverse chemicals in various toxicity classes according to the EEC and European Community directives, and to predict their acute toxicity in fathead minnow using set of selected molecular descriptors. Accordingly, artificial intelligence approach based classification and regression models, such as probabilistic neural networks (PNN), generalized regression neural networks (GRNN), multilayer perceptron neural network (MLPN), radial basis function neural network (RBFN), support vector machines (SVM), gene expression programming (GEP), and decision tree (DT) were constructed using the experimental toxicity data. Diversity and non-linearity in the chemicals' data were tested using the Tanimoto similarity index and Brock-Dechert-Scheinkman statistics. Predictive and generalization abilities of various models constructed here were compared using several statistical parameters. PNN and GRNN models performed relatively better than MLPN, RBFN, SVM, GEP, and DT. Both in two and four category classifications, PNN yielded a considerably high accuracy of classification in training (95.85 percent and 90.07 percent) and validation data (91.30 percent and 86.96 percent), respectively. GRNN rendered a high correlation between the measured and model predicted -log LC50 values both for the training (0.929) and validation (0.910) data and low prediction errors (RMSE) of 0.52 and 0.49 for two sets. Efficiency of the selected PNN and GRNN models in predicting acute toxicity of new chemicals was adequately validated using external datasets of different fish species (fathead minnow, bluegill, trout, and guppy). The PNN and GRNN models showed good predictive and generalization abilities and can be used as tools for predicting toxicities of structurally diverse chemical compounds.

  2. Nature of the binding interaction for 50 structurally diverse chemicals with rat estrogen receptors.

    PubMed

    Laws, Susan C; Yavanhxay, S; Cooper, Ralph L; Eldridge, J Charles

    2006-11-01

    This study was conducted to characterize the estrogen receptor (ER)-binding affinities of 50 chemicals selected from among the high production volume chemicals under the U.S. EPA's (U.S. Environmental Protection Agency's) Toxic Substances Control Act inventory. The chemicals were evaluated using the rat uterine cytosolic (RUC) ER-competitive binding assay, with secondary analysis using Lineweaver-Burk plots and slope replots to confirm true competitive inhibition and to determine an experimental K(i). Data from these ER-competitive binding assays represent the types of competitive binding curves that can be obtained when screening chemicals with broad structural diversity. True competitive inhibition was observed in 17 of 50 chemicals. Binding affinities were much lower than that of estradiol (E(2)) with K(i) concentrations ranging from 0.6 to 373 microM as compared with that of E(2) (0.77 nM). Other chemicals that appeared to displace radiolabeled E(2) binding to ER were, in fact, found not to be competitive inhibitors in the secondary K(i) experiments. These seven chemicals likely altered the stability of the assay by changing the buffer pH, denaturing ER, or disrupting the ER-binding kinetics. Thus, several conditions that may confound interpretation of RUC ER-binding assay data are illustrated. For another group of eight chemicals, neither an IC(50) nor K(i) could be determined due to solubility constraints. These chemicals exhibited slight (20-40%) inhibition at concentrations of 10-100 microM, suggesting that they could be competitors at very high concentrations, yet K(i) experiments were not possible as the limit of chemical solubility in the aqueous assay buffer was well above the IC(50). An additional 18 of the 50 chemicals were classified as nonbinders because in concentrations up to 100 microM they produced essentially no displacement of radiolabeled E(2). These results show that although the ER-competitive binding assay is a valuable tool for screening

  3. Analytical methods for the quantification of bisphenol A, alkylphenols, phthalate esters, and perfluoronated chemicals in biological samples.

    PubMed

    Nakazawa, Hiroyuki; Iwasaki, Yusuke; Ito, Rie

    2014-01-01

    Our modern society has created a large number of chemicals that are used for the production of everyday commodities including toys, food packaging, cosmetic products, and building materials. We enjoy a comfortable and convenient lifestyle with access to these items. In addition, in specialized areas, such as experimental science and various medical fields, laboratory equipment and devices that are manufactured using a wide range of chemical substances are also extensively employed. The association between human exposure to trace hazardous chemicals and an increased incidence of endocrine disease has been recognized. However, the evaluation of human exposure to such endocrine disrupting chemicals is therefore imperative, and the determination of exposure levels requires the analysis of human biological materials, such as blood and urine. To obtain as much information as possible from limited sample sizes, highly sensitive and reliable analytical methods are also required for exposure assessments. The present review focuses on effective analytical methods for the quantification of bisphenol A (BPA), alkylphenols (APs), phthalate esters (PEs), and perfluoronated chemicals (PFCs), which are chemicals used in the production of everyday commodities. Using data obtained from liquid chromatography/mass spectrometry (LC/MS) and LC/MS/MS analyses, assessments of the risks to humans were also presented based on the estimated levels of exposure to PFCs.

  4. Chemical and Genetic Diversity of Nodularia spumigena from the Baltic Sea

    PubMed Central

    Mazur-Marzec, Hanna; Bertos-Fortis, Mireia; Toruńska-Sitarz, Anna; Fidor, Anna; Legrand, Catherine

    2016-01-01

    Nodularia spumigena is a toxic, filamentous cyanobacterium occurring in brackish waters worldwide, yet forms extensive recurrent blooms in the Baltic Sea. N. spumigena produces several classes of non-ribosomal peptides (NRPs) that are active against several key metabolic enzymes. Previously, strains from geographically distant regions showed distinct NRP metabolic profiles. In this work, conspecific diversity in N. spumigena was studied using chemical and genetic approaches. NRP profiles were determined in 25 N. spumigena strains isolated in different years and from different locations in the Baltic Sea using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Genetic diversity was assessed by targeting the phycocyanin intergenic spacer and flanking regions (cpcBA-IGS). Overall, 14 spumigins, 5 aeruginosins, 2 pseudaeruginosins, 2 nodularins, 36 anabaenopeptins, and one new cyanopeptolin-like peptide were identified among the strains. Seven anabaenopeptins were new structures; one cyanopeptolin-like peptide was discovered in N. spumigena for the first time. Based on NRP profiles and cpcBA-IGS sequences, the strains were grouped into two main clusters without apparent influence of year and location, indicating persistent presence of these two subpopulations in the Baltic Sea. This study is a major step in using chemical profiling to explore conspecific diversity with a higher resolution than with a sole genetic approach. PMID:27834904

  5. The antimicrobial potential of ionic liquids: A source of chemical diversity for infection and biofilm control.

    PubMed

    Pendleton, Jack Norman; Gilmore, Brendan F

    2015-08-01

    Although described almost a century ago, interest in ionic liquids has flourished in the last two decades, with significant advances in the understanding of their chemical, physical and biological property sets driving their widespread application across multiple and diverse research areas. Significant progress has been made through the contributions of numerous research groups detailing novel libraries of ionic liquids, often 'task-specific' designer solvents for application in areas as diverse as separation technology, catalysis and bioremediation. Basic antimicrobial screening has often been included as a surrogate indication of the environmental impact of these compounds widely regarded as 'green' solvents. Obviating the biological properties, specifically toxicity, of these compounds has obstructed their potential application as sophisticated designer biocides. A recent tangent in ionic liquids research now aims to harness tuneable biological properties of these compounds in the design of novel potent antimicrobials, recognising their unparalleled flexibility for chemical diversity in a severely depleted antimicrobial arsenal. This review concentrates primarily on the antimicrobial potential of ionic liquids and aims to consolidate contemporary microbiological background information, assessment protocols and future considerations necessary to advance the field in light of the urgent need for antimicrobial innovation.

  6. Importance of Genetic Diversity Assessment in Crop Plants and Its Recent Advances: An Overview of Its Analytical Perspectives

    PubMed Central

    Govindaraj, M.; Vetriventhan, M.; Srinivasan, M.

    2015-01-01

    The importance of plant genetic diversity (PGD) is now being recognized as a specific area since exploding population with urbanization and decreasing cultivable lands are the critical factors contributing to food insecurity in developing world. Agricultural scientists realized that PGD can be captured and stored in the form of plant genetic resources (PGR) such as gene bank, DNA library, and so forth, in the biorepository which preserve genetic material for long period. However, conserved PGR must be utilized for crop improvement in order to meet future global challenges in relation to food and nutritional security. This paper comprehensively reviews four important areas; (i) the significance of plant genetic diversity (PGD) and PGR especially on agriculturally important crops (mostly field crops); (ii) risk associated with narrowing the genetic base of current commercial cultivars and climate change; (iii) analysis of existing PGD analytical methods in pregenomic and genomic era; and (iv) modern tools available for PGD analysis in postgenomic era. This discussion benefits the plant scientist community in order to use the new methods and technology for better and rapid assessment, for utilization of germplasm from gene banks to their applied breeding programs. With the advent of new biotechnological techniques, this process of genetic manipulation is now being accelerated and carried out with more precision (neglecting environmental effects) and fast-track manner than the classical breeding techniques. It is also to note that gene banks look into several issues in order to improve levels of germplasm distribution and its utilization, duplication of plant identity, and access to database, for prebreeding activities. Since plant breeding research and cultivar development are integral components of improving food production, therefore, availability of and access to diverse genetic sources will ensure that the global food production network becomes more sustainable

  7. Importance of genetic diversity assessment in crop plants and its recent advances: an overview of its analytical perspectives.

    PubMed

    Govindaraj, M; Vetriventhan, M; Srinivasan, M

    2015-01-01

    The importance of plant genetic diversity (PGD) is now being recognized as a specific area since exploding population with urbanization and decreasing cultivable lands are the critical factors contributing to food insecurity in developing world. Agricultural scientists realized that PGD can be captured and stored in the form of plant genetic resources (PGR) such as gene bank, DNA library, and so forth, in the biorepository which preserve genetic material for long period. However, conserved PGR must be utilized for crop improvement in order to meet future global challenges in relation to food and nutritional security. This paper comprehensively reviews four important areas; (i) the significance of plant genetic diversity (PGD) and PGR especially on agriculturally important crops (mostly field crops); (ii) risk associated with narrowing the genetic base of current commercial cultivars and climate change; (iii) analysis of existing PGD analytical methods in pregenomic and genomic era; and (iv) modern tools available for PGD analysis in postgenomic era. This discussion benefits the plant scientist community in order to use the new methods and technology for better and rapid assessment, for utilization of germplasm from gene banks to their applied breeding programs. With the advent of new biotechnological techniques, this process of genetic manipulation is now being accelerated and carried out with more precision (neglecting environmental effects) and fast-track manner than the classical breeding techniques. It is also to note that gene banks look into several issues in order to improve levels of germplasm distribution and its utilization, duplication of plant identity, and access to database, for prebreeding activities. Since plant breeding research and cultivar development are integral components of improving food production, therefore, availability of and access to diverse genetic sources will ensure that the global food production network becomes more sustainable

  8. Bioturbo similarity searching: combining chemical and biological similarity to discover structurally diverse bioactive molecules.

    PubMed

    Wassermann, Anne Mai; Lounkine, Eugen; Glick, Meir

    2013-03-25

    Virtual screening using bioactivity profiles has become an integral part of currently applied hit finding methods in pharmaceutical industry. However, a significant drawback of this approach is that it is only applicable to compounds that have been biologically tested in the past and have sufficient activity annotations for meaningful profile comparisons. Although bioactivity data generated in pharmaceutical institutions are growing on an unprecedented scale, the number of biologically annotated compounds still covers only a minuscule fraction of chemical space. For a newly synthesized compound or an isolated natural product to be biologically characterized across multiple assays, it may take a considerable amount of time. Consequently, this chemical matter will not be included in virtual screening campaigns based on bioactivity profiles. To overcome this problem, we herein introduce bioturbo similarity searching that uses chemical similarity to map molecules without biological annotations into bioactivity space and then searches for biologically similar compounds in this reference system. In benchmark calculations on primary screening data, we demonstrate that our approach generally achieves higher hit rates and identifies structurally more diverse compounds than approaches using chemical information only. Furthermore, our method is able to discover hits with novel modes of inhibition that traditional 2D and 3D similarity approaches are unlikely to discover. Test calculations on a set of natural products reveal the practical utility of the approach for identifying novel and synthetically more accessible chemical matter.

  9. [60]Fullerene-peptides: bio-nano conjugates with structural and chemical diversity.

    PubMed

    Barron, Andrew R

    2016-01-01

    [60]Fullerene-peptides represent a simple yet chemically diverse example of a bio-nano conjugate. The C60 moiety provides the following attributes to the conjugate: (a) precise three-dimensional architecture, (b) a large hydrophobic mass and (c) unique electronic properties. Conversely, the peptide component provides: (a) structural diversity depending on the overall length and amino acids composition, (b) charge flexibility and (c) secondary structure and recognition. Recent advances in the synthetic strategy for [60]fullerene-peptide synthesis from both pre-formed peptides and using solid phase peptide synthesis (SPPS) are described. The effects of the hydrophobic C60 on the secondary structure of the peptide depend on the sequence of the latter, but in general the relative stability of particular structures is greatly enhanced. The ability of the [60]fullerene substituent to dramatically modify both cellular uptake and transdermal transport is discussed as is the effects on cell viability and antimicrobial activity.

  10. The Influence of Chemical Chaperones on Enzymatic Activity under Thermal and Chemical Stresses: Common Features and Variation among Diverse Chemical Families

    PubMed Central

    Feibish, Nir; Sharon, Noa; Schnaider, Lee; Shmul, Guy; Amir, Yaniv; Buzhansky, Ludmila; Gazit, Ehud

    2014-01-01

    Molecular and chemical chaperones are key components of the two main mechanisms that ensure structural stability and activity under environmental stresses. Yet, chemical chaperones are often regarded only as osmolytes and their role beyond osmotic regulation is not fully understood. Here, we systematically studied a large group of chemical chaperones, representatives of diverse chemical families, for their protective influence under either thermal or chemical stresses. Consistent with previous studies, we observed that in spite of the structural similarity between sugars and sugar alcohols, they have an apparent difference in their protective potential. Our results support the notion that the protective activity is mediated by the solvent and the presence of water is essential. In the current work we revealed that i) polyols and sugars have a completely different profile of protective activity toward trifluoroethanol and thermal stress; ii) minor changes in solvent composition that do not affect enzyme activity, yet have a great effect on the ability of osmolytes to act as protectants and iii) increasing the number of active groups of carbohydrates makes them better protectants while increasing the number of active groups of methylamines does not, as revealed by attempts to synthesize de novo designed methylamines with multiple functional groups. PMID:24520396

  11. The influence of chemical chaperones on enzymatic activity under thermal and chemical stresses: common features and variation among diverse chemical families.

    PubMed

    Levy-Sakin, Michal; Berger, Or; Feibish, Nir; Sharon, Noa; Schnaider, Lee; Shmul, Guy; Amir, Yaniv; Buzhansky, Ludmila; Gazit, Ehud

    2014-01-01

    Molecular and chemical chaperones are key components of the two main mechanisms that ensure structural stability and activity under environmental stresses. Yet, chemical chaperones are often regarded only as osmolytes and their role beyond osmotic regulation is not fully understood. Here, we systematically studied a large group of chemical chaperones, representatives of diverse chemical families, for their protective influence under either thermal or chemical stresses. Consistent with previous studies, we observed that in spite of the structural similarity between sugars and sugar alcohols, they have an apparent difference in their protective potential. Our results support the notion that the protective activity is mediated by the solvent and the presence of water is essential. In the current work we revealed that i) polyols and sugars have a completely different profile of protective activity toward trifluoroethanol and thermal stress; ii) minor changes in solvent composition that do not affect enzyme activity, yet have a great effect on the ability of osmolytes to act as protectants and iii) increasing the number of active groups of carbohydrates makes them better protectants while increasing the number of active groups of methylamines does not, as revealed by attempts to synthesize de novo designed methylamines with multiple functional groups.

  12. Standardization of chemical analytical techniques for pyrolysis bio-oil: history, challenges, and current status of methods

    DOE PAGES

    Ferrell, Jack R.; Olarte, Mariefel V.; Christensen, Earl D.; ...

    2016-07-05

    Here, we discuss the standardization of analytical techniques for pyrolysis bio-oils, including the current status of methods, and our opinions on future directions. First, the history of past standardization efforts is summarized, and both successful and unsuccessful validation of analytical techniques highlighted. The majority of analytical standardization studies to-date has tested only physical characterization techniques. In this paper, we present results from an international round robin on the validation of chemical characterization techniques for bio-oils. Techniques tested included acid number, carbonyl titrations using two different methods (one at room temperature and one at 80 °C), 31P NMR for determination ofmore » hydroxyl groups, and a quantitative gas chromatography–mass spectrometry (GC-MS) method. Both carbonyl titration and acid number methods have yielded acceptable inter-laboratory variabilities. 31P NMR produced acceptable results for aliphatic and phenolic hydroxyl groups, but not for carboxylic hydroxyl groups. As shown in previous round robins, GC-MS results were more variable. Reliable chemical characterization of bio-oils will enable upgrading research and allow for detailed comparisons of bio-oils produced at different facilities. Reliable analytics are also needed to enable an emerging bioenergy industry, as processing facilities often have different analytical needs and capabilities than research facilities. We feel that correlations in reliable characterizations of bio-oils will help strike a balance between research and industry, and will ultimately help to -determine metrics for bio-oil quality. Lastly, the standardization of additional analytical methods is needed, particularly for upgraded bio-oils.« less

  13. Standardization of chemical analytical techniques for pyrolysis bio-oil: history, challenges, and current status of methods

    SciTech Connect

    Ferrell, Jack R.; Olarte, Mariefel V.; Christensen, Earl D.; Padmaperuma, Asanga B.; Connatser, Raynella M.; Stankovikj, Filip; Meier, Dietrich; Paasikallio, Ville

    2016-07-05

    Here, we discuss the standardization of analytical techniques for pyrolysis bio-oils, including the current status of methods, and our opinions on future directions. First, the history of past standardization efforts is summarized, and both successful and unsuccessful validation of analytical techniques highlighted. The majority of analytical standardization studies to-date has tested only physical characterization techniques. In this paper, we present results from an international round robin on the validation of chemical characterization techniques for bio-oils. Techniques tested included acid number, carbonyl titrations using two different methods (one at room temperature and one at 80 °C), 31P NMR for determination of hydroxyl groups, and a quantitative gas chromatography–mass spectrometry (GC-MS) method. Both carbonyl titration and acid number methods have yielded acceptable inter-laboratory variabilities. 31P NMR produced acceptable results for aliphatic and phenolic hydroxyl groups, but not for carboxylic hydroxyl groups. As shown in previous round robins, GC-MS results were more variable. Reliable chemical characterization of bio-oils will enable upgrading research and allow for detailed comparisons of bio-oils produced at different facilities. Reliable analytics are also needed to enable an emerging bioenergy industry, as processing facilities often have different analytical needs and capabilities than research facilities. We feel that correlations in reliable characterizations of bio-oils will help strike a balance between research and industry, and will ultimately help to -determine metrics for bio-oil quality. Lastly, the standardization of additional analytical methods is needed, particularly for upgraded bio-oils.

  14. Bioluminescence in the Ocean: Origins of Biological, Chemical, and Ecological Diversity

    NASA Astrophysics Data System (ADS)

    Widder, E. A.

    2010-05-01

    From bacteria to fish, a remarkable variety of marine life depends on bioluminescence (the chemical generation of light) for finding food, attracting mates, and evading predators. Disparate biochemical systems and diverse phylogenetic distribution patterns of light-emitting organisms highlight the ecological benefits of bioluminescence, with biochemical and genetic analyses providing new insights into the mechanisms of its evolution. The origins and functions of some bioluminescent systems, however, remain obscure. Here, I review recent advances in understanding bioluminescence in the ocean and highlight future research efforts that will unite molecular details with ecological and evolutionary relationships.

  15. Chemical diversity of microbial volatiles and their potential for plant growth and productivity

    PubMed Central

    Kanchiswamy, Chidananda Nagamangala; Malnoy, Mickael; Maffei, Massimo E.

    2015-01-01

    Microbial volatile organic compounds (MVOCs) are produced by a wide array of microorganisms ranging from bacteria to fungi. A growing body of evidence indicates that MVOCs are ecofriendly and can be exploited as a cost-effective sustainable strategy for use in agricultural practice as agents that enhance plant growth, productivity, and disease resistance. As naturally occurring chemicals, MVOCs have potential as possible alternatives to harmful pesticides, fungicides, and bactericides as well as genetic modification. Recent studies performed under open field conditions demonstrate that efficiently adopting MVOCs may contribute to sustainable crop protection and production. We review here the chemical diversity of MVOCs by describing microbial–plants and microbial–microbial interactions. Furthermore, we discuss MVOCs role in inducing phenotypic plant responses and their potential physiological effects on crops. Finally, we analyze potential and actual limitations for MVOC use and deployment in field conditions as a sustainable strategy for improving productivity and reducing pesticide use. PMID:25821453

  16. Chemical diversity of microbial volatiles and their potential for plant growth and productivity.

    PubMed

    Kanchiswamy, Chidananda Nagamangala; Malnoy, Mickael; Maffei, Massimo E

    2015-01-01

    Microbial volatile organic compounds (MVOCs) are produced by a wide array of microorganisms ranging from bacteria to fungi. A growing body of evidence indicates that MVOCs are ecofriendly and can be exploited as a cost-effective sustainable strategy for use in agricultural practice as agents that enhance plant growth, productivity, and disease resistance. As naturally occurring chemicals, MVOCs have potential as possible alternatives to harmful pesticides, fungicides, and bactericides as well as genetic modification. Recent studies performed under open field conditions demonstrate that efficiently adopting MVOCs may contribute to sustainable crop protection and production. We review here the chemical diversity of MVOCs by describing microbial-plants and microbial-microbial interactions. Furthermore, we discuss MVOCs role in inducing phenotypic plant responses and their potential physiological effects on crops. Finally, we analyze potential and actual limitations for MVOC use and deployment in field conditions as a sustainable strategy for improving productivity and reducing pesticide use.

  17. Microbial community diversity and physical-chemical features of the Southwestern Atlantic Ocean.

    PubMed

    Alves Junior, Nelson; Meirelles, Pedro Milet; de Oliveira Santos, Eidy; Dutilh, Bas; Silva, Genivaldo G Z; Paranhos, Rodolfo; Cabral, Anderson S; Rezende, Carlos; Iida, Tetsuya; de Moura, Rodrigo L; Kruger, Ricardo Henrique; Pereira, Renato C; Valle, Rogério; Sawabe, Tomoo; Thompson, Cristiane; Thompson, Fabiano

    2015-03-01

    Microbial oceanography studies have demonstrated the central role of microbes in functioning and nutrient cycling of the global ocean. Most of these former studies including at Southwestern Atlantic Ocean (SAO) focused on surface seawater and benthic organisms (e.g., coral reefs and sponges). This is the first metagenomic study of the SAO. The SAO harbors a great microbial diversity and marine life (e.g., coral reefs and rhodolith beds). The aim of this study was to characterize the microbial community diversity of the SAO along the depth continuum and different water masses by means of metagenomic, physical-chemical and biological analyses. The microbial community abundance and diversity appear to be strongly influenced by the temperature, dissolved organic carbon, and depth, and three groups were defined [1. surface waters; 2. sub-superficial chlorophyll maximum (SCM) (48-82 m) and 3. deep waters (236-1,200 m)] according to the microbial composition. The microbial communities of deep water masses [South Atlantic Central water, Antarctic Intermediate water and Upper Circumpolar Deep water] are highly similar. Of the 421,418 predicted genes for SAO metagenomes, 36.7 % had no homologous hits against 17,451,486 sequences from the North Atlantic, South Atlantic, North Pacific, South Pacific and Indian Oceans. From these unique genes from the SAO, only 6.64 % had hits against the NCBI non-redundant protein database. SAO microbial communities share genes with the global ocean in at least 70 cellular functions; however, more than a third of predicted SAO genes represent a unique gene pool in global ocean. This study was the first attempt to characterize the taxonomic and functional community diversity of different water masses at SAO and compare it with the microbial community diversity of the global ocean, and SAO had a significant portion of endemic gene diversity. Microbial communities of deep water masses (236-1,200 m) are highly similar, suggesting that these water

  18. Consequences of plant-chemical diversity for domestic goat food preference in Mediterranean forests

    NASA Astrophysics Data System (ADS)

    Baraza, Elena; Hódar, José A.; Zamora, Regino

    2009-01-01

    The domestic goat, a major herbivore in the Mediterranean basin, has demonstrated a strong ability to adapt its feeding behaviour to the chemical characteristics of food, selecting plants according to their nutritive quality. In this study, we determine some chemical characteristics related to plant nutritional quality and its variability among and within five tree species, these being the main components of the mountain forests of SE Spain, with the aim of determining their influence on food selection by this generalist herbivore. We analyse nitrogen, total phenols, condensed tannins and fibre concentration as an indicator of the nutritive value of the different trees. To determine the preference by the domestic goat, we performed two types of feeding-choice assays, where goats had to select between different species or between branches of the same species but from trees of different nutritional quality. The analysis of the plant nutritional quality showed significant differences in the chemical characteristics between species, and a high variability within species. However, when faced with different tree species, the domestic goat selected some of them but showed striking individual differences between goats. When selecting between trees of the same species, the goats showed no differential selection. This limited effect of chemical plant characteristics, together with the variability in foraging behaviour, resulted in a widespread consumption of diverse plant species, which can potentially modulate the effect of the goat on vegetation composition, and open the way for the conservation of traditional livestock grazing on natural protected areas.

  19. Co-Cultivation—A Powerful Emerging Tool for Enhancing the Chemical Diversity of Microorganisms

    PubMed Central

    Marmann, Andreas; Aly, Amal H.; Lin, Wenhan; Wang, Bingui; Proksch, Peter

    2014-01-01

    Marine-derived bacteria and fungi are promising sources of novel bioactive compounds that are important for drug discovery programs. However, as encountered in terrestrial microorganisms there is a high rate of redundancy that results in the frequent re-discovery of known compounds. Apparently only a part of the biosynthetic genes that are harbored by fungi and bacteria are transcribed under routine laboratory conditions which involve cultivation of axenic microbial strains. Many biosynthetic genes remain silent and are not expressed in vitro thereby seriously limiting the chemical diversity of microbial compounds that can be obtained through fermentation. In contrast to this, co-cultivation (also called mixed fermentation) of two or more different microorganisms tries to mimic the ecological situation where microorganisms always co-exist within complex microbial communities. The competition or antagonism experienced during co-cultivation is shown to lead to a significantly enhanced production of constitutively present compounds and/or to an accumulation of cryptic compounds that are not detected in axenic cultures of the producing strain. This review highlights the power of co-cultivation for increasing the chemical diversity of bacteria and fungi drawing on published studies from the marine and from the terrestrial habitat alike. PMID:24549204

  20. Comparison of physico-chemical parameters and zooplankton diversity in two perennial ponds at Aligarh, India.

    PubMed

    Parveen, Saltanat; Abdel Mola, Hesham R

    2013-07-01

    Investigations were carried out on the diversity of zooplankton in relation to physico-chemical parameters of two perennial ponds (Chautal Pond and Medical Pond) of Aligarh, India. Thirty nine species of holoplankton were identified belonging to copepoda (2 species), rotifera (28 species), cladocera (6 species) and protozoa (3 species). Other forms; like as meroplankton (insects) and tychoplankton (nematodes and ostracodes) were also recorded. Higher values of physico-chemical parameters and low zooplankton diversity were recorded in the Chautal Pond, whereas low values of physico-chemical parameters and high diversity were recorded in the Medical Pond. Ostracods considered to be the most dominant group in Medical Pond (32.16% of the total zooplankton) while Cladocerans are considered to be the most dominant group in Chautal Pond (38.83% of the total zooplankton). Rotifera contributed more in Medical Pond (16.42%) as compared to Chautal Pond (15.81%). Five species of Brachionus was recorded during study. Out of five, four Brachionus species were recorded in Chautal Pond while only two species were recorded in Medical pond. This indicates that Chautal Pond is more eutrophic than Medical pond. In addition, higher carbon dioxide values (37-105 mg l(-1)), low dissolved oxygen (0.7-3.3 mg I(-1)) and higher electrical conductivity values (1069-1691 mg l(-1)) were also indicative of eutrophic nature of Chautal Pond. Present study also revealed that total zooplankton species, species richness and diversity indices (Evenness, Shannon-Winner and Simpson) were comparatively higher in Medical pond. The rotifer species Philodina roseola (146 Org. l(-1)) and Monstyla closterocerca (109 Org. l(-1)) was dominated in Medical Pond while the rotifers Brachionus urceolaris (512 Org. l(-1)) and the cladocern species Ceriodaphnia cornuta (1540 Org. l(-1)) dominated in Chautal Pond during post-monsoon season. This might be due to the effect of rain water which played an important role in

  1. Enhancing the diversity of a corporate database using chemical database clustering and analysis

    NASA Astrophysics Data System (ADS)

    Shemetulskis, Norah E.; Dunbar, James B., Jr.; Dunbar, Bonnie W.; Moreland, David W.; Humblet, Christine

    1995-10-01

    The contribution that the Chemical Abstracts structural database (CAST-3D) and the Maybridge database (MAY) would make to diversifying the structural information and property space spanned by our corporate database (CBI) is assessed. A subset of the CAST-3D database has been selected to augment the structural diversity of various electronic databases used in computer-assisted drug design projects. The analysis of the MAY database directly offers the potential to expand the CBI compound library, but also provides a source for structural diversity in a format suitable for computer-assisted database searching and molecular design. The analysis performed is twofold. First, a nonhierarchical clustering technique available in the Daylight clustering package is applied to evaluate the structural differences between databases. The comparison is then extended to analyze various structure-derived property spaces calculated from molecular descriptors such as the logarithm of the octanol-water partition coefficient (CLOGP), the molar refractivity (CMR) and the electronic dipole moment (CDM). The diversity contribution of each database to these property spaces is quantified in relation to our corporate database.

  2. QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP MODELS FOR PREDICTION OF ESTROGEN RECEPTOR BINDING AFFINITY OF STRUCTURALLY DIVERSE CHEMICALS

    EPA Science Inventory

    The demonstrated ability of a variety of structurally diverse chemicals to bind to the estrogen receptor has raised the concern that chemicals in the environment may be causing adverse effects through interference with nuclear receptor pathways. Many structure-activity relationsh...

  3. Effect of widespread agricultural chemical use on butterfly diversity across Turkish provinces.

    PubMed

    Pekin, Burak K

    2013-12-01

    Although agricultural intensification is thought to pose a significant threat to species, little is known about its role in driving biodiversity loss at regional scales. I assessed the effects of a major component of agricultural intensification, agricultural chemical use, and land-cover and climatic variables on butterfly diversity across 81 provinces in Turkey, where agriculture is practiced extensively but with varying degrees of intensity. I determined butterfly species presence in each province from data on known butterfly distributions and calculated agricultural chemical use as the proportion of agricultural households that use chemical fertilizers and pesticides. I used constrained correspondence analyses and regression-based multimodel inference to determine the effect of environmental variables on species composition and richness, respectively. The variation in butterfly species composition across the provinces was largely explained (78%) by the combination of agricultural chemical use, particularly pesticides, and climatic and land-cover variables. Although overall butterfly richness was primarily explained by climatic and land-cover variables, such as the area of natural vegetation cover, threatened butterfly richness and the relative number of threatened butterfly species decreased substantially as the proportion of agricultural households using pesticides increased. These findings suggest that widespread use of agricultural chemicals, or other components of agricultural intensification that may be collinear with pesticide use, pose an imminent threat to the biodiversity of Turkey. Accordingly, policies that mitigate agricultural intensification and promote low-input farming practices are crucial for protecting threatened species from extinction in rapidly industrializing nations such as Turkey. Efectos del Uso Extensivo de Agroquímicos sobre la Diversidad de Mariposas en Provincias Turcas.

  4. Analytical and Characterization Studies of Organic Chemicals, Drugs, and Drug Formulation

    DTIC Science & Technology

    2011-11-21

    of the bulk drugs, drug products, to determine their stability under defined conditions, to prepare formulations of bulk drugs for biological...testing, and to coordinate ongoing stability studies on an artesunate dosage form with a subcontractor. 15. SUBJECT TERMS Anti-Parasitic Drugs, Chemical...Defense Agents, Chemical Analyses, Stability Studies, Formulation Development 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18

  5. Combined physical and chemical nonequilibrium transport model: Analytical solution, moments, and application to colloids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transport of solutes and colloids in porous media is influenced by a variety of physical and chemical nonequilibrium processes. A combined physical–chemical nonequilibrium (PCNE) model was therefore used to describe general mass transport. The model partitions the pore space into “mobile” and “i...

  6. CTEPP-OH DATA ANALYTICAL RESULTS ORGANIZED BY CHEMICAL AND MEDIA

    EPA Science Inventory

    This data set contains the field sample data by chemical and matrix for CTEPP-OH. The data is organized at the sample, chemical level.

    The Children’s Total Exposure to Persistent Pesticides and Other Persistent Pollutant (CTEPP) study was one of the largest aggregate exposure ...

  7. [Microbial metabolites that inhibit sterol biosynthesis, their chemical diversity and characteristics of mode of action].

    PubMed

    Trenin, A S

    2013-01-01

    Inhibitors of sterol biosynthesis (ISB) are widespread in nature and characterized by appreciable diversity both in their chemical structure and mode of action. Many of these inhibitors express noticeable biological activity and approved themselves in development of various pharmaceuticals. In this review there is a detailed description of biologically active microbial metabolites with revealed chemical structure that have ability to inhibit sterol biosynthesis. Inhibitors of mevalonate pathway in fungous and mammalian cells, exhibiting hypolipidemic or antifungal activity, as well as inhibitors of alternative non-mevalonate (pyruvate gliceraldehyde phosphate) isoprenoid pathway, which are promising in the development of affective antimicrobial or antiparasitic drugs, are under consideration in this review. Chemical formulas of the main natural inhibitors and their semi-synthetic derivatives are represented. Mechanism of their action at cellular and biochemical level is discussed. Special attention is given to inhibitors of 3-hydroxy-3-methylglutaryl Coenzyme A (HMG-CoA) reductase (group of lovastatin) and inhibitors of acyl-CoA-cholesterol-acyl transferase (ACAT) that possess hypolipidemic activity and could be affective in the treatment of atherosclerosis. In case of inhibitors of late stages of sterol biosynthesis (after squalene formation) special attention is paid to compounds possessing evident antifungal and antitumoral activity. Explanation of mechanism of anticancer and antiviral action of microbial ISB, as well as the description of their ability to induce apoptosis is given.

  8. Synthetic biology to access and expand nature’s chemical diversity

    PubMed Central

    Smanski, Michael J.; Zhou, Hui; Claesen, Jan; Shen, Ben; Fischbach, Michael; Voigt, Christopher A.

    2016-01-01

    Bacterial genomes encode the biosynthetic potential to produce hundreds of thousands of complex molecules with diverse applications, from medicine to agriculture and materials. Economically accessing the potential encoded within sequenced genomes promises to reinvigorate waning drug discovery pipelines and provide novel routes to intricate chemicals. This is a tremendous undertaking, as the pathways often comprise dozens of genes spanning as much as 100+ kiliobases of DNA, are controlled by complex regulatory networks, and the most interesting molecules are made by non-model organisms. Advances in synthetic biology address these issues, including DNA construction technologies, genetic parts for precision expression control, synthetic regulatory circuits, computer aided design, and multiplexed genome engineering. Collectively, these technologies are moving towards an era when chemicals can be accessed en mass based on sequence information alone. This will enable the harnessing of metagenomic data and massive strain banks for high-throughput molecular discovery and, ultimately, the ability to forward design pathways to complex chemicals not found in nature. PMID:26876034

  9. Flavonoids: chemical properties and analytical methodologies of identification and quantitation in foods and plants.

    PubMed

    Corradini, Eleonora; Foglia, Patrizia; Giansanti, Piero; Gubbiotti, Riccardo; Samperi, Roberto; Lagana, Aldo

    2011-03-01

    Flavonoids have been recognised as one of the largest and most widespread groups of plant secondary metabolites, with marked antioxidant properties. The general name flavonoid refers to a class of more than 6500 molecules based upon a 15-carbon skeleton. In this paper a general overview of flavonoids, their classification, structures and analytical methods for their determination is presented.

  10. The radial dependence of pebble accretion rates: A source of diversity in planetary systems. I. Analytical formulation

    NASA Astrophysics Data System (ADS)

    Ida, S.; Guillot, T.; Morbidelli, A.

    2016-06-01

    Context. The classical planetesimal accretion scenario for the formation of planets has recently evolved with the idea that pebbles, centimeter- to meter-sized icy grains migrating in protoplanetary disks, can control planetesimal and/or planetary growth. Aims: We investigate how pebble accretion depends on disk properties and affects the formation of planetary systems. Methods: We construct analytical models of pebble accretion onto planetary embryos that consistently account for the mass and orbital evolution of the pebble flow and reflect disk structure. Results: We derive simple formulas for pebble accretion rates in the so-called settling regime for planetary embryos that are more than 100 km in size. For relatively smaller embryos or in outer disk regions, the accretion mode is three-dimensional (3D), meaning that the thickness of the pebble flow must be taken into account, and resulting in an accretion rate that is independent of the embryo mass. For larger embryos or in inner regions, the accretion is in a two-dimensional (2D) mode, i.e., the pebble disk may be considered infinitely thin. We show that the radial dependence of the pebble accretion rate is different (even the sign of the power-law exponent changes) for different disk conditions such as the disk heating source (viscous heating or stellar irradiation), drag law (Stokes or Epstein, and weak or strong coupling), and in the 2D or 3D accretion modes. We also discuss the effect of the sublimation and destruction of icy pebbles inside the snow line. Conclusions: Pebble accretion easily produces a large diversity of planetary systems. In other words, to infer the results of planet formation through pebble accretion correctly, detailed prescriptions of disk evolution and pebble growth, sublimation, destruction and migration are required.

  11. Chemical Diversity in the Ultra-faint Dwarf Galaxy Tucana II

    NASA Astrophysics Data System (ADS)

    Ji, Alexander P.; Frebel, Anna; Ezzeddine, Rana; Casey, Andrew R.

    2016-11-01

    We present the first detailed chemical abundance study of the ultra-faint dwarf galaxy Tucana II, based on high-resolution Magellan/MIKE spectra of four red giant stars. The metallicities of these stars range from [Fe/H] = -3.2 to -2.6, and all stars are low in neutron-capture abundances ([Sr/Fe] and [Ba/Fe] < -1). However, a number of anomalous chemical signatures are present. One star is relatively metal-rich ([Fe/H] = -2.6) and shows [Na, α, Sc/Fe] < 0, suggesting an extended star formation history with contributions from AGB stars and SNe Ia. Two stars with [Fe/H] < -3 are mildly carbon-enhanced ([C/Fe] ˜ 0.7) and may be consistent with enrichment by faint supernovae, if such supernovae can produce neutron-capture elements. A fourth star with [Fe/H] = -3 is carbon-normal, and exhibits distinct light element abundance ratios from the carbon-enhanced stars. This carbon-normal star implies that at least two distinct nucleosynthesis sources, both possibly associated with Population III stars, contributed to the early chemical enrichment of this galaxy. Despite its very low luminosity, Tucana II shows a diversity of chemical signatures that preclude it from being a simple “one-shot” first galaxy yet still provide a window into star and galaxy formation in the early universe. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  12. Analytical methods for chemical and sensory characterization of scent-markings in large wild mammals: a review.

    PubMed

    Soso, Simone B; Koziel, Jacek A; Johnson, Anna; Lee, Young Jin; Fairbanks, W Sue

    2014-03-05

    In conjoining the disciplines of "ethology" and "chemistry" the field of "Ethochemistry" has been instituted. Ethochemistry is an effective tool in conservation efforts of endangered species and the understanding of behavioral patterns across all species. Chemical constituents of scent-markings have an important, yet poorly understood function in territoriality, reproduction, dominance, and impact on evolutionary biology, especially in large mammals. Particular attention has recently been focused on scent-marking analysis of great cats (Kalahari leopards (Panthera pardus), puma (Puma concolor) snow leopard (Panthera uncia), African lions (Panthera leo), cheetahs (Acinonyx jubatus), and tigers (Panthera tigris)) for the purpose of conservation. Sensory analyses of scent-markings could address knowledge gaps in ethochemistry. The objective of this review is to summarize the current state-of-the art of both the chemical and sensory analyses of scent-markings in wild mammals. Specific focus is placed on sampling and sample preparation, chemical analysis, sensory analysis, and simultaneous chemical and sensory analyses. Constituents of exocrine and endocrine secretions have been most commonly studied with chromatography-based analytical separations. Odor analysis of scent-markings provides an insight into the animal's sensory perception. A limited number of articles have been published in the area of sensory characterization of scent marks. Simultaneous chemical and sensory analyses with chromatography-olfactometry hyphenation could potentially aid conservation efforts by linking perceived odor, compounds responsible for odor, and resulting behavior.

  13. Analytical Methods for Chemical and Sensory Characterization of Scent-Markings in Large Wild Mammals: A Review

    PubMed Central

    Soso, Simone B.; Koziel, Jacek A.; Johnson, Anna; Lee, Young Jin; Fairbanks, W. Sue

    2014-01-01

    In conjoining the disciplines of “ethology” and “chemistry” the field of “Ethochemistry” has been instituted. Ethochemistry is an effective tool in conservation efforts of endangered species and the understanding of behavioral patterns across all species. Chemical constituents of scent-markings have an important, yet poorly understood function in territoriality, reproduction, dominance, and impact on evolutionary biology, especially in large mammals. Particular attention has recently been focused on scent-marking analysis of great cats (Kalahari leopards (Panthera pardus), puma (Puma concolor) snow leopard (Panthera uncia), African lions (Panthera leo), cheetahs (Acinonyx jubatus), and tigers (Panthera tigris)) for the purpose of conservation. Sensory analyses of scent-markings could address knowledge gaps in ethochemistry. The objective of this review is to summarize the current state-of-the art of both the chemical and sensory analyses of scent-markings in wild mammals. Specific focus is placed on sampling and sample preparation, chemical analysis, sensory analysis, and simultaneous chemical and sensory analyses. Constituents of exocrine and endocrine secretions have been most commonly studied with chromatography-based analytical separations. Odor analysis of scent-markings provides an insight into the animal's sensory perception. A limited number of articles have been published in the area of sensory characterization of scent marks. Simultaneous chemical and sensory analyses with chromatography-olfactometry hyphenation could potentially aid conservation efforts by linking perceived odor, compounds responsible for odor, and resulting behavior. PMID:24603639

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

    PubMed

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

    2013-08-22

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

  15. Fluid Diversion and Sweep Improvement with Chemical Gels in Oil Recovery Processes

    SciTech Connect

    Seright, R.S.; Martin, F.D.

    1991-11-01

    This report describes progress made during the second year of the three-year project, Fluid diversion and Sweep Improvement with Chemical Gels in Oil Recovery Processes.'' The objectives of this project are to identify the mechanisms by which gel treatments divert fluids in reservoirs and to establish where and how gel treatments are best applied. Several different types of gelants are being examined. This research is directed at gel applications in water injection wells, in production wells, and in high-pressure gasfloods. The work examines how the flow properties of gels and gelling agents are influenced by permeability, lithology, and wettability. Other goals include determining the proper placement of gelants, the stability of in-place gels, and the types of gels required for the various oil recovery processes and for different scales of reservoir heterogeneity. 93 refs., 39 figs., 43 tabs.

  16. Chemical Diversity and Biological Properties of Secondary Metabolites from Sea Hares of Aplysia Genus

    PubMed Central

    Pereira, Renato B.; Andrade, Paula B.; Valentão, Patrícia

    2016-01-01

    The marine environment is an important source of structurally-diverse and biologically-active secondary metabolites. During the last two decades, thousands of compounds were discovered in marine organisms, several of them having inspired the development of new classes of therapeutic agents. Marine mollusks constitute a successful phyla in the discovery of new marine natural products (MNPs). Over a 50-year period from 1963, 116 genera of mollusks contributed innumerous compounds, Aplysia being the most studied genus by MNP chemists. This genus includes 36 valid species and should be distinguished from all mollusks as it yielded numerous new natural products. Aplysia sea hares are herbivorous mollusks, which have been proven to be a rich source of secondary metabolites, mostly of dietary origin. The majority of secondary metabolites isolated from sea hares of the genus Aplysia are halogenated terpenes; however, these animals are also a source of compounds from other chemical classes, such as macrolides, sterols and alkaloids, often exhibiting cytotoxic, antibacterial, antifungal, antiviral and/or antifeedant activities. This review focuses on the diverse structural classes of secondary metabolites found in Aplysia spp., including several compounds with pronounced biological properties. PMID:26907303

  17. Soils of Sub-Antarctic tundras: diversity and basic chemical characteristics

    NASA Astrophysics Data System (ADS)

    Abakumov, Evgeny; Vlasov, Dmitry; Mukhametova, Nadezhda

    2014-05-01

    Antarctic peninsula is known as specific part of Antarctica, which is characterizes by humid and relatively warm climate of so-called sub Antarctic (maritime) zone. Annual precipitation and long above zero period provides the possibility of sustainable tundra's ecosystem formation. Therefore, the soil diversity of these tundra landscapes is maximal in the whole Antarctic. Moreover, the thickness of parent material debris's is also highest and achieves a 1 or 2 meters as highest. The presence of higher vascular plants Deshampsia antarctica which is considered as one of the main edificators provides the development of humus accumulation in upper solum. Penguins activity provides an intensive soil fertilization and development of plant communities with increased density. All these factors leads to formation of specific and quite diverse soil cover in sub Antarctic tundra's. These ecosystems are presented by following permafrost affected soils: Leptosols, Lithoosols, Crysols, Gleysols, Peats and Ornhitosols. Also the post Ornhitosols are widely spreaded in subantarcic ecosystems, they forms on the penguin rockeries during the plant succession development, leaching of nutrients and organic matter mineralization. "Amphibious" soils are specific for seasonal lakes, which evaporates in the end if Australian summer. These soils have specific features of bio sediments and soils as well. Soil chemical characteristic as well as organic matter features discussed in comparison with Antacrtic continental soil in presentation.

  18. MmpL3 Inhibitors: Diverse Chemical Scaffolds Inhibit the Same Target.

    PubMed

    Poce, Giovanna; Consalvi, Sara; Biava, Mariangela

    2016-01-01

    MmpL3 belongs to the Resistance, Nodulation and Division (RND) superfamily whose role in mycobacteria is the formation of the outer membrane. Indeed, it has been shown that MmpL3 is associated with the export of mycolic acids in the form of trehalose monomycolates (TMM) to the periplasmic space or the outer membrane. In the last few years several whole cell-based screenings of compound libraries brought by a number of diverse chemical scaffolds active against M. tuberculosis (Mtb) that surprisingly share MmpL3 as target. The diverse identified pharmacophores owe important differences among each other, in fact while some of them display inhibitory activity against pathogens that are devoid of mycolic acids and are active against non-replicating Mtb bacilli, some others specifically target mycobacteria and do not kill non-replicating bacilli. The scope of this review is to provide the recent advances in MmpL3 inhibitor discovery with a special focus on structure activity relationship (SAR) studies in order to provide information that could help in developing novel membrane-active anti- TB agents. Moreover, this review will provide the most recent insights into the modes of action of the MmpL3 inhibitors.

  19. Chemical Diversity and Biological Properties of Secondary Metabolites from Sea Hares of Aplysia Genus.

    PubMed

    Pereira, Renato B; Andrade, Paula B; Valentão, Patrícia

    2016-02-19

    The marine environment is an important source of structurally-diverse and biologically-active secondary metabolites. During the last two decades, thousands of compounds were discovered in marine organisms, several of them having inspired the development of new classes of therapeutic agents. Marine mollusks constitute a successful phyla in the discovery of new marine natural products (MNPs). Over a 50-year period from 1963, 116 genera of mollusks contributed innumerous compounds, Aplysia being the most studied genus by MNP chemists. This genus includes 36 valid species and should be distinguished from all mollusks as it yielded numerous new natural products. Aplysia sea hares are herbivorous mollusks, which have been proven to be a rich source of secondary metabolites, mostly of dietary origin. The majority of secondary metabolites isolated from sea hares of the genus Aplysia are halogenated terpenes; however, these animals are also a source of compounds from other chemical classes, such as macrolides, sterols and alkaloids, often exhibiting cytotoxic, antibacterial, antifungal, antiviral and/or antifeedant activities. This review focuses on the diverse structural classes of secondary metabolites found in Aplysia spp., including several compounds with pronounced biological properties.

  20. Indole Alkaloids of the Stigonematales (Cyanophyta): Chemical Diversity, Biosynthesis and Biological Activity

    PubMed Central

    Walton, Katherine; Berry, John P.

    2016-01-01

    The cyanobacteria are well recognized as producers of a wide array of bioactive metabolites including toxins, and potential drug candidates. However, a limited number of taxa are generally considered with respect to both of these aspects. That said, the order Stigonematales, although largely overlooked in this regard, has become increasingly recognized as a source of bioactive metabolites relevant to both human and environmental health. In particular, the hapalindoles and related indole alkaloids (i.e., ambiguines, fischerindoles, welwitindolinones) from the order, represent a diverse, and phylogenetically characteristic, class of secondary metabolites with biological activity suggestive of potential as both environmental toxins, and promising drug discovery leads. The present review gives an overview of the chemical diversity of biologically active metabolites from the Stigonematales—and particularly the so-called hapalindole-type alkaloids—including their biosynthetic origins, and their pharmacologically and toxicologically relevant bioactivities. Taken together, the current evidence suggests that these alkaloids, and the associated cyanobacterial taxa from the order, warrant future consideration as both potentially harmful (i.e., “toxic”) algae, and as promising leads for drug discovery. PMID:27058546

  1. Plant P450s as versatile drivers for evolution of species-specific chemical diversity

    PubMed Central

    Hamberger, Björn; Bak, Søren

    2013-01-01

    The irreversible nature of reactions catalysed by P450s makes these enzymes landmarks in the evolution of plant metabolic pathways. Founding members of P450 families are often associated with general (i.e. primary) metabolic pathways, restricted to single copy or very few representatives, indicative of purifying selection. Recruitment of those and subsequent blooms into multi-member gene families generates genetic raw material for functional diversification, which is an inherent characteristic of specialized (i.e. secondary) metabolism. However, a growing number of highly specialized P450s from not only the CYP71 clan indicate substantial contribution of convergent and divergent evolution to the observed general and specialized metabolite diversity. We will discuss examples of how the genetic and functional diversification of plant P450s drives chemical diversity in light of plant evolution. Even though it is difficult to predict the function or substrate of a P450 based on sequence similarity, grouping with a family or subfamily in phylogenetic trees can indicate association with metabolism of particular classes of compounds. Examples will be given that focus on multi-member gene families of P450s involved in the metabolic routes of four classes of specialized metabolites: cyanogenic glucosides, glucosinolates, mono- to triterpenoids and phenylpropanoids. PMID:23297350

  2. The Impact of Chemical Abrasion on Trace Element Analysis of Zircon by In Situ Micro-Analytical Techniques

    NASA Astrophysics Data System (ADS)

    Romanoski, A.; Coint, N.; Cottle, J. M.; Hetherington, C. J.; Barnes, C. G.

    2011-12-01

    Introduction of the chemical abrasion technique has significantly increased the precision and accuracy of ID-TIMS U-Pb dating of zircon. The chemical abrasion technique, coupled with thermal annealing, removes inclusions and metamict domains from zircon reducing the impact of Pb-loss leading to more concordant analyses.In this study, zircon from the Red Bluff Granitic Suite (TX) (ID-TIMS age 1120 ± 35 Ma) has been thermally annealed and chemically abraded prior to SHRIMP-RG and LA-MC-ICP-MS analysis.Chemically abraded zircon gives a date of 1109 ± 22 Ma with an average of 3% discordancy. This compares with dates of 1137 ± 48 Ma with an average of 39% discordancy for non-abraded zircon from the same sample. The dates overlap within uncertainty, but the age from chemically abraded zircon has a lower population uncertainty. Other petrographic and analytical observations of the chemically abraded zircon include brighter CL intensity, lower REE abundances, more consistent (smaller scatter) negative Eu/Eu* anomalies, less scatter in the chondrite-normalized LREE values, and a slightly less-steep chondrite normalized HREE slope. The data show that thermal annealing and chemical abrasion of zircon prior to analysis by in situ ion-beam or laser ablation techniques may result in better accuracy and greater concordance in U-Pb analysis of zircon. However, while improving the quality of some components of the trace element dataset (e.g. Eu anomalies) the process may prejudice the interpretation of zircon trace element data (e.g. HREECN slopes).

  3. Analytic projection from plane-wave and PAW wavefunctions and application to chemical-bonding analysis in solids.

    PubMed

    Maintz, Stefan; Deringer, Volker L; Tchougréeff, Andrei L; Dronskowski, Richard

    2013-11-05

    Quantum-chemical computations of solids benefit enormously from numerically efficient plane-wave (PW) basis sets, and together with the projector augmented-wave (PAW) method, the latter have risen to one of the predominant standards in computational solid-state sciences. Despite their advantages, plane waves lack local information, which makes the interpretation of local densities-of-states (DOS) difficult and precludes the direct use of atom-resolved chemical bonding indicators such as the crystal orbital overlap population (COOP) and the crystal orbital Hamilton population (COHP) techniques. Recently, a number of methods have been proposed to overcome this fundamental issue, built around the concept of basis-set projection onto a local auxiliary basis. In this work, we propose a novel computational technique toward this goal by transferring the PW/PAW wavefunctions to a properly chosen local basis using analytically derived expressions. In particular, we describe a general approach to project both PW and PAW eigenstates onto given custom orbitals, which we then exemplify at the hand of contracted multiple-ζ Slater-type orbitals. The validity of the method presented here is illustrated by applications to chemical textbook examples-diamond, gallium arsenide, the transition-metal titanium-as well as nanoscale allotropes of carbon: a nanotube and the C60 fullerene. Remarkably, the analytical approach not only recovers the total and projected electronic DOS with a high degree of confidence, but it also yields a realistic chemical-bonding picture in the framework of the projected COHP method.

