Science.gov

Sample records for identify chemical compounds

  1. Antifungal chemical compounds identified using a C. elegans pathogenicity assay.

    PubMed

    Breger, Julia; Fuchs, Beth Burgwyn; Aperis, George; Moy, Terence I; Ausubel, Frederick M; Mylonakis, Eleftherios

    2007-02-01

    There is an urgent need for the development of new antifungal agents. A facile in vivo model that evaluates libraries of chemical compounds could solve some of the main obstacles in current antifungal discovery. We show that Candida albicans, as well as other Candida species, are ingested by Caenorhabditis elegans and establish a persistent lethal infection in the C. elegans intestinal track. Importantly, key components of Candida pathogenesis in mammals, such as filament formation, are also involved in nematode killing. We devised a Candida-mediated C. elegans assay that allows high-throughput in vivo screening of chemical libraries for antifungal activities, while synchronously screening against toxic compounds. The assay is performed in liquid media using standard 96-well plate technology and allows the study of C. albicans in non-planktonic form. A screen of 1,266 compounds with known pharmaceutical activities identified 15 (approximately 1.2%) that prolonged survival of C. albicans-infected nematodes and inhibited in vivo filamentation of C. albicans. Two compounds identified in the screen, caffeic acid phenethyl ester, a major active component of honeybee propolis, and the fluoroquinolone agent enoxacin exhibited antifungal activity in a murine model of candidiasis. The whole-animal C. elegans assay may help to study the molecular basis of C. albicans pathogenesis and identify antifungal compounds that most likely would not be identified by in vitro screens that target fungal growth. Compounds identified in the screen that affect the virulence of Candida in vivo can potentially be used as "probe compounds" and may have antifungal activity against other fungi. PMID:17274686

  2. A Chemical Screen Identifies Novel Compounds That Overcome Glial-Mediated Inhibition Of Neuronal Regeneration

    PubMed Central

    Usher, Lynn C.; Johnstone, Andrea; Ertürk, Ali; Hu, Ying; Strikis, Dinara; Wanner, Ina B.; Moorman, Sanne; Lee, Jae-Wook; Min, Jaeki; Ha, Hyung-Ho; Duan, Yuanli; Hoffman, Stanley; Goldberg, Jeffrey L.; Bradke, Frank; Chang, Young-Tae; Lemmon, Vance P.; Bixby, John L.

    2010-01-01

    A major barrier to regeneration of central nervous system (CNS) axons is the presence of growth-inhibitory proteins associated with myelin and the glial scar. To identify chemical compounds with the ability to overcome the inhibition of regeneration, we screened a novel triazine library, based on the ability of compounds to increase neurite outgrowth from cerebellar neurons on inhibitory myelin substrates. The screen produced 4 “hit compounds”, which act with nM potency on several different neuronal types, and on several distinct substrates relevant to glial inhibition. Moreover, the compounds selectively overcome inhibition rather than promote growth in general. The compounds do not affect neuronal cAMP levels, PKC activity, or EGFR activation. Interestingly, one of the compounds alters microtubule dynamics and increases microtubule density in both fibroblasts and neurons. This same compound promotes regeneration of dorsal column axons after acute lesions, and potentiates regeneration of optic nerve axons after nerve crush in vivo. These compounds should provide insight into the mechanisms through which glial-derived inhibitors of regeneration act, and could lead to the development of novel therapies for CNS injury. PMID:20357120

  3. Phenotype-driven chemical screening in zebrafish for compounds that inhibit collective cell migration identifies multiple pathways potentially involved in metastatic invasion

    PubMed Central

    Gallardo, Viviana E.; Varshney, Gaurav K.; Lee, Minnkyong; Bupp, Sujata; Xu, Lisha; Shinn, Paul; Crawford, Nigel P.; Inglese, James; Burgess, Shawn M.

    2015-01-01

    ABSTRACT In the last decade, high-throughput chemical screening has become the dominant approach for discovering novel compounds with therapeutic properties. Automated screening using in vitro or cultured cell assays have yielded thousands of candidate drugs for a variety of biological targets, but these approaches have not resulted in an increase in drug discovery despite major increases in expenditures. In contrast, phenotype-driven screens have shown a much stronger success rate, which is why we developed an in vivo assay using transgenic zebrafish with a GFP-marked migrating posterior lateral line primordium (PLLp) to identify compounds that influence collective cell migration. We then conducted a high-throughput screen using a compound library of 2160 annotated bioactive synthetic compounds and 800 natural products to identify molecules that block normal PLLp migration. We identified 165 compounds that interfere with primordium migration without overt toxicity in vivo. Selected compounds were confirmed in their migration-blocking activity by using additional assays for cell migration. We then proved the screen to be successful in identifying anti-metastatic compounds active in vivo by performing orthotopic tumor implantation assays in mice. We demonstrated that the Src inhibitor SU6656, identified in our screen, can be used to suppress the metastatic capacity of a highly aggressive mammary tumor cell line. Finally, we used CRISPR/Cas9-targeted mutagenesis in zebrafish to genetically validate predicted targets of compounds. This approach demonstrates that the migrating PLLp in zebrafish can be used for large-scale, high-throughput screening for compounds that inhibit collective cell migration and, potentially, anti-metastatic compounds. PMID:25810455

  4. Phenotype-driven chemical screening in zebrafish for compounds that inhibit collective cell migration identifies multiple pathways potentially involved in metastatic invasion.

    PubMed

    Gallardo, Viviana E; Varshney, Gaurav K; Lee, Minnkyong; Bupp, Sujata; Xu, Lisha; Shinn, Paul; Crawford, Nigel P; Inglese, James; Burgess, Shawn M

    2015-06-01

    In the last decade, high-throughput chemical screening has become the dominant approach for discovering novel compounds with therapeutic properties. Automated screening using in vitro or cultured cell assays have yielded thousands of candidate drugs for a variety of biological targets, but these approaches have not resulted in an increase in drug discovery despite major increases in expenditures. In contrast, phenotype-driven screens have shown a much stronger success rate, which is why we developed an in vivo assay using transgenic zebrafish with a GFP-marked migrating posterior lateral line primordium (PLLp) to identify compounds that influence collective cell migration. We then conducted a high-throughput screen using a compound library of 2160 annotated bioactive synthetic compounds and 800 natural products to identify molecules that block normal PLLp migration. We identified 165 compounds that interfere with primordium migration without overt toxicity in vivo. Selected compounds were confirmed in their migration-blocking activity by using additional assays for cell migration. We then proved the screen to be successful in identifying anti-metastatic compounds active in vivo by performing orthotopic tumor implantation assays in mice. We demonstrated that the Src inhibitor SU6656, identified in our screen, can be used to suppress the metastatic capacity of a highly aggressive mammary tumor cell line. Finally, we used CRISPR/Cas9-targeted mutagenesis in zebrafish to genetically validate predicted targets of compounds. This approach demonstrates that the migrating PLLp in zebrafish can be used for large-scale, high-throughput screening for compounds that inhibit collective cell migration and, potentially, anti-metastatic compounds. PMID:25810455

  5. Predicting chemically-induced skin reactions. Part I: QSAR models of skin sensitization and their application to identify potentially hazardous compounds.

    PubMed

    Alves, Vinicius M; Muratov, Eugene; Fourches, Denis; Strickland, Judy; Kleinstreuer, Nicole; Andrade, Carolina H; Tropsha, Alexander

    2015-04-15

    Repetitive exposure to a chemical agent can induce an immune reaction in inherently susceptible individuals that leads to skin sensitization. Although many chemicals have been reported as skin sensitizers, there have been very few rigorously validated QSAR models with defined applicability domains (AD) that were developed using a large group of chemically diverse compounds. In this study, we have aimed to compile, curate, and integrate the largest publicly available dataset related to chemically-induced skin sensitization, use this data to generate rigorously validated and QSAR models for skin sensitization, and employ these models as a virtual screening tool for identifying putative sensitizers among environmental chemicals. We followed best practices for model building and validation implemented with our predictive QSAR workflow using Random Forest modeling technique in combination with SiRMS and Dragon descriptors. The Correct Classification Rate (CCR) for QSAR models discriminating sensitizers from non-sensitizers was 71-88% when evaluated on several external validation sets, within a broad AD, with positive (for sensitizers) and negative (for non-sensitizers) predicted rates of 85% and 79% respectively. When compared to the skin sensitization module included in the OECD QSAR Toolbox as well as to the skin sensitization model in publicly available VEGA software, our models showed a significantly higher prediction accuracy for the same sets of external compounds as evaluated by Positive Predicted Rate, Negative Predicted Rate, and CCR. These models were applied to identify putative chemical hazards in the Scorecard database of possible skin or sense organ toxicants as primary candidates for experimental validation. PMID:25560674

  6. Predicting chemically-induced skin reactions. Part I: QSAR models of skin sensitization and their application to identify potentially hazardous compounds

    PubMed Central

    Alves, Vinicius M.; Muratov, Eugene; Fourches, Denis; Strickland, Judy; Kleinstreuer, Nicole; Andrade, Carolina H.; Tropsha, Alexander

    2015-01-01

    Repetitive exposure to a chemical agent can induce an immune reaction in inherently susceptible individuals that leads to skin sensitization. Although many chemicals have been reported as skin sensitizers, there have been very few rigorously validated QSAR models with defined applicability domains (AD) that were developed using a large group of chemically diverse compounds. In this study, we have aimed to compile, curate, and integrate the largest publicly available dataset related to chemically-induced skin sensitization, use this data to generate rigorously validated and QSAR models for skin sensitization, and employ these models as a virtual screening tool for identifying putative sensitizers among environmental chemicals. We followed best practices for model building and validation implemented with our predictive QSAR workflow using random forest modeling technique in combination with SiRMS and Dragon descriptors. The Correct Classification Rate (CCR) for QSAR models discriminating sensitizers from non-sensitizers were 71–88% when evaluated on several external validation sets, within a broad AD, with positive (for sensitizers) and negative (for non-sensitizers) predicted rates of 85% and 79% respectively. When compared to the skin sensitization module included in the OECD QSAR toolbox as well as to the skin sensitization model in publicly available VEGA software, our models showed a significantly higher prediction accuracy for the same sets of external compounds as evaluated by Positive Predicted Rate, Negative Predicted Rate, and CCR. These models were applied to identify putative chemical hazards in the ScoreCard database of possible skin or sense organ toxicants as primary candidates for experimental validation. PMID:25560674

  7. Devices for collecting chemical compounds

    DOEpatents

    Scott, Jill R; Groenewold, Gary S

    2013-12-24

    A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from a fixed surface so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

  8. Automated compound classification using a chemical ontology

    PubMed Central

    2012-01-01

    Background Classification of chemical compounds into compound classes by using structure derived descriptors is a well-established method to aid the evaluation and abstraction of compound properties in chemical compound databases. MeSH and recently ChEBI are examples of chemical ontologies that provide a hierarchical classification of compounds into general compound classes of biological interest based on their structural as well as property or use features. In these ontologies, compounds have been assigned manually to their respective classes. However, with the ever increasing possibilities to extract new compounds from text documents using name-to-structure tools and considering the large number of compounds deposited in databases, automated and comprehensive chemical classification methods are needed to avoid the error prone and time consuming manual classification of compounds. Results In the present work we implement principles and methods to construct a chemical ontology of classes that shall support the automated, high-quality compound classification in chemical databases or text documents. While SMARTS expressions have already been used to define chemical structure class concepts, in the present work we have extended the expressive power of such class definitions by expanding their structure-based reasoning logic. Thus, to achieve the required precision and granularity of chemical class definitions, sets of SMARTS class definitions are connected by OR and NOT logical operators. In addition, AND logic has been implemented to allow the concomitant use of flexible atom lists and stereochemistry definitions. The resulting chemical ontology is a multi-hierarchical taxonomy of concept nodes connected by directed, transitive relationships. Conclusions A proposal for a rule based definition of chemical classes has been made that allows to define chemical compound classes more precisely than before. The proposed structure-based reasoning logic allows to translate chemistry expert knowledge into a computer interpretable form, preventing erroneous compound assignments and allowing automatic compound classification. The automated assignment of compounds in databases, compound structure files or text documents to their related ontology classes is possible through the integration with a chemical structure search engine. As an application example, the annotation of chemical structure files with a prototypic ontology is demonstrated. PMID:23273256

  9. Chemically engineered extracts: source of bioactive compounds.

    PubMed

    Ramallo, I Ayelen; Salazar, Mario O; Mendez, Luciana; Furlan, Ricardo L E

    2011-04-19

    Biological research and drug discovery critically depend on access to libraries of small molecules that have an affinity for biomacromolecules. By virtue of their sustained success as sources of lead compounds, natural products are recognized as "privileged" starting points in structural space for library development. Compared with synthetic compounds, natural products have distinguishing structural properties; indeed, researchers have begun to quantify and catalog the differences between the two classes of molecules. Measurable differences in the number of chiral centers, the degree of saturation, the presence of aromatic rings, and the number of the various heteroatoms are among the chief distinctions between natural and synthetic compounds. Natural products also include a significant proportion of recurring molecular scaffolds that are not present in currently marketed drugs: the bioactivity of these natural substructures has been refined over the long process of evolution. In this Account, we present our research aimed at preparing libraries of semisynthetic compounds, or chemically engineered extracts (CEEs), through chemical diversification of natural products mixtures. The approach relies on the power of numbers, that is, in the chemical alteration of a sizable fraction of the starting complex mixture. Major changes in composition can be achieved through the chemical transformation of reactive molecular fragments that are found in most natural products. If such fragments are common enough, their transformation represents an entry point for chemically altering a high proportion of the components of crude natural extracts. We have searched for common reactive fragments in the Dictionary of Natural Products (CRC Press) and identified several functional groups that are expected to be present in a large fraction of the components of an average natural crude extract. To date, we have used reactions that incorporate (i) nitrogen atoms through carbonyl groups, (ii) sulfur by transformation of -OH and amines, and (iii) bromine through double bonds and aromatic rings. The resulting CEEs had different composition and biomolecular properties than their natural progenitors. We isolated a semisynthetic ?-glucosidase inhibitor from a CEE prepared by reaction with benzenesulfonyl chloride, an antifungal pyrazole from a CEE prepared by reaction with hydrazine, and an acetylcholinesterase inhibitor from a CEE prepared through bromination. Our results illustrate how biological activity can be generated through chemical diversification of natural product mixtures. Moreover, the level of control that can be asserted in the process by judicious design and experimental choices underscores the potential for further development of CEEs in both basic research and drug discovery. PMID:21355557

  10. Cheminformatics Analysis of EPA ToxCast Chemical Libraries to Identify Domains of Applicability for Predictive Toxicity Models and Prioritize Compounds for Toxicity Testing

    EPA Science Inventory

    An important goal of toxicology research is the development of robust methods that use in vitro and chemical structure information to predict in vivo toxicity endpoints. The US EPA ToxCast program is addressing this goal using ~600 in vitro assays to create bioactivity profiles o...

  11. Identifying developmental vascular disruptor compounds using a predictive signature and alternative toxicity models

    EPA Science Inventory

    Identifying Developmental Vascular Disruptor Compounds Using a Predictive Signature and Alternative Toxicity Models Presenting Author: Tamara Tal Affiliation: U.S. EPA/ORD/ISTD, RTP, NC, USA Chemically induced vascular toxicity during embryonic development can result in a wide...

  12. Chemical compound navigator: a web-based chem-BLAST, chemical taxonomy-based search engine for browsing compounds.

    PubMed

    Prasanna, M D; Vondrasek, Jiri; Wlodawer, Alexander; Rodriguez, H; Bhat, T N

    2006-06-01

    A novel technique to annotate, query, and analyze chemical compounds has been developed and is illustrated by using the inhibitor data on HIV protease-inhibitor complexes. In this method, all chemical compounds are annotated in terms of standard chemical structural fragments. These standard fragments are defined by using criteria, such as chemical classification; structural, chemical, or functional groups; and commercial, scientific or common names or synonyms. These fragments are then organized into a data tree based on their chemical substructures. Search engines have been developed to use this data tree to enable query on inhibitors of HIV protease (http://xpdb.nist.gov/hivsdb/hivsdb.html). These search engines use a new novel technique, Chemical Block Layered Alignment of Substructure Technique (Chem-BLAST) to search on the fragments of an inhibitor to look for its chemical structural neighbors. This novel technique to annotate and query compounds lays the foundation for the use of the Semantic Web concept on chemical compounds to allow end users to group, sort, and search structural neighbors accurately and efficiently. During annotation, it enables the attachment of "meaning" (i.e., semantics) to data in a manner that far exceeds the current practice of associating "metadata" with data by creating a knowledge base (or ontology) associated with compounds. Intended users of the technique are the research community and pharmaceutical industry, for which it will provide a new tool to better identify novel chemical structural neighbors to aid drug discovery. PMID:16508960

  13. Quantum chemical studies of estrogenic compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantum chemical methods are potent tools to provide information on the chemical structure and electronic properties of organic molecules. Modern computational chemistry methods have provided a great deal of insight into the binding of estrogenic compounds to estrogenic receptors (ER), an important ...

  14. Identifying chemicals that are planetary boundary threats.

    PubMed

    MacLeod, Matthew; Breitholtz, Magnus; Cousins, Ian T; de Wit, Cynthia A; Persson, Linn M; Rudén, Christina; McLachlan, Michael S

    2014-10-01

    Rockström et al. proposed a set of planetary boundaries that delimit a "safe operating space for humanity". Many of the planetary boundaries that have so far been identified are determined by chemical agents. Other chemical pollution-related planetary boundaries likely exist, but are currently unknown. A chemical poses an unknown planetary boundary threat if it simultaneously fulfills three conditions: (1) it has an unknown disruptive effect on a vital Earth system process; (2) the disruptive effect is not discovered until it is a problem at the global scale, and (3) the effect is not readily reversible. In this paper, we outline scenarios in which chemicals could fulfill each of the three conditions, then use the scenarios as the basis to define chemical profiles that fit each scenario. The chemical profiles are defined in terms of the nature of the effect of the chemical and the nature of exposure of the environment to the chemical. Prioritization of chemicals in commerce against some of the profiles appears feasible, but there are considerable uncertainties and scientific challenges that must be addressed. Most challenging is prioritizing chemicals for their potential to have a currently unknown effect on a vital Earth system process. We conclude that the most effective strategy currently available to identify chemicals that are planetary boundary threats is prioritization against profiles defined in terms of environmental exposure combined with monitoring and study of the biogeochemical processes that underlie vital Earth system processes to identify currently unknown disruptive effects. PMID:25181298

  15. IDENTIFYING CHEMICAL COMPOUNDS IN THE ENVIRONMENT

    EPA Science Inventory

    The quality of drinking and recreational water is currently ascertained using indicator bacteria. The tests to analyze for these bacteria require a considerable length of time to complete, and do not discriminate between human and animal fecal material sources. To shorten the t...

  16. USING AN ACCURATE MASS, TRIPLE QUADRUPOLE MASS SPECTROMETER AND AN ION CORRELATION PROGRAM TO IDENTIFY COMPOUNDS

    EPA Science Inventory

    Most compounds are not found in mass spectral libraries and must be identified by other means. Often, compound identities can be deduced from the compositions of the ions in their mass spectra and review of the chemical literature. Confirmation is provided by mass spectra and r...

  17. Chemical defenses: from compounds to communities.

    PubMed

    Paul, Valerie J; Arthur, Karen E; Ritson-Williams, Raphael; Ross, Cliff; Sharp, Koty

    2007-12-01

    Marine natural products play critical roles in the chemical defense of many marine organisms and in some cases can influence the community structure of entire ecosystems. Although many marine natural products have been studied for biomedical activity, yielding important information about their biochemical effects and mechanisms of action, much less is known about ecological functions. The way in which marine consumers perceive chemical defenses can influence their health and survival and determine whether some natural products persist through a food chain. This article focuses on selected marine natural products, including okadaic acid, brevetoxins, lyngbyatoxin A, caulerpenyne, bryostatins, and isocyano terpenes, and examines their biosynthesis (sometimes by symbiotic microorganisms), mechanisms of action, and biological and ecological activity. We selected these compounds because their impacts on marine organisms and communities are some of the best-studied among marine natural products. We discuss the effects of these compounds on consumer behavior and physiology, with an emphasis on neuroecology. In addition to mediating a variety of trophic interactions, these compounds may be responsible for community-scale ecological impacts of chemically defended organisms, such as shifts in benthic and pelagic community composition. Our examples include harmful algal blooms; the invasion of the Mediterranean by Caulerpa taxifolia; overgrowth of coral reefs by chemically rich macroalgae and cyanobacteria; and invertebrate chemical defenses, including the role of microbial symbionts in compound production. PMID:18083964

  18. Lifetime of a Chemically Bound Helium Compound

    NASA Technical Reports Server (NTRS)

    Chaban, Galina M.; Lundell, Jan; Gerber, R. Benny; Kwak, Dochan (Technical Monitor)

    2001-01-01

    The rare-gas atoms are chemically inert, to an extent unique among all elements. This is due to the stable electronic structure of the atoms. Stable molecules with chemically bound rare-gas atoms are, however, known. A first such compound, XePtF6, W2S prepared in 1962 and since then a range of molecules containing radon, xenon and krypton have been obtained. Most recently, a first stable chemically bound compound of argon was prepared, leaving neon and helium as the only elements for which stable chemically bound molecules are not yet known. Electronic structure calculations predict that a metastable species HHeF exists, but significance of the result depends on the unknown lifetime. Here we report quantum dynamics calculations of the lifetime of HHeF, using accurate interactions computed from electronic structure theory. HHeF is shown to disintegrate by tunneling through energy barriers into He + HF and H + He + F the first channel greatly dominating. The lifetime of HHeF is more than 120 picoseconds, that of DHeF is 14 nanoseconds. The relatively long lifetimes are encouraging for the preparation prospects of this first chemically bound helium compound.

  19. Microfluidic in vivo screen identifies compounds enhancing neuronal

    E-print Network

    Haggarty, Stephen J.

    Compound screening is a powerful tool to identify new therapeutic targets, drug leads, and elucidate the fundamental mechanisms of biological processes. We report here the results of the first in vivo small-molecule screens ...

  20. Exposure Levels for Chemical Threat Compounds; Information to Facilitate Chemical Incident Response

    SciTech Connect

    Hauschild, Veronique; Watson, Annetta Paule

    2013-01-01

    Exposure Standards, Limits and Guidelines for Chemical Threat Compunds ABSTRACT Exposure criteria for chemical warfare (CW) agents and certain toxic industrial chemicals (TICs) used as CW agents (such as chlorine fill in an improvised explosive device) have been developed for protection of the civilian general public, civilian employees in chemical agent processing facilities and deployed military populations. In addition, compound-specific concentrations have been developed to serve as how clean is clean enough clearance criteria guiding facility recovery following chemical terrorist or other hazardous release events. Such criteria are also useful to verify compound absence, identify containment boundaries and expedite facility recovery following chemical threat release. There is no single right value or concentration appropriate for all chemical hazard control applications. It is acknowledged that locating and comparing the many sources of CW agent and TIC exposure criteria has not been previously well-defined. This paper summarizes many of these estimates and assembles critical documentation regarding their derivation and use.

  1. Chemical Trends for Transition Metal Compound Bonding to Graphene

    NASA Astrophysics Data System (ADS)

    Lange, Bjoern; Blum, Volker

    2015-03-01

    Transition metal compounds are of interest as catalysts for the hydrogen evolution reaction (HER). However, a perfect candidate to replace expensive platinum has not yet been identified. To tailor a specific compound, several properties come into play. One is the bonding to the underlying substrate, for which ?-bonded carbon nanostructures are promising candidates. Here we analyze the bonding of small transition metal compound nanoclusters to a graphene layer for a range of chemical compositions: MxAy (M = Mo, Ti; A = S, O, B, N, C). The clusters are generated by an unbiased random search algorithm. We perform total energy calculations based on density functional theory to identify lowest energy clusters. We calculate binding energies using the PBE and HSE functionals with explicit van der Waals treatment and benchmark those against RPA cluster calculations. Our results indicate that molybdenum-carbides and -nitrides tend to bond tightly to graphene. Mo-oxides and -sulfides show small binding energies, indicating van der Waals bonding.

  2. ION COMPOSITION ELUCIDATION (ICE): A HIGH RESOLUTION MASS SPECTROMETRIC TECHNIQUE FOR IDENTIFYING COMPOUNDS IN COMPLEX MIXTURES

    EPA Science Inventory

    When tentatively identifying compounds in complex mixtures using mass spectral libraries, multiple matches or no plausible matches due to a high level of chemical noise or interferences can occur. Worse yet, most analytes are not in the libraries. In each case, Ion Composition El...

  3. Chemical Proteomic Platform To Identify Citrullinated Proteins.

    PubMed

    Lewallen, Daniel M; Bicker, Kevin L; Subramanian, Venkataraman; Clancy, Kathleen W; Slade, Daniel J; Martell, Julianne; Dreyton, Christina J; Sokolove, Jeremy; Weerapana, Eranthie; Thompson, Paul R

    2015-11-20

    Anti-citrullinated protein antibodies (ACPAs) are a hallmark of rheumatoid arthritis (RA) and are routinely used for disease diagnosis. Protein citrullination is also increased in cancer and other autoimmune disorders, suggesting that citrullinated proteins may serve as biomarkers for diseases beyond RA. To identify these citrullinated proteins, we developed biotin-conjugated phenylglyoxal (biotin-PG). Using this probe and our platform technology, we identified >50 intracellular citrullinated proteins. More than 20 of these are involved in RNA splicing, suggesting, for the first time, that citrullination modulates RNA biology. Overall, this chemical proteomic platform will play a key role in furthering our understanding of protein citrullination in rheumatoid arthritis and potentially a wider spectrum of inflammatory diseases. PMID:26360112

  4. Device for collecting chemical compounds and related methods

    DOEpatents

    Scott, Jill R.; Groenewold, Gary S.; Rae, Catherine

    2013-01-01

    A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from the fixed surfaces so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

  5. Chemical Genetics: Elucidating Biological Systems with Small-Molecule Compounds

    E-print Network

    Nghiem, Paul

    Chemical Genetics: Elucidating Biological Systems with Small-Molecule Compounds Masaoki Kawasumi1 and Paul Nghiem1,2 Chemical genetics employs diverse small-molecule compounds to elucidate biological chemical genetic approach, whereas the reverse approach involves small molecules targeting a single protein

  6. How can Databases assist with the Prediction of Chemical Compounds?

    PubMed Central

    Schön, J Christian

    2014-01-01

    An overview is given on the ways databases can be employed to aid in the prediction of chemical compounds, in particular inorganic crystalline compounds. Methods currently employed and possible future approaches are discussed. PMID:26213422

  7. High-throughput screening identifies compounds that enhance lentiviral transduction.

    PubMed

    Johnston, J M; Denning, G; Moot, R; Whitehead, D; Shields, J; Le Doux, J M; Doering, C B; Spencer, H T

    2014-12-01

    A difficulty in the field of gene therapy is the need to increase the susceptibility of hematopoietic stem cells (HSCs) to ex vivo genetic manipulation. To overcome this obstacle a high-throughput screen was performed to identify compounds that could enhance the transduction of target cells by lentiviral vectors. Of the 1280 compounds initially screened using the myeloid-erythroid-leukemic K562 cell line, 30 were identified as possible enhancers of viral transduction. Among the positive hits were known enhancers of transduction (camptothecin, etoposide and taxol), as well as the previously unidentified phorbol 12-myristate 13-acetate (PMA). The percentage of green fluorescent protein (GFP)-positive-expressing K562 cells was increased more than fourfold in the presence of PMA. In addition, the transduction of K562 cells with a lentiviral vector encoding fVIII was four times greater in the presence of PMA as determined by an increase in the levels of provirus in genetically modified cells. PMA did not enhance viral transduction of all cell types (for example, sca-1(+) mouse hematopoietic cells) but did enhance viral transduction of human bone marrow-derived CD34(+) cells. Notably, the percentage of GFP-positive CD34(+) cells was increased from 7% in the absence of PMA to greater than 22% in the presence of 1?nM PMA. PMA did not affect colony formation of CD34(+) cells or the expression of the hematopoietic markers CD34 and CD45. These data demonstrate that high-throughput screening can be used to identify compounds that increase the transduction efficiency of lentiviral vectors, identifying PMA as a potential enhancer of lentiviral HSC transduction. PMID:25231175

  8. High Content Screening of Diverse Compound Libraries Identifies Potent Modulators of Tubulin Dynamics

    PubMed Central

    2014-01-01

    Tubulin modulating agents such as the taxanes are among the most effective antimitotic cancer drugs, although resistance and toxicity present significant problems in their clinical use. However, most tubulin modulators are derived from complex natural products, which can make modification of their structure to address these problems difficult. Here, we report the discovery of new antimitotic compounds with simple structures that can be rapidly synthesized, through the phenotypic screening of a diverse compound library for the induction of mitotic arrest. We first identified a compound, which induced mitotic arrest in human cells at submicromolar concentrations. Its simple structure enabled rapid exploration of activity, defining a biphenylacetamide moiety required for activity, A family of analogues was synthesized, yielding optimized compounds that caused mitotic arrest and cell death in the low nanomolar range, comparable to clinically used antimitotic agents. These compounds can be synthesized in 1–3 steps and good yields. We show that one such compound targets tubulin, partially inhibiting colchicine but not vinblastine binding, suggesting that it acts allosterically to the known colchicine-binding site. Thus, our results exemplify the use of phenotypic screening to identify novel antimitotic compounds from diverse chemical libraries and characterize a family of biphenylacetamides (biphenabulins) that show promise for further development. PMID:24900887

  9. Development of an electronic nose to identify and quantify volatile hazardous compounds.

    PubMed

    Fernandes, Daniel L A; Gomes, M Teresa S R

    2008-10-19

    A new electronic nose was developed to identify the chemical compound released when a 2.5-L flask was broken inside a 3 m x 3 m x 2.5 m store-room. Flasks of 10 different hazardous compounds were initially present in the room: ammonia, propanone, hexane, acetic acid, toluene, methanol, tetrachloromethane, chloroform, ethanol and dichloromethane. Besides identification, quantification of the compound present in the air was also performed by the electronic nose, in order to evaluate the risk level for room cleaning. An array of six sensors based on coated piezoelectric quartz crystals was used. Although none of the individual sensors was specific for a single compound, an artificial neural network made it possible to identify and quantify the released vapour, among a series of 10 compounds, with six sensors. The neural network could be simplified, and the number of neurons reduced, provided it was used just for the identification task. Quantification could be performed later using the individual calibration of the sensor most sensitive to the identified compound. PMID:18804602

  10. Structure-based drug design identifies polythiophenes as antiprion compounds.

    PubMed

    Herrmann, Uli S; Schütz, Anne K; Shirani, Hamid; Huang, Danzhi; Saban, Dino; Nuvolone, Mario; Li, Bei; Ballmer, Boris; Åslund, Andreas K O; Mason, Jeffrey J; Rushing, Elisabeth; Budka, Herbert; Nyström, Sofie; Hammarström, Per; Böckmann, Anja; Caflisch, Amedeo; Meier, Beat H; Nilsson, K Peter R; Hornemann, Simone; Aguzzi, Adriano

    2015-08-01

    Prions cause transmissible spongiform encephalopathies for which no treatment exists. Prions consist of PrP(Sc), a misfolded and aggregated form of the cellular prion protein (PrP(C)). We explore the antiprion properties of luminescent conjugated polythiophenes (LCPs) that bind and stabilize ordered protein aggregates. By administering a library of structurally diverse LCPs to the brains of prion-infected mice via osmotic minipumps, we found that antiprion activity required a minimum of five thiophene rings bearing regularly spaced carboxyl side groups. Solid-state nuclear magnetic resonance analyses and molecular dynamics simulations revealed that anionic side chains interacted with complementary, regularly spaced cationic amyloid residues of model prions. These findings allowed us to extract structural rules governing the interaction between LCPs and protein aggregates, which we then used to design a new set of LCPs with optimized binding. The new set of LCPs showed robust prophylactic and therapeutic potency in prion-infected mice, with the lead compound extending survival by >80% and showing activity against both mouse and hamster prions as well as efficacy upon intraperitoneal administration into mice. These results demonstrate the feasibility of targeted chemical design of compounds that may be useful for treating diseases of aberrant protein aggregation such as prion disease. PMID:26246168

  11. Hedonic Judgments of Chemical Compounds Are Correlated with Molecular Size

    PubMed Central

    Zarzo, Manuel

    2011-01-01

    Different psychophysical works have reported that, when a wide range of odors is assessed, the hedonic dimension is the most salient. Hence, pleasantness is the most basic attribute of odor perception. Recent studies suggest that the molecular size of a given odorant is positively correlated with its hedonic character. This correlation was confirmed in the present study, but further basic molecular features affecting pleasantness were identified by means of multiple linear regression for the compounds contained in five chemical sets. For three of them, hedonic judgments are available in the literature. For a further two chemical sets, hedonic scores were estimated from odor character descriptions based on numerical profiles. Generally speaking, fairly similar equations were obtained for the prediction of hedonic judgments in the five chemical sets, with R2 values ranging from 0.46 to 0.71. The results suggest that larger molecules containing oxygen are more likely to be perceived as pleasant, while the opposite applies to carboxylic acids and sulfur compounds. PMID:22163815

  12. Process for preparing a chemical compound enriched in isotope content

    DOEpatents

    Michaels, Edward D. (Spring Valley, OH)

    1982-01-01

    A process to prepare a chemical enriched in isotope content which includes: (a) A chemical exchange reaction between a first and second compound which yields an isotopically enriched first compound and an isotopically depleted second compound; (b) the removal of a portion of the first compound as product and the removal of a portion of the second compound as spent material; (c) the conversion of the remainder of the first compound to the second compound for reflux at the product end of the chemical exchange reaction region; (d) the conversion of the remainder of the second compound to the first compound for reflux at the spent material end of the chemical exchange region; and the cycling of the additional chemicals produced by one conversion reaction to the other conversion reaction, for consumption therein. One of the conversion reactions is an oxidation reaction, and the energy that it yields is used to drive the other conversion reaction, a reduction. The reduction reaction is carried out in a solid polymer electrolyte electrolytic reactor. The overall process is energy efficient and yields no waste by-products.

  13. Can Zebrafish be used to Identify Developmentally Neurotoxic Chemicals

    EPA Science Inventory

    Can Zebrafish be Used to Identify Developmentally Neurotoxic Chemicals? The U.S. Environmental Protection Agency is evaluating methods to screen and prioritize large numbers of chemicals for developmental neurotoxicity. We are exploring behavioral methods using zebrafish by desig...

  14. Artificial neural network cascade identifies multi-P450 inhibitors in natural compounds

    PubMed Central

    Li, Zhangming; Li, Yan; Sun, Lu; Tang, Yun; Liu, Lanru

    2015-01-01

    Substantial evidence has shown that most exogenous substances are metabolized by multiple cytochrome P450 (P450) enzymes instead of by merely one P450 isoform. Thus, multi-P450 inhibition leads to greater drug-drug interaction risk than specific P450 inhibition. Herein, we innovatively established an artificial neural network cascade (NNC) model composed of 23 cascaded networks in a ladder-like framework to identify potential multi-P450 inhibitors among natural compounds by integrating 12 molecular descriptors into a P450 inhibition score (PIS). Experimental data reporting in vitro inhibition of five P450 isoforms (CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) were obtained for 8,148 compounds from the Cytochrome P450 Inhibitors Database (CPID). The results indicate significant positive correlation between the PIS values and the number of inhibited P450 isoforms (Spearman’s ? = 0.684, p < 0.0001). Thus, a higher PIS indicates a greater possibility for a chemical to inhibit the enzyme activity of at least three P450 isoforms. Ten-fold cross-validation of the NNC model suggested an accuracy of 78.7% for identifying whether a compound is a multi-P450 inhibitor or not. Using our NNC model, 22.2% of the approximately 160,000 natural compounds in TCM Database@Taiwan were identified as potential multi-P450 inhibitors. Furthermore, chemical similarity calculations suggested that the prevailing parent structures of natural multi-P450 inhibitors were alkaloids. Our findings show that dissection of chemical structure contributes to confident identification of natural multi-P450 inhibitors and provides a feasible method for virtually evaluating multi-P450 inhibition risk for a known structure. PMID:26719820

  15. Strategies and future trends to identify the mode of action of phytotoxic compounds.

    PubMed

    Tresch, Stefan

    2013-11-01

    Small molecules affecting plant processes have been widely used as probes to study basic physiology. In agricultural practices some of these molecules have served as herbicides or plant growth regulators. Historically, most of the compounds were identified in large screens by the agrochemical industry, but also as phytoactive natural products. More recently, novel phytoactive compounds originated from academic research by chemical screens performed to induce specific phenotypes of interest. In the present review different approaches were evaluated for the identification of the mode of action (MoA) of phytoactive compounds. Based on the methodologies used for MoA identification, three approaches are differentiated: a phenotyping approach, an approach based on a genetic screen and a biochemical screening approach. Target sites of compounds targeting primary or secondary metabolism were identified most successfully with a phenotyping approach. Target sites for compounds that influence cell structure, such as cell wall biosynthesis or the cytoskeleton, or compounds that interact with the hormone system, were in most cases discovered by using a genetic approach. Examples showing the strengths and weaknesses of the different approaches are discussed in detail. Additionally, new techniques that could contribute to future MoA identification projects are reviewed. In particular, next-generation sequencing techniques may be used for the fast-forward mapping of mutants identified in genetic screens. Finally, a revised three-tiered approach for the MoA identification of phytoactive compounds is proposed. The approach consists of a 1st tier, which addresses compound stability, uniformity of effects in different species, general cytotoxicity and the effect on common processes such as transcription and translation. Advanced studies based on these findings initiate the 2nd tier MoA characterization, either with further phenotypic characterization, starting a genetic screen or establishing a biochemical screen. At the 3rd tier, enzyme assays or protein affinity studies should show the activity of the compound on the hypothesized target and should associate the in vitro effects with the in vivo profile of the compound. PMID:24094055

  16. Helping Students Distinguish between Mixtures and Chemical Compounds.

    ERIC Educational Resources Information Center

    Papageorgiou, George

    2002-01-01

    Describes a model demonstrating the difference between mixtures and chemical compounds in which two different colors of clay are used to represent two different elements. Makes connections to real world situations. (YDS)

  17. Studying a Drug-like, RNA-Focused Small Molecule Library Identifies Compounds That Inhibit RNA Toxicity in Myotonic Dystrophy.

    PubMed

    Rzuczek, Suzanne G; Southern, Mark R; Disney, Matthew D

    2015-12-18

    There are many RNA targets in the transcriptome to which small molecule chemical probes and lead therapeutics are desired. However, identifying compounds that bind and modulate RNA function in cellulo is difficult. Although rational design approaches have been developed, they are still in their infancies and leave many RNAs "undruggable". In an effort to develop a small molecule library that is biased for binding RNA, we computationally identified "drug-like" compounds from screening collections that have favorable properties for binding RNA and for suitability as lead drugs. As proof-of-concept, this collection was screened for binding to and modulating the cellular dysfunction of the expanded repeating RNA (r(CUG)(exp)) that causes myotonic dystrophy type 1. Hit compounds bind the target in cellulo, as determined by the target identification approach Competitive Chemical Cross-Linking and Isolation by Pull-down (C-ChemCLIP), and selectively improve several disease-associated defects. The best compounds identified from our 320-member library are more potent in cellulo than compounds identified by high-throughput screening (HTS) campaigns against this RNA. Furthermore, the compound collection has a higher hit rate (9% compared to 0.01-3%), and the bioactive compounds identified are not charged; thus, RNA can be "drugged" with compounds that have favorable pharmacological properties. Finally, this RNA-focused small molecule library may serve as a useful starting point to identify lead "drug-like" chemical probes that affect the biological (dys)function of other RNA targets by direct target engagement. PMID:26414664

  18. 30 CFR 47.21 - Identifying hazardous chemicals.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... standards in 30 CFR chapter I. (3) Occupational Safety and Health Administration (OSHA), 29 CFR part 1910... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Identifying hazardous chemicals. 47.21 Section... TRAINING HAZARD COMMUNICATION (HazCom) Hazard Determination § 47.21 Identifying hazardous chemicals....

  19. 30 CFR 47.21 - Identifying hazardous chemicals.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... standards in 30 CFR chapter I. (3) Occupational Safety and Health Administration (OSHA), 29 CFR part 1910... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Identifying hazardous chemicals. 47.21 Section... TRAINING HAZARD COMMUNICATION (HazCom) Hazard Determination § 47.21 Identifying hazardous chemicals....

  20. 30 CFR 47.21 - Identifying hazardous chemicals.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... standards in 30 CFR chapter I. (3) Occupational Safety and Health Administration (OSHA), 29 CFR part 1910... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Identifying hazardous chemicals. 47.21 Section... TRAINING HAZARD COMMUNICATION (HazCom) Hazard Determination § 47.21 Identifying hazardous chemicals....

  1. 30 CFR 47.21 - Identifying hazardous chemicals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... standards in 30 CFR chapter I. (3) Occupational Safety and Health Administration (OSHA), 29 CFR part 1910... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Identifying hazardous chemicals. 47.21 Section... TRAINING HAZARD COMMUNICATION (HazCom) Hazard Determination § 47.21 Identifying hazardous chemicals....

  2. 30 CFR 47.21 - Identifying hazardous chemicals.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... standards in 30 CFR chapter I. (3) Occupational Safety and Health Administration (OSHA), 29 CFR part 1910... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Identifying hazardous chemicals. 47.21 Section... TRAINING HAZARD COMMUNICATION (HazCom) Hazard Determination § 47.21 Identifying hazardous chemicals....

  3. Compounds with species and cell type specific toxicity identified in a 2,000 compound drug screen of neural stem cells and rat mixed cortical neurons

    PubMed Central

    Malik, Nasir; Efthymiou, Anastasia G.; Mather, Karly; Chester, Nathaniel; Wang, Xiantao; Nath, Avindra; Rao, Mahendra S.; Steiner, Joseph P.

    2015-01-01

    Human primary neural tissue is a vital component for the quick and simple determination of chemical compound neurotoxicity in vitro. In particular, such tissue would be ideal for high-throughput screens that can be used to identify novel neurotoxic or neurotherapeutic compounds. We have previously established a high-throughput screening platform using human induced pluripotent stem cell (iPSC)-derived neural stem cells (NSCs) and neurons. In this study, we conducted a 2,000 compound screen with human NSCs and rat cortical cells to identify compounds that are selectively toxic to each group. Approximately 100 of the tested compounds showed specific toxicity to human NSCs. A secondary screen of a small subset of compounds from the primary screen on human iPSCs, NSC-derived neurons, and fetal astrocytes validated the results from >80% of these compounds with some showing cell specific toxicity. Amongst those compounds were several cardiac glycosides, all of which were selectively toxic to the human cells. As the screen was able to reliably identify neurotoxicants, many with species and cell-type specificity, this study demonstrates the feasibility of this NSC-driven platform for higher-throughput neurotoxicity screens. PMID:25454721

  4. A Yeast Chemical Genetic Screen Identifies Inhibitors of Human Telomerase

    PubMed Central

    Wong, Lai Hong; Unciti-Broceta, Asier; Spitzer, Michaela; White, Rachel; Tyers, Mike; Harrington, Lea

    2013-01-01

    Summary Telomerase comprises a reverse transcriptase and an internal RNA template that maintains telomeres in many eukaryotes, and it is a well-validated cancer target. However, there is a dearth of small molecules with efficacy against human telomerase in vivo. We developed a surrogate yeast high-throughput assay to identify human telomerase inhibitors. The reversibility of growth arrest induced by active human telomerase was assessed against a library of 678 compounds preselected for bioactivity in S. cerevisiae. Four of eight compounds identified reproducibly restored growth to strains expressing active human telomerase, and three of these four compounds also specifically inhibited purified human telomerase in vitro. These compounds represent probes for human telomerase function, and potential entry points for development of lead compounds against telomerase-positive cancers. PMID:23521791

  5. (The Futility of) Trying to Predict Carcinogenicity of Chemical Compounds

    E-print Network

    Pfahringer, Bernhard

    (The Futility of) Trying to Predict Carcinogenicity of Chemical Compounds Bernhard Pfahringer Toxicology Challenge 2001. The challenge is to predict the carcinogenicity of chemicals based on structural conclude that reliable prediction of carcinogenicity is still a far away goal. 1 Introduction

  6. LOSS OF ORGANIC CHEMICALS IN SOIL: PURE COMPOUND TREATABILITY STUDIES

    EPA Science Inventory

    Comprehensive screening data on the treatability of 32 organic chemicals in soil were developed. Of the evaluated chemicals, 22 were phenolic compounds. Aerobic batch laboratory microcosm experiments were conducted using two soils: an acidic clay soil with <1% organic matter and ...

  7. Thermodynamic analysis of chemical compatibility of several compounds with Fe-Cr-Al alloys

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.

    1993-01-01

    Chemical compatibility between Fe-19.8Cr-4.8Al (weight percent), which is the base composition for the commercial superalloy MA956, and several carbides, borides, nitrides, oxides, and silicides was analyzed from thermodynamic considerations. The effect of addition of minor alloying elements, such as Ti, Y, and Y2O3, to the Fe-Cr-Al alloy on chemical compatibility between the alloy and various compounds was also analyzed. Several chemically compatible compounds that can be potential reinforcement materials and/or interface coating materials for Fe-Cr-Al based composites were identified.

  8. The Use of Chemical-Chemical Interaction and Chemical Structure to Identify New Candidate Chemicals Related to Lung Cancer

    PubMed Central

    Zheng, Mingyue; Kong, Xiangyin; Huang, Tao; Cai, Yu-Dong

    2015-01-01

    Lung cancer causes over one million deaths every year worldwide. However, prevention and treatment methods for this serious disease are limited. The identification of new chemicals related to lung cancer may aid in disease prevention and the design of more effective treatments. This study employed a weighted network, constructed using chemical-chemical interaction information, to identify new chemicals related to two types of lung cancer: non-small lung cancer and small-cell lung cancer. Then, a randomization test as well as chemical-chemical interaction and chemical structure information were utilized to make further selections. A final analysis of these new chemicals in the context of the current literature indicates that several chemicals are strongly linked to lung cancer. PMID:26047514

  9. IDENTIFYING COMPOUNDS DESPITE CHROMATOGRAPHY LIMITATIONS: ORGANOPHOSPHATES IN TREATED SEWAGE

    EPA Science Inventory

    Highly concentrated extracts of sewage treatment plant (STP) effluents contain detectable
    levels of dozens of compounds resulting from human activities. Recent concern over use and
    disposal of Pharmaceuticals and Personal Care Products (PPCPS) (1) has stimulated interest ...

  10. Experimental Studies of the Universal Chemical Key (UCK) Algorithm on the NCI Database of Chemical Compounds

    E-print Network

    Grossman, Robert

    Experimental Studies of the Universal Chemical Key (UCK) Algorithm on the NCI Database of Chemical the Universal Chemical Key (UCK) algorithm that constructs a unique key for a molecular structure. The molecular and the bonds representing the edges. The algorithm was tested on 236,917 compounds obtained from the National

  11. Sensitive markers used to identify compounds that trigger apoptosis in cultured hepatocytes.

    PubMed

    Gómez-Lechón, María José; O'Connor, Enrique; Castell, José Vicente; Jover, Ramiro

    2002-02-01

    Apoptosis may be a major event in chemical-induced injury, and therefore the detection of apoptotic effects when developing new drugs is highly relevant in screening for pharmacotoxicological risk assessment. However, as apoptosis in vitro normally degenerates to secondary necrosis, it is possible that it is underestimated, unless sensitive and specific parameters are used. In this present study we have evaluated the usefulness of a set of markers associated with the pivotal steps in the execution phase of apoptosis, in order to detect apoptotic compounds in hepatocytes before significant necrosis takes place. The markers selected include several biochemical parameters (downregulation of the antiapoptotic bclX(L) gene, caspase-3 activation, and cytochrome C release from mitochondria), and flow cytometry determinations (analysis of the size of the nuclei, chromatin complexity, and DNA integrity). The effects of several well-known model apoptotic toxicants (galactosamine, tertiary-butyl-hydroperoxide, etoposide, campothecine, and curcumin) were analyzed in hepatocytes. The aim was to identify early markers of apoptosis using known inducers of apoptosis in hepatocytes, as this battery of markers is designed to identify compounds triggering apoptosis in hepatocytes prior to necrosis. Concentrations of the compounds, as low as possible in order to keep 90% of hepatocyte viability, were selected according to their intracellular lactate dehydrogenase (LDH) leakage, which is well known as an indicator of cell membrane integrity and cell viability. The results demonstrated that (1) the apoptotic effect of 4 out of 5 compounds could be detected in low concentrations of the drugs long before cell necrosis (tertiary-butyl-hydroperoxide-induced apoptosis was only detected at concentrations causing concomitant necrosis) and (2) among the markers evaluated, caspase 3 activation and nucleus and DNA analysis by flow cytometry were used to fulfil the compromise between reliability, sensitivity, and ease of performance, which are critical issues when screening for an apoptotic effect of newly developed drugs. PMID:11812934

  12. Chemical Compound Navigator: A Web-Based Chem-BLAST, Chemical Taxonomy-Based Search Engine for Browsing

    E-print Network

    Chemical Compound Navigator: A Web-Based Chem-BLAST, Chemical Taxonomy-Based Search Engine, query, and analyze chemical compounds has been developed and is illustrated by using the inhibitor data on HIV protease-inhibitor complexes. In this method, all chemical compounds are annotated in terms

  13. Chemicals from coal. Utilization of coal-derived phenolic compounds

    SciTech Connect

    Song, C.; Schobert, H.H.

    1999-07-01

    This article provides an overview for possible utilization of coal-derived phenolic compounds. Phenolic compounds are abundant in coal-derived liquids. Coal-derived phenolic compounds include phenol, cresol, catechol, methylcatechol, naphthol, and their derivatives. Liquids from coal liquefaction, pyrolysis, gasification, and carbonization are potential sources of phenolic chemicals, although certain processing and separation are needed. There are opportunities for coal-based phenolic chemicals, because there are existing industrial applications and potential new applications. Currently the petrochemical industry produces phenol in multi-step processes, and new research and development has resulted in a one-step process. Selective methylation of phenol can produce a precursor for aromatic engineering plastics. Catalytic oxidation of phenol has been commercialized recently for catechol production. There are potential new uses of phenol that could replace large-volume multi-step chemical processes that are based on benzene as the starting material. New chemical research on coal and coal-derived liquids can pave the way for their non-fuel uses for making chemicals and materials.

  14. Applications of swept-frequency acoustic interferometer for nonintrusive detection and identification of chemical warfare compounds

    SciTech Connect

    Sinha, D.N.; Springer, K.; Han, W.; Lizon, D.; Kogan, S.

    1997-12-01

    Swept-Frequency Acoustic Interferometry (SFAI) is a nonintrusive liquid characterization technique developed specifically for detecting and identifying chemical warfare (CW) compounds inside sealed munitions. The SFAI technique can rapidly (less than 20 seconds) and accurately determine sound speed and sound attenuation of a liquid inside a container over a wide frequency range (1 kHz-15 MHz). From the frequency-dependent sound attenuation measurement, liquid density is determined. These three physical properties are used to uniquely identify the CW compounds. In addition, various chemical relaxation processes in liquids and particle size distribution in emulsions can also be determined from the frequency-dependent attenuation measurement. The SFAI instrument is battery-operated and highly portable (< 6 lb.). The instrument has many potential application in industry ranging from sensitive detection (ppm level) of contamination to process control. The theory of the technique will be described and examples of several chemical industry applications will be presented.

  15. Antifungal Chemical Compounds Identified Using a C. elegans Pathogenicity Assay

    E-print Network

    Ausubel, Frederick M.

    of the main obstacles in current antifungal discovery. We show that Candida albicans, as well as other Candida. elegans intestinal track. Importantly, key components of Candida pathogenesis in mammals, such as filament formation, are also involved in nematode killing. We devised a Candida-mediated C. elegans assay that allows

  16. Deactivation of explosive/shock-sensitive chemical compounds

    SciTech Connect

    Uzzo, T.K.

    1994-12-31

    A change has occurred in how the environmental industry and scientific community view the safe handling and environmentally-protective disposal of explosive, shock-sensitive, and highly reactive chemical compounds. Until recently, the most common disposal technology for the removal of explosive chemicals such as dry picric acid or peroxidized ether compounds, was open air detonation--usually conducted by a state or local bomb squad. With the advent of more stringent environmental regulations and a heightened awareness of environmental liability and personal health and safety, uncontrolled detonation is no longer the preferred disposal option. The new standard for deactivation technologies emphasizes on-site stabilization followed by off-site incineration. Utilizing remotely-actuated equipment mounted in an explosion containment chamber, the explosive/shock-sensitive chemicals are deactivated on-site by physical or chemical means, and then disposed of off-site via incineration. Not only does this methodology minimize the risk of releasing chemical contaminants to air, water, or land, it also provides an increased level of personal protection through remote handling within an enclosed chamber, and allows for complete, documented thermal destruction at a permitted TSDF. This paper discusses available deactivation technologies and considers their practical application in the field. It also provides some insight into the High Hazard Remediation industry, and summarizes the types of high hazard materials typically encountered in laboratory and field remediation settings.

  17. Identification and deactivation of explosive/shock-sensitive chemical compounds

    SciTech Connect

    Uzzo, T.K.; Hoverkamp, F.J.

    1995-12-31

    A change has occurred in how the environmental industry and scientific community view the safe handling and environmentally-protective disposal of explosive, shock-sensitive, and highly reactive chemical compounds. Until recently, the most common disposal technology for the removal of explosive chemicals such as dry picric acid or peroxidized ether compounds, was open air detonation usually conducted by a state or local bomb squad. With the advent of more stringent environmental regulations and a heightened awareness of environmental liability and personal health and safety, uncontrolled detonation is no longer the preferred disposal option. The new standard for deactivation technologies emphasizes on-site stabilization followed by off-site incineration. Utilizing remotely-actuated equipment mounted in an explosion containment chamber, the explosive/shock-sensitive chemicals are deactivated on-site by physical or chemical means, and then disposed of off-site via incineration. Not only does this methodology minimize the risk of releasing chemical contaminants to air, water, or land, it also provides an increased level of personal protection through remote handling within an enclosed chamber, and allows for complete, documented thermal destruction at a permitted TSDF. This paper discusses available deactivation technologies and considers their practical application in the field. It also provides some insight into the High Hazard Remediation industry, and summarizes the types of high hazard materials typically encountered in laboratory and field remediation settings.

  18. Three Packets of Minerals of the Periodic Table of Chemical Elements and Chemical Compounds

    E-print Network

    Labushev, Mikhail M

    2013-01-01

    The concepts of alpha- and beta-packets of the periodic table of chemical elements and chemical compounds are defined. The first of the 47 minerals alpha-packets is composed. In it all minerals are arranged in increasing Iav index of proportionality of atomic weights of composing chemical elements, the same way as chemical elements are located in increasing atomic weights in the Periodic table. The packet includes 93 known minerals and two compounds - N2O5 and CO2 - being actually minerals. Beta-packet of oxides and hydroxides minerals includes 88 known minerals and five chemical compounds - N2O5, CO2, CO, SO3 and SO2. Two minerals of the packet have not been determined yet. Besides, beta-packet of minerals with sulfur, selenium or arsenic is composed, with one mineral not defined yet. The results of the calculations can be used for further development of the Periodic Table of Chemical Elements and Chemical Compounds and their properties investigation.

  19. Three Packets of Minerals of the Periodic Table of Chemical Elements and Chemical Compounds

    E-print Network

    Mikhail M. Labushev

    2013-03-20

    The concepts of alpha- and beta-packets of the periodic table of chemical elements and chemical compounds are defined. The first of the 47 minerals alpha-packets is composed. In it all minerals are arranged in increasing Iav index of proportionality of atomic weights of composing chemical elements, the same way as chemical elements are located in increasing atomic weights in the Periodic table. The packet includes 93 known minerals and two compounds - N2O5 and CO2 - being actually minerals. Beta-packet of oxides and hydroxides minerals includes 88 known minerals and five chemical compounds - N2O5, CO2, CO, SO3 and SO2. Two minerals of the packet have not been determined yet. Besides, beta-packet of minerals with sulfur, selenium or arsenic is composed, with one mineral not defined yet. The results of the calculations can be used for further development of the Periodic Table of Chemical Elements and Chemical Compounds and their properties investigation.

  20. Physical, chemical, and biological characteristics of compounds used in hydraulic fracturing.

    PubMed

    Stringfellow, William T; Domen, Jeremy K; Camarillo, Mary Kay; Sandelin, Whitney L; Borglin, Sharon

    2014-06-30

    Hydraulic fracturing (HF), a method to enhance oil and gas production, has become increasingly common throughout the U.S. As such, it is important to characterize the chemicals found in HF fluids to evaluate potential environmental fate, including fate in treatment systems, and human health impacts. Eighty-one common HF chemical additives were identified and categorized according to their functions. Physical and chemical characteristics of these additives were determined using publicly available chemical information databases. Fifty-five of the compounds are organic and twenty-seven of these are considered readily or inherently biodegradable. Seventeen chemicals have high theoretical chemical oxygen demand and are used in concentrations that present potential treatment challenges. Most of the HF chemicals evaluated are non-toxic or of low toxicity and only three are classified as Category 2 oral toxins according to standards in the Globally Harmonized System of Classification and Labeling of Chemicals; however, toxicity information was not located for thirty of the HF chemicals evaluated. Volatilization is not expected to be a significant exposure pathway for most HF chemicals. Gaps in toxicity and other chemical properties suggest deficiencies in the current state of knowledge, highlighting the need for further assessment to understand potential issues associated with HF chemicals in the environment. PMID:24853136

  1. Identifying Bioaccumulative Halogenated Organic Compounds Using a Nontargeted Analytical Approach: Seabirds as Sentinels

    PubMed Central

    Millow, Christopher J.; Mackintosh, Susan A.; Lewison, Rebecca L.; Dodder, Nathan G.; Hoh, Eunha

    2015-01-01

    Persistent organic pollutants (POPs) are typically monitored via targeted mass spectrometry, which potentially identifies only a fraction of the contaminants actually present in environmental samples. With new anthropogenic compounds continuously introduced to the environment, novel and proactive approaches that provide a comprehensive alternative to targeted methods are needed in order to more completely characterize the diversity of known and unknown compounds likely to cause adverse effects. Nontargeted mass spectrometry attempts to extensively screen for compounds, providing a feasible approach for identifying contaminants that warrant future monitoring. We employed a nontargeted analytical method using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/TOF-MS) to characterize halogenated organic compounds (HOCs) in California Black skimmer (Rynchops niger) eggs. Our study identified 111 HOCs; 84 of these compounds were regularly detected via targeted approaches, while 27 were classified as typically unmonitored or unknown. Typically unmonitored compounds of note in bird eggs included tris(4-chlorophenyl)methane (TCPM), tris(4-chlorophenyl)methanol (TCPMOH), triclosan, permethrin, heptachloro-1'-methyl-1,2'-bipyrrole (MBP), as well as four halogenated unknown compounds that could not be identified through database searching or the literature. The presence of these compounds in Black skimmer eggs suggests they are persistent, bioaccumulative, potentially biomagnifying, and maternally transferring. Our results highlight the utility and importance of employing nontargeted analytical tools to assess true contaminant burdens in organisms, as well as to demonstrate the value in using environmental sentinels to proactively identify novel contaminants. PMID:26020245

  2. Physical and Chemical Aspects of Stabilization of Compounds in Silk

    PubMed Central

    Pritchard, Eleanor M.; Dennis, Patrick B.; Omenetto, Fiorenzo; Naik, Rajesh R.; Kaplan, David L.

    2015-01-01

    The challenge of stabilization of small molecules and proteins has received considerable interest. The biological activity of small molecules can be lost as a consequence of chemical modifications, while protein activity may be lost due to chemical or structural degradation, such as a change in macromolecular conformation or aggregation. In these cases stabilization is required to preserve therapeutic and bioactivity efficacy and safety. In addition to use in therapeutic applications, strategies to stabilize small molecules and proteins also have applications in industrial processes, diagnostics, and consumer products like food and cosmetics. Traditionally, therapeutic drug formulation efforts have focused on maintaining stability during product preparation and storage. However, with growing interest in the fields of encapsulation, tissue engineering and controlled release drug delivery systems, new stabilization challenges are being addressed; the compounds or protein of interest must be stabilized during: (1) fabrication of the protein or small molecule loaded carrier, (2) device storage, and (3) for the duration of intended release needs in vitro or in vivo. We review common mechanisms of compound degradation for small molecules and proteins during biomaterial preparation (including tissue engineering scaffolds and drug delivery systems), storage and in vivo implantation. We also review the physical and chemical aspects of polymer-based stabilization approaches, with a particular focus on the stabilizing properties of silk fibroin biomaterials. PMID:22270942

  3. Chemical characterisation of semi-volatile and aerosol compounds from the photooxidation of toluene and NOx

    NASA Astrophysics Data System (ADS)

    White, Stephen J.; Jamie, Ian M.; Angove, Dennys E.

    2014-02-01

    The chemical composition of a gas phase and secondary organic aerosol (SOA) mixture from toluene photooxidation in NOx was determined. Aerosol from toluene photooxidation was generated in a smog chamber and was collected onto glass fibre filters along with those gas phase compounds which adhered to the filter. The filter bound organic material was extracted, derivatised with O-2,3,4,5,6-pentafluorobenzyl hydroxylamine (PFBHA) and N,O-bistrimethylsilyl-trifluoroacetamide (BSTFA), then analysed using gas chromatography-mass spectrometry (GC-MS). Compound identification was aided by the use of isotopically-labelled toluene. The effect of humidity on product formation was investigated by raising water vapour concentration in one experiment. Sixty compounds were identified, of which twenty had not been identified from toluene photooxidation previously. Small carboxylic acids and dicarbonyls provided the highest proportion of identifiable compounds by relative response. The use of water to extract the filter samples resulted in much higher relative responses for oxocarboxylic acids, such as glyoxylic acid and pyruvic acid, than has been observed in previous studies. The formation of levulinic acid was determined to be due to the reaction of water with aromatic photooxidation products in the gas phase or particle phase of the chamber experiment. Nuclear magnetic resonance (NMR) was used to determine the functional groups of water-extracted organic material, which indicated that the water-soluble components were comprised of compounds which contain similar functional groups, primarily alcohols and carboxylic acids.

  4. Electrolytic photodissociation of chemical compounds by iron oxide photochemical diodes

    DOEpatents

    Somorjai, Gabor A. (Berkeley, CA); Leygraf, Christofer H. (Berkeley, CA)

    1985-01-01

    Chemical compounds can be dissociated by contacting the same with a p/n type semi-conductor photochemical diode having visible light as its sole source of energy. The photochemical diode consists of low cost, readily available materials, specifically polycrystalline iron oxide doped with silicon in the case of the n-type semi-conductor electrode, and polycrystalline iron oxide doped with magnesium in the case of the p-type electrode. So long as the light source has an energy greater than 2.2 electron volts, no added energy source is needed to achieve dissociation.

  5. Electrolytic photodissociation of chemical compounds by iron oxide electrodes

    DOEpatents

    Somorjai, Gabor A. (Berkeley, CA); Leygraf, Christofer H. (Berkeley, CA)

    1984-01-01

    Chemical compounds can be dissociated by contacting the same with a p/n type semi-conductor diode having visible light as its sole source of energy. The diode consists of low cost, readily available materials, specifically polycrystalline iron oxide doped with silicon in the case of the n-type semi-conductor electrode, and polycrystalline iron oxide doped with magnesium in the case of the p-type electrode. So long as the light source has an energy greater than 2.2 electron volts, no added energy source is needed to achieve dissociation.

  6. Relationship between chemical structure and the occupational asthma hazard of low molecular weight organic compounds

    PubMed Central

    Jarvis, J; Seed, M; Elton, R; Sawyer, L; Agius, R

    2005-01-01

    Aims: To investigate quantitatively, relationships between chemical structure and reported occupational asthma hazard for low molecular weight (LMW) organic compounds; to develop and validate a model linking asthma hazard with chemical substructure; and to generate mechanistic hypotheses that might explain the relationships. Methods: A learning dataset used 78 LMW chemical asthmagens reported in the literature before 1995, and 301 control compounds with recognised occupational exposures and hazards other than respiratory sensitisation. The chemical structures of the asthmagens and control compounds were characterised by the presence of chemical substructure fragments. Odds ratios were calculated for these fragments to determine which were associated with a likelihood of being reported as an occupational asthmagen. Logistic regression modelling was used to identify the independent contribution of these substructures. A post-1995 set of 21 asthmagens and 77 controls were selected to externally validate the model. Results: Nitrogen or oxygen containing functional groups such as isocyanate, amine, acid anhydride, and carbonyl were associated with an occupational asthma hazard, particularly when the functional group was present twice or more in the same molecule. A logistic regression model using only statistically significant independent variables for occupational asthma hazard correctly assigned 90% of the model development set. The external validation showed a sensitivity of 86% and specificity of 99%. Conclusions: Although a wide variety of chemical structures are associated with occupational asthma, bifunctional reactivity is strongly associated with occupational asthma hazard across a range of chemical substructures. This suggests that chemical cross-linking is an important molecular mechanism leading to the development of occupational asthma. The logistic regression model is freely available on the internet and may offer a useful but inexpensive adjunct to the prediction of occupational asthma hazard. PMID:15778257

  7. High Throughput Screening Identifies a Novel Compound Protecting Cardiomyocytes from Doxorubicin-Induced Damage

    PubMed Central

    Gergely, Szabolcs; Heged?s, Csaba; Lakatos, Petra; Kovács, Katalin; Gáspár, Renáta; Csont, Tamás; Virág, László

    2015-01-01

    Antracyclines are effective antitumor agents. One of the most commonly used antracyclines is doxorubicin, which can be successfully used to treat a diverse spectrum of tumors. Application of these drugs is limited by their cardiotoxic effect, which is determined by a lifetime cumulative dose. We set out to identify by high throughput screening cardioprotective compounds protecting cardiomyocytes from doxorubicin-induced injury. Ten thousand compounds of ChemBridge's DIVERSet compound library were screened to identify compounds that can protect H9C2 rat cardiomyocytes against doxorubicin-induced cell death. The most effective compound proved protective in doxorubicin-treated primary rat cardiomyocytes and was further characterized to demonstrate that it significantly decreased doxorubicin-induced apoptotic and necrotic cell death and inhibited doxorubicin-induced activation of JNK MAP kinase without having considerable radical scavenging effect or interfering with the antitumor effect of doxorubicin. In fact the compound identified as 3-[2-(4-ethylphenyl)-2-oxoethyl]-1,2-dimethyl-1H-3,1-benzimidazol-3-ium bromide was toxic to all tumor cell lines tested even without doxorubicine treatment. This benzimidazole compound may lead, through further optimalization, to the development of a drug candidate protecting the heart from doxorubicin-induced injury. PMID:26137186

  8. Screening of Pharmacologically Active Small Molecule Compounds Identifies Antifungal Agents Against Candida Biofilms

    PubMed Central

    Watamoto, Takao; Egusa, Hiroshi; Sawase, Takashi; Yatani, Hirofumi

    2015-01-01

    Candida species have emerged as important and common opportunistic human pathogens, particularly in immunocompromised individuals. The current antifungal therapies either have toxic side effects or are insufficiently effect. The aim of this study is develop new small-molecule antifungal compounds by library screening methods using Candida albicans, and to evaluate their antifungal effects on Candida biofilms and cytotoxic effects on human cells. Wild-type C. albicans strain SC5314 was used in library screening. To identify antifungal compounds, we screened a small-molecule library of 1,280 pharmacologically active compounds (LOPAC1280TM) using an antifungal susceptibility test (AST). To investigate the antifungal effects of the hit compounds, ASTs were conducted using Candida strains in various growth modes, including biofilms. We tested the cytotoxicity of the hit compounds using human gingival fibroblast (hGF) cells to evaluate their clinical safety. Only 35 compounds were identified by screening, which inhibited the metabolic activity of C. albicans by >50%. Of these, 26 compounds had fungistatic effects and nine compounds had fungicidal effects on C. albicans. Five compounds, BAY11-7082, BAY11-7085, sanguinarine chloride hydrate, ellipticine and CV-3988, had strong fungicidal effects and could inhibit the metabolic activity of Candida biofilms. However, BAY11-7082, BAY11-7085, sanguinarine chloride hydrate and ellipticine were cytotoxic to hGF cells at low concentrations. CV-3988 showed no cytotoxicity at a fungicidal concentration. Four of the compounds identified, BAY11-7082, BAY11-7085, sanguinarine chloride hydrate and ellipticine, had toxic effects on Candida strains and hGF cells. In contrast, CV-3988 had fungicidal effects on Candida strains, but low cytotoxic effects on hGF cells. Therefore, this screening reveals agent, CV-3988 that was previously unknown to be antifungal agent, which could be a novel therapies for superficial mucosal candidiasis.

  9. 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

  10. International chemical identifier for reactions (RInChI)

    PubMed Central

    2013-01-01

    The IUPAC International Chemical Identifier (InChI) provides a method to generate a unique text descriptor of molecular structures. Building on this work, we report a process to generate a unique text descriptor for reactions, RInChI. By carefully selecting the information that is included and by ordering the data carefully, different scientists studying the same reaction should produce the same RInChI. If differences arise, these are most likely the minor layers of the InChI, and so may be readily handled. RInChI provides a concise description of the key data in a chemical reaction, and will help enable the rapid searching and analysis of reaction databases. PMID:24152584

  11. A Yeast/Drosophila Screen to Identify New Compounds Overcoming Frataxin Deficiency

    PubMed Central

    Seguin, Alexandra; Monnier, Véronique; Palandri, Amandine; Bihel, Frédéric; Rera, Michael; Schmitt, Martine; Camadro, Jean-Michel; Tricoire, Hervé; Lesuisse, Emmanuel

    2015-01-01

    Friedreich's ataxia (FA) is a rare neurodegenerative disease which is very debilitating for the patients who progressively lose their autonomy. The lack of efficient therapeutic treatment of the disease strongly argues for urgent need to search for new active compounds that may stop the progression of the disease or prevent the appearance of the symptoms when the genetic defect is diagnosed early enough. In the present study, we used a yeast strain with a deletion of the frataxin homologue gene as a model of FA cells in a primary screen of two chemical libraries, a fraction of the French National Chemical Library (5500 compounds) and the Prestwick collection (880 compounds). We ran a secondary screen on Drosophila melanogaster flies expressing reduced levels of frataxin during larval development. Half of the compounds selected in yeast appeared to be active in flies in this developmental paradigm, and one of the two compounds with highest activities in this assay partially rescued the heart dilatation phenotype resulting from heart specific depletion of frataxin. The unique complementarity of these two frataxin-deficient models, unicellular and multicellular, appears to be very efficient to select new compounds with improved selectivity, bringing significant perspectives towards improvements in FA therapy. PMID:26523199

  12. New Compound Sets Identified from High Throughput Phenotypic Screening Against Three Kinetoplastid Parasites: An Open Resource

    PubMed Central

    Peña, Imanol; Pilar Manzano, M.; Cantizani, Juan; Kessler, Albane; Alonso-Padilla, Julio; Bardera, Ana I.; Alvarez, Emilio; Colmenarejo, Gonzalo; Cotillo, Ignacio; Roquero, Irene; de Dios-Anton, Francisco; Barroso, Vanessa; Rodriguez, Ana; Gray, David W.; Navarro, Miguel; Kumar, Vinod; Sherstnev, Alexander; Drewry, David H.; Brown, James R.; Fiandor, Jose M.; Julio Martin, J.