  4. Metabolomic Approaches to Explore Chemical Diversity of Human Breast-Milk, Formula Milk and Bovine Milk

    PubMed Central

    Qian, Linxi; Zhao, Aihua; Zhang, Yinan; Chen, Tianlu; Zeisel, Steven H.; Jia, Wei; Cai, Wei

    2016-01-01

    Although many studies have been conducted on the components present in human breast milk (HM), research on the differences of chemical metabolites between HM, bovine milk (BM) and formula milk (FM) is limited. This study was to explore the chemical diversity of HM, BM and FM by metabolomic approaches. GC-TOFMS and UPLC-QTOFMS were applied to investigate the metabolic compositions in 30 HM samples, 20 FM samples and 20 BM samples. Metabolite profiling identified that most of the non-esterified fatty acids, which reflected the hydrolysis of triglycerides, were much more abundant in HM than those in FM and BM, except for palmitic acid and stearic acid. The levels of tricarboxylic acid (TCA) intermediates were much higher in FM and BM than those in HM. Each type of milk also showed its unique composition of free amino acids and free carbohydrates. In conclusion, higher levels of non-esterified saturated fatty acids with aliphatic tails <16 carbons, monounsaturated fatty acids and polyunsaturated fatty acids and lower levels of TCA intermediates are characteristic of HM, as compared with FM and BM. The content of non-esterified fatty acids may reflect the hydrolysis of triglycerides in different milk types. PMID:27999311

  5. Metabolomic Approaches to Explore Chemical Diversity of Human Breast-Milk, Formula Milk and Bovine Milk.

    PubMed

    Qian, Linxi; Zhao, Aihua; Zhang, Yinan; Chen, Tianlu; Zeisel, Steven H; Jia, Wei; Cai, Wei

    2016-12-17

    Although many studies have been conducted on the components present in human breast milk (HM), research on the differences of chemical metabolites between HM, bovine milk (BM) and formula milk (FM) is limited. This study was to explore the chemical diversity of HM, BM and FM by metabolomic approaches. GC-TOFMS and UPLC-QTOFMS were applied to investigate the metabolic compositions in 30 HM samples, 20 FM samples and 20 BM samples. Metabolite profiling identified that most of the non-esterified fatty acids, which reflected the hydrolysis of triglycerides, were much more abundant in HM than those in FM and BM, except for palmitic acid and stearic acid. The levels of tricarboxylic acid (TCA) intermediates were much higher in FM and BM than those in HM. Each type of milk also showed its unique composition of free amino acids and free carbohydrates. In conclusion, higher levels of non-esterified saturated fatty acids with aliphatic tails <16 carbons, monounsaturated fatty acids and polyunsaturated fatty acids and lower levels of TCA intermediates are characteristic of HM, as compared with FM and BM. The content of non-esterified fatty acids may reflect the hydrolysis of triglycerides in different milk types.

  6. Chemical Diversity and Antimicrobial Activity of Salvia multicaulis Vahl Essential Oils.

    PubMed

    Fahed, Layal; Stien, Didier; Ouaini, Naïm; Eparvier, Véronique; El Beyrouthy, Marc

    2016-05-01

    The chemical compositions and antimicrobial activities of the essential oils (EOs) of aerial parts of Salvia multicaulis Vahl, collected during the same week from two different Lebanese regions, were investigated. The EOs were obtained by hydrodistillation using a Clevenger-type apparatus and characterized by GC and GC/MS analyses. The minimum inhibitory concentrations of these EOs were determined against one Gram-negative and two Gram-positive bacteria, one yeast, and five dermatophytes using the broth microdilution technique. One EO was notably active against Staphylococcus aureus, methicillin-resistant S. aureus, and all of the Trichophyton species tested. Nerolidol was found to be the major compound in the active oil; nerolidol was also absent from the inactive oil. This study demonstrated that nerolidol shows antimicrobial activity and therefore significantly contributes to the antimicrobial potential of the oil. The chemical diversity of worldwide S. multicaulis EOs was analyzed, revealing that the EOs of this study belong to two different chemotypes found in the literature. The nerolidol chemotype appears to be restricted to Lebanon, and it can be used as antimicrobial agent against external bacterial and fungal infections.

  7. Modelling a flows in supply chain with analytical models: Case of a chemical industry

    NASA Astrophysics Data System (ADS)

    Benhida, Khalid; Azougagh, Yassine; Elfezazi, Said

    2016-02-01

    This study is interested on the modelling of the logistics flows in a supply chain composed on a production sites and a logistics platform. The contribution of this research is to develop an analytical model (integrated linear programming model), based on a case study of a real company operating in the phosphate field, considering a various constraints in this supply chain to resolve the planning problems for a better decision-making. The objectives of this model is to determine and define the optimal quantities of different products to route, to and from the various entities in the supply chain studied.

  8. Self-Aspirated Atmospheric Pressure Chemical Ionization Source for Direct Sampling of Analytes on Surfaces and in Liquid Solutions

    SciTech Connect

    Asano, Keiji G; Ford, Michael J; Tomkins, Bruce A; Van Berkel, Gary J

    2005-01-01

    A self-aspirating heated nebulizer probe is described and demonstrated for use in the direct analysis of analytes on surfaces and in liquid samples by atmospheric pressure chemical ionization (APCI) mass spectrometry. Functionality and performance of the probe as a self-aspirating APCI source is demonstrated using reserpine and progesterone as test compounds. The utility of the probe to sample analytes directly from surfaces was demonstrated first by scanning development lanes of a reversed-phase thin-layer chromatography plate in which a three-component dye mixture, viz., Fat Red 7B, Solvent Green 3, and Solvent Blue 35, was spotted and the components were separated. Development lanes were scanned by the sampling probe operated under computer control (x, y plane) while full-scan mass spectra were recorded using a quadrupole ion trap mass spectrometer. In addition, the ability to sample the surface of pharmaceutical tablets (viz., Extra Strength Tylenol(reg. sign) and Evista(reg. sign) tablets) and to detect the active ingredients (acetaminophen and raloxifene, respectively) selectively was demonstrated using tandem mass spectrometry (MS/MS). Finally, the capability to sample analyte solutions from the wells of a 384-well microtiter plate and to perform quantitative analyses using MS/MS detection was illustrated with cotinine standards spiked with cotinine-d{sub 3} as an internal standard.

  9. Intraspecific chemical diversity among neighbouring plants correlates positively with plant size and herbivore load but negatively with herbivore damage.

    PubMed

    Bustos-Segura, Carlos; Poelman, Erik H; Reichelt, Michael; Gershenzon, Jonathan; Gols, Rieta

    2017-01-01

    Intraspecific plant diversity can modify the properties of associated arthropod communities and plant fitness. However, it is not well understood which plant traits determine these ecological effects. We explored the effect of intraspecific chemical diversity among neighbouring plants on the associated invertebrate community and plant traits. In a common garden experiment, intraspecific diversity among neighbouring plants was manipulated using three plant populations of wild cabbage that differ in foliar glucosinolates. Plants were larger, harboured more herbivores, but were less damaged when plant diversity was increased. Glucosinolate concentration differentially correlated with generalist and specialist herbivore abundance. Glucosinolate composition correlated with plant damage, while in polycultures, variation in glucosinolate concentrations among neighbouring plants correlated positively with herbivore diversity and negatively with plant damage levels. The results suggest that intraspecific variation in secondary chemistry among neighbouring plants is important in determining the structure of the associated insect community and positively affects plant performance.

  10. A Cluster Analytic Study of Clinical Orientations among Chemical Dependency Counselors.

    ERIC Educational Resources Information Center

    Thombs, Dennis L.; Osborn, Cynthia J.

    2001-01-01

    Three distinct clinical orientations were identified in a sample of chemical dependency counselors (N=406). Based on cluster analysis, the largest group, identified and labeled as "uniform counselors," endorsed a simple, moral-disease model with little interest in psychosocial interventions. (Contains 50 references and 4 tables.) (GCP)

  11. Analytical methods for the assessment of endocrine disrupting chemical exposure during human fetal and lactation stages: a review.

    PubMed

    Jiménez-Díaz, I; Vela-Soria, F; Rodríguez-Gómez, R; Zafra-Gómez, A; Ballesteros, O; Navalón, A

    2015-09-10

    In the present work, a review of the analytical methods developed in the last 15 years for the determination of endocrine disrupting chemicals (EDCs) in human samples related with children, including placenta, cord blood, amniotic fluid, maternal blood, maternal urine and breast milk, is proposed. Children are highly vulnerable to toxic chemicals in the environment. Among these environmental contaminants to which children are at risk of exposure are EDCs -substances able to alter the normal hormone function of wildlife and humans-. The work focuses mainly on sample preparation and instrumental techniques used for the detection and quantification of the analytes. The sample preparation techniques include, not only liquid-liquid extraction (LLE) and solid-phase extraction (SPE), but also modern microextraction techniques such as extraction with molecular imprinted polymers (MIPs), stir-bar sorptive extraction (SBSE), hollow-fiber liquid-phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME), matrix solid phase dispersion (MSPD) or ultrasound-assisted extraction (UAE), which are becoming alternatives in the analysis of human samples. Most studies focus on minimizing the number of steps and using the lowest solvent amounts in the sample treatment. The usual instrumental techniques employed include liquid chromatography (LC), gas chromatography (GC) mainly coupled to tandem mass spectrometry. Multiresidue methods are being developed for the determination of several families of EDCs with one extraction step and limited sample preparation.

  12. Ion suppression and enhancement effects of co-eluting analytes in multi-analyte approaches: systematic investigation using ultra-high-performance liquid chromatography/mass spectrometry with atmospheric-pressure chemical ionization or electrospray ionization.

    PubMed

    Remane, Daniela; Meyer, Markus R; Wissenbach, Dirk K; Maurer, Hans H

    2010-11-15

    In multi-analyte procedures, sufficient separation is important to avoid interferences, particularly when using liquid chromatography/mass spectrometry (LC/MS) because of possible ion suppression or enhancement. However, even using ultra-high-performance LC, baseline separation is not always possible. For development and validation of an LC/MS/MS approach for quantification of 140 antidepressants, benzodiazepines, neuroleptics, beta-blockers, oral antidiabetics, and analytes measured in the context of brain death diagnosis in plasma, the extent of ion suppression or enhancement of co-eluting analytes within and between the drug classes was investigated using atmospheric-pressure chemical ionization (APCI) or electrospray ionization (ESI). Within the drug classes, five analytes showed ion enhancement of over 25% and six analytes ion suppression of over 25% using APCI and 16 analytes ion suppression of over 25% using ESI. Between the drug classes, two analytes showed ion suppression of over 25% using APCI. Using ESI, one analyte showed ion enhancement of over 25% and five analytes ion suppression of over 25%. These effects may influence the drug quantification using calibrators made in presence of overlapping and thus interfering analytes. Ion suppression/enhancement effects induced by co-eluting drugs of different classes present in the patient sample may also lead to false measurements using class-specific calibrators made in absence of overlapping and thus interfering analytes. In conclusion, ion suppression and enhancement tests are essential during method development and validation in LC/MS/MS multi-analyte procedures, with special regards to co-eluting analytes.

  13. Model Analytical Development for Physical, Chemical, and Biological Characterization of Momordica charantia Vegetable Drug

    PubMed Central

    Guimarães, Geovani Pereira; Santos, Ravely Lucena; Júnior, Fernando José de Lima Ramos; da Silva, Karla Monik Alves; de Souza, Fabio Santos

    2016-01-01

    Momordica charantia is a species cultivated throughout the world and widely used in folk medicine, and its medicinal benefits are well documented, especially its pharmacological properties, including antimicrobial activities. Analytical methods have been used to aid in the characterization of compounds derived from plant drug extracts and their products. This paper developed a methodological model to evaluate the integrity of the vegetable drug M. charantia in different particle sizes, using different analytical methods. M. charantia was collected in the semiarid region of Paraíba, Brazil. The herbal medicine raw material derived from the leaves and fruits in different particle sizes was analyzed using thermoanalytical techniques as thermogravimetry (TG) and differential thermal analysis (DTA), pyrolysis coupled to gas chromatography/mass spectrometry (PYR-GC/MS), and nuclear magnetic resonance (1H NMR), in addition to the determination of antimicrobial activity. The different particle surface area among the samples was differentiated by the techniques. DTA and TG were used for assessing thermal and kinetic parameters and PYR-GC/MS was used for degradation products chromatographic identification through the pyrograms. The infusions obtained from the fruit and leaves of Momordica charantia presented antimicrobial activity. PMID:27579215

  14. Model Analytical Development for Physical, Chemical, and Biological Characterization of Momordica charantia Vegetable Drug.

    PubMed

    Brandão, Deysiane Oliveira; Guimarães, Geovani Pereira; Santos, Ravely Lucena; Júnior, Fernando José de Lima Ramos; da Silva, Karla Monik Alves; de Souza, Fabio Santos; Macêdo, Rui Oliveira

    2016-01-01

    Momordica charantia is a species cultivated throughout the world and widely used in folk medicine, and its medicinal benefits are well documented, especially its pharmacological properties, including antimicrobial activities. Analytical methods have been used to aid in the characterization of compounds derived from plant drug extracts and their products. This paper developed a methodological model to evaluate the integrity of the vegetable drug M. charantia in different particle sizes, using different analytical methods. M. charantia was collected in the semiarid region of Paraíba, Brazil. The herbal medicine raw material derived from the leaves and fruits in different particle sizes was analyzed using thermoanalytical techniques as thermogravimetry (TG) and differential thermal analysis (DTA), pyrolysis coupled to gas chromatography/mass spectrometry (PYR-GC/MS), and nuclear magnetic resonance ((1)H NMR), in addition to the determination of antimicrobial activity. The different particle surface area among the samples was differentiated by the techniques. DTA and TG were used for assessing thermal and kinetic parameters and PYR-GC/MS was used for degradation products chromatographic identification through the pyrograms. The infusions obtained from the fruit and leaves of Momordica charantia presented antimicrobial activity.

  15. Sample handling in surface sensitive chemical and biological sensing: a practical review of basic fluidics and analyte transport.

    PubMed

    Orgovan, Norbert; Patko, Daniel; Hos, Csaba; Kurunczi, Sándor; Szabó, Bálint; Ramsden, Jeremy J; Horvath, Robert

    2014-09-01

    This paper gives an overview of the advantages and associated caveats of the most common sample handling methods in surface-sensitive chemical and biological sensing. We summarize the basic theoretical and practical considerations one faces when designing and assembling the fluidic part of the sensor devices. The influence of analyte size, the use of closed and flow-through cuvettes, the importance of flow rate, tubing length and diameter, bubble traps, pressure-driven pumping, cuvette dead volumes, and sample injection systems are all discussed. Typical application areas of particular arrangements are also highlighted, such as the monitoring of cellular adhesion, biomolecule adsorption-desorption and ligand-receptor affinity binding. Our work is a practical review in the sense that for every sample handling arrangement considered we present our own experimental data and critically review our experience with the given arrangement. In the experimental part we focus on sample handling in optical waveguide lightmode spectroscopy (OWLS) measurements, but the present study is equally applicable for other biosensing technologies in which an analyte in solution is captured at a surface and its presence is monitored. Explicit attention is given to features that are expected to play an increasingly decisive role in determining the reliability of (bio)chemical sensing measurements, such as analyte transport to the sensor surface; the distorting influence of dead volumes in the fluidic system; and the appropriate sample handling of cell suspensions (e.g. their quasi-simultaneous deposition). At the appropriate places, biological aspects closely related to fluidics (e.g. cellular mechanotransduction, competitive adsorption, blood flow in veins) are also discussed, particularly with regard to their models used in biosensing.

  16. Exact Analytic Solution of the Non-Markovian Chemical Reaction Process Via Time-Subordination

    NASA Astrophysics Data System (ADS)

    Benson, D. A.

    2015-12-01

    Perfectly-mixed reactions are Markovian, because the advance of the state depends only on the current state. Poor mixing (or the partner process of upscaling over heterogeneous concentrations) renders the process non-Markovian because of memory of the chemical structure. In other words, a particle takes some time to reach a suitable reaction site. The time depends on structure, and the structure changes over time. For purely diffusive transport, a calculation of the random time to reach the edges of ``islands'' allows a solution of the non-Markovian reaction rates that evolve (decrease) over time. This randomization of the active (operational) reaction time leads to non-Markovian reactions and an integro-differential governing equation of chemical evolution. Implications for more complex (advection/diffusion) environments are discussed.

  17. Recent advances in chemical functionalization of nanoparticles with biomolecules for analytical applications.

    PubMed

    Oh, Ju-Hwan; Park, Do Hyun; Joo, Jang Ho; Lee, Jae-Seung

    2015-11-01

    The recent synthetic development of a variety of nanoparticles has led to their widespread application in diagnostics and therapeutics. In particular, the controlled size and shape of nanoparticles precisely determine their unique chemical and physical properties, which is highly attractive for accurate analysis of given systems. In addition to efforts toward controlling the synthesis and properties of nanoparticles, the surface functionalization of nanoparticles with biomolecules has been intensively investigated since the mid-1990s. The complicated yet programmable properties of biomolecules have proved to substantially enhance and enrich the novel functions of nanoparticles to achieve "smart" nanoparticle materials. In this review, the advances in chemical functionalization of four types of representative nanoparticle with DNA and protein molecules in the past five years are critically reviewed, and their future trends are predicted.

  18. Field Chemical Emissions Monitoring (FCEM) generic sampling and analytical plan. Final report

    SciTech Connect

    Behrens, G.P.; Huyck, K.A.; Youngerman, E.G.

    1995-03-01

    This report outlines a comprehensive approach to FCEM test planning, including the overall format for presentation of a typical test plan and examples of the type of information that is important to include. It discusses the following key topics: sampling locations and process monitoring for air toxics; specific sampling procedures for detecting and measuring toxic substances such as trace metals, semivolatile and volatile compounds, aldehydes, and mercury; currently preferred sample preparation and analytical methods; quality assurance considerations for precision, accuracy, and completeness; and data reduction and reporting methods and format. The report contains numerous helpful tables and illustrations, references to other available material, a glossary, and an appendix on defining and reporting detection limits.

  19. Visual characterization and diversity quantification of chemical libraries: 2. Analysis and selection of size-independent, subspace-specific diversity indices.

    PubMed

    Colliandre, Lionel; Le Guilloux, Vincent; Bourg, Stephane; Morin-Allory, Luc

    2012-02-27

    High Throughput Screening (HTS) is a standard technique widely used to find hit compounds in drug discovery projects. The high costs associated with such experiments have highlighted the need to carefully design screening libraries in order to avoid wasting resources. Molecular diversity is an established concept that has been used to this end for many years. In this article, a new approach to quantify the molecular diversity of screening libraries is presented. The approach is based on the Delimited Reference Chemical Subspace (DRCS) methodology, a new method that can be used to delimit the densest subspace spanned by a reference library in a reduced 2D continuous space. A total of 22 diversity indices were implemented or adapted to this methodology, which is used here to remove outliers and obtain a relevant cell-based partition of the subspace. The behavior of these indices was assessed and compared in various extreme situations and with respect to a set of theoretical rules that a diversity function should satisfy when libraries of different sizes have to be compared. Some gold standard indices are found inappropriate in such a context, while none of the tested indices behave perfectly in all cases. Five DRCS-based indices accounting for different aspects of diversity were finally selected, and a simple framework is proposed to use them effectively. Various libraries have been profiled with respect to more specific subspaces, which further illustrate the interest of the method.

  20. [Analytical and on-site detection methods for chemical warfare agents].

    PubMed

    Seto, Yasuo

    2006-12-01

    Chemical warfare agents (CWAs) are fast acting and sometimes lethal, even at low levels, and can be classified into nerve gases, blister agents, choking agents, blood agents, vomit agents, tear gases, and incapacitating agents. As countermeasures against CWA terrorism, detection and identification are important. In crisis management, monitoring of CWAs in public places and security checks at territorial borders, big event venues, and executive facilities are performed for protection against terrorism. In consequence management, on-site detection by first responders and laboratory analysis after on-site sampling and transfer are performed for minimization of terrorism damage, leading to personal protection, initial investigation, and emergency lifesaving. In incident management, laboratory analysis is performed to provide evidence at court trials for the prevention of future crimes. Laboratory analysis consists of pretreatment of on-site and casualty samples and instrumental analysis using GC-MS. However, CWAs are easily degraded, and thus are difficult to detect. Instead, it is useful to detect their metabolites and degradation products using tert-butyldimethylsilyl derivatization GC-MS or direct LC-MS. Commercially available chemical detection equipment such as gas detection tubes and ion mobility spectrometers are used for on-site detection. We have evaluated the detection performance of such equipment and found that no equipment fulfills the required perfect performance of CWA detection sensitivity, accuracy, response time, return time, and operation. To overcome the drawbacks, we have adopted the monitoring tape method and counterflow introduction atmospheric pressure chemical ionization mass spectrometry and recommend the combination of commercial detection equipment and these new technologies for simultaneous, rapid detection of all CWAs.

  1. New analytical solutions for chemical evolution models: characterizing the population of star-forming and passive galaxies

    NASA Astrophysics Data System (ADS)

    Spitoni, E.; Vincenzo, F.; Matteucci, F.

    2017-02-01

    Context. Analytical models of chemical evolution, including inflow and outflow of gas, are important tools for studying how the metal content in galaxies evolves as a function of time. Aims: We present new analytical solutions for the evolution of the gas mass, total mass, and metallicity of a galactic system when a decaying exponential infall rate of gas and galactic winds are assumed. We apply our model to characterize a sample of local star-forming and passive galaxies from the Sloan Digital Sky Survey data, with the aim of reproducing their observed mass-metallicity relation. Methods: We derived how the two populations of star-forming and passive galaxies differ in their particular distribution of ages, formation timescales, infall masses, and mass loading factors. Results: We find that the local passive galaxies are, on average, older and assembled on shorter typical timescales than the local star-forming galaxies; on the other hand, the star-forming galaxies with higher masses generally show older ages and longer typical formation timescales compared than star-forming galaxies with lower masses. The local star-forming galaxies experience stronger galactic winds than the passive galaxy population. Exploring the effect of assuming different initial mass functions in our model, we show that to reproduce the observed mass-metallicity relation, stronger winds are requested if the initial mass function is top-heavy. Finally, our analytical models predict the assumed sample of local galaxies to lie on a tight surface in the 3D space defined by stellar metallicity, star formation rate, and stellar mass, in agreement with the well-known fundamental relation from adopting gas-phase metallicity. Conclusions: By using a new analytical model of chemical evolution, we characterize an ensemble of SDSS galaxies in terms of their infall timescales, infall masses, and mass loading factors. Local passive galaxies are, on average, older and assembled on shorter typical

  2. Acidification in the Adirondacks: Defining the Biota in trophic Levels of 30 Chemically Diverse Acid-Impacted Lakes

    EPA Science Inventory

    The Adirondack Mountains in New York State have a varied surficial geology and chemically diverse surface waters that are among the most impacted by acid deposition in the U.S. No single Adirondack investigation has been comprehensive in defining the effects of acidification on ...

  3. Canopy spectral and chemical diversity from lowland to tree line in the Western Amazon using CAO-VSWIR

    NASA Astrophysics Data System (ADS)

    Martin, R. E.; Asner, G. P.

    2012-12-01

    Canopy chemistry and spectroscopy offer insight into community assembly and ecosystem processes in high-diversity tropical forests. Results from one lowland site in the Peruvian Amazon suggests both an environmental and an evolutionary component of canopy trait development however, the degree to which larger environmental differences influence diversity in canopy traits and their respective spectroscopic signatures across remains poorly understood. The spectranomics approach explicitly connects phylogenetic, chemical and spectral patterns in tropical canopies providing the basis for analysis, while high-fidelity, airborne remote sensing measurements extend plot-level data to landscape-scale, achieving a comprehensive view of the region. In 2011, the Carnegie Airborne Observatory (CAO) was used to sample a large region of the Western Amazon Basin in southeastern Peru, extending from lowlands to tree line in the Andean mountains. The CAO Visible-Shortwave Imaging Spectrometer (VSWIR) collected 480-band high-fidelity imaging spectroscopy data of the forest canopy, while its high-resolution LiDAR captured information on canopy structure and the underlying terrain. The data were used to quantify relationships between environmental gradients and canopy chemical and spectral diversity. Results suggest strong environmental control with additional phylogenetic influence over canopy spectral and chemical properties, particularly those related to structure, defense and metabolic function. Data from CAO-VSWIR extends the large range in canopy chemical and spectral diversity related to environmental factors across the Western Amazon Basin.

  4. Chemical and process mineralogical characterizations of spent lithium-ion batteries: an approach by multi-analytical techniques.

    PubMed

    Zhang, Tao; He, Yaqun; Wang, Fangfang; Ge, Linhan; Zhu, Xiangnan; Li, Hong

    2014-06-01

    Mineral processing operation is a critical step in any recycling process to realize liberation, separation and concentration of the target parts. Developing effective recycling methods to recover all the valuable parts from spent lithium-ion batteries is in great necessity. The aim of this study is to carefully undertake chemical and process mineralogical characterizations of spent lithium-ion batteries by coupling several analytical techniques to provide basic information for the researches on effective mechanical crushing and separation methods in recycling process. The results show that the grade of Co, Cu and Al is fairly high in spent lithium ion batteries and up to 17.62 wt.%, 7.17 wt.% and 21.60 wt.%. Spent lithium-ion batteries have good selective crushing property, the crushed products could be divided into three parts, they are Al-enriched fraction (+2 mm), Cu and Al-enriched fraction (-2+0.25 mm) and Co and graphite-enriched fraction (-0.25 mm). The mineral phase and chemical state analysis reveal the electrode materials recovered from -0.25 mm size fraction keep the original crystal forms and chemical states in lithium-ion batteries, but the surface of the powders has been coated by a certain kind of hydrocarbon. Based on these results a flowsheet to recycle spent LiBs is proposed.

  5. Genetic Diversity and Structure of Populations of Annona crassiflora Mart. of Brazilian Savanna and Its Association with Chemical Variability.

    PubMed

    Egydio-Brandão, Anary Priscila Monteiro; Furlan, Claudia Maria; Dos Santos, Déborah Yara Alves Cursino

    2016-08-01

    Annona crassiflora Mart. is a native tree from Brazilian savanna. Isoquinoline alkaloids are characteristic of species of Annonaceae. This work aimed to assess the magnitude of genetic diversity among different populations of A. crassiflora using AFLP markers, and verify the existence of any correlation between the AFLP data and previous reported alkaloid composition. A. crassiflora from eight populations in the states of São Paulo, Goiás, Minas Gerais, and Distrito Federal were analyzed. The data suggest a low, moderate, and high level of genetic diversity from different populations of A. crassiflora. Concentration of alkaloids was significantly correlated with AFLP data, suggesting interaction between chemical and molecular markers in A. crassiflora. The data of association between the chemical and genetic differentiation of A. crassiflora may be useful to establish cultivation areas allowing the definition of strategies to preserve their genetic diversity with an interest in specific chemotypes for genetic improvement programs focused on sustainable utilization of this specie.

  6. Improving analytical methods for protein-protein interaction through implementation of chemically inducible dimerization

    PubMed Central

    Andersen, Tonni Grube; Nintemann, Sebastian J.; Marek, Magdalena; Halkier, Barbara A.; Schulz, Alexander; Burow, Meike

    2016-01-01

    When investigating interactions between two proteins with complementary reporter tags in yeast two-hybrid or split GFP assays, it remains troublesome to discriminate true- from false-negative results and challenging to compare the level of interaction across experiments. This leads to decreased sensitivity and renders analysis of weak or transient interactions difficult to perform. In this work, we describe the development of reporters that can be chemically induced to dimerize independently of the investigated interactions and thus alleviate these issues. We incorporated our reporters into the widely used split ubiquitin-, bimolecular fluorescence complementation (BiFC)- and Förster resonance energy transfer (FRET)- based methods and investigated different protein-protein interactions in yeast and plants. We demonstrate the functionality of this concept by the analysis of weakly interacting proteins from specialized metabolism in the model plant Arabidopsis thaliana. Our results illustrate that chemically induced dimerization can function as a built-in control for split-based systems that is easily implemented and allows for direct evaluation of functionality. PMID:27282591

  7. Analytical models of the impact of two-phase sorption on subsurface transport of volatile chemicals

    SciTech Connect

    Shoemaker, C.A.; Culver, T.B.; Lion, L.W.; Peterson, M.G. )

    1990-04-01

    Unsaturated zone models incorporating the impact of vapor-phase sorption on transport of volatile organic compounds are presented with closed from solutions for one-and two-dimensional cases. In addition to vapor-phase sorption the models incorporate liquid-phase sorption, liquid advection, gaseous diffusion, and volatilization into soil air spaces and to the atmosphere. The motivation for incorporation of vapor-phase sorption arises from recent experimental results by the authors indicating that vapor-phase sorption may be orders of magnitude higher than liquid-phase sorption under certain soil conditions. The sensitivity analysis suggests that there is considerable interaction among the physical and chemical processes involved in transport of volatile organic compounds. Pollutant concentrations are most affected by the Henry's law constant and gaseous diffusion; the speed of movement of the material depends most upon the pore water velocity and vapor-phase sorption. The incorporation of vapor-phase sorption can significantly reduce model predictions of the transport speed and amount of volatile chemical reaching the groundwater under dry soil conditions. This result is of considerable practical significance since models currently used for remediation and regulation do not include vapor-phase sorption.

  8. NMR chemical shift as analytical derivative of the Helmholtz free energy.

    PubMed

    Van den Heuvel, Willem; Soncini, Alessandro

    2013-02-07

    We present a theory for the temperature-dependent nuclear magnetic shielding tensor of molecules with arbitrary electronic structure. The theory is a generalization of Ramsey's theory for closed-shell molecules. The shielding tensor is defined as a second derivative of the Helmholtz free energy of the electron system in equilibrium with the applied magnetic field and the nuclear magnetic moments. This derivative is analytically evaluated and expressed as a sum over states formula. Special consideration is given to a system with an isolated degenerate ground state for which the size of the degeneracy and the composition of the wave functions are arbitrary. In this case, the paramagnetic part of the shielding tensor is expressed in terms of the g and A tensors of the electron paramagnetic resonance spin Hamiltonian of the degenerate state. As an illustration of the proposed theory, we provide an explicit formula for the paramagnetic shift of the central lanthanide ion in endofullerenes Ln@C(60), with Ln = Ce(3+), Nd(3+), Sm(3+), Dy(3+), Er(3+), and Yb(3+), where the ground state can be a strongly spin-orbit coupled icosahedral sextet for which the paramagnetic shift cannot be described by previous theories.

  9. Using additive modelling to quantify the effect of chemicals on phytoplankton diversity and biomass.

    PubMed

    Viaene, K P J; De Laender, F; Van den Brink, P J; Janssen, C R

    2013-04-01

    Environmental authorities require the protection of biodiversity and other ecosystem properties such as biomass production. However, the endpoints listed in available ecotoxicological datasets generally do not contain these two ecosystem descriptors. Inferring the effects of chemicals on such descriptors from micro- or mesocosm experiments is often hampered by inherent differences in the initial biodiversity levels between experimental units or by delayed community responses. Here we introduce additive modelling to establish the effects of a chronic application of the herbicide linuron on 10 biodiversity indices and phytoplankton biomass in microcosms. We found that communities with a low (high) initial biodiversity subsequently became more (less) diverse, indicating an equilibrium biodiversity status in the communities considered here. Linuron adversely affected richness and evenness while dominance increased but no biodiversity indices were different from the control treatment at linuron concentrations below 2.4 μg/L. Richness-related indices changed at lower linuron concentrations (effects noticeable from 2.4 μg/L) than other biodiversity indices (effects noticeable from 14.4 μg/L) and, in contrast to the other indices, showed no signs of recovery following chronic exposure. Phytoplankton biomass was unaffected by linuron due to functional redundancy within the phytoplankton community. Comparing thresholds for biodiversity with conventional toxicity test results showed that standard ecological risk assessments also protect biodiversity in the case of linuron.

  10. Penicillium arizonense, a new, genome sequenced fungal species, reveals a high chemical diversity in secreted metabolites

    PubMed Central

    Grijseels, Sietske; Nielsen, Jens Christian; Randelovic, Milica; Nielsen, Jens; Nielsen, Kristian Fog; Workman, Mhairi; Frisvad, Jens Christian

    2016-01-01

    A new soil-borne species belonging to the Penicillium section Canescentia is described, Penicillium arizonense sp. nov. (type strain CBS 141311T = IBT 12289T). The genome was sequenced and assembled into 33.7 Mb containing 12,502 predicted genes. A phylogenetic assessment based on marker genes confirmed the grouping of P. arizonense within section Canescentia. Compared to related species, P. arizonense proved to encode a high number of proteins involved in carbohydrate metabolism, in particular hemicellulases. Mining the genome for genes involved in secondary metabolite biosynthesis resulted in the identification of 62 putative biosynthetic gene clusters. Extracts of P. arizonense were analysed for secondary metabolites and austalides, pyripyropenes, tryptoquivalines, fumagillin, pseurotin A, curvulinic acid and xanthoepocin were detected. A comparative analysis against known pathways enabled the proposal of biosynthetic gene clusters in P. arizonense responsible for the synthesis of all detected compounds except curvulinic acid. The capacity to produce biomass degrading enzymes and the identification of a high chemical diversity in secreted bioactive secondary metabolites, offers a broad range of potential industrial applications for the new species P. arizonense. The description and availability of the genome sequence of P. arizonense, further provides the basis for biotechnological exploitation of this species. PMID:27739446

  11. Fungal diversity is not determined by mineral and chemical differences in serpentine substrates.

    PubMed

    Daghino, Stefania; Murat, Claude; Sizzano, Elisa; Girlanda, Mariangela; Perotto, Silvia

    2012-01-01

    The physico-chemical properties of serpentine soils lead to strong selection of plant species. Whereas many studies have described the serpentine flora, little information is available on the fungal communities dwelling in these sites. Asbestos minerals, often associated with serpentine rocks, can be weathered by serpentine-isolated fungi, suggesting an adaptation to this substrate. In this study, we have investigated whether serpentine substrates characterized by the presence of rocks with distinct mineral composition could select for different fungal communities. Both fungal isolation and 454 pyrosequencing of amplicons obtained from serpentine samples following direct DNA extraction revealed some fungal taxa shared by the four ophiolitic substrates, but also highlighted several substrate-specific taxa. Bootstrap analysis of 454 OTU abundances indicated weak clustering of fungal assemblages from the different substrates, which did not match substrate classification based on exchangeable macronutrients and metals. Intra-substrate variability, as assessed by DGGE profiles, was similar across the four serpentine substrates, and comparable to inter-substrate variability. These findings indicate the absence of a correlation between the substrate (mineral composition and available cations) and the diversity of the fungal community. Comparison of culture-based and culture-independent methods supports the higher taxonomic precision of the former, as complementation of the better performance of the latter.

  12. Real-Time Monitoring of Critical Care Analytes in the Bloodstream with Chemical Sensors: Progress and Challenges

    NASA Astrophysics Data System (ADS)

    Frost, Megan C.; Meyerhoff, Mark E.

    2015-07-01

    We review approaches and challenges in developing chemical sensor-based methods to accurately and continuously monitor levels of key analytes in blood related directly to the status of critically ill hospitalized patients. Electrochemical and optical sensor-based technologies have been pursued to measure important critical care species in blood [i.e., oxygen, carbon dioxide, pH, electrolytes (K+, Na+, Cl-, etc.), glucose, and lactate] in real-time or near real-time. The two main configurations examined to date for achieving this goal have been intravascular catheter sensors and patient attached ex vivo sensors with intermittent blood sampling via an attached indwelling catheter. We discuss the status of these configurations and the main issues affecting the accuracy of the measurements, including cell adhesion and thrombus formation on the surface of the sensors, sensor drift, sensor selectivity, etc. Recent approaches to mitigate these nagging performance issues that have prevented these technologies from clinical use are also discussed.

  13. Nanostructural and Chemical Characterization of Supported Metal Oxide Catalysts by Aberration Corrected Analytical Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Zhou, Wu

    In this thesis, aberration corrected STEM imaging and chemical analysis techniques have been extensively applied in the structural and chemical characterization of supported tungsten oxide catalysts in an attempt to reveal the structure-activity relationships at play in these catalyst systems. The supported WO3/ZrO2 solid acid catalyst system is a major focal point of this thesis, and detailed aberration-corrected STEM-HAADF imaging studies were performed on a systematic set of catalysts showing different level of catalytic performance. The nature of the catalytically most active WOx species was identified by correlating structural information, obtained from STEM-HAADF and in-situ optical spectroscopy studies, with catalytic testing results. Specifically, ˜1nm distorted Zr-WOx mixed oxide clusters were identified to be the most active species for both the methanol dehydration and n-pentane isomerization reactions in the WO3/ZrO2 catalyst system. The use of amorphous zirconia as a precursor support material makes it much easier to extract and incorporate Zr cations into the surface WOx clusters during calcination. The calcination temperature was also identified to also play an important role in the formation of these most active Zr-WOx clusters. When the calcination temperature is comparable to or higher than the 896K Huttig temperature of ZrO2 (at which surface ZrO x species have sufficient mobility to agglomerate and sinter), the chance for successful surface WOx and ZrOx intermixing is significantly increased. Based on this perceived structure-activity relationship, several new catalyst synthesis strategies were developed in an attempt to optimize the catalytic performance of WOx-based catalysts. We have demonstrated in Chapter 3 that co-impregnation of WOx and ZrOx precursors onto an inactive model WO3/ZrO2 catalyst, followed by a calcination treatment above the 896K Huttig temperature of ZrO 2, promotes the surface diffusion of ZrO2 and intermixing of Zr

  14. Analytical solution of steady-state equations for chemical reaction networks with bilinear rate laws.

    PubMed

    Halász, Adám M; Lai, Hong-Jian; McCabe Pryor, Meghan; Radhakrishnan, Krishnan; Edwards, Jeremy S

    2013-01-01

    True steady states are a rare occurrence in living organisms, yet their knowledge is essential for quasi-steady-state approximations, multistability analysis, and other important tools in the investigation of chemical reaction networks (CRN) used to describe molecular processes on the cellular level. Here, we present an approach that can provide closed form steady-state solutions to complex systems, resulting from CRN with binary reactions and mass-action rate laws. We map the nonlinear algebraic problem of finding steady states onto a linear problem in a higher-dimensional space. We show that the linearized version of the steady-state equations obeys the linear conservation laws of the original CRN. We identify two classes of problems for which complete, minimally parameterized solutions may be obtained using only the machinery of linear systems and a judicious choice of the variables used as free parameters. We exemplify our method, providing explicit formulae, on CRN describing signal initiation of two important types of RTK receptor-ligand systems, VEGF and EGF-ErbB1.

  15. Chemically-modified graphenes for oxidation of DNA bases: analytical parameters.

    PubMed

    Goh, Madeline Shuhua; Bonanni, Alessandra; Ambrosi, Adriano; Sofer, Zdeněk; Pumera, Martin

    2011-11-21

    We studied the electroanalytical performances of chemically-modified graphenes (CMGs) containing different defect densities and amounts of oxygen-containing groups, namely graphite oxide (GPO), graphene oxide (GO), thermally reduced graphene oxide (TR-GO) and electrochemically reduced graphene oxide (ER-GO) by comparing the sensitivity, selectivity, linearity and repeatability towards the oxidation of DNA bases. We have observed that for differential pulse voltammetric (DPV) detection of adenine and cytosine, all CMGs showed enhanced sensitivity to oxidation, while for guanine and thymine, ER-GO and TR-GO exhibited much improved sensitivity over bare glassy carbon (GC) as well as over GPO and GO. There is also significant selectivity enhancement when using GPO for adenine and TR-GO for thymine. Our results have uncovered that the differences in surface functionalities, structure and defects of various CMGs largely influence their electrochemical behaviour in detecting the oxidation of DNA bases. The findings in this report will provide a useful guide for the future development of label-free electrochemical devices for DNA analysis.

  16. Analytical Solution of Steady State Equations for Chemical Reaction Networks with Bilinear Rate Laws

    PubMed Central

    Halász, Ádám M.; Lai, Hong-Jian; McCabe, Meghan M.; Radhakrishnan, Krishnan; Edwards, Jeremy S.

    2014-01-01

    True steady states are a rare occurrence in living organisms, yet their knowledge is essential for quasi-steady state approximations, multistability analysis, and other important tools in the investigation of chemical reaction networks (CRN) used to describe molecular processes on the cellular level. Here we present an approach that can provide closed form steady-state solutions to complex systems, resulting from CRN with binary reactions and mass-action rate laws. We map the nonlinear algebraic problem of finding steady states onto a linear problem in a higher dimensional space. We show that the linearized version of the steady state equations obeys the linear conservation laws of the original CRN. We identify two classes of problems for which complete, minimally parameterized solutions may be obtained using only the machinery of linear systems and a judicious choice of the variables used as free parameters. We exemplify our method, providing explicit formulae, on CRN describing signal initiation of two important types of RTK receptor-ligand systems, VEGF and EGF-ErbB1. PMID:24334389

  17. Influence of Chemical Kinetics on Postcolumn Reaction in a Capillary Taylor Reactor with Catechol Analytes and Photoluminescence Following Electron Transfer

    PubMed Central

    Jung, Moon Chul; Weber, Stephen G.

    2006-01-01

    Postcolumn derivatization reactions can enhance detector sensitivity and selectivity, but their successful combination with capillary liquid chromatography has been limited because of the small peak volumes in capillary chromatography. A capillary Taylor reactor (CTR), developed in our laboratory, provides simple and effective mixing and reaction in a 25-μm-radius postcolumn capillary. Homogenization of reactant streams occurs by radial diffusion, and a chemical reaction follows. Three characteristic times for a given reaction process can be predicted using simple physical and chemical parameters. Two of these times are the homogenization time, which governs how long it takes the molecules in the analyte and reagent streams to mix, and the reaction time, which governs how long the molecules in a homogeneous solution take to react. The third characteristic time is an adjustment to the reaction time called the start time, which represents an estimate of the average time the analyte stream spends without exposure to reagent. In this study, laser-induced fluorescence monitored the extent of the postcolumn reaction (reduction of Os(bpy)33+ by analyte to the photoluminescent Os(bpy)32+) in a CTR. The reaction time depends on the reaction rates. Analysis of product versus time data yielded second-order reaction rate constants between the PFET reagent, tris(2,2′-bipyridine)osmium, and standards ((ferrocenylmethyl)trimethylammonium cation and p-hydroquinone) or catechols (dopamine, epinephrine, norepinephrine, 3, 4-dihydroxyphenylacetic acid. The extent of the reactions in a CTR were then predicted from initial reaction conditions and compared to experimental results. Both the theory and experimental results suggested the reactions of catechols were generally kinetically controlled, while those of the standards were controlled by mixing time (1–2 s). Thus, the extent of homogenization can be monitored in a CTR using the relatively fast reaction of the reagent and p

  18. Understanding of the impact of chemicals on amphibians: a meta-analytic review

    PubMed Central

    Egea-Serrano, Andrés; Relyea, Rick A; Tejedo, Miguel; Torralva, Mar

    2012-01-01

    Many studies have assessed the impact of different pollutants on amphibians across a variety of experimental venues (laboratory, mesocosm, and enclosure conditions). Past reviews, using vote-counting methods, have described pollution as one of the major threats faced by amphibians. However, vote-counting methods lack strong statistical power, do not permit one to determine the magnitudes of effects, and do not compare responses among predefined groups. To address these challenges, we conducted a meta-analysis of experimental studies that measured the effects of different chemical pollutants (nitrogenous and phosphorous compounds, pesticides, road deicers, heavy metals, and other wastewater contaminants) at environmentally relevant concentrations on amphibian survival, mass, time to hatching, time to metamorphosis, and frequency of abnormalities. The overall effect size of pollutant exposure was a medium decrease in amphibian survival and mass and a large increase in abnormality frequency. This translates to a 14.3% decrease in survival, a 7.5% decrease in mass, and a 535% increase in abnormality frequency across all studies. In contrast, we found no overall effect of pollutants on time to hatching and time to metamorphosis. We also found that effect sizes differed among experimental venues and among types of pollutants, but we only detected weak differences among amphibian families. These results suggest that variation in sensitivity to contaminants is generally independent of phylogeny. Some publication bias (i.e., selective reporting) was detected, but only for mass and the interaction effect size among stressors. We conclude that the overall impact of pollution on amphibians is moderately to largely negative. This implies that pollutants at environmentally relevant concentrations pose an important threat to amphibians and may play a role in their present global decline. PMID:22957147

  19. Application of chemical, physical and chemometric analytical techniques to the study of ancient ceramic oil lamps.

    PubMed

    García Giménez, R; Vigil de la Villa, R; Petit Domínguez, M D; Rucandio, M I

    2006-02-15

    A chemical, mineralogical and morphological characterization of 54 fragments of oil lamps found in two Spanish archaeological sites (Cordoba and Herrera de Pisuerga (Palencia)) has been performed. Flame atomic absorption and emission spectrometry were used for the determination of Al(2)O(3), CaO, Fe(2)O(3), K(2)O, MgO, MnO, Na(2)O and TiO(2) as major constituents and Cu, Cr, Ni, Pb and Zn as minor and trace selected elements. Physical, mineralogical and morphological analyses were made by using dilatometry at constant heating rate for the thermal behaviour, X-ray diffraction spectrometry for the mineralogical composition and, in a group of selected samples, scanning electron microscopy and polarizing petrographic microscopy for the observation of thin layers and mineral identification. Separations of light and heavy minerals were carried out with bromoform and X-ray diffraction analysis was applied to both fractions. Multivariate statistical analysis was used to establish correlations between variables and to deduce factors which allow the gathering of oil lamp samples in groups as a function of their composition. The results of these analyses allow the comparison among pieces and the establishment of conclusions about several aspects of their manufacture, the origin of the raw materials and the provenance of the oil lamps (local or imported). They provide information supporting certain archaeological hypothesis. For example, some oil lamps found in Herrera de Pisuerga showed a clearly different physicochemical composition. They were probably brought from Italy by the Roman Legions together with their initial furniture household.

  20. Analysis of chemical weapons decontamination waste from old ton containers from Johnston Atoll using multiple analytical methods

    SciTech Connect

    Creasy, W.R.; Brickhouse, M.D.; Morrisse, K.M.

    1999-07-01

    Decontamination waste from chemical weapons (CW) agents has been stored in ton containers on Johnston Atoll since 1971. The waste was recently sampled and analyzed to determine its chemical composition in preparation for future cleanups. Due to the range of products and analytical requirements, multiple chromatographic and spectroscopic methods were necessary, including gas chromatography/mass spectrometry (GC/MS), gas chromatography/atomic emission detection (GC/AED), liquid chromatography/mass spectrometry (LC/MS), capillary electrophoresis (CE), and nuclear magnetic resonance spectroscopy (NMR). The samples were screened for residual agents. No residual sarin (GB) or VX was found to detection limits of 20 ng/mL, but 3% of the samples contained residual sulfur mustard (HD) at < 140 ng/mL. Decontamination products of agents were identified. The majority (74%) of the ton containers were documented correctly, in that the observed decontamination products were in agreement with the labeled agent type, but for a number of the containers, the contents were not in agreement with the labels. In addition, arsenic compounds that are decontamination products of the agent lewisite (L) were observed in a few ton containers, suggesting that lewisite was originally present but not documented. This study was a prototype to demonstrate the level of effort required to characterize old bulk CW-related waste.

  1. One year of chemical diversity seen by ChemCam at Gale crater, Mars

    NASA Astrophysics Data System (ADS)

    Gasnault, Olivier; Wiens, Roger; Maurice, Sylvestre; Meslin, Pierre-Yves; Forni, Olivier; Leveillé, Richard; Bridges, Nathan; Lasue, Jérémie; Le Mouélic, Stéphane; Mangold, Nicolas; Sautter, Violaine

    2014-05-01

    ChemCam, the chemistry remote camera, has observed more than 300 different targets (rocks and soils) over the course of the first 360 Sols on Mars. This presentation gives an overview of the chemical variations revealed by ChemCam onboard the rover Curiosity. At the submillimeter scale, ChemCam identified two principal soil types: A fine-grained mafic type and a type made of coarse grains of diverse compositions [1]. The mafic soil component is similar to soils found at other landing sites, and may constitute a planet-wide reservoir. It possesses a ubiquitous hydration [2] in its amorphous phase, which may account for a significant fraction of the global hydration. The second soil component is made of pebbles, sometimes buried in the soil, and partly matches the diversity of chemical compositions found in the surrounding float rocks at the landing site [3]. The felsic end member appears to be specific to Gale crater, compared to other landing sites so far, and may be derived from coarse-grained intrusive rocks representing the ancient crust and transported from the crater rim [4]. Curiosity also came across many sedimentary rocks [5,6,7]. The 5 km deposits at the Yellowknife Bay formation testify prolonged aqueous activities relatively late in the history of early Mars, possibly in series of episodes: transport and sedimentation with little alteration, diagenesis partially into clays, and fluids circulation all along the unit formation through fractures, with a water activity more or less limited. Early diagenetic cracks in the lower most exposed unit appear to be filled with erosion-resistant raised ridges [8], that ChemCam has shown to be enriched in Mg- and Fe-rich clays [9]. The calcium sulfate veins (gypsum, bassanite) on the other hand are found all across the deposit and must have formed last [10]. In a large majority, rocks and coarse gravels encountered so far by Curiosity show little surface coatings but dust. However, some water-rock interaction

  2. Earle K. Plyler Prize for Molecular Spectroscopy & Dynamics Lecture: Broadband Rotational Spectroscopy for Chemical Kinetics, Molecular Structure, and Analytical Chemistry

    NASA Astrophysics Data System (ADS)

    Pate, Brooks

    2013-03-01

    Advances in high-speed digital electronics have enabled a new generation of molecular rotational spectroscopy techniques that provide instantaneous broadband spectral coverage. These techniques use a chirped excitation pulse to coherently excite the molecular sample over a spectral bandwidth of 10 GHz or larger through rapid passage. The subsequent time-domain emission is recorded using high-speed digitizers (up to 100 Gigasample/s) and the frequency domain spectrum is produced by fast Fourier transformation. The chirped-pulse Fourier transform (CP-FT) method has been implemented in the microwave frequency range (2-40 GHz) for studies of cold samples in pulsed jet sources and in the mm-wave/terahertz (THz) frequency range for studies of samples at room-temperature. The method has opened new applications for molecular rotational spectroscopy in the area of chemical kinetics where dynamic rotational spectroscopy is used to measure the rates of unimolecular isomerization reactions in highly excited molecules prepared by pulsed infrared laser excitation. In these applications, the isomerization rate is obtained from an analysis of the overall line shapes which are modified by chemical exchange leading to coalescence behavior similar to the effect in NMR spectroscopy. The sensitivity of the method and the ability to extend it to low frequency (2-8 GHz) have significantly increased the size range of molecules and molecular clusters for structure determination using isotopic substitution to build up the 3D molecular structures atom-by-atom. Application to the structure of water clusters with up to 15 water molecules will be presented. When coupled with advances in solid-state mm-wave/THz devices, this method provides a direct digital technique for analytical chemistry of room-temperature gases based on molecular rotational spectroscopy. These high-throughput methods can analyze complex sample mixtures with unmatched chemical selectivity and short analysis times. Work

  3. Using Narrative as a Data Source and Analytic Method to Investigate Learning Outside of Traditional School Settings with Diverse Youth

    ERIC Educational Resources Information Center

    Martell, Sandra Toro; Antrop-Gonzalez, Rene

    2008-01-01

    Narrative is used to describe and understand how people construct meaning of their lives and experiences and how they think about their own and others' identities. We examined narrative as both data source and method of analysis for investigating learning in non-traditional school settings with students from diverse socio-economic status and…

  4. Using the Conceptual Change Model of Learning as An Analytic Tool in Researching Teacher Preparation for Student Diversity

    ERIC Educational Resources Information Center

    Larkin, Douglas

    2012-01-01

    Background/Context: In regard to preparing prospective teachers for diverse classrooms, the agenda for teacher education research has been primarily concerned with identifying desired outcomes and promising strategies. Scholarship in multicultural education has been crucial for identifying the knowledge, skills, and attitudes needed by teachers to…

  5. [The analytical setting of rotary speed of centrifuge rotor and centrifugation time in chemical, biochemical and microbiological practice].

    PubMed

    Zolotarev, K V

    2012-08-01

    The researchers happen to face with suspensions in their chemical, biochemical and microbiological practice. The suspensions are the disperse systems with solid dispersed phase and liquid dispersion medium and with dispersed phase particle size > 100 nm (10-7 m). Quite often the necessity occurs to separate solid particles from liquid. To use for this purpose the precipitation in gravitation field can make the process to progress too long. In this respect an effective mode is the precipitation in the field of centrifugal forces--the centrifugation. The rotary speed of centrifuge rotor and centrifugation time can be set analytically using regularities of general dynamics and hydrodynamics. To this effect, should be written and transformed the equation of First and Second Newton Laws for suspension particle being in the field of centrifugal forces and forces of resistance of liquid and vessel wall. The force of liquid resistance depends on particle motion condition in liquid. To determine the regimen the Archimedes and Reynolds numerical dimensionless criteria are to be applied. The article demonstrates the results of these transformations as analytical inverse ratio dependence of centrifugation time from rotary speed. The calculation of series of "rate-time" data permits to choose the optimal data pair on the assumption of centrifuge capacity and practical reasonability. The results of calculations are validated by actual experimental data hence the physical mathematical apparatus can be considered as effective one. The setting progress depends both from parameter (Reynolds criterion) and data series calculation. So, the most convenient way to apply this operation is the programming approach. The article proposes to use the program Microsoft Excel and VBA programming language for this purpose. The possibility to download the file from Internet to use it for fast solution is proposed.

  6. Determination of fumaric and maleic acids with stacking analytes by transient moving chemical reaction boundary method in capillary electrophoresis.

    PubMed

    He, Jian-Feng; Yang, Wei-Ying; Yao, Fu-Jun; Zhao, Hong; Li, Xiang-Jun; Yuan, Zhuo-Bin

    2011-06-17

    The paper presents an on-line transient moving chemical reaction boundary (MCRB) method for simply but efficiently stacking analytes in capillary electrophoresis (CE). The CE technique was developed for a rapid determination of fumaric and maleic acid. Based on the theory of MCRB, Effects of several important factors such as the pH and concentration of running buffer and the conditions of stacking analytes were investigated to acquire the optimum conditions. The optimized separations were carried out in a 20 mmol/L sulphate neutralized with ethylenediamine to pH 6.0 electrolytes using a capillary coated with poly (diallyldimethylammonium chloride) and direct UV detection at 214 nm. The optimized preconcentrations were carried out in 50 mmol/L borax (pH 9.0). The calibration curves were linear in the concentration range of 1.0×10⁻⁷-1.0×10⁻⁴ mol/L and 5.0×10⁻⁷-1.0×10⁻⁴ mol/L for fumaric and maleic acid with correlation coefficients higher than 0.9991. The detection limits were 5.34×10⁻⁸ mol/L for fumaric acid and 1.92×10⁻⁷ mol/L for maleic acid. This method was applied for determination of fumaric acid in apple juice and of fumaric and maleic acid in dl-malic, the recovery tests established for real samples were within the range 95-105%. This work provided a valid and simple approach to detect fumaric and maleic acid.

  7. Two-column sequential injection chromatography for fast isocratic separation of two analytes of greatly differing chemical properties.

    PubMed

    Šatínský, Dalibor; Chocholouš, Petr; Válová, Olga; Hanusová, Lucia; Solich, Petr

    2013-09-30

    This paper deals with a novel approach to separate two analytes with different chemical properties and different lipophilicity. The newly described methodology is based on the two column system that was used for isocratic separation of two analytes with very different lipophilicity-dexamethasone and cinchocaine. Simultaneous separation of model compounds cinchocaine and dexamethasone was carried under the following conditions in two-column sequential injection chromatography system (2-C SIC). A 25×4.6 mm C-18 monolithic column was used in the first dimension for retention and separation of dexamethasone with mobile phase acetonitrile:water 30:70 (v/v), flow rate 0.9 mL min(-1) and consumption of 1.7 mL. A 10×4.6 mm C-18 monolithic column with 5×4.6 mm C-18 precolumn was used in the second dimension for retention and separation of cinchocaine using mobile phase acetonitrile:water 60:40 (v/v), flow rate 0.9 mL min(-1) and consumption 1.5 mL. Whole analysis time including both mobile phase's aspirations and both column separations was performed in less than 4 min. The method was fully validated and used for determination of cinchocaine and dexamethasone in pharmaceutical otic drops. The developed 2-C SIC method was compared with HPLC method under the isocratic conditions of separation on monolithic column (25×4.6 mm C-18). Spectrophotometric detection of both compounds was performed at wavelength 240 nm. System repeatability and method precision were found in the range (0.39-3.12%) for both compounds. Linearity of determination was evaluated in the range 50-500 μg mL(-1) and coefficients of determination were found to be r(2)=0.99912 for dexamethasone and r(2)=0.99969 for cinchocaine.

  8. Environmental toxicological fate prediction of diverse organic chemicals based on steady-state compartmental chemical mass ratio using quantitative structure-fate relationship (QSFR) models.

    PubMed

    Pramanik, Subrata; Roy, Kunal

    2013-07-01

    Four quantitative prediction models for steady-state compartmental chemical mass concentrations (Wn,g) were obtained from structural information, physiochemical properties, degradation rate and transport coefficients of 455 diverse organic chemicals using chemometric tools in a quantitative structure-fate relationship (QSFR) study. The mass ratio assessment of environmentally prevalent organic chemicals may be helpful to predict their toxicological fate in the ecosystems. Four sets of mass ratios [(1) log(Wair) from water emissions (water to air compartment), (2) log(Wair) from air emissions (within different zones of the air compartment), (3) log(Wwater) from water emissions (within different zones of the water compartment) and (4) log(Wwater) from air emissions (air to water compartment)] have been used. The developed models using genetic function approximation followed by multiple linear regression (GFA-MLR) and subsequent partial least squares (PLS) treatment identify only four descriptors for log(Wair) from water emission, six descriptors for log(Wair) from air emission, five descriptors for log(Wwater) from water emission and seven descriptors for log(Wwater) from air emission for predicting efficiently a large number of test set chemicals (ntest=182). The conclusive models suggest that descriptors such as partition coefficients (Kaw, Kow and Ksw), degradation parameters (Ksoil,Kwater and Kair), vapor pressure (Pv), diffusivity (Dwater), spatial descriptors (Jurs-WNSA-1, Jurs-WNSA-2, Jurs-WPSA-3, Jurs-FNSA-3 and Density), thermodynamic descriptors (MolRef and AlogP98), electrotopological state indices (S_dsN, S_ssNH and S_dsCH) are important for predicting the chemical mass ratios. The developed models may be applicable in toxicological fate prediction of diverse chemicals in the ecosystems.

  9. Sample Collection Information Document for Chemical & Radiochemical Analytes – Companion to Selected Analytical Methods for Environmental Remediation and Recovery (SAM) 2012

    EPA Pesticide Factsheets

    Sample Collection Information Document is intended to provide sampling information to be used during site assessment, remediation and clearance activities following a chemical or radiological contamination incident.

  10. Analytical Method for the Detection of Ozone Depleting Chemicals (ODC) in Commercial Products Using a Gas Chromatograph with an Electron Capture Detector (GC-ECD)

    SciTech Connect

    Lee, Richard N.; Dockendorff, Brian P.; Wright, Bob W.

    2008-08-01

    This document describes an analytical procedure that was developed for the trace level detection of residual ozone depleting chemicals (ODC) associated with the manufacture of selected commercial products. To ensure the United States meets it obligation under the Montreal Protocol, Congress enacted legislation in 1989 to impose an excise tax on electronic goods imported into the United States that were produced with banned chemicals. This procedure was developed to technically determine if residual ODC chemicals could be detected on electronic circuit boards. The analytical method utilizes a “purge and trap” technique followed by gas chromatography with electron capture detection to capture and analyze the volatile chemicals associated with the matrix. The method describes the procedure, the hardware, operating conditions, calibration, and quality control measures in sufficient detail to allow the capability to be replicated. This document corresponds to internal Standard Operating Procedure (SOP) EFL-130A, Rev 4.

  11. Nature of the binding interaction for 50 structurally diverse chemicals with rat estrogen receptors

    EPA Science Inventory

    This study was conducted to characterize the estrogen receptor (ER)-binding affinities of 50 chemicals selected from among the high production volume chemicals under the U.S. EPA's (U.S. Environmental Protection Agency's) Toxic Substances Control Act inventory. The chemicals were...

  12. Identification of improvised explosives residues using physical-chemical analytical methods under real conditions after an explosion

    NASA Astrophysics Data System (ADS)

    Kotrlý, Marek; Mareš, Bohumil; Turková, Ivana; Beroun, Ivo

    2016-05-01

    Within the analysis of cases relating to the use of explosives for crimes, we have experienced a shift from using industrial explosives towards substances made in amateur and illegal way. Availability of industrial explosives is increasingly limited to a narrow sphere of subjects with a relevant permission. Thus, on the part of perpetrators, terrorists, ever greater attention is paid to illegal production of explosives that are easily made from readily available raw materials. Another alarming fact is the availability of information found on the internet. Procedures of preparation are often very simple and do not require even a deeper professional knowledge. Explosive characteristics are not actually accessible for many of these substances (detonation velocity, sensitivity, working capacity, brisance, physical and chemical stability, etc.). Therefore, a project is being implemented, which on grounds of assessment of individual information available in literature and on the internet, aiming at choosing individual areas of potentially abusable substances (e.g. mixtures of nitric acid (98%) with organic substances, mixtures nitromethane and tetranitromethane with organic substances, mixtures of chlorates and perchlorates of alkali metals with organic substances, chemically individual compounds of organic base type of perchloric acid, azides, fulminates, acetylides, picrates, styphnates of heavy metals, etc.). It is directed towards preparation of these explosives also in non-stoichiometric mixtures, conducting test explosives, determination of explosive characteristics (if they are unknown) and analysis of both primary phases and post-blast residues through available analytical techniques, such as gas and liquid chromatography with mass detection, FTIR, micro-Raman spectrometry, electron microscopy with microanalysis and Raman microspectrometry directly in SEM chamber for analysis at the level of individual microparticles. The received characteristics will be used to

  13. Material Characterization in the Electro-Analytic Approach for Applications in Chemical Mechanical Planarization and Electrochemical Energy Systems

    NASA Astrophysics Data System (ADS)

    Rock, Simon E.

    The work presented in this thesis covers electro-analytical characterization for multiple applications in material science. Electrochemical techniques were used to investigate soluble film formation on metals used in chemical mechanical planarization in order to better understand the removal rate process by studying new chemicals proposed by groups in industry. Second, an ionic liquid was used as an electrolyte in a lithium ion cathode half cell to show the essential functionality of the IL and the temperature advantage over traditional electrolytes. Lastly, a comprehensive measurement for charge recombination in dye-sensitized solar cells was performed using both open-circuit voltage decay and impedance spectroscopy, which may be used to better understand the limiting factors that affect the cell's efficiently. Electrochemical techniques were applied to new methods and materials to extend the development of material manufacturing and advance the measurement process. The fabrication of interconnect structures for semiconductor devices requires low down-pressure chemical mechanical planarization (CMP) of Ta barrier layers. Guanidine carbonate (GC) serves as an effective surface-complexing agent for such CMP applications, where the rate of Ta removal can be chemically controlled through pH-tuned selectivity with respect to the removal of Cu lines. Electrochemical techniques are employed in this work to study the surface-modifying roles of GC that make this chemical an attractive complexing agent for Ta CMP. In addition, the effects of including H2O2 (an oxidizer) and dodecyl benzene sulfonic acid (DBSA, a dissolution inhibitor for Cu) in GC-based CMP solutions are investigated to examine the selective CMP mechanisms of Ta and Cu in these solutions. The results suggest that the removal of Ta is supported in part by structurally weak guanidinium-tantalic-acid surface complexes formed on Ta/Ta2O5. The bicarbonate/carbonate anions of GC also facilitate Ta removal through

  14. QSTR modeling for qualitative and quantitative toxicity predictions of diverse chemical pesticides in honey bee for regulatory purposes.

    PubMed

    Singh, Kunwar P; Gupta, Shikha; Basant, Nikita; Mohan, Dinesh

    2014-09-15

    Pesticides are designed toxic chemicals for specific purposes and can harm nontarget species as well. The honey bee is considered a nontarget test species for toxicity evaluation of chemicals. Global QSTR (quantitative structure-toxicity relationship) models were established for qualitative and quantitative toxicity prediction of pesticides in honey bee (Apis mellifera) based on the experimental toxicity data of 237 structurally diverse pesticides. Structural diversity of the chemical pesticides and nonlinear dependence in the toxicity data were evaluated using the Tanimoto similarity index and Brock-Dechert-Scheinkman statistics. Probabilistic neural network (PNN) and generalized regression neural network (GRNN) QSTR models were constructed for classification (two and four categories) and function optimization problems using the toxicity end point in honey bees. The predictive power of the QSTR models was tested through rigorous validation performed using the internal and external procedures employing a wide series of statistical checks. In complete data, the PNN-QSTR model rendered a classification accuracy of 96.62% (two-category) and 95.57% (four-category), while the GRNN-QSTR model yielded a correlation (R(2)) of 0.841 between the measured and predicted toxicity values with a mean squared error (MSE) of 0.22. The results suggest the appropriateness of the developed QSTR models for reliably predicting qualitative and quantitative toxicities of pesticides in honey bee. Both the PNN and GRNN based QSTR models constructed here can be useful tools in predicting the qualitative and quantitative toxicities of the new chemical pesticides for regulatory purposes.

  15. Analytical procedures and quality-assurance plan for the determination of xenobiotic chemical contaminants in fish. National dioxin study. Phase 2

    SciTech Connect

    Not Available

    1989-12-01

    The report describes the analytical procedures and quality assurance plan used for the determination of xenobiotic chemical contaminants including select pesticides, polynuclear aromatic hydrocarbons, and polychlorinated biphenyls for Phase II of the U.S. EPA National Dioxin Study. These methods are based upon compound identification and quantification by gas chromatography-mass spectrometry.

  16. EFFECTS OF CHEMICAL CONTAMINANTS ON GENETIC DIVERSITY IN NATURAL POPULATIONS: IMPLICATIONS FOR BIOMONITORING AND ECOTOXICOLOGY

    EPA Science Inventory

    The conservation of genetic diversity has emerged as one of the central issues in conservation biology. Although researchers in the areas of evolutionary biology, population management, and conservation biology routinely investigate genetic variability in natural populations, onl...

  17. Biological and Physico-chemical Processes of Soil Organic Matter Cycling in Diverse Soils

    NASA Astrophysics Data System (ADS)

    Jagadamma, S.; Mayes, M. A.; Steinweg, J. M.; Post, W. M.; Wang, G.

    2011-12-01

    Soils comprise the largest biologically active terrestrial pool of organic carbon (OC). The top meter of soil contains 1500 Pg of OC which is 3 times that present in vegetation and two times the CO2-C present in atmosphere. Current soil C models simulate soil C pool sizes and turnover rates on post-hoc basis and the mechanisms governing soil OC cycling have not been integrated in such models. Therefore the scale of applicability and accuracy of predictions of current C models are questionable. Our current efforts are focused on developing a mechanistic framework of soil C cycling processes and its linkage to global C model. As part of this effort, we seek to understand the important cycling and interactive processes of OC compounds with the soil minerals and microbial community on a global suite of soils from temperate, tropical and arctic ecosystems. The selected OC compounds are glucose, cellulose, stearic acid and vanillic acid which are representative of SOM composition that contains 5-15% sugars, 20-50% starch, 10% proteins, 20-30% lignin and 2-5% lipids. We hypothesize that physico-chemical interactions between OC compounds and soil minerals determines the biological stability and distribution of such compounds in soils. Cycling of the selected 14C-labeled OC compounds were investigated as a function of soil type, soil depth and functional components of SOM (dissolved organic carbon, DOC; particulate organic matter, POM; and mineral associated organic matter, MAOM). This presentation will consist of the results from sorption and long-term incubation experiments conducted on diverse soils by the addition of 14C-glucose. Sorption of 14C-glucose on soil minerals was determined by batch equilibration experiments of MAOM fraction at a solid-to-solution ratio of 1:60 for 8 hours. A series of initial glucose solutions containing 0-100 mg C/L unlabeled C and 4000 dpm/ml labeled C were used. Maximum sorption capacity (Qmax) and affinity coefficient (K) were determined

  18. Growth of Daphnia magna exposed to mixtures of chemicals with diverse modes of action

    SciTech Connect

    Deneer, J.W.; Seinen, W.; Hermens, J.L.

    1988-02-01

    Concentrations causing inhibition of growth of Daphnia magna after 16 days of exposure were determined for nine chemicals that presumably act through different modes of action. The joint toxic effect of a mixture of these chemicals is found to be nonadditive.

  19. Sorption of a diverse set of organic chemical vapors onto XAD-2 resin: Measurement, prediction and implications for air sampling

    NASA Astrophysics Data System (ADS)

    Hayward, Stephen J.; Lei, Ying D.; Wania, Frank

    2011-01-01

    The wide-spread use of styrene-divinylbenzene-copolymeric resin (XAD-2) in air sampling necessitates a quantitative understanding of its sorption characteristics for organic chemicals. Inverse Gas Chromatography (IGC) was used to measure the sorption of a diverse set of 52 organic chemicals to XAD-2 at temperatures between 40 °C and 100 °C and at relative humidities between 0 and 87%. Even though relative humidity has been shown to influence sorption to other sorbents, it did not significantly influence most chemicals' sorption to XAD-2, indicating that water does not form a strong physical barrier to sorption on XAD-2 at high relative humidity. The resin-air partition coefficients ( KXAD) determined by IGC and the enthalpies of sorption derived from them were regressed against solute descriptors to derive poly-parameter Linear Free Energy Relationships (ppLFERs) which allow the estimation of KXAD for chemicals which are not sufficiently volatile to be amenable to IGC and for temperatures outside the experimental range. KXAD values at 20 °C estimated for a set of 296 chemicals for which solute descriptors are available, including polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and pesticides, indicate that for many of the substances commonly found in the atmosphere sorption is higher to XAD-2 than to poly-urethane foam, another popular air sampling sorbent.

  20. Role of vermicompost chemical composition, microbial functional diversity, and fungal community structure in their microbial respiratory response to three pesticides.

    PubMed

    Fernández-Gómez, Manuel J; Nogales, Rogelio; Insam, Heribert; Romero, Esperanza; Goberna, Marta

    2011-10-01

    The relationships between vermicompost chemical features, enzyme activities, community-level physiological profiles (CLPPs), fungal community structures, and its microbial respiratory response to pesticides were investigated. Fungal community structure of vermicomposts produced from damaged tomato fruits (DT), winery wastes (WW), olive-mill waste and biosolids (OB), and cattle manure (CM) were determined by denaturing gradient gel electrophoresis of 18S rDNA. MicroResp™ was used for assessing vermicompost CLPPs and testing the microbial response to metalaxyl, imidacloprid, and diuron. Vermicompost enzyme activities and CLPPs indicated that WW, OB, and DT had higher microbial functional diversity than CM. The microbiota of the former tolerated all three pesticides whereas microbial respiration in CM was negatively affected by metalaxyl and imidacloprid. The response of vermicompost microbiota to the fungicide metalaxyl was correlated to its fungal community structure. The results suggest that vermicomposts with higher microbial functional diversity can be useful for the management of pesticide pollution in agriculture.

  1. Size, number and chemical composition of nanosized particles in drinking water determined by analytical microscopy and LIBD.

    PubMed

    Kaegi, R; Wagner, T; Hetzer, B; Sinnet, B; Tzvetkov, G; Boller, M

    2008-05-01

    In this paper we comprehensively characterized particles in drinking water originating from a lake water source. We focused on particles smaller than a few hundred nm. Several analytical techniques were applied to obtain information on number concentration, size distribution, morphology and chemical composition of the particles. Morphological information was obtained by atomic force microscopy (AFM) analysis. Two types of particles, spherical aggregates up to a few tens of nm and elongated fibers were identified. Similar structures were also observed in transmission electron microscope (TEM) images. A size distribution of the particles was obtained by applying image analysis (IA) tools on the TEM images. IA results showed an exponential increase of the particle number concentration down to 40 nm, which is the lower detection limit of our setup. The total number of particles down to 10 nm and the average particle diameter were determined with the laser-induced breakdown detection (LIBD) method. The results were in good agreement with the TEM-IA data and showed a total number concentration of roughly 10(8) particles/mL in the purified water. The carbon of the particles was investigated with scanning transmission X-ray microscopy (STXM), which revealed that most particles were organic matter; the C-1s spectra were typical for dissolved organic matter. The methods were applied to characterize the particles from two different drinking waters treated with different methods (conventional vs. ultrafiltration (cut-off 100 kDa)). The results showed that the particle number density following ultrafiltration was lower by a factor of 5-10, compared to conventional treatment. However, the average particle diameter in the finished water of both treatment trains was roughly the same.

  2. Chemical Analysis of a "Miller-Type" Complex Prebiotic Broth. Part I: Chemical Diversity, Oxygen and Nitrogen Based Polymers

    NASA Astrophysics Data System (ADS)

    Wollrab, Eva; Scherer, Sabrina; Aubriet, Frédéric; Carré, Vincent; Carlomagno, Teresa; Codutti, Luca; Ott, Albrecht

    2016-06-01

    In a famous experiment Stanley Miller showed that a large number of organic substances can emerge from sparking a mixture of methane, ammonia and hydrogen in the presence of water (Miller, Science 117:528-529, 1953). Among these substances Miller identified different amino acids, and he concluded that prebiotic events may well have produced many of Life's molecular building blocks. There have been many variants of the original experiment since, including different gas mixtures (Miller, J Am Chem Soc 77:2351-2361, 1955; Oró Nature 197:862-867, 1963; Schlesinger and Miller, J Mol Evol 19:376-382, 1983; Miyakawa et al., Proc Natl Acad Sci 99:14,628-14,631, 2002). Recently some of Miller's remaining original samples were analyzed with modern equipment (Johnson et al. Science 322:404-404, 2008; Parker et al. Proc Natl Acad Sci 108:5526-5531, 2011) and a total of 23 racemic amino acids were identified. To give an overview of the chemical variety of a possible prebiotic broth, here we analyze a "Miller type" experiment using state of the art mass spectrometry and NMR spectroscopy. We identify substances of a wide range of saturation, which can be hydrophilic, hydrophobic or amphiphilic in nature. Often the molecules contain heteroatoms, with amines and amides being prominent classes of molecule. In some samples we detect ethylene glycol based polymers. Their formation in water requires the presence of a catalyst. Contrary to expectations, we cannot identify any preferred reaction product. The capacity to spontaneously produce this extremely high degree of molecular variety in a very simple experiment is a remarkable feature of organic chemistry and possibly prerequisite for Life to emerge. It remains a future task to uncover how dedicated, organized chemical reaction pathways may have arisen from this degree of complexity.

  3. Chemical Analysis of a "Miller-Type" Complex Prebiotic Broth: Part I: Chemical Diversity, Oxygen and Nitrogen Based Polymers.

    PubMed

    Wollrab, Eva; Scherer, Sabrina; Aubriet, Frédéric; Carré, Vincent; Carlomagno, Teresa; Codutti, Luca; Ott, Albrecht

    2016-06-01

    In a famous experiment Stanley Miller showed that a large number of organic substances can emerge from sparking a mixture of methane, ammonia and hydrogen in the presence of water (Miller, Science 117:528-529, 1953). Among these substances Miller identified different amino acids, and he concluded that prebiotic events may well have produced many of Life's molecular building blocks. There have been many variants of the original experiment since, including different gas mixtures (Miller, J Am Chem Soc 77:2351-2361, 1955; Oró Nature 197:862-867, 1963; Schlesinger and Miller, J Mol Evol 19:376-382, 1983; Miyakawa et al., Proc Natl Acad Sci 99:14,628-14,631, 2002). Recently some of Miller's remaining original samples were analyzed with modern equipment (Johnson et al. Science 322:404-404, 2008; Parker et al. Proc Natl Acad Sci 108:5526-5531, 2011) and a total of 23 racemic amino acids were identified. To give an overview of the chemical variety of a possible prebiotic broth, here we analyze a "Miller type" experiment using state of the art mass spectrometry and NMR spectroscopy. We identify substances of a wide range of saturation, which can be hydrophilic, hydrophobic or amphiphilic in nature. Often the molecules contain heteroatoms, with amines and amides being prominent classes of molecule. In some samples we detect ethylene glycol based polymers. Their formation in water requires the presence of a catalyst. Contrary to expectations, we cannot identify any preferred reaction product. The capacity to spontaneously produce this extremely high degree of molecular variety in a very simple experiment is a remarkable feature of organic chemistry and possibly prerequisite for Life to emerge. It remains a future task to uncover how dedicated, organized chemical reaction pathways may have arisen from this degree of complexity.

  4. Political and clinical developments in analytical psychology, 1972-2014: subjectivity, equality and diversity-inside and outside the consulting room.

    PubMed

    Samuels, Andrew

    2014-11-01

    Utilizing Jung's idea of theory as a 'personal confession', the author charts his own development as a theorist, establishing links between his personal history and his ideas. Such links include his relationship with both parents, his sexuality, his cultural heritage, and his fascination with Tricksters and with Hermes. There follows a substantial critical interrogation of what the author discerns as the two main lines of clinical theorizing in contemporary analytical psychotherapy: interpretation of transference-countertransference, and the relational approach. His conclusion is that neither is superior to the other and neither is in fact adequate as a basis for clinical work. The focus then shifts to explore a range of political and social aspects of the clinical project of analytical psychology: economic inequality, diversity within the professional field, and Jung's controversial ideas about Jews and Africans. The author calls for an apology from the 'Jungian community' for remarks about Africans analogous to the apology already issued for remarks about Jews. The paper is dedicated to the author's friend Fred Plaut (1913-2009).

  5. Assessing metabolomic and chemical diversity of a soybean lineage representing 35 years of breeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information on crop genotype- and phenotype-metabolite associations can be of value to trait development as well as to food security and safety. The unique study presented here assessed seed metabolomic and ionomic diversity in a soybean lineage representing ~35 years of breeding (launch years 1972-...

  6. Assessing the effects of adsorptive polymeric resin additions on fungal secondary metabolite chemical diversity

    PubMed Central

    González-Menéndez, Víctor; Asensio, Francisco; Moreno, Catalina; de Pedro, Nuria; Monteiro, Maria Candida; de la Cruz, Mercedes; Vicente, Francisca; Bills, Gerald F.; Reyes, Fernando; Genilloud, Olga; Tormo, José R.

    2014-01-01

    Adsorptive polymeric resins have been occasionally described to enhance the production of specific secondary metabolites (SMs) of interest. Methods that induce the expression of new chemical entities in fungal fermentations may lead to the discovery of new bioactive molecules and should be addressed as possible tools for the creation of new microbial chemical libraries for drug lead discovery. Herein, we apply both biological activity and chemical evaluations to assess the use of adsorptive resins as tools for the differential expression of SMs in fungal strain sets. Data automation approaches were applied to ultra high performance liquid chromatography analysis of extracts to evaluate the general influence in generating new chemical entities or in changing the production of specific SMs by fungi grown in the presence of resins and different base media. PMID:25379340

  7. Qualitative and quantitative structure-activity relationship modelling for predicting blood-brain barrier permeability of structurally diverse chemicals.

    PubMed

    Gupta, S; Basant, N; Singh, K P

    2015-01-01

    In this study, structure-activity relationship (SAR) models have been established for qualitative and quantitative prediction of the blood-brain barrier (BBB) permeability of chemicals. The structural diversity of the chemicals and nonlinear structure in the data were tested. The predictive and generalization ability of the developed SAR models were tested through internal and external validation procedures. In complete data, the QSAR models rendered ternary classification accuracy of >98.15%, while the quantitative SAR models yielded correlation (r(2)) of >0.926 between the measured and the predicted BBB permeability values with the mean squared error (MSE) <0.045. The proposed models were also applied to an external new in vitro data and yielded classification accuracy of >82.7% and r(2) > 0.905 (MSE < 0.019). The sensitivity analysis revealed that topological polar surface area (TPSA) has the highest effect in qualitative and quantitative models for predicting the BBB permeability of chemicals. Moreover, these models showed predictive performance superior to those reported earlier in the literature. This demonstrates the appropriateness of the developed SAR models to reliably predict the BBB permeability of new chemicals, which can be used for initial screening of the molecules in the drug development process.

  8. Computer-assisted mechanistic structure-activity studies: application to diverse classes of chemical carcinogens.

    PubMed Central

    Loew, G H; Poulsen, M; Kirkjian, E; Ferrell, J; Sudhindra, B S; Rebagliati, M

    1985-01-01

    In the first part of this paper we have indicated how the techniques and capabilities of theoretical chemistry, together with experimental results, can be used in a mechanistic approach to structure-activity studies of toxicity. In the second part, we have illustrated how this computer-assisted approach has been used to identify and calculate causally related molecular indicators of relative carcinogenic activity in five classes of chemical carcinogens: polycyclic aromatic hydrocarbons and their methyl derivatives, aromatic amines, chloroethanes, chloroalkenes and dialkyl nitrosamines. In each class of chemicals studied, candidate molecular indicators have been identified that could be useful in predictive screening of unknown compounds. In addition, further insights into some mechanistic aspects of chemical carcinogenesis have been obtained. Finally, experiments have been suggested to both verify the usefulness of the indicators and test their mechanistic implications. PMID:3905382

  9. Comparison Between a Rapid Biological Screening Method (EPA 4425) for TCDDs/TCDFs and Chemical Analytical Methods

    SciTech Connect

    Anderson, Jack W.; Jones, Jennifer M.; McCoy, Daniel L.; Fujita, Akira; Yamamoto, Taichi; Iijima, Satoshi

    2003-08-01

    Seven polychlorinated dibenzo-p-dioxins (PCDDs), ten polychlorinated dibenzofurans (PCDFs) as well as twelve polychlorinated biphenyls (PCBs) are collectively referred to as dioxin-like compounds. The World Health Organization toxic equivalency factors (TEFs) for these persistent chlorinated organic compounds and their measured concentrations are used to produce the toxic equivalency quotient (TEQ) of a sample. TEF values are partially based on a common mechanism involving binding of the chemical to the aryl hydrocarbon receptor (AhR). Biological methods for the determination of TEQs are based on the assumption that all dioxin-related compounds act through the Ah receptor signal transduction pathway. Based on the biochemical response of CYP1A activation via the AhR, in vitro systems that utilize a reporter gene under transcriptional control of CYP1A have been developed. Several investigations have reported on the success of utilizing biological test systems to detect PCDDs, PCDFs, PCBs in environmental samples. The P450 Human Reporter Gene System assay (EPA Method 4425) utilizes a human hepatoma cell line (HepG2) in which a plasmid containing the human CYP1A1 promoter and 5'-flanking sequences with three xenobiotic responsive elements (XREs) fused to the luciferase reporter gene. The enzyme luciferase is produced in the presence of compounds that bind the XREs, and can be detected by a simple assay that measures relative light units with a luminometer. Method 4425, used by Columbia Analytical Services (CAS), has gained acceptance as a rapid and inexpensive approach for screening solvent extracts of environmental samples of soil, sediment, tissue, and water to detect compounds that activate the AhR. Investigations in the U. S. and Japan comparing the results of 4425 and standard high-resolution GC/MS (HRGC/HRMS) will be reported here. The purpose of making these comparisons is to determine if risk assessments for large dioxin sites both before and after remediation

  10. Gustatory receptor neuron responds to chemically diverse insect repellents in the common malaria mosquito Anopheles quadrimaculatus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Female mosquitoes feed on blood from animal hosts to obtain nutritional resources used for egg production. These contacts facilitate the spread of harmful human diseases. Chemical repellents are used to disrupt mosquito host seeking and blood feeding behaviors; however, little is known about the g...

  11. Chemical and biological diversity of the volatiles of five Artemisia species from far east of Russia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aim of the present study was to investigate the chemical composition and biological activity of essential oils from aerial parts of Artemisia argyi, A. feddei, A. gmelinii, A. manshurica, A. olgensis (Asteraceae). Plants were collected in the Far East region (Primorski Krai) of the Russian Federatio...

  12. Acidification in the Adirondacks: defining the biota in trophic levels of 30 chemically diverse acid-impacted lakes.

    PubMed

    Nierzwicki-Bauer, Sandra A; Boylen, Charles W; Eichler, Lawrence W; Harrison, James P; Sutherland, James W; Shaw, William; Daniels, Robert A; Charles, Donald F; Acker, Frank W; Sullivan, Timothy J; Momen, Bahram; Bukaveckas, Paul

    2010-08-01

    The Adirondack Mountains in New York State have a varied surficial geology and chemically diverse surface waters that are among the most impacted by acid deposition in the U.S. No single Adirondack investigation has been comprehensive in defining the effects of acidification on species diversity, from bacteria through fish, essential for understanding the full impact of acidification on biota. Baseline midsummer chemistry and community composition are presented for a group of chemically diverse Adirondack lakes. Species richness of all trophic levels except bacteria is significantly correlated with lake acid-base chemistry. The loss of taxa observed per unit pH was similar: bacterial genera (2.50), bacterial classes (1.43), phytoplankton (3.97), rotifers (3.56), crustaceans (1.75), macrophytes (3.96), and fish (3.72). Specific pH criteria were applied to the communities to define and identify acid-tolerant (pH<5.0), acid-resistant (pH 5.0-5.6), and acid-sensitive (pH>5.6) species which could serve as indicators. Acid-tolerant and acid-sensitive categories are at end-points along the pH scale, significantly different at P<0.05; the acid-resistant category is the range of pH between these end-points, where community changes continually occur as the ecosystem moves in one direction or another. The biota acid tolerance classification (batc) system described herein provides a clear distinction between the taxonomic groups identified in these subcategories and can be used to evaluate the impact of acid deposition on different trophic levels of biological communities.

  13. Chemically diverse microtubule stabilizing agents initiate distinct mitotic defects and dysregulated expression of key mitotic kinases.

    PubMed

    Rohena, Cristina C; Peng, Jiangnan; Johnson, Tyler A; Crews, Phillip; Mooberry, Susan L

    2013-04-15

    Microtubule stabilizers are some of the most successful drugs used in the treatment of adult solid tumors and yet the molecular events responsible for their antimitotic actions are not well defined. The mitotic events initiated by three structurally and biologically diverse microtubule stabilizers; taccalonolide AJ, laulimalide/fijianolide B and paclitaxel were studied. These microtubule stabilizers cause the formation of aberrant, but structurally distinct mitotic spindles leading to the hypothesis that they differentially affect mitotic signaling. Each microtubule stabilizer initiated different patterns of expression of key mitotic signaling proteins. Taccalonolide AJ causes centrosome separation and disjunction failure to a much greater extent than paclitaxel or laulimalide, which is consistent with the distinct defects in expression and activation of Plk1 and Eg5 caused by each stabilizer. Localization studies revealed that TPX2 and Aurora A are associated with each spindle aster formed by each stabilizer. This suggests a common mechanism of aster formation. However, taccalonolide AJ also causes pericentrin accumulation on every spindle aster. The presence of pericentrin at every spindle aster initiated by taccalonolide AJ might facilitate the maintenance and stability of the highly focused asters formed by this stabilizer. Laulimalide and paclitaxel cause completely different patterns of expression and activation of these proteins, as well as phenotypically different spindle phenotypes. Delineating how diverse microtubule stabilizers affect mitotic signaling pathways could identify key proteins involved in modulating sensitivity and resistance to the antimitotic actions of these compounds.

  14. Chemically Diverse Microtubule Stabilizing Agents Initiate Distinct Mitotic Defects and Dysregulated Expression of Key Mitotic Kinases

    PubMed Central

    Rohena, Cristina C.; Peng, Jiangnan; Johnson, Tyler A.; Crews, Phillip; Mooberry, Susan L.

    2013-01-01

    Microtubule stabilizers are some of the most successful drugs used in the treatment of adult solid tumors and yet the molecular events responsible for their antimitotic actions are not well defined. The mitotic events initiated by three structurally and biologically diverse microtubule stabilizers; taccalonolide AJ, laulimalide/fijianolide B and paclitaxel were studied. These microtubule stabilizers cause the formation of aberrant, but structurally distinct mitotic spindles leading to the hypothesis that they differentially affect mitotic signaling. Each microtubule stabilizer initiated different patterns of expression of key mitotic signaling proteins. Taccalonolide AJ causes centrosome separation and disjunction failure to a much greater extent than paclitaxel or laulimalide, which is consistent with the distinct defects in expression and activation of Plk1 and Eg5 caused by each stabilizer. Localization studies revealed that TPX2 and Aurora A are associated with each spindle aster formed by each stabilizer. This suggests a common mechanism of aster formation. However, taccalonolide AJ also causes pericentrin accumulation on every spindle aster. The presence of pericentrin at every spindle aster initiated by taccalonolide AJ might facilitate the maintenance and stability of the highly focused asters formed by this stabilizer. Laulimalide and paclitaxel cause completely different patterns of expression and activation of these proteins, as well as phenotypically different spindle phenotypes. Delineating how diverse microtubule stabilizers affect mitotic signaling pathways could identify key proteins involved in modulating sensitivity and resistance to the antimitotic actions of these compounds. PMID:23399639

  15. Predicting Toxicities of Diverse Chemical Pesticides in Multiple Avian Species Using Tree-Based QSAR Approaches for Regulatory Purposes.

    PubMed

    Basant, Nikita; Gupta, Shikha; Singh, Kunwar P

    2015-07-27

    A comprehensive safety evaluation of chemicals should require toxicity assessment in both the aquatic and terrestrial test species. Due to the application practices and nature of chemical pesticides, the avian toxicity testing is considered as an essential requirement in the risk assessment process. In this study, tree-based multispecies QSAR (quantitative-structure activity relationship) models were constructed for predicting the avian toxicity of pesticides using a set of nine descriptors derived directly from the chemical structures and following the OECD guidelines. Accordingly, the Bobwhite quail toxicity data was used to construct the QSAR models (SDT, DTF, DTB) and were externally validated using the toxicity data in four other test species (Mallard duck, Ring-necked pheasant, Japanese quail, House sparrow). Prior to the model development, the diversity in the chemical structures and end-point were verified. The external predictive power of the QSAR models was tested through rigorous validation deriving a wide series of statistical checks. Intercorrelation analysis and PCA methods provided information on the association of the molecular descriptors related to MW and topology. The S36 and MW were the most influential descriptors identified by DTF and DTB models. The DTF and DTB performed better than the SDT model and yielded a correlation (R(2)) of 0.945 and 0.966 between the measured and predicted toxicity values in test data array. Both these models also performed well in four other test species (R(2) > 0.918). ChemoTyper was used to identify the substructure alerts responsible for the avian toxicity. The results suggest for the appropriateness of the developed QSAR models to reliably predict the toxicity of pesticides in multiple avian test species and can be useful tools in screening the new chemical pesticides for regulatory purposes.

  16. A three-tier QSAR modeling strategy for estimating eye irritation potential of diverse chemicals in rabbit for regulatory purposes.

    PubMed

    Basant, Nikita; Gupta, Shikha; Singh, Kunwar P

    2016-06-01

    Experimental determination of the eye irritation potential (EIP) of chemicals is not only tedious, time and resource intensive, it involves cruelty to test animals. In this study, we have established a three-tier QSAR modeling strategy for estimating the EIP of chemicals for the use of pharmaceutical industry and regulatory agencies. Accordingly, a qualitative (binary classification: irritating, non-irritating), semi-quantitative (four-category classification), and quantitative (regression) QSAR models employing the SDT, DTF, and DTB methods were developed for predicting the EIP of chemicals in accordance with the OECD guidelines. Structural features of chemicals responsible for eye irritation were extracted and used in QSAR analysis. The external predictive power of the developed QSAR models were evaluated through the internal and external validation procedures recommended in QSAR literature. In test data, the two and four category classification QSAR models (DTF, DTB) rendered accuracy of >93%, while the regression QSAR models (DTF, DTB) yielded correlation (R(2)) of >0.92 between the measured and predicted EIPs. Values of various statistical validation coefficients derived for the test data were above their respective threshold limits (except rm(2) in DTF), thus put a high confidence in this analysis. The applicability domain of the constructed QSAR models were defined using the descriptors range and leverage approaches. The QSAR models in this study performed better than any of the previous studies. The results suggest that the developed QSAR models can reliably predict the EIP of diverse chemicals and can be useful tools for screening of candidate molecules in the drug development process.

  17. Chemical and biological diversity of Bergamot (Citrus bergamia) in relation to environmental factors.

    PubMed

    Statti, Giancarlo A; Conforti, Filomena; Sacchetti, Gianni; Muzzoli, Mariavittoria; Agrimonti, Caterina; Menichini, Francesco

    2004-03-01

    Oil of bergamot is receiving renewed popularity in aromatherapy. The biovariability of Citrus bergamia grown wild in Calabria (Italy) was investigated as far as chemical markers (linalool, linalyl acetate and bergapten) content and antioxidant and antifungal activities of the methanolic extracts. The average content in the markers presents slight variations with the altitude and more evident changes with the latitude of the areas of plant collection.

  18. Molecular diversity of arbuscular mycorrhizal fungi in relation to soil chemical properties and heavy metal contamination.

    PubMed

    Zarei, Mehdi; Hempel, Stefan; Wubet, Tesfaye; Schäfer, Tina; Savaghebi, Gholamreza; Jouzani, Gholamreza Salehi; Nekouei, Mojtaba Khayam; Buscot, François

    2010-08-01

    Abundance and diversity of arbuscular mycorrhizal fungi (AMF) associated with dominant plant species were studied along a transect from highly lead (Pb) and zinc (Zn) polluted to non-polluted soil at the Anguran open pit mine in Iran. Using an established primer set for AMF in the internal transcribed spacer (ITS) region of rDNA, nine different AMF sequence types were distinguished after phylogenetic analyses, showing remarkable differences in their distribution patterns along the transect. With decreasing Pb and Zn concentration, the number of AMF sequence types increased, however one sequence type was only found in the highly contaminated area. Multivariate statistical analysis revealed that further factors than HM soil concentration affect the AMF community at contaminated sites. Specifically, the soils' calcium carbonate equivalent and available P proved to be of importance, which illustrates that field studies on AMF distribution should also consider important environmental factors and their possible interactions.

  19. Rat α-Fetoprotein binding affinities of a large set of structurally diverse chemicals elucidated the relationships between structures and binding affinities.

    PubMed

    Hong, Huixiao; Branham, William S; Dial, Stacey L; Moland, Carrie L; Fang, Hong; Shen, Jie; Perkins, Roger; Sheehan, Daniel; Tong, Weida

    2012-11-19

    Endocrine disrupting chemicals interfere with the endocrine system in animals, including humans, to exert adverse effects. One of the mechanisms of endocrine disruption is through the binding of receptors such as the estrogen receptor (ER) in target cells. The concentration of any chemical in serum is important for its entry into the target cells to bind the receptors. α-Fetoprotein (AFP) is a major transport protein in rodent serum that can bind with estrogens and thus change a chemical's availability for entrance into the target cell. Sequestration of an estrogen in the serum can alter the chemical's potential for disrupting estrogen receptor-mediated responses. To better understand endocrine disruption, we developed a competitive binding assay using rat amniotic fluid, which contains very high levels of AFP, and measured the binding to the rat AFP for 125 structurally diverse chemicals, most of which are known to bind ER. Fifty-three chemicals were able to bind the rat AFP in the assay, while 72 chemicals were determined to be nonbinders. Observations from closely examining the relationship between the binding data and structures of the tested chemicals are rationally explained in a manner consistent with proposed binding regions of rat AFP in the literature. The data reported here represent the largest data set of structurally diverse chemicals tested for rat AFP binding. The data assist in elucidating binding interactions and mechanisms between chemicals and rat AFP and, in turn, assist in the evaluation of the endocrine disrupting potential of chemicals.

  20. Analytical Evaluation of Bit Error Rate Performance of a Free-Space Optical Communication System with Receive Diversity Impaired by Pointing Error

    NASA Astrophysics Data System (ADS)

    Nazrul Islam, A. K. M.; Majumder, S. P.

    2015-06-01

    Analysis is carried out to evaluate the conditional bit error rate conditioned on a given value of pointing error for a Free Space Optical (FSO) link with multiple receivers using Equal Gain Combining (EGC). The probability density function (pdf) of output signal to noise ratio (SNR) is also derived in presence of pointing error with EGC. The average BER of a SISO and SIMO FSO links are analytically evaluated by averaging the conditional BER over the pdf of the output SNR. The BER performance results are evaluated for several values of pointing jitter parameters and number of IM/DD receivers. The results show that, the FSO system suffers significant power penalty due to pointing error and can be reduced by increasing in the number of receivers at a given value of pointing error. The improvement of receiver sensitivity over SISO is about 4 dB and 9 dB when the number of photodetector is 2 and 4 at a BER of 10-10. It is also noticed that, system with receive diversity can tolerate higher value of pointing error at a given BER and transmit power.

  1. Chemical Diversity and Complexity of Scotch Whisky as Revealed by High-Resolution Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Kew, Will; Goodall, Ian; Clarke, David; Uhrín, Dušan

    2017-01-01

    Scotch Whisky is an important product, both culturally and economically. Chemically, Scotch Whisky is a complex mixture, which comprises thousands of compounds, the nature of which are largely unknown. Here, we present a thorough overview of the chemistry of Scotch Whisky as observed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Eighty-five whiskies, representing the majority of Scotch Whisky produced and sold, were analyzed by untargeted high-resolution mass spectrometry. Thousands of chemical formulae were assigned for each sample based on parts-per-billion mass accuracy of FT-ICR MS spectra. For the first time, isotopic fine structure analysis was used to confirm the assignment of high molecular weight CHOS species in Scotch Whisky. The assigned spectra were compared using a number of visualization techniques, including van Krevelen diagrams, double bond equivalence (DBE) plots, as well as heteroatomic compound class distributions. Additionally, multivariate analysis, including PCA and OPLS-DA, was used to interpret the data, with key compounds identified for discriminating between types of whisky (blend or malt) or maturation wood type. FT-ICR MS analysis of Scotch Whisky was shown to be of significant potential in further understanding of the complexity of mature spirit drinks and as a tool for investigating the chemistry of the maturation processes.

  2. Physico-chemical parameters and Ichthyofauna diversity of Arasalar estuary in southeast coast of India

    NASA Astrophysics Data System (ADS)

    Raju, C.; Sridharan, G.; Mariappan, P.; Chelladurai, G.

    2015-01-01

    The physico-chemical changes may have the tendency to accumulate in the various organs of estuarine organisms, especially fish which may in turn enter into the human metabolism through consumption causing serious hazards. Hence, the present study was carried out to dete rmine the physico-chemical characteristics of water and Ichthyofauna in Arasalar estuary in southeast coast of India for the period of 1 year during September 2012-August 2013. The environmental parameters such as, temperature, pH, salinity, DO, silicate, nitrate and phosphate were observed from Department of Zoology, Rajah Serfoji Goverment College, Thanjavur, Tamil Nadu, India. During the period of study, air temperature varied from 28.8 to 35 °C. The surface water temperature also varied from 25 to 31.5 °C. The monthly mean values of hydrogen ion concentration of water varied from 7.1 to 8.2. The salinity of water varied from 5.5 ‰ to 34. Dissolved oxygen in Arasalar estuary was varied from 3.5 to 7.2 mg/l. The total phosphorus varied from 0.29 to 2.15 µg/1. The nitrate varied from 0.47 to 3.75 µg/l. The silicate content varied from 28.25 to 98.74 µg/l. Totally 866 fishes were collected belonging to 4 orders and 5 families. Mystus gulio was found to be the dominant species (25.40 %) in the study area.

  3. An Analytical Framework for Studying Small-Number Effects in Catalytic Reaction Networks: A Probability Generating Function Approach to Chemical Master Equations.

    PubMed

    Nakagawa, Masaki; Togashi, Yuichi

    2016-01-01

    Cell activities primarily depend on chemical reactions, especially those mediated by enzymes, and this has led to these activities being modeled as catalytic reaction networks. Although deterministic ordinary differential equations of concentrations (rate equations) have been widely used for modeling purposes in the field of systems biology, it has been pointed out that these catalytic reaction networks may behave in a way that is qualitatively different from such deterministic representation when the number of molecules for certain chemical species in the system is small. Apart from this, representing these phenomena by simple binary (on/off) systems that omit the quantities would also not be feasible. As recent experiments have revealed the existence of rare chemical species in cells, the importance of being able to model potential small-number phenomena is being recognized. However, most preceding studies were based on numerical simulations, and theoretical frameworks to analyze these phenomena have not been sufficiently developed. Motivated by the small-number issue, this work aimed to develop an analytical framework for the chemical master equation describing the distributional behavior of catalytic reaction networks. For simplicity, we considered networks consisting of two-body catalytic reactions. We used the probability generating function method to obtain the steady-state solutions of the chemical master equation without specifying the parameters. We obtained the time evolution equations of the first- and second-order moments of concentrations, and the steady-state analytical solution of the chemical master equation under certain conditions. These results led to the rank conservation law, the connecting state to the winner-takes-all state, and analysis of 2-molecules M-species systems. A possible interpretation of the theoretical conclusion for actual biochemical pathways is also discussed.

  4. An Analytical Framework for Studying Small-Number Effects in Catalytic Reaction Networks: A Probability Generating Function Approach to Chemical Master Equations

    PubMed Central

    Nakagawa, Masaki; Togashi, Yuichi

    2016-01-01

    Cell activities primarily depend on chemical reactions, especially those mediated by enzymes, and this has led to these activities being modeled as catalytic reaction networks. Although deterministic ordinary differential equations of concentrations (rate equations) have been widely used for modeling purposes in the field of systems biology, it has been pointed out that these catalytic reaction networks may behave in a way that is qualitatively different from such deterministic representation when the number of molecules for certain chemical species in the system is small. Apart from this, representing these phenomena by simple binary (on/off) systems that omit the quantities would also not be feasible. As recent experiments have revealed the existence of rare chemical species in cells, the importance of being able to model potential small-number phenomena is being recognized. However, most preceding studies were based on numerical simulations, and theoretical frameworks to analyze these phenomena have not been sufficiently developed. Motivated by the small-number issue, this work aimed to develop an analytical framework for the chemical master equation describing the distributional behavior of catalytic reaction networks. For simplicity, we considered networks consisting of two-body catalytic reactions. We used the probability generating function method to obtain the steady-state solutions of the chemical master equation without specifying the parameters. We obtained the time evolution equations of the first- and second-order moments of concentrations, and the steady-state analytical solution of the chemical master equation under certain conditions. These results led to the rank conservation law, the connecting state to the winner-takes-all state, and analysis of 2-molecules M-species systems. A possible interpretation of the theoretical conclusion for actual biochemical pathways is also discussed. PMID:27047384

  5. R-chondrite bulk-chemical compositions and diverse oxides: Implications for parent-body processes

    NASA Astrophysics Data System (ADS)

    Isa, Junko; Rubin, Alan E.; Wasson, John T.

    2014-01-01

    R chondrites are among the most oxidized chondrite groups; they also have the highest Δ17O values known in whole-rock meteorites. We analyzed R chondrites (six Antarctic, four hot-desert) by instrumental neutron activation analysis. Data for one of the former and three of the latter show large weathering effects, but the remainder show only moderate scatter and permit us to determine trends and mean compositions for the group. Bulk R-chondrite compositions are similar to those in H and L chondrites, but the concentrations of several volatiles, especially Se and Zn, are higher; the more volatile the element, the higher the enrichment in R chondrites relative to H and L. Petrologic types in R chondrites extend as low as 3.6. We determined olivine compositional distributions and studied opaque oxides in 15 R-chondrite thin sections, including a newly discovered R4 clast in Bencubbin (adding to the diversity of chondritic clasts in this polymict breccia) and an R clast in CM2 Murchison. Opaque oxides in R chondrites include nearly pure magnetite, Al-rich chromite, magnetite-chromite solid solution, nearly pure chromite, and ilmenite. This diverse set of opaque phases reflects differing aqueous-alteration conditions. The least equilibrated R chondrites contain nearly pure magnetite but the spinels in metamorphosed R chondrites contain additional components (e.g., Cr2O3 and Al2O3 and some minor cations). The NiO content in olivine correlates with the magnetite component in magnetite-chromite solid solution in equilibrated R chondrites and is a function of the degree of oxidation. The absence of metallic Fe in A-881988 and LAP 031156 indicates a high degree of oxidation; the relatively low-FeO (Fa35) olivine in these rocks in part reflects the conversion of Fe2+ to Fe3+ and its partitioning into magnetite. Oxidation trends in R chondrites are affected by both aqueous alteration and thermal metamorphism. The differing degrees of oxidation in this group reflect differences

  6. Successions and diversity of humic-reducing microorganisms and their association with physical-chemical parameters during composting.

    PubMed

    Xi, Beidou; Zhao, Xinyu; He, Xiaosong; Huang, Caihong; Tan, Wenbing; Gao, Rutai; Zhang, Hui; Li, Dan

    2016-11-01

    Humic-reducing microorganisms (HRMs) could utilize humic substances (HS) as terminal electron mediator to promote the biodegradation of recalcitrant pollutants. However, the dynamics of HRMs during composting has not been explored. Here, high throughput sequencing technology was applied to investigate the patterns of HRMs during three composting systems. A total of 30 main genera of HRMs were identified in three composts, with Proteobacteria being the largest phylum. HRMs were detected with increased diversity and abundance and distinct patterns during composting, which were significantly associated with dissolved organic carbon, dissolved organic nitrogen and germination index. Regulating key physical-chemical parameters is a process control of HRMs community composition, thus promoting the redox capability of the compost. The redox capability of HRMs were strengthened during composting, suggesting that HRMs of the compost may play an important role on pollutant degradation of the compost or when they are applied to the contaminated soils.

  7. [Chemical diversity of the biological active ingredients of salvia officinalis and some closely related species].