    2015-01-01

    Using whole-cell phenotypic assays, the GlaxoSmithKline high-throughput screening (HTS) diversity set of 1.8 million compounds was screened against the three kinetoplastids most relevant to human disease, i.e. Leishmania donovani, Trypanosoma cruzi and Trypanosoma brucei. Secondary confirmatory and orthogonal intracellular anti-parasiticidal assays were conducted, and the potential for non-specific cytotoxicity determined. Hit compounds were chemically clustered and triaged for desirable physicochemical properties. The hypothetical biological target space covered by these diversity sets was investigated through bioinformatics methodologies. Consequently, three anti-kinetoplastid chemical boxes of ~200 compounds each were assembled. Functional analyses of these compounds suggest a wide array of potential modes of action against kinetoplastid kinases, proteases and cytochromes as well as potential host–pathogen targets. This is the first published parallel high throughput screening of a pharma compound collection against kinetoplastids. The compound sets are provided as an open resource for future lead discovery programs, and to address important research questions. PMID:25740547

  13. Identifying Sources of Volatile Organic Compounds and Aldehydes in a High Performance Building

    SciTech Connect

    Ortiz, Anna C.; Russell, Marion; Lee, Wen-Yee; Apte, Michael; Maddalena, Randy

    2010-09-20

    The developers of the Paharpur Business Center (PBC) and Software Technology Incubator Park in New Delhi, India offer an environmentally sustainable building with a strong emphasis on energy conservation, waste minimization and superior indoor air quality (IAQ). To achieve the IAQ goal, the building utilizes a series of air cleaning technologies for treating the air entering the building. These technologies include an initial water wash followed by ultraviolet light treatment and biolfiltration using a greenhouse located on the roof and numerous plants distributed throughout the building. Even with the extensive treatment of makeup air and room air in the PBC, a recent study found that the concentrations of common volatile organic compounds and aldehydes appear to rise incrementally as the air passes through the building from the supply to the exhaust. This finding highlights the need to consider the minimization of chemical sources in buildings in combination with the use of advanced air cleaning technologies when seeking to achieve superior IAQ. The goal of this project was to identify potential source materials for indoor chemicals in the PBC. Samples of building materials, including wood paneling (polished and unpolished), drywall, and plastic from a hydroponic drum that was part of the air cleaning system, were collected from the building for testing. All materials were collected from the PBC building and shipped to the Lawrence Berkeley National Laboratory (LBNL) for testing. The materials were pre-conditioned for two different time periods before measuring material and chemical specific emission factors for a range of VOCs and Aldehydes. Of the six materials tested, we found that the highest emitter of formaldehyde was new plywood paneling. Although polish and paint contribute to some VOC emissions, the main influence of the polish was in altering the capacity of the surface to accumulate formaldehyde. Neither the new nor aged polish contributed significantly to formaldehyde emissions. The VOC emission stream (excluding formaldehyde) was composed of up to 18 different chemicals and the total VOC emissions ranged in magnitude from 7 mu g/m2/h (old wood with old polish) to>500 mu g/m2/h (painted drywall). The formaldehyde emissions from drywall and old wood with either new or old polish were ~;;15 mu g/m2/h while the new wood material emitted>100 mu g/m2/h. However, when the projected surface area of each material in the building was considered, the new wood, old wood and painted drywall material all contributed substantially to the indoor formaldehyde loading while the coatings contributed primarily to the VOCs.

  14. Is the toxicity of pesticide mixtures on river biofilm accounted for solely by the major compounds identified?

    PubMed

    Kim Tiam, Sandra; Morin, Soizic; Bonet, Berta; Guasch, Helena; Feurtet-Mazel, Agnès; Eon, Mélissa; Gonzalez, Patrice; Mazzella, Nicolas

    2015-03-01

    Comparative effects of long-term exposure to Polar Organic Chemical Integrative Sampler (POCIS) extracts (PE) and to a reconstituted mixture based on the major compounds quantified in the PE were evaluated on river biofilm communities. The study aimed to characterize the effects of long-term and low-dose exposure to pesticides on natural biofilm communities and to evaluate if the effects due to PE exposure could be explained solely by the major compounds identified in the extracts. Biofilms from an uncontaminated site were exposed in artificial channels to realistic environmental concentrations using diluted PE, with the 12 major compounds quantified in the extracts (Mix) or with water not containing pesticides (Ctr). Significant differences between biofilms exposed to pesticides or not were observed with regard to diatom density, biomass (dry weight and ash-free dry mass), photosynthetic efficiency (?psII) and antioxidant enzyme activities. After 14 days of exposure to the different treatments, the observed trend towards a decrease of mean diatom cell biovolumes in samples exposed to pesticides was related to the control biofilms' higher relative abundance of large species like Cocconeis placentula or Amphora copulata and lower relative abundance of small species like Eolimna minima compared to the contaminated ones. Principal component analyses clearly separated contaminated (PE and Mix) from non-contaminated (Ctr) biofilms; on the contrary, the analyses did not reveal separation between biofilms exposed to PE or to the 12 major compounds identified in the extract. PMID:25077658

  15. Identifying inhibitory compounds in lignocellulosic biomass hydrolysates using an exometabolomics approach

    PubMed Central

    2014-01-01

    Background Inhibitors are formed that reduce the fermentation performance of fermenting yeast during the pretreatment process of lignocellulosic biomass. An exometabolomics approach was applied to systematically identify inhibitors in lignocellulosic biomass hydrolysates. Results We studied the composition and fermentability of 24 different biomass hydrolysates. To create diversity, the 24 hydrolysates were prepared from six different biomass types, namely sugar cane bagasse, corn stover, wheat straw, barley straw, willow wood chips and oak sawdust, and with four different pretreatment methods, i.e. dilute acid, mild alkaline, alkaline/peracetic acid and concentrated acid. Their composition and that of fermentation samples generated with these hydrolysates were analyzed with two GC-MS methods. Either ethyl acetate extraction or ethyl chloroformate derivatization was used before conducting GC-MS to prevent sugars are overloaded in the chromatograms, which obscure the detection of less abundant compounds. Using multivariate PLS-2CV and nPLS-2CV data analysis models, potential inhibitors were identified through establishing relationship between fermentability and composition of the hydrolysates. These identified compounds were tested for their effects on the growth of the model yeast, Saccharomyces. cerevisiae CEN.PK 113-7D, confirming that the majority of the identified compounds were indeed inhibitors. Conclusion Inhibitory compounds in lignocellulosic biomass hydrolysates were successfully identified using a non-targeted systematic approach: metabolomics. The identified inhibitors include both known ones, such as furfural, HMF and vanillin, and novel inhibitors, namely sorbic acid and phenylacetaldehyde. PMID:24655423

  16. Cyclodextrin-based chemical microsensors for Volatile Organic Compounds (VOCs)

    SciTech Connect

    Li, DeQuan

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). This project addressed the development of surface-acoustic-wave (SAW)-based chemical sensors for remote, real-time sensing in air, groundwater, and possibly soil, of chlorinated and aromatic hydrocarbons using innovative molecular self-assembly techniques. Our goal is parts per billion (ppb) sensitivity to specific aromatic and chlorinated hydrocarbons using cyclodextrin as the selective layer of a SAW-based mass sensor. We have demonstrated that SAW sensors can differentiate between compounds with similar composition, structure, and polarity. These efforts, however, can be enhanced by using sensor arrays and smart data processing systems. Secondly, ionic interactions provide a convenient way to fabricate thin films for sensor applications. The potential of these thin films for sensor applications is currently being evaluated. 3 figs.

  17. [Physical, chemical and bioactive compounds of tree tomato (Cyphomandra betacea)].

    PubMed

    Torres, Alexia

    2012-12-01

    Tree tomato (Cyphomandra betacea) is appreciated for its excellent nutritional qualities, being considered a good source of antioxidants compounds, calcium, phosphorus, potassium and iron, sugars, organic acids, pectins and flavonoids. In this study, were evaluated physical parameters (weight, size, compression strength and humidity) and chemical (degrees Brix, titratable acidity, pH, protein, dietary fiber, ash, minerals and their bioaccesibility, pectin, antioxidants compounds) of the fruit from the Aragua State, Venezuela, as a contribution to stimulate and diversify the consumption of the tree tomato. The characterization showed that the fruits were at the ripening stage for consumption (degrees Brix 10.51, pH 3.5, acidity 0.02 g/100ml and 4.32 Kgf/cm2 compression strength) gave a yield of 74% pulp. The analytical results of the ripped pulp showed a content of 30 Kcal/100 g, dietary fiber (4.10 g/100 g), and minerals such as phosphorous, calcium, magnesium, potassium and iron (331.32, 21.25, 21.18, 17.03 and 7.44 mg/100 g, respectively). Bioaccesibility values of 6.71 and 1.86% were reported for calcium and iron. The extracted pectin (1.00 g/100 g) was classified as high methoxyl with high degree of esterification. The antioxidant capacity of the ripped pulp (EC50 of 165.00 g/g DPPH and reducing power of 0.07 mmol Fe +2/100 g), could be attributed to the presence of ascorbic acid (23.32 mg/100 g), lycopene (1.22 mg/100 g), and phenolic compounds (1.39 mg GAE/g), anthocyanins (0.29 mg cyanidin/g) and tannins (0.40 mg catechin/100 g).The results obtained encourage the nutritional benefits and suggest applications as a functional ingredient in food product development. PMID:24020259

  18. IDENTIFYING COMPOUNDS USING SOURCE CID ON AN ORTHOGONAL ACCELERATION TIME-OF-FLIGHT MASS SPECTROMETER

    EPA Science Inventory

    Exact mass libraries of ESI and APCI mass spectra are not commercially available In-house libraries are dependent on CID parameters and are instrument specific. The ability to identify compounds without reliance on mass spectral libraries is therefore more crucial for liquid sam...

  19. A NEW MASS SPECTROMETRIC TECHNIQUE FOR IDENTIFYING TRACE-LEVEL ORGANIC COMPOUNDS IN COMPLEX MIXTURES

    EPA Science Inventory



    Most organic compounds are not found in mass spectral libraries and cannot be easily identified from low resolution mass spectra. Ion Composition Elucidation (ICE) utilizes selected ion recording with a double focusing mass spectrometer in a new way to determine exact mas...

  20. A chemical genetic approach identifies piperazine antipsychotics as promoters of CNS neurite growth on inhibitory substrates.

    PubMed

    Johnstone, Andrea L; Reierson, Gillian W; Smith, Robin P; Goldberg, Jeffrey L; Lemmon, Vance P; Bixby, John L

    2012-06-01

    Injury to the central nervous system (CNS) can result in lifelong loss of function due in part to the regenerative failure of CNS neurons. Inhibitory proteins derived from myelin and the astroglial scar are major barriers for the successful regeneration of injured CNS neurons. Previously, we described the identification of a novel compound, F05, which promotes neurite growth from neurons challenged with inhibitory substrates in vitro, and promotes axonal regeneration in vivo (Usher et al., 2010). To identify additional regeneration-promoting compounds, we used F05-induced gene expression profiles to query the Broad Institute Connectivity Map, a gene expression database of cells treated with >1300 compounds. Despite no shared chemical similarity, F05-induced changes in gene expression were remarkably similar to those seen with a group of piperazine phenothiazine antipsychotics (PhAPs). In contrast to antipsychotics of other structural classes, PhAPs promoted neurite growth of CNS neurons challenged with two different glial derived inhibitory substrates. Our pharmacological studies suggest a mechanism whereby PhAPs promote growth through antagonism of calmodulin signaling, independent of dopamine receptor antagonism. These findings shed light on mechanisms underlying neurite-inhibitory signaling, and suggest that clinically approved antipsychotic compounds may be repurposed for use in CNS injured patients. PMID:22561309

  1. High-Throughput Chemical Screens Identify Disulfiram as an Inhibitor of Human Glioblastoma Stem Cells

    PubMed Central

    Hothi, Parvinder; Martins, Timothy J.; Chen, LiPing; Deleyrolle, Loic; Yoon, Jae-Geun; Reynolds, Brent; Foltz, Greg

    2012-01-01

    Glioblastoma Multiforme (GBM) continues to have a poor patient prognosis despite optimal standard of care. Glioma stem cells (GSCs) have been implicated as the presumed cause of tumor recurrence and resistance to therapy. With this in mind, we screened a diverse chemical library of 2,000 compounds to identify therapeutic agents that inhibit GSC proliferation and therefore have the potential to extend patient survival. High-throughput screens (HTS) identified 78 compounds that repeatedly inhibited cellular proliferation, of which 47 are clinically approved for other indications and 31 are experimental drugs. Several compounds (such as digitoxin, deguelin, patulin and phenethyl caffeate) exhibited high cytotoxicity, with half maximal inhibitory concentrations (IC50) in the low nanomolar range. In particular, the FDA approved drug for the treatment of alcoholism, disulfiram (DSF), was significantly potent across multiple patient samples (IC50 of 31.1 nM). The activity of DSF was potentiated by copper (Cu), which markedly increased GSC death. DSF–Cu inhibited the chymotrypsin-like proteasomal activity in cultured GSCs, consistent with inactivation of the ubiquitin-proteasome pathway and the subsequent induction of tumor cell death. Given that DSF is a relatively non-toxic drug that can penetrate the blood-brain barrier, we suggest that DSF should be tested (as either a monotherapy or as an adjuvant) in pre-clinical models of human GBM. Data also support targeting of the ubiquitin-proteasome pathway as a therapeutic approach in the treatment of GBM. PMID:23165409

  2. High-throughput chemical screens identify disulfiram as an inhibitor of human glioblastoma stem cells.

    PubMed

    Hothi, Parvinder; Martins, Timothy J; Chen, Liping; Deleyrolle, Loic; Yoon, Jae-Geun; Reynolds, Brent; Foltz, Greg

    2012-10-01

    Glioblastoma Multiforme (GBM) continues to have a poor patient prognosis despite optimal standard of care. Glioma stem cells (GSCs) have been implicated as the presumed cause of tumor recurrence and resistance to therapy. With this in mind, we screened a diverse chemical library of 2,000 compounds to identify therapeutic agents that inhibit GSC proliferation and therefore have the potential to extend patient survival. High-throughput screens (HTS) identified 78 compounds that repeatedly inhibited cellular proliferation, of which 47 are clinically approved for other indications and 31 are experimental drugs. Several compounds (such as digitoxin, deguelin, patulin and phenethyl caffeate) exhibited high cytotoxicity, with half maximal inhibitory concentrations (IC50) in the low nanomolar range. In particular, the FDA approved drug for the treatment of alcoholism, disulfiram (DSF), was significantly potent across multiple patient samples (IC50 of 31.1 nM). The activity of DSF was potentiated by copper (Cu), which markedly increased GSC death. DSF-Cu inhibited the chymotrypsin-like proteasomal activity in cultured GSCs, consistent with inactivation of the ubiquitin-proteasome pathway and the subsequent induction of tumor cell death. Given that DSF is a relatively non-toxic drug that can penetrate the blood-brain barrier, we suggest that DSF should be tested (as either a monotherapy or as an adjuvant) in pre-clinical models of human GBM. Data also support targeting of the ubiquitin-proteasome pathway as a therapeutic approach in the treatment of GBM. PMID:23165409

  3. A high content screen identifies novel compounds that inhibit stress-induced TDP-43 cellular aggregation and associated cytotoxicity

    PubMed Central

    Zauur, Nava; Liu, Min; Concannon, John; Ebata, Atsushi; Wolozin, Benjamin; Glicksman, Marcie A.

    2014-01-01

    TDP-43 is an RNA binding protein found to accumulate in the cytoplasm of brain and spinal cord from patients affected with amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Nuclear TDP-43 protein regulates transcription through several mechanisms, and under stressed conditions it forms cytoplasmic aggregates that co-localize with stress granule (SG) proteins in cell culture. These granules are also found in the brain and spinal cord of patients affected with ALS and FTLD. The mechanism through which TDP-43 might contribute to neurodegenerative diseases is poorly understood. In order to investigate the pathophysiology of TDP-43 aggregation and to isolate potential therapeutic targets, we screened a chemical library of 75,000 compounds using high content analysis with PC12 cells that inducibly express human TDP-43 tagged with GFP. The screen identified 16 compounds that dose-dependently decreased the TDP-43 inclusions without significant cellular toxicity or changes in total TDP-43 expression levels. To validate the effect of the compounds, we tested compounds by Western Blot analysis and in a model that replicates some of the relevant disease phenotypes. The hits from this assay will be useful for elucidating regulation of TDP-43, stress granule response, and possible ALS therapeutics. PMID:24019256

  4. Next-generation NAMPT inhibitors identified by sequential high-throughput phenotypic chemical and functional genomic screens

    PubMed Central

    Matheny, Christina J.; Wei, Michael C.; Bassik, Michael C.; Donnelly, Alicia J.; Kampmann, Martin; Iwasaki, Masayuki; Piloto, Obdulio; Solow-Cordero, David E.; Bouley, Donna M.; Rau, Rachel; Brown, Patrick; McManus, Michael T.; Weissman, Jonathan S.; Cleary, Michael L.

    2013-01-01

    Summary Phenotypic high-throughput chemical screens allow for discovery of small molecules that modulate complex phenotypes and provide lead compounds for novel therapies; however, identification of the mechanistically relevant targets remains a major experimental challenge. We report the application of sequential unbiased high-throughput chemical and ultracomplex shRNA screens to identify a novel class of inhibitors that target nicotinamide phosphoribosyl transferase (NAMPT), a rate-limiting enzyme in the biosynthesis of nicotinamide adenine dinucleotide (NAD+), a crucial cofactor in many biochemical processes. The lead compound STF-118804 is a highly specific NAMPT inhibitor, improves survival in an orthotopic xenotransplant model of high-risk acute lymphoblastic leukemia, and targets leukemia stem cells. Tandem high-throughput screening using chemical and ultracomplex shRNA libraries, therefore, provides a rapid chemical genetics approach for seamless progression from small molecule lead identification to target discovery and validation. PMID:24183972

  5. The Periodic Table as a Part of the Periodic Table of Chemical Compounds

    E-print Network

    Labushev, Mikhail M

    2011-01-01

    The numbers of natural chemical elements, minerals, inorganic and organic chemical compounds are determined by 1, 2, 3 and 4-combinations of a set 95 and are respectively equal to 95, 4,465, 138,415 and 3,183,545. To explain these relations it is suggested the concept of information coefficient of proportionality as mathematical generalization of the proportionality coefficient for any set of positive numbers. It is suggested a hypothesis that the unimodal distributions of the sets of information coefficients of proportionality for atomic weights of chemical elements of minerals and chemical compounds correspond to unimodal distributions of the above sets for combination of 2, 3 and 4 atomic weights of 95 natural chemical elements. The expected values of symmetrized distributions of information coefficients of proportionality sets for atomic weights of minerals and chemical compounds are proposed to be used to define chemical compounds, like atomic weights define chemical elements. Variational series of the e...

  6. Machine learning of molecular electronic properties in chemical compound space

    NASA Astrophysics Data System (ADS)

    Montavon, Grégoire; Rupp, Matthias; Gobre, Vivekanand; Vazquez-Mayagoitia, Alvaro; Hansen, Katja; Tkatchenko, Alexandre; Müller, Klaus-Robert; Anatole von Lilienfeld, O.

    2013-09-01

    The combination of modern scientific computing with electronic structure theory can lead to an unprecedented amount of data amenable to intelligent data analysis for the identification of meaningful, novel and predictive structure-property relationships. Such relationships enable high-throughput screening for relevant properties in an exponentially growing pool of virtual compounds that are synthetically accessible. Here, we present a machine learning model, trained on a database of ab initio calculation results for thousands of organic molecules, that simultaneously predicts multiple electronic ground- and excited-state properties. The properties include atomization energy, polarizability, frontier orbital eigenvalues, ionization potential, electron affinity and excitation energies. The machine learning model is based on a deep multi-task artificial neural network, exploiting the underlying correlations between various molecular properties. The input is identical to ab initio methods, i.e. nuclear charges and Cartesian coordinates of all atoms. For small organic molecules, the accuracy of such a ‘quantum machine’ is similar, and sometimes superior, to modern quantum-chemical methods—at negligible computational cost.

  7. Estrogenicity profile and estrogenic compounds determined in river sediments by chemical analysis, ELISA and yeast assays.

    PubMed

    Viganò, Luigi; Benfenati, Emilio; van Cauwenberge, Anne; Eidem, Janne K; Erratico, Claudio; Goksøyr, Anders; Kloas, Werner; Maggioni, Silvia; Mandich, Alberta; Urbatzka, Ralph

    2008-10-01

    An effects-directed strategy was applied to bed sediments of a polluted tributary in order to isolate and identify the major estrogenic chemicals it discharges into the River Po, the principal Italian watercourse. Sediment extract was concentrated by solid phase extraction and then fractioned into 10 fractions by reversed phase high performance liquid chromatography (RP-HPLC). Estrogenic activity of whole extract and fractions were determined using a recombinant yeast assay containing the human estrogen receptor (YES). The 10 fractions and whole extract were analysed for target compounds, e.g. estrone (E1), 17beta-estradiol (E2), estriol (E3), 4-nonylphenol (NP), 4-tert-octylphenol (t-OP), bisphenol A (BPA), using both liquid chromatography-tandem mass spectrometry (LC-MS/MS) and non-competitive enzyme-linked immunosorbent assays (ELISA). The YES assay determined high estrogenic activity in whole sediment (15.6 ng/g EE2 equivalents), and positive results for fractions nr 1, 2, 6, 7 and 8. E1, E3 and NP were the main estrogenic chemicals, however, other unidentified compounds contributed to sediment estrogenicity, particularly for polar fractions nr 1 and 2. A GC-MS screening performed in scan mode identified other potential contributors such as phthalates (DBP, BBP), and OP isomers. A next sampling campaign extended to other tributaries and receiving stretches of the River Po confirmed E1, E3 and NP as major estrogenic chemicals potentially threatening other sites of the main river. In general, target compound ELISAs have been shown to be suitable tools for a rapid screening of wide areas or large numbers of environmental samples for estrogenic risk. The potential for interferences suggests however to use cautiously the concentration values obtained from some of the immunoassays. PMID:18799186

  8. Chemical compounds and toxicological assessments of drinking water stored in polyethylene terephthalate (PET)

    E-print Network

    Short, Daniel

    Chemical compounds and toxicological assessments of drinking water stored in polyethylene a positive list of substances that are authorized for use in plastic materials. Some compounds are subject and additives. Genotoxic and estrogenic activities in PET-bottled water have been reported. Chemical mixtures

  9. REVIEW OF VOLATILE ORGANIC COMPOUND SOURCE APPORTIONMENT BY CHEMICAL MASS BALANCE. (R826237)

    EPA Science Inventory

    The chemical mass balance (CMB) receptor model has apportioned volatile organic compounds (VOCs) in more than 20 urban areas, mostly in the United States. These applications differ in terms of the total fraction apportioned, the calculation method, the chemical compounds used ...

  10. In situ Analysis of Organic Compounds on Mars using Chemical Derivatization and Gas Chromatography Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Glavin, D. P.; Buch, A.; Cabane, M.; Coll, P.; Navarro-Gonzalez, R.; Mahaffy, P. R.

    2005-01-01

    One of the core science objectives of NASA's 2009 Mars Science Laboratory (MSL) mission is to determine the past or present habitability of Mars. The search for key organic compounds relevant to terrestrial life will be an important part of that assessment. We have developed a protocol for the analysis of amino acids and carboxylic acids in Mars analogue materials using gas chromatography mass spectrometry (GCMS). As shown, a variety of carboxylic acids were readily identified in soil collected from the Atacama Desert in Chile at part-per-billion levels by GCMS after extraction and chemical derivatization using the reagent N,N-tert.-butyl (dimethylsilyl) trifluoroacetamide (MTBSTFA). Several derivatized amino acids including glycine and alanine were also detected by GCMS in the Atacama soil at lower concentrations (chromatogram not shown). Lacking derivatization capability, the Viking pyrolysis GCMS instruments could not have detected amino acids and carboxylic acids, since these non-volatile compounds require chemical transformation into volatile species that are stable in a GC column. We are currently optimizing the chemical extraction and derivatization technique for in situ GCMS analysis on Mars. Laboratory results of analyses of Atacama Desert samples and other Mars analogue materials using this protocol will be presented.

  11. Historical trends in organochlorine compounds in river basins identified using sediment cores from reservoirs

    USGS Publications Warehouse

    Van Metre, P.C.; Callender, E.; Fuller, C.C.

    1997-01-01

    This study used chemical analyses of dated sediment cores from reservoirs to define historical trends in water quality in the influent river basins. This work applies techniques from paleolimnology to reservoirs, and in the process, highlights differences between sediment-core interpretations for reservoirs and natural lakes. Sediment cores were collected from six reservoirs in the central and southeastern United States, sectioned, and analyzed for 137Cs and organochlorine compounds. 137Cs analyses were used to demonstrate limited post-depositional mixing, to indicate sediment deposition dates, and to estimate sediment focusing factors. Relative lack of mixing, high sedimentation rates, and high focusing factors distinguish reservoir sediment cores from cores collected in natural lakes. Temporal trends in concentrations of PCBs, total DDT (DDT + DDD + DDE), and chlordane reflect historical use and regulation of these compounds and differences in land use between reservoir drainages. PCB and total DDT core burdens, normalized for sediment focusing, greatly exceed reported cumulative regional atmospheric fallout of PCBs and total DDT estimated using cores from peat hogs and natural lakes, indicating the dominance of fluvial inputs of both groups of compounds to the reservoirs.This study used chemical analyses of dated sediment cores from reservoirs to define historical trends in water quality in the influent river basins. This work applies techniques from paleolimnology to reservoirs, and in the process, highlights differences between sediment-core interpretations for reservoirs and natural lakes. Sediment cores were collected from six reservoirs in the central and southeastern United States, sectioned, and analyzed for 137Cs and organochlorine compounds. 137Cs analyses were used to demonstrate limited post-depositional mixing, to indicate sediment deposition dates, and to estimate sediment focusing factors. Relative lack of mixing, high sedimentation rates, and high focusing factors distinguish reservoir sediment cores from cores collected in natural lakes. Temporal trends in concentrations of PCBs, total DOT (DDT+DDD+DDE), and chlordane reflect historical use and regulation of these compounds and differences in land use between reservoir drainages. PCB and total DDT core burdens, normalized for sediment focusing, greatly exceed reported cumulative regional atmospheric fallout of PCBs and total DDT estimated using cores from peat bogs and natural lakes, indicating the dominance of fluvial inputs of both groups of compounds to the reservoirs.

  12. Environmental Fate of Organophosphorus Compounds Related to Chemical Weapons

    SciTech Connect

    Davisson, M L; Love, A H; Vance, A; Reynolds, J G

    2005-02-08

    Man-made organophosphorus compounds have been widely distributed throughout our environment as pesticides since their development during and after WWII. Many important studies have documented their relative persistence and toxicity. Development and use of some organophosphorus compounds as nerve agents gave rise to a separate but parallel effort to understand environmental persistence. In this latter case, the experiments have focused mainly on evaporation rates and first-order reaction kinetics. However, because organophosphorus compounds are easily polarized, the ionic content of a surrounding media directly factors into these reaction rates, but limited work in this regard has been done under environmentally relevant conditions. Furthermore, limited experiments investigating persistence of these agents on soil has resulted in widely varying degradation rates. Not surprisingly, no studies have investigated affinities of organophosphorus nerve agents to mineral or organic matter typically found in soil. As a result, we initiated laboratory experiments on dilute concentrations of nerve agent O-ethyl S-(2-diisopropylaminoethyl) methylphosphonothiolate (VX) to quantify persistence in simulated environmental aqueous conditions. A quantitative analytical method was developed for VX and its degradation products using High Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (HPLC-ESI-MS). VX hydrolysis rate is known to have a pH-dependency, however, the type of buffer and the relative proportion of different nucleophiles in solution significantly affect the overall rate and mechanism of degradation. For example, dissolved carbonate, a weak nucleophile dominating natural water, yielded pseudo-first order rate constants of {approx} 8 x 10{sup -3}/hr at pH 5 and 2 x 10{sup -2}/hr at pH 11. This small pH-dependent variation departs significantly from widely accepted rates at this pH range (4 x 10{sup -4}/hr to 8 x 10{sup -2}/hr) that were based on chloride and hydroxyl (strong nucleophile) dominated experimental solutions. Because of its overwhelming abundance in solution relative to hydroxyl ion, bicarbonate likely effectively competes in nucleophilic attack on phosphorus. The addition of natural dissolved organic matter at 100 mg/L in pH 7 bicarbonate buffered solution slowed VX hydrolysis rates {approx}2 times relative to controls, suggesting hydrophobic interaction. Adsorption experiments derived isotherms from batch aqueous experiments on montmorillonite clay, iron-oxyhydroxide goethite, and on amorphous silica. VX had moderate affinity for montmorillonite and amorphous silica, and very low affinity toward goethite. The addition of dissolved organic matter into solution enhanced VX adsorption to goethite, consistent with its high affinity for hydrophobic organic matter (log K{sub oc} = 2.52). Diisopropylaminoethylthiol (DESH), a hydrolysis product of VX showed equivalent adsorption to montmorillonite, and poor affinity to goethite and silica. However, hydrolysis products O-Ethylmethylphosphonic acid (EMPA) and methylphosphonic acid (MPA) strongly adsorbed on goethite, but not on montmorillonite or silica, suggesting a ligand-exchange mechanism. VX degraded rapidly when completely dried onto goethite followed by rehydration, consistent with an irreversible chemical adsorption mechanism.

  13. Histone markers identify the mode of action for compounds positive in the TK6 micronucleus assay.

    PubMed

    Cheung, Jennifer R; Dickinson, Donna A; Moss, Jocelyn; Schuler, Maik J; Spellman, Richard A; Heard, Pamela L

    2015-01-01

    The in vitro micronucleus assay with TK6 cells is frequently used as part of the genotoxicity testing battery for pharmaceuticals. Consequently, follow-up testing strategies are needed for positive compounds to determine their mode of action, which would then allow for deployment of appropriate in vivo follow-up strategies. We have chosen 3 micronucleus positive compounds, the clastogen etoposide, the aneugen noscapine and the cytotoxicant tunicamycin to evaluate different approaches to determine their aneugenic or clastogenic properties. Each of the three compounds were evaluated following 4 and 24h of continuous treatment by flow cytometry for micronucleus induction, the aneugenicity markers phosphorylated-histone 3 (p-H3) and polyploidy, the clastogenicity marker ?H2AX and the apoptosis marker cleaved caspase 3. They were further evaluated by Western blot for mono-ubiquitinated and ?H2AX. Results show that the clastogen etoposide produced a dose related increase in ?H2AX and mono-ubiquitinated H2AX and a dose related decrease in p-H3 positive mitotic cells. Conversely, the aneugen produced increases in p-H3 and polyploidy with no significant increases seen in mono-ubiquitinated H2AX or ?H2AX. Lastly, the cytotoxicant tunicamycin induced neither an increase in p-H3 nor ?H2AX. All three compounds produced dose-related increases in cleaved caspase 3. The results from this study provide evidence that adding clastogenicity and aneugenicity markers to the in vitro micronucleus assay in TK6 cells could help to identify the mode of action of positive compounds. The combination of endpoints suggested here needs to be further evaluated by a broader set of test compounds. PMID:25726170

  14. Microwave spectra of some sulfur and nitrogen compounds. [for chemical analysis

    NASA Technical Reports Server (NTRS)

    White, W. F.

    1974-01-01

    A computer-controlled microwave spectrometer was used to catalog reference spectra for chemical analysis. The apparatus, software, and experimental procedures are described. Tables of absorption frequencies, peak absorption coefficients, and integrated intensities are included for 13 sulfur compounds, 14 nitrogen compounds, and 1 compound containing both sulfur and nitrogen. The frequency range covered was 26,500 to 40,000 MHz for most compounds and 18,000 to 40,000 MHz for some.

  15. Parallel RNAi and compound screens identify the PDK1 pathway as a target for tamoxifen sensitization.

    PubMed

    Iorns, Elizabeth; Lord, Christopher J; Ashworth, Alan

    2009-01-01

    Tamoxifen is the most commonly used drug to treat breast cancer and acts by blocking ERalpha (oestrogen receptor alpha) signalling. Although highly effective, its usefulness is limited by the development of resistance. Given this, strategies that limit resistance by sensitizing cells to tamoxifen may be of use in the clinic. To gain insight into how this might be achieved, we used chemical and genetic screens to identify targets and small-molecule inhibitors that cause tamoxifen sensitization. A high-throughput genetic screen, using an RNA interference library targeting 779 kinases and related proteins, identified the PDK1 (phosphoinositide-dependent kinase 1) signalling pathway as a strong determinant of sensitivity to multiple ERalpha antagonists, including tamoxifen. A chemical screen using existing drugs and known kinase inhibitors also identified inhibitors of the PDK1 pathway, including triciribine and tetrandrine. Aside from identifying novel agents and targets for tamoxifen sensitization, this approach also provides evidence that performing chemical and genetic screens in parallel may be useful. PMID:18976239

  16. A Chemical Screening Approach to Identify Novel Key Mediators of Erythroid Enucleation

    PubMed Central

    Wölwer, Christina B.; Pase, Luke B.; Pearson, Helen B.; Gödde, Nathan J.; Lackovic, Kurt; Huang, David C. S.; Russell, Sarah M.; Humbert, Patrick O.

    2015-01-01

    Erythroid enucleation is critical for terminal differentiation of red blood cells, and involves extrusion of the nucleus by orthochromatic erythroblasts to produce reticulocytes. Due to the difficulty of synchronizing erythroblasts, the molecular mechanisms underlying the enucleation process remain poorly understood. To elucidate the cellular program governing enucleation, we utilized a novel chemical screening approach whereby orthochromatic cells primed for enucleation were enriched ex vivo and subjected to a functional drug screen using a 324 compound library consisting of structurally diverse, medicinally active and cell permeable drugs. Using this approach, we have confirmed the role of HDACs, proteasomal regulators and MAPK in erythroid enucleation and introduce a new role for Cyclin-dependent kinases, in particular CDK9, in this process. Importantly, we demonstrate that when coupled with imaging analysis, this approach provides a powerful means to identify and characterize rate limiting steps involved in the erythroid enucleation process. PMID:26569102

  17. Process for preparing a chemical compound enriched in isotope content. [nitrogen 15-enriched nitric acid

    DOEpatents

    Michaels, E.D.

    1981-02-25

    A process to prepare a chemical enriched in isotope content includes: a chemical exchange reaction between a first and second compound which yields an isotopically enriched first compound and an isotopically depleted second compound; the removal of a portion of the first compound as product and the removal of a portion of the second compound as spent material; the conversion of the remainder of the first compound to the second compound for reflux at the product end of the chemical exchange reaction region; the conversion of the remainder of the second compound to the first compound for reflux at the spent material end of the chemical exchange region; and the cycling of the additional chemicals produced by one conversion reaction to the other conversion reaction, for consumption therein. One of the conversion reactions is an oxidation reaction, and the energy that it yields is used to drive the other conversion reaction, a reduction. The reduction reaction is carried out in a solid polymer electrolyte electrolytic reactor. The overall process is energy efficient and yields no waste by-products. A particular embodiment of the process in the production of nitrogen-15-enriched nitric acid.

  18. Exposure levels for chemical threat compounds: information to facilitate chemical incident response.

    PubMed

    Hauschild, Veronique D; Watson, Annetta

    2013-01-01

    Although not widely known, a robust set of peer-reviewed public health and occupational exposure levels presently exist for key chemical warfare agents (CWAs) and certain acutely toxic industrial chemicals (TICs) identified as terrorist attack threats. Familiarity with these CWA and TIC exposure levels and their historic applications has facilitated emergency management decision-making by public and environmental health decision-makers. Specifically, multiple air, soil, and water exposure levels for CWAs and TICs summarized here have been extensively peer-reviewed and published; many have been recognized and are in use by federal and state health agencies as criteria for hazard zone prediction and assessment, occupational safety, and "how clean is clean enough" decisions. The key, however, is to know which criteria are most appropriate for specific decisions. While public safety is critical, high levels of concern often associated with perceived or actual proximity to extremely toxic chemical agents could result in overly cautious decisions that generate excessive delays, expenditure of scarce resources, and technological difficulties. Rapid selection of the most appropriate chemical exposure criteria is recommended to avoid such problems and expedite all phases of chemical incident response and recovery. PMID:24340456

  19. Predicting Physical-Chemical Properties of Compounds from Molecular Structures by Recursive Neural Networks

    E-print Network

    Sperduti, Alessandro

    Predicting Physical-Chemical Properties of Compounds from Molecular Structures by Recursive Neural of a recently developed neural network for structures applied to the prediction of physical chemical properties. INTRODUCTION To predict the physical-chemical properties of com- pounds, starting from the molecular structure

  20. A cell-based fascin bioassay identifies compounds with potential anti-metastasis or cognition-enhancing functions

    PubMed Central

    Kraft, Robert; Kahn, Allon; Medina-Franco, José L.; Orlowski, Mikayla L.; Baynes, Cayla; López-Vallejo, Fabian; Barnard, Kobus; Maggiora, Gerald M.; Restifo, Linda L.

    2013-01-01

    SUMMARY The actin-bundling protein fascin is a key mediator of tumor invasion and metastasis and its activity drives filopodia formation, cell-shape changes and cell migration. Small-molecule inhibitors of fascin block tumor metastasis in animal models. Conversely, fascin deficiency might underlie the pathogenesis of some developmental brain disorders. To identify fascin-pathway modulators we devised a cell-based assay for fascin function and used it in a bidirectional drug screen. The screen utilized cultured fascin-deficient mutant Drosophila neurons, whose neurite arbors manifest the ‘filagree’ phenotype. Taking a repurposing approach, we screened a library of 1040 known compounds, many of them FDA-approved drugs, for filagree modifiers. Based on scaffold distribution, molecular-fingerprint similarities, and chemical-space distribution, this library has high structural diversity, supporting its utility as a screening tool. We identified 34 fascin-pathway blockers (with potential anti-metastasis activity) and 48 fascin-pathway enhancers (with potential cognitive-enhancer activity). The structural diversity of the active compounds suggests multiple molecular targets. Comparisons of active and inactive compounds provided preliminary structure-activity relationship information. The screen also revealed diverse neurotoxic effects of other drugs, notably the ‘beads-on-a-string’ defect, which is induced solely by statins. Statin-induced neurotoxicity is enhanced by fascin deficiency. In summary, we provide evidence that primary neuron culture using a genetic model organism can be valuable for early-stage drug discovery and developmental neurotoxicity testing. Furthermore, we propose that, given an appropriate assay for target-pathway function, bidirectional screening for brain-development disorders and invasive cancers represents an efficient, multipurpose strategy for drug discovery. PMID:22917928

  1. Identifying and designing chemicals with minimal acute aquatic toxicity

    PubMed Central

    Kostal, Jakub; Voutchkova-Kostal, Adelina; Anastas, Paul T.; Zimmerman, Julie Beth

    2015-01-01

    Industrial ecology has revolutionized our understanding of material stocks and flows in our economy and society. For this important discipline to have even deeper impact, we must understand the inherent nature of these materials in terms of human health and the environment. This paper focuses on methods to design synthetic chemicals to reduce their intrinsic ability to cause adverse consequence to the biosphere. Advances in the fields of computational chemistry and molecular toxicology in recent decades allow the development of predictive models that inform the design of molecules with reduced potential to be toxic to humans or the environment. The approach presented herein builds on the important work in quantitative structure–activity relationships by linking toxicological and chemical mechanistic insights to the identification of critical physical–chemical properties needed to be modified. This in silico approach yields design guidelines using boundary values for physiochemical properties. Acute aquatic toxicity serves as a model endpoint in this study. Defining value ranges for properties related to bioavailability and reactivity eliminates 99% of the chemicals in the highest concern for acute aquatic toxicity category. This approach and its future implementations are expected to yield very powerful tools for life cycle assessment practitioners and molecular designers that allow rapid assessment of multiple environmental and human health endpoints and inform modifications to minimize hazard. PMID:24639521

  2. Identifying and designing chemicals with minimal acute aquatic toxicity.

    PubMed

    Kostal, Jakub; Voutchkova-Kostal, Adelina; Anastas, Paul T; Zimmerman, Julie Beth

    2015-05-19

    Industrial ecology has revolutionized our understanding of material stocks and flows in our economy and society. For this important discipline to have even deeper impact, we must understand the inherent nature of these materials in terms of human health and the environment. This paper focuses on methods to design synthetic chemicals to reduce their intrinsic ability to cause adverse consequence to the biosphere. Advances in the fields of computational chemistry and molecular toxicology in recent decades allow the development of predictive models that inform the design of molecules with reduced potential to be toxic to humans or the environment. The approach presented herein builds on the important work in quantitative structure-activity relationships by linking toxicological and chemical mechanistic insights to the identification of critical physical-chemical properties needed to be modified. This in silico approach yields design guidelines using boundary values for physiochemical properties. Acute aquatic toxicity serves as a model endpoint in this study. Defining value ranges for properties related to bioavailability and reactivity eliminates 99% of the chemicals in the highest concern for acute aquatic toxicity category. This approach and its future implementations are expected to yield very powerful tools for life cycle assessment practitioners and molecular designers that allow rapid assessment of multiple environmental and human health endpoints and inform modifications to minimize hazard. PMID:24639521

  3. The Use of Functional Chemical-Protein Associations to Identify Multi-Pathway Renoprotectants

    PubMed Central

    Xu, Jia; Meng, Kexin; Zhang, Rui; Yang, He; Liao, Chang; Zhu, Wenliang; Jiao, Jundong

    2014-01-01

    Typically, most nephropathies can be categorized as complex human diseases in which the cumulative effect of multiple minor genes, combined with environmental and lifestyle factors, determines the disease phenotype. Thus, multi-target drugs would be more likely to facilitate comprehensive renoprotection than single-target agents. In this study, functional chemical-protein association analysis was performed to retrieve multi-target drugs of high pathway wideness from the STITCH 3.1 database. Pathway wideness of a drug evaluated the efficiency of regulation of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in quantity. We identified nine experimentally validated renoprotectants that exerted remarkable impact on KEGG pathways by targeting a limited number of proteins. We selected curcumin as an illustrative compound to display the advantage of multi-pathway drugs on renoprotection. We compared curcumin with hemin, an agonist of heme oxygenase-1 (HO-1), which significantly affects only one KEGG pathway, porphyrin and chlorophyll metabolism (adjusted p?=?1.5×10?5). At the same concentration (10 µM), both curcumin and hemin equivalently mitigated oxidative stress in H2O2-treated glomerular mesangial cells. The benefit of using hemin was derived from its agonistic effect on HO-1, providing relief from oxidative stress. Selective inhibition of HO-1 completely blocked the action of hemin but not that of curcumin, suggesting simultaneous multi-pathway intervention by curcumin. Curcumin also increased cellular autophagy levels, enhancing its protective effect; however, hemin had no effects. Based on the fact that the dysregulation of multiple pathways is implicated in the etiology of complex diseases, we proposed a feasible method for identifying multi-pathway drugs from compounds with validated targets. Our efforts will help identify multi-pathway agents capable of providing comprehensive protection against renal injuries. PMID:24830678

  4. [Assessment of the relationship of properties of chemical compounds and their toxicity to a unified hygienic standardization for chemicals].

    PubMed

    Trushkov, V F; Perminov, K A; Sapozhnikova, V V; Ignatova, O L

    2013-01-01

    The connection of thermodynamic properties and parameters of toxicity of chemical substances was determined. Obtained data are used for the evaluation of toxicity and hygienic rate setting of chemical compounds. The relationship between enthalpy and toxicity of chemical compounds has been established. Orthogonal planning of the experiment was carried out in the course of the investigations. Equation of unified hygienic rate setting in combined, complex, conjunct influence on the organism is presented. Prospects of determination of toxicity and methodology of unified hygienic rate setting in combined, complex, conjunct influence on the organism are presented PMID:24003710

  5. Compounds identified in-flight by ROSETTA-COSIMA before the comet encounter

    NASA Astrophysics Data System (ADS)

    Hilchenbach, M.; Fischer, H.; Krüger, H.; Thirkell, L.; Rynö, J.

    2013-09-01

    Secondary ion mass spectrometry (SIMS) is a laboratory surface analyzing technique and, with the COSIMA instrument onboard ROSETTA, it will be applied for the first time to in-situ measurements of cometary grains, once ROSETTA encounters its target comet, 67P/Churyumov-Gerasimenko, in the September 2014. The COmetary Secondary Ion Mass analyzer (COSIMA) onboard ROSETTA will expose metal targets, collect cometary dust grains in the inner coma and analyze these with an optical microscope as well as secondary ion mass spectrometry [1]. The COSIMA instrument has been operated in-flight for commissioning in the first months after launch in March 2004 and on a regular basis during the passive and active spacecraft check-out time intervals up to ROSETTA hibernation from June 2011 onwards. The secondary ion mass spectra background and /or contamination level of the COSIMA metal targets has been identified prior to launch and these had been selected accordingly to avoid masking of single elements or compounds by carrying different metal targets for cometary grain collection. The main compounds identified in-flight are silicon polymers and hydrocarbons. We will discuss the surface analysis results with COSIMA, carried out far off any comet or asteroid in interplanetary space, their time evolution and their potential sources within ROSETTA.

  6. A Chemical Mutagenesis Screen Identifies Mouse Models with ERG Defects.

    PubMed

    Charette, Jeremy R; Samuels, Ivy S; Yu, Minzhong; Stone, Lisa; Hicks, Wanda; Shi, Lan Ying; Krebs, Mark P; Naggert, Jürgen K; Nishina, Patsy M; Peachey, Neal S

    2016-01-01

    Mouse models provide important resources for many areas of vision research, pertaining to retinal development, retinal function and retinal disease. The Translational Vision Research Models (TVRM) program uses chemical mutagenesis to generate new mouse models for vision research. In this chapter, we report the identification of mouse models for Grm1, Grk1 and Lrit3. Each of these is characterized by a primary defect in the electroretinogram. All are available without restriction to the research community. PMID:26427409

  7. Identifying chemicals from their Raman spectra using minimum description length

    NASA Astrophysics Data System (ADS)

    Palkki, Ryan D.; Lanterman, Aaron D.

    2010-04-01

    Raman spectroscopy has been a powerful means of chemical identification in a variety of fields, partly because of its non-contact nature and the speed at which measurements can be taken. Given a library of known Raman spectra, a common detection approach is to first estimate the relative amount of each chemical present, and then compare the estimated mixing coefficients to an ad hoc threshold. We present a more rigorous detection scheme by formulating the problem as one of Multiple Hypothesis Detection (MHD) and using the maximum a posteriori (MAP) decision rule to minimize the probability of classification error. The probability that a specific target chemical is present is estimated by summing the estimated probabilities of all the hypotheses containing it. Alternatively, since we do not typically have reasonable priors for the hypotheses, it is perhaps preferable to interpret the result as an abstract score corresponding to the Minimum Description Length (MDL) approach. The resulting detection performance of this approach is compared to that of several other classification algorithms.

  8. Reactivity of target compounds for chemical coal desulfurization. Technical report, 1 December 1993--28 February 1994

    SciTech Connect

    Buchanan, D.H.; Amin, M.; Cunningham, R.; Galyen, J.

    1994-06-01

    This project seeks to identify representative organosulfur compounds which are removed by coal desulfurization reactions. Demineralized coals from the Illinois Basin Coal Sample Program are solvent extracted and the extracts fractionated to separate and concentrate organosulfur compounds for analysis by Gas Chromatography/Mass Spectroscopy. After sulfur compounds are characterized, the parent extracts will be subjected to reactions previously shown to reduce the organic sulfur content of Illinois coals, fractionated and again analyzed for organosulfur content to determine which compounds reacted during the chemical treatment. The original coal will be subjected to chemical desulfurization, extraction, fractionation and analysis in order to correlate changes in organic sulfur content of the coal with reactions of specific sulfur compounds. These compounds can thus be reliably considered as target molecules for the next generation of desulfurization processes. During this quarter, work continued on developing efficient methods to isolate and analyze sulfur-rich coal extract fractions by GC/MS. Since only relatively non-polar compounds can be analyzed, pyridine extracts must be fractionated. Direct extraction of several coals with toluene is quicker but did not give as much toluene soluble material as fractionation of pyridine extracts and is thus not suitable for preparation of representative analytical samples. The authors observe that most IBC sample program coals contain elemental sulfur due to oxidation of pyrite. There is less elemental sulfur in IBC-101 than in other Herrin coals. This coal was washed in a preparation plant to reduce pyrite concentration. Since elemental sulfur slowly reacts to produce organosulfur compounds in coal during storage or handling, this suggests that early removal of pyrite can reduce formation of these hard to remove compounds.

  9. Apatite Formation: Why It May Not Work as Planned, and How to Conclusively Identify Apatite Compounds

    PubMed Central

    2013-01-01

    Calcium phosphate apatites are inorganic compounds encountered in many different mineralized tissues. Bone mineral, for example, is constituted of nanocrystalline nonstoichiometric apatite, and the production of “analogs” through a variety of methods is frequently reported. In another context, the ability of solid surfaces to favor the nucleation and growth of “bone-like” apatite upon immersion in supersaturated fluids such as SFB is commonly used as one evaluation index of the “bioactivity” of such surfaces. Yet, the compounds or deposits obtained are not always thoroughly characterized, and their apatitic nature is sometimes not firmly assessed by appropriate physicochemical analyses. Of particular importance are the “actual” conditions in which the precipitation takes place. The precipitation of a white solid does not automatically indicate the formation of a “bone-like carbonate apatite layer” as is sometimes too hastily concluded: “all that glitters is not gold.” The identification of an apatite phase should be carefully demonstrated by appropriate characterization, preferably using complementary techniques. This review considers the fundamentals of calcium phosphate apatite characterization discussing several techniques: electron microscopy/EDX, XRD, FTIR/Raman spectroscopies, chemical analyses, and solid state NMR. It also underlines frequent problems that should be kept in mind when making “bone-like apatites.” PMID:23984373

  10. Chemical properties and methods of analysis of refractory compounds

    NASA Technical Reports Server (NTRS)

    Samsonov, G. V. (editor); Frantsevich, I. N. (editor); Yeremenko, V. N. (editor); Nazarchuk, T. N. (editor); Popova, O. I. (editor)

    1978-01-01

    Reactions involving refractory metals and the alloys based on them are discussed. Chemical, electrochemical, photometric, spectrophotometric, and X-ray analysis are among the methods described for analyzing the results of the reactions and for determining the chemical properties of these materials.

  11. LOW VOLATILE ORGANIC COMPOUND (VOC) CHEMICAL AGENT RESISTANT COATING (CARC)

    EPA Science Inventory

    Chemical warfare causes many problems on the battlefield, among which is decontamination of exposed equipment. Because of this threat, the US Army ahs required the use of a Chemical Agent Resistant Coating (CARC) system on its equipment, beginning in FY 85. The equipment covere...

  12. ESTIMATION OF PHYSICAL PROPERTIES AND CHEMICAL REACTIVITY PARAMETERS OF ORGANIC COMPOUNDS

    EPA Science Inventory

    The computer program SPARC (Sparc Performs Automated Reasoning in Chemistry)has been under development for several years to estimate physical properties and chemical reactivity parameters of organic compounds strictly from molecular structure. SPARC uses computational algorithms ...

  13. Cyanobacterium sp. host cell and vector for production of chemical compounds in cyanobacterial cultures

    DOEpatents

    Piven, Irina; Friedrich, Alexandra; Duhring, Ulf; Uliczka, Frank; Baier, Kerstin; Inaba, Masami; Shi, Tuo; Wang, Kui; Enke, Heike; Kramer, Dan

    2014-09-30

    A cyanobacterial host cell, Cyanobacterium sp., that harbors at least one recombinant gene for the production of a chemical compounds is provided, as well as vectors derived from an endogenous plasmid isolated from the cell.

  14. PREDICTION OF CHEMICAL REACTIVITY PARAMETERS AND PHYSICAL PROPERTIES OF ORGANIC COMPOUNDS FROM MOLECULAR STRUCTURE USING SPARC

    EPA Science Inventory

    The computer program SPARC (SPARC Performs Automated Reasoning in Chemistry) has been under development for several years to estimate physical properties and chemical reactivity parameters of organic compounds strictly from molecular structure. SPARC uses computational algorithms...

  15. Compound

    NASA Astrophysics Data System (ADS)

    Suzumura, Akitoshi; Watanabe, Masaki; Nagasako, Naoyuki; Asahi, Ryoji

    2014-06-01

    Recently, Cu-based chalcogenides such as Cu3SbSe4, Cu2Se, and Cu2SnSe3 have attracted much attention because of their high thermoelectric performance and their common feature of very low thermal conductivity. However, for practical use, materials without toxic elements such as selenium are preferable. In this paper, we report Se-free Cu3SbS4 thermoelectric material and improvement of its figure of merit ( ZT) by chemical substitutions. Substitutions of 3 at.% Ag for Cu and 2 at.% Ge for Sb lead to significant reductions in the thermal conductivity by 37% and 22%, respectively. These substitutions do not sacrifice the power factor, thus resulting in enhancement of the ZT value. The sensitivity of the thermal conductivity to chemical substitutions in these compounds is discussed in terms of the calculated phonon dispersion and previously proposed models for Cu-based chalcogenides. To improve the power factor, we optimize the hole carrier concentration by substitution of Ge for Sb, achieving a power factor of 16 ?W/cm K2 at 573 K, which is better than the best reported for Se-based Cu3SbSe4 compounds.

  16. Inhibition of the compound action potentials of frog sciatic nerves by aroma oil compounds having various chemical structures

    PubMed Central

    Ohtsubo, Sena; Fujita, Tsugumi; Matsushita, Akitomo; Kumamoto, Eiichi

    2015-01-01

    Plant-derived chemicals including aroma oil compounds have an ability to inhibit nerve conduction and modulate transient receptor potential (TRP) channels. Although applying aroma oils to the skin produces a local anesthetic effect, this has not been yet examined throughly. The aim of the present study was to know how nerve conduction inhibitions by aroma oil compounds are related to their chemical structures and whether these activities are mediated by TRP activation. Compound action potentials (CAPs) were recorded from the frog sciatic nerve by using the air-gap method. Citral (aldehyde), which activates various types of TRP channels, attenuated the peak amplitude of CAP with the half-maximal inhibitory concentration (IC50) value of 0.46 mmol/L. Another aldehyde (citronellal), alcohol (citronellol, geraniol, (±)-linalool, (?)-linalool, (+)-borneol, (?)-borneol, ?-terpineol), ester (geranyl acetate, linalyl acetate, bornyl acetate), and oxide (rose oxide) compounds also reduced CAP peak amplitudes (IC50: 0.50, 0.35, 0.53, 1.7, 2.0, 1.5, 2.3, 2.7, 0.51, 0.71, 0.44, and 2.6 mmol/L, respectively). On the other hand, the amplitudes were reduced by a small extent by hydrocarbons (myrcene and p-cymene) and ketone (camphor) at high concentrations (2–5 mmol/L). The activities of citral and other TRP agonists ((+)-borneol and camphor) were resistant to TRP antagonist ruthenium red. An efficacy sequence for the CAP inhibitions was generally aldehydes ? esters ? alcohols > oxides >> hydrocarbons. The CAP inhibition by the aroma oil compound was not related to its octanol–water partition coefficient. It is suggested that aroma oil compounds inhibit nerve conduction in a manner specific to their chemical structures without TRP activation. PMID:26038703

  17. Quantum chemical calculations for polymers and organic compounds

    NASA Technical Reports Server (NTRS)

    Lopez, J.; Yang, C.

    1982-01-01

    The relativistic effects of the orbiting electrons on a model compound were calculated. The computational method used was based on 'Modified Neglect of Differential Overlap' (MNDO). The compound tetracyanoplatinate was used since empirical measurement and calculations along "classical" lines had yielded many known properties. The purpose was to show that for large molecules relativity effects could not be ignored and that these effects could be calculated and yield data in closer agreement to empirical measurements. Both the energy band structure and molecular orbitals are depicted.

  18. Chemical process for the catalytic oxidation of formaldehyde and other organic compounds

    SciTech Connect

    Murphy, A.P.

    1991-01-01

    The invention discusses a chemical process for the catalytic oxidation of formaldehyde and other organic compounds contained in a dilute aqueous solution, particularly waste water. The inventive feature resides in the use of a cobalt catalyst to increase the rate of oxidation of the organic compounds when hypochlorous acid is the oxidant. The latter may be provided by a chlorine compound, such as sodium hypochlorite, calcium hypochlorite or chlorine gas dissolved in water.

  19. Revealing of Biological Activity in Crude Extracts, Seperated Fractions, Groups of Chemical Substance and Individual Compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crude extracts, separated fractions, groups of chemical substances, and individual compounds from natural sources are all evaluated stepwise while performing purifications in in-house bioassays. In a stepwise fashion proceeding from crude extracts to fractions and on to pure compounds, decisions ar...

  20. Sources of toxicity and exposure information for identifying chemicals of high concern to children

    SciTech Connect

    Stone, Alex; Delistraty, Damon

    2010-11-15

    Due to the large number of chemicals in commerce without adequate toxicity characterization data, coupled with an ineffective federal policy for chemical management in the United States, many states are grappling with the challenge to identify toxic chemicals that may pose a risk to human health and the environment. Specific populations (e.g., children, elderly) are particularly sensitive to these toxic chemicals. In 2008, the Children's Safe Product Act (CSPA) was passed in Washington State. The CSPA included specific requirements to identify High Priority Chemicals (HPCs) and Chemicals of High Concern to Children (CHCCs). To implement this legislation, a methodology was developed to identify HPCs from authoritative scientific and regulatory sources on the basis of toxicity criteria. Another set of chemicals of concern was then identified from authoritative sources, based on their potential exposure to children. Exposure potential was evaluated by identifying chemicals detected in biomonitoring studies (i.e., human tissues), as well as those present in residential exposure media (e.g., indoor air, house dust, drinking water, consumer products). Accordingly, CHCCs were defined as HPCs that also appear in biomonitoring studies or relevant exposure media. For chemicals with unique Chemical Abstracts Service (CAS) numbers, we identified 2044 HPCs and 2219 chemicals with potential exposure to children, resulting in 476 CHCCs. The process of chemical identification is dynamic, so that chemicals may be added or subtracted as new information becomes available. Although beyond the scope of this paper, the 476 CHCCs will be prioritized in a more detailed assessment, based on the strength and weight of evidence of toxicity and exposure data. Our approach was developed to be flexible which allows the addition or removal of specific sources of toxicity or exposure information, as well as transparent to allow clear identification of inputs. Although the methodology was constrained by specific requirements in the CSPA, the intent of this work was to identify HPCs and CHCCs that might guide future regulatory actions and inform chemical management policies, aimed at protecting children's health.

  1. Chemical genomic profiling via barcode sequencing to predict compound mode of action

    PubMed Central

    Piotrowski, Jeff S.; Simpkins, Scott W.; Li, Sheena C.; Deshpande, Raamesh; McIlwain, Sean; Ong, Irene; Myers, Chad L.; Boone, Charlie; Andersen, Raymond J.

    2015-01-01

    Summary Chemical genomics is an unbiased, whole-cell approach to characterizing novel compounds to determine mode of action and cellular target. Our version of this technique is built upon barcoded deletion mutants of Saccharomyces cerevisiae and has been adapted to a high-throughput methodology using next-generation sequencing. Here we describe the steps to generate a chemical genomic profile from a compound of interest, and how to use this information to predict molecular mechanism and targets of bioactive compounds. PMID:25618354

  2. GIAO chemical shifts calculations of some polycyclic cage compounds: Unambiguous assignment of NMR signals and stereoisomers

    NASA Astrophysics Data System (ADS)

    Salles, Roberta C.; Lacerda, Valdemar; Barbosa, Layla Rosário; Ito, Felícia M.; de Lima, Dênis P.; dos Santos, Reginaldo B.; Greco, Sandro J.; Neto, Álvaro C.; de Castro, Eustáquio V. R.; Beatriz, Adilson

    2012-01-01

    GIAO model at DFT/B3LYP level of theory using the cc-pVTZ basis set was employed for calculations of 1H and 13C NMR chemical shifts ( ?) for various rigid polycyclic compounds. The data obtained were used as an auxiliary tool to an unequivocal assignment of all 1H and 13C NMR signals and the endo/ exo stereochemistry of the strained compounds studied. For these compounds the theoretical model adopted was sufficient to obtain a good description of chemical shifts.

  3. Radiation induced chemical changes of phenolic compounds in strawberries

    NASA Astrophysics Data System (ADS)

    Breitfellner, F.; Solar, S.; Sontag, G.

    2003-06-01

    In unirradiated strawberries four phenolic acids (gallic acid, p-coumaric acid, caffeic acid and 4-hydroxybenzoic acid), the flavonoids (+)-catechin, (-)-epicatechin and glycosides from kaempferol and quercetin were determined by reversed phase chromatography with diode array detection. Characteristic linear dose/concentration relationships were found for 4-hydroxybenzoic acid and two unidentified compounds. One of them may be usable as marker to prove an irradiation treatment.

  4. CHEMICAL SPECIATION OF INORGANIC COMPOUNDS UNDER HYDROTHERMAL CONDITIONS

    EPA Science Inventory

    This research will utilize the high-intensity x-rays available at the Advance Photon Source (APS) to study the inorganic chemistry occurring during the hydrothermal oxidation of tank waste and the chemistry associated with tank waste vitrification. Although the chemical conversio...

  5. Toxicological and chemical assessment of ordnance compounds in marine sediments and porewaters

    USGS Publications Warehouse

    Nipper, M.; Carr, R.S.; Biedenbach, J.M.; Hooten, R.L.; Miller, K.

    2002-01-01

    Toxicological and chemical studies were performed with a silty and a sandy marine sediment spiked with 2,6-dinitrotoluene (2,6-DNT), 2,4,6-trinitrophenylmethylnitramine (tetryl), or 2,4,6-trinitrophenol (picric acid). Whole sediment toxicity was analyzed by the 10-day survival test with the amphipod Ampelisca abdita, and porewater toxicity tests assessed macro-algae (Ulva fasciata) zoospore germination and germling growth, sea urchin (Arbacia punctulata) embryological development, and polychaete (Dinophilus gyrociliatus) survival and reproduction. Whole sediments spiked with 2,6-DNT were not toxic to amphipods. The fine-grained sediment spiked with tetryl was also not acutely toxic. The tetryl and picric acid LC50 values in the sandy sediment were 3.24 and 144 mg/kg dry weight, respectively. The fine-grained sediment spiked with picric acid generated a U-shaped concentration-response curve in the amphipod test, with increased survival both in the lowest and highest concentration. Grain-size distribution and organic carbon content strongly influenced the behavior of ordnance compounds in spiked sediments. Very low concentrations were measured in some of the treatments and irreversible binding and biodegradation are suggested as the processes responsible for the low measurements. Porewater toxicity varied with its sedimentary origin and with ordnance compound. The sea urchin embryological development test tended to be the least sensitive. Tetryl was the most toxic chemical in all porewater tests, and picric acid the least toxic. Samples spiked with 2,6-DNT contained a degradation product identified as 2-methyl-3-nitroaniline (also known as 2-amino-6-nitrotoluene), and unidentified peaks, possibly degradation products, were also seen in some of the picric acid- and tetryl-spiked samples. Degradation products may have played a role in observed toxicity. ?? 2002 Elsevier Science Ltd. All rights reserved.

  6. Chemical pneumonitis due to exposure to bromine compounds.

    PubMed

    Kraut, A; Lilis, R

    1988-07-01

    A 60-year-old laboratory technician developed pulmonary infiltrates consistent with chemical pneumonitis following accidental exposure to a mixture of hydrogen bromide and phosphorus tribromide. A protracted clinical course ensued consistent with bronchiolitis obliterans. These problems may have been avoided if the potential for subsequent damage had been realized at the time of the initial exposure. Health personnel must be aware of the potentially delayed effects of accidental exposures to respiratory irritants. PMID:3383640

  7. Anti-trypanosomal activities and structural chemical properties of selected compound classes.

    PubMed

    Ponte-Sucre, Alicia; Bruhn, Heike; Schirmeister, Tanja; Cecil, Alexander; Albert, Christian R; Buechold, Christian; Tischer, Maximilian; Schlesinger, Susanne; Goebel, Tim; Fuß, Antje; Mathein, Daniela; Merget, Benjamin; Sotriffer, Christoph A; Stich, August; Krohne, Georg; Engstler, Markus; Bringmann, Gerhard; Holzgrabe, Ulrike

    2015-02-01

    Potent compounds do not necessarily make the best drugs in the market. Consequently, with the aim to describe tools that may be fundamental for refining the screening of candidates for animal and preclinical studies and further development, molecules of different structural classes synthesized within the frame of a broad screening platform were evaluated for their trypanocidal activities, cytotoxicities against murine macrophages J774.1 and selectivity indices, as well as for their ligand efficiencies and structural chemical properties. To advance into their modes of action, we also describe the morphological and ultrastructural changes exerted by selected members of each compound class on the parasite Trypanosoma brucei. Our data suggest that the potential organelles targeted are either the flagellar pocket (compound 77, N-Arylpyridinium salt; 15, amino acid derivative with piperazine moieties), the endoplasmic reticulum membrane systems (37, bisquaternary bisnaphthalimide; 77, N-Arylpyridinium salt; 68, piperidine derivative), or mitochondria and kinetoplasts (88, N-Arylpyridinium salt; 68, piperidine derivative). Amino acid derivatives with fumaric acid and piperazine moieties (4, 15) weakly inhibiting cysteine proteases seem to preferentially target acidic compartments. Our results suggest that ligand efficiency indices may be helpful to learn about the relationship between potency and chemical characteristics of the compounds. Interestingly, the correlations found between the physico-chemical parameters of the selected compounds and those of commercial molecules that target specific organelles indicate that our rationale might be helpful to drive compound design toward high activities and acceptable pharmacokinetic properties for all compound families. PMID:25416330

  8. Nanoparticles made of ?-conjugated compounds targeted for chemical and biological applications.

    PubMed

    Xu, Xinjun; Liu, Ronghua; Li, Lidong

    2015-12-01

    Semiconducting organic nanoparticles have recently attracted increasing attention in the chemical and biomedical fields. Such nanoparticles are mainly composed of ?-conjugated compounds. They possess the properties of easy synthesis, facile tuning, less toxicity and more biocompatibility relative to the existing inorganic nanoparticles. In addition, they show advantages such as brighter fluorescence, higher photostability and higher biocompatibility, compared with classical fluorescent organic dyes. In this review, we summarize the latest advances in the development of organic nanoparticles made of ?-conjugated compounds, including preparation methods, material design, nanoparticle fabrication and surface functionalization for chemical and biological applications. Especially, we focus on the applications of semiconducting organic nanoparticles in chemical and biological sensing by monitoring the fluorescence signal, as nanocarriers for drug/gene delivery, in photothermal and photodynamic therapy, and in photoacoustic imaging. Finally, the challenges and perspectives for the future development of organic nanoparticles based on ?-conjugated compounds are also discussed. PMID:26427025

  9. Prediction of the rodent carcinogenicity of organic compounds from their chemical structures using the FALS method.

    PubMed Central

    Moriguchi, I; Hirano, H; Hirono, S

    1996-01-01

    Fuzzy adaptive least-squares (FALS), a pattern recognition method recently developed in our laboratory for correlating structure with activity rating, was used to generate quantitative structure-activity relationship (QSAR) models on the carcinogenicity of organic compounds of several chemical classes. Using the predictive models obtained from the chemical class-based FALS QSAR approach, the rodent carcinogenicity or noncarcinogenicity of a group of organic chemicals currently being tested by the U.S. National Toxicology Program was estimated from their chemical structures. PMID:8933054

  10. Title III section 313 release reporting guidance: Estimating chemical releases from rubber production and compounding

    SciTech Connect

    Not Available

    1988-03-01

    Facilities engaged in rubber production and compounding may be required to report annually any releases to the environment of certain chemicals regulated under Section 313, Title III, of the Superfund Amendments and Reauthorization Act (SARA) of 1986. The document has been developed to assist those who produce rubber in the completion of Part III (Chemical Specific Information) of the Toxic Chemical Release Inventory Reporting Form. Included herein is general information on toxic chemicals used and process wastes generated, along with several examples to demonstrate the types of data needed and various methodologies available for estimating releases.

  11. Prediction of the rodent carcinogenicity of organic compounds from their chemical structures using the FALS method

    SciTech Connect

    Moriguchi, Ikuo; Hirono, Shuichi; Hirano, Hiroyuki

    1996-10-01

    Fuzzy adaptive least-squares (FALS), a pattern recognition method recently developed in our laboratory for correlating structure with activity rating, was used to generate quantitative structure-activity relationship (QSAR) models on the carcinogenicity of organic compounds of several chemical classes. Using the predictive models obtained from the chemical class-based FALS QSAR approach, the rodent carcinogenicity or noncarcinogenicity of a group of organic chemicals currently being tested by the U.S. National Toxicology Program was estimated from their chemical structures. 12 refs., 4 tabs.

  12. Combining Non Selective Gas Sensors on a Mobile Robot for Identification and Mapping of Multiple Chemical Compounds

    PubMed Central

    Victor Hernandez, Bennetts; Schaffernicht, Erik; Pomareda, Victor; Lilienthal, Achim J.; Marco, Santiago; Trincavelli, Marco

    2014-01-01

    In this paper, we address the task of gas distribution modeling in scenarios where multiple heterogeneous compounds are present. Gas distribution modeling is particularly useful in emission monitoring applications where spatial representations of the gaseous patches can be used to identify emission hot spots. In realistic environments, the presence of multiple chemicals is expected and therefore, gas discrimination has to be incorporated in the modeling process. The approach presented in this work addresses the task of gas distribution modeling by combining different non selective gas sensors. Gas discrimination is addressed with an open sampling system, composed by an array of metal oxide sensors and a probabilistic algorithm tailored to uncontrolled environments. For each of the identified compounds, the mapping algorithm generates a calibrated gas distribution model using the classification uncertainty and the concentration readings acquired with a photo ionization detector. The meta parameters of the proposed modeling algorithm are automatically learned from the data. The approach was validated with a gas sensitive robot patrolling outdoor and indoor scenarios, where two different chemicals were released simultaneously. The experimental results show that the generated multi compound maps can be used to accurately predict the location of emitting gas sources. PMID:25232911

  13. Combining non selective gas sensors on a mobile robot for identification and mapping of multiple chemical compounds.

    PubMed

    Bennetts, Victor Hernandez; Schaffernicht, Erik; Pomareda, Victor; Lilienthal, Achim J; Marco, Santiago; Trincavelli, Marco

    2014-01-01

    In this paper, we address the task of gas distribution modeling in scenarios where multiple heterogeneous compounds are present. Gas distribution modeling is particularly useful in emission monitoring applications where spatial representations of the gaseous patches can be used to identify emission hot spots. In realistic environments, the presence of multiple chemicals is expected and therefore, gas discrimination has to be incorporated in the modeling process. The approach presented in this work addresses the task of gas distribution modeling by combining different non selective gas sensors. Gas discrimination is addressed with an open sampling system, composed by an array of metal oxide sensors and a probabilistic algorithm tailored to uncontrolled environments. For each of the identified compounds, the mapping algorithm generates a calibrated gas distribution model using the classification uncertainty and the concentration readings acquired with a photo ionization detector. The meta parameters of the proposed modeling algorithm are automatically learned from the data. The approach was validated with a gas sensitive robot patrolling outdoor and indoor scenarios, where two different chemicals were released simultaneously. The experimental results show that the generated multi compound maps can be used to accurately predict the location of emitting gas sources. PMID:25232911

  14. Gametocytocidal Screen Identifies Novel Chemical Classes with Plasmodium falciparum Transmission Blocking Activity

    PubMed Central

    Sanders, Natalie G.; Sullivan, David J.; Mlambo, Godfree; Dimopoulos, George; Tripathi, Abhai K.