    PubMed

    Máthé, Imre; Hohmann, Judit; Janicsák, Gábor; Nagy, Gábor; Dora, Rédei

    2007-01-01

    Comparative studies on the volatile and non-volatile fractions of 6 species. i.e. Salvia officinalis, S. tomentosa, S. fruticosa, S. candelabrum, S. ringens, S. lavandulifolia of the Section Salvia (Lamiaceae) have been carried out. Both fractions provide the chemical pattern matches to the chemotaxonomic character of Subfamily Nepetoideae in Erdtmanr two subfamiliar system. S. lavandulifolia had the highest essential oil content, followed by S. fruticosa, S. tomentosa, S. officinalis and S. candelabrum. S. ringens contains volatile oil only in traces. The neurotoxin thujone content was the highest in the S. officinalis oils and in that of S. fruticosa. No thujone was detected in S. lavandulifolia. The other species, e.g.: S. tomentosa contain this compound only in moderate concentrations (less than 10%). Among the non-volatile fractions of the plant ingredients the triterpene ursolic and oleanolic acids had the highest concentration in the leaves. Despite some rare cases, ursolic acid dominates the tritepene fraction. Rosmarinic and caffeic acids were measured in similar concentrations, in all species. As the case of S. officinalis shows, these compounds vary significantly in all organs during the vegetation period. Caffeic acid is also ubiquitous in the genus Salvia but as our data suggest it occurs in an order of magnitude lower concentration than rosmarinic acid. The isolation of phenylethanolid martynoside, though obtained in a rather small concentration, is of great chemotaxonomic significance, as this is the first phenylethanolid type glycoside isolated not only from the Salvia genus but also from the entire Subfamily Nepetoideae. As pheylethanolids are rather common and accumulate in significant concentrations in plants of the Subfamily Lamioideae, our opinion that the chemical differences between the two subfamilies are less qualititative than quantitative, is confirmed. This holds true of other chemical markers like monoterpenes, ursolic and oleanolic

  8. Chemical and morphological diversity in wild populations of Mentha longifolia in Israel.

    PubMed

    Segev, Daniel; Nitzan, Nadav; Chaimovitsh, David; Eshel, Amram; Dudai, Nativ

    2012-03-01

    Populations of Mentha longifolia, an endangered species in Israel, were tested for essential oil composition and conservational ability. In 2002-2003, 25 wild populations country-wide were tested, indicating population divergence into two chemotypes. Chemotype A was characterized by high levels of menthone and pulegone, and chemotype B by high levels of piperitenone oxide and piperitone oxide. Chemotype A was more abundant (22 of 25 populations) than chemotype B (11 of 25 populations). However, a chemotype/population interaction was not recorded (P > 0.05). In spring 2003, seven of the 25 wild populations were resampled, propagated, and cultivated at the Newe Ya'ar campus. Then, in 2004, the propagated plants were tested for essential oil composition. The propagated plants maintained the essential oil composition as well as the chemotype-frequency distribution of the original wild population from which they were obtained. Since a chemotype/population interaction was not recorded, and the cultivated plants displayed the wild population essential oil composition, it can be concluded that i) the chemotype diversity is genetically based, and ii) the M. longifolia populations sampled can be horticulturally conserved.

  9. Strawberry Flavor: Diverse Chemical Compositions, a Seasonal Influence, and Effects on Sensory Perception

    PubMed Central

    Schwieterman, Michael L.; Colquhoun, Thomas A.; Jaworski, Elizabeth A.; Bartoshuk, Linda M.; Gilbert, Jessica L.; Tieman, Denise M.; Odabasi, Asli Z.; Moskowitz, Howard R.; Folta, Kevin M.; Klee, Harry J.; Sims, Charles A.; Whitaker, Vance M.; Clark, David G.

    2014-01-01

    Fresh strawberries (Fragaria x ananassa) are valued for their characteristic red color, juicy texture, distinct aroma, and sweet fruity flavor. In this study, genetic and environmentally induced variation is exploited to capture biochemically diverse strawberry fruit for metabolite profiling and consumer rating. Analyses identify fruit attributes influencing hedonics and sensory perception of strawberry fruit using a psychophysics approach. Sweetness intensity, flavor intensity, and texture liking are dependent on sugar concentrations, specific volatile compounds, and fruit firmness, respectively. Overall liking is most greatly influenced by sweetness and strawberry flavor intensity, which are undermined by environmental pressures that reduce sucrose and total volatile content. The volatile profiles among commercial strawberry varieties are complex and distinct, but a list of perceptually impactful compounds from the larger mixture is better defined. Particular esters, terpenes, and furans have the most significant fits to strawberry flavor intensity. In total, thirty-one volatile compounds are found to be significantly correlated to strawberry flavor intensity, only one of them negatively. Further analysis identifies individual volatile compounds that have an enhancing effect on perceived sweetness intensity of fruit independent of sugar content. These findings allow for consumer influence in the breeding of more desirable fruits and vegetables. Also, this approach garners insights into fruit metabolomics, flavor chemistry, and a paradigm for enhancing liking of natural or processed products. PMID:24523895

  10. Actinomycetes from Red Sea Sponges: Sources for Chemical and Phylogenetic Diversity

    PubMed Central

    Abdelmohsen, Usama Ramadan; Yang, Chen; Horn, Hannes; Hajjar, Dina; Ravasi, Timothy; Hentschel, Ute

    2014-01-01

    The diversity of actinomycetes associated with marine sponges collected off Fsar Reef (Saudi Arabia) was investigated in the present study. Forty-seven actinomycetes were cultivated and phylogenetically identified based on 16S rRNA gene sequencing and were assigned to 10 different actinomycete genera. Eight putatively novel species belonging to genera Kocuria, Mycobacterium, Nocardia, and Rhodococcus were identified based on sequence similarity values below 98.2% to other 16S rRNA gene sequences available in the NCBI database. PCR-based screening for biosynthetic genes including type I and type II polyketide synthases (PKS-I, PKS-II) as well as nonribosomal peptide synthetases (NRPS) showed that 20 actinomycete isolates encoded each at least one type of biosynthetic gene. The organic extracts of nine isolates displayed bioactivity against at least one of the test pathogens, which were Gram-positive and Gram-negative bacteria, fungi, human parasites, as well as in a West Nile Virus protease enzymatic assay. These results emphasize that marine sponges are a prolific resource for novel bioactive actinomycetes with potential for drug discovery. PMID:24824024

  11. Actinomycetes from Red Sea sponges: sources for chemical and phylogenetic diversity.

    PubMed

    Abdelmohsen, Usama Ramadan; Yang, Chen; Horn, Hannes; Hajjar, Dina; Ravasi, Timothy; Hentschel, Ute

    2014-05-12

    The diversity of actinomycetes associated with marine sponges collected off Fsar Reef (Saudi Arabia) was investigated in the present study. Forty-seven actinomycetes were cultivated and phylogenetically identified based on 16S rRNA gene sequencing and were assigned to 10 different actinomycete genera. Eight putatively novel species belonging to genera Kocuria, Mycobacterium, Nocardia, and Rhodococcus were identified based on sequence similarity values below 98.2% to other 16S rRNA gene sequences available in the NCBI database. PCR-based screening for biosynthetic genes including type I and type II polyketide synthases (PKS-I, PKS-II) as well as nonribosomal peptide synthetases (NRPS) showed that 20 actinomycete isolates encoded each at least one type of biosynthetic gene. The organic extracts of nine isolates displayed bioactivity against at least one of the test pathogens, which were Gram-positive and Gram-negative bacteria, fungi, human parasites, as well as in a West Nile Virus protease enzymatic assay. These results emphasize that marine sponges are a prolific resource for novel bioactive actinomycetes with potential for drug discovery.

  12. Identification of diverse modulators of central and peripheral circadian clocks by high-throughput chemical screening.

    PubMed

    Chen, Zheng; Yoo, Seung-Hee; Park, Yong-Sung; Kim, Keon-Hee; Wei, Shuguang; Buhr, Ethan; Ye, Zeng-You; Pan, Hui-Lin; Takahashi, Joseph S

    2012-01-03

    The circadian clock coordinates daily oscillations of essential physiological and behavioral processes. Conversely, aberrant clocks with damped amplitude and/or abnormal period have been associated with chronic diseases and aging. To search for small molecules that perturb or enhance circadian rhythms, we conducted a high-throughput screen of approximately 200,000 synthetic compounds using Per2lucSV reporter fibroblast cells and validated 11 independent classes of molecules with Bmal1:luciferase reporter cells as well as with suprachiasmatic nucleus and peripheral tissue explants. Four compounds were found to lengthen the period in both central and peripheral clocks, including three compounds that inhibited casein kinase Iε in vitro and a unique benzodiazepine derivative acting through a non-GABA(A) receptor target. In addition, two compounds acutely induced Per2lucSV reporter bioluminescence, delayed the rhythm, and increased intracellular cAMP levels, but caused rhythm damping. Importantly, five compounds shortened the period of peripheral clocks; among them, four compounds also enhanced the amplitude of central and/or peripheral reporter rhythms. Taken together, these studies highlight diverse activities of drug-like small molecules in manipulating the central and peripheral clocks. These small molecules constitute a toolbox for probing clock regulatory mechanisms and may provide putative lead compounds for treatment of clock-associated diseases.

  13. Chemical and biological diversity in fourteen selections of four Ocimum species.

    PubMed

    Rao, Bhaskaruni R Rajeswara; Kotharia, Sushil K; Rajput, Dharmendra K; Patel, Rajendra P; Darokar, Mahendra P

    2011-11-01

    Biomass, essential oil yield, essential oil composition diversity, and antibacterial and antifungal activities of 14 selections of 4 Ocimum species [Ocimum basilicum L. (selections: T1-T10), O. gratissimum L. (selections: T11-T12), O. tenuiflorum L.f., syn. O. sanctum L. (selection: T13) and O. kilimandscharicum Baker ex. Guerke (selection: T14)] were investigated. O. basilicum selections T9 (methyl chavicol: 87.0%) and T10 {(Z)- and (E)-methyl cinnamate: 69.1%} produced higher biomass (67.8 and 56.7 t/ha) and oil (203.4 and 141.7 kg/ha) yields relative to 8 (T1-T8) linalool (up to 58.9%), or methyl chavicol (up to 61.8%) rich selections. O. gratissimum selection T12 (eugenol: 84.1%, 254.6 kg/ha oil yield) was significantly superior to T11 (62.1% eugenol and 18.4% camphor). O. tenuiflorum (T13, methyl eugenol: 72.5%) and O. kilimandscharicum (T14, camphor: 51.7%) produced 171.7 and 96.2 kg/ha essential oil, respectively. The essential oils exhibited broad spectrum antibacterial (against 5 Gram-positive and 7 Gram-negative bacteria) and antifungal (against 10 fungi) activities. The bacterial species Bacillus subtilis, Staphylococcus aureus, Streptococcus mutans, and Enterococcus faecalis, and the fungal species Epidermophyton floccosum, Microsporum gypseum, and Sporothrix schenckii were more sensitive to the essential oils.

  14. Accelerated structure-based design of chemically diverse allosteric modulators of a muscarinic G protein-coupled receptor

    PubMed Central

    Miao, Yinglong; Goldfeld, Dahlia Anne; Moo, Ee Von; Sexton, Patrick M.; Christopoulos, Arthur; McCammon, J. Andrew; Valant, Celine

    2016-01-01

    Design of ligands that provide receptor selectivity has emerged as a new paradigm for drug discovery of G protein-coupled receptors, and may, for certain families of receptors, only be achieved via identification of chemically diverse allosteric modulators. Here, the extracellular vestibule of the M2 muscarinic acetylcholine receptor (mAChR) is targeted for structure-based design of allosteric modulators. Accelerated molecular dynamics (aMD) simulations were performed to construct structural ensembles that account for the receptor flexibility. Compounds obtained from the National Cancer Institute (NCI) were docked to the receptor ensembles. Retrospective docking of known ligands showed that combining aMD simulations with Glide induced fit docking (IFD) provided much-improved enrichment factors, compared with the Glide virtual screening workflow. Glide IFD was thus applied in receptor ensemble docking, and 38 top-ranked NCI compounds were selected for experimental testing. In [3H]N-methylscopolamine radioligand dissociation assays, approximately half of the 38 lead compounds altered the radioligand dissociation rate, a hallmark of allosteric behavior. In further competition binding experiments, we identified 12 compounds with affinity of ≤30 μM. With final functional experiments on six selected compounds, we confirmed four of them as new negative allosteric modulators (NAMs) and one as positive allosteric modulator of agonist-mediated response at the M2 mAChR. Two of the NAMs showed subtype selectivity without significant effect at the M1 and M3 mAChRs. This study demonstrates an unprecedented successful structure-based approach to identify chemically diverse and selective GPCR allosteric modulators with outstanding potential for further structure-activity relationship studies. PMID:27601651

  15. Genetic and chemical diversity of citron (Citrus medica L.) based on nuclear and cytoplasmic markers and leaf essential oil composition.

    PubMed

    Luro, François; Venturini, Nicolas; Costantino, Gilles; Paolini, Julien; Ollitrault, Patrick; Costa, Jean

    2012-05-01

    Native to southeast Asia, the citron (Citrus medica L.) was the first citrus fruit to be introduced to the Mediterranean area, in the third century BC, and remained its only citrus representative until the tenth century. The citron was used for its aroma - stemming from its essential oils in leaves and fruit peels - and as symbols in the Jewish religion. Subsequently, the cultivation of citron was extended significantly, peaking in the nineteenth century, when its fruits were used in cosmetics and confectioneries. The objective of this study was to examine the genetic diversity of the Mediterranean citron with regard to the multiplication and dissemination practices that were related to its uses. We studied the polymorphisms of 27 nuclear and cytoplasmic genetic markers of 24 citron varieties, preserved in the citrus germplasm of INRA-CIRAD, San Giuliano, France. The composition of leaf essential oils was determined to establish varieties and phylogenic relationships between accessions. Other major citrus species were included in the molecular analysis, which demonstrated the existence of 13 genetically linked citrons, differing from other citrus species, based on low heterozygosity and specific alleles; these citrons were considered true-type citrons, confirmed by their convergent chemical profiles. We also detected a polymorphism in the chloroplastic genome in these 13 citrons, which, when combined with allelic diversity of 2.4 alleles per locus, suggests that multiple citrons were introduced to the Mediterranean area in last 2 millennia. We determined the genetic origin and relationships of several varieties, such as Corsican, which could have arisen from the selfing of Poncire Commun. We noted a higher-than-expected polymorphism rate among Mediterranean citron varieties, likely due to crossfecundation. The chemical leaf oil composition of several economical varieties, such as Corsican, is distinct and can increase the quality of specific agriculture products

  16. The Chemical Diversity of Lantana camara: Analyses of Essential Oil Samples from Cuba, Nepal, and Yemen.

    PubMed

    Satyal, Prabodh; Crouch, Rebecca A; Monzote, Lianet; Cos, Paul; Awadh Ali, Nasser A; Alhaj, Mehdi A; Setzer, William N

    2016-03-01

    The aerial parts of Lantana camara L. were collected from three different geographical locations: Artemisa (Cuba), Biratnagar (Nepal), and Sana'a (Yemen). The essential oils were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry. A cluster analysis of 39 L. camara essential oil compositions revealed eight major chemotypes: β-caryophyllene, germacrene D, ar-curcumene/zingiberene, γ-curcumen-15-al/epi-β-bisabolol, (E)-nerolidol, davanone, eugenol/alloaromadendrene, and carvone. The sample from Cuba falls into the group dominated by (E)-nerolidol, the sample from Nepal is a davanone chemotype, and the sample from Yemen belongs to the β-caryophyllene chemotype. The chemical composition of L. camara oil plays a role in the biological activity; the β-caryophyllene and (E)-nerolidol chemotypes showed antimicrobial and cytotoxic activities.

  17. Phylogenetic and Chemical Diversity of Three Chemotypes of Bloom-Forming Lyngbya Species (Cyanobacteria: Oscillatoriales) from Reefs of Southeastern Florida▿

    PubMed Central

    Sharp, Koty; Arthur, Karen E.; Gu, Liangcai; Ross, Cliff; Harrison, Genelle; Gunasekera, Sarath P.; Meickle, Theresa; Matthew, Susan; Luesch, Hendrik; Thacker, Robert W.; Sherman, David H.; Paul, Valerie J.

    2009-01-01

    The cyanobacterial genus Lyngbya includes free-living, benthic, filamentous cyanobacteria that form periodic nuisance blooms in lagoons, reefs, and estuaries. Lyngbya spp. are prolific producers of biologically active compounds that deter grazers and help blooms persist in the marine environment. Here, our investigations reveal the presence of three distinct Lyngbya species on nearshore reefs in Broward County, FL, sampled in 2006 and 2007. With a combination of morphological measurements, molecular biology techniques, and natural products chemistry, we associated these three Lyngbya species with three distinct Lyngbya chemotypes. One species, identified as Lyngbya cf. confervoides via morphological measurements and 16S rRNA gene sequencing, produces a diverse array of bioactive peptides and depsipeptides. Our results indicate that the other two Lyngbya species produce either microcolins A and B or curacin D and dragonamides C and D. Results from screening for the biosynthetic capacity for curacin production among the three Lyngbya chemotypes in this study correlated that capacity with the presence of curacin D. Our work on these bloom-forming Lyngbya species emphasizes the significant phylogenetic and chemical diversity of the marine cyanobacteria on southern Florida reefs and identifies some of the genetic components of those differences. PMID:19270119

  18. DEVELOPMENT AND VALIDATION OF ANALYTICAL METHODS FOR ENUMERATION OF FECAL INDICATORS AND EMERGING CHEMICAL CONTAMINANTS IN BIOSOLIDS

    EPA Science Inventory

    In 2002 the National Research Council (NRC) issued a report which identified a number of issues regarding biosolids land application practices and pointed out the need for improved and validated analytical techniques for regulated indicator organisms and pathogens. They also call...

  19. Phytoplankton communities of polar regions--Diversity depending on environmental conditions and chemical anthropopressure.

    PubMed

    Kosek, Klaudia; Polkowska, Żaneta; Żyszka, Beata; Lipok, Jacek

    2016-04-15

    The polar regions (Arctic and Antarctic) constitute up to 14% of the biosphere and offer some of the coldest and most arid Earth's environments. Nevertheless several oxygenic phototrophs including some higher plants, mosses, lichens, various algal groups and cyanobacteria, survive that harsh climate and create the base of the trophic relationships in fragile ecosystems of polar environments. Ecosystems in polar regions are characterized by low primary productivity and slow growth rates, therefore they are more vulnerable to disturbance, than those in temperate regions. From this reason, chemical contaminants influencing the growth of photoautotrophic producers might induce serious disorders in the integrity of polar ecosystems. However, for a long time these areas were believed to be free of chemical contamination, and relatively protected from widespread anthropogenic pressure, due their remoteness and extreme climate conditions. Nowadays, there is a growing amount of data that prove that xenobiotics are transported thousands of kilometers by the air and ocean currents and then they are deposed in colder regions and accumulate in many environments, including the habitats of marine and freshwater cyanobacteria. Cyanobacteria (blue green algae), as a natural part of phytoplankton assemblages, are globally distributed, but in high polar ecosystems they represent the dominant primary producers. These microorganisms are continuously exposed to various concentration levels of the compounds that are present in their habitats and act as nourishment or the factors influencing the growth and development of cyanobacteria in other way. The most common group of contaminants in Arctic and Antarctic are persistent organic pollutants (POPs), characterized by durability and resistance to degradation. It is important to determine their concentrations in all phytoplankton species cells and in their environment to get to know the possibility of contaminants to transfer to higher

  20. Human sex hormone-binding globulin binding affinities of 125 structurally diverse chemicals and comparison with their binding to androgen receptor, estrogen receptor, and α-fetoprotein.

    PubMed

    Hong, Huixiao; Branham, William S; Ng, Hui Wen; Moland, Carrie L; Dial, Stacey L; Fang, Hong; Perkins, Roger; Sheehan, Daniel; Tong, Weida

    2015-02-01

    One endocrine disruption mechanism is through binding to nuclear receptors such as the androgen receptor (AR) and estrogen receptor (ER) in target cells. The concentration of a chemical in serum is important for its entry into the target cells to bind the receptors, which is regulated by the serum proteins. Human sex hormone-binding globulin (SHBG) is the major transport protein in serum that can bind androgens and estrogens and thus change a chemical's availability to enter the target cells. Sequestration of an androgen or estrogen in the serum can alter the chemical elicited AR- and ER-mediated responses. To better understand the chemical-induced endocrine activity, we developed a competitive binding assay using human pregnancy plasma and measured the binding to the human SHBG for 125 structurally diverse chemicals, most of which were known to bind AR and ER. Eighty seven chemicals were able to bind the human SHBG in the assay, whereas 38 chemicals were nonbinders. Binding data for human SHBG are compared with that for rat α-fetoprotein, ER and AR. Knowing the binding profiles between serum and nuclear receptors will improve assessment of a chemical's potential for endocrine disruption. The SHBG binding data reported here represent the largest data set of structurally diverse chemicals tested for human SHBG binding. Utilization of the SHBG binding data with AR and ER binding data could enable better evaluation of endocrine disrupting potential of chemicals through AR- and ER-mediated responses since sequestration in serum could be considered.

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

    PubMed

    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.

  2. Impacts of chemical modification on the toxicity of diverse nanocellulose materials to developing zebrafish

    PubMed Central

    Harper, Bryan J.; Clendaniel, Alicea; Sinche, Federico; Way, Daniel; Hughes, Michael; Schardt, Jenna; Simonsen, John; Stefaniak, Aleksandr B.

    2016-01-01

    Cellulose is an abundant and renewable resource currently being investigated for utility in nanomaterial form for various promising applications ranging from medical and pharmaceutical uses to mechanical reinforcement and biofuels. The utility of nanocellulose and wide implementation ensures increasing exposure to humans and the environment as nanocellulose-based technologies advance. Here, we investigate how differences in aspect ratio and changes to surface chemistry, as well as synthesis methods, influence the biocompatibility of nanocellulose materials using the embryonic zebrafish. Investigations into the toxicity of neutral, cationic and anionic surface functionalities revealed that surface chemistry had a minimal influence on the overall toxicity of nanocellulose materials. Higher aspect ratio cellulose nanofibers produced by mechanical homogenization were, in some cases, more toxic than other cellulose-based nanofibers or nanocrystals produced by chemical synthesis methods. Using fluorescently labeled nanocellulose we were able to show that nanocellulose uptake did occur in embryonic zebrafish during development. We conclude that the benign nature of nanocellulose materials makes them an ideal platform to systematically investigate the inherent surface features driving nanomaterial toxicity in order to create safer design principles for engineered nanoparticles. PMID:27468180

  3. Structural Plasticity of Malaria Dihydroorotate Dehydrogenase Allows Selective Binding of Diverse Chemical Scaffolds

    SciTech Connect

    Deng, Xiaoyi; Gujjar, Ramesh; El Mazouni, Farah; Kaminsky, Werner; Malmquist, Nicholas A.; Goldsmith, Elizabeth J.; Rathod, Pradipsinh K.; Phillips, Margaret A.

    2010-01-20

    Malaria remains a major global health burden and current drug therapies are compromised by resistance. Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) was validated as a new drug target through the identification of potent and selective triazolopyrimidine-based DHODH inhibitors with anti-malarial activity in vivo. Here we report x-ray structure determination of PfDHODH bound to three inhibitors from this series, representing the first of the enzyme bound to malaria specific inhibitors. We demonstrate that conformational flexibility results in an unexpected binding mode identifying a new hydrophobic pocket on the enzyme. Importantly this plasticity allows PfDHODH to bind inhibitors from different chemical classes and to accommodate inhibitor modifications during lead optimization, increasing the value of PfDHODH as a drug target. A second discovery, based on small molecule crystallography, is that the triazolopyrimidines populate a resonance form that promotes charge separation. These intrinsic dipoles allow formation of energetically favorable H-bond interactions with the enzyme. The importance of delocalization to binding affinity was supported by site-directed mutagenesis and the demonstration that triazolopyrimidine analogs that lack this intrinsic dipole are inactive. Finally, the PfDHODH-triazolopyrimidine bound structures provide considerable new insight into species-selective inhibitor binding in this enzyme family. Together, these studies will directly impact efforts to exploit PfDHODH for the development of anti-malarial chemotherapy.

  4. Chemical Diversity along the Traverse of the Rover Spirit at Gusev Crater

    NASA Technical Reports Server (NTRS)

    Gellert, R.; Brueckner, J.; Clark, B. C.; Dreibus, G.; d'Uston, C.; Economou, T.; Klingelhoefer, G.; Lugmair, G.; Ming, D. W.; Morris, R. V.; Rieder, R.; Squyres, S. W.; Wanke, H.; Yen, A.; Zipfel, J.

    2006-01-01

    The Alpha-Particle-X-ray Spectrometer (APXS) is part of the in situ payload of the Mars Exploration Rovers. It has determined the chemical composition of soils and rocks along the nearly 6 km long traverse of the rover Spirit. The measuring method a combination of PIXE and XRF using Cm244 sources - allowed the unambiguous identification of elemental compositions with high precision. Besides sample triage and quantification of saltforming elements as indicators for aqueous alteration, the APXS also delivered important constraints to mineralogy intruments (i.e., Mossbauer (MB), MiniTES, Pancam) on minerals and rock types. The mineralogy instruments on the other hand provided constraints on minerals used for APXS normative calculations and, e.g. allowed the attribution of S to sulfate, instead of sulfide or elemental sulfur. This abstract gives an updated overview of the data obtained up to our current rover position on sol 720 at the eastern base of the Columbia Hills. We will emphasize elemental correlations that imply the presence of certain minerals that can not be identified by the MER mineralogy instruments.

  5. Long-term effect on some chemical parameter and microbial diversity in a conifer forest soil

    NASA Astrophysics Data System (ADS)

    Iglesias, T.; Iglesias, M.; Francisco-Álvarez, R.; Ramírez, M.; Fernández-Bermejo, M. C.

    2009-04-01

    Soil microbiota are one of the soil components most affected by wildfires. The data from the present study were obtained from a conifer forest soil at Sierra de Gredos (Ávila, central Spain) twenty years after fire of low-to-moderate intensity. A set of soil characteristics indicated the extent to which the spontaneous recovery of the soil is produced as a result of vegetation regrowth. Ten months after fire a strong increase in soil pH, organic C and N, and exchangeable Ca and K, with respect the control soil. Eighteen years after this fire it was observed a decrease of soil organic C and N, whereas other variables such as pH, exchangeable Ca and K were slightly increased with respect to control soil. Is summe a change in soil microbiota was observed due to wildfire, with a decrease in fungi and bacteria population, Also some changes in microbial community was detected, Key words: Forest Fire, soil microbiology, chemical soil properties

  6. New approaches for studying the chemical diversity of natural resources and the bioactivity of their constituents.

    PubMed

    Wolfender, Jean-Luc; Queiroz, Emerson Ferreira

    2012-01-01

    Natural products (NPs) have historically been an important source of lead molecules in drug discovery. However, the interest that the pharmaceutical industry has had in NPs has declined in part because of the lack of compatibility of traditional natural-product extract libraries with high-throughput screenings and the low hit rate. Furthermore, in contrast to the synthetic libraries, compounds from natural sources are likely to have complex structures which slow down the identification process and contribute to problems related to supply and manufacturing. In this paper, we summarise some of the strategies that are being developed in our research unit to address these issues. On one hand, differential screening strategies were established with the aim of identifying dynamically induced NPs from silent biosynthetic pathways in plants and fungi that had been exposed to different stress situations. On the other hand, high-resolution HPLC techniques were optimised for biological and chemical profiling of crude extracts. This led to an integrated platform for rapid and efficient identification of new drug-leads and biomarkers of interest that were based on miniaturised technological approaches and metabolomics.

  7. Genetic and chemical diversity in seeds of cactus mandacaru (Cereus sp.) from two edaphoclimatic regions contrasting.

    PubMed

    Bevilaqua, Maycon R R; Santana Filho, Arquimedes P; Mangolin, Claudete A; Oliveira, Arildo J B; Machado, Maria De Fátima P S

    2015-01-01

    The purpose of this study was to evaluate the chemical, physiological and genetic differences in seeds of cactus of the Cereus genus (mandacaru) cultivated in the Northeast (Picos, State of Piauí) and Southern (Maringá, State of Paraná) regions of Brazil. Over a period of eight days, temperatures of 25°C and 30°C were equally efficient for the germination of all the seeds. Oleic acid (C18:1) was the most common fatty acid found in the seeds collected in the Southern (41%) and Northeast (45.5%) regions. The analysis of lipases indicated that seeds from Maringá have high mean observed and expected heterozygosities and that seeds from Picos have a higher number of alleles per loci. Therefore, the seeds of mandacaru from the semiarid region of Northeast as well as the seeds from the South (the two contrasting regions of Brazil) are promising with regards to the preservation of the biodiversity in the genome of mandacaru. The low genetic identity between mandacaru seeds from Maringá and Picos at Lipase-5 locus analysis (I = 0.77) suggests that the mandacaru plants from Maringá and Picos may correspond to two species: C. peruvianus and C. jamacaru, respectively.

  8. Chemical Composition and Disruption of Quorum Sensing Signaling in Geographically Diverse United States Propolis

    PubMed Central

    Savka, Michael A.; Dailey, Lucas; Popova, Milena; Mihaylova, Ralitsa; Merritt, Benjamin; Masek, Marissa; Le, Phuong; Nor, Sharifah Radziah Mat; Ahmad, Muhammad; Hudson, André O.; Bankova, Vassya

    2015-01-01

    Propolis or bee glue has been used for centuries for various purposes and is especially important in human health due to many of its biological and pharmacological properties. In this work we showed quorum sensing inhibitory (QSI) activity of ten geographically distinct propolis samples from the United States using the acyl-homoserine lactone- (AHL-) dependent Chromobacterium violaceum strain CV026. Based on GC-MS chemical profiling the propolis samples can be classified into several groups that are as follows: (1) rich in cinnamic acid derivatives, (2) rich in flavonoids, and (3) rich in triterpenes. An in-depth analysis of the propolis from North Carolina led to the isolation and identification of a triterpenic acid that was recently isolated from Hondurian propolis (Central America) and ethyl ether of p-coumaric alcohol not previously identified in bee propolis. QSI activity was also observed in the second group US propolis samples which contained the flavonoid pinocembrin in addition to other flavonoid compounds. The discovery of compounds that are involved in QSI activity has the potential to facilitate studies that may lead to the development of antivirulence therapies that can be complementary and/or alternative treatments against antibiotic resistant bacterial pathogens and/or emerging pathogens that have yet to be identified. PMID:25960752

  9. Impacts of chemical modification on the toxicity of diverse nanocellulose materials to developing zebrafish.

    PubMed

    Harper, Bryan J; Clendaniel, Alicea; Sinche, Federico; Way, Daniel; Hughes, Michael; Schardt, Jenna; Simonsen, John; Stefaniak, Aleksandr B; Harper, Stacey L

    2016-06-01

    Cellulose is an abundant and renewable resource currently being investigated for utility in nanomaterial form for various promising applications ranging from medical and pharmaceutical uses to mechanical reinforcement and biofuels. The utility of nanocellulose and wide implementation ensures increasing exposure to humans and the environment as nanocellulose-based technologies advance. Here, we investigate how differences in aspect ratio and changes to surface chemistry, as well as synthesis methods, influence the biocompatibility of nanocellulose materials using the embryonic zebrafish. Investigations into the toxicity of neutral, cationic and anionic surface functionalities revealed that surface chemistry had a minimal influence on the overall toxicity of nanocellulose materials. Higher aspect ratio cellulose nanofibers produced by mechanical homogenization were, in some cases, more toxic than other cellulose-based nanofibers or nanocrystals produced by chemical synthesis methods. Using fluorescently labeled nanocellulose we were able to show that nanocellulose uptake did occur in embryonic zebrafish during development. We conclude that the benign nature of nanocellulose materials makes them an ideal platform to systematically investigate the inherent surface features driving nanomaterial toxicity in order to create safer design principles for engineered nanoparticles.

  10. Chemical Diversity and Defence Metabolism: How Plants Cope with Pathogens and Ozone Pollution

    PubMed Central

    Iriti, Marcello; Faoro, Franco

    2009-01-01

    Chemical defences represent a main trait of the plant innate immune system. Besides regulating the relationship between plants and their ecosystems, phytochemicals are involved both in resistance against pathogens and in tolerance towards abiotic stresses, such as atmospheric pollution. Plant defence metabolites arise from the main secondary metabolic routes, the phenylpropanoid, the isoprenoid and the alkaloid pathways. In plants, antibiotic compounds can be both preformed (phytoanticipins) and inducible (phytoalexins), the former including saponins, cyanogenic glycosides and glucosinolates. Chronic exposure to tropospheric ozone (O3) stimulates the carbon fluxes from the primary to the secondary metabolic pathways to a great extent, inducing a shift of the available resources in favour of the synthesis of secondary products. In some cases, the plant defence responses against pathogens and environmental pollutants may overlap, leading to the unspecific synthesis of similar molecules, such as phenylpropanoids. Exposure to ozone can also modify the pattern of biogenic volatile organic compounds (BVOC), emitted from plant in response to herbivore feeding, thus altering the tritrophic interaction among plant, phytophagy and their natural enemies. Finally, the synthesis of ethylene and polyamines can be regulated by ozone at level of S-adenosylmethionine (SAM), the biosynthetic precursor of both classes of hormones, which can, therefore, mutually inhibit their own biosynthesis with consequence on plant phenotype. PMID:20111684

  11. Diversity of Ammonia-Oxidizing Archaea and Bacteria Across Physical-Chemical Gradients in San Francisco Bay Estuary Sediments

    NASA Astrophysics Data System (ADS)

    Mosier, A. C.; Francis, C. A.

    2006-12-01

    A combination of recent metagenomic analyses and the cultivation of a novel, ammonia-oxidizing, marine crenarchaeota revealed the first evidence for nitrification within the Archaeal domain. Further genetic and metagenomic studies demonstrated the presence of ammonia-oxidizing crenarchaea in diverse marine and terrestrial environments. These discoveries challenge the currently accepted view of the global nitrogen cycle and validate the need for further research on microbial diversity and function. In particular, it is imperative to reexamine the microbial communities involved in ammonia oxidation in marine and estuarine sediments, where this process plays a pivotal role in the cycling and removal of nitrogen. Using phylogenetic analyses of ammonia monooxygenase subunit A (amoA) gene sequences, we examined the distribution and diversity of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in San Francisco Bay, the largest estuary on the West coast of the United States. The highly impacted bay, encompassing nearly 178,000 km2, effectively connects two estuaries with varying physical-chemical characteristics to the Pacific Ocean. We recovered archaeal and bacterial amoA genes from 11 sites distributed throughout the bay, spanning the northern and southern estuaries and the central region where they connect to the ocean. Richness estimates varied considerably across all sites examined, with archaeal amoA estimates being generally higher than bacterial amoA. Several of the bacterial amoA libraries were represented by fewer than 3 genotypes. Archaeal amoA sequences were phylogenetically diverse and grouped within previously described sediment and soil/sediment clusters. Several sequences were closely related to the only cultivated AOA, Nitrosopumilus maritimus. Both the archaeal and bacterial amoA sequences showed significant regional specificity. Distinct populations exist in the northern and southern estuaries and sequences from the northernmost and southernmost sites

  12. Serological diversity and chemical structures of Campylobacter jejuni low-molecular-weight lipopolysaccharides.

    PubMed Central

    Aspinall, G O; McDonald, A G; Raju, T S; Pang, H; Mills, S D; Kurjanczyk, L A; Penner, J L

    1992-01-01

    Low-Mr lipopolysaccharides (LPS) of Campylobacter jejuni reference strains for serotypes O:1, O:4, O:23, and O:36 were examined through the liberation of core oligosaccharides by mild acid cleavage of the ketosidic linkage of 3-deoxy-D-manno-2-octulosonic acid residues to the lipid A moiety. The liberated oligosaccharides were examined for chemical structure by compositional analysis and methylated linkage analysis in conjunction with fast atom bombardment-mass spectrometry of permethylated oligosaccharide derivatives. The results showed (i) that the LPS contained short oligosaccharide chains of branched nonrepetitive structure, to many of which N-acetylneuraminic acid residues remained attached by 2----3 linkages to 4-linked D-galactose residues in the core structure; (ii) that serotypical differences, which are not readily defined through qualitatively similar compositions, are clearly reflected in variations in linkage types and sequences of sugar residues in the outer core attached to an inner region of invariable structure; but (iii) that the presence or absence of NeuAc residues does not appear to be a basis for serotypical differences. The results also showed that oligosaccharide chains from LPS of serotypes O:1 and O:4 are distinctly different and are distinct again from those of the cross-reacting serotypes O:23 and O:36, between whose core oligosaccharide chains no differences were found. It is concluded that the structurally variable low-Mr LPS from C. jejuni show greater similarities to the lipooligosaccharides from Neisseria spp. than to the highly conserved core regions of Salmonella species. Those strains (serotypes O:23 and O:36) which also furnish high-Mr LPS are unique among gram-negative bacteria in possessing both low-Mr molecules of the Neisseria lipooligosaccharide type and high-Mr LPS of the Salmonella smooth type. Images PMID:1370951

  13. The Diversity of Chemical Composition and the Effects on Stellar Evolution and Planetary Habitability

    NASA Astrophysics Data System (ADS)

    Truitt, Amanda; Young, Patrick A.

    2017-01-01

    For my dissertation under the supervision of Dr. Young, I investigate how stars of different mass and composition evolve, and how stellar evolution impacts the location of the habitable zone around a star. Current research into habitability of exoplanets focuses mostly on the concept of the classical HZ - the range of distances from a star over which liquid water could exist on a planet's surface - determined primarily by the host star's luminosity and spectral characteristics. With the ever-accelerating discovery of new exoplanets, it is imperative to develop a more complete understanding of what factors play a role in creating the “habitable” conditions of a planet. I discuss how stellar evolution is integral to how we define a HZ, and how this work will apply to the search for habitable Earth-like planets in the future.I developed a catalog of stellar evolution models for Sun-like stars with variable compositions; masses range from 0.1-1.2 Msol (spectral types M4-F4) at scaled metallicities of 0.1-1.5 Zsol, and O/Fe, C/Fe, and Mg/Fe values of 0.44-2.28, 0.58-1.72, and 0.54-1.84, respectively. I use a spread in abundance values based on observations of variability in nearby stars. It is important to understand how specific elements (and not just total metallicity) can impact evolutionary lifetime. The time-dependent HZ boundaries have also been calculated for each stellar track. Additionally, I recently created a grid of models for M-dwarfs, and I am currently working to make preliminary estimates of stellar activity vs. age for each representative star in the catalog.My results indicate that to gauge the habitability potential of a given system, both the evolutionary history as well as the detailed chemical characterization of the host star must be considered. This work can be used to assess whether a planet discovered in the HZ of its star has had sufficient time to develop a biosphere capable of producing detectable biosignatures. The catalog is designed

  14. The role of autocatalysis on the chemical diversity of the prebiotic ocean of early Earth

    NASA Astrophysics Data System (ADS)

    Canepa, Carlo

    2016-01-01

    The spontaneous formation of catalytic polypeptides of various lengths in a primordial ocean endowed with a source of amino acids from micrometeorites was investigated and found to be sufficient to induce the transformation of potential substrates under the assumption of a high propensity of the environment to catalyse the formation of the peptide bond. This work aims to include in this picture the effect of autocatalysis, i.e. the ability of a polypeptide with a specific length to promote the formation of the peptide bond. Once the formation of an autocatalytic species is attained, the concentrations of the polypeptides, substrates and products of reaction exhibit a time-dependent rate of formation and undergo a catastrophic change. While in the absence of autocatalysis the concentrations of polypeptides are stationary and the formation of reaction products is limited by the proper frequency λ, autocatalysis induces a steady growth of the concentrations of polypeptides and a 100 - 105-fold increase of reaction products at t = ω-1<0.46 Gyr, with a subsequent linear growth in time according to the law u/z 0 = 1+s(ω-1+t)/z 0, provided the autocatalytic species be active with length fewer than 70 amino acid units. A relationship was found between the catalytic ability of the environment (expressed by the ratio η/ηh of the rate coefficient for peptide bond formation to the corresponding rate coefficient for hydrolysis) and the time of the sharp increase of the concentration of both the polypeptides and their products of transformation. Although the formation of autocatalytic polypeptides is able to rapidly induce a sharp increase in the concentration of both polypeptides and their products of transformation, the crucial formation of the first autocatalytic polypeptides relies on the ability of the environment to promote the formation of the peptide bond. The value of the ratio η/ηh, constrained by the available time for chemical evolution to values bordering the

  15. Analysis on Soil Seed Bank Diversity Characteristics and Its Relation with Soil Physical and Chemical Properties after Substrate Addition

    PubMed Central

    He, Mengxuan; Lv, Lingyue; Li, Hongyuan; Meng, Weiqing; Zhao, Na

    2016-01-01

    Aims Considered as an essential measure in the application of soil seed bank (SSB) projects, the mixing of substrate and surface soil can effectively improve soil condition. This research is aimed at exploring the diversity characteristics of SSBs and the relationships between SSBs and soil properties. Methods Canonical correspondence analysis (CCA) was adopted to describe the ordination of SSBs on soil properties’ gradients; multiple linear regressions were adopted to analyze the relationship between average growth height and soil properties, density and soil properties. Results Experimental groups of mixed substrate (the mixture of organic and inorganic substrates) had high diversity indexes, especially the Shannon-Wiener Index compared with those of single substrate. Meanwhile, a higher number of species and increased density were also noted in those of mixed substrate. The best test group, No.16, had the highest diversity indexes with a Shannon-Wiener of 1.898, Simpson of 0.633 and Pielou of 0.717, and also showed the highest density of 14000 germinants /m2 and 21 species. In addition, an improvement of the soil’s chemical and physical properties was noted when the substrates were mixed. The mixed substrate of turfy soil and perlite could effectively enhance the soil moisture content, whilst a mixed substrate of rice husk carbon and vermiculite could improve the content of available potassium (AK) and phosphorus (AP) and strengthen soil fertility. The germinated plants also reflected obvious regularities of ordination on soil factor gradients. Three distinct cluster groups were presented, of which the first cluster was distributed in an area with a relatively higher content of AK and AP; the second cluster was distributed at places with relatively higher soil moisture content; and the third cluster of plants didn’t show any obvious relationship with soil physical and chemical properties. Through CCA analysis, AK and AP were considered the most important

  16. Analysis of soil samples for chemical warfare agents: Canadian contribution to a multinational round-robin analytical exercise. Memorandum report

    SciTech Connect

    D'Agostino, P.A.; Provost, L.R.; Sawyer, T.W.; Weiss, M.T.

    1990-04-01

    VX and two VX related compounds, diethyl methylphosphonate and bis(2-(diisopropylamino)ethyl) disulfide, were confirmed at the 2 to 40 micrograms/gram level as the principal components in three of four soil samples distributed by Finland as part of a multinational round robin exercise designed to evaluate laboratory methodologies. Several other compounds related to VX, were also identified in extracts of the soil samples. Keywords: Gas chromatography, Canada, Soil samples, Diethyl methylphosphonate, Mass spectrometry, Bis(2-(diisopropylamino)ethyl) disulfide, Bioassay, Defence research establishment suffield(dres), VX, Military chemical agents, International relations, Neuron, Tissue culture, Chemical agent detection.

  17. Integrated sensing platform and method for improved quantitative and selective monitoring of chemical analytes in both liquid and gas phase

    DOEpatents

    Blair, Dianna S.; Frye-Mason, Gregory C.; Butler, Michael A.

    2000-01-01

    By measuring two or more physical parameters of a thin sensing film which are altered when exposed to chemicals, more effective discrimination between chemicals can be achieved. In using more than one sensor, the sensors are preferably integrated on the same substrate so that they may measure the same thin film. Even more preferably, the sensors are provided orthogonal to one another so that they may measure the same portion of the thin film. These provisions reduce problems in discrimination arising from variations in thin films.

  18. Diverse Chemical Zoning Trends in Acapulco Chromites: How Many Sources for the Parental Materials?

    NASA Astrophysics Data System (ADS)

    El Goresy, A.; Janicke, J.

    1995-09-01

    Acapulco is considered to be a link between primitive chondritic meteorites and the differentiated achondrites. Its parent body presumably formed by accretion of material of chondritic compositions at an fO2 that lies between that of H- and enstatite chondrites [1]. The accreted chondritic material was subjected 4.557 Gyr ago to peak temperatures close to 1200 degrees C that lead to partial melting and extensive recrystallization [1, 2]. Seven morphologically different types of graphite with large variations in C- and N-isotopic compositions were recently reported from Acapulco [3, 4]. At least four distinct isotopic reservoirs are required to explain the C- and N-isotopic compositions of these graphites [3, 4]. While the silicate minerals in Acapulco have isotopically heavy N (delta^(15)N = + 15 per mil) chromites were found to be isotopically light (delta^(15)N = _ 75 to _ 82 per mil). Chromite occurs in Acapulco in six different assemblages: (1) as inclusions in silicates, (2) in FeNi, (3) in troilite, (4) with FeNi and troilite, (5) with FeNi and silicates, and (6) with troilite and silicates. It is also rarely present as small idiomorphic inclusions in plagioclase. Chromites in contact with silicates display no chemical zoning for Cr, Al, Ti, Fe, Mg, Mn, or Zn to the silicate borders thus indicating high degree of equilibration with the silicate neighbours. The MgO-contents of chromites in metals and troilites (4.74 to 7.2 %) are relatively lower and their compositional ranges are relatively wider than those in contact with silicates (6.1 to 7.69 %). Zoning profiles of MgO and FeO in chromites in all assemblages are quite flat. Chromites in contact with metals and troilite display a variety of zoning patterns of Cr, Al, Ti, and Zn. All these chromite types , however, depict the same MnO zoning trends with low MnO-contents in their cores (0.96 to 2.14 %) than in their rims to metal or troilite (1.7 to 3.1 %). With few exceptions, the zoning behaviour of Cr, Al

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

    PubMed

    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.

  20. International organization for standardization (ISO) 9000 and chemical agent standard analytical reference material (SASARM) quality system development and implementation. Phase 1. Final report, April 1993-June 1994

    SciTech Connect

    Turley, S.D.

    1994-09-01

    U.S. Army Dugway Proving Ground (DPG) is in the process of developing an International Organization for Standardization (ISO) 9000 quality assurance (QA) system and a Chemical Agent Standard Analytical Reference Material (CASARM) QA program. Phase I of this process consisted of analyzing the current DPG QA system, defining the structure of the new QA system, determine how the ISO 9000 and the CASARM systems will interact, develop the new QA system and implementation plan, and develop the CASARM program and begin implementation. The initial phases of the system design and synthesis met the objectives established for Phase I of this methodology project. Phase II will complete the functional analysis, system design, and prototype implementation. The prototype will be analyzed for weaknesses in operation, personnel and equipment requirements, software, and cost effectiveness. The system will be modified, if needed, and implemented across the Materiel Test Directorate. The final stage of this methodology will be to achieve ISO 9000 registration. International Organization for Standardization(ISO) 9000, Chemical Agent Standard Analytical Reference Material(CASARM), Standardized Quality Assurance(QA), QA/Quality Control(QC).

  1. [Book review] Epiphytic Lichen Diversity and its Dependence on Chemical Site Factors in Differently Elevated Dieback-affected Spruce Stands of the Harz Mountains, by Volker Hesse

    USGS Publications Warehouse

    Bennett, J.P.

    2002-01-01

    Review of: Epiphytic lichen diversity and its dependence on chemical site factors in differently elevated dieback-affected spruce stands of the Harz Mountains. (Dissertationes Botanicae, Band 354). Volker Hesse. 2002. 191 pages, 66 figures, 49 tables, 23x14cm, 390 g. ISBN 978-3-443-64266-2.

  2. Functional diversity of non-lethal effects, chemical camouflage, and variation in fish avoidance in colonizing beetles.

    PubMed

    Resetarits, William J; Pintar, Matthew R

    2016-12-01

    Predators play an extremely important role in natural communities. In freshwater systems, fish can dominate sorting both at the colonization and post-colonization stage. Specifically, for many colonizing species, fish can have non-lethal, direct effects that exceed the lethal direct effects of predation. Functionally diverse fish species with a range of predatory capabilities have previously been observed to elicit functionally equivalent responses on oviposition in tree frogs. We tested this hypothesis of functional equivalence of non-lethal effects for four predatory fish species, using naturally colonizing populations of aquatic beetles. Among taxa other than mosquitoes, and with the exception of the chemically camouflaged pirate perch, Aphredoderus sayanus, we provide the first evidence of variation in colonization or oviposition responses to different fish species. Focusing on total abundance, Fundulus chrysotus, a gape-limited, surface-feeding fish, elicited unique responses among colonizing Hydrophilidae, with the exception of the smallest and most abundant taxa, Paracymus, while Dytiscidae responded similarly to all avoided fish. Neither family responded to A. sayanus. Analysis of species richness and multivariate characterization of the beetle assemblages for the four fish species and controls revealed additional variation among the three avoided species and confirmed that chemical camouflage in A. sayanus results in assemblages essentially identical to fishless controls. The origin of this variation in beetle responses to different fish is unknown, but may involve variation in cue sensitivity, different behavioral algorithms, or differential responses to species-specific fish cues. The identity of fish species occupying aquatic habitats is crucial to understanding community structure, as varying strengths of lethal and non-lethal effects, as well as their interaction, create complex landscapes of predator effects and challenge the notion of functional

  3. Diversity-Oriented Synthesis of Natural-Product-like Libraries Containing a 3-Methylbenzofuran Moiety for the Discovery of New Chemical Elicitors.

    PubMed

    He, Xingrui; Chen, Xia; Lin, Songbo; Mo, Xiaochang; Zhou, Pengyong; Zhang, Zhihao; Lu, Yaoyao; Yang, Yu; Gu, Haining; Shang, Zhicai; Lou, Yonggen; Wu, Jun

    2017-02-01

    Natural products are a major source of biological molecules. The 3-methylfuran scaffold is found in a variety of plant secondary metabolite chemical elicitors that confer host-plant resistance against insect pests. Herein, the diversity-oriented synthesis of a natural-product-like library is reported, in which the 3-methylfuran core is fused in an angular attachment to six common natural product scaffolds-coumarin, chalcone, flavone, flavonol, isoflavone and isoquinolinone. The structural diversity of this library is assessed computationally using cheminformatic analysis. Phenotypic high-throughput screening of β-glucuronidase activity uncovers several hits. Further in vivo screening confirms that these hits can induce resistance in rice to nymphs of the brown planthopper Nilaparvata lugens. This work validates the combination of diversity-oriented synthesis and high-throughput screening of β-glucuronidase activity as a strategy for discovering new chemical elicitors.

  4. An artificially evolved albumin binding module facilitates chemical shift epitope mapping of GA domain interactions with phylogenetically diverse albumins.

    PubMed

    He, Yanan; Chen, Yihong; Rozak, David A; Bryan, Philip N; Orban, John

    2007-07-01

    Protein G-related albumin-binding (GA) modules occur on the surface of numerous Gram-positive bacterial pathogens and their presence may promote bacterial growth and virulence in mammalian hosts. We recently used phage display selection to evolve a GA domain, PSD-1 (phage selected domain-1), which tightly bound phylogenetically diverse albumins. With respect to PSD-1's broad albumin binding specificity, it remained unclear how the evolved binding epitope compared to those of naturally occurring GA domains and whether PSD-1's binding mode was the same for different albumins. We investigate these questions here using chemical shift perturbation measurements of PSD-1 with rabbit serum albumin (RSA) and human serum albumin (HSA) and put the results in the context of previous work on structure and dynamics of GA domains. Combined, these data provide insights into the requirements for broad binding specificity in GA-albumin interactions. Moreover, we note that using the phage-optimized PSD-1 protein significantly diminishes the effects of exchange broadening at the binding interface between GA modules and albumin, presumably through stabilization of a ligand-bound conformation. The employment of artificially evolved domains may be generally useful in NMR structural studies of other protein-protein complexes.

  5. The use of isolated natural products as scaffolds for the generation of chemically diverse screening libraries for drug discovery.

    PubMed

    Barnes, Emma C; Kumar, Rohitesh; Davis, Rohan A

    2016-03-01

    A diverse range of strategies leading to natural product derived or inspired screening libraries aims to increase the number of new chemical entities emerging per year. However, the use of isolated natural products as scaffolds for the semi-synthesis of larger biological screening libraries remains rare. This particular method avoids the time-consuming and resource intensive de novo synthetic strategy for scaffold production, and has become more feasible through improvements to synthetic and isolation methodologies. This Highlight examines the increasing popularity of small- to large-sized screening libraries generated directly from isolated natural products. Several of the examples detailed herein show how this strategy can lead to improvements in not only potency but also other important (and often forgotten) drug discovery parameters such as toxicity, selectivity, lipophilicity and bioavailability. However, there are still improvements to be made to this method, particularly in the choice of the natural product scaffold and the derivatising reagents used. Avoidance of known nuisance compounds or structural alert motifs (e.g. PAINS) that interfere with bioactivity screens, and impact downstream drug development will play a significant role in the future success of this methodology. Incorporation of rational design strategies that take into account the physicochemical parameters (e.g. log P, MW, HBA, HBD) of the final semi-synthetic library analogues will also facilitate the discovery and development of leads and drugs. A multi-pronged approach to drug discovery that incorporates the use of isolated natural product scaffolds for library generation will surely be beneficial.

  6. Automation of the γ-ray spectroscopy counting system at the Dow Chemical Company Analytical Sciences Laboratory

    NASA Astrophysics Data System (ADS)

    Romick, J. D.; Rigot, W. L.; Morabito, P. L.; Quinn, T. J.; Kocher, C. W.; Duke, D. J.

    1994-12-01

    The neutron activation analysis group within the Analytical Sciences Laboratory analyzes 3000-5000 samples annually for a wide variety of analytes. Due to the high sample load, it is imperative that the gamma spectroscopy counting system be automated to maximize the efficiency of the system while ensuring the accuracy of the analyses. Using a Zymark robotic system, Compumotor drives, and DEC-based Canberra/Nuclear Data software we have automated sample changing, detector positioning, and data acquisition. Automation of these functions has resulted in a more consistent counting geometry, minimized crosstalk between samples, and accurate repositioning of the detectors for standardless quantitative analysis. The Zymark robotic system currently controls two detector systems, but is designed to control up to three independent detector systems. Canberra/Nuclear Data software, operating on a Microvax 3100, issues commands to the Zymark controller to change samples when spectral acquisition is complete. Once a new sample is in place, the robot sends a signal to the Microvax to begin data acquisition. Up to 40 samples, with sizes between 1 and 20 ml, can be accommodated using customized sample racks and sample holders. The location of the sample racks relative to the detectors has eliminated noticeable crosstalk between samples in the racks and samples being counted. The two HPGe detectors for each detector system sit on motorized platforms controlled by programmable Compumotor drives. Programmed function keys move the detectors in or out at fixed increments to optimize sample/detector geometry. The high resolution of the stepper motors enables accurate repositioning of detectors so that previously acquired standard spectra can be compared with samples activated and counted under identical conditions but at different times.