    2014-01-01

    Discovery of transmission blocking compounds is an important intervention strategy necessary to eliminate and eradicate malaria. To date only a small number of drugs that inhibit gametocyte development and thereby transmission from the mosquito to the human host exist. This limitation is largely due to a lack of screening assays easily adaptable to high throughput because of multiple incubation steps or the requirement for high gametocytemia. Here we report the discovery of new compounds with gametocytocidal activity using a simple and robust SYBR Green I- based DNA assay. Our assay utilizes the exflagellation step in male gametocytes and a background suppressor, which masks the staining of dead cells to achieve healthy signal to noise ratio by increasing signal of viable parasites and subtracting signal from dead parasites. By determining the contribution of exflagellation to fluorescent signal and using appropriate cutoff values, we were able to screen for gametocytocidal compounds. After assay validation and optimization, we screened an FDA approved drug library of approximately 1500 compounds, as well as the 400 compound MMV malaria box and identified 44 gametocytocidal compounds with sub to low micromolar IC50s. Major classes of compounds with gametocytocidal activity included quaternary ammonium compounds with structural similarity to choline, acridine-like compounds similar to quinacrine and pyronaridine, as well as antidepressant, antineoplastic, and anthelminthic compounds. Top drug candidates showed near complete transmission blocking in membrane feeding assays. This assay is simple, reproducible and demonstrated robust Z-factor values at low gametocytemia levels, making it amenable to HTS for identification of novel and potent gametocytocidal compounds. PMID:25157792

  15. Potential hazards to embryo implantation: A human endometrial in vitro model to identify unwanted antigestagenic actions of chemicals

    SciTech Connect

    Fischer, L.; Deppert, W.R.; Pfeifer, D.; Stanzel, S.; Weimer, M.; Hanjalic-Beck, A.; Stein, A.; Straßer, M.; Zahradnik, H.P.; Schaefer, W.R.

    2012-05-01

    Embryo implantation is a crucial step in human reproduction and depends on the timely development of a receptive endometrium. The human endometrium is unique among adult tissues due to its dynamic alterations during each menstrual cycle. It hosts the implantation process which is governed by progesterone, whereas 17?-estradiol regulates the preceding proliferation of the endometrium. The receptors for both steroids are targets for drugs and endocrine disrupting chemicals. Chemicals with unwanted antigestagenic actions are potentially hazardous to embryo implantation since many pharmaceutical antiprogestins adversely affect endometrial receptivity. This risk can be addressed by human tissue-specific in vitro assays. As working basis we compiled data on chemicals interacting with the PR. In our experimental work, we developed a flexible in vitro model based on human endometrial Ishikawa cells. Effects of antiprogestin compounds on pre-selected target genes were characterized by sigmoidal concentration–response curves obtained by RT-qPCR. The estrogen sulfotransferase (SULT1E1) was identified as the most responsive target gene by microarray analysis. The agonistic effect of progesterone on SULT1E1 mRNA was concentration-dependently antagonized by RU486 (mifepristone) and ZK137316 and, with lower potency, by 4-nonylphenol, bisphenol A and apigenin. The negative control methyl acetoacetate showed no effect. The effects of progesterone and RU486 were confirmed on the protein level by Western blotting. We demonstrated proof of principle that our Ishikawa model is suitable to study quantitatively effects of antiprogestin-like chemicals on endometrial target genes in comparison to pharmaceutical reference compounds. This test is useful for hazard identification and may contribute to reduce animal studies. -- Highlights: ? We compare progesterone receptor-mediated endometrial effects of chemicals and drugs. ? 4-Nonylphenol, bisphenol A and apigenin exert weak antigestagenic activity. ? SULT1E1 is a significant marker for endometrial antiprogestin effects. ? Ishikawa cells are a tissue-specific approach for characterization of SPRMs. ? Chemicals acting as progesterone receptor antagonists may exert antifertility effects.

  16. Lithium-benzene sandwich compounds : a quantum chemical study.

    SciTech Connect

    Vollmer, J. M.; Kandalam, A.; Curtiss, L. A.

    2002-10-17

    The structures and dissociation energies of Li{sub n}{center_dot}(C{sub 6}H{sub 6}){sub n+1} sandwich complexes (n = 1-6) have been investigated using quantum chemical techniques. At the G3(MP2) level of theory, the Li{center_dot}(C{sub 6}H{sub 6}){sub 2} complex exhibits a Jahn-Teller distortion, forming a D{sub 2h} charge-separated species [C{sub 6}H{sub 6}{sup -1/2}-Li{sup +}-C{sub 6}H{sub 6}{sup -1/2}] with a surprisingly large dissociation energy of 0.85 eV, and a short benzene-benzene distance of 3.54 Angstroms. Comparisons are made with the Li{center_dot}C{sub 6}H{sub 6}, Li{sup +}{center_dot}C{sub 6}H{sub 6}, and Li{sup +}{center_dot}(C{sub 6}H{sub 6}){sub 2} complexes. The larger (n > 1) complexes were studied at the B3LYP/6-31G(d) level and were also found to have large dissociation energies, ca. 0.85 eV per Li atom, and short benzene-benzene distances (3.70 Angstroms).

  17. Yeast Chemical Genetics For Identifying Regulators of Late Secretory Traffic Pathways

    E-print Network

    Zhang, Lisha

    2011-04-25

    was to use a yeast chemical genetic strategy to identify components of the exocytic transport machinery, and to generate useful chemical tools that will help us to understand how the machinery functions. I analyzed the effects of small molecules that we...

  18. Identifying Alternative Conceptions of Chemical Kinetics among Secondary School and Undergraduate Students in Turkey

    ERIC Educational Resources Information Center

    Cakmakci, Gultekin

    2010-01-01

    This study identifies some alternative conceptions of chemical kinetics held by secondary school and undergraduate students (N = 191) in Turkey. Undergraduate students who participated are studying to become chemistry teachers when they graduate. Students' conceptions about chemical kinetics were elicited through a series of written tasks and…

  19. Identification and quantitative analysis of chemical compounds based on multiscale linear fitting of terahertz spectra

    NASA Astrophysics Data System (ADS)

    Qiao, Lingbo; Wang, Yingxin; Zhao, Ziran; Chen, Zhiqiang

    2014-07-01

    Terahertz (THz) time-domain spectroscopy is considered as an attractive tool for the analysis of chemical composition. The traditional methods for identification and quantitative analysis of chemical compounds by THz spectroscopy are all based on full-spectrum data. However, intrinsic features of the THz spectrum only lie in absorption peaks due to existence of disturbances, such as unexpected components, scattering effects, and barrier materials. We propose a strategy that utilizes Lorentzian parameters of THz absorption peaks, extracted by a multiscale linear fitting method, for both identification of pure chemicals and quantitative analysis of mixtures. The multiscale linear fitting method can automatically remove background content and accurately determine Lorentzian parameters of the absorption peaks. The high recognition rate for 16 pure chemical compounds and the accurate predicted concentrations for theophylline-lactose mixtures demonstrate the practicability of our approach.

  20. Relationships between chemical structure and rat repellency. II. Compounds screened between 1950 and 1960

    USGS Publications Warehouse

    Bowles, W.A.; Adomaitis, V.A.; DeWitt, J.B.; Pratt, J.J., Jr.

    1974-01-01

    Over 4,600 compounds, chiefly organic types, were evaluated using both a food acceptance test (Part A) and a barrier penetration bioassay (Part B), to correlate relationships between chemical structure and rodent repellency.These chemicals are indexed and classified according to the functional groups present and to the degree of substitution within their molecular structures. The results of reduction in foot consumption for each compound appraised are calculated and their K values listed in Table I.The repellent activities of the functional groups represented, alone or in combinations, are expressed in Table II by a Functional Group Repellency Index. A ranking of these indices suggests that acyclic and heteroyclic compounds containing tri- or pentavalent nitrogen would be a parent compound of choice for synthesizing novel repellents. Other molecular arrangements, spatial configurations and combinations of functional groups are compared.There were 123 active, interesting or promising compounds included in the 699 having K values of 85 or greater, which were selected for the barrier appraisal study. These chemicals were formulated in selective solvents at several concentrations and applied to burlap. Small foot bags were fashioned using the fabric impregnated with the candidate formulation, and exposed to rodent attack following storage periods of varying intervals. The results of these tests are listed in Table III. Again, those compounds containing nitrogen in the functional groupings indicated a high order of effectiveness. Several commercial patents covering rodent repellents were issued using the data from the food acceptance and barrier studies.Organizations and cooperators which supplied samples for the program are listed in Appendix I. The Wiswesser cipher for compounds in Table I is used in Appendix II to facilitate location of chemicals by sample code number as they appear under the index headings, and for computer storage and analysis.

  1. Relationships between chemical structure and rat repellency: II. compounds screened between 1950 and 1960

    USGS Publications Warehouse

    Bowles, Walter A.; Adomaitis, V.A.; DeWitt, J.B.; Pratt, J.J., Jr.

    1974-01-01

    Over 4,600 compounds, chiefly organic types, were evaluated using both a food acceptance test (Part A) and a barrier penetration bioassay (Part B), to correlate relationships between chemical structure and rodent repellency. These chemicals are indexed and classified according to the functional groups present and to the degree of substitution within their molecular structures. The results of reduction in food consumption for each compound appraised are calculated and their K values listed in Table 1. The repellent activities of the functional groups represented, alone or in combinations, are expressed in Table II by a Functional Group Repellency Index.. A ranking of these indices suggests that acyclic and heteroyclic compounds containing tri- or pentavalent nitrogen would be a parent compound of choice for synthesizing novel repellents. Other molecular arrangements, spatial configurations and combinations of functional groups are compared. There were 123 active, interesting or promising compounds included in the 699 having K values of 85 or greater, which were selected for the barrier appraisal study. These chemicals were formulated in selective solvents at several concentrations and applied to burlap. Small food bags were fashioned using the fabric impregnated with the candidate formulation, and exposed to rodent attack following storage periods of varying intervals. The results of these tests are listed in Table III. Again, those compounds containing nitrogen in the functional groupings indicated a high order of effectiveness. Several commercial patents covering rodent repellents were issued using the data from the food acceptance and barrier studies. Organizations and cooperators which supplied samples for the program are listed in Appendix I. The Wiswesser cipher for compounds in Table I is used in Appendix II to facilitate location of chemicals by sample code number as they appear under the index headings, and for computer storage and analysis.

  2. High-throughput chemical screening identifies AG-490 as a stimulator of aquaporin 2 membrane expression and urine concentration.

    PubMed

    Nomura, Naohiro; Nunes, Paula; Bouley, Richard; Nair, Anil V; Shaw, Stanley; Ueda, Erica; Pathomthongtaweechai, Nutthapoom; Lu, Hua A Jenny; Brown, Dennis

    2014-10-01

    A reduction or loss of plasma membrane aquaporin 2 (AQP2) in kidney principal cells due to defective vasopressin (VP) signaling through the VP receptor causes excessive urine production, i.e., diabetes insipidus. The amount of AQP2 on the plasma membrane is regulated by a balance of exocytosis and endocytosis and is the rate limiting step for water reabsorption in the collecting duct. We describe here a systematic approach using high-throughput screening (HTS) followed by in vitro and in vivo assays to discover novel compounds that enhance vasopressin-independent AQP2 membrane expression. We performed initial chemical library screening with a high-throughput exocytosis fluorescence assay using LLC-PK1 cells expressing soluble secreted yellow fluorescent protein and AQP2. Thirty-six candidate exocytosis enhancers were identified. These compounds were then rescreened in AQP2-expressing cells to determine their ability to increase AQP2 membrane accumulation. Effective drugs were then applied to kidney slices in vitro. Three compounds, AG-490, ?-lapachone, and HA14-1 increased AQP2 membrane accumulation in LLC-PK1 cells, and both AG-490 and ?-lapachone were also effective in MDCK cells and principal cells in rat kidney slices. Finally, one compound, AG-490 (an EGF receptor and JAK-2 kinase inhibitor), decreased urine volume and increased urine osmolality significantly in the first 2-4 h after a single injection into VP-deficient Brattleboro rats. In conclusion, we have developed a systematic procedure for identifying new compounds that modulate AQP2 trafficking using initial HTS followed by in vitro assays in cells and kidney slices, and concluding with in vivo testing in an animal model. PMID:24944200

  3. Large-scale neurochemical metabolomics analysis identifies multiple compounds associated with methamphetamine exposure.

    PubMed

    McClay, Joseph L; Adkins, Daniel E; Vunck, Sarah A; Batman, Angela M; Vann, Robert E; Clark, Shaunna L; Beardsley, Patrick M; van den Oord, Edwin J C G

    2013-04-01

    Methamphetamine (MA) is an illegal stimulant drug of abuse with serious negative health consequences. The neurochemical effects of MA have been partially characterized, with a traditional focus on classical neurotransmitter systems. However, these directions have not yet led to novel drug treatments for MA abuse or toxicity. As an alternative approach, we describe here the first application of metabolomics to investigate the neurochemical consequences of MA exposure in the rodent brain. We examined single exposures at 3 mg/kg and repeated exposures at 3 mg/kg over 5 days in eight common inbred mouse strains. Brain tissue samples were assayed using high-throughput gas and liquid chromatography mass spectrometry, yielding quantitative data on >300 unique metabolites. Association testing and false discovery rate control yielded several metabolome-wide significant associations with acute MA exposure, including compounds such as lactate (p = 4.4 × 10(-5), q = 0.013), tryptophan (p = 7.0 × 10(-4), q = 0.035) and 2-hydroxyglutarate (p = 1.1 × 10(-4), q = 0.022). Secondary analyses of MA-induced increase in locomotor activity showed associations with energy metabolites such as succinate (p = 3.8 × 10(-7)). Associations specific to repeated (5 day) MA exposure included phosphocholine (p = 4.0 × 10(-4), q = 0.087) and ergothioneine (p = 3.0 × 10(-4), q = 0.087). Our data appear to confirm and extend existing models of MA action in the brain, whereby an initial increase in energy metabolism, coupled with an increase in behavioral locomotion, gives way to disruption of mitochondria and phospholipid pathways and increased endogenous antioxidant response. Our study demonstrates the power of comprehensive MS-based metabolomics to identify drug-induced changes to brain metabolism and to develop neurochemical models of drug effects. PMID:23554582

  4. Large-scale neurochemical metabolomics analysis identifies multiple compounds associated with methamphetamine exposure

    PubMed Central

    Adkins, Daniel E.; Vunck, Sarah A.; Batman, Angela M.; Vann, Robert E.; Clark, Shaunna L.; Beardsley, Patrick M.; van den Oord, Edwin J. C. G.

    2012-01-01

    Methamphetamine (MA) is an illegal stimulant drug of abuse with serious negative health consequences. The neurochemical effects of MA have been partially characterized, with a traditional focus on classical neurotransmitter systems. However, these directions have not yet led to novel drug treatments for MA abuse or toxicity. As an alternative approach, we describe here the first application of metabolomics to investigate the neurochemical consequences of MA exposure in the rodent brain. We examined single exposures at 3 mg/kg and repeated exposures at 3 mg/kg over 5 days in eight common inbred mouse strains. Brain tissue samples were assayed using high-throughput gas and liquid chromatography mass spectrometry, yielding quantitative data on >300 unique metabolites. Association testing and false discovery rate control yielded several metabolome-wide significant associations with acute MA exposure, including compounds such as lactate (p = 4.4 × 10?5, q = 0.013), tryptophan (p = 7.0 × 10?4, q = 0.035) and 2-hydroxyglutarate (p = 1.1 × 10?4, q = 0.022). Secondary analyses of MA-induced increase in locomotor activity showed associations with energy metabolites such as succinate (p = 3.8 × 10?7). Associations specific to repeated (5 day) MA exposure included phosphocholine (p = 4.0 × 10?4, q = 0.087) and ergothioneine (p = 3.0 × 10?4, q = 0.087). Our data appear to confirm and extend existing models of MA action in the brain, whereby an initial increase in energy metabolism, coupled with an increase in behavioral locomotion, gives way to disruption of mitochondria and phospholipid pathways and increased endogenous antioxidant response. Our study demonstrates the power of comprehensive MS-based metabolomics to identify drug-induced changes to brain metabolism and to develop neurochemical models of drug effects. PMID:23554582

  5. Identifying biologically active compound classes using phenotypic screening data and sampling statistics.

    PubMed

    Klekota, Justin; Brauner, Erik; Schreiber, Stuart L

    2005-01-01

    Scoring the activity of compounds in phenotypic high-throughput assays presents a unique challenge because of the limited resolution and inherent measurement error of these assays. Techniques that leverage the structural similarity of compounds within an assay can be used to improve the hit-recovery rate from screening data. A technique is presented that uses clustering and sampling statistics to predict likely compound activity by scoring entire structural classes. A set of phenotypic assays performed against a commercially available compound library was used as a test set. Using the class-scoring technique, the resultant activity prediction scores were more reproducible than individual assay measurements, and class scoring recovered known active compounds more efficiently than individual assay measurements because class scoring had fewer false positives. Known biologically active compounds were recovered 87% of the time using class scores, suggesting a low false-negative rate that compared well to individual assay measurements. In addition, many weak and potentially novel classes of active compounds, overlooked by individual assay measurements, were suggested. PMID:16309290

  6. Characterization of Spatial Repellent, Contact Irritant and Toxicant Chemical Actions of Standard Vector Control Compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A previously described modular high-throughput screening system (HITTS) was used to characterize the spatial repellent, contact irritant and toxicant chemical actions of 14 compounds with a history of use in vector control. The response of F1-F4 Aedes aegypti to various concentrations of four organo...

  7. Chemical mutagenesis testing in Drosophila. VII. Results of 22 coded compounds tested in larval feeding experiments

    SciTech Connect

    Zimmering, S.; Mason, J.M.; Valencia, R. )

    1989-01-01

    Twenty-two chemicals were tested for mutagenicity in the sex-linked recessive lethal (SLRL) mutation assay after being fed to Drosophila melanogaster larvae. One compound, maleic hydrazide, was found to be mutagenic. It was tested for the ability to produce reciprocal translocations (RTs) and was positive in that assay as well.

  8. Percolated water can leach undesirable chemical compounds below the rooting zone of plants and

    E-print Network

    Percolated water can leach undesirable chemical compounds below the rooting zone of plants for salts and pollutants, the contamination of streams, rivers, lakes, and groundwater resources poses a great threat to plant and animal health, the environment, the economy, and civilization. Further Reading

  9. Antibacterial activity of coffee extracts and selected coffee chemical compounds against enterobacteria.

    PubMed

    Almeida, Ana Amélia P; Farah, Adriana; Silva, Daniela A M; Nunan, Elzíria A; Glória, M Beatriz A

    2006-11-15

    The in vitro antimicrobial activity of commercial coffee extracts and chemical compounds was investigated on nine strains of enterobacteria. The antimicrobial activity investigated by the disc diffusion method was observed in both the extracts and tested chemical compounds. Even though pH, color, and the contents of trigonelline, caffeine, and chlorogenic acids differed significantly among the coffee extracts, no significant differences were observed in their antimicrobial activity. Caffeic acid and trigonelline showed similar inhibitory effect against the growth of the microorganisms. Caffeine, chlorogenic acid, and protocatechuic acid showed particularly strong effect against Serratia marcescens and Enterobacter cloacae. The IC(50) and IC(90) for the compounds determined by the microtiter plate method indicated that trigonelline, caffeine, and protocatechuic acids are potential natural antimicrobial agents against Salmonella enterica. The concentrations of caffeine found in coffee extracts are enough to warrant 50% of the antimicrobial effect against S. enterica, which is relevant to human safety. PMID:17090115

  10. Chemical Compounds Toxic to Invertebrates Isolated from Marine Cyanobacteria of Potential Relevance to the Agricultural Industry

    PubMed Central

    Essack, Magbubah; Alzubaidy, Hanin S.; Bajic, Vladimir B.; Archer, John A. C.

    2014-01-01

    In spite of advances in invertebrate pest management, the agricultural industry is suffering from impeded pest control exacerbated by global climate changes that have altered rain patterns to favour opportunistic breeding. Thus, novel naturally derived chemical compounds toxic to both terrestrial and aquatic invertebrates are of interest, as potential pesticides. In this regard, marine cyanobacterium-derived metabolites that are toxic to both terrestrial and aquatic invertebrates continue to be a promising, but neglected, source of potential pesticides. A PubMed query combined with hand-curation of the information from retrieved articles allowed for the identification of 36 cyanobacteria-derived chemical compounds experimentally confirmed as being toxic to invertebrates. These compounds are discussed in this review. PMID:25356733

  11. Identifying new small molecule anti-invasive compounds for glioma treatment

    PubMed Central

    Munson, Jennifer; Bonner, Michael; Fried, Levi; Hofmekler, Jonathan; Arbiser, Jack; Bellamkonda, Ravi

    2013-01-01

    Glioblastoma is a disease with poor survival rates after diagnosis. Treatment of the disease involves debulking of the tumor, which is limited by the degree of invasiveness of the disease. Therefore, a treatment to halt the invasion of glioma is desirable for clinical implementation. There have been several candidate compounds targeting specific aspects of invasion, including cell adhesions, matrix degradation, and cytoskeletal rearrangement, but they have failed clinically for a variety of reasons. New targets against glioma invasion include upstream mediators of these classical targets in an effort to better inhibit invasion with more specificity for cancer. Included in these treatments is a new class of compounds inhibiting the generation of reactive oxygen species by targeting the NADPH oxidases. These compounds stand to inhibit multiple pathways, including nuclear factor kappa B and Akt. By conducting a screen of compounds thought to inhibit these pathways, a new compound to halt invasion was found that may have a beneficial effect against glioma, based on recent publications. Further, there are still limitations to the treatment of glioblastoma regardless of the discovery of new targets and compounds that should be addressed to better the therapies against this deadly cancer. PMID:24067366

  12. Drug Discovery for Schistosomiasis: Hit and Lead Compounds Identified in a Library of Known Drugs by Medium-Throughput Phenotypic Screening

    PubMed Central

    Wolff, Brian; Snedecor, June; Lim, Kee-Chong; Xu, Fengyun; Renslo, Adam R.; Williams, Janice; McKerrow, James H.; Caffrey, Conor R.

    2009-01-01

    Background Praziquantel (PZQ) is the only widely available drug to treat schistosomiasis. Given the potential for drug resistance, it is prudent to search for novel therapeutics. Identification of anti-schistosomal chemicals has traditionally relied on phenotypic (whole organism) screening with adult worms in vitro and/or animal models of disease—tools that limit automation and throughput with modern microtiter plate-formatted compound libraries. Methods A partially automated, three-component phenotypic screen workflow is presented that utilizes at its apex the schistosomular stage of the parasite adapted to a 96-well plate format with a throughput of 640 compounds per month. Hits that arise are subsequently screened in vitro against adult parasites and finally for efficacy in a murine model of disease. Two GO/NO GO criteria filters in the workflow prioritize hit compounds for tests in the animal disease model in accordance with a target drug profile that demands short-course oral therapy. The screen workflow was inaugurated with 2,160 chemically diverse natural and synthetic compounds, of which 821 are drugs already approved for human use. This affords a unique starting point to ‘reposition’ (re-profile) drugs as anti-schistosomals with potential savings in development timelines and costs. Findings Multiple and dynamic phenotypes could be categorized for schistosomula and adults in vitro, and a diverse set of ‘hit’ drugs and chemistries were identified, including anti-schistosomals, anthelmintics, antibiotics, and neuromodulators. Of those hits prioritized for tests in the animal disease model, a number of leads were identified, one of which compares reasonably well with PZQ in significantly decreasing worm and egg burdens, and disease-associated pathology. Data arising from the three components of the screen are posted online as a community resource. Conclusions To accelerate the identification of novel anti-schistosomals, we have developed a partially automated screen workflow that interfaces schistosomula with microtiter plate-formatted compound libraries. The workflow has identified various compounds and drugs as hits in vitro and leads, with the prescribed oral efficacy, in vivo. Efforts to improve throughput, automation, and rigor of the screening workflow are ongoing. PMID:19597541

  13. Chemical constituents of peppers (Piper spp.) and application to food preservation: naturally occurring antioxidative compounds.

    PubMed

    Nakatani, N; Inatani, R; Ohta, H; Nishioka, A

    1986-08-01

    In a structure analysis of the compounds of the genus Piper (Family Piperaceae), we identified five phenolic amides from Piper nigrum, seven compounds from P. retrofractum, and two compounds from P. baccatum. All the phenolic amides possess significant antioxidant activities that are more effective than the naturally occurring antioxidant, alpha-tocopherol. One amide, feruperine, has antioxidant activity as high as the synthetic antioxidants, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Naturally occurring antioxidants, therefore, may surpass BHA and BHT in their ability to inactivate mutagens in food. PMID:3757949

  14. Chemical constituents of peppers (Piper spp.) and application to food preservation: naturally occurring antioxidative compounds.

    PubMed Central

    Nakatani, N; Inatani, R; Ohta, H; Nishioka, A

    1986-01-01

    In a structure analysis of the compounds of the genus Piper (Family Piperaceae), we identified five phenolic amides from Piper nigrum, seven compounds from P. retrofractum, and two compounds from P. baccatum. All the phenolic amides possess significant antioxidant activities that are more effective than the naturally occurring antioxidant, alpha-tocopherol. One amide, feruperine, has antioxidant activity as high as the synthetic antioxidants, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT). Naturally occurring antioxidants, therefore, may surpass BHA and BHT in their ability to inactivate mutagens in food. PMID:3757949

  15. Revisiting benzene cluster cations for the chemical ionization of dimethyl sulfide and select volatile organic compounds

    DOE PAGESBeta

    Kim, M. J.; Zoerb, M. C.; Campbell, N. R.; Zimmermann, K. J.; Blomquist, B. W.; Huebert, B. J.; Bertram, T. H.

    2015-10-01

    Benzene cluster cations were revisited as a sensitive and selective reagent ion for the chemical ionization of dimethyl sulfide (DMS) and a select group of volatile organic compounds (VOCs). Laboratory characterization was performed using both a new set of compounds (i.e. DMS, ?-caryophyllene) as well as previously studied VOCs (i.e., isoprene, ?-pinene). Using a field deployable chemical ionization time-of-flight mass spectrometer (CI-ToFMS), benzene cluster cations demonstrated high sensitivity (> 1 ncps ppt?1) to DMS, isoprene, and ?-pinene standards. Parallel measurements conducted using a chemical-ionization quadrupole mass spectrometer, with a weaker electric field, demonstrated that ion-molecule reactions likely proceed through amore »combination of ligand-switching and direct charge transfer mechanisms. Laboratory tests suggest that benzene cluster cations may be suitable for the selective ionization of sesquiterpenes, where minimal fragmentation (R2=0.80) over a wide range of sampling conditions.« less

  16. Genetic and environmental factors affecting host response to drugs and other chemical compounds in our environment.

    PubMed Central

    Vesell, E S; Passananti, G T

    1977-01-01

    Compared to laboratory animals, humans are extremely heterogenous with respect to the many factors that can influence the distribution and biological effects of toxic chemicals. This heterogeneity can prevent an accurate assessment of the impact of a particular toxic compound on the health of an individual subject. Some of the factors that can significantly modify the host response to certain drugs, which serve in this review as a model for environmental chemicals, are enumerated and discussed. Although the mechanisms by which many of these factors modify the biological effects of certain environmental chemicals and drugs have been determined in some cases, better definition of the nature of interactions between these factors and environmental chemicals in a particular individual is required at a biochemical and molecular level. Recommendations are offered for the further development of our knowledge concerning interactions between environmental chemicals and such factors in a particular individual. PMID:598349

  17. Prediction of compounds in different local structure-activity relationship environments using emerging chemical patterns.

    PubMed

    Namasivayam, Vigneshwaran; Gupta-Ostermann, Disha; Balfer, Jenny; Heikamp, Kathrin; Bajorath, Jürgen

    2014-05-27

    Active compounds can participate in different local structure-activity relationship (SAR) environments and introduce different degrees of local SAR discontinuity, depending on their structural and potency relationships in data sets. Such SAR features have thus far mostly been analyzed using descriptive approaches, in particular, on the basis of activity landscape modeling. However, compounds in different local SAR environments have not yet been predicted. Herein, we adapt the emerging chemical patterns (ECP) method, a machine learning approach for compound classification, to systematically predict compounds with different local SAR characteristics. ECP analysis is shown to accurately assign many compounds to different local SAR environments across a variety of activity classes covering the entire range of observed local SARs. Control calculations using random forests and multiclass support vector machines were carried out and a variety of statistical performance measures were applied. In all instances, ECP calculations yielded comparable or better performance than controls. The approach presented herein can be applied to predict compounds that complement local SARs or prioritize compounds with different SAR characteristics. PMID:24803014

  18. Chemical characterisation of bioactive compounds in Medicago sativa growing in the desert of Oman.

    PubMed

    Hanif, Muhammad Asif; Al-Maskari, Ahmed Yahya; Al-Sabahi, Jamal Nasser; Al-Hdhrami, Ibtisam; Khan, Muhammad Mumtaz; Al-Azkawi, Ahlam; Hussain, Abdullah Ijaz

    2015-12-01

    Medicago sativa Linn growing in Omani desert were chemically characterised using flame photometry, inductively coupled plasma, gas chromatography-mass spectrometry and high performance liquid chromatographic (HPLC) analysis. HPLC analyses were performed to determine the phenolics and flavonoids present in M. sativa. The major compounds detected in M. sativa leaves were protchaechenic acid (3.22%), hydroxyl benzoic acid (1.05%), ?-Phenyl caffate (0.97%) and kaempherol (0.89%). Pterostilbene, a cholesterol-lowering compound, was detected in M. sativa. PMID:25674815

  19. Development of a Fundamental Understanding of Chemical Bonding and Electronic Structure in Spinel Compounds

    SciTech Connect

    Sickafus, K.E.; Wills, J.M.; Chen, S.-P.; Terry, J.H., Jr.; Hartmann, T.; Sheldon, R.I.

    1999-05-14

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos national Laboratory (LANL). Hundreds of ceramic compounds possess the spinel crystal structure and exhibit a remarkable variety of properties, ranging from compounds that are electrical insulators to compounds that are superconducting, or from compounds with ferri- and antiferromagnetic behavior to materials with colossal magnetoresistive characteristics. The unique crystal structure of spinel compounds is in many ways responsible for the widely varying physical properties of spinels. The objective of this project is to investigate the nature of chemical bonding, point defects, and electronic structure in compounds with the spinel crystal structure. Our goal is to understand and predict the stability of the spinel structure as a function of chemical composition, stoichiometry, and cation disorder. The consequences of cation disorder in spinel materials can be profound . The ferromagnetic characteristics of magnesioferrite, for instance, are entirely attributable to disorder on the cation sublattices. Our studies provide insight into the mechanisms of point defect formation and cation disorder and their effects on the electronic band structure and crystal structure of spinel-structure materials. our ultimate objective is to develop a more substantive knowledge of the spinel crystal structure and to promote new and novel uses for spinel compounds. The technical approach to achieve our goals is to combine first-principles calculations with experimental measurements. The structural and electronic properties of spinel samples were experimentally determined primarily with X-ray and neutron scattering, optical and X-ray absorption, and electron energy-loss spectroscopy. Total energy electronic structure calculations were performed to determine structural stability, band structure, density of states, and electron distribution. We also used shell-model total -energy calculations to assess point-defect formation and migration energies in magnesio-aluminate spinel.

  20. Development of a Fundamental Understanding of Chemical Bonding and Electronic Structure in Spinel Compounds

    SciTech Connect

    Sickafus, K.E.; Wills, J.M.; Chen, S.-P.; Terry, J.H., Jr.; Hartmann, T.; Sheldon, R.I.

    1999-06-03

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Hundreds of ceramic compounds possess the spinel crystal structure and exhibit a remarkable variety of properties, ranging from compounds that are electrical insulators to compounds that are superconducting, or from compounds with ferri- and antiferromagnetic behavior to materials with colossal magnetoresistive characteristics. The unique crystal structure of spinel compounds is in many ways responsible for the widely varying physical properties of spinels. The objective of this project is to investigate the nature of chemical bonding, point defects, and electronic structure in compounds with the spinel crystal structure. Our goal is to understand and predict the stability of the spinel structure as a function of chemical composition, stoichiometry, and cation disorder. The consequences of cation disorder in spinel materials can be profound . The ferromagnetic characteristics of magnesioferrite, for instance, are entirely attributable to disorder on the cation sublattices. Our studies provide insight into the mechanisms of point defect formation and cation disorder and their effects on the electronic band structure and crystal structure of spinel-structure materials. Our ultimate objective is to develop a more substantive knowledge of the spinel crystal structure and to promote new and novel uses for spinel compounds. The technical approach to achieve our goals is to combine first-principles calculations with experimental measurements. The structural and electronic properties of spinel samples were experimentally determined primarily with X-ray and neutron scattering, optical and X-ray absorption, and electron energy-loss spectroscopy. Total energy electronic structure calculations were performed to determine structural stability, band structure, density of states, and electron distribution. We also used shell-model total -energy calculations to assess point-defect formation and migration energies in magnesio-aluminate spinel.

  1. FAF-Drugs3: a web server for compound property calculation and chemical library design

    PubMed Central

    Lagorce, David; Sperandio, Olivier; Baell, Jonathan B.; Miteva, Maria A.; Villoutreix, Bruno O.

    2015-01-01

    Drug attrition late in preclinical or clinical development is a serious economic problem in the field of drug discovery. These problems can be linked, in part, to the quality of the compound collections used during the hit generation stage and to the selection of compounds undergoing optimization. Here, we present FAF-Drugs3, a web server that can be used for drug discovery and chemical biology projects to help in preparing compound libraries and to assist decision-making during the hit selection/lead optimization phase. Since it was first described in 2006, FAF-Drugs has been significantly modified. The tool now applies an enhanced structure curation procedure, can filter or analyze molecules with user-defined or eight predefined physicochemical filters as well as with several simple ADMET (absorption, distribution, metabolism, excretion and toxicity) rules. In addition, compounds can be filtered using an updated list of 154 hand-curated structural alerts while Pan Assay Interference compounds (PAINS) and other, generally unwanted groups are also investigated. FAF-Drugs3 offers access to user-friendly html result pages and the possibility to download all computed data. The server requires as input an SDF file of the compounds; it is open to all users and can be accessed without registration at http://fafdrugs3.mti.univ-paris-diderot.fr. PMID:25883137

  2. Micro- and Nanostructured Metal Oxide Chemical Sensors for Volatile Organic Compounds

    NASA Technical Reports Server (NTRS)

    Alim, M. A.; Penn, B. G.; Currie, J. R., Jr.; Batra, A. K.; Aggarwal, M. D.

    2008-01-01

    Aeronautic and space applications warrant the development of chemical sensors which operate in a variety of environments. This technical memorandum incorporates various kinds of chemical sensors and ways to improve their performance. The results of exploratory investigation of the binary composite polycrystalline thick-films such as SnO2-WO3, SnO2-In2O3, SnO2-ZnO for the detection of volatile organic compound (isopropanol) are reported. A short review of the present status of the new types of nanostructured sensors such as nanobelts, nanorods, nanotube, etc. based on metal oxides is presented.

  3. Inclusion compound of vitamin B6 in ?-CD. Physico-chemical and structural investigations

    NASA Astrophysics Data System (ADS)

    Borodi, Gheorghe; Kacso, Irina; Farca?, Sorin I.; Bratu, Ioan

    2009-08-01

    Structural and physico-chemical characterization of supramolecular assembly of vitamin B6 with ?-cyclodextrin (?-CD) prepared by different methods (kneading, co-precipitation and freeze-drying) has been performed by using several spectroscopic techniques (FTIR, 1H NMR, UV-Vis), powder X-ray diffraction and DSC in order to evidence the inclusion compound formation. An analysis of the chemical shifts observed in the 1H-NMR spectra and of the vibrational frequency shifts led to the tentative conclusion that the vitamin B6 probably enters the cyclodextrin torus when forming the ?-CD-vitamin B6 inclusion complex.

  4. 8 - N rule and chemical bonding in main-group MgAgAs-type compounds.

    PubMed

    Bende, David; Wagner, Frank R; Grin, Yuri

    2015-04-20

    The chemical bonding of main-group MgAgAs-type compounds is analyzed with quantum chemical direct-space techniques. A new bonding concept is developed that unites the former ionic bonding and polyanionic network models. Polar and nonpolar contributions to the bonding are extracted by the combined analysis of electron density and electron localizability. A direct-space representation of the 8 - N rule is introduced. In this approach, the anions' heteropolar bonds are treated as a superposition of covalent (nonpolar) and lone-pair closed-shell (polar) contributions. The relation between covalent (nonpolar) and lone-pair (polar) character is obtained with the ELI-D/QTAIM basin intersection technique. This ratio depends on the constituting elements. On basis of this approach, MgAgAs-type compounds are compared with Zintl phases, where covalent bonds and lone pairs are spatially separated. PMID:25836014

  5. An In Silico Approach for Identification of Potential Anti-Mycobacterial Targets of Vasicine and Related Chemical Compounds.

    PubMed

    Chaliha, Amrita Kashyap; Gogoi, Dhrubajyoti; Chetia, Pankaj; Sarma, Diganta; Buragohain, Alak Kumar

    2016-01-01

    Tuberculosis (TB) is known to mankind as one of the most pervasive and persistent of diseases since the early days of civilization. The growing resistance of the causative pathogen Mycobacterium tuberculosis to the standard drug regimen for TB poses further difficulty in its treatment and control. Screening of novel plant-derived compounds with promising anti-tubercular activity has been cited as a prospective route for new anti-tubercular drug discovery and design. Justicia adhatoda L. is a perennial evergreen shrub which is widely mentioned in scientific literature on account of its potent anti-mycobacterial properties. In the present study, we have employed a series of computational methodologies to reveal the probable molecular interactions of vasicine, the principal alkaloid of Justicia adhatoda L., and two of its close natural derivatives- vasicinone and deoxyvasicine, with certain biological targets in M. tuberculosis. Targets were identified from literature and through a reverse Pharmacophore-based approach. Subsequent comparative molecular docking to identify the best ligand-target interactions revealed Antigen 85C of M. tuberculosis as the most potent biological target of vasicine on the basis of optimum molecular docking values. A chemogenomics approach was also employed to validate the molecular interactions between the same class of chemical compounds as vasicine and Antigen 85C. Further, a library of structural analogs of vasicine was created by bioiosterism-based drug design to identify structural analogs with better inhibitory potential against Antigen 85C. PMID:26632438

  6. Real-time monitoring of volatile organic compounds using chemical ionization mass spectrometry

    DOEpatents

    Mowry, Curtis Dale (Albuquerque, NM); Thornberg, Steven Michael (Peralta, NM)

    1999-01-01

    A system for on-line quantitative monitoring of volatile organic compounds (VOCs) includes pressure reduction means for carrying a gaseous sample from a first location to a measuring input location maintained at a low pressure, the system utilizing active feedback to keep both the vapor flow and pressure to a chemical ionization mode mass spectrometer constant. A multiple input manifold for VOC and gas distribution permits a combination of calibration gases or samples to be applied to the spectrometer.

  7. Metal organic chemical vapor deposition of 111-v compounds on silicon

    DOEpatents

    Vernon, Stanley M. (Wellesley, MA)

    1986-01-01

    Expitaxial composite comprising thin films of a Group III-V compound semiconductor such as gallium arsenide (GaAs) or gallium aluminum arsenide (GaAlAs) on single crystal silicon substrates are disclosed. Also disclosed is a process for manufacturing, by chemical deposition from the vapor phase, epitaxial composites as above described, and to semiconductor devices based on such epitaxial composites. The composites have particular utility for use in making light sensitive solid state solar cells.

  8. Selenium status in workers handling aromatic nitro-amino compounds in a chemical factory

    SciTech Connect

    Yoshida, M.; Sunaga, M.; Hara, I. )

    1990-09-01

    The selenium status of workers handling aromatic nitro-amino (ANA) compounds was evaluated by measurement of their blood and urinary selenium concentrations and blood glutathione peroxidase (GSH-Px) activities. Forty-seven healthy Japanese male workers (42.7 +/- 12.1 yr) handling ANA compounds routinely in a chemical factory were studied as exposed workers, and 107 nonindustrial healthy Japanese males (39.3 +/- 10.0 yr) in the same region served as a control group. Urinary diazoreaction-positive metabolites and methemoglobin, both of which have been used as indices of exposure to ANA compounds, were significantly elevated in the exposed workers. Both plasma and erythrocyte selenium in the exposed workers showed 20% lower values compared to the control group. GSH-Px activities in plasma and erythrocytes were also significantly decreased in the exposed workers, but urinary selenium excretions were similar between the two groups. Questionnaire information obtained from each subject regarding intake habits of selenium-rich foods (bread, eggs, meat, and fish) indicated that the average dietary selenium intake was similar for the control group and the exposed workers. These results indicate that (1) the workers handling ANA compounds were surely exposed to these chemicals; (2) their selenium status was lower than that of the nonindustrial controls; and (3) the low selenium status was not associated with any dietary factor.

  9. Crystal chemical and quantum chemical studies of Ba(Sr)-Nb oxide compounds

    NASA Technical Reports Server (NTRS)

    Zubkov, V. G.; Turzhevsky, S. A.; Pereliaev, V. A.; Liechtenstein, A. I.; Gubanov, V. A.

    1990-01-01

    The information available on the BaO(SrO)-NbO-NbO2 system with the niobium atom in the lower oxidation degree is very limited. Very few compounds have been found previously in this system. They are BaNbO3, SrxNbO3(0,7=x=1), Ba2Nb2O9, SrNb8O14; and some suggestions on the BaNb8O14 existence have been made also. At the same time Nb-based oxide compounds could be quite interesting in the search of new noncopper high T(sub c) superconductors Researchers studied Ba(Sr) NbxO2x-2 and Ba2(Sr2)-NbxO2x-1 compositions in the phase diagram of BaO(SrO)-NbO-NbO2 system. The synthesis of the materials was carried out in vacuum at the temperatures of 1000 to 1500 C. Barium carbonate and niobium pentoxide were used as initial components. X-ray analysis was carried out.

  10. Chemical Modification Identifies Two Populations of Glycerophospholipid Flippase in Rat Liver ER

    E-print Network

    Menon, Anant K.

    Chemical Modification Identifies Two Populations of Glycerophospholipid Flippase in Rat Liver ER)1 and bacterial cytoplasmic membrane (bCM). These lipids must be transported across the bilayer-6). The reconstitution experiments also showed that phosphatidylcholine was rapidly exchanged (half-time for exchange 3

  11. USE OF THE RIBONUCLEASE PROTECTION ASSAY FOR IDENTIFYING CHEMICALS WHICH ELLICIT HYPERSENSITIVITY RESPONSES

    EPA Science Inventory

    Use of the Ribonuclease Protection Assay (RPA) for Identifying Chemicals that Elicit Hypersensitivity Responses. L.M. Plitnick, 1, D.M. Sailstad, 2, and R.J. Smialowicz, 2 1UNC, Curriculum in Toxicology, Chapel Hill, NC and 2USEPA, NHEERL, RTP, NC.

    The incidence of aller...

  12. Solvent Extraction of Chemical Attribution Signature Compounds from Painted Wall Board: Final Report

    SciTech Connect

    Wahl, Jon H.; Colburn, Heather A.

    2009-10-29

    This report summarizes work that developed a robust solvent extraction procedure for recovery of chemical attribution signature (CAS) compound dimethyl methyl phosphonate (DMMP) (as well as diethyl methyl phosphonate (DEMP), diethyl methyl phosphonothioate (DEMPT), and diisopropyl methyl phosphonate (DIMP)) from painted wall board (PWB), which was selected previously as the exposed media by the chemical attribution scientific working group (CASWG). An accelerated solvent extraction approach was examined to determine the most effective method of extraction from PWB. Three different solvent systems were examined, which varied in solvent strength and polarity (i.e., 1:1 dichloromethane : acetone,100% methanol, and 1% isopropanol in pentane) with a 1:1 methylene chloride : acetone mixture having the most robust and consistent extraction for four original target organophosphorus compounds. The optimum extraction solvent was determined based on the extraction efficiency of the target analytes from spiked painted wallboard as determined by gas chromatography x gas chromatography mass spectrometry (GCxGC-MS) analysis of the extract. An average extraction efficiency of approximately 60% was obtained for these four compounds. The extraction approach was further demonstrated by extracting and detecting the chemical impurities present in neat DMMP that was vapor-deposited onto painted wallboard tickets.

  13. Miniaturized sequential injection analyzer for the monitoring and quantitation of chemical weapons degradation compounds

    NASA Astrophysics Data System (ADS)

    Lancaster, Herbert L., III; Postlethwaite, Timothy A.; Zhang, Peng; Sorrells, Richard

    2002-06-01

    The ability to monitor and detect chemical warfare agents and their degradation compounds continues to be of utmost importance. Remote on-site field analysis of these compounds is also extremely important as it relates to treaty verification for the Chemical Weapons Convention, as well as the minimization and elimination of human exposure. A portable instrument has been developed and miniaturized that allows for the detection of these compounds in the field with better quantitative results and higher reproducibility than traditional field test kits. All sample and reagent manipulations are conducted in a completely automated fashion. Quantitative results may be determined colorimetrically using the molybdenum blue reaction for the final degradation product of phosphonic acid based chemical warfare agents with a detection limit of 0.05 ppm. The instrument is based on the flow analysis technique of sequential injection analysis (SIA). The benefits of this approach are that the method provides rapid response, high reproducibility of results, high sensitivity and minimal waste production.

  14. A Framework for Identifying Selective Chemical Applications for IPM in Dryland Agriculture

    PubMed Central

    Umina, Paul A.; Jenkins, Sommer; McColl, Stuart; Arthur, Aston; Hoffmann, Ary A.

    2015-01-01

    Shifts to Integrated Pest Management (IPM) in agriculture are assisted by the identification of chemical applications that provide effective control of pests relative to broad-spectrum pesticides but have fewer negative effects on natural enemy (beneficial) groups that assist in pest control. Here, we outline a framework for identifying such applications and apply this framework to field trials involving the crop establishment phase of Australian dryland cropping systems. Several chemicals, which are not presently available to farmers in Australia, were identified as providing moderate levels of pest control and seedling protection, with the potential to be less harmful to beneficial groups including predatory mites, predatory beetles and ants. This framework highlights the challenges involved in chemically controlling pests while maintaining non-target populations when pest species are present at damaging levels. PMID:26694469

  15. A Framework for Identifying Selective Chemical Applications for IPM in Dryland Agriculture.

    PubMed

    Umina, Paul A; Jenkins, Sommer; McColl, Stuart; Arthur, Aston; Hoffmann, Ary A

    2015-01-01

    Shifts to Integrated Pest Management (IPM) in agriculture are assisted by the identification of chemical applications that provide effective control of pests relative to broad-spectrum pesticides but have fewer negative effects on natural enemy (beneficial) groups that assist in pest control. Here, we outline a framework for identifying such applications and apply this framework to field trials involving the crop establishment phase of Australian dryland cropping systems. Several chemicals, which are not presently available to farmers in Australia, were identified as providing moderate levels of pest control and seedling protection, with the potential to be less harmful to beneficial groups including predatory mites, predatory beetles and ants. This framework highlights the challenges involved in chemically controlling pests while maintaining non-target populations when pest species are present at damaging levels. PMID:26694469

  16. Extended Functional Groups (EFG): An Efficient Set for Chemical Characterization and Structure-Activity Relationship Studies of Chemical Compounds.

    PubMed

    Salmina, Elena S; Haider, Norbert; Tetko, Igor V

    2015-01-01

    The article describes a classification system termed "extended functional groups" (EFG), which are an extension of a set previously used by the CheckMol software, that covers in addition heterocyclic compound classes and periodic table groups. The functional groups are defined as SMARTS patterns and are available as part of the ToxAlerts tool (http://ochem.eu/alerts) of the On-line CHEmical database and Modeling (OCHEM) environment platform. The article describes the motivation and the main ideas behind this extension and demonstrates that EFG can be efficiently used to develop and interpret structure-activity relationship models. PMID:26703557

  17. Source and plume investigation of chlorinated compounds in groundwater at a chemical plant

    SciTech Connect

    Trahan, D.B.

    1995-10-01

    A site assessment was conducted to determine the distribution of chlorinated compounds in soil and groundwater at a chemical plant in Geismar, Louisiana. The assessment first included an investigation of the source(S) of the contaminants using aerial photos, interviews and plant records. Next, the stratigraphic framework of the site was defined with a hydrogeological investigation using historic borin logs and cone penetrometer testing (CPT). Finally, a plume investigation was performed to determine the horizontal and vertical extent of the contamination using direct-push methods for sampling of soil and groundwater. It was determined that chlorinated compounds originated from leaking drums and cleaning operations prior to 1975. Downward migration of these compounds may have been promoted by the installation of uncased 50-foot wooden pillings. The contamination is limited both vertical and horizontally, to three hydrogeologic zones: (1) the first water-bearing silt zone; (2) an intermediate zone consisting of interlayered silt and clay; and (3) the second water-bearing silt zone. The concentration of chlorinated compounds are greatest in the intermediate zone. There is some evidence of natural degradation of the chlorinated compounds, particularly in the first water-bearing zone.

  18. Cyanobacteria and microalgae: a renewable source of bioactive compounds and other chemicals.

    PubMed

    Encarnação, Telma; Pais, Alberto A C C; Campos, Maria G; Burrows, Hugh D

    2015-01-01

    Microalgae and cyanobacteria are rich sources of many valuable compounds, including important bioactive and biotechnologically relevant chemicals. Their enormous biodiversity, and the consequent variability in the respective biochemical composition, make microalgae cultivations a promising resource for many novel chemically and biologically active molecules and compounds of high commercial value such as lipids and dyes. The nature of the chemicals produced can be manipulated by changing the cultivation media and conditions. Algae are extremely versatile because they can be adapted to a variety of cell culture conditions. They do not require arable land, can be cultivated on saline water and wastewaters, and require much less water than plants. They possess an extremely high growth rate making these microorganisms very attractive for use in biofuel production--some species of algae can achieve around 100 times more oil than oil seeds. In addition, microalgae and cyanobacteria can accumulate various biotoxins and can contribute to mitigate greenhouse gases since they produce biomass through carbon dioxide fixation. In this review, we provide an overview of the application of microalgae in the production of bioactive and other chemicals. PMID:26288917

  19. Determination of the bioactive compounds, antioxidant activity and chemical composition of Brazilian blackberry, red raspberry, strawberry, blueberry and sweet cherry fruits.

    PubMed

    de Souza, Vanessa Rios; Pereira, Patrícia Aparecida Pimenta; da Silva, Thais Lomônaco Teodoro; de Oliveira Lima, Luiz Carlos; Pio, Rafael; Queiroz, Fabiana

    2014-08-01

    This study aimed to evaluate the chemical composition, identify the bioactive compounds and measure the antioxidant activity present in blackberry, red raspberry, strawberry, sweet cherry and blueberry fruits produced in the subtropical areas of Brazil and to verify that the chemical properties of these fruit are similar when compared to the temperate production zones. Compared with berries and cherries grown in temperate climates, the centesimal composition and physical chemical characteristics found in the Brazilian berries and cherries are in agreement with data from the literature. For the mineral composition, the analyzed fruits presented lower concentrations of P, K, Ca, Mg and Zn and higher levels of Fe. The values found for the bioactive compounds generally fit the ranges reported in the literature with minor differences. The greatest difference was found in relation to ascorbic acid, as all fruits analyzed showed levels well above those found in the literature. PMID:24629981

  20. Compounded bioidentical hormone therapy: identifying use trends and knowledge gaps among US women

    PubMed Central

    Pinkerton, JoAnn V.; Santoro, Nanette

    2015-01-01

    Abstract Objective: Two surveys (Harris and Rose surveys) were conducted to quantify the use of compounded hormone therapy (CHT; or bioidentical hormone therapy) among perimenopausal and postmenopausal women in the United States, to assess women's knowledge of CHT versus Food and Drug Administration (FDA)–approved hormone therapy, and to gather information on menopausal experience. Methods: The Harris survey was administered to 801 women aged 45 to 60 years who had experienced at least one menopausal symptom. The Rose survey was administered to 2,044 women aged 40 years or older who were ever users of hormone therapy. Women were queried about menopausal symptoms, hormone therapy use, and knowledge of CHT. Findings from the Rose survey were extrapolated using US Census Bureau data and prescription claims for FDA-approved hormone therapy to estimate the prevalence of CHT use. Results: According to extrapolations using Rose data, up to 2.5 million US women aged 40 years or older may use CHT annually, accounting for 28% to 68% of hormone therapy prescriptions. Harris data showed that 86% of women surveyed were unaware that CHT products are not FDA-approved. The Rose survey asked a subset of 1,771 women whether their hormone therapy had been personalized based on hormone levels; 21% (378) answered “yes” whereas 27% (476) did not know. In both surveys, most hormone therapy users stated that their physician had recommended the treatment. Conclusions: We estimate that 1 million to 2.5 million US women aged 40 years or older use CHT. The data suggest that many women are unaware that compounded hormones have not been evaluated or approved by the FDA. Providers have an educational opportunity to ensure that women considering hormone therapy understand the risks and benefits of inadequately regulated CHT. PMID:25692877

  1. 76 FR 63304 - Guidance for Industry on Incorporation of Physical-Chemical Identifiers Into Solid Oral Dosage...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-12

    ...DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and...Physical-Chemical Identifiers Into Solid Oral Dosage Form Drug Products for...Physical-Chemical Identifiers Into Solid Oral Dosage Form Drug Products for...identifiers (PCIDs) into solid oral dosage forms (SODFs),...

  2. Design and characterization of chemical space networks for different compound data sets.

    PubMed

    Zwierzyna, Magdalena; Vogt, Martin; Maggiora, Gerald M; Bajorath, Jürgen

    2015-02-01

    Chemical Space Networks (CSNs) are generated for different compound data sets on the basis of pairwise similarity relationships. Such networks are thought to complement and further extend traditional coordinate-based views of chemical space. Our proof-of-concept study focuses on CSNs based upon fingerprint similarity relationships calculated using the conventional Tanimoto similarity metric. The resulting CSNs are characterized with statistical measures from network science and compared in different ways. We show that the homophily principle, which is widely considered in the context of social networks, is a major determinant of the topology of CSNs of bioactive compounds, designed as threshold networks, typically giving rise to community structures. Many properties of CSNs are influenced by numerical features of the conventional Tanimoto similarity metric and largely dominated by the edge density of the networks, which depends on chosen similarity threshold values. However, properties of different CSNs with constant edge density can be directly compared, revealing systematic differences between CSNs generated from randomly collected or bioactive compounds. PMID:25465052

  3. Tankyrase 1 Inhibitors with Drug-like Properties Identified by Screening a DNA-Encoded Chemical Library.

    PubMed

    Samain, Florent; Ekblad, Torun; Mikutis, Gediminas; Zhong, Nan; Zimmermann, Mauro; Nauer, Angela; Bajic, Davor; Decurtins, Willy; Scheuermann, Jörg; Brown, Peter J; Hall, Jonathan; Gräslund, Susanne; Schüler, Herwig; Neri, Dario; Franzini, Raphael M

    2015-06-25

    We describe the synthesis and screening of a DNA-encoded chemical library containing 76230 compounds. In this library, sets of amines and carboxylic acids are directly linked producing encoded compounds with compact structures and drug-like properties. Affinity screening of this library yielded inhibitors of the potential pharmaceutical target tankyrase 1, a poly(ADP-ribose) polymerase. These compounds have drug-like characteristics, and the most potent hit compound (X066/Y469) inhibited tankyrase 1 with an IC50 value of 250 nM. PMID:26061013

  4. Quantum chemical and statistical study of megazol-derived compounds with trypanocidal activity

    NASA Astrophysics Data System (ADS)

    Rosselli, F. P.; Albuquerque, C. N.; da Silva, A. B. F.

    In this work we performed a structure-activity relationship (SAR) study with the aim to correlate molecular properties of the megazol compound and 10 of its analogs with the biological activity against Trypanosoma cruzi (trypanocidal or antichagasic activity) presented by these molecules. The biological activity indication was obtained from in vitro tests and the molecular properties (variables or descriptors) were obtained from the optimized chemical structures by using the PM3 semiempirical method. It was calculated ˜80 molecular properties selected among steric, constitutional, electronic, and lipophilicity properties. In order to reduce dimensionality and investigate which subset of variables (descriptors) would be more effective in classifying the compounds studied, according to their degree of trypanocidal activity, we employed statistical methodologies (pattern recognition and classification techniques) such as principal component analysis (PCA), hierarchical cluster analysis (HCA), K-nearest neighbor (KNN), and discriminant function analysis (DFA). These methods showed that the descriptors molecular mass (MM), energy of the second lowest unoccupied molecular orbital (LUMO+1), charge on the first nitrogen at substituent 2 (qN'), dihedral angles (D1 and D2), bond length between atom C4 and its substituent (L4), Moriguchi octanol-partition coefficient (MLogP), and length-to-breadth ratio (L/Bw) were the variables responsible for the separation between active and inactive compounds against T. cruzi. Afterwards, the PCA, KNN, and DFA models built in this work were used to perform trypanocidal activity predictions for eight new megazol analog compounds.

  5. A Substrate Pharmacophore for the Human Organic Cation/Carnitine Transporter Identifies Compounds Associated with Rhabdomyolysis

    PubMed Central

    Ekins, Sean; Diao, Lei; Polli, James E.

    2012-01-01

    The human Organic Cation/Carnitine Transporter (hOCTN2), is a high affinity cation/carnitine transporter expressed widely in human tissues and is physiologically important for the homeostasis of L-carnitine. The objective of this study was to elucidate the substrate requirements of this transporter via computational modelling based on published in vitro data. Nine published substrates of hOCTN2 were used to create a common features pharmacophore that was validated by mapping other known OCTN2 substrates. The pharmacophore was used to search a drug database and retrieved molecules that were then used as search queries in PubMed for instances of a side effect (rhabdomyolysis) associated with interference with L-carnitine transport. The substrate pharmacophore was comprised of two hydrogen bond acceptors, a positive ionizable feature and ten excluded volumes. The substrate pharmacophore also mapped 6 out of 7 known substrate molecules used as a test set. After searching a database of ~800 known drugs, thirty drugs were predicted to map to the substrate pharmacophore with L-carnitine shape restriction. At least 16 of these molecules had case reports documenting an association with rhabdomyolysis and represent a set for prioritizing for future testing as OCTN2 substrates or inhibitors. This computational OCTN2 substrate pharmacophore derived from published data partially overlaps a previous OCTN2 inhibitor pharmacophore and is also able to select compounds that demonstrate rhabdomyolysis, further confirming the possible linkage between this side effect and hOCTN2. PMID:22339151

  6. Chemicals identified in human biological media: a data base. Third annual report, October 1981

    SciTech Connect

    Cone, M.V.; Baldauf, M.F.; Martin, F.M.

    1981-12-01

    Data from almost 1600 of the 3800 body-burden documents collected to date have been entered in the data base as of October 1981. The emphasis on including recent literature and significant research documents has resulted in a chronological mix of articles from 1974 to the present. When body-burden articles are identified, data are extracted and entered in the data base by chemical and tissue/body fluid. Each data entry comprises a single record (or line entry) and is assigned a record number. If a particular document deals with more than one chemical and/or tissue, there will be multiple records for that document. For example, a study of 5 chemicals in each of 3 tissues has 15 different records (or 15 line entries) in the data base with 15 record numbers. Record numbers are assigned consecutively throughout the entire data base and appear in the upper left corner of the first column for each record.

  7. Biological and chemical investigation of Allium cepa L. response to selenium inorganic compounds.

    PubMed

    Michalska-Kacymirow, M; Kurek, E; Smolis, A; Wierzbicka, M; Bulska, E

    2014-06-01

    The aim of this study was to evaluate the biological and chemical response of Allium cepa L. exposed to inorganic selenium compounds. Besides the investigation of the total content of selenium as well as its chemical speciation, the Allium test was used to evaluate the growth of onion roots and mitotic activity in the roots' meristem. The total content of selenium was determined by inductively coupled plasma mass spectrometry (ICP MS). High-performance liquid chromatography (HPLC), coupled to ICP MS, was used for the selenium chemical speciation. Results indicated that A. cepa plants are able to biotransform inorganic selenium compounds into their organic derivatives, e.g., Se-methylselenocysteine from the Se(IV) inorganic precursor. Although the differences in the biotransformation of selenium are due mainly to the oxidation state of selenium, the experiment has also shown a fine effect of counter ions (H(+), Na(+), NH4 (+)) on the response of plants and on the specific metabolism of selenium. PMID:24652154

  8. Real-time monitoring of volatile organic compounds using chemical ionization mass spectroscopy: Final report

    SciTech Connect

    Thornberg, S.M.; Mowry, C.D.; Keenan, M.R.; Bender, S.F.A.; Owen, T.

    1997-04-01

    Volatile organic compound (VOC) emission to the atmosphere is of great concern to semiconductor manufacturing industries, research laboratories, the public, and regulatory agencies. Some industries are seeking ways to reduce emissions by reducing VOCs at the point of use (or generation). This paper discusses the requirements, design, calibration, and use of a sampling inlet/quadrupole mass spectrometer system for monitoring VOCs in a semiconductor manufacturing production line. The system uses chemical ionization to monitor compounds typically found in the lithography processes used to manufacture semiconductor devices (e.g., acetone, photoresist). The system was designed to be transportable from tool to tool in the production line and to give the operator real-time feedback so the process(es) can be adjusted to minimize VOC emissions. Detection limits ranging from the high ppb range for acetone to the low ppm range fore other lithography chemicals were achieved using chemical ionization mass spectroscopy at a data acquisition rate of approximately 1 mass spectral scan (30 to 200 daltons) per second. A demonstration of exhaust VOC monitoring was performed at a working semiconductor fabrication facility during actual wafer processing.

  9. Revisiting benzene cluster cations for the chemical ionization of dimethyl sulfide and select volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Kim, M. J.; Zoerb, M. C.; Campbell, N. R.; Zimmermann, K. J.; Blomquist, B. W.; Huebert, B. J.; Bertram, T. H.

    2015-10-01

    Benzene cluster cations were revisited as a sensitive and selective reagent ion for the chemical ionization of dimethyl sulfide (DMS) and a select group of volatile organic compounds (VOCs). Laboratory characterization was performed using both a new set of compounds (i.e. DMS, ?-caryophyllene) as well as previously studied VOCs (i.e., isoprene, ?-pinene). Using a field deployable chemical ionization time-of-flight mass spectrometer (CI-ToFMS), benzene cluster cations demonstrated high sensitivity (> 1 ncps ppt-1) to DMS, isoprene, and ?-pinene standards. Parallel measurements conducted using a chemical-ionization quadrupole mass spectrometer, with a weaker electric field, demonstrated that ion-molecule reactions likely proceed through a combination of ligand-switching and direct charge transfer mechanisms. Laboratory tests suggest that benzene cluster cations may be suitable for the selective ionization of sesquiterpenes, where minimal fragmentation (< 25 %) was observed for the detection of ?-caryophyllene, a bicyclic sesquiterpene. The field stability of benzene cluster cations using CI-ToFMS was examined in the marine boundary layer during the High Wind Gas Exchange Study (HiWinGS). The use of benzene cluster cation chemistry for the selective detection of DMS was validated against an atmospheric pressure ionization mass spectrometer. Measurements from the two instruments were highly correlated (R2=0.80) over a wide range of sampling conditions.

  10. Identifying Compounds that Induce Opening of the Mitochondrial Permeability Transition Pore in Isolated Rat Liver Mitochondria.

    PubMed

    Marroquin, Lisa; Swiss, Rachel; Will, Yvonne

    2014-01-01

    The mitochondrial permeability transition pore (MPTP) is a protein pore that forms in the inner mitochondrial membrane and allows the membrane to be permeable to all molecules of less than 1500 Da. Ca(2+) , numerous reactive chemicals, and oxidative stress induce MPTP opening, whereas cyclosporin A (CsA) or bongkrekic acid block it. In addition, several drugs have been shown to induce MPTP opening, leading to the loss of mitochondrial membrane potential, swelling of the matrix because of water accumulation, rupture of the outer mitochondrial membrane, and release of intermembrane space proteins into the cytosol. This ultimately leads to the rupture of the outer mitochondrial membrane and cell demise. Here, we describe an assay using isolated rat liver mitochondria that can detect Ca(2+) -dependent drug-induced opening of the MPTP, providing protocols for screening in both cuvette and 96-well format. Curr. Protoc. Toxicol. 60:25.4.1:-25.4.17. © 2014 by John Wiley & Sons, Inc. PMID:24865648

  11. Laboratory Infrared Spectroscopy to Identify New Compounds on Icy Moon Surfaces

    NASA Astrophysics Data System (ADS)

    Wray, James J.; Young, Cindy L.; Hand, Kevin P.; Poston, Michael J.; Carlson, Robert W.; Clark, Roger N.; Spencer, John R.; Jennings, Donald E.

    2014-11-01

    We are exploring the value of mid-infrared spectroscopy for identifying non-H2O constituents of icy moon surfaces. Recently we reported evidence for a new emissivity feature identified on Iapetus using Cassini’s Composite Infrared Spectrometer [1]. This 11.7 ?m feature is consistent with emissivity minima (transparency features) of very fine-grained silicates. Its position and shape may be diagnostic of silicate type, but most lab data at these wavelengths have been acquired using coarser grains and/or at Earth surface pressures and temperatures. Infrared spectra can change substantially under low-temperature, vacuum conditions [e.g., 2,3].We prepared sieved (<0.4 mm) and very fine-grained (few ?m) powders of six different silicates and measured their VNIR (0.35-2.5 ?m) reflectance spectra under ambient air, and mid-IR (1.2-20 ?m) spectra in a purged N2 glovebox. All silicates exhibited mid-IR transparency features (and loss of other features) in micronized form that were not observed for the coarser grain sizes. Muscovite, a phyllosilicate mineral possibly similar to those tentatively identified on Europa [4], provided the closest match to Iapetus in the mid-IR--although clear VNIR features of muscovite have not been identified on Iapetus [5]--and therefore we measured muscovite across the same wavelength range under Iapetus-like conditions (T=125 K, P<3x10^-8 torr). We will report on our ongoing analysis and plans for additional future measurements in JPL’s Icy Worlds Simulation Lab. [1] Young, C.L., et al. (2014), Workshop on the Habitability of Icy Worlds, Abstract #4038.[2] Logan, L.M., et al. (1973), J. Geophys. Res., 78(23), 4983-5003.[3] Donaldson Hanna, K.L., et al. (2012), J. Geophys. Res., 117, E00H05.[4] Shirley, J.H., et al. (2013), AGU Fall Meeting, Abstract #P54A-07.[5] Clark, R.N., et al. (2012), Icarus, 218, 831-860.

  12. DETERMINATION OF CHEMICAL CLASSES FROM MASS SPECTRA OF TOXIC ORGANIC COMPOUNDS BY SIMCA PATTERN RECOGNITION AND INFORMATION THEORY

    EPA Science Inventory

    The low resolution mass spectra of a set of 78 toxic volatile organic compounds were examined for information concerning chemical classes. These compounds were predominately chloro- and/or bromoaromatics, -alkanes, or -alkenes, which are routinely sought at trace levels in ambien...

  13. Stereoregularity of poly (lactic acid) and their model compounds as studied by NMR and quantum chemical calculations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to understand the origin of the tacticity splitting in the NMR spectrum of poly(lactic acid), monomer model compound and dimer model compounds (both isotactic and syndiotactic) were synthesized and their 1H and 13C NMR chemical shifts observed. Two energetically stable conformations were o...

  14. Predicting physical-chemical properties of compounds from molecular structures by recursive neural networks.

    PubMed

    Bernazzani, Luca; Duce, Celia; Micheli, Alessio; Mollica, Vincenzo; Sperduti, Alessandro; Starita, Antonina; Tiné, Maria Rosaria

    2006-01-01

    In this paper, we report on the potential of a recently developed neural network for structures applied to the prediction of physical chemical properties of compounds. The proposed recursive neural network (RecNN) model is able to directly take as input a structured representation of the molecule and to model a direct and adaptive relationship between the molecular structure and target property. Therefore, it combines in a learning system the flexibility and general advantages of a neural network model with the representational power of a structured domain. As a result, a completely new approach to quantitative structure-activity relationship/quantitative structure-property relationship (QSPR/QSAR) analysis is obtained. An original representation of the molecular structures has been developed accounting for both the occurrence of specific atoms/groups and the topological relationships among them. Gibbs free energy of solvation in water, Delta(solv)G degrees , has been chosen as a benchmark for the model. The different approaches proposed in the literature for the prediction of this property have been reconsidered from a general perspective. The advantages of RecNN as a suitable tool for the automatization of fundamental parts of the QSPR/QSAR analysis have been highlighted. The RecNN model has been applied to the analysis of the Delta(solv)G degrees in water of 138 monofunctional acyclic organic compounds and tested on an external data set of 33 compounds. As a result of the statistical analysis, we obtained, for the predictive accuracy estimated on the test set, correlation coefficient R = 0.9985, standard deviation S = 0.68 kJ mol(-1), and mean absolute error MAE = 0.46 kJ mol(-1). The inherent ability of RecNN to abstract chemical knowledge through the adaptive learning process has been investigated by principal components analysis of the internal representations computed by the network. It has been found that the model recognizes the chemical compounds on the basis of a nontrivial combination of their chemical structure and target property. PMID:16995734

  15. FP Tethering: a screening technique to rapidly identify compounds that disrupt protein-protein interactions

    PubMed Central

    Lodge, Jean M.; Rettenmaier, T. Justin; Wells, James A.; Pomerantz, William C.; Mapp, Anna K.

    2014-01-01

    Tethering is a screening technique for discovering small-molecule fragments that bind to pre-determined sites via formation of a disulphide bond. Tethering screens traditionally rely upon mass spectrometry to detect disulphide bind formation, which requires a time-consuming liquid chromatography step. Here we show that Tethering can be performed rapidly and inexpensively using a homogenous fluorescence polarization (FP) assay that detects displacement of a peptide ligand from the protein target as an indirect readout of disulphide formation. We apply this method, termed FP Tethering, to identify fragments that disrupt the protein-protein interaction between the KIX domain of the transcriptional coactivator CBP and the transcriptional activator peptide pKID. PMID:24795804

  16. Chemical characterization of dissolved organic compounds from coastal sea surface microlayers (Baltic Sea, Germany).

    PubMed

    van Pinxteren, Manuela; Müller, Conny; Iinuma, Yoshiteru; Stolle, Christian; Herrmann, Hartmut

    2012-10-01

    The physicochemical properties of the sea surface microlayer (SML), i.e. the boundary layer between the air and the sea, and its impact on air-sea exchange processes have been investigated for decades. However, a detailed description about these processes remains incomplete. In order to obtain a better chemical characterization of the SML, in a case study three pairs of SML and corresponding bulk water samples were taken in the southern Baltic Sea. The samples were analyzed for dissolved organic carbon and dissolved total nitrogen, as well as for several organic nitrogen containing compounds and carbohydrates, namely aliphatic amines, dissolved free amino acids, dissolved free monosaccharides, sugar alcohols, and monosaccharide anhydrates. Therefore, reasonable analytical procedures with respect to desalting and enrichment were established. All aliphatic amines and the majority of the investigated amino acids (11 out of 18) were found in the samples with average concentrations between 53 ng L(-1) and 1574 ng L(-1). The concentrations of carbohydrates were slightly higher, averaging 2900 ng L(-1). Calculation of the enrichment factor (EF) between the sea surface microlayer and the bulk water showed that dissolved total nitrogen was more enriched (EF: 1.1 and 1.2) in the SML than dissolved organic carbon (EF: 1.0 and 1.1). The nitrogen containing organic compounds were generally found to be enriched in the SML (EF: 1.9-9.2), whereas dissolved carbohydrates were not enriched or even depleted (EF: 0.7-1.2). Although the investigated compounds contributed on average only 0.3% to the dissolved organic carbon and 0.4% to the total dissolved nitrogen fraction, these results underline the importance of single compound analysis to determine SML structure, function, and its potential for a transfer of compounds into the atmosphere. PMID:22475414

  17. A novel 3D high-content assay identifies compounds that prevent fibroblast invasion into tissue surrogates.

    PubMed

    Wenzel, Carsten; Otto, Saskia; Prechtl, Stefan; Parczyk, Karsten; Steigemann, Patrick

    2015-11-15

    Invasion processes underlie or accompany several pathological processes but only a limited number of high-throughput capable phenotypic models exist to test anti-invasive compounds in vitro. We here evaluated 3D co-cultures as a high-content phenotypic screening system for fibrotic invasive processes. 3D multicellular spheroids were used as living tissue surrogates in co-culture with fluorescently labeled lung fibroblasts to monitor invasion processes by automated microscopy. This setup was used to screen a compound library containing 480 known bioactive substances. Identified hits prevented fibroblast invasion and could be subdivided into two hit classes. First, Prostaglandins were shown to prevent fibroblast invasion, most likely mediated by the prostaglandin EP2 receptor and generation of cAMP. Additionally, Rho-associated protein kinase (ROCK) inhibitors prevented fibroblast invasion, possibly by inactivation of myosin II. Importantly, both Prostaglandins and ROCK inhibitors are potential treatment options shown to be effective in in vitro and in vivo models of fibrotic diseases. This validates the presented novel phenotypic screening approach for the evaluation of potential inhibitors and the identification of novel compounds with activity in diseases that are associated with fibroblast invasion. PMID:26475730

  18. PINS chemical identification software

    DOEpatents

    Caffrey, Augustine J.; Krebs, Kennth M.

    2004-09-14

    An apparatus and method for identifying a chemical compound. A neutron source delivers neutrons into the chemical compound. The nuclei of chemical elements constituting the chemical compound emit gamma rays upon interaction with the neutrons. The gamma rays are characteristic of the chemical elements constituting the chemical compound. A spectrum of the gamma rays is generated having a detection count and an energy scale. The energy scale is calibrated by comparing peaks in the spectrum to energies of pre-selected chemical elements in the spectrum. A least-squares fit completes the calibration. The chemical elements constituting the chemical compound can be readily determined, which then allows for identification of the chemical compound.

  19. Chemical Shifts to Metabolic Pathways: Identifying Metabolic Pathways Directly from a Single 2D NMR Spectrum.

    PubMed

    Dubey, Abhinav; Rangarajan, Annapoorni; Pal, Debnath; Atreya, Hanudatta S

    2015-12-15

    Identifying cellular processes in terms of metabolic pathways is one of the avowed goals of metabolomics studies. Currently, this is done after relevant metabolites are identified to allow their mapping onto specific pathways. This task is daunting due to the complex nature of cellular processes and the difficulty in establishing the identity of individual metabolites. We propose here a new method: ChemSMP (Chemical Shifts to Metabolic Pathways), which facilitates rapid analysis by identifying the active metabolic pathways directly from chemical shifts obtained from a single two-dimensional (2D) [(13)C-(1)H] correlation NMR spectrum without the need for identification and assignment of individual metabolites. ChemSMP uses a novel indexing and scoring system comprised of a "uniqueness score" and a "coverage score". Our method is demonstrated on metabolic pathways data from the Small Molecule Pathway Database (SMPDB) and chemical shifts from the Human Metabolome Database (HMDB). Benchmarks show that ChemSMP has a positive prediction rate of >90% in the presence of decluttered data and can sustain the same at 60-70% even in the presence of noise, such as deletions of peaks and chemical shift deviations. The method tested on NMR data acquired for a mixture of 20 amino acids shows a success rate of 93% in correct recovery of pathways. When used on data obtained from the cell lysate of an unexplored oncogenic cell line, it revealed active metabolic pathways responsible for regulating energy homeostasis of cancer cells. Our unique tool is thus expected to significantly enhance analysis of NMR-based metabolomics data by reducing existing impediments. PMID:26556218

  20. Chemical compound of a snow cover in taiga zone territory of the European northeast of Russia

    NASA Astrophysics Data System (ADS)

    Mariya, Vasilevich

    2013-04-01

    Receipt of substances from atmosphere plays an important role in geochemical balance of ecosystems. Atmosphere participates participate in an exchange and substance redistribution for the Earth, and its chemical compound gives the objective information on quality of the air environment. The snow cover acts as the effective store of substances which remain in it in an invariable condition within winter. Chemical compound of snow reflects the valid size of dry both damp losses and quantitative parametres of pollution of ecosystems. Sensitivity of a snow cover to change of industrial conditions in region allows to estimate a state of environment objectively. Distinction of areas on natural receipt macro- and microcomponents from atmosphere causes of an estimation of their background receipt on spreading surface. The purpose of the present work is studying of a chemical compound of a snow cover and spatial distribution of macrocomponents to a taiga zone territories of the European northeast (Republic Komi). It is established that average value of a mineralization of thawed snow, has made 2.8 mg/dm3 and tends to reduction with width increase. Our results have shown that thawed snow water in a taiga zone is characterised by subacidic reaction. Average value ?? has made 4.7 ± 0.1. The oxidation of snow cover is observed from the north on the south. Formation of acidity of a snow cover estimated through the relation of the sum of concentration anions (A = [SO42-] + [N?3-] + [?l-]) to the sum of cations concentration (K = [NH4+] + [Ca2+] + [Mg2+] + [Na+] + [K+]). The received data follows that thawed snow of a taiga zone is characterised by values ?/? <1 at increase in the given relation from the south on the north from 0.42 till (average value equally 0.58). Thus, the acid-base properties of a taiga zone snow cover are defined by deficiency of neutralised connections and prevalence in thawed snow of ions of hydrogen that corresponds to the general situation in the European territory of Russia. Differentiation in distribution macro- and microcomponents in snow from the south on the north is observed statistically authentic latitude: the total maintenance of cations increases in and reduction of anions. The raised receipt of substances is characteristic for southwest and east borders of the investigated territory. Atmospheric precipitation plays an important role in receipt of the basic biogenic substances on a taiga zone territory. Accumulation of organic carbon makes 20 % from the general module of substances. Share reduction of carbon and the general nitrogen in a snow cover from the south on the north is noted. Formation of a snow cover chemical compound of a taiga zone background territories occurs, mainly, at the expense of soluble connections of elements. Factors of enrichment by elements of soluble fraction much more, than for fraction fixed connections also are close to values of accumulation factors of atmospheric aerosol. Chemical compound of snow cover of a taiga zone background territories is formed mainly at the expense of distant carryings over, influence of local sources is slightly. The cartographical basis of spatial distribution of chemical components in a snow cover is created.

  1. Development of a screening assay to identify teratogenic and embryotoxic chemicals using the zebrafish embryo.

    PubMed

    Selderslaghs, Ingrid W T; Van Rompay, An R; De Coen, Wim; Witters, Hilda E

    2009-11-01

    We developed and optimized a screening procedure, in which zebrafish embryos were explored as a model for the evaluation of the specific embryotoxic and teratogenic potential of chemicals. A selection of known positive (retinoic acid, valproic acid, caffeine, lithium chloride) and negative (glucose, saccharin) compounds for developmental toxicity were used to evaluate this method. We exposed embryos and evaluated embryotoxicity and morphological characteristics of the embryos at 24, 48, 72 and 144 h post fertilization. After evaluation of the induced effects, concentration-response curves were created for both embryotoxicity and teratogenic effects. Values for teratogenic indices (TI) were calculated as the ratio LC(50)/EC(50). The results obtained were compared to existing data from studies with laboratory animals and humans. We demonstrated that our classification of the compounds, based on TI values, allows to distinguish teratogens from non-teratogens and supports the application of zebrafish embryos as an alternative method for developmental toxicity studies to predict effects in mammals. PMID:19447169

  2. [Source profile and chemical reactivity of volatile organic compounds from vehicle exhaust].

    PubMed

    Qiao, Yue-Zhen; Wang, Hong-Li; Huang, Cheng; Chen, Chang-Hong; Su, Lei-Yan; Zhou, Min; Xu, Hua; Zhang, Gang-Feng; Chen, Yi-Ran; Li, Li; Chen, Ming-Hua; Huang, Hai-Ying

    2012-04-01

    Light-duty gasoline taxis (LDGT) and passenger cars (LDGV), heavy-duty diesel buses (HDDB) and trucks (HDDT), gasoline motorcycles (MC) and LPG scooters (LPGS), were selected for tailpipe volatile organic compounds (VOCs) samplings by using transient dynamometer and on road test combined with SUMMA canisters technology. The samples were tested by GC-MS to analyze the concentration and species composition of VOCs. The results indicate that light-duty gasoline automobiles have higher fractions of aromatic hydrocarbons, which account for 43.38%-44.45% of the total VOCs, the main aromatic hydrocarbons are toluene and xylenes. Heavy-duty diesel vehicles have higher fractions of alkanes, which constitute 46.86%-48.57% of the total VOCs, the main alkanes are propane, n-dodecane and n-undecane. In addition, oxy-organics account for 13.28%-15.01% of the VOCs, the main oxy-organics is acetone. The major compound from MC and LPGS exhaust is acetylene, it accounts for 39.75% and 76.67% of the total VOCs, respectively. VOCs exhaust from gasoline motorcycles and light-duty gasoline automobiles has a significantly higher chemical reactivity than those from heavy-duty diesel vehicles, which contribute 55% and 44% to the atmospheric chemical reactivity in Shanghai. The gasoline motorcycles and light-duty gasoline automobiles are the key pollution sources affecting city and region ambient oxidation, and the key active species of toluene, xylenes, propylene, and styrene make the greatest contribution. PMID:22720548

  3. Passive Sampling in Regulatory Chemical Monitoring of Nonpolar Organic Compounds in the Aquatic Environment.

    PubMed

    Booij, Kees; Robinson, Craig D; Burgess, Robert M; Mayer, Philipp; Roberts, Cindy A; Ahrens, Lutz; Allan, Ian J; Brant, Jan; Jones, Lisa; Kraus, Uta R; Larsen, Martin M; Lepom, Peter; Petersen, Jördis; Pröfrock, Daniel; Roose, Patrick; Schäfer, Sabine; Smedes, Foppe; Tixier, Céline; Vorkamp, Katrin; Whitehouse, Paul

    2016-01-01

    We reviewed compliance monitoring requirements in the European Union, the United States, and the Oslo-Paris Convention for the protection of the marine environment of the North-East Atlantic, and evaluated if these are met by passive sampling methods for nonpolar compounds. The strengths and shortcomings of passive sampling are assessed for water, sediments, and biota. Passive water sampling is a suitable technique for measuring concentrations of freely dissolved compounds. This method yields results that are incompatible with the EU's quality standard definition in terms of total concentrations in water, but this definition has little scientific basis. Insufficient quality control is a present weakness of passive sampling in water. Laboratory performance studies and the development of standardized methods are needed to improve data quality and to encourage the use of passive sampling by commercial laboratories and monitoring agencies. Successful prediction of bioaccumulation based on passive sampling is well documented for organisms at the lower trophic levels, but requires more research for higher levels. Despite the existence of several knowledge gaps, passive sampling presently is the best available technology for chemical monitoring of nonpolar organic compounds. Key issues to be addressed by scientists and environmental managers are outlined. PMID:26619247

  4. Chemical kinetic study of the oxidation of toluene and related cyclic compounds

    SciTech Connect

    Mehl, M; Frassoldati, A; Fietzek, R; Faravelli, T; Pitz, W; Ranzi, E

    2009-10-01

    Chemical kinetic models of hydrocarbons found in transportation fuels are needed to simulate combustion in engines and to improve engine performance. The study of the combustion of practical fuels, however, has to deal with their complex compositions, which generally involve hundreds of compounds. To provide a simplified approach for practical fuels, surrogate fuels including few relevant components are used instead of including all components. Among those components, toluene, the simplest of the alkyl benzenes, is one of the most prevalent aromatic compounds in gasoline in the U.S. (up to 30%) and is a promising candidate for formulating gasoline surrogates. Unfortunately, even though the combustion of aromatics been studied for a long time, the oxidation processes relevant to this class of compounds are still matter of discussion. In this work, the combustion of toluene is systematically approached through the analysis of the kinetics of some important intermediates contained in its kinetic submechanism. After discussing the combustion chemistry of cyclopentadiene, benzene, phenol and, finally, of toluene, the model is validated against literature experimental data over a wide range of operating conditions.

  5. Advances in SXFA-coated SAW chemical sensors for organophosphorous compound detection.

    PubMed

    Wang, Wen; He, Shitang; Li, Shunzhou; Liu, Minghua; Pan, Yong

    2011-01-01

    A polymer-coated surface acoustic wave (SAW)-based chemical sensor for organophosphorous compound sensing at extremely low concentrations was developed, in which a dual-delay-line oscillator coated with fluoroalcoholpolysiloxane (SXFA) acted as the sensor element. Response mechanism analysis was performed on the SXFA-coated chemical sensor, resulting in the optimal design parameters. The shear modulus of the SXFA, which is the key parameter for theoretical simulation, was extracted experimentally. New designs were done on the SAW devices to decrease the insertion loss. Referring to the new phase modulation approach, superior short-term frequency stability (±2 Hz in seconds) was achieved from the SAW oscillator using the fabricated 300 MHz delay line as the feedback element. In the sensor experiment on dimethylmethylphosphonate (DMMP) detection, the fabricated SXFA-coated chemical sensor exhibited an excellent threshold detection limit up to 0.004 mg/m(3) (0.7 ppb) and good sensitivity (?485 Hz/mg/m(3) for a DMMP concentration of 2?14 mg/m(3)). PMID:22319366

  6. Portable sequential injection analyzer for onsite screening for chemical weapons degradation compounds

    NASA Astrophysics Data System (ADS)

    Postlethwaite, Timothy A.; Zhang, Peng; Lancaster, Herbert L., III; Bacon, Christina P.; Mensch, David

    2002-02-01

    In many circumstances, the ability to perform on-site, point-of-collection analysis can play a pivotal role in the goals or requirements of the inquiry. Toward this end, the use of commercial or customized kits, which require the analyst to manually perform the metering and mixing of reagents with the sample and the subsequent visual, spectrophotometric or other interpretation of the results, has become widespread. Often, these methods can suffer from poor reproducibility and sensitivity in addition to being tedious and time consuming. Flow analysis methods, such as traditional flow injection analysis (FIA) and the more recent sequential injection analysis (SIA), have found widespread use in the automation of sample and reagent handling and subsequent analysis for many important analytes. These methods can be completely automated and offer excellent reproducibility, minimized analysis time, and in certain configurations, very high sensitivity. We have developed a miniaturized, fully portable SIA-based instrument for on-site screening for chemical weapons degradation products during challenge inspections under the Chemical Weapons Convention, as well as for the sensitive analysis of other important environmental analytes. In this paper, we will discuss our portable SIA design, the analytical approaches utilized, and results obtained for the analysis of representative chemical weapons degradation compounds.

  7. An Automated High-Throughput Cell-Based Multiplexed Flow Cytometry Assay to Identify Novel Compounds to Target Candida albicans Virulence-Related Proteins

    PubMed Central

    Bernardo, Stella M.; Allen, Christopher P.; Waller, Anna; Young, Susan M.; Oprea, Tudor; Sklar, Larry A.; Lee, Samuel A.

    2014-01-01

    Although three major classes of systemic antifungal agents are clinically available, each is characterized by important limitations. Thus, there has been considerable ongoing effort to develop novel and repurposed agents for the therapy of invasive fungal infections. In an effort to address these needs, we developed a novel high-throughput, multiplexed screening method that utilizes small molecules to probe candidate drug targets in the opportunistic fungal pathogen Candida albicans. This method is amenable to high-throughput automated screening and is based upon detection of changes in GFP levels of individually tagged target proteins. We first selected four GFP-tagged membrane-bound proteins associated with virulence or antifungal drug resistance in C. albicans. We demonstrated proof-of-principle that modulation of fluorescence intensity can be used to assay the expression of specific GFP-tagged target proteins to inhibitors (and inducers), and this change is measurable within the HyperCyt automated flow cytometry sampling system. Next, we generated a multiplex of differentially color-coded C. albicans strains bearing C-terminal GFP-tags of each gene encoding candidate drug targets incubated in the presence of small molecules from the Prestwick Chemical Library in 384-well microtiter plate format. Following incubation, cells were sampled through the HyperCyt system and modulation of protein levels, as indicated by changes in GFP-levels of each strain, was used to identify compounds of interest. The hit rate for both inducers and inhibitors identified in the primary screen did not exceed 1% of the total number of compounds in the small-molecule library that was probed, as would be expected from a robust target-specific, high-throughput screening campaign. Secondary assays for virulence characteristics based on null mutant strains were then used to further validate specificity. In all, this study presents a method for the identification and verification of new antifungal drugs targeted to fungal virulence proteins using C. albicans as a model fungal pathogen. PMID:25350399

  8. Screening and prioritisation of chemical risks from metal mining operations, identifying exposure media of concern.

    PubMed

    Pan, Jilang; Oates, Christopher J; Ihlenfeld, Christian; Plant, Jane A; Voulvoulis, Nikolaos

    2010-04-01

    Metals have been central to the development of human civilisation from the Bronze Age to modern times, although in the past, metal mining and smelting have been the cause of serious environmental pollution with the potential to harm human health. Despite problems from artisanal mining in some developing countries, modern mining to Western standards now uses the best available mining technology combined with environmental monitoring, mitigation and remediation measures to limit emissions to the environment. This paper develops risk screening and prioritisation methods previously used for contaminated land on military and civilian sites and engineering systems for the analysis and prioritisation of chemical risks from modern metal mining operations. It uses hierarchical holographic modelling and multi-criteria decision making to analyse and prioritise the risks from potentially hazardous inorganic chemical substances released by mining operations. A case study of an active platinum group metals mine in South Africa is used to demonstrate the potential of the method. This risk-based methodology for identifying, filtering and ranking mining-related environmental and human health risks can be used to identify exposure media of greatest concern to inform risk management. It also provides a practical decision-making tool for mine acquisition and helps to communicate risk to all members of mining operation teams. PMID:19353294

  9. An FTIR point sensor for identifying chemical WMD and hazardous materials

    NASA Astrophysics Data System (ADS)

    Norman, Mark L.; Gagnon, Aaron M.; Reffner, John A.; Schiering, David W.; Allen, Jeffrey D.

    2004-03-01

    A new point sensor for identifying chemical weapons of mass destruction and other hazardous materials based on Fourier transform infrared (FT-IR) spectroscopy is presented. The sensor is a portable, fully functional FT-IR system that features a miniaturized Michelson interferometer, an integrated diamond attenuated total reflection (ATR) sample interface, and an embedded on-board computer. Samples are identified by an automated search algorithm that compares their infrared spectra to digitized databases that include reference spectra of nerve and blister agents, toxic industrial chemicals, and other hazardous materials. The hardware and software are designed for use by technicians with no background in infrared spectroscopy. The unit, which is fully self-contained, can be hand-carried and used in a hot zone by personnel in Level A protective gear, and subsequently decontaminated by spraying or immersion. Wireless control by a remote computer is also possible. Details of the system design and performance, including results of field validation tests, are discussed.

  10. Relativistic DFT Calculation of (119)Sn Chemical Shifts and Coupling Constants in Tin Compounds.

    PubMed

    Bagno, Alessandro; Casella, Girolamo; Saielli, Giacomo

    2006-01-01

    The nuclear shielding and spin-spin coupling constants of (119)Sn in stannane, tetramethylstannane, methyltin halides Me4-nSnXn (X = Cl, Br, I; n = 1-3), tin halides, and some stannyl cations have been investigated computationally by DFT methods and Slater all-electron basis sets, including relativistic effects by means of the zeroth order regular approximation (ZORA) method up to spin-orbit coupling. Calculated (119)Sn chemical shifts generally correlate well with experimental values, except when several heavy halogen atoms, especially iodine, are bound to tin. In such cases, calculated chemical shifts are almost constant at the scalar (spin-free) ZORA level; only at the spin-orbit level is a good correlation, which holds for all compounds examined, attained. A remarkable "heavy-atom effect", analogous to that observed for analogous alkyl halides, is evident. The chemical shift of the putative stannyl cation (SnH3(+)) has also been examined, and it is concluded that the spectrum of the species obtained in superacids is inconsistent with a simple SnH3(+) structure; strong coordination to even weak nucleophiles such as FSO3H leads to a very satisfactory agreement. On the contrary, the calculated (119)Sn chemical shift of the trimesitylstannyl cation is in very good agreement with the experimental value. Coupling constants between (119)Sn and halogen nuclei are also well-modeled in general (taking into account the large uncertainties in the experimental values); relativistic spin-orbit effects are again quite evident. Couplings to (13)C and (1)H also fall, on the average, on the same correlation line, but individual values show a significant deviation from the expected unit slope. PMID:26626377

  11. Can Coffee Chemical Compounds and Insecticidal Plants Be Harnessed for Control of Major Coffee Pests?

    PubMed

    Green, Paul W C; Davis, Aaron P; Cossé, Allard A; Vega, Fernando E

    2015-11-01

    Pests and pathogens threaten coffee production worldwide and are difficult to control using conventional methods, such as insecticides. We review the literature on the chemistry of coffee, concentrating on compounds most commonly reported from Coffea arabica and Coffea canephora. Differences in chemistry can distinguish coffee species and varieties, and plants grown under different biogeographic conditions exhibit different chemotypes. A number of chemical groups, such as alkaloids and caffeoylquinic acids, are known to be insecticidal, but most studies have investigated their effects on coffee quality and flavor. More research is required to bridge this gap in knowledge, so that coffee can be bred to be more resistant to pests. Furthermore, we report on some pesticidal plants that have been used for control of coffee pests. Locally sourced pesticidal plants have been underutilized and offer a sustainable alternative to conventional insecticides and could be used to augment breeding for resilience of coffee plants. PMID:26458882

  12. Big Data in Chemical Toxicity Research: The Use of High-Throughput Screening Assays To Identify Potential Toxicants

    PubMed Central

    2015-01-01

    High-throughput screening (HTS) assays that measure the in vitro toxicity of environmental compounds have been widely applied as an alternative to in vivo animal tests of chemical toxicity. Current HTS studies provide the community with rich toxicology information that has the potential to be integrated into toxicity research. The available in vitro toxicity data is updated daily in structured formats (e.g., deposited into PubChem and other data-sharing web portals) or in an unstructured way (papers, laboratory reports, toxicity Web site updates, etc.). The information derived from the current toxicity data is so large and complex that it becomes difficult to process using available database management tools or traditional data processing applications. For this reason, it is necessary to develop a big data approach when conducting modern chemical toxicity research. In vitro data for a compound, obtained from meaningful bioassays, can be viewed as a response profile that gives detailed information about the compound’s ability to affect relevant biological proteins/receptors. This information is critical for the evaluation of complex bioactivities (e.g., animal toxicities) and grows rapidly as big data in toxicology communities. This review focuses mainly on the existing structured in vitro data (e.g., PubChem data sets) as response profiles for compounds of environmental interest (e.g., potential human/animal toxicants). Potential modeling and mining tools to use the current big data pool in chemical toxicity research are also described. PMID:25195622

  13. A Yeast-Based Chemical Screen Identifies a PDE Inhibitor That Elevates Steroidogenesis in Mouse Leydig Cells via PDE8 and PDE4 Inhibition

    PubMed Central

    Demirbas, Didem; Wyman, Arlene R.; Shimizu-Albergine, Masami; Cakici, Ozgur; Beavo, Joseph A.; Hoffman, Charles S.

    2013-01-01

    A cell-based high-throughput screen (HTS) was developed to detect phosphodiesterase 8 (PDE8) and PDE4/8 combination inhibitors. By replacing the Schizosaccharomyces pombe PDE gene with the murine PDE8A1 gene in strains lacking adenylyl cyclase, we generated strains whose protein kinase A (PKA)-stimulated growth in 5-fluoro orotic acid (5FOA) medium reflects PDE8 activity. From our previously-identified PDE4 and PDE7 inhibitors, we identified a PDE4/8 inhibitor that allowed us to optimize screening conditions. Of 222,711 compounds screened, ?0.2% displayed composite Z scores of >20. Additional yeast-based assays using the most effective 367 compounds identified 30 candidates for further characterization. Among these, compound BC8-15 displayed the lowest IC50 value for both PDE4 and PDE8 inhibition in in vitro enzyme assays. This compound also displays significant activity against PDE10A and PDE11A. BC8-15 elevates steroidogenesis in mouse Leydig cells as a single pharmacological agent. Assays using BC8-15 and two structural derivatives support a model in which PDE8 is a primary regulator of testosterone production by Leydig cells, with an additional role for PDE4 in this process. BC8-15, BC8-15A, and BC8-15C, which are commercially available compounds, display distinct patterns of activity against PDE4, PDE8, PDE10A, and PDE11A, representing a chemical toolkit that could be used to examine the biological roles of these enzymes in cell culture systems. PMID:23967182

  14. Clinical breath analysis: Discriminating between human endogenous compounds and exogenous (environmental) chemical confounders

    EPA Science Inventory

    Volatile organic compounds (VOCs) in exhaled breath originate from current or previous environmental exposures (exogenous compounds) and internal metabolic anabolic and catabolic) production (endogenous compounds). The origins of certain VOCs in breath presumed to be endogenous ...

  15. DESI-MS/MS of Chemical Warfare Agents and Related Compounds

    NASA Astrophysics Data System (ADS)

    D'Agostino, Paul A.

    Solid phase microextraction (SPME) fibers were used to headspace ­sample chemical warfare agents and their hydrolysis products from glass vials and glass vials containing spiked media, including Dacron swabs, office carpet, paper and fabric. The interface of the Z-spray source was modified to permit safe introduction of the SPME fibers for desorption electrospray ionization mass spectrometric (DESI-MS) analysis. A "dip and shoot" method was also developed for the rapid sampling and DESI-MS analysis of chemical warfare agents and their hydrolysis products in liquid samples. Sampling was performed by simply dipping fused silica, stainless steel or SPME tips into the organic or aqueous samples. Replicate analyses were completed within several minutes under ambient conditions with no sample pre-treatment, resulting in a significant increase in sample throughput. The developed sample handling and analysis method was applied to the determination of chemical warfare agent content in samples containing unknown chemical and/or biological warfare agents. Ottawa sand was spiked with sulfur mustard, extracted with water and autoclaved to ensure sterility. Sulfur mustard was completely hydrolysed during the extraction/autoclave step and thiodiglycol was identified by DESI-MS, with analyses generally being completed within 1 min using the "dip and shoot" method.

  16. A simple and predictive phenotypic High Content Imaging assay for Plasmodium falciparum mature gametocytes to identify malaria transmission blocking compounds

    PubMed Central

    Lucantoni, Leonardo; Silvestrini, Francesco; Signore, Michele; Siciliano, Giulia; Eldering, Maarten; Dechering, Koen J.; Avery, Vicky M.; Alano, Pietro

    2015-01-01

    Plasmodium falciparum gametocytes, specifically the mature stages, are the only malaria parasite stage in humans transmissible to the mosquito vector. Anti-malarial drugs capable of killing these forms are considered essential for the eradication of malaria and tools allowing the screening of large compound libraries with high predictive power are needed to identify new candidates. As gametocytes are not a replicative stage it is difficult to apply the same drug screening methods used for asexual stages. Here we propose an assay, based on high content imaging, combining “classic” gametocyte viability readout based on gametocyte counts with a functional viability readout, based on gametocyte activation and the discrimination of the typical gamete spherical morphology. This simple and rapid assay has been miniaturized to a 384-well format using acridine orange staining of wild type P. falciparum 3D7A sexual forms, and was validated by screening reference antimalarial drugs and the MMV Malaria Box. The assay demonstrated excellent robustness and ability to identify quality hits with high likelihood of confirmation of transmission reducing activity in subsequent mosquito membrane feeding assays. PMID:26553647

  17. Safety in the Chemical Laboratory: Nitric Acid, Nitrates, and Nitro Compounds.

    ERIC Educational Resources Information Center

    Bretherick, Leslie

    1989-01-01

    Discussed are the potential hazards associated with nitric acid, inorganic and organic nitrate salts, alkyl nitrates, acyl nitrates, aliphatic nitro compounds, aromatic nitro compounds, and nitration reactions. (CW)

  18. Overview of toxicity data and risk assessment methods for evaluating the chemical effects of depleted uranium compounds.

    SciTech Connect

    Hartmann, H. M.; Monette, F. A.; Avci, H. I.; Environmental Assessment

    2000-10-01

    In the United States, depleted uranium is handled or used in several chemical forms by both governmental agencies and private industry (primarily companies producing and machining depleted uranium metal for military applications). Human exposure can occur as a result of handling these compounds, routine low-level effluent releases to the environment from processing facilities, or materials being accidentally released from storage locations or during processing or transportation. Exposure to uranium can result in both chemical and radiological toxicity, but in most instances chemical toxicity is of greater concern. This article discusses the chemical toxic effects from human exposure to depleted uranium compounds that are likely to be handled during the long-term management and use of depleted uranium hexafluoride (UF{sub 6}) inventories in the United States. It also reviews representative publications in the toxicological literature to establish appropriate reference values for risk assessments. Methods are described for evaluating chemical toxicity caused by chronic low-level exposure and acute exposure. Example risk evaluations are provided for illustration. Preliminary results indicate that chemical effects of chronic exposure to uranium compounds under normal operating conditions would be negligibly small. Results also show that acute exposures under certain accident conditions could cause adverse chemical effects among the populations exposed.

  19. Development of a Wireless and Passive SAW-Based Chemical Sensor for Organophosphorous Compound Detection.

    PubMed

    Xu, Fang-Qian; Wang, Wen; Xue, Xu-Feng; Hu, Hao-Liang; Liu, Xin-Lu; Pan, Yong

    2015-01-01

    A new wireless and passive surface acoustic wave (SAW)-based chemical sensor for organophosphorous compound (OC) detection is presented. A 434 MHz reflective delay line configuration composed by single phase unidirectional transducers (SPUDTs) and three shorted reflectors was fabricated on YZ LiNbO? piezoelectric substrate as the sensor element. A thin fluoroalcoholpolysiloxane (SXFA) film acted as the sensitive interface deposited onto the SAW propagation path between the second and last reflectors of the SAW device. The first reflector was used for the temperature compensation utilizing the difference method. The adsorption between the SXFA and OC molecules modulates the SAW propagation, especially for the time delay of the SAW, hence, the phase shifts of the reflection peaks from the corresponding reflectors can be used to characterize the target OC. Prior to the sensor fabrication, the coupling of modes (COM) and perturbation theory were utilized to predict the SAW device performance and the gas adsorption. Referring to a frequency-modulated continuous wave (FMCW)-based reader unit, the developed SAW chemical sensor was wirelessly characterized in gas exposure experiments for dimethylmethylphosphonate (DMMP) detection. Sensor performance parameters such as phase sensitivity, repeatability, linearity, and temperature compensation were evaluated experimentally. PMID:26633419

  20. ION COMPOSITION ELUCIDATION (ICE): A HIGH RESOLUTION MASS SPECTROMETRIC TOOL FOR IDENTIFYING ORGANIC COMPOUNDS IN COMPLEX EXTRACTS OF ENVIRONMENTAL SAMPLES

    EPA Science Inventory


    Unidentified Organic Compounds. For target analytes, standards are purchased, extraction and clean-up procedures are optimized, and mass spectra and retention times for the chromatographic separation are obtained for comparison to the target compounds in environmental sample ...

  1. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    SciTech Connect

    Apel, E.; Springston, S.; Karl, T.; Emmons, L.; Flocke, F.; Hills, A. J.; Madronich, S.; Lee-Taylor, J.; Fried, A.; Weibring, P.; Walega, J.; Richter, D., Tie, X.; Mauldin, L.; Campos, T.; Sive, B.; Kleinman, L.; Springston, S., Zaveri, R.; deGouw, J.; Zheng, J.; Zhang, R.; Rudolph, J.; Junkermann, W.; Riemer, D. D.

    2009-11-01

    The volatile organic compound (VOC) distribution in the Mexico City Metropolitan Area (MCMA) and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs) but with a substantial contribution from oxygenated volatile organic compounds (OVOCs), predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry) model and MOZART (Model for Ozone and Related chemical Tracers) were able to reproduce the general features of the daytime cycle of the VOC OH reactivity distribution showing that NMHCs dominate the distribution except in the afternoon hours and that the VOC OH reactivity peaks in the early morning due to high morning emissions from the city into a shallow boundary layer. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height. In addition, a plume was studied in which air was advected out of the MCMA and intercepted downwind with the DOE G1 on 18 March and the NCAR C130 one day later on 19 March. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind. Ozone and many OVOCs were photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial and temporal extent of the 19 March plume and to help interpret the OH reactivity in the downwind plume. The model results generally showed good agreement with experimental results for the total VOC OH reactivity downwind and gave insight into the distributions of VOC chemical classes downwind. A box model with detailed gas phase chemistry (NCAR Master Mechanism), initialized with concentrations observed at one of the ground sites in the MCMA, was used to examine the expected evolution of specific VOCs over a 1-2 day period. The models clearly supported the experimental evidence for NMHC oxidation leading to the formation of OVOCs downwind, which then become the primary fuel for ozone production far away from the MCMA.

  2. Chemical evolution of volatile organic compounds in the outflow of the Mexico City Metropolitan area

    SciTech Connect

    Apel, Eric; Emmons, L.; Karl, Thomas G.; Flocke, Frank M.; Hills, A. J.; Madronich, Sasha; Lee-Taylor, J.; Fried, Alan; Weibring, P.; Walega, J.; Richter, Dirk; Tie, X.; Mauldin, L.; Campos, Teresa; Weinheimer, Andrew J.; Knapp, David; Sive, B.; Kleinman, Lawrence I.; Springston, S.; Zaveri, Rahul A.; Ortega, John V.; Voss, Paul B.; Blake, D. R.; Baker, Angela K.; Warneke, Carsten; Welsh-Bon, Daniel; de Gouw, Joost A.; Zheng, J.; Zhang, Renyi; Rudolph, Jochen; Junkermann, W.; Riemer, D.

    2010-01-01

    The volatile organic compound (VOC) distribution in the Mexico City Metropolitan Area (MCMA) and its evolution as it is uplifted and transported out of the MCMA basin was studied during the 2006 MILAGRO/MIRAGE-Mex field campaign. The results show that in the morning hours in the city center, the VOC distribution is dominated by non-methane hydrocarbons (NMHCs) but with a substantial contribution from oxygenated volatile organic compounds (OVOCs), predominantly from primary emissions. Alkanes account for a large part of the NMHC distribution in terms of mixing ratios. In terms of reactivity, NMHCs also dominate overall, especially in the morning hours. However, in the afternoon, as the boundary layer lifts and air is mixed and aged within the basin, the distribution changes as secondary products are formed. The WRF-Chem (Weather Research and Forecasting with Chemistry) model and MOZART (Model for Ozone and Related chemical Tracers) were able to reproduce the general features of the daytime cycle of the VOC OH reactivity distribution showing that NMHCs dominate the distribution except in the afternoon hours and that the VOC OH reactivity peaks in the early morning due to high morning emissions from the city into a shallow boundary layer. The WRF-Chem and MOZART models showed higher reactivity than the experimental data during the nighttime cycle, perhaps indicating problems with the modeled nighttime boundary layer height. In addition, a plume was studied in which air was advected out of the MCMA and intercepted downwind with the DOE G1 on March 18 and the NCAR C130 one day later on March 19. A number of identical species measured aboard each aircraft gave insight into the chemical evolution of the plume as it aged and was transported as far as 1000 km downwind. Ozone and many OVOCs were photochemically produced in the plume. The WRF-Chem and MOZART models were used to examine the spatial and temporal extent of the March 19 plume and to help interpret the OH reactivity in the downwind plume. The model results generally showed good agreement with experimental results for the total VOC OH reactivity downwind and gave insight into the distributions of VOC chemical classes downwind. A box model with detailed gas phase chemistry (NCAR Master Mechanism), initialized with concentrations observed at one of the ground sites in the MCMA, was used to examine the expected evolution of specific VOCs over a 1-2 day period. The models clearly supported the experimental evidence for NMHC oxidation leading to the formation of OVOCs downwind, which then become the primary fuel for ozone production far away from the MCMA.

  3. Acute toxicity of Daphnia pulex to six classes of chemical compounds potentially hazardous to Great Lakes aquatic biota

    USGS Publications Warehouse

    Smith, Stephen B.; Savino, Jacqueline F.; Blouin, Marc A.

    1988-01-01

    Of the six classes of chemicals potentially hazardous to Great Lakes aquatic biota, derivatives of polyaromatic hydrocarbons (PAHs) were the most acutely toxic (48-h EC 50) to Daphnia pulex. The other classes, listed in order of decreasing toxicity were alkyl halides, nitrogen-containing compounds, cyclic alkanes, heterocyclic nitrogen compounds, silicon-containing compounds. O f the 41 compounds representing the six chemical classes, 6 were extremely toxic (> 0.01 - 0.1 mg/L), 11 highly toxic (> 01. - 1.0 mg/L), 20 moderately toxic (> 1.0 - 10.0 mg/L), and 4 slightly toxic (>10 - 100 mg/L). The reference compound, p, p'DDT, was super toxic (< 0.01 mg/L). Based on toxicity and relative abundance (hazard ranking) of the 21 compounds that were detected in tissue of Great Lakes fishes, the classes of compounds that present the greatest threat to Great Lakes aquatic biota are PAH derivatives, alkyl halides, and cyclic aklanes.

  4. Method for identifying biochemical and chemical reactions and micromechanical processes using nanomechanical and electronic signal identification

    DOEpatents

    Holzrichter, John F. (Berkeley, CA); Siekhaus, Wigbert J. (Berkeley, CA)

    1997-01-01

    A scanning probe microscope, such as an atomic force microscope (AFM) or a scanning tunneling microscope (STM), is operated in a stationary mode on a site where an activity of interest occurs to measure and identify characteristic time-varying micromotions caused by biological, chemical, mechanical, electrical, optical, or physical processes. The tip and cantilever assembly of an AFM is used as a micromechanical detector of characteristic micromotions transmitted either directly by a site of interest or indirectly through the surrounding medium. Alternatively, the exponential dependence of the tunneling current on the size of the gap in the STM is used to detect micromechanical movement. The stationary mode of operation can be used to observe dynamic biological processes in real time and in a natural environment, such as polymerase processing of DNA for determining the sequence of a DNA molecule.

  5. Method for identifying biochemical and chemical reactions and micromechanical processes using nanomechanical and electronic signal identification

    DOEpatents

    Holzrichter, J.F.; Siekhaus, W.J.

    1997-04-15

    A scanning probe microscope, such as an atomic force microscope (AFM) or a scanning tunneling microscope (STM), is operated in a stationary mode on a site where an activity of interest occurs to measure and identify characteristic time-varying micromotions caused by biological, chemical, mechanical, electrical, optical, or physical processes. The tip and cantilever assembly of an AFM is used as a micromechanical detector of characteristic micromotions transmitted either directly by a site of interest or indirectly through the surrounding medium. Alternatively, the exponential dependence of the tunneling current on the size of the gap in the STM is used to detect micromechanical movement. The stationary mode of operation can be used to observe dynamic biological processes in real time and in a natural environment, such as polymerase processing of DNA for determining the sequence of a DNA molecule. 6 figs.

  6. A Novel System for Rapidly Identifying Toxic Chemicals During Emergencies UROP Student: Arunkumaar Ganesan (Electrical Engineering and Computer Science)

    E-print Network

    Bhavnani, Suresh K.

    A Novel System for Rapidly Identifying Toxic Chemicals During Emergencies UROP Student: Arunkumaar Ganesan (Electrical Engineering and Computer Science) Faculty Mentor: Suresh K. Bhavnani (Center for Computational Medicine and Biology) Co-authors: Clayton Scott (Electrical Engineering and Computer Science

  7. Chemical oxidation of a malodorous compound, indole, using iron entrapped in calcium alginate beads.

    PubMed

    Ben Hammouda, Samia; Adhoum, Nafaâ; Monser, Lotfi

    2016-01-15

    Iron-alginate beads (Fe-ABs) were successfully prepared by the ion-gelation method, and applied as heterogeneous Fenton catalysts for the removal of a malodorous compound 'indole'. Similarly, copper-enriched alginate beads (Cu-ABs) were synthesized and tested as like-Fenton catalyst, however, their application proved not to be effective for this purpose. Fe-ABs catalysts were characterized by FTIR, SEM, EDS and AAS spectroscopy. Results pointed out that the parameters affecting Fenton catalysis must be carefully chosen to avoid excessive iron release. Under optimal conditions, complete indole removal and considerably high reduction of TOC, without significant leaching was achieved. Indole decay followed a pseudo-first-order kinetics. The absolute rate constant for indole hydroxylation was 3.59×10(9)M(-1)s(-1), as determined by the competition kinetics method. Four reaction intermediates (Isatin, Dioxindole, Oxindole and Anthralinic acid) were identified by ULC/MS/MS analysis. Short-chain aliphatic carboxylic acids like formic, acetic, oxalic, maleic, oxamic and pyruvic acids were identified by ion exclusion chromatography and as end-products. Based on the identified by-products, a plausible mineralization pathway was proposed. Moreover, the catalyst was recovered quantitatively by simple filtration and reused for several times without significant loss of activity. PMID:26384996

  8. Rosy boas (Lichanura trivirgata) use chemical cues to identify female mice (Mus musculus) with li ers of

    E-print Network

    Clark, Rulon W.

    187 Rosy boas (Lichanura trivirgata) use chemical cues to identify female mice (Mus musculus. In this study, we examined the ability of rosy boas(Lichanuratrivirgata)todiscriminateamongseveralsourcesofpreychemicals.Becauseofthehighfrequencyofneonatal mammals in the diet of erycine boas, we focused on chemical cues from female mice (Mus musculus

  9. Influences of biomass burning during the Transport and Chemical Evolution Over the Pacific (TRACE-P) experiment identified by the regional chemical transport model

    NASA Astrophysics Data System (ADS)

    Tang, Youhua; Carmichael, Gregory R.; Woo, Jung-Hun; Thongboonchoo, Narisara; Kurata, Gakuji; Uno, Itsushi; Streets, David G.; Blake, Donald R.; Weber, Rodney J.; Talbot, Robert W.; Kondo, Yutaka; Singh, Hanwant B.; Wang, Tao

    2003-11-01

    Using a regional chemical transport model, STEM 2K1, and the emission inventory for the Transport and Chemical Evolution Over the Pacific (TRACE-P) period [Woo et al., , this issue], we successfully simulated important features of the biomass burning (BB) CO outflow. Simulated results agree well with the TRACE-P aircraft measurements and Thailand surface observations. On the basis of sensitivity studies with and without biomass emissions, we identified nine flight segments that are affected by biomass plumes during the TRACE-P period and compared the characteristics of the BB air masses with the other air masses. The BB air masses emitted from Southeast Asia contain relatively high HCN (?HCN/?CO ˜ 0.0015) and potassium (?K+/?CO ˜ 0.0038) but very low NOy (?NOy/?CO ˜ 0.005) mixing ratios, which may be associated with the special burning condition in this region. The biomass burning air masses have high ozone production efficiency. The observed ?O3/?NOz values were ˜17 in biomass events and 1.7 in other events. The BB influence on the trace gas distributions can be divided into two categories: the influence through direct reactions and the influence caused by BB aerosols changing J values. These two influences are discussed for the BB-affected TRACE-P flights and for east Asia. The BB influences on chemical species are not only determined by the BB plume intensity but also by the ambient environment caused by other emissions. In Southeast Asia, where the biogenic emissions are very strong, the OH background concentration is low, and the BB gas-phase compounds mainly contribute to OH production. Arranged in the sensitivity to the J value change caused by BB aerosols, we have OH > HO2 > HCHO > O3 when evaluated on a regional average. Averaged over March, the biomass burning net influence is as high as 50% for OH, 40% for HO2, 60% for HCHO, and 10 ppbv for O3 for the layers below 1 km.

  10. Chemical composition and biological activity of four salvia essential oils and individual compounds against two species of mosquitoes.

    PubMed

    Ali, Abbas; Tabanca, Nurhayat; Demirci, Betul; Blythe, Eugene K; Ali, Zulfiqar; Baser, K Husnu Can; Khan, Ikhlas A

    2015-01-21

    The chemical compositions of essential oils obtained from four species of genus Salvia were analyzed by gas chromatography with a flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The main compounds identified from Salvia species essential oils were as follows: 1,8-cineole (71.7%), ?-pinene (5.1%), camphor (4.4%), and ?-pinene (3.8%) in Salvia apiana; borneol (17.4%), ?-eudesmol (10.4%), bornyl acetate (5%), and guaiol (4.8%) in Salvia elegans; bornyl acetate (11.4%), ?-caryophyllene (6.5%), caryophyllene oxide (13.5%), and spathulenol (7.0%) in Salvia leucantha; ?-thujene (25.8%), viridiflorol (20.4%), ?-thujene (5.7%), and camphor (6.4%) in Salvia officinalis. In biting-deterrent bioassays, essential oils of S. leucantha and S. elegans at 10 ?g/cm(2) showed activity similar to that of DEET (97%, N, N-diethyl-m-toluamide) in two species of mosquitoes, whereas the activities of S. officinalis and S. apiana essential oils were lower than those of the other oils or DEET. Pure compounds ?-eudesmol and guaiol showed biting-deterrent activity similar to DEET at 25 nmol/cm(2), whereas the activity of 13-epi-manool, caryophyllene oxide, borneol, bornyl acetate, and ?-caryophyllene was significantly lower than that of ?-eudesmol, guaiol, or DEET. All essential oils showed larvicidal activity except that of S. apiana, which was inactive at the highest dose of 125 ppm against both mosquito species. On the basis of 95% CIs, all of the essential oils showed higher toxicity in Anopheles quadrimaculatus than in Aedes aegypti. The essential oil of S. leucantha with an LC50 value of 6.2 ppm showed highest toxicity in An. quadrimaculatus. PMID:25531412

  11. Identifying developmental toxicity pathways for a subset of ToxCast chemicals using human embryonic stem cells and metabolomics.

    PubMed

    Kleinstreuer, N C; Smith, A M; West, P R; Conard, K R; Fontaine, B R; Weir-Hauptman, A M; Palmer, J A; Knudsen, T B; Dix, D J; Donley, E L R; Cezar, G G

    2011-11-15

    Metabolomics analysis was performed on the supernatant of human embryonic stem (hES) cell cultures exposed to a blinded subset of 11 chemicals selected from the chemical library of EPA's ToxCast™ chemical screening and prioritization research project. Metabolites from hES cultures were evaluated for known and novel signatures that may be indicative of developmental toxicity. Significant fold changes in endogenous metabolites were detected for 83 putatively annotated mass features in response to the subset of ToxCast chemicals. The annotations were mapped to specific human metabolic pathways. This revealed strong effects on pathways for nicotinate and nicotinamide metabolism, pantothenate and CoA biosynthesis, glutathione metabolism, and arginine and proline metabolism pathways. Predictivity for adverse outcomes in mammalian prenatal developmental toxicity studies used ToxRefDB and other sources of information, including Stemina Biomarker Discovery's predictive DevTox® model trained on 23 pharmaceutical agents of known developmental toxicity and differing potency. The model initially predicted developmental toxicity from the blinded ToxCast compounds in concordance with animal data with 73% accuracy. Retraining the model with data from the unblinded test compounds at one concentration level increased the predictive accuracy for the remaining concentrations to 83%. These preliminary results on a 11-chemical subset of the ToxCast chemical library indicate that metabolomics analysis of the hES secretome provides information valuable for predictive modeling and mechanistic understanding of mammalian developmental toxicity. PMID:21925528

  12. Identifying New Candidate Genes and Chemicals Related to Prostate Cancer Using a Hybrid Network and Shortest Path Approach

    PubMed Central

    Yuan, Fei; Zhou, You; Wang, Meng; Yang, Jing; Wu, Kai; Lu, Changhong; Kong, Xiangyin; Cai, Yu-Dong

    2015-01-01

    Prostate cancer is a type of cancer that occurs in the male prostate, a gland in the male reproductive system. Because prostate cancer cells may spread to other parts of the body and can influence human reproduction, understanding the mechanisms underlying this disease is critical for designing effective treatments. The identification of as many genes and chemicals related to prostate cancer as possible will enhance our understanding of this disease. In this study, we proposed a computational method to identify new candidate genes and chemicals based on currently known genes and chemicals related to prostate cancer by applying a shortest path approach in a hybrid network. The hybrid network was constructed according to information concerning chemical-chemical interactions, chemical-protein interactions, and protein-protein interactions. Many of the obtained genes and chemicals are associated with prostate cancer. PMID:26504486

  13. Electrocatalytic processing of renewable biomass-derived compounds for production of chemicals, fuels and electricity

    NASA Astrophysics Data System (ADS)

    Xin, Le

    The dual problems of sustaining the fast growth of human society and preserving the environment for future generations urge us to shift our focus from exploiting fossil oils to researching and developing more affordable, reliable and clean energy sources. Human beings had a long history that depended on meeting our energy demands with plant biomass, and the modern biorefinery technologies realize the effective conversion of biomass to production of transportation fuels, bulk and fine chemicals so to alleviate our reliance on fossil fuel resources of declining supply. With the aim of replacing as much non-renewable carbon from fossil oils with renewable carbon from biomass as possible, innovative R&D activities must strive to enhance the current biorefinery process and secure our energy future. Much of my Ph.D. research effort is centered on the study of electrocatalytic conversion of biomass-derived compounds to produce value-added chemicals, biofuels and electrical energy on model electrocatalysts in AEM/PEM-based continuous flow electrolysis cell and fuel cell reactors. High electricity generation performance was obtained when glycerol or crude glycerol was employed as fuels in AEMFCs. The study on selective electrocatalytic oxidation of glycerol shows an electrode potential-regulated product distribution where tartronate and mesoxalate can be selectively produced with electrode potential switch. This finding then led to the development of AEMFCs with selective production of valuable tartronate or mesoxalate with high selectivity and yield and cogeneration of electricity. Reaction mechanisms of electrocatalytic oxidation of ethylene glycol and 1,2-propanediol were further elucidated by means of an on-line sample collection technique and DFT modeling. Besides electro-oxidation of biorenewable alcohols to chemicals and electricity, electrocatalytic reduction of keto acids (e.g. levulinic acid) was also studied for upgrading biomass-based feedstock to biofuels while achieving renewable electricity storage. Meanwhile, ORR that is often coupled in AEMFCs on the cathode was investigated on non-PGM electrocatalyst with comparable activity to commercial Pt/C. The electro-biorefinery process could be coupled with traditional biorefinery operation and will play a significant role in our energy and chemical landscape.

  14. Theoretical Study of Indium Compounds of Interest for Organometallic Chemical Vapor Deposition

    NASA Technical Reports Server (NTRS)

    Cardelino, B. H.; Moore, C. E.; Cardelino, C. A.; Frazier, D. O.; Backmann, K. J.

    2000-01-01

    The structural. electronic and therinochemical properties of indium compounds which are of interest in halide transport and organometallic chemical vapor deposition processes have been studied by ab initio and statistical mechanics methods. The compounds reported include: indium halides and hydrides (InF, InCl, InCl3, InH, InH2, InH3); indium clusters (In2, In3); methylindium, dimethylindium, and their hydrogen derivatives [In(CH3), In(CH3)H, In(CH3)H2, In(CH3)2, In(CH3)2H]; dimethyl-indium dimer [In2(CH3)4], trimethyl-indium [In(CH3)3]; dehydrogenated methyl, dimethyl and trimethylindium [In(CH3)2CH2, In(CH3)CH2, In(CH2)], trimethylindium adducts with ammonia, trimethylamine and hydrazine [(CH3)3In:NH3, (CH3)3In:N(CH3)3, (CH3)3In:N(H2)N(H2)]; dimethylamino-indium and methylimino-indium [In(CH3)2(NH2), In(CH3)(NH)]; indium nitride and indium nitride dimer (InN, In2N2), indium phosphide, arsenide and antimonide ([InP, InAs, InSb). The predicted electronic properties are based on density functional theory calculations; the calculated thermodynamic properties are reported following the format of the JANAF (Joint Army, Navy, NASA, Air Force) Tables. Equilibrium compositions at two temperatures (298 and 1000 K) have been analyzed for groups of competing simultaneous reactions.

  15. Exploring new 129Xe chemical shift ranges in HXeY compounds: hydrogen more relativistic than xenon.

    PubMed

    Lantto, Perttu; Standara, Stanislav; Riedel, Sebastian; Vaara, Juha; Straka, Michal

    2012-08-21

    Among rare gases, xenon features an unusually broad nuclear magnetic resonance (NMR) chemical shift range in its compounds and as a non-bonded Xe atom introduced into different environments. In this work we show that (129)Xe NMR chemical shifts in the recently prepared, matrix-isolated xenon compounds appear in new, so far unexplored (129)Xe chemical shift ranges. State-of-the-art theoretical predictions of NMR chemical shifts in compounds of general formula HXeY (Y = H, F, Cl, Br, I, -CN, -NC, -CCH, -CCCCH, -CCCN, -CCXeH, -OXeH, -OH, -SH) as well as in the recently prepared ClXeCN and ClXeNC species are reported. The bonding situation of Xe in the studied compounds is rather different from the previously characterized cases as Xe appears in the electronic state corresponding to a situation with a low formal oxidation state, between I and II in these compounds. Accordingly, the predicted (129)Xe chemical shifts occur in new NMR ranges for this nucleus: ca. 500-1000 ppm (wrt Xe gas) for HXeY species and ca. 1100-1600 ppm for ClXeCN and ClXeNC. These new ranges fall between those corresponding to the weakly-bonded Xe(0) atom in guest-host systems (? < 300 ppm) and in the hitherto characterized Xe molecules (? > 2000 ppm). The importance of relativistic effects is discussed. Relativistic effects only slightly modulate the (129)Xe chemical shift that is obtained already at the nonrelativistic CCSD(T) level. In contrast, spin-orbit-induced shielding effects on the (1)H chemical shifts of the H1 atom directly bonded to the Xe center largely overwhelm the nonrelativistic deshielding effects. This leads to an overall negative (1)H chemical shift in the range between -5 and -25 ppm (wrt CH(4)). Thus, the relativistic effects induced by the heavy Xe atom appear considerably more important for the chemical shift of the neighbouring, light hydrogen atom than that of the Xe nucleus itself. The predicted NMR parameters facilitate an unambiguous experimental identification of these novel compounds. PMID:22782133

  16. High-throughput screening for GPR119 modulators identifies a novel compound with anti-diabetic efficacy in db/db mice.

    PubMed

    Zhang, Meng; Feng, Yang; Wang, Jia; Zhao, Jianwei; Li, Ting; He, Min; Yang, Dehua; Nosjean, Olivier; Boutin, Jean; Renard, Pierre; Wang, Ming-Wei

    2013-01-01

    G protein-coupled receptor 119 (GPR119) is highly expressed in pancreatic ? cells and enteroendocrine cells. It is involved in glucose-stimulated insulin secretion and glucagon-like peptide-1 (GLP-1) release, thereby representing a promising target for the treatment of type 2 diabetes. Although a number of GPR119 agonists were developed, no positive allosteric modulator (PAM) to this receptor has been reported. Here we describe a high-throughput assay for screening GPR119 PAMs and agonists simultaneously. Following screening of a small molecule compound library containing 312,000 synthetic and natural product-derived samples, one potent GPR119 agonist with novel chemical structure, MW1219, was identified. Exposure of MIN6 and GLUTag cells to MW1219 enhanced glucose-stimulated insulin secretion and GLP-1 release; once-daily oral dosing of MW1219 for 6 weeks in diabetic db/db mice reduced hemoglobin A1c (HbA1c) and improved plasma glucose, insulin and GLP-1 levels; it also increased glucose tolerance. The results demonstrate that MW1219 is capable of effectively controlling blood glucose level and may have the potential to be developed as a new class of anti-diabetic agents. PMID:23704946

  17. CFam: a chemical families database based on iterative selection of functional seeds and seed-directed compound clustering

    PubMed Central

    Zhang, Cheng; Tao, Lin; Qin, Chu; Zhang, Peng; Chen, Shangying; Zeng, Xian; Xu, Feng; Chen, Zhe; Yang, Sheng Yong; Chen, Yu Zong

    2015-01-01

    Similarity-based clustering and classification of compounds enable the search of drug leads and the structural and chemogenomic studies for facilitating chemical, biomedical, agricultural, material and other industrial applications. A database that organizes compounds into similarity-based as well as scaffold-based and property-based families is useful for facilitating these tasks. CFam Chemical Family database http://bidd2.cse.nus.edu.sg/cfam was developed to hierarchically cluster drugs, bioactive molecules, human metabolites, natural products, patented agents and other molecules into functional families, superfamilies and classes of structurally similar compounds based on the literature-reported high, intermediate and remote similarity measures. The compounds were represented by molecular fingerprint and molecular similarity was measured by Tanimoto coefficient. The functional seeds of CFam families were from hierarchically clustered drugs, bioactive molecules, human metabolites, natural products, patented agents, respectively, which were used to characterize families and cluster compounds into families, superfamilies and classes. CFam currently contains 11 643 classes, 34 880 superfamilies and 87 136 families of 490 279 compounds (1691 approved drugs, 1228 clinical trial drugs, 12 386 investigative drugs, 262 881 highly active molecules, 15 055 human metabolites, 80 255 ZINC-processed natural products and 116 783 patented agents). Efforts will be made to further expand CFam database and add more functional categories and families based on other types of molecular representations. PMID:25414339

  18. Identification of chlorinated solvents degradation zones in clay till by high resolution chemical, microbial and compound specific isotope analysis.

    PubMed

    Damgaard, Ida; Bjerg, Poul L; Bælum, Jacob; Scheutz, Charlotte; Hunkeler, Daniel; Jacobsen, Carsten S; Tuxen, Nina; Broholm, Mette M

    2013-03-01

    The degradation of chlorinated ethenes and ethanes in clay till was investigated at a contaminated site (Vadsby, Denmark) by high resolution sampling of intact cores combined with groundwater sampling. Over decades of contamination, bioactive zones with degradation of trichloroethene (TCE) and 1,1,1-trichloroethane (1,1,1-TCA) to 1,2-cis-dichloroethene (cis-DCE) and 1,1-dichloroethane, respectively, had developed in most of the clay till matrix. Dehalobacter dominated over Dehalococcoides (Dhc) in the clay till matrix corresponding with stagnation of sequential dechlorination at cis-DCE. Sporadically distributed bioactive zones with partial degradation to ethene were identified in the clay till matrix (thickness from 0.10 to 0.22 m). In one sub-section profile the presence of Dhc with the vcrA gene supported the occurrence of degradation of cis-DCE and VC, and in another enriched ?(13)C for TCE, cis-DCE and VC documented degradation. Highly enriched ?(13)C for 1,1,1-TCA (25‰) and cis-DCE (-4‰) suggested the occurrence of abiotic degradation in a third sub-section profile. Due to fine scale heterogeneity the identification of active degradation zones in the clay till matrix depended on high resolution subsampling of the clay till cores. The study demonstrates that an integrated approach combining chemical analysis, molecular microbial tools and compound specific isotope analysis (CSIA) was required in order to document biotic and abiotic degradations in the clay till system. PMID:23357226

  19. DownloadedBy:[UniversityofFlorida]At:13:251February2008 A Chemical Stain for Identifying Arsenic-

    E-print Network

    Florida, University of

    DownloadedBy:[UniversityofFlorida]At:13:251February2008 A Chemical Stain for Identifying Arsenic detection of arsenic in treated wood products is necessary when evaluating possible exposure risks from of specifically identifying arsenic in preservative-treated wood was developed by causing the over

  20. Identifying developmental toxicity pathways for a subset of ToxCast chemicals using human embryonic stem cells and metabolomics

    SciTech Connect

    Kleinstreuer, N.C.; Smith, A.M.; West, P.R.; Conard, K.R.; Fontaine, B.R.; Weir-Hauptman, A.M.; Palmer, J.A.; Knudsen, T.B.; Dix, D.J.; Donley, E.L.R.; Cezar, G.G.; University of Wisconsin-Madison, Madison, WI 53706

    2011-11-15

    Metabolomics analysis was performed on the supernatant of human embryonic stem (hES) cell cultures exposed to a blinded subset of 11 chemicals selected from the chemical library of EPA's ToxCast Trade-Mark-Sign chemical screening and prioritization research project. Metabolites from hES cultures were evaluated for known and novel signatures that may be indicative of developmental toxicity. Significant fold changes in endogenous metabolites were detected for 83 putatively annotated mass features in response to the subset of ToxCast chemicals. The annotations were mapped to specific human metabolic pathways. This revealed strong effects on pathways for nicotinate and nicotinamide metabolism, pantothenate and CoA biosynthesis, glutathione metabolism, and arginine and proline metabolism pathways. Predictivity for adverse outcomes in mammalian prenatal developmental toxicity studies used ToxRefDB and other sources of information, including Stemina Biomarker Discovery's predictive DevTox Registered-Sign model trained on 23 pharmaceutical agents of known developmental toxicity and differing potency. The model initially predicted developmental toxicity from the blinded ToxCast compounds in concordance with animal data with 73% accuracy. Retraining the model with data from the unblinded test compounds at one concentration level increased the predictive accuracy for the remaining concentrations to 83%. These preliminary results on a 11-chemical subset of the ToxCast chemical library indicate that metabolomics analysis of the hES secretome provides information valuable for predictive modeling and mechanistic understanding of mammalian developmental toxicity. -- Highlights: Black-Right-Pointing-Pointer We tested 11 environmental compounds in a hESC metabolomics platform. Black-Right-Pointing-Pointer Significant changes in secreted small molecule metabolites were observed. Black-Right-Pointing-Pointer Perturbed mass features map to pathways critical for normal development and pregnancy. Black-Right-Pointing-Pointer Arginine, proline, nicotinate, nicotinamide and glutathione pathways were affected.

  1. Xlink-Identifier: An Automated Data Analysis Platform for Confident Identifications of Chemically Cross-linked Peptides using Tandem Mass Spectrometry

    SciTech Connect

    Du, Xiuxia; Chowdhury, Saiful M.; Manes, Nathan P.; Wu, Si; Mayer, M. Uljana; Adkins, Joshua N.; Anderson, Gordon A.; Smith, Richard D.

    2011-03-04

    Chemical cross-linking combined with mass spectrometry provides a powerful method for identifying protein-protein interactions and probing the structure of protein complexes. Cross-linking is the process of covalently joining two proteins using cross-linking reagents. After proteolytic cleavage, the cross-linked peptides can be identified using tandem mass spectrometry. A number of strategies have been reported that take advantage of the high sensitivity and high resolution of modern mass spectrometers. Approaches typically include synthesis of novel cross-linking compounds and/or isotopic labelling of the cross-linkering reagent and/or protein to aid both identification and quantitation. However, these approaches have various limitations. These limitations can be overcome with a label-free approach and application of associated data analysis algorithms described in this work.

  2. IDENTIFYING CHEMICALS FOR CUMULATIVE RISK ASSESSMENT USING COMMON MECHANISMS OF ACTION AND TOXICITY

    EPA Science Inventory

    Traditionally, potential health risk assessments from exposure to contaminated food, drinking water, or environmental media have been conducted on individual pesticides or chemicals in each medium of concern. However, humans are generally exposed to multiple chemicals and stress...

  3. Engineering nanoparticles surface for biosensing: "Chemical noses" to detect and identify proteins, bacteria and cancerous cells

    NASA Astrophysics Data System (ADS)

    Miranda-Sanchez, Oscar Ramon

    Rapid and sensitive detection of biomolecules is an important issue in nanomedicine. Many disorders are manifested by changes in protein levels of serum and other biofluids. Rapid and effective differentiation between normal and cancerous cells is an important challenge for the diagnosis and treatment of tumor. Likewise, rapid and effective identification of pathogens is a key target in both biomedical and environmental monitoring. Most biological recognition processes occur via specific interactions. Gold nanoparticles (AuNP s) feature sizes commensurate with biomacromolecules, coupled with useful physical and optical properties. A key issue in the use of nanomaterials is controlling the interfacial interactions of these complex systems. Modulation of these physicochemical properties can be readily achieved by engineering nanoparticles surface. Inspired by the idea of mimicking nature, a convenient, precise and rapid method for sensing proteins, cancerous cells and bacteria has been developed by overtaking the superb performance of biological olfactory systems in odor detection, identification, tracking, and location. On the fundamental side, an array-based/'chemical nose' sensor composed of cationic functionalized AuNPs as receptors and anionic fluorescent conjugated polymers or green fluorescent proteins or enzyme/substrates as transducers that can properly detect and identify proteins, bacteria, and cancerous cells has been successfully fabricated.

  4. Biogeographical Analysis of Chemical Co-Occurrence Data to Identify Priorities for Mixtures Research

    EPA Science Inventory

    A challenge with multiple chemical risk assessment is the need to consider the joint behavior of chemicals in mixtures. To address this need, pharmacologists and toxicologists have developed methods over the years to evaluate and test chemical interaction. In practice, however, t...

  5. Phenotypic Screening of Primary Human Cell Culture Systems to Identify Potential for Compound Toxicity (CHI Phenotypic Screening)

    EPA Science Inventory

    Addressing safety aspects of drugs and environmental chemicals has historically been undertaken through animal testing. However, the quantity of chemicals needing assessment and the challenge of species extrapolation require development of alternative approaches. Assessing phenot...

  6. Eryngial (trans-2-dodecenal), a bioactive compound from Eryngium foetidum: its identification, chemical isolation, characterization and comparison with ivermectin in vitro.

    PubMed

    Forbes, W M; Gallimore, W A; Mansingh, A; Reese, P B; Robinson, R D

    2014-02-01

    Methanol-water (4:1, v/v) crude extracts (50 mg mL(-1)) of 25 Jamaican medicinal plants were screened in vitro for anthelmintic activity using infective third-stage larvae of Strongyloides stercoralis. The most effective extract was further chemically scrutinized to isolate and identify the source of the bioactivity, and the efficacy of this compound was compared with ivermectin. Eosin exclusion (0.1 mg mL(-1)) served as the indicator of mortality in all bioassays. A crude extract of Eryngium foetidum (Apiaceae) was significantly (Probit Analysis, P<0.05) more potent than the other plant extracts, taking 18.9 h to kill 50% (LT50) of the larvae. Further, the petrol extract of E. foetidum was significantly more effective (Probit Analysis, P<0.05) at killing the larvae (LT50, 4.7 h) than either its methanol-water or dichloromethane extract. The latter two effected less than 1% larval mortality after 120 h. With bioassay-driven column chromatography of the petrol extract, trans-2-dodecenal (eryngial) was identified and chemically isolated as the main anthelmintic compound in E. foetidum. There was a significant difference between the 24 h LD50 values (mm) of trans-2-dodecenal (0.461) and ivermectin (2.251) but there was none between the 48 h LD50 values (mm): trans-2-dodecenal (0.411) and ivermectin (0.499) in vitro. PMID:24139239

  7. Antioxidant and Anti-Inflammatory Activity Determination of One Hundred Kinds of Pure Chemical Compounds Using Offline and Online Screening HPLC Assay

    PubMed Central

    Lee, Kwang Jin; Oh, You Chang; Cho, Won Kyung; Ma, Jin Yeul

    2015-01-01

    This study investigated the antioxidant activity of one hundred kinds of pure chemical compounds found within a number of natural substances and oriental medicinal herbs (OMH). Three different methods were used to evaluate the antioxidant activity of DPPH radical-scavenging activity, ABTS radical-scavenging activity, and online screening HPLC-ABTS assays. The results indicated that 17 compounds exhibited better inhibitory activity against ABTS radical than DPPH radical. The IC50 rate of a more practical substance is determined, and the ABTS assay IC50 values of gallic acid hydrate, (+)-catechin hydrate, caffeic acid, rutin hydrate, hyperoside, quercetin, and kaempferol compounds were 1.03 ± 0.25, 3.12 ± 0.51, 1.59 ± 0.06, 4.68 ± 1.24, 3.54 ± 0.39, 1.89 ± 0.33, and 3.70 ± 0.15??g/mL, respectively. The ABTS assay is more sensitive to identifying the antioxidant activity since it has faster reaction kinetics and a heightened response to antioxidants. In addition, there was a very small margin of error between the results of the offline-ABTS assay and those of the online screening HPLC-ABTS assay. We also evaluated the effects of 17 compounds on the NO secretion in LPS-stimulated RAW 264.7 cells and also investigated the cytotoxicity of 17 compounds using a cell counting kit (CCK) in order to determine the optimal concentration that would provide an effective anti-inflammatory action with minimum toxicity. These results will be compiled into a database, and this method can be a powerful preselection tool for compounds intended to be studied for their potential bioactivity and antioxidant activity related to their radical-scavenging capacity. PMID:26504472

  8. Reactivity of target compounds for chemical coal desulfurization. Quarterly technical report, September 1, 1993--November 30, 1993

    SciTech Connect

    Buchanan, D.H.; Amin, M.; Cunningham, R.; Galyen, J.; Tong, Y.

    1993-12-31

    This project seeks to determine the identity of representative organosulfur compounds removed by coal desulfurization reactions. Demineralized coals from the Illinois Basin Coal Sample Program are solvent extracted and the extracts fractionated to separate and concentrate the organosulfur compounds for analysis by Gas Chromatography/Mass Spectroscopy. After the sulfur compounds are characterized, the parent extracts will be subjected to reactions previously shown to reduce the organic sulfur content of Illinois coals. The treated extracts will be fractionated and analyzed for organosulfur content by the same method to determine which compounds reacted during the chemical treatment. Finally, the original coal will be subjected to chemical desulfurization, extraction, fractionation and analysis in order to correlate changes in organic sulfur content of the coal with reactions of specific sulfur compounds. These compounds can thus be reliably considered as target molecules for the next generation of desulfurization processes. Work during this quarter included studies to increase the amount of soluble material extracted from coal by several solvents and development of standard chromatographic methods for fractionation and analysis of soluble coal fractions. Pyridine solubility of several coals is enhanced by removal of mineral matter prior to extraction. The effect is modest (12% relative increase) for Illinois No. 6 coal and greater for lower rank coal. Ultrasound and swelling agents cause a large increase in pyridine solubility. Although toluene extracts much less material from Illinois coals than pyridine, removal of mineral matter prior to extraction causes a relatively larger increase in extraction yield (60 - 80% relative increase). Expected aromatic sulfur compounds such as dibenzothiophene have been detected by GC/MS analysis of non-polar fractions of Illinois No. 6 extracts and several oxidized thiophenes were detected in extracts of weathered IBC-105 coal.

  9. Deduction of the chemical state and the electronic structure of Nd{sub 2}Fe{sub 14}B compound from X-ray photoelectron spectroscopy core-level and valence-band spectra

    SciTech Connect

    Wang, Jing; Liang, Le; Zhang, Lanting E-mail: lmsun@sjtu.edu.cn; Sun, Limin E-mail: lmsun@sjtu.edu.cn; Hirano, Shinichi

    2014-10-28

    Characterization of chemical state and electronic structure of the technologically important Nd{sub 2}Fe{sub 14}B compound is attractive for understanding the physical nature of its excellent magnetic properties. X-ray photoelectron spectroscopy (XPS) study of such rare-earth compound is important and also challenging due to the easy oxidation of surface and small photoelectron cross-sections of rare-earth 4f electrons and B 2p electrons, etc. Here, we reported an investigation based on XPS spectra of Nd{sub 2}Fe{sub 14}B compound as a function of Ar ion sputtering time. The chemical state of Fe and that of B in Nd{sub 2}Fe{sub 14}B compound can be clearly determined to be 0 and ?3, respectively. The Nd in Nd{sub 2}Fe{sub 14}B compound is found to have the chemical state of close to +3 instead of +3 as compared with the Nd in Nd{sub 2}O{sub 3}. In addition, by comparing the valence-band spectrum of Nd{sub 2}Fe{sub 14}B compound to that of the pure Fe, the contributions from Nd, Fe, and B to the valence-band structure of Nd{sub 2}Fe{sub 14}B compound is made more clear. The B 2p states and B 2s states are identified to be at ?11.2 eV and ?24.6 eV, respectively, which is reported for the first time. The contribution from Nd 4f states can be identified both in XPS core-level spectrum and XPS valence-band spectrum. Although Nd 4f states partially hybridize with Fe 3d states, Nd 4f states are mainly localized in Nd{sub 2}Fe{sub 14}B compound.