  7. First report on development of quantitative interspecies structure-carcinogenicity relationship models and exploring discriminatory features for rodent carcinogenicity of diverse organic chemicals using OECD guidelines.

    PubMed

    Kar, Supratik; Roy, Kunal

    2012-04-01

    Different regulatory agencies in food and drug administration and environmental protection worldwide are employing quantitative structure-activity relationship (QSAR) models to fill the data gaps related with properties of chemicals affecting the environment and human health. Carcinogenicity is a toxicity endpoint of major concern in recent times. Interspecies toxicity correlations may provide a tool for estimating sensitivity towards toxic chemical exposure with known levels of uncertainty for a diversity of wildlife species. In this background, we have developed quantitative interspecies structure-carcinogenicity correlation models for rat and mouse [rodent species according to the Organization for Economic Cooperation and Development (OECD) guidelines] based on the carcinogenic potential of 166 organic chemicals with wide diversity of molecular structures, spanning a large number of chemical classes and biological mechanisms. All the developed models have been assessed according to the OECD principles for the validation of QSAR models. Consensus predictions for carcinogenicity of the individual compounds are presented here for any one species when the data for the other species are available. Informative illustrations of the contributing structural fragments of chemicals which are responsible for specific carcinogenicity endpoints are identified by the developed models. The models have also been used to predict mouse carcinogenicities of 247 organic chemicals (for which rat carcinogenicities are present) and rat carcinogenicities of 150 chemicals (for which mouse carcinogenicities are present). Discriminatory features for rat and mouse carcinogenicity values have also been explored.

  8. Development of preparative and analytical methods of the hop bitter acid oxide fraction and chemical properties of its components.

    PubMed

    Taniguchi, Yoshimasa; Matsukura, Yasuko; Taniguchi, Harumi; Koizumi, Hideki; Katayama, Mikio

    2015-01-01

    The bitter acids in hops (Humulus lupulus L.) and beer, such as α-, β-, and iso-α-acids, are known to affect beer quality and display various physiological effects. However, these compounds readily oxidize, and the effect of the oxides on the properties of beer or their potential health benefits are not well understood. In this study, we developed a simple preparative method for the bitter acid oxide fraction derived from hops and designated the constituents as matured hop bitter acids (MHBA). HPLC-PDA-ESI/HRMS and MS(2) revealed that MHBA are primarily composed of α-acid-derived oxides, which possess a common β-tricarbonyl moiety in their structures similar to α-, β-, and iso-α-acids. We also developed a quantitative analytical method of whole MHBA by HPLC, which showed high precision and reproducibility. Using our newly developed method, the concentration of whole MHBA in several commercial beers was evaluated. Our results will promote the study of bitter acid oxides.

  9. Variations of the stellar initial mass function in semi-analytical models: implications for the mass assembly and the chemical enrichment of galaxies in the GAEA model

    NASA Astrophysics Data System (ADS)

    Fontanot, Fabio; De Lucia, Gabriella; Hirschmann, Michaela; Bruzual, Gustavo; Charlot, Stéphane; Zibetti, Stefano

    2017-02-01

    In this paper, we investigate the implications of the integrated galaxy-wide stellar initial mass function (IGIMF) approach in the framework of the semi-analytical model GAEA (GAlaxy Evolution and Assembly), which features a detailed treatment of chemical enrichment and stellar feedback. The IGIMF provides an analytic description of the dependence of the stellar IMF shape on the rate of star formation in galaxies. We find that our model with a universal IMF predicts a rather flat [α/Fe]-stellar mass relation. The model assuming the IGIMF, instead, is able to reproduce the observed increase of α-enhancement with stellar mass, in agreement with previous studies. This is mainly due to the fact that massive galaxies are characterized by larger star formation rates at high redshift, leading to stronger α-enhancement with respect to low-mass galaxies. At the same time, the IGIMF hypothesis does not affect significantly the trend for shorter star formation time-scales for more massive galaxies. We argue that in the IGIMF scenario the [α/Fe] ratios are good tracers of the highest star formation events. The final stellar masses and mass-to-light ratio of our model massive galaxies are larger than those estimated from the synthetic photometry assuming a universal IMF, providing a self-consistent interpretation of similar recent results, based on dynamical analysis of local early-type galaxies.

  10. Fine Particle Sources and Cardiorespiratory Morbidity: An Application of Chemical Mass Balance and Factor Analytical Source-Apportionment Methods

    PubMed Central

    Sarnat, Jeremy A.; Marmur, Amit; Klein, Mitchel; Kim, Eugene; Russell, Armistead G.; Sarnat, Stefanie E.; Mulholland, James A.; Hopke, Philip K.; Tolbert, Paige E.

    2008-01-01

    Background Interest in the health effects of particulate matter (PM) has focused on identifying sources of PM, including biomass burning, power plants, and gasoline and diesel emissions that may be associated with adverse health risks. Few epidemiologic studies, however, have included source-apportionment estimates in their examinations of PM health effects. We analyzed a time-series of chemically speciated PM measurements in Atlanta, Georgia, and conducted an epidemiologic analysis using data from three distinct source-apportionment methods. Objective The key objective of this analysis was to compare epidemiologic findings generated using both factor analysis and mass balance source-apportionment methods. Methods We analyzed data collected between November 1998 and December 2002 using positive-matrix factorization (PMF), modified chemical mass balance (CMB-LGO), and a tracer approach. Emergency department (ED) visits for a combined cardiovascular (CVD) and respiratory disease (RD) group were assessed as end points. We estimated the risk ratio (RR) associated with same day PM concentrations using Poisson generalized linear models. Results There were significant, positive associations between same-day PM2.5 (PM with aero-dynamic diameter ≤ 2.5 μm) concentrations attributed to mobile sources (RR range, 1.018–1.025) and biomass combustion, primarily prescribed forest burning and residential wood combustion, (RR range, 1.024–1.033) source categories and CVD-related ED visits. Associations between the source categories and RD visits were not significant for all models except sulfate-rich secondary PM2.5 (RR range, 1.012–1.020). Generally, the epidemiologic results were robust to the selection of source-apportionment method, with strong agreement between the RR estimates from the PMF and CMB-LGO models, as well as with results from models using single-species tracers as surrogates of the source-apportioned PM2.5 values. Conclusions Despite differences among the

  11. Green Chemistry Metrics with Special Reference to Green Analytical Chemistry.

    PubMed

    Tobiszewski, Marek; Marć, Mariusz; Gałuszka, Agnieszka; Namieśnik, Jacek

    2015-06-12

    The concept of green chemistry is widely recognized in chemical laboratories. To properly measure an environmental impact of chemical processes, dedicated assessment tools are required. This paper summarizes the current state of knowledge in the field of development of green chemistry and green analytical chemistry metrics. The diverse methods used for evaluation of the greenness of organic synthesis, such as eco-footprint, E-Factor, EATOS, and Eco-Scale are described. Both the well-established and recently developed green analytical chemistry metrics, including NEMI labeling and analytical Eco-scale, are presented. Additionally, this paper focuses on the possibility of the use of multivariate statistics in evaluation of environmental impact of analytical procedures. All the above metrics are compared and discussed in terms of their advantages and disadvantages. The current needs and future perspectives in green chemistry metrics are also discussed.

  12. Analytical chemical kinetic investigation of the effects of oxygen, hydrogen, and hydroxyl radicals on hydrogen-air combustion

    NASA Technical Reports Server (NTRS)

    Carson, G. T., Jr.

    1974-01-01

    Quantitative values were computed which show the effects of the presence of small amounts of oxygen, hydrogen, and hydroxyl radicals on the finite-rate chemical kinetics of premixed hydrogen-air mixtures undergoing isobaric autoignition and combustion. The free radicals were considered to be initially present in hydrogen-air mixtures at equivalence ratios of 0.2, 0.6, 1.0, and 1.2. Initial mixture temperatures were 1100 K, 1200 K, and 1500 K, and pressures were 0.5, 1.0, 2.0, and 4.0 atm. Of the radicals investigated, atomic oxygen was found to be the most effective for reducing induction time, defined as the time to 5 percent of the total combustion temperature rise. The reaction time, the time between 5 percent and 95 percent of the temperature rise, is not decreased by the presence of free radicals in the initial hydrogen-air mixture. Fuel additives which yield free radicals might be used to effect a compact supersonic combustor design for efficient operation in an otherwise reaction-limited combustion regime.

  13. Localization and chemical forms of cadmium in plant samples by combining analytical electron microscopy and X-ray spectromicroscopy

    NASA Astrophysics Data System (ADS)

    Isaure, Marie-Pierre; Fayard, Barbara; Sarret, Géraldine; Pairis, Sébastien; Bourguignon, Jacques

    2006-12-01

    Cadmium (Cd) is a metal of high toxicity for plants. Resolving its distribution and speciation in plants is essential for understanding the mechanisms involved in Cd tolerance, trafficking and accumulation. The model plant Arabidopsis thaliana was exposed to cadmium under controlled conditions. Elemental distributions in the roots and in the leaves were determined using scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDX), and synchrotron-based micro X-ray fluorescence (μ-XRF), which offers a better sensitivity. The chemical form(s) of cadmium was investigated using Cd L III-edge (3538 eV) micro X-ray absorption near edge structure (μ-XANES) spectroscopy. Plant μ-XANES spectra were fitted by linear combination of Cd reference spectra. Biological sample preparation and conditioning is a critical point because of possible artifacts. In this work we compared freeze-dried samples analyzed at ambient temperature and frozen hydrated samples analyzed at -170 °C. Our results suggest that in the roots Cd is localized in vascular bundles, and coordinated to S ligands. In the leaves, trichomes (epidermal hairs) represent the main compartment of Cd accumulation. In these specialized cells, μ-XANES results show that the majority of Cd is bound to O/N ligands likely provided by the cell wall, and a minor fraction could be bound to S-containing ligands. No significant difference in Cd speciation was observed between freeze-dried and frozen hydrated samples. This work illustrates the interest and the sensitivity of Cd L III-edge XANES spectroscopy, which is applied here for the first time to plant samples. Combining μ-XRF and Cd L III-edge μ-XANES spectroscopy offers promising tools to study Cd storage and trafficking mechanisms in plants and other biological samples.

  14. DEVELOPMENT OF ANALYTICAL METHODS FOR THE QUANTIFICATION OF THE CHEMICAL FORMS OF MERCURY AND OTHER TARGET POLLUTANTS IN COAL-FIRED BOILER FLUE GAS

    SciTech Connect

    Terence J. McManus, Ph.D.

    1999-06-30

    . (ATS) as a secondary DOE contractor on this project, assessed the sampling and analytical plans and the emission reports of the five primary contractors to determine how successful the contractors were in satisfying their defined objectives. ATS identified difficulties and inconsistencies in a number of sampling and analytical methodologies in these studies. In particular there was uncertainty as to the validity of the sampling and analytical methods used to differentiate the chemical forms of mercury observed in coal flue gas. Considering the differences in the mercury species with regard to human toxicity, the rate of transport through the ecosystem and the design variations in possible emission control schemes, DOE sought an accurate and reliable means to identify and quantify the various mercury compounds emitted by coal-fired utility boilers. ATS, as a contractor for DOE, completed both bench- and pilot-scale studies on various mercury speciation methods. The final validation of the modified Ontario-Hydro Method, its acceptance by DOE and submission of the method for adoption by ASTM was a direct result of these studies carried out in collaboration with the University of North Dakota's Energy and Environmental Research Center (UNDEERC). This report presents the results from studies carried out at ATS in the development of analytical methods to identify and quantify various chemical species, particularly those of mercury, in coal derived flue gas. Laboratory- and pilot-scale studies, not only on mercury species, but also on other inorganics and organics present in coal combustion flue gas are reported.

  15. Validating Analytical Methods

    ERIC Educational Resources Information Center

    Ember, Lois R.

    1977-01-01

    The procedures utilized by the Association of Official Analytical Chemists (AOAC) to develop, evaluate, and validate analytical methods for the analysis of chemical pollutants are detailed. Methods validated by AOAC are used by the EPA and FDA in their enforcement programs and are granted preferential treatment by the courts. (BT)

  16. Evaluation of laser diode thermal desorption (LDTD) coupled with tandem mass spectrometry (MS/MS) for support of in vitro drug discovery assays: increasing scope, robustness and throughput of the LDTD technique for use with chemically diverse compound libraries.

    PubMed

    Beattie, Iain; Smith, Aaron; Weston, Daniel J; White, Peter; Szwandt, Simon; Sealey, Laura

    2012-02-05

    Within the drug discovery environment, the key process in optimising the chemistry of a structural series toward a potential drug candidate is the design, make and test cycle, in which the primary screens consist of a number of in vitro assays, including metabolic stability, cytochrome P450 inhibition, and time-dependent inhibition assays. These assays are often carried out using multiple drug compounds with chemically diverse structural features, often in a 96 well-plate format for maximum time-efficiency, and are supported using rapid liquid chromatographic (LC) sample introduction with a tandem mass spectrometry (MS/MS) selected reaction monitoring (SRM) endpoint, taking around 6.5 h per plate. To provide a faster time-to-decision at this critical point, there exists a requirement for higher sample throughput and a robust, well-characterized analytical alternative. This paper presents a detailed evaluation of laser diode thermal desorption (LDTD), a relatively new ambient sample ionization technique, for compound screening assays. By systematic modification of typical LDTD instrumentation and workflow, and providing deeper understanding around overcoming a number of key issues, this work establishes LDTD as a practical, rapid alternative to conventional LC-MS/MS in drug discovery, without need for extensive sample preparation or expensive, scope-limiting internal standards. Analysis of both the five and three cytochrome P450 competitive inhibition assay samples by LDTD gave improved sample throughput (0.75 h per plate) and provided comparable data quality as the IC₅₀ values obtained were within 3 fold of those calculated from the LC-MS/MS data. Additionally when applied generically to a chemically diverse library of over 250 proprietary compounds from the AstraZeneca design, make and test cycle, LDTD demonstrated a success rate of 98%.

  17. Physiological and chemical response of lichens transplanted in and around an industrial area of south Italy: relationship with the lichen diversity.

    PubMed

    Paoli, Luca; Pisani, Tommaso; Guttová, Anna; Sardella, Giovanni; Loppi, Stefano

    2011-05-01

    The lichen Evernia prunastri (L.) Ach. has been exposed for 3 months in and around an industrial area of Mediterranean Italy for monitoring physiological (photosynthetic efficiency, membrane lipids peroxidation and cell membrane integrity) and chemical (bioaccumulation of the heavy metals Cr, Ni, Pb, V and Zn) effects and investigate the consistency with the environmental quality status depicted by the diversity of epiphytic lichens (index of lichen diversity (ILD)). The results showed that thalli transplanted close to the industrial area exhibited early stress symptoms, as revealed by the increase in electrical conductivity indicating a damage endured by lichen cell membranes. The electrical conductivity was inversely correlated with the diversity of epiphytic lichens recorded at the same sites. The ILD negatively correlated also with membrane lipid peroxidation and the rate of accumulation of Pb, V and Zn. Reciprocal correlations found among trace elements pinpointed vehicular traffic and metal processing in the industrial area as main sources. The damage endured by cell membranes was the best physiological indicator consistent with the air quality status depicted by the diversity of epiphytic lichens.

  18. Metabolic profiling of Lolium perenne shows functional integration of metabolic responses to diverse subtoxic conditions of chemical stress.

    PubMed

    Serra, Anne-Antonella; Couée, Ivan; Renault, David; Gouesbet, Gwenola; Sulmon, Cécile

    2015-04-01

    Plant communities are confronted with a great variety of environmental chemical stresses. Characterization of chemical stress in higher plants has often been focused on single or closely related stressors under acute exposure, or restricted to a selective number of molecular targets. In order to understand plant functioning under chemical stress conditions close to environmental pollution conditions, the C3 grass Lolium perenne was subjected to a panel of different chemical stressors (pesticide, pesticide degradation compound, polycyclic aromatic hydrocarbon, and heavy metal) under conditions of seed-level or root-level subtoxic exposure. Physiological and metabolic profiling analysis on roots and shoots revealed that all of these subtoxic chemical stresses resulted in discrete physiological perturbations and complex metabolic shifts. These metabolic shifts involved stressor-specific effects, indicating multilevel mechanisms of action, such as the effects of glyphosate and its degradation product aminomethylphosphonic acid on quinate levels. They also involved major generic effects that linked all of the subtoxic chemical stresses with major modifications of nitrogen metabolism, especially affecting asparagine, and of photorespiration, especially affecting alanine and glycerate. Stress-related physiological effects and metabolic adjustments were shown to be integrated through a complex network of metabolic correlations converging on Asn, Leu, Ser, and glucose-6-phosphate, which could potentially be modulated by differential dynamics and interconversion of soluble sugars (sucrose, trehalose, fructose, and glucose). Underlying metabolic, regulatory, and signalling mechanisms linking these subtoxic chemical stresses with a generic impact on nitrogen metabolism and photorespiration are discussed in relation to carbohydrate and low-energy sensing.

  19. SAM Chemical Methods Query

    EPA Pesticide Factsheets

    Laboratories measuring target chemical, radiochemical, pathogens, and biotoxin analytes in environmental samples can use this online query tool to identify analytical methods in EPA's Selected Analytical Methods for Environmental Remediation and Recovery

  20. Does the Chemical Diversity of the Order Haplosclerida (Phylum Porifera: Class Demospongia) Fit with Current Taxonomic Classification?

    PubMed

    Tribalat, Marie-Aude; Marra, Maria V; McCormack, Grace P; Thomas, Olivier P

    2016-06-01

    Sponges and their associated microbiota are well known to produce a large diversity of natural products, also called specialized metabolites. In addition to their potential use in the pharmaceutical industry, these rather species-specific compounds may help in the classification of some particular sponge groups. We review herein compounds isolated from haplosclerid sponges (Class Demospongia, Order Haplosclerida) in order to help in the revision of this large group of marine invertebrates. We focus only on 3-alkylpyridine derivatives and polyacetylenic compounds, as these two groups of natural products are characteristic of haplosclerid species and are highly diverse. A close collaboration between chemists and biologists is required in order to fully apply chemotaxonomical approaches, and whenever possible biological data should include morphological and molecular data and some insight into their microbial abundance.

  1. Nuclear analytical chemistry

    SciTech Connect

    Brune, D.; Forkman, B.; Persson, B.

    1984-01-01

    This book covers the general theories and techniques of nuclear chemical analysis, directed at applications in analytical chemistry, nuclear medicine, radiophysics, agriculture, environmental sciences, geological exploration, industrial process control, etc. The main principles of nuclear physics and nuclear detection on which the analysis is based are briefly outlined. An attempt is made to emphasise the fundamentals of activation analysis, detection and activation methods, as well as their applications. The book provides guidance in analytical chemistry, agriculture, environmental and biomedical sciences, etc. The contents include: the nuclear periodic system; nuclear decay; nuclear reactions; nuclear radiation sources; interaction of radiation with matter; principles of radiation detectors; nuclear electronics; statistical methods and spectral analysis; methods of radiation detection; neutron activation analysis; charged particle activation analysis; photon activation analysis; sample preparation and chemical separation; nuclear chemical analysis in biological and medical research; the use of nuclear chemical analysis in the field of criminology; nuclear chemical analysis in environmental sciences, geology and mineral exploration; and radiation protection.

  2. Diversity and chemical defense role of culturable non-actinobacterial bacteria isolated from the South China Sea gorgonians.

    PubMed

    Peng, Jiang; Zhang, Xiaoyong; Xu, Xinya; He, Fei; Qi, Shuhua

    2013-04-01

    The diversity of culturable non-actinobacterial (NA) bacteria associated with four species of South China Sea gorgonians was investigated using culture-dependent methods followed by analysis of the bacterial 16S rDNA sequence. A total of 76 bacterial isolates were recovered and identified, which belonged to 21 species of 7 genera, and Bacillus was the most diverse genus. Fifty-one percent of the 76 isolates displayed antibacterial activities, and most of them belonged to the Bacillus genus. From the culture broth of gorgonian-associated Bacillus methylotrophicus SCSGAB0092 isolated from gorgonian Melitodes squamata, 11 antimicrobial lipopeptides including seven surfactins and four iturins were obtained. These results imply that Bacillus strains associated with gorgonians play roles in coral defense mechanisms through producing antimicrobial substances. This study, for the first time, compares the diversity of culturable NA bacterial communities among four species of South China Sea gorgonians and investigates the secondary metabolites of gorgonian-associated B. methylotrophicus SCSGAB0092.

  3. Development and validation of regression-based QSAR models for quantification of contributions of molecular fragments to skin sensitization potency of diverse organic chemicals.

    PubMed

    Nandy, A; Kar, S; Roy, K

    2013-01-01

    In our present work, we have developed regression-based QSAR models for skin sensitization potential of 51 diverse organic chemicals. The objective behind the present work is to determine the influence of different molecular features on the skin sensitizing potential of chemicals. Among several models developed, the two best ones are discussed to unveil specific information regarding the contribution of different structural and physicochemical features towards the property of skin sensitization. The QSAR models suggested that aromatic compounds are more skin sensitizing than aliphatic ones, but in the case of carbonyl compounds, aliphatic ones are more skin sensitizing than aromatic ones. Other descriptors such as LUMO and <2-Atype_H-47> signify the importance of the electrophilic and hydrophilic character respectively of the molecules for showing skin sensitizing property. Another two descriptors, and (3)χC also exert significant contributions towards the skin sensitization potential of the chemicals. Further, it is observed that the nitrogen atoms (nN), triple bonds (nTB) and also the fragment Al-C(=X)-Al (Atype_C38) are responsible for skin sensitizing property. All the above information provides additional support for further research involving identification of the skin sensitization potential of new chemicals.

  4. Chemical diversity among fine-grained soils at Gale (Mars): a chemical transition as the rover is approaching the Bagnold Dunes?

    NASA Astrophysics Data System (ADS)

    Cousin, Agnès; Forni, Olivier; Meslin, Pierre-Yves; Schroeder, Susanne; Gasnault, Olivier; Bridges, Nathan; Ehlmann, Bethany; Maurice, Sylvestre; Wiens, Roger

    2016-04-01

    The ChemCam instrument has the capability to study the chemical composition of soils at a sub-millimeter scale, thus providing an unpreceedented spatial resolution for their study. More than 300 soils have been sampled so far with ChemCam and these targets are analyzed frequently in order to monitor any change in composition along the traverse. Detailed chemical analysis as a function of grain size is of great importance in order to better constrain soils formation. Curiosity is approaching the Bagnold Dunes, the first active dune field accessible for in-situ analyses. One of the main goals is to determine or constrain the dune material chemistry as well as its provenance. This study is focusing on recent soils analyzed when ap-proaching the dunes, for a comparison with previous soil targets, and with dunes specifically. Chemical composition of fine-grained soils as we approach the Bagnold Dunes has been compared with previous fine-grained soils analyzed along the traverse. These new soils have an average sum of oxides that is significantly higher than what has been previously analyzed. This would suggest that these soils are less hydrated and probably less altered than previous ones.An enrichment in SiO2, FeO and alkali is also observed in these new fine-grained soils, which could be related to a contamination by local rocks due to erosion. Some coarser grains could correspond to an olivine component. This analysis is on-going and will be detailed as the dedicated Bagnold Dunes campaign starts. We will also report in the hydratation level of the dunes.

  5. Chemical diversity of biologically active metabolites in the sclerotia of Inonotus obliquus and submerged culture strategies for up-regulating their production.

    PubMed

    Zheng, Weifa; Miao, Kangjie; Liu, Yubing; Zhao, Yanxia; Zhang, Meimei; Pan, Shenyuan; Dai, Yucheng

    2010-07-01

    Inonotus obliquus (Fr.) Pilat is a white rot fungus belonging to the family Hymenochaetaceae in the Basidiomycota. In nature, this fungus rarely forms a fruiting body but usually an irregular shape of sclerotial conk called 'Chaga'. Characteristically, I. obliquus produces massive melanins released to the surface of Chaga. As early as in the sixteenth century, Chaga was used as an effective folk medicine in Russia and Northern Europe to treat several human malicious tumors and other diseases in the absence of any unacceptable toxic side effects. Chemical investigations show that I. obliquus produces a diverse range of secondary metabolites including phenolic compounds, melanins, and lanostane-type triterpenoids. Among these are the active components for antioxidant, antitumoral, and antiviral activities and for improving human immunity against infection of pathogenic microbes. Geographically, however, this fungus is restricted to very cold habitats and grows very slowly, suggesting that Chaga is not a reliable source of these bioactive compounds. Attempts for culturing this fungus axenically all resulted in a reduced production of bioactive metabolites. This review examines the current progress in the discovery of chemical diversity of Chaga and their biological activities and the strategies to modulate the expression of desired pathways to diversify and up-regulate the production of bioactive metabolites by the fungus grown in submerged cultures for possible drug discovery.

  6. The fruit cuticles of wild tomato species exhibit architectural and chemical diversity, providing a new model for studying the evolution of cuticle function.

    PubMed

    Yeats, Trevor H; Buda, Gregory J; Wang, Zhonghua; Chehanovsky, Noam; Moyle, Leonie C; Jetter, Reinhard; Schaffer, Arthur A; Rose, Jocelyn K C

    2012-02-01

    The cuticle covers the aerial epidermis of land plants and plays a primary role in water regulation and protection from external stresses. Remarkable species diversity in the structure and composition of its components, cutin and wax, have been catalogued, but few functional or genetic correlations have emerged. Tomato (Solanum lycopersicum) is part of a complex of closely related wild species endemic to the northern Andes and the Galapagos Islands (Solanum Sect. Lycopersicon). Although sharing an ancestor <7 million years ago, these species are found in diverse environments and are subject to unique selective pressures. Furthermore, they are genetically tractable, since they can be crossed with S. lycopersicum, which has a sequenced genome. With the aim of evaluating the relationships between evolution, structure and function of the cuticle, we characterized the morphological and chemical diversity of fruit cuticles of seven species from Solanum Sect. Lycopersicon. Striking differences in cuticular architecture and quantities of cutin and waxes were observed, with the wax coverage of wild species exceeding that of S. lycopersicum by up to seven fold. Wax composition varied in the occurrence of wax esters and triterpenoid isomers. Using a Solanum habrochaites introgression line population, we mapped triterpenoid differences to a genomic region that includes two S. lycopersicum triterpene synthases. Based on known metabolic pathways for acyl wax compounds, hypotheses are discussed to explain the appearance of wax esters with atypical chain lengths. These results establish a model system for understanding the ecological and evolutionary functional genomics of plant cuticles.

  7. The fruit cuticles of wild tomato species exhibit architectural and chemical diversity, providing a new model for studying the evolution of cuticle function

    PubMed Central

    Yeats, Trevor H.; Buda, Gregory J.; Wang, Zhonghua; Chehanovsky, Noam; Moyle, Leonie C.; Jetter, Reinhard; Schaffer, Arthur A.; Rose, Jocelyn K.C.

    2013-01-01

    Summary The cuticle covers the aerial epidermis of land plants and plays a primary role in water regulation and protection from external stresses. Remarkable species diversity in the structure and composition of its components, cutin and wax, have been catalogued, but few functional or genetic correlations have emerged. Tomato (Solanum lycopersicum) is part of a complex of closely related wild species endemic to the northern Andes and the Galapagos Islands (Solanum Sect. Lycopersicon). Although sharing an ancestor less than seven million years ago, these species are found in diverse environments and are subject to unique selective pressures. Furthermore, they are genetically tractable, since they can be crossed with S. lycopersicum, which has a sequenced genome. With the aim of evaluating the relationships between evolution, structure and function of the cuticle, we characterized the morphological and chemical diversity of fruit cuticles of seven species from Solanum Sect. Lycopersicon. Striking differences in cuticular architecture and quantities of cutin and waxes were observed, with wild species wax coverage exceeding that of S. lycopersicum by up to seven fold. Wax composition varied in the occurrence of wax esters and triterpenoid isomers. Using a S. habrochaites introgression line population, we mapped triterpenoid differences to a genomic region that includes two S. lycopersicum triterpene synthases. Based on known metabolic pathways for acyl wax compounds, hypotheses are discussed to explain the appearance of wax esters with atypical chain lengths. These results establish a model system for understanding the ecological and evolutionary functional genomics of plant cuticles. PMID:22007785

  8. QSAR prediction of estrogen activity for a large set of diverse chemicals under the guidance of OECD principles.

    PubMed

    Liu, Huanxiang; Papa, Ester; Gramatica, Paola

    2006-11-01

    A large number of environmental chemicals, known as endocrine-disrupting chemicals, are suspected of disrupting endocrine functions by mimicking or antagonizing natural hormones, and such chemicals may pose a serious threat to the health of humans and wildlife. They are thought to act through a variety of mechanisms, mainly estrogen-receptor-mediated mechanisms of toxicity. However, it is practically impossible to perform thorough toxicological tests on all potential xenoestrogens, and thus, the quantitative structure--activity relationship (QSAR) provides a promising method for the estimation of a compound's estrogenic activity. Here, QSAR models of the estrogen receptor binding affinity of a large data set of heterogeneous chemicals have been built using theoretical molecular descriptors, giving full consideration to the new OECD principles in regulation for QSAR acceptability, during model construction and assessment. An unambiguous multiple linear regression (MLR) algorithm was used to build the models, and model predictive ability was validated by both internal and external validation. The applicability domain was checked by the leverage approach to verify prediction reliability. The results obtained using several validation paths indicate that the proposed QSAR model is robust and satisfactory, and can provide a feasible and practical tool for the rapid screening of the estrogen activity of organic compounds.

  9. Fungal Endophytes of Alpinia officinarum Rhizomes: Insights on Diversity and Variation across Growth Years, Growth Sites, and the Inner Active Chemical Concentration

    PubMed Central

    Shubin, Li; Juan, Huang; RenChao, Zhou; ShiRu, Xu; YuanXiao, Jin

    2014-01-01

    In the present study, the terminal-restriction fragment length polymorphism (T-RFLP) technique, combined with the use of a clone library, was applied to assess the baseline diversity of fungal endophyte communities associated with rhizomes of Alpinia officinarum Hance, a medicinal plant with a long history of use. A total of 46 distinct T-RFLP fragment peaks were detected using HhaI or MspI mono-digestion-targeted, amplified fungal rDNA ITS sequences from A. officinarum rhizomes. Cloning and sequencing of representative sequences resulted in the detection of members of 10 fungal genera: Pestalotiopsis, Sebacina, Penicillium, Marasmius, Fusarium, Exserohilum, Mycoleptodiscus, Colletotrichum, Meyerozyma, and Scopulariopsis. The T-RFLP profiles revealed an influence of growth year of the host plant on fungal endophyte communities in rhizomes of this plant species; whereas, the geographic location where A. officinarum was grown contributed to only limited variation in the fungal endophyte communities of the host tissue. Furthermore, non-metric multidimensional scaling (NMDS) analysis across all of the rhizome samples showed that the fungal endophyte community assemblages in the rhizome samples could be grouped according to the presence of two types of active indicator chemicals: total volatile oils and galangin. Our present results, for the first time, address a diverse fungal endophyte community is able to internally colonize the rhizome tissue of A. officinarum. The diversity of the fungal endophytes found in the A. officinarum rhizome appeared to be closely correlated with the accumulation of active chemicals in the host plant tissue. The present study also provides the first systematic overview of the fungal endophyte communities in plant rhizome tissue using a culture-independent method. PMID:25536070

  10. Evolution of the habitable zone of low-mass stars. Detailed stellar models and analytical relationships for different masses and chemical compositions

    NASA Astrophysics Data System (ADS)

    Valle, G.; Dell'Omodarme, M.; Prada Moroni, P. G.; Degl'Innocenti, S.

    2014-07-01

    Context. The habitability of an exoplanet is assessed by determining the times at which its orbit lies in the circumstellar habitable zone (HZ). This zone evolves with time following the stellar luminosity variation, which means that the time spent in the HZ depends on the evolution of the host star. Aims: We study the temporal evolution of the HZ of low-mass stars - only due to stellar evolution - and evaluate the related uncertainties. These uncertainties are then compared with those due to the adoption of different climate models. Methods: We computed stellar evolutionary tracks from the pre-main sequence phase to the helium flash at the red-giant branch tip for stars with masses in the range [0.70-1.10] M⊙, metallicity Z in the range [0.005-0.04], and various initial helium contents. By adopting a reference scenario for the HZ computations, we evaluated several characteristics of the HZ, such as the distance from the host star at which the habitability is longest, the duration of this habitability, the width of the zone for which the habitability lasts one half of the maximum, and the boundaries of the continuously habitable zone (CHZ) for which the habitability lasts at least 4 Gyr. We developed analytical models, accurate to the percent level or lower, which allowed to obtain these characteristics in dependence on the mass and the chemical composition of the host star. Results: The metallicity of the host star plays a relevant role in determining the HZ. The importance of the initial helium content is evaluated here for the first time; it accounts for a variation of the CHZ boundaries as large as 30% and 10% in the inner and outer border. The computed analytical models allow the first systematic study of the variability of the CHZ boundaries that is caused by the uncertainty in the estimated values of mass and metallicity of the host star. An uncertainty range of about 30% in the inner boundary and 15% in the outer one were found. We also verified that

  11. Development of polyparameter linear free energy relationship models for octanol-air partition coefficients of diverse chemicals.

    PubMed

    Jin, Xiaochen; Fu, Zhiqiang; Li, Xuehua; Chen, Jingwen

    2017-02-03

    The octanol-air partition coefficient (KOA) is a key parameter describing the partition behavior of organic chemicals between air and environmental organic phases. As the experimental determination of KOA is costly, time-consuming and sometimes limited by the availability of authentic chemical standards for the compounds to be determined, it becomes necessary to develop credible predictive models for KOA. In this study, a polyparameter linear free energy relationship (pp-LFER) model for predicting KOA at 298.15 K and a novel model incorporating pp-LFERs with temperature (pp-LFER-T model) were developed from 795 log KOA values for 367 chemicals at different temperatures (263.15-323.15 K), and were evaluated with the OECD guidelines on QSAR model validation and applicability domain description. Statistical results show that both models are well-fitted, robust and have good predictive capabilities. Particularly, the pp-LFER model shows a strong predictive ability for polyfluoroalkyl substances and organosilicon compounds, and the pp-LFER-T model maintains a high predictive accuracy within a wide temperature range (263.15-323.15 K).

  12. Karrikins Identified in Biochars Indicate Post-Fire Chemical Cues Can Influence Community Diversity and Plant Development

    PubMed Central

    Kochanek, Jitka; Flematti, Gavin R.

    2016-01-01

    Background Karrikins are smoke-derived compounds that provide strong chemical cues to stimulate seed germination and seedling growth. The recent discovery in Arabidopsis that the karrikin perception system may be present throughout angiosperms implies a fundamental plant function. Here, we identify the most potent karrikin, karrikinolide (KAR1), in biochars and determine its role in species unique plant responses. Methods Biochars were prepared by three distinct commercial-scale pyrolysis technologies using systematically selected source material and their chemical properties, including karrikinolide, were quantified. Dose-response assays determined the effects of biochar on seed germination for two model species that require karrikinolide to break dormancy (Solanum orbiculatum, Brassica tourneforttii) and on seedling growth using two species that display plasticity to karrikins, biochar and phytotoxins (Lactuca sativa, Lycopersicon esculentum). Multivariate analysis examined relationships between biochar properties and the plant phenotype. Findings and Conclusions Results showed that karrikin abundant biochars stimulated dormant seed germination and seedling growth via mechanisms analogous to post-fire chemical cues. The individual species response was associated with its sensitivity to karrikinolide and inhibitory compounds within the biochars. These findings are critical for understanding why biochar influences community composition and plant physiology uniquely for different species and reaffirms that future pyrolysis technologies promise by-products that concomitantly sequester carbon and enhance plant growth for ecological and broader plant related applications. PMID:27536995

  13. Quantitative structure-activity relationship analysis of acute toxicity of diverse chemicals to Daphnia magna with whole molecule descriptors.

    PubMed

    Moosus, M; Maran, U

    2011-10-01

    Quantitative structure-activity relationship analysis and estimation of toxicological effects at lower-mid trophic levels provide first aid means to understand the toxicity of chemicals. Daphnia magna serves as a good starting point for such toxicity studies and is also recognized for regulatory use in estimating the risk of chemicals. The ECOTOX database was queried and analysed for available data and a homogenous subset of 253 compounds for the endpoint LC50 48 h was established. A four-parameter quantitative structure-activity relationship was derived (coefficient of determination, r (2) = 0.740) for half of the compounds and internally validated (leave-one-out cross-validated coefficient of determination, [Formula: see text] = 0.714; leave-many-out coefficient of determination, [Formula: see text] = 0.738). External validation was carried out with the remaining half of the compounds (coefficient of determination for external validation, [Formula: see text] = 0.634). Two of the descriptors in the model (log P, average bonding information content) capture the structural characteristics describing penetration through bio-membranes. Another two descriptors (energy of highest occupied molecular orbital, weighted partial negative surface area) capture the electronic structural characteristics describing the interaction between the chemical and its hypothetic target in the cell. The applicability domain was subsequently analysed and discussed.

  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

    PubMed Central

    Throckmorton, Kurt; Wiemann, Philipp; Keller, Nancy P.

    2015-01-01

    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. PMID:26378577

  15. Chemical Diversity and Antimicrobial Activity of Volatile Compounds from Zanthoxylum zanthoxyloides Lam. according to Compound Classes, Plant Organs and Senegalese Sample Locations.

    PubMed

    Tine, Yoro; Diop, Abdoulaye; Diatta, William; Desjobert, Jean-Marie; Boye, Cheikh Saad Bouh; Costa, Jean; Wélé, Alassane; Paolini, Julien

    2017-01-01

    The chemical diversity of Zanthoxylum zanthoxyloides growing wild in Senegal was studied according to volatile compound classes, plant organs and sample locations. The composition of fruit essential oil was investigated using an original targeted approach based on the combination of gas chromatography (GC) and liquid chromatography (LC) both coupled with mass spectrometry (MS). The volatile composition of Z. zanthoxyloides fruits exhibited relative high amounts of hydrocarbon monoterpenes (24.3 - 55.8%) and non-terpenic oxygenated compounds (34.5 - 63.1%). The main components were (E)-β-ocimene (12.1 - 39%), octyl acetate (11.6 - 21.8%) and decanol (9.7 - 15.4%). The GC and GC/MS profiling of fruit essential oils showed a chemical variability according to geographical locations of plant material. The LC/MS/MS analysis of fruit oils allowed the detection of seven coumarins in trace content. The chemical composition of fruit essential oils was compared with volatile fractions of leaves and barks (root and trunk) from the same plant station. Hexadecanoic acid, germacrene D and decanal were identified as the major constituents of leaves whereas the barks (root and trunk) were dominated by pellitorine (85.8% and 57%, respectively), an atypic linear compound with amide group. The fruit essential oil exhibited interesting antimicrobial activities against Staphylococcus aureus and Candida albicans, particularly the alcohol fraction of the oil.

  16. Analytical methods for gelatin differentiation from bovine and porcine origins and food products.

    PubMed

    Nhari, Raja Mohd Hafidz Raja; Ismail, Amin; Che Man, Yaakob B

    2012-01-01

    Usage of gelatin in food products has been widely debated for several years, which is about the source of gelatin that has been used, religion, and health. As an impact, various analytical methods have been introduced and developed to differentiate gelatin whether it is made from porcine or bovine sources. The analytical methods comprise a diverse range of equipment and techniques including spectroscopy, chemical precipitation, chromatography, and immunochemical. Each technique can differentiate gelatins for certain extent with advantages and limitations. This review is focused on overview of the analytical methods available for differentiation of bovine and porcine gelatin and gelatin in food products so that new method development can be established.

  17. Mapping tropical biodiversity using spectroscopic imagery : characterization of structural and chemical diversity with 3-D radiative transfer modeling

    NASA Astrophysics Data System (ADS)

    Feret, J. B.; Gastellu-Etchegorry, J. P.; Lefèvre-Fonollosa, M. J.; Proisy, C.; Asner, G. P.

    2014-12-01

    The accelerating loss of biodiversity is a major environmental trend. Tropical ecosystems are particularly threatened due to climate change, invasive species, farming and natural resources exploitation. Recent advances in remote sensing of biodiversity confirmed the potential of high spatial resolution spectroscopic imagery for species identification and biodiversity mapping. Such information bridges the scale-gap between small-scale, highly detailed field studies and large-scale, low-resolution satellite observations. In order to produce fine-scale resolution maps of canopy alpha-diversity and beta-diversity of the Peruvian Amazonian forest, we designed, applied and validated a method based on spectral variation hypothesis to CAO AToMS (Carnegie Airborne Observatory Airborne Taxonomic Mapping System) images, acquired from 2011 to 2013. There is a need to understand on a quantitative basis the physical processes leading to this spectral variability. This spectral variability mainly depends on canopy chemistry, structure, and sensor's characteristics. 3D radiative transfer modeling provides a powerful framework for the study of the relative influence of each of these factors in dense and complex canopies. We simulated series of spectroscopic images with the 3D radiative model DART, with variability gradients in terms of leaf chemistry, individual tree structure, spatial and spectral resolution, and applied methods for biodiversity mapping. This sensitivity study allowed us to determine the relative influence of these factors on the radiometric signal acquired by different types of sensors. Such study is particularly important to define the domain of validity of our approach, to refine requirements for the instrumental specifications, and to help preparing hyperspectral spatial missions to be launched at the horizon 2015-2025 (EnMAP, PRISMA, HISUI, SHALOM, HYSPIRI, HYPXIM). Simulations in preparation include topographic variations in order to estimate the robustness

  18. Analytic materials

    NASA Astrophysics Data System (ADS)

    Milton, Graeme W.

    2016-11-01

    The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional materials, further progress can be made in the identification of analytic materials by using the well-known fact that a 90° rotation applied to a divergence-free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.

  19. Analytic materials.

    PubMed

    Milton, Graeme W

    2016-11-01

    The theory of inhomogeneous analytic materials is developed. These are materials where the coefficients entering the equations involve analytic functions. Three types of analytic materials are identified. The first two types involve an integer p. If p takes its maximum value, then we have a complete analytic material. Otherwise, it is incomplete analytic material of rank p. For two-dimensional materials, further progress can be made in the identification of analytic materials by using the well-known fact that a 90(°) rotation applied to a divergence-free field in a simply connected domain yields a curl-free field, and this can then be expressed as the gradient of a potential. Other exact results for the fields in inhomogeneous media are reviewed. Also reviewed is the subject of metamaterials, as these materials provide a way of realizing desirable coefficients in the equations.

  20. ENVIRONMENTAL ANALYTICAL CHEMISTRY OF ...

    EPA Pesticide Factsheets

    Within the scope of a number of emerging contaminant issues in environmental analysis, one area that has received a great deal of public interest has been the assessment of the role of pharmaceuticals and personal care products (PPCPs) as stressors and agents of change in ecosystems as well as their role in unplanned human exposure. The relationship between personal actions and the occurrence of PPCPs in the environment is clear-cut and comprehensible to the public. In this overview, we attempt to examine the separations aspect of the analytical approach to the vast array of potential analytes among this class of compounds. We also highlight the relationship between these compounds and endocrine disrupting compounds (EDCs) and between PPCPs and EDCs and the more traditional environmental analytes such as the persistent organic pollutants (POPs). Although the spectrum of chemical behavior extends from hydrophobic to hydrophilic, the current focus has shifted to moderately and highly polar analytes. Thus, emphasis on HPLC and LC/MS has grown and MS/MS has become a detection technique of choice with either electrospray ionization or atmospheric pressure chemical ionization. This contrasts markedly with the bench mark approach of capillary GC, GC/MS and electron ionization in traditional environmental analysis. The expansion of the analyte list has fostered new vigor in the development of environmental analytical chemistry, modernized the range of tools appli

  1. High chemical diversity in a wasp pheromone: a blend of methyl 6-methylsalicylate, fatty alcohol acetates and cuticular hydrocarbons releases courtship behavior in the Drosophila parasitoid Asobara tabida.

    PubMed

    Stökl, Johannes; Dandekar, Anna-Teresa; Ruther, Joachim

    2014-02-01

    Wasps of genus Asobara, a larval parasitoid of Drosophila, have become model organisms for the study of host-parasite interactions. However, little is known about the role of pheromones in locating mates and courtship behavior in this genus. In the present study, we aimed to identify the female courtship pheromone in Asobara tabida. The chemical compositions of solvent extracts from male and female wasps were analyzed by GC/MS. These extracts, fractions thereof, and synthetic pheromone candidates were tested for their activity in behavioral bioassays. The results demonstrate that the courtship pheromone of A. tabida is characterized by a remarkable chemical diversity. A multi-component blend of female-specific compounds including methyl 6-methylsalicylate (M6M), fatty alcohol acetates (FAAs), and cuticular hydrocarbons (CHCs) released male courtship behavior. Using a combinatory approach that included both purified natural products and synthetic analogs, it was shown that none of the three chemical classes alone was sufficient to release a full behavioral response in males. However, a blend of M6M and FAAs or combinations of one or both of these with female-derived CHCs resulted in wing-fanning responses by males comparable to those elicited by the crude extract of females. Thus, components from all three chemical classes contribute to the bioactivity of the pheromone, but none of the elements plays a key role or is irreplaceable. The fact that one of the FAAs, vaccenyl acetate, is also used as a kairomone by Asobara females to locate Drosophila hosts suggests that a pre-existing sensory responsiveness to vaccenyl acetate might have been involved in the evolution of the female sex pheromone in Asobara.

  2. Analytical Chemistry Laboratory

    NASA Technical Reports Server (NTRS)

    Anderson, Mark

    2013-01-01

    The Analytical Chemistry and Material Development Group maintains a capability in chemical analysis, materials R&D failure analysis and contamination control. The uniquely qualified staff and facility support the needs of flight projects, science instrument development and various technical tasks, as well as Cal Tech.

  3. A UDP-Glucose:Monoterpenol Glucosyltransferase Adds to the Chemical Diversity of the Grapevine Metabolome1[W

    PubMed Central

    Bönisch, Friedericke; Frotscher, Johanna; Stanitzek, Sarah; Rühl, Ernst; Wüst, Matthias; Bitz, Oliver; Schwab, Wilfried

    2014-01-01

    Terpenoids represent one of the major classes of natural products and serve different biological functions. In grape (Vitis vinifera), a large fraction of these compounds is present as nonvolatile terpene glycosides. We have extracted putative glycosyltransferase (GT) sequences from the grape genome database that show similarity to Arabidopsis (Arabidopsis thaliana) GTs whose encoded proteins glucosylate a diversity of terpenes. Spatial and temporal expression levels of the potential VvGT genes were determined in five different grapevine varieties. Heterologous expression and biochemical assays of candidate genes led to the identification of a UDP-glucose:monoterpenol β-d-glucosyltransferase (VvGT7). The VvGT7 gene was expressed in various tissues in accordance with monoterpenyl glucoside accumulation in grape cultivars. Twelve allelic VvGT7 genes were isolated from five cultivars, and their encoded proteins were biochemically analyzed. They varied in substrate preference and catalytic activity. Three amino acids, which corresponded to none of the determinants previously identified for other plant GTs, were found to be important for enzymatic catalysis. Site-specific mutagenesis along with the analysis of allelic proteins also revealed amino acids that impact catalytic activity and substrate tolerance. These results demonstrate that VvGT7 may contribute to the production of geranyl and neryl glucoside during grape ripening. PMID:24784757

  4. Chemical, physical and microbial properties and microbial diversity in manufactured soils produced from co-composting green waste and biosolids.

    PubMed

    Belyaeva, O N; Haynes, R J; Sturm, E C

    2012-12-01

    The effects of adding biosolids to a green waste feedstock (100% green waste, 25% v/v biosolids or 50% biosolids) on the properties of composted products were investigated. Following initial composting, 20% soil or 20% fly ash/river sand mix was added to the composts as would be carried out commercially to produce manufactured soil. Temperatures during composting reached 50 °C, or above, for 23 days when biosolids were included as a composting feedstock but temperatures barely reached 40 °C when green waste alone was composted. Addition of biosolids to the feedstock increased total N, EC, extractable NH(4), NO(3) and P but lowered pH, macroporosity, water holding capacity, microbial biomass C and basal respiration in composts. Additions of soil or ash/sand to the composts greatly increased the available water holding capacity of the materials. Principal component analysis (PCA) of PCR-DGGE 16S rDNA amplicons separated bacterial communities according to addition of soil to the compost. For fungal ITS-RNA amplicons, PCA separated communities based on the addition of biosolids. Bacterial species richness and Shannon's diversity index were greatest for composts where soil had been added but for fungal communities these parameters were greatest in the treatments where 50% biosolids had been included. These results were interpreted in relation to soil having an inoculation effect and biosolids having an acidifying effect thereby favouring a fungal community.

  5. C15271. The Chemical Diversity of Lantana camara: Analyses of Essential Oil Samples from Cuba, Nepal, and Yemen.

    PubMed

    Satyal, Prabodh; Crouch, Rebecca A; Monzote, Lianet; Cos, Paul; Awadh Ali, Nasser A; Alhaj, Mehdi A; Setzer, William N

    2016-02-10

    The aerial parts of Lantana camara L. were collected from three different geographical locations: Artemisa (Cuba), Biratnagar (Nepal), and Sana'a (Yemen). The essential oils were obtained by hydrodistillation and analyzed by gas chromatography - mass spectrometry. A cluster analysis of 39 L. camara essential oil compositions revealed eight major chemotypes: β-caryophyllene, germacrene D, ar-curcumene/zingiberene, γ-curcumen-15-al/epi-β-bisabolol, (E)-nerolidol, davanone, eugenol/alloaromadendrene, and carvone. The sample from Cuba falls into the group dominated by (E)-nerolidol, the sample from Nepal is a davanone chemotype, and the sample from Yemen belongs to the β-caryophyllene chemotype. The chemical composition of L. camara oil plays a role in the biological activity; the β-caryophyllene and (E)-nerolidol chemotypes showed antimicrobial and cytotoxic activities. This article is protected by copyright. All rights reserved.

  6. Elucidation of Pseurotin Biosynthetic Pathway Points to Trans-Acting C-Methyltransferase and Source of Chemical Diversity Generation**

    PubMed Central

    Tsunematsu, Yuta; Fukutomi, Manami; Saruwatari, Takayoshi; Noguchi, Hiroshi; Watanabe, Kenji; Hotta, Kinya; Tang, Yi

    2015-01-01

    Pseurotins comprise a family of structurally related Aspergillal natural products having interesting bioactivity. However, little is known about the biosynthetic steps involved in the formation of their complex chemical features. Here, we systematically deleted the pseurotin biosynthetic genes in A. fumigatus and performed in vivo and in vitro characterization of the tailoring enzymes to determine the biosynthetic intermediates and the gene products responsible for the formation of each intermediate. This allowed us to elucidate the main biosynthetic steps leading to the formation of pseurotin A from the predominant precursor, azaspirene. The study revealed the combinatorial nature of the biosynthesis of the pseurotin family of compounds and the intermediates. Most interestingly, we report the first identification of an epoxidase–C-methyltransferase bifunctional fusion protein PsoF that appears to methylate the nascent polyketide backbone carbon atom in trans. PMID:24939566

  7. Chemical amplification in an invaded food web: seasonality and ontogeny in a high-biomass, low-diversity ecosystem.

    PubMed

    Ng, Carla A; Berg, Martin B; Jude, David J; Janssen, John; Charlebois, Patrice M; Amaral, Luis A N; Gray, Kimberly A

    2008-10-01

    The global spread of invasive species is changing the structure of aquatic food webs worldwide. The North American Great Lakes have proved particularly vulnerable to this threat. In nearshore areas, invasive benthic species such as dreissenid mussels and round gobies (Neogobius melanostomus) have gained dominance in recent years. Such species are driving the flow of energy and material from the water column to the benthic zone, with dramatic effect on nutrient and contaminant cycling. Here, we develop a stage-structured model of a benthified food web in Lake Michigan with seasonal resolution and show how its bioaccumulation patterns differ from expected ones. Our model suggests that contaminant recycling through the consumption of lipid-rich fish eggs and mussel detritus is responsible for these differences. In southern Lake Michigan's Calumet Harbor (Chicago, IL, USA), round gobies have nitrogen isotope signatures with considerable spread, with some values higher than their predators and others lower than their prey. Contrary to patterns observed in linear pelagic systems, we predict that polychlorinated biphenyl (PCB) concentrations in these fish decrease with increasing size due to the lipid- and benthos-enriched diets of smaller fish. We also present here round goby PCB concentrations measured in 2005 after an invasional succession in Calumet Harbor and demonstrate how the change from one invasive mussel species to another may have led to a decrease in round goby PCB accumulation. Our results suggest that benthic-dominated systems differ from pelagic ones chiefly due to the influence of detritus and that these effects are exacerbated in systems with low species diversity and high biomass.

  8. Post-translational modification and conformational state of Heat Shock Protein 90 differentially affect binding of chemically diverse small molecule inhibitors

    PubMed Central

    Beebe, Kristin; Mollapour, Mehdi; Scroggins, Bradley; Prodromou, Chrisostomos; Xu, Wanping; Tokita, Mari; Taldone, Tony; Pullen, Lester; Zierer, Bettina K.; Lee, Min-Jung; Trepel, Jane; Buchner, Johannes; Bolon, Daniel; Chiosis, Gabriela; Neckers, Leonard

    2013-01-01

    Heat shock protein 90 (Hsp90) is an essential molecular chaperone in eukaryotes that facilitates the conformational maturation and function of a diverse protein clientele, including aberrant and/or over-expressed proteins that are involved in cancer growth and survival. A role for Hsp90 in supporting the protein homeostasis of cancer cells has buoyed interest in the utility of Hsp90 inhibitors as anti-cancer drugs. Despite the fact that all clinically evaluated Hsp90 inhibitors target an identical nucleotide-binding pocket in the N domain of the chaperone, the precise determinants that affect drug binding in the cellular environment remain unclear, and it is possible that chemically distinct inhibitors may not share similar binding preferences. Here we demonstrate that two chemically unrelated Hsp90 inhibitors, the benzoquinone ansamycin geldanamycin and the purine analog PU-H71, select for overlapping but not identical subpopulations of total cellular Hsp90, even though both inhibitors bind to an amino terminal nucleotide pocket and prevent N domain dimerization. Our data also suggest that PU-H71 is able to access a broader range of N domain undimerized Hsp90 conformations than is geldanamycin and is less affected by Hsp90 phosphorylation, consistent with its broader and more potent anti-tumor activity. A more complete understanding of the impact of the cellular milieu on small molecule inhibitor binding to Hsp90 should facilitate their more effective use in the clinic. PMID:23867252

  9. Adapting interrelated two-way clustering method for quantitative structure-activity relationship (QSAR) modeling of mutagenicity/non- mutagenicity of a diverse set of chemicals.

    PubMed

    Majumdar, Subhabrata; Basak, Subhash C; Grunwald, Gregory D

    2013-12-01

    Interrelated Two-way Clustering (ITC) is an unsupervised clustering method developed to divide samples into two groups in gene expression data obtained through microarrays, selecting important genes simultaneously in the process. This has been found to be a better approach than conventional clustering methods like K-means or selforganizing map for the scenarios when number of samples is much smaller than number of variables (n«p). In this paper we used the ITC approach for classification of a diverse set of 508 chemicals regarding mutagenicity. A large number of topological indices (TIs), 3-dimensional, and quantum chemical descriptors, as well as atom pairs (APs) has been used as explanatory variables. In this paper, ITC has been used only for predictor selection, after which ridge regression is employed to build the final predictive model. The proper leave-one-out (LOO) method of cross-validation in this scenario is to take as holdout each of the 508 compounds before predictor thinning and compare the predicted values with the experimental data. ITC based results obtained here are comparable to those developed earlier.

  10. Bitter-sensitive gustatory receptor neuron responds to chemically diverse insect repellents in the common malaria mosquito Anopheles quadrimaculatus

    NASA Astrophysics Data System (ADS)

    Sparks, Jackson T.; Dickens, Joseph C.

    2016-06-01

    Female mosquitoes feed on blood from animal hosts to obtain nutritional resources used for egg production. These contacts facilitate the spread of harmful human diseases. Chemical repellents are used to disrupt mosquito host-seeking and blood-feeding behaviors; however, little is known about the gustatory sensitivity of mosquitoes to known repellents. Here, we recorded electrical responses from gustatory receptor neurons (GRNs) housed within the labellar sensilla of female Anopheles quadrimaculatus to N,N-diethyl-3-methylbenzamide (DEET), picaridin, IR3535, 2-undecanone, p-menthane-3,8-diol, geraniol, trans-2-hexen-1-ol, quinine, and quinidine. A bitter-sensitive GRN responded to all tested repellents and quinine, a known feeding deterrent. Responses of the bitter-sensitive neuron to quinine and an isomer, quinidine, did not differ. Delayed bursts of electrical activity were observed in response to continuous stimulation with synthetic repellents at high concentrations. Electrophysiological recordings from bitter-sensitive GRNs associated with mosquito gustatory sensilla represent a convenient model to evaluate candidate repellents.

  11. The antimicrobial potential of algicolous marine fungi for counteracting multidrug-resistant bacteria: phylogenetic diversity and chemical profiling.

    PubMed

    Gnavi, Giorgio; Palma Esposito, Fortunato; Festa, Carmen; Poli, Anna; Tedesco, Pietro; Fani, Renato; Monti, Maria Chiara; de Pascale, Donatella; D'Auria, Maria Valeria; Varese, Giovanna Cristina

    2016-01-01

    Marine fungi represent an important but still largely unexplored source of novel and potentially bioactive secondary metabolites. The antimicrobial activity of nine sterile mycelia isolated from the green alga Flabellia petiolata collected from the Mediterranean Sea was tested on four antibiotic-resistant bacterial strains using extracellular and intracellular extracts obtained from each fungal strain. The isolated fungi were identified at the molecular level and assigned to one of the Dothideomycetes, Sordariomycetes or Eurotiomycetes classes. Following assessment of inhibition of bacterial growth (IC50), all crude extracts were subjected to preliminary (1)H NMR and TLC analysis. According to preliminary pharmacologic and spectroscopic/chromatographic results, extracts of fungal strains MUT 4865, classified as Beauveria bassiana, and MUT 4861, classified as Microascacea sp.2, were selected for LC-HRMS analysis. Chemical profiling of antibacterial extracts from MUT 4861 and MUT 4865 by LC HRMS allowed identification of the main components of the crude extracts. Several sphingosine bases were identified, including a compound previously unreported from natural sources, which gave a rationale to the broad spectrum of antibacterial activity exhibited.

  12. Clean Water Act Analytical Methods

    EPA Pesticide Factsheets

    EPA publishes laboratory analytical methods (test procedures) that are used by industries and municipalities to analyze the chemical, physical and biological components of wastewater and other environmental samples required by the Clean Water Act.

  13. Analytical testing

    NASA Technical Reports Server (NTRS)

    Flannelly, W. G.; Fabunmi, J. A.; Nagy, E. J.

    1981-01-01

    Analytical methods for combining flight acceleration and strain data with shake test mobility data to predict the effects of structural changes on flight vibrations and strains are presented. This integration of structural dynamic analysis with flight performance is referred to as analytical testing. The objective of this methodology is to analytically estimate the results of flight testing contemplated structural changes with minimum flying and change trials. The category of changes to the aircraft includes mass, stiffness, absorbers, isolators, and active suppressors. Examples of applying the analytical testing methodology using flight test and shake test data measured on an AH-1G helicopter are included. The techniques and procedures for vibration testing and modal analysis are also described.

  14. Frontiers in analytical chemistry

    SciTech Connect

    Amato, I.

    1988-12-15

    Doing more with less was the modus operandi of R. Buckminster Fuller, the late science genius, and inventor of such things as the geodesic dome. In late September, chemists described their own version of this maxim--learning more chemistry from less material and in less time--in a symposium titled Frontiers in Analytical Chemistry at the 196th National Meeting of the American Chemical Society in Los Angeles. Symposium organizer Allen J. Bard of the University of Texas at Austin assembled six speakers, himself among them, to survey pretty widely different areas of analytical chemistry.

  15. Analytical Chemistry Laboratory. Progress report for FY 1996

    SciTech Connect

    Green, D.W.; Boparai, A.S.; Bowers, D.L.

    1996-12-01

    The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1996. This annual report is the thirteenth for the ACL. It describes effort on continuing and new projects and contributions of the ACL staff to various programs at ANL. The ACL operates in the ANL system as a full-cost-recovery service center, but has a mission that includes a complementary research and development component: The Analytical Chemistry Laboratory will provide high-quality, cost-effective chemical analysis and related technical support to solve research problems of our clients -- Argonne National Laboratory, the Department of Energy, and others -- and will conduct world-class research and development in analytical chemistry and its applications. Because of the diversity of research and development work at ANL, the ACL handles a wide range of analytical chemistry problems. Some routine or standard analyses are done, but the ACL usually works with commercial laboratories if our clients require high-volume, production-type analyses. It is common for ANL programs to generate unique problems that require significant development of methods and adaption of techniques to obtain useful analytical data. Thus, much of the support work done by the ACL is very similar to our applied analytical chemistry research.

  16. Analytical Microscopy

    SciTech Connect

    Not Available

    2006-06-01

    In the Analytical Microscopy group, within the National Center for Photovoltaic's Measurements and Characterization Division, we combine two complementary areas of analytical microscopy--electron microscopy and proximal-probe techniques--and use a variety of state-of-the-art imaging and analytical tools. We also design and build custom instrumentation and develop novel techniques that provide unique capabilities for studying materials and devices. In our work, we collaborate with you to solve materials- and device-related R&D problems. This sheet summarizes the uses and features of four major tools: transmission electron microscopy, scanning electron microscopy, the dual-beam focused-ion-beam workstation, and scanning probe microscopy.

  17. Advances in analytical chemistry

    NASA Technical Reports Server (NTRS)

    Arendale, W. F.; Congo, Richard T.; Nielsen, Bruce J.

    1991-01-01

    Implementation of computer programs based on multivariate statistical algorithms makes possible obtaining reliable information from long data vectors that contain large amounts of extraneous information, for example, noise and/or analytes that we do not wish to control. Three examples are described. Each of these applications requires the use of techniques characteristic of modern analytical chemistry. The first example, using a quantitative or analytical model, describes the determination of the acid dissociation constant for 2,2'-pyridyl thiophene using archived data. The second example describes an investigation to determine the active biocidal species of iodine in aqueous solutions. The third example is taken from a research program directed toward advanced fiber-optic chemical sensors. The second and third examples require heuristic or empirical models.

  18. Induction of mutagenesis and transformation in BALB/c-3T3 clone A31-1 cells by diverse chemical carcinogens

    SciTech Connect

    Lubet, R.A. ); Kouri, R.E.; Curren, R.A.; Putman, D.L.; Schechtman, L.M. )

    1990-01-01

    BALB/c-3T3 cells were employed to examine the genotoxic potential of a variety of known chemical carcinogens. BALB/c-3T3 cells displayed a dose-dependent transformation response to a variety of carcinogens (polycyclic hydrocarbons, methylating agents, ethylating agents, aflatoxin B{sub 1} (AFT{sub 1}), and 4-nitroquinoline-N-oxide (4-NQO)). When the ability of these compounds to induce mutagenesis to resistance to the cardiac glycoside ouabain (OUA{sup R}) was examined, the authors found the short chain alkylating agents to be particularly effective mutagens, causing biologic effects at doses below those necessary to induce a transformation response. In contrast, the polycyclic hydrocarbons which were potent transforming agents were weaker, albeit significant, mutagens for the OUA{sup R} locus in this system, while AFB{sub 1} was quite weak. Further studies were performed with 5-azacytidine (5-AZA) and the nongenotoxic carcinogen cinnamyl anthranilate (CIN). 5-AZA was a potent transforming agent, but failed to cause mutagenesis. CIN similarly caused in vitro transformation. When a series of eight structurally diverse compounds were examined in both the BALB/c-3T3 and C3H10T1/2 mouse fibroblast transformation systems, the BALB/c-3T3 system was shown to be sensitive to a wide variety of potential carcinogens, whereas the C3H10T1/2 system proved routinely sensitive only to the polycyclic hydrocarbons.

  19. Chemical diversity of volatiles of Teucrium orientale L. var. orientale, var. puberulens, and var. glabrescens determined by simultaneous GC-FID and GC/MS techniques.

    PubMed

    Ozek, Gulmira; Ozek, Temel; Dinç, Muhittin; Doǧu, Süleyman; Başer, Kemal H C

    2012-06-01

    In the present work, three varieties of Teucrium orientale, var. orientale, var. puberulens, and var. glabrescens, were collected and investigated for chemical composition of the oils. Subsequent gas chromatography (GC-FID) and gas chromatography coupled to mass spectrometry (GC/MS) revealed high abundance of sesquiterpenes in the essential oils analyzed. All the oils contained β-caryophyllene (22.6, 8.5, and 6.3%, resp.) and hexadecanoic acid (7.9, 12.8, and 13.1%). Germacrene D (24.6 and 33.4%) and bicyclogermacrene (6.7 and 8.5%) were found to be the main constituents of var. orientale and var. puberulens, respectively. The high percentages of β-cubebene (26.9%), α-cubebene (9.0%), and α-copaene (7.2%) established the diversity of var. glabrescens. The qualitative difference between the essential oils allowed the differentiation between the varieties in agreement with the morphological observations described in Flora of Turkey for each variety studied. In addition, a cluster analysis of twelve Teucrium taxa based on the essential-oil composition has been carried out. Hovewer, the analysis did not clearly reflect the infrageneric classification of the genus, it largely confirmed the relationships between the infraspecific taxa of Teucrium orientale and T. chamaedrys.

  20. Benchmarking density functional theory predictions of framework structures and properties in a chemically diverse test set of metal-organic frameworks

    SciTech Connect

    Nazarian, Dalar; Ganesh, P.; Sholl, David S.

    2015-01-01

    We compiled a test set of chemically and topologically diverse Metal–Organic Frameworks (MOFs) with high accuracy experimentally derived crystallographic structure data. The test set was used to benchmark the performance of Density Functional Theory (DFT) functionals (M06L, PBE, PW91, PBE-D2, PBE-D3, and vdW-DF2) for predicting lattice parameters, unit cell volume, bonded parameters and pore descriptors. On average PBE-D2, PBE-D3, and vdW-DF2 predict more accurate structures, but all functionals predicted pore diameters within 0.5 Å of the experimental diameter for every MOF in the test set. The test set was also used to assess the variance in performance of DFT functionals for elastic properties and atomic partial charges. The DFT predicted elastic properties such as minimum shear modulus and Young's modulus can differ by an average of 3 and 9 GPa for rigid MOFs such as those in the test set. Moreover, we calculated the partial charges by vdW-DF2 deviate the most from other functionals while there is no significant difference between the partial charges calculated by M06L, PBE, PW91, PBE-D2 and PBE-D3 for the MOFs in the test set. We find that while there are differences in the magnitude of the properties predicted by the various functionals, these discrepancies are small compared to the accuracy necessary for most practical applications.

  1. Interspecies scaling of urinary excretory amounts of nine drugs belonging to different therapeutic areas with diverse chemical structures - accurate prediction of the human urinary excretory amounts.

    PubMed

    Bhamidipati, Ravi Kanth; Mullangi, Ramesh; Srinivas, Nuggehally R

    2017-02-01

    1. The human urinary excretory amounts of total drug (parent + metabolites) were predicted for nine drugs with diverse chemical structures using simple allometry. The drugs used for scaling were cephapirin, olanzapine, labetolol, carisbamate, voriconazole, tofacitinib, nevirapine, ropinirole, and cyclindole. 2. The traditional allometric scaling was attempted using Y = aW(b) relationship. The corresponding predicted urinary amounts were converted into % recovery by using appropriate human dose. Appropriate statistical tests comprising of fold-difference (predicted/observed values) and error calculations (MAE and RMSE) were performed. 3. The interspecies scaling of all nine drugs tested showed excellent correlation (r > 0.9672). The predictions for eight out of nine drugs (exception was cephaphirin) were contained within 0.80-1.25 fold-differences. The MAE and RMSE were within ± 18% and 14.64%, respectively. 4. The present work supported the potential application of prospective allometry scaling to predict the urinary excretory amounts of the total drug and gauge any issues for the renal handling of the total drug.

  2. Analytical Chemistry and the Microchip.

    ERIC Educational Resources Information Center

    Lowry, Robert K.

    1986-01-01

    Analytical techniques used at various points in making microchips are described. They include: Fourier transform infrared spectrometry (silicon purity); optical emission spectroscopy (quantitative thin-film composition); X-ray photoelectron spectroscopy (chemical changes in thin films); wet chemistry, instrumental analysis (process chemicals);…

  3. Analytical approaches to metabolomics and applications to systems biology.

    PubMed

    Wang, Jeffrey H; Byun, Jaeman; Pennathur, Subramaniam

    2010-09-01

    Phenotypic expression of renal diseases encompasses a complex interaction between genetic, environmental, and local tissue factors. The level of complexity requires integrated understanding of perturbations in the network of genes, proteins, and metabolites. Metabolomics attempts to systematically identify and quantitate metabolites from biological samples. The small molecules represent the end result of complexity of biological processes in a given cell, tissue, or organ, and thus form attractive candidates to understand disease phenotypes. Metabolites represent a diverse group of low-molecular-weight structures including lipids, amino acids, peptides, nucleic acids, and organic acids, which makes comprehensive analysis a difficult analytical challenge. The recent rapid development of a variety of analytical platforms based on mass spectrometry and nuclear magnetic resonance have enabled separation, characterization, detection, and quantification of such chemically diverse structures. Continued development of bioinformatics and analytical strategies will accelerate widespread use and integration of metabolomics into systems biology. Here, we will discuss analytical and bioinformatic techniques and highlight recent studies that use metabolomics in understanding pathophysiology of disease processes.

  4. Polymers for Chemical Sensors Using Hydrosilylation Chemistry

    SciTech Connect

    Grate, Jay W.; Kaganove, Steven N.; Nelson, David A.

    2001-06-28

    Sorbent and functionalized polymers play a key role in a diverse set of fields, including chemical sensors, separation membranes, solid phase extraction techniques, and chromatography. Sorbent polymers are critical to a number of sensor array or "electronic nose" systems. The responses of the sensors in the array give rise to patterns that can be used to distinguish one compound from another, provided that a sufficiently diverse set of sensing materials is present in the array. Figure 1 illustrates the concept of several sensors, each with a different sensor coating, giving rise to variable responses to an analyte that appear as a pattern in bar graph format. Using hydrosilylation as the bond-forming reaction, we have developed a versatile and efficient approach to developing sorbent polymers with diverse interactive properties for sensor applications. Both the chemical and physical properties of these polymers are predictable and tunable by design.

  5. Chemicals of emerging concern in water and bottom sediment in the Great Lakes Basin, 2012: collection methods, analytical methods, quality assurance, and study data

    USGS Publications Warehouse

    Lee, Kathy E.; Langer, Susan K.; Menheer, Michael A.; Hansen, Donald S.; Foreman, William T.; Furlong, Edward T.; Jorgenson, Zachary G.; Choy, Steven J.; Moore, Jeremy N.; Banda, JoAnn; Gefell, Daniel J.

    2015-01-01

    During this study, 53 environmental samples, 4 field duplicate samples, and 8 field spike samples of bottom sediment and laboratory matrix-spike samples were analyzed for a wide variety of CECs at the USGS National Water Quality Laboratory using laboratory schedule 5433 for wastewater indicators; research method 6434 for steroid hormones, sterols, and bisphenol A; and research method 9008 for human-use pharmaceuticals and antidepressants. Forty of the 57 chemicals analyzed using laboratory schedule 5433 had detectable concentrations ranging from 1 to 49,000 micrograms per kilogram. Fourteen of the 20 chemicals analyzed using research method 6434 had detectable concentrations ranging from 0.04 to 24,940 nanograms per gram. Ten of the 20 chemicals analyzed using research method 9008 had detectable concentrations ranging from 0.59 to 197.5 micrograms per kilogram. Five of the 11 chemicals analyzed using research method 9008 had detectable concentrations ranging from 1.16 to 25.0 micrograms per kilogram.

  6. Diverse Thinking about Diversity

    ERIC Educational Resources Information Center

    Kaplan, Sandra N.

    2013-01-01

    This article focuses on the concept of diversity in educational decision making. It is noted that the differences that distinguish the needs, interests and abilities are identified by educators. It lists misconceptions resulting from not attending to within-group diversity, and states that a "loss of self" for individual members of…

  7. Chemically sensitive interfaces on SAW devices

    SciTech Connect

    Ricco, A.J.; Martin, S.J.; Crooks, R.M.; Xu, Chuanjing; Allred, R.E.

    1993-11-01

    Using surface acoustic wave (SAW) devices, three approaches to the effective use of chemically sensitive interfaces that are not highly chemically selective have been examined: (1) molecular identification from time-resolved permeation transients; (2) using multifrequency SAW devices to determine the frequency dependence of analyte/film interactions; (3) use of an array of SAW devices bearing diverse chemically sensitive interfaces to produce a distinct response pattern for each analyte. In addition to their well-known sensitivity to mass changes (0.0035 monolayer of N{sub 2} can be measured), SAW devices respond to the mechanical and electronic properties of thin films, enhancing response information content but making a thorough understanding of the perturbation critical. Simultaneous measurement of changes in frequency and attenuation, which can provide the information necessary to determine the type of perturbation, are used as part of the above discrimination schemes.

  8. Molecular tools for chemical biotechnology

    PubMed Central

    Galanie, Stephanie; Siddiqui, Michael S.; Smolke, Christina D.

    2013-01-01

    Biotechnological production of high value chemical products increasingly involves engineering in vivo multi-enzyme pathways and host metabolism. Recent approaches to these engineering objectives have made use of molecular tools to advance de novo pathway identification, tunable enzyme expression, and rapid pathway construction. Molecular tools also enable optimization of single enzymes and entire genomes through diversity generation and screening, whole cell analytics, and synthetic metabolic control networks. In this review, we focus on advanced molecular tools and their applications to engineered pathways in host organisms, highlighting the degree to which each tool is generalizable. PMID:23528237

  9. Benchmarking density functional theory predictions of framework structures and properties in a chemically diverse test set of metal-organic frameworks

    DOE PAGES

    Nazarian, Dalar; Ganesh, P.; Sholl, David S.

    2015-01-01

    We compiled a test set of chemically and topologically diverse Metal–Organic Frameworks (MOFs) with high accuracy experimentally derived crystallographic structure data. The test set was used to benchmark the performance of Density Functional Theory (DFT) functionals (M06L, PBE, PW91, PBE-D2, PBE-D3, and vdW-DF2) for predicting lattice parameters, unit cell volume, bonded parameters and pore descriptors. On average PBE-D2, PBE-D3, and vdW-DF2 predict more accurate structures, but all functionals predicted pore diameters within 0.5 Å of the experimental diameter for every MOF in the test set. The test set was also used to assess the variance in performance of DFT functionalsmore » for elastic properties and atomic partial charges. The DFT predicted elastic properties such as minimum shear modulus and Young's modulus can differ by an average of 3 and 9 GPa for rigid MOFs such as those in the test set. Moreover, we calculated the partial charges by vdW-DF2 deviate the most from other functionals while there is no significant difference between the partial charges calculated by M06L, PBE, PW91, PBE-D2 and PBE-D3 for the MOFs in the test set. We find that while there are differences in the magnitude of the properties predicted by the various functionals, these discrepancies are small compared to the accuracy necessary for most practical applications.« less

  10. Elevated CO(2) and drought stress effects on the chemical composition of maize plants, their ruminal fermentation and microbial diversity in vitro.

    PubMed

    Meibaum, Birgit; Riede, Susanne; Schröder, Bernd; Manderscheid, Remy; Weigel, Hans-Joachim; Breves, Gerhard

    2012-12-01

    Climate changes are supposed to influence productivity and chemical composition of plants. In the present experiments, it was hypothesised that the incubation of plants exposed to elevated atmospheric carbon dioxide concentrations ([CO₂]) and drought stress will result in different ruminal fermentation pattern and microbial diversity compared to unaffected plants. Maize plants were grown, well-watered under ambient (380 ppm CO₂, Variant A) and elevated [CO₂] (550 ppm CO₂, Variant B). Furthermore, each CO₂ treatment was also exposed to drought stress (380 ppm and 550 ppm CO₂,Variants C and D, respectively), which received only half as much water as the well-watered plants. Plant material from these treatments was incubated in a semi-continuous in vitro fermentation experiment using the rumen simulation technique. Single strand conformation polymorphism (SSCP) analysis was conducted for Bacteria and Archaea specific profiles. The analysis of crude nutrients showed higher contents of fibre fraction in drought stress Variants C and D. Crude protein content was increased by drought stress under ambient but not under elevated [CO₂]. Fermentation of drought stress variants resulted in significantly increased pH values, decreased digestibilities of organic matter and increased ammonia-N (NH₃-N) concentrations compared with well-watered variants. Additionally, the 550 ppm CO₂ Variants B and D showed significantly lower NH₃-N concentrations than Variants A and C. The Bacteria- and Archaea-specific SSCP profiles as well as the production rates of short-chain fatty acids and their molar percentages were not affected by treatments. During the first four days of equilibration period, a decrease of molar percentage of acetate and increased molar percentages of propionate were observed for all treatments. These alterations might have been induced by adaptation of the in vitro system to the new substrate. The rumen microflora appeared to be highly adaptive and

  11. Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition – A facile method for encapsulation of diverse cell types in silica matrices

    DOE PAGES

    Johnston, Robert; Rogelj, Snezna; Harper, Jason C.; ...

    2014-12-12

    In nature, cells perform a variety of complex functions such as sensing, catalysis, and energy conversion which hold great potential for biotechnological device construction. However, cellular sensitivity to ex vivo environments necessitates development of bio–nano interfaces which allow integration of cells into devices and maintain their desired functionality. In order to develop such an interface, the use of a novel Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition process for whole cell encapsulation in silica was explored. In SG-CViL, the high vapor pressure of tetramethyl orthosilicate (TMOS) is utilized to deliver silica into an aqueous medium, creating a silica sol. Cellsmore » are then mixed with the resulting silica sol, facilitating encapsulation of cells in silica while minimizing cell contact with the cytotoxic products of silica generating reactions (i.e. methanol), and reduce exposure of cells to compressive stresses induced from silica condensation reactions. Using SG-CVIL, Saccharomyces cerevisiae (S. cerevisiae) engineered with an inducible beta galactosidase system were encapsulated in silica solids and remained both viable and responsive 29 days post encapsulation. By tuning SG-CViL parameters, thin layer silica deposition on mammalian HeLa and U87 human cancer cells was also achieved. Furthermore, the ability to encapsulate various cell types in either a multi cell (S. cerevisiae) or a thin layer (HeLa and U87 cells) fashion shows the promise of SG-CViL as an encapsulation strategy for generating cell–silica constructs with diverse functions for incorporation into devices for sensing, bioelectronics, biocatalysis, and biofuel applications.« less

  12. Sol-Generating Chemical Vapor into Liquid (SG-CViL) Deposition- A Facile Method for Encapsulation of Diverse Cell Types in Silica Matrices

    PubMed Central

    Johnston, Robert; Rogelj, Snezna; Harper, Jason C.; Tartis, Michaelann

    2014-01-01

    In nature, cells perform a variety of complex functions such as sensing, catalysis, and energy conversion which hold great potential for biotechnological device construction. However, cellular sensitivity to ex-vivo environments necessitates development of bio-nano interfaces which allow integration of cells into devices and maintain their desired functionality. In order to develop such an interface, the use of a novel Sol Generating Chemical Vapor into Liquid (SG-CViL) deposition process for whole cell encapsulation in silica was explored. In SG-CViL, the high vapor pressure of tetramethyl orthosilicate (TMOS) is utilized to deliver silica into an aqueous medium, creating a silica sol. Cells are then mixed with the resulting silica sol, facilitating encapsulation of cells in silica while minimizing cell contact with the cytotoxic products of silica generating reactions (i.e. methanol), and reduce exposure of cells to compressive stresses induced from silica condensation reactions. Using SG-CVIL, Saccharomyces cerevisiae (S. cerevisiae) engineered with an inducible beta galactosidase system were encapsulated in silica solids and remained both viable and responsive 29 days post encapsulation. By tuning SG-CViL parameters thin layer silica deposition on mammalian HeLa and U87 human cancer cells was also achieved. The ability to encapsulate various cell types in either a multi cell (S. cerevisiae) or a thin layer (HeLa and U87 cells) fashion shows the promise of SG-CViL as an encapsulation strategy for generating cell-silica constructs with diverse functions for incorporation into devices for sensing, bioelectronics, biocatalysis, and biofuel applications. PMID:25688296

  13. Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition – A facile method for encapsulation of diverse cell types in silica matrices

    SciTech Connect

    Johnston, Robert; Rogelj, Snezna; Harper, Jason C.; Tartis, Michaelann

    2014-12-12

    In nature, cells perform a variety of complex functions such as sensing, catalysis, and energy conversion which hold great potential for biotechnological device construction. However, cellular sensitivity to ex vivo environments necessitates development of bio–nano interfaces which allow integration of cells into devices and maintain their desired functionality. In order to develop such an interface, the use of a novel Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition process for whole cell encapsulation in silica was explored. In SG-CViL, the high vapor pressure of tetramethyl orthosilicate (TMOS) is utilized to deliver silica into an aqueous medium, creating a silica sol. Cells are then mixed with the resulting silica sol, facilitating encapsulation of cells in silica while minimizing cell contact with the cytotoxic products of silica generating reactions (i.e. methanol), and reduce exposure of cells to compressive stresses induced from silica condensation reactions. Using SG-CVIL, Saccharomyces cerevisiae (S. cerevisiae) engineered with an inducible beta galactosidase system were encapsulated in silica solids and remained both viable and responsive 29 days post encapsulation. By tuning SG-CViL parameters, thin layer silica deposition on mammalian HeLa and U87 human cancer cells was also achieved. Furthermore, the ability to encapsulate various cell types in either a multi cell (S. cerevisiae) or a thin layer (HeLa and U87 cells) fashion shows the promise of SG-CViL as an encapsulation strategy for generating cell–silica constructs with diverse functions for incorporation into devices for sensing, bioelectronics, biocatalysis, and biofuel applications.

  14. Sol-Generating Chemical Vapor into Liquid (SG-CViL) Deposition- A Facile Method for Encapsulation of Diverse Cell Types in Silica Matrices.

    PubMed

    Johnston, Robert; Rogelj, Snezna; Harper, Jason C; Tartis, Michaelann

    2015-02-14

    In nature, cells perform a variety of complex functions such as sensing, catalysis, and energy conversion which hold great potential for biotechnological device construction. However, cellular sensitivity to ex-vivo environments necessitates development of bio-nano interfaces which allow integration of cells into devices and maintain their desired functionality. In order to develop such an interface, the use of a novel Sol Generating Chemical Vapor into Liquid (SG-CViL) deposition process for whole cell encapsulation in silica was explored. In SG-CViL, the high vapor pressure of tetramethyl orthosilicate (TMOS) is utilized to deliver silica into an aqueous medium, creating a silica sol. Cells are then mixed with the resulting silica sol, facilitating encapsulation of cells in silica while minimizing cell contact with the cytotoxic products of silica generating reactions (i.e. methanol), and reduce exposure of cells to compressive stresses induced from silica condensation reactions. Using SG-CVIL, Saccharomyces cerevisiae (S. cerevisiae) engineered with an inducible beta galactosidase system were encapsulated in silica solids and remained both viable and responsive 29 days post encapsulation. By tuning SG-CViL parameters thin layer silica deposition on mammalian HeLa and U87 human cancer cells was also achieved. The ability to encapsulate various cell types in either a multi cell (S. cerevisiae) or a thin layer (HeLa and U87 cells) fashion shows the promise of SG-CViL as an encapsulation strategy for generating cell-silica constructs with diverse functions for incorporation into devices for sensing, bioelectronics, biocatalysis, and biofuel applications.

  15. Nonlocal effects in double fishnet metasurfaces nanostructured at deep subwavelength level as a path toward simultaneous sensing of multiple chemical analytes

    NASA Astrophysics Data System (ADS)

    Tanasković, Dragan; Obradov, Marko; Jakšić, Olga; Jakšić, Zoran

    2016-01-01

    Nanoplasmonic devices are among the most sensitive chemical sensors, with sensitivities reaching the single-molecule level. An especially convenient class of such sensors is that based on metasurfaces with subwavelength nanoholes, examples being extraordinary optical transmission arrays and double fishnet structures. Such structures ensure operation both in transmission and reflection mode and ensure high sensitivities and excellent coupling with external readout. In this paper we consider the possibility to tailor the response of aperture-based sensor structures by modifying the geometry of nanoholes at the deep subwavelength level through ensuring controlled use of nonlocal effects. We investigate the case where nonlocality is achieved by modifying the basic metamaterial fishnet structure (a metal-dielectric-metal sandwich with rectangular openings) by superposing additional subwavelength patterns, ensuring the appearance of new optical modes. The obtained unit cell superstructure will have multiple tailorable spectral peaks that will increase the selectivity at different wavelengths. The finite elements method was used for simulations of the proposed structures. As an example, we applied our results to the case of a benzene sensor, showing that its spectral properties and selectivity can be tuned by modifying geometry at a deep subwavelength scale. The obtained custom-designed spectral selectivity is convenient for multianalyte chemical sensing using a single structure.

  16. Chemical speciation of arsenic-accumulating mineral in a sedimentary iron deposit by synchrotron radiation multiple X-ray analytical techniques.

    PubMed

    Endo, Satoshi; Terada, Yasuko; Kato, Yasuhiro; Nakai, Izumi

    2008-10-01

    The comprehensive characterization of As(V)-bearing iron minerals from the Gunma iron deposit, which were probably formed by biomineralization, was carried out by utilizing multiple synchrotron radiation (SR)-based analytical techniques at BL37XU at SPring-8. SR microbeam X-ray fluorescence (SR-mu-XRF) imaging showed a high level of arsenic accumulation in the iron ore as dots of ca. 20 microm. Based on SEM observations and SR X-ray powder diffraction (SR-XRD) analysis, it was found that arsenic is selectively accumulated in strengite (FePO4 x 2H2O) with a concentric morphology, which may be produced by a biologically induced process. Furthermore, the X-ray absorption fine structure (XAFS) analysis showed that arsenic in strengite exists in the arsenate (AsO4(3-)) form and is coordinated by four oxygen atoms at 1.68 angstroms. The results suggest that strengite accumulates arsenic by isomorphous substitution of AsO4(3-) for PO4(3-) to form a partial solid-solution of strengite and scorodite (FeAsO4 x 2H2O). The specific correlation between the distribution of As and biominerals indicates that microorganisms seems to play an important role in the mineralization of strengite in combination with an arsenic-accumulating process.

  17. Prioritizing pesticide compounds for analytical methods development

    USGS Publications Warehouse

    Norman, Julia E.; Kuivila, Kathryn; Nowell, Lisa H.

    2012-01-01

    compounds are high priority as new analytes. The objective for analytical methods development is to design an integrated analytical strategy that includes as many of the Tier 1 pesticide compounds as possible in a relatively few, cost-effective methods. More than 60 percent of the Tier 1 compounds are high priority because they are anticipated to be present at concentrations approaching levels that could be of concern to human health or aquatic life in surface water or groundwater. An additional 17 percent of Tier 1 compounds were frequently detected in monitoring studies, but either were not measured at levels potentially relevant to humans or aquatic organisms, or do not have benchmarks available with which to compare concentrations. The remaining 21 percent are pesticide degradates that were included because their parent pesticides were in Tier 1. Tier 1 pesticide compounds for water span all major pesticide use groups and a diverse range of chemical classes, with herbicides and their degradates composing half of compounds. Many of the high priority pesticide compounds also are in several national regulatory programs for water, including those that are regulated in drinking water by the U.S. Environmental Protection Agency under the Safe Drinking Water Act and those that are on the latest Contaminant Candidate List. For sediment, a total of 175 pesticide compounds were classified as Tier 1 and, thus, are high priority for inclusion in analytical methods available for monitoring and studies. More than 60 percent of these compounds are included in some USGS analytical method; however, some are spread across several research methods that are expensive to perform, and monitoring data are not extensive for many compounds. The remaining Tier 1 compounds for sediment are high priority as new analytes. The objective for analytical methods development for sediment is to enhance an existing analytical method that currently includes nearly half of the pesticide compounds in Tier 1

  18. Replacement of chemical oxygen demand (COD) with total organic carbon (TOC) for monitoring wastewater treatment performance to minimize disposal of toxic analytical waste.

    PubMed

    Dubber, Donata; Gray, Nicholas F

    2010-10-01

    Chemical oxygen demand (COD) is widely used for wastewater monitoring, design, modeling and plant operational analysis. However this method results in the production of hazardous wastes including mercury and hexavalent chromium. The study examined the replacement of COD with total organic carbon (TOC) for general performance monitoring by comparing their relationship with influent and effluent samples from 11 wastewater treatment plants. Biochemical oxygen demand (BOD5) was also included in the comparison as a control. The results show significant linear relationships between TOC, COD and BOD5 in settled (influent) domestic and municipal wastewaters, but only between COD and TOC in treated effluents. The study concludes that TOC can be reliably used for the generic replacement of both COD (COD=49.2+3.00*TOC) and BOD5 (BOD5=23.7+1.68*TOC) in influent wastewaters but only for COD (COD=7.25+2.99*TOC) in final effluents.

  19. Analytical Services Management System

    SciTech Connect

    Church, Shane; Nigbor, Mike; Hillman, Daniel

    2005-03-30

    Analytical Services Management System (ASMS) provides sample management services. Sample management includes sample planning for analytical requests, sample tracking for shipping and receiving by the laboratory, receipt of the analytical data deliverable, processing the deliverable and payment of the laboratory conducting the analyses. ASMS is a web based application that provides the ability to manage these activities at multiple locations for different customers. ASMS provides for the assignment of single to multiple samples for standard chemical and radiochemical analyses. ASMS is a flexible system which allows the users to request analyses by line item code. Line item codes are selected based on the Basic Ordering Agreement (BOA) format for contracting with participating laboratories. ASMS also allows contracting with non-BOA laboratories using a similar line item code contracting format for their services. ASMS allows sample and analysis tracking from sample planning and collection in the field through sample shipment, laboratory sample receipt, laboratory analysis and submittal of the requested analyses, electronic data transfer, and payment of the laboratories for the completed analyses. The software when in operation contains business sensitive material that is used as a principal portion of the Kaiser Analytical Management Services business model. The software version provided is the most recent version, however the copy of the application does not contain business sensitive data from the associated Oracle tables such as contract information or price per line item code.

  20. Capacitive chemical sensor

    DOEpatents

    Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R

    2014-05-27

    A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

  1. Guidelines for sample collecting and analytical methods used in the U.S. Geological Survey for determining chemical composition of coal

    USGS Publications Warehouse

    Swanson, Vernon Emanuel; Huffman, Claude

    1976-01-01

    This report is intended to meet the many requests for information on current U.S. Geological Survey procedures in handling coal samples. In general, the exact type and number of samples of coal and associated rock to be collected are left to the best judgment of the geologist. Samples should be of unweathered coal or rock and representative of the bed or beds sampled; it is recommended that two channel samples, separated by 10 to 100 yards (10 to 100 metres) and weighing 4 to 5 pounds ( 1.8 to 2.3 kilograms) each, be collected of each 5 feet ( 1.5 metres) of vertical section. Care must be taken to avoid any sample contamination, and to record the exact locality, thickness, and stratigraphic information for each sample. Analytical methods are described for the determination of major, minor, and trace elements in coal. Hg, As, Sb, F, Se, U, and Th are determined in the raw coal, and the following 34 elements are determined after ashing the coal: Si, Al, Ca, Mg, Na, K, Fe (total), Cl, Ti, Mn, P, S (total), Cd, Li, Cu, Zn, Pb, B, Ba, Be, Co, Cr, Ga, La, Mo, Nb, Ni, Sc, Sr, Ti, V, Y, Yb, and Zr. The methods used to determine these elements include atomic absorption spectroscopy, X-ray fluorescence spectroscopy, optical emission spectroscopy, spectrophotometry, selective-ion electrode, and neutron activation analysis. A split of representative coal samples is submitted to the U.S. Bureau of Mines for proximate, ultimate, forms of sulfur, and Btu determinations.

  2. Photoacoustic spectroscopy for chemical detection

    NASA Astrophysics Data System (ADS)

    Holthoff, Ellen L.; Pellegrino, Paul M.

    2012-06-01

    The Global War on Terror has made rapid detection and identification of chemical and biological agents a priority for Military and Homeland Defense applications. Reliable real-time detection of these threats is complicated by our enemy's use of a diverse range of materials. Therefore, an adaptable platform is necessary. Photoacoustic spectroscopy (PAS) is a useful monitoring technique that is well suited for trace detection of gaseous media. This method routinely exhibits detection limits at the parts-per-billion (ppb) or sub-ppb range. The versatility of PAS also allows for the investigation of solid and liquid analytes. Current research utilizes quantum cascade lasers (QCLs) in combination with an air-coupled solid-phase photoacoustic cell design for the detection of condensed phase material films deposited on a surface. Furthermore, variation of the QCL pulse repetition rate allows for identification and molecular discrimination of analytes based solely on photoacoustic spectra collected at different film depths.

  3. Analysis of the Effects of Cell Stress and Cytotoxicity on In Vitro Assay Activity Across a Diverse Chemical and Assay Space

    EPA Science Inventory

    Chemical toxicity can arise from disruption of specific biomolecular functions or through more generalized cell stress and cytotoxicity-mediated processes. Here, concentration-dependent responses of 1063 chemicals including pharmaceuticals, natural products, pesticidals, consumer...

  4. Fate of Escherichia coli O157:H7 and bacterial diversity in corn silage contaminated with the pathogen and treated with chemical or microbial additives.

    PubMed

    Ogunade, I M; Jiang, Y; Kim, D H; Cervantes, A A Pech; Arriola, K G; Vyas, D; Weinberg, Z G; Jeong, K C; Adesogan, A T

    2017-03-01

    Inhibiting the growth of Escherichia coli O157:H7 (EC) in feeds may prevent the transmission or cycling of the pathogen on farms. The first objective of this study was to examine if addition of propionic acid or microbial inoculants would inhibit the growth of EC during ensiling, at silo opening, or after aerobic exposure. The second objective was to examine how additives affected the bacterial community composition in corn silage. Corn forage was harvested at approximately 35% dry matter, chopped to a theoretical length of cut of 10 mm, and ensiled after treatment with one of the following: (1) distilled water (control); (2) 1 × 10(5) cfu/g of EC (ECCH); (3) EC and 1 × 10(6) cfu/g of Lactobacillus plantarum (ECLP); (4) EC and 1 × 10(6) cfu/g of Lactobacillus buchneri (ECLB); and (5) EC and 2.2 g/kg (fresh weight basis) of propionic acid, containing 99.5% of the acid (ECA). Each treatment was ensiled in quadruplicate in laboratory silos for 0, 3, 7, and 120 d and analyzed for EC, pH, and organic acids. Samples from d 0 and 120 were also analyzed for chemical composition. Furthermore, samples from d 120 were analyzed for ammonia N, yeasts and molds, lactic acid bacteria, bacterial community composition, and aerobic stability. The pH of silages from all treatments decreased below 4 within 3 d of ensiling. Escherichia coli O157:H7 counts were below the detection limit in all silages after 7 d of ensiling. Treatment with L. buchneri and propionic acid resulted in fewer yeasts and greater aerobic stability compared with control, ECCH, and ECLP silages. Compared with the control, the diversity analysis revealed a less diverse bacterial community in the ECLP silage and greater abundance of Lactobacillus in the ECLP and ECA silages. The ECLB silage also contained greater abundance of Acinetobacter and Weissella than other silages. Subsamples of silages were reinoculated with 5 × 10(5) cfu/g of EC either immediately after silo opening or after 168 h of aerobic exposure

  5. 1998 Chemical Technology Division Annual Technical Report.

    SciTech Connect

    Ackerman, J.P.; Einziger, R.E.; Gay, E.C.; Green, D.W.; Miller, J.F.

    1999-08-06

    The Chemical Technology (CMT) Division is a diverse technical organization with principal emphases in environmental management and development of advanced energy sources. The Division conducts research and development in three general areas: (1) development of advanced power sources for stationary and transportation applications and for consumer electronics, (2) management of high-level and low-level nuclear wastes and hazardous wastes, and (3) electrometallurgical treatment of spent nuclear fuel. The Division also performs basic research in catalytic chemistry involving molecular energy resources, mechanisms of ion transport in lithium battery electrolytes, and the chemistry of technology-relevant materials. In addition, the Division operates the Analytical Chemistry Laboratory, which conducts research in analytical chemistry and provides analytical services for programs at Argonne National Laboratory (ANL) and other organizations. Technical highlights of the Division's activities during 1998 are presented.

  6. Chemical Technology Division annual technical report 1997

    SciTech Connect

    1998-06-01

    The Chemical Technology (CMT) Division is a diverse technical organization with principal emphases in environmental management and development of advanced energy sources. The Division conducts research and development in three general areas: (1) development of advanced power sources for stationary and transportation applications and for consumer electronics, (2) management of high-level and low-level nuclear wastes and hazardous wastes, and (3) electrometallurgical treatment of spent nuclear fuel. The Division also performs basic research in catalytic chemistry involving molecular energy resources, mechanisms of ion transport in lithium battery electrolytes, and the chemistry of technology-relevant materials and electrified interfaces. In addition, the Division operates the Analytical Chemistry Laboratory, which conducts research in analytical chemistry and provides analytical services for programs at Argonne National Laboratory (ANL) and other organizations. Technical highlights of the Division`s activities during 1997 are presented.

  7. Feedbacks Between Numerical and Analytical Models in Hydrogeology

    NASA Astrophysics Data System (ADS)

    Zlotnik, V. A.; Cardenas, M. B.; Toundykov, D.; Cohn, S.

    2012-12-01

    Hydrogeology is a relatively young discipline which combines elements of Earth science and engineering. Mature fundamental disciplines (e.g., physics, chemistry, fluid mechanics) have centuries-long history of mathematical modeling even prior to discovery of Darcy's law. Thus, in hydrogeology, relatively few classic analytical models (such those by Theis, Polubarinova-Kochina, Philip, Toth, Henry, Dagan, Neuman) were developed by the early 1970's. The advent of computers and practical demands refocused mathematical models towards numerical techniques. With more diverse but less mathematically-oriented training, most hydrogeologists shifted from analytical methods to use of standardized computational software. Spatial variability in internal properties and external boundary conditions and geometry, and the added complexity of chemical and biological processes will remain major challenges for analytical modeling. Possibly, analytical techniques will play a subordinate role to numerical approaches in many applications. On the other hand, the rise of analytical element modeling of groundwater flow is a strong alternative to numerical models when data demand and computational efficiency is considered. The hallmark of analytical models - transparency and accuracy - will remain indispensable for scientific exploration of complex phenomena and for benchmarking numerical models. Therefore, there will always be feedbacks and complementarities between numerical and analytical techniques, as well as a certain ideological schism among various views to modeling. We illustrate the idea of feedbacks by reviewing evolution of Joszef Toth's analytical model of gravity driven flow systems. Toth's (1963) approach was to reduce the flow domain to a rectangle which allowed for closed-form solution of the governing equations. Succeeding numerical finite-element models by Freeze and Witherspoon (1966-1968) explored the effects of geometry and heterogeneity on regional groundwater flow

  8. Climate, energy and diversity

    PubMed Central

    Clarke, Andrew; Gaston, Kevin J

    2006-01-01

    In recent years, a number of species–energy hypotheses have been developed to explain global patterns in plant and animal diversity. These hypotheses frequently fail to distinguish between fundamentally different forms of energy which influence diversity in dissimilar ways. Photosynthetically active radiation (PAR) can be utilized only by plants, though their abundance and growth rate is also greatly influenced by water. The Gibbs free energy (chemical energy) retained in the reduced organic compounds of tissue can be utilized by all heterotrophic organisms. Neither PAR nor chemical energy influences diversity directly. Both, however, influence biomass and/or abundance; diversity may then increase as a result of secondary population dynamic or evolutionary processes. Temperature is not a form of energy, though it is often used loosely by ecologists as a proxy for energy; it does, however, influence the rate of utilization of chemical energy by organisms. It may also influence diversity by allowing a greater range of energetic lifestyles at warmer temperatures (the metabolic niche hypothesis). We conclude that there is no single species/energy mechanism; fundamentally different processes link energy to abundance in plants and animals, and diversity is affected secondarily. If we are to make progress in elucidating these mechanisms, it is important to distinguish climatic effects on species' distribution and abundance from processes linking energy supply to plant and animal diversity. PMID:16928626

  9. Guide to Savannah River Laboratory Analytical Services Group

    SciTech Connect

    Not Available

    1990-04-01

    The mission of the Analytical Services Group (ASG) is to provide analytical support for Savannah River Laboratory Research and Development Programs using onsite and offsite analytical labs as resources. A second mission is to provide Savannah River Site (SRS) operations with analytical support for nonroutine material characterization or special chemical analyses. The ASG provides backup support for the SRS process control labs as necessary.

  10. Automation and quality in analytical laboratories

    SciTech Connect

    Valcarcel, M.; Rios, A.

    1994-05-01

    After a brief introduction to the generic aspects of automation in analytical laboratories, the different approaches to quality in analytical chemistry are presented and discussed to establish the following different facets emerging from the combination of quality and automation: automated analytical control of quality of products and systems; quality control of automated chemical analysis; and improvement of capital (accuracy and representativeness), basic (sensitivity, precision, and selectivity), and complementary (rapidity, cost, and personnel factors) analytical features. Several examples are presented to demonstrate the importance of this marriage of convenience in present and future analytical chemistry. 7 refs., 4 figs.

  11. Editor's Highlight: Analysis of the Effects of Cell Stress and Cytotoxicity on In Vitro Assay Activity Across a Diverse Chemical and Assay Space.

    PubMed

    Judson, Richard; Houck, Keith; Martin, Matt; Richard, Ann M; Knudsen, Thomas B; Shah, Imran; Little, Stephen; Wambaugh, John; Woodrow Setzer, R; Kothya, Parth; Phuong, Jimmy; Filer, Dayne; Smith, Doris; Reif, David; Rotroff, Daniel; Kleinstreuer, Nicole; Sipes, Nisha; Xia, Menghang; Huang, Ruili; Crofton, Kevin; Thomas, Russell S

    2016-08-01

    Chemical toxicity can arise from disruption of specific biomolecular functions or through more generalized cell stress and cytotoxicity-mediated processes. Here, responses of 1060 chemicals including pharmaceuticals, natural products, pesticidals, consumer, and industrial chemicals across a battery of 815 in vitro assay endpoints from 7 high-throughput assay technology platforms were analyzed in order to distinguish between these types of activities. Both cell-based and cell-free assays showed a rapid increase in the frequency of responses at concentrations where cell stress/cytotoxicity responses were observed in cell-based assays. Chemicals that were positive on at least 2 viability/cytotoxicity assays within the concentration range tested (typically up to 100 μM) activated a median of 12% of assay endpoints whereas those that were not cytotoxic in this concentration range activated 1.3% of the assays endpoints. The results suggest that activity can be broadly divided into: (1) specific biomolecular interactions against one or more targets (eg, receptors or enzymes) at concentrations below which overt cytotoxicity-associated activity is observed; and (2) activity associated with cell stress or cytotoxicity, which may result from triggering specific cell stress pathways, chemical reactivity, physico-chemical disruption of proteins or membranes, or broad low-affinity non-covalent interactions. Chemicals showing a greater number of specific biomolecular interactions are generally designed to be bioactive (pharmaceuticals or pesticidal active ingredients), whereas intentional food-use chemicals tended to show the fewest specific interactions. The analyses presented here provide context for use of these data in ongoing studies to predict in vivo toxicity from chemicals lacking extensive hazard assessment.

  12. Binding of diverse environmental chemicals with human cytochromes P450 2A13, 2A6, and 1B1 and enzyme inhibition.

    PubMed

    Shimada, Tsutomu; Kim, Donghak; Murayama, Norie; Tanaka, Katsuhiro; Takenaka, Shigeo; Nagy, Leslie D; Folkman, Lindsay M; Foroozesh, Maryam K; Komori, Masayuki; Yamazaki, Hiroshi; Guengerich, F Peter

    2013-04-15

    A total of 68 chemicals including derivatives of naphthalene, phenanthrene, fluoranthene, pyrene, biphenyl, and flavone were examined for their abilities to interact with human P450s 2A13 and 2A6. Fifty-one of these 68 chemicals induced stronger Type I binding spectra (iron low- to high-spin state shift) with P450 2A13 than those seen with P450 2A6, i.e., the spectral binding intensities (ΔAmax/Ks ratio) determined with these chemicals were always higher for P450 2A13. In addition, benzo[c]phenanthrene, fluoranthene, 2,3-dihydroxy-2,3-dihydrofluoranthene, pyrene, 1-hydroxypyrene, 1-nitropyrene, 1-acetylpyrene, 2-acetylpyrene, 2,5,2',5'-tetrachlorobiphenyl, 7-hydroxyflavone, chrysin, and galangin were found to induce a Type I spectral change only with P450 2A13. Coumarin 7-hydroxylation, catalyzed by P450 2A13, was strongly inhibited by 2'-methoxy-5,7-dihydroxyflavone, 2-ethynylnaphthalene, 2'-methoxyflavone, 2-naphththalene propargyl ether, acenaphthene, acenaphthylene, naphthalene, 1-acetylpyrene, flavanone, chrysin, 3-ethynylphenanthrene, flavone, and 7-hydroxyflavone; these chemicals induced Type I spectral changes with low Ks values. On the basis of the intensities of the spectral changes and inhibition of P450 2A13, we classified the 68 chemicals into eight groups based on the order of affinities for these chemicals and inhibition of P450 2A13. The metabolism of chemicals by P450 2A13 during the assays explained why some of the chemicals that bound well were poor inhibitors of P450 2A13. Finally, we compared the 68 chemicals for their abilities to induce Type I spectral changes of P450 2A13 with the Reverse Type I binding spectra observed with P450 1B1: 45 chemicals interacted with both P450s 2A13 and 1B1, indicating that the two enzymes have some similarty of structural features regarding these chemicals. Molecular docking analyses suggest similarities at the active sites of these P450 enzymes. These results indicate that P450 2A13, as well as Family 1 P450

  13. Binding of Diverse Environmental Chemicals with Human Cytochromes P450 2A13, 2A6, and 1B1 and Enzyme Inhibition

    PubMed Central

    Shimada, Tsutomu; Kim, Donghak; Murayama, Norie; Tanaka, Katsuhiro; Takenaka, Shigeo; Nagy, Leslie D.; Folkman, Lindsay M.; Foroozesh, Maryam K.; Komori, Masayuki; Yamazaki, Hiroshi; Guengerich, F. Peter

    2014-01-01

    A total of 68 chemicals including derivatives of naphthalene, phenanthrene, fluoranthene, pyrene, biphenyl, and flavone were examined for their abilities to interact with human P450s 2A13 and 2A6. Fifty-one of these 68 chemicals induced stronger Type I binding spectra (iron low- to high-spin state shift) with P450 2A13 than those seen with P450 2A6, i.e. the spectral binding intensities (ΔAmax/Ks ratio) determined with these chemicals were always higher for P450 2A13. In addition, benzo[c]phenanthrene, fluoranthene, 2,3-dihydroxy-2,3-dihydrofluoranthene, pyrene, 1-hydroxypyrene, 1-nitropyrene, 1-acetylpyrene, 2-acetylpyrene, 2,5,2’,5’-tetrachlorobiphenyl, 7-hydroxyflavone, chrysin, and galangin were found to induce a Type I spectral change only with P450 2A13. Coumarin 7-hydroxylation, catalyzed by P450 2A13, was strongly inhibited by 2’-methoxy-5,7-dihydroxyflavone, 2-ethynylnaphthalene, 2’-methoxyflavone, 2-naphththalene propargyl ether, acenaphthene, acenaphthylene, naphthalene, 1-acetylpyrene, flavanone, chrysin, 3-ethynylphenanthrene, flavone, and 7-hydroxyflavone; these chemicals induced Type I spectral changes with low Ks values. On the basis of the intensities of the spectral changes and inhibition of P450 2A13, we classified the 68 chemicals into eight groups based on the order of affinities for these chemicals and inhibition of P450 2A13. The metabolism of chemicals by P450 2A13 during the assays explained why some of the chemicals that bound well were poor inhibitors of P450 2A13. Finally, we compared the 68 chemicals for their abilities to induce Type I spectral changes of P450 2A13 with the Reverse Type I binding spectra observed with P450 1B1: 45 chemicals interacted with both P450s 2A13 and 1B1, indicating that the two enzymes have some similarty of structural features regarding these chemicals. Molecular docking analyses suggest similarities at the active sites of these P450 enzymes. These results indicate that P450 2A13, as well as Family

  14. Phytochemical diversity drives plant–insect community diversity

    PubMed Central

    Richards, Lora A.; Dyer, Lee A.; Forister, Matthew L.; Smilanich, Angela M.; Dodson, Craig D.; Leonard, Michael D.; Jeffrey, Christopher S.