  10. Data on pigments and long-chain fatty compounds identified in Dietzia sp. A14101 grown on simple and complex hydrocarbons

    PubMed Central

    Hvidsten, Ina; Mjøs, Svein Are; Bødtker, Gunhild; Barth, Tanja

    2015-01-01

    This data article provides: 1. An overview of tentatively identified long chain compounds in Dietzia sp. A14101 grown on simple and complex hydrocarbons; 2. Preliminary Identification of pigments in bacterial material obtained from incubation with a hydrocarbon (dodecane, n-C12) as the only carbon and energy source; 3. Some pictures to illustrate the cell surface charge test. PMID:26442286

  11. Hot wire chemical vapor deposition chemistry in the gas phase and on the catalyst surface with organosilicon compounds.

    PubMed

    Shi, Yujun

    2015-02-17

    CONSPECTUS: Hot wire chemical vapor deposition (HWCVD), also referred to as catalytic CVD (Cat-CVD), has been used to produce Si-containing thin films, nanomaterials, and functional polymer coatings that have found wide applications in microelectronic and photovoltaic devices, in automobiles, and in biotechnology. The success of HWCVD is largely due to its various advantages, including high deposition rate, low substrate temperatures, lack of plasma-induced damage, and large-area uniformity. Film growth in HWCVD is induced by reactive species generated from primary decomposition on the metal wire or from secondary reactions in the gas phase. In order to achieve a rational and efficient optimization of the process, it is essential to identify the reactive species and to understand the chemical kinetics that govern the production of these precursor species for film growth. In this Account, we report recent progress in unraveling the complex gas-phase reaction chemistry in the HWCVD growth of silicon carbide thin films using organosilicon compounds as single-source precursors. We have demonstrated that laser ionization mass spectrometry is a powerful diagnostic tool for studying the gas-phase reaction chemistry when combined with the methods of isotope labeling and chemical trapping. The four methyl-substituted silane molecules, belonging to open-chain alkylsilanes, dissociatively adsorb on W and Ta filaments to produce methyl radical and H2 molecule. Under the typical deposition pressures, with increasing number of methyl substitution, the dominant chemistry occurring in the gas phase switches from silylene/silene reactions to free-radical short chain reactions. This change in dominant reaction intermediates from silylene/silene to methyl radicals explains the observation from thin film deposition that silicon carbide films become more C-rich with a decreasing number of Si-H bonds in the four precursor molecules. In the case of cyclic monosilacyclobutanes, we have shown that ring-opening reactions play a vital role in characterizing the reaction chemistry. On the other hand, exocyclic Si-H(CH3) bond cleavages are more important in the less-puckered disilacyclobutane molecules. Metal filaments are essential in HWCVD since they serve as catalysts to decompose precursor gases to reactive species, which initiate gas-phase reaction chemistry and thin film growth. We discuss the structural changes in metal filaments when exposed to various precursor gases. Depending on the nature of the radical intermediates formed from the hot-wire decomposition and subsequent gas-phase reactions, metal silicides and carbides can be formed. Overall, study of the gas-phase reaction chemistry in HWCVD provides important knowledge of the chemical species produced prior to their deposition on a substrate surface. This helps in identifying the major contributor to alloy formation on the filament itself and the film growth, and consequently, in determining the properties of the deposited films. An integrated knowledge of the gas-phase reaction chemistry, filament alloy formation, and thin film deposition is required for an efficient deposition of high-quality thin films and nanomaterials. PMID:25586211

  12. Cytotoxic Activity and Chemical Composition of the Root Extract from the Mexican Species Linum scabrellum: Mechanism of Action of the Active Compound 6-Methoxypodophyllotoxin

    PubMed Central

    Alejandre-García, Ivonne; Álvarez, Laura; Cardoso-Taketa, Alexandre; González-Maya, Leticia; Antúnez, Mayra; Salas-Vidal, Enrique; Díaz, J. Fernando; Marquina-Bahena, Silvia; Villarreal, María Luisa

    2015-01-01

    The cytotoxic activity and the chemical composition of the dichloromethane/methanol root extract of Linum scabrellum Planchon (Linaceae) were analyzed. Using NMR spectra and mass spectrometry analyses of the extract we identified eight main constituents: oleic acid (1), octadecenoic acid (2), stigmasterol (3), ?-amyrin (4), pinoresinol (5), 6 methoxypodophyllotoxin (6), coniferin (7), and 6-methoxypodophyllotoxin-7-O-?-D-glucopyranoside (8). By using the sulforhodamine B assay, an important cytotoxic activity against four human cancer cell lines, HF6 colon (IC50 = 0.57??g/mL), MCF7 breast (IC50 = 0.56??g/mL), PC3 prostate (IC50 = 1.60??g/mL), and SiHa cervical (IC50 = 1.54??g/mL), as well as toward the normal fibroblasts line HFS-30 IC50 = 1.02??g/mL was demonstrated. Compound 6 (6-methoxypodophyllotoxin) was responsible for the cytotoxic activity exhibiting an IC50 value range of 0.0632 to 2.7433?µg/mL against the tested cell lines. Cell cycle studies with compound 6 exhibited a cell arrest in G2/M of the prostate PC3 cancer cell line. Microtubule disruption studies demonstrated that compound 6 inhibited the polymerization of tubulin through its binding to the colchicine site (binding constant Kb = 7.6 × 106?M?1). A dose-response apoptotic effect was also observed. This work constitutes the first investigation reporting the chemical composition of L. scabrellum and the first study determining the mechanism of action of compound 6. PMID:26246833

  13. Using in Vitro High Throughput Screening Assays to Identify Potential Endocrine-Disrupting Chemicals

    EPA Science Inventory

    Over the past 20 years, an increased focus on detecting environmental chemicals posing a risk of adverse effects due to endocrine disruption has driven the creation of the U.S. EPA Endocrine Disruptor Screening Program (EDSP). Thousands of chemicals are subject to the EDSP, whic...

  14. Identifying multiple eruption phases from a compound tephra blanket: an example of the AD1256 Al-Madinah eruption, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Kawabata, E.; Cronin, S. J.; Bebbington, M. S.; Moufti, M. R. H.; El-Masry, N.; Wang, T.

    2015-01-01

    Complex eruption episodes commonly produce several phases of tephra fall and/or concurrent falls from multiple vents. Phases of eruption are challenging to reconstruct from the geological record, especially where there is a lack of distinct physical or chemical variations during an eruption episode. A statistical method is proposed for identifying the most likely combination of multiple fall lobes for composite tephra deposits, using a new high-resolution tephra fall map from the basaltic AD1256 Harrat Al-Madinah fissure eruption in Saudi Arabia. This dominantly effusive eruption episode lasted 52 days periodically producing tephra from several vents along the fissure. Most tephra was produced from high Hawaiian fountains and dispersed under differing wind conditions. The widest-dispersed tephra occurred under phases of the highest fountains, at least 500 m high and probably closer to 1000 m. These high fountains produced pyroclasts with a broad range of vesicularity. Similar total versus lobe-specific grain size determinations showed little systematic variation of maximum fountain-height phases. Individual tephra lobe properties (vesicle form, density, particle shape and particle-size distribution) in different sectors around the volcano varied only subtly. From the statistical distribution of spot fall-thickness measurements, a semi-empirical tephra fallout model, modified to account for weathering, wind remobilisation and settling, was fitted using maximum likelihood estimation. A range of likely eruption-event scenarios were evaluated, concluding that the AD1256 eruption most likely comprised three separate fall-producing eruptions from its northern vent under differing wind conditions. The first of these occurred concurrently with high-fountaining events from two other major vents southward along the fissure, producing overlapping fall lobes. Applying this method to other similar compound tephra deposits will help elucidate more realistic eruption scenarios and event reconstructions from the geological record.

  15. Heteroepitaxial growth of 3-5 semiconductor compounds by metal-organic chemical vapor deposition for device applications

    NASA Technical Reports Server (NTRS)

    Collis, Ward J.; Abul-Fadl, Ali

    1988-01-01

    The purpose of this research is to design, install and operate a metal-organic chemical vapor deposition system which is to be used for the epitaxial growth of 3-5 semiconductor binary compounds, and ternary and quaternary alloys. The long-term goal is to utilize this vapor phase deposition in conjunction with existing current controlled liquid phase epitaxy facilities to perform hybrid growth sequences for fabricating integrated optoelectronic devices.

  16. Model for the Vaporization of Mixed Organometallic Compounds in the Metalorganic Chemical Vapor Deposition of High Temperature Superconducting Films

    NASA Technical Reports Server (NTRS)

    Meng, Guangyao; Zhou, Gang; Schneider, Roger L.; Sarma, Bimal K.; Levy, Moises

    1993-01-01

    A model of the vaporization and mass transport of mixed organometallics from a single source for thin film metalorganic chemical vapor deposition is presented. A stoichiometric gas phase can be obtained from a mixture of the organometallics in the desired mole ratios, in spite of differences in the volatilities of the individual compounds. Proper film composition and growth rates are obtained by controlling the velocity of a carriage containing the organometallics through the heating zone of a vaporizer.

  17. CHEMICAL IDENTIFICATION OF COMPOUNDS EMANATED BY BIRDS TO DISCOVER HOST-FINDING ATTRACTANTS OF CULEX MOSQUITOES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Human emanations that affect host-seeking by mosquitoes have been studied; this work has resulted in the identification of over 300 compounds that characterize the volatile “odor profile” of humans. Some of these compounds, tested alone and combined in blends, have been shown to attract Aedes aegyp...

  18. Extraction, chemical characterization and biological activity determination of broccoli health promoting compounds.

    PubMed

    Ares, Ana M; Nozal, María J; Bernal, José

    2013-10-25

    Broccoli (Brassica oleracea L. var. Italica) contains substantial amount of health-promoting compounds such as vitamins, glucosinolates, phenolic compounds, and dietary essential minerals; thus, it benefits health beyond providing just basic nutrition, and consumption of broccoli has been increasing over the years. This review gives an overview on the extraction and separation techniques, as well as the biological activity of some of the above mentioned compounds which have been published in the period January 2008 to January 2013. The work has been distributed according to the different families of health promoting compounds discussing the extraction procedures and the analytical techniques employed for their characterization. Finally, information about the different biological activities of these compounds has been also provided. PMID:23899380

  19. A Quantum Chemical and Statistical Study of Cytotoxic Activity of Compounds Isolated from Curcuma zedoaria

    PubMed Central

    Hamdi, Omer Abdalla Ahmed; Anouar, El Hassane; Shilpi, Jamil A.; Trabolsy, Zuhra Bashir Khalifa Al; Zain, Sharifuddin Bin Md; Zakaria, Nur Shahidatul Shida; Zulkefeli, Mohd; Weber, Jean-Frédéric F.; Malek, Sri Nurestri A.; Rahman, Syarifah Nur Syed Abdul; Awang, Khalijah

    2015-01-01

    A series of 21 compounds isolated from Curcuma zedoaria was subjected to cytotoxicity test against MCF7; Ca Ski; PC3 and HT-29 cancer cell lines; and a normal HUVEC cell line. To rationalize the structure–activity relationships of the isolated compounds; a set of electronic; steric and hydrophobic descriptors were calculated using density functional theory (DFT) method. Statistical analyses were carried out using simple and multiple linear regressions (SLR; MLR); principal component analysis (PCA); and hierarchical cluster analysis (HCA). SLR analyses showed that the cytotoxicity of the isolated compounds against a given cell line depend on certain descriptors; and the corresponding correlation coefficients (R2) vary from 0%–55%. MLR results revealed that the best models can be achieved with a limited number of specific descriptors applicable for compounds having a similar basic skeleton. Based on PCA; HCA and MLR analyses; active compounds were classified into subgroups; which was in agreement with the cell based cytotoxicity assay. PMID:25923077

  20. Micro-Spectroscopic Chemical Imaging of Individual Identified Marine Biogenic and Ambient Organic Ice Nuclei (Invited)

    NASA Astrophysics Data System (ADS)

    Knopf, D. A.; Alpert, P. A.; Wang, B.; OBrien, R. E.; Moffet, R. C.; Aller, J. Y.; Laskin, A.; Gilles, M.

    2013-12-01

    Atmospheric ice formation represents one of the least understood atmospheric processes with important implications for the hydrological cycle and climate. Current freezing descriptions assume that ice active sites on the particle surface initiate ice nucleation, however, the nature of these sites remains elusive. Here, we present a new experimental method that allows us to relate physical and chemical properties of individual particles with observed water uptake and ice nucleation ability using a combination of micro-spectroscopic and optical single particle analytical techniques. We apply this method to field-collected particles and particles generated via bursting of bubbles produced by glass frit aeration and plunging water impingement jets in a mesocosm containing artificial sea water and bacteria and/or phytoplankton. The most efficient ice nuclei (IN) within a particle population are identified and characterized. Single particle characterization is achieved by computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy. A vapor controlled cooling-stage coupled to an optical microscope is used to determine the onsets of water uptake, immersion freezing, and deposition ice nucleation of the individual particles as a function of temperature (T) as low as 200 K and relative humidity (RH) up to water saturation. In addition, we perform CCSEM/EDX to obtain on a single particle level the elemental composition of the entire particle population. Thus, we can determine if the IN are exceptional in nature or belong to a major particle type class with respect to composition and size. We find that ambient and sea spray particles are coated by organic material and can induce ice formation under tropospheric relevant conditions. Micro-spectroscopic single particle analysis of the investigated particle samples invokes a potential paradigm shift: Individual ice nucleating particle composition indicates that IN are similar to the majority of particles in the population and not exceptional. This suggests that composition alone may not be a determinant for IN identification. Furthermore, the results suggest that particle abundance may be a crucial parameter for IN efficiency when predicting cloud glaciation processes. These findings would have important consequences for cloud modeling, laboratory ice nucleation experiments, and field measurements.

  1. The radiolysis of aqueous acetonitrile - Compounds of interest to chemical evolution studies

    SciTech Connect

    Draganic, I.G.; Jovanovic, S.

    1980-07-01

    Oxygen free aqueous solutions of CH3CN (0.1 M, pH 6) were exposed to gamma rays from a Co-60 source, the mixtures of nonvolatile radiolytic products was fractionated and the fractions were analysed. Succinic, maleic, fumaric, malonic and pyruvic acids were identified. Glycol aldehyde, glucose and probably ribose were observed in the hydrolysate of fractionated material. It has been suggested that an oligomer is formed which has a fragment with the polyhydroxy structure and on hydrolysis releases the carbohydrates. Radiolytic products which release amino acids on hydrolysis were found in several fractions. The amino acid contents of the hydrolysates were up to about 2.8% of the fraction mass. The presence of several protein and nonprotein amino acids suggests that their origin should be in a peptidic structure, which is probably a fragment of an oligomer radiolytically produced. A direct analysis of the irradiated solution shows the presence of acetaldehyde, propionaldehyde, glyoxal and of biacetyl. Experimental findings are discussed and a free-radical mechanism is proposed to account for the chemical changes observed.

  2. ASSESSMENT OF A FATHEAD MINNOW REPRODUCTION ASSAY FOR IDENTIFYING ENDOCRINE-DISRUPTING CHEMICALS WITH DIVERSE MODES OF ACTION

    EPA Science Inventory

    The US EPA has developed a short-term reproduction test with the fathead minnow to identify potential endocrine disrupting chemicals (EDCs). The assay is initiated by collecting baseline spawning data from reproductively-active adult fathead minnows for 21 d, followed by a 21 d e...

  3. Cell-based chemical genetic screen identifies damnacanthal as an inhibitor of HIV-1 Vpr induced cell death

    E-print Network

    Huang, Jing

    Cell-based chemical genetic screen identifies damnacanthal as an inhibitor of HIV-1 Vpr induced August 2006 Abstract Viral protein R (Vpr), one of the human immunodeficiency virus type 1 (HIV-1. The mechanisms of Vpr have been intensely studied because it is believed that they underlie HIV-1 pathogenesis

  4. Genotoxic effects of volatile organic compounds in a chemical factory as evaluated by the Tradescantia micronucleus assay and by chemical analysis.

    PubMed

    Kim, Jin Kyu; Shin, Hae Shik; Lee, Jae-Hawn; Lee, Jeong-Joo; Lee, Jin-Hong

    2003-11-10

    The clastogenic effects of volatile organic compounds in the workplace air of a chemical factory were studied by means of the Tradescantia micronucleus (Trad-MCN) assay and chemical analysis. Sampling was performed at a chemical factory producing PVC film in Cheong-ju, South Korea. Inflorescences of Tradescantia BNL 4430 were placed for 2, 6, and 9 h at the height of 1.40 m at two locations in the workplace and one outdoor of the chemical industry. Air samplings were conducted in the same places and the collected tube samples were analyzed by automatic thermal desorption/gas chromatography/mass spectrometry (ATD/GC/MS). The frequencies of micronuclei in specimens exposed for 2 h in sites 1-3 were 6.13 +/- 0.47, 5.40 +/- 1.60, and 2.93 +/- 0.43 MCN per 100 tetrads, respectively. GC/MS analysis proved the presence of various volatile organic compounds such as trichloroethylene, toluene, ethyl benzene, (m, p, o)-xylene, styrene, 1,3,5-trimethyl benzene, and 1,2,4-trimethyl benzene. Mean values of toluene measured by 2 h sampling in sites 1-3 were 1946.6, 1368.3, and 340.1 microg/m3, respectively. The toluene concentrations in sites 1 and 2 were at least four to six times higher than that in site 3. The micronucleus frequencies increased with exposure time. In addition, there was a correlation between the micronucleus frequencies and toluene concentration in the air (R2 = 0.96). The results of this in situ monitoring proved the applicability of the Trad-MCN assay combined with chemical analysis for monitoring genotoxic chemicals in the work environment. PMID:14568294

  5. Adverse Outcome Pathways for Embryonic Vascular Disruption and Alternative Methods to Identify Chemical Vascular Disruptor

    EPA Science Inventory

    Chemically induced vascular toxicity during embryonic development can result in a wide range of adverse prenatal outcomes. We used information from genetic mouse models linked to phenotypic outcomes and a vascular toxicity knowledge base to construct an embryonic vascular disrupt...

  6. Identification of chemical compounds present in different fractions of Annona reticulata L. leaf by using GC-MS.

    PubMed

    Rout, Soumya P; Kar, Durga M

    2014-01-01

    GC-MS analysis of fractions prepared from hydro-alcoholic extract of Annona reticulata Linn (Family Annonaceae) leaf revealed the presence of 9,10-dimethyltricyclo[4.2.1.1(2,5)]decane-9,10-diol; 4-(1,5-dihydroxy-2,6,6-trimethylcyclohex-2-enyl)but-3-en-2-one; 3,7-dimethyl-6-nonen-1-ol acetate; 9-octadecenamide,(Z)-; glycerine; D-glucose,6-O-?-D-galactopyranosyl-; desulphosinigrin and ?-methyl-D-mannopyranoside as few of the major compounds in different fractions. The presence of these compounds in the plant has been identified for the first time. PMID:25050939

  7. Chemical and thermal freeze-out of identified hadrons at the LHC

    E-print Network

    Xiangrong Zhu; Huichao Song

    2015-09-11

    This proceeding briefly summarizes our recent VISHNU hybrid model investigations on the chemical and thermal freeze-out of various hadrons species in 2.76 A TeV Pb+Pb collisions. Detailed analysis on the evolution of particle yields and the last elastic collisions distributions during the hadronic evolution reveals that the two multi-strange hadrons, $\\Xi$ and $\\Omega$, experience early chemical and thermal freeze-out when compared with other hadron species.

  8. Using the chemical equilibrium partitioning space to explore factors influencing the phase distribution of compounds involved in secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Wania, F.; Lei, Y. D.; Wang, C.; Abbatt, J. P. D.; Goss, K.-U.

    2014-10-01

    Many atmospheric and chemical variables influence the partitioning equilibrium between gas phase and condensed phases of compounds implicated in the formation of secondary organic aerosol (SOA). The large number of factors and their interaction makes it often difficult to assess their relative importance and concerted impact. Here we introduce a two-dimensional space, which maps regions of dominant atmospheric phase distribution within a coordinate system defined by equilibrium partitioning coefficients between the gas phase, an aqueous phase and a water insoluble organic matter (WIOM) phase. Placing compounds formed from the oxidation of n-alkanes, terpenes and mono-aromatic hydrocarbons on the maps based on their predicted partitioning properties allows for a simple graphical assessment of their equilibrium phase distribution behaviour. Specifically, it allows for the simultaneous visualization and quantitative comparison of the impact on phase distribution of changes in atmospheric parameters (such as temperature, salinity, WIOM phase polarity, organic aerosol load, and liquid water content), and chemical properties (such as oxidation state, molecular size, functionalization, and dimerisation). The graphical analysis reveals that the addition of hydroxyl, carbonyl and carboxyl groups increases the affinity of aliphatic, alicyclic and aromatic hydrocarbons for the aqueous phase more rapidly than their affinity for WIOM, suggesting that the aqueous phase may often be relevant even for substances that are considerably larger than the C2 and C3 compounds that are typically believed to be associated with aqueous SOA. In particular, the maps identify some compounds that contribute to SOA formation if partitioning to both WIOM and aqueous phase is considered, but would remain in the gas phase if either condensed phase were neglected. For example, many semi-volatile ?-pinene oxidation products will contribute to aqueous SOA under the high liquid water content conditions encountered in clouds, but would remain vapours in wet aerosol. It is conceivable to develop parameterizations of "partitioning basis sets" that group compounds with comparable partitioning properties, which - when combined with data on the abundance of those groups of compounds - could serve in the simulation of SOA formation.

  9. Using the chemical equilibrium partitioning space to explore factors influencing the phase distribution of compounds involved in secondary organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Wania, F.; Lei, Y. D.; Wang, C.; Abbatt, J. P. D.; Goss, K.-U.

    2015-03-01

    Many atmospheric and chemical variables influence the partitioning equilibrium between gas phase and condensed phases of compounds implicated in the formation of secondary organic aerosol (SOA). The large number of factors and their interaction makes it often difficult to assess their relative importance and concerted impact. Here we introduce a two-dimensional space which maps regions of dominant atmospheric phase distribution within a coordinate system defined by equilibrium partition coefficients between the gas phase, an aqueous phase and a water-insoluble organic matter (WIOM) phase. Placing compounds formed from the oxidation of n-alkanes, terpenes and mono-aromatic hydrocarbons on the maps based on their predicted partitioning properties allows for a simple graphical assessment of their equilibrium phase distribution behaviour. Specifically, it allows for the simultaneous visualisation and quantitative comparison of the impact on phase distribution of changes in atmospheric parameters (such as temperature, salinity, WIOM-phase polarity, organic aerosol load, and liquid water content) and chemical properties (such as oxidation state, molecular size, functionalisation, and dimerisation). The graphical analysis reveals that the addition of hydroxyl, carbonyl and carboxyl groups increases the affinity of aliphatic, alicyclic and aromatic hydrocarbons for the aqueous phase more rapidly than their affinity for WIOM, suggesting that the aqueous phase may often be relevant even for substances that are considerably larger than the C2 and C3 compounds that are typically believed to be associated with aqueous SOA. In particular, the maps identify some compounds that contribute to SOA formation if partitioning to both WIOM and aqueous phase is considered but would remain in the gas phase if either condensed phase were neglected. For example, many semi-volatile ?-pinene oxidation products will contribute to aqueous SOA under the conditions of high liquid water content encountered in clouds but would remain vapours in wet aerosol. It is conceivable to develop parameterisations of "partitioning basis sets" that group compounds with comparable partitioning properties, which - when combined with data on the abundance of those groups of compounds - could serve in the simulation of SOA formation.

  10. Identifiers Identifiers

    E-print Network

    Brass, Stefan

    , July 1998. . Tim Berners­Lee: Cool URIs don't change. [http://www.w3.org/Provider/Style/URI] . Uniform://archive.ncsa.uiuc.edu/demoweb/url­primer.html] . T. Berners­Lee, R. Fielding, L. Masinter: Uniform Resource Identifiers (URI): Generic Syntax. RFC Names. RFC 1737, December 1994, 7 pages. . T. Berners­Lee, L. Masinter, M. McCahill: Uniform Resource

  11. Identifiers Identifiers

    E-print Network

    Brass, Stefan

    , July 1998. . Tim Berners­Lee: Cool URIs don't change. [http://www.w3.org/Provider/Style/URI] Stefan://archive.ncsa.uiuc.edu/demoweb/url­primer.html] . T. Berners­Lee, R. Fielding, L. Masinter: Uniform Resource Identifiers (URI): Generic Syntax. RFC Names. RFC 1737, December 1994, 7 pages. . T. Berners­Lee, L. Masinter, M. McCahill: Uniform Resource

  12. The UV-filter benzophenone-1 inhibits 17beta-hydroxysteroid dehydrogenase type 3: Virtual screening as a strategy to identify potential endocrine disrupting chemicals.

    PubMed

    Nashev, Lyubomir G; Schuster, Daniela; Laggner, Christian; Sodha, Seloni; Langer, Thierry; Wolber, Gerhard; Odermatt, Alex

    2010-04-15

    The prevalence of male reproductive disorders and testicular cancer is steadily increasing. Because the exposure to chemicals disrupting natural hormone action has been associated with these diseases, it is important to identify endocrine disrupting chemicals (EDCs) and their targets of action. Here, a 3D-structural database that can be applied for virtual screening approaches to facilitate the identification of EDCs was constructed. The database was screened using pharmacophores of 17beta-hydroxysteroid dehydrogenase type 3 (17beta-HSD3), which catalyzes the last step of testosterone synthesis in testicular Leydig cells and plays an essential role during male sexual development. Among other chemicals, benzophenone (BP) UV-filters were predicted as potential 17beta-HSD3 inhibitors. Biological analyses revealed (2,4-dihydroxyphenyl)-phenylmethanone (also known as benzophenone-1, BP-1) as an inhibitor of human 17beta-HSD3 (IC(50) 1.05microM). BP-1 also efficiently blocked conversion of androstenedione to testosterone by mouse and rat 17beta-HSD3 in whole-organ enzyme assays. Moreover, BP-1 antagonized the testosterone-dependent activation of androgen receptors (IC(50) 5.7microM), suggesting synergistic anti-androgenic effects of BP-1 by preventing testosterone formation and blocking receptor activation. In addition, analyses of several commonly used UV-filters on estrogen- and androgen-metabolizing 17beta-HSD enzymes revealed 3-benzylidene camphor (3-BC) and 4-methylbenzylidene camphor (4-MBC) as low micromolar 17beta-HSD2 inhibitors. In conclusion, screening of virtual chemical structure libraries can facilitate the identification of compounds interfering with hormone action. The potential disruption of 17beta-HSD enzyme function by the UV-filters BP-1, 3-BC and 4-MBC requires further investigation and should be considered for safety assessment of these chemicals. PMID:20005209

  13. Stochastic voyages into uncharted chemical space produce a representative library of all possible drug-like compounds.

    PubMed

    Virshup, Aaron M; Contreras-García, Julia; Wipf, Peter; Yang, Weitao; Beratan, David N

    2013-05-15

    The "small molecule universe" (SMU), the set of all synthetically feasible organic molecules of 500 Da molecular weight or less, is estimated to contain over 10(60) structures, making exhaustive searches for structures of interest impractical. Here, we describe the construction of a "representative universal library" spanning the SMU that samples the full extent of feasible small molecule chemistries. This library was generated using the newly developed Algorithm for Chemical Space Exploration with Stochastic Search (ACSESS). ACSESS makes two important contributions to chemical space exploration: it allows the systematic search of the unexplored regions of the small molecule universe, and it facilitates the mining of chemical libraries that do not yet exist, providing a near-infinite source of diverse novel compounds. PMID:23548177

  14. Stochastic voyages into uncharted chemical space produce a representative library of all possible drug-like compounds

    PubMed Central

    Virshup, Aaron M.; Contreras-García, Julia; Wipf, Peter; Yang, Weitao; Beratan, David N.

    2013-01-01

    The “small molecule universe” (SMU), the set of all synthetically feasible organic molecules of 500 Daltons molecular weight or less, is estimated to contain over 1060 structures, making exhaustive searches for structures of interest impractical. Here, we describe the construction of a “representative universal library” spanning the SMU that samples the full extent of feasible small molecule chemistries. This library was generated using the newly developed Algorithm for Chemical Space Exploration with Stochastic Search (ACSESS). ACSESS makes two important contributions to chemical space exploration: it allows the systematic search of the unexplored regions of the small molecule universe, and it facilitates the mining of chemical libraries that do not yet exist, providing a near-infinite source of diverse novel compounds. PMID:23548177

  15. Chemical compounds and toxicological assessments of drinking water stored in polyethylene terephthalate (PET) bottles: A source of controversy reviewed.

    PubMed

    Bach, Cristina; Dauchy, Xavier; Chagnon, Marie-Christine; Etienne, Serge

    2012-03-01

    A declaration of conformity according to European regulation No. 10/2011 is required to ensure the safety of plastic materials in contact with foodstuffs. This regulation established a positive list of substances that are authorized for use in plastic materials. Some compounds are subject to restrictions and/or specifications according to their toxicological data. Despite this, the analysis of PET reveals some non-intentionally added substances (NIAS) produced by authorized initial reactants and additives. Genotoxic and estrogenic activities in PET-bottled water have been reported. Chemical mixtures in bottled water have been suggested as the source of these toxicological effects. Furthermore, sample preparation techniques, such as solid-phase extraction (SPE), to extract estrogen-like compounds in bottled water are controversial. It has been suggested that inappropriate extraction methods and sample treatment may result in false-negative or positive responses when testing water extracts in bioassays. There is therefore a need to combine chemical analysis with bioassays to carry out hazard assessments. Formaldehyde, acetaldehyde and antimony are clearly related to migration from PET into water. However, several studies have shown other theoretically unexpected substances in bottled water. The origin of these compounds has not been clearly established (PET container, cap-sealing resins, background contamination, water processing steps, NIAS, recycled PET, etc.). Here, we surveyed toxicological studies on PET-bottled water and chemical compounds that may be present therein. Our literature review shows that contradictory results for PET-bottled water have been reported, and differences can be explained by the wide variety of analytical methods, bioassays and exposure conditions employed. PMID:22196043

  16. Gaseous chemical compounds in indoor and outdoor air of 602 houses throughout Japan in winter and summer.

    PubMed

    Uchiyama, Shigehisa; Tomizawa, Takuya; Tokoro, Asumo; Aoki, Manami; Hishiki, Mayu; Yamada, Tomomi; Tanaka, Reiko; Sakamoto, Hironari; Yoshida, Tsutomu; Bekki, Kanae; Inaba, Yohei; Nakagome, Hideki; Kunugita, Naoki

    2015-02-01

    A nationwide survey of indoor air quality in Japan was conducted using four types of diffusive samplers. Gaseous chemical compounds such as carbonyls, volatile organic compounds (VOC), acid gases, basic gases, and ozone were measured in indoor and outdoor air of 602 houses throughout Japan in winter and summer. Four kinds of diffusive samplers were used in this study: DSD-BPE/DNPH packed with 2,4-dinitrophenyl hydrazine and trans-1,2-bis(2-pyridyl)ethylene coated silica for ozone and carbonyls; VOC-SD packed with Carboxen 564 particles for volatile organic compounds; DSD-TEA packed with triethanolamine impregnated silica for acid gases; and DSD-NH3 packed with phosphoric acid impregnated silica for basic gases. These samplers are small and lightweight and do not require a power source, hence, it was possible to obtain a large number of air samples via mail from throughout Japan. Almost all compounds in indoor air were present at higher levels in summer than in winter. In particular, formaldehyde, toluene, and ammonia were strongly dependent on temperature, and their levels increased with temperature. The nitrogen dioxide concentration in indoor air particularly increased only during winter and was well correlated with the formic acid concentration (correlation coefficient=0.959). Ozone concentrations in indoor air were extremely low compared with the outdoor concentrations. Ozone flowing from outdoor air may be decomposed quickly by chemical compounds in indoor air; therefore, it is suggested that the indoor/outdoor ratio of ozone represents the ventilation of the indoor environment. PMID:25601740

  17. Transport of chemical and microbial compounds from known wastewater discharges: Potential for use as indicators of human fecal contamination

    USGS Publications Warehouse

    Glassmeyer, S.T.; Furlong, E.T.; Kolpin, D.W.; Cahill, J.D.; Zaugg, S.D.; Werner, S.L.; Meyer, M.T.; Kryak, D.D.

    2005-01-01

    The quality of drinking and recreational water is currently (2005) determined using indicator bacteria. However, the culture tests used to analyze forthese bacteria require a long time to complete and do not discriminate between human and animal fecal material sources. One complementary approach is to use chemicals found in human wastewater, which would have the advantages of (1) potentially shorter analysis times than the bacterial culture tests and (2) being selected for human-source specificity. At 10 locations, water samples were collected upstream and at two successive points downstream from a wastewaster treatment plant (WWTP); a treated effluent sample was also collected at each WWTP. This sampling plan was used to determine the persistence of a chemically diverse suite of emerging contaminants in streams. Samples were also collected at two reference locations assumed to have minimal human impacts. Of the 110 chemical analytes investigated in this project, 78 were detected at least once. The number of compounds in a given sample ranged from 3 at a reference location to 50 in a WWTP effluent sample. The total analyte load at each location varied from 0.018 ??g/L at the reference location to 97.7 ??g/L in a separate WWTP effluent sample. Although most of the compound concentrations were in the range of 0.01-1.0 ??g/L, in some samples, individual concentrations were in the range of 5-38 ??g/L The concentrations of the majority of the chemicals present in the samples generally followed the expected trend: they were either nonexistent or at trace levels in the upstream samples, had their maximum concentrations in the WWTP effluent samples, and then declined in the two downstream samples. This research suggests that selected chemicals are useful as tracers of human wastewater discharge. ?? 2005 American Chemical Society.

  18. High-confidence mapping of chemical compounds and protein complexes reveals novel aspects of chemical stress response in yeastw

    E-print Network

    capability of yeast to a test substance present in its growth medium. Such investigations work under.1039/b911821g Chemical genetics in yeast has shown great potential for clarifying the pharmacology genetics datasets with protein­protein interactions and a comprehensive collection of yeast protein

  19. Changes on physico-chemical properties, lipid oxidation and volatile compounds during the manufacture of celta dry-cured loin.

    PubMed

    Pateiro, M; Franco, D; Carril, J A; Lorenzo, J M

    2015-08-01

    The present study deals with the changes on the main technological characteristics and volatile compounds profile of a traditional Spanish dry-ripened loin from Celta pig breed. The evolution of physicochemical properties, colour, texture, free fatty acid profile and volatile compounds were assessed throughout the process seasoning, post-seasoning and after 30 and 60 days of dry-ripening. As it was expected, pH, moisture and activity water were significantly (P?compounds were identified during the manufacture of Celta dry-cured loin. At the end of process, volatile compounds from microbial activity were the most abundant followed by volatile compounds from lipid oxidation. PMID:26243901

  20. Identify Beta-Hairpin Motifs with Quadratic Discriminant Algorithm Based on the Chemical Shifts

    PubMed Central

    YongE, Feng; GaoShan, Kou

    2015-01-01

    Successful prediction of the beta-hairpin motif will be helpful for understanding the of the fold recognition. Some algorithms have been proposed for the prediction of beta-hairpin motifs. However, the parameters used by these methods were primarily based on the amino acid sequences. Here, we proposed a novel model for predicting beta-hairpin structure based on the chemical shift. Firstly, we analyzed the statistical distribution of chemical shifts of six nuclei in not beta-hairpin and beta-hairpin motifs. Secondly, we used these chemical shifts as features combined with three algorithms to predict beta-hairpin structure. Finally, we achieved the best prediction, namely sensitivity of 92%, the specificity of 94% with 0.85 of Mathew’s correlation coefficient using quadratic discriminant analysis algorithm, which is clearly superior to the same method for the prediction of beta-hairpin structure from 20 amino acid compositions in the three-fold cross-validation. Our finding showed that the chemical shift is an effective parameter for beta-hairpin prediction, suggesting the quadratic discriminant analysis is a powerful algorithm for the prediction of beta-hairpin. PMID:26422468

  1. Using Structural and PhysicalChemical Parameters to Identify, Classify, and Predict

    E-print Network

    Neshich, Goran

    ­function relationship · Nano-environment · Physical­chemical properties · STING database · Electrostatic potential for protein struc- tures. JPD is a part of the STING [2, 3] platform, which provides one of the most, function, and interaction with other macromolecules. Coupled to the JPD, STING's relational database (STING

  2. IDENTIFICATION OF MUTAGENIC COMPOUNDS FORMED DURING CHLORINATION OF HUMIC ACID

    EPA Science Inventory

    Humic acid chlorination products are being studied in an effort to identify the chemicals responsible for the mutagenicity formed during water chlorination. In the present report, nineteen chlorinated organic compounds have been identified and quantified in ether extracts of chlo...

  3. Bacterial release of arsenic ions and organoarsenic compounds from soil contaminated by chemical warfare agents.

    PubMed

    Köhler, M; Hofmann, K; Völsgen, F; Thurow, K; Koch, A

    2001-02-01

    The objective of this paper was to investigate possible participation of microorganisms in the release of soluble arsenical compounds from organoarsenic warfare agents in contaminated soil. A number of bacterial strains were isolated with high resistance against As3+ and As5+ ions which are able to degrade the water insoluble compounds triphenylarsine (TP) and triphenylarsineoxide (TPO). These strains belong to different genera of bacteria. Release of arsenic ions and soluble organoarsenic compounds from soil by the activity of autochthonic soil bacteria and a mixture of the isolated pure cultures was demonstrated by percolation experiments with undisturbed soil samples (core drills) from the contaminated site. This release increased after addition of nutrients (mineral nitrogen and phosphorus, sodium acetate and ethanol) and is nearly independent of the percolation temperature (5 degrees C and 22 degrees C). These results show that bacteria play an important role in the release of arsenical compounds from organoarsenic warfare agent contaminated soil. This release is limited by shortage of water and, above all, of nutrients for the microorganisms in the sandy forest soil. These results are important both for the management and security and possibly for bioremediation of military waste sites containing similar contaminations. Furthermore, this is the first report on bacterial degradation of organoarsenic warfare compounds. PMID:11100795

  4. Students' Predictions about the Sensory Properties of Chemical Compounds: Additive versus Emergent Frameworks

    ERIC Educational Resources Information Center

    Talanquer, Vicente

    2008-01-01

    We investigated general chemistry students' intuitive ideas about the expected properties of the products of a chemical reaction. In particular, we analyzed college chemistry students' predictions about the color, smell, and taste of the products of chemical reactions represented at the molecular level. The study was designed to explore the extent…

  5. hERGAPDbase: a database documenting hERG channel inhibitory potentials and APD-prolongation activities of chemical compounds

    PubMed Central

    Hishigaki, Haretsugu; Kuhara, Satoru

    2011-01-01

    Drug-induced QT interval prolongation is one of the most common reasons for the withdrawal of drugs from the market. In the past decade, at least nine drugs, i.e. terfenadine, astemizole, grepafloxacin, terodiline, droperidol, lidoflazine, sertindole, levomethadyl and cisapride, have been removed from the market or their use has been severely restricted because of drug-induced QT interval prolongation. Therefore, this irregularity is a major safety concern in the case of drugs submitted for regulatory approval. The most common mechanism of drug-induced QT interval prolongation may be drug-related inhibition of the human ether-á-go-go-related gene (hERG) channel, which subsequently results in prolongation of the cardiac action potential duration (APD). hERGAPDbase is a database of electrophysiological experimental data documenting potential hERG channel inhibitory actions and the APD-prolongation activities of chemical compounds. All data entries are manually collected from scientific papers and curated by a person. With hERGAPDbase, we aim to provide useful information for chemical and pharmacological scientists and enable easy access to electrophysiological experimental data on chemical compounds. Database URL: http://www.grt.kyushu-u.ac.jp/hergapdbase/ PMID:21586548

  6. Transport of chemical and microbial compounds from known wastewater discharges: potential for use as indicators of human fecal contamination.

    PubMed

    Glassmeyer, Susan T; Furlong, Edward T; Kolpin, Dana W; Cahill, Jeffery D; Zaugg, Steven D; Werner, Stephen L; Meyer, Michael T; Kryak, David D

    2005-07-15

    The quality of drinking and recreational water is currently (2005) determined using indicator bacteria. However, the culture tests used to analyze forthese bacteria require a long time to complete and do not discriminate between human and animal fecal material sources. One complementary approach is to use chemicals found in human wastewater, which would have the advantages of (1) potentially shorter analysis times than the bacterial culture tests and (2) being selected for human-source specificity. At 10 locations, water samples were collected upstream and at two successive points downstream from a wastewaster treatment plant (WWTP); a treated effluent sample was also collected at each WWTP. This sampling plan was used to determine the persistence of a chemically diverse suite of emerging contaminants in streams. Samples were also collected at two reference locations assumed to have minimal human impacts. Of the 110 chemical analytes investigated in this project, 78 were detected at least once. The number of compounds in a given sample ranged from 3 at a reference location to 50 in a WWTP effluent sample. The total analyte load at each location varied from 0.018 microg/L at the reference location to 97.7 microg/L in a separate WWTP effluent sample. Although most of the compound concentrations were in the range of 0.01-1.0 microg/L, in some samples, individual concentrations were in the range of 5-38 microg/L. The concentrations of the majority of the chemicals present in the samples generally followed the expected trend: they were either nonexistent or at trace levels in the upstream samples, had their maximum concentrations in the WWTP effluent samples, and then declined in the two downstream samples. This research suggests that selected chemicals are useful as tracers of human wastewater discharge. PMID:16082943

  7. Characterizing the Smell of Marijuana by Odor Impact of Volatile Compounds: An Application of Simultaneous Chemical and Sensory Analysis

    PubMed Central

    2015-01-01

    Recent US legislation permitting recreational use of marijuana in certain states brings the use of marijuana odor as probable cause for search and seizure to the forefront of forensic science, once again. This study showed the use of solid-phase microextraction with multidimensional gas chromatography—mass spectrometry and simultaneous human olfaction to characterize the total aroma of marijuana. The application of odor activity analysis offers an explanation as to why high volatile chemical concentration does not equate to most potent odor impact of a certain compound. This suggests that more attention should be focused on highly odorous compounds typically present in low concentrations, such as nonanal, decanol, o-cymene, benzaldehyde, which have more potent odor impact than previously reported marijuana headspace volatiles. PMID:26657499

  8. Changes in physico-chemical properties and volatile compounds throughout the manufacturing process of dry-cured foal loin.

    PubMed

    Lorenzo, José M; Carballo, J

    2015-01-01

    Physico-chemical, textural, lipolytic and volatile compound changes that occur during the manufacture of dry-cured foal loin were studied. Hardness and chewiness increased significantly (P<0.001) from 1.67 kg and 0.48 kg ? mm to 18.33 kg and 5.01 kg?mm, respectively during ripening process. The total average content of free fatty acid increased significantly (P<0.001), from 768.8 mg/100g of fat in the loins immediately after the seasoning period to 1271.1mg/100g of fat at the end of the drying-ripening period. In the final product, aldehydes became the dominant volatile compounds. PMID:25280362

  9. The Arctic seasonal snow pack as a transfer mechanism and a reactor for lower atmosphere chemical compounds (Invited)

    NASA Astrophysics Data System (ADS)

    Douglas, T. A.

    2013-12-01

    The Polar Regions are snow covered for two thirds of the year (or longer) and in many locations there are few melt events during the winter. As a consequence, the late winter snow pack presents a spatial and temporal archive of the previous winter's precipitation, snow-atmosphere exchange, and within snow pack physical and chemical processes. However, to use the snow pack as a 'sensor' we have to understand the physical and chemical exchange processes between atmospheric compounds and snow and ice surfaces. Of equal importance is knowledge of the reactions that occur in and on snow and ice particle surfaces. Recent research has provided insights on the pathways individual compounds take from the lower atmosphere to snow and on the physical and chemical processes occurring within the snow pack at a variety of scales. Snow on or near sea ice has markedly higher major ion concentrations than snow on the terrestrial snow pack, most notably for chloride and bromide. This difference in chemical composition can be dramatic even in coastal regions where the land is only hundreds of meters away. As a consequence, we have to treat chemical cycling processes in/on snow on sea ice and snow on land differently. Since these halogens, particularly bromine, play critical roles in the spring time photochemical reactions that oxidize ozone and mercury their presence and fate on the sea ice snow pack is of particular interest. A future Arctic is expected to have a thinner, more dynamic sea ice cover that will arrive later and melt earlier. The areal extent of young ice production will likely increase markedly. This would lead to a different snow depositional and chemical regime on sea ice with potential ramifications for chemical exchange with the lower atmosphere. The roles of clear sky precipitation ('diamond dust') and surface hoar deposition in providing a unique lower atmospheric 'reactor' and potential source of water equivalence have been largely overlooked. This despite the fact that the highest mercury concentrations measured in surface snow or ice precipitation have been from diamond dust. Yet diamond dust has extremely low concentrations of major ions. This discrepancy may yield clues into how reactive aerosol particles sorb to falling ice crystals or how reactive aerosols provide a nucleation site around which ice accumulates. This presentation will cover recent field measurements addressing these topics with an eye toward how snow physical and chemical processes may be altered as a result of a projected warmer Arctic. Team Environment Canada and Team Desert Research Institute working on the sea ice north of Barrow, Alaska during the BROMEX 2012 field campaign.

  10. Analysis of gaseous toxic industrial compounds and chemical warfare agent simulants by atmospheric pressure ionization mass spectrometry.

    PubMed

    Cotte-Rodríguez, Ismael; Justes, Dina R; Nanita, Sergio C; Noll, Robert J; Mulligan, Christopher C; Sanders, Nathaniel L; Cooks, R Graham

    2006-04-01

    The suitability of atmospheric pressure chemical ionization mass spectrometry as sensing instrumentation for the real-time monitoring of low levels of toxic compounds is assessed, especially with respect to public safety applications. Gaseous samples of nine toxic industrial compounds, NH3, H2S, Cl2, CS2, SO2, C2H4O, HBr, C6H6 and AsH3, and two chemical warfare agent simulants, dimethyl methylphosphonate (DMMP) and methyl salicylate (MeS), were studied. API-MS proves highly suited to this application, with speedy analysis times (<30 seconds), high sensitivity, high selectivity towards analytes, good precision, dynamic range and accuracy. Tandem MS methods were implemented in selected cases for improved selectivity, sensitivity, and limits of detection. Limits of detection in the parts-per-billion and parts-per-trillion range were achieved for this set of analytes. In all cases detection limits were well below the compounds' permissible exposure limits (PELs), even in the presence of added complex mixtures of alkanes. Linear responses, up to several orders of magnitude, were obtained over the concentration ranges studied (sub-ppb to ppm), with relative standard deviations less than 3%, regardless of the presence of alkane interferents. Receiver operating characteristic (ROC) curves are presented to show the performance trade-off between sensitivity, probability of correct detection, and false positive rate. A dynamic sample preparation system for the production of gas phase analyte concentrations ranging from 100 pptr to 100 ppm and capable of admixing gaseous matrix compounds and control of relative humidity and temperature is also described. PMID:16568176

  11. Correlations between chemical reactivity and mutagenic activity against S. typhimurium TA100 for alpha-dicarbonyl compounds as a proof of the mutagenic mechanism.

    PubMed

    Rodríguez Mellado, J M; Ruiz Montoya, M

    1994-01-16

    The mutagenic activities in the Ames test against S. typhimurium TA100 for a series of alpha-dicarbonyl compounds are examined together with the formation constants of the adducts formed between such compounds and guanine and guanosine. Correlations between the equilibrium constants, the apparent reaction enthalpies, and the mutagenic activity are presented. These correlations imply that the mutagenic activity is related to the chemical reactivity of the dicarbonyl compounds with the puric bases. PMID:7506369

  12. Recent efforts in engineering microbial cells to produce new chemical compounds.

    PubMed

    de Boer, Arjo L; Schmidt-Dannert, Claudia

    2003-04-01

    In the process of evolution, variation and combination of basic building blocks has led to an astonishing wealth of secondary metabolites. Recently, the same evolutionary tools have been used to create novel compounds that have not been found in nature. PMID:12714061

  13. Potassium Tris (Oxalato) Ferrate (III): A Versatile Compound to Illustrate the Principles of Chemical Equilibria

    ERIC Educational Resources Information Center

    Gonzalez, Gabriel; Seco, Miquel

    2004-01-01

    The potassium salt is an easy product to synthesize in an introductory course on inorganic chemistry and the students are required to prepare this product in order to improve their laboratory skills and as an introduction to the synthesis of coordination compounds. The complex potassium tris (oxalato) ferrate (III) is used to illustrate the…

  14. ISOTOPIC (14C) AND CHEMICAL COMPOSITION OF ATMOSPHERIC VOLATILE ORGANIC COMPOUND FRACTIONS - PRECURSORS TO OZONE FORMATION

    EPA Science Inventory

    Atmospheric volatile organic compounds (VOCs) are an important factor in the production of ozone near ground level [3]. Many hydrocarbons originate from auto exhaust. However, a number of VOCs, e.g., isoprene, are known to be natural in origin. To develop reliable models for un...

  15. Chemical characterization of bioactive compounds from the endophytic fungus Diaporthe helianthi isolated from Luehea divaricata.

    PubMed

    Specian, Vânia; Sarragiotto, Maria Helena; Pamphile, João Alencar; Clemente, Edmar

    2012-07-01

    Endophytic microorganisms, defined as fungi or bacteria that colonize the interior of plants without causing any immediate negative effects or damages, have reciprocal relationships with host plants. In some cases their presence is beneficial to the host due to the synthesis of bioactive compounds, among which several alcohols, esters, ketones and others that may react with other compounds and may be lethal to pathogenic microorganisms. Diaporthe helianthi (Phomopsis helianthi in its anamorphic phase) is available worldwide, especially in Europe, Asia and America. Isolated in Europe as an agent of the sunflower stem cancer, it has also been endophytically isolated from tropical and temperate plants. A D. helianthi strain isolated from Luehea divaricata has been employed in current research. An investigation of the secondary metabolite from D. helianthi by CC and NMR of (1)H and (13)C yielded the separation of 10 fractions and the identification of the phenolic compound 2(-4 hydroxyphenyl)-ethanol (Tyrosol). Its antimicrobial reaction was tested and the ensuing antagonistic effects on the human pathogenic bacteria Enterococcus hirae, Escherichia coli, Micrococcus luteus, Salmonella typhi, Staphylococcus aureus, phytopathogenic Xanthomonas asc. phaseoli and phytopathogenic fungi were demonstrated. Results show that bioactive compounds and Tyrosol produced by D. helianthi have a biotechnological potential. PMID:24031942

  16. Chemical characterization of bioactive compounds from the endophytic fungus Diaporthe helianthi isolated from Luehea divaricata

    PubMed Central

    Specian, Vânia; Sarragiotto, Maria Helena; Pamphile, João Alencar; Clemente, Edmar

    2012-01-01

    Endophytic microorganisms, defined as fungi or bacteria that colonize the interior of plants without causing any immediate negative effects or damages, have reciprocal relationships with host plants. In some cases their presence is beneficial to the host due to the synthesis of bioactive compounds, among which several alcohols, esters, ketones and others that may react with other compounds and may be lethal to pathogenic microorganisms. Diaporthe helianthi (Phomopsis helianthi in its anamorphic phase) is available worldwide, especially in Europe, Asia and America. Isolated in Europe as an agent of the sunflower stem cancer, it has also been endophytically isolated from tropical and temperate plants. A D. helianthi strain isolated from Luehea divaricata has been employed in current research. An investigation of the secondary metabolite from D. helianthi by CC and NMR of 1H and 13C yielded the separation of 10 fractions and the identification of the phenolic compound 2(-4 hydroxyphenyl)-ethanol (Tyrosol). Its antimicrobial reaction was tested and the ensuing antagonistic effects on the human pathogenic bacteria Enterococcus hirae, Escherichia coli, Micrococcus luteus, Salmonella typhi, Staphylococcus aureus, phytopathogenic Xanthomonas asc. phaseoli and phytopathogenic fungi were demonstrated. Results show that bioactive compounds and Tyrosol produced by D. helianthi have a biotechnological potential. PMID:24031942

  17. A NOVEL ENERGY-EFFICIENT PLASMA CHEMICAL PROCESS FOR THE DESTRUCTION OF VOLATILE TOXIC COMPOUNDS

    EPA Science Inventory

    Removal of low-concentrations (below several percent) of toxic volatile compounds from contaminated air streams is encountered at DOE waste sites in two instances:(i) off-gases resulting from air-stripping of contaminated soils and (ii) effluent from the incineration of highly-co...

  18. EFFECTS OF CHEMICAL SPECIATION ON THE MINERALIZATION OF ORGANIC COMPOUNDS BY MICROORGANISMS

    EPA Science Inventory

    The mineralization of 1.0 to 100 ng/ml of four complexing compounds--oxalate, citrate, nitrilotriacetate (NTA), and ethylene diaminetetraacetate (EDTA)--was tested in media prepared according to equilibrium calculations by a computer program so that the H, Ca, Mg, Fe, or Al compl...

  19. ANALYSIS OF AMBIENT POLAR VOLATILE ORGANIC COMPOUNDS USING CHEMICAL IONIZATION -- ION TRAP DETECTOR

    EPA Science Inventory

    The current approach to measuring trace levels of volatile organic compounds (VOCs) in ambient air requires cryogenic trapping of the analytes, followed by thermal desorption and low-temperature refocussing onto a column for analysis by capillary gas chromatography/mass spectrome...

  20. Scalar relativistic correction to nucleus-independent chemical shifts of coinage-metal compounds: How does the pseudopotential approximation perform?

    NASA Astrophysics Data System (ADS)

    Corminboeuf, Clémence

    2006-02-01

    The performance of commonly used pseudopotentials for calculations of nucleus-independent chemical shifts (NICS) at the center of coinage-metal rings (M 4Li 2 (D 4h), M = Cu, Ag, Au) is investigated. The scalar relativity, which has a non-negligible effect on NICS, is found to be accurately described by the pseudopotential approximation. Overall, good agreement is obtained with all-electron relativistic methods, however, careful comparisons with these calculations and consideration for large triple- ? basis sets are recommended when aiming to accurately define the relative degree of diatropicity among a series of compounds.

  1. Beyond DP4: an Improved Probability for the Stereochemical Assignment of Isomeric Compounds using Quantum Chemical Calculations of NMR Shifts.

    PubMed

    Grimblat, Nicolás; Zanardi, María M; Sarotti, Ariel M

    2015-12-18

    The DP4 probability is one of the most sophisticated and popular approaches for the stereochemical assignment of organic molecules using GIAO NMR chemical shift calculations when only one set of experimental data is available. In order to improve the performance of the method, we have developed a modified probability (DP4+), whose main differences from the original DP4 are the inclusion of unscaled data and the use of higher levels of theory for the NMR calculation procedure. With these modifications, a significant improvement in the overall performance was achieved, providing accurate and confident results in establishing the stereochemistry of 48 challenging isomeric compounds. PMID:26580165

  2. Estimation of Physical Properties and Chemical Reactivity Parameters of Organic Compounds for Environmental Modeling by SPARC

    EPA Science Inventory

    Mathematical models for predicting the transport and fate of pollutants in the environment require reactivity parameter values that is value of the physical and chemical constants that govern reactivity. Although empirical structure activity relationships have been developed th...

  3. A study of the tropospheric oxidation of volatile organic compounds using chemical ionization mass spectrometry

    E-print Network

    Broekhuizen, Keith Edward, 1974-

    2002-01-01

    The mechanisms and kinetics of reactions important to the troposphere have been investigated using a high pressure, turbulent, discharge-flow technique coupled to a chemical ionization mass spectrometer. The ability to ...

  4. ANALYSIS OF SOCMI (SYNTHETIC ORGANIC CHEMICAL MANUFACTURING INDUSTRY) VOC (VOLATILE ORGANIC COMPOUND) FUGITIVE EMISSIONS DATA

    EPA Science Inventory

    The report gives results of an examination of fugitive emission data from Synthetic Organic Chemical Manufacturing Industry (SOCMI) processing units (Collected under earlier EPA studies) for correlations between process variables and leak frequency. Although line temperature did ...

  5. EXPOSURE-DOSE-EFFECT LINKAGES FOR CHEMICALLY REACTIVE AIR TOXIC COMPOUNDS

    EPA Science Inventory

    This project represents a multidisciplinary collaboration to develop and test methods for more precisely predicting human exposure-dose-response relationships of respiratory tract irritants. These irritants have the unique property of reacting chemically with proteins and lipids ...

  6. Identification of Chemical Compounds That Inhibit the Function of Glutamyl-tRNA Synthetase from Pseudomonas aeruginosa.

    PubMed

    Hu, Yanmei; Guerrero, Edgar; Keniry, Megan; Manrrique, Joel; Bullard, James M

    2015-10-01

    Pseudomonas aeruginosa glutamyl-tRNA synthetase (GluRS) was overexpressed in Escherichia coli. Sequence analysis indicated that P. aeruginosa GluRS is a discriminating GluRS and, similar to other GluRS proteins, requires the presence of tRNA(Glu) to produce a glutamyl-AMP intermediate. Kinetic parameters for interaction with tRNA were determined and the k(cat) and KM were 0.8 s(-1) and 0.68 µM, respectively, resulting in a k(cat)/KM of 1.18 s(-1) µM(-1). A robust aminoacylation-based scintillation proximity assay (SPA) assay was developed and 800 natural products and 890 synthetic compounds were screened for inhibitory activity against P. aeruginosa GluRS. Fourteen compounds with inhibitory activity were identified. IC50s were in the low micromolar range. The minimum inhibitory concentration (MIC) was determined for each of the compounds against a panel of pathogenic bacteria. Two compounds, BT_03F04 and BT_04B09, inhibited GluRS with IC50s of 21.9 and 24.9 µM, respectively, and both exhibited promising MICs against Gram-positive bacteria. Time-kill studies indicated that one compound was bactericidal and one was bacteriostatic against Gram-positive bacteria. BT_03F04 was found to be noncompetitive with both ATP and glutamic acid, and BT_04B09 was competitive with glutamic acid but noncompetitive with ATP. The compounds were not observed to be toxic to mammalian cells in MTT assays. PMID:26116192

  7. Biomarker responses and chemical analyses in fish indicate leakage of polycyclic aromatic hydrocarbons and other compounds from car tire rubber.

    PubMed

    Stephensen, Eiríkur; Adolfsson-Erici, Margaretha; Celander, Malin; Hulander, Mats; Parkkonen, Jari; Hegelund, Tove; Sturve, Joachim; Hasselberg, Linda; Bengtsson, Madeleine; Förlin, Lars

    2003-12-01

    Rubber tire material contains toxic compounds including oils rich in polycyclic aromatic hydrocarbons (PAH), so-called highly aromatic (HA) oils, as well as other reactive additives used as antioxidants, antiozonants, and vulcanization accelerators. The toxicity of rubber tire leachates to aquatic organisms has been demonstrated before. However, previous studies have focused on lethal rather than sublethal effects. We kept rainbow trout (Oncorhynchus mykiss) in tanks with two types of tires: a tire containing HA oils in the tread or a tire free of HA oils in the tread. After 1 d of exposure, an induction of cytochrome P4501A1 (CYP1A1) was evident in both exposed groups, measured as elevated ethoxyresorufin-O-deethylase (EROD) activity and increased CYP1A1 mRNA levels. After two weeks of exposure, EROD activity and CYP1A1 mRNA were still high in fish exposed to leachate from HA oil-containing tire, whereas the effect was somewhat lower in fish exposed to leachate from HA oil-free tread tire. Compounds in the tire leachates also affected antioxidant parameters. Total glutathione concentration in liver as well as hepatic glutathione reductase, glutathione S-transferase, and glucose-6-phosphate dehydrogenase activities were markedly elevated after two weeks of exposure in both groups. The responses were greater in the group exposed to leachate from HA oil-free tread tire. Vitellogenin measurements did not indicate leakage of estrogenic compounds from the tires. Chemical analyses of bile from exposed fish revealed the presence of hydroxylated PAH as well as aromatic nitrogen compounds indicating uptake of these compounds by the fish. PMID:14713032

  8. JV Task 86 - Identifying the Source of Benzene in Indoor Air Using Different Compound Classes from TO-15 Data

    SciTech Connect

    Steven B. Hawthorne

    2007-04-15

    Volatile organic compound (VOC) data that had already been collected using EPA method TO-15 at four different sites under regulatory scrutiny (a school, strip mall, apartment complex, and business/residential neighborhood) were evaluated to determine whether the source of indoor air benzene was outdoor air or vapor intrusion from contaminated soil. Both the use of tracer organics characteristic of different sources and principal component statistical analysis demonstrated that the source of indoor air at virtually all indoor sampling locations was a result of outdoor air, and not contaminated soil in and near the indoor air-sampling locations. These results show that proposed remediation activities to remove benzene-contaminated soil are highly unlikely to reduce indoor air benzene concentrations. A manuscript describing these results is presently being prepared for submission to a peer-reviewed journal.

  9. A High-content screen identifies compounds promoting the neuronal differentiation and the midbrain dopamine neuron specification of human neural progenitor cells

    PubMed Central

    Rhim, Ji heon; Luo, Xiangjian; Xu, Xiaoyun; Gao, Dongbing; Zhou, Tieling; Li, Fuhai; Qin, Lidong; Wang, Ping; Xia, Xiaofeng; Wong, Stephen T. C.

    2015-01-01

    Small molecule compounds promoting the neuronal differentiation of stem/progenitor cells are of pivotal importance to regenerative medicine. We carried out a high-content screen to systematically characterize known bioactive compounds, on their effects on the neuronal differentiation and the midbrain dopamine (mDA) neuron specification of neural progenitor cells (NPCs) derived from the ventral mesencephalon of human fetal brain. Among the promoting compounds three major pharmacological classes were identified including the statins, TGF-?RI inhibitors, and GSK-3 inhibitors. The function of each class was also shown to be distinct, either to promote both the neuronal differentiation and mDA neuron specification, or selectively the latter, or promote the former but suppress the latter. We then carried out initial investigation on the possible mechanisms underlying, and demonstrated their applications on NPCs derived from human pluripotent stem cells (PSCs). Our study revealed the potential of several small molecule compounds for use in the directed differentiation of human NPCs. The screening result also provided insight into the signaling network regulating the differentiation of human NPCs. PMID:26542303

  10. Predicting physical properties of emerging compounds with limited physical and chemical data: QSAR model uncertainty and applicability to military munitions.

    PubMed

    Bennett, Erin R; Clausen, Jay; Linkov, Eugene; Linkov, Igor

    2009-11-01

    Reliable, up-front information on physical and biological properties of emerging materials is essential before making a decision and investment to formulate, synthesize, scale-up, test, and manufacture a new material for use in both military and civilian applications. Multiple quantitative structure-activity relationships (QSARs) software tools are available for predicting a material's physical/chemical properties and environmental effects. Even though information on emerging materials is often limited, QSAR software output is treated without sufficient uncertainty analysis. We hypothesize that uncertainty and variability in material properties and uncertainty in model prediction can be too large to provide meaningful results. To test this hypothesis, we predicted octanol water partitioning coefficients (logP) for multiple, similar compounds with limited physical-chemical properties using six different commercial logP calculators (KOWWIN, MarvinSketch, ACD/Labs, ALogP, CLogP, SPARC). Analysis was done for materials with largely uncertain properties that were similar, based on molecular formula, to military compounds (RDX, BTTN, TNT) and pharmaceuticals (Carbamazepine, Gemfibrizol). We have also compared QSAR modeling results for a well-studied pesticide and pesticide breakdown product (Atrazine, DDE). Our analysis shows variability due to structural variations of the emerging chemicals may be several orders of magnitude. The model uncertainty across six software packages was very high (10 orders of magnitude) for emerging materials while it was low for traditional chemicals (e.g. Atrazine). Thus the use of QSAR models for emerging materials screening requires extensive model validation and coupling QSAR output with available empirical data and other relevant information. PMID:19793608

  11. High-Throughput Screening Using iPSC-Derived Neuronal Progenitors to Identify Compounds Counteracting Epigenetic Gene Silencing in Fragile X Syndrome.

    PubMed

    Kaufmann, Markus; Schuffenhauer, Ansgar; Fruh, Isabelle; Klein, Jessica; Thiemeyer, Anke; Rigo, Pierre; Gomez-Mancilla, Baltazar; Heidinger-Millot, Valerie; Bouwmeester, Tewis; Schopfer, Ulrich; Mueller, Matthias; Fodor, Barna D; Cobos-Correa, Amanda

    2015-10-01

    Fragile X syndrome (FXS) is the most common form of inherited mental retardation, and it is caused in most of cases by epigenetic silencing of the Fmr1 gene. Today, no specific therapy exists for FXS, and current treatments are only directed to improve behavioral symptoms. Neuronal progenitors derived from FXS patient induced pluripotent stem cells (iPSCs) represent a unique model to study the disease and develop assays for large-scale drug discovery screens since they conserve the Fmr1 gene silenced within the disease context. We have established a high-content imaging assay to run a large-scale phenotypic screen aimed to identify compounds that reactivate the silenced Fmr1 gene. A set of 50,000 compounds was tested, including modulators of several epigenetic targets. We describe an integrated drug discovery model comprising iPSC generation, culture scale-up, and quality control and screening with a very sensitive high-content imaging assay assisted by single-cell image analysis and multiparametric data analysis based on machine learning algorithms. The screening identified several compounds that induced a weak expression of fragile X mental retardation protein (FMRP) and thus sets the basis for further large-scale screens to find candidate drugs or targets tackling the underlying mechanism of FXS with potential for therapeutic intervention. PMID:26024946

  12. Chemical compounds from anthropogenic environment and immune evasion mechanisms: potential interactions.

    PubMed

    Kravchenko, Julia; Corsini, Emanuela; Williams, Marc A; Decker, William; Manjili, Masoud H; Otsuki, Takemi; Singh, Neetu; Al-Mulla, Faha; Al-Temaimi, Rabeah; Amedei, Amedeo; Colacci, Anna Maria; Vaccari, Monica; Mondello, Chiara; Scovassi, A Ivana; Raju, Jayadev; Hamid, Roslida A; Memeo, Lorenzo; Forte, Stefano; Roy, Rabindra; Woodrick, Jordan; Salem, Hosni K; Ryan, Elizabeth P; Brown, Dustin G; Bisson, William H; Lowe, Leroy; Lyerly, H Kim

    2015-06-01

    An increasing number of studies suggest an important role of host immunity as a barrier to tumor formation and progression. Complex mechanisms and multiple pathways are involved in evading innate and adaptive immune responses, with a broad spectrum of chemicals displaying the potential to adversely influence immunosurveillance. The evaluation of the cumulative effects of low-dose exposures from the occupational and natural environment, especially if multiple chemicals target the same gene(s) or pathway(s), is a challenge. We reviewed common environmental chemicals and discussed their potential effects on immunosurveillance. Our overarching objective was to review related signaling pathways influencing immune surveillance such as the pathways involving PI3K/Akt, chemokines, TGF-?, FAK, IGF-1, HIF-1?, IL-6, IL-1?, CTLA-4 and PD-1/PDL-1 could individually or collectively impact immunosurveillance. A number of chemicals that are common in the anthropogenic environment such as fungicides (maneb, fluoxastrobin and pyroclostrobin), herbicides (atrazine), insecticides (pyridaben and azamethiphos), the components of personal care products (triclosan and bisphenol A) and diethylhexylphthalate with pathways critical to tumor immunosurveillance. At this time, these chemicals are not recognized as human carcinogens; however, it is known that they these chemicalscan simultaneously persist in the environment and appear to have some potential interfere with the host immune response, therefore potentially contributing to promotion interacting with of immune evasion mechanisms, and promoting subsequent tumor growth and progression. PMID:26002081

  13. Sampling criteria for identifying human biomonitoring chemical differences in the Canadian Arctic.

    PubMed

    Curren, Meredith S; Davis, Karelyn; Van Oostdam, Jay

    2014-01-01

    Human biomonitoring studies in the Canadian Arctic have measured a wide range of metals and persistent organic pollutants in Aboriginal and non-Aboriginal mothers during two time periods in the Northwest Territories and Nunavut. This analysis provides preliminary estimates on sample sizes and sampling frequencies required to measure significant changes in maternal blood concentrations for PCB 153 and total mercury. For example, sample sizes of 35-40 mothers permit the detection of a 40% decrease in these chemical concentrations between two groups (e.g. communities or regions). Improvements in method sensitivity can be achieved by on-going sampling over multiple time periods (e.g. 4 or 5) in these regions, or increasing sample sizes. PMID:24624369

  14. Chemicals identified in human biological media: a data base. Third annual report, October 1981

    SciTech Connect

    Cone, M.V.; Baldauf, M.F.; Martin, F.M.

    1981-12-01

    Part 2 contains the data base in tabular format. There are two sections, the first with records on nondrug substances, and the second with records on drugs. Chemicals in each section are arranged alphabetically by CAS preferred name, CAS registry number, formula, atomic weight, melting point, boiling point, and vapor pressure. Tissues are listed alphabetically with exposure route, analytical method, number of cases, range, and mean - when available in the source document. A variety of information may also be included that is pertinent to the range and mean as well as experimental design, demography, health effects, pathology, morphology, and toxicity. Review articles are included in the data base; however, no data have been extracted from such documents because the original research articles are included.

  15. An evaluation of the VOST method for non-halogenated compounds at a agricultural chemical manufacturing facility

    SciTech Connect

    Jackson, M.D.; Bursey, J.T.; McGaughey, J.F.; Merrill, R.G.

    1997-12-31

    Laboratory testing and one field evaluation study have been performed to assess the performance of the VOST method non-halogenated volatile organic analytes listed in Title III of the Clean Air Act Amendments of 1990. This paper reports on a second field evaluation study performed at a different source category to demonstrate that the methodology is riot source-specific. An incinerator that burned chemical waste was selected as the second test site. The field test was designed according to the guidelines of EPA Method 301, using gaseous dynamic spiking. Volatile organic compounds were spiked into two of four quadruple VOST trains as a gaseous spike. A minimum of ten quadruple sampling runs each was performed for VOST. Each quadruple run used four collocated sampling probes attached to four similar sampling trains, with two spiked trains and two unspiked trains. Statistical analysis of the results was performed according to the guidelines of EPA Method 301. Using the EPA Method 301 criteria for acceptable performance (correction factor between 0.70 and 1.30, with relative standard deviation of 50% or less), the VOST methodology showed acceptable performance in a chemical waste incinerator emissions matrix for the following compounds: benzene, n-hexane, 2,2,4-trimethylpentane, and toluene.

  16. Direct Analysis of Nonvolatile Chemical Compounds on Surfaces Using a Hand-Held Mass Spectrometer with Synchronized Discharge Ionization Function.

    PubMed

    Wang, Xiao; Zhou, Xiaoyu; Ouyang, Zheng

    2016-01-01

    Synchronized discharge ionization (SDI) was previously developed for hand-held mass spectrometers with discontinuous atmospheric pressure interfaces. The function of SDI has been demonstrated for analysis of volatile organic compounds in air at high sensitivity, which is attributed to the fact that ions were produced next to the ion trap mass analyzer inside the vacuum manifold. In this study, a simple sampling device was designed and fitted to a hand-held mass spectrometer to characterize its potential in direct analysis of low-volatility chemicals on surfaces. Nine chemicals of vapor pressures ranging from 10(-4) to 10(-8) Torr (at room temperature), including pesticides, illicit drugs, and explosives, were selected to evaluate and demonstrate the analytical capability of the designed system. Compounds of vapor pressures below 10(-7) Torr, such as tetryl, cocaine, and tetrahydrocannabinol (THC), have been successfully detected. Direct analysis of pesticides from fruit and explosives from a large surface area has also been demonstrated. Tandem mass analysis was performed, which helped to confirm the analyte identity as well as to improve the signal-to-noise ratio (S/N). PMID:26618852

  17. Effect of ultrasound-assisted freezing on the physico-chemical properties and volatile compounds of red radish.

    PubMed

    Xu, Bao-guo; Zhang, Min; Bhandari, Bhesh; Cheng, Xin-feng; Islam, Md Nahidul

    2015-11-01

    Power ultrasound, which can enhance nucleation rate and crystal growth rate, can also affect the physico-chemical properties of immersion frozen products. In this study, the influence of slow freezing (SF), immersion freezing (IF) and ultrasound-assisted freezing (UAF) on physico-chemical properties and volatile compounds of red radish was investigated. Results showed that ultrasound application significantly improved the freezing rate; the freezing time of ultrasound application at 0.26 W/cm(2) was shorten by 14% and 90%, compared to IF and SF, respectively. UAF products showed significant (p<0.05) reduction in drip loss and phytonutrients (anthocyanins, vitamin C and phenolics) loss. Compared to SF products, IF and UAF products showed better textural preservation and higher calcium content. The radish tissues exhibited better cellular structures under ultrasonic power intensities of 0.17 and 0.26 W/cm(2) with less cell separation and disruption. Volatile compound data revealed that radish aromatic profile was also affected in the freezing process. PMID:26186850

  18. Leaf surface lipophilic compounds as one of the factors of silver birch chemical defense against larvae of gypsy moth.