    2015-01-01

    What are the ecological causes and consequences of variation in phytochemical diversity within and between plant taxa? Despite decades of natural products discovery by organic chemists and research by chemical ecologists, our understanding of phytochemically mediated ecological processes in natural communities has been restricted to studies of either broad classes of compounds or a small number of well-characterized molecules. Until now, no studies have assessed the ecological causes or consequences of rigorously quantified phytochemical diversity across taxa in natural systems. Consequently, hypotheses that attempt to explain variation in phytochemical diversity among plants remain largely untested. We use spectral data from crude plant extracts to characterize phytochemical diversity in a suite of co-occurring plants in the tropical genus Piper (Piperaceae). In combination with 20 years of data focused on Piper-associated insects, we find that phytochemical diversity has a direct and positive effect on the diversity of herbivores but also reduces overall herbivore damage. Elevated chemical diversity is associated with more specialized assemblages of herbivores, and the cascading positive effect of phytochemistry on herbivore enemies is stronger as herbivore diet breadth narrows. These results are consistent with traditional hypotheses that predict positive associations between plant chemical diversity, insect herbivore diversity, and trophic specialization. It is clear from these results that high phytochemical diversity not only enhances the diversity of plant-associated insects but also contributes to the ecological predominance of specialized insect herbivores. PMID:26283384

  15. Phytochemical diversity drives plant-insect community diversity.

    PubMed

    Richards, Lora A; Dyer, Lee A; Forister, Matthew L; Smilanich, Angela M; Dodson, Craig D; Leonard, Michael D; Jeffrey, Christopher S

    2015-09-01

    What are the ecological causes and consequences of variation in phytochemical diversity within and between plant taxa? Despite decades of natural products discovery by organic chemists and research by chemical ecologists, our understanding of phytochemically mediated ecological processes in natural communities has been restricted to studies of either broad classes of compounds or a small number of well-characterized molecules. Until now, no studies have assessed the ecological causes or consequences of rigorously quantified phytochemical diversity across taxa in natural systems. Consequently, hypotheses that attempt to explain variation in phytochemical diversity among plants remain largely untested. We use spectral data from crude plant extracts to characterize phytochemical diversity in a suite of co-occurring plants in the tropical genus Piper (Piperaceae). In combination with 20 years of data focused on Piper-associated insects, we find that phytochemical diversity has a direct and positive effect on the diversity of herbivores but also reduces overall herbivore damage. Elevated chemical diversity is associated with more specialized assemblages of herbivores, and the cascading positive effect of phytochemistry on herbivore enemies is stronger as herbivore diet breadth narrows. These results are consistent with traditional hypotheses that predict positive associations between plant chemical diversity, insect herbivore diversity, and trophic specialization. It is clear from these results that high phytochemical diversity not only enhances the diversity of plant-associated insects but also contributes to the ecological predominance of specialized insect herbivores.

  16. Diversity for chemical composition in a collection of different varietal types of tree tomato (Solanum betaceum Cav.), an Andean exotic fruit.

    PubMed

    Acosta-Quezada, Pablo G; Raigón, María D; Riofrío-Cuenca, Tania; García-Martínez, María D; Plazas, Mariola; Burneo, Juan I; Figueroa, Jorge G; Vilanova, Santiago; Prohens, Jaime

    2015-02-15

    We evaluated 23 tree tomato (Solanum betaceum) accessions from five cultivar groups and one wild relative (Solanum cajanumense) for 26 composition traits. For all traits we found highly significant differences (P<0.001) among the materials studied. The high diversity found within S. betaceum for composition traits was matched by a high diversity within each of the cultivar groups. We found that sucrose and citric acid were the most important soluble sugar and organic acid, respectively, in tree tomato. Fruit in the anthocyanin pigmented (purple) group had a carotenoid content similar to that in the yellow-orange cultivar groups. Total phenolic content was significantly correlated (r=0.8607) with antioxidant activity. Analyses of mineral content showed that tree tomato is a good source of K, Mg, and Cu. Multivariate principal components analysis (PCA) confirmed that an important diversity exists within each cultivar group. The results we have obtained indicate that the high diversity found within the tree tomato could be exploited for selection and breeding for developing the tree tomato as a commercial crop.

  17. Analytical Methodologies for the Determination of Endocrine Disrupting Compounds in Biological and Environmental Samples

    PubMed Central

    Sosa-Ferrera, Zoraida; Mahugo-Santana, Cristina; Santana-Rodríguez, José Juan

    2013-01-01

    Endocrine-disruptor compounds (EDCs) can mimic natural hormones and produce adverse effects in the endocrine functions by interacting with estrogen receptors. EDCs include both natural and synthetic chemicals, such as hormones, personal care products, surfactants, and flame retardants, among others. EDCs are characterised by their ubiquitous presence at trace-level concentrations and their wide diversity. Since the discovery of the adverse effects of these pollutants on wildlife and human health, analytical methods have been developed for their qualitative and quantitative determination. In particular, mass-based analytical methods show excellent sensitivity and precision for their quantification. This paper reviews recently published analytical methodologies for the sample preparation and for the determination of these compounds in different environmental and biological matrices by liquid chromatography coupled with mass spectrometry. The various sample preparation techniques are compared and discussed. In addition, recent developments and advances in this field are presented. PMID:23738329

  18. Analytical and Radiochemistry for Nuclear Forensics

    SciTech Connect

    Steiner, Robert Ernest; Dry, Donald E.; Kinman, William Scott; Podlesak, David; Tandon, Lav

    2015-05-26

    Information about nonproliferation nuclear forensics, activities in forensics at Los Alamos National Laboratory, radio analytical work at LANL, radiochemical characterization capabilities, bulk chemical and materials analysis capabilities, and future interests in forensics interactions.

  19. Physiological and Anatomical Visual Analytics (PAVA) Background

    EPA Pesticide Factsheets

    The need to efficiently analyze human chemical disposition data from in vivo studies or in silico PBPK modeling efforts, and to see complex disposition data in a logical manner, has created a unique opportunity for visual analytics applid to PAD.

  20. Method and apparatus for detecting an analyte

    DOEpatents

    Allendorf, Mark D [Pleasanton, CA; Hesketh, Peter J [Atlanta, GA

    2011-11-29

    We describe the use of coordination polymers (CP) as coatings on microcantilevers for the detection of chemical analytes. CP exhibit changes in unit cell parameters upon adsorption of analytes, which will induce a stress in a static microcantilever upon which a CP layer is deposited. We also describe fabrication methods for depositing CP layers on surfaces.

  1. Understanding Business Analytics

    DTIC Science & Technology

    2015-01-05

    Business Analytics, Decision Analytics, Business Intelligence, Advanced Analytics, Data Science. . . to a certain degree, to label is to limit - if only... Business Analytics. 2004 2006 2008 2010 2012 2014 Figure 1: Google trending of daily searches for various analytic disciplines “The limits of my

  2. Optofluidics in bio-chemical analysis

    NASA Astrophysics Data System (ADS)

    Guo, Yunbo; Fan, Xudong

    2012-01-01

    Optofluidics organically integrates microfluidics and photonics and is an emerging technology in biological and chemical analysis. In this paper, we overview the recent studies in bio-chemical sensing applications of optofluidics. Particularly, we report the research progress in our lab in developing diverse optofluidic devices using two unique configurations: thin-walled capillary based optofluidic ring resonator (OFRR) and multi-hole capillary based optofluidic platforms. The first one has been developed to be OFRR-based label-free biosensor, microfluidic laser based intra-cavity sensors, and on-column optical detectors for micro-gas chromatography (μGC), while the second one has been developed to be optofluidic Fabry-Pérot based label-free biosensor and optofluidic Surface-Enhanced Raman Spectroscopy (SERS) biosensor. All of these devices take advantage of superior fluidic handling capability and high sensitivity, and have been used in detecting various biological and chemical analytes in either liquid or vapor phase.

  3. Microemulsification: an approach for analytical determinations.

    PubMed

    Lima, Renato S; Shiroma, Leandro Y; Teixeira, Alvaro V N C; de Toledo, José R; do Couto, Bruno C; de Carvalho, Rogério M; Carrilho, Emanuel; Kubota, Lauro T; Gobbi, Angelo L

    2014-09-16

    We address a novel method for analytical determinations that combines simplicity, rapidity, low consumption of chemicals, and portability with high analytical performance taking into account parameters such as precision, linearity, robustness, and accuracy. This approach relies on the effect of the analyte content over the Gibbs free energy of dispersions, affecting the thermodynamic stabilization of emulsions or Winsor systems to form microemulsions (MEs). Such phenomenon was expressed by the minimum volume fraction of amphiphile required to form microemulsion (Φ(ME)), which was the analytical signal of the method. Thus, the measurements can be taken by visually monitoring the transition of the dispersions from cloudy to transparent during the microemulsification, like a titration. It bypasses the employment of electric energy. The performed studies were: phase behavior, droplet dimension by dynamic light scattering, analytical curve, and robustness tests. The reliability of the method was evaluated by determining water in ethanol fuels and monoethylene glycol in complex samples of liquefied natural gas. The dispersions were composed of water-chlorobenzene (water analysis) and water-oleic acid (monoethylene glycol analysis) with ethanol as the hydrotrope phase. The mean hydrodynamic diameter values for the nanostructures in the droplet-based water-chlorobenzene MEs were in the range of 1 to 11 nm. The procedures of microemulsification were conducted by adding ethanol to water-oleic acid (W-O) mixtures with the aid of micropipette and shaking. The Φ(ME) measurements were performed in a thermostatic water bath at 23 °C by direct observation that is based on the visual analyses of the media. The experiments to determine water demonstrated that the analytical performance depends on the composition of ME. It shows flexibility in the developed method. The linear range was fairly broad with limits of linearity up to 70.00% water in ethanol. For monoethylene glycol in

  4. Past Planktonic Diversity

    NASA Astrophysics Data System (ADS)

    Rufino, M. M.; Salgueiro, E.; Voelker, A. H. L.; Abrantes, F. F. G.

    2014-12-01

    Planktonic organisms have been extensively used in paleoceanographic studies as proxies for most marine environmental variables (temperature, salinity, currents, frontal zones, upwelling, etc.), both directly by species occurrences and indirectly through particular chemical components produced (e.g. Mg/Ca, stable isotopes, alkanones). In 1965 Stehli pioneered by suggesting the use of planktonic organisms diversity to decipher ancient oceanic circulation, instead of the traditional approaches based on particular indicator species or assemblages composition (transfer functions). The use of species diversity has two main advantages. First, it is not restricted to a temporal epoch where the species existed and second, it does not assume that the species ecology is the same as in the present. In the current work, we compare planktonic organisms diversity on the Atlantic Ocean, obtained from surface samples, with the main satellite measured oceanographic variables, i.e. SST (Sea Surface Temperature), CHL (as an indicator of primary productivity) and the main currents in the area. Three indices were used to quantify diversity: Shannon-Weaver diversity (H), specific richness (S) and Hulbert's probability of interspecific encounter index of species evenness (PIE). Diversity was then modelled spatially using geostatistical tools at two scales: Atlantic Ocean oceanographic scale and the Iberian margin regional scale. The main conclusions will then be used to interpret measured down core diversity, on a paleo perspective. This work will understand how did diversity reacted to major climatic events, and how long it took to recover - system resilience.

  5. Rethinking Diversity.

    ERIC Educational Resources Information Center

    Gordon, Jack

    1992-01-01

    Managing diversity is about coping with unassimilated differences, about building systems and a culture that unite different people in a common pursuit without undermining their diversity. The goal of diversity training is a high performance organization rather than a climate in which no one's feathers are ruffled. (SK)

  6. Rethinking Diversity.

    ERIC Educational Resources Information Center

    1996

    These three papers were presented at a symposium on rethinking diversity in human resource development (HRD) moderated by Neal Chalofsky at the 1996 conference of the Academy of Human Resource Development. "Diversity: A Double-Edged Sword" (Sally F. Angus) presents the notion of work force diversity through two differing perspectives in order to…

  7. Bioinformatics Symposium of the Analytical Division of the American Chemical Society Meeting. Final Technical Report from 03/15/2000 to 03/14/2001 [sample pages of agenda, abstracts, index

    SciTech Connect

    Kennedy, Robert T.

    2000-03-28

    Sparked by the Human Genome Project, biological and biomedical research has become an information science. Information tools are now being generated for proteins, cell modeling, and genomics. The opportunity for analytical chemistry in this new environment is profound. New analytical techniques that can provide the information on genes, SNPs, proteins, protein modifications, cells, and cell chemistry are required. In this symposium, we brought together both informatics experts and leading analytical chemists to discuss this interface. Over 200 people attended this highly successful symposium.

  8. Analytical Chemistry of Nitric Oxide

    PubMed Central

    Hetrick, Evan M.

    2013-01-01

    Nitric oxide (NO) is the focus of intense research, owing primarily to its wide-ranging biological and physiological actions. A requirement for understanding its origin, activity, and regulation is the need for accurate and precise measurement techniques. Unfortunately, analytical assays for monitoring NO are challenged by NO’s unique chemical and physical properties, including its reactivity, rapid diffusion, and short half-life. Moreover, NO concentrations may span pM to µM in physiological milieu, requiring techniques with wide dynamic response ranges. Despite such challenges, many analytical techniques have emerged for the detection of NO. Herein, we review the most common spectroscopic and electrochemical methods, with special focus on the fundamentals behind each technique and approaches that have been coupled with modern analytical measurement tools or exploited to create novel NO sensors. PMID:20636069

  9. Analytical chemistry of nitric oxide.

    PubMed

    Hetrick, Evan M; Schoenfisch, Mark H

    2009-01-01

    Nitric oxide (NO) is the focus of intense research primarily because of its wide-ranging biological and physiological actions. To understand its origin, activity, and regulation, accurate and precise measurement techniques are needed. Unfortunately, analytical assays for monitoring NO are challenged by NO's unique chemical and physical properties, including its reactivity, rapid diffusion, and short half-life. Moreover, NO concentrations may span the picomolar-to-micromolar range in physiological milieus, requiring techniques with wide dynamic response ranges. Despite such challenges, many analytical techniques have emerged for the detection of NO. Herein, we review the most common spectroscopic and electrochemical methods, with a focus on the underlying mechanism of each technique and on approaches that have been coupled with modern analytical measurement tools to create novel NO sensors.

  10. New and emerging analytical techniques for marine biotechnology.

    PubMed

    Burgess, J Grant

    2012-02-01

    Marine biotechnology is the industrial, medical or environmental application of biological resources from the sea. Since the marine environment is the most biologically and chemically diverse habitat on the planet, marine biotechnology has, in recent years delivered a growing number of major therapeutic products, industrial and environmental applications and analytical tools. These range from the use of a snail toxin to develop a pain control drug, metabolites from a sea squirt to develop an anti-cancer therapeutic, and marine enzymes to remove bacterial biofilms. In addition, well known and broadly used analytical techniques are derived from marine molecules or enzymes, including green fluorescence protein gene tagging methods and heat resistant polymerases used in the polymerase chain reaction. Advances in bacterial identification, metabolic profiling and physical handling of cells are being revolutionised by techniques such as mass spectrometric analysis of bacterial proteins. Advances in instrumentation and a combination of these physical advances with progress in proteomics and bioinformatics are accelerating our ability to harness biology for commercial gain. Single cell Raman spectroscopy and microfluidics are two emerging techniques which are also discussed elsewhere in this issue. In this review, we provide a brief survey and update of the most powerful and rapidly growing analytical techniques as used in marine biotechnology, together with some promising examples of less well known earlier stage methods which may make a bigger impact in the future.

  11. Transcription factor-based biosensors enlightened by the analyte

    PubMed Central

    Fernandez-López, Raul; Ruiz, Raul; de la Cruz, Fernando; Moncalián, Gabriel

    2015-01-01

    Whole cell biosensors (WCBs) have multiple applications for environmental monitoring, detecting a wide range of pollutants. WCBs depend critically on the sensitivity and specificity of the transcription factor (TF) used to detect the analyte. We describe the mechanism of regulation and the structural and biochemical properties of TF families that are used, or could be used, for the development of environmental WCBs. Focusing on the chemical nature of the analyte, we review TFs that respond to aromatic compounds (XylS-AraC, XylR-NtrC, and LysR), metal ions (MerR, ArsR, DtxR, Fur, and NikR) or antibiotics (TetR and MarR). Analyzing the structural domains involved in DNA recognition, we highlight the similitudes in the DNA binding domains (DBDs) of these TF families. Opposite to DBDs, the wide range of analytes detected by TFs results in a diversity of structures at the effector binding domain. The modular architecture of TFs opens the possibility of engineering TFs with hybrid DNA and effector specificities. Yet, the lack of a crisp correlation between structural domains and specific functions makes this a challenging task. PMID:26191047

  12. Analytical Methods for Biomass Characterization during Pretreatment and Bioconversion

    SciTech Connect

    Pu, Yunqiao; Meng, Xianzhi; Yoo, Chang Geun; Li, Mi; Ragauskas, Arthur J

    2016-01-01

    Lignocellulosic biomass has been introduced as a promising resource for alternative fuels and chemicals because of its abundance and complement for petroleum resources. Biomass is a complex biopolymer and its compositional and structural characteristics largely vary depending on its species as well as growth environments. Because of complexity and variety of biomass, understanding its physicochemical characteristics is a key for effective biomass utilization. Characterization of biomass does not only provide critical information of biomass during pretreatment and bioconversion, but also give valuable insights on how to utilize the biomass. For better understanding biomass characteristics, good grasp and proper selection of analytical methods are necessary. This chapter introduces existing analytical approaches that are widely employed for biomass characterization during biomass pretreatment and conversion process. Diverse analytical methods using Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR) spectroscopy for biomass characterization are reviewed. In addition, biomass accessibility methods by analyzing surface properties of biomass are also summarized in this chapter.

  13. Diversity of active microbial communities subjected to long-term exposure to chemical contaminants along a 40-year-old sediment core.

    PubMed

    Kaci, Assia; Petit, Fabienne; Fournier, Matthieu; Cécillon, Sébastien; Boust, Dominique; Lesueur, Patrick; Berthe, Thierry

    2016-03-01

    In estuarine ecosystems, metallic and organic contaminants are mainly associated with fine grain sediments which settle on mudflats. Over time, the layers of sediment accumulate and are then transformed by diagenetic processes mainly controlled by microbial activity, recording the history of the estuary's chemical contamination. In an environment of this specific type, we investigated the evolution of the chemical contamination and the structure of both total and active microbial communities, based on PhyloChip analysis of a 4.6-m core corresponding to a 40-year sedimentary record. While the archaeal abundance remained constant along the core, a decrease by one order of magnitude in the bacterial abundance was observed with depth. Both total and active microbial communities were dominated by Proteobacteria, Actinobacteria, and Firmicutes in all sediment samples. Among Proteobacteria, alpha-Proteobacteria dominated both total (from 37 to 60 %) and metabolically active (from 19.7 to 34.6 %) communities, including the Rhizobiales, Rhodobacter, Caulobacterales, and Sphingomonadales orders. Co-inertia analysis revealed a relationship between polycyclic aromatic hydrocarbons, zinc and some polychlorobiphenyls concentrations, and the structure of total and active microbial communities in the oldest and most contaminated sediments (from 1970 to 1975), suggesting that long-term exposure to chemicals shaped the structure of the microbial community.

  14. Chemical and isotopic diversity in basalts dredged from the East Pacific Rise at 10°S, the fossil Galapagos Rise and the Nazca plate

    USGS Publications Warehouse

    Batiza, Rodey; Oestrike, Richard; Futa, Kiyoto

    1982-01-01

    The dredges from the East Pacific Rise at about 10°S recovered unusual transitional, light rare-earth element (LREE) enriched basalts which show a range of fractionation. On the basis of their chemical and isotopic abundances, it is unlikely that the lavas are related by a single simple process of magmatic differentiation. We suggest that the mantle source region of these basalts was chemically and isotopically heterogeneous. The chemistry of LREE-depleted tholeiitic basalt dredged from near the axis of the extinct Galapagos Rise indicates complex petrogenesis and differentiation. The presence of tholeiitic basalts here indicates that unlike the Guadalupe and Mathematician fossil ridges, the Galapagos Rise has not been the site of voluminous post-abandonment alkalic volcanism. Alkalic basalts of picritic bulk composition dredged from an elongate seamount near the Galapagos Rise do not represent liquid compositions. Instead, we suggest that these alkalic liquids contain added olivine and plagioclase xenocrysts. Although most of the samples analyzed are very fresh, a few have been altered. The latter exhibit characteristic chemical and isotopic effects of seawater alteration.

  15. A fundamental study on analyte adsorption onto metallophthalocyanines

    NASA Astrophysics Data System (ADS)

    Tran, Ngoc L.

    A Web of Science search shows that the number of articles found in the literature pertaining to Phthalocyanines has doubled in the last eight years alone in comparison to all previous years. Based on the types of articles found, it is clear that the potential applications for Metal Phthalocyanines (MPcs) are multifaceted. Initially, MPcs were used as blue and green dye products. Subsequent interest in MPcs increased due to its similarities to the biologically relevant porphyrin. More recently, MPcs have been integrated into information storage systems, liquid crystal color displays and as the active material in semiconductor devices. Their diverse electronic properties, chemical and thermal robustness and ease of deposition (spin coating and organic molecular beam epitaxy) make them an attractive and economical candidate for use in chemical sensors. Although the literature contains many studies pertaining to MPcs, most are focused on the applications aspect of the material or on the fundamental understanding of the electronic properties of the Pcs in the absence of an analyte. This dissertation attempts to obtain an atomic level understanding of the fundamental mechanisms in which analytes interact with MPcs.

  16. Analytics for Education

    ERIC Educational Resources Information Center

    MacNeill, Sheila; Campbell, Lorna M.; Hawksey, Martin

    2014-01-01

    This article presents an overview of the development and use of analytics in the context of education. Using Buckingham Shum's three levels of analytics, the authors present a critical analysis of current developments in the domain of learning analytics, and contrast the potential value of analytics research and development with real world…

  17. Let's Talk... Analytics

    ERIC Educational Resources Information Center

    Oblinger, Diana G.

    2012-01-01

    Talk about analytics seems to be everywhere. Everyone is talking about analytics. Yet even with all the talk, many in higher education have questions about--and objections to--using analytics in colleges and universities. In this article, the author explores the use of analytics in, and all around, higher education. (Contains 1 note.)

  18. Strategic planning for waste management: Characterization of chemically and radioactively hazardous waste and treatment, storage, and disposal capabilities for diverse and varied multisite operations

    SciTech Connect

    Jolley, R.L.; Rivera, A.L.; Fox, E.C.; Hyfantis, G.J.; McBrayer, J.F.

    1988-01-01

    Information about current and projected waste generation as well as available treatment, storage, and disposal (TSD) capabilities and needs is crucial for effective, efficient, and safe waste management. This is especially true for large corporations that are responsible for multisite operations involving diverse and complex industrial processes. Such information is necessary not only for day-to-day operations, but also for strategic planning to ensure safe future performance. This paper reports on some methods developed and successfully applied to obtain requisite information and to assist waste management planning at the corporate level in a nationwide system of laboratories and industries. Waste generation and TSD capabilities at selected US Department of Energy (DOE) sites were studied. 1 ref., 2 tabs.

  19. Systematic investigation of ion suppression and enhancement effects of fourteen stable-isotope-labeled internal standards by their native analogues using atmospheric-pressure chemical ionization and electrospray ionization and the relevance for multi-analyte liquid chromatographic/mass spectrometric procedures.

    PubMed

    Remane, Daniela; Wissenbach, Dirk K; Meyer, Markus R; Maurer, Hans H

    2010-04-15

    In clinical and forensic toxicology, multi-analyte procedures are very useful to quantify drugs and poisons of different classes in one run. For liquid chromatographic/tandem mass spectrometric (LC/MS/MS) multi-analyte procedures, often only a limited number of stable-isotope-labeled internal standards (SIL-ISs) are available. If an SIL-IS is used for quantification of other analytes, it must be excluded that the co-eluting native analyte influences its ionization. Therefore, the effect of ion suppression and enhancement of fourteen SIL-ISs caused by their native analogues has been studied. It could be shown that the native analyte concentration influenced the extent of ion suppression and enhancement effects leading to more suppression with increasing analyte concentration especially when electrospray ionization (ESI) was used. Using atmospheric-pressure chemical ionization (APCI), methanolic solution showed mainly enhancement effects, whereas no ion suppression and enhancement effect, with one exception, occurred when plasma extracts were used under these conditions. Such differences were not observed using ESI. With ESI, eleven SIL-ISs showed relevant suppression effects, but only one analyte showed suppression effects when APCI was used. The presented study showed that ion suppression and enhancement tests using matrix-based samples of different sources are essential for the selection of ISs, particularly if used for several analytes to avoid incorrect quantification. In conclusion, only SIL-ISs should be selected for which no suppression and enhancement effects can be observed. If not enough ISs are free of ionization interferences, a different ionization technique should be considered.

  20. General analytical procedure for determination of acidity parameters of weak acids and bases.

    PubMed

    Pilarski, Bogusław; Kaliszan, Roman; Wyrzykowski, Dariusz; Młodzianowski, Janusz; Balińska, Agata

    2015-01-01

    The paper presents a new convenient, inexpensive, and reagent-saving general methodology for the determination of pK a values for components of the mixture of diverse chemical classes weak organic acids and bases in water solution, without the need to separate individual analytes. The data obtained from simple pH-metric microtitrations are numerically processed into reliable pK a values for each component of the mixture. Excellent agreement has been obtained between the determined pK a values and the reference literature data for compounds studied.

  1. The giant cold-water coral mound as a nested microbial/metazoan system: physical, chemical, biological and geological picture (ESF EuroDiversity MiCROSYSTEMS)

    NASA Astrophysics Data System (ADS)

    Henriet, J. P.; Microsystems Team

    2009-04-01

    The MiCROSYSTEMS project under the ESF EUROCORES EuroDiversity scheme is a holistic and multi-scale approach in studying microbial diversity and functionality in a nested microbial/metazoan system, which thrives in deep waters: the giant cold-water coral mound. Studies on prolific cold-water coral sites have been carried out from the canyons of the Bay of Biscay to the fjords of the Norwegian margin, while the Pen Duick carbonate mound province off Morocco developed into a joint natural lab for studying in particular the impact of biogeochemical and microbial processes on modern sedimentary diagenesis within the reef sediments, in complement to the studies on I0DP Exp. 307 cores (Challenger Mound, off Ireland). Major outcomes of this research can be summarized as follows. • IODP Exp. 307 on Challenger Mound had revealed a significant prokaryotic community both within and beneath the carbonate mound. MiCROSYSTEMS unveils a remarkable degree of compartmentalization in such community from the seawater, the coral skeleton surface and mucus to the reef sediments. The occurrence of such multiple and distinct microbial compartments associated with cold-water coral ecosystems promotes opportunities for microbial diversity in the deep ocean. • New cases of co-habitation of cold-water corals and giant deep-water oysters were discovered in the Bay of Biscay, which add a new facet of macrofaunal diversity to cold-water coral reef systems. • The discovery of giant, ancient coral graveyards on the Moroccan mounds not only fuels the debate about natural versus anthropogenic mass extinction, but these open frameworks simultaneously invite for the study of bio-erosion and early diagenesis, in particular organo-mineralization, and of the possible role and significance of these thick, solid rubble patches in 3D mound-building and consolidation. • The assessment of the carbonate budget of a modern cold-water coral mound (Challenger Mound) reveals that only 33 to 40 wt % of

  2. A set up of a modern analytical laboratory for wastewaters from pulp and paper industry.

    PubMed

    Maximova, Natalia; Dahl, Olli

    2007-08-01

    The introduction of analytical techniques allowing rapid, selective, sensitive, and reliable determination of aqueous pollutants is of crucial importance for the protection of the environment. This critical review summarizes the advanced analytical techniques suggested over the last ten years together with already established methods, and evaluates whether they are fit for wastewater quality assessment considering the area of application, interferences, limit of detection, calibration function, and precision. The key parameters of wastewater quality assessment are: total organic carbon (TOC), chemical oxygen demand (COD), biochemical oxygen demand (BOD), organochlorines (AOX), nitrogen, phosphorus, sulfur, and toxicity. Chromatography and capillary electrophoresis, photocatalytic oxidation with semiconductor nanofilms and atomic emission spectrometry, optical fibre sensors and chemiluminescence, amperometric mediated biosensors and microbial fuel cells, respirometry and bioluminescence measurements are just part of the proposed wastewater analyst's toolkit. The diversity of fundamental phenomena and the captivating elegance of interdisciplinary applications involved in the development of wastewater analytical techniques should attract the interest of a wide scientific audience including analytical chemists, chemical physicists, microbiologists and environmentalists. To conclude, we suggest a laboratory set up for the analysis of wastewaters from the pulp and paper industry.

  3. Modeling the effects of type and concentration of organic modifiers, column type and chemical structure of analytes on the retention in reversed phase liquid chromatography using a single model.

    PubMed

    Jouyban, Abolghasem; Soltani, Somaieh; Shayanfar, Ali; Pappa-Louisi, Adriani

    2011-09-16

    A previously proposed model for representing the retention factor (k) of an analyte in mixed solvent mobile phases was extended to calculate the k of different analytes with respect to the nature of analyte, organic modifier, its concentration and type of the stationary phase. The accuracy of the proposed method was evaluated by calculating mean percentage deviation (MPD) as accuracy criterion. The predicted vs. observed plots were also provided as goodness of fit criteria. The developed model prediction capability compared with a number of previous models (i.e. LSER, general LSER and Oscik equation) through MPD and fitting plots. The proposed method provided acceptable predictions with the advantage of modeling the effects of organic modifiers, mobile phase compositions, columns and analytes using a single equation. The accuracy of developed model was checked using the one column and one analyte out cross validation analyses and the results showed that the developed model was able to predict the unknown analyte retention and the analytes retentions on unknown column accurately.

  4. An Investigation into the Physico-chemical Factors Affecting the Abundance and Diversity of Aquatic Insects in Organically Manured Aquadams and Their Utilization by Oreochromis mossambicus (Perciformes: Cichlidae).

    PubMed

    Rapatsa, M M; Moyo, N A G

    2015-08-01

    The interaction between the fish Oreochromis mossambicus (Percifomes: Cichlidae) and aquatic insects after application of chicken, cow, and pig manure was studied in 7,000-liter plastic aquadams. Principal component analysis showed that most of the variation in water quality after application of manure was accounted for by potassium, nitrogen, dissolved oxygen, phosphate, and alkalinity. Canonical correspondence analysis showed that Gyrinidae, Elminidae, Hydrophilidae, Hydraenidae, and Athericidae were associated with high nutrient levels (nitrogen, phosphorus, and potassium) characteristic of the chicken manure. However, the most abundant aquatic insects Gerridae, Notonectidae, and Culicidae were close to the centre of the ordination and not defined by any nutrient gradient. The Shannon-Wiener diversity was highest in the aquadams treated with chicken manure. The most frequently occurring aquatic insects in the diet of O. mossambicus were culicid mosquitoes in all the treatments. However, in the laboratory, Chironomidae were the most preferred because they lacked refuge. Notonectidae and Gerridae were not recorded in the diet of O. mossambicus despite their abundance. This may be because of their anti-predation strategies. Laboratory experiments showed that Notonectidae, Gyrinidae, and Gerridae fed on Chironomidae and Culicidae. This implies that aquatic predatory insects competed for food with O. mossambicus.

  5. Mississippi River flood of 2008: observations of a large freshwater diversion on physical, chemical, and biological characteristics of a shallow estuarine lake.

    PubMed

    White, J R; Fulweiler, R W; Li, C Y; Bargu, S; Walker, N D; Twilley, R R; Green, S E

    2009-08-01

    High nitrogen (N) loading to coastal aquatic systems can be expressed as increased algal production and subsequent low dissolved oxygen. In April, 2008, predictions for extreme flood stage for the Lower Mississippi River triggered the opening of the Bonnet Carré Spillway, a major release valve for the river. The spillway diverted approximately 8 km3 of water over one month of operation into Lake Pontchartrain with a concomitant 10000 t of NO3-N. Satellite imagery, physical, water quality, and chlorophyll a (chl a) measurements show that the Mississippi River plume mixed with < 40% of the lake during this time, and much of the nutrient load was transported to the coastal ocean. Nitrate, dissolved reactive phosphorus (P), and dissolved silica (Si) concentrations were 4.8, 5.0, and 3.2 times higher, respectively, within the river plume when compared with those of the lake water. Despite the high nutrient concentrations within the river plume, phytoplankton biomass, evidenced by chl a concentrations, was low. Much of the nutrient load appeared to bypass the lake and was transported to the coastal ocean during the opening of the diversion. The potential removal of a total of 7.6% of the N load from the Mississippi River during the one month of flood level flow may have been a contributing factor in the lower than predicted hypoxia zone off the Louisiana coast during the summer of 2008.

  6. Diverse animal models to examine potential role(s) and mechanism of endocrine disrupting chemicals on the tumor progression and prevention: Do they have tumorigenic or anti-tumorigenic property?

    PubMed Central

    Park, Min-Ah; Hwang, Kyung-A

    2011-01-01

    Acting as hormone mimics or antagonists in the interaction with hormone receptors, endocrine disrupting chemicals (EDCs) have the potentials of disturbing the endocrine system in sex steroid hormone-controlled organs and tissues. These effects may lead to the disruption of major regulatory mechanisms, the onset of developmental disorders, and carcinogenesis. Especially, among diverse EDCs, xenoestrogens such as bisphenol A, dioxins, and di(2-ethylhexyl)phthalate, have been shown to activate estrogen receptors (ERs) and to modulate cellular functions induced by ERs. Furthermore, they appear to be closely related with carcinogenicity in estrogen-dependant cancers, including breast, ovary, and prostate cancers. In in vivo animal models, prenatal exposure to xenoestrogens changed the development of the mouse reproductive organs and increased the susceptibility to further carcinogenic exposure and tumor occurence in adults. Unlike EDCs, which are chemically synthesized, several phytoestrogens such as genistein and resveratrol showed chemopreventive effects on specific cancers by contending with ER binding and regulating normal ER action in target tissues of mice. These results support the notion that a diet containing high levels of phytoestrogens can have protective effects on estrogen-related diseases. In spite of the diverse evidences of EDCs and phytoestrogens on causation and prevention of estrogen-dependant cancers provided in this article, there are still disputable questions about the dose-response effect of EDCs or chemopreventive potentials of phytoestrogens. As a wide range of EDCs including phytoestrogens have been remarkably increasing in the environment with the rapid growth in our industrial society and more closely affecting human and wildlife, the potential risks of EDCs in endocrine disruption and carcinogenesis are important issues and needed to be verified in detail. PMID:22232634

  7. Molecular mechanism(s) of endocrine-disrupting chemicals and their potent oestrogenicity in diverse cells and tissues that express oestrogen receptors.

    PubMed

    Lee, Hye-Rim; Jeung, Eui-Bae; Cho, Myung-Haing; Kim, Tae-Hee; Leung, Peter C K; Choi, Kyung-Chul

    2013-01-01

    Endocrine-disrupting chemicals (EDCs) are natural or synthetic compounds present in the environment which can interfere with hormone synthesis and normal physiological functions of male and female reproductive organs. Most EDCs tend to bind to steroid hormone receptors including the oestrogen receptor (ER), progesterone receptor (PR) and androgen receptor (AR). As EDCs disrupt the actions of endogenous hormones, they may induce abnormal reproduction, stimulation of cancer growth, dysfunction of neuronal and immune system. Although EDCs represent a significant public health concern, there are no standard methods to determine effect of EDCs on human beings. The mechanisms underlying adverse actions of EDC exposure are not clearly understood. In this review, we highlighted the toxicology of EDCs and its effect on human health, including reproductive development in males and females as shown in in vitro and in vivo models. In addition, this review brings attention to the toxicity of EDCs via interaction of genomic and non-genomic signalling pathways through hormone receptors.

  8. Diverse pathways of epithelial mesenchymal transition related with cancer progression and metastasis and potential effects of endocrine disrupting chemicals on epithelial mesenchymal transition process.

    PubMed

    Lee, Hae-Miru; Hwang, Kyung-A; Choi, Kyung-Chul

    2016-12-29

    Endocrine disrupting chemicals (EDCs) are natural or synthetic compounds that interfere with normal functions of natural hormones in the body, leading to a disruption of the endocrine system. Specifically, EDCs have the potential to cause formation of several hormone-dependent cancers, including breast, ovarian, and prostate cancers. Epithelial mesenchymal transition (EMT) process by which epithelial cells lose their cell polarity and cell-cell adhesion and acquire mesenchymal phenotype is closely associated with malignant transformation and the initiation of cancer metastasis. As a key epithelial marker responsible for adherens junction, E-cadherin enables the cells to maintain epithelial phenotypes. EMT event is induced by E-cadherin loss which can be carried out by many transcription factors (TFs), including Snail, Slug, ZEB1, ZEB2, Kruppel-like factor 8 (KLF8), and Twist. N-cadherin, fibronectin, and vimentin are mesenchymal markers needed for cellular migration. The EMT process is regulated by several signaling pathways mediated by transforming growth factor β (TGF-β), Wnt-β-catenin, Notch, Hedgehog, and receptor tyrosine kinases. In the present article, we reviewed the current understanding of cancer progression effects of synthetic chemical EDCs such as bisphenol A (BPA), phthalates, tetrachlorodibenzo-p-dioxin (TCDD), and triclosan by focusing their roles in the EMT process. Collectively, the majority of previous studies revealed that BPA, phthalates, TCDD, and triclosan have the potential to induce cancer metastasis through regulating EMT markers and migration via several signaling pathways associated with the EMT program. Therefore, it is considered that the exposure to these EDCs can increase the risk aggravating the disease for the patients suffering cancer and that more regulations about the use of these EDCs are needed.

  9. Multimedia Analysis plus Visual Analytics = Multimedia Analytics

    SciTech Connect

    Chinchor, Nancy; Thomas, James J.; Wong, Pak C.; Christel, Michael; Ribarsky, Martin W.

    2010-10-01

    Multimedia analysis has focused on images, video, and to some extent audio and has made progress in single channels excluding text. Visual analytics has focused on the user interaction with data during the analytic process plus the fundamental mathematics and has continued to treat text as did its precursor, information visualization. The general problem we address in this tutorial is the combining of multimedia analysis and visual analytics to deal with multimedia information gathered from different sources, with different goals or objectives, and containing all media types and combinations in common usage.

  10. Methodological Adaptations for Reliable Measurement of Radium and Radon Isotopes in Hydrothermal Fluids of Extreme Chemical Diversity in Yellowstone National Park, Wyoming, USA

    NASA Astrophysics Data System (ADS)

    Role, A.; Sims, K. W. W.; Scott, S. R.; Lane-Smith, D. R.

    2015-12-01

    To quantitatively model fluid residence times, water-rock-gas interactions, and fluid flow rates in the Yellowstone (YS) hydrothermal system we are measuring short-lived isotopes of Ra (228Ra, 226Ra, 224Ra, 223Ra) and Rn (222Rn, and 220Rn) in hydrothermal fluids and gases. While these isotopes have been used successfully in investigations of water residence times, mixing, and groundwater discharge in oceanic, coastal and estuarine environments, the well-established techniques for measuring Ra and Rn isotopes were developed for seawater and dilute groundwaters which have near neutral pH, moderate temperatures, and a limited range of chemical composition. Unfortunately, these techniques, as originally developed are not suitable for the extreme range of compositions found in YS waters, which have pH ranging from <1 - 10, Eh -.208 to .700 V, water temperatures from ambient to 93 degree C, and high dissolved CO2 concentrations. Here we report on our refinements of these Ra and Rn methods for the extreme conditions found in YS. Our methodologies are now enabling us to quantitatively isolate Ra from fluids that cover a large range of chemical compositions and conduct in-situ Rn isotope measurements that accommodate variable temperatures and high CO2 (Lane-Smith and Sims, 2013, Acta Geophys. 61). These Ra and Rn measurements are now allowing us to apply simple models to quantify hot spring water residence times and aquifer to surface travel times. (224Ra/223Ra) calculations provide estimates of water-rock reaction zone to discharge zone of 4 to 14 days for Yellowstone hot springs and (224Ra/228Ra) shallow aquifer to surface travel times from 2 to 7 days. Further development of more sophisticated models that take into account water-rock-gas reactions and water mixing (shallow groundwater, surface run-off, etc.) will allow us to estimate the timescales of these processes more accurately and thus provide a heretofore-unknown time component to the YS hydrothermal system.

  11. Analytical Challenges in Biotechnology.

    ERIC Educational Resources Information Center

    Glajch, Joseph L.

    1986-01-01

    Highlights five major analytical areas (electrophoresis, immunoassay, chromatographic separations, protein and DNA sequencing, and molecular structures determination) and discusses how analytical chemistry could further improve these techniques and thereby have a major impact on biotechnology. (JN)

  12. Molecular mechanism(s) of endocrine-disrupting chemicals and their potent oestrogenicity in diverse cells and tissues that express oestrogen receptors

    PubMed Central

    Lee, Hye-Rim; Jeung, Eui-Bae; Cho, Myung-Haing; Kim, Tae-Hee; Leung, Peter C K; Choi, Kyung-Chul

    2013-01-01

    Endocrine-disrupting chemicals (EDCs) are natural or synthetic compounds present in the environment which can interfere with hormone synthesis and normal physiological functions of male and female reproductive organs. Most EDCs tend to bind to steroid hormone receptors including the oestrogen receptor (ER), progesterone receptor (PR) and androgen receptor (AR). As EDCs disrupt the actions of endogenous hormones, they may induce abnormal reproduction, stimulation of cancer growth, dysfunction of neuronal and immune system. Although EDCs represent a significant public health concern, there are no standard methods to determine effect of EDCs on human beings. The mechanisms underlying adverse actions of EDC exposure are not clearly understood. In this review, we highlighted the toxicology of EDCs and its effect on human health, including reproductive development in males and females as shown in in vitro and in vivo models. In addition, this review brings attention to the toxicity of EDCs via interaction of genomic and non-genomic signalling pathways through hormone receptors. PMID:23279634

  13. Sensors for detecting analytes in fluids

    NASA Technical Reports Server (NTRS)

    Lewis, Nathan S. (Inventor); Severin, Erik (Inventor)

    1998-01-01

    Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.

  14. Sensors for detecting analytes in fluids

    NASA Technical Reports Server (NTRS)

    Lewis, Nathan S. (Inventor); Severin, Erik (Inventor)

    2001-01-01

    Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.

  15. Sensors for detecting analytes in fluids

    NASA Technical Reports Server (NTRS)

    Lewis, Nathan S. (Inventor); Severin, Erik (Inventor)

    1999-01-01

    Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.

  16. Sensor arrays for detecting analytes in fluids

    NASA Technical Reports Server (NTRS)

    Lewis, Nathan S. (Inventor); Freund, Michael S. (Inventor)

    1996-01-01

    Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g. electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance. Variability in chemical sensitivity from sensor to sensor is provided by qualitatively or quantitatively varying the composition of the conductive and/or nonconductive regions. An electronic nose for detecting an analyte in a fluid may be constructed by using such arrays in conjunction with an electrical measuring device electrically connected to the conductive elements of each sensor.

  17. Analyticity without Differentiability

    ERIC Educational Resources Information Center

    Kirillova, Evgenia; Spindler, Karlheinz

    2008-01-01

    In this article we derive all salient properties of analytic functions, including the analytic version of the inverse function theorem, using only the most elementary convergence properties of series. Not even the notion of differentiability is required to do so. Instead, analytical arguments are replaced by combinatorial arguments exhibiting…

  18. Cyclodextrins in analytical chemistry: host-guest type molecular recognition.

    PubMed

    Szente, Lajos; Szemán, Julianna

    2013-09-03

    Cyclodextrins are utilized in many diverse fields of analytical chemistry, due to their propensity to form reversible inclusion complexes and recognize analytes selectively. This Feature shows how these nanocavities can serve analysts in sample preparation, sensitivity and selectivity improvement, enantio-separation, creating single-molecule sensors, and automatizing DNA sequencing.

  19. Insight and Action Analytics: Three Case Studies to Consider

    ERIC Educational Resources Information Center

    Milliron, Mark David; Malcolm, Laura; Kil, David

    2014-01-01

    Civitas Learning was conceived as a community of practice, bringing together forward-thinking leaders from diverse higher education institutions to leverage insight and action analytics in their ongoing efforts to help students learn well and finish strong. We define insight and action analytics as drawing, federating, and analyzing data from…

  20. Spatial Analytic Interfaces: Spatial User Interfaces for In-Situ Visual Analytics.

    PubMed

    Ens, Barrett; Irani, Pourang

    2016-03-18

    As wearable devices gain acceptance, we ask "What do user interfaces look like in a post-smartphone world?" and "Can these future interfaces support sophisticated interactions in a mobile context?" In stark contrast to the micro-interactions of current wearable interfaces lies visual analytics. A hallmark of such platforms is the ability to simultaneously view multiple linked visualizations of diverse datasets. We draw from visual analytic concepts to address the growing need of individuals to manage information on personal devices. We propose Spatial Analytic Interfaces to leverage the benefits of spatial interaction to enable everyday visual analytic tasks to be performed in-situ, at the most beneficial place and time. We explore the possibilities for such interfaces using head-worn display technology, to integrate multiple information views into the user's physical environment. We discuss current developments and propose research goals for the successful development of SUI for in-situ visual analytics.

  1. Analytical Plan for Roman Glasses

    SciTech Connect

    Strachan, Denis M.; Buck, Edgar C.; Mueller, Karl T.; Schwantes, Jon M.; Olszta, Matthew J.; Thevuthasan, Suntharampillai; Heeren, Ronald M.

    2011-01-01

    Roman glasses that have been in the sea or underground for about 1800 years can serve as the independent “experiment” that is needed for validation of codes and models that are used in performance assessment. Two sets of Roman-era glasses have been obtained for this purpose. One set comes from the sunken vessel the Iulia Felix; the second from recently excavated glasses from a Roman villa in Aquileia, Italy. The specimens contain glass artifacts and attached sediment or soil. In the case of the Iulia Felix glasses quite a lot of analytical work has been completed at the University of Padova, but from an archaeological perspective. The glasses from Aquileia have not been so carefully analyzed, but they are similar to other Roman glasses. Both glass and sediment or soil need to be analyzed and are the subject of this analytical plan. The glasses need to be analyzed with the goal of validating the model used to describe glass dissolution. The sediment and soil need to be analyzed to determine the profile of elements released from the glass. This latter need represents a significant analytical challenge because of the trace quantities that need to be analyzed. Both pieces of information will yield important information useful in the validation of the glass dissolution model and the chemical transport code(s) used to determine the migration of elements once released from the glass. In this plan, we outline the analytical techniques that should be useful in obtaining the needed information and suggest a useful starting point for this analytical effort.

  2. Chemical Characterization and Quality Control for an Adhesive.

    DTIC Science & Technology

    ADHESIVES, *IDENTIFICATION, *CHEMICAL ANALYSIS, *QUALITY CONTROL, PHYSICOCHEMICAL PROPERTIES, ACCEPTANCE TESTS, CLASSIFICATION, VIABILITY, TEST METHODS, ANALYTICAL CHEMISTRY, PROCESSING, PRODUCTION CONTROL , AIRCRAFT .

  3. Analytical Chemistry in Russia.

    PubMed

    Zolotov, Yuri

    2016-09-06

    Research in Russian analytical chemistry (AC) is carried out on a significant scale, and the analytical service solves practical tasks of geological survey, environmental protection, medicine, industry, agriculture, etc. The education system trains highly skilled professionals in AC. The development and especially manufacturing of analytical instruments should be improved; in spite of this, there are several good domestic instruments and other satisfy some requirements. Russian AC has rather good historical roots.

  4. Science Update: Analytical Chemistry.

    ERIC Educational Resources Information Center

    Worthy, Ward

    1980-01-01

    Briefly discusses new instrumentation in the field of analytical chemistry. Advances in liquid chromatography, photoacoustic spectroscopy, the use of lasers, and mass spectrometry are also discussed. (CS)

  5. Discovering Diversity.

    ERIC Educational Resources Information Center

    Manner, Barbara M.; Hattler, Jean Anne

    2000-01-01

    Introduces a preservice teacher field trip to the rain forests and coastal areas. This experience develops an awareness for different cultures among preservice teachers by experiencing biological and cultural diversity in Costa Rica. Presents students' own ideas on this experience. (YDS)

  6. Diversity's Calling

    ERIC Educational Resources Information Center

    Cooper, Kenneth J.

    2011-01-01

    This article discusses how a Harvard-educated scholar of English and poetry, Dr. M. Lee Pelton puts a prominent face on changes that are underway at Boston's Emerson College. Faced with a public controversy over its limited faculty diversity, Emerson College has responded with a spate of hirings and promotions of minorities, capped by the…

  7. PLANT DIVERSITY

    EPA Science Inventory

    Habitat change statistics and species-area curves were used to estimate the effects of alternative future scenarios for agriculture on plant diversity in Iowa farmlands. Study areas were two watersheds in central Iowa of about 50 and 90 square kilometers, respectively. Future s...

  8. Generational diversity.

    PubMed

    Kramer, Linda W

    2010-01-01

    Generational diversity has proven challenges for nurse leaders, and generational values may influence ideas about work and career planning. This article discusses generational gaps, influencing factors and support, and the various generational groups present in today's workplace as well as the consequences of need addressing these issues. The article ends with a discussion of possible solutions.

  9. Analytical model of Europa's O2 exosphere

    NASA Astrophysics Data System (ADS)

    Milillo, Anna; Plainaki, Christina; De Angelis, Elisabetta; Mangano, Valeria; Massetti, Stefano; Mura, Alessandro; Orsini, Stefano; Rispoli, Rosanna

    2016-10-01

    The origin of the exosphere of Europa is its water ice surface. The existing exosphere models, assuming either a collisionless environment (simple Monte Carlo techniques) or a kinetic approach (Direct Monte Carlo Method) both predict that the major constituent of the exosphere is molecular oxygen. Specifically, O2 is generated at the surface through radiolysis and chemical interactions of the water dissociation products. The non-escaping O2 molecules circulate around the moon impacting the surface several times, due to their long lifetime and due to their non- sticking, suffering thermalization to the surface temperature after each impact. In fact, the HST observations of the O emission lines proved the presence of an asymmetric atomic Oxygen distribution, related to a thin asymmetric molecular Oxygen atmosphere. The existing Monte Carlo models are not easily applicable as input of simulations devoted to the study of the plasma interactions with the moon. On the other hand, the simple exponential density profiles cannot well depict the higher temperature/higher altitudes component originating by radiolysis. It would thus be important to have a suitable and user-friendly model able to describe the major exospheric characteristics to use as a tool. This study presents an analytical 3D model that is able to describe the molecular Oxygen exosphere by reproducing the two-component profiles and the asymmetries due to diverse configurations among Europa, Jupiter and the Sun. This model is obtained by a non-linear fit procedure of the EGEON Monte Carlo model (Plainaki et al. 2013) to a Chamberlain density profile. Different parameters of the model are able to describe various exosphere properties thus allowing a detailed investigation of the exospheric characteristics. As an example a discussion on the exospheric temperatures in different configurations and space regions is given.

  10. Outlier Detection through Bipartite Visual Analytics.

    PubMed

    Bhavnani, Suresh K; Drake, Justin A; Dang, Bryant; Vishweswaran, Shyam

    2013-01-01

    A critical goal of outlier detection is to determine whether an outlying value was caused by experimental/human error, or by natural biological diversity. However, because univariate or multivariate methods (e.g., box plots and principle component analysis) typically used for outlier detection use unipartite representations, they cannot distinguish whether outliers across a set of variables represent, for example, a single patient or different patients. Here we propose a bipartite visual analytical approach to outlier detection, and demonstrate its usefulness for identifying complex bipartite outliers in a dataset of rickettsioses patients, which enabled domain experts to determine whether the outliers were caused by errors, or by biological diversity.