    PubMed

    Martemyanov, Vyacheslav V; Pavlushin, Sergey V; Dubovskiy, Ivan M; Belousova, Irina A; Yushkova, Yuliya V; Morosov, Sergey V; Chernyak, Elena I; Glupov, Victor V

    2015-01-01

    Plant chemical defense against herbivores is a complex process which involves a number of secondary compounds. It is known that the concentration of leaf surface lipophilic compounds (SLCs), particularly those of flavonoid aglycones are increased with the defoliation treatment of silver birch Betula pendula. In this study we investigated how the alteration of SLCs concentration in the food affects the fitness and innate immunity of the gypsy moth Lymantria dispar. We found that a low SLCs concentrations in consumed leaves led to a rapid larval development and increased females' pupae weight (= fecundity) compared to larvae fed with leaves with high SLCs content. Inversely, increasing the compounds concentration in an artificial diet produced the reverse effects: decreases in both larval weight and larval survival. Low SLCs concentrations in tree leaves differently affected larval innate immunity parameters. For both sexes, total hemocytes count in the hemolymph increased, while the activity of plasma phenoloxidase decreased when larvae consume leaves with reduced content of SLCs. Our results clearly demonstrate that the concentration of SLCs in silver birch leaves affects not only gypsy moth fitness but also their innate immune status which might alter the potential resistance of insects against infections and/or parasitoids. PMID:25816371

  19. Leaf Surface Lipophilic Compounds as One of the Factors of Silver Birch Chemical Defense against Larvae of Gypsy Moth

    PubMed Central

    Martemyanov, Vyacheslav V.; Pavlushin, Sergey V.; Dubovskiy, Ivan M.; Belousova, Irina A.; Yushkova, Yuliya V.; Morosov, Sergey V.; Chernyak, Elena I.; Glupov, Victor V.

    2015-01-01

    Plant chemical defense against herbivores is a complex process which involves a number of secondary compounds. It is known that the concentration of leaf surface lipophilic compounds (SLCs), particularly those of flavonoid aglycones are increased with the defoliation treatment of silver birch Betula pendula. In this study we investigated how the alteration of SLCs concentration in the food affects the fitness and innate immunity of the gypsy moth Lymantria dispar. We found that a low SLCs concentrations in consumed leaves led to a rapid larval development and increased females’ pupae weight (= fecundity) compared to larvae fed with leaves with high SLCs content. Inversely, increasing the compounds concentration in an artificial diet produced the reverse effects: decreases in both larval weight and larval survival. Low SLCs concentrations in tree leaves differently affected larval innate immunity parameters. For both sexes, total hemocytes count in the hemolymph increased, while the activity of plasma phenoloxidase decreased when larvae consume leaves with reduced content of SLCs. Our results clearly demonstrate that the concentration of SLCs in silver birch leaves affects not only gypsy moth fitness but also their innate immune status which might alter the potential resistance of insects against infections and/or parasitoids. PMID:25816371

  20. Identifying rhodamine dye plume sources in near-shore oceanic environments by integration of chemical and visual sensors.

    PubMed

    Tian, Yu; Kang, Xiaodong; Li, Yunyi; Li, Wei; Zhang, Aiqun; Yu, Jiangchen; Li, Yiping

    2013-01-01

    This article presents a strategy for identifying the source location of a chemical plume in near-shore oceanic environments where the plume is developed under the influence of turbulence, tides and waves. This strategy includes two modules: source declaration (or identification) and source verification embedded in a subsumption architecture. Algorithms for source identification are derived from the moth-inspired plume tracing strategies based on a chemical sensor. The in-water test missions, conducted in November 2002 at San Clemente Island (California, USA) in June 2003 in Duck (North Carolina, USA) and in October 2010 at Dalian Bay (China), successfully identified the source locations after autonomous underwater vehicles tracked the rhodamine dye plumes with a significant meander over 100 meters. The objective of the verification module is to verify the declared plume source using a visual sensor. Because images taken in near shore oceanic environments are very vague and colors in the images are not well-defined, we adopt a fuzzy color extractor to segment the color components and recognize the chemical plume and its source by measuring color similarity. The source verification module is tested by images taken during the CPT missions. PMID:23507823

  1. Identifying Rhodamine Dye Plume Sources in Near-Shore Oceanic Environments by Integration of Chemical and Visual Sensors

    PubMed Central

    Tian, Yu; Kang, Xiaodong; Li, Yunyi; Li, Wei; Zhang, Aiqun; Yu, Jiangchen; Li, Yiping

    2013-01-01

    This article presents a strategy for identifying the source location of a chemical plume in near-shore oceanic environments where the plume is developed under the influence of turbulence, tides and waves. This strategy includes two modules: source declaration (or identification) and source verification embedded in a subsumption architecture. Algorithms for source identification are derived from the moth-inspired plume tracing strategies based on a chemical sensor. The in-water test missions, conducted in November 2002 at San Clemente Island (California, USA) in June 2003 in Duck (North Carolina, USA) and in October 2010 at Dalian Bay (China), successfully identified the source locations after autonomous underwater vehicles tracked the rhodamine dye plumes with a significant meander over 100 meters. The objective of the verification module is to verify the declared plume source using a visual sensor. Because images taken in near shore oceanic environments are very vague and colors in the images are not well-defined, we adopt a fuzzy color extractor to segment the color components and recognize the chemical plume and its source by measuring color similarity. The source verification module is tested by images taken during the CPT missions. PMID:23507823

  2. New Approach to Evaluate the Antennal Response of an Adult Predator Insect to Different Volatile Chemical Compounds by using Electroantennogram Technique

    NASA Astrophysics Data System (ADS)

    Shonouda, Mourad L.

    The antennal response of adult syrphid flies to selected plant volatile chemical compounds was investigated in the present study. The main chemical classes and their chemical compounds were aldehydes (nonanal and benzaldehyde), monoterpene-alcohols (linalool and alpha-terpineol), ketones (6-methyl-5-heptene-2-one and 2-undecanone), hydrocarbons (tetradecane) and benzoids (methyl salicylate). Electroantennogram (EAG) records showed that the syrphid antennae were strongly responded to linalool, 6-methyl-5-heptene-2-one and methyl salicylate even at low concentrations, in addition to the high dose concentration of nonanal comparably to the other chemical compounds. The antennae of old syrphid adults were more responsive and elicited higher levels of responses to all compounds rather than young syrphid adults. The antennal sensitivity may differ from one compound to another according to the sex. The difference in responses could be attributed to the sensitivity of olfactory receptors and/or the characterization of binding protein(s). The quality of biocontrol agent could be improved if the chemical interaction between beneficial natural enemies and the surrounding environment is intensively studied and we clearly understand the chemical ecology of each natural enemy.

  3. Chemicals with weak skin sensitizing properties can be identified using low-density microarrays on immature dendritic cells.

    PubMed

    Cluzel-Tailhardat, M; Bonnet-Duquennoy, M; de Queral, D Pelle; Vocanson, M; Kurfürst, R; Courtellemont, P; Le Varlet, B; Nicolas, J-F

    2007-11-01

    A critical step in the induction of allergic contact dermatitis is the interaction of haptens with immature dendritic cells (iDC) leading to their activation. Therefore iDC appear as suitable targets for the evaluation of the sensitizing properties of haptens with the aim of developing in vitro toxicologic methods. Here, using a low-density cDNA-array, we analyzed the expression of 165 genes related to dendritic cell biology in human iDC following a 24h incubation with four haptens representative of strong (DNBS), moderate (isoeugenol) and weak (eugenol, hydroxycitronellal) contact sensitizers and with one irritant sodium dodecyl sulphate (SDS). Results show that 21/165 iDC genes were significantly modulated by hapten treatment. Some genes were preferentially modulated by a given chemical. Thus, DNBS, isoeugenol, eugenol and hydroxycitronellal consistently modulated CCR5, CCL27, CCL2 and CCR7, respectively, whereas the CXCL10 gene was regulated by SDS. When subjected to principal component analysis, the 21 target genes fell into four groups associated with a particular type of chemical endowed with distinct sensitizing or irritant properties. Thus, gene profiling of iDC using low-density microarray allows, for screening of chemicals, the indentification of weak haptens with potential skin sensitizing properties. These results suggest that gene profiling of iDC using low-density microarrays may be useful to identify chemicals with weak skin sensitizing properties. PMID:17936526

  4. Attomole detection of isotope-labeled compounds in chemical defense research

    SciTech Connect

    Vogel, J.S.; Buchholz, B.A.; Pawley, N.H.; Mauthe, R.E.; Dingley, K.; Turteltaub, K.

    1996-11-01

    AMS detects 14C at zeptomole to femtomole sensitivities. We detected the effect of ChE-blocking pyridostigmine bromide on the CNS uptake of a pyrethroid insecticide at scaled human-equivalent exposures in rats. Significant blood to brain protection from permethrin dosed at 5mg/kg is seen in the CNS of rats receiving pyridostigmine bromide pretreatments in chow at 2mg/kg/day. The synergy of these compounds was suggested as a precursor to some symptoms of `Gulf War Syndrome`.

  5. Chemical decomposition of iron in Spanish coal pyrolysis identified by Moessbauer spectroscopy at different temperatures

    SciTech Connect

    Ahmed, M.A.; Blesa, M.J.; Moliner, R.

    2007-07-01

    Three chars from lignite (Se), sub bituminous (AA6), bituminous (BCA) Spanish coals produced at 673 K, 773 K, and 873 K were analyzed by Moessbauer spectroscopy at room temperature, and 80 K, except BCA char produced at 873 K, its analysis was extended down to 10 K. Least square fit analysis for the spectra of Se chars showed that, jarosite/Fe{sup 3+} was hydrolyzed into rozenite/Fe2+ at 873 K. Pyrite was reduced to troilite (FeS) at 773 K. Both jarosite and very broad doublet were observed at T = 673 K. The hyperfine parameters of this phase gave close values to microcrystalline iron in either Fe (II) or Fe (III) states. On the other hand, the spectral analysis of AA6 chars ascertained that rozenite was hydrolyzed to goethite (FeOOH) in the range of 773 K-873 K, whereas pyrite was reduced to pyrrohotite (Fe{sub 1-x}S). However, no chemical changes were observed for jarosite in all AA6-chars. Likewise, siderite was changed into magnetite in the BCA chars produced at 673 K and 773 K. Spectrum performed at 10 K for char produced at 873 K proved the presence of ferrihydrite (H = 489.2 kOe), troilite (H = 355.3 kOe) and a broad paramagnetic doublet belonging to an organic iron. These phases and still remaining siderite inferred also that such transformations are incomplete.

  6. Hiding in plain sight: cuticular compound profile matching conceals a larval tortoise beetle in its host chemical cloud.

    PubMed

    Massuda, Kamila Ferreira; Trigo, José Roberto

    2014-04-01

    Larvae of tortoise beetles are postulated to have fecal shields as the main defensive strategy against predators. Such a device protects beetles both physically and chemically. In order to examine how larvae Chelymorpha reimoseri are protected against predatory ants, which frequently visit extrafloral nectaries in their host plant, the morning glory Ipomoea carnea, we conducted anti-predation bioassays with live 5th instars. In the field, larvae in contact with ants had survival between 40 and 73 %, independently of shield presence. In the laboratory, when exposed to Camponotus crassus, larvae with shields had significantly higher survival (85 %) than those without shields (64 %). In both scenarios, larval survival was significantly higher when compared with palatable Spodoptera frugiperda larvae, as the latter were all consumed. We also observed that when C. reimoseri larvae showed no movement, the ants walked on them without attacking. We hypothesized that if the larval integument has a pattern of cuticular compounds (CCs) similar to that of its host plant, larvae would be rendered chemically camouflaged. In the field and laboratory, the freeze-dried palatable larvae of S. frugiperda treated with CCs of 5th instar C. reimoseri and left on I. carnea leaves were significantly less removed by ants than controls without these compounds. We also found a similarity of approximately 50 % between the CCs in C. reimoseri larvae and I. carnea host leaves. Both findings provide evidence in support of the hypothesis that chemical camouflage plays an important role in larval defense, which is reported for the first time in an ectophagous leaf beetle larva. PMID:24744044

  7. Determination of chemical warfare agents and related compounds in environmental samples by solid-phase microextraction with gas chromatography.

    PubMed

    Popiel, Stanis?aw; Sankowska, Monika

    2011-11-25

    Solid phase microextraction (SPME) is an increasingly common method of sample isolation and enhancement. SPME is a convenient and simple sample preparation technique for chromatographic analysis and a useful alternative to liquid-liquid extraction and solid phase extraction. SPME is speed and simply method, which has been widely used in environmental analysis because it is a rather safe method when dealing with highly toxic chemicals. A combination of SPME and gas chromatography (GC) permits both the qualitative and quantitative analysis of toxic industrial compounds, pesticides and chemical warfare agents (CWAs), including their degradation products, in air, water and soil samples. This work presents a combination of SPME and GC methods with various types of detectors in the analysis of CWAs and their degradation products in air, water, soil and other matrices. The combination of SPME and GC methods allows for low detection limits depending on the analyte, matrix and detection system. Commercially available fibers have been mainly used to extract CWAs in headspace analysis. However, attempts have been made to introduce new fiber coatings that are characterized by higher selectivities towards different analytes of interest. Environmental decomposition of CWAs leads to the formation of more hydrophilic products. These compounds may be isolated from samples using SPME and analyzed using GC however, they must often be derivatized first to produce good chromatography. In these cases, one must ensure that the SPME method also meets the same needs. Otherwise, it is helpful to use derivatization methods. SPME may also be used with fieldportable mass spectrometry (MS) and GC-MS instruments for chemical defense applications, including field sampling and analysis. SPME fibers can be taken into contaminated areas to directly sample air, headspaces above solutions, soils and water. PMID:22015307

  8. A comparison of {sup 252}Cf and 14-MeV neutron excitation to identify chemical warfare agents by PGNAA

    SciTech Connect

    Caffrey, A.J.; Harlow, B.D.; Edwards, A.J.; Krebs, K.M.; Jones, J.L.; Yoon, W.; Zabriskie, J.M.; Dougan, A.D.

    2000-07-01

    Since 1992, Idaho National Engineering and Environmental Laboratory's portable isotopic neutron spectrometry (PINS) system has been widely used for the nondestructive assessment of munitions suspected to contain chemical warfare agents, such as the nerve agent sarin. PINS is a {sup 252}Cf-based prompt gamma-ray neutron activation analysis (PGNAA) system. The standard PINS system employs a partially moderated 5-{micro}g {sup 252}Cf source emitting 10{sup 7} n/s to excite the atomic nuclei inside the item under test. The chemical elements inside the item are revealed by their characteristic gamma-ray spectrum, measured by a high-resolution high-purity germanium gamma-ray spectrometer. The system computer then infers the fill compound or mixture from the elemental data extracted from the gamma-ray spectrum. Reliable PINS assessments can be completed in as little as 100 s for favorable cases such as white phosphorus smoke munitions, but normally, a 1000 to 3000 live-second counting interval is required. To improve PINS throughput when hundreds or more munitions must be assessed, they are evaluating the possible advantages of 14-MeV neutron excitation over their current radioisotopic source.

  9. A Novel High-Content Immunofluorescence Assay as a Tool to Identify at the Single Cell Level ?-Globin Inducing Compounds

    PubMed Central

    Durlak, Marta; Fugazza, Cristina; Elangovan, Sudharshan; Marini, Maria Giuseppina; Marongiu, Maria Franca; Moi, Paolo; Fraietta, Ivan; Cappella, Paolo; Barbarani, Gloria; Font-Monclus, Isaura; Mauri, Mario; Ottolenghi, Sergio; Gasparri, Fabio; Ronchi, Antonella

    2015-01-01

    The identification of drugs capable of reactivating ?-globin to ameliorate ?-thalassemia and Sickle Cell anemia is still a challenge, as available ?-globin inducers still have limited clinical indications. High-throughput screenings (HTS) aimed to identify new potentially therapeutic drugs require suitable first-step-screening methods combining the possibility to detect variation in the ?/? globin ratio with the robustness of a cell line. We took advantage of a K562 cell line variant expressing ?-globin (?-K562) to set up a new multiplexed high-content immunofluorescence assay for the quantification of ?- and ?-globin content at single-cell level. The assay was validated by using the known globin inducers hemin, hydroxyurea and butyric acid and further tested in a pilot screening that confirmed HDACs as targets for ?-globin induction (as proved by siRNA-mediated HDAC3 knockdown and by treatment with HDACs inhibitors entinostat and dacinostat) and identified Heme-oxygenases as novel candidate targets for ?-globin induction. Indeed, Heme-oxygenase2 siRNA knockdown as well as its inhibition by Tin protoporphyrin-IX (TinPPIX) greatly increased ?-globin expression. This result is particularly interesting as several metalloporphyrins have already been developed for clinical uses and could be tested (alone or in combination with other drugs) to improve pharmacological ?-globin reactivation for the treatment of ?-hemoglobinopathies. PMID:26509275

  10. Using Ambystoma mexicanum (Mexican axolotl) embryos, chemical genetics, and microarray analysis to identify signaling pathways associated with tissue regeneration.

    PubMed

    Ponomareva, Larissa V; Athippozhy, Antony; Thorson, Jon S; Voss, S Randal

    2015-12-01

    Amphibian vertebrates are important models in regenerative biology because they present exceptional regenerative capabilities throughout life. However, it takes considerable effort to rear amphibians to juvenile and adult stages for regeneration studies, and the relatively large sizes that frogs and salamanders achieve during development make them difficult to use in chemical screens. Here, we introduce a new tail regeneration model using late stage Mexican axolotl embryos. We show that axolotl embryos completely regenerate amputated tails in 7days before they exhaust their yolk supply and begin to feed. Further, we show that axolotl embryos can be efficiently reared in microtiter plates to achieve moderate throughput screening of soluble chemicals to investigate toxicity and identify molecules that alter regenerative outcome. As proof of principle, we identified integration 1 / wingless (Wnt), transforming growth factor beta (Tgf-?), and fibroblast growth factor (Fgf) pathway antagonists that completely block tail regeneration and additional chemicals that significantly affected tail outgrowth. Furthermore, we used microarray analysis to show that inhibition of Wnt signaling broadly affects transcription of genes associated with Wnt, Fgf, Tgf-?, epidermal growth factor (Egf), Notch, nerve growth factor (Ngf), homeotic gene (Hox), rat sarcoma/mitogen-activated protein kinase (Ras/Mapk), myelocytomatosis viral oncogene (Myc), tumor protein 53 (p53), and retinoic acid (RA) pathways. Punctuated changes in the expression of genes known to regulate vertebrate development were observed; this suggests the tail regeneration transcriptional program is hierarchically structured and temporally ordered. Our study establishes the axolotl as a chemical screening model to investigate signaling pathways associated with tissue regeneration. PMID:26092703

  11. Utilizing Chemical Genomics to Identify Cytochrome b as a Novel Drug Target for Chagas Disease

    PubMed Central

    Khare, Shilpi; Roach, Steven L.; Barnes, S. Whitney; Hoepfner, Dominic; Walker, John R.; Chatterjee, Arnab K.; Neitz, R. Jeffrey; Arkin, Michelle R.; McNamara, Case W.; Ballard, Jaime; Lai, Yin; Fu, Yue; Molteni, Valentina; Yeh, Vince; McKerrow, James H.; Glynne, Richard J.; Supek, Frantisek

    2015-01-01

    Unbiased phenotypic screens enable identification of small molecules that inhibit pathogen growth by unanticipated mechanisms. These small molecules can be used as starting points for drug discovery programs that target such mechanisms. A major challenge of the approach is the identification of the cellular targets. Here we report GNF7686, a small molecule inhibitor of Trypanosoma cruzi, the causative agent of Chagas disease, and identification of cytochrome b as its target. Following discovery of GNF7686 in a parasite growth inhibition high throughput screen, we were able to evolve a GNF7686-resistant culture of T. cruzi epimastigotes. Clones from this culture bore a mutation coding for a substitution of leucine by phenylalanine at amino acid position 197 in cytochrome b. Cytochrome b is a component of complex III (cytochrome bc1) in the mitochondrial electron transport chain and catalyzes the transfer of electrons from ubiquinol to cytochrome c by a mechanism that utilizes two distinct catalytic sites, QN and QP. The L197F mutation is located in the QN site and confers resistance to GNF7686 in both parasite cell growth and biochemical cytochrome b assays. Additionally, the mutant cytochrome b confers resistance to antimycin A, another QN site inhibitor, but not to strobilurin or myxothiazol, which target the QP site. GNF7686 represents a promising starting point for Chagas disease drug discovery as it potently inhibits growth of intracellular T. cruzi amastigotes with a half maximal effective concentration (EC50) of 0.15 µM, and is highly specific for T. cruzi cytochrome b. No effect on the mammalian respiratory chain or mammalian cell proliferation was observed with up to 25 µM of GNF7686. Our approach, which combines T. cruzi chemical genetics with biochemical target validation, can be broadly applied to the discovery of additional novel drug targets and drug leads for Chagas disease. PMID:26186534

  12. Identifying vacancy complexes in compound semiconductors with positron annihilation spectroscopy: a case study of InN

    E-print Network

    Rauch, Christian; Tuomisto, Filip

    2011-01-01

    We present a comprehensive study of vacancy and vacancy-impurity complexes in InN combining positron annihilation spectroscopy and ab-initio calculations. Positron densities and annihilation characteristics of common vacancy-type defects are calculated using density functional theory and the feasibility of their experimental detection and distinction with positron annihilation methods is discussed. The computational results are compared to positron lifetime and conventional as well as coincidence Doppler broadening measurements of several representative InN samples. The particular dominant vacancy-type positron traps are identified and their characteristic positron lifetimes, Doppler ratio curves and lineshape parameters determined. We find that In vacancies and their complexes with N vacancies or impurities act as efficient positron traps, inducing distinct changes in the annihilation parameters compared to the InN lattice. Neutral or positively charged N vacancies and pure N vacancy complexes on the other h...

  13. Development of a Cell-Based Fluorescence Polarization Biosensor Using Preproinsulin to Identify Compounds That Alter Insulin Granule Dynamics.

    PubMed

    Yi, Na Young; He, Qingping; Caligan, Thomas B; Smith, Ginger R; Forsberg, Lawrence J; Brenman, Jay E; Sexton, Jonathan Z

    2015-11-01

    Diabetes currently affects 9.3% of the U.S. population totaling $245 billion annually in U.S. direct and indirect healthcare costs. Current therapies for diabetes are limited in their ability to control blood glucose and/or enhance insulin sensitivity. Therefore, innovative and efficacious therapies for diabetes are urgently needed. Herein we describe a fluorescent insulin reporter system (preproinsulin-mCherry, PPI-mCherry) that tracks live-cell insulin dynamics and secretion in pancreatic ?-cells with utility for high-content assessment of real-time insulin dynamics. Additionally, we report a new modality for sensing insulin granule packaging in conventional high-throughput screening (HTS), using a hybrid cell-based fluorescence polarization (FP)/internal FRET biosensor using the PPI-mCherry reporter system. We observed that bafilomycin, a vacuolar H(+) ATPase inhibitor and inhibitor of insulin granule formation, significantly increased mCherry FP in INS-1 cells with PPI-mCherry. Partial least squares regression analysis demonstrated that an increase of FP by bafilomycin is significantly correlated with a decrease in granularity of PPI-mCherry signal in the cells. The increased FP by bafilomycin is due to inhibition of self-Förster resonant energy transfer (homo-FRET) caused by the increased mCherry intermolecular distance. FP substantially decreases when insulin is tightly packaged in the granules, and the homo-FRET decreases when insulin granule packaging is inhibited, resulting in increased FP. We performed pilot HTS of 1782 FDA-approved small molecules and natural products from Prestwick and Enzo chemical libraries resulting in an overall Z'-factor of 0.52?±?0.03, indicating the suitability of this biosensor for HTS. This novel biosensor enables live-cell assessment of protein-protein interaction/protein aggregation in live cells and is compatible with conventional FP plate readers. PMID:26505612

  14. 40 CFR 721.5330 - Nickel salt of an organo compound containing nitrogen.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Nickel salt of an organo compound containing...Specific Chemical Substances § 721.5330 Nickel salt of an organo compound containing...chemical substance generically identified as nickel salt of an organo compound...

  15. 40 CFR 721.5330 - Nickel salt of an organo compound containing nitrogen.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Nickel salt of an organo compound containing...Specific Chemical Substances § 721.5330 Nickel salt of an organo compound containing...chemical substance generically identified as nickel salt of an organo compound...

  16. 40 CFR 721.5330 - Nickel salt of an organo compound containing nitrogen.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Nickel salt of an organo compound containing...Specific Chemical Substances § 721.5330 Nickel salt of an organo compound containing...chemical substance generically identified as nickel salt of an organo compound...

  17. 40 CFR 721.5330 - Nickel salt of an organo compound containing nitrogen.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Nickel salt of an organo compound containing...Specific Chemical Substances § 721.5330 Nickel salt of an organo compound containing...chemical substance generically identified as nickel salt of an organo compound...

  18. 40 CFR 721.5330 - Nickel salt of an organo compound containing nitrogen.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Nickel salt of an organo compound containing...Specific Chemical Substances § 721.5330 Nickel salt of an organo compound containing...chemical substance generically identified as nickel salt of an organo compound...

  19. 40 CFR 721.9668 - Organotin lithium compound.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Organotin lithium compound. 721.9668 Section 721...Substances § 721.9668 Organotin lithium compound. (a) Chemical substance...generically identified as an organotin lithium compound (PMN P-93-1119) is...

  20. 40 CFR 721.9668 - Organotin lithium compound.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Organotin lithium compound. 721.9668 Section 721...Substances § 721.9668 Organotin lithium compound. (a) Chemical substance...generically identified as an organotin lithium compound (PMN P-93-1119) is...

  1. 40 CFR 721.9668 - Organotin lithium compound.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Organotin lithium compound. 721.9668 Section 721...Substances § 721.9668 Organotin lithium compound. (a) Chemical substance...generically identified as an organotin lithium compound (PMN P-93-1119) is...

  2. 40 CFR 721.9668 - Organotin lithium compound.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Organotin lithium compound. 721.9668 Section 721...Substances § 721.9668 Organotin lithium compound. (a) Chemical substance...generically identified as an organotin lithium compound (PMN P-93-1119) is...

  3. 40 CFR 721.9668 - Organotin lithium compound.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Organotin lithium compound. 721.9668 Section 721.9668...Substances § 721.9668 Organotin lithium compound. (a) Chemical substance and significant...generically identified as an organotin lithium compound (PMN P-93-1119) is subject...

  4. An In vivo Chemical Genetic Screen Identifies Phosphodiesterase 4 as a Pharmacological Target for Hedgehog signaling Inhibition

    PubMed Central

    Williams, Charles H.; Hempel, Jonathan E.; Hao, Jijun; Frist, Audrey Y.; Williams, Michelle M.; Fleming, Jonathan T.; Sulikowski, Gary A.; Cooper, Michael K.; Chiang, Chin; Hong, Charles C.

    2015-01-01

    SUMMARY Hedgehog (Hh) signaling plays an integral role in vertebrate development, and its dysregulation has been widely accepted as a driver of numerous malignancies. While a variety of small molecules target Smoothened (Smo) as a strategy for Hh inhibition, Smo gain of function mutations have limited their clinical implementation. Modulation of targets downstream of Smo could define a paradigm for treatment of Hh-dependent cancers. Here, we describe eggmanone, a small molecule identified from a chemical genetic zebrafish screen which induced a Hh-null phenotype. Eggmanone exerts its Hh-inhibitory effects through selective antagonism of phosphodiesterase (PDE) 4, leading to protein kinase A activation and subsequent Hh blockade. Our study implicates PDE4 as a target for Hh inhibition, suggests an improved strategy for Hh-dependent cancer therapy and identifies a unique probe of downstream-of-Smo Hh modulation. PMID:25818300

  5. Gas Chromatography Analysis with Olfactometric Detection (GC-O) as a Useful Methodology for Chemical Characterization of Odorous Compounds

    PubMed Central

    Brattoli, Magda; Cisternino, Ezia; Dambruoso, Paolo Rosario; de Gennaro, Gianluigi; Giungato, Pasquale; Mazzone, Antonio; Palmisani, Jolanda; Tutino, Maria

    2013-01-01

    The gas chromatography-olfactometry (GC-O) technique couples traditional gas chromatographic analysis with sensory detection in order to study complex mixtures of odorous substances and to identify odor active compounds. The GC-O technique is already widely used for the evaluation of food aromas and its application in environmental fields is increasing, thus moving the odor emission assessment from the solely olfactometric evaluations to the characterization of the volatile components responsible for odor nuisance. The aim of this paper is to describe the state of the art of gas chromatography-olfactometry methodology, considering the different approaches regarding the operational conditions and the different methods for evaluating the olfactometric detection of odor compounds. The potentials of GC-O are described highlighting the improvements in this methodology relative to other conventional approaches used for odor detection, such as sensoristic, sensorial and the traditional gas chromatographic methods. The paper also provides an examination of the different fields of application of the GC-O, principally related to fragrances and food aromas, odor nuisance produced by anthropic activities and odorous compounds emitted by materials and medical applications. PMID:24316571

  6. A wireless hybrid chemical sensor for detection of environmental volatile organic compounds.

    PubMed

    Chen, Cheng; Tsow, Francis; Campbell, Katherine Driggs; Iglesias, Rodrigo; Forzani, Erica; Tao, N J

    2013-05-01

    A hybrid sensor for monitoring volatile organic compounds (VOCs) in air is developed. The device combines two orthogonal sensing principles, selective molecular binding with a microfabricated quartz tuning fork detector and separation of analytes with a column. The tuning fork detector is functionalized with molecular imprinted polymers for selective binding to benzene, toluene, ethylbenzene, and xylenes (BTEX), and the separation column provides further discrimination of the analytes for real world complex sample analysis. The device is wireless, portable, battery-powered, and cell-phone operated, and it allows reliable detection in parts per billion (ppb) by volume-levels of BTEX in the presence of complex interferents. The hybrid device is suitable for occupational, environmental health, and epidemiological applications. PMID:24078793

  7. Chemical-meteorological aspects of some atmospheric nitrogen compounds in the tropics (CUBA)

    SciTech Connect

    Cuesta Santos, O.A.; Ortiz Bulto, P.L.; Hurtado, M.S.; Gonzalez, M.L.

    1996-12-31

    The transboundary problems of global and regional atmospheric pollution are at current time, a concern of scientific community and environmentalist, so our region is not considered as an exception on this matter. In our monitoring stations, some studies confirming the presence of nitrogen compounds connected with long range transport have been undertaken. For such reason, the interesting tropospheric chemistry reactions shall be verified. The above mentioned studies include the analysis of NO{sub x} (NO + NO{sub 2}), NH{sub 3}, nitrate and ammonium concentrations in aerosols and rainfall in some monitoring stations its connection with the Kinds of Synoptic Situations (KSS) and the research on back tracks, so all this allows to know its possible sources of origin. As a result of interest it has been found that the total deposition of these compounds oscillates between 0,706 an d3,317 g.m{sup -2} year{sup -1}. The wet deposition exhibits approximately 60%, while the dry one is of 40%. The weight of both depositions depends on our tropical rainy climate`s features. On the other hand, the oxidized nitrogen forms only give 40%, while the reduced ones 60% of total. This coincides more with the power of natural sources in accordance with our climate. The nitrate`s concentrations in aerosols and rainfall connected with Continental Migratory Anticyclone have the higher values than with remaining kinds of synoptic situations influencing on our territory, so it can be concluded that there is transport of these pollutants from continent.

  8. [Investigation of variation of the production of biological and chemical compounds of Hyssopus officinalis L].

    PubMed

    Varga, E; Hajdú, Z; Veres, K; Máthé, I; Németh, E; Pluhár, Z; Bernáth, J

    1998-05-01

    Hyssopus officinalis L. (Lamiaceae family) has been cultivated in Central Europe for a long time. This essential oil containing species serves not only as spice but in many countries including Hungary, it is used as a folk medicine against certain respiratory diseases. Despite this fact, little is known about the variation of its productivity under Central European climatic conditions. The cultivated populations of hyssop can be characterised by a significant heterogenity. In the course of its breeding the uniformity of flower colour (e.g. blue form), and increase in the oil content are the main achievable purposes. The purpose of this work was to investigate both the variability of strains of different crigin and the time-dependent variations of its production parameters. The optimum of phytomass was obtained at the beginning of July. The essential oil content as well as compounds of the non volatile fractions were also investigated. The non volatile fractions for rosmarinic, caffeic acids were analysed mainly by TLC and densitometry. Both compounds were present in all samples and they are suitable for the characterisation of the plant. The essential oils were gained with Water Steam Distillation (WSD) and Supercritical Fluid Extraction (SFE) with CO2. The oils were analysed by GC, GC-MS techniques. In the essential oil composition of the populations studied significant heterogenity could be observed. In the case of applying SFE extraction the oil composition is more uniform, similarly to the obtained by WSD adding hexane. The heterogenity can be experienced in the offsprings, too. If only the main four components (beta-pinene, limonene, pinocamphone, isopinocamphone) are regarded, among the offsprings clear and mixed lines alike can be found. Results of these experiments justify the necessity and usefulness of selection which is going on. PMID:9703705

  9. Chemical Identity Crisis: Glass and Glassblowing in the Identification of Organic Compounds.

    PubMed

    Jackson, Catherine M

    2015-04-01

    This essay explains why and how nineteenth-century chemists sought to stabilize the melting and boiling points of organic substances as reliable characteristics of identity and purity and how, by the end of the century, they established these values as 'Constants of Nature'. Melting and boiling points as characteristic values emerge from this study as products of laboratory standardization, developed by chemists in their struggle to classify, understand and control organic nature. A major argument here concerns the role played by the introduction of organic synthesis in driving these changes. Synthetic organic chemistry vastly increased the number of known organic substances, precipitating the chemical identity crisis of my title. Successful natural product synthesis, moreover, depended on chemists' ability to demonstrate the absolute identity of synthetic product and natural target--something late nineteenth-century chemists eventually achieved by making reliable, replicable melting and boiling point measurements. In the period before the establishment of national standards laboratories, chemists and scientific glassblowers worked together to standardize melting and boiling points as physical constants, such collaborations highlighting the essential importance of chemical glassware and glassblowing skill in the development of nineteenth-century organic chemistry. PMID:26104164

  10. Remote Continuous Wave and Pulsed Laser Raman Detection of Chemical Warfare Agents Simulants and Toxic Industrial Compounds

    NASA Astrophysics Data System (ADS)

    Ortiz-Rivera, William; Pacheco-Londoño, Leonardo C.; Hernández-Rivera, Samuel P.

    2010-09-01

    This study describes the design, assembly, testing and comparison of two Remote Raman Spectroscopy (RRS) systems intended for standoff detection of hazardous chemical liquids. Raman spectra of Chemical Warfare Agents Simulants (CWAS) and Toxic Industrial Compounds (TIC) were measured in the laboratory at a 6.6 m source-target distance using continuous wave (CW) laser detection. Standoff distances for pulsed measurements were 35 m for dimethyl methylphosphonate (DMMP) detection and 60, 90 and 140 m for cyclohexane detection. The prototype systems consisted of a Raman spectrometer equipped with a CCD detector (for CW measurements) and an I-CCD camera with time-gated electronics (for pulsed laser measurements), a reflecting telescope, a fiber optic assembly, a single-line CW laser source (514.5, 488.0, 351.1 and 363.8 nm) and a frequency-doubled single frequency Nd:YAG 532 nm laser (5 ns pulses at 10 Hz). The telescope was coupled to the spectrograph using an optical fiber, and filters were used to reject laser radiation and Rayleigh scattering. Two quartz convex lenses were used to collimate the light from the telescope from which the telescope-focusing eyepiece was removed, and direct it to the fiber optic assembly. To test the standoff sensing system, the Raman Telescope was used in the detection of liquid TIC: benzene, chlorobenzene, toluene, carbon tetrachloride, cyclohexane and carbon disulfide. Other compounds studied were CWAS: dimethylmethyl phosphonate, 2-chloroethyl ethyl sulfide and 2-(butylamino)-ethanethiol. Relative Raman scattering cross sections of liquid CWAS were measured using single-line sources at 532.0, 488.0, 363.8 and 351.1 nm. Samples were placed in glass and quartz vials at the standoff distances from the telescope for the Remote Raman measurements. The mass of DMMP present in water solutions was also quantified as part of the system performance tests.

  11. The environmental behavior and chemical fate of energetic compounds (TNT, RDX, tetryl) in soil and plant systems

    SciTech Connect

    Cataldo, D.A.; Harvey, S.D.; Fellows, R.J.

    1993-06-01

    Munitions materials can accumulate or cycle in terrestrial environs at production and manufacturing facilities and thus pose potential heath and environmental concerns. To address questions related to food chain accumulation, the environmental behavior of energetic compounds (2,4,6-trinitrotoluene,TNT; hexahydro-1,3,5-trinitro-1,3,5-triazine, RDX; 2,4,6-trinitrophenylmethylnitramine, tetryl) was evaluated. Emphasis was placed on determining the potential for soil/plant transfer of munitions residues, translocation and distribution within the plant, the extent to which compounds were metabolized following accumulation, and the chemical nature and form of accumulated residues. Both TNT and tetryl undergo extensive chemical transformation in soil, forming aminodinitrotoluene isomers and N-methyl-2,4,6-trinitroaniline residues, respectively, along with a series of unknowns. After 60 days, only 30% of the amended TNT and 8% of the amended tetryl remained unchanged in the soil. In contrast, 78% of the soil-amended RDX remained unchanged after 60 days. After 60 days, plants grown in soils containing 10 ppm residues contained from 5 {mu}g TNT/g to 600 {mu}g RDX/G fresh wt. tissue. TNT and tetryl residues were primarily accumulated in roots (75%), while RDX was concentrated in leaves and seed. The principal transport form for TNT (root to shoot) was an acid labile conjugate of aminodinitrotoluene; RDX was transported unchanged. On accumulation in roots and leaves, highly polar and non-extractable TNT metabolites dominated, with the aminodinitrotoluene isomers accounting for less than 20% of the residues present. Only a few percent were present as the parent TNT. RDX was partitioned similarly to TNT, with 8 to 30% of the RDX appearing as polar metabolites, 20--50% as parent RDX, and the balance as non-extractable residues. Tetryl was metabolized to N-methyl-2,4,6-trinitroaniline and a variety of polar metabolites.

  12. Emission characteristics of nitrogen- and sulfur-containing odorous compounds during different sewage sludge chemical conditioning processes.

    PubMed

    Liu, Huan; Luo, Guang-Qian; Hu, Hong-Yun; Zhang, Qiang; Yang, Jia-Kuan; Yao, Hong

    2012-10-15

    Chemical conditioners are often used to enhance sewage sludge dewaterability through altering sludge properties and flocs structure, both affect odorous compounds emissions not only during sludge conditioning but also in subsequent sludge disposal. This study was to investigate emission characteristics of ammonia (NH(3)), sulfur dioxide (SO(2)), hydrogen sulfide (H(2)S) and carbonyl sulfide (COS) generated from sewage sludge conditioned by three representative conditioners, i.e., organic polymers, iron salts and skeleton builders, F-S (Fenton's reagent and skeleton builders) composite conditioner. The results demonstrate that polyacrylamide (PAM) has an insignificant effect on emission characteristics of nitrogen- and sulfur-containing odorous compounds, because the properties, sulfur and nitrogen speciations are similar in PAM-conditioned sludge and raw sludge (RS). Significant increases of SO(2) and H(2)S emissions in the H(2)SO(4) conditioning process were observed due to the accelerated decomposition of sulfur-containing amino acids in acidic environment. Fenton peroxidation facilitates the formation of COS. CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. However, under strong alkaline conditions, free ammonia or protonated amine in sludge can be easily converted to volatile ammonia, resulting in a significant release of NH(3). PMID:22902143

  13. Distinct macroscopic structures developed from solutions of chemical compounds and periodic proteins

    PubMed Central

    Shiba, Kiyotaka; Honma, Takako; Minamisawa, Tamiko; Nishiguchi, Keiichi; Noda, Tetsuo

    2003-01-01

    By controlling the growth of inorganic crystals, macro-biomolecules, including proteins, play pivotal roles in modulating biomineralization. Natural proteins that promote biomineralization are often composed of simple repeats of peptide sequences; however, the relationship between these repetitive structures and their functions remains largely unknown. Here we show that an artificial protein containing a repeated peptide sequence allows NaCl, KCl, CuSO4 and sucrose to form a variety of macroscopic structures, as represented by their dendritic configurations. Mutational analyses revealed that the physicochemical characteristics of the protein, not the peptide sequence per se, were responsible for formation of the dendritic structures. This suggests that proteins that modulate crystal growth may have evolved as repeat-containing forms at a relatively high rate. These observations could serve as the basis for developing new genetic programming systems for creation of artificial proteins able to modulate crystal growth from inorganic compounds, and may thus provide a new tool for nano-biotechnology. PMID:12612603

  14. Chemical speciation and equilibria of some nucleic acid compounds and their iron(III) complexes

    NASA Astrophysics Data System (ADS)

    Masoud, Mamdouh S.; Abd El-Kaway, Marwa Y.; Hindawy, Ahmed M.; Soayed, Amina A.

    The pH effect on electronic absorption spectra of some biologically active nucleic acid constituents have been studied at room temperature and the mechanism of ionization was explained. These compounds are of two categories (pyrimidines: [barbital; 5,5'-diethyl-barbituric acid], [SBA; 4,6-dihydroxy-2-mercapto-pyrimidin], [NBA; 5-nitro-2,4,6(1H,3H,5H)-pyrimidine trione] and [TU; 2,3-dihydro-2-thioxo-pyrimidin-4(1H)-one]) and (purines: [adenine; 6-amino purine], its [Schiff bases derived from adenine-acetylacetone; (Z)-4-(7H-purin-6-ylimino)pentan-2-one) and adenine-salicylaldehyde; 2-((7H-purin-6-ylimino) methyl) phenol] and its [Azo derived from adenine-resorcinol; 4-((7H-purin-6-yl)-diazenyl) benzene-1,3-diol]. The phenomena of tautomerization assigned different tautomers. Different spectrophotometric methods are applied to evaluate the pK's values that explained with their molecular structures. The interaction of Fe3+ with some selected pyrimidines (barbital, NBA and SBA) was explained using familiar six spectrophotometric methods. The data typified the existence of different absorbing species with the different stoichiometries 1:1, 1:2, 1:3 and 2:3. The stability constant of the complexes was computed. More approach was deduced to assign the existence of different species applying the distribution diagrams.

  15. ADAPTATION OF NATURAL MICROBIAL MMUNITIES TO DEGRADATION OF XENOBIOTIC COMPOUNDS: EFFECTS OF CONCENTRATION, EXPOSURE TIME, INOCULUM, AND CHEMICAL STRUCTURE

    EPA Science Inventory

    Adaptation of microbial populations to degrade xenobiotic compounds faster after exposure to the compound was studied in eco-cores. Radiolabeled test compounds were added to cores that contained natural water and sediment samples. Adaptation was detected by comparing mineralizati...

  16. Discovery of Compounds Blocking the Proliferation of Toxoplasma gondii and Plasmodium falciparum in a Chemical Space Based on Piperidinyl-Benzimidazolone Analogs

    PubMed Central

    Saïdani, Nadia; Botté, Cyrille Y.; Deligny, Michael; Bonneau, Anne-Laure; Reader, Janette; Lasselin, Ronald; Merer, Goulven; Niepceron, Alisson; Brossier, Fabien; Cintrat, Jean-Christophe; Rousseau, Bernard; Birkholtz, Lyn-Marie; Cesbron-Delauw, Marie-France; Dubremetz, Jean-François; Mercier, Corinne; Vial, Henri; Lopez, Roman

    2014-01-01

    A piperidinyl-benzimidazolone scaffold has been found in the structure of different inhibitors of membrane glycerolipid metabolism, acting on enzymes manipulating diacylglycerol and phosphatidic acid. Screening a focus library of piperidinyl-benzimidazolone analogs might therefore identify compounds acting against infectious parasites. We first evaluated the in vitro effects of (S)-2-(dibenzylamino)-3-phenylpropyl 4-(1,2-dihydro-2-oxobenzo[d]imidazol-3-yl)piperidine-1-carboxylate (compound 1) on Toxoplasma gondii and Plasmodium falciparum. In T. gondii, motility and apical complex integrity appeared to be unaffected, whereas cell division was inhibited at compound 1 concentrations in the micromolar range. In P. falciparum, the proliferation of erythrocytic stages was inhibited, without any delayed death phenotype. We then explored a library of 250 analogs in two steps. We selected 114 compounds with a 50% inhibitory concentration (IC50) cutoff of 2 ?M for at least one species and determined in vitro selectivity indexes (SI) based on toxicity against K-562 human cells. We identified compounds with high gains in the IC50 (in the 100 nM range) and SI (up to 1,000 to 2,000) values. Isobole analyses of two of the most active compounds against P. falciparum indicated that their interactions with artemisinin were additive. Here, we propose the use of structure-activity relationship (SAR) models, which will be useful for designing probes to identify the target compound(s) and optimizations for monotherapy or combined-therapy strategies. PMID:24550329

  17. Novel chemical library screen identifies naturally occurring plant products that specifically disrupt glioblastoma-endothelial cell interactions

    PubMed Central

    Marasa, Jayne; Taylor, Sara; Jackson, Erin; Warrington, Nicole M.; Rao, Shyam; Kim, Albert H.; Leonard, Jeffrey R.; Piwnica-Worms, David; Rubin, Joshua B.

    2015-01-01

    Tumor growth is not solely a consequence of autonomous tumor cell properties. Rather, tumor cells act upon and are acted upon by their microenvironment. It is tumor tissue biology that ultimately determines tumor growth. Thus, we developed a compound library screen for agents that could block essential tumor-promoting effects of the glioblastoma (GBM) perivascular stem cell niche (PVN). We modeled the PVN with three-dimensional primary cultures of human brain microvascular endothelial cells in Matrigel. We previously demonstrated stimulated growth of GBM cells in this PVN model and used this to assay PVN function. We screened the Microsource Spectrum Collection library for drugs that specifically blocked PVN function, without any direct effect on GBM cells themselves. Three candidate PVN-disrupting agents, Iridin, Tigogenin and Triacetylresveratrol (TAR), were identified and evaluated in secondary in vitro screens against a panel of primary GBM isolates as well as in two different in vivo intracranial models. Iridin and TAR significantly inhibited intracranial tumor growth and prolonged survival in these mouse models. Together these data identify Iridin and TAR as drugs with novel GBM tissue disrupting effects and validate the importance of preclinical screens designed to address tumor tissue function rather than the mechanisms of autonomous tumor cell growth. PMID:26286961

  18. Chemical Biology Chemical Screening for Hair Cell Loss and Protection

    E-print Network

    Rubel, Edwin

    Chemical Biology Chemical Screening for Hair Cell Loss and Protection in the Zebrafish Lateral Line Rubel,1,2 and David W. Raible1,4 Abstract In humans, most hearing loss results from death of hair cells of mechanosensory hair cells. We discuss chemical screens to identify compounds that induce hair cell loss

  19. Chemical Stabilization of Soil Organic Nitrogen by Phenolic Lignin Compounds in Anaerobic Agrosystems

    NASA Astrophysics Data System (ADS)

    Olk, D. C.

    2004-12-01

    In tropical Asia, continuous cropping of paddy rice promotes the covalent binding of soil organic nitrogen (N) by phenolic lignin residues, which in turns appears to contribute to substantial long-term declines in availability of soil organic N and in grain yield. A newly developed technique of nuclear magnetic resonance spectroscopy that selects for carbon atoms bound to N was applied to a young humic fraction to directly observe an agronomically significant greater quantity of organic N (difference of 55 kg per hectare) that was bound by lignin residues in a triple-cropped rice soil compared to a nearby aerated soil. The resulting compound was an anilide. Crop residues are the parent material of soil organic matter in agricultural soils, and their anaerobic decomposition was found to slow microbially driven mineralization of both soil organic N and soil phenols during the rice season, compared to aerobic decomposition. Through use of 15N-labeled fertilizer, stabilization of soil organic N was shown to be more extensive than binding of inorganic fertilizer N. Similar results were gained in eastern Arkansas when comparing a more anaerobic continuous rice rotation to the conventional rice-soybean rotation. Future studies of covalently bound N will consider both its seasonal dynamics and its significance to long-term yield trends. Agronomic observations suggest that covalent binding of nutrients by lignin residues might also occur in other agrosystems with anaerobic decomposition of crop residues, including paddy taro in Hawaii and to a lesser extent no-tilled crops in regions with cool, wet springtime weather.

  20. Distribution of volatile organic compounds (VOCs) in surface water, soil, and groundwater within a chemical industry park in Eastern China.

    PubMed

    Liu, Benhua; Chen, Liang; Huang, Linxian; Wang, Yongseng; Li, Yuehua

    2015-01-01

    This paper focuses on the distribution of volatile organic compounds (VOCs) in the surface water, soil, and groundwater within a chemical industry park in Eastern China. At least one VOC was detected in each of the 20 sampling sites, and the maximum number of VOCs detected in the surface water, groundwater, and soil were 13, 16, and 14, respectively. Two of the 10 VOCs with elevated concentrations detected in surface water, groundwater, and soil were chloroform and 1,2-dichloroethane. The characteristics of VOCs, which include volatility, boiling point, and solubility, could significantly affect their distribution in surface water, soil, and groundwater. However, due to the direct discharging of chemical industry wastewater into surface water, higher concentrations of VOCs (except chloroform) were detected in surface water than in soil and groundwater. Fortunately, the higher volatility of VOCs prevents the VOCs from impacting groundwater, which helps to maintain a lower concentration of VOCs in the groundwater than in both surface water and soil. This is because pollutants with relatively higher boiling points and lower solubilities have higher detection frequencies in soil, and contaminants with relatively lower boiling points and higher solubilities have higher detection frequencies in water, notably in surface water. PMID:25633950

  1. National Inventory of Alkylphenol Ethoxylate Compounds in U.S. Sewage Sludges and Chemical Fate in Outdoor Soil Mesocosms

    PubMed Central

    Venkatesan, Arjun K.; Halden, Rolf U.

    2012-01-01

    We determined the first nationwide inventories of alkylphenol surfactants in U.S. sewage sludges (SS) using samples from the U.S. Environmental Protection Agency's 2001 national SS survey. Additionally, analysis of archived 3-year outdoor mesocosm samples served to determine chemical fates in SS-amended soil. Nonylphenol (NP) was the most abundant analyte (534±192 mg/kg) in SS composites, followed by its mono- and di-ethoxylates (62.1±28 and 59.5±52 mg/kg, respectively). The mean annual load of NP and its ethoxylates in SS was estimated at 2408–7149 metric tonnes, of which 1204–4289 is applied on U.S. land. NP compounds showed observable loss from SS/soil mixtures (1:2), with mean half-lives ranging from 301 to 495 days. Surfactant levels in U.S. SS ten-times in excess of European regulations, substantial releases to U.S. soils, and prolonged half-lives found under field conditions, all argue for the U.S. to follow Europe's move from 20 years ago to regulate these chemicals. PMID:23274446

  2. Field tests of polyethylene-membrane diffusion samplers for characterizing volatile organic compounds in stream-bottom sediments, Nyanza Chemical Waste Dump Superfund site, Ashland, Massachusetts

    USGS Publications Warehouse

    Lyford, Forest P.; Willey, Richard E.; Clifford, Scott

    2000-01-01

    A plume of volatile organic compounds (VOCs) in ground water extends from the Nyanza Chemical Waste Dump Superfund site in Ashland, Massachusetts, northward toward a mill pond on the Sudbury River and eastward toward the Sudbury River and former mill raceway downstream from the mill pond. Polyethylene-membrane water-to-vapor (vapor) and water-to-water (water) diffusion samplers were installed January 1999 in bottom sediments along the Sudbury River and former mill raceway in a pilot study to determine if vapor samplers would be useful in this setting for delineating a plume of contaminants in ground water near the river and raceway, to evaluate equilibration time for vapor-diffusion samplers, and to determine if diffusion samplers might be an alternative to seepage meters (inverted steel drums) and sediment sampling for evaluating concentrations of VOCs in bottom sediments. Of five tested compounds (benzene, trichloroethene, toluene, tetrachloroethene, and chlorobenzene), chlorobenzene and trichloroethene were most frequently detected in vapor from vapor-diffusion samplers. The distribution of VOCs was generally consistent with a previously mapped plume of contaminants in ground water. The field evaluation of equilibration times for vapor-diffusion samplers was inconclusive because of changing hydrologic conditions that may have affected concentrations of VOCs, possible variations in concentrations ofVOCs over short distances, and imprecise sampling and analytical methods. The limited data, however, indicated that equilibration may require 3 weeks or more in some settings. VOCs detected in samples from water-diffusion samplers and their concentrations were comparable to results from seepage meters, and VOCs detected in vapor-diffusion samplers correlated with VOCs detected in water-diffusion samplers. These results indicate that either vapor-or water-diffusion samplers would serve as an economical alternative to seepage meters for sampling of VOCs in pore water from stream-bottom sediments. Results from diffusion samplers correlated poorly with results from sediment samples, partly because of high quantitation limits for chemical analyses of sediments. In general, results from the diffusion samplers better represented the distribution of VOCs than the results from the sediment samples. This pilot study indicates that diffusion samplers are an economical means of identifying 'hotspots' for contaminants in bottom sediments and can provide insights on transport pathways for contaminants near surface-water bodies. After establishing equilibration times for a particular site, diffusion samplers also may be useful for studying variations in concentrations of VOCs over short distances, variations with time and changing hydrologic conditions, and processes such as chemical transformations by biodegradation and exchanges between surface water and ground water in the hyporheic zone.

  3. Evaluation of an evanescent fiber optic chemical sensor for monitoring aqueous volatile organic compounds

    SciTech Connect

    Blair, D.S.

    1997-04-01

    Linear chemometric algorithms were used to model the quantitative response of an evanescent fiber optic chemical sensor in aqueous mixtures with concentrations between 20 and 300 ppm. Four data sets were examined with two different experimental arrangements. Two data sets contained trichloroethene, 1,1,2 trichloroethane, and toluene. Partial Least Squares, PLS, and Principal Component Regression, PCR, algorithms performed comparably on these calibration sets with cross-validated root mean squared errors of prediction (RMSEP) for trichloroethene, 1,1,1 trichloroethane, and toluene of approximately 26, 29 and 22 ppm, respectively. The third data set contained trichloroethene, 1,1,2 trichloroethane, toluene, and chloroform and the fourth contained these four analytes as well as tetrachloroethene. Again, both chemometric algorithms performed comparably on a given data set with RMSEP for trichloroethene, 1,1,2 trichloroethane, toluene, and chloroform of approximately 6, 6, 9, and 16 ppm from the first set, and 7, 11, 13, and 31 ppm from the second set with tetrachloroethene RMSEP of 31 ppm. The decrease in the quantitative performance of the sensor for modeling toluene and chloroform upon addition of tetrachloroethene to the sample solutions is due to increased cladding absorption features in the spectral response matrix. These features overlap with the analyte absorption features of toluene and chloroform. These results suggest one of the limitations with this type of sensing format.

  4. A Pilot Chemical and Physical Stability Study of Extemporaneously Compounded Levetiracetam Intravenous Solution.

    PubMed

    Raphael, Chenzira D; Zhao, Fang; Hughes, Susan E; Juba, Katherine M

    2015-12-01

    Levetiracetam is a commonly used antiepileptic medication for tumor-related epilepsy. However, the 100 mL intravenous (IV) infusion volume can be burdensome to imminently dying hospice patients. A reduced infusion volume would improve patient tolerability. The purpose of this study was to evaluate the stability of 1000 mg/25 mL (40 mg/mL) levetiracetam IV solution in sodium chloride 0.9%. We prepared levetiracetam 40 mg/mL IV solution and added it to polyvinyl chloride (PVC) bags, polyolefin bags, and polypropylene syringes. Triplicate samples of each product were stored at refrigeration (2-8°C) and analyzed on days 0, 1, 4, 7, and 14. Samples were subjected to visual inspection, pH measurement, and stability-indicating high-performance liquid chromatography (HPLC) analysis. Over the 2-week storage period, there was no significant change in visual appearance or pH for any of the stability samples. The HPLC results confirmed that all stability samples retained 94.2-101.3% of initial drug concentration and no degradation products or leachable material from the packaging materials were observed. We conclude that levetiracetam 1000 mg/25 mL IV solution in sodium chloride 0.9% is physically and chemically stable for up to 14 days under refrigeration in polypropylene syringes, PVC bags, and polyolefin bags. PMID:26654410

  5. Data Analysis of Multi-Laser Standoff Spectral identification of chemical and biological compounds

    SciTech Connect

    Farahi, R H; Zaharov, Viktor; Tetard, Laurene; Thundat, Thomas George; Passian, Ali

    2013-01-01

    With the availability of tunable broadband coherent sources that emit mid-infrared radiation with well-defined beam characteristics, spectroscopies that were traditionally not practical for standoff detection1 or for develop- ment of miniaturized infrared detectors2, 3 have renewed interest. While obtaining compositional information for objects from a distance remains a major challenge in chemical and biological sensing, recently we demonstrated that capitalizing on mid-infrared excitation of target molecules by using quantum cascade lasers and invoking a pump probe scheme can provide spectral fingerprints of substances from a variable standoff distance.3 However, the standoff data is typically associated with random fluctuations that can corrupt the fine spectral features and useful data. To process the data from standoff experiments toward better recognition we consider and apply two types of denoising techniques, namely, spectral analysis and Karhunen-Loeve Transform (KLT). Using these techniques, infrared spectral data have been effectively improved. The result of the analysis illustrates that KLT can be adapted as a powerful data denoising tool for the presented pump-probe infrared standoff spectroscopy.

  6. Chemical synthesis of battery grade super-iron barium and potassium Fe(VI) ferrate compounds

    NASA Astrophysics Data System (ADS)

    Licht, Stuart; Naschitz, Vera; Liu, Bing; Ghosh, Susanta; Halperin, Nadezhda; Halperin, Leonid; Rozen, Dmitri

    The chemical preparation of high purity potassium and barium ferrates for alkaline electrochemical storage are presented. The synthesized salts are used to demonstrate a variety of high capacity super-iron (Zn anode) alkaline AAA cell configurations which utilize these Fe(V) salts. Results of 500 days, full stability, of the synthesized K 2FeO 4 are presented. Synthetic pathways yielding 80-100 g of 96.5-99.5% pure K 2FeO 4 and BaFeO 4 are presented, and the products of these syntheses are demonstrated to provide a high energy electrochemical discharge in a variety of AAA alkaline cells. BaFeO 4 super-iron alkaline AAA cells provide over 0.8 W h during 2.8 ? discharge, yielding over 200% higher capacity than conventional alkaline batteries. The barium super-iron cell configurations studied provide higher capacity than the potassium super-iron alkaline cell configurations studied.

  7. Electrochemical stabilization of porous silicon multilayers for sensing various chemical compounds

    NASA Astrophysics Data System (ADS)

    Salem, M. S.; Sailor, M. J.; Harraz, F. A.; Sakka, T.; Ogata, Y. H.

    2006-10-01

    Porous silicon rugate filters are fabricated and investigated for their ability to sense chemical species. The durability of the filter is tested by allowing the structure to undergo many cycles of adsorption and desorption of vapor-phase ethanol molecules. The characteristic reflectivity peak of the structure exhibits a relative blueshift of 2.7% after 86 adsorption/desorption cycles. The observed shift is ascribed to the formation of silicon dioxide, which has a lower refractive index than that of silicon. In order to stabilize the structure against oxidation expected from cycling and environmental exposure, the filter is subjected to electrochemical oxidation in an aqueous sulfuric acid electrolyte. The treatment dramatically improves stability of the sensor; a relative blueshift of <0.4% is observed after 100 adsorption/desorption cycles for this sensor. The sensitivity of the sensor is also affected by electrochemical oxidation: the response to saturated ethanol in air changes from ?? =100nm to ?? =70nm, respectively. Theoretical calculations using the Bruggeman effective medium approximation and the characteristic matrix method indicate that up to 15% (by volume) of silicon is transformed to silicon dioxide by the electrochemical oxidation procedure. This volume ratio is close to that estimated from Auger electron spectroscopy measurements.

  8. High-Throughput Assay for Modulators of Mitochondrial Membrane Potential Identifies a Novel Compound With Beneficial Effects on db/db Mice

    PubMed Central

    Qiu, Bei-Ying; Turner, Nigel; Li, Yuan-Yuan; Gu, Min; Huang, Meng-Wei; Wu, Fang; Pang, Tao; Nan, Fa-Jun; Ye, Ji-Ming; Li, Jing-Ya; Li, Jia

    2010-01-01

    OBJECTIVE Recently, several drugs have been shown to exert beneficial effects for metabolic syndrome through mild regulation of mitochondrial function. Hence, we explored a strategy of targeting mitochondrial function to improve glucose and lipid metabolism. RESEARCH DESIGN AND METHODS Mitochondrial membrane potential (??m) is a marker of mitochondrial function; therefore, we set up a high-throughput screening assay of ??m in L6 myotubes. The effects of a selected lead compound were investigated in vitro and in vivo in relation to metabolic syndrome. RESULTS A novel small-molecule compound, C1, was identified through this high-throughput screening. C1 depolarized ??m in L6 myotubes without cytotoxicity and led to increased cellular AMP-to-ATP ratio, activation of AMP-activated protein kinase (AMPK), and enhanced glucose uptake. It also stimulated the AMPK pathway in HepG2 cells, leading to decreased lipid content. Intriguingly, C1 inhibited respiration in L6 myotubes but did not affect respiration in isolated muscle mitochondria, suggesting that it may depolarize ??m indirectly by affecting the supply of electron donors. Acute administration of C1 in C57BL/6J mice markedly increased fat oxidation and the phosphorylation of AMPK and acetyl-CoA carboxylase in the liver. In diabetic db/db mice, chronic administration of C1 significantly reduced hyperglycemia, plasma fatty acids, glucose intolerance, and the mRNA levels of phosphoenolpyruvate carboxykinase and glucose-6-phosphatase in the liver. CONCLUSIONS Our results demonstrate a novel small molecule that mildly depolarizes ??m and is able to improve glucose and lipid metabolism to exert beneficial effects for metabolic syndrome. These findings suggest that compounds regulating mitochondrial function may have therapeutic potential for type 2 diabetes. PMID:19833880

  9. The cell competition-based high-throughput screening identifies small compounds that promote the elimination of RasV12-transformed cells from epithelia.

    PubMed

    Yamauchi, Hajime; Matsumaru, Takanori; Morita, Tomoko; Ishikawa, Susumu; Maenaka, Katsumi; Takigawa, Ichigaku; Semba, Kentaro; Kon, Shunsuke; Fujita, Yasuyuki

    2015-01-01

    Recent studies have revealed that cell competition can occur between normal and transformed epithelial cells; normal epithelial cells recognize the presence of the neighboring transformed cells and actively eliminate them from epithelial tissues. Here, we have established a brand-new high-throughput screening platform that targets cell competition. By using this platform, we have identified Rebeccamycin as a hit compound that specifically promotes elimination of RasV12-transformed cells from the epithelium, though after longer treatment it shows substantial cytotoxic effect against normal epithelial cells. Among several Rebeccamycin-derivative compounds, we have found that VC1-8 has least cytotoxicity against normal cells but shows the comparable effect on the elimination of transformed cells. This cell competition-promoting activity of VC1-8 is observed both in vitro and ex vivo. These data demonstrate that the cell competition-based screening is a promising tool for the establishment of a novel type of cancer preventive medicine. PMID:26480891

  10. The cell competition-based high-throughput screening identifies small compounds that promote the elimination of RasV12-transformed cells from epithelia

    PubMed Central

    Yamauchi, Hajime; Matsumaru, Takanori; Morita, Tomoko; Ishikawa, Susumu; Maenaka, Katsumi; Takigawa, Ichigaku; Semba, Kentaro; Kon, Shunsuke; Fujita, Yasuyuki

    2015-01-01

    Recent studies have revealed that cell competition can occur between normal and transformed epithelial cells; normal epithelial cells recognize the presence of the neighboring transformed cells and actively eliminate them from epithelial tissues. Here, we have established a brand-new high-throughput screening platform that targets cell competition. By using this platform, we have identified Rebeccamycin as a hit compound that specifically promotes elimination of RasV12-transformed cells from the epithelium, though after longer treatment it shows substantial cytotoxic effect against normal epithelial cells. Among several Rebeccamycin-derivative compounds, we have found that VC1-8 has least cytotoxicity against normal cells but shows the comparable effect on the elimination of transformed cells. This cell competition-promoting activity of VC1-8 is observed both in vitro and ex vivo. These data demonstrate that the cell competition-based screening is a promising tool for the establishment of a novel type of cancer preventive medicine. PMID:26480891

  11. Use of medaka (Oryzias latipes) as a model teleost to identify reproductive endpoints indicative of exposure to endocrine disrupting chemicals

    SciTech Connect

    Papoulias, D.M.; Tillitt, D.; Jones, S.; Noltie, D.

    1995-12-31

    The purpose of this research is to identify effects of endocrine disrupting chemicals on the reproductive system of fish at various stages of sexual differentiation and development. The model teleost used was the d-rR strain of medaka (Oryzias latipes) which has a heritable sex-linked color gene. In medaka, sex differences are first detected at the cellular level at hatch. In males, the mitotic activity of the primordial germ cells (PGC) is arrested while the PGCs of the females continue to divide. The germ cells of the gonochoristic medaka have been demonstrated to be totipotent with respective to gonia production. Because endogenous sex steroid hormones are believed to regulate this early process of sexual differentiation, the authors have hypothesized that mitotic activity in males and females exposed to endocrine disrupting chemicals will be different than unexposed individuals. Results are presented for tests conducted by injecting medaka eggs within 36 hours post-hatch with 3 doses of 2,3,7,8-TCDD (nominally 2.3, 1.3, 0.2 pg/embryo), a known anti-estrogen, dissolved in triolein.

  12. Predominant chemicals in Hanford site waste tanks

    SciTech Connect

    Boothe, G.F.

    1996-09-23

    Predominant chemical constituents in Hanford Site single-shell and double-shell tanks are determined. Predominant chemical constituents are defined as those anions, cations, and compounds presenting over 99 percent of the routine risks to workers or members of the public. Toxic chemicals and those chemical constituents in tanks that present the 99 percentile hazards to groundwater and air are identified.

  13. Susceptibility of helminth species from horses against different chemical compounds in Brazil.

    PubMed

    Felippelli, Gustavo; Cruz, Breno Cayeiro; Gomes, Lucas Vinicius Costa; Lopes, Welber Daniel Zanetti; Teixeira, Weslen Fabrício Pires; Maciel, Willian Giquelin; Buzzulini, Carolina; Bichuette, Murilo Abud; Campos, Gabriel Pimentel; Soares, Vando Edésio; Bergamasco, Paula Luzia Formigoni; Oliveira, Gilson Pereira de; Costa, Alvimar José da

    2015-09-15

    By means of parasitological necropsies, the present study aimed to evaluate, in six experiments, the degree of susceptibility or resistance of different helminth species which naturally infect horses to ivermectin 0.2mg/kg, abamectin 0.2mg/kg, moxidectin 0.4mg/kg, trichlorfon 35mg/kg, ivermectin 0.2mg/kg+praziquantel 2.5mg/kg, abamectin 0.2mg/kg+praziquantel 2.5mg/kg and ivermectin 0.2mg/kg+6.6 mg/kg pyrantel. At experimental day zero, the horses were allocated to treatment groups based on average counts of strongylid eggs per gram of feces (EPG) obtained on days -3, -2 and -1. Oxyuris sp. infections were confirmed as positive or negative. All the animals in the six experiments were naturally infected by this helminth species. Each group (control or treated) consisted of six animals. All the assessed Habronema muscae populations analyzed were susceptible to ivermectin, abamectin and moxidectin. Of the six Trichostrongylus axei populations, four were susceptible to ivermectin, abamectin, moxidectin, trichlorfon and ivermectin+praziquantel, and two were resistant to abamectin+praziquantel and ivermectin+pyrantel. Both Strongyloides westeri populations analyzed were susceptible to ivermectin, abamectin, moxidectin and abamectin+praziquantel. For O. equi, resistance was found in four different populations treated with ivermectin, abamectin, moxidectin, trichlorfon and ivermectin+praziquantel. Only combinations of abamectin+praziquantel and ivermectin+pyrantel were effective against this parasite species. All the large strongyles diagnosed in the present study (Strongyus edentatus, Strongyus vulgaris and Triodontophorus serratus) were susceptible to all the chemicals tested, with the exception of trichlorfon. Of the Cyathostominae populations, one was diagnosed as resistant to ivermectin and another to trichlorfon. The remaining populations from this nematode group were considered to be sensitive to ivermectin, abamectin, moxidectin, ivermectin+praziquantel, abamectin+praziquantel and ivermectin+pyrantel. New studies should be performed in different regions to evaluate the efficacy of trichlorfon in others field populations of helminthes. PMID:26277565

  14. Photocatalytic and chemical oxidation of organic compounds in supercritical carbon dioxide. Progress report for FY97

    SciTech Connect

    Blake, D.M.; Bryant, D.L.; Reinsch, V.

    1997-09-30

    'The background for the project is briefly reviewed and the work done during the nine months since funding was received is documented. Work began in January, 1997. A post doctoral fellow joined the team in April. The major activities completed this fiscal year were: staffing the project, design of the experimental system, procurement of components, assembly of the system. preparation of the Safe Operating Procedure and ES and H compliance, pressure testing, establishing data collection and storage methodology, and catalyst preparation. Objective The objective of the project is to develop new chemistry for the removal of organic contaminants from supercritical carbon dioxide. This has application in processes used for continuous cleaning and extraction of parts and waste materials. A secondary objective is to increase the fundamental understanding of photocatalytic chemistry. Cleaning and extraction using supercritical carbon dioxide (scCO{sub 2}) can be applied to the solution of a wide range of environmental and pollution prevention problems in the DOE complex. Work is being done that explores scCO{sub 2} in applications ranging from cleaning contaminated soil to cleaning components constructed from plutonium. The rationale for use of scCO{sub 2} are based on the benign nature, availability and low cost, attractive solvent properties, and energy efficient separation of the extracted solute from the solvent by moderate temperature or pressure changes. To date, R and D has focussed on the methods and applications of the extraction steps of the process. Little has been done that addresses methods to polish the scCO{sub 2} for recycle in the cleaning or extraction operations. In many applications it will be desirable to reduce the level of contamination from that which would occur at steady state operation of a process. This proposal addresses chemistry to achieve that. This would be an alternative to removing a fraction of the contaminated scCO{sub 2} for disposal and using makeup scCO{sub 2}. A chemical polishing operation can reduce the release of CO{sub 2} from the process. It can also reduce the consumption of reagents that may be used in the process to enhance extraction and cleaning. A polishing operation will also reduce or avoid formation of an additional waste stream. Photocatalytic and other photochemical oxidation chemistry have not been investigated in scCO{sub 2}. The large base of information for these reactions in water, organic solvents, or air suggest that the chemistry will work in carbon dioxide. There are compelling reasons to believe that the properties of scCO{sub 2} should increase the performance of photocatalytic chemistry over that found in more conventional fluid phases.'