  11. ANALYTICAL TOOLS FOR GROUNDWATER POLLUTION ASSESSMENT

    EPA Science Inventory

    This paper deals with the development of analytical screening-exposure models (indices) and their potential application to regulate the use of hazardous chemicals and the design of groundwater buffer strips. The indices describe the leaching of solutes below the root zone (mass f...

  12. Signals: Applying Academic Analytics

    ERIC Educational Resources Information Center

    Arnold, Kimberly E.

    2010-01-01

    Academic analytics helps address the public's desire for institutional accountability with regard to student success, given the widespread concern over the cost of higher education and the difficult economic and budgetary conditions prevailing worldwide. Purdue University's Signals project applies the principles of analytics widely used in…

  13. Extreme Scale Visual Analytics

    SciTech Connect

    Wong, Pak C.; Shen, Han-Wei; Pascucci, Valerio

    2012-05-08

    Extreme-scale visual analytics (VA) is about applying VA to extreme-scale data. The articles in this special issue examine advances related to extreme-scale VA problems, their analytical and computational challenges, and their real-world applications.

  14. Learning Analytics Considered Harmful

    ERIC Educational Resources Information Center

    Dringus, Laurie P.

    2012-01-01

    This essay is written to present a prospective stance on how learning analytics, as a core evaluative approach, must help instructors uncover the important trends and evidence of quality learner data in the online course. A critique is presented of strategic and tactical issues of learning analytics. The approach to the critique is taken through…

  15. Analytical mass spectrometry

    SciTech Connect

    Not Available

    1990-01-01

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  16. Analytical mass spectrometry. Abstracts

    SciTech Connect

    Not Available

    1990-12-31

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  17. Steviol glycosides: chemical diversity, metabolism, and function.

    PubMed

    Ceunen, Stijn; Geuns, Jan M C

    2013-06-28

    Steviol glycosides are a group of highly sweet diterpene glycosides discovered in only a few plant species, most notably the Paraguayan shrub Stevia rebaudiana. During the past few decades, the nutritional and pharmacological benefits of these secondary metabolites have become increasingly apparent. While these properties are now widely recognized, many aspects related to their in vivo biochemistry and metabolism and their relationship to the overall plant physiology of S. rebaudiana are not yet understood. Furthermore, the large size of the steviol glycoside pool commonly found within S. rebaudiana leaves implies a significant metabolic investment and poses questions regarding the benefits S. rebaudiana might gain from their accumulation. The current review intends to thoroughly discuss the available knowledge on these issues.

  18. Quo vadis, analytical chemistry?

    PubMed

    Valcárcel, Miguel

    2016-01-01

    This paper presents an open, personal, fresh approach to the future of Analytical Chemistry in the context of the deep changes Science and Technology are anticipated to experience. Its main aim is to challenge young analytical chemists because the future of our scientific discipline is in their hands. A description of not completely accurate overall conceptions of our discipline, both past and present, to be avoided is followed by a flexible, integral definition of Analytical Chemistry and its cornerstones (viz., aims and objectives, quality trade-offs, the third basic analytical reference, the information hierarchy, social responsibility, independent research, transfer of knowledge and technology, interfaces to other scientific-technical disciplines, and well-oriented education). Obsolete paradigms, and more accurate general and specific that can be expected to provide the framework for our discipline in the coming years are described. Finally, the three possible responses of analytical chemists to the proposed changes in our discipline are discussed.

  19. High-throughput analytical techniques for determination of residues of 653 multiclass pesticides and chemical pollutants in tea, Part II: comparative study of extraction efficiencies of three sample preparation techniques.

    PubMed

    Fan, Chun-Lin; Chang, Qiao-Ying; Pang, Guo-Fang; Li, Zeng-Yin; Kang, Jian; Pan, Guo-Qing; Zheng, Shu-Zhan; Wang, Wen-Wen; Yao, Cui-Cui; Ji, Xin-Xin

    2013-01-01

    This paper reports a study of the extraction efficiency for the multiresidue pesticides and chemical pollutants in tea with three methods over three stages. Method 1 adopts the Pang et al. approach: the targets were extracted with 1% acetic acid in acetonitrile and cleaned up with a Cleanert TPT SPE cartridge; Method 2 adopts the QuEChERS approach: the targets were cleaned up dispersively with graphitized carbon and primary-secondary amine (PSA) sorbent; Method 3 adopts the relatively commonly used approach of hydration for solid samples, with tea hydrated before being extracted through salting out with acetonitrile and the cleanup procedures identical to those of Method 1. The three stages comprised two phases of comparative tests on spike recoveries of 201 pesticides and chemical pollutants from different teas and a third phase on determination of the content of the 201 pesticides and chemical pollutants from aged tea samples. In stages I and II, test results of the spike recoveries of 201 pesticides and chemical pollutants demonstrated that 91.4% of the pesticide and chemical pollutant recoveries fell within the range of 70-110%, and 93.2% of the pesticides and chemical pollutants had RSD < 15%, with no marked difference obtained by Method 1 and Method 2 regardless of whether it was green tea or woolong tea, or GC/MS or GC/MS/MS was used for analysis. For pigment removal, Method 1 was superior to Method 2; in terms of easy operation, Method 2 outweighed Method 1. However, Method 3 obtained relatively low recoveries, with 94% of pesticide and chemical pollutant recoveries less than 70%, which proved that Method 3 was not applicable to the determination of multiresidue pesticides and chemical pollutants in tea. Stage III made a comparison of Method 1 and Method 2 for the extraction efficiency of pesticides and chemical pollutants in 165-day-aged samples of green and woolong tea. Test results showed that 94% of the pesticide and chemical pollutant content in the

  20. Predictive analytics and child protection: constraints and opportunities.

    PubMed

    Russell, Jesse

    2015-08-01

    This paper considers how predictive analytics might inform, assist, and improve decision making in child protection. Predictive analytics represents recent increases in data quantity and data diversity, along with advances in computing technology. While the use of data and statistical modeling is not new to child protection decision making, its use in child protection is experiencing growth, and efforts to leverage predictive analytics for better decision-making in child protection are increasing. Past experiences, constraints and opportunities are reviewed. For predictive analytics to make the most impact on child protection practice and outcomes, it must embrace established criteria of validity, equity, reliability, and usefulness.

  1. Chemical sensor system

    DOEpatents

    Darrow, Christopher B.; Satcher, Jr., Joe H.; Lane, Stephen M.; Lee, Abraham P.; Wang, Amy W.

    2002-01-01

    An implantable chemical sensor system for medical applications is described which permits selective recognition of an analyte using an expandable biocompatible sensor, such as a polymer, that undergoes a dimensional change in the presence of the analyte. The expandable polymer is incorporated into an electronic circuit component that changes its properties (e.g., frequency) when the polymer changes dimension. As the circuit changes its characteristics, an external interrogator transmits a signal transdermally to the transducer, and the concentration of the analyte is determined from the measured changes in the circuit. This invention may be used for minimally invasive monitoring of blood glucose levels in diabetic patients.

  2. Visual Analytics 101

    SciTech Connect

    Scholtz, Jean; Burtner, Edwin R.; Cook, Kristin A.

    2016-06-13

    This course will introduce the field of Visual Analytics to HCI researchers and practitioners highlighting the contributions they can make to this field. Topics will include a definition of visual analytics along with examples of current systems, types of tasks and end users, issues in defining user requirements, design of visualizations and interactions, guidelines and heuristics, the current state of user-centered evaluations, and metrics for evaluation. We encourage designers, HCI researchers, and HCI practitioners to attend to learn how their skills can contribute to advancing the state of the art of visual analytics

  3. The chemical ecology of cyanobacteria

    PubMed Central

    Leão, Pedro N.; Engene, Niclas; Antunes, Agostinho; Gerwick, William H.; Vasconcelos, Vitor

    2014-01-01

    This review covers the literature on the chemically mediated ecology of cyanobacteria, including ultraviolet radiation protection, feeding-deterrence, allelopathy, resource competition, and signalling. To highlight the chemical and biological diversity of this group of organisms, evolutionary and chemotaxonomical studies are presented. Several technologically relevant aspects of cyanobacterial chemical ecology are also discussed. PMID:22237837

  4. Incorporating Information Literacy Skills into Analytical Chemistry: An Evolutionary Step

    ERIC Educational Resources Information Center

    Walczak, Mary M.; Jackson, Paul T.

    2007-01-01

    The American Chemical Society (ACS) has recently decided to incorporate various information literacy skills for teaching analytical chemistry to the students. The methodology has been found to be extremely effective, as it provides better understanding to the students.

  5. Analytical techniques: A compilation

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A compilation, containing articles on a number of analytical techniques for quality control engineers and laboratory workers, is presented. Data cover techniques for testing electronic, mechanical, and optical systems, nondestructive testing techniques, and gas analysis techniques.

  6. Sensor arrays for detecting analytes in fluids

    NASA Technical Reports Server (NTRS)

    Lewis, Nathan S. (Inventor); Freund, Michael S. (Inventor)

    2000-01-01

    A sensor array for detecting an analyte in a fluid, comprising at least first and second chemically sensitive resistors electrically connected to an electrical measuring apparatus, wherein each of the chemically sensitive resistors comprises a mixture of nonconductive material and a conductive material. Each resistor provides an electrical path through the mixture of nonconductive material and the conductive material. The resistors also provide a difference in resistance between the conductive elements when contacted with a fluid comprising an analyte at a first concentration, than when contacted with an analyte at a second different concentration. A broad range of analytes can be detected using the sensors of the present invention. Examples of such analytes include, but are not limited to, alkanes, alkenes, alkynes, dienes, alicyclic hydrocarbons, arenes, alcohols, ethers, ketones, aldehydes, carbonyls, carbanions, polynuclear aromatics, organic derivatives, biomolecules, sugars, isoprenes, isoprenoids and fatty acids. Moreover, applications for the sensors of the present invention include, but are not limited to, environmental toxicology, remediation, biomedicine, material quality control, food monitoring and agricultural monitoring.

  7. Gold-on-Polymer-Based Sensing Films for Detection of Organic and Inorganic Analytes in the Air

    NASA Technical Reports Server (NTRS)

    Manatt, Kenneth; Homer, Margie; Ryan, Margaret; Kisor, Adam; Shevade, Abhijit; Jewell, April; Zhou, Hanying

    2008-01-01

    A document discusses gold-on-polymer as one of the novel sensor types developed for part of the sensor development task. Standard polymer-carbon composite sensors used in the JPL Electronic Nose (ENose) have been modified by evaporating 15 nm of metallic gold on the surface. These sensors have been shown to respond to alcohols, aromatics, ammonia, sulfur dioxide, and elemental mercury in the parts-per-million and parts-per-billion concentration ranges in humidified air. The results have shown good sensitivity of these films operating under mild conditions (operating temperatures 23-28 C and regeneration temperature up to 40 C). This unique sensor combines the diversity of polymer sensors for chemical sensing with their response to a wide variety of analytes with the specificity of a gold sensor that shows strong reaction/binding with selected analyte types, such as mercury or sulfur.

  8. Chemical Functionalization of Graphene Family Members

    NASA Astrophysics Data System (ADS)

    Vacchi, Isabella Anna; Ménard-Moyon, Cécilia; Bianco, Alberto

    2017-01-01

    Thanks to their outstanding physicochemical properties, graphene and its derivatives are interesting nanomaterials with a high potential in several fields. Graphene, graphene oxide, and reduced graphene oxide, however, differ partially in their characteristics due to their diverse surface composition. Those differences influence the chemical reactivity of these materials. In the following chapter the reactivity and main functionalization reactions performed on graphene, graphene oxide, and reduced graphene oxide are discussed. A part is also dedicated to the main analytical techniques used for characterization of these materials. Functionalization of graphene and its derivatives is highly important to modulate their characteristics and design graphene-based conjugates with novel properties. Functionalization can be covalent by forming strong and stable bonds with the graphene surface, or non-covalent via π-π, electrostatic, hydrophobic, and/or van der Waals interactions. Both types of functionalization are currently exploited.

  9. Ternary complexes in analytical chemistry.

    PubMed

    Babko, A K

    1968-08-01

    Reactions between a complex AB and a third component C do not always proceed by a displacement mechanism governed by the energy difference of the chemical bonds A-B and A-C. The third component often becomes part of the complex, forming a mixed co-ordination sphere or ternary complex. The properties of this ternary complex ABC are not additive functions of the properties of AB and AC. Such reactions are important in many methods in analytical chemistry, particularly in photometric analysis, extractive separation, masking, etc. The general properties of the four basic types of ternary complex are reviewed and examples given. The four types comprise the systems (a) metal ion, electronegative ligand, organic base, (b) one metal ion, two different electronegative ligands, (c) ternary heteropoly acids, and (d) two different metal ions, one ligand.

  10. Blood and Diversity

    MedlinePlus

    ... Blood > Blood and Diversity Printable Version Blood and Diversity People come in all different shapes, sizes and ... groups. Therefore it is essential that the donor diversity match the patient diversity. For example, U-negative ...

  11. Significant steps in the evolution of analytical chemistry--is the today's analytical chemistry only chemistry?

    PubMed

    Karayannis, Miltiades I; Efstathiou, Constantinos E

    2012-12-15

    In this review the history of chemistry and specifically the history and the significant steps of the evolution of analytical chemistry are presented. In chronological time spans, covering the ancient world, the middle ages, the period of the 19th century, and the three evolutional periods, from the verge of the 19th century to contemporary times, it is given information for the progress of chemistry and analytical chemistry. During this period, analytical chemistry moved gradually from its pure empirical nature to more rational scientific activities, transforming itself to an autonomous branch of chemistry and a separate discipline. It is also shown that analytical chemistry moved gradually from the status of exclusive serving the chemical science, towards serving, the environment, health, law, almost all areas of science and technology, and the overall society. Some recommendations are also directed to analytical chemistry educators concerning the indispensable nature of knowledge of classical analytical chemistry and the associated laboratory exercises and to analysts, in general, why it is important to use the chemical knowledge to make measurements on problems of everyday life.

  12. Analytic study of the chain dark decomposition reaction of iodides - atomic iodine donors - in the active medium of a pulsed chemical oxygen-iodine laser: 2. Limiting parameters of the branching chain dark decomposition reaction of iodides

    SciTech Connect

    Andreeva, Tamara L; Kuznetsova, S V; Maslov, Aleksandr I; Sorokin, Vadim N

    2009-08-31

    The final stages in the development of a branching chain decomposition reaction of iodide in the active medium of a pulsed chemical oxygen-iodine laser (COIL) are analysed. Approximate expressions are derived to calculate the limiting parameters of the chain reaction: the final degree of iodide decomposition, the maximum concentration of excited iodine atoms, the time of its achievement, and concentrations of singlet oxygen and iodide at that moment. The limiting parameters, calculated by using these expressions for a typical composition of the active medium of a pulsed COIL, well coincide with the results of numerical calculations. (active media)

  13. Competing on talent analytics.

    PubMed

    Davenport, Thomas H; Harris, Jeanne; Shapiro, Jeremy

    2010-10-01

    Do investments in your employees actually affect workforce performance? Who are your top performers? How can you empower and motivate other employees to excel? Leading-edge companies such as Google, Best Buy, Procter & Gamble, and Sysco use sophisticated data-collection technology and analysis to answer these questions, leveraging a range of analytics to improve the way they attract and retain talent, connect their employee data to business performance, differentiate themselves from competitors, and more. The authors present the six key ways in which companies track, analyze, and use data about their people-ranging from a simple baseline of metrics to monitor the organization's overall health to custom modeling for predicting future head count depending on various "what if" scenarios. They go on to show that companies competing on talent analytics manage data and technology at an enterprise level, support what analytical leaders do, choose realistic targets for analysis, and hire analysts with strong interpersonal skills as well as broad expertise.

  14. Monitoring the analytic surface.

    PubMed

    Spence, D P; Mayes, L C; Dahl, H

    1994-01-01

    How do we listen during an analytic hour? Systematic analysis of the speech patterns of one patient (Mrs. C.) strongly suggests that the clustering of shared pronouns (e.g., you/me) represents an important aspect of the analytic surface, preconsciously sensed by the analyst and used by him to determine when to intervene. Sensitivity to these patterns increases over the course of treatment, and in a final block of 10 hours shows a striking degree of contingent responsivity: specific utterances by the patient are consistently echoed by the analyst's interventions.

  15. Correlated Raman micro-spectroscopy and scanning electron microscopy analyses of flame retardants in environmental samples: a micro-analytical tool for probing chemical composition, origin and spatial distribution.

    PubMed

    Ghosal, Sutapa; Wagner, Jeff

    2013-07-07

    We present correlated application of two micro-analytical techniques: scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and Raman micro-spectroscopy (RMS) for the non-invasive characterization and molecular identification of flame retardants (FRs) in environmental dusts and consumer products. The SEM/EDS-RMS technique offers correlated, morphological, molecular, spatial distribution and semi-quantitative elemental concentration information at the individual particle level with micrometer spatial resolution and minimal sample preparation. The presented methodology uses SEM/EDS analyses for rapid detection of particles containing FR specific elements as potential indicators of FR presence in a sample followed by correlated RMS analyses of the same particles for characterization of the FR sub-regions and surrounding matrices. The spatially resolved characterization enabled by this approach provides insights into the distributional heterogeneity as well as potential transfer and exposure mechanisms for FRs in the environment that is typically not available through traditional FR analysis. We have used this methodology to reveal a heterogeneous distribution of highly concentrated deca-BDE particles in environmental dust, sometimes in association with identifiable consumer materials. The observed coexistence of deca-BDE with consumer material in dust is strongly indicative of its release into the environment via weathering/abrasion of consumer products. Ingestion of such enriched FR particles in dust represents a potential for instantaneous exposure to high FR concentrations. Therefore, correlated SEM/RMS analysis offers a novel investigative tool for addressing an area of important environmental concern.

  16. Health informatics and analytics - building a program to integrate business analytics across clinical and administrative disciplines.

    PubMed

    Tremblay, Monica Chiarini; Deckard, Gloria J; Klein, Richard

    2016-07-01

    Health care organizations must develop integrated health information systems to respond to the numerous government mandates driving the movement toward reimbursement models emphasizing value-based and accountable care. Success in this transition requires integrated data analytics, supported by the combination of health informatics, interoperability, business process design, and advanced decision support tools. This case study presents the development of a master's level cross- and multidisciplinary informatics program offered through a business school. The program provides students from diverse backgrounds with the knowledge, leadership, and practical application skills of health informatics, information systems, and data analytics that bridge the interests of clinical and nonclinical professionals. This case presents the actions taken and challenges encountered in navigating intra-university politics, specifying curriculum, recruiting the requisite interdisciplinary faculty, innovating the educational format, managing students with diverse educational and professional backgrounds, and balancing multiple accreditation agencies.

  17. VALIDATION OF STANDARD ANALYTICAL PROTOCOL FOR ...

    EPA Pesticide Factsheets

    There is a growing concern with the potential for terrorist use of chemical weapons to cause civilian harm. In the event of an actual or suspected outdoor release of chemically hazardous material in a large area, the extent of contamination must be determined. This requires a system with the ability to prepare and quickly analyze a large number of contaminated samples for the traditional chemical agents, as well as numerous toxic industrial chemicals. Liquid samples (both aqueous and organic), solid samples (e.g., soil), vapor samples (e.g., air) and mixed state samples, all ranging from household items to deceased animals, may require some level of analyses. To meet this challenge, the U.S. Environmental Protection Agency (U.S. EPA) National Homeland Security Research Center, in collaboration with experts from across U.S. EPA and other Federal Agencies, initiated an effort to identify analytical methods for the chemical and biological agents that could be used to respond to a terrorist attack or a homeland security incident. U.S. EPA began development of standard analytical protocols (SAPs) for laboratory identification and measurement of target agents in case of a contamination threat. These methods will be used to help assist in the identification of existing contamination, the effectiveness of decontamination, as well as clearance for the affected population to reoccupy previously contaminated areas. One of the first SAPs developed was for the determin

  18. Analytics: Changing the Conversation

    ERIC Educational Resources Information Center

    Oblinger, Diana G.

    2013-01-01

    In this third and concluding discussion on analytics, the author notes that we live in an information culture. We are accustomed to having information instantly available and accessible, along with feedback and recommendations. We want to know what people think and like (or dislike). We want to know how we compare with "others like me."…

  19. Social Learning Analytics

    ERIC Educational Resources Information Center

    Buckingham Shum, Simon; Ferguson, Rebecca

    2012-01-01

    We propose that the design and implementation of effective "Social Learning Analytics (SLA)" present significant challenges and opportunities for both research and enterprise, in three important respects. The first is that the learning landscape is extraordinarily turbulent at present, in no small part due to technological drivers.…

  20. Analytical tools for groundwater pollution assessment

    SciTech Connect

    Hantush, M.M.; Islam, M.R.; Marino, M.A.

    1998-06-01

    This paper deals with the development of analytical screening-exposure models (indices) and their potential application to regulate the use of hazardous chemicals and the design of ground water buffer strips. The indices describe the leaching of solutes below the root zone (mass fraction), emissions to the water table, and mass fraction of the contaminant intercepted by a well or a surface water body.

  1. Diverse Classrooms, Diverse Curriculum, Diverse Complications: Three Teacher Perspectives

    ERIC Educational Resources Information Center

    Ungemah, Lori D.

    2015-01-01

    Racial, ethnic, linguistic, and religious diversity continues to increase in classrooms. Many call for a more diverse curriculum, but curricular diversity brings its own challenges to both teachers and students. These three vignettes are drawn from my ethnographic data at Atlantic High School in Brooklyn, New York, where I worked for ten years as…

  2. Non-planar chemical preconcentrator

    DOEpatents

    Manginell, Ronald P.; Adkins, Douglas R.; Sokolowski, Sara S.; Lewis, Patrick R.

    2006-10-10

    A non-planar chemical preconcentrator comprises a high-surface area, low mass, three-dimensional, flow-through sorption support structure that can be coated or packed with a sorptive material. The sorptive material can collect and concentrate a chemical analyte from a fluid stream and rapidly release it as a very narrow temporal plug for improved separations in a microanalytical system. The non-planar chemical preconcentrator retains most of the thermal and fabrication benefits of a planar preconcentrator, but has improved ruggedness and uptake, while reducing sorptive coating concerns and extending the range of collectible analytes.

  3. Tortuous path chemical preconcentrator

    DOEpatents

    Manginell, Ronald P.; Lewis, Patrick R.; Adkins, Douglas R.; Wheeler, David R.; Simonson, Robert J.

    2010-09-21

    A non-planar, tortuous path chemical preconcentrator has a high internal surface area having a heatable sorptive coating that can be used to selectively collect and concentrate one or more chemical species of interest from a fluid stream that can be rapidly released as a concentrated plug into an analytical or microanalytical chain for separation and detection. The non-planar chemical preconcentrator comprises a sorptive support structure having a tortuous flow path. The tortuosity provides repeated twists, turns, and bends to the flow, thereby increasing the interfacial contact between sample fluid stream and the sorptive material. The tortuous path also provides more opportunities for desorption and readsorption of volatile species. Further, the thermal efficiency of the tortuous path chemical preconcentrator is comparable or superior to the prior non-planar chemical preconcentrator. Finally, the tortuosity can be varied in different directions to optimize flow rates during the adsorption and desorption phases of operation of the preconcentrator.

  4. Contemporary sample stacking in analytical electrophoresis.

    PubMed

    Šlampová, Andrea; Malá, Zdena; Pantůčková, Pavla; Gebauer, Petr; Boček, Petr

    2013-01-01

    Sample stacking is a term denoting a multifarious class of methods and their names that are used daily in CE for online concentration of diluted samples to enhance separation efficiency and sensitivity of analyses. The essence of these methods is that analytes present at low concentrations in a large injected sample zone are concentrated into a short and sharp zone (stack) in the separation capillary. Then the stacked analytes are separated and detected. Regardless of the diversity of the stacking electromigration methods, one can distinguish four main principles that form the bases of nearly all of them: (i) Kohlrausch adjustment of concentrations, (ii) pH step, (iii) micellar methods, and (iv) transient ITP. This contribution is a continuation of our previous reviews on the topic and brings an overview of papers published during 2010-2012 and relevant to the mentioned principles (except the last one which is covered by another review in this issue).

  5. Chemical Emergencies

    MedlinePlus

    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 ...

  6. Parallel extraction columns and parallel analytical columns coupled with liquid chromatography/tandem mass spectrometry for on-line simultaneous quantification of a drug candidate and its six metabolites in dog plasma.

    PubMed

    Xia, Y Q; Hop, C E; Liu, D Q; Vincent, S H; Chiu, S H

    2001-01-01

    A method with parallel extraction columns and parallel analytical columns (PEC-PAC) for on-line high-flow liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed and validated for simultaneous quantification of a drug candidate and its six metabolites in dog plasma. Two on-line extraction columns were used in parallel for sample extraction and two analytical columns were used in parallel for separation and analysis. The plasma samples, after addition of an internal standard solution, were directly injected onto the PEC-PAC system for purification and analysis. This method allowed the use of one of the extraction columns for analyte purification while the other was being equilibrated. Similarly, one of the analytical columns was employed to separate the analytes while the other was undergoing equilibration. Therefore, the time needed for re-conditioning both extraction and analytical columns was not added to the total analysis time, which resulted in a shorter run time and higher throughput. Moreover, the on-line column extraction LC/MS/MS method made it possible to extract and analyze all seven analytes simultaneously with good precision and accuracy despite their chemical class diversity that included primary, secondary and tertiary amines, an alcohol, an aldehyde and a carboxylic acid. The method was validated with the standard curve ranging from 5.00 to 5000 ng/mL. The intra- and inter-day precision was no more than 8% CV and the assay accuracy was between 95 and 107%.

  7. The Chief Diversity Officer

    ERIC Educational Resources Information Center

    Williams, Damon; Wade-Golden, Katrina

    2007-01-01

    Numerous institutions are moving toward the chief diversity officer model of leading and managing diversity in higher education. These officers carry formal administrative titles and ranks that range from vice president for institutional diversity to associate vice chancellor for diversity and climate and dean of diversity and academic engagement.…

  8. Requirements for Predictive Analytics

    SciTech Connect

    Troy Hiltbrand

    2012-03-01

    It is important to have a clear understanding of how traditional Business Intelligence (BI) and analytics are different and how they fit together in optimizing organizational decision making. With tradition BI, activities are focused primarily on providing context to enhance a known set of information through aggregation, data cleansing and delivery mechanisms. As these organizations mature their BI ecosystems, they achieve a clearer picture of the key performance indicators signaling the relative health of their operations. Organizations that embark on activities surrounding predictive analytics and data mining go beyond simply presenting the data in a manner that will allow decisions makers to have a complete context around the information. These organizations generate models based on known information and then apply other organizational data against these models to reveal unknown information.

  9. Multifunctional nanoparticles: analytical prospects.

    PubMed

    de Dios, Alejandro Simón; Díaz-García, Marta Elena

    2010-05-07

    Multifunctional nanoparticles are among the most exciting nanomaterials with promising applications in analytical chemistry. These applications include (bio)sensing, (bio)assays, catalysis and separations. Although most of these applications are based on the magnetic, optical and electrochemical properties of multifunctional nanoparticles, other aspects such as the synergistic effect of the functional groups and the amplification effect associated with the nanoscale dimension have also been observed. Considering not only the nature of the raw material but also the shape, there is a huge variety of nanoparticles. In this review only magnetic, quantum dots, gold nanoparticles, carbon and inorganic nanotubes as well as silica, titania and gadolinium oxide nanoparticles are addressed. This review presents a narrative summary on the use of multifunctional nanoparticles for analytical applications, along with a discussion on some critical challenges existing in the field and possible solutions that have been or are being developed to overcome these challenges.

  10. Avatars in Analytical Gaming

    SciTech Connect

    Cowell, Andrew J.; Cowell, Amanda K.

    2009-08-29

    This paper discusses the design and use of anthropomorphic computer characters as nonplayer characters (NPC’s) within analytical games. These new environments allow avatars to play a central role in supporting training and education goals instead of planning the supporting cast role. This new ‘science’ of gaming, driven by high-powered but inexpensive computers, dedicated graphics processors and realistic game engines, enables game developers to create learning and training opportunities on par with expensive real-world training scenarios. However, there needs to be care and attention placed on how avatars are represented and thus perceived. A taxonomy of non-verbal behavior is presented and its application to analytical gaming discussed.

  11. Ultrasound in analytical chemistry.

    PubMed

    Priego Capote, F; Luque de Castro, M D

    2007-01-01

    Ultrasound is a type of energy which can help analytical chemists in almost all their laboratory tasks, from cleaning to detection. A generic view of the different steps which can be assisted by ultrasound is given here. These steps include preliminary operations usually not considered in most analytical methods (e.g. cleaning, degassing, and atomization), sample preparation being the main area of application. In sample preparation ultrasound is used to assist solid-sample treatment (e.g. digestion, leaching, slurry formation) and liquid-sample preparation (e.g. liquid-liquid extraction, emulsification, homogenization) or to promote heterogeneous sample treatment (e.g. filtration, aggregation, dissolution of solids, crystallization, precipitation, defoaming, degassing). Detection techniques based on use of ultrasonic radiation, the principles on which they are based, responses, and the quantities measured are also discussed.

  12. 21 CFR 1309.73 - Employee responsibility to report diversion.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Employee responsibility to report diversion. 1309... § 1309.73 Employee responsibility to report diversion. Reports of listed chemical diversion by fellow... all reasonable steps to protect the confidentiality of the information and the identity of...

  13. 21 CFR 1309.73 - Employee responsibility to report diversion.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Employee responsibility to report diversion. 1309... § 1309.73 Employee responsibility to report diversion. Reports of listed chemical diversion by fellow... all reasonable steps to protect the confidentiality of the information and the identity of...

  14. Analytic Modeling of Insurgencies

    DTIC Science & Technology

    2014-08-01

    influenced by interests and utilities. 4.1 Carrots and Sticks An analytic model that captures the aforementioned utilitarian aspect is presented in... carrots ” x. A dynamic utility-based model is developed in [26] in which the state variables are the fractions of contrarians (supporters of the...Unanticipated Political Revolution," Public Choice, vol. 61, pp. 41-74, 1989. [26] M. P. Atkinson, M. Kress and R. Szechtman, " Carrots , Sticks and Fog

  15. Industrial Analytics Corporation

    SciTech Connect

    Industrial Analytics Corporation

    2004-01-30

    The lost foam casting process is sensitive to the properties of the EPS patterns used for the casting operation. In this project Industrial Analytics Corporation (IAC) has developed a new low voltage x-ray instrument for x-ray radiography of very low mass EPS patterns. IAC has also developed a transmitted visible light method for characterizing the properties of EPS patterns. The systems developed are also applicable to other low density materials including graphite foams.

  16. Competing on analytics.

    PubMed

    Davenport, Thomas H

    2006-01-01

    We all know the power of the killer app. It's not just a support tool; it's a strategic weapon. Companies questing for killer apps generally focus all their firepower on the one area that promises to create the greatest competitive advantage. But a new breed of organization has upped the stakes: Amazon, Harrah's, Capital One, and the Boston Red Sox have all dominated their fields by deploying industrial-strength analytics across a wide variety of activities. At a time when firms in many industries offer similar products and use comparable technologies, business processes are among the few remaining points of differentiation--and analytics competitors wring every last drop of value from those processes. Employees hired for their expertise with numbers or trained to recognize their importance are armed with the best evidence and the best quantitative tools. As a result, they make the best decisions. In companies that compete on analytics, senior executives make it clear--from the top down--that analytics is central to strategy. Such organizations launch multiple initiatives involving complex data and statistical analysis, and quantitative activity is managed atthe enterprise (not departmental) level. In this article, professor Thomas H. Davenport lays out the characteristics and practices of these statistical masters and describes some of the very substantial changes other companies must undergo in order to compete on quantitative turf. As one would expect, the transformation requires a significant investment in technology, the accumulation of massive stores of data, and the formulation of company-wide strategies for managing the data. But, at least as important, it also requires executives' vocal, unswerving commitment and willingness to change the way employees think, work, and are treated.

  17. Novel analytical approach for brominated flame retardants based on the use of gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry with emphasis in highly brominated congeners.

    PubMed

    Portolés, Tania; Sales, Carlos; Gómara, Belén; Sancho, Juan Vicente; Beltrán, Joaquim; Herrero, Laura; González, María José; Hernández, Félix

    2015-10-06

    The analysis of brominated flame retardants (BFRs) commonly relies on the use of gas chromatography coupled to mass spectrometry (GC-MS) operating in electron ionization (EI) and electron capture negative ionization (ECNI) modes using quadrupole, triple quadrupole, ion trap, and magnetic sector analyzers. However, these brominated contaminants are examples of compounds for which a soft and robust ionization technique might be favorable since they show high fragmentation in EI and low specificity in ECNI. In addition, the low limits of quantification (0.01 ng/g) required by European Commission Recommendation 2014/118/EU on the monitoring of traces of BFRs in food put stress on the use of highly sensitive techniques/methods. In this work, a new approach for the extremely sensitive determination of BFRs taking profit of the potential of atmospheric pressure chemical ionization (APCI) combined with GC and triple quadrupole (QqQ) mass analyzer is proposed. The objective was to explore the potential of this approach for the BFRs determination in samples at pg/g levels, taking marine samples and a cream sample as a model. Ionization and fragmentation behavior of 14 PBDEs (congeners 28, 47, 66, 85, 99, 100, 153, 154, 183, 184, 191, 196, 197, and 209) and two novel BFRs, decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), in the GC-APCI-MS system has been investigated. The formation of highly abundant (quasi) molecular ion was the main advantage observed in relation to EI. Thus, a notable improvement in sensitivity and specificity was observed when using it as precursor ion in tandem MS. The improved detectability (LODs < 10 fg) achieved when using APCI compared to EI has been demonstrated, which is especially relevant for highly brominated congeners. Analysis of samples from an intercomparison exercise and samples from the marine field showed the potential of this approach for the reliable identification and quantification at very low

  18. Fabricating Cotton Analytical Devices.

    PubMed

    Lin, Shang-Chi; Hsu, Min-Yen; Kuan, Chen-Meng; Tseng, Fan-Gang; Cheng, Chao-Min

    2016-08-30

    A robust, low-cost analytical device should be user-friendly, rapid, and affordable. Such devices should also be able to operate with scarce samples and provide information for follow-up treatment. Here, we demonstrate the development of a cotton-based urinalysis (i.e., nitrite, total protein, and urobilinogen assays) analytical device that employs a lateral flow-based format, and is inexpensive, easily fabricated, rapid, and can be used to conduct multiple tests without cross-contamination worries. Cotton is composed of cellulose fibers with natural absorptive properties that can be leveraged for flow-based analysis. The simple but elegant fabrication process of our cotton-based analytical device is described in this study. The arrangement of the cotton structure and test pad takes advantage of the hydrophobicity and absorptive strength of each material. Because of these physical characteristics, colorimetric results can persistently adhere to the test pad. This device enables physicians to receive clinical information in a timely manner and shows great potential as a tool for early intervention.

  19. Big Data Analytics for Genomic Medicine.

    PubMed

    He, Karen Y; Ge, Dongliang; He, Max M

    2017-02-15

    Genomic medicine attempts to build individualized strategies for diagnostic or therapeutic decision-making by utilizing patients' genomic information. Big Data analytics uncovers hidden patterns, unknown correlations, and other insights through examining large-scale various data sets. While integration and manipulation of diverse genomic data and comprehensive electronic health records (EHRs) on a Big Data infrastructure exhibit challenges, they also provide a feasible opportunity to develop an efficient and effective approach to identify clinically actionable genetic variants for individualized diagnosis and therapy. In this paper, we review the challenges of manipulating large-scale next-generation sequencing (NGS) data and diverse clinical data derived from the EHRs for genomic medicine. We introduce possible solutions for different challenges in manipulating, managing, and analyzing genomic and clinical data to implement genomic medicine. Additionally, we also present a practical Big Data toolset for identifying clinically actionable genetic variants using high-throughput NGS data and EHRs.

  20. Big Data Analytics for Genomic Medicine

    PubMed Central

    He, Karen Y.; Ge, Dongliang; He, Max M.

    2017-01-01

    Genomic medicine attempts to build individualized strategies for diagnostic or therapeutic decision-making by utilizing patients’ genomic information. Big Data analytics uncovers hidden patterns, unknown correlations, and other insights through examining large-scale various data sets. While integration and manipulation of diverse genomic data and comprehensive electronic health records (EHRs) on a Big Data infrastructure exhibit challenges, they also provide a feasible opportunity to develop an efficient and effective approach to identify clinically actionable genetic variants for individualized diagnosis and therapy. In this paper, we review the challenges of manipulating large-scale next-generation sequencing (NGS) data and diverse clinical data derived from the EHRs for genomic medicine. We introduce possible solutions for different challenges in manipulating, managing, and analyzing genomic and clinical data to implement genomic medicine. Additionally, we also present a practical Big Data toolset for identifying clinically actionable genetic variants using high-throughput NGS data and EHRs. PMID:28212287

  1. Chemically-functionalized microcantilevers for detection of chemical, biological and explosive material

    SciTech Connect

    Pinnaduwage, Lal A; Thundat, Thomas G; Brown, Gilbert M; Hawk, John Eric; Boiadjiev, Vassil I

    2007-04-24

    A chemically functionalized cantilever system has a cantilever coated on one side thereof with a reagent or biological species which binds to an analyte. The system is of particular value when the analyte is a toxic chemical biological warfare agent or an explosive.

  2. Diversity Education and Identity Development in an Information Technology Course

    ERIC Educational Resources Information Center

    Trauth, Eileen M.; Johnson, R. Neill; Morgan, Allison; Huang, Haiyan; Quesenberry, Jeria

    2007-01-01

    A particular educational challenge for universities that are not located in major metropolitan areas rich in demographic diversity is how to prepare those in the future labor force to value diversity and understand the ways in which their behaviors can contribute to or detract from a welcoming climate. Building on an analytical framework developed…

  3. Diversity oriented synthesis: a challenge for synthetic chemists.

    PubMed

    Bender, A; Fergus, S; Galloway, W R J D; Glansdorp, F G; Marsden, D M; Nicholson, R L; Spandl, R J; Thomas, G L; Wyatt, E E; Glen, R C; Spring, D R

    2006-01-01

    This article covers the diversity-oriented synthesis (DOS) of small molecules in order to generate a collection of pure compounds that are attractive for lead generation in a phenotypic, high-throughput screening approach useful for chemical genetics and drug discovery programmes. Nature synthesizes a rich structural diversity of small molecules, however, unfortunately, there are some disadvantages with using natural product sources for diverse small-molecule discovery. Nevertheless we have a lot to learn from nature. The efficient chemical synthesis of structural diversity (and complexity) is the aim of DOS. Highlights of this article include a discussion of nature's and synthetic chemists' strategies to obtain structural diversity and an analysis of molecular descriptors used to classify compounds. The assessment of how successful one diversity-oriented synthesis is vs another is subjective; therefore we use freely available software (www.cheminformatics.org/diversity) to assess structural diversity in any combinatorial synthesis.

  4. Analytical Chemistry Core Capability Assessment - Preliminary Report

    SciTech Connect

    Barr, Mary E.; Farish, Thomas J.

    2012-05-16

    The concept of 'core capability' can be nebulous one. Even at a fairly specific level, where core capability equals maintaining essential services, it is highly dependent upon the perspective of the requestor. Samples are submitted to analytical services because the requesters do not have the capability to conduct adequate analyses themselves. Some requests are for general chemical information in support of R and D, process control, or process improvement. Many analyses, however, are part of a product certification package and must comply with higher-level customer quality assurance requirements. So which services are essential to that customer - just those for product certification? Does the customer also (indirectly) need services that support process control and improvement? And what is the timeframe? Capability is often expressed in terms of the currently utilized procedures, and most programmatic customers can only plan a few years out, at best. But should core capability consider the long term where new technologies, aging facilities, and personnel replacements must be considered? These questions, and a multitude of others, explain why attempts to gain long-term consensus on the definition of core capability have consistently failed. This preliminary report will not try to define core capability for any specific program or set of programs. Instead, it will try to address the underlying concerns that drive the desire to determine core capability. Essentially, programmatic customers want to be able to call upon analytical chemistry services to provide all the assays they need, and they don't want to pay for analytical chemistry services they don't currently use (or use infrequently). This report will focus on explaining how the current analytical capabilities and methods evolved to serve a variety of needs with a focus on why some analytes have multiple analytical techniques, and what determines the infrastructure for these analyses. This information will be

  5. MERRA Analytic Services

    NASA Astrophysics Data System (ADS)

    Schnase, J. L.; Duffy, D. Q.; McInerney, M. A.; Tamkin, G. S.; Thompson, J. H.; Gill, R.; Grieg, C. M.

    2012-12-01

    MERRA Analytic Services (MERRA/AS) is a cyberinfrastructure resource for developing and evaluating a new generation of climate data analysis capabilities. MERRA/AS supports OBS4MIP activities by reducing the time spent in the preparation of Modern Era Retrospective-Analysis for Research and Applications (MERRA) data used in data-model intercomparison. It also provides a testbed for experimental development of high-performance analytics. MERRA/AS is a cloud-based service built around the Virtual Climate Data Server (vCDS) technology that is currently used by the NASA Center for Climate Simulation (NCCS) to deliver Intergovernmental Panel on Climate Change (IPCC) data to the Earth System Grid Federation (ESGF). Crucial to its effectiveness, MERRA/AS's servers will use a workflow-generated realizable object capability to perform analyses over the MERRA data using the MapReduce approach to parallel storage-based computation. The results produced by these operations will be stored by the vCDS, which will also be able to host code sets for those who wish to explore the use of MapReduce for more advanced analytics. While the work described here will focus on the MERRA collection, these technologies can be used to publish other reanalysis, observational, and ancillary OBS4MIP data to ESGF and, importantly, offer an architectural approach to climate data services that can be generalized to applications and customers beyond the traditional climate research community. In this presentation, we describe our approach, experiences, lessons learned,and plans for the future.; (A) MERRA/AS software stack. (B) Example MERRA/AS interfaces.

  6. Quality Indicators for Learning Analytics

    ERIC Educational Resources Information Center

    Scheffel, Maren; Drachsler, Hendrik; Stoyanov, Slavi; Specht, Marcus

    2014-01-01

    This article proposes a framework of quality indicators for learning analytics that aims to standardise the evaluation of learning analytics tools and to provide a mean to capture evidence for the impact of learning analytics on educational practices in a standardised manner. The criteria of the framework and its quality indicators are based on…

  7. Learning Analytics: Readiness and Rewards

    ERIC Educational Resources Information Center

    Friesen, Norm

    2013-01-01

    This position paper introduces the relatively new field of learning analytics, first by considering the relevant meanings of both "learning" and "analytics," and then by looking at two main levels at which learning analytics can be or has been implemented in educational organizations. Although integrated turnkey systems or…

  8. ANALYTICAL CHEMISTRY RESEARCH NEEDS FOR ...

    EPA Pesticide Factsheets

    The consensus among environmental scientists and risk assessors is that the fate and effects of pharmaceutical and personal care products (PPCPS) in the environment are poorly understood. Many classes of PPCPs have yet to be investigated. Acquisition of trends data for a suite of PPCPs (representatives from each of numerous significant classes), shown to recur amongst municipal wastewater treatment plants across the country, may prove of key importance. The focus of this paper is an overview of some of the analytical methods being developed at the Environmenental Protection Agency and their application to wastewater and surface water samples. Because PPCPs are generally micro-pollutants, emphasis is on development of enrichment and pre- concentration techniques using various means of solid-phase extraction. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality. Located In the subtasks are the various research projects being performed in support of this Task and more in-depth coverage of each project. Briefly, each project's objective is stated below.Subtask 1: To integrate state-of-the-art technologies (polar organic chemical integrative samplers, advanced solid-phase extraction methodologies with liquid chromatography/electrospray/mass spectrometry) and apply them to studying the sources and fate of a select list of PPCP

  9. The analytic renormalization group

    NASA Astrophysics Data System (ADS)

    Ferrari, Frank

    2016-08-01

    Finite temperature Euclidean two-point functions in quantum mechanics or quantum field theory are characterized by a discrete set of Fourier coefficients Gk, k ∈ Z, associated with the Matsubara frequencies νk = 2 πk / β. We show that analyticity implies that the coefficients Gk must satisfy an infinite number of model-independent linear equations that we write down explicitly. In particular, we construct "Analytic Renormalization Group" linear maps Aμ which, for any choice of cut-off μ, allow to express the low energy Fourier coefficients for |νk | < μ (with the possible exception of the zero mode G0), together with the real-time correlators and spectral functions, in terms of the high energy Fourier coefficients for |νk | ≥ μ. Operating a simple numerical algorithm, we show that the exact universal linear constraints on Gk can be used to systematically improve any random approximate data set obtained, for example, from Monte-Carlo simulations. Our results are illustrated on several explicit examples.

  10. A review of opportunities for electrospun nanofibers in analytical chemistry.

    PubMed

    Chigome, Samuel; Torto, Nelson

    2011-11-07

    Challenges associated with analyte and matrix complexities and the ever increasing pressure from all sectors of industry for alternative analytical devices, have necessitated the development and application of new materials in analytical chemistry. To date, nanomaterials have emerged as having excellent properties for analytical chemistry applications mainly due to their large surface area to volume ratio and the availability of a wide variety of chemical and morphological modification methods. Of the available nanofibrous material fabrication methods, electrospinning has emerged as the most versatile. It is the aim of this contribution to highlight some of the recent developments that harness the great potential shown by electrospun nanofibers for application in analytical chemistry. The review discusses the use of electrospun nanofibers as a platform for low resolution separation or as a chromatographic sorbent bed for high resolution separation. It concludes by discussing the applications of electrospun nanofibers in detection systems with a specific focus on the development of simple electrospun nanofiber based colorimetric probes.

  11. Chemically diverse polymer microarrays and high throughput surface characterisation: a method for discovery of materials for stem cell culture† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c4bm00054d Click here for additional data file.

    PubMed Central

    Celiz, A. D.; Smith, J. G. W.; Patel, A. K.; Langer, R.; Anderson, D. G.; Barrett, D. A.; Young, L. E.; Davies, M. C.; Denning, C.

    2014-01-01

    Materials discovery provides the opportunity to identify novel materials that are tailored to complex biological environments by using combinatorial mixing of monomers to form large libraries of polymers as micro arrays. The materials discovery approach is predicated on the use of the largest chemical diversity possible, yet previous studies into human pluripotent stem cell (hPSC) response to polymer microarrays have been limited to 20 or so different monomer identities in each study. Here we show that it is possible to print and assess cell adhesion of 141 different monomers in a microarray format. This provides access to the largest chemical space to date, allowing us to meet the regenerative medicine challenge to provide scalable synthetic culture ware. This study identifies new materials suitable for hPSC expansion that could not have been predicted from previous knowledge of cell-material interactions. PMID:25328672

  12. 10 Diversity Champions II

    ERIC Educational Resources Information Center

    Nealy, Michelle J.; Pluviose, David; Roach, Ronald

    2008-01-01

    Introducing the "Champions of Diversity" in the Academic Kickoff issue proved a timely reminder of the mission of Diverse during the lead up to the 25th anniversary of Cox, Matthews and Associates, the founder of the former Black Issues in Higher Education and publisher of Diverse. In this edition, the editors at Diverse unveil its second slate of…

  13. Concepts of Diversity.

    ERIC Educational Resources Information Center

    Jacklin, Phil

    This paper attempts to establish a theory of communication essential to democratic diversity. Twelve kinds of diversity, divided into two classes, are described. One class relates to the way in which diverse things differ, the other class relates to the kinds of things which are diverse. The criteria for evaluating the importance of a certain kind…

  14. The environmental challenge for analytical sciences.

    PubMed

    Grasserbauer, Manfred

    2010-05-01

    In this paper the major elements of the European Union's policy on environmental protection and sustainable development and the resulting challenges for analytical sciences are presented. The priority issues dealt with are: Sustainable management of natural resources: air, water and soil Climate change and clean energy Global development cooperation Analytical sciences are required to provide policy-relevant information for the development and implementation of European Union legislation and form a strong pillar for a sustainable evolution of our region and our planet. It shows what information needs to be provided, how the necessary quality levels can be achieved and what new approaches, e.g. combining measurements and modelling, or earth observations with in situ chemical/physical measurements, need to be taken to achieve an integrated assessment of the state of the environment and to develop approaches for sustainable development.

  15. Reduction of INTEC Analytical Radioactive Liquid Waste

    SciTech Connect

    Johnson, Virgil James; Hu, Jian Sheng; Chambers, Andrea

    1999-06-01

    This report details the evaluation of the reduction in radioactive liquid waste from the analytical laboratories sent to the Process Effluent Waste system (deep tanks). The contributors are the Analytical Laboratories Department (ALD), the Waste Operations Department, the laboratories at CPP-637, and natural run off. Other labs were contacted to learn of methods used and if any new technologies had emerged. A waste generation database was made from the current methods in use in the ALD. From this database, methods were targeted to reduce waste. Individuals were contacted on ways to reduce waste. The results are: a new method generating much less waste, several methods being handled differently, some cleaning processes being changed to reduce waste, and changes to reduce chemicals to waste.

  16. Reduction of INTEC Analytical Radioactive Liquid Wastes

    SciTech Connect

    V. J. Johnson; J. S. Hu; A. G. Chambers

    1999-06-01

    This report details the evaluation of the reduction in radioactive liquid waste from the analytical laboratories sent to the Process Effluent Waste system (deep tanks). The contributors are the Analytical Laboratories Department (ALD), the Waste Operations Department, the laboratories at CPP-637, and natural run off. Other labs were contacted to learn the methods used and if any new technologies had emerged. A waste generation database was made from the current methods in used in the ALD. From this database, methods were targeted to reduce waste. Individuals were contacted on ways to reduce waste. The results are: a new method generating much less waste, several methods being handled differently, some cleaning processes being changed to reduce waste, and changes to reduce chemicals to waste.

  17. Directory of Analytical Methods, Department 1820

    SciTech Connect

    Whan, R.E.

    1986-01-01

    The Materials Characterization Department performs chemical, physical, and thermophysical analyses in support of programs throughout the Laboratories. The department has a wide variety of techniques and instruments staffed by experienced personnel available for these analyses, and we strive to maintain near state-of-the-art technology by continued updates. We have prepared this Directory of Analytical Methods in order to acquaint you with our capabilities and to help you identify personnel who can assist with your analytical needs. The descriptions of the various capabilities are requester-oriented and have been limited in length and detail. Emphasis has been placed on applications and limitations with notations of estimated analysis time and alternative or related techniques. A short, simplified discussion of underlying principles is also presented along with references if more detail is desired. The contents of this document have been organized in the order: bulky analysis, microanalysis, surface analysis, optical and thermal property measurements.

  18. Chemical Peel

    MedlinePlus

    ... be done at different depths — light, medium or deep — depending on your desired results. Each type of ... chemical peel after 12 months to maintain results. Deep chemical peel. A deep chemical peel removes skin ...

  19. Characterization of Analytical Reference Glass-1 (ARG-1)

    SciTech Connect

    Smith, G.L.

    1993-12-01

    High-level radioactive waste may be immobilized in borosilicate glass at the West Valley Demonstration Project, West Valley, New York, the Defense Waste Processing Facility (DWPF), Aiken, South Carolina, and the Hanford Waste Vitrification Project (HWVP), Richland, Washington. The vitrified waste form will be stored in stainless steel canisters before its eventual transfer to a geologic repository for long-term disposal. Waste Acceptance Product Specifications (WAPS) (DOE 1993), Section 1.1.2 requires that the waste form producers must report the measured chemical composition of the vitrified waste in their production records before disposal. Chemical analysis of glass waste forms is receiving increased attention due to qualification requirements of vitrified waste forms. The Pacific Northwest Laboratory (PNL) has been supporting the glass producers` analytical laboratories by a continuing program of multilaboratory analytical testing using interlaboratory ``round robin`` methods. At the PNL Materials Characterization Center Analytical Round Robin 4 workshop ``Analysis of Nuclear Waste Glass and Related Materials,`` January 16--17, 1990, Pleasanton, California, the meeting attendees decided that simulated nuclear waste analytical reference glasses were needed for use as analytical standards. Use of common standard analytical reference materials would allow the glass producers` analytical laboratories to calibrate procedures and instrumentation, to control laboratory performance and conduct self-appraisals, and to help qualify their various waste forms.

  20. Analytical Chemistry Laboratory, progress report for FY 1993

    SciTech Connect

    Not Available

    1993-12-01

    The purpose of this report is to summarize the activities of the Analytical Chemistry Laboratory (ACL) at Argonne National Laboratory (ANL) for Fiscal Year (FY) 1993 (October 1992 through September 1993). This annual report is the tenth for the ACL and describes continuing effort on projects, work on new projects, and contributions of the ACL staff to various programs at ANL. The Analytical Chemistry Laboratory is a full-cost-recovery service center, with the primary mission of providing a broad range of analytical chemistry support services to the scientific and engineering programs at ANL. The ACL also has research programs in analytical chemistry, conducts instrumental and methods development, and provides analytical services for governmental, educational, and industrial organizations. The ACL handles a wide range of analytical problems. Some routine or standard analyses are done, but it is common for the Argonne programs to generate unique problems that require development or modification of methods and adaption of techniques to obtain useful analytical data. The ACL is administratively within the Chemical Technology Division (CMT), its principal ANL client, but provides technical support for many of the technical divisions and programs at ANL. The ACL has four technical groups--Chemical Analysis, Instrumental Analysis, Organic Analysis, and Environmental Analysis--which together include about 45 technical staff members. Talents and interests of staff members cross the group lines, as do many projects within the ACL.