  15. Measurements of Oxidized Organic Compounds during SOAS 2013 using nitrate ion chemical ionization coupled with High Resolution Time-of-Flight Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Massoli, P.; Stark, H.; Cnagaratna, M.; Junninen, H.; Hakala, J. P.; Mauldin, R.; Ehn, M.; Sipila, M.; Krechmer, J.; Kimmel, J.; Jimenez, J. L.; Jayne, J. T.; Worsnop, D. R.

    2013-12-01

    We present ambient measurements of gaseous organic compounds by means of a High Resolution Time-of-Flight Chemical Ionization Mass Spectrometry (HR-ToF-CIMS) using nitrate ion (NO3-) chemistry. This technique allows to selectively detect oxidized gas-phase species, e.g., oxidized organic molecules and sulfuric acid via clustering with NO3- and its high order clusters. The capability of making such measurements is important because both sulfuric acid and organic gas molecules have a recognized key role in new particle formation (NPF) processes and likely have an important role in particulate phase chemistry and formation of secondary organic aerosols (SOA). The HR-ToF-CIMS was deployed during the Southern Oxidant and Aerosol Study (SOAS) at the forest supersite in Centreville, AL, from June 1 to July 15, 2013. The main goal of the SOAS campaign was to investigate the composition and sources of SOA in the Southeast US, where emissions are mainly represented by biogenic volatile organic compounds (BVOC) emissions and in less extent by anthropogenic emissions (AVOC). During SOAS, the HR-ToF-CIMS detected a range of organic ions that based on previous literature could be identified as oxidation products of both isoprene and terpenes. The isoprene products were 5 to 10 times more abundant than the terpene products. The isoprene-related molecules showed a diurnal cycle with a day time peak, typically after 1500 local time, while the terpene products were higher at night (between 2000 and 0600 local time). These results are consistent with the diurnal trends of primary BVOC emissions from other co-located instruments. The ambient data are also compared to laboratory measurements where oxidized organic vapors are produced using a Potential Aerosol Mass (PAM) flow reactor by the OH oxidation of biogenic gas-phase precursors (isoprene, a-pinene) over multiple days of equivalent atmospheric exposure.

  16. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2003-01-01

    Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

  17. 40 CFR 721.5250 - Trimethyl spiropolyheterocyclic naphthalene compound.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...subject to reporting. (1) The chemical substance identified generically as trimethyl spir-o-poly-het-er-o-cyc-lic naphthalene compound (PMN P-91-1456) is subject to reporting under this section for the significant new uses...

  18. 40 CFR 721.5250 - Trimethyl spiropolyheterocyclic naphthalene compound.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...subject to reporting. (1) The chemical substance identified generically as trimethyl spir-o-poly-het-er-o-cyc-lic naphthalene compound (PMN P-91-1456) is subject to reporting under this section for the significant new uses...

  19. 40 CFR 721.5250 - Trimethyl spiropolyheterocyclic naphthalene compound.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...subject to reporting. (1) The chemical substance identified generically as trimethyl spir-o-poly-het-er-o-cyc-lic naphthalene compound (PMN P-91-1456) is subject to reporting under this section for the significant new uses...

  20. 40 CFR 721.5250 - Trimethyl spiropolyheterocyclic naphthalene compound.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...subject to reporting. (1) The chemical substance identified generically as trimethyl spir-o-poly-het-er-o-cyc-lic naphthalene compound (PMN P-91-1456) is subject to reporting under this section for the significant new uses...

  1. 40 CFR 721.5250 - Trimethyl spiropolyheterocyclic naphthalene compound.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...subject to reporting. (1) The chemical substance identified generically as trimethyl spir-o-poly-het-er-o-cyc-lic naphthalene compound (PMN P-91-1456) is subject to reporting under this section for the significant new uses...

  2. The conversion of solar energy to the chemical energy of organic compounds is a complex process that includes electron transport and

    E-print Network

    Ehleringer, Jim

    The conversion of solar energy to the chemical energy of organic compounds is a complex process discussions of the photochemical and biochemical reactions of pho- tosynthesis should not overshadow the fact- pend strongly on prevailing photosynthetic rates in a dynamic en- vironment. To the ecologist, the fact

  3. Advances in X-Ray Chemical Analysis, Japan, 41 (2010) ISSN 0911-7806 Analysis of Compound Ratios of Titanium Dioxides with

    E-print Network

    Jun, Kawai

    2010-01-01

    Advances in X-Ray Chemical Analysis, Japan, 41 (2010) ISSN 0911-7806 © X Analysis of Compound Ratios of Titanium Dioxides with Various Crystallite Sizes Using X-Ray Diffraction Broadenings Hiroya MIYAUCHI, Hiroshi KITAGAKI, Tomohiko NAKAMURA, Sadahiro NAKANISHI and Jun KAWAI #12;#12;41 75 X Adv. X-Ray

  4. In-situ Real-Time Monitoring of Volatile Organic Compound Exposure and Heart Rate Variability for Patients with Multiple Chemical Sensitivity.

    PubMed

    Mizukoshi, Atsushi; Kumagai, Kazukiyo; Yamamoto, Naomichi; Noguchi, Miyuki; Yoshiuchi, Kazuhiro; Kumano, Hiroaki; Sakabe, Kou; Yanagisawa, Yukio

    2015-01-01

    In-situ real-time monitoring of volatile organic compound (VOC) exposure and heart rate variability (HRV) were conducted for eight multiple chemical sensitivity (MCS) patients using a VOC monitor, a Holter monitor, and a time-activity questionnaire for 24 h to identify the relationship between VOC exposure, biological effects, and subjective symptoms in actual life. The results revealed no significantly different parameters for averaged values such as VOC concentration, HF (high frequency), and LF (low frequency) to HF ratio compared with previous data from healthy subjects (Int. J. Environ. Res. Public Health 2010, 7, 4127-4138). Significant negative correlations for four subjects were observed between HF and amounts of VOC change. These results suggest that some patients show inhibition of parasympathetic activities along with VOC exposure as observed in healthy subjects. Comparing the parameters during subjective symptoms and normal condition, VOC concentration and/or VOC change were high except for one subject. HF values were low for five subjects during subjective symptoms. Examining the time-series data for VOC exposure and HF of each subject showed that the subjective symptoms, VOC exposure, and HF seemed well related in some symptoms. Based on these characteristics, prevention measures of symptoms for each subject may be proposed. PMID:26445055

  5. In-situ Real-Time Monitoring of Volatile Organic Compound Exposure and Heart Rate Variability for Patients with Multiple Chemical Sensitivity

    PubMed Central

    Mizukoshi, Atsushi; Kumagai, Kazukiyo; Yamamoto, Naomichi; Noguchi, Miyuki; Yoshiuchi, Kazuhiro; Kumano, Hiroaki; Sakabe, Kou; Yanagisawa, Yukio

    2015-01-01

    In-situ real-time monitoring of volatile organic compound (VOC) exposure and heart rate variability (HRV) were conducted for eight multiple chemical sensitivity (MCS) patients using a VOC monitor, a Holter monitor, and a time-activity questionnaire for 24 h to identify the relationship between VOC exposure, biological effects, and subjective symptoms in actual life. The results revealed no significantly different parameters for averaged values such as VOC concentration, HF (high frequency), and LF (low frequency) to HF ratio compared with previous data from healthy subjects (Int. J. Environ. Res. Public Health 2010, 7, 4127–4138). Significant negative correlations for four subjects were observed between HF and amounts of VOC change. These results suggest that some patients show inhibition of parasympathetic activities along with VOC exposure as observed in healthy subjects. Comparing the parameters during subjective symptoms and normal condition, VOC concentration and/or VOC change were high except for one subject. HF values were low for five subjects during subjective symptoms. Examining the time-series data for VOC exposure and HF of each subject showed that the subjective symptoms, VOC exposure, and HF seemed well related in some symptoms. Based on these characteristics, prevention measures of symptoms for each subject may be proposed. PMID:26445055

  6. Chemical and electronic structure of surfaces and interfaces in compound semiconductors

    NASA Astrophysics Data System (ADS)

    Pookpanratana, Sujitra

    The interface formation between two different materials is important in applications for optoelectronic devices. Often, the success or performance of these devices is dependent on the formation of these heterojunctions. In this work, the surface and interfaces in such materials for optoelectronic devices are investigated by a suite of X-ray analytical techniques including X-ray photoelectron (XPS), X-ray excited Auger electron (XAES), and X-ray emission (XES) spectroscopies to provide novel insight. For the group III-nitrides (e.g., AlxGa 1-xN) used in many light emitting devices, a significant challenge exists to form an Ohmic contact. The electron affinities and band gaps of GaN and AlN are different, and thus it is difficult to find one contact scheme compatible for the entire AlxGa1-xN system. Contact schemes are empirically derived such that they result in optimal electrical properties, and thus this work focuses on providing a deeper understanding of the empirically derived contact-schemes. For the n-doped alloys, the presence of VN was identified at the V-AlxGa1-xN interface after contact formation. The amount of VN present varied for n-GaN and n-AlN, and was indicative of the VN dependency of the n-AlxGa1-xN composition. These findings provide detailed insight into the contact formation of (Al,Ga)N-based devices and the performance of V-based contacts. Next generation thin film solar cells based on CdS/Cu(In,Ga)Se2 and CdTe/CdS heterojunctions, which are expected to replace the current Si-based technologies within a decade, are constantly driven to improve their device efficiencies. However, to optimize the entire device, the interfaces and layers within such a device must be understood. The interface formation between high-efficiency Cu(In,Ga)Se2 absorbers and CdS buffer layer was followed, and the findings suggest the presence of a S-containing interlayer between Cu(In,Ga)Se2 and CdS. For CdTe/CdS solar cells, post-absorber deposition processing (CdCl2 activation and back contact treatment) is necessary. The findings demonstrate that the CdCl2 activation drives the sulfur atoms from the CdS layer towards the back contact. While both of the processing steps influence the morphology of the back contact, the spectroscopic results suggest that the CdCl2 activation has a larger impact on the surface and interface composition involved in CdTe solar cells. The surface and interface structure are complex in these optoelectronic devices, and they are expected to influence the electrical properties (and thus performance) of the final device. The goal of this dissertation is to provide new insight and physical explanations which could aid in future optimization and designs of heterojunctions.

  7. Use of thermal desorption gas chromatography-olfactometry/mass spectrometry for the comparison of identified and unidentified odor active compounds emitted from building products containing linseed oil.

    PubMed

    Clausen, P A; Knudsen, H N; Larsen, K; Kofoed-Sørensen, V; Wolkoff, P; Wilkins, C K

    2008-11-14

    The emission of odor active volatile organic compounds (VOCs) from a floor oil based on linseed oil, the linseed oil itself and a low-odor linseed oil was investigated by thermal desorption gas chromatography combined with olfactometry and mass spectrometry (TD-GC-O/MS). The oils were applied to filters and conditioned in the micro emission cell, FLEC, for 1-3days at ambient temperature, an air exchange rate of 26.9h(-1) and a 30% relative humidity. These conditions resulted in dynamic headspace concentrations and composition of the odor active VOCs that may be similar to real indoor setting. Emission samples for TD-GC-O/MS analysis from the FLEC were on Tenax TA. Although many volatile VOCs were detected by MS, only the odor active VOCs are reported here. In total, 142 odor active VOCs were detected in the emissions from the oils. About 50 of the odor active VOCs were identified or tentatively identified by GC-MS. While 92 VOCs were detected from the oil used in the floor oil, only 13 were detected in the low-odor linseed oil. The major odor active VOCs were aldehydes and carboxylic acids. Spearmen rank correlation of the GC-O profiles showed that the odor profile of the linseed oil likely influenced the odor profile of the floor oil based on this linseed oil. PMID:18922536

  8. Identification of adducts between an odoriferous volatile thiol and oxidized grape phenolic compounds: kinetic study of adduct formation under chemical and enzymatic oxidation conditions.

    PubMed

    Nikolantonaki, Maria; Jourdes, Michael; Shinoda, Kentaro; Teissedre, Pierre-Louis; Quideau, Stéphane; Darriet, Philippe

    2012-03-14

    HPLC-MS and (1)H, (13)C, and 2D NMR analyses were used to identify new addition products between 3-sulfanylhexan-1-ol (3SH) and o-quinones derived from (+)-catechin, (-)-epicatechin, and caftaric acid. The kinetics of formation of these adducts were monitored in a wine model solution and in a must-like medium by HPLC-UV-MS with the aim of understanding the chemical mechanism involved in reactions between volatile thiols and o-quinones. One o-quinone-caftaric acid/3SH adduct, three o-quinone-(+)-catechin/3SH adducts, and three o-quinone-(-)-epicatechin/3SH adducts were characterized. Caftaric acid was oxidized faster than (-)-epicatechin and (+)-catechin when these phenolic compounds were incubated in a one-component mixture with polyphenoloxidase (PPO) in the presence of 3SH. Consequently, o-quinone-caftaric acid formed adducts with 3SH more rapidly than o-quinone-(+)-catechin and o-quinone-(-)-epicatechin in the absence of other nucleophilic species. Furthermore, o-quinone-(-)-epicatechin reacted faster than o-quinone-(+)-catechin with 3SH. Sulfur dioxide decreased the yield of adduct formation to a significant extent. Under chemical oxidation conditions, the rates and yields of adduct formation were lower than those observed in the presence of PPO, and o-quinone-caftaric acid was slightly less reactive with 3SH, compared to oxidized flavan-3-ols. The identification of o-quinone-caftaric acid/3SH and o-quinone-(+)-catechin/3SH adducts in a must matrix suggests that the proposed reaction mechanism is responsible for 3SH loss in dry wines during their vinification and aging process. PMID:22324817

  9. Chemical Library Screening and Structure-Function Relationship Studies Identify Bisacodyl as a Potent and Selective Cytotoxic Agent Towards Quiescent Human Glioblastoma Tumor Stem-Like Cells

    PubMed Central

    Mameri, Samir; Dong, Jihu; Salomé, Christophe; Chen, Wanyin; El-Habr, Elias A.; Bousson, Fanny; Sy, Mohamadou; Obszynski, Julie; Boh, Alexandre; Villa, Pascal; Assad Kahn, Suzana; Didier, Bruno; Bagnard, Dominique; Junier, Marie-Pierre; Chneiweiss, Hervé; Haiech, Jacques; Hibert, Marcel; Kilhoffer, Marie-Claude

    2015-01-01

    Cancer stem-like cells reside in hypoxic and slightly acidic tumor niches. Such microenvironments favor more aggressive undifferentiated phenotypes and a slow growing "quiescent state" which preserves them from chemotherapeutic agents that essentially target proliferating cells. Our objective was to identify compounds active on glioblastoma stem-like cells, including under conditions that mimick those found in vivo within this most severe and incurable form of brain malignancy. We screened the Prestwick Library to identify cytotoxic compounds towards glioblastoma stem-like cells, either in a proliferating state or in more slow-growing "quiescent" phenotype resulting from non-renewal of the culture medium in vitro. Compound effects were assessed by ATP-level determination using a cell-based assay. Twenty active molecules belonging to different pharmacological classes have thus been identified. Among those, the stimulant laxative drug bisacodyl was the sole to inhibit in a potent and specific manner the survival of quiescent glioblastoma stem-like cells. Subsequent structure-function relationship studies led to identification of 4,4'-dihydroxydiphenyl-2-pyridyl-methane (DDPM), the deacetylated form of bisacodyl, as the pharmacophore. To our knowledge, bisacodyl is currently the only known compound targeting glioblastoma cancer stem-like cells in their quiescent, more resistant state. Due to its known non-toxicity in humans, bisacodyl appears as a new potential anti-tumor agent that may, in association with classical chemotherapeutic compounds, participate in tumor eradication. PMID:26270679

  10. Impact of the chemical and physical stability of ketoprofen compounded in various pharmaceutical bases on its topical and transdermal delivery.

    PubMed

    Nornoo, Adwoa O; Wulz, Jordan; Yoon, Haena; Nan, Yu; Lese, Michele

    2014-11-28

    Abstract Increasing demands for individualized drug treatment has led to an increase in the practice of compounded medications. In this study, we determined the impact of the chemical and physical stability of ketoprofen (10%w/w) cream on its topical/transdermal delivery over a 6-month period. The shelf life of ketoprofen at 25?°C in the pharmaceutical bases LipoDerm and LipoBase (109.94 and 85.9 days) was significantly longer than that in Pluronic Lecithin Organogel (PLO; 44.81 days), justifying extending its beyond use date (BUD) from 30 (USP37/NF32) to at least 60 days in LipoDerm and LipoBase. All the creams evaluated exhibited shear-thinning flow behavior with moderate thixotropy, while the flow properties for LipoBase and PLO creams were altered at storage times greater than 90 days. The percentage of ketoprofen permeated through porcine ear skin was 13.7, 19.1 and 12.7% of the dose from LipoDerm, LipoBase and PLO, respectively and decreased 2- to 3-fold after 28 days of storage. Flux ranging from 85.3 to 446.7?µg/cm(2)/h and topical delivery, on the other hand, were not influenced by storage duration past 28 days. In conclusion, this study justifies extending the BUD of ketoprofen in LipoDerm and LipoBase to 60 days if used for topical delivery only. PMID:25431959

  11. Simultaneous determination of 13 chemical marker compounds in Gwakhyangjeonggi-san, a herbal formula, with validated analytical methods.

    PubMed

    Kim, Jung-Hoon; Shin, Hyeun-Kyoo; Seo, Chang-Seob

    2014-01-01

    This study was designed for simultaneous determination of 13 chemical marker compounds, namely, protocatechuic acid, chlorogenic acid, caffeic acid, liquiritin, hesperidin, apigetrin, rosmarinic acid, oxypeucedanin hydrate, byakangelicin, apigenin, glycyrrhizin, nobiletin, and 6-gingerol in Gwakhyangjeonggi-san (GJS: Huoxiang-zhengqi-san in Chinese). A quantitative analytical method was developed based on HPLC-PDA with validation in terms of precision, accuracy, and repeatability, and successfully employed for quality evaluation of GJS samples with the help of chemometric techniques such as principal component analysis (PCA) and hierarchical clustering analysis (HCA). The correlation coefficient for the linear regression was > 0.9994. The intra-day and inter-day precision was < 3.0% of the relative standard deviation (RSD) value, and the recovery was in the range 92.5-107.0%, with RSD values < 4.0%, and the repeatability was < 3.0% of RSD. Variations in the quantity were observed in GJS products from different origins, which were classified by PCA and HCA. The quantitative and chemometric analyses indicate the necessity for consistency in GJS production for the purpose of quality control. PMID:24660465

  12. TOXICOGENOMIC STUDY OF TRIAZOLE FUNGICIDES AND PERFLUOROALKYL ACIDS IN RAT LIVERS ACCURATELY CATEGORIZES CHEMICALS AND IDENTIFIES MECHANISMS OF TOXICITY

    EPA Science Inventory

    Toxicogenomic analysis of five environmental chemicals was performed to investigate the ability of genomics to predict toxicity, categorize chemicals, and elucidate mechanisms of toxicity. Three triazole antifungals (myclobutanil, propiconazole, and triadimefon) and two perfluori...

  13. Identifying developmental toxicity pathways for a subset of ToxCast chemicals using human embryonic stem cells and metabolomics

    EPA Science Inventory

    Metabolomics analysis was performed on the supernatant of human embryonic stem (hES) cell cultures exposed to a blinded subset of 11 chemicals selected from the chemical library of EPA's ToxCast™ chemical screening and prioritization research project. Metabolites from hES cultur...

  14. An array of Escherichia coli clones over-expressing essential proteins: A new strategy of identifying cellular targets of potent antibacterial compounds

    SciTech Connect

    Xu, H. Howard . E-mail: hxu3@calstatela.edu; Real, Lilian; Bailey, Melissa Wu

    2006-11-03

    With the advancement of high throughput screening, it has become easier and faster to discover hit compounds that inhibit proliferation of bacterial cells. However, development in technologies used to identify cellular targets of potent antibacterial inhibitors has lagged behind. Here, we describe a novel strategy of target identification for antibacterial inhibitors using an array of Escherichia coli clones each over-expressing one essential protein. In a proof-of-concept study, eight essential genes were cloned into pLex5BA vector under the control of an inducible promoter. Over-expression of target proteins was confirmed. For two clones, one over-expressing FabI and the other over-expressing MurA enzymes, the host cells became 17- and 139-fold more resistant to the specific inhibitors triclosan and phosphomycin, respectively, while the susceptibility of other clones towards these inhibitors remained unchanged after induction of gene expression. Target identification via target protein over-expression was demonstrated using both mixed clone and individual clone assay formats.

  15. Aspherical-atom modeling of coordination compounds by single-crystal X-ray diffraction allows the correct metal atom to be identified.

    PubMed

    Dittrich, Birger; Wandtke, Claudia M; Meents, Alke; Pröpper, Kevin; Mondal, Kartik Chandra; Samuel, Prinson P; Amin Sk, Nurul; Singh, Amit Pratap; Roesky, Herbert W; Sidhu, Navdeep

    2015-02-01

    Single-crystal X-ray diffraction (XRD) is often considered the gold standard in analytical chemistry, as it allows element identification as well as determination of atom connectivity and the solid-state structure of completely unknown samples. Element assignment is based on the number of electrons of an atom, so that a distinction of neighboring heavier elements in the periodic table by XRD is often difficult. A computationally efficient procedure for aspherical-atom least-squares refinement of conventional diffraction data of organometallic compounds is proposed. The iterative procedure is conceptually similar to Hirshfeld-atom refinement (Acta Crystallogr. Sect. A- 2008, 64, 383-393; IUCrJ. 2014, 1,61-79), but it relies on tabulated invariom scattering factors (Acta Crystallogr. Sect. B- 2013, 69, 91-104) and the Hansen/Coppens multipole model; disordered structures can be handled as well. Five linear-coordinate 3d metal complexes, for which the wrong element is found if standard independent-atom model scattering factors are relied upon, are studied, and it is shown that only aspherical-atom scattering factors allow a reliable assignment. The influence of anomalous dispersion in identifying the correct element is investigated and discussed. PMID:25393218

  16. Relationship between gas chromatographic retention indices and chemical shifts in the 13C NMR spectra of structural isomers of compounds of tetracoordinated phosphorus

    NASA Astrophysics Data System (ADS)

    Zhokhov, A. K.; Fomenko, P. V.; Aparkin, A. M.; Belousov, E. B.

    2015-01-01

    A method for determining the gas chromatographic retention indices of structural isomers of compounds of tetracoordinated phosphorus, based on the correlation between chemical shifts in 13C nuclear magnetic resonance (NMR) spectra and the retention indices of the structural isomers, and on the theory of intermolecular interactions, is proposed. The capabilities of the method are demonstrated for structural isomers of O-alkylmethylfluorophosphonates, which are typical representatives of compounds from the class of tetracoordinated phosphonates. The results from using the correlation approach are compared to experimental data.

  17. An experimental path to constraining the origin of Jupiter’s Trojan asteroids by identifying chemical fingerprints

    NASA Astrophysics Data System (ADS)

    Blacksberg, Jordana; Mahjoub, Ahmed; Poston, Michael; Brown, Mike; Eiler, John; Ehlmann, Bethany; Hand, Kevin; Carlson, Robert W.; Hodyss, Robert; Wong, Ian

    2015-11-01

    We present an experimental study aimed at exploring the hypothesis suggested by recent dynamical models – that the Jupiter Trojan asteroids originated in the outer solar system, were scattered by the same instability responsibility for the radical rearrangement of the giant planets, and were subsequently captured in their current location (e.g. Morbidelli et al., 2005, Nesvorny et al., 2013). We seek to identify spectroscopic, chemical and isotopic properties that can tie the Trojan populations to these evolutionary pathways, providing experimental support of dynamical models, and providing testable hypotheses that can feed into the design of experiments that might be performed on potential future missions to these and other primitive bodies.We present the results of experiments devised to explore the hypothesis that Kuiper Belt Objects (KBOs) represent the parent populations of the Trojan asteroids. Numerous thin ice films composed of select solar system volatiles (H2O, H2S, CH3OH, NH3) were grown in various mixtures to simulate compositional changes of icy bodies as a function of volatility and radial distance of formation from the Sun. Subsequent processing of these icy bodies was simulated using electron irradiation and heating. Visible reflectance spectra show significant reddening when H2S is present. Mid-infrared spectra confirm the formation of non-volatile sulfur-containing molecules in the products of H2S-containing ices. These experiments suggest that the presence of specific sulfur-bearing chemical species may play an important role in the colors of both the KBOs and Trojans today. Finally, we discuss the role of the silicate component expected on the surface of the Trojan asteroids (Emery et al., 2006), and the implications of a surface composed of silicates in intimate contact with the nonvolatile organic residues generated by ice irradiation.This work has been supported by the Keck Institute for Space Studies (KISS). The research described here was carried out at the Jet Propulsion Laboratory, Caltech, under a contract with the National Aeronautics and Space Administration (NASA) and at the Caltech Division of Geological and Planetary Sciences.

  18. Chemical composition and cytotoxicity evaluation of essential oil from leaves of Casearia sylvestris, its main compound ?-zingiberene and derivatives.

    PubMed

    Bou, Diego Dinis; Lago, João Henrique G; Figueiredo, Carlos R; Matsuo, Alisson L; Guadagnin, Rafael C; Soares, Marisi G; Sartorelli, Patricia

    2013-01-01

    Casearia sylvestris (Salicaceae), popularly known as "guaçatonga", is a plant widely used in folk medicine to treat various diseases, including cancer. The present work deals with the chemical composition as well as the cytotoxic evaluation of its essential oil, its main constituent and derivatives. Thus, the crude essential oil from leaves of C. sylvestris was obtained using a Clevenger type apparatus and analyzed by GC/MS. This analysis afforded the identification of 23 substances, 13 of which corresponded to 98.73% of the total oil composition, with sesquiterpene a-zingiberene accounting for 50% of the oil. The essential oil was evaluated for cytotoxic activity against several tumor cell lines, giving IC50 values ranging from 12 to 153 mg/mL. Pure a-zingiberene, isolated from essential oil, was also evaluated against the tumor cell lines showing activity for HeLa, U-87, Siha and HL60 cell lines, but with IC50 values higher than those determined for the crude essential oil. Aiming to evaluate the effect of the double bonds of a-zingiberene on the cytotoxic activity, partially hydrogenated a-zingiberene (PHZ) and fully hydrogenated a-zingiberene (THZ) derivatives were obtained. For the partially hydrogenated derivative only cytotoxic activity to the B16F10-Nex2 cell line (IC50 65 mg/mL) was detected, while totally hydrogenated derivative showed cytotoxic activity for almost all cell lines, with B16F10-Nex2 and MCF-7 as exceptions and with IC50 values ranging from 34 to 65 mg/mL. These results indicate that cytotoxic activity is related with the state of oxidation of compound. PMID:23966073

  19. D-fructose-6-phosphate aldolase in organic synthesis: cascade chemical-enzymatic preparation of sugar-related polyhydroxylated compounds.

    PubMed

    Concia, Alda Lisa; Lozano, Carles; Castillo, José A; Parella, Teodor; Joglar, Jesús; Clapés, Pere

    2009-01-01

    Novel aldol addition reactions of dihydroxyacetone (DHA) and hydroxyacetone (HA) to a variety of aldehydes catalyzed by D-fructose-6-phosphate aldolase (FSA) are presented. In a chemical-enzymatic cascade reaction approach, 1-deoxynojirimycin and 1-deoxymannojirimycin were synthesized starting from (R)- and (S)-3-(N-Cbz-amino)-2-hydroxypropanal, respectively. Furthermore, 1,4-dideoxy-1,4-imino-D-arabinitol and 1,4,5-trideoxy-1,4-imino-D-arabinitol were prepared from N-Cbz-glycinal. 1-Deoxy-D-xylulose was also synthesized by using HA as the donor and either 2-benzyloxyethanal or 2-hydroxyethanal as acceptors. In both cases the enzymatic aldol addition reaction was fully stereoselective, but with 2-hydroxyethanal 17 % of the epimeric product at C2, 1-deoxy-D-erythro-2-pentulose, was observed due to enolization/epimerization during the isolation steps. It was also observed that D-(-)-threose is a good acceptor substrate for FSA, opening new synthetic possibilities for the preparation of important novel complex carbohydrate-related compounds from aldoses. To illustrate this, 1-deoxy-D-ido-hept-2-ulose was obtained stereoselectively by the addition of HA to D-(-)-threose, catalyzed by FSA. It was found that the reaction performance depended strongly on the donor substrate, HA being the one that gave the best conversions to the aldol adduct. The examples presented in this work show the valuable synthetic potential of FSA for the construction of chiral complex polyhydroxylated sugar-type structures. PMID:19222084

  20. Preliminary use of compound-specific stable isotope (CSSI) technique to identify and apportion sediment origin in a small Austrian catchment

    NASA Astrophysics Data System (ADS)

    Mabit, Lionel; Gibbs, Max; Chen, Xu; Meusburger, Katrin; Toloza, Arsenio; Resch, Christian; Klik, Andreas; Eder, Alexander; Strauss, Peter; Alewell, Christine

    2015-04-01

    The overall impacts of climate change on agriculture are expected to be negative, threatening global food security. In the agricultural areas of the European Union, water erosion risk is expected to increase by about 80% by the year 2050. Reducing soil erosion and sedimentation-related environmental problems represent a key requirement for mitigating the impact of climate change. A new forensic stable isotope technique, using the compound specific stable isotope (CSSI) signatures of inherent soil organic biomarkers, can discriminate and apportion the source soil contribution from different land uses. Plant communities label the soil where they grow by exuding organic biomarkers. Although all plants produce the same biomarkers, the stable isotopic signature of those biomarkers is different for each plant species. For agri-environmental investigation, the CSSI technique is based on the measurement of carbon-13 (13-C) natural abundance signatures of specific organic compounds such as natural fatty acids (FAs) in the soil. By linking fingerprints of land use to the sediment in deposition zones, this approach has been shown to be a useful technique for determining the source of eroded soil and thereby identifying areas prone to soil degradation. The authors have tested this innovative stable isotopic approach in a small Austrian agricultural catchment located 60 km north of Vienna. A previous fallout radionuclide (i.e. 137-Cs) based investigation established a sedimentation rate of 4 mm/yr in the lowest part of the study site. To gain knowledge about the origin of these sediments, the CSSI technique was then tested using representative samples from the different land-uses of the catchment as source material. Values of 13-C signatures of specific FAs (i.e. C22:0 = Behenic Acid ; C24:0 = Lignoceric Acid) and the bulk 13-C of the sediment mixture and potential landscape sources were analyzed with the mixing models IsoSource and CSSIAR v1.00. Using both mixing models, preliminary results highlighted that about 50-55% of the sediment located in the deposition area originated from the main grassed waterway of the catchment.

  1. Organic Compounds in Carbonaceous Meteorites

    NASA Technical Reports Server (NTRS)

    Cooper, Grorge

    2001-01-01

    Carbonaceous meteorites are relatively enriched in soluble organic compounds. To date, these compounds provide the only record available to study a range of organic chemical processes in the early Solar System chemistry. The Murchison meteorite is the best-characterized carbonaceous meteorite with respect to organic chemistry. The study of its organic compounds has related principally to aqueous meteorite parent body chemistry and compounds of potential importance for the origin of life. Among the classes of organic compounds found in Murchison are amino acids, amides, carboxylic acids, hydroxy acids, sulfonic acids, phosphonic acids, purines and pyrimidines (Table 1). Compounds such as these were quite likely delivered to the early Earth in asteroids and comets. Until now, polyhydroxylated compounds (polyols), including sugars (polyhydroxy aldehydes or ketones), sugar alcohols, sugar acids, etc., had not been identified in Murchison. Ribose and deoxyribose, five-carbon sugars, are central to the role of contemporary nucleic acids, DNA and RNA. Glycerol, a three-carbon sugar alcohol, is a constituent of all known biological membranes. Due to the relative lability of sugars, some researchers have questioned the lifetime of sugars under the presumed conditions on the early Earth and postulated other (more stable) compounds as constituents of the first replicating molecules. The identification of potential sources and/or formation mechanisms of pre-biotic polyols would add to the understanding of what organic compounds were available, and for what length of time, on the ancient Earth.

  2. Reactive Transport Modeling of Chemical and Isotope Data to Identify Degradation Processes of Chlorinated Ethenes in a Diffusion-Dominated Media

    NASA Astrophysics Data System (ADS)

    Chambon, J. C.; Damgaard, I.; Jeannottat, S.; Hunkeler, D.; Broholm, M. M.; Binning, P. J.; Bjerg, P. L.

    2012-12-01

    Chlorinated ethenes are among the most widespread contaminants in the subsurface and a major threat to groundwater quality at numerous contaminated sites. Many of these contaminated sites are found in low-permeability media, such as clay tills, where contaminant transport is controlled by diffusion. Degradation and transport processes of chlorinated ethenes are not well understood in such geological settings, therefore risk assessment and remediation at these sites are particularly challenging. In this work, a combined approach of chemical and isotope analysis on core samples, and reactive transport modeling has been used to identify the degradation processes occurring at the core scale. The field data was from a site located at Vadsby, Denmark, where chlorinated solvents were spilled during the 1960-70's, resulting in contamination of the clay till and the underlying sandy layer (15 meters below surface). The clay till is heavily contaminated between 4 and 15 mbs, both with the mother compounds PCE/TCE and TCA and the daughter products (DCE, VC, ethene, DCA), indicating the occurrence of natural dechlorination of both PCE/TCE and TCA. Intact core samples of length 0.5m were collected from the source zone (between 6 and 12 mbs). Concentrations and stable isotope ratios of the mother compounds and their daughter products, as well as redox parameters, fatty acids and microbial data, were analyzed with discrete sub-sampling along the cores. More samples (each 5 mm) were collected around the observed higher permeability zones such as sand lenses, sand stringers and fractures, where a higher degradation activity was expected. This study made use of a reactive transport model to investigate the appropriateness of several conceptual models. The conceptual models considered the location of dechlorination and degradation pathways (biotic reductive dechlorination or abiotic ?-elimination with iron minerals) in three core profiles. The model includes diffusion in the matrix, sequential reductive dechlorination, abiotic degradation, isotope fractionation due to degradation and due to diffusion in the clay matrix, as heavier isotopes are expected to diffuse slower than lighter ones. The isotope data are shown to be crucial to distinguish between the tested conceptual models for transport and degradation, and made it possible to select a unique conceptual model for each core profile. This study reveals that biotic and abiotic degradation occurred concurrently in several zones inside the clay matrix, and that abiotic degradation of cis-DCE was the dominant attenuation process in the cores. Furthermore reductive dechlorination of cis-DCE to VC, and further to ethene, was documented in several zones in the low-permeability media. Previous studies have shown that degradation might be limited to high permeability zones in clay tills, thus limiting the applicability of remediation strategies based on enhanced biodegradation. Therefore the occurrence of degradation inside the clay matrix is an important finding, that is further supported by microbial and chemical data. Improved understanding of degradation processes in clay tills is useful for improving the reliability of risk assessment and the design of remediation schemes for chlorinated solvents.

  3. The TSCA Interagency Testing Committee (ITC) proposed strategy for identifying and coordinating U.S. government data needs for endocrine-disrupting chemicals

    SciTech Connect

    Walker, J.D.

    1995-12-31

    The ITC`s Endocrine-Disrupting Chemicals Subcommittee will implement a proposed strategy for identifying and coordinating the US government ecological and health effects data needs for endocrine-disrupting chemicals, These include chemicals with potential to cause reproductive, developmental, immunological, neurologic or other biological effects by adversely affecting endocrine tissues, hormones or receptors in fish, wildlife or humans. To meet these needs, the Subcommittee will consider three options. First, the information collecting authority of the Toxic Substances Control Act (TSCA) will be considered as a cost-effective mechanism to rapidly (within 60 days) obtain unpublished health and ecological effects studies related to reproductive effects and endocrine-disrupting activity. Second, the chemical testing authority of TSCA will be considered as a method to request that the manufacturers of endocrine-disrupting chemicals conduct tests that are amenable to standardization. Third, consideration will be given to coordinating standardized testing with testing related to research and to using the results of this research to develop standardized methods for assessing the effects of endocrine-disrupting chemicals. The Subcommittee will focus on 16 alkylphenol and alkylphenol ethoxylates with 1989 production or importation volumes greater than 1 million pounds that were identified using the Substructure based Computerized Chemical Selection Expert System (SuCCSES). The ITC`s proposed strategy will be discussed.

  4. Minocycline and doxycycline, but not other tetracycline-derived compounds, protect liver cells from chemical hypoxia and ischemia/reperfusion injury by inhibition of the mitochondrial calcium uniporter

    SciTech Connect

    Schwartz, Justin; Holmuhamedov, Ekhson; Zhang, Xun; Lovelace, Gregory L.; Smith, Charles D.; Lemasters, John J.

    2013-11-15

    Minocycline, a tetracycline-derived compound, mitigates damage caused by ischemia/reperfusion (I/R) injury. Here, 19 tetracycline-derived compounds were screened in comparison to minocycline for their ability to protect hepatocytes against damage from chemical hypoxia and I/R injury. Cultured rat hepatocytes were incubated with 50 ?M of each tetracycline-derived compound 20 min prior to exposure to 500 ?M iodoacetic acid plus 1 mM KCN (chemical hypoxia). In other experiments, hepatocytes were incubated in anoxic Krebs–Ringer–HEPES buffer at pH 6.2 for 4 h prior to reoxygenation at pH 7.4 (simulated I/R). Tetracycline-derived compounds were added 20 min prior to reperfusion. Ca{sup 2+} uptake was measured in isolated rat liver mitochondria incubated with Fluo-5N. Cell killing after 120 min of chemical hypoxia measured by propidium iodide (PI) fluorometry was 87%, which decreased to 28% and 42% with minocycline and doxycycline, respectively. After I/R, cell killing at 120 min decreased from 79% with vehicle to 43% and 49% with minocycline and doxycycline. No other tested compound decreased killing. Minocycline and doxycycline also inhibited mitochondrial Ca{sup 2+} uptake and suppressed the Ca{sup 2+}-induced mitochondrial permeability transition (MPT), the penultimate cause of cell death in reperfusion injury. Ru360, a specific inhibitor of the mitochondrial calcium uniporter (MCU), also decreased cell killing after hypoxia and I/R and blocked mitochondrial Ca{sup 2+} uptake and the MPT. Other proposed mechanisms, including mitochondrial depolarization and matrix metalloprotease inhibition, could not account for cytoprotection. Taken together, these results indicate that minocycline and doxycycline are cytoprotective by way of inhibition of MCU. - Highlights: • Minocycline and doxycycline are the only cytoprotective tetracyclines of those tested • Cytoprotective tetracyclines inhibit the MPT and mitochondrial calcium and iron uptake. • Cytoprotective tetracyclines protect by inhibiting the MCU.

  5. A SAW-Based Chemical Sensor for Detecting Sulfur-Containing Organophosphorus Compounds Using a Two-Step Self-Assembly and Molecular Imprinting Technology

    PubMed Central

    Pan, Yong; Yang, Liu; Mu, Ning; Shao, Shengyu; Wang, Wen; Xie, Xiao; He, Shitang

    2014-01-01

    This paper presents a new effective approach for the sensitive film deposition of surface acoustic wave (SAW) chemical sensors for detecting organophosphorus compounds such as O-ethyl-S-2-diisopropylaminoethyl methylphosphonothiolate (VX) containing sulfur at extremely low concentrations. To improve the adsorptive efficiency, a two-step technology is proposed for the sensitive film preparation on the SAW delay line utilizing gold electrodes. First, mono[6-deoxy-6-[(mercaptodecamethylene)thio

  6. A SAW-based chemical sensor for detecting sulfur-containing organophosphorus compounds using a two-step self-assembly and molecular imprinting technology.

    PubMed

    Pan, Yong; Yang, Liu; Mu, Ning; Shao, Shengyu; Wang, Wen; Xie, Xiao; He, Shitang

    2014-01-01

    This paper presents a new effective approach for the sensitive film deposition of surface acoustic wave (SAW) chemical sensors for detecting organophosphorus compounds such as O-ethyl-S-2-diisopropylaminoethyl methylphosphonothiolate (VX) containing sulfur at extremely low concentrations. To improve the adsorptive efficiency, a two-step technology is proposed for the sensitive film preparation on the SAW delay line utilizing gold electrodes. First, mono[6-deoxy-6-[(mercaptodecamethylene)thio

  7. Volume 203, number 4 CHEMICAL PHYSICS LETTERS 26 February 1993 Lanthanide-and actinide-based fullerite compounds

    E-print Network

    that the A3C60 structure, which is isomorphic to K3C60, is the most stable phase for all rare earth compounds based superconductors. Inorganic compounds and organometallic mole- cules of lanthanide earths are known in organoac- tinides, where the bonds between the actinide earth elements and the organic moieties

  8. Chemical Preparation of the Binary Compounds in the CalciaAlumina System by Self-Propagating Combustion Synthesis

    E-print Network

    Tas, A. Cuneyt

    in a dry-air atmosphere. I. Introduction THE binary compounds of the calcia­alumina (CaO­Al2O3) system in casting, trowelling, and gunning applications. The pure, alkali-free binary compounds of the CaO­Al2O3-state reactive firing in kilns) has always been trouble- some, and the final product of conventional syntheses

  9. CARBON-13 NUCLEAR MAGNETIC RESONANCE. 13C CHEMICAL SHIFTS AND 13C-199HG COUPLING CONSTANTS FOR SOME ORGANOMERCURY COMPOUNDS

    EPA Science Inventory

    The (13)C shieldings and (13)C-(199)Hg coupling constants of fourteen phenyl- and seven alkyl- and alkenyl-mercury compounds have been obtained. Substituent effects on the (13)C shieldings are similar to those in nonmercurated phenyl compounds, with a similar relationship between...

  10. Replication-Competent Influenza Virus and Respiratory Syncytial Virus Luciferase Reporter Strains Engineered for Co-Infections Identify Antiviral Compounds in Combination Screens.

    PubMed

    Yan, Dan; Weisshaar, Marco; Lamb, Kristen; Chung, Hokyung K; Lin, Michael Z; Plemper, Richard K

    2015-09-15

    Myxoviruses such as influenza A virus (IAV) and respiratory syncytial virus (RSV) are major human pathogens, mandating the development of novel therapeutics. To establish a high-throughput screening protocol for the simultaneous identification of pathogen- and host-targeted hit candidates against either pathogen or both, we have attempted co-infection of cells with IAV and RSV. However, viral replication kinetics were incompatible, RSV signal window was low, and an IAV-driven minireplicon reporter assay used in initial screens narrowed the host cell range and restricted the assay to single-cycle infections. To overcome these limitations, we developed an RSV strain carrying firefly luciferase fused to an innovative universal small-molecule assisted shut-off domain, which boosted assay signal window, and a hyperactive fusion protein that synchronized IAV and RSV reporter expression kinetics and suppressed the identification of RSV entry inhibitors sensitive to a recently reported RSV pan-resistance mechanism. Combined with a replication-competent recombinant IAV strain harboring nanoluciferase, the assay performed well on a human respiratory cell line and supports multicycle infections. Miniaturized to 384-well format, the protocol was validated through screening of a set of the National Institutes of Health Clinical Collection (NCC) in quadruplicate. These test screens demonstrated favorable assay parameters and reproducibility. Application to a LOPAC library of bioactive compounds in a proof-of-concept campaign detected licensed antimyxovirus therapeutics, ribavirin and the neuraminidase inhibitor zanamivir, and identified two unexpected RSV-specific hit candidates, Fenretinide and the opioid receptor antagonist BNTX-7. Hits were evaluated in direct and orthogonal dose-response counterscreens using a standard recRSV reporter strain expressing Renilla luciferase. PMID:26307636

  11. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2001-01-01

    Seawater and natural brines accounted for about 63% of US magnesium compounds production during 2000. Premier Services in Florida, Dow Chemical in Michigan, Martin Marietta Magnesia Specialties, and Rohm & Haas recovered dead-burned and caustic-calcined magnesias from seawater. And Premier Services' recoveries, in Nevada, were from magnasite.

  12. 40 CFR 721.9597 - Salt of a substituted sulfonated aryl azo compound (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Salt of a substituted sulfonated aryl azo compound...Specific Chemical Substances § 721.9597 Salt of a substituted sulfonated aryl azo compound...chemical substance identified generically as salt of a substituted sulfonated aryl...

  13. 40 CFR 721.9597 - Salt of a substituted sulfonated aryl azo compound (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Salt of a substituted sulfonated aryl azo compound...Specific Chemical Substances § 721.9597 Salt of a substituted sulfonated aryl azo compound...chemical substance identified generically as salt of a substituted sulfonated aryl...

  14. 40 CFR 721.9597 - Salt of a substituted sulfonated aryl azo compound (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Salt of a substituted sulfonated aryl azo compound...Specific Chemical Substances § 721.9597 Salt of a substituted sulfonated aryl azo compound...chemical substance identified generically as salt of a substituted sulfonated aryl...

  15. 40 CFR 721.3320 - Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine (1:1).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine...Specific Chemical Substances § 721.3320 Ethanol, 2-amino-, com-pound with N -hydroxy-N...The chemical substance identified as ethanol, 2-amino-, compound with N...

  16. 40 CFR 721.3320 - Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine (1:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine...Specific Chemical Substances § 721.3320 Ethanol, 2-amino-, com-pound with N -hydroxy-N...The chemical substance identified as ethanol, 2-amino-, compound with N...

  17. 40 CFR 721.3320 - Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine (1:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine...Specific Chemical Substances § 721.3320 Ethanol, 2-amino-, com-pound with N -hydroxy-N...The chemical substance identified as ethanol, 2-amino-, compound with N...

  18. 40 CFR 721.3320 - Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine (1:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine...Specific Chemical Substances § 721.3320 Ethanol, 2-amino-, com-pound with N -hydroxy-N...The chemical substance identified as ethanol, 2-amino-, compound with N...

  19. 40 CFR 721.3320 - Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine (1:1).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Ethanol, 2-amino-, com-pound with N-hydroxy-N-nitro-soben-zena-mine...Specific Chemical Substances § 721.3320 Ethanol, 2-amino-, com-pound with N -hydroxy-N...The chemical substance identified as ethanol, 2-amino-, compound with N...

  20. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2002-01-01

    Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  1. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2010-01-01

    Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

  2. 40 CFR 721.9970 - o-Xylene compound (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false o-Xylene compound (generic name). 721.9970 Section...Substances § 721.9970 o-Xylene compound (generic name). (a) Chemical...identified generically as an o -xylene compound (PMN P-95-1030) is subject...

  3. Characteristic Chemical Components and Aroma-active Compounds of the Essential Oils from Ranunculus nipponicus var. submersus Used in Japanese Traditional Food.

    PubMed

    Nakaya, Satoshi; Usami, Atsushi; Yorimoto, Tomohito; Miyazawa, Mitsuo

    2015-01-01

    Ranunculus nipponicus var. submersus is an aquatic macrophyte; it is known as a wild edible plant in Japan for a long time. In this study, the essential oils from the fresh and dried aerial parts of R. nipponicus var. submersus were extracted by hydrodistillation and analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). Moreover, important aroma-active compounds were also detected in the oil using GC-olfactometry (GC-O) and aroma extract dilution analysis (AEDA). Thus, 98 compounds (accounting for 93.86%) of the oil were identified. The major compounds in fresh plant oil were phytol (41.94%), heptadecane (5.92%), and geranyl propionate (5.76%), while those of. Dried plant oil were ?-ionone (23.54%), 2-hexenal (8.75%), and dihydrobovolide (4.81%). The fresh and dried oils had the green-floral and citrus-floral odor, respectively. The GC-O and AEDA results show that phenylacetaldehyde (green, floral odor, FD-factor = 8) and ?-ionone (violet-floral odor, FD-factor = 8) were the most characteristic odor compounds of the fresh oils. ?-Cyclocitral (citrus odor, FD-factor = 64) and ?-ionone (violet-floral odor, FD-factor = 64) were the most characteristic odor compounds of the dried oil. These compounds are thought to contribute to the flavor of R. nipponicus var. submersus. PMID:25891110

  4. Effect of chemical freeze out on identified particle spectra at 200AGeV Au-Au Collisions at RHIC using SPheRIO

    E-print Network

    Wei-Liang Qian; Rone Andrade; Frederique Grassi; Otavio Socolowski Jr.; Takeshi Kodama; Yogiro Hama

    2007-03-23

    We investigate the effect of chemical freeze-out on identified particle spectra at 200AGeV Au-Au Collisions at RHIC, by utilizing a full three-dimensional hydrodynamical calculation. The hydrodynamical code SPheRIO we employed is based on the smoothed particle hydrodynamic algorithm. In order to describe the spectra of strange hadrons, the code has been further improved by explicitly incorporating the strangeness conservation and a chemical freeze-out mechanism. In our model, strange hadrons such as Lambda, Xi, Omega and phi undergo the chemical freeze-out immediately after the hadronization, and their multiplicities are fixed thereafter. At a lower temperature the thermal freeze-out takes place for all the particles. It is shown that the present model provides a reasonably good description for the spectra of identified particles, in particular, considerable improvement is observed for those of strange hadrons.

  5. Electron attachment identifies carcinogens

    SciTech Connect

    Not Available

    1984-09-17

    The rate of electron attachment to a compound dissolved in a nonpolar solvent identifies carcinogens and noncarcinogens with sensitivity and specificity comparable to the Ames Salmonella bioassay, according to George Bakale, a professor in the radiology department, Case Western Reserve University, Cleveland. Bakale described a pulse conductivity technique for measuring the rate of electron attachment to compounds and the results of studies of known carcinogens and noncarcinogens dissolved in isooctane or cyclohexane. A positive response occurs when that rate is equal to the diffusion-controlled rate of electron attachment, indicating that the chemical can interact efficiently with electron-rich molecules such as deoxyribonucleic acid (DNA), the molecule generally considered to be the target for the initiation of chemical carcinogenesis. Using that criterion, the technique correctly identifies 55 of 65 known carcinogens and 48 of 55 noncarcinogens. That translates to a sensitivity (correct identification of carcinogens) of 85%. The pulse conductivity technique is a relative of pulse radiolysis. The researchers irradiate the solution under study with a short pulse of 1-MeV electrons, which creates a homogeneous distribution of electrons and ions. The solution is between parallel plates across which an electric potential is applied. The electrons in solution move in the electric field setting up a current. The decay of the current follows pseudo-first-order kinetics allowing a simple calculation of the rate of electron attachment from the half-life of the electrons in solution.

  6. Adverse Outcome Pathway for Embryonic Vascular Disruption and Alternative Methods to Identify Chemical Vascular Disruptors During Development

    EPA Science Inventory

    Chemically induced vascular toxicity during embryonic development can result in a wide range of adverse prenatal outcomes. We used information from genetic mouse models linked to phenotypic outcomes and a vascular toxicity knowledge base to construct an embryonic vascular disrupt...

  7. Crystallographic properties of fertilizer compounds

    SciTech Connect

    Frazier, A.W.; Dillard, E.F.; Thrasher, R.D.; Waerstad, K.R.; Hunter, S.R.; Kohler, J.J.; Scheib, R.M.

    1991-02-01

    This bulletin is a compilation of crystallographic data collected at NFERC on 450 fertilizer-related compounds. In TVA's fertilizer R and D program, petrographic examination, XRD, and infrared spectroscopy are combined with conventional chemical analysis methods in identifying the individual compounds that occur in fertilizer materials. This handbook brings together the results of these characterization studies and supplemental crystallographic data from the literature. It is in one-compound-per-page, loose-leaf format, ordered alphabetically by IUPAC name. Indexes provided include IUPAC name, formula, group, alternate formula, synonyms, x-ray data, optical data. Tables are given for solids, compounds in commercial MAP and DAP, and matrix materials in phosphate rock.

  8. Screen of FDA-approved drug library identifies maprotiline, an antibiofilm and antivirulence compound with QseC sensor-kinase dependent activity in Francisella novicida.

    PubMed

    Dean, Scott N; van Hoek, Monique L

    2015-01-01

    Development of new therapeutics against Select Agents such as Francisella is critical preparation in the event of bioterrorism. Testing FDA-approved drugs for this purpose may yield new activities unrelated to their intended purpose and may hasten the discovery of new therapeutics. A library of 420 FDA-approved drugs was screened for antibiofilm activity against a model organism for human tularemia, Francisella (F.) novicida, excluding drugs that significantly inhibited growth. The initial screen was based on the 2-component system (TCS) dependent biofilm effect, thus, the QseC dependence of maprotiline anti-biofilm action was demonstrated. By comparing their FDA-approved uses, chemical structures, and other properties of active drugs, toremifene and polycyclic antidepressants maprotiline and chlorpromazine were identified as being highly active against F. novicida biofilm formation. Further down-selection excluded toremifene for its membrane active activity and chlorpromazine for its high antimicrobial activity. The mode of action of maprotiline against F. novicida was sought. It was demonstrated that maprotiline was able to significantly down-regulate the expression of the virulence factor IglC, encoded on the Francisella Pathogenicity Island (FPI), suggesting that maprotiline is exerting an effect on bacterial virulence. Further studies showed that maprotiline significantly rescued F. novicida infected wax worm larvae. In vivo studies demonstrated that maprotiline treatment could prolong time to disease onset and survival in F. novicida infected mice. These results suggest that an FDA-approved drug such as maprotiline has the potential to combat Francisella infection as an antivirulence agent, and may have utility in combination with antibiotics. PMID:26155740

  9. Identify five kinds of simple super-secondary structures with quadratic discriminant algorithm based on the chemical shifts.

    PubMed

    Kou, Gaoshan; Feng, Yonge

    2015-09-01

    The biological function of protein is largely determined by its spatial structure. The research on the relationship between structure and function is the basis of protein structure prediction. However, the prediction of super secondary structure is an important step in the prediction of protein spatial structure. Many algorithms have been proposed for the prediction of protein super secondary structure. However, the parameters used by these methods were primarily based on amino acid sequences. In this paper, we proposed a novel model for predicting five kinds of protein super secondary structures based on the chemical shifts (CSs). Firstly, we analyzed the statistical distribution of chemical shifts of six nuclei in five kinds of protein super secondary structures by using the analysis of variance (ANOVA). Secondly, we used chemical shifts of six nuclei as features, and combined with quadratic discriminant analysis (QDA) to predict five kinds of protein super secondary structures. Finally, we achieved the averaged sensitivity, specificity and the overall accuracy of 81.8%, 95.19%, 82.91%, respectively in seven-fold cross-validation. Moreover, we have performed the prediction by combining the five different chemical shifts as features, the maximum overall accuracy up to 89.87% by using the C,C?,C?,N,H? of H? chemical shifts, which are clearly superior to that of the quadratic discriminant analysis (QDA) algorithm by using 20 amino acid compositions (AAC) as feature in the seven-fold cross-validation. These results demonstrated that chemical shifts (CSs) are indeed an outstanding parameter for the prediction of five kinds of super secondary structures. In addition, we compared the prediction of the quadratic discriminant analysis (QDA) with that of support vector machine (SVM) by using the same six CSs as features. The result suggested that the quadratic discriminant analysis method by using chemical shifts as features is a good predictor for protein super secondary structures. PMID:26087283

  10. Chemical speciation and source apportionment of Non-Methane Volatile Organic Compounds (NMVOCs) in a Middle Eastern country

    NASA Astrophysics Data System (ADS)

    Salameh, Therese; Sauvage, Stéphane; Afif, Charbel; Borbon, Agnès; Locoge, Nadine

    2014-05-01

    NMVOCs, emitted from various sources, are of particular interest since they contribute to the formation of tropospheric ozone, PAN and secondary organic aerosols resulting in negative impacts on human health, climate and on the environment. To identify abatement measures, a profound knowledge of emission sources and their composition is a prerequisite. Air pollution in the Middle East region remains difficult to assess and understand because of a lack of ground-based measurements and the limited information on NMVOC chemical speciation and source apportionment. Based on a large database of NMVOC observations obtained in Beirut, the capital of Lebanon (a developing country in the Middle East region, located in Western Asia on the eastern shore of the Mediterranean Sea), the overall objective of this work is to apportion the sources of NMVOCs encountered in Lebanon. First, source profiles were determined with field measurements close to the main potential emitters namely the road transport, gasoline vapour, power generation and solvent uses. The results obtained are compared to other studies held in other regions and are used to assess the emission inventory developed for Lebanon. Secondly, two intensive field campaigns were held in a receptor site in Beirut during summer 2011 and winter 2012 in order to obtain a large time resolved dataset. The PMF analysis of this dataset was applied to apportion anthropogenic sources in this area. In both seasons, combustion (road transport and power generation) and gasoline evaporation, especially in winter, were the main sources contributing to the NMVOCs in Beirut. The results will support model implementation especially by completing the emission inventory established for the year 2010 by Waked et al. 2012 according to the EEA/EMEP guidelines because of the lack of Lebanon-specific emission factor.

  11. Changes in physico-chemical and volatile aroma compound composition of Gewürztraminer wine as a result of late and ice harvest.

    PubMed

    Luki?, Igor; Radeka, Sanja; Grozaj, Nikola; Staver, Mario; Peršuri?, ?ordano

    2016-04-01

    To investigate the changes in physico-chemical and aroma composition after late and ice harvest, Gewürztraminer wines were subjected to standard, enzymatic and GC/MS analysis. Late harvest (LHGW) and ice wines (IHGW) contained more sugars, extract and volatile acidity than standard wines (SGW). IHGW had elevated glycerol and gluconic acid amounts. LHGW was richer in monoterpenol oxides, ?-damascenone, 1-octen-3-ol, acetates, ethyl cinnamate and 4-vinylguaiacol than SGW. IHGW contained even higher amounts, with increased citronellol, acetaldehyde, ethyl acetate, dicarboxylic acids esters, benzenoids, furans and acetals, and reduced fermentation aroma compounds. Based on odour activity values, the strongest odorants in SGW were fruity esters. In LHGW the impact of esters increased, while in IHGW cis-rose oxide, ?-damascenone and 1,1-diethoxyethane emerged as the most potent. Fruity and sweet were the dominant aroma compound series in SGW and LHGW, but in IHGW declined, while terpenic, floral, chemical, pungent and ripe fruit aroma compound series increased. PMID:26593588

  12. Influence of cooking on the levels of bioactive compounds in Purple Majesty potato observed via chemical and spectroscopic means.

    PubMed

    Lemos, M Adília; Aliyu, Maryam M; Hungerford, Graham

    2015-04-15

    Tubers rich in phytochemicals can exhibit a potential health benefit. This work aims at studying the relative effect of different domestic cooking techniques by monitoring the level of total phenolic compounds (TP), total anthocyanins (TA) and anti-oxidant activity (AOA) on a variety of pigmented potatoes. Raw purple potatoes are a good source of anthocyanins (219 mg/kg FW) and the level of these compounds increased using different cooking techniques, with the exception of baking. However, the levels of phenolic compounds (originally 209 mg GAE/100 g FW) decreased in the cooked potatoes. Although potatoes contain different antioxidants in this work the antioxidant activity seems to be related to the levels of phenolic compounds present in the pigmented potato. The fact that some of the compounds present fluoresce enabled both steady state and time-resolved fluorescence techniques to be assessed as a non destructive means of monitoring. This elucidated the presence of different components (via spectral deconvolution and time-resolved emission spectra). Their relative contribution to the fluorescence emission was found to be affected by the different cooking process, with a longer wavelength emission appearing to relate to reflect the presence of anthocyanins. PMID:25466046

  13. CSI 3.0: a web server for identifying secondary and super-secondary structure in proteins using NMR chemical shifts.

    PubMed

    Hafsa, Noor E; Arndt, David; Wishart, David S

    2015-07-01

    The Chemical Shift Index or CSI 3.0 (http://csi3.wishartlab.com) is a web server designed to accurately identify the location of secondary and super-secondary structures in protein chains using only nuclear magnetic resonance (NMR) backbone chemical shifts and their corresponding protein sequence data. Unlike earlier versions of CSI, which only identified three types of secondary structure (helix, ?-strand and coil), CSI 3.0 now identifies total of 11 types of secondary and super-secondary structures, including helices, ?-strands, coil regions, five common ?-turns (type I, II, I', II' and VIII), ? hairpins as well as interior and edge ?-strands. CSI 3.0 accepts experimental NMR chemical shift data in multiple formats (NMR Star 2.1, NMR Star 3.1 and SHIFTY) and generates colorful CSI plots (bar graphs) and secondary/super-secondary structure assignments. The output can be readily used as constraints for structure determination and refinement or the images may be used for presentations and publications. CSI 3.0 uses a pipeline of several well-tested, previously published programs to identify the secondary and super-secondary structures in protein chains. Comparisons with secondary and super-secondary structure assignments made via standard coordinate analysis programs such as DSSP, STRIDE and VADAR on high-resolution protein structures solved by X-ray and NMR show >90% agreement between those made with CSI 3.0. PMID:25979265

  14. CSI 3.0: a web server for identifying secondary and super-secondary structure in proteins using NMR chemical shifts

    PubMed Central

    Hafsa, Noor E.; Arndt, David; Wishart, David S.

    2015-01-01

    The Chemical Shift Index or CSI 3.0 (http://csi3.wishartlab.com) is a web server designed to accurately identify the location of secondary and super-secondary structures in protein chains using only nuclear magnetic resonance (NMR) backbone chemical shifts and their corresponding protein sequence data. Unlike earlier versions of CSI, which only identified three types of secondary structure (helix, ?-strand and coil), CSI 3.0 now identifies total of 11 types of secondary and super-secondary structures, including helices, ?-strands, coil regions, five common ?-turns (type I, II, I?, II? and VIII), ? hairpins as well as interior and edge ?-strands. CSI 3.0 accepts experimental NMR chemical shift data in multiple formats (NMR Star 2.1, NMR Star 3.1 and SHIFTY) and generates colorful CSI plots (bar graphs) and secondary/super-secondary structure assignments. The output can be readily used as constraints for structure determination and refinement or the images may be used for presentations and publications. CSI 3.0 uses a pipeline of several well-tested, previously published programs to identify the secondary and super-secondary structures in protein chains. Comparisons with secondary and super-secondary structure assignments made via standard coordinate analysis programs such as DSSP, STRIDE and VADAR on high-resolution protein structures solved by X-ray and NMR show >90% agreement between those made with CSI 3.0. PMID:25979265

  15. [Chemical characterization and quantification of fructooligosaccharides, phenolic compounds and antiradical activity of Andean roots and tubers grown in Northwest of Argentina].

    PubMed

    Jiménez, María Eugenia; Sammán, Norma

    2014-06-01

    There is great interest in consuming foods that can provide the nutrients for a good nutrition and other health beneficial compounds. The aim of this work was to determine the chemical composition of native foods of the Andean region and to quantify some functional com-ponents. Proximal composition, vitamin C, total phenolic compounds, antiradical activity (DPPH) in peel and pulp, dietary fiber soluble and insoluble, fructooligosaccharides (FOS), total and resistant starch (in tubers and raw roots, boiled and boiled and stored) of 6 varieties of Oca (Oxalis tuberosa), 4 clones of manioc (Manihot esculenta Crantz) and yacon (Smallanthus sonchifolius were determined. The results showed greater amount of bioactive compounds and antiradical activity in the skin of these products. The highest content was found in the oca peel. In all cases, the content of insoluble fiber was greater than the soluble. The manioc had higher total starch than Andean roots and tubers. The boiling process decreased the resistant starch content of ocas and maniocs, but when these are stored for 48 h at 5 ° C, the resistant starch content increased. The FOS content of the ocas was similar for all varieties (7%). The main component of yacon carbohydrates were FOS (8.89%). The maniocs did not contain FOS. It can be concluded that the roots and tubers studied, in addition to provide nutrients, contain functional compounds that confer additional helpful value for preventing no communicable diseases. PMID:25799690

  16. Occurrence, production, and export of lipophilic compounds by hydrocarbonoclastic marine bacteria and their potential use to produce bulk chemicals from hydrocarbons.

    PubMed

    Manilla-Pérez, Efraín; Lange, Alvin Brian; Hetzler, Stephan; Steinbüchel, Alexander

    2010-05-01

    Petroleum (or crude oil) is a complex mixture of hydrocarbons. Annually, millions of tons of crude petroleum oil enter the marine environment from either natural or anthropogenic sources. Hydrocarbon-degrading bacteria (HDB) are able to assimilate and metabolize hydrocarbons present in petroleum. Crude oil pollution constitutes a temporary condition of carbon excess coupled to a limited availability of nitrogen that prompts marine oil-degrading bacteria to accumulate storage compounds. Storage lipid compounds such as polyhydroxyalkanoates (PHAs), triacylglycerols (TAGs), or wax esters (WEs) constitute the main accumulated lipophilic substances by bacteria under such unbalanced growth conditions. The importance of these compounds as end-products or precursors to produce interesting biotechnologically relevant chemicals has already been recognized. In this review, we analyze the occurrence and accumulation of lipid storage in marine hydrocarbonoclastic bacteria. We further discuss briefly the production and export of lipophilic compounds by bacteria belonging to the Alcanivorax genus, which became a model strain of an unusual group of obligate hydrocarbonoclastic bacteria (OHCB) and discuss the possibility to produce neutral lipids using A. borkumensis SK2. PMID:20354694

  17. Chemical and Nutritional Ecology of Lucilia sericata (Meigen) (Diptera: Calliphoridae) as Related to Volatile Organic Compounds and Associated Essential Amino Acids 

    E-print Network

    Liu, Wenqi

    2014-08-07

    pneumoniae were most sensitive to the antibacterial effects of ES and P. mirabilis and Staphylococcus epidermidis were the most resistant [54]. Other compounds that are potentially antimicrobial have been isolated and identified from L. sericata ES... Methicillin-resistant Staphylococcus aureus GLC Head-space gas-liquid chromatography DEET N, N-diethyl-m-toluamide DNase Deoxyribonuclease AG Age group NG Non-gravid female...

  18. Decision-Support in the Wild: A Qualitative Study on How First Responders Use Technology for Rapidly Identifying Toxic Chemicals

    E-print Network

    Bhavnani, Suresh K.

    Health, University of Michigan; 5 Dr. Hazmat Inc., Denver, CO Abstract Although many decision emergency response. For example, a hazmat technician stated that he played three roles during an incident including scene response, chemical assessment, and hazmat training, out of a total of 11 different roles

  19. Chemicals identified in feral and food animals: a data base. First annual report, October 1981. Volume I. Records 1-532

    SciTech Connect

    Cone, M.V.; Faust, R.A.; Baldauf, M.F.

    1981-12-01

    This data file is a companion to Chemicals Identified in Human Biological Media, A Data Base, and follows basically the same format. The data base on human burden is in its third year of publication. This is the first annual report for the feral and food animal file. Data were obtained primarily from the open literature through manual searches (retrospective to 1979) of the journals listed in Appendix A. The data base now contains information on 60 different substances. Chemicals are listed by Chemical Abstracts Service (CAS) registry numbers and preferred names in Appendix B. For the user's convenience, cross-referenced chemical lists of CAS preferred and common names are provided in Appendix C. The animals, tissues, and body fluids found to be contaminated by these chemicals are listed in Appendix D. The data base is published annually in tabular format with indices and chemical listings that allow specific searching. A limited number of custom computer searches of the data base are available in special cases when the published format does not allow for retrieval of needed information.

  20. USE OF THE FUNGICIDE CARBENDAZIM AS A MODEL COMPOUND TO DETERMINE THE IMPACT OF ACUTE CHEMICAL EXPOSURE DURING OOCYTE MATURATION AND FERTILIZATION ON PREGNANCY OUTCOME IN THE HAMSTER

    EPA Science Inventory

    Here we use a hamster animal model to identify early pregnancy loss due to an acute chemical exposure to the female during the perifertilization interval. The fungicide carbendazim (methyl 1H-benzimidazole-2-carbamate), a microtubule poison with antimitotic activity, was selected...

  1. Identifying military impacts on archaeology deposits based on differences in soil organic carbon and chemical elements at soil horizon interfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Historic Preservation Act requires land-managing agencies to identify and account for their impacts on archaeological resources. Regulatory agencies that oversee compliance with historic preservation legislation frequently assume military training adversely affects archaeological resou...

  2. Use of high-resolution mass spectrometry to identify precursors and biodegradation products of perfluorinated and polyfluorinated compounds in end-user products.

    PubMed

    Yamamoto, Atsushi; Hisatomi, Hirotaka; Ando, Tomoshige; Takemine, Shusuke; Terao, Tomoko; Tojo, Toshiki; Yagi, Masahiro; Ono, Daisuke; Kawasaki, Hideya; Arakawa, Ryuichi

    2014-07-01

    Structural identification of perfluoroalkyl and polyfluoroalkyl substances found in end-user products and their biodegradation products was performed using ultra-high resolution mass spectrometry. Little attention has so far been paid to the environmental burden of perfluorooctane sulfonate and perfluorooctanoic acid from compounds with a molar mass of ~2,000. Analysis of end-user waterproofing and stain repellent products revealed the presence of numerous ions with molar masses ranging from 1,000 to 2,000 and complex mass spectra. Ultra-high resolution mass spectrometry determined the accurate mass of the observed ions, allowing the cleavage position and fragment structure to be determined. The precursor structures were determined based on reconstitution of the retrieved fragments. Products of fluorochemical manufacturers before voluntary regulation comprised compounds with plural perfluorooctyl chains. In the current product lines, compounds comprising perfluorobutyl chains were detected. Biodegradation tests using activated sludge revealed that biodegradation products consistent with those reported previously were generated even from complex end-user products. For example, the biodegradation test revealed the formation of N-ethyl perfluorooctane sulfonamido acetic acid and various fluorotelomer acids in the samples. The results of the present study suggest that the environmental burden of these compounds should be reevaluated. PMID:24828983

  3. A Novel Way To Identify Precursors That Degrade To Perfluorinated Compounds In Activated Sludge Using Ion-Trap Time-Of-Flight Mass Spectrometry

    EPA Science Inventory

    An increasing number of studies have been conducted to investigate the environmental distribution of perfluorinated alkyl compounds (PFCs), many of which are known to be toxic in laboratory animals. Despite growing public concerns, fate and transport of PFCs are little known. M...

  4. A Novel Way To Identify Precursors That Degrade To Perfluourinated Compounds In Activated Sludge Using Ion-Trap Time-Of-Flight Mass Spectrometer

    EPA Science Inventory

    An increasing number of studies have been conducted to investigate the environmental distribution of perfluorinated alkyl compounds (PFCs), many of which are known to be toxic in laboratory animals. Despite growing public concerns, the fate and transport of PFCs are little under...

  5. Selected values of chemical thermodynamic properties: compounds of uranium, protactinium, thorium, actinium, and the alkali metals. Final report

    SciTech Connect

    Wagman, D.D.; Evans, W.H.; Parker, V.B.; Schumm, R.H.; Nuttall, R.L.

    1981-05-01

    This publication contains tables of recommended values for the standard enthalpies (heats) of formation, Gibbs (free) energies of formation, entropies, enthalpy contents and heat capacities at 298.15 K, and enthalpies of formation at O K for compounds of uranium, protactinium, thorium, actinium, lithium, sodium, potassium, rubidium, cesium, and francium.

  6. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

  7. Chemical reactions identified in the Titan 2, Titan 4, and Delta 2 propellant systems and their application to source modeling

    NASA Astrophysics Data System (ADS)

    Prince, S. P.; Banning, D. W.; Wiseman, F. L.

    1994-08-01

    A series of tests involving the combustion of solid and liquid propellants used to fuel the Titan 2, Titan 4, and Delta 2 launch vehicles was performed. The purpose of these tests was to evaluate the nature and amounts of combustion gases from reacting these propellants in various proportions, and to apply the derived data to predicting toxic chemical emissions arising from a launch vehicle explosion. Propellants tested in this study included Aerozine-50 and nitrogen tetroxide (liquid propellants used in the Titan 2 and Titan 4 launch vehicles), PBAN solid propellant (used on the Titan 4 solid rocket motor), RP-1 and liquid oxygen (liquid propellants used to fuel the Delta 2 launch vehicle), and the Castor IVA solid rocket propellant used on the Delta 2 first stage engine. Tests were conducted in a 150-liter stainless steel combustion chamber in air at nominal pressure (0.8 atmospheres at Denver barometric conditions). Measurements of the chamber gas temperature and internal pressure were taken and gas samples were withdrawn and analyzed for expected combustion gases, unreacted propellants, organic vapors, and oxygen reacted from the air. A stainless steel witness plate was used to collect condensates which formed during the course of the propellant combustion tests. Results of this study suggest significantly different chemical fates for some of the rocket propellants than those predicted by chemical theory only. A description of the test parameters, results, and application to source predictions is presented.

  8. Identifying depositional environments of chert using chemical techniques: An overview of general principles and a synthesis of 45 published results

    SciTech Connect

    Murray, R.W. . Graduate School of Oceanography)

    1992-01-01

    Chemical approaches have their own limitations, reflecting analytical and interpretational constraints (due to the extremely high Si concentrations), as well as the potential for diagenetic resetting of the environmental signature. The effect of diagenesis is non-recoverable; for example, chemical fractionation during chert formation strictly precludes use of Si, Ca, Mg, P, Mn, Sr, and Ba, due to their affiliations with unstable biogenic phases. Thus, in many cases there are discouragingly few elements from which to choose an appropriate set of chemical criteria. The author has synthesized published results of major, trace, and rare earth element (REE) data from 45 chert sequences from Early Paleozoic to Neogene continental margin, pelagic, and ridge-proximal environments. The author presents a set of depositional criteria that allow for the analytical and diagenetic limitations inherent to the chemistry of chert, and which should be applicable to cherts regardless of their age, local diagenetic history, or tectonic region. Major element ratios, capitalizing on the affiliations of Al and Ti to terrigenous matter and of Fe to metalliferous input, yield reasonable criteria for distinguishing continental margin from ridge-proximal sedimentation, but cannot delineate pelagic deposition. Trace element data indicate that Zr and Cr in continental margin cherts are significantly lower than would be expected from their affiliation with detrital heavy minerals, and seem on average similar to values from pelagic and ridge-proximal cherts. Intra-REE ratios (e.g., the Ce anomaly) resolve all three depositional regimes and are independent of diagenetic modification.

  9. Identifying potential endocrine disruptors among industrial chemicals and their metabolites--development and evaluation of in silico tools.

    PubMed

    Rybacka, Aleksandra; Rudén, Christina; Tetko, Igor V; Andersson, Patrik L

    2015-11-01

    The aim of this study was to improve the identification of endocrine disrupting chemicals (EDCs) by developing and evaluating in silico tools that predict interactions at the estrogen (E) and androgen (A) receptors, and binding to transthyretin (T). In particular, the study focuses on evaluating the use of the EAT models in combination with a metabolism simulator to study the significance of bioactivation for endocrine disruption. Balanced accuracies of the EAT models ranged from 77-87%, 62-77%, and 65-89% for E-, A-, and T-binding respectively. The developed models were applied on a set of more than 6000 commonly used industrial chemicals of which 9% were predicted E- and/or A-binders and 1% were predicted T-binders. The numbers of E- and T-binders increased 2- and 3-fold, respectively, after metabolic transformation, while the number of A-binders marginally changed. In-depth validation confirmed that several of the predicted bioactivated E- or T-binders demonstrated in vivo estrogenic activity or influenced blood levels of thyroxine in vivo. The metabolite simulator was evaluated using in vivo data from the literature which showed a 50% accuracy for studied chemicals. The study stresses, in summary, the importance of including metabolic activation in prioritization activities of potentially emerging contaminants. PMID:26210185

  10. Profiling of the Tox21 Chemical Collection for Mitochondrial Function: I. Compounds that Decrease Mitochondrial Membrane Potential

    EPA Science Inventory

    Mitochondrial dysfunction has been implicated in the pathogenesis of a variety of disorders including cancer, diabetes, and neurodegenerative and cardiovascular diseases. Understanding how different environmental chemicals and drug-like molecules impact mitochondrial function rep...

  11. Application of bicyclic and cage compounds

    NASA Technical Reports Server (NTRS)

    Clark, R. D.; Archuleta, B. S.

    1976-01-01

    The results of a literature survey of the field of bicyclic and cage compounds were presented, with the objective of identifying those types of compounds with unusual physical and chemical stability, and determining what practical applications have been found for these compounds. Major applications have been as polymers, polymer additives, medicinals, and pesticides. Lesser applications have included fuels, fuel additives, lubricants, lubricant additives, and perfumes. Several areas where further work might be useful were also outlined; these are primarily in the areas of polymers, polymer additives, medicinals, and synthetic lubricants.

  12. Dioxins and dioxin-like compounds in composts and digestates from European countries as determined by the in vitro bioassay and chemical analysis.

    PubMed

    Beníšek, Martin; Kuku?ka, Petr; Mariani, Giulio; Suurkuusk, Gert; Gawlik, Bernd M; Locoro, Giovanni; Giesy, John P; Bláha, Lud?k

    2015-03-01

    Aerobic composting and anaerobic digestion plays an important role in reduction of organic waste by transforming the waste into humus, which is an excellent soil conditioner. However, applications of chemical-contaminated composts on soils may have unwanted consequences such as accumulation of persistent compounds and their transfer into food chains. The present study investigated burden of composts and digestates collected in 16 European countries (88 samples) by the compounds causing dioxin-like effects as determined by use of an in vitro transactivation assay to quantify total concentrations of aryl hydrocarbon receptor-(AhR) mediated potency. Measured concentrations of 2,3,7,8-Tetrachlorodibeno-p-dioxin (2,3,7,8-TCDD) equivalents (TEQbio) were compared to concentrations of polycyclic aromatic hydrocarbons (PAHs) and selected chlorinated compounds, including polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), co-planar polychlorinated biphenyls (PCBs), indicator PCB congeners and organochlorine pesticides (OCPs). Median concentrations of TEQbio (dioxin-like compounds) determined by the in vitro assay in crude extracts of various types of composts ranged from 0.05 to 1.2 with a maximum 8.22?g (TEQbio)kg(-1) dry mass. Potencies were mostly associated with less persistent compounds such as PAHs because treatment with sulfuric acid removed bioactivity from most samples. The pan-European investigation of contamination by organic contaminants showed generally good quality of the composts, the majority of which were in compliance with conservative limits applied in some countries. Results demonstrate performance and added value of rapid, inexpensive, effect-based monitoring, and points out the need to derive corresponding effect-based trigger values for the risk assessment of complex contaminated matrices such as composts. PMID:25522853

  13. idTarget: a web server for identifying protein targets of small chemical molecules with robust scoring functions and a divide-and-conquer docking approach.

    PubMed

    Wang, Jui-Chih; Chu, Pei-Ying; Chen, Chung-Ming; Lin, Jung-Hsin

    2012-07-01

    Identification of possible protein targets of small chemical molecules is an important step for unravelling their underlying causes of actions at the molecular level. To this end, we construct a web server, idTarget, which can predict possible binding targets of a small chemical molecule via a divide-and-conquer docking approach, in combination with our recently developed scoring functions based on robust regression analysis and quantum chemical charge models. Affinity profiles of the protein targets are used to provide the confidence levels of prediction. The divide-and-conquer docking approach uses adaptively constructed small overlapping grids to constrain the searching space, thereby achieving better docking efficiency. Unlike previous approaches that screen against a specific class of targets or a limited number of targets, idTarget screen against nearly all protein structures deposited in the Protein Data Bank (PDB). We show that idTarget is able to reproduce known off-targets of drugs or drug-like compounds, and the suggested new targets could be prioritized for further investigation. idTarget is freely available as a web-based server at http://idtarget.rcas.sinica.edu.tw. PMID:22649057

  14. Mass-dependent and Mass-independent Sulphur Isotope Fractionation Accompanying Thermal- and Photo-chemical Decomposition of Sulphur Bearing Organic Compounds

    NASA Astrophysics Data System (ADS)

    Oduro, Harry; Izon, Gareth; Ono, Shuhei

    2014-05-01

    The bimodal S-isotope record, specifically the transition from mass independent (MIF) to mass dependent fractionation (MDF), is perhaps the most widely cited line of evidence for an irreversible rise in atmospheric oxygen at ca. 2.4Ga. The production and preservation of S-MIF, manifested in both ?33S and ?36S, within the geological record are linked to atmospheric O2 via a number of arguments. However, to date, the only mechanism capable of generating S-MIF consistent with the Archaean sedimentary records involves gas-phase ultraviolet irradiation of SO21 photolysis. More recently, ?33S S-MIF trends have been reported from en vitro thermochemical sulphate reduction (TSR) experiments, prompting authors to question the importance of S-MIF as a proxy for Earth oxidation2. Importantly, whilst emerging TSR experiments3,4 affirm the reported ?33S trends2, these experiments fail to identify correlated S-MIF between ?33S and ?36S values3,4. Realization that S-MIF is confined to ?33S during TSR, precludes TSR as a mechanism responsible for the origin of the Archaean S-MIF record but strongly suggests the effect originating from a magnetic isotope effect (MIE) associated with 33S nucleus3,4. Clearly, photochemical and thermochemical processes impart different ?36S/?33S trends with significant variation in ?34S; however, a complete experimental elucidation of mechanisms responsible for the S-MIF and S-MIE signatures is lacking. Interestingly, a complete understanding of the S-isotope chemistry during thermal- and photo-chemical decomposition may reveal wavelength and thermal dependence archived in the sedimentary record. Here we extend the experimental database to explore the magnitude and sign of ?36S/?33S and ?34S produced during both photo- and thermochemical processes. Here the organic sulphur compounds (OSC) utilized in these experiments carries diagnostic ?36S/?33S patterns that differ from those reported from photolysis experiment SO2 and from the Archaean sedimentary record. Further thermal decomposition of several sulphur containing compounds with; 1) an aliphatic-S (e.g., diphenyl disulphide), 2) tri-substituted aromatic-S (trithiane), and S-amino acids (e.g., cysteine, methionine, taurine, and glutathionine) were tested for four S-isotope fractionation under vacuum. Among these, aromatic trithiane produced anomalous 33S up to 1.3‰, indicating thermal decomposition through radical chemistry, producing S-MIE. While taurine with sulphonic acid (R-SO2OH) functional groups yielded S-MDF up to 15‰ (between the AVS and the residual OSC), which is consistent with estimated zero-point energy shifts for thiol (R-SH), and thiyl (R-S-CH3) groups of cysteine and methionine, respectively. These results suggest that OSC might undergo either thermal or photochemical decomposition and the S-MIF, S-MDF, and S-MIE signatures may be archived in the geologic record. The emerging mechanisms responsible for these isotope signals and their implications will be discussed in more detail. Ultimately this work offers a framework where these signals can be used as a diagnostic marker to distinguish between thermo- and photochemical processes. References: 1. Farquhar et al., Science 2000 2. Watanabe et al., Science 2010; 3. Oduro et al., PNAS 2011; 4. Kopf and Ono, GCA 2012.

  15. 76 FR 63304 - Guidance for Industry on Incorporation of Physical-Chemical Identifiers Into Solid Oral Dosage...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-12

    ... labeling in a future guidance. In the Federal Register of July 14, 2009 (74 FR 34021), FDA announced the... Identifiers Into Solid Oral Dosage Form Drug Products for Anticounterfeiting; Availability AGENCY: Food and... Into Solid Oral Dosage Form Drug Products for Anticounterfeiting.'' This guidance...

  16. Major carcinogenic pathways identified by gene expression analysis of peritoneal mesotheliomas following chemical treatment in F344 rats

    EPA Science Inventory

    This study was performed to characterize the gene expression profile and to identify the major carcinogenic pathways involved in rat peritoneal mesothelioma (RPM) formation following treatment of Fischer 344 rats with o-nitrotoluene (o-NT) or bromochloracetic acid (BCA). Oligo a...

  17. Chemical and biological methods for the analysis and remediation of environmental contaminants frequently identified at Superfund sites 

    E-print Network

    Wiles, Melinda Christine

    2004-11-15

    of chlorine substituents on specific congeners. Thus, this information may be used to identify and quantify unknown CPs in a mixture to be remediated. Due to the toxic effects observed due to CP exposure in vitro, the objective of the second study...

  18. Helleborus purpurascens-Amino Acid and Peptide Analysis Linked to the Chemical and Antiproliferative Properties of the Extracted Compounds.

    PubMed

    Segneanu, Adina-Elena; Grozescu, Ioan; Cziple, Florentina; Berki, Daniel; Damian, Daniel; Niculite, Cristina Mariana; Florea, Alexandru; Leabu, Mircea

    2015-01-01

    There is a strong drive worldwide to discover and exploit the therapeutic potential of a large variety of plants. In this work, an alcoholic extract of Helleborus purpurascens (family Ranunculaceae) was investigated for the identification of amino acids and peptides with putative antiproliferative effects. In our work, a separation strategy was developed using solvents of different polarity in order to obtain active compounds. Biochemical components were characterized through spectroscopic (mass spectroscopy) and chromatographic techniques (RP-HPLC and GC-MS). The biological activity of the obtained fractions was investigated in terms of their antiproliferative effects on HeLa cells. Through this study, we report an efficient separation of bioactive compounds (amino acids and peptides) from a plant extract dependent on solvent polarity, affording fractions with unaffected antiproliferative activities. Moreover, the two biologically tested fractions exerted a major antiproliferative effect, thereby suggesting potential anticancer therapeutic activity. PMID:26690401

  19. Chemical composition and antioxidant activity of phenolic compounds from wild and cultivated Sclerocarya birrea(Anacardiaceae) leaves.

    PubMed

    Braca, Alessandra; Politi, Matteo; Sanogo, Rokia; Sanou, Haby; Morelli, Ivano; Pizza, Cosimo; De Tommasi, Nunziatina

    2003-11-01

    A quantitative study of the phenolic constituents of wild and cultivated leaves of Sclerocarya birrea(Anacardiaceae) was carried out by HPLC-UV/PDA and LC-MS. Phytochemical analysis of the methanol extract of wild plants led to the isolation of one new flavonol glycoside, quercetin 3-O-alpha-l-(5' '-galloyl)-arabinofuranoside (1), and eight known phenolic compounds; two epicatechin derivatives were also isolated from the same extract of the cultivated species. The antioxidant activity of all isolated compounds was determined by measuring free radical scavenging effects using the Trolox equivalent antioxidant capacity assay and the coupled oxidation of beta-carotene and linoleic acid (autoxidation assay). PMID:14582961

  20. NMR analysis and chemical shift calculations of poly(lactic acid) dimer model compounds with different tacticities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this work, PLA dimer model compounds with different tacticities were synthesized and studied in detail by 1H and 13C NMR in three solvents, CDCl3/CCl4 (20/80 v/v), CDCl3 and DMSO-d6. All the peaks in the 1H and 13C NMR spectra were assigned with the help of two-dimensional NMR. Although the solve...

  1. Reduced weight decontamination formulation utilizing a solid peracid compound for neutralization of chemical and biological warfare agents

    SciTech Connect

    Tucker, Mark D.

    2011-09-20

    A reduced weight decontamination formulation that utilizes a solid peracid compound (sodium borate peracetate) and a cationic surfactant (dodecyltrimethylammonium chloride) that can be packaged with all water removed. This reduces the packaged weight of the decontamination formulation by .about.80% (as compared to the "all-liquid" DF-200 formulation) and significantly lowers the logistics burden on the warfighter. Water (freshwater or saltwater) is added to the new decontamination formulation at the time of use from a local source.

  2. Variability in Human Bitter Taste Sensitivity to Chemically Diverse Compounds Can Be Accounted for by Differential TAS2R Activation.

    PubMed

    Roura, Eugeni; Aldayyani, Asya; Thavaraj, Pridhuvi; Prakash, Sangeeta; Greenway, Delma; Thomas, Walter G; Meyerhof, Wolfgang; Roudnitzky, Natacha; Foster, Simon R

    2015-07-01

    The human population displays high variation in taste perception. Differences in individual taste sensitivity may also impact on nutrient intake and overall appetite. A well-characterized example is the variable perception of bitter compounds such as 6-n-propylthiouracil (PROP) and phenylthiocarbamide (PTC), which can be accounted for at the molecular level by polymorphic variants in the specific type 2 taste receptor (TAS2R38). This phenotypic variation has been associated with influencing dietary preference and other behaviors, although the generalization of PROP/PTC taster status as a predictor of sensitivity to other tastes is controversial. Here, we proposed that the taste sensitivities of different bitter compounds would be correlated only when they activate the same bitter taste receptor. Thirty-four volunteers were exposed to 8 bitter compounds that were selected based on their potential to activate overlapping and distinct repertoires of TAS2Rs. Taste intensity ratings were evaluated using the general Labeled Magnitude Scale. Our data demonstrate a strong interaction between the intensity for bitter substances when they activate common TAS2Rs. Consequently, PROP/PTC sensitivity was not a reliable predictor of general bitter sensitivity. In addition, our findings provide a novel framework to predict taste sensitivity based on their specific T2R activation profile. PMID:25999325

  3. Physico-chemical parameters, bioactive compounds and microbial quality of thermo-sonicated carrot juice during storage.

    PubMed

    Martínez-Flores, Héctor E; Garnica-Romo, Ma Guadalupe; Bermúdez-Aguirre, Daniela; Pokhrel, Prashant Raj; Barbosa-Cánovas, Gustavo V

    2015-04-01

    Thermosonication has been successfully tested in food for microbial inactivation; however, changes in bioactive compounds and shelf-life of treated products have not been thoroughly investigated. Carrot juice was thermo-sonicated (24 kHz, 120 ?m amplitude) at 50 °C, 54 °C and 58 °C for 10 min (acoustic power 2204.40, 2155.72, 2181.68 mW/mL, respectively). Quality parameters and microbial growth were evaluated after processing and during storage at 4 °C. Control and sonicated treatments at 50 °C and 54 °C had 10, 12 and 14 d of shelf-life, respectively. Samples sonicated at 58 °C had the best quality; microbial growth remained low at around 3-log for mesophiles, 4.5-log for yeasts and molds and 2-log for enterobacteria after 20 d of storage. Furthermore, thermo-sonicated juice at 58 °C retained >98% of carotenoids and 100% of ascorbic acid. Phenolic compounds increased in all stored, treated juices. Thermo-sonication is therefore a promising technology for preserving the quality of carrot juice by minimising the physicochemical changes during storage, retarding microbial growth and retaining the bioactive compounds. PMID:25442602

  4. Differences in the in vitro susceptibility to resveratrol and other chemical compounds among several Philasterides dicentrarchi isolates from turbot.

    PubMed

    Budiño, B; Pata, M P; Leiro, J; Lamas, J

    2012-04-01

    Philasterides dicentrarchi is a histophagous scuticociliate that causes important losses in aquaculture. Several strains that differ in morphological, genetic and serological characteristics and virulence have been isolated from outbreaks of turbot scuticociliatosis. In the present study, seven isolates of the ciliate were exposed in vitro to formalin, hydrogen peroxide and resveratrol (a phytoalexin produced by plants) in order to evaluate the susceptibility of the isolates to the different compounds. The LD50 values for the three compounds tested varied widely among the isolates. The LD100 values were similar among isolates for formalin (25-30 ppm) and resveratrol (60-70 ppm) but were very different for hydrogen peroxide (25->80 ppm). The results indicate that there are many physiological differences among isolates and even among specimens of the same isolates, which must be taken into account in designing control programmes. The naturally occurring resveratrol may be a good alternative to other compounds for reducing the amounts of viable ciliates in water. PMID:21987103

  5. A chemical genetic strategy identify the PHOSTIN, a synthetic molecule that triggers phosphate starvation responses in Arabidopsis thaliana.

    PubMed

    Bonnot, Clémence; Pinson, Benoît; Clément, Mathilde; Bernillon, Stéphane; Chiarenza, Serge; Kanno, Satomi; Kobayashi, Natsuko; Delannoy, Etienne; Nakanishi, Tomoko M; Nussaume, Laurent; Desnos, Thierry

    2016-01-01

    Plants display numerous strategies to cope with phosphate (Pi)-deficiency. Despite multiple genetic studies, the molecular mechanisms of low-Pi-signalling remain unknown. To validate the interest of chemical genetics to investigate this pathway we discovered and analysed the effects of PHOSTIN (PSN), a drug mimicking Pi-starvation in Arabidopsis. We assessed the effects of PSN and structural analogues on the induction of Pi-deficiency responses in mutants and wild-type and followed their accumulation in plants organs by high pressure liquid chromotography (HPLC) or mass-spectrophotometry. We show that PSN is cleaved in the growth medium, releasing its active motif (PSN11), which accumulates in plants roots. Despite the overaccumulation of Pi in the roots of treated plants, PSN11 elicits both local and systemic Pi-starvation effects. Nevertheless, albeit that the transcriptional activation of low-Pi genes by PSN11 is lost in the phr1;phl1 double mutant, neither PHO1 nor PHO2 are required for PSN11 effects. The range of local and systemic responses to Pi-starvation elicited, and their dependence on the PHR1/PHL1 function suggests that PSN11 affects an important and early step of Pi-starvation signalling. Its independence from PHO1 and PHO2 suggest the existence of unknown pathway(s), showing the usefulness of PSN and chemical genetics to bring new elements to this field. PMID:26243630

  6. Technical Note: Performance of Chemical Ionization Reaction Time-of-Flight Mass Spectrometry (CIR-TOF-MS) for the measurement of atmospherically significant oxygenated volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Wyche, K. P.; Blake, R. S.; Ellis, A. M.; Monks, P. S.; Brauers, T.; Koppmann, R.; Apel, E. C.

    2007-02-01

    The performance of a new chemical ionization reaction time-of-flight mass spectrometer (CIR-TOF-MS) utilising the environment chamber SAPHIR (Simulation of Atmospheric Photochemistry In a large Reaction Chamber- Forschungzentrum Jülich, Germany) is described. The work took place as part of the ACCENT (Atmospheric Composition and Change the European NeTwork for excellence) supported oxygenated volatile organic compound (OVOC) measurement intercomparison during January 2005. The experiment entailed the measurement of 14 different atmospherically significant OVOCs at various mixing ratios in the approximate range 10.0-0.6 ppbV. The CIR-TOF-MS operated throughout the exercise with the hydronium ion (H3O+) as the primary chemical ionization (CI) reagent in order to facilitate proton transfer to the analyte OVOCs. The results presented show that the CIR time-of-flight mass spectrometer is capable of detecting a wide range of atmospheric OVOCs at mixing ratios of around 10 ppbV in "real-time" (i.e. detection on the one-minute time scale), with sub-ppbV measurement also achieved following an increase in averaging time to tens of minutes. It is shown that in general OVOC measurement is made with high accuracy and precision, with integration time, mixing ratio and compound dependent values as good as 4-13% and 3-15% respectively. It is demonstrated that CIR-TOF-MS has rapid multi-channel response at the required sensitivity, accuracy and precision for atmospheric OVOC measurement.

  7. Computational and Experimental Assessment of Benzene Cation Chemistry for the Measurement of Marine Derived Biogenic Volatile Organic Compounds with Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Zoerb, M.; Kim, M.; Zimmermann, K.; Bertram, T. H.

    2013-12-01

    Chemical ionization mass spectrometry (CIMS) is a highly selective and sensitive technique for the measurement of trace gases in the atmosphere. However, competing side reactions and dependence on relative humidity (RH) can make the transition from the laboratory to the field challenging. Effective implementation of chemical ionization requires a thorough knowledge of the elementary steps leading to ionization of the analyte. We have recently investigated benzene cations for the detection of marine derived biogenic volatile organic compounds (BVOCs), such isoprene and terpene compounds, from algal bloom events. Our experimental results indicate that benzene ion chemistry is an attractive candidate for field measurements, and the RH dependence is weak. To further understand the advantages and limitations of this approach, we have also used electronic structure theory calculations to compliment the experimental work. These theoretical methods can provide valuable insight into the physical chemistry of ion molecule reactions including thermodynamical information, the stability of ions to fragmentation, and potential sources of interference such as dehydration to form isobaric ions. The combined experimental and computational approach also allows validation of the theoretical methods and will provide useful information towards gaining predictive power for the selection of appropriate reagent ions for future experiments.

  8. Chemical microsensors

    SciTech Connect

    Li, DeQuan; Swanson, Basil I.

    1995-01-01

    An article of manufacture is provided including a substrate having an oxide surface layer and a selective thin film of a cyclodextrin derivative chemically bound upon said substrate, said film is adapted for the inclusion of a selected organic compound therewith. Such an article can be either a chemical sensor capable of detecting a resultant mass change from inclusion of the selected organic compound or a chemical separator capable of reversibly selectively separating a selected organic compound.

  9. A chemical genetic screen in Mycobacterium tuberculosis identifies carbon-source-dependent growth inhibitors devoid of in vivo efficacy

    PubMed Central

    Pethe, Kevin; Sequeira, Patricia C.; Agarwalla, Sanjay; Rhee, Kyu; Kuhen, Kelli; Phong, Wai Yee; Patel, Viral; Beer, David; Walker, John R.; Duraiswamy, Jeyaraj; Jiricek, Jan; Keller, Thomas H.; Chatterjee, Arnab; Tan, Mai Ping; Ujjini, Manjunatha; Rao, Srinivasa P.S.; Camacho, Luis; Bifani, Pablo; Mak, Puiying A.; Ma, Ida; Barnes, S. Whitney; Chen, Zhong; Plouffe, David; Thayalan, Pamela; Ng, Seow Hwee; Au, Melvin; Lee, Boon Heng; Tan, Bee Huat; Ravindran, Sindhu; Nanjundappa, Mahesh; Lin, Xiuhua; Goh, Anne; Lakshminarayana, Suresh B.; Shoen, Carolyn; Cynamon, Michael; Kreiswirth, Barry; Dartois, Veronique; Peters, Eric C.; Glynne, Richard; Brenner, Sydney; Dick, Thomas

    2010-01-01

    Candidate antibacterials are usually identified on the basis of their in vitro activity. However, the apparent inhibitory activity of new leads can be misleading because most culture media do not reproduce an environment relevant to infection in vivo. In this study, while screening for novel anti-tuberculars, we uncovered how carbon metabolism can affect antimicrobial activity. Novel pyrimidine–imidazoles (PIs) were identified in a whole-cell screen against Mycobacterium tuberculosis. Lead optimization generated in vitro potent derivatives with desirable pharmacokinetic properties, yet without in vivo efficacy. Mechanism of action studies linked the PI activity to glycerol metabolism, which is not relevant for M. tuberculosis during infection. PIs induced self-poisoning of M. tuberculosis by promoting the accumulation of glycerol phosphate and rapid ATP depletion. This study underlines the importance of understanding central bacterial metabolism in vivo and of developing predictive in vitro culture conditions as a prerequisite for the rational discovery of new antibiotics. PMID:20975714

  10. Unbiased Screening of Marine Sponge Extracts for Anti-Inflammatory Agents Combined with Chemical Genomics Identifies Girolline as an Inhibitor of Protein Synthesis

    PubMed Central

    Fung, Shan-Yu; Sofiyev, Vladimir; Schneiderman, Julia; Hirschfeld, Aaron F.; Victor, Rachel E.; Woods, Kate; Piotrowski, Jeff S.; Deshpande, Raamesh; Li, Sheena C.; de Voogd, Nicole J.; Myers, Chad L.; Boone, Charlie; Andersen, Raymond J.; Turvey, Stuart E.

    2013-01-01

    Toll-like receptors (TLRs) play a critical role in innate immunity, but activation of TLR signaling pathways is also associated with many harmful inflammatory diseases. Identification of novel anti-inflammatory molecules targeting TLR signaling pathways is central to the development of new treatment approaches for acute and chronic inflammation. We performed high throughput screening from crude marine sponge extracts on TLR5 signaling and identified girolline. We demonstrated that girolline inhibits signaling through both MyD88-dependent and –independent TLRs (i.e. TLR2, 3, 4, 5 and 7), and reduces cytokine (IL-6 and IL-8) production in human peripheral blood mononuclear cells and macrophages. Using a chemical genomics approach, we identified Elongation factor 2 as the molecular target of girolline, which inhibits protein synthesis at the elongation step. Together these data identify the sponge natural product girolline as a potential anti-inflammatory agent acting through inhibition of protein synthesis. PMID:24117378

  11. Chemical and Synthetic Genetic Array Analysis Identifies Genes that Suppress Xylose Utilization and Fermentation in Saccharomyces cerevisiae

    PubMed Central

    Usher, Jane; Balderas-Hernandez, Victor; Quon, Peter; Gold, Nicholas D.; Martin, Vincent J. J.; Mahadevan, Radhakrishnan; Baetz, Kristin

    2011-01-01

    Though highly efficient at fermenting hexose sugars, Saccharomyces cerevisiae has limited ability to ferment five-carbon sugars. As a significant portion of sugars found in cellulosic biomass is the five-carbon sugar xylose, S. cerevisiae must be engineered to metabolize pentose sugars, commonly by the addition of exogenous genes from xylose fermenting fungi. However, these recombinant strains grow poorly on xylose and require further improvement through rational engineering or evolutionary adaptation. To identify unknown genes that contribute to improved xylose fermentation in these recombinant S. cerevisiae, we performed genome-wide synthetic interaction screens to identify deletion mutants that impact xylose utilization of strains expressing the xylose isomerase gene XYLA from Piromyces sp. E2 alone or with an additional copy of the endogenous xylulokinase gene XKS1. We also screened the deletion mutant array to identify mutants whose growth is affected by xylose. Our genetic network reveals that more than 80 nonessential genes from a diverse range of cellular processes impact xylose utilization. Surprisingly, we identified four genes, ALP1, ISC1, RPL20B, and BUD21, that when individually deleted improved xylose utilization of both S. cerevisiae S288C and CEN.PK strains. We further characterized BUD21 deletion mutant cells in batch fermentations and found that they produce ethanol even the absence of exogenous XYLA. We have demonstrated that the ability of laboratory strains of S. cerevisiae to utilize xylose as a sole carbon source is suppressed, which implies that S. cerevisiae may not require the addition of exogenous genes for efficient xylose fermentation. PMID:22384336

  12. Spatial Variation of Aerosol Chemical Composition and Organic Components Identified by Positive Matrix Factorization in the Barcelona Region.

    PubMed

    Mohr, Claudia; DeCarlo, Peter F; Heringa, Maarten F; Chirico, Roberto; Richter, René; Crippa, Monica; Querol, Xavier; Baltensperger, Urs; Prévôt, André S H

    2015-09-01

    The spatial distribution of PM1 components in the Barcelona metropolitan area was investigated using on-road mobile measurements of atmospheric particle- and gas-phase compounds during the DAURE campaign in March 2009. Positive matrix factorization (PMF) applied to organic aerosol (OA) data yielded 5 factors: hydrocarbon-like OA (HOA), cooking OA (COA), biomass burning OA (BBOA), and low volatility and semivolatile oxygenated OA (LV-OOA and SV-OOA). The area under investigation (?500 km(2)) was divided into six zones (city center, harbor, industrial area, precoastal depression, 2 mountain ranges) for measurements and data analysis. Mean zonal OA concentrations are 4.9-9.5 ?g m(-3). The area is heavily impacted by local primary emissions (HOA 14-38%, COA 10-18%, BBOA 10-12% of OA); concentrations of traffic-related components, especially black carbon, are biased high due to the on-road nature of the measurements. The formation of secondary OA adds more than half of the OA burden outside the city center (SV-OOA 14-40%, LV-OOA 17-42% of OA). A case study of one measurement drive from the shore to the precoastal mountain range furthest downwind of the city center indicates the importance of nonfossil over anthropogenic secondary OA based on OA/CO. PMID:26237368

  13. Comparison of electron and chemical ionization modes for the quantification of thiols and oxidative compounds in white wines by gas chromatography-tandem mass spectrometry.

    PubMed

    Thibon, Cécile; Pons, Alexandre; Mouakka, Nadia; Redon, Pascaline; Méreau, Raphaël; Darriet, Philippe

    2015-10-01

    A rapid, sensitive method for assaying volatile impact compounds in white wine was developed using gas chromatography-tandem mass spectrometry (GC-MS/MS) technology, with a triple quadrupole analyzer operating in chemical ionization and electron impact mode. This GC-MS/MS method made it possible to assay volatile thiols (3SH: 3-sulfanylhexanol, formerly 3MH; 3SHA: 3-sulfanylhexyl acetate, formerly 3MHA; 4MSP: 4-methyl-4-sulfanylpentan-2-one, formerly 4MMP; BM: benzenemethanethiol; E2SA: ethyl 2-sulfanylacetate; and 2FM: 2-furanmethanethiol) and odoriferous oxidation markers (Sotolon: 4,5-dimethyl-3-hydroxy-2(5)H-furanone, methional, and phenylacetaldehyde) simultaneously in dry white wines, comparing electron impact (EI) and chemical ionization (CI) modes. More molecular ions were produced by CI than protonated molecules, despite the greater fragmentation caused by EI. So, even using the best reactant gas giving the highest signal for thiols, EI was the best ionization mode, with the lowest detection limits. For all compounds of interest, the limits of quantification (LOQ) obtained were well below their detection thresholds (ranging from 0.5 to 8.5ng/L for volatile thiols and 65-260ng/L for oxidation markers). Recovery rates ranged from 86% to 111%, reproducibility (in terms of relative standard deviation; RSD) was below 18% in all cases, with correlation coefficients above 0.991 for all analytes. The method was successfully applied to the analysis of compounds of interest in Sauvignon Blanc wines from a single estate and ten different vintages. PMID:26358562

  14. Mortality study of workers in 1,3-butadiene production units identified from a chemical workers cohort.

    PubMed Central

    Ward, E M; Fajen, J M; Ruder, A M; Rinsky, R A; Halperin, W E; Fessler-Flesch, C A

    1995-01-01

    The International Agency for Research on Cancer has given the designations of "sufficient evidence" of carcinogenicity of 1,3-butadiene in experimental animals and "limited evidence" of carcinogenicity in humans. To investigate the carcinogenic effect in humans, we conducted a cohort mortality study among 364 men who were assigned to any of three 1,3-butadiene production units located within several chemical plants in the Kanawha Valley of West Virginia, including 277 men employed in a U.S. Rubber Reserve Plant which operated during World War II. The butadiene production units included in this study were selected from an index developed by the Union Carbide Corporation, which listed for each chemical production unit within their South Charleston, West Virginia and Institute, West Virginia, plants all products, by-products, and reactants. Departments included in the study were those where butadiene was a primary product and neither benzene nor ethylene oxide was present. A total of 185 deaths were observed; the standardized mortality ratio (SMR) for all causes of death was 91, reflecting lower mortality among the study population than the U.S. population. The study found a significantly elevated standardized mortality ratio (SMR) for lymphosarcoma and reticulosarcoma based on four observed cases (SMR = 577; 95% CI = 157-1480), which persisted in an analysis using county referent rates. An excess of lymphosarcoma and reticulosarcoma among all workers and among workers with routine exposure to 1,3-butadiene was also observed in the only other cohort of 1,3-butadiene production workers previously studied.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7556014

  15. BIOASSAY-DIRECTED CHEMICAL ANALYSIS OF ORGANIC EXTRACTS OF EMISSIONS FROM A LABORATORY-SCALE INCINERATOR: COMBUSTION OF SURROGATE COMPOUNDS

    EPA Science Inventory

    The paper describes using a prototype/pilot-scale rotary kiln (73 kill) to examine the chemical composition and biological effect's of emissions produced when operating the kiln under suboptimal conditions resulting from batch charging. he surrogate wastes evaluated included comb...

  16. Nitroaromatic Compounds, from Synthesis to Biodegradation

    PubMed Central

    Ju, Kou-San; Parales, Rebecca E.

    2010-01-01

    Summary: Nitroaromatic compounds are relatively rare in nature and have been introduced into the environment mainly by human activities. This important class of industrial chemicals is widely used in the synthesis of many diverse products, including dyes, polymers, pesticides, and explosives. Unfortunately, their extensive use has led to environmental contamination of soil and groundwater. The nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalcitrance of these compounds to biodegradation. The electron-withdrawing nature of the nitro group, in concert with the stability of the benzene ring, makes nitroaromatic compounds resistant to oxidative degradation. Recalcitrance is further compounded by their acute toxicity, mutagenicity, and easy reduction into carcinogenic aromatic amines. Nitroaromatic compounds are hazardous to human health and are registered on the U.S. Environmental Protection Agency's list of priority pollutants for environmental remediation. Although the majority of these compounds are synthetic in nature, microorganisms in contaminated environments have rapidly adapted to their presence by evolving new biodegradation pathways that take advantage of them as sources of carbon, nitrogen, and energy. This review provides an overview of the synthesis of both man-made and biogenic nitroaromatic compounds, the bacteria that have been identified to grow on and completely mineralize nitroaromatic compounds, and the pathways that are present in these strains. The possible evolutionary origins of the newly evolved pathways are also discussed. PMID:20508249

  17. Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

    NASA Astrophysics Data System (ADS)

    Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

    2004-01-01

    Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO 2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis, 1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project.

  18. Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

    NASA Technical Reports Server (NTRS)

    Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

    2004-01-01

    Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project. Published by Elsevier Ltd on behalf of COSPAR.

  19. Evaluation of food additives and low-toxicity compounds as alternative chemicals for the control of Penicillium digitatum and Penicillium italicum on citrus fruit.

    PubMed

    Palou, Lluís; Usall, Josep; Smilanick, Joseph L; Aguilar, Maria-José; Viñas, Inmaculada

    2002-05-01

    The effectiveness of low-toxicity chemicals as possible alternatives to synthetic fungicides for the control of post-harvest green and blue moulds of citrus was evaluated. A preliminary selection of chemicals, mostly common food additives, was made through in vivo primary screenings with oranges artificially inoculated with Penicillium digitatum or P italicum. Selected compounds and mixtures were tested as heated solutions in small-scale trials. Immersion of artificially inoculated oranges or lemons for 120 s in solutions at 40.6 degrees C and natural pH of potassium sorbate (0.2 M), sodium benzoate (0.2 M) or mixtures (0.1 + 0.1 M) of potassium sorbate with sodium benzoate, sodium propionate or sodium acetate were the most effective organic acid salts tested and reduced green mould by 70-80% after 7 days of storage at 20 degrees C. The mixtures did not significantly enhance the effectiveness of potassium sorbate or sodium benzoate alone. These solutions were as effective as sodium carbonate or calcium polysulphide treatments and, in general, they were more effective on lemons than on oranges. Satisfactory control of green and blue moulds was obtained by dipping oranges for 150 s in solutions of sodium molybdate (24.2 mM) or ammonium molybdate (1.0 mM) at 48 or 53 degrees C, but not at 20 degrees C. At 53 degrees C, however, the effectiveness of hot water was not enhanced by either molybdate. Molybdenum salts at higher concentrations were phytotoxic and stained the fruit. At non-phytotoxic concentrations, the effectiveness of these solutions was more influenced by temperature than by concentration. In general, the inhibitory effects of all compounds tested were not fungicidal but fungistatic and not very persistent. In conclusion, potassium sorbate, sodium benzoate and ammonium molybdate, among the wide range of chemicals tested, were superior for the control of post-harvest Penicillium decay of citrus fruit. PMID:11997972

  20. Coupling physical chemical techniques with hydrotalcite-like compounds to exploit their structural features and new multifunctional hybrids with luminescent properties.

    PubMed

    Costantino, Umberto; Costantino, Ferdinando; Elisei, Fausto; Latterini, Loredana; Nocchetti, Morena

    2013-08-28

    Hydrotalcite-like compounds (HTlc), belonging to the large class of Layered Double Hydroxides (LDH), have excited wide interest owing to the incredible number of their potential and achieved applications in physical, chemical and bio-chemical fields. This perspective review deals with recent advances in the application of physical-chemical techniques for the study of HTlc structure and for the design and synthesis, using intercalation chemistry routes, of new hybrid materials. Firstly, a rapid survey on the most common synthetic strategies for the attainment of HTlc with different crystallinity degree and crystal size and for their modification to obtain hybrids has been made, and the use of coupled techniques (XRPD, luminescence, Solid State MAS NMR and Molecular Dynamics) to gain structural information is reported. Then, the design, synthesis and photophysical characterization of azoic dyes-intercalated and co-intercalated HTlc hybrid materials are described. Hybrids constituted of ZnAl-HTlc, co-intercalated with stearate anions and methyl orange or methyl yellow dyes, have been used as nanofillers of hydrophobic polymers. The polymeric nano-composites obtained have been characterized by means of XRPD patterns, Thermo-Gravimetric Analysis and Confocal Fluorescence Microscopy. This latter technique has been found to be an excellent, complementary and non-invasive tool to probe the dispersion degree of the fluorescent fillers into the polymeric matrices and their stability in the compounding process. Finally, the synthesis and spectroscopic characterization of nanoparticle (NP) decorated HTlc for advanced antimicrobial and photo-catalytic applications are also reported. The review terminates with a concluding short note and future trends. PMID:23812233

  1. Lithium Ethylene Dicarbonate Identified as the Primary Product ofChemical and Electrochemical Reduction of EC in EC:EMC/1.2M LiPF6Electrolyte

    SciTech Connect

    Zhuang, Guorong V.; Xu, Kang; Yang, Hui; Jow, T. Richard; RossJr., Philip N.

    2005-05-11

    Lithium ethylene dicarbonate (CH2OCO2Li)2 was chemically synthesized and its Fourier Transform Infrared (FTIR) spectrum was obtained and compared with that of surface films formed on Ni after cyclic voltammetry (CV) in 1.2M lithium hexafluorophosphate(LiPF6)/ethylene carbonate (EC): ethyl methyl carbonate (EMC) (3:7, w/w) electrolyte and on metallic lithium cleaved in-situ in the same electrolyte. By comparison of IR experimental spectra with that of the synthesized compound, we established that the title compound is the predominant surface species in both instances. Detailed analysis of the IR spectrum utilizing quantum chemical (Hartree-Fock) calculations indicates that intermolecular association through O...Li...O interactions is very important in this compound. It is likely that the title compound in passivation layer has a highly associated structure, but the exact intermolecular conformation could not be established based on analysis of the IR spectrum.

  2. An approach to chemical freeze-out scenario of identified particle spectra at 200AGeV Au-Au collisions at RHIC

    E-print Network

    Wei-Liang Qian; Rone Andrade; Frederique Grassi; Yogiro Hama; Takeshi Kodama

    2007-09-06

    Thermal model fit indicates early chemical freeze-out of multi-strange hadrons with small collective velocities at 200AGeV Au-Au collisions at RHIC. In this work, we present our recent results by SPheRIO hydrodynamical calculations inspired by this picture. In our model, multi-strange hadrons go through chemical freeze-out when the system reaches some temperature close to the phase transition, stopping to make inelastic collisions, and their abundances are therefore determined only by partonic EOS. At a lower temperature thermal freeze-out takes place where elastic collisions are brought to a halt. We calculate the spectra for various hadrons at different centrality windows, with chemical and thermal freeze-out temperature being fit as a function of centrality. As it is shown, the result provides a reasonable panoramic description of the spectra of identified particles. Chemical freeze-out gives good correction of the multiplicity of certain species of particles, especially for multi-strange hadrons.

  3. Reliable disease biomarkers characterizing and identifying electrohypersensitivity and multiple chemical sensitivity as two etiopathogenic aspects of a unique pathological disorder.

    PubMed

    Belpomme, Dominique; Campagnac, Christine; Irigaray, Philippe

    2015-12-01

    Much of the controversy over the causes of electro-hypersensitivity (EHS) and multiple chemical sensitivity (MCS) lies in the absence of both recognized clinical criteria and objective biomarkers for widely accepted diagnosis. Since 2009, we have prospectively investigated, clinically and biologically, 1216 consecutive EHS and/or MCS-self reporting cases, in an attempt to answer both questions. We report here our preliminary data, based on 727 evaluable of 839 enrolled cases: 521 (71.6%) were diagnosed with EHS, 52 (7.2%) with MCS, and 154 (21.2%) with both EHS and MCS. Two out of three patients with EHS and/or MCS were female; mean age (years) was 47. As inflammation appears to be a key process resulting from electromagnetic field (EMF) and/or chemical effects on tissues, and histamine release is potentially a major mediator of inflammation, we systematically measured histamine in the blood of patients. Near 40% had a increase in histaminemia (especially when both conditions were present), indicating a chronic inflammatory response can be detected in these patients. Oxidative stress is part of inflammation and is a key contributor to damage and response. Nitrotyrosin, a marker of both peroxynitrite (ONOO°-) production and opening of the blood-brain barrier (BBB), was increased in 28% the cases. Protein S100B, another marker of BBB opening was increased in 15%. Circulating autoantibodies against O-myelin were detected in 23%, indicating EHS and MCS may be associated with autoimmune response. Confirming animal experiments showing the increase of Hsp27 and/or Hsp70 chaperone proteins under the influence of EMF, we found increased Hsp27 and/or Hsp70 in 33% of the patients. As most patients reported chronic insomnia and fatigue, we determined the 24 h urine 6-hydroxymelatonin sulfate (6-OHMS)/creatinin ratio and found it was decreased (<0.8) in all investigated cases. Finally, considering the self-reported symptoms of EHS and MCS, we serially measured the brain blood flow (BBF) in the temporal lobes of each case with pulsed cerebral ultrasound computed tomosphygmography. Both disorders were associated with hypoperfusion in the capsulothalamic area, suggesting that the inflammatory process involve the limbic system and the thalamus. Our data strongly suggest that EHS and MCS can be objectively characterized and routinely diagnosed by commercially available simple tests. Both disorders appear to involve inflammation-related hyper-histaminemia, oxidative stress, autoimmune response, capsulothalamic hypoperfusion and BBB opening, and a deficit in melatonin metabolic availability; suggesting a risk of chronic neurodegenerative disease. Finally the common co-occurrence of EHS and MCS strongly suggests a common pathological mechanism. PMID:26613326

  4. Isolation, identification, and antibacterial activity of chemical compounds from ethanolic extract of suji leaf (Pleomele angusifolia NE Brown)

    NASA Astrophysics Data System (ADS)

    Faridah; Natalia; Lina, Maria; W, Hendig

    2014-03-01

    Suji (Pleomele angustifolia NE Brown) is one of the medicinal plants of the tribe of Liliaceae, empirically useful to treat coughs and respiratory diseases such as tuberculosis (TB) and pneumonia. In this study, ethanolic extract of suji leaves was tested its activity against bacteria that attacks the respiratory organs, namely Mycobacterium tuberculosis and Streptococcus pneumoniae, using a paper disc diffusion and dilution agar method. These extracts have activity in inhibiting the growth of M. tuberculosis at a concentration of 8 mg and against S. pneumoniae at a concentration of 4 mg. The fractions were tested their antibacterial activity against Streptococcus pneumoniae using paper disc diffusion method. The most active fraction was chosen based on the inhibition diameter. The fractions contained flavonoids, steroids, and essential oils. The precipitate isolated from the extraction process shows needle-shaped, white, cold and tasteless crystals. Moreover, the HPLC analysis of isolate revealed a single peak with a retention time of 7.183 minutes. The exact compounds in the isolate could not be determined but it was known the compounds contained the functional groups of alkene, alkane, C=O, -OH. Test results obtained from UV-Vis spectrophotometer provides maximum absorption at a wavelength of 203.0 nm.

  5. PGVL Hub: An integrated desktop tool for medicinal chemists to streamline design and synthesis of chemical libraries and singleton compounds.

    PubMed

    Peng, Zhengwei; Yang, Bo; Mattaparti, Sarathy; Shulok, Thom; Thacher, Thomas; Kong, James; Kostrowicki, Jaroslav; Hu, Qiyue; Na, James; Zhou, Joe Zhongxiang; Klatte, David; Chao, Bo; Ito, Shogo; Clark, John; Sciammetta, Nunzio; Coner, Bob; Waller, Chris; Kuki, Atsuo

    2011-01-01

    PGVL Hub is an integrated molecular design desktop tool that has been developed and globally deployed throughout Pfizer discovery research units to streamline the design and synthesis of combinatorial libraries and singleton compounds. This tool supports various workflows for design of singletons, combinatorial libraries, and Markush exemplification. It also leverages the proprietary PGVL virtual space (which contains 10(14) molecules spanned by experimentally derived synthesis protocols and suitable reactants) for lead idea generation, lead hopping, and library design. There had been an intense focus on ease of use, good performance and robustness, and synergy with existing desktop tools such as ISIS/Draw and SpotFire. In this chapter we describe the three-tier enterprise software architecture, key data structures that enable a wide variety of design scenarios and workflows, major technical challenges encountered and solved, and lessons learned during its development and deployment throughout its production cycles. In addition, PGVL Hub represents an extendable and enabling platform to support future innovations in library and singleton compound design while being a proven channel to deliver those innovations to medicinal chemists on a global scale. PMID:20981530

  6. The origins of light and heavy r-process elements identified by chemical tagging of metal-poor stars

    E-print Network

    Tsujimoto, Takuji

    2014-01-01

    Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration gamma-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A>130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process pr...

  7. Chemical modification and pH dependence of kinetic parameters to identify functional groups in a glucosyltransferase from Strep. Mutans

    SciTech Connect

    Bell, J.E.; Leone, A.; Bell, E.T.

    1986-05-01

    A glucosyltransferase, forming a predominantly al-6 linked glucan, was partially purified from the culture filtrate of S. mutans GS-5. The kinetic properties of the enzyme, assessed using the transfer of /sup 14/C glucose from sucrose into total glucan, were studied at pH values from pH 3.5 to 6.5. From the dependence of km on pH, a group with pKa = 5.5 must be protonated to maximize substrate binding. From plots of V/sub max/ vs pH two groups, with pKa's of 4.5 and 5.5 were indicated. The results suggest the involvement of either two carboxyl groups (one protonated, one unprotonated in the native enzyme) or a carboxyl group (unprotonated) and some other protonated group such as histidine, cysteine. Chemical modification studies showed that Diethylyrocarbonate (histidine specific) had no effect on enzyme activity while modification with p-phydroxy-mercuribenzoate or iodoacetic acid (sulfhydryl reactive) and carbodimide reagents (carboxyl specific) resulted in almost complete inactivation. Activity loss was dependent upon time of incubation and reagent concentration. The disaccharide lylose, (shown to be an inhibitor of the enzyme with similar affinity to sucrose) offers no protection against modification by the sulfhydryl reactive reagents.

  8. Propolis Standardized Extract (EPP-AF®), an Innovative Chemically and Biologically Reproducible Pharmaceutical Compound for Treating Wounds

    PubMed Central

    Berretta, Andresa Aparecida; Nascimento, Andresa Piacezzi; Bueno, Paula Carolina Pires; de Oliveira Lima Leite Vaz, Mirela Mara; Marchetti, Juliana Maldonado

    2012-01-01

    The aim of this study was to develop a formulation, containing the propolis standardized extract (EPP-AF®), which can assist in the healing of skin lesions. To achieve this objective the antimicrobial activity and chemical composition of the propolis extract was determined. The final product was subjected to in vitro and in vivo pre-clinical evaluation. The broth macrodilution method was used to determine the antimicrobial activity of the extracts and formulations against the microorganisms most commonly found in burns, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis. Wistar rats with puncture wounded skin were used to evaluate the wound healing properties of propolis. The results of chemical and biological characterization demonstrated the batch-to-batch reproducibility of the standardized extract which is an unprecedented result. The antimicrobial and wound healing activity of the pharmaceutical studied showed the best results when samples contain 3.6% propolis, suggesting that this is the most promising composition. PMID:22457606

  9. Integration of toxicological and chemical tools to assess the bioavailability of metals and energetic compounds in contaminated soils.

    PubMed

    Berthelot, Yann; Valton, Emeline; Auroy, Aurélie; Trottier, Bertin; Robidoux, Pierre Yves

    2008-12-01

    Bioavailability is critical for understanding effects that might result from exposure of biota to contaminated soils. Soils from military range and training areas (RTAs) are contaminated principally by energetic materials (EM) and metals. Their chemical characteristics are relatively well known and toxicity assessment of soils from RTAs are in some cases available. However, bioavailability on these sites needs to be comprehensively characterized. A holistic approach to bioavailability, incorporating both chemical and earthworm toxicological indicators, was applied to soils from an anti-tank firing range at a Canadian Forces Base. Results showed that HMX and the metals Zn, Pb, Bi and Cd, though not consistently the prevailing toxicants, were the most accessible to earthworms. Some metals (notably Cu, Zn, Cr and Bi) were also accumulated in earthworm tissue but those were not necessarily expected given their bioaccessibility (i.e., the chemical availability of contaminants in the environment for the organisms) at the beginning of the exposure. The tested soils impaired earthworm reproduction and reduced adult growth. Measurement of selected sublethal parameters indicated that lysosomal integrity (determined as the neutral red retention time--NRRT) was decreased, while elevated superoxide dismutase (SOD) activity suggested that earthworms experienced oxidative stress. The correspondence between the NRRT and metal contamination pattern suggested that metals may be the main cause of lysosomal disruption in EM-contaminated soils. The approach to bioavailability appraisal adopted in this case appears to be a promising practice for site-specific assessment of contaminated land. PMID:18829064

  10. Formation and reactions of negative ions relevant to chemical ionization mass spectrometry. I. Cl mass spectra of organic compounds produced by F? reactions

    PubMed Central

    Tiernan, T. O.; Chang, C.; Cheng, C. C.

    1980-01-01

    A systematic study of the negative-ion chemical ionization mass spectra produced by the reaction of F? with a wide variety of organic compounds has been accomplished. A time-of-flight mass spectrometer fitted with a modified high pressure ion source was employed for these experiments. The F? reagent ion was generated from CF3H or NF3, typically at an ion source pressure of 100 ?m. In pure NF3, F? is the major ion formed and constitutes more than 90% of the total ion intensity. While F? is also the major primary ion formed in pure CF3H, it undergoes rapid ion-molecule reactions at elevated source pressures, yielding (HF)nF? (n = 1?3) ions, which makes CF3H less suitable as a chemical ionization reagent gas. Among the organic compounds investigated were carboxylic acids, ketones, aldehydes, esters, alcohols, phenols, halides, nitriles, nitrobenzene, ethers, amines and hydrocarbons. An intense (M ? 1)? ion was observed in the F? chemical ionization mass spectra of carboxylic acids, ketones, aldehydes and phenols. Alcohols yield only (M + F)? ions upon reaction with F?. A weaker (M + F)? ion was also detected in the F? chemical ionization spectra of carboxylic acids, aldehydes, ketones and nitriles. The F? chemical ionization mass spectra of esters, halides, nitriles, nitrobenzene and ethers are characterized primarily by the ions, RCOO?, X?, CN?, NO2?, and OR?, respectively. In addition, esters show a very weak (M ? 1)? ion (except formates). In the F? chemical ionization spectra of some aliphatic alkanes and o-xylene, a very weak (M + F)? ion was observed. Amines and aliphatic alkenes exhibit only insignificant fragment ions under similar conditions, while aromatic hydrocarbons, such as benzene and toluene are not reactive at all with the F? ion. The mechanisms of the various reactions mentioned are discussed, and several experimental complications are noted. In still other studies, the effects of varying several experimental parameters, including source pressure, relative proportions of the reagent and analyte, and other ion source parameters, on the observed chemical ionization mass spectra were also investigated. In a mixture of NF3 and n-butanol, for example, the ratio of the intensities of the ions characteristic of the alcohol to that of the (HF)nF? ion was found to decrease with increasing sample pressure, with increasing NF3 pressure, and with increasing electron energy. No significant effects on the spectra were observed to result from variation of the source repeller field or the source temperature. The addition of argon to the source as a potential moderator did not alter the F? chemical ionization spectrum significantly, but the use of oxygen appears to inhibit formation of the (HF)nF? cluster ion. The advantages of using F? as a chemical ionization reagent are discussed, and comparisons are made with other reagent ions. PMID:7428746

  11. THE ORIGINS OF LIGHT AND HEAVY R-PROCESS ELEMENTS IDENTIFIED BY CHEMICAL TAGGING OF METAL-POOR STARS

    SciTech Connect

    Tsujimoto, Takuji; Shigeyama, Toshikazu

    2014-11-01

    Growing interests in neutron star (NS) mergers as the origin of r-process elements have sprouted since the discovery of evidence for the ejection of these elements from a short-duration ?-ray burst. The hypothesis of a NS merger origin is reinforced by a theoretical update of nucleosynthesis in NS mergers successful in yielding r-process nuclides with A > 130. On the other hand, whether the origin of light r-process elements are associated with nucleosynthesis in NS merger events remains unclear. We find a signature of nucleosynthesis in NS mergers from peculiar chemical abundances of stars belonging to the Galactic globular cluster M15. This finding combined with the recent nucleosynthesis results implies a potential diversity of nucleosynthesis in NS mergers. Based on these considerations, we are successful in the interpretation of an observed correlation between [light r-process/Eu] and [Eu/Fe] among Galactic halo stars and accordingly narrow down the role of supernova nucleosynthesis in the r-process production site. We conclude that the tight correlation by a large fraction of halo stars is attributable to the fact that core-collapse supernovae produce light r-process elements while heavy r-process elements such as Eu and Ba are produced by NS mergers. On the other hand, stars in the outlier, composed of r-enhanced stars ([Eu/Fe] ? +1) such as CS22892-052, were exclusively enriched by matter ejected by a subclass of NS mergers that is inclined to be massive and consist of both light and heavy r-process nuclides.

  12. Medical Research and Evaluation Facility (MREF) and studies supporting the Medical Chemical Defense Program on Task 89-01: Screening of candidate pretreatment and therapeutic compounds in in vivo models. Final report Jul 89-Sep 91

    SciTech Connect

    Olson, C.T.; Kiser, R.C.; Dill, G.S.

    1992-02-01

    This task was a continuation of Task 86-29 initiated for Contract D. It provided in vivo screens for evaluating the efficacy of candidate pretreatment and treatment compounds submitted by the Drug Assessment Division of U.S. Army Medical Research of Chemical Defense against soman, tabun, and/or cyanide. A total of 578 compounds were received for testing and their maximum solubility in-vehicles comparable with in vivo testing in mice was determined. Range-finding and median lethal dose determinations following IM and/or oral administrations were conducted for 436 compounds submitted for nerve agent screening and range finding and median lethal dose determinations following IP administration were conducted for up to 142 compounds submitted for cyanide screening. Of 332 compounds evaluated, 154 passed the GD treatment efficacy evaluation, and 90 of 156 compounds submitted passed the GA treatment efficacy evaluation. For pretreatment studies against a GD challenge, 224 of 379 compounds submitted passed the IM efficacy evaluation and 96 of 143 compounds submitted passed the oral efficacy evaluation. Only 12 of 133 compounds evaluated as cyanide pretreatment compounds passed the efficacy evaluations. The mission of Task 89-01 was combined under Task 91-20 for the duration of Contract DAMD17-89-C-9050.

  13. Exome sequencing identifies novel compound heterozygous IFNA4 and IFNA10 mutations as a cause of impaired function in Crohn’s disease patients

    PubMed Central

    Xiao, Chuan-Xing; Xiao, Jing-Jing; Xu, Hong-Zhi; Wang, Huan-Huan; Chen, Xu; Liu, Yuan-Sheng; Li, Ping; Shi, Ying; Nie, Yong-Zhan; Li, Shao; Wu, Kai-Chun; Liu, Zhan-Ju; Ren, Jian-Lin; Guleng, Bayasi

    2015-01-01

    Previous studies have highlighted the role of genetic predispositions in disease, and several genes had been identified as important in Crohn’s disease (CD). However, many of these genes are likely rare and not associated with susceptibility in Chinese CD patients. We found 294 shared identical variants in the CD patients of which 26 were validated by Sanger sequencing. Two heterozygous IFN variants (IFNA10 c.60 T?>?A; IFNA4 c.60 A?>?T) were identified as significantly associated with CD susceptibility. The single-nucleotide changes alter a cysteine situated before the signal peptide cleavage site to a stop code (TGA) in IFNA10 result in the serum levels of IFNA10 were significantly decreased in the CD patients compared to the controls. Furthermore, the IFNA10 and IFNA4 mutants resulted in an impairment of the suppression of HCV RNA replication in HuH7 cells, and the administration of the recombinant IFN subtypes restored DSS-induced colonic inflammation through the upregulation of CD4+ Treg cells. We identified heterozygous IFNA10 and IFNA4 variants as a cause of impaired function and CD susceptibility genes in Chinese patients from multiple center based study. These findings might provide clues in the understanding of the genetic heterogeneity of CD and lead to better screening and improved treatment. PMID:26000985

  14. One-Dimensional Western Blotting Coupled to LC-MS/MS Analysis to Identify Chemical-Adducted Proteins in Rat Urine

    PubMed Central

    Labenski, Matthew T.; Fisher, Ashley A.; Monks, Terrence J.; Lau, Serrine S.

    2014-01-01

    The environmental toxicant hydroquinone (HQ) and its glutathione conjugates (GSHQs) cause renal cell necrosis via a combination of redox cycling and the covalent adduction of proteins within the S3 segment of the renal proximal tubules in the outer stripe of the outer medulla (OSOM). Following administration of 2-(glutathion-S-yl)HQ (MGHQ) (400 µmol/kg, i.v., 2 h) to Long Evans (wild-type Eker) rats, Western analysis utilizing an antibody specific for quinol–thioether metabolites of HQ revealed the presence of large amounts of chemical–protein adducts in both the OSOM and urine. By aligning the Western blot film with a parallel gel stained for protein, we can isolate the adducted proteins for LC-MS/MS analysis. Subsequent database searching can identify the specific site(s) of chemical adduction within these proteins. Finally, a combination of software programs can validate the identity of the adducted peptides. The site-specific identification of covalently adducted and oxidized proteins is a prerequisite for understanding the biological significance of chemical-induced posttranslational modifications (PTMs) and their toxicological significance. PMID:20972763

  15. Use of solid waste for chemical stabilization: Adsorption isotherms and {sup 13}C solid-state NMR study of hazardous organic compounds sorbed on coal fly ash

    SciTech Connect

    Netzel, D.A.; Lane, D.C.; Rovani, J.F.; Cox, J.D.; Clark, J.A.; Miknis, F.P.

    1993-09-01

    Adsorption of hazardous organic compounds on the Dave Johnston plant fly ash is described. Fly ash from Dave Johnston and Laramie River power plants were characterized using elemental, x-ray, and {sup 29}Si NMR; the Dave Johnston (DJ) fly ash had higher quartz contents, while the Laramie River fly ash had more monomeric silicate anions. Adsorption data for hydroaromatics and chlorobenzenes indicate that the adsorption capacity of DJ coal fly ash is much less than that of activated carbon by a factor of >3000; but it is needed to confirm that solid-gas and solid-liquid equilibrium isotherms can indeed be compared. However, for pyridine, pentachlorophenol, naphthalene, and 1,1,2,2-tetrachloroethane, the DJ fly ash appears to adsorb these compounds nearly as well as activated carbon. {sup 13}C NMR was used to study the adsorption of hazardous org. cpds on coal fly ash; the nuclear spin relaxation times often were very long, resulting in long experimental times to obtain a spectrum. Using a jumbo probe, low concentrations of some hazardous org. cpds could be detected; for pentachlorophenol adsorbed onto fly ash, the chemical shift of the phenolic carbon was changed. Use of NMR to study the adsorption needs further study.

  16. Source apportionment of human personal exposure to volatile organic compounds in homes, offices and outdoors by chemical mass balance and genetic algorithm receptor models.

    PubMed

    Gokhale, Sharad; Kohajda, Tibor; Schlink, Uwe

    2008-12-15

    A number of past studies have shown the prevalence of a considerable amount of volatile organic compounds (VOCs) in workplace, home and outdoor microenvironments. The quantification of an individual's personal exposure to VOCs in each of these microenvironments is an essential task to recognize the health risks. In this paper, such a study of source apportionment of the human exposure to VOCs in homes, offices, and outdoors has been presented. Air samples, analysed for 25 organic compounds and sampled during one week in homes, offices, outdoors and close to persons, at seven locations in the city of Leipzig, have been utilized to recognize the concentration pattern of VOCs using the chemical mass balance (CMB) receptor model. In result, the largest contribution of VOCs to the personal exposure is from homes in the range of 42 to 73%, followed by outdoors, 18 to 34%, and the offices, 2 to 38% with the corresponding concentration ranges of 35 to 80 microg m(- 3), 10 to 45 microg m(- 3) and 1 to 30 microg m(- 3) respectively. The species such as benzene, dodecane, decane, methyl-cyclopentane, triethyltoluene and trichloroethylene dominate outdoors; methyl-cyclohexane, triethyltoluene, nonane, octane, tetraethyltoluene, undecane are highest in the offices; while, from the terpenoid group like 3-carane, limonene, a-pinene, b-pinene and the aromatics toluene and styrene most influence the homes. A genetic algorithm (GA) model has also been applied to carry out the source apportionment. Its results are comparable with that of CMB. PMID:18822447

  17. Assessment of the deoxyribonucleic acid damage caused by occupational exposure to chemical compounds in Isfahan Polyacryl Company

    PubMed Central

    Etebari, Mahmoud; Jafarian-Dehkordi, Abbas; Kahookar, Ahmad; Moradi, Shahla

    2014-01-01

    Background: Chemical pollutants found in industrial environments can cause chronic genotoxicity in vulnerable individuals during the long-term exposure. The primary purpose of the present study was to assess the deoxyribonucleic acid (DNA) damage caused by occupational exposure to industrial chemicals and secondary purpose is to investigate the effect of possible risk factors of genotoxicity. Materials and Methods: The blood samples of the workers of Isfahan Polyacryl Company were evaluated in terms of genotoxicity using the comet assay method. The percentage of DNA in the tail and tail moment were measured and DNA damage was evaluated. Furthermore, the effect of age, smoking, duration of working in the company and working in two parts of the company on the degree of vulnerability to genotoxicity was assessed. Results: The amount of DNA damage in the target group (the production line workers) was significantly higher than the control group (the staffs), 3.87 versus 1.52 as tail moment, (P < 0.0001). DNA damage was significantly higher in smoker groups compared with non-smoker target group and control group, 4.18 versus 3.07 and 1.52 respectively as tail moment, (P < 0.0001). Furthermore, it was higher in person working in two different parts of the company compared to those work in one part and control group, 4.63 versus 3.74 and 1.52 respectively as tail moment, (P < 0.0001). Conclusion: Occupational exposure to Polyacryl caused DNA damage. Smoking and working in two parts of the company may have a significant role in DNA damage. PMID:25197297

  18. THP-1 monocytes but not macrophages as a potential alternative for CD34{sup +} dendritic cells to identify chemical skin sensitizers

    SciTech Connect

    Lambrechts, Nathalie Verstraelen, Sandra Lodewyckx, Hanne; Felicio, Ana; Hooyberghs, Jef; Witters, Hilda; Tendeloo, Viggo van; Cauwenberge, Paul van; Nelissen, Inge; Heuvel, Rosette van den; Schoeters, Greet

    2009-04-15

    Early detection of the sensitizing potential of chemicals is an emerging issue for chemical, pharmaceutical and cosmetic industries. In our institute, an in vitro classification model for prediction of chemical-induced skin sensitization based on gene expression signatures in human CD34{sup +} progenitor-derived dendritic cells (DC) has been developed. This primary cell model is able to closely mimic the induction phase of sensitization by Langerhans cells in the skin, but it has drawbacks, such as the availability of cord blood. The aim of this study was to investigate whether human in vitro cultured THP-1 monocytes or macrophages display a similar expression profile for 13 predictive gene markers previously identified in DC and whether they also possess a discriminating capacity towards skin sensitizers and non-sensitizers based on these marker genes. To this end, the cell models were exposed to 5 skin sensitizers (ammonium hexachloroplatinate IV, 1-chloro-2,4-dinitrobenzene, eugenol, para-phenylenediamine, and tetramethylthiuram disulfide) and 5 non-sensitizers (L-glutamic acid, methyl salicylate, sodium dodecyl sulfate, tributyltin chloride, and zinc sulfate) for 6, 10, and 24 h, and mRNA expression of the 13 genes was analyzed using real-time RT-PCR. The transcriptional response of 7 out of 13 genes in THP-1 monocytes was significantly correlated with DC, whereas only 2 out of 13 genes in THP-1 macrophages. After a cross-validation of a discriminant analysis of the gene expression profiles in the THP-1 monocytes, this cell model demonstrated to also have a capacity to distinguish skin sensitizers from non-sensitizers. However, the DC model was superior to the monocyte model for discrimination of (non-)sensitizing chemicals.

  19. Identifying the best iron-peak and ?-capture elements for chemical tagging: The impact of the number of lines on measured scatter

    NASA Astrophysics Data System (ADS)

    Adibekyan, V.; Figueira, P.; Santos, N. C.; Sousa, S. G.; Faria, J. P.; Delgado-Mena, E.; Oshagh, M.; Tsantaki, M.; Hakobyan, A. A.; González Hernández, J. I.; Suárez-Andrés, L.; Israelian, G.

    2015-11-01

    Aims: The main goal of this work is to explore which elements carry the most information about the birth origin of stars and, as such, which are best suited for chemical tagging. Methods: We explored different techniques to minimize the effect of outlier value lines in the abundances by using Ni abundances derived for 1111 FGK-type stars. We evaluate how the limited number of spectral lines can affect the final chemical abundance. Then we make an efficient even footing comparison of the [X/Fe] scatter between the elements that have a different number of observable spectral lines in the studied spectra. Results: When several spectral lines are available, we find that the most efficient way of calculating the average abundance of elements is to use a weighted mean (WM), whereby we consider the distance from the median abundance as a weight. This method can be used effectively without removing suspected outlier lines. When the same number of lines are used to determine chemical abundances, we show that the [X/Fe] star-to-star scatter for iron group and ?-capture elements is almost the same. The largest scatter among the studied elements, was observed for Al and the smallest for Cr and Ni. Conclusions: We recommend caution when comparing [X/Fe] scatters among elements where a different number of spectral lines are available. A meaningful comparison is necessary to identify elements that show the largest intrinsic scatter, which can then be used for chemical tagging. Appendices are available in electronic form at http://www.aanda.org

  20. A rapid dissolution procedure to aid initial nuclear forensics investigations of chemically refractory compounds and particles prior to gamma spectrometry.

    PubMed

    Reading, David G; Croudace, Ian W; Warwick, Phillip E; Britton, Richard

    2015-11-01

    A rapid and effective preparative procedure has been evaluated for the accurate determination of low-energy (40-200 keV) gamma-emitting radionuclides ((210)Pb, (234)Th, (226)Ra, (235)U) in uranium ores and uranium ore concentrates (UOCs) using high-resolution gamma ray spectrometry. The measurement of low-energy gamma photons is complicated in heterogeneous samples containing high-density mineral phases and in such situations activity concentrations will be underestimated. This is because attenuation corrections, calculated based on sample mean density, do not properly correct where dense grains are dispersed within a less dense matrix (analogous to a nugget effect). The current method overcomes these problems using a lithium tetraborate fusion that readily dissolves all components including high-density, self-attenuating minerals/compounds. This is the ideal method for dissolving complex, non-volatile components in soils, rocks, mineral concentrates, and other materials where density reduction is required. Lithium borate fusion avoids the need for theoretical efficiency corrections or measurement of matrix matched calibration standards. The resulting homogeneous quenched glass produced can be quickly dissolved in nitric acid producing low-density solutions that can be counted by gamma spectrometry. The effectiveness of the technique is demonstrated using uranium-bearing Certified Reference Materials and provides accurate activity concentration determinations compared to the underestimated activity concentrations derived from direct measurements of a bulk sample. The procedure offers an effective solution for initial nuclear forensic studies where complex refractory minerals or matrices exist. It is also significantly faster, safer and simpler than alternative approaches. PMID:26572